Encapsulated Human Islet Cells Halt Diabetes for 6 Months in Mice

Researchers from the Massachusetts Institute of Technology (MIT), Boston’s Children Hospital, and several other institutions have successfully used human pancreatic islet cells encased in a porous capsule to halt Type 1 diabetes in mice without causing an adverse immune response for six months. These experiments been reported in two separate scientific journals.

The first study utilized a modified alginate material to encapsulate the pancreatic islet cells. Alginate is a material that originally was derived from brown algae, and has been used to encapsulate cells without harming them or preventing them from sensing and responding to biochemical signals.

Despite all these advantages to alginate, nonspecific kept theior immune responses against it eventually result in the build up of scar tissue around alginate capsules that renders any implanted cells placed inside them ineffective.

The MIT group tested modified alginate derivatives that would not elicit this nonspecific immune response. From a library of over 800 alginate derivatives, the group came upon one particular alginate derivative called triazolethiomorpholine dioxide (TMTD).

To test TMTD capsules in diabetic mice, The MIT group teamed up with Harvard researcher Doug Melton, who supplied human pancreatic beta cells derived from human embryonic stem cells. Once the TMTD-encased beta cells were implanted into mice suffering from type 1 diabetes, the cells immediately began producing insulin in response to increases in blood glucose levels. Diabetic, laboratory mice with these islet cell TMTD-encased implants kept their blood glucose levels within a healthy range for 174 days, which was the whole length of the study.

“Encapsulation therapies have the potential to be groundbreaking for people with Type 1 Diabetes. These treatments aim to effectively establish long-term insulin independence and eliminate the daily burden of managing the disease for months, possibly years, at a time without the need for immune suppression,” said Julia Greenstein, an executive with the Juvenile Diabetes Research Foundation, who funded these two studies.

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