Neutrophil Elastase Activity Is Associated with Exacerbations and Lung Function Decline in Bronchiectasis

Evolution of NETosis markers and DAMPs have prognostic value in critically ill COVID-19 patients

Coronavirus disease 19 (COVID-19) presents with disease severities of varying degree. In its most severe form, infection may lead to respiratory failure and multi-organ dysfunction. Here we study the levels and evolution of the damage associated molecular patterns (DAMPS) cell free DNA (cfDNA), extracellular histone H3 (H3) and neutrophil elastase (NE), and the immune modulators GAS6 and AXL in relation to clinical parameters, ICU scoring systems and mortality in patients (n = 100) with severe COVID-19. cfDNA, H3, NE, GAS6 and AXL were increased in COVID-19 patients compared to controls. These measures associated with occurrence of clinical events and intensive care unit acquired weakness (ICUAW). cfDNA and GAS6 decreased in time in patients surviving to 30 days post ICU admission. A decrease of 27.2 ng/mL cfDNA during ICU stay associated with patient survival, whereas levels of GAS6 decreasing more than 4.0 ng/mL associated with survival. The presence of H3 in plasma was a common feature of COVID-19 patients, detected in 38% of the patients at ICU admission. NETosis markers cfDNA, H3 and NE correlated well with parameters of tissue damage and neutrophil counts. Furthermore, cfDNA correlated with lowest p/f ratio and a lowering in cfDNA was observed in patients with ventilator-free days.

Neutrophil Elastase and Chronic Lung Disease

Neutrophil elastase (NE) is a major inflammatory protease released by neutrophils and is present in the airways of patients with cystic fibrosis (CF), chronic obstructive pulmonary disease, non-CF bronchiectasis, and bronchopulmonary dysplasia. Although NE facilitates leukocyte transmigration to the site of infection and is required for clearance of Gram-negative bacteria, it also activates inflammation when released into the airway milieu in chronic inflammatory airway diseases. NE exposure induces airway remodeling with increased mucin expression and secretion and impaired ciliary motility. NE interrupts epithelial repair by promoting cellular apoptosis and senescence and it activates inflammation directly by increasing cytokine expression and release, and indirectly by triggering extracellular trap release and exosome release, which magnify protease activity and inflammation in the airway. NE inhibits innate immune function by digesting opsonins and opsonin receptors, degrading innate immune proteins such as lactoferrin, and inhibiting macrophage phagocytosis. Importantly, NE-directed therapies have not yet been effective in preventing the pathologic sequelae of NE exposure, but new therapies are being developed that offer both direct antiprotease activity and multifunctional anti-inflammatory properties.

Bronchiectasis Exacerbations: Definitions, Causes, and Acute Management

Pulmonary exacerbations (PExs) are events in the course of bronchiectasis which are defined as an increase in disease symptoms lasting a period of a few days. It is established that the tendency toward having PEx is stable throughout the course of the disease. Certain conditions were found to be associated with an increased risk of developing a PEx. Among these are chronic airway infection with Pseudomonas aeruginosa or Aspergillus species, concomitant airway diseases (asthma, chronic obstructive pulmonary disease, and chronic rhinosinusitis), genetic factors such as primary ciliary dyskinesia, and nutritional factors. The immediate events underlying the onset of a PEx are less clearly determined. Although acute changes in bacterial airway composition have been the paradigm for decades, recent microbiome-focused research has not uniformly established such acute changes at the onset of PEx. Other acute changes such as air pollution, viral infection, and changes in bacterial metabolic activity have also been implicated as causes of a PEx. Despite these gaps in our knowledge of the biology of PEx, antimicrobial therapy directed against the identified pathogens in sputum is currently the recommended therapeutic strategy. Various long-term therapies, including antimicrobial and anti-inflammatory strategies, have been proven effective in reducing the frequency of PEx, leading to a recommendation for the use of these strategies in people with frequent PEx.

Pseudomonas aeruginosa in Bronchiectasis

Pseudomonas aeruginosa (PA) in patients with bronchiectasis (BE) is associated with a poor outcome and quality of life, and its presence is considered a marker of disease severity. This opportunistic pathogen is known for its ability to produce biofilms on biotic or abiotic surfaces and to survive environmental stress exerted by antimicrobials, inflammation, and nutrient or oxygen depletion. The presence of PA biofilms has been linked to chronic respiratory infection in cystic fibrosis but not in BE. There is considerable inconsistency in the reported infection/eradication rates of PA and chronic PA. In addition, inadequate antimicrobial treatment may potentiate the progression from intermittent to chronic infection and also the emergence of antibiotic resistance. A better comprehension of the pathophysiology of PA infections and its implications for BE is urgently needed. This can drive improvements in diagnostic accuracy, can move us toward a new consensus definition of chronic infection, can better define the follow-up of patients at risk of PA, and can achieve more successful eradication rates. In addition, the new technological advances regarding molecular diagnostics, -omics, and biomarkers require us to reconsider our traditional concepts.

Pathophysiology of Bronchiectasis

Bronchiectasis is a complex, heterogeneous disorder defined by both a radiological abnormality of permanent bronchial dilatation and a clinical syndrome. There are multiple underlying causes including severe infections, mycobacterial disease, autoimmune conditions, hypersensitivity disorders, and genetic conditions. The pathophysiology of disease is understood in terms of interdependent concepts of chronic infection, inflammation, impaired mucociliary clearance, and structural lung damage. Neutrophilic inflammation is characteristic of the disease, with elevated levels of harmful proteases such as neutrophil elastase associated with worse outcomes. Recent data show that neutrophil extracellular trap formation may be the key mechanism leading to protease release and severe bronchiectasis. Despite the dominant of neutrophilic disease, eosinophilic subtypes are recognized and may require specific treatments. Neutrophilic inflammation is associated with elevated bacterial loads and chronic infection with organisms such as Pseudomonas aeruginosa. Loss of diversity of the normal lung microbiota and dominance of proteobacteria such as Pseudomonas and Haemophilus are features of severe bronchiectasis and link to poor outcomes. Ciliary dysfunction is also a key feature, exemplified by the rare genetic syndrome of primary ciliary dyskinesia. Mucus symptoms arise through goblet cell hyperplasia and metaplasia and reduced ciliary function through dyskinesia and loss of ciliated cells. The contribution of chronic inflammation, infection, and mucus obstruction leads to progressive structural lung damage. The heterogeneity of the disease is the most challenging aspect of management. An understanding of the pathophysiology of disease and their biomarkers can help to guide personalized medicine approaches utilizing the concept of "treatable traits."

Aspergillus-Associated Endophenotypes in Bronchiectasis

Bronchiectasis is a chronic condition of global relevance resulting in permanent and irreversible structural airway damage. Bacterial infection in bronchiectasis is well studied; however, recent molecular studies identify fungi as important pathogens, either independently or in association with bacteria. Aspergillus species are established fungal pathogens in cystic fibrosis and their role is now increasingly being recognized in noncystic fibrosis bronchiectasis. While the healthy airway is constantly exposed to ubiquitously present Aspergillus conidia in the environment, anatomically damaged airways appear more prone to colonization and subsequent infection by this fungal group. Aspergilli possess diverse immunopathological mechanistic capabilities and when coupled with innate immune defects in a susceptible host, such as that observed in bronchiectasis, it may promote a range of clinical manifestations including sensitization, allergic bronchopulmonary aspergillosis, Aspergillus bronchitis, and/or invasive aspergillosis. How such clinical states influence "endophenotypes" in bronchiectasis is therefore of importance, as each Aspergillus-associated disease state has overlapping features with bronchiectasis itself, and can evolve, depending on underlying host immunity from one type into another. Concurrent Aspergillus infection complicates the clinical course and exacerbations in bronchiectasis and therefore dedicated research to better understand the Aspergillus-host interaction in the bronchiectasis airway is now warranted.

Airway Clearance and Mucoactive Therapies

The respiratory system is constantly exposed to external pathogens but has different and effective defense systems. The pathophysiology of bronchiectasis affects the defense system considerably in that alterations occur in the airway that reduce its effectiveness in mucociliary clearance and the greater presence of mucins leads to the accumulation of more adherent and viscous mucus. One of the pillars of treatment of this disease should be improvement of mucociliary clearance and a decrease in the adherence and viscosity of the mucus. To this end, the mobilization of secretions must be increased through effective respiratory physiotherapy techniques, which can be manual and/or instrumental. The properties of mucus can be modified to improve its mobilization through the use of a mucoactive agent. Despite the increase in the number and quality of studies, the evidence for these treatments remains scarce, although their application is recommended in all guidelines.

T2-High Endotype and Response to Biological Treatments in Patients with Bronchiectasis

Although bronchiectasis pathophysiology has been historically understood around the presence of airway neutrophilic inflammation, recent experiences are consistent with the identification of a type 2 inflammation (T2) high endotype in bronchiectasis. In order to evaluate prevalence and clinical characteristics of bronchiectasis patients with a T2-high endotype and explore their response to biologicals, two studies were carried out. In a cross-sectional study, bronchiectasis adults without asthma underwent clinical, radiological, and microbiological assessment, along with blood eosinophils and oral fractional exhaled nitric oxide (FeNO) evaluation, during stable state. Prevalence and characteristics of patients with a T2- high endotype (defined by the presence of either eosinophils blood count ≥300 cells·µL⁻¹ or oral FeNO ≥ 25 dpp) were reported. A case series of severe asthmatic patients with concomitant bronchiectasis treated with either mepolizumab or benralizumab was evaluated, and patients’ clinical data pre- and post-treatment were analyzed up to 2 years of follow up. Among bronchiectasis patients without asthma enrolled in the cross-sectional study, a T2-high endotype was present in 31% of them. These patients exhibited a more severe disease, high dyspnea severity, low respiratory function, and high impact on quality of life. Among the five patients with severe eosinophilic asthma and concomitant bronchiectasis included in the series, treatment with either mepolizumab or benralizumab significantly reduced the exacerbation rate with an effect that persists for up to 2 years of follow up. If validated across different settings, our data suggest the need to design randomized controlled trials on biological treatments targeting the T2-high endotype in bronchiectasis patients.

Sputum and Plasma Neutrophil Elastase in Stable Adult Patients With Cystic Fibrosis in Relation to Chronic Pseudomonas Aeruginosa Colonization

Background and purpose

Neutrophil elastase (NE) has been implicated in the pathogenesis of airway inflammation in cystic fibrosis (CF) patients and it impairs defenses against Pseudomonas aeruginosa (PA) infection or colonization. Sputum NE may act as a biomarker of neutrophilic inflammation in CF patients. This study aimed to determine sputum and plasma total NE levels in clinically stable adult CF patients and control subjects, and their correlation to PA colonization and lung functions.

Methods

This is a cross-sectional study. Total NE was measured on spontaneously expectorated sputum and plasma obtained from 21 CF patients, aged 18-40 years, during routine visits to the adult CF clinic. This was compared to plasma obtained from 22 matching healthy controls. The levels of NE were measured by the magnetic bead-based multiplex assay.

Results

Sputum and plasma NE levels had a significant positive correlation (Pearson r=0.533, P=0.013) with PA colonization. Sixteen CF patients (76.2%) were chronically colonized with PA. Both median sputum and plasma NE were found to be higher in CF patients with PA as compared with non-PA patients, even though this difference was statistically insignificant. Sputum and plasma NE levels did not correlate with the percentage predicted forced expiratory volume in one second (FEV1), the forced vital capacity (FVC), and FEV1/FVC and no association with PA.

Conclusion

The findings suggest that clinically stable adult CF patients colonized with PA may have higher NE levels in both plasma and sputum as compared to non-PA CF patients and probably total NE does not influence lung functions.

Small Airway Disease and Emphysema Are Associated with Future Exacerbations in Smokers with CT-derived Bronchiectasis and COPD: Results from the COPDGene Cohort

Background Chronic obstructive pulmonary disease (COPD) and bronchiectasis can overlap and share pathologic features, such as small airway disease (SAD). Whether the presence of SAD and emphysema in smokers with CT-derived bronchiectasis is associated with exacerbations is unknown. Purpose To assess whether SAD and emphysema in smokers with CT-derived bronchiectasis are associated with future exacerbations. Materials and Methods SAD and emphysema were quantified using the parametric response map method in former and current heavy smokers with and without bronchiectasis at CT from the COPDGene Study (from July 2009 to July 2018). Exacerbations were prospectively assessed through biannual follow-up. An exacerbation was defined as an increase in or new onset of respiratory symptoms treated with antibiotics and/or corticosteroids. Severe exacerbations were defined as those that required hospitalization. The association of a high burden of SAD (≥15.6%) and high burden of emphysema (≥5%) at CT with exacerbations was assessed with generalized linear mixed models. Results Of 737 participants, 387 (median age, 64 years [interquartile range, 58-71 years]; 223 women) had CT-derived bronchiectasis. During a 9-year follow-up, after adjustment for age, sex, race, body mass index, current smoking status, pack-years, exacerbations before study entry, forced expiratory volume in 1 second, or FEV₁, and bronchiectasis severity CT score, high burden of SAD and high burden of emphysema were associated with a higher number of exacerbations per year (relative risk [RR], 1.89 [95% CI: 1.54, 2.33] and 1.37 [95% CI: 1.13, 1.66], respectively; P ≤ .001 for both). Results were comparable among participants with bronchiectasis meeting criteria for COPD (n = 197) (RR, 1.67 [95% CI: 1.23, 2.27] for high burden of SAD and 1.51 [95% CI: 1.20, 1.91] for high burden of emphysema; P ≤ .001 for both). Conclusion In smokers with CT-derived bronchiectasis and chronic obstructive pulmonary disease, structural damage to lung parenchyma and small airways was associated with a higher number of exacerbations per year. Clinical trial registration no. NCT00608764 © RSNA, 2021.

Serum hepatocyte growth factor as a predictor of disease severity and future exacerbations in patients with non-cystic fibrosis bronchiectasis

BACKGROUND

Serum biomarkers associated with the severity of non-cystic fibrosis (CF) bronchiectasis are insufficient. This study determined the association of serum hepatocyte growth factor (HGF), osteopontin, and pentraxin-3 levels with disease severity and exacerbation in patients with non-CF bronchiectasis.

METHODS

Serum levels of HGF, osteopontin, and pentraxin-3 were measured in patients with clinically stable non-CF bronchiectasis (n = 61). The correlation between the biomarkers and bronchiectasis severity index (BSI) and FACED score was assessed using univariate and multivariate linear regression analyses. Predictive variables associated with exacerbation were analyzed using a Cox proportional hazards model and the time to first exacerbation in high and low HGF groups during the observation period was compared using Kaplan-Meier survival curves.

RESULTS

The BSI showed significant correlation with HGF (r = 0.423; p = 0.001) and pentraxin-3 (r = 0.316; p = 0.013). The FACED score was significantly correlated with HGF (r = 0.406; p = 0.001). Univariate and multivariate linear regression analysis revealed that serum level of HGF was independently associated with both scoring systems. The high HGF group showed a significantly shorter time to first exacerbation (Log-rank test, p = 0.014). Multivariate Cox proportional hazards regression analysis revealed that high serum HGF level and colonization with non-pseudomonas organisms were independent predictors of future exacerbations (HR 2.364; p = 0.024 and HR 2.438; p = 0.020, respectively).

CONCLUSION

Serum level of HGF is a potential biomarker that is closely associated with disease severity and future risk of exacerbations in patients with non-CF bronchiectasis.

Prognostic utility of various multidimensional grading scales among Saudi patients with bronchiectasis

INTRODUCTION

A number of multidimensional scoring systems, including the Bronchiectasis Severity Index (BSI), the FACED score, and the Exacerbation-FACED (Exa-FACED, a derivative of FACED), have been proposed and validated to assess the severity and prognosis in patients with bronchiectasis. Although these metrics have been validated through large multicenter efforts in Europe and Latin America, there have been no attempts at external validation in other populations.

OJECTIVES

The aim of this study was to validate specific multidimensional grading scales (BSI, FACED, and Exa-FACED) in predicting mortality, future exacerbations, and hospitalizations among Saudi patients with bronchiectasis.

METHODS

A prospective observational cohort study was conducted at a tertiary care centre. The three multidimensional grading scales (BSI, FACED, and Exa-FACED) were calculated for each patient. Future frequent acute exacerbations (≥2/year) and severe acute exacerbations leading to hospitalization were recorded for 1 year, and all-cause mortality was monitored for up to 5 years.

RESULTS

A total of 301 patients with bronchiectasis (mean age of 60±17 years and 66% female) were include. All Grading scales performed well in predicting 5-year survival. Area under the curve (AUC) values for BSI (0.86, 95% CI: 0.82-0.90), FACED (0.81, 95% CI: 0.76-0.85), and Ex-FACED (0.83, 95% CI: 0.78-0.87). The BSI (AUC=0.98, 95% CI: 0.96-0.99) performed better than FACED scoring (AUC=0.77, 95% CI: 0.71-0.81; P<0.0001) in predicting hospitalization. Exa-FACED scoring (AUC=0.84, 95% CI: 0.80-0.88) improved upon FACED scores in predicting hospitalization. The BSI (AUC=0.95, 95% CI: 0.91-0.97) fared significantly better than FACED scoring (AUC=0.76, 95% CI: 0.70-0.80; p<0.0001) in predicting frequent acute exacerbations (≥2/year). Again, Exa-FACED scoring (AUC=0.85, 95% CI: 0.81-0.89) improved upon FACED scores in predicting frequent acute exacerbations (≥2/year).

CONCLUSIONS

All scoring systems performed adequately in 5-year mortality projections. Although Exa-FACED scoring improved upon FACED scores in predicting forthcoming frequent acute exacerbations and hospitalization, the BSI outperformed both in this regard.

Protease-Antiprotease Imbalance in Bronchiectasis

Airway inflammation plays a central role in bronchiectasis. Protease-antiprotease balance is crucial in bronchiectasis pathophysiology and increased presence of unopposed proteases activity may contribute to bronchiectasis onset and progression. Proteases' over-reactivity and antiprotease deficiency may have a role in increasing inflammation in bronchiectasis airways and may lead to extracellular matrix degradation and tissue damage. Imbalances in serine proteases and matrix-metallo proteinases (MMPs) have been associated to bronchiectasis. Active neutrophil elastase has been associated with disease severity and poor long-term outcomes in this disease. Moreover, high levels of MMPs have been associated with radiological and disease severity. Finally, severe deficiency of α1-antitrypsin (AAT), as PiSZ and PiZZ (proteinase inhibitor SZ and ZZ) phenotype, have been associated with bronchiectasis development. Several treatments are under study to reduce protease activity in lungs. Molecules to inhibit neutrophil elastase activity have been developed in both oral or inhaled form, along with compounds inhibiting dipeptydil-peptidase 1, enzyme responsible for the activation of serine proteases. Finally, supplementation with AAT is in use for patients with severe deficiency. The identification of different targets of therapy within the protease-antiprotease balance contributes to a precision medicine approach in bronchiectasis and eventually interrupts and disrupts the vicious vortex which characterizes the disease.

Neutrophil extracellular trap-associated molecules: a review on their immunophysiological and inflammatory roles

Neutrophil extracellular traps (NETs) are a defense mechanism against pathogens. They are composed of DNA and various proteins and have the ability to hinder microbial spreading and survival. However, NETs are not only related to infections but also participate in sterile inflammatory events. In addition to DNA, NETs contain histones, serine proteases, cytoskeletal proteins and antimicrobial peptides, all of which have immunomodulatory properties that can augment or decrease the inflammatory response. Extracellular localization of these molecules alerts the immune system of cellular damage, which is triggered by recognition of damage-associated molecular patterns (DAMPs) through specific pattern recognition receptors. However, not all of these molecules are DAMPs and may have other immunophysiological properties in the extracellular space. The release of NETs can lead to production of pro-inflammatory cytokines (due to TLR2/4/9 and inflammasome activation), the destruction of the extracellular matrix, activation of serine proteases and of matrix metallopeptidases (MMPs), modulation of cellular proliferation, induction of cellular migration and adhesion, promotion of thrombogenesis and angiogenesis and disruption of epithelial and endothelial permeability. Understanding the dynamics of NET-associated molecules, either individually or synergically, will help to unravel their role in inflammatory events and open novel perspectives for potential therapeutic targets. We here review molecules contained within NETS and their immunophysiological roles.

The sputum microbiome and clinical outcomes in patients with bronchiectasis: a prospective observational study

BACKGROUND

Infection is a key component of bronchiectasis pathophysiology. Characterisation of the microbiome offers a higher degree of sensitivity and resolution than does traditional culture methods. We aimed to evaluate the role of the microbiome in determining the risk of exacerbation and long-term outcomes, including all-cause mortality, in bronchiectasis.

METHODS

We did a prospective observational cohort study of patients with bronchiectasis from eastern Scotland. Patients were enrolled from Sept 11, 2012, to Dec 21, 2015, and followed until Jan 8, 2019, for long-term outcomes. Patients were included if they were aged 18 years or older, and had a high-resolution CT-confirmed diagnosis of bronchiectasis and clinical symptoms consistent with the disease. Sputum samples were obtained when patients were clinically stable. Repeat sputum samples were taken at stable and exacerbation visits during follow-up. The V3-V4 region of the bacterial 16S rRNA gene was sequenced using the Illumina MiSeq platform. The dominant bacterial genus in each sample was assigned on the basis of a previously published method. Microbiome characteristics were analysed for their association with measures of clinical disease severity and long-term outcomes using PERMANOVA, random forest, and survival analyses.

FINDINGS

Sequencing data were obtained from the sputum samples of 281 patients with bronchiectasis who were included in the stable baseline cohort. 49 (17%) of 281 patients provided more than one sample when clinically stable and were included in the longitudinal analysis. 64 (23%) patients provided both stable and exacerbation samples. In both stable bronchiectasis and during exacerbations, a sputum microbiome dominated by Proteobacteria and Firmicutes was observed. Individual patients' microbiome profiles were relatively stable over time, during exacerbations and at disease stability. Lower microbiome diversity, measured using the Shannon-Wiener diversity index, was associated with more severe bronchiectasis defined by the bronchiectasis severity index, lower FEV₁, and more severe symptoms. Random forest analysis of baseline samples identified Pseudomonas, Enterobacteriaceae, and Stenotrophomonas as being associated with severe bronchiectasis (bronchiectasis severity index ≥9) and greater lung inflammation and Pseudomonas and Enterobacteriaceae with more frequent exacerbations. Patients in whom Pseudomonas was dominant (n=35) were at increased risk of all-cause mortality (hazard ratio 3·12, 95% CI 1·33-7·36; p=0·0091) and had more frequent exacerbations (incident rate ratio 1·69, 95% CI 1·07-2·67; p=0·024) during follow-up compared with patients with other dominant genera (n=246).

INTERPRETATION

A reduction in microbiome diversity, particularly one associated with dominance of Pseudomonas, is associated with greater disease severity, higher frequency and severity of exacerbations, and higher risk of mortality. The microbiome might therefore identify subgroups of patients at increased risk of poor outcomes who could benefit from precision treatment strategies. Further research is required to identify the mechanisms of reduced microbiome diversity and to establish whether the microbiome can be therapeutically targeted.

FUNDING

British Lung Foundation and European Respiratory Society EMBARC2 consortium.

Association between Cardiorespiratory Fitness and Bronchiectasis at CT: A Long-term Population-based Study of Healthy Young Adults Aged 18-30 Years in the CARDIA Study

Background Protective factors against the risk of bronchiectasis are unknown. A high level of cardiorespiratory fitness is associated with a lower risk of chronic obstructive pulmonary disease. But whether fitness relates to bronchiectasis remains, to the knowledge of the authors, unknown. Purpose To examine the association between cardiorespiratory fitness and bronchiectasis. Materials and Methods This was a secondary analysis of a prospective observational study: the Coronary Artery Risk Development in Young Adults cohort (from 1985-1986 [year 0] to 2015-2016 [year 30]). During a 30-year period, healthy participants (age at enrollment 18-30 years) underwent treadmill exercise testing at year 0 and year 20 visits. Cardiorespiratory fitness was determined according to the treadmill exercise duration. The 20-year difference in cardiorespiratory fitness was used as the fitness measurement. At year 25, chest CT was performed to assess bronchiectasis and was used as the primary outcome. Multivariable logistic models were performed to determine the association between cardiorespiratory fitness changes and bronchiectasis. Results Of 2177 selected participants (at year 0: mean age, 25 years ± 4 [standard deviation]; 1224 women), 209 (9.6%) had bronchiectasis at year 25. After adjusting for age, race-sex group, study site, body mass index, pack-years smoked, history of tuberculosis, pneumonia, asthma and myocardial infarction, peak lung function, and cardiorespiratory fitness at baseline, preservation of cardiorespiratory fitness was associated with lower odds of bronchiectasis at CT at year 25 (per 1-minute-longer treadmill duration from year 0 to year 20: odds ratio [OR], 0.88; 95% CI: 0.80, 0.98; P = .02). A consistent strong association was found when cough and phlegm were included in bronchiectasis (OR, 0.72; 95% CI: 0.59, 0.87; P < .001). Conclusion In a long-term follow-up, the preservation of cardiorespiratory fitness was associated with lower odds of bronchiectasis at CT. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Stojanovska in this issue.

ERS International Congress 2020: highlights from the Respiratory Infections assembly

In the coronavirus disease 2019 (COVID-19) pandemic year 2020, the 30th European Respiratory Society (ERS) International Congress took place for the first time in a fully virtual format. Despite the challenging nature of the task to create and deliver an online event of this size and scope, it turned out to be a great success, welcoming over 33 000 delegates to the specially designed online platform and offering more than 450 scientific and educational sessions. Somewhat predictably, this year's ERS International Congress dedicated a full day to the topic of COVID-19, highlighting that infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a respiratory disease that is particularly important this year. In this article, the Early Career Members of the Assembly 10 (Respiratory Infections and Tuberculosis) review some of the most interesting sessions including presentations and posters on respiratory infections and tuberculosis that were deemed as important.

This is a comprehensive summary of several interesting sessions from #ERSCongress 2020 including presentations and posters on respiratory infections and tuberculosis that were deemed as importanthttps://bit.ly/2OtrYXH

Antimicrobial Resistance in Common Respiratory Pathogens of Chronic Bronchiectasis Patients: A Literature Review

Non-cystic fibrosis bronchiectasis is a chronic disorder in which immune system dysregulation and impaired airway clearance cause mucus accumulation and consequent increased susceptibility to lung infections. The presence of pathogens in the lower respiratory tract causes a vicious circle resulting in impaired mucociliary function, bronchial inflammation, and progressive lung injury. In current guidelines, antibiotic therapy has a key role in bronchiectasis management to treat acute exacerbations and chronic infection and to eradicate bacterial colonization. Contrastingly, antimicrobial resistance, with the risk of multidrug-resistant pathogen development, causes nowadays great concern. The aim of this literature review was to assess the role of antibiotic therapy in bronchiectasis patient management and possible concerns regarding antimicrobial resistance based on current evidence. The authors of this review stress the need to expand research regarding bronchiectasis with the aim to assess measures to reduce the rate of antimicrobial resistance worldwide.

Respiratory Mycoses in COPD and Bronchiectasis

Chronic obstructive pulmonary disease (COPD) and bronchiectasis represent chronic airway diseases associated with significant morbidity and mortality. Bacteria and viruses are commonly implicated in acute exacerbations; however the significance of fungi in these airways remains poorly defined. While COPD and bronchiectasis remain recognized risk factors for the occurrence of Aspergillus-associated disease including chronic and invasive aspergillosis, underlying mechanisms that lead to the progression from colonization to invasive disease remain uncertain. Nonetheless, advances in molecular technologies have improved our detection, identification and understanding of resident fungi characterizing these airways. Mycobiome sequencing has revealed the complex varied and myriad profile of airway fungi in COPD and bronchiectasis, including their association with disease presentation, progression, and mortality. In this review, we outline the emerging evidence for the clinical importance of fungi in COPD and bronchiectasis, available diagnostic modalities, mycobiome sequencing approaches and association with clinical outcomes.

Personalized approaches to bronchiectasis

Introduction: Interest in bronchiectasis is increasing due to its rising prevalence, associated with aging populations and the extended use of high-resolution chest tomography (HRCT), and the resulting high morbidity, mortality, and demand for resources.Areas covered: This article provides an extensive review of bronchiectasis as a complex and heterogeneous disease, as well as examining the difficulty of establishing useful clinical phenotypes. In keeping with the aims of 'precision medicine', we address the disease of bronchiectasis from three specific perspectives: severity, activity, and impact. We used PubMed to search the literature for articles including the following keywords: personalized medicine, bronchiectasis, biomarkers, phenotypes, precision medicine, treatable traits. We reviewed the most relevant articles published over the last 5 years.Expert opinion: This article reflects on the usefulness of these three dimensions in 'control panels' and clinical fingerprinting, as well as approaches to personalized medicine and the treatable features of bronchiectasis non-cystic fibrosis.

Paired CT Measures of Emphysema and Small Airways Disease and Lung Function and Exercise Capacity in Smokers with Radiographic Bronchiectasis

RATIONALE AND OBJECTIVES

Bronchiectasis (BE) is associated with chronic obstructive pulmonary disease (COPD), but emphysema and small airways disease, main pathologic features of COPD, have been sparsely studied in BE. We aimed to objectively assess those features in smokers with and without radiographic BE and examine its relationships to airflow obstruction and exercise capacity.

MATERIAL AND METHODS

We measured emphysema and small airways disease on paired inspiratory-expiratory computed tomography (CT) scans with the parametric response map (PRM^EMPH and PRM^SAD) method in 1184 smokers with and without radiographic BE. PRM^SAD and PRM^EMPH are expressed as the percentage of lung area. Clinical, spirometry, and exercise capacity data were measured with standardized methods. The differences in PRM^SAD and PRM^EMPH between subjects with and without radiographic BE were assessed using multivariable linear regression analysis, and their associations with FEV₁ and six-minute walk test (6MWT) were assessed with generalized linear models.

RESULTS

Out of 1184 subjects, 383 (32%) had radiographic BE. PRM^EMPH but not PRM^SAD was higher in subjects with radiographic BE than those without radiographic BE in adjusted models. Subjects with radiographic BE and PRM^EMPH (defined as ≥5% on paired CTs) had lower FEV₁ (least square mean, 1479 mL vs. 2350 mL p < 0.0001) and 6MWT (372 m vs. 426 m p = 0.0007) than those with radiographic BE alone in adjusted models.

CONCLUSION

Smokers with radiographic BE have an increased burden of emphysema on paired CTs, and those with radiographic BE and emphysema have lower airflow and exercise capacity.

A multidisciplinary approach to the management of nontuberculous mycobacterial lung disease: a clinical perspective

INTRODUCTION

Management of nontuberculous mycobacterial lung disease (NTM-LD) can be encumbered by difficult diagnostic criteria and complex treatment decisions. As prevalence of this debilitating, often refractory, progressive lung disease increases globally, management must evolve beyond antimicrobials to encompass holistic and customized treatments coordinated by practitioners across various specialties.

AREAS COVERED

This review aims to complement the recently updated NTM-LD treatment guidelines and expand current approaches to diagnosis, treatment, and disease management in a multidisciplinary dimension. The foundation of effective long-term management of NTM-LD is awareness of diagnostic criteria, individual patient risk factors, and the importance of managing underlying pulmonary and nonpulmonary comorbidities. The value of adopting all available pharmacological and nonpharmacological treatment modalities with a patient-centered approach to address the needs of long-term patient care cannot be minimized.

EXPERT OPINION

This section, while acknowledging the limited advances in understanding of NTM-LD and the availability of newer diagnostic and therapeutic tools over the last decade, underscores the need for a programmatic approach to this chronic, debilitating pulmonary infection. This will not only lead to more comprehensive patient care with better outcomes, but will also inspire and activate robust networks of research and public health initiatives in this field.

Neutrophil extracellular traps, disease severity, and antibiotic response in bronchiectasis: an international, observational, multicohort study

BACKGROUND

Bronchiectasis is predominantly a neutrophilic inflammatory disease. There are no established therapies that directly target neutrophilic inflammation because little is understood of the underlying mechanisms leading to severe disease. Neutrophil extracellular trap (NET) formation is a method of host defence that has been implicated in multiple inflammatory diseases. We aimed to investigate the role of NETs in disease severity and treatment response in bronchiectasis.

METHODS

In this observational study, we did a series of UK and international studies to investigate the role of NETs in disease severity and treatment response in bronchiectasis. First, we used liquid chromatography-tandem mass spectrometry to identify proteomic biomarkers associated with disease severity, defined using the bronchiectasis severity index, in patients with bronchiectasis (n=40) in Dundee, UK. Second, we validated these biomarkers in two cohorts of patients with bronchiectasis, the first comprising 175 patients from the TAYBRIDGE study in the UK and the second comprising 275 patients from the BRIDGE cohort study from centres in Italy, Spain, and UK, using an immunoassay to measure NETs. Third, we investigated whether pathogenic bacteria had a role in NET concentrations in patients with severe bronchiectasis. In a separate study, we enrolled patients with acute exacerbations of bronchiectasis (n=20) in Dundee, treated with intravenous antibiotics for 14 days and proteomics were used to identify proteins associated with treatment response. Findings from this cohort were validated in an independent cohort of patients who were admitted to the same hospital (n=20). Fourth, to assess the potential use of macrolides to reduce NETs in patients with bronchiectasis, we examined two studies of long-term macrolide treatment, one in patients with bronchiectasis (n=52 from the UK) in which patients were given 250 mg of azithromycin three times a week for a year, and a post-hoc analysis of the Australian AMAZES trial in patients with asthma (n=47) who were given 500 mg of azithromycin 3 times per week for a year.

FINDINGS

Sputum proteomics identified that NET-associated proteins were the most abundant and were the proteins most strongly associated with disease severity. This finding was validated in two observational cohorts, in which sputum NETs were associated with bronchiectasis severity index, quality of life, future risk of hospital admission, and mortality. In a subgroup of 20 patients with acute exacerbations, clinical response to intravenous antibiotic treatment was associated with successfully reducing NETs in sputum. Patients with Pseudomonas aeruginosa infection had a lessened proteomic and clinical response to intravenous antibiotic treatment compared with those without Pseudomonas infections, but responded to macrolide therapy. Treatment with low dose azithromycin was associated with a significant reduction in NETs in sputum over 12 months in both bronchiectasis and asthma.

INTERPRETATION

We identified NETs as a key marker of disease severity and treatment response in bronchiectasis. These data support the concept of targeting neutrophilic inflammation with existing and novel therapies.

FUNDING

Scottish Government, British Lung Foundation, and European Multicentre Bronchiectasis Audit and Research Collaboration (EMBARC).

Thrombocytosis during Stable State Predicts Mortality in Bronchiectasis

Rationale: Although platelets are considered key inflammatory mediators in respiratory diseases, their role in bronchiectasis has not been fully explored. Objectives: We hypothesized that thrombocytosis in stable state may be associated with bronchiectasis severity and worse clinical outcomes. Methods: Patients with bronchiectasis have been enrolled from 10 centers in Europe and Israel, with platelet count recorded during stable state. The primary outcome was 5-year all-cause mortality. Secondary outcomes included exacerbations, hospitalizations, and mortality at 1, 2, and 3-year follow-up. Analyses were conducted using logistic regression after adjustment for confounding variables. Results: Among the 1,771 patients (median age, 67 yr; 63.4% female) included, 136 (7.7%) had thrombocytosis. Patients with thrombocytosis had a significantly higher disease severity, worse quality of life, higher number of exacerbations and hospitalizations, and higher mortality rate at both 3-year (23 [22.8%] vs. 83 [8.5%], respectively; P < 0.01) and 5-year (26 [35.1%] vs. 116 [15.9%], respectively; P < 0.01) in comparison with those with normal platelet count. Thrombocytosis was significantly associated with hospitalizations because of severe exacerbations (odds ratio [OR], 1.83; 95% confidence interval [CI], 1.20-2.79; P = 0.01) after 1-year follow-up, as well as increased 3-year (OR, 3.06; 95% CI, 1.74-5.39; P < 0.01) and 5-year (OR, 2.46; 95% CI, 1.39-4.37; P < 0.01) mortality. Conclusions: Platelets represent a cheap and easy-to-evaluate biomarker, and the presence of thrombocytosis during stable state is associated with disease severity, hospitalizations because of exacerbations, poor quality of life, and mortality in adults with bronchiectasis.

Comparative Analysis of Clinical Parameters and Sputum Biomarkers in Establishing the Relevance of Filamentous Fungi in Cystic Fibrosis

Background

The relationship between fungal culture (FC) positivity and airway inflammation in CF is largely unknown. Identifying the clinical significance of filamentous fungi in CF using both clinical parameters and biomarkers may change our antimicrobial therapeutic strategies.

Objectives

To investigate the clinical characteristics and airway biomarker profile in relation to the detection of filamentous fungi in respiratory samples obtained from CF patients.

Methods

A prospective cohort study over 24 months, including children and adults with CF. Participants provided sputum and/or bronchoalveolar lavage samples, which underwent processing for bacterial and fungal culture, leukocyte differential cell count and biomarker analysis for neutrophil elastase (NE), interleukin-8 (IL-8), galactomannan and tumor necrosis factor receptor type 2 (TNF-R2). We performed FC using neat sputum plugs, an approach shown to be more sensitive compared to routine laboratory testing.

Results

Sixty-one patients provided 76 respiratory samples (72 sputum and 4 BAL). Median age was 17 years (range 6 months-59 years). FC positivity was noted in 49% of the cohort. FC positivity was greater during pulmonary exacerbation compared to the stable state (67 versus 50%). Participants aged 5-30 years had a lower FEV1 within the FC positive group. A significant association between FC positivity and non-tuberculosis mycobacterial (NTM) culture was observed on non-parametric testing (p = 0.022) and regression analysis (p = 0.007). Exposure to indoor mold was a predictor for FC positivity (p = 0.047). There was a trend towards increased lung clearance index (LCI), bronchiectasis and intravenous antibiotic use in the FC positive group. There was no significant difference in biomarkers between FC positive and negative patients.

Conclusion

Aspergillus. fumigatus is the commonest filamentous fungi cultured from CF airways. We found no difference in the airway biomarker profile between FC positive and negative patients. The role of galactomannan and TNFR2 as fungal specific biomarkers in CF remains uncertain. FC positivity is associated with a lower FEV₁ in younger patients, a lower LCI, NTM positivity, bronchiectasis, and intravenous antibiotic exposure. Larger trials are needed to determine the role of galactomannan and TNF-R2 as potential fungal biomarkers in CF.

Prospective Observational Study Revealing Early Pulmonary Function Changes Associated With Brigatinib Initiation

INTRODUCTION

Symptomatic early onset pulmonary events (EOPEs) were observed in 3% to 6% of patients within 1 week of starting brigatinib at 90 mg daily for 7 days followed by 180 mg daily. We conducted a prospective observational cohort study to measure pulmonary function changes on initiating brigatinib.

METHODS

Patients initiating brigatinib were eligible. Pulmonary function test (PFT) with diffusing capacity for carbon monoxide (DLCO), Borg dyspnea scale, six-minute walk test, and blood draw for cytometry by time-of-flight were performed at baseline, day 2, and day 8 plus or minus day 15 of brigatinib. The primary end point was the incidence of PFT-defined EOPEs, prespecified as greater than or equal to 20% DLCO reduction from baseline. An interim analysis was performed owing to a higher than expected incidence of DLCO reduction.

RESULTS

A total of 90% (nine of 10) experienced DLCO reduction with the nadir occurring on day 2 or day 8. Median DLCO nadir was -13.33% from baseline (range: -34.44 to -5.00). Three participants met the PFT-defined EOPE criteria. All patients, including these three, were asymptomatic, none required brigatinib interruption or dose reduction, and all patients escalated to 180 mg without further issues. Despite continued dosing, by day 15, all assessed patients experienced DLCO recovery. Dyspnea and six-minute walk test results did not correlate with DLCO changes. Patients with a PFT-defined EOPE had significantly higher levels of activated neutrophils at baseline and day 8.

CONCLUSIONS

DLCO reduction occurred in 90% during the first 8 days of brigatinib dosing without any related symptoms. DLCO improved in all six patients assessed at day 15 despite continued dosing and dose escalation. Pretreatment levels of neutrophil activation should be explored as a biomarker for developing EOPEs.

Phase 2 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis

BACKGROUND

Patients with bronchiectasis have frequent exacerbations that are thought to be related to neutrophilic inflammation. The activity and quantity of neutrophil serine proteases, including neutrophil elastase, are increased in the sputum of patients with bronchiectasis at baseline and increase further during exacerbations. Brensocatib (INS1007) is an oral reversible inhibitor of dipeptidyl peptidase 1 (DPP-1), an enzyme responsible for the activation of neutrophil serine proteases.

METHODS

In a phase 2, randomized, double-blind, placebo-controlled trial, we randomly assigned, in a 1:1:1 ratio, patients with bronchiectasis who had had at least two exacerbations in the previous year to receive placebo, 10 mg of brensocatib, or 25 mg of brensocatib once daily for 24 weeks. The time to the first exacerbation (primary end point), the rate of exacerbations (secondary end point), sputum neutrophil elastase activity, and safety were assessed.

RESULTS

Of 256 patients, 87 were assigned to receive placebo, 82 to receive 10 mg of brensocatib, and 87 to receive 25 mg of brensocatib. The 25th percentile of the time to the first exacerbation was 67 days in the placebo group, 134 days in the 10-mg brensocatib group, and 96 days in the 25-mg brensocatib group. Brensocatib treatment prolonged the time to the first exacerbation as compared with placebo (P = 0.03 for 10-mg brensocatib vs. placebo; P = 0.04 for 25-mg brensocatib vs. placebo). The adjusted hazard ratio for exacerbation in the comparison of brensocatib with placebo was 0.58 (95% confidence interval [CI], 0.35 to 0.95) in the 10-mg group (P = 0.03) and 0.62 (95% CI, 0.38 to 0.99) in the 25-mg group (P = 0.046). The incidence-rate ratio was 0.64 (95% CI, 0.42 to 0.98) in the 10-mg group, as compared with placebo (P = 0.04), and 0.75 (95% CI, 0.50 to 1.13) in the 25-mg group, as compared with placebo (P = 0.17). With both brensocatib doses, sputum neutrophil elastase activity was reduced from baseline over the 24-week treatment period. The incidence of dental and skin adverse events of special interest was higher with the 10-mg and 25-mg brensocatib doses, respectively, than with placebo.

CONCLUSIONS

In this 24-week trial, reduction of neutrophil serine protease activity with brensocatib in patients with bronchiectasis was associated with improvements in bronchiectasis clinical outcomes. (Funded by Insmed; WILLOW ClinicalTrials.gov number, NCT03218917.).

A Cluster Analysis of Bronchiectasis Patients Based on the Airway Immune Profile

BACKGROUND

Clinical heterogeneity in bronchiectasis remains a challenge for improving the appropriate targeting of therapies and patient management. Antimicrobial peptides (AMPs) have been linked to disease severity and phenotype.

RESEARCH QUESTION

Can we identify clusters of patients based on the levels of AMPs, airway inflammation, tissue remodeling, and tissue damage to establish their relationship with disease severity and clinical outcomes?

STUDY DESIGN AND METHODS

A prospective cohort of 128 stable patients with bronchiectasis were recruited across three centers in three different countries (Spain, Scotland, and Italy). A two-step cluster strategy was used to stratify patients according to levels of lactoferrin, lysozyme, LL-37, and secretory leukocyte protease inhibitor in sputum. Measurements of inflammation (IL-8, tumor growth factor β, and IL-6), tissue remodeling and damage (glycosaminoglycan, matrix metallopeptidase 9, neutrophil elastase, and total and bacterial DNA), and neutrophil chemotaxis were assessed.

RESULTS

Three clusters of patients were defined according to distinct airway profiles of AMPs. They represented groups of patients with gradually distinct airway infection and disease severity. Each cluster was associated with an airway profile of inflammation, tissue remodeling, and tissue damage. The relationships between soluble mediators also were distinct between clusters. This analysis allowed the identification of the cluster with the most deregulated local innate immune response. During follow-up, each cluster showed different risk of three or more exacerbations occurring (P = .03) and different times to first exacerbations (P = .03).

INTERPRETATION

Bronchiectasis patients can be stratified in different clusters according to profiles of airway AMPs, inflammation, tissue remodeling, and tissue damage. The combination of these immunologic variables shows a relationship with disease severity and future risk of exacerbations.

The Distribution of Alpha-1 Antitrypsin Genotypes Between Patients with COPD/Emphysema, Asthma and Bronchiectasis

Purpose

Alpha-1-antitrypsin deficiency (AATD) is a rare hereditary condition characterized by low circulating levels of alpha-1antitrypsin (AAT). While the association between AATD and COPD/emphysema is undisputed, the association between AATD and asthma or bronchiectasis is still a matter of debate.

Aims and Objectives

Our study aimed to investigate the distribution of AAT genotypes between patients with COPD/emphysema, asthma and bronchiectasis. To back up the diagnostic labels, we described symptoms associated with the diagnosis.

Methods

Between September 2003 and March 2020, 29,465 testing kits (AlphaKit®) were analyzed in the AAT laboratory, University of Marburg, Germany. The diagnosis of AATD has been made based on the measurements of AAT serum levels, followed by genotyping, phenotyping or whole gene sequencing depending on the availability and/or the need for more detailed interpretation of the results. The respiratory symptoms were recorded as well.

Results

Regarding the distribution of the wild type allele M and the most frequent mutations S (E264V) and Z (E342K), no significant differences could be found between COPD/emphysema [Pi*MM (58.24%); Pi*SZ (2.49%); Pi*ZZ (9.12%)] and bronchiectasis [Pi*MM (59.30%) Pi*SZ (2.81%); Pi*ZZ (7.02%)]. When COPD/emphysema and bronchiectasis were recorded in the same patient, the rate of Pi* ZZ (14.78%) mutations was even higher. Asthma patients exhibited significantly less deficient genotypes [Pi*MM (54.81%); Pi*SZ (2%); Pi*ZZ (2.77%)] than two other groups. Associated respiratory symptoms confirmed the diagnosis.

Conclusion

COPD/emphysema and bronchiectasis, but not asthma patients, exhibit higher frequency of AATD genotypes. Our data suggest that AATD testing should be offered to patients with COPD/emphysema and bronchiectasis.

Sputum neutrophil elastase associates with microbiota and Pseudomonas aeruginosa in bronchiectasis

INTRODUCTION

Neutrophilic inflammation is a major driver of bronchiectasis pathophysiology, and neutrophil elastase activity is the most promising biomarker evaluated in sputum to date. How active neutrophil elastase correlates with the lung microbiome in bronchiectasis is still unexplored. We aimed to understand whether active neutrophil elastase is associated with low microbial diversity and distinct microbiome characteristics.

METHODS

An observational, cross-sectional study was conducted at the bronchiectasis programme of the Policlinico Hospital in Milan, Italy, where adults with bronchiectasis were enrolled between March 2017 and March 2019. Active neutrophil elastase was measured on sputum collected during stable state, microbiota analysed through 16S rRNA gene sequencing, molecular assessment of respiratory pathogens carried out through real-time PCR and clinical data collected.

RESULTS

Among 185 patients enrolled, decreasing α-diversity, evaluated through the Shannon entropy (ρ -0.37, p<0.00001) and Pielou's evenness (ρ -0.36, p<0.00001) and richness (ρ -0.33, p<0.00001), was significantly correlated with increasing elastase. A significant difference in median levels of Shannon entropy as detected between patients with neutrophil elastase ≥20 µg·mL^-1 (median 3.82, interquartile range 2.20-4.96) versus neutrophil elastase <20 µg·mL^-1 (4.88, 3.68-5.80; p<0.0001). A distinct microbiome was found in these two groups, mainly characterised by enrichment with Pseudomonas in the high-elastase group and with Streptococcus in the low-elastase group. Further confirmation of the association of Pseudomonas aeruginosa with elevated active neutrophil elastase was found based on standard culture and targeted real-time PCR.

CONCLUSIONS

High levels of active neutrophil elastase are associated to low microbiome diversity and specifically to P. aeruginosa infection.

The Open Challenge of in vitro Modeling Complex and Multi-Microbial Communities in Three-Dimensional Niches

The comprehension of the underlying mechanisms of the interactions within microbial communities represents a major challenge to be faced to control their outcome. Joint efforts of in vitro, in vivo and ecological models are crucial to controlling human health, including chronic infections. In a broader perspective, considering that polymicrobial communities are ubiquitous in nature, the understanding of these mechanisms is the groundwork to control and modulate bacterial response to any environmental condition. The reduction of the complex nature of communities of microorganisms to a single bacterial strain could not suffice to recapitulate the in vivo situation observed in mammals. Furthermore, some bacteria can adapt to various physiological or arduous environments embedding themselves in three-dimensional matrices, secluding from the external environment. Considering the increasing awareness that dynamic complex and dynamic population of microorganisms (microbiota), inhabiting different apparatuses, regulate different health states and protect against pathogen infections in a fragile and dynamic equilibrium, we underline the need to produce models to mimic the three-dimensional niches in which bacteria, and microorganisms in general, self-organize within a microbial consortium, strive and compete. This review mainly focuses, as a case study, to lung pathology-related dysbiosis and life-threatening diseases such as cystic fibrosis and bronchiectasis, where the co-presence of different bacteria and the altered 3D-environment, can be considered as worst-cases for chronic polymicrobial infections. We illustrate the state-of-art strategies used to study biofilms and bacterial niches in chronic infections, and multispecies ecological competition. Although far from the rendering of the 3D-environments and the polymicrobial nature of the infections, they represent the starting point to face their complexity. The increase of knowledge respect to the above aspects could positively affect the actual healthcare scenario. Indeed, infections are becoming a serious threat, due to the increasing bacterial resistance and the slow release of novel antibiotics on the market.

Relationship between Symptoms, Exacerbations, and Treatment Response in Bronchiectasis

Rationale: Bronchiectasis guidelines regard treatment to prevent exacerbation and treatment of daily symptoms as separate objectives.Objectives: We hypothesized that patients with greater symptoms would be at higher risk of exacerbations and therefore that a treatment aimed at reducing daily symptoms would also reduce exacerbations in highly symptomatic patients.Methods: Our study comprised an observational cohort of 333 patients from the East of Scotland (2012-2016). Either symptoms were modeled as a continuous variable or patients were classified as having high, moderate, or low symptom burden (>70, 40-70, and <40 using the St. George's Respiratory Questionnaire symptom score). The hypothesis that exacerbation reductions would only be evident in highly symptomatic patients was tested in a post hoc analysis of a randomized trial of inhaled dry powder mannitol (N = 461 patients).Measurements and Main Results: In the observational cohort, daily symptoms were a significant predictor of future exacerbations (rate ratio [RR], 1.10; 95% confidence interval [CI], 1.03-1.17; P = 0.005). Patients with higher symptom scores had higher exacerbation rates (RR, 1.74; 95% CI, 1.12-2.72; P = 0.01) over 12-month follow-up than those with lower symptoms. Inhaled mannitol treatment improved the time to first exacerbation (hazard ratio, 0.56; 95% CI, 0.40-0.77; P < 0.001), and the proportion of patients remaining exacerbation free for 12 months of treatment was higher in the mannitol group (32.7% vs. 14.6%; RR, 2.84; 95% CI, 1.40-5.76; P = 0.003), but only in highly symptomatic patients. In contrast, no benefit was evident in patients with lower symptom burden.Conclusions: Highly symptomatic patients have increased risk of exacerbations, and exacerbation benefit with inhaled mannitol was only evident in patients with high symptom burden.

Novel Anti-Inflammatory Approaches for Cystic Fibrosis Lung Disease: Identification of Molecular Targets and Design of Innovative Therapies

Cystic fibrosis (CF) is the most common genetic disorder among Caucasians, estimated to affect more than 70,000 people in the world. Severe and persistent bronchial inflammation and chronic bacterial infection, along with airway mucus obstruction, are hallmarks of CF lung disease and participate in its progression. Anti-inflammatory therapies are, therefore, of particular interest for CF lung disease. Furthermore, a better understanding of the molecular mechanisms involved in airway infection and inflammation in CF has led to the development of new therapeutic approaches that are currently under evaluation by clinical trials. These new strategies dedicated to CF inflammation are designed to treat different dysregulated aspects such as oxidative stress, cytokine secretion, and the targeting of dysregulated pathways. In this review, we summarize the current understanding of the cellular and molecular mechanisms that contribute to abnormal lung inflammation in CF, as well as the new anti-inflammatory strategies proposed to CF patients by exploring novel molecular targets and novel drug approaches.

Inhaled aztreonam improves symptoms of cough and sputum production in patients with bronchiectasis: a post hoc analysis of the AIR-BX studies

INTRODUCTION

Inhaled antibiotics may improve symptom scores, but it is not known which specific symptoms improve with therapy. Item-level analysis of questionnaire data may allow us to identify which specific symptoms respond best to treatment.

METHODS

Post hoc analysis of the AIR-BX1 studies and two trials of inhaled aztreonam versus placebo in bronchiectasis. Individual items from the quality of life bronchiectasis (QOL-B) respiratory symptom scale, were extracted as representing severity of nine distinct symptoms. Generalised linear models were used to evaluate changes in symptoms with treatment versus placebo from baseline to end of first on-treatment cycle and mixed models were used to evaluate changes across the full 16-week trial.

RESULTS

Aztreonam improved cough (difference 0.22, 95% CI 0.08-0.37; p=0.002), sputum production (0.30, 95% CI 0.15-0.44; p<0.0001) and sputum colour (0.29, 95% CI 0.15-0.43; p<0.0001) versus placebo equating to a 20% improvement in cough and 25% improvement in sputum production and colour. Similar results were observed for cough, sputum production and sputum purulence across the trial duration (all p<0.05). Patients with higher sputum production and sputum colour scores had a greater response on the overall QOL-B (difference 4.82, 95% CI 1.12-8.53; p=0.011 for sputum production and 5.02, 95% CI 1.19-8.86; p=0.01 for sputum colour). In contrast, treating patients who had lower levels of bronchitic symptoms resulted in shorter time to next exacerbation (hazard ratio 1.83, 95% CI 1.02-3.28; p=0.042).

CONCLUSION

Baseline bronchitic symptoms predict response to inhaled aztreonam in bronchiectasis. More sensitive tools to measure bronchitic symptoms may be useful to better identify inhaled antibiotic responders and to evaluate patient response to treatment.

C-Reactive Protein Concentration in Steady-State Bronchiectasis: Prognostic Value of Future Severe Exacerbations. Data From the Spanish Registry of Bronchiectasis (RIBRON)

BACKGROUND

Both systemic inflammation and exacerbations have been associated with greater severity of bronchiectasis. Our objective was to analyze the prognostic value of the peripheral concentration of C-reactive protein (CRP) for the number and severity of exacerbations in patients with bronchiectasis.

METHODS

Patients from the Spanish Bronchiectasis Registry (RIBRON) with valid data on their CRP value (in a clinically stable phase) and valid data on exacerbations during the first year of follow-up were included. A logistic regression analysis was used to evaluate the prognostic value of the CRP concentration (divided into tertiles) with the presence of at least one severe exacerbation or at least two mild-moderate exacerbations during the first year of follow-up.

RESULTS

802 patients (mean age: 68.1 [11.1 years], 65% female) were included. Of these, 33.8% and 13%, respectively, presented ≥2 mild-moderate exacerbations or at least one severe exacerbation during the first year of follow-up. The mean value of the CRP was 6.5 (17.6mg/L). Patients with a CRP value between 0.4 and 2.7mg/L (second tertile) and ≥2.7mg/L (third tertile) presented a 2.9 (95%CI: 1.4-5.9) and 4.2 (95%CI: 2.2-8.2) times greater probability, respectively, of experiencing a severe exacerbation than those with <0.4mg/L (control group), regardless of bronchiectasis severity or a history of previous exacerbations. However, the CRP value did not present any prognostic value for the number of mild-moderate exacerbations.

CONCLUSIONS

The CRP value was associated with a greater risk of future severe exacerbations but not with mild or moderate exacerbations in patients with steady-state bronchiectasis.

Inhibition of neutrophil elastase prevents neutrophil extracellular trap formation and rescues mice from endotoxic shock

Neutrophil elastase (NE) is a serine protease stored in the azurophilic granules of neutrophils and released into the extracellular milieu during inflammatory response or formation of neutrophil extracellular traps (NETs). Neutrophils release NETs to entrap pathogens by externalizing their cellular contents in a DNA framework decorated with anti-microbials and proteases, including NE. Importantly, excess NETs in tissues are implicated in numerous pathologies, including sepsis, rheumatoid arthritis, vasculitis, and cancer. However, it remains unknown how to effectively prevent NET formation. Here, we show that NE plays a major role during NET formation and that inhibition of NE is a promising approach for decreasing NET-mediated tissue injury. NE promoted NET formation by human neutrophils. Whereas sivelestat, a small molecule inhibitor of NE, inhibited the formation of NETs in vitro , administration of free sivelestat did not have any efficacy in a murine model of lipopolysaccharide-induced endotoxic shock. To improve the efficacy of sivelestat in vivo, we have developed a nanoparticle system for delivering sivelestat. We demonstrate that nanoparticle-mediated delivery of sivelestat effectively inhibited NET formation, decreased the clinical signs of lung injury, reduced NE and other proinflammatory cytokines in serum, and rescued animals against endotoxic shock. Collectively, our data demonstrates that NE signaling can initiate NET formation and that nanoparticle-mediated inhibition of NE improves drug efficacy for preventing NET formation.

Is bronchiectasis really a disease?

The definition of a disease requires that distinguishing signs and symptoms are present that are common, and that the constellation of signs and symptoms differentiate the condition from other causes. In bronchiectasis, anatomical changes, airways inflammation and airway infection are the distinguishing features that are common to this disease. However, bronchiectasis is a heterogenous disease: signs and symptoms are shared with other airway diseases, there are multiple aetiologies and certain phenotypes of bronchiectasis have distinct clinical and laboratory features that are not common to all people with bronchiectasis. Furthermore, response to therapeutic interventions in clinical trials is not uniform. The concept of bronchiectasis as a treatable trait has been suggested, but this may be too restrictive in view of the heterogeneity of bronchiectasis. It is our opinion that bronchiectasis should be defined as a disease in its own right, but one that shares several pathophysiological features and "treatable traits" with other airway diseases. These traits define the large heterogeneity in the pathogenesis and clinical features and suggest a more targeted approach to therapy.

Bronchiectasis in Primary Antibody Deficiencies: A Multidisciplinary Approach

Bronchiectasis, the presence of bronchial wall thickening with airway dilatation, is a particularly challenging complication of primary antibody deficiencies. While susceptibility to infections may be the primary factor leading to the development of bronchiectasis in these patients, the condition may develop in the absence of known infections. Once bronchiectasis is present, the lungs are subject to a progressive cycle involving both infectious and non-infectious factors. If bronchiectasis is not identified or not managed appropriately, the cycle proceeds unchecked and yields advanced and permanent lung damage. Severe symptoms may limit exercise tolerance, require frequent hospitalizations, profoundly impair quality of life (QOL), and lead to early death. This review article focuses on the appropriate identification and management of bronchiectasis in patients with primary antibody deficiencies. The underlying immune deficiency and the bronchiectasis need to be treated from combined immunology and pulmonary perspectives, reflected in this review by experts from both fields. An aggressive multidisciplinary approach may reduce exacerbations and slow the progression of permanent lung damage.

Airway Bacterial Load and Inhaled Antibiotic Response in Bronchiectasis

Rationale: The principal underlying inhaled antibiotic treatment in bronchiectasis is that airway bacterial load drives inflammation, and therefore antibiotic treatment will reduce symptoms. Objectives: To determine the relationship between bacterial load and clinical outcomes, assess the stability of bacterial load over time, and test the hypothesis that response to inhaled antibiotics would be predicted by baseline bacterial load. Methods: We performed three studies. Studies 1 and 2 were prospective studies including adults with bronchiectasis. Study 3 was a post hoc analysis of a randomized trial of inhaled aztreonam. A priori patients were divided into low (<10⁵ cfu/g), moderate (10⁵-10⁶ cfu/g), and high bacterial load (≥10⁷ cfu/g) using quantitative sputum culture. Measurements and Main Results: Bacterial load was a stable trait associated with worse quality of life and more airway inflammation in studies 1, 2, and 3. In study 3, patients with high bacterial load showed an improvement in the primary endpoint (Quality of Life-Bronchiectasis-Respiratory Symptoms Score at Week 4) in favor of aztreonam (mean difference of 9.7 points; 95% confidence interval, 3.4-16.0; P = 0.003). The proportion of patients who achieved an increase above the minimum clinically important difference was higher in the aztreonam group at Week 4 (63% vs. 37%; P = 0.01) and at Week 12 (62% vs. 38%; P = 0.01) only in high bacterial load patients. Conclusions: Improvement of quality of life with inhaled aztreonam was only evident in patients with high bacterial load. Bacterial load may be a useful biomarker of severity of disease and treatment response.

The Impact of Hypoxia on Neutrophil Degranulation and Consequences for the Host

Neutrophils are key effector cells of innate immunity, rapidly recruited to defend the host against invading pathogens. Neutrophils may kill pathogens intracellularly, following phagocytosis, or extracellularly, by degranulation and the release of neutrophil extracellular traps; all of these microbicidal strategies require the deployment of cytotoxic proteins and proteases, packaged during neutrophil development within cytoplasmic granules. Neutrophils operate in infected and inflamed tissues, which can be profoundly hypoxic. Neutrophilic infiltration of hypoxic tissues characterises a myriad of acute and chronic infectious and inflammatory diseases, and as well as potentially protecting the host from pathogens, neutrophil granule products have been implicated in causing collateral tissue damage in these scenarios. This review discusses the evidence for the enhanced secretion of destructive neutrophil granule contents observed in hypoxic environments and the potential mechanisms for this heightened granule exocytosis, highlighting implications for the host. Understanding the dichotomy of the beneficial and detrimental consequences of neutrophil degranulation in hypoxic environments is crucial to inform potential neutrophil-directed therapeutics in order to limit persistent, excessive, or inappropriate inflammation.

Alpha-1 Antitrypsin-A Target for MicroRNA-Based Therapeutic Development for Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive genetic disorder arising from mutations to the cystic fibrosis transmembrane conductance regulator (CFTR) gene. Disruption to normal ion homeostasis in the airway results in impaired mucociliary clearance, leaving the lung more vulnerable to recurrent and chronic bacterial infections. The CF lung endures an excess of neutrophilic inflammation, and whilst neutrophil serine proteases are a crucial part of the innate host defence to infection, a surplus of neutrophil elastase (NE) is understood to create a net destructive effect. Alpha-1 antitrypsin (A1AT) is a key antiprotease in the control of NE protease activity but is ineffective in the CF lung due to the huge imbalance of NE levels. Therapeutic strategies to boost levels of protective antiproteases such as A1AT in the lung remain an attractive research strategy to limit the damage from excess protease activity. microRNAs are small non-coding RNA molecules that bind specific cognate sequences to inhibit expression of target mRNAs. The inhibition of miRNAs which target the SERPINA1 (A1AT-encoding gene) mRNA represents a novel therapeutic approach for CF inflammation. This could involve the delivery of antagomirs that bind and sequester the target miRNA, or target site blockers that bind miRNA recognition elements within the target mRNA to prevent miRNA interaction. Therefore, miRNA targeted therapies offer an alternative strategy to drive endogenous A1AT production and thus supplement the antiprotease shield of the CF lung.

Bronchiectasis in severe asthma: a distinct phenotype?

PURPOSE OF REVIEW

The presence of bronchiectasis has been described in about 30% of severe asthma patients. The coexistence of these two respiratory conditions poses new challenges from both clinical and research perspectives. We will review the available literature on this topic to discuss the existance of a specific clinical phenotype of asthma.

RECENT FINDINGS

Despite the paucity of literature, the presence of bronchiectasis with severe asthma is associated with older age, chronic bronchial expectoration, rhinosinusitis, more frequent and severe exacerbations, neutrophilic airway inflammation and poor response to usual treatment. Conversely, asthma features are also described in bronchiectasis patients even in the absence of an appropriate diagnosis of asthma. In both cases, there is some evidence supporting the use of bronchodilators, macrolides and respiratory physiotherapy, while the use of inhaled corticosteroids and antibiotics is controversial.

SUMMARY

Based on available evidence on the association between (severe) asthma and bronchiectasis, its pathophysiology, certain clinical aspects and prognosis are largely unclear. Although specific management appears to be required in most cases, in our opinion there is still insufficient evidence to consider it a distinct phenotype of severe asthma. Hopefully, future research will shed more light on this topic and define the best therapeutic approach.