|Michael J. Fox|
The reining in of stem cell expectations continues. This week in Science,
Constance Holden writes about the rise and fall--and potential second
rise--of the hopes for cellular therapy for Parkinson's disease.
[A]s the lab research proceeds
apace, there's growing doubt in some quarters about whether cell
transplants will ever show a clear benefit for Parkinson's disease
beyond what can be achieved by existing therapies....
A half-dozen years ago, in the heat of political and scientific
excitement over hES [human embryonic stem] cells, Parkinson's disease
was regarded as one of the prime candidates for stem cell therapy. But
even as iPS [induced pluripotent stem] cells have opened new vistas,
the prospect of cell therapy trials has been steadily receding as
scientists have gained new appreciation of both the difficulties of
cell culture and the complexity of the disease itself....
Stem cell treatment "looked most hopeful when people were treating
[Parkinson's] just as a dopamine disease," says [neurologist C. Warren]
Olanow. Degeneration of dopamine-producing cells is not the first or
the only symptom of Parkinson's, however. It's become increasingly
clear that, as neurologist J. William Langston of the Parkinson's
Institute and Clinical Center in Sunnyvale, California, has put it,
"Parkinsonism (that is, dopamine-related movement problems) is just the
tip of the iceberg."...
Olanow notes the limitations that pertain to dopamine-focused cell
therapy also apply to current Parkinson's disease gene-therapy efforts,
which center on introducing one or more genes involved in dopamine
The Michael J. Fox Foundation for Parkinson's Research has also
become much more cautious about the promise of cell therapy. The
foundation is now placing its bets on new drug development and supports
very little stem cell research. "I was totally na´ve when I came to the
foundation" in 2002, says CEO Katie Hood. "All my exposure was pop
media; I thought it was all about stem cells." Now, she says, "I have
not totally lost hope on cell replacement," but "I just don't think
it's a near-term hope."
The namesake of the Michael J. Fox Foundation has himself been quite a booster of stem cell research, particularly in the 2004, 2006 (1, 2), and 2007 elections.
Previously on Biopolitical Times:
Posted in Jesse Reynolds's Blog Posts, Stem Cell Research
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