H. pylori decreases gastric mucin synthesis via inhibition of galactosyltransferase

Background/Aims: Alterations of gastric mucin have been postulated as important pathogenic properties of Helicobacter pylori. In this study, we investigated gastric mucin synthesis in H. pylori-infected gastric mucosa by measuring UDP-galactosyltransferase activity, a key enzyme for the synthesis of mucin, and the amount of intracellular mucin in the gastric mucosa. Methodology: Gastric biopsy specimens were obtained from thirty-seven patients (20 H. pylori-positive and 17 H. pylori-negative). UDP-galactosyl-transferase activity of the biopsy specimens was measured by an assay system we had developed, using a peanut agglutinin lectin. The amount of intracellular mucin in the gastric epithelial cells was analyzed by measuring the cells' periodic acid-Schiff-alcian blue staining-positive substances. Results: UDP-galactosyltransferase activities in the antral mucosa, but not in the body mucosa, of H. pylori-positive patients were significantly lower than those of H. pylori-negative patients (p<0.05). The amount of intracellular mucin in antral epithelial cells of H. pylori-positive patients was significantly lower than that of H. pylori-negative patients (p<0.01). Conclusions: These findings suggest that H. pylori infection decreases gastric mucin synthesis via inhibition of UDP-galactosyltransferase. This effect may impair the gastric mucosal barrier and contribute to the mucosal injury induced by H. pylori infection.