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Special Issue "Regulation of Muscle Mass, Exercise, Metabolism"

Special Issue Editor

Dr. Joseph Marino
E-Mail Website
Guest Editor
Department of Applied Physiology, Health, and Clinical Sciences, The University of North Carolina at Charlotte, Charlotte, NC 28223-0001, USA
Interests: obesity; diabetes; exercise; skeletal muscle

Special Issue Information

Dear Colleagues,

I am pleased to announce that a Special Issue on The Regulation of Skeletal Muscle Mass and Metabolism in Health and Disease is being organized by the Journal of Environmental Research and Public Health. Skeletal muscle has the remarkable ability to adapt to an array of stressors that result in altered structure, function, and metabolism. When such adaptations occur in response to exercise and other healthy lifestyle habits, these adaptations are favorable and enhance quality of life. However, skeletal muscle structure, function, and metabolism may also be altered directly in response to certain disease states, or indirectly as a result of disease treatment. Oftentimes, this results in loss of skeletal muscle mass, poor metabolic control, and reduced quality of life. Developing strategies to improve skeletal muscle health during disease will improve patient outcomes and reduce the health care burden. The keywords below provide some of the areas of interest.

Dr. Joseph Marino
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2300 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Cachexia
  • Sarcopenia
  • Exercise
  • Metabolic disease
  • Muscle hypertrophy
  • Muscle atrophy
  • Epigenetics
  • Epidemiology
  • Disease prevention
  • Disuse/Bed rest
  • Corticosteroid treatment

Published Papers (13 papers)

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Research

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Article
Impact of Vitamin B12 Insufficiency on Sarcopenia in Community-Dwelling Older Korean Adults
by , , , , , , , , , , , and
Int. J. Environ. Res. Public Health 2021, 18(23), 12433; https://doi.org/10.3390/ijerph182312433 (registering DOI) - 26 Nov 2021
Viewed by 174
Abstract
Vitamin B12 (B12) is involved as a cofactor in the synthesis of myelin. A lack of B12 impairs peripheral nerve production, which can contribute to sarcopenia. In this cross-sectional study, we aimed to investigate the relationship between B12 insufficiency and sarcopenia in community-dwelling [...] Read more.
Vitamin B12 (B12) is involved as a cofactor in the synthesis of myelin. A lack of B12 impairs peripheral nerve production, which can contribute to sarcopenia. In this cross-sectional study, we aimed to investigate the relationship between B12 insufficiency and sarcopenia in community-dwelling older Korean adults. A total of 2325 (1112 men; 1213 women) adults aged 70–84 years were recruited. The tools used for sarcopenia were based on the Asian Working Group for Sarcopenia (AWGS) guidelines. Individuals with low appendicular skeletal muscle mass index (ASMI) (<7.0 kg/m2 for men; <5.4 kg/m2 for women) and low hand grip strength (HGS) (<28 kg for men; <18 kg for women) were defined as the sarcopenia group. Among this group, those who showed low physical performance (≤9 points on the Short Physical Performance Battery (SPPB)) were defined as the severe sarcopenia group. B12 concentrations were classified into insufficient (<350 pg/mL) and sufficient (≥350 pg/mL). Univariate and multivariate logistic regression analyses were used to evaluate the relationship between sarcopenia and B12 levels. Low ASMI showed a high incidence in the B12-insufficient group. However, HGS, SPPB, and the severity of sarcopenia showed no correlation with B12. Further, insufficient B12 may affect muscle quantity rather than muscle strength or physical performance. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Association between Adjusted Handgrip Strength and Metabolic Syndrome in Arab Men
Int. J. Environ. Res. Public Health 2021, 18(20), 10898; https://doi.org/10.3390/ijerph182010898 - 17 Oct 2021
Viewed by 400
Abstract
This cross-sectional study determined the association between handgrip strength (HGS) and metabolic syndrome (MetS) in Arab men. Furthermore, HGS and adjusted HGS, relative to body composition components including body mass index (BMI), body weight, and body fat percentage (%Fat), were examined in predicting [...] Read more.
This cross-sectional study determined the association between handgrip strength (HGS) and metabolic syndrome (MetS) in Arab men. Furthermore, HGS and adjusted HGS, relative to body composition components including body mass index (BMI), body weight, and body fat percentage (%Fat), were examined in predicting MetS. Methods: In this study, 854 men participated in and completed all tests (age, 39.7 ± 15.2 years; BMI, 28.4 ± 5.2 kg/m2; %Fat, 26.6% ± 7.1%). Body composition and HGS were measured using a body impedance analyzer and a manual spring-type dynamometer, respectively. About 10 cc of venous blood was drawn once after overnight fasting and analyzed using the colorimetric method. MetS included waist circumference (WC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), blood pressure (BP), and fasting glucose were defined for the current specific population. Results: The receiver operating characteristics curve (ROC curve) showed an area under the curve (AUC) of HGS = 0.54, and 0.70 for HGS/%Fat. Linear regression analysis showed that the R2 values for all three models were low in predicting MetS and its components. Lastly, the odds ratio of adjusted HGS showed that there were significant differences between all quartiles of MetS compared with the reference quartile (Q1), whereas HGS alone did not show such differences. A significant difference between the quartiles of HGS and adjusted HGS was observed in Q4 for glucose, and significant differences were also found from Q2 for hypertension in terms of the HGS and adjusted HGS. Conclusion: HGS could have protective potential for increased levels of glucose and systolic blood pressure, and using adjusted HGS rather than HGS alone is recommended for the association of MetS in Arab men. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Effect of Resonant Frequency Vibration on Delayed Onset Muscle Soreness and Resulting Stiffness as Measured by Shear-Wave Elastography
Int. J. Environ. Res. Public Health 2021, 18(15), 7853; https://doi.org/10.3390/ijerph18157853 - 24 Jul 2021
Viewed by 853
Abstract
This study utilized resonant frequency vibration to the upper body to determine changes in pain, stiffness and isometric strength of the biceps brachii after eccentric damage. Thirty-one participants without recent resistance training were randomized into three groups: a Control (C) group and two [...] Read more.
This study utilized resonant frequency vibration to the upper body to determine changes in pain, stiffness and isometric strength of the biceps brachii after eccentric damage. Thirty-one participants without recent resistance training were randomized into three groups: a Control (C) group and two eccentric exercise groups (No vibration (NV) and Vibration (V)). After muscle damage, participants in the V group received upper body vibration (UBV) therapy for 5 min on days 1–4. All participants completed a visual analog scale (VAS), maximum voluntary isometric contraction (MVIC), and shear wave elastography (SWE) of the bicep at baseline (pre-exercise), 24 h, 48 h, and 1-week post exercise. There was a significant difference between V and NV at 24 h for VAS (p = 0.0051), at 24 h and 1-week for MVIC (p = 0.0017 and p = 0.0016, respectively). There was a significant decrease in SWE for the V group from 24–48 h (p = 0.0003), while there was no significant change in the NV group (p = 0.9341). The use of UBV resonant vibration decreased MVIC decrement and reduced VAS pain ratings at 24 h post eccentric damage. SWE was strongly negatively correlated with MVIC and may function as a predictor of intrinsic muscle state in the time course of recovery of the biceps brachii. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Metabolic and Molecular Subacute Effects of a Single Moderate-Intensity Exercise Bout, Performed in the Fasted State, in Obese Male Rats
Int. J. Environ. Res. Public Health 2021, 18(14), 7543; https://doi.org/10.3390/ijerph18147543 - 15 Jul 2021
Cited by 1 | Viewed by 949
Abstract
Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment [...] Read more.
Introduction and objectives: Obesity represents a major global public health problem. Its etiology is multifactorial and includes poor dietary habits, such as hypercaloric and hyperlipidic diets (HFDs), physical inactivity, and genetic factors. Regular exercise is, per se, a tool for the treatment and prevention of obesity, and recent studies suggest that the beneficial effects of exercise can be potentiated by the fasting state, thus potentially promoting additional effects. Despite the significant number of studies showing results that corroborate such hypothesis, very few have evaluated the effects of fasted-state exercise in overweight/obese populations. Therefore, the aim of this study was to evaluate the subacute effects (12 h after conclusion) of a single moderate-intensity exercise bout, performed in either a fed or an 8 h fasted state, on serum profile, substrate-content and heat shock pathway–related muscle protein immunocontent in obese male rats. Methods: Male Wistar rats received a modified high-fat diet for 12 weeks to induce obesity and insulin resistance. The animals were allocated to four groups: fed rest (FER), fed exercise (FEE), fasted rest (FAR) and fasted exercise (FAE). The exercise protocol was a 30 min session on a treadmill, with an intensity of 60% of VO2max. The duration of the fasting period was 8 h prior to the exercise session. After a 12 h recovery, the animals were killed and metabolic parameters of blood, liver, heart, gastrocnemius and soleus muscles were evaluated, as well as SIRT1 and HSP70 immunocontent in the muscles. Results: HFD induced obesity and insulin resistance. Soleus glycogen concentration decreased in the fasted groups and hepatic glycogen decreased in the fed exercise group. The combination of exercise and fasting promoted a decreased concentration of serum total cholesterol and triglycerides. In the heart, combination fasting plus exercise was able to decrease triglycerides to control levels. In the soleus muscle, both fasting and fasting plus exercise were able to decrease triglyceride concentrations. In addition, heat shock protein 70 and sirtuin 1 immunocontent increased after exercise in the gastrocnemius and soleus muscles. Conclusions: An acute bout of moderate intensity aerobic exercise, when realized in fasting, may induce, in obese rats with metabolic dysfunctions, beneficial adaptations to their health, such as better biochemical and molecular adaptations that last for at least 12 h. Considering the fact that overweight/obese populations present an increased risk of cardiovascular events/diseases, significant reductions in such plasma markers of lipid metabolism are an important achievement for these populations. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
The Effect of Polarized Training (SIT, HIIT, and ET) on Muscle Thickness and Anaerobic Power in Trained Cyclists
Int. J. Environ. Res. Public Health 2021, 18(12), 6547; https://doi.org/10.3390/ijerph18126547 - 18 Jun 2021
Viewed by 972
Abstract
This study was undertaken to investigate the effect of two different concepts in a training program on muscle thickness and anaerobic power in trained cyclists. Twenty-six mountain bike cyclists participated in the study and were divided into an experimental group (E), which performed [...] Read more.
This study was undertaken to investigate the effect of two different concepts in a training program on muscle thickness and anaerobic power in trained cyclists. Twenty-six mountain bike cyclists participated in the study and were divided into an experimental group (E), which performed polarized training, comprising sprint interval training (SIT), high-intensity interval training (HIIT), and endurance training (ET), and a control group (C), which performed HIIT and ET. The experiment was conducted over the course of 9 weeks. Laboratory tests were performed immediately before and after the conducted experiment, including an ultrasound measurement of the quadriceps femoris muscle thickness and a sprint interval testing protocol (SITP). During the SITP, the cyclists performed 4 maximal repetitions, 30 s each, with a 90-s rest period between the repetitions. SITP was performed to measure maximal and mean anaerobic power. As a result of the applied training program, the muscle thickness decreased and the mean anaerobic power increased in the experimental group. By contrast, no significant changes were observed in the control group. In conclusion, a decrease in muscle thickness with a concomitant increase in mean anaerobic power resulting from the polarized training program is beneficial in mountain bike cycling. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Association of Lumbar Paraspinal Muscle Morphometry with Degenerative Spondylolisthesis
Int. J. Environ. Res. Public Health 2021, 18(8), 4037; https://doi.org/10.3390/ijerph18084037 - 12 Apr 2021
Viewed by 795
Abstract
The objective of this study was to assess the cross-sectional areas (CSA) of lumbar paraspinal muscles and their fatty degeneration in adults with degenerative lumbar spondylolisthesis (DLS) diagnosed with chronic radiculopathy, compare them with those of the same age- and sex-related groups with [...] Read more.
The objective of this study was to assess the cross-sectional areas (CSA) of lumbar paraspinal muscles and their fatty degeneration in adults with degenerative lumbar spondylolisthesis (DLS) diagnosed with chronic radiculopathy, compare them with those of the same age- and sex-related groups with radiculopathy, and evaluate their correlations and the changes observed on magnetic resonance imaging (MRI). This retrospective study included 62 female patients aged 65–85 years, who were diagnosed with lumbar polyradiculopathy. The patients were divided into two groups: 30 patients with spondylolisthesis and 32 patients without spondylolisthesis. We calculated the CSA and fatty degeneration of the erector spinae (ES) and multifidus (MF) on axial T2-weighted magnetic resonance (MR) images from the inferior end plate of the L4 vertebral body levels. The functional CSA (FCSA): CSA ratio, skeletal muscle index (SMI), and MF CSA: ES CSA ratio were calculated and compared between the two groups using an independent t-test. We performed logistic regression analysis using spondylolisthesis as the dependent variable and SMI, FCSA, rFCSA, fat infiltration rate as independent variables. The result showed more fat infiltration of MF in patients with DLS (56.33 vs. 44.66%; p = 0.001). The mean FCSA (783.33 vs. 666.22 mm2; p = 0.028) of ES muscle was a statistically larger in the patients with DLS. The ES FCSA / total CSA was an independent predictor of lumbar spondylolisthesis (odd ratio =1.092, p = 0.016), while the MF FCSA / total CSA was an independent protective factor (odd ratio =0.898, p = 0.002) Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Phytoecdysteroids Do Not Have Anabolic Effects in Skeletal Muscle in Sedentary Aging Mice
Int. J. Environ. Res. Public Health 2021, 18(2), 370; https://doi.org/10.3390/ijerph18020370 - 06 Jan 2021
Cited by 3 | Viewed by 1258
Abstract
Skeletal muscle mass and strength are lost with aging. Phytoecdysteroids, in particular 20-hydroxyecdysone (20E), increase protein synthesis in C2C12 skeletal muscle cells and muscle strength in young rats. The objective of this study was to determine whether an extract from Ajuga turkestanica (ATE), [...] Read more.
Skeletal muscle mass and strength are lost with aging. Phytoecdysteroids, in particular 20-hydroxyecdysone (20E), increase protein synthesis in C2C12 skeletal muscle cells and muscle strength in young rats. The objective of this study was to determine whether an extract from Ajuga turkestanica (ATE), enriched in phytoecdysteroids, and 20E affect skeletal muscle mass and fiber size, fiber type, activation of the PI3K–Akt signaling pathway, and the mRNA levels of MAFbx, MuRF-1, and myostatin in sedentary aging mice. Aging male C57BL/6 mice (20 months old) received ATE, 20E, or vehicle (CT) once per day for 28 days or a single acute dose. Treatment did not alter body, muscle, or organ mass; fiber cross-sectional area; or fiber type in the triceps brachii or plantaris muscles. Likewise, protein synthesis signaling markers (i.e., phosphorylation of AktSer473 and p70S6kThr389) measured after either 28 days or acutely were unchanged. Neither ATE nor 20E treatment for 28 days affected the mRNA levels of MAFbx, MuRF-1, and myostatin. In conclusion, these data indicate that phytoecdysteroid treatment does not alter muscle mass or fiber type, nor does it activate protein synthesis signaling in the skeletal muscle of sedentary aging mice. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
The Effects of Exogenous Lactate Administration on the IGF1/Akt/mTOR Pathway in Rat Skeletal Muscle
Int. J. Environ. Res. Public Health 2020, 17(21), 7805; https://doi.org/10.3390/ijerph17217805 - 25 Oct 2020
Cited by 3 | Viewed by 917
Abstract
We investigated the effects of oral lactate administration on protein synthesis and degradation factors in rats over 2 h after intake. Seven-week-old male Sprague–Dawley rats were randomly divided into four groups (n = 8/group); their blood plasma levels of lactate, glucose, insulin, [...] Read more.
We investigated the effects of oral lactate administration on protein synthesis and degradation factors in rats over 2 h after intake. Seven-week-old male Sprague–Dawley rats were randomly divided into four groups (n = 8/group); their blood plasma levels of lactate, glucose, insulin, and insulin-like growth factor 1 (IGF1) were examined following sacrifice at 0, 30, 60, or 120 min after sodium lactate (2 g/kg) administration. We measured the mRNA expression levels of protein synthesis-related genes (IGF receptor, protein kinase B (Akt), mammalian target of rapamycin (mTOR)) or degradation-related genes (muscle RING-finger protein-1 (MuRF1), atrogin-1) and analyzed the protein expression and phosphorylation (activation) of Akt and mTOR. Post-administration, the plasma lactate concentration increased to 3.2 mmol/L after 60 min. Plasma glucose remained unchanged throughout, while insulin and IGF1 levels decreased after 30 min. The mRNA levels of IGF receptor and mTOR peaked after 60 min, and Akt expression was significantly upregulated from 30 to 120 min. However, MuRF1 and atrogin-1 expression levels were unaffected. Akt protein phosphorylation did not change significantly, whereas mTOR phosphorylation significantly increased after 30 min. Thus, lactate administration increased the mRNA and protein expression of protein-synthesis factors, suggesting that it can potentially promote skeletal muscle synthesis. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Article
Effects of Chemotherapy Treatment on Muscle Strength, Quality of Life, Fatigue, and Anxiety in Women with Breast Cancer
Int. J. Environ. Res. Public Health 2020, 17(19), 7289; https://doi.org/10.3390/ijerph17197289 - 06 Oct 2020
Cited by 4 | Viewed by 986
Abstract
The study aimed to evaluate the effects of chemotherapy treatment on muscle strength, quality of life, fatigue, and anxiety in women with breast cancer. Nineteen women who were undergoing a chemotherapy treatment (breast cancer treatment [BCT] group, 52.2 ± 13.1 years) and 18 [...] Read more.
The study aimed to evaluate the effects of chemotherapy treatment on muscle strength, quality of life, fatigue, and anxiety in women with breast cancer. Nineteen women who were undergoing a chemotherapy treatment (breast cancer treatment [BCT] group, 52.2 ± 13.1 years) and 18 women without cancer (control [CNT] group, 55.8 ± 8.4 years) answered questionnaires for evaluation of fatigue (Fatigue Scale), quality of life (Short-Form Healthy Survey [SF-36] questionnaire), and anxiety (State-Trait Anxiety Inventory [IDATE]) levels. Muscle strength was also assessed by an isometric grip test and an isokinetic knee extension test. Physical limitations, social and emotional domains of quality of life were lower in the BCT group in comparison to the CNT group (p = 0.002; p = 0.003; p = 0.0003, respectively). The other domains did not differ between groups (p > 0.05). There were no differences in fatigue and anxiety levels between both the BCT and CNT groups (p > 0.05). Additionally, isometric grip strength was higher in the CNT group when compared to the BCT group (p = 0.048). However, there were no differences between the BCT and CNT groups for peak torque and total work at both 60°.s−1 (p = 0.95 and p = 0.61, respectively) and 180°.s−1 (p = 0.94 and p = 0.72, respectively). These results suggest that three cycles of chemotherapy treatment may impair handgrip isometric strength and quality of life in women with breast cancer. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Review

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Review
Regulation of Energy Substrate Metabolism in Endurance Exercise
Int. J. Environ. Res. Public Health 2021, 18(9), 4963; https://doi.org/10.3390/ijerph18094963 - 07 May 2021
Viewed by 1828
Abstract
The human body requires energy to function. Adenosine triphosphate (ATP) is the cellular currency for energy-requiring processes including mechanical work (i.e., exercise). ATP used by the cells is ultimately derived from the catabolism of energy substrate molecules—carbohydrates, fat, and protein. In prolonged moderate [...] Read more.
The human body requires energy to function. Adenosine triphosphate (ATP) is the cellular currency for energy-requiring processes including mechanical work (i.e., exercise). ATP used by the cells is ultimately derived from the catabolism of energy substrate molecules—carbohydrates, fat, and protein. In prolonged moderate to high-intensity exercise, there is a delicate interplay between carbohydrate and fat metabolism, and this bioenergetic process is tightly regulated by numerous physiological, nutritional, and environmental factors such as exercise intensity and duration, body mass and feeding state. Carbohydrate metabolism is of critical importance during prolonged endurance-type exercise, reflecting the physiological need to regulate glucose homeostasis, assuring optimal glycogen storage, proper muscle fuelling, and delaying the onset of fatigue. Fat metabolism represents a sustainable source of energy to meet energy demands and preserve the ‘limited’ carbohydrate stores. Coordinated neural, hormonal and circulatory events occur during prolonged endurance-type exercise, facilitating the delivery of fatty acids from adipose tissue to the working muscle for oxidation. However, with increasing exercise intensity, fat oxidation declines and is unable to supply ATP at the rate of the exercise demand. Protein is considered a subsidiary source of energy supporting carbohydrates and fat metabolism, contributing to approximately 10% of total ATP turnover during prolonged endurance-type exercise. In this review we present an overview of substrate metabolism during prolonged endurance-type exercise and the regulatory mechanisms involved in ATP turnover to meet the energetic demands of exercise. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Review
Effect of Various Exercise Regimens on Selected Exercise-Induced Cytokines in Healthy People
Int. J. Environ. Res. Public Health 2021, 18(3), 1261; https://doi.org/10.3390/ijerph18031261 - 31 Jan 2021
Cited by 6 | Viewed by 2444
Abstract
Different forms of physical activity—endurance, resistance or dynamic power—stimulate cytokine release from various tissues to the bloodstream. Receptors for exercise-induced cytokines are present in muscle tissue, adipose tissue, liver, brain, bones, cardiovascular system, immune system, pancreas, and skin. They have autocrine, paracrine and [...] Read more.
Different forms of physical activity—endurance, resistance or dynamic power—stimulate cytokine release from various tissues to the bloodstream. Receptors for exercise-induced cytokines are present in muscle tissue, adipose tissue, liver, brain, bones, cardiovascular system, immune system, pancreas, and skin. They have autocrine, paracrine and endocrine activities. Many of them regulate the myocyte growth and differentiation necessary for muscle hypertrophy and myogenesis. They also modify energy homeostasis, lipid, carbohydrate, and protein metabolism, regulate inflammation and exchange information (crosstalk) between remote organs. So far, interleukin 6 and irisin have been the best studied exercise-induced cytokines. However, many more can be grouped into myokines, hepatokines and adipomyokines. This review focuses on the less known exercise-induced cytokines such as myostatin, follistatin, decorin, brain-derived neurotrophic factor, fibroblast growth factor 21 and interleukin 15, and their relation to various forms of exercise, i.e., acute vs. chronic, regular training in healthy people. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Review
PGC-1α-Targeted Therapeutic Approaches to Enhance Muscle Recovery in Aging
Int. J. Environ. Res. Public Health 2020, 17(22), 8650; https://doi.org/10.3390/ijerph17228650 - 21 Nov 2020
Cited by 5 | Viewed by 1248
Abstract
Impaired muscle recovery (size and strength) following a disuse period commonly occurs in older adults. Many of these individuals are not able to adequately exercise due to pain and logistic barriers. Thus, nutritional and pharmacological therapeutics, that are translatable, are needed to promote [...] Read more.
Impaired muscle recovery (size and strength) following a disuse period commonly occurs in older adults. Many of these individuals are not able to adequately exercise due to pain and logistic barriers. Thus, nutritional and pharmacological therapeutics, that are translatable, are needed to promote muscle recovery following disuse in older individuals. Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) may be a suitable therapeutic target due to pleiotropic regulation of skeletal muscle. This review focuses on nutritional and pharmacological interventions that target PGC-1α and related Sirtuin 1 (SIRT1) and 5′ AMP-activated protein kinase (AMPKα) signaling in muscle and thus may be rapidly translated to prevent muscle disuse atrophy and promote recovery. In this review, we present several therapeutics that target PGC-1α in skeletal muscle such as leucine, β-hydroxy-β-methylbuyrate (HMB), arginine, resveratrol, metformin and combination therapies that may have future application to conditions of disuse and recovery in humans. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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Review
A Systematic Review with Meta-Analysis of the Effect of Resistance Training on Whole-Body Muscle Growth in Healthy Adult Males
Int. J. Environ. Res. Public Health 2020, 17(4), 1285; https://doi.org/10.3390/ijerph17041285 - 17 Feb 2020
Cited by 9 | Viewed by 5704
Abstract
We performed a systematic review and meta-analysis to study all published clinical trial interventions, determined the magnitude of whole-body hypertrophy in humans (healthy males) and observed the individual responsibility of each variable in muscle growth after resistance training (RT). Searches were conducted in [...] Read more.
We performed a systematic review and meta-analysis to study all published clinical trial interventions, determined the magnitude of whole-body hypertrophy in humans (healthy males) and observed the individual responsibility of each variable in muscle growth after resistance training (RT). Searches were conducted in PubMed, Web of Science and the Cochrane Library from database inception until 10 May 2018 for original articles assessing the effects of RT on muscle size after interventions of more than 2 weeks of duration. Specifically, we obtain the variables fat-free mass (FMM), lean muscle mass (LMM) and skeletal muscle mass (SMM). The effects on outcomes were expressed as mean differences (MD) and a random-effects meta-analysis and meta-regressions determined covariates (age, weight, height, durations in weeks…) to explore the moderate effect related to the participants and characteristics of training. One hundred and eleven studies (158 groups, 1927 participants) reported on the effects of RT for muscle mass. RT significantly increased muscle mass (FFM+LMM+SMM; Δ1.53 kg; 95% CI [1.30, 1.76], p < 0.001; I2 = 0%, p = 1.00). Considering the overall effects of the meta-regression, and taking into account the participants’ characteristics, none of the studied covariates explained any effect on changes in muscle mass. Regarding the training characteristics, the only significant variable that explained the variance of the hypertrophy was the sets per workout, showing a significant negative interaction (MD; estimate: 1.85, 95% CI [1.45, 2.25], p < 0.001; moderator: -0.03 95% CI [−0.05, −0.001] p = 0.04). In conclusion, RT has a significant effect on the improvement of hypertrophy (~1.5 kg). The excessive sets per workout affects negatively the muscle mass gain. Full article
(This article belongs to the Special Issue Regulation of Muscle Mass, Exercise, Metabolism)
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