NEW YORK - In a leap forward for stem cell research, three independent teams of scientists reported Wednesday that they had produced the equivalent of embryonic stem cells in mice using skin cells without the controversial destruction of embryos.
If the same could be done with human skin cells - a big if - the procedure could lead to breakthrough medical treatments without the ethical and political debates surrounding the use of embryos.
"I think it's one of the most exciting things that has come out about embryonic stem cells, period," said researcher Dr. Asa Abeliovich of Columbia University in New York, who didn't participate in the work. "It's very convincing that it's real."
But he and others cautioned that it would take further study to see whether this scientific advance could be harnessed for creating new human therapies. The procedure used to get the mouse skin cells to mimic embryonic stem cells wouldn't be suitable. And it's not known whether the mouse results can be reproduced with human cells.
"We have a long way to go," said John Gearhart of Johns Hopkins University, a stem cell researcher who also wasn't involved in the new work.
In any case, scientists said, the advance does not mean that research that involves getting stem cells from human embryos should be abandoned.
"We simply don't know which approach ... will work the best," said researcher Konrad Hochedlinger of the Harvard Stem Cell Institute, who led one of the three teams.
Embryonic stem cells are prized because they can develop into all types of tissue. Experts think they might be used for transplant therapies in people who are paralyzed or have illnesses ranging from diabetes to Parkinson's disease.
Harvesting human embryonic stem cells involves destroying human embryos, to which many people object.
Scientists have long hoped to find a way to reprogram ordinary body cells to act like stem cells, avoiding the use of embryos. The new mouse studies seem to have accomplished that. Previous experiments have generally involved tampering with an embryo or egg.
At a press conference Wednesday, Hochedlinger and a member of a second team said their work was not an attempt to evade the ethical objections to embryo destruction. They said the goal was to learn how cell reprogramming works.
But a prominent critic of embryonic stem cell research welcomed the new work on ethical terms.
"This is what we were looking for, people to explore because it may provide all the advantages of embryonic stem cells without the moral problem," said Richard Doerflinger, deputy director of pro-life activities for the U.S. Conference of Catholic Bishops. "So I'm very encouraged."