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Battey E, Levy Y, Pollock RD, Pugh JN, Close GL, Kalakoutis M, Lazarus NR, Harridge SDR, Ochala J, Stroud MJ. Muscle fibre size and myonuclear positioning in trained and aged humans. Exp Physiol 2024; 109:549-561. [PMID: 38461483 PMCID: PMC10988734 DOI: 10.1113/ep091567] [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: 10/04/2023] [Accepted: 02/05/2024] [Indexed: 03/12/2024]
Abstract
Changes in myonuclear architecture and positioning are associated with exercise adaptations and ageing. However, data on the positioning and number of myonuclei following exercise are inconsistent. Additionally, whether myonuclear domains (MNDs; i.e., the theoretical volume of cytoplasm within which a myonucleus is responsible for transcribing DNA) and myonuclear positioning are altered with age remains unclear. The aim of this investigation was to investigate relationships between age and activity status and myonuclear domains and positioning. Vastus lateralis muscle biopsies from younger endurance-trained (YT) and older endurance-trained (OT) individuals were compared with age-matched untrained counterparts (YU and OU; OU samples were acquired during surgical operation). Serial, optical z-slices were acquired throughout isolated muscle fibres and analysed to give three-dimensional coordinates for myonuclei and muscle fibre dimensions. The mean cross-sectional area (CSA) of muscle fibres from OU individuals was 33%-53% smaller compared with the other groups. The number of nuclei relative to fibre CSA was 90% greater in OU compared with YU muscle fibres. Additionally, scaling of MND volume with fibre size was altered in older untrained individuals. The myonuclear arrangement, in contrast, was similar across groups. Fibre CSA and most myonuclear parameters were significantly associated with age in untrained individuals, but not in trained individuals. These data indicate that regular endurance exercise throughout the lifespan might better preserve the size of muscle fibres in older age and maintain the relationship between fibre size and MND volumes. Inactivity, however, might result in reduced muscle fibre size and altered myonuclear parameters.
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Affiliation(s)
- Edmund Battey
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and SciencesKing's College LondonLondonUK
- Department of Biomedical Sciences, Faculty of Medical and Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Yotam Levy
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Ross D. Pollock
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Jamie N. Pugh
- School of Sport and Exercise Sciences, Tom Reilly Building, Byrom StreetLiverpool John Moores UniversityLiverpoolUK
| | - Graeme L. Close
- School of Sport and Exercise Sciences, Tom Reilly Building, Byrom StreetLiverpool John Moores UniversityLiverpoolUK
| | - Michaeljohn Kalakoutis
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- Randall Centre for Cell and Molecular Biophysics, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Norman R. Lazarus
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Stephen D. R. Harridge
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
| | - Julien Ochala
- Centre for Human & Applied Physiological Sciences, Faculty of Life Sciences & MedicineKing's College LondonLondonUK
- Department of Biomedical Sciences, Faculty of Medical and Health SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Matthew J. Stroud
- British Heart Foundation Centre of Research Excellence, School of Cardiovascular Medicine and SciencesKing's College LondonLondonUK
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Skoupá K, Bátik A, Št'astný K, Sládek Z. Structural Changes in the Skeletal Muscle of Pigs after Long-Term Administration of Testosterone, Nandrolone and a Combination of the Two. Animals (Basel) 2023; 13:2141. [PMID: 37443939 DOI: 10.3390/ani13132141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/15/2023] Open
Abstract
Anabolic steroid hormones (AASs) are used in most countries of the world to accelerate the growth of animals, increase the volume of their muscles and thereby increase meat production. However, there is a strict ban on the use of AASs in the fattening of all animals in all countries of the European Union, and there must therefore be effective methods of detection and control of these substances. Methods based on chromatography and mass spectrometry may no longer be completely effective when faced with new synthetic steroids of unknown chemical structures and low concentrations. Therefore, there is an effort to develop new methods of AAS detection, based primarily on the monitoring of biological changes at the level of gene expression or changes in metabolism or structure at the cellular level. More detailed knowledge of the mechanisms of action of AASs on tissues is essential for these methods, and histological changes are one of them. In this study, we report histological changes in muscle structure after AAS application, specifically in the size of muscle fibers, the amount of endomysium and the number of nuclei and satellite cells in muscle fibers. A pig model was also intentionally used for the study, as no such study has been carried out on this species, and at the same time, pork is one of the most consumed meats across Europe. The results of histology and fluorescent antibody labeling showed that AASs increased the diameter and surface area of muscle fibers and also significantly increased the number of satellite cells on the fiber surface. The evident correlations between the number of satellite cells, all nuclei and the diameters of muscle fibers between some experimental groups provide evidence that the selected histological parameters could be additional detection mechanisms for screening a large number of samples and indicate the possibility of the presence of AASs in pork meat in the future.
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Affiliation(s)
- Kristýna Skoupá
- Department of Animal Morphology, Physiology and Genetics, Faculty of AgrSciences, Mendel University in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
| | - Andrej Bátik
- Department of Animal Morphology, Physiology and Genetics, Faculty of AgrSciences, Mendel University in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
| | - Kamil Št'astný
- Veterinary Research Institute in Brno, Hudcova 296/70, 621 00 Brno, Czech Republic
| | - Zbyšek Sládek
- Department of Animal Morphology, Physiology and Genetics, Faculty of AgrSciences, Mendel University in Brno, Zemedelska 1, 613 00 Brno, Czech Republic
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Machek SB, Cardaci TD, Wilburn DT, Willoughby DS. Considerations, possible contraindications, and potential mechanisms for deleterious effect in recreational and athletic use of selective androgen receptor modulators (SARMs) in lieu of anabolic androgenic steroids: A narrative review. Steroids 2020; 164:108753. [PMID: 33148520 DOI: 10.1016/j.steroids.2020.108753] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 10/07/2020] [Accepted: 10/17/2020] [Indexed: 12/12/2022]
Abstract
Anabolic androgenic steroids (AAS) are testosterone and testosterone-derivative compounds sporadically employed by athletes and increasingly used recreationally to acquire a competitive edge or improve body composition. Nevertheless, users are subject to undesired side effects majorly associated with tissue-specific androgen receptor (AR) binding-mediated actions. More recently, selective AR modulators (SARMs) have gained popularity towards delivering androgen-associated anabolic actions with hopes of minimal androgenic effects. While several SARMs are in preclinical and clinical phases intended for demographics subject to hypogonadism, muscle wasting, and osteoporosis, several athletic organizations and drug testing affiliates have realized the increasingly widespread use of SARMs amongst competitors and have subsequently banned their use. Furthermore, recreational users are haphazardly acquiring these compounds from the internet and consuming doses several times greater than empirically reported. Unfortunately, online sources are rife with potential contamination, despite a prevailing public opinion suggesting SARMs are innocuous AAS alternatives. Considering each agent has a broad range of supporting evidence in both human and non-human models, it is important to comprehensively evaluate the current literature on commercially available SARMs to gain better understanding of their efficacy and if they can truly be considered a safer AAS alternative. Therefore, the purpose of this review is to discuss the current evidence regarding AAS and SARM mechanisms of action, demonstrate the efficacy of several prominent SARMs in a variety of scientific trials, and theorize on the wide-ranging contraindications and potential deleterious effects, as well as potential future directions regarding acute and chronic SARM use across a broad range of demographics.
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Affiliation(s)
- Steven B Machek
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA
| | - Thomas D Cardaci
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA; Department of Exercise Science, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA
| | - Dylan T Wilburn
- Exercise & Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation. Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA
| | - Darryn S Willoughby
- Mayborn College of Health Sciences, School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA.
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Machek SB, Hwang PS, Cardaci TD, Wilburn DT, Bagley JR, Blake DT, Galpin AJ, Willoughby DS. Myosin Heavy Chain Composition, Creatine Analogues, and the Relationship of Muscle Creatine Content and Fast-Twitch Proportion to Wilks Coefficient in Powerlifters. J Strength Cond Res 2020; 34:3022-3030. [PMID: 33105350 DOI: 10.1519/jsc.0000000000003804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Machek, SB, Hwang, PS, Cardaci, TD, Wilburn, DT, Bagley, JR, Blake, DT, Galpin, AJ, and Willoughby, DS. Myosin heavy chain composition, creatine analogues, and the relationship of muscle creatine content and fast-twitch proportion to Wilks coefficient in powerlifters. J Strength Cond Res 34(11): 3022-3030, 2020-Little data exist on powerlifting-specific skeletal muscle adaptations, and none elucidate sex differences in powerlifters. Powerlifters tend to display higher fast-twitch fiber content and phosphagen system dependence. Nevertheless, it is unknown whether fast-twitch fiber or muscle creatine content are predictive of competitive powerlifting performance (via Wilks coefficient). Twelve actively competing powerlifters (PL; n = 6M/6F; age = 21.3 ± 1.0; 3.0 ± 1.8 year competing; 7.3 ± 6.6 meets attended) and 10 sedentary controls (CON; n = 5M/5F; age = 19.4 ± 2.0 year) underwent vastus lateralis muscle biopsies and venipuncture to compare the myosin heavy chain (MHC) fiber type and creatine analogue profiles between groups of both sexes, and determine whether MHC IIa and muscle total creatine (MTC) composition predict powerlifting performance. Samples were analyzed for specific MHC isoform (I, IIa, and IIx) content via mixed homogenate SDS-PAGE, and creatine analogues (MTC, muscle creatine transporter [SLC6A8], serum total creatine [STC], and serum creatinine [CRT]). Furthermore, MHC IIa and MTC content were compared with Wilks coefficient using Pearson correlation coefficients. Male PL MHC content was 50 ± 6% I, 45 ± 6% IIa, and 5 ± 11% IIx, versus 46 ± 6% I, 53 ± 6 IIa, and 0% IIx in female PL. Conversely, male CON MHC content was 33 ± 5% I, 38 ± 7% IIa, and 30 ± 8% IIx, vs. 35 ± 9% I, 44 ± 8% IIa, and 21 ± 17% IIx in female CON. Muscle total creatine, SLC6A8, STC, and CRT did not significantly differ between groups nor sexes. Finally, neither MHC IIa content (r = -0.288; p = 0.364) nor MTC (r = 0.488; p = 0.108) significantly predicted Wilks coefficient, suggesting these characteristics alone do not determine powerlifting skill variation.
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Affiliation(s)
- Steven B Machek
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas
| | - Paul S Hwang
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas
| | - Thomas D Cardaci
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas
| | - Dylan T Wilburn
- Exercise and Biochemical Nutrition Laboratory, Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, Texas
| | - James R Bagley
- Muscle Physiology Laboratory, Department of Kinesiology, College of Health and Social Sciences, San Francisco State University, San Francisco, California
| | - Daniel T Blake
- Department of Kinesiology, Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California; and
| | - Andrew J Galpin
- Department of Kinesiology, Biochemistry and Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton, California; and
| | - Darryn S Willoughby
- Mayborn College of Health Sciences, School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, Texas
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