Urates in exhaled breath condensate as a biomarker of control in childhood asthma

Exhaled Breath Condensate in Childhood Asthma: A Review and Current Perspective

Exhaled breath condensate (EBC) was introduced more than two decades ago as a novel, non-invasive tool to assess airway inflammation. This review summarizes the latest literature on the various markers in EBC to predict asthma in children. Despite many recommendations and two comprehensive Task Force reports, there is still large heterogeneity in published data. The biggest issue remains a lack of standardization regarding EBC collection, preservation, processing, and analysis. As a result, published studies show mixed or conflicting results, questioning the reproducibility of findings. A joint, multicenter research study is urgently needed to address the necessary methodological standardization.

Evolution of clinical and environmental health applications of exhaled breath research: Review of methods and instrumentation for gas-phase, condensate, and aerosols

Human breath, along with urine and blood, has long been one of the three major biological media for assessing human health and environmental exposure. In fact, the detection of odor on human breath, as described by Hippocrates in 400 BC, is considered the first analytical health assessment tool. Although less common in comparison to contemporary bio-fluids analyses, breath has become an attractive diagnostic medium as sampling is non-invasive, unlimited in timing and volume, and does not require clinical personnel. Exhaled breath, exhaled breath condensate (EBC), and exhaled breath aerosol (EBA) are different types of breath matrices used to assess human health and disease state. Over the past 20 years, breath research has made many advances in assessing health state, overcoming many of its initial challenges related to sampling and analysis. The wide variety of sampling techniques and collection devices that have been developed for these media are discussed herein. The different types of sensors and mass spectrometry instruments currently available for breath analysis are evaluated as well as emerging breath research topics, such as cytokines, security and airport surveillance, cellular respiration, and canine olfaction.

Biomarkers for severe allergic asthma in children: could they be useful to guide disease control and use of omalizumab?

INTRODUCTION

Although symptom controls in asthmatic children can be achieved through compliant use of conventional medication, some children have uncontrolled severe persistent asthma, especially if they are allergic. For these children, omalizumab (approved by the EMA and FDA in children aged > 6 years) could be a therapeutic option. However, response to omalizumab varies from one child to another. Predictive biomarkers of omalizumab effectiveness could be useful to monitor response to treatment. Area covered: The authors searched in the PubMed database for publications related to the use of biomarkers in allergic asthma. Supported by their own experience in phenotyping asthma in children, they analyzed whether these biomarkers could be useful in assessing response to omalizumab. Expert commentary: Th2 inflammation in children with allergic asthma can be assessed by measuring several biomarkers (blood eosinophil, serum ECP or periostin, FeNO). While a single measurement may be insufficient, a combination of biomarkers assessments may improve the follow-up of children treated by omalizumab.

Diagnostic Performance of Soluble Triggering Receptor Expressed on Myeloid Cells-1 in Ventilator-Associated Pneumonia of Patients with Ischemic Stroke

Objective. To investigate the effect of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in serum, bronchoalveolar lavage fluid (BALF), endotracheal aspiration (ETA), and exhaled breath condensate (EBC) samples as early biomarkers for the diagnosis of ventilator-associated pneumonia (VAP) in patients with ischemic stroke. Methods. One hundred and thirty-two patients with clinically suspected VAP were enrolled in this study. Bronchoscopy was performed on the day of clinically suspected VAP. sTREM-1 levels in serum, BALF, ETA, and EBC were measured. VAP was diagnosed by quantitative cultures of BALF (≥104 cfu/mL). Results. VAP was confirmed in 76 (57.58%) cases. Patients with VAP showed significantly higher sTREM-1 in BALF [32.35 (IQR, 30.08-41.72) versus 18.92 (11.89-31.72)] pg/mL and in EBC [1.57 (IQR, 1.02-2.61) versus 0.41 (0.19-1.61)] pg/mL than patients without VAP. The area under the curve was 0.813 (p < 0.001). The optimum cut-off value for sTREM-1 in BALF was 23.61 pg/mL, yielding sensitivity and specificity of 85.5% and 73.1%. sTREM-1 in BALF had excellent correlation with that in EBC (R2 = 0.78, p < 0.05). Conclusions. sTREM-1 in EBC and BALF had good diagnostic performance in differentiating patients with and without VAP.

Effect of Inhaled Budesonide on Interleukin-4 and Interleukin-6 in Exhaled Breath Condensate of Asthmatic Patients

Background:

Studies of interleukin (IL)-4 and IL-6 in the exhaled breath condensate (EBC) of asthmatic patients are limited. This study was to determine the effect of inhaled corticosteroid (ICS) treatment on IL-4 and IL-6 in the EBC of asthmatic patients.

Methods:

In a prospective, open-label study, budesonide 200 μg twice daily by dry powder inhaler was administered to 23 adult patients with uncontrolled asthma (mean age 42.7 years) for 12 weeks. Changes in asthma scores, lung function parameters (forced expiratory volume in 1 s [FEV₁], peak expiratory flow [PEF], forced expiratory flow at 50% of forced vital capacity [FEF₅₀], forced expiratory flow at 75% of forced vital capacity, maximum mid-expiratory flow rate) and the concentrations of IL-4 and IL-6 in EBC were measured.

Results:

Both asthma scores and lung function parameters were significantly improved by ICS treatment. The mean IL-4 concentration in the EBC was decreased gradually, from 1.92 ± 0.56 pmol/L before treatment to 1.60 ± 0.36 pmol/L after 8 weeks of treatment (P < 0.05) and 1.54 ± 0.81 pmol/L after 12 weeks of treatment (P < 0.01). However, the IL-6 concentration was not significantly decreased. The change in the IL-4 concentration was correlated with improvements in mean FEV₁, PEF and FEF₅₀ values (correlation coefficients −0.468, −0.478, and −0.426, respectively).

Conclusions:

The concentration of IL-4 in the EBC of asthmatic patients decreased gradually with ICS treatment. Measurement of IL-4 in EBC could be useful to monitor airway inflammation in asthmatics.