New Potential for Stem Cells
Suggested
Findings of Three Studies May Affect Treatment of
Diabetes, Alzheimer's Disease
Date accessed: 08 May 2001
By Rick Weiss Three research reports provide evidence that cells from human embryos and
fetuses have the potential to cure ailments affecting millions of Americans -- a
conclusion that is likely to intensify an already heated debate over the ethics
of human embryo cell research. In one report, old rats performed better on a test of memory and learning
after scientists injected brain cells from aborted human fetuses into the
rodents' age-addled brains. It's the first indication that such transplants can
prompt cognitive improvements, and it hints at a treatment for Alzheimer's
disease and other forms of dementia. In a second report, scientists coaxed embryo cells in laboratory dishes to
become the specialized parts of the pancreas responsible for regulating blood
sugar levels -- an advance that could lead to an effective treatment for many of
the nation's 16 million diabetics. A third study demonstrates that in mice, at least, cloned embryos contain
bona fide "embryonic stem cells," capable of growing into virtually
every kind of adult tissue. That suggests people may someday want to clone their
cells -- not to make full-grown duplicates of themselves but to create embryos
from which precious stem cells could be retrieved. Those stem cells could be grown into replacement tissues for transplantation
into the patient, and they would not be rejected because they would match the
patient's genes exactly. The three studies, released by scientific journals yesterday, add a sense of
urgency to the escalating political and ethical controversy surrounding human
cloning and embryonic stem cell research. Congress is poised to consider several anti-cloning bills -- including one
introduced yesterday by Sen. Sam Brownback (R-Kan.) and Rep. Dave Weldon (R-Fla.)
-- some of which could end up criminalizing not only human cloning, but also
cloning of human embryos. A plan by the National Institutes of Health to fund
research on human embryo cells has been put on hold pending a Bush
administration review of the work's legal and ethical implications. Critics find the work offensive because stem cells are typically retrieved
from aborted fetuses or human embryos slated for destruction at fertility
clinics. By contrast, Bush and others support work on what are called adult stem
cells, which have not shown the same range of potential as embryo and fetal
cells. The new report do not suggest cures based on cloning or embryo cells are
imminent; indeed, human testing may be many years away. But several scientists
said yesterday the studies solidify the argument for federal support of human
embryo cell research. "You need to do this kind of research to get to the goal of helping
people," said Robert Goldstein, chief scientific officer of the Juvenile
Diabetes Research Foundation in New York. "These kinds of results have not
been achieved with adult stem cells. And we'd really like to see this helping
kids." In the most dramatic, but least well documented, of yesterday's reports,
Kiminobu Sugaya and his colleagues at the University of Illinois injected
"neural stem cells" from aborted human fetuses into 24-month-old rats,
which are equivalent in age to people about 80 years old. The cells developed
into neurons and other brain cells, the team says in NeuroReport, a little known
online journal. When tested for their ability to learn and remember the location of a movable
submerged platform in a tub of milky water, the rats scored better than they had
before getting the transplants, on average doing as well as young adult rats.
Sugaya said he thought the new cells provided added brainpower and also secreted
natural chemicals that nurtured older brain cells. Several neuroscientists gave guarded assessments, saying the report, though
promising, lacked critical details. "I'd be really shocked because it's asking a lot for this to happen in
old brains," said Stanford University's Irving Weissman, co-founder of
StemCells Inc. of Palo Alto, Calif., which hopes to commercialize stem cell
cures. "But this is a new field and I'm shocked a lot these days, so who
knows?" By contrast, many scientists were enthusiastic about the report by NIH
scientist Ron McKay in today's issue of Science. McKay's group turned mouse
embryo stem cells into complex, many-celled structures that look and act like
islets of Langerhans -- the pancreatic structures that detect high blood sugar
levels and respond by secreting insulin. The work suggests that similar clusters, grown from human embryo cells, could
be transplanted into children with type I diabetes, who lack functioning islet
cells. The islets worked properly when transplanted into diabetic mice, albeit
at a level too low to normalize the animals' blood sugar. McKay and others said
they think the cells will work better when allowed to mature. "This work is about the most exciting in the diabetes field in the last
decade," said Doug Melton, Harvard's chairman of molecular and cell
biology. "You don't have to be a rocket scientist to say, 'Let's try this
with human ES cells and see what happens.' " In the third study, Teruhiko Wakayama and colleagues showed that when mice
are cloned, the resulting embryos contain true stem cells that can be turned
into all the major cell and tissue types. In one effort, the team turned stem
cells into dopamine-secreting neurons, the type of brain cells that degenerate
in Parkinson's disease. A long-term goal is for Parkinson's patients to grow compatible replacement
neurons from their own cloned embryos, said Anthony Perry, a co-author of the
report in Science. Perry and Wakayama recently left Rockefeller University for
Advanced Cell Technology in Worcester, Mass.
Washington Post Staff Writer
Friday, April 27, 2001; Page A02
Categories: 31. Stem Cells, 33. Cloning