Faculty Opinions recommendation of Mechanisms of muscle atrophy and hypertrophy: implications in health and disease.

Muscle atrophy is usually caused by interruption of axonal flow (axonal neuropathies, motor neuron diseases, etc.). If weakness is out of proportion to atrophy, conduction block due to demyelinating neuropathy should be suspected. Chronic myopathies and immobility may also cause atrophy, but no EMG evidence of denervation or myopathy is respectively found. The pattern of atrophy is often helpful to localize the lesion. Atrophy of the interossi and preservation of the bulk of the thenar muscles suggest ulnar neuropathy, but atrophy of both would suggest a C8 or plexus pathology. Muscle enlargement may be due to tissue replacement (fatt, amyloid), which can be confirmed by EMG and MRI, or may be due to real muscle hypertrophy from excessive discharges (neuromyotonia).

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Muscle Atrophy and Hypertrophy Signaling in Patients with Chronic Obstructive Pulmonary Disease

American Journal of Respiratory and Critical Care Medicine ◽

10.1164/rccm.200605-704oc ◽

2007 ◽

Vol 176 (3) ◽

pp. 261-269 ◽

Cited By ~ 145

Author(s):

Mariève Doucet ◽

Aaron P. Russell ◽

Bertrand Léger ◽

Richard Debigaré ◽

Denis R. Joanisse ◽

...

Keyword(s):

Chronic Obstructive Pulmonary Disease ◽

Pulmonary Disease ◽

Muscle Atrophy ◽

Chronic Obstructive ◽

Obstructive Pulmonary Disease ◽

Atrophy And Hypertrophy

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Electrical Impedance as a Novel Biomarker of Myotube Atrophy and Hypertrophy

CrossRef Listing of Deleted DOIs ◽

10.1177/1087057111401392 ◽

2011 ◽

Vol 16 (6) ◽

pp. 565-574 ◽

Cited By ~ 22

Author(s):

Sergey Rakhilin ◽

Gordon Turner ◽

Mark Katz ◽

Robert Warden ◽

Jeff Irelan ◽

...

Keyword(s):

Muscle Atrophy ◽

Electrical Impedance ◽

Cellular Adhesion ◽

Skeletal Muscle Atrophy ◽

Novel Treatments ◽

Novel Method ◽

Quantitative Changes ◽

Atrophy And Hypertrophy ◽

Myotube Hypertrophy ◽

Therapeutic Compounds

Measuring myotube thickness is a physiological and unbiased approach for screening therapeutic compounds that prevent skeletal muscle atrophy or induce hypertrophy. However, an accurate cell thickness estimate is often quite challenging because of the extreme heterogeneity of the myotube cellular population and therefore the lack of a regular distribution of perturbed myotubes. Here the authors present a novel method to evaluate changes in myotube thickness via measuring cellular electrical impedance. They demonstrate that both qualitative and quantitative changes in electrical impedance as a function of cellular adhesion in real time correlate well with variation in myotube thickness caused by atrophy or hypertrophy agents. Conversely, pharmacologically blocking myotube hypertrophy prevents changes in electrical impedance. Thus, impedance can be used as a reliable and sensitive biomarker for myotube atrophy or hypertrophy. Application of this technique to drug screening might be beneficial in finding novel treatments preventing muscle atrophy and other diseases associated with any morphological change in cell shape.

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