Daily insulin injections for Type 1 diabetes patients are interruptive and ineffective at maintaining healthy blood sugar levels for long periods. 

Replacing the patients’ destroyed pancreatic islet cells with healthy cells would be a better option, but because their immune systems will attack the transplanted cells, the patients would end up trading their insulin for immunosuppressant drugs.

In an effort to resolve this issue, researchers from MIT, Boston Children’s Hospital and several other institutions have developed a way to protect the transplanted pancreatic cells from the immune system.

The researchers designed a material that encapsulates the islet cells before they are transplanted. Testing in mice showed that the encapsulated cells could cure diabetes for up to six months without an immune response.

This approach “has the potential to provide diabetics with a new pancreas that is protected from the immune system, which would allow them to control their blood sugar without taking drugs. That’s the dream,” said Daniel Anderson, associate professor of chemical engineering at MIT and senior author of two studies describing the research.

Encapsulating Pancreatic Islet Cells

The researchers started with chemical derivatives of alginate, a material originally isolated from brown algae, which can encapsulate cells without harming them. Molecules like sugar and proteins can also move through the alginate gels, which makes responses to biological signals possible.

Normally, scar tissue forms around the capsule and eventually makes it ineffective. To combat this, the researchers explored numerous modifications of the alginate to make it less likely to cause an immune response.

Of the 800 alginate derivatives they created, the researchers chose triazole-thiomorpholine dioxide (TMTD) to test on mice with strong immune systems. Human islet cells encapsulated in TMTD were implanted into a region of the abdominal cavity known as intraperitoneal space. Following implantation, the cells immediately produced insulin in response to blood sugar levels and continued to do so for 174 days.

Insulin Independence

Further tests with the new method in nonhuman primates will eventually lead to clinical trials in diabetic patients. If these studies are successful, diabetes patients will have a newfound freedom from insulin shots.

The researchers are still investigating why the new material works so well; the best-performing materials were modified with molecules containing a triazole group, which is a ring containing two carbon atoms and three nitrogen atoms. Their current hypothesis is that this class of molecules interferes with the immune system’s ability to recognize the material as foreign.