Comparison of the effects of two long-acting beta2-agonists on cytokine secretion by human airway epithelial cells.

BACKGROUND AND PURPOSE

Long-acting beta2-agonists (LABAs) have proved to be useful in the management of asthma and prevention of exacerbations. LABAs can modulate inflammatory and repair processes in the airways of individuals affected by many respiratory disorders. This study assessed the effects of LABAs on the release of inflammatory mediators by bronchial epithelia.

METHODS

The effects of the LABAs salmeterol and formoterol on the synthesis of soluble interleukin-8 (IL-8), granulocyte-macrophage colony-stimulating factor (GM-CSF), and vascular endothelial growth factor (VEGF) in the human airway epithelial cell line A549 was investigated in vitro. Cells cultured for 8 h in the presence of an LABA were stimulated with tumor necrosis factor-alpha for 16 h and then enzyme-linked immunosorbent assays for IL-8, GM-CSF, and VEGF were performed on the supernatants.

RESULTS

Both salmeterol and formoterol significantly suppressed IL-8, GM-CSF, and VEGF secretion from tumor necrosis factor-alpha-stimulated A549 cells. Results indicated that formoterol was more potent than salmeterol in suppressing IL-8 and VEGF production. In contrast, salmeterol appeared to be more potent than formoterol in suppressing GM-CSF production.

CONCLUSION

LABAs have some anti-inflammatory effects on bronchial epithelia. The differences between salmeterol and formoterol and mechanisms for the observed effects need further evaluation.