EPITHELIAL FACTORS - MODULATION OF THE AIRWAY SMOOTH-MUSCLE TONE

The airway epithelium is composed of a heterogeneous population of cel ls. This epithelial layer is not only a physical barrier but also a ta rget responding to a variety of inflammatory mediators. These cells ca n respond by releasing contracting and relaxing factors to modulate ai rway responsiveness. They can also metabolize some of the inflammatory mediators. Epithelial damage is a consistent feature of some respirat ory conditions, but whether or not such damage contributes to airway d isease is for the moment unknown. This review summarizes the literatur e on the known and proposed roles of the epithelium in the modulation of the airway smooth muscle tone.