A Pancreas in a Capsule

Stem-cell advocates pin their hopes on an artificial pancreas to treat diabetes.

Fourteen years ago, during the darkest moments of the stem-cell wars pitting American scientists against the White House of George W. Bush, one group of advocates could be counted on to urge research using cells from human embryos: parents of children with type 1 diabetes. Motivated by scientists who told them these cells would lead to amazing cures, they spent millions on TV ads, lobbying, and countless phone calls to Congress.

Now the first test of a type 1 diabetes treatment using stem cells has finally begun. In October, a San Diego man had two pouches of lab-grown pancreas cells, derived from human embryonic stem cells, inserted into his body through incisions in his back. Two other patients have since received the stand-in pancreas, engineered by a small San Diego company called ViaCyte.

Its a significant step, partly because the ViaCyte study is only the third in the United States of any treatment based on embryonic stem cells. These cells, once removed from early-stage human embryos, can be grown in a lab dish and retain the ability to differentiate into any of the cells and tissue types in the body. One other study, since cancelled, treated several patients with spinal-cord injury (see Geron Shuts Down Pioneering Stem-Cell Program and Stem-Cell Gamble), while tests to transplant lab-grown retina cells into the eyes of people going blind are ongoing (see Stem Cells Seem Safe in Treating Eye Disease).

Type 1 patients must constantly monitor their blood glucose using finger pricks, carefully time when and what they eat, and routinely inject themselves with insulin that the pancreas should make. Insulin, a hormone, triggers the removal of excess glucose from the blood for storage in fat and muscles. In type 1 diabetics, the pancreas doesnt make it because their own immune system has attacked and destroyed the pancreatic islets, the tiny clusters of cells containing the insulin-secreting beta cells.

The routine is especially hard on children, but if they dont manage their glucose properly, they could suffer nerve and kidney damage, blindness, and a shortened life span. Yet despite years of research, there is still just nothing to offer patients, says Robert Henry, a doctor at the University of California, San Diego, whose center is carrying out the surgeries for ViaCyte.

Henry slightly overstates the case, but not by much. There is something called the Edmonton Protocol, a surgical technique first described in the New England Journal of Medicine in 2000. It used islets collected from cadavers; by transplanting them, doctors at the University of Alberta managed to keep all seven of their first patients off insulin for an entire year.

Early hopes for the Edmonton Protocol were quickly tempered, however. Only about half of patients treated have stayed off insulin long-term, and the procedure, which is still regarded as experimental in the U.S., isnt paid for by insurance. It requires recipients to take powerful immune-suppressing drugs for life. Suitable donor pancreases are in extremely short supply.

The early success of the Edmonton Protocol came only two years after the discovery of embryonic stem cells, in 1998. Those pressing for a diabetes cure quickly set a new goal: pair something like the Edmonton Protocol with the technology of lab-grown beta cells, the supplies of which are theoretically infinite.

This biocompatible capsule is designed to protect manufactured pancreas cells.

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A Pancreas in a Capsule