P389 The value of oxidative stress parameters to predict histological severity in ulcerative colitis
B. Canbakan*1, K. Atay1, E. Koroglu1, M. Tuncer1, H. Senturk2
1Istanbul University Cerrahpasa Medical School, Gastroenterology, Istanbul, Turkey, 2Bezmialem University School of Medicine, Gastroenterology, Istanbul, Turkey
Neutrophil accumulation in the mucosa and the subsequent induction of oxidative stress are major contributors for the disease progression in ulcerative colitis (UC). Therefore, we conducted this study to examine the redox parameters in tissue specimens and their influence on histopathological changes in UC.
In total, 40 UC patients (M/F 21/19, mean age 42.11 ± 11.4) were compared with 31 controls (M/F16/15, mean age 41.11 ± 12.2). Mucosal biopsies were obtained in the active period. Oxidative stress 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-squared test, Student’s t-test, Mann–Whitney test, multivariate regression analysis, and the area under receiver operating characteristic (ROC) curve were used. P-values < 0.05 were considered significant.
Moderate HI had significantly higher MPO and GPX levels (p = 0.003, 0.035, respectively) compared with the controls. Patients with severe HI had significantly higher MDA and MPO levels compared with the controls (p = 0.03 and 0.004, respectively). In patients with high HI, MDA levels correlated inversely with the GPX and SOD levels (r = - 0.69, p = 0.02, and r = -0.59, p = 0.04, respectively). Mean MDA levels were considerably higher in the presence than in the absence of acute inflammatory findings crypt abscesses (p = 0.01), mucin depletion (p = 0.03), and breaches in the surface epithelium (p = 0.04). The presence of a chronic inflammatory cell infiltrate or crypt architectural irregularities had no clear effect on MDA levels. MDA (B = 0.24, p = 0.008), and MPO levels (B = 1.59, p = 0.02), were independently associated with high HI. Increased MDA (OR 1.51; %95 CI 1.03–2.22, p = 0.034) was risk factor for high HI and increase of SOD- and GPX activity had preventive effect against high HI (OR 0.007; %95 CI 0.001–0.82, p = 0.04, and OR 0.005; %95 CI 0.02–0.62, p = 0.035, respectively). The ROC curve revealed statistically significant discriminative power of MDA and MPO levels for high HI (AUROC = 0.62 and 0.59, respectively).
We found that increased ROS and decreased antioxidant levels in patients with high histological index, increase of ROS had statistically significant discriminative power for a high degree of mucosal inflammation; enhanced oxidative stress and the subsequent depletion of antioxidant capacity was a risk factor for histopathological disease severity. Therefore, in UC therapeutic interventions should be aimed to improve the antioxidant status.