Increased urinary nitric oxide oxidation products in children with active coeliac disease

Background: Nitric oxide (NO) production catalyzed by iNOS (inducible NO sy nthase) is thought to take place mainly in macrophages after activation by inflammatory mediators. NO is subsequently oxidized to nitrite and nitrate, which are excreted in urine. The concentration of inflammatory mediators i n small bowel biopsy specimens from patients with coeliac disease is increa sed. The latter could induce increased NO production by stimulation of inte stinal macrophage iNOS, resulting in high levels of urinary NO oxidation pr oducts, nitrite and nitrate (NOx). Aim: In the present study we evaluated t he urinary NOx/creatinine ratios in children with active coeliac disease (n = 22), coeliac disease patients on a gluten-free diet (n = 9), healthy (n = 11) and sick control children (n = 18). Methods: The Griess reagent metho d was used for measuring urinary NOx. Results: Median NOx/creatinine ratios of active coeliac disease patients, coeliac disease patients on a gluten-f ree diet, healthy and sick control patients were 1.21, 0.19, 0.10 and 0.13 mmol/mmol, respectively. All active coeliac disease patients showed increas ed NOx/creatinine ratios. Urinary NOx/creatinine ratios of the active coeli ac disease patients were significantly higher than those of healthy control s (p < 0.0001), sick controls (p < 0.0001) and coeliac disease patients on a gluten-free diet (p < 0.0001). Conclusion: The urinary NOx/creatinine rat io is increased in patients with active coeliac disease and reverts to norm al on a gluten-free diet.