title: The acute satellite cell response and skeletal muscle hypertrophy following resistance training.
abstract: The extent of skeletal muscle hypertrophy in response to resistance training is highly variable in humans. The main objective of this study was to explain the nature of this variability. More specifically, we focused on the myogenic stem cell population, the satellite cell (SC) as a potential mediator of hypertrophy. Twenty-three males (aged 18-35 yrs) participated in 16 wk of progressive, whole body resistance training, resulting in changes of 7.9±1.6% (range of -1.9-24.7%) and 21.0±4.0% (range of -7.0 to 51.7%) in quadriceps volume and myofibre cross-sectional area (CSA), respectively. The SC response to a single bout of resistance exercise (80% 1RM), analyzed via immunofluorescent staining resulted in an expansion of type II fibre associated SC 72 h following exercise (pre: 11.3±0.9; 72 h: 14.8±1.4 SC/type II fibre; p<0.05). Training resulted in an expansion of the SC pool associated with type I (pre: 10.7±1.1; post: 12.1±1.2 SC/type I fibre; p<0.05) and type II fibres (pre: 11.3±0.9; post: 13.0±1.2 SC/type II fibre; p<0.05). Analysis of individual SC responses revealed a correlation between the relative change in type I associated SC 24 to 72 hours following an acute bout of resistance exercise and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.566, p = 0.012) and the relative change in type II associated SC following 16 weeks of resistance training and the percentage increase in quadriceps lean tissue mass assessed by MRI (r2 = 0.493, p = 0.027). Our results suggest that the SC response to resistance exercise is related to the extent of muscular hypertrophy induced by training.
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Leeann M
authors.initials: LM
authors.lastname: Bellamy
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Sophie
authors.initials: S
authors.lastname: Joanisse
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Grubb
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Cameron J
authors.initials: CJ
authors.lastname: Mitchell
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Bryon R
authors.initials: BR
authors.lastname: McKay
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Phillips
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Steven
authors.initials: S
authors.lastname: Baker
authors.affiliation: Department of Kinesiology, McMaster University, Hamilton, Ontario, Canada; Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada.
authors.forename: Gianni
authors.initials: G
authors.lastname: Parise
mesh_terms: D000293:Adolescent; D000328:Adult; D002453:Cell Cycle; D049109:Cell Proliferation; D006801:Humans; D006984:Hypertrophy; D008297:Male; D018657:Muscle Fibers, Slow-Twitch / Q000502:physiology*; D018482:Muscle, Skeletal / Q000166:cytology / Q000502:physiology; D055435:Myostatin / Q000378:metabolism; D051763:PAX7 Transcription Factor / Q000235:genetics / Q000378:metabolism; D055070:Resistance Training; D032496:Satellite Cells, Skeletal Muscle / Q000502:physiology*; D055815:Young Adult
chemical_list: C525911:MSTN protein, human; D055435:Myostatin; D051763:PAX7 Transcription Factor; C497321:PAX7 protein, human