Skeletal muscle morphology and regulatory signalling in endurance-trained and sedentary individuals: The influence of ageing

Mikkelsen, Ulla Ramer; Agergaard, Jakob; Couppé, Christian; Grosset, J.; Karlsen, Anders; Magnusson, S. Peter; Schjerling, Peter; Kjær, Michael; Mackey, Abigail L.

doi:10.1016/j.exger.2017.04.001

Cited by 40 publications

(26 citation statements)

References 57 publications

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“…Sarcopenic mice display no change in nuclear or total FOXO3 protein expression despite reduced phosphorylation levels that might be indicative of higher FOXO3 activity 30 . We and others showed that FOXO3 mRNA 31, 32 and FOXO3 nuclear protein levels decreased in old human skeletal muscle 33 whereas total or phosphorylated FOXO3 protein expression did not change 34 . It is generally accepted that sarcopenia cannot be attributed to an upregulation of the proteolytic system or an induction of FOXO3 35 .…”

Section: Foxo3 and The Regulation Of Skeletal Muscle Homeostasismentioning

confidence: 60%

Recent advances in understanding the role of FOXO3

et al. 2018

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The forkhead box O3 (FOXO3, or FKHRL1) protein is a member of the FOXO subclass of transcription factors. FOXO proteins were originally identified as regulators of insulin-related genes; however, they are now established regulators of genes involved in vital biological processes, including substrate metabolism, protein turnover, cell survival, and cell death. FOXO3 is one of the rare genes that have been consistently linked to longevity in in vivo models. This review provides an update of the most recent research pertaining to the role of FOXO3 in (i) the regulation of protein turnover in skeletal muscle, the largest protein pool of the body, and (ii) the genetic basis of longevity. Finally, it examines (iii) the role of microRNAs in the regulation of FOXO3 and its impact on the regulation of the cell cycle.

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Section: Foxo3 and The Regulation Of Skeletal Muscle Homeostasismentioning

confidence: 60%

Recent advances in understanding the role of FOXO3

et al. 2018

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“…The apparently increased density of MFBs in the perimysium (Figure 3), which was unexpectedly observed in this study, could be of clinical significance. In food science, meat toughness correlates with perimysial thickness (Bendall, 1967; Rowe, 1974) and aging recently has been found to be paralleled by an increased complexity in the organization of the perimysium (Mikkelsen et al, 2017). Since an augmented perimysial collagen density has been observed in tonic muscles as opposed to a lower density in more phasic muscles (An et al, 2014; Roy et al, 2018), this suggests that a related perimysial stiffening may indeed contribute to myofascial tonicity in human erector spinae muscles, and particularly to the deep multifidus layer (Mannion et al, 1997; MacDonald et al, 2006).…”

Section: Discussionmentioning

confidence: 99%

Fascia Is Able to Actively Contract and May Thereby Influence Musculoskeletal Dynamics: A Histochemical and Mechanographic Investigation

et al. 2019

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Fascial tissues form a ubiquitous network throughout the whole body, which is usually regarded as a passive contributor to biomechanical behavior. We aimed to answer the question, whether fascia may possess the capacity for cellular contraction which, in turn, could play an active role in musculoskeletal mechanics. Human and rat fascial specimens from different body sites were investigated for the presence of myofibroblasts using immunohistochemical staining for α-smooth muscle actin ( n = 31 donors, n = 20 animals). In addition, mechanographic force registrations were performed on isolated rat fascial tissues ( n = 8 to n = 18), which had been exposed to pharmacological stimulants. The density of myofibroblasts was increased in the human lumbar fascia in comparison to fasciae from the two other regions examined in this study: fascia lata and plantar fascia [ H (2) = 14.0, p < 0.01]. Mechanographic force measurements revealed contractions in response to stimulation by fetal bovine serum, the thromboxane A2 analog U46619, TGF-β1, and mepyramine, while challenge by botulinum toxin type C3–used as a Rho kinase inhibitor– provoked relaxation ( p < 0.05). In contrast, fascial tissues were insensitive to angiotensin II and caffeine ( p < 0.05). A positive correlation between myofibroblast density and contractile response was found ( r s = 0.83, p < 0.001). The hypothetical application of the registered forces to human lumbar tissues predicts a potential impact below the threshold for mechanical spinal stability but strong enough to possibly alter motoneuronal coordination in the lumbar region. It is concluded that tension of myofascial tissue is actively regulated by myofibroblasts with the potential to impact active musculoskeletal dynamics.

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“…In this respect, density of muscle derived from computed tomography has been inversely associated with body fat, fat infiltration of muscle, and muscle strength and function. 8,20 Whether sedentary behavior independently contributes to loss of muscle density is unknown, but recent evidence suggests that sedentary behavior is independently associated with reduced muscle strength and functional performance. [4][5][6] Our study adds to the understanding of the detrimental effects of sedentary behavior on skeletal muscle health and is the first to demonstrate leisure sedentary behavior is associated with skeletal muscle density independent of MVPA.…”

Section: Discussionmentioning

confidence: 99%

Associations of Sedentary Behavior and Abdominal Muscle Density: The Multi-Ethnic Study of Atherosclerosis

Vella¹,

Michos²,

Sears³

et al. 2018

Journal of Physical Activity and Health

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Background: Sedentary behaviors (SB) may exacerbate loss of muscle mass and function, independent of physical activity levels. This study examined the associations of SB with abdominal muscle area and density, a marker of muscle quality, in adults. Methods: A total of 1895 participants from the Multi-Ethnic Study of Atherosclerosis completed detailed health history, physical activity and SB questionnaires, computed tomography to quantify body composition, and measurements of inflammatory markers. Analyses included linear and nonlinear regression. Results: The mean age and body mass index were 64.6 years and 28 kg·m−2, respectively, and 50% were women. On average, participants engaged in 28 metabolic equivalent hours·week−1 of SB. With adjustment for age, sex, race/ethnicity, physical activity, cardiovascular disease risk factors, and inflammation, multivariable regression modeling revealed a nonlinear (quadratic) relationship between SB and locomotor, stability, and total abdominal muscle density (P < .01) but not muscle area. The SB inflection point at which locomotor, stability, and total abdominal muscle density began to decrease was 38.2, 39.6, and 39.2 metabolic equivalent hours·week−1 of SB, respectively. Conclusions: SB is associated with reduced muscle density when practiced as little as 5.5 metabolic equivalent hours·day−1. These findings may have important implications for SB guidelines for targeting skeletal muscle health in older adults.

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Skeletal muscle morphology and regulatory signalling in endurance-trained and sedentary individuals: The influence of ageing

Cited by 40 publications

References 57 publications

Recent advances in understanding the role of FOXO3

Recent advances in understanding the role of FOXO3

Fascia Is Able to Actively Contract and May Thereby Influence Musculoskeletal Dynamics: A Histochemical and Mechanographic Investigation

Associations of Sedentary Behavior and Abdominal Muscle Density: The Multi-Ethnic Study of Atherosclerosis

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