Evaluation of cytokine mRNA in induced sputum from patients with allergic rhinitis: relationship to airway hyperresponsiveness

Transcriptome analysis of sputum cells reveals two distinct molecular phenotypes of “asthma and chronic obstructive pulmonary disease overlap” in the elderly

Background

Little is known about the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD) overlap (ACO). This study examined the molecular phenotypes of ACO in the elderly.

Methods

A genome-wide investigation of gene expression in sputum cells from the elderly with asthma, ACO, or COPD was performed using gene set variation analysis (GSVA) with predefined asthma- or COPD-specific gene signatures. We then performed a subsequent cluster analysis using enrichment scores (ESs) to identify molecular clusters in the elderly with ACO. Finally, a second GSVA was conducted with curated gene signatures to gain insight into the pathogenesis of ACO associated with the identified molecular clusters.

Results

Seventy elderly individuals were enrolled (17 with asthma, 41 with ACO, and 12 with COPD). Two distinct molecular clusters of ACO were identified. Clinically, ACO cluster 1 (N = 23) was characterized by male and smoker dominance, more obstructive lung function, and higher proportions of both neutrophil and eosinophil in induced sputum compared to ACO cluster 2 (N = 18). ACO cluster 1 had molecular features similar to both asthma and COPD, with mitochondria and peroxisome dysfunction as important mechanisms in the pathogenesis of these diseases. The molecular features of ACO cluster 2 differed from those of asthma and COPD, with enhanced innate immune reactions to microorganisms identified as being important in the pathogenesis of this form of ACO.

Conclusion

Recognition of the unique biological pathways associated with the two distinct molecular phenotypes of ACO will deepen our understanding of ACO in the elderly.

Clinical features and nasal inflammation in asthma and allergic rhinitis

Asthma and allergic rhinitis (AR) are widely considered to be the most common chronic inflammatory disorders. This study was performed to investigate the clinical features, disease severity, and upper airway inflammation among patients with asthma, AR, and asthma comorbid AR. Blood and nasal lavage fluid samples were collected from patients with isolated asthma (n = 23), isolated AR (n = 22), and asthma comorbid AR (n = 22). Demographic data, symptom evaluation, and spirometry were obtained from all subjects. The levels of interleukin (IL)-4, IL-5, IL-13, IL-17, IL-25, IL-33, and S100 proteins were measured in the nasal lavage fluid. Compared with isolated asthma, patients with asthma comorbid AR showed a lower quality of life according to the asthma quality-of-life questionnaire (AQLQ) score (6.11 ± 0.47 vs. 6.45 ± 0.35, P = 0.007). Additionally, no significant difference in the levels of IL-4 (P = 0.116), IL-25 (P = 0.235), and S100A12 (P = 0.392) was observed in nasal lavage fluid among three groups. However, miniscule levels of IL-5, IL-17, IL-13, IL-33, S100A8, and S100A9 were detected in nasal lavage fluid in all three groups. Patients with asthma comorbid AR showed an increased level of systemic cytokine in plasma than that of patients with isolated AR or asthma alone. The finding from our study may help clinicians to better understand the airway inflammation among asthma patients with or without AR.

Effect of inhaled corticosteroids on microbiome and microbial correlations in asthma over a nine-month period

The effect of inhaled corticosteroids (ICS) on airway microbiome requires longitudinal research to be corroborated. Asthma patients, not undergoing ICS treatment (baseline), were enrolled and prescribed with ICS; all of these patients were followed up with regular visits at 3 months (visit 1) and 9 months (visit 2). Induced sputum was collected, fungal microbiota (mycobiome) and bacterial microbiota (bacteriome) were estimated using 16S rRNA and Internal Transcribed Spacer (ITS) sequencing. Bacterial α diversity indices were not significantly different among the baseline, visit 1 and visit 2. Visit 1 showed lower fungal evenness than the baseline, visit 2 showed lower fungal diversity and evenness than the baseline. Fungal, but not bacterial, community compositions differed significantly among the baseline, visit 1 and visit 2. The most abundant bacterial phyla and genera did not differ significantly among the baseline, visit 1 and visit 2. Compared with the baseline, visit 1 showed significantly increased frequency of fungal phylum Ascomycota and lower frequency of Basidiomycota. We found sharply decreased fungal genera Wallemia, Cladosporium, Penicillium, and Alternaria in visit 1 and visit 2 compared with the baseline, although the differences were not statistically significant. We also found the proportion of Basidiomycota was positively correlated with percentages of sputum eosinophils and neutrophils. The proportions of Saccharomyces, Wallemia, and Aplosporella were positively correlated with percentage of sputum eosinophils. Moreover, we identified distinct inter- and intra-kingdom interactions in baseline, visit 1 and visit 2. Therefore, ICS use altered the airway microbial diversity, evenness, community composition and microbial connections.

The effect of short-chain fatty acids on M2 macrophages polarization in vitro and in vivo

Alternatively activated macrophages (M2 polarization) play an important role in asthma. Short-chain fatty acids (SCFAs) possessed immune-regulatory functions, but their effects on M2 polarization of alveolar macrophages and its underlying mechanisms are still unclear. In our study, murine alveolar macrophage MH-S cell line and human monocyte-derived macrophages were used to polarize to M2 subset with interleukin-4 (IL-4) treatment. The underlying mechanisms involved were investigated using molecule inhibitors/agonists. In vivo, female C57BL/6 mice were divided into five groups: CON group, ovalbumin (OVA) asthma group, OVA+Acetate group, OVA+Butyrate group, and OVA+Propionate group. Mice were fed with or without SCFAs (Acetate, Butyrate, Propionate) in drinking water for 20 days before developing OVA-induced asthma model. In MH-S, SCFAs inhibited IL-4-incuced protein or mRNA expressions of M2-associated genes in a dose-dependent manner. G-protein-coupled receptor 43 (GPR43) agonist 4-CMTB and histone deacetylase (HDAC) inhibitor (trichostatin A, TSA), but not GPR41 agonist AR420626 could inhibit the protein or mRNA expressions M2-associated genes. 4-CMTB, but not TSA, had no synergistic role in the inhibitory effect of SCFAs on M2 polarization. In vivo study indicated Butyrate and Propionate, but not Acetate, attenuated OVA-induced M2 polarization in the lung and airway inflammation. We also found the inhibitory effect of SCFAs on M2 polarization in human-derived macrophages. Therefore, SCFAs inhibited M2 polarization in MH-S likely through GPR43 activation and/or HDAC inhibition. Butyrate and Propionate but not Acetate could inhibit M2 polarization and airway inflammation in asthma model. SCFAs also abrogated M2 polarization in human-derived macrophages.

Fungal and bacterial microbiome dysbiosis and imbalance of trans-kingdom network in asthma

Background

Fungal and bacterial microbiota play an important role in development of asthma. We aim to characterize airway microbiome (mycobiome, bacteriome) and functional genes in asthmatics and controls.

Methods

Sputum microbiome of controls, untreated asthma patients and inhaled corticosteroid (ICS) receiving patients was detected using high throughput sequencing. Metagenomic sequencing was used to examine the functional genes of microbiome.

Results

1. Mycobiome: α diversity was lower in untreated asthma group than that in controls. Mycobiome compositions differed among the three groups. Compared with controls, untreated asthma group has higher abundance of Wallemia, Mortierella and Fusarium. Compared with untreated asthma patients, ICS receiving patients has higher abundance of Fusarium and Mortierella, lower frequency of Wallemia, Alternaria and Aspergillus. 2. Bacteriome: α diversity was lower in untreated asthma group than that in controls. There are some overlaps of bacteriome compositions between controls and untreated asthma patients which were distinct from ICS receiving patients. Untreated asthma group has higher Streptococcus than controls. 3. Potential fungal and bacterial biomarkers of asthma: Trametes, Aspergillus, Streptococcus, Gemella, Neisseria, etc. 4. Correlation network: There are dense and homogenous correlations in controls but a dramatically unbalanced network in untreated asthma and ICS receiving patients, which suggested the existence of disease-specific inter-kingdom and intra-kingdom alterations. 5. Metagenomic analysis: functional pathways were associated with the status of asthma, microbiome and functional genes showed different correlations in different environment.

Conclusion

We showed mycobiome and bacteriome dysbiosis in asthma featured by alterations in biodiversity, community composition, inter-kingdom and intra-kingdom network. We also observed several functional genes associated with asthma.

Value of Exhaled Nitric Oxide and FEF25-75 in Identifying Factors Associated With Chronic Cough in Allergic Rhinitis

Purpose

Chronic cough in allergic rhinitis (AR) patients is common with multiple etiologies including cough variant asthma (CVA), non-asthmatic eosinophilic bronchitis (NAEB), gastroesophageal reflux-related cough (GERC), and upper airway cough syndrome (UACS). Practical indicators that distinguish these categories are lacking. We aimed to explore the diagnostic value of the fraction of exhaled nitric oxide (FeNO) and forced expiratory flow at 25% and 75% of pulmonary volume (FEF_25–75) in specifically identifying CVA and NAEB in these patients.

Methods

Consecutive AR patients with chronic cough were screened and underwent induced sputum, FeNO, nasal nitric oxide, spirometry, and methacholine bronchial provocation testing. All patients also completed gastroesophageal reflux disease questionnaires.

Results

Among 1,680 AR patients, 324 (19.3%) were identified with chronic cough, of whom 316 (97.5%) underwent etiology analyses. Overall, 87 (27.5%) patients had chronic cough caused by NAEB, 78 (24.7%) by CVA, 16 (5.1%) by GERC, and 81 (25.6%) by UACS. Patients with either NAEB or CVA (n = 165, in total) were further assigned to a common group designated as CVA/NAEB, because they both responded to corticosteroid therapy. Receiver operating characteristic curves of FeNO revealed obvious differences among CVA, NAEB, and CVA/NAEB (area under the curve = 0.855, 0.699, and 0.923, respectively). The cutoff values of FeNO at 43.5 and 32.5 ppb were shown to best differentiate CVA and CVA/NAEB, respectively. FEF_25–75 was significantly lower in patients with CVA than in those with other causes. A FEF_25–75 value of 74.6% showed good sensitivity and specificity for identifying patients with CVA.

Conclusions

NAEB, CVA, and UACS are common causes of chronic cough in patients with AR. FeNO can first be used to discriminate patients with CVA/NAEB, then FEF_25–75 (or combined with FeNO) can further discriminate patients with CVA from those with CVA/NAEB.

Different Biological Pathways Are Up-regulated in the Elderly With Asthma: Sputum Transcriptomic Analysis

BACKGROUND

Elderly asthma (EA) is increasing, but the pathogenesis is unclear. This study aimed to identify EA-related biological pathways by analyzing genome-wide gene expression profiles in sputum cells.

METHODS

A total of 3,156 gene probes with significantly differential expressions between EA and healthy elderly controls were used for a hierarchical clustering of genes to identify gene clusters. Gene set enrichment analysis provided biological information, with replication from Gene Expression Omnibus expression profiles.

RESULTS

Fifty-five EA patients and 10 elderly control subjects were enrolled. Two distinct gene clusters were found. Cluster 1 (n = 35) showed a lower eosinophil proportion in sputum and less severe airway obstruction compared to cluster 2 (n = 20). The replication data set also identified 2 gene clusters (clusters 1' and 2'). Among 5 gene sets significantly enriched in cluster 1 and 3 gene sets significantly enriched in cluster 2, we confirmed that 2 were significantly enriched in the replication data set (OXIDATIVE_PHOSPHORYLATION gene set in cluster 1 and EPITHELIAL MESENCHYMAL TRANSITION gene set in cluster 2').

CONCLUSIONS

The findings of 2 distinct gene clusters in EA and different biological pathways in each gene cluster suggest 2 different pathogenesis mechanisms underlying EA.

Innate immune crosstalk in asthmatic airways: Innate lymphoid cells coordinate polarization of lung macrophages

BACKGROUND

Recent studies have emphasized the role of innate lymphoid cells (ILCs) in the development of asthma. The involvement of group 2 innate lymphoid cells (ILC2s) in asthma is well studied: however, the participation of other types of ILCs in the development of asthma remains unclear.

OBJECTIVE

This study aims to understand the role of various ILCs in patients with asthma, especially their effect on macrophage polarization.

METHODS

Each subset of ILCs and macrophages in induced sputum from 51 steroid-naive patients with asthma and 18 healthy donors was analyzed by using flow cytometry. Alveolar macrophages (AM) were sorted and cocultured with each subset of ILCs to determine whether the polarization of macrophages could be regulated by ILCs.

RESULTS

In addition to ILC2s, numbers of group 1 innate lymphoid cells (ILC1s) and group 3 innate lymphoid cells (ILC3s) were increased in induced sputum from asthmatic patients when compared with those in healthy control subjects. The dominance of macrophages in induced sputum was more prominent in asthmatic patients than in healthy control subjects. A positive correlation between numbers of ILC2s and numbers of M2 macrophages and those of ILC1s/ILC3s and M1 macrophages was observed. Coculture of ILC2s with AMs induced expression of M2 macrophage-related genes, whereas coculture of ILC1s and ILC3s with AMs induced expression of M1 macrophage-related genes through cytokine secretion, as well as cell-cell contact. According to the inflammatory signature, patients with eosinophilic asthma have more ILC2s and M2 macrophages, and those with noneosinophilic asthma have an M1 macrophage-dominant profile.

CONCLUSION

A different subset of ILCs regulates macrophage polarization, contributing to developing the distinct phenotype of asthma.

Lung Microbiome Analysis in Steroid-Naїve Asthma Patients by Using Whole Sputum

Background

Although recent metagenomic approaches have characterized the distinguished microbial compositions in airways of asthmatics, these results did not reach a consensus due to the small sample size, non-standardization of specimens and medication status. We conducted a metagenomics approach by using terminal restriction fragment length polymorphism (T-RFLP) analysis of the induced whole sputum representing both the cellular and fluid phases in a relative large number of steroid naïve asthmatics.

Methods

Induced whole sputum samples obtained from 36 healthy subjects and 89 steroid-naїve asthma patients were analyzed through T-RFLP analysis.

Results

In contrast to previous reports about microbiota in the asthmatic airways, the diversity of microbial composition was not significantly different between the controls and asthma patients (p=0.937). In an analysis of similarities, the global R-value showed a statistically significant difference but a very low separation (0.148, p=0.002). The dissimilarity in the bacterial communities between groups was 28.74%, and operational taxonomic units (OTUs) contributing to this difference were as follows: OTU 789 (Lachnospiraceae), 517 (Comamonadaceae, Acetobacteraceae , and Chloroplast), 633 (Prevotella), 645 (Actinobacteria and Propionibacterium acnes), 607 (Lactobacillus buchneri, Lactobacillus otakiensis, Lactobacillus sunkii, and Rhodobacteraceae), and 661 (Acinetobacter, Pseudomonas, and Leptotrichiaceae), and they were significantly more prevalent in the sputum of asthma patients than in the sputum of the controls.

Conclusion

Before starting anti-asthmatic treatment, the microbiota in the whole sputum of patients with asthma showed a marginal difference from the microbiota in the whole sputum of the controls.

[The effectiveness of topical antihistamine monotherapy in the patients presenting with the manifestations of seasonal allergic rhinitis]

The objective of the present study was to evaluate the effectiveness and safety of monotherapy with the use of allergoferon gel composed of topical recombinant human interferon-α-2β and loratadine. A total of 105 patients at the age varying from 18 to 55 years presenting with the manifest form of seasonal allergic rhinitis were available for the examination. They were given the topical treatment in the recommended standard doses. The patients included in group 1 (n=65) were treated with allergoferon while those comprising group 3 (n=40) received mometasonefuorate (nasonex). Changes in the clinical symptoms were recorded on days 3, 7, 14, 21, and 28. The best results of the treatment were documented in the patients of group 1 on day 3 afterthe onset of therapy; this effect was attributed to the rapid beginning of the drug action that was apparent within15 minutes after the topical application of the medication. There were no significant difference between the manifestations of the symptoms on days 7 and 14 in the patients of both groups. None of the patients in group 1 refused to continue therapy up to day 28. Two patients in group 2 (5%) wished to discontinue the treatment due to side effects. It is concluded that the treatment with the allergoferon gel for the topical and external applications extends the possibilities for efficacious and safe therapy of the clinical manifestations of seasonal allergic rhinitis.

In Vivo Anti-Inflammatory Effect of H1 Antihistamines in Allergic Rhinitis: A Randomized Clinical Trial

BACKGROUND

Allergic rhinitis is characterized by a chronic inflammation of nasal mucosa and represents a risk factor for asthma occurrence. H1 antihistamines reduce the symptoms of rhinitis, but some compounds may have anti-inflammatory properties.

AIMS

We evaluated the plasma level of some cytokines in patients with persistent allergic rhinitis (PAR) and their evolution after a 4-week treatment with H1 anti-histamines, as well as the risk of asthma after 1.5 years.

STUDY DESIGN

Randomized clinical trial.

METHODS

Eighty-five patients with PAR and 30 healthy volunteers were included in the study. The patients with PAR were randomly divided into 2 groups: 41 patients treated with 5 mg/day desloratadine and 44 patients under 5 mg/day levocetirizine for 4 weeks. The clinical and biological evaluations were performed before and after treatment and included rhinitis symptoms and total symptoms score, type of sensitization, and plasmatic levels of total IgE, IL-1β, IL-6, IL-8 and TNF-α.

RESULTS

IL-8 and TNF-α were significantly increased in patients with PAR compared to healthy volunteers (5.85 vs 3.12, p<0.001 and 2.32 vs 1.06, p<0.001, respectively). Both H1 antihistamines reduce all symptoms of allergic rhinitis, including nasal congestion and the plasmatic level of IL-1β, IL-6, IL-8 and TNF-α, after 4 weeks of treatment. The reduction of cytokine levels was not influenced by patients' age, sex, duration or severity of rhinitis, or type of sensitization. Levocetirizine has a superior effect compared to desloratadine in reducing the rhinitis symptoms and cytokines' level. Twenty eight (32.9%) of the patients presented asthma symptoms after 1.5 years. The occurrence of asthma was influenced by house dust sensitization (OR-14.6; CI 95% 1.8-116.3; p=0.01), but baseline values of cytokines were not predictive factors for its appearance.

CONCLUSION

Levocetirizine and desloratadine as a prolonged therapy reduce plasmatic levels of some pro-inflammatory cytokines in patients with PAR. Levocetirizine has a better effect on decreasing the symptoms and plasmatic levels of IL-1β and IL-8. (ClinicalTrials. gov Identifier: NCT02507635).

FOUNDING

POSDRU and University of Medicine and Pharmacy, Iuliu Haţieganu, Cluj Napoca.

Rhinitis in pregnant women with asthma is associated with poorer asthma control and quality of life

OBJECTIVE

To describe the pattern and severity of rhinitis in pregnancy and the impact rhinitis has on asthma control and quality of life (QoL) in pregnant women with asthma.

METHODS

Two hundred and eighteen non-smoking pregnant women with asthma were participants in a randomised controlled trial of exhaled nitric oxide guided treatment adjustment. Rhinitis was assessed using a visual analogue scale (VAS) scored from 0 to 10 and classified as current (VAS > 2.5), moderate/severe versus mild (VAS > 6 vs <5), atopic versus non-atopic and pregnancy rhinitis. At baseline, women completed the 20-Item Sino-Nasal Outcome Test (SNOT20), asthma-specific (AQLQ-M) QoL questionnaires and the Six-Item Short-Form State Trait Anxiety Inventory (STAI-6). Asthma control was assessed using the asthma control questionnaire (ACQ). Perinatal outcomes were collected after delivery.

RESULTS

Current rhinitis was present in 142 (65%) women including 45 (20%) women who developed pregnancy rhinitis. Women with current rhinitis had higher scores for ACQ (p = 0.004), SNOT20 (p < 0.0001) and AQLQ-M (p < 0.0001) compared to women with no rhinitis. Current rhinitis was associated with increased anxiety symptoms (p = 0.002), rhinitis severity was associated with higher ACQ score (p = 0.004) and atopic rhinitis was associated with poorer lung function (p = 0.037). Rhinitis symptom severity improved significantly during gestation (p < 0.0001). There was no impact on perinatal outcomes. Improved asthma control was associated with improvement in rhinitis.

CONCLUSION

Rhinitis in pregnant women with asthma is common and associated with poorer asthma control, sino-nasal and asthma-specific QoL impairment and anxiety. In the context of active asthma management there was significant improvement in rhinitis symptoms and severity as pregnancy progressed.

Aryl hydrocarbon receptor agonists upregulate VEGF secretion from bronchial epithelial cells

Chronic airway diseases, such as asthma and chronic obstructive pulmonary disease, are characterized by airway remodeling. Vascular endothelial growth factor (VEGF) is a critical regulator of angiogenesis and vascular remodeling, important components of airway remodeling. The aryl hydrocarbon receptor (AhR) is the principle receptor for many environmental toxicants, such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), which may contribute to the pathogenesis of asthma and chronic obstructive pulmonary disease. However, the regulatory role of AhR on the expression of VEGF in bronchial epithelial cells (BECs) remains elusive. This study was conducted to determine the role of AhR in regulating bronchial epithelial VEGF expression, which might contribute to angiogenesis of airway remodeling. The plasma VEGF levels of asthmatic patients and healthy subjects were compared. By treating HBE-135, Beas-2B, and primary human BECs with AhR agonists, the mechanisms through which AhR modulated VEGF expression in human BECs were investigated. The plasma VEGF level was significantly higher in asthmatic patients than in healthy subjects. AhR agonists significantly upregulated VEGF secretion from human BECs, which promoted the migratory and tube-forming ability of human umbilical vein endothelial cells. The secretion of VEGF was increased via a canonical AhR pathway, followed by the 15-LOX/15-HETE/STAT3 pathway. C57BL/6JNarl mice treated with TCDD intratracheally also showed increased VEGF expression in BECs. This hitherto unrecognized pathway may provide a potential target for the treatment of airway remodeling in many pulmonary diseases, especially those related to environmental toxicants.

KEY MESSAGE

AhR agonists increase VEGF secretion from bronchial epithelial cells. The mechanism involves the canonical AhR pathway and 15-LOX/15-HETE/STAT3 pathway. Asthmatic patients have higher plasma VEGF level. Mice treated with intratracheal TCDD show increased VEGF expression in BECs. This novel regulatory pathway is a potential target for treating asthma and COPD.

Evaluation of vascular endothelial growth factor-A and Endostatin levels in induced sputum and relationship to bronchial hyperreactivity in patients with persistent allergic rhinitis monosensitized to house dust

BACKGROUND

Studies about the pathogenesis of bronchial hyperreactivity (BHR) in patients with persistent allergic rhinitis (PAR) and its relationship with lower airway remodeling are extremely limited.

OBJECTIVE

This study evaluated bronchial vascular remodeling via the measurement of angiogenic factor, vascular endothelial growth factor-A (VEGF-A), and anti-angiogenic factor, Endostatin, and evaluated their relationship with BHR in patients with PAR.

METHODS

The study group consisted of 30 patients with PAR monosensitized to house dust mites and 14 non-allergic healthy controls. All subjects underwent induced sputum and methacholine (M) bronchial provocation tests. VEGF-A and Endostatin levels were measured by ELISA in induced sputum supernatants.

RESULTS

The percentages of eosinophils in induced sputum were significantly increased in patients with PAR compared with healthy controls. There were no significant differences between patients with PAR and healthy controls in terms of levels of VEGF (37.9pg/ml, min-max: 5-373pg/ml vs. 24.9, min-max: 8-67pg/ml, p=0.8 respectively), Endostatin (532.5pg/ml, min-max: 150-2125pg/ml vs. 644, min-max: 223-1123pg/ml, p=0.2 respectively) and VEGF/Endostatin ratio (0.057 vs. 0.045, p=0.8 respectively). In addition, there were no significant differences between patients who are BHR positive (n=8), or negative to M (n=22) in terms of levels of VEGF, Endostatin and VEGF/Endostatin ratio and no correlations among value of PD20 to M and levels of VEGF, Endostatin and VEGF/Endostatin ratio.

CONCLUSION

We conclude that VEGF-A and Endostatin did not differ between patients with PAR and healthy controls regardless of BHR to M.

Expression levels of eosinophil granule protein mRNAs in induced sputum reflect airway hyperresponsiveness and airflow limitation

Eosinophils are regarded as the major effector cells that produce symptoms in allergic diseases. Activation of eosinophils induces extracellular release of a number of eosinophil granule proteins, including major basic protein (MBP), eosinophil cationic protein (ECP), eosinophil peroxidase (EPO), and eosinophil-derived neurotoxin. The objective of this study was to evaluate the differences and significance of the sputum eosinophil% and expression levels of eosinophilic granule protein mRNAs in allergic airway disease. Induced sputum samples were obtained from non-smokers with 25 asthma, 54 eosinophilic bronchitis, 16 allergic rhinitis, and 19 healthy control subjects. The eosinophil granule protein mRNAs were measured with real time RT-PCR. There was no correlation between the sputum eosinophil% and the mRNA level of any of eosinophil granule proteins. However, the expression levels of MBP and ECP mRNAs were higher in subjects with each of the specified allergic diseases than those in control subjects (P < 0.05). Moreover, in the subjects with allergic sensitization, the expression levels of MBP and EPO mRNAs were significantly higher in those with airway hyperresponsiveness (13 subjects) than in those without airway hyperresponsiveness (32 subjects) (P = 0.004 and 0.010, respectively). In asthma patients, the FEV1% was negatively correlated with ECP mRNA levels (r = -0.510, P = 0.022), but showed no correlation with sputum eosinophil%. In conclusion, mRNA levels of eosinophil granule proteins, rather than sputum eosinophil%, may reflect airway hyperresponsiveness and airflow limitation. In practice, consideration for the eosinophil% as well as the eosinophil granule proteins levels in induced sputum is needed.

Which biomarkers are effective for identifying Th2-driven inflammation in asthma?

Recognition of asthma as a heterogeneous disease revealed different potential molecular targets and urged the development of targeted, customized treatment modalities. Evidence was provided for different inflammatory subsets of asthma and more recently, further refined to T helper (Th)2-high and Th2-low subphenotypes with different responsiveness to standard and targeted pharmacotherapy. Given these differences in immunology and pathophysiology, proof of concept studies of novel treatment modalities for asthma should be performed in adequate, well-defined phenotypes. In this review, we describe both existing and novel biomarkers of Th2-inflammation in asthma that can be applied to classify asthma subphenotypes in clinical studies and for treatment monitoring.

Eosinophilic airway inflammation and airway hyperresponsiveness according to aeroallergen sensitization pattern in patients with lower airway symptoms

Purpose

Sensitization to specific allergens may be important in the development of allergic airway inflammation and airway hyperresponsiveness (AHR). We evaluated the effect of specific aeroallergen sensitization on eosinophilic airway inflammation and AHR.

Methods

We reviewed retrospectively the clinical data of subjects who underwent skin prick tests to aeroallergens, induced sputum analysis, and methacholine bronchial provocation tests to evaluate lower airway symptoms as well as analyzed the associations between the pattern of aeroallergen sensitization and sputum eosinophilia or AHR.

Results

Of the 1,202 subjects be enrolled, 534 (44.4%) were sensitized to at least one aeroallergen in skin tests. AHR was demonstrated in 23.5% and sputum eosinophilia in 38.8%. Sputum eosinophilia was significantly associated with sensitization to perennial allergens (OR, 1.9; 95% CI, 1.4-2.5), house dust mite (OR, 1.7; 95% CI, 1.3-2.3), dog (OR, 1.9; 95% CI, 1.1-3.3), and cat (OR, 2.1; 95% CI, 1.4-3.4). AHR was associated with sensitization to perennial allergens (OR, 2.7; 95% CI, 2.0-3.7), house dust mite (OR, 2.2; 95% CI, 1.6 3.2), Alternaria (OR, 2.3; 95% CI, 1.2-4.7), and cat (OR, 2.7; 95% CI, 1.7-4.3). Sensitization to more perennial allergens increased the risk for sputum eosinophilia and AHR. There was no relationship with individual seasonal allergens.

Conclusion

The development of airway eosinophilic inflammation and AHR in an adult Korean population was associated with sensitization to perennial allergens rather than seasonal allergens.

Expression of semaphorin 3A and neuropilin 1 in asthma

Neuropilin 1 (NP1) is a part of essential receptor complexes mediating both semaphorin3A (SEMA3A) and vascular endothelial growth factor (VEGF) which is one of important mediators involved in the pathogenesis of asthma. Therefore, it is possible that SEMA3A plays a role in the pathogenesis of asthma through attenuation of VEGF-mediated effects. In the present study, we aimed to evaluate expression levels of SEMA3A and NP1 using induced sputum of asthmatics and a murine model of asthma. Firstly, SEMA3A and NP1 expressions in induced sputum of asthmatics and SEMA3A and NP1 expression on bronchoalveolar lavage (BAL) cells and lung homogenates of asthmatic mice were determined. Then we evaluated the immunolocalization of VEGF receptor 1 (VEGFR1), VEGF receptor 2 (VEGFR2), and NP1 expressions on asthmatic mice lung tissue and their subcellular distributions using fibroblast and BEAS2B cell lines. Sputum SEMA3A and NP1 expressions were significantly higher in asthmatics than controls. Similarly, SEMA3A and NP1 expressions on BAL cells and lung homogenates were significantly elevated in asthmatic mice compared to control mice. Immunohistochemical analysis showed that VEGFR1, VEGFR2, and NP1 expressions were also uniformly increased in asthmatic mice. Our observations suggest that SEMA3A and NP1 may play important roles in the pathogenesis of asthma.

Allergic rhinitis and vascular endothelial growth factor

Vascular endothelial growth factor (VEGF) was identified in 1980s as a protein that increases vascular permeability and induces endothelial cell-specific mitosis. VEGF plays an important role in angiogenesis during the embryonic stage and in angiogenesis and in increasing vascular permeability during postnatal life, both physiologically and pathologically. Great progress has been made in studies of VEGF, mainly in the field of oncology, and VEGF-targeted therapy has been successfully used to treat patients with cancer. In research related to chronic inflammation, several reports concerning rheumatoid arthritis or retinopathy and VEGF have been published. In the lower respiratory tract, increased levels of VEGF have been detected in biological samples from patients with asthma. However, VEGF has not been studied in detail in upper-airway diseases, such as rhinosinusitis. This review article focuses on VEGF and allergic rhinitis to advance studies of VEGF in chronic inflammation of the upper respiratory tract. VEGF levels in nasal secretions and nasal lavage fluid were higher in perennial allergic rhinitis than in nonallergic rhinosinusitis, after, rather than before, the antigen provocation test. The major VEGF isoforms were confirmed to be VEGF₁₂₁ and VEGF₁₆₅ in allergic rhinitis. Expression of VEGF mRNA was higher in serous versus mucous acini. In allergic rhinitis, serous acini produced significant quantities of VEGF, which was hypersecreted after antigen provocation. VEGF seems to play an important role in the pathophysiology of allergic rhinitis. Modulation of VEGF function seems to contribute to the successful treatment of conditions with airway inflammation such as allergic rhinitis.

Expression pattern of GSTP1 and GSTA1 in the pathogenesis of asthma

Reactive oxygen species (ROS) are known aggravating factors for airway inflammation in asthma. Glutathione S-transferases (GSTs) detoxify ROS and toxic compounds in environmental exposures. However, little is known about the regulation of GST and expression of GST subtypes in asthma. The aim of this study was to evaluate how GSTs are regulated in asthma. We observed total GST activity and expression of GST subtypes in murine asthma models and GST expressions in induced sputum cells of asthmatics. Total GST activity was increased in BAL fluids of OVA-treated murine asthma model. GSTP and GSTA are highly expressed in peribronchiolar mononuclear inflammatory cells and epithelial cells in OVA-treated mice. GSTM are expressed in epithelial cells in both OVA and PBS-treated groups. GSTP1 mRNA expression was increased in the lung of OVA-treated mice compared with PBS-treated mice. GSTA1, GSTM1, and GSTT1 mRNA expressions were not different between both groups. GSTA1 mRNA expression was increased in induced sputum cells of asthmatics compared with healthy controls. GSTP1, GSTM1, and GSTT1 mRNA expressions were not different between asthmatics and healthy controls. In asthmatics, GSTP1 and GSTA1 mRNA expressions were higher in induced sputum cells of asthmatics with PC20 ≤ 4 mg/ml than those with PC20 > 4 mg/ml. GSTM1 and GSTT1 mRNA expressions were not different between two groups. These findings suggest that GSTs are upregulated in the airways of asthmatics in response to increased oxidative stress. GSTP and GSTA are thought to play an important role in protecting the airways of asthmatics compared with GSTM and GSTT.

Rhinitis patients with sputum eosinophilia show decreased lung function in the absence of airway hyperresponsiveness

Purpose

Sputum eosinophilia is observed frequently in patients with rhinitis. Sputum eosinophilia in patients with non-asthmatic allergic rhinitis has been suggested to be related to nonspecific airway hyperresponsiveness (AHR). However, the clinical significance of sputum eosinophilia in patients with non-asthmatic rhinitis without AHR has not been determined. We conducted a retrospective study examining the influence of sputum eosinophilia in patients with non-asthmatic rhinitis without AHR on pulmonary function and expression of fibrosis-related mediators.

Methods

Eighty-nine patients with moderate-to-severe perennial rhinitis without AHR were included. All underwent lung function tests (forced expiratory volume in 1 second [FEV1] and forced vital capacity [FVC]), skin tests to inhalant allergens, methacholine bronchial challenge tests, and hypertonic saline-induced sputum to determine eosinophil counts. Sputum mRNA levels for transforming growth factor-β (TGF-β), matrix metalloproteinase-9 (MMP-9), and tissue inhibitor of metalloproteinase-1 (TIMP-1) were also examined. Patients were divided into two groups according to the presence of sputum eosinophilia (≥3%, eosinophilia-positive [EP] and <3%, eosinophilia-negative [EN] groups).

Results

FEV1 was significantly lower (P=0.04) and FEV1/FVC tended to be lower (P=0.1) in the EP group than in the EN group. In sputum analyses, the MMP-9 mRNA level (P=0.005) and the ratio of MMP-9 to TIMP-1 expression (P=0.01) were significantly higher in the EP group than in the EN group. There was no significant difference in TGF-β mRNA expression between the two groups.

Conclusions

Sputum eosinophilia in patients with moderate-to-severe perennial rhinitis without AHR influenced FEV1 and the expression pattern of fibrosis-related mediators.

Evaluation of Vascular Endothelial Growth Factor A and Endostatin Levels in Induced Sputum and Relationship to Bronchial Hyperreactivity in Patients with Seasonal Allergic Rhinitis

Background

Studies about the pathogenesis of bronchial hyperreactivity (BHR) in patients with allergic rhinitis (AR) and its relationship with lower airway remodeling are extremely limited. In this study, bronchial vascular remodeling and its relationship with BHR were evaluated by measurement of vascular endothelial growth factor A (VEGF-A) and endostatin in patients with seasonal AR (SAR).

Methods

The study group consisted of 30 patients with SAR (positive skin test to grass pollens) and 14 healthy controls. Induced sputum and bronchial provocation test (BPT) to methacholine (M) were performed in season. VEGF-A and endostatin levels were measured by ELISA in induced sputum supernatant.

Results

The percentages of eosinophils in induced sputum were significantly increased in BHR+ patients (n = 10) with SAR compared with BHR– patients (n = 20) with SAR (p < 0.001). There was no correlation between eosinophils and provocative concentration of M required to produce a 20% decrease in forced expiratory volume in 1 second. The levels of VEGF-A were significantly higher in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.014 and p = 0.04). The levels of endostatin were significantly lower in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.020 and p = 0.014). The ratio of VEGF-A/endostatin was significantly higher in SAR patients with BHR than in SAR patients without BHR and healthy controls (respectively, p = 0.009 and p = 0.019).

Conclusion

In this first study comparing the VEGF-A and endostatin levels of patients with SAR in sputum supernatant, the presence of BHR was shown to be associated with the vascular component of remodeling “angiogenesis.”

The role of high-mobility group box-1 (HMGB1) in the pathogenesis of asthma

BACKGROUND

High-mobility group box 1 protein (HMGB1) belonging to endogenous danger signals prolongs eosinophil survival and acts as a chemoattractant.

OBJECTIVE

The authors evaluated the role of HMGB1 in the pathogenesis of asthma characterized by eosinophilic airway inflammation.

METHODS

Firstly, HMGB1 expressions in induced sputum obtained from human asthmatics were determined. This was followed by an evaluation of the role of HMGB1 in a murine model of asthma using anti-HMGB1 antibodies. Then the effect of HMGB1 on the receptor of advanced glycation end products (RAGE) expressions on CD11b-CD11c(+) cells isolated from a murine model of asthma were measured to elucidate the mechanisms involved.

RESULTS

Sputum HMGB1 expressions were markedly higher in asthmatics than in normal controls, and were positively correlated with sputum eosinophilia and sputum TNF-α, IL-5 and IL-13 expressions. In a murine model of asthma, HMGB1 expressions in lung tissue and HMGB1 levels in bronchoalveolar lavage fluid were significantly elevated and eosinophilic airway inflammation, non-specific airway hyperresponsiveness, and pathological changes were attenuated by blocking HMGB1 activity. Furthermore, we found that enhanced RAGE expressions on CD11b-CD11c(+) also significantly decreased when HMGB1 activity was blocked.

CONCLUSION AND CLINICAL RELEVANCE

Our findings suggest that HMGB1 plays a key role in the pathogenesis of clinical and experimental asthma characterized by eosinophilic airway inflammation.

Differences in airway inflammation according to atopic status in patients with chronic rhinitis

Background

Chronic rhinitis is a heterogeneous group of diseases that cause nasal inflammation. And the nose may be a window into the lung in the concept of "one airway one disease."

Objective

This study was conducted to evaluate differences between the different forms of chronic rhinitis in terms of lower airway inflammation.

Methods

Patients that attended the allergy clinic and presented with moderate/severe persistent rhinitis symptoms for more than 1 year were enrolled. The patients with chronic rhinitis were classified into two groups (house dust mites [HDM]-sensitive allergic rhinitis [AR] or non-allergic rhinitis [NAR]) according to the presence of atopy, and additionally according to nasal polyposis and airway hyperresponsiveness, respectively. Medical records were reviewed and the mRNA expression levels of IL-5, IFN-γ, TGF-β1, IL-17A, and IL-25 were evaluated in induced sputum samples in each group.

Results

Induced sputum samples of 53 patients were evaluated. Patients with NAR were significantly older than patients with HDM-sensitive AR (p < 0.05). Nasal polyposis was more prevalent in NAR patients than in HDM-sensitive AR patients (10.2% vs. 62.5%, p < 0.001). The expression levels of IL-17A mRNA were higher in NAR patients, regardless of the presence of airway hyperresponsiveness (p = 0.005).

Conclusion

These results suggest that patients with different forms of chronic rhinitis could have different inflammatory environments in their lower airway and NAR patients might have bronchial inflammation related to the elevated levels of IL-17A compared to HDM-sensitive AR patients.

Spirometric parameters and levels of interferon gamma and IL-5 in induced sputum from patients with allergic rhinitis or asthma

BACKGROUND

This study was designed to analyze spirometric parameters and cytokine (interferon [IFN] gamma and IL-5) levels in induced sputum from patients with asthma or allergic rhinitis (AR) and nonatopic subjects.

METHODS

Thirty-three subjects aged 18-60 years were enrolled in the present study. Eight patients had asthma without AR symptoms, 16 had AR without asthma symptoms or history, and both groups had positive skin-prick test (SPT) to aeroallergens. The nine remaining subjects were healthy nonatopic subjects with negative SPT to aeroallergens. Spirometry was performed by evaluating the forced vital capacity (FVC), forced expiratory volume in the 1st second (FEV(1)), and forced expiratory flow between 25 and 75% (FEF(25-75)) of FVC before and after bronchodilator use. Induced sputum samples were also collected for measuring cytokine (IFN-gamma and IL-5) levels by enzyme-linked immunosorbent assay.

RESULTS

Significant pre- and postbronchodilator change was observed only for FEV(1) with higher variation values in asthmatic subjects compared with patients with AR (p < 0.05) and nonatopic subjects (p < 0.01). There was no significant difference in pre- and postbronchodilator spirometric parameters among the three groups, although asthmatic patients showed lower prebronchodilator FEF(25-75) values (p = 0.065). IL-5 levels were higher in induced sputum from patients with asthma and AR compared with nonatopic subjects (p = 0.020 and p = 0.032, respectively), but IFN-gamma levels showed no significant difference between the groups.

CONCLUSION

Spirometric measurements were not able to show any occurrence of bronchial constriction in patients with AR, but predominant IL-5 levels in induced sputum from these patients reinforce the role of Th2-type immune response in lower respiratory airways that could contribute to the concept of "one airway, one disease."

Nasal disease and asthma

The nose plays a primary role within the airways, working as a filter and air-conditioner, together with other important functions. Thus, it is not surprising that nasal diseases are associated with several other comorbidities, including both upper and lower airways, such as bronchial hyperresponsiveness (BHR) and asthma. Several studies have investigated the relationship existing between the upper and the lower airways and new insights are rising. Nevertheless, some uncertainties still remain, mainly because nasal disorders are quite heterogeneous, overlapping (i.e. rhinitis-rhinosinusitis-sinusitis, acute or chronic, allergic or non-allergic) and difficult to diagnose, so that, frequently, many studies don’t differentiate between the various conditions. For this reason, the purpose of this review is to systematically analyze present epidemiological, pathophysiological and clinical data on the relationship between nasal diseases and asthma, splitting up three main conditions: allergic rhinitis, chronic rhinosinusitis and nasal polyposis.

Clinical characteristics and long-term outcomes related to sputum eosinophilia in Korean asthmatics

BACKGROUND

Bronchial asthma is usually associated with high sputum eosinophil levels. However, recent reports have suggested the importance of noneosinophilic asthma (NEA) as a distinct phenotype of asthma.

OBJECTIVE

The aim of this study was to evaluate clinical significance of sputum eosinophilia and long-term treatment outcomes related to sputum eosinophilia in Korean asthmatics.

METHODS

A total of 201 steroid-naive asthmatics who had undergone induced sputum analysis at baseline were selected from the Cohort for Reality and Evolution of Adult Asthma study population. Clinical evaluation, spirometry, a skin-prick test, a methacholine bronchial provocation test, and sputum eosinophil analysis were performed initially, and patients received the treatment recommended by the Global Initiative for Asthma. Lung function was evaluated every 6 months, and 53 patients completed 24 months of regular follow-up visits. Sputum eosinophilia was defined as a sputum eosinophil count of >3%.

RESULTS

Of the 201 steroid-naive asthmatics, 97 patients had NEA and 104 had eosinophilic asthma (EA). Only 52% of steroid-naive asthmatic subjects had elevated baseline sputum eosinophil levels. A higher percentage of sputum eosinophils was associated with a lower PC20 (r = -0.193; p = 0.009, Spearman correlation), but not with forced expiratory volume in one second (FEV1) (r = 0.045; p = 0.525). During the 24-month study period, the percentage change of FEV1 was significantly lower in the NEA group than in the EA group at 6, 12, 18, and 24 months (p < 0.05). The NEA group, unlike the EA group, showed no significant improvement in FEV1 at 6, 12, 18, or 24 months (p > 0.05).

CONCLUSION

A higher sputum eosinophil percentage was correlated with a higher airway hyperresponsiveness. Compared with EA patients, NEA patients had poor treatment outcomes in the 2-year follow-up of a Korean asthma cohort population.

Rhinosinusitis and asthma: the missing link

PURPOSE OF REVIEW

Disease of the nose and sinuses is the most common comorbidity associated with asthma. Rhinitis, sinusitis and asthma may represent part of one disease process with manifestations at different sites. The purpose of this review is to highlight significant new findings on the epidemiological and pathophysiological link between the upper and lower airway. Finally, we will review recent data assessing the impact of treating sinonasal disease on both the development of asthma and asthma control.

RECENT FINDINGS

Studies illustrate that rhinitis is very common in asthma, and associated with worse asthma control. Rhinitis typically precedes the development of asthma. Even in patients with rhinitis without asthma, there is evidence of subclinical change in the lower airways as measured by physiological changes and the presence of inflammatory mediators. There is much interest on the impact of treating allergic rhinitis on the development of asthma.

SUMMARY

Rhinitis, sinusitis and asthma are likely part of one disease process. Treatment of established rhinitis may have some impact on measures of airway obstruction, but an effect on lower airway inflammation is yet to be established. Prospective studies are required to determine whether treatment of rhinitis can prevent the development of asthma, or decrease airway inflammation to improve asthma outcomes in those with established asthma or both.

Airway angiogenesis in patients with rhinitis and controlled asthma

BACKGROUND

Airway angiogenesis may be an important part of structural remodelling in the pathogenesis of asthma. The development of asthma is frequently preceded by rhinitis.

OBJECTIVE

We sought to determine whether the levels of angiogenesis-related factors are elevated in airways of patients with rhinitis or controlled asthma.

METHODS

We analysed the induced sputum of 18 rhinitis patients, 16 asthmatic patients, and 15 healthy controls. The concentrations of angiogenin, vascular endothelial growth factor (VEGF), IL-8, fibroblast growth factor (bFGF), and TNF-alpha were measured by cytometric bead arrays.

RESULTS

We found significantly increased angiogenin and VEGF concentrations in the induced sputum supernatant of both rhinitis and asthma patients compared with that of the healthy control group (P< or =0.0005). With the exception of TNF-alpha, there was no difference in the other angiogenic factors; TNF-alpha levels were higher in the rhinitis group than in the control group (P=0.02).

CONCLUSION

These in vivo results suggest increased airway angiogenesis in patients with rhinitis without asthma as well as in corticosteroid-treated and well-controlled asthma patients.