Blood eosinophil count and airway epithelial transcriptome relationships in COPD versus asthma

Towards precision medicine in COPD: Targeting type 2 cytokines and alarmins

Chronic obstructive pulmonary disease (COPD) is a main global epidemic increasing as population age and affecting approximately 10% of subjects over 45 years. COPD is a heterogeneous inflammatory disease with several endo-phenotypes and clinical presentations. Although neutrophilic inflammation is canonically considered a hallmark of COPD, eosinophilic inflammation can also be present in a subgroup of patients. Several other immune cells and cytokines play a key role in orchestrating and perpetuating the inflammatory pathways in COPD, making them attractive targets for treating this disorder. Recent studies have started to evaluate the possible role of type 2 (T2) inflammation and epithelial-derived alarmins (TSLP and IL-33) in COPD. Two phase III randomized clinical trials (RCTs) showed a modest reduction in exacerbations in COPD patients with eosinophilic phenotype treated with mepolizumab (anti-IL-5) or benralizumab (anti-IL-5Rα). A phase III RCT showed a 30% reduction in exacerbations in COPD patients with ≥ 300 eosinophils/μL treated with dupilumab (anti-IL-4Rα). These results suggest that blocking a single cytokine (e.g., IL-5) or its main target (i.e., IL-5Rα) is less promising than blocking a wider spectrum of cytokines (i.e., IL-4 and IL-13) in COPD. TSLP and IL-33 are upstream regulators of T2-high and T2-low immune responses in airway inflammation. Several ongoing RCTs are evaluating the efficacy and safety of anti-TSLP (tezepelumab), anti-IL-33 (itepekimab, tozorakimab), and anti-ST2 (astegolimab) in patients with COPD, who experience exacerbations. In conclusion, targeting T2 inflammation or epithelial-derived alarmins might represent a step forward in precision medicine for the treatment of a subset of COPD.

The functional role of CST1 and CCL26 in asthma development

BACKGROUND

Asthma is the most common chronic disease in children with an increasing prevalence. Its development is caused by genetic and environmental factors and allergic sensitization is a known trigger. Dog allergens affect up to 30% of all children and dog dander-sensitized children show increased expression of cystatin-1 (CST1) and eotaxin-3 (CCL26) in nasal epithelium. The aim of our study was to investigate the functional mechanism of CST1 and CCL26 in the alveolar basal epithelial cell line A549.

METHODS

A549 cells were transfected with individual overexpression vectors for CST1 and CCL26 and RNA sequencing was performed to examine the transcriptomics. edgeR was used to identify differentially expressed genes (= DEG, |log2 FC | ≥ 2, FDR < 0.01). The protein expression levels of A549 cells overexpressing CST1 and CCL26 were analyzed using the Target 96 inflammation panel from OLINK (antibody-mediated proximity extension-based assay; OLINK Proteomics). Differentially expressed proteins were considered with a |log2 FC| ≥ 1, p < .05.

RESULTS

The overexpression of CST1 resulted in a total of 27 DEG (1 upregulated and 26 downregulated) and the overexpression of CCL26 in a total of 137 DEG (0 upregulated and 137 downregulated). The gene ontology enrichment analysis showed a significant downregulation of type I and III interferon signaling pathway genes as well as interferon-stimulated genes. At the protein level, overexpression of CST1 induced a significantly increased expression of CCL3, whereas CCL26 overexpression led to increased expression of HGF, and a decrease of CXCL11, CCL20, CCL3 and CXCL10.

CONCLUSION

Our results indicate that an overexpression of CST1 and CCL26 cause a downregulation of interferon related genes and inflammatory proteins. It might cause a higher disease susceptibility, mainly for allergic asthma, as CCL26 is an agonist for CCR-3-carrying cells, such as eosinophils and Th2 lymphocytes, mostly active in allergic asthma.

How inhaled corticosteroids target inflammation in COPD

Inhaled corticosteroids (ICS) are the most commonly used anti-inflammatory drugs for the treatment of COPD. COPD has been previously described as a "corticosteroid-resistant" condition, but current clinical trial evidence shows that selected COPD patients, namely those with increased exacerbation risk plus higher blood eosinophil count (BEC), can benefit from ICS treatment. This review describes the components of inflammation modulated by ICS in COPD and the reasons for the variation in response to ICS between individuals. There are corticosteroid-insensitive inflammatory pathways in COPD, such as bacteria-induced macrophage interleukin-8 production and resultant neutrophil recruitment, but also corticosteroid-sensitive pathways including the reduction of type 2 markers and mast cell numbers. The review also describes the mechanisms whereby ICS can skew the lung microbiome, with reduced diversity and increased relative abundance, towards an excess of proteobacteria. BEC is a biomarker used to enable the selective use of ICS in COPD, but the clinical outcome in an individual is decided by a complex interacting network involving the microbiome and airway inflammation.

Does Chronic Obstructive Pulmonary Disease Originate from Different Cell Types?

The onset of chronic obstructive pulmonary disease (COPD) is heterogeneous, and current approaches to define distinct disease phenotypes are lacking. In addition to clinical methodologies, subtyping COPD has also been challenged by the reliance on human lung samples from late-stage diseases. Different COPD phenotypes may be initiated from the susceptibility of different cell types to cigarette smoke, environmental pollution, and infections at early stages that ultimately converge at later stages in airway remodeling and destruction of the alveoli when the disease is diagnosed. This perspective provides discussion points on how studies to date define different cell types of the lung that can initiate COPD pathogenesis, focusing on the susceptibility of macrophages, T and B cells, mast cells, dendritic cells, endothelial cells, and airway epithelial cells. Additional cell types, including fibroblasts, smooth muscle cells, neuronal cells, and other rare cell types not covered here, may also play a role in orchestrating COPD. Here, we discuss current knowledge gaps, such as which cell types drive distinct disease phenotypes and/or stages of the disease and which cells are primarily affected by the genetic variants identified by whole genome-wide association studies. Applying new technologies that interrogate the functional role of a specific cell type or a combination of cell types as well as single-cell transcriptomics and proteomic approaches are creating new opportunities to understand and clarify the pathophysiology and thereby the clinical heterogeneity of COPD.

Exhaled nitric oxide, eosinophils and current smoking in COPD patients

High FENO can occur despite low blood eosinophil counts in ex-smokers, while a minority of current smokers have elevated FENO that is not related to eosinophil counts. FENO levels may be related to noneosinophilic mechanisms in a subgroup of COPD. https://bit.ly/3PSWvM2.

Environmental pollutants increase the risks of acute exacerbation in patients with chronic airway disease

Objective

Respiratory infections are a common cause of acute exacerbations in patients with chronic airway disease, however, environmental factors such as air pollution can also contribute to these exacerbations. The study aimed to determine the correlation between pollutant levels and exacerbation risks in areas exposed to environmental pollution sources.

Methods

From 2015 to 2016, a total of 788 patients with chronic airway diseases were enrolled in a study. Their medical records, including hospital visits due to acute exacerbations of varying severity were analyzed. Additionally, data on daily pollutant levels from the Air Quality Monitoring Network from 2014 to 2016 was also collected and analyzed.

Results

Patients with chronic airway disease and poor lung function (FEV1 < 50% or obstructive ventilatory defect) have a higher risk of severe acute exacerbations and are more likely to experience more than two severe acute exacerbations within a year. The study found that in areas exposed to environmental pollution sources, there is a significant correlation between NO2, O3, and humidity with the main causes of severe acute exacerbation. When the levels of NO2 were higher than 16.65 ppb, O3 higher than 35.65 ppb, or humidity higher than 76.95%, the risk of severe acute exacerbation in patients with chronic airway disease increased.

Conclusion

Acute exacerbations of chronic airway disease can be triggered by both the underlying disease state and the presence of air pollution. Computer simulations and early warning systems should be developed to predict acute exacerbations of chronic airway disease based on dynamic changes in air pollution.

Targeting Type 2 Inflammation and Epithelial Alarmins in Chronic Obstructive Pulmonary Disease: A Biologics Outlook

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, progressive inflammatory airway disease associated with a significant impact on patients' lives, including morbidity and mortality, and significant healthcare costs. Current pharmacologic strategies, including first- and second-line therapies such as long-acting β2-agonists, long-acting muscarinic antagonists, inhaled corticosteroids, phosphodiesterase-4 inhibitors, and macrolides, provide relief to patients with COPD. However, many patients remain symptomatic, with persistent symptoms and/or acute exacerbations and progressive lung function loss. Although neutrophilic inflammation is the most common type of inflammation in COPD, 20-40% of patients with COPD exhibit type 2 inflammation, with roles for CD4+ (cluster of differentiation 4) T-helper cell type 1 cells, type 2 innate lymphoid cells, eosinophils, and alternatively activated macrophages. On the basis of the current limitations of available therapies, a significant unmet need exists in COPD management, including the need for targeted therapies to address the underlying pathophysiology leading to disease progression, such as type 2 inflammation, as well as biomarkers to help select the patients who would most benefit from the new therapies. Significant progress is being made, with evolving understanding of the pathobiology of COPD leading to novel therapeutic targets including epithelial alarmins. In this review, we describe the current therapeutic landscape in COPD, discuss unmet treatment needs, review the current knowledge of type 2 inflammation and epithelial alarmins in COPD, explore potential biomarkers of type 2 inflammation in COPD, and finally provide a rationale for incorporating therapies targeting type 2 inflammation and epithelial alarmins in COPD. Video Abstract available online at www.atsjournals.org.

Epithelial CST1 Promotes Airway Eosinophilic Inflammation in Asthma via the AKT Signaling Pathway

PURPOSE

Epithelial cystatin SN (CST1), a type 2 cysteine protease inhibitor, was significantly upregulated in asthma. In this study, we aimed to investigate the potential role and mechanism of CST1 in eosinophilic inflammation in asthma.

METHODS

Bioinformatics analysis on Gene Expression Omnibus datasets were used to explore the expression of CST1 in asthma. Sputum samples were collected from 76 asthmatics and 22 control subjects. CST1 mRNA and protein expression in the induced sputum were measured by real-time polymerase chain reaction, enzyme-linked immunosorbent assay, and western blotting. The possible function of CST1 was explored in ovalbumin (OVA)-induced eosinophilic asthma. Transcriptome sequencing (RNA-seq) was used to predict the possible regulated mechanism of CST1 in bronchial epithelial cells. Overexpression or knockdown of CST1 was further used to verify potential mechanisms in bronchial epithelial cells.

RESULTS

CST1 expression was significantly increased in the epithelial cells and induced sputum of asthma. Increased CST1 was significantly associated with eosinophilic indicators and T helper cytokines. CST1 aggravated airway eosinophilic inflammation in the OVA-induced asthma model. In addition, overexpression of CST1 significantly enhanced the phosphorylation of AKT and the expression of serpin peptidase inhibitor, clade B, member 2 (SERPINB2), while knockdown using anti-CST1 siRNA reversed the trend. Furthermore, AKT had a positive effect on SERPINB2 expression.

CONCLUSIONS

Increased sputum CST1 may play a key role in the pathogenesis of asthma through involvement in eosinophilic and type 2 inflammation through activation of the AKT signaling pathway, further promoting SERPINB2 expression. Therefore, targeting CST1 might be of therapeutic value in treating asthma with severe and eosinophilic phenotypes.

Cystatin SN in type 2 inflammatory airway diseases

Cystatin SN, encoded by CST1, belongs to the type 2 (T2) cystatin protein superfamily. In the past decade, several publications have highlighted the association between cystatin SN and inflammatory airway diseases including chronic rhinosinusitis, rhinitis, asthma, chronic obstructive pulmonary disease, and chronic hypersensitivity pneumonitis. It is, therefore, crucial to understand the role of cystatin SN in the wider context of T2 inflammatory diseases. Here, we review the expression of cystatin SN in airway-related diseases with different endotypes. We also emphasize the physiological and pathological roles of cystatin SN. Physiologically, cystatin SN protects host tissues from destructive proteolysis by cysteine proteases present in the external environment or produced via internal dysregulated expression. Pathologically, the secretion of cystatin SN from airway epithelial cells initiates and amplifies T2 immunity and subsequently leads to disease. We further discuss the development of cystatin SN as a T2 immunity marker that can be monitored noninvasively and assist in airway disease management. The discovery, biology, and inhibition capability are also introduced to better understand the role of cystatin SN in airway diseases.

IL1RAP expression and the enrichment of IL-33 activation signatures in severe neutrophilic asthma

BACKGROUND

Interleukin (IL)-33 is an upstream regulator of type 2 (T2) eosinophilic inflammation and has been proposed as a key driver of some asthma phenotypes.

OBJECTIVE

To derive gene signatures from in vitro studies of IL-33-stimulated cells and use these to determine IL-33-associated enrichment patterns in asthma.

METHODS

Signatures downstream of IL-33 stimulation were derived from our in vitro study of human mast cells and from public datasets of in vitro stimulated human basophils, type 2 innate lymphoid cells (ILC2), regulatory T cells (Treg) and endothelial cells. Gene Set Variation Analysis (GSVA) was used to probe U-BIOPRED and ADEPT sputum transcriptomics to determine enrichment scores (ES) for each signature according to asthma severity, sputum granulocyte status and previously defined molecular phenotypes.

RESULTS

IL-33-activated gene signatures were cell-specific with little gene overlap. Individual signatures, however, were associated with similar signalling pathways (TNF, NF-κB, IL-17 and JAK/STAT signalling) and immune cell differentiation pathways (Th17, Th1 and Th2 differentiation). ES for IL-33-activated gene signatures were significantly enriched in asthmatic sputum, particularly in patients with neutrophilic and mixed granulocytic phenotypes. IL-33 mRNA expression was not elevated in asthma whereas the expression of mRNA for IL1RL1, the IL-33 receptor, was up-regulated in the sputum of severe eosinophilic asthma. The mRNA expression for IL1RAP, the IL1RL1 co-receptor, was greatest in severe neutrophilic and mixed granulocytic asthma.

CONCLUSIONS

IL-33-activated gene signatures are elevated in neutrophilic and mixed granulocytic asthma corresponding with IL1RAP co-receptor expression. This suggests incorporating T2-low asthma in anti-IL-33 trials.

Benefits of Budesonide/Glycopyrronium/Formoterol Fumarate Dihydrate on COPD Exacerbations, Lung Function, Symptoms, and Quality of Life Across Blood Eosinophil Ranges: A Post-Hoc Analysis of Data from ETHOS

Purpose

Blood eosinophil (EOS) count can guide treatment decisions for chronic obstructive pulmonary disease (COPD). In the 52-week ETHOS study (NCT02465567), budesonide/glycopyrronium/formoterol fumarate dihydrate (BGF) triple therapy at two inhaled corticosteroid doses reduced moderate/severe exacerbation rates and improved lung function, symptoms, and disease-related quality of life (QoL) versus dual therapy with glycopyrronium/formoterol fumarate dihydrate (GFF) or budesonide/formoterol fumarate dihydrate (BFF) in patients with moderate-to-very severe COPD. This subgroup analysis evaluated treatment benefits in ETHOS by baseline EOS count.

Methods

Patients (40-80 years) with a COPD history were randomly assigned 1:1:1:1 to receive BGF 320/14.4/10 µg, BGF 160/14.4/10 µg, GFF 14.4/10 µg, or BFF 320/10 µg via a metered-dose inhaler. This post-hoc analysis assessed endpoints by baseline EOS count using Global Initiative for Obstructive Lung Disease thresholds (<100, ≥100, ≥100-<300, ≥300 cells/mm³), and investigated continuous relationships between treatment effects and EOS count on exacerbations, symptoms, disease-related QoL, lung function, and safety.

Results

In the modified intention-to-treat population (n=8509), 82.6% had EOS counts ≥100 cells/mm³. BGF 320 reduced moderate/severe exacerbation rates versus GFF in the ≥100, ≥100-<300, and ≥300 subgroups; treatment differences increased with EOS count. BGF 320 improved rescue medication use and lung-function outcomes across all subgroups, and St George's Respiratory Questionnaire total score, Transition Dyspnea Index focal score, and Exacerbations of Chronic Pulmonary Disease Tool total score in all except the <100 subgroup versus GFF. Benefits of BGF 320 versus BFF were generally consistent across subgroups. Safety data were comparable across subgroups.

Conclusion

Benefits of BGF versus GFF were observed across EOS counts, particularly at ≥100 cells/mm³; versus BFF, benefits were largely independent of EOS. These findings confirm that benefits of ICS-containing triple therapy are not restricted to EOS counts ≥300 cells/mm³, supporting recommendations to consider triple therapy in patients with an exacerbation history and EOS counts ≥100 cells/mm³.

Increased mast cell activation in eosinophilic chronic obstructive pulmonary disease

Objectives

A subset of chronic obstructive pulmonary disease (COPD) patients have increased numbers of airway eosinophils associated with elevated markers of T2 inflammation. This analysis focussed on mast cell counts and mast cell‐related gene expression in COPD patients with higher vs lower eosinophil counts.

Methods

We investigated gene expression of tryptase (TPSAB1), carboxypeptidase A3 (CPA3), chymase (CMA1) and two mast cell specific gene signatures; a bronchial biopsy signature (MC_bb) and an IgE signature (MC_IgE) using sputum cells and bronchial epithelial brushings. Gene expression analysis was conducted by RNA‐sequencing. We also examined bronchial biopsy mast cell numbers by immunohistochemistry.

Results

There was increased expression of TPSAB1, CPA3 and MC_bb in eosinophil^high than in eosinophil^low COPD patients in sputum cells and bronchial epithelial brushings (fold change differences 1.21 and 1.28, respectively, P < 0.01). Mast cell gene expression was associated with markers of T2 and eosinophilic inflammation (IL13, CLCA1, CST1, CCL26, eosinophil counts in sputum and bronchial mucosa; rho = 0.4–0.8; P < 0.05). There was no difference in MC_IgE gene expression between groups. There was no difference in the total number of bronchial biopsy mast cells between groups.

Conclusion

These results demonstrate that eosinophilic inflammation is associated with altered mast cell characteristics in COPD patients, implicating mast cells as a component of T2 inflammation present in a subset of COPD patients.

[COPD and eosinophils]

COPD is a major cause of morbidity and mortality worldwide. As research progresses, new patient phenotypes are being defined, providing hope for more personalized management of the disease. A significant proportion of patients present with an increased level of blood eosinophils, which may reflect bronchial eosinophilic inflammation. The aims of this article are to characterize the role of eosinophils in COPD in terms of pathophysiology, associated respiratory symptoms, impact on treatment and, finally, to consider different future treatment options.

Menthone supplementation protects from allergic inflammation in the lungs of asthmatic mice

To screen potent terpenoid compounds against allergic inflammation in vitro and in vivo, five terpenoid compounds including menthone, farnesol, oridonin, β-escin and lupeol, were first selected to compare their anti-allergic inflammation potential using mouse lung mast cells in vitro. Among five selected terpenoid compounds, just menthone treatment decreased TNF-α/IL-10 secretion ratios in lipopolysaccharide -stimulated mast cells in vitro. As a result, menthone was further chosen to treat ovalbumin (OVA)-sensitized and challenged BALB/c mice by gavage for 5 weeks. There were six groups including dietary control (DC group, 0 mg menthone/kg b.w./day), 8 (ML group), 40 (MM group) as well as 200 mg menthone/kg b.w./day (MH group) by gavage, positive control (PC group, 3 mg dexamethasone/kg b.w. by gavage before OVA challenge) and non-treatment control (NTC group, normal mice without treatment) in the experiment. Changes of inflammatory mediators, cell distribution, Th1/Th2 and pro-/anti-inflammatory cytokines secretion as well as relative gene expression amounts of six receptors related to allergic inflammation in the lungs and airways were measured. The results showed that middle menthone supplementation (40 mg menthone/kg b.w./day) in vivo decreased protein and eotaxin, but increased Th1 cytokine levels in the bronchoalveolar lavage fluid. Menthone supplementation inhibited eosinophilia, mast cell degranulation, chemokine (C-C motif) receptor 3 (CC receptor 3) and chemokine (C-X-C motif) receptor 1 (CXC receptor 1) gene expression amounts in the lungs, but restored the percentage of monocytes/macrophages. Our results suggest that menthone supplementation may alleviate allergic asthma through regulating airway allergic inflammation, protein overproduction, eosinophils infiltration, Th1/Th2 immune balance, CC receptor 3 and CXC receptor 1 gene expression amounts in the lungs but restoring the percentage of monocytes/macrophages in allergic asthmatic mice.

Identification of key genes and pathways in chronic rhinosinusitis with nasal polyps and asthma comorbidity using bioinformatics approaches

Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) and asthma comorbidity (ACRSwNP) present severe symptoms and are more likely to relapse. However, the pathogenesis of ACRSwNP is not fully understood. The aim of this study was to explore the underlying pathogenesis of ACRSwNP using bioinformatics approaches. ACRSwNP-related differentially expressed genes (DEGs) were identified by the analysis of the GSE23552 dataset. The clusterProfiler R package was used to carry out functional and pathway enrichment analysis. A protein–protein interaction (PPI) network was built using the STRING database to explore key genes in the pathogenesis of ACRSwNP. The bioinformatics analysis results were verified through qRT-PCR. The Connectivity Map (CMap) database was used to predict potential drugs for the treatment of ACRSwNP. A total of 36 DEGs were identified, which were mainly enriched in terms of regulation of immune response and detection sensory perception of taste. Thirteen hub genes including AZGP1, AQP9, GAPT, PIP, and PRR4 were identified as potential hub genes in ACRSwNP from the PPI network. Analysis of the GSE41861 dataset showed that upregulation of CST1 in nasal mucosa was associated with asthma. qRT-PCR detection confirmed the bioinformatics analysis results. Tacrolimus and spaglumic acid were identified as potential drugs for the treatment of ACRSwNP from the CMap database. The findings of this study provide insights into the pathogenesis of ACRSwNP and may provide a basis for the discovery of effective therapeutic modalities for ACRSwNP.

Precision medicine in chronic obstructive pulmonary disease

Over the last 20 years, it has become possible to use a precision medicine approach to the management of chronic obstructive pulmonary disease (COPD). Clinical and physiological features as well as a blood biomarker can be used to target treatments to patients most likely to benefit and avoid treatment in patients less likely to benefit. Future advances in a precision medicine approach to COPD will depend on more precise characterization of individual patients, possibly using quantitative imaging, new physiological techniques, novel biomarkers and genetic profiling. Precision medicine has led to significant improvements in the management of COPD and clinicians should use all available information to optimize the treatment of individual patients.

Blood Eosinophils and Chronic Obstructive Pulmonary Disease: A GOLD Science Committee 2022 Review

COPD is a heterogeneous condition. Some patients benefit from treatment with inhaled corticosteroids (ICS) but this requires a precision medicine approach, based on clinical characteristics (phenotyping) and biological information (endotyping) in order to select patients most likely to benefit. The GOLD 2019 report recommended using exacerbation history combined with blood eosinophil counts (BEC) to identify such patients. Importantly, the relationship between BEC and ICS effects is continuous; no / small effects are observed at lower BEC, with increasing effects at higher BEC. The GOLD 2022 report has added additional evidence and recommendations concerning the use of BEC in COPD in clinical practice. Notably, associations have been demonstrated in COPD patients between higher BEC and increased levels of type-2 inflammation in the lungs. These differences in type-2 inflammation can explain the differential ICS response according to BEC. Additionally, lower BEC are associated with greater presence of proteobacteria, notably haemophilus, and increased bacterial infections and pneumonia risk. These observations support management strategies that use BEC to help identify subgroups with increased ICS response (higher BEC) or increased risk of bacterial infection (lower BEC). Recent studies in younger individuals without COPD have also shown that higher BEC are associated with increased risk of FEV1 decline and the development of COPD. Here we discuss and summarise the GOLD 2022 recommendations concerning the use of BEC as a biomarker that can facilitate a personalised management approach in COPD.

Factors Influencing the Stability of Blood Eosinophils Counts in Chronic Obstructive Pulmonary Disease Patients

Blood eosinophil (EOS) has recently been recognized as a biomarker for chronic obstructive pulmonary disease (COPD) patients. However, few studies have concentrated on the stability of blood eosinophil counts (BEC), and those studies have produced varying results. With further research, we have found minor drawbacks and vulnerabilities that lead to the variability of the results. This paper enumerates several areas of relevant research with varying conclusions to further investigate the stability of BEC in COPD patients.

Treatment Trials in Young Patients with Chronic Obstructive Pulmonary Disease and Pre-Chronic Obstructive Pulmonary Disease Patients: Time to Move Forward

Chronic obstructive pulmonary disease (COPD) is the end result of a series of dynamic and cumulative gene-environment interactions over a lifetime. The evolving understanding of COPD biology provides novel opportunities for prevention, early diagnosis, and intervention. To advance these concepts, we propose therapeutic trials in two major groups of subjects: "young" individuals with COPD and those with pre-COPD. Given that lungs grow to about 20 years of age and begin to age at approximately 50 years, we consider "young" patients with COPD those patients in the age range of 20-50 years. Pre-COPD relates to individuals of any age who have respiratory symptoms with or without structural and/or functional abnormalities, in the absence of airflow limitation, and who may develop persistent airflow limitation over time. We exclude from the current discussion infants and adolescents because of their unique physiological context and COPD in older adults given their representation in prior randomized controlled trials (RCTs). We highlight the need of RCTs focused on COPD in young patients or pre-COPD to reduce disease progression, providing innovative approaches to identifying and engaging potential study subjects. We detail approaches to RCT design, including potential outcomes such as lung function, patient-reported outcomes, exacerbations, lung imaging, mortality, and composite endpoints. We critically review study design components such as statistical powering and analysis, duration of study treatment, and formats to trial structure, including platform, basket, and umbrella trials. We provide a call to action for treatment RCTs in 1) young adults with COPD and 2) those with pre-COPD at any age.

Inhaled Phosphodiesterase Inhibitors for the Treatment of Chronic Obstructive Pulmonary Disease

Phosphodiesterase (PDE) 4 inhibitors prevent the metabolism of cyclic adenosine monophosphate, thereby reducing inflammation. Inhaled PDE4 inhibitors aim to restrict systemic drug exposure to enhance the potential for clinical benefits (in the lungs) versus adverse events (systemically). The orally administered PDE4 inhibitor roflumilast reduces exacerbation rates in the subgroup of chronic obstructive pulmonary disease patients with a history of exacerbations and the presence of chronic bronchitis, but can cause PDE4 related adverse effects due to systemic exposure. CHF6001 is an inhaled PDE4 inhibitor, while inhaled ensifentrine is an inhibitor of both PDE3 and PDE4; antagonism of PDE3 facilitates smooth muscle relaxation and hence bronchodilation. These inhaled PDE inhibitors have both reported positive findings from early phase clinical trials, and have been well tolerated. Longer term trials are needed to firmly establish the clinical benefits of these drugs.

Airway Bacteria Quantification Using Polymerase Chain Reaction Combined with Neutrophil and Eosinophil Counts Identifies Distinct COPD Endotypes

BACKGROUND

Chronic obstructive pulmonary disease (COPD) inflammatory endotypes are associated with different airway microbiomes. We used quantitative polymerase chain reaction (qPCR) analysis of sputum samples to establish the bacterial load upper limit in healthy controls; these values determined the bacterial colonisation prevalence in a longitudinal COPD cohort. Bacteriology combined with sputum inflammatory cells counts were used to investigate COPD endotypes.

METHODS

Sixty COPD patients and 15 healthy non-smoking controls were recruited. Sputum was analysed by qPCR (for Haemophilus influenzae, Moraxella catarrhalis, Streptococcus pneumoniae and Psuedomonas aeruginosa) and sputum differential cell counts at baseline and 6 months.

RESULTS

At baseline and 6 months, 23.1% and 25.6% of COPD patients were colonised with H. influenzae, while colonisation with other bacterial species was less common, e.g., S. pneumoniae-1.9% and 5.1%, respectively. H. influenzae + ve patients had higher neutrophil counts at baseline (90.1% vs. 67.3%, p < 0.01), with similar results at 6 months. COPD patients with sputum eosinophil counts ≥3% at ≥1 visit rarely showed bacterial colonisation.

CONCLUSIONS

The prevalence of H. influenzae colonisation was approximately 25%, with low colonisation for other bacterial species. H. influenzae colonisation was associated with sputum neutrophilia, while eosinophilic inflammation and H. influenzae colonisation rarely coexisted.

Clinical Predictors of High Blood Eosinophils in Chronic Obstructive Pulmonary Disease

Purpose

Elevated blood eosinophils have been implicated in chronic obstructive pulmonary disease (COPD) progression and exacerbation. We aim to investigate clinical predictors of high blood eosinophils in a Chinese COPD cohort.

Patients and Methods

We conducted a retrospective cohort study in Sichuan province, a Southwest province with high prevalence of COPD in China. All patients in this cohort were extracted from the Chinese Pulmonary Health study, a large cross-sectional study on COPD epidemiology in China. Demographics, personal and family history, living condition, spirometry and blood eosinophil counts were obtained. Univariate and multiple linear regression analyses were performed to determine predictors of high blood eosinophils.

Results

A total of 375 COPD patients were included in this cohort. The median absolute blood eosinophil count was 138.8 cells/μL, and the prevalence of COPD with high blood eosinophils was 66.7% and 14.7% when using the thresholds of 100 cells/μL and 300 cells/μL, respectively. Univariate analyses indicated that male gender, lower body mass index, high-density lipoprotein (HDL), lower family income, raising pets and biomass use were significantly associated with high blood eosinophils (p < 0.05). Multiple linear regression model further revealed male gender (unstandardized coefficient (B)=66.125, 95% confidence intervals (CI) 16.350 to 115.900, p=0.009), age (B=2.819, 95% CI 0.639 to 5.000, p=0.012) predicted high blood eosinophil level, whereas HDL (B=−64.682, 95% CI −123.451 to −5.914, p=0.031) was a negative predictor for high blood eosinophils.

Conclusion

This retrospective cohort study suggests male gender, oldness and lower HDL could be clinical predictors of high blood eosinophils in Chinese COPD patients.

Molecular markers of type 2 airway inflammation are similar between eosinophilic severe asthma and eosinophilic chronic obstructive pulmonary disease

BACKGROUND

Airway and systemic eosinophilia are important treatable traits in both severe asthma and COPD. The molecular basis of eosinophilia in COPD is poorly understood but could involve type 2 cytokines (IL5, IL13) and prostaglandin D₂ (PGD₂ ).

METHODS

This study included non-obstructive airways disease (OAD) controls (n = 19), a COPD cohort (n = 96) and a severe asthma cohort (n = 84). Demographics, exacerbation history, disease impact (SGRQ) and spirometry were assessed. Participants were categorized as eosinophilic using either sputum eosinophil proportion (≥3%) or blood eosinophil count (≥300/μL). Sputum type 2 inflammatory measures included PGD₂ by ELISA and gene expression (qPCR) of IL5, IL13 and the haematopoietic PGD₂ synthase (HPGDS).

RESULTS

Type 2 markers did not differ across groups except HPGDS mRNA which was highest in non-OAD controls and lowest in COPD. IL5 and IL13 mRNA and PGD₂ levels were significantly increased in eosinophilic vs non-eosinophilic severe asthma but did not differ between eosinophilic COPD and eosinophilic severe asthma or non-eosinophilic COPD. HPGDS expression was higher in eosinophilic severe asthma compared with eosinophilic COPD. Results were similar using sputum or blood eosinophil cut-offs. Sputum IL5 and IL13 were highly intercorrelated in severe asthma (r = 0.907, p < 0.001) and COPD (r = 0.824, p < 0.001), were moderately correlated with sputum eosinophils in severe asthma (IL5 r = 0.440, p < 0.001; IL13 r = 0.428, p < 0.001) and were weakly correlated in COPD (IL5 r = 0.245, p < 0.05; IL13 r = 0.317, p < 0.05).

CONCLUSIONS

Molecular markers of type 2 airway inflammation do not differ between eosinophilic asthma and eosinophilic COPD; however, the relationship between eosinophilia and type 2 airway markers appears weaker in COPD than in severe asthma.

Nasal upregulation of CST1 in dog-sensitised children with severe allergic airway disease

Background

The clinical presentation of children sensitised to dog dander varies from asymptomatic to severe allergic airway disease, but the genetic mechanisms underlying these differences are not clear. The objective of the present study was to investigate nasal transcriptomic profiles associated with dog dander sensitisation in school children and to reveal clinical symptoms related with these profiles.

Methods

RNA was extracted from nasal epithelial cell brushings of children sensitised to dog dander and healthy controls. Blood sample analyses included IgE against dog dander, dog allergen molecules, other airborne and food allergens, basophil activation and white blood cell counts. Clinical history of asthma and rhinitis was recorded, and lung function was assessed (spirometry, methacholine provocation and exhaled nitric oxide fraction).

Results

The most overexpressed gene in children sensitised to dog dander compared to healthy controls was CST1, coding for Cystatin 1. A cluster of these children with enhanced CST1 expression showed lower forced expiratory volume in 1 s, increased bronchial hyperreactivity, pronounced eosinophilia and higher basophil allergen threshold sensitivity compared with other children sensitised to dog dander. In addition, multi-sensitisation to lipocalins was more common in this group.

Conclusions

Overexpression of CST1 is associated with more severe allergic airway disease in children sensitised to dog dander. CST1 is thus a possible biomarker of the severity of allergic airway disease and a possible therapeutic target for the future treatment of airborne allergy.

Targeted therapy in eosinophilic chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common and preventable airway disease causing significant worldwide mortality and morbidity. Lifetime exposure to tobacco smoking and environmental particles are the two major risk factors. Over recent decades, COPD has become a growing public health problem with an increase in incidence. COPD is defined by airflow limitation due to airway inflammation and small airway remodelling coupled to parenchymal lung destruction. Most patients exhibit neutrophil-predominant airway inflammation combined with an increase in macrophages and CD8⁺ T-cells. Asthma is a heterogeneous chronic inflammatory airway disease. The most studied subtype is type 2 (T2) high eosinophilic asthma, for which there are an increasing number of biologic agents developed. However, both asthma and COPD are complex and share common pathophysiological mechanisms. They are known as overlapping syndromes as approximately 40% of patients with COPD present an eosinophilic airway inflammation. Several studies suggest a putative role of eosinophilia in lung function decline and COPD exacerbation. Recently, pharmacological agents targeting eosinophilic traits in uncontrolled eosinophilic asthma, especially monoclonal antibodies directed against interleukins (IL-5, IL-4, IL-13) or their receptors, have shown promising results. This review examines data on the rationale for such biological agents and assesses efficacy in T2-endotype COPD patients.

Patients with severe COPD and eosinophilic inflammation experience uncontrolled symptoms despite optimal pharmaceutical treatment. The development of new biomarkers is needed for better phenotyping of patients to propose innovative targeted therapy.https://bit.ly/2KzWuNO

Pharmacological treatment of stable chronic obstructive pulmonary disease

Pharmacological treatment for chronic obstructive pulmonary disease (COPD) aims to alleviate symptoms and reduce the future risk of events such as exacerbations, disease progression and death. The heterogeneity of COPD results in variable responses to pharmacological interventions. COPD treatment has evolved towards a precision medicine approach, integrating clinical and biomarker information in order to optimize treatment decisions for each individual. The evidence supporting the use of blood eosinophil counts to predict responses to inhaled corticosteroids (ICS) in COPD patients has led to the adoption of this biomarker for use in clinical practice. The development of novel double and triple inhaled combination treatments containing long-acting bronchodilators with or without ICS has involved some landmark randomized controlled trials in COPD patients. These studies have provided valuable evidence to direct the use of different classes of combination treatments. However, there are still some unresolved questions and debates. This review article describes the advances in the pharmacological treatment of COPD, particularly the personalization of treatment. The evidence base for current recommendations is discussed, and controversial issues are dissected.

Blood eosinophil counts and the development of obstructive lung disease: the Kangbuk Samsung Health Study

The impact of blood eosinophil counts on the development of chronic obstructive lung disease (COPD) is unknown. We investigated whether a higher blood eosinophil counts was associated with the risk of developing obstructive lung disease (OLD) in a large cohort of men and women free lung disease at baseline.Cohort study of 359 456 Korean adults without a history of asthma and without OLD at baseline who participated in health screening exams including spirometry. OLD was defined as pre-bronchodilator FEV₁/FVC<0.7 and FEV₁<80% predicted.After a median follow-up of 5.6 years (interquartile range, 2.9-9.2), 5008 participants developed incident OLD (incidence rate, 2.1 per 1000 person-years; 95% CI, 2.1-2.2). In the fully-adjusted model, the HR (95% CI) for incident OLD comparing eosinophil counts of 100-<200, 200-<300, 300-<500 and ≥500 cells·μL^-1 to <100 cells·μL^-1 were 1.07 (1.00-1.15), 1.30 (1.20-1.42), 1.46 (1.33-1.60) and 1.72 (1.51-1.95) (p for trend <0.001). These associations were consistent in clinically relevant subgroups, including never, former, and current smokers.In this large longitudinal cohort study, blood eosinophil counts were positively associated with the risk of developing of OLD. Our findings indicate a potential role of eosinophil count as an independent risk factor for developing COPD.

COPD patients with chronic bronchitis and higher sputum eosinophil counts show increased type-2 and PDE4 gene expression in sputum

Chronic obstructive pulmonary disease (COPD) patients with higher eosinophil counts are associated with increased clinical response to phosphodiesterase‐4‐inhibitors (PDE4i). However, the underlying inflammatory mechanisms associated with this increased response is not yet elucidated. This post hoc analysis focused on sputum gene expression in patients with chronic bronchitis who underwent 32‐day treatment with two doses of the inhaled PDE4i CHF6001 (tanimilast) or placebo on top of triple therapy. Biological characterization and treatment effects were assessed between patients with different sputum eosinophil levels (eosinophil^high ≥ 3%; eosinophil^low < 3%) at baseline (primary samples) or at the end of the treatment of the placebo arm (validation samples). Forty‐one genes were differentially expressed in primary samples (p‐adjusted for false discovery rate < 0.05); all up‐regulated in eosinophil^high patients and functionally enriched for type‐2 and PDE4 inflammatory processes. Eleven out of nineteen genes having immune system biological processes annotations including IL5RA, ALOX15, IL1RL1, CLC, GATA1 and PDE4D were replicated using validation samples. The expression of a number of these inflammatory mediators was reduced by tanimilast treatment, with greater effects observed in eosinophil^high patients. These findings suggest that type‐2 and PDE4 overexpression in COPD patients with higher sputum eosinophil counts contribute to the differential clinical response to PDE4i observed in previous clinical trials.

ST2 expression and release by the bronchial epithelium is downregulated in asthma

BACKGROUND

The airway epithelium plays an important role in wound repair, host defense and is involved in the immunopathogenesis of asthma. Genome wide association studies have described associations between ST2/Interleukin (IL)-33 genes in asthma, but its role in bronchial epithelium is unclear.

METHODS

ST2 expression was examined in subjects with asthma and healthy controls in bronchial epithelium from biopsies (n = 27 versus n = 9) and brushings (n = 34 versus n = 20) by immunohistochemistry and RNA-Seq. In human primary bronchial epithelial cells ST2 mRNA and protein expression were assessed by qPCR, flow cytometry, Western blotting, and immunofluorescence. IL-33 function in epithelial cells was examined by intracellular calcium measurements, wound healing assays, and synthetic activation by gene array and ELISA.

RESULTS

Bronchial epithelial ST2 protein expression was significantly decreased in biopsies in subjects with asthma compared to healthy controls (P = .039). IL1RL1 gene expression in bronchial brushes was not different between health and disease. In vitro primary bronchial epithelial cells expressed ST2 and IL-33 stimulation led to an increase in intracellular calcium, altered gene expression, but had no effect upon wound repair. Epithelial cells released sST2 spontaneously, which was reduced following stimulation with TNFα or poly-IC. Stimulation by TNFα or poly-IC did not affect the total ST2 expression by epithelial cell whereas surface ST2 decreased in response to TNFα, but not poly-IC.

CONCLUSION

In asthma, bronchial epithelium protein expression of ST2 is decreased. Our in vitro findings suggest that this decrease might be a consequence of the pro-inflammatory environment in asthma or in response to viral infection.

Blood eosinophil count and airway epithelial transcriptome relationships in COPD versus asthma

BACKGROUND

Whether the clinical or pathophysiologic significance of the "treatable trait" high blood eosinophil count in COPD is the same as for asthma remains controversial. We sought to determine the relationship between the blood eosinophil count, clinical characteristics and gene expression from bronchial brushings in COPD and asthma.

METHODS

Subjects were recruited into a COPD (emphysema versus airway disease [EvA]) or asthma cohort (Unbiased BIOmarkers in PREDiction of respiratory disease outcomes, U-BIOPRED). We determined gene expression using RNAseq in EvA (n = 283) and Affymetrix microarrays in U-BIOPRED (n = 85). We ran linear regression analysis of the bronchial brushings transcriptional signal versus blood eosinophil counts as well as differential expression using a blood eosinophil > 200 cells/μL as a cut-off. The false discovery rate was controlled at 1% (with continuous values) and 5% (with dichotomized values).

RESULTS

There were no differences in age, gender, lung function, exercise capacity and quantitative computed tomography between eosinophilic versus noneosinophilic COPD cases. Total serum IgE was increased in eosinophilic asthma and COPD. In EvA, there were 12 genes with a statistically significant positive association with the linear blood eosinophil count, whereas in U-BIOPRED, 1197 genes showed significant associations (266 positive and 931 negative). The transcriptome showed little overlap between genes and pathways associated with blood eosinophil counts in asthma versus COPD. Only CST1 was common to eosinophilic asthma and COPD and was replicated in independent cohorts.

CONCLUSION

Despite shared "treatable traits" between asthma and COPD, the molecular mechanisms underlying these clinical entities are predominately different.