OBJECTIVE: To investigate the relationship between Helicobacter pylori and gastric mucosa in control and duodenal ulcer patients at the electron microscopic level.

METHODS: Three antral biopsies were taken from each of 20 normal control volunteers and 30 duodenal ulcer patients presented to the gastroenterology unit at Jordan University Hospital for upper endoscopic examination. Each specimen was fixed and processed for electron microscopic study.

RESULTS: Two types of Helicobacter pylori were observed and identified by their morphology at electron microscopy. The first one was characterized by double external smooth membranes and homogeneous cytoplasmic contents, and the second type with a characteristic ring-shaped intracytoplasmic vacuole. Electron microscopic examination of normal controls showed normal gastric mucosa and a small number of Helicobacter pylori in 12 out of 20 controls. However, in duodenal ulcer patients, 5 different patterns of interaction between the Helicobacter pylori and gastric mucosa were observed in relation to the severity of the disease. In duodenal ulcer patients, various types of epithelial damage was seen accompanied with a decrease or absence of mucous secretion and with more colonization of bacteria.

CONCLUSION: The morphology and pathogenesis of Helicobacter pylori was described in duodenal ulcer patients, and 5 different patterns of contact between Helicobacter pylori and surface epithelium were recognized causing variable degrees of microvillous atrophy and reduced mucous secretion. The vacuolated type of Helicobacter pylori was more adherent to the damaged epithelium and there was a direct relationship between the epithelial damage and bacterial load. In the normal controls, no epithelial damage and scanty bacteria were observed. The various types of epithelial changes of gastric mucosa has initiated more research at electron microscopic level on the immune mechanism of the gastric mucosa to determine the underlying cause of the varying severity of the disease.

Institution
Faculty of Medicine, Department of Anatomy and Histology, University of Jordan, Amman, 11942, Jordan.