Researchers reverse diabetes in mice

Nerve cells in the pancreas may be a cause of type-1 diabetes in mice - a finding that could provide new ways to treat the disease in humans, Canadian and U.S. scientists said on Friday.

Defective nerve endings may attract immune system proteins that mistakenly attack the pancreas, destroying its ability to make insulin, the researchers said. This destruction is what causes diabetes.

Injecting a piece of protein, or peptide, to repair the defect cured diabetic mice "overnight", Dr. Hans Michael Dosch of the University of Toronto said in a telephone interview.

"It is very effective in reversing diabetes," said Dosch, principal investigator for the study.

Writing in the journal Cell, Dosch and colleagues said the faulty nerve endings did not secrete enough of the peptides to keep enough insulin flowing.

Type-1 diabetes, once called juvenile diabetes, affects two million Americans and 200,000 Canadians. There has been no known way of preventing it.

The team will soon begin clinical studies on people whose family history suggests they are at risk of developing type-1 diabetes to see if their sensory nerves work well.

If they do not, Dosch said, that would suggest the bad nerve endings were a cause of diabetes, not only an effect as has been widely assumed.

Trials could then begin injecting peptides into patients with diabetes or those at high risk. It could take a number of years, Dosch said.

He said the findings might also hold promise for type-2 diabetes - which affects about 10 times as many people as type-1 - though the results were not as strong.

The researchers found that the peptide injections lowered resistance to insulin, which is used to move blood glucose to the body's cells.

People with type-2 diabetes often are obese. By lowering insulin resistance, it might be possible to prevent further obesity and damage from diabetes.

"Whether we can reverse the process, I don't know. But I think we can certainly impact on the major physiological problem, and that's insulin sensitivity," Dosch said.

"So if these people then have normal insulin, then a little activity, then a little walking would actually help lose weight, and then you stop the vicious circle."