title: High cytochrome c oxidase expression links to severe skeletal energy failure by (31)P-MRS spectroscopy in mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the energy metabolism and mitochondrial function in skeletal muscle from patients with Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS) or chronic progressive external ophthalmoplegia (CPEO) using phosphorus magnetic resonance spectroscopy ((31)P-MRS), to determine whether abnormally increasing cytochrome c oxidase (COX), as detected in muscle biopsy, could be a cause for MELAS.
  
  
  METHODS
  (31)P-MRS was performed on the quadriceps femoris muscle of 12 healthy volunteers and 11 patients diagnosed as MELAS or CPEO by muscle biopsy and genetic analysis. All subjects experienced a state of rest, 5-min exercise, and 5-min recovery protocol in a supine position.
  
  
  RESULTS
  Compared to CPEO, MELAS patients typically exhibited COX-positive ragged-red fibers (RRFs) as well as strongly SDH-positive blood vessels (SSVs). However, based on (31)P-MRS results, MELAS showed a higher inorganic phosphate (Pi)/phosphocreatine (PCr) ratio and lower ATP/PCr ratio during exercise and delayed Pi/PCr and ATP/PCr recovery to normal.
  
  
  CONCLUSIONS
  This study suggests that high COX expression contributes to severe skeletal energy failure by (31)P-MRS spectroscopy in MELAS.
authors.affiliation: Department of Neurology, Drum Tower Hospital of Nanjing Medical University, Nanjing, China.
authors.forename: Ai-Hua
authors.initials: AH
authors.lastname: Liu
authors.forename: Feng-Nan
authors.initials: FN
authors.lastname: Niu
authors.forename: Lei-Lei
authors.initials: LL
authors.lastname: Chang
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Liu
authors.forename: Jie-Yu
authors.initials: JY
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhou
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Wu
authors.forename: Yun
authors.initials: Y
authors.lastname: Xu
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D016022:Case-Control Studies; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D017241:MELAS Syndrome / Q000235:genetics / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000473:pathology / Q000503:physiopathology; D017246:Ophthalmoplegia, Chronic Progressive External / Q000235:genetics / Q000473:pathology; D010759:Phosphorus Isotopes; D055815:Young Adult
chemical_list: D010759:Phosphorus Isotopes; D003576:Electron Transport Complex IV
keywords: 31P-MRS; Cytochrome c oxidase; Energy metabolism; Mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes; Muscle biopsy