Eradication of Helicobacter pylori and gastrin-somatostatin link in duodenal ulcer patients.

Helicobacter pylori (Hp) infection may be associated with duodenal ulcer (DU) and accompanied by increased release of gastrin and deficiency of somatostatin (S-S) but the mechanisms of these changes in DU patients after eradication of Hp have been little studied. Cholecystokinin (CCK) has been implicated in the feedback control of gastric acid secretion in healthy subjects but its contribution to secretory disorders in DU patients has been little examined. This study, therefore, investigated whether CCK participates in the impairment of postprandial gastrin release and gastric acid secretion in active DU patients. Tests were undertaken in 10 DU patients without or with elimination of the action of endogenous CCK using loxiglumide (LOX), a selective CCK-A receptor antagonist, before and 4 wk. after eradication of Hp with triple therapy (omeprazole, amoxycillin and bismuth). In Hp positive DU patients, the postprandial acid secretion (measured by continuous intragastric pH monitoring) was accompanied by a pronounced increment in plasma gastrin with negligible increase of intraluminal release of S-S. The administration of LOX in these patients did not affect significantly the postprandial pH profile and the rise in plasma gastrin. After eradication of Hp the median postprandial intragastric pH increased to about 4.3 (compared to 3.5 before the Hp eradication); the postprandial gastrin concentration was reduced by about 40%, while luminal release of S-S was increased 2 folds. The administration of LOX resulted in significantly greater decrease in median pH (3.1) and higher rise in postprandial plasma gastrin in these patients. Also the postprandial plasma S-S showed a small, but significant decline (by about 25%) as compared to that in placebo treated patients. This study provides evidence that: (1) Hp infection in DU patients is accompanied by enhanced gastrin release and the reduction in luminal release of S-S; (2) The failure of LOX to affect gastric secretion and plasma gastrin DU Hp infected patients could be attributed, at least in part, to the failure of endogenous CCK to control gastric acid secretion via release of S-S; (3) Hp infected patients appear to exhibit a deficiency of S-S release that can be reversed by the eradication of Hp indicating that both peptides may contribute to the acceleration of the ulcer healing following Hp eradication in DU patients; (4) The test with LOX and gastric luminal S-S assay may be useful in identification of Hp positive DU patients with CCK-mediated impaired feedback control of gastric secretion and deficiency of S-S caused by Hp infection.