Policy puts future of stem cell tests in doubt
Vague language governs use of alternate methods
WASHINGTON -- With the active encouragement of the Bush administration, US scientists in the past year have developed several methods for creating embryonic stem cells without having to destroy human embryos.
But some who wish to test their alternatively derived cells have found themselves stymied by an unexpected barrier: President Bush's stem cell policy.
Under the 2001 policy, federal funds may not be used to study embryonic stem cells created after Aug. 9 of that year. It is based on the assumption that the only way to make the cells is by destroying human embryos -- which was true in 2001 but not any longer.
As a result, the National Institutes of Health recently refused to consider a grant application for what would have been the first federal study to compare several of the new, less politically contentious stem cell lines.
"This is not the way to make good health policy," said Robert Lanza, vice president for research and scientific development at Advanced Cell Technology in Worcester. Lanza submitted the study proposal with stem cell scientists from several major research labs.
Upcoming changes in the NIH's stem cell funding rules may help resolve that problem. But agency officials and others say the policy tangle is more complicated. Although Lanza's technique and other new approaches do not destroy embryos, they may run afoul of a longstanding congressional ban on studies that "harm" human embryos.
That vague language raises the question of how one would know whether an embryo had been harmed.
At the center of the debate is a new technique, pioneered by Advanced Cell Technology, that obtains stem cells from human embryos while leaving the embryos functionally intact. A single cell, called a blastomere, is removed from an eight-cell human embryo, then coaxed to multiply into a colony of stem cells in a dish.
Fertility doctors have been performing these blastomere biopsies for years to identify embryos that harbor genetic defects.
Because a single cell is representative of the entire embryo, doctors transfer to a mother-to-be's womb only those embryos whose plucked cells pass genetic muster. The loss of a single cell -- or even two -- at that stage is not known to cause developmental problems in children born by this procedure, doctors say.
In unpublished research, Advanced Cell Technology has made several colonies of stem cells this way, Lanza said. The seven-cell embryos developed normally and were frozen after the procedure a couple of days later, as embryos typically are until used by infertile couples.
The question is whether stem cells made this way are as versatile as those harvested from destroyed embryos. And what about stem cells created by other means, such as those of Anthony Atala, the Wake Forest University scientist who in January announced he had isolated embryonic stem cell equivalents from amniotic fluid?
To find out, Lanza joined with Atala and a team of others to compare stem cells made by various means. The group submitted a proposal to the NIH in February, then waited.
Eventually, the NIH told the team that it had referred the proposal to a different review group. Then, in a series of e-mails, the agency backed off further, first encouraging the applicants to drop Lanza's cells from the proposal and, finally, when the team refused to do so, informing them that the application was being sidelined indefinitely for "administrative review."
Story Landis, who heads the NIH's stem cell task force, said the main issue is Bush's Aug. 9, 2001, stem cell policy. It called upon the NIH to list all embryonic stem cell lines known as of that date and blocked funding for research on any cells but those on the list.
An executive order issued by Bush last month, when he vetoed legislation that would have expanded embryonic stem cell funding, could help resolve the problem, Landis said.
It instructs the NIH to rewrite the rules for funding stem cell research, with the emphasis not on whether the cells came from embryos but on whether any embryos were harmed.
It is unclear whether ACT's blastomere-derived lines, or those obtained from embryos by other means, might be deemed eligible. A 2005 report by President Bush's Council on
But the report noted that even if development proceeds normally, the child born may be different than one from an undisturbed embryo. It did not offer an opinion on whether such a shift would constitute harm.
The legal standard bans federal funding of research that subjects an embryo to more than "minimal" risk, although greater risk is allowed if the research is anticipated to benefit the embryo.