Changes in the morphology of villar epithelial cells adjacent to duodenal ulcers during the process of healing.

Fifteen patients with active duodenal ulcers were treated for 6 weeks with ulcerone, aluminium sucrose sulphate, or bromazepam to promote healing. Biopsies taken from the edge of ulcers before treatment showed an epithelium exclusively populated with cells of a mucus-secreting type which resembled those normally found in the gastric antrum. Biopsies taken at endoscopy from the edge of ulcers or scars at time intervals during treatment to endoscopic healing showed, irrespective of the drug used, a sequence of ultrastructural changes in villar epithelial cells, from a gastric secretory to a duodenal absorptive cell type. We suggest that the gastric cells in the duodenum are derived from stem cells in the crypts of Lieberkühn surrounding an ulcer and are produced in response to luminal fluids of abnormally low pH. Their function is probably protective, in that they isolate regions of ulceration from the healthy mucosa and, by the continuous secretion of gastric mucin, protect the ulcer from the harmful effects of luminal acids. Their transformation to absorptive cells during ulcer healing is part of a natural sequence that is aided by, but not dependent on, drug therapy.