GASTRIC-MUCOSAL SUPEROXIDE DISMUTASES IN HELICOBACTER-PYLORI INFECTION

Background-The mucosal pathology of Helicobacter pylori infection may in part be due to excessive production of reactive oxygen metabolites (ROMs) by phagocytes. The influence of H pylori infection on mucosal s uperoxide dismutases, some major scavenger enzymes of ROM was investig ated. In humans superoxidase dismutase is present in at least two form s that is, mitochondrial manganese (Mn)-superoxide dismutase and cytop lasmic copper-zinc (CuZn)-superoxide dismutase. Methods-The amount and activity of both superoxide dismutases were measured, respectively by enzyme linked immunosorbent assay (ELISA) and spectrophotometrical en zyme activity assay, in gastric biopsy homogenates of patients with no rmal mucosa (n=39) and in patients with H pylori related gastritis (n= 71). Infection and gastritis were confirmed by a combination of cultur e, serology, and histology. Results-The amount (p<0.001) and activity (p less than or equal to 0.05) of Mn-superoxide dismutase were increas ed by about twofold to threefold, whereas the amount and activity of C uZn-superoxide dismutase showed a slight decrease in gastric mucosa of patients with H pylori gastritis, in both antrum and corpus, compared with normal mucosa of patients without H pylori infection. Mn-superox ide dismutase concentrations in biopsy specimens of histologically nor mal corpus from patients with an inflamed antrum were significantly hi gher (p<0.01) than that of patients with a histologically normal antru m. Conclusion-H pylori infection has a differential effect on mitochon drial and cytoplasmic superoxide dismutase in the gastric mucosa, refl ected by a pronounced increase in the cytokine inducible Mn-superoxide dismutase and a marginal decrease in the constitutive CuZn-superoxide dismutase.