Nitric oxide production in rectal dialysate is a marker of disease activity and location in children with inflammatory bowel disease

The incidence of inflammatory bowel disease (IBD) is progressively increasing in children in Western countries (1). At present, IBD diagnosis and staging is based on a combination of clinical, endoscopic, histological, and radiographic criteria, and there is no simple, noninvasive reliable individual marker for evaluating disease activity and topographical involvement, to predict relapses, and to select distinct treatment strategies (2, 3). Increased nitric oxide (NO) levels have been detected in the stools and plasma of children with IBD (4). This is the likely result of an upregulation of inducible NO synthase activity, which has been detected in intestinal mucosal segments of patients with active ulcerative colitis (UC) and, with lower intensity, of those with Crohn's disease (CD), suggesting a role of NO in IBD pathophysiology . The aim of this study was to determine whether rectal NO production, measured by a simple and noninvasive technique, reflects local inflammatory changes and disease activity in children with IBD. Forty children were included in the study: diagnosis, disease activity, and topographical involvement were obtained in all subjects by endoscopy and mucosal biopsy. Mean NO concentration was significantly higher in children with active UC than in control subjects. In nonactive UC patients and in active CD patients with rectal involvement, an overproduction of NO was also detected, but its magnitude was significantly lower than that observed in active UC children. On the contrary, in active CD children with rectal sparing NO production was similar to that of controls