Inducible nitric oxide synthase as a potential blood-based biomarker in inflammatory bowel diseases

AIM: Here, we evaluated the role of (iNOS) as a blood-based biomarker of inflammatory bowel diseases (IBD). BACKGROUND: Up-regulation of inducible nitric oxide synthase (iNOS) in the intestinal epithelial cells has been closely associated with the initiation and maintenance of intestinal inflammation in IBD. METHODS: In a case-control design, 59 IBD patients and 30 healthy control subjects were participated in this study. A total of 10 ml blood sample was taken from each participant. Blood leukocytes were isolated and iNOS mRNA expression level was evaluated in the isolated leukocytes using relative quantitative Real-time PCR. RESULTS: The patients’ population included 40 ulcerative colitis (UC) and 19 Crohn's disease (CD) patients. The flare and remission phase of disease were seen in 43 and 16 patients, respectively. The mean iNOS mRNA expression was not significantly different between the IBD patients and healthy controls (p=0.056). The mean iNOS mRNA expression was significantly higher in the flare phase of the disease compared to the remission phase (p=0.039). No significant difference was observed between the mean iNOS mRNA expression in the blood leukocytes of UC and CD patients (p=0.82). CONCLUSION: iNOS is differently expressed in the blood leukocytes of active vs. inactive IBD disease. Thus, it could be potentially used as a non-invasive blood-based biomarker of IBD.