[Cell therapy for diabetes mellitus: beyond stem cells]

Type 1 diabetes is an autoimmune disease of unknown etiology characterized by destruction of pancreatic beta cells, leading to absolute insulin deficiency. Standard therapy includes the use of exogenous insulin. However, due to the difficulty to achieve a tight metabolic control, a number of patients will present severe complications, including vascular, renal and ophthalmologic disease. On the other hand, a more strict metabolic control is often associated with episodes of life threatening hypoglycemia. This motivated the research and development of new alternative treatments, such as the transplantation of insulin producing beta cells, obtained from cadaveric pancreatic islets. Best results with this therapy were observed with consecutive islet injection from more than one donor and immunosuppressive therapy without steroids. However, the scarcity of organs as well as an increased immune reaction derived from the use of pancreas from different donors have limited this therapy to markedly selected patients and highly experienced centers. Furthermore, lifelong administration of immunosuppressive drugs may produce undesired secondary effects. Regenerative medicine opens the possibility of using stem cells capable of differentiating into insulin-producing cells after stimulation by diverse trophic factors that may act over stem cells located within a specific tissue.