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FASEB J. 2013 Nov;27(11):4596-605. doi: 10.1096/fj.13-229799. Epub 2013 Aug 8.

Evidence for the contribution of muscle stem cells to nonhypertrophic skeletal muscle remodeling in humans.

Author information

1
1Departments of Kinesiology and Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada L8S 4L8. pariseg@mcmaster.ca.

Abstract

The purpose of this study was to explore the possible role of muscle stem cells, also referred to as satellite cells (SCs), in adaptation and remodeling following a nonhypertrophic stimulus in humans. Muscle biopsies were obtained from the vastus lateralis of previously untrained women (n=15; age: 27±8 yr, BMI: 29±6 kg/m(2)) before and after 6 wk of aerobic interval training. The fiber type-specific SC response to training was analyzed using immunofluorescent microscopy of muscle cross sections. Following training, the number of SCs associated with fibers expressing myosin heavy-chain type I and II isoforms (hybrid fibers) increased (pre: 0.062±0.035 SC/hybrid fiber; post: 0.38±0.063 SC/hybrid fiber; P<0.01). In addition, there was a greater number of MyoD(+)/Pax7(-) SCs, indicative of differentiating SCs, associated with hybrid fibers (0.18±0.096 MyoD(+)/Pax7(-) SC/hybrid fiber) compared to type I (0.015±0.00615 MyoD(+)/Pax7(-) SC/type I fiber) or II (0.012±0.00454 MyoD(+)/Pax7(-) SC/type II fiber) fibers (P<0.05). There was also a training-induced increase in the number of hybrid fibers containing centrally located nuclei (15.1%) compared to either type I (3.4%) or II fibers (3.6%) (P<0.01). These data are consistent with the hypothesis that SCs contribute to the remodeling of muscle fibers even in the absence of hypertrophy.

KEYWORDS:

Pax7; aerobic interval training; satellite cells

PMID:
23928822
PMCID:
PMC3804745
DOI:
10.1096/fj.13-229799
[Indexed for MEDLINE]
Free PMC Article

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