Renal subcapsular islet transplantation in the rat: a comparison of three techniques

The purpose of this study was to investigate whether the results of renal subcapsular islet transplantation in the rat could be improved by placing the islets in a blood or plasma clot. Islets were isolated and transplanted into diabetic recipients using a standardized technique and islet function post transplantation measured by the ability to restore normoglycemia and by intravenous glucose tolerance testing. It was found that 750 islets in minimal essential medium reversed diabetes (6/6 recipients) and produced a normal IVGTT whereas the success rate if the islets were placed in a blood or plasma clot was only 0/6 and 1/6 recipients respectively (p less than 0.008). We conclude that any possible benefit from trophic factors within blood or plasma is outweighed by the fact that islets in a blood or plasma clot are distanced from the blood supply on the kidney surface. This finding has important implications for human islet transplantation.