From stem cells to beta cells: new strategies in cell therapy of diabetes mellitus

Islet transplantation as a potential treatment for diabetes has been invest igated extensively over the past 10 years. Such an approach, however, will always be limited mainly because it is difficult to obtain sufficiently lar ge numbers of purified islets from cadaveric donors. One alternative to org an or tissue transplantation is to use a renewable source of cells. Stem ce lls are clonogenic cells capable of both self-renewal and multilineage diff erentiation. These cells have the potential to proliferate and differentiat e into any type of cell and to be genetically modified in vitro, thus provi ding cells which can be isolated and used for transplantation. Recent studi es have given well-defined differentiation protocols, which can be used to guide stem cells into specific cell lineages as neurons, cardiomyocytes and insulin-secreting cells. Moreover, these derived cells have been useful in different animal models. In this regard. insulin-secreting cells derived f rom R1 mouse embryonic stem cells restore blood glucose concentrations to n ormal when they are transplanted into streptozotocin-induced diabetic anima ls. These results show that diabetes could be among the first applications of stem cell therapy.