scholarly journals Regulation of Skeletal Muscle Function by Amino Acids

Nutrients ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 261 ◽  
Author(s):  
Yasutomi Kamei ◽  
Yukino Hatazawa ◽  
Ran Uchitomi ◽  
Ryoji Yoshimura ◽  
Shinji Miura
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Amino Acid ◽  
Energy Expenditure ◽  
Muscle Function ◽  
Metabolic Diseases ◽  
Aminolevulinic Acid ◽  
The Body ◽  
Free Form ◽  
Skeletal Muscle Function

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.

scholarly journals Evaluation of Skeletal Muscle Function and Effects of Early Rehabilitation during Acute Heart Failure: Rationale and Study Design

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kinga Węgrzynowska-Teodorczyk ◽  
Agnieszka Siennicka ◽  
Krystian Josiak ◽  
Robert Zymliński ◽  
Monika Kasztura ◽  
...  
Keyword(s):  
Heart Failure ◽  
Skeletal Muscle ◽  
Acute Heart Failure ◽  
Muscle Tissue ◽  
Muscle Function ◽  
Skeletal Muscles ◽  
Group Versus ◽  
The Body ◽  
Skeletal Muscle Function ◽  
Peripheral Tissues

Background. Acute heart failure (AHF) is associated with disturbances of the peripheral perfusion leading to the dysfunction of many organs. Consequently, an episode of AHF constitutes a “multiple organ failure” which may also affect the skeletal muscles. However, the abnormalities within skeletal muscles during AHF have not been investigated so far. The aim of this project is to comprehensively evaluate skeletal muscles (at a functional and tissue level) during AHF. Methods. The study will include ≥63 consecutive AHF patients who will be randomized into 2 groups: ≥42 with cardiac rehabilitation group versus ≥21 with standard pharmacotherapy alone. The following tests will be conducted on the first and last day of hospitalization, at rest and after exercise, and 30 days following the discharge: clinical evaluation, medical interview, routine physical examination, echocardiography, and laboratory tests (including the assessment of NT-proBNP, inflammatory markers, and parameters reflecting the status of the kidneys and the liver); hemodynamic evaluation, noninvasive determination of cardiac output and systemic vascular resistance using the impedance cardiography; evaluation of biomarkers reflecting myocyte damage, immunochemical measurements of tissue-specific enzymatic isoforms; evaluation of skeletal muscle function, using surface electromyography (sEMG) (maximum tonus of the muscles will be determined along with the level of muscular fatigability); evaluation of muscle tissue perfusion, assessed on the basis of the oxygenation level, with noninvasive direct continuous recording of perfusion in peripheral tissues by local tissue oximetry, measured by near-infrared spectroscopy (NIRS). Results and Conclusions. Our findings will demonstrate that the muscle tissue is another area of the body which should be taken into consideration in the course of treatment of AHF, requiring a development of targeted therapeutic strategies, such as a properly conducted rehabilitation.

scholarly journals Content of selected amino acids in the gastrocnemius muscle during experimental hypothyroidism in rats

2016 ◽  
Vol 60 (4) ◽  
pp. 489-493 ◽  
Author(s):  
Marcin Gołyński ◽  
Maria Szpetnar ◽  
Marcin R. Tatara ◽  
Krzysztof Lutnicki ◽  
Magdalena Gołyńska ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Muscle Function ◽  
Skeletal Muscles ◽  
Gastrocnemius Muscle ◽  
Amino Acid Content ◽  
Control Groups ◽  
Skeletal Muscle Function ◽  
Muscle Disorders ◽  
Induced Changes

Abstract Introduction: Thyroid hormones affect protein turnover, and in the case of hypothyroidism a decrease in protein synthesis and reduced release of certain amino acids from skeletal muscles are observed. Changes in the amino acid system of skeletal muscles may be responsible for the occurrence of muscle disorders. Material and Methods: The study measured the content of selected amino acids in the gastrocnemius muscle of Wistar rats during experimental hypothyroidism induced by oral administration of methimazole at a concentration of 0.05% in drinking water for 90 d. The rats were divided into four groups: E1 (n = 6) - experimental males, E2 (n = 6) - experimental females, C1 (n = 6) - control males, and C2 (n = 6) control females. Results: A statistically significant reduction occurred in leucine, isoleucine, and 1-methylhistidine levels in males, and 1-methylhistidine in females, in comparison to the control groups. Conclusion: The hypothyroidism-induced changes in amino acid content may be responsible for the occurrence of skeletal muscle function disorders.

scholarly journals Amino Acid Sensing in Metabolic Homeostasis and Health

2020 ◽  
Author(s):  
Xiaoming Hu ◽  
Feifan Guo
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Metabolic Regulation ◽  
Metabolic Diseases ◽  
Nutrient Sensing ◽  
The Body ◽  
Bioactive Molecules ◽  
Metabolic Homeostasis ◽  
Amino Acid Availability ◽  
Amino Acid Sensing

Abstract Sensing and responding to changes in nutrient levels, including those of glucose, lipids, and amino acids, by the body is necessary for survival. Accordingly, perturbations in nutrient sensing are tightly linked with human pathologies, particularly metabolic diseases such as obesity, type 2 diabetes mellitus, and other complications of metabolic syndromes. The conventional view is that amino acids are fundamental elements for protein and peptide synthesis, while recent studies have revealed that amino acids are also important bioactive molecules that play key roles in signaling pathways and metabolic regulation. Different pathways that sense intracellular and extracellular levels of amino acids are integrated and coordinated at the organismal level, and, together, these pathways maintain whole metabolic homeostasis. In this review, we discuss the studies describing how important sensing signals respond to amino acid availability and how these sensing mechanisms modulate metabolic processes, including energy, glucose, and lipid metabolism. We further discuss whether dysregulation of amino acid sensing signals can be targeted to promote metabolic disorders, and discuss how to translate these mechanisms to treat human diseases. This review will help to enhance our overall understanding of the correlation between amino acid sensing and metabolic homeostasis, which have important implications for human health.

scholarly journals Effect of pulmonary TNF-α overexpression on mouse isolated skeletal muscle function

2011 ◽  
Vol 301 (4) ◽  
pp. R1025-R1031 ◽  
Author(s):  
Li Zuo ◽  
Leonardo Nogueira ◽  
Michael C. Hogan
Keyword(s):  
Skeletal Muscle ◽  
Muscle Function ◽  
Weight Ratio ◽  
The Body ◽  
Chronic Obstructive ◽  
Skeletal Muscle Function ◽  
Muscle Weight ◽  
Peak Rate ◽  
Tnf Α

TNF-α is a proinflammatory cytokine that is involved in numerous pathological processes including chronic obstructive pulmonary disease (COPD). In the present study, we used a transgenic mouse model that overexpresses TNF-α in the lung (Tg+) to test the hypothesis that chronic exposure to TNF-α (as seen in COPD) reduces skeletal muscle force production and fatigue resistance, particularly under low Po2 conditions. At 7–12 mo, body and muscle weight of both extensor digitorum longus (EDL) and soleus were significantly smaller in Tg+ compared with littermate wild-type (WT) mice; however, the body-to-muscle weight ratio was not different between groups. EDL and soleus muscles were subjected to in vitro fatiguing contractile periods under high (∼550 Torr) and low Po2 (∼40 Torr). Although all muscles were less fatigue-resistant during low Po2 compared with high Po2, only the soleus fatigued more rapidly in Tg+ mice (∼12%) compared with WT at high Po2. The maximal tension of EDL was equally reduced in Tg+ mice (28–34% decrease from WT under both Po2 conditions); but for soleus this parameter was smaller only under low Po2 in Tg+ mice (∼31% decrease from WT). The peak rate of relaxation and the peak rate of contraction were both significantly reduced in Tg+ EDL muscles compared with WT EDL under low Po2 conditions, but not in soleus. These results demonstrate that TNF-α upregulation in the lung impairs peripheral skeletal muscle function but affects fast- and slow-twitch muscles differentially at high and low Po2.

Peptide Utilisation by the Mammary Gland of Lactating Goats

1993 ◽  
Vol 1993 ◽  
pp. 2-2
Author(s):  
F.R.C. Backwell ◽  
B.J. Bequette ◽  
A.G. Calder ◽  
J.A. Metcalf ◽  
D. Wray-Cahen ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Mammary Gland ◽  
Amino Acid ◽  
Milk Protein ◽  
The Body ◽  
Free Form ◽  
Small Proteins ◽  
Body Tissues ◽  
Lactating Goats

Most considerations of protein digestion assume that amino acids are made available to the body tissues as the free form but recent reports suggest that a substantial portion may be absorbed from the stomach region of ruminants as small peptides (1). However, the quantitative relevance of this absorption to amino acid supply to tissues remains unclear. We have previously indicated that in early lactation at least part of the amino acid supply to the lactating mammary gland may be met from blood derived peptides or small proteins (2) but at present there is no direct evidence to suggest that peptides can contribute amino acids to the gland for milk protein synthesis. However, it has been demonstrated in dairy animals that the uptake of certain amino acids across the mammary gland is insufficient to account for their output in milk protein (J.A. Metcalf, unpublished observation) and the possible utilisation of amino acids in ‘non-free’ form must be considered. The present study involves the use of a dual-labelled tracer approach to evaluate the ability of the mammary gland to utilise amino acids in peptide-bound form for milk protein synthesis. The technique involves infusion into the external pudic artery (EPA) supplying one half of die gland of a dipeptide XY where Y is a [13C]-labelled amino acid, coupled with a simultaneous (jugular) infusion of the amino acid Y but with a deuterium label. The jugular infusion allows a correction for recycled amino acid generated by whole animal (i.e. non-mammary) hydrolysis of the infused peptide. In theory if the half of the gland receiving direct infusion of the dipeptide utilises peptide-bound Y for milk protein synthesis then the ratio of [13C] : deuterium should be greater in casein secreted from that half of the gland compared with the other (control) side of the gland.

scholarly journals Putative imbalanced amino acid metabolism in rainbow trout long term fed a plant-based diet as revealed by 1H-NMR metabolomics

2021 ◽  
Vol 10 ◽  
Author(s):  
Catherine Deborde ◽  
Blandine Madji Hounoum ◽  
Annick Moing ◽  
Mickaël Maucourt ◽  
Daniel Jacob ◽  
...  
Keyword(s):  
Amino Acids ◽  
Rainbow Trout ◽  
Amino Acid ◽  
Amino Acid Content ◽  
Proton Nuclear Magnetic Resonance ◽  
Free Form ◽  
Metabolomic Analysis ◽  
Nmr Metabolomics ◽  
H Nmr

Abstract The long-term effect of a plant (P)-based diet was assessed by proton nuclear magnetic resonance (1H-NMR) metabolomics in rainbow trout fed a marine fish meal (FM)–fish oil (FO) diet (M), a P-based diet and a control commercial-like diet (C) starting with the first feeding. Growth performances were not heavily altered by long-term feeding on the P-based diet. An 1H-NMR metabolomic analysis of the feed revealed significantly different soluble chemical compound profiles between the diets. A set of soluble chemical compounds was found to be specific either to the P-based diet or to the M diet. Pterin, a biomarker of plant feedstuffs, was identified both in the P-based diet and in the plasma of fish fed the P-based diet. 1H-NMR metabolomic analysis on fish plasma and liver and muscle tissues at 6 and 48 h post feeding revealed significantly different profiles between the P-based diet and the M diet, while the C diet showed intermediate results. A higher amino acid content was found in the plasma of fish fed the P-based diet compared with the M diet after 48 h, suggesting either a delayed delivery of the amino acids or a lower amino acid utilisation in the P-based diet. This was associated with an accumulation of essential amino acids and the depletion of glutamine in the muscle, together with an accumulation of choline in the liver. Combined with an anticipated absorption of methionine and lysine supplemented in free form, the present results suggest an imbalanced essential amino acid supply for protein metabolism in the muscle and for specific functions of the liver.

scholarly journals Gait disturbances and muscle dysfunction in fibroblast growth factor 2 knockout mice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. Homer-Bouthiette ◽  
L. Xiao ◽  
Marja M. Hurley
Keyword(s):  
Skeletal Muscle ◽  
Growth Factor ◽  
Muscle Strength ◽  
Fibroblast Growth Factor ◽  
Muscle Function ◽  
Fibroblast Growth Factor 2 ◽  
Fibroblast Growth ◽  
Skeletal Muscle Function ◽  
Age Related ◽  
Gait Disturbances

AbstractFibroblast growth factor 2 (FGF2) is important in musculoskeletal homeostasis, therefore the impact of reduction or Fgf2 knockout on skeletal muscle function and phenotype was determined. Gait analysis as well as muscle strength testing in young and old WT and Fgf2KO demonstrated age-related gait disturbances and reduction in muscle strength that were exacerbated in the KO condition. Fgf2 mRNA and protein were significantly decreased in skeletal muscle of old WT compared with young WT. Muscle fiber cross-sectional area was significantly reduced with increased fibrosis and inflammatory infiltrates in old WT and Fgf2KO vs. young WT. Inflammatory cells were further significantly increased in old Fgf2KO compared with old WT. Lipid-related genes and intramuscular fat was increased in old WT and old Fgf2KO with a further increase in fibro-adipocytes in old Fgf2KO compared with old WT. Impaired FGF signaling including Increased β-Klotho, Fgf21 mRNA, FGF21 protein, phosphorylated FGF receptors 1 and 3, was observed in old WT and old Fgf2KO. MAPK/ ERK1/2 was significantly increased in young and old Fgf2KO. We conclude that Fgf2KO, age-related decreased FGF2 in WT mice, and increased FGF21 in the setting of impaired Fgf2 expression likely contribute to impaired skeletal muscle function and sarcopenia in mice.

scholarly journals Fourteen days of smoking cessation improves muscle fatigue resistance and reverses markers of systemic inflammation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohammad Z. Darabseh ◽  
Thomas M. Maden-Wilkinson ◽  
George Welbourne ◽  
Rob C. I. Wüst ◽  
Nessar Ahmed ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Skeletal Muscle ◽  
Smoking Cessation ◽  
Muscle Fatigue ◽  
Fatigue Resistance ◽  
Systemic Inflammation ◽  
Muscle Function ◽  
Low Grade ◽  
Skeletal Muscle Function ◽  
Tnf Α

AbstractCigarette smoking has a negative effect on respiratory and skeletal muscle function and is a risk factor for various chronic diseases. To assess the effects of 14 days of smoking cessation on respiratory and skeletal muscle function, markers of inflammation and oxidative stress in humans. Spirometry, skeletal muscle function, circulating carboxyhaemoglobin levels, advanced glycation end products (AGEs), markers of oxidative stress and serum cytokines were measured in 38 non-smokers, and in 48 cigarette smokers at baseline and after 14 days of smoking cessation. Peak expiratory flow (p = 0.004) and forced expiratory volume in 1 s/forced vital capacity (p = 0.037) were lower in smokers compared to non-smokers but did not change significantly after smoking cessation. Smoking cessation increased skeletal muscle fatigue resistance (p < 0.001). Haemoglobin content, haematocrit, carboxyhaemoglobin, total AGEs, malondialdehyde, TNF-α, IL-2, IL-4, IL-6 and IL-10 (p < 0.05) levels were higher, and total antioxidant status (TAS), IL-12p70 and eosinophil numbers were lower (p < 0.05) in smokers. IL-4, IL-6, IL-10 and IL-12p70 had returned towards levels seen in non-smokers after 14 days smoking cessation (p < 0.05), and IL-2 and TNF-α showed a similar pattern but had not yet fully returned to levels seen in non-smokers. Haemoglobin, haematocrit, eosinophil count, AGEs, MDA and TAS did not significantly change with smoking cessation. Two weeks of smoking cessation was accompanied with an improved muscle fatigue resistance and a reduction in low-grade systemic inflammation in smokers.

scholarly journals 146 Prematurity Blunts the Protein Synthetic Response of Skeletal Muscle to Insulin and Amino Acids

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 118-119
Author(s):  
Teresa A Davis ◽  
Marko Rudar ◽  
Jane Naberhuis ◽  
Agus Suryawan ◽  
Marta Fiorotto
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Body Weight Gain ◽  
Human Infant ◽  
Long Term Effects ◽  
Plasma Insulin Concentration ◽  
Akt Phosphorylation ◽  
Relative Body Weight

Abstract Livestock animals are important dual-purpose models that benefit both agricultural and biomedical research. The neonatal pig is an appropriate model for the human infant to assess long-term effects of early life nutrition on growth and metabolic outcomes. Previously we have demonstrated that prematurity blunts the feeding-induced stimulation of translation initiation and protein synthesis in skeletal muscle of neonatal pigs. The objective of this study was to determine whether reduced sensitivity to insulin and/or amino acids drives this blunted response. Pigs were delivered by caesarean section at preterm (PT, 103 d gestation) or at term (T, 112 d gestation) and fed parenterally for 4 d. On day 4, pigs were subject to euinsulinemic-euaminoacidemic-euglycemic (FAST), hyperinsulinemic-euaminoacidemic-euglycemic (INS), or euinsulinemic-hyperaminoacidemic-euglycemic (AA) clamps for 120 min, yielding six treatments: PT-FAST (n = 7), PT-INS (n = 9), PT-AA (n = 9), T-FAST (n = 8), T-INS (n = 9), and T-AA (n = 9). A flooding dose of L-[4-3H]Phe was injected into pigs 30 min before euthanasia. Birth weight and relative body weight gain were lower in PT than T pigs (P &lt; 0.001). Plasma insulin concentration was increased from ~3 to ~100 µU/mL in INS compared to FAST and AA pigs (P &lt; 0.001); plasma BCAA concentration was increased from ~250 to ~1,000 µmol/L in AA compared to FAST and INS pigs (P &lt; 0.001). Despite achieving similar insulin and amino acid levels, longissimus dorsi AKT phosphorylation, mechanistic target of rapamycin (mTOR)·Rheb abundance, mTOR activation, and protein synthesis were lower in PT-INS than T-INS pigs (Table 1). Although amino-acid induced dissociation of Sestrin2 from GATOR2 was not affected by prematurity, mTOR·RagA abundance, mTOR·RagC abundance, mTOR activation, and protein synthesis were lower in PT-AA than T-AA pigs. The impaired capacity of premature skeletal muscle to respond to insulin or amino acids and promote protein synthesis likely contributes to reduced lean mass accretion. Research was supported by NIH and USDA.

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