No additive effect between Helicobacter pylori infection and portal hypertensive gastropathy on inducible nitric oxide synthase expression in gastric mucosa of cirrhotic patients

Increased expression of inducible nitric oxide synthase (iNOS) has been reported in gastric mucosa of patients with Helicobacter pylori infection or portal hypertensive gastropathy (PHG) but whether there is an additive or synergistic impact between H. pylori and PHG on iNOS expression was unknown. Sixty cirrhotic patients and 21 age-matched control subjects without liver disease were included. Biopsies from the gastric antrum and body were obtained for quantitative histological assessment and immunohistochemical staining for iNOS. iNOS staining was detected in endothelial cells and macrophages. In the absence of PHG, H. pylori significantly induced iNOS expression in cirrhotic patients. PHG also significantly induced iNOS expression in H. pylori-negative patients. However, there was no synergistic or additive effect between H. pylori and PHG on this expression. Furthermore, expression of iNOS was significantly higher in patients with severe PHG than in those with mild PHG and without PHG.