Blow to stem cell research
2006-11-23 12:50
Paris - In a fresh blow to stem cell research, a US biotech firm that three months ago declared it could create embryonic stem cells without harming embryos has taken a major step back from this claim.
Advanced Cell Technology (ACT), a biotech firm in California, runs a corrected version of its research in Thursday's issue of the British journal Nature, which ran the original paper on August 24.
In August, ACT said it had unlocked a way to grow embryonic stem cells from a single cell from an eight-celled embryo.
The cell was extracted using a biopsy technique similar to that already used for taking tissue from a foetus so that it can be checked for rare inherited disorders.
The technique "maintains (the) developmental potential of (the) embryo", an ACT press release accompanying the August paper said. The approach "does not harm embryos".
That press release also quoted ACT's boss and the chairperson of its ethics advisory board as saying the success offered a way out of the impasse in the US concerning stem cells.
ACT's claim - which caused the company's stock to quadruple immediately - was seen by some as a welcome boost for stem cell research, battered by the unmasking of South Korean scientist Hwang Woo-Suk as a fraud.
Angry accusations of hype
But it also ran into angry accusations of hype from other scientists. They said ACT had put forward no evidence that the embryos from which the genetic material had been plucked would have developed normally.
In its published correction in Nature, ACT said that "to minimise the number of embryos used, we removed multiple cells from each embryo", which had comprised between eight and 10 cells.
"None of the biopsied embryos were allowed to develop in culture," it said, implicitly admitting the embryos had not been tested to see if they would, or even could, survive.
Even so, ACT argued, this did not detract from its "central finding" that lines of embryonic stem cells could be grown from a single blastomere, or cluster of cells.
Stem cells are immature cells that grow into various tissues. The most exciting of these types are so-called pluripotent stem cells that are garnered from embryos at a very early stage and develop into almost any kind of tissue.
The dream of scientists - and of investors who have pumped hundreds of millions of dollars into the research - is to coax embryonic stem cells into become lab-dish replacements for cells that have been damaged or destroyed by cancer, Alzheimer's, Parkinson's and other diseases.
So far, the quest has proven to be a greater technical challenge than was thought and it has been rocked by ethical debate, especially in the United States, and accusations that claims are overblown.
US President George W Bush has invoked a veto over the use of federal funds for embryonic stem cell research.
The storm is the latest to dog stem cell research and to fuel charges that the top scientific journals are failing to thoroughly scrutinise claims of breakthroughs.