Can Helicobacter pylori invade human gastric mucosa?: an in vivo study using electron microscopy, immunohistochemical methods, and real-time polymerase chain reaction.

Unlabelled: BACKGROUND-GOALS: We used transmission electron microscopy and immunohistochemistry (IHC) to investigate how Helicobacter pylori affects the gastric mucosa of humans.

Study: Gastric biopsy specimens were obtained from 15 patients with gastric discomfort. The samples were processed using both microscopic examinations and a real-time polymerase chain reaction to detect H. pylori DNA. IHC staining was performed with an avidin-biotin complex immunoperoxidase kit for paraffin-embedded tissue sections. Polyclonal rabbit anti-H. pylori was used as a primary antibody.

Results: IHC-applied slides with brown-stained spiral bacteria on the luminal surface and in the intercellular spaces of the gastric epithelium; electron-dense spiral H. pylori of approximately 200 to 300 nm in diameter both in the gastric lumen and between the gastric epithelial cells; coccoid or ellipsoid H. pylori attached to the epithelial cells through egg-cup-like pedestals; coccoid H. pylori within the endocytotic vesicles in the apical cytoplasmic part of the epithelial cells, thus suggesting their internalization by phagocytosis; electron-dense spiral H. pylori within the membrane-bounded vacuoles of both the gastric epithelial cells, and the lamina propria; a prominent vacuolization of gastric epithelial cells invaded by H. pylori; and swollen and lytic gastric epithelial cells that suggest a mucosal erosion and may lead to peptic ulcer. All of these microscopic findings were not present in the H. pylori DNA-negative specimens that were used as the control group.

Conclusion: This is the first histomicrobiologic study to show gastric cells invaded by H. pylori in patients with H. pylori infection confirmed by real-time polymerase chain reaction.