Scientists verify controversial diabetes therapy in mice

Three groups of scientists report today that they independently replicated a controversial finding: Severely diabetic mice can recover on their own if researchers squelch an immune system attack that is causing the disease.

It is a discovery that was first published in 2001 and raised the hopes of people with Type 1 diabetes, which usually occurs in puberty and afflicts an estimated half-million to a million Americans. If the findings applied to humans, they might mean reversing a disease that had seemed incurable.

The findings also gave rise to questions about using embryonic stem cells as replacement cells for diabetics, a method that is the focus of intense interest. If it is possible, in mice, for the pancreas to cure itself, and if the same finding holds true in humans — which, so far, is entirely unknown — adding embryonic stem cells as the source of new pancreas cells might provide little added benefit, if any.

In any event, scientists are not yet ready to treat diabetic patients with embryonic stem cells; they first have to prod the cells to turn into insulin-secreting pancreas cells. Meanwhile, efforts to cure diabetes by transplanting pancreas cells from cadavers have met with limited success.

The report several years ago, by Dr. Denise Faustman of Massachusetts General Hospital, that the pancreas might cure itself, at least in mice, met with skepticism.

"People just didn't believe it," said Dr. David Nathan, director of the diabetes center at Massachusetts General and a longtime supporter of Faustman's. "People said you can't cure diabetes."

But, Nathan added, "this shows that at least in mice it has been confirmed and reconfirmed and confirmed again."

The three new papers, by researchers at the University of Chicago, Washington University in St. Louis, and Harvard's Joslin Clinic are published today in Science. In every case, the investigators followed Faustman's procedures, injecting diabetic mice with Freund's Complete Adjuvant, a mixture of water, oil and parts of dead bacteria. It overstimulates the immune system cells that are attacking the pancreas, making those white blood cells self-destruct, effectively stopping the attack and allowing the pancreas to heal itself.

The different groups calculated their cure rates in different ways but all reported that a significant proportion, though less than half of the mice, were cured. In Faustman's experiments, 67 percent of the mice were cured.

Dr. John Buse, director of the Diabetes Care Center at the University of North Carolina, urged caution.