Pancreatic islet transplantation. Experimental and clinical aspects.

The deteriorating complications of diabetes mellitus (i.e. nephropathy, neuropathy, and retinopathy) have encouraged several attempts of causal therapy apart from a diversity of insulin therapies. These attempts include whole organ or segmental pancreas transplantation. In recent years, increasing interest has been shown in transplantation of isolated islets either directly, introduced intraportally, intramuscularly, inter alia, or encapsulated in artificial devices providing an immuno-isolation. Clinical application has revealed promising results concerning the immunological aspects. However, quantitative assessment points to a difficulty in achieving satisfactory amounts of islets to attain normoglycaemia. Work with fetal pancreata has shown these to possess a growth potential in vitro thus, possibly, aiding the quantification of islets in transplantation models. In the field of pancreatic islet transplantation, future models include microencapsulation and hybrid artificial devices, both of which provide immuno-isolation - thus the ability of allo- as well as xeno-transplantation. The obvious advantage of immuno-isolated islet transplant, as opposed to segmentally engrafted pancreas, is stressed by the fact of the latter being a possible target for recurrent diabetes.