Neutrophil extracellular trap production and CCL4L2 expression influence corticosteroid response in asthma.

The association between neutrophil extracellular traps (NETs) and response to inhaled corticosteroids (ICS) in asthma is unclear. To better understand this relationship, we analyzed the blood transcriptomes from children with controlled and uncontrolled asthma in the Taiwanese Consortium of Childhood Asthma Study using weighted gene coexpression network analysis and pathway enrichment methods. We identified 298 uncontrolled asthma-specific differentially expressed genes and one gene module associated with neutrophil-mediated immunity, highlighting a potential role for neutrophils in uncontrolled asthma. We also found that NET abundance was associated with nonresponse to ICS in patients. In a neutrophilic airway inflammation murine model, steroid treatment could not suppress neutrophilic inflammation and airway hyperreactivity. However, NET disruption with deoxyribonuclease I (DNase I) efficiently inhibited airway hyperreactivity and inflammation. Using neutrophil-specific transcriptomic profiles, we found that CCL4L2 was associated with ICS nonresponse in asthma, which was validated in human and murine lung tissue. CCL4L2 expression was also negatively correlated with pulmonary function change after ICS treatment. In summary, steroids fail to suppress neutrophilic airway inflammation, highlighting the potential need to use alternative therapies such as leukotriene receptor antagonists or DNase I that target the neutrophil-associated phenotype. Furthermore, these results highlight CCL4L2 as a potential therapeutic target for individuals with asthma refractory to ICS.

Effect of high-flow nasal therapy during early pulmonary rehabilitation in patients with severe AECOPD: a randomized controlled study.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is airway inflammation characterized and low daily physical activity. Most pulmonary rehabilitation (PR) programs are often provided to stable patients, but fewer training programs are specific for hospitalized patients with acute exacerbation (AE). Patients with AECOPD experience increased dyspnea sensations and systemic inflammation during exercise training. High-flow nasal therapy (HFNT) reduces the minute volume, lowers the respiratory rate, and decreases the work of breathing. However, it is not clear whether HFNT is efficient during exercise training. In this study, we investigated the effects of HFNT during exercise training in an early PR program among hospitalized patients with severe AECOPD. METHODS: We enrolled COPD patients hospitalized due to AE. They were randomized into two groups according to their status into HFNT PR and non-HFNT PR groups. This study collected basic data, and also assessed a pulmonary function test, 6-min walking test, blood inflammatory biomarkers, and arterial gas analysis at the baseline, and at 4 and 12 weeks of the intervention. Data were analyzed using SPSS statistical software. RESULT: We recruited 44 AECOPD patients who completed the 12-week PR program. The HFNT PR program produced significant improvements in exercise tolerance as assessed by the 6-min walking distance (6MWD), reduced dyspnea sensations in the modified Medical Research Council (mMRC), and decreased systemic inflammation as evidenced by the a lower C-reactive protein (CRP) level. A reduction in the length of hospitalization was achieved with PR in the 1-year follow-up in the two groups. The HFNT PR group showed better trends of reduced air trapping in the delta inspiration capacity (IC) and an increased quality of life according to the COPD assessment test (CAT) than did the non-HFNT PR group. CONCLUSIONS: HFNT during exercise training in early PR increases exercise tolerance and reduces systemic inflammation in hospitalized patients with severe AECOPD.