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Tekwe CD, Luan Y, Meininger CJ, Bazer FW, Wu G. Dietary supplementation with L-leucine reduces nitric oxide synthesis by endothelial cells of rats. Exp Biol Med (Maywood) 2023; 248:1537-1549. [PMID: 37837386 PMCID: PMC10676130 DOI: 10.1177/15353702231199078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 07/21/2023] [Indexed: 10/16/2023] Open
Abstract
This study tested the hypothesis that elevated L-leucine concentrations in plasma reduce nitric oxide (NO) synthesis by endothelial cells (ECs) and affect adiposity in obese rats. Beginning at four weeks of age, male Sprague-Dawley rats were fed a casein-based low-fat (LF) or high-fat (HF) diet for 15 weeks. Thereafter, rats in the LF and HF groups were assigned randomly into one of two subgroups (n = 8/subgroup) and received drinking water containing either 1.02% L-alanine (isonitrogenous control) or 1.5% L-leucine for 12 weeks. The energy expenditure of the rats was determined at weeks 0, 6, and 11 of the supplementation period. At the end of the study, an oral glucose tolerance test was performed on all the rats immediately before being euthanized for the collection of tissues. HF feeding reduced (P < 0.001) NO synthesis in ECs by 21% and whole-body insulin sensitivity by 19% but increased (P < 0.001) glutamine:fructose-6-phosphate transaminase (GFAT) activity in ECs by 42%. Oral administration of L-leucine decreased (P < 0.05) NO synthesis in ECs by 14%, increased (P < 0.05) GFAT activity in ECs by 35%, and reduced (P < 0.05) whole-body insulin sensitivity by 14% in rats fed the LF diet but had no effect (P > 0.05) on these variables in rats fed the HF diet. L-Leucine supplementation did not affect (P > 0.05) weight gain, tissue masses (including white adipose tissue, brown adipose tissue, and skeletal muscle), or antioxidative capacity (indicated by ratios of glutathione/glutathione disulfide) in LF- or HF-fed rats and did not worsen (P > 0.05) adiposity, whole-body insulin sensitivity, or metabolic profiles in the plasma of obese rats. These results indicate that high concentrations of L-leucine promote glucosamine synthesis and impair NO production by ECs, possibly contributing to an increased risk of cardiovascular disease in diet-induced obese rats.
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Affiliation(s)
- Carmen D Tekwe
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
- Department of Epidemiology and Biostatistics, Texas A&M University, College Station, TX 77843, USA
- Department of Epidemiology and Biostatistics, School of Public Health, Indiana University, Bloomington, IN 47403, USA
| | - Yuanyuan Luan
- Department of Epidemiology and Biostatistics, Texas A&M University, College Station, TX 77843, USA
- Department of Epidemiology and Biostatistics, School of Public Health, Indiana University, Bloomington, IN 47403, USA
| | - Cynthia J Meininger
- Department of Medical Physiology, Texas A&M University, College Station, TX 77843, USA
| | - Fuller W Bazer
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
| | - Guoyao Wu
- Department of Animal Science, Texas A&M University, College Station, TX 77843, USA
- Department of Medical Physiology, Texas A&M University, College Station, TX 77843, USA
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2
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Aragon AA, Tipton KD, Schoenfeld BJ. Age-related muscle anabolic resistance: inevitable or preventable? Nutr Rev 2023; 81:441-454. [PMID: 36018750 DOI: 10.1093/nutrit/nuac062] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Age-related loss of muscle mass, strength, and performance, commonly referred to as sarcopenia, has wide-ranging detrimental effects on human health, the ramifications of which can have serious implications for both morbidity and mortality. Various interventional strategies have been proposed to counteract sarcopenia, with a particular emphasis on those employing a combination of exercise and nutrition. However, the efficacy of these interventions can be confounded by an age-related blunting of the muscle protein synthesis response to a given dose of protein/amino acids, which has been termed "anabolic resistance." While the pathophysiology of sarcopenia is undoubtedly complex, anabolic resistance is implicated in the progression of age-related muscle loss and its underlying complications. Several mechanisms have been proposed as underlying age-related impairments in the anabolic response to protein consumption. These include decreased anabolic molecular signaling activity, reduced insulin-mediated capillary recruitment (thus, reduced amino acid delivery), and increased splanchnic retention of amino acids (thus, reduced availability for muscular uptake). Obesity and sedentarism can exacerbate, or at least facilitate, anabolic resistance, mediated in part by insulin resistance and systemic inflammation. This narrative review addresses the key factors and contextual elements involved in reduction of the acute muscle protein synthesis response associated with aging and its varied consequences. Practical interventions focused on dietary protein manipulation are proposed to prevent the onset of anabolic resistance and mitigate its progression.
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Affiliation(s)
- Alan A Aragon
- is with the Department of Family and Consumer Sciences, California State University, Northridge, California, USA
| | - Kevin D Tipton
- is with the Institute of Performance Nutrition, Edinburgh, Scotland
| | - Brad J Schoenfeld
- is with the Department of Health Sciences, CUNY Lehman College, Bronx, New York, USA
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3
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Acute effects of prior dietary fat ingestion on postprandial metabolic responses to protein and carbohydrate co-ingestion in overweight and obese men: A randomised crossover trial. Clin Nutr 2022; 41:1623-1635. [PMID: 35764009 DOI: 10.1016/j.clnu.2022.06.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 06/07/2022] [Accepted: 06/10/2022] [Indexed: 11/22/2022]
Abstract
BACKGROUND Obesity and insulin resistance are associated with an impaired sensitivity to anabolic stimuli such as dietary protein (anabolic resistance). Omega-3 polyunsaturated fatty acids (n-3 PUFA) may be protective against the deleterious effects of saturated fatty acids (SFA) on insulin resistance. However, the contribution of excess fat consumption to anabolic and insulin resistance and the interaction between SFA and n-3 PUFA is not well studied. AIM The primary aim of this study was to investigate the effects of an oral fat pre-load, with or without the partial substitution of SFA with fish oil (FO)-derived n-3 PUFA, on indices of insulin and anabolic sensitivity in response to subsequent dietary protein and carbohydrate (dextrose) co-ingestion. METHODS Eight middle-aged males with overweight or obesity (52.8 ± 2.0 yr, BMI 31.8 ± 1.4 kg·m-2) ingested either an SFA, or isoenergetic SFA and FO emulsion (FO), or water/control (Con), 4 h prior to a bolus of milk protein and dextrose. RESULTS Lipid ingestion (in particular FO) impaired the early postprandial uptake of branched chain amino acids (BCAA) into the skeletal muscle in response to protein and dextrose, and attenuated the peak glycaemic response, but was not accompanied by differences in whole body (Matsuda Index: Con: 4.66 ± 0.89, SFA: 5.10 ± 0.94 and FO: 4.07 ± 0.59) or peripheral (forearm glucose netAUC: Con: 521.7 ± 101.7; SFA: 470.2 ± 125.5 and FO: 495.3 ± 101.6 μmol·min-1·100 g lean mass·min [t = 240-420 min]) insulin sensitivity between visits. Postprandial whole body fat oxidation was affected by visit (P = 0.024) with elevated rates in SFA and FO, relative to Con (1.85 ± 0.55; 2.19 ± 0.21 and 0.65 ± 0.35 kJ·h-1·kg-1 lean body mass, respectively), however muscle uptake of free fatty acids (FFA) was unaffected. CONCLUSION Oral lipid preloads, consisting of SFA and FO, impair the early postprandial BCAA uptake into skeletal muscle, which occurs independent of changes in insulin sensitivity. CLINICAL TRIAL REGISTRY NUMBER ClinicalTrials.gov Identifier NCT03146286.
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4
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Freitas EDS, Katsanos CS. (Dys)regulation of Protein Metabolism in Skeletal Muscle of Humans With Obesity. Front Physiol 2022; 13:843087. [PMID: 35350688 PMCID: PMC8957804 DOI: 10.3389/fphys.2022.843087] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 02/07/2022] [Indexed: 01/22/2023] Open
Abstract
Studies investigating the proteome of skeletal muscle present clear evidence that protein metabolism is altered in muscle of humans with obesity. Moreover, muscle quality (i.e., strength per unit of muscle mass) appears lower in humans with obesity. However, relevant evidence to date describing the protein turnover, a process that determines content and quality of protein, in muscle of humans with obesity is quite inconsistent. This is due, at least in part, to heterogeneity in protein turnover in skeletal muscle of humans with obesity. Although not always evident at the mixed-muscle protein level, the rate of synthesis is generally lower in myofibrillar and mitochondrial proteins in muscle of humans with obesity. Moreover, alterations in the synthesis of protein in muscle of humans with obesity are manifested more readily under conditions that stimulate protein synthesis in muscle, including the fed state, increased plasma amino acid availability to muscle, and exercise. Current evidence supports various biological mechanisms explaining impairments in protein synthesis in muscle of humans with obesity, but this evidence is rather limited and needs to be reproduced under more defined experimental conditions. Expanding our current knowledge with direct measurements of protein breakdown in muscle, and more importantly of protein turnover on a protein by protein basis, will enhance our understanding of how obesity modifies the proteome (content and quality) in muscle of humans with obesity.
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Affiliation(s)
| | - Christos S Katsanos
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.,Department of Physiology and Biomedical Engineering, Mayo Clinic in Arizona, Scottsdale, AZ, United States
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5
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Paulussen KJM, McKenna CF, Beals JW, Wilund KR, Salvador AF, Burd NA. Anabolic Resistance of Muscle Protein Turnover Comes in Various Shapes and Sizes. Front Nutr 2021; 8:615849. [PMID: 34026802 PMCID: PMC8131552 DOI: 10.3389/fnut.2021.615849] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 03/01/2021] [Indexed: 12/18/2022] Open
Abstract
Anabolic resistance is defined by a blunted stimulation of muscle protein synthesis rates (MPS) to common anabolic stimuli in skeletal muscle tissue such as dietary protein and exercise. Generally, MPS is the target of most exercise and feeding interventions as muscle protein breakdown rates seem to be less responsive to these stimuli. Ultimately, the blunted responsiveness of MPS to dietary protein and exercise underpins the loss of the amount and quality of skeletal muscle mass leading to decrements in physical performance in these populations. The increase of both habitual physical activity (including structured exercise that targets general fitness characteristics) and protein dense food ingestion are frontline strategies utilized to support muscle mass, performance, and health. In this paper, we discuss anabolic resistance as a common denominator underpinning muscle mass loss with aging, obesity, and other disease states. Namely, we discuss the fact that anabolic resistance exists as a dimmer switch, capable of varying from higher to lower levels of resistance, to the main anabolic stimuli of feeding and exercise depending on the population. Moreover, we review the evidence on whether increased physical activity and targeted exercise can be leveraged to restore the sensitivity of skeletal muscle tissue to dietary amino acids regardless of the population.
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Affiliation(s)
- Kevin J. M. Paulussen
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Colleen F. McKenna
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Joseph W. Beals
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, United States
| | - Kenneth R. Wilund
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Amadeo F. Salvador
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Nicholas A. Burd
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, United States
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6
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Stokes SM, Stefanovski D, Bertin FR, Medina-Torres CE, Belknap JK, van Eps AW. Plasma amino acid concentrations during experimental hyperinsulinemia in 2 laminitis models. J Vet Intern Med 2021; 35:1589-1596. [PMID: 33704816 PMCID: PMC8163125 DOI: 10.1111/jvim.16095] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 02/14/2021] [Accepted: 02/19/2021] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Endocrinopathic laminitis develops in association with insulin dysregulation, but the role of insulin in the pathogenesis remains unclear. Hyperinsulinemia can cause hypoaminoacidemia, which is associated with integumentary lesions in other species and therefore warrants investigation as a potential mechanism in laminitis. OBJECTIVE Evaluate plasma amino acid concentrations in the euglycemic-hyperinsulinemic clamp (EHC) and prolonged glucose infusion (PGI) laminitis models. ANIMALS Sixteen Standardbred horses. METHODS Prospective experimental study. Plasma amino acid concentrations were measured in samples collected every 6 hours from horses that underwent a 48-hour EHC (n = 8) or 66-hour PGI (n = 8) after a 24- or 6-hour baseline period in EHC and PGI groups, respectively. RESULTS Fifteen of the 20 measured amino acid concentrations decreased over time in both EHC and PGI horses (P < 0.001). The median percentage change from baseline for these amino acids was: histidine (EHC: 41.5%; PGI: 43.9%), glutamine (EHC: 51.8%; PGI: 35.3%), arginine (EHC: 51.4%; PGI: 41%), glutamic acid (EHC: 52.4%; PGI: 31.7%), threonine (EHC: 62.8%; PGI: 25.2%), alanine (EHC: 48.9%; PGI: 19.5%), proline (EHC: 56.2%; PGI: 30.3%), cystine (EHC: 34.9%; PGI: 31.2%), lysine (EHC: 46.4%; PGI: 27.8%), tyrosine (EHC: 27.5%; PGI: 16.9%), methionine (EHC: 69.3%; PGI: 50.8%), valine (EHC: 50.8%; PGI: 34.4%), isoleucine (EHC: 60.8%; PGI: 38.7%), leucine (EHC: 48.2%; PGI: 36.6%), and phenylalanine (EHC: 16.6%; PGI: 12.1%). CONCLUSIONS AND CLINICAL IMPORTANCE Hypoaminoacidemia develops in EHC and PGI laminitis models. The role of hypoaminoacidemia in the development of hyperinsulinemia-associated laminitis warrants further investigation.
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Affiliation(s)
- Simon M Stokes
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Darko Stefanovski
- Department of Clinical Studies, School of Veterinary Medicine, New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
| | - François-René Bertin
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - Carlos E Medina-Torres
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia
| | - James K Belknap
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio, USA
| | - Andrew W van Eps
- Australian Equine Laminitis Research Unit, School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.,Department of Clinical Studies, School of Veterinary Medicine, New Bolton Center, University of Pennsylvania, Kennett Square, Pennsylvania, USA
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7
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Mantha OL, Huneau JF, Mathé V, Hermier D, Khodorova N, Mariotti F, Fouillet H. Differential changes to splanchnic and peripheral protein metabolism during the diet-induced development of metabolic syndrome in rats. Am J Physiol Endocrinol Metab 2020; 319:E175-E186. [PMID: 32459526 DOI: 10.1152/ajpendo.00061.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is known about the effects of the development of metabolic syndrome (MS) on protein and amino acid (AA) metabolism. During this study, we took advantage of the variability in interindividual susceptibility to high fat diet-induced MS to study the relationships between MS, protein synthesis, and AA catabolism in multiple tissues in rats. After 4 mo of high-fat feeding, an MS score (ZMS) was calculated as the average of the z-scores for individual MS components [weight, adiposities, homeostasis model for the assessment of insulin resistance (HOMA-IR), and triglycerides]. In the small intestine, liver, plasma, kidneys, heart, and muscles, tissue protein synthesis was measured by 2H2O labeling, and we evaluated the proportion of tissue AA catabolism (relative to protein synthesis) and nutrient routing to nonindispensable AAs in tissue proteins using natural nitrogen and carbon isotopic distances between tissue proteins and nutrients (Δ15N and Δ13C), respectively. In the liver, protein mass and synthesis increased, whereas the proportion of AA catabolism decreased with ZMS. By contrast, in muscles, we found no association between ZMS and protein mass, protein synthesis (except for a weak positive association in the gastrocnemius muscle only), and proportion of AA catabolism. The development of MS was also associated with altered metabolic flexibility and fatty acid oxidation, as shown by less routing of dietary lipids to nonindispensable AA synthesis in liver and muscle. In conclusion, MS development is associated with a greater gain of both fat and protein masses, with higher protein anabolism that mainly occurs in the liver, whereas muscles probably develop anabolic resistance due to insulin resistance.
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Affiliation(s)
- O L Mantha
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - J-F Huneau
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - V Mathé
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - D Hermier
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - N Khodorova
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - F Mariotti
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
| | - H Fouillet
- Université Paris-Saclay, AgroParisTech, INRAE, UMR PNCA, 75005, Paris, France
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8
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Edick AM, Auclair O, Burgos SA. Role of Grb10 in mTORC1-dependent regulation of insulin signaling and action in human skeletal muscle cells. Am J Physiol Endocrinol Metab 2020; 318:E173-E183. [PMID: 31794259 DOI: 10.1152/ajpendo.00025.2019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Growth factor receptor-bound protein 10 (Grb10) is an adaptor protein that binds to the insulin receptor, upon which insulin signaling and action are thought to be inhibited. Grb10 is also a substrate for the mechanistic target of rapamycin complex 1 (mTORC1) that mediates its feedback inhibition on phosphatidylinositide 3-kinase (PI3K)/Akt signaling. To characterize the function of Grb10 and its regulation by mTORC1 in human muscle, primary skeletal muscle cells were isolated from healthy lean young men and then induced to differentiate into myotubes. Knockdown of Grb10 enhanced insulin-induced PI3K/Akt signaling and glucose uptake in myotubes, reinforcing the notion underlying its function as a negative regulator of insulin action in human muscle. The increased insulin responsiveness in Grb10-silenced myotubes was associated with a higher abundance of the insulin receptor. Furthermore, insulin and amino acids independently and additively stimulated phosphorylation of Grb10 at Ser476. However, acute inhibition of mTORC1 with rapamycin blocked Grb10 Ser476 phosphorylation and repressed a negative-feedback loop on PI3K/Akt signaling that increased myotube responsiveness to insulin. Chronic rapamycin treatment reduced Grb10 protein abundance in conjunction with increased insulin receptor protein levels. Based on these findings, we propose that mTORC1 controls PI3K/Akt signaling through modulation of insulin receptor abundance by Grb10. These findings have potential implications for obesity-linked insulin resistance, as well as clinical use of mTORC1 inhibitors.
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Affiliation(s)
- Ashlin M Edick
- Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Olivia Auclair
- Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Sergio A Burgos
- Department of Animal Science, McGill University, Sainte-Anne-de-Bellevue, Quebec, Canada
- Department of Medicine, McGill University, Montreal, Quebec, Canada
- Metabolic Disorders and Complications Program, Research Institute of McGill University Health Centre, Montreal, Quebec, Canada
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9
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Kouw IWK, van Dijk JW, Horstman AMH, Kramer IF, Goessens JPB, van Dielen FMH, Verdijk LB, van Loon LJC. Basal and Postprandial Myofibrillar Protein Synthesis Rates Do Not Differ between Lean and Obese Middle-Aged Men. J Nutr 2019; 149:1533-1542. [PMID: 31174213 PMCID: PMC6736155 DOI: 10.1093/jn/nxz104] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 02/28/2019] [Accepted: 04/25/2019] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Excess lipid availability has been associated with the development of anabolic resistance. As such, obesity may be accompanied by impairments in muscle protein metabolism. OBJECTIVE We hypothesized that basal and postprandial muscle protein synthesis rates are lower in obese than in lean men. METHODS Twelve obese men [mean ± SEM age: 48 ± 2 y; BMI (in kg/m2): 37.0 ± 1.5; body fat: 32 ± 2%] and 12 age-matched lean controls (age: 43 ± 3 y; BMI: 23.4 ± 0.4; body fat: 21 ± 1%) received primed continuous L-[ring-2H5]-phenylalanine and L-[ring-3,5-2H2]-tyrosine infusions and ingested 25 g intrinsically L-[1-13C]-phenylalanine labeled whey protein. Repeated blood and muscle samples were obtained to assess protein digestion and amino acid absorption kinetics, and basal and postprandial myofibrillar protein synthesis rates. RESULTS Exogenous phenylalanine appearance rates increased after protein ingestion in both groups (P < 0.001), with a total of 53 ± 1% and 53 ± 2% of dietary protein-derived phenylalanine appearing in the circulation over the 5-h postprandial period in lean and obese men, respectively (P = 0.82). After protein ingestion, whole-body protein synthesis and oxidation rates increased to a greater extent in lean men than in the obese (P-interaction < 0.05), resulting in a higher whole-body protein net balance in the lean than in the obese (7.1 ± 0.2 and 4.6 ± 0.4 µmol phenylalanine · h-1 · kg-1, respectively; P-interaction < 0.001). Myofibrillar protein synthesis rates increased from 0.030 ± 0.002 and 0.028 ± 0.003%/h in the postabsorptive period to 0.034 ± 0.002 and 0.035 ± 0.003%.h-1 in the 5-h postprandial period (P = 0.03) in lean and obese men, respectively, with no differences between groups (P-interaction = 0.58). CONCLUSIONS Basal, postabsorptive myofibrillar protein synthesis rates do not differ between lean and obese middle-aged men. Postprandial protein handling, including protein digestion and amino acid absorption, and the postprandial muscle protein synthetic response after the ingestion of 25 g whey protein are not impaired in obese men. This trial was registered at www.trialregister.nl as NTR4060.
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Affiliation(s)
- Imre W K Kouw
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Jan Willem van Dijk
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Astrid M H Horstman
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Irene Fleur Kramer
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Joy P B Goessens
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands
| | | | - Lex B Verdijk
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands
| | - Luc J C van Loon
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University Medical Centre+, Maastricht, Netherlands,Top Institute Food and Nutrition, Wageningen, Netherlands,Address correspondence to LJCvL (e-mail: )
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10
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Beals JW, Burd NA, Moore DR, van Vliet S. Obesity Alters the Muscle Protein Synthetic Response to Nutrition and Exercise. Front Nutr 2019; 6:87. [PMID: 31263701 PMCID: PMC6584965 DOI: 10.3389/fnut.2019.00087] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/23/2019] [Indexed: 12/17/2022] Open
Abstract
Improving the health of skeletal muscle is an important component of obesity treatment. Apart from allowing for physical activity, skeletal muscle tissue is fundamental for the regulation of postprandial macronutrient metabolism, a time period that represents when metabolic derangements are most often observed in adults with obesity. In order for skeletal muscle to retain its capacity for physical activity and macronutrient metabolism, its protein quantity and composition must be maintained through the efficient degradation and resynthesis for proper tissue homeostasis. Life-style behaviors such as increasing physical activity and higher protein diets are front-line treatment strategies to enhance muscle protein remodeling by primarily stimulating protein synthesis rates. However, the muscle of individuals with obesity appears to be resistant to the anabolic action of targeted exercise regimes and protein ingestion when compared to normal-weight adults. This indicates impaired muscle protein remodeling in response to the main anabolic stimuli to human skeletal muscle tissue is contributing to poor muscle health with obesity. Deranged anabolic signaling related to insulin resistance, lipid accumulation, and/or systemic/muscle inflammation are likely at the root of the anabolic resistance of muscle protein synthesis rates with obesity. The purpose of this review is to discuss the impact of protein ingestion and exercise on muscle protein remodeling in people with obesity, and the potential mechanisms underlining anabolic resistance of their muscle.
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Affiliation(s)
- Joseph W Beals
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, United States
| | - Nicholas A Burd
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Daniel R Moore
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, ON, Canada
| | - Stephan van Vliet
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, United States
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11
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Beals JW, Skinner SK, McKenna CF, Poozhikunnel EG, Farooqi SA, van Vliet S, Martinez IG, Ulanov AV, Li Z, Paluska SA, Burd NA. Altered anabolic signalling and reduced stimulation of myofibrillar protein synthesis after feeding and resistance exercise in people with obesity. J Physiol 2018; 596:5119-5133. [PMID: 30113718 DOI: 10.1113/jp276210] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 08/15/2018] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS Lifestyle modifications that include the regular performance of exercise are probably important for counteracting the negative consequences of obesity on postprandial myofibrillar protein synthetic responses to protein dense food ingestion. We show that the interactive effect of resistance exercise and feeding on the stimulation of myofibrillar protein synthesis rates is diminished with obesity compared to normal weight adults. The blunted myofibrillar protein synthetic response with resistance exercise in people with obesity may be underpinned by alterations in muscle anabolic signalling phosphorylation (p70S6K and 4E-BP1). The results obtained in the present study suggest that further exercise prescription manipulation may be necessary to optimize post-exercise myofibrillar protein synthesis rates in adults with obesity. ABSTRACT We aimed to determine whether obesity alters muscle anabolic and inflammatory signalling phosphorylation and also muscle protein synthesis within the myofibrillar (MYO) and sarcoplasmic (SARC) protein fractions after resistance exercise. Nine normal weight (NW) (21 ± 1 years, body mass index 22 ± 1 kg m-2 ) and nine obese (OB) (22 ± 1 years, body mass index 36 ± 2 kg m-2 ) adults received l-[ring-13 C6 ]phenylalanine infusions with blood and muscle sampling at basal and fed-state of the exercise (EX) and non-exercise (CON) legs. Participants performed unilateral leg extensions and consumed pork (36 g of protein) immediately after exercise. Basal muscle Toll-like receptor 4 (TLR4) protein was similar between OB and NW groups (P > 0.05) but increased at 300 min after pork ingestion only in the OB group (P = 0.03). Resistance exercise reduced TLR4 protein in the OB group at 300 min (EX vs. CON leg in OB: P = 0.04). Pork ingestion increased p70S6K phosphorylation at 300 min in CON and EX of the OB and NW groups (P > 0.05), although the response was lower in the EX leg of OB vs. NW at 300 min (P = 0.05). Basal MYO was similar between the NW and OB groups (P > 0.05) and was stimulated by pork ingestion in the EX and CON legs in both groups (Δ from basal NW: CON 0.04 ± 0.01% h-1 ; EX 0.10 ± 0.02% h-1 ; OB: CON 0.06 ± 0.01% h-1 ; EX 0.06 ± 0.01% h-1 ; P < 0.05). MYO was more strongly stimulated in the EX vs. CON legs in NW (P = 0.02) but not OB (P = 0.26). SARC was feeding sensitive but not further potentiated by resistance exercise in both groups. Our results suggest that obesity may attenuate the effectiveness of resistance exercise to augment fed-state MYO.
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Affiliation(s)
- Joseph W Beals
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Sarah K Skinner
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Colleen F McKenna
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Elizabeth G Poozhikunnel
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Samee A Farooqi
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Stephan van Vliet
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Isabel G Martinez
- Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Alexander V Ulanov
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Zhong Li
- Roy J. Carver Biotechnology Center, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Scott A Paluska
- Department of Family Medicine, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicholas A Burd
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA.,Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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12
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Fazakerley DJ, Krycer JR, Kearney AL, Hocking SL, James DE. Muscle and adipose tissue insulin resistance: malady without mechanism? J Lipid Res 2018; 60:1720-1732. [PMID: 30054342 DOI: 10.1194/jlr.r087510] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/25/2018] [Indexed: 12/14/2022] Open
Abstract
Insulin resistance is a major risk factor for numerous diseases, including type 2 diabetes and cardiovascular disease. These disorders have dramatically increased in incidence with modern life, suggesting that excess nutrients and obesity are major causes of "common" insulin resistance. Despite considerable effort, the mechanisms that contribute to common insulin resistance are not resolved. There is universal agreement that extracellular perturbations, such as nutrient excess, hyperinsulinemia, glucocorticoids, or inflammation, trigger intracellular stress in key metabolic target tissues, such as muscle and adipose tissue, and this impairs the ability of insulin to initiate its normal metabolic actions in these cells. Here, we present evidence that the impairment in insulin action is independent of proximal elements of the insulin signaling pathway and is likely specific to the glucoregulatory branch of insulin signaling. We propose that many intracellular stress pathways act in concert to increase mitochondrial reactive oxygen species to trigger insulin resistance. We speculate that this may be a physiological pathway to conserve glucose during specific states, such as fasting, and that, in the presence of chronic nutrient excess, this pathway ultimately leads to disease. This review highlights key points in this pathway that require further research effort.
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Affiliation(s)
- Daniel J Fazakerley
- School of Life and Environmental Sciences, Central Clinical School, University of Sydney, Camperdown, New South Wales, Australia
| | - James R Krycer
- School of Life and Environmental Sciences, Central Clinical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Alison L Kearney
- School of Life and Environmental Sciences, Central Clinical School, University of Sydney, Camperdown, New South Wales, Australia
| | - Samantha L Hocking
- Faculty of Medicine and Health, University of Sydney, Camperdown, New South Wales, Australia
| | - David E James
- School of Life and Environmental Sciences, Central Clinical School, University of Sydney, Camperdown, New South Wales, Australia .,Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, New South Wales, Australia
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13
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Tran L, Kras KA, Hoffman N, Ravichandran J, Dickinson JM, D’Lugos A, Carroll CC, Patel SH, Mandarino LJ, Roust L, Katsanos CS. Lower Fasted-State but Greater Increase in Muscle Protein Synthesis in Response to Elevated Plasma Amino Acids in Obesity. Obesity (Silver Spring) 2018; 26:1179-1187. [PMID: 29896930 PMCID: PMC6078204 DOI: 10.1002/oby.22213] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Obesity alters protein metabolism in skeletal muscle, but consistent evidence is lacking. This study compared muscle protein synthesis in adults with obesity and in lean controls in the fasted state and during an amino acid infusion. METHODS Ten subjects with obesity (age: 36 ± 3 years; BMI: 34 ± 1 kg/m2 ) and ten controls (age: 35 ± 3 years; BMI: 23 ± 1 kg/m2 ) received an infusion of L-[2,3,3,4,5,5,5,6,6,6-2 H10 ]leucine (0.15 μmol/kg fat-free mass/min) to measure muscle protein synthesis after an overnight fast and during amino acid infusion. RESULTS Despite greater muscle mammalian target of rapamycin phosphorylation (P ≤ 0.05), fasted-state mixed-muscle and mitochondrial protein synthesis were lower in subjects with obesity (P ≤ 0.05). However, the change in mixed-muscle protein synthesis during the amino acid infusion was 2.7-fold greater in subjects with obesity (P ≤ 0.05), accompanied by a greater change in S6 kinase-1 phosphorylation (P ≤ 0.05). The change in mitochondrial protein synthesis did not differ between groups (P > 0.05). CONCLUSIONS Adults with obesity have reduced muscle protein synthesis in the fasted state, but this response is compensated for by a greater change in overall muscle protein synthesis during amino acid infusion.
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Affiliation(s)
- Lee Tran
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ
| | - Katon A. Kras
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ
| | - Nyssa Hoffman
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ
| | | | - Jared M. Dickinson
- School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ
| | - Andrew D’Lugos
- School of Nutrition and Health Promotion, Arizona State University, Phoenix, AZ
| | - Chad C. Carroll
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN
| | - Shivam H. Patel
- Department of Health and Kinesiology, Purdue University, West Lafayette, IN
| | - Lawrence J. Mandarino
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ
- College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ
| | - Lori Roust
- College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ
| | - Christos S. Katsanos
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, AZ
- College of Medicine, Mayo Clinic in Arizona, Scottsdale, AZ
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14
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Chen W, Jiang H, Yang JX, Yang H, Liu JM, Zhen XY, Feng LJ, Yu JC. Body Composition Analysis by Using Bioelectrical Impedance in a Young Healthy Chinese Population: Methodological Considerations. Food Nutr Bull 2017; 38:172-181. [PMID: 28513264 DOI: 10.1177/0379572117697534] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE To develop a new bioelectrical impedance analysis (BIA) model for analyzing body composition by using isotope dilution, magnetic resonance imaging (MRI), and dual-energy X-ray absorptiometry (DEXA) as the reference methods in young healthy Chinese populations. METHODS Thirty healthy participants were enrolled. Their body composition was analyzed using BIA and 3 reference methods. We established a model that uniformed data from 3 references methods (isotope, MRI, and DEXA) into 1 formula. This model was further validated with 209 participants. RESULTS The following BIA body composition adjustment model was developed: [Formula: see text], where X represents the impedance index; when K = 1, 2, and 3, Y represents total body water, fat mass, and bone mass, respectively. The prediction accuracy of this formula was 93.3%. By incorporating the data matrix, the protein mass was calculated using BIA: [Formula: see text]. In the verification part of this study, the lean body mass measured using DEXA and BIA was 43.02 ± 8.34 kg and 45.85 ± 8.81 kg, respectively. Analysis indicated that the model fit was extremely favorable ( R2 = .9997, P < .001). CONCLUSIONS The accuracy of BIA measurement on body composition and protein mass is significantly improved by our work.
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Affiliation(s)
- Wei Chen
- 1 Department of Enteral and Parenteral Nutrition, Peking Union Medical College Hospital, Medical School of Tsinghua University, Beijing, China
| | - Hua Jiang
- 1 Department of Enteral and Parenteral Nutrition, Peking Union Medical College Hospital, Medical School of Tsinghua University, Beijing, China.,2 Department of Computational Mathematics and Biostatistics, Metabolomics and Multidisciplinary Laboratory for Trauma Research, Sichuan Provincial People's Hospital and Sichuan Academy of Medical Sciences, Chengdu, China
| | - Jiong-Xian Yang
- 1 Department of Enteral and Parenteral Nutrition, Peking Union Medical College Hospital, Medical School of Tsinghua University, Beijing, China
| | - Hao Yang
- 2 Department of Computational Mathematics and Biostatistics, Metabolomics and Multidisciplinary Laboratory for Trauma Research, Sichuan Provincial People's Hospital and Sichuan Academy of Medical Sciences, Chengdu, China
| | - Jing-Min Liu
- 3 Department of Sports, Tsinghua University, Beijing, China
| | - Xiu-Yuan Zhen
- 3 Department of Sports, Tsinghua University, Beijing, China
| | - Lian-Jun Feng
- 4 Stable Isotope Laboratory of Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
| | - Jian-Chun Yu
- 5 Department of General Surgery, Peking Union Medical College Hospital, Medical School of Tsinghua University, Beijing, China
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15
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Everman S, Meyer C, Tran L, Hoffman N, Carroll CC, Dedmon WL, Katsanos CS. Insulin does not stimulate muscle protein synthesis during increased plasma branched-chain amino acids alone but still decreases whole body proteolysis in humans. Am J Physiol Endocrinol Metab 2016; 311:E671-E677. [PMID: 27530230 PMCID: PMC5241558 DOI: 10.1152/ajpendo.00120.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 08/10/2016] [Indexed: 01/19/2023]
Abstract
Insulin stimulates muscle protein synthesis when the levels of total amino acids, or at least the essential amino acids, are at or above their postabsorptive concentrations. Among the essential amino acids, branched-chain amino acids (BCAA) have the primary role in stimulating muscle protein synthesis and are commonly sought alone to stimulate muscle protein synthesis in humans. Fourteen healthy young subjects were studied before and after insulin infusion to examine whether insulin stimulates muscle protein synthesis in relation to the availability of BCAA alone. One half of the subjects were studied in the presence of postabsorptive BCAA concentrations (control) and the other half in the presence of increased plasma BCAA (BCAA). Compared with that prior to the initiation of the insulin infusion, fractional synthesis rate of muscle protein (%/h) did not change (P > 0.05) during insulin in either the control (0.04 ± 0.01 vs 0.05 ± 0.01) or the BCAA (0.05 ± 0.02 vs. 0.05 ± 0.01) experiments. Insulin decreased (P < 0.01) whole body phenylalanine rate of appearance (μmol·kg-1·min-1), indicating suppression of muscle proteolysis, in both the control (1.02 ± 0.04 vs 0.76 ± 0.04) and the BCAA (0.89 ± 0.07 vs 0.61 ± 0.03) experiments, but the change was not different between the two experiments (P > 0.05). In conclusion, insulin does not stimulate muscle protein synthesis in the presence of increased circulating levels of plasma BCAA alone. Insulin's suppressive effect on proteolysis is observed independently of the levels of circulating plasma BCAA.
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Affiliation(s)
- Sarah Everman
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona
| | - Christian Meyer
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona
| | - Lee Tran
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona; Mayo Clinic in Arizona, Scottsdale, Arizona; and
| | - Nyssa Hoffman
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona; Mayo Clinic in Arizona, Scottsdale, Arizona; and
| | | | | | - Christos S Katsanos
- Center for Metabolic and Vascular Biology, Arizona State University, Tempe, Arizona; Mayo Clinic in Arizona, Scottsdale, Arizona; and
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16
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Beals JW, Sukiennik RA, Nallabelli J, Emmons RS, van Vliet S, Young JR, Ulanov AV, Li Z, Paluska SA, De Lisio M, Burd NA. Anabolic sensitivity of postprandial muscle protein synthesis to the ingestion of a protein-dense food is reduced in overweight and obese young adults. Am J Clin Nutr 2016; 104:1014-1022. [PMID: 27604771 DOI: 10.3945/ajcn.116.130385] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 08/01/2016] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Excess body fat diminishes muscle protein synthesis rates in response to hyperinsulinemic-hyperaminoacidemic clamps. However, muscle protein synthetic responses after the ingestion of a protein-dense food source across a range of body mass indexes (BMIs) have not been compared. OBJECTIVE We compared the myofibrillar protein synthetic response and underlying nutrient-sensing mechanisms after the ingestion of lean pork between obese, overweight, and healthy-weight adults. DESIGN Ten healthy-weight [HW; BMI (in kg/m2): 22.7 ± 0.4], 10 overweight (OW; BMI: 27.1 ± 0.5), and 10 obese (OB; BMI: 35.9 ± 1.3) adults received primed continuous l-[ring-13C6]phenylalanine infusions. Blood and muscle biopsy samples were collected before and after the ingestion of 170 g pork (36 g protein and 3 g fat) to assess skeletal muscle anabolic signaling, amino acid transporters [large neutral and small neutral amino acid transporters (LAT1, SNAT2) and CD98], and myofibrillar protein synthesis. RESULTS At baseline, OW and OB groups showed greater relative amounts of mammalian target of rapamycin complex 1 (mTORC1) protein than the HW group. Pork ingestion increased mTORC1 phosphorylation only in the HW group (P = 0.001). LAT1 and SNAT2 protein content increased during the postprandial period in all groups (time effect, P < 0.05). Basal myofibrillar protein synthetic responses were similar between groups (P = 0.43). However, myofibrillar protein synthetic responses (0-300 min) were greater in the HW group (1.6-fold; P = 0.005) after pork ingestion than in the OW and OB groups. CONCLUSIONS There is a diminished myofibrillar protein synthetic response to the ingestion of protein-dense food in overweight and obese adults compared with healthy-weight controls. These data indicate that impaired postprandial myofibrillar protein synthetic response may be an early defect with increasing fat mass, potentially dependent on altered anabolic signals, that reduces muscle sensitivity to food ingestion. This trial was registered at clinicaltrials.gov as NCT02613767.
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Affiliation(s)
| | | | | | | | | | | | | | - Zhong Li
- Roy J Carver Biotechnology Center, and
| | - Scott A Paluska
- Department of Family Medicine, University of Illinois at Urbana-Champaign, Urbana, IL
| | - Michael De Lisio
- Division of Nutritional Sciences, Department of Kinesiology and Community Health
| | - Nicholas A Burd
- Division of Nutritional Sciences, Department of Kinesiology and Community Health,
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17
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Prolonged Exposure of Primary Human Muscle Cells to Plasma Fatty Acids Associated with Obese Phenotype Induces Persistent Suppression of Muscle Mitochondrial ATP Synthase β Subunit. PLoS One 2016; 11:e0160057. [PMID: 27532680 PMCID: PMC4988792 DOI: 10.1371/journal.pone.0160057] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 07/13/2016] [Indexed: 01/12/2023] Open
Abstract
Our previous studies show reduced abundance of the β-subunit of mitochondrial H+-ATP synthase (β-F1-ATPase) in skeletal muscle of obese individuals. The β-F1-ATPase forms the catalytic core of the ATP synthase, and it is critical for ATP production in muscle. The mechanism(s) impairing β-F1-ATPase metabolism in obesity, however, are not completely understood. First, we studied total muscle protein synthesis and the translation efficiency of β-F1-ATPase in obese (BMI, 36±1 kg/m2) and lean (BMI, 22±1 kg/m2) subjects. Both total protein synthesis (0.044±0.006 vs 0.066±0.006%·h-1) and translation efficiency of β-F1-ATPase (0.0031±0.0007 vs 0.0073±0.0004) were lower in muscle from the obese subjects when compared to the lean controls (P<0.05). We then evaluated these same responses in a primary cell culture model, and tested the specific hypothesis that circulating non-esterified fatty acids (NEFA) in obesity play a role in the responses observed in humans. The findings on total protein synthesis and translation efficiency of β-F1-ATPase in primary myotubes cultured from a lean subject, and after exposure to NEFA extracted from serum of an obese subject, were similar to those obtained in humans. Among candidate microRNAs (i.e., non-coding RNAs regulating gene expression), we identified miR-127-5p in preventing the production of β-F1-ATPase. Muscle expression of miR-127-5p negatively correlated with β-F1-ATPase protein translation efficiency in humans (r = - 0.6744; P<0.01), and could be modeled in vitro by prolonged exposure of primary myotubes derived from the lean subject to NEFA extracted from the obese subject. On the other hand, locked nucleic acid inhibitor synthesized to target miR-127-5p significantly increased β-F1-ATPase translation efficiency in myotubes (0.6±0.1 vs 1.3±0.3, in control vs exposure to 50 nM inhibitor; P<0.05). Our experiments implicate circulating NEFA in obesity in suppressing muscle protein metabolism, and establish impaired β-F1-ATPase translation as an important consequence of obesity.
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18
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Williamson DL, Dungan CM, Mahmoud AM, Mey JT, Blackburn BK, Haus JM. Aberrant REDD1-mTORC1 responses to insulin in skeletal muscle from Type 2 diabetics. Am J Physiol Regul Integr Comp Physiol 2015; 309:R855-63. [PMID: 26269521 PMCID: PMC4666944 DOI: 10.1152/ajpregu.00285.2015] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/04/2015] [Indexed: 11/22/2022]
Abstract
The objective of this study was to establish whether alterations in the REDD1-mTOR axis underlie skeletal muscle insensitivity to insulin in Type 2 diabetic (T2D), obese individuals. Vastus lateralis muscle biopsies were obtained from lean, control and obese, T2D subjects under basal and after a 2-h hyperinsulinemic (40 mU·m(-2)·min(-1))-euglycemic (5 mM) clamp. Muscle lysates were examined for total REDD1, and phosphorylated Akt, S6 kinase 1 (S6K1), 4E-BP1, ERK1/2, and MEK1/2 via Western blot analysis. Under basal conditions [(-) insulin], T2D muscle exhibited higher S6K1 and ERK1/2 and lower 4E-BP1 phosphorylation (P < 0.05), as well as elevations in blood cortisol, glucose, insulin, glycosylated hemoglobin (P < 0.05) vs. lean controls. Following insulin infusion, whole body glucose disposal rates (GDR; mg/kg/min) were lower (P < 0.05) in the T2D vs. the control group. The basal-to-insulin percent change in REDD1 expression was higher (P < 0.05) in muscle from the T2D vs. the control group. Whereas, the basal-to-insulin percent change in muscle Akt, S6K1, ERK1/2, and MEK1/2 phosphorylation was significantly lower (P < 0.05) in the T2D vs. the control group. Findings from this study propose a REDD1-regulated mechanism in T2D skeletal muscle that may contribute to whole body insulin resistance and may be a target to improve insulin action in insulin-resistant individuals.
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Affiliation(s)
- David L Williamson
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York; and
| | - Cory M Dungan
- Department of Exercise and Nutrition Sciences, School of Public Health and Health Professions, University at Buffalo, Buffalo, New York; and
| | - Abeer M Mahmoud
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois
| | - Jacob T Mey
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois
| | - Brian K Blackburn
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois
| | - Jacob M Haus
- Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, Illinois
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