EFFICACY OF A PREVASCULARIZED EXPANDED POLYTETRAFLUOROETHYLENE SOLID SUPPORT SYSTEM AS A TRANSPLANTATION SITE FOR PANCREATIC-ISLETS

An intraperitoneally located and prevascularized expanded polytetraflu oroethylene solid support is potentially a suitable transplantation si te for encapsulated pancreatic islets, because it allows for both the implantation of a large volume islet graft in the immediate vicinity o f blood vessels, and its complete removal. The present study investiga tes the efficacy of such solid supports for the implantation of nonenc apsulated islet isografts in streptozotocin diabetic rat recipients, T hese solid supports were always coated with acidic fibroblast growth f actor, because we found that this growth factor enhances the neovascul arization, The success rates of 5-mu l (group A) and 10-mu l (group B) islet isografts in solid supports were compared with the success rate s of 5-mu l (group C) and 10-mu l (group D) islet isografts implanted in the unmodified peritoneal cavity. Four of seven rats in group A and all seven rats in group B became normoglycemic for at least 6 months. Only two of eight rats in group C and four of eleven rats in group D showed normoglycemia. The normoglycemia lasted for at least 6 months i n zero of two animals in group C and in three of four animals in group D. Because of the low success rates in groups C and D, intravenous an d oral glucose testing were restricted to the successful recipients in groups A and B, Glucose tolerance was found to be proportional to the grafted islet volume but, expectedly, in both groups the glucose tole rance and the insulin responses were somewhat lower than in controls, Thus, the prevascularized expanded polytetrafluoroethylene solid suppo rt, rather than the unmodified peritoneal cavity, is an efficacious tr ansplantation site, potentially suitable for encapsulated islets.