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Abstract: Interleukin-17A (IL-17A), cigarette smoke and oxidative/nitrosative stress are involved in inflammatory airway diseases, and the mechanisms behind these processes are still poorly understood. We investigated whether recombinant human IL-17A (rhIL-17A), in combination with cigarette smoke extracts (CSE), increases the levels of inducibile nitric oxide synthase (iNOS), reactive oxygen species, nitrotyrosine (NT) and the activation of signal transducer and activator of transcription 1 (STAT-1) in normal human bronchial epithelial cells (16HBE). The effect of beclomethasone dipropionate (BDP), formoterol and their combination was also evaluated. We demonstrated that rhIL-17A or CSE alone increases iNOS expression, reactive oxygen species and NT production and STAT-1 downstream signalling activation in terms of STAT-1ser727 and STAT-1tyr701 phosphorylation. The combination of both stimuli further increased iNOS, ROS, NT and STAT-1ser727 phosphorylation. The silencing of STAT-1 expression partially reduced the levels of iNOS, reactive oxygen species and NT generated by rhIL-17A and inhibited the effect of CSE alone in 16HBE cells. The treatment of the cells with the MEK1/2 inhibitor U0126 (1,4-diamino-2,3-dicyano-1,4-bis (o-aminophenylmercapto butadiene) abolished the expression of iNOS and STAT-1ser727 phosphorylation generated by rhIL-17A. 16HBE treated with BDP or formoterol alone partially suppressed the effect of IL-17A or CSE on ROS, NT, and STAT-1 activation. Furthermore the use of the drugs in combination showed an additive effect in 16HBE. Our findings demonstrate that IL-17A increases oxidative/nitrosative markers, likely via ERK1/2 downstream signalling and STAT-1 pathway activation in human bronchial epithelial cells. BDP and formoterol treatment reduces this effect showing an additive effect used in combination. [Copyright &y& Elsevier]

Background: Treatment guidelines recommend the regular use of inhaled corticosteroids for patients with mild persistent asthma. We investigated whether the symptom-driven use of a combination of beclomethasone dipropionate and albuterol (also known as salbutamol) in a single inhaler would be as effective as the regular use of inhaled beclomethasone and superior to the as-needed use of inhaled albuterol. Methods: We conducted a 6-month, double-blind, double-dummy, randomized, parallel-group trial. After a 4-week run-in, patients with mild asthma were randomly assigned to receive one of four inhaled treatments: placebo twice daily plus 250 μg of beclomethasone and 100 μg of albuterol in a single inhaler as needed (as-needed combination therapy); placebo twice daily plus 100 μg of albuterol as needed (as-needed albuterol therapy); 250 μg of beclomethasone twice daily and 100 μg of albuterol as needed (regular beclomethasone therapy); or 250 μg of beclomethasone and 100 μg of albuterol in a single inhaler twice daily plus 100 μg of albuterol as needed (regular combination therapy). The primary outcome was the morning peak expiratory flow rate. Results: In 455 patients with mild asthma who had a forced expiratory volume in 1 second of 2.96 liters (88.36% of the predicted value), the morning peak expiratory flow rate during the last 2 weeks of the 6-month treatment was higher (P=0.04) and the number of exacerbations during the 6-month treatment was lower (P=0.002) in the as-needed combination therapy group than in the as-needed albuterol therapy group, but the values in the as-needed combination therapy group were not significantly different from those in the groups receiving regular beclomethasone therapy or regular combination therapy. The cumulative dose of inhaled beclomethasone was lower in the as-needed combination therapy group than in the groups receiving regular beclomethasone therapy or regular combination therapy (P<0.001 for both comparisons). Conclusions: In patients with mild asthma, the symptom-driven use of inhaled beclomethasone (250 μg) and albuterol (100 μg) in a single inhaler is as effective as regular use of inhaled beclomethasone (250 μg twice daily) and is associated with a lower 6-month cumulative dose of the inhaled corticosteroid. (ClinicalTrials.gov number, NCT00382889.) N Engl J Med 2007;356:2040-52. [ABSTRACT FROM AUTHOR]