Objectives: The purpose of this study was to evaluate the functional significance of the renal capsular vessels in renal subcapsular islet grafts.
Methods: Syngeneic islets were transplanted under the left renal capsule of diabetic Wistar-Furth rats. At 4 weeks post-transplantation, the left renal artery and vein were ligated (group A); in group B, the left renal capsule was dissected to remove capsular vessels; or both were performed in group C. Controls included ligation of the right renal vessels (group D).
Results: : All recipients achieved normoglycemia post-transplantation. Treatments for groups A, B, and D did not result in significant changes in glycemia and glucose tolerance. In contrast, all rats in group C returned to hyperglycemia immediately post-treatment. Insulin contents in grafts harvested at 10 days post-treatment in groups A and B were significantly lower than those in group D but higher than those in group C. Histologic examination revealed well-preserved insulin-positive cells under the capsule of necrotic kidney at 8 weeks post-treatment in group A.
Conclusions: Renal subcapsular islet grafts do not acquire their blood supply solely from the renal artery but rather from the renal capsular arteries as well. Not only renal veins but also renal capsular veins play a role as effluent vessels from these grafts.