Renal subcapsular islet cell transplantation.

Islet cell transplantation has been associated with ultimate graft rejection. This preliminary study investigates the use of the renal subcapsular region as a site for placement of canine islet cell allografts. A new noncollagenase mechanical technique was used for preparation of the allografts. Animals in group I (N = 6) died of hyperglycemia in 4.0 +/- 1.89 days (X +/- SD) after pancreatectomy without subsequent islet cell transplant. Normoglycemia and excellent survival (greater than 60 days) was obtained in pancreatectomized animals in group II (N = 6) and in group III (N = 6), who received an islet cell allograft to the renal subcapsular site. Group II recipients were given no immunosuppression, and animals in group III received minimal immunosuppression with azathioprine. Dependence on the islet cell allograft for maintenance of normoglycemia was confirmed in the majority of the recipients by nephrectomy, to remove the graft, with resulting hyperglycemia and death. One normoglycemic animal in group II died on day 6 from peritonitis. One recipient in group II was normoglycemic at greater than 1 mo after removal of the first graft by nephrectomy, followed by retransplantation of islet cells from a third-party donor. Two other recipients are being studied on a long-term basis, and have been normoglycemic for greater than 6 mo and greater than 4 mo after transplantation. These studies encourage further investigation in this area for application of islet cell transplantation in man, and elucidation of the possible mechanisms for prolongation of islet cell allograft survival at the renal subcapsular site.