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

Emerging imaging and circulating biomarkers in relation to underlying mechanisms in Bicuspid Aortic Valve aortopathy

Bicuspid Aortic Valve (BAV) is the most prevalent congenital heart defect with an autosomal dominant inheritance. With up to 2% of the general population affected by the condition, mortality remains high likely due to the development of aortopathy which pre-disposes to the development of aortic dissection. Current guidelines focus on surgical management, once a threshold of aorta diameter is surpassed, via routine image surveillance. However, it is recognised that some will develop aortic dissection without meeting these requirements for surgical intervention. Recent literature has begun to address the need for potential biomarkers specific to aortopathy in the BAV population to aid in risk stratification. Four-dimensional cardiovascular magnetic resonance flow imaging has paved the way to the development of imaging measurements such as wall shear stress and reverse flow which aid in the assessment of aberrant blood flow contributing to aortopathy in the BAV group. Differing levels of plasma biomarkers such as matrix metalloproteinases and microRNA have also been associated with aortopathy development furthering insight into the cellular mechanisms involved in aortic vascular matrix remodelling. This article will provide an overview of the recent research into prospective 4-D imaging and circulating biomarkers that have been studied and potential areas of future work.

A profile of brensocatib for non-cystic fibrosis bronchiectasis

INTRODUCTION

Non-cystic-fibrosis bronchiectasis (NCFB) is an airway disorder with a growing worldwide prevalence that affects predominantly older and female individuals and is associated with high symptom burden and significant healthcare expenditure. Brensocatib is a novel orally bioavailable, selective, and reversible dipeptidyl peptidase 1 (DPP1) inhibitor that leads to a sustained inhibition of neutrophil serine protease activity in both whole blood and sputum.

AREAS COVERED

This drug profile summarizes the role of inflammation in the pathophysiology of bronchiectasis. The mechanism of action of brensocatib in reducing neutrophil-related inflammation is described. We then summarize existing efficacy and safety data from Phase 2 and Phase 3 studies of brensocatib in patients with bronchiectasis, in which the rate of exacerbation was the primary endpoint. Finally, we summarize the current marketplace for brensocatib, including the unmet for effective therapies for bronchiectasis, and the status of other potential treatments undergoing clinical trials.

EXPERT OPINION

Brensocatib is a first-in-class DPP1 inhibitor that shows promise as a treatment for patients with bronchiectasis.

Mortality and exacerbations in bronchiectasis patients with carbapenem-resistant Pseudomonas aeruginosa isolation: a long-term retrospective cohort study

BACKGROUND

Few studies have investigated the impact of carbapenem-resistant Pseudomonas aeruginosa (CRPA) on long-term outcomes in bronchiectasis. This study aimed to analyze acute exacerbations and mortality in bronchiectasis patients with CRPA isolation.

METHODS

This retrospective study included bronchiectasis patients with PA-positive cultures from January 1, 2014, to July 31, 2023, at West China Hospital of Sichuan University. PA was isolated from sputum or bronchoalveolar lavage fluid (BALF) and classified into CRPA and non-CRPA groups based on antimicrobial susceptibility testing. Multivariate logistic regression was used to assess risk factors for acute exacerbations, while multivariate Cox regression identified independent risk factors for all-cause and cause-specific mortality.

RESULTS

Among 564 patients with PA-positive isolates, 143 (25.36%) harbored CRPA strains. CRPA isolation was associated with an increased risk of acute exacerbations (adjusted odds ratio [aOR] 2.072, p = 0.001), while antibiotic treatment reduced the risk of exacerbations (aOR 0.439, p = 0.011). CRPA isolation was an independent risk factor for all-cause (adjusted hazard ratio [aHR] 1.488, p = 0.031) and cause-specific mortality (aHR 1.882, p = 0.010). The 1-, 3-, 5-, and 7-year cause-specific survival rates in the CRPA group were 88.6%, 79.8%, 73.2%, and 68.0%, respectively, versus 95.4%, 91.0%, 85.6%, and 81.8% in the non-CRPA group (p = 0.001).

CONCLUSION

CRPA isolation was significantly associated with an increasing risk of acute exacerbations, overall and cause-specific mortality. These findings underscored the urgent need to strengthen antibiotic stewardship to reduce the emergence of CRPA and to implement early detection and targeted management strategies to improve outcomes for patients with CRPA.

Effects of the DPP-1 inhibitor HSK31858 in adults with bronchiectasis in China (SAVE-BE): a phase 2, multicentre, double-blind, randomised, placebo-controlled trial

BACKGROUND

Airway neutrophil inflammation with excessive neutrophil serine proteases is implicated in frequent exacerbations of bronchiectasis. HSK31858 is a novel reversible inhibitor of DPP-1. We aimed to assess the efficacy and safety of HSK31858 in decreasing the frequency of bronchiectasis exacerbations among adults with bronchiectasis.

METHODS

SAVE-BE was a phase 2, double-blind, randomised, placebo-controlled trial in 25 tertiary centres in China. Participants were aged 18 years or older with a physician diagnosis of bronchiectasis, according to chest high-resolution CT showing bronchial dilatation and compatible respiratory symptoms, and at least two exacerbations within 12 months before screening. Participants were randomly assigned (1:1:1) via a central interactive web-response system to receive 20 mg HSK31858, 40 mg HSK31858, or placebo, orally, once daily for 24 weeks. Randomisation was stratified by exacerbation frequency in the previous year (less than three vs three or more annually) and study investigators and participants were masked to group assignment for analysis of study outcomes. The primary endpoint was the annualised exacerbation frequency over 24 weeks, assessed in the full analysis set. Safety was monitored throughout the study. This trial is registered with ClinicalTrials.gov, NCT05601778.

FINDINGS

Between Dec 6, 2022, and March 31, 2024, 292 patients were screened, 226 of whom were enrolled and randomly assigned (75 to the 20 mg HSK31858 group, 76 to the 40 mg HSK31858 group, and 75 to the placebo group. 74 patients received 20 mg HSK31858, 75 received 40 mg HSK31858, and 75 received placebo and were included in the full analysis set. In the full analysis set, 136 (61%) participants were female and 88 (39%) were male. The mean annualised frequency of exacerbations was 1·00 per person-year (SD 1·44) in the 20 mg HSK31858 group, 0·75 per person-year (1·37) in the 40 mg HSK31858 group, and 1·88 per person-year (1·97) in the placebo group. The least-squares mean frequency of exacerbations was 1·05 per person-year (95% CI 0·73-1·51) in the 20 mg HSK31858 group, 0·83 per person-year (0·55-1·25) in the 40 mg HSK31858 group, and 2·01 per person-year (1·53-2·63) in the placebo group. The incidence rate ratio compared with placebo was 0·52 (95% CI 0·34-0·80; p=0·0031) for the 20 mg HSK31858 group and 0·41 (0·26-0·66; p=0·0002) for the 40 mg HSK31858 group. The incidence of adverse events was similar across the three groups. Neither HSK31858 dose was associated with an increased incidence of adverse events of special interest (eg, hyperkeratosis, gingivitis, or life-threatening infections).

INTERPRETATION

Both HSK31858 doses improved clinical outcomes in adults with bronchiectasis, significantly reducing the exacerbation frequency compared with placebo. The development of new drugs targeted at amelioration of neutrophilic inflammation (eg, via suppression of DPP-1 activity) might lead to new options for hindering the progression of bronchiectasis.

FUNDING

Haisco.

Type 2 inflammation, a common denominator in chronic airway disease?

PURPOSE OF REVIEW

This review addresses the growing understanding that a specific subset of patients with a respiratory disease, including asthma, chronic obstructive pulmonary disease (COPD), or bronchiectasis may have one thing in common: type 2 inflammation. In the era of personalized medicine, we need to refine clinical markers combined with molecular and cellular endotyping to improve patient outcomes.

RECENT FINDINGS

Recent literature reveals that type 2 markers such as blood eosinophils, fractional exhaled nitric oxide (FeNO), and immunglobulin E (IgE), can provide valuable insights into disease progression, exacerbation risk, and treatment response, but their stability remains to be investigated. Treating asthma and COPD patients with biologics to target IL-4/IL-13, IL-5, and alarmins have shown potential, although efficacy varied. In bronchiectasis, a subset of patients with type 2 inflammation may benefit from corticosteroid therapy, despite broader concerns regarding its use.

SUMMARY

This underscores the importance of improved disease endotyping to better characterize patients who may benefit from targeted therapies. In clinical practice, personalized treatment based on inflammatory profiles has been shown to improve outcomes in heterogeneous lung diseases. Future research needs to focus on validating reliable biomarkers and optimizing clinical trial designs to advance therapeutic strategies in respiratory diseases.

Phenotypes and endotypes in bronchiectasis: a narrative review of progress toward precision medicine

Background and Objective

Bronchiectasis, which was previously regarded as a rare condition, has recently attracted increased attention with advancements in research and therapeutic strategies. However, heterogeneity remains a major challenge in the management of bronchiectasis. This review aims to elucidate the concepts of phenotypes and endotypes, facilitate a deeper understanding of bronchiectasis complexity, and pave the way for personalized treatment approaches.

Methods

The PubMed database was searched for relevant articles published in English between January 1990 and August 2024 using keywords "bronchiectasis", "phenotype", "endotype", "diagnosis", "disease management", "complexity", "eosino*", "neutrop*", and "precision medicine".

Key Content and Findings

We examined established clinical phenotypes, such as frequent exacerbator and chronic airway disease overlap, which significantly influence prognosis and therapeutic management. The significance of etiology-based phenotyping was also discussed while emphasizing how identifying specific underlying causes can guide targeted therapies. We further explored recent advancements in characterising bronchiectasis endotypes, particularly those marked by neutrophilic and eosinophilic inflammation. These endotypes provide valuable insights into underlying pathophysiological mechanisms and guide the selection of clinical management strategies. Recent cluster analysis research has identified distinct inflammatory endotypes in bronchiectasis, thereby improving the understanding of disease progression and identifying potential therapeutic targets. Integrating molecular endotyping with clinical phenotyping provides a more comprehensive perspective of the disease, underscoring the necessity of a dual approach to effectively address its inherent heterogeneity. Furthermore, we emphasize the significance of identifying treatable traits within these frameworks, which can enhance the precision of treatment strategies and improve patient outcomes. By exploring the interplay between clinical phenotypes, endotypes, and patient-specific characteristics, this review highlights the potential for advancing precision medicine for bronchiectasis.

Conclusions

Enhancing our understanding of bronchiectasis through these concepts is essential for developing tailored interventions that target the underlying biological mechanisms, thereby improving disease management and patients' quality of life.

Phase 3 Trial of the DPP-1 Inhibitor Brensocatib in Bronchiectasis

BACKGROUND

In bronchiectasis, neutrophilic inflammation is associated with an increased risk of exacerbations and disease progression. Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1 (DPP-1), targets neutrophil serine proteases, key mediators of neutrophilic inflammation.

METHODS

In a phase 3, double-blind trial, we randomly assigned patients with bronchiectasis (in a 1:1:1 ratio for adults and a 2:2:1 ratio for adolescents) to receive brensocatib (10 mg or 25 mg once per day) or placebo. The primary end point was the annualized rate of adjudicated pulmonary exacerbations over a 52-week period. The secondary end points, listed in hierarchical testing order, were the time to the first exacerbation during the 52-week period; the percentage of patients remaining exacerbation-free at week 52; the change in forced expiratory volume in 1 second (FEV1); the annualized rate of severe exacerbations; and change in quality of life.

RESULTS

A total of 1721 patients (1680 adults and 41 adolescents) underwent randomization and received brensocatib or placebo. The annualized rate of pulmonary exacerbations was 1.02 in the 10-mg brensocatib group, 1.04 in the 25-mg brensocatib group, and 1.29 in the placebo group (rate ratio, brensocatib vs. placebo, 0.79 [95% confidence interval {CI}, 0.68 to 0.92; adjusted P = 0.004] with the 10-mg dose and 0.81 [95% CI, 0.69 to 0.94; adjusted P = 0.005] with the 25-mg dose). The hazard ratio for the time to the first exacerbation was 0.81 (95% CI, 0.70 to 0.95; adjusted P = 0.02) with the 10-mg dose and 0.83 (95% CI, 0.70 to 0.97; adjusted P = 0.04) with the 25-mg dose. In each brensocatib group, 48.5% of patients remained exacerbation-free at week 52, as compared with 40.3% in the placebo group (rate ratio, 1.20 [95% CI, 1.06 to 1.37; adjusted P = 0.02] with the 10-mg dose and 1.18 [95% CI, 1.04 to 1.34; adjusted P = 0.04] with the 25-mg dose). At week 52, FEV1 had declined by 50 ml with the 10-mg dose, 24 ml with the 25-mg dose, and 62 ml with placebo (least-squares mean difference vs. placebo, 11 ml [95% CI, -14 to 37; adjusted P = 0.38] with the 10-mg dose and 38 ml [95% CI, 11 to 65; adjusted P = 0.04] with the 25-mg dose). The incidence of adverse events was similar across groups, except for a higher incidence of hyperkeratosis with brensocatib.

CONCLUSIONS

Among patients with bronchiectasis, once-daily treatment with brensocatib (10 mg or 25 mg) led to a lower annualized rate of pulmonary exacerbations than placebo, and the decline in FEV1 was less with the 25-mg dose of brensocatib than with placebo. (Funded by Insmed; ASPEN ClinicalTrials.gov number, NCT04594369; EudraCT number, 2020-003688-25.).

Neutrophilic inflammation in bronchiectasis

Noncystic fibrosis bronchiectasis, hereafter referred to as bronchiectasis, is a chronic, progressive lung disease that can affect people of all ages. Patients with clinically significant bronchiectasis have chronic cough and sputum production, as well as recurrent respiratory infections, fatigue and impaired health-related quality of life. The pathophysiology of bronchiectasis has been described as a vicious vortex of chronic inflammation, recurring airway infection, impaired mucociliary clearance and progressive lung damage that promotes the development and progression of the disease. This review describes the pivotal role of neutrophil-driven inflammation in the pathogenesis and progression of bronchiectasis. Delayed neutrophil apoptosis and increased necrosis enhance dysregulated inflammation in bronchiectasis and failure to resolve this contributes to chronic, sustained inflammation. The excessive release of neutrophil serine proteases, such as neutrophil elastase, cathepsin G and proteinase 3, promotes a protease-antiprotease imbalance that correlates with increased inflammation in bronchiectasis and contributes to disease progression. While there are currently no licensed therapies to treat bronchiectasis, this review will explore the evolving evidence for neutrophilic inflammation as a novel treatment target with meaningful clinical benefits.

Increased Neutrophil Elastase in Affected Lobes of Bronchiectasis and Correlation of Its Levels between Sputum and Bronchial Lavage Fluid

BACKGROUND

Neutrophil elastase (NE) has been proposed as a potential biomarker for evaluating the severity and prognosis of bronchiectasis. This study aimed to compare bronchial lavage quantification of NE levels and activities with those of sputum.

METHODS

A cross-sectional study was conducted in which 24 Vietnamese adults with bronchiectasis were enrolled from June 2023 to August 2023. All participants underwent bronchoscopy to collect bronchial lavage fluid (BLF) from two bronchial locations: one in the region with the greatest bronchial dilatation and one in the normal bronchi or in patients with all lobes affected, the least abnormal lobe (abnormal BLF [ABLF] and normal BLF [NBLF], respectively). Spontaneously expectorated sputum was also collected.

RESULTS

Out of 24 cases, the prevalence of mild, moderate and severe bronchiectasis was 14/24 (58.4%), 5/24 (20.8%), and 5/24 (20.8%), respectively. NE concentration and activity were significantly higher in sputum and ABLF than in NBLF (p<0.001). Sputum and ABLF were highly correlated (r=0.841, p<0.001) with no significant difference in NE activity between sputum and ABLF. Higher levels of NE activity were seen in more severe bronchiectasis than in mild bronchiectasis in all samples but were only statistically significant for NE activity in sputum (r=0.418, p=0.042).

CONCLUSION

NE activity and concentration are elevated in areas of the lung most affected by bronchiectasis. Sputum is a valid surrogate of pulmonary NE levels, as they correlate strongly with ABLF and confirm in a Vietnamese population the relationship between NE activity and disease severity.

Serum Desmosine Levels Might Be Associated with the Size of Ruptured Cerebral Aneurysms in Patients with Aneurysmal Subarachnoid Hemorrhage-A Preliminary Study

Background: Aneurysmal subarachnoid hemorrhage (aSAH) is a disease associated with high mortality, caused by the rupture of a cerebral aneurysm. Decision-support scoring systems used for managing unruptured aneurysms (UIAs) include only radiological parameters related to the size and configuration of the aneurysm, without incorporating blood-based markers. Our aim is to identify a serum marker that shows a correlation with aneurysm size in patients with ruptured aneurysms. Methods: Arterial blood samples were collected from patients who experienced aSAH within 24 h of the ictus, and serum desmosine levels were determined using ELISA. The morphological parameters of the aneurysms were assessed during 3D DSA. A favorable outcome was defined as a 3-month mRS score of 0-3. Results: This study included 135 aSAH patients and 25 controls. (i) The desmosine level in serum collected within 24 h after aneurysm rupture in patients with aSAH was significantly higher compared to the serum level in the control group (aSAH: 0.737 ng/mL [IQR: 0.401-1.214], vs. control: 0.365 ng/mL [IQR: 0.251-0.531], p < 0.001); (ii) examining the size of ruptured aneurysms, patients with aneurysms larger than 7 mm had significantly higher serum desmosine levels than those with aneurysms smaller than 7 mm; (iii) in the group with aneurysms smaller than 7 mm, serum desmosine levels correlated with the aneurysm neck width and the size ratio. Conclusions: Serum desmosine shows a strong correlation with the size of ruptured aneurysms in aSAH patients.

Proteomic analysis of premature umbilical cord blood and its relationship with bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) frequently occurs in preterm infants, causing significantly impaired lung function and increased mortality rates. Studies on plasma protein levels can facilitate early detection of BPD, enabling prompt intervention and a decrease in mortality.

METHODS

We conducted a prospective observational study involving proteomic sequencing of plasma samples from 19 preterm infants. Our analysis included principal component analysis, volcano plots, heatmap analysis, enrichment analysis, and receiver operating characteristic (ROC) analysis.

RESULTS

Infants with BPD were characterized by increased levels of lipopolysaccharide (LPS)-binding protein (LBP), X-ray repair cross-complementing protein 6 (XRCC6), GLI pathogenesis-related 1 (GLIPR1), Golgi membrane Protein 1(GOLM1), immunoglobulin kappa variable (IGKV1-5), and immunoglobulin kappa variable 1-33 (IGKV1-33) in cord blood. Additionally, gene pathway analysis revealed a significant correlation between the pathways associated with these genes and BPD, particularly pathways involved in the immune system, innate immune system, neutrophil degranulation, prion diseases, regulation of the actin cytoskeleton, and the MAPK signaling. The proteins amine oxidase copper containing 3 (AOC3) and H4 clustered histone 6 (H4C6) were diagnostically significant. Additionally, H4C6 was negatively correlated with intraventricular haemorrhage and patent ductus arteriosus, and positively correlated with antenatal steroid administration. AOC3 was also positively correlated with antenatal steroid use.

CONCLUSIONS

Our findings suggest that the development of BPD is associated with changes in the plasma proteome of preterm infants. Specifically, the levels of AOC3 and H4C6 in the bloodstream could serve as biomarkers for the early detection of BPD in preterm infants. Furthermore, we found that GOLM1, lipopolysaccharide (LPS)-binding protein, XRCC6, and the contribution of neutrophil degranulation may play a crucial role in the development of therapies for BPD.

The role of neutrophil response in lung damage and post-tuberculosis lung disease: a translational narrative review

It is estimated that more than 150 million individuals alive in 2020 had survived tuberculosis (TB). A portion of this large population continues to experience chronic respiratory abnormalities, with or without symptoms, due to previous active pulmonary TB. This condition known as Post-TB Lung Disease (PTLD), involves a complex interaction between pathogen, host and environmental factors. These interactions are believed to drive a hyperinflammatory process in the lungs during active TB, resulting in tissue damage, which may lead to radiological sequelae, impaired pulmonary function, clinical symptoms, such as cough, dyspnea, hemoptysis, and respiratory infections. Such complications impose significant health, financial, and social burdens, which remain poorly understood and inadequately addressed by health care systems. Given the heterogeneity of immune cells and their products infiltrating the airways and the lung parenchyma during acute and chronic inflammation caused by Mycobacterium tuberculosis infection, it is evident that TB immunopathology is multifactorial. Among the various components involved, neutrophils have recently emerged as critical contributors to the deleterious immune response against TB, leading to severe pulmonary damage. In this translational narrative review, we aim to summarize the role of neutrophils and their primary products - proteases (such as elastase), matrix metalloproteinases and neutrophils extracellular traps (NETs) - in pulmonary TB. We highlight new concepts and emerging evidence of neutrophil involvement during the active disease, translating these insights from "bench to bedside" to facilitate dialogue between fundamental researchers and clinical practitioners. Additionally, we present potential targets for future treatment strategies that could mitigate or even prevent PTLD.

Challenges in treating patients with comorbid asthma and bronchiectasis

The management of patients with overlapping asthma and bronchiectasis requires a tailored approach, starting with a comprehensive assessment of the patient's clinical profile, including the severity of asthma and the extent of bronchiectasis. Inhaled corticosteroids (ICS) are often recommended, but their use should be carefully monitored because of the risk of increased infection. If asthma is well controlled and bronchiectasis remains stable, a gradual reduction in the dose of ICS may be considered. Adjunctive therapies such as macrolides, which have anti-inflammatory and antimicrobial effects, or leukotriene receptor antagonists (LTRAs) may be beneficial. However, LTRAs should be used with caution in patients with bronchiectasis. Long-acting muscarinic antagonists (LAMA), especially in combination with ICS and long-acting beta-agonists (LABA), can improve bronchodilation and reduce inflammation. Although triple therapy (ICS/LABA/LAMA) is promising, its efficacy in bronchiectasis has not yet been confirmed by randomised controlled trials (RCTs). Ongoing monitoring is essential to adjust treatment as the patient's condition evolves. Preventive measures, including vaccination and regular sputum cultures, are important to minimize the risk of infection. Further research and RCTs are needed to better understand the role of dual bronchodilators and triple therapy in the management of overlapping asthma-bronchiectasis.

The impact of COPD-bronchiectasis association on clinical outcomes: insights from East Asian cohorts validating the ROSE criteria

Background

The radiology, obstruction, symptoms and exposure (ROSE) criteria provide a standardised approach for identifying the "COPD-bronchiectasis (BE) association." However, the clinical implications and outcomes of the COPD-BE association in East Asian populations remain unclear. Our study applied the ROSE criteria to assess the prevalence, clinical impact and outcomes of the COPD-BE association in an East Asian cohort, and compared that cohort with nonsmoking BE patients with fixed airflow obstruction (FAO) and those without FAO.

Methods

An integrated cohort analysis was conducted within a Taiwanese demographic, combining a prospective cohort of 147 participants with a multicentre retrospective cohort of 574 participants. Stratification was based on the ROSE criteria, distinguishing between nonsmoking BE, smoking BE, nonsmoking BE with FAO and BE in compliance with the ROSE criteria. Clinical, radiological and spirometric variables were assessed in conjunction with outcomes to validate the diagnostic utility of the criteria.

Results

Using the ROSE criteria, we found that 16.5% of participants had a COPD-BE association (22.4% in the prospective cohort and 14.9% in the retrospective cohort), predominantly in older male patients. These patients had escalated dyspnoea scores, higher COPD diagnosis rates and increased use of inhalation therapies, compared with those without FAO. Notably, patients with a COPD-BE association and nonsmoking BE with FAO displayed similar clinical symptoms, pulmonary function and disease severity, but differed slightly in airway microbiology. Furthermore, patients with a COPD-BE association had significantly higher risks of exacerbations and hospitalisations, even after adjusting for confounding factors, which highlights that they have poorer clinical outcomes than other groups.

Conclusion

The ROSE criteria effectively identify the COPD-BE association in East Asian populations, highlighting a significant future exacerbation risk compared with other BE groups. Future research is warranted to better understand BE progression, especially in FAO subgroups.

A gut Eggerthella lenta-derived metabolite impairs neutrophil function to aggravate bacterial lung infection

The composition of the gut microbiota in patients with bronchiectasis has been proven to be distinct from that of healthy individuals, and this disrupted gut microbiota can exacerbate lung infections. However, the responsible microbes and mechanisms in the "gut-lung" axis in bronchiectasis remain unknown. Here, we report that Eggerthella lenta was enriched in the gut, and taurine ursodeoxycholic acid (TUDCA) was enriched in both the guts and sera of patients with bronchiectasis, with both being associated with disease severity. Fecal microbiota transfer from patients with bronchiectasis as well as administration of E. lenta independently exacerbated pulmonary Pseudomonas aeruginosa infections in murine models. E. lenta-associated TUDCA bound adenosine monophosphate-activated protein kinase (AMPK) within neutrophils and interfered with the interaction between liver kinase B1 and AMPK, with a consequential decrease in AMPK phosphorylation. This ultimately reduced ATP production in neutrophils, inhibited their function, and compromised P. aeruginosa elimination from the lung, aggravating tissue injury. Metformin treatment improved disease severity and outcome in the mouse models. In sum, the gut bacterium E. lenta raises the stakes of bacterial lung infection because it causes dysfunction of neutrophils circulated from serum to lung via the metabolite TUDCA. Interventions targeting E. lenta or AMPK phosphorylation may serve as adjunctive strategies to complement existing approaches for managing chronic pulmonary infection in bronchiectasis and other chronic respiratory disease states.

Neutrophil extracellular traps and macrophage activation contibute to thrombosis and post-covid syndrome in SARS-CoV-2 infection

Background

SARS-CoV-2 infection activates macrophages and induces the release of neutrophil extracellular traps (NETs). Excess NETs is linked to inflammatory and thrombotic complications observed in COVID-19.

Aim

To explore the impact of NETs and macrophage activation on SARS-CoV-2-infected patients who developed complications.

Methods

We included 30 patients from the first (March 2020) and 30 from the second wave (July 2021), collecting two plasma samples at diagnosis and seven days later. Data on demographics, comorbidities, and basic analytical data were compiled. NETs markers (myeloperoxidase (MPO), neutrophil elastase (NE), p-selectin (P-SEL) and S100A8/S100A9 heterodimer (MRP)) and macrophage activation markers (Chitotriosidase activity (ChT), CCL18/PARC and YKL-40) were measured.

Results

The first wave had higher incidences of post-COVID syndrome, ICU admissions, and mortality. Patients of each wave showed elevated blood cells, liver enzymes, and coagulation markers at the time of diagnosis, with fibrinogen and D-Dimer differing between waves. NET and macrophage markers, NE, MPO, MRP, DNAse, ChT, and CCL18 were elevated, while P-SEL, cfDNA, and YKL-40 were decreased if compared to controls. A decrease in NE and DNAse is a link to lower levels of these two markers in complications versus without complications.

Conclusions

This study emonstrates alterations in NETs and macrophage activation markers in COVID-19 patients, indicating an imbalance in inflammatory response regulation.

Proteomics profiling of inflammatory responses to elexacaftor/tezacaftor/ivacaftor in cystic fibrosis

Background

CFTR modulator therapies have positive clinical outcomes, yet chronic inflammation and bacterial infections persist in people with CF (pwCF). How elexacaftor-tezacaftor-ivacaftor (ETI) fails to improve innate immune signaling responsible for bacterial clearance and inflammation resolution remains unknown.

Methods

We used an unbiased proteomics approach to measure the effect of ETI on inflammatory proteins. Plasma from 20 pediatric pwCF and 20 non-CF (NCF) was collected during routine examination and 3 months after ETI initiation. Protein screening was performed with an inflammation panel (Target 96, Olink®). Bioinformatics analysis was used to determine changes in protein expression.

Results

There were significantly fewer pulmonary exacerbations after ETI initiation, along with sustained improvement in lung function and reduced bacterial colonization. Unpaired analysis of CF pre-ETI and NCF resulted in 34 significantly different proteins. Of these, CCL20, MMP-10, EN-RAGE, and AXIN1 had a log2 fold change of 1.2 or more. There was a modest shift in overall CF protein profiles post-ETI toward the NCF cluster. Unpaired analysis of protein differential expression between NCF and CF post-ETI identified a total of 24 proteins significantly impacted by ETI therapy (p-value ≤ 0.05), with only CCL20 having a log2 fold change higher than 1.2. Paired analysis (CF pre- and CF post-ETI) of differential protein expression demonstrated significant expression changes of MMP-10, EN-RAGE, and IL-17A. Pathway analysis identified significantly impacted pathways such as the NF-κB pathway.

Conclusion

This study showed that ETI in a pediatric cohort had a modest effect on several inflammatory proteins with potential as biomarkers. Pathways significantly impacted by ETI can be further studied for future therapies to combat persistent inflammation and dysregulated immunity.

The Contribution of Carbapenem-Resistant Pseudomonas Aeruginosa Isolation to Clinical Outcomes in Hospitalized Patients with Exacerbations of Bronchiectasis: A Retrospective Cohort Study

BACKGROUND

The antibiotic resistance of Pseudomonas aeruginosa (PA) is increasingly severe in bronchiectasis patients. However, there is currently a lack of research on the clinical outcomes of carbapenem-resistant PA (CRPA) isolation in hospitalized exacerbations of bronchiectasis (HEB) patients. We investigated the incidence, risk factors, and clinical outcomes of PA and CRPA isolation in HEB patients.

METHODS

This was an observational, retrospective cohort study of PA and CRPA isolated from sputum or bronchoalveolar lavage fluid cultures of HEB patients from January 1, 2018 to December 31, 2022. The primary outcomes were respiratory failure, mechanical ventilation, and length of hospital stay. The incidence, risk factors, and clinical outcomes of PA and CRPA isolation were analyzed using multivariate logistic and Poisson regression.

RESULTS

Among 1,286 patients, the prevalence of PA, CRPA, and multi-drug resistant PA isolation was 20.61% (n = 265), 3.81% (n = 49), and 5.83% (n = 75), respectively. CRPA isolation was associated with an increased risk for respiratory failure (adjusted odds ratio (aOR) 2.56; 95% confidence interval (CI) [1.29, 5.11]; p = 0.007), mechanical ventilation (aOR 3.65; 95% CI [1.50, 8.92]; p = 0.004), and length of hospital stay (Coefficient (Coef) 0.27; 95% CI [0.18,0.35]; p < 0.001) compared to non-CRPA. Antibiotic treatment decreased the risk of respiratory failure (aOR 0.37; 95% CI [0.17, 0.80]; p = 0.011), mechanical ventilation (aOR 0.36; 95% CI [0.13, 0.99]; p = 0.047), and length of hospital stay (Coef - 0.23; 95% CI [- 0.33, - 0.14]; p < 0.001).

CONCLUSIONS

CRPA isolation was identified in more severe bronchiectasis patients and significantly increased the risk of respiratory failure, mechanical ventilation and length of hospital stay, while antibiotic treatment reduced this risk.

Targeting neutrophil serine proteases in bronchiectasis

Persistent neutrophilic inflammation is a central feature in both the pathogenesis and progression of bronchiectasis. Neutrophils release neutrophil serine proteases (NSPs), such as neutrophil elastase (NE), cathepsin G and proteinase 3. When chronically high levels of free NSP activity exceed those of protective antiproteases, structural lung destruction, mucosal-related defects, further susceptibility to infection and worsening of clinical outcomes can occur. Despite the defined role of prolonged, high levels of NSPs in bronchiectasis, no drug that controls neutrophilic inflammation is licensed for the treatment of bronchiectasis. Previous methods of suppressing neutrophilic inflammation (such as direct inhibition of NE) have not been successful; however, an emerging therapy designed to address neutrophil-mediated pathology, inhibition of the cysteine protease cathepsin C (CatC, also known as dipeptidyl peptidase 1), is a promising approach to ameliorate neutrophilic inflammation, since this may reduce the activity of all NSPs implicated in bronchiectasis pathogenesis, and not just NE. Current data suggest that CatC inhibition may effectively restore the protease-antiprotease balance in bronchiectasis and improve disease outcomes as a result. Clinical trials for CatC inhibitors in bronchiectasis have reported positive phase III results. In this narrative review, we discuss the role of high NSP activity in bronchiectasis, and how this feature drives the associated morbidity and mortality seen in bronchiectasis. This review discusses therapeutic approaches aimed at treating neutrophilic inflammation in the bronchiectasis lung, summarising clinical trial outcomes and highlighting the need for more treatment strategies that effectively address chronic neutrophilic inflammation in bronchiectasis.

Disease Severity and Activity in Bronchiectasis: A Paradigm Shift in Bronchiectasis Management

Bronchiectasis has an increasing prevalence and substantial clinical and economic burden. Therefore, physicians should identify patients with bronchiectasis at high risk of disease progression to ensure optimal management in advance. The heterogeneity of bronchiectasis means it is unlikely that any single parameter could identify highrisk patients; therefore, disease severity is usually assessed using validated composite tools, such as the Bronchiectasis Severity Index, FACED, and Bronchiectasis Aetiology Comorbidity Index, to predict long-term outcomes in bronchiectasis. Disease severity, however, implies an advanced process with lung destruction. Earlier intervention may prevent disease progression and improve outcomes. To identify patients at risk, rather than patients with established advanced disease, we need to shift our focus from disease severity to disease activity. Disease activity denotes the activation level of underlying pathophysiological processes and can be measured using clinical presentations and biomarkers. This review discusses a paradigm shift in bronchiectasis management, focusing on disease activity rather than severity, to prevent disease progression.

Brensocatib in patients with bronchiectasis: subgroup analyses from the WILLOW trial

Introduction

Bronchiectasis is a chronic inflammatory airway disease. Brensocatib, an oral, reversible inhibitor of dipeptidyl peptidase 1 (DPP1), reduces pulmonary inflammation by preventing the activation of neutrophil serine proteases. In the phase II WILLOW trial, brensocatib prolonged time to first exacerbation in patients with bronchiectasis. In this post hoc analysis we compare clinical outcomes in patients from WILLOW according to baseline disease characteristics.

Methods

Adults with bronchiectasis treated with brensocatib (10 or 25 mg) or placebo once daily were analysed by baseline Bronchiectasis Severity Index (BSI) score (≤4 (mild), 5-8 (moderate), or ≥9 (severe)), exacerbation history (2 or ≥3 in the previous year), blood eosinophil count (<300 cells per µL or ≥300 cells per µL), long-term macrolide use (≥6 months; no or yes) and Pseudomonas aeruginosa culture at screening (negative or positive). End-points were time to first exacerbation, annualised exacerbation rate, change in lung function from baseline, and safety. All patients who received brensocatib were pooled and compared with placebo.

Results

Treatment with brensocatib versus placebo was associated with a longer time to first exacerbation (hazard ratio (95% confidence interval), BSI: ≤4, 0.28 (0.08-0.96); 5-8, 0.75 (0.35-1.60); ≥9, 0.61 (0.35-1.04); prior exacerbations: 2, 0.56 (0.34-0.90); ≥3, 0.71 (0.32-1.59); blood eosinophils per µL: <300, 0.66 (0.42-1.06); ≥300, 0.49 (0.20-1.20); long-term macrolide use: no, 0.60 (0.38-0.94); yes, 0.60 (0.25-1.45); P. aeruginosa culture: negative, 0.54 (0.32-0.92); positive, 0.68 (0.37-1.27)). Safety results were similar across subgroups.

Discussion

Patients treated with brensocatib had a numerically longer time to first exacerbation and reduced annualised rate of exacerbation versus placebo across all key baseline disease characteristics.

Accelerating isotope dilution LC-MS-based desmosine quantification for estimating elastin turnover

AIMS

Circulating total desmosine, representing endogenous systemic elastin degradation activity, is an emerging biomarker for mortality risk in several diseases and aging. However, the existing analytical method takes more than 23 hours to complete, limiting its potential applications. The objective of this study was to shorten the turnover time of a stable isotope dilution liquid chromatogram mass spectrometry-based desmosine assay.

MATERIALS & METHODS

Plasma samples were analyzed using acid hydrolysis followed by solid-phase extraction and LC-MS. Two approaches to reduce assay time were tested: microwave-assisted acid hydrolysis and direct injection following solid-phase extraction.

RESULTS

The combination of acid hydrolysis at 180°C for 8 minutes and a low-volume elution design for solid-phase extraction reduced the overall assay time to ~ 30 minutes. The assay was validated with intra-day precision and accuracy ranging from 4% to 14%, and -7% to 9%, respectively, while inter-day precision and accuracy were 0% to 9% and 1% to 3%, respectively. The assay was tested in a cohort of patients with acute aortic dissection and control subjects, where desmosine concentrations were approximately three-fold higher in patients.

CONCLUSIONS

These results demonstrated that rapid desmosine analysis can be achieved with the use of both microwave-assisted hydrolysis and streamlined solid-phase extraction.

The precision medicine strategy to treat COPD pulmonary traits in clinical practice: The role of N-acetylcysteine

Chronic obstructive pulmonary disease (COPD) is a progressive lung condition and a leading cause of physical decline and death. COPD prevalence is expected to increase steadily in the coming years, and as a result, the healthcare and social burden of this condition will intensify. In this scenario, a patient-centric approach, the treatable trait (TT) strategy, based on the identification of traits that are clinically relevant, identifiable, monitorable and treatable, has emerged. The TT strategy, which considers behavioral/risk factors, as well as pulmonary and extrapulmonary traits, has shown to be a promising strategy in COPD management. This work reviews the TT strategy in COPD, giving special attention to the most relevant pulmonary traits, such as frequent productive cough, chronic bronchitis, type 2 inflammation, neutrophilic inflammation, lung hyperinflation, bronchiectasis, exacerbations and non-reversible airflow limitation. N-acetylcysteine (NAC), a widely used mucolytic agent, might be a major player in this strategy. Indeed, through a thorough review of the literature, it has been possible to highlight that, besides being essential in the treatment of frequent productive cough, NAC could bring benefits in case of airflow limitations, airways inflammation, exacerbations and bronchiectasis. A clinical case in which the TT strategy was able to reduce symptoms and improve lung function and quality of life, minimizing unnecessary medication and side effects, is also presented. The identification of TTs and their proper treatment through personalized medicine remarkably ameliorates COPD management. Of note, the mucolytic, antioxidant, and anti-inflammatory activities of NAC might have beneficial effects on several TTs.

Rethinking bronchiectasis as an inflammatory disease

Bronchiectasis is understood to be the result of a complex interaction between infection, impaired mucociliary clearance, inflammation, and lung damage. Current therapeutic approaches to bronchiectasis are heavily focused on management of infection along with enhancing mucus clearance. Long-term antibiotics have had limited success in clinical trials, suggesting a need to re-evaluate the concept of bronchiectasis as an infective disorder. We invoke the example of asthma, for which treatment paradigms shifted away from targeting smooth muscle constriction, towards permanently suppressing airway inflammation, reducing risk and ultimately inducing remission with precision anti-inflammatory treatments. In this Review, we argue that bronchiectasis is primarily a chronic inflammatory disease, requiring early identification of at-risk individuals, and we introduce a novel concept of disease activity with important implications for clinical practice and future research. A new generation of novel anti-inflammatory treatments are under development and repurposing of anti-inflammatory agents from other diseases could revolutionise patient care.

[Management of adult bronchiectasis - Consensus-based Guidelines for the German Respiratory Society (DGP) e. V. (AWMF registration number 020-030)]

Bronchiectasis is an etiologically heterogeneous, chronic, and often progressive respiratory disease characterized by irreversible bronchial dilation. It is frequently associated with significant symptom burden, multiple complications, and reduced quality of life. For several years, there has been a marked global increase in the prevalence of bronchiectasis, which is linked to a substantial economic burden on healthcare systems. This consensus-based guideline is the first German-language guideline addressing the management of bronchiectasis in adults. The guideline emphasizes the importance of thoracic imaging using CT for diagnosis and differentiation of bronchiectasis and highlights the significance of etiology in determining treatment approaches. Both non-drug and drug treatments are comprehensively covered. Non-pharmacological measures include smoking cessation, physiotherapy, physical training, rehabilitation, non-invasive ventilation, thoracic surgery, and lung transplantation. Pharmacological treatments focus on the long-term use of mucolytics, bronchodilators, anti-inflammatory medications, and antibiotics. Additionally, the guideline covers the challenges and strategies for managing upper airway involvement, comorbidities, and exacerbations, as well as socio-medical aspects and disability rights. The importance of patient education and self-management is also emphasized. Finally, the guideline addresses special life stages such as transition, family planning, pregnancy and parenthood, and palliative care. The aim is to ensure comprehensive, consensus-based, and patient-centered care, taking into account individual risks and needs.

Flagellar motility and the mucus environment influence aggregation mediated antibiotic tolerance of Pseudomonas aeruginosa in chronic lung infection

Pseudomonas aeruginosa frequently causes chronic lung infection in individuals with muco-obstructive airway diseases (MADs). Chronic P. aeruginosa infections are difficult to treat, primarily owing to antibiotic treatment failure, which is often observed in the absence of antimicrobial resistance. In MADs, P. aeruginosa forms biofilm-like aggregates within the luminal mucus. While the contribution of mucin hyperconcentration towards antibiotic tolerance has been described, the mechanism for mucin driven antibiotic tolerance and the influence of aggregates have not been fully elucidated. In this study, we investigated the contribution of flagellar motility towards aggregate formation as it relates to the diseased mucus environment. We found that loss of flagellar motility resulted in increased P. aeruginosa aggregation and tolerance to multiple classes of antibiotics. Further, we observed differential roles in antimicrobial tolerance of the motAB and motCD stators, which power the flagellum. Additionally, we found that control of fliC expression was important for aggregate formation and antibiotic tolerance as a strain constitutively expressing fliC was unable to form aggregates and was highly susceptible to treatment. Lastly, we demonstrate that neutrophil elastase, an abundant immune mediator and biomarker of chronic lung infection, promotes aggregation and antibiotic tolerance by impairing flagellar motility. Collectively, these results highlight the key role of flagellar motility in aggregate formation and antibiotic tolerance and deepens our understanding of how the MADs lung environment promotes antibiotic tolerance of P. aeruginosa.

Epidemiology of bronchiectasis at a single center in Japan: a retrospective cohort study

BACKGROUND

The characteristics of bronchiectasis (BE) in Asia, including Japan, remain largely unknown. We aimed to provide insights into the clinical characteristics and treatment outcomes of BE, especially regarding nontuberculous mycobacteria (NTM) infection and its poorly understood impact on prognosis. We also aimed to clarify the effect of long-term macrolide antibiotic use in patients with BE, who had no history of exacerbations.

METHODS

In this single-center, retrospective study, the medical records of patients who satisfied the BE criteria between January 1, 2012, and August 31, 2023, were reviewed. Severe exacerbations and mortality during the observation period were recorded. Baseline characteristics and overall survival of patients with and without NTM infection, and factors influencing the time to the first exacerbation and death were analyzed. Additionally, the effects of long-term macrolide antibiotic use in patients without a history of severe exacerbations were estimated.

RESULTS

In a cohort of 1044 patients with BE, the rate of severe exacerbation was 22.3%, with mortality rates of 3.2% over 3 years. Notably, the high prevalence of NTM infection (n = 410, 39.3%) in this cohort was distinctive. NTM infection was not associated with either the time to first severe exacerbation (p = 0.5676, adjusted hazard ratio = 1.11) or mortality (p = 0.4139, adjusted hazard ratio = 0.78). Compared with the NTM group, the non-NTM group had a higher proportion of elevated inflammatory markers, with significant differences in C-reactive protein levels (p = 0.0301) and blood neutrophil counts (p = 0.0273). Pseudomonas aeruginosa colonization was more frequent in the non-NTM group (p = 0.0003). Among patients with non-NTM infection and without a history of exacerbation in the past 2 years, 38.2% received long-term macrolide antibiotics that did not invariably prolong the time to first severe exacerbation (p = 0.4517, IPW p = 0.3555).

CONCLUSIONS

This study highlights BE epidemiology in Japan, noting that the presence of NTM infection may not necessarily worsen the prognostic outcomes and advising caution in the casual use of macrolides for milder cases without a history of exacerbations.

CLINICAL TRIAL REGISTRATION

UMIN Clinical Trials Registry Number: UMIN000054726 (Registered on 21 June 2024).

Type 2 Biomarkers and Their Clinical Implications in Bronchiectasis: A Prospective Cohort Study

PURPOSE

Bronchiectasis is predominantly marked by neutrophilic inflammation. The relevance of type 2 biomarkers in disease severity and exacerbation risk is poorly understood. This study explores the clinical significance of these biomarkers in bronchiectasis patients.

METHODS

In a cross-sectional cohort study, bronchiectasis patients, excluding those with asthma or allergic bronchopulmonary aspergillosis, underwent clinical and radiological evaluations. Bronchoalveolar lavage samples were analyzed for cytokines and microbiology. Blood eosinophil count (BEC), serum total immunoglobulin E (IgE), and fractional exhaled nitric oxide (FeNO) were measured during stable disease states. Positive type 2 biomarkers were defined by established thresholds for BEC, total IgE, and FeNO.

RESULTS

Among 130 patients, 15.3% demonstrated BEC ≥ 300 cells/μL, 26.1% showed elevated FeNO ≥ 25 ppb, and 36.9% had high serum total IgE ≥ 75 kU/L. Approximately 60% had at least one positive type 2 biomarker. The impact on clinical characteristics and disease severity was variable, highlighting BEC and FeNO as reflective of different facets of disease severity and exacerbation risk. The combination of low BEC with high FeNO appeared to indicate a lower risk of exacerbation. However, Pseudomonas aeruginosa colonization and a high neutrophil-to-lymphocyte ratio (NLR ≥ 3.0) were identified as more significant predictors of exacerbation frequency, independent of type 2 biomarker presence.

CONCLUSIONS

Our study underscores the distinct roles of type 2 biomarkers, highlighting BEC and FeNO, in bronchiectasis for assessing disease severity and predicting exacerbation risk. It advocates for a multi-biomarker strategy, incorporating these with microbiological and clinical assessments, for comprehensive patient management.

The Association Between Systemic Immune-Inflammation Index at Admission and Readmission in Patients with Bronchiectasis

Purpose

Systemic Immune-Inflammation Index (SII), calculated by (neutrophils count × platelet count)/lymphocytes count, is a novel index of the local immune response and systemic inflammation response. The SII has been shown to play an important role in the prognosis of many diseases, including cardiovascular diseases, cancer and COPD. However, its role in the prognosis of bronchiectasis remains unclear and requires further investigation. This study aimed to investigate the association between SII and readmissions in patients with acute exacerbations of bronchiectasis.

Patients and Methods

We conducted a retrospective cohort study of all bronchiectasis patients admitted to the respiratory ward in Beijing Chaoyang Hospital from January 2020 to January 2022. Patients were classified into four groups according to the quartiles of log2(SII) at admission. The primary endpoint was readmission at 1-year follow up. Univariate and multivariate cox regression models were applied to investigate the relationship between SII and readmissions at 1-year follow up in patients with bronchiectasis.

Results

A total of 521 patients were included in our study. The median (IQR) SII at admission were 506.10 (564.84). Patients with higher SII tended to be older, male, past and current smokers, have lower BMI, and more dyspnea symptoms. They also had higher inflammatory markers and received a greater spectrum of antibiotics and more intravenous glucocorticoids. Higher SII at admission were independently associated with readmission in patients with acute exacerbations for bronchiectasis following confounder adjustment (OR =1.007; 95% CI, 1.003-1.011; p <0.001).

Conclusion

Patients with elevated SII levels were typically older males, often smokers, with lower BMI and increased dyspnea. They received more antibiotics and intravenous glucocorticoids. Higher SII at admission are associated with readmission in patients with acute exacerbations of bronchiectasis. SII has potential clinical value as a predictive biomarker for clinical outcomes in bronchiectasis, offering a valuable tool for management strategies.

IL-6 and TIMP-1 Correlated to Airway Pathogen Colonization and Predict Disease Severity in Patients with Non-Cystic Fibrosis Bronchiectasis

Background

Non-cystic fibrosis bronchiectasis is associated with airway pathogen colonization. We planned to investigate the inflammatory markers in patients with different airway pathogens and their correlation with disease severity.

Methods

We enrolled patients aged between 20 and 75 from October 2021 to August 2022. All patients had sputum evaluation for bacterial and fungal cultures before enrollment, and were classified into four groups according to the culture results.

Results

Forty-four patients with non-CF bronchiectasis and six controls were enrolled and categorized as follows: Group 1, no pathogens identified in sputum cultures (n = 14); Group 2, positive fungal culture results (n = 18); Group 3, positive P. aeruginosa culture results (n = 7); and Group 4, positive culture results for both fungi and P. aeruginosa (n = 5). Group 4 had significantly higher serum defensin α1, IL-6 and tissue inhibitors of MMP (TIMP)-1 levels than group 1 patients. The serum levels of IL-6 and TIMP-1 were positively correlated with the FACED score and negatively correlated with distance-saturation product.

Conclusion

Significantly higher levels of serum IL-6 and TIMP-1 were found in the patients who had concomitant fungal and P. aeruginosa colonization, and were closely related to clinical severity and may have important roles in disease monitoring.

The clinical impacts of lung microbiome in bronchiectasis with fixed airflow obstruction: a prospective cohort study

BACKGROUND

Airflow obstruction is a hallmark of disease severity and prognosis in bronchiectasis. The relationship between lung microbiota, airway inflammation, and outcomes in bronchiectasis with fixed airflow obstruction (FAO) remains unclear. This study explores these interactions in bronchiectasis patients, with and without FAO, and compares them to those diagnosed with chronic obstructive pulmonary disease (COPD).

METHODS

This prospective observational study in Taiwan enrolled patients with either bronchiectasis or COPD. To analyze the lung microbiome and assess inflammatory markers, bronchoalveolar lavage (BAL) samples were collected for 16S rRNA gene sequencing. The study cohort comprised 181 patients: 86 with COPD, 46 with bronchiectasis, and 49 with bronchiectasis and FAO, as confirmed by spirometry.

RESULTS

Patients with bronchiectasis, with or without FAO, had similar microbiome profiles characterized by reduced alpha diversity and a predominance of Proteobacteria, distinctly different from COPD patients who exhibited more Firmicutes, greater diversity, and more commensal taxa. Furthermore, compared to COPD and bronchiectasis without FAO, bronchiectasis with FAO showed more severe disease and a higher risk of exacerbations. A significant correlation was found between the presence of Pseudomonas aeruginosa and increased airway neutrophilic inflammation such as Interleukin [IL]-1β, IL-8, and tumor necrosis factor-alpha [TNF]-α, as well as with higher bronchiectasis severity, which might contribute to an increased risk of exacerbations. Moreover, in bronchiectasis patients with FAO, the ROSE (Radiology, Obstruction, Symptoms, and Exposure) criteria were employed to classify individuals as either ROSE (+) or ROSE (-), based on smoking history. This classification highlighted differences in clinical features, inflammatory profiles, and slight microbiome variations between ROSE (-) and ROSE (+) patients, suggesting diverse endotypes within the bronchiectasis with FAO group.

CONCLUSION

Bronchiectasis patients with FAO may exhibit two distinct endotypes, as defined by ROSE criteria, characterized by greater disease severity and a lung microbiome more similar to bronchiectasis without FAO than to COPD. The significant correlation between Pseudomonas aeruginosa colonization and increased airway neutrophilic inflammation, as well as disease severity, underscores the clinical relevance of microbial patterns. This finding reinforces the potential role of these patterns in the progression and exacerbations of bronchiectasis with FAO.

Construction of a panoramic mRNA map of adult noncystic fibrosis bronchiectasis and a preliminary study of the underlying molecular mechanisms

BACKGROUND

The pathogenesis of noncystic fibrosis bronchiectasis in adults is complex, and the relevant molecular mechanisms remain unclear. In this study, we constructed a panoramic map of bronchiectasis mRNA, explored the potential molecular mechanisms, and identified potential therapeutic targets, thus providing a new clinical perspective for the preventive management of bronchiectasis and its acute exacerbation.

METHODS

The mRNA profiles of peripheral blood and bronchiectasis tissues were obtained through transcriptome sequencing and public databases, and bioinformatics methods were used to screen for differentially expressed genes (DEGs). The DEGs were then subjected to biological function and pathway analyses. Some DEGs were validated using a real-time quantitative polymerase chain reaction (RT-qPCR) in peripheral blood. Spearman's correlation analysis was used to analyse the correlation between DEGs and clinical indicators.

RESULTS

Based on transcriptome sequencing and public databases, the mRNA profile of bronchiectasis was determined. DEGs were obtained from the peripheral blood sequencing dataset (985 DEGs), tissue sequencing dataset (2919 DEGs), and GSE97258 dataset (1083 DEGs). Bioinformatics analysis showed that upregulated DEGs had enriched neutrophil-related pathways, and downregulated DEGs had enriched ribosome-related pathways. RT-qPCR testing confirmed the upregulated expression of VCAN, SESTD1, SLC12A1, CD177, IFI44L, SIGLEC1, and RSAD2 in bronchiectasis. These genes were related to many clinical parameters, such as neutrophils, C-reactive protein, and procalcitonin (P < 0.05).

CONCLUSIONS

Transcriptomic methods were used to construct a panoramic map of bronchiectasis mRNA expression. The findings showed that neutrophil activation, chronic inflammation, immune regulation, impaired ribosomal function, oxidative phosphorylation, and energy metabolism disorders are important factors in the development of bronchiectasis. VCAN, SESTD1, SLC12A1, CD177, IFI44L, SIGLEC1, and RSAD2 may play important roles in the pathogenesis of bronchiectasis and are potential therapeutic targets.

Novel cathepsin C inhibitor, BI 1291583, intended for treatment of bronchiectasis: Phase I characterization in healthy volunteers

Novel treatments are needed to reduce inflammation, improve symptoms, address exacerbations, and slow disease progression in bronchiectasis. Cathepsin C (CatC) inhibition promises to achieve this through reduction of neutrophil-derived serine protease (including neutrophil elastase [NE] and proteinase 3 [PR3]) activation. Here, we present the phase I characterization of the novel CatC inhibitor, BI 1291583. Five phase I trials of BI 1291583 in healthy subjects are presented: a single-rising-dose study (NCT03414008) and two multiple-rising-dose studies (NCT03868540 and NCT04866160) assessing the safety, tolerability, pharmacodynamics, and pharmacokinetics of BI 1291583; a food effect study (NCT03837964); and a drug-drug interaction study (NCT03890887) of BI 1291583 and itraconazole. BI 1291583 was safe and well tolerated across the doses tested in these trials. Most adverse events (AEs) were mild or moderate in intensity, with no serious AEs, AEs of special interest or deaths reported in any trial. Drug-related skin exfoliation was not reported more frequently in subjects treated with BI 1291583 compared with placebo. BI 1291583 was readily absorbed, and pharmacokinetics were supra-proportional over the dose ranges assessed. Additionally, BI 1291583 inhibited CatC in a dose-dependent manner, inhibited downstream NE activity, and decreased PR3 levels. No food effect was observed. Co-administration of multiple doses of itraconazole increased BI 1291583 exposure approximately twofold. Due to these promising phase I results, a multinational phase II program of BI 1291583 in adults with bronchiectasis is ongoing (Airleaf™ [NCT05238675], Clairafly™ [NCT05865886], and Clairleaf™ [NCT05846230]).

[Bronchiectasis not due to cystic fibrosis]

Bronchiectasis is a clinical-radiological condition composed of irreversible bronchial dilation due to inflammation and infection of the airways, which causes respiratory symptoms, usually productive cough and infectious exacerbations. Bronchiectasis can have multiple causes, both pulmonary and extrapulmonary, and its clinical presentation is very heterogenous. Its prevalence is unknown, although up to 35-50% of severe COPD and 25% of severe asthma present them, so their underdiagnosis is evident. Chronic bacterial bronchial infection is common, and Pseudomonas aeruginosa is the pathogen that has been found to imply a worse prognosis. Treatment of bronchiectasis has three fundamental characteristics: it must be multidisciplinary (involvement of several specialties), pyramidal (from primary care to the most specialized units) and multidimensional (management of all aspects that make up the disease).

Pharmacologic inhibition of dipeptidyl peptidase 1 (cathepsin C) does not block in vitro granzyme-mediated target cell killing by CD8 T or NK cells

Recently developed small-molecule inhibitors of the lysosomal protease dipeptidyl peptidase 1 (DPP1), also known as cathepsin C (CatC), can suppress suppurative inflammation in vivo by blocking the processing of zymogenic (pro-) forms of neutrophil serine proteases (NSPs), including neutrophil elastase, proteinase 3, and cathepsin G. DPP1 also plays an important role in activating granzyme serine proteases that are expressed by cytotoxic T lymphocytes (CTL) and natural killer (NK) cells. Therefore, it is critical to determine whether DPP1 inhibition can also cause off-target suppression of CTL/NK-cell-mediated killing of virus-infected or malignant cells. Herein, we demonstrate that the processing of human granzymes A and B, transitioning from zymogen to active proteases, is not solely dependent on DPP1. Thus, the killing of target cells by primary human CD8+ T cells, NK cells, and gene-engineered anti-CD19 CAR T cells was not blocked in vitro even after prior exposure to high concentrations of the reversible DPP1 inhibitor brensocatib. Consistent with this observation, the turnover of model granzyme A/B peptide substrates in the human CTL/NK cell lysates was not significantly reduced by brensocatib. In contrast, preincubation with brensocatib almost entirely abolished (>90%) both the cytotoxic activity of mouse CD8+ T cells and granzyme substrate turnover. Overall, our finding that the effects of DPP1 inhibition on human cytotoxic lymphocytes are attenuated in comparison to those of mice indicates that granzyme processing/activation pathways differ between mice and humans. Moreover, the in vitro data suggest that human subjects treated with reversible DPP1 inhibitors, such as brensocatib, are unlikely to experience any appreciable deficits in CTL/NK-cell-mediated immunities.

Exacerbations of bronchiectasis

Bronchiectasis presents a significant challenge due to its rising prevalence, associated economic burden and clinical heterogeneity. This review synthesises contemporary understanding and literature of bronchiectasis exacerbations, addressing the transition from stable state to exacerbations, underlining the importance of early and precise recognition, rigorous severity assessment, prompt treatment, and prevention measures, as well as emphasising the need for strategies to assess and improve early and long-term patient outcomes. The review highlights the interplay between stable state phases and exacerbations in bronchiectasis, introducing the concept of "exogenous and endogenous changes in airways homeostasis" and the "adapted island model" with a particular focus on "frequent exacerbators", a group of patients associated with specific clinical characteristics and worse outcomes. The pathophysiology of exacerbations is explored through the lens of microbial and nonmicrobial triggers and the presence and the activity of comorbidities, elaborating on the impact of both exogenous insults, such as infections and pollution, and endogenous factors such as inflammatory endotypes. Finally, the review proposes a multidisciplinary approach to care, integrating advancements in precision medicine and biomarker research, paving the way for tailored treatments that challenge the traditional antibiotic paradigm.

Proposed Etiotypes for Chronic Obstructive Pulmonary Disease: Controversial Issues

The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) revised the definition of chronic obstructive pulmonary disease (COPD) to broadly include a variety of etiologies. A new taxonomy, composed of etiotypes, aims to highlight the heterogeneity in causes and pathogenesis of COPD, allowing more personalized management strategies and emphasizing the need for targeted research to understand and manage COPD better. However, controversy arises with including some diseases under the umbrella term of COPD, as their clinical presentations and treatments differ from classical COPD, which is smoking-related. COPD due to infection (COPD-I) and COPD due to environmental exposure (COPD-P) are classifications within the new taxonomy. Some disease entities in these categories show distinct clinical features and may not benefit from conventional COPD treatments, raising questions about their classification as COPD subtypes. There is also controversy regarding whether bronchiectasis with airflow limitations should be classified as an etiotype of COPD. This article discusses controversial issues associated with the proposed etiotypes for COPD in terms of COPD-I, COPD-P, and bronchiectasis. While the updated COPD definition by GOLD 2023 is a major step towards recognizing the disease's complexity, it also raises questions about the classification of related respiratory conditions. This highlights the need for further research to improve our understanding and approach to COPD management.

Bronchiectasis in Asia: a review of current status and challenges

Recent bronchiectasis studies from large-scale multinational, multicentre registries have demonstrated that the characteristics of the disease vary according to geographic region. However, most perspectives on bronchiectasis are dominated by data from Western countries. This review intends to provide an Asian perspective on the disease, focusing on the established registries in India, Korea and China. Asian patients with bronchiectasis are less likely to show female predominance and experience exacerbations, are more likely to be younger, have milder disease, and have fewer options for guideline-recommended treatment than those living in other global regions. Furthermore, Asian bronchiectasis patients demonstrate different comorbidities, microbiological profiles and unique endophenotypes, including post-tuberculosis and dry bronchiectasis. Notably, each Asian region reveals further geographic variations and inter-patient differences. Future studies are warranted to better characterise Asian patients with bronchiectasis.

Pathophysiology and genomics of bronchiectasis

Bronchiectasis is a complex and heterogeneous inflammatory chronic respiratory disease with an unknown cause in around 30-40% of patients. The presence of airway infection together with chronic inflammation, airway mucociliary dysfunction and lung damage are key components of the vicious vortex model that better describes its pathophysiology. Although bronchiectasis research has significantly increased over the past years and different endotypes have been identified, there are still major gaps in the understanding of the pathophysiology. Genomic approaches may help to identify new endotypes, as has been shown in other chronic airway diseases, such as COPD.Different studies have started to work in this direction, and significant contributions to the understanding of the microbiome and proteome diversity have been made in bronchiectasis in recent years. However, the systematic application of omics approaches to identify new molecular insights into the pathophysiology of bronchiectasis (endotypes) is still limited compared with other respiratory diseases.Given the complexity and diversity of these technologies, this review describes the key components of the pathophysiology of bronchiectasis and how genomics can be applied to increase our knowledge, including the study of new techniques such as proteomics, metabolomics and epigenomics. Furthermore, we propose that the novel concept of trained innate immunity, which is driven by microbiome exposures leading to epigenetic modifications, can complement our current understanding of the vicious vortex. Finally, we discuss the challenges, opportunities and implications of genomics application in clinical practice for better patient stratification into new therapies.

Heterogeneity in non-cystic fibrosis bronchiectasis: insights from ASPEN trial participants

ASPEN trial participant characteristics highlight the heterogeneity of non-cystic fibrosis bronchiectasis and global variations in clinical practice patterns https://bit.ly/447XeP0.

Infection and the microbiome in bronchiectasis

Bronchiectasis is marked by bronchial dilatation, recurrent infections and significant morbidity, underpinned by a complex interplay between microbial dysbiosis and immune dysregulation. The identification of distinct endophenotypes have refined our understanding of its pathogenesis, including its heterogeneous disease mechanisms that influence treatment and prognosis responses. Next-generation sequencing (NGS) has revolutionised the way we view airway microbiology, allowing insights into the "unculturable". Understanding the bronchiectasis microbiome through targeted amplicon sequencing and/or shotgun metagenomics has provided key information on the interplay of the microbiome and host immunity, a central feature of disease progression. The rapid increase in translational and clinical studies in bronchiectasis now provides scope for the application of precision medicine and a better understanding of the efficacy of interventions aimed at restoring microbial balance and/or modulating immune responses. Holistic integration of these insights is driving an evolving paradigm shift in our understanding of bronchiectasis, which includes the critical role of the microbiome and its unique interplay with clinical, inflammatory, immunological and metabolic factors. Here, we review the current state of infection and the microbiome in bronchiectasis and provide views on the future directions in this field.

Brensocatib in non-cystic fibrosis bronchiectasis: ASPEN protocol and baseline characteristics

Introduction

Brensocatib is an investigational, oral, reversible inhibitor of dipeptidyl peptidase-1 shown to prolong time to first exacerbation in adults with bronchiectasis. Outlined here are the clinical trial design, and baseline characteristics and treatment patterns of adult patients enrolled in the phase 3 ASPEN trial (NCT04594369).

Methods

The ASPEN trial is a global study enrolling patients with a clinical history consistent with bronchiectasis (cough, chronic sputum production and/or recurrent respiratory infections), diagnosis confirmed radiologically and ≥2 exacerbations in the prior 12 months. It was designed to evaluate the impact of two brensocatib doses (10 mg and 25 mg) on exacerbation rate over a 52-week treatment period versus placebo. Comprehensive clinical data, including demographics, disease severity, lung function, Pseudomonas aeruginosa status and quality of life, were collected at baseline.

Results

1682 adults from 35 countries were randomised from December 2020 to March 2023. Mean age was 61.3 years and 64.7% were female. ∼70% had moderate-to-severe Bronchiectasis Severity Index (BSI) scores, 29.3% had ≥3 exacerbations in the prior 12 months and 35.7% were positive for P. aeruginosa. Mean BSI scores were highest in Australia/New Zealand (8.3) and lowest in Latin America (5.9). Overall, the most common aetiology was idiopathic (58.4%). In P. aeruginosa-positive versus P. aeruginosa-negative patients, lung function was lower, with greater long-term macrolide (21.5% versus 14.0%) and inhaled corticosteroid use (63.5% versus 53.9%). There was wide regional variation in long-term antibiotic use in patients with bronchiectasis and P. aeruginosa.

Discussion

ASPEN baseline characteristics and treatment profiles were representative of a global bronchiectasis population.

Biomarkers in bronchiectasis

Bronchiectasis is a heterogeneous disease with multiple aetiologies and diverse clinical features. There is a general consensus that optimal treatment requires precision medicine approaches focused on specific treatable disease characteristics, known as treatable traits. Identifying subtypes of conditions with distinct underlying biology (endotypes) depends on the identification of biomarkers that are associated with disease features, prognosis or treatment response and which can be applied in clinical practice. Bronchiectasis is a disease characterised by inflammation, infection, structural lung damage and impaired mucociliary clearance. Increasingly there are available methods to measure each of these components of the disease, revealing heterogeneous inflammatory profiles, microbiota, radiology and mucus and epithelial biology in patients with bronchiectasis. Using emerging biomarkers and omics technologies to guide treatment in bronchiectasis is a promising field of research. Here we review the most recent data on biomarkers in bronchiectasis.

Bronchiectasis

Non-cystic fibrosis bronchiectasis, a condition that remains relatively underrecognized, has garnered increasing research focus in recent years. This scientific interest has catalyzed advancements in diagnostic methodologies, enabling comprehensive clinical and molecular profiling. Such progress facilitates the development of personalized treatment strategies, marking a significant step toward precision medicine for these patients. Bronchiectasis poses significant diagnostic challenges in both clinical settings and research studies. While computed tomography (CT) remains the gold standard for diagnosis, novel alternatives are emerging. These include artificial intelligence-powered algorithms, ultra-low dose chest CT, and magnetic resonance imaging (MRI) techniques, all of which are becoming recognized as feasible diagnostic tools. The precision medicine paradigm calls for refined characterization of bronchiectasis patients by analyzing their inflammatory and molecular profiles. Research into the underlying mechanisms of inflammation and the evaluation of biomarkers such as neutrophil elastase, mucins, and antimicrobial peptides have led to the identification of distinct patient endotypes. These endotypes present variable clinical outcomes, necessitating tailored therapeutic interventions. Among these, eosinophilic bronchiectasis is notable for its prevalence and specific prognostic factors, calling for careful consideration of treatable traits. A deeper understanding of the microbiome's influence on the pathogenesis and progression of bronchiectasis has inspired a holistic approach, which considers the multibiome as an interconnected microbial network rather than treating pathogens as solitary entities. Interactome analysis therefore becomes a vital tool for pinpointing alterations during both stable phases and exacerbations. This array of innovative approaches has revolutionized the personalization of treatments, incorporating therapies such as inhaled mannitol or ARINA-1, brensocatib for anti-inflammatory purposes, and inhaled corticosteroids specifically for patients with eosinophilic bronchiectasis.