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Preserved capacity for satellite cell proliferation, regeneration, and hypertrophy in the skeletal muscle of healthy elderly men
Author(s) -
Karlsen Anders,
Soendenbroe Casper,
MalmgaardClausen Nikolaj M.,
Wagener Frederik,
Moeller Casper Emil,
Senhaji Zouhir,
Damberg Kristine,
Andersen Jesper Løvind,
Schjerling Peter,
Kjaer Michael,
Mackey Abigail L.
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.202000196r
Subject(s) - muscle hypertrophy , regeneration (biology) , medicine , skeletal muscle , immunohistochemistry , myogenesis , endocrinology , myocyte , biology , microbiology and biotechnology
Blunted muscle hypertrophy and impaired regeneration with aging have been partly attributed to satellite cell (SC) dysfunction. However, true muscle regeneration has not yet been studied in elderly individuals. To investigate this, muscle injury was induced by 200 electrically stimulated (ES) eccentric contractions of the vastus lateralis (VL) of one leg in seven young (20‐31 years) and 19 elderly men (60‐73 years). This was followed by 13 weeks of resistance training (RT) for both legs to investigate the capacity for hypertrophy. Muscle biopsies were collected Pre‐ and Post‐RT, and 9 days after ES, for immunohistochemistry and RT‐PCR. Hypertrophy was assessed by MRI, DEXA, and immunohistochemistry. Overall, surprisingly comparable responses were observed between the young and elderly. Nine days after ES, Pax7+ SC number had doubled ( P < .05), alongside necrosis and substantial changes in expression of genes related to matrix, myogenesis, and innervation ( P < .05). Post‐RT, VL cross‐sectional area had increased in both legs (~15%, P < .05) and SCs/type II fiber had increased ~2‐4 times more with ES+RT vs RT alone ( P < .001). Together these novel findings demonstrate “youthful” regeneration and hypertrophy responses in human elderly muscle. Furthermore, boosting SC availability in healthy elderly men does not enhance the subsequent muscle hypertrophy response to RT.