Ultrastructural study of antral G cells in patients with duodenal ulcer: effect of Helicobacter pylori eradication.

Abstract

It is established now that Helicobacter pylori infection is associated with exaggerated gastrin release to meals and other stimuli and that the abnormal secretion of gastrin is reversed after successful treatment of the infection. By comparing morphology of G cells from the same patients before and after treatment, we were able to investigate the ultrastructural effect of cure of H. pylori on G cells. Gastric mucosal biopsy specimens were obtained from 10 patients with duodenal ulcer before and 3, 6, and 9 months after cure of H. pylori infection. Negative controls consisted of four healthy volunteers without H. pylori infection. G cells were evaluated by immunohistochemical and electron microscopy. Treatment with H2-antagonists was continued for 6 months after cure of the H. pylori infection. Ultrastructural studies of secretory granules of antral G cells in controls displayed a broad range of electron density ranging from dark with a full appearance to totally electron-lucent with a "vacuolating" appearance. In duodenal ulcer patients before treatment, electron-lucent vacuolating granules predominated. After elimination of H. pylori, G-cell granules showed a marked increase in electron density close to that of controls. Our study showed that the density of granules of G cells is decreased in H. pylori-infected duodenal ulcer patients compared to that in H. pylori-negative controls and is consistent with enhanced gastrin release. Cure of H. pylori infection was associated with return to normal density of G-cell granules.