Edmonton, Canada – A cross-border collaboration between researchers at the University of Alberta and Cornell University has successfully created a device which, once implanted under the skin, can secrete insulin without triggering an immune response.
In a paper published in the journal Nature Biomedical Engineering, the scientists, led by James Shapiro of the U of Alberta and Minglin Ma at Cornell University, report the device could someday make transplants of insulin-producing cells more accessible — and safer — for those living with diabetes. The scientists report sustained cell survival and diabetes reversal in mice that received subcutaneous islet transplants from other mice, rats and humans without the use of anti-rejection drugs.
Many patients who have undergone similar transplantations, such as through the Edmonton Protocol, no longer need to take insulin injections, but they face a lifetime of anti-rejection drugs, making them more vulnerable to infection and even cancer.
“If we could do a transplant with less or no anti-rejection drugs, we could do it much more safely, and we could include more patients who could benefit,” says Shapiro, the Canada Research Chair in Transplant Surgery and Regenerative Medicine who also leads the Edmonton Protocol.
Most successful islet cell transplants are currently grafted into the liver, but it is hard to monitor or remove the transplanted cells from the internal organ. This new research combines groundbreaking work by Shapiro and Ma to make the transplantation technique more accessible: Shapiro’s team’s created a potential alternative transplant site under the skin by placing a plastic tube in the forearm, allowing blood vessels to form around it, then removing the device and leaving behind a vascularized pocket for transplantation. Ma’s team created a removable polymer thread containing thousands of islet cells protected by a thin hydrogel coating that could be implanted into a patient’s abdomen without triggering an immune response.
“I was intrigued by the virtue of Ma’s approach as it avoided the need for immunosuppression, and I wondered if we might combine our two innovative strategies to improve cell survival,” recalls Shapiro. “And indeed it worked! By combining the two, it really did improve the skin site for engrafting cells without the need for anti-rejection drugs. The data are very compelling.”
Shapiro cautions that while the results seem promising, the method needs to be further tested in larger animals, and eventually in humans, to know its full potential. The teams have named their new combined approach “SHEATH,” which stands for subcutaneous host-enabled alginate thread. There is hope the new method could also be tested for transplants of other types of hormone-producing cells for diseases such as anemia and chronic renal disease.
Contact
Sarah Vernon
University of Alberta
[email protected]