Role of alkaline secretion and cell restitution in duodenal mucosal protection

Duodenal alkaline secretion is a protective mechanism that is sensitive to changes in mucosal blood flow and arterial bicarbonate concentration (i.e. bicarbonate delivery to the mucosa). Alkaline secretion has been shown to prevent or limit damage and to facilitate the repair process once damage has occurred. A rapid restitution of the epithelial integrity has been demonstrated in the duodenum. This repair process is sensitive to alterations in nutrient HCO3- supply. Removal of the necrotic cell layer before repair is complete inhibits the re-establishment of epithelial continuity at low luminal pH. However, under optimal conditions repair is completed within a few hours, even with repeated acid challenge.