Findings published Jan. 29 in Science Advances from a team lead by senior author Dr. Shahin Rafii, chief of the division of Regenerative Medicine, found that adding engineered human blood vessel-forming cells to islet transplants boosted the survival of the insulin-producing cells and reversed diabetes in a preclinical study. The new approach, which requires further development and testing, could someday enable the much wider use of islet transplants to cure diabetes.
Islets, found in the pancreas, are clusters of insulin-secreting and other cells enmeshed in tiny, specialized blood vessels. The insulin cells are killed by an autoimmune process in type 1 diabetes, which affects roughly nine million people worldwide. Although islet transplantation is a promising approach for treating such cases, the only FDA-approved method to date has significant limitations.
The study’s research showed that special blood vessel-forming cells they developed, called “reprogrammed vascular endothelial cells” (R-VECs), can overcome some of these limitations by providing strong support for islets, allowing them to survive and reverse diabetes long-term when transplanted under the skin of mice.
“This work lays the foundation for subcutaneous islet transplants as a relatively safe and durable treatment option for type 1 diabetes,” said first author Dr. Ge Li, a postdoctoral research associate in Dr. Rafii’s laboratory.
In the study, Drs. Li and Rafii and their colleagues demonstrated the feasibility of long-term subcutaneous islet transplants using R-VECs as critical support cells. “We showed that vascularized human islets implanted into the subcutaneous tissue of mice that were immune-deficient promptly connected to the host circulation, providing immediate nutrition and oxygen, thereby enhancing the survival and function of the vulnerable islets,” said Dr. Rafii. Indeed, derived from human umbilical vein cells, R-VECs are relatively durable in transplant conditions—unlike the fragile endothelial cells found in islets—and are engineered to be highly adaptable, supporting whatever specific tissue type surrounds them.
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