Breath tests cover the fraction of nitric oxide in expired gas (F_ENO), volatile organic compounds (VOCs), variables in exhaled breath condensate (EBC) and other measurements. For EBC and forF_ENO, official recommendations for standardised procedures are more than 10 years old and there is none for exhaled VOCs and particles. The aim of this document is to provide technical standards and recommendations for sample collection and analytic approaches and to highlight future research priorities in the field. For EBC andF_ENO, new developments and advances in technology have been evaluated in the current document. This report is not intended to provide clinical guidance on disease diagnosis and management.Clinicians and researchers with expertise in exhaled biomarkers were invited to participate. Published studies regarding methodology of breath tests were selected, discussed and evaluated in a consensus-based manner by the Task Force members.Recommendations for standardisation of sampling, analysing and reporting of data and suggestions for research to cover gaps in the evidence have been created and summarised.Application of breath biomarker measurement in a standardised manner will provide comparable results, thereby facilitating the potential use of these biomarkers in clinical practice.

Context: Electronic cigarettes (e-cigarettes) are becoming increasingly popular yet their effects on health remain unknown. Objective: To conduct the first comprehensive and standardized assessment of the acute impact of active and passive e-cigarette smoking on serum cotinine and lung function, as compared to active and passive tobacco cigarette smoking. Materials and methods: Fifteen smokers (≥15 cigarettes/day; seven females; eight males) and 15 never-smokers (seven females; eight males) completed this repeated-measures controlled study. Smokers underwent a control session, an active tobacco cigarette (their favorite brand) smoking session and an active e-cigarette smoking session. Never-smokers underwent a control session, a passive tobacco cigarette smoking session and a passive e-cigarette smoking session. Serum cotinine, lung function, exhaled carbon monoxide and nitric oxide were assessed. The level of significance was set at p ≤ 0.001 to adjust for multiple comparisons. Results: e-Cigarettes and tobacco cigarettes generated similar (p > 0.001) effects on serum cotinine levels after active (60.6 ± 34.3 versus 61.3 ± 36.6 ng/ml) and passive (2.4 ± 0.9 versus 2.6 ± 0.6 ng/ml) smoking. Neither a brief session of active e-cigarette smoking (indicative: 3% reduction in FEV1/FVC) nor a 1 h passive e-cigarette smoking (indicative: 2.3% reduction in FEV1/FVC) significantly affected the lung function (p > 0.001). In contrast, active (indicative: 7.2% reduction in FEV1/FVC; p < 0.001) but not passive (indicative: 3.4% reduction in FEV1/FVC; p = 0.005) tobacco cigarette smoking undermined lung function. Conclusion: Regarding short-term usage, the studied e-cigarettes generate smaller changes in lung function but similar nicotinergic impact to tobacco cigarettes. Future research should target the health effects of long-term e-cigarette usage, including the effects of nicotine dosage.

Endogenous airway acidification, as assessed by pH in expired breath condensate, has been implicated in asthma pathophysiology. We measured pH in breath condensate of patients with inflammatory airway diseases in stable condition and examined its relationship with the inflammatory process (as assessed by differential cell counts in induced sputum), oxidative stress (as assessed by H₂O₂ and 8-isoprostane), and nitric oxide metabolism (as assessed by total nitrate/nitrite). We studied 40 patients with bronchial asthma (20 with moderate disease, forced expiratory volume in 1 second 60 [10]% SD predicted), 20 patients with bronchiectasis, 20 patients with chronic obstructive pulmonary disease (COPD), and 10 normal subjects. Mean (95% confidence intervals) pH values were significantly lower in patients with COPD and bronchiectasis compared with patients with asthma and control subjects (7.16, 7.09–7.23 and 7.11, 7.04–7.19 versus 7.43, 7.35–7.52 and 7.57, 7.51–7.64, respectively, p < 0.0001). Patients with moderate asthma had significantly lower values compared with mild and control subjects. In patients with COPD and bronchiectasis, the values of pH were significantly correlated with both sputum neutrophilia and oxidative stress. Respectively, in patients with moderate asthma, a significant correlation was observed between pH and sputum eosinophilia, total nitrate/nitrite, and oxidative stress. The pH of the expired breath condensate might be a simple, noninvasive, inexpensive, and easily repeatable procedure for the evaluation of the inflammatory process in airway diseases.

Rationale: There are no studies on withdrawal of inhaled corticosteroids in patients on long-term triple therapy in the absence of frequent exacerbations. Objectives: To evaluate the efficacy and safety of direct de-escalation from long-term triple therapy to indacaterol/glycopyrronium in nonfrequently exacerbating patients with chronic obstructive pulmonary disease (COPD). Methods: This 26-week, randomized, double-blind, triple-dummy study assessed the direct change from long-term triple therapy to indacaterol/glycopyrronium (110/50 μg once daily) or continuation of triple therapy (tiotropium [18 μg] once daily plus combination of salmeterol/fluticasone propionate [50/500 μg] twice daily) in nonfrequently exacerbating patients with moderate-to-severe COPD. Primary endpoint was noninferiority on change from baseline in trough FEV1. Moderate or severe exacerbations were predefined secondary endpoints. Measurements and Main Results: A total of 527 patients were randomized to indacaterol/glycopyrronium and 526 to triple therapy. Inhaled corticosteroids withdrawal led to a reduction in trough FEV1 of −26 ml (95% confidence interval, −53 to 1 ml) with confidence limits exceeding the noninferiority margin of −50 ml. The annualized rate of moderate or severe COPD exacerbations did not differ between treatments (rate ratio, 1.08; 95% confidence interval, 0.83 to 1.40). Patients with ≥300 blood eosinophils/μl at baseline presented greater lung function loss and higher exacerbation risk. Adverse events were similar in the two groups. Conclusions: In patients with COPD without frequent exacerbations on long-term triple therapy, the direct de-escalation to indacaterol/glycopyrronium led to a small decrease in lung function, with no difference in exacerbations. The higher exacerbation risk in patients with ≥300 blood eosinophils/μl suggests that these patients are likely to benefit from triple therapy. Clinical trial registered with www.clinicaltrials.gov (NCT 02603393).

Nicotine, the primary addictive substance in tobacco, is widely abused. Relapse to cues associated with nicotine results in increased glutamate release within nucleus accumbens core (NAcore), modifying synaptic plasticity of medium spiny neurons (MSNs) which contributes to reinstatement of nicotine seeking. However, the role of cholinergic interneurons (ChIs) within the NAcore in mediating these neurobehavioral processes in unknown. ChIs represent less than 1% of the accumbens neuronal population yet are activated during drug seeking and reward-predicting events. Thus, we hypothesized that ChIs may play a significant role in mediating glutamatergic plasticity that underlies nicotine seeking behavior. Using chemogenetics transgenic rats that express Cre under the control of the choline acetyltransferase (ChAT) promoter, ChIs were bi-directionally manipulated prior to cue-induced reinstatement. Following nicotine self-administration and extinction training, ChIs were activated or inhibited prior to a cue reinstatement session. Following reinstatement, whole-cell electrophysiology from NAcore MSNs was used to assess changes in plasticity, measured via α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) / N-Methyl-D-Aspartate (NMDA) (A/N) ratios. Chemogenetic inhibition of ChIs inhibited cued nicotine seeking and resulted in decreased A/N, whereas activation of ChIs had no effect, demonstrating that ChI inhibition prevents transient synaptic potentiation (t-SP) associated with cue-induced nicotine seeking. To assess potential underlying mechanisms, accumbens α₄β₂- and α₇-containing nicotinic ACh receptors (nAChRs) were pharmacologically inhibited and MSN synaptic morphology was assessed following reinstatement. Inhibition of both nAChR subtypes prevented cue-induced nicotine seeking and t-SP (measured via changes in spine head diameter). Together, these results demonstrate that these neurons mediate cue-induced nicotine reinstatement and underlying synaptic plasticity within the NAcore.