Effect of formoterol and salmeterol on IL-6 and IL-8 release in airway epithelial cells

Beta(2)-adrenoceptors are widely distributed and occur on airway epithelial cells. The aim of this study was to find out whether the two long-acting beta(2)-agonists formoterol and salmeterol influence interleukin-6 (IL-6) and -8 (IL-8) release from airway epithelial cells in vitro. A549 cells and primary bronchial epithelial cells (PBEC) were stimulated with organic dust from pig barns. Non-stimulated and dust-stimulated cells were incubated for 24h with formoterol or salmeterol (10(-13)-10(-6)M) and the release of IL-6 and IL-8 into the medium was assessed by ELISA technique. Propranolol (10(-5)M) or sotalol (10(-3)M) were used to block the beta(2)-agonist mediated effects. Formoterol and salmeterol both induced enhancement of IL-6 and IL-8 release and added to the effect of organic dust. This enhanced release was blocked by a beta-blocker in PBEC but not in A549 cells. To our knowledge, this is the first time beta(2)-agonists have been shown to stimulate IL-6 release from airway epithelial cells. The results indicate different mechanisms of beta(2)-agonist action in bronchial and alveolar epithelial cells. Furthermore, our results indicate that A549 cells do not possess functional beta(2)-adrenoceptors.