The research, published in the June 2007 issue of the journal Cell Proliferation, could eventually lead to a cure for type 1 diabetes and highlights that umbilical cord blood stem cells, which in future could be stored from birth, could provide an ethically favourable alternative to stem cells harvested from human embryos.
'This discovery tells us that we have the potential to produce insulin from adult stem cells to help people with diabetes,' said Dr Randall Urban of the University of Texas Medical Branch at Galveston, who lead the study, which has been heralded as baseline work for future research into whole organ regeneration.
Despite overall optimism, Dr Urban stresses that the research is at a very early stage, 'It doesn't prove that we're going to be able to do this in people - it's just the first step up the rung of the ladder'.
In a laboratory dish, the researchers used a complex cocktail of signals, normally produced by the embryonic mouse pancreas, to instruct the human stem cells to develop, or 'differentiate', into islet-like cells similar to those which produce insulin in the human pancreas.
People affected by type 1 diabetes, whose insulin-producing cells have been destroyed, have to inject themselves several times daily with insulin to maintain normal glucose levels in their blood. It is hoped that the transplantation of working copies of the islet-like cells, derived from human stem cells, could in future lead to a cure for these patients.
However, some experts are more sceptical, 'In the past, these claims have been rather unconvincing', said Dr Rudolph Jaenisch , an expert from the Whitehead Institute in Cambridge, Massachusetts, in a telephone interview with Reuters. His view is that previous attempts to differentiate insulin-producing cells from human stem cells have ultimately proved fruitless: either yielding only small amounts of insulin or in fact later proving to be mistaken.
The US Company Geron recently announced it had successfully differentiated human embryonic stem cells into insulin-producing cells.