Humanized mouse models for type 1 diabetes including pancreatic islet transplantation.

We comment here on the suitability of available mouse models for type 1 diabetes research including research on therapeutic pancreatic islet transplantation. The major emphasis will be laid on models that require minimal invasive procedures. Most biological processes are too complex for a complete recapitulation in a test tube. The study of innate or even adaptive immune responses involves a number of different cell types and organs making in vitro studies unreliable but also providing extreme challenges for the use of surrogate model organisms. Studying these processes directly in humans is impossible due to ethical and technical constraints. To resolve this problem small animal models such as mice or rats are frequently used to study mechanisms of complex diseases. This has brought much insight into hematopoiesis and immune cell function including type 1 diabetes (T1D); however, 65 million years of evolution introduced striking differences between mice and humans 1. In fact, none of the many suggested therapies arising from studies using mice 2 3 that have promised prevention or even reversion of T1D made it into the clinic yet 4 5 6. The reason for this are major species-specific differences between rodents and humans regarding the immune system and beta cells.