HELICOBACTER-PYLORI POTENTIATES HISTAMINE-RELEASE FROM SEROSAL RAT MAST-CELLS INVITRO

Helicobacter pylori seems to be involved in the etiology of peptic ulc er and chronic gastritis. Histamine is fundamental in gastric secretio n modulation, and some features of H. pylori-associated gastritis (ede ma, vasodilatation, inflammatory cell infiltration) are typical of the histamine-mediated response. This in vitro study has been undertaken as a preliminary step, in order to find a possible link between H. pyl ori and histamine release. H. pylori isolated from gastric biopsies ha s been tested as whole washed bacterium, whole formalin-killed bacteri um, and crude cell wall preparation with serosal mast cells obtained b y density gradient centrifugation or elutriation from peritoneal and p leural washings of male Wistar albino rats. Histamine release was assa yed fluorimetrically. No significant histamine release was obtained by testing the various bacterial preparations alone with mast cells. On the contrary, whole washed cells, whole formalin-killed cells and crud e cell walls from H. pylori have been found to potentiate compound 48/ 80 or calcium ionophore A23187-induced histamine release. Crude cell w alls showed the highest activity, whereas filtered supernatants from b roth cultures constantly appeared inactive. The enhancement in histami ne release differed between the different strains. The present in vitr o study, which shows the potentiating effect of H. pylori on histamine release, may prove interesting; however, at present, clinical implica tions cannot be inferred and further studies as well as in vivo demons trations are needed.