Effects of Proton Pump Inhibitor on the Distribution of Helicobacter pylori and Associated Gastritis in Patients with Gastric Atrophy

Background/Aims: Acid suppression therapy is thought to be associated with the topography of Helicobacter pylori and associated gastritis, leading to corpus-predominant gastritis. This study was aimed to investigate the influence of proton pump inhibitor (PPI) treatment on the distribution of H. pylori and associated gastritis in patients with atrophic change. Methods: Patients who underwent endoscopic resection for gastric neoplasms and received PPI for 2 months were prospectively analyzed. Biopsy specimens were obtained from 5 areas in the stomach before, during, and after the treatment with PPI. Histological examination was ­performed using the updated Sydney system, and ­bacterial density of H. pylori was further graded by immunohistochemistry (ClinicalTrials.gov registration number NCT02449941). Results: A total of 15 patients were analyzed, of whom 7 had H. pylori infection. The degree of activity and inflammation were greater in patients with H. pylori infection than in those without H. pylori infection. During the PPI treatment, the density of H. pylori decreased not only in the antrum but also in the corpus. The degree of activity and inflammation improved significantly in the antrum, particularly in the presence of H. pylori infection, while the corpus gastritis was not affected by PPI use. Atrophy and intestinal metaplasia remained unchanged in both regions of the stomach. The observed changes reverted following the discontinuation of PPI treatment. Conclusion: PPI treatment decreased H. pylori both in the antrum and the corpus in patients with atrophic gastritis. Antral gastritis improved during PPI treatment, whereas no changes were found in the corpus.