Bronchiectasis - A Clinical Review

The bronchiectasis microbiome: current understanding and treatment implications

PURPOSE OF REVIEW

Advances in DNA sequencing and analysis of the respiratory microbiome highlight its close association with bronchiectasis phenotypes, revealing fresh opportunities for diagnosis, stratification, and personalized clinical intervention. An under-recognized condition, bronchiectasis is increasingly the subject of recent large-scale, multicentre, and longitudinal clinical studies including detailed analysis of the microbiome. In this review, we summarize recent progress in our understanding of the bronchiectasis microbiome within the context of its potential use in treatment decisions.

RECENT FINDINGS

Diverse microbiome profiles exist in bronchiectasis, in line with the established disease heterogeneity including treatment response. Classical microbiology has established Pseudomonas aeruginosa and Haemophilus influenza as two microbial markers of disease, while holistic microbiome analysis has uncovered important associations with less common bacterial taxa including commensal an/or pathobiont species, including the emerging role of the fungal mycobiome, virome, and interactome. Integration of airway microbiomes with other high-dimensional biological and clinical datasets holds significant promise to determining treatable traits and mechanisms of disease related to the microbiome.

SUMMARY

The bronchiectasis microbiome is an emerging and key area of study with significant implications for understanding bronchiectasis, influencing treatment decisions and ultimately improving patient outcomes.

Pulmonary microbiology and microbiota in adults with non-cystic fibrosis bronchiectasis: a systematic review and meta-analysis

BACKGROUND

Non-cystic fibrosis bronchiectasis is associated with frequent and diverse microbial infections, yet an overall understanding of microbial presence across different disease stages is lacking.

METHODS

A meta-analysis assessed lung microbes in adults with non-CF bronchiectasis, collecting data using both culture-based and sequencing approaches through three international databases and three Chinese databases. Subgroups were categorized by disease stage: the stable group (S), the exacerbation group (E), and unclassified data consolidated into the undetermined group (U). Culture data were analysed in random-effects meta-analyses while sequencing data were processed using QIIME 2.

RESULTS

A total of 98 studies were included with data from 54,384 participants worldwide. Pseudomonas aeruginosa was the most frequently isolated bacterium (S: 26[19-34]%, E: 23[20-25]%, U: 20[16-25]%), while not specified Mycobacterium avium complex exhibited the highest mycobacterial prevalence (S: 3[1-5]%, E: 4[2-5]%, U: 15[3-27]%). Aspergillus spp. (S: 15[-10-39]%, E: 2[1-3]%, U: 10[5-15]%) and Candida spp. (S: not applicable, E: 11[2-20]%, U: 10[-8-27]%) were predominant in fungi culture with variable distributions among groups. Rhinovirus was the most commonly detected virus with varying prevalence across airway sample types rather than disease stages (S-sputum: 18[-16-53]%, S-nasopharyngeal: 4[-1-9]%, E-sputum: 22[16-29]%, E-nasopharyngeal: 6[4-8]%). Sequencing results revealed notable antibiotic persistence of Pseudomonas in 16S, and significant domination of Candida in ITS.

CONCLUSION

Our findings indicate consistent bacterial patterns throughout bronchiectasis stages in both culture and sequencing results. Viruses are extensively detected in stable patients but vary across different airway sample types. Lower bacterial diversity and higher fungal diversity may be associated with exacerbation risks.

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.

Three-dimensional imaging assisted segmentectomy in the treatment of localized bronchiectasis: a retrospective analysis

BACKGROUND

Surgical treatment is crucial in managing bronchiectasis. Segmentectomy, although a complex procedure, has become more feasible with advancements in thin-slice CT and three-dimensional imaging. These technologies enhance preoperative anatomical understanding and surgical planning. This study aims to demonstrate the viability of using three-dimensional imaging assistance for treating localized bronchiectasis through segmentectomy.

METHODS

From 2021 to 2023, a total of 34 patients with bronchiectasis underwent segmentectomy. We collected and then analyzed potential factors including general conditions, preoperative clinical symptoms, surgical procedures, length of postoperative hospital stay, incidence of postoperative complications and postoperative follow-ups.

RESULTS

Of the 34 surgical patients, 8 were men and 26 were women, resulting in a total of 34 operations. The average surgical time for segmentectomy was 157.7 ± 63.4 min. The average intraoperative blood loss was 115.9 ± 107.4 ml. Postoperative tube placement lasted an average of 6.5 ± 2.4 days, with an average drainage volume of 724.7 ± 500.9 ml. The average hospital stay was 8.2 ± 3.4 days. Among these patients, 2 developed pneumothorax and 2 experienced air leaks. Additionally, 4 patients developed pneumonia postoperatively. Over an average follow-up period of 14.3 months, most patients showed symptom improvement, with only two cases of recurrence.

CONCLUSIONS

Segmentectomy has acceptable postoperative morbidity, mortality, and outcomes. Therefore, segmentectomy is a viable option for the treatment of localized bronchiectasis.

Baseline characteristics of patients in the Chinese Bronchiectasis Registry (BE-China): a multicentre prospective cohort study

BACKGROUND

Bronchiectasis is a disease with a global impact, but most published data come from high-income countries. We aimed to describe the clinical characteristics of patients with bronchiectasis in China.

METHODS

The Chinese Bronchiectasis Registry (BE-China) is a prospective, observational cohort enrolling patients from 111 hospitals in China. Data on demographics, comorbidities, and aetiological testing results were collected from adult patients with bronchiectasis at baseline and annual follow-up. Patients who met the inclusion criteria (age ≥18 years; received chest high-resolution CT in the past year showing bronchiectasis affecting one or more lung lobes; and clinical history consistent with bronchiectasis, including chronic cough, daily sputum production, and history of exacerbations) were included. Patients with known cystic fibrosis were excluded. To investigate variations according to different economic regions, two groups were compared based on whether per capita disposable income of residents was greater than US$5553. Clinical characteristics were compared with the European (EMBARC) registry and other national registries.

FINDINGS

Between Jan 10, 2020, and March 31, 2024, 10 324 patients from 97 centres were included in the study. Among 9501 participants with available data, the most common cause of bronchiectasis was post-infective disease (4101 [43·2%] patients), followed by idiopathic (2809 [29·6%] patients). 6676 (70·0%) of 9541 patients with available data had at least one exacerbation in the year before enrolment and 5427 (57·2%) of 9489 patients with available data were hospitalised at least once due to exacerbations. Treatments commonly used in high-income countries, such as inhaled antibiotics and macrolides, were infrequently used in China. Implementation of airway clearance in China was scarce, with only 1177 (12·2%) of 9647 patients having used at least one method of airway clearance. Compared with upper-middle-income regions, patients from lower-middle-income regions were younger (61·0 years [SD 14·0] vs 63·9 years [14·2]) with a higher proportion of pulmonary comorbidities (521 [17·8%] of 2922 patients vs 639 [8·6%] of 7402 with chronic obstructive pulmonary disease and 194 [6·6%] of 2922 patients vs 364 [4·9%] of 7402 patients with asthma), a higher tuberculosis burden (442 [16·0%] of 2768 patients vs 715 [10·6%] of 6733 patients), more severe radiological involvement (1160 [42·4%] of 2736 patients vs 2415 [35·4%] of 6816 patients with cystic bronchiectasis), more exacerbations (median 1·4 [IQR 0-2] in both groups; mean 1·4 [SD 1·6] vs 1·2 [1·4] in the previous year) and hospitalisations (1662 [60·6%] of 2743 patients vs 3765 [55·8%] of 6746 patients hospitalised at least once in the previous year), and poorer quality of life (median 57·4 [IQR 53·5-63·1] vs 58·7 [54·8-64·8] assessed by the Bronchiectasis Health Questionnaire).

INTERPRETATION

The clinical characteristics of patients with bronchiectasis in China show differences compared with cohorts in Europe and India. Bronchiectasis is more severe with a higher burden of exacerbations in lower-income regions. The management of patients with bronchiectasis in China urgently needs standardisation and improvement.

FUNDING

National Natural Science Foundation of China, Innovation Program of the Shanghai Municipal Education Commission, Program of the Shanghai Municipal Science and Technology Commission, and Program of the Shanghai Shenkang Development Center.

TRANSLATION

For the Chinese translation of the abstract see Supplementary Materials section.

Pregnancy zone protein, a potential research target in multiple diseases

Pregnancy zone protein (PZP) is an antiprotease-resistant immunosuppressant belonging to the α-macroglobulin (αM) protein family. PZP is secreted by the liver and was found to be upregulated in plasma during pregnancy. α-2-macroglobulin (Α2M) shares 71 % serial homology with PZP, but low PZP levels do not lead to increased A2M levels in pregnancy. PZP can interact with several factors such as low-density lipoprotein receptor-associated protein (LRP), transforming growth factor-β (TGF-β), 78 kDa glucose-regulated protein (GRP78), and glycoside A (GdA). PZP is involved in the development of glycolipid metabolism disorders, bronchiectasis, Alzheimer's disease (AD), rheumatoid arthritis (RA), myocardial infarction (MI) and inflammatory bowel disease (IBD). PZP is also associated with the progression of tumorigenesis such as breast cancer (BC), homologyepatocellular carcinoma (HCC), lung adenocarcinoma (LAC), and colorectal cancer (CRC). Therefore, this review analyzes the role of PZP in pathophysiology of various diseases.

Causative diseases of bloody sputum and hemoptysis in respiratory clinics in Japan

BACKGROUND

No previous studies have compared respiratory clinics and respiratory specialized facilities regarding causative diseases for bloody sputum and hemoptysis in Japan.

METHODS

We retrospectively compared causative diseases for bloody sputum and hemoptysis between 3 respiratory clinics (clinic group) and 7 departments of respiratory medicine at hospitals (hospital group) in Japan.

RESULTS

We collected data from 231 patients (median age, 51 years; age range, 24-96 years; 109 men (47.2%)) in the clinic group and 556 patients (median age, 73 years; age range, 21-98 years; 302 men (54.3%)) in the hospital group. In the former group, the main causative disease was acute bronchitis (91 patients, 39.4%), acute upper respiratory tract infection (34 patients, 14.7%), and bronchiectasis (BE) (29 patients, 12.6%). In the latter group, the main causative diseases were BE (102 patients, 18.3%), lung cancer (97 patients, 17.4%), and non-tuberculous mycobacterial disease (NTM) (89 patients, 16%). In particular, in patients ≥60 years old, BE was an important causative disease for bloody sputum and hemoptysis in both groups.

CONCLUSIONS

The present study is the first to compare respiratory clinics and respiratory specialized facilities. Depending on the facility in which the patient is examined, lung cancer, BE, and NTM were identified as diseases requiring special attention as causes of bloody sputum and hemoptysis.

Clinical Benefits of Targeting Treatable Traits in Asthma and Chronic Obstructive Pulmonary Disease

Asthma and chronic obstructive pulmonary disease (COPD) have long been debated regarding their similarities and differences in clinical presentation and pathology. There has also been a discussion about how common therapeutics should be used differently for each disease. Traditionally, a "one size fits all" stepwise treatment has been chosen based on the severity of each case after categorizing the diseases, such as asthma or COPD. However, recently, the need for a precise approach for the treatment of individual patients beyond the disease category has been emphasized, especially in severe cases. To achieve precise personalized therapy, it has become necessary to focus on the individual phenotypes and underlying causal molecular mechanisms (endotypes) and to identify key therapeutic targets, which are called treatable traits. This review discusses the evidence for the importance of identifying treatable traits and therapeutic strategies based on the broader perspective of chronic obstructive airway disease rather than on individual diseases such as asthma or COPD.

Association between preserved ratio impaired spirometry and 1-year clinical outcomes in patients with bronchiectasis patients: A cohort study

BACKGROUND

Preserved Ratio Impaired Spirometry (PRISm) (defined as the ratio of forced expired volume in the first second to forced vital capacity (FEV1/FVC) greater than 0·70 with a FEV1 of less than 80% predicted) is associated with a higher risk of hospitalizations and mortality in the general population. However, less is known about whether PRISm is associated with adverse clinical outcomes in patients with bronchiectasis. We aimed to investigate whether PRISm is associated with adverse clinical outcomes in bronchiectasis patients.

METHODS

We performed a retrospective cohort study with inpatients admitted with acute exacerbations of bronchiectasis between January 2017 and January 2022. Clinical data including anthropometry, spirometry, laboratory, etiological and radiologic variables were collected. Patients were divided into the normal spirometry group, the PRISm group and the obstructive spirometry group. All patients were followed up for 1 year. The primary outcome was readmission of bronchiectasis at 1 year.

RESULTS

Of 487 bronchiectasis patients, we found 142 (29.2%) had normal spirometry, 67 (13.8%) had PRISm and 278 (57.1%) had obstructive spirometry. Patients with obstructive spirometry were more likely to be male and to smoke, had higher fibrinogen values and more lobes affected. Patients with PRISm (HR 1.929, 95% CI 1.049 to 3.546) and obstructive spirometry (HR 2.406, 95%CI 1.506 to 3.845) had a higher risk of readmissions compared with those with normal spirometry after adjustment for potential confounders.

CONCLUSIONS

PRISm was associated with significant increased risk for readmissions in patients with bronchiectasis compared with normal spirometry, which should receive special attention.

Real-world disease burden, mortality, and healthcare resource utilization associated with bronchiectasis

OBJECTIVES

To assess real-world survival and healthcare resource utilization (HCRU) in US patients with non-cystic fibrosis bronchiectasis (NCFBE).

METHODS

This retrospective analysis, using data from the STATinMED RWD Insights database from Jan 2015-Oct 2022, included adults with NCFBE (from Jan 2015-Oct 2021) and non-NCFBE comparators (from Jan 2015-Aug 2020); baseline characteristics were balanced by inverse probability treatment weighting. Outcomes included survival through end of study. HCRU was assessed over 12 months.

RESULTS

117,718 patients with NCFBE and 306,678 comparators were included. Patients with NCFBE had a 77% higher risk of death than comparators (hazard ratio [HR] 1.77 [95% CI 1.74-1.80]). Risk of death was higher among patients aged ≥65 years (vs 18-34 years; HR 11.03 [95% CI 10.36-11.74]), among Black patients (vs White; HR 1.53 [95% CI 1.50-1.55]), and among patients with comorbid COPD (HR 1.42 [95% CI 1.40-1.44]). Patients with NCFBE incurred higher all-cause and respiratory-related HCRU than comparators for outpatient office, outpatient hospital, emergency department (ED), inpatient and respiratory-related pulmonologist visits (all p < .0001); HCRU increased with exacerbations.

CONCLUSIONS

Patients with NCFBE have high mortality burden and incur high HCRU, both of which are further increased with exacerbations. Prevention and delay of exacerbations are key areas for improvement of disease management.

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.

Infections, autoimmunity and immunodeficiencies are the leading etiologies of non-cystic fibrosis bronchiectasis in adults from the southwest of Colombia

INTRODUCTION

Non-cystic fibrosis bronchiectasis is a complex medical condition with multiple etiologies, characterized by chronic productive cough and radiologic evidence of airway lumen dilation and wall thickening. Associated exacerbations and declining lung function contribute to increasing disability and mortality. There are no data about the prevalence of non-cystic fibrosis bronchiectasis etiologies in the Colombian population.

OBJECTIVE

To investigate non-cystic fibrosis bronchiectasis etiology and clinical characteristics in adults evaluated in the southwest of Colombia.

MATERIALS AND METHODS

We conducted a cross-sectional, non-interventional study. Subjects diagnosed with non-cystic fibrosis bronchiectasis were referred to by their healthcare providers and then enrolled between October 2018 and April 2021. Medical records and radiological studies were evaluated. Participants underwent laboratory tests, including complete blood count, serum immunoglobulin levels, and, in some cases, additional tests.

RESULTS

We included 161 subjects. The average age was 50 years old, and 59% were females. Bronchiectasis etiology was identified in 84.6% of the cases. Postinfectious (34.6%) and immune disorders (25.3%), represented by autoimmunity (13.6%) and immunodeficiency (11.7%), were the leading causes. Gender differences were noted in autoimmune (females: 18.8% versus males: 6.1%, p = 0.021) and immunodeficiency-related bronchiectasis (males: 21.2% versus females 5.2%, p = 0.002). Immunodeficiencies-associated bronchiectases were more frequent in subjects under 50 years of age, while chronic obstructive pulmonary disease-associated bronchiectases were common in subjects over 50 years of age.

DISCUSSION

The etiologies of non-cystic fibrosis bronchiectasis in Colombia are diverse, exhibiting notable differences from other global regions. Serum immunoglobulin levels and clinical immunologist consultation should be prioritized in diagnosing patients with unclear bronchiectasis etiology, particularly those with recurrent sinopulmonary infections.

Risk factors for readmission within one year after acute exacerbations of bronchiectasis in a Chinese tertiary hospital: a retrospective cohort study

BACKGROUND

Frequent exacerbations of bronchiectasis lead to poor quality of life, impaired lung function, and higher mortality rates. This study aims to evaluate the risk factors associated with readmission within one year due to acute exacerbation of bronchiectasis (AEB).

METHODS

A retrospective cohort study was performed on 260 patients with bronchiectasis who were hospitalized in the respiratory and critical care department of a tertiary hospital in China. Univariate and multivariate Cox analyses were used to evaluate the risk factors for readmission within one year.

RESULTS

Readmission within one year was found in 44.6% of 260 patients hospitalized with acute exacerbation of bronchiectasis. The risk factors associated with readmission included age over 65 years (HR = 3.66; 95% CI: 2.30 to 5.85), BMI < 18.5 kg/m2 (HR = 1.71; 95% CI: 1.16 to 2.51), respiratory intensive care unit (RICU) stay during admission (HR = 2.06, 95% CI: 1.16-3.67), involvement of 3 or more lobes on chest high-resolution computed tomography (HRCT) (HR = 1.85; 95% CI, 1.22 to 2.80), chronic Pseudomonas aeruginosa (PA) colonization (HR = 2.29; 95% CI: 1.54 to 3.38), and positive sputum culture results within 24 h after admission (HR = 1.93; 95% CI: 1.27 to 2.94). Long-term oral antibiotics use after discharge was associated with decreased hazard of readmission (HR = 0.34; 95% CI: 0.20 to 0.59).

CONCLUSIONS

Patients with bronchiectasis have a high rate of readmission, which is linked to varieties of risk factors, and identifying these risk factors is importance for effectively managing patients with bronchiectasis.

Prevalence and Clinical Implications of Pulmonary Vein Stenosis in Bronchiectasis: A 3D Reconstruction CT Study

BACKGROUND

Recent studies on bronchiectasis have revealed significant structural abnormalities and pathophysiological changes. However, there is limited research focused on pulmonary venous variability and congenital variation. Through our surgical observations, we noted that coarctation of pulmonary veins and atrophied lung volume are relatively common in bronchiectasis patients. Therefore, we conducted a retrospective study to explore pulmonary venous variation and secondary manifestations in bronchiectasis cases, utilizing 3D reconstruction software (Mimics Innovation Suite 21.0, Materialise Dental, Leuven, Belgium) to draw conclusions supported by statistical evidence.

METHOD

This retrospective study included patients with bronchiectasis and healthy individuals who underwent CT examinations at Beijing Chao-Yang Hospital between January 2017 and July 2023. Chest CT data were reconstructed using Materialise Mimics. Pulmonary veins and lung lobes were segmented from surrounding tissue based on an appropriate threshold determined by local grey values and image gradients. Subsequently, venous cross-sectional areas and lung volumes were measured for statistical analysis.

RESULT

CT data from 174 inpatients with bronchiectasis and 75 cases from the health examination center were included. Three-dimensional reconstruction data revealed a significant reduction in cross-sectional areas of pulmonary veins in the left lower lobe (p < 0.001), the right lower lobe (p = 0.030), and the right middle lobe (p = 0.009) of bronchiectasis patients. Subgroup analyses indicated that approximately 73.5% of localized cases of the left lower lobe exhibited pulmonary vein stenosis, while in the diffuse group, this proportion was only 52.6%. Furthermore, the cross-sectional area of pulmonary veins had a gradually decreasing trend, based on a small sample. Lung function tests showed significant reductions in FEV1, FVC, and FEV1% in bronchiectasis patients, attributed to the loss of lung volume in the left lower lobe, which accounted for 60.9% of the included sample.

CONCLUSIONS

Our recent findings suggest that pulmonary venous stenosis is a common variation in bronchiectasis and is often observed concurrently with reduced lung volume, particularly affecting the left lower lobe. Moreover, localized cases are more likely to suffer from pulmonary venous stenosis, with an ambiguous downtrend as the disease progresses. In conclusion, increased attention to pulmonary venous variation in bronchiectasis is warranted, and exploring new therapies to intervene in the early stages or alleviate obstruction may be beneficial.

Chest X-Ray Features in 130 Patients with Bronchiectasis

Background/Objectives: The prevalence of bronchiectasis is increasing globally, and early detection using chest imaging has been encouraged to improve its prognosis. However, the sensitivity of a chest X-ray as a screening tool remains unclear. This study examined the chest X-ray features predictive of bronchiectasis. Methods: We retrospectively reviewed the chest X-rays of patients with bronchiectasis diagnosed using high-resolution computed tomography who visited our institute from January 2013 to March 2020. Patients with cardiac pacemakers, lung cancer, and interstitial pneumonia, which might bias the detection of bronchiectasis, were excluded. Two respiratory physicians independently determined the presence or absence of potential features reflecting bronchiectasis, including a vague cardiac silhouette on chest X-rays. Results: The study enrolled 130 patients, including 72 women (55.4%), with a mean age of 72 years. The features observed on chest X-rays included granular shadows (88.5%, n = 115), vague cardiac silhouettes (48.5%, n = 64), nodular shadows (45.4%, n = 59), a tram-track appearance (35.4%, n = 46), pleural thickening (26.9%, n = 35), vague diaphragm silhouettes (25.4%, n = 33), and a ring sign (24.6%, n = 32). The kappa values for these features were 0.271, 0.344, 0.646, 0.256, 0.312, 0.514, and 0.376, respectively. Conclusions: Although traditional chest X-ray features believed to reflect bronchiectasis, such as the tram-track appearance or ring sign, were not frequently seen, vague cardiac silhouettes and granular shadows had high positivity rates, indicating their potential utility for bronchiectasis screening. However, the interobserver concordance rates were unsatisfactory.

Impact of Antipseudomonal Antibiotics in Patients with Bronchiectasis Who Experienced Exacerbation or Developed Pneumonia: A Nationwide Study in Japan

Background/Objectives: Although chronic infection by Pseudomonas aeruginosa among patients with bronchiectasis is associated with poor prognosis, the impact of antibiotics with P. aeruginosa coverage in patients with bronchiectasis who experienced bacterial pneumonia or exacerbation of bronchiectasis has not been fully investigated. Methods: This study targeted patients with bronchiectasis who were admitted to hospitals because of bacterial pneumonia or exacerbation of bronchiectasis between April 2018 and March 2020 using a national inpatient database in Japan. The association of antipseudomonal antibiotic treatment with in-hospital mortality was assessed after propensity score matching to adjust the patients' backgrounds. Results: In total, 4943 patients with bacterial pneumonia and 1914 patients with exacerbation of bronchiectasis were included in this study. The in-hospital mortality rate did not differ between patients who did and did not receive antipseudomonal agents among patients with bacterial pneumonia (9.0% [185/2045] vs. 7.4% [151/2045]; p = 0.053) and those with exacerbation of bronchiectasis (5.2% [42/803] vs. 4.1% [33/803] group; p = 0.287). Conclusions: The use of antibiotics covering P. aeruginosa does not apparently improve prognosis in patients with bacterial pneumonia or exacerbation of bronchiectasis. A prospective study focusing on the impact of antibiotics covering P. aeruginosa among patients with bronchiectasis in whom P. aeruginosa is isolated is required.

Association of asthma and bronchiectasis: Mendelian randomization analyses and observational study

BACKGROUND

Previous studies have demonstrated that asthma is closely associated with bronchiectasis, however, the causal relationship between asthma and bronchiectasis has not been investigated in depth. Therefore, this study aims to explore the causal relationship and to identify potential factors that mediate between these two diseases.

METHOD

All the necessary summarized information were obtained from publicly available genome-wide association study (GWAS). Two-sample Mendelian randomization (two-sample MR) was employed to explore the causal relationship between asthma and bronchiectasis, with an additional dataset used for validation. Heterogeneity and pleiotropy analyses were utilized to verify the robustness of the results. Subsequently, mediation MR analyses were performed to identify potential mediating factors. Lastly, a retrospective observational study was conducted to validate the findings.

RESULT

Preliminary inverse-variance weighted (IVW) results indicated there was a causal effect of asthma on bronchiectasis (odds ratio [OR] = 1.228, 95% confidence interval [CI]: 1.077-1.400, P = 0.002). Repetition validation yielded a consistent result. Mediation MR analysis demonstrated that the presence of nasal polyps (OR = 1.063, 95% CI: 1.015-1.113, mediation ratio = 30.492%, P = 0.009), acute sinusitis (OR = 1.062, 95% CI: 1.009-1.118, mediation ratio = 30.157%, P = 0.018), chronic sinusitis (OR = 1.085, 95% CI: 1.024-1.150, mediation ratio = 40.677%, P = 0.005), and peripheral eosinophil counts (OR = 1.013, 95% CI: 1.000-1.026, mediation ratio = 6.514%, P = 0.042) served as significant mediators in the occurrence and development of bronchiectasis induced by asthma. Furthermore, a retrospective observational study observed that bronchiectasis patients with asthma had a higher prevalence of sinusitis (5.043% vs 2.971%, P < 0.001), nasal polyps (0.536% vs 0.152%, P < 0.001), and rhinitis (13.197% vs 1.860%, P < 0.001). The ratio (1.950 (0.500, 5.600) vs 1.500 (0.500, 2.600), P = 0.006) and counts (0.125 (0.040, 0.363) vs 0.090 (0.030, 0.160), P < 0.001) of peripheral blood eosinophils were also elevated in bronchiectasis patients with asthma.

CONCLUSION

The MR analysis uncovered a notable genetic association between asthma and bronchiectasis, which was partially mediated by sinusitis, nasal polyps, and eosinophils. A subsequent retrospective study provided further evidence by demonstrating that bronchiectasis patients with asthma had a higher prevalence of sinusitis, nasal polyps, an elevated proportion of eosinophils, and higher eosinophil counts.

Autologous transplantation of P63+ lung progenitor cells in patients with bronchiectasis: A randomized, single-blind, controlled trial

Non-cystic fibrosis bronchiectasis is a progressive respiratory disease with limited treatment options, prompting the exploration of regenerative therapies. This study investigates the safety and efficacy of autologous P63+ progenitor cell transplantation in a randomized, single-blind, controlled, phase 1/2 trial. Thirty-seven patients receive bronchoscopic airway clearance (B-ACT) (n = 19) or B-ACT plus P63+ progenitor cells (n = 18). Results show that compared to the control group, the change in DLCO levels from baseline to 24 weeks post therapy is significantly higher in the cell treatment group (p value = 0.039). Furthermore, the patients in the cell treatment group demonstrate significantly reduced lung damaged area, improved SGRQ score, and ameliorated BSI and FACED scores within 4-12 weeks post therapy. Transcriptomic analysis reveals that progenitor cells with higher expression of P63 gene have better therapeutic efficacy. These findings suggest that P63+ progenitor cells may offer a promising therapeutic approach for bronchiectasis. This study was registered at ClinicalTrials.gov(NCT03655808).

Chronic bronchiectasis and celiac disease: An uncommon association and the importance of a comprehensive diagnostic approach

In unexplained bronchiectasis, particularly with concurrent gastrointestinal symptoms or evidence of malabsorption, consider celiac disease as a potential underlying condition. Early diagnosis and a multidisciplinary approach integrating both respiratory and gastrointestinal management can significantly enhance patient outcomes.

Associations Between Chronic Rhinosinusitis and the Development of Non-Cystic Fibrosis Bronchiectasis

BACKGROUND

Studies have shown an association between chronic rhinosinusitis (CRS) and non-cystic fibrosis (CF) bronchiectasis.

OBJECTIVE

We aimed to determine whether CRS increases the risk of developing non-CF bronchiectasis.

METHODS

A retrospective analysis was conducted utilizing electronic medical records from an academic center. Patients with CRS without bronchiectasis, with at least 1 chest computed tomography (CT) scan performed after the diagnosis of CRS, were identified between January 2006 and December 2015. Charts were reviewed until May 2022. The control group was age-, sex-, and race-matched, and included patients without CRS, asthma, or chronic obstructive pulmonary disease (COPD) who had at least 1 chest CT scan. Bronchiectasis was identified by chest CT radiology reports. The odds of developing bronchiectasis were analyzed in patients with CRS without asthma or COPD (cohort 1) and patients with CRS with asthma or COPD (cohort 2).

RESULTS

The odds of developing bronchiectasis were significantly higher in patients with CRS (139 of 1,594; 8.7%) than in patients in the control group (443 of 7,992; 5.5%; odds ratio OR 1.63; 95% confidence interval [95% CI] 1.34-1.99). Furthermore, the odds of developing bronchiectasis were higher in cohort 1 (63 of 863; 7.3%; OR 1.34; 05% CI 1.02-1.76) and cohort 2 (76/ of 731; 10.4%; OR 1.98; 95% CI 1.53-2.55) versus the control group. After adjusting for confounding diseases, the association was attenuated in cohort 1 (OR 1.22; 95% CI 0.92-1.61) but remained significant in cohort 2 (OR 1.78; 95% CI 1.37-2.31).

CONCLUSIONS

The CRS is associated with the future development of non-CF bronchiectasis. Patients with CRS, especially those with asthma or COPD, have a higher likelihood of developing bronchiectasis than patients without CRS.

Nebulized hypertonic saline and positive expiratory pressure device use in patients with bronchiectasis: Analysis from the United States Bronchiectasis and NTM research registry

BACKGROUND

Nebulized Hypertonic saline (HS) and positive expiratory pressure device (PEP) are often used in patients with bronchiectasis. We sought to describe the clinical characteristics in patients using HS and PEP, utilizing a large national database registry.

METHODS

Data from the US Bronchiectasis and NTM Research Registry were used in this study. Patients with a diagnosis of bronchiectasis were included. Eligible patients were assigned to one of four mutually exclusive groups: HS only, PEP only, HS & PEP, or no airway clearance or mucoactive agent. Descriptive statistics were computed for the overall study population and stratified by the four groups. One-way ANOVA and chi-square tests were used to test the difference in the means in continuous variables and the association between categorical variables (respectively) across the four groups.

RESULTS

A total of 2195 patients were included. Of those with bronchiectasis and a productive cough, a greater number of patients utilized HS only vs PEP only (17.5 % vs 9.1 %, p < 0.001). Similar association was found in those with Pseudomonas aeruginosa (22.3 % HS only vs 6.5 % PEP only, p < 0.001). There was a higher number of patients who used HS and PEP therapy in combination vs PEP therapy alone (25.0 % vs 9.1 %, p = 0.002), in those with a productive cough.

CONCLUSIONS

In patients with bronchiectasis and a productive cough or Pseudomonas aeruginosa, HS is used more often than PEP alone. There is a need for further analysis to compare these two modalities and explore the factors influencing their utilization.

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).

Long-Term High-Flow Nasal Therapy in Patients with Bronchiectasis of Different Severity: A Retrospective Cohort Study

Background/Objectives: High-flow nasal therapy (HFNT) has been shown to reduce exacerbations of COPD and some evidence displays benefits in non-cystic fibrosis bronchiectasis (NCFB) patients. The present study aimed to compare the effectiveness of 12 months of home HFNT on the annual exacerbation rate between mild/moderate and severe NCFB patients, classified by the bronchiectasis severity index (BSI). Secondary outcomes were the evaluation of the dyspnea, pulmonary function, and sputum cultures in both groups. Methods: The study population included NCFB adult patients, with at least one severe exacerbation in the previous year on optimized therapy. NCFB exacerbations, dyspnea (mMRC score), pulmonary function test, and sputum cultures were assessed at baseline and after 12 months of HFNT. Results: A total of 86 NCFB patients were enrolled: 36 in the mild/moderate (BSI < 9) and 50 in the severe (BSI ≥ 9) group. A significant improvement in the annual exacerbation rate was found in both BSI ≥ 9 (p < 0.0001) and BSI < 9 cohorts (p < 0.0001), with a between-group difference of -1 (95% CI: -2 to 0) exacerbations per year (p = 0.0209). The change in the annual exacerbation rate was significantly correlated with BSI (ρ = -0.26, p = 0.0151) and with HFNT daily use (ρ = -0.22, p = 0.0460). The mMRC score significantly improved by -2 points (95% CI: -2 to -1) after treatment in both groups (p < 0.0001). The percentage of patients with P. aeruginosa colonization decreased from 34.9% to 27.9%. Conclusions: Long-term HFNT reduces the annual exacerbation rate in NCFB patients and its effectiveness increases alongside disease severity and daily use of HFNT.

Prevalence of bronchiectasis in adults: a meta-analysis

BACKGROUND

Bronchiectasis, once considered an orphan disease, is receiving attention globally owing to its increasing prevalence, healthcare burden, and associated morbidity. However, the prevalence of bronchiectasis is unclear. This meta-analysis estimates the prevalence of bronchiectasis in adults, providing a valuable reference for future research.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were searched from inception to May 31, 2024 for studies reporting the prevalence of bronchiectasis. Study selection, data extraction, and overall analysis of risk of the retrieved studies were conducted independently by two authors. The tool for assessing the risk of bias in prevalence studies was used to evaluate overall risk. Stata software (version 15.1) was used to performed the meta-analysis. Subgroup and sensitivity analyses were conducted to identify the source of heterogeneity. Funnel plots combined with Egger's test were used to detect publication bias.

RESULTS

The pooled prevalence of bronchiectasis in adults from 15 studies covering 437,851,478 individuals was 680 per 100,000 (95% CI: 634-727 per 100,000). Subgroup analysis showed that the prevalence of bronchiectasis in the United States, Korea, and China was 478 per 100,000 (95% CI: 367-588 per 100,000), 886 per 100,000 (95% CI: 778-993 per 100,000), and 759 per 100,000 (95% CI: 35-2399 per 100,000), respectively; 467 per 100,000 (95% CI: 416-518 per 100,000) in males and 535 per 100,000 (95% CI: 477-592 per 100,000) in females; 3958 per 100,000 (95% CI: 117-12637 per 100,000), 4677 per 100,000 (95% CI: 427-8928 per 100,000), and 3630 per 100,000 (95% CI: 158-7103 per 100,000) among never-smokers, ever-smokers, and current smokers, respectively; 430 per 100,000 (95% CI: 411-450 per 100,000), 380 per 100,000 (95% CI: 374-386 per 100,000), and 351 per 100,000 (95% CI: 342-360 per 100,000) among individuals with body mass index<18.5, 18.5-24.9, and ≥ 25, respectively. Sixteen comorbidities were evaluated in patients with bronchiectasis, revealing a high rate.

CONCLUSION

Bronchiectasis is not a rare disease and requires more attention from scientific researchers.

TRIAL REGISTRATION

The protocol for this review was registered with PROSPERO: CRD42023409216. Registered 26 June 2023.

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.

Metabolic regulation of neutrophil functions in homeostasis and diseases

Neutrophils are the most abundant leukocytes in humans and play a role in the innate immune response by being the first cells attracted to the site of infection. While early studies presented neutrophils as almost exclusively glycolytic cells, recent advances show that these cells use several metabolic pathways other than glycolysis, such as the pentose phosphate pathway, oxidative phosphorylation, fatty acid oxidation, and glutaminolysis, which they modulate to perform their functions. Metabolism shifts from fatty acid oxidation-mediated mitochondrial respiration in immature neutrophils to glycolysis in mature neutrophils. Tissue environments largely influence neutrophil metabolism according to nutrient sources, inflammatory mediators, and oxygen availability. Inhibition of metabolic pathways in neutrophils results in impairment of certain effector functions, such as NETosis, chemotaxis, degranulation, and reactive oxygen species generation. Alteration of these neutrophil functions is implicated in certain human diseases, such as antiphospholipid syndrome, coronavirus disease 2019, and bronchiectasis. Metabolic regulators such as AMPK, HIF-1α, mTOR, and Arf6 are linked to neutrophil metabolism and function and could potentially be targeted for the treatment of diseases associated with neutrophil dysfunction. This review details the effects of alterations in neutrophil metabolism on the effector functions of these cells.

Adjunctive N-Acetylcysteine and Lung Function in Pulmonary Tuberculosis

BACKGROUND

Tuberculosis remains a global health concern, and half of cured patients have permanent lung injury. N-acetylcysteine (NAC) has shown beneficial antimicrobial, antioxidant, and immunomodulatory effects in preclinical tuberculosis models. We examined its effects on tuberculosis treatment outcomes.

METHODS

This prospective, randomized, controlled trial nested within the TB SEQUEL cohort study enrolled 140 adults with moderate or far-advanced tuberculosis. Participants were randomly assigned 1:1 to standard therapy with or without 1200 mg of oral NAC twice daily for days 1 to 112. Clinical evaluations, sputum culture, and spirometry were performed at specified intervals through day 168, after which participants returned to the TB SEQUEL cohort. The primary outcome was culture conversion. Secondary outcomes included whole-blood glutathione levels and lung function.

RESULTS

Participants were predominantly young, male, and human immunodeficiency virus 1-negative and had heavy sputum Mycobacterium tuberculosis (MTB) infection burdens. NAC increased glutathione levels (NAC × day interaction, 8.48; 95% confidence interval [CI], 1.93 to 15.02) but did not increase stable culture conversion (hazard ratio, 0.84; 95% CI, 0.59 to 1.20; P=0.33). NAC treatment was associated with improved recovery of lung function (NAC × month, 0.49 [95% CI, 0.02 to 0.95] and 0.42 [95% CI, -0.06 to 0.91] for forced vital capacity and forced expiratory volume in the first second, respectively, as percentages of predicted values). The effects of NAC on lung function were greatest in participants with severe baseline lung impairment and appeared to persist beyond the period of NAC administration. Rates of serious or grade 3 to 4 nonserious adverse events did not differ between the groups.

CONCLUSIONS

Despite increasing whole-blood glutathione levels, NAC did not affect eradication of MTB infection in adults with pulmonary tuberculosis that was moderate to far advanced. Secondary outcomes of lung function showed changes that merit further investigation. (Funded by TB SEQUEL grant 01KA1613 of the German Ministry for Education and Research, the Health Africa Project, and the German Center for Infection Research; ClinicalTrials.gov number, NCT03702738.).

Quantitative analysis of interstitial lung abnormalities on computed tomography to predict symptomatic radiation pneumonitis after lung stereotactic body radiotherapy

BACKGROUND AND PURPOSE

Symptomatic radiation pneumonitis (SRP) is a complication of thoracic stereotactic body radiotherapy (SBRT). As visual assessments pose limitations, artificial intelligence-based quantitative computed tomography image analysis software (AIQCT) may help predict SRP risk. We aimed to evaluate high-resolution computed tomography (HRCT) images with AIQCT to develop a predictive model for SRP.

MATERIALS AND METHODS

AIQCT automatically labelled HRCT images of patients treated with SBRT for stage I lung cancer according to lung parenchymal pattern. Quantitative data including the volume and mean dose (Dmean) were obtained for reticulation + honeycombing (Ret + HC), consolidation + ground-glass opacities, bronchi (Br), and normal lungs (NL). After associations between AIQCT's quantified metrics and SRP were investigated, we developed a predictive model using recursive partitioning analysis (RPA) for the training cohort and assessed its reproducibility with the testing cohort.

RESULTS

Overall, 26 of 207 patients developed SRP. There were significant between-group differences in the Ret + HC, Br-volume, and NL-Dmean in patients with and without SRP. RPA identified the following risk groups: NL-Dmean ≥ 6.6 Gy (high-risk, n = 8), NL-Dmean < 6.6 Gy and Br-volume ≥ 2.5 % (intermediate-risk, n = 13), and NL-Dmean < 6.6 Gy and Br-volume < 2.5 % (low-risk, n = 133). The incidences of SRP in these groups within the training cohort were 62.5, 38.4, and 7.5 %; and in the testing cohort 50.0, 27.3, and 5.0 %, respectively.

CONCLUSION

AIQCT identified CT features associated with SRP. A predictive model for SRP was proposed based on AI-detected Br-volume and the NL-Dmean.

Real-world treatment patterns, health care resource utilization, and costs in a US Medicare population with bronchiectasis

BACKGROUND

Bronchiectasis carries a significant economic burden with high health care expenditures associated with frequent hospitalizations, physician visits, and treatments, including oral and intravenous antibiotics for repeated lung infections, airway-clearance therapy, and oxygen administration. Bronchiectasis exacerbations can contribute to this burden.

OBJECTIVE

To estimate US health care resource utilization (HCRU) and costs associated with bronchiectasis and with bronchiectasis exacerbations.

METHODS

This retrospective study used the 100% Medicare Fee-for-Service database (January 2014 to December 2020) to compare HCRU and costs among patients with bronchiectasis with those of patients without bronchiectasis (controls). For patients with bronchiectasis, the index date was a randomly selected bronchiectasis claim after more than 1 year of disease history and, for controls, a claim closest to their matched bronchiectasis patient's index date. All patients had continuous enrollment for at least 12 months pre-index (baseline) and at least 12 months post-index. Primary outcomes were all-cause, respiratory-related, and bronchiectasis-related HCRU and health care costs, which were presented by the overall sample and by segmented patient cohorts based on the number of exacerbations during baseline (0, 1, or ≥2).

RESULTS

92,529 patients with bronchiectasis (mean [SD] age, 76.7 [8.8] years; 72.3% female) and 92,529 matched controls qualified for the study. Compared with controls, patients with bronchiectasis presented greater mean (SD) all-cause physician visits (15.4 [10.0] vs 13.2 [9.7]; P < 0.001) and respiratory-related physician visits (5.2 [4.3] vs 1.9 [3.1]), pulmonologist visits (1.9 [2.2] vs 0.3 [1.0]), hospitalizations (0.4 [0.9] vs 0.3 [0.8]), emergency department visits (0.33 [1.0] vs 0.26 [1.0]), and total health care costs ($10,224 [$23,263] vs $6,704 [$19,593]). Respiratory-related HCRU was also greater in patients with more baseline exacerbations, with total health care costs of $8,506, $10,365, and $14,790 for patients with 0, 1, and at least 2 exacerbations, respectively (P < 0.01).

CONCLUSIONS

This real-world study demonstrates the high disease burden associated with bronchiectasis and with exacerbations, highlighting the need to improve management and reduce exacerbations.

Eosinophilic Bronchiectasis: Prevalence, Severity, and Associated Features-A Cohort Study

Background: Bronchiectasis (BE) has been traditionally associated with neutrophilic inflammation, but eosinophilic bronchiectasis (EB) has recently emerged. Data about prevalence, clinical features, and disease severity are lacking. This study aimed to assess the EB prevalence, compare EB with non-EB, evaluate the Type-2 (T2) high endotype in BE (T2-high EB) versus non-T2-high EB, and identify EB predictors. Methods: We conducted a prospective study involving 153 BE patients. The data collected included clinical, radiological, and microbiological findings. BE severity was assessed using the bronchiectasis severity index (BSI), FACED and E-FACED scores, and the bronchiectasis etiology and comorbidity index (BACI). EB was defined as a blood eosinophil count (BEC) ≥ 300 cells/μL, and T2-high EB as BEC ≥ 300 cells/μL with fractional exhaled nitric oxide (FeNO) ≥ 25 ppb. Results: Prevalence was 27% for EB and 20% for T2-high EB. EB patients exhibited poorer lung function and more severe radiologic features, with significantly higher severity scores [BSI, FACED, E-FACED, BACI (p < 0.05)], and a higher median exacerbation rate [4 (2-5) in EB vs. 2 (1-4) in non-EB, p = 0.0002], compared with non-EB patients. T2-high EB patients showed higher severity scores [BSI, FACED, E-FACED (p < 0.05)], as well as worse lung function parameters [FEV1%, FVC%, FEF 25-75% (p < 0.05)] compared with non-T2-high EB patients. In our study, patients with EB exhibited notably worsened lung function and higher BE severity scores compared with their non-EB counterparts, with exacerbations playing a major role in these differences. We found statistically significant positive correlations between BEC and disease severity scores, such as BSI, FACED, and mMRC, as well as an inverse relationship with pulmonary function. The likelihood of EB being present was significantly higher in association with mMRC ≥ 1 (OR = 2.53; 95% CI, 1.26-5.64), exacerbations/year ≥ 1 (OR = 1.27; 95% CI, 1.0-1.63), and chronic PA colonization (OR = 3.9; 95% CI, 1.08-15.8). Conclusions: EB is a distinct endotype. Dyspnea, exacerbations, and PA colonization may be predictive of EB, emphasizing the importance of early detection for improved outcomes. BEC could serve as a useful biomarker of disease severity to consider when diagnosing EB.

Increasing serum miR-223-3p indicates the onset, severe development, and adverse prognosis of bronchiectasis: a retrospective study

BACKGROUND

miR-223-3p has been demonstrated as a Pseudomonas aeruginosa colonization-related miRNA in bronchiectasis (BE), but its clinical value in BE has not been revealed, which is of great significance for the clinical diagnosis and monitoring of BE. This study aimed to identify a reliable biomarker for screening BE and predicting patients' outcomes.

METHODS

The serum expression of miR-223-3p was compared between healthy individuals (n = 101) and BE patients (n = 133) and evaluated its potential in distinguishing BE patients. The severity of BE patients was estimated by BSI and FACED score, and the correlation of miR-223-3p with inflammation and severity of BE patients was evaluated by Pearson correlation analysis. BE patients were followed up for 3 years, and the predictive value of miR-223-3p in prognosis was assessed by logistic regression analysis.

RESULTS

Significant upregulation of miR-223-3p was observed in BE patients, which significantly distinguished BE patients and showed positive correlations with C-reactive protein (CRP), procalcitonin (PCT), interleukin 6 (IL-6), and neutrophil-to-lymphocyte ratio (NLR) of BE patients. Additionally, miR-223-3p was also positively correlated with BSI and FACED scores, indicating its correlation with inflammation and severity of BE. BE patients with adverse prognoses showed a higher serum miR-223-3p level, which was identified as an adverse prognostic factor and discriminated patients with different prognoses.

CONCLUSION

Increasing serum miR-223-3p can be considered a biomarker for the onset, severity, and prognosis of BE.

Phenotypical characteristics of nontuberculous mycobacterial infection in patients with bronchiectasis

BACKGROUND

The global mortality and morbidity rates of bronchiectasis patients due to nontuberculous mycobacteria (NTM) pulmonary infection are on a concerning upward trend. The aims of this study to identify the phenotype of NTM-positive individuals with bronchiectasis.

METHODS

A retrospective single-center observational study was conducted in adult patients with bronchiectasis who underwent bronchoscopy in 2007-2020. Clinical, laboratory, pulmonary function, and radiological data were compared between patients with a positive or negative NTM culture.

RESULTS

Compared to the NTM-negative group (n=677), the NTM-positive group (n=94) was characterized (P ≤0.05 for all) by older age, greater proportion of females, and higher rates of gastroesophageal reflux disease and muco-active medication use; lower body mass index, serum albumin level, and lymphocyte and eosinophil counts; lower values of forced expiratory volume in one second, forced vital capacity, and their ratio, and lower diffusing lung capacity for carbon monoxide; higher rates of bronchiectasis in both lungs and upper lobes and higher number of involved lobes; and more exacerbations in the year prior bronchoscopy. On multivariate analysis, older age (OR 1.05, 95% CI 1.02-1.07, P=0.001), lower body mass index (OR 1.16, 95% CI 1.16-1.07, P <0.001), and increased number of involved lobes (OR 1.26, 95% CI 1.01-1.44, P=0.04) were associated with NTM infection.

CONCLUSIONS

Patients with bronchiectasis and NTM pulmonary infection are more likely to be older and female with more severe clinical, laboratory, pulmonary function, and radiological parameters than those without NTM infection. This phenotype can be used for screening patients with suspected NTM disease.

An experimentally validated approach to automated biological evidence generation in drug discovery using knowledge graphs

Explaining predictions for drug repositioning with biological knowledge graphs is a challenging problem. Graph completion methods using symbolic reasoning predict drug treatments and associated rules to generate evidence representing the therapeutic basis of the drug. Yet the vast amounts of generated paths that are biologically irrelevant or not mechanistically meaningful within the context of disease biology can limit utility. We use a reinforcement learning based knowledge graph completion model combined with an automatic filtering approach that produces the most relevant rules and biological paths explaining the predicted drug's therapeutic connection to the disease. In this work we validate the approach against preclinical experimental data for Fragile X syndrome demonstrating strong correlation between automatically extracted paths and experimentally derived transcriptional changes of selected genes and pathways of drug predictions Sulindac and Ibudilast. Additionally, we show it reduces the number of generated paths in two case studies, 85% for Cystic fibrosis and 95% for Parkinson's disease.

Kartagener's syndrome: A rare condition diagnosed in a young male patient

Kartagener's Syndrome is a rare autosomal recessive genetic condition, that affects the structure and function of cilia and includes a condition of situs inversus, chronic sinusitis, and bronchiectasis associated sometimes with infertility. A young patient who had a long-time fever, cough, and infertility after a clinical evaluation performed a chest X-ray and a CT scan that revealed the unexpected condition of Situs Inversus Totalis (SIT). Imaging also showed bronchiectasis and sinusitis: all findings consistent with Kartagener's syndrome, confirmed a second time by the genetic test. This case highlights the importance of knowing and considering situs inversus in clinical practice, particularly when interpreting imaging studies and planning medical interventions. Furthermore, as situs inversus may be associated with cardiovascular and pulmonary pathologies in several syndromic conditions, such as Kartagener's syndrome in this case, these conditions should always be carefully examined.

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.

Neutrophil serine proteases in cystic fibrosis: role in disease pathogenesis and rationale as a therapeutic target

Chronic airway inflammation is a central feature in the pathogenesis of bronchiectasis (BE), which can be caused by cystic fibrosis (CFBE; hereafter referred to as CF lung disease) and non-CF-related conditions (NCFBE). Inflammation in both CF lung disease and NCFBE is predominantly driven by neutrophils, which release proinflammatory cytokines and granule proteins, including neutrophil serine proteases (NSPs). NSPs include neutrophil elastase, proteinase 3 and cathepsin G. An imbalance between NSPs and their antiproteases has been observed in people with CF lung disease and people with NCFBE. While the role of the protease/antiprotease imbalance is well established in both CF lung disease and NCFBE, effective therapies targeting NSPs are lacking. In recent years, the introduction of CF transmembrane conductance regulator (CFTR) modulator therapy has immensely improved outcomes in many people with CF (pwCF). Despite this, evidence suggests that airway inflammation persists, even in pwCF treated with CFTR modulator therapy. In this review, we summarise current data on neutrophilic inflammation in CF lung disease to assess whether neutrophilic inflammation and high, uncontrolled NSP levels play similar roles in CF lung disease and in NCFBE. We discuss similarities between the neutrophilic inflammatory profiles of people with CF lung disease and NCFBE, potentially supporting a similar therapeutic approach. Additionally, we present evidence suggesting that neutrophilic inflammation persists in pwCF treated with CFTR modulator therapy, at levels similar to those in people with NCFBE. Collectively, these findings highlight the ongoing need for new treatment strategies targeting neutrophilic inflammation in CF lung disease.

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.

Increased bronchiectasis risk and related risk factors in inflammatory bowel disease: a 10-year Korean national cohort study

Background

The association between inflammatory bowel disease (IBD) and an increased risk of bronchiectasis, as well as contributing factors, remains unclear. Additionally, whether bronchiectasis increases disease burden in IBD remains unknown. Therefore, this study aimed to: 1) assess whether IBD increases the risk of incident bronchiectasis; 2) compare the risk of bronchiectasis between individuals with Crohn's disease (CD) and those with ulcerative colitis (UC); 3) identify risk factors for bronchiectasis in individuals with IBD; and 4) examine the disease burden in individuals with IBD and bronchiectasis versus those without.

Methods

We conducted a population-based matched cohort study involving adults aged ≥20 years with IBD, using data acquired from the Korean National Health Insurance Service-National Sample Cohort database between 2002 and 2012.

Results

During the mean follow-up of 9.6 years, the incidence rate of bronchiectasis was 419.63 out of 100 000 person-years (PY) and 309.65 out of 100 000 PY in the IBD and matched cohorts (adjusted hazard ratio (aHR) 1.21, 95% CI 1.05-1.39), respectively. UC was associated with increased bronchiectasis risk (aHR 1.42, 95% CI 1.19-1.69), but CD was not. Multivariate Cox regression analyses showed that age, male sex, medical aid, underweight status, COPD and diabetes mellitus were associated with an increased risk of bronchiectasis in the IBD cohort (p<0.05). The mortality, emergency department visit and hospitalisation rates were significantly higher for individuals with IBD and bronchiectasis compared with those without bronchiectasis (p<0.05).

Conclusion

IBD is associated with increased risk of bronchiectasis, which results in a greater disease burden in individuals with IBD.

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.

Five-Year Outcomes among U.S. Bronchiectasis and NTM Research Registry Patients

Rationale: Nontuberculous mycobacteria (NTM) are prevalent among patients with bronchiectasis. However, the long-term natural history of patients with NTM and bronchiectasis is not well described. Objectives: To assess the impact of NTM on 5-year clinical outcomes and mortality in patients with bronchiectasis. Methods: Patients in the Bronchiectasis and NTM Research Registry with ⩾5 years of follow-up were eligible. Data were collected for all-cause mortality, lung function, exacerbations, hospitalizations, and disease severity. Outcomes were compared between patients with and without NTM at baseline. Mortality was assessed using Cox proportional hazards models and the log-rank test. Measurements and Main Results: In total, 2,634 patients were included: 1,549 (58.8%) with and 1,085 (41.2%) without NTM at baseline. All-cause mortality (95% confidence interval) at Year 5 was 12.1% (10.5%, 13.7%) overall, 12.6% (10.5%, 14.8%) in patients with NTM, and 11.5% (9.0%, 13.9%) in patients without NTM. Independent predictors of 5-year mortality were baseline FEV1 percent predicted, age, hospitalization within 2 years before baseline, body mass index, and sex (all P < 0.01). The probabilities of acquiring NTM or Pseudomonas aeruginosa were approximately 4% and 3% per year, respectively. Spirometry, exacerbations, and hospitalizations were similar, regardless of NTM status, except that annual exacerbations were lower in patients with NTM (P < 0.05). Conclusions: Outcomes, including exacerbations, hospitalizations, rate of loss of lung function, and mortality rate, were similar across 5 years in patients with bronchiectasis with or without NTM.

Medical Causes of Hospitalisation among Patients with Bronchiectasis: A Nationwide Study in Japan

PURPOSE

Although the international guidelines for managing bronchiectasis are centred on preventing the exacerbation of bronchiectasis, the medical causes of admissions to hospital among patients with bronchiectasis have not been fully investigated.

METHODS

This study targeted patients with bronchiectasis who were admitted to hospitals between April 2018 and March 2020 using the national inpatient database in Japan. The causes of hospitalisation and types of antibiotics used for hospitalised patients were recorded.

RESULTS

In total, 21,300 hospitalisations of 16,723 patients with bronchiectasis were analysed. The most common cause was respiratory diseases in 15,145 (71.1%) admissions, including bacterial pneumonia and the exacerbation of bronchiectasis in 6238 (41.2%) and 3151 (20.8%), respectively. Antipseudomonal antibiotics were used in approximately 60% of patients with bacterial pneumonia who were administered antibiotic treatments and in approximately 50% of patients with the exacerbation of bronchiectasis.

CONCLUSIONS

Bacterial pneumonia was the most frequent cause of hospitalisation, followed by the exacerbation of bronchiectasis, among patients with bronchiectasis. Physicians need to focus on the prevention of bacterial pneumonia in addition to the exacerbation of bronchiectasis in patients with bronchiectasis.

The role of radiological imaging in the management of severe and difficult-to-treat asthma

Radiological imaging has proven to be a useful tool in the assessment of asthma, its comorbidities and potential complications. Characteristic chest radiograph and computed tomography scan findings can be seen in asthma and in other conditions that can coexist with or be misdiagnosed as asthma, including chronic rhinosinusitis, inducible laryngeal obstruction, excessive dynamic airway collapse, tracheobronchomalacia, concomitant COPD, bronchiectasis, allergic bronchopulmonary aspergillosis, eosinophilic granulomatosis with polyangiitis, and eosinophilic pneumonia. The identification of the characteristic radiological findings of these conditions is often essential in making the correct diagnosis and provision of appropriate management and treatment. Furthermore, radiological imaging modalities can be used to monitor response to therapy.

Effects of high-flow nasal cannula oxygen therapy in bronchiectasis and hypercapnia: a retrospective observational study

BACKGROUND

The effectiveness of high-flow nasal cannula (HFNC) therapy in patients with bronchiectasis experiencing hypercapnia remains unclear. Our aim was to retrospectively analyze the short-term outcomes of HFNC therapy in such patients, and to further explore the predictors of HFNC treatment failure in this particular patient population.

METHODS

A retrospective review was conducted on patients with bronchiectasis who received HFNC (n = 70) for hypercapnia (arterial partial pressure of carbon dioxide, PaCO2 ≥ 45 mmHg) between September 2019 and September 2023.

RESULTS

In the study population, 30% of patients presented with acidemia (arterial pH < 7.35) at baseline. Within 24 h of HFNC treatment, there was a significant reduction in PaCO2 levels by a mean of 4.0 ± 12.7 mmHg (95% CI -7.0 to -1.0 mmHg). Concurrently, arterial pH showed a statistically significant increase with a mean change of 0.03 ± 0.06 (95% CI 0.01 to 0.04). The overall hospital mortality rate in our study was 17.5%. The median length of hospital stay was 11.0 days (interquartile range [IQR] 8.0 to 16.0 days). Sub-analysis revealed no statistically significant differences in hospital mortality (19.0% vs. 20.4%, p = 0.896), length of hospital stay (median 14.0 days [IQR 9.0 to 18.0 days] vs. 10.0 days [IQR 7.0 to 16.0 days], p = 0.117) and duration of HFNC application (median 5.0 days [IQR 2.0 to 8.5 days] vs. 6.0 days [IQR 4.9 to 9.5 days], p = 0.076) between the acidemia group and the non-acidemia group (arterial pH ≥ 7.35). However, more patients in the non-acidemia group had do-not-intubate orders. The overall treatment failure rate for HFNC was 28.6%. Logistic regression analysis identified the APACHE II score (OR 1.24 per point) as the independent predictor of HFNC failure.

CONCLUSIONS

In patients with bronchiectasis and hypercapnia, HFNC as an initial respiratory support can effectively reduce PaCO2 level within 24 h of treatment. A high APACHE II score has emerged as a prognostic indicator for HFNC treatment failure. These observations highlight randomized controlled trials to meticulously evaluate the efficacy of HFNC in this specific population.

The impact of smoking on bronchiectasis and its comorbidities

INTRODUCTION

Bronchiectasis, characterized by irreversible bronchial dilatation, is a growing global health concern with significant morbidity. This review delves into the intricate relationship between smoking and bronchiectasis, examining its epidemiology, pathophysiology, clinical manifestations, and therapeutic approaches. Our comprehensive literature search on PubMed utilized MESH terms including 'smoking,' 'smoking cessation,' 'bronchiectasis,' and 'comorbidities' to gather relevant studies.

AREAS COVERED

This review emphasizes the role of smoking in bronchiectasis development and exacerbation by compromising airways and immune function. Interconnected comorbidities, including chronic obstructive pulmonary disease, asthma, and gastroesophageal reflux disease, create a detrimental cycle affecting patient outcomes. Despite limited studies on smoking cessation in bronchiectasis, the review stresses its importance. Advocating for tailored cessation programs, interventions like drainage, bronchodilators, and targeted antibiotics are crucial to disrupting the inflammatory-infection-widening cycle.

EXPERT OPINION

The importance of smoking cessation in bronchiectasis management is paramount due to its extensive negative impact on related conditions. Proactive cessation programs utilizing technology and targeted education for high-risk groups aim to reduce smoking's impact on disease progression and related comorbidities. In conclusion, a personalized approach centered on smoking cessation is deemed vital for bronchiectasis, aiming to improve outcomes and enhance patients' quality of life in the face of this complex respiratory condition.

Clinical significance and potential pathogenesis of VCAN in adult non-cystic fibrosis bronchiectasis: a retrospective study

BACKGROUND

The pathogenesis of adult non-cystic fibrosis (CF) bronchiectasis is complex, and the relevant molecular mechanism remains ambiguous. Versican (VCAN) is a key factor in inflammation through interactions with adhesion molecules. This study constructs a stable panoramic map of mRNA, reveals the possible pathogenesis of bronchiectasis, and provides new ideas and methods for bronchiectasis.

METHODS

Peripheral blood and tissue gene expression data from patients with bronchiectasis and normal control were selected by bioinformatics analysis. The expression of VCAN in peripheral blood and bronchial tissues of bronchiectasis were obtained by transcriptome sequencing. The protein expression levels of VCAN in serums were verified by the enzyme-linked immunosorbent assay (ELISA). The mRNA expression levels of VCAN in co-culture of Pseudomonas aeruginosa and bronchial epithelial cells were verified by real-time quantitative polymerase chain reaction (RT-qPCR). In addition, the biological function of VCAN was detected by the transwell assay.

RESULTS

The expression of VCAN was upregulated in the bronchiectasis group by sequencing analysis (P < 0.001). The expression of VCAN in the bronchial epithelial cell line BEAS-2B was increased in P. aeruginosa (P.a), which was co-cultured with BEAS-2B cells (P < 0.05). The concentration of VCAN protein in the serum of patients with bronchiectasis was higher than that in the normal control group (P < 0.05). Transwell experiments showed that exogenous VCAN protein induced the migration of neutrophils (P < 0.0001).

CONCLUSIONS

Our findings indicate that VCAN may be involved in the development of bronchiectasis by increasing the migration of neutrophils and play an important role in bronchial pathogenesis.

The Lung Microbiome

Although the lungs were once considered a sterile environment, advances in sequencing technology have revealed dynamic, low-biomass communities in the respiratory tract, even in health. Key features of these communities-composition, diversity, and burden-are consistently altered in lung disease, associate with host physiology and immunity, and can predict clinical outcomes. Although initial studies of the lung microbiome were descriptive, recent studies have leveraged advances in technology to identify metabolically active microbes and potential associations with their immunomodulatory by-products and lung disease. In this brief review, we discuss novel insights in airway disease and parenchymal lung disease, exploring host-microbiome interactions in disease pathogenesis. We also discuss complex interactions between gut and oropharyngeal microbiota and lung immunobiology. Our advancing knowledge of the lung microbiome will provide disease targets in acute and chronic lung disease and may facilitate the development of new therapeutic strategies.

Biofilm exopolysaccharides alter sensory-neuron-mediated sickness during lung infection

Infections of the lung cause observable sickness thought to be secondary to inflammation. Signs of sickness are crucial to alert others via behavioral-immune responses to limit contact with contagious individuals. Gram-negative bacteria produce exopolysaccharide (EPS) that provides microbial protection; however, the impact of EPS on sickness remains uncertain. Using genome-engineered Pseudomonas aeruginosa (P. aeruginosa) strains, we compared EPS-producers versus non-producers and a virulent Escherichia coli (E. coli) lung infection model in male and female mice. EPS-negative P. aeruginosa and virulent E. coli infection caused severe sickness, behavioral alterations, inflammation, and hypothermia mediated by TLR4 detection of the exposed lipopolysaccharide (LPS) in lung TRPV1+ sensory neurons. However, inflammation did not account for sickness. Stimulation of lung nociceptors induced acute stress responses in the paraventricular hypothalamic nuclei by activating corticotropin-releasing hormone neurons responsible for sickness behavior and hypothermia. Thus, EPS-producing biofilm pathogens evade initiating a lung-brain sensory neuronal response that results in sickness.

Autoimmune diseases and their genetic link to bronchiectasis: insights from a genetic correlation and Mendelian randomization study

Background

Previous studies have demonstrated that autoimmune diseases are closely associated with bronchiectasis (BE). However, the causal effects between autoimmune diseases and BE remain elusive.

Methods

All summary-level data were obtained from large-scale Genome-Wide Association Studies (GWAS). The univariate Mendelian randomization (UVMR) was utilized to investigate the genetic causal correlation (rg) of 12 autoimmune diseases and bronchiectasis, The Multivariable Mendelian Randomization (MVMR) method was used to explore the effects of the confounding factors. Further investigation was conducted to identify potential intermediate factors using mediation analysis. Finally, the linkage disequilibrium score regression (LDSC) method was used to identify genetic correlations among complex traits. A series of sensitivity analyses was performed to validate the robustness of the results.

Results

The LDSC analysis revealed significant genetic correlations between BE and Crohn's disease (CD) (rg = 0.220, P = 0.037), rheumatoid arthritis (RA) (rg = 0.210, P = 0.021), and ulcerative colitis (UC) (rg = 0.247, P = 0.023). However, no genetic correlation was found with other autoimmune diseases (P > 0.05). The results of the primary IVW analysis suggested that for every SD increase in RA, there was a 10.3% increase in the incidence of BE (odds ratio [OR] = 1.103, 95% confidence interval [CI] 1.055-1.154, P = 1.75×10-5, FDR = 5.25×10-5). Furthermore, for every standard deviation (SD) increase in celiac disease (CeD), the incidence of BE reduced by 5.1% (OR = 0.949, 95% CI 0.902-0.999, P = 0.044, FDR = 0.044). We also observed suggestive evidence corresponding to a 3% increase in BE incidence with T1DM (OR = 1.033, 95% CI 1.001-1.066, P = 0.042, FDR = 0.063). Furthermore, MVMR analysis showed that RA was an independent risk factor for BE, whereas mediator MR analysis did not identify any mediating factors. The sensitivity analyses corroborated the robustness of these findings.

Conclusion

LDSC analysis revealed significant genetic correlations between several autoimmune diseases and BE, and further MVMR analysis showed that RA is an independent risk factor for BE.