Muscle Atrophy

Muscle atrophy is the loss of muscle tissue and can result from disuse, disease and as a normal consequence of aging. Disuse is the most common cause of atrophy and even minor muscle atrophy can lead to limb weakness or impaired movement ability.

Disuse Atrophy

• Disuse atrophy is caused by lack of exercise and often afflicts people who work at sedentary jobs or experience long-term immobilization through being bedridden or wearing casts. In extreme cases, the connective tissue no longer replaces skeletal muscle fibers and disuse atrophy becomes irreversible.

Aging

• As people age, the biochemical signals muscle tissue sends to adult stem cells changes, resulting in decreased stem cell activity in repairing and regenerating muscle tissue. A University of California study suggests that therapy involving mitogen-activated protein kinase, a regulator of stem cell activity, could reduce age-related atrophy.

Other Causes

• Neurogenic atrophy occurs when nerves attached to muscles are afflicted with injury or diseases including amyotrophic lateral sclerois, also known as Lou Gherig's disease, muscular dystrophy and polio. Malnourishment can lead to muscle atrophy as the body breaks down skeletal muscle to provide protein, a phenomenon that also occurs in cancer and AIDS patients.