Successes and Disappointments with Clinical Islet Transplantation

Abstract

Islet transplantation is considered a therapeutic option for patients with type 1 diabetes who have life-threatening hypoglycemic episodes. After the procedure, the frequency and severity of hypoglycemic episodes generally decrease and the majority of patients have sustained graft function as indicated by detectable levels of C-peptide. However, true insulin independence is seldom achieved and gener- ally not long-lasting. Apart from the low insulin-independence rates, reasons for concern regarding this procedure are the side effects of the immunosuppressive therapy, alloimmunization, and the high costs. Moreover, whether islet transplan- tation prevents the progression of diabetic micro- and macrovascular complica- tions more effectively than standard insulin therapy is largely unknown. Areas of current research include the development of less toxic immunosuppressive regi- mens, the control of the inflammatory reaction immediately after transplantation, the identification of the optimal anatomical site for islet infusion, and the possi- bility to encapsulate transplanted islets to protect them from the alloimmune response. Nowadays, islet transplantation is still an experimental procedure, which is only indicated for a highly selected group of type 1 diabetic patients with life-threatening hypoglycemic episodes.\r