The aim of this study was to examine the effects of human overweight and obesity in subcutaneous fat tissue secretion from myogenesis and metabolism in skeletal muscle cells. The hormone resistin, secreted by the subcutaneous fat tissue of obese humans, impairs formation of the human skeletal muscle, especially of the elderly, by reducing the muscle metabolism during the development of polynuclear muscle fibers (myotubes).

The hormone resistin was excreted by adipose subcutaneous fat tissue and affected the thickness and fusion of polynuclear muscle fibers (myotubes) by activating the classic inflammation pathway NFκB. Resistin also promoted lipid accumulation in the polynuclear fibers. Conversely, a removal of resistin from the fatty tissue secretion restored myogenesis function. The inhibition of the classical NFκB pathway protected myoblasts from the harmful effects of resistin.

The researchers observed that the myogenesis of old donors (>65 years) is affected, however, not the the young donors (18-30 years old).

The results may provide important evidence for maintaining muscle mass in older people with chronic inflammatory diseases or older obese or overweight people.

The scientists have published their findings in the Journal Scientific Reports:
Mary F. O'Leary, Graham R. Wallace, Edward T. Davis, David P. Murphy, Thomas Nicholson, Andrew J. Bennett, Kostas Tsintzas & Simon W. Jones (2018). Obese subcutaneous adipose tissue impairs human myogenesis, particularly in old skeletal muscle, via resistin-mediated activation of NFκB. 8:15360, DOI:10.1038/s41598-018-33840-x

Further information:
https://frame.org.uk/2019/01/31/animal-free-research-sheds-light-on-the-association-between-obesity-and-skeletal-muscle-loss/