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* = Presenting author

P165 Assessment of oxidative stress parameters for the disease activity evaluation in patients with ulcerative colitis

B. Canbakan*1, E. Koroglu1, K. Atay1, M. Tuncer1, H. Senturk2

1Istanbul University Cerrahpasa Medical School, Gastroenterology, Istanbul, Turkey, 2Bezmialem University School of Medicine, Gastroenterology, Istanbul, Turkey

Background

Neutrophils dependent oxidative stress (OS) in the intestinal mucosa plays an important role in ulcerative colitis (UC). Several antioxidants inhibit the inflammatory responses in intestinal tracts. Therefore, we investigated reactive oxygen species (ROS) and antioxidants levels in tissue specimens and their correlation with disease activity.

Methods

In total, 44 UC patients (M/F 23/21, mean age 41.2 ± 11.8) were compared with 33 controls (M/F 18/15, mean age 48.23 ± 15.12). Clinical disease activity was estimated according to Truelove–Witts Index values < 150, 150–220, and > 220 corresponded to mild, moderate, and severe, respectively. OS was estimated based on malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPX), and myeloperoxidase (MPO) levels in tissue specimens using the thiobarbituric acid-trichloroaceticacid assay for MDA-phenyltetrazolium chloride assay for SOD, method of Paglia and Valentine for GPX, and tetramethyl benzidin assay for MPO measurement. For statistical analysis Chi-square test, Student’s t-test, Mann–Whitney test, multivariate regression analysis, and the area under receiver operating characteristic (ROC) curve were used.

Results

In controls, MDA levels correlated positively with GPX, MPO, and SOD levels (r = 0.68, p = 0.02; r = 0.72, p = 0.02; r = 0.42, p = 0.03, respectively). MDA level of patients with mild AI correlated positively with GPX and SOD levels (r = 0.73, p = 0.01 and r = 0.82, p = 0.01, respectively). Patients with mild and moderate AI had similar MDA levels as the controls. Patients with severe AI had significantly higher MDA and MPO levels than the controls did (p = 0.03 and 0.004, respectively), but in patients with high AI, MDA levels correlated inversely with the GPX and SOD levels (r = - 0.79, p = 0.01 and r = -0.68, p = 0.03, respectively).The ROC curves revealed statistically significant discriminative power of MDA and MPO levels for high AI (AUROC = 0.69 and 0.58, respectively).Tissue MDA (B = 0.22, p = 0.006), and MPO levels (B = 1.48, p = 0.03), were independently associated with high AI. Increased MDA (OR 1.48; %95 CI, 1.08–2.16, p = 0.04) was risk factor for disease severity and increase of SOD- and GPX activity had preventive effect against high AI (OR 0.008; %95 CI, 0.001–0.98, p = 0.04 and OR 0.006; %95 CI, 0.02–0.67, p = 0.045, respectively).

Conclusion

Patients with severe clinical AI had increased ROS and decreased antioxidant levels. Increase of ROS was a risk factor for clinical disease activity. Our findings show that UC patients with enhanced oxidative stress and subsequent depletion of antioxidant capacity have increased risk for severe clinical activity. Therefore, therapeutic interventions with antioxidant agents should be considered for the treatment in UC patients with high clinical activity index.