Muscle Mass and Protein Metabolism

2004 ◽  
pp. 111-124 ◽  
Author(s):  
Gianni Biolo ◽  
Marcello De De Cicco
Keyword(s):  
Muscle Mass ◽  
Protein Metabolism

MOLECULAR ASPECTS OF SARCOPENIA PATHOGENESIS IN CHRONOC KIDNEY DISEASE: INTEGRATED ROLE OF mTOR

2018 ◽  
Vol 22 (5) ◽  
pp. 9-16 ◽  
Author(s):  
M. Z. Gasanov
Keyword(s):  
Kidney Disease ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Mammalian Target Of Rapamycin ◽  
Healthy Person ◽  
Scientific Review ◽  
Cytoskeleton Organization ◽  
Molecular Aspects ◽  
End Stage

In recent decades, the main pathogenetic mechanisms for maintaining muscle mass and strength have been discovered. Most of the scientific papers on the molecular aspects of the  pathogenesis of sarcopenia were focused on the Akt-signaling  pathway. The subject of the study were people of elderly and senile  age, immobilized patients, patients with CKD 1-4 stages, animals. However, recently more attention has been paid to the role  of protein – the mammalian target of rapamycin mTOR. It seems to be a key link in the control of muscle mass and is a promising  marker in understanding the mechanisms of the pathogenesis of  sarcopenia. Its importance in protein metabolism in patients with  end stage kidney disease is not studied and requires further research. The presented scientific review contains  information on the role of mTOR and its components – mTORC1 and mTORC2 in maintaining muscle mass and strength in a healthy  person and in the formation of sarcopenia in patients with CKD. The  general aid of mTORC1 complex is regulation of protein production  which is necessary for cell growth and differentiation. mTORC2  complex functions are not enough studied. It is established that it  plays important role in such biological processes as cytoskeleton  organization, intracellular homeostasis maintaining, so it provides  cell resistance and cell survivability in negative external and internal  impulses. mTOR protein can be considered as promising molecular  marker in diagnostics of protein metabolism early disturbances in  patients with CKD and also as additory factor of sarcopenia severity assessment.

No difference in insulin sensitivity between healthy postmenopausal women with or without sarcopenia: a pilot study

2007 ◽  
Vol 32 (3) ◽  
pp. 426-433 ◽  
Author(s):  
Eric D.B. Goulet ◽  
Christine Lord ◽  
Jean-Philippe Chaput ◽  
Mylène Aubertin-Leheudre ◽  
Martin Brochu ◽  
...  
Keyword(s):  
Insulin Sensitivity ◽  
Total Energy ◽  
Postmenopausal Women ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Fat Free Mass ◽  
Older Individuals ◽  
Food Record ◽  
Muscle Protein Metabolism

Insulin plays a pivotal role in skeletal muscle protein metabolism and its action decreases with age. A loss of muscle mass, termed sarcopenia, also occurs with age. The age-associated decline in insulin sensitivity (IS) may negatively alter muscle protein metabolism and, therefore, be implicated in the aetiology of sarcopenia. However, no studies have yet compared the level of IS between older individuals with or without sarcopenia. Thus, in this study, we compared the IS of 20 class I sarcopenics (CIS), 8 class II sarcopeniscs (CIIS), and 16 non-sarcopenics (NS), among a group of otherwise healthy, non-obese, postmenopausal women. IS was estimated with the quantitative IS check index (QUICKI). Muscle mass index (MMI), which was used to determine sarcopenia, was calculated as follows: (appendicular  muscle  mass × 1.19) – 1.01/h2, where h = height. Fat-free mass (FFM), fat mass (FM), and trunk FM (TFM) were measured by dual-energy X-ray absorptiometry. Accelerometry and indirect calorimetry were used to estimate resting (REE), daily (DEE), and physical activity (PAEE) energy expenditure. A 3 d food record was used to determine total energy, protein (animal and vegetal), and carbohydrate intakes. As expected, MMI and FFM differed significantly among groups. However, no significant differences were found among groups for IS, FM, TFM, REE, DEE, PAEE, or total energy, protein (both animal and vegetable), and carbohydrate intakes. Using QUICKI, a surrogate measure of IS, the present results suggest that the action of insulin does not play an important role in the development and maintenance of sarcopenia in healthy, non-obese, postmenopausal women.

scholarly journals Phenotypic regulation of animal skeletal muscle protein metabolism

2019 ◽  
Vol 9 (4) ◽  
pp. 651-656 ◽  
Author(s):  
K. T. Erimbetov ◽  
O. V. Obvintseva ◽  
A. V. Fedorova ◽  
R. A. Zemlyanoy ◽  
A. G. Solovieva
Keyword(s):  
Skeletal Muscle ◽  
Protein Synthesis ◽  
Signaling Pathways ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mrna Translation ◽  
Mtorc1 Signaling ◽  
Muscle Protein Metabolism

This review highlights the current state of phenotypic mechanisms of regulation of muscle protein metabolism in animals. Since the skeletal muscle represents 40–50% of body mass in mammals it is a critical regulator of overall metabolism. Therefore, an understanding of the processes involved in the postnatal increase in muscle mass, with associated accumulation of protein, is fundamental. Throughout life, a delicate balance exists between protein synthesis and degradation that is essential for growth and normal health of humans and animals. Signaling pathways coordinate muscle protein balance. Anabolic and catabolic stimuli are integrated through the PKB/Akt-mTORC1 signaling to regulate mechanisms that control muscle protein synthesis and breakdown. At an early periods of intensive growth, muscle mass is stimulated by an increase in protein synthesis at the level of mRNA translation. Throughout the life, proteolytic processes including autophagy lysosomal system, ubiquitin proteasome pathway, calcium-dependent calpains and cysteine protease caspase enzyme cascade influence the growth of muscle mass. Several signal transmission networks direct and coordinate these processes along with quality control mechanisms to maintain protein homeostasis (proteostasis). Genetic factors, hormones, amino acids, phytoecdysteroids, and rhodanines affect the protein metabolism via signaling pathways, changing the ability and / or efficiency of muscle growth.

scholarly journals “Nutraceuticals” in relation to human skeletal muscle and exercise

2017 ◽  
Vol 312 (4) ◽  
pp. E282-E299 ◽  
Author(s):  
Colleen S. Deane ◽  
Daniel J. Wilkinson ◽  
Bethan E. Phillips ◽  
Kenneth Smith ◽  
Timothy Etheridge ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Exercise Performance ◽  
Protein Metabolism ◽  
Mass Function ◽  
Oxidative Capacity ◽  
Whole Body ◽  
Endurance Capacity ◽  
Nutraceutical Compounds ◽  
Whole Body Metabolism

Skeletal muscles have a fundamental role in locomotion and whole body metabolism, with muscle mass and quality being linked to improved health and even lifespan. Optimizing nutrition in combination with exercise is considered an established, effective ergogenic practice for athletic performance. Importantly, exercise and nutritional approaches also remain arguably the most effective countermeasure for muscle dysfunction associated with aging and numerous clinical conditions, e.g., cancer cachexia, COPD, and organ failure, via engendering favorable adaptations such as increased muscle mass and oxidative capacity. Therefore, it is important to consider the effects of established and novel effectors of muscle mass, function, and metabolism in relation to nutrition and exercise. To address this gap, in this review, we detail existing evidence surrounding the efficacy of a nonexhaustive list of macronutrient, micronutrient, and “nutraceutical” compounds alone and in combination with exercise in relation to skeletal muscle mass, metabolism (protein and fuel), and exercise performance (i.e., strength and endurance capacity). It has long been established that macronutrients have specific roles and impact upon protein metabolism and exercise performance, (i.e., protein positively influences muscle mass and protein metabolism), whereas carbohydrate and fat intakes can influence fuel metabolism and exercise performance. Regarding novel nutraceuticals, we show that the following ones in particular may have effects in relation to 1) muscle mass/protein metabolism: leucine, hydroxyl β-methylbutyrate, creatine, vitamin-D, ursolic acid, and phosphatidic acid; and 2) exercise performance: (i.e., strength or endurance capacity): hydroxyl β-methylbutyrate, carnitine, creatine, nitrates, and β-alanine.

Effect of prednisone on protein metabolism in Duchenne dystrophy

1995 ◽  
Vol 268 (1) ◽  
pp. E67-E74 ◽  
Author(s):  
Z. Rifai ◽  
S. Welle ◽  
R. T. Moxley ◽  
M. Lorenson ◽  
R. C. Griggs
Keyword(s):  
Protein Synthesis ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Whole Body ◽  
Duchenne Dystrophy ◽  
Body Protein ◽  
Creatinine Excretion ◽  
Muscle Testing

Prednisone improves strength in Duchenne dystrophy and changes the natural history of the disease. We studied the in vivo effects of prednisone (0.75 mg.kg-1.day-1) on muscle and whole body protein metabolism in six patients with Duchenne dystrophy and three patients with Becker dystrophy. Patients were admitted to the Clinical Research Center for study and consumed a constant flesh-free diet. Strength was measured by manual and quantitative muscle testing. Fractional muscle protein breakdown was estimated by the ratio of 3-methylhistidine to creatinine excretion determined in three consecutive 24-h urine collections. Whole body protein kinetics were studied in the postabsorptive state using a primed continuous infusion of L-[1-13C]leucine. Fractional muscle protein synthesis was determined from tracer incorporation into noncollagen muscle protein obtained by needle biopsy. After 6-8 wk of prednisone treatment, average muscle strength increased by 15% (P < 0.04), and 24-h creatinine excretion (an index of muscle mass) increased by 21% (P = 0.002). 3-Methylhistidine excretion decreased by 10%, but the change was not statistically significant. The ratio of 3-methylhistidine to creatinine excretion decreased by 26% (P < 0.04). Fractional muscle protein synthesis and whole body protein synthesis and breakdown did not change significantly. We conclude that the beneficial effect of prednisone on strength in Duchenne dystrophy appears to be associated with an increase in muscle mass, which may be mediated by inhibition of muscle proteolysis rather than stimulation of muscle protein synthesis.

scholarly journals Down-Regulation of Akt/Mammalian Target of Rapamycin Signaling Pathway in Response to Myostatin Overexpression in Skeletal Muscle

Endocrinology ◽  
2008 ◽  
Vol 150 (1) ◽  
pp. 286-294 ◽  
Author(s):  
Adel Amirouche ◽  
Anne-Cécile Durieux ◽  
Sébastien Banzet ◽  
Nathalie Koulmann ◽  
Régis Bonnefoy ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Signaling Pathway ◽  
Muscle Mass ◽  
Protein Metabolism ◽  
Skeletal Muscle Mass ◽  
Mammalian Target Of Rapamycin ◽  
Mtor Signaling ◽  
Target Of Rapamycin ◽  
Gene Electrotransfer ◽  
Mtor Signaling Pathway

Myostatin, a member of the TGF-β family, has been identified as a master regulator of embryonic myogenesis and early postnatal skeletal muscle growth. However, cumulative evidence also suggests that alterations in skeletal muscle mass are associated with dysregulation in myostatin expression and that myostatin may contribute to muscle mass loss in adulthood. Two major branches of the Akt pathway are relevant for the regulation of skeletal muscle mass, the Akt/mammalian target of rapamycin (mTOR) pathway, which controls protein synthesis, and the Akt/forkhead box O (FOXO) pathway, which controls protein degradation. Here, we provide further insights into the mechanisms by which myostatin regulates skeletal muscle mass by showing that myostatin negatively regulates Akt/mTOR signaling pathway. Electrotransfer of a myostatin expression vector into the tibialis anterior muscle of Sprague Dawley male rats increased myostatin protein level and decreased skeletal muscle mass 7 d after gene electrotransfer. Using RT-PCR and immunoblot analyses, we showed that myostatin overexpression was ineffective to alter the ubiquitin-proteasome pathway. By contrast, myostatin acted as a negative regulator of Akt/mTOR pathway. This was supported by data showing that the phosphorylation of Akt on Thr308, tuberous sclerosis complex 2 on Thr1462, ribosomal protein S6 on Ser235/236, and 4E-BP1 on Thr37/46 was attenuated 7 d after myostatin gene electrotransfer. The data support the conclusion that Akt/mTOR signaling is a key target that accounts for myostatin function during muscle atrophy, uncovering a novel role for myostatin in protein metabolism and more specifically in the regulation of translation in skeletal muscle. Myostatin down-regulates Akt/mammalian target of rapamycin (mTOR) signaling pathway uncovering a novel role for myostatin in protein metabolism and more specifically in the regulation of translation in skeletal muscle.

scholarly journals Long-Term Habitual Exercise and Combination of β-hydroxy-β-methylbutyrate Plus Black Ginger Maintain Muscle Health in SAMP8 Mice

2020 ◽  
Author(s):  
Kai Aoki ◽  
Masaki Konno ◽  
Katsuyuki Tokinoya ◽  
Katsunari Honda ◽  
Takuya Abe ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Muscle Mass ◽  
Mitochondrial Function ◽  
Protein Metabolism ◽  
Muscle Protein ◽  
Muscle Aging ◽  
Habitual Exercise ◽  
Muscle Protein Metabolism ◽  
Muscle Health ◽  
Samp8 Mice

Muscle mass and strength decrease with aging, but habitual exercise can maintain muscle health. &beta;-Hydroxy-&beta;-methyl butyrate calcium (HMB) and black ginger (BG) are anti-oxidants that have been reported to improve muscle protein metabolism and energy production; these molecules may have synergistic effects. The senescence-accelerated mouse-prone 8 (SAMP8) model is a useful model of muscle aging. Therefore, in this study, we explored how the combination of habitual exercise, HMB, and BG affected muscle aging. We used 28-week-old SAMP8 mice divided into five groups: control, exercise (Ex), Ex+BG, Ex+HMB, and Ex+BG+HMB (Ex+Comb). Mice were required to run on a treadmill for 16 weeks at 5 days per week. In 44-week-old mice, grip strength tests and dissection were conducted. Muscle weight was measured, and the gastrocnemius muscle was subjected to quantitative polymerase chain reaction and immunoblotting. Muscle mass and strength were preserved in the Ex+Comb group, and mitochondrial function was preserved through suppressing oxidative stress. Muscle protein synthesis signaling was improved in the Ex+Comb group. Autophagy and the ubiquitin system were normalized by Ex+Comb treatment. Overall, habitual exercise and HMB plus BG treatment maintained muscle health by suppressing oxidative stress, preserving mitochondrial function, and maintaining muscle protein metabolism in SAMP8 mice.

Supplementation with beta-hydroxy-beta-methylbutyrate impacts glucose homeostasis and increases liver size in trained mice

2020 ◽  
Vol 90 (1-2) ◽  
pp. 113-123
Author(s):  
Ines Schadock ◽  
Barbara G. Freitas ◽  
Irae L. Moreira ◽  
Joao A. Rincon ◽  
Marcio Nunes Correa ◽  
...  
Keyword(s):  
Strength Training ◽  
Muscle Mass ◽  
Glucose Homeostasis ◽  
Fasting Blood Glucose ◽  
Hepatic Metabolism ◽  
Mass Gain ◽  
Trained Group ◽  
Tissue Mass ◽  
Liver Size ◽  
Intensive Training

Abstract. β-hydroxy-β-methyl butyrate (HMB) is a bioactive metabolite derived from the amino acid leucine, usually applied for muscle mass increase during physical training, as well as for muscle mass maintenance in debilitating chronic diseases. The hypothesis of the present study is that HMB is a safe supplement for muscle mass gain by strength training. Based on this, the objective was to measure changes in body composition, glucose homeostasis and hepatic metabolism of HMB supplemented mice during strength training. Two of four groups of male mice (n = 6/group) underwent an 8-week training period session (climbing stairs) with or without HMB supplementation (190 mg/kgBW per day). We observed lower body mass gain (4.9 ± 0.43% versus 1.2 ± 0.43, p < 0.001) and increased liver mass (40.9 ± 0.9 mg/gBW versus 44.8 ± 1.3, p < 0.001) in the supplemented trained group compared with the non-supplemented groups. The supplemented trained group had an increase in relative adipose tissue mass (12.4 ± 0.63 mg/gBW versus 16.1 ± 0.88, P < 0.01) compared to the non-supplemented untrained group, and an increase in fasting blood glucose (111 ± 4.58 mg/dL versus 122 ± 3.70, P < 0.05) and insulin resistance (3.79 ± 0.19 % glucose decay/min versus 2.45 ± 0.28, P < 0.05) comparing with non-supplemented trained group. Adaptive heart hypertrophy was observed only in the non-supplemented trained group (4.82 ± 0.05 mg/gBW versus 5.12 ± 0.13, P < 0.05). There was a higher hepatic insulin-like growth factor-1 expression (P = 0.002) in supplemented untrained comparing with non-supplemented untrained group. Gene expression of gluconeogenesis regulatory factors was increased by training and reduced by HMB supplementation. These results confirm that HMB supplementation associated with intensive training protocol drives changes in glucose homeostasis and liver metabolism in mice.

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