Electron microscopic study on the regenerating epithelium of the chronic gastric ulcer.

Specimens from 31 cases of human gastric ulcers and 3 ulcer scars obtained at surgery were studied by transmission and scanning electron microscopy. A layer of simple cuboidal epithelial cells arising at the margin of the gastric ulcer migrated toward the ulcer base. Two types of regenerating epithelium (RE) were found: gastric and intestinal cell types. The gastric cell type RE originated from the gastric epithelium and was composed of immature cells which later matured to form primitive gastric glands. The intestinal cell type RE migrated from the intestinal metaplasia bordering the ulcer and contained immature cells which developed into absorptive and goblet cells forming primitive crypts and villi. In both types of RE, the basal lamina was frequently lacking. Moreover, degeneration and necrosis were often seen, especially in severe inflammatory focus. Profiles of Helicobacter pylori were observed in the gastric lumen, on the gastric type RE in about one third of the cases, but they were never found on the intestinal type RE.