Gastritis and hypergastrinemia due to Acinetobacter lwoffii in mice

In mouse models and humans, Helicobacter pylori is associated with an increase in serum gastrin and gastrin-expressing (G) cells with a concomitant decrease in somatostatin-expressing D cells. Inflammation of the gastric mucosa can progress to metaplastic changes in the stomach and to decreased colonization by H. pylori and increased colonization by non-H. pylori organisms. In addition, about 20% of individuals with chronic gastritis are H. pylori negative, suggesting that other organisms may induce gastritis. Consistent with this hypothesis, we report here that Acinetobacter lwoffii causes the same histologic changes as does H. pylori. Gastric epithelial cells were isolated from the entire stomach by an enzymatic method for quantitation by both flow cytometry and morphometric analysis. Two months after mice were inoculated with H. pylori or A. lwoffii, the mucosal T- and B-cell numbers significantly increased. After 4 months of infection, there was a threefold increase in the number of G cells and a doubling in the number of parietal cells. A threefold decrease in the number of D cells occurred in H. pylori- and A. lwoffii-infected mice. Plasma gastrin levels increased after both H. pylori and A. lwoffii infection. Histology revealed the presence of inflammation in the gastric mucosa with both A. lwoffii and H. pylori infection. A periodic acid-Schiff stain-alcian blue stain revealed mucous gland metaplasia of the corpus. Collectively, the results demonstrate that gastritis and hypergastrinemia are not specific for H. pylori but can be induced by other gram-negative bacteria capable of infecting the mouse stomach.