Oxidative stress expression status associated to Helicobacter pylori virulence in gastric diseases

Objectives: To analyze the status of expression of inflammation markers, antioxidant and oxidant enzymes in biopsies from patients diagnosed with gastritis, gastric ulcer (GU) and gastric cancer (GC) and the Helicobacter pylori virulence from these isolated biopsies in order to evaluate a possible association among these factors. Methods: H. pylori genotype from isolated biopsies was performed by PCR. The pattern of expression of inflammation (TNF-α, IL-1β, IL-8, IL-10 and IL-12), oxidant (iNOS and Nox1) and antioxidant markers (MnSOD, GPX and CAT) of biopsies from gastritis, GU, GC and control groups was performed by RT-PCR. Results: Different from other gastric diseases studied here, gastritis is characterized by an oxidative stress with significant expression of TNF-α, IL-8, IL-12, iNOS and Nox and significant absence of MnSOD and GPX expression. Gastritis was the only condition where there was an association between TNF-α or IL-8 expression and H. pylori cagA+/vacAs1 genotype. In this case, TNF-α expression was about 3 times higher when compared to control subjects. Conclusion: In this study, only gastritis was found to be associated with significant oxidative stress marker expression of TNF-α and IL-8 that was also related to H. pylori virulence, suggesting that they are the main oxidant stress markers responsible to trigger an increase in ROS level that contributes to decrease the expression of the MnSOD and GPX.