Monday July 16 2:21 PM ET
"Experts Say Stem Cells Promise Medical Revolution"
|In-depth coverage about |
Human Stem Cell Research
Related News Stories|
|·||Uncertainty Is Thwarting Stem Cell Researchers - Los Angeles Times (Jul 16, 2001)|
|·||U.S. Stem Cell Researcher Defects to Britain - Reuters (Jul 16, 2001)|
|·||Bush faces difficult decision on funding for stem cell research - AFP (Jul 15, 2001)|
|·||Bush 'Agonizing' Over Funding of Embryo Research - Washington Post (Jul 15, 2001)|
|·||Nancy Reagan Backs Research on Stem Cells - Washington Post (Jul 14, 2001)|
Opinion & Editorials|
|·||Stem Cell Genie - NY Times (registration req'd) (Jul 16, 2001)|
|·||The Embryo Taboos - NY Times (registration req'd) (Jul 15, 2001)|
|·||Getting a grip on stem cell research - Boston Globe (Jul 15, 2001)|
Related Web Sites|
|·||Stem Cells: A Primer - covers what pluripotent and stem cells are, how they are derived, why they are important to science and for advances in health care, as well as what adult stem cells are. From the National Institutes of Health.|
|·||Stem Cell Research and Applications - information from the American Association for the Advancement of Science.|
|·||Why Files Guide to Stem Cells - introduction covering stem cell biology and research issues.|
|·||Bioethics Internet Project - includes Bioethics for Beginners. From the University of Pennsylvania.|
|·||National Bioethics Advisory Commission|
|·||What are stem cells and what are they used for? - Howstuffworks (Jul 11, 2001)|
|·||Stem cells: Medicine's new frontier - MayoClinic.com (Jul 11, 2001)|
|·||The cutting blob of ethical politics - The Economist (Jul 5, 2001)|
|·||Cloning regulation jurisdiction raises new questions - NPR (Jul 13, 2001)|
|·||Britain allows cloning of human embryos for research - CBC (Jan 23, 2001)|
|·||Human Cell Breakthrough|
|·||Yahoo! News Search|
|·||New Scientist: Stem cells|
|·||Mayo Clinic Health Oasis|
Related Full Coverage|
Experts Say Stem Cells Promise Medical Revolution
By Will Dunham
WASHINGTON (Reuters) - A revolution is coming in medicine,
and versatile human cells called stem cells -- some formed just
days after a sperm cell fertilizes an egg and others harbored
inside the bodies of children and adults -- promise to lead the
way, researchers say.
Stem cells offer the potential to provide treatments for a
fantastic array of diseases affecting millions of people around
the world. But it remains mere potential.
One reason is that much more work needs to be done to gain
a fuller understanding of the biology of stem cells and perfect
therapies that could be used to treat people.
Another reason is money. President Bush (news - web sites) is mulling whether
to allow federal funds to be used to support research involving
stem cells harvested from human embryos.
"I think it will be a revolution, a paradigm shift, in how
we treat disease," said Helen Blau, who chairs the department
of molecular pharmacology at Stanford University School of
Medicine. "You enlist the body's own resources to fight its own
disease. That's what's so attractive to me about it."
Doctors currently use drugs and surgery to try to shore up
or treat tissues and organs damaged by disease. But because
stem cells can transform themselves into many other cell types
with the right prompting, doctors may be able to replace the
damaged tissues and organs to restore healthy function.
So for people with Parkinson's disease (news - web sites), injecting stem
cells into the area of the brain that controls muscle movement,
where the ailment kills nerve cells, might regenerate the
neurons and reverse the disease. For diabetics, the stem cells
might regenerate certain cells in the pancreas so the body can
make its own insulin rather than relying on shots of it.
"They truly do have the ability to form anything in the
body," said University of Wisconsin researcher Dr. James
Thomson, who in 1998 became the first to isolate human
embryonic stem cells.
Experts said stem cells also could be used to treat:
Alzheimer's disease (news - web sites); stroke; heart attack; multiple sclerosis;
blood, bone and bone marrow ailments; severe burns by providing
skin grafts; spinal cord injuries; and cancer patients who have
lost cells and tissue to radiation and chemotherapy.
"There's a lot of science that still needs to be done
before we have good treatments. That's not to say that we
won't. In three to five years we may have early treatments
using these stem cells," said UCLA researcher Dr. Marc Hedrick,
who found adult stem cells in fat removed in liposuction.
ADULT AND EMBRYONIC STEM CELLS
The current political debate focuses on embryonic stem
cells versus so-called adult stem cells, a misnomer because
they are also found in children.
About five days after fertilization, the human embryo
becomes a blastocyst -- a hollow sphere of about 100 cells.
Cells in its outer layer go on to form the placenta and other
organs needed to support fetal development in the uterus. The
inner cells go on to form virtually all of the tissues of the
body. These are the embryonic stem cells used in research.
Adult stem cells are harbored in the bodies of children and
adults. They are more specialized than embryonic stem cells and
give rise to specific cell types. For example, certain stem
cells in the bone marrow spawn red blood cells, white blood
cells and blood platelets.
Experts previously believed adult cells did not offer the
promise of their embryonic cousins due to this lack of
versatility, but recent research suggests they can turn into
many more cell types than once believed possible.
Dr. Neil Theise of New York University Medical Center, who
has shown that adult stem cells may be as flexible as the
embryonic ones, cited strengths and weaknesses for each.
Theise said the advantages of embryonic stem cells include
two important qualities: they can become almost anything in the
body, and they can be grown in culture in an unlimited
quantity. The disadvantages are that a patient's immune system
might reject transplants of embryonic stem cells just as some
organ transplants are rejected, and that runaway growth of
embryonic stem cells could produce tumors, Theise said.
A key advantage of adult stem cells is that because they
would be taken from the very patient who would receive them in
treatment, there are no rejection issues, Theise said.
Disadvantages include: questions about whether they can
transform themselves as readily as embryonic stem cells;
difficulty in growing adult cells in culture at the quantity
needed to facilitate transplants; and worry that years of
exposure to toxins, radiation and DNA replicating errors could
leave them with genetic abnormalities, experts said.
THE MOST CRUDE WAY TO USE THESE CELLS
Researchers said using transplants of stem cells to
regenerate tissue and organs -- essentially injecting the stem
cells into the area of damage to achieve cellular regeneration
-- may be one of the first therapeutic uses.
"It's the most crude way to use these cells. But
theoretically that could work. But I think there are going to
be more refined, subtle approaches," Theise said.
Thomson said one important use for embryonic stem cells
would be in the area of drug development.
Researchers would be able to test a drug's therapeutic
effects and toxic side effects in human tissue without using a
laboratory animal as a proxy.
"For example ... heart cells in humans and mice are very
different," Thomson said. "And there's been a whole series of
drugs that we tested on mice that got to (human) clinical
trials that ended up being toxic to the human heart and that's
because it was tested on mice and not humans."
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