Involvement of endothelin-1 in up-regulation of gastric mucosal inflammatory responses to Helicobacter pylori lipopolysaccharide

In this study, we investigated gastric mucosal inflammatory responses during Helicobacter pylori lipopolysaccharide-induced gastritis by analyzing the interplay between mucosal expression of endothelin-l (ET-1), interleukin-4 (IL-4) and tumor necrosis factor-alpha (TNF-alpha). The assays conducted 4 days after intragastric dose of H. pylori lipopolysaccharide demonstrated a pattern of acute mucosal reaction characterized by the inflammatory infiltration of the lamina propria, hyperemia, and epithelial hemorrhage. This was accompanied by a 3.1-fold increase in the mucosal expression of ET-1 and a 9-fold enhancement in TNF-alpha while the level of IL-4 showed a 20.8% decline. The results implicate ET-1 in gastric mucosal responses to H. pylori, and suggest that an increase in its level, combined with a loss of compensatory action by IL-4, may be responsible for the induction of TNF-alpha and triggering apoptotic events that exacerbate the inflammatory process. (C) 1999 Academic Press.