Fluticasone, but not salmeterol, reduces cigarette smoke-induced production of interleukin-8 in human airway smooth muscle

Abstract Cigarette smoke is the leading risk factor for the development of chronic obstructive pulmonary disease. We have recently shown that cigarette smoke extract synergises with tumour necrosis factor α (TNFα) in the induction of interleukin-8 (IL-8) from human airway smooth muscle cells. We have investigated the effect of fluticasone propionate, a corticosteroid, and salmeterol, a β 2 -adrenergic receptor agonist, on cigarette smoke extract-induced IL-8 production by human airway smooth muscle cells. Human airway smooth muscle cells in primary culture were exposed to cigarette smoke extract and/or TNFα (1 ng ml −1 ) with and without pretreatment with fluticasone (10 −13 –10 −8  M) and/or salmeterol (10 −11 –10 −6  M). IL-8 was analysed by ELISA. Fluticasone dose-dependently inhibited IL-8 release induced by cigarette smoke extract, TNFα or combined cigarette smoke extract and TNFα. However, while IL-8 release in the presence of cigarette smoke extract alone was completely inhibited by fluticasone, IL-8 production induced by cigarette smoke extract and TNFα was only partially reduced. Salmeterol alone had no effect on cigarette smoke extract and/or TNFα-induced IL-8 production from human airway smooth muscle cells. Combined fluticasone and salmeterol did not cause further inhibitory effects compared to fluticasone alone. Fluticasone but not salmeterol is effective in reducing cigarette smoke extract-induced IL-8 production in human airway smooth muscle cells. The reduced inhibition of cigarette smoke extract- and TNFα-induced IL-8 release by fluticasone may explain why corticosteroids are less effective in chronic obstructive pulmonary disease where increased amounts of TNFα are present.