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Edman S, Horwath O, Van der Stede T, Blackwood SJ, Moberg I, Strömlind H, Nordström F, Ekblom M, Katz A, Apró W, Moberg M. Pro-Brain-Derived Neurotrophic Factor (BDNF), but Not Mature BDNF, Is Expressed in Human Skeletal Muscle: Implications for Exercise-Induced Neuroplasticity. Function (Oxf) 2024; 5:zqae005. [PMID: 38706964 PMCID: PMC11065112 DOI: 10.1093/function/zqae005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 01/24/2024] [Indexed: 05/07/2024] Open
Abstract
Exercise promotes brain plasticity partly by stimulating increases in mature brain-derived neurotrophic factor (mBDNF), but the role of the pro-BDNF isoform in the regulation of BDNF metabolism in humans is unknown. We quantified the expression of pro-BDNF and mBDNF in human skeletal muscle and plasma at rest, after acute exercise (+/- lactate infusion), and after fasting. Pro-BDNF and mBDNF were analyzed with immunoblotting, enzyme-linked immunosorbent assay, immunohistochemistry, and quantitative polymerase chain reaction. Pro-BDNF was consistently and clearly detected in skeletal muscle (40-250 pg mg-1 dry muscle), whereas mBDNF was not. All methods showed a 4-fold greater pro-BDNF expression in type I muscle fibers compared to type II fibers. Exercise resulted in elevated plasma levels of mBDNF (55%) and pro-BDNF (20%), as well as muscle levels of pro-BDNF (∼10%, all P < 0.05). Lactate infusion during exercise induced a significantly greater increase in plasma mBDNF (115%, P < 0.05) compared to control (saline infusion), with no effect on pro-BDNF levels in plasma or muscle. A 3-day fast resulted in a small increase in plasma pro-BDNF (∼10%, P < 0.05), with no effect on mBDNF. Pro-BDNF is highly expressed in human skeletal muscle, particularly in type I fibers, and is increased after exercise. While exercising with higher lactate augmented levels of plasma mBDNF, exercise-mediated increases in circulating mBDNF likely derive partly from release and cleavage of pro-BDNF from skeletal muscle, and partly from neural and other tissues. These findings have implications for preclinical and clinical work related to a wide range of neurological disorders such as Alzheimer's, clinical depression, and amyotrophic lateral sclerosis.
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Affiliation(s)
- Sebastian Edman
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
- Department of Women’s and Children’s Health, Karolinska Institute, Stockholm 171 77, Sweden
| | - Oscar Horwath
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - Thibaux Van der Stede
- Department of Movement and Sport Sciences, Ghent University, Ghent 9000, Belgium
- The August Krogh Section for Human Physiology, Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen 1172, Denmark
| | - Sarah Joan Blackwood
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - Isabel Moberg
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - Henrik Strömlind
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - Fabian Nordström
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - Maria Ekblom
- Department of Physical Activity and Health, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
- Department of Neuroscience, Karolinska Institute, Stockholm 171 77, Sweden
| | - Abram Katz
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
| | - William Apró
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm 171 77, Sweden
| | - Marcus Moberg
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm 114 33, Sweden
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm 171 77, Sweden
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Edman S, Horwath O, Apró W. THRIFTY-A High-throughput Single Muscle Fiber Typing Method Based on Immunofluorescence Detection. Bio Protoc 2023; 13:e4678. [PMID: 37251094 PMCID: PMC10213079 DOI: 10.21769/bioprotoc.4678] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/07/2023] [Accepted: 03/22/2023] [Indexed: 05/31/2023] Open
Abstract
Skeletal muscle consists of a mixture of fiber types with different functional and metabolic characteristics. The relative composition of these muscle fiber types has implications for muscle performance, whole-body metabolism, and health. However, analyses of muscle samples in a fiber type-dependent manner are very time consuming. Therefore, these are often neglected in favor of more time-efficient analyses on mixed muscle samples. Methods such as western blot and myosin heavy chain separation by SDS-PAGE have previously been utilized to fiber type-isolated muscle fibers. More recently, the introduction of the dot blot method significantly increased the speed of fiber typing. However, despite recent advancements, none of the current methodologies are feasible for large-scale investigations because of their time requirements. Here, we present the protocol for a new method, which we have named THRIFTY (high-THRoughput Immunofluorescence Fiber TYping), that enables rapid fiber type identification using antibodies towards the different myosin heavy chain (MyHC) isoforms of fast and slow twitch muscle fibers. First, a short segment (<1 mm) is cut off from isolated muscle fibers and mounted on a customized gridded microscope slide holding up to 200 fiber segments. Second, the fiber segments attached to the microscope slide are stained with MyHC-specific antibodies and then visualized using a fluorescence microscope. Lastly, the remaining pieces of the fibers can either be collected individually or pooled together with fibers of the same type for subsequent analyses. The THRIFTY protocol is approximately three times as fast as the dot blot method, which enables not only time-sensitive assays to be performed but also increases the feasibility to conduct large-scale investigations into fiber type specific physiology. Graphical Overview Graphical overview of the THRIFTY workflow. Cut off a small segment (0.5 mm) of an individually dissected muscle fiber and mount it onto the customized microscope slide containing a printed grid system. Using a Hamilton syringe, fixate the fiber segment by applying a small droplet of distilled water on the segment and let it fully dry (1A). The remaining large segment of the fiber should be placed in the corresponding square on a black A4 paper (1B). Once the microscope slide has been fully mounted with fiber segments, submerge the slide in a polypropylene slide mailer (illustrated as a Coplin jar in the figure) containing acetone to permeabilize the fiber segments. Thereafter, incubate the slide with primary antibodies targeting MyHC-I and MyHC-II. Following washes in PBS solution, incubate the slides with fluorescently labeled secondary antibodies, wash again, and mount with a cover glass and antifade reagent (2). Identification of fiber type can be performed using a digital fluorescence microscope (3), whereafter the remaining pieces of the fiber segments (large) are pooled together according to their fiber type or individually collected for experiments on single fibers (4). Image modified from Horwath et al. (2022).
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Affiliation(s)
- Sebastian Edman
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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Horwath O, Nordström F, von Walden F, Apró W, Moberg M. Acute hypoxia attenuates resistance exercise-induced ribosome signaling but does not impact satellite cell pool expansion in human skeletal muscle. FASEB J 2023; 37:e22811. [PMID: 36786723 DOI: 10.1096/fj.202202065rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 01/25/2023] [Accepted: 01/27/2023] [Indexed: 02/15/2023]
Abstract
Cumulative evidence supports the hypothesis that hypoxia acts as a regulator of muscle mass. However, the underlying molecular mechanisms remain incompletely understood, particularly in human muscle. Here we examined the effect of hypoxia on signaling pathways related to ribosome biogenesis and myogenic activity following an acute bout of resistance exercise. We also investigated whether hypoxia influenced the satellite cell response to resistance exercise. Employing a randomized, crossover design, eight men performed resistance exercise in normoxia (FiO2 21%) or normobaric hypoxia (FiO2 12%). Muscle biopsies were collected in a time-course manner (before, 0, 90, 180 min and 24 h after exercise) and were analyzed with respect to cell signaling, gene expression and satellite cell content using immunoblotting, RT-qPCR and immunofluorescence, respectively. In normoxia, resistance exercise increased the phosphorylation of RPS6, TIF-1A and UBF above resting levels. Hypoxia reduced the phosphorylation of these targets by ~37%, ~43% and ~ 67% throughout the recovery period, respectively (p < .05 vs. normoxia). Resistance exercise also increased 45 S pre-rRNA expression and mRNA expression of c-Myc, Pol I and TAF-1A above resting levels, but no differences were observed between conditions. Similarly, resistance exercise increased mRNA expression of myogenic regulatory factors throughout the recovery period and Pax7+ cells were elevated 24 h following exercise in mixed and type II muscle fibers, with no differences observed between normoxia and hypoxia. In conclusion, acute hypoxia attenuates ribosome signaling, but does not impact satellite cell pool expansion and myogenic gene expression following a bout of resistance exercise in human skeletal muscle.
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Affiliation(s)
- Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Fabian Nordström
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Ferdinand von Walden
- Division of Pediatric Neurology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Solna, Sweden
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institutet, Solna, Sweden
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Blackwood SJ, Horwath O, Moberg M, Pontén M, Apró W, Ekblom MM, Larsen FJ, Katz A. Insulin resistance after a 3-day fast is associated with an increased capacity of skeletal muscle to oxidize lipids. Am J Physiol Endocrinol Metab 2023; 324:E390-E401. [PMID: 36791323 DOI: 10.1152/ajpendo.00317.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
There is a debate on whether lipid-mediated insulin resistance derives from an increased or decreased capacity of muscle to oxidize fats. Here we examine the involvement of muscle fiber composition in the metabolic responses to a 3-day fast (starvation, which results in increases in plasma lipids and insulin resistance) in two groups of healthy young subjects: 1, area occupied by type I fibers = 61.0 ± 11.8%; 2, type I area = 36.0 ± 4.9% (P<0.001). Muscle biopsies and intravenous glucose tolerance tests were performed after an overnight fast and after starvation. Biopsies were analyzed for muscle fiber composition and mitochondrial respiration. Indices of glucose tolerance and insulin sensitivity were determined. Glucose tolerance was similar in both groups after an overnight fast and deteriorated to a similar degree in both groups after starvation. In contrast, whole-body insulin sensitivity decreased markedly after starvation in group 1 (P<0.01), whereas the decrease in group 2 was substantially smaller (P=0.06). Non-esterified fatty acids and β-hydroxybutyrate levels in plasma after an overnight fast were similar between groups and increased markedly and comparably in both groups after starvation, demonstrating similar degrees of lipid load. The capacity of permeabilized muscle fibers to oxidize lipids was significantly higher in group 1 vs. 2, whereas there was no significant difference in pyruvate oxidation between groups. The data demonstrate that loss of whole-body insulin sensitivity after short-term starvation is a function of muscle fiber composition and is associated with an elevated rather than a diminished capacity of muscle to oxidize lipids.
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Affiliation(s)
- Sarah J Blackwood
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Oscar Horwath
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Marcus Moberg
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Marjan Pontén
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Maria M Ekblom
- Department of Physical Activity and Health, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Filip J Larsen
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Abram Katz
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
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Horwath O, Edman S, Andersson A, Larsen FJ, Apró W. THRIFTY: a novel high-throughput method for rapid fibre type identification of isolated skeletal muscle fibres. J Physiol 2022; 600:4421-4438. [PMID: 36069036 PMCID: PMC9825974 DOI: 10.1113/jp282959] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 08/25/2022] [Indexed: 01/11/2023] Open
Abstract
Fibre type-specific analyses are required for broader understanding of muscle physiology, but such analyses are difficult to conduct due to the extreme time requirements of dissecting and fibre typing individual fibres. Investigations are often confined to a small number of fibres from few participants with low representativeness of the entire fibre population and the participant population. To increase the feasibility of conducting large-scale fibre type-specific studies, a valid and rapid method for high-throughput fibre typing of individually dissected fibres was developed and named THRIFTY (for high-THRoughput Immunofluorescence Fibre TYping). Employing THRIFTY, 400 fibre segments were fixed onto microscope slides with a pre-printed coordinated grid system, probed with antibodies against myosin heavy chain (MyHC)-I and MyHC-II and classified using a fluorescence microscope. The validity and speed of THRIFTY was compared to a previously validated protocol (dot blot) on a fibre-to-fibre basis. Fibre pool purity was evaluated using 'gold standard' SDS-PAGE and silver staining. A modified THRIFTY-protocol using fluorescence western blot equipment was also validated. THRIFTY displayed excellent agreement with the dot blot protocol, κ = 0.955 (95% CI: 0.928, 0.982), P < 0.001. Both the original and modified THRIFTY protocols generated type I and type II fibre pools of absolute purity. Using THRIFTY, 400 fibres were typed just under 11 h, which was approximately 3 times faster than dot blot. THRIFTY is a novel and valid method with high versatility for very rapid fibre typing of individual fibres. THRIFTY can therefore facilitate the generation of large fibre pools for more extensive mechanistic studies into skeletal muscle physiology. KEY POINTS: Skeletal muscle is composed of different fibre types, each with distinct physiological properties. To fully understand how skeletal muscle adapts to external cues such as exercise, nutrition and ageing, fibre type-specific investigations are required. Such investigations are very difficult to conduct due to the extreme time requirements related to classifying individually isolated muscle fibres. To bypass this issue, we have developed a rapid and reliable method named THRIFTY which is cheap as well as versatile and which can easily be implemented in most laboratories. THRIFTY increases the feasibility of conducting larger fibre type-specific studies and enables time-sensitive assays where measurements need to be carried out in close connection with tissue sampling. By using THRIFTY, new insights into fibre type-specific muscle physiology can be gained which may have broad implications in health and disease.
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Affiliation(s)
- Oscar Horwath
- Department of PhysiologyNutrition and BiomechanicsÅstrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
| | - Sebastian Edman
- Department of PhysiologyNutrition and BiomechanicsÅstrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
| | - Alva Andersson
- Department of PhysiologyNutrition and BiomechanicsÅstrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
| | - Filip J. Larsen
- Department of PhysiologyNutrition and BiomechanicsÅstrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden
| | - William Apró
- Department of PhysiologyNutrition and BiomechanicsÅstrand LaboratorySwedish School of Sport and Health SciencesStockholmSweden,Department of Clinical ScienceIntervention and TechnologyKarolinska InstitutetStockholmSweden
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Edman S, Horwath O, Andersson A, Apró W. THRIFTY; A Novel Method For Rapid Fiber Type Identification Of Isolated Skeletal Muscle Fibers. Med Sci Sports Exerc 2022. [DOI: 10.1249/01.mss.0000876416.24394.9e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blackwood SJ, Horwath O, Moberg M, Pontén M, Apró W, Ekblom MM, Larsen FJ, Katz A. Extreme Variations in Muscle Fiber Composition Enable Detection of Insulin Resistance and Excessive Insulin Secretion. J Clin Endocrinol Metab 2022; 107:e2729-e2737. [PMID: 35405014 DOI: 10.1210/clinem/dgac221] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Indexed: 12/16/2022]
Abstract
CONTEXT Muscle fiber composition is associated with peripheral insulin action. OBJECTIVE We investigated whether extreme differences in muscle fiber composition are associated with alterations in peripheral insulin action and secretion in young, healthy subjects who exhibit normal fasting glycemia and insulinemia. METHODS Relaxation time following a tetanic contraction was used to identify subjects with a high or low expression of type I muscle fibers: group 1 (n = 11), area occupied by type I muscle fibers = 61.0 ± 11.8%, and group 2 (n = 8), type I area = 36.0 ± 4.9% (P < 0.001). Biopsies were obtained from the vastus lateralis muscle and analyzed for mitochondrial respiration on permeabilized fibers, muscle fiber composition, and capillary density. An intravenous glucose tolerance test was performed and indices of glucose tolerance, insulin sensitivity, and secretion were determined. RESULTS Glucose tolerance was similar between groups, whereas whole-body insulin sensitivity was decreased by ~50% in group 2 vs group 1 (P = 0.019). First-phase insulin release (area under the insulin curve during 10 minutes after glucose infusion) was increased by almost 4-fold in group 2 vs group 1 (P = 0.01). Whole-body insulin sensitivity was correlated with percentage area occupied by type I fibers (r = 0.54; P = 0.018) and capillary density in muscle (r = 0.61; P = 0.005) but not with mitochondrial respiration. Insulin release was strongly related to percentage area occupied by type II fibers (r = 0.93; P < 0.001). CONCLUSIONS Assessment of muscle contractile function in young healthy subjects may prove useful in identifying individuals with insulin resistance and enhanced glucose-stimulated insulin secretion prior to onset of clinical manifestations.
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Affiliation(s)
- Sarah J Blackwood
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Oscar Horwath
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Marcus Moberg
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Marjan Pontén
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
| | - Maria M Ekblom
- Department of Physical Activity and Health, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Filip J Larsen
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Abram Katz
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
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Moberg M, Apró W, Horwath O, Hall G, Blackwood SJ, Katz A. Acute normobaric hypoxia blunts contraction-mediated mTORC1- and JNK-signaling in human skeletal muscle. Acta Physiol (Oxf) 2022; 234:e13771. [PMID: 34984845 PMCID: PMC9285439 DOI: 10.1111/apha.13771] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 09/28/2021] [Accepted: 01/01/2022] [Indexed: 12/26/2022]
Abstract
Aim Hypoxia has been shown to reduce resistance exercise‐induced stimulation of protein synthesis and long‐term gains in muscle mass. However, the mechanism whereby hypoxia exerts its effect is not clear. Here, we examine the effect of acute hypoxia on the activity of several signalling pathways involved in the regulation of muscle growth following a bout of resistance exercise. Methods Eight men performed two sessions of leg resistance exercise in normoxia or hypoxia (12% O2) in a randomized crossover fashion. Muscle biopsies were obtained at rest and 0, 90,180 minutes after exercise. Muscle analyses included levels of signalling proteins and metabolites associated with energy turnover. Results Exercise during normoxia induced a 5‐10‐fold increase of S6K1Thr389 phosphorylation throughout the recovery period, but hypoxia blunted the increases by ~50%. Phosphorylation of JNKThr183/Tyr185 and the JNK target SMAD2Ser245/250/255 was increased by 30‐ to 40‐fold immediately after the exercise in normoxia, but hypoxia blocked almost 70% of the activation. Throughout recovery, phosphorylation of JNK and SMAD2 remained elevated following the exercise in normoxia, but the effect of hypoxia was lost at 90‐180 minutes post‐exercise. Hypoxia had no effect on exercise‐induced Hippo or autophagy signalling and ubiquitin‐proteasome related protein levels. Nor did hypoxia alter the changes induced by exercise in high‐energy phosphates, glucose 6‐P, lactate or phosphorylation of AMPK or ACC. Conclusion We conclude that acute severe hypoxia inhibits resistance exercise‐induced mTORC1‐ and JNK signalling in human skeletal muscle, effects that do not appear to be mediated by changes in the degree of metabolic stress in the muscle.
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Affiliation(s)
- Marcus Moberg
- Åstrand Laboratory Department of Physiology, Nutrition and Biomechanics Swedish School of Sport and Health Sciences Stockholm Sweden
- Department of Physiology and Pharmacology Karolinska Institute Stockholm Sweden
| | - William Apró
- Åstrand Laboratory Department of Physiology, Nutrition and Biomechanics Swedish School of Sport and Health Sciences Stockholm Sweden
- Department of Clinical Science, Intervention and Technology Karolinska Institute Stockholm Sweden
| | - Oscar Horwath
- Åstrand Laboratory Department of Physiology, Nutrition and Biomechanics Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Gerrit Hall
- Department of Biomedical Sciences Faculty of Health and Medical Sciences University of Copenhagen Copenhagen Denmark
- Clinical Metabolomics Core Facility, Clinical Biochemistry Rigshospitalet Copenhagen Denmark
| | - Sarah Joan Blackwood
- Åstrand Laboratory Department of Physiology, Nutrition and Biomechanics Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Abram Katz
- Åstrand Laboratory Department of Physiology, Nutrition and Biomechanics Swedish School of Sport and Health Sciences Stockholm Sweden
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Horwath O, Moberg M, Hirschberg AL, Ekblom B, Apró W. Molecular Regulators of Muscle Mass and Mitochondrial Remodeling Are Not Influenced by Testosterone Administration in Young Women. Front Endocrinol (Lausanne) 2022; 13:874748. [PMID: 35498440 PMCID: PMC9046720 DOI: 10.3389/fendo.2022.874748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 03/18/2022] [Indexed: 01/07/2023] Open
Abstract
Testosterone (T) administration has previously been shown to improve muscle size and oxidative capacity. However, the molecular mechanisms underlying these adaptations in human skeletal muscle remain to be determined. Here, we examined the effect of moderate-dose T administration on molecular regulators of muscle protein turnover and mitochondrial remodeling in muscle samples collected from young women. Forty-eight healthy, physically active, young women (28 ± 4 years) were assigned in a random double-blind fashion to receive either T (10 mg/day) or placebo for 10-weeks. Muscle biopsies collected before and after the intervention period were divided into sub-cellular fractions and total protein levels of molecular regulators of muscle protein turnover and mitochondrial remodeling were analyzed using Western blotting. T administration had no effect on androgen receptor or 5α-reductase levels, nor on proteins involved in the mTORC1-signaling pathway (mTOR, S6K1, eEF2 and RPS6). Neither did it affect the abundance of proteins associated with proteasomal protein degradation (MAFbx, MuRF-1 and UBR5) and autophagy-lysosomal degradation (AMPK, ULK1 and p62). T administration also had no effect on proteins in the mitochondria enriched fraction regulating mitophagy (Beclin, BNIP3, LC3B-I, LC3B-II and LC3B-II/I ratio) and morphology (Mitofilin), and it did not alter the expression of mitochondrial fission- (FIS1 and DRP1) or fusion factors (OPA1 and MFN2). In summary, these data indicate that improvements in muscle size and oxidative capacity in young women in response to moderate-dose T administration cannot be explained by alterations in total expression of molecular factors known to regulate muscle protein turnover or mitochondrial remodeling.
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Affiliation(s)
- Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
- *Correspondence: Oscar Horwath,
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Angelica Lindén Hirschberg
- Department of Women´s and Children´s Health, Division of Neonatology, Obstetrics and Gynaecology, Karolinska Institutet, Stockholm, Sweden
- Department of Gynaecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden
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Jonsson WO, Ponette J, Horwath O, Rydenstam T, Söderlund K, Ekblom B, Azzolini M, Ruas JL, Blomstrand E. Changes in plasma concentration of kynurenine following intake of branched-chain amino acids are not caused by alterations in muscle kynurenine metabolism. Am J Physiol Cell Physiol 2021; 322:C49-C62. [PMID: 34817270 DOI: 10.1152/ajpcell.00285.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Administration of branched-chain amino acids (BCAA) has been suggested to enhance mitochondrial biogenesis, including levels of PGC-1α, which may, in turn, alter kynurenine metabolism. Ten healthy subjects performed 60 min of dynamic one-leg exercise at ~70% of Wmax on two occasions. They were in random order supplied either a mixture of BCAA or flavored water (placebo) during the experiment. Blood samples were collected during exercise and recovery, and muscle biopsies were taken from both legs before, after and 90 and 180 min following exercise. Ingestion of BCAA doubled their concentration in both plasma and muscle while causing a 30-40% reduction (P<0.05 vs. placebo) in levels of aromatic amino acids in both resting and exercising muscle during 3-h recovery. The muscle concentration of kynurenine decreased by 25% (P<0.05) during recovery, similar in both resting and exercising leg and with both supplements, although plasma concentration of kynurenine during recovery was 10% lower (P<0.05) when BCAA were ingested. Ingestion of BCAA reduced the plasma concentration of kynurenic acid by 60% (P<0.01) during exercise and recovery, while the level remained unchanged with placebo. Exercise induced a 3-4-fold increase (P<0.05) in muscle content of PGC-1a1 mRNA after 90 min of recovery under both conditions, whereas levels of KAT4 mRNA and protein were unaffected by exercise or supplement. In conclusion, the reduction of plasma levels of kynurenine and kynurenic acid caused by BCAA were not associated with any changes in the level of muscle kynurenine, suggesting that kynurenine metabolism was altered in tissues other than muscle.
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Affiliation(s)
- William O Jonsson
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jonathan Ponette
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Oscar Horwath
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Tomas Rydenstam
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Karin Söderlund
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Björn Ekblom
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Michele Azzolini
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jorge L Ruas
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Eva Blomstrand
- Department of Physiology, Biomechanics and Nutrition, The Swedish School of Sport and Health Sciences and Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
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11
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Davids CJ, Næss TC, Moen M, Cumming KT, Horwath O, Psilander N, Ekblom B, Coombes JS, Peake JM, Raastad T, Roberts LA. Acute cellular and molecular responses and chronic adaptations to low-load blood flow restriction and high-load resistance exercise in trained individuals. J Appl Physiol (1985) 2021; 131:1731-1749. [PMID: 34554017 DOI: 10.1152/japplphysiol.00464.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Blood flow restriction (BFR) with low-load resistance exercise (RE) is often used as a surrogate to traditional high-load RE to stimulate muscular adaptations, such as hypertrophy and strength. However, it is not clear whether such adaptations are achieved through similar cellular and molecular processes. We compared changes in muscle function, morphology and signaling pathways between these differing training protocols. Twenty-one males and females (mean ± SD: 24.3 ± 3.1 years) experienced with resistance training (4.9 ± 2.6 years) performed nine weeks of resistance training (three times per week) with either high-loads (75-80% 1RM; HL-RT), or low-loads with BFR (30-40% 1RM; LL-BFR). Before and after the training intervention, resting muscle biopsies were collected, and quadricep cross-sectional area (CSA), muscular strength and power were measured. Approximately 5 days following the intervention, the same individuals performed an additional 'acute' exercise session under the same conditions, and serial muscle biopsies were collected to assess hypertrophic- and ribosomal-based signaling stimuli. Quadricep CSA increased with both LL-BFR (7.4±4.3%) and HL-RT (4.6±2.9%), with no significant differences between training groups (p=0.37). Muscular strength also increased in both training groups, but with superior gains in squat 1RM occurring with HL-RT (p<0.01). Acute phosphorylation of several key proteins involved in hypertrophy signaling pathways, and expression of ribosomal RNA transcription factors occurred to a similar degree with LL-BFR and HL-RT (all p>0.05 for between-group comparisons). Together, these findings validate low-load resistance training with continuous BFR as an effective alternative to traditional high-load resistance training for increasing muscle hypertrophy in trained individuals.
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Affiliation(s)
- Charlie J Davids
- School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia.,Queensland Academy of Sport, Nathan, Australia
| | - Tore C Næss
- Department of Physical Performance, Norwegian School of Sport Science, Oslo, Norway
| | - Maria Moen
- Department of Physical Performance, Norwegian School of Sport Science, Oslo, Norway
| | | | - Oscar Horwath
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Niklas Psilander
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Björn Ekblom
- Åstrand Laboratory, Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Jeff S Coombes
- School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia
| | - Jonathan M Peake
- Queensland Academy of Sport, Nathan, Australia.,Queensland University of Technology, School of Biomedical Science, Brisbane, Australia
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Science, Oslo, Norway
| | - Llion Arwyn Roberts
- School of Human Movement and Nutrition Sciences, University of Queensland, Brisbane, Australia.,Queensland Academy of Sport, Nathan, Australia.,Griffith Sports Science, School of Health Sciences and Social Work, Griffith University, Gold Coast, Australia
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12
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Valente-Silva P, Cervenka I, Ferreira DMS, Correia JC, Edman S, Horwath O, Heng B, Chow S, Jacobs KR, Guillemin GJ, Blomstrand E, Ruas JL. Effects of Tryptophan Supplementation and Exercise on the Fate of Kynurenine Metabolites in Mice and Humans. Metabolites 2021; 11:metabo11080508. [PMID: 34436450 PMCID: PMC8400416 DOI: 10.3390/metabo11080508] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 07/29/2021] [Accepted: 07/30/2021] [Indexed: 12/12/2022] Open
Abstract
The kynurenine pathway of tryptophan (TRP) degradation (KP) generates metabolites with effects on metabolism, immunity, and mental health. Endurance exercise training can change KP metabolites by changing the levels of KP enzymes in skeletal muscle. This leads to a metabolite pattern that favors energy expenditure and an anti-inflammatory immune cell profile and reduces neurotoxic metabolites. Here, we aimed to understand if TRP supplementation in untrained vs. trained subjects affects KP metabolite levels and biological effects. Our data show that chronic TRP supplementation in mice increases all KP metabolites in circulation, and that exercise reduces the neurotoxic branch of the pathway. However, in addition to increasing wheel running, we did not observe other effects of TRP supplementation on training adaptations, energy metabolism or behavior in mice. A similar increase in KP metabolites was seen in trained vs. untrained human volunteers that took a TRP drink while performing a bout of aerobic exercise. With this acute TRP administration, TRP and KYN were higher in the trained vs. the untrained group. Considering the many biological effects of the KP, which can lead to beneficial or deleterious effects to health, our data encourage future studies of the crosstalk between TRP supplementation and physical exercise.
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Affiliation(s)
- Paula Valente-Silva
- Department of Physiology and Pharmacology, Biomedicum Karolinska Institutet, 171 77 Stockholm, Sweden; (P.V.-S.); (I.C.); (D.M.S.F.); (J.C.C.)
| | - Igor Cervenka
- Department of Physiology and Pharmacology, Biomedicum Karolinska Institutet, 171 77 Stockholm, Sweden; (P.V.-S.); (I.C.); (D.M.S.F.); (J.C.C.)
| | - Duarte M. S. Ferreira
- Department of Physiology and Pharmacology, Biomedicum Karolinska Institutet, 171 77 Stockholm, Sweden; (P.V.-S.); (I.C.); (D.M.S.F.); (J.C.C.)
| | - Jorge C. Correia
- Department of Physiology and Pharmacology, Biomedicum Karolinska Institutet, 171 77 Stockholm, Sweden; (P.V.-S.); (I.C.); (D.M.S.F.); (J.C.C.)
| | - Sebastian Edman
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, 114 33 Stockholm, Sweden; (S.E.); (O.H.); (E.B.)
| | - Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, 114 33 Stockholm, Sweden; (S.E.); (O.H.); (E.B.)
| | - Benjamin Heng
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sidney, NSW 2109, Australia; (B.H.); (S.C.); (K.R.J.); (G.J.G.)
| | - Sharron Chow
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sidney, NSW 2109, Australia; (B.H.); (S.C.); (K.R.J.); (G.J.G.)
| | - Kelly R. Jacobs
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sidney, NSW 2109, Australia; (B.H.); (S.C.); (K.R.J.); (G.J.G.)
| | - Gilles J. Guillemin
- Neuroinflammation Group, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, Sidney, NSW 2109, Australia; (B.H.); (S.C.); (K.R.J.); (G.J.G.)
| | - Eva Blomstrand
- Department of Physiology, Nutrition and Biomechanics, Swedish School of Sport and Health Sciences, 114 33 Stockholm, Sweden; (S.E.); (O.H.); (E.B.)
| | - Jorge L. Ruas
- Department of Physiology and Pharmacology, Biomedicum Karolinska Institutet, 171 77 Stockholm, Sweden; (P.V.-S.); (I.C.); (D.M.S.F.); (J.C.C.)
- Correspondence:
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13
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Horwath O, Envall H, Röja J, Emanuelsson EB, Sanz G, Ekblom B, Apró W, Moberg M. Variability in vastus lateralis fiber type distribution, fiber size, and myonuclear content along and between the legs. J Appl Physiol (1985) 2021; 131:158-173. [PMID: 34013752 DOI: 10.1152/japplphysiol.00053.2021] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human skeletal muscle characteristics such as fiber type composition, fiber size, and myonuclear content are widely studied in clinical and sports-related contexts. Being aware of the methodological and biological variability of the characteristics is a critical aspect in study design and outcome interpretation, but comprehensive data on the variability of morphological features in human skeletal muscle are currently limited. Accordingly, in the present study, m. vastus lateralis biopsies (10 per subject) from young and healthy individuals, collected in a systematic manner, were analyzed for various characteristics using immunohistochemistry (n = 7) and SDS-PAGE (n = 25). None of the analyzed parameters, fiber type % (FT%), type I and II fiber cross-sectional area (fCSA), percentage fiber type area (fCSA%), myosin heavy chain composition (MyHC%), type IIX content, myonuclear content, or myonuclear domain, varied in a systematic manner longitudinally along the muscle or between the two legs. The average within-subject coefficient of variation for FT%, fCSA, fCSA%, and MyHC% ranged between 13% and 18% but was only 5% for fiber-specific myonuclear content, which reduced the variability for myonuclear domain size to 11%-12%. Pure type IIX fibers and type IIX MyHC were randomly distributed and present in <24% of the analyzed samples, with the average content being 0.1% and 1.1%, respectively. In conclusion, leg or longitudinal orientation does not seem to be an important aspect to consider when investigating human vastus lateralis characteristics. However, single muscle biopsies should preferably not be used when studying fiber type- and fiber size-related aspects, given the notable sample-to-sample variability.NEW & NOTEWORTHY This study provides a comprehensive analysis of the variability of key human skeletal muscle fiber characteristics in multiple sites along and between the m. vastus lateralis of healthy and active individuals. We found a notable but nonsystematic variability in fiber type and size, whereas myonuclear content was distinctively less variable, and the prevalence of type IIX fibers was random and very low. These data are important to consider when designing and interpreting studies including m. vastus lateralis biopsies.
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Affiliation(s)
- Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Helena Envall
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Julia Röja
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Eric B Emanuelsson
- Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
| | - Gema Sanz
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden.,Gnomics, Murcia, Spain
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Clinical Science, Intervention and Technology, Karolinska Institute, Stockholm, Sweden
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Department of Physiology and Pharmacology, Karolinska Institute, Stockholm, Sweden
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14
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Cardinale DA, Horwath O, Elings-Knutsson J, Helge T, Godhe M, Bermon S, Moberg M, Flockhart M, Larsen FJ, Hirschberg AL, Ekblom B. Enhanced Skeletal Muscle Oxidative Capacity and Capillary-to-Fiber Ratio Following Moderately Increased Testosterone Exposure in Young Healthy Women. Front Physiol 2020; 11:585490. [PMID: 33343388 PMCID: PMC7745722 DOI: 10.3389/fphys.2020.585490] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 11/10/2020] [Indexed: 11/29/2022] Open
Abstract
Background: Recently, it was shown that exogenously administered testosterone enhances endurance capacity in women. In this study, our understanding on the effects of exogenous testosterone on key determinants of oxygen transport and utilization in skeletal muscle is expanded. Methods: In a double-blinded, randomized, placebo-controlled trial, 48 healthy active women were randomized to 10 weeks of daily application of 10 mg of testosterone cream or placebo. Before and after the intervention, VO2 max, body composition, total hemoglobin (Hb) mass and blood volumes were assessed. Biopsies from the vastus lateralis muscle were obtained before and after the intervention to assess mitochondrial protein abundance, capillary density, capillary-to-fiber (C/F) ratio, and skeletal muscle oxidative capacity. Results: Maximal oxygen consumption per muscle mass, Hb mass, blood, plasma and red blood cell volumes, capillary density, and the abundance of mitochondrial protein levels (i.e., citrate synthase, complexes I, II, III, IV-subunit 2, IV-subunit 4, and V) were unchanged by the intervention. However, the C/F ratio, specific mitochondrial respiratory flux activating complex I and linked complex I and II, uncoupled respiration and electron transport system capacity, but not leak respiration or fat respiration, were significantly increased following testosterone administration compared to placebo. Conclusion: This study provides novel insights into physiological actions of increased testosterone exposure on key determinants of oxygen diffusion and utilization in skeletal muscle of women. Our findings show that higher skeletal muscle oxidative capacity coupled to higher C/F ratio could be major contributing factors that improve endurance performance following moderately increased testosterone exposure.
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Affiliation(s)
- Daniele A Cardinale
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden.,Elite Performance Centre, Bosön - Swedish Sports Confederation, Lidingö, Sweden
| | - Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Jona Elings-Knutsson
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Gynaecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Torbjörn Helge
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Manne Godhe
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | | | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Mikael Flockhart
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Filip J Larsen
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Angelica Lindén Hirschberg
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Gynaecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechanics, Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
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15
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Horwath O, Moberg M, Larsen FJ, Philp A, Apró W, Ekblom B. Influence of sex and fiber type on the satellite cell pool in human skeletal muscle. Scand J Med Sci Sports 2020; 31:303-312. [DOI: 10.1111/sms.13848] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 01/08/2023]
Affiliation(s)
- Oscar Horwath
- Department of Physiology, Nutrition and Biomechanics Åstrand Laboratory Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Marcus Moberg
- Department of Physiology, Nutrition and Biomechanics Åstrand Laboratory Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Filip J. Larsen
- Department of Physiology, Nutrition and Biomechanics Åstrand Laboratory Swedish School of Sport and Health Sciences Stockholm Sweden
| | - Andrew Philp
- Diabetes and Metabolism Division Garvan Institute of Medical Research Darlinghurst, Sydney NSW Australia
- St Vincent’s Medical School UNSW Medicine UNSW Sydney Sydney Australia
| | - William Apró
- Department of Physiology, Nutrition and Biomechanics Åstrand Laboratory Swedish School of Sport and Health Sciences Stockholm Sweden
- Department of Clinical Science, Intervention and Technology Karolinska Institutet Stockholm Sweden
| | - Björn Ekblom
- Department of Physiology, Nutrition and Biomechanics Åstrand Laboratory Swedish School of Sport and Health Sciences Stockholm Sweden
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16
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Apró W, Horwath O, Granberg J, Moberg M, Andersson E, Ekblom B. Intake Of Essential Amino Acids Stimulates Mtorc1 Signaling And Inhibits Autophagy Following Glycogen-depleted Resistance Exercise. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000670160.10958.af] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Horwath O, Apró W, Moberg M, Godhe M, Helge T, Ekblom M, Hirschberg AL, Ekblom B. Fiber type-specific hypertrophy and increased capillarization in skeletal muscle following testosterone administration in young women. J Appl Physiol (1985) 2020; 128:1240-1250. [PMID: 32191598 DOI: 10.1152/japplphysiol.00893.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
It is well established that testosterone administration induces muscle fiber hypertrophy and myonuclear addition in men; however, it remains to be determined whether similar morphological adaptations can be achieved in women. The aim of the present study was therefore to investigate whether exogenously administered testosterone alters muscle fiber morphology in skeletal muscle of young healthy, physically active women. Thirty-five young (20-35 yr), recreationally trained women were randomly assigned to either 10-wk testosterone administration (10 mg daily) or placebo. Before and after the intervention, hormone concentrations and body composition were assessed, and muscle biopsies were obtained from the vastus lateralis. Fiber type composition, fiber size, satellite cell and myonuclei content, as well as muscle capillarization were assessed in a fiber type-specific manner by immunohistochemistry. After the intervention, testosterone administration elevated serum testosterone concentration (5.1-fold increase, P = 0.001) and induced significant accretion of total lean mass (+1.9%, P = 0.002) and leg lean mass (+2.4%, P = 0.001). On the muscle fiber level, testosterone increased mixed-fiber cross-sectional area (+8.2%, P = 0.001), an effect primarily driven by increases in type II fiber size (9.2%, P = 0.006). Whereas myonuclei content remained unchanged, a numerical increase (+30.8%) was found for satellite cells associated with type II fibers in the Testosterone group. In parallel with fiber hypertrophy, testosterone significantly increased capillary contacts (+7.5%, P = 0.015) and capillary-to-fiber ratio (+9.2%, P = 0.001) in type II muscle fibers. The present study provides novel insight into fiber type-specific adaptations present already after 10 wk of only moderately elevated testosterone levels in women.NEW & NOTEWORTHY We have recently demonstrated performance-enhancing effects of moderately elevated testosterone concentrations in young women. Here we present novel evidence that testosterone alters muscle morphology in these women, resulting in type II fiber hypertrophy and improved capillarization. Our findings suggest that low doses of testosterone potently impact skeletal muscle after only 10 wk. These data provide unique insights into muscle adaptation and support the performance-enhancing role of testosterone in women on the muscle fiber level.
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Affiliation(s)
- Oscar Horwath
- Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - William Apró
- Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Marcus Moberg
- Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Manne Godhe
- Department of Sport Performance and Training, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Torbjörn Helge
- Department of Sport Performance and Training, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Maria Ekblom
- Biomechanics and Motor Control Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Angelica Lindén Hirschberg
- Division of Obstetrics and Gynaecology, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden.,Department of Gynaecology and Reproductive Medicine, Karolinska University Hospital, Stockholm, Sweden
| | - Björn Ekblom
- Åstrand Laboratory, Swedish School of Sport and Health Sciences, Stockholm, Sweden
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