scholarly journals Mapping of the contraction-induced phosphoproteome identifies TRIM28 as a significant regulator of skeletal muscle size and function

Cell Reports ◽  
2021 ◽  
Vol 34 (9) ◽  
pp. 108796
Author(s):  
Nathaniel D. Steinert ◽  
Gregory K. Potts ◽  
Gary M. Wilson ◽  
Amelia M. Klamen ◽  
Kuan-Hung Lin ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Size ◽  
And Function

scholarly journals Effect of increased serum 25(OH)D and calcium on structure and function of post-menopausal women: a pilot study

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
H. J. Hillstrom ◽  
R. Soeters ◽  
M. Miranda ◽  
S. I. Backus ◽  
J. Hafer ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fatigue ◽  
Repeated Measures ◽  
Vastus Lateralis ◽  
Structure And Function ◽  
Muscle Size ◽  
Menopausal Women ◽  
Post Menopausal ◽  
And Function

Abstract Summary The purpose was to determine if increasing serum 25(OH)D and calcium in postmenopausal women increased skeletal muscle size, strength, balance, and functional task performance while decreasing muscle fatigue. PCSA of the vastus lateralis increased and ascent of stairs time decreased after 6 months of increased serum 25(OH)D. Purpose The Institute of Medicine recommends ≥ 20 ng/ml of serum 25-hydroxyvitamin D [25(OH)D] for bone and overall health. Serum 25(OH)D levels have been associated with physical performance, postural sway, and falls. The purpose of this study was to determine if increasing postmenopausal women’s serum 25(OH)D levels from 20–30 ng/ml to 40–50 ng/ml improved skeletal muscle size, strength, balance, and functional performance while decreasing skeletal muscle fatigue. Methods Twenty-six post-menopausal women (60–85 years old) with baseline serum 25(OH)D levels between 20 and 30 ng/ml were recruited. Oral over-the-counter (OTC) vitamin D3 and calcium citrate were prescribed to increase subjects’ serum 25(OH)D to levels between 40 and 50 ng/ml, serum calcium levels above 9.2 mg/dl, and PTH levels below 60 pg/ml, which were confirmed at 6 and 12 weeks. Outcome measures assessed at baseline and 6 months included muscle physiological cross-sectional area (PCSA), muscle strength, postural balance, time to perform functional tasks, and muscle fatigue. Repeated measures comparisons between baseline and follow-up were performed. Results Nineteen subjects completed the study. One individual could not afford the time commitment for the repeated measures. Three individuals did not take their vitamin D as recommended. Two subjects were lost to follow-up (lack of interest), and one did not achieve targeted serum 25(OH)D. Vastus lateralis PCSA increased (p = 0.007) and ascent of stair time decreased (p = 0.042) after 6 months of increasing serum 25(OH)D levels from 20–30 ng/ml to 40–50 ng/ml. Isometric strength was unchanged. Anterior-posterior center of pressure (COP) excursion and COP path length decreased (p < 0.1) albeit non-significantly, suggesting balance may improve from increased serum 25(OH)D and calcium citrate levels. Conclusions Several measures of muscle structure and function were sensitive to elevated serum 25(OH)D and calcium levels indicating that further investigation of this phenomenon in post-menopausal women is warranted.

scholarly journals Skeletal Muscle Size, Quality And Function In Patients With Several Years After Total Hip Arthroplasty

2019 ◽  
Vol 51 (Supplement) ◽  
pp. 823
Author(s):  
Akito Yoshiko ◽  
Kohei Watanabe ◽  
Toshio Moritani ◽  
Moroe Beppu ◽  
Ryoichi Izumida ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Total Hip Arthroplasty ◽  
Hip Arthroplasty ◽  
Muscle Size ◽  
Total Hip ◽  
And Function

scholarly journals mTORC1 signaling is not essential for the maintenance of muscle mass and function in adult sedentary mice

2019 ◽  
Author(s):  
Alexander S. Ham ◽  
Kathrin Chojnowska ◽  
Lionel A. Tintignac ◽  
Shuo Lin ◽  
Alexander Schmidt ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Muscle Mass ◽  
Ex Vivo ◽  
Morphological Changes ◽  
Muscle Fibers ◽  
Protein Translation ◽  
Muscle Size ◽  
Mtorc1 Signaling ◽  
And Function

AbstractBackgroundThe balance between protein synthesis and degradation (proteostasis) is a determining factor for muscle size and function. Signaling via the mammalian target of rapamycin complex 1 (mTORC1) regulates proteostasis in skeletal muscle by affecting protein synthesis and autophagosomal protein degradation. Indeed, genetic inactivation of mTORC1 in developing and growing muscle causes atrophy resulting in a lethal myopathy. However, systemic dampening of mTORC1 signaling by its allosteric inhibitor rapamycin is beneficial at the organismal level and increases lifespan. Whether the beneficial effect of rapamycin comes at the expense of muscle mass and function is yet to be established.MethodsWe conditionally ablated the gene coding for the mTORC1-essential component raptor in muscle fibers of adult mice (iRAmKO). We performed detailed phenotypic and biochemical analyses of iRAmKO mice and compared them with RAmKO mice, which lack raptor in developing muscle fibers. We also used polysome profiling and proteomics to assess protein translation and associated signaling in skeletal muscle of iRAmKO mice.ResultsAnalysis at different time points reveal that, as in RAmKO mice, the proportion of oxidative fibers decreases, but slow-type fibers increase in iRAmKO mice. Nevertheless, no significant decrease in body and muscle mass, or muscle fiber area was detected up to 5 months post-raptor depletion. Similarly, ex vivo muscle force was not significantly reduced in iRAmKO mice. Despite stable muscle size and function, inducible raptor depletion significantly reduced the expression of key components of the translation machinery and overall translation rates.ConclusionsRaptor depletion and hence complete inhibition of mTORC1 signaling in fully-grown muscle leads to metabolic and morphological changes without inducing muscle atrophy even after 5 months. Together, our data indicate that maintenance of muscle size does not require mTORC1 signaling, suggesting that rapamycin treatment is unlikely to negatively affect muscle mass and function.

scholarly journals Effect of neuromuscular electrical stimulation on skeletal muscle size and function in patients with breast cancer receiving chemotherapy

2020 ◽  
Vol 128 (6) ◽  
pp. 1654-1665 ◽  
Author(s):  
Michael J. Toth ◽  
Thomas B. Voigt ◽  
Timothy W. Tourville ◽  
Shannon M. Prior ◽  
Blas A. Guigni ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Electrical Stimulation ◽  
Muscle Fiber ◽  
Neuromuscular Electrical Stimulation ◽  
Skeletal Muscle Fiber ◽  
Muscle Size ◽  
Fiber Types ◽  
Fiber Size ◽  
Subsarcolemmal Mitochondria ◽  
And Function

This is the first study to evaluate whether neuromuscular electrical stimulation (NMES) can be used as an exercise surrogate to improve skeletal muscle fiber size or function in cancer patients receiving treatment. We show that NMES promoted muscle fiber hypertrophy and fiber types shift but had minimal effects on single-fiber contractility and reduced subsarcolemmal mitochondria.

scholarly journals Skeletal muscle mitochondrial respiration in a model of age-related osteoarthritis is impaired after dietary rapamycin

2021 ◽  
Author(s):  
Christian J Elliehausen ◽  
Dennis M Minton ◽  
Alexander D Nichol ◽  
Adam R Konopka
Keyword(s):  
Skeletal Muscle ◽  
Mitochondrial Function ◽  
Mitochondrial Respiration ◽  
Guinea Pigs ◽  
Muscle Size ◽  
Skeletal Muscle Mitochondria ◽  
Age Related ◽  
End Stage ◽  
And Function ◽  
Permeabilized Muscle

A decline in skeletal muscle mitochondrial function is associated with the loss of skeletal muscle size and function during knee osteoarthritis (OA). We have recently reported that the 12-weeks of dietary rapamycin (Rap, 14ppm), with or without metformin (Met, 1000ppm), increased plasma glucose and OA severity in male Dunkin Hartley (DH) guinea pigs, a model of naturally occurring, age-related OA. The purpose of the current study was to determine if increased OA severity after dietary Rap and Rap+Met was accompanied by impaired skeletal muscle mitochondrial function. Mitochondrial respiration and hydrogen peroxide (H2O2) emissions were evaluated in permeabilized muscle fibers via high-resolution respirometry and fluorometry using either a saturating bolus or titration of ADP. Rap and Rap+Met decreased complex I (CI)-linked respiration and increased ADP sensitivity, consistent with previous findings in patients with end-stage OA. Rap also tended to decrease mitochondrial H2O2 emissions, however, this was no longer apparent after normalizing to respiration. The decrease in CI-linked respiration was accompanied with lower CI protein abundance. This is the first inquiry into how lifespan extending treatments Rap and Rap+Met can influence skeletal muscle mitochondria in a model of age-related OA. Collectively, our data suggest that Rap with or without Met inhibits CI-linked capacity and increases ADP sensitivity in DH guinea pigs that have greater OA severity.

scholarly journals Essential Role of Septin 7 in Skeletal Muscle Structure and Function

2020 ◽  
Vol 118 (3) ◽  
pp. 258a
Author(s):  
Laszlo Csernoch ◽  
Mónika Gönczi ◽  
Zsolt Ráduly ◽  
László Szabó ◽  
Nóra Dobrosi ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Essential Role ◽  
Structure And Function ◽  
Muscle Structure ◽  
And Function

scholarly journals Orbicularis Oculi Muscle Size and Function: Exploring the Influence of Aging and Exercise Training

Cosmetics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 29
Author(s):  
Takashi Abe ◽  
Jeremy P. Loenneke
Keyword(s):  
Older Adults ◽  
Exercise Training ◽  
Muscle Hypertrophy ◽  
Peak Velocity ◽  
Muscle Thickness ◽  
Muscle Size ◽  
Sphincter Muscle ◽  
Orbicularis Oculi Muscle ◽  
Orbicularis Oculi ◽  
And Function

The orbicularis oculi muscle is the sphincter muscle of the eyelids that blinks and closes the eyes. In this review, our aim was threefold: (1) to introduce the performance characteristics of blinking activity in young and older adults, (2) to discuss the influence of aging on the orbicularis oculi muscle in healthy adults, and (3) to provide information about the effect of facial exercise training on the orbicularis oculi muscle. To achieve the purpose of this review, a search using two electronic databases (PubMed and Scopus) and a search engine (Google Scholar) was conducted. The amplitude and peak velocity of spontaneously blinking behavior, which is an index of muscle function of the orbicularis oculi, appear to be affected by aging. The muscle thickness of the orbicularis oculi tends to be low in older adults, but there are issues that need to be examined further, such as differences in sex and measurement positions. There was no study on the effect of exercise training; however, the results of a highly trained man indicate that the orbicularis oculi muscles might elicit muscle hypertrophy through non-traditional resistance exercise.

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