Do salivary organic components play a protective role in health and disease of the esophageal mucosa?

Abstract

Aggressive factors operating within the esophageal lumen during gastroesophageal reflux are balanced by adequately mobilized protective mechanisms. Esophageal mucosal protection operates at three different although complementary dimensions: (1) preepithelial, (2) epithelial and (3) postepithelial. Since aggressive factors predominantly operate within the esophageal lumen, preepithelial defense is pivotal in mucosal protection. The preepithelial barrier is significantly enhanced by the quantity and the quality of salivary organic components such as salivary mucin, nonmucin protein, salivary epidermal growth factor (EGF) and salivary prostaglandin E2. The rate of secretion of salivary mucin, nonmucin protein and EGF under the impact of intraesophageal mechanical (bolus) and chemical (HCl/pepsin) stimulation, mimicking the natural gastroesophageal reflux scenario, is significantly impaired in patients with RE, whereas the rate of salivary PGE2 output remains essentially unchanged. Salivary secretory response to esophageal mechanical and chemical stimuli in terms of organic components, mediated by the esophagosalivary reflex pathway, exhibits a significant impairment in patients with reflux esophagitis.