Reactive oxygen species activity and lipid peroxidation inHelicobacter 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.

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Antioxidant vitamin supplements do not reduce reactive oxygen species activity inHelicobacter pylorigastritis in the short term

British Journal Of Nutrition ◽

10.1079/bjn2001477 ◽

2002 ◽

Vol 87 (1) ◽

pp. 3-11 ◽

Cited By ~ 24

Author(s):

Simon M. Everett ◽

Ian M. Drake ◽

Kay L. M. White ◽

Nic P. Mapstone ◽

Douglas M. Chalmers ◽

...

Keyword(s):

Reactive Oxygen Species ◽

Ascorbic Acid ◽

Vitamin C ◽

Reactive Oxygen ◽

Antioxidant Vitamin ◽

Oxygen Species ◽

Vitamin Supplements ◽

Plasma Ascorbic Acid ◽

Species Activity ◽

H Pylori

Reactive oxygen species have been implicated inHelicobacter pylori-mediated gastric carcinogenesis, whereas diets high in antioxidant vitamins C and E are protective. We have examined the effect of vitamin C and E supplements in combination withH. pylorieradication on reactive oxygen species activity inH. pylorigastritis.H. pylori-positive patients were randomized into four groups: triple therapy alone (Bismuth chelate, tetracycline, and metronidazole for 2 weeks), vitamins alone (200 mg vitamin C and 50 mg vitamin E, both twice per day for 4 weeks), both treatments or neither. Plasma and mucosal ascorbic acid, malondialdehyde and reactive oxygen species were determined before and after treatment. Compared with normal controls (n61),H. pylori-positive patients (n117) had higher mucosal reactive oxygen species and malondialdehyde levels and lower plasma ascorbic acid. Plasma ascorbic acid doubled in both groups of patients receiving vitamins and mucosal levels also increased. Malondialdehyde and reactive oxygen species fell in patients in whomH. pyloriwas eradicated but vitamin supplements were not effective either alone or in combination withH. pylorieradication. Supplements of vitamins C and E do not significantly reduce mucosal reactive oxygen species damage inH. pylorigastritis.

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