Time‐course of changes in the myonuclear domain during denervation in young‐adult and old rat gastrocnemius muscle

Meer, Sander F.T. van der; Jaspers, Richard T.; Jones, David A.; Degens, Hans

doi:10.1002/mus.21822

Cited by 42 publications

(52 citation statements)

References 56 publications

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“…This could occur through an effect of SS mitochondria to modulate myonuclear number, as animal models show that SS mitochondria produce more apoptotic stimuli in response to disuse (2), and it has been suggested that loss of myonuclei contributes to muscle atrophy (4). However, we did not observe differences in myonuclei content, in keeping with recent studies showing no loss of myonuclei with disuse (9,67) or modulation of myonuclear number with variation in activity in older men (38). A more plausible mechanism may be via modulation of nuclear function.…”

Section: Discussionsupporting

confidence: 91%

Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function

Callahan

Tourville

Miller

et al. 2015

American Journal of Physiology-Cell Physiology

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Callahan DM, Tourville TW, Miller MS, Hackett SB, Sharma H, Cruickshank NC, Slauterbeck JR, Savage PD, Ades PA, Maughan DW, Beynnon BD, Toth MJ. Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function. Am J Physiol Cell Physiol 308: C932-C943, 2015. First published March 25, 2015; doi:10.1152/ajpcell.00014.2015.-In older adults, we examined the effect of chronic muscle disuse on skeletal muscle structure at the tissue, cellular, organellar, and molecular levels and its relationship to muscle function. Volunteers with advanced-stage knee osteoarthritis (OA, n ϭ 16) were recruited to reflect the effects of chronic lower extremity muscle disuse and compared with recreationally active controls (n ϭ 15) without knee OA but similar in age, sex, and health status. In the OA group, quadriceps muscle and single-fiber cross-sectional area were reduced, with the largest reduction in myosin heavy chain IIA fibers. Myosin heavy chain IIAX fibers were more prevalent in the OA group, and their atrophy was sex-specific: men showed a reduction in crosssectional area, and women showed no differences. Myofibrillar ultrastructure, myonuclear content, and mitochondrial content and morphology generally did not differ between groups, with the exception of sex-specific adaptations in subsarcolemmal (SS) mitochondria, which were driven by lower values in OA women. SS mitochondrial content was also differently related to cellular and molecular functional parameters by sex: greater SS mitochondrial content was associated with improved contractility in women but reduced function in men.Collectively, these results demonstrate sex-specific structural phenotypes at the cellular and organellar levels with chronic disuse in older adults, with novel associations between energetic and contractile systems. mitochondria; physical activity; ultrastructure; myosin AGING AND DISEASE are frequently accompanied by reduced functional capacity and the development of physical disability (18). Reductions in physical activity with age are well documented (28,60,68) and promote chronic disease (31,44,53) and disability. As a result of their temporal coordination, it is difficult to disentangle the relative influence of age, disease, and physical inactivity on skeletal muscle biology and, in turn, the progression toward physical disability. Indeed, many of the muscle phenotypes that accompany aging and chronic disease, such as atrophy and contractile dysfunction, closely mimic those that accompany muscle disuse (1,46). Whether developed gradually or rapidly following a clinical event, muscle disuse in chronic conditions, such as heart failure or chronic obstructive pulmonary disease, is characterized by its persistent nature, as numerous studies reveal reduced habitual activity levels in these populations (28,60,68). Our understanding of the effects of chronic disuse on skeletal muscle size and structure is limited, in part, by the fact that it would be unethical to experimentally impose ...

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Section: Discussionsupporting

confidence: 91%

Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function

Callahan

Tourville

Miller

et al. 2015

American Journal of Physiology-Cell Physiology

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“…As we observed previously [34], the similar muscle mass but larger fibre cross-sectional area in older Gm suggests that the number of fibres was reduced during ageing. This might be the result of an incomplete denervation-reinnervation process leading to loss of fibres [35] and compensatory hypertrophy of the remaining fibres.…”

Section: Effects Of Ageingsupporting

confidence: 86%

Effects of alfacalcidol on circulating cytokines and growth factors in rat skeletal muscle

et al. 2011

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Supra-physiological levels of vitamin D induce skeletal muscle atrophy, which may be particularly detrimental in already sarcopaenic elderly. Neither the cause nor whether the atrophy is fibre type specific are known. To obtain supraphysiological levels of circulating vitamin D (1,25(OH) 2 D 3 ) 27.5-month-old female Fischer 344 9 Brown Norway F1 rats were orally treated for 6 weeks with vehicle or the vitamin D analogue alfacalcidol. Alfacalcidol treatment induced a 22% decrease in body mass and 17% muscle atrophy. Fibre atrophy was restricted to type IIb fibres in the low-oxidative part of the gastrocnemius medialis only (-22%; P \ 0.05). There was a concomitant 1.6-fold increase in mRNA expression of the ubiquitin ligase MuRF-1 (P \ 0.001), whereas those of insulin-like growth factor 1 and myostatin were not affected. Circulating IL-6 was unaltered, but leptin and adiponectin were decreased (-39%) and increased (64%), respectively. The treated rats also exhibited a reduced food intake. In conclusion, supraphysiological levels of circulating 1,25(OH) 2 D 3 cause preferential atrophy of type IIb fibres, which is associated with an increased expression of MuRF-1 without evidence of systemic inflammation. The atrophy and loss of body mass in the presence of supra-physiological levels of vitamin D are primarily due to a reduced food intake.

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“…Sections were co-stained with DAPI and anti-Pax7 antibody according to (van der Meer et al, 2011b). Briefly, sections were fixed in 4% formaldehyde PBS for 10 min, washed with PBST and blocked in 10% normal donkey serum (NDS) in PBS for 30 min.…”

Section: Quantification Of Myonuclei and Sc Numbermentioning

confidence: 99%

Blunted hypertrophic response in old mouse muscle is associated with a lower satellite cell density and is not alleviated by resveratrol

Ballak

Jaspers

Deldicque

et al. 2015

Experimental Gerontology

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Background: Sarcopenia contributes to the decreased quality of life in the older person.While resistance exercise is an effective measure to increase muscle mass and strength, the hypertrophic response may be blunted in old age.Objectives: To determine 1) whether hypertrophy in the m. plantaris of old mice was blunted compared to adult and 2) whether this was related to a reduced satellite cell (SC) density and 3) how resveratrol affects hypertrophy in old mice. Methods:In adult (7.5 months, n=11), old (23.5 months, n=10) and old-resveratrol-treated (n=10) male C57BL/6j mice, hypertrophy of the left m. plantaris was induced by denervation of its synergists. The contralateral leg served as control.Results: After six weeks, overload-induced myofiber hypertrophy and IIB-IIA shift in myofiber type composition were less pronounced in old than adult mice (P=0.03), irrespective of resveratrol treatment. Muscles from old mice had a lower SC density than adult muscles (P=0.002). Overload-induced SC proliferation (P<0.05) resulted in an increased SC density in old, but not adult muscles (P=0.02), while a decrease occurred after resveratrol supplementation (P=0.044). Id2 and myogenin protein expression levels were higher in old than adult muscles (P<0.05). Caspase-3 was expressed more in hypertrophied than control muscles and was reduced with resveratrol (P<0.05). Conclusion:The blunted hypertrophic response in old mice was associated with a lower SC density, but there was no evidence for a lower capacity for proliferation. Resveratrol did not rescue the hypertrophic response and even reduced, rather than increased, the number of SCs in hypertrophied muscles.

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Time‐course of changes in the myonuclear domain during denervation in young‐adult and old rat gastrocnemius muscle

Cited by 42 publications

References 56 publications

Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function

Chronic disuse and skeletal muscle structure in older adults: sex-specific differences and relationships to contractile function

Effects of alfacalcidol on circulating cytokines and growth factors in rat skeletal muscle

Blunted hypertrophic response in old mouse muscle is associated with a lower satellite cell density and is not alleviated by resveratrol

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