Gastroduodenal mucosal defense

Purpose of review We have summarized recent findings related to gastroduodenal mucosal defense as well as factors contributing to defensive failure, highlighting findings that illuminate new pathophysiological mechanisms. Recent findings Gastroduodenal bicarbonate secretion is mediated by prostaglandin E receptors and stimulated by the prostone lubiprostone. Toll-like receptor (TLR)4 signaling is protective against gastric injury. Intestinal alkaline phosphatase (IAP) is a chemosensor that regulates the duodenal mucosal surface pH. Lipopolysaccharide (LPS) increases gastric permeability; IAP secreted during fat digestion may detoxify colonic LPS. NADPH oxidase activity mediates ischemia/reperfusion-related gastric mucosal damage. Heat shock protein 70 (HSP70) protects the gastric mucosa through inhibition of apoptosis, proinflammatory cytokines, and cell adhesion molecules (CAMs). HSP90 may be a contributing factor in impaired adaptive cytoprotection. Proteinase-activated receptor-1 (PAR-1) is protective against Helicobacter-induced gastritis, mediated by the suppression of proinflammatory pathways. IKK beta/NF-kappa B signaling decreases chronic Helicobacter-induced inflammation by inhibiting cellular apoptosis and necrosis. Activation of A(2A) adenosine receptors decreases inflammation and gastritis but leads to persistent Helicobacter pylori infection. Summary Enhanced understanding of the mechanisms of gastroduodenal defense and injury provides new insight into potential therapeutic targets, contributing towards the development of better tolerated and more effective therapies.