Home' Technology Review : May June 2006 Contents TECHNOLOGY REVIEW /
FEATURE STORY 63
As American scientists gear up for the new race toward
nuclear transfer, they face many of the same hurdles that
stranded most of them in the starting block two years ago.
Hwang had huge sums of money from the Korean govern-
ment, an adoring public, and an enormous, albeit ethically
unsound, supply of human eggs. U.S. scientists face intense
public scrutiny, an administration opposed to embryonic-
stem-cell research, and a continuous struggle to get fund-
ing from private investors.
In 2001, President Bush limited federal funding for
embryonic-stem-cell research to work involving a small
number of cell lines already in existence. That policy has
exerted a disastrously chilling e ect on the eld. Scientists
who wish to do research on newly derived embryonic-stem-
cell lines or to derive new lines themselves---as is necessary
in nuclear transfer---must nd private sources of funding.
Scientists and university administrators also face the
arduous task of separating all publicly and privately funded
research. "It means everyone is dragging 10-pound weights
on their feet," says Greg Simon, president of FasterCures, a
Washington, DC--based advocacy group that aims to speed
development of novel therapies. "We re spending a lot of
wasted time separating government money from private
money when we should be spending time doing research."
The federal blockade also means that the National Insti-
tutes of Health, the nation s largest biomedical-research
institute, has forsaken its standard regulatory role, leav-
ing many scientists operating in a vacuum. The National
Academy of Sciences has tried to pick up some of the slack,
publishing a nonbinding set of guidelines for stem cell
research in 2005 and creating a stem cell research over-
sight committee earlier this year.
Many state governments have felt compelled to step
in, both regulating and providing funding for stem cell
research. So far, California, Connecticut, Massachusetts,
and New Jersey have passed laws that permit embryonic-
stem-cell research, including work on cloned embryos.
Arkansas, Indiana, Iowa, Michigan, North Dakota, and
South Dakota prohibit research on cloned embryos.
In addition, California, Connecticut, and New Jersey
have all earmarked state funds to support stem cell research
not funded by the federal government. The California initia-
tive, by far the biggest at $3 billion, has encountered pitfalls
at every turn, demonstrating the di culties that arise when
states get into the research-funding business. The Califor-
nia Institute for Regenerative Medicine, the oversight entity
created by the state s Proposition 71, has grappled with
accusations of con icts of interest among those who deter-
mine the distribution of funds and with controversies over
how the state will reap the nancial bene ts of stem cell
research---a promise that was part of the proposition.
Almost all embryonic-stem-cell research in the United
States faces funding obstacles and ethical objections, but
because nuclear transfer is the most contentious topic in
the eld---it involves not only the destruction but also the
creation of embryos speci cally for research---scientists and
universities planning nuclear-transfer programs are extra-
cautious. "The spotlight is on anyone doing this kind of
research," says Lanza. For example, Massachusetts law
mandates criminal penalties for people who violate laws
governing egg and embryo procurement. "If we slip up any-
where, we ll be cr uci ed," Lanza says.
One of the biggest obstacles
to stem cell--based therapies is
the possibility of immune rejec-
tion, as can happen with donor
kidneys. Patient-matched stem
cells---derived from a patient-
donated skin cell---could pres-
ent a way around this problem.
But as researchers have come
to believe that cloning stem
cells may be too inefficient for
broad use, they have begun
developing other ways to over-
come immune rejection.
Rather than creating stem
cell lines for every patient who
needs them, says Stephen
Minger, a stem cell scientist
at King s College London,
we might do better to create
1,000 stem cell lines repre-
senting the most common
immune profiles in the popu-
lation. "You wouldn t get a per-
fect match for everyone...but
you would be close, and you
might only need mild immuno-
suppression," he says.
Scientists are also develop-
ing ways to use stem cells to
deceive the immune system.
"If you can knock out [immune
response], it s possible you
can have cells sneak under
the radar," says Tim Kamp, a
stem cell scientist at the Uni-
versity of Wisconsin--Madison.
Preliminary research suggests
that turning stem cells into a
type of immune cell known as
a dendritic cell can trick the
host s immune system into ac-
cepting other, related cells. If
scientists made both immune
cells and whatever cell type
was needed for therapy from
the same lines of stem cells,
they might be able to inject
both cell types into a patient
without an immune response.
In some cases, doctors may
not need to worry about im-
mune rejection. "We re starting
to recognize that stem cells
may be better tolerated by the
immune system in some areas
of the body than we expected,"
says Evan Snyder, a neurolo-
gist at the Burnham Institute
in La Jolla, CA. "Embryonic
stem cells seem to be toler-
ated in the brain, even without
Geron, a California-based
biotechnology company de-
therapies, is taking advantage
of this fact to develop new
treatments for spinal-cord
injury. Scientists have spurred
injured rats to walk again after
injections of neural precursor
cells derived from embryonic
stem cells; Geron is seeking
permission to start human
clinical trials of a related pro-
cedure next year.
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