posted May 11, 2000 03:19 PM            

Hope has arrived for the world's 98-pound weaklings,
says a Canadian researcher who has found a way to
flick the cellular switch that produces muscles.
"We will now have the ability to make more muscle
when we want it and where we need it," said Dr. Judy
Anderson, a muscle cell biologist at the University of
Manitoba.
Dr. Anderson says the research can also be applied
to disease treatment, ageing, agriculture, sports medicine
and even space travel.
Until now, the only way to boost muscle growth was
through disease or by injury.
Weightlifting, for example, creates many micro-injuries
that cause a muscle to grow as the tissue is repaired.
"Muscle cells are long, cigar-shaped tubes that go
between tendons," Dr. Anderson explains.
When something goes wrong in a muscle cell, it sends
nitric oxide to so-called satellite cells just above the muscle
fiber, which sparks a muscle-growth process.
"We haven't known how to turn on these satellite cells
before," Dr. Anderson says.
"Now that we do, we have the potential to optimize muscle
repair for those who use wheelchairs or others who are not
able to exercise and maintain regular movement."
Nitric oxide can be released in many ways, such as
stretching muscles, or through muscle and nerve damage.
In some diseases, such as muscular dystrophy, this
nitric oxide signal is disrupted, so that muscle tissue
wastes away over time.
In a study published in the journal Molecular Biology
of the Cell, Dr. Anderson shows how certain compounds
can stimulate the amount of nitric oxide that muscles release.
"Let me tell you, we've got mice that are on these compounds
that are bigger, stroger and their satellite cells are activated,"
she says.
"After only a week, there's a major difference in what their
muscles are doing. I don't know if we've got Arnold
[Schwarzeneggers], but we've got big changes for sure."
Dr. Anderson sees the first applications of the procedure in
rehabilitative medicine.
"You could say, 'Well, I'm going for surgery. I need the muscle
as busy as it can be as soon as that can happen. So I'm going
to activate those cells now, just before surgery, and I need
those repairs faster.' Or let's say you've had a stroke and you
want your rehabilitation to go really well, so you could actually
maintain muscle mass through this mechanism while you were
allowing your nervous system to repair from this stroke."
The technique also has applications for ordinary ageing.
After age 30, muscle mass begins to dwindle in most adults.
This causes a loss of "pull" on bones, which leads to osteoporosis,
the loss of bone density. Similarly, the weightless environment of
space travel is understood to decrease muscle mass, even
when astronauts do plenty of exercise.
"One of the things that we're going to be testing is how that will
augment meat production in agriculture," says Dr. Anderson.
"Nitric oxide is something that all species have, so I expect that
fish, chickens and all kinds of things could be affected."
While Olympic athletes and bodybuilders will no doubt be
interested, Dr. Anderson says this technology can also be
used to test for illegal muscle-building drug use. "There's a
possibility to turn this around another way and use it as a
screening tool," she says.
Stimulating nitric oxide is a superior technique to steroids
and other compounds, she says, because it is the body's
natural muscle-growth system and it is specific.