Airway inflammation and mannitol challenge test in COPD

Variability of fractional exhaled nitric oxide is associated with the risk and aetiology of COPD exacerbations

BACKGROUND AND OBJECTIVE

Acute exacerbations of chronic obstructive pulmonary disease (AECOPD) are heterogeneous in aetiology and accelerate disease progression. Here, we aimed to investigate the association of fractional exhaled nitric oxide (FeNO) and its variability with AECOPD of different aetiology.

METHODS

FeNO was determined in 2157 visits (1697 stable, 133 AECOPD and 327 follow-up) of 421 COPD patients from the PREVENT study, an investigator-initiated, longitudinal and interventional study, who were on daily treatment with inhaled corticosteroids/long-acting β2-agonists.

RESULTS

Longitudinal measurements of FeNO revealed an intra-subject variability of FeNO that was significantly higher in exacerbators compared to non-exacerbators (p < 0.001) and positively associated with the number of AECOPD. As FeNO variability increased, the probability of patients to remain AECOPD-free decreased. In patients included in the highest FeNO variability quartile (≥15.0 ppb) the probability to remain free of AECOPD was only 35% as compared to 80% for patients included in the lowest FeNO variability quartile (0.50-4.39 ppb). The change of FeNO from the last stable visit to AECOPD was positively associated with the probability of viral infections and this association was stronger in current smokers than ex-smokers. In contrast, the change in FeNO from the last stable visit to an AECOPD visit was inversely associated with the probability of bacterial infections in ex-smokers but not in current smokers.

CONCLUSION

FeNO variability was associated with the risk and aetiology of AECOPD differentially in current and ex-smokers.

Diagnostic value of fractional exhaled nitric oxide in differentiating the asthma-COPD overlap from COPD: a systematic review and meta-analysis

BACKGROUND

Patients with asthma-COPD overlap (ACO) account for 15-20% of chronic obstructive pulmonary disease (COPD), and the incidence increases with age. Patients with ACO have worse outcomes without proper treatment than those with COPD alone. However, the current diagnostic criteria of ACO are mainly based on symptom features and lack of objective indicators. Recently, several studies have demonstrated that fractional exhaled nitric oxide (FeNO) was higher in ACO than in COPD alone. Thus, this study aims to determine the diagnostic value of FeNO in differentiating ACO from COPD and assisting clinical decision-making.

METHODS

We conducted searches in the databases including PubMed, Web of Science, Cochrane Library, and Embase to extract original studies.

RESULTS

In all, 10 studies involving 1335 participants were included in this meta-analysis. FeNO level was significantly higher in ACO patients than in patients with COPD alone (WMD = 11.15ppb, 95%CI = 9.01‒13.28; I² = 18.0%, p = 0.000). The sensitivity and specificity of FeNO in distinguishing ACO from COPD were both 0.71, and the area under the receiver-operating characteristic curve (AUC) was 0.76, indicating that FeNO has moderate diagnostic accuracy in differentiating ACO from COPD.

CONCLUSION

FeNO as an inflammatory biomarker is effective in differentiating ACO from COPD and assisting in clinical decision-making.

Emerging Biological Functions of IL-17A: A New Target in Chronic Obstructive Pulmonary Disease?

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease that causes high rates of disability and mortality worldwide because of severe progressive and irreversible symptoms. During the period of COPD initiation and progression, the immune system triggers the activation of various immune cells, including Regulatory T cells (Tregs), dendritic cells (DCs) and Th17 cells, and also the release of many different cytokines and chemokines, such as IL-17A and TGF-β. In recent years, studies have focused on the role of IL-17A in chronic inflammation process, which was found to play a highly critical role in facilitating COPD. Specially, IL-17A and its downstream regulators are potential therapeutic targets for COPD. We mainly focused on the possibility of IL-17A signaling pathways that involved in the progression of COPD; for instance, how IL-17A promotes airway remodeling in COPD? How IL-17A facilitates neutrophil inflammation in COPD? How IL-17A induces the expression of TSLP to promote the progression of COPD? Whether the mature DCs and Tregs participate in this process and how they cooperate with IL-17A to accelerate the development of COPD? And above associated studies could benefit clinical application of therapeutic targets of the disease. Moreover, four novel efficient therapies targeting IL-17A and other molecules for COPD are also concluded, such as Bufei Yishen formula (BYF), a Traditional Chinese Medicine (TCM), and curcumin, a natural polyphenol extracted from the root of Curcuma longa.

Role of Atypical Chemokines and Chemokine Receptors Pathways in the Pathogenesis of COPD

Chronic obstructive pulmonary disease (COPD) represents a heightened inflammatory response in the lung generally resulting from tobacco smoking-induced recruitment and activation of inflammatory cells and/or activation of lower airway structural cells. Several mediators can modulate activation and recruitment of these cells, particularly those belonging to the chemokines (conventional and atypical) family. There is emerging evidence for complex roles of atypical chemokines and their receptors (such as high mobility group box 1 (HMGB1), antimicrobial peptides, receptor for advanced glycosylation end products (RAGE) or toll-like receptors (TLRs)) in the pathogenesis of COPD, both in the stable disease and during exacerbations. Modulators of these pathways represent potential novel therapies for COPD and many are now in preclinical development. Inhibition of only a single atypical chemokine or receptor may not block inflammatory processes because there is redundancy in this network. However, there are many animal studies that encourage studies for modulating the atypical chemokine network in COPD. Thus, few pharmaceutical companies maintain a significant interest in developing agents that target these molecules as potential antiinflammatory drugs. Antibody-based (biological) and small molecule drug (SMD)-based therapies targeting atypical chemokines and/or their receptors are mostly at the preclinical stage and their progression to clinical trials is eagerly awaited. These agents will most likely enhance our knowledge about the role of atypical chemokines in COPD pathophysiology and thereby improve COPD management.

Targeting eosinophils in respiratory diseases: Biological axis, emerging therapeutics and treatment modalities

Eosinophils are bi-lobed, multi-functional innate immune cells with diverse cell surface receptors that regulate local immune and inflammatory responses. Several inflammatory and infectious diseases are triggered with their build up in the blood and tissues. The mobilization of eosinophils into the lungs is regulated by a cascade of processes guided by Th2 cytokine generating T-cells. Recruitment of eosinophils essentially leads to a characteristic immune response followed by airway hyperresponsiveness and remodeling, which are hallmarks of chronic respiratory diseases. By analysing the dynamic interactions of eosinophils with their extracellular environment, which also involve signaling molecules and tissues, various therapies have been invented and developed to target respiratory diseases. Having entered clinical testing, several eosinophil targeting therapeutic agents have shown much promise and have further bridged the gap between theory and practice. Moreover, researchers now have a clearer understanding of the roles and mechanisms of eosinophils. These factors have successfully assisted molecular biologists to block specific pathways in the growth, migration and activation of eosinophils. The primary purpose of this review is to provide an overview of the eosinophil biology with a special emphasis on potential pharmacotherapeutic targets. The review also summarizes promising eosinophil-targeting agents, along with their mechanisms and rationale for use, including those in developmental pipeline, in clinical trials, or approved for other respiratory disorders.

Asthma and Lung Mechanics

This article will discuss in detail the pathophysiology of asthma from the point of view of lung mechanics. In particular, we will explain how asthma is more than just airflow limitation resulting from airway narrowing but in fact involves multiple consequences of airway narrowing, including ventilation heterogeneity, airway closure, and airway hyperresponsiveness. In addition, the relationship between the airway and surrounding lung parenchyma is thought to be critically important in asthma, especially as related to the response to deep inspiration. Furthermore, dynamic changes in lung mechanics over time may yield important information about asthma stability, as well as potentially provide a window into future disease control. All of these features of mechanical properties of the lung in asthma will be explained by providing evidence from multiple investigative methods, including not only traditional pulmonary function testing but also more sophisticated techniques such as forced oscillation, multiple breath nitrogen washout, and different imaging modalities. Throughout the article, we will link the lung mechanical features of asthma to clinical manifestations of asthma symptoms, severity, and control. © 2020 American Physiological Society. Compr Physiol 10:975-1007, 2020.

Is Inhaled Furosemide a Potential Therapeutic for COVID-19?

The potentially lethal infection caused by the novel Severe Acute Respiratory Disease Coronavirus-2 (SARS-CoV-2) has evolved into a global crisis. Following the initial viral infection is the host inflammatory response that frequently results in excessive secretion of inflammatory cytokines (e.g., IL-6 and TNFα), developing into a self-targeting, toxic "cytokine storm" causing critical pulmonary tissue damage. The need for a therapeutic that is available immediately is growing daily but the de novo development of a vaccine may take years. Therefore, repurposing of approved drugs offers a promising approach to address this urgent need. Inhaled furosemide, a small molecule capable of inhibiting IL-6 and TNFα, may be an agent capable of treating the Coronavirus Disease 2019 cytokine storm in both resource-rich and developing countries. Furosemide is a "repurpose-able" small molecule therapeutics, that is safe, easily synthesized, handled, and stored, and is available in reasonable quantities worldwide.

Usefulness of mannitol challenge testing for diagnosing asthma in everyday clinical practice

Background: The mannitol test is widely used for assessment of airway responsiveness in patients with possible asthma, but our knowledge of the value in everyday clinical practice is limited.Objective: To investigate the diagnostic value of the mannitol test in a clinical setting.Methods: All patients having a mannitol challenge test as part of their diagnostic work-up for asthma at the respiratory outpatient clinic, Hvidovre Hospital, over a 5-year period were included in the present analysis. Case history, including previous diagnoses, spirometry, exhaled nitric oxide (F_ENO) was obtained. The mannitol challenge was performed according to guidelines, i.e. increasing doses of mannitol (from 5 to 635 mg) until maximum dose or a 15% decline in FEV₁ (PD₁₅) was achieved (positive test defined as a PD₁₅ < 635 mg).Results: Our cohort comprised 566 patients (210 men). Post-challenge, 247 patients were diagnosed with asthma by a specialist in respiratory medicine, of whom 138 (56%) had a positive mannitol test. A diagnosis of asthma was ruled out by the specialist in 319 individuals, of whom 18 (6%) had a positive mannitol test and 77 (24%) previous doctor-diagnosed asthma (but with no evidence of a confirmatory test). The specificity and sensitivity of the test was 94% and 56%, respectively. Female gender (p = 0.005), increasing BMI (p < 0.001), exercise-induced cough (p = 0.002), night-time respiratory symptoms (p = 0.002), low FEV₁/FVC ratio (p = 0.008) and high F_ENO (p < 0.001) were determinants for a positive mannitol test.Conclusion: In everyday clinical work-up of patients with possible asthma, the sensitivity and specificity of the mannitol challenge test is comparable to previous controlled trials.

Therapeutic options to treat mustard gas poisoning - Review

Among the blistering (vesicant) chemical warfare agents (CWA), sulfur mustard is the most important since it is known as the "King of chemical warfare agents". The use of sulfur mustard has caused serious damages in several organs, especially the eyes, skin, respiratory, central and peripheral nervous systems after short and long term exposure, incapacitating and even killing people and troops. In this review, chemical properties, mechanism of actions and their effects on each organ, clinical manifestations, diagnostic evaluation of the actions triage, and treatment of injuries have been described.

Persistently elevated exhaled nitric oxide fraction is associated with increased risk of exacerbation in COPD

Preventing the occurrence of acute exacerbations of chronic obstructive pulmonary disease (AECOPD) is a major therapeutic goal. We hypothesise that persistently increased levels of exhaled nitric oxide (F_eNO) during follow-up can identify a group of COPD patients at higher risk of AECOPD.To test this hypothesis, we measured F_eNO levels (HypAir F_eNO®, Medisoft; Sorinnes, Belgium) prospectively in 226 clinically stable COPD outpatients at recruitment and during follow-up (at 6 and 12 months). Patients were stratified according to the number of visits with F_eNO ≥20 ppb.F_eNO was <20 ppb in all three visits in 44.2% of patients, 29.6% in visit 1 and 26.1% in visit 2 or 3. These three groups suffered progressively higher AECOPD rates during follow-up (0.67, 0.91 and 1.42, respectively, p<0.001). After adjusting for potential confounding variables (log-rank test), the hazard ratio for AECOPD was higher in the latter group (1.579 (95% CI 1.049-2.378), p=0.029). Likewise, time to first moderate and severe AECOPD was shorter in these patients. Finally, there was no relationship between F_eNO levels and circulating eosinophils.Persistent F_eNO levels ≥20 ppb in clinically stable COPD outpatients are associated with a significantly higher risk of AECOPD.

Diagnostic performance of the measurement of nitric oxide in exhaled air in the diagnosis of COPD phenotypes

INTRODUCTION

COPD is a highly heterogeneous disease that has a serious impact on affected populations. Patients share some of the features of bronchial asthma, often summarized under the term ACOS (asthma-COPD overlap syndrome). The objective of this study is to evaluate the utility of the measurement of nitric oxide in exhaled air (FENO50) in the diagnosis of COPD phenotypes.

MATERIAL AND METHODS

The study comprised cross-sectional observation of patients receiving assistance during a respiratory outpatient visit. Patient data was collected on lung function, FENO, questionnaires scoring CAT®(COPD Assessment Test), and COPD clinical phenotype.

RESULTS

192 patients were studied: 103 with COPD; 16 healthy non-smokers; 30 healthy smokers; and 43 asthmatics. COPD patients were grouped by phenotype: 34 non exacerbators (33.0%); 22 ACOS (21.3%); 13 frequent exacerbators with emphysema (12.6%); and 34 frequent exacerbators with chronic bronchitis (33.0%). ACOS patients showed significantly higher FENO50 values compared to the others after adjustments for confounding factors. FENO50 demonstrated greater diagnostic accuracy than the bronchodilator test (BT) in the diagnosis of ACOS and COPD phenotypes (AUC 0.79 vs 0.74), with an optimal cut-off value of 19 ppb (sensitivity 0.68, specificity 0.75).

CONCLUSIONS

Patients with COPD have different levels of FENO50 depending on the COPD phenotype. FENO50 measurement provides better diagnostic accuracy than BT, with an optimal cut-off value of 19 ppb.

Bronchial hyperresponsiveness, airway inflammation, and reversibility in patients with chronic obstructive pulmonary disease

BACKGROUND

Bronchial hyperresponsiveness (BHR), sputum eosinophilia, and bronchial reversibility are often thought to be a hallmark of asthma, yet it has been shown to occur in COPD as well.

OBJECTIVES

To evaluate the relationship between BHR, lung function, and airway inflammation in COPD patients.

METHODS

Thirty-one, steroid-free patients with stable, mild and moderate COPD were studied. The following tests were carried out: baseline lung function, reversibility, provocative dose of methacholine causing a 20% fall in forced expiratory volume in 1 second, a COPD symptom score, and sputum induction.

RESULTS

Twenty-nine patients completed the procedures. About 41.4% had BHR, 31.0% had increased sputum eosinophils, and 37.9% had bronchial reversibility. Some of the patients had only one of these characteristics while others had two or the three of them. Patients with BHR had higher sputum eosinophils than patients without BHR (P=0.046) and those with sputum eosinophils ≥3% had more exacerbations in the previous year and a higher COPD symptom score than patients with sputum eosinophils <3% (P=0.019 and P=0.031, respectively). In patients with BHR, the cumulative dose of methacholine was negatively related to the symptom score and the number of exacerbations in the previous year. When patients with bronchial reversibility were considered, bronchodilation was positively related to sputum eosinophils.

CONCLUSION

Our study showed that BHR, sputum eosinophilia, and bronchial reversibility were not clustered in one single phenotype of COPD but could be present alone or together. Of interest, BHR and airway eosinophilia were associated with clinical data in terms of exacerbations and symptoms. Further investigation is needed to clarify this topic.

Response to add-on inhaled corticosteroids in COPD based on airway hyperresponsiveness to mannitol

BACKGROUND

The use of inhaled corticosteroids in mild to moderate COPD is controversial. The aim of this study was to determine whether airway hyperresponsiveness to mannitol might identify patients who are likely to respond to add-on inhaled corticosteroids.

METHODS

Ninety subjects with mild to moderate COPD were recruited and 68 subsequently randomized in a double-blind manner to receive inhaled budesonide (1,600 μg/d, n = 31) or placebo (n = 37) for 3 months. Thirty-eight subjects had airway hyperresponsiveness to mannitol (17 received budesonide, 21 placebo). All subjects received tiotropium throughout the study, including 4 weeks before randomization. Spirometry, quality of life (St. George Respiratory Questionnaire), degree of dyspnea, airway responsiveness to mannitol, and exhaled nitric oxide were assessed at week 0 (recruitment), week 4 (baseline prior to randomization), and week 16 (posttreatment).

RESULTS

Compared with placebo, budesonide was associated with improved quality of life in subjects showing airway hyperresponsiveness to mannitol (difference of changes in quality of life score between randomization and study completion, −9.1; 95% CI, −15.8 to −2.3; P < .01). Treatment with inhaled budesonide also led to a reduction in airway responsiveness to mannitol compared with placebo (difference in log10 response-dose ratio, −0.3; 95% CI, −0.6 to −0.04; P < .01). However, postrandomization changes in FEV1 % predicted, quality of life, and exhaled nitric oxide showed no difference between budesonide and placebo.

CONCLUSIONS

In subjects with mild to moderate COPD and airway hyperresponsiveness to mannitol, quality of life and airway responsiveness improved after treatment with inhaled corticosteroids added to long-acting bronchodilator therapy.

Phenotyping airways disease: an A to E approach

The airway diseases asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous conditions with overlapping pathophysiological and clinical features. It has previously been proposed that this heterogeneity may be characterized in terms of five relatively independent domains labelled from A to E, namely airway hyperresponsiveness (AHR), bronchitis, cough reflex hypersensitivity, damage to the airways and surrounding lung parenchyma, and extrapulmonary factors. Airway hyperresponsiveness occurs in both asthma and COPD, accounting for variable day to day symptoms, although the mechanisms most likely differ between the two conditions. Bronchitis, or airway inflammation, may be predominantly eosinophilic or neutrophilic, with different treatments required for each. Cough reflex hypersensitivity is thought to underlie the chronic dry cough out of proportion to other symptoms that can occur in association with airways disease. Structural changes associated with airway disease (damage) include bronchial wall thickening, airway smooth muscle hypertrophy, bronchiectasis and emphysema. Finally, a variety of extrapulmonary factors may impact upon airway disease, including rhinosinusitis, gastroesophageal reflux disease, obesity and dysfunctional breathing. This article discusses the A to E concept in detail and describes how this framework may be used to assess and treat patients with airway diseases in the clinic.

Airway responsiveness to adenosine after a single dose of fluticasone propionate discriminates asthma from COPD

BACKGROUND

Regular treatment with inhaled corticosteroids (ICS) is known to reduce airway hyperresponsiveness (AHR) to adenosine 5'-monophosphate (AMP) in asthma even after a single dose of fluticasone propionate (FP).

AIM

To determine whether this rapid protective effect of a single dose of FP is also present in COPD.

METHODS

23 mild asthmatic and 24 COPD subjects with documented AHR to both AMP and methacholine took part in a randomized, double-blind, placebo-controlled, crossover study to measure AHR to inhaled AMP and methacholine 2 h after either 1000 μg FP or matched placebo.

RESULTS

In subjects with asthma, 1000 μg FP in a single dose significantly attenuated the constrictor response to AMP, geometric mean (range) PC20AMP values increasing from a 19.2 (1.3-116.3) to 81.5 (9.6-1600.0) (p < 0.001; post-placebo vs post-FP) mg/ml. Change in the airways response to inhaled AMP after FP was well within test variability in patients with COPD, with PC20AMP values 59.6 (11.3-183.9) and 76.3 (21.0-445.3) (p = 0.022; post-placebo vs post-FP) mg/ml. Additionally, FP failed to significantly attenuate the bronchial response to methacholine in both asthma and COPD subjects. A change in doubling dilution, between placebo and following a single dose of FP, in AMP had a better sensitivity and specificity of 95.8% and 65.2%, compared to methacholine of 79.2% and 43.5% respectively in delineating between COPD and asthma.

CONCLUSION

A single dose of 1000 μg FP rapidly improves AHR to AMP in asthmatics but not in COPD subjects. This may provide a convenient way by which provocation challenge with inhaled AMP may help in discriminating asthma from COPD.

Treatment for sulfur mustard lung injuries; new therapeutic approaches from acute to chronic phase

Objective

Sulfur mustard (SM) is one of the major potent chemical warfare and attractive weapons for terrorists. It has caused deaths to hundreds of thousands of victims in World War I and more recently during the Iran-Iraq war (1980–1988). It has ability to develop severe acute and chronic damage to the respiratory tract, eyes and skin. Understanding the acute and chronic biologic consequences of SM exposure may be quite essential for developing efficient prophylactic/therapeutic measures. One of the systems majorly affected by SM is the respiratory tract that numerous clinical studies have detailed processes of injury, diagnosis and treatments of lung. The low mortality rate has been contributed to high prevalence of victims and high lifetime morbidity burden. However, there are no curative modalities available in such patients. In this review, we collected and discussed the related articles on the preventive and therapeutic approaches to SM-induced respiratory injury and summarized what is currently known about the management and therapeutic strategies of acute and long-term consequences of SM lung injuries.

Method

This review was done by reviewing all papers found by searching following key words sulfur mustard; lung; chronic; acute; COPD; treatment.

Results

Mustard lung has an ongoing pathological process and is active disorder even years after exposure to SM. Different drug classes have been studied, nevertheless there are no curative modalities for mustard lung.

Conclusion

Complementary studies on one hand regarding pharmacokinetic of drugs and molecular investigations are mandatory to obtain more effective treatments.