Prolongation of islet graft survival using concomitant transplantation of islets and vascular endothelial cells in diabetic rats.

ABSTRACT

BACKGROUND: The transplantation of isolated islets of Langerhans is nearing acceptance as treatment of type 1 diabetes mellitus. Because the arterial and venous connections of the pancreas are disrupted during islet isolation, islets must be revascularized after transplantation. OBJECTIVE: To observe whether increased numbers of vascular endothelial cells in islets can affect the angiogenesis and function of the grafts. MATERIALS AND METHODS: Rats with streptozocin-induced diabetes were divided into 3 groups. The rats in group 1 received islet grafts under the capsule of the left kidney; rats in group 2 received combined vascular endothelial cell and islet transplants; and rats in group 3 served as controls. After the transplantation procedure, blood glucose and insulin concentrations were evaluated daily. Hematoxylin-eosin and immunohistochemical staining was used to detect expression of vascular endothelial growth factor antibodies in the diabetic rat kidneys. The mean microvascular density was also calculated. RESULTS: At 3 days posttransplantation, blood glucose and insulin concentrations returned to normal in group 2, however, they declined only slightly in group 1, and moderate hyperglycemia was present. There was a significant difference in blood glucose and insulin concentrations between the 2 groups after 3 days (P < .05). The mean (SD) microvascular density in group 2 was markedly higher than that in group 1 (12.58 [1.81] vs 10.38 [0.97] P = .04). CONCLUSION: This study suggests that concomitant transplantation of isolated islets with endothelial cells can prolong islet graft survival in diabetic rats.