Hydrogel biomaterial shows promise for Type 1 diabetes treatment

May 14, 2013

Immunostained image of engrafted islet in hydrogel in diabetic mouse. (Red areas are insulin-producing cells. Green areas are blood vessels, and blue areas are DNA nuclei in cells.) (Credit: Georgia Tech)

Georgia Tech engineers and Emory University clinicians have successfully transplanted insulin-producing cells into a diabetic mouse model, reversing diabetic symptoms in the animal in as little as 10 days.

It could help lead to a possible cure for Type 1 diabetes.

The research team engineered a biomaterial to protect the cluster of insulin-producing cells — donor pancreatic islets — during injection. To foster blood vessel formation, the material also contains proteins  that allow the cells to successfully graft, survive and function within the body.

The hydrogel material is compatible with biological tissues that is a promising therapeutic delivery vehicle. This water-swollen, cross-linked polymer surrounds the insulin-producing cells and protects them during injection.

The hydrogel containing the islets was delivered to a new injection site on the outside of the small intestine, thus avoiding direct injection into the blood stream.

Once in the body, the hydrogel degrades in a controlled fashion to release a growth factor protein that promotes blood vessel formation and connection of the transplanted islets to these new vessels. In the study, the blood vessels effectively grew into the biomaterial and successfully connected to the insulin-producing cells.

Four weeks after the transplantation, diabetic mice treated with the hydrogel had normal glucose levels, and the delivered islets were alive and vascularized to the same extent as islets in a healthy mouse pancreas. The technique also required fewer islets than previous transplantation attempts, which may allow doctors to treat more patients with limited donor samples. Currently, donor cells from two to three cadavers are needed for one patient.

While the new biomaterial and injection technique is promising, the study used genetically identical mice and therefore did not address immune rejection issues common to human applications. The research team has funding from JDRF to study whether an immune barrier they created will allow the cells to be accepted in genetically different mice models. If successful, the trials could move to larger animals.

“We broke up our strategy into two steps,” said Garcia, a member of Georgia Tech’s Petit Institute for Bioengineering and Bioscience. “We have shown that when delivered in the material we engineered, the islets will survive and graft. Now we must address immune acceptance issues.”

Type 1 diabetes is a chronic disease that occurs when the pancreas produces little or no insulin, a hormone that allows the transport of sugar and other nutrients into tissues where they are converted to energy needed for daily life.

Most people with Type 1 diabetes currently manage their blood glucose levels with multiple daily insulin injections or by using an insulin pump. But insulin therapy has limitations. It requires careful measurement of blood glucose levels, accurate dosage calculations and regular compliance to be effective.

This work was also funded by the Regenerative Engineering and Medicine Center at Georgia Tech and Emory, and the Atlanta Clinical and Translation Science Institute from the Clinical and Translational Science Award Program.

The Center for Pediatric Healthcare Technology Innovation at Georgia Tech, the Department of Veterans Affairs Merit Review Program and the National Institutes of Health’s National Institute of Diabetes and Digestive and Kidney Diseases helped fund the project as well.