Cell implantation

Doctors in Germany used a special chamber system to implant insulin-producing cells in a patient without the need for immunosuppressant drugs. A new study reports the results. (Courtesy PNAS)

German doctors have successfully implanted insulin-producing cells in a patient with Type 1 diabetes using a specially constructed chamber system that does not require the use of immunosuppresant drugs, according to a new study.

In a paper published Monday in the journal PNAS, researchers said the islets, or clusters of cells, remained alive for 10 months and were not rejected by the 56-year-old patient's immune system. However, the implantation offered only moderate health improvements and requires further refinement.

"This approach may allow for future widespread application of cell-based therapies," wrote lead author Dr. Barbara Ludwig of the German Center for Diabetes Research in Dresden and her colleagues.

Diabetes mellitus Type 1 is an autoimmune disease that results in irreversible destruction of insulin-producing beta cells. Attempts to implant donor cells have met with two large hurdles: lack of eligible donors and the need for lifelong medication to suppress the body's immune system and prevent it from destroying the implanted cells.

The plastic disk-like device, which resembles a small puck or air-freshener, measures just more than 2 1/2 inches in diameter and more than half an inch thick. Within the container are two layers of donor cells surrounded by alginate, a semi-permeable coating that allows the cells to secrete insulin. The insulin exits the plastic disc through numerous perforations.

Two layers of cells are separated by an oxygen capsule that must be refilled daily by the patient through a tube, or port. The oxygen is able to permeate the protective alginate that surrounds the donor cells.

The patient was a 56-year-old mathemetician who has been involved with the development of other diabetese technology. He carried the implant for 10 months before it was removed and examined by doctors.

The removed cells were intact and healthy, according to researchers, and the implant itself was "well tolerated" by the patient, authors said. "Despite the absence of using any immunosuppressive agents, no signs of graft rejection or immune sensitization of the recipient were observed," the authors wrote.

The implanted cells showed evidence of insulin production but showed only a "minimal systemic effect."

Authors say that performance may be improved by adding more cells to the device and by placing it deeper in the patient's abdomen.