Nitric oxide-an endogenous inhibitor of gastric acid secretion in isolated human gastric glands

BACKGROUND: Endothelial nitric oxide synthase (eNOS) has previously been detected in the glandular part of the human gastric mucosa. Furthermore, nitric oxide (NO) has been shown to influence gastric secretion in various animal models. The present study was conducted to investigate the influence of exogenously and endogenously derived NO on histamine- and cAMP-stimulated gastric acid secretion in isolated human oxyntic glands. METHODS: Oxyntic glands were isolated from human gastric biopsies and were subsequently pre-treated with NO donors and nitric oxide synthase inhibitors and then exposed to histamine or dibutyryl-cAMP (db-cAMP). The secretory response of the glands was determined as accumulation of [(14)C]aminopyrine. RESULTS: The histamine- or db-cAMP-induced acid secretion was attenuated by L-arginine, a known source of endogenous NO, and also by the NO-donors sodium nitroprusside (SNP) and S-nitroso-N-acetyl-penicillamine (SNAP). Pre-treatment with either of the NOS inhibitors N(G)-nitro-L-arginine methyl ester (L-NAME) or N(G)-nitro-L-arginine (L-NNA) enhanced the secretory response. CONCLUSION: Our results show that NO inhibits gastric acid secretion in isolated human gastric glands, and that there is endogenous formation of NO within the glandular epithelium in the vicinity of the parietal cells

Gastroduodenal Changes Two Years After Eradication of Helicobacter pylori in a Population-Based Cohort

BACKGROUND: The main cause of chronic gastritis is Helicobacter pylori (H. pylori) infection. Some individuals with H. pylori-related chronic gastritis develop atrophy of the gastric mucosa, a risk factor for gastric neoplasia. When H. pylori-associated gastritis is encountered, it is important to be aware of its natural history and reversibility of associated histopathological and hormonal changes. METHODS: A sample of 501 volunteers from the general population in the municipality of Linkoping, Sweden, was examined with esophago-gastro-duodenoscopy (EGD) with biopsy. Blood samples were collected in the fasting state and the subjects answered a questionnaire concerning lifestyle factors, medications and disease history. At a primary follow-up examination, after 8 years, 314 participants were re-examined and those infected with H. pylori received eradication. Two years after successful eradication therapy, 82 participants attended re-examination with EGD and blood sampling, as in the previous examinations. RESULTS: In this prospective cohort study of a sample of volunteers from the general population, all of the 82 participants had chronic gastritis with at least one positive H. pylori test before eradication therapy. During follow-up, non-steroid-inflammatory-drug (NSAID) use had decreased significantly (P = 0.007, McNemar). The H. pylori serology was still positive in 79/82 subjects (P = 0.007, McNemar). The basal gastrin and cholecystokinin (CCK) concentrations both had decreased (P < 0.001 for both, Wilcoxon), whereas the P-somatostatin had increased (P < 0.001, Wilcoxon). Symptoms included in the self-administered symptom questionnaire concerned the last 3 months showed no big difference at all. The inflammation had decreased in both antrum (before 2/38/42/0 and after 60/22/0/0, P < 0.0001) and corpus (before 3/54/22/3 and after 58/23/1/0, P < 0.0001). Changes in the inflammatory activity had decreased significantly in both the antrum (P < 0.001) and the corpus (P < 0.001). Intestinal metaplasia was without changes. Regarding the duodenal bulb, the inflammation decreased. CONCLUSIONS: Being aware of the natural history of chronic gastritis, even beyond eradication of H. pylori, is important because of the associations to gastric neoplasia and ulcer disease. The blood mirror of gastroduodenal parameters showed decreased values, except for somatostatin that increased and a symptomatology with no significant changes although, morphologically determined, both inflammation and atrophy had decreased