Effect of Helicobacter pylori infection on the link between GLP-1 expression and motility of the gastrointestinal tract

BACKGROUND Although Helicobacter pylori (H. pylori) infection is closely associated with the development of peptic ulcer, its involvement in pathophysiology in the lower intestinal tract and gastrointestinal (GI) motility remains unclear. Glucagon-like peptide-1 (GLP-1) is a gut hormone produced in the lower intestinal tract and involved in GI motility. Here, we investigated the effect of H. pylori infection on the link between GLP-1 expression and motility of the GI tract. METHODS C57BL/6 mice were inoculated with a H. pylori strain. Twelve weeks later, the H. pylori-infected mice underwent H. pylori eradication treatment. GI tissues were obtained from the mice at various time intervals, and evaluated for the severity of gastric inflammatory cell infiltration and immunohistochemical expression of GLP-1 and PAX6 in the colonic mucosa. Gastrointestinal transit time (GITT) was measured by administration of carmine-red solution. RESULTS GLP-1 was expressed in the endocrine cells of the colonic mucosa, and PAX6 immunoreactivity was co-localized in such cells. The numbers of GLP-1- and PAX6-positive cells in the colon were significantly increased at 12 weeks after H. pylori infection and showed a positive correlation with each other. The GITT was significantly longer in H. pylori-infected mice than in non-infected controls and showed a positive correlation with GLP-1 expression. When H. pylori-infected mice underwent H. pylori eradication, GITT and PAX6/GLP-1 expression did not differ significantly from those in untreated H. pylori-infected mice. CONCLUSIONS H. pylori infection may impair GI motility by enhancing the colonic GLP-1/PAX6 expression.