Myostatin Blockers: The Potential Benefits and Risks of These Forthcoming 'Super-Muscle' Drugs
by www.SixWise.com
In 2000, a boy was born in Charite Hospital in Berlin, Germany.
Unlike the other babies, his muscles were not soft and undefined.
They were bulging from his arms and legs. As the child grew,
he developed muscles twice the size of his peers, while maintaining
half the body fat, and before the age of 4 he was able to
hold seven-pound weights with his arms extended.
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A boy born in Germany in 2000 is the first known human
to have a mutation in the myostatin protein, which results
in enhanced muscle growth (he is 7 months old in this
picture).
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This little Hercules, who is now a healthy 7-year-old, is
the first human with a proven mutation in myostatin, a protein
that limits muscle growth.
By blocking this protein, for instance, researchers have
grown muscular mice they call "mighty mice," and
cattle breeders have developed the Belgian Blue breed -- the
so-called "double muscle" cattle that are especially
meaty and very lean.
The discovery of the myostatin mutation in a human, however,
has sparked significant interest in myostatin-blocking drugs,
which are surrounded by a growing sea of debate.
Myostatin Blockers for Muscular Dystrophy and Diabetes?
Myostatin-blocking drugs could theoretically help people
with Duchenne muscular dystrophy and similar diseases that
destroy muscle, such as cancer, AIDS, and even normal aging.
Astronauts, who lose muscle mass after being in zero-gravity
for prolonged periods, could also potentially benefit from
such drugs.
Pharmaceutical company Wyeth has already gained the rights
to develop a human myostatin blocker, and has begun testing
a version with antibodies that block the protein in adults.
Results are expected as early as March of this year.
"Just decreasing this protein by 20, 30, 50 percent
can have a profound effect on muscle bulk," said Dr.
Lou Kunkel, director of the genomics program at Boston Children's
Hospital and professor of pediatrics and genetics at Harvard
Medical School (and also a doctor participating in the Wyeth's
research).
Further, according to Dr. Se-Jin Lee, a Johns Hopkins professor
who helped create the "mighty mice" (and who, along
with Johns Hopkins, would receive royalties for Wyeth's drug),
a myostatin blocker may also be able to suppress fat accumulation
and help stop the development of diabetes.
Potential Problems Down the Road?
While proponents say the drugs hold promise, others express
concern at potential side effects of blocking the myostatin
protein, which are completely unknown at this time.
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While myostatin blockers hold promise for those with
serious diseases like muscular dystrophy, they could
also be abused by bodybuilders and athletes looking
to gain a competitive edge.
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One possible concern, according to Dr. Markus Schuelke, the
pediatric neurologist at Charite University Medical Center
in Berlin who discovered the myostatin mutation in the baby,
is that blocking myostatin could interfere with satellite
cells that help replace injured or dead muscle cells. It's
thought that myostatin helps keep the satellite cells at rest
until they're needed, and it's possible that without myostatin
the satellite cells could become depleted.
Meanwhile, some say myostatin blockers may be too targeted
to boost muscle growth, as there are a variety of proteins
similar to myostatin that also limit muscle growth.
Another drug company, Acceleron Pharma, is planning to test
a drug on humans that reportedly blocks not just myostatin
but also many of the other similar proteins.
Myostatin-Blockers Could Become the New "Steroids"
Other companies looking to gain a piece of the myostatin
fortune include food producers, who are looking to alter animals
such as chickens so they contain more meat, and supplement
companies, which are already promoting myostatin-blocking
alternatives made from sea algae to body builders and other
athletes.
"Myostatin blockade," said Dr. Elizabeth McNally
of the University of Chicago, "will probably work its
way into professional and amateur athletics, as well as into
the ever-growing business of physical enhancement."
Experts say the knock-off supplements currently on the market
don't work and could carry unknown health risks, as could
the real myostatin-blockers that may one day be available
not only to those with serious illnesses but also to those
looking to simply "beef up" their physique.
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Sources
Forbes.com
February 26, 2007
The
New York Times
MSNBC.com