Exhaled nitric oxide and biomarkers in exhaled breath condensate indicate the presence, severity and control of childhood asthma

Surface-Enhanced Raman Spectroscopy for Nitrite Detection

Nitrite is an important chemical intermediate in the nitrogen cycle and is ubiquitously present in environmental and biological systems as a metabolite or additive in the agricultural and food industries. However, nitrite can also be toxic in excessive concentrations. As such, the development of quick, sensitive, and portable assays for its measurement is desirable. In this review, we summarize the working principles and applications of surface-enhanced Raman spectroscopy (SERS) as a rapid, portable, and ultrasensitive method for nitrite detection and showcase its applicability in various water, food, and biological samples. The challenges and opportunities for future developments are also discussed.

In Situ Collection and SERS Detection of Nitrite in Exhalations on Facemasks Based on Wettability Differences

As one of the common carriers of biological information, along with human urine specimens and blood, exhaled breath condensate (EBC) carries reliable and rich information about the body's metabolism to track human physiological normal/abnormal states and environmental exposures. What is more, EBC has gained extensive attention because of the convenient and nondestructive sampling. Facemasks, which act as a physical filter barrier between human exhaled breath and inhaled substances from the external environment, are safe, noninvasive, and economic devices for direct sampling of human exhaled breath and inhaled substances. Inspired by the ability of fog collection of Namib desert beetle, a strategy for in situ collecting and detecting EBC with surface-enhanced Raman scattering is illustrated. Based on the intrinsic and unique wettability differences between the squares and the surrounding area of the pattern on facemasks, the hydrophilic squares can capture exhaled droplets and spontaneously enrich the analytes and silver nanocubes (AgNCs), resulting in good repeatability in situ detection. Using R6G as the probe molecule, the minimal detectable concentration can reach as low as 10-16 M, and the relative standard deviation is less than 7%. This proves that this strategy can achieve high detection sensitivity and high detection repeatability. Meanwhile, this strategy is applicable for portable nitrite analysis in EBC and may provide an inspiration for monitoring other biomarkers in EBC.

The Role of Exhaled Breath Condensate in Chronic Inflammatory and Neoplastic Diseases of the Respiratory Tract

Asthma and chronic obstructive pulmonary disease (COPD) are among the most common chronic respiratory diseases. Chronic inflammation of the airways leads to an increased production of inflammatory markers by the effector cells of the respiratory tract and lung tissue. These biomarkers allow the assessment of physiological and pathological processes and responses to therapeutic interventions. Lung cancer, which is characterized by high mortality, is one of the most frequently diagnosed cancers worldwide. Current screening methods and tissue biopsies have limitations that highlight the need for rapid diagnosis, patient differentiation, and effective management and monitoring. One promising non-invasive diagnostic method for respiratory diseases is the assessment of exhaled breath condensate (EBC). EBC contains a mixture of volatile and non-volatile biomarkers such as cytokines, leukotrienes, oxidative stress markers, and molecular biomarkers, providing significant information about inflammatory and neoplastic states in the lungs. This article summarizes the research on the application and development of EBC assessment in diagnosing and monitoring respiratory diseases, focusing on asthma, COPD, and lung cancer. The process of collecting condensate, potential issues, and selected groups of markers for detailed disease assessment in the future are discussed. Further research may contribute to the development of more precise and personalized diagnostic and treatment methods.

Biomarkers in exhaled breath condensate as fingerprints of asthma, chronic obstructive pulmonary disease and asthma-chronic obstructive pulmonary disease overlap: a critical review

Asthma, chronic obstructive pulmonary disease (COPD) and asthma-COPD overlap are the third leading cause of mortality around the world. They share some common features, which can lead to misdiagnosis. To properly manage these conditions, reliable markers for early and accurate diagnosis are needed. Over the past 20 years, many molecules have been investigated in the exhaled breath condensate to better understand inflammation pathways and mechanisms related to these disorders. Recently, more advanced techniques, such as sensitive metabolomic and proteomic profiling, have been used to obtain a more comprehensive understanding. This article reviews the use of targeted and untargeted metabolomic methodology to study asthma, COPD and asthma-COPD overlap.

Identification of Hub Genes and Potential Biomarkers for Childhood Asthma by Utilizing an Established Bioinformatic Analysis Approach

Childhood asthma represents a heterogeneous disease resulting from the interaction between genetic factors and environmental exposures. Currently, finding reliable biomarkers is necessary for the clinical management of childhood asthma. However, only a few biomarkers are being used in clinical practice in the pediatric population. In the long run, new biomarkers for asthma in children are required and would help direct therapy approaches. This study aims to identify potential childhood asthma biomarkers using a genetic-driven biomarkers approach. Herein, childhood asthma-associated Single Nucleotide Polymorphisms (SNPs) were utilized from the GWAS database to drive and facilitate the biomarker of childhood asthma. We uncovered 466 childhood asthma-associated loci by extending to proximal SNPs based on r2 > 0.8 in Asian populations and utilizing HaploReg version 4.1 to determine 393 childhood asthma risk genes. Next, the functional roles of these genes were subsequently investigated using Gene Ontology (GO) term enrichment analysis, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and a protein−protein interaction (PPI) network. MCODE and CytoHubba are two Cytoscape plugins utilized to find biomarker genes from functional networks created using childhood asthma risk genes. Intriguingly, 10 hub genes (IL6, IL4, IL2, IL13, PTPRC, IL5, IL33, TBX21, IL2RA, and STAT6) were successfully identified and may have been identified to play a potential role in the pathogenesis of childhood asthma. Among 10 hub genes, we strongly suggest IL6 and IL4 as prospective childhood asthma biomarkers since both of these biomarkers achieved a high systemic score in Cytohubba’s MCC algorithm. In summary, this study offers a valuable genetic-driven biomarker approach to facilitate the potential biomarkers for asthma in children.

Registered human trials addressing environmental and occupational toxicant exposures: Scoping review of immunological markers and protective strategies

Exposure to pollution is a worldwide societal challenge participating in the etiology and progression of different diseases. However, the scarce information hinders our understanding of the actual level of human exposure and its specific effects. Inadequate and excessive immune responses underlie diverse chronic diseases. Yet, it is unclear which and how toxicant exposures affect the immune system functions. There is a multiplicity of immunological outcomes and biomarkers being studied in human trials related to exposure to different toxicants but still without clear evidence of their value as biomarkers of exposure or effect. The main aim of this study was to collect scientific evidence and identify relevant immunological biomarkers used at the clinical level for toxicant exposures. We used the platform clinical trials.gov as a database tool. First, we performed a search combining research items related to toxicants and immunological parameters. The resulting117 clinical trials were examined for immune-related outcomes and specific biomarkers evaluated in subjects exposed to occupational and environmental toxicants. After categorization, relevant immunological outcomes and biomarkers were identified related to systemic and airway inflammation, modulation of immune cells, allergy and autoimmunity. In general, the immune markers related to inflammation are more frequently investigated for exposure to pollutants, namely IL-6, C-reactive protein (CRP) and nitric oxide (NO). Nevertheless, the data also indicated that prospective biomarkers of effect are gaining ground and a guiding representation of the established and novel biomarkers is suggested for upcoming trials. Finally, potential protective strategies to mitigate the adverse effects of specific toxicants are underlined for future studies.

Inflammatory markers in exhaled breath condensate in bronchial asthma

Chronic respiratory diseases are among the most common non- infection diseases. In particular, it is bronchial asthma (BA), characterized by bronchial hyperreactivity and varying degrees of airway obstruction that is the cause of morbidity and mortality. The methods available for the information about the presence of inflammation in the airways, such as bronchoscopy and bronchial biopsy to be obtained have currently been invasive and difficult in everyday clinical practice, especially for children and seriously ill patients. In this regard, recently there has been an increase in the development of non-invasive methods for diagnosing the respiratory system, being comfortable and painless for trial subjects, especially children, also providing the inflammatory process control in the lungs, the severity assessment and monitoring the treatment process. The exhaled breath condensate (EBC) is of great attention, which is a source of various biomolecules, including nitric oxide (NO), leukotrienes, 8-isoprostane, prostaglandins, etc., being locally or systemically associated with disease processes in the body. Of particular interest is the presence of cytokines in EBC, namely the specific proteins produced by various cells of the body that play a key role in inflammatory processes in AD and provide cell communication (cytokine network). Thereby, it becomes possible for the severity and control level of childhood bronchial asthma using only the EBC analysis to be assessed. In addition, the non-invasiveness of this method allows it to be reused for monitoring lung diseases of even the smallest patients, including infants. Thus, the field of metabolite analysis in EBC has been developing and, in the near future, the given method is likely to be the most common for diagnosing the respiratory system diseases in both children and adults.

Mass spectrometry based proteome profiling of the exhaled breath condensate for lung cancer biomarkers search

INTRODUCTION

Lung cancer remains the most prevalent cause of cancer mortality worldwide mainly due to insufficient availability of early screening methods for wide-scale application. Exhaled breath condensate (EBC) is currently considered as one of the promising targets for early screening and is particularly attractive due to its absolutely noninvasive collection and possibility for long-term frozen storage. EBC proteome analysis can provide valuable information about the (patho)physiological changes in the respiratory system and may help to identify in time a high risk of lung cancer. Mass spectrometry (MS) profiling of EBC proteome seems to have no alternative in obtaining the most extensive data and characteristic marker panels for screening.

AREAS COVERED

This special report summarizes the data of several proteomic studies of EBC in normal and lung cancer (from 2012 to 2021, PubMed), focuses on the possible reasons for the significant discrepancy in the results, and discusses some aspects for special attention in further studies.

EXPERT OPINION

The significant discrepancy in the results of various studies primarily highlights the need to create standardized protocols for the collection and preparation of EBC for proteomic analysis. The application of quantitative and targeted LC-MS/MS based approaches seems to be the most promising in further EBC proteomic studies.

Functional significance of 8-isoprostanes in sinonasal disease and asthma

BACKGROUND

The purpose of this study was to investigate how 8-isoprostanes, used as a marker of airway oxidative stress, were related to sinus disease and asthma.

METHODS

We analyzed samples and data from two separate studies, one investigating sinonasal disease in asthma, the other investigating the effect of BMI on airway disease. We measured airway (nasal lavage) 8-isoprostanes and investigated the relationship with measures of sinus and asthma symptoms, asthma control and lung function.

RESULTS

The study of people with sinonasal disease and poorly controlled asthma included 48 obese, 31 overweight and 23 lean participants. In multivariate analysis, nasal lavage 8-isoprostane levels increased with increasing BMI (p < 0.01), and were higher in Caucasian than African American participants (p = 0.01). Sinus symptoms were inversely related to nasal 8-isoprostanes (p = 0.02) independent of BMI and Race. In the study investigating the effect of BMI on airway disease, we enrolled 13 controls with obesity and 21 people with obesity and asthma: 8-isoprostane levels were higher in obese controls than in obese people with asthma (p < 0.01), and levels were inversely related to sinus symptoms (p = 0.02) and asthma control (p < 0.01).

INTERPRETATION

8-isoprostanes in nasal lavage are increased in obesity, and increased in Caucasians compared with African Americans. However, levels are higher in obese controls than obese people with asthma, and appear inversely related to symptoms of airway disease.

CLINICAL IMPLICATION

Airway 8-isoprostanes likely reflect complex oxidative signaling pathways, which are altered in obesity and those of different race, rather than being a simple marker of airway oxidative injury.

CAPSULE SUMMARY

Increased airway oxidative signaling (8-isoprostanes), may reflect normal physiology in the setting of obesity, as decreased levels are associated with disease activity in people with chronic sinonasal disease and asthma.

Exhaled Breath Condensate-A Non-Invasive Approach for Diagnostic Methods in Asthma

The pathophysiology of asthma has been intensively studied, but its underlying mechanisms such as airway inflammation, control of airway tone, and bronchial reactivity are still not completely explained. There is an urgent need to implement novel, non-invasive diagnostic tools that can help to investigate local airway inflammation and connect the molecular pathways with the broad spectrum of clinical manifestations of asthma. The new biomarkers of different asthma endotypes could be used to confirm diagnosis, predict asthma exacerbations, or evaluate treatment response. In this paper, we briefly describe the characteristics of exhaled breath condensate (EBC) that is considered to be an interesting source of biomarkers of lung disorders. We look at the composition of EBC, some aspects of the collection procedure, the proposed biomarkers for asthma, and its clinical implications. We also indicate the limitations of the method and potential strategies to standardize the procedure of EBC collection and analytical methods.

Chemiluminescent Measurement of Hydrogen Peroxide in the Exhaled Breath Condensate of Healthy and Asthmatic Adults

Reactive oxygen species are centrally involved in the pathophysiology of airway diseases such as asthma and chronic obstructive pulmonary disease. This study reports the development of a chemiluminescence assay and a device for measuring hydrogen peroxide in the exhaled breath condensate of asthma patients and healthy participants. A stand-alone photon detection device was constructed for use with an optimized chemiluminescence assay. Calibrations using a catalase control to scavenge residual hydrogen peroxide in calibrant solutions provided analytically sensitive and specific measurements. We evaluated exhaled breath condensate hydrogen peroxide in 60 patients (ages 20-83; 30 healthy patients and 30 asthma patients) recruited from the John Peter Smith Hospital Network. The exhaled breath condensate hydrogen peroxide concentrations trended toward higher values in asthma patients compared to healthy participants (mean 142.5 vs 115.5 nM; p = 0.32). Asthma patients who had not used an albuterol rescue inhaler in the past week were compared to those who had and showed a trend toward higher hydrogen peroxide levels (mean 172.8 vs 115.9 nM; p = 0.25), and these patients also trended toward higher hydrogen peroxide than healthy participants (mean 172.8 vs 115.5 nM; p = 0.14). This pilot study demonstrates the ability of the newly developed assay and device to measure exhaled breath condensate hydrogen peroxide in asthma patients and healthy participants. The trends observed in this study are in agreement with previous literature and warrant further investigation of using this system to measure exhaled breath condensate hydrogen peroxide for monitoring oxidative stress in asthma.

Improvement of asthma control after laser acupuncture and its impact on exhaled 8-isoprostane as an oxidative biomarker in chronic bronchial asthma

Traditional medicine may not control bronchial asthma. Many patients have uncontrolled symptoms and the underlying ongoing inflammation is persistent.

OBJECTIVE

to assess efficacy of laser acupuncture in improving asthma symptoms and underlying oxidative stress through monitoring exhaled 8-isoprostane.

METHOD

48 asthmatic (case group) received successive low level laser acupuncture sessions to stimulate acupoints for chronic asthma and 24 asthmatics received deactivated laser acupuncture sessions (control group). Asthma symptoms, asthma control questionnaire, concentration of 8-Isoprostane in exhaled breath condensate and airway resistance were assessed before and after laser acupuncture therapy.

RESULTS

After the completion of the course of laser acupuncture therapy, we observed significant improvement of asthma symptoms. Asthma control questionnaire improved from 9.7 ± 3.3 to 21.8 ± 3.6 (p 0.001). EBC 8-Isoprostane dropped from 14.7 ± 5.4 to 8.1 ± 5.0 (p 0.001). The airway resistance at R5 and R20 significantly decreased from 116.6 ± 25.8 & 124.5 ± 31.2 to 101.5 ± 25.6 &110.9 ± 29.9 respectively (p 0.001). Control patients who received sham acupuncture therapy did not show such improvement.

CONCLUSION

Laser acupuncture is an effective modality in treating bronchial asthma as evidenced by improved symptoms, airway resistance, and oxidative biomarkers.

Microfluidic Immunoaffinity Basophil Activation Test for Point-of-Care Allergy Diagnosis

BACKGROUND

The flow cytometry-based basophil activation test (BAT) is used for the diagnosis of allergic response. However, flow cytometry is time-consuming, requiring skilled personnel and cumbersome processing, which has limited its use in the clinic. Here, we introduce a novel microfluidic-based immunoaffinity BAT (miBAT) method.

METHODS

The microfluidic device, coated with anti-CD203c, was designed to capture basophils directly from whole blood. The captured basophils are activated by anti-FcεRI antibody followed by optical detection of CD63 expression (degranulation marker). The device was first characterized using a basophil cell line followed by whole blood experiments. We evaluated the device with ex vivo stimulation of basophils in whole blood from healthy controls and patients with allergies and compared it with flow cytometry.

RESULTS

The microfluidic device was capable of capturing basophils directly from whole blood followed by in vitro activation and quantification of CD63 expression. CD63 expression was significantly higher (P = 0.0002) in on-chip activated basophils compared with nonactivated cells. The difference in CD63 expression on anti-FcεRI-activated captured basophils in microfluidic chip was significantly higher (P = 0.03) in patients with allergies compared with healthy controls, and the results were comparable with flow cytometry analysis (P = 0.04). Furthermore, there was no significant difference of CD63% expression in anti-FcεRI-activated captured basophils in microfluidic chip compared with flow cytometry.

CONCLUSIONS

We report on the miBAT. This device is capable of isolating basophils directly from whole blood for on-chip activation and detection. The new miBAT method awaits validation in larger patient populations to assess performance in diagnosis and monitoring of patients with allergies at the point of care.

Measuring acute pulmonary responses to occupational wildland fire smoke exposure using exhaled breath condensate

Wildland firefighters are directly exposed to elevated levels of wildland fire (WF) smoke. Although studies demonstrate WF smoke exposure is associated with lung function changes, few studies that use invasive sample collection methods have been conducted to investigate underlying biochemical changes. These methods are also either unrepresentative of the deeper airways or capable of inducing inflammation. In the present study, levels of biomarkers of oxidative stress (8-isoprostane) and pro-inflammatory response (interleukin-6 [IL-6], interleukin-8 [IL-8], C-reactive protein [CRP], and soluble intercellular adhesion molecule-1 [sICAM-1]) were determined in exhaled breath condensate (EBC) samples that were collected from firefighters before, after, and next morning following prescribed burn and regular work shifts. Results show only a marginal cross-shift increase in 8-isoprostane on burn days (.05 < p value < .1), suggesting WF smoke exposure causes mild pulmonary responses.

Influence of viral infection on the relationships between airway cytokines and lung function in asthmatic children

BACKGROUND

Few longitudinal studies examine inflammation and lung function in asthma. We sought to determine the cytokines that reduce airflow, and the influence of respiratory viral infections on these relationships.

METHODS

Children underwent home collections of nasal lavage during scheduled surveillance periods and self-reported respiratory illnesses. We studied 53 children for one year, analyzing 392 surveillance samples and 203 samples from 85 respiratory illnesses. Generalized estimated equations were used to evaluate associations between nasal lavage biomarkers (7 mRNAs, 10 proteins), lung function and viral infection.

RESULTS

As anticipated, viral infection was associated with increased cytokines and reduced FVC and FEV1. However, we found frequent and strong interactions between biomarkers and virus on lung function. For example, in the absence of viral infection, CXCL10 mRNA, MDA5 mRNA, CXCL10, IL-4, IL-13, CCL4, CCL5, CCL20 and CCL24 were negatively associated with FVC. In contrast, during infection, the opposite relationship was frequently found, with IL-4, IL-13, CCL5, CCL20 and CCL24 levels associated with less severe reductions in both FVC and FEV1.

CONCLUSIONS

In asthmatic children, airflow obstruction is driven by specific pro-inflammatory cytokines. In the absence of viral infection, higher cytokine levels are associated with decreasing lung function. However, with infection, there is a reversal in this relationship, with cytokine abundance associated with reduced lung function decline. While nasal samples may not reflect lower airway responses, these data suggest that some aspects of the inflammatory response may be protective against viral infection. This study may have ramifications for the treatment of viral-induced asthma exacerbations.

Exhaled Breath Condensate: Pilot Study of the Method and Initial Experience in Healthy Subjects

Analysis of Exhaled breath condensate (EBC) is a re-discovered approach to monitoring the course of the disease and reduce invasive methods of patient investigation. However, the major disadvantage and shortcoming of the EBC is lack of reliable and reproducible standardization of the method. Despite many articles published on EBC, until now there is no clear consensus on whether the analysis of EBC can provide a clue to diagnosis of the diseases. The purpose of this paper is to investigate our own method, to search for possible standardization and to obtain our own initial experience. Thirty healthy volunteers provided the EBC, in which we monitored the density, pH, protein, chloride and urea concentration. Our results show that EBC pH is influenced by smoking, and urea concentrations are affected by the gender of subjects. Age of subjects does not play a role. The smallest coefficient of variation between individual volunteers is for density determination. Current limitations of EBC measurements are the low concentration of many biomarkers. Standardization needs to be specific for each individual biomarker, with focusing on optimal condensate collection. EBC analysis has a potential become diagnostic test, not only for lung diseases.

Ocimum basilicum affects tracheal responsiveness, lung inflammatory cells and oxidant-antioxidant biomarkers in sensitized rats

The anti-inflammatory and antioxidant effects of Ocimum basilicum (O. basilicum) was shown previously. In the present study, the effect of O. basilicum on tracheal responsiveness (TR) to methacholine and ovalbumin (OVA), bronchoalveolar lavage fluid (BALF) levels of oxidant-antioxidant biomarkers as well as total and differential white blood cell (WBC) in sensitized rats was examined. Six groups of rats including control (group C), sensitized rats to OVA (group S), S groups treated with three concentrations of O. basilicum (0.75, 1.50, and 3.00 mg/ml) and one concentration of dexamethasone (1.25 μg/ml) (n = 8 for all groups) were studied. TR to methacholine and OVA, total WBC count, percentages of eosinophils, monocytes, neutrophils, and levels of oxidant biomarkers were significantly increased but other measured parameters were significantly decreased in group S compared to group C. TR to methacholine and OVA, percentages of eosinophils, monocytes, neutrophils, and levels of oxidant biomarkers were significantly decreased but lymphocytes and antioxidant biomarkers were significantly increased in S groups treated with dexamethasone and at least two higher concentrations of the extract compared to group S. Total WBC count was also decreased in treated S groups with dexamethasone and high extract concentration. The effect of extract on most measured parameters was significantly lower than dexamethasone treatment. The effects of two higher concentrations of the extract on most variables were significantly higher than the effect of low extract concentration. These results showed the concentration-dependent effect of O. basilicum on tracheal responses, lung inflammatory cells, and oxidant-antioxidant parameters in sensitized rats.

Rhinovirus infection induces distinct transcriptome profiles in polarized human macrophages

Infections with rhinovirus (RV) cause asthma exacerbations. Recent studies suggest that macrophages play a role in asthmatic airway inflammation and the innate immune response to RV infection. Macrophages exhibit phenotypes based on surface markers and gene expression. We hypothesized that macrophage polarization state alters gene expression in response to RV infection. Cells were derived from human peripheral blood derived monocytes. M1 and M2 polarization was carried out by using IFN-γ and IL-4, respectively, and RNA was extracted for Affymetrix Human Gene ST2.1 exon arrays. Selected genes were validated by quantitative (q)PCR. Treatment of nonactivated (M0) macrophages with IFN-γ and IL-4 induced the expression of 252 and 153 distinct genes, respectively, including previously-identified M1 and M2 markers. RV infection of M0 macrophages induced upregulation of 232 genes; pathway analysis showed significant overrepresentation of genes involved in IFN-α/β signaling and cytokine signaling in the immune system. RV infection induced differential expression of 195 distinct genes in M1-like macrophages but only seven distinct genes in M2-like-polarized cells. In a secondary analysis, comparison between M0-, RV-infected, and M1-like-polarized, RV-infected macrophages revealed differential expression of 227 genes including those associated with asthma and its exacerbation. qPCR demonstrated increased expression of CCL8, CXCL10, TNFSF10, TNFSF18, IL6, NOD2, and GSDMD and reduced expression of VNN1, AGO1, and AGO2. Together, these data show that, in contrast to M2-like-polarized macrophages, gene expression of M1-like macrophages is highly regulated by RV.

Value of free/total prostate-specific antigen (f/t PSA) ratios for prostate cancer detection in patients with total serum prostate-specific antigen between 4 and 10 ng/mL: A meta-analysis

BACKGROUND

Prostate carcinoma is a common disease that occurs in men over 50 years old. Many studies have explored the effect of free/total prostate-specific antigen (f/t PSA) ratio in monitoring prostate cancer. We conducted a meta-analysis to identify the accuracy of the f/t PSA ratio in the diagnosis of prostate cancer in patients who have PSA levels of 4 to 10 ng/mL.

METHODS

Databases searched included PubMed and OVID databases, from inception to March 2017, after a systematical review, sensitivity, specificity, and other measures of accuracy of the f/t PSA ratio in the diagnosis of prostate cancer were pooled. We used summary receiver operating characteristic curves to summarize overall test performance.

RESULTS

Fifteen case-control studies from 14 articles were identified. The results indicated that the sensitivity of the f/t PSA ratio in the diagnosis of prostate cancer ranged from 0.5 to 0.94 (pooled sensitivity 0.70, 95% CI: 0.67-0.72), whereas its specificity ranged from 0.31 to 0.93 (pooled specificity 0.55, 95% CI: 0.57-0.60). The positive likelihood ratio was 1.85 (95% CI: 1.56-2.20), negative likelihood ratio was 0.42 (95% CI: 0.34-0.53), and diagnostic odds ratio was 4.81 (9.53% CI: 3.33-6.94).

CONCLUSIONS

The f/t PSA ratio determination has a low sensitivity and specificity for the diagnosis of prostate cancer; it would not be useful for the diagnosis of prostate cancer by itself. The results of f/t PSA ratio measurements should refer to the clinical manifestations and the results of conventional tests such as biopsies.

Biomarkers in inflammometry pediatric asthma: utility in daily clinical practice

Asthma is a common disease in both high and lower income countries that starts early and persists often for life. A correct and accurate diagnosis, treatment and follow-up during childhood are essential for a better understanding of adult asthma and avoiding over- or under-treatment. Th2 inflammation in children with asthma symptoms is usually assessed by measuring with serum total IgE, blood eosinophilia and FeNO levels that may help to predict asthma, particularly in those infants and young children in whom lung function tests are difficult to perform. FeNO measurement, compared to intra-individual levels, may be useful also for ascertaining treatment adherence. Nevertheless, an isolated measurement may be insufficient and only the combination of these markers improves the diagnosis, phenotyping and follow-up of an asthmatic child.

Biomarkers of oxidative stress and antioxidants in severe asthma: A Prospective Case-Control Study

BACKGROUND

Bronchial airway inflammation is the hallmark of asthma, which may be driven by an imbalance between oxidative stress and antioxidant defenses. Antioxidants deficiency may play a role, but this has remained unconfirmed.

OBJECTIVE

To evaluate the oxidative stress burden and antioxidants defenses in patients with increasing asthma severity.

METHODS

This prospective case-control study compared fractional exhaled nitric oxide (FeNO), exhaled breath condensate nitrite/nitrate (EBC-NOx), spirometry, and serum vitamins and trace elements among patients with and without asthma.

RESULTS

Sixty participants were recruited (30 with severe asthma number; 23 women [76.7%]; mean age, 41.4 years; mean forced expiratory volume in 1 second [FEV₁], 2.2 L [72.2% predicted]; mean inhaled corticosteroid dosage, 2,540 μg/d; 18/30 [60%] receiving maintenance oral corticosteroids; 15 with mild asthma; all corticosteroids naïve; 9 women [60%]; mean age, 34.6 years; mean FEV₁, 3.48 L [100.5% predicted]; 15 healthy controls; 12 women [80%]; mean age, 37.6 years; and mean FEV₁, 3.53 L [111.7% predicted]). The mean FeNO levels increased significantly with increasing asthma severity (P = .01), but the EBC-NOx levels did not change significantly (P = .90). Paradoxically, vitamin A and vitamin E increased with increased disease severity, with vitamin E levels increasing significantly (P = .07 and P < .001, respectively). There was no significant difference between groups in the levels of copper (P = .37), zinc (P = .97), or selenium (P = .90).

CONCLUSION

FeNO but not EBC-NOx is increased significantly with asthma severity with no evidence of vitamins or trace elements deficiency in severe asthma. Impaired oxidative stress defenses in severe asthma may be driven by factors other than vitamins or trace elements deficiency.

A European Respiratory Society technical standard: exhaled biomarkers in lung disease

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 for F_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 and F_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.

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.

Toward point-of-care management of chronic respiratory conditions: Electrochemical sensing of nitrite content in exhaled breath condensate using reduced graphene oxide

We present a portable non-invasive approach for measuring indicators of inflammation and oxidative stress in the respiratory tract by quantifying a biomarker in exhaled breath condensate (EBC). We discuss the fabrication and characterization of a miniaturized electrochemical sensor for detecting nitrite content in EBC using reduced graphene oxide. The nitrite content in EBC has been demonstrated to be a promising biomarker of inflammation in the respiratory tract, particularly in asthma. We utilized the unique properties of reduced graphene oxide (rGO); specifically, the material is resilient to corrosion while exhibiting rapid electron transfer with electrolytes, thus allowing for highly sensitive electrochemical detection with minimal fouling. Our rGO sensor was housed in an electrochemical cell fabricated from polydimethyl siloxane (PDMS), which was necessary to analyze small EBC sample volumes. The sensor is capable of detecting nitrite at a low over-potential of 0.7 V with respect to an Ag/AgCl reference electrode. We characterized the performance of the sensors using standard nitrite/buffer solutions, nitrite spiked into EBC, and clinical EBC samples. The sensor demonstrated a sensitivity of 0.21 μA μM^-1 cm^-2 in the range of 20-100 μM and of 0.1 μA μM^-1 cm^-2 in the range of 100-1000 μM nitrite concentration and exhibited a low detection limit of 830 nM in the EBC matrix. To benchmark our platform, we tested our sensors using seven pre-characterized clinical EBC samples with concentrations ranging between 0.14 and 6.5 μM. This enzyme-free and label-free method of detecting biomarkers in EBC can pave the way for the development of portable breath analyzers for diagnosing and managing changes in respiratory inflammation and disease.

Asthma phenotypes in childhood

INTRODUCTION

Asthma is no longer thought of as a single disease, but rather a collection of varying symptoms expressing different disease patterns. One of the ongoing challenges is understanding the underlying pathophysiological mechanisms that may be responsible for the varying responses to treatment. Areas Covered: This review provides an overview of our current understanding of the asthma phenotype concept in childhood and describes key findings from both conventional and data-driven methods. Expert Commentary: With the vast amounts of data generated from cohorts, there is hope that we can elucidate distinct pathophysiological mechanisms, or endotypes. In return, this would lead to better patient stratification and disease management, thereby providing true personalised medicine.

Evaluation of the improvement effect of laser acupuncture biostimulation in asthmatic children by exhaled inflammatory biomarker level of nitric oxide

Variable therapy of asthma is not sufficient yet to achieve good asthma control. Therapy decision requires serial investigations. Low-level laser acupuncture is a suitable non-invasive modality of complementary medicine. The exhaled breath condensate (EBC) is easy and useful to evaluate the efficacy of drugs or novel therapy. This study aimed to evaluate the effectiveness of low-level laser biostimulation of acupuncture points on asthma improvement in children. Forty-eight asthmatic children were subdivided into case (laser) group, which received 12 direct contact low-power laser acupuncture sessions (three sessions/week) on specific traditional Chinese acupuncture points for bronchial asthma, and control asthmatic group, which received sham laser acupuncture on the same acupoints and number of sessions of the case (laser) group. Low-power Multichannel Aculas-AM laser (grade II) of wave length 780 nm, output power 800 mw, and beam spot size 0.1 cm² with continuous mode was used. Eighteen acupoints were stimulated for 2 min, giving energy of 9.6 J/cm²/acupoint. The total session time was 3 min. Both groups were evaluated pre- and post-laser acupuncture intervention by recording levels of asthma control, pulmonary function, and EBC nitric oxide. In the case (laser) group, 91.7 % of patients experienced an improvement in the level of asthma control versus 25 % in the control group (p < 0.001). This was associated with a significant decrease of the breath condensate FENO concentration (p < 0.001) and significant increase of spirometry parameters (p < 0.001) in the case (laser) group. Application of laser acupuncture treatment given with conventional therapy can effectively improve bronchial asthma more than prescription of medications alone could.

Particulate Oxidative Burden as a Predictor of Exhaled Nitric Oxide in Children with Asthma

BACKGROUND

Epidemiological studies have provided strong evidence that fine particulate matter (PM2.5; aerodynamic diameter ≤ 2.5 μm) can exacerbate asthmatic symptoms in children. Pro-oxidant components of PM2.5 are capable of directly generating reactive oxygen species. Oxidative burden is used to describe the capacity of PM2.5 to generate reactive oxygen species in the lung.

OBJECTIVE

In this study we investigated the association between airway inflammation in asthmatic children and oxidative burden of PM2.5 personal exposure.

METHODS

Daily PM2.5 personal exposure samples (n = 249) of 62 asthmatic school-aged children in Montreal were collected over 10 consecutive days. The oxidative burden of PM2.5 samples was determined in vitro as the depletion of low-molecular-weight antioxidants (ascorbate and glutathione) from a synthetic model of the fluid lining the respiratory tract. Airway inflammation was measured daily as fractional exhaled nitric oxide (FeNO).

RESULTS

A positive association was identified between FeNO and glutathione-related oxidative burden exposure in the previous 24 hr (6.0% increase per interquartile range change in glutathione). Glutathione-related oxidative burden was further found to be positively associated with FeNO over 1-day lag and 2-day lag periods. Results further demonstrate that corticosteroid use may reduce the FeNO response to elevated glutathione-related oxidative burden exposure (no use, 15.8%; irregular use, 3.8%), whereas mold (22.1%), dust (10.6%), or fur (13.1%) allergies may increase FeNO in children with versus children without these allergies (11.5%). No association was found between PM2.5 mass or ascorbate-related oxidative burden and FeNO levels.

CONCLUSIONS

Exposure to PM2.5 with elevated glutathione-related oxidative burden was associated with increased FeNO.

CITATION

Maikawa CL, Weichenthal S, Wheeler AJ, Dobbin NA, Smargiassi A, Evans G, Liu L, Goldberg MS, Godri Pollitt KJ. 2016. Particulate oxidative burden as a predictor of exhaled nitric oxide in children with asthma. Environ Health Perspect 124:1616-1622; http://dx.doi.org/10.1289/EHP175.

Trace metal exposure is associated with increased exhaled nitric oxide in asthmatic children

BACKGROUND

Children with asthma experience increased susceptibility to airborne pollutants. Exposure to traffic and industrial activity have been positively associated with exacerbation of symptoms as well as emergency room visits and hospitalisations. The effect of trace metals contained in fine particulate matter (aerodynamic diameter 2.5 μm and lower, PM2.5) on acute health effects amongst asthmatic children has not been well investigated. The objective of this panel study in asthmatic children was to determine the association between personal daily exposure to ambient trace metals and airway inflammation, as measured by fractional exhaled nitric oxide (FeNO).

METHODS

Daily concentrations of trace metals contained on PM2.5 were determined from personal samples (n = 217) collected from 70 asthmatic school aged children in Montreal, Canada, over ten consecutive days. FeNO was measured daily using standard techniques.

RESULTS

A positive association was found between FeNO and children's exposure to an indicator of vehicular non-tailpipe emissions (8.9 % increase for an increase in the interquartile range (IQR) in barium, 95 % confidence interval (CI): 2.8, 15.4) as well as exposure to an indicator of industrial emissions (7.6 % increase per IQR increase in vanadium, 95 % CI: 0.1, 15.8). Elevated FeNO was also suggested for other metals on the day after the exposure: 10.3 % increase per IQR increase in aluminium (95 % CI: 4.2, 16.6) and 7.5 % increase per IQR increase in iron (95 % CI: 1.5, 13.9) at a 1-day lag period.

CONCLUSIONS

Exposures to ambient PM2.5 containing trace metals that are markers of traffic and industrial-derived emissions were associated in asthmatic children with an enhanced FeNO response.

Exhaled breath condensate for lung cancer protein analysis: a review of methods and biomarkers

Lung cancer is a leading cause of cancer-related deaths worldwide, and is considered one of the most aggressive human cancers, with a 5 year overall survival of 10-15%. Early diagnosis of lung cancer is ideal; however, it is still uncertain as to what technique will prove successful in the systematic screening of high-risk populations, with the strongest evidence currently supporting low dose computed tomography (LDCT). Analysis of exhaled breath condensate (EBC) has recently been proposed as an alternative low risk and non-invasive screening method to investigate early-stage neoplastic processes in the airways. However, there still remains a relative paucity of lung cancer research involving EBC, particularly in the measurement of lung proteins that are centrally linked to pathogenesis. Considering the ease and safety associated with EBC collection, and advances in the area of mass spectrometry based profiling, this technology has potential for use in screening for the early diagnosis of lung cancer. This review will examine proteomics as a method of detecting markers of neoplasia in patient EBC with a particular emphasis on LC, as well as discussing methodological challenges involving in proteomic analysis of EBC specimens.

Relationships between adult asthma and oxidative stress markers and pH in exhaled breath condensate: a systematic review

Oxidative stress has a recognized role in the pathophysiology of asthma. Recently, interest has increased in the assessment of pH and airway oxidative stress markers. Collection of exhaled breath condensate (EBC) and quantification of biomarkers in breath samples can potentially indicate lung disease activity and help in the study of airway inflammation, and asthma severity. Levels of oxidative stress markers in the EBC have been systematically evaluated in children with asthma; however, there is no such systematic review conducted for adult asthma. A systematic review of oxidative stress markers measured in EBC of adult asthma was conducted, and studies were identified by searching MEDLINE and SCOPUS databases. Sixteen papers met the inclusion criteria. Concentrations of exhaled hydrogen ions, nitric oxide products, hydrogen peroxide and 8-isoprostanes were generally elevated and related to lower lung function tests in adults with asthma compared to healthy subjects. Assessment of EBC markers may be a noninvasive approach to evaluate airway inflammation, exacerbations, and disease severity of asthma, and to monitor the effectiveness of anti-inflammatory treatment regimens. Longitudinal studies, using standardized analytical techniques for EBC collection, are required to establish reference values for the interpretation of EBC markers in the context of asthma.

A chemiluminescent platform for smartphone monitoring of H2O2 in human exhaled breath condensates

Noninvasive measurement of oxidative markers in clinical samples has the potential to rapidly provide information for disease management, but is limited by the need for expensive analytical instrumentation that precludes home monitoring or point-of-care applications. We have developed a simple to use diagnostic platform for airway hydrogen peroxide (H₂O₂) that combines optimized reaction-based chemiluminescent designs with an inexpensive home-built darkbox and readily available smartphone cameras. Specialized photography software applications and analysis of pixel intensity enables quantification of sample concentrations. Using this platform, sample H₂O₂ concentrations as low as 264nM can be detected. The platform has been used to measure H₂O₂ in the exhaled breath condensates of human subjects, showing good agreement with the standard Amplex Red assay.

The analysis of volatile organic compounds in exhaled breath and biomarkers in exhaled breath condensate in children - clinical tools or scientific toys?

Current monitoring strategies for respiratory diseases are mainly based on clinical features, lung function and imaging. As airway inflammation is the hallmark of many respiratory diseases in childhood, noninvasive methods to assess the presence and severity of airway inflammation might be helpful in both diagnosing and monitoring paediatric respiratory diseases. At present, the measurement of fractional exhaled nitric oxide is the only noninvasive method available to assess eosinophilic airway inflammation in clinical practice. We aimed to evaluate whether the analysis of volatile organic compounds (VOCs) in exhaled breath (EB) and biomarkers in exhaled breath condensate (EBC) is helpful in diagnosing and monitoring respiratory diseases in children. An extensive literature search was conducted in Medline, Embase and PubMed on the analysis and applications of VOCs in EB and EBC in children. We retrieved 1165 papers, of which nine contained original data on VOCs in EB and 84 on biomarkers in EBC. These were included in this review. We give an overview of the clinical applications in childhood and summarize the methodological issues. Several VOCs in EB and biomarkers in EBC have the potential to distinguish patients from healthy controls and to monitor treatment responses. Lack of standardization of collection methods and analysis techniques hampers the introduction in clinical practice. The measurement of metabolomic profiles may have important advantages over detecting single markers. There is a lack of longitudinal studies and external validation to reveal whether EB and EBC analysis have added value in the diagnostic process and follow-up of children with respiratory diseases. In conclusion, the use of VOCs in EB and biomarkers in EBC as markers of inflammatory airway diseases in children is still a research tool and not validated for clinical use.

Monitoring asthma in childhood: lung function, bronchial responsiveness and inflammation

This review focuses on the methods available for measuring reversible airways obstruction, bronchial hyperresponsiveness (BHR) and inflammation as hallmarks of asthma, and their role in monitoring children with asthma. Persistent bronchial obstruction may occur in asymptomatic children and is considered a risk factor for severe asthma episodes and is associated with poor asthma outcome. Annual measurement of forced expiratory volume in 1 s using office based spirometry is considered useful. Other lung function measurements including the assessment of BHR may be reserved for children with possible exercise limitations, poor symptom perception and those not responding to their current treatment or with atypical asthma symptoms, and performed on a higher specialty level. To date, for most methods of measuring lung function there are no proper randomised controlled or large longitudinal studies available to establish their role in asthma management in children. Noninvasive biomarkers for monitoring inflammation in children are available, for example the measurement of exhaled nitric oxide fraction, and the assessment of induced sputum cytology or inflammatory mediators in the exhaled breath condensate. However, their role and usefulness in routine clinical practice to monitor and guide therapy remains unclear, and therefore, their use should be reserved for selected cases.

Childhood asthma biomarkers: present knowledge and future steps

Asthma represents the most common chronic respiratory disease of childhood. Its current standard diagnosis relies on patient history of symptoms and confirmed expiratory airflow limitation. Nevertheless, the spectrum of asthma in clinical presentation is broad, and both symptoms and lung function may not always reflect the underlying airway inflammation, which can be determined by different pathogenetic mechanisms. For these reasons, the identification of objective biomarkers of asthma, which may guide diagnosis, phenotyping, management and treatment is of great clinical utility and might have a role in the development of personalized therapy. The availability of non-invasive methods to study and monitor disease inflammation is of relevance especially in childhood asthma. In this sense, a promising role might be played by the measurement of exhaled biomarkers, such as exhaled nitric oxide (FE(NO)) and molecules in exhaled breath condensate (EBC). Furthermore, recent studies have shown encouraging results with the application of the novel metabolomic approach to the study of exhaled biomarkers. In this paper the existing knowledge in the field of asthma biomarkers, with a special focus on exhaled biomarkers, will be highlighted.

The effect of vitamin D on airway reactivity and inflammation in asthmatic children: A double-blind placebo-controlled trial

BACKGROUND

Cross-sectional studies have reported an association of vitamin D deficiency with increased asthma prevalence and severity, and with allergies. The effect of vitamin D as sole therapy on airway hyper-reactivity (AHR) and airway inflammation has not been reported.

AIM

To evaluate the effect of vitamin D therapy on AHR as assessed by methacholine concentration, causing a 20% reduction in FEV1 (PC20 -FEV1 ) and fractional exhaled nitric oxide (FeNO), systemic markers of allergy and inflammation, and exhaled breath condensate cytokines.

PATIENTS AND METHODS

Children aged 6-18 years with a clinical diagnosis of mild asthma currently not receiving anti-inflammatory therapy and with low vitamin D levels were included in this randomized, double-blind, placebo-controlled study assessing the effect of 6 weeks of treatment with oral vitamin D 14,000 units once weekly or placebo.

RESULTS

Of the 39 patients included, 20 received vitamin D treatment and 19 received a placebo. Vitamin D replacement resulted in a significant increase in vitamin levels, which remained unchanged in the placebo group (P < 0.0001). There was no change in IgE, eosinophil count, high sensitivity C-reactive protein, FeNO levels or PC20 -FEV1 following treatment. Similar values of exhaled breath condensate cytokines (IL4, IL5, IL10, IL17, and γ interferon) were observed in both groups.

CONCLUSIONS

In our small group of children with mild asthma, no difference could be demonstrated between the effect of vitamin D and placebo, despite significant increases in vitamin D blood levels. Larger interventional studies are needed to fully explore the possible effect of vitamin D in asthma.

[Use of inflammatory markers for monitoring paediatric asthma]

The assessment of asthma control takes into account the symptoms, quality of life, lung function, and inflammatory markers. In the last few years, there has been a large increase in the number of publications related to the study of biomarkers in the management of paediatric asthma. Despite the large variety of inflammatory markers described in research studies, only a small group has shown to be useful in monitoring the disease. Induced sputum eosinophils offer the most solid evidence in assessing asthma control. Exhaled breath condensate and urinary leucotrienes could be useful in the future if there is standardisation in their procedures and interpretation of the results. Nitric oxide, basic eosinophil cationic protein, and bronchial biopsy with bronchoalveolar lavage, only appeared to be useful in a reduced group of patients.

Exhaled Breath Condensate: Technical and Diagnostic Aspects

Purpose. The aim of this study was to evaluate the 30-year progress of research on exhaled breath condensate in a disease-based approach. Methods. We searched PubMed/Medline, ScienceDirect, and Google Scholar using the following keywords: exhaled breath condensate (EBC), biomarkers, pH, asthma, gastroesophageal reflux (GERD), smoking, COPD, lung cancer, NSCLC, mechanical ventilation, cystic fibrosis, pulmonary arterial hypertension (PAH), idiopathic pulmonary fibrosis, interstitial lung diseases, obstructive sleep apnea (OSA), and drugs. Results. We found 12600 related articles in total in Google Scholar, 1807 in ScienceDirect, and 1081 in PubMed/Medline, published from 1980 to October 2014. 228 original investigation and review articles were eligible. Conclusions. There is rapidly increasing number of innovative articles, covering all the areas of modern respiratory medicine and expanding EBC potential clinical applications to other fields of internal medicine. However, the majority of published papers represent the results of small-scale studies and thus current knowledge must be further evaluated in large cohorts. In regard to the potential clinical use of EBC-analysis, several limitations must be pointed out, including poor reproducibility of biomarkers and absence of large surveys towards determination of reference-normal values. In conclusion, contemporary EBC-analysis is an intriguing achievement, but still in early stage when it comes to its application in clinical practice.

Exhaled nitric oxide correlates with IL-2, MCP-1, PDGF-BB and TIMP-2 in exhaled breath condensate of children with refractory asthma

Introduction

There is evidence that parameters obtained from exhaled breath condensate (EBC) reflect changes in the level of the airway lining fluid. The telation between exhaled nitric oxide (NO) and EBC inflammatory markers has not been analyzed in the context of the inflammatory profile in the airways in asthmatic children.

Aim

To show the cytokine profile in EBC of children with severe/refractory asthma as well as correlations between the fractional exhaled NO (FeNO) level and cytokine concentrations.

Material and methods

The study population consisted of eight children aged 8 to 17 years with IgE-dependent, severe/refractory asthma with a duration of at least 2 years. This was an observational study, the first consecutive eight patients with asthma symptoms on the day of the study visit, when EBC samples were obtained.

Results

The inter-subject variability of study cytokines ranged from 8.6 to 54.6. Cytokines with coefficient of variation < 20% were: interferon-γ, interleukins IL-2, IL-7, IL-15, IL-16, monokine induced by interferon γ (MIG) and tumor necrosis factor α. We showed a significant positive correlation between the FeNO level and crucial mediators in asthma development and progression (IL-2, MCP-1), and potent markers of airway remodeling (PDGFBB, TIMP-2). All correlations between two different variables were controlled for the effects of age, forced expiratory volume in 1 s and number of asthma exacerbations during last 12 months.

Conclusions

The profiling of cytokine expression in EBC can be reproducibly performed in children with severe/refractory asthma. When treating asthma in children, the FeNO level should be monitored as a prevention strategy of the progression of the remodeling leading to refractory/severe asthma. Exhaled breath condensate may be a useful tool to phenotype asthma via a non-invasive approach.

Inflammatory cytokines in exhaled breath condensate in children with inflammatory bowel diseases

BACKGROUND

Although inflammatory bowel diseases (IBD) affect mainly the gastrointestinal tract, the extra-intestinal manifestations are not uncommon. Different diagnostic methods have been applied to assess pulmonary involvement in patients with IBD, but majority of these methods show significant limitations in children. The aim of our study was to evaluate the usefulness of exhaled breath condensate (EBC) measurements of pro-inflammatory cytokines in children with IBD.

MATERIAL AND METHODS

Twenty-two children with Crohn's disease (CD) (mean age 13.8 ± 3.3 years), 25 with ulcerative colitis (UC) (mean age 14.1 ± 3.3 years) and 37 healthy volunteers (mean age 13.9 ± 3.6 years) were studied. IBD activity was assessed using appropriate scoring systems. None of the patients had signs or symptoms of pulmonary disease. Exhaled breath condensate was collected and EBC concentration of interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and interleukin 8 (IL-8) was measured.

RESULTS

The concentrations of all the assessed cytokines were significantly higher in the study group as compared to controls. A negative correlation between IL-1β and CD activity index was found. There were no significant relationships between TNF-α, IL-6, or IL-8 level and CD activity index as well as between IL-1β, TNF-α, IL-6, IL-8 and UC activity index. No significant correlation between the concentration of IL-1β, TNF-α, IL-6, IL-8, and IBD duration or treatment duration was found.

CONCLUSIONS

Elevated concentration of pro-inflammatory cytokines in EBC in children with IBD may suggest the presence of asymptomatic inflammation in the lower airways.

A controlled trial of acute effects of human exposure to traffic particles on pulmonary oxidative stress and heart rate variability

Background

For many individuals, daily commuting activities on roadways account for a substantial proportion of total exposure, as well as peak-level exposures, to traffic-related air pollutants (TRAPS) including ultrafine particles, but the health impacts of these exposures are not well-understood. We sought to determine if exposure to TRAPs particles during commuting causes acute oxidative stress in the respiratory tract or changes in heart rate variability (HRV), a measure of autonomic activity.

Methods

We conducted a randomized, cross-over trial in which twenty-one young adults took two 1.5-hr rides in a passenger vehicle in morning rush-hour traffic. The subjects wore a powered-air-purifying respirator, and were blinded to high-efficiency particulate air (HEPA) filtration during one of the rides. At time points before and after the rides, we measured HRV and markers of oxidative stress in exhaled breath condensate (EBC) including nitrite, the sum of nitrite and nitrate, malondialdehyde, and 8-isoprostane. We used mixed linear models to evaluate the effect of exposure on EBC and HRV outcomes, adjusting for pre-exposure response levels. We used linear models to examine the effects of particle concentrations on EBC outcomes at post-exposure time points.

Results

Mean EBC nitrite and the sum of nitrite and nitrate were increased from baseline at immediately post-exposure comparing unfiltered to filtered rides (2.11 μM vs 1.70 μM, p = 0.02 and 19.1 μM vs 10.0 μM, p = 0.02, respectively). Mean EBC malondialdehyde (MDA) concentrations were about 10% greater following the unfiltered vs. filtered exposures, although this result was not statistically significant. We found no significant associations between exposure to traffic particles and HRV outcomes at any of the time points. At immediately post-exposure, an interquartile range increase in particle number concentration was associated with statistically significant increases in nitrite (99.4%, 95% CI 32.1% to 166.7%) and nitrite + nitrate (75.7%, 95% CI 21.5% to 130.0%).

Conclusions

Increases in markers of oxidative stress in EBC may represent early biological responses to widespread exposures to TRAPs particles that affect passengers in vehicles on heavily trafficked roadways.

The extract of Zataria multiflora affect tracheal responsiveness, serum levels of NO, nitrite, PLA2, TP and histamine in sensitized Guinea pigs

ETHNOPHARMACOLOGICAL RELEVANCE

Different therapeutic effects for Zataria multiflora have been described in Iranian traditional medicine. In addition anti-inflammatory and anti-oxidant effects of this plant were previously described. The effect of the extract of Zataria multiflora on tracheal responsiveness (TR) and inflammatory mediators of sensitized guinea pigs was examined.

MATERIALS AND METHODS

Five groups of sensitized guinea pigs to ovalbumin (OA) were given drinking water alone, drinking water containing three concentrations of the extract and dexamethasone. TR to methacholine and OA, serum levels of NO, nitrite, PLA2, TP and histamine were measured (n=6, for each groups).

RESULTS

TR to methacholine and OA, serum levels of NO, nitrite, PLA2, TP and histamine were increased in sensitized animals compared to control group (p<0.05 to p<0.001). Treatment of sensitized animals with dexamethasone and most concentration of the extract lead to significantly decrease in all measured parameters compared to sensitized group (p<0.05 to p<0.001) except TP and histamine levels in treated group with dexamethasone.

CONCLUSION

These results showed a preventive effect of the extract of Zataria multiflora on tracheal responsiveness, serum level of NO, nitrite, total protein, PLA2 and histamine in sensitized guinea pigs which was equal or even more potent than dexamethasone at used concentrations.

Relationship between exhaled leukotriene and 8-isoprostane levels and asthma severity, asthma control level, and asthma control test score

OBJECTIVE

Exhaled breath condensate (EBC) is a completely non-invasive method for the collection of airway secretions to measure intense inflammation in the airways of asthmatics. It has been shown that the childhood asthma control test (c-ACT) is a good tool for use in the evaluation of asthmatics. Whether the c-ACT score and asthma control level correlate with the airway inflammation is not well known. We aimed to evaluate the relationship between exhaled cysteinyl leukotrienes (Cys-LTs) and 8-isoprostane levels and asthma severity, asthma control level and c-ACT score in asthmatic children.

METHODS

Thirty asthmatic children were evaluated with c-ACT score and pulmonary function tests. Asthma severity and asthma control level were assessed according to GINA. EBC was collected and Cys-LTs and 8-isoprostane concentrations were determined using a specific immunoassay kit.

RESULTS

Exhaled 8-isoprostane level in patients with moderate persistent asthma [114 (55-146)pg/ml] was higher than in the mild persistent group [52 (21-91)pg/ml] (p=0.05, Mann-Whitney U [MWU]). EBC 8-isoprostane in children with 1-4 asthma exacerbations/year [52 (16-80)pg/ml] was significantly lower than in children with >4 asthma exacerbations/year [114 (57-129)pg/ml] (p<0.05, MWU). No significant relation was determined between exhaled 8-isoprostane and Cys-LTs levels and c-ACT score and asthma control level. Exhaled 8-isoprostane correlated negatively with bronchodilator response (p=0.015, r=-0.45).

CONCLUSIONS

Exhaled 8-isoprostane, as an oxidative stress specifier, was found to be increased in relation with asthma exacerbation frequency and oxidative stress increases with the severity of asthma. In contrast to asthma severity level, c-ACT score and asthma control level may not reflect airway inflammation.

Altered nitrogen balance and decreased urea excretion in male rats fed cafeteria diet are related to arginine availability

Hyperlipidic diets limit glucose oxidation and favor amino acid preservation, hampering the elimination of excess dietary nitrogen and the catabolic utilization of amino acids. We analyzed whether reduced urea excretion was a consequence of higher NO x ; (nitrite, nitrate, and other derivatives) availability caused by increased nitric oxide production in metabolic syndrome. Rats fed a cafeteria diet for 30 days had a higher intake and accumulation of amino acid nitrogen and lower urea excretion. There were no differences in plasma nitrate or nitrite. NO(x) and creatinine excretion accounted for only a small part of total nitrogen excretion. Rats fed a cafeteria diet had higher plasma levels of glutamine, serine, threonine, glycine, and ornithine when compared with controls, whereas arginine was lower. Liver carbamoyl-phosphate synthetase I activity was higher in cafeteria diet-fed rats, but arginase I was lower. The high carbamoyl-phosphate synthetase activity and ornithine levels suggest activation of the urea cycle in cafeteria diet-fed rats, but low arginine levels point to a block in the urea cycle between ornithine and arginine, thereby preventing the elimination of excess nitrogen as urea. The ultimate consequence of this paradoxical block in the urea cycle seems to be the limitation of arginine production and/or availability.

PROTEINS, PEPTIDES AND AMINO ACIDS AS MARKERS OF BRONCHOPULMONARY DISEASES

The article is a review of current literature on a content of proteins, peptides and amino acids in human exhaled breath. The results of proteomics and metabolomics applying for selective detection of individual proteins, peptides and amino acids are described. The study of exhaled breath condensate and exhaled endogenous particles contained lung proteins are considered. The peculiarities of protein, peptide and amino acid content in exhaled breath at various respiratory diseases are described. It is shown that the detectable substances may be specific markers of individual diseases.

Airway oxidative stress in chronic cough

BACKGROUND

The mechanisms of chronic cough are unclear. Many reactive oxygen species affect airway sensory C-fibres which are capable to induce cough. Several chronic lung diseases are characterised by cough and oxidative stress. In asthma, an association between the cough severity and airway oxidative stress has been demonstrated. The present study was conducted to investigate whether airway oxidative stress is associated with chronic cough in subjects without chronic lung diseases.

METHODS

Exhaled breath condensate samples were obtained in 43 non-smoking patients with chronic cough and 15 healthy subjects. Exclusion criteria included a doctor's diagnosis of any lung disorders and any abnormality in lung x-ray. The concentration of 8-isoprostane was measured. In addition, the patients filled in Leicester Cough Questionnaire and underwent hypertonic saline cough provocation test, spirometry, ambulatory peak flow monitoring, nitric oxide measurement, and histamine airway challenge. In a subgroup of patients the measurements were repeated during 12 weeks' treatment with inhaled budesonide, 800 ug/day.

RESULTS

The 8-isoprostane concentrations were higher in the cough patients than in the healthy subjects (24.6 ± 1.2 pg/ml vs. 10.1 ± 1.7 pg/ml, p = 0.045). The 8-isoprostane concentration was associated with the Leicester Cough Questionnaire total score (p = 0.044) but not with the cough sensitivity to saline or other tests. Budesonide treatment did not affect the 8-isoprostane concentrations.

CONCLUSIONS

Chronic cough seems to be associated with airway oxidative stress in subjects with chronic cough but without chronic lung diseases. This finding may help to develop novel antitussive drugs.

TRIAL REGISTRATION

The study was registered in ClinicalTrials.gov database (KUH5801112), identifier NCT00859274.