History and future prospects of islet transplantation in Japan

Abstract

Islet transplantation for type 1 diabetes is a minimally invasive cell therapy. It was first introduced to the world in 1974, but the results were poor. The Edmonton protocol in 2000 and the subsequent CIT protocol significantly improved the outcome. In Japan as well, clinical application has been promoted since 1997 by the Japan Pancreas and Islet Transplant Association (JPITA). Initially, as in the rest of the world, the long-term survival rate of islets was low using the Edmonton protocol. Thereafter, the results were significantly improved using the CIT protocol. Finally, islet transplantation was covered by insurance in 2020 in Japan. Future issues include the indications for pancreas transplantation and islet transplantation in patients with type 1 diabetes, the distribution of donor pancreases to pancreas transplantation, islet transplantation, and medical costs. Islet transplantation is expected to develop into xenotransplantation and iPS cell transplantation in the future.