Esophageal epithelial defense against acid injury.

The esophagus is lined with a stratified squamous epithelium. This epithelium, like that of stomach and duodenum, is able to resist damage even on continuous exposure to luminal acid. The intrinsic epithelial defenses against acid injury in the esophagus can be labeled "tissue resistance." Tissue resistance is not a single factor but a number of structural and functional elements within the epithelium that interact in a dynamic way to provide protection. This article enumerates the components of this epithelial defense system and describes their roles in the protective process. Furthermore, the ability of agents such as indomethacin and sucralfate to provide protection against acid injury to esophageal epithelium is discussed in light of their known actions at the tissue level.