• Javier Milara, Javier Lluch, Patricia Almudever, Jose Freire, Qian Xiaozhong, and Julio Cortijo.
• Clinical Research Unit (UIC), University General Hospital Consortium, Valencia, Spain; Department of Biotechnology, Universidad Politécnica de Valencia, Valencia, Spain; Research Foundation of General Hospital of Valencia, Valencia, Spain. Electronic address: xmilara@hotmail.com.
• J. Allergy Clin. Immunol. 2014 Aug 1; 134 (2): 314-22.

BackgroundGlucocorticoid functions are markedly impaired in patients with chronic obstructive pulmonary disease (COPD). The phosphodiesterase 4 inhibitor roflumilast N-oxide (RNO) is the active metabolite of roflumilast approved as a treatment to reduce the risk of exacerbations in patients with severe COPD.ObjectiveWe sought to characterize the differential effects of RNO versus corticosteroids and their potential additive/synergistic effect in neutrophils from patients with COPD, thus providing scientific rationale for the combination of roflumilast with corticosteroids in the clinic.MethodsPeripheral blood neutrophils were isolated from patients with COPD (n = 32), smokers (n = 7), and healthy nonsmokers (n = 25). Levels of IL-8, matrix metallopeptidase 9 (MMP-9), and biomarkers of glucocorticoid resistance were determined by using ELISA and RT-PCR. Neutrophils were incubated with dexamethasone (0.1 nmol/L to 1 μmol/L), RNO (0.1 nmol/L to 1 μmol/L), or the combination of 1 nmol/L RNO plus 10 nmol/L DEX and stimulated with LPS (1 μg/mL) or cigarette smoke extract 5%; levels of IL-8, MMP-9, and other biomarkers were measured at the end of the incubation period.ResultsPeripheral neutrophils from patients with COPD showed a primed phenotype with an increased basal release of IL-8 and MMP-9 and expressed a corticosteroid resistance molecular profile characterized by an increase in phosphoinositide 3-kinase δ, macrophage migration inhibitory factor, and glucocorticoid receptor β expression and a decrease in HDAC activity and mitogen-activated protein kinase phosphatase 1 expression. RNO demonstrated robust anti-inflammatory effects on neutrophils from patients with COPD, reversing their resistance to corticosteroids. The combination of RNO and dexamethasone showed additive/synergistic effects, which were consistent with the reversal of corticosteroid-resistant molecular markers by RNO.ConclusionRNO reverses corticosteroid resistance and shows strong anti-inflammatory effects alone or in combination with corticosteroids on neutrophils from patients with COPD.Copyright © 2014 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

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