Update on islet cell transplantation for type 1 diabetes.

Despite modern medical breakthroughs, diabetes mellitus is a worldwide leading cause of morbidity and mortality. Definitive surgical treatment of diabetes mellitus was established with the advent and refinement of clinical pancreas transplantation in the 1960s. During the following decades, critical discoveries involving islet isolation and engraftment took place. Clinical islet cell transplantation represents the potential for reduced insulin requirements and debilitating hypoglycemic episodes without the morbidity of surgery. Unfortunately, islet cell transplantation was unable to achieve comparable results with solid organ transplantation. This was until the Edmonton protocol (steroid-free immunosuppression) was described, which demonstrated that islet cell transplantation could be a viable alternative to pancreas transplantation. Significant advances in islet purification techniques and novel immunomodulatory agents have since renewed interest in islet cell transplantation. Yet the field is still challenged by a limited supply of islet cells, inadequate engraftment, and the deleterious effects of chronic immunosuppression. This article discusses the history and the current status of clinical islet cell transplantation.