Stem cell studies hopeful but time needed for cures
Overpromising research could jeopardize its future
By DAVID A. SHAYWITZ
LAST week the National Academies released new guidelines for research
involving human embryonic stem cells, the latest milestone in what has been
an unusually eventful time for investigators in this field. Last November
the voters of California approved $3 billion in funding for stem cell
research, and earlier this month Massachusetts lawmakers approved powerful
new legislation that defines and defends this exciting new area of science.
Yet, unless proponents of stem cell research learn to preach patience as
well as promise, their celebration will be short-lived.
Human embryonic stem cells were first identified less than a decade ago.
They captured the attention of scientists because of two essential
properties: They can duplicate themselves in a culture dish, and they can
go on to form any cell type in the body. The therapeutic potential seems
both apparent and unlimited: Convert these cells into neurons and treat
Parkinson's disease, the reasoning goes; turn them into insulin cells and
cure diabetes.
That's the plan, anyway. In fact, the deliberate conversion of human
embryonic stem cells into any other type of cell remains a formidable
scientific challenge. Even growing these stubborn cells is notoriously
difficult. And even if we could make replacement cells in a culture dish,
we would still face the daunting task of introducing them into the body.
The real question, however, isn't whether these problems will be solved,
but when. And here, the unfortunate truth is that science ? good science ?
can be maddeningly slow. While stem cell advocates have helped voters
connect embryonic stem cell research with compelling images of patients who
might one day benefit from treatment, such therapies are unlikely to emerge
soon enough to benefit most current proponents ? although patients with
Type 1 diabetes may represent an important exception.
Soon the advocacy groups that have been so instrumental in supporting stem
cell science will face mounting pressure to demonstrate that they have bet
on the right technology. From the researchers, tremendous progress will be
expected, and the science is unlikely to keep pace with the eager expectations.
This scenario has a familiar ring. For years it was not stem cells but gene
therapy ? the idea of fixing a disease by mending broken DNA ? that seemed
to be the ultimate expression of molecular medicine. Cures, we were told,
lay just around the corner. Unfortunately, success turned out to be much
harder to achieve in people than to diagram on a chalkboard. The tragic
death of clinical study volunteer Jesse Gelsinger, and the concurrent
realization that the promised cures were years away, finally burst the
bubble. Today a disappointingly small number of hardy investigators remain
in what was once medicine's most highly anticipated new area of research.
Is this going to be the fate of embryonic stem cell science in five or 10
years? I hope not, and yet it's also not very difficult to imagine this
happening. Already newspapers are filled with extravagant claims of
progress and cures. These reports belie the very slow rate of true
scientific advancement. Add to this the explicit expectation of rapid
clinical progress ? a key component of California's recently approved stem
cell initiative, for example ? and you have a recipe for trouble. If
embryonic stem cells are rushed into clinical trials before the solid
science has been done, the resulting fiasco could easily doom the entire
future of the field.
How can we avoid this fate? For starters, scientists must do a better job
of articulating the limitations of our existing knowledge, taking care to
emphasize not only the ultimate therapeutic potential of these cells, but
also how far we are from achieving such therapies. Advocacy groups must
also level with their stakeholders and explain why treatments based on stem
cells will take such a long time to materialize ? and why the wait is worth
it. At the same time, these organizations must continue to push scientists
to work harder and achieve results faster, encouraging investigators to
keep in mind the patients in whose name the research is being conducted
(and funded).
Editors of scientific journals, as well as mainstream reporters, must shape
up as well. Research articles of questionable quality shouldn't be accepted
for publication, even if they are certain to garner significant media
coverage. Similarly, journalists must resist the temptation to lavish
attention on every published scientific article with the words "stem cell"
in the title.
Finally, we would all do well to keep in mind that in contrast to the tidy,
syncopated tableau of television's "CSI," science in the real world is
frequently tedious and almost always messy. But there are also moments of
great clarity and wondrous insight ? moments I anticipate we will
experience with increasing frequency in stem cell research. In the end, I
suspect embryonic stem cells will evolve into a therapeutic tool even more
useful than anything we can now envision. But the development of this
entirely new area of science will take dedication, funding and, above all,
time. "Genius is eternal patience," Michaelangelo observed. Let us hope
that for those looking to stem cells for treatment, the wait will not be
quite so long.
Shaywitz is an endocrinologist and stem cell researcher at Harvard
University.
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