Future of Stem Cell Tests May Hang on Defining Embryo Harm
By Rick Weiss
Washington Post Staff Writer
Sunday, July 29, 2007; Page A08
With the active encouragement of the Bush administration, U.S.
scientists in the past year have developed several methods for
creating embryonic stem cells without having to destroy human embryos.
But some who now wish to test their alternatively derived cells have
found themselves stymied by an unexpected barrier: President Bush's
stem cell policy.
The 2001 policy says that 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 -- a truism 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,
the frustrated vice president for research and scientific development
at Advanced Cell Technology (ACT) in Worcester, Mass. Lanza submitted
the study proposal with stem cell experts from several major research
labs.
Upcoming changes in the NIH's stem cell funding rules may eventually
help resolve that problem. But agency officials and others say the
policy tangle is more complicated than that. Although Lanza's
technique and other new approaches do not destroy embryos, they may
run afoul of a long-standing congressional ban on studies that "harm"
human embryos.
That vague language raises the perplexing question of how one would
know whether an embryo had been harmed.
At the center of the debate is a new technique, pioneered by ACT,
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. Since a single
cell is representative of the entire embryo, doctors transfer to a
mother-to-be'
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In unpublished research, ACT has made several colonies of stem cells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. And waited.
Charo said that she is uncomfortable with both ideas, because
they "suggest the embryo has an active interest in being born" -- a
philosophical notion that imputes a level of personhood to embryos
that many stem cell supporters do not accept.
Landis, of the NIH, would not say how the agency will decide which
cell lines involve risks small enough to be eligible for funding, nor
would she say what role, if any, the White House will have in those
decisions.
Agency insiders, however, said the NIH is likely to convene workshops
and fund animal tests to study the degree of harm various procedures
pose to embryos -- a meticulous approach that strengthens suspicions
among research proponents that real stem cell policy changes are
unlikely while Bush is in office.
"I think they're trying to ride the clock out," Lanza said.
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 make a list of all embryonic stem cell lines known as of that
date and blocked funding for research on any cells but those on the
list.
A Funding Hurdle
Continued limits on federal funding of embryonic stem cell research,
spelled out in President Bush's June 20 executive order, ban funding
for new approaches that do not destroy embryos if there is even a
chance that those embryos might face more than minimal harm.
"Currently, there are no cell lines derived from single blastomeres
listed on the stem cell registry as eligible for funding," Landis
said.
Sean Tipton, president of the Coalition for the Advancement of
Medical Research, a stem cell research advocacy group, said the
policy amounts to a Catch-22.
"On the one hand, they're saying, 'Find this out,' " Tipton said,
referring to the Bush administration'
to find ways to make and study stem cells without destroying
embryos. "On the other hand, they're saying, 'You're not allowed to
do the research to answer these questions.' "
A little-noted executive order issued by Bush last month, when he
vetoed legislation that would have expanded embryonic stem cell
funding, could eventually 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.
Bush, in an interview this week with The Washington Post, reiterated
his belief that "there are ways to develop stem cell lines without
the destruction of human life. There's a myriad of ways to advance
good science without crossing an ethical line."
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 Bioethics concluded that
the blastomere approach (still theoretical at that time) "might be
eligible for funding" under the do-no-harm-to-
the report raises a concern.
"[E]ven if development proceeds in a healthy manner, it may be that
the child born is somehow a different child than the one that would
have resulted from an undisturbed embryo," the report said, without
opining on whether such a shift of fate would constitute harm.
The legal standard of allowable harm to an embryo is spelled out in
1995 congressional language and is reiterated in Bush's June 2007
executive order. It 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.
For now, Lanza has suggested limiting his technique to embryos that
are already due to be biopsied at a fertility clinic. The plucked
cell could divide for a day, providing enough cells for both the
genetic testing and to start a line of stem cells. That way the
embryo would not be subjected to any new or additional risk.
Still, for funding, that risk would have to be "minimal" -- a
standard open to "interpretative discretion," said R. Alta Charo, a
professor of law and bioethics at the University of Wisconsin at
Madison.
From one perspective, she said, fertility clinic testing can be seen
as a risk because if the embryo "fails" its genetic test, it will not
be given an opportunity to grow into a child.
But some couples who know they harbor genes that can cause a fatal
childhood disease might never risk having children unless they could
test their embryos and select those not affected. For those embryos,
the test poses an opportunity for life that would not otherwise exist.
http://www.washingt
dyn/content/
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
____________________________________________
«¤»¥«¤»§«¤»¥«¤»§«¤»¥«¤»«¤»¥«¤»§«¤»¥«¤»§«¤»¥«
¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch format to Traditional
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___
