Is the intraportal or renal subcapsular space a preferable site for islet allo- and xeno-transplantation? A brief historical review

Diabetes mellitus and end-stage renal disease (ESRD) are major causes of morbidity and mortality worldwide.Pancreatic islet transplantation offers potential insulin independence. Different sites and their suitability for islet transplantation have been investigated, including renal subcapsular and intraportal sites, among others. Various limitations and complications have been reported, such as the number of donor islet species, islet isolation, and site of transplantation. Combining islets and kidney transplantation in diabetic patients suffering from ESRD has several advantages.This review compares the experimental experience of the renal subcapsular and intraportal sites for islet allo- and xeno-transplantation. The subcapsular site appears preferable in rodent models. The intraportal site has been more successful in large animals. Combined islet-kidneys have been suggested as a treatment targeting both ESRD and type 1 diabetes. With our increasing ability to genetically-engineer pigs, and the availability of novel immunosuppressive agents, xenotransplantation is an emerging therapeutic option.