Stem cell breakthrough turns out to be a lot less than first advertised
Carl T. Hall, Chronicle Science Writer
Sunday, September 24, 2006
Some fuzzy statements to the press have landed the stem cell field back in the soup just when researchers appeared to be winning new public acceptance.
Missouri polls signal a probable win in November for a pro-research ballot initiative. Stem cell advocacy has become a wedge issue all over the country for Democrats angling to retake Congress. In California, the Proposition 71 effort finally has some real money to throw around after Gov. Arnold Schwarzenegger loaned $150 million to get the lawsuit-entangled program running.
Then came word that a biotech company, Advanced Cell Technology, which has moved its headquarters from Massachusetts to Alameda to take advantage of Prop. 71's $3 billion grant program, had produced stem cell lines a new way, by manipulating single cells, known as blastomeres, taken from embryos at the very early stage when they typically have only eight cells.
This was big news all over the world because it meant that human embryonic stem cells might be produced without destroying embryos.
Single blastomeres are taken all the time from eight-cell embryos in order to diagnose disease genes prior to in vitro fertilization, a technique known as pre-implantation genetic diagnosis. Even with only seven cells remaining, the biopsied embryos appear to be capable of developing normally once they are implanted in the womb.
Scientists say stem cells made this new way could have some interesting properties. But the seeming ethics breakthrough isn't so clear-cut.
Advanced Cell Technology's scientists were trying to work out a nondestructive recipe for producing stem cells, but the initial stage of the work still required the sacrifice of some embryos. In fact, the company used 91 cells from 16 donated embryos to get the first two stem cell lines. None 0f those embryos, of course, could be implanted afterward -- all were destroyed.