Clinical islet transplantation: recent advances in the field

Islet transplantation has emerged as a novel and promising surgical strategy for the treatment of type 1 diabetes mellitus. Almost a decade after the introduction of steroid-free immunosuppression, we have observed steady improvement in the success rate of islet transplantation for the treatment of patients with hypoglycemic unawareness and glycemic lability. However, cell-based therapies face several barriers for widespread success. These barriers include: limited donor pool, innate immune driven inflammation after infusion, acute and chronic immune rejection, and a lack of reliable markers for metabolic follow-up. Recent analysis of data from large multicenter databases suggests that refinements in technical aspects of islet isolation, culture, and immunosuppressive management of the recipient have caused a major and marked improvement observed in recent years in insulin independence rates and metabolic control of the disease. In this review, we highlight the most recent findings published in the literature and focus on important advances in immunosuppression, in vitro beta cell expansion, islet graft assessment, and islet encapsulation, and discuss potential future directions in the field of clinical islet transplantation.