Background: Helicobacter pylori (H.pylori) is associated with chronic gastritis, peptic ulcers, gastricadenocarcinomas and mucosa associated tissue lymphomas. Cytotoxin associated gene A (CagA) is one of thevirulence factors of H.pylori. It is hypothesized that reactive oxygen species (ROS) play roles in H.pylori associateddisease especially in development of gastric adenocarcinoma. Individuals infected with H.pylori bearing CagAproduce more ROS than others. 8-hydroxydeoxyguanosine (8OHdG) is an in vitro marker of DNA damage andoxidative stress. The aim of this study was to investigate the relationship between 8OHdG level, H.pylori infectionand CagA and alterations of serum 8OHdG level after H.pylori eradication. Materials and
Methods: Patientsadmitted with dyspeptic complaints and upper gastrointestinal endoscopy were assessed. H.pylori was determinedfrom histopathology of specimens. Serum 8OHdG levels of three groups (H.pylori negative, H. pylori positiveCagA negative and H.pylori positive CagA positive) were compared. Patients with H.pylori infection receivederadication therapy. Serum 8OHdG levels pretreatment and posttreatment were also compared.
Results: Intotal, 129 patients (M/F, 57/72) were enrolled in the study. Serum 8OHdG level of H.pylori negative, H. pyloripositive CagA negative and H.pylori positive CagA positive groups were significantly different (5.77±1.35 ng/ml,5.43±1.14 ng/ml and 7.57±1.25 ng/ml respectively, p=0.05). Furthermore, eradication therapy reduced serum8OHdG level (6.10±1.54 ng/ml vs 5.55±1.23 ng/ml, p=0.05).
Conclusions: Individuals infected with H.pyloribearing CagA strains have the highest serum 8OHdG level and eradication therapy decreases the serum 8OHdGlevel. To the best of our knowledge this is the first study that evaluated the effect of CagA virulence factor onserum 8OHdG level and the effect of eradication therapy on serum 8OHdG levels together. Eradication of CagAbearing H.pylori may prevent gastric adenocarcinoma by decreasing ROS. 8OHdG level may thus be a goodmarker for prevention from gastric adenocarcinoma