Prof Charalambos Antoniades

Research Area: Cell and Molecular Biology
Technology Exchange: Biobanking, Drug discovery, Ex vivo models, Immunohistochemistry, In vivo imaging, Mouse models and SNP typing
Scientific Themes: Cardiovascular Science and Diabetes, Endocrinology & Metabolism
Web Links:

The interplay between adipose tissue and vascular/myocardial redox signalling

Adipose tissue is now considered to be a “biochemical factory” in the human body, producing a wide range of bioactive molecules, such as adipokines. These molecules exert local autocrine effects, but they also have paracrine and endocrine properties, and may play a critical role in the regulation of redox state and signalling in various tissues, such as the vascular wall and myocardium. Our group studies the mechanisms by which different adipose tissue depots in the human body affect vascular and myocardial redox state in atherosclerosis. We also search for novel therapeutic strategies targeting vascular and myocardial redox signalling directly or through changes in the crosstalk between adipose tissue and cardiovascular system.

Our group undertakes translational research, moving from bench to bedside and vice versa. We use various clinical research tools, such as non-invasive imaging and others, for the evaluation of vascular / myocardial function. This includes studies on human tissues; we have developed a number of ex vivo models of human tissue (vessels, myocardium and adipose tissue) for translational research, which are complemented by tissue and cell culture techniques. We have also established a large bioresource of human vascular, myocardial and adipose tissue in collaboration with other academic institutions across the world (The Oxford Heart Vessels & Fat (ox-HVF) cohort) and this is currently being used to support hypothesis driven research in the field of vascular and myocardial redox state regulation.

In our lab state-of-the-art techniques are used to visualise and quantify vascular and myocardial free radical production.

Using genetic tools to identify patients with pre-specified genetic traits, enables us to apply a “recruit-by-genotype” approach to address biological questions related to the cross-talk between adipose tissue and vascular/myocardial redox signalling in human cardiovascular disease.

We are also using state-of-the-art non-invasive imaging techniques (advanced ultrasound and CT imaging techniques) to study the structure and function of the cardiovascular system and explore its interactions with the adipose tissue. This programme of work led to the recent discovery of the "inside-to-outside" signals from the human cardiovascular system to the adipose tissue, and allowed the development of new clinical applications of cardiovascular imaging.

Since 2015, the group runs the Oxford Cardiovascular Computed Tomography programme, in partnership with the Manor Hospital, supporting the use of state-of-the-art cardiovascular CT imaging by groups within the University of Oxford.       

 Our group also organises small-scale randomised clinical trials that include extensive cardiovascular phenotyping, testing the effects of treatments (statins, folates etc) on the biology of the human vascular wall, myocardium and adipose tissue. 

Group members:

Alex Antonopoulos (post-doctoral clinical research fellow)

Piotr Orlowski (Senior post doctoral scientist)

Fabio Sanna (post doctoral scientist)

Nadia Akawi (Post-doctoral scientist)

Costas Psarros (Post doctoral research fellow)

Laura Herdman (Clinical researcher)

Sheena Thomas (Senior radiographer)

Marios Margaritis (DPhil student)

Akansha Tarun (DPhil Student)

Ioannis Akoumianakis (DPhil student)

Evangelos Oikonomou (DPhil Student)

Patients and public involvement in research:

Patient and public involvement in research is a top priority of the group. We are seeking for volunteers, patients or members of the public who are willing to provide feedback on the design and monitoring of the group’s clinical studies. Please contact us on antoniad@well.ox.ac.uk or heartresearch@cardiov.ox.ac.uk for further information on how to participate.    

Name Department Institution Country
Prof Dimitris Tousoulis 1st Department of Cardiology ( http://cardiology.med.uoa.gr/ ) University of Athens Greece
Prof Rajesh Kharbanda Cardiovascular Medicine Oxford University, John Radcliffe Hospital United Kingdom
Emeritus Professor John Stradling (NDM) Experimental Medicine Division Oxford University, Churchill Hospital United Kingdom
Prof Keith Channon FMedSci FRCP Cardiovascular Medicine Oxford University, John Radcliffe Hospital United Kingdom
Prof Stefan Neubauer FMedSci FRCP Cardiovascular Medicine Oxford University, John Radcliffe Hospital United Kingdom
Prof Alison Noble FREng (MPLS) Oxford University,
Prof Stephan Achenbach Erlangen University Germany
Prof Dennis Cokkinos Institute of Biomedical Research, Athens Academy of Sciences Greece
Prof Barbara Casadei FMedSci FRCP Cardiovascular Medicine Oxford University, West Wing, John Radcliffe Hospital United Kingdom
Prof David Lefer LSU, New Orleans United States
Antonopoulos AS, Sanna F, Sabharwal N, Thomas S, Oikonomou EK, Herdman L, Margaritis M, Shirodaria C, Kampoli AM, Akoumianakis I et al. 2017. Detecting human coronary inflammation by imaging perivascular fat. Sci Transl Med, 9 (398), | Show Abstract | Read more

Early detection of vascular inflammation would allow deployment of targeted strategies for the prevention or treatment of multiple disease states. Because vascular inflammation is not detectable with commonly used imaging modalities, we hypothesized that phenotypic changes in perivascular adipose tissue (PVAT) induced by vascular inflammation could be quantified using a new computerized tomography (CT) angiography methodology. We show that inflamed human vessels release cytokines that prevent lipid accumulation in PVAT-derived preadipocytes in vitro, ex vivo, and in vivo. We developed a three-dimensional PVAT analysis method and studied CT images of human adipose tissue explants from 453 patients undergoing cardiac surgery, relating the ex vivo images with in vivo CT scan information on the biology of the explants. We developed an imaging metric, the CT fat attenuation index (FAI), that describes adipocyte lipid content and size. The FAI has excellent sensitivity and specificity for detecting tissue inflammation as assessed by tissue uptake of 18F-fluorodeoxyglucose in positron emission tomography. In a validation cohort of 273 subjects, the FAI gradient around human coronary arteries identified early subclinical coronary artery disease in vivo, as well as detected dynamic changes of PVAT in response to variations of vascular inflammation, and inflamed, vulnerable atherosclerotic plaques during acute coronary syndromes. Our study revealed that human vessels exert paracrine effects on the surrounding PVAT, affecting local intracellular lipid accumulation in preadipocytes, which can be monitored using a CT imaging approach. This methodology can be implemented in clinical practice to noninvasively detect plaque instability in the human coronary vasculature.

Akoumianakis I, Antoniades C. 2017. Dipeptidyl peptidase IV inhibitors as novel regulators of vascular disease. Vascul Pharmacol, | Show Abstract | Read more

Dipeptidyl peptidase IV (DPP-IV) has been revealed as an adipokine with potential relevance in cardiovascular disease (CVD), while clinically used DPP-IV inhibitors have demonstrated beneficial cardiovascular effects in several experimental studies. Perivascular adipose tissue (PVAT) is a unique adipose tissue depot in close anatomical proximity and bidirectional functional interaction with the vascular wall, which is a source of DPP-IV and its biology may be influenced by DPP-IV inhibition. Recently, DPP-IV inhibition has been associated with decreased local inflammation and oxidative stress both in the vascular wall and the PVAT, potentially regulating atherogenesis progression in vivo. DPP-IV inhibition may thus be a promising target in cardiovascular disease. However, the exact pleiotropic mechanisms that underlie the cardiovascular effects of DPP-IV inhibition need to be clarified, while the in vivo benefit of DPP-IV inhibition in humans remains unclear.

Lee R, Fischer R, Charles PD, Adlam D, Valli A, Di Gleria K, Kharbanda RK, Choudhury RP, Antoniades C, Kessler BM, Channon KM. 2017. A novel workflow combining plaque imaging, plaque and plasma proteomics identifies biomarkers of human coronary atherosclerotic plaque disruption. Clin Proteomics, 14 (1), pp. 22. | Show Abstract | Read more

BACKGROUND: Atherosclerotic plaque rupture is the culprit event which underpins most acute vascular syndromes such as acute myocardial infarction. Novel biomarkers of plaque rupture could improve biological understanding and clinical management of patients presenting with possible acute vascular syndromes but such biomarker(s) remain elusive. Investigation of biomarkers in the context of de novo plaque rupture in humans is confounded by the inability to attribute the plaque rupture as the source of biomarker release, as plaque ruptures are typically associated with prompt down-stream events of myocardial necrosis and systemic inflammation. METHODS: We developed a novel approach to identify potential biomarkers of plaque rupture by integrating plaque imaging, using optical coherence tomography, with both plaque and plasma proteomic analysis in a human model of angioplasty-induced plaque disruption. RESULTS: We compared two pairs of coronary plaque debris, captured by a FilterWire Device, and their corresponding control samples and found matrix metalloproteinase 9 (MMP9) to be significantly enriched in plaque. Plaque contents, as defined by optical coherence tomography, affect the systemic changes of MMP9. Disruption of lipid-rich plaque led to prompt elevation of plasma MMP9, whereas disruption of non-lipid-rich plaque resulted in delayed elevation of plasma MMP9. Systemic MMP9 elevation is independent of the associated myocardial necrosis and systemic inflammation (measured by Troponin I and C-reactive protein, respectively). This information guided the selection of a subset of subjects of for further label free proteomics analysis by liquid chromatography tandem mass spectrometry (LC-MS/MS). We discovered five novel, plaque-enriched proteins (lipopolysaccharide binding protein, Annexin A5, eukaryotic translocation initiation factor, syntaxin 11, cytochrome B5 reductase 3) to be significantly elevated in systemic circulation at 5 min after plaque disruption. CONCLUSION: This novel approach for biomarker discovery in human coronary artery plaque disruption can identify new biomarkers related to human coronary artery plaque composition and disruption.

Antoniades C. 2017. "Dysfunctional" adipose tissue in cardiovascular disease: A reprogrammable target or an innocent bystander? Cardiovasc Res, 113 (9), pp. 997-998. | Show Abstract | Read more

Metabolically abnormal obesity as well as type 2 diabetes, are related with fundamental changes in the interactions between adipose tissue and the cardiovascular system. This editorial article introduces a spotlight issue addressing the complex relationships between adipose tissue and the cardiovascular system, in health and disease.

Akoumianakis I, Antoniades C. 2017. The interplay between adipose tissue and the cardiovascular system: is fat always bad? Cardiovasc Res, 113 (9), pp. 999-1008. | Show Abstract | Read more

Obesity is a risk factor for cardiovascular disease (CVD). However, clinical research has revealed a paradoxically protective role for obesity in patients with chronic diseases including CVD, suggesting that the biological "quality" of adipose tissue (AT) may be more important than overall AT mass or body weight. Importantly, AT is recognized as a dynamic organ secreting a wide range of biologically active adipokines, microRNAs, gaseous messengers and other metabolites that affect the cardiovascular system in both endocrine and paracrine ways. Despite being able to mediate normal cardiovascular function under physiological conditions, AT undergoes a phenotypic shift characterised by acquisition of pro-oxidant and pro-inflammatory properties in cases of CVD. Crucially, recent evidence suggests that AT depots such as perivascular AT and epicardial AT are able to modify their phenotype in response to local signals of vascular and myocardial origin respectively. Utilisation of this unique property of certain AT depots to dynamically track cardiovascular biology may reveal novel diagnostic and prognostic tools against CVD. Better understanding of the mechanisms controlling the "quality" of AT secretome, as well as the communication links between AT and the cardiovascular system, is required for the efficient management of CVD.

Margaritis M, Sanna F, Lazaros G, Akoumianakis I, Patel S, Antonopoulos AS, Duke C, Herdman L, Psarros C, Oikonomou EK et al. 2017. Predictive value of telomere length on outcome following acute myocardial infarction: evidence for contrasting effects of vascular vs. blood oxidative stress. Eur Heart J, | Show Abstract | Read more

Aims: Experimental evidence suggests that telomere length (TL) is shortened by oxidative DNA damage, reflecting biological aging. We explore the value of blood (BTL) and vascular TL (VTL) as biomarkers of systemic/vascular oxidative stress in humans and test the clinical predictive value of BTL in acute myocardial infarction (AMI). Methods and results: In a prospective cohort of 290 patients surviving recent AMI, BTL measured on admission was a strong predictor of all-cause [hazard ratio (HR) [95% confidence interval (CI)]: 3.21 [1.46-7.06], P = 0.004] and cardiovascular mortality (HR [95% CI]: 3.96 [1.65-9.53], P = 0.002) 1 year after AMI (for comparisons of short vs. long BTL, as defined by a T/S ratio cut-off of 0.916, calculated using receiver operating characteristic analysis; P adjusted for age and other predictors). To explore the biological meaning of these findings, BTL was quantified in 727 consecutive patients undergoing coronary artery bypass grafting (CABG), and superoxide (O2.-) was measured in peripheral blood mononuclear cells (PBMNC). VTL/vascular O2.- were quantified in saphenous vein (SV) and mammary artery (IMA) segments. Patients were genotyped for functional genetic polymorphisms in P22ph°x (activating NADPH-oxidases) and vascular smooth muscle cells (VSMC) selected by genotype were cultured from vascular tissue. Short BTL was associated with high O2.- in PBMNC (P = 0.04) but not in vessels, whereas VTL was related to O2.- in IMA (ρ = -0.49, P = 0.004) and SV (ρ = -0.52, P = 0.01). Angiotensin II (AngII) incubation of VSMC (30 days), as a means of stimulating NADPH-oxidases, increased O2.- and reduced TL in carriers of the high-responsiveness P22ph°x alleles (P = 0.007). Conclusion: BTL predicts cardiovascular outcomes post-AMI, independently of age, whereas VTL is a tissue-specific (rather than a global) biomarker of vascular oxidative stress. The lack of a strong association between BTL and VTL reveals the importance of systemic vs. vascular factors in determining clinical outcomes after AMI.

Taggart DP, Amin S, Djordjevic J, Oikonomou EK, Thomas S, Kampoli AM, Sabharwal N, Antoniades C, Krasopoulos G. 2017. A prospective study of external stenting of saphenous vein grafts to the right coronary artery: the VEST II study. Eur J Cardiothorac Surg, 51 (5), pp. 952-958. | Show Abstract | Read more

OBJECTIVES: External stents significantly reduce intimal hyperplasia and improve lumen uniformity and flow pattern in saphenous vein grafts (SVG) 1 year after coronary artery bypass grafting. However, recent studies have shown that at 1 year there is a lower patency of externally stented SVG to the right coronary artery (RCA) (55-60%) when compared to the left sided coronary arteries (85-90%). In the current study, we investigated whether avoidance of both fixation of the external stent to the anastomoses and the use of metal clips to ligate SVG side branches would improve the early patency of externally stented SVG to the RCA. METHODS: Thirty patients received a SVG to the right territory supported with an external stent. Graft patency was confirmed at the end of surgery in all patients. The primary endpoint was SVG patency assessed by computed tomography angiography (CTA) at 3-6 months. Graft failure was defined as > 50% stenosis. RESULTS: Twenty-nine patients (96.6%) completed the follow up period and CT angiography data was available for a total of 43 SVGs, (29 supported and 14 unsupported SVGs) and 47 arterial grafts. Patency of stented SVGs was 86.2% (25/29 on CTA). All non-stented SVGs to the left territory were patent. Patency rates of the left internal mammary arteries and right internal mammary arteries grafts were 96.6% and 83.3%, respectively. CONCLUSIONS: Avoidance of both metallic clips to ligate side branches and of fixation of venous external support trial (VEST) stents to the anastomoses mark a significant improvement in patency of stented SVG to the right coronary territory.

Antonopoulos AS, Antoniades C. 2017. The role of epicardial adipose tissue in cardiac biology: classic concepts and emerging roles. J Physiol, 595 (12), pp. 3907-3917. | Show Abstract | Read more

Classic concepts about the role of epicardial adipose tissue (EpAT) in heart physiology include its role in cardiac metabolism, mechanical protection of coronaries, innervation and possibly cryoprotection of the heart too. Nevertheless, recent evidence has revealed that epicardial adipose tissue regulates multiple aspects of cardiac biology including myocardial redox state, intracellular Ca(2+) cycling, the electrophysiological and contractile properties of cardiomyocytes, cardiac fibrosis as well as coronary atherosclerosis progression. Moreover, it is now understood that the communication between EpAT and the heart is regulated by complex bidirectional pathways, since not only do adipokines regulate cardiac function, but also the heart affects EpAT biology via paracrine 'reverse' signalling. Such complex interactions as well as epicardial fat accumulation as a consequence of cardiac disease and epicardium to adipocyte differentiation should be taken into account by the clinical studies investigating EpAT as a risk marker and its potential as a therapeutic target against cardiovascular disease. Further in-depth exploration of the molecular mechanisms regulating the cross-talk between the heart and EpAT is expected to enhance our understanding regarding the role of the latter in cardiac physiology and relevant disease mechanisms.

Turnbull CD, Akoumianakis I, Antoniades C, Stradling JR. 2017. Overnight urinary isoprostanes as a marker of oxidative stress in obstructive sleep apnoea. Eur Respir J, 49 (2), pp. 1601787-1601787. | Read more

Lazaros G, Antonopoulos AS, Oikonomou EK, Vasileiou P, Oikonomou E, Stroumpouli E, Karavidas A, Antoniades C, Tousoulis D. 2017. Prognostic implications of epicardial fat volume quantification in acute pericarditis. Eur J Clin Invest, 47 (2), pp. 129-136. | Show Abstract | Read more

BACKGROUND: The pathophysiology of acute pericarditis remains largely unknown, and biomarkers are needed to identify patients susceptible to complications. As adipose tissue has a pivotal role in cardiovascular disease pathogenesis, we hypothesized that quantification of epicardial fat volume (EFV) provides prognostic information in patients with acute pericarditis. MATERIALS AND METHODS: Fifty (n = 50) patients with first diagnosis of acute pericarditis were enrolled in this study. Patients underwent a cardiac computerized tomography (CT) scan to quantify EFV on a dedicated workstation. Patients were followed up in hospital for atrial fibrillation (AF) development and up to 18 months for the composite clinical endpoint of development of constrictive, recurrent or incessant pericarditis or poor response to nonsteroidal anti-inflammatory drugs. RESULTS: Patients presenting with chest pain had lower EFV vs. patients without chest pain (167·2 ± 21·7 vs. 105·1 ± 11·1 cm(3) , respectively, P < 0·01); EFV (but not body mass index) was strongly positively correlated with pericardial effusion size (r = 0·395, P = 0·007) and associated with in-hospital AF. At follow-up, patients that reached the composite clinical endpoint had lower EFV (P < 0·05). After adjustment for age, EFV was associated with lower odds ratio for the composite clinical endpoint point of poor response to NSAIDs or the development of constrictive, recurrent or incessant pericarditis during follow-up (per 20 cm(3) increase in EFV: OR = 0·802 [0·656-0·981], P < 0·05). CONCLUSIONS: We report for the first time a significant association of EFV with the clinical features and the outcome of patients with acute pericarditis. Measurement of EFV by CT may have important prognostic implications in these patients.

Akoumianakis I, Tarun A, Antoniades C. 2016. Perivascular adipose tissue as a regulator of vascular disease pathogenesis: identifying novel therapeutic targets. Br J Pharmacol, | Show Abstract | Read more

Adipose tissue (AT) is an active endocrine organ with the ability to dynamically secrete a wide range of adipocytokines. Importantly, its secretory profile is altered in various cardiovascular disease states. AT surrounding vessels, or perivascular AT (PVAT), is recognized in particular as an important local regulator of vascular function and dysfunction. Specifically, PVAT has the ability to sense vascular paracrine signals and respond by secreting a variety of vasoactive adipocytokines. Due to the crucial role of PVAT in regulating many aspects of vascular biology, it may constitute a novel therapeutic target for the prevention and treatment of vascular disease pathogenesis. Signalling pathways in PVAT, such as those using adiponectin, H2 S, glucagon-like peptide 1 or pro-inflammatory cytokines, are among the potential novel pharmacological therapeutic targets of PVAT.

Antonopoulos AS, Oikonomou EK, Antoniades C, Tousoulis D. 2016. From the BMI paradox to the obesity paradox: the obesity-mortality association in coronary heart disease. Obes Rev, 17 (10), pp. 989-1000. | Show Abstract | Read more

Despite a strong association between body weight and mortality in the general population, clinical evidence suggests better clinical outcome of overweight or obese individuals with established coronary heart disease. This finding has been termed the 'obesity paradox', but its existence remains a point of debate, because it is mostly observed when body mass index (BMI) is used to define obesity. Inherent limitations of BMI as an index of adiposity, as well as methodological biases and the presence of confounding factors, may account for the observed findings of clinical studies. In this review, our aim is to present the data that support the presence of a BMI paradox in coronary heart disease and then explore whether next to a BMI paradox a true obesity paradox exists as well. We conclude by attempting to link the obesity paradox notion to available translational research data supporting a 'healthy', protective adipose tissue phenotype. © 2016 World Obesity.

Woodward L, Akoumianakis I, Antoniades C. 2016. Unravelling the adiponectin paradox: novel roles of adiponectin in the regulation of cardiovascular disease. Br J Pharmacol, | Show Abstract | Read more

Adipose tissue (AT) has recently been identified as a dynamic endocrine organ secreting a wide range of adipokines. Adiponectin is one such hormone, exerting endocrine and paracrine effects on the cardiovascular system. At a cellular and molecular level, adiponectin has anti-inflammatory, antioxidant and anti-apoptotic roles, thereby mitigating key mechanisms underlying cardiovascular disease (CVD) pathogenesis. However, adiponectin expression in human AT as well as its circulating levels are increased in advanced CVD states, and it is actually considered by many as a 'rescue hormone'. Due to the complex mechanisms regulating adiponectin's biosynthesis in the human AT, measurement of its levels as a biomarker in CVD is highly controversial, given that adiponectin exerts protective effects on the cardiovascular system but at the same time its increased levels flag advanced CVD. In this review article, we present the involvement of adiponectin in CVD pathogenesis and we discuss its role as a clinical biomarker.

Woodward LC, Antoniades C, Taggart DP. 2016. Intraoperative Vein Graft Preservation: What Is the Solution? Ann Thorac Surg, 102 (5), pp. 1736-1746. | Show Abstract | Read more

Saphenous vein graft (SVG) disease and subsequent vein graft failure remain a major problem after coronary artery bypass graft operations. In an effort to mitigate loss of endothelial viability, the vein is stored, intraoperatively, in a preservation solution. However, human SVG samples demonstrate endothelial denudation and dysfunction after such storage, the severity of which varies, depending on the medium. The paucity of clinical data evaluating preservation solutions is illustrated by the absence of optimal procedural protocol. This review evaluates the potential efficacy of different storage solutions in preserving vein grafts, in relation to a mechanistic understanding of SVG pathophysiology.

Antoniades C, Vilahur G, Scientists of Tomorrow group of the CBCS of the ESC. 2016. Scientists of Tomorrow at the Frontiers of Cardiovascular Biology 2016 in Florence: translating basic science into clinical practice is the next frontier. Cardiovasc Res, 111 (2), pp. 120-122. | Read more

Levelt E, Pavlides M, Banerjee R, Mahmod M, Kelly C, Sellwood J, Ariga R, Thomas S, Francis J, Rodgers C et al. 2016. Ectopic and Visceral Fat Deposition in Lean and Obese Patients With Type 2 Diabetes. J Am Coll Cardiol, 68 (1), pp. 53-63. | Show Abstract | Read more

BACKGROUND: Type 2 diabetes (T2D) and obesity are associated with nonalcoholic fatty liver disease, cardiomyopathy, and cardiovascular mortality. Both show stronger links between ectopic and visceral fat deposition, and an increased cardiometabolic risk compared with subcutaneous fat. OBJECTIVES: This study investigated whether lean patients (Ln) with T2D exhibit increased ectopic and visceral fat deposition and whether these are linked to cardiac and hepatic changes. METHODS: Twenty-seven obese patients (Ob) with T2D, 15 Ln-T2D, and 12 normal-weight control subjects were studied. Subjects underwent cardiac computed tomography, cardiac magnetic resonance imaging (MRI), proton and phosphorus MR spectroscopy, and multiparametric liver MR, including hepatic proton MRS, T1- and T2*-mapping yielding "iron-corrected T1" [cT1]. RESULTS: Diabetes, with or without obesity, was associated with increased myocardial triglyceride content (p = 0.01), increased hepatic triglyceride content (p = 0.04), and impaired myocardial energetics (p = 0.04). Although cardiac structural changes, steatosis, and energetics were similar between the T2D groups, epicardial fat (p = 0.04), hepatic triglyceride (p = 0.01), and insulin resistance (p = 0.03) were higher in Ob-T2D. Epicardial fat, hepatic triglyceride, and insulin resistance correlated negatively with systolic strain and diastolic strain rates, which were only significantly impaired in Ob-T2D (p < 0.001 and p = 0.006, respectively). Fibroinflammatory liver disease (elevated cT1) was only evident in Ob-T2D patients. cT1 correlated with hepatic and epicardial fat (p < 0.001 and p = 0.01, respectively). CONCLUSIONS: Irrespective of body mass index, diabetes is related to significant abnormalities in cardiac structure, energetics, and cardiac and hepatic steatosis. Obese patients with T2D show a greater propensity for ectopic and visceral fat deposition.

Akoumianakis I, Antoniades C. 2016. Is stress response a new link between adipose tissue and atherogenesis? The role of HSPs/HSF1. Cardiovasc Res, 111 (1), pp. 10-12. | Read more

Antoniades C, Lee R, Kohler M, Stradling J. 2016. Paradoxical decrease in isoprostane and increase in superoxide dismutase following CPAP withdrawal in OSA. Eur Respir J, 47 (3), pp. 1014-1015. | Read more

Antonopoulos AS, Margaritis M, Verheule S, Recalde A, Sanna F, Herdman L, Psarros C, Nasrallah H, Coutinho P, Akoumianakis I et al. 2016. Mutual Regulation of Epicardial Adipose Tissue and Myocardial Redox State by PPAR-γ/Adiponectin Signalling. Circ Res, 118 (5), pp. 842-855. | Show Abstract | Read more

RATIONALE: Adiponectin has anti-inflammatory effects in experimental models, but its role in the regulation of myocardial redox state in humans is unknown. Although adiponectin is released from epicardial adipose tissue (EpAT), it is unclear whether it exerts any paracrine effects on the human myocardium. OBJECTIVE: To explore the cross talk between EpAT-derived adiponectin and myocardial redox state in the human heart. METHODS AND RESULTS: EpAT and atrial myocardium were obtained from 306 patients undergoing coronary artery bypass grafting. Functional genetic polymorphisms that increase ADIPOQ expression (encoding adiponectin) led to reduced myocardial nicotinamide adenine dinucleotide phosphate oxidase-derived O2 (-), whereas circulating adiponectin and ADIPOQ expression in EpAT were associated with elevated myocardial O2 (-). In human atrial tissue, we demonstrated that adiponectin suppresses myocardial nicotinamide adenine dinucleotide phosphate oxidase activity, by preventing AMP kinase-mediated translocation of Rac1 and p47(phox) from the cytosol to the membranes. Induction of O2 (-) production in H9C2 cardiac myocytes led to the release of a transferable factor able to induce peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ expression in cocultured EpAT. Using a NOX2 transgenic mouse and a pig model of rapid atrial pacing, we found that oxidation products (such as 4-hydroxynonenal) released from the heart trigger peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ in EpAT. CONCLUSIONS: We demonstrate for the first time in humans that adiponectin directly decreases myocardial nicotinamide adenine dinucleotide phosphate oxidase activity via endocrine or paracrine effects. Adiponectin expression in EpAT is controlled by paracrine effects of oxidation products released from the heart. These effects constitute a novel defense mechanism of the heart against myocardial oxidative stress.

Fabritz L, Guasch E, Antoniades C, Bardinet I, Benninger G, Betts TR, Brand E, Breithardt G, Bucklar-Suchankova G, Camm AJ et al. 2016. Expert consensus document: Defining the major health modifiers causing atrial fibrillation: a roadmap to underpin personalized prevention and treatment. Nat Rev Cardiol, 13 (4), pp. 230-237. | Show Abstract | Read more

Despite remarkable advances in antiarrhythmic drugs, ablation procedures, and stroke-prevention strategies, atrial fibrillation (AF) remains an important cause of death and disability in middle-aged and elderly individuals. Unstructured management of patients with AF sharply contrasts with our detailed, although incomplete, knowledge of the mechanisms that cause AF and its complications. Altered calcium homeostasis, atrial fibrosis and ageing, ion-channel dysfunction, autonomic imbalance, fat-cell infiltration, and oxidative stress, in addition to a susceptible genetic background, contribute to the promotion, maintenance, and progression of AF. However, clinical management of patients with AF is currently guided by stroke risk parameters, AF pattern, and symptoms. In response to this apparent disconnect between the known pathophysiology of AF and clinical management, we propose a roadmap to develop a set of clinical markers that reflect the major causes of AF in patients. Thereby, the insights into the mechanisms causing AF will be transformed into a format that can underpin future personalized strategies to prevent and treat AF, ultimately informing better patient care.

Bang C, Antoniades C, Antonopoulos AS, Eriksson U, Franssen C, Hamdani N, Lehmann L, Moessinger C, Mongillo M, Muhl L et al. 2015. Intercellular communication lessons in heart failure. Eur J Heart Fail, 17 (11), pp. 1091-1103. | Show Abstract | Read more

Cell-cell or inter-organ communication allows the exchange of information and messages, which is essential for the coordination of cell/organ functions and the maintenance of homeostasis. It has become evident that dynamic interactions of different cell types play a major role in the heart, in particular during the progression of heart failure, a leading cause of mortality worldwide. Heart failure is associated with compensatory structural and functional changes mostly in cardiomyocytes and cardiac fibroblasts, which finally lead to cardiomyocyte hypertrophy and fibrosis. Intercellular communication within the heart is mediated mostly via direct cell-cell interaction or the release of paracrine signalling mediators such as cytokines and chemokines. However, recent studies have focused on the exchange of genetic information via the packaging into vesicles as well as the crosstalk of lipids and other paracrine molecules within the heart and distant organs, such as kidney and adipose tissue, which might all contribute to the pathogenesis of heart failure. In this review, we discuss emerging communication networks and respective underlying mechanisms which could be involved in cardiovascular disease conditions and further emphasize promising therapeutic targets for drug development.

Papageorgiou N, Androulakis E, Papaioannou S, Antoniades C, Tousoulis D. 2015. Homoarginine in the shadow of asymmetric dimethylarginine: from nitric oxide to cardiovascular disease Amino Acids, 47 (9), pp. 1741-1750. | Read more

Antonopoulos AS, Antoniades C, Tousoulis D. 2015. Epicardial Adipose Tissue and No-Reflow Phenomenon: Adipokines as Regulators of Coronary Microcirculation? Hellenic J Cardiol, 56 (4), pp. 320-323.

Papageorgiou N, Androulakis E, Papaioannou S, Antoniades C, Tousoulis D. 2015. Homoarginine in the shadow of asymmetric dimethylarginine: from nitric oxide to cardiovascular disease. Amino Acids, 47 (9), pp. 1741-1750. | Show Abstract | Read more

It is well known that the endothelium maintains the vascular homeostasis. Importantly, endothelial dysfunction is regarded as a key early step in the development of atherosclerosis. Back in the early 1990s, it was found that asymmetric dimethylarginine (ADMA), an arginine metabolite derived from L-arginine (Arg) residues in proteins by asymmetric dimethylation on its guanidine group, is an endogenous inhibitor of nitric oxide (NO) synthase (NOS) isoforms. Inhibition of NO synthesis from Arg by the endothelial NOS isoform (eNOS) leads to endothelial dysfunction. Due to this action, ADMA participates in the pathophysiology of atherosclerosis and potentially contributes to cardiovascular events. Nowadays, homoarginine (hArg) is considered as a new key player in atherogenesis. hArg is a non-essential, non-proteinogenic amino acid which is synthesized from Arg by arginine:glycine amidinotransferase (AGAT). hArg is structurally related to Arg; formally, hArg is by one methylene (CH2) group longer than Arg, and may serve as a substrate for NOS, thus contributing to NO synthesis. For several decades, the pathophysiological role of hArg has been entirely unknown. hArg has been in the shadow of ADMA. Clinical studies have sought to investigate the relationship between circulating hArg levels and human disease states as well as cardiovascular prognosis. Recent studies indicate that hArg is actively involved in the vascular homeostasis, yet the underlying mechanisms are incompletely understood. In this article, we review the available literature regarding the role of ADMA and hArg in endothelial dysfunction and in cardiovascular disease as well as the possible associations between these endogenous Arg derivatives.

Antonopoulos AS, Antoniades C, Tousoulis D. 2015. Unravelling the "adipokine paradox": When the classic proatherogenic adipokine leptin is deemed the beneficial one. Int J Cardiol, 197 pp. 125-127. | Show Abstract | Read more

Adipokines released by adipose tissue have been recognised as important players in the development of cardiovascular disease. Leptin is a well-studied adipokine with an important role in body metabolism and energy expenditure and leptin-deficiency or deficient leptin signalling results in excessive obesity and type 2 diabetes. Studies in cells and animal models support that leptin has a pro-atherogenic potential and exerts pro-hypertrophic effects on the heart. However, recent basic and clinical evidence suggests that leptin may also have a beneficial role in cardiovascular physiology. Notably, clinical studies have failed to convincingly link leptin with increased cardiovascular disease risk. We herein summarise the role of leptin in cardiovascular disease as another example of the 'adipokine paradox' and discuss the complexity in using serum adipokine levels as biomarkers in cardiovascular disease.

Stradling JR, Schwarz EI, Schlatzer C, Manuel AR, Lee R, Antoniades C, Kohler M. 2015. Biomarkers of oxidative stress following continuous positive airway pressure withdrawal: data from two randomised trials. Eur Respir J, 46 (4), pp. 1065-1071. | Show Abstract | Read more

There is conflicting evidence whether intermittent hypoxia in obstructive sleep apnoea (OSA) influences oxidative stress. We hypothesised that withdrawal of continuous positive airway pressure (CPAP) from patients with OSA would raise markers of oxidative stress.59 patients with CPAP-treated moderate-to-severe OSA (oxygen desaturation index (ODI) >20 events·h(-1)) were randomised 1:1 to either stay on CPAP (n=30) or change to sham CPAP (n=29) for 2 weeks. Using samples from two similar studies at two sites, we measured early morning blood malondialdehyde (MDA, a primary outcome in one study and a secondary outcome in the other), lipid hydroperoxides, total antioxidant capacity, superoxide generation from mononuclear cells and urinary F2-isoprostane. We also measured superoxide dismutase as a marker of hypoxic preconditioning. "Treatment" effects (sham CPAP versus CPAP) were calculated via linear regression.Sham CPAP provoked moderate-to-severe OSA (mean ODI 46 events·h(-1)), but blood markers of oxidative stress did not change significantly (MDA "treatment" effect (95% CI) -0.02 (-0.23 to +0.19) μmol·L(-1)). Urinary F2-isoprostane fell significantly by ~30% (-0.26 (-0.42 to -0.10) ng·mL(-1)) and superoxide dismutase increased similarly (+0.17 (+0.02 to +0.30) ng·mL(-1)).We found no direct evidence of increased oxidative stress in patients experiencing a return of their moderate-to-severe OSA. The fall in urinary F2-isoprostane and rise in superoxide dismutase implies that hypoxic preconditioning may have reduced oxidative stress.

Karimi Galougahi K, Antoniades C, Nicholls SJ, Channon KM, Figtree GA. 2015. Redox biomarkers in cardiovascular medicine. Eur Heart J, 36 (25), pp. 1576-b. | Show Abstract | Read more

The central role of oxidative signalling in cardiovascular pathophysiology positions biometric measures of redox state as excellent markers for research and clinical application. However, despite this tantalizing biological plausibility, no redox biomarker is currently in widespread clinical use. Major recent insights into the mechanistic complexities of redox signalling may yet provide the opportunity to identify markers that most closely reflect the underlying pathobiology. Such redox biomarkers may, in principle, quantify the integrated effects of various known and unknown pathophysiological drivers of cardiovascular disease processes. Recent advances with the greatest potential include assays measuring post-translational oxidative modifications that have significant cellular effects. However, analytical issues, including the relative instability of redox-modified products, remain a major technical obstacle. Appreciation of these challenges may facilitate future development of user-friendly markers with prognostic value in addition to traditional risk factors, and which could be used to guide personalized cardiovascular therapies. We review both established and recently identified biomarkers of redox signalling, and provide a realistic discussion of the many challenges that remain if they are to be incorporated into clinical practice. Despite the current lack of redox biomarkers in clinical application, the integral role of reactive oxygen species in pathogenesis of cardiovascular disease provides a strong incentive for continued efforts.

Akoumianakis ID, Antoniades CA. 2015. Studying Systemic Oxidative Stress in Heart Failure: Does It Have Any Role in Clinical Practice? Hellenic J Cardiol, 56 (5), pp. 402-405.

Clunie-O'Connor C, Smits AM, Antoniades C, Russell AJ, Yellon DM, Goumans MJ, Riley PR. 2015. The Derivation of Primary Human Epicardium-Derived Cells. Curr Protoc Stem Cell Biol, 35 pp. 2C.5.1-2C.512. | Show Abstract | Read more

To develop therapeutic strategies for the regeneration of lost heart muscle after myocardial infarction (MI), a source of functional new muscle cells and associated coronary vessels must be identified. The epicardium is a source of several cardiovascular cell types during heart development and is widely regarded as a resident progenitor population, which becomes dormant during adulthood. In adult mice, MI induces epicardial reactivation characterized by an upregulation of fetal genes and subsequent epicardium derived cell (EPDC) proliferation, migration, and differentiation. Determining whether the epicardium can be therapeutically targeted following cardiovascular disease requires an in vitro system for the study of adult human EPDCs (hEPDCs). This protocol describes techniques to establish and maintain human epicardium explant cultures from patient-derived right atrial appendage biopsies and documents methods to probe the resultant outgrowth of hEPDCs. The model facilitates a high-throughput approach to either genetic or chemical phenotypic screening for drug-like modifiers of hEPDC activation and potential cell fate.

Antonopoulos AS, Margaritis M, Coutinho P, Shirodaria C, Psarros C, Herdman L, Sanna F, De Silva R, Petrou M, Sayeed R et al. 2015. Adiponectin as a link between type 2 diabetes and vascular NADPH oxidase activity in the human arterial wall: the regulatory role of perivascular adipose tissue. Diabetes, 64 (6), pp. 2207-2219. | Show Abstract | Read more

Oxidative stress plays a critical role in the vascular complications of type 2 diabetes. We examined the effect of type 2 diabetes on NADPH oxidase in human vessels and explored the mechanisms of this interaction. Segments of internal mammary arteries (IMAs) with their perivascular adipose tissue (PVAT) and thoracic adipose tissue were obtained from 386 patients undergoing coronary bypass surgery (127 with type 2 diabetes). Type 2 diabetes was strongly correlated with hypoadiponectinemia and increased vascular NADPH oxidase-derived superoxide anions (O2˙(-)). The genetic variability of the ADIPOQ gene and circulating adiponectin (but not interleukin-6) were independent predictors of NADPH oxidase-derived O2˙(-). However, adiponectin expression in PVAT was positively correlated with vascular NADPH oxidase-derived O2˙(-). Recombinant adiponectin directly inhibited NADPH oxidase in human arteries ex vivo by preventing the activation/membrane translocation of Rac1 and downregulating p22(phox) through a phosphoinositide 3-kinase/Akt-mediated mechanism. In ex vivo coincubation models of IMA/PVAT, the activation of arterial NADPH oxidase triggered a peroxisome proliferator-activated receptor-γ-mediated upregulation of the adiponectin gene in the neighboring PVAT via the release of vascular oxidation products. We demonstrate for the first time in humans that reduced adiponectin levels in individuals with type 2 diabetes stimulates vascular NADPH oxidase, while PVAT "senses" the increased NADPH oxidase activity in the underlying vessel and responds by upregulating adiponectin gene expression. This PVAT-vessel interaction is identified as a novel therapeutic target for the prevention of vascular complications of type 2 diabetes.

Tousoulis D, Kourkouti P, Antoniades C, Briasoulis A, Siasos G, Vogiatzi G, Valatsou A, Oikonomou E, Hatzis G, Latsios G, Perrea D. 2014. Impact of folic acid administration in homocysteine levels, inflammation and in atherosclerotic plaque area in apoE deficient mice. Int J Cardiol, 177 (2), pp. 696-697. | Read more

Katsi V, Varounis C, Pavlidis AN, Alexopoulos N, Vlachopoulos C, Antoniades C, Vamvakou G, Tousoulis D, Stefanadis C, Kallikazaros I. 2015. Differences in arterial stiffness and target organ damage between native Greek patients and immigrants from Eastern European countries with essential hypertension. Int Angiol, 34 (4), pp. 407-412. | Show Abstract

AIM: The variance in hypertension-related sequelae between different ethnic groups is highly related to differences in socioeconomic conditions and lifestyle habits, but also to disparities in the awareness and treatment of the disease. In the present study, we sought to evaluate the target organ damage in a vulnerable hypertensive population, such as the Eastern European immigrants. METHODS: The study population consisted of 128 hypertensive patients: 67 immigrants from Eastern Europe and 61 native inhabitants. Anthropometric, biochemical and echocardiographic data were derived from both groups. Both groups underwent fundoscopic examination and pulse wave velocity (PWV) measurements for assessment of arterial stiffness. RESULTS: Although immigrants had lower body mass index compared to native inhabitants (P<0.001), they had significantly increased arterial stiffness (P=0.003). In multivariate analysis, higher carotid-femoral PWV was significantly associated with immigration status [β (SE)=0.935(0.443), P=0.041], after adjustment for smoking status. Moreover, immigrants had increased left atrial volume index (LAVI) (P<0.001), left ventricular mass index (P<0.001) and higher rates of left ventricular diastolic dysfunction (p=0.047). In multivariate analysis, LAVI was significantly associated with immigration status (β (SE)=5.17(1.93), P=0.01) after adjustment for serum glucose levels and age. Finally, immigrants had significantly higher levels of sodium urinary excretion (p=0.007) and lower glomerular filtration rate (P<0.001). CONCLUSION: Our findings suggest that hypertensive immigrants exhibit an aggravated arterial stiffness profile and increased risk of target organ damage. These findings could be attributed to differences in socioeconomic conditions and dietary habits.

Antonopoulos AS, Margaritis M, Coutinho P, Digby J, Patel R, Psarros C, Ntusi N, Karamitsos TD, Lee R, De Silva R et al. 2014. Reciprocal effects of systemic inflammation and brain natriuretic peptide on adiponectin biosynthesis in adipose tissue of patients with ischemic heart disease. Arterioscler Thromb Vasc Biol, 34 (9), pp. 2151-2159. | Show Abstract | Read more

OBJECTIVE: To explore the role of systemic inflammation in the regulation of adiponectin levels in patients with ischemic heart disease. APPROACH AND RESULTS: In a cross-sectional study of 575 subjects, serum adiponectin was compared between healthy subjects, patients with coronary artery disease with no/mild/severe heart failure (HF), and patients with nonischemic HF. Adiponectin expression and release from femoral, subcutaneous and thoracic adipose tissue was determined in 258 additional patients with coronary artery bypass grafting. Responsiveness of the various human adipose tissue depots to interleukin-6, tumor necrosis factor-α, and brain natriuretic peptide (BNP) was examined by using ex vivo models of human fat. The effects of inducible low-grade inflammation were tested by using the model of Salmonella typhi vaccine-induced inflammation in healthy individuals. In the cross-sectional study, HF strikingly increased adiponectin levels. Plasma BNP was the strongest predictor of circulating adiponectin and its release from all adipose tissue depots in patients with coronary artery bypass grafting, even in the absence of HF. Femoral AT was the depot with the least macrophages infiltration and the largest adipocyte cell size and the only responsive to systemic and ex vivo proinflammatory stimulation (effect reversible by BNP). Low-grade inflammation reduced circulating adiponectin levels, while circulating BNP remained unchanged. CONCLUSIONS: This study demonstrates the regional variability in the responsiveness of human adipose tissue to systemic inflammation and suggests that BNP (not systemic inflammation) is the main driver of circulating adiponectin in patients with advanced atherosclerosis even in the absence of HF. Any interpretation of circulating adiponectin as a biomarker should take into account the underlying disease state, background inflammation, and BNP levels.

Hatzis G, Tousoulis D, Papageorgiou N, Bouras G, Oikonomou E, Miliou A, Siasos G, Toutouzas K, Papaioannou S, Tsiamis E et al. 2014. Combined effects of smoking and interleukin-6 and C-reactive protein genetic variants on endothelial function, inflammation, thrombosis and incidence of coronary artery disease. Int J Cardiol, 176 (1), pp. 254-257. | Read more

Paschalis A, Tousoulis D, Demosthenous M, Antonopoulos A, Papaioannou S, Miliou A, Koumallos N, Antoniades C, Stefanadis C. 2014. Pre-operative inflammation and post-operative atrial fibrillation in coronary artery bypass surgery. Int J Cardiol, 173 (2), pp. 327-328. | Read more

Tousoulis D, Psarros C, Demosthenous M, Patel R, Antoniades C, Stefanadis C. 2014. Innate and adaptive inflammation as a therapeutic target in vascular disease: the emerging role of statins. J Am Coll Cardiol, 63 (23), pp. 2491-2502. | Show Abstract | Read more

Atherosclerosis, the main pathophysiological condition leading to cardiovascular disease (CVD), is now considered to be a chronic inflammatory condition. Statins are the most widely used and promising agents in treating CVD and are renowned for their pleiotropic lipid-lowering independent effects. Statins exert their anti-inflammatory effects on the vascular wall through a variety of molecular pathways of the innate and adaptive immune systems, their impact on the circulating levels of pro-inflammatory cytokines, and their effect on adhesion molecules. By inhibiting the mevalonate pathway and isoprenoid formation, statins account for the increase of nitric oxide bioavailability and the improvement of vascular and myocardial redox state by multiple different mechanisms (directly or indirectly through low-density lipoprotein [LDL] lowering). A large number of randomized control trials have shown that statins help in the primary and secondary prevention of cardiovascular events, not only via their lipid-lowering effect, but also due to their anti-inflammatory potential as well. In this paper, we examine the molecular pathways in which statins are implicated and exert their anti-inflammatory effects, and we focus specifically on their impact on innate and adaptive immunity systems. Finally, we review the most important clinical data for the role of statins in primary and secondary prevention of cardiovascular events.

Antoniades C, Channon KM. 2014. Statins: pleiotropic regulators of cardiovascular redox state. Antioxid Redox Signal, 20 (8), pp. 1195-1197. | Show Abstract | Read more

Lipid-lowering treatment with statins is one of the most effective therapeutic strategies in cardiovascular medicine because they reduce cardiovascular risk in both primary and secondary prevention. Despite the well-established links between low-density lipoprotein and cardiovascular risk, the clinical benefit from statin treatment is not fully explained by their lipid-lowering potential. A number of pleiotropic effects of statins have been described over the past decade, and their ability to suppress global oxidative stress is probably one of the most important mechanisms by which they exert their beneficial effects on the cardiovascular system. In this Forum, there are review articles discussing the molecular mechanisms by which statins modify redox signaling in the vasculature and the heart. They exert direct effects on the vascular wall and the myocardium or indirect by targeting the interactions between the cardiovascular system and adipose tissue or circulating cell types. The review articles in this Forum follow a translational approach and link the molecular mechanisms by which statins modify cardiovascular redox signaling with their clinical benefit in the prevention and treatment of cardiovascular diseases.

Antonopoulos AS, Margaritis M, Coutinho P, Digby J, Patel R, Psarros C, Ntusi N, Karamitsos TD, Lee R, De Silva R et al. 2014. Reciprocal effects of systemic inflammation and brain natriuretic peptide on adiponectin biosynthesis in adipose tissue of patients with ischemic heart disease Arteriosclerosis, Thrombosis, and Vascular Biology, 34 (9), pp. 2151-2159. | Read more

Hatzis G, Tousoulis D, Papageorgiou N, Bouras G, Oikonomou E, Miliou A, Siasos G, Toutouzas K, Papaioannou S, Tsiamis E et al. 2014. Combined effects of smoking and interleukin-6 and C-reactive protein genetic variants on endothelial function, inflammation, thrombosis and incidence of coronary artery disease International Journal of Cardiology, 176 (1), pp. 254-257. | Read more

Papageorgiou N, Tousoulis D, Miliou A, Hatzis G, Kozanitou M, Androulakis E, Charakida M, Antonopoulos A, Antoniades C, Briasoulis A et al. 2013. Combined effects of fibrinogen genetic variability on atherosclerosis in patients with or without stable angina pectoris: Focus on the coagulation cascade and endothelial function International Journal of Cardiology, 168 (5), pp. 4602-4607. | Show Abstract | Read more

Background Fibrinogen is a coagulation/inflammatory biomarker strongly associated with atherogenesis. Data have reported that the genetic variability on fibrinogen chains may affect the atherosclerotic process and the risk of coronary artery disease (CAD). We examined the combined effects of the G455A and the G58A fibrinogen genetic polymorphisms on prothrombotic profile, endothelial function and the risk of CAD in a Caucasian population. Methods We recruited 422 patients with angiographically documented CAD and 277 controls matched for age and gender. The two polymorphisms were genotyped by polymerase chain reaction and restriction endonuclease digestion. Fibrinogen and D-Dimers levels, as well as factors' (f) V, X activity were measured by standard coagulometry techniques. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery. Results The two polymorphisms had no significant effect on the risk for CAD. Although the 58AA subjects had not significantly different levels of fibrinogen compared with the 58GG + GA in both groups (p = NS), we importantly found that the 455AA homozygosity was associated with increased fibrinogen levels not only in the control group (p = 0.035), but also in the CAD group (p < 0.001) compared to the G allele carriers. Moreover, both the 58AA (p = 0.016) and 455AA homozygotes (p = 0.022) presented with higher levels of D-Dimers in the CAD group. Interestingly, the 455AA homozygotes had increased fV activity in the CAD group (p = 0.048). However, no significant effects were observed on fX activity and FMD. Conclusions Both fibrinogen polymorphisms are capable to modify the atherosclerotic process via their effects on the coagulation cascade. © 2013 Elsevier Ireland Ltd.

Margaritis M, Channon KM, Antoniades C. 2014. Statins as regulators of redox state in the vascular endothelium: beyond lipid lowering. Antioxid Redox Signal, 20 (8), pp. 1198-1215. | Show Abstract | Read more

SIGNIFICANCE: Endothelial dysfunction and the imbalance between nitric oxide (NO) and reactive oxygen species production in the vascular endothelium are important early steps in atherogenesis, a major socioeconomic health problem. Statins have well-established roles in primary and secondary prevention of cardiovascular disease (CVD), due to both their lipid-lowering capacity and their pleiotropic properties. It is therefore important to understand the mechanisms by which statins can modify endothelial function and affect atherogenesis. RECENT ADVANCES: In the last decade, the concept of statin pleiotropy has been reinforced by a large number of cell culture, animal, and translational studies. Statins have been shown to suppress the activity of pro-oxidant enzymes (such as NADPH oxidase) and pro-inflammatory transcriptional pathways in the endothelium. At the same time, they enhance endothelial NO synthase expression and activity while they also improve its enzymatic coupling. This leads to increased NO bioavailability and improved endothelial function. CRITICAL ISSUES: Despite significant recent advances, the exact mechanisms of statin pleitropy are still only partially understood. The vast majority of the published literature relies on animal studies, while the actual mechanistic studies in humans are limited. FUTURE DIRECTIONS: The success of statins as endothelium redox-modifying agents with a direct impact on clinical outcome highlights the importance of the endothelium as a therapeutic target in CVD. Better understanding of the mechanisms that underlie endothelial dysfunction could lead to the design of novel therapeutic strategies that target the vascular endothelium for the prevention and treatment of CVD.

Papageorgiou N, Tousoulis D, Androulakis E, Antoniades C, Tentolouris C, Stefanadis C. 2013. Inflammation and right ventricle: The hunting of the missing link International Journal of Cardiology, 168 (4), pp. 3152-3154. | Read more

Papaoikonomou S, Tousoulis D, Tentolouris N, Papadogiannis D, Miliou A, Hatzis G, Papageorgiou N, Antoniades C, Stefanadis C. 2013. The role of C-reactive protein genetic variability in the onset of carotid artery disease and renal function impairment in patients with diabetes mellitus type 2 International Journal of Cardiology, 168 (4), pp. 4331-4332. | Read more

Lee R, Antonopoulos AS, Alexopoulou Z, Margaritis M, Kharbanda RK, Choudhury RP, Antoniades C, Channon KM. 2013. Artifactual elevation of plasma sCD40L by residual platelets in patients with coronary artery disease International Journal of Cardiology, 168 (2), pp. 1648-1650. | Read more

Tousoulis D, Toli E, Miliou A, Papageorgiou N, Antoniades C, Kampoli AM, Hatzis G, Kormali L, Metaxa S, Papaoikonomou S et al. 2013. The impact of G5665T polymorphismof endothelin-1 gene, on endothelin-1 levels and left ventricular function in ischemic heart disease International Journal of Cardiology, 168 (2), pp. 1568-1569. | Read more

Antonopoulos AS, Tousoulis D, Antoniades C, Miliou A, Hatzis G, Papageorgiou N, Demosthenous M, Tentolouris C, Stefanadis C. 2013. Genetic variability on adiponectin gene affects myocardial infarction risk: The role of endothelial dysfunction International Journal of Cardiology, 168 (1), pp. 326-330. | Show Abstract | Read more

Background: Adiponectin is an adipokine with an important role in cardiovascular system conferring anti-inflammatory and anti-atherogenic effects. Two common single nucleotide polymorphisms (SNP) on adiponectin gene, rs2241766 and rs1501299, have been associated with insulin resistance and diabetes mellitus risk however their effects on cardiovascular risk remain unclear. We examined the impact of rs2241766 and rs1501299 on circulating adiponectin levels, endothelial function and cardiovascular disease risk. Methods: We recruited in total 594 subjects; 462 patients with angiographically confirmed coronary artery disease (CAD) and 132 controls matched for age and gender. rs2241766 and rs1501299 were genotyped by polymerase chain reaction and restriction endonuclease digestion. Serum adiponectin levels were determined by enzyme-linked immunosorbent assay. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery. Results: rs2241766 had no effects on circulating adiponectin levels or FMD. In subjects without CAD, carriers of the T/T alleles at rs1501299 had lower adiponectin levels (p = 0.001) and impaired endothelial function (p < 0.05). After multivariate adjustment none of the SNPs had any effect on CAD risk. However, carriers of the T allele at rs1501299 were at increased myocardial infarction (MI) risk, independently of classic risk factors (OR = 2.558 [95%CI = 1.587-4.123], p = 0.0001). The number of T alleles in both SNPs was strongly associated with MI history (p = 0.0001). Conclusions: rs1501299 polymorphism of adiponectin gene affects circulating adiponectin levels and endothelial function in subjects without CAD. Presence of the T variant at rs1501299 on adiponectin gene is independently associated with increased myocardial infarction risk. © 2012 Elsevier Ireland Ltd. All rights reserved.

Papageorgiou N, Tousoulis D, Androulakis E, Antoniades C, Tentolouris C, Stefanadis C. 2013. Inflammation and right ventricle: the hunting of the missing link. Int J Cardiol, 168 (4), pp. 3152-3154. | Read more

Margaritis M, Antonopoulos AS, Digby J, Lee R, Reilly S, Coutinho P, Shirodaria C, Sayeed R, Petrou M, De Silva R et al. 2013. Interactions between vascular wall and perivascular adipose tissue reveal novel roles for adiponectin in the regulation of endothelial nitric oxide synthase function in human vessels. Circulation, 127 (22), pp. 2209-2221. | Show Abstract | Read more

BACKGROUND: Adiponectin is an adipokine with potentially important roles in human cardiovascular disease states. We studied the role of adiponectin in the cross-talk between adipose tissue and vascular redox state in patients with atherosclerosis. METHODS AND RESULTS: The study included 677 patients undergoing coronary artery bypass graft surgery. Endothelial function was evaluated by flow-mediated dilation of the brachial artery in vivo and by vasomotor studies in saphenous vein segments ex vivo. Vascular superoxide (O2(-)) and endothelial nitric oxide synthase (eNOS) uncoupling were quantified in saphenous vein and internal mammary artery segments. Local adiponectin gene expression and ex vivo release were quantified in perivascular (saphenous vein and internal mammary artery) subcutaneous and mesothoracic adipose tissue from 248 patients. Circulating adiponectin was independently associated with nitric oxide bioavailability and O2(-) production/eNOS uncoupling in both arteries and veins. These findings were supported by a similar association between functional polymorphisms in the adiponectin gene and vascular redox state. In contrast, local adiponectin gene expression/release in perivascular adipose tissue was positively correlated with O2(-) and eNOS uncoupling in the underlying vessels. In ex vivo experiments with human saphenous veins and internal mammary arteries, adiponectin induced Akt-mediated eNOS phosphorylation and increased tetrahydrobiopterin bioavailability, improving eNOS coupling. In ex vivo experiments with human saphenous veins/internal mammary arteries and adipose tissue, we demonstrated that peroxidation products produced in the vascular wall (ie, 4-hydroxynonenal) upregulate adiponectin gene expression in perivascular adipose tissue via a peroxisome proliferator-activated receptor-γ-dependent mechanism. CONCLUSIONS: We demonstrate for the first time that adiponectin improves the redox state in human vessels by restoring eNOS coupling, and we identify a novel role of vascular oxidative stress in the regulation of adiponectin expression in human perivascular adipose tissue.

Papaoikonomou S, Tousoulis D, Tentolouris N, Papadogiannis D, Miliou A, Hatzis G, Papageorgiou N, Antoniades C, Stefanadis C. 2013. The role of C-reactive protein genetic variability in the onset of carotid artery disease and renal function impairment in patients with diabetes mellitus type 2. Int J Cardiol, 168 (4), pp. 4331-4332. | Read more

Tousoulis D, Vogiatzi G, Briasoulis A, Valatsou A, Nikolopoulou P, Papaxoinis K, Pantopoulou A, Papageorgiou N, Antoniades C, Perrea D, Stefanadis C. 2013. Improved limb perfusion and neoangiogenesis after intramuscular erythropoietin infusion in experimental model of limb ischemia International Journal of Cardiology, 165 (1), pp. 195-197. | Read more

Lee R, Antonopoulos AS, Alexopoulou Z, Margaritis M, Kharbanda RK, Choudhury RP, Antoniades C, Channon KM. 2013. Artifactual elevation of plasma sCD40L by residual platelets in patients with coronary artery disease. Int J Cardiol, 168 (2), pp. 1648-1650. | Read more

Tousoulis D, Toli E, Miliou A, Papageorgiou N, Antoniades C, Kampoli AM, Hatzis G, Kormali L, Metaxa S, Papaoikonomou S et al. 2013. The impact of G5665T polymorphism of endothelin-1 gene, on endothelin-1 levels and left ventricular function in ischemic heart disease. Int J Cardiol, 168 (2), pp. 1568-1569. | Read more

Papageorgiou N, Tousoulis D, Miliou A, Hatzis G, Kozanitou M, Androulakis E, Charakida M, Antonopoulos A, Antoniades C, Briasoulis A et al. 2013. Combined effects of fibrinogen genetic variability on atherosclerosis in patients with or without stable angina pectoris: focus on the coagulation cascade and endothelial function. Int J Cardiol, 168 (5), pp. 4602-4607. | Show Abstract | Read more

BACKGROUND: Fibrinogen is a coagulation/inflammatory biomarker strongly associated with atherogenesis. Data have reported that the genetic variability on fibrinogen chains may affect the atherosclerotic process and the risk of coronary artery disease (CAD). We examined the combined effects of the G455A and the G58A fibrinogen genetic polymorphisms on prothrombotic profile, endothelial function and the risk of CAD in a Caucasian population. METHODS: We recruited 422 patients with angiographically documented CAD and 277 controls matched for age and gender. The two polymorphisms were genotyped by polymerase chain reaction and restriction endonuclease digestion. Fibrinogen and D-Dimers levels, as well as factors' (f) V, X activity were measured by standard coagulometry techniques. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery. RESULTS: The two polymorphisms had no significant effect on the risk for CAD. Although the 58AA subjects had not significantly different levels of fibrinogen compared with the 58GG+GA in both groups (p=NS), we importantly found that the 455AA homozygosity was associated with increased fibrinogen levels not only in the control group (p=0.035), but also in the CAD group (p<0.001) compared to the G allele carriers. Moreover, both the 58AA (p=0.016) and 455AA homozygotes (p=0.022) presented with higher levels of D-Dimers in the CAD group. Interestingly, the 455AA homozygotes had increased fV activity in the CAD group (p=0.048). However, no significant effects were observed on fX activity and FMD. CONCLUSIONS: Both fibrinogen polymorphisms are capable to modify the atherosclerotic process via their effects on the coagulation cascade.

Tousoulis D, Antoniades C, Vlachopoulos C, Stefanadis C. 2013. Flow mediated dilation and carotid intima media thickness: Clinical markers or just research tools? International Journal of Cardiology, 163 (3), pp. 226-228. | Read more

Lee R, Adlam D, Antoniades C, Digby JE, Kharbanda RK, Choudhury RP, Channon KM. 2013. Heparin administration leads to rapid decrease in plasma matrix metalloproteinase-9 International Journal of Cardiology, 163 (2), pp. 212-213. | Read more

Antonopoulos AS, Tousoulis D, Antoniades C, Miliou A, Hatzis G, Papageorgiou N, Demosthenous M, Tentolouris C, Stefanadis C. 2013. Genetic variability on adiponectin gene affects myocardial infarction risk: the role of endothelial dysfunction. Int J Cardiol, 168 (1), pp. 326-330. | Show Abstract | Read more

BACKGROUND: Adiponectin is an adipokine with an important role in cardiovascular system conferring anti-inflammatory and anti-atherogenic effects. Two common single nucleotide polymorphisms (SNP) on adiponectin gene, rs2241766 and rs1501299, have been associated with insulin resistance and diabetes mellitus risk however their effects on cardiovascular risk remain unclear. We examined the impact of rs2241766 and rs1501299 on circulating adiponectin levels, endothelial function and cardiovascular disease risk. METHODS: We recruited in total 594 subjects; 462 patients with angiographically confirmed coronary artery disease (CAD) and 132 controls matched for age and gender. rs2241766 and rs1501299 were genotyped by polymerase chain reaction and restriction endonuclease digestion. Serum adiponectin levels were determined by enzyme-linked immunosorbent assay. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery. RESULTS: rs2241766 had no effects on circulating adiponectin levels or FMD. In subjects without CAD, carriers of the T/T alleles at rs1501299 had lower adiponectin levels (p=0.001) and impaired endothelial function (p<0.05). After multivariate adjustment none of the SNPs had any effect on CAD risk. However, carriers of the T allele at rs1501299 were at increased myocardial infarction (MI) risk, independently of classic risk factors (OR=2.558 [95%CI=1.587-4.123], p=0.0001). The number of T alleles in both SNPs was strongly associated with MI history (p=0.0001). CONCLUSIONS: rs1501299 polymorphism of adiponectin gene affects circulating adiponectin levels and endothelial function in subjects without CAD. Presence of the T variant at rs1501299 on adiponectin gene is independently associated with increased myocardial infarction risk.

Van-Assche T, Huygelen V, Crabtree MJ, Antoniades C. 2013. Gene delivery strategies targeting stable atheromatous plaque. Curr Pharm Des, 19 (9), pp. 1626-1637. | Show Abstract

Conventional therapeutic options to treat chronic angina pectoris are pharmacological interventions, coronary bypass surgery (CABG) and percutaneous coronary intervention (PCI). In animal models, it was shown that gene delivery strategies harbour an exciting potential to support and maybe even replace conventional anti-angina treatments, but the translation of the basic science to clinical practise appears problematic. Gene therapy targeting key elements of neointima formation (e.g. cell cycle regulators, metalloproteinases, inflammation and oxidative stress) reduces vein graft and stent failure in experimental models. Additionally, systemic gene delivery of genes targeting NO production, oxidative stress, inflammation and foam cell formation has been shown to prevent atherosclerosis in different animal models. During CABG the vein graft can be transfected ex vivo and during PCI, a stent carrying transfection vectors can be deployed. Both strategies result in the induction of local transgene expression at the site of interest. This limits unwarranted transgene expression and the toxicity seen with systemic gene delivery. However, with the development of new transfection vectors, able to induce local transgene expression without detrimental side effects, systemic anti-inflammatory and anti-oxidative, gene delivery could be a powerful tool in secondary prevention.

Tousoulis D, Vogiatzi G, Briasoulis A, Valatsou A, Nikolopoulou P, Papaxoinis K, Pantopoulou A, Papageorgiou N, Antoniades C, Perrea D, Stefanadis C. 2013. Improved limb perfusion and neoangiogenesis after intramuscular erythropoietin infusion in experimental model of limb ischemia. Int J Cardiol, 165 (1), pp. 195-197. | Read more

Michaelides AP, Liakos CI, Raftopoulos LG, Antoniades C, Tsiachris D, Marinou K, Stefanadis CI. 2012. Correlation of arm position and exercise test interpretation. Hellenic J Cardiol, 53 (5), pp. 397-399. | Show Abstract

ST-segment changes during exercise testing can be attributed mainly to ischemia, but also, in some patients, to other physiological parameters, such as body position or hyperventilation, making ECG exercise test interpretation more complex. Here we describe the case of a patient who had an electrocardiographically positive exercise test, in order to illustrate the correlation between arm position and ST changes during exercise testing.

Marinou K, Christodoulides C, Antoniades C, Koutsilieris M. 2012. Wnt signaling in cardiovascular physiology. Trends Endocrinol Metab, 23 (12), pp. 628-636. | Show Abstract | Read more

Wnt signaling pathways play a key role in cardiac development, angiogenesis, and cardiac hypertrophy; emerging evidence suggests that they are also involved in the pathophysiology of atherosclerosis. Specifically, an important role for Wnts has been described in the regulation of endothelial inflammation, vascular calcification, and mesenchymal stem cell differentiation. Wnt signaling also induces monocyte adhesion to endothelial cells and is crucial for the regulation of vascular smooth-muscle cell (VSMC) behavior. We discuss how the Wnt pathways are implicated in vascular biology and outline the role of Wnt signaling in atherosclerosis. Dissecting Wnt pathways involved in atherogenesis and cardiovascular disease may provide crucial insights into novel mechanisms with therapeutic potential for atherosclerosis.

Antonopoulos AS, Margaritis M, Shirodaria C, Antoniades C. 2012. Translating the effects of statins: from redox regulation to suppression of vascular wall inflammation. Thromb Haemost, 108 (5), pp. 840-848. | Show Abstract | Read more

Vascular oxidative stress is a key feature of atherogenesis, and targeting vascular redox signalling is a rational therapeutic goal in vascular disease pathogenesis. 3-hydroxy-3-methyl-glutaryl-CoA reductase inhibitors or statins are potent lipid-lowering drugs that improve cardiovascular outcomes. It is now widely accepted that cardiovascular disease prevention by statins is dependent not only on their lipid lowering effects, but also on their beneficial effects on vascular redox signalling. Cell culture and animal models have provided important findings on the effects of statins on vascular redox and nitric oxide bioavailability. Recent evidence from studies on human vessels has further enhanced our understanding of the "pleiotropic" effects of statins on vascular wall. Reversal of endothelial dysfunction in human vessels by statins is dependent on the mevalonate pathway and Rac1 inhibition. These critical steps are responsible for reducing NADPH-oxidase activity and improving tetrahydrobiopterin bioavailability and nitric oxide synthase (NOS) coupling in human vessels. However, mevalonate pathway inhibition has been also held responsible for some of the side effects observed after statin treatment. In this review we summarise the existing knowledge on the effects of statins on vascular biology by discussing key findings from basic science as well as recent evidence from translational studies in humans. Finally, we discuss emerging aspects of statin pleiotropy, such as their effects on adipose tissue biology and adipokine synthesis that may light additional mechanistic links between statin treatment and improvement of clinical outcome in primary and secondary prevention.

Lee R, Adlam D, Antoniades C, Digby JE, Kharbanda RK, Choudhury RP, Channon KM. 2013. Heparin administration leads to rapid decrease in plasma matrix metalloproteinase-9. Int J Cardiol, 163 (2), pp. 212-213. | Read more

Psarros C, Lee R, Margaritis M, Antoniades C. 2012. Nanomedicine for the prevention, treatment and imaging of atherosclerosis. Nanomedicine, 8 Suppl 1 (1), pp. S59-S68. | Show Abstract | Read more

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in developed countries, with an increasing prevalence due to an aging population. The pathology underpinning CVD is atherosclerosis, a chronic inflammatory state involving the arterial wall. Accumulation of low density lipoprotein (LDL) laden macrophages in the arterial wall and their subsequent transformation into foam cells lead to atherosclerotic plaque formation. Progression of atherosclerotic lesions may gradually lead to plaque related complications and clinically manifest as acute vascular syndromes including acute myocardial or cerebral ischemia. Nanotechnology offers emerging therapeutic strategies, which may have advantage overclassical treatments for atherosclerosis. In this review, we present the potential applications of nanotechnology toward prevention, identification and treatment of atherosclerosis.

Tousoulis D, Kampoli AM, Papageorgiou N, Antoniades C, Siasos G, Latsios G, Tsiamis E, Stefanadis C. 2012. Matrix metallopropteinases in heart failure. Curr Top Med Chem, 12 (10), pp. 1181-1191. | Show Abstract | Read more

Heart failure (HF) represents a complex multifactorial syndrome, characterized by crucial structural and functional abnormalities of the myocardium. Matrix metalloproteinases are associated with left ventricular dysfunction, adverse left ventricular remodelling and prognosis after acute myocardial infarction. There is a strong association between oxidative stress and MMPs in the pathophysiology of HF. As MMPs are strongly associated to the pathogenesis and pathophysiology of HF, several agents have been proposed as potential modulators of these molecules. Classical agents such as statins, angiotensin converting enzyme inhibitors (ACEIS) and beta-blockers and a variety of novel agents have been implicated in the pathogenesis and progression of heart failure via the matrix metalloproteinases pathway and consist of possible future therapeutic targets.

Briasoulis A, Tousoulis D, Papageorgiou N, Kampoli AM, Androulakis E, Antoniades C, Tsiamis E, Latsios G, Stefanadis C. 2012. Novel therapeutic approaches targeting matrix metalloproteinases in cardiovascular disease. Curr Top Med Chem, 12 (10), pp. 1214-1221. | Show Abstract | Read more

Matrix metalloproteinases (MMPs), are proteinases that participate in extracellular matrix remodelling and degradation. Under normal physiological conditions, the activities of MMPs are regulated at the level of transcription, of activation of the pro-MMP precursor zymogens and of inhibition by endogenous inhibitors (tissue inhibitors of metalloproteinases; TIMPs). Alteration in the regulation of MMP activity is implicated in atherosclerotic plaque development, coronary artery disease and heart failure. The pathological effects of MMPs and TIMPs in cardiovascular diseases involve vascular remodelling, atherosclerotic plaque instability and left ventricular remodelling after myocardial infarction. Since excessive tissue remodelling and increased matrix metalloproteinase activity have been demonstrated during atherosclerotic lesion progression, MMPs represent a potential target for therapeutic intervention aimed at modification of vascular pathology by restoring the physiological balance between MMPs and TIMPs. This review discusses pharmacological approaches to MMP inhibition.

Kampoli AM, Tousoulis D, Papageorgiou N, Antoniades C, Androulakis E, Tsiamis E, Latsios G, Stefanadis C. 2012. Matrix metalloproteinases in acute coronary syndromes: current perspectives. Curr Top Med Chem, 12 (10), pp. 1192-1205. | Show Abstract | Read more

Matrix metalloproteinases (MMPs) are a family of zinc metallo-endopeptidases secreted by cells and are responsible for much of the turnover of matrix components. Several studies have shown that MMPs are involved in all stages of the atherosclerotic process, from the initial lesion to plaque rupture. Recent evidence suggests that MMP activity may facilitate atherosclerosis, plaque destabilization, and platelet aggregation. In the heart, matrix metalloproteinases participate in vascular remodeling, plaque instability, and ventricular remodelling after cardiac injury. The aim of the present article is to review the structure, function, regulation of MMPs and to discuss their potential role in the pathogenesis of acute coronary syndromes, as well as their contribution and usefullness in the setting of the disease.

Bakogiannis C, Tousoulis D, Androulakis E, Briasoulis A, Papageorgiou N, Vogiatzi G, Kampoli AM, Charakida M, Siasos G, Latsios G et al. 2012. Circulating endothelial progenitor cells as biomarkers for prediction of cardiovascular outcomes. Curr Med Chem, 19 (16), pp. 2597-2604. | Show Abstract | Read more

Experimental studies suggest that bone marrow-derived endothelial progenitor cells (EPCs) play an important role in the maintenance of endothelial integrity and hemostasis. The number of circulating EPC has been shown to be inversely correlated with cardiovascular risk factors and vascular function and to predict cardiovascular events independent of both traditional and non-traditional risk factors. Thus, EPCs provide a clinical advantage over the use of other biomarkers as their measurement is directly associated with endothelial function, and available evidence suggests that they are consistently and significantly associated with a spectrum of cardiovascular complications, such as acute coronary syndromes and coronary artery disease. However, many issues in the field of EPC isolation and identification, particularly in regards to the effective and unequivocal molecular characterization of these cells still remain unresolved. In addition, simple EPC counts do not adequately describe cardiovascular disease risk. This limitation is attributable to variation in the definition of EPCs, the number of existing cardiovascular risk factors in different patients as well as a difference in the interaction between EPCs and other hematopoietic progenitor, inflammatory cells or platelets.

Tousoulis D, Hatzis G, Papageorgiou N, Androulakis E, Bouras G, Giolis A, Bakogiannis C, Siasos G, Latsios G, Antoniades C, Stefanadis C. 2012. Assessment of acute coronary syndromes: focus on novel biomarkers. Curr Med Chem, 19 (16), pp. 2572-2587. | Show Abstract | Read more

Coronary artery disease (CAD) is the leading cause of mortality in Western Societies and several developing countries. Recent evidence suggests that most detrimental clinical manifestations of CAD, such as acute coronary syndromes (ACS), are the outcome of inflammatory processes that lead to plaque formation and rupture and eventually to ischemia and potentially myocardial necrosis. Neither of the traditionally used biomarkers is thought to be the gold standard in detection of myocardial ischemia or necrosis. A biomarker that could detect quite early the ischemic myocardium as well as define the risk of a future event with high sensitivity and specificity is still lacking. Several biomarkers, implicated in the pathogenesis and clinical evolution of atherosclerosis, have emerged as potent biomarkers for early detection of myocardial ischemia. In the current review, we summarize recent evidence of the most promising biomarkers and discuss their potential role in clinical practice in patients suffering from ACSs.

Lee R, Margaritis M, Channon KM, Antoniades C. 2012. Evaluating oxidative stress in human cardiovascular disease: methodological aspects and considerations. Curr Med Chem, 19 (16), pp. 2504-2520. | Show Abstract | Read more

Oxidative stress is a key feature in atherogenesis, since reactive oxygen species (ROS) are involved in all stages of the disease, from endothelial dysfunction to atheromatic plaque formation and rupture. It is therefore important to identify reliable biomarkers allowing us to monitor vascular oxidative stress status. These may lead to improved understanding of disease pathogenesis and development of new therapeutic strategies. Measurement of circulating biomarkers of oxidative stress is challenging, since circulation usually behaves as a separate compartment to the individual structures of the vascular wall. However, measurement of stable products released by the reaction of ROS and vascular/circulating molecular structures is a particularly popular approach. Serum lipid hydroperoxides, plasma malondialdehyde or urine F2-isoprostanes are widely used and have a prognostic value in cardiovascular disease. Quantification of oxidative stress at a tissue level is much more accurate. Various chemiluminescence and high performance liquid chromatography assays have been developed over the last few years, and some of them are extremely accurate and specific. Electron spin resonance spectroscopy and micro-electrode assays able to detect ROS directly are also widely used. In conclusion, measurement of circulating biomarkers of oxidative stress is valuable, and some of them appear to have predictive value in cardiovascular disease. However, these biomarkers do not necessarily reflect intravascular oxidative stress and therefore cannot be used as therapeutic targets or markers to monitor pharmacological treatments in clinical settings. Measurement of vascular oxidative stress status is still the only reliable way to evaluate the involvement of oxidative stress in atherogenesis.

Tousoulis D, Antoniades C, Vlachopoulos C, Stefanadis C. 2013. Flow mediated dilation and carotid intima media thickness: clinical markers or just research tools? Int J Cardiol, 163 (3), pp. 226-228. | Read more

Antonopoulos AS, Margaritis M, Lee R, Channon K, Antoniades C. 2012. Statins as anti-inflammatory agents in atherogenesis: molecular mechanisms and lessons from the recent clinical trials. Curr Pharm Des, 18 (11), pp. 1519-1530. | Show Abstract | Read more

Ample evidence exists in support of the potent anti-inflammatory properties of statins. In cell studies and animal models statins exert beneficial cardiovascular effects. By inhibiting intracellular isoprenoids formation, statins suppress vascular and myocardial inflammation, favorably modulate vascular and myocardial redox state and improve nitric oxide bioavailability. Randomized clinical trials have demonstrated that further to their lipid lowering effects, statins are useful in the primary and secondary prevention of coronary heart disease (CHD) due to their anti-inflammatory potential. The landmark JUPITER trial suggested that in subjects without CHD, suppression of low-grade inflammation by statins improves clinical outcome. However, recent trials have failed to document any clinical benefit with statins in high risk groups, such in heart failure or chronic kidney disease patients. In this review, we aim to summarize the existing evidence on statins as an anti-inflammatory agent in atherogenesis. We describe the molecular mechanisms responsible for the antiinflammatory effects of statins, as well as clinical data on the non lipid-lowering, anti-inflammatory effects of statins on cardiovascular outcomes. Lastly, the controversy of the recent large randomized clinical trials and the issue of statin withdrawal are also discussed.

Margaritis M, Channon KM, Antoniades C. 2012. Statins and vein graft failure in coronary bypass surgery. Curr Opin Pharmacol, 12 (2), pp. 172-180. | Show Abstract | Read more

Saphenous vein grafts used in coronary artery bypass graft surgery suffer from lower patency rates compared to left internal mammary artery. A number of clinical trials and observational studies have demonstrated a significant benefit of statin treatment on vein graft patency. Aside from their well-known lipid-lowering capacities, statins exert pleiotropic effects by direct inhibition of the mevalonate pathway in the wall of these grafts. This leads to reduced geranylgeranylation of small GTPases such as Rho and Rac. Through this LDL-independent mechanism, statins improve endothelial function and reduce vascular inflammation and oxidative stress, inhibiting also smooth muscle cell proliferation and migration. Although the existing evidence supports a beneficial effect of statins on vein grafts biology, more clinical trials focused on the effect of aggressive statin treatment on vein graft patency are required, in order to safely translate this strategy into clinical practice.

Cunnington C, Van Assche T, Shirodaria C, Kylintireas I, Lindsay AC, Lee JM, Antoniades C, Margaritis M, Lee R, Cerrato R et al. 2012. Systemic and vascular oxidation limits the efficacy of oral tetrahydrobiopterin treatment in patients with coronary artery disease. Circulation, 125 (11), pp. 1356-1366. | Show Abstract | Read more

BACKGROUND: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) plays a pivotal role in maintaining endothelial function in experimental vascular disease models and in humans. Augmentation of endogenous BH4 levels by oral BH4 treatment has been proposed as a potential therapeutic strategy in vascular disease states. We sought to determine the mechanisms relating exogenous BH4 to human vascular function and to determine oral BH4 pharmacokinetics in both plasma and vascular tissue in patients with coronary artery disease. METHODS AND RESULTS: Forty-nine patients with coronary artery disease were randomized to receive low-dose (400 mg/d) or high-dose (700 mg/d) BH4 or placebo for 2 to 6 weeks before coronary artery bypass surgery. Vascular function was quantified by magnetic resonance imaging before and after treatment, along with plasma BH4 levels. Vascular superoxide, endothelial function, and BH4 levels were determined in segments of saphenous vein and internal mammary artery. Oral BH4 treatment significantly augmented BH4 levels in plasma and in saphenous vein (but not internal mammary artery) but also increased levels of the oxidation product dihydrobiopterin (BH2), which lacks endothelial nitric oxide synthase cofactor activity. There was no effect of BH4 treatment on vascular function or superoxide production. Supplementation of human vessels and blood with BH4 ex vivo revealed rapid oxidation of BH4 to BH2 with predominant BH2 uptake by vascular tissue. CONCLUSIONS: Oral BH4 treatment augments total biopterin levels in patients with established coronary artery disease but has no net effect on vascular redox state or endothelial function owing to systemic and vascular oxidation of BH4. Alternative strategies are required to target BH4-dependent endothelial function in established vascular disease states.

Psarros C, Lee R, Margaritis M, Antoniades C. 2012. Nanomedicine for the prevention, treatment and imaging of atherosclerosis. Maturitas, 73 (1), pp. 52-60. | Show Abstract | Read more

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in developed countries, with an increasing prevalence due to an aging population. The pathology underpinning CVD is atherosclerosis, a chronic inflammatory state involving the arterial wall. Accumulation of low density lipoprotein (LDL) laden macrophages in the arterial wall and their subsequent transformation into foam cells lead to atherosclerotic plaque formation. Progression of atherosclerotic lesions may gradually lead to plaque related complications and clinically manifest as acute vascular syndromes including acute myocardial or cerebral ischemia. Nanotechnology offers emerging therapeutic strategies, which may have advantage overclassical treatments for atherosclerosis. In this review, we present the potential applications of nanotechnology toward prevention, identification and treatment of atherosclerosis.

Antoniades C, Demosthenous M, Reilly S, Margaritis M, Zhang MH, Antonopoulos A, Marinou K, Nahar K, Jayaram R, Tousoulis D et al. 2012. Myocardial redox state predicts in-hospital clinical outcome after cardiac surgery effects of short-term pre-operative statin treatment. J Am Coll Cardiol, 59 (1), pp. 60-70. | Show Abstract | Read more

OBJECTIVES: The purpose of this study was to evaluate the role of the myocardial redox state in the development of in-hospital complications after cardiac surgery and the effect of statins on the myocardial redox state. BACKGROUND: Statins improve clinical outcome after cardiac surgery, but it is unclear whether they exert their effects by modifying the myocardial redox state. METHODS: We quantified myocardial superoxide anion (O(2)(-)) and peroxynitrite (ONOO(-)) and their enzymatic sources in samples of the right atrial appendage (RAA) from 303 patients undergoing cardiac surgery who were followed up until discharge, and in 42 patients who were randomized to receive 3-day treatment with atorvastatin 40 mg/d or placebo before surgery. The mechanisms by which atorvastatin modifies myocardial redox state were investigated in 26 RAA samples that were exposed to atorvastatin ex vivo. RESULTS: Atrial O(2)(-) (derived mainly from nicotinamide adenine dinucleotide phosphate [NADPH] oxidases) and ONOO(-) were independently associated with increased risk of atrial fibrillation, the need for post-operative inotropic support, and the length of hospital stay. Pre-operative atorvastatin treatment suppressed atrial NADPH oxidase activity and myocardial O(2)(-) and ONOO(-) production. Ex vivo incubation of RAA samples with atorvastatin induced a mevalonate-reversible and Rac1-mediated inhibition of NADPH oxidase. CONCLUSIONS: There is a strong independent association between myocardial O(2)(-)/ONOO(-) and in-hospital complications after cardiac surgery. Both myocardial O(2)(-) and ONOO(-) are reduced by pre-operative statin treatment, through a Rac1-mediated suppression of NADPH oxidase activity. These findings suggest that inhibition of myocardial NADPH oxidases may contribute to the beneficial effect of statins in patients undergoing cardiac surgery. (Effects of Atorvastatin on Endothelial Function, Vascular and Myocardial Redox State in High Cardiovascular Risk Patients; NCT01013103).

Cited:

49

Scopus

Marinou K, Christodoulides C, Antoniades C, Koutsilieris M. 2012. Wnt signaling in cardiovascular physiology Trends in Endocrinology and Metabolism, 23 (12), pp. 628-636. | Show Abstract | Read more

Wnt signaling pathways play a key role in cardiac development, angiogenesis, and cardiac hypertrophy; emerging evidence suggests that they are also involved in the pathophysiology of atherosclerosis. Specifically, an important role for Wnts has been described in the regulation of endothelial inflammation, vascular calcification, and mesenchymal stem cell differentiation. Wnt signaling also induces monocyte adhesion to endothelial cells and is crucial for the regulation of vascular smooth-muscle cell (VSMC) behavior. We discuss how the Wnt pathways are implicated in vascular biology and outline the role of Wnt signaling in atherosclerosis. Dissecting Wnt pathways involved in atherogenesis and cardiovascular disease may provide crucial insights into novel mechanisms with therapeutic potential for atherosclerosis. © 2012 Elsevier Ltd.

Cerrato R, Cunnington C, Crabtree MJ, Antoniades C, Pernow J, Channon KM, Bohm F. 2012. Endothelin-1 increases superoxide production in human coronary artery bypass grafts LIFE SCIENCES, 91 (13-14), pp. 723-728. | Show Abstract | Read more

Aims: Endothelin-1 (ET-1) has been shown to increase endothelial superoxide (O 2 - ) production in experimental animal models. It is unclear whether ET-1 increases O 2 - production in humans. We sought to elucidate whether ET-1 increases O 2 - production in human vessels and to identify the mechanism behind this effect. Main methods: Segments of internal mammary artery (IMA) and human saphenous vein (HSV) were harvested from 90 patients undergoing elective coronary artery bypass graft surgery. Paired vessel rings were incubated in the presence and absence of ET-1 (10 - 10 M), the ET A receptor antagonist BQ123 alone, or in combination with the ET B receptor antagonist BQ788 (dual BQ) and known inhibitors of sources of O 2 - and further analysed for O 2 - production using lucigenin-enhanced chemiluminescence and DHE fluorescence. Key findings: ET-1 increased O 2 - production in both IMA (2.6 ± 1.5 vs. 1.4 ± 0.8 relative light units/s/mg tissue (RLU); n = 33; p < 0.0001) and HSV (1.4 ± 0.8 vs. 1.1 ± 0.6 RLU; n = 24; p < 0.05). The increase in O 2 - production induced by ET-1 in IMA was inhibited by co-incubation with dual BQ (p < 0.05; n = 15) and BQ123 (p < 0.05; n = 17). Of known O 2 - inhibitors, only incubation with Tiron and diphenyleneiodonium resulted in a significant reduction in ET-mediated O 2 - production. Significance: ET-1 increases O 2 - production especially in human arteries and less so in veins from patients with coronary artery disease via a receptor-dependent pathway involving a flavin dependent enzyme which is likely to be NADPH oxidase. Production of O 2 - may be an important factor underlying the negative effects of ET-1 on vascular function such as impairment of endothelium-dependent vasodilatation and pro-inflammatory effects. © 2012 Elsevier Inc. All rights reserved.

Psarros C, Lee R, Margaritis M, Antoniades C. 2012. Nanomedicine for the prevention, treatment and imaging of atherosclerosis Nanomedicine: Nanotechnology, Biology, and Medicine, 8 (SUPPL. 1), | Show Abstract | Read more

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in developed countries, with an increasing prevalence due to an aging population. The pathology underpinning CVD is atherosclerosis, a chronic inflammatory state involving the arterial wall. Accumulation of low density lipoprotein (LDL) laden macrophages in the arterial wall and their subsequent transformation into foam cells lead to atherosclerotic plaque formation. Progression of atherosclerotic lesions may gradually lead to plaque related comp lications and clinically manifest as acute vascular syndromes including acute myocardial or cerebral ischemia. Nanotechnology offers emerging therapeutic strategies, which may have advantage overclassical treatments for atherosclerosis. In this review, we present the potential applications of nanotechnology toward prevention, identification and treatment of atherosclerosis. © 2012 Elsevier Inc.

Cited:

69

Scopus

Cunnington C, Van Assche T, Shirodaria C, Kylintireas I, Lindsay AC, Lee JM, Antoniades C, Margaritis M, Lee R, Cerrato R et al. 2012. Systemic and vascular oxidation limits the efficacy of oral tetrahydrobiopterin treatment in patients with coronary artery disease Circulation, 125 (11), pp. 1356-1366. | Show Abstract | Read more

BACKGROUND-: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) plays a pivotal role in maintaining endothelial function in experimental vascular disease models and in humans. Augmentation of endogenous BH4 levels by oral BH4 treatment has been proposed as a potential therapeutic strategy in vascular disease states. We sought to determine the mechanisms relating exogenous BH4 to human vascular function and to determine oral BH4 pharmacokinetics in both plasma and vascular tissue in patients with coronary artery disease. METHODS AND RESULTS-: Forty-nine patients with coronary artery disease were randomized to receive low-dose (400 mg/d) or high-dose (700 mg/d) BH4 or placebo for 2 to 6 weeks before coronary artery bypass surgery. Vascular function was quantified by magnetic resonance imaging before and after treatment, along with plasma BH4 levels. Vascular superoxide, endothelial function, and BH4 levels were determined in segments of saphenous vein and internal mammary artery. Oral BH4 treatment significantly augmented BH4 levels in plasma and in saphenous vein (but not internal mammary artery) but also increased levels of the oxidation product dihydrobiopterin (BH2), which lacks endothelial nitric oxide synthase cofactor activity. There was no effect of BH4 treatment on vascular function or superoxide production. Supplementation of human vessels and blood with BH4 ex vivo revealed rapid oxidation of BH4 to BH2 with predominant BH2 uptake by vascular tissue. CONCLUSIONS-: Oral BH4 treatment augments total biopterin levels in patients with established coronary artery disease but has no net effect on vascular redox state or endothelial function owing to systemic and vascular oxidation of BH4. Alternative strategies are required to target BH4-dependent endothelial function in established vascular disease states. © 2012 American Heart Association, Inc.

Margaritis M, Channon KM, Antoniades C. 2012. Statins and vein graft failure in coronary bypass surgery Current Opinion in Pharmacology, 12 (2), pp. 172-180. | Show Abstract | Read more

Saphenous vein grafts used in coronary artery bypass graft surgery suffer from lower patency rates compared to left internal mammary artery. A number of clinical trials and observational studies have demonstrated a significant benefit of statin treatment on vein graft patency. Aside from their well-known lipid-lowering capacities, statins exert pleiotropic effects by direct inhibition of the mevalonate pathway in the wall of these grafts. This leads to reduced geranylgeranylation of small GTPases such as Rho and Rac. Through this LDL-independent mechanism, statins improve endothelial function and reduce vascular inflammation and oxidative stress, inhibiting also smooth muscle cell proliferation and migration. Although the existing evidence supports a beneficial effect of statins on vein grafts biology, more clinical trials focused on the effect of aggressive statin treatment on vein graft patency are required, in order to safely translate this strategy into clinical practice. © 2012 Elsevier Ltd.

Brili S, Tousoulis D, Antonopoulos AS, Antoniades C, Hatzis G, Bakogiannis C, Papageorgiou N, Stefanadis C. 2012. Effects of atorvastatin on endothelial function and the expression of proinflammatory cytokines and adhesion molecules in young subjects with successfully repaired coarctation of aorta Heart, 98 (4), pp. 325-329. | Show Abstract | Read more

Objective: To investigate the effects of atorvastatin on endothelial function and low-grade systemic inflammation in subjects with successful surgery for aortic coarctation repair (SCR). Design: Open-label study. Setting: Outpatients visiting the adult congenital heart disease department of our hospital. Patients: 34 young people with SCR. Interventions: Patients with SCR received atorvastatin 10 mg/day (n=17) or no treatment (n=17) for 4 weeks. At baseline and at 4 weeks, endothelial function was assessed by flow-mediated dilatation (FMD) of the right brachial artery, and blood samples were obtained. Serum levels of interleukin (IL) 1b, IL-6 and soluble vascular cell adhesion molecule-1 (sVCAM-1) were determined by ELISA. Main outcome measures: Effects of treatment on FMD and serum levels of IL-1b, IL-6 and sVCAM-1. Results: FMD in the atorvastatin group was significantly improved after 4 weeks (from 6.4±60.95% to 11.24±1.38%, p < 0.01), while remaining unchanged in the control group (from 6.74±0.58% to 6.95±0.53%, p=NS). Even though atorvastatin had no effect on serum IL-6 levels (0.62 (0.37-0.88) pg/ml to 0.53 (0.28-0.73) pg/ml, p=NS), it significantly reduced circulating levels of IL-1b (from 1.17 (0.92-1.77) pg/ml to 1.02 (0.75-1.55) pg/ml, p±0.05) and sVCAM-1 (from 883.4 (660.3-1093.1) ng/ml to 801.4 (566.7-1030.2) ng/ml, p±0.05). No changes were seen in serum levels of IL-6, IL-1b and sVCAM-1 in the control group after 4 weeks compared with baseline (p=NS for all). Conclusions: Atorvastatin treatment for 4 weeks in subjects with SCR significantly improved endothelial function and suppressed systemic inflammatory status by decreasing circulating levels of IL-1b and sVCAM-1.

Margaritis M, Antoniades C. 2012. Statins in coronary artery bypass grafting surgery: lipid lowering and beyond. Expert Rev Cardiovasc Ther, 10 (1), pp. 5-8. | Read more

Cunnington C, Van Assche T, Shirodaria C, Kylintireas I, Lindsay AC, Lee JM, Antoniades C, Margaritis M, Lee R, Cerrato R et al. 2012. Systemic and vascular oxidation limits the efficacy of oral tetrahydrobiopterin treatment in patients with coronary artery disease Circulation, 125 (11), pp. 1356-1366.

Lee R, Antoniades C, Adlam D, Channon KM. 2012. Treatment of recurrent vein graft "stent-in-stent" re-stenosis guided by optical coherence tomography International Journal of Cardiology, 156 (1), | Read more

Lee R, Antoniades C. 2011. Thiobarbituric acid reactive substances as a biomarker for coronary heart disease. J Atheroscler Thromb, 18 (12), pp. 1127-1128. | Read more

Van-Assche T, Huygelen V, Crabtree MJ, Antoniades C. 2011. Gene therapy targeting inflammation in atherosclerosis. Curr Pharm Des, 17 (37), pp. 4210-4223. | Show Abstract | Read more

The extensive cross-talk between the immune system and vasculature leading to the infiltration of immune cells into the vascular wall is a major step in atherogenesis. In this process, reactive oxygen species play a crucial role, by inducing the oxidation of LDL and the formation of foam cells, and by activating a number of redox-sensitive transcriptional factors such as nuclear factor kappa B (NFkappa B) or activating protein 1 (AP1), that regulate the expression of multiple pro/anti inflammatory genes involved in atherogenesis. Delivery of genes encoding antioxidant defense enzymes (e.g. superoxide dismutase, catalase, glutathione peroxidase or heme oxygenase- 1) or endothelial nitric oxide synthase (eNOS), suppress atherogenesis in animal models. Similarly, delivery of genes encoding regulators of redox sensitive transcriptional factors (e.g. NF-kappa B, AP-1, Nrf2 etc) or reactive oxygen species scavengers have been successfully used in experimental studies. Despite the promising results from basic science, the clinical applicability of these strategies has proven to be particularly challenging. Issues regarding the vectors used to deliver the genes (and the development of immune responses or other side effects) and the inability of sufficient and sustained local expression of these genes at the target-tissue are some of the main reasons preventing optimism regarding the use of these strategies at a clinical level. Therefore, although premature to discuss about effective "gene therapy" in atherosclerosis at a clinical level, gene delivery techniques opened new horizons in cardiovascular research, and the development of new vectors may allow their extensive use in clinical trials in the future.

Tousoulis D, Kampoli AM, Papageorgiou N, Androulakis E, Antoniades C, Toutouzas K, Stefanadis C. 2011. Pathophysiology of atherosclerosis: the role of inflammation. Curr Pharm Des, 17 (37), pp. 4089-4110. | Show Abstract | Read more

Atherosclerosis is a disease of arteries and is characterized by endothelial dysfunction, vascular inflammation, and the build-up of lipids, cholesterol, calcium, and cellular debris within the intima of the vessel wall. A number of factors commonly characterized as "risk factors" for atherosclerosis have been identified to facilitate the development of atherosclerosis by decreasing NO bioavailability in the vascular endothelium. The serious clinical manifestations of atherosclerosis (including coronary heart disease, stroke, and peripheral vascular disease) augment the need of performing the appropriate diagnostic methods to the patients. The most important diagnostic methods include the usage of biochemical markers and the invasive and non-invasive imaging techniques assessing endothelial function. The main drug categories that have been proved to ameliorate the inflammatory state in atherosclerosis are angiotensin converting enzyme inhibitors/angiotensin receptors blockers, statins, and antioxidants.

Lee R, Channon KM, Antoniades C. 2012. Therapeutic strategies targeting endothelial function in humans: clinical implications. Curr Vasc Pharmacol, 10 (1), pp. 77-93. | Show Abstract | Read more

Persistent oxidative stress in the vascular wall may lead to endothelial dysfunction, a pathological process widely implicated in the morbidities observed in a spectrum of cardiovascular disease. The production of reactive oxygen species (ROS) is regulated by various oxidase enzymes and mitochondrial electron transport mechanisms. Nitric oxide (NO) is a key mediator of endothelial function via its effect on endothelium dependent vascular relaxation. Therapeutic interventions aimed to increase NO bioavailability in the vasculature may improve the long term cardiovascular outcome for healthy individuals, high-risk subjects, and patients with advanced atherosclerosis. Current therapeutic strategies focus on enhancing synthesis or lowering oxidative inactivation of NO in human vasculature. Of the available therapeutic agents, angiotensin converting enzyme inhibitors and statins have shown most promise at improving endothelial function and cardiovascular outcome after long term administration. Other therapeutic approaches may also be useful towards improving endothelial dysfunction. These strategies include targeting NO synthesis by modulation of endothelial nitric oxide synthase (eNOS) coupling, such as folates and tetrahydrobiopterin. Evidence for the benefits of gene therapy to improve endothelial function is also emerging. However, the long term direct clinical benefit of these strategies aimed to improve endothelial function still remains unclear.

Brili S, Tousoulis D, Antonopoulos AS, Antoniades C, Hatzis G, Bakogiannis C, Papageorgiou N, Stefanadis C. 2012. Effects of atorvastatin on endothelial function and the expression of proinflammatory cytokines and adhesion molecules in young subjects with successfully repaired coarctation of aorta. Heart, 98 (4), pp. 325-329. | Show Abstract | Read more

OBJECTIVE: To investigate the effects of atorvastatin on endothelial function and low-grade systemic inflammation in subjects with successful surgery for aortic coarctation repair (SCR). DESIGN: Open-label study. SETTING: Outpatients visiting the adult congenital heart disease department of our hospital. PATIENTS: 34 young people with SCR. INTERVENTIONS: Patients with SCR received atorvastatin 10 mg/day (n=17) or no treatment (n=17) for 4 weeks. At baseline and at 4 weeks, endothelial function was assessed by flow-mediated dilatation (FMD) of the right brachial artery, and blood samples were obtained. Serum levels of interleukin (IL) 1b, IL-6 and soluble vascular cell adhesion molecule-1 (sVCAM-1) were determined by ELISA. MAIN OUTCOME MEASURES: Effects of treatment on FMD and serum levels of IL-1b, IL-6 and sVCAM-1. RESULTS: FMD in the atorvastatin group was significantly improved after 4 weeks (from 6.46±0.95% to 11.24±1.38%, p<0.01), while remaining unchanged in the control group (from 6.74±0.58% to 6.95±0.53%, p=NS). Even though atorvastatin had no effect on serum IL-6 levels (0.62 (0.37-0.88) pg/ml to 0.53 (0.28-0.73) pg/ml, p=NS), it significantly reduced circulating levels of IL-1b (from 1.17 (0.92-1.77) pg/ml to 1.02 (0.75-1.55) pg/ml, p<0.05) and sVCAM-1 (from 883.4 (660.3-1093.1) ng/ml to 801.4 (566.7-1030.2) ng/ml, p<0.05). No changes were seen in serum levels of IL-6, IL-1b and sVCAM-1 in the control group after 4 weeks compared with baseline (p=NS for all). CONCLUSIONS: Atorvastatin treatment for 4 weeks in subjects with SCR significantly improved endothelial function and suppressed systemic inflammatory status by decreasing circulating levels of IL-1b and sVCAM-1.

Tousoulis D, Papageorgiou N, Androulakis E, Briasoulis A, Antoniades C, Stefanadis C. 2011. Fibrinogen and cardiovascular disease: genetics and biomarkers. Blood Rev, 25 (6), pp. 239-245. | Show Abstract | Read more

Several prospective epidemiological studies and clinical observations provided evidence regarding fibrinogen and coronary artery disease (CAD). Many of these studies firmly correlate fibrinogen with CAD. However, it is uncertain whether this relation is causal or reflects genetic variability and residual confounding by other risk factors. Several polymorphisms on fibrinogen chain genes affect its levels, however only few of the genetic variants are associated with increased cardiovascular risk. As regards the role of fibrinogen in myocardial infarction (MI) studies indicate that genetic variations have at best a modest impact on the process resulting in MI. Therefore, the screening of fibrinogen genes might not be useful for the assessment of the risk of MI. However, the findings that specific genotypes lead to specific differences in fibrinogen levels, but may not be linked to cardiovascular risk, complicates the hypothesis of causality of fibrinogen in the pathogenesis of cardiovascular disease.

Kardara D, Tousoulis D, Antoniades C, Koumallos N, Xaplanteris P, Kyvelou SM, Papageorgiou N, Vasiliadou C, Vlachopoulos C, Stefanadis C. 2011. Effects of the Ala379Val polymorphism of lipoprotein-associated phospholipase A2 on thrombosis and inflammation in hypertensive patients. Int J Cardiol, 152 (2), pp. 247-249. | Read more

Tousoulis D, Papageorgiou N, Latsios G, Siasos G, Antoniades C, Stefanadis C. 2011. C-reactive protein and endothelial dysfunction: gazing at the coronaries. Int J Cardiol, 152 (1), pp. 1-3. | Read more

Tousoulis D, Andreou I, Antoniades C, Siasos G, Stougiannos P, Trikas A, Stefanadis C. 2011. Do endothelial progenitor cells modify our strategy to treat risk factors? Int J Cardiol, 152 (1), pp. 95-97. | Read more

Antoniades C, Cunnington C, Antonopoulos A, Neville M, Margaritis M, Demosthenous M, Bendall J, Hale A, Cerrato R, Tousoulis D et al. 2011. Induction of vascular GTP-cyclohydrolase I and endogenous tetrahydrobiopterin synthesis protect against inflammation-induced endothelial dysfunction in human atherosclerosis. Circulation, 124 (17), pp. 1860-1870. | Show Abstract | Read more

BACKGROUND: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) is essential for maintenance of enzymatic function. We hypothesized that induction of BH4 synthesis might be an endothelial defense mechanism against inflammation in vascular disease states. METHODS AND RESULTS: In Study 1, 20 healthy individuals were randomized to receive Salmonella typhi vaccine (a model of acute inflammation) or placebo in a double-blind study. Vaccination increased circulating BH4 and interleukin 6 and induced endothelial dysfunction (as evaluated by brachial artery flow-mediated dilation) after 8 hours. In Study 2, a functional haplotype (X haplotype) in the GCH1 gene, encoding GTP-cyclohydrolase I, the rate-limiting enzyme in biopterin biosynthesis, was associated with endothelial dysfunction in the presence of high-sensitivity C-reactive protein in 440 coronary artery disease patients. In Study 3, 10 patients with coronary artery disease homozygotes for the GCH1 X haplotype (XX) and 40 without the haplotype (OO) underwent S Typhi vaccination. XX patients were unable to increase plasma BH4 and had a greater reduction of flow-mediated dilation than OO patients. In Study 4, vessel segments from 19 patients undergoing coronary bypass surgery were incubated with or without cytokines (interleukin-6/tumor necrosis factor-α/lipopolysaccharide) for 24 hours. Cytokine stimulation upregulated GCH1 expression, increased vascular BH4, and improved vasorelaxation in response to acetylcholine, which was inhibited by the GTP-cyclohydrolase inhibitor 2,4-diamino-6-hydroxypyrimidine. CONCLUSIONS: The ability to increase vascular GCH1 expression and BH4 synthesis in response to inflammation preserves endothelial function in inflammatory states. These novel findings identify BH4 as a vascular defense mechanism against inflammation-induced endothelial dysfunction.

Lim CC, Cuculi F, van Gaal WJ, Testa L, Arnold JR, Karamitsos T, Francis JM, Digby JE, Antoniades C, Kharbanda RK et al. 2011. Early diagnosis of perioperative myocardial infarction after coronary bypass grafting: a study using biomarkers and cardiac magnetic resonance imaging. Ann Thorac Surg, 92 (6), pp. 2046-2053. | Show Abstract | Read more

BACKGROUND: Myocardial injury related to coronary artery bypass grafting (CABG) is poorly characterized, and understanding the characteristic release of biomarkers associated with revascularization injury might provide novel therapeutic opportunities. This study characterized early changes in biomarkers after revascularization injury during on-pump CABG. METHODS: This prospective study comprised 28 patients undergoing on-pump CABG and late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMRI) who underwent measurements of cardiac troponin I (cTnI), creatine kinase-MB, and inflammatory markers (C-reactive protein, serum amyloid A, myeloperoxidase, interleukin 6, tumor necrosis factor-α, matrix metalloproteinase 9a, monocyte chemotactic protein-1, plasminogen activator inhibitor-1a) at baseline, at 1, 6, 12, and 24 hours, and at 1 week (inflammatory markers only) post-CABG. Biomarker results at 1 hour were studied for a relationship to new myocardial infarction as defined by CMRI-LGE, and the diagnostic utility of combining positive biomarkers was assessed. RESULTS: All patients had an uneventful recovery, but 9 showed a new myocardial infarction demonstrated by new areas of hyperenhancement on CMR. Peak cTnI at 24 hours (ρ = 0.66, p < 0.001) and CK-MB (ρ = 0.66, p < 0.001) correlated with the amount of new LGE. At 1 hour, 3 biomarkers--cTnI, interleukin 6, and tumor necrosis factor-α--were significantly elevated in patients with vs those without new LGE. Receiver operating curve analysis showed cTnI was the most accurate at detecting new LGE at 1 hour: a cutoff of cTnI exceeding 5 μg/L at 1 hour had 67% sensitivity and 79% specificity for detecting new LGE. CONCLUSIONS: Unexpected CABG-related myocardial injury occurs in a significant proportion of patients. A cTnI test at 1 hour after CABG could potentially differentiate patients with significant revascularization injury.

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Reilly SN, Jayaram R, Nahar K, Antoniades C, Verheule S, Channon KM, Alp NJ, Schotten U, Casadei B. 2011. Atrial Sources of Reactive Oxygen Species Vary With the Duration and Substrate of Atrial Fibrillation Implications for the Antiarrhythmic Effect of Statins CIRCULATION, 124 (10), pp. 1107-1U91. | Show Abstract | Read more

BACKGROUND-: An altered nitric oxide-redox balance has been implicated in the pathogenesis of atrial fibrillation (AF). Statins inhibit NOX2-NADPH oxidases and prevent postoperative AF but are less effective in AF secondary prevention; the mechanisms underlying these findings are poorly understood. METHODS AND RESULTS-: By using goat models of pacing-induced AF or of atrial structural remodeling secondary to atrioventricular block and right atrial samples from 130 patients undergoing cardiac surgery, we found that the mechanisms responsible for the NO-redox imbalance differ between atria and with the duration and substrate of AF. Rac1 and NADPH oxidase activity and the protein level of NOX2 and p22phox were significantly increased in the left atrium of goats after 2 weeks of AF and in patients who developed p ostoperative AF in the absence of differences in leukocytes infiltration. Conversely, in the presence of longstanding AF or atrioventricular block, uncoupled nitric oxide synthase activity (secondary to reduced BH4 content and/or increased arginase activity) and mitochondrial oxidases accounted for the biatrial increase in reactive oxygen species. Atorvastatin caused a mevalonate-reversible inhibition of Rac1 and NOX2-NADPH oxidase activity in right atrial samples from patients who developed postoperative AF, but it did not affect reactive oxygen species, nitric oxide synthase uncoupling, or BH4 in patients with permanent AF. CONCLUSIONS-: Upregulation of atrial NADPH oxidases is an early but transient event in the natural history of AF. Changes in the sources of reactive oxygen species with atrial remodeling may explain why statins are effective in the primary prevention of AF but not in its management. © 2011 American Heart Association, Inc.

Reilly SN, Jayaram R, Nahar K, Antoniades C, Verheule S, Channon KM, Alp NJ, Schotten U, Casadei B. 2011. Atrial sources of reactive oxygen species vary with the duration and substrate of atrial fibrillation: implications for the antiarrhythmic effect of statins. Circulation, 124 (10), pp. 1107-1117. | Show Abstract | Read more

BACKGROUND: An altered nitric oxide-redox balance has been implicated in the pathogenesis of atrial fibrillation (AF). Statins inhibit NOX2-NADPH oxidases and prevent postoperative AF but are less effective in AF secondary prevention; the mechanisms underlying these findings are poorly understood. METHODS AND RESULTS: By using goat models of pacing-induced AF or of atrial structural remodeling secondary to atrioventricular block and right atrial samples from 130 patients undergoing cardiac surgery, we found that the mechanisms responsible for the NO-redox imbalance differ between atria and with the duration and substrate of AF. Rac1 and NADPH oxidase activity and the protein level of NOX2 and p22phox were significantly increased in the left atrium of goats after 2 weeks of AF and in patients who developed postoperative AF in the absence of differences in leukocytes infiltration. Conversely, in the presence of longstanding AF or atrioventricular block, uncoupled nitric oxide synthase activity (secondary to reduced BH4 content and/or increased arginase activity) and mitochondrial oxidases accounted for the biatrial increase in reactive oxygen species. Atorvastatin caused a mevalonate-reversible inhibition of Rac1 and NOX2-NADPH oxidase activity in right atrial samples from patients who developed postoperative AF, but it did not affect reactive oxygen species, nitric oxide synthase uncoupling, or BH4 in patients with permanent AF. CONCLUSIONS: Upregulation of atrial NADPH oxidases is an early but transient event in the natural history of AF. Changes in the sources of reactive oxygen species with atrial remodeling may explain why statins are effective in the primary prevention of AF but not in its management.

Tousoulis D, Bouras G, Antoniades C, Marinou K, Papageorgiou N, Miliou A, Hatzis G, Stefanadi E, Tsioufis C, Stefanadis C. 2011. Methionine-induced homocysteinemia impairs endothelial function in hypertensives: the role of asymmetrical dimethylarginine and antioxidant vitamins. Am J Hypertens, 24 (8), pp. 936-942. | Show Abstract | Read more

BACKGROUND: Nitric oxide synthase (NOS) inhibitor asymmetrical dimethylarginine (ADMA) is synthesized by the methylation of arginine as part of the methionine/homocysteine cycle. However, the mechanisms regulating ADMA synthesis in hypertension are unclear. METHODS: We investigated the role of ADMA and antioxidants in endothelial dysfunction during methionine-induced homocysteinemia in hypertensives. Thirty-nine hypertensives and forty-nine normotensive controls underwent methionine loading (100 mg methionine/kg BW), after being randomized to receive vitamin C (2 g) and E (800 IU) or placebo. Endothelium-dependent dilation (EDD) was evaluated by plethysmography (baseline and 4-h post-methionine loading (4-h PML)). RESULTS: Hypertensives had higher homocysteine at baseline (P < 0.001) and 4-h PML (P < 0.05), whereas methionine increased homocysteine in all groups. EDD was decreased in both vitamins and placebo groups in controls (P < 0.01 for both) and vitamins- and placebo-treated hypertensives (P < 0.05 and P < 0.01, respectively). In controls, ADMA was increased in both vitamin- and placebo groups (P < 0.01 for both) at 4-h PML. Hypertensives had higher ADMA at baseline (P < 0.01 vs. normotensive) and remained unchanged at 4-h PML (P = NS in placebo and vitamins treated). CONCLUSIONS: ADMA is elevated in hypertensives but remains unchanged after methionine loading, suggesting that ADMA plays an important role in endothelial dysfunction in hypertensives, but it is not responsible for homocysteine-induced endothelial dysfunction in these patients.

Antoniades C, Bakogiannis C, Leeson P, Guzik TJ, Zhang MH, Tousoulis D, Antonopoulos AS, Demosthenous M, Marinou K, Hale A et al. 2011. Rapid, direct effects of statin treatment on arterial redox state and nitric oxide bioavailability in human atherosclerosis via tetrahydrobiopterin-mediated endothelial nitric oxide synthase coupling. Circulation, 124 (3), pp. 335-345. | Show Abstract | Read more

BACKGROUND: Treatment with statins improves clinical outcome, but the exact mechanisms of pleiotropic statin effects on vascular function in human atherosclerosis remain unclear. We examined the direct effects of atorvastatin on tetrahydrobiopterin-mediated endothelial nitric oxide (NO) synthase coupling in patients with coronary artery disease. METHODS AND RESULTS: We first examined the association of statin treatment with vascular NO bioavailability and arterial superoxide (O(2)(·-)) in 492 patients undergoing coronary artery bypass graft surgery. Then, 42 statin-naïve patients undergoing elective coronary artery bypass graft surgery were randomized to atorvastatin 40 mg/d or placebo for 3 days before surgery to examine the impact of atorvastatin on endothelial function and O(2)(·-) generation in internal mammary arteries. Finally, segments of internal mammary arteries from 26 patients were used in ex vivo experiments to evaluate the statin-dependent mechanisms regulating the vascular redox state. Statin treatment was associated with improved vascular NO bioavailability and reduced O(2)(·-) generation in internal mammary arteries. Oral atorvastatin increased vascular tetrahydrobiopterin bioavailability and reduced basal and N-nitro-l-arginine methyl ester-inhibitable O(2)(·-) in internal mammary arteries independently of low-density lipoprotein lowering. In ex vivo experiments, atorvastatin rapidly improved vascular tetrahydrobiopterin bioavailability by upregulating GTP-cyclohydrolase I gene expression and activity, resulting in improved endothelial NO synthase coupling and reduced vascular O(2)(·-). These effects were reversed by mevalonate, indicating a direct effect of vascular hydroxymethylglutaryl-coenzyme A reductase inhibition. CONCLUSIONS: This study demonstrates for the first time in humans the direct effects of statin treatment on the vascular wall, supporting the notion that this effect is independent of low-density lipoprotein lowering. Atorvastatin directly improves vascular NO bioavailability and reduces vascular O(2)(·-) through tetrahydrobiopterin-mediated endothelial NO synthase coupling. These findings provide new insights into the mechanisms mediating the beneficial vascular effects of statins in humans. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01013103.

Adlam D, Antoniades C, Lee R, Diesch J, Shirodaria C, Taggart D, Leeson P, Channon KM. 2011. OCT characteristics of saphenous vein graft atherosclerosis. JACC Cardiovasc Imaging, 4 (7), pp. 807-809. | Read more

Antoniades C, Demosthenous M, Tousoulis D, Antonopoulos AS, Vlachopoulos C, Toutouza M, Marinou K, Bakogiannis C, Mavragani K, Lazaros G et al. 2011. Role of asymmetrical dimethylarginine in inflammation-induced endothelial dysfunction in human atherosclerosis. Hypertension, 58 (1), pp. 93-98. | Show Abstract | Read more

We explored the role of asymmetrical dimethylarginine (ADMA) as a cause of endothelial dysfunction induced by systemic inflammation. In vitro data suggest that ADMA bioavailability is regulated by proinflammatory stimuli, but it is unclear whether ADMA is a link between inflammation and endothelial dysfunction in humans. In study 1 we recruited 351 patients with coronary artery disease (CAD) and 87 healthy controls. In study 2 we recruited 69 CAD, 69 healthy, and 10 patients with rheumatoid arthritis, whereas in study 3, 22 healthy and 70 CAD subjects were randomly assigned to Salmonella typhii vaccination (n=11 healthy and n=60 CAD) or placebo (n=11 healthy and n=10 CAD). Circulating interleukin 6/ADMA and flow-mediated dilation (FMD) were measured at 0 and 8 hours. In study 1, ADMA was inversely correlated with FMD in healthy individuals and CAD patients (P<0.0001 for both). However, interleukin 6 was inversely correlated with FMD (P<0.0001) in healthy subjects but not in CAD patients. The positive correlation between ADMA and interleukin 6 was stronger in healthy (r=0.515; P<0.0001) compared with CAD (r=0.289; P=0.0001) subjects. In study 2, both patients with rheumatoid arthritis and CAD had higher interleukin 6 (P<0.0001) and ADMA (P=0.004) but lower FMD (P=0.001) versus healthy subjects. In study 3, vaccination increased interleukin 6 in healthy (P<0.001) and CAD (P<0.001) subjects. FMD was reduced in healthy subjects (P<0.05), but its reduction in CAD was borderline. Vaccination increased ADMA only in healthy subjects (P<0.001). Systemic, low-grade inflammation leads to increased ADMA that may induce endothelial dysfunction. This study demonstrated that ADMA may be a link between inflammation and endothelial dysfunction in humans.

Tousoulis D, Koniari K, Antoniades C, Papageorgiou N, Miliou A, Noutsou M, Nikolopoulou A, Marinou K, Stefanadi E, Siasos G et al. 2011. Combined effects of atorvastatin and metformin on glucose-induced variations of inflammatory process in patients with diabetes mellitus. Int J Cardiol, 149 (1), pp. 46-49. | Show Abstract | Read more

BACKGROUND: Statin treatment improves survival in patients with atherosclerosis, but their effect on the glucose-induced variations of inflammatory markers, is unknown. We examined the effect of combined therapy with atorvastatin and metformin on glucose-induced variations of inflammatory molecules in patients with newly diagnosed diabetes mellitus type 2 (DM). METHODS: Thirty five subjects with newly diagnosed DM were randomized to receive metformin 850 mg/d (M, n=17) or metformin 850 mg/d+atorvastatin 10mg (n=18). All subjects underwent glucose loading (75 g oral glucose) at baseline and after 12 weeks of treatment. Blood samples were obtained at baseline and 3h post-loading, while serum tumor necrosis factor alpha (TNF-α) levels were determined at baseline and at 3h. RESULTS: Serum TNF-α remained unchanged in metformin at baseline (1.36±0.18 to 1.47±0.21 pg/ml p=NS) and after treatment (1.44±0.71 to 1.31±0.17 pg/ml, p=NS), while it was reduced in metformin+atorvastatin (2.3±0.3 to 2.0±0.4 pg/ml, p=NS at baseline and 1.80±0.2 to 1.65±0.2 pg/ml, p=0.03 after treatment). CONCLUSIONS: Interestingly, the combination of metformin and atorvastatin partly prevents the glucose-loading induced elevation of glucose levels (at 1 h), suggesting a better response to glucose intake than monotherapy with metformin. In addition, combined treatment with atorvastatin and metformin reduces the post-glucose loading levels of TNF-α compared to metformin monotherapy.

Antonopoulos AS, Lee R, Margaritis M, Antoniades C. 2011. Adiponectin as a regulator of vascular redox state: therapeutic implications. Recent Pat Cardiovasc Drug Discov, 6 (2), pp. 78-88. | Show Abstract | Read more

Recently, adipose tissue has been implicated in the regulation of vascular function in humans. This regulatory function is mediated via the release of vasoactive cytokines called adipokines. Adiponectin is an adipokine with powerful anti-inflammatory and antioxidant properties being dysregulated in obesity and in insulin resistance states. In both in vitro and in vivo models adiponectin has been shown to increase nitric oxide bioavailability, improve endothelial function, and exert beneficial effects on vascular smooth muscle cell function. Strategies to upregulate adiponectin expression or to potentiate adiponectin signalling may favourably modulate vascular redox state and therefore reduce cardiovascular risk. Various drug classes such as glitazones, newer sulfonylureas, angiotensin receptor blockers, ACE inhibitors and nicotinic acid exert beneficial effects on insulin resistance partly by increasing plasma adiponectin levels. Others such as tetrahydrobiopterin or certain antioxidants are also promising in normalizing plasma adiponectin levels. Given the central role of adiponectin in vascular disease states and obesity-related metabolic disorders, improving adiponectin vascular or systemic bioavailability via existing drugs or novel therapeutic strategies may be valuable in the prevention of cardiovascular disease in humans. The discussion of recent patents for the adiponectin as a regulator of vascular redox state also included in this review article.

Koumallos N, Paschalis A, Dimarakis I, Antoniades C. 2011. Bypass surgery in a patient with single coronary artery. Eur J Cardiothorac Surg, 39 (5), pp. e144. | Read more

Michaelides AP, Soulis D, Antoniades C, Antonopoulos AS, Miliou A, Ioakeimidis N, Chatzistamatiou E, Bakogiannis C, Marinou K, Liakos C, Stefanadis C. 2011. Exercise duration as a determinant of vascular function and antioxidant balance in patients with coronary artery disease. Heart, 97 (10), pp. 832-837. | Show Abstract | Read more

BACKGROUND: Exercise improves the clinical outcome of patients with coronary artery disease (CAD); however, the ideal exercise duration for each patient remains unclear. OBJECTIVE: To investigate the effects of exercise duration on arterial elastic properties and antioxidant/pro-oxidant mechanisms in patients with CAD. DESIGN, SETTING, PATIENTS, INTERVENTIONS: Sixty male patients with CAD were randomised into two groups, and underwent exercise for 30 min or 60 min in a crossover design with 2 weeks' wash-out period. In all participants aortic and radial blood pressures (BP) and arterial elastic properties (augmentation index (AIx)/pulse wave velocity (PWV)) were determined at baseline and 24 h after exercise. Plasma malonyldialdehyde (MDA) and superoxide dismutase (SOD)1 and SOD2 levels were also measured. RESULTS: Exercise had no effect on aortic and radial BP (p=NS for all). Walking for 30 min improved AIx (from 33.79 ± 0.91% to 31.73 ± 0.86%, p<0.001) and PWV (from 9.26 ± 0.95 m/s to 9.06 ± 0.21 m/s, p<0.001), while exercise for 60 min had adverse effects on vascular stiffness (for AIx: from 33.37 ± 0.93% to 33.73 ± 1.05%, p=NS and for PWV: from 9.25 ± 0.19 m/s to 9.37 ± 0.21 m/s, p < 0.05 mainly in older patients). Exercise for 60 min was associated with a significant 20% increase in MDA levels (p<0.05). Exercise had no effects on SOD1 levels, however it significantly increased SOD2 levels after 30 min (from 2.26 ± 0.22 ng/mL to 2.36 ± 0.18 ng/mL, p < 0.05) but not after 60 min (p=NS). Conclusion Shorter exercise duration was associated with favourable antioxidant and vascular effects, while longer exercise blunted these beneficial effects and was accompanied by adverse effects on vascular function, mainly in older coronary patients. Further studies are required to explore the hypothesis that a more individualised approach to the selection of the appropriate exercise programme should be considered for patients with CAD.

Michaelides AP, Massias S, Antoniades C, Tsiachris D, Dilaveris P, Aggelis A, Liakos C, Marinou K, Raftopoulos L, Soulis D, Stefanadis C. 2011. Novel methodology for the detection of exercise-induced myocardial wall motion abnormalities by surface electrocardiogram during exercise test. J Electrocardiol, 44 (3), pp. 377-382. | Show Abstract | Read more

BACKGROUND: We investigated whether ischemia-induced wall motion abnormalities during exercise test modify electrical vector variation. METHODS: We performed treadmill exercise test and thallium 201 scintigraphy in 150 normotensives. Beat-to-beat change of direction of S wave in V(1) (reference lead) was compared with that of R wave in V(5) and aVF, representative of anterior and inferior walls, respectively. The percentage of neighboring QRS couples where S wave in V(1) and R wave in V(5) or aVF change toward the same direction (increase or decrease) constitutes V1-V5 and V1-aVF indexes. RESULTS: V1-V5 and V1-aVF indexes were significantly decreased in subjects with reversible anterior or inferior ischemia, respectively. A decrease in V1-V5 index ≥0.14 defines those with anterior wall ischemia (sensitivity, 100%; specificity, 75.5%), whereas a decrease in V1-aVF index ≥0.05 defines those with inferior wall ischemia (sensitivity, 92.3%; specificity, 61.5%). CONCLUSIONS: These novel electrocardiographic exercise test indexes improved significantly their sensitivities.

Antoniades C. 2011. Oxidative stress in the vascular wall: a useful physiological process or a therapeutic target in vascular disease? Recent Pat Cardiovasc Drug Discov, 6 (2), pp. 74-77. | Read more

Tousoulis D, Antoniades C, Marinou K, Stefanadi E, Latsios G, Stefanadis C. 2011. Novel therapies targeting vascular endothelium pp. 215-242. | Show Abstract

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature, may improve the long-term outcome in healthy individuals, high-risk subjects or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of NO in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, novel antioxidant compounds or combinations of classic antioxidant agents as well as substances which target endothelial nitric oxide synthase 'coupling'. In the future genetic profile may help to identify potential responders to treatments targeting specific intracellular pathways in vascular endothelium. ©2011 Nova Science Publishers, Inc. All rights reserved.

Briasoulis A, Tousoulis D, Antoniades C, Stefanadis C. 2011. Progenitor cells and vascular endothelium pp. 191-213. | Show Abstract

Endothelial progenitor cells (EPCs) are under investigation due to their association with vascular injury. In response to chemotactic stimuli they are mobilized from bone-marrow and non-bone marrow sites, they migrate, adhere and home to the injured vessel. Numerous molecular and cellular pathways participate and converge to the EPCs mediated vascular repair. However, the exact phenotypic properties, modes of functions and effects in vascular diseases and particularly in atherosclerosis are under investigation. Endothelial progenitor cells represent a heterogeneous group of cells in different stages of differentiation, from hematopoietic bone marrow progenitors to mature endothelial cells which participate in adult vascular repair under ischemic or apoptotic stimuli. This review aims to provide an integrative view of EPC-mediated vascular repair. ©2011 Nova Science Publishers, Inc. All rights reserved.

Antoniades C, Antonopoulos AS, Tousoulis D, Shirodaria C, Bakogiannis C, Stefanadis C. 2011. Evaluation of endothelial function pp. 47-68. | Show Abstract

Endothelium is a multifunctional signal-transducing surface that regulates vascular homeostasis through the release of a variety of autocrine and paracrine substances, that can lead to the development of atherosclerotic plaques. Therefore, the invasive and non-invasive assessment of endothelial function is widely used as an experimental tool in clinical research, while strong evidence suggests that it could also be used in clinical practice in the near future. Several invasive and non-invasive techniques have been developed during the last two decades to evaluate and quantify endothelial dysfunction. Invasive techniques which involve intracoronary or intrabrachial infusions of vasoacting agents are still considered to be the gold standard for the early detection of endothelial dysfunction. Non-invasive techniques include flow-mediated dilatation (FMD) of peripheral arteries using an ultrasound probe, gauge-strain plethysmography that uses the changes in impedance to evaluate the changes in forearm blood flow during reactive hyperemia and magnetic resonance imaging (MRI) which bears great potential in evaluating vascular anatomy and function due to its high temporal and spatial resolution compared to ultrasound-based techniques. All of these techniques contribute the identification of endothelial dysfunction that mandates more aggressive treatment and better control of cardiovascular risk factors in order to improve patients' prognosis. © 2011 Nova Science Publishers, Inc. All rights reserved.

Papageorgiou N, Tousoulis D, Psaltopoulou T, Giolis A, Antoniades C, Tsiamis E, Miliou A, Toutouzas K, Siasos G, Stefanadis C. 2011. Divergent anti-inflammatory effects of different oil acute consumption on healthy individuals. Eur J Clin Nutr, 65 (4), pp. 514-519. | Show Abstract | Read more

BACKGROUND/OBJECTIVES: Inter-cellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1) and tumor necrosis factor-α (TNF-α), are implicated in atherogenesis. In addition, several types of oil as part of different types of diet are associated with the initiation of atherosclerosis and consequently with the risk of cardiovascular disease. However, the exact role of oil consumption on vascular inflammation remains unknown. In this parallel study, we assessed the acute effects of extra virgin olive oil, soy oil, corn oil and cod liver oil on circulating soluble(s) forms of adhesion molecules and TNF-α. SUBJECTS/METHODS: In all, 67 healthy volunteers were randomized to receive 50 ml of oil. Soluble forms of VCAM-1, ICAM-1 and TNF-α were measured by enzyme-linked immunosorbent assay at baseline and at 3 h post oil consumption. RESULTS: All types of oil had no significant effect on soluble VCAM-1 levels (P=nonsignificant (NS) for all). On the contrary, all oil types decreased ICAM-1 levels (P<0.01). Olive oil (P<0.05), soy oil and cod liver oil (P<0.01 for both) reduced TNF-α levels significantly, in contrast to corn oil, which induced a nonsignificant decrease (P=NS). Moreover, there was a significant correlation between the absolute change in ICAM-1 and TNF-α levels (ρ=0.379, P<0.05), but not between the absolute changes in VCAM-1 and TNF-α levels (ρ=0.019, P=NS). CONCLUSIONS: Acute consumption of all types of oil decreased significantly ICAM-1 levels. In addition, olive oil, soy oil and cod liver oil decreased significantly TNF-α levels. Moreover, the absolute change in TNF-α levels was correlated with the absolute change in ICAM-1 levels. These findings indicate that acute consumption of specific types of oil is associated with specific significant anti-inflammatory effects.

Lim CC, van Gaal WJ, Testa L, Cuculi F, Arnold JR, Karamitsos T, Francis JM, Petersen SE, Digby JE, Westaby S et al. 2011. With the "universal definition," measurement of creatine kinase-myocardial band rather than troponin allows more accurate diagnosis of periprocedural necrosis and infarction after coronary intervention. J Am Coll Cardiol, 57 (6), pp. 653-661. | Show Abstract | Read more

OBJECTIVES: We aimed to assess the differential implications of creatine kinase-myocardial band (CK-MB) and troponin measurement with the universal definition of periprocedural injury after percutaneous coronary intervention. BACKGROUND: Differentiation between definitions of periprocedural necrosis and periprocedural infarction has practical, sociological, and research implications. Troponin is the recommended biomarker, but there has been debate about the recommended diagnostic thresholds. METHODS: Thirty-two patients undergoing multivessel percutaneous coronary intervention and late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging in a prospective study had cardiac troponin I, CK-MB, and inflammatory markers (C-reactive protein, serum amyloid A, myeloperoxidase, tumor necrosis factor alpha) measured at baseline, 1 h, 6 h, 12 h, and 24 h after the procedure. Three "periprocedural injury" groups were defined with the universal definition: G1: no injury (biomarker <99th percentile); G2: periprocedural necrosis (1 to 3 × 99th percentile); G3: myocardial infarction (MI) type 4a (>3 × 99th percentile). Differences in inflammatory profiles were analyzed. RESULTS: With CK-MB there were 17, 10, and 5 patients in groups 1, 2, and 3, respectively. Patients with CK-MB-defined MI type 4a closely approximated patients with new CMR-LGE injury. Groups defined with CK-MB showed progressively increasing percentage change in C-reactive protein and serum amyloid A, reflecting increasing inflammatory response (p < 0.05). Using cardiac troponin I resulted in 26 patients defined as MI type 4a, but only a small minority had evidence of abnormality on CMR-LGE, and only 3 patients were defined as necrosis. No differences in inflammatory response were evident when groups were defined with troponin. CONCLUSIONS: Measuring CK-MB is more clinically relevant for diagnosing MI type 4a, when applying the universal definition. Current troponin thresholds are oversensitive with the arbitrary limit of 3 × 99th percentile failing to discriminate between periprocedural necrosis and MI type 4a. (Myocardial Injury following Coronary Artery bypass Surgery versus Angioplasty: a randomised controlled trial using biochemical markers and cardiovascular magnetic resonance imaging; ISRCTN25699844).

Michaelides A, Tousoulis D, Liakos C, Aggeli K, Antoniades C, Vyssoulis G, Raftopoulos L, Soulis D, Toutouzas K, Stefanadis C. 2011. The significance of right-sided chest leads in exercise testing for the detection of right ventricular dysfunction post myocardial infarction of the inferior wall. Int J Cardiol, 146 (3), pp. 330-333. | Show Abstract | Read more

BACKGROUND: The incorporation of right-sided chest leads (V(3)R-V(5)R) into the standard exercise testing has been reported to improve its diagnostic accuracy. The purpose of this study was to evaluate the ability of exercise testing in detecting right ventricular (RV) dysfunction post myocardial infarction (MI) of the inferior wall, using additional V(3)R-V(5)R leads. METHODS: We studied 133 patients (59 ± 5 years, 81 males) with a history of inferior MI due to right coronary artery obstruction (affirmed with coronary angiography). All patients underwent an echocardiographic assessment of RV function 4 weeks after discharge and an exercise treadmill test in order to detect possible RV dysfunction. Recordings during exercise were obtained with the standard 12 leads plus V(3)R-V(5)R. RESULTS: From 133 patients, 97 (group A) presented with normal right ventricle according to the echocardiographic study while the rest 36 patients (group B) presented with RV dysfunction. Maximal exercise-induced ST-segment deviation (in mm) was similar in the standard 12 leads for the 2 groups (2.1 ± 0.4 vs 1.8 ± 0.3, p = NS) while in V(3)R-V(5)R it was greater in group B (0.7 ± 0.3 vs 1.4 ± 0.4, p<0.05). Sensitivity, positive prognostic value, negative prognostic value and accuracy of exercise testing in detecting RV dysfunction were all improved using V(3)R-V(5)R (78 vs 47%, 39 vs 29%, 87 vs 75%, 62 vs 55% respectively, p<0.05 for all) while specificity was not deteriorated (56 vs 58%, p = NS). CONCLUSIONS: The addition of right-sided chest leads (V(3)R-V(5)R) improves the diagnostic ability of standard exercise testing in detecting and especially in excluding RV dysfunction post inferior MI.

Koumallos N, Tousoulis D, Antoniades C, Antonopoulos AS, Stefanadis C. 2011. Genetic polymorphism A1675G of the angiotensin type 2 receptor and its role in hypertension Archives of Hellenic Medicine, 28 (2), pp. 219-223. | Show Abstract

The angiotensin type 2 receptor (AT2R) plays a crucial role in the regulation of blood pressure and atherogenesis. The AT2R gene is located on chromosome X and the biological effect of polymorphism A1675G in this gene still needs to be further specified. This is a review of all the studies examining the role of A1675G in arterial hypertension and cardiac disease. © Athens Medical Society.

Tousoulis D, Papageorgiou N, Latsios G, Siasos G, Antoniades C, Stefanadis C. 2011. C-reactive protein and endothelial dysfunction: Gazing at the coronaries International Journal of Cardiology,

Kardara D, Tousoulis D, Antoniades C, Koumallos N, Xaplanteris P, Kyvelou S-M, Papageorgiou N, Vasiliadou C, Vlachopoulos C, Stefanadis C. 2011. Effects of the Ala379Val polymorphism of lipoprotein-associated phospholipase A2 on thrombosis and inflammation in hypertensive patients International Journal of Cardiology,

Demosthenous M, Antoniades C, Tousoulis D, Margaritis M, Marinou K, Stefanadis C. 2011. Endothelial nitric oxide synthase in the vascular wall: Mechanisms regulating its expression and enzymatic function Artery Research, 5 (2), pp. 37-49. | Show Abstract | Read more

Endothelial nitric oxide synthase (eNOS) is the main source of nitric oxide (NO) in the vascular wall, a molecule with anti-inflammatory, antithrombotic, vasorelaxant, antioxidant and finally antiatherogenic properties. eNOS is expressed in vascular endothelium, and it uses l-arginine as a substrate, while it also requires the presence of multiple co-factors such as tetrahydrobiopterin (BH4), nicotinamide adenine dinucleotide phosphate-oxidase (NADPH) and others. In the presence of BH4 deficiency, this enzyme becomes uncoupled, and it is turned into a source of superoxide radicals instead of NO. Therefore, under these conditions which are present in patients with advanced atherosclerosis, eNOS in human vascular endothelium is largely a source of reactive oxygen species, inducing in this way atherogenesis. Therefore, the aim of future therapeutic strategies targeting atherosclerosis through regulation of eNOS physiology, should take into account that up-regulation of this enzyme in the vascular wall may not lead to a respective increase of NO bioavailability and improvement of vascular homeostasis, but it may actually induce intravascular oxidative stress, if intracellular bioavailability of eNOS co-factors is not simultaneously elevated. In conclusion, eNOS plays a critical role in the regulation of vascular homeostasis, and it is a therapeutic target against atherogenesis. © 2011 Association for Research into Arterial Structure and Physiology.

Demosthenous M, Antoniades C, Tousoulis D, Margaritis M, Marinou K, Stefanadis C. 2011. Endothelial nitric oxide synthase in the vascular wall: Mechanisms regulating its expression and enzymatic function Artery Research,

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Antoniades C, Cunnington C, Antonopoulos A, Neville M, Margaritis M, Demosthenous M, Bendall J, Hale A, Cerrato R, Tousoulis D et al. 2011. Induction of vascular GTP-cyclohydrolase i and endogenous tetrahydrobiopterin synthesis protect against inflammation-induced endothelial dysfunction in human atherosclerosis Circulation, 124 (17), pp. 1860-1870. | Show Abstract | Read more

BACKGROUND-: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) is essential for maintenance of enzymatic function. We hypothesized that induction of BH4 synthesis might be an endothelial defense mechanism against inflammation in vascular disease states. METHODS AND RESULTS-: In Study 1, 20 healthy individuals were randomized to receive Salmonella typhi vaccine (a model of acute inflammation) or placebo in a double-blind study. Vaccination increased circulating BH4 and interleukin 6 and induced endothelial dysfunction (as evaluated by brachial artery flow-mediated dilation) after 8 hours. In Study 2, a functional haplotype (X haplotype) in the GCH1 gene, encoding GTP-cyclohydrolase I, the rate-limiting enzyme in biopterin biosynthesis, was associated with endothelial dysfunction in the presence of high-sensitivity C-reactive protein in 440 coronary artery disease patients. In Study 3, 10 patients with coronary artery disease homozygotes for the GCH1 X haplotype (XX) and 40 without the haplotype (OO) underwent S Typhi vaccination. XX patients were unable to increase plasma BH4 and had a greater reduction of flow-mediated dilation than OO patients. In Study 4, vessel segments from 19 patients undergoing coronary bypass surgery were incubated with or without cytokines (interleukin-6/tumor necrosis factor-α/lipopolysaccharide) for 24 hours. Cytokine stimulation upregulated GCH1 expression, increased vascular BH4, and improved vasorelaxation in response to acetylcholine, which was inhibited by the GTP-cyclohydrolase inhibitor 2,4-diamino-6-hydroxypyrimidine. CONCLUSIONS-: The ability to increase vascular GCH1 expression and BH4 synthesis in response to inflammation preserves endothelial function in inflammatory states. These novel findings identify BH4 as a vascular defense mechanism against inflammation-induced endothelial dysfunction. © 2011 American Heart Association, Inc.

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Antoniades C, Bakogiannis C, Leeson P, Guzik TJ, Zhang MH, Tousoulis D, Antonopoulos AS, Demosthenous M, Marinou K, Hale A et al. 2011. Rapid, direct effects of statin treatment on arterial redox state and nitric oxide bioavailability in human atherosclerosis via tetrahydrobiopterin- mediated endothelial nitric oxide synthase coupling Circulation, 124 (3), pp. 335-345. | Show Abstract | Read more

Background-: Treatment with statins improves clinical outcome, but the exact mechanisms of pleiotropic statin effects on vascular function in human atherosclerosis remain unclear. We examined the direct effects of atorvastatin on tetrahydrobiopterin-mediated endothelial nitric oxide (NO) synthase coupling in patients with coronary artery disease. Methods and Results-: We first examined the association of statin treatment with vascular NO bioavailability and arterial superoxide (O 2 .- ) in 492 patients undergoing coronary artery bypass graft surgery. Then, 42 statin-naïve patients undergoing elective coronary artery bypass graft surgery were randomized to atorvastatin 40 mg/d or placebo for 3 days before surgery to examine the impact of atorvastatin on endothelial function and O 2 .- generation in internal mammary arteries. Finally, segments of internal mammary arteries from 26 patients were used in ex vivo experiments to evaluate the statin-dependent mechanisms regulating the vascular redox state. Statin treatment was associated with improved vascular NO bioavailability and reduced O 2 .- generation in internal mammary arteries. Oral atorvastatin increased vascular tetrahydrobiopterin bioavailability and reduced basal and N-nitro-L-arginine methyl ester-inhibitable O 2 .- in internal mammary arteries independently of low-density lipoprotein lowering. In ex vivo experiments, atorvastatin rapidly improved vascular tetrahydrobiopterin bioavailability by upregulating GTP-cyclohydrolase I gene expression and activity, resulting in improved endothelial NO synthase coupling and reduced vascular O 2 .- . These effects were reversed by mevalonate, indicating a direct effect of vascular hydroxymethylglutaryl- coenzyme A reductase inhibition. Conclusions-: This study demonstrates for the first time in humans the direct effects of statin treatment on the vascular wall, supporting the notion that this effect is independent of low-density lipoprotein lowering. Atorvastatin directly improves vascular NO bioavailability and reduces vascular O 2 .- through tetrahydrobiopterin- mediated endothelial NO synthase coupling. These findings provide new insights into the mechanisms mediating the beneficial vascular effects of statins in humans. Clinical Trial Registration-: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01013103. © 2011 American Heart Association, Inc.

Antoniades C, Tousoulis D, Koutsilieris M, Stefanadis C. 2011. Response to Asymmetrical Dimethylarginine, Oxidative Stress, and Atherosclerosis HYPERTENSION, 58 (5), pp. E186-E186. | Read more

Briasoulis A, Tousoulis D, Antoniades C, Papageorgiou N, Stefanadis C. 2011. The role of endothelial progenitor cells in vascular repair after arterial injury and atherosclerotic plaque development. Cardiovasc Ther, 29 (2), pp. 125-139. | Show Abstract | Read more

Endothelial progenitor cells (EPCs) are under investigation due to their association with vascular injury. In response to chemotactic stimuli they are mobilized from bone-marrow and nonbone marrow sites, they migrate, adhere and home to the injured vessel. Numerous molecular and cellular pathways participate and converge to the EPCs mediated vascular repair. However, the exact phenotypic properties, modes of functions and effects in vascular diseases and particularly in atherosclerosis are under investigation. EPCs represent a heterogeneous group of cells in different stages of differentiation, from hematopoietic bone marrow progenitors to mature endothelial cells that participate in adult vascular repair under ischemic or apoptotic stimuli. This review aims to provide an integrative view of EPC-mediated vascular repair.

Lee R, Antoniades C, Adlam D, Channon KM. 2012. Treatment of recurrent vein graft "stent-in-stent" re-stenosis guided by optical coherence tomography. Int J Cardiol, 156 (1), pp. e20-e21. | Read more

Tousoulis D, Andreou I, Tentolouris C, Antoniades C, Papageorgiou N, Gounari P, Kotrogiannis I, Miliou A, Charakida M, Trikas A, Stefanadis C. 2010. Comparative effects of rosuvastatin and allopurinol on circulating levels of matrix metalloproteinases and tissue inhibitors of metalloproteinases in patients with chronic heart failure. Int J Cardiol, 145 (3), pp. 438-443. | Show Abstract | Read more

BACKGROUND: Patients with chronic heart failure (HF) are characterized by alterations in matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) levels. However, the impact of hypolipidemic and antioxidant treatment in MMPs and TIMPs is unknown. In the present study, we sought to compare the effects of statins and xanthine oxidase inhibitors on circulating levels of MMPs and TIMPs in patients with chronic HF. METHODS: Forty-two clinically stable patients with mild to moderate HF were randomized to receive rosuvastatin 10 mg or allopurinol 300 mg daily and followed up for 1 month. Serum levels of MMP-2, -9, TIMP-1, and -2 were measured before and after treatment. RESULTS: Levels of MMP-2 and -9 were significantly decreased in the rosuvastatin group (from 251±52 ng/ml and 400±206 ng/ml to 215±47 ng/ml and 309±166 ng/ml, p<0.001 and p<0.05 respectively), but not in the allopurinol group. In the rosuvastatin group, TIMP-2 levels were significantly increased (from 85±17 ng/ml to 93±16 ng/ml, p<0.05), while TIMP-1 remained unchanged. In the allopurinol group, no significant changes were observed regarding the levels of TIMPs. CONCLUSIONS: Short-term rosuvastatin but not allopurinol administration decreases MMP-2 and -9 and increases TIMP-2 levels.

Antoniades C, Bakogiannis C, Tousoulis D, Demosthenous M, Marinou K, Stefanadis C. 2010. Platelet activation in atherogenesis associated with low-grade inflammation. Inflamm Allergy Drug Targets, 9 (5), pp. 334-345. | Show Abstract | Read more

Further to the established role of platelets in thrombosis and hemostasis, increasing evidence suggests that they also play a crucial role in atherogenesis. Platelets produce a number of agents contributing to the systemic low-grade inflammation implicated in atherogenesis. Platelet activation following inflammatory stimulus leads to the expression of surface receptors such as GPIb/IX/V, P-selectin, CD40, and to the release of several pro-inflammatory agents. Platelet receptors and released molecules play a critical role during the initiation and the progression of atherosclerosis by mediating leukocytes recruitment and adhesion to the vascular wall. Endothelial dysfunction, an early feature in atherosclerosis, is associated with low-grade inflammation within the vascular wall, and it leads to the reduced bioavailability of nitric oxide. Dysfunctional endothelium itself releases inflammatory molecules leading toward platelets activation and adhesion to the vascular wall. Platelets are no longer considered simply as cells participating in thrombosis. They are regulators of multiple processes in the human body, including inflammation, regulation of endothelial physiology and atherogenesis. The design of new therapeutic strategies targeting platelets and their impact in atherosclerosis-related low-grade inflammation are in the center of current cardiovascular research.

Antoniades C, Channon KM, Stefanadis C. 2010. Letter by Antoniades et al regarding article, "Uncoupled cardiac nitric oxide synthase mediates diastolic dysfunction". Circulation, 122 (21), pp. e558. | Read more

Tousoulis D, Antoniades C, Tsiamis E, Charakida M, Siasos G, Tsioufis C, Stefanadis C. 2010. Gene therapy for dysfunctional endothelium: is dimethylarginine dimethylaminohydrolase-2 a therapeutic target? Int J Cardiol, 144 (2), pp. 173-174. | Read more

Antoniades C, Psarros C, Tousoulis D, Bakogiannis C, Shirodaria C, Stefanadis C. 2010. Nanoparticles: a promising therapeutic approach in atherosclerosis. Curr Drug Deliv, 7 (4), pp. 303-311. | Show Abstract | Read more

Coronary atherosclerosis is the largest cause of mortality and morbidity in industrialised countries. Despite recent advances in medical therapies, the prevention and treatment of atherosclerosis remain suboptimal. Atherosclerosis is considered to be a chronic inflammatory disease of the arterial wall, involving the accumulation of macrophages and excess low density lipoproteins (LDL), the formation of foam cells which create the atheromatous plaque, resulting in stenosis, aneurysm and plaque rupture leading to acute coronary events. Every step in the atherogenesis process is a potential therapeutic target for both the prevention and regression of atherosclerosis. A novel approach is the use of nanoparticles containing drugs, providing new perspectives in targeted modification of these pathways. Nanoparticles are ultrafine particles sized between 1-100 nm. By using specific methods, nanoparticles can be filled with drugs and achieve targeted drug delivery near the diseased area. In this review article we describe the basic actions of nanoparticles, and we discuss their potential applications in atherosclerosis. We also discuss their advantages and we expose the existing toxicity issues, making it clear however, that the use of nanoparticles is one of the most promising therapeutic strategies against atherosclerosis.

Antoniades C, Bakogiannis C, Tousoulis D, Reilly S, Zhang MH, Paschalis A, Antonopoulos AS, Demosthenous M, Miliou A, Psarros C et al. 2010. Preoperative atorvastatin treatment in CABG patients rapidly improves vein graft redox state by inhibition of Rac1 and NADPH-oxidase activity. Circulation, 122 (11 Suppl), pp. S66-S73. | Show Abstract | Read more

BACKGROUND: Statins improve clinical outcome of patients with atherosclerosis, but their perioperative role in patients undergoing coronary artery bypass grafting (CABG) is unclear. We hypothesized that short-term treatment with atorvastatin before CABG would improve the redox state in saphenous vein grafts (SVGs), independently of low-density lipoprotein cholesterol (LDL)-lowering. METHODS AND RESULTS: In a randomized, double-blind controlled trial, 42 statin-naïve patients undergoing elective CABG received atorvastatin 40 mg/d or placebo for 3 days before surgery. Circulating inflammatory markers and malondialdehyde (MDA) were measured before and after treatment. SVG segments were used to determine vascular superoxide (O(2)(*-)) and Rac1 activation. For ex vivo studies, SVG segments from 24 patients were incubated for 6 hours with atorvastatin 0, 5, or 50 μmol/L. Oral atorvastatin reduced vascular basal and NADPH-stimulated O(2)(*-) in SVGs (P<0.05 for all versus placebo) and reduced plasma MDA (P<0.05), independently of LDL-lowering and of changes in inflammatory markers. In SVGs exposed to atorvastatin ex vivo, without exposure to LDL, basal and NADPH-stimulated O(2)(·-) were significantly reduced (P<0.01 for both concentrations versus 0 μmol/L) in association with a striking reduction in Rac1 activation and 1 membrane-bound Rac1 and p67(phox) subunit. The antioxidant effects of atorvastatin were reversed by mevalonate, implying a dependence on vascular HMG-CoA reductase inhibition. CONCLUSIONS: Short-term treatment with atorvastatin 40 mg/d before CABG improves redox state in SVGs, by inhibiting vascular Rac1-mediated activation of NADPH-oxidase. These novel findings suggest that statin therapy should be maintained or initiated in patients undergoing CABG, independently of LDL levels. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01013103.

Katsi V, Tousoulis D, Chatzistamatiou E, Androulakis E, Moustakas G, Skiadas I, Tsioufis C, Antoniades C, Stefanadis CI, Kallikazaros IE. 2010. A 31 year old woman with essential hypertension grade III and branch retinal vein occlusion with homozygous C677T MTHFR hyperhomocysteinemia and high Lp(a) levels. Int J Cardiol, 143 (3), pp. e42-e44. | Show Abstract | Read more

We report a 31-year old woman with essential hypertension grade III and history of branch retinal vein occlusion in the setting of hyperhomocysteinemia due to homozygous MTHFR gene mutation and elevated Lp(a). The patient was treated successfully with antihypertensive treatment, acetylsalicylic acid and multivitamin complex supplementation.

Tousoulis D, Koniari K, Antoniades C, Miliou A, Noutsou M, Nikolopoulou A, Papageorgiou N, Marinou K, Stefanadi E, Stefanadis C. 2010. Impact of 6 weeks of treatment with low-dose metformin and atorvastatin on glucose-induced changes of endothelial function in adults with newly diagnosed type 2 diabetes mellitus: A single-blind study. Clin Ther, 32 (10), pp. 1720-1728. | Show Abstract | Read more

BACKGROUND: Statin treatment has been reported to improve survival in patients with atherosclerosis, partly by improving vascular endothelial function. Elevation of blood glucose concentrations impairs endothelial function and promotes atherogenesis, but the effect of statins on glucose-induced endothelial dysfunction is unknown. Endothelium-dependent dilation (EDD) measured by gauge-strain plethysmography in the forearm is considered to be a reliable marker of endothelial function in forearm resistance vessels. OBJECTIVE: This study examined the combined effects of metformin and atorvastatin treatment on glucose-induced endothelial dysfunction (as EDD) in patients with newly diagnosed type 2 diabetes mellitus (DM). METHODS: Patients with newly diagnosed DM were recruited and were randomly assigned to receive metformin 850 mg/d or metformin 850 mg/d + atorvastatin 10 mg/d for 6 weeks in a single-blind study. All patients underwent glucose loading (75 g oral glucose after 12 hours of fasting) at baseline and at the end of the treatment period. Blood samples were obtained at baseline before glucose loading and 3 hours after loading to determine serum concentrations of cholesterol, lipoproteins, triglycerides, glucose, and glycosylated hemoglobin. EDD was evaluated at baseline and at 1, 2, and 3 hours after loading. The investigators were blinded to the treatment group assignments, and all analyses were performed in a blinded manner. Adverse events (eg, gastrointestinal disorders, myopathy, liver disorders) were monitored based on reported symptoms or signs (eg, myalgias, muscle cramps), clinical examination, and laboratory parameters (eg, increased liver and muscle enzymes). RESULTS: Thirty-two white patients with newly diagnosed type 2 DM were randomly assigned to receive metformin 850 mg/d (n = 17 [12 men]; mean [SD] age, 53.88 [45] years; body mass index [BMI], 28.7 [4.5] kg/m²) or metformin 850 mg/d + atorvastatin 10 mg/d (n = 15 [6 men]; mean age, 52.53 [37] years; BMI, 28.5 [2.1] kg/m²). At baseline, EDD was reduced 1 and 2 hours after glucose loading in both study groups (P < 0.01). Glucose loading was associated with an elevation of blood glucose concentrations at 1 and 2 hours (P < 0.01 vs resting levels before loading), and concentrations returned to resting levels at 3 hours, in both groups at baseline and after treatment. Metformin alone or in combination with atorvastatin was associated with a significant reduction in resting glucose concentrations after 6 weeks (both, P < 0.05 vs baseline), but only the combination of metformin + atorvastatin partly prevented the glucose-induced elevation of serum glucose at 1 hour after loading and the glucose-induced decrease in EDD (both, P < 0.01 vs baseline). CONCLUSIONS: Glucose loading blunted endothelial function, with a deterioration in EDD, in these patients with newly diagnosed type 2 DM. However, combined treatment with metformin and atorvastatin for 6 weeks partly prevented the glucose-induced impairment of EDD in these patients, with a significant difference compared with monotherapy with metformin.

Michaelides AP, Tousoulis D, Raftopoulos LG, Antoniades C, Tsiachris D, Stefanadis CI. 2010. The impact of novel exercise criteria and indices for the diagnostic and prognostic ability of exercise testing. Int J Cardiol, 143 (2), pp. 119-123. | Show Abstract | Read more

Exercise testing (ET) stands as one of the most easy, affordable, cost effective, non invasive methods for diagnosing coronary heart disease. Its sensitivity, specificity and prognostic value, especially in the prime era of its implementation in the cardiac diagnostic procedure, is relatively limited. Novel exercise criteria and indices based either on ST segment changes or ST segment independent parameters, such as "Athens QRS score", have greatly improved the diagnostic ability and accuracy of ET. Complex ECG-derived indices linked to ST changes along with the use of right-sided precordial leads have also enhanced the diagnostic accuracy of ET with respect to the extent of ischemic heart disease and the detection of specific culprit vessels. ET contains also a prognostic value, since several ET-derived parameters have been associated with adverse outcome, including ST changes, blood pressure and heart rate response to exercise and duration of exercise.

Tousoulis D, Koutsogiannis M, Papageorgiou N, Siasos G, Antoniades C, Tsiamis E, Stefanadis C. 2010. Endothelial dysfunction: potential clinical implications. Minerva Med, 101 (4), pp. 271-284. | Show Abstract

Vascular endothelium is responsible for the secretion of several substances exerting anti-atherogenic effects. Endothelial damage is also crucial for the progress of atherosclerosis and risk factors for atherosclerosis represent crucial factors associated with endothelial dysfunction. Studies have shown that patients with cardiovascular disease are characterized by impaired endothelial function (EF). Therefore, several agents have been proposed as potential modulators of EF. Most of the available approaches include pharmaceutical agents routinely used such as statins, angiotensin converting enzyme inhibitors, antioxidants, L-arginine, insulin sensitizers or others still under investigation such as tetrahydrobiopterin or folic acid (folate). Despite of the fact that there are several strategies aiming to improve endothelial dysfunction by enhancing nitric oxide bioavailability, it is still unclear whether they could be beneficial at a clinical level.

Tousoulis D, Androulakis E, Papageorgiou N, Briasoulis A, Siasos G, Antoniades C, Stefanadis C. 2010. From atherosclerosis to acute coronary syndromes: the role of soluble CD40 ligand. Trends Cardiovasc Med, 20 (5), pp. 153-164. | Show Abstract | Read more

The binding of CD40 ligand (CD40L) to CD40 stimulates inflammatory processes including the release of proinflammatory cytokines and the expression of adhesion molecules implying a role in atherosclerosis. Patients exhibiting hypercholesterolemia, unstable angina, or acute myocardial infarction present with increased CD40L levels. Novel data suggest that elevated soluble CD40L levels not only represent a risk factor for cardiovascular disease but also predict future adverse events, especially in patients with acute coronary syndromes (ACS). Examination of the potential role of the genetic variability on CD40/CD40L genes in ACS, as regards the regulation of CD40L, appears to be of great interest. Moreover, several therapeutic approaches such as statins, antihypertensive agents, and antiplatelet agents have been suggested as potential modulators of CD40L levels anticipating a positive impact on the outcomes of patients with ACS. Whether specific agents target the CD40/CD40L system as well as its pathogenic role in ACS remains to be elucidated by large-scale studies in the future.

Gounari P, Tousoulis D, Antoniades C, Kampoli AM, Stougiannos P, Papageorgiou N, Roulia G, Stefanadi E, Siasos G, Tsioufis C, Stefanadis C. 2010. Rosuvastatin but not ezetimibe improves endothelial function in patients with heart failure, by mechanisms independent of lipid lowering. Int J Cardiol, 142 (1), pp. 87-91. | Show Abstract | Read more

INTRODUCTION: Congestive heart failure (HF) is characterised by increased proinflammatory stimulation and impaired endothelial function. Statin treatment exerts a beneficial effect on endothelial function and inflammatory process in patients with atherosclerosis. However, its effect in patients with HF is not well studied. Therefore, in the present study we compared the effect of short-term treatment with rosuvastatin or ezetimibe on endothelial function in patients with HF. METHODS: In this double-blind, placebo controlled, cross-over trial, 22 patients with HF were randomised to receive ezetimibe 20 mg/d or rosuvastatin 10 mg/d for 4 weeks, with 4 weeks wash-out period between the two interventions. Endothelial function was evaluated by flow mediated dilation (FMD) in the brachial artery at the beginning and at the end of each treatment period. RESULTS: There was no change in the baseline brachial diameter after treatment with either ezetimibe (p=NS) or rosuvastatin (p=NS). However, there was a significant improvement of FMD in the rosuvastatin group (p<0.05) but not in the ezetimibe group (p=NS). The changes in lipid levels were similar between groups (p=NS). The change in FMD was not significantly correlated with the decrease of serum LDL in either the ezetimibe or rosuvastatin treated groups. CONCLUSIONS: Rosuvastatin improves endothelial function in patients with congestive heart failure, by mechanisms independent of lipid-lowering. On the contrary, lipid-lowering treatment achieved by ezetimibe is unable to affect endothelial function in these patients. These findings indicate a direct beneficial effect of statins in patients with congestive heart failure, further to lipid-lowering.

Tousoulis D, Bouras G, Antoniades C, Marinou K, Miliou A, Papageorgiou N, Chatzis G, Tentolouris C, Tsioufis C, Stefanadis C. 2010. The activation of endothelin-1 pathway during methionine-induced homocysteinemia mediates endothelial dysfunction in hypertensive individuals. J Hypertens, 28 (5), pp. 925-930. | Show Abstract | Read more

OBJECTIVES: Endothelin-1 (ET-1) is a key regulator of arterial blood pressure in humans, and homocysteinemia is associated with increased oxidative stress. It is still unclear whether homocysteine-induced oxidative stress is implicated in the regulation of ET-1 expression. We examined the impact of acute homocysteinemia on endothelial function in hypertensive patients and healthy individuals, and the potential role of ET-1. METHODS: In this double-blind, placebo-controlled study, 39 hypertensive and 49 healthy individuals were randomized to receive high-dose vitamins (2 g vitamin C and 800IU vitamin E) or placebo followed by methionine loading 100 mg/kg body weight. Endothelium-dependent dilation (EDD) and endothelium-independent dilation (EID) of the brachial artery were evaluated by plethysmography, at baseline and 4 h postloading (4 h PML). ET-1 was measured by ELISA, whereas total lipid hydroperoxides (per-ox) levels were measured by a commercially available photometric technique. RESULTS: Acute, methionine-induced homocysteinemia decreased EDD in all study groups (P < 0.001 for all), whereas vitamins pretreatment failed to prevent this effect, despite the vitamins-induced reduction of peroxidation in the hypertensives group (P < 0.05). On the contrary, methionine loading significantly increased plasma ET-1 levels only in hypertensives (P < 0.05), an effect which was not prevented by antioxidant vitamins (P < 0.05). EID remained unchanged after methionine loading, in all study groups (P = NS for all groups). CONCLUSION: Experimental homocysteinemia rapidly blunts endothelial function in both hypertensive individuals and healthy individuals. The rapid elevation of ET-1 levels observed only in hypertensives, suggests that ET-1 may be the key mediator of homocysteine-induced endothelial dysfunction, independently of oxidative stress.

Papageorgiou N, Tousoulis D, Antoniades C, Giolis A, Briasoulis A, Stefanadis C. 2010. The impact of statin administration in acute coronary syndromes. Hellenic J Cardiol, 51 (3), pp. 250-261.

Michaelides AP, Liakos CI, Antoniades C, Dilaveris PE, Tsiamis EG, Tsioufis KP, Aggeli KD, Toutouzas KP, Raftopoulos LG, Stefanadis CI. 2010. Right-sided chest leads in exercise testing for detection of coronary restenosis. Clin Cardiol, 33 (4), pp. 236-240. | Show Abstract | Read more

BACKGROUND: The incorporation of right-sided chest leads (V(3)R through V(5)R) into standard exercise testing has been reported to improve its diagnostic utility. HYPOTHESIS: The purpose of this study was to evaluate any improvement in the ability of exercise testing in detecting restenosis, using additional V(3)R through V(5)R leads, in asymptomatic patients undergoing percutaneous coronary intervention (PCI) in the right coronary artery (RCA) or/and left circumflex (LCX). METHODS: We studied 172 consecutive patients (54 +/- 7 years old, 106 males) undergoing PCI in RCA or/and LCX. A treadmill test had been performed before PCI. Six months later, all patients underwent a second treadmill test and arteriography in order to detect silent ischemia due to restenosis. Recordings during exercise were obtained with the standard 12-leads plus V(3)R through V(5)R. RESULTS: Out of 172 patients, 106 had stenosis in RCA, 35 in LCX, and 31 in both vessels while 6 months later, restenosis was detected in 8 (for RCA), 3 (for LCX), and 3 (for both vessels) patients respectively. Sensitivity, specificity, positive prognostic value, negative prognostic value, and accuracy of exercise testing performed post PCI were ameliorated using V(3)R through V(5)R (79% vs 57%, 97% vs 80%, 69% vs 21%, 98% vs 95%, and 95% vs 78% respectively, P < .05 for all except negative prognostic value). Maximal exercise-induced ST-segment deviation (in mm) was not changed post PCI in 12 leads (1.4 +/- 0.2 vs 1.5 +/- 0.2, P = NS) while it was decreased in V(3)R through V(5)R (0.2 +/- 0.2 vs 1.2 +/- 0.3, P < .01). CONCLUSIONS: The addition of V(3)R through V(5)R improves the diagnostic ability of standard exercise testing in detecting silent ischemia due to restenosis in patients undergoing PCI in RCA or/and LCX.

Tousoulis D, Antonopoulos AS, Antoniades C, Saldari C, Stefanadi E, Siasos G, Stougianos P, Plastiras A, Korompelis P, Stefanadis C. 2010. Role of depression in heart failure--choosing the right antidepressive treatment. Int J Cardiol, 140 (1), pp. 12-18. | Show Abstract | Read more

Major depression is a common feature of heart failure patients and possibly stems from their common biochemical background. Depression and heart failure co-morbidity has several clinical implications on the prognosis of these patients. Furthermore antidepressive drugs have known cardiovascular side effects, while their safety and efficacy in heart failure has not been fully elucidated yet. The right choice of antidepressive treatment in heart failure constitutes an issue of high importance as it can affect the clinical outcome of these patients. In this article we highlight the role of major depression in heart failure and demonstrate their common biochemical background. Moreover we review the acquired so far knowledge on the use of the various categories of antidepressants in heart failure by reference to the existing clinical studies on antidepressants efficacy and safety in heart failure. Even though certain conclusions cannot be drawn yet, evidence suggests that the use of selective serotonin reuptake inhibitors may have a beneficial effect on clinical outcome of heart failure patients.

Michaelides AP, Raftopoulos LG, Aggeli C, Liakos C, Antoniades C, Fourlas C, Stamatopoulos E, Ioakeimides N, Soulis D, Stefanadis C. 2010. Correlation of ST-segment "hump sign" during exercise testing with impaired diastolic function of the left ventricle. J Electrocardiol, 43 (2), pp. 167-172. | Show Abstract | Read more

BACKGROUND: The appearance of a discrete upward deflection of the ST segment, termed the ST hump sign during exercise testing has been associated with resting hypertension and exaggerated blood pressure response to exercise. OBJECTIVE: We investigated the correlation between the presence of hump sign during exercise testing with coexisting impaired diastolic function of the left ventricle (LV) at these patients. METHODS: We formed a cohort of 237 nonconsecutive patients (140 males, 41 +/- 5 years old) having undergone a treadmill test, according to the Bruce protocol, which divided into 2 groups: group A, including 130 patients which presented ST-segment hump sign at any of the leads of the electrocardiograms recorded during exercise, and group B, including 107 patients that didn't. All patients subsequently underwent an echocardiographic estimation of the LV diastolic function, using conventional and Tissue Doppler Imaging techniques. RESULTS: From 237 patients included in our study, 106 had echocardiographic signs of diastolic LV dysfunction. Among them, the appearance of ST hump sign at the peak of exercise testing was observed in 93 patients (88%), particularly in the inferior and lateral leads, while no ST hump sign was observed only in 13 patients (12%) with impaired diastolic LV function. CONCLUSIONS: The appearance of ST segment hump sign during exercise testing is strongly correlated with diastolic LV dysfunction and can be used as an exercise electrocardiographic index of diastolic LV dysfunction, independently from the echocardiographic study.

Tousoulis D, Koumallos N, Antoniades C, Antonopoulos AS, Bakogiannis C, Milliou A, Marinou K, Kallikazarou E, Stefanadi E, Mentzikof D, Stefanadis C. 2010. Genetic polymorphism on type 2 receptor of angiotensin II, modifies cardiovascular risk and systemic inflammation in hypertensive males. Am J Hypertens, 23 (3), pp. 237-242. | Show Abstract | Read more

BACKGROUND: Angiotensin type 2 receptor (AT2R), plays a crucial role in blood pressure regulation and atherogenesis. AT2R gene is located on chromosome X and the biological effect of polymorphism A1675G in this gene needs to be further specified. We examined the impact of A1675G on the risk and the severity of coronary artery disease (CAD), and the expression of proatherogenic inflammatory molecules in hypertensive patients. METHODS: The study population consisted of 146 with CAD (102 with hypertension) and 266 age-matched individuals without CAD (114 with hypertension). The presence of A1675G polymorphism on AT2R gene was determined by PCR. Serum levels of C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured in all the participants. RESULTS: The G allele was associated with decreased risk of CAD among hypertensives (odds ratio (OR) (95% confidence interval (CI))): 0.4 (0.2-0.9), P = 0.01) and less aggressive angiographic CAD (P < 0.001). The G allele was associated with lower IL-6 (median (25-75th percentile): 1.4 (0.6-3.8)), sVCAM-1 (621 (476-799)), CRP (1.2 (0.6-1.7)), and fibrinogen (369 (320-416)) vs. A allele (IL-6: 2.4 (1.1-4.5) P < 0.01, sVCAM-1: 702 (548-925) P < 0.05, CRP: 3.5 (2.0-6.1) P < 0.001, and fibrinogen: 407 (348-514) P < 0.01). The effect of A1675G on serum IL-6, sVCAM-1, and fibrinogen was driven by its effect among hypertensives (IL-6 3.1 (2.1-5.6 in A vs. 1.2 (0.3-3.4) in G P < 0.001, sVCAM-1: 890 (560-1000) in A vs. 556 (377-788) in G P < 0.01, and fibrinogen: 408 (354-510) in A vs. 369 (324-418) in G P < 0.001) whereas it had no effect among nonhypertensives. CONCLUSIONS: Genetic polymorphism A1675G on AT2R gene affects cardiovascular risk and the severity of atherosclerosis by modifying systemic inflammation, especially in hypertensive males.

Tousoulis D, Papageorgiou N, Antoniades C, Giolis A, Bouras G, Gounari P, Stefanadi E, Miliou A, Psaltopoulou T, Stefanadis C. 2010. Acute effects of different types of oil consumption on endothelial function, oxidative stress status and vascular inflammation in healthy volunteers. Br J Nutr, 103 (1), pp. 43-49. | Show Abstract | Read more

Consumption of different types of oil may have different effects on cardiovascular risk. The exact role of maize oil, cod liver oil, soya oil and extra virgin olive oil on endothelial function, oxidative stress and inflammation is unknown. We evaluated the effect of acute consumption of these types of oil on endothelial function, oxidative stress and inflammation in healthy adults. Thirty-seven healthy volunteers were randomised to receive an oral amount of each type of oil or water. Endothelial function was evaluated by gauge-strain plethysmography at baseline and 1, 2 and 3 h after consumption. Oxidative stress status was determined by total lipid peroxides (PEROX), while inflammatory process was estimated by measuring the soluble form of vascular adhesion molecule 1. Serum levels of the two previous markers were measured at baseline and 3 h after oil consumption. Reactive hyperaemia (RH) was significantly decreased after maize oil consumption compared with controls (P < 0.05). However, the consumption of cod liver oil and soya oil induced a significant improvement of RH after 1 h, compared with controls (P < 0.05). There was no significant effect of any type of oil consumption on endothelium-independent dilatation, total lipid PEROX and vascular adhesion molecule 1 serum levels. Consumption of maize oil leads to impaired endothelial function, while soya oil and cod liver oil slightly improve endothelial function. However, all types of oils did not affect inflammatory process and systemic oxidative stress, suggesting that their effect on endothelial function may not be mediated by free radicals bioavailability.

Tousoulis D, Andreou I, Antoniades C, Siasos G, Stougiannos P, Trikas A, Stefanadis C. 2010. Do endothelial progenitor cells modify our strategy to treat risk factors? International Journal of Cardiology,

Michaelides AP, Liakos CI, Antoniades C, Tsiachris DL, Soulis D, Dilaveris PE, Tsioufis KP, Stefanadis CI. 2010. ST-Segment Depression in Hyperventilation Indicates a False Positive Exercise Test in Patients with Mitral Valve Prolapse. Cardiol Res Pract, 2010 (1), pp. 541781. | Show Abstract | Read more

Objectives. Mitral valve prolapse (MVP) is a known cause for false positive exercise test (ET). The purpose of this study was to establish additional electrocardiographic criteria to distinguish the false positive exercise results in patients with MVP. Methods. We studied 218 consecutive patients (53 ± 6 years, 103 males) with MVP (according to echocardiographic study), and positive treadmill ET was performed due to multiple cardiovascular risk factors or angina-like symptoms. A coronary angiography was performed to detect coronary artery disease (CAD). Results. From 218 patients, 90 (group A) presented with normal coronary arteries according to the angiography (false positive ET) while the rest 128 (group B) presented with CAD. ST-segment depression in hyperventilation phase was present in 54 patients of group A (60%) while only in 14 patients of group B (11%), P < .05. Conclusions. Presence of ST-segment depression in hyperventilation phase favors a false positive ET in patients with MVP.

Tousoulis D, Papageorgiou N, Briasoulis A, Antoniades C, Stefanadis C. 2010. The failure of immunomodulation therapy in heart failure: does the statins "paradigm" prove the rule? Curr Vasc Pharmacol, 8 (1), pp. 114-121. | Show Abstract | Read more

Inflammation is an important process and an underlying mechanism involved in atherogenesis as well as the clinical manifestations following coronary artery disease (CAD). Evidence suggests that chronic heart failure (CHF) is associated with an increased inflammatory process. Pro-inflammatory cytokines such as tumor necrosis factor alpha (TNF-a), interleukin-6 (IL-6), interleukin-1 (IL-1) and adhesion molecules are elevated in states of CHF and are related to long term prognosis. Statins are among the most effective compounds reducing morbidity and mortality in patients with, or at increased risk of, CAD. Efficacy and safety of statin treatment has not been validated in patients with CHF. Several studies have reported that statins could be beneficial in patients with CHF. In addition, the beneficial effects of statins have been largely attributed to their anti-inflammatory properties. However, recent randomized, double-blind, placebo-controlled trials reported that statins did not affect clinical outcomes in patients with CHF of any cause. These data support the notion that current immunomodulation approaches in heart failure are not successful. Thus, more large scale clinical trials are required to evaluate the impact of statins on immune imbalance and its restoration in patients with CHF.

Antoniades C, Van-Assche T, Shirodaria C, Diesch J, Antonopoulos AS, Lee J, Cunnington C, Tousoulis D, Stefanadis C, Casadei B et al. 2009. Preoperative sCD40L levels predict risk of atrial fibrillation after off-pump coronary artery bypass graft surgery. Circulation, 120 (11 Suppl), pp. S170-S176. | Show Abstract | Read more

BACKGROUND: The risk of atrial fibrillation (AF) after coronary bypass surgery has been related to redox state, inflammation, and ischemia. Platelet activation is common to all of these pathways. We investigated the relation between AF and preoperative soluble CD40 ligand (sCD40L), a proinflammatory marker released by activated platelets. Furthermore, we studied the role of inflammation, endothelial function, and redox state in this relation. METHODS AND RESULTS: sCD40L levels were measured in 144 patients in sinus rhythm the day before off-pump coronary artery surgery. Systemic inflammation was assessed from levels of C-reactive protein and soluble intercellular adhesion molecule-1, and endothelial function was assessed from the brachial artery flow-mediated dilatation response. Graft samples were collected during surgery to assess vascular redox state. AF occurred in 33% of patients after surgery, with 3% still in AF after 6 weeks. Preoperative sCD40L levels were significantly higher in those who developed in-hospital AF (odds ratio for a 1-SD increase in log[sCD40L]=1.97; 95% CI, 1.21 to 3.22; P=0.007; after adjustment for age, sex, Euroscore, and total duration of operation). sCD40L and vascular superoxide levels were higher in patients still in AF at 6 weeks, and endothelial function was lower, although the small number of events precluded statistical analysis in this group. Systemic endothelial function, redox state, and preoperative markers of systemic inflammation were not associated with in-hospital postoperative AF. CONCLUSIONS: Preoperative platelet activation, as assessed by sCD40L levels, is a novel predictor of postoperative AF, independent of systemic endothelial function, vascular redox state, and systemic inflammation.

Michaelides AP, Liakos CI, Raftopoulos LG, Antoniades C, Vyssoulis G, Andrikopoulos G, Ioakeimides N, Tsioufis C, Soulis D, Stefanadis C. 2009. Electrocardiographic criteria for detecting coronary artery disease in hypertensive patients with ST-segment changes during exercise testing. J Electrocardiol, 42 (5), pp. 405-409. | Show Abstract | Read more

PURPOSE: It is well known that patients with arterial hypertension frequently present with ischemic electrocardiographic changes during exercise testing without actually having coronary artery disease (CAD). The purpose of this study was to establish additional electrocardiographic criteria during exercise testing for detecting CAD in hypertensive patients with ischemic ST-segment response. METHODS: Three hundred eighty-two consecutive hypertensive patients (224 males, 58 +/- 8 years) who presented with ischemic electrocardiographic changes during exercise testing and agreed to undergo coronary arteriography were included in the study. RESULTS: From 382 hypertensive patients undergoing coronary angiography, only 76 (20%) had significant coronary stenosis, whereas 306 (80%) had normal coronary arteries. From 382 patients, 287 (75%) (group A) presented with ST-segment depression during exercise in leads II-III-aVF-V(6), 271 (94%) of which had normal arteries at the angiography. The remaining 95 patients (25%) (group B) of the studied patients presented with ST-segment depression in II-III-aVF and/or V(4) through V(6), 60 (63%) of which had CAD. Furthermore, 251 patients of group A presented with ST-segment depression during the fourth to sixth minute of the recovery period in V(4) through V(6), 247 (98%) of which had normal arteries. Another 28 patients from group B presented with ST-segment depression during the fourth to eighth minute of the recovery period in V(4) through V(6), 22 (79%) of which had significant coronary artery stenosis. CONCLUSIONS: Hypertensive patients who present with ST-segment depression during exercise in leads II-III-aVF and/or V(4) through V(6) and with a prolonged duration of this depression at the recovery phase (fourth to eighth minute) are more likely to have CAD. Absence of ST-segment depression in V(4) and V(5) at the end of exercise or during the seventh and eighth minute of recovery favors a false-positive result.

Tousoulis D, Zisimos K, Antoniades C, Stefanadi E, Siasos G, Tsioufis C, Papageorgiou N, Vavouranakis E, Vlachopoulos C, Stefanadis C. 2009. Oxidative stress and inflammatory process in patients with atrial fibrillation: the role of left atrium distension. Int J Cardiol, 136 (3), pp. 258-262. | Show Abstract | Read more

BACKGROUND: Atrial fibrillation has been associated with increased oxidative stress, elevated inflammatory status and endothelial dysfunction. However, the underlying mechanisms regulating the expression of inflammatory markers or oxidative stress status are unclear. We searched for clinical determinants of oxidative stress status, endothelial function and inflammatory process in patients with chronic atrial fibrillation. METHODS: Sixty nine patients with chronic atrial fibrillation at a stable clinical state were recruited. Ejection fraction of the left ventricle and the dimensions of the left atrium were determined echocardiographically. Flow mediated dilatation (FMD) was evaluated in the brachial artery, while serum oxidized LDL (ox-LDL), matrix metalloproteinase-9 (MMP-9), soluble CD40-ligand (sCD40L) and C-reactive protein (CRP) were measured. RESULTS: FMD was correlated with CRP (r=-0.423, p=0.028), independently of other clinical parameters (beta(SE): -0.0039(0.00159), p=0.022). Ox-LDL was significantly correlated with left atrium diameter(r=0.358, p=0.005) independently of other clinical variables (beta(SE):1.288(0.455), p=0.007). The only independent predictors of MMP-9 were sCD40L (beta(SE):17.232(7.654), p=0.028), CRP (beta(SE):4.249(2.186), p=0.05) and gender (beta(SE):204.657(68.153), p=0.004), but not left atrium dimensions. Independent predictors of CRP were hypertension (beta(SE): 8.531(3.973), p=0.036), sCD40L (beta(SE): 0.779(0.408), p=0.06) and age (beta(SE): 0.381(0.201), p=0.063). CONCLUSIONS: There is a strong link between inflammation and endothelial function, in patients with atrial fibrillation. The maximum diameter of left atrium is the only independent predictor of oxidized LDL, suggesting that left atrium distension may predict oxidative stress status in these patients.

Antoniades C, Bakogiannis C, Tousoulis D, Antonopoulos AS, Stefanadis C. 2009. The CD40/CD40 ligand system: linking inflammation with atherothrombosis. J Am Coll Cardiol, 54 (8), pp. 669-677. | Show Abstract | Read more

The role of CD40/CD40 ligand (CD40L) in atherothrombosis is now widely accepted. However, the exact mechanisms linking the CD40/CD40L system and the soluble form of CD40 ligand (sCD40L) with atherothrombosis are currently a topic of intensive research. CD40L and sCD40L belong to the tumor necrosis factor superfamily, and they are molecules with a dual prothrombotic and proinflammatory role. They are expressed in a variety of tissues such as the immune system (in both B and T cells), the vascular wall, and activated platelets. Soluble CD40L has multiple autocrine, paracrine, and endocrine actions, and it may trigger key mechanisms participating in atherothrombosis. CD40/CD40L may participate in the development of coronary atherosclerosis and the triggering of acute coronary syndromes, while sCD40L seems to have a prognostic role not only in subjects with advanced atherosclerosis but also in the general population. Although conventional cardiovascular medication such as antiplatelet therapy, statins, angiotensin-converting enzyme inhibitors, and many others have been shown to reduce both sCD40L and cardiovascular risk, it is still unclear whether specific treatments targeting the CD40/CD40L system will prove to be beneficial against atherothrombosis in the near future.

Michaelides AP, Andrikopoulos GK, Antoniades C, Soulis D, Tzeis S, Hatzistamatiou E, Tzannos K, Fourlas C, Seferlis C, Stefanadis CI. 2009. Duration of treadmill exercise testing combined with QRS score predicts adverse cardiac outcome at long-term follow-up. Coron Artery Dis, 20 (5), pp. 337-342. | Show Abstract | Read more

OBJECTIVE: Total exercise duration and abnormal QRS score values are treadmill exercise testing (TET) prognostic parameters that have been shown to be significantly and independently associated with cardiac mortality. We evaluated the prognostic value of a new index (M score, Michaelides score) incorporating TET duration and QRS score values in a simple index. METHODS: In this study, we included 626 patients, who underwent TET and coronary arteriography. Cardiac catheterization showed the presence of coronary artery disease in 64.3% of these patients. The M score was calculated by adding the value of the Athens QRS score to the duration of TET (in minutes). The outcome measure was a composite of myocardial infarction or death. Patients were prospectively followed for 38+/-21 months (median 36 months). RESULTS: The composite endpoint was more frequent among the patients of the 1st quartile (M-score values <-5.8). In univariate analysis, mortality of the first-quartile patients was significantly higher (14 vs. 1.1%, P<0.001). In multivariate Cox's regression analysis for age, sex, diabetes, smoking status, hypertension, hypercholesterolemia, maximum ST depression at TET, angina during TET, coronary artery disease on angiography, and echocardiographic left ventricular ejection fraction, the first quartile of M-score values was found to be independently associated with the composite endpoint (relative risk = 3.26, 95% confidence interval = 2.01-5.29, P<0.001). CONCLUSION: This study shows that a new index termed the M score, which incorporates QRS score and exercise duration, predicts mortality and occurrence of myocardial infarction at long-term follow-up of high-risk individuals, independently of TET-induced ST-segment changes.

Koumallos N, Antoniades C, Antonopoulos AS, Tousoulis D, Androulakis A, Psarros T, Stefanadis C. 2009. A rare case of primary cardiac lymphoma presented as superior vena cava syndrome. J Am Coll Cardiol, 54 (4), pp. 368. | Read more

Kampoli AM, Tousoulis D, Antoniades C, Siasos G, Stefanadis C. 2009. Biomarkers of premature atherosclerosis. Trends Mol Med, 15 (7), pp. 323-332. | Show Abstract | Read more

C-reactive protein (CRP) is an acute phase protein and a biochemical marker with important prognostic value for cardiovascular events. Interleukins IL-1 and IL-6 are implicated in the pathogenesis of atherosclerosis and are associated with CRP. Apolipoproteins ApoA-I and ApoB are the main lipid metabolic markers implicated in the development and progression of atherosclerosis. Fibrinogen has also been proposed to be a major independent risk factor for cardiovascular events. Because premature atherosclerosis precedes the development of cardiovascular disease, identification of the associated biomarkers is of great importance. However, further studies will be needed to determine whether or not these markers are useful predictors of future cardiovascular events. Here, we review the roles of specific biomarkers that have been implicated in premature atherosclerosis.

Charakida M, Tousoulis D, Skoumas I, Pitsavos C, Vasiliadou C, Stefanadi E, Antoniades C, Latsios G, Siasos G, Stefanadis C. 2009. Inflammatory and thrombotic processes are associated with vascular dysfunction in children with familial hypercholesterolemia. Atherosclerosis, 204 (2), pp. 532-537. | Show Abstract | Read more

BACKGROUND: Evidence suggests that children with familial hypercholesterolemia (FH) have endothelial dysfunction. Inflammatory and haemostatic abnormalities are associated with advanced atherosclerosis and increased cardiovascular events. However, it is unknown whether these abnormalities present in FH children and contribute to their vascular dysfunction. METHODS AND RESULTS: We studied 38 children with FH (19 males, 19 females aged 14.8+/-0.9 years mean+/-S.E.) and 41 healthy children (controls; 22 males, 19 females aged 15.4+/-0.7 years). Endothelium-dependent reactive hyperemia (RH%) and endothelium-independent nitrate hyperemia dilatation (NH%) were measured by strain gauge plethysmography. Inflammatory and haemostatic parameters were assessed by ELISA. RH% and NH% were significantly reduced in FH compared to controls (91.3+/-9.3% vs. 120.4+/-10.6% and 53.6+/-3.8% vs. 74.5+/-7.4%, p<0.05 for both). Total cholesterol and lipoprotein (a) were increased in FH children compared to controls (282.3+/-8.8 mg/dl vs. 163.8+/-4.6 mg/dl and 11.0[4.6, 30.7]mg/dl vs. 5.24[2.63, 11.0]mg/dl median [IQR] respectively; p<0.001 for both). Intercellular cell adhesion molecule (ICAM-1) and interleukin 1 beta (IL-1 beta) serum levels were increased in FH compared to controls (p<0.05 and <0.001, respectively). Plasminogen activator inhibitor 1 (PAI-1) levels were also higher in FH children (p<0.001). Multivariate analysis revealed that reactive hyperemia was independently associated with nitrate-dependent reactive hyperemia (beta=0.597(0.199), p<0.01), PAI-1(beta=-6.78(2.65), p<0.05), log IL-1 beta (beta=-102.8 (30.2), p<0.01), age (beta=-5.06 (2.35), p<0.05) and FH status (beta=-25.2(10.6), p<0.05) (R(2) for the model: 0.63, p=0.001). CONCLUSIONS: Inflammatory and haemostatic abnormalities are present in FH children and contribute to the endothelial dysfunction observed in these children.

Antonopoulos AS, Antoniades C, Tousoulis D, Bakogiannis C, Demosthenous M, Psarros C, Stefanadis C. 2009. Novel therapeutic strategies targeting vascular redox in human atherosclerosis. Recent Pat Cardiovasc Drug Discov, 4 (2), pp. 76-87. | Show Abstract | Read more

It is now widely accepted that redox signaling is a key feature in vascular homeostasis. Reactive oxygen species are generated by a wide range of enzymatic systems located in both vascular endothelium and vascular wall. Further, to their role as cytotoxic molecules produced by immune system, free radicals play critical signaling roles in the vascular wall. By regulating several redox-sensitive transcription pathways, free radicals play a key role in the synthesis of inflammatory mediators in both vascular endothelium and vascular wall, with important role in the overall vascular dysfunction. The well-established role of redox state in vascular disease mandates that development of newer therapeutic strategies should be able to alter redox-sensitive intracellular signaling events. Widely used cardiovascular agents like statins or angiotensin receptor blockers have well documented beneficial effects on vascular redox state, reflected also in clinical outcome improvement. Newer promising strategies along with recent patented inventions may also include thiazolidinediones, folates, tetrahydrobiopterin, cyclopentone prostaglandins and aldose reductase inhibitors with well known effects on vascular redox, but with still unclear results on clinical outcome. Better understanding of redox-sensitive intracellular signaling pathways could indicate the critical steps to intervene with newer agents to reverse vascular dysfunction, inhibiting atherosclerosis progression and potentially improve clinical outcome.

Siasos G, Tousoulis D, Vlachopoulos C, Antoniades C, Stefanadi E, Ioakeimidis N, Zisimos K, Siasou Z, Papavassiliou AG, Stefanadis C. 2009. The impact of oral L-arginine supplementation on acute smoking-induced endothelial injury and arterial performance. Am J Hypertens, 22 (6), pp. 586-592. | Show Abstract | Read more

BACKGROUND: Smoking is associated with endothelial dysfunction and increased inflammatory status. The amino acid L-arginine, improves endothelial function in patients with cardiovascular risk factors. We investigated the effect of L-arginine on vascular function and inflammatory process in healthy smokers at rest and after acute smoking. METHODS: We studied the effect of L-arginine and/or placebo in 12 healthy young smokers on three occasions (day 0, day 1, and day 3). The study was carried out on two separate arms, one with L-arginine (3 x 7 g/day) and one with placebo, according to a randomized, placebo-controlled, double-blind, cross-over design. Measurements were carried out before, immediately after, and 20 min after cigarette smoking. Endothelial function was evaluated by flow-mediated dilation (FMD). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) and as a measure of arterial wave reflections. Serum soluble intercellular adhesion molecule-1 (sICAM-1) was measured. RESULTS: Compared to placebo, L-arginine improved FMD (P < 0.01 at day 1 and P < 0.05 at day 3). L-Arginine reduced PWV and AIx at both days 1 and 3 (P < 0.05 vs. baseline). L-Arginine blunted the acute smoking-induced increase of AIx at both day 1 (P < 0.05) and day 3 (P < 0.01), and prevented the smoking-induced elevation of PWV at day 3 (P < 0.05). Importantly, L-arginine reduced sICAM-1 at days 1 and 3 (P < 0.05 for both vs. baseline). CONCLUSIONS: Oral L-arginine improves endothelial function and vascular elastic properties of the arterial tree during the acute phase of smoking, an effect accompanied by reduced sICAM-1 levels in these subjects.

Tousoulis D, Drolias A, Antoniades C, Vasiliadou C, Marinou K, Latsios G, Stefanadi E, Gounari P, Siasos G, Papageorgiou N et al. 2009. Antidepressive treatment as a modulator of inflammatory process in patients with heart failure: effects on proinflammatory cytokines and acute phase protein levels. Int J Cardiol, 134 (2), pp. 238-243. | Show Abstract | Read more

BACKGROUND: Depression has been associated with increased inflammatory process. Although anti-depressive medication has anti-inflammatory effect in major depression, its role in patients with heart failure (HF) is unknown. In the present study we evaluated the impact of antidepressive medication on the expression of proinflammatory cytokines and acute phase response proteins, in patients with HF and major depression. METHODS: The study population consisted of 250 patients with HF (154 suffering from major depression). Patients with major depression were under selective serotonin reuptake inhibitors (SSRIs, n=120) or tricyclic antidepressants (TCA) and/or serotonin/norepinephrine reuptake inhibitors (SNRIs) (n=34), for at least 6 months. RESULTS: Levels of TNF-alpha, IL-6, CRP and fibrinogen were not significantly different between HF patients with depression under treatment and those without depression (p=NS for all). However, TNF-alpha and CRP levels were significantly lower in patients receiving TCA/SNRI compared to patients receiving SSRIs or those without depression (p<0.05 for all). Similarly, patients under TCA/SNRI had significantly lower heart rate compared to those treated with SSRIs or those without depression. In multivariate analysis, treatment with SNRI/TCA was an independent predictor for log(TNF-alpha) (beta=0.036(SE:0.016) and log(CRP) (beta=0.099(SE:0.048), p=0.041). CONCLUSIONS: In the present study we demonstrate for the first time that treatment of patients with HF and major depression with TCAs/SNRIs, is associated with lower levels of TNF-alpha and CRP, suggesting that the type of antidepressive treatment may have a significant effect on the underlying inflammatory process.

Pitsavos C, Skoumas I, Tousoulis D, Metalinos G, Masoura C, Chrysohoou C, Papadimitriou L, Giotsas N, Toutouza M, Antoniades C, Stefanadis C. 2009. The impact of ezetimibe and high-dose of statin treatment on LDL levels in patients with heterozygous familial hypercholesterolemia. Int J Cardiol, 134 (2), pp. 280-281. | Show Abstract | Read more

We evaluated the efficacy and the safety of combining high doses of statins and ezetimibe in heterozygous familial hypercholesterolemia (hFH) patients. Seventy patients with hFH, received 10 mg of ezetimibe, in addition to their current statin therapy and were followed up for twelve months. The co-administration of statins and ezetimibe improved total cholesterol (p<0.05), LDL-c(p<0.05), triglycerides (p<0.05) and apolipoprotein-B (p<0.05) in comparison to statin monotherapy. There were no changes in high density lipoprotein cholesterol (HDL-c), apolipoprotein-A, lipoprotein (a), fibrinogen and C-reactive protein (CPR). In conclusion the combination of 10 mg of ezetimibe with high dose statin therapy is effective in hFH, offering a further reduction of LDL-c throughout the 12 months of follow up.

Antoniades C, Shirodaria C, Leeson P, Baarholm OA, Van-Assche T, Cunnington C, Pillai R, Ratnatunga C, Tousoulis D, Stefanadis C et al. 2009. MTHFR 677 C>T Polymorphism reveals functional importance for 5-methyltetrahydrofolate, not homocysteine, in regulation of vascular redox state and endothelial function in human atherosclerosis. Circulation, 119 (18), pp. 2507-2515. | Show Abstract | Read more

BACKGROUND: The role of circulating homocysteine as an atherosclerosis risk factor has recently been questioned. However, 5-methyl-tetrahydrofolate (5-MTHF), the circulating metabolite of folic acid participating in homocysteine metabolism, has direct effects on vascular function. We sought to distinguish the effects of plasma versus vascular tissue 5-MTHF and homocysteine on vascular redox and endothelial nitric oxide bioavailability in human vessels. METHODS AND RESULTS: We used the methyl tetrahydrofolate reductase (MTHFR) gene polymorphism 677C>T as a model of chronic exposure of the vascular wall to varying 5-MTHF levels in 218 patients undergoing coronary artery bypass graft surgery. Vascular superoxide, vascular 5-MTHF, and total homocysteine were determined in saphenous veins and internal mammary arteries obtained during surgery. Nitric oxide bioavailability was evaluated by organ bath studies on saphenous vein rings. MTHFR genotype was a determinant of vascular 5-MTHF (not vascular homocysteine). Both MTHFR genotype and vascular 5-MTHF were associated with vascular nitric oxide bioavailability and superoxide generated by uncoupled endothelial nitric oxide synthase. In contrast, vascular homocysteine was associated only with NADPH-stimulated superoxide. CONCLUSIONS: Genetic polymorphism 677 C>T on MTHFR affects vascular 5-MTHF (but not homocysteine) and can be used as a model to distinguish the chronic effects of vascular 5-MTHF from homocysteine on vascular wall. Vascular 5-MTHF, rather than plasma or vascular homocysteine, is a key regulator of endothelial nitric oxide synthase coupling and nitric oxide bioavailability in human vessels, suggesting that plasma homocysteine is an indirect marker of 5-MTHF rather than a primary regulator of endothelial function.

Antoniades C, Antonopoulos AS, Tousoulis D, Stefanadis C. 2009. Adiponectin: from obesity to cardiovascular disease. Obes Rev, 10 (3), pp. 269-279. | Show Abstract | Read more

Adiponectin is an adipokine whose biosynthesis is deranged in obesity and diabetes mellitus, predisposing to atherosclerosis. Evidence suggests that adiponectin has anti-atherogenic properties by improving endothelial function and having anti-inflammatory effects in the vascular wall. In addition, adiponectin modifies vascular intracellular redox signalling and exerts indirect antioxidant effects on human myocardium. However, its clinical role in cardiovascular disease is obscure. Adiponectin's positive prognostic value in coronary artery disease had been widely supported over the last years, but this view has been questioned recently. High adiponectin levels are paradoxically associated with poorer prognosis in heart failure syndrome. These controversial findings seem surprising as adiponectin has been viewed overall as an anti-atherogenic molecule. Therefore, any certain conclusion about adiponectin's role in cardiovascular disease seems premature. Despite the rapidly accumulating literature on this adipokine, it is still unclear whether adiponectin is a key mediator or a bystander in cardiovascular disease. It is still uncertain whether adiponectin levels have any clinical significance for risk stratification in cardiovascular disease or they just reflect the activation of complex and opposing underlying mechanisms. Circulating adiponectin levels should be interpreted with caution, as they may have completely different prognostic value, depending on the underlying disease state.

Antoniades C, Shirodaria C, Leeson P, Antonopoulos A, Warrick N, Van-Assche T, Cunnington C, Tousoulis D, Pillai R, Ratnatunga C et al. 2009. Association of plasma asymmetrical dimethylarginine (ADMA) with elevated vascular superoxide production and endothelial nitric oxide synthase uncoupling: implications for endothelial function in human atherosclerosis. Eur Heart J, 30 (9), pp. 1142-1150. | Show Abstract | Read more

BACKGROUND: Asymmetrical dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide synthase (eNOS), is considered to be a risk factor for atherosclerosis. However, the mechanisms relating ADMA with vascular function have been evaluated in vitro and in animal models, but its effect in human vasculature is unclear. AIMS: We examined the impact of serum ADMA on endothelial nitric oxide (NO) bioavailability and vascular superoxide radical (O2-) production in patients with advanced atherosclerosis. METHODS AND RESULTS: Paired samples of saphenous veins (SVs) and internal mammary arteries (IMAs) were collected from 201 patients undergoing coronary bypass surgery, and serum ADMA was measured pre-operatively. The vasomotor responses of SV segments to acetylcholine (ACh) and bradykinin (Bk) were evaluated ex vivo. Vascular O2- was measured in paired SV and IMA by lucigenin-enhanced chemiluminescence. The l-NAME-inhibitable as well as the NADPH-stimulated vascular O2- generation was also determined by chemiluminescence. High serum ADMA levels were associated with decreased vasorelaxation of SV to ACh (P < 0.05) and Bk (P < 0.05). Similarly, high serum ADMA was associated with higher total O2- production in both SVs and IMAs (P < 0.05) and greater L-NAME-inhibitable vascular O2- (P < 0.05). However, serum ADMA was not associated with NADPH-stimulated vascular O2-. In multivariable linear regression, serum ADMA was independently associated with vascular O2- in both SVs [beta (SE): 0.987 (0.412), P = 0.019] and IMAs [beta (SE): 1.905 (0.541), P = 0.001]. Asymmetrical dimethylarginine was also independently associated with maximum vasorelaxation in response to both ACh [beta (SE): 14.252 (3.976), P = 0.001] and Bk [beta (SE): 9.564 (3.762), P = 0.013]. CONCLUSION: This is the first study that demonstrates an association between ADMA and important measures of vascular function, such as vascular O2- production and NO bioavailability directly in human vessels. Although serum ADMA has no effect on NADPH-stimulated superoxide in intact vessels, it is associated with greater eNOS uncoupling in the human vascular endothelium of patients with coronary artery disease.

Tousoulis D, Briasoulis A, Dhamrait SS, Antoniades C, Stefanadis C. 2009. Effective platelet inhibition by aspirin and clopidogrel: where are we now? Heart, 95 (10), pp. 850-858. | Read more

Stefanadi E, Tousoulis D, Antoniades C, Katsi V, Bosinakou E, Vavuranakis E, Triantafyllou G, Marinou K, Tsioufis C, Papageorgiou N et al. 2009. Early initiation of low-dose atorvastatin treatment after an acute ST-elevated myocardial infarction, decreases inflammatory process and prevents endothelial injury and activation. Int J Cardiol, 133 (2), pp. 266-268. | Show Abstract | Read more

BACKGROUND: High-dose statin treatment improves clinical outcome of ST-elevated myocardial infarction (STEMI). However, the effect of low-dose atorvastatin treatment on inflammatory and pro-thrombotic molecules during the post-STEMI period is unclear. We investigated the effect of low-dose atorvastatin treatment on the kinetics of cytokine IL-6, vascular cell adhesion molecule (sVCAM-1) and endothelium-derived markers of thrombosis/fibrinolysis such as von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA), post STEMI. METHODS: Twenty-four normocholesterolemic patients with STEMI were randomised to receive atorvastatin 10mg/day or no statin treatment for 6 weeks after the event. Blood samples were obtained by their admission to the hospital as well as at weeks 1 and 6. Circulating levels of IL-6, sVCAM-1, vWF, PAI-1 and tPA were determined by ELISA. RESULTS: Atorvastatin induced a decrease of IL-6 at 1 week, an effect which reached significance compared to baseline at 6 weeks post STEMI (p<0.05 vs baseline). Serum sVCAM-1 was increased in controls both at 1 and 6 weeks post-STEMI (p<0.05 vs baseline), an effect prevented by atorvastatin. Plasma vWF was increased 1 week post-STEMI in controls (p<0.05 vs baseline) and returned to baseline at 6 weeks, an effect prevented by atorvastatin. Plasma PAI-1, tPA and the PAI-1/tPA ratio remained unchanged in both groups. CONCLUSION: Early initiation of low-dose atorvastatin treatment decreases the expression of IL-6 and sVCAM-1 and the release of vWF in patients with STEMI. Therefore, low-dose atorvastatin, modulates inflammatory response and decreases endothelial injury and activation in patients with recent STEMI.

Michaelides AP, Stamatopoulos I, Antoniades C, Anastasakis A, Kotsiopoulou C, Theopistou A, Misailidou M, Fourlas C, Elliott PM, Stefanadis C. 2009. ST segment "hump" during exercise testing and the risk of sudden cardiac death in patients with hypertrophic cardiomyopathy. Ann Noninvasive Electrocardiol, 14 (2), pp. 158-164. | Show Abstract | Read more

BACKGROUND: The appearance of a discrete upward deflection of the ST segment termed "the ST hump sign" (STHS) during exercise testing has been associated with resting hypertension and exaggerated blood pressure response to exercise. OBJECTIVE: We investigated the prevalence and clinical significance of this sign in a population of patients with hypertrophic cardiomyopathy. METHODS: Eighty-one patients with hypertrophic cardiomyopathy (HCM) who underwent cardiopulmonary exercise testing were followed in a retrospective cohort study for a mean period of 5.3 years. RESULTS: The appearance of the STHS at the peak of exercise testing was observed in 42 patients (52%), particularly in the inferior and the lateral leads. Patients with the STHS had higher fractional shortening and maximum left ventricular wall thickness and exhibited more frequently outflow tract gradient >30 mmHg at rest. Furthermore, the presence of STHS was a strong independent predictor of the risk of sudden cardiac death (SCD), as the latter occurred in eight of the patients with this sign (8/42, 19%) and in none of the patients without it (0/39, 0%) (P < 0.001). CONCLUSION: The appearance of a "hump" at the ST segment during exercise testing appears to be a risk factor for SCD in patients with HCM. However, further studies are necessary to validate this finding in larger populations and to elucidate the mechanism of the appearance of the "hump."

Antoniades C, Antonopoulos AS, Tousoulis D, Bakogiannis C, Stefanadi E, Stefanadis C. 2009. Relationship between the pharmacokinetics of levosimendan and its effects on cardiovascular system. Curr Drug Metab, 10 (2), pp. 95-103. | Show Abstract | Read more

Levosimendan, a Ca(2+) sensitizer, has emerged as an alternative option of pharmacologic inotropic support in patients with decompensated heart failure. In contrast to classic inotropes, rather than interfering with intracellular Ca(2+) levels in myocytes, levosimendan improves cardiac performance via Ca(2+) sensitization and K(+) channel-mediated peripheral vasodilatation. A two compartment pharmacokinetic model with zero-order input and first-order elimination has been found to describe best the pharmacokinetics of levosimendan. Although oral levosimendan has high bioavailability (approximately equal to 85%), in clinical practice it has been hitherto administered intravenously. Levosimendan has total clearance 175-250 mL/h/kg and most importantly a short half-life (about 1.5 hours). Therefore, this drug has a special pharmacokinetic interest: It is one of the few drugs used in cardiovascular medicine, whose prolonged action is not due to the drug itself but it is mainly due to its active metabolite OR-1896 (approximately 80 hours half life). Other metabolites with possible pharmacologic effect are N-conjugated OR-1855 (M7), N-hydroxylated OR-1855 (M8), N-hydroxylated OR-1896 (M10), O-glucuronide OR-1896 (M9) and O-sulfate (M11) of N-hydroxylated OR-1896. Initial reports on levosimendan's use in severe heart failure were positive and levosimendan has already been routinely used for the treatment of patients with decompensated heart failure, while it has been included to the European Society of Cardiology guidelines for the treatment of acute heart failure (class of recommendation IIb, level of evidence B). However, recent clinical trials have failed to demonstrate a clear benefit of levosimendan on survival, compared to other classic inotropic agents in patients requiring inotropic support. In this review article we provide a pharmacokinetic approach for the use of levosimendan in cardiovascular system by discussing its metabolism and mainly the pharmacology of its active metabolites in humans.

Antoniades C, Mussa S, Shirodaria C, Lee J, Diesch J, Taggart DP, Channon KM, Leeson P. 2009. Relation of preoperative radial artery flow-mediated dilatation to nitric oxide bioavailability in radial artery grafts used in off-pump coronary artery bypass grafting. Am J Cardiol, 103 (2), pp. 216-220. | Show Abstract | Read more

The radial artery is prone to vasospasm after coronary bypass surgery, and endothelial dysfunction is likely to be a key factor. We investigated whether endothelial dysfunction in radial artery conduits is present, and can be identified, preoperatively using a simple noninvasive ultrasound test of radial artery endothelial response, flow-mediated dilatation (FMD). The study population consisted of 126 patients scheduled for coronary artery bypass grafting. The afternoon before operation, patients had noninvasive ultrasound assessment of endothelial function in the left radial artery by FMD, which measures change in arterial size after an increase in flow-an endothelial-dependent response. Surplus graft segments were obtained at operation and nitric oxide bioavailability within the vessels determined from ex vivo responses to acetylcholine. Preoperative FMD in the radial artery was associated with vasorelaxations to acetylcholine in radial artery grafts (p<0.001 for both dose-response curves and maximum relaxations), although there was weak borderline association between FMD and vasorelaxations of saphenous vein grafts (p=0.07 for dose-response curves and p<0.05 for maximum relaxations). In multivariate analysis including cardiac risk factors, FMD was a predictor of vasorelaxations of radial artery grafts (beta=0.020, SE=0.009, p=0.030), independent of classic risk factors for atherosclerosis. In conclusion, there is significant interindividual variation in the endothelial function of vessels used for coronary artery bypass surgery, particularly the radial artery. These differences are present and can be identified preoperatively by FMD.

Tousoulis D, Papageorgiou N, Antoniades C, Tsioufis C, Siasos G, Stefanadis C. 2009. Red wine and vascular endothelium pp. 359-372. | Show Abstract

Light to moderate alcohol consumption may have a beneficial effect on cardiovascular morbidity and mortality. Red wine has been shown to improve endothelial function and decrease oxidative stress. Consumption of red wine induces significant increases in plasma total antioxidant status and significant decreases in plasma malondialdehyde and glutathione in both young and old subjects. Red wine consumption for 2 weeks markedly attenuates insulin-resistance in type 2 diabetic patients, without affecting vascular reactivity and nitric oxide production. In vitro and in animal models, red wine polyphenolics cause substantial falls in blood pressure, mainly by increasing nitric oxide production. Although red wine has beneficial effects on vascular endothelium, more studies are necessary to evaluate these effects on cardiovascular risk. © 2009 by Nova Science Publishers, Inc. All rights reserved.

Cited:

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Antoniades C, Antonopoulos AS, Tousoulis D, Stefanadis C. 2009. Adiponectin: From obesity to cardiovascular disease: Etiology and Pathophysiology Obesity Reviews, 10 (3), pp. 269-279. | Read more

Tousoulis D, Kampoli AM, Siasos G, Stefanadi E, Antoniades C, Papavassiliou AG, Stefanadis C. 2009. Circulating biomarkers for the diagnosis and prognosis of heart failure. Curr Med Chem, 16 (29), pp. 3828-3840. | Show Abstract | Read more

Despite substantial therapeutic advances, heart failure remains a syndrome associated with high morbidity and mortality. The management of heart failure remains challenging despite the recent different therapeutic advances. The emergence of cardiac biomarkers as increasingly effective clinical tools suggests the potential of a new approach to the management of patients with heart failure. A variety of circulating biomarkers of diagnostic and prognostic utility in heart failure is currently being studies in preclinical, observational and randomized prospective studies. Of the various candidate biomarkers, the greatest wealth of knowledge and clinical experience lies with the B-type naturetic peptides. However, because individual biomarkers may have limited sensitivity and specificity, a multi-marker approach, using combinations of different biomarkers that reflect different aspects of the pathophysiological milieu, would contribute to better risk stratification and optimization of therapy.

Antoniades C, Antonopoulos AS, Tousoulis D, Marinou K, Stefanadis C. 2009. Homocysteine and coronary atherosclerosis: from folate fortification to the recent clinical trials. Eur Heart J, 30 (1), pp. 6-15. | Show Abstract | Read more

Plasma total homocysteine (Hcy) has been associated with cardiovascular risk in multiple large-scale epidemiological studies, and it has been considered as an independent risk factor for atherosclerosis. Homocysteine lowering, achieved after the introduction of the folate food fortification programme in North America, was accompanied by an accelerated decline of cardiovascular risk and especially of stroke. Although the initial clinical trials suggested that homocysteine-lowering treatment with folates and B vitamins induces coronary plaque regression, this finding was not confirmed by more recent clinical studies. Under the light of the findings from the recent large randomized clinical trials that failed to document a benefit of Hcy lowering on clinical outcome of patients with atherosclerosis, the role of Hcy as a risk factor and the efficacy of Hcy lowering against atherosclerosis have been questioned. Therefore, better understanding of the mechanisms relating Hcy and Hcy-lowering treatment with vascular function and atherogenesis is crucial, to help us understand why clinical trials failed to show a benefit from Hcy-lowering treatment. Are these therapeutic strategies ineffective because they fail to reduce intracellular Hcy levels and vascular redox state or should Hcy stop being considered as an independent risk factor for atherosclerosis from now on? In this review article, we provide a global approach of the molecular mechanisms relating Hcy with cardiovascular risk and introduce possible mechanistic explanations regarding the inability of clinical trials to detect any clinical benefit from Hcy-lowering treatment in secondary prevention. Finally, we provide clinical recommendations regarding the therapeutic strategies targeting homocysteine in the general population.

Antoniades C, Antonopoulos AS, Bendall JK, Channon KM. 2009. Targeting redox signaling in the vascular wall: from basic science to clinical practice. Curr Pharm Des, 15 (3), pp. 329-342. | Show Abstract | Read more

Oxidative stress is a key feature in vascular homeostasis. Reactive oxygen species (ROS) are produced by multiple enzymatic sources located in various anatomical structures of the vascular wall, such as the vascular endothelium, the smooth muscle cells and inflammatory cells infiltrating sub-endothelial space and the rest of the vascular wall. Although ROS behave as signaling molecules regulating important aspects of vascular physiology, their excess generation is harmful. Further to the cytotoxic effect of ROS in the vascular wall, they also activate various redox sensitive transcription pathways, regulating the expression of proinflammatory molecules with strong pro-atherogenic effects. The activation of redox-sensitive enzymatic systems in the vascular wall such as matrix metalloproteinases as well as the impairment of endothelial function have a significant impact on vascular elasticity and vascular mechanics in general. The impairment of vascular mechanics has a significant impact on vascular homeostasis, promoting atherogenesis. It is therefore crucial to regulate vascular redox signaling, by developing therapeutic strategies able to target the effectively intracellular ROS bioavailability. Statins, angiotensin converting enzyme inhibitors, thiazolidinediones, folates, tetrahydrobiopterin and other therapeutic strategies seem promising in targeting vascular redox signaling, although it is still unclear which of these treatments have the potential to effectively prevent atherogenesis. Future studies need to define the key redox sensitive pathways in the vascular wall in order to develop effective therapeutic strategies against atherosclerosis.

Tousoulis D, Kampoli AM, Papageorgiou N, Papaoikonomou S, Antoniades C, Stefanadis C. 2009. The impact of diabetes mellitus on coronary artery disease: new therapeutic approaches. Curr Pharm Des, 15 (17), pp. 2037-2048. | Show Abstract | Read more

Patients with diabetes mellitus (DM) type 2 have a high prevalence of coronary artery disease (CAD), as diabetes is implicated in the formation of atherosclerotic plaque. Hyperglycemia, elevated free fatty acid, increased amount of circulating end-glucosylated serum products and insulin resistance are the main mechanisms involved in the accelerated atherosclerotic process observed in type 2 DM patients. Novel treatments have been proposed to prevent and treat CAD in patients with diabetes, mainly in those with diabetes type 2. Several clinical trials have been designed in order to examine the effectiveness of these agents, such as angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers, glitazones, statins and antioxidants, but the results are still controversial.

Briasoulis A, Tousoulis D, Antoniades C, Stefanadis C. 2009. The oxidative stress menace to coronary vasculature: any place for antioxidants? Curr Pharm Des, 15 (26), pp. 3078-3090. | Show Abstract | Read more

Oxidative stress is involved in the pathogenesis of atherosclerosis. A variety of antioxidants has been used in clinical studies, during the past few years, for the prevention and treatment of atherosclerosis. In small clinical studies it was found that both vitamins C and E may improve endothelial function in high risk patients. However, interventional trials have been controversial, with some positive findings, many null findings, and some suggestion of harm in certain high-risk populations. Therefore, treatment with antioxidant vitamins C and E should not be recommended for the prevention or treatment of coronary atherosclerosis. New antioxidant strategies are needed to clarify the exact role of antioxidant treatment in coronary atherosclerosis.

Dima I, Vlachopoulos C, Alexopoulos N, Baou K, Vasiliadou C, Antoniades C, Aznaouridis K, Stefanadi E, Tousoulis D, Stefanadis C. 2008. Association of arterial stiffness with the angiotensin-converting enzyme gene polymorphism in healthy individuals. Am J Hypertens, 21 (12), pp. 1354-1358. | Show Abstract | Read more

BACKGROUND: Arterial stiffness is an important determinant of cardiovascular morbidity and mortality. The I/D polymorphism of angiotensin-converting enzyme (ACE) gene is associated with cardiovascular disease. However, the relationship between ACE polymorphism, arterial stiffness, and wave reflections in healthy, low-risk population has not been defined yet. METHODS: The study included 282 apparently healthy, low-risk individuals (mean age 39.7 +/- 8.9 years, 178 males). Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness, while wave reflections were assessed by augmentation index (AIx) of the central pressure waveform. I/D polymorphism of the ACE gene was determined in all subjects for the prevalence of the DD, ID, and II genotype (39, 44, and 17%, respectively). C-reactive protein (CRP) levels were determined as a marker of chronic, subclinical inflammation. RESULTS: After adjustment for potential confounding factors, presence of D allele was associated with lower values of PWV compared to II genotype (P < 0.05), implying lower aortic stiffness for D allele carriers. There was no association between ACE genotype and wave reflections or peripheral and central systolic pressures. CONCLUSIONS: In apparently healthy individuals, D allele is associated with lower aortic stiffness, whereas there is no association of the ACE polymorphism with wave reflections. This finding provides new insights into the possible links between ACE gene, regulation of large artery stiffness, and has implications for cardiovascular risk.

Tousoulis D, Andreou I, Antoniades C, Tentolouris C, Stefanadis C. 2008. Role of inflammation and oxidative stress in endothelial progenitor cell function and mobilization: therapeutic implications for cardiovascular diseases. Atherosclerosis, 201 (2), pp. 236-247. | Show Abstract | Read more

Endothelial progenitor cells (EPCs) are mobilized from the bone marrow into the peripheral circulation, home to sites of injury, and incorporate into foci of neovascularization, thereby improving blood flow and tissue recovery. Patients with cardiovascular diseases, including coronary artery disease, heart failure, hypertension, and diabetes, have been shown to exhibit reduced number and functional capacity of EPCs. Considerable evidence indicates that EPCs constitute an important endogenous system to maintain endothelial integrity and vascular homeostasis, while reduced number of EPCs has recently been shown to predict future cardiovascular events. Thus, enhancement of EPCs could be of potential benefit for individuals with cardiovascular diseases. The interplay between inflammation and oxidative stress is involved in the initiation, progression, and complications of cardiovascular diseases. Emerging evidence from in vitro and clinical studies suggests that inflammatory and oxidative changes influence EPC mobilization. Drugs with anti-inflammatory and antioxidant properties, currently administered to patients with cardiovascular diseases, such as statins, have been demonstrated to exert beneficial effects on EPC biology. A better understanding of the inflammatory and oxidative mechanisms leading to the numerical and functional impairment of EPCs would provide additional insight into the pathogenesis of cardiovascular disease and create novel therapeutic targets.

Tousoulis D, Kaski JC, Antoniades C, Stefanadis C. 2008. Beneficial effects of statin treatment after myocardial infarction: Is progenitor cell mobilization the missing link? Int J Cardiol, 130 (3), pp. 301-303. | Show Abstract | Read more

It is widely accepted that statin treatment improves survival in patients with myocardial infarction. Evidence also suggests that aggressive statin treatment is superior than standard dose during the post-infarction period. However, the exact mechanisms are still not well understood. Endothelial progenitor cells (EPC) play a key role in vascular homeostasis, since they contribute to the repair of damaged endothelium post-myocardial infarction, while they induce neoangiogenesis. Recent evidence suggests that statins may exert their beneficial effect in patients with recent myocardial infarction, by inducing EPC mobilization, and this may be a key mechanism by which statins improve survival in these patients. However, large scale clinical trials remain to prove that aggressive statin treatment is superior than standard dose in these patients, by inducing a more effective EPC mobilization.

Nikolopoulou A, Tousoulis D, Antoniades C, Petroheilou K, Vasiliadou C, Papageorgiou N, Koniari K, Stefanadi E, Latsios G, Siasos G, Stefanadis C. 2008. Common community infections and the risk for coronary artery disease and acute myocardial infarction: evidence for chronic over-expression of tumor necrosis factor alpha and vascular cells adhesion molecule-1. Int J Cardiol, 130 (2), pp. 246-250. | Show Abstract | Read more

BACKGROUND: Although several common community infections have been associated with the risk for coronary artery disease (CAD), their role in the development of acute myocardial infarction (AMI) is still unclear. We examined the prevalence of IgG and IgM (or IgA) antibodies against common infections such as HSV, Hepatitis A (HAV), Helicobacter pylori (HP), cytomegalovirus (CMV) and Chlamydia pneumoniae (CP), in CAD and AMI patients, and their relationship with pro-atherogenic inflammatory molecules. METHODS: A total number of 337 subjects were included in this study: 150 patients with angiographically documented stable CAD, 138 patients admitted with AMI and 49 healthy individuals. Serum IgG and IgM against HAV, CMV and HSV, IgG against HP and IgG/IgA against CP were determined in all participants. Serum tumor necrosis factor alpha (TNF-alpha) and soluble vascular cells adhesion molecule (sVCAM-1), were determined by ELISA. RESULTS: Patients with CAD were more likely to have anti-HAV IgG (94.4%), anti-HSV IgG (97.2%) and anti-HP IgG (55.1%) compared to healthy individuals (70.8%, 89.6% and 39.6% respectively, p<0.05 for all). In multivariate analysis, anti-HAV IgG was an independent predictor of CAD (beta(SE): 0.187(0.075), p=0.015). Among the CAD patients, the presence of anti-CP IgA was more frequent in those admitted with AMI (39%) compared to those with stable CAD (21%, p<0.05). Finally, both patients and controls had significantly higher levels of sVCAM-1 and TNF-alpha in the presence of anti-HAV IgG, compared to those without anti-HAV IgG (p<0.05 for all). CONCLUSION: Past infections with HAV, HSV and HP are associated with higher risk for coronary atherosclerosis, while the presence of anti-HAV IgG is also associated with higher levels of TNF-alpha and sVCAM-1. Furthermore, the presence of recent infection by CP is associated with higher risk for AMI among CAD patients. These findings are important since they demonstrate that past HAV, HSV and HP infections may affect cardiovascular risk, while recent CP infection may be implicated in the triggering of AMI among CAD patients.

Tousoulis D, Briasoulis A, Papageorgiou N, Antoniades C, Stefanadis C. 2008. Candidate gene polymorphisms and the 9p21 locus in acute coronary syndromes. Trends Mol Med, 14 (10), pp. 441-449. | Show Abstract | Read more

It is now widely accepted that the classic environmental risk factors for atherosclerosis only partly explain the incidence of coronary artery disease and the development of acute coronary syndromes. Therefore, genetic factors that vary among human populations seem to be involved in the clinical manifestations of such patients. Substantial data suggest that a significant proportion of genetic polymorphisms involved in endothelial function, inflammation, lipid metabolism, thrombosis and fibrinolysis are often present in patients with acute coronary syndromes. In particular, a common variant on chromosome 9p21 was recently identified to affect the risk of myocardial infarction. Here, we review the progress of candidate gene studies and genome-wide association studies in identifying the genetic bases of complex cardiovascular diseases such as acute coronary syndromes.

Michaelides AP, Fourlas CA, Andrikopoulos GK, Antoniades C, Soulis D, Chatzistamatiou E, Stefanadis CI. 2008. Correlation of modification of heart rate recovery with adaptation to myocardial ischemia in a model of sequential exercise testings. Ann Noninvasive Electrocardiol, 13 (4), pp. 364-370. | Show Abstract | Read more

BACKGROUND: Heart rate recovery (HRR) has been identified as a reliable predictor of cardiac mortality, correlated with autonomic tone. In a model of sequential exercise testings, we investigated the reproducibility of HRR and the association between HRR modification and myocardial adaptation to ischemia. METHODS: We studied 128 patients (mean age 62 +/- 9 years, 83% males) with angiographically documented coronary artery disease (CAD) and a first positive exercise testing, who agreed to undergo a second exercise testing after 24 hours. RESULTS: HRR was increased from 25 +/- 10 beats/min at the first exercise testing to 30 +/- 13 beats/min at the second exercise testing (P < 0.001). Thereafter, participants were divided into two groups: Group I comprised 88 patients who presented augmentation of the HRR in the first compared to the second exercise testing, while group II comprised 40 patients who presented unchanged or reduced HRR. The rate-pressure product (RPP) at 1 mm ST-segment depression (ischemic threshold) at the second compared to the first exercise testing were significantly improved in group I patients (2345 +/- 3429 mmHg/min), while it was worsened in group II patients (-630 +/- 2510 mmHg/min) (P < 0.001). CONCLUSIONS: In a model of sequential exercise testings, myocardial adaptation to exercise-induced ischemia was associated with favorable modification of HRR.

Jacquemin B, Antoniades C, Nyberg F, Plana E, Müller M, Greven S, Salomaa V, Sunyer J, Bellander T, Chalamandaris AG et al. 2008. Common genetic polymorphisms and haplotypes of fibrinogen alpha, beta, and gamma chains affect fibrinogen levels and the response to proinflammatory stimulation in myocardial infarction survivors: the AIRGENE study. J Am Coll Cardiol, 52 (11), pp. 941-952. | Show Abstract | Read more

OBJECTIVES: This study was designed to investigate whether single nucleotide polymorphisms (SNPs) and haplotypes of the fibrinogen gene-cluster (fibrinogen chains alpha [FGA], beta [FGB], and gamma [FGG]) could explain the inter- and intraindividual variability of fibrinogen levels in patients with atherosclerosis. We also searched for genetic determinants affecting the responses of fibrinogen genes to proinflammatory stimulation. BACKGROUND: The mechanisms regulating fibrinogen levels are not fully understood, and they are likely to be regulated by complex gene-environment interactions. METHODS: In the AIRGENE study, 895 survivors of myocardial infarction from 5 European cities were followed prospectively for 6 to 8 months, and plasma fibrinogen, interleukin (IL)-6, and C-reactive protein levels were determined monthly. We analyzed 21 SNPs and the corresponding haplotypes in the 3 fibrinogen genes. RESULTS: Eight SNPs in FGA and FGB were significantly associated with fibrinogen levels. Similarly, 2 different haplotypes in FGA and 3 in FGB were also associated with mean fibrinogen levels. The IL-6 levels had a significant impact on the associations between SNPs/haplotypes in FGA/FGB and fibrinogen levels. We also identified SNPs and haplotypes in FGA and FGB with strong impact on the intraindividual variability of fibrinogen during the follow-up period. CONCLUSIONS: We identified common SNPs and haplotypes on FGA/FGB genes, explaining the interindividual and intraindividual variability of fibrinogen levels, in patients with a history of myocardial infarction. We have also identified for the first time, SNPs/haplotypes on FGA/FGB whose effects on fibrinogen expression are modified by the underlying IL-6 levels. These findings may have an impact on risk stratification and the design of genetically guided therapeutic approaches in patients with advanced atherosclerosis.

Doehring A, Antoniades C, Channon KM, Tegeder I, Lötsch J. 2008. Clinical genetics of functionally mild non-coding GTP cyclohydrolase 1 (GCH1) polymorphisms modulating pain and cardiovascular risk. Mutat Res, 659 (3), pp. 195-201. | Show Abstract | Read more

Guanosine triphosphate cyclohydrolase 1 (GCH1) is the first enzyme in the tetrahydrobiopterin (BH4) biosynthesis, an important co-factor for the formation of nitric oxide, biogenic amines and serotonin. Hereditary diseases such as DOPA-responsive dystonia and atypical phenylketonuria are known to be caused by coding or splice-site mutations in the GCH1 gene, leading mostly to a dominant negative enzyme. However, recent evidence suggests a clinical genetics of GCH1 beyond these hereditary loss-of-function diseases. That is, a non-coding GCH1 haplotype has been associated with reduced pain hypersensitivity and with altered vascular endothelial function. Moreover, the presence of the non-coding c.*243C>T variant in the 3'-untranslated region (3'-UTR) of the GCH1 gene has been associated with mildly increased heart rate and blood pressure. Here, we show that carriers of the pain-protective GCH1 haplotype also carry the c.*243C>T variant and vice versa. We thus demonstrate that apart from the coding or splice-site variants causing DOPA-responsive dystonia and atypical phenylketonuria, there is a common clinically relevant GCH1 genetics that is so far known to be related to unfavorable changes of endothelial function and a reduced risk for chronic pain.

Antoniades C, Tousoulis D, Stefanadis C. 2008. Smoking in Asians: it doesn't stop at vascular endothelium. Int J Cardiol, 128 (2), pp. 151-153. | Show Abstract | Read more

Smoking is a global risk factor for atherosclerosis, affecting societies all over the world. Smoking exerts its pro-atherogenic effects by triggering the generation of free radicals and by modifying vascular redox signaling. These abnormal vascular responses to cigarette smoking result into impaired endothelial function, decreased nitric oxide bioavailability, increased intima media thickness and finally atherosclerotic plaque formation in human arteries. Importantly, evidence suggests that cigarette smoking may have an effect on vascular smooth muscle cells function, leading to impaired endothelium-independent dilation in response to nitrate, in the brachial artery of healthy smokers. Taken together, it is now well established that smoking induces functional and structural abnormalities in the vascular wall, by mechanisms involving endothelial dysfunction and impairment of vascular smooth muscle cells in human arterial tree.

Tousoulis D, Ntarladimas I, Antoniades C, Vasiliadou C, Tentolouris C, Papageorgiou N, Latsios G, Stefanadis C. 2008. Acute effects of different alcoholic beverages on vascular endothelium, inflammatory markers and thrombosis fibrinolysis system. Clin Nutr, 27 (4), pp. 594-600. | Show Abstract | Read more

BACKGROUND & AIM: Mild alcohol consumption has been associated with decreased cardiovascular risk, although the underlying mechanisms are still unclear. We compared the acute effects of several alcoholic beverages on endothelial function, inflammatory process and thrombosis/fibrinolysis system in young adults. METHODS: In this randomized intervention trial, healthy young individuals with no risk factor for atherosclerosis were randomized into 5 equally sized groups and received an equal amount of alcohol (30 g), as red wine (264 ml), white wine (264 ml), beer (633 ml), whisky (79 ml) or water (250 ml). Forearm blood flow was determined by gauge-strain plethysmography, at baseline, 1 and 4 h after alcohol intake. Levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), C-reactive protein (CRP), fibrinogen (Fib), plasminogen activator inhibitor (PAI-1), von Willebrand factor (vWF) and tissue plasminogen activator (tPA) were determined at baseline and 4 h after alcohol consumption. RESULTS: Reactive hyperemia was significantly increased 1 h after beer and red wine consumption (p<0.05 for both), while it returned at baseline at 4 h (p=ns vs baseline) but remained unchanged in all the other groups. vWF was decreased in the beer and red wine groups (p<0.05 for both) only. PAI-1/tPA ratio remained unchanged only in red wine and control group. Inflammatory markers remained unchanged in all the groups. CONCLUSIONS: Acute consumption of red wine or beer improves endothelial function and decreases vWF levels, suggesting that the type of beverage may differently affect endothelial function and thrombosis/fibrinolysis system in healthy adults.

Tousoulis D, Antoniades C, Drolias A, Stefanadi E, Marinou K, Vasiliadou C, Tsioufis C, Toutouzas K, Latsios G, Stefanadis C. 2008. Selective serotonin reuptake inhibitors modify the effect of beta-blockers on long-term survival of patients with end-stage heart failure and major depression. J Card Fail, 14 (6), pp. 456-464. | Show Abstract | Read more

BACKGROUND: Major depression (MD) is a key feature in heart failure (HF), and it is unclear whether common antidepressive medications interact with cardiovascular drugs used for the treatment of patients with MD and HF, affecting their efficacy. We examined the impact of MD on long-term survival of patients with end-stage severe HF. We also evaluated the interaction between antidepressive medication and beta-blockers on the clinical outcome of these patients. METHODS AND RESULTS: The study population consisted of 250 patients with end-stage severe HF. Sixty-one percent of these patients suffered MD and were receiving selective serotonin reuptake inhibitors (SSRIs), serotonin norepinephrine reuptake inhibitors (SNRIs), or tricyclic antidepressants (TCA). All patients were followed prospectively for 18 months. The primary end point was cardiovascular death. At baseline, patients with severe MD had higher serum interleukin 6 (P < .05) and soluble vascular cell adhesion molecule (P < .01). During the follow-up, 167 cardiovascular deaths were reported, and MD was 1 of the major predictors of cardiovascular death (P = .031), whereas treatment with angiotensin receptor inhibitors and statins were also important negative predictors of mortality (P = .036 and P = .039, respectively). Although beta-blockers had a borderline nonsignificant effect on cardiovascular mortality in the overall population, they had a striking beneficial effect among those patients with major depression receiving SSRIs (P = .006), whereas they had a negative effect on mortality in those patients receiving SNRIs/TCAs (P = .025). CONCLUSIONS: MD is an independent predictor of cardiovascular death in patients with end-stage HF. beta-blockers are associated with lower cardiovascular mortality in patients with end-stage HF and depression only when they are combined with SSRIs.

Antoniades C, Shirodaria C, Van Assche T, Cunnington C, Tegeder I, Lötsch J, Guzik TJ, Leeson P, Diesch J, Tousoulis D et al. 2008. GCH1 haplotype determines vascular and plasma biopterin availability in coronary artery disease effects on vascular superoxide production and endothelial function. J Am Coll Cardiol, 52 (2), pp. 158-165. | Show Abstract | Read more

OBJECTIVES: This study sought to determine the effects of endogenous tetrahydrobiopterin (BH4) bioavailability on endothelial nitric oxide synthase (eNOS) coupling, nitric oxide (NO) bioavailability, and vascular superoxide production in patients with coronary artery disease (CAD). BACKGROUND: GTP-cyclohydrolase I, encoded by the GCH1 gene, is the rate-limiting enzyme in the biosynthesis of BH4, an eNOS cofactor important for maintaining enzymatic coupling. We examined the associations between haplotypes of the GCH1 gene, GCH1 expression and biopterin levels, and the effects on endothelial function and vascular superoxide production. METHODS: Blood samples and segments of internal mammary arteries and saphenous veins were obtained from patients with CAD undergoing coronary artery bypass grafting (n = 347). The GCH1 haplotypes were defined by 3 polymorphisms: rs8007267G<A, rs3783641A<T, and rs10483639C<G (X haplotype: A, T, G; O haplotype: any other combination). Vascular superoxide (+/- the eNOS inhibitor N(G)-nitro-L-arginine methyl ester [L-NAME]) was measured by lucigenin-enhanced chemiluminescence, whereas the vasorelaxations of saphenous veins to acetylcholine were evaluated ex vivo. RESULTS: Haplotype frequencies were OO 70.6%, XO 27.4%, and XX 2.0%. The X haplotype was associated with significantly lower vascular GCH1 messenger ribonucleic acid expression and substantial reductions in both plasma and vascular BH4 levels. In X haplotype carriers both vascular superoxide and L-NAME-inhibitable superoxide were significantly increased, and were associated with reduced vasorelaxations to acetylcholine. CONCLUSIONS: GCH1 gene expression, modulated by a particular GCH1 haplotype, is a major determinant of BH4 bioavailability both in plasma and in the vascular wall in patients with CAD. Genetic variation in GCH1 underlies important differences in endogenous BH4 availability and is a determinant of eNOS coupling, vascular redox state, and endothelial function in human vascular disease.

Koumallos N, Paschalis A, Antoniades C, Tousoulis D, Simpsiris P, Tolios I, Stefanadis C, Leonidas D. 2008. Valve replacement for Brucella endocarditis: two case reports. Int J Cardiol, 127 (2), pp. e83-e85. | Show Abstract | Read more

We report two cases of successful treatment of Brucella endocarditis. Both of them were treated with antibiotics and aortic valve replacement after Brucellosis was diagnosed. In one of these cases emergency operation was required. Our observations suggest that a combined surgical and medical treatment is the best option for the management of this disease. B. endocarditis should be operated after improvement of clinical status but emergency cardiac surgery may be required if heart failure develops.

Siasos G, Tousoulis D, Vlachopoulos C, Antoniades C, Stefanadi E, Ioakeimidis N, Andreou I, Zisimos K, Papavassiliou AG, Stefanadis C. 2008. Short-term treatment with L-arginine prevents the smoking-induced impairment of endothelial function and vascular elastic properties in young individuals. Int J Cardiol, 126 (3), pp. 394-399. | Show Abstract | Read more

BACKGROUND: L-arginine, the substrate for endothelial nitric oxide synthase, is essential for normal endothelial function. Aim of the present study was to investigate in healthy smokers the effect of a short-term daily L-arginine administration on vascular function. METHODS: We studied the effect of a 3-day oral administration of L-arginine in 10 healthy smokers (24.3+/-0.73 years old) on 3 occasions (day , day 1 and day 3). The study was carried out on two separate arms, one with L-arginine (7 gr/d) and one with placebo according to a randomized, placebo-controlled, double-blind, cross-over design. Measurements were carried out before, immediately after (Sm0) and 20 min after (Sm20) cigarette smoking. Endothelial function was evaluated by flow-mediated dilatation (FMD) of the brachial artery. Carotid-femoral pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) as a measure of arterial wave reflections. RESULTS: Compared to placebo, L-arginine led to an increase of FMD (p<0.05 at day 2), indicating a favorable effect on endothelial function, which however lost significance at day 3. l-arginine induced a progressive decrease of PWV and AIx at both day 2 and day 3 (p<0.01 vs baseline for all). L-arginine blunted the acute smoking-induced increase of AIx at both day 1 (p<0.05) and day 3 (p<0.01), and there was a trend to protect the smoking-induced change of PWV at day 3 (p<0.1). CONCLUSIONS: Short-term daily administration of L-arginine improves arterial performance in healthy smokers and abrogates the smoking-induced increase in arterial stiffness and wave reflections in these individuals.

Tousoulis D, Antoniades C, Marinou K, Vasiliadou C, Bouras G, Stefanadi E, Latsios G, Siasos G, Toutouzas K, Stefanadis C. 2008. Methionine-loading rapidly impairs endothelial function, by mechanisms independent of endothelin-1: evidence for an association of fasting total homocysteine with plasma endothelin-1 levels. J Am Coll Nutr, 27 (3), pp. 379-386. | Show Abstract | Read more

OBJECTIVE: Homocysteinemia is associated with elevated oxidative stress and impaired endothelial function. In the present study we examined the impact of oxidative stress in the development of endothelial dysfunction in both chronic and acute (methionine-induced) homocysteinemia in humans. We also examined the role of endothelin-1 (ET-1) in the development of endothelial dysfunction in these two conditions. METHODS: In this double-blind placebo controlled study, 28 subjects of both genders (14 with homocysteinemia and 14 healthy controls) underwent methionine-loading (100mg/Kg body weight) in a standard juice, containing vitamins C (2g) plus E (800IU) (n = 14) or no vitamins (placebo group, n = 14). Forearm vasodilatory response to reactive hyperemia, plasma total homocysteine (tHcy), oxidized LDL (ox-LDL), ET-1 and soluble vascular cell adhesion molecule (sVCAM-1), were evaluated at baseline and 4 hours post methionine loading (4hPML). RESULTS: Chronic homocysteinemia was associated with increased oxLDL (p < 0.01), higher ET-1 (p < 0.05) and impaired endothelial function (p < 0.01). However, oxLDL (but not ET-1) was increased 4hPML in the placebo group, an effect prevented by antioxidant vitamins. The development of severe endothelial dysfunction 4hPML was not however prevented by antioxidants. In linear regression analysis, fasting tHcy was an independent predictor of baseline oxLDL (p = 0.0001), but not of ET-1 levels. On the contrary, oxLDL was the main predictor of ET-1 (p = 0.008), suggesting that tHcy may increase ET-1 by enhancing the production of oxLDL. CONCLUSIONS: Both chronic and acute methionine-induced homocysteinemia are associated with elevated oxidative stress status. Although ET-1 is increased in chronic homocysteinemia, it does not participate in the rapid development of endothelial dysfunction after methionine loading. These findings suggest that despite its potential role in chronic homocysteinemia, ET-1 has a limited contribution to the development of endothelial dysfunction in acute, methionine-induced homocysteinemia in humans.

Tousoulis D, Briasoulis A, Antoniades C, Stefanadi E, Stefanadis C. 2008. Heart regeneration: what cells to use and how? Curr Opin Pharmacol, 8 (2), pp. 211-218. | Show Abstract | Read more

Coronary artery disease (CAD) is the leading cause of death in modern societies. Recent achievements in the treatment of CAD including statins, ACE inhibitors, beta blockers, and interventional procedure improved the outcome of patients with CAD, but this conventional approach failed to control cardiovascular mortality. Nowadays, cells (stem cells) and their potential role in managing patients with heart disease is a field of intensive research. Various types of cells have been used for transplantation targeting heart regeneration, including bone marrow cells (BMCs), cardiac stem cells (CSCs), endothelial progenitor cells (EPCs), skeletal myoblasts (SMs), adipose stroma tissue cells (ATSCs), mesenchymal cells (MCs), and embryonic stem cells (ESCs). Several routes have been used to deliver these cells to human myocardium or to the coronary circulation such as, intracoronary injection, intravenous infusion, direct injection into the ventricular wall, or transepicardial/transendocardial infusions. Although the results of the recent clinical trials in this area are rather conflicting, these therapeutic approaches seem to be promising for the treatment of ischemic heart disease.

Tousoulis D, Kourtellaris P, Antoniades C, Vasiliadou C, Papageorgiou N, Tentolouris C, Siasos G, Stefanadi E, Stefanadis C. 2008. Effects of irbesartan and perindopril on forearm reactive hyperemia and inflammatory process, in normotensive patients with coronary artery disease. Int J Cardiol, 124 (1), pp. 127-129. | Read more

Brili S, Tousoulis D, Antoniades C, Vasiliadou C, Karali M, Papageorgiou N, Ioakeimidis N, Marinou K, Stefanadi E, Stefanadis C. 2008. Effects of ramipril on endothelial function and the expression of proinflammatory cytokines and adhesion molecules in young normotensive subjects with successfully repaired coarctation of aorta: a randomized cross-over study. J Am Coll Cardiol, 51 (7), pp. 742-749. | Show Abstract | Read more

OBJECTIVES: The purpose of this study was to evaluate the effect of ramipril on endothelial function and inflammatory process in a group of normotensive subjects with successfully repaired coarctation of the aorta (SCR). BACKGROUND: Subjects with SCR experience higher long-term cardiovascular risk as a result of the relapse of arterial hypertension or owing to nonreversible structural changes in the pre-coarctation arterial tree. These subjects experience endothelial dysfunction in the right forearm and appear to have elevated levels of proatherogenic inflammatory markers, even in the absence of arterial hypertension. METHODS: Twenty young individuals age 27.3 +/- 2.4 years old with SCR 13.9 +/- 2.2 years previously, received ramipril 5 mg/day for 4 weeks in a randomized, cross-over, controlled trial. Endothelial function was evaluated in the right forearm by gauge-strain plethysmography, and serum levels of interleukin (IL)-1b, IL-6, soluble CD40 ligand (sCD40L), and soluble vascular cell adhesion molecule (sVCAM)-1 were determined by enzyme-linked immunosorbent assay. RESULTS: Ramipril improved endothelial function (p < 0.001) and decreased the expression of proinflammatory cytokine IL-6 (p < 0.05) and sCD40L (p < 0.01). Furthermore, ramipril decreased serum levels of sVCAM-1 (p < 0.01) but failed to affect serum levels of C-reactive protein. These effects were independent of blood pressure lowering. CONCLUSIONS: Ramipril reversed the impaired endothelial function and decreased the expression of proinflammatory cytokine IL-6, sCD40L, and adhesion molecules in normotensive subjects with SCR. These findings imply that ramipril treatment may have antiatherogenic effects in subjects with SCR, even in the absence of arterial hypertension.

Tousoulis D, Antoniades C, Stefanadis C. 2008. Statins ameliorate atherosclerosis induced by inhibition of nitric oxide synthase: another novel vascular protective mechanism? Int J Cardiol, 123 (2), pp. 91-93. | Show Abstract | Read more

Endothelial nitric oxide synthase (eNOS), the main source of endothelium-derived nitric oxide (NO), appears to be a rational therapeutic target in atherosclerosis. The exact mechanisms regulating eNOS protein expression in human vasculature are still under intensive investigation. Recent evidence suggests that statin treatment induces the expression of eNOS in vascular endothelium, leading to a respective improvement of endothelial function. Among other mechanisms, it seems that statins increase eNOS protein levels in the vasculature, partly by up-regulating klotho protein expression. This novel observation is consistent with several lines of clinical evidence suggesting that statins have antiatherogenic effects in human vasculature, by mechanisms other than lipid-lowering.

Tousoulis D, Kampoli AM, Stefanadi E, Antoniades C, Siasos G, Papavassiliou AG, Stefanadis C. 2008. New biochemical markers in acute coronary syndromes. Curr Med Chem, 15 (13), pp. 1288-1296. | Show Abstract | Read more

This article comments on the role of the most important biochemical markers that are already applied in clinical practice or are still under research, in Acute Coronary Syndromes (ACS). Cardiac troponin (cTn) is established as the 'gold standard' in the diagnosis of ACS. C-reactive protein (CRP) and especially high-sensitivity CRP (hs-CRP) are considered to be the most useful inflammatory markers for clinical practice in the setting of acute coronary syndrome. Brain-type natriuretic peptide (BNP) and the amino terminal fragment of the prohormone BNP (NT-proBNP) appear to provide prognostic information in individuals admitted for acute coronary syndromes. Microalbuminuria in nondiabetics appears to be a signal from the kidney that the vasculature, particularly the endothelium, is not functioning properly. Increased plasma levels of cystatin C, neopterin, myeloperoxidase, and pregnancy associated protein are associated with adverse cardiovascular outcomes, cardiovascular and noncardiovascular death, and possibly cerebrovascular disease. Furthermore, recent evidence suggests that serum levels of CD40-CD40L pathway exert important roles in progression, and outcome of acute coronary syndrome. In the future further, studies are necessary to elucidate the exact role of the new biochemical markers in ACS.

Antoniades C, Shirodaria C, Crabtree M, Rinze R, Alp N, Cunnington C, Diesch J, Tousoulis D, Stefanadis C, Leeson P et al. 2007. Altered plasma versus vascular biopterins in human atherosclerosis reveal relationships between endothelial nitric oxide synthase coupling, endothelial function, and inflammation. Circulation, 116 (24), pp. 2851-2859. | Show Abstract | Read more

BACKGROUND: Tetrahydrobiopterin (BH4) is a key regulator of endothelial nitric oxide synthase (eNOS) activity and coupling. However, the extent to which vascular and/or systemic BH4 levels are altered in human atherosclerosis and the importance of BH4 bioavailability in determining endothelial function and oxidative stress remain unclear. We sought to define the relationships between plasma and vascular biopterin levels in patients with coronary artery disease and to determine how BH4 levels affect endothelial function, eNOS coupling, and vascular superoxide production. METHODS AND RESULTS: Samples of saphenous veins and internal mammary arteries were collected from 219 patients with coronary artery disease undergoing coronary artery bypass grafting. We determined plasma and vascular levels of biopterins, vasomotor responses to acetylcholine, and vascular superoxide production in the presence and absence of the eNOS inhibitor N(G)-nitro-L-arginine methyl ester. High vascular BH4 was associated with greater vasorelaxations to acetylcholine (P<0.05), whereas high plasma BH4 was associated with lower vasorelaxations in response to acetylcholine (P<0.05). Furthermore, an inverse association was observed between plasma and vascular biopterins (P<0.05 for both saphenous veins and internal mammary arteries). High vascular (but not plasma) BH4 was associated with reduced total and N(G)-nitro-L-arginine methyl ester-inhibitable superoxide, suggesting improved eNOS coupling. Finally, plasma but not vascular biopterin levels were correlated with plasma C-reactive protein levels (P<0.001). CONCLUSIONS: An inverse association exists between plasma and vascular biopterins in patients with coronary artery disease. Vascular but not plasma BH4 is an important determinant of eNOS coupling, endothelium-dependent vasodilation, and superoxide production in human vessels, whereas plasma biopterins are a marker of systemic inflammation.

Skoumas I, Masoura C, Pitsavos C, Tousoulis D, Papadimitriou L, Aznaouridis K, Chrysohoou C, Giotsas N, Toutouza M, Tentolouris C et al. 2007. Evidence that non-lipid cardiovascular risk factors are associated with high prevalence of coronary artery disease in patients with heterozygous familial hypercholesterolemia or familial combined hyperlipidemia. Int J Cardiol, 121 (2), pp. 178-183. | Show Abstract | Read more

BACKGROUND: Heterozygous familial hypercholesterolemia (hFH) and familial combined hyperlipidemia (FCH) have been associated with increased risk for coronary artery disease (CAD), but the impact of traditional risk factors to the incidence of CAD in these patients remains unknown. The present study evaluates the contribution of such risk factors to the development of CAD in these two dyslipidemic populations. METHODS: This cross-sectional study enrolled a total 1306 subjects; 600 individuals with hFH (mean age 41+/-13 years, 261 males and 339 females), and 706 individuals with FCH (mean age 49+/-11 years, 463 males and 243 females). Blood samples were collected after 12 hours fasting period, and serum lipids were determined. Multivariate logistic regression models were used to estimate the odds ratios of CAD based on the type of hyperlipidemia, after adjustment for demographic characteristics and risk factors. RESULTS: Subjects with FCH were older (P<0.001), and they had a significantly increased prevalence of hypertension, diabetes and metabolic syndrome (40 vs. 10%, 13 vs. 2% and 41 vs. 6% respectively, all P<0.001) compared to the hFH group. Total cholesterol, LDL-cholesterol, and apolipoprotein B levels were higher (all P<0.001) in hFH subjects. Although in multivariate analysis lipid abnormalities found in hFH were associated with increased risk of CAD (P<0.001) compared with lipid abnormalities of FCH, the overall prevalence of CAD was similar between the two groups (16.7 vs. 15.3%, P=NS). CONCLUSIONS: Despite the high atherogenic potential of altered lipid metabolism found in hFH, the prevalence of CAD is similarly increased in patients with hFH or FCH. This may be related to the clustering of non-lipid cardiovascular risk factors, such as diabetes mellitus, observed in patients with FCH.

Choudhary BP, Antoniades C, Brading AF, Galione A, Channon K, Taggart DP. 2007. Diabetes mellitus as a predictor for radial artery vasoreactivity in patients undergoing coronary artery bypass grafting. J Am Coll Cardiol, 50 (11), pp. 1047-1053. | Show Abstract | Read more

OBJECTIVES: Our purpose was to examine the impact of diabetes mellitus (DM) on vasoreactivity and endothelial function of radial artery (RA) grafts ex vivo. BACKGROUND: The arteriopathy associated with DM may influence the surgeon's choice of conduits for revascularization. Arterial conduits and especially the RA are prone to vasospasm in the perioperative period. METHODS: The study population consisted of 98 patients with coronary artery disease undergoing coronary artery bypass grafting by using RA grafts. The maximum contractions of RA segments induced by K+ (66 mmol/l) and clinically important vasoconstrictors such as adrenaline (5 x 10(-5) mol/l), angiotensin II (10(-6) mol/l), and prostaglandin F2alpha (PGF2alpha) (10(-6) mol/l) were recorded. Relaxation of RA rings to carbachol (10(-4) mol/l) was used as a measure of endothelial function. Multivariate analysis was then applied to determine the role of clinical characteristics on the vasomotor responses to these agents. RESULTS: Vessels from patients with DM had greater contractions in response to adrenaline (p < 0.05), angiotensin (p < 0.05), and PGF2alpha (p < 0.01) compared with non-DM vessels, despite the similar vasoconstrictions induced by high K+ (p = NS). Diabetes mellitus was also associated with smaller vasorelaxations in response to carbachol (p < 0.001). In multivariate analysis, DM was an independent predictor of RA contractions in response to adrenaline (beta [SE] 3.085 [1.410], p = 0.031), angiotensin II (beta [SE] 3.838 [1.552], p = 0.015), and PGF2alpha (beta [SE] 4.609 [1.908], p = 0.018) but not K+ (p = NS). Diabetes mellitus was also independently associated with the vasorelaxations in response to carbachol (beta [SE] -15.645 [2.622], p = 0.0001). CONCLUSIONS: Diabetes mellitus is associated with impaired endothelial function and greater contractions of RA grafts in response to all of the clinically relevant vasoconstrictors. These findings suggest that the RA of diabetic patients may be more prone to spasm in response to endogenous vasoconstrictors, an observation with important implications for surgeons' choice of conduits in this cohort of patients.

Vyssoulis GP, Tousoulis D, Antoniades C, Dimitrakopoulos S, Zervoudaki A, Stefanadis C. 2007. Alpha-1 microglobulin as a new inflammatory marker in newly diagnosed hypertensive patients. Am J Hypertens, 20 (9), pp. 1016-1021. | Show Abstract | Read more

BACKGROUND: The alpha-1 microglobulin (A1M) is considered to be a marker of renal insufficiency, suggesting disturbed tubular function. In the present study we examined the ability of urinary A1M excretion to reflect the overall inflammatory status in patients with newly diagnosed essential hypertension and normal renal function. METHODS: The study population consisted of 1445 nondiabetic patients with newly diagnosed arterial hypertension and no evidence of renal insufficiency. Serum levels of C-reactive protein (CRP), serum amyloid alpha (SAA), and plasma fibrinogen, as well as urinary A1M excretion, were estimated. Multivariate analysis was performed to evaluate the associations between hypertension; A1M urinary excretion; and circulating levels of CRP, SAA, and fibrinogen. RESULTS: Patients with systolic hypertension had higher CRP, SAA, fibrinogen, and A1M compared with patients with isolated diastolic hypertension (P < .0001 for all). In multivariate analysis, systolic (but not diastolic) blood pressure (BP) was independently associated with A1M, CRP, and SAA (P < .0001 for all), whereas urinary A1M was also independently correlated with inflammatory markers such as CRP (P = .0001) and SAA (P = .0001). CONCLUSIONS: Urinary A1M is independently associated with circulating acute phase proteins in patients with newly diagnosed hypertension, whereas it is closely associated with systolic but not diastolic BP. Our findings suggest that urinary alpha-1 microglobulin may reflect the overall inflammatory status in patients with newly diagnosed essential hypertension, beyond its value as a marker of renal function.

Antoniades C, Shirodaria C, Stefanadis C, Channon KM. 2007. Homocysteine lowering: any use in atherosclerosis? Hellenic J Cardiol, 48 (5), pp. 249-251.

Tousoulis D, Antoniades C, Stefanadis C. 2007. Assessing inflammatory status in cardiovascular disease. Heart, 93 (8), pp. 1001-1007. | Read more

Tousoulis D, Antoniades C, Nikolopoulou A, Koniari K, Vasiliadou C, Marinou K, Koumallos N, Papageorgiou N, Stefanadi E, Siasos G, Stefanadis C. 2007. Interaction between cytokines and sCD40L in patients with stable and unstable coronary syndromes. Eur J Clin Invest, 37 (8), pp. 623-628. | Show Abstract | Read more

BACKGROUND: Evidence suggests that soluble CD40-ligand (sCD40L) is elevated in coronary artery disease (CAD) and is released from activated platelets during the acute myocardial infarction (AMI). Although sCD40L is part of immune response, the mechanisms regulating its release in different disease states remain unknown. MATERIALS AND METHODS: This study enrolled 596 subjects: 201 patients with stable CAD, 109 patients with AMI and 286 healthy controls. Circulating levels of sCD40L, interleukin-6 (IL-6), soluble vascular cell adhesion molecule-a (sVCAM-1) and soluble intercellular adhesion molecule-1 (sICAM-1) were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS: Patients with AMI (n = 109) had higher levels of sCD40L and IL-6 compared to both CAD (n = 201) (P < 0.01) and controls (n = 286) (P < 0.01), while CAD also had higher levels of sCD40L and IL-6 compared to controls (P < 0.01). Similarly, sICAM-1 and sVCAM-1 levels were higher in CAD and AMI compared to controls (P < 0.05). IL-6 was the only parameter independently associated with sCD40L in healthy individuals [beta (SE):0.491(0.096), P = 0.0001]. However, in CAD or AMI, only diabetes mellitus [beta (SE): 2.689 (1.082), P = 0.044 and beta (SE): 10.406 (3.215), P = 0.002, respectively] and smoking [beta (SE): 3.470 (1.111), P = 0.002 and beta (SE): 9.694 (2.478), P = 0.0001, respectively] (but not IL-6), were independently associated with sCD40L levels. CONCLUSIONS: Both CAD and AMI are accompanied by increased levels of sCD40L in parallel with an elevation of proinflammatory cytokine IL-6 and adhesion molecules sVCAM-1 and sICAM-1. Diabetes mellitus and smoking (but not IL-6 or adhesion molecules) were the only factors independently associated with sCD40L levels in CAD and AMI patients.

Rückerl R, Greven S, Ljungman P, Aalto P, Antoniades C, Bellander T, Berglind N, Chrysohoou C, Forastiere F, Jacquemin B et al. 2007. Air pollution and inflammation (interleukin-6, C-reactive protein, fibrinogen) in myocardial infarction survivors. Environ Health Perspect, 115 (7), pp. 1072-1080. | Show Abstract | Read more

BACKGROUND: Numerous studies have found that ambient air pollution has been associated with cardiovascular disease exacerbation. OBJECTIVES: Given previous findings, we hypothesized that particulate air pollution might induce systemic inflammation in myocardial infarction (MI) survivors, contributing to an increased vulnerability to elevated concentrations of ambient particles. METHODS: A prospective longitudinal study of 1,003 MI survivors was performed in six European cities between May 2003 and July 2004. We compared repeated measurements of interleukin 6 (IL-6), fibrinogen, and C-reactive protein (CRP) with concurrent levels of air pollution. We collected hourly data on particle number concentrations (PNC), mass concentrations of particulate matter (PM) < 10 microm (PM(10)) and < 2.5 microm (PM(2.5)), gaseous pollutants, and meteorologic data at central monitoring sites in each city. City-specific confounder models were built for each blood marker separately, adjusting for meteorology and time-varying and time-invariant covariates. Data were analyzed with mixed-effects models. RESULTS: Pooled results show an increase in IL-6 when concentrations of PNC were elevated 12-17 hr before blood withdrawal [percent change of geometric mean, 2.7; 95% confidence interval (CI), 1.0-4.6]. Five day cumulative exposure to PM(10) was associated with increased fibrinogen concentrations (percent change of arithmetic mean, 0.6; 95% CI, 0.1-1.1). Results remained stable for smokers, diabetics, and patients with heart failure. No consistent associations were found for CRP. CONCLUSIONS: Results indicate an immediate response to PNC on the IL-6 level, possibly leading to the production of acute-phase proteins, as seen in increased fibrinogen levels. This might provide a link between air pollution and adverse cardiac events.

Antoniades C, Tousoulis D, Marinou K, Papageorgiou N, Bosinakou E, Tsioufis C, Stefanadi E, Latsios G, Tentolouris C, Siasos G, Stefanadis C. 2007. Effects of insulin dependence on inflammatory process, thrombotic mechanisms and endothelial function, in patients with type 2 diabetes mellitus and coronary atherosclerosis. Clin Cardiol, 30 (6), pp. 295-300. | Show Abstract | Read more

BACKGROUND: Type 2 diabetes mellitus (T2DM) is characterized by endothelial dysfunction, increased thrombogenicity and abnormal inflammatory response. HYPOTHESIS: We hypothesizsed that insulin dependence/exogenous insulin administration may affect thrombotic/inflammatory status and endothelial function in patients with T2DM and coronary artery disease (CAD). METHODS: Fifty-five patients with T2DM + CAD (26 insulin-treated (INS) and 29 under oral biguanide + sulphonylurea (TABL)) were recruited. Endothelial function was assessed by gauge-strain plethysmography, and serum levels of inflammatory and thrombotic markers were determined by enzyme linked immunosorbent assay. RESULTS: There was no significant difference in endothelium-dependent dilation (EDD) between the study groups, while EDD was correlated with fasting glucose levels in both INS (r = - 0.776, p = 0.0001) and TABL (r = - 0.702, p = 0.0001). Patients in INS group had higher levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), monocyte chemoattractant protein (MCP-1) and vascular cell adhesion molecule (sVCAM-1), compared to TABL. However, TNF-alpha was negatively correlated with protein C (PrtC) only in INS (r = - 0.726, p = 0.01) but not in TABL group (r = - 0.066, p = 0.738). Similarly, sVCAM-1 was correlated with PrtC only among INS patients (r = - 0.451, p = 0.046) but not in TABL (r = 0.069, p = 0.727). In multivariate analysis, insulin dependence was a predictor of IL-6, TNF-alpha, MCP-1 and sVCAM-1 levels independently from the patients' demographic characteristics, the angiographic extend of CAD or the duration of diabetes. CONCLUSIONS: Insulin treatment in patients with type 2 diabetes mellitus affects the expression of inflammatory cytokines and subsequently modifies the thrombotic mechanisms in patients with coronary atherosclerosis, independently from the duration of diabetes and the extend of coronary artery disease.

Antoniades C, Tousoulis D, Stefanadis C. 2007. Nitric oxide-releasing aspirin: will it say NO to atherothrombosis? Int J Cardiol, 118 (2), pp. 170-172. | Show Abstract | Read more

Aspirin is a powerful anti-platelet drug widely used in patients with coronary atherosclerosis, but its side effects and especially its toxicity for gastrointestinal tract limit its usefulness in specific groups of patients. A new category of agents, nitric oxide-releasing aspirins (such as NCX-4016), seems to provide an alternative solution. Although this drug is still at phase II clinical trials, it has provided promising results until now. When administered in vivo, it is separated into an aspirin moiety and an NO-donating complex, providing both the antithrombotic effect of aspirin and the gastroprotective effect of NO. Additionally, it increases NO bioavailability as a vascular level, and it may have the antiatherogenic properties of endogenously produced NO. Finally, recent evidence suggests that it may also improve functional aspects of vein grafts used in CABG, with possible benefit on graft patency. However, the outcome of the large ongoing trials is needed before any conclusion is made about the role of NO-releasing aspirins in cardiovascular disease.

Shirodaria C, Antoniades C, Lee J, Jackson CE, Robson MD, Francis JM, Moat SJ, Ratnatunga C, Pillai R, Refsum H et al. 2007. Global improvement of vascular function and redox state with low-dose folic acid: implications for folate therapy in patients with coronary artery disease. Circulation, 115 (17), pp. 2262-2270. | Show Abstract | Read more

BACKGROUND: Although dietary folate fortification lowers plasma homocysteine and may reduce cardiovascular risk, high-dose folic acid therapy appears to not alter clinical outcome. Folic acid and its principal circulating metabolite, 5-methyltetrahydrofolate, improve vascular function, but mechanisms relating folate dose to vascular function remain unclear. We compared the effects of folic acid on human vessels using pharmacological high-dose versus low-dose treatment, equivalent to dietary folate fortification. METHODS AND RESULTS: Fifty-six non-folate-fortified patients with coronary artery disease were randomized to receive low-dose (400 microg/d) or high-dose (5 mg/d) folic acid or placebo for 7 weeks before coronary artery bypass grafting. Vascular function was quantified by magnetic resonance imaging before and after treatment. Vascular superoxide and nitric oxide bioavailability were determined in segments of saphenous vein and internal mammary artery. Low-dose folic acid increased nitric oxide-mediated endothelium-dependent vasomotor responses, reduced vascular superoxide production, and improved enzymatic coupling of endothelial nitric oxide synthase through availability of the cofactor tetrahydrobiopterin. No further improvement in these parameters occurred with high-dose compared with low-dose treatment. Whereas plasma 5-methyltetrahydrofolate increased proportionately with treatment dose of folic acid, vascular tissue 5-methyltetrahydrofolate showed no further increment with high-dose compared with low-dose folic acid. CONCLUSIONS: Low-dose folic acid treatment, comparable to daily intake and dietary fortification, improves vascular function through effects on endothelial nitric oxide synthase and vascular oxidative stress. High-dose folic acid treatment provides no additional benefit. These direct vascular effects are related to vascular tissue levels of 5-methyltetrahydrofolate rather than plasma levels. High-dose folic acid treatment likely confers no further benefit in subjects already receiving folate supplementation.

Antoniades C, Tousoulis D, Koumallos N, Marinou K, Stefanadis C. 2007. Levosimendan: beyond its simple inotropic effect in heart failure. Pharmacol Ther, 114 (2), pp. 184-197. | Show Abstract | Read more

Classic inotropic agents provide short-term haemodynamic improvement in patients with heart failure, but their use has been associated with poor prognosis. A new category of inotropic agents, the Ca(2+) sensitizers, may provide an alternative longer lasting solution. Levosimendan is a relatively new Ca(2+) sensitizer which offers haemodynamic and symptomatic improvement by combining a positive inotropic action via Ca(2+) sensitization and a vasodilatory effect via adenosine triphosphate(ATP)-sensitive K(+) (K(ATP)), Ca(2+)-activated K(+) (K(Ca)(2+)) and voltage-dependent K(+) (K(V)) channels activation. Levosimendan also seems to induce a prolonged haemodynamic improvement in patients with heart failure as a result of the long half-life of its active metabolite, OR-1896. Furthermore, there is also evidence that levosimendan may have additional antiinflammatory and antiapoptotic properties, affecting important pathways in the pathophysiology of heart failure. Despite the initial reports for a clear benefit of levosimendan on short- and long-term mortality in patients with severe heart failure, the results from the recent clinical trials are rather disappointing, and it is still unclear whether it is superior to dobutamine in affecting survival of patients with severe heart failure. In conclusion, levosimendan is a promising agent for the treatment of decompensated heart failure. As further to its positive inotropic effect, it affects multiple pathways with key roles in the pathophysiology of heart failure. The results of the ongoing trials examining the effect of levosimendan on mortality in patients with heart failure will hopefully resolve the controversy as to whether levosimendan is superior to classic inotropic agents for the treatment of severe heart failure.

Tousoulis D, Böger RH, Antoniades C, Siasos G, Stefanadi E, Stefanadis C. 2007. Mechanisms of disease: L-arginine in coronary atherosclerosis--a clinical perspective. Nat Clin Pract Cardiovasc Med, 4 (5), pp. 274-283. | Show Abstract | Read more

L-arginine is the substrate of endothelial nitric oxide synthase and the main precursor of nitric oxide in the vascular endothelium, thus its effects are mediated largely by increases in nitric oxide production. L-arginine has antioxidant and antiapoptotic properties, increases smooth muscle relaxation, inhibits the expression of adhesion molecules and chemotactic peptides, decreases endothelin-1 expression, and inhibits platelet aggregation. This amino acid also improves endothelial function in patients with coronary artery disease and dilates human epicardial atheromatous coronary arteries. Despite the positive results from small case-control studies, it is still unclear whether chronic administration of L-arginine has any effect on clinical outcome in patients with coronary artery disease. In addition, other indirect strategies, such as the inhibition of arginase, could prove more effective at improving intracellular L-arginine bioavailability than exogenous L-arginine administration. The potential clinical usefulness of L-arginine, therefore, needs further evaluation in large, prospective clinical trials. Here, we present a critique of the existing literature about the role of L-arginine in the prevention of atherosclerosis.

Siasos G, Tousoulis D, Antoniades C, Stefanadi E, Stefanadis C. 2007. L-Arginine, the substrate for NO synthesis: an alternative treatment for premature atherosclerosis? Int J Cardiol, 116 (3), pp. 300-308. | Show Abstract | Read more

L-Arginine is the substrate of endothelial nitric oxide synthase (eNOS) and the main precursor of nitric oxide (NO) in the vascular endothelium. L-Arginine improves endothelial function in patients with hypercholesterolemia, hypertension and smokers, while its role in diabetes remains unclear. Oral supplementation of L-arginine leads to a significant improvement of endothelium-dependent forearm vasodilation in hypercholesterolemic patients, while intravenous infusion of L-arginine improves endothelial function in healthy smokers. L-Arginine has anti-hypertensive properties, although its effects on endothelial function in hypertensive patients needs further evaluation. In conclusion, L-arginine administration may be useful in patients with premature atherosclerosis.

Antoniades C, Tousoulis D, Stefanadis C. 2007. Effects of endothelial nitric oxide synthase gene polymorphisms on oxidative stress, inflammatory status, and coronary atherosclerosis: an example of a transient phenotype. J Am Coll Cardiol, 49 (11), pp. 1226. | Read more

Lee JM, Shirodaria C, Jackson CE, Robson MD, Antoniades C, Francis JM, Wiesmann F, Channon KM, Neubauer S, Choudhury RP. 2007. Multi-modal magnetic resonance imaging quantifies atherosclerosis and vascular dysfunction in patients with type 2 diabetes mellitus. Diab Vasc Dis Res, 4 (1), pp. 44-48. | Show Abstract | Read more

Vascular magnetic resonance imaging (MRI) is emerging as a powerful research tool. We studied 18 patients with type 2 diabetes mellitus and 20 controls (all with coronary artery disease). MRI measured distensibility, pulse wave velocity (PWV) and atherosclerosis in the aorta, and brachial artery flow-mediated dilatation (FMD). Patients with diabetes showed lower aortic distensibility (2.1 x 10(-3) vs . 3.5 x 10(-3) mmHg-1, p<0.01), faster PWV (8.8 vs ., 6.2 m/s, p<0.01) and impaired FMD (8.5% vs . 13.8%, p<0.05). Diabetes was an independent negative predictor of distensibility. Aortic atherosclerosis was similar in the two groups. There was a negative correlation between aortic distensibility and atherosclerosis in control subjects only, suggesting that other factors such as protein cross-linking may explain lower aortic distensibility in diabetes. MRI provides comprehensive vascular phenotyping in patients with type 2 diabetes and is likely to be useful in studies of disease progression and drug therapy.

Tousoulis D, Antoniades C, Bosinakou E, Kotsopoulou M, Tsoufis C, Marinou K, Charakida M, Stefanadi E, Vavuranakis M, Latsios G, Stefanadis C. 2007. Differences in inflammatory and thrombotic markers between unstable angina and acute myocardial infarction. Int J Cardiol, 115 (2), pp. 203-207. | Show Abstract | Read more

BACKGROUND: Unstable coronary syndromes are characterised by increased inflammatory process and endothelial activation. However, the underlying mechanisms of the acute coronary syndromes are still obscure. We evaluated the differences of inflammatory and thrombotic markers, at the acute phase of unstable angina (UA) and acute myocardial infarction (AMI). METHODS: The population of the study consisted of 216 subjects: 136 patients with UA, 57 patients with AMI and 23 healthy controls. Blood samples were taken by their admission to the hospital. Inflammatory and thrombotic markers were measured by ELISA. RESULTS: Patients with UA had significantly higher levels of interleukin-6 (IL-6), soluble vascular cells adhesion molecule (sVCAM-1) and von Willebrand factor (vWF) (p<0.05 vs controls), and lower levels of antithrombin III (ATIII) (p<0.01 vs controls) and protein C (PrtC) (p<0.05 vs controls). Similarly, patients with AMI had higher levels of IL-6, sVCAM-1, vWF and tissue plasminogen activator (tPA) (p<0.01 vs controls) and lower levels of ATIII (p<0.01 vs controls) and prtC (p<005 vs controls). Patients with AMI had significantly higher levels of vWF, tPA and sVCAM-1 compared to UA patients (p<0.05). CONCLUSIONS: Patients with unstable coronary syndromes had increased levels of IL-6, sVCAM-1 and vWF as well as decreased levels of ATIII and PrtC by their admission. However, patients with AMI had higher levels of all the endothelium-derived inflammatory (e.g. sVCAM-1) of thrombotic/fibrinolytic (e.g. tPA and vWF) markers, compared to those with UA. These findings imply that patients with myocardial infarction show further increase of endothelium-derived inflammatory and thrombotic markers compared to patients with unstable angina, in response to a similar proinflammatory stimuli.

Tousoulis D, Antoniades C, Vasiliadou C, Kourtellaris P, Koniari K, Marinou K, Charakida M, Ntarladimas I, Siasos G, Stefanadis C. 2007. Effects of atorvastatin and vitamin C on forearm hyperaemic blood flow, asymmentrical dimethylarginine levels and the inflammatory process in patients with type 2 diabetes mellitus. Heart, 93 (2), pp. 244-246. | Read more

Tousoulis D, Antoniades C, Charakida M, Toutouzas K, Trikas A, Stefanadi E, Siasos G, Latsios G, Stefanadis C. 2007. Cold pressor test as a marker for the detection of early stage coronary atherosclerosis. Int J Cardiol, 115 (1), pp. 120-122. | Read more

Vyssoulis GP, Tousoulis D, Antoniades C, Dimitrakopoulos S, Zervoudaki A, Stefanadis C. 2007. α-1 Microglobulin as a New Inflammatory Marker in Newly Diagnosed Hypertensive Patients American Journal of Hypertension, 20 (9), pp. 1016-1021. | Read more

Trikas A, Antoniades C, Latsios G, Vasiliadou K, Karamitros I, Tousoulis D, Tentolouris C, Stefanadis C. 2006. Long-term effects of levosimendan infusion on inflammatory processes and sFas in patients with severe heart failure. Eur J Heart Fail, 8 (8), pp. 804-809. | Show Abstract | Read more

BACKGROUND: The calcium sensitizer levosimendan improves myocardial contractility in patients with heart failure, although its effects on inflammation and apoptosis are unknown. AIM: To examine the effects of levosimendan on markers of inflammation and apoptosis, over a period of 30 d following a 24 h infusion, in patients with heart failure. METHODS: Thirty four patients with severe heart failure were randomised to receive a 24 h infusion of levosimendan or placebo, in a double-blind trial. Haemodynamic evaluation and blood sampling were performed at baseline, 24 h, 30 h, 48 h, 7 d and 30 d after the end of the infusion. RESULTS: Seven patients (1 levosimendan, 6 placebo), were excluded during follow-up. In the remaining 27 patients, levosimendan decreased serum IL-6 and sFAS, 24 h after the infusion (p<0.01 and p<0.05 vs baseline), an effect sustained for 7-30 d. Serum TNF-alpha and sTNF-R1 were decreased between 48 h (p<0.01 vs baseline for both) and 7 d (p<0.05 vs baseline for sTNF-R1) after infusion. Serum sTNF-R2 was decreased at 24 h (p<0.05 vs baseline) and remained lower than baseline for at least 7 d (p<0.05). CONCLUSIONS: These findings indicate that levosimendan decreases the expression of proinflammatory cytokines, TNF-alpha receptors and sFAS, immediately after infusion, an effect which persists for 7-30 d.

Andreou I, Tousoulis D, Tentolouris C, Antoniades C, Stefanadis C. 2006. Potential role of endothelial progenitor cells in the pathophysiology of heart failure: clinical implications and perspectives. Atherosclerosis, 189 (2), pp. 247-254. | Show Abstract | Read more

Endothelial dysfunction is thought to play a major role in the development and clinical complications of heart failure. Endothelial progenitor cells (EPCs) have been shown to provide an endogenous repair mechanism to counteract detrimental risk factor-induced effects and replace dysfunctional endothelium. The number and in vitro function of EPCs is altered in patients with heart failure, as a result of its pathophysiological mechanisms. EPCs could represent a substitutional marker to guide preventive or therapeutic interventions in this disease. Enhancing the number and functional capacity of EPCs with targeted interventions may elicit functional improvement in individuals with heart failure. However, the exact role of EPCs in heart failure and their potential therapeutic implications still remain to be elucidated.

Soubassi LP, Tousoulis D, Antoniades C, Lambrou S, Aggeli C, Chaniotis D, Soubassi S, Pitsavos C, Stefanadis C, Soubassis P, Toutouzas P. 2006. Acute improvement of aortic mechanics following hemodialysis in patients with chronic renal failure. Clin Cardiol, 29 (11), pp. 506-510. | Show Abstract | Read more

BACKGROUND: Evidence suggests that distensibility of the aorta is decreased in patients with end-stage renal failure, while the underlying mechanisms are unclear. HYPOTHESIS: The purpose of the study was to evaluate the distensibility of the aorta in patients at the end stage of chronic renal failure before and after hemodialysis (HD). METHODS: The diameter of the ascending aorta and distensibility were assessed in 48 patients on HD (31 men, 17 women, aged 45+/-14 years) and in 27 normal subjects (17 men, 10 women, aged 44+/-14 years). The diameter of the aorta was evaluated by M-mode in the parasternal long-axis view. RESULTS: Aortic distensibility was significantly lower in patients on HD before HD (1.9+/-0.7 cm(2) x dyn(-1) x 10(-6)) than in normal control subjects (3.8+/-1.0 cm(2) x dyn(-1) X 10(-6), p< 0.0001). After dialysis, it increased to 2.6+/-1.2 (p < 0.05 compared with baseline, p < 0.001 compared with controls). The change of aortic distensibility correlated with age (R(2) = 0.629 p < 0.001) and ultrafiltration volume (R(2) = 0.168, p < 0.01). CONCLUSIONS: Aortic distensibility in patients with end-stage renal disease is significantly lower than in normal subjects, and it is significantly improved after HD.

Tousoulis D, Antoniades C, Koumallos N, Marinou K, Stefanadi E, Latsios G, Stefanadis C. 2006. Novel therapies targeting vascular endothelium. Endothelium, 13 (6), pp. 411-421. | Show Abstract | Read more

Endothelial dysfunction has been identified as a major mechanism involved in all the stages of atherogenesis. Evaluation of endothelial function seems to have a predictive role in humans, and therapeutic interventions improving nitric oxide bioavailability in the vasculature may improve the long-term outcome in healthy individuals, high-risk subjects, or patients with advanced atherosclerosis. Several therapeutic strategies are now available, targeting both the synthesis and oxidative inactivation of nitric oxide (NO) in human vasculature. Statins seem to be currently the most powerful category of these agents, improving endothelial function and decreasing cardiovascular risk after long-term administration. Other cardiovascular agents improving endothelial function in humans are angiotensin-converting enzyme inhibitors/angiotensin receptors blockers, which increase NO bioavailability by modifying the rennin-angiotensin-aldosterone system. Newer therapeutic approaches targeting endothelial dysfunction in specific disease states include insulin sensitizers, L-arginine (the substrate for endothelial NO synthase [eNOS]) as well as substances that target eNOS "coupling," such as folates or tetrahydrobiopterin. Although there are a variety of strategies to improve NO bioavailability in human endothelium, it is still unclear whether they have any direct benefit at a clinical level.

Antoniades C, Tousoulis D, Marinou K, Vasiliadou C, Tentolouris C, Bouras G, Pitsavos C, Stefanadis C. 2006. Asymmetrical dimethylarginine regulates endothelial function in methionine-induced but not in chronic homocystinemia in humans: effect of oxidative stress and proinflammatory cytokines. Am J Clin Nutr, 84 (4), pp. 781-788. | Show Abstract

BACKGROUND: Homocystinemia is a metabolic abnormality associated with endothelial dysfunction and increased cardiovascular disease risk. The underlying mechanisms of these effects, however, are obscure. OBJECTIVE: We examined the effect of asymmetrical dimethylarginine (ADMA) on endothelial dysfunction in methionine-induced and chronic homocystinemia and evaluated the regulatory role of oxidative stress and proinflammatory cytokines on the release of ADMA. DESIGN: In this double-blind, placebo-controlled parallel group study, 30 subjects of both sexes (15 with homocystinemia and 15 healthy controls) underwent methionine loading, with simultaneous administration of a combination of vitamin C (2 g) plus alpha-tocopherol (800 IU) or placebo. Endothelial function in forearm resistance vessels and concentrations of ADMA, oxidized LDL, and proinflammatory cytokines were determined at baseline and 4 h after methionine loading. RESULTS: Both chronic and methionine-induced homocystinemia were associated with increased oxidized LDL (P < 0.01), higher expression of the proinflammatory cytokine interleukin 6 (P < 0.05), and endothelial dysfunction (P < 0.01). Although ADMA rapidly increased in acute homocystinemia (P < 0.01) and was correlated with forearm hyperemic response at 4 h after methionine loading (r = -0.722, P = 0.0001), it was not higher in subjects with high versus low fasting homocysteine. High-dose antioxidant treatment prevented methionine-induced elevation of oxidized LDL and interleukin 6 but failed to prevent the increase in ADMA or endothelial dysfunction. CONCLUSIONS: Both chronic and methionine-induced homocystinemia are characterized by increased oxidative stress and proinflammatory cytokines, which may contribute to the development of endothelial dysfunction. However, the ADMA pathway is activated only in acute homocystinemia by mechanisms not mediated by oxidized LDL or proinflammatory stimuli.

Antoniades C, Shirodaria C, Warrick N, Cai S, de Bono J, Lee J, Leeson P, Neubauer S, Ratnatunga C, Pillai R et al. 2006. 5-methyltetrahydrofolate rapidly improves endothelial function and decreases superoxide production in human vessels: effects on vascular tetrahydrobiopterin availability and endothelial nitric oxide synthase coupling. Circulation, 114 (11), pp. 1193-1201. | Show Abstract | Read more

BACKGROUND: The circulating form of folic acid, 5-methyltetrahydrofolate (5-MTHF), may have beneficial effects on endothelial function; however, its mechanisms of action remain uncertain. Decreased nitric oxide (NO) bioavailability and increased vascular superoxide production in vascular disease states are due in part to endothelial NO synthase (eNOS) uncoupling related to deficiency of the eNOS cofactor tetrahydrobiopterin (BH4), but whether this mechanism is important in human atherosclerosis and represents a rational therapeutic target remains unclear. We hypothesized that 5-MTHF would improve endothelial function by decreasing superoxide and peroxynitrite production and by improving eNOS coupling, mediated by BH4 availability. METHODS AND RESULTS: Vascular superoxide/peroxynitrite production and vasomotor responses to acetylcholine and bradykinin were determined in saphenous veins and internal mammary arteries from 117 patients undergoing CABG. The effects of 5-MTHF were examined ex vivo (n = 61) by incubating vessels with 5-MTHF (1 to 100 micromol/L) and in vivo by intravenous infusion of 5-MTHF or placebo before vessel harvest (n = 56). 5-MTHF improved NO-mediated endothelium-dependent vasomotor responses and reduced vascular superoxide, both ex vivo and in vivo. These changes were not explained by direct superoxide scavenging by 5-MTHF in vitro or by changes in plasma total homocysteine in vivo. Rather, 5-MTHF was a strong peroxynitrite scavenger and increased vascular BH4 and the BH4/total biopterin ratio. Furthermore, 5-MTHF reversed eNOS uncoupling, as assessed by NG-nitro-l-arginine methyl ester-inhibitable superoxide production, increased the eNOS dimer:monomer ratio, and enhanced eNOS activity. CONCLUSIONS: 5-MTHF has beneficial effects on endothelial function and vascular superoxide production in human atherosclerosis, by preventing peroxynitrite-mediated BH4 oxidation and improving eNOS coupling.

Tousoulis D, Antoniades C, Koumallos N, Stefanadis C. 2006. Pro-inflammatory cytokines in acute coronary syndromes: from bench to bedside. Cytokine Growth Factor Rev, 17 (4), pp. 225-233. | Show Abstract | Read more

Cytokines are produced in a variety of tissues and regulate the expression of a number of inflammatory molecules, leading to destabilization and finally rupture of vulnerable atheromatic plaques. They also participate in the pathophysiology of acute coronary syndromes (ACS) by direct effects on myocardial contractility and apoptosis. At a clinical level, circulating cytokines have a prognostic role since they are useful markers predicting future coronary events in patients with advanced atherosclerosis and in patients after ACS.

Koumallos N, Antoniades C, Tousoulis D, Shirodaria C, Stefanadis C. 2006. Levosimendan: a novel agent in heart failure. Recent Pat Cardiovasc Drug Discov, 1 (2), pp. 185-191. | Show Abstract | Read more

Heart failure is characterised by decreased cardiac output, which results in the development of both peripheral hypoperfusion and pulmonary congestion and can lead to the development of acute pulmonary edema. The primary objective in treating a patient with decompensated heart failure is hemodynamic stabilization, which is usually achieved by inotropic support. Classic inotropic agents provide short-term hemodynamic improvement, but their use has been correlated with poor prognosis. Levosimendan, a new calcium sensitizer, offers hemodynamic and symptomatic improvement without increasing cAMP and intracellular calcium concentrations. This agent improves contractility without increasing the risk of cardiac events such as arrhythmias. By combining a positive inotropic action mediated via calcium sensitization and a vasodilatory effect via ATP-dependent potassium channels, it appears to be superior than classic positive inotropic agents. Furthermore, it seems to have prolonged benefit in heart failure patients, and it also has anti-inflammatory and antiapoptotic properties. In conclusion, levosimendan seems to be a particularly promising agent for the treatment of decompensated heart failure, as in addition to improving cardiac output, it has a more favorable side-effect profile than classic inotropic agents, and it affects multiple pathways with key role in the pathophysiology of heart failure.

Antoniades C, Tousoulis D, Vasiliadou C, Stefanadi E, Marinou K, Stefanadis C. 2006. Genetic polymorphisms of platelet glycoprotein Ia and the risk for premature myocardial infarction: effects on the release of sCD40L during the acute phase of premature myocardial infarction. J Am Coll Cardiol, 47 (10), pp. 1959-1966. | Show Abstract | Read more

OBJECTIVES: The aim of this research was to evaluate the effect of genetic polymorphisms C807T and G1648A of platelet glycoprotein Ia (GPIa), on the risk for myocardial infarction (MI) and on the release of soluble CD40 ligand (sCD40L) during the acute phase of MI and one year after the event. BACKGROUND: C807T and G1648A polymorphisms affect the density of GPIa on platelet surface, but their effect on the risk for MI and the release of sCD40L is unknown. METHODS: The study population consisted of 219 patients with premature MI and 389 controls. One year after the event, 67 patients and 232 controls were recalled for the follow-up study. RESULTS: The risk for MI in 807TT was 2.296 (95% confidence interval [CI]: 1.187 to 4.440) p < 0.05 versus CC + CT, 2.269 (95% CI: 1.085 to 4.745) p < 0.05 versus CC, and 2.135 (95% CI: 1.080 to 4.219) p < 0.05 versus CT. During the acute phase of MI, sCD40L was higher in 807CT + TT compared with 807CC (p < 0.01), an effect persisting after one year (p < 0.01). The carriage of 807T allele was an independent predictor for sCD40L during the acute phase of MI (beta = 9.442 [standard error (SE): 2.526], p = 0.001) and in the same patients one year later (beta = 8.282 [SE: 2.044], p = 0.001). In healthy individuals, 807T allele was associated with higher sCD40L levels compared with 807CC (p < 0.05), only among those with von Willebrand factor greater than or equal to median. CONCLUSIONS: Genetic polymorphism C807T increases the risk for premature MI. 807T allele is an independent predictor for sCD40L levels during the acute phase of premature MI as well as one year after the event, while it is associated with elevated sCD40L levels in healthy subjects, only in the presence of high von Willebrand levels.

Antoniades C, Tousoulis D, Marinou K, Stefanadi E, Ntarladimas I, Latsios G, Konniari K, Papageorgiou N, Siasos G, Stefanadis C. 2006. Effects of lipid profile on forearm hyperemic response in young subjects. Hellenic J Cardiol, 47 (3), pp. 152-157. | Show Abstract

INTRODUCTION: The role of lipids in atherogenesis is now well established. However, the exact mechanisms by which different lipoproteins affect endothelial function and induce atherogenesis are still not well understood. In the present study we examined the effect of lipid profile on forearm vasodilatory response to reactive hyperemia, an index of endothelial function, in a cohort of young, low-risk adults. METHODS: One hundred sixty seven healthy subjects were included in the study. The effect of total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, apolipoprotein (apo)-A1, apo-B and apo-E on endothelial function and inflammatory process was examined. Endothelial function was evaluated by determining forearm vasodilatory response to reactive hyperemia (RH%) using gauge-strain plethysmography. RH% was defined as the % change of forearm blood flow from baseline to the maximum flow during post-ischemic hyperemia. Endothelium independent dilatation in response to nitroglycerin (NTG%) was defined as the % change of forearm blood flow from baseline to the maximum flow after sublingual nitroglycerin administration. RESULTS: RH% was correlated with HDL (r = 0.267, p = 0.001), LDL (r = 0.355, p = 0.0001), triglycerides (rho = -0.366, p = 0.0001), apo-Al (r = 0.240, p = 0.004) and apo-B (r = -0.277, p = 0.005). NTG% was not affected by serum lipid levels. In multivariate linear regression, LDL (beta = -0.217 [SE: 0.098], p = 0.028), apo-A1 (beta = 0.277 [SE: 0.124], p = 0.027) and age (beta = 0.916 [SE:0.369], p = 0.015) were independent predictors for RH% in this population (R2 for the model: 0.243, p = 0.0001). CONCLUSIONS: Elevated lipid levels decrease forearm vasodilatory response to reactive hyperemia. Apolipoproteins, and especially apo-Al, are important determinants of endothelial function in these subjects, independently of LDL, HDL and triglycerides, implying that full measurement of the lipid profile may be of great importance in risk stratification of young individuals.

Tousoulis D, Antoniades C, Katsi V, Bosinakou E, Kotsopoulou M, Tsioufis C, Stefanadis C. 2006. The impact of early administration of low-dose atorvastatin treatment on inflammatory process, in patients with unstable angina and low cholesterol level. Int J Cardiol, 109 (1), pp. 48-52. | Show Abstract | Read more

BACKGROUND: Lipid-lowering agents are known to reduce long-term mortality in patients with stable angina or multiple risk factors. However, the effects of lipid-lowering treatment on inflammatory process during and immediately after the acute phase of unstable angina remain unclear. In this study we assessed the effects of low-dose atorvastatin treatment, on inflammatory process in patients admitted for unstable angina with low cholesterol level. METHODS: Forty-seven normocholesterolemic patients with unstable angina were randomized into two groups, and received atorvastatin 10 mg/day (n = 24) or no statin (n = 23) for 6 weeks. Circulating levels of inteleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-alpha) and soluble vascular cell adhesion molecule (sVCAM-1) were measured by their admission, and at the 1st and 6th week of the study. RESULTS: Serum levels of MCP-1 and sVCAM-1 were significantly increased in the control group (p < 0.05) while remained unaffected in the atorvastatin-treated group six weeks after admission. However, IL-6 and TNF-alpha levels were similarly decreased in both atorvastatin-treated and control groups. CONCLUSION: Low-dose atorvastatin treatment modifies inflammatory process in patients with unstable angina and low cholesterol level, an effect seen at 6 weeks but not 1 week after admission.

Tousoulis D, Antoniades C, Stefanadis C. 2006. Statins and antioxidant vitamins: should co-administration be avoided? J Am Coll Cardiol, 47 (6), pp. 1237. | Read more

Antoniades C, Tousoulis D, Vasiliadou C, Pitsavos C, Toutouza M, Tentolouris C, Marinou K, Stefanadis C. 2006. Genetic polymorphisms G894T on the eNOS gene is associated with endothelial function and vWF levels in premature myocardial infarction survivors. Int J Cardiol, 107 (1), pp. 95-100. | Show Abstract | Read more

BACKGROUND: Genetic polymorphism G894T on endothelial nitric oxide synthase (eNOS) gene has been associated with endothelial dysfunction in young smokers, but its role in the pathogenesis of MI is obscure. We examined the effect of G894T polymorphism on endothelial function, on markers of endothelial cells injury and activation such as von Willebrand factor (vWF) and on serum levels of proinflammatory cytokines such as interleukins 6 (IL-6) and 1b (IL-1b), in young myocardial infarction (MI) survivors. METHODS: The study population consisted of 56 patients with a history of premature MI. The forearm blood flow (FBF) was measured by using strain-gauge plethysmography during reactive hyperemia and after sublingual administration of nitroglycerin. G894T polymorphism was determined by polymerase chain reaction (PCR), while plasma vWF and serum IL1b and IL-6 levels were determined with ELISA. RESULTS: There was no significant difference in resting FBF and in the responses to nitroglycerin between the genotypes. However, the presence of T allele (GT+TT, n=35) was associated with decreased FBF during reactive hyperemia (10.23+/-0.70 ml/100ml tissue/min) and decreased forearm vasodilatory response to reactive hyperemia (54.28+/-4.81%) compared to GG (13.82+/-0.92 ml/100 ml tissue/min and 83.92+/-9.89% respectively, p<0.01 for both). Carriers of the T allele had also higher levels of vWF (79.66+/-5.56%) compared to GG (60.94+/-5.27% p<0.05). However, no significant difference was observed in IL-1b and IL-6 serum levels between the genotypes (p=ns for both). CONCLUSIONS: The presence of 894T allele on eNOS gene is associated with impaired endothelial function and higher levels of von Willebrand factor in relatively young patients with myocardial infarction. This finding implies that genetic polymorphism G894T on eNOS may affect endothelial function in patients with a history of premature myocardial infarction.

Tousoulis D, Bosinakou E, Kotsopoulou M, Antoniades C, Katsi V, Stefanadis C. 2006. Effects of early administration of atorvastatin treatment on thrombotic process in normocholesterolemic patients with unstable angina. Int J Cardiol, 106 (3), pp. 333-337. | Show Abstract | Read more

BACKGROUND: Although statin-treatment during the acute phase of unstable coronary syndromes improve the outcome their effects on thrombosis/fibrinolysis system in normocholesterolemic patients admitted with unstable angina remain obscure. We assessed the effects of short-term atorvastatin treatment on thrombotic/fibrinolysis markers in normocholesterolemic in patients with unstable angina. METHODS: Forty-five patients with unstable angina were allocated into two groups to receive atorvastatin 10 mg/day (n = 24) or no statin (n = 21) for 6 weeks. Circulating levels of von Willebrand Factor (vWF), factor V (fV), protein C (prC), tissue plasminogen activator (tPA) and antithrombin III (ATIII) were measured by enzyme linked immunosorbent assay, by the patients admission and at the 1st and 6th week of the study. RESULTS: After 1 week of treatment, a significant increase of ATIII (p < 0.05), fV (p < 0.01) and vWF (p < 0.05) was found in the control group, but not in atorvastatin-treated group. Similarly, at 6 weeks after admission, plasma levels of ATIII were still significantly higher than at baseline in controls (p < 0.05), but not in atorvastatin-treated group. Plasma levels of PrtC were significantly increased in both controls (p < 0.01) and atorvastatin-treated patients (p < 0.05) at 1 week, while remained unaffected in atorvastatin-treated group at 6th week. There was no significant difference in the variations of plasma levels of tPA, PrtS and fVII between the two groups at 1 and 6 weeks after admission. CONCLUSIONS: In normocholesterolemic patients admitted with unstable angina the early administration of atorvastatin, significantly affects von Willebrand factor levels and the expression of liver-derived components of both thrombosis and fibrinolysis system.

Tousoulis D, Antoniades C, Stefanadis C. 2006. Nitric oxide in coronary artery disease: effects of antioxidants European Journal of Clinical Pharmacology, 62 (S1), pp. 101-107. | Read more

Tousoulis D, Antoniades C, Vassiliadou C, Toutouza M, Pitsavos C, Tentolouris C, Trikas A, Stefanadis C. 2005. Effects of combined administration of low dose atorvastatin and vitamin E on inflammatory markers and endothelial function in patients with heart failure. Eur J Heart Fail, 7 (7), pp. 1126-1132. | Show Abstract | Read more

BACKGROUND: Heart failure has been associated with impaired endothelial function, increased inflammatory process and elevated oxidative stress status. Both statins and vitamin E separately improve endothelial function in patients with hypercholesterolemia and/or advanced atherosclerosis. AIM: To evaluate the effect of atorvastatin alone or in combination with vitamin E on endothelial function and serum levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha) and vascular cells adhesion molecule (sVCAM-1) in patients with ischemic heart failure. METHODS: Thirty-eight male patients with ischemic cardiomyopathy were randomly divided into three groups and received either atorvastatin 10 mg/day (n = 14), a combination of atorvastatin 10 mg/day plus vitamin E 400 IU/day (n = 12), or no statin or antioxidant treatment (n=12, controls) for 4 weeks. Forearm blood flow (FBF) was measured using venous occlusion strain-gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) or to nitrate (NTG%) was defined as the percent change of FBF from rest to the maximum flow during reactive hyperemia or after nitrate administration, respectively. RESULTS: RH% was significantly improved in both the atorvastatin-treated (p < 0.01) and atorvastatin plus vitamin E groups (p < 0.05), but the increase was significantly higher in the atorvastatin-treated group (p < 0.05). Serum levels of IL-6, TNF-alpha and sVCAM-1 were decreased in the atorvastatin-treated group (p < 0.05 for all), but remained unaffected in the other two groups (p = NS for all). CONCLUSIONS: Low dose atorvastatin treatment improves endothelial function and reduces the expression of proinflammatory cytokines and adhesion molecules in patients with ischemic heart failure, an effect partly depressed by vitamin E.

Aggeli C, Antoniades C, Cosma C, Chrysohoou C, Tousoulis D, Ladis V, Karageorga M, Pitsavos C, Stefanadis C. 2005. Endothelial dysfunction and inflammatory process in transfusion-dependent patients with beta-thalassemia major. Int J Cardiol, 105 (1), pp. 80-84. | Show Abstract | Read more

BACKGROUND: Beta-thalassemia major is associated with increased cardiovascular risk, although the underlying mechanisms remain unclear. We examined endothelial function and serum levels of inflammatory mediators in transfusion-dependent patients with beta-thalassemia major. METHODS: The study population consisted of 67 patients with homozygous beta-thalassemia major, (aged 24.6+/-0.7 years) and 71 healthy age and sex matched controls. Forearm blood flow was measured with gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) or to nitrate (NTG%) was expressed as the percentage change of forearm blood flow from baseline to the maximum flow during reactive hyperemia or sublingual nitroglycerin, respectively. Serum levels of interleukin 6 (IL-6), soluble vascular cell adhesion molecule (sVCAM-1) and soluble intercellular adhesion molecule (sICAM-1) were determined with ELISA. RESULTS: Patients had significantly lower levels of total cholesterol (125+/-4.5 vs. 207+/-7 mg/ml, p<0.01), ApoA1 (120+/-3 vs. 129+/-5 mg/ml, p<0.05), ApoB (60.5+/-2 vs. 95+/-4 mg/ml, p<0.01), ApoE (3+/-2 vs. 4+/-0.2 mg/ml, p<0.01) and Lp(a) (7.9+/-1.3 vs. 14.5+/-3.2 mg/ml, p<0.01) than controls. IL-6 levels were significantly higher in patients (3.03+/-0.31 pg/ml) than controls (1.15+/-0.15 pg/ml, p<0.01). Similarly, sVCAM-1 and sICAM-1 levels were significantly higher in patients (513+/-31 and 368+/-25.5 ng/ml, respectively) than controls (333+/-13.8 and 272+/-14.05 ng/ml, respectively, p<0.01 for both). Maximum hyperemic forearm blood flow and RH% were lower in patients (7.1+/-0.3 ml/100 ml tissue/min and 49+/-2.8%, respectively) than controls (8.26+/-0.32 ml/100 ml tissue/min and 86.3+/-5.57%, respectively, p<0.01 for both). CONCLUSIONS: Beta-thalassemia major is associated with impaired endothelial function and increased levels of IL-6, sVCAM-1 and sICAM-1, suggesting a potential role of inflammation and endothelial dysfunction in the complications of the disease.

Antoniades C, Tousoulis D, Stefanadis C. 2005. Letter regarding article by Becker et al, "Hyperhomocysteinemia, a cardiac metabolic disease: role of nitric oxide and the p22phox subunit of NADPH oxidase". Circulation, 112 (15), pp. e266. | Read more

Tousoulis D, Xenakis C, Tentolouris C, Davies G, Antoniades C, Crake T, Stefanadis C. 2005. Effects of vitamin C on intracoronary L-arginine dependent coronary vasodilatation in patients with stable angina. Heart, 91 (10), pp. 1319-1323. | Show Abstract | Read more

OBJECTIVE: To assess the effects of intravenous vitamin C administration on the vasomotor responses to intracoronary L-arginine infusion in epicardial coronary arteries. METHODS: 28 patients with coronary artery disease and stable angina were enrolled in the study. Eight patients received intracoronary infusions of 150 micromol/min L-arginine before and after intravenous infusion of vitamin C, 10 patients received intracoronary infusions of 150 micromol/min L-arginine before and after intravenous infusion of normal saline, and 10 patients received intracoronary normal saline before and after intravenous infusion of vitamin C. The diameter of proximal and distal coronary artery segments was measured by quantitative angiography. RESULTS: Infusion of L-arginine caused significant dilatation of both proximal (4.87 (0.96)%, p < 0.01 v normal saline) and distal (6.33 (1.38)%, p < 0.01 v normal saline) coronary segments. Co-infusion of vitamin C and L-arginine dilated proximal coronary segments by 8.68 (1.40)% (p < 0.01 v normal saline, p < 0.01 v L-arginine) and distal segments by 13.07 (2.15)% (p < 0.01 v normal saline, p < 0.01 v L-arginine). Intravenous infusion of vitamin C caused a borderline increase in proximal and distal coronary segment diameters (1.93 (0.76)% and 2.09 (1.28)%, respectively, not significant). CONCLUSIONS: L-arginine dependent coronary segment vasodilatation was augmented by the antioxidant vitamin C in patients with coronary artery disease. Thus, vitamin C may have beneficial effects on nitric oxide bioavailability induced by L-arginine.

Antoniades C, Tousoulis D, Vasiliadou C, Pitsavos C, Chrysochoou C, Panagiotakos D, Tentolouris C, Marinou K, Koumallos N, Stefanadis C. 2005. Genetic polymorphism on endothelial nitric oxide synthase affects endothelial activation and inflammatory response during the acute phase of myocardial infarction. J Am Coll Cardiol, 46 (6), pp. 1101-1109. | Show Abstract | Read more

OBJECTIVES: This study sought to evaluate the effect of genetic polymorphism G894T on endothelial nitric oxide synthase (eNOS); on the risk for myocardial infarction (MI); and on the release of von Willebrand factor (vWF), interleukin (IL)-6, IL-1b, and oxidized low-density lipoprotein (ox-LDL) levels during the acute phase of MI and one year after the event. BACKGROUND: Genetic polymorphism G894T on eNOS has been associated with increased cardiovascular risk. However, its role during the acute phase of MI is unknown. METHODS: The study population consisted of 228 patients with a first event of premature MI and 519 matched control patients. One year after the event, 61 patients and 205 control patients were recalled for the follow-up study. Blood sampling was performed during the acute phase and after one year. RESULTS: The risk for MI in 894TT was 1.992 (95% confidence interval [CI], 1.131 to 3.485), p < 0.05 versus GG+GT; 2.038 (95% CI, 1.125 to 3.695), p < 0.05 versus GG; and 2.009 (95% CI, 1.106 to 3.651), p < 0.05 versus GT. During the acute phase, vWF was higher in GT+TT (121.02 +/- 5.47%) versus GG (84.6 +/- 7.1%, p < 0.01), an effect persisting after one year (90.4 +/- 3.8 vs. 73.1 +/- 4.6%, p < 0.01). During the acute phase, GT+TT had higher ox-LDL and IL-6 (131.2 +/- 6.4 IU/l and 8.5 +/- 0.7 pg/ml) compared with GG (101.7 +/- 9.64 IU/l and 6.2 +/- 0.8 pg/ml, p < 0.05 for both), but no difference was found at one year. CONCLUSIONS: G894T polymorphism on the eNOS gene increases the risk for premature MI and modifies the response of vascular endothelium during the acute phase of MI by affecting the release of vWF, IL-6, and oxidative stress status, an effect diminished one year after the event.

Brili S, Tousoulis D, Antoniades C, Aggeli C, Roubelakis A, Papathanasiu S, Stefanadis C. 2005. Evidence of vascular dysfunction in young patients with successfully repaired coarctation of aorta. Atherosclerosis, 182 (1), pp. 97-103. | Show Abstract | Read more

It is well documented that in patients with coarctation of the aorta life expectancy is not normal even after successful coarctation repair (SCR), primarily due to cardiovascular events. We examined endothelial function in the forearm circulation, the mechanical properties and intima/media thickness in carotid and femoral arteries and the inflammatory process in normotensive patients, after coarctation repair. Fifteen patients, 29+/-2 years old, 12+/-2.9 years after SCR and 16 age- and sex-matched controls were enrolled in our study. Forearm blood flow was determined by gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia was expressed as the %change from baseline to post-reactive hyperemia blood flow. High resolution ultrasound was used for determination of intima/media thickness and elastic properties of carotid and femoral arteries. Serum levels of soluble vascular adhesion molecule 1 (sVCAM-1), intercellular adhesion molecule 1 (sICAM-1), E-selectin, and interleukines 1b (IL-1b) and 6 (IL-6) were determined by ELISA. Reactive hyperemia was significantly decreased in patients compared to controls (p<0.01). Patients with SCR had higher intima/media thickness and decreased distensibility in the carotid arteries than controls (p<0.01 for both). Serum levels of sICAM-1, sSVCAM-1, E-selectin and IL-1b were higher in SCR group than in controls (p<0.05 for all). Adult patients after SCR have impaired endothelial function in the forearm circulation, increased intima/media thickness, decreased distensibility in the carotid arteries and increased levels of proinflammatory cytokines and adhesion molecules than healthy controls. These results may partly explain the high incidence of coronary artery disease in patients with repaired coarctation of the aorta.

Karas SM, Parissis JT, Antoniades C, Loulias A. 2005. A rare case of large mediastinal germ cell tumor detected by echocardiography. Int J Cardiol, 101 (1), pp. 159-161. | Show Abstract | Read more

We describe a rare case of a large mediastinal germ cell tumor detected by modified views of transthoracic echocardiography. CT scanning and histological findings after tumor resection confirmed diagnosis. This case demonstrates the clinical importance of echocardiography in diagnosis of extra-cardiac masses.

Tousoulis D, Antoniades C, Stefanadis C. 2005. Evaluating endothelial function in humans: a guide to invasive and non-invasive techniques. Heart, 91 (4), pp. 553-558. | Read more

Trikas A, Papathanasiou S, Tousoulis D, Tentolouris K, Vasiliadou K, Antoniades C, Latsios G, Stefanadis C. 2005. Left atrial function, cytokines and soluble apoptotic markers in mitral stenosis: effects of valvular replacement. Int J Cardiol, 99 (1), pp. 111-115. | Show Abstract | Read more

BACKGROUND: Patients with mitral stenosis (MS) and heart failure (HF) are characterized by changes in the left atrial (LA) function and activation of the apoptotic process. The purpose of the present study was the evaluation of the effect of mitral valve replacement on the LA function, on inflammatory process and apoptotic markers in patients with MS and HF. METHODS: We studied 30 patients with MS and HF (15 in NYHA III-IV and 15 in NYHA IV) in sinus rhythm (mean age 56.2 +/- 4.6 years), and 20 age and gender matched healthy volunteers. Blood samples were obtained before and 6 months after surgical mitral valve replacement, and plasma levels of soluble Fas/APO-1 receptor (sFas), tumor necrosis factor-alpha (TNF-a) and interleukin-6 (IL-6) were measured. Echocardiographically, LA volumes were measured at mitral valve opening (Vmax), at the onset of left atrial systole (P wave of the electrocardiogram, Vp) and at the mitral valve closure (Vmin). LA contractile function was assessed by the LA active emptying fraction (ACTEF). RESULTS: After mitral valve replacement, TNF-a, IL-6 and sFas levels, as well as the Vmax LA volume, were significantly reduced (p < 0.05). ACTEF showed a significant postoperative decrease (0.29 +/- 0.09 vs. 0.23 +/- 0.06, p < 0.01) and it was significantly correlated with sFas (r = -0.88, p = 0.001), TNF-a (r = -0.81, p = 0.001) and IL-6 (r = -0.74, p = 0.001) levels. CONCLUSION: The present findings indicate that mitral valve replacement in patients with mitral valve stenosis, reduces the size of the left atrium, improves left atrial contractile function and depresses inflammatory and apoptotic process.

Tousoulis D, Antoniades C, Bosinakou E, Kotsopoulou M, Pitsavos C, Vlachopoulos C, Panagiotakos D, Stefanadis C. 2005. Effects of atorvastatin on reactive hyperemia and inflammatory process in patients with congestive heart failure. Atherosclerosis, 178 (2), pp. 359-363. | Show Abstract | Read more

Purpose of the study was to investigate whether short-term atorvastatin treatment improves endothelial function and affects inflammatory process in patients with heart failure (HF) and normal cholesterol levels. HF is characterized by endothelial dysfunction and increased inflammatory process, while statins restore endothelial function having also anti-inflammatory effects in hypercholesterolemic patients. We investigated the effect of 4-week atorvastatin treatment (10 mg/day) on endothelial function and inflammatory markers in patients with HF and cholesterol levels <220 mg/dl. Patients were randomly allocated into groups and received atorvastatin (n=19) or no statin (n=19). Forearm blood flow was measured using gauge-strain plethysmography. Serum levels of tumor necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6), and soluble vascular cell adhesion molecule (sVCAM-1) were determined with ELISA. Data are expressed as median [25th-75th percentile]. Forearm vasodilatory response to reactive hyperemia was significantly improved in atorvastatin-treated patients (from 38.1% [32.0-59.1] to 70.0% [61.1-106.3], P<0.01), while it remained unaffected in the control group. Levels of IL-6, TNF-alpha and sVCAM-1 were decreased in atorvastatin-treated group (from 7.8 pg/ml [4.8-9.5], 3.2 pg/ml [2.7-4.8] and 595 ng/ml [440-810] to 5.6 pg/ml [2.5-9.0], 2.8 pg/ml [2.0-3.6] and 289 ng/ml [169-368], respectively, P<0.05 for all) but not in the control group. These findings indicate that atorvastatin may improve forearm vasodilatory response to reactive hyperemia and depress inflammatory process in patients with heart failure and normal baseline cholesterol levels.

Tousoulis D, Antoniades C, Bosinakou E, Kotsopoulou M, Tsioufis C, Tentolouris C, Trikas A, Pitsavos C, Stefanadis C. 2005. Effects of atorvastatin on reactive hyperaemia and the thrombosis-fibrinolysis system in patients with heart failure. Heart, 91 (1), pp. 27-31. | Show Abstract | Read more

OBJECTIVE: To investigate the effects of short term atorvastatin treatment on forearm vasodilatory response to reactive hyperaemia (RH%) and on components of the thrombosis-fibrinolysis system (antithrombin III, proteins and S, factors V and VII, von Willebrand factor, tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAI-1)) in patients with heart failure. PATIENTS AND METHODS: 35 patients with heart failure were enrolled in this study; 17 patients received atorvastatin 10 mg/day and 18 patients received no statin for four weeks. Forearm blood flow (FBF) was measured by venous occlusion strain gauge plethysmography. RH% and forearm vasodilatory response to nitrate were defined as the percentage change of FBF from rest to the maximum flow during reactive hyperaemia and after nitrate administration, respectively. Plasma concentrations of antithrombin III, protein C, protein S, factor V, factor VII, von Willebrand factor, tPA, and PAI-1 were determined before and after treatment. RESULTS: Maximum hyperaemic FBF remained unchanged in both groups. Baseline FBF was slightly but not significantly decreased in the atorvastatin treated group. RH% was significantly increased only in the atorvastatin treated group, from mean (SD) 42.44 (18.9)% to 83.7 (36.1)% (p < 0.01). Plasma concentrations of antithrombin III (from mean (SD) 81.7 (11.37)% to 73.5 (13.8)%), protein C (from mean (SD) 88.3 (26.9)% to 63.9 (25.0)%), factor V (from mean (SD) 126.2 (33.4)% to 94.9 (29.8)%), tPA (from median (25th-75th percentile) 11.68 (8.60-20.95) ng/ml to 10.30 (8.65-15.12) ng/ml), and PAI-1 (from median (25th-75th percentile) 3.10 (2.15-4.40) IU/l to 1.90 (0.75-3.0) IU/l) were significantly decreased in the atorvastatin treated group (p < 0.05) but not in the control group. Plasma concentrations of von Willebrand factor, factor VII, and protein S remained unaffected in both groups. CONCLUSION: Atorvastatin did not change the maximum hyperaemic flow, although it decreased plasma concentrations of antithrombin III, protein C, factor V, tPA, and PAI-1 in patients with heart failure. Therefore, short term treatment with atorvastatin may affect the expression of both endothelium and liver derived components of the thrombosis-fibrinolysis system in patients with heart failure.

Marinou K, Antoniades C, Tousoulis D, Pitsavos C, Goumas G, Stefanadis C. 2005. Homocysteine: a risk factor for coronary artery disease? Hellenic J Cardiol, 46 (1), pp. 59-67.

Antoniades C, Tousoulis D, Vasiliadou C, Marinou K, Tentolouris C, Ntarladimas I, Stefanadis C. 2004. Combined effects of smoking and hypercholesterolemia on inflammatory process, thrombosis/fibrinolysis system, and forearm hyperemic response. Am J Cardiol, 94 (9), pp. 1181-1184. | Show Abstract | Read more

The combined effects of smoking and hypercholesterolemia on the inflammatory process, the thrombosis/fibrinolysis system, and forearm hyperemic response were investigated. It was shown that smokers with hypercholesterolemia (n = 25) had a reduced and delayed forearm hyperemic response compared with healthy smokers (n = 24), patients with hypercholesterolemia (n = 26), and healthy controls (n = 75; p <0.01 for all). This phenomenon was associated with a respective increase in the inflammatory process and changes in the thrombosis/fibrinolysis system.

Chrysohoou C, Panagiotakos DB, Pitsavos C, Antoniades C, Skoumas J, Brown M, Stefanadis C. 2004. Evidence for association between endothelial nitric oxide synthase gene polymorphism (G894T) and inflammatory markers: the ATTICA study. Am Heart J, 148 (4), pp. 733-738. | Show Abstract | Read more

BACKGROUND: We evaluated the effect of the point mutation of guanine to thymine at nucleotide position 894 (G894T) of the endothelial nitric oxide synthase (eNOS) gene on inflammatory and oxidative stress markers. METHODS: We studied genetic information from 270 men (18-87 years old) and 325 women (18-89 years old). Participants without any clinical evidence of cardiovascular or other atherosclerotic disease were randomly selected from the general population according to the age-sex distribution of Athens greater area. Genomic DNA was extracted from 2 to 5 mL of fresh or frozen whole blood using standard methods. RESULTS: The DNA analysis showed that 10.6% of the participants were Asp-homozygotes (Asp/Asp), 40% heterozygotes (Asp/Glu) and 49.4% Glu-homozygotes (Glu/Glu). Compared to Asp/Glu and Glu/Glu, Asp/Asp had higher levels of fibrinogen (332 +/- 46 or 329 +/- 33 vs 319 +/- 29 mg/dL, P =.029), white blood cells (6.9 +/- 0.6 or 6.5 +/- 0.3 vs 6.1 +/- 0.9 x 10(3) counts, P =.044), and oxidized low-density lipoprotein cholesterol (68 +/- 21 or 61 +/- 22 vs 59 +/- 20 mg/dL, P =.039), after controlling for several potential confounders. An insignificant association was found between homocysteine (P =.08), C-reactive protein (P =.096), and the distribution of G894T polymorphism (P <.1). No association between the distribution of the polymorphism and hypertension status of the participants was observed. CONCLUSIONS: Our results imply that G894T polymorphism of the endothelial nitric oxide synthase gene is associated with elevated levels of inflammatory and oxidative stress markers, which may partially explain the increased prevalence of G894T polymorphism among patients with cardiovascular disease.

Antoniades C, Tousoulis D, Tountas C, Tentolouris C, Toutouza M, Vasiliadou C, Tsioufis C, Toutouzas P, Stefanadis C. 2004. Vascular endothelium and inflammatory process, in patients with combined Type 2 diabetes mellitus and coronary atherosclerosis: the effects of vitamin C. Diabet Med, 21 (6), pp. 552-558. | Show Abstract | Read more

AIMS: Type 2 diabetes mellitus (DM) and coronary artery disease (CAD) are both associated with endothelial dysfunction and elevated oxidative and inflammatory state. We examined the effect of vitamin C on endothelial function and levels of soluble vascular cell adhesion molecule (sVCAM-1), interleukin-6 (IL-6) and tumour necrosis factor (TNF-alpha), in DM patients with or without CAD and in non-diabetic subjects. METHODS: Thirty-seven patients with DM + CAD, 17 patients with DM without CAD and 21 non-diabetic subjects were divided into groups receiving vitamin C 2 g/day or no anti-oxidant for 4 weeks. Forearm blood flow was determined using venous occlusion gauge-strain plethysmography. Forearm vasodilatory response to reactive hyperemia was considered as index of endothelium-dependent dilation. RESULTS: Baseline levels of IL-6 and TNF-alpha were significantly higher in patients with DM + CAD compared with patients with DM (P < 0.01) or non-diabetic subjects (P < 0.01). IL-6 and TNF-alpha levels were also higher in DM compared with non-diabetic subjects (P < 0.05). sVCAM-1 levels were lower in non-diabetic controls compared with DM + CAD (P < 0.05) or DM (P < 0.05). Reactive hyperaemia was higher in non-diabetic controls compared with DM + CAD (P < 0.001) or DM (P < 0.001). Vitamin C significantly increased reactive hyperaemia only in the DM + CAD group, while it had no effect on serum levels of sVCAM-1, TNF-alpha and IL-6 in any of the groups. CONCLUSIONS: Type 2 diabetes mellitus is associated with impaired endothelial function and increased levels of TNF-alpha, IL-6 and sVCAM-1, especially in patients with DM and CAD. Vitamin C significantly increased forearm vasodilatory response to reactive hyperaemia only in patients with combined DM and CAD.

Parissis JT, Adamopoulos S, Antoniades C, Kostakis G, Rigas A, Kyrzopoulos S, Iliodromitis E, Kremastinos D. 2004. Effects of levosimendan on circulating pro-inflammatory cytokines and soluble apoptosis mediators in patients with decompensated advanced heart failure. Am J Cardiol, 93 (10), pp. 1309-1312. | Show Abstract | Read more

This randomized, placebo-controlled trial showed that levosimendan administration causes a significant reduction of circulating proinflammatory cytokine interleukin-6 and soluble apoptosis mediators, such as soluble Fas and Fas ligand in patients with decompensated heart failure. These immunomodulatory effects may lead to improvement of symptoms and echocardiographic markers of cardiac contractile performance in these patients.

Tentolouris C, Tousoulis D, Antoniades C, Bosinakou E, Kotsopoulou M, Trikas A, Toutouzas P, Stefanadis C. 2004. Endothelial function and proinflammatory cytokines in patients with ischemic heart disease and dilated cardiomyopathy. Int J Cardiol, 94 (2-3), pp. 301-305. | Show Abstract | Read more

BACKGROUND: Proinflammatory cytokines such as tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6) are important mediators of immune response, associated with endothelial dysfunction in patients with coronary artery disease (CAD) or heart failure. We compared endothelial function and levels of IL-6 and TNF-alpha between patients with ischemic heart failure, dilated cardiomyopathy, CAD and healthy controls. METHODS: The population consisted of 20 patients with dilated cardiomyopathy, 48 patients with ischemic cardiomyopathy, 26 patients with CAD and normal left ventricle function and 14 healthy controls. Forearm blood flow was measured using venous occlusion strain gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) or to nitrate were considered as indexes of endothelium-dependent and endothelium-independent dilation, respectively. RESULTS: Levels of IL-6 were significantly higher in ischemic cardiomyopathy compared to CAD patients (P<0.05) or controls (P<0.05) and in patients with dilated cardiomyopathy compared to controls (P<0.05). TNF-alpha levels were significantly higher in both groups with ischemic or dilated cardiomyopathy compared to CAD (P<0.05) or controls (P<0.05). RH% was significantly lower in ischemic and dilated cardiomyopathy compared to CAD (P<0.05) or controls (P<0.001) and higher in dilated than ischemic cardiomyopathy (P<0.05). CONCLUSIONS: Impaired endothelial function and increased inflammatory process were found in both types of heart failure. A greater endothelial dysfunction was observed in patients with ischemic heart failure compared to those with dilated cardiomyopathy, implying that the underlying atherosclerosis may participate in this process.

Antoniades C, Tousoulis D, Tentolouris C, Toutouzas P, Stefanadis C. 2003. Oxidative stress, antioxidant vitamins, and atherosclerosis. From basic research to clinical practice. Herz, 28 (7), pp. 628-638. | Show Abstract | Read more

Oxidative stress is involved in the pathogenesis of atherosclerosis, while a variety of antioxidants has been used in clinical studies, during the past few years, for the prevention and treatment of atherosclerosis. In small clinical studies it was found that both vitamins C and E may improve endothelial function in patients with risk factors for atherosclerosis such as diabetes mellitus, smoking, hypertension, or hypercholesterolemia. However, the initial, hopeful reports regarding the beneficial role of antioxidant vitamins against atherosclerosis, derived from purely observational studies, were followed by the negative results of almost all large randomized trials. Therefore, treatment with antioxidant vitamins C and E should not be recommended for the prevention or treatment of coronary atherosclerosis. New antioxidant strategies are needed to clarify the exact role of antioxidant treatment in coronary atherosclerosis.

Tousoulis D, Antoniades C, Tentolouris C, Tsioufis C, Toutouza M, Toutouzas P, Stefanadis C. 2003. Effects of combined administration of vitamins C and E on reactive hyperemia and inflammatory process in chronic smokers. Atherosclerosis, 170 (2), pp. 261-267. | Show Abstract | Read more

Purpose of this study was to investigate the effect of combined administration of antioxidant vitamins C and E on endothelial function and serum levels of inflammatory markers such as tumor necrosis factor alpha (TNF-alpha), interleukines 1b (IL-1b) and 6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and E-selectin in chronic smokers. Forty-three smokers were randomly divided into four groups receiving vitamin C 2 g/day (group A), vitamin C 2 g/day plus vitamin E 400 IU/day (group B), vitamin C 2 g/day plus vitamin E 800 IU/day (group C) or no antioxidant treatment (group D), for 4 weeks. Forearm blood flow (FBF) was measured using venous occlusion strain gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) was expressed as the percentage change from baseline to post reactive hyperemia blood flow. RH% was significantly increased in groups B (P<0.05) and C (P<0.01), but remained unaffected in groups A and D. Serum levels of IL-1b, IL-6, sVCAM-1 and sICAM-1 were significantly reduced in group C (P<0.05, respectively), but remained unaffected in groups A, B and D. Thus, short term administration of vitamins C (2 g/day) and E (800 IU/day) reduces serum levels of IL-1b, IL-6, sVCAM-1 and sICAM-1, and improves forearm vasodilatory response to reactive hyperemia in healthy young smokers, while monotherapy with vitamin C alone is ineffective.

Tousoulis D, Antoniades C, Tountas C, Bosinakou E, Kotsopoulou M, Toutouzas P, Stefanadis C. 2003. Vitamin C affects thrombosis/ fibrinolysis system and reactive hyperemia in patients with type 2 diabetes and coronary artery disease. Diabetes Care, 26 (10), pp. 2749-2753. | Show Abstract | Read more

OBJECTIVE: To examine the effect of vitamin C on forearm vasodilatory response to reactive hyperemia and on plasma level of plasminogen activator inhibitor 1 (PAI-1), von Willebrand factor (vWF), tissue plasminogen activator (tPA), antithrombin III (ATIII), proteins C and S, and factors V (fV) and VII (fVII) in patients with both type 2 diabetes and CAD. RESEARCH DESIGN AND METHODS: A total of 39 patients with type 2 diabetes and CAD were divided into two groups and received vitamin C (2 g/day) or no antioxidant for 4 weeks. Forearm blood flow was determined using venous occlusion gauge-strain plethysmography at baseline and after treatment. Forearm vasodilatory response to reactive hyperemia (RH%) or nitrate (NTG%) was defined as the percent change of flow from baseline to the maximum flow during reactive hyperemia or after administration of nitrate, respectively. Biochemical markers were determined by enzyme-linked immunosorbent assay (ELISA) or other standard methods. RESULTS: RH% was significantly increased after treatment with vitamin C (from 62.4 +/- 7.2 to 83.1 +/- 9.3%, P = 0.024) but remained unaffected in the control group. Vitamin C decreased plasma levels of fV (from 143 +/- 5.4 to 123 +/- 6.03%, P = 0.038), vWF (from 133.5 +/- 14.5 to 109.5 +/- 11.4%, P = 0.016), and tPA (from 12.3 +/- 0.99 to 8.40 +/- 0.60 ng/ml, P = 0.001), whereas these levels remained unaffected in the control group. The changes in RH%, vWF, and tPA were significantly greater (P = 0.028, 0.036, and 0.007, respectively) in the vitamin C-treated group than in the control group. Levels of ATIII, proteins S and C, fVII, and PAI-1 remained unchanged in all groups. CONCLUSIONS: Short-term treatment with high doses of vitamin C improved RH% and decreased plasma levels of tPA and vWF in patients with type 2 diabetes and CAD.

Antoniades C, Tousoulis D, Tentolouris C, Toutouza M, Marinou K, Goumas G, Tsioufis C, Toutouzas P, Stefanadis C. 2003. Effects of antioxidant vitamins C and E on endothelial function and thrombosis/fibrinolysis system in smokers. Thromb Haemost, 89 (6), pp. 990-995. | Show Abstract

Smoking is associated with endothelial dysfunction and abnormalities in thrombosis/fibrinolysis system, possibly through increased oxidative stress. In this study we investigated the effect of combined antioxidant treatment with vitamins C and E on endothelial function and plasma levels of plasminogen activator inhibitor (PAI-1), von Willebrand factor (vWF), tissue plasminogen activator (tPA) and factor VII (fVII), in smokers. Forty-one healthy smokers were randomly divided into 4 groups receiving vitamin C 2g/day (group A), vitamin C 2g/day plus vitamin E 400 IU/day (group B), vitamin C 2g/day plus vitamin E 800 IU/day (group C) or no antioxidants (controls, group D), for 4 weeks. Forearm blood flow was measured using venous occlusion strain-gauge plethysmography. Forearm vasodilatory response to reactive hyperemia (RH%) or to sublingual nitroglycerin administration (NTG%) were considered as indexes of endothelium dependent or independent dilation respectively. After treatment, RH% was increased only in groups B (p <0.05) and C (p <0.001) but not in groups A and D. Plasma levels of PAI-1 and vWF were decreased only in group C (p <0.05 for both), while PAI-1/tPA ratio was significantly decreased in both groups B and C (p <0.05 for both). NTG% and plasma levels of tPA and fVII remained invariable in all groups. In conclusion, combined administration of vitamin C and vitamin E at high dosages, improved endothelial function and decreased plasma levels of PAI-1, vWF and PAI-1/tPA ratio in chronic smokers.

Antoniades C, Carageorgiou H, Tsakiris S. 2002. Effects of (-)deprenyl (selegiline) on acetylcholinesterase and Na(+),K(+)-ATPase activities in adult rat whole brain. Pharmacol Res, 46 (2), pp. 165-169. | Show Abstract | Read more

(-)Deprenyl is an irreversible inhibitor of monoaminoxidase-B (MAO-B) at concentration 10(-6)M and of both MAO-A and MAO-B at concentration 10(-5)M. In this study, the effect of different concentrations (10(-7)-10(-4)M) of (-)deprenyl on the activity of acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase was investigated in homogenates of adult rat whole brain and in pure enzymes. Drug preincubation period with the homogenates or pure enzymes was 1 and 3h. Brain AChE activity was decreased by 30-39% (P<0.01) when exposed to 10(-4)M (-)deprenyl, by 22-25% (P<0.01) when exposed to 10(-5)M of the drug, and by 18-20% (P<0.01) after preincubation with a concentration of the drug 10(-6)M. Brain Na(+),K(+)-ATPase was stimulated by 46-162% (P<0.001) when the homogenate was preincubated with 10(-4)M (-)deprenyl and by 36-104% (P<0.001) for preincubation with drug concentration 10(-6)M. No effect was observed on the activity of brain Mg(2+)-ATPase, pure AChE or pure Na(+),K(+)-ATPase when exposed to the above concentrations of the drug. We conclude that (-)deprenyl is an indirect AChE inhibitor and Na(+),K(+)-ATPase stimulator in the rat brain (in vitro).

Tousoulis D, Antoniades C, Tentolouris C, Goumas G, Stefanadis C, Toutouzas P. 2002. L-arginine in cardiovascular disease: dream or reality? Vasc Med, 7 (3), pp. 203-211. | Show Abstract | Read more

L-arginine is the substrate for endothelial nitric oxide synthase (eNOS), and the precursor for the synthesis of nitric oxide (NO). This amino acid exerts a number of actions in the cardiovascular system, mainly through the production of NO. However, it also has a number of NO-independent properties, such as the ability to regulate blood and intracellular pH and the effect on the depolarization of endothelial cell membranes. It also has antihypertensive and antioxidant properties, it influences blood viscosity and the coagulation/fibrinolysis system, and it affects the metabolism of glucose, lipids and proteins. L-arginine influences a number of atherosclerosis risk factors such as hypercholesterolemia, hypertension and smoking, improving endothelial function in these patients. However, it does not affect endothelial function in patients with diabetes mellitus. The role of L-arginine in coronary artery disease is still controversial, but it seems that oral or parenteral administration of this amino acid restores endothelial function in the brachial artery and improves coronary microcirculation. The role of L-arginine in heart failure is currently under investigation, and the first results are rather hopeful. In conclusion, L-arginine seems to provide a hopeful prospect for the treatment of cardiovascular diseases. However, more data derived from large-scale prospective studies evaluating the effects of long-term treatment with L-arginine are needed.

Lee R, Bellamkonda K, Jones A, Killough N, Woodgate F, Williams M, Cassimjee I, Handa A, Oxford Abdominal Aortic Aneurysm Study. 2017. Flow Mediated Dilatation and Progression of Abdominal Aortic Aneurysms. Eur J Vasc Endovasc Surg, 53 (6), pp. 820-829. | Show Abstract | Read more

OBJECTIVE/BACKGROUND: Biomarker(s) for prediction of the future progression rate of abdominal aortic aneurysms (AAA) may be useful to stratify the management of individual patients. AAAs are associated with features of systemic inflammation and endothelial dysfunction. Flow mediated dilatation (FMD) of the brachial artery is a recognised non-invasive measurement for endothelial function. We hypothesised that FMD is a potential biomarker of AAA progression and reflects the temporal changes of endothelial function during AAA progression. METHODS: In a prospectively recruited cohort of patients with AAAs (Oxford Abdominal Aortic Aneurysm Study), AAA size was recorded by antero-posterior diameter (APD) (outer to outer) on ultrasound. Annual AAA progression was calculated by (ΔAPD/APD at baseline)/(number of days lapsed/365 days). FMD was assessed at the same time as AAA size measurement. Analyses of data were performed in the overall cohort, and further in subgroups of AAA by size (small: 30-39 mm; moderate: 40-55 mm; large: > 55 mm). RESULTS: FMD is inversely correlated with the diameter of AAAs in all patients (n=162, Spearman's r=-.28, p<.001). FMD is inversely correlated with AAA diameter progression in the future 12 months (Spearman's r=-.35, p=.001), particularly in the moderate size group. Furthermore, FMD deteriorates during the course of AAA surveillance (from a median of 2.0% at baseline to 1.2% at follow-up; p=.004), while surgical repair of AAAs (n=50 [open repair n=22, endovascular repair n=28)] leads to an improvement in FMD (from 1.1% pre-operatively to 3.8% post-operatively; p<.001), irrespective of the type of surgery. CONCLUSION: FMD is inversely correlated with future AAA progression in humans. FMD deteriorates during the natural history of AAA, and is improved by surgery. The utility of FMD as a potential biomarker in the context of AAA warrants further investigation.

Oikonomou EK, Antoniades C. 2017. Immunometabolic regulation of vascular redox state: the role of adipose tissue. Antioxid Redox Signal, | Show Abstract | Read more

SIGNIFICANCE: Vascular oxidative stress plays a crucial role in atherogenesis and cardiovascular disease (CVD). Recent evidence suggests that vascular redox state is under the control of complex pathophysiological mechanisms, ranging from inflammation to obesity and insulin resistance (IR). Recent advances: Adipose tissue (AT) is now recognized as a dynamic endocrine and paracrine organ that secretes several bioactive molecules, called adipokines. AT has recently been shown to regulate vascular redox state in both an endocrine and a paracrine manner through the secretion of adipokines, therefore providing a mechanistic link for the association between obesity, IR, inflammation and vascular disease. Importantly, AT behaves as a sensor of cardiovascular oxidative stress, modifying its secretory profile in response to cardiovascular oxidative injury. CRITICAL ISSUES: The present article presents an up-to-date review of the association between AT and vascular oxidative stress. We focus on the effects of individual adipokines on modulating reactive oxygen species production and scavenging in the vascular wall. In addition, we highlight how inflammation, obesity and IR alter the biology and secretome of AT leading to a more pro-oxidant phenotype with a particular focus on the local regulatory mechanisms of perivascular AT driven by vascular oxidation. FUTURE DIRECTIONS: The complex and dynamic biology of AT as well as its importance in the regulation of vascular redox state provide numerous opportunities for the development of novel, targeted treatments in the management of cardiovascular disease. Therapeutic modulation of AT biology could improve vascular redox state affecting vascular disease pathogenesis.

Antonopoulos AS, Sanna F, Sabharwal N, Thomas S, Oikonomou EK, Herdman L, Margaritis M, Shirodaria C, Kampoli AM, Akoumianakis I et al. 2017. Detecting human coronary inflammation by imaging perivascular fat. Sci Transl Med, 9 (398), | Show Abstract | Read more

Early detection of vascular inflammation would allow deployment of targeted strategies for the prevention or treatment of multiple disease states. Because vascular inflammation is not detectable with commonly used imaging modalities, we hypothesized that phenotypic changes in perivascular adipose tissue (PVAT) induced by vascular inflammation could be quantified using a new computerized tomography (CT) angiography methodology. We show that inflamed human vessels release cytokines that prevent lipid accumulation in PVAT-derived preadipocytes in vitro, ex vivo, and in vivo. We developed a three-dimensional PVAT analysis method and studied CT images of human adipose tissue explants from 453 patients undergoing cardiac surgery, relating the ex vivo images with in vivo CT scan information on the biology of the explants. We developed an imaging metric, the CT fat attenuation index (FAI), that describes adipocyte lipid content and size. The FAI has excellent sensitivity and specificity for detecting tissue inflammation as assessed by tissue uptake of 18F-fluorodeoxyglucose in positron emission tomography. In a validation cohort of 273 subjects, the FAI gradient around human coronary arteries identified early subclinical coronary artery disease in vivo, as well as detected dynamic changes of PVAT in response to variations of vascular inflammation, and inflamed, vulnerable atherosclerotic plaques during acute coronary syndromes. Our study revealed that human vessels exert paracrine effects on the surrounding PVAT, affecting local intracellular lipid accumulation in preadipocytes, which can be monitored using a CT imaging approach. This methodology can be implemented in clinical practice to noninvasively detect plaque instability in the human coronary vasculature.

Margaritis M, Sanna F, Lazaros G, Akoumianakis I, Patel S, Antonopoulos AS, Duke C, Herdman L, Psarros C, Oikonomou EK et al. 2017. Predictive value of telomere length on outcome following acute myocardial infarction: evidence for contrasting effects of vascular vs. blood oxidative stress. Eur Heart J, | Show Abstract | Read more

Aims: Experimental evidence suggests that telomere length (TL) is shortened by oxidative DNA damage, reflecting biological aging. We explore the value of blood (BTL) and vascular TL (VTL) as biomarkers of systemic/vascular oxidative stress in humans and test the clinical predictive value of BTL in acute myocardial infarction (AMI). Methods and results: In a prospective cohort of 290 patients surviving recent AMI, BTL measured on admission was a strong predictor of all-cause [hazard ratio (HR) [95% confidence interval (CI)]: 3.21 [1.46-7.06], P = 0.004] and cardiovascular mortality (HR [95% CI]: 3.96 [1.65-9.53], P = 0.002) 1 year after AMI (for comparisons of short vs. long BTL, as defined by a T/S ratio cut-off of 0.916, calculated using receiver operating characteristic analysis; P adjusted for age and other predictors). To explore the biological meaning of these findings, BTL was quantified in 727 consecutive patients undergoing coronary artery bypass grafting (CABG), and superoxide (O2.-) was measured in peripheral blood mononuclear cells (PBMNC). VTL/vascular O2.- were quantified in saphenous vein (SV) and mammary artery (IMA) segments. Patients were genotyped for functional genetic polymorphisms in P22ph°x (activating NADPH-oxidases) and vascular smooth muscle cells (VSMC) selected by genotype were cultured from vascular tissue. Short BTL was associated with high O2.- in PBMNC (P = 0.04) but not in vessels, whereas VTL was related to O2.- in IMA (ρ = -0.49, P = 0.004) and SV (ρ = -0.52, P = 0.01). Angiotensin II (AngII) incubation of VSMC (30 days), as a means of stimulating NADPH-oxidases, increased O2.- and reduced TL in carriers of the high-responsiveness P22ph°x alleles (P = 0.007). Conclusion: BTL predicts cardiovascular outcomes post-AMI, independently of age, whereas VTL is a tissue-specific (rather than a global) biomarker of vascular oxidative stress. The lack of a strong association between BTL and VTL reveals the importance of systemic vs. vascular factors in determining clinical outcomes after AMI.

Antonopoulos AS, Antoniades C. 2017. The role of epicardial adipose tissue in cardiac biology: classic concepts and emerging roles. J Physiol, 595 (12), pp. 3907-3917. | Show Abstract | Read more

Classic concepts about the role of epicardial adipose tissue (EpAT) in heart physiology include its role in cardiac metabolism, mechanical protection of coronaries, innervation and possibly cryoprotection of the heart too. Nevertheless, recent evidence has revealed that epicardial adipose tissue regulates multiple aspects of cardiac biology including myocardial redox state, intracellular Ca(2+) cycling, the electrophysiological and contractile properties of cardiomyocytes, cardiac fibrosis as well as coronary atherosclerosis progression. Moreover, it is now understood that the communication between EpAT and the heart is regulated by complex bidirectional pathways, since not only do adipokines regulate cardiac function, but also the heart affects EpAT biology via paracrine 'reverse' signalling. Such complex interactions as well as epicardial fat accumulation as a consequence of cardiac disease and epicardium to adipocyte differentiation should be taken into account by the clinical studies investigating EpAT as a risk marker and its potential as a therapeutic target against cardiovascular disease. Further in-depth exploration of the molecular mechanisms regulating the cross-talk between the heart and EpAT is expected to enhance our understanding regarding the role of the latter in cardiac physiology and relevant disease mechanisms.

Antonopoulos AS, Margaritis M, Verheule S, Recalde A, Sanna F, Herdman L, Psarros C, Nasrallah H, Coutinho P, Akoumianakis I et al. 2016. Mutual Regulation of Epicardial Adipose Tissue and Myocardial Redox State by PPAR-γ/Adiponectin Signalling. Circ Res, 118 (5), pp. 842-855. | Show Abstract | Read more

RATIONALE: Adiponectin has anti-inflammatory effects in experimental models, but its role in the regulation of myocardial redox state in humans is unknown. Although adiponectin is released from epicardial adipose tissue (EpAT), it is unclear whether it exerts any paracrine effects on the human myocardium. OBJECTIVE: To explore the cross talk between EpAT-derived adiponectin and myocardial redox state in the human heart. METHODS AND RESULTS: EpAT and atrial myocardium were obtained from 306 patients undergoing coronary artery bypass grafting. Functional genetic polymorphisms that increase ADIPOQ expression (encoding adiponectin) led to reduced myocardial nicotinamide adenine dinucleotide phosphate oxidase-derived O2 (-), whereas circulating adiponectin and ADIPOQ expression in EpAT were associated with elevated myocardial O2 (-). In human atrial tissue, we demonstrated that adiponectin suppresses myocardial nicotinamide adenine dinucleotide phosphate oxidase activity, by preventing AMP kinase-mediated translocation of Rac1 and p47(phox) from the cytosol to the membranes. Induction of O2 (-) production in H9C2 cardiac myocytes led to the release of a transferable factor able to induce peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ expression in cocultured EpAT. Using a NOX2 transgenic mouse and a pig model of rapid atrial pacing, we found that oxidation products (such as 4-hydroxynonenal) released from the heart trigger peroxisome proliferator-activated receptor-γ-mediated upregulation of ADIPOQ in EpAT. CONCLUSIONS: We demonstrate for the first time in humans that adiponectin directly decreases myocardial nicotinamide adenine dinucleotide phosphate oxidase activity via endocrine or paracrine effects. Adiponectin expression in EpAT is controlled by paracrine effects of oxidation products released from the heart. These effects constitute a novel defense mechanism of the heart against myocardial oxidative stress.

Fabritz L, Guasch E, Antoniades C, Bardinet I, Benninger G, Betts TR, Brand E, Breithardt G, Bucklar-Suchankova G, Camm AJ et al. 2016. Expert consensus document: Defining the major health modifiers causing atrial fibrillation: a roadmap to underpin personalized prevention and treatment. Nat Rev Cardiol, 13 (4), pp. 230-237. | Show Abstract | Read more

Despite remarkable advances in antiarrhythmic drugs, ablation procedures, and stroke-prevention strategies, atrial fibrillation (AF) remains an important cause of death and disability in middle-aged and elderly individuals. Unstructured management of patients with AF sharply contrasts with our detailed, although incomplete, knowledge of the mechanisms that cause AF and its complications. Altered calcium homeostasis, atrial fibrosis and ageing, ion-channel dysfunction, autonomic imbalance, fat-cell infiltration, and oxidative stress, in addition to a susceptible genetic background, contribute to the promotion, maintenance, and progression of AF. However, clinical management of patients with AF is currently guided by stroke risk parameters, AF pattern, and symptoms. In response to this apparent disconnect between the known pathophysiology of AF and clinical management, we propose a roadmap to develop a set of clinical markers that reflect the major causes of AF in patients. Thereby, the insights into the mechanisms causing AF will be transformed into a format that can underpin future personalized strategies to prevent and treat AF, ultimately informing better patient care.

Antonopoulos AS, Margaritis M, Coutinho P, Shirodaria C, Psarros C, Herdman L, Sanna F, De Silva R, Petrou M, Sayeed R et al. 2015. Adiponectin as a link between type 2 diabetes and vascular NADPH oxidase activity in the human arterial wall: the regulatory role of perivascular adipose tissue. Diabetes, 64 (6), pp. 2207-2219. | Show Abstract | Read more

Oxidative stress plays a critical role in the vascular complications of type 2 diabetes. We examined the effect of type 2 diabetes on NADPH oxidase in human vessels and explored the mechanisms of this interaction. Segments of internal mammary arteries (IMAs) with their perivascular adipose tissue (PVAT) and thoracic adipose tissue were obtained from 386 patients undergoing coronary bypass surgery (127 with type 2 diabetes). Type 2 diabetes was strongly correlated with hypoadiponectinemia and increased vascular NADPH oxidase-derived superoxide anions (O2˙(-)). The genetic variability of the ADIPOQ gene and circulating adiponectin (but not interleukin-6) were independent predictors of NADPH oxidase-derived O2˙(-). However, adiponectin expression in PVAT was positively correlated with vascular NADPH oxidase-derived O2˙(-). Recombinant adiponectin directly inhibited NADPH oxidase in human arteries ex vivo by preventing the activation/membrane translocation of Rac1 and downregulating p22(phox) through a phosphoinositide 3-kinase/Akt-mediated mechanism. In ex vivo coincubation models of IMA/PVAT, the activation of arterial NADPH oxidase triggered a peroxisome proliferator-activated receptor-γ-mediated upregulation of the adiponectin gene in the neighboring PVAT via the release of vascular oxidation products. We demonstrate for the first time in humans that reduced adiponectin levels in individuals with type 2 diabetes stimulates vascular NADPH oxidase, while PVAT "senses" the increased NADPH oxidase activity in the underlying vessel and responds by upregulating adiponectin gene expression. This PVAT-vessel interaction is identified as a novel therapeutic target for the prevention of vascular complications of type 2 diabetes.

Antonopoulos AS, Margaritis M, Coutinho P, Digby J, Patel R, Psarros C, Ntusi N, Karamitsos TD, Lee R, De Silva R et al. 2014. Reciprocal effects of systemic inflammation and brain natriuretic peptide on adiponectin biosynthesis in adipose tissue of patients with ischemic heart disease. Arterioscler Thromb Vasc Biol, 34 (9), pp. 2151-2159. | Show Abstract | Read more

OBJECTIVE: To explore the role of systemic inflammation in the regulation of adiponectin levels in patients with ischemic heart disease. APPROACH AND RESULTS: In a cross-sectional study of 575 subjects, serum adiponectin was compared between healthy subjects, patients with coronary artery disease with no/mild/severe heart failure (HF), and patients with nonischemic HF. Adiponectin expression and release from femoral, subcutaneous and thoracic adipose tissue was determined in 258 additional patients with coronary artery bypass grafting. Responsiveness of the various human adipose tissue depots to interleukin-6, tumor necrosis factor-α, and brain natriuretic peptide (BNP) was examined by using ex vivo models of human fat. The effects of inducible low-grade inflammation were tested by using the model of Salmonella typhi vaccine-induced inflammation in healthy individuals. In the cross-sectional study, HF strikingly increased adiponectin levels. Plasma BNP was the strongest predictor of circulating adiponectin and its release from all adipose tissue depots in patients with coronary artery bypass grafting, even in the absence of HF. Femoral AT was the depot with the least macrophages infiltration and the largest adipocyte cell size and the only responsive to systemic and ex vivo proinflammatory stimulation (effect reversible by BNP). Low-grade inflammation reduced circulating adiponectin levels, while circulating BNP remained unchanged. CONCLUSIONS: This study demonstrates the regional variability in the responsiveness of human adipose tissue to systemic inflammation and suggests that BNP (not systemic inflammation) is the main driver of circulating adiponectin in patients with advanced atherosclerosis even in the absence of HF. Any interpretation of circulating adiponectin as a biomarker should take into account the underlying disease state, background inflammation, and BNP levels.

Margaritis M, Channon KM, Antoniades C. 2014. Statins as regulators of redox state in the vascular endothelium: beyond lipid lowering. Antioxid Redox Signal, 20 (8), pp. 1198-1215. | Show Abstract | Read more

SIGNIFICANCE: Endothelial dysfunction and the imbalance between nitric oxide (NO) and reactive oxygen species production in the vascular endothelium are important early steps in atherogenesis, a major socioeconomic health problem. Statins have well-established roles in primary and secondary prevention of cardiovascular disease (CVD), due to both their lipid-lowering capacity and their pleiotropic properties. It is therefore important to understand the mechanisms by which statins can modify endothelial function and affect atherogenesis. RECENT ADVANCES: In the last decade, the concept of statin pleiotropy has been reinforced by a large number of cell culture, animal, and translational studies. Statins have been shown to suppress the activity of pro-oxidant enzymes (such as NADPH oxidase) and pro-inflammatory transcriptional pathways in the endothelium. At the same time, they enhance endothelial NO synthase expression and activity while they also improve its enzymatic coupling. This leads to increased NO bioavailability and improved endothelial function. CRITICAL ISSUES: Despite significant recent advances, the exact mechanisms of statin pleitropy are still only partially understood. The vast majority of the published literature relies on animal studies, while the actual mechanistic studies in humans are limited. FUTURE DIRECTIONS: The success of statins as endothelium redox-modifying agents with a direct impact on clinical outcome highlights the importance of the endothelium as a therapeutic target in CVD. Better understanding of the mechanisms that underlie endothelial dysfunction could lead to the design of novel therapeutic strategies that target the vascular endothelium for the prevention and treatment of CVD.

Margaritis M, Antonopoulos AS, Digby J, Lee R, Reilly S, Coutinho P, Shirodaria C, Sayeed R, Petrou M, De Silva R et al. 2013. Interactions between vascular wall and perivascular adipose tissue reveal novel roles for adiponectin in the regulation of endothelial nitric oxide synthase function in human vessels. Circulation, 127 (22), pp. 2209-2221. | Show Abstract | Read more

BACKGROUND: Adiponectin is an adipokine with potentially important roles in human cardiovascular disease states. We studied the role of adiponectin in the cross-talk between adipose tissue and vascular redox state in patients with atherosclerosis. METHODS AND RESULTS: The study included 677 patients undergoing coronary artery bypass graft surgery. Endothelial function was evaluated by flow-mediated dilation of the brachial artery in vivo and by vasomotor studies in saphenous vein segments ex vivo. Vascular superoxide (O2(-)) and endothelial nitric oxide synthase (eNOS) uncoupling were quantified in saphenous vein and internal mammary artery segments. Local adiponectin gene expression and ex vivo release were quantified in perivascular (saphenous vein and internal mammary artery) subcutaneous and mesothoracic adipose tissue from 248 patients. Circulating adiponectin was independently associated with nitric oxide bioavailability and O2(-) production/eNOS uncoupling in both arteries and veins. These findings were supported by a similar association between functional polymorphisms in the adiponectin gene and vascular redox state. In contrast, local adiponectin gene expression/release in perivascular adipose tissue was positively correlated with O2(-) and eNOS uncoupling in the underlying vessels. In ex vivo experiments with human saphenous veins and internal mammary arteries, adiponectin induced Akt-mediated eNOS phosphorylation and increased tetrahydrobiopterin bioavailability, improving eNOS coupling. In ex vivo experiments with human saphenous veins/internal mammary arteries and adipose tissue, we demonstrated that peroxidation products produced in the vascular wall (ie, 4-hydroxynonenal) upregulate adiponectin gene expression in perivascular adipose tissue via a peroxisome proliferator-activated receptor-γ-dependent mechanism. CONCLUSIONS: We demonstrate for the first time that adiponectin improves the redox state in human vessels by restoring eNOS coupling, and we identify a novel role of vascular oxidative stress in the regulation of adiponectin expression in human perivascular adipose tissue.

Antoniades C, Demosthenous M, Reilly S, Margaritis M, Zhang MH, Antonopoulos A, Marinou K, Nahar K, Jayaram R, Tousoulis D et al. 2012. Myocardial redox state predicts in-hospital clinical outcome after cardiac surgery effects of short-term pre-operative statin treatment. J Am Coll Cardiol, 59 (1), pp. 60-70. | Show Abstract | Read more

OBJECTIVES: The purpose of this study was to evaluate the role of the myocardial redox state in the development of in-hospital complications after cardiac surgery and the effect of statins on the myocardial redox state. BACKGROUND: Statins improve clinical outcome after cardiac surgery, but it is unclear whether they exert their effects by modifying the myocardial redox state. METHODS: We quantified myocardial superoxide anion (O(2)(-)) and peroxynitrite (ONOO(-)) and their enzymatic sources in samples of the right atrial appendage (RAA) from 303 patients undergoing cardiac surgery who were followed up until discharge, and in 42 patients who were randomized to receive 3-day treatment with atorvastatin 40 mg/d or placebo before surgery. The mechanisms by which atorvastatin modifies myocardial redox state were investigated in 26 RAA samples that were exposed to atorvastatin ex vivo. RESULTS: Atrial O(2)(-) (derived mainly from nicotinamide adenine dinucleotide phosphate [NADPH] oxidases) and ONOO(-) were independently associated with increased risk of atrial fibrillation, the need for post-operative inotropic support, and the length of hospital stay. Pre-operative atorvastatin treatment suppressed atrial NADPH oxidase activity and myocardial O(2)(-) and ONOO(-) production. Ex vivo incubation of RAA samples with atorvastatin induced a mevalonate-reversible and Rac1-mediated inhibition of NADPH oxidase. CONCLUSIONS: There is a strong independent association between myocardial O(2)(-)/ONOO(-) and in-hospital complications after cardiac surgery. Both myocardial O(2)(-) and ONOO(-) are reduced by pre-operative statin treatment, through a Rac1-mediated suppression of NADPH oxidase activity. These findings suggest that inhibition of myocardial NADPH oxidases may contribute to the beneficial effect of statins in patients undergoing cardiac surgery. (Effects of Atorvastatin on Endothelial Function, Vascular and Myocardial Redox State in High Cardiovascular Risk Patients; NCT01013103).

Margaritis M, Channon KM, Antoniades C. 2012. Statins and vein graft failure in coronary bypass surgery Current Opinion in Pharmacology, 12 (2), pp. 172-180. | Show Abstract | Read more

Saphenous vein grafts used in coronary artery bypass graft surgery suffer from lower patency rates compared to left internal mammary artery. A number of clinical trials and observational studies have demonstrated a significant benefit of statin treatment on vein graft patency. Aside from their well-known lipid-lowering capacities, statins exert pleiotropic effects by direct inhibition of the mevalonate pathway in the wall of these grafts. This leads to reduced geranylgeranylation of small GTPases such as Rho and Rac. Through this LDL-independent mechanism, statins improve endothelial function and reduce vascular inflammation and oxidative stress, inhibiting also smooth muscle cell proliferation and migration. Although the existing evidence supports a beneficial effect of statins on vein grafts biology, more clinical trials focused on the effect of aggressive statin treatment on vein graft patency are required, in order to safely translate this strategy into clinical practice. © 2012 Elsevier Ltd.

Antoniades C, Cunnington C, Antonopoulos A, Neville M, Margaritis M, Demosthenous M, Bendall J, Hale A, Cerrato R, Tousoulis D et al. 2011. Induction of vascular GTP-cyclohydrolase I and endogenous tetrahydrobiopterin synthesis protect against inflammation-induced endothelial dysfunction in human atherosclerosis. Circulation, 124 (17), pp. 1860-1870. | Show Abstract | Read more

BACKGROUND: The endothelial nitric oxide synthase cofactor tetrahydrobiopterin (BH4) is essential for maintenance of enzymatic function. We hypothesized that induction of BH4 synthesis might be an endothelial defense mechanism against inflammation in vascular disease states. METHODS AND RESULTS: In Study 1, 20 healthy individuals were randomized to receive Salmonella typhi vaccine (a model of acute inflammation) or placebo in a double-blind study. Vaccination increased circulating BH4 and interleukin 6 and induced endothelial dysfunction (as evaluated by brachial artery flow-mediated dilation) after 8 hours. In Study 2, a functional haplotype (X haplotype) in the GCH1 gene, encoding GTP-cyclohydrolase I, the rate-limiting enzyme in biopterin biosynthesis, was associated with endothelial dysfunction in the presence of high-sensitivity C-reactive protein in 440 coronary artery disease patients. In Study 3, 10 patients with coronary artery disease homozygotes for the GCH1 X haplotype (XX) and 40 without the haplotype (OO) underwent S Typhi vaccination. XX patients were unable to increase plasma BH4 and had a greater reduction of flow-mediated dilation than OO patients. In Study 4, vessel segments from 19 patients undergoing coronary bypass surgery were incubated with or without cytokines (interleukin-6/tumor necrosis factor-α/lipopolysaccharide) for 24 hours. Cytokine stimulation upregulated GCH1 expression, increased vascular BH4, and improved vasorelaxation in response to acetylcholine, which was inhibited by the GTP-cyclohydrolase inhibitor 2,4-diamino-6-hydroxypyrimidine. CONCLUSIONS: The ability to increase vascular GCH1 expression and BH4 synthesis in response to inflammation preserves endothelial function in inflammatory states. These novel findings identify BH4 as a vascular defense mechanism against inflammation-induced endothelial dysfunction.

Development of novel, imaging tools for the early detection of vascular inflammation using computerised tomography

This project will build on an ongoing translational programme of work that led to the discovery of new communication links between the vascular wall and its surrounding perivascular fat. By using a novel, recently patented technology studying these interactions, the project will explore the ability of non-invasive imaging by computerised tomography to provide functional in addition to structural information on the degree of vascular inflammation and atherosclerotic plaque composition in the ...

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Exploring the role of vascular redox signalling in human atherosclerosis progression

This is a project examining the molecular mechanisms of atherosclerosis progression in humans. The study will rely on the Oxford CABG Bioresource (OCB) cohort, which includes a bioresource of human vascular and myocardial tissue from ~900 patients who underwent cardiac surgery, with simultaneous extensive molecular, structural and functional phenotyping of their arterial tree. The project will include prospective advanced vascular imaging using computerised tomography angiography as means of ...

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