title: Skeletal muscle oxidative capacity in amyotrophic lateral sclerosis.
abstract: BACKGROUND
  Mitochondrial dysfunction in the motor neuron has been suspected in amyotrophic lateral sclerosis (ALS). If mitochondrial abnormalities are also found in skeletal muscle, assessing skeletal muscle could serve as an important biomarker of disease progression.
  
  
  METHODS
  Using 31P magnetic resonance (31P-MRS) and near infrared (NIRS) spectroscopy, we compared the absolute values and reproducibility of skeletal muscle oxidative capacity in people with ALS (n = 6) and healthy adults (young, n = 7 and age-matched, n = 4).
  
  
  RESULTS
  ALS patients had slower time constants for phosphocreatine (PCr) and muscle oxygen consumption (mVO2 ) compared with young, but not age-matched controls. The coefficient of variation for the time constant was 10% (SD = 2.8%) and 17% (SD = 6.2%) for PCr and mVO2 , respectively.
  
  
  CONCLUSIONS
  People with ALS had, on average, a small but not statistically significant, impairment in skeletal muscle mitochondrial function measured by both 31P-MRS and NIRS. Both methods demonstrated good reproducibility.
authors.affiliation: Department of Kinesiology, University of Georgia, Athens, Georgia, USA.
authors.forename: Terence E
authors.initials: TE
authors.lastname: Ryan
authors.forename: Melissa L
authors.initials: ML
authors.lastname: Erickson
authors.forename: Ajay
authors.initials: A
authors.lastname: Verma
authors.forename: Juan
authors.initials: J
authors.lastname: Chavez
authors.forename: Michael H
authors.initials: MH
authors.lastname: Rivner
authors.forename: Kevin K
authors.initials: KK
authors.lastname: Mccully
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000503:physiopathology; D015331:Cohort Studies; D004185:Disability Evaluation; D005260:Female; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007866:Leg / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000503:physiopathology*; D009211:Myoglobin / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010101:Oxygen Consumption / Q000502:physiology; D010725:Phosphocreatine / Q000378:metabolism; D010758:Phosphorus; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D009211:Myoglobin; D010725:Phosphocreatine; D010758:Phosphorus; C100003:deoxyhemoglobin
keywords: MRS; NIRS; mitochondrial bioenergetics; mitochondrial function; motor neuron disease