Transplant Advance for Type 1 Diabetes: Report
Used in single patient, special chamber may allow implantation of insulin-producing cells without rejection
To try to make the implant procedure available to more people, the researchers designed a semi-permeable chamber to house the islet cells, with the hope that the immune system wouldn't be able to "see" the new foreign cells.
However, when islet cells are first transplanted, they haven't established their own blood supply and aren't able to get oxygen when they're hiding in the chamber. For that reason, the current version of the device had an oxygen port on the outside of the body attached via tubing that had to be refilled daily by the patient for as long as a month or two, Block explained.
The device was implanted into a 63-year-old man, who'd had type 1 diabetes for 54 years. He was of average weight, and didn't have any serious complications from his diabetes.
Blood tests for a substance called C-peptide showed he wasn't producing any of his own insulin. C-peptide is a byproduct of insulin production, and is often used to measure the success of diabetes treatments in research settings. If C-peptide levels rise, it means insulin production has risen.
The transplant recipient had modest increases in his C-peptide levels, and the levels of C-peptide and insulin rose rapidly in response to an injection of glucose (a form of sugar). Over time, his long-term blood sugar control improved slightly, and his need for insulin decreased, though not to the point where he didn't need insulin injections.
What was remarkable, however, was that after 10 months, there were no signs that the immune system was aware of the new cells. There were no signs of possible rejection of the new cells, and no signs that the immune system initiated an attack on the new islet cells.
The transplant only contained about half the amount of islet cells normally transplanted. "We only had a limited number of beta cells available from this one pancreas," explained Block, a distinguished professor of urologic research and clinical director of the Endocrine Polypeptide and Cancer Institute at the Veterans Affairs Medical Center Research Service, in Miami.