Gel capsule for diabetes type 1

Jun 23 2007

There is renewed hope for treatment of diabetes type 1 with gel capsules: Biotechnologists at The Norwegian University of Science and Technology (NTNU) have developed a new type of alginate capsule that could solve the problem of the body's immune system recognizing and attacking alien, implanted insulin cells.

If this becomes a medical reality, diabetes patients with transplanted insulin-producing donor cells in their abdominal cavity do not have to take immunosuppressants for the rest of their life – medication which involves a high risk of infections and cancer.

Researchers also envision using the innovation in the treatment of certain types of cancer.

The new capsule, called TAM (the Trondheim Alginate Microcapsule), is designed with a view to camouflage the insulin-producing cells to the body’s immune system.

”If the capsule is to function well, it needs to be suitably porous so that it allows nutrients to enter the insulin cells while insulin is transported out. It must be suitably small, and it must be stabile so it doesn’t swell and gradually break. We seem to be in the process of solving all these challenges," says Research Fellow Yrr Mørch from the Capsule Group at NTNU.

Her research environment, headed by Professor Gudmund Skjåk-Bræk, participates in an international cooperation called «The Chicago Project». The aim is to find a functional cure for diabetes type 1.

Alginate capsules with insulin cells are currently not used in the treatment of diabetes patients, even though the idea is far from new. As early as in the 1990s, an American had an alginate capsule with insulin cells produced in Trondheim implanted.

It appeared to be a success, but how well the old capsule actually functioned remained unanswered as the American had also had a kidney transplant and already took immunosuppressants.

Animal experiments later revealed that the capsule did not function satisfactorily. The main reason being polylysine, a substance used on the capsule’s outside to improve stability and make it less porous. This substance is toxic and triggers the immune system, which results in immune cells attaching to the capsule surface and hampering the diffusion of substances in and out of the capsule. The result is cell death.

Thorough basic research and several doctoral degrees later, the solution to the immune problem related to the transplant of capsules with insulin producing cells appears to be close. However, many years are likely to pass before the method can be used in patients. Stay updated on the development at: www.ntnu.no/forskning/alginatkapsler

Alginate is a long sugar molecule that stiffens kelp in the same way as cellulose makes the trees stand upright. Kelp has been researched at NTNU/former NTH for 50 years. Several of the alginate’s secrets are therefore revealed, including its structure.

Researchers have managed to isolate, clone and produce in large scale an enzyme involved in the construction of the alginate in different ways. That means that the researchers themselves can build the nanostructure of alginate so the molecule gets the desired properties.

Researchers envision tailoring different alginate capsules for individual use in the near future.

By Nina Tveter/Gemini