Major Advance May Enable Safe Islet Transplants to Cure Type 1 Diabetes; CXCL12-Encapsulated Islets Protect Insulin-Producing Cells from Recipient’s Immune Response

An approach developed by Massachusetts General Hospital (MGH) investigators may provide a solution to the limitations that have kept pancreatic islet transplantation from meeting its promise as a cure for type 1 diabetes. In the March 2015 issue of the American Journal of Transplantation, the research team reports that encapsulating insulin-producing islets in gel capsules, infused with a protein that repels key immune cells, protected islets from attack by the recipient's immune system, without the need for immunosuppressive drugs, restoring long-term blood sugar control in mouse models. The technique was effective both for islets from unrelated mice and for islets harvested from pigs. "Protecting donor islets from the recipient's immune system is the next big hurdle toward making islet transplantation a true cure for type 1 diabetes," says Mark Poznansky, M.D., Ph.D., Director of the MGH Vaccine and Immunotherapy Center, who led the study. "The first was generating enough insulin-producing islets, which has been addressed by several groups using pig islets, or, as announced last fall by Doug Melton's team at the Harvard Stem Cell Institute, with islet cells derived from human stem cells. Now our technology provides a way to protect islets or other stem-cell-derived insulin-producing cells from being destroyed as soon as they are implanted into a diabetic individual, without the need for high-intensity immunosuppression, which has its own serious side effects." While transplantation of pancreatic islets has been investigated for several decades, as a treatment and potential cure for type 1 diabetes, its success has been limited.
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