Human islet autotransplantation: the trail thus far and the highway ahead

Human islet transplantation is one of the three treatment modalities besides the daily administration of exogenous insulin and pancreas transplantation, which can be applied for the treatment of type 1 diabetic patients. Although the metabolic control achieved after islet transplantation is superior compared to exogenous insulin administration, many hurdles remain to be overcome before islet transplantation can be called a routine therapy for type 1 diabetic patients. In contrast to many other therapeutic approaches, proof of principle has been obtained for islet transplantation: As demonstrated in islet autotransplantation, the transplanted islets are not only able to survive in another organ, namely the liver, but also able to retain their functional role, in some patients even for decades. The main challenge for islet allotransplantation is, therefore, to imitate this success, thereby providing type 1 diabetic patients with a cellular therapy lasting for decades and thus circumventing the daily injections of insulin.