title: Altered skeletal muscle (mitochondrial) properties in patients with mitochondrial DNA single deletion myopathy.
abstract: Mitochondrial myopathy severely affects skeletal muscle structure and function resulting in defective oxidative phosphorylation. However, the major pathomechanisms and therewith effective treatment approaches remain elusive. Therefore, the aim of the present study was to investigate disease-related impairments in skeletal muscle properties in patients with mitochondrial myopathy. Accordingly, skeletal muscle biopsies were obtained from six patients with moleculargenetically diagnosed mitochondrial myopathy (one male and five females, 53 ± 9 years) and eight age- and gender-matched healthy controls (two males and six females, 58 ± 14 years) to determine mitochondrial respiratory capacity of complex I-V, mitochondrial volume density and fiber type distribution.
  
  
  
  Mitochondrial volume density (4.0 ± 0.5 vs. 5.1 ± 0.8 %) as well as respiratory capacity of complex I-V were lower (P < 0.05) in mitochondrial myopathy and associated with a higher (P < 0.001) proportion of type II fibers (65.2 ± 3.6 vs. 44.3 ± 5.9 %). Additionally, mitochondrial volume density and maximal oxidative phosphorylation capacity correlated positively (P < 0.05) to peak oxygen uptake.
  
  
  
  Mitochondrial myopathy leads to impaired mitochondrial quantity and quality and a shift towards a more glycolytic skeletal muscle phenotype.
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.|Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.|Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Saskia Maria
authors.initials: SM
authors.lastname: Gehrig
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
authors.forename: Violeta
authors.initials: V
authors.lastname: Mihaylova
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Frese
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
authors.forename: Sandro Manuel
authors.initials: SM
authors.lastname: Mueller
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
authors.forename: Maria
authors.initials: M
authors.lastname: Ligon-Auer
authors.affiliation: Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland.|Exercise Physiology Lab, Institute of Human Movement Sciences, ETH Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Spengler
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland.
authors.forename: Jens A
authors.initials: JA
authors.lastname: Petersen
authors.affiliation: Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.|Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors.forename: Carsten
authors.initials: C
authors.lastname: Lundby
authors.affiliation: Department of Neurology, University Hospital Zurich, Frauenklinikstrasse 26, 8091, Zurich, Switzerland. hans.jung@usz.ch.|Zurich Center for Integrative Human Physiology (ZIHP), Winterthurerstrasse 190, 8057, Zurich, Switzerland. hans.jung@usz.ch.
authors.forename: Hans H
authors.initials: HH
authors.lastname: Jung
mesh_terms: D000328:Adult; D001823:Body Composition / Q000235:genetics / Q000502:physiology; D004272:DNA, Mitochondrial / Q000235:genetics; D004734:Energy Metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D046529:Microscopy, Electron, Transmission; D008875:Middle Aged; D017240:Mitochondrial Myopathies / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology*; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology* / Q000503:physiopathology* / Q000648:ultrastructure; D009468:Neuromuscular Diseases / Q000235:genetics / Q000473:pathology / Q000503:physiopathology
chemical_list: D004272:DNA, Mitochondrial
keywords: Bioenergetics; Fat oxidation; Mitochondria; Mitochondrial cytopathy; Neuromuscular disease; Skeletal muscle phenotype