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Montenegro CF, Skiles C, Kuszmaul DJ, Gouw A, Minchev K, Chambers TL, Raue U, Trappe TA, Trappe S. Fast and slow myofiber nuclei, satellite cells, and size distribution with lifelong endurance exercise in men and women. Physiol Rep 2024; 12:e16052. [PMID: 38987200 PMCID: PMC11236482 DOI: 10.14814/phy2.16052] [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: 03/01/2024] [Revised: 05/03/2024] [Accepted: 05/03/2024] [Indexed: 07/12/2024] Open
Abstract
We previously observed lifelong endurance exercise (LLE) influenced quadriceps whole-muscle and myofiber size in a fiber-type and sex-specific manner. The current follow-up exploratory investigation examined myofiber size regulators and myofiber size distribution in vastus lateralis biopsies from these same LLE men (n = 21, 74 ± 1 years) and women (n = 7, 72 ± 2 years) as well as old, healthy nonexercisers (OH; men: n = 10, 75 ± 1 years; women: n = 10, 75 ± 1 years) and young exercisers (YE; men: n = 10, 25 ± 1 years; women: n = 10, 25 ± 1 years). LLE exercised ~5 days/week, ~7 h/week for the previous 52 ± 1 years. Slow (myosin heavy chain (MHC) I) and fast (MHC IIa) myofiber nuclei/fiber, myonuclear domain, satellite cells/fiber, and satellite cell density were not influenced (p > 0.05) by LLE in men and women. The aging groups had ~50%-60% higher proportion of large (>7000 μm2) and small (<3000 μm2) myofibers (OH; men: 44%, women: 48%, LLE; men: 42%, women: 42%, YE; men: 27%, women: 29%). LLE men had triple the proportion of large slow fibers (LLE: 21%, YE: 7%, OH: 7%), while LLE women had more small slow fibers (LLE: 15%, YE: 8%, OH: 9%). LLE reduced by ~50% the proportion of small fast (MHC II containing) fibers in the aging men (OH: 14%, LLE: 7%) and women (OH: 35%, LLE: 18%). These data, coupled with previous findings, suggest that myonuclei and satellite cell content are uninfluenced by lifelong endurance exercise in men ~60-90 years, and this now also extends to septuagenarian lifelong endurance exercise women. Additionally, lifelong endurance exercise appears to influence the relative abundance of small and large myofibers (fast and slow) differently between men and women.
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Affiliation(s)
| | - Chad Skiles
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Dillon J Kuszmaul
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Aaron Gouw
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Kiril Minchev
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Toby L Chambers
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Ulrika Raue
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Todd A Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana, USA
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Jorgenson KW, Hibbert JE, Sayed RKA, Lange AN, Godwin JS, Mesquita PHC, Ruple BA, McIntosh MC, Kavazis AN, Roberts MD, Hornberger TA. A novel imaging method (FIM-ID) reveals that myofibrillogenesis plays a major role in the mechanically induced growth of skeletal muscle. eLife 2024; 12:RP92674. [PMID: 38466320 PMCID: PMC10928493 DOI: 10.7554/elife.92674] [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] [Indexed: 03/12/2024] Open
Abstract
An increase in mechanical loading, such as that which occurs during resistance exercise, induces radial growth of muscle fibers (i.e. an increase in cross-sectional area). Muscle fibers are largely composed of myofibrils, but whether radial growth is mediated by an increase in the size of the myofibrils (i.e. myofibril hypertrophy) and/or the number of myofibrils (i.e. myofibrillogenesis) is not known. Electron microscopy (EM) can provide images with the level of resolution that is needed to address this question, but the acquisition and subsequent analysis of EM images is a time- and cost-intensive process. To overcome this, we developed a novel method for visualizing myofibrils with a standard fluorescence microscope (fluorescence imaging of myofibrils with image deconvolution [FIM-ID]). Images from FIM-ID have a high degree of resolution and contrast, and these properties enabled us to develop pipelines for automated measurements of myofibril size and number. After extensively validating the automated measurements, we used both mouse and human models of increased mechanical loading to discover that the radial growth of muscle fibers is largely mediated by myofibrillogenesis. Collectively, the outcomes of this study offer insight into a fundamentally important topic in the field of muscle growth and provide future investigators with a time- and cost-effective means to study it.
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Affiliation(s)
- Kent W Jorgenson
- School of Veterinary Medicine and the Department of Comparative Biosciences, University of Wisconsin-MadisonMadisonUnited States
| | - Jamie E Hibbert
- School of Veterinary Medicine and the Department of Comparative Biosciences, University of Wisconsin-MadisonMadisonUnited States
| | - Ramy KA Sayed
- School of Veterinary Medicine and the Department of Comparative Biosciences, University of Wisconsin-MadisonMadisonUnited States
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Sohag UniversitySohagEgypt
| | - Anthony N Lange
- School of Veterinary Medicine and the Department of Comparative Biosciences, University of Wisconsin-MadisonMadisonUnited States
| | | | | | | | | | | | | | - Troy A Hornberger
- School of Veterinary Medicine and the Department of Comparative Biosciences, University of Wisconsin-MadisonMadisonUnited States
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Fu P, Zhu R, Gao W, Gong L. Effects of resistance training on alleviating hypoxia-induced muscle atrophy: Focus on acetylation of FoxO1. J Cell Mol Med 2024; 28:e18096. [PMID: 38149787 PMCID: PMC10844693 DOI: 10.1111/jcmm.18096] [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: 09/13/2023] [Revised: 11/28/2023] [Accepted: 12/19/2023] [Indexed: 12/28/2023] Open
Abstract
This study aims to explore the role of FoxO1 and its acetylation in the alleviation of hypoxia-induced muscle atrophy by resistance training. Forty male Sprague-Dawley rats were randomly divided into four groups: normoxic control group (C), normoxic resistance training group (R), hypoxic control group (H) and hypoxic resistance training group (HR). Rats in R and HR groups were trained on an incremental weight-bearing ladder every other day, while those in H and HR groups were kept in an environment containing 12.4% O2 . After 4 weeks, muscles were collected for analysis. Differentiated L6 myoblasts were analysed in vitro after hypoxia exposure and plasmids transfection (alteration in FoxO1 acetylation). The lean body mass loss, wet weight and fibre cross-sectional area of extensor digitorum longus of rats were decreased after 4 weeks hypoxia, and the adverse reactions above was reversed by resistance training. At the same time, the increase in hypoxia-induced autophagy was suppressed, which was accompanied by a decrease in the expression of nuclear FoxO1 and cytoplasmic Ac-FoxO1 by resistance training. The L6 myotube diameter increased and the expression of autophagic proteins were inhibited under hypoxia via intervening by FoxO1 deacetylation. Overall, resistance training alleviates hypoxia-induced muscle atrophy by inhibiting nuclear FoxO1 and cytoplasmic Ac-FoxO1-mediated autophagy.
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Affiliation(s)
- Pengyu Fu
- Key Laboratory of Physical Fitness and Exercise, Ministry of EducationBeijing Sport UniversityBeijingChina
- Department of Physical EducationNorthwestern Polytechnical UniversityXi'anChina
| | - Rongxin Zhu
- Shanghai Research Institute of Sports ScienceShanghaiChina
| | - Weiyang Gao
- School of Languages and Cultural Communication, English DepartmentXi’an Mingde Institute of TechnologyXi’anChina
| | - Lijing Gong
- Key Laboratory of Physical Fitness and Exercise, Ministry of EducationBeijing Sport UniversityBeijingChina
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Sayed RKA, Hibbert JE, Jorgenson KW, Hornberger TA. The Structural Adaptations That Mediate Disuse-Induced Atrophy of Skeletal Muscle. Cells 2023; 12:2811. [PMID: 38132132 PMCID: PMC10741885 DOI: 10.3390/cells12242811] [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: 11/11/2023] [Revised: 12/07/2023] [Accepted: 12/09/2023] [Indexed: 12/23/2023] Open
Abstract
The maintenance of skeletal muscle mass plays a fundamental role in health and issues associated with quality of life. Mechanical signals are one of the most potent regulators of muscle mass, with a decrease in mechanical loading leading to a decrease in muscle mass. This concept has been supported by a plethora of human- and animal-based studies over the past 100 years and has resulted in the commonly used term of 'disuse atrophy'. These same studies have also provided a great deal of insight into the structural adaptations that mediate disuse-induced atrophy. For instance, disuse results in radial atrophy of fascicles, and this is driven, at least in part, by radial atrophy of the muscle fibers. However, the ultrastructural adaptations that mediate these changes remain far from defined. Indeed, even the most basic questions, such as whether the radial atrophy of muscle fibers is driven by the radial atrophy of myofibrils and/or myofibril hypoplasia, have yet to be answered. In this review, we thoroughly summarize what is known about the macroscopic, microscopic, and ultrastructural adaptations that mediated disuse-induced atrophy and highlight some of the major gaps in knowledge that need to be filled.
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Affiliation(s)
- Ramy K. A. Sayed
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
- Department of Anatomy and Embryology, Faculty of Veterinary Medicine, Sohag University, Sohag 82524, Egypt
| | - Jamie E. Hibbert
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Kent W. Jorgenson
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
| | - Troy A. Hornberger
- Department of Comparative Biosciences, University of Wisconsin—Madison, Madison, WI 53706, USA; (R.K.A.S.); (J.E.H.); (K.W.J.)
- School of Veterinary Medicine, University of Wisconsin—Madison, Madison, WI 53706, USA
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Rossios C, Bashir T, Achison M, Adamson S, Akpan A, Aspray T, Avenell A, Band MM, Burton LA, Cvoro V, Donnan PT, Duncan GW, George J, Gordon AL, Gregson CL, Hapca A, Hume C, Jackson TA, Kerr S, Kilgour A, Masud T, McKenzie A, McKenzie E, Patel H, Pilvinyte K, Roberts HC, Sayer AA, Smith KT, Soiza RL, Steves CJ, Struthers AD, Tiwari D, Whitney J, Witham MD, Kemp PR. ACE I/D genotype associates with strength in sarcopenic men but not with response to ACE inhibitor therapy in older adults with sarcopenia: Results from the LACE trial. PLoS One 2023; 18:e0292402. [PMID: 37862321 PMCID: PMC10588903 DOI: 10.1371/journal.pone.0292402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023] Open
Abstract
BACKGROUND Angiotensin II (AII), has been suggested to promote muscle loss. Reducing AII synthesis, by inhibiting angiotensin converting enzyme (ACE) activity has been proposed as a method to inhibit muscle loss. The LACE clinical trial was designed to determine whether ACE inhibition would reduce further muscle loss in individuals with sarcopenia but suffered from low recruitment and returned a negative result. Polymorphic variation in the ACE promoter (I/D alleles) has been associated with differences in ACE activity and muscle physiology in a range of clinical conditions. This aim of this analysis was to determine whether I/D polymorphic variation is associated with muscle mass, strength, in sarcopenia or contributed to the lack of response to treatment in the LACE study. METHODS Sarcopenic individuals were recruited into a 2x2 factorial multicentre double-blind study of the effects of perindopril and/or leucine versus placebo on physical performance and muscle mass. DNA extracted from blood samples (n = 130 72 women and 58 men) was genotyped by PCR for the ACE I/D polymorphism. Genotypes were then compared with body composition measured by DXA, hand grip and quadriceps strength before and after 12 months' treatment with leucine and/or perindopril in a cross-sectional analysis of the influence of genotype on these variables. RESULTS Allele frequencies for the normal UK population were extracted from 13 previous studies (I = 0.473, D = 0.527). In the LACE cohort the D allele was over-represented (I = 0.412, D = 0.588, p = 0.046). This over-representation was present in men (I = 0.353, D = 0.647, p = 0.010) but not women (I = 0.458, D = 0.532, p = 0.708). In men but not women, individuals with the I allele had greater leg strength (II/ID = 18.00 kg (14.50, 21.60) vs DD = 13.20 kg (10.50, 15.90), p = 0.028). Over the 12 months individuals with the DD genotype increased in quadriceps strength but those with the II or ID genotype did not. Perindopril did not increase muscle strength or mass in any polymorphism group relative to placebo. CONCLUSION Our results suggest that although ACE genotype was not associated with response to ACE inhibitor therapy in the LACE trial population, sarcopenic men with the ACE DD genotype may be weaker than those with the ACE I/D or II genotype.
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Affiliation(s)
- Christos Rossios
- Cardiovascular and Respiratory Interface Section, National Heart and Lung Institute, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Tufail Bashir
- Cardiovascular and Respiratory Interface Section, National Heart and Lung Institute, Imperial College London, South Kensington Campus, London, United Kingdom
| | - Marcus Achison
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Simon Adamson
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Asangaedem Akpan
- University of Liverpool, Liverpool University Hospitals NHS FT Trust, Clinical Research Network Northwest Coast, Liverpool, United Kingdom
| | - Terry Aspray
- AGE Research Group, NIHR Newcastle Biomedical Research Centre, Translational Clinical Research Institute, Newcastle University, Cumbria Northumberland Tyne and Wear NHS Foundation Trust and Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, United Kingdom
| | - Alison Avenell
- Health Services Research Unit, University of Aberdeen, Aberdeen, United Kingdom
| | - Margaret M. Band
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Louise A. Burton
- Medicine for the Elderly, NHS Tayside, Dundee, United Kingdom
- Ageing and Health, University of Dundee, Dundee, United Kingdom
| | - Vera Cvoro
- Victoria Hospital, Kirkcaldy, United Kingdom
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Peter T. Donnan
- Division of Population Health and Genomics, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Gordon W. Duncan
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Medicine for the Elderly, NHS Lothian, Edinburgh, United Kingdom
| | - Jacob George
- Dept Clinical Pharmacology, Division of Molecular & Clinical Medicine, University of Dundee Medical School, Ninewells Hospital, Dundee, United Kingdom
| | - Adam L. Gordon
- Unit of Injury, Inflammation and Recovery, School of Medicine, University of Nottingham, Nottingham, United Kingdom
- NIHR Nottingham Biomedical Research Centre, Department of Medicine for the Elderly, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, United Kingdom
| | - Celia L. Gregson
- Musculoskeletal Research Unit, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Older Person’s Unit, Royal United Hospital NHS Foundation Trust Bath, Bath, United Kingdom
| | - Adrian Hapca
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Cheryl Hume
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Thomas A. Jackson
- Institute of Inflammation and Ageing, University of Birmingham, Birmingham, United Kingdom
| | - Simon Kerr
- Department of Older People’s Medicine, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Alixe Kilgour
- Medicine for the Elderly, NHS Lothian, Edinburgh, United Kingdom
- Ageing and Health Research Group, Usher Institute, University of Edinburgh, Edinburgh, United Kingdom
| | - Tahir Masud
- Clinical Gerontology Research Unit, Nottingham University Hospitals NHS Trust, City Hospital Campus, Nottingham, United Kingdom
| | - Andrew McKenzie
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Emma McKenzie
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Harnish Patel
- NIHR Biomedical Research Centre, University of Southampton and University Hospital Southampton NHSFT, Southampton, Hampshire, United Kingdom
| | - Kristina Pilvinyte
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Helen C. Roberts
- Academic Geriatric Medicine, University of Southampton, Mailpoint 807 Southampton General Hospital, Southampton, United Kingdom
| | - Avan A. Sayer
- AGE Research Group, NIHR Newcastle Biomedical Research Centre, Translational Clinical Research Institute, Newcastle University, Cumbria Northumberland Tyne and Wear NHS Foundation Trust and Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, United Kingdom
| | - Karen T. Smith
- Tayside Clinical Trials Unit (TCTU), Tayside Medical Science Centre (TASC), University of Dundee, Ninewells Hospital & Medical School, Dundee, United Kingdom
| | - Roy L. Soiza
- Ageing & Clinical Experimental Research (ACER) Group, University of Aberdeen, Aberdeen, United Kingdom
| | - Claire J. Steves
- Department of Twin Research and Genetic Epidemiology, King’s College London & Department of Clinical Gerontology, King’s College Hospital, London, United Kingdom
| | - Allan D. Struthers
- Dept Clinical Pharmacology, Division of Molecular & Clinical Medicine, University of Dundee Medical School, Ninewells Hospital, Dundee, United Kingdom
| | - Divya Tiwari
- Bournemouth University and Royal Bournemouth Hospital, Bournemouth, United Kingdom
| | - Julie Whitney
- School of Population Health & Environmental Sciences, King’s College London and King’s College Hospital, London, United Kingdom
| | - Miles D. Witham
- AGE Research Group, NIHR Newcastle Biomedical Research Centre, Translational Clinical Research Institute, Newcastle University, Cumbria Northumberland Tyne and Wear NHS Foundation Trust and Newcastle upon Tyne Hospitals NHS Trust, Newcastle upon Tyne, United Kingdom
| | - Paul R. Kemp
- Cardiovascular and Respiratory Interface Section, National Heart and Lung Institute, Imperial College London, South Kensington Campus, London, United Kingdom
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Chambers TL, Stroh AM, Chavez C, Brandt AR, Claiborne A, Fountain WA, Gries KJ, Jones AM, Kuszmaul DJ, Lee GA, Lester BE, Lynch CE, Minchev K, Montenegro CF, Naruse M, Raue U, Trappe TA, Trappe S. Multitissue responses to exercise: a MoTrPAC feasibility study. J Appl Physiol (1985) 2023; 135:302-315. [PMID: 37318985 PMCID: PMC10393343 DOI: 10.1152/japplphysiol.00210.2023] [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: 04/03/2023] [Revised: 06/05/2023] [Accepted: 06/12/2023] [Indexed: 06/17/2023] Open
Abstract
We assessed the feasibility of the Molecular Transducers of Physical Activity Consortium (MoTrPAC) human adult clinical exercise protocols, while also documenting select cardiovascular, metabolic, and molecular responses to these protocols. After phenotyping and familiarization sessions, 20 subjects (25 ± 2 yr, 12 M, 8 W) completed an endurance exercise bout (n = 8, 40 min cycling at 70% V̇o2max), a resistance exercise bout (n = 6, ∼45 min, 3 sets of ∼10 repetition maximum, 8 exercises), or a resting control period (n = 6, 40 min rest). Blood samples were taken before, during, and after (10 min, 2 h, and 3.5 h) exercise or rest for levels of catecholamines, cortisol, glucagon, insulin, glucose, free fatty acids, and lactate. Heart rate was recorded throughout exercise (or rest). Skeletal muscle (vastus lateralis) and adipose (periumbilical) biopsies were taken before and ∼4 h following exercise or rest for mRNA levels of genes related to energy metabolism, growth, angiogenesis, and circadian processes. Coordination of the timing of procedural components (e.g., local anesthetic delivery, biopsy incisions, tumescent delivery, intravenous line flushes, sample collection and processing, exercise transitions, and team dynamics) was reasonable to orchestrate while considering subject burden and scientific objectives. The cardiovascular and metabolic alterations reflected a dynamic and unique response to endurance and resistance exercise, whereas skeletal muscle was transcriptionally more responsive than adipose 4 h postexercise. In summary, the current report provides the first evidence of protocol execution and feasibility of key components of the MoTrPAC human adult clinical exercise protocols. Scientists should consider designing exercise studies in various populations to interface with the MoTrPAC protocols and DataHub.NEW & NOTEWORTHY This study highlights the feasibility of key aspects of the MoTrPAC adult human clinical protocols. This initial preview of what can be expected from acute exercise trial data from MoTrPAC provides an impetus for scientists to design exercise studies to interlace with the rich phenotypic and -omics data that will populate the MoTrPAC DataHub at the completion of the parent protocol.
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Affiliation(s)
- Toby L Chambers
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Andrew M Stroh
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Clarisa Chavez
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Anna R Brandt
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Alex Claiborne
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - William A Fountain
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Kevin J Gries
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Andrew M Jones
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Dillon J Kuszmaul
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Gary A Lee
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Bridget E Lester
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Colleen E Lynch
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Kiril Minchev
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | | | - Masatoshi Naruse
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Ulrika Raue
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Todd A Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
| | - Scott Trappe
- Human Performance Laboratory, Ball State University, Muncie, Indiana, United States
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7
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Naruse M, Vincenty CS, Konopka AR, Trappe SW, Harber MP, Trappe TA. Cycle exercise training and muscle mass: A preliminary investigation of 17 lower limb muscles in older men. Physiol Rep 2023; 11:e15781. [PMID: 37606179 PMCID: PMC10442866 DOI: 10.14814/phy2.15781] [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: 06/19/2023] [Revised: 07/14/2023] [Accepted: 07/17/2023] [Indexed: 08/23/2023] Open
Abstract
Cycling exercise in older individuals is beneficial for the cardiovascular system and quadriceps muscles, including partially reversing the age-related loss of quadriceps muscle mass. However, the effect of cycling exercise on the numerous other lower limb muscles is unknown. Six older men (74 ± 8 years) underwent MRI before and after 12-weeks of progressive aerobic cycle exercise training (3-4 days/week, 60-180 min/week, 60%-80% heart rate reserve, VO2 max: +13%) for upper (rectus femoris, vastii, adductor longus, adductor magnus, gracilis, sartorius, biceps femoris long head, biceps femoris short head, semimembranosus, semitendinosus) and lower (anterior tibial, posterior tibialis, peroneals, flexor digitorum longus, lateral gastrocnemius, medial gastrocnemius, soleus) leg muscle volumes. In the upper leg, cycle exercise training induced hypertrophy (p ≤ 0.05) in the vastii (+7%) and sartorius (+6%), with a trend to increase biceps femoris short head (+5%, p = 0.1). Additionally, there was a trend to decrease muscle volume in the adductor longus (-6%, p = 0.1) and biceps femoris long head (-5%, p = 0.09). In the lower leg, all 7 muscle volumes assessed were unaltered pre- to post-training (-2% to -3%, p > 0.05). This new evidence related to cycle exercise training in older individuals clarifies the specific upper leg muscles that are highly impacted, while revealing all the lower leg muscles do not appear responsive, in the context of muscle mass and sarcopenia. This study provides information for exercise program development in older individuals, suggesting other specific exercises are needed for the rectus femoris and adductors, certain hamstrings, and the anterior and posterior lower leg muscles to augment the beneficial effects of cycling exercise for older adults.
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Affiliation(s)
- Masatoshi Naruse
- Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | | | - Adam R. Konopka
- Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | - Scott W. Trappe
- Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
| | | | - Todd A. Trappe
- Human Performance LaboratoryBall State UniversityMuncieIndianaUSA
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Joyner MJ, Wiggins CC, Baker SE, Klassen SA, Senefeld JW. Exercise and Experiments of Nature. Compr Physiol 2023; 13:4879-4907. [PMID: 37358508 PMCID: PMC10853940 DOI: 10.1002/cphy.c220027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
In this article, we highlight the contributions of passive experiments that address important exercise-related questions in integrative physiology and medicine. Passive experiments differ from active experiments in that passive experiments involve limited or no active intervention to generate observations and test hypotheses. Experiments of nature and natural experiments are two types of passive experiments. Experiments of nature include research participants with rare genetic or acquired conditions that facilitate exploration of specific physiological mechanisms. In this way, experiments of nature are parallel to classical "knockout" animal models among human research participants. Natural experiments are gleaned from data sets that allow population-based questions to be addressed. An advantage of both types of passive experiments is that more extreme and/or prolonged exposures to physiological and behavioral stimuli are possible in humans. In this article, we discuss a number of key passive experiments that have generated foundational medical knowledge or mechanistic physiological insights related to exercise. Both natural experiments and experiments of nature will be essential to generate and test hypotheses about the limits of human adaptability to stressors like exercise. © 2023 American Physiological Society. Compr Physiol 13:4879-4907, 2023.
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Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Chad C Wiggins
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Sarah E Baker
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
| | - Stephen A Klassen
- Department of Kinesiology, Brock University, St. Catharines, Ontario, Canada
| | - Jonathon W Senefeld
- Department of Anesthesiology & Perioperative Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Physiology & Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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9
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Van Vossel K, Hardeel J, Van de Casteele F, Van der Stede T, Weyns A, Boone J, Blemker SS, Lievens E, Derave W. Can muscle typology explain the inter-individual variability in resistance training adaptations? J Physiol 2023; 601:2307-2327. [PMID: 37038845 DOI: 10.1113/jp284442] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/03/2023] [Indexed: 04/12/2023] Open
Abstract
Considerable inter-individual heterogeneity exists in the muscular adaptations to resistance training. It has been proposed that fast-twitch fibres are more sensitive to hypertrophic stimuli and thus that variation in muscle fibre type composition is a contributing factor to the magnitude of training response. This study investigated if the inter-individual variability in resistance training adaptations is determined by muscle typology and if the most appropriate weekly training frequency depends on muscle typology. In strength-training novices, 11 slow (ST) and 10 fast typology (FT) individuals were selected by measuring muscle carnosine with proton magnetic resonance spectroscopy. Participants trained both upper arm and leg muscles to failure at 60% of one-repetition maximum (1RM) for 10 weeks, whereby one arm and leg trained 3×/week and the contralateral arm and leg 2×/week. Muscle volume (MRI-based 3D segmentation), maximal dynamic strength (1RM) and fibre type-specific cross-sectional area (vastus lateralis biopsies) were evaluated. The training response for total muscle volume (+3 to +14%), fibre size (-19 to +22%) and strength (+17 to +47%) showed considerable inter-individual variability, but these could not be attributed to differences in muscle typology. However, ST individuals performed a significantly higher training volume to gain these similar adaptations than FT individuals. The limb that trained 3×/week had generally more pronounced hypertrophy than the limb that trained 2×/week, and there was no interaction with muscle typology. In conclusion, muscle typology cannot explain the high variability in resistance training adaptations when training is performed to failure at 60% of 1RM. KEY POINTS: This study investigated the influence of muscle typology (muscle fibre type composition) on the variability in resistance training adaptations and on its role in the individualization of resistance training frequency. We demonstrate that an individual's muscle typology cannot explain the inter-individual variability in resistance training-induced increases in muscle volume, maximal dynamic strength and fibre cross-sectional area when repetitions are performed to failure. Importantly, slow typology individuals performed a significantly higher training volume to obtain similar adaptations compared to fast typology individuals. Muscle typology does not determine the most appropriate resistance training frequency. However, regardless of muscle typology, an additional weekly training (3×/week vs. 2×/week) increases muscle hypertrophy but not maximal dynamic strength. These findings expand on our understanding of the underlying mechanisms for the large inter-individual variability in resistance training adaptations.
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Affiliation(s)
- Kim Van Vossel
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Julie Hardeel
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | | | - Thibaux Van der Stede
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Anneleen Weyns
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Jan Boone
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Silvia Salinas Blemker
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA, USA
- Springbok Analytics, Charlottesville, VA, USA
| | - Eline Lievens
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
| | - Wim Derave
- Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium
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10
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Serum Metabolites Associated with Muscle Hypertrophy after 8 Weeks of High- and Low-Load Resistance Training. Metabolites 2023; 13:metabo13030335. [PMID: 36984775 PMCID: PMC10058868 DOI: 10.3390/metabo13030335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/13/2023] [Accepted: 02/18/2023] [Indexed: 02/26/2023] Open
Abstract
The mechanisms responsible for the similar muscle growth attained with high- and low-load resistance training (RT) have not yet been fully elucidated. One mechanism is related to the mechanical stimulus and the level of motor unit recruitment; another mechanism is related to the metabolic response. We investigated the electromyographic signal amplitude (sEMG) and the general metabolic response to high-load RT (HL) and low-load resistance training (LL). We measured muscle thickness by ultrasound, sEMG amplitude by electromyography, and analysis of metabolites expressed through metabolomics. No differences were observed between the HL and LL groups for metabolic response and muscle thickness. A greater amplitude of sEMG was observed in the HL group. In addition, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle in the HL group and levels of the metabolites carnitine, creatine, 3-hydroxyisovalerate, phenylalanine, asparagine, creatine phosphate, and methionine. In the LL group, a correlation was observed between changes in muscle thickness of the vastus lateralis muscle and levels of the metabolites acetoacetate, creatine phosphate, and oxypurinol. These correlations seem to be related to the characteristics of activated muscle fibers, the metabolic demand of the training protocols used, and the process of protein synthesis.
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11
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Dombrecht D, Van Daele U, Van Asbroeck B, Schieffelers D, Guns PJ, Gebruers N, Meirte J, van Breda E. Molecular mechanisms of post-burn muscle wasting and the therapeutic potential of physical exercise. J Cachexia Sarcopenia Muscle 2023; 14:758-770. [PMID: 36760077 PMCID: PMC10067483 DOI: 10.1002/jcsm.13188] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 01/03/2023] [Accepted: 01/16/2023] [Indexed: 02/11/2023] Open
Abstract
After a severe burn injury, a systemic stress response activates metabolic and inflammatory derangements that, among other, leads to muscle mass loss (muscle wasting). These negative effects on skeletal muscle continue for several months or years and are aggravated by short-term and long-term disuse. The dynamic balance between muscle protein synthesis and muscle protein breakdown (proteolysis) is regulated by complex signalling pathways that leads to an overall negative protein balance in skeletal muscle after a burn injury. Research concerning these molecular mechanisms is still scarce and inconclusive, understanding of which, if any, molecular mechanisms contribute to muscle wasting is of fundamental importance in designing of therapeutic interventions for burn patients as well. This review not only summarizes our present knowledge of the molecular mechanisms that underpin muscle protein balance but also summarizes the effects of exercise on muscle wasting post-burn as promising strategy to counteract the detrimental effects on skeletal muscle. Future research focusing on the pathways causing post-burn muscle wasting and the different effects of exercise on them is needed to confirm this hypothesis and to lay the foundation of therapeutic strategies.
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Affiliation(s)
- Dorien Dombrecht
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium
| | - Ulrike Van Daele
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium.,Oscare, Organisation for Burns, Scar After-Care and Research, Antwerp, Belgium
| | - Birgit Van Asbroeck
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium
| | - David Schieffelers
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium
| | - Pieter-Jan Guns
- Laboratory of Physiopharmacology, University of Antwerp, Antwerp, Belgium
| | - Nick Gebruers
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium.,Multidisciplinary Edema Clinic, Antwerp University Hospital, Edegem, Belgium
| | - Jill Meirte
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium.,Oscare, Organisation for Burns, Scar After-Care and Research, Antwerp, Belgium
| | - Eric van Breda
- Department of Rehabilitation Sciences & Physiotherapy, Research group MOVANT, Multidisciplinary Metabolic Research Unit (M2RUN), University of Antwerp, Antwerp, Belgium
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12
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Marume K, Mugele H, Ueno R, Amin SB, Lesmana HS, Possnig C, Hansen AB, Simpson LL, Lawley JS. The impact of leg position on muscle blood flow and oxygenation during low-intensity rhythmic plantarflexion exercise. Eur J Appl Physiol 2023; 123:1091-1099. [PMID: 36645478 PMCID: PMC10119266 DOI: 10.1007/s00421-022-05117-9] [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: 05/28/2022] [Accepted: 12/12/2022] [Indexed: 01/17/2023]
Abstract
PURPOSE Resistance training (RT) is an effective countermeasure to combat physical deconditioning whereby localized hypoxia within the limb increases metabolic stress eliciting muscle adaptation. The current study sought to examine the influence of gravity on muscle oxygenation (SmO2) alongside vascular hemodynamic responses. METHODS In twelve young healthy adults, an ischemic occlusion test and seven minutes of low-intensity rhythmic plantarflexion exercise were used alongside superficial femoral blood flow and calf near-infrared spectroscopy to assess the microvascular vasodilator response, conduit artery flow-mediated dilation, exercise-induced hyperemia, and SmO2 with the leg positioned above or below the heart in a randomized order. RESULTS The microvascular vasodilator response, assessed by peak blood flow (798 ± 231 mL/min vs. 1348 ± 290 mL/min; p < 0.001) and reperfusion slope 10 s of SmO2 after cuff deflation (0.75 ± 0.45%.s-1 vs.2.40 ± 0.94%.s-1; p < 0.001), was attenuated with the leg above the heart. This caused a blunted dilatation of the superficial femoral artery (3.0 ± 2.4% vs. 5.2 ± 2.1%; p = 0.008). Meanwhile, blood flow area under the curve was comparable (above the heart: 445 ± 147 mL vs. below the heart: 474 ± 118 mL; p = 0.55) in both leg positions. During rhythmic exercise, the increase in femoral blood flow was lower in the leg up position (above the heart: 201 ± 94% vs. below the heart: 292 ± 114%; p = 0.001) and contributed to a lower SmO2 (above the heart: 41 ± 18% vs. below the heart 67 ± 5%; p < 0.001). CONCLUSION Positioning the leg above the heart results in attenuated peak vascular dilator response and exercise-induced hyperemia that coincided with a lower SmO2 during low-intensity plantarflexion exercise.
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Affiliation(s)
- Kyohei Marume
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.
| | - Hendrik Mugele
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Ryo Ueno
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Sachin B Amin
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | | | - Carmen Possnig
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Alexander B Hansen
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Lydia L Simpson
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria
| | - Justin S Lawley
- Department of Sport Science, University of Innsbruck, Innsbruck, Austria.
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.
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13
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Abstract
Skeletal muscle mass is a very plastic characteristic of skeletal muscle and is regulated by signaling pathways that control the balance between anabolic and catabolic processes. The serine/threonine kinase mechanistic/mammalian target of rapamycin (mTOR) has been shown to be critically important in the regulation of skeletal muscle mass through its regulation of protein synthesis and degradation pathways. In this commentary, recent advances in the understanding of the role of mTORC1 in the regulation of muscle mass under conditions that induce hypertrophy and atrophy will be highlighted.
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Affiliation(s)
- Sue C Bodine
- Department of Internal Medicine, Division of Endocrinology and Metabolism, University of Iowa Carver College of Medicine, 200 Hawkins Drive, Iowa City, IA 52242, USA
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14
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Shirai T, Kitaoka Y, Uemichi K, Tokinoya K, Takeda K, Takemasa T. Effects of lactate administration on hypertrophy and mTOR signaling activation in mouse skeletal muscle. Physiol Rep 2022; 10:e15436. [PMID: 35993446 PMCID: PMC9393907 DOI: 10.14814/phy2.15436] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 05/01/2022] [Accepted: 05/16/2022] [Indexed: 04/12/2023] Open
Abstract
Lactate is a metabolic product of glycolysis and has recently been shown to act as a signaling molecule that induces adaptations in oxidative metabolism. In this study, we investigated whether lactate administration enhanced muscle hypertrophy and protein synthesis responses during resistance exercise in animal models. We used male ICR mice (7-8 weeks old) were used for chronic (mechanical overload induced by synergist ablation: [OL]) and acute (high-intensity muscle contraction by electrical stimulation: [ES]) resistance exercise models. The animals were intraperitoneally administrated a single dose of sodium lactate (1 g/kg of body weight) in the ES study, and once a day for 14 consecutive days in the OL study. Two weeks of mechanical overload increased plantaris muscle wet weight (main effect of OL: p < 0.05) and fiber cross-sectional area (main effect of OL: p < 0.05), but those were not affected by lactate administration. Following the acute resistance exercise by ES, protein synthesis and phosphorylation of p70 S6 kinase and ribosomal protein S6, which are downstream molecules in the anabolic signaling cascade, were increased (main effect of ES: p < 0.05), but lactate administration had no effect. This study demonstrated that exogenous lactate administration has little effect on the muscle hypertrophic response during resistance exercise using acute ES and chronic OL models. Our results do not support the hypothesis that elevated blood lactate concentration induces protein synthesis responses in skeletal muscle.
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Affiliation(s)
- Takanaga Shirai
- Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaIbarakiJapan
- Research Fellow of Japan Society for Promotion ScienceChiyoda‐kuTokyoJapan
| | - Yu Kitaoka
- Department of Human SciencesKanagawa UniversityYokohama‐shiKanagawaJapan
| | - Kazuki Uemichi
- Graduate School of Comprehensive Human SciencesUniversity of TsukubaTsukubaIbarakiJapan
| | - Katsuyuki Tokinoya
- Research Fellow of Japan Society for Promotion ScienceChiyoda‐kuTokyoJapan
- Division of Clinical Medicine, Faculty of MedicineUniversity of TsukubaTsukubaIbarakiJapan
- Department of Health Promotion SciencesGraduate School of Human Health SciencesTokyo Metropolitan UniversityHachiojiTokyoJapan
| | - Kohei Takeda
- School of Political Science and EconomicsMeiji UniversitySuginami‐kuTokyoJapan
| | - Tohru Takemasa
- Faculty of Health and Sport SciencesUniversity of TsukubaTsukubaIbarakiJapan
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15
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Lack of muscle stem cell proliferation and myocellular hypertrophy in sIBM patients following blood-flow restricted resistance training. Neuromuscul Disord 2022; 32:493-502. [DOI: 10.1016/j.nmd.2022.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 02/22/2022] [Accepted: 04/22/2022] [Indexed: 11/24/2022]
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16
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Minari ALA, Thomatieli-Santos RV. From skeletal muscle damage and regeneration to the hypertrophy induced by exercise: What is the role of different macrophages subsets? Am J Physiol Regul Integr Comp Physiol 2021; 322:R41-R54. [PMID: 34786967 DOI: 10.1152/ajpregu.00038.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Macrophages are one of the top players when considering immune cells involved with tissue homeostasis. Recently, increasing evidence has demonstrated that these macrophages could also present two major subsets during tissue healing; proliferative macrophages (M1-like), which are responsible for increasing myogenic cell proliferation, and restorative macrophages (M2-like), which are accountable for the end of the mature muscle myogenesis. The participation and characterization of these macrophage subsets is critical during myogenesis, not only to understand the inflammatory role of macrophages during muscle recovery but also to create supportive strategies that can improve mass muscle maintenance. Indeed, most of our knowledge about macrophage subsets comes from skeletal muscle damage protocols, and we still do not know how these subsets can contribute to skeletal muscle adaptation. This narrative review aims to collect and discuss studies demonstrating the involvement of different macrophage subsets during the skeletal muscle damage/regeneration process, showcasing an essential role of these macrophage subsets during muscle adaptation induced by acute and chronic exercise programs.
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Affiliation(s)
- André Luis Araujo Minari
- Universidade estadual Paulista, Campus Presidente Prudente, Brazil.,Universidade Federal de São Paulo, Psicobiologia, Brazil
| | - Ronaldo V Thomatieli-Santos
- Universidade Federal de São Paulo, Campus Baixada Santista, Brazil.,Universidade Federal de São Paulo, Psicobiologia, Brazil
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17
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Coelho-Júnior HJ. Is High-Speed Resistance Training an Efficient and Feasible Exercise Strategy for Frail Nursing Home Residents? J Am Med Dir Assoc 2021; 23:44-46. [PMID: 34736893 DOI: 10.1016/j.jamda.2021.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/27/2021] [Accepted: 10/02/2021] [Indexed: 10/20/2022]
Abstract
High-speed resistance training (HSRT) has been strongly recommended by experts in the field as a possible strategy to manage frailty in older adults; however, investigations to support this hypothesis are still lacking. Frailty is highly prevalent in nursing home residents and understanding if HSRT might contribute to frail patients' care is an urgent issue. Notably, frail older adults who live in long-term institutions commonly present reduced joint flexibility and cognitive resiliency. These characteristics might reduce the efficiency and feasibility of HSRT in frail nursing home residents. In the present, an evidence-based discussion about this topic is offered.
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18
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Eftestøl E, Franchi MV, Kasper S, Flück M. JNK activation in TA and EDL muscle is load-dependent in rats receiving identical excitation patterns. Sci Rep 2021; 11:16405. [PMID: 34385505 PMCID: PMC8361015 DOI: 10.1038/s41598-021-94930-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/12/2021] [Indexed: 11/09/2022] Open
Abstract
As the excitation-contraction coupling is inseparable during voluntary exercise, the relative contribution of the mechanical and neural input on hypertrophy-related molecular signalling is still poorly understood. Herein, we use a rat in-vivo strength exercise model with an electrically-induced standardized excitation pattern, previously shown to induce a load-dependent increase in myonuclear number and hypertrophy, to study acute effects of load on molecular signalling. We assessed protein abundance and specific phosphorylation of the four protein kinases FAK, mTOR, p70S6K and JNK after 2, 10 and 28 min of a low- or high-load contraction, in order to assess the effects of load, exercise duration and muscle-type on their response to exercise. Specific phosphorylation of mTOR, p70S6K and JNK was increased after 28 min of exercise under the low- and high-load protocol. Elevated phosphorylation of mTOR and JNK was detectable already after 2 and 10 min of exercise, respectively, but greatest after 28 min of exercise, and JNK phosphorylation was highly load-dependent. The abundance of all four kinases was higher in TA compared to EDL muscle, p70S6K abundance was increased after exercise in a load-independent manner, and FAK and JNK abundance was reduced after 28 min of exercise in both the exercised and control muscles. In conclusion, the current study shows that JNK activation after a single resistance exercise is load-specific, resembling the previously reported degree of myonuclear accrual and muscle hypertrophy with repetition of the exercise stimulus.
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Affiliation(s)
- Einar Eftestøl
- Department of Biosciences, University of Oslo, Kristine Bonnevies hus, Blindernveien 31, 0371, Oslo, Norway.
| | - Martino V Franchi
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland.,Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - Stephanie Kasper
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
| | - Martin Flück
- Laboratory for Muscle Plasticity, Department of Orthopaedics, University of Zürich, Zurich, Switzerland
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19
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Coelho-Júnior HJ, Uchida MC. Effects of Low-Speed and High-Speed Resistance Training Programs on Frailty Status, Physical Performance, Cognitive Function, and Blood Pressure in Prefrail and Frail Older Adults. Front Med (Lausanne) 2021; 8:702436. [PMID: 34381802 PMCID: PMC8350041 DOI: 10.3389/fmed.2021.702436] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/22/2021] [Indexed: 12/19/2022] Open
Abstract
Aim: The current study investigated the effects of low-speed resistance training (LSRT) and high-speed resistance training (HSRT) on frailty status, physical performance, cognitive function and blood pressure in pre-frail and frail older people. Material and Methods: Sixty older adults, 32 prefrail and 28 frail, were randomly allocated into LSRT, HSRT, and control group (CG). Before and after intervention periods frailty status, blood pressure, heart rate, and a set of physical performance capabilities and cognitive domains were assessed. Exercise interventions occurred over 16 weeks and included four resistance exercises with 4–8 sets of 4–10 repetitions at moderate intensity. Results: The prevalence of frailty criteria in prefrail and frail older adults were reduced after both LSRT and HSRT. In prefrail, LSRT significantly improved lower-limb muscle strength, while mobility was only improved after HSRT. Muscle power and dual-task performance were significantly increased in both LSRT and HSRT. In frail, LSRT and HSRT similarly improved lower-limb muscle strength and power. However, exclusive improvements in dual-task were observed after LSRT. Memory was significantly increased in prefrail and frail, regardless of the type of resistance training. No significant changes were observed in blood pressure and heart rate. Conclusion: Findings of the present study indicated that both LSRT and HSRT reversed frailty status and improved physical performance in prefrail and frail older adults. Notably, different patterns of improvement were observed among RT protocols. Regarding frailty status, LSRT seemed to be more effective in reverse prefrailty and frailty when compared to HSRT. Greater improvements in muscle strength and power were also observed after LSRT, while HSRT produced superior increases in mobility and dual-task performance. One-leg stand performance was significantly reduced in LSRT, but not HSRT and CG, after 16 weeks. In contrast, RT programs similarly improved verbal memory in prefrail. Finally, no changes in blood pressure and heart rate were observed, regardless of the type of RT. Trial Registration: The protocol was approved by the University of Campinas Human Research Ethics Committee (Protocol No. 20021919.7.0000.5404) and retrospectively registered at ClinicalTrials.gov Protocol Registration and Results System: NCT04868071.
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Affiliation(s)
- Hélio José Coelho-Júnior
- Laboratory of Applied Kinesiology, School of Physical Education, University of Campinas, Campinas, Brazil
| | - Marco Carlos Uchida
- Laboratory of Applied Kinesiology, School of Physical Education, University of Campinas, Campinas, Brazil
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20
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Haddock B, Hansen SK, Lindberg U, Nielsen JL, Frandsen U, Aagaard P, Larsson HBW, Suetta C. Exercise-induced fluid shifts are distinct to exercise mode and intensity: a comparison of blood flow-restricted and free-flow resistance exercise. J Appl Physiol (1985) 2021; 130:1822-1835. [PMID: 33914664 DOI: 10.1152/japplphysiol.01012.2020] [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] [Indexed: 11/22/2022] Open
Abstract
MRI can provide fundamental tools in decoding physiological stressors stimulated by training paradigms. Acute physiological changes induced by three diverse exercise protocols known to elicit similar levels of muscle hypertrophy were evaluated using muscle functional magnetic resonance imaging (mfMRI). The study was a cross-over study with participants (n = 10) performing three acute unilateral knee extensor exercise protocols to failure and a work matched control exercise protocol. Participants were scanned after each exercise protocol; 70% 1 repetition maximum (RM) (FF70); 20% 1RM (FF20); 20% 1RM with blood flow restriction (BFR20); free-flow (FF) control work matched to BFR20 (FF20WM). Post exercise mfMRI scans were used to obtain interleaved measures of muscle R2 (indicator of edema), R2' (indicator of deoxyhemoglobin), muscle cross sectional area (CSA) blood flow, and diffusion. Both BFR20 and FF20 exercise resulted in a larger acute decrease in R2, decrease in R2', and expansion of the extracellular compartment with slower rates of recovery. BFR20 caused greater acute increases in muscle CSA than FF20WM and FF70. Only BFR20 caused acute increases in intracellular volume. Postexercise muscle blood flow was higher after FF70 and FF20 exercise than BFR20. Acute changes in mean diffusivity were similar across all exercise protocols. This study was able to differentiate the acute physiological responses between anabolic exercise protocols. Low-load exercise protocols, known to have relatively higher energy contributions from glycolysis at task failure, elicited a higher mfMRI response. Noninvasive mfMRI represents a promising tool for decoding mechanisms of anabolic adaptation in muscle.NEW & NOTEWORTHY Using muscle functional MRI (mfMRI), this study was able to differentiate the acute physiological responses following three established hypertrophic resistance exercise strategies. Low-load exercise protocols performed to failure, with or without blood flow restriction, resulted in larger changes in R2 (i.e. greater T2-shifts) with a slow rate of return to baseline indicative of myocellular fluid shifts. These data were cross evaluated with interleaved measures of macrovascular blood flow, water diffusion, muscle cross sectional area (i.e. acute macroscopic muscle swelling), and intracellular water fraction measured using MRI.
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Affiliation(s)
- Bryan Haddock
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Sofie K Hansen
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Geriatric Research Unit, Department of Geriatric and Palliative Medicine, Bispebjerg and Frederiksberg Hospital, Copenhagen University Hospital, Copenhagen, Denmark
| | - Ulrich Lindberg
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark
| | - Jakob Lindberg Nielsen
- Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Ulrik Frandsen
- Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Per Aagaard
- Department of Sport Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
| | - Henrik B W Larsson
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Suetta
- Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark.,Geriatric Research Unit, Department of Geriatric and Palliative Medicine, Bispebjerg and Frederiksberg Hospital, Copenhagen University Hospital, Copenhagen, Denmark.,Geriatric Research Unit, Department of Medicine Herlev and Gentofte Hospital, Copenhagen University Hospital, Copenhagen, Denmark
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21
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Steinert ND, Potts GK, Wilson GM, Klamen AM, Lin KH, Hermanson JB, McNally RM, Coon JJ, Hornberger TA. Mapping of the contraction-induced phosphoproteome identifies TRIM28 as a significant regulator of skeletal muscle size and function. Cell Rep 2021; 34:108796. [PMID: 33657380 PMCID: PMC7967290 DOI: 10.1016/j.celrep.2021.108796] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 01/11/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022] Open
Abstract
Mechanical signals, such as those evoked by maximal-intensity contractions (MICs), can induce an increase in muscle mass. Rapamycin-sensitive signaling events are widely implicated in the regulation of this process; however, recent studies indicate that rapamycin-insensitive signaling events are also involved. Thus, to identify these events, we generate a map of the MIC-regulated and rapamycin-sensitive phosphoproteome. In total, we quantify more than 10,000 unique phosphorylation sites and find that more than 2,000 of these sites are significantly affected by MICs, but remarkably, only 38 of the MIC-regulated events are mediated through a rapamycin-sensitive mechanism. Further interrogation of the rapamycin-insensitive phosphorylation events identifies the S473 residue on Tripartite Motif-Containing 28 (TRIM28) as one of the most robust MIC-regulated phosphorylation sites, and extensive follow-up studies suggest that TRIM28 significantly contributes to the homeostatic regulation of muscle size and function as well as the hypertrophy that occurs in response to increased mechanical loading.
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Affiliation(s)
- Nathaniel D Steinert
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Gregory K Potts
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Gary M Wilson
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Amelia M Klamen
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Kuan-Hung Lin
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Jake B Hermanson
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Rachel M McNally
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA
| | - Joshua J Coon
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA; Genome Center of Wisconsin, University of Wisconsin-Madison, Madison, WI, USA; Morgridge Institute for Research, Madison, WI, USA; Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - Troy A Hornberger
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI, USA; School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, USA.
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22
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Naruse M, Fountain WA, Claiborne A, Chambers TL, Jones AM, Stroh AM, Montenegro CF, Lynch CE, Minchev K, Trappe S, Trappe TA. Influence of low-dose aspirin, resistance exercise, and sex on human skeletal muscle PGE 2 /COX pathway activity. Physiol Rep 2021; 9:e14790. [PMID: 33661544 PMCID: PMC7931802 DOI: 10.14814/phy2.14790] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/08/2021] [Accepted: 02/14/2021] [Indexed: 12/11/2022] Open
Abstract
Prostaglandin (PG) E2 has been linked to increased inflammation and attenuated resistance exercise adaptations in skeletal muscle. Nonaspirin cyclooxygenase (COX) inhibitors have been shown to reduce these effects. This study examined the effect of low-dose aspirin on skeletal muscle COX production of PGE2 at rest and following resistance exercise. Skeletal muscle (vastus lateralis) biopsies were taken from six individuals (4 M/2 W) before and 3.5 hr after a single bout of resistance exercise for ex vivo PGE2 production under control and low (10 μM)- or standard (100 μM)-dose aspirin conditions. Sex-specific effects of aspirin were also examined by combining the current findings with our previous similar ex vivo skeletal muscle investigations (n = 20, 10 M/10 W). Low-dose aspirin inhibited skeletal muscle PGE2 production (p < 0.05). This inhibition was similar to standard-dose aspirin (p > 0.05) and was not influenced by resistance exercise (p > 0.05) (overall effect: -18 ± 5%). Men and women had similar uninhibited skeletal muscle PGE2 production at rest (men: 1.97 ± 0.33, women: 1.96 ± 0.29 pg/mg wet weight/min; p > 0.05). However, skeletal muscle of men was 60% more sensitive to aspirin inhibition than women (p < 0.05). In summary, the current findings 1) confirm low-dose aspirin inhibits the PGE2 /COX pathway in human skeletal muscle, 2) show that resistance exercise does not alter aspirin inhibitory efficacy, and 3) suggest the skeletal muscle of men and women could respond differently to long-term consumption of low-dose aspirin, one of the most common chronically consumed drugs in the world.
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Affiliation(s)
| | | | - Alex Claiborne
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | | | - Andrew M. Jones
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | - Andrew M. Stroh
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | | | | | - Kiril Minchev
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | - Scott Trappe
- Human Performance LaboratoryBall State UniversityMuncieINUSA
| | - Todd A. Trappe
- Human Performance LaboratoryBall State UniversityMuncieINUSA
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23
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Clegg MH, Harris TI, Zhang X, Barney JT, Jones JA, Vargis E. Silkworm Silk Fiber Bundles as Improved In Vitro Scaffolds for Skeletal Muscle. ACS Biomater Sci Eng 2020; 6:6853-6863. [PMID: 33320626 DOI: 10.1021/acsbiomaterials.0c00987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To mimic skeletal muscle tissues in vitro, native and transgenic spider silk/silkworm silks were seeded with C2C12 myoblasts to observe if these three-dimensional substrates are preferable to a traditional two-dimensional polystyrene cell culture surface. Silks were wound around an acrylic chassis to produce a novel, three-dimensional cell culture device with suspended muscle fibers that genetically and morphologically resemble native skeletal muscle tissue. The transgenic spider silk/silkworm silk has never before been studied for this application. Genetic expression verified skeletal muscle lineage and differentiation, while fluorescent imaging verified contractile protein synthesis. Genetic analysis also revealed an increase in expression of the Myh2 contractile protein gene on silkworm silks, particularly on the transgenic silk. Mechanical properties and protein secondary structure content of the silks indicated correlation between substrate properties and Myh2 gene expression. This increase in contractile protein gene expression suggests that biologically derived silk substrates that are suspended may be a preferable substrate for in vitro muscle modeling because of the proteinaceous character and mechanical flexibility of the silk.
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Affiliation(s)
- Matthew H Clegg
- Department of Biological Engineering, Utah State University, Logan, Utah 84322, United States
| | - Thomas I Harris
- Department of Biology, Utah State University, Logan, Utah 84322, United States
| | - Xiaoli Zhang
- Department of Biology, Utah State University, Logan, Utah 84322, United States
| | - Jacob T Barney
- Department of Biological Engineering, Utah State University, Logan, Utah 84322, United States
| | - Justin A Jones
- Department of Biology, Utah State University, Logan, Utah 84322, United States
| | - Elizabeth Vargis
- Department of Biological Engineering, Utah State University, Logan, Utah 84322, United States
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24
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Veziroglu EM, Mias GI. Characterizing Extracellular Vesicles and Their Diverse RNA Contents. Front Genet 2020; 11:700. [PMID: 32765582 PMCID: PMC7379748 DOI: 10.3389/fgene.2020.00700] [Citation(s) in RCA: 139] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 06/09/2020] [Indexed: 12/15/2022] Open
Abstract
Cells release nanometer-scale, lipid bilayer-enclosed biomolecular packages (extracellular vesicles; EVs) into their surrounding environment. EVs are hypothesized to be intercellular communication agents that regulate physiological states by transporting biomolecules between near and distant cells. The research community has consistently advocated for the importance of RNA contents in EVs by demonstrating that: (1) EV-related RNA contents can be detected in a liquid biopsy, (2) disease states significantly alter EV-related RNA contents, and (3) sensitive and specific liquid biopsies can be implemented in precision medicine settings by measuring EV-derived RNA contents. Furthermore, EVs have medical potential beyond diagnostics. Both natural and engineered EVs are being investigated for therapeutic applications such as regenerative medicine and as drug delivery agents. This review focuses specifically on EV characterization, analysis of their RNA content, and their functional implications. The NIH extracellular RNA communication (ERC) program has catapulted human EV research from an RNA profiling standpoint by standardizing the pipeline for working with EV transcriptomics data, and creating a centralized database for the scientific community. There are currently thousands of RNA-sequencing profiles hosted on the Extracellular RNA Atlas alone (Murillo et al., 2019), encompassing a variety of human biofluid types and health conditions. While a number of significant discoveries have been made through these studies individually, integrative analyses of these data have thus far been limited. A primary focus of the ERC program over the next five years is to bring higher resolution tools to the EV research community so that investigators can isolate and analyze EV sub-populations, and ultimately single EVs sourced from discrete cell types, tissues, and complex biofluids. Higher resolution techniques will be essential for evaluating the roles of circulating EVs at a level which impacts clinical decision making. We expect that advances in microfluidic technologies will drive near-term innovation and discoveries about the diverse RNA contents of EVs. Long-term translation of EV-based RNA profiling into a mainstay medical diagnostic tool will depend upon identifying robust patterns of circulating genetic material that correlate with a change in health status.
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Affiliation(s)
- Eren M. Veziroglu
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States
- Department of Biomedical Engineering, Michigan State University, East Lansing, MI, United States
| | - George I. Mias
- Institute for Quantitative Health Science and Engineering, Michigan State University, East Lansing, MI, United States
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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25
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Murach KA, McCarthy JJ, Peterson CA, Dungan CM. Making Mice Mighty: recent advances in translational models of load-induced muscle hypertrophy. J Appl Physiol (1985) 2020; 129:516-521. [PMID: 32673155 DOI: 10.1152/japplphysiol.00319.2020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The ability to genetically manipulate mice allows for gain- and loss-of-function in vivo, making them an ideal model for elucidating mechanisms of skeletal muscle mass regulation. Combining genetic models with mechanical muscle loading enables identification of specific factors involved in the hypertrophic response as well as the ability to test the requirement of those factors for adaptation, thereby informing performance and therapeutic interventions. Until recently, approaches for inducing mechanically mediated muscle hypertrophy (i.e., resistance-training analogs) have been limited and considered "nontranslatable" to humans. This mini-review outlines recent translational advances in loading-mediated strategies for inducing muscle hypertrophy in mice, and highlights the advantages and disadvantages of each method. The skeletal muscle field is poised for new breakthroughs in understanding mechanisms regulating load-induced muscle growth given the numerous murine tools that have very recently been described.
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Affiliation(s)
- Kevin A Murach
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky
| | - John J McCarthy
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Charlotte A Peterson
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky.,Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - Cory M Dungan
- The Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.,Department of Physical Therapy, College of Health Sciences, University of Kentucky, Lexington, Kentucky
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26
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Ravn MK, Ostergaard TI, Schroeder HD, Nyengaard JR, Lambertsen KL, Frich LH. Supraspinatus and deltoid muscle fiber composition in rotator cuff tear conditions. JSES Int 2020; 4:431-437. [PMID: 32939464 PMCID: PMC7479021 DOI: 10.1016/j.jseint.2020.04.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Background Rotator cuff (RC) tears are associated with RC muscle atrophy and changes in composition that are crucial to the prognosis of RC repair. The aim of this study was to characterize muscle fiber composition in the supraspinatus (SS) muscle under tear conditions. Methods Muscle biopsies were obtained from 21 patients undergoing surgery for an RC tendon tear. Biopsies were obtained from the musculotendinous junction of the SS muscle, and control biopsies were harvested from the deltoid muscle (DT). Biopsies were immunohistochemically processed for detection of type 1 (slow type) and type 2 (fast type) fibers and analyzed using unbiased, stereological principles. We counted the total numbers of type 1 and 2 muscle fibers/mm2, and fiber diameter was used to estimate muscle fiber atrophy and hypertrophy. Results We found significantly more type 2 cells/mm2 in the SS compared with the DT (P < .01). In addition, we found a significantly higher fraction of type 1 fibers than type 2 fibers in the DT (P < .01), whereas both fiber types were equally present in the SS. The diameters of SS cells were generally smaller than those of DT cells. Atrophy of especially SS type 2 fibers was also demonstrated. Fiber atrophy was more pronounced in men than women. Conclusion The changes in the composition of SS muscle cell types suggest a shift from type 1 to type 2 muscle fibers and atrophy of both type 1 and 2 fibers. This composition indicates loss of endurance and rapid fatigue of the SS muscle under RC tear conditions.
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Affiliation(s)
- Morten Kjaer Ravn
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Trine Ivarsen Ostergaard
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | | | - Jens Randel Nyengaard
- Department of Clinical Medicine - Core Centre for Molecular Morphology, Section for Stereology and Microscopy, Center for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Aarhus, Denmark
| | - Kate Lykke Lambertsen
- Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark.,BRIDGE - Brain Research - Inter-Disciplinary Guided Excellence, Department of Clinical Research, University of Southern Denmark, Odense, Denmark
| | - Lars Henrik Frich
- Department of Orthopaedics, Odense University Hospital, Odense, Denmark.,The Orthopaedic Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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27
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A focused review of myokines as a potential contributor to muscle hypertrophy from resistance-based exercise. Eur J Appl Physiol 2020; 120:941-959. [PMID: 32144492 DOI: 10.1007/s00421-020-04337-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023]
Abstract
PURPOSE Resistance exercise induces muscle growth and is an important treatment for age-related losses in muscle mass and strength. Myokines are hypothesized as a signal conveying physiological information to skeletal muscle, possibly to "fine-tune" other regulatory pathways. While myokines are released from skeletal muscle following contraction, their role in increasing muscle mass and strength in response to resistance exercise or training is not established. Recent research identified both local and systemic release of myokines after an acute bout of resistance exercise. However, it is not known whether myokines with putative anabolic function are mechanistically involved in producing muscle hypertrophy after resistance exercise. Further, nitric oxide (NO), an important mediator of muscle stem cell activation, upregulates the expression of certain myokine genes in skeletal muscle. METHOD In the systemic context of complex hypertrophic signaling, this review: (1) summarizes literature on several well-recognized, representative myokines with anabolic potential; (2) explores the potential mechanistic role of myokines in skeletal muscle hypertrophy; and (3) identifies future research required to advance our understanding of myokine anabolism specifically in skeletal muscle. RESULT This review establishes a link between myokines and NO production, and emphasizes the importance of considering systemic release of potential anabolic myokines during resistance exercise as complementary to other signals that promote hypertrophy. CONCLUSION Investigating adaptations to resistance exercise in aging opens a novel avenue of interdisciplinary research into myokines and NO metabolites during resistance exercise, with the longer-term goal to improve muscle health in daily living, aging, and rehabilitation.
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28
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Maiole F, Giachero S, Fossati SM, Rocchi A, Zullo L. mTOR as a Marker of Exercise and Fatigue in Octopus vulgaris Arm. Front Physiol 2019; 10:1161. [PMID: 31572212 PMCID: PMC6749024 DOI: 10.3389/fphys.2019.01161] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 08/28/2019] [Indexed: 01/07/2023] Open
Abstract
Cephalopods are highly evolved marine invertebrates that colonized almost all the oceans of the world at all depths. This imposed the occurrence of several modifications of their brain and body whose muscle component represents the major constituent. Hence, studying their muscle physiology may give important hints in the context of animal biology and environmental adaptability. One major pathway involved in muscle metabolism in vertebrates is the evolutionary conserved mTOR-signaling cascade; however, its role in cephalopods has never been elucidated. mTOR is regulating cell growth and homeostasis in response to a wide range of cues such as nutrient availability, body temperature and locomotion. It forms two functionally heteromeric complexes, mTORC1 and mTORC2. mTORC1 regulates protein synthesis and degradation and, in skeletal muscles, its activation upon exercise induces muscle growth. In this work, we characterized Octopus vulgaris mTOR full sequence and functional domains; we found a high level of homology with vertebrates’ mTOR and the conservation of Ser2448 phosphorylation site required for mTORC1 activation. We then designed and tested an in vitro protocol of resistance exercise (RE) inducing fatigue in arm samples. We showed that, upon the establishment of fatigue, a transient increase in mTORC1 phosphorylation reaching a pick 30 min after exercise was induced. Our data indicate the activation of mTORC1 pathway in exercise paradigm and possibly in the regulation of energy homeostasis in octopus and suggest that mTORC1 activity can be used to monitor animal response to changes in physiological and ecological conditions and, more in general, the animal welfare.
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Affiliation(s)
- Federica Maiole
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sarah Giachero
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Sara Maria Fossati
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy
| | - Anna Rocchi
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,IRCSS Ospedale Policlinico San Martino, Genoa, Italy
| | - Letizia Zullo
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, Genoa, Italy.,IRCSS Ospedale Policlinico San Martino, Genoa, Italy
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29
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Barakat C, Barroso R, Alvarez M, Rauch J, Miller N, Bou-Sliman A, De Souza EO. The Effects of Varying Glenohumeral Joint Angle on Acute Volume Load, Muscle Activation, Swelling, and Echo-Intensity on the Biceps Brachii in Resistance-Trained Individuals. Sports (Basel) 2019; 7:sports7090204. [PMID: 31487841 PMCID: PMC6783981 DOI: 10.3390/sports7090204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Revised: 08/31/2019] [Accepted: 09/02/2019] [Indexed: 12/04/2022] Open
Abstract
There is a paucity of data on how manipulating joint angles during isolation exercises may impact overall session muscle activation and volume load in resistance-trained individuals. We investigated the acute effects of varying glenohumeral joint angle on the biceps brachii with a crossover repeated measure design with three different biceps curls. One session served as the positive control (CON), which subjects performed 9 sets of bicep curls with their shoulder in a neutral position. The experimental condition (VAR), varied the glenohumeral joint angle by performing 3 sets in shoulder extension (30°), 3 sets neutral (0°), and 3 sets in flexion (90°). Volume load and muscle activation (EMG) were recorded during the training sessions. Muscle swelling and strain were assessed via muscle thickness and echo-intensity responses at pre, post, 24 h, 48 h, and 72 h. There were no significant differences between conditions for most dependent variables. However, the overall session EMG amplitude was significantly higher (p = 0.0001) in VAR compared to CON condition (95%-CI: 8.4% to 23.3%). Our findings suggest that varying joint angles during resistance training (RT) may enhance total muscle activation without negatively affecting volume load within a training session in resistance-trained individuals.
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Affiliation(s)
- Christopher Barakat
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Renato Barroso
- School of Physical Education, University of Campinas, Campinas 13083-851, Brazil.
| | - Michael Alvarez
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Jacob Rauch
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Nicholas Miller
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Anton Bou-Sliman
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Eduardo O De Souza
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
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30
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You JS, McNally RM, Jacobs BL, Privett RE, Gundermann DM, Lin KH, Steinert ND, Goodman CA, Hornberger TA. The role of raptor in the mechanical load-induced regulation of mTOR signaling, protein synthesis, and skeletal muscle hypertrophy. FASEB J 2019; 33:4021-4034. [PMID: 30509128 PMCID: PMC6404572 DOI: 10.1096/fj.201801653rr] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Accepted: 11/05/2018] [Indexed: 12/21/2022]
Abstract
It is well known that an increase in mechanical loading can induce skeletal muscle hypertrophy, and a long standing model in the field indicates that mechanical loads induce hypertrophy via a mechanism that requires signaling through the mechanistic target of rapamycin complex 1 (mTORC1). Specifically, it has been widely proposed that mechanical loads activate signaling through mTORC1 and that this, in turn, promotes an increase in the rate of protein synthesis and the subsequent hypertrophic response. However, this model is based on a number of important assumptions that have not been rigorously tested. In this study, we created skeletal muscle specific and inducible raptor knockout mice to eliminate signaling by mTORC1, and with these mice we were able to directly demonstrate that mechanical stimuli can activate signaling by mTORC1, and that mTORC1 is necessary for mechanical load-induced hypertrophy. Surprisingly, however, we also obtained multiple lines of evidence that indicate that mTORC1 is not required for a mechanical load-induced increase in the rate of protein synthesis. This observation highlights an important shortcoming in our understanding of how mechanical loads induce hypertrophy and illustrates that additional mTORC1-independent mechanisms play a critical role in this process.-You, J.-S., McNally, R. M., Jacobs, B. L., Privett, R. E., Gundermann, D. M., Lin, K.-H., Steinert, N. D., Goodman, C. A., Hornberger, T. A. The role of raptor in the mechanical load-induced regulation of mTOR signaling, protein synthesis, and skeletal muscle hypertrophy.
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Affiliation(s)
- Jae-Sung You
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Rachel M. McNally
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Brittany L. Jacobs
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Rachel E. Privett
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - David M. Gundermann
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Kuan-Hung Lin
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Nate D. Steinert
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
| | - Craig A. Goodman
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
- Institute of Health and Sport, Victoria University, Melbourne, Victoria, Australia
- Australian Institute for Musculoskeletal Science, Victoria University, St. Albans, Victoria, Australia
| | - Troy A. Hornberger
- Department of Comparative Biosciences, University of Wisconsin–Madison, Madison, Wisconsin, USA
- School of Veterinary Medicine, University of Wisconsin–Madison, Madison, Wisconsin, USA
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Wallace W, Ugrinowitsch C, Stefan M, Rauch J, Barakat C, Shields K, Barninger A, Barroso R, De Souza EO. Repeated Bouts of Advanced Strength Training Techniques: Effects on Volume Load, Metabolic Responses, and Muscle Activation in Trained Individuals. Sports (Basel) 2019; 7:sports7010014. [PMID: 30621334 PMCID: PMC6359665 DOI: 10.3390/sports7010014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/18/2018] [Accepted: 01/02/2019] [Indexed: 11/16/2022] Open
Abstract
This study investigated the effects of advanced training techniques (ATT) on muscular responses and if performing a second training session would negatively affect the training stimulus. Eleven strength-trained males performed a traditional strength training session (TST) and four different ATT: pre-exhaustion A (PE-A), pre-exhaustion B (PE-B), forced repetitions (FR), and super-set (SS). On day 1, SS produced lower volume load than TST, FR, and PE-B (−16.0%, p ≤ 0.03; −14.9, p ≤ 0.03 and −18.2%, p ≤ 0.01, respectively). On day 2, SS produced lower volumes than all the other ATT (−9.73–−18.5%, p ≤ 0.03). Additionally, subjects demonstrated lower perceived exertion on day 1 compared to day 2 (6.5 ± 0.4 AU vs. 8.7 ± 0.3 AU, p = 0.0001). For blood lactate concentration [La-] on days 1 and 2, [La-] after the tenth set was the highest compared to all other time points (baseline: 1.7 ± 0.2, fifth-set: 8.7 ± 1.0, tenth-set 9.7 ± 0.9, post-5 min: 8.7 ± 0.7 mmol∙L−1, p ≤ 0.0001). Acute muscle swelling was greater immediately and 30-min post compared to baseline (p ≤ 0.0001). On day 2, electromyography (EMG) amplitude on the clavicular head of the pectoralis major was lower for SS than TST, PE-A, and PE-B (−11.7%, p ≤ 0.01; −14.4%, p ≤ 0.009; −20.9%, p = 0.0003, respectively). Detrimental effects to the training stimulus were not observed when ATT (besides SS) are repeated. Strength trained individuals can sustain performance, compared to TST, when they are using ATT in an acute fashion. Although ATT have traditionally been used as a means to optimize metabolic stress, volume load, and neuromuscular responses, our data did not project differences in these variables compared to TST. However, it is important to note that different ATT might produce slight changes in volume load, muscle excitation, and fluid accumulation in strength-trained individuals from session to session.
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Affiliation(s)
- William Wallace
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
- Leadership-Health and Human Performance Department, Concordia University Chicago, River Forrest, IL 60305, USA.
| | - Carlos Ugrinowitsch
- Laboratory of Adaptations to Strength Training, School of Physical Education and Sport, University of Sao Paulo, São Paulo 05508-030, Brazil.
| | - Matt Stefan
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Jacob Rauch
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Christopher Barakat
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Kevin Shields
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
| | - Andrew Barninger
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
- Leadership-Health and Human Performance Department, Concordia University Chicago, River Forrest, IL 60305, USA.
| | - Renato Barroso
- School of Physical Education, University of Campinas, Campinas 13083-851, Brazil.
| | - Eduardo O De Souza
- Department of Health Science and Human Performance, University of Tampa, Tampa, FL 33606, USA.
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33
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Exercise and the control of muscle mass in human. Pflugers Arch 2018; 471:397-411. [DOI: 10.1007/s00424-018-2217-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/19/2022]
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Yarar-Fisher C, Polston KFL, Eraslan M, Henley KY, Kinikli GI, Bickel CS, Windham ST, McLain AB, Oster RA, Bamman MM. Paralytic and nonparalytic muscle adaptations to exercise training versus high-protein diet in individuals with long-standing spinal cord injury. J Appl Physiol (1985) 2018; 125:64-72. [PMID: 29494292 PMCID: PMC6086973 DOI: 10.1152/japplphysiol.01029.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2017] [Revised: 01/31/2018] [Accepted: 02/28/2018] [Indexed: 02/08/2023] Open
Abstract
This study compares the effects of an 8-wk isocaloric high-protein (HP) diet versus a combination exercise (Comb-Ex) regimen on paralytic vastus lateralis (VL) and nonparalytic deltoid muscle in individuals with long-standing spinal cord injury (SCI). Fiber-type distribution, cross-sectional area (CSA), levels of translation initiation signaling proteins (Erk-1/2, Akt, p70S6K1, 4EBP1, RPS6, and FAK), and lean thigh mass were analyzed at baseline and after the 8-wk interventions. A total of 11 participants (C5-T12 levels, 21.8 ± 6.3 yr postinjury; 6 Comb-Ex and 5 HP diet) completed the study. Comb-Ex training occurred 3 days/wk and consisted of upper body resistance training (RT) in addition to neuromuscular electrical stimulation (NMES)-induced-RT for paralytic VL muscle. Strength training was combined with high-intensity arm-cranking exercises (1-min intervals at 85-90%, V̇o2peak) for improving cardiovascular endurance. For the HP diet intervention, protein and fat each comprised 30%, and carbohydrate comprised 40% of total energy. Clinical tests and muscle biopsies were performed 24 h before and after the last exercise or diet session. The Comb-Ex intervention increased Type IIa myofiber distribution and CSA in VL muscle and Type I and IIa myofiber CSA in deltoid muscle. In addition, Comb-Ex increased lean thigh mass, V̇o2peak, and upper body strength ( P < 0.05). These results suggest that exercise training is required to promote favorable changes in paralytic and nonparalytic muscles in individuals with long-standing SCI, and adequate dietary protein consumption alone may not be sufficient to ameliorate debilitating effects of paralysis. NEW & NOTEWORTHY This study is the first to directly compare the effects of an isocaloric high-protein diet and combination exercise training on clinical and molecular changes in paralytic and nonparalytic muscles of individuals with long-standing spinal cord injury. Our results demonstrated that muscle growth and fiber-type alterations can best be achieved when the paralyzed muscle is sufficiently loaded via neuromuscular electrical stimulation-induced resistance training.
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Affiliation(s)
- Ceren Yarar-Fisher
- Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
- University of Alabama at Birmingham Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Keith F L Polston
- University of Tennessee Health Science Center College of Medicine , Memphis, Tennessee
| | - Mualla Eraslan
- Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
| | - Kathryn Y Henley
- Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
| | - Gizem I Kinikli
- Physical Therapy and Rehabilitation, Hacettepe University , Ankara , Turkey
| | - C Scott Bickel
- Physical Therapy and Rehabilitation, Samford University , Birmingham, Alabama
| | - Samuel T Windham
- Department of Surgery, University of Alabama at Birmingham , Birmingham, Alabama
- University of Alabama at Birmingham Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Amie B McLain
- Physical Medicine and Rehabilitation, University of Alabama at Birmingham , Birmingham, Alabama
- University of Alabama at Birmingham Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Robert A Oster
- Department of Medicine/Division of Preventive Medicine, University of Alabama at Birmingham , Birmingham, Alabama
| | - Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham , Birmingham, Alabama
- University of Alabama at Birmingham Center for Exercise Medicine, University of Alabama at Birmingham , Birmingham, Alabama
- Geriatric Research, Education, and Clinical Center, Birmingham VA Medical Center , Birmingham, Alabama
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Fisher J, Steele J, Smith D. High- and Low-Load Resistance Training: Interpretation and Practical Application of Current Research Findings. Sports Med 2018; 47:393-400. [PMID: 27480764 DOI: 10.1007/s40279-016-0602-1] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Our current state of knowledge regarding the load (lighter or heavier) lifted in resistance training programmes that will result in 'optimal' strength and hypertrophic adaptations is unclear. Despite this, position stands and recommendations are made based on, we propose, limited evidence to lift heavier weights. Here we discuss the state of evidence on the impact of load and how it, as a single variable, stimulates adaptations to take place and whether evidence for recommending heavier loads is available, well-defined, currently correctly interpreted or has been overlooked. Areas of discussion include electromyography amplitude, in vivo and in vitro methods of measuring hypertrophy, and motor schema and skill acquisition. The present piece clarifies to trainers and trainees the impact of these variables by discussing interpretation of synchronous and sequential motor unit recruitment and revisiting the size principle, poor agreement between whole-muscle cross-sectional area (CSA) and biopsy-determined changes in myofibril CSA, and neural adaptations around task specificity. Our opinion is that the practical implications of being able to self-select external load include reducing the need for specific facility memberships, motivating older persons or those who might be less confident using heavy loads, and allowing people to undertake home- or field-based resistance training intervention strategies that might ultimately improve exercise adherence.
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Affiliation(s)
- James Fisher
- Southampton Solent University, East Park Terrace, Southampton, SO14 0YN, UK.
| | - James Steele
- Southampton Solent University, East Park Terrace, Southampton, SO14 0YN, UK
| | - Dave Smith
- Manchester Metropolitan University, Crewe, UK
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Bamman MM, Roberts BM, Adams GR. Molecular Regulation of Exercise-Induced Muscle Fiber Hypertrophy. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a029751. [PMID: 28490543 DOI: 10.1101/cshperspect.a029751] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Skeletal muscle hypertrophy is a widely sought exercise adaptation to counteract the muscle atrophy of aging and disease, or to improve athletic performance. While this desired muscle enlargement is a well-known adaptation to resistance exercise training (RT), the mechanistic underpinnings are not fully understood. The purpose of this review is thus to provide the reader with a summary of recent advances in molecular mechanisms-based on the most current literature-that are thought to promote RT-induced muscle hypertrophy. We have therefore focused this discussion on the following areas of fertile investigation: ribosomal function and biogenesis, muscle stem (satellite) cell activity, transcriptional regulation, mechanotransduction, and myokine signaling.
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Affiliation(s)
- Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294.,UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35205.,Geriatric Research, Education, and Clinical Center, Veterans' Affairs Medical Center, Birmingham, Alabama 35233
| | - Brandon M Roberts
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294.,UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35205
| | - Gregory R Adams
- Department of Physiology and Biophysics, University of California Irvine, Irvine, California 92617
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Simoes DCM, Vogiatzis I. Can muscle protein metabolism be specifically targeted by exercise training in COPD? J Thorac Dis 2018; 10:S1367-S1376. [PMID: 29928519 DOI: 10.21037/jtd.2018.02.67] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Patients with stable chronic obstructive pulmonary disease (COPD) frequently exhibit unintentional accentuated peripheral muscle loss and dysfunction. Skeletal muscle mass in these patients is a strong independent predictor of morbidity and mortality. Factors including protein anabolism/catabolism imbalance, hypoxia, physical inactivity, inflammation, and oxidative stress are involved in the initiation and progression of muscle wasting in these patients. Exercise training remains the most powerful intervention for reversing, in part, muscle wasting in COPD. Independently of the status of systemic or local muscle inflammation, rehabilitative exercise training induces up-regulation of key factors governing skeletal muscle hypertrophy and regeneration. However, COPD patients presenting similar degrees of lung dysfunction do not respond alike to a given rehabilitative exercise stimulus. In addition, a proportion of patients experience limited clinical outcomes, even when exercise training has been adequately performed. Consistently, several reports provide evidence that the muscles of COPD patients present training-induced myogenic activity limitation as exercise training induces a limited number of differentially expressed genes, which are mostly associated with protein degradation. This review summarises the nature of muscle adaptations induced by exercise training, promoted both by changes in the expression of contractile proteins and their function typically controlled by intracellular signalling and transcriptional responses. Rehabilitative exercise training in COPD patients stimulates skeletal muscle mechanosensitive signalling pathways for protein accretion and its regulation during muscle contraction. Exercise training also induces synthesis of myogenic proteins by which COPD skeletal muscle promotes hypertrophy leading to fusion of myogenic cells to the myofiber. Understanding of the biological mechanisms that regulate exercise training-induced muscle growth and regeneration is necessary for implementing therapeutic strategies specifically targeting myogenesis and hypertrophy in these patients.
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Affiliation(s)
- Davina C M Simoes
- Department of Applied Sciences, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, UK
| | - Ioannis Vogiatzis
- Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle-upon-Tyne, UK
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Howe LP, Read P, Waldron M. Muscle Hypertrophy: A Narrative Review on Training Principles for Increasing Muscle Mass. Strength Cond J 2017. [DOI: 10.1519/ssc.0000000000000330] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Stec MJ, Thalacker-Mercer A, Mayhew DL, Kelly NA, Tuggle SC, Merritt EK, Brown CJ, Windham ST, Dell'Italia LJ, Bickel CS, Roberts BM, Vaughn KM, Isakova-Donahue I, Many GM, Bamman MM. Randomized, four-arm, dose-response clinical trial to optimize resistance exercise training for older adults with age-related muscle atrophy. Exp Gerontol 2017; 99:98-109. [PMID: 28964826 DOI: 10.1016/j.exger.2017.09.018] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 07/25/2017] [Accepted: 09/25/2017] [Indexed: 01/08/2023]
Abstract
PURPOSE The myriad consequences of age-related muscle atrophy include reduced muscular strength, power, and mobility; increased risk of falls, disability, and metabolic disease; and compromised immune function. At its root, aging muscle atrophy results from a loss of myofibers and atrophy of the remaining type II myofibers. The purpose of this trial (NCT02442479) was to titrate the dose of resistance training (RT) in older adults in an effort to maximize muscle regrowth and gains in muscle function. METHODS A randomized, four-arm efficacy trial in which four, distinct exercise prescriptions varying in intensity, frequency, and contraction mode/rate were evaluated: (1) high-resistance concentric-eccentric training (H) 3d/week (HHH); (2) H training 2d/week (HH); (3) 3d/week mixed model consisting of H training 2d/week separated by 1 bout of low-resistance, high-velocity, concentric only (L) training (HLH); and (4) 2d/week mixed model consisting of H training 1d/week and L training 1d/week (HL). Sixty-four randomized subjects (65.5±3.6y) completed the trial. All participants completed the same 4weeks of pre-training consisting of 3d/week followed by 30weeks of randomized RT. RESULTS The HLH prescription maximized gains in thigh muscle mass (TMM, primary outcome) and total body lean mass. HLH also showed the greatest gains in knee extension maximum isometric strength, and reduced cardiorespiratory demand during steady-state walking. HHH was the only prescription that led to increased muscle expression of pro-inflammatory cytokine receptors and this was associated with a lesser gain in TMM and total body lean mass compared to HLH. The HL prescription induced minimal muscle regrowth and generally lesser gains in muscle performance vs. the other prescriptions. MAJOR CONCLUSIONS The HLH prescription offers distinct advantages over the other doses, while the HL program is subpar. Although limited by a relatively small sample size, we conclude from this randomized dose-response trial that older adults benefit greatly from 2d/week high-intensity RT, and may further benefit from inserting an additional weekly bout of low-load, explosive RT. TRIAL REGISTRATION ClinicalTrials.govNCT02442479.
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Affiliation(s)
- Michael J Stec
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Anna Thalacker-Mercer
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - David L Mayhew
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Neil A Kelly
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - S Craig Tuggle
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Edward K Merritt
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Cynthia J Brown
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Geriatric Research, Education, and Clinical Center, Veterans' Affairs Medical Center, Birmingham, AL 35233, United States
| | - Samuel T Windham
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Surgery, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Louis J Dell'Italia
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Division of Cardiovascular Disease, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Research Service, Veterans' Affairs Medical Center, Birmingham, AL 35233, United States
| | - C Scott Bickel
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Brandon M Roberts
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Kristina M Vaughn
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Irina Isakova-Donahue
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Gina M Many
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States
| | - Marcas M Bamman
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, United States; Geriatric Research, Education, and Clinical Center, Veterans' Affairs Medical Center, Birmingham, AL 35233, United States.
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Kelly NA, Hammond KG, Stec MJ, Bickel CS, Windham ST, Tuggle SC, Bamman MM. Quantification and characterization of grouped type I myofibers in human aging. Muscle Nerve 2017; 57:E52-E59. [PMID: 28561923 DOI: 10.1002/mus.25711] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 05/02/2017] [Accepted: 05/28/2017] [Indexed: 11/06/2022]
Abstract
INTRODUCTION Myofiber type grouping is a histological hallmark of age-related motor unit remodeling. Despite the accepted concept that denervation-reinnervation events lead to myofiber type grouping, the completeness of those conversions remains unknown. METHODS Type I myofiber grouping was assessed in vastus lateralis biopsies from Young (26 ± 4 years; n = 27) and Older (66 ± 4 years; n = 91) adults. Grouped and ungrouped type I myofibers were evaluated for phenotypic differences. RESULTS Higher type I grouping in Older versus Young was driven by more myofibers per group (i.e., larger group size) (P < 0.05). In Older only, grouped type I myofibers displayed larger cross-sectional area, more myonuclei, lower capillary supply, and more sarco(endo)plasmic reticulum calcium ATPase I (SERCA I) expression (P < 0.05) than ungrouped type I myofibers. DISCUSSION Grouped type I myofibers retain type II characteristics suggesting that conversion during denervation-reinnervation events is either progressive or incomplete. Muscle Nerve 57: E52-E59, 2018.
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Affiliation(s)
- Neil A Kelly
- Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA
| | - Kelley G Hammond
- UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA.,Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Michael J Stec
- Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA
| | - C Scott Bickel
- UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA.,Department of Physical Therapy, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Samuel T Windham
- UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA.,Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - S Craig Tuggle
- Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA
| | - Marcas M Bamman
- Departments of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,UAB Center for Exercise Medicine, 1313 13th Street South, OSB Room 300, University of Alabama at Birmingham, Birmingham, Alabama, 35205-5327, USA.,Geriatric Research, Education, and Clinical Center, VA Medical Center, Birmingham, Alabama, USA
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Oleate Prevents Palmitate-Induced Atrophy via Modulation of Mitochondrial ROS Production in Skeletal Myotubes. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:2739721. [PMID: 28947926 PMCID: PMC5602654 DOI: 10.1155/2017/2739721] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 07/26/2017] [Accepted: 08/08/2017] [Indexed: 12/25/2022]
Abstract
Accumulation of saturated fatty acids contributes to lipotoxicity-related insulin resistance and atrophy in skeletal muscle. Conversely, unsaturated fatty acids like docosahexaenoic acid were proven to preserve muscle mass. However, it is not known if the most common unsaturated oleate will protect skeletal myotubes against palmitate-mediated atrophy, and its specific mechanism remains to be elucidated. Therefore, we investigated the effects of oleate on atrophy-related factors in palmitate-conditioned myotubes. Exposure of myotubes to palmitate, but not to oleate, led to an induction of fragmented nuclei, myotube loss, atrophy, and mitochondrial superoxide in a dose-dependent manner. Treatment of oleate to myotubes attenuated production of palmitate-induced mitochondrial superoxide in a dose-dependent manner. The treatment of oleate or MitoTEMPO to palmitate-conditioned myotubes led to inhibition of palmitate-induced mRNA expression of proinflammatory (TNF-α and IL6), mitochondrial fission (Drp1 and Fis1), and atrophy markers (myostatin and atrogin1). In accordance with the gene expression data, our immunocytochemistry experiment demonstrated that oleate and MitoTEMPO prevented or attenuated palmitate-mediated myotube shrinkage. These results provide a mechanism indicating that oleate prevents palmitate-mediated atrophy via at least partial modulation of mitochondrial superoxide production.
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Potts GK, McNally RM, Blanco R, You J, Hebert AS, Westphall MS, Coon JJ, Hornberger TA. A map of the phosphoproteomic alterations that occur after a bout of maximal-intensity contractions. J Physiol 2017; 595:5209-5226. [PMID: 28542873 PMCID: PMC5538225 DOI: 10.1113/jp273904] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/11/2017] [Indexed: 12/25/2022] Open
Abstract
KEY POINTS Mechanical signals play a critical role in the regulation of muscle mass, but the molecules that sense mechanical signals and convert this stimulus into the biochemical events that regulate muscle mass remain ill-defined. Here we report a mass spectrometry-based workflow to study the changes in protein phosphorylation that occur in mouse skeletal muscle 1 h after a bout of electrically evoked maximal-intensity contractions (MICs). Our dataset provides the first comprehensive map of the MIC-regulated phosphoproteome. Using unbiased bioinformatics approaches, we demonstrate that our dataset leads to the identification of many well-known MIC-regulated signalling pathways, as well as to a plethora of novel MIC-regulated events. We expect that our dataset will serve as a fundamentally important resource for muscle biologists, and help to lay the foundation for entirely new hypotheses in the field. ABSTRACT The maintenance of skeletal muscle mass is essential for health and quality of life. It is well recognized that maximal-intensity contractions, such as those which occur during resistance exercise, promote an increase in muscle mass. Yet, the molecules that sense the mechanical information and convert it into the signalling events (e.g. phosphorylation) that drive the increase in muscle mass remain undefined. Here we describe a phosphoproteomics workflow to examine the effects of electrically evoked maximal-intensity contractions (MICs) on protein phosphorylation in mouse skeletal muscle. While a preliminary phosphoproteomics experiment successfully identified a number of MIC-regulated phosphorylation events, a large proportion of these identifications were present on highly abundant myofibrillar proteins. We subsequently incorporated a centrifugation-based fractionation step to deplete the highly abundant myofibrillar proteins and performed a second phosphoproteomics experiment. In total, we identified 5983 unique phosphorylation sites of which 663 were found to be regulated by MIC. GO term enrichment, phosphorylation motif analyses, and kinase-substrate predictions indicated that the MIC-regulated phosphorylation sites were chiefly modified by mTOR, as well as multiple isoforms of the MAPKs and CAMKs. Moreover, a high proportion of the regulated phosphorylation sites were found on proteins that are associated with the Z-disc, with over 74% of the Z-disc proteins experiencing robust changes in phosphorylation. Finally, our analyses revealed that the phosphorylation state of two Z-disc kinases (striated muscle-specific serine/threonine protein kinase and obscurin) was dramatically altered by MIC, and we propose ways these kinases could play a fundamental role in skeletal muscle mechanotransduction.
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Affiliation(s)
- Gregory K. Potts
- Department of ChemistryUniversity of Wisconsin – MadisonMadisonWIUSA
- Genome Center of WisconsinUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Rachel M. McNally
- Department of Comparative BiosciencesUniversity of Wisconsin – MadisonMadisonWIUSA
- School of Veterinary MedicineUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Rocky Blanco
- Department of Comparative BiosciencesUniversity of Wisconsin – MadisonMadisonWIUSA
- School of Veterinary MedicineUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Jae‐Sung You
- Department of Comparative BiosciencesUniversity of Wisconsin – MadisonMadisonWIUSA
- School of Veterinary MedicineUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Alexander S. Hebert
- Genome Center of WisconsinUniversity of Wisconsin – MadisonMadisonWIUSA
- Department of Biomolecular ChemistryUniversity of Wisconsin – MadisonMadisonWIUSA
| | | | - Joshua J. Coon
- Department of ChemistryUniversity of Wisconsin – MadisonMadisonWIUSA
- Genome Center of WisconsinUniversity of Wisconsin – MadisonMadisonWIUSA
- Department of Biomolecular ChemistryUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Troy A. Hornberger
- Department of Comparative BiosciencesUniversity of Wisconsin – MadisonMadisonWIUSA
- School of Veterinary MedicineUniversity of Wisconsin – MadisonMadisonWIUSA
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Influence of Resistance Training on Neuromuscular Function and Physical Capacity in ALS Patients. JOURNAL OF NEURODEGENERATIVE DISEASES 2017; 2017:1436519. [PMID: 28596929 PMCID: PMC5449732 DOI: 10.1155/2017/1436519] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Accepted: 04/24/2017] [Indexed: 12/14/2022]
Abstract
Objectives The present study aimed to explore the effect of resistance training in patients with amyotrophic lateral sclerosis (ALS), a disease characterized by progressive motor neuron loss and muscle weakness. Materials and Methods Following a 12-week “lead-in” control period, a population of ALS patients from Funen, Denmark, completed a 12-week resistance training program consisting of 2-3 sessions/week. Neuromuscular function (strength and power) and voluntary muscle activation (superimposed twitch technique) were evaluated before and after both control and training periods. Physical capacity tests (chair rise and timed up and go), the revised ALS functional rating scale (ALSFRS-R) scores, and muscle cross sectional area (histology) were also assessed. Results Of twelve ALS patients assessed for eligibility, six were included and five completed the study. Training did not significantly affect the ALSFRS-R score, and loss of neuromuscular function (strength and power) increased following the training period. However, an improved functionality (chair rise) and an increase in greatly hypertrophied type II fibres combined with an increase in atrophied fibres following the training period compared to the control period were observed. Conclusion In this small study, the present form of resistance training was unable to attenuate progressive loss of neuromuscular function in ALS, despite some changes in physical capacity and morphology.
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Intramuscular Anabolic Signaling and Endocrine Response Following Resistance Exercise: Implications for Muscle Hypertrophy. Sports Med 2017; 46:671-85. [PMID: 26666743 DOI: 10.1007/s40279-015-0450-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Maintaining skeletal muscle mass and function is critical for disease prevention, mobility and quality of life, and whole-body metabolism. Resistance exercise is known to be a major regulator for promoting muscle protein synthesis and muscle mass accretion. Manipulation of exercise intensity, volume, and rest elicit specific muscular adaptations that can maximize the magnitude of muscle growth. The stimulus of muscle contraction that occurs during differing intensities of resistance exercise results in varying biochemical responses regulating the rate of protein synthesis, known as mechanotransduction. At the cellular level, skeletal muscle adaptation appears to be the result of the cumulative effects of transient changes in gene expression following acute bouts of exercise. Thus, maximizing the resistance exercise-induced anabolic response produces the greatest potential for hypertrophic adaptation with training. The mechanisms involved in converting mechanical signals into the molecular events that control muscle growth are not completely understood; however, skeletal muscle protein synthesis appears to be regulated by the multi-protein phosphorylation cascade, mTORC1 (mammalian/mechanistic target of rapamycin complex 1). The purpose of this review is to examine the physiological response to resistance exercise, with particular emphasis on the endocrine response and intramuscular anabolic signaling through mTORC1. It appears that resistance exercise protocols that maximize muscle fiber recruitment, time-under-tension, and metabolic stress will contribute to maximizing intramuscular anabolic signaling; however, the resistance exercise parameters for maximizing the anabolic response remain unclear.
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Acute low-intensity cycling with blood-flow restriction has no effect on metabolic signaling in human skeletal muscle compared to traditional exercise. Eur J Appl Physiol 2017; 117:345-358. [DOI: 10.1007/s00421-016-3530-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2016] [Accepted: 12/29/2016] [Indexed: 10/20/2022]
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Schoenfeld BJ, Aragon A, Wilborn C, Urbina SL, Hayward SE, Krieger J. Pre- versus post-exercise protein intake has similar effects on muscular adaptations. PeerJ 2017; 5:e2825. [PMID: 28070459 PMCID: PMC5214805 DOI: 10.7717/peerj.2825] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 11/22/2016] [Indexed: 11/26/2022] Open
Abstract
The purpose of this study was to test the anabolic window theory by investigating muscle strength, hypertrophy, and body composition changes in response to an equal dose of protein consumed either immediately pre- versus post-resistance training (RT) in trained men. Subjects were 21 resistance-trained men (>1 year RT experience) recruited from a university population. After baseline testing, participants were randomly assigned to 1 of 2 experimental groups: a group that consumed a supplement containing 25 g protein and 1 g carbohydrate immediately prior to exercise (PRE-SUPP) (n = 9) or a group that consumed the same supplement immediately post-exercise (POST-SUPP) (n = 12). The RT protocol consisted of three weekly sessions performed on non-consecutive days for 10 weeks. A total-body routine was employed with three sets of 8–12 repetitions for each exercise. Results showed that pre- and post-workout protein consumption had similar effects on all measures studied (p > 0.05). These findings refute the contention of a narrow post-exercise anabolic window to maximize the muscular response and instead lends support to the theory that the interval for protein intake may be as wide as several hours or perhaps more after a training bout depending on when the pre-workout meal was consumed.
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Affiliation(s)
- Brad Jon Schoenfeld
- Department of Health Sciences, Herbert H. Lehman College, City University of New York , Bronx , NY , United States
| | - Alan Aragon
- Department of Nutrition, California State University , Northridge , CA , United States
| | - Colin Wilborn
- Graduate School and Research, University of Mary Hardin Baylor , Belton , TX , United States
| | - Stacie L Urbina
- Graduate School and Research, University of Mary Hardin Baylor , Belton , TX , United States
| | - Sara E Hayward
- Graduate School and Research, University of Mary Hardin Baylor , Belton , TX , United States
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Gonzalez AM. Acute Anabolic Response and Muscular Adaptation After Hypertrophy-Style and Strength-Style Resistance Exercise. J Strength Cond Res 2016; 30:2959-64. [DOI: 10.1519/jsc.0000000000001378] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Camera DM, Smiles WJ, Hawley JA. Exercise-induced skeletal muscle signaling pathways and human athletic performance. Free Radic Biol Med 2016; 98:131-143. [PMID: 26876650 DOI: 10.1016/j.freeradbiomed.2016.02.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 01/28/2016] [Accepted: 02/03/2016] [Indexed: 12/18/2022]
Abstract
Skeletal muscle is a highly malleable tissue capable of altering its phenotype in response to external stimuli including exercise. This response is determined by the mode, (endurance- versus resistance-based), volume, intensity and frequency of exercise performed with the magnitude of this response-adaptation the basis for enhanced physical work capacity. However, training-induced adaptations in skeletal muscle are variable and unpredictable between individuals. With the recent application of molecular techniques to exercise biology, there has been a greater understanding of the multiplicity and complexity of cellular networks involved in exercise responses. This review summarizes the molecular and cellular events mediating adaptation processes in skeletal muscle in response to exercise. We discuss established and novel cell signaling proteins mediating key physiological responses associated with enhanced exercise performance and the capacity for reactive oxygen and nitrogen species to modulate training adaptation responses. We also examine the molecular bases underpinning heterogeneous responses to resistance and endurance exercise and the dissociation between molecular 'markers' of training adaptation and subsequent exercise performance.
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Affiliation(s)
- Donny M Camera
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia
| | - William J Smiles
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia
| | - John A Hawley
- Centre for Exercise and Nutrition, Mary MacKillop Institute for Health Research, Australian Catholic University, Melbourne, Vic. 3065, Australia; Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool L3 3AF, United Kingdom.
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Exercise Promotes Healthy Aging of Skeletal Muscle. Cell Metab 2016; 23:1034-1047. [PMID: 27304505 PMCID: PMC5045036 DOI: 10.1016/j.cmet.2016.05.007] [Citation(s) in RCA: 292] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 05/18/2016] [Accepted: 05/24/2016] [Indexed: 02/08/2023]
Abstract
Primary aging is the progressive and inevitable process of bodily deterioration during adulthood. In skeletal muscle, primary aging causes defective mitochondrial energetics and reduced muscle mass. Secondary aging refers to additional deleterious structural and functional age-related changes caused by diseases and lifestyle factors. Secondary aging can exacerbate deficits in mitochondrial function and muscle mass, concomitant with the development of skeletal muscle insulin resistance. Exercise opposes deleterious effects of secondary aging by preventing the decline in mitochondrial respiration, mitigating aging-related loss of muscle mass and enhancing insulin sensitivity. This review focuses on mechanisms by which exercise promotes "healthy aging" by inducing modifications in skeletal muscle.
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Stec MJ, Kelly NA, Many GM, Windham ST, Tuggle SC, Bamman MM. Ribosome biogenesis may augment resistance training-induced myofiber hypertrophy and is required for myotube growth in vitro. Am J Physiol Endocrinol Metab 2016; 310:E652-E661. [PMID: 26860985 PMCID: PMC4835943 DOI: 10.1152/ajpendo.00486.2015] [Citation(s) in RCA: 100] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/03/2016] [Indexed: 12/22/2022]
Abstract
Resistance exercise training (RT) is the most effective method for increasing skeletal muscle mass in older adults; however, the amount of RT-induced muscle growth is highly variable between individuals. Recent evidence from our laboratory and others suggests ribosome biogenesis may be an important factor regulating RT-induced hypertrophy, and we hypothesized that the extent of hypertrophy is at least partly regulated by the amount of RT-induced ribosome biogenesis. To examine this, 42 older adults underwent 4 wk of RT aimed at inducing hypertrophy of the knee extensors (e.g., 2 sets of squat, leg press, and knee extension, 10-12 repetition maximums, 3 days/wk), and vastus lateralis muscle biopsies were performed pre- and post-RT. Post hoc K-means cluster analysis revealed distinct differences in type II myofiber hypertrophy among subjects. The percent change in type II myofiber size in nonresponders (Non; n = 17) was -7%, moderate responders (Mod; n = 19) +22%, and extreme responders (Xtr; n = 6) +83%. Total muscle RNA increased only in Mod (+9%, P < 0.08) and Xtr (+26%, P < 0.01), and only Xtr increased rRNA content (+40%, P < 0.05) and myonuclei/type II fiber (+32%, P < 0.01). Additionally, Mod and Xtr had a greater increase in c-Myc protein levels compared with Non (e.g., approximately +350 and +250% vs. +50%, respectively, P < 0.05). In vitro studies showed that growth factor-induced human myotube hypertrophy is abolished when rRNA synthesis is knocked down using the Pol I-specific inhibitor CX-5461. Overall, these data implicate ribosome biogenesis as a key process regulating the extent of RT-induced myofiber hypertrophy in older adults.
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Affiliation(s)
- Michael J Stec
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Neil A Kelly
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Gina M Many
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Samuel T Windham
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Department of Surgery, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - S Craig Tuggle
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
| | - Marcas M Bamman
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama;
- UAB Center for Exercise Medicine, University of Alabama at Birmingham, Birmingham, Alabama; and
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Birmingham, Alabama
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