Encapsulated pancreatic cells could replace injections for diabetes patients - Medical News

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Friday, January 12, 2018

Encapsulated pancreatic cells could replace injections for diabetes patients

pancreatic cells

In a breakthrough diabetes research, a team of scientists from Harvard University, MIT, as well as from Boston Children's Hospital and other centers has designed a biomaterial that can be used to encapsulate human pancreatic cells before transplanting them.

Animal tests have shown that the implanted human pancreatic cells can combat attack by the immune system in mice for up to 6 months, while maintaining their ability to sense low blood sugar and produce insulin in response.

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Type 1 diabetes happens when the islet cells located in oura pancreas, are attacked by the immune system, and renders them unable to produce insulin. Our body needs insulin – a type of hormone – to regulate glucose (blood sugar).

Type 1 diabetes requires lifelong treatment to keep blood sugar levels within a target range. Several times each day, patients with the disease are required to check their glucose level, and to keep the level from getting too high, they need to inject themselves with insulin.


One of the methods to improve type 1 diabetes treatments is by replacing the damaged islet cells with healthy cells that is able to bring back their ability to monitor glucose and release insulin. However, after trying in numerous patients, the success of this method was found to be limited because of the fact that the patients needed to take immunosuppressant medications for the rest of their lives.

This newly discovered biomaterial is a by-product of alginate – a substance originally derived from brown algae. Researchers discovered that cells can be encapsulated with Alginate gels without injuring them and also permit molecules like proteins and sugar to move through, enabling cells to sense and retort to biological changes.


However, during the testing phase when gel capsules were implanted in humans and primates, the researchers found that scar tissues eventually covers the surfaces of the capsule, blocking molecules to pass through and reducing the effectiveness of encapsulated devices.

pancreatic cells


The research team explained how they tested numerous different types of alginate in the paper Nature Biotechnology.

All the alginate derivatives were made by attaching various small molecules to the chain of polymer, hoping that these modifications would make them invisible to the immune system, explains Arturo Vegas of Boston University.


After building a library of almost 800 derivatives of alginate, the scientists performed several tests in mice and primates. One of the best alginate derivative, called TMTD (triazole-thiomorpholine dioxide), was used in tests on diabetic mice.

They picked a strain of these rodents with a powerful immune system and then into their abdominal cavity, they implanted TMTD-encapsulated human islet cells.

Following implantation, in response to glucose, the cells immediately started making insulin and kept blood glucose under control for 174 days – the entire study period.

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The exciting part was being able to display that in immune-competent mice, encapsulated cells do survive for an extended period, at least 6 months, said Omid Veiseh of the Boston Children’s Hospital.


The biomaterial was also tested as empty capsules, when the researchers implanted it into the abdominal chambers of primates. These capsules persisted for at least 6 months and did not accumulate scar tissue.

Researchers wanted to find out why this new biomaterial worked so well. They found that the triazole ring present in it may impede the immune system from recognizing the substance as foreign.
Senior research associate, Robert Langer, of Boston Children’s Hospital said the combination of results from the two papers show that these capsules can really shield transplanted cells in humans.

The next step for the team is to further test these materials in primates, aiming to eventually perform clinical trials in humans with diabetes.

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