Reactive oxygen species activity and lipid peroxidation in Helicobacter pylori associated gastritis: relation to gastric mucosal ascorbic acid concentrations and effect of H pylori eradication.

BACKGROUND Helicobacter pylori is an independent risk factor for gastric cancer, and this association may be due to the bacterium causing reactive oxygen species mediated damage to DNA in the gastric epithelium. High dietary ascorbic acid intake may protect against gastric cancer by scavenging reactive oxygen species. AIMS To assess reactive oxygen species activity and damage in gastric mucosa in relation to gastric pathology and mucosal ascorbic acid level, and to determine the effect of H pylori eradication on these parameters. PATIENTS Gastric biopsy specimens were obtained for analysis from 161 patients undergoing endoscopy for dyspepsia. METHODS Reactive oxygen species activity and damage was assessed by luminol enhanced chemiluminescence and malondialdehyde equivalent estimation respectively. Ascorbic acid concentrations were measured using HPLC. RESULTS Chemiluminescence and malondialdehyde levels in gastric mucosa were higher in patients with H pylori gastritis than in those with normal histology. Successful eradication of the bacterium led to decreases in both parameters four weeks after treatment was completed. Gastric mucosal ascorbic acid and total vitamin C concentrations were not related to mucosal histology, but correlated weakly with reactive oxygen species activity (chemiluminescence and malodialdehyde levels). CONCLUSIONS Data suggest that reactive oxygen species play a pathological role in H pylori gastritis, but mucosal ascorbic acid is not depleted in this condition.