Embryo research: Scientists for the first time have turned ordinary skin cells into what appear to be embryonic stem cells - without having to use human eggs or make new human embryos in the process, as has always been required in the past, a Harvard research team has announced.
The technique uses laboratory-grown human embryonic stem cells, such as the ones that President Bush has already approved for use by federally funded researchers, to "reprogramme" the genes in a person's skin cell, turning that skin cell into an embryonic stem cell itself.
The approach, details of which are to be published this week in the journal Science but were made public on the journal's website yesterday, is still in an early stage of development.
Researcher Dr Kevin Eggan said: "I can't stress enough that this technology is not ready for prime time right now. It is not a replacement for those techniques that we already have for derivation of embryonic stem cells.
"There are lots of stumbling blocks still ahead," said B.D. Colen, a spokesman for Harvard.
But if further studies confirm its usefulness, the technique could offer a way around the heated social and religious debate that has for years overshadowed the field of human embryonic stem cell research.
Since the new stem cells in this technique are essentially rejuvenated versions of a person's own skin cells, the DNA in those new stem cells matches the DNA of the person who provided the skin cells. In theory, that means that any tissues grown from those newly-minted stem cells could be transplanted into the person to treat a disease without much risk that they would be rejected, because they would constitute an exact genetic match.
Until now, the only way to turn a person's ordinary cell into a "personalised" stem cell such as this was to turn that ordinary cell into an embryo first and later destroy the embryo to retrieve the new stem cells growing inside - a process widely known as "therapeutic cloning".
That prospect, like others in the promising arena of human embryonic stem cell research, has stirred strong emotions among those who believe that days-old human embryos should not be intentionally destroyed.
Embryonic stem cells are capable of becoming virtually any kind of cell or tissue and are being intensely studied around the world as the core of a newly emerging field of regenerative medicine, in which researchers hope to grow new tissues to revitalize ailing organs.
Although embryonic stem cells have never been tested in humans, some researchers expect human clinical trials to begin within a year. Researchers caution that like many other nascent therapies that initially seemed promising, stem cells may never live up to their promise.
The new work could have an impact on Capitol Hill, where the Senate is poised to vote on legislation - already passed by the House - that would loosen Bush's restrictions on human embryonic research.