Original Article Donor Islet Endothelial Cells Participate in Formation of Functional Vessels Within Pancreatic Islet Grafts

Pancreatic islet transplantation has emerged as a ther-apy for type 1 diabetes and is today performed using both freshly isolated and cultured islets. Islet blood vessels are disrupted during islet isolation; therefore, proper revascularization of the transplanted islets is of great importance for islet graft function and survival. We have studied intraislet endothelial cells after islet isolation, during islet culture, and following islet trans-plantation. By isolating islets from the transgenic Tie2-GFP (green fluorescent protein) mouse, characterized by an endothelial cell–specific expression of GFP, living endothelial cells could be studied in intact islets utiliz-ing two-photon laser-scanning microscopy (TPLSM). Intraislet endothelial cells were found to survive islet transplantation but to rapidly disappear during isle