Democrats have said
they'll use their new clout in Congress to lift
or at least loosen restrictions on federal funding
for embryonic stem-cell research. But readily available
treatments using the stem cells, if they prove
effective, are years away, says a stem-cell expert
at the University of Utah.
 Deseret Morning News Graphic "We have made
progress in the past couple of years, but it's going
to continue to be slow progress. We don't have profound
findings that have made it all clear," said
Dr. Linda Kelley, director of the cell-therapy facility
at the U. and an associate professor of medicine.
Stems cells are unspecialized cells that can replicate themselves for a long
time through cell division. Under specific conditions, they can be induced to
become cells with special functions. Scientists want to learn how those cells
remain unspecialized and self-renewing. And they say if they decode the signals
that tell cells what to become, it may lead to treatments for diseases and injuries.
Two types of human stem cells are being investigated worldwide — embryonic
stem cells donated from unused fertilized eggs in fertility clinics, and adult
stem cells. In 2001, President Bush limited federal funding for human embryonic
stem-cell (hESC) research to that involving about a dozen already established
hESC lines.
He didn't ban the research, as many believe but rather "shifted who pays
for it" to biotech companies, endowments and state governments, Kelley said.
The Democrats have said that loosening the restrictions and expanding federal
funding of the research is a priority they plan to deal with in the first 100
hours of the new session of Congress. A number of Republicans also support the
move.
So does the public, according to two surveys released this week. The Civil Society
Institute said Thursday that two-thirds of Americans want to see expanded federal
support for stem-cell research. And 60 percent want Congress to override any
presidential veto, deemed likely because Bush used his first-ever veto to turn
down an earlier bill easing the restrictions.
The institute said that "the steadily growing and bipartisan support for
stem-cell research now includes two-thirds of American adults — including
majorities of Republicans, Independents, Roman Catholics and evangelical Christians."
An Associated Press-AOL News poll said 56 percent of adults favor easing the
restrictions.
Supporters of the research have a long list of conditions that they believe stem
cells might cure, from Parkinson's to kidney failure, diabetes and traumatic
spinal-cord injury,
Still, anyone hoping for an immediate cure is apt to find it's a long wait, Kelley
said.
Adult stem cell are used more often in clinical trials than embryonic cells.
They have been injected into the hearts of patients with heart disease to see
if they are an effective treatment. A specific kind of bone marrow stem cell
is being tested to see if it helps kidney patients with acute renal failure.
Another clinical trial is trying to treat an "orphan" neurodegenerative
disease with neuro stem cells. Recently, Oregon doctors injected stem cells to
try to stop seizures, while doctors elsewhere hope stem cells will restore vision
to a man who lost it more than 20 years ago.
Results of most clinical trials are not yet available. And it will likely be
years before any resulting treatment is readily available, experts agree. But
the number of clinical trials being proposed continues to grow, and the FDA is
approving more of them, Kelley said, so "more patients are starting to get
stem cells as a possible treatment."
Embryonic stem-cell research is "going on at a rapid speed," Kelley
said, describing "a lot of progress and still a lot of hurdles to overcome."
Many researchers believe it is possible to take immature hESC and, in the lab,
turn them into pancreatic islet cells or kidney cells or heart cells, for instance.
Researchers are still trying to learn the right signals to make them become specific
cells, although the National Institutes of Health reports some "recipes" have
been developed.
NIH lists advantages and disadvantages for the types of stem cells: While embryonic
cells can become all cell types, adult stem cells are limited to changing into
different cell types of their tissue of origin, although there's emerging evidence
they have more flexibility than originally believed.
Embryonic cells can be grown and expanded in culture, but adult stem cells are
rare, and the methods for expanding their numbers in culture haven't yet panned
out. That's important, NIH says, because of the large number of cells needed
for therapies. Adult stem cells may have a large advantage in that those cells
taken from an individual would not be rejected by his immune system, which could
be a problem with embryonic stem cells derived from a genetically different background.
Researchers hope to get around that by learning how to genetically engineer cells
to make them identical to an individual's. Unfortunately, Kelley said, early
claims of success turned out to be fraudulent.
Another problem: When researchers have been able to get a stem cell to turn into
the type of cell they want and have injected the cells into animals, malignant
germ-cell tumors have resulted.
Bone-marrow transplant is the only use of stem cells now an actual standard of
care, Kelley said. It's the gold standard to cure leukemia and lymphoma. But
it has taken more than 50 years of research and fine-tuning.
Other considerations include long-term effects, how many treatments might be
needed, cost-effectiveness and who pays for it.
"My sense is that scientists and clinicians think research should go on
with both (adult and embryonic stem cells)," Kelley said. "It's not
going to be a single magic bullet. Maybe adults cells will work in certain cases,
and you have to have embryonic stem cells to have an effective treatment for
something else. There's great interest in continuing to pursue both avenues."
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