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Hypoxia refines plasticity of mitochondrial respiration to repeated muscle work

Desplanches, Dominique ; Amami, Myriam ; Dupré-Aucouturier, Sylvie ; Valdivieso, Paola ; Schmutz, Silvia ; Mueller, Matthias ; Hoppeler, Hans ; Kreis, Roland ; Flück, Martin

In: European Journal of Applied Physiology, 2014, vol. 114, no. 2, p. 405-417

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    Titre
    • Hypoxia refines plasticity of mitochondrial respiration to repeated muscle work
    Auteur
    • Desplanches, Dominique. Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534, Université Lyon 1, Villeurbanne, France
    • Amami, Myriam. Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK
    • Dupré-Aucouturier, Sylvie. Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534, Université Lyon 1, Villeurbanne, France
    • Valdivieso, Paola. Laboratory for Muscle Plasticity, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Forchstrasse 340, 8008, Zurich, Switzerland
    • Schmutz, Silvia. Institute of Anatomy, University of Bern, Bern, Switzerland
    • Mueller, Matthias. Institute of Anatomy, University of Bern, Bern, Switzerland
    • Hoppeler, Hans. Institute of Anatomy, University of Bern, Bern, Switzerland
    • Kreis, Roland. Department of Clinical Research, University of Bern, Bern, Switzerland
    • Flück, Martin. Institute for Biomedical Research into Human Movement and Health, Manchester Metropolitan University, Manchester, UK
    Type de document
    • Postprint
    Langue
    • Inglese
    Publié dans
    • European Journal of Applied Physiology, 2014, vol. 114, no. 2, p. 405-417. Springer Berlin Heidelberg
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:326552
    Summary
    Purpose: We explored whether altered expression of factors tuning mitochondrial metabolism contributes to muscular adaptations with endurance training in the condition of lowered ambient oxygen concentration (hypoxia) and whether these adaptations relate to oxygen transfer as reflected by subsarcolemmal mitochondria and oxygen metabolism in muscle. Methods: Male volunteers completed 30 bicycle exercise sessions in normoxia or normobaric hypoxia (4,000m above sea level) at 65% of the respective peak aerobic power output. Myoglobin content, basal oxygen consumption, and re-oxygenation rates upon reperfusion after 8min of arterial occlusion were measured in vastus muscles by magnetic resonance spectroscopy. Biopsies from vastus lateralis muscle, collected pre and post a single exercise bout, and training, were assessed for levels of transcripts and proteins being associated with mitochondrial metabolism. Results: Hypoxia specifically lowered the training-induced expression of markers of respiratory complex II and IV (i.e. SDHA and isoform 1 of COX-4; COX4I1) and preserved fibre cross-sectional area. Concomitantly, trends (p<0.10) were found for a hypoxia-specific reduction in the basal oxygen consumption rate, and improvements in oxygen repletion, and aerobic performance in hypoxia. Repeated exercise in hypoxia promoted the biogenesis of subsarcolemmal mitochondria and this was co-related to expression of isoform 2 of COX-4 with higher oxygen affinity after single exercise, de-oxygenation time and myoglobin content (r≥0.75). Conversely, expression in COX4I1 with training correlated negatively with changes of subsarcolemmal mitochondria (r<−0.82). Conclusion: Hypoxia-modulated adjustments of aerobic performance with repeated muscle work are reflected by expressional adaptations within the respiratory chain and modified muscle oxygen metabolism.