[Islet transplantation in type I diabetes mellitus].

Type 1 diabetes mellitus results from autoimmune destruction of the insulin-secreting cells in the pancreas. The dramatic breakthrough in 2000 with the "Edmonton protocol" for successful solitary islet transplantation has restored optimism for the application of islet transplantation as a treatment for type I diabetes. Due to the recent successes, islet transplantation has evolved from a theoretical concept to its current status as a therapeutic option for patients with type 1 diabetes. Islet transplantation has shown to normalize metabolic control in a way that has been virtually impossible to achieve with exogenous insulin. The less invasive procedure of islet transplantation as compared to whole pancreas transplantation in patients with type 1 diabetes mellitus would be expected to be safer and much less costly. However, this procedure also requires lifetime immunosuppression with drugs. The limited availability of donor organs and the necessity of transplantation of several pancreata in order to achieve insulin independence limit this procedure to a small minority of patients. Unlike the North American centers, the European centers concentrated their efforts on islet after kidney and simultaneous islet kidney transplantation. The two Swiss islet transplantation programs have been pioneers in applying the steroid-free "Edmonton protocol" to simultaneous islet-kidney and islet after kidney transplantation. The long term follow-up showed that islet function decreases over time. In order to maintain insulin independence repeated islet transplants would have to be given to the patients. Therefore, there has been a change in paradigm over time. The major goal of islet transplantation focuses now on achieving a good blood glucose control and avoidance of severe hypoglycaemic episodes rather than only insulin-independence. Thus, due to the limited supply of donor organs, more patients can benefit from islet transplantation. Small insulin doses of exogenous insulin prevent stress on the islet in particular after meals and might help to maintain the transplanted islet mass over time. Due to the severe limitations of immunosuppression solitary islet transplantation is limited to a very small number of patients with type 1 diabetes. The most common indication for islet transplantation in Switzerland is terminal kidney failure in patients with type I diabetes. A simultaneous islet-kidney or pancreas-kidney transplantation should be offered to these patients. The choice between islet or pancreas transplantation is a matter of age and diabetic complications because the perioperative risk is considerably higher in pancreas transplantation.