Eotaxin-1 in exhaled breath condensate of stable and unstable asthma patients

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.

Antioxidant Intake and Biomarkers of Asthma in Relation to Smoking Status-A Review

Asthma is considered a chronic inflammatory disorder associated with airway hyperresponsiveness (AHR). Increased oxidative stress (OS) is a clinical feature of asthma, which promotes the inflammatory responses in bronchial/airway epithelial cells. Smokers and nonsmokers with asthma have been shown to have increases in several OS and inflammatory biomarkers. However, studies suggest significant differences in OS and inflammation biomarkers between smokers and nonsmokers. A few studies suggest associations between antioxidant intake from diet/supplements and asthma in patients with different smoking status. Evidence is lacking on the protective role of antioxidant vitamin and/or mineral consumption against asthma by smoking status with respect to inflammation and OS biomarkers. Therefore, the aim of this review is to highlight current knowledge regarding the relations between antioxidant intake, asthma, and its associated biomarkers, according to smoking status. This paper can be used to guide future research directions towards the health consequences of antioxidant intake in smoking and nonsmoking asthmatics.

Wentong decoction cures allergic bronchial asthma by regulating the apoptosis imbalance of EOS

Background

Eosinophils (EOS) is one of the most important cells involved in the pathogenesis of chronic airway inflammation in asthma, and its apoptosis is part of the mechanisms of asthma. Therefore, this study aimed to observe the effect of Chinese medicine Wentong decoction (WTD) in EOS apoptosis in asthmatic rats. This work also explored the mechanism of WTD regulation in EOS apoptosis and provided a new target for clinical treatment of asthma.

Methods

Asthmatic rats induced by ovalbumin were treated with WTD. Lung function of rats in each group was detected, and lung tissue pathology, EOS counts in blood and bronchoalveolar lavage fluid were observed. The degree of the EOS apoptosis in rats was detected. The expression content of interleukin (IL)-5, IL-10, chemokine (C-C motif) ligand 5 (CCL5), granulocyte-macrophage colony-stimulating factor (GM-CSF), transforming growth factor beta 1 (TGF-β1), interferon (IFN)-γ, and other cytokines in rat serum and the genes of Eotaxin mRNA, Fas mRNA, FasL mRNA, Fas/FasL and Bcl-2 mRNA in the lung tissues were determined.

Results

WTD can reduced airway resistance in rat models and improved airway compliance. The pathological changes of lung tissue in WTD group were significantly alleviated, at the same time, WTD could reduce the EOS count in the blood and BALF smears of the asthmatic model rats. Compared with the model group, the apoptosis degree of EOS significantly increased in rats in the WTD group. The expression of IL-5, CCL5, and GM-CSF in the serum and the expression of Eotaxin mRNA, Bcl-2 mRNA in the lung tissues in rats in the WTD group rats decreased. Moreover, the expression of IL-10, TGF-β1, and IFN-γ in the serum and the expression of Fas mRNA, FasL mRNA in the lung tissues in rats in the WTD group rats increased compared with that in rats in the model group.

Conclusions

Wentong decoction may accelerate EOS apoptosis, reduce asthma inflammation, and alleviate the disease through regulating and controlling the factors related to the anti-apoptosis and pro-apoptosis.

Severe bronchial asthma in children: a review of novel biomarkers used as predictors of the disease

Severe asthma or therapy-resistant asthma in children is a heterogeneous disease that affects all age-groups. Given its heterogeneity, precision in diagnosis and treatment has become imperative, in order to achieve better outcomes. If one is thus able to identify specific patient phenotypes and endotypes using the appropriate biomarkers, it will assist in providing the patient with more personalized and appropriate treatment. However, there appears to be a huge diagnostic gap in severe asthma, as there is no single test yet that accurately determines disease phenotype. In this paper, we review the published literature on some of these biomarkers and their possible role in bridging this diagnostic gap. We also highlight the cellular and molecular mechanisms involved in severe asthma, in order to show the basis for the novel biomarkers. Some markers useful for monitoring therapy and assessing airway remodeling in the disease are also discussed. A review of the literature was conducted with PubMed to gather baseline data on the subject. The literature search extended to articles published within the last 40 years. Although biomarkers specific to different severe asthma phenotypes have been identified, progress in their utility remains slow, because of several disease mechanisms, the variation of biomarkers at different levels of inflammation, changes in relying on one test over time (eg, from sputum eosinophilia to blood eosinophilia), and the degree of invasive tests required to collect biomarkers, which limits their applicability in clinical settings. In conclusion, several biomarkers remain useful in recognizing various asthma phenotypes. However, due to disease heterogeneity, identification and utilization of ideal and defined biomarkers in severe asthma are still inconclusive. The development of novel serum/sputum-based biomarker panels with enhanced sensitivity and specificity may lead to prompt diagnosis of the disease in the future.

The Flavonoid 7,4'-Dihydroxyflavone Prevents Dexamethasone Paradoxical Adverse Effect on Eotaxin Production by Human Fibroblasts

Eotaxin/CCL-11 is a major chemoattractant that contributes to eosinophilic inflammation in asthma. Glucocorticoids inhibit inflammation, but long-time exposure may cause paradoxical adverse effects by augmenting eotaxin/CCL-11production. The aim of this study was to determine if 7,4'-dihydroxyflavone (7,4'-DHF), the eotaxin/CCL11 inhibitor isolated from Glycyrrhiza uralensis, reduces in vitro eotaxin production induced by long-time dexamethasone (Dex) exposure, and if so, to elucidate the mechanisms of this inhibition. Human lung fibroblast-1 cells were used to identify the potency of 7,4'-DHF compared with other compounds from G. uralensis, to compare 7,4'-DHF with Dex on eotaxin production following 24-h short-time culture and 72-h longer-time (LT) culture, and to determine the effects of the 7,4'-DHF on Dex LT culture augmented eotaxin production and molecule mechanisms. 7,4'-DHF was the most potent eotaxin/CCL-11 inhibitor among the ten compounds and provided continued suppression. In contrast to short-time culture, Dex LT culture increased constitutively, and IL-4/TNF-α stimulated eotaxin/CCL11 production by human lung fibroblast-1 cells. This adverse effect was abrogated by 7,4'-DHF co-culture. 7,4'-DHF significantly inhibited Dex LT culture augmentation of p-STAT6 and impaired HDAC2 expression. This study demonstrated that 7,4'-DHF has the ability to consistently suppress eotaxin production and prevent Dex-paradoxical adverse effects on eotaxin production. Copyright © 2017 John Wiley & Sons, Ltd.

Current and future biomarkers in allergic asthma

Diagnosis early in life, sensitization, asthma endotypes, monitoring of disease and treatment progression are key motivations for the exploration of biomarkers for allergic rhinitis and allergic asthma. The number of genes related to allergic rhinitis and allergic asthma increases steadily; however, prognostic genes have not yet entered clinical application. We hypothesize that the combination of multiple genes may generate biomarkers with prognostic potential. The current review attempts to group more than 161 different potential biomarkers involved in respiratory inflammation to pave the way for future classifiers. The potential biomarkers are categorized into either epithelial or infiltrate-derived or mixed origin, epithelial biomarkers. Furthermore, surface markers were grouped into cell-type-specific categories. The current literature provides multiple biomarkers for potential asthma endotypes that are related to T-cell phenotypes such as Th1, Th2, Th9, Th17, Th22 and Tregs and their lead cytokines. Eosinophilic and neutrophilic asthma endotypes are also classified by epithelium-derived CCL-26 and osteopontin, respectively. There are currently about 20 epithelium-derived biomarkers exclusively derived from epithelium, which are likely to innovate biomarker panels as they are easy to sample. This article systematically reviews and categorizes genes and collects current evidence that may promote these biomarkers to become part of allergic rhinitis or allergic asthma classifiers with high prognostic value.

Intranasal Administration of Recombinant Mycobacterium smegmatis Inducing IL-17A Autoantibody Attenuates Airway Inflammation in a Murine Model of Allergic Asthma

Asthma is a chronic inflammatory disorder, previous studies have shown that IL-17A contributes to the development of asthma, and there is a positive correlation between the level of IL-17A and the severity of disease. Here, we constructed recombinant Mycobacterium smegmatis expressing fusion protein Ag85A-IL-17A (rMS-Ag85a-IL-17a) and evaluated whether it could attenuate allergic airway inflammation, and further investigated the underlying mechanism. In this work, the murine model of asthma was established with ovalbumin, and mice were intranasally vaccinated with rMS-Ag85a-IL-17a. Autoantibody of IL-17A in sera was detected, and the airway inflammatory cells infiltration, the local cytokines and chemokines production and the histopathological changes of lung tissue were investigated. We found that the administration of rMS-Ag85a-IL-17a induced the autoantibody of IL-17A in sera. The vaccination of rMS-Ag85a-IL-17a remarkably reduced the infiltration of inflammatory cells and the secretion of mucus in lung tissue and significantly decreased the numbers of the total cells, eosinophils and neutrophils in BALF. Th1 cells count in spleen, Th1 cytokine levels in BALF and supernatant of splenocytes and mediastinal lymph nodes, and T-bet mRNA in lung tissue were significantly increased with rMS-Ag85a-IL-17a administration. Meanwhile, rMS-Ag85a-IL-17a vaccination markedly decreased Th2 cells count, Th2 cytokine and Th17 cytokine levels in BALF and supernatant of splenocytes and mediastinal lymph nodes, and chemokines mRNA expression in lung tissue. These data confirmed that recombinant Mycobacterium smegmatis in vivo could induce autoantibody of IL-17A, which attenuated asthmatic airway inflammation.

Increased Levels of Interleukin-33 and Thymic Stromal Lymphopoietin in Exhaled Breath Condensate in Chronic Bronchial Asthma

BACKGROUND

Epithelium-derived cytokines such as thymic stromal lymphopoietin (TSLP), interleukin (IL)-25, and IL-33 are important contributors to inflammation in asthma. Exhaled breath condensate (EBC) is a noninvasive method used to assess the inflammation of airways. Our aim was to assess the levels of TSLP, IL-25, IL-33, and its receptor ST2l/IL-1 R4 in EBC in patients with asthma and to correlate these with serum levels and asthma control.

METHODS

EBC and serum levels of TSLP, IL-25, IL-33, and ST2l/IL-1 R4 were measured in 44 patients with chronic bronchial asthma (14 in the uncontrolled phase) and 19 healthy control participants.

RESULTS

EBC levels of IL-33 and TSLP and serum levels of IL-33 were statistically higher in patients with asthma than in controls. IL-25 and ST2l/IL-1 R4 were present in EBC at barely detectable levels and were not analyzed. The EBC and serum levels of all studied mediators did not differ between controlled and uncontrolled asthma patients, except for the serum level of ST2l/IL-1 R4, which was higher in uncontrolled asthma. There were no correlations between serum and EBC levels of TSLP and IL-33 or between either serum and EBC levels and the forced expiratory volume in 1 s or the total IgE level.

CONCLUSIONS

Higher levels of IL-33 and TSLP in EBC provide evidence supporting a role for these mediators in asthma. Their levels do not discriminate between controlled and uncontrolled asthma. The local reaction within the epithelium is independent of the systemic reaction.

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.

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.

Asthma diagnosis and severity monitoring in primary school children: essential role of sequential testing of exhaled nitric oxide

BACKGROUND

Chronic eosinophilic airway inflammation, airflow limitation, and airway hyper-responsiveness are the mainstays of asthma diagnosis. The increased levels of exhaled nitric oxide (FeNO) in asthma are closely related to the extent of airway inflammation. Sequential measurement of FeNO concentrations may accurately predict asthma severity and guide therapeutic decisions.

METHODS

A total of 22,083 grade 1 students in Taipei city primary schools were screened for wheezing episodes using the International Study of Asthma and Allergies in Childhood questionnaire (ISAAC) questionnaires while their sero-atopic conditions were confirmed by Fluorescent Enzyme Immune Assay (FEIA). All students with allergies were tested by FeNO electrochemical test. 100 age-matched healthy students were used as control group (FeNO levels<25ppb).

RESULTS

From the 2650 students (12%) initially included via the wheezing criteria, 2065 (78.0%) were confirmed to have allergy by FEIA (sensitisation to at least two common aero-allergens in Taiwan) and diagnosed by a paediatric allergologist. Among them, 1852 (89.6%) had elevated FeNO values (>25ppb) and 266 (10%) had FeNO values<25ppb. Using the GINA guidelines, 140 mild-to-moderate asthma students who had received inhaled corticosteroids (ICS) with or without Singulair treatment completed serial FeNO testing every three months for one year. The FeNO levels decreased in 121 students (86.4%) and increased in 19 students (13.6%), which was compatible to changing childhood asthma control score and response to step-down treatment, respectively.

CONCLUSION

FeNO is an easy, used non-invasive tool for the diagnosis of allergic asthma. Sequential FeNO testing can accurately reflect asthma severity and provide for successful stepwise therapy for asthmatic children.

CCL11 as a potential diagnostic marker for asthma?

OBJECTIVE

Asthma is an inflammatory airway disease characterized by airway eosinophilia, in which CCL11 (eotaxin) plays a crucial role. The aim of study is to determine the elevation of CCL11 levels in bronchoalveolar lavage fluid (BALF), blood, exhaled breath condensate (EBC) and sputum in asthma patients and to identify which medium yields the most significant change in CCL11 level.

METHODS

The databases of PubMed, Embase and Cochrane Centre Register of Controlled Trials were systematically searched from inception to September 2013. Controlled clinical trials that focused on CCL11 concentrations in asthma patients and controls, and their correlations with other asthma indicators were obtained. Data were analysed using Stata 12.0.

RESULTS

Thirty studies were included in this investigation. CCL11 levels in blood, EBC and sputum were significantly higher in asthma patients than in healthy subjects. Sputum CCL11 concentrations were significantly elevated in unstable asthma patients versus stable asthma patients and in uncontrolled asthma patients versus partially controlled asthma patients. CCL11 levels in sputum and blood were negatively correlated with the lung function as measured by FEV1% predicted, and were positively correlated with BALF, EBC and sputum eosinophil counts. Similarly, CCL11 concentrations were positively correlated with eosinophil cationic protein in EBC, blood and sputum as well as with interleukin-5 in sputum and fractional exhaled nitric oxide in EBC. Steroid treatment had no significant effect on CCL11 levels.

CONCLUSIONS

CCL11 is a potentially useful biomarker for the diagnosis and assessment of asthma severity and control, especially in sputum. CCL11 is crucial in eosinophil chemoattraction and activation in asthma pathogenesis. Further studies using anti-CCL11 approaches are needed to confirm a role for CCL11 in asthma pathogenesis particularly in patients with more severe disease.

Clinical Significance of the Dynamic Changes in Serum Eotaxin, Interleukin 13 and Total IgE in Children with Bronchial Asthma

OBJECTIVE

To determine the serum levels of eotaxin, IL-13 and total IgE (TIgE) in asthmatic children during the acute and clinical remission periods, as well as the changes in pulmonary function to determine their roles, relationships and clinical significance during asthma exacerbation.

METHODS

A total of 30 asthmatic children and 22 healthy children were enrolled in the study. The serum eotaxin and IL-13 levels were detected using an enzyme-linked immunosorbent assay and the TIgE level was detected using a fluorescent enzyme-linked immunosorbent assay. The asthmatic children were subjected to pulmonary function tests.

FINDINGS

The serum eotaxin, IL-13 and TIgE levels of the asthmatic children during the acute period significantly differed from those during clinical remission. The serum eotaxin, IL-13 and TIgE levels of the asthmatic children during both periods significantly differed from those of healthy children (P<0.001). The serum eotaxin levels during the acute and clinical remission periods were positively correlated with serum IL-13 and with TIgE, and serum IL-13 was correlated with serum TIgE. The pulmonary function indices of asthmatic children during the acute period significantly differed from those during clinical remission (P<0.001). The serum eotaxin and IL-13 levels in the asthmatic children were positively correlated with the forced expiratory volume in 1 second (FEV1) and the peak expiratory flow (PEF) during the acute and clinical remission periods (P<0.05). However, the serum TIgE levels in asthmatic children were not significantly correlated with the FEV1 and PEF during both periods (P>0.05).

CONCLUSION

Serum TIgE, IL-13 and eotaxin influence each other during exacerbation of bronchial asthma and influence the corresponding pathophysiologic changes. Serum IL-13 and eotaxin could be used as markers for evaluating the severity of bronchial asthma.

Recent advances in asthma biomarker research

Asthma is characterized by recurrent and reversible airflow obstruction, which is routinely monitored by history and physical examination, spirometry and home peak flow diaries. As airway inflammation is central to asthma pathogenesis, its monitoring should be part of patient management plans. Fractional exhaled nitric oxide level (FeNO) is the most extensively studied biomarker of airway inflammation, and FeNO references were higher in Chinese (Asians) than Whites. Published evidence was inconclusive as to whether FeNO is a useful management strategy for asthma. Other biomarkers include direct (histamine, methacholine) and indirect (adenosine, hypertonic saline) challenges of bronchial hyperresponsiveness (BHR), induced sputum and exhaled breath condensate (EBC). A management strategy that normalized sputum eosinophils among adult patients resulted in reductions of BHR and asthma exacerbations. However, subsequent adult and pediatric studies failed to replicate these benefits. Asthma phenotypes as defined by inflammatory cell populations in sputum were also not stable over a 12-month period. A recent meta-analysis concluded that induced sputum is not accurate enough to be applied in routine monitoring of childhood asthma. There is poor correlation between biomarkers that reflect different asthma dimensions: spirometry (airway caliber), BHR (airway reactivity) and FeNO or induced sputum (airway inflammation). Lastly, EBC is easily obtained noninvasively by cooling expired air. Many biomarkers ranging from acidity (pH), leukotrienes, aldehydes, cytokines to growth factors have been described. However, significant overlap between groups and technical difficulty in measuring low levels of inflammatory molecules are the major obstacles for EBC research. Metabolomics is an emerging analytical method for EBC biomarkers. In conclusion, both FeNO and induced sputum are useful asthma biomarkers. However, they will only form part of the clinical picture. Longitudinal studies with focused hypotheses and well-designed protocols are needed to establish the roles of these biomarkers in asthma management. The measurement of biomarkers in EBC remains a research tool.

Morphological changes in eosinophils are reliable markers of the severity of an acute asthma exacerbation in children

BACKGROUND

Early identification of the severity of asthma exacerbation would be helpful for the management of patients. We aimed to evaluate the correlation of morphological change in activated eosinophils and the severity of an asthma exacerbation.

METHODS

Blood was collected from 55 asthmatic children: 40 of whom were having an exacerbation, 15 symptom-free, and 15 healthy controls. The percentage of eosinophils with morphological changes (emission of single or multiple pseudopods, presence of cytoplasmic vacuoles, releasing a small, moderate, or large quantity of granules, spreading, eosinophil death, and presence of cluster of free eosinophil granules) was quantified after the adherence to a slide and compared using the Mann-Whitney test. The correlation between the severity of the asthma exacerbation and the percentage changed eosinophils was tested with Spearman's correlation.

RESULTS

The proportion of activated eosinophils was higher in asthmatic symptom-free children than in the control group, and acute asthma exacerbation produced an additional increase in eosinophil activation (P < 0.01). More significantly increased morphological changes were emissions of multiple pseudopods, presence of cytoplasmic vacuoles, spreading, and presence of a cluster of free eosinophil granules (P < 0.001). The following were correlated with the severity of an asthma exacerbation: ≥14% of eosinophils emitting single pseudopod, 8% emitting multiple pseudopods, 17% with vacuoles, 28% eosinophils releasing a large quantity of granules, and 66% of spread eosinophils.

CONCLUSIONS

Quantifying the morphological changes in eosinophils is a feasible, easy, and reliable manner to identify the severity of an asthma exacerbation and therefore might improve the clinical management of asthmatic children.

Eotaxin/CCL11 in idiopathic retroperitoneal fibrosis

BACKGROUND

Idiopathic retroperitoneal fibrosis (IRF) is a rare fibro-inflammatory disorder characterized by a periaortic tissue which often encases the ureters causing acute renal failure. IRF histology shows fibrosis and a chronic inflammatory infiltrate with frequent tissue eosinophilia. We assessed a panel of molecules promoting eosinophilia and fibrosis in IRF patients and performed an immunogenetic study.

METHODS

Serum levels of eotaxin/CCL11, regulated and normal T-cell expressed and secreted (RANTES), granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-5, platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) were measured using a multiplex assay in 24 newly diagnosed, untreated IRF patients and 14 healthy controls. Retroperitoneal biopsies (available in 8/24 patients) were histologically evaluated to assess eosinophil infiltration, whereas mast cells (MCs) were identified by immunohistochemical analysis for human tryptase. Immunohistochemistry for eotaxin/CCL11 and its receptor CCR3 was also performed. Six single nucleotide polymorphisms (SNPs) within the CCL11 gene (rs6505403, rs1860184, rs4795896, rs17735961, rs16969415 and rs17809012) were investigated in 142 IRF patients and 214 healthy controls.

RESULTS

Serum levels of eotaxin/CCL11 were higher in IRF patients than in controls (P = 0.009). Eotaxin/CCL11 drives tissue infiltration of eosinophils and MCs, which can promote fibrosis. Eosinophilic infiltration was prominent (>5 cells/hpf) in five (62.5%) cases, and abundant tryptase-positive MCs were found in all cases; notably, MCs were in a degranulating state. Immunohistochemistry showed that CCL11 was highly produced by infiltrating mononuclear cells and that its receptor CCR3 was expressed by infiltrating eosinophils, MCs, lymphocytes and fibroblasts. None of the tested CCL11 SNPs showed disease association, but the TTCCAT haplotype was significantly associated with IRF (P = 0.0005).

CONCLUSIONS

These findings suggest that the eotaxin/CCL11-CCR3 axis is active in IRF and may contribute to its pathogenesis; the TTCCAT haplotype within the CCL11 gene is significantly associated with IRF.

Anti-inflammatory effects of moxifloxacin on rat airway smooth muscle cells exposed to allergen: Inhibition of extracellular-signal-regulated kinase and nuclear factor-κB activation and of interleukin-8 and eotaxin synthesis

BACKGROUND AND OBJECTIVE

Moxifloxacin (MXF) has been shown to possess immunomodulatory properties in addition to its antimicrobial effects. We investigated the effects of MXF on cytokine secretion and signal transduction mechanisms in naive control and allergen-exposed airway smooth muscle cell (ASMC) stimulated with tumour necrosis factor (TNF)-α.

METHODS

An animal model was established. ASMC was derived from rat airway tissue and cultured in vitro, then incubated with 10 ng/mL of TNF-α. Interleukin (IL)-8 and eotaxin secretion were measured by enzyme-linked immunosorbent assay, and activation of extracellular-signal-regulated kinase (ERK)1/2 and nuclear factor (NF)-κB p65 was measured by western blotting, with or without the addition of MXF (20 µg/mL) and/or dexamethasone (DXM) (10(-6)  M).

RESULTS

Baseline IL-8 and eotaxin secretion did not differ between control and allergen-exposed cells. Stimulation with TNF-α increased IL-8 and eotaxin secretion, with increased IL-8 secretion by allergen-exposed compared with naive control ASMC, post-TNF-α stimulation (P = 0.001). Baseline phosphorylation of ERK1/2 (p-ERK1/2) and NF-κB p65 was higher in allergen-exposed than in control ASMC. TNF-α increased p-ERK1/2 and NF-κB p65 levels, with higher levels in allergen-exposed ASMC, post-TNF-α stimulation (P < 0.001). MXF and the combination of MXF with DXM suppressed the secretion of IL-8 and eotaxin, but DXM alone did not affect IL-8, post-TNF-α stimulation (P > 0.05). MXF, DXM and the combination of MXF with DXM inhibited TNF-α-stimulated p-ERK1/2 and NF-κB p65 levels by 34, 40 and 62%, and 33, 38 and 64%, respectively.

CONCLUSIONS

MXF suppressed the secretion of pro-inflammatory cytokines by allergen-exposed rat ASMC, partly by inhibiting NF-κB and ERK activation. DXM may have additional or synergistic effects with MXF.

Pathogenesis of small airways in asthma

Asthma is a lung disease characterized by inflammation and remodeling of the airways. It is now widely accepted that airway inflammation and remodeling occur not only in the central airways but also in the small airways and even in the lung parenchyma. Inflammation of the distal lung can be observed even in mild asthmatics with normal or noncompromised lung function. Moreover, the small airways and the lung parenchyma can produce many Th2 cytokines and chemokines involved in initiation and perpetuation of the inflammatory process. In addition, the distal parts of the bronchial tree have been recognized as a predominant site of airflow obstruction in many asthmatics. In fact, the inflammation at this distal site has been described as more severe when compared to the large airway inflammation, and evidence of remodeling in the lung periphery is emerging. Recognition of asthma as a disease of the entire respiratory tract has an important clinical significance, highlighting the need to also consider the distal lung as a target in any therapeutic strategy for effective treatment of this disease.

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.

Appraising the small airways in asthma

PURPOSE OF REVIEW

The small airways play an important yet poorly targeted role in asthma pathophysiology, leading to increased morbidity in asthma patients. Assessing inflammation and remodeling in these airways, determining the contribution of small airways to lung dysfunction and enhancing drug delivery to the distal regions of the lung remain challenging. The purpose of this review is to highlight recent advances in our understanding of small airways involvement in asthma.

RECENT FINDINGS

Inflammation in the small airways can be evaluated through exhaled gas measurements, most often nitric oxide. However, additional exhaled biomarkers have recently been described. Considerable infiltration of mast cells in the distal lung and extensive structural changes to the small airways have also been demonstrated. Advances have been made in the functional assessment of small airways, particularly in the measurement of small airway compliance and ventilation defects and in studies investigating the impact of small particle inhaled corticosteroid treatment on lung function.

SUMMARY

Experimental assessments of small airways inflammation, remodeling and function have provided novel insights into the importance of the distal regions of the lung in asthma pathology. Further advances in drug delivery to the small airways have the potential to improve asthma control.

The application of exhaled breath gas and exhaled breath condensate analysis in the investigation of the lower respiratory tract in veterinary medicine: A review

The analysis of biomarkers in exhaled breath (EB) and exhaled breath condensate (EBC) may allow non-invasive and repeatable assessment of respiratory health and disease in mammals. Compared to human medicine, however, research data from EB and EBC analysis in veterinary medicine are limited and more patient variables influencing concentrations of EB/EBC analytes may be present. In addition, variations in methodologies between studies may influence results. A comparison of the approaches used in veterinary research by different groups may aid in the identification of potentially reliable and repeatable biomarkers suitable for further investigation. To date, changes in acid-base status and increased concentrations of inflammatory mediators have been the main findings in studies of pulmonary disease states in animals. Whilst these biomarkers are unlikely to represent specific and sensitive diagnostic parameters, they do have potential application in monitoring disease progression and treatment response.

Eotaxin in exhaled breath condensate of allergic asthma patients with exercise-induced bronchoconstriction

BACKGROUND

Eosinophils are the key inflammatory cells in asthma, and more and more evidence suggests their crucial role in exercise-induced bronchoconstriction (EIB). Eotaxin, as the most important chemotactic factor for eosinophils, plays an important role in the pathogenesis of asthma.

OBJECTIVES

The aim of the study was to evaluate the changes in eotaxin levels in exhaled breath condensate (EBC) following intensive exercise in allergic asthmatics.

METHODS

The study was performed in a group of 27 asthmatics (17 with EIB, 13 without EIB) and 9 healthy volunteers. Changes induced by intensive exercise in the concentrations of eotaxin in EBC during the 24 h after an exercise test were assessed. The possible correlations of these measurements with the results of other tests commonly associated with eosinophilic airway inflammation were also determined.

RESULTS

In asthmatic patients with EIB, a statistically significant increase in eotaxin concentrations in EBC collected during the first 24 h after an exercise test - with maximal increase after 6 h - was revealed. A statistically significant correlation between the maximum increase in eotaxin concentrations in EBC after exercise, and an increase in either serum eosinophil cationic protein or F(ENO) 24 h after exercise in the group of asthmatics with EIB, was observed.

CONCLUSIONS

Our results confirm connections between EIB and airway eosinophilic inflammation. The increase of eotaxin in asthmatic airways, by promoting the migration and activation of eosinophils, may play an important role in upregulation and sustaining of the airway inflammation observed in EIB in asthmatic patients.