In his closing comments to a scientific congress in 1989, Dr. Irwin Rosenberg suggested that one way to bring greater attention to the issue of the decline in muscle mass with aging was to give it a Greek name (26). Although two terms were suggested (“sarcomalacia” being the other one), “sarcopenia” was the term adopted by the field. A PubMed search for sarcopenia as of this writing yielded mor...

Skeletal muscle atrophy is a debilitating process associated with a wide variety of conditions including inactivity, disease and aging. Here, we demonstrate that the actin/Mrtfs/Srf pathway is specifically downregulated in muscle atrophy induced by disuse in mice. We show in vivo that the abolition of mechanical signals leads to rapid accumulation of G-actin in myonuclei and export of the Srf c...

Skeletal muscles of old rats and elderly humans lose muscle mass and maximum force. Denervation is a major cause of age-related muscle atrophy and weakness, because denervated fibers do not contract, and undergo atrophy. At any age, surgical denervation causes even more dramatic muscle atrophy and loss in force than aging does. Electrical stimulation that generates tetanic contractions of dener...

Skeletal muscle is a plastic organ that is maintained by multiple pathways regulating cell and protein turnover. During muscle atrophy, proteolytic systems are activated, and contractile proteins and organelles are removed, resulting in the shrinkage of muscle fibers. Excessive loss of muscle mass is associated with poor prognosis in several diseases, including myopathies and muscular dystrophi...

Chemotherapy can cause cachexia, which is manifested by weight loss, inflammation and muscle atrophy. However, the mechanisms of tumor and chemotherapy on skeletal muscle proteolysis, remained unclear. In this report, we demonstrated that tumor-induced myostatin in turn induced TNF-α, thus activating calcium-dependent and proteasomal protein degradation. Chemotherapy activated myostatin-mediate...

PURPOSE OF REVIEW To highlight recent breakthroughs and controversies in the use of myoblast models to uncover cellular and molecular mechanisms regulating skeletal muscle hypertrophy and atrophy. RECENT FINDINGS Myoblast cultures provide key mechanistic models of the signalling and molecular pathways potentially employed by skeletal muscle in-vivo to regulate hypertrophy and atrophy. Recentl...

We employed RU 38486, a potent and selective antiglucocorticoid, to study a possible role for endogenous glucocorticoids in atrophy of the levator ani muscle secondary to castration of male rats. RU 38486 was shown to block [3H]triamcinolone acetonide binding to cytosol from levator ani muscle. Daily oral administration of RU 38486 to castrated rats partially prevented atrophy of the levator an...

Skeletal muscle atrophy in response to a number of muscle wasting conditions, including disuse, involves the induction of increased protein breakdown, decreased protein synthesis, and likely a variable component of apoptosis. The increased activation of specific proteases in the atrophy process presents a number of potential therapeutic targets to reduce muscle atrophy via protease inhibition. ...

AIM In the assessment of the lumbar spine by magnetic resonance imaging (MRI), changes in the paraspinal muscles are frequently overlooked. In this study, our objective was to investigate the relationships between lumbar multifidus (MF) muscle atrophy and low back pain (LBP), leg pain and intevertebral disc degeneration. METHODS A retrospective study of 78 patients (aged 17-72) with LBP prese...

Skeletal muscle atrophy is a consequence of several physiological and pathophysiological conditions including muscle disuse, aging and diseases such as cancer and heart failure. In each of these conditions, the predominant mechanism contributing to the loss of skeletal muscle mass is increased protein turnover. Two important mechanisms which regulate protein stability and degradation are lysine...