title: Novel intravenous (13)C-methionine breath test as a measure of liver function in children with short bowel syndrome.
abstract: Monitoring hepatic function in children with short bowel syndrome (SBS) and parenteral nutrition-associated liver disease (PNALD) is currently limited to conventional blood testing or liver biopsy. Metabolism of the stable isotope L[1-(13)C]methionine occurs exclusively in liver mitochondria and can be noninvasively quantified in expired breath samples. We hypothesized that the (13)C-methionine breath test ((13)C-MBT) could be a safe, noninvasive, and valid measure of hepatic mitochondrial function in children with SBS and PNALD.
  
  
  METHODS
  Baseline breath samples were collected in 8 children with SBS before intravenous administration of 2 mg/kg of L[1-(13)C]methionine. Six paired breath samples were obtained at 20-minute intervals. The (13)CO(2) enrichment was analyzed using isotope ratio mass spectrometry.
  
  
  RESULTS
  All 8 patients (5 males; mean age, 8.9 months) tolerated the (13)C-MBT without adverse events. Two patients underwent serial testing. One patient, tested before and after resolution of cholestasis, demonstrated increased cumulative percentage dose (4.7% to 6.6%) and area under the curve (AUC) (270-303). A second patient with progressive PNALD demonstrated decreased cumulative percentage dose (from 7.8% to 5.9%) and AUC (from 335 to 288).
  
  
  CONCLUSIONS
  The (13)C-MBT is a feasible, safe, and potentially clinically relevant measure of hepatic mitochondrial function in children with SBS and PNALD.
authors.affiliation: Harvard Medical School, Children's Hospital Boston, MA 02115, USA. debora.duro@childrens.harvard.edu
authors.forename: Debora
authors.initials: D
authors.lastname: Duro
authors.forename: Christopher
authors.initials: C
authors.lastname: Duggan
authors.forename: Clarissa
authors.initials: C
authors.lastname: Valim
authors.forename: Lori
authors.initials: L
authors.lastname: Bechard
authors.forename: Shimae
authors.initials: S
authors.lastname: Fitzgibbons
authors.forename: Tom
authors.initials: T
authors.lastname: Jaksic
authors.forename: Yong-Ming
authors.initials: YM
authors.lastname: Yu
mesh_terms: D019540:Area Under Curve; D001944:Breath Tests / Q000379:methods*; D002779:Cholestasis / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D005260:Female; D006801:Humans; D007223:Infant; D008111:Liver Function Tests; D008297:Male; D008715:Methionine / Q000378:metabolism*; D010288:Parenteral Nutrition / Q000009:adverse effects; D012778:Short Bowel Syndrome / Q000378:metabolism* / Q000628:therapy
chemical_list: D008715:Methionine