Gastroduodenal mucosal defense

The gastroduodenal mucosa is a model system of defense with several structu ral levels and biologic strategies that are closely interrelated with each other to cope with the harmful ingredients of ingested food and the potenti ally deleterious effects of gastric acid and pepsin, Experimental and clini cal research carried out during the review period added to the understandin g of each component of the multiple mechanisms of gastroduodenal mucosal pr otection. In the first place, mucosal integrity is defended by the mucus ge l barrier, the epithelial cell barrier, and the immune barrier. The propert ies of these barriers are maintained by adequate regulation of mucus produc tion, bicarbonate secretion, mucosal microcirculation, and motor activity. These regulatory systems are alarmed by nociceptive neurons and the mucosal immune system which includes chemokine-secreting epithelial cells. The ult imate defense system is rapid repair of the injured mucosa under the contro l of several growth factors. Progressing insight into the network of mucosa l defense not only will improve existing therapies of inflammation and ulce ration but also will provide new leads for the management of functional dis eases in the gastroduodenal region. (C) 2000 Lippincott Williams & Wilkins, Inc.