Cell Transplants for Type 1 Diabetes

Sept. 8, 2004 -- Transplants of healthy, specialized pancreatic cells can help people with type 1 diabetes make their own insulin, at least for a while, according to a new study.

Type 1 diabetes occurs when the body's immune system destroys insulin-producing cells in the pancreas. For many years, there's been great interest in replacing insulin-producing cells in people with diabetes. Approaches like whole pancreas organ transplants have been successful yet are fraught with complications.

Now, researchers from 12 medical centers in the U.S. and Canada report on their long-term success in an experimental procedure that infuses insulin-producing pancreatic cells into patients with type 1 diabetes.

In the study, eighty-six people with type 1 diabetes received transplants of islet cells, which are the cells in the pancreas that produce insulin.

After six months, 61% of the patients still didn't need insulin injections. The functioning islet cells were able to make appropriate amounts of insulin. After one year, 58% didn't need insulin injections.

It's not yet known how long the results will last. Researchers are continuing to monitor the patients.

Participants were 42 years old, on average. They had had type 1 diabetes for an average of 30 years; 66% were women.

In the year before the procedure, more than 67% had experienced at least one episode of blood sugar that was so dangerously low that another person's help was needed.

Understanding Type 1 Diabetes

Type 1 diabetes typically strikes in childhood or young adulthood. Up to 1 million Americans have type 1 diabetes.

Since people with type 1 diabetes can't make their own insulin, they have to inject it several times a day or use insulin pumps.

It's not always easy to figure out how much insulin is needed during the day, so people with diabetes must check their blood sugars throughout the day as a guide to how much insulin is needed.

Complications of type 1 diabetes can include damage to the heart and blood vessels, eyes, nerves, and kidneys.

Transplanting the Cells

Study participants received between one and three transplants of healthy islet cells.

The cells were infused through the liver. When the procedure worked, the cells set up shop in the liver's blood vessels and start making insulin as if they'd been there all along.

Of the study's participants, 28 had one islet infusion, 44 got two infusions, and 14 received three. Among those who were insulin-free, some still had higher-than-normal blood sugar levels.

No participants died in the year after their procedure, and most side effects were linked to either the operation itself or the drugs taken to coax the patients' bodies into accepting the cells.

Rare Procedure

Worldwide, fewer than 750 such transplants have been performed on patients with type 1 diabetes. Most were done in small trials.

Supply is part of the problem. Only about 6,000 donated pancreases are available each year, according to a news release from the National Institutes of Health.