Researchers at the Massachusetts Institute of Technology (MIT) and Boston Children’s Hospital, have designed a novel material for encapsulation of pancreatic cells, which may allow the cells to be transplanted into patients with type 1 diabetes. The researchers tested the encapsulated human cells in diabetic mice and found that the disease could be cured for six months, and the transplanted cells did not elicit an immune response.
Type 1 diabetes is an autoimmune disease in which the body’s immune system attacks and destroys the insulin-producing cells – known as islet cells – within the pancreas. Patients with type 1 diabetes must monitor their blood glucose levels throughout the day and ensure sugar levels stay in a healthy range by injecting insulin.
While researchers have previously tried to effectively cure the disease by replacing the damaged pancreatic islet cells with functional cells capable of monitoring blood sugar levels and secreting insulin, this treatment option has a definite drawback. The implanted islet cells often elicit an immune response, requiring those patients to take immunosuppressant medications for the duration of their lives.
According to Daniel Anderson, the Samuel A. Goldblith Associate Professor in MIT’s Department of Chemical Engineering, the islet cell encapsulation 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.” Previous cell implants were encapsulated in alginate – a compound derived from a specific type of algae – which were ineffective due to their tendency to accumulate scar tissue.
In order to develop a better material for encapsulation, the researchers created a library of almost 800 alginate derivatives in the hope that one would be effective at protecting the cells while bypassing the immune system. “We decided to take an approach where you cast a very wide net and see what you can catch,” said Arturo Vegas, an assistant professor at Boston University who completed his postdoc MIT and Boston Children’s Hospital. “We made all these derivatives of alginate by attaching different small molecules to the polymer chain, in hopes that these small molecule modifications would somehow give it the ability to prevent recognition by the immune system.”
The researchers chose a compound known as triazole-thiomorpholine dioxide (TMTD) for further study in mice. They implanted the TMTD-encapsulated pancreatic islet cells into the abdominal cavity of diabetic mice bred to have a strong immune system. The implanted cells were able to control blood glucose levels for 174 days – the duration of the study.
“The really exciting part of this was being able to show, in an immune-competent mouse, that when encapsulated these cells do survive for a long period of time, at least six months,” said Omid Veiseh, a senior postdoc at the Koch Institute and Boston Children’s hospital. “The cells can sense glucose and secrete insulin in a controlled manner, alleviating the mice’s need for injected insulin.”
The next step is for this technology to be tested in other primates, and eventually humans. If results of further studies are positive, the encapsulation technique could be a viable treatment option for type 1 diabetes.