Correlations among gastric juice pH and ammonia, Helicobacter pylori infection and gastric mucosal histology.

BACKGROUND: To assess the relationships among gastric pH and ammonia level, H. pylori infection, and gastric mucosal histology, we determined the gastric juice pH and ammonia concentration in H. pylori gastritis.
METHODS: The pH levels and ammonia concentrations were determined in gastric juice collected from 143 patients with dyspepsia during an endoscopy and compared according to a H. pylori infection. We also looked for correlations between two chemical parameters, between each of these parameters and H. pylori density, and histology.
RESULTS: Gastric pH levels and ammonia concentrations were higher in 94 infected patients than in the uninfected (3.16 vs. 1.55, p = 0.0001; 5.58 +/- 2.69 vs. 2.00 +/- 1.49 mol/L, p = 0.0001). Among 28 patients who received eradication therapy, 19 (67.9%) were successful, and their gastric pH levels and ammonia concentrations were significantly lower than those in the eradication failure group (1.60 vs. 2.33, p = 0.007; 1.77 +/- 1.28 vs. 4.02 +/- 1.20 micromoL/L, p = 0.0001). Gastric pH was significantly associated with intragastric ammonia concentration (p = 0.025) and gastritis activity (p = 0.018). Gastric pH and the ammonia level were significantly correlated with each other (rs = 0.495, p < 0.01), and with H. pylori density (rs = 0.467; rs = 0.735, p < 0.01), gastritis severity (rs = 0.343; rs = 0.478, p < 0.01), and gastritis activity (rs=0.418; rs = 0.579, p < 0.01).
CONCLUSION: Gastric juice pH and ammonia concentration reflect well the status of a H. pylori infection, and significantly correlate with each other and with H. pylori density, gastritis severity and activity. These findings suggest that intragastric ammonia produced by H. pylori may have a partial role in an increased gastric juice pH, and has a pathogenic role in H. pylori gastritis.