In response to Point: Counterpoint : "Satellite cell addition is/is not obligatory for skeletal muscle hypertrophy"

• In this letter, the point: counterpoint issue (1, 5) is addressed solely by referring to studies in humans. The analysis of histological sections from skeletal muscle of power lifters with many years of practice leaves no doubt about the role of satellite cells as myonuclei donors in the hypertrophied muscle fibre. The larger the cross-sectional area of fibres, the higher the number of myonuclei per cross-section (2, 4). Importantly, the strong relationship between the cross-sectional area of fibres and the number of myonuclei (r = 0,86; p < 0.0001) is obtained with a range of areas between 2500 µm2 and 14000 µm2 (4). Existing myonuclei are able to sustain an initial hypertrophy of the muscle fibre as long as the transcriptional activity of existing myonuclei does not reach its maximum (2, 3, 5). Satellite cells become myonuclei donors when fibre size reaches the ceiling size (2, 3, 5). Additionally, we should not forget that satellite cells are also donors of myonuclei to newly generated myotubes (2, 4). The intensity of exercise and the initial fibre area of the subjects included in a training program are important factors governing whether daughter cells generated by satellite cell activation and proliferation provide new myonuclei to existing myofibres or to newly generated myotubes. Finally, in parallel with these events, some of the daughter cells can escape differentiation and facilitate renewal of the satellite cell pool. Efforts should be made to better understand key elements guiding the fate of satellite cells.

Ämnesord

SAMHÄLLSVETENSKAP  -- Annan samhällsvetenskap -- Tvärvetenskapliga studier inom samhällsvetenskap (hsv//swe)

SOCIAL SCIENCES  -- Other Social Sciences -- Social Sciences Interdisciplinary (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Hälsovetenskap -- Idrottsvetenskap (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Health Sciences -- Sport and Fitness Sciences (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

Humans

Muscle Development/*physiology

Muscle Fibers/*physiology

Muscle; Skeletal/*cytology/physiology

Satellite Cells; Skeletal Muscle/*physiology

INTERDISCIPLINARY RESEARCH AREAS

TVÄRVETENSKAPLIGA FORSKNINGSOMRÅDEN

Sports

Idrott

MEDICINE

MEDICIN

Physiology

Fysiologi

Sports Science

Idrottsvetenskap

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