The length of the Barrett's mucosa in baboons, revisited.

Abstract

BACKGROUND: Chewing of regurgitated food with rumination elicits, gastroesophageal reflux (GER) in baboons. Protracted reflux transforms the distal multilayered squamous cell-lined epithelium into columnar-lined mucosa, with mucus-producing glands having interspersed oxyntic glands. In humans, this histological constellation is called Barrett's mucosa type 2 (BMT2). MATERIALS AND METHODS: The distal esophagus together with the proximal stomach was removed en bloc, at autopsy, from 35 adult baboons. Longitudinal sections were stained with toluidine blue, a stain that permits easy discrimination between parietal and chief gastric glands. Using a calibrated ocular scale, the length of the BMT2 was assessed in all 35 baboons. RESULTS: The mean length of the BMT2 was 9.80 mm (range 1.0 mm-40.2 mm). CONCLUSION: BMT2 in baboons is an integrated part of the natural phenomenon of mucosal adaptation to daily regurgitation of gastric acid into the distal esophagus (natural GER), whereas BMT2 in humans might reflect an evolutionary atavism in the esophagus, triggered by a non-physiological disorder (pathological GER). The baboon offers a suitable model to monitor the series of histological events that take place in the distal esophagus under the influence of protracted GER.