PHYSIOLOGY AND PATHOPHYSIOLOGY OF APOPTOSIS IN EPITHELIAL-CELLS OF THE LIVER, PANCREAS, AND INTESTINE

Cell death of gastrointestinal epithelial cells occurs by a process re ferred to as apoptosis. In this review, we succinctly define apoptosis and summarize the role of apoptosis in the physiology and pathophysio logy of epithelial cells in the liver, pancreas, and small and large i ntestine. The physiological mediators regulating apoptosis in gastroin testinal epithelial cells, when known, are discussed. Selected pathoph ysiological consequences of excessive apoptosis and inhibition of apop tosis are used to illustrate the significance of apoptosis in disease processes. These examples demonstrate that excessive apoptosis may res ult in epithelial cell atrophy, injury, and dysfunction, whereas inhib ition of apoptosis results in hyperplasia and promotes malignant trans formation. The specific cellular mechanisms responsible for dysregulat ion of epithelial cell apoptosis during pathophysiological disturbance s are emphasized. Potential future areas of physiological research reg arding apoptosis in gastrointestinal epithelia are highlighted when ap propriate.