title: Urinary NOx:creatinine ratios during gluten challenge in children with celiac disease.
abstract: OBJECTIVE
  Celiac disease is a gluten-induced small bowel enteropathy. Inflammation is known to be associated with enhanced nitric oxide (NO) production. An increase in urinary nitrate and nitrite (NOx) reflects increased NO production. The urinary NOx:creatinine ratio can be used as an indicator of the endogenous NO production. The aim of the study was to determine whether the urinary NOx:creatinine ratio of celiac disease patients increases during gluten challenge.
  
  
  METHODS
  The authors studied 20 patients with unconfirmed celiac disease who had been following a gluten-free diet for at least 1 year. These patients underwent an 80-day gluten challenge. Urinary samples were obtained before and 10, 20, 40, and 80 days after starting the gluten challenge. The Griess reagent method was used for measuring urinary NOx.
  
  
  RESULTS
  Gluten challenge confirmed the diagnosis of celiac disease in 15 of 20 patients. The NOx:creatinine ratios (mmol:mmol) of the biopsy-confirmed celiac disease patients were significantly higher than those of the unconfirmed celiac disease patients (0.67 vs. 0.17 on day 10; 0.78 vs. 0.15 on day 20; 0.85 vs. 0.25 on day 40; and 0.85 vs. 0.17 on day 80).
  
  
  CONCLUSIONS
  Gluten challenge resulted in an increased urinary NOx:creatinine ratio in patients with biopsy-confirmed celiac disease. The NOx:creatinine ratio could be useful for the serial evaluation of disease activity.
authors.affiliation: Department of Pediatrics, University Hospital, Maastricht, The Netherlands.
authors.forename: L
authors.initials: L
authors.lastname: Koster-Kamphuis
authors.forename: E A
authors.initials: EA
authors.lastname: van Straaten
authors.forename: W A
authors.initials: WA
authors.lastname: Kors
authors.forename: J E A R
authors.initials: JE
authors.lastname: De Schrijver
authors.forename: I M Y
authors.initials: IM
authors.lastname: Bovee-Oudenhoven
authors.forename: R
authors.initials: R
authors.lastname: vandDer Meer
authors.forename: P-Ph
authors.initials: PP
authors.lastname: Forget
mesh_terms: D002446:Celiac Disease / Q000175:diagnosis / Q000378:metabolism / Q000652:urine*; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000652:urine*; D005260:Female; D005983:Glutens / Q000378:metabolism*; D006801:Humans; D008297:Male; D009566:Nitrates / Q000652:urine; D009569:Nitric Oxide / Q000652:urine*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D009573:Nitrites / Q000652:urine
chemical_list: D009566:Nitrates; D009573:Nitrites; D009569:Nitric Oxide; D005983:Glutens; D003404:Creatinine; D019001:Nitric Oxide Synthase