Gastric and duodenal juxtamucosal pH and Helicobacter pylori

One of the results of gastric cytoprotection is the generation of a juxtamucosal stable pH, maintained close to neutrality by several factors among which bicarbonate secretion and mucus layer. Since Helicobacter pylori (HP) induces structural and functional changes in the gastric mucus, this study was carried out to investigate the relationship between juxtamucosal pH and HP colonization. Thirty-one dyspeptic subjects who denied a past history of gastric or duodenal ulcer and free of endoscopic lesions were studied. Juxtamucosal pH of the gastric body, antrum and duodenum and gastric luminal fluid pH were measured during upper gastrointestinal endoscopy by a flexible glass electrode passed through the biopsy channel of a gastroscope. Multiple biopsies were subsequently taken for histological investigation, HP culture and a urea quick test. Twelve subjects (39%) were infected by HP (HP+). Juxtamucosal pH (mean +/- SE) was significantly lower (p = 0.0014) in the gastric body (5.67 +/- 0.16) in HP+ than in HP-negative (HP- 6.41 +/- 0.13 subjects, but not in the antrum (6.50 +/- 0.20 in HP+ vs. 6.52 +/- 0.09 in HP-) and in the duodenum (6.80 +/- 0.14 in HP+ vs. 6.94 +/- 0.08 in HP- subjects). No difference was found in gastric luminal fluid pH (1.71 +/- 0.23 in HP+ vs. 1.80 +/- 0.22 in HP- subjects). In conclusion, this study shows that dyspeptic HP+ patients have a reduced juxtamucosal pH in the gastric body but a pH in the antrum and duodenum similar to HP-subjects.