title: Methodological characterization of the 2-keto [1-13C]isocaproate breath test to measure in vivo human mitochondrial function: application in alcoholic liver disease assessment.
abstract: BACKGROUND
  The 2-keto[1-13C]isocaproate oxidation measurement has been shown as a helpful tool in the in vivo assessment of liver mitochondrial function.
  
  
  METHODS
  The aim of this work was to study the variability of the 2-keto[1-13C]isocaproate breath test in 24 healthy controls (8 men and 16 women) and to evaluate its clinical usefulness in 20 patients (14 men and 6 women) with liver disease (7 men with history of alcoholism). Breath test was performed by measuring 13CO2 enrichment in breath before and after the oral administration of the tracer and by using isotope ratio mass spectrometry.
  
  
  RESULTS
  The intrasubject and intersubject variability of the percentage of tracer oxidized were 8 and 14%, respectively. The 2-keto[1-13C]isocaproate oxidation in women was faster (p = 0.004) and tended to be higher (p = 0.050) than in men. The percentage of oxidized tracer was lower in those patients with alcoholic liver disease than in healthy volunteers (p = 0.001) and in nonalcoholic patients (p = 0.003).
  
  
  CONCLUSIONS
  The percentage of tracer oxidized appears as a convenient parameter to detect impairment in liver mitochondrial oxidation related to alcoholism by the 2-keto[1-13C]isocaproate breath test, establishing different cutoff values depending on gender.
authors.affiliation: Department of Physiology and Nutrition, University of Navarra, Pamplona, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Parra
authors.forename: Alvaro
authors.initials: A
authors.lastname: González
authors.forename: Luis
authors.initials: L
authors.lastname: García-Villarreal
authors.forename: J Alfredo
authors.initials: JA
authors.lastname: Martínez
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001944:Breath Tests / Q000379:methods*; D002245:Carbon Dioxide / Q000378:metabolism; D002250:Carbon Radioisotopes / Q000378:metabolism; D005260:Female; D006801:Humans; D007651:Keto Acids / Q000378:metabolism*; D008108:Liver Diseases, Alcoholic / Q000378:metabolism*; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism / Q000502:physiology*; D018709:Statistics, Nonparametric
chemical_list: D002250:Carbon Radioisotopes; D007651:Keto Acids; D002245:Carbon Dioxide; C013082:alpha-ketoisocaproic acid