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P077. Proteolytic and oxidative degradation of the polypeptides of the mucous membrane of the colon in patients with ulcerative colitis

A. Volkov1, L. Mamedova1, A. Gorina1, G. Tarasova1, T. Kazariyan1

1Rostov State Medical University, Gastroenterology, Rostov on Don, Russian Federation

Background: One of the most important and early markers of cell's oxidative damage are carbonized forms of proteins that accumulate in body tissues in case of excessive production of active oxygen forms.

Methods: In this context, we studied the spontaneous and metal-catalyzed protein's oxidation (MCPO) in the colon's mucosa n = 47 patients with various forms of UC in the active phase of exacerbation. Determination of MCPO conducted spectrophotometrically analyzed the spontaneous and MCPO of the colon's mucous (CM). The intensity of the MCPO is calculated according to the level of carbonyl derivatives, using a molar extinction coefficient equal to 22×103 × M1, cm1. Depending on the severity and location of the pathological process patients were divided into 3 groups: group I – patients with left-sided localization and moderate severe; Groups II and III – patients with total localization of the UC. Control group – healthy volunteers (mean age 23.5+2.2).

Results: In all groups of patients with UC noted a significant increase in spontaneous (2.82+0.35 mmol/g) and MCPO (4.54+0.56 mmol/g), which exceeded the value of the control group at 3 (0.92+0.12) and 2.6 (1.71+0.24) times, respectively (p < 0.05). The maximum increase in markers of oxidative damage of components of the CM was observed in patients with total form of UC. Thus, in case of severe disease spontaneous increases and MCPO was 4.43+0.14 mmol/g and 6.11+0.31 mmol/g, which is in 4.8 and 3.6 times higher than the activity values enzymes in the control group (p < 0.05). In cases with first detected UC MCPO has been insignificantly increased in groups 1 and 2. With total defeat of the colon and severe course of UC increased MCPO to 2.63+0.2 mmol/g, which is 2.8 times higher than control (p < 0.05). If the duration of the disease 10 or more years, the MCPO raised in all groups of patients: 1.61+0.51; 3.8+0.11 and 6.24+0.08 mmol/g, respectively (p < 0.05), which is 1.7, 4.1 and 6.8 times exceed the value of control. With a short anamnesis and medium-severe course of UC increase rate was 2.3+1.6 and 2.8+0.22 mmol/g, which exceeded the value of the control group only 30% and 64% respectively (p > 0.05). The maximum gain of the MCPO of proteins was in patients with total defeat of the CM: 5.6+0.1 mmol/g and 7.5+0.1 mmol/g, which is in 3.3 and 4.4 times higher than similar parametres in healthy.

Conclusions: The flow of UC is accompanied by the intensification of MCPO, which confirms the role of oxidative stress in the pathogenesis of the UC.