COMPARISON OF 2 METHODS OF PANCREAS ISLETS IMMUNOISOLATION

The efficacy of two methods of Langerhans islets immunoisolation was c ompared. For this purpose the function of islets encapsulated with alg inate/polyethylenimine/protamine/heparin (APPH) or with alginate/poly- L-lisine/alginate (APA) membranes was assessed: in vitro according to their survival and response to glucose challenges, and in vivo accordi ng to their capability to provide sufficient insulin delivery to maint ain normal fasting blood glucose following xenotransplantation to stre ptozotocin diabetic mice. In vitro insulin secretion and the response to glucose challenge of APPH and APA encapsulated islets were comparab le to free islets. In vivo intraperitoneal concordant xenotransplantat ion of APA encapsulated rat islets reversed the diabetic state of stre ptozotocin diabetic mice for a longer period, than APPH islet grafts. This study clearly demonstrated the inadequacy of in vitro methods in the prediction of in vivo results of islets transplantation.