Omeprazole attenuates neutrophil-endothelial cell adhesive interaction induced by extracts of Helicobacter pylori

In this study, the influence of omeprazole on the adhesive activity of neut rophils, provided by an extract of Helicobacter pylori, was determined. Hum an neutrophils were collected from peripheral blood and labelled with a flu orochrome. Helicobacter pylori (NCTC11637) was cultured and its water extra ct was obtained by centrifugation of the bacterial suspension. Neutrophils were incubated with the extract in a plastic plate. Percentage adherence wa s calculated by measuring the fluorescence of floating and adherent cells. Rat mesenteric venule was prepared on an intravital microscope and the numb er of neutrophils which adhered to venular endothelium was counted. Neutrop hil adherence to the plastic plate was increased by the presence of H. pylo ri extract. Pretreatment with omeprazole significantly decreased this adher ence in a dose-dependent manner (10(-6) - 10(-4) mol/L). Neutrophil adheren ce to the mesenteric venule was also increased by H. pylori extract and sig nificantly inhibited by omeprazole. These results indicate that the neutrop hil-endothelial adhesive interaction is inhibited by omeprazole, suggesting that omeprazole prevents neutrophil recruitment to the gastric mucosa asso ciated with H. pylori infection.