Implants containing specially wrapped insulin-producing cells derived from embryonic stem cells can regulate blood sugar in mice for several months, according to research presented this month at the International Society for Stem Cell Research conference in San Francisco. San Diego-based ViaCyte (formerly Novocell), which is developing the implant as a treatment for type 1 diabetes, is now beginning the safety testing required for approval from the U.S. Food and Drug Administration before human testing can start.
|Replacing the pancreas: Insulin-producing cells (shown here marked in blue), derived from stem cells and encapsulated in a special membrane, might one day regulate blood sugar in type 1 diabetics. |
"It's still a long road toward a treatment for diabetes, but in my mind they have made astonishing progress," says Gordon Weir, head of Islet Transplantation and Cell Biology at Joslin Diabetes Center, in Boston. But he cautions that taking the next step is likely to be tricky. The technology "tends to work well in rodents, but moving it to larger animals gets more complicated," says Weir, who is not involved with the company. "You need more cells, and we're guessing the immune system [reaction] is more complex."
In type 1 diabetes, the immune system attacks the insulin-producing beta cells of the pancreas, forcing patients to rely on injections of the hormone to regulate blood sugar. Transplants of pancreatic cells from cadavers to human patients have shown that this type of cell therapy can free type 1 diabetics from daily insulin injections. But the scarcity and variable quality of this tissue makes it an impractical therapy. For the last two decades, scientists have searched for alternative sources of cells, focusing in large part on cells from the pancreas of fetal or neonatal pigs. ViaCyte, which began its efforts more than 10 years ago, has focused on embryonic stem cells.