ABSTRACT
Background: Zonulin is a protein, reversibly increasing the permeability of the intestinal wall by changing the structure of tight junctions of the lateral surfaces of intestinal epithelial cells. Fecal zonulin is used for noninvasive assessment of increased intestinal permeability. Normal values of zonulin in stool (<= 110 ng/ml) indicate the absence of damage of the intestinal villous mucosal surface and normal density of intercellular contacts. The aim of the study was to determine the level of fecal zonulin (FZ) in the feces of ulcerative colitis (UC) patients with exacerbation of the disease and the presence of COVID-19 in the acute period and without COVID-19 to assess the degree of intestinal permeability. Method(s): 46 patients with IBD without COVID-19 (Me age - 36 years) and 31 patients with UC with the presence of COVID-19 infection in the acute period (Me age - 42 years) were examined. Untreated stool samples of patients were frozen and stored at a temperature of 80 degreeC. FZ was measured by ELISA (IDK Zonulin ELISA Kit, Immunodiagnostik AG, Germany) in ng/ml. Reference values: < 83.15 ng/ml - a variant of the norm, 83.15-110 ng/ml - an elevated level, 110 ng/ml - a high level Results: In the stool samples of patients with UC exacerbation without COVID-19 FZ was detected from 172.6 to 460.8 ng/ml (Me - 316), the average value was 322.4+/-14.6 ng/ml. In the stool samples of patients with UC exacerbation and COVID-19 infection, FZ was detected from 354.8 to 628.3 ng/ml (Me - 489.9), the average value was 472.9+/-18.4 ng/ml (p=0.000001). Conclusion(s): FZ concentration in the feces of UC patients is significantly higher in UC patients with the presence of COVID-19 infection in the acute period, which indicates a higher permeability of the intestinal wall.