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To investigate the role of cyclooxygenase (COX)-2/prostaglandin E2 (PGE2) in the process of Helicobacter pylori-induced gastric carcinogenesis, a prospective study based on an intervention trial was conducted in Linqu County, China. A total of 1401 subjects with histopathologic diagnosis were investigated at baseline, among those, 919 completed subsequent interventions (anti-H.pylori and/or celecoxib treatment). Expressions of COX-2 and Ki-67 were assessed by immunohistochemistry, and PGE2 levels were measured by enzyme immunoassay before and after interventions, respectively. We found a grade–response relationship between COX-2 expression level and risk of advanced gastric lesions at baseline. Stratified analysis indicated an additive interaction between COX-2 expression and H.pylori infection on the elevated risk of advanced gastric lesions. The odds ratios (ORs) for both factors combined were 9.31 [95% confidence interval (CI): 4.13–20.95] for chronic atrophic gastritis, 16.26 (95% CI: 7.29–36.24) for intestinal metaplasia and 21.13 (95% CI: 7.87–56.75) for dysplasia, respectively. After interventions, COX-2 expression and Ki-67 labeling index (LI) were decreased in anti-H.pylori group (OR: 1.65, 95% CI: 1.36–1.99 for COX-2; OR: 1.78, 95% CI: 1.49–2.12 for Ki-67) or anti-H.pylori followed by celecoxib group (OR: 1.41, 95% CI: 1.17–1.70 for COX-2; OR: 1.63, 95% CI: 1.37–1.94 for Ki-67). PGE2 levels were decreased in all treatment groups. Furthermore, the regression of gastric lesions was associated with the decrease of COX-2 expression or Ki-67 LI after interventions. Our findings indicate that H.pylori-induced COX-2/PGE2 pathways play an important role on the progression of precancerous gastric lesions in a Chinese population. [ABSTRACT FROM AUTHOR]

Among 2258 Helicobacter pylori-seropositive subjects randomly assigned to receive one-time H. pylori treatment with amoxicillin-omeprazole or its placebo, we evaluated the 15-year effect of treatment on gastric cancer incidence and mortality in subgroups defined by age, baseline gastric histopathology, and post-treatment infection status. We used conditional logistic and Cox regressions for covariable adjustments in incidence and mortality analyses, respectively. Treatment was associated with a statistically significant decrease in gastric cancer incidence (odds ratio = 0.36; 95% confidence interval [Cl] = 0.17 to 0.79) and mortality (hazard ratio = 0.26; 95% Cl = 0.09 to 0.79) at ages 55 years and older and a statistically significant decrease in incidence among those with intestinal metaplasia or dysplasia at baseline (odds ratio = 0.56; 95% Cl = 0.34 to 0.91). Treatment benefits for incidence and mortality among those with and without post-treatment infection were similar. Thus H. pylori treatment can benefit older members and those with advanced baseline histopathology, and benefits are present even with post-treatment infection, suggesting treatment can benefit an entire population, not just the young or those with mild histopathology. [ABSTRACT FROM AUTHOR]

Background: Randomized trials have yielded mixed results on the effects of treatment for Helicobacter pylori and little information on the effects of vitamins or garlic supplements on precancerous gastric lesions. We conducted a randomized trial to test the effects of one-time H. pylori treatment and long-term vitamin or garlic supplements in reducing the prevalence of advanced precancerous gastric lesions. Methods: Most of the adults aged 35-64 years in 13 randomly selected villages in Linqu County, Shandong Province, China, were identified and given baseline endoscopies in 1994. In 1995, 3365 eligible subjects were randomly assigned in a factorial design to three interventions or placebos: amoxicillin and omeprazole for 2 weeks in 1995 (H. pylori treatment); vitamin C, vitamin E, and selenium for 7.3 years (vitamin supplement); and aged garlic extract and steam-distilled garlic oil for 7.3 years (garlic supplement). Subjects underwent endoscopies with biopsies in 1999 and 2003, and the prevalence of precancerous gastric lesions was determined by histopathologic examination of seven standard biopsy sites. The 3365 eligible randomized subjects represented 93.5% of those with baseline endoscopy and included all baseline histologic categories except gastric cancer. Only 0.18% had normal gastric mucosa. Logistic regression was used to estimate the intervention effects on the odds of advanced precancerous gastric lesions, and t-tests were used to assess effects on histologic severity. All statistical tests were two-sided. Results: H. pylori treatment resulted in statistically significant decreases in the combined prevalence of severe chronic atrophic gastritis, intestinal metaplasia, dysplasia, or gastric cancer in 1999 (odds ratio [OR] = 0.77; 95% confidence interval [CI] = 0.62 to 0.95) and in 2003 (OR = 0.60; 95% CI = 0.47 to 0.75), and had favorable effects on the average histopathologic severity and on progression and regression of precancerous gastric lesions in 2003. H. pylori treatment did not reduce the combined prevalence of dysplasia or gastric cancer. However, fewer subjects receiving H. pylori treatment (19/1130; 1.7%) than receiving placebo (27/1128; 2.4%) developed gastric cancer (adjusted P= .14). No statistically significant favorable effects were seen for garlic or vitamin supplements. Conclusion: H. pylori treatment reduces the prevalence of precancerous gastric lesions and may reduce gastric cancer incidence, but further data are needed to prove the latter point. Long-term vitamin or garlic supplementation had no beneficial effects on the prevalence of precancerous gastric lesions or on gastric cancer incidence. [ABSTRACT FROM AUTHOR]

Base excision repair pathway may play an important role in repairing DNA damage related to Helicobacter pylori-induced inflammatory process. To evaluate the association between genetic polymorphisms of X-ray repair cross-complementing group 1 (XRCC1, Arg194Trp and Arg399Gln), adenosine diphosphate ribosyl transferase (ADPRT, Val762Ala), 8-oxoguanine DNA glycosylase (OGG1, Ser326Cys) and apurinic/apyrimidinic endonuclease 1 (APE1, Asp148Glu) and evolution of H.pylori-associated precancerous gastric lesions, a population-based cohort study was conducted in Linqu County, a high-risk area of gastric cancer in China. Genotypes were determined by polymerase chain reaction (PCR)-based denaturing high-performance liquid chromatography and PCR–restriction fragment length polymorphism analysis in 1281 H.pylori-infected subjects. We found that subjects carrying the combined XRCC1-194Arg/Trp+Trp/Trp genotype had an elevated chance of regression of gastric lesions [adjusted odds ratio (OR) = 1.44; 95% confidence interval (CI) = 1.06–1.96], whereas subjects carrying the XRCC1-399Arg/Gln+Gln/Gln genotype had a decreased chance of regression (OR = 0.68; 95% CI = 0.49–0.92). Stratified analysis indicated that an increased risk of progression was observed in subjects carrying the XRCC1-399Arg/Gln+Gln/Gln genotype (OR = 1.60; 95% CI = 1.09–2.36) or OGG1-326Ser/Cys+Cys/Cys genotype (OR = 1.95; 95% CI = 1.03–3.71) with intestinal metaplasia or dysplasia at baseline or carrying the XRCC1-399Arg/Gln+Gln/Gln genotype and smoking (OR = 1.58; 95% CI = 1.02–2.45). Furthermore, a significantly increased risk of progression was observed in subjects carrying one or two hazard genotypes of XRCC1-399 or OGG1-326, the OR was 2.83 (95% CI = 1.32–6.08), 2.22 (95% CI = 1.24–3.98) or 2.27 (95% CI = 1.26–4.10), respectively. These findings suggest that genetic polymorphisms in XRCC1-Arg194Trp, XRCC1-Arg399Gln and OGG1-Ser326Cys may play important roles in the evolution of H.pylori-associated gastric lesions in this high-risk population. [ABSTRACT FROM AUTHOR]