Muscle loss finding may one day save physiques

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Muscle loss finding may one day save physiques

http://www.eurekalert.org/pub_releases/2010-02/uoth-mlf021210.php

Hey guys, remember the muscle shirts we wore in our teens and 20s? After the age

of 40 that meager part of our wardrobes usually is obsolete. Yes, at the big 4-0

we begin to lose muscle, and by age 80 up to a third of it may be gone. It's an

inevitable process of aging called sarcopenia.

Why does sarcopenia happen and can it be stopped? A study conducted in mice with

accelerated muscle loss at The University of Texas Health Science Center at San

provides this insight: Less protection from antioxidants and more damage

from oxidative stress results in impairment to cells' energy centers, which

slowly leads to death of muscle cells.

A team directed by Holly Van Remmen, Ph.D., associate professor with the

university's Barshop Institute for Longevity and Aging Studies and the

Department of Cellular and Structural Biology, found that without a certain

antioxidant enzyme to balance the formation of harmful reactive oxygen species

(ROS), cellular energy centers called mitochondria fail to work properly. The

mitochondria even add to the spate of ROS molecules and release factors leading

to cell death.

" The impaired function of mitochondria also has a detrimental effect on the way

motor neurons 'talk' to the muscle to achieve muscle contraction, " Dr. Van

Remmen said. " This interaction occurs at a specialized synapse where the nerve

and muscle come in close contact. " This key structure is called the

neuromuscular junction, she said.

Smaller and weaker muscles

Youngmok C. Jang, Ph.D., a leading author in the study, investigated mice that

were genetically engineered to lack an antioxidant enzyme called copper-zinc

superoxide dismutase. He compared mitochondria from these mice and normal mice

and found reduced function of the energy centers in the enzyme-deficient mice.

This contributed to more cell death and muscle atrophy in the rodents. " As a

result, their muscles were a lot smaller and weaker, " Dr. Van Remmen said.

Insights gleaned about muscle loss can help scientists better understand other

neuromuscular diseases such as amyotrophic lateral sclerosis (Lou Gehrig's

disease). " Age-related muscle atrophy is a complex process and involves multiple

systems, " Dr. Van Remmen said. " There are, however, common mechanisms occurring

in sarcopenia and other neuromuscular diseases. By understanding the mechanisms

underlying age-related muscle atrophy and alterations at the neuromuscular

junction, we should be able to gain insight that will help us to discover new

therapeutic interventions. "

If a muscle-preserving therapy is one day developed, future generations of young

men will be able to keep their muscle shirts a bit longer.

Note: A grant from the National Institute on Aging supported this project, along

with a Mid-Career Award in Aging Research to Dr. Van Remmen from

the American Federation for Aging Research. Co-authors from the UT Health

Science Center are Youngmok Jang, Ph.D.; Lustgarten, Ph.D.; Yuhong Liu;

Florian Muller, Ph.D.; Arunabh Journal on Bhattacharya, Ph.D.; Hanyu Liang,

Ph.D.; Adam Salmon, Ph.D.; and Arlan , Ph.D. Other co-authors are

, Ph.D., and Larkin, Ph.D., of The University of Michigan and

Hayworth, Ph.D., of The University of Texas at Austin. Drs. Van

Remmen and have joint appointments with the South Texas Veterans

Health Care System. This paper was published online by The FASEB Dec. 29, 2009.