Increased macrophage-derived chemokine in exhaled breath condensate and plasma from children with asthma

BACKGROUND: Type 2 helper T lymphocyte-specific chemokines including macrophage-derived chemokine (MDC), thymus and activation-regulated chemokine (TARC) and eotaxin are important mediators for allergic airway inflammation. OBJECTIVE: We investigated whether these chemokines can be detected in exhaled breath condensate (EBC) and their relation to childhood asthma. METHODS: Asthmatics recruited from paediatric clinics of a university teaching hospital were classified into intermittent asthma (IA) and persistent asthma (PA) according to Global Initiative for Asthma guidelines. EBC was collected by a disposable collection kit, whereas fractional exhaled nitric oxide (FENO) was measured by a chemiluminescence analyser. Concentrations of MDC, TARC and eotaxin in both EBC and plasma were measured using sandwich enzyme immunoassay. The intra-subject reproducibility of exhaled chemokine measurements was determined by co-efficients of variation (CV). RESULTS: Forty-eight patients with PA, 36 children with IA and 18 controls were recruited. MDC and eotaxin were present in EBC from nearly all subjects, whereas TARC could be measured in EBC from 33 (32%) subjects only. The median MDC concentration in EBC was higher in PA (117 pg/mL) as compared with IA (106 pg/mL) and controls (105 pg/mL; P=0.003 for both). The median plasma MDC concentration in PA (648 pg/mL) was also higher than that in IA (520 pg/mL; P=0.002) and controls (490 pg/mL; P=0.008). The median plasma TARC concentration was also increased in PA as compared with IA (72 pg/mL vs. 35 pg/mL; P=0.004). MDC concentrations in EBC were lower in patients with PA who received high-dose inhaled corticosteroid (P=0.005). FENO was significantly higher in asthmatics than controls (P<0.0001), but it was not associated with chemokines in EBC or plasma. The mean (range) CV for measuring MDC, TARC and eotaxin in EBC (n=6) were 5.5 (2.0-7.2%), 8.8 (3.6-14.4%) and 5.2 (2.8-7.9%), respectively. CONCLUSIONS: Our results suggest that MDC in EBC and MDC and TARC in plasma are increased in children with PA as compared with IA or control. MDC concentrations in EBC are suppressed in patients on high-dose inhaled corticosteroid treatment.     

What did we learn from multiple omics studies in asthma?

More than a decade has passed since the finalization of the Human Genome Project. Omics technologies made a huge leap from trendy and very expensive to routinely executed and relatively cheap assays. Simultaneously, we understood that omics is not a panacea for every problem in the area of human health and personalized medicine. Whilst in some areas of research omics showed immediate results, in other fields, including asthma, it only allowed us to identify the incredibly complicated molecular processes. Along with their possibilities, omics technologies also bring many issues connected to sample collection, analyses and interpretation. It is often impossible to separate the intrinsic imperfection of omics from asthma heterogeneity. Still, many insights and directions from applied omics were acquired—presumable phenotypic clusters of patients, plausible biomarkers and potential pathways involved. Omics technologies develop rapidly, bringing improvements also to asthma research. These improvements, together with our growing understanding of asthma subphenotypes and underlying cellular processes, will likely play a role in asthma management strategies.     

The crosstalk between microbiome and asthma: Exploring associations and challenges

With the advancement of high‐throughput DNA/RNA sequencing and computational analysis techniques, commensal bacteria are now considered almost as important as pathological ones. Understanding the interaction between these bacterial microbiota, host and asthma is crucial to reveal their role in asthma pathophysiology. Several airway and/or gut microbiome studies have shown associations between certain bacterial taxa and asthma. However, challenges remain before gained knowledge from these studies can be implemented into clinical practice, such as inconsistency between studies in choosing sampling compartments and/or sequencing approaches, variability of results in asthma studies, and not taking into account medication intake and diet composition especially when investigating gut microbiome. Overcoming those challenges will help to better understand the complex asthma disease process. The therapeutic potential of using pro‐ and prebiotics to prevent or reduce risk of asthma exacerbations requires further investigation. This review will focus on methodological issues regarding setting up a microbiome study, recent developments in asthma bacterial microbiome studies, challenges and future therapeutic potential.     

Oxidative stress and airway inflammation after allergen challenge evaluated by exhaled breath condensate analysis

Background Allergen exposure may increase airway oxidative stress, which causes lipid membrane peroxidation and an increased formation of 8‐isoprostane. Objective The aim of the study was to investigate oxidative stress induced by allergen challenge in mild asthmatics, by measuring 8‐isoprostane in exhaled breath condensate (EBC), and to examine their relationship with mediators derived from arachidonic acid. Methods 8‐isoprostane, cysteinyl leukotrienes (cys‐LTs) and prostaglandin E2 (PGE₂) concentrations in EBC were measured at baseline and after allergen challenge in 12 patients with mild allergic asthma sensitized to cat allergen. Results At 24 h after allergen challenge, compared with baseline values, EBC 8‐isoprostane increased [48.64 pg/mL (44.14–53.61) vs. 21.56 pg/mL (19.92, 23.35), P<0.001], cys‐LTs increased [27.37 pg/mL (24.09–31.10) vs. 13.28 pg/mL (11.32, 15.57), P<0.001] and PGE₂ decreased [18.69 pg/mL (12.26, 28.50) vs. 39.95 pg/mL (34.37, 46.43), P<0.001]. The trend of increasing 8‐isoprostane after allergen challenge was significantly correlated with the trend of increasing cys‐LTs (R²=0.85, P<0.001) whereas the trend of decreasing PGE₂ after allergen challenge was significantly correlated with the trend of increasing cys‐LTs (R²=0.52, P=0.001). Conclusions and Clinical Relevance The increase in EBC 8‐isoprostane observed after allergen challenge indicates that allergen exposure increases airway oxidative stress in allergic asthma. The strict correlation between cys‐LTs and 8‐isoprostane underlines the relationship between allergic inflammation and oxidative stress. A shift of arachidonic acid metabolism towards lipoxygenase pathway is induced by the allergen challenge. Airway oxidative stress occurs after allergen challenge even in patients with mild intermittent allergic asthma. Cite this as: L. Brussino, I. Badiu S. Sciascia, M. Bugiani, E. Heffler G. Guida, A. Malinovschi, C. Bucca and G. Rolla, Clinical & Experimental Allergy, 2010 (40) 1642–1647.     

Persistence of rhinovirus RNA after asthma exacerbation in children

BACKGROUND: Rhinoviruses (RVs) are believed to cause most asthma exacerbations but their role in the severity of acute asthma and subsequent recovery of airway function is not defined. The importance of atopy in virus-host interactions is also not clear. OBJECTIVE: We postulated that RV infection and atopic skin prick responses influence the severity of asthma exacerbations as measured by peak expiratory flow (PEF). METHODS: Patients aged 4-12 years admitted with acute severe asthma to a hospital emergency room (ER) were recruited. PEF measurements were obtained and nasal aspirates (NA) were taken. Atopy was diagnosed by skin prick responses to allergen and the presence of RV RNA and respiratory syncytial virus (RSV) RNA in NAs was detected using validated PCR assays. Patients were restudied after 6 weeks and after 6 months. RESULTS: Fifty children with acute asthma (mean age+/-SD, 7.4+/-2.7) were enrolled; atopy was present in 37 (74%). RV RNA was detected in 41 (82%) and RSV RNA in six (12%) subjects. After 6 weeks 41 patients were restudied and RV RNA was again detected in 18 (44%). RV RNA was detected after 6 months in four of 16 patients restudied (25%; P=0.008 vs. ER) and in two of nine children from a control group with stable asthma (22%; P=0.009 vs. ER). Overall PEF measurements were reduced in asthmatics admitted to ER (% predicted, 63.4+/-16.4%) but did not differ between patients with RV RNA, RSV RNA or neither virus present. In subjects with RV RNA detectable in ER and after 6 weeks, measurements of PEF in ER were significantly lower than in patients in whom RV RNA was present in ER but absent after 6 weeks (P=0.009). Regression analysis linked persistence of RV RNA, but not skin prick responses to allergen, to severity of PEF reductions in ER. CONCLUSION: RV RNA was detectable in >40% of asthmatic children 6 weeks after an acute exacerbation. Asthma exacerbations were more severe in patients with persistence of RV RNA suggesting that the severity of acute asthma may be linked to prolonged and possibly more severe RV infections.     

Similar levels of nitric oxide in exhaled air in non-asthmatic rhinitis and asthma after bronchial allergen challenge

BACKGROUND: Nitric oxide in exhaled air (eNO) is elevated in allergic asthma compared with healthy subjects and has been proposed as a marker of bronchial inflammation. However, eNO is elevated to a lesser extent in allergic non-asthmatic rhinitis as well. Considering the distinctive clinical appearances of both allergic diseases, differences in eNO are expected to persist after allergen exposure. The aim of the study was to compare allergen-induced changes in eNO in house dust mite sensitized patients with asthma and patients with perennial rhinitis without asthma symptoms. METHODS: Bronchial allergen challenge was performed in 52 patients sensitized to house dust mite (Dermatophagoides pteronyssinus), of whom 26 had non-asthmatic rhinitis and 26 had asthma. Levels of eNO were measured before and 1 h, 1 day and 1 week after challenge. RESULTS: At baseline eNO was significantly lower in non-asthmatic rhinitis compared with asthma (geometric mean eNO (SEM): 121 (1.1) in non-asthmatic rhinitis vs 197 (1.1) nl/min in asthma, P < 0.006). However, the increase in eNO after bronchial allergen challenge in non-asthmatic rhinitis, in particular in those patients with a dual asthmatic response, significantly exceeded the increase in asthma resulting in similar levels of eNO after challenge (geometric mean eNO (SEM) at 24 h postchallenge 204 (1.1) in non-asthmatic rhinitis vs 244 (1.1)nl/min in asthma, P = 0.3). CONCLUSION: The difference in eNO between non-asthmatic rhinitis and asthma at baseline is abolished after allergen exposure due to a significantly greater increase in eNO in non-asthmatic rhinitis.     

Effect of inhalation aspirin challenge on exhaled nitric oxide in patients with aspirin-inducible asthma

BACKGROUND: A complex relationship between arachidonic acid metabolites and nitric oxide (NO) synthesis has been reported in asthma. The effects of inhaled aspirin on fractional exhaled NO (FENO) in patients with aspirin-tolerant (ATA) and aspirin-inducible (AIA) asthma compared with normal controls have been investigated. METHODS: The FENO was measured baseline, after saline and lysine-aspirin (L-ASA) bronchial challenge in 10 patients with ATA and in 10 patients with AIA [mean (PD(20)FEV(1) L-ASA): 14.7 +/- 12.7 mg], who had comparable age and baseline FEV(1). Ten healthy subjects served as controls. Sputum eosinophils were counted after saline and after L-ASA challenge in the two groups of asthmatics. RESULTS: Asthmatic patients had baseline FENO significantly higher than controls (29.7 +/- 6.8 vs 9.8 +/- 2.05 p.p.b. respectively, P < 0.0001). No difference was observed in methacholine PD(20)FEV(1) and baseline FENO between ATA and AIA patients. After L-ASA inhalation, FENO increased significantly only in patients with AIA, reaching the peak value 4 h after bronchoconstriction (from 31.1 +/- 6 to 43 +/- 4.8 p.p.b., P < 0.001), while no change was observed in patients with ATA and in controls. Sputum eosinophils increased significantly after L-ASA inhalation only in patients with AIA (from 8.1 +/- 2.7 to 11.1 +/- 2.8%, P < 0.005) and there was a significant relationship between the increase in sputum eosinophils and the increase in FENO after ASA challenge. CONCLUSION: Exhaled NO may indicate eosinophilic airway inflammation during ASA exposure in patients with ASA inducible asthma.     

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.     

Increased cytokines,chemokines and soluble adhesion molecules in exhaled breath condensate of asthmatic children

Background Airway inflammation in asthma is characterized by the production of cytokines, chemokines and soluble adhesion molecules. The assessment of these inflammatory biomarkers in exhaled breath condensate (EBC) is hampered by low detection rates. However, the use of a glass condenser system combined with a sensitive analytical technique may increase the possibility to assess these biomarkers in EBC in a reliable way. Objective (1) To assess the detection rates of cytokines (IL‐1α, ‐1β, ‐2, ‐4, ‐5, ‐6, ‐10, ‐12p70, ‐13, ‐18, IFN‐γ, TNF‐α), chemokines [MIP1α (CCL3), MIF, eotaxin (CCL11), RANTES (CCL5), IP10 (CXCL10), IL8 (CXCL8), MCP1] and soluble adhesion molecules [soluble intercellular adhesion molecule (sICAM), soluble vascular adhesion molecule (sVCAM)] in EBC of children with asthma and healthy control children;
(2) To study the differences in the biomarker concentration between children with asthma and controls. Methods Sixty children were included: 31 asthmatics (71% atopic) and 29 controls. Exhaled breath condensate was collected using a glass condenser system. The inflammatory markers (IM) were analysed using multiplex immunoassay technology. Results Detection percentages of cytokines, chemokines and adhesion molecules ranged from 94% to 100%, except for eotaxin (CCL11) and RANTES (CCL5) (detection rates of 10% and 45% in healthy controls, respectively). The intra‐subject variability of biomarkers in EBC in the group as a whole ranged from 5.2% to 35.0%. In asthmatics, the levels of cytokines (IL‐2, ‐4, ‐5, ‐6, ‐13, IFN‐γ), chemokines (MIP1α [CCL3], MIF, RANTES [CCL5], IP10 [CXCL10], IL8 [CXCL8], MCP1) and adhesion molecules (sICAM, sVCAM) were significantly increased in comparison with controls (P<0.05). Conclusion If collected with a glass condenser and analysed by multiplex immunoassay technology, cytokines, chemokines and soluble adhesion molecules can be reliably demonstrated in EBC of children. Most of these IM were elevated in EBC of asthmatics compared with controls. Cite this as: C. M. H. H. T. Robroeks, G. T. Rijkers, Q. Jöbsis, H. J. E. Hendriks, J. G. M. C. Damoiseaux, L. J. I. Zimmermann, O. P. van Schayck, E. Dompeling, Clinical & Experimental Allergy, 2010 (40) 77–84.     

Increased eosinophil transmigration after nasal allergen challenge in children with allergic asthma and rhinitis

BACKGROUND: Eotaxin and interleukin-5 together provide the signal essential for eosinophil transmigration to airway tissue in allergic reactions. However, it is not known whether peripheral blood eosinophils (PBE) possess an increased transmigration capacity in vitro after allergen challenge in vivo before they leave the circulation. We aimed to determine whether PBE in cat-sensitized children have increased spontaneous and/or eotaxin-induced transmigration capacity in vitro, and to what extent allergen challenge alters this feature. METHODS: Fourteen cat-allergic children and four healthy controls underwent nasal challenge with cat-allergen. Blood samples were drawn prechallenge and at 2 h and 24 h postchallenge. We analyzed the in vitro transmigration of PBE, with and without eotaxin as a chemoattractant. We used a transmigration assay with fibronectin-coated membranes. Eosinophil cationic protein (ECP) and PBE counts were run in parallel. RESULTS: The spontaneous transmigration capacity of eosinophils in vitro was significantly higher at 2 h after allergen challenge (P < 0.01 vs. prechallenge) and returned to prechallenge levels at 24 h postchallenge (P < 0.02 vs. 2 h postchallenge). Addition of eotaxin further augmented the increased transmigration. In concordance, no accompanying changes were measured in the levels of eosinophils in blood or ECP in serum. Furthermore no spontaneous or eotaxin-induced eosinophil transmigration was detected in healthy controls. CONCLUSION: PBE possess increased spontaneous (and eotaxin-induced) capacity to transmigrate as early as 2 h after allergen challenge in allergic children, without accompanying signs of eosinophil activation in terms of increased PBE count or ECP level. This is probably due to the increased stage of activation of the eosinophil, often referred to as "priming".     

Increased lymphoid MxA expression in acute asthma exacerbation in children

BACKGROUND: Although the association between acute asthma exacerbation and viral infection has been well documented, virus identification rates vary. It has recently been reported that the expression of MxA protein in lymphocytes, inducible by type I interferons, can serve as a sensitive marker for viral infection in the host. The objective was to determine the contribution of viral infection to precipitation of asthma attacks in children. METHODS: We studied 186 asthmatic children, aged 0-12 years, over a 1-year period to evaluate MxA protein levels in peripheral blood lymphocytes by using a flow cytometric analysis in whole blood. RESULTS: Of all the subjects, 80 (47%) exhibited significantly elevated levels of MxA expression in lymphocytes, presumably indicating the states of viral infection. The association of viral infections with acute asthma exacerbation seemed to be marked in younger children: enhanced MxA expression was seen in 73.3% of infants (aged 0-1 year), 49.5% of toddlers (aged 2-5 years), and 26% of schoolchildren (aged 6-12 years). Seasonal changes in the frequency of viral infection associated with deterioration were also observed. CONCLUSIONS: Flow cytometric assay of MxA protein expression in whole blood appears to be an easy and useful method to evaluate viral infections in acute asthma exacerbation.     

Airway inflammation and eotaxin in exhaled breath condensate of patients with severe persistent allergic asthma during omalizumab therapy

PurposeThe central role of IgE in allergic inflammation in asthma has provided a rationale for the development of omalizumab, the humanized monoclonal anti-IgE antibody. The aim of the study was to determine the effect of omalizumab treatment on changes in airway inflammatory process and eotaxin in exhaled breath condensate in patients with persistent severe allergic asthma.Material and MethodsThe study was performed on a group of 19 patients with severe persistent allergic asthma treated with conventional therapy (according to GINA 2006) and with or without omalizumab (9 vs 10 patients). Eotaxin in exhaled breath condensate, exhaled nitric oxide, blood eosinophil count and serum ECP were measured before and after 16 weeks of therapy.ResultsIn the group treated with omalizumab, a statistically significant decrease in the concentrations of eotaxin in EBC, FENO, serum ECP, and blood eosinophil count after 16 weeks of treatment was observed. Statistically significant correlations were revealed between the decrease in eotaxin and the decrease in FENO, serum ECP and blood eosinophil count after omalizumab therapy.ConclusionsDownregulation of eotaxin expression in the airways through limitation of eosinophilic inflammation could be essential in the beneficial effect of anti-IgE therapy with omalizumab in asthma patients.