Vascularization of Human Pancreatic Islets With Adaptive Endothelial Cells for In Vitro Analysis and In Vivo...

The pancreatic islet, the only type of tissue that secretes insulin in response to elevated blood glucose, plays a vital role in diabetes development and treatment. While various islet vascularization strategies have been developed, they have been hindered by major limitations such as relying on pre-patterning and the inability to span long distances. Furthermore, few strategies have demonstrated robust enough vascularization in vivo to support therapeutic subcutaneous islet transplantation. Using adaptive endothelial cells (ECs) reprogrammed by transient expression of the ETS Variant Transcription Factor 2 (ETV-2) gene, we have physiologically vascularized human islets within a generic microchamber and have achieved functional engraftment of human islets in the subcutaneous space of mice. Such adaptive ECs, which we term reprogrammed vascular ECs (R-VECs), have been proven to be a suitable tool for both in vitro disease modeling and in vivo transplantation of not only islets but also other organoids. Key features • This protocol contains two parts: the in vitro and in vivo parts, both utilizing adaptable endothelial cells to functionally vascularize human islets. • The in vitro portion of this protocol describes the method to culture human islets in a vascular bed within a large and commercially available microchamber. • The in vivo portion of this protocol provides a step-by-step procedure to reverse hyperglycemia in streptozotocin-induced diabetic mice.