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Insulin-producing pancreas cells destroyed by type 1 diabetes may have been regenerated in mice, thanks to a new cocktail of drugs. The work, which effectively cures mice of the disease, provides insights into the early stages of diabetes and could open up new options for treatment.

Type 1 diabetes is an autoimmune disease marked by the loss of insulin-producing islet beta cells in the pancreas. The drug cocktail works by neutralising the immune system鈥檚 attack on the beta cells, as well as taming the inflammation that accompanies the disease.

鈥淭he drugs work by neutralising the immune system鈥檚 attack on pancreatic beta cells and by taming inflammation鈥�

Until now, research has focused on transplanting beta cells from donors or even cadavers to replace those destroyed. But donors are in short supply, and people receiving transplants would have to take immunosuppressant drugs for life. Regenerating a person鈥檚 own beta cells is a far better solution.

Last year, Terry Strom and his colleagues at Harvard Medical School in Boston showed that a 鈥減ower mix鈥� of three drugs could adjust the proportions of the different types of immune cells, restoring the ability of regulatory cells to halt the attack on beta cells and taming the inflammation to some degree. Strom reported that the cocktail restored blood glucose levels to normal in more than 90 per cent of diabetic mice (Proceedings of the National Academy of Sciences, ). But halting the destruction of beta cells did not spark their regrowth, so beta cell numbers remained about 75 per cent below normal.

Strom subsequently decided to add an enzyme called alpha 1 anti-trypsin to the mix. The body produces this enzyme to ease inflammation, which it does by blocking the manufacture of various cytokine chemicals.

Inflammation is thought to influence the progression of diabetes in several ways. It might encourage too many immune cells to mature into cells that attack the pancreas. Inflammation also disrupts insulin signalling, so more glucose than usual remains in the blood. This could further damage beta cells, as glucose can be toxic at high concentrations. Strom hoped that by altering the body鈥檚 inflammatory response even further, he might provide the beta cells with a protective 鈥渦mbrella鈥� under which they could recover their numbers.

Strom gave newly diagnosed diabetic mice the power mix plus alpha 1 anti-trypsin for three weeks, then used a chemical stain to detect insulin production in their beta cells. Fifty days after the treatment ended, Strom saw a significant rise in the number of insulin-producing cells.

鈥淚t would appear that by altering the inflammatory state that surrounds this autoimmune disease, you can create an environment that enables expansion of the beta cell mass,鈥� says Strom, who presented his results in Berlin, Germany, last week at the . He says it is too early to judge whether beta cells that had stopped making insulin recovered or whether new beta cells were produced.

Either way, Strom鈥檚 finding could have major clinical significance. 鈥淚t would provide a new pathway for initial treatment of new-onset diabetic people,鈥� says Larry Turka, an immunologist at the University of Pennsylvania in Philadelphia.

鈥淭his is one of the first demonstrations that I鈥檓 aware of that the beta cell mass can be refurbished in type 1 diabetes following treatment,鈥� Strom says. Clinical trials are now planned.