Stem cells' promise collides with politics
By Tina Hesman
Of the Post-Dispatch
04/21/2001
Joseph Zahner and Asutosh Sharda, former St. Louis University
professors, have a patent pending for a process that might allow them to
grow human liver tissue from ordinary skin cells.

The possibility that researchers someday could grow replacement parts
for people has turned stem cell research into one of the most exciting
fields of science.

These versatile cells might well be prodded into growing into new
human organs, replacing brain tissue to treat strokes, Alzheimer's and
Parkinson's diseases and even helping paralyzed people regain some
movement by healing injuries to the spinal cord.  Yet, stem cell research
also has become one of the most divisive and political areas in science
today.

The reason: Some of the most promising research so far centers on stem
cells that come from human embryos. And that has raised ethical
questions - especially among anti-abortion groups.

The stem cell debate could take center stage as soon this week in
Jefferson City as the Missouri House and Senate discuss pending life-
science funding bills.

And it already has become a hot-button issue in Washington, where the
National Institutes of Health has quietly canceled this week's planned
review of grants for human embryonic research pending a White House
review of its research guidelines.

At the heart of the issue is a type of powerful cell known as an
embryonic stem cell, which scientists say could revolutionize medicine.

The body's raw material
Stem cells are the raw material for building bodies. Embryonic stem cells
are taken from a tiny raspberry-shaped ball of cells called the blastocyst
about four days after sperm and egg collide at fertilization.

The cells have the ability to grow and divide virtually forever and can
become any type of cell in the body.

Embryonic stem cells "have the capacity to be coaxed into becoming
whatever kinds of cells you want them to be," said Dr. William Peck,
dean of the Washington University School of Medicine. "It's just
phenomenal what can be done."

In August, the NIH unveiled new guidelines that would allow scientists
to conduct research on stem cells derived from human embryos, as long
as the cells were made according to strict restrictions.

However, President George W. Bush has said that he does not support
research on human embryo or fetal tissue. Bush also expressed doubts
about the agency's interpretation of a law banning work on human
embryos.

Abortion opponents oppose research with stem cells from embryonic
tissue because they believe life begins at conception - when the sperm
fertilizes the egg.

Bush asked Health and Human Services Secretary Tommy Thompson to
review the guidelines and rule on the legal interpretation of the embryo
research ban. Thompson's ruling is expected this summer.

The NIH's Human Pluripotent Stem Cell Review Group was to have met
Wednesday to assess applications for federal money to do research on
embryonic cells. The meeting was postponed indefinitely until
Thompson decides whether the research can go forward, NIH officials
said.

The power of nature
The excitement over stem cells is not merely hype, researchers say.
"One of the reasons for being so optimistic is that (with embryonic
cells), you're not asking nature to do anything it doesn't normally do,"
said David Gottlieb, a developmental biologist at Washington
University. Gottlieb and his colleagues were the first to coax mouse
embryonic stem cells to make neurons and repair spinal cords in
paralyzed rats - a feat they hope to repeat with human cells.

The "uninteresting" appearance of the stem cells with their average-size
nucleus and small bodies belies their power, Gottlieb said.

"They're small, but they're smart," he said.

The cells are just waiting for the right signal to become any type of cell
in the body.

Stem cells grown in petri dishes spontaneously try out new fates, said
developmental biologist Doug Melton of Harvard University. The trick
is getting the cells to move down the pathway that scientists choose, he
said.

Researchers have made great strides in coaxing embryonic stem cells to
adopt a desired fate, but clinical applications are still years away -
largely because academic researchers have been barred from working
with embryonic cells, some scientists say.

Controversy and caution
Despite the enormous promise of the embryonic cells, only two groups
have submitted the necessary paperwork to show that they could
comply with NIH guidelines governing stem cell research. A third
application was submitted and then withdrawn.

But scientists say that shutting off money for embryonic stem cell
research would affect the entire scientific community - not just those
who apply for the money in an uncertain political climate.

"Scientists, like everyone else, follow the politics. They realize all this
research could be shut down," said Tim Leshan of the American Society
for Cell Biology.

Some of the caution may be due to the controversy regarding work with
embryo-derived tissue, said Dr. Dennis W. Choi, head of the
departments of neurology and neurological surgery at Washington
University. But it takes time to put together complicated grant proposals
and develop a project worthy of funding, he said.

"The green lights are just going on, and it takes awhile to gear up for
these," Choi said.

Federal restrictions on the type of material that can be used in
embryonic stem cell research have severely limited the supply of cells.
"There aren't a lot of stem cells out there that would be viable under the
guidelines," Leshan said.

The line of stem cells developed from aborted fetal tissue by Dr. John
Gearhart of Johns Hopkins University may qualify under the new
guidelines. But those stem cells isolated from discarded embryos by
James Thomson of the University of Wisconsin probably would not,
Leshan said.

Thomson's stem cells were taken from an embryo created for in vitro
fertilization, but the embryo was not frozen - a requirement under the
guidelines. Even if Thomson's cells met the requirements, patents on the
cells held by Geron Corp., of Menlo Park, Calif., make the cells
unavailable to most academic researchers, Melton said.

Adult stem cells don't work as well
The limitations on embryonic cell research have prompted many
scientists to search for adult stem cell alternatives.

Recent reports of stem cells isolated from fat, placenta and other sources
have been hailed by the news media and embryo-research foes. But
scientists in the stem cell field say that the potential of adult stem cells
can only be judged against the awesome power of embryonic cells - and
so far adult cells are not as flexible.

That is because adult cells have already started down a path that leads
them to a restricted number of developmental fates, while embryonic
cells have not made any decisions and can be pushed down any road.
Adult cells are more likely to have accumulated damage to their genetic
material and have not been shown to be truly reprogrammable.

"If stem cells from adult tissues worked as well, we wouldn't be having
this discussion," Peck said. In five to 10 years, the situation could
change, but right now, "they don't have the kind of potential that the
other cells have."

Bill Bell Jr. of the Post-Dispatch Jefferson City bureau contributed
information for this article.

Reporter Tina Hesman:
E-mail: [log in to unmask]
Phone: 314-862-2143

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