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skeletal muscle and exercise

Yuri Ishiuchi, Hitoshi Sato, Narumi Komatsu, Hideo Kawaguchi, Takashi Matsuwaki, Keitaro Yamanouchi, Masugi Nishihara, Taku Nedachi
Skeletal muscle is an endocrine organ that secretes several proteins, which are collectively termed myokines. Although many studies suggest that exercise regulates myokine secretion, the underlying mechanisms remain unclear and all the exercise-dependent myokines have not yet been identified. Therefore, in this study, we attempted to identify novel exercise-dependent myokines by using our recently developed in vitro contractile model. Differentiated C2C12 myotubes were cultured with or without electrical pulse stimulation (EPS) for 24 h to induce cell contraction, and the myokines secreted in conditioned medium were analyzed using a cytokine array...
March 17, 2018: Cytokine
Takahiro Maekawa, Riki Ogasawara, Arata Tsutaki, Kihyuk Lee, Satoshi Nakada, Koichi Nakazato, Naokata Ishii
High-intensity exercise has recently been shown to cause an increase in brain-derived neurotropic factor (BDNF) in the hippocampus. Some studies have suggested that myokines secreted from contracting skeletal muscle, such as irisin (one of the truncated form of fibronectin type III domain-containing protein 5 (FNDC5)), play important roles in this process. Thus, we hypothesized that locally evoked muscle contractions may cause an increase of BDNF in the hippocampus through some afferent mechanisms. Under anesthesia, Sprague-Dawley rats were fixed on a custom-made dynamometer and their triceps surae muscles were made to maximally contract via delivery of electric stimulations of the sciatic nerve (100 Hz with 1-ms pulse and 3-s duration)...
March 20, 2018: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Baubak Shamim, John A Hawley, Donny M Camera
Human skeletal muscle satellite cells are activated in response to both resistance and endurance exercise. It was initially proposed that satellite cell proliferation and differentiation were only required to support resistance exercise-induced hypertrophy. However, satellite cells may also play a role in muscle fibre remodelling after endurance-based exercise and extracellular matrix regulation. Given the importance of dietary protein, particularly branched chain amino acids, in supporting myofibrillar and mitochondrial adaptations to both resistance and endurance-based training, a greater understanding of how protein intake impacts satellite cell activity would provide further insight into the mechanisms governing skeletal muscle remodelling with exercise...
March 20, 2018: Sports Medicine
Carole Mast, Dominique Dardevet, Isabelle Papet
The optimisation of nutritional support for the growing number of older individuals does not usually take into account medication. Paracetamol (acetaminophen; APAP) is the first intention treatment of chronic pain that is highly prevalent and persistent in the elderly. Detoxification of APAP occurs in the liver and utilises sulfate and glutathione (GSH), both of which are issued from cysteine (Cys), a conditionally indispensable amino acid. The detoxification-induced siphoning of Cys could reduce the availability of Cys for skeletal muscle...
March 20, 2018: Nutrition Research Reviews
Ryan Rosenberry, Susie Chung, Michael D Nelson
Exercise represents a major hemodynamic stress that demands a highly coordinated neurovascular response in order to match oxygen delivery to metabolic demand. Reactive hyperemia (in response to a brief period of tissue ischemia) is an independent predictor of cardiovascular events and provides important insight into vascular health and vasodilatory capacity. Skeletal muscle oxidative capacity is equally important in health and disease, as it determines the energy supply for myocellular processes. Here, we describe a simple, non-invasive approach using near-infrared spectroscopy to assess each of these major clinical endpoints (reactive hyperemia, neurovascular coupling, and muscle oxidative capacity) during a single clinic or laboratory visit...
February 20, 2018: Journal of Visualized Experiments: JoVE
Qun Zuo, Shu-Chen Wang, Xin-Kai Yu, Wei-Wei Chao
PURPOSE: Macrophages are known to be important for healing numerous injured tissues depending on their functional phenotypes in response to different stimuli. The objective of this study was to reveal macrophage phenotypic changes involved in exercise-induced skeletal muscle injury and regeneration. METHODS: Adult male Sprague-Dawley rats experienced one session of downhill running (16° decline, 16 m/min) for 90 min. After exercise the blood and soleus muscles were collected at 0 h, 6 h, 12 h, 1 d, 2 d, 3 d, 1 w and 2 w after exercise, separately...
February 20, 2018: Chinese Journal of Traumatology, Zhonghua Chuang Shang za Zhi
Chris Chin Wah Chen, Avigail T Erlich, David A Hood
BACKGROUND: Parkin is a ubiquitin ligase that is involved in the selective removal of dysfunctional mitochondria. This process is termed mitophagy and can assist in mitochondrial quality control. Endurance training can produce adaptations in skeletal muscle toward a more oxidative phenotype, an outcome of enhanced mitochondrial biogenesis. It remains unknown whether Parkin-mediated mitophagy is involved in training-induced increases in mitochondrial content and function. Our purpose was to determine a role for Parkin in maintaining mitochondrial turnover in muscle, and its requirement in mediating mitochondrial biogenesis following endurance exercise training...
March 17, 2018: Skeletal Muscle
Saskia Reibe, Marit Hjorth, Mark A Febbraio, Martin Whitham
Exercise stimulates a wide array of biological processes, but the mechanisms involved are incompletely understood. Many previous studies have adopted transcriptomic analyses of skeletal muscle to address particular research questions, a process that ultimately results in the collection of large amounts of publicly available data that has not been fully integrated or interrogated. To maximize the use of these available transcriptomic exercise data sets, we have downloaded and re-analyzed them and formulated the data into a searchable online tool, geneXX...
March 16, 2018: Physiological Genomics
Zhong-Min Wang, Xiaoyan Leng, María Laura Messi, Seung J Choi, Anthony P Marsh, Barbara Nicklas, Osvaldo Delbono
Background: Previous studies support beneficial effects of both resistance exercise training (RT) and caloric restriction (CR) on skeletal muscle strength and physical performance. The goal of this study was to determine the effects of adding CR to RT on single-muscle fiber contractility responses to RT in older overweight and obese adults. Methods: We analyzed contractile properties in 1,253 single myofiber from muscle biopsies of the vastus lateralis, as well as physical performance and thigh muscle volume, in 31 older (65-80 yrs), overweight or obese (body mass index= 27-35 kg/m2) men (n=19) and women (n=12) who were randomly assigned to a standardized, progressive RT intervention with CR (RT+CR; n=15) or without CR (RT; n=16) for 5 months...
March 13, 2018: Journals of Gerontology. Series A, Biological Sciences and Medical Sciences
Jared M Dickinson, Andrew C D'Lugos, Marcus A Naymik, Ashley L Siniard, Amanda J Wolfe, Donald P Curtis, Matthew J Huentelman, Chad C Carroll
Aerobic (AE) and resistance exercise (RE) elicit unique adaptations in skeletal muscle that have distinct implications for health and performance. The purpose of this study was to identify the unique transcriptome response of skeletal muscle to acute AE and RE. In a counter-balanced, cross-over design, six healthy, recreationally active young men (27{plus minus}3y) completed acute AE (40 min cycling, ~70% maximal HR) and RE (8 sets, 10 reps, ~65% 1RM), separated by ~1wk. Muscle biopsies ( vastus lateralis) were obtained before and at 1 and 4h post exercise...
March 15, 2018: Journal of Applied Physiology
Boe M Burrus, Brian M Moscicki, Tracey D Matthews, Vincent J Paolone
Chronic supplementation of L-carnitine and carbohydrate has been reported to increase L-carnitine content in skeletal muscle and have positive influences on exercise variables and performance. This study investigated the acute intake of L-carnitine and carbohydrate on the exercise parameters of cycling. A total of 10 males (27.0 ± 4 years) completed two exercise sessions consisting of 40 min of cycling at 65% of VO2peak , followed by cycling to exhaustion at 85% of VO2peak . L-carnitine or a placebo was consumed 3 hours prior to exercise, and beverages consisting of 94 g of carbohydrate were consumed at both 2 hours, and 30 minutes prior to exercise...
2018: International Journal of Exercise Science
Graham P Holloway, Andrew M Holwerda, Paula M Miotto, Marlou L Dirks, Lex B Verdijk, Luc J C van Loon
It remains unknown if mitochondrial bioenergetics are altered with aging in humans. We established an in vitro method to simultaneously determine mitochondrial respiration and H2 O2 emission in skeletal muscle tissue across a range of biologically relevant ADP concentrations. Using this approach, we provide evidence that, although the capacity for mitochondrial H2 O2 emission is not increased with aging, mitochondrial ADP sensitivity is impaired. This resulted in an increase in mitochondrial H2 O2 and the fraction of electron leak to H2 O2 , in the presence of virtually all ADP concentrations examined...
March 13, 2018: Cell Reports
Mackenzie Haines, Sarah K McKinley-Barnard, Thomas L Andre, Josh J Gann, Paul S Hwang, Darryn S Willoughby
This study sought to determine if the differences in serum estradiol we have previously observed to occur during the mid-follicular (MF) and mid-luteal (ML) phases of the female menstrual cycle could be attributed to estrogen-induced receptor activation and subsequent effects on myogenic-related genes which may otherwise impact muscle regeneration in response to eccentric exercise. Twenty-two physically-active females (20.9 ± 1.4 years, 63.5 ± 9.0 kg, 1.65 ± 0.08 m) underwent an eccentric exercise bout of the knee extensors during the MF and ML phases of their 28-day menstrual cycle...
March 2018: Journal of Sports Science & Medicine
José V Subiela, Sonia H Torres, Juan B De Sanctis, Noelina Hernández
There is evidence that myocardial infarction (MI) patients have an inflammatory process that includes skeletal muscles, and exercise has been reported to reduce some inflammatory markers. The aim of this work was to study NO and some inflammatory markers in quadriceps muscle of MI patients before and after cardiac rehabilitation. Muscle biopsy was obtained in17 MI patients before and after CR and only once in 11 healthy subjects. Several cardiorespiratory and metabolic parameters were evaluated and skeletal muscle levels of nitric oxide synthases, nitrate, nitrite, nitrotyrosine, tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), interleukin- 6 (IL-6) and CD154...
March 10, 2018: Nitric Oxide: Biology and Chemistry
Alberto A Castro, Theodore Garland
We have used selective breeding with house mice to study coadaptation of morphology and physiology with the evolution of high daily levels of voluntary exercise. Here, we compared hindlimb bones and muscle masses from the 11th generation of four replicate High Runner (HR) lines of house mice bred for high levels of voluntary wheel running with four non-selected control (C) lines. Mass, length, diameter, and depth of the femur, tibia-fibula, and metatarsal bones, as well as masses of gastrocnemius and quadriceps muscles, were compared by analysis of covariance with body mass or body length as the covariate...
March 13, 2018: Journal of Morphology
Deana Haralampieva, Souzan Salemi, Thomas Betzel, Ivana Dinulovic, Stefanie D Krämer, Roger Schibli, Tullio Sulser, Christoph Handschin, Simon M Ametamey, Daniel Eberli
While many groups demonstrated new muscle tissue formation after muscle precursor cell (MPC) injection, the capacity of these cells to heal muscle damage, for example, sphincter in stress urinary incontinence, in long-term is still limited. Therefore, the first goal of our project was to optimize the functional regenerative potential of hMPC by genetic modification to overexpress human peroxisome proliferator-activated receptor gamma coactivator 1-alpha (hPGC-1 α ), key regulator of exercise-mediated adaptation...
2018: Stem Cells International
Jessica M Scott, Tormod S Nilsen, Dipti Gupta, Lee W Jones
Cardio-oncology is an emerging discipline focused predominantly on the detection and management of cancer treatment-induced cardiac dysfunction (cardiotoxicity), which predisposes to development of overt heart failure or coronary artery disease. The direct adverse consequences, as well as those secondary to anticancer therapeutics, extend beyond the heart, however, to affect the entire cardiovascular-skeletal muscle axis (ie, whole-organism cardiovascular toxicity). The global nature of impairment creates a strong rationale for treatment strategies that augment or preserve global cardiovascular reserve capacity...
March 13, 2018: Circulation
Sinead T J Mcdonagh, Lee J Wylie, Christopher Thompson, Anni Vanhatalo, Andrew M Jones
This article provides an overview of the current literature relating to the efficacy of dietary nitrate (NO3 - ) ingestion in altering aspects of cardiovascular and metabolic health and exercise capacity in healthy and diseased individuals. The consumption of NO3 - -rich vegetables, such as spinach and beetroot, have been variously shown to promote nitric oxide bioavailability, reduce systemic blood pressure, enhance tissue blood flow, modulate muscle O2 utilisation and improve exercise tolerance both in normoxia and in hypoxia, as is commonly observed in a number of disease states...
March 13, 2018: European Journal of Sport Science
Irina Kramerova, Jorge A Torres, Ascia Eskin, Stanley F Nelson, Melissa J Spencer
Mutations in CAPN3 cause autosomal recessive limb girdle muscular dystrophy 2A. Calpain 3 (CAPN3) is a calcium dependent protease residing in the myofibrillar, cytosolic and triad fractions of skeletal muscle. At the triad, it colocalizes with calcium calmodulin kinase IIβ (CaMKIIβ). CAPN3 knock out mice (C3KO) show reduced triad integrity and blunted CaMKIIβ signaling, which correlates with impaired transcriptional activation of myofibrillar and oxidative metabolism genes in response to running exercise...
March 8, 2018: Human Molecular Genetics
F M Gür, S Timurkaan, B Gençer Tarakçi, M H Yalçin, Z E Özkan, S B Baygeldi, S Yilmaz, H Eröksüz
Irisin is mainly secreted by heart and skeletal muscle cells. It is an exercise-induced protein that converts white adipose tissue to brown. Increased irisin expression was lead to weight loss and improved glucose tolerance. We investigated irisin immunoreactivity in various tissues of the dwarf hamsters (Phodopus roborovskii). Tissues were processed, embedded in paraffin, sectioned at 5 μm and stained immunohistochemically for irisin. In the retina, irisin was found almost all layers, except outer nuclear layer...
April 2018: Anatomia, Histologia, Embryologia
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