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Pradhan R, Dieterich W, Natarajan A, Schwappacher R, Reljic D, Herrmann HJ, Neurath MF, Zopf Y. Influence of Amino Acids and Exercise on Muscle Protein Turnover, Particularly in Cancer Cachexia. Cancers (Basel) 2024; 16:1921. [PMID: 38791998 PMCID: PMC11119313 DOI: 10.3390/cancers16101921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/15/2024] [Accepted: 05/16/2024] [Indexed: 05/26/2024] Open
Abstract
Cancer cachexia is a multifaceted syndrome that impacts individuals with advanced cancer. It causes numerous pathological changes in cancer patients, such as inflammation and metabolic dysfunction, which further diminish their quality of life. Unfortunately, cancer cachexia also increases the risk of mortality in affected individuals, making it an important area of focus for cancer research and treatment. Several potential nutritional therapies are being tested in preclinical and clinical models for their efficacy in improving muscle metabolism in cancer patients. Despite promising results, no special nutritional therapies have yet been validated in clinical practice. Multiple studies provide evidence of the benefits of increasing muscle protein synthesis through an increased intake of amino acids or protein. There is also increasing evidence that exercise can reduce muscle atrophy by modulating protein synthesis. Therefore, the combination of protein intake and exercise may be more effective in improving cancer cachexia. This review provides an overview of the preclinical and clinical approaches for the use of amino acids with and without exercise therapy to improve muscle metabolism in cachexia.
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Affiliation(s)
- Rashmita Pradhan
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Walburga Dieterich
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Anirudh Natarajan
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Raphaela Schwappacher
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Dejan Reljic
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Hans J. Herrmann
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
| | - Markus F. Neurath
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
| | - Yurdagül Zopf
- Department of Medicine, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany; (R.P.); (W.D.); (A.N.); (R.S.); (D.R.); (H.J.H.); (M.F.N.)
- Hector-Center for Nutrition, Exercise and Sports, Department of Medicine 1, Friedrich-Alexander University Erlangen-Nürnberg, 91054 Erlangen, Germany
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Kim Y, Park S, Lee J, Jang J, Jung J, Koh JH, Choi CS, Wolfe RR, Kim IY. Essential Amino Acid-Enriched Diet Alleviates Dexamethasone-Induced Loss of Muscle Mass and Function through Stimulation of Myofibrillar Protein Synthesis and Improves Glucose Metabolism in Mice. Metabolites 2022; 12:metabo12010084. [PMID: 35050206 PMCID: PMC8778336 DOI: 10.3390/metabo12010084] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/14/2022] [Accepted: 01/14/2022] [Indexed: 01/18/2023] Open
Abstract
Dexamethasone (DEX) induces dysregulation of protein turnover, leading to muscle atrophy and impairment of glucose metabolism. Positive protein balance, i.e., rate of protein synthesis exceeding rate of protein degradation, can be induced by dietary essential amino acids (EAAs). In this study, we investigated the roles of an EAA-enriched diet in the regulation of muscle proteostasis and its impact on glucose metabolism in the DEX-induced muscle atrophy model. Mice were fed normal chow or EAA-enriched chow and were given daily injections of DEX over 10 days. We determined muscle mass and functions using treadmill running and ladder climbing exercises, protein kinetics using the D2O labeling method, molecular signaling using immunoblot analysis, and glucose metabolism using a U-13C6 glucose tracer during oral glucose tolerance test (OGTT). The EAA-enriched diet increased muscle mass, strength, and myofibrillar protein synthesis rate, concurrent with improved glucose metabolism (i.e., reduced plasma insulin concentrations and increased insulin sensitivity) during the OGTT. The U-13C6 glucose tracing revealed that the EAA-enriched diet increased glucose uptake and subsequent glycolytic flux. In sum, our results demonstrate a vital role for the EAA-enriched diet in alleviating the DEX-induced muscle atrophy through stimulation of myofibrillar proteins synthesis, which was associated with improved glucose metabolism.
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Affiliation(s)
- Yeongmin Kim
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea; (Y.K.); (J.L.); (J.J.)
| | - Sanghee Park
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon 21999, Korea; (S.P.); (J.-H.K.); (C.S.C.)
| | - Jinseok Lee
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea; (Y.K.); (J.L.); (J.J.)
| | - Jiwoong Jang
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 21999, Korea;
- Gil Medical Center, Department of Internal Medicine, Gachon University, Incheon 21565, Korea
| | - Jiyeon Jung
- Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon 21999, Korea; (Y.K.); (J.L.); (J.J.)
| | - Jin-Ho Koh
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon 21999, Korea; (S.P.); (J.-H.K.); (C.S.C.)
| | - Cheol Soo Choi
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon 21999, Korea; (S.P.); (J.-H.K.); (C.S.C.)
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 21999, Korea;
- Gil Medical Center, Department of Internal Medicine, Gachon University, Incheon 21565, Korea
| | - Robert R. Wolfe
- The Center for Translational Research in Aging and Longevity, Department of Geriatrics, Donald W. Reynolds Institute on Aging, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA;
| | - Il-Young Kim
- Department of Molecular Medicine, College of Medicine, Gachon University, Incheon 21999, Korea; (S.P.); (J.-H.K.); (C.S.C.)
- Korea Mouse Metabolic Phenotyping Center, Lee Gil Ya Cancer and Diabetes Institute, Gachon University, Incheon 21999, Korea;
- Correspondence: ; Tel.: +82-32-899-6685
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Weber MG, Dias SS, de Angelis TR, Fernandes EV, Bernardes AG, Milanez VF, Jussiani EI, de Paula Ramos S. The use of BCAA to decrease delayed-onset muscle soreness after a single bout of exercise: a systematic review and meta-analysis. Amino Acids 2021; 53:1663-1678. [PMID: 34669012 DOI: 10.1007/s00726-021-03089-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 10/07/2021] [Indexed: 10/20/2022]
Abstract
Branched-chain amino acids (BCAA) are used as a recovery method after exercise-induced muscle damage (EIMD). Although data suggest that BCAA may alleviate the delayed-onset muscle soreness (DOMS) evoked by EIMD, there is no consensus about the most effective supplementation protocol. To investigate the effects of BCAA on DOMS after a single exercise session that caused EIMD, a systematic review and meta-analysis were conducted on the effectiveness of BCAA supplementation to reduce DOMS symptoms in healthy subjects after a single session of EIMD. Randomized clinical trials (RCT) were searched in Medline, Cochrane Library, Science Direct, SciELO, LILACS, SciVerse Scopus, Springer Link journals, Wiley Online Library, and Scholar Google, until May 2021. Ten RCTs were included in the systematic review and nine in the meta-analysis. Seven studies demonstrated that BCAA reduced DOMS after 24 to 72 h. BCAA doses of up to 255 mg/kg/day, or in trained subjects, for mild to moderate EIMD, could blunt DOMS symptoms. However, high variability between studies due to training status, different doses, time of treatment, and severity of EIMD do not allow us to conclude whether BCAA supplementation is efficient in untrained subjects, applied acutely or during a period of pre to post days of EIMD, and at higher doses (> 255 mg/kg/day). The overall effects of BCAA on DOMS after a single session of exercise were considered useful for improving muscle recovery by reducing DOMS in trained subjects, at low doses, in mild to moderate EIMD, and should not be administered only after the EIMD protocol.
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Affiliation(s)
- Martim Gomes Weber
- Research Group in Tissue Regeneration, Adaptation and Repair, State University of Londrina, Londrina, Brazil
| | - Silas Seolin Dias
- Research Group in Tissue Regeneration, Adaptation and Repair, State University of Londrina, Londrina, Brazil
| | - Tarlyson Regioli de Angelis
- Research Group in Tissue Regeneration, Adaptation and Repair, State University of Londrina, Londrina, Brazil
| | - Eduardo Vignoto Fernandes
- Research Group in Tissue Regeneration, Adaptation and Repair, Federal University of Jataí, Jataí, Brazil
| | - Andrea Gomes Bernardes
- Research Group in Tissue Regeneration, Adaptation and Repair, State University of Londrina, Londrina, Brazil
| | | | | | - Solange de Paula Ramos
- Research Group in Tissue Regeneration, Adaptation and Repair, Center of Biological Sciences, State University of Londrina, Rodovia Celso Garcia Cid PR 445 km380, Londrina, Paraná, CEP: 89067-900, Brazil.
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Doma K, Singh U, Boullosa D, Connor JD. The effect of branched-chain amino acid on muscle damage markers and performance following strenuous exercise: a systematic review and meta-analysis. Appl Physiol Nutr Metab 2021; 46:1303-1313. [PMID: 34612716 DOI: 10.1139/apnm-2021-0110] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
This systematic review and meta-analysis determined whether the ergogenic effects of branched-chain amino acids (BCAA) ameliorated markers of muscle damage and performance following strenuous exercise. In total, 25 studies were included, consisting of 479 participants (age 24.3 ± 8.3 years, height 1.73 ± 0.06 m, body mass 70.8 ± 9.5 kg, females 26.3%). These studies were rated as fair to excellent following the PEDro scale. The outcome measures were compared between the BCAA and placebo conditions at 24 and 48 hours following muscle-damaging exercises, using standardised mean differences and associated p-values via forest plots. Our meta-analysis demonstrated significantly lower levels of indirect muscle damage markers (creatine kinase, lactate dehydrogenase and myoglobin) at 48 hours post-exercise (standardised mean difference [SMD] = -0.41; p < 0.05) for the BCAA than placebo conditions, whilst muscle soreness was significant at 24 hours post-exercise (SMD = -0.28 ≤ d ≤ -0.61; p < 0.05) and 48 hours post-exercise (SMD = -0.41 ≤ d≤ -0.92; p < 0.01). However, no significant differences were identified between the BCAA and placebo conditions for muscle performance at 24 or 48 hours post-exercise (SMD = 0.08 ≤ d ≤ 0.21; p > 0.05). Overall, BCAA reduced the level of muscle damage biomarkers and muscle soreness following muscle-damaging exercises. However, the potential benefits of BCAA for muscle performance recovery is questionable and warrants further investigation to determine the practicality of BCAA for ameliorating muscle damage symptoms in diverse populations. PROSPERO registration number: CRD42020191248. Novelty: BCAA reduces the level of creatine kinase and muscle soreness following strenuous exercise with a dose-response relationship. BCAA does not accelerate recovery for muscle performance.
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Affiliation(s)
- Kenji Doma
- College of Healthcare Sciences, Sports and Exercise Science, James Cook University, Douglas, Queensland, Australia
| | - Utkarsh Singh
- Sports Dynamix Private Limited, Chennai, Nadu, India
| | - Daniel Boullosa
- College of Healthcare Sciences, Sports and Exercise Science, James Cook University, Douglas, Queensland, Australia.,INISA, Federal University of Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil
| | - Jonathan Douglas Connor
- College of Healthcare Sciences, Sports and Exercise Science, James Cook University, Douglas, Queensland, Australia
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Arroyo-Cerezo A, Cerrillo I, Ortega Á, Fernández-Pachón MS. Intake of branched chain amino acids favors post-exercise muscle recovery and may improve muscle function: optimal dosage regimens and consumption conditions. J Sports Med Phys Fitness 2021; 61:1478-1489. [PMID: 33586928 DOI: 10.23736/s0022-4707.21.11843-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Numerous sportspeople consume nutritional ergogenic aids, including branched chain amino acids (BCAA), considered to favor post-exercise muscle recovery. The purpose of this study was to assess the effect of BCAA on recovery from muscle damage produced by high-intensity exercise and muscle function. This allowed to define the optimal dosage regimen and consumption conditions taking into account the combination of BCAA with other products. EVIDENCE ACQUISITION A systematic review of the scientific literature published over the past 15 years using the PubMed/MEDLINE, Scopus and Web of Science databases was carried out. Nineteen articles were selected. EVIDENCE SYNTHESIS The most optimal regimen for post-exercise muscle recovery and/or muscle function after high-intensity resistance exercise was 2-10 g BCAA/day (leucine: isoleucine: valine at 2:1:1), consumed as a supplement alone or combined with arginine and carbohydrates, 3 previous days before exercise, immediately before and after exercise, regardless of training level. This treatment can improve perceived muscle damage, fatigue, circumference of arm/leg, counter movement jump, maximum muscle strength and maximum voluntary contraction, and reduce creatine kinase and lactate dehydrogenase levels, mainly in young males. CONCLUSIONS Intake of BCAA favors post-exercise muscle recovery and may improve muscle function. The present review can serve as a guidance for high intensity endurance athletes who need to reduce post-exercise muscle damage and maintain or improve muscle function, especially in training periods and competition events planned with short rest periods.
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Affiliation(s)
- Alejandra Arroyo-Cerezo
- Area of Nutrition and Food Sciences, Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - Isabel Cerrillo
- Area of Nutrition and Food Sciences, Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain
| | - Ángeles Ortega
- Area of Nutrition and Food Sciences, Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain.,Biomedical Research Networking Center in Diabetes and Associated Metabolic Disorders (CIBERDEM), Madrid, Spain
| | - María-Soledad Fernández-Pachón
- Area of Nutrition and Food Sciences, Department of Molecular Biology and Biochemical Engineering, Universidad Pablo de Olavide, Seville, Spain -
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Ruocco C, Segala A, Valerio A, Nisoli E. Essential amino acid formulations to prevent mitochondrial dysfunction and oxidative stress. Curr Opin Clin Nutr Metab Care 2021; 24:88-95. [PMID: 33060458 DOI: 10.1097/mco.0000000000000704] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE OF REVIEW Both restriction and supplementation of specific amino acids or branched-chain amino acids (BCAAs) are described to improve metabolic homeostasis, energy balance, and health span. This review will discuss the recent findings of the role of amino acid supplements in the regulation of mitochondrial health. RECENT FINDINGS A mixture of essential amino acids (EAAs), BCAA enriched mixture, was found to extend healthy life span in elderly mice and prevent multiple diseases associated with an energy deficit, similarly to caloric restriction or fasting-mimicking diets. A growing body of evidence highlights mitochondria as the central target of this supplement: it promotes mitochondrial biogenesis and the activation of antioxidant defence systems in different physiological (e.g., exercise or ageing) or pathological conditions (e.g., sarcopenia, muscular dystrophy, liver steatosis, or impaired cognition). Based on these results, new formulas have been created enriched with Krebs cycle substrates, behaving more efficiently than BCAA enriched mixture. SUMMARY EAA-BCAA balanced supplements might be valuable not only for healthy individuals undergoing to energy deficit (e.g., athletes) during strenuous exercise or training but also against diseases characterized by a dysregulated catabolic state or mitochondrial dysfunction, such as age-related disorders. The associated mechanistic processes should be identified as potential pharmacological targets.
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Affiliation(s)
- Chiara Ruocco
- Department of Biomedical Technology and Translational Medicine, Center for Study and Research on Obesity, University of Milan, Milan
| | - Agnese Segala
- Department of Molecular and Translational Medicine, Brescia University, Brescia, Italy
| | - Alessandra Valerio
- Department of Molecular and Translational Medicine, Brescia University, Brescia, Italy
| | - Enzo Nisoli
- Department of Biomedical Technology and Translational Medicine, Center for Study and Research on Obesity, University of Milan, Milan
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Bongiovanni T, Genovesi F, Nemmer M, Carling C, Alberti G, Howatson G. Nutritional interventions for reducing the signs and symptoms of exercise-induced muscle damage and accelerate recovery in athletes: current knowledge, practical application and future perspectives. Eur J Appl Physiol 2020; 120:1965-1996. [PMID: 32661771 DOI: 10.1007/s00421-020-04432-3] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 07/04/2020] [Indexed: 12/12/2022]
Abstract
PURPOSE This review provides an overview of the current knowledge of the nutritional strategies to treat the signs and symptoms related to EIMD. These strategies have been organized into the following sections based upon the quality and quantity of the scientific support available: (1) interventions with a good level of evidence; (2) interventions with some evidence and require more research; and (3) potential nutritional interventions with little to-no-evidence to support efficacy. METHOD Pubmed, EMBASE, Scopus and Web of Science were used. The search terms 'EIMD' and 'exercise-induced muscle damage' were individually concatenated with 'supplementation', 'athletes', 'recovery', 'adaptation', 'nutritional strategies', hormesis'. RESULT Supplementation with tart cherries, beetroot, pomegranate, creatine monohydrate and vitamin D appear to provide a prophylactic effect in reducing EIMD. β-hydroxy β-methylbutyrate, and the ingestion of protein, BCAA and milk could represent promising strategies to manage EIMD. Other nutritional interventions were identified but offered limited effect in the treatment of EIMD; however, inconsistencies in the dose and frequency of interventions might account for the lack of consensus regarding their efficacy. CONCLUSION There are clearly varying levels of evidence and practitioners should be mindful to refer to this evidence-base when prescribing to clients and athletes. One concern is the potential for these interventions to interfere with the exercise-recovery-adaptation continuum. Whilst there is no evidence that these interventions will blunt adaptation, it seems pragmatic to use a periodised approach to administering these strategies until data are in place to provide and evidence base on any interference effect on adaptation.
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Affiliation(s)
- Tindaro Bongiovanni
- Department of Health, Performance and Recovery, Parma Calcio 1913, Parma, Italy.
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Milano, Italy.
| | | | - Monika Nemmer
- Nutrition Department Liverpool Football Club, Liverpool, UK
| | - Christopher Carling
- Centre for Elite Performance, French Football Federation, 75015, Paris, France
| | - Giampietro Alberti
- Department of Biomedical Sciences for Health, Università Degli Studi Di Milano, Milano, Italy
| | - Glyn Howatson
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, UK
- Water Research Group, North West University, Potchefstroom, South Africa
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Regulation of Skeletal Muscle Function by Amino Acids. Nutrients 2020; 12:nu12010261. [PMID: 31963899 PMCID: PMC7019684 DOI: 10.3390/nu12010261] [Citation(s) in RCA: 99] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 01/09/2020] [Accepted: 01/16/2020] [Indexed: 12/30/2022] Open
Abstract
Amino acids are components of proteins that also exist free-form in the body; their functions can be divided into (1) nutritional, (2) sensory, and (3) biological regulatory roles. The skeletal muscle, which is the largest organ in the human body, representing ~40% of the total body weight, plays important roles in exercise, energy expenditure, and glucose/amino acid usage—processes that are modulated by various amino acids and their metabolites. In this review, we address the metabolism and function of amino acids in the skeletal muscle. The expression of PGC1α, a transcriptional coactivator, is increased in the skeletal muscle during exercise. PGC1α activates branched-chain amino acid (BCAA) metabolism and is used for energy in the tricarboxylic acid (TCA) cycle. Leucine, a BCAA, and its metabolite, β-hydroxy-β-methylbutyrate (HMB), both activate mammalian target of rapamycin complex 1 (mTORC1) and increase protein synthesis, but the mechanisms of activation appear to be different. The metabolite of valine (another BCAA), β-aminoisobutyric acid (BAIBA), is increased by exercise, is secreted by the skeletal muscle, and acts on other tissues, such as white adipose tissue, to increase energy expenditure. In addition, several amino acid-related molecules reportedly activate skeletal muscle function. Oral 5-aminolevulinic acid (ALA) supplementation can protect against mild hyperglycemia and help prevent type 2 diabetes. β-alanine levels are decreased in the skeletal muscles of aged mice. β-alanine supplementation increased the physical performance and improved the executive function induced by endurance exercise in middle-aged individuals. Further studies focusing on the effects of amino acids and their metabolites on skeletal muscle function will provide data essential for the production of food supplements for older adults, athletes, and individuals with metabolic diseases.
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