Cyclosporine does not inhibit the process of revascularization of pancreatic islet transplantation.

The immunosuppressive drug cyclosporin-A (CsA) has been widely used to prevent pancreatic islet allograft rejection. Because it has been suggested that CsA may inhibit the process of revascularization of transplanted islets, the purpose of the study was to analyze by a double indirect immunofluorescence technique the revascularization process of isolated islets grafted in the liver and in the renal subcapsular space of rats treated with immunosuppressive doses of CsA. Lewis rats were grafted with either Lewis (isografts) or Wistar (allografts) pancreatic islets obtained by collagenase digestion. Rats were killed at different days after implantation and the liver and kidney bearing the grafted islets were snap frozen and immunohistochemically stained with a double immunofluorescence technique using a rabbit antifactor-VIII antiserum (which labels endothelial cells) and a guinea pig antiinsulin antibody. Islets implanted into nonimmunosuppressed hosts completed revascularization by days 3-7 after transplantation, as shown by the detection of endothelial cells within and surrounding the islets. The identical staining pattern of revascularization was observed in nonrejecting allografts as well as in isografts treated with CsA. We conclude that CsA did not inhibit the process of revascularization of rat islets after free transplantation. This finding is relevant for human islet transplantation, where CsA is currently employed to prevent kidney and islet allograft rejection.