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

Biomonitoring Environmental Exposure in Syrian Refugees in Lebanon

Over one million Syrian refugees have been residing in substandard living conditions in Lebanon for the past decade. Non-invasive biomonitoring of fractional exhaled nitric oxide (FeNO) as a pulmonary inflammation biomarker was conducted following and preceding indoor environmental assessments (which revealed elevated mould counts in informal tented settlements and non-residential shelters) to further evaluate effects of environmental exposure to indoor contaminants. Results of biomonitoring (n = 57) provided some insight regarding existing respiratory conditions and the possible implementation of minimally invasive methods to establish susceptibility profiles in Syrian refugees amid limited access to healthcare. The clinical interpretation of FeNO results suggested possible persistent exposure to allergens in addition to significant type 2 inflammation in some subjects. These findings warrant the need to expand this study, investigate other biomarkers, and attempt to correlate findings with environmental conditions to evaluate if a dose-response relationship exists.

Evaluation of cytokines in exhaled breath condensate in an occupationally exposed population to pneumotoxic pollutants

The quarrying is considered a precarious occupation with high toxicity, is an informal economic activity that employs low technology, limited protection, and poses a risk to workers and their families. In quarrying, silica dust is generated and there is also occupational exposure to significant mixtures of pneumotoxic pollutants, including mineral dust (crystalline silica, carbon or cement, polycyclic aromatic hydrocarbons (PAHs), solvents, and others, which are aggravated by the lack of use of protective equipment, causing irreversible damage to the worker's respiratory health. Thus, the objective of this work focused on the evaluation of the respiratory health of artisan stonemasons in San Luis Potosí, Mexico through the study of exhaled breath condensate (EBC) (pH, pro-inflammatory cytokines) as well as the study of the exposure to pollutants present in the work area (PAHs, toluene, and 2.5 µm particulate matter) through biomarkers of exposure (hippuric acid and hydroxylated metabolites of PAHs). The results show the presence of crystalline SiO₂ in 100% of the samples analyzed; the PM_2.5 concentrations were 5 to 10 times the permitted levels. Regarding exposure to PAHs, all the stonemasons presented urine concentrations of at least 5 of the OH-PAHs evaluated; 9-OH-FLU occurred at higher concentrations of 171.2 (122.7-279.4) µg L^-1; hippuric acid, which was present in 100% of the workers evaluated in concentrations of 283.4 (27.72-1119) mg L^-1, 100% of which were above the values established for occupational scenarios. The pH values obtained for the EBC samples were presented at an average of 7.07 (6.33-7.66). Pro-inflammatory cytokines were present in 86.1% of the study population. The cytokine that was found in higher concentrations was IL-2, with a mean of 178.01 pg mL^-1 and 3124.01 pg mL^-1 for the pH < 7 and pH > 7 groups, respectively. Some correlations between the cytokines and the exposure biomarkers were presented. Stonemasons are highly exposed to pneumotoxic pollutants and markers of inflammation at the pulmonary level; in addition, a high risk of developing silicosis. Quarrying should be addressed as a carcinogenic activity, which would imply the design of monitoring and control strategies for these pollutants that our country currently lacks, particularly in precarious occupations. It is necessary to develop strategies to protect the health of precarious workers.

Abi1 mediates airway smooth muscle cell proliferation and airway remodeling via Jak2/STAT3 signaling

Asthma is a complex pulmonary disorder with multiple pathological mechanisms. A key pathological feature of chronic asthma is airway remodeling, which is largely attributed to airway smooth muscle (ASM) hyperplasia that contributes to thickening of the airway wall and further drives asthma pathology. The cellular processes that mediate ASM cell proliferation are not completely elucidated. Using multiple approaches, we demonstrate that the adapter protein Abi1 (Abelson interactor 1) is upregulated in ∼50% of ASM cell cultures derived from patients with asthma. Loss-of-function studies demonstrate that Abi1 regulates the activation of Jak2 (Janus kinase 2) and STAT3 (signal transducers and activators of transcription 3) as well as the proliferation of both nonasthmatic and asthmatic human ASM cell cultures. These findings identify Abi1 as a molecular switch that activates Jak2 kinase and STAT3 in ASM cells and demonstrate that a dysfunctional Abi1-associated pathway contributes to the progression of asthma.

LncRNA RP5-857K21.7 inhibits PDGF-BB-induced proliferation and migration of airway smooth muscle cells through the miR-508-3p/PI3K/AKT/mTOR axis

The continuous increase in the prevalence of asthma poses a threat to human health. Despites numerous researches, the understanding of asthma development still remain elusive, hindering the development of effective treatment. Here, we explored the role of lncRNA RP5-857K21.7 (RP5-857K21.7) in the development of asthma and its potential molecular mechanism of regulation. Airway smooth muscle cells (ASMCs) were isolated and cultured after which some of the cells were induced with PDGF-BB to build an asthma cell model, and then, qRT-PCR analysis was used to measure the expression level of RP5-857K21.7 in the cell model. Result shows that the RP5-857K21.7 is significantly downregulated in PDGF-BB-induced ASMCs cells. Through CCK-8, transwell, and flow cytometry assay, we examined the functional impact of RP5-857K21.7 on the proliferation, migration, and apoptosis of the ASMCs, respectively, and found that the overexpression of RP5-857K21.7 markedly inhibit PDGF-BB-induced ASMCs cell proliferation, migration and induce apoptosis. Bioinformatics analysis predicted that the RP5-857K21.7 could sponge miR-508-3p and result was validated through a dual-luciferase reporter assay, biotinylated RNA pull-down assay, and RIP-qRT-PCR analysis. Mechanistically, RP5-857K21.7 regulates the PI3K/AKT/mTOR pathway by endogenously sponging miR-508-3p to inhibit PDGF-BB-induced ASMCs cell proliferation, migration and induce apoptosis. The current research suggests that the RP5-857K21.7 and its associated molecular pathway (miR-508-3p/PI3K/AKT/mTOR axis) might be a useful therapeutic target for the treatment of asthma disease.

Role of Platelet-Derived Growth Factor (PDGF) in Asthma as an Immunoregulatory Factor Mediating Airway Remodeling and Possible Pharmacological Target

Asthma is a chronic and heterogenic disease of the respiratory system, one of the most common lung diseases worldwide. The underlying pathologies, which are chronic inflammatory process and airway remodeling (AR), are mediated by numerous cells and cytokines. Particularly interesting in this field is the platelet-derived growth factor (PDGF), one of the members of the human growth factor family. In this article, the authors analyze the available data on the role of PDGF in asthma in experimental models and in human research. PDGF is expressed in airway by various cells contributing to asthma pathogenesis—mast cells, eosinophils, and airway epithelial cells. Research confirms the thesis that this factor is also secreted by these cells in the course of asthma. The main effects of PDGF on bronchi are the proliferation of airway smooth muscle (ASM) cells, migration of ASM cells into the epithelium and enhanced collagen synthesis by lung fibroblasts. The importance of AR in asthma is well recognized and new therapies should also aim to manage it, possibly targeting PDGFRs. Further studies on new and already existing drugs, mediating the PDGF signaling and related to asthma are necessary. Several promising drugs from the tyrosine kinase inhibitors group, including nilotinib, imatinib masitinib, and sunitinib, are currently being clinically tested and other molecules are likely to emerge in this field.

Inhibitors of nitric oxide synthase can reduce extracellular traps from neutrophils in asthmatic children in vitro

AIM

This study aimed to explore the link between neutrophil extracellular traps (NETs) and childhood asthma, to investigate the ability of nitric oxide (NO) to induce NETs in asthmatic children and find inhibitors to reduce NETs in the NO synthesis pathway.

METHODS

A total of 49 children with mild persistent asthma were included in the study and 20 healthy children's blood samples were collected as healthy controls. Children with asthma were divided into symptomatic and asymptomatic groups according to the presence or absence of symptoms on the day of blood collection. Neutrophils in peripheral blood were isolated and plasma was preserved. NO donor (sodium nitroferricyanide(III) dehydrate [SNP]) could provide NO and proved by a fluorescent probe. A PicoGreen Kit was used to detect the NETs quantificationally. Fluorescence microscopy prepared to observe the main structures of NETs. We measured NETs components (extracellular free double-stranded DNA [dsDNA]) in healthy, symptomatic and asymptomatic groups' plasma samples, and we compared the ability of SNP with phosphate-buffered saline, lipopolysaccharides (LPS), and phorbol 12-myristate 13-acetate (PMA) to induce NETs. NO synthase (NOS) inhibitors were added to see the impact on NETs formation.

RESULTS

Plasma was obtained from all blood samples of 69 children. The neutrophils of 40 asthmatic and 20 healthy children were successfully obtained, the recovery rate was over 95%, and the cell activity was over 80%. There was higher extracellular free dsDNA in the plasma of symptomatic group (n = 27) than asymptomatic group (n = 22) and healthy group (n = 20; P < .05). Studies on neutrophils from 40 children with asthma found that NO can be produced by adding SNP, PMA, and LPS. SNP could induce NETs with dose- and time-dependent. PMA (160 nM) had the strongest ability to induce NETs, LPS (200 ng/mL) followed, SNP (200 µM) was the weakest (P < .05), and the amount of NETs in the asthma group was significantly higher than that in the healthy group (P < .05). NOS inhibitors had the same blocking capacity for PMA- and LPS-induced NETs (P > .05), while NG-nitro- l-arginine methyl ester (500 µM) had the strongest inhibitory effect on SNP induction with time-dependent (P < .05). Inducible NOS was found in the NETs structure.

CONCLUSION

Children with asthma had higher levels of NETs in peripheral blood, especially when they had asthma symptoms. We verified the ability of NO to induce NETs, and found neutrophils from asthmatic children can produce more NETs in vitro. NOS inhibitors blocked this process may provide new therapeutic targets for childhood asthma.

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

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

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

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

The common γ-chain cytokine IL-7 promotes immunopathogenesis during fungal asthma

Asthmatics sensitized to fungi are reported to have more severe asthma, yet the immunopathogenic pathways contributing to this severity have not been identified. In a pilot assessment of human asthmatics, those subjects sensitized to fungi demonstrated elevated levels of the common γ-chain cytokine IL-7 in lung lavage fluid, which negatively correlated with the lung function measurement PC20. Subsequently, we show that IL-7 administration during experimental fungal asthma worsened lung function and increased the levels of type 2 cytokines (IL-4, IL-5, IL-13), proallergic chemokines (CCL17, CCL22) and proinflammatory cytokines (IL-1α, IL-1β). Intriguingly, IL-7 administration also increased IL-22, which we have previously reported to drive immunopathogenic responses in experimental fungal asthma. Employing IL22CreR26ReYFP reporter mice, we identified γδ T cells, iNKT cells, CD4 T cells and ILC3s as sources of IL-22 during fungal asthma; however, only iNKT cells were significantly increased after IL-7 administration. IL-7-induced immunopathogenesis required both type 2 and IL-22 responses. Blockade of IL-7Rα in vivo resulted in attenuated IL-22 production, lower CCL22 levels, decreased iNKT cell, CD4 T-cell and eosinophil recruitment, yet paradoxically increased dynamic lung resistance. Collectively, these results suggest a complex role for IL-7 signaling in allergic fungal asthma.

Determining the presence of asthma-related molecules and salivary contamination in exhaled breath condensate

Background

Researchers investigating lung diseases, such as asthma, have questioned whether certain compounds previously reported in exhaled breath condensate (EBC) originate from saliva contamination. Moreover, despite its increasing use in ‘omics profiling studies, the constituents of EBC remain largely uncharacterized. The present study aims to define the usefulness of EBC in investigating lung disease by comparing EBC, saliva, and saliva-contaminated EBC using targeted and untargeted mass spectrometry and the potential of metabolite loss from adsorption to EBC sample collection tubes.

Methods

Liquid chromatography mass spectrometry (LC-MS) was used to analyze samples from 133 individuals from three different cohorts. Levels of amino acids and eicosanoids, two classes of molecules previously reported in EBC and saliva, were measured using targeted LC-MS. Cohort 1 was used to examine contamination of EBC by saliva. Samples from Cohort 1 consisted of clean EBC, saliva-contaminated EBC, and clean saliva from 13 healthy volunteers; samples were analyzed using untargeted LC-MS. Cohort 2 was used to compare eicosanoid levels from matched EBC and saliva collected from 107 asthmatic subjects. Samples were analyzed using both targeted and untargeted LC-MS. Cohort 3 samples consisted of clean-EBC collected from 13 subjects, including smokers and non-smokers, and were used to independently confirm findings; samples were analyzed using targeted LC-MS, untargeted LC-MS, and proteomics. In addition to human samples, an in-house developed nebulizing system was used to determine the potential for EBC samples to be contaminated by saliva.

Results

Out of the 400 metabolites detected in both EBC and saliva, 77 were specific to EBC; however, EBC samples were concentrated 20-fold to achieve this level of sensitivity. Amino acid concentrations ranged from 196 pg/mL – 4 μg/mL (clean EBC), 1.98 ng/mL – 6 μg/mL (saliva-contaminated EBC), and 13.84 ng/mL – 1256 mg/mL (saliva). Eicosanoid concentration ranges were an order of magnitude lower; 10 pg/mL – 76.5 ng/mL (clean EBC), 10 pg/mL – 898 ng/mL (saliva-contaminated EBC), and 2.54 ng/mL – 272.9 mg/mL (saliva). Although the sample size of the replication cohort (Cohort 3) did not allow for statistical comparisons, two proteins and 19 eicosanoids were detected in smoker vs. non-smoker clean-EBC.

Conclusions

We conclude that metabolites are present and detectable in EBC using LC-MS; however, a large starting volume of sample is required.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-017-0538-5) contains supplementary material, which is available to authorized users.

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

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

Can mean platelet volume be used as a biomarker for asthma?

Introduction

Platelets play important roles in airway inflammation and are activated in inflammatory lung diseases, including asthma.

Aim

We evaluated the mean platelet volume (MPV), used as a marker of platelet activation, in asthmatic patients during asymptomatic periods and exacerbations compared to healthy controls to determine whether MPV can be used as an indicator of inflammation.

Material and methods

Our patient group consisted of 95 children with exacerbation of asthma who were admitted to our allergy clinic. The control group consisted of 100 healthy children matched for age, gender, and ethnicity. Mean platelet volume values of the patient group obtained during exacerbation of asthma were compared to those of the same group during the asymptomatic period and with the control group. We investigated factors that can affect the MPV values of asthma patients, including infection, atopy, immunotherapy treatment, and severity of asthma exacerbation.

Results

The patient group consisted of 50 (52.6%) boys and 45 (47.4%) girls with a mean age of 125 ±38 months old. Mean MPV values in the exacerbation period, the healthy period, and in the control group were 8.1 ±0.8 fl, 8.1 ±1.06 fl, and 8.2 ±0.9 fl, respectively; there were no significant differences between groups (p > 0.05). The severity of asthma, severity of asthma exacerbation, immunotherapy, coinfection, eosinophil count, and IgE level also had no effect on MPV (p > 0.05).

Conclusions

Although platelets play a role in the pathophysiology of asthma, MPV measurement is insufficient to detect inflammation through platelets.

PDGF-BB induces PRMT1 expression through ERK1/2 dependent STAT1 activation and regulates remodeling in primary human lung fibroblasts

Tissue remodeling of sub-epithelial mesenchymal cells is a major pathology occurring in chronic obstructive pulmonary disease (COPD) and asthma. Fibroblasts, as a major source of interstitial connective tissue extracellular matrix, contribute to the fibrotic and inflammatory changes in these airways diseases. Previously, we described that protein arginine methyltransferase-1 (PRMT1) participates in airway remodeling in a rat model of pulmonary inflammation. In this study we investigated the mechanism by which PDGF-BB regulates PRMT1 in primary lung fibroblasts, isolated from human lung biopsies. Fibroblasts were stimulated with PDGF-BB for up-to 48h and the regulatory and activation of signaling pathways controlling PRMT1 expression were determined. PRMT1 was localized by immuno-histochemistry in human lung tissue sections and by immunofluorescence in isolated fibroblasts. PRMT1 activity was suppressed by the pan-PRMT inhibitor AMI1. ERK1/2 mitogen activated protein kinase (MAPK) was blocked by PD98059, p38 MAPK by SB203580, and STAT1 by small interference (si) RNA treatment. The results showed that PDGF-BB significantly increased PRMT1 expression after 1h lasting over 48h, through ERK1/2 MAPK and STAT1 signaling. The inhibition of ERK1/2 MAPK or of PRMT1 activity decreased PDGF-BB induced fibroblast proliferation, COX2 production, collagen-1A1 secretion, and fibronectin production. These findings suggest that PRMT1 is a central regulator of tissue remodeling and that the signaling sequence controlling its expression in primary human lung fibroblast is PDGF-ERK-STAT1. Therefore, PRMT1 presents a novel therapeutic and diagnostic target for the control of airway wall remodeling in chronic lung diseases.