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Jacobs N, Mos D, Bloemers FW, van der Laarse WJ, Jaspers RT, van der Zwaard S. Low myoglobin concentration in skeletal muscle of elite cyclists is associated with low mRNA expression levels. Eur J Appl Physiol 2023:10.1007/s00421-023-05161-z. [PMID: 36877252 DOI: 10.1007/s00421-023-05161-z] [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: 11/25/2022] [Accepted: 02/14/2023] [Indexed: 03/07/2023]
Abstract
Myoglobin is essential for oxygen transport to the muscle fibers. However, measurements of myoglobin (Mb) protein concentrations within individual human muscle fibers are scarce. Recent observations have revealed surprisingly low Mb concentrations in elite cyclists, however it remains unclear whether this relates to Mb translation, transcription and/or myonuclear content. The aim was to compare Mb concentration, Mb messenger RNA (mRNA) expression levels and myonuclear content within muscle fibers of these elite cyclists with those of physically-active controls. Muscle biopsies were obtained from m. vastus lateralis in 29 cyclists and 20 physically-active subjects. Mb concentration was determined by peroxidase staining for both type I and type II fibers, Mb mRNA expression level was determined by quantitative PCR and myonuclear domain size (MDS) was obtained by immunofluorescence staining. Average Mb concentrations (mean ± SD: 0.38 ± 0.04 mM vs. 0.48 ± 0.19 mM; P = 0.014) and Mb mRNA expression levels (0.067 ± 0.019 vs. 0.088 ± 0.027; P = 0.002) were lower in cyclists compared to controls. In contrast, MDS and total RNA per mg muscle were not different between groups. Interestingly, in cyclists compared to controls, Mb concentration was only lower for type I fibers (P < 0.001), but not for type II fibers (P > 0.05). In conclusion, the lower Mb concentration in muscle fibers of elite cyclists is partly explained by lower Mb mRNA expression levels per myonucleus and not by a lower myonuclear content. It remains to be determined whether cyclists may benefit from strategies that upregulate Mb mRNA expression levels, particularly in type I fibers, to enhance their oxygen supply.
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Affiliation(s)
- Nina Jacobs
- Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Daniek Mos
- Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Frank W Bloemers
- Department for Trauma Surgery, Amsterdam UMC, Amsterdam, The Netherlands
| | | | - Richard T Jaspers
- Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Stephan van der Zwaard
- Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands.
- Laboratory for Myology, Department of Human Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
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2
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van der Laarse WJ, Bogaards SJP, Schalij I, Vonk Noordegraaf A, Vaz FM, van Groen D. Work and oxygen consumption of isolated right ventricular papillary muscle in experimental pulmonary hypertension. J Physiol 2022; 600:4465-4484. [PMID: 35993114 DOI: 10.1113/jp282991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Accepted: 08/12/2022] [Indexed: 11/08/2022] Open
Abstract
Right-sided myocardial mechanical efficiency (work output/metabolic energy input) in pulmonary hypertension can be severely reduced. We determined the contribution of intrinsic myocardial determinants of efficiency using papillary muscle preparations from monocrotaline-induced pulmonary hypertensive (MCT-PH) rats. The hypothesis tested was that efficiency is reduced by mitochondrial dysfunction in addition to increased activation heat reported previously. Right ventricular muscle preparations were subjected to 5 Hz sinusoidal length changes at 37°C. Work and suprabasal oxygen consumption (V ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ ) were measured before and after cross-bridge inhibition by blebbistatin. Cytosolic cytochrome c concentration, myocyte cross-sectional area, proton permeability of the inner mitochondrial membrane and monoamine oxidase and glucose 6-phosphate dehydrogenase activities and phosphatidylglycerol/cardiolipin contents were determined. Mechanical efficiency ranged from 23% to 11% in control (n = 6) and from 22% to 1% in MCT-PH (n = 15) and correlated with work (r2 = 0.68, P < 0.0001) but not withV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ (r2 = 0.004, P = 0.7919).V ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ for cross-bridge cycling was proportional to work (r2 = 0.56, P = 0.0005). Blebbistatin-resistantV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ (r2 = 0.32, P = 0.0167) and proton permeability of the mitochondrial inner membrane (r2 = 0.36, P = 0.0110) correlated inversely with efficiency. Together, these variables explained the variance of efficiency (coefficient of multiple determination r2 = 0.79, P = 0.0001). Cytosolic cytochrome c correlated inversely with work (r2 = 0.28, P = 0.0391), but not with efficiency (r2 = 0.20, P = 0.0867). Glucose 6-phosphate dehydrogenase, monoamine oxidase and phosphatidylglycerol/cardiolipin increased in the right ventricular wall of MCT-PH but did not correlate with efficiency. Reduced myocardial efficiency in MCT-PH is a result of activation processes and mitochondrial dysfunction. The variance of work and the ratio of activation heat reported previously and blebbistatin-resistantV ̇ O 2 ${\dot{V}}_{{{\rm{O}}}_{\rm{2}}}$ are discussed. KEY POINTS: Mechanical efficiency of right ventricular myocardium is reduced in pulmonary hypertension. Increased energy use for activation processes has been demonstrated previously, but the contribution of mitochondrial dysfunction is unknown. Work and oxygen consumption are determined during work loops. Oxygen consumption for activation and cross-bridge cycling confirm the previous heat measurements. Cytosolic cytochrome c concentration, proton permeability of the mitochondrial inner membrane and phosphatidylglycerol/cardiolipin are increased in experimental pulmonary hypertension. Reduced work and mechanical efficiency are related to mitochondrial dysfunction. Upregulation of the pentose phosphate pathway and a potential gap in the energy balance suggest mitochondrial dysfunction in right ventricular overload is a resiult of the excessive production of reactive oxygen species.
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Affiliation(s)
- Willem J van der Laarse
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Sylvia J P Bogaards
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Ingrid Schalij
- Department of Pulmonology, Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Anton Vonk Noordegraaf
- Department of Pulmonology, Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Frédéric M Vaz
- Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands and Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Clinical Chemistry, Amsterdam Gastroentrology Endocrinology Metabolism, Amsterdam, Department of Pediatrics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Emma Children's Hospital, Amsterdam University Medical Centers, Core Facility Metabolomics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Duncan van Groen
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Amsterdam, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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3
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van der Zwaard S, Brocherie F, Jaspers RT. Under the Hood: Skeletal Muscle Determinants of Endurance Performance. Front Sports Act Living 2021; 3:719434. [PMID: 34423293 PMCID: PMC8371266 DOI: 10.3389/fspor.2021.719434] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/05/2021] [Indexed: 11/21/2022] Open
Abstract
In the past decades, researchers have extensively studied (elite) athletes' physiological responses to understand how to maximize their endurance performance. In endurance sports, whole-body measurements such as the maximal oxygen consumption, lactate threshold, and efficiency/economy play a key role in performance. Although these determinants are known to interact, it has also been demonstrated that athletes rarely excel in all three. The leading question is how athletes reach exceptional values in one or all of these determinants to optimize their endurance performance, and how such performance can be explained by (combinations of) underlying physiological determinants. In this review, we advance on Joyner and Coyle's conceptual framework of endurance performance, by integrating a meta-analysis of the interrelationships, and corresponding effect sizes between endurance performance and its key physiological determinants at the macroscopic (whole-body) and the microscopic level (muscle tissue, i.e., muscle fiber oxidative capacity, oxygen supply, muscle fiber size, and fiber type). Moreover, we discuss how these physiological determinants can be improved by training and what potential physiological challenges endurance athletes may face when trying to maximize their performance. This review highlights that integrative assessment of skeletal muscle determinants points toward efficient type-I fibers with a high mitochondrial oxidative capacity and strongly encourages well-adjusted capillarization and myoglobin concentrations to accommodate the required oxygen flux during endurance performance, especially in large muscle fibers. Optimisation of endurance performance requires careful design of training interventions that fine tune modulation of exercise intensity, frequency and duration, and particularly periodisation with respect to the skeletal muscle determinants.
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Affiliation(s)
- Stephan van der Zwaard
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Leiden Institute of Advanced Computer Science, Leiden University, Leiden, Netherlands
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), French Institute of Sport (INSEP), Paris, France
| | - Richard T. Jaspers
- Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
- Laboratory for Myology, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam, Netherlands
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Meijer and Vloedman's histochemical demonstration of mitochondrial coupling obeys Lambert-Beer's law in the myocardium. Histochem Cell Biol 2018; 151:85-90. [PMID: 30159782 PMCID: PMC6328523 DOI: 10.1007/s00418-018-1716-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/24/2018] [Indexed: 01/05/2023]
Abstract
Uncoupling of mitochondrial proton pumping and adenosine triphosphate (ATP) production lowers mitochondrial efficiency. Current methods to determine mitochondrial efficiency require substantial amounts of tissue and permeabilization or isolation procedures. A simple histochemical method has been described by Meijer and Vloedman (Histochemistry 69:217–232, 1980, 10.1007/BF00489769), but this was not quantitative. We found linear correlations between (1) absorbance and sections thickness and (2) absorbance and incubation time. Because the method obeys Lambert–Beer’s law, we can estimate ATP/O2 ratios for healthy and overloaded right-sided rat myocardium. We related mitochondrial efficiency to the ratio between cardiolipin and its precursor phosphatidylglycerol. We found a non-linear relationship between mitochondrial efficiency and this ratio, indicating that lower mitochondrial efficiency as found in experimental pulmonary hypertension may be due to altered composition of the mitochondrial inner membrane. We conclude that the histochemical method of Meijer and Vloedman can be applied to quantify mitochondrial efficiency.
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5
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van der Zwaard S, Brocherie F, Kom BLG, Millet GP, Deldicque L, van der Laarse WJ, Girard O, Jaspers RT. Adaptations in muscle oxidative capacity, fiber size, and oxygen supply capacity after repeated-sprint training in hypoxia combined with chronic hypoxic exposure. J Appl Physiol (1985) 2018; 124:1403-1412. [PMID: 29420150 DOI: 10.1152/japplphysiol.00946.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
In this study, we investigate adaptations in muscle oxidative capacity, fiber size and oxygen supply capacity in team-sport athletes after six repeated-sprint sessions in normobaric hypoxia or normoxia combined with 14 days of chronic normobaric hypoxic exposure. Lowland elite field hockey players resided at simulated altitude (≥14 h/day at 2,800-3,000 m) and performed regular training plus six repeated-sprint sessions in normobaric hypoxia (3,000 m; LHTLH; n = 6) or normoxia (0 m; LHTL; n = 6) or lived at sea level with regular training only (LLTL; n = 6). Muscle biopsies were obtained from the m. vastus lateralis before (pre), immediately after (post-1), and 3 wk after the intervention (post-2). Changes over time between groups were compared, including likelihood of the effect size (ES). Succinate dehydrogenase activity in LHTLH largely increased from pre to post-1 (~35%), likely more than LHTL and LLTL (ESs = large-very large), and remained elevated in LHTLH at post-2 (~12%) vs. LHTL (ESs = moderate-large). Fiber cross-sectional area remained fairly similar in LHTLH from pre to post-1 and post-2 but was increased at post-1 and post-2 in LHTL and LLTL (ES = moderate-large). A unique observation was that LHTLH and LHTL, but not LLTL, improved their combination of fiber size and oxidative capacity. Small-to-moderate differences in oxygen supply capacity (i.e., myoglobin and capillarization) were observed between groups. In conclusion, elite team-sport athletes substantially increased their skeletal muscle oxidative capacity, while maintaining fiber size, after only 14 days of chronic hypoxic residence combined with six repeated-sprint training sessions in hypoxia. NEW & NOTEWORTHY Our novel findings show that elite team-sport athletes were able to substantially increase the skeletal muscle oxidative capacity in type I and II fibers (+37 and +32%, respectively), while maintaining fiber size after only 14 days of chronic hypoxic residence combined with six repeated-sprint sessions in hypoxia. This increase in oxidative capacity was superior to groups performing chronic hypoxic residence with repeated sprints in normoxia and residence at sea level with regular training only.
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Affiliation(s)
- S van der Zwaard
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam , The Netherlands
| | - F Brocherie
- Institute of Sports Sciences (ISSUL), University of Lausanne , Lausanne , Switzerland.,Laboratory Sport, Expertise and Performance (EA 7370), Research Department, French Institute of Sport (INSEP) , Paris , France
| | - B L G Kom
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam , The Netherlands
| | - G P Millet
- Institute of Sports Sciences (ISSUL), University of Lausanne , Lausanne , Switzerland
| | - L Deldicque
- Institute of Neuroscience, Université Catholique de Louvain , Louvain-la-Neuve , Belgium
| | - W J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center , Amsterdam , The Netherlands
| | - O Girard
- Aspetar, Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre , Doha , Qatar.,School of Psychology and Exercise Science, Murdoch University , Perth , Australia
| | - R T Jaspers
- Laboratory for Myology, Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, Amsterdam Movement Sciences, Amsterdam , The Netherlands
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6
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van der Zwaard S, van der Laarse WJ, Weide G, Bloemers FW, Hofmijster MJ, Levels K, Noordhof DA, de Koning JJ, de Ruiter CJ, Jaspers RT. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body. FASEB J 2018; 32:2110-2123. [PMID: 29217665 DOI: 10.1096/fj.201700827r] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Optimizing physical performance is a major goal in current physiology. However, basic understanding of combining high sprint and endurance performance is currently lacking. This study identifies critical determinants of combined sprint and endurance performance using multiple regression analyses of physiologic determinants at different biologic levels. Cyclists, including 6 international sprint, 8 team pursuit, and 14 road cyclists, completed a Wingate test and 15-km time trial to obtain sprint and endurance performance results, respectively. Performance was normalized to lean body mass2/3 to eliminate the influence of body size. Performance determinants were obtained from whole-body oxygen consumption, blood sampling, knee-extensor maximal force, muscle oxygenation, whole-muscle morphology, and muscle fiber histochemistry of musculus vastus lateralis. Normalized sprint performance was explained by percentage of fast-type fibers and muscle volume ( R2 = 0.65; P < 0.001) and normalized endurance performance by performance oxygen consumption ( V̇o2), mean corpuscular hemoglobin concentration, and muscle oxygenation ( R2 = 0.92; P < 0.001). Combined sprint and endurance performance was explained by gross efficiency, performance V̇o2, and likely by muscle volume and fascicle length ( P = 0.056; P = 0.059). High performance V̇o2 related to a high oxidative capacity, high capillarization × myoglobin, and small physiologic cross-sectional area ( R2 = 0.67; P < 0.001). Results suggest that fascicle length and capillarization are important targets for training to optimize sprint and endurance performance simultaneously.-Van der Zwaard, S., van der Laarse, W. J., Weide, G., Bloemers, F. W., Hofmijster, M. J., Levels, K., Noordhof, D. A., de Koning, J. J., de Ruiter, C. J., Jaspers, R. T. Critical determinants of combined sprint and endurance performance: an integrative analysis from muscle fiber to the human body.
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Affiliation(s)
- Stephan van der Zwaard
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.,Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, Vrije Universiteit, Amsterdam, The Netherlands; and VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Guido Weide
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.,Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Frank W Bloemers
- Department of Physiology, Institute for Cardiovascular Research, Vrije Universiteit, Amsterdam, The Netherlands; and
| | - Mathijs J Hofmijster
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Koen Levels
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Dionne A Noordhof
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Jos J de Koning
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Cornelis J de Ruiter
- Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
| | - Richard T Jaspers
- Department of Human Movement Sciences, Faculty of Behavioural and Movement Sciences, Amsterdam Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.,Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands
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IGF-1 Attenuates Hypoxia-Induced Atrophy but Inhibits Myoglobin Expression in C2C12 Skeletal Muscle Myotubes. Int J Mol Sci 2017; 18:ijms18091889. [PMID: 28862673 PMCID: PMC5618538 DOI: 10.3390/ijms18091889] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 08/23/2017] [Accepted: 08/29/2017] [Indexed: 12/26/2022] Open
Abstract
Chronic hypoxia is associated with muscle wasting and decreased oxidative capacity. By contrast, training under hypoxia may enhance hypertrophy and increase oxidative capacity as well as oxygen transport to the mitochondria, by increasing myoglobin (Mb) expression. The latter may be a feasible strategy to prevent atrophy under hypoxia and enhance an eventual hypertrophic response to anabolic stimulation. Mb expression may be further enhanced by lipid supplementation. We investigated individual and combined effects of hypoxia, insulin-like growth factor (IGF)-1 and lipids, in mouse skeletal muscle C2C12 myotubes. Differentiated C2C12 myotubes were cultured for 24 h under 20%, 5% and 2% oxygen with or without IGF-1 and/or lipid treatment. In culture under 20% oxygen, IGF-1 induced 51% hypertrophy. Hypertrophy was only 32% under 5% and abrogated under 2% oxygen. This was not explained by changes in expression of genes involved in contractile protein synthesis or degradation, suggesting a reduced rate of translation rather than of transcription. Myoglobin mRNA expression increased by 75% under 5% O2 but decreased by 50% upon IGF-1 treatment under 20% O2, compared to control. Inhibition of mammalian target of rapamycin (mTOR) activation using rapamycin restored Mb mRNA expression to control levels. Lipid supplementation had no effect on Mb gene expression. Thus, IGF-1-induced anabolic signaling can be a strategy to improve muscle size under mild hypoxia, but lowers Mb gene expression.
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Peters EL, Offringa C, Kos D, Van der Laarse WJ, Jaspers RT. Regulation of myoglobin in hypertrophied rat cardiomyocytes in experimental pulmonary hypertension. Pflugers Arch 2016; 468:1697-707. [PMID: 27572699 PMCID: PMC5026723 DOI: 10.1007/s00424-016-1865-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 07/21/2016] [Accepted: 08/04/2016] [Indexed: 01/29/2023]
Abstract
A major problem in chronic heart failure is the inability of hypertrophied cardiomyocytes to maintain the required power output. A Hill-type oxygen diffusion model predicts that oxygen supply is limiting in hypertrophied cardiomyocytes at maximal rates of oxygen consumption and that this limitation can be reduced by increasing the myoglobin (Mb) concentration. We explored how cardiac hypertrophy, oxidative capacity, and Mb expression in right ventricular cardiomyocytes are regulated at the transcriptional and translational levels in an early stage of experimental pulmonary hypertension, in order to identify targets to improve the oxygen supply/demand ratio. Male Wistar rats were injected with monocrotaline to induce pulmonary hypertension (PH) and right ventricular heart failure. The messenger RNA (mRNA) expression levels per nucleus of growth factors insulin-like growth factor-1Ea (IGF-1Ea) and mechano growth factor (MGF) were higher in PH than in healthy controls, consistent with a doubling in cardiomyocyte cross-sectional area (CSA). Succinate dehydrogenase (SDH) activity was unaltered, indicating that oxidative capacity per cell increased. Although the Mb protein concentration was unchanged, Mb mRNA concentration was reduced. However, total RNA per nucleus was about threefold higher in PH rats versus controls, and Mb mRNA content expressed per nucleus was similar in the two groups. The increase in oxidative capacity without an increase in oxygen supply via Mb-facilitated diffusion caused a doubling of the critical extracellular oxygen tension required to prevent hypoxia (PO2crit). We conclude that Mb mRNA expression is not increased during pressure overload-induced right ventricular hypertrophy and that the increase in myoglobin content per myocyte is likely due to increased translation. We conclude that increasing Mb mRNA expression may be beneficial in the treatment of experimental PH.
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Affiliation(s)
- E L Peters
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands
| | - C Offringa
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands
| | - D Kos
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands.,Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - W J Van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - R T Jaspers
- Laboratory for Myology, Faculty of Behavioral and Movement Sciences, Department of Human Movement Sciences, MOVE Research Institute Amsterdam, Vrije Universiteit Amsterdam, van der Boechorststraat 7, 1081, BT, Amsterdam, The Netherlands.
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9
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van der Zwaard S, de Ruiter CJ, Noordhof DA, Sterrenburg R, Bloemers FW, de Koning JJ, Jaspers RT, van der Laarse WJ. Maximal oxygen uptake is proportional to muscle fiber oxidative capacity, from chronic heart failure patients to professional cyclists. J Appl Physiol (1985) 2016; 121:636-45. [PMID: 27445298 DOI: 10.1152/japplphysiol.00355.2016] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 07/19/2016] [Indexed: 12/25/2022] Open
Abstract
V̇o2 max during whole body exercise is presumably constrained by oxygen delivery to mitochondria rather than by mitochondria's ability to consume oxygen. Humans and animals have been reported to exploit only 60-80% of their mitochondrial oxidative capacity at maximal oxygen uptake (V̇o2 max). However, ex vivo quantification of mitochondrial overcapacity is complicated by isolation or permeabilization procedures. An alternative method for estimating mitochondrial oxidative capacity is via enzyme histochemical quantification of succinate dehydrogenase (SDH) activity. We determined to what extent V̇o2 max attained during cycling exercise differs from mitochondrial oxidative capacity predicted from SDH activity of vastus lateralis muscle in chronic heart failure patients, healthy controls, and cyclists. V̇o2 max was assessed in 20 healthy subjects and 28 cyclists, and SDH activity was determined from biopsy cryosections of vastus lateralis using quantitative histochemistry. Similar data from our laboratory of 14 chronic heart failure patients and 6 controls were included. Mitochondrial oxidative capacity was predicted from SDH activity using estimated skeletal muscle mass and the relationship between ex vivo fiber V̇o2 max and SDH activity of isolated single muscle fibers and myocardial trabecula under hyperoxic conditions. Mitochondrial oxidative capacity predicted from SDH activity was related (r(2) = 0.89, P < 0.001) to V̇o2 max measured during cycling in subjects with V̇o2 max ranging from 9.8 to 79.0 ml·kg(-1)·min(-1) V̇o2 max measured during cycling was on average 90 ± 14% of mitochondrial oxidative capacity. We conclude that human V̇o2 max is related to mitochondrial oxidative capacity predicted from skeletal muscle SDH activity. Mitochondrial oxidative capacity is likely marginally limited by oxygen supply to mitochondria.
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Affiliation(s)
- Stephan van der Zwaard
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands;
| | - C Jo de Ruiter
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands
| | - Dionne A Noordhof
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands
| | - Renske Sterrenburg
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands
| | - Frank W Bloemers
- Department of Trauma Surgery, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | - Jos J de Koning
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands
| | - Richard T Jaspers
- Faculty of Behavioural and Movement Sciences, Department of Human Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; Laboratory for Myology, Faculty of Behavioural and Movement Sciences, Vrije Universiteit Amsterdam, MOVE Research Institute Amsterdam, Amsterdam, The Netherlands; and
| | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
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10
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van Beek-Harmsen BJ, van der Laarse WJ. Immunohistochemical Determination of Cytosolic Cytochrome c Concentration in Cardiomyocytes. J Histochem Cytochem 2016; 53:803-7. [PMID: 15995138 DOI: 10.1369/jhc.4c6527.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cytochrome c release from the intermembrane space of mitochondria is one of the triggers of apoptosis. There is no histochemical method available to demonstrate cytochrome c in cryostat sections, possibly because small cytosolic proteins diffuse readily into aqueous fixation media. This report shows that it is possible to demonstrate cytochrome c release in cardiomyocytes in failing myocardium using vapor fixation of cryostat sections and immunohistochemistry. The method is calibrated using sections from gelatin blocks containing known concentrations of cytochrome c. The method is applied to the hypertrophied right ventricular wall of rats in which pulmonary hypertension was induced by monocrotaline. Cytochrome c release is found in a fraction of the cardiomyocytes, leading to a mosaic-staining pattern. Cytochrome c release was found in myocytes over the full range of cross-sectional area (from 1 to 3.9 times control) in the hypertrophied myocardium. Cytosolic cytochrome c concentrations up to 0.4–0.5 mM occur frequently.
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Affiliation(s)
- Brechje J van Beek-Harmsen
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands.
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11
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Ruiter G, Manders E, Happé CM, Schalij I, Groepenhoff H, Howard LS, Wilkins MR, Bogaard HJ, Westerhof N, van der Laarse WJ, de Man FS, Vonk-Noordegraaf A. Intravenous iron therapy in patients with idiopathic pulmonary arterial hypertension and iron deficiency. Pulm Circ 2015; 5:466-72. [PMID: 26401247 DOI: 10.1086/682217] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 02/25/2015] [Indexed: 12/29/2022] Open
Abstract
UNLABELLED In patients with idiopathic pulmonary arterial hypertension (iPAH), iron deficiency is common and has been associated with reduced exercise capacity and worse survival. Previous studies have shown beneficial effects of intravenous iron administration. In this study, we investigated the use of intravenous iron therapy in iron-deficient iPAH patients in terms of safety and effects on exercise capacity, and we studied whether altered exercise capacity resulted from changes in right ventricular (RV) function and skeletal muscle oxygen handling. Fifteen patients with iPAH and iron deficiency were included. Patients underwent a 6-minute walk test, cardiopulmonary exercise tests, cardiac magnetic resonance imaging, and a quadriceps muscle biopsy and completed a quality-of-life questionnaire before and 12 weeks after receiving a high dose of intravenous iron. The primary end point, 6-minute walk distance, was not significantly changed after 12 weeks (409 ± 110 m before vs. 428 ± 94 m after; P = 0.07). Secondary end points showed that intravenous iron administration was well tolerated and increased body iron stores in all patients. In addition, exercise endurance time (P < 0.001) and aerobic capacity (P < 0.001) increased significantly after iron therapy. This coincided with improved oxygen handling in quadriceps muscle cells, although cardiac function at rest and maximal [Formula: see text] were unchanged. Furthermore, iron treatment was associated with improved quality of life (P < 0.05). In conclusion, intravenous iron therapy in iron-deficient iPAH patients improves exercise endurance capacity. This could not be explained by improved RV function; however, increased quadriceps muscle oxygen handling may play a role. ( TRIAL REGISTRATION ClinicalTrials.gov identifier NCT01288651).
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Affiliation(s)
- Gerrina Ruiter
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands ; Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Emmy Manders
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands ; Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Chris M Happé
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands ; Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Ingrid Schalij
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands ; Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Herman Groepenhoff
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Luke S Howard
- National Pulmonary Hypertension Service, Hammersmith Hospital, Imperial College Healthcare National Health Service Trust, London, United Kingdom
| | - Martin R Wilkins
- National Institute for Health Research-Wellcome Trust Imperial Clinical Research Facility, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, United Kingdom
| | - Harm J Bogaard
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands
| | - Nico Westerhof
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands
| | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Frances S de Man
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands
| | - Anton Vonk-Noordegraaf
- Department of Pulmonology, Institute for Cardiovascular Research, Vrije Universiteit (VU) University Medical Center, Amsterdam, The Netherlands
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12
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Jaspers RT, Testerink J, Della Gaspera B, Chanoine C, Bagowski CP, van der Laarse WJ. Increased oxidative metabolism and myoglobin expression in zebrafish muscle during chronic hypoxia. Biol Open 2014; 3:718-27. [PMID: 25063194 PMCID: PMC4133725 DOI: 10.1242/bio.20149167] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/17/2014] [Indexed: 11/25/2022] Open
Abstract
Fish may be extremely hypoxia resistant. We investigated how muscle fibre size and oxidative capacity in zebrafish (Danio rerio) adapt during severe chronic hypoxia. Zebrafish were kept for either 3 or 6 weeks under chronic constant hypoxia (CCH) (10% air/90%N2 saturated water). We analyzed cross-sectional area (CSA), succinate dehydrogenase (SDH) activity, capillarization, myonuclear density, myoglobin (Mb) concentration and Mb mRNA expression of high and low oxidative muscle fibres. After 3 weeks of CCH, CSA, SDH activity, Mb concentration, capillary and myonuclear density of both muscle fibre types were similar as under normoxia. In contrast, staining intensity for Mb mRNA of hypoxic high oxidative muscle fibres was 94% higher than that of normoxic controls (P<0.001). Between 3 and 6 weeks of CCH, CSA of high and low oxidative muscle fibres increased by 25 and 30%, respectively. This was similar to normoxic controls. Capillary and myonuclear density were not changed by CCH. However, in high oxidative muscle fibres of fish maintained under CCH, SDH activity, Mb concentration as well as Mb mRNA content were higher by 86%, 138% and 90%, respectively, than in muscle fibres of fish kept under normoxia (P<0.001). In low oxidative muscle fibres, SDH activity, Mb and Mb mRNA content were not significantly changed. Under normoxia, the calculated interstitial oxygen tension required to prevent anoxic cores in muscle fibres (PO2crit) of high oxidative muscle fibres was between 1.0 and 1.7 mmHg. These values were similar at 3 and 6 weeks CCH. We conclude that high oxidative skeletal muscle fibres of zebrafish continue to grow and increase oxidative capacity during CCH. Oxygen supply to mitochondria in these fibres may be facilitated by an increased Mb concentration, which is regulated by an increase in Mb mRNA content per myonucleus.
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Affiliation(s)
- Richard T Jaspers
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, 1081 BT Amsterdam, The Netherlands
| | - Janwillem Testerink
- Laboratory for Myology, MOVE Research Institute Amsterdam, Faculty of Human Movement Sciences, VU University Amsterdam, 1081 BT Amsterdam, The Netherlands Department of Integrative Zoology, Institute of Biology, Leiden University, 2333 BE Leiden, The Netherlands
| | | | | | | | - Willem J van der Laarse
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, 1007 MB Amsterdam, The Netherlands
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13
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The interventricular septum in pulmonary hypertension does not show features of right ventricular failure. Int J Cardiol 2014; 173:509-12. [DOI: 10.1016/j.ijcard.2014.03.064] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 03/09/2014] [Indexed: 11/20/2022]
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14
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Kim-Shapiro DB, Gladwin MT. Mechanisms of nitrite bioactivation. Nitric Oxide 2014; 38:58-68. [PMID: 24315961 PMCID: PMC3999231 DOI: 10.1016/j.niox.2013.11.002] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 11/19/2013] [Accepted: 11/21/2013] [Indexed: 12/18/2022]
Abstract
It is now accepted that the anion nitrite, once considered an inert oxidation product of nitric oxide (NO), contributes to hypoxic vasodilation, physiological blood pressure control, and redox signaling. As such, its application in therapeutics is being actively tested in pre-clinical models and in human phase I-II clinical trials. Major pathways for nitrite bioactivation involve its reduction to NO by members of the hemoglobin or molybdopterin family of proteins, or catalyzed dysproportionation. These conversions occur preferentially under hypoxic and acidic conditions. A number of enzymatic systems reduce nitrite to NO and their activity and importance are defined by oxygen tension, specific organ system and allosteric and redox effectors. In this work, we review different proposed mechanisms of nitrite bioactivation, focusing on analysis of kinetics and experimental evidence for the relevance of each mechanism under different conditions.
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Affiliation(s)
- Daniel B Kim-Shapiro
- Department of Physics, Wake Forest University, Winston-Salem, NC 27109, United States; Translational Science Center, Wake Forest University, Winston-Salem, NC 27109, United States.
| | - Mark T Gladwin
- Heart, Lung, Blood and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15213, United States; Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, United States.
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15
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van Eif VWW, Bogaards SJP, van der Laarse WJ. Intrinsic cardiac adrenergic (ICA) cell density and MAO-A activity in failing rat hearts. J Muscle Res Cell Motil 2013; 35:47-53. [DOI: 10.1007/s10974-013-9373-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 12/06/2013] [Indexed: 12/26/2022]
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16
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Ruiter G, Ying Wong Y, de Man FS, Louis Handoko M, Jaspers RT, Postmus PE, Westerhof N, Niessen HW, van der Laarse WJ, Vonk-Noordegraaf A. Right ventricular oxygen supply parameters are decreased in human and experimental pulmonary hypertension. J Heart Lung Transplant 2013; 32:231-40. [DOI: 10.1016/j.healun.2012.09.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/10/2012] [Accepted: 09/14/2012] [Indexed: 10/27/2022] Open
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Chotichayapong C, Wiengsamut K, Chanthai S, Sattayasai N, Tamiya T, Kanzawa N, Tsuchiya T. Isolation of heat-tolerant myoglobin from Asian swamp eel Monopterus albus. FISH PHYSIOLOGY AND BIOCHEMISTRY 2012; 38:1533-1543. [PMID: 22538454 DOI: 10.1007/s10695-012-9644-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2011] [Accepted: 04/09/2012] [Indexed: 05/31/2023]
Abstract
Myoglobin from Asian swamp eel Monopterus albus was purified from fish muscle using salt fractionation followed by column chromatography and molecular filtration. The purified Mb of 0.68 mg/g wet weight of muscle was determined for its molecular mass by MALDI-TOF-MS to be 15,525.18 Da. Using isoelectric focusing technique, the purified Mb showed two derivatives with pI of 6.40 and 7.12. Six peptide fragments of this protein identified by LC-MS/MS were homologous to Mbs of sea raven Hemitripterus americanus, yellowfin tuna Thunnus albacores, blue marlin Makaira nigicans, common carp Cyprinus carpio, and goldfish Carassius auratus. According to the Mb denaturation, the swamp eel Mb had thermal stability higher than walking catfish Clarias batrachus Mb and striped catfish Pangasius hypophthalmus Mb, between 30 and 60 (°)C. For the thermal stability of Mb, the swamp eel Mb showed a biphasic behavior due to the O(2) dissociation and the heme orientation disorder, with the lowest increase in both Kd(f) and Kd(s). The thermal sensitivity of swamp eel Mb was lower than those of the other Mbs for both of fast and slow reaction stages. These results suggest that the swamp eel Mb globin structure is thermally stable, which is consistent with heat-tolerant behavior of the swamp eel particularly in drought habitat.
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Affiliation(s)
- Chatrachatchaya Chotichayapong
- Department of Chemistry, Faculty of Science, Center of Excellence for Innovation in Chemistry, Khon Kaen University, 123 Mittrapab Road, T. Ni-Muang, A. Muang, Khon Kaen, 40002, Thailand.
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18
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Smeding L, van der Laarse WJ, van Veelen TA, Lamberts RR, Niessen HWM, Kneyber MCJ, Groeneveld ABJ, Plötz FB. Early myocardial dysfunction is not caused by mitochondrial abnormalities in a rat model of peritonitis. J Surg Res 2011; 176:178-84. [PMID: 21816428 DOI: 10.1016/j.jss.2011.05.055] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 05/09/2011] [Accepted: 05/26/2011] [Indexed: 10/18/2022]
Abstract
BACKGROUND Patients with complicated intra-abdominal infections are prone to develop multiple organ failure, including myocardial dysfunction. We hypothesized that early dysfunction during sepsis is associated with inflammation, mitochondrial injury, impaired mitochondrial function, and activation of mitochondrial biogenesis. MATERIALS AND METHODS Rats received lipopolysaccharide (LPS, n = 11) intraperitoneally. Healthy rats (n = 6) served as controls. Myocardial function was measured ex vivo in an isolated Langendorff-perfused heart set-up. Myocardial vascular cell adhesion molecule-1 (VCAM-1) expression was determined by immunofluorescence microscopy. Cytochrome c release and cytochrome c oxidase (COX IV) activity were measured by immunohistochemistry and enzyme histochemistry, respectively. Protein expression of tumor necrosis factor-α (TNF-α), B-cell lymphoma (Bcl)-2, peroxisome proliferator activated receptor γ cofactor 1α (PGC-1α), and mitochondrial transcription factor A (TFAM) were analyzed by Western blot technique. Mitochondria were studied by electron microscopy. RESULTS Two hours after LPS injection, developed pressure had decreased and after 4 h myocardial contractility (+dP/dt) and relaxation (-dP/dt) also had decreased. TNF-α protein expression was increased after 2 h and returned to normal at 4 h, whereas after 4 h VCAM-1 expression was higher in LPS-treated animals. At 2 h a substrate-dependent increase in COXIV-activity was seen, but no mitochondrial damage occurred as cytochrome c release, COX IV activity and Bcl-2, PGC-1α or TFAM expression were not changed. Electron microscopy did not reveal differences in myocardial mitochondrial characteristics between LPS-treated and control rats. CONCLUSIONS Early myocardial dysfunction in sepsis is associated with myocardial inflammation but not with mitochondrial injury, impaired mitochondrial function, or activated mitochondrial biogenesis.
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Affiliation(s)
- Lonneke Smeding
- Department of Pediatric Intensive Care, VU University Medical Center, Amsterdam, The Netherlands.
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19
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The time course of myonuclear accretion during hypertrophy in young adult and older rat plantaris muscle. Ann Anat 2010; 193:56-63. [PMID: 20833519 DOI: 10.1016/j.aanat.2010.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Revised: 06/30/2010] [Accepted: 08/10/2010] [Indexed: 02/04/2023]
Abstract
To investigate whether accretion of myonuclei precedes or follows the increase in fibre cross-sectional area and whether this time course is affected by age, left plantaris muscle of 5- and 25-month-old male Wistar rats was overloaded by denervation of its synergists for 1, 2 or 4 weeks. Contralateral plantaris muscle served as control. Myonuclei were counted in haematoxylin-stained cross-sections. While hypertrophy (33% in young adult) became significant after 2 weeks overload (p<0.01), the myonuclear number was increased only at 4 weeks of overload (p<0.001). The time course and magnitude of hypertrophy were similar in young adult and older rats. Older muscles contained 26% more myonuclei per mm fibre length (p=0.001) and had a 10-fold larger proportion of central myonuclei (p<0.001) than young adult muscles. In conclusion, our data indicate that muscle fibre hypertrophy precedes the acquisition of new myonuclei and that the ability to develop hypertrophy is not attenuated or delayed in 25-month-old rat muscle.
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20
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Redout EM, van der Toorn A, Zuidwijk MJ, van de Kolk CWA, van Echteld CJA, Musters RJP, van Hardeveld C, Paulus WJ, Simonides WS. Antioxidant treatment attenuates pulmonary arterial hypertension-induced heart failure. Am J Physiol Heart Circ Physiol 2010; 298:H1038-47. [DOI: 10.1152/ajpheart.00097.2009] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ROS have been implicated in the development of pathological ventricular hypertrophy and the ensuing contractile dysfunction. Using the rat monocrotaline (MCT) model of pulmonary arterial hypertension (PAH), we recently reported oxidative stress in the failing right ventricle (RV) with no such stress in the left ventricle of the same hearts. We used the antioxidant EUK-134 to assess the role of ROS in the pathological remodeling and dysfunction of the RV. PAH was induced by an injection of MCT (80 mg/kg, day 0), treatment with EUK-134 (25 mg/kg, once every 2 days) of control and MCT-injected animals [congestive heart failure (CHF) group] was started on day 10, and animals were analyzed on day 22. EUK-134 treatment of the CHF group attenuated cardiomyocyte hypertrophy and associated changes in mRNA expression (myosin heavy chain-β and deiodinase type 3). It also reduced RV oxidative stress and proapoptotic signaling and prevented interstitial fibrosis. Cardiac MRI showed that ROS scavenging did not affect the 37% increase in end-diastolic volume of the RV in the CHF relative to the control group, but the threefold increase in end-systolic volume was reduced by 42% in the EUK-134-treated CHF group. The improved systolic function was confirmed using echocardiography by an assessment of tricuspid annular plane systolic excursion. These data indicate an important role of ROS in RV cardiomyocyte hypertrophy and contractile dysfunction due to PAH and show the potential of EUK-class antioxidants as complementary therapeutics in the treatment of RV dysfunction in PAH.
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Affiliation(s)
- Everaldo M. Redout
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
- Department of Anesthesiology, VU University Medical Center Amsterdam, Amsterdam, The Netherlands
| | | | - Marian J. Zuidwijk
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
| | - Cees W. A. van de Kolk
- Department of Cardiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht; and
| | - Cees J. A. van Echteld
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
- Department of Cardiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht; and
| | - René J. P. Musters
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
| | - Cornelis van Hardeveld
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
| | - Walter J. Paulus
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
| | - Warner S. Simonides
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center Amsterdam, Amsterdam
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21
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Bekedam MA, van Beek-Harmsen BJ, van Mechelen W, Boonstra A, van der Laarse WJ. Myoglobin concentration in skeletal muscle fibers of chronic heart failure patients. J Appl Physiol (1985) 2009; 107:1138-43. [PMID: 19661455 DOI: 10.1152/japplphysiol.00149.2009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine the myoglobin concentration in skeletal muscle fibers of chronic heart failure (CHF) patients and to calculate the effect of myoglobin on oxygen buffering and facilitated diffusion. Myoglobin concentration, succinate dehydrogenase (SDH) activity, and cross-sectional area of individual muscle fibers from the vastus lateralis of five control and nine CHF patients were determined using calibrated histochemistry. CHF patients compared with control subjects were similar with respect to myoglobin concentration: type I fibers 0.69 +/- 0.11 mM (mean +/- SD), type II fibers 0.52 +/- 0.07 mM in CHF vs. type I fibers 0.70 +/- 0.09 mM, type II fibers 0.49 +/- 0.07 mM in control, whereas SDH activity was significantly lower in CHF in both fiber types (P < 0.01). The myoglobin concentration in type I fibers was higher than in type II fibers (P < 0.01). Consequently, the oxygen buffering capacity, calculated from myoglobin concentration/SDH activity was increased in CHF: type I fibers 11.4 +/- 2.1 s, type II fibers 13.6 +/- 3.9 s in CHF vs. type I fibers 7.8 +/- 0.9 s, type II fibers 7.5 +/- 1.0 s in control, all P < 0.01). The calculated extracellular oxygen tension required to prevent core anoxia (Po2(crit)) in muscle fibers was similar when controls were compared with patients in type I fibers 10.3 +/- 0.9 Torr in CHF and 11.5 +/- 3.3 Torr in control, but was lower in type II fibers of patients 6.1 +/- 2.8 Torr in CHF and 14.7 +/- 6.2 Torr in control, P < 0.01. The lower Po2(crit) of type II fibers may facilitate oxygen extraction from capillaries. Reduced exercise tolerance in CHF is not due to myoglobin deficiency.
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Affiliation(s)
- Martijn A Bekedam
- Department of Physiology, Van der Boechorststraat 7, 1081 BT, Amsterdam, The Netherlands
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22
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Duncker DJ, Boontje NM, Merkus D, Versteilen A, Krysiak J, Mearini G, El-Armouche A, de Beer VJ, Lamers JMJ, Carrier L, Walker LA, Linke WA, Stienen GJM, van der Velden J. Prevention of myofilament dysfunction by beta-blocker therapy in postinfarct remodeling. Circ Heart Fail 2009; 2:233-42. [PMID: 19808345 DOI: 10.1161/circheartfailure.108.806125] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Myofilament contractility of individual cardiomyocytes is depressed in remote noninfarcted myocardium and contributes to global left ventricular pump dysfunction after myocardial infarction (MI). Here, we investigated whether beta-blocker therapy could restore myofilament contractility. METHODS AND RESULTS In pigs with a MI induced by ligation of the left circumflex coronary artery, beta-blocker therapy (bisoprolol, MI+beta) was initiated on the first day after MI. Remote left ventricular subendocardial biopsies were taken 3 weeks after sham or MI surgery. Isometric force was measured in single permeabilized cardiomyocytes. Maximal force (F(max)) was lower, whereas Ca(2+) sensitivity was higher in untreated MI compared with sham (both P<0.05). The difference in Ca(2+) sensitivity was abolished by treatment of cells with the beta-adrenergic kinase, protein kinase A. beta-blocker therapy partially reversed F(max) and Ca(2+) sensitivity to sham values and significantly reduced passive force. Despite the lower myofilament Ca(2+) sensitivity in MI+beta compared with untreated myocardium, the protein kinase A induced reduction in Ca(2+) sensitivity was largest in cardiomyocytes from myocardium treated with beta-blockers. Phosphorylation of beta-adrenergic target proteins (myosin binding protein C and troponin I) did not differ among groups, whereas myosin light chain 2 phosphorylation was reduced in MI, which coincided with increased expression of protein phosphatase 1. beta-blockade fully restored the latter alterations and significantly reduced expression of protein phosphatase 2a. CONCLUSIONS beta-blockade reversed myofilament dysfunction and enhanced myofilament responsiveness to protein kinase A in remote myocardium after MI. These effects likely contribute to the beneficial effects of beta-blockade on global left ventricular function after MI.
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Affiliation(s)
- Dirk J Duncker
- Department of Biochemistry, Cardiovascular Research School COEUR, Erasmus MC, University Medical Center Rotterdam, Thoraxcenter, Rotterdam, The Netherlands
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Gussakovsky E, Jilkina O, Yang Y, Kupriyanov V. Hemoglobin plus myoglobin concentrations and near infrared light pathlength in phantom and pig hearts determined by diffuse reflectance spectroscopy. Anal Biochem 2008; 382:107-15. [DOI: 10.1016/j.ab.2008.07.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 07/21/2008] [Accepted: 07/26/2008] [Indexed: 11/27/2022]
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Sarcoplasmic reticulum ATPase activity in type I and II skeletal muscle fibres of chronic heart failure patients. Int J Cardiol 2008; 133:185-90. [PMID: 18279980 DOI: 10.1016/j.ijcard.2007.12.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2007] [Accepted: 12/11/2007] [Indexed: 11/22/2022]
Abstract
BACKGROUND Reduced exercise tolerance and muscle weakness are present in patients with CHF. Altered metabolism, histology and function in skeletal muscle of patients with CHF have been reported. The sarcoplasmic reticulum (SR) has control of Ca(++) release and uptake required for contraction and relaxation, respectively, and uses a considerable amount of energy. Little is known about SR alterations in CHF. We determined sarcoplasmic reticulum adenosine triphosphatase (SR ATPase) activity in different types of skeletal muscle fibres of CHF patients. METHODS SR ATPase activity, succinate dehydrogenase (SDH) activity and myofibrillar adenosine triphosphatase (M ATPase) activity in single fibres of the vastus lateralis muscle in 16 CHF patients and 5 controls was determined using quantitative enzyme histochemistry. RESULTS SR ATPase activity of type II skeletal muscle fibers was significantly higher compared to type I fibres. SR ATPase activity in type II skeletal muscle fibres of CHF patients was higher than in control subjects. CONCLUSION Increased skeletal muscle SR ATPase activity contributes to reduced exercise tolerance in CHF patients.
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25
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Bouwman RA, van't Hof FNG, de Ruijter W, van Beek-Harmsen BJ, Musters RJP, de Lange JJ, Boer C. The mechanism of sevoflurane-induced cardioprotection is independent of the applied ischaemic stimulus in rat trabeculae. Br J Anaesth 2006; 97:307-14. [PMID: 16849387 DOI: 10.1093/bja/ael174] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Sevoflurane protects the myocardium against ischaemic injury through protein kinase C (PKC) activation, mitochondrial K+ATP-channel (mitoK+ATP) opening and production of reactive oxygen species (ROS). However, it is unclear whether the type of ischaemia determines the involvement of these signalling molecules. We therefore investigated whether hypoxia (HYP) or metabolic inhibition (MI), which differentially inhibit the mitochondrial electron transport chain (ETC), are comparable concerning the relative contribution of PKC, mitoK+ATP and ROS in sevoflurane-induced cardioprotection. METHODS Rat right ventricular trabeculae were isolated and isometric contractile force (Fdev) was measured. Trabeculae were subjected to HYP (hypoxic glucose-free buffer; 40 min) or MI (glucose-free buffer, 2 mM cyanide; 30 min), followed by 60 min recovery (60 min). Contractile recovery (Fdev,rec) was determined at the end of the recovery period and expressed as a percentage of Fdev before hypoxia or MI, respectively. Chelerythrine (CHEL; 6 microM), 5-hydroxydecanoic acid sodium (100 microM) and n-(2-mercaptopropionyl)-glycine (MGP; 300 microM) were used to inhibit PKC, mitoK+ATP and ROS, respectively. RESULTS Fdev,rec after HYP was reduced to 47 (3)% (P<0.001 vs control; n=5) whereas MI reduced Fdev,rec to 28 (5)% (P<0.001 vs control; n=5). A 15 min period of preconditioning with sevoflurane (3.8%) equally increased contractile recovery after HYP [76 (9)%; P<0.05 vs HYP] and MI [67 (8)%; P<0.01 vs MI]. Chelerythrine, 5-hydroxydecanoate and n-(2-mercaptopropionyl)-glycine abolished the protective effect of sevoflurane in both ischaemic models. Trabeculae subjected to HYP or MI did not demonstrate any increased apoptotic or necrotic markers. CONCLUSIONS PKC, mitoK+ATP and ROS are involved in sevoflurane-induced cardioprotection after HYP or MI, suggesting that the means of mitochondrial ETC inhibition does not determine the signal transduction pathway for cardioprotection by anaesthetics.
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Affiliation(s)
- R A Bouwman
- Department of Anesthesiology, VU University Medical Center -Institute for Cardiovascular Research Vrije Universiteit De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.
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van der Laarse WJ, des Tombe AL, van Beek-Harmsen BJ, Lee-de Groot MBE, Jaspers RT. Krogh's diffusion coefficient for oxygen in isolated Xenopus skeletal muscle fibers and rat myocardial trabeculae at maximum rates of oxygen consumption. J Appl Physiol (1985) 2005; 99:2173-80. [PMID: 16051713 DOI: 10.1152/japplphysiol.00470.2005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The value of the diffusion coefficient for oxygen in muscle is uncertain. The diffusion coefficient is important because it is a determinant of the extracellular oxygen tension at which the core of muscle fibers becomes anoxic (Po(2crit)). Anoxic cores in muscle fibers impair muscular function and may limit adaptation of muscle cells to increased load and/or activity. We used Hill's diffusion equations to determine Krogh's diffusion coefficient (Dalpha) for oxygen in single skeletal muscle fibers from Xenopus laevis at 20 degrees C (n = 6) and in myocardial trabeculae from the rat at 37 degrees C (n = 9). The trabeculae were dissected from the right ventricular myocardium of control (n = 4) and monocrotaline-treated, pulmonary hypertensive rats (n = 5). The cross-sectional area of the preparations, the maximum rate of oxygen consumption (Vo(2 max)), and Po(2crit) were determined. Dalpha increased in the following order: Xenopus muscle fibers Dalpha = 1.23 nM.mm(2).mmHg(-1).s(-1) (SD 0.12), control rat trabeculae Dalpha = 2.29 nM.mm(2).mmHg(-1).s(-1) (SD 0.24) (P = 0.0012 vs. Xenopus), and hypertrophied rat trabeculae Dalpha = 6.0 nM.mm(2).mmHg(-1).s(-1) (SD 2.8) (P = 0.039 vs. control rat trabeculae). Dalpha increased with extracellular space in the preparation (Spearman's rank correlation coefficient = 0.92, P < 0.001). The values for Dalpha indicate that Xenopus muscle fibers cannot reach Vo(2 max) in vivo because Po(2crit) can be higher than arterial Po(2) and that hypertrophied rat cardiomyocytes can become hypoxic at the maximum heart rate.
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Affiliation(s)
- Willem J van der Laarse
- Dept. of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
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27
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van Weel V, Deckers MML, Grimbergen JM, van Leuven KJM, Lardenoye JHP, Schlingemann RO, van Nieuw Amerongen GP, van Bockel JH, van Hinsbergh VWM, Quax PHA. Vascular Endothelial Growth Factor Overexpression in Ischemic Skeletal Muscle Enhances Myoglobin Expression In Vivo. Circ Res 2004; 95:58-66. [PMID: 15155530 DOI: 10.1161/01.res.0000133247.69803.c3] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Therapeutic angiogenesis using vascular endothelial growth factor (VEGF) is considered a promising new therapy for patients with arterial obstructive disease. Clinical improvements observed consist of improved muscle function and regression of rest pain or angina. However, direct evidence for improved vascularization, as evaluated by angiography, is weak. In this study, we report an angiogenesis-independent effect of VEGF on ischemic skeletal muscle, ie, upregulation of myoglobin after VEGF treatment. Mice received intramuscular injection with adenoviral VEGF-A or either adenoviral LacZ or PBS as control, followed by surgical induction of acute hindlimb ischemia at day 3. At day 6, capillary density was increased in calf muscle of Ad.VEGF-treated versus control mice (
P
<0.01). However, angiographic score of collateral arteries was unchanged between Ad.VEGF-treated and control mice. More interestingly, an increase in myoglobin was observed in Ad.VEGF-treated mice. Active myoglobin was 1.5-fold increased in calf muscle of Ad.VEGF-treated mice (
P
≤0.01). In addition, the number of myoglobin-stained myofibers was 2.6-fold increased in Ad.VEGF-treated mice (
P
=0.001). Furthermore, in ischemic muscle of 15 limb amputation patients, VEGF and myoglobin were coexpressed. Finally, in cultured C2C12 myotubes treated with rhVEGF, myoglobin mRNA was 2.8-fold raised as compared with PBS-treated cells (
P
=0.02). This effect could be blocked with the VEGF receptor tyrosine kinase inhibitor SU5416. In conclusion, we show that VEGF upregulates myoglobin in ischemic muscle both in vitro and in vivo. Increased myoglobin expression in VEGF-treated muscle implies an improved muscle oxygenation, which may, at least partly, explain observed clinical improvements in VEGF-treated patients, in the absence of improved vascularization.
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Affiliation(s)
- Vincent van Weel
- Gaubius Laboratory TNO-PG, PO Box 2215 2301CE, Leiden, the Netherlands.
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Guidi A, Castigliego L, Preziuso S, Gaspari P, Gianfaldoni D, Del Bono G. Immunological and histochemical investigation of darkened turkey muscles. Vet Res Commun 2003; 27 Suppl 1:687-90. [PMID: 14535498 DOI: 10.1023/b:verc.0000014248.41842.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- A Guidi
- Department of Animal Pathology, Prophylaxis and Food Hygiene, University of Pisa, Viale delle Piagge 2, Pisa, Italy.
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29
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Des Tombe AL, Van Beek-Harmsen BJ, Lee-De Groot MBE, Van Der Laarse WJ. Calibrated histochemistry applied to oxygen supply and demand in hypertrophied rat myocardium. Microsc Res Tech 2002; 58:412-20. [PMID: 12226811 DOI: 10.1002/jemt.10153] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Oxygen supply and demand of individual cardiomyocytes during the development of myocardial hypertrophy is studied using calibrated histochemical methods. An oxygen diffusion model is used to calculate the critical extracellular oxygen tension (PO(2,crit)) required by cardiomyocytes to prevent hypoxia during hypertrophic growth, and determinants of PO(2,crit) are estimated using calibrated histochemical methods for succinate dehydrogenase activity, cardiomyocyte cross-sectional area, and myoglobin concentration. The model calculation demonstrates that it is essential to calibrate the histochemical methods, so that absolute values for the relevant parameters are obtained. The succinate dehydrogenase activity, which is proportional to the maximum rate of oxygen consumption, and the myoglobin concentration hardly change while the cardiomyocytes grow. The cross-sectional area of the cardiomyocytes, which increases up to threefold in the right ventricular wall due to pulmonary hypertension in monocrotaline-treated rats, is the most important determinant of PO(2,crit) in this model of myocardial hypertrophy. The relationship between oxygen supply and demand at the level of the cardiomyocyte can be investigated using paired determinations of spatially integrated succinate dehydrogenase activity and capillary density. Hypoxia-inducible factor 1alpha can be demonstrated by immunohistochemistry in cardiomyocytes with high PO(2,crit) and increased spatially integrated succinate dehydrogenase activity, indicating that limited oxygen supply affects gene expression in these cells. We conclude that a mismatch of oxygen supply and demand may develop during hypertrophic growth, which can play a role in the transition from myocardial hypertrophy to heart failure.
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Affiliation(s)
- A L Des Tombe
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, 1081 BT Amsterdam, The Netherlands
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30
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de Beer EL, Bottone AE, van Rijk MC, van der Velden J, Voest EE. Dexrazoxane pre-treatment protects skinned rat cardiac trabeculae against delayed doxorubicin-induced impairment of crossbridge kinetics. Br J Pharmacol 2002; 135:1707-14. [PMID: 11934811 PMCID: PMC1573287 DOI: 10.1038/sj.bjp.0704621] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. Dexrazoxane (DXR, ICRF-187) has been shown both in animal studies and clinical trials to provide a substantial cardioprotection when co-administered with anthracycline drugs like Doxorubicin (DOX). In a previous study, we showed that chronic DOX treatment in rats is associated with a clear impairment of the crossbridge kinetics and shift in myosin iso-enzymes. 2. The present study was adopted to investigate whether the cardioprotective action of DXR involves preservation of the normal actin-myosin interaction. Rats were treated for 4 weeks with either DOX at a weekly dose of 2 mg kg(-1) (i.v.), or were pre-injected with DXR (40 mg kg(-1), i.v.) at a 20 : 1 dose ratio 30 min prior to the DOX infusion. Rats receiving saline or DXR alone were included in the experiments. Cardiac trabeculae were isolated 4 weeks after the last infusion and were skinned with detergent. 3. Crossbridge turnover kinetics were studied after application of rapid length perturbations of varying amplitudes in Ca(2+)-activated preparations. DXR treatment offered a significant protection against the DOX-induced impairment of the crossbridge kinetics in isolated cardiac trabeculae. Time constants describing transitions between different crossbridge states were restored to normal in both the quick release protocol and the slack-test. DXR prevented the shift from the 'high ATPase' alpha-myosin heavy chain (MHC) isoform towards the 'low-ATPase' beta-MHC isoform in the ventricles. 4. We conclude that pre-administration of DXR in rats greatly reduces the deleterious effects of chronic DOX treatment on the trabecular actin - myosin crossbridge cycle. Preventing direct deleterious effects on the actin - myosin crossbridge system may provide a new target for preventing or reducing DOX-related cardiotoxicity and may enable patients to continue the treatment beyond currently imposed limits.
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Affiliation(s)
- Evert L de Beer
- Department of Medical Physiology and Sports Medicine, Utrecht University, University Medical Center Utrecht, P.O. Box 85060, 3508 AB Utrecht, The Netherlands.
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31
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Pääsuke M, Ereline J, Gapeyeva H. Neuromuscular fatigue during repeated exhaustive submaximal static contractions of knee extensor muscles in endurance-trained, power-trained and untrained men. ACTA PHYSIOLOGICA SCANDINAVICA 1999; 166:319-26. [PMID: 10468669 DOI: 10.1046/j.1365-201x.1999.00573.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The neural and muscular changes during fatigue produced in repeated submaximal static contractions of knee extensors were measured. Three groups of differently adapted male subjects (power-trained, endurance-trained and untrained, 15 in each) performed the exercise that consisted of 10 trials of submaximal static contractions at the level of 40% of maximal voluntary contraction (MVC) force till exhaustion with the inter-trial rest intervals of 1 min. MVC force, reaction time and patellar reflex time components before and after the fatiguing exercise and following 5, 10 and 15 min of recovery were recorded. Endurance-trained athletes had a significantly longer holding times for all the 10 trials compared with power-trained athletes and untrained subjects. However, no significant differences in static endurance between power-trained athletes and untrained subjects were noted. The fatigue test significantly prolonged the time between onset of electrical and mechanical activity (electromechanical delay) in voluntary and reflex contractions. The electromechanical delay in voluntary contraction condition for power-trained and untrained subjects and in reflex condition for endurance-trained subjects had not recovered 15 min after cessation of exercise. No significant changes in the central component of visual reaction time (premotor time of MVC) and latency of patellar reflex were noted after fatiguing static exercise. It is concluded, that in this type of exercise the fatigue development may be largely owing to muscle contractile failure.
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Affiliation(s)
- M Pääsuke
- University of Tartu, Institute of Exercise Biology, Tartu, Estonia
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de Groot B, Zuurbier CJ, van Beek JH. Dynamics of tissue oxygenation in isolated rabbit heart as measured with near-infrared spectroscopy. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 276:H1616-24. [PMID: 10330246 DOI: 10.1152/ajpheart.1999.276.5.h1616] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We investigated the role of myoglobin (Mb) in supplying O2 to mitochondria during transitions in cardiac workload. Isovolumic rabbit hearts (n = 7) were perfused retrogradely with hemoglobin-free Tyrode solution at 37 degrees C. Coronary venous O2 tension was measured polarographically, and tissue oxygenation was measured with two-wavelength near-infrared spectroscopy (NIRS), both at a time resolution of approximately 2 s. During transitions to anoxia, 68 +/- 2% (SE) of the NIRS signal was due to Mb and the rest to cytochrome oxidase. For heart rate steps from 120 to 190 or 220 beats/min, the NIRS signal decreased significantly by 6.9 +/- 1.3 or 11.1 +/- 2.1% of the full scale, respectively, with response times of 11.0 +/- 0.8 or 9.1 +/- 0.5 s, respectively. The response time of end-capillary O2 concentration ([O2]), estimated from the venous [O2], was 8.6 +/- 0.8 s for 190 beats/min (P < 0.05 vs. NIRS time) or 8.5 +/- 0.9 s for 220 beats/min (P > 0.05). The mean response times of mitochondrial O2 consumption (VO2) were 3.7 +/- 0.7 and 3.6 +/- 0.6 s, respectively. The deoxygenation of oxymyoglobin (MbO2) accounted for only 12-13% of the total decrease in tissue O2, with the rest being physically dissolved O2. During 11% reductions in perfusion flow at 220 beats/min, Mb was 1.5 +/- 0.4% deoxygenated (P < 0.05), despite the high venous PO2 of 377 +/- 17 mmHg, indicating metabolism-perfusion mismatch. We conclude that the contribution of MbO2 to the increase of VO2 during heart rate steps in saline-perfused hearts was small and slow compared with that of physically dissolved O2.
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Affiliation(s)
- B de Groot
- Laboratory for Physiology, Institute for Cardiovascular Research, Vrije Universiteit, 1081 BT Amsterdam, The Netherlands.
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