Exhaled nitric oxide and exhaled breath condensate pH in severe refractory asthma

Recent insights in the role of biomarkers in severe asthma management

Contemporary asthma management requires a proactive and individualized approach, combining precision diagnosis and personalized treatment. The introduction of biologic therapies for severe asthma to everyday clinical practice, increases the need for specific patient selection, prediction of outcomes and monitoring of these costly and long-lasting therapies. Several biomarkers have been used in asthma in disease identification, prediction of asthma severity and prognosis, and response to treatment. Novel advances in the area of personalized medicine regarding disease phenotyping and endotyping, encompass the development and application of reliable biomarkers, accurately quantified using robust and reproducible methods. The availability of powerful omics technologies, together with integrated and network-based genome data analysis, and microbiota changes quantified in serum, body fluids and exhaled air, will lead to a better classification of distinct phenotypes or endotypes. Herein, in this review we discuss on currently used and novel biomarkers for the diagnosis and treatment of asthma.

Nitric oxide sensors using nanospiral ZnO thin film deposited by GLAD for application to exhaled human breath

ZnO is a promising gas sensing material for its excellent gas sensing response characteristics and long-term stability. Moreover, the improvement in the sensitivity and response speed of ZnO gas sensors can be achieved by the nanostructure fabrication. This paper proposes a facile method to deposit ZnO nanospirals using glancing angle deposition (GLAD) for application in nitric oxide (NO) sensors. ZnO nanospirals with porous characteristics have larger relative surface area and more active surfaces, compared with dense ZnO thin film. A sensor using nanospiral ZnO film shows a response factor of 16.9 to 100 ppb NO at 150 °C in 40% RH, which is 3 times larger than that of the sensor using dense ZnO film. Such a ZnO nanospiral sensor system can detect NO as low as 10 ppb which is below the NO concentration (>30 ppb) in exhaled breath of patients with asthma. The effects of working temperature and humidity on the sensor performance were investigated systematically in this work. Moreover, the sensor response showed a good selectivity to NO and high stability as the time increased up to 24 days. NO gas sensing mechanism was discussed in detail and nanospiral ZnO film sensors are promisingly applicable for exhaled human breath application compared with some other NO sensors.

Severe Eosinophilic Asthma

Asthma is a heterogeneous disease with varying severity. Severe asthma is a subject of constant research because it greatly affects patients’ quality of life, and patients with severe asthma experience symptoms, exacerbations, and medication side effects. Eosinophils, although at first considered insignificant, were later specifically associated with features of the ongoing inflammatory process in asthma, particularly in the severe case. In this review, we discuss new insights into the pathogenesis of severe asthma related to eosinophilic inflammation and the pivotal role of cytokines in a spectrum that is usually referred to as “T2-high inflammation” that accounts for almost half of patients with severe asthma. Recent literature is summarized as to the role of eosinophils in asthmatic inflammation, airway remodeling, and airway hypersensitivity. Major advances in the management of severe asthma occurred the past few years due to the new targeted biological therapies. Novel biologics that are already widely used in severe eosinophilic asthma are discussed, focusing on the choice of the right treatment for the right patient. These monoclonal antibodies primarily led to a significant reduction of asthma exacerbations, as well as improvement of lung function and patient quality of life.

Serum levels of IL-5, IL-6, IL-8, IL-13 and IL-17A in pre-defined groups of adult patients with moderate and severe bronchial asthma

BACKGROUND

Bronchial asthma (BA) is a complex disease characterised by persistent inflammation. Exhaled nitric oxide (FeNO) and blood eosinophil count (b-Eos) are biomarkers for type 2 endotype of BA.

OBJECTIVE

To analyse a panel of serum interleukins and total IgE in predefined by FeNO and b-Eos groups of moderate and severe BA patients.

METHODS

Serum levels of IL-5, IL-6, IL-8, IL-13 and IL-17A (ELISA) were measured in 30 healthy controls (HC) and 80 adult BA patients. BA patients were split into 4 groups. Group 1:Low FeNO/Low b-Eos (n = 23; 28.8%); Group 2:Low FeNO/High b-Eos (n = 17; 21.3%); Group 3:High FeNO/Low b-Eos (n = 15; 18.8%); Group 4:High FeNO/High b-Eos (n = 25; 31.3%).

RESULTS

All interleukins and total IgE were significantly higher in patients with BA as compared with HC. IL-5 levels were highest in Group 2 (p < 0.05). IL-6, IL-13 and IL-17A levels were elevated in Groups 2, 3 and 4 as compared with HC (p < 0.05). Higher IL-8 levels were associated with a pattern of current smokers. Highest IL-17A levels were found in type 2 high groups with frequent exacerbations, mostly uncontrolled and severe BA. We have found a distinct pattern for each group based on demographic, clinical, functional, immunological and inflammatory characteristics.

CONCLUSION

FeNO and b-Eos are useful in the identification of severe type 2 BA subgroups with frequent exacerbations. IL-5, IL-6, IL-13 and IL-17A are involved in the persistent type 2 immune response in moderate and severe BA. We have identified a pattern of refractory, severe type 2/IL-17A high BA in the real clinical practice.

Mapping targetable inflammation and outcomes with cystic fibrosis biomarkers

Cystic fibrosis is characterized by an overly exuberant neutrophilic inflammatory response to pathogens and other stimuli that starts very early in disease. The overwhelming nature of this response is a primary cause of remodeling and destruction of the airways, suggesting that anti-inflammatory therapies could be beneficial in CF. However, finding therapies that can effectively reduce the inflammatory response without compromising host defenses remains elusive. New approaches towards mapping inflammatory targets promise to aid in developing novel therapeutic strategies and improve outcomes in individuals with CF.

Design of Highly Selective Gas Sensors via Physicochemical Modification of Oxide Nanowires: Overview

Strategies for the enhancement of gas sensing properties, and specifically the improvement of gas selectivity of metal oxide semiconductor nanowire (NW) networks grown by chemical vapor deposition and thermal evaporation, are reviewed. Highly crystalline NWs grown by vapor-phase routes have various advantages, and thus have been applied in the field of gas sensors over the years. In particular, n-type NWs such as SnO₂, ZnO, and In₂O₃ are widely studied because of their simple synthetic preparation and high gas response. However, due to their usually high responses to C₂H₅OH and NO₂, the selective detection of other harmful and toxic gases using oxide NWs remains a challenging issue. Various strategies—such as doping/loading of noble metals, decorating/doping of catalytic metal oxides, and the formation of core–shell structures—have been explored to enhance gas selectivity and sensitivity, and are discussed herein. Additional methods such as the transformation of n-type into p-type NWs and the formation of catalyst-doped hierarchical structures by branch growth have also proven to be promising for the enhancement of gas selectivity. Accordingly, the physicochemical modification of oxide NWs via various methods provides new strategies to achieve the selective detection of a specific gas, and after further investigations, this approach could pave a new way in the field of NW-based semiconductor-type gas sensors.

Biomarkers Guided Treatment Strategies in Adult Patients with Asthma: Ready for the Clinical Field?

Asthma is a chronic inflammatory airways disorder mainly characterized by heterogeneity. In the more severe forms, a discordance often exists between symptoms and inflammation. Difficulty in managing asthma derives partly from the multiple phenotypes existing and our inability to recognize them. The use of non-invasive, with main representative the fraction of exhaled nitric oxide, or semi-invasive techniques such as induced sputum are effective tools that can help us to guide asthma treatment. In the latest years, several serum biomarkers related to asthmatic inflammation have been used for the better recognition of asthma sub-phenotypes to achieve optimization of therapy and disease outcome. In patients with mild-moderate asthma, as well as patients with more severe asthma, the use of blood eosinophils revealed an acceptable accuracy for the prediction of airway eosinophilia indicating that in future studies may facilitate both individualized treatment and management of asthma. None of the above techniques have been incorporated in clinical practice although sputum eosinophils can be used in patients with severe asthma particularly in specialized centers with great experience. Of great interest are blood eosinophils since current data support their role either as tool for treatment selections or/and as a biomarker of airway eosinophilia.

Exhaled nitric oxide monitoring does not reduce exacerbation frequency or inhaled corticosteroid dose in paediatric asthma: a randomised controlled trial

INTRODUCTION

Inhaled corticosteroid therapy (ICS) for asthma is currently modified according to symptoms and lung function. Fractional exhaled nitric oxide (FENO) has been demonstrated to be a non-invasive marker of eosinophilic inflammation. Studies of FENO-driven asthma management show variable success. Objectives: This study aimed to evaluate whether monitoring FENO can improve outpatient management of children with moderate to severe asthma using a pragmatic design.

METHODS

Children aged 6–17 years with moderate to severe asthma were recruited. Their asthma was stabilised before randomisation to FENO-driven therapy or to a standard management group where therapy was driven by conventional markers of asthma control. ICS or long-acting bronchodilator therapies were altered according to FENO levels in combination with reported symptoms in the FENO group. Participants were assessed 2 monthly for 12 months. ICS dose and exacerbation frequency change were compared between groups in an intention to treat analysis.

RESULTS

Ninety children were randomised. No difference was found between the two groups in either change in corticosteroid dose or exacerbation frequency. Results were similar in a planned secondary analysis of atopic asthmatics.

CONCLUSION

FENO-guided ICS titration does not appear to reduce corticosteroid usage or exacerbation frequency in paediatric outpatients with moderate to severe asthma. This may reflect limitations in FENO-driven management algorithms, as there are now concerns that FENO levels relate to atopy as much as they relate to asthma control.

The effectiveness of sputum pH analysis in the prediction of response to therapy in patients with pulmonary tuberculosis

Purpose. The predictive factor of response to antituberculous therapy has not been fully elucidated. Airway acidity has been thought to be a potential indicator of the bactericidal activity. Therefore, we hypothesized that monitoring airway acidity by measuring sputum pH could predict response to therapy. Methods. A total of 47 patients having newly diagnosed, smear-positive, active pulmonary tuberculosis were enrolled between October 2011 and March 2014. Sputum samples were serially analyzed before and after treatment. Eligible patients who initiated a standard 6-month treatment were monitored for the length of time to sputum smear and culture conversion. Results. There were 39 patients who completed a 2-month intensive phase of isoniazid, rifampicin, pyrazinamide, and ethambutol therapy followed by a 4-month continuation phase of isoniazid and rifampicin. Although factors including age, cavitation, sputum grade, and use of an acid-suppressant were associated with initial low sputum pH in univariate analysis, multivariate analysis revealed that only age ≥61 years was a statistically important factor predicting low pH value (p = 0.005). Further outcome analysis showed that initial low sputum pH before treatment was the only factor significantly associated with shorter length of time to both sputum smear and culture conversion (p = 0.034 and 0.019, respectively) independent of the effects of age, sputum bacterial load, extent of lung lesion, and cavitation. Thus, initial low sputum pH indicated favorable response to anti-tuberculosis therapy. Conclusions. Measuring sputum pH is an easy and inexpensive way of predicting response to standard combination therapy in patients with pulmonary tuberculosis.

Styrene-associated health outcomes at a windblade manufacturing plant

BACKGROUND

Health risks of using styrene to manufacture windblades for the green energy sector are unknown.

METHODS

Using data collected from 355 (73%) current windblade workers and regression analysis, we investigated associations between health outcomes and styrene exposure estimates derived from urinary styrene metabolites.

RESULTS

The median current styrene exposure was 53.6 mg/g creatinine (interquartile range: 19.5-94.4). Color blindness in men and women (standardized morbidity ratios 2.3 and 16.6, respectively) was not associated with exposure estimates, but was the type previously reported with styrene. Visual contrast sensitivity decreased and chest tightness increased (odds ratio 2.9) with increasing current exposure. Decreases in spirometric parameters and FeNO, and increases in the odds of wheeze and asthma-like symptoms (odds ratios 1.3 and 1.2, respectively) occurred with increasing cumulative exposure.

CONCLUSIONS

Despite styrene exposures below the recommended 400 mg/g creatinine, visual and respiratory effects indicate the need for additional preventative measures in this industry.

Biomarkers and severe asthma: a critical appraisal

Severe asthma (SA) is a clinically and etiologically heterogeneous respiratory disease which affects among 5–10 % of asthmatic patients. Despite high-dose therapy, a large patients percentage is not fully controlled and has a poor quality of life. In this review, we describe the biomarkers actually known in scientific literature and used in clinical practice for SA assessment and management: neutrophils, eosinophils, periostin, fractional exhaled nitric oxide, exhaled breath condensate and galectins. Moreover, we give an overview on clinical and biological features characterizing severe asthma, paying special attention to the potential use of these ones as reliable markers. We finally underline the need to define different biomarkers panels to select patients affected by severe asthma for specific and personalized therapeutic approach.

Biomarkers to identify sputum eosinophilia in different adult asthma phenotypes

Several biomarkers have been used to assess sputum eosinophilia in asthma. It has been suggested that the diagnostic accuracy of these biomarkers might differ between asthma phenotypes. We investigated the accuracy of biomarkers in detecting sputum eosinophilia (≥3%) in different adult asthma phenotypes.Levels of eosinophils in blood and sputum, exhaled nitric oxide fraction (FeNO) and total immunoglobulin (Ig)E from 336 adult patients, enrolled in three prospective observational clinical trials and recruited at five pulmonology outpatient departments, were analysed. Areas under the receiver operating characteristics curves (AUC) for detecting sputum eosinophilia were calculated and compared between severe and mild, obese and nonobese, atopic and nonatopic and (ex-)smoking and never-smoking asthma patients.Sputum eosinophilia was present in 116 patients (35%). In the total group the AUC was 0.83 (95% CI 0.78-0.87) for blood eosinophils, 0.82 (0.77-0.87) for FeNO and 0.69 (0.63-0.75) for total IgE. AUCs were similar for blood eosinophils and FeNO between different phenotypes. Total IgE was less accurate in detecting sputum eosinophilia in atopic and obese patients than in nonatopic and nonobese patients.Blood eosinophils and FeNO had comparable diagnostic accuracy (superior to total IgE) in identifying sputum eosinophilia in adult asthma patients, irrespective of asthma phenotype such as severe, nonatopic, obese and smoking-related asthma.

Diagnostic accuracy of minimally invasive markers for detection of airway eosinophilia in asthma: a systematic review and meta-analysis

BACKGROUND

Eosinophilic airway inflammation is associated with increased corticosteroid responsiveness in asthma, but direct airway sampling methods are invasive or laborious. Minimally invasive markers for airway eosinophilia could present an alternative method, but estimates of their accuracy vary.

METHODS

We did a systematic review and searched Medline, Embase, and PubMed for studies assessing the diagnostic accuracy of markers against a reference standard of induced sputum, bronchoalveolar lavage, or endobronchial biopsy in patients with asthma or suspected asthma (for inception to Aug 1, 2014). Unpublished results were obtained by contacting authors of studies that did not report on diagnostic accuracy, but had data from which estimates could be calculated. We assessed risk of bias with QUADAS-2. We used meta-analysis to produce summary estimates of accuracy.

FINDINGS

We included 32 studies: 24 in adults and eight in children. Of these, 26 (81%) showed risk of bias in at least one domain. In adults, three markers had extensively been investigated: fraction of exhaled nitric oxide (FeNO) (17 studies; 3216 patients; summary area under the receiver operator curve [AUC] 0·75 [95% CI 0·72-0·78]); blood eosinophils (14 studies; 2405 patients; 0·78 [0·74-0·82]); total IgE (seven studies; 942 patients; 0·65 [0·61-0·69]). In children, only FeNO (six studies; 349 patients; summary AUC 0·81 [0·72-0·89]) and blood eosinophils (three studies; 192 patients; 0·78 [0·71-0·85]) had been investigated in more than one study. Induced sputum was most frequently used as the reference standard. Summary estimates of sensitivity and specificity in detecting sputum eosinophils of 3% or more in adults were: 0·66 (0·57-0·75) and 0·76 (0·65-0·85) for FeNO; 0·71 (0·65-0·76) and 0·77 (0·70-0·83) for blood eosinophils; and 0·64 (0·42-0·81) and 0·71 (0·42-0·89) for IgE.

INTERPRETATION

FeNO, blood eosinophils, and IgE have moderate diagnostic accuracy. Their use as a single surrogate marker for airway eosinophilia in patients with asthma will lead to a substantial number of false positives or false negatives.

FUNDING

None.

Facile synthesis of hierarchical porous WO3 nanofibers having 1D nanoneedles and their functionalization with non-oxidized graphene flakes for selective detection of acetone molecules

Hierarchical and porous one-dimensional (1D) nonwoven WO₃ nanofibers were synthesized by electrospinning and controlled two-step heat-treatment, and are applicable for diabetes diagnostic sensors by selective detection of breath acetone.

Catalyst-loaded porous WO3 nanofibers using catalyst-decorated polystyrene colloid templates for detection of biomarker molecules

A new facile catalyst loading method assisted by layer-by-layer self-assembly as well as pore formation on electrospun nanofibers (NFs) can generate in-depth research for establishing high performance gas sensing composites by exploring diverse catalyst-loaded porous NF composites.

Adult asthma biomarkers

PURPOSE OF REVIEW

A variety of novel asthma treatments have been developed based on phenotypes, and the clinical trial results show promising responses. This review summarizes the current knowledge of biomarkers for the determination of asthma phenotypes.

RECENT FINDINGS

Eosinophilic inflammation is the most focused phenotype because most novel asthma treatments have targeted T-helper type 2 (Th2) pathway. Fractional-exhaled nitric oxide (FeNO) is a new method that represents an eosinophilic airway inflammation with a significant correlation with sputum eosinophilia and asthma severity instead of sputum eosinophil count that easily influenced by corticosteroid therapy. However, some reports indicated the discordance between treatment response or adjustment and FeNO levels. Serum periostin is a strong serum biomarker for eosinophilic airway inflammation and an indicator of Th2-targeted therapy (such as lebrikizumab or omalizumab) and airflow limitation. YKL-40 is associated with asthma severity and airway remodeling. In addition, genetic and metabolomic approaches have been made to determine asthma phenotypes and severity.

SUMMARY

Biomarkers such as FeNO and serum periostin represent eosinophilic airway inflammation, together with eosinophil-derived neurotoxin and osteopontin (OPN) needed more replication studies. Periostin, YKL-40, OPN and some metabolites (choline, arginine, acetone and protectin D1) are related to asthma severity and airflow limitation.

The Value of Induced Sputum in the Diagnosis and Management of Children with Bronchial Asthma

Background

Induced sputum in children with bronchial asthma represents a non-invasive method of bronchial inflammation assessment. The main objective of our study was to analyze the cellularity of sputum in patients with bronchial asthma according to the level of disease control and the controlling therapy (with/without inhaled glucocorticoids). The second objective was to establish the correlation between sputum cellularity and other indirect parameters used to evidence bronchial inflammation (exhaled nitric oxide) and obstruction (forced expiratory volume in 1 second).

Methods

The study included children with bronchial asthma that were assessed clinically (physical exam, questionnaire on the control of bronchial asthma in children) and by medical tests (induced sputum, exhaled nitric oxide, spirometry).

Results

In patients with partially controlled asthma and those with uncontrolled asthma, the eosinophils percentage in the sputum was higher than in patients with controlled asthma (19.8±26.4% respectively 9.2±20.5% versus 4.5±14.6%, p<0.001). Higher percentage of neutrophils in the sputum was found in the partially controlled and uncontrolled asthma than in the controlled asthma (43.9±20.1% respectively 51.6±38.3% versus 35±19.7%, p=0.009). We also evidenced a direct and statistically significant correlation between the exhaled nitric oxide and the neutrophils percentage in the sputum (r=0.67, p=0.0003). Also, an indirect, moderate to good correlation (r=−0.56, p=0.005) was evidenced between the values of the forced expiratory volume in 1 second and the high eosinophils percentage in the sputum.

Conclusions

In partially controlled and uncontrolled bronchial asthma the eosinophils and neutrophils count in the sputum is significantly higher than in patients with controlled asthma. There is an indirect correlation between the high eosinophils count in the sputum and the forced expiratory volume in 1 second, as well as a direct correlation between the neutrophils count and the exhaled nitric oxide, suggesting that induced sputum should be used in combination with other indirect parameters for the evidence of bronchial inflammation.

Fast responding exhaled-breath sensors using WO3 hemitubes functionalized by graphene-based electronic sensitizers for diagnosis of diseases

Diagnostic sensing device using exhaled breath of human have critical advantages due to the noninvasive diagnosis and high potential for portable device with simple analysis process. Here, we report ultrafast as well as highly sensitive bumpy WO3 hemitube nanostructure assisted by O2 plasma surface modification with functionalization of graphene-based material for the detection of acetone (CH3COCH3) and hydrogen sulfide (H2S) which are biomarkers for the diagnosis of diabetes and halitosis, respectively. 0.1 wt % graphene oxide (GO)- and 0.1 wt % thin layered graphite (GR)- WO3 hemitube composites showed response times of 11.5 ± 2.5 s and 13.5 ± 3.4 s to 1 ppm acetone as well as 12.5 ± 1.9 s and 10.0 ± 1.6 s to 1 ppm of H2S, respectively. In addition, low limits of detection (LOD) of 100 ppb (Rair/Rgas = 1.7 for acetone and Rair/Rgas = 3.3 for H2S at 300 °C) were achieved. The superior sensing properties were ascribed to the electronic sensitization of graphene based materials by modulating space charged layers at the interfaces between n-type WO3 hemitubes and p-type graphene based materials, as identified by Kelvin Probe Force Microscopy (KPFM). Rapid response and superior sensitivity of the proposed sensing materials following cyclic thermal aging demonstrates good potential for real-time exhaled breath diagnosis of diseases.

Exhaled breath condensate pH does not discriminate asymptomatic gastroesophageal reflux or the response to lansoprazole treatment in children with poorly controlled asthma

BACKGROUND

Although exhaled breath condensate (EBC) pH has been identified as an "emerging" biomarker of interest for asthma clinical trials, the clinical determinants of EBC pH remain poorly understood. Other studies have associated acid reflux-induced respiratory symptoms, for example, cough, with transient acidification of EBC.

OBJECTIVE

We sought to determine the clinical and physiologic correlates of EBC acidification in a highly characterized sample of children with poorly controlled asthma. We hypothesized that (1) children with asymptomatic gastroesophageal reflux determined by 24-hour esophageal pH monitoring would have a lower EBC pH than children without gastroesophageal reflux, (2) treatment with lansoprazole would alter EBC pH in those children, and (3) EBC acidification would be associated with increased asthma symptoms, poorer asthma control and quality of life, and increased formation of breath nitrogen oxides (NOx).

METHODS

A total of 110 children, age range 6 to 17 years, with poor asthma control and esophageal pH data enrolled in the Study of Acid Reflux in Children with Asthma (NCT00442013) were included. Children submitted EBC samples for pH and NOx measurement at randomization and at study weeks 8, 16, and 24.

RESULTS

Serial EBC pH measurements failed to distinguish asymptomatic gastroesophageal reflux and was not associated with breath NOx formation. EBC pH also did not discriminate asthma characteristics such as medication and health care utilization, pulmonary function, and asthma control and quality of life both at baseline and across the study period.

CONCLUSION

Despite the relative ease of EBC collection, EBC pH as a biomarker does not provide useful information of children with asthma who were enrolled in asthma clinical trials.

Diagnosis and management of eosinophilic asthma: a US perspective

Eosinophilic asthma is now recognized as an important subphenotype of asthma based on the pattern of inflammatory cellular infiltrate in the airway. Eosinophilic asthma can be associated with increased asthma severity, atopy, late-onset disease, and steroid refractoriness. Induced sputum cell count is the gold standard for identifying eosinophilic inflammation in asthma although several noninvasive biomarkers, including fractional exhaled nitric oxide and periostin, are emerging as potential surrogates. As novel therapies and biologic agents become increasingly available, there is an increased need for specific phenotype-directed treatment strategies. Greater recognition and understanding of the unique immunopathology of this asthma phenotype has important implications for management of the disease and the potential to improve patient outcomes. The present review provides a summary of the clinical features, pathogenesis, diagnosis, and management of eosinophilic asthma.

Bi-functional co-sensitization of graphene oxide sheets and Ir nanoparticles on p-type Co3O4 nanofibers for selective acetone detection

Highly sensitive and selective sensing composites that could detect acetone were obtained by a dual catalytic effect using Ir NPs and GO sheets, which is promising for the diagnosis of diabetes via exhaled breath.

Clinical utility of asthma biomarkers: from bench to bedside

Asthma is a chronic disease characterized by airway inflammation, bronchial hyperresponsiveness, and recurrent episodes of reversible airway obstruction. The disease is very heterogeneous in onset, course, and response to treatment, and seems to encompass a broad collection of heterogeneous disease subtypes with different underlying pathophysiological mechanisms. There is a strong need for easily interpreted clinical biomarkers to assess the nature and severity of the disease. Currently available biomarkers for clinical practice - for example markers in bronchial lavage, bronchial biopsies, sputum, or fraction of exhaled nitric oxide (FeNO) - are limited due to invasiveness or lack of specificity. The assessment of markers in peripheral blood might be a good alternative to study airway inflammation more specifically, compared to FeNO, and in a less invasive manner, compared to bronchoalveolar lavage, biopsies, or sputum induction. In addition, promising novel biomarkers are discovered in the field of breath metabolomics (eg, volatile organic compounds) and (pharmaco)genomics. Biomarker research in asthma is increasingly shifting from the assessment of the value of single biomarkers to multidimensional approaches in which the clinical value of a combination of various markers is studied. This could eventually lead to the development of a clinically applicable algorithm composed of various markers and clinical features to phenotype asthma and improve diagnosis and asthma management.

Biomarker surrogates do not accurately predict sputum eosinophil and neutrophil percentages in asthmatic subjects

BACKGROUND

Sputum eosinophil percentages are a strong predictor of airway inflammation and exacerbations and aid asthma management, whereas sputum neutrophil percentages indicate a different severe asthma phenotype that is potentially less responsive to TH2-targeted therapy. Variables, such as blood eosinophil counts, total IgE levels, fraction of exhaled nitric oxide (Feno) levels, or FEV1 percent predicted, might predict airway eosinophil percentages, whereas age, FEV1 percent predicted, or blood neutrophil counts might predict sputum neutrophil percentages. Availability and ease of measurement are useful characteristics, but accuracy in predicting airway eosinophil and neutrophil percentages either individually or combined is not established.

OBJECTIVES

We sought to determine whether blood eosinophil counts, Feno levels, and IgE levels accurately predict sputum eosinophil percentages and whether age, FEV1 percent predicted, and blood neutrophil counts accurately predict sputum neutrophil percentages.

METHODS

Subjects in the Wake Forest Severe Asthma Research Program (n = 328) were characterized by blood and sputum cell counts, health care use, lung function, Feno levels, and IgE levels. Multiple analytic techniques were used.

RESULTS

Despite significant association with sputum eosinophil percentages, blood eosinophil counts, Feno levels, and total IgE levels did not accurately predict sputum eosinophil percentages, and combinations of these variables did not improve prediction. Age, FEV1 percent predicted, and blood neutrophil counts were similarly unsatisfactory for the prediction of sputum neutrophil percentages. Factor analysis and stepwise selection found Feno levels, IgE levels, and FEV1 percent predicted, but not blood eosinophil counts, correctly predicted 69% of sputum eosinophil percentages of less than 2% or 2% and greater. Likewise, age, asthma duration, and blood neutrophil counts correctly predicted 64% of sputum neutrophil percentages of less than 40% or 40% and greater. A model to predict both sputum eosinophil and neutrophil percentages accurately assigned only 41% of samples.

CONCLUSION

Despite statistically significant associations, Feno levels, IgE levels, blood eosinophil and neutrophil counts, FEV1 percent predicted, and age are poor surrogates, both separately and combined, for accurately predicting sputum eosinophil and neutrophil percentages.

Clinical and anti-inflammatory effects of ultra-short preseasonal vaccine to Parietaria in asthma

OBJECTIVE

The ultra-short course preseasonal allergy vaccine, containing the adjuvant monophosphoryl lipid A (MPL), is effective in treating allergic symptoms; however, the efficacy in controlling asthmatics symptoms has not been fully demonstrated. We aimed at evaluating whether the ultra-short preseasonal course of immunotherapy contributes to asthma control.

METHODS

Four subcutaneous injections of the active product (Pollinex Quattro) were administered, before the pollen season, to 20 Parietaria-sensitive mild, untreated asthmatics (M/F: 12/8; age: 38 ± 14 years). After the screening visit (visit 1), asthma control was assessed by the Asthma Control Test (ACT) immediately before the first (visit 2) and immediately after the last (visit 5) injections, as well as during the pollen season (visit 6). Bronchial and alveolar exhaled nitric oxide (NO) concentrations were also measured. Nine Parietaria-sensitive mild asthmatics (M/F: 3/6; age: 40 ± 12 years) served as untreated controls.

RESULTS

The ACT remained constant during allergen exposure in specific immunotherapy (SIT)-treated asthmatics (visit 2: 22 ± 3.2; visit 5: 23 ± 2.8; visit 6: 22 ± 3.6; analysis of variance [ANOVA], p = 0.47), whereas it dropped during pollen exposure in controls (visit 2: 20 ± 2.5; visit 5: 21 ± 2.8; visit 6: 16 ± 5.7; ANOVA, p = 0.01). The forced expiratory NO (FENO) values significantly increased during pollen exposure in both groups; however, the alveolar NO concentrations remained stable in SIT-treated asthmatics (p = 0.11), whereas they doubled in controls (p = 0.01).

CONCLUSIONS

The current findings show that the preseasonal vaccine adjuvated with MPL contributes to the maintenance of control of asthma during the pollen season.

Secondhand smoke exposure induces acutely airway acidification and oxidative stress

Previous studies have shown that secondhand smoke induces lung function impairment and increases proinflammatory cytokines. The aim of the present study was to evaluate the acute effects of secondhand smoke on airway acidification and airway oxidative stress in never-smokers. In a randomized controlled cross-over trial, 18 young healthy never-smokers were assessed at baseline and 0, 30, 60, 120, 180 and 240 min after one-hour secondhand smoke exposure at bar/restaurant levels. Exhaled NO and CO measurements, exhaled breath condensate collection (for pH, H(2)O(2) and NO(2)(-)/NO(3)(-) measurements) and spirometry were performed at all time-points. Secondhand smoke exposure induced increases in serum cotinine and exhaled CO that persisted until 240 min. Exhaled breath condensate pH decreased immediately after exposure (p < 0.001) and returned to baseline by 180 min, whereas H(2)O(2) increased at 120 min and remained increased at 240 min (p = 0.001). No changes in exhaled NO and NO(2)/NO(3) were observed, while decreases in FEV(1) (p < 0.001) and FEV(1)/FVC (p < 0.001) were observed after exposure and returned to baseline by 180 min. A 1-h exposure to secondhand smoke induced airway acidification and increased airway oxidative stress, accompanied by significant impairment of lung function. Despite the reversal in EBC pH and lung function, airway oxidative stress remained increased 4 h after the exposure. Clinical trial registration number (EudraCT): 2009-013545-28.

Steroid-resistant asthma

Steroid-resistant asthma (SRA) refers to patients with symptoms consistent with asthma who show very poor or no response at all to high doses of inhaled or even of systemic corticosteroids. The current article reviews the SRA related literature focusing on the problems associated with the definition of SRA (especially its association with difficult to control, or severe asthma), its various phenotypes, its molecular basis, and the potential treatment options. The article also discusses the limitations of some of the key criteria used for the determination of SRA and proposes a modified set of criteria that are more applicable to children.

Breath biomarkers in diagnosis of pulmonary diseases

Breath analysis provides a convenient and simple alternative to traditional specimen testing in clinical laboratory diagnosis. As such, substantial research has been devoted to the analysis and identification of breath biomarkers. Development of new analytes enhances the desirability of breath analysis especially for patients who monitor daily biochemical parameters. Elucidating the physiologic significance of volatile substances in breath is essential for clinical use. This review describes the use of breath biomarkers in diagnosis of asthma, chronic obstructive pulmonary disease (COPD), cystic fibrosis (CF), lung cancer, as well as other pulmonary diseases. A number of breath biomarkers in lung pathophysiology will be described including nitric oxide (NO), carbon monoxide (CO), hydrogen peroxide (H₂O₂) and other hydrocarbons.

Biomarkers of therapy responsiveness in asthma: pitfalls and promises

Asthma is one of the most common chronic diseases worldwide. There is a large inter-individual variability in response to asthma treatment. Most patients respond well to standard therapy; however, a small proportion of the patients remain symptomatic despite treatment with high dosages of corticosteroids. Uncontrolled asthma leads to a decreased quality of life. Therefore, it is important to identify individuals who will respond poorly to standard asthma medication, especially to standard maintenance therapy with inhaled corticosteroids, at an early stage. Response to anti-inflammatory therapy is generally monitored by the assessment of clinical symptoms, which only partially correlates with underlying airway inflammation. The identification of specific inflammatory biomarkers might help to guide treatment or predict a corticosteroid response more accurately. Some inflammatory biomarkers are already finding their way into clinical practice (e.g. fraction of nitric oxide in exhaled breath), whereas others are predominantly used as a research tool (e.g. profiles of volatile organic compounds). Currently, there is no inflammatory biomarker used in routine clinical practice to predict a corticosteroid response. More knowledge on the underlying biological mechanism(s) of heterogeneous therapeutic responses could help to identify novel biomarkers. This review will focus on inflammatory patterns and genetic variations that may underlie differences in treatment response in patients with asthma, and will provide an overview of inflammatory biomarkers that could potentially serve as response predictors.

Exhaled breath condensate nitrates, but not nitrites or FENO, relate to asthma control

BACKGROUND

Asthma is a chronic respiratory disease, characterised by airways inflammation, obstruction and hyperresponsiveness. Asthma control is the goal of asthma treatment, but many patients have sub-optimal control. Exhaled NO and exhaled breath condensate (EBC) NO metabolites (nitrites and nitrates) measurements are non-invasive tools to assess airways inflammation. Our aim was to investigate the relationships between asthma control and the above-named biomarkers of airways inflammation.

METHODS

Thirty-nine non-smoking asthmatic patients (19 women) aged 50 (21-80) years performed measurements of exhaled NO (FENO), EBC nitrates, nitrites and pH, and answered Asthma Control Questionnaire (ACQ) and Asthma Control Test (ACT)-questionnaire.

RESULTS

The ACT and ACQ score were strongly interrelated (ρ = -0.84, p < 0.001). No relationships between ACT or ACQ score and FENO were found (p > 0.05). EBC nitrates were negatively related to ACT score (ρ = -0.34, p = 0.03) and positively related to ACQ score (ρ = 0.41, p = 0.001) while no relation of EBC nitrites to either ACQ or ACT score was found (p>0.05).

CONCLUSION

EBC nitrates were the only biomarker that was significantly related to asthma control. This suggests that nitrates, but not nitrites or FENO, reflect an aspect of airways inflammation that is closer related to asthma symptoms. Therefore there is a potential role for EBC nitrates in objective assessment of asthma control.

Increased levels of HMGB-1 and endogenous secretory RAGE in induced sputum from asthmatic patients

BACKGROUND

High mobility group box 1 (HMGB-1), a ligand of the receptor for advanced glycation end products (RAGE), is an inflammatory mediator in various disorders. Its endogenous decoy inhibitor, endogenous secretory RAGE (esRAGE), prevents the activation of RAGE signaling, and imbalance between HMGB-1 and esRAGE is known to be a factor determining progression of chronic inflammatory diseases.

METHODS

We measured HMGB-1 and esRAGE levels in induced sputum from 44 asthmatic patients and 15 normal controls, and examined their correlations with asthma indices including pulmonary function test values and induced sputum indices.

RESULTS

HMGB-1 levels in induced sputum were significantly higher in asthmatic patients than in normal controls (p < 0.001). Similarly, esRAGE levels were significantly higher in asthmatic patients than in normal controls (p < 0.001). In asthmatic patients, HMGB-1 levels were inversely correlated with percentage of predicted forced expiratory volume in 1 s (%FEV(1)) and FEV(1)/forced vital capacity (FEV(1)/FVC). There was a significant increase in HMGB-1 level associated with severity of asthma (p < 0.001). However, there was no significant increase in esRAGE level associated with severity of asthma. In asthmatic patients, HMGB-1 levels were significantly correlated with percentage of neutrophils in induced sputum.

CONCLUSIONS

Our findings suggest that the HMGB-1 is a mediator of neutrophilic airway inflammation in asthma and that imbalance between HMGB-1 and esRAGE is related to the severity of asthma. Combined measurement of HMGB-1 and esRAGE may be novel biomarkers in asthma with severe airflow limitation.