I think this article offers much hope without the usual media hype.
According to Dr. McKay - clinical trials with embryonic stem cells may
be possible in 4 years. Better than the earlier predictions of 10 years
or more.
I would add - if the most promising research is not banned, unfunded,
impeded, limited, or slowed by our government.
Linda
FROM: The New York Times
June 21, 2002, Friday, Late Edition - Final
Section A; Page 18; Column 4; National Desk
HEADLINE: Progress Is Reported on Parkinson's Disease
BYLINE: By NICHOLAS WADE
Scientists working with human embryonic stem cells have converted them
into
the type of brain cell that is lost in Parkinson's disease, and have
shown that
the equivalent cells in mice alleviate Parkinson-like symptoms in
rodents.
"What we are showing here is that we absolutely, definitely have the
right
cell," said Dr. Ron McKay, a stem cell biologist who works at the
National
Institutes of Health.
The cells produce a neuron-to-neuron signalling chemical called
dopamine.
The loss of dopamine is believed to cause many of the symptoms of
Parkinson's
disease. Dr. McKay hopes that the cells he has developed will one day be
used to
treat the disease, after he has spent two years testing how they work in
monkeys. Indeed a surgeon could put them in patients quite quickly "but
they
wouldn't know what they have done," Dr. McKay said.
The need for caution is apparent in his own experiments, in which he
injected
the dopamine-producing mouse cells into the brains of rats. The
dopamine-producing cells on one side of the rats brains had previously
been
destroyed with a special chemical. So the rats, suffering Parkinsons-like
effects on one side of their brains, tended to move in circles.
In the article published today in Nature, Dr. McKay and his colleagues
describe how they injected their dopamine-producing cells into the
damaged sides
of the rat brains. The cells wired themselves up to other cells in the
brain and
behaved just like dopamine-making cells, helping the rat's walking
behavior.
Unfortunately the cells produced too much dopamine and instead of
straightening the rats out made some of them walk clockwise instead of
counter-clockwise.
Dopamine-making cells obtained from aborted fetuses have also been
used to
treat Parkinson's disease, so far with minor effects.
Dr. Gerald D. Fischbach, a leading neurobiologist at Columbia
University,
said that the new cell therapy approach to Parkinson's was "extremely
promising." The previous studies with fetal cells had shown "a modest
improvement in rigidity and paucity of movement," and Dr. McKay's
approach held
the promise of a purer population of cells, Dr. Fischbach said.
Dr. McKay and others have shown previously that embryonic cells could
be
converted into dopamine-making cells, but this is the first time the
cells have
been implanted in an animal, with evidence of a functional effect. "So it
a step
in the right direction," said Dr. Fred Gage, a brain cell expert at the
Salk
Institute.
Critics of cell therapy have warned that whatever unknown cause kills
a
Parkinson's patient's dopamine-producing cells in the first place may
also
obliterate implanted cells, however well they work.
But Dr. Sean Morrison, a stem cell biologist at the University of
Michigan,
said there was evidence that 90 percent of the risk of Parkinson's comes
from an
environmental source, perhaps a one-time exposure to some unknown toxin.
If so, the replacement cells would not necessarily be destroyed. "I am
very
optimistic on the future of transplantation therapies for Parkinson's,
but a lot
of work is needed to straighten out the kinks," Dr. Morrison said.
Dr. McKay's recipe for dopamine-making cells draws on the extensive
knowledge
that biologists have now accumulated about the genes that switch on and
off in
various groups of cells in the developing embryo.
To mature the cells, he exposes them to potent signalling factors with
names
like sonic hedgehog and fibroblast growth factor-8. He also inserts a
gene
called Nurr1 whose product is an internal switching signal that makes
cells of
the mid-brain turn into dopamine-making cells.
In terms of a cell therapy treatment for Parkinson's, Dr. McKay said
it would
take two years of experiments with his cells in monkeys and two years to
set up
a clinical trial.
Of more immediate use to patients, he said, was the fact
dopamine-making
cells could now be made in profusion and studied in the laboratory.
Scientists
could hope to understand better what agents were killing the cells in
Parkinson's patients and what drugs might protect the cells.
http://www.nytimes.com
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