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A Fountain
of Youth in Your Muscles
December 1, 2010--Working out can help you
shed pounds — but that's just the beginning.
New research fromTel Aviv University has
found that "endurance exercises," like a
Central Park jog or a spinning class, can
make us look younger. The key, exercise,
unlocks the stem cells of our muscles.
Prof. Dafna Benayahu and
her team at Tel
Aviv University's Sackler
School of Medicine say
their findings explain for the first time
why older people who have exercised
throughout their lives age more gracefully.
They have discovered how endurance exercise
increases the number of muscle stem cells
and enhances their ability to rejuvenate old
muscles. The researchers hope their finding
can lead to a new drug to help the elderly
and immobilized heal their muscles faster.
The results of the study were recently
published in the journal PLoS
ONE.
The real rat race
The muscles and skeleton in our bodies work
together, explains Prof. Benayahu. "When we
age, we experience sarcopenia, a decline in
mass and function of muscles, and osteopenia
referrers to bone loss," she says.
As a result, our musculoskeletal system is
more susceptible to daily wear and tear,
which also explains the increased risk of
falling in the elderly.
Investigating a rat population, Dr.
Gabi Shefer from
the research team says that the finding
shows that exercise increased the number of
satellite cells (muscle stem cells) — a
number which normally declines with aging.
The researchers believe that a decline in
the number of these cells and their
functionality may prevent proper maintenance
of muscle mass and its ability to repair
itself, leading to muscle deterioration.
Comparing the performance of rats of
different ages and sexes, they found that
the number of satellite cells increased
after rats ran on a treadmill for 20 minutes
a day for a 13-week period.
The younger rats showed a 20% to 35%
increase in the average number of stem cells
per muscle fiber retained — and older rats
benefited even more significantly,
exhibiting a 33% to 47% increase in stem
cells.
A good reason to get up and dance
Endurance exercise also improved the levels
of "spontaneous locomotion" — the feeling
that tells our bodies to just get up and
dance — of old rats. Aging is typically
associated with a reduced level of
spontaneous locomotion.
The combination of aging and a sedentary
lifestyle significantly contributes to the
development of diseases such as
osteoporosis, obesity, diabetes and
cardiovascular diseases, as well as a
decline in cognitive abilities.
If researchers can discover a method to
"boost" satellite cells in our muscles, that
could simulate the performance of young and
healthy muscles — and hold our aging bones
in place.
"We hope to understand the mechanisms for
the activation codes of muscle stem cells at
the molecular level," says Prof. Benayahu.
"With this advance, we can let ourselves
dream about creating a new drug for humans —
one that could increase muscle mass and
ameliorate the negative effects of aging."
Grants for this study were provided by the
EU-FP7 Excell project; the Israeli Ministry
of Health; and the U.S. – Israel Binational
Science Foundation jointly with Prof.
Yablonka-Reuveni from the University of
Washington.
