Teflon-Coated Pancreatic Cells Cure Diabetes in Mouse Models

Diabetes researchers transplanted pancreatic beta-cells encapsulated in a Teflon (polytetrafluorethylene) coating into mouse models of type I diabetes and found that the beta-cells matured into insulin producing cells without triggering the host animal's immune response.

While transplantation of pancreatic tissue has long been cited as a potential treatment for diabetes, this approach suffers from the need for chronic immunosuppression and the lack of suitable donor tissue.

Investigators at the University of California, San Diego (La Jolla, USA) devised a method for circumventing the need for long-term immunosuppressive therapy. Their solution was to sequester immature pancreatic beta-cells inside a Teflon coating before transplantation.

In a preliminary study the cells were injected into normal mice in order to demonstrate the lack of an immune response. Then, the encapsulated cells were transplanted into immunodeficient mice to study the viability and function of both mature beta cells and precursor cells inside the capsules. Graft survival and function were measured by immunohistochemistry, circulating human C-peptide levels, and blood glucose levels. Bioluminescent imaging was used to monitor encapsulated neonatal murine islets.

The investigators reported in the April 15, 2009, issue of the journal Transplantation that encapsulated human islet-like cell clusters survived, replicated, and acquired a level of glucose responsive insulin secretion sufficient to resolve hyperglycemia in diabetic mice. Bioluminescent imaging of encapsulated murine neonatal islets revealed a dynamic process of cell death followed by regrowth, resulting in robust long-term survival of the grafted cells.

In the non-obese diabetic (NOD) mouse model of type I diabetes, encapsulated primary beta-cells cured diabetes without stimulating a detectable T-cell response.

"The results exceeded our expectations," said senior author Dr. Pamela Itkin-Ansari, assistant professor of medicine at the University of California, San Diego. "We thought that T-cells, although unable to penetrate the device, would cluster around it. But we found no evidence of an active immune response, suggesting that the cells in the device were invisible to the immune system."

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