title: 13C-breath tests for clinical investigation of liver mitochondrial function.
abstract: BACKGROUND
  Mitochondria play a major role in cell energetic metabolism; therefore, mitochondrial dysfunction inevitably participates in or even determines the onset and progression of chronic liver diseases. The assessment of mitochondrial function in vivo, by providing more insight into the pathogenesis of liver diseases, would be a helpful tool to study specific hepatic functions and to develop rational diagnostic, prognostic and therapeutic strategies.
  
  
  METHODS
  This review focuses on the utility of breath tests to assess mitochondrial function in humans and experimental animals.
  
  
  RESULTS
  The introduction in the clinical setting of specific breath tests may allow elegantly and noninvasively overcoming the difficulties caused by previous complex techniques and might provide clinically relevant information, i.e the effects of drugs on mitochondria. Substrates meeting this requirement are alpha-keto-isocaproic acid and methionine that are both decarboxylated by mitochondria. Long-and medium-chain fatty acids that are metabolized through the Krebs cycle, and benzoic acid which undergoes glycine conjugation, may also reflect the function of mitochondria.
  
  
  CONCLUSIONS
  Breath tests to assess in vivo mitochondrial function in humans represent a potentially useful diagnostic and prognostic tool in clinical investigation.
authors.affiliation: Clinica Medica "A. Murri", Department of Internal Medicine, University of Bari Medical School, Bari, Italy.
authors.forename: Ignazio
authors.initials: I
authors.lastname: Grattagliano
authors.forename: Bernhard H
authors.initials: BH
authors.lastname: Lauterburg
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Palasciano
authors.forename: Piero
authors.initials: P
authors.lastname: Portincasa
mesh_terms: D000818:Animals; D001944:Breath Tests / Q000379:methods*; D002210:Caprylates / Q000378:metabolism; D002247:Carbon Isotopes / Q000378:metabolism*; D006801:Humans; D007651:Keto Acids / Q000378:metabolism; D008111:Liver Function Tests; D008715:Methionine / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism*
chemical_list: D002210:Caprylates; D002247:Carbon Isotopes; D007651:Keto Acids; C013082:alpha-ketoisocaproic acid; D008715:Methionine; C031492:octanoic acid