New research into cell differentiation has raised hopes of finding a cure for insulin-dependent diabetes mellitis. A study published in the Proceedings of the National Academy of Sciences last month has shown that in vitro, duct tissue from the human pancreas can be expanded and then reverted back into pancreatic stem cells. By culturing these cells under the correct conditions, they can be directed towards differentiating into islet cells. This is an important step forward in diabetic research as duct tissue is available in a much larger volume than that of islet cells. The American research team has shown that this process of ductal tissue differentiation can produce a 10-fold to 15-fold increase in insulin content. The cells also respond appropriately to increases in blood glucose volumes.

Insulin dependent diabetes affects an estimated half a million people in the United Kingdom. It results from an autoimmune destruction of insulin producing islet cells in the pancreas. Although it has been shown that islet cells taken from external sources can be successfully transplanted into humans and begin to produce insulin, there are not enough cells to produce viable tissue for transplantation on a large scale. This is why this new finding is such a breakthrough.

Dr Susan Bonner-Weir, who led the research team from Harvard Medical School, Boston, hopes that the technique may be able to produce large numbers of insulin producing cells to be used in B cell replacement therapy. "We're like alchemists changing lead into gold," she commented, referring to the transformation of otherwise discarded tissue into the valuable insulin producing cells. Although the islet generation is currently limited in quantity, the study raises the possibility that once the process is optimised, maintaining an in vitro cell line could produce significant amounts of new human islet tissue. Once enough cells are being produced, tissue transplantation is the next obvious step.