Factors associated with plasma IL-33 levels in patients with chronic obstructive pulmonary disease

IL-33 in patients with periodontitis and chronic obstructive pulmonary disease

OBJECTIVE

A link between periodontitis and chronic obstructive pulmonary disease (COPD) has been identified, and interleukin-33 (IL-33) may play an important role in the common inflammatory mechanisms of these diseases. This study analyzed the associations of the serum IL-33 level with the occurrence and severity of periodontitis and COPD.

METHODS

A total of 161 participants were divided into four groups: healthy volunteers, periodontitis patients, COPD patients, and patients with both COPD and periodontitis. Associations between serum IL-33 levels were measured by enzyme-linked immunosorbent assay, and clinical factors as well as the risks and severity of periodontitis and COPD were analyzed.

RESULTS

Serum IL-33 levels were lower in all patient groups than in healthy controls. A trend toward lower IL-33 levels was observed among patients with both diseases compared with patients with either disease alone. The serum IL-33 level was also inversely associated with the severity of periodontitis and COPD. The serum IL-33 level was negatively associated with risks of periodontitis and COPD, indicating that IL-33 is likely involved in the pathophysiologic mechanism of the relationship between COPD and periodontitis.

CONCLUSION

This study advances our understanding of the association between COPD and periodontitis and provides new bases for COPD prevention and treatment.

Endotyping Eosinophilic Inflammation in COPD with ELAVL1, ZfP36 and HNRNPD mRNA Genes

Background: Chronic obstructive pulmonary disease (COPD) is a common disease characterized by progressive airflow obstruction, influenced by genetic and environmental factors. Eosinophils have been implicated in COPD pathogenesis, prompting the categorization into eosinophilic and non-eosinophilic endotypes. This study explores the association between eosinophilic inflammation and mRNA expression of ELAVL1, ZfP36, and HNRNPD genes, which encode HuR, TTP and AUF-1 proteins, respectively. Additionally, it investigates the expression of IL-9 and IL-33 in COPD patients with distinct eosinophilic profiles. Understanding these molecular associations could offer insights into COPD heterogeneity and provide potential therapeutic targets. Methods: We investigated 50 COPD patients, of whom 21 had eosinophilic inflammation and 29 had non-eosinophilic inflammation. Epidemiological data, comorbidities, and pulmonary function tests were recorded. Peripheral blood mononuclear cells were isolated for mRNA analysis of ELAVL1, ZfP36, and HNRNPD genes and serum cytokines (IL-9, IL-33) were measured using ELISA kits. Results: The study comprised 50 participants, with 66% being male and a mean age of 68 years (SD: 8.9 years). Analysis of ELAVL1 gene expression revealed a 0.45-fold increase in non-eosinophilic and a 3.93-fold increase in eosinophilic inflammation (p = 0.11). For the ZfP36 gene, expression was 6.19-fold higher in non-eosinophilic and 119.4-fold higher in eosinophilic groups (p = 0.07). Similarly, HNRNPD gene expression was 0.23-fold higher in non-eosinophilic and 0.72-fold higher in eosinophilic inflammation (p = 0.06). Furthermore, serum levels of IL-9 showed no statistically significant difference between the eosinophilic and non-eosinophilic group (58.03 pg/mL vs. 52.55 pg/mL, p = 0.98). Additionally, there was no significant difference in IL-33 serum levels between COPD patients with eosinophilic inflammation and those with non-eosinophilic inflammation (39.61 pg/mL vs. 37.94 pg/mL, p = 0.72). Conclusions: The data suggest a notable trend, lacking statistical significance, towards higher mRNA expression for the ZfP36 and HNRNPD genes for COPD patients with eosinophilic inflammation compared to those with non-eosinophilic inflammation.

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 alarmins: a new target to treat chronic respiratory diseases

INTRODUCTION

In response to injury, epithelial cells release alarmins including thymic stromal lymphopoietin (TSLP), high mobility group-box-1 (HMGB1), interleukin (IL)-33 and -25 that can initiate innate immune responses. These alarmins are recognized as activators of T2-immune responses characteristic for asthma, but recent evidence highlighted their role in non-T2 inflammation, airway remodeling, and pulmonary fibrosis making them an attractive therapeutic target for chronic respiratory diseases (CRD).

AREAS COVERED

In this review, firstly we discuss the role of TSLP, IL-33, IL-25, and HMGB1 in the pathogenesis of asthma, COPD, idiopathic pulmonary fibrosis, and cystic fibrosis according to the published data. In the second part, we summarize the current evidence concerning the efficacy of the antialarmin therapies in CRD. Recent clinical trials showed that anti-TSLP and IL-33/R antibodies can improve severe asthma outcomes. Blocking the IL-33-mediated pathway decreased the exacerbation rate in COPD patients with more important benefit for former-smokers.

EXPERT OPINION

Despite progress in the understanding of the alarmins' role in the pathogenesis of CRD, all their mechanisms of action are not yet identified. Blocking IL-33 and TSLP pathways offers an interesting option to treat severe asthma and COPD, but future investigations are needed to establish their place in the treatment strategies.

Association between Serum Levels of Interleukin-25/Thymic Stromal Lymphopoietin and the Risk of Exacerbation of Chronic Obstructive Pulmonary Disease

Th2 inflammation is associated with various characteristics of patients with chronic obstructive pulmonary disease (COPD). In this study, we analyzed the COPD exacerbation risk associated with serum levels of interleukin (IL)-25/thymic stromal lymphopoietin (TSLP) and eosinophils. We studied the KOCOSS cohort, a multicenter COPD cohort created by 54 medical centers in South Korea. We extracted data collected between April 2012 and August 2020. We measured serum levels of TSLP and IL-25 in those who agreed to provide blood, and assessed exacerbation risk according to each. In all, 562 patients were enrolled. The IL-25-high group had a lower St. George's Respiratory Questionnaire score than others, and the TSLP-high group had a poorer exercise capacity than the TSLP-low group. There were no significant differences in the forced expiratory volume in 1 s (FEV1), the levels of Th2 inflammatory biomarkers, or the exacerbation histories between the two groups. The 3-year decline in FEV1 was not significantly affected by IL-25 or TSLP levels. In terms of 1-year exacerbation risk, individuals in the IL-25-high group were at lower risk for moderate-to-severe exacerbation than others. A high TSLP level was associated with a lower risk of severe exacerbation but only in the eosinophil-low group. Serum levels of IL-25 are negatively correlated with moderate-to-severe exacerbation risk in this cohort. A negative correlation between severe exacerbation risk and TSLP level was apparent only in the eosinophil-low group.

Interleukin (IL)-33 immunobiology in asthma and airway inflammatory diseases

OBJECTIVE

Identify key features of IL-33 immunobiology important in allergic and nonallergic airway inflammatory diseases and potential therapeutic strategies to reduce disease burden.

DATA SOURCES

PubMed, clinicaltrials.gov.

STUDY SELECTIONS

A systematic and focused literature search was conducted of PubMed from March 2021 to December 2021 using keywords to either PubMed or BioMed Explorer including IL-33/ST2, genetic polymorphisms, transcription, translation, post-translation modification, nuclear protein, allergy, asthma, and lung disease. Clinical trial information on IL-33 was extracted from clinicaltrials.gov in August 2021.

RESULTS

In total, 72 publications with relevance to IL-33 immunobiology and/or clinical lung disease were identified (allergic airway inflammation/allergic asthma n = 26, non-allergic airway inflammation n = 9, COPD n = 8, lung fibrosis n = 10). IL-33 levels were higher in serum, BALF and/or lungs across inflammatory lung diseases. Eight studies described viral infections and IL-33 and 4 studies related to COVID-19. Mechanistic studies (n = 39) including transcript variants and post-translational modifications related to the immunobiology of IL-33. Single nucleotide polymorphism in IL-33 or ST2 were described in 9 studies (asthma n = 5, inflammatory bowel disease n = 1, mycosis fungoides n = 1, ankylosing spondylitis n = 1, coronary artery disease n = 1). Clinicaltrials.gov search yielded 84 studies of which 17 were related to therapeutic or biomarker relevance in lung disease.

CONCLUSION

An integral role of IL-33 in the pathogenesis of allergic and nonallergic airway inflammatory disease is evident with several emerging clinical trials investigating therapeutic approaches. Current data support a critical role of IL-33 in damage signaling, repair and regeneration of lungs.

Angiogenesis, Lymphangiogenesis, and Inflammation in Chronic Obstructive Pulmonary Disease (COPD): Few Certainties and Many Outstanding Questions

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, predominantly affecting the lung parenchyma and peripheral airways, that results in progressive and irreversible airflow obstruction. COPD development is promoted by persistent pulmonary inflammation in response to several stimuli (e.g., cigarette smoke, bacterial and viral infections, air pollution, etc.). Angiogenesis, the formation of new blood vessels, and lymphangiogenesis, the formation of new lymphatic vessels, are features of airway inflammation in COPD. There is compelling evidence that effector cells of inflammation (lung-resident macrophages and mast cells and infiltrating neutrophils, eosinophils, basophils, lymphocytes, etc.) are major sources of a vast array of angiogenic (e.g., vascular endothelial growth factor-A (VEGF-A), angiopoietins) and/or lymphangiogenic factors (VEGF-C, -D). Further, structural cells, including bronchial and alveolar epithelial cells, endothelial cells, fibroblasts/myofibroblasts, and airway smooth muscle cells, can contribute to inflammation and angiogenesis in COPD. Although there is evidence that alterations of angiogenesis and, to a lesser extent, lymphangiogenesis, are associated with COPD, there are still many unanswered questions.

Elastase- and LPS-Exposed Cpa3Cre/+ and ST2-/- Mice Develop Unimpaired Obstructive Pulmonary Disease

IL-33 and its receptor ST2, as well as mast cells and their mediators, have been implicated in the development of chronic obstructive pulmonary disease (COPD). However, whether mast cells and the ST2 receptor play a critical role in COPD pathophysiology remains unclear. Here, we performed repeated intranasal administrations of porcine pancreatic elastase and LPS for four weeks to study COPD-like disease in wildtype, ST2-deficient, and Cpa3^Cre/+ mice, which lack mast cells and have a partial reduction in basophils. Alveolar enlargement and changes in spirometry-like parameters, e.g. increased dynamic compliance and decreased expiratory capacity, were evident one day after the final LPS challenge and worsened over time. The elastase/LPS model also induced mild COPD-like airway inflammation, which encompassed a transient increase in lung mast cell progenitors, but not in mature mast cells. While ST2-deficient and Cpa3^Cre/+ mice developed reduced pulmonary function uninterruptedly, they had a defective inflammatory response. Importantly, both ST2-deficient and Cpa3^Cre/+ mice had fewer alveolar macrophages, known effector cells in COPD. Elastase/LPS instillation in vivo also caused increased bronchiole contraction in precision cut lung slices challenged with methacholine ex vivo, which occurred in a mast cell-independent fashion. Taken together, our data suggest that the ST2 receptor and mast cells play a minor role in COPD pathophysiology by sustaining alveolar macrophages.

Chronic obstructive pulmonary disease and atherosclerosis: common mechanisms and novel therapeutics

Chronic obstructive pulmonary disease (COPD) and atherosclerosis are chronic irreversible diseases, that share a number of common causative factors including cigarette smoking. Atherosclerosis drastically impairs blood flow and oxygen availability to tissues, leading to life-threatening outcomes including myocardial infarction (MI) and stroke. Patients with COPD are most likely to die as a result of a cardiovascular event, with 30% of all COPD-related deaths being attributed to cardiovascular disease (CVD). Both atherosclerosis and COPD involve significant local (i.e. lung, vasculature) and systemic inflammation and oxidative stress, of which current pharmacological treatments have limited efficacy, hence the urgency for the development of novel life-saving therapeutics. Currently these diseases must be treated individually, with no therapies available that can effectively reduce the likelihood of comorbid CVD other than cessation of cigarette smoking. In this review, the important mechanisms that drive atherosclerosis and CVD in people with COPD are explained and we propose that modulation of both the oxidative stress and the inflammatory burden will provide a novel therapeutic strategy to treat both the pulmonary and systemic manifestations related to these diseases.

Blood eosinophil counts in the general population and airways disease: a comprehensive review and meta-analysis

BACKGROUND

The clinical context for using blood eosinophil (EOS) counts as treatment-response biomarkers in asthma and COPD requires better understanding of EOS distributions and ranges. We describe EOS distributions and ranges published in asthma, COPD, control (non-asthma/COPD) and general populations.

METHODS

We conducted a comprehensive literature review and meta-analysis of observational studies (January 2008 to November 2018) that included EOS counts in asthma, severe asthma, COPD, control and general populations. Excluded studies had total sample sizes <200, EOS as inclusion criterion, hospitalised population only and exclusively paediatric participants.

RESULTS

Overall, 91 eligible studies were identified, most had total-population-level data available: asthma (39 studies), severe asthma (12 studies), COPD (23 studies), control (seven studies) and general populations (14 studies); some articles reported data for multiple populations. Reported EOS distributions were right-skewed (seven studies). Reported median EOS counts ranged from 157-280 cells·µL-1 (asthma, 22 studies); 200-400 cells·µL-1 (severe asthma, eight studies); 150-183 cells·µL-1 (COPD, six studies); and 100-160 cells·µL-1 (controls, three studies); and 100-200 cells·µL-1 (general populations, six studies). The meta-analysis showed that observed variability was mostly between studies rather than within studies. Factors reportedly associated with higher blood EOS counts included current smoking, positive skin-prick test, elevated total IgE, comorbid allergic rhinitis, age ≤18 years, male sex, spirometric asthma/COPD diagnosis, metabolic syndrome and adiposity.

CONCLUSION

EOS distribution and range varied by study population, and were affected by clinical factors including age, smoking history and comorbidities, which, regardless of severity, should be considered during treatment decision-making.

Soluble ST2 and All-Cause Mortality in Patients with Chronic Obstructive Pulmonary Disease—A 10-Year Cohort Study

Chronic obstructive pulmonary disease (COPD) is an inflammatory condition with constantly increasing mortality rates. Interleukin (IL)-33 and its decoy receptor, soluble suppression of tumorigenicity 2 (sST2), play a central role in the inflammatory response during infection. sST2 was suggested as a factor in the pathogenesis of COPD and emerged as a predictor of mortality in other non-communicable diseases. The role of sST2 as a predictor of mortality remains unclear in COPD yet. In this cohort study, we measured circulating concentrations of IL-33 and sST2 in the serum of patients with stable COPD (n = 59), patients with acute exacerbation of COPD (n = 29) and smoking (n = 20) and non-smoking controls (n = 20), using commercially available ELISAs, and investigated the prognostic role of sST2 in stable COPD. sST2 levels were significantly higher in COPD patients and smokers compared with non-smoking controls. We identified systolic blood pressure, forced expiratory volume in 1 s (FEV1% predicted), neutrophil count, lactate dehydrogenase and pack-years index as independent predictors of sST2 levels. During a median follow-up time of 10.6 years, 28 patients (47.5%) died. sST2 was an independent predictor of all-cause mortality in patients with COPD with a hazard ratio of 2.9 (95% CI 1.1–8.4, p = 0.035) per one standard deviation after adjustment for age, sex, pack-years, FEV1% predicted and C-reactive protein (CRP). sST2 concentrations are associated with severity of disease and long-term outcome in patients with COPD.

Pharmacokinetics and pharmacodynamics of itepekimab in healthy adults and patients with asthma: Phase I first-in-human and first-in-patient trials

Itepekimab is a monoclonal antibody that targets interleukin (IL‐33) and has been shown to reduce airway inflammation and associated tissue damage in preclinical studies. We assessed the safety, tolerability, pharmacokinetics (PKs), and pharmacodynamic profiles of single‐ascending and multiple‐ascending doses of itepekimab in two randomized, double‐blind, placebo‐controlled phase I studies. Healthy adults (N = 40) were randomized to the single‐dose study and patients with moderate asthma (N = 23) to the multiple‐dose study. Itepekimab was administered intravenously (0.3, 1, 3, or 10 mg/kg infusion) or subcutaneously (150 mg) in the single‐dose study and subcutaneously (75 or 150 mg weekly for 4 weeks) in the multiple‐dose study. Itepekimab exhibited linear PKs across studies and dose‐proportional increases in mean maximum concentration in serum and area under the concentration–time curve following single intravenous or multiple subcutaneous doses. Itepekimab demonstrated mean subcutaneous bioavailability of 59–73% and a long terminal half‐life (30.0–31.6 days). IL‐33 concentrations in most healthy participants and patients with asthma were undetectable at baseline. Following administration of itepekimab in both studies, total IL‐33 concentrations increased and blood eosinophils decreased, both with durable effect. Itepekimab was well‐tolerated in both studies with no detection of treatment‐emergent anti‐drug antibody responses.

Safety and efficacy of itepekimab in patients with moderate-to-severe COPD: a genetic association study and randomised, double-blind, phase 2a trial

BACKGROUND

Genetic data implicate IL-33 in asthma susceptibility. Itepekimab, a monoclonal antibody targeting IL-33, demonstrated clinical activity in asthma, with potential in chronic obstructive pulmonary disease (COPD). In this study we first aimed to test the hypothesis that genetic variants in the IL-33 pathway were also associated with COPD. On the basis of the strong association of IL-33 pathway genes with pulmonary diseases like asthma and COPD, we conducted this phase 2a trial to assess the safety and efficacy of itepekimab in patients with moderate-to-severe COPD on a stable regimen of triple-inhaled or double-inhaled background maintenance therapy.

METHODS

In this two-part study, genetic analyses of loss-of-function and gain-of-function variants in the IL-33 pathway, previously associated with asthma risk, were initially characterised for COPD. We then did a double-blind, phase 2a trial comparing itepekimab with placebo in patients with moderate-to-severe COPD despite standard therapy, at 83 study sites in ten countries. Patients aged 40-75 years who were current or former smokers, had been diagnosed with COPD for at least 1 year, and were on a stable regimen of triple-inhaled or double-inhaled background maintenance therapy, were randomly assigned (1:1) to receive itepekimab 300 mg or placebo, administered as two subcutaneous injections every 2 weeks for 24-52 weeks. The primary endpoint of the phase 2a trial was annualised rate of moderate-to-severe acute exacerbations of COPD during the treatment period. The key secondary outcome was change in prebronchodilator FEV₁ from baseline to weeks 16-24. Prespecified subgroup analyses were done for each of the endpoints, including by smoking status. Efficacy and safety analyses were done in all participants who received at least one dose of assigned treatment (modified intention-to-treat population). This trial is registered at ClinicalTrials.gov (NCT03546907).

FINDINGS

Genetic analyses demonstrated association of loss of function in IL33 with reduced COPD risk, and gain of function in IL33 and IL1RL1 variants with increased risk. Subsequent to this, in the phase 2 trial, 343 patients were randomly assigned to placebo (n=171) or itepekimab (n=172) from July 16, 2018, to Feb 19, 2020. Annualised rates of acute exacerbations of COPD were 1·61 (95% CI 1·32-1·97) in the placebo group and 1·30 (1·05-1·61) in the itepekimab group (relative risk [RR] 0·81 [95% CI 0·61-1·07], p=0·13), and least squares mean prebronchodilator FEV₁ change from baseline to weeks 16-24 was 0·0 L (SD 0·02) and 0·06 L (0·02; difference 0·06 L [95% CI 0·01-0·10], p=0·024). When analysis was restricted to former smokers, treatment with itepekimab was associated with nominally significant reductions in acute exacerbations of COPD (RR 0·58 [95% CI 0·39-0·85], p=0·0061) and FEV₁ improvement (least squares mean difference 0·09 L [0·02-0·15], p=0·0076) compared with placebo. Current smokers treated with itepekimab showed no treatment benefit versus placebo for exacerbations (RR 1·09 [0·74-1·61], p=0·65) or FEV₁ (least squares mean difference 0·02 [-0·05 to 0·09], p=0·54). Treatment-emergent adverse events (TEAEs) occurred in 135 (78%) patients in the itepekimab group and 136 (80%) in the placebo group. The most common TEAEs were nasopharyngitis (28 [16%] in the itepekimab group vs 29 [17%] in the placebo group), bronchitis (18 [10%] vs 14 [8%]), headache (14 [8%] vs 23 [13%]), and upper respiratory tract infection (13 [8%] vs 15 [9%]).

INTERPRETATION

The primary endpoint in the overall population was not met, subgroup analysis showed that itepekimab reduced exacerbation rate and improved lung function in former smokers with COPD. Two phase 3 clinical studies are ongoing to confirm the efficacy and safety profile of itepekimab in former smokers with COPD.

FUNDING

Sanofi and Regeneron Pharmaceuticals.

Association between plasma interleukin-33 level and acute exacerbation of chronic obstructive pulmonary disease

Background

The role of interleukin (IL)-33 in patients with chronic obstructive pulmonary disease (COPD) has not been well elucidated. The aim of this study is to analyze the association between plasma IL-33 level and acute exacerbation of COPD.

Methods

Plasma IL-33 was measured in 62 COPD patients during their stable state. Patients were prospectively followed up for 1 year. The expression of IL-33 was measured in lung tissue obtained from 38 patients who underwent surgery.

Results

The number of exacerbations was significantly higher in the high plasma IL-33 group compared with the low plasma IL-33 group. On Poisson regression analysis, high plasma IL-33 was associated with increased risk of exacerbation (incidence rate ratio = 2.166, P = 0.043). The expression of IL-33 in the lung was higher in COPD patients than in controls. The expression of IL-33 was significantly correlated with smoking pack years (R = 0.45, P < 0.01) and Forced expiratory volume in 1 s (%) (R = − 0.58, P < 0.01).

Conclusion

The plasma level of IL-33 in patients with COPD was significantly associated with the risk of exacerbation in prospective follow up. The expression of IL-33 in the lung was positively correlated with smoking and negatively correlated with lung function.

Natural history and mechanisms of COPD

The natural history of COPD is complex, and the disease is best understood as a syndrome resulting from numerous interacting factors throughout the life cycle with smoking being the strongest inciting feature. Unfortunately, diagnosis is often delayed with several longitudinal cohort studies shedding light on the long 'preclinical' period of COPD. It is now accepted that individuals presenting with different COPD phenotypes may experience varying natural history of their disease. This includes its inception, early stages and progression to established disease. Several scenarios regarding lung function course are possible, but it may conceptually be helpful to distinguish between individuals with normal maximally attained lung function in their early adulthood who thereafter experience faster than normal FEV₁ decline, and those who may achieve a lower than normal maximally attained lung function. This may be the main mechanism behind COPD in the latter group, as the decline in FEV₁ during their adult life may be normal or only slightly faster than normal. Regardless of the FEV₁ trajectory, continuous smoking is strongly associated with disease progression, development of structural lung disease and poor prognosis. In developing countries, factors such as exposure to biomass and sequelae after tuberculosis may lead to a more airway-centred COPD phenotype than seen in smokers. Mechanistically, COPD is characterized by a combination of structural and inflammatory changes. It is unlikely that all patients share the same individual or combined mechanisms given the heterogeneity of resultant phenotypes. Lung explants, bronchial biopsies and other tissue studies have revealed important features. At the small airway level, progression of COPD is clinically imperceptible, and the pathological course of the disease is poorly described. Asthmatic features can further add confusion. However, the small airway epithelium is likely to represent a key focus of the disease, combining impaired subepithelial crosstalk and structural/inflammatory changes. Insufficient resolution of inflammatory processes may facilitate these changes. Pathologically, epithelial metaplasia, inversion of the goblet to ciliated cell ratio, enlargement of the submucosal glands and neutrophil and CD8-T-cell infiltration can be detected. Evidence of type 2 inflammation is gaining interest in the light of new therapeutic agents. Alarmin biology is a promising area that may permit control of inflammation and partial reversal of structural changes in COPD. Here, we review the latest work describing the development and progression of COPD with a focus on lung function trajectories, exacerbations and survival. We also review mechanisms focusing on epithelial changes associated with COPD and lack of resolution characterizing the underlying inflammatory processes.

Role of Type2 Inflammatory Biomarkers in Chronic Obstructive Pulmonary Disease

Airway inflammation in chronic obstructive pulmonary disease (COPD) is typically thought to be driven by Type1 immune responses, while Type2 inflammation appears to be present in definite proportions in the stable state and during exacerbations. In fact, some COPD patients showed gene expression of Type2 inflammation in the airway, and this subset was associated with the inhaled corticosteroid (ICS) response. Interestingly enough, the relationship between COPD and diseases associated with Type2 inflammation from the perspective of impaired lung development is increasingly highlighted by recent epidemiologic studies on the origin of COPD. Therefore, many researchers have shown an interest in the prevalence and the role of existent Type2 biomarkers such as sputum and blood eosinophils, exhaled nitric oxide fraction, and atopy, not only in asthma but also in COPD. Although the evidence about Type2 biomarkers in COPD is inconsistent and less robust, Type2 biomarkers have shown some potential when analyzing various clinical outcomes or therapeutic response to ICS. In this article, we review the existent and emerging Type2 biomarkers with clinically higher applicability in the management of COPD.

Level of serum IL-33 and emphysema paraseptal in clove cigarette smoker with spontaneous pneumothorax: A case report

A young male clove cigarette smoker experienced spontaneous pneumothorax and later paraseptal emphysema was detected on high-resolution computed tomography (HRCT) scan without respiratory symptoms. Smoking is a known risk factor for emphysema. Paraseptal emphysema is a type of emphysema that rarely causes respiratory symptoms, nevertheless, usually accompanied by spontaneous pneumothorax. Interleukin 33 (IL-33) is an alarmin cytokine that belongs to the IL-1 family. The effects of IL-33 depend on its structure. In its mature form, it is a cytokine alarmin that binds to ST2 (suppression of tumorigenicity) receptors on the surface of macrophages and innate immune cells to drive Th1/Th2 immune responses, causing oxidative stress, and increased IL-33 production causes polarization of alveolar macrophages to an M2 phenotype. In this study, long-term exposure to clove cigarette smoke caused an increased serum level of IL-33 (43.72 pg/mL) and paucigranulocytic airway inflammation. In paucigranulocytic inflammation, IL-33 is involved in lung parenchymal damage presumably through oxidative stress, activation of alveolar macrophage and increased MMP12 secretion, resulting in alveolar destruction and airspace enlargement.

Hepatitis B virus X protein (HBx) promotes ST2 expression by GATA2 in liver cells

At present, most studies on the relationship between hepatitis B virus (HBV) and IL-33/ST2 axis focus on clinical detection, but the underlying molecular mechanisms of HBx and IL-33/ST2 axis regulation and Th cell function regulation have not been explored. In this study, serum samples of patients with chronic hepatitis B (CHB) and HBV-related liver cancer (HBV-HCC), and healthy controls, as well as the supernatant solutions of HL7702-WT, HL7702-NC, and HL7702-HBx cells were collected to detect the content of soluble ST2 (sST2). The contents of Th1 cytokines (TNF-α and TNF-γ) and Th2 cytokines (IL-6 and IL-10) in the supernatant of different co-culture groups were detected. The effects of GATA2 on ST2 promoter transcription were investigated by upregulation or interference with GATA2 expression, dual-luciferase reporting, and ChIP experiments. The combined detection of sST2 and FIB-4 was beneficial to the non-invasive diagnosis of liver fibrosis. HBx promotes sST2 expression in liver cells, upregulates Th2 cell function, and inhibits Th1 cell function through IL-33/ST2 axis. HBx interacts with GATA2 to influence the activity of ST2 promoter. Serum sST2 detection is an invaluable indicator for the assessment of the progress of HBV infectious diseases, and the IL-33/ST2 axis plays an important role in changing the cellular immune function caused by HBV infection.

The clinical efficacy of AG NPP709 (Synatura®) in patients with chronic bronchitis type stable chronic obstructive pulmonary disease

Background

AG NPP709 (Synatura^®) has been demonstrated to be efficacious in decreasing cough and sputum in patients with acute upper respiratory infection and chronic inflammatory bronchitis. The aim of this study was to evaluate the efficacy of AG NPP709 in patients with chronic bronchitis type chronic obstructive pulmonary disease (COPD).

Methods

This was a prospective, open-label, single-arm clinical trial (NCT03623282). Chronic bronchitis type COPD patients aged >40 years were enrolled. The primary endpoint was improvement on the CAT scores between the baseline visit and week 12. The secondary endpoints were the effect of AG NPP709 on the pulmonary function and systemic inflammation, as indexed by CRP, fibrinogen, IL-6, TNF-α and IL-33 levels.

Results

Thirty patients were enrolled. All patients were male, and their mean age was 71.93±7.93 years. The mean post-bronchodilator forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC) ratio was 58.63±11.40, and FEV1 (%) was 75.93±20.42. The mean total CAT score was 14.77±7.14. Of these patients, 26 were followed up after 3 months. A significant improvement was observed in the total CAT score (from 14.38±6.62 to 12.73±6.60, P=0.005). Fibrinogen level decreased significantly (P=0.013). No serious adverse events occurred.

Conclusions

AG NPP709 improved the quality of life, as represented by the CAT score, in patients with chronic bronchitis type COPD, and significantly reduced fibrinogen levels. These results suggest that AG NPP709 is efficacious and safe in patients with chronic bronchitis type COPD.

IL-33 in Chronic Respiratory Disease: From Preclinical to Clinical Studies

IL-33 has been deorphanized as a member of the IL-1 family and has key roles as an alarmin and cytokine with potent capacity to drive type 2 inflammation. This has led to a plethora of studies surrounding its role in chronic diseases with a type 2 inflammatory component. Here, we review the roles of IL-33 in two chronic respiratory diseases, asthma and chronic obstructive pulmonary disease (COPD). We discuss the hallmark and paradigm-shifting studies that have contributed to our understanding of IL-33 biology. We cover animal studies that have elucidated the mechanisms of IL-33 and assessed the role of anti-IL-33 treatment and immunization against IL-33. We highlight key clinical evidence for the potential of targeting increased IL-33 in respiratory diseases including exacerbations, and we outline current clinical trials using an anti-IL-33 monoclonal antibody in asthma patients. Finally, we discuss some of the challenges that have arisen in IL-33 biology and highlight potential future directions in targeting this cytokine in chronic respiratory diseases.

Pilot-Scale Study Of Human Plasma Proteomics Identifies ApoE And IL33 As Markers In Atopic Asthma

Background

The pathobiology of atopic asthma is complex and the symptoms similar to other respiratory diseases. As such, identification of biomarkers of atopic asthma is of prime importance for better diagnosis and control of the disease.

Objectives

We sought to study the changes in plasma proteome and cytokine-expression profile across healthy and atopic asthmatics for identifying biomarkers and exploring aberrant pathways for atopic asthma.

Methods

A pilot-scale study in humans was performed to identify differentially expressed proteins in blood plasma of healthy controls (n=5) and treatment-naïve atopic asthma patients (n=5) using quantitative label-free liquid chromatography-tandem mass spectrometry proteomics and ELISA.

Results

Mass spectrometry-based proteomic analysis revealed ApoE to be significantly downregulated in atopic asthmatics compared to healthy volunteers. Decreased expression of ApoE in atopic asthmatics was validated by immunoblotting (50.74% decrease). Comparison with atopic asthmatics and COPD patients showed that ApoE was decreased (36.33%) in atopic asthma compared to COPD. IL33 was significantly upregulated in atopic asthmatics compared to healthy subjects (3.84-fold).

Conclusion

ApoE was downregulated and IL33 upregulated in atopic asthma patients compared to healthy volunteers. These two proteins' profiles were distinct in atopic asthma from healthy and COPD plasma samples. Differential expression of these proteins could serve as a probable candidate for a two-protein classifier-based prognostic biomarker of atopic asthma.

Type 2 innate lymphoid cells participate in IL-33-stimulated Th2-associated immune response in chronic obstructive pulmonary disease

The aim of the present study was to investigate the roles of type 2 innate lymphoid cells (ILC2s) and interleukin-33 (IL-33) in chronic obstructive pulmonary disease (COPD). Serum and peripheral blood mononuclear cells (PBMCs) were isolated from healthy controls and COPD patients. ILC2 cells from the peripheral blood of COPD patients were stimulated with IL-33 or neutralizing ST2 antibody+IL-33 in vitro. The cell viability was assessed using a Cell Counting Kit-8 assay. ELISA was used to detect serum IL-33 and the levels of IL-4, IL-5, IL-6, IL-13 and soluble ST2 (sST2) in the culture supernatant. The percentage of ILC2 cells was measured by flow cytometry. The mRNA expression levels of GATA binding protein 3 (GATA3), RAR-related orphan receptor (ROR)α, ST2 and prostaglandin D2 receptor 2 (CRTH2) were detected by reverse transcription-quantitative PCR. It was revealed that IL-33, IL-5, IL-6 and IL-13 were significantly elevated in peripheral blood of patients with COPD. The proportion of ILC2s in peripheral blood of COPD patients was significantly increased, and the expression of RORA and CRTH2 was increased. The proportion of ST2⁺ ILC2 cells was significantly increased. After 48 h of IL-33 stimulation in vitro, the ratio of linage^-CD45⁺CD127⁺CRTH2⁺ cells reached a maximum. In addition, the viability of ILC2 cells, the expression levels of RORA, GATA3, ST2 and CRTH2 mRNA and the cytokines IL-4, IL-6, IL-5, IL-13 and sST2 were significantly increased. These effects were abrogated by treatment with anti-ST2. In conclusion, IL-33 is upregulated in the serum of patients with COPD and the proportion of ILC2s among the PBMCs is increased. IL-33 may promote the proliferation of ILC2 cells and secrete type 2 T-helper cell cytokines to participate in the immune response in COPD.

Epithelial alarmin levels in exhaled breath condensate in patients with idiopathic pulmonary fibrosis: A pilot study

INTRODUCTION

Interleukin (IL)-25, IL-33 and thymic stromal lymphopoietin (TSLP) are epithelial alarmins involved in innate immune responses and have been shown to play an important role in chronic lung diseases. No data are available regarding their levels in exhaled breath condensate (EBC) in idiopathic pulmonary fibrosis (IPF).

OBJECTIVES

To examine IL-25, IL-33 and TSLP levels in the EBC obtained from patients with IPF and compare them to those in healthy controls, patients with asthma and chronic obstructive pulmonary disease (COPD).

METHODS

Twenty-three patients with asthma, 25 patients with COPD, 15 patients with IPF and 16 healthy controls were studied. Concentrations of alarmins in the EBC were evaluated by means of ELISA.

RESULTS

IL-25 EBC levels were numerically lowest in IPF (25.33 ± 8.84 pg/ml). However, they did not differ significantly from healthy subjects (43.18 ± 5.53 pg/ml), but were significantly lower compared to asthma (72.07 ± 6.03 pg/ml; P < .001). IL-33 EBC levels were significantly increased in IPF (3.41 ± 0.55 pg/ml) compared to healthy controls (1.20 ± 0.60 pg/ml; P < .01) but did not differ from asthma (3.68 pg/ml) and COPD levels (2.47 ± 0.34 pg/ml). There were significant correlations between IL-33 EBC levels and lung diffusion capacity of carbon monoxide (DL_co ) absolute (r = .63; P < .05) and % of predicted values (r = .67; P < .01) as well as with time since diagnosis (r = -.59; P < .05) in IPF subjects. TSLP was undetectable in examined samples.

CONCLUSION

IL-25 and IL-33 are detectable in the EBC obtained from IPF subjects. Increased levels of IL-33 compared to healthy controls indicate its possible role in the pathobiology of IPF.

IL-33 promotes the progression of nonrheumatic aortic valve stenosis via inducing differential phenotypic transition in valvular interstitial cells

OBJECTIVE

Interleukin (IL)-33 is a mediator in the pathogenesis of several inflammatory diseases. Its receptor, ST2, is overexpressed in nonrheumatic aortic valve stenosis (NR-AS). This study compared smooth muscle α-actin (α-SMA), osteopontin (OPN), and suppression of tumorigenicity 2 (ST2) expression between specimens from fibrotic and calcific stages of NR-AS and observed the effects and mechanisms of phenotypic transition of porcine valvular interstitial cells (VICs) in the presence of IL-33.

METHODS

Peripheral blood IL-1 family mRNA and protein levels in NR-AS patients and healthy adults were quantified by real-time quantitative polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay. Immunohistochemistry and immunofluorescence were used to detect the expression and coexpression of α-SMA, OPN, and ST2 in NR-AS specimens. Porcine VICs were stimulated with IL-33, IL-33+SB203580, or IL-33+SC75741. mRNA and protein expression levels of porcine VICs were detected by RT-qPCR and western blot.

RESULTS

The mRNA and protein levels of IL-33 and sST2 in peripheral blood of NR-AS patients were higher than those in healthy adults. Immunohistochemistry and immunofluorescence showed higher expression of α-SMA, OPN, and ST2 in the calcific stage of NR-AS than in the fibrotic stage. Coexpression of ST2/α-SMA or ST2/OPN was found only in the calcific stage. Nuclear factor (NF)-κB and p38 mitogen-activated protein kinase (MAPK) phosphorylation levels were associated with IL-33-induced porcine VIC differentiation into myofibroblasts and osteoblasts, respectively. IL-33 stimulation also promoted the coexpression of ST2/OPN or α-SMA/OPN/ST2.

CONCLUSION

IL-33 might be a potential biomarker for NR-AS. IL-33-induced porcine VIC differential phenotypic transition and differentiation into myofibroblasts and osteoblasts were dependent on the NF-κB and p38 MAPK signaling pathways, respectively.

The association between airway eosinophilic inflammation and IL-33 in stable non-atopic COPD

Background

Interleukin(IL)-33 is an epithelial alarmin important for eosinophil maturation, activation and survival. The aim of this study was to examine the association between IL-33, its receptor expression and airway eosinophilic inflammation in non-atopic COPD.

Methods

IL-33 concentrations were measured in exhaled breath condensate (EBC) collected from healthy non-smokers, asthmatics and non-atopic COPD subjects using ELISA. Serum and sputum samples were collected from healthy non-smokers, healthy smokers and non-atopic COPD patients. Based on sputum eosinophil count, COPD subjects were divided into subgroups with airway eosinophilic inflammation (sputum eosinophils > 3%) or without (sputum eosinophils ≤3%). IL-33 and soluble form of IL-33 receptor (sST2) protein concentrations were measured in serum and sputum supernatants using ELISA. ST2 mRNA expression was measured in peripheral mononuclear cells and sputum cells by qPCR. Hemopoietic progenitor cells (HPC) expressing ST2 and intracellular IL-5 were enumerated in blood and induced sputum by means of flow cytometry.

Results

IL-33 levels in EBC were increased in COPD patients to a similar extent as in asthma and correlated with blood eosinophil count. Furthermore, serum and sputum IL-33 levels were higher in COPD subjects with sputum eosinophilia than in those with a sputum eosinophil count ≤3% (p < 0.001 for both). ST2 mRNA was overexpressed in sputum cells obtained from COPD patients with airway eosinophilic inflammation compared to those without sputum eosinophilia (p < 0.01). Similarly, ST2 + IL-5+ HPC numbers were increased in the sputum of COPD patients with airway eosinophilia (p < 0.001).

Conclusions

Our results indicate that IL-33 is involved in the development of eosinophilic airway inflammation in non-atopic COPD patients.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0807-y) contains supplementary material, which is available to authorized users.

Comparative Study of IL-33 and IL-6 Levels in Different Respiratory Samples in Mild-to-Moderate Asthma and COPD

IL-6 and IL-33 are involved in the inflammatory process in obstructive lung diseases. In contrast to IL-6, few data on the expression of IL-33 in different biological samples from asthma and COPD patients are available. The aim was to evaluate the expressions of IL-33 and IL-6 in bronchial mucosa and to compare these expressions with the concentrations of both cytokines in various respiratory samples from patients with mild-to-moderate asthma and COPD. Serum, induced sputum and exhaled breath condensate IL-6 and IL-33 levels, as well as their expression in bronchial mucosa were evaluated in 22 asthma and 33 COPD patients. There were significant differences between bronchial mucosa IL-6, but not IL-33 expression in asthma and COPD. Serum and IS IL-6 concentrations were higher in COPD than in asthma (3.4 vs. 2.02 pg/mL, p = 0.002 and 16.5 vs. 12.7 pg/mL, p = 0.007, respectively); IL-33 levels reached similar values in asthma and COPD in all investigated samples. In both diseases, the lowest levels of IL-6 and IL-33 were found in EBC. EBC levels of both cytokines did not correlate with their expression in other materials. The IL-33 and IL-6 are detectable in serum, IS and EBC not only in asthma but also in COPD patients. In the COPD group, serum and IS IL-6 concentrations were statistically higher than in the asthma group. The tissue expression of IL-33 and IL-33 concentrations in the investigated biological samples were on a comparable level in both diseases. Our findings may suggest that IL-33 activation is a common pathway in asthma and COPD.

Pathogenesis of thromboangiitis obliterans: Gene polymorphism and immunoregulation of human vascular endothelial cells

Thromboangiitis obliterans (TAO) is a nonatherosclerotic, segmental, inflammatory vasculitis, which commonly affects the small- and medium-sized arteries of the upper and lower extremities. Despite its discovery more than a century ago, little progress has been made in its treatment. Unless the pathogenesis is elucidated, therapeutic approaches will be limited. The purpose of this review article is to collate current knowledge of mechanisms for the pathogenesis of thromboangiitis obliterans and to propose potential mechanisms from a genetic and immunoreactive point of view for its inception. Therefore, we discuss the possibility that the pathogenesis of this disease is due to a type of gene polymorphism, which leads to an immunological inflammatory vasculitis associated with tobacco abuse, highly linked to T cells, human vascular endothelial cells (HVECs), and the TLR-MyD88-NFκB pathway, distinct from arteriosclerosis obliterans and other vasculitides.