The impact of sarcopenia and exercise training on skeletal muscle satellite cells
ABSTRACT It has been well-established that the age-related loss of muscle mass and strength, or sarcopenia, impairs skeletal muscle function and reduces functional performance at a more advanced age. Skeletal muscle satellite cells (SC), as precursors of new myonuclei, have been suggested to be involved in the development of sarcopenia. In accordance with the type II muscle fiber atrophy observed in the elderly, recent studies report a concomitant fiber type specific reduction in SC content. Resistance type exercise interventions have proven effective to augment skeletal muscle mass and improve muscle function in the elderly. In accordance, recent work shows that resistance type exercise training can augment type II muscle fiber size and reverse the age-related decline in SC content. The latter is supported by an increase in SC activation and proliferation factors that generally appear following exercise training. Present findings strongly suggest that the skeletal muscle SC control myogenesis and have an important, but yet unresolved, function in the loss of muscle mass with aging. This review discusses the contribution of skeletal muscle SC in the age-related loss of muscle mass and the efficacy of exercise training as a means to attenuate and/or reverse this process.
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- "Because of the post-mitotic status of the myonuclei, an increased number of myonuclei depends on nuclear donation from satellite cells, which are muscle progenitor cells found in a quiescent state between the basal lamina and the sarcolemma (Kadi et al., 2004). It has been shown that increased muscle fiber CSA induced by testosterone supplementation (Sinha-Hikim et al., 2006) and by strength training (Mackey et al., 2007; Snijders et al., 2009) is paralleled with an increased number of satellite cells per muscle fiber. Short-term ADT in healthy young men has been shown to attenuate muscle mass gains (Kvorning et al., 2006) and the increase in myonuclear numbers (Kvorning et al., 2014) following strength training. "
ABSTRACT: Androgen deprivation therapy (ADT) improves life expectancy in prostate cancer (PCa) patients, but is associated with adverse effects on muscle mass. Here, we investigated the effects of strength training during ADT on muscle fiber cross-sectional area (CSA) and regulators of muscle mass. PCa patients on ADT were randomized to 16 weeks of strength training (STG) (n = 12) or a control group (CG; n = 11). Muscle biopsies were obtained from m. vastus lateralis and analyzed by immunohistochemistry and western blot. Muscle fiber CSA increased with strength training (898 μm(2) , P = 0.04), with the only significant increase observed in type II fibers (1076 μm(2) , P = 0.03). There was a trend toward a difference in mean change between groups myonuclei number (0.33 nuclei/fiber, P = 0.06), with the only significant increase observed in type I fibers, which decreased the myonuclear domain size of type I fibers (P = 0.05). Satellite cell numbers and the content of androgen receptor and myostatin remained unchanged. Sixteen weeks of strength training during ADT increased type II fiber CSA and reduced myonuclear domain in type I fibers in PCa patients. The increased number of satellite cells normally seen following strength training was not observed. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.Scandinavian Journal of Medicine and Science in Sports 08/2015; DOI:10.1111/sms.12543 · 3.17 Impact Factor
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- "Exercise Research Laboratory, Physical Education School, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil S. S. Pinto (*) : C. L. Alberton Neuromuscular Evaluation Laboratory, Physical Education School, Federal University of Pelotas, Rua Luiz de Camões, 625–Tablada, 96055-630, Pelotas, RS, Brazil e-mail: email@example.com R. Ferrari Exercise Pathophysiology Research Laboratory, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil B. M. Baroni Department of Physical Therapy, Federal University of Health Sciences of Porto Alegre, Porto Alegre, Brazil Author's personal copy Izquierdo et al. 2001; Snijders et al. 2009 "
ABSTRACT: This study investigated the effects of different exercise sequences on the neuromuscular adaptations induced by water-based concurrent training in postmenopausal women. Twenty-one healthy postmenopausal women (57.14 ± 2.43 years) were randomly placed into two water-based concurrent training groups: resistance training prior to (RA, n = 10) or after (AR, n = 11) aerobic training. Subjects performed resistance and aerobic training twice a week over 12 weeks, performing both exercise types in the same training session. Upper (elbow flexors) and lower-body (knee extensors) one-repetition maximal test (1RM) and peak torque (PT) (knee extensors) were evaluated. The muscle thickness (MT) of upper (biceps brachii) and lower-body (vastus lateralis) was determined by ultrasonography. Moreover, the maximal and submaximal (neuromuscular economy) electromyographic activity (EMG) of lower-body (vastus lateralis and rectus femoris) was measured. Both RA and AR groups increased the upper- and lower-body 1RM and PT, while the lower-body 1RM increases observed in the RA was greater than AR (34.62 ± 13.51 vs. 14.16 ± 13.68 %). RA and AR showed similar MT increases in upper- and lower-body muscles evaluated. In addition, significant improvements in the maximal and submaximal EMG of lower-body muscles in both RA and AR were found, with no differences between groups. Both exercise sequences in water-based concurrent training presented relevant improvements to promote health and physical fitness in postmenopausal women. However, the exercise sequence resistance–aerobic optimizes the strength gains in lower limbs.Journal of the American Aging Association 02/2015; 37(1). DOI:10.1007/s11357-015-9751-7 · 3.45 Impact Factor
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- "Although exercise or loading can partially rescue the reduction in satellite cell function (Dreyer et al., 2006; Snijders et al., 2009; Verdijk et al., 2009; Shefer et al., 2010), muscle fibers typically do not hypertrophy to the same extent in old animals as compared to young animals, even if the young and old animals receive the same stimulus and this is at least partially attributable to aging-suppressed satellite cell function (Carson et al., 1995; Carson and Alway, 1996; Lowe et al., 1998; Cutlip et al., 2006). Thus, while full reversal of sarcopenia does not appear to be possible, exercise, and overload nevertheless, have been used as a rehabilitative tool to compensate for sarcopenia, and can at least partially reverse the age-imposed decrements in performance. "
ABSTRACT: The mechanisms contributing to sarcopenia include reduced satellite cell (myogenic stem cell) function that is impacted by the environment (niche) of these cells. Satellite cell function is affected by oxidative stress, which is elevated in aged muscles, and this along with changes in largely unknown systemic factors, likely contribute to the manner in which satellite cells respond to stressors such as exercise, disuse, or rehabilitation in sarcopenic muscles. Nutritional intervention provides one therapeutic strategy to improve the satellite cell niche and systemic factors, with the goal of improving satellite cell function in aging muscles. Although many elderly persons consume various nutraceuticals with the hope of improving health, most of these compounds have not been thoroughly tested, and the impacts that they might have on sarcopenia and satellite cell function are not clear. This review discusses data pertaining to the satellite cell responses and function in aging skeletal muscle, and the impact that three compounds: resveratrol, green tea catechins, and β-Hydroxy-β-methylbutyrate have on regulating satellite cell function and therefore contributing to reducing sarcopenia or improving muscle mass after disuse in aging. The data suggest that these nutraceutical compounds improve satellite cell function during rehabilitative loading in animal models of aging after disuse (i.e., muscle regeneration). While these compounds have not been rigorously tested in humans, the data from animal models of aging provide a strong basis for conducting additional focused work to determine if these or other nutraceuticals can offset the muscle losses, or improve regeneration in sarcopenic muscles of older humans via improving satellite cell function.Frontiers in Aging Neuroscience 09/2014; 6:246. DOI:10.3389/fnagi.2014.00246 · 2.84 Impact Factor