title: Helicobacter pylori eradication attenuates oxidative stress in human gastric mucosa.
abstract: OBJECTIVE
  Helicobacter pylori infection causes gastric diseases, but the responsible mechanisms are not completely understood. They can involve DNA and tissue damage induced by reactive oxygen and nitrogen species. Our aim is to investigate the effects of bacterial eradication on oxidative stress by measuring changes of relevant markers.
  
  
  METHODS
  Antral biopsies were obtained from 34 patients with chronic atrophic gastritis and peptic ulcer disease before and after bacterial eradication. The expression of inducible nitric oxide synthase (iNOS) and levels of nitrotyrosine (NTYR) and 8-hydroxy-2'-deoxyguanosine were assessed immunohistochemically as markers of nitric oxide (NO) production and of damage to proteins and DNA, respectively.
  
  
  RESULTS
  Before treatment, the percentages of patients with staining were: 56 for iNOS in inflammatory cells, 79 and 61 for NTYR and 8-hydroxy-2'-deoxyguanosine in foveolar cells, respectively, and 82 for 8-hydroxy-2'-deoxyguanosine in lymphoid follicles. NTYR staining was associated with the intensity of inflammation (p = 0.04) and gastritis activity (p = 0.07). The prevalence of 8-hydroxy-2'-deoxyguanosine tended to be associated with that of NTYR. After successful H. pylori eradication, the prevalence of iNOS and NTYR (in mild gastritis) staining decreased (p < 0.001 and p < 0.06, respectively). 8-Hydroxy-2'-deoxyguanosine staining disappeared in 24% of cases but appeared in 18% of previously negative cases despite eradication.
  
  
  CONCLUSIONS
  Targets of oxidative stress associated with H. pylori infection are inflammatory and deep foveolar cells and lymphoid follicles. This is the first report of 8-hydroxy-2'-deoxyguanosine localization in gastric mucosa. Oxidative stress is reduced by bacterial eradication in the first stages of mild gastritis. Moderate-severe gastritis may be a step that is reversible for iNOS, but partly irreversible for NTYR and 8-hydroxy-2'-deoxyguanosine.
authors: International Agency for Research on Cancer, Lyon, France.
authors: B
authors: B
authors: Pignatelli
authors: B
authors: B
authors: Bancel
authors: M
authors: M
authors: Plummer
authors: S
authors: S
authors: Toyokuni
authors: L M
authors: LM
authors: Patricot
authors: H
authors: H
authors: Ohshima
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000032:analysis; D002908:Chronic Disease; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000032:analysis / Q000276:immunology; D005260:Female; D005753:Gastric Mucosa / Q000187:drug effects* / Q000378:metabolism; D005756:Gastritis / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D016481:Helicobacter Infections / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D016480:Helicobacter pylori; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D019001:Nitric Oxide Synthase / Q000276:immunology / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D018384:Oxidative Stress / Q000187:drug effects*; D010437:Peptic Ulcer / Q000188:drug therapy* / Q000378:metabolism / Q000382:microbiology; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000032:analysis / Q000276:immunology
chemical_list: D015415:Biomarkers; C002744:3-nitrotyrosine; D014443:Tyrosine; D000080242:8-Hydroxy-2'-Deoxyguanosine; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D003849:Deoxyguanosine