Regeneration of esophageal epithelium in the presence of gastroesophageal reflux.

The esophageal mucosa in twelve dogs was excised from the distal third of the esophagus together with a surgical procedure to provoke gastroesophageal reflux. A longitudinal segment containing all the layers of the wall of the esophagogastric junction was removed intraoperatively in all dogs. It was determined that in this segment, the transition of the columnar and squamous epithelia and the apex of the inferior sphincter of the esophagus, which is perfectly individualized in the dog except for few variations, were at the same level. During the postoperative period, the dogs were randomly divided into two groups according to the time of sacrifice. Group I was killed after 30 days and Group II after 60. Serial sections of the autopsy specimen were taken at the level of the esophagogastric junction, in order to determine the way in which the esophageal epithelium regenerates in the presence of gastroesophageal reflux. The apex of the inferior sphincter of the esophagus was used as a fixed parameter of the esophagogastric transition, even in the absence of its epithelial lining. Postoperatively the dogs presented varying lengths of the inferior third of the esophagus relined with columnar epithelium. The epithelium originates either from the gastric epithelium itself, or from the ducts of the submucosal glands of the esophagus. The histologic aspect of the regenerated columnar epithelium varied from simple columnar epithelium to a well-differentiated epithelium resembling gastric mucosa. These studies reinforce the concept that columnar epithelium lining the terminal esophagus may be acquired due to reepithelization in an acid medium, of a previously injured esophageal epithelium.