Oxygen tension in isolated transplanted rat islets and in islets of rat whole-pancreas transplants.

Despite similar immunosuppressive protocols having been applied, the success rate of pancreatic islet transplantation has been much lower than that of whole-pancreas transplantation. We compared the oxygen tension in syngeneically transplanted isolated rat islets and islets of syngeneic rat whole-pancreatic grafts, with native islets, using Clark-type microelectrodes. An oxygen tension of approximately 40 mmHg was recorded in both native islets and in islets of the whole-pancreas graft. Isolated islets transplanted under the renal capsule had a markedly lower oxygen tension ( approximately 6 mmHg). The exocrine parenchyma of the native and of the transplanted pancreatic gland had an oxygen tension of approximately 30 mmHg. The lower oxygen tension in transplanted isolated islets may be one explanation for the more frequent failures of transplanted islets compared with the outcome when the whole pancreatic gland is transplanted.