Histamine, xanthine oxidase generated oxygen-derived free radicals and Helicobacter pylori in gastroduodenal inflammation and ulceration

Objective: The relationship between Helicobacter pylori (H. pylori), xanthine oxidase (XO)-induced oxygen derived free radicals (ODFR) and histamine in the induction of human gastroduodenal disorders was investigated. Patients and Methods: Histamine concentration, XO and xanthine dehydrogenase (XD) activities were measured in endoscopically obtained biopsies from 66 symptomatic patients. Results: H. pylori infection was associated with lower oxyntic and duodenal histamine in 'normal' controls (group N) (p < 0.002 and p < 0.05, respectively). Patients with gastroduodenal disease tended to have reduced mucosal concentration of histamine, but comparing H. pylori positive and negative patients, infection did not lead to a further fall in histamine concentration. H. pylori positive duodenal ulcer (DU) patients tended to have higher XO activity than group N (p = 0.051) and had a significantly lowered activity of XD, the precursor of XO (p' < 0.05). Histamine concentration at the ulcer-edge was lower while XO activity was higher than in the distant normal mucosa (p < 0.05, respectively). Gastritis (group GL) with H. pylori also had lower XD than H. pylori positive group N (p' < 0.025) but no corresponding rise in XO activity. In group N, duodenal mucosal histamine and XD activity were inversely related (R-S = -0.51, p < 0.025). Conclusions: These findings support the hypothesis that histamine, xanthine oxidase related ODFR, and H. pylori may be closely associated in the manifestations of chronic duodenal ulcer.