Airway inflammation in children with cystic fibrosis and healthy children assessed by sputum induction

Extracellular vesicles in sputum of children with cystic fibrosis pulmonary exacerbations

Background

The aim of this study was to quantify mediators of neutrophilic inflammation within airway extracellular vesicles (EVs) of children treated for a cystic fibrosis (CF) pulmonary exacerbation (PEx).

Methods

EVs were isolated from stored sputum samples collected before and after antibiotic therapy for PEx between 2011 and 2013, and characterised by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM). Western blot analysis of EV protein extracts was used for EV canonical protein markers CD63, CD9 and flotillin-1 (FLOT1), as well as neutrophil elastase (NE), myeloperoxidase (MPO) and interleukin-8. The EV content of NE and MPO were expressed as ratios of NE/FLOT1 and MPO/FLOT1 protein band densities.

Results

Sputum samples from 21 children aged 13.3 (range 8.0-17.0) years were analysed. NTA showed high concentrations of particles at the size of small EVs (50-200 nm), and typical EV morphology was confirmed by TEM. CD63, CD9 and FLOT1 were detectable in all samples. Median (interquartile range (IQR)) NE/FLOT1 increased from 2.46 (1.68-5.25) before to 6.83 (3.89-8.89, p<0.001) after PEx therapy, and median (IQR) MPO/FLOT1 increased from 2.30 (1.38-4.44) before to 5.76 (3.45-6.94, p<0.01) after, while EV size remained unchanged. Improvement in lung function (percent predicted forced expiratory volume in 1 s (ppFEV1)) with PEx therapy correlated with NE EV content (r=0.657, p=0.001).

Conclusions

Airways of children with CF contain EVs that carry NE and MPO as cargo. The lower NE and MPO content at the time of PEx, compared with after therapy, and the correlation with pulmonary function suggest both a functional role of EVs in CF airway inflammation and the potential of EVs as a biomarker to monitor CF lung disease.

Cytokines Measured in Nasal Lavage Compared to Induced Sputum in Patients with Mild Cystic Fibrosis

The measurement of cytokines in induced sputum and nasal lavage (NL) samples has been performed for years in people with cystic fibrosis (CF). The aim of this study was to directly compare sputum and NL samples and interpret results based on disease severity in patients who were categorized as having mild or severe lung disease. The categorization was based primarily on structural abnormalities detected on lung computed tomography and secondarily on lung function. The serum inflammatory markers neutrophil elastase (NE), IL-1β, 2, 6, 8, 10 and 17a were measured in each sputum and NL sample. Thirty-two sample pairs from 29 patients were included in this study (13 mild, 19 severe). In the patients classified as severe, many systemic inflammatory markers as well as sputum cytokines were significantly higher compared to those in the mild patients. However, all the markers measured in the NL were higher in the mild patients (p =< 0.05 for NE, IL-6 and IL-8). In addition, many cytokines in the NL correlated negatively with those in the sputum samples. Major differences in the cytokine levels were shown although the samples were obtained at the same time in the same patient. Advanced structural lung disease was closely related to systemic and lower airway inflammation, whereas preserved lung function was associated with higher levels in the NL. We hypothesize that the main part of the immune response takes place in the nasal mucosa in patients with minor pulmonary changes. Our results suggest that inflammation must be interpreted individually depending on the compartment in which it is measured. Further research is needed to accurately understand inflammatory markers measured in NL.

Association of clinical and imaging characteristics with pulmonary function testing in patients with Long-COVID

Purpose

The purpose of this study is to identify clinical and imaging characteristics associated with post-COVID pulmonary function decline.

Methods

This study included 22 patients recovering from COVID-19 who underwent serial spirometry pulmonary function testing (PFT) before and after diagnosis. Patients were divided into two cohorts by difference between baseline and post-COVID follow-up PFT: Decline group (>10 % decrease in FEV1), and Stable group (≤10 % decrease or improvement in FEV1). Demographic, clinical, and laboratory data were collected, as well as PFT and chest computed tomography (CT) at the time of COVID diagnosis and follow-up. CTs were semi-quantitatively scored on a five-point severity scale for disease extent in each lobe by two radiologists. Mann-Whitney U-tests, T-tests, and Chi-Squared tests were used for comparison. P-values <0.05 were considered statistically significant.

Results

The Decline group had a higher proportion of neutrophils (79.47 ± 4.83 % vs. 65.45 ± 10.22 %; p = 0.003), a higher absolute neutrophil count (5.73 ± 2.68 × 109/L vs. 3.43 ± 1.74 × 109/L; p = 0.031), and a lower proportion of lymphocytes (9.90 ± 4.20 % vs. 21.21 ± 10.97 %; p = 0.018) compared to the Stable group. The Decline group also had significantly higher involvement of ground-glass opacities (GGO) on follow-up chest CT [8.50 (4.50, 14.50) vs. 3.0 (1.50, 9.50); p = 0.032] and significantly higher extent of reticulations on chest CT at time of COVID diagnosis [6.50 (4.00, 9.00) vs. 2.00 (0.00, 6.00); p = 0.039] and follow-up [5.00 (3.00, 13.00) vs. 2.00 (0.00, 5.00); p = 0.041]. ICU admission was higher in the Decline group than in the Stable group (71.4 % vs. 13.3 %; p = 0.014).

Conclusions

This study provides novel insight into factors influencing post-COVID lung function, irrespective of pre-existing pulmonary conditions. Our findings underscore the significance of neutrophil counts, reduced lymphocyte counts, pulmonary reticulation on chest CT at diagnosis, and extent of GGOs on follow-up chest CT as potential indicators of decreased post-COVID lung function. This knowledge may guide prediction and further understanding of long-term sequelae of COVID-19 infection.

[CF Lung Disease - a German S3 Guideline: Pseudomonas aeruginosa]

Cystic Fibrosis (CF) is the most common autosomal recessive genetic multisystemic disease. In Germany, it affects at least 8000 people. The disease is caused by mutations in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene leading to dysfunction of CFTR, a transmembrane chloride channel. This defect causes insufficient hydration of the airway epithelial lining fluid which leads to reduction of the mucociliary clearance.Even if highly effective, CFTR modulator therapy has been available for some years and people with CF are getting much older than before, recurrent and chronic infections of the airways as well as pulmonary exacerbations still occur. In adult CF life, Pseudomonas aeruginosa (PA) is the most relevant pathogen in colonisation and chronic infection of the lung, leading to further loss of lung function. There are many possibilities to treat PA-infection.This is a S3-clinical guideline which implements a definition for chronic PA-infection and demonstrates evidence-based diagnostic methods and medical treatment in order to give guidance for individual treatment options.

A randomised trial of oral prednisone for cystic fibrosis pulmonary exacerbation treatment

BACKGROUND

Elevated markers of systemic and pulmonary inflammation are associated with failure to recover lung function following pulmonary exacerbations in people with cystic fibrosis (pwCF). Our aim was to determine whether adjuvant oral prednisone treatment would improve recovery of forced expiratory volume in 1 s (FEV1) % pred in CF pulmonary exacerbations not responding to antibiotic therapy.

METHODS

This was a randomised, double-blind, placebo-controlled trial in pwCF treated with intravenous antibiotics for a pulmonary exacerbation. At day 7, those who had not returned to >90% baseline FEV1 % pred were randomised to adjuvant prednisone 1 mg·kg-1 twice daily (maximum 60 mg·day-1) or placebo for 7 days. The primary outcome was the difference in proportion of subjects who recovered >90% baseline FEV1 % pred at day 14 of i.v. antibiotic therapy.

RESULTS

173 subjects were enrolled, with 76 randomised. 50% of subjects in the prednisone group recovered baseline FEV1 on day 14 compared with 39% of subjects in the placebo group (difference of 11%, 95% CI -11-34%; p=0.34). The mean±sd change in FEV1 % pred from day 7 to day 14 was 6.8±8.8% predicted in the prednisone group and 4.6±6.9% predicted in the placebo group (mean difference 2.2% predicted, 95% CI -1.5-5.9%; p=0.24). Time to subsequent exacerbation was not prolonged in prednisone-treated subjects (hazard ratio 0.83, 95% CI 0.45-1.53; p=0.54).

CONCLUSIONS

This study failed to detect a difference in FEV1 % pred recovery between adjuvant oral prednisone and placebo treatment in pwCF not responding at day 7 of i.v. antibiotic therapy for pulmonary exacerbations.

P. aeruginosa tRNA-fMet halves secreted in outer membrane vesicles suppress lung inflammation in cystic fibrosis

Although tobramycin increases lung function in people with cystic fibrosis (pwCF), the density of Pseudomonas aeruginosa (P. aeruginosa) in the lungs is only modestly reduced by tobramycin; hence, the mechanism whereby tobramycin improves lung function is not completely understood. Here, we demonstrate that tobramycin increases 5' tRNA-fMet halves in outer membrane vesicles (OMVs) secreted by laboratory and CF clinical isolates of P. aeruginosa. The 5' tRNA-fMet halves are transferred from OMVs into primary CF human bronchial epithelial cells (CF-HBEC), decreasing OMV-induced IL-8 and IP-10 secretion. In mouse lungs, increased expression of the 5' tRNA-fMet halves in OMVs attenuated KC (murine homolog of IL-8) secretion and neutrophil recruitment. Furthermore, there was less IL-8 and neutrophils in bronchoalveolar lavage fluid isolated from pwCF during the period of exposure to tobramycin versus the period off tobramycin. In conclusion, we have shown in mice and in vitro studies on CF-HBEC that tobramycin reduces inflammation by increasing 5' tRNA-fMet halves in OMVs that are delivered to CF-HBEC and reduce IL-8 and neutrophilic airway inflammation. This effect is predicted to improve lung function in pwCF receiving tobramycin for P. aeruginosa infection.NEW & NOTEWORTHY The experiments in this report identify a novel mechanism, whereby tobramycin reduces inflammation in two models of CF. Tobramycin increased the secretion of tRNA-fMet halves in OMVs secreted by P. aeruginosa, which reduced the OMV-LPS-induced inflammatory response in primary cultures of CF-HBEC and in mouse lung, an effect predicted to reduce lung damage in pwCF.

How Does Airway Surface Liquid Composition Vary in Different Pulmonary Diseases, and How Can We Use This Knowledge to Model Microbial Infections?

Growth environment greatly alters many facets of pathogen physiology, including pathogenesis and antimicrobial tolerance. The importance of host-mimicking environments for attaining an accurate picture of pathogen behaviour is widely recognised. Whilst this recognition has translated into the extensive development of artificial cystic fibrosis (CF) sputum medium, attempts to mimic the growth environment in other respiratory disease states have been completely neglected. The composition of the airway surface liquid (ASL) in different pulmonary diseases is far less well characterised than CF sputum, making it very difficult for researchers to model these infection environments. In this review, we discuss the components of human ASL, how different lung pathologies affect ASL composition, and how different pathogens interact with these components. This will provide researchers interested in mimicking different respiratory environments with the information necessary to design a host-mimicking medium, allowing for better understanding of how to treat pathogens causing infection in these environments.

SPLUNC1 as a biomarker of pulmonary exacerbations in children with cystic fibrosis

BACKGROUND

Short palate, lung, and nasal epithelium clone 1 (SPLUNC1) is an innate defence protein that acts as an anti-microbial agent and regulates airway surface liquid volume through inhibition of the epithelial sodium channel (ENaC). SPLUNC1 levels were found to be reduced in airway secretions of adults with cystic fibrosis (CF). The potential of SPLUNC1 as a biomarker in children with CF is unknown.

METHODS

We quantified SPLUNC1, interleukin-8 (IL-8) and neutrophil elastase (NE) in sputum of CF children treated with either intravenous antibiotics or oral antibiotics for a pulmonary exacerbation (PEx)s, and in participants of a prospective cohort of CF children with preserved lung function on spirometry, followed over a period of two years.

RESULTS

Sputum SPLUNC1 levels were significantly lower before compared to after intravenous and oral antibiotic therapy for PEx. In the longitudinal cohort, SPLUNC1 levels were found to be decreased at PEx visits compared to both previous and subsequent stable visits. Higher SPLUNC1 levels at stable visits were associated with longer PEx-free time (hazard ratio 0.85, p = 0.04). SPLUNC1 at PEx visits did not correlate with IL-8 or NE levels in sputum or forced expiratory volume in one second (FEV1) but did correlate with the lung clearance index (LCI) (r=-0.53, p < 0.001).

CONCLUSION

SPLUNC1 demonstrates promising clinometric properties as a biomarker of PEx in children with CF.

P. aeruginosa tRNA-fMet halves secreted in outer membrane vesicles suppress lung inflammation in Cystic Fibrosis

Although tobramycin increases lung function in people with cystic fibrosis (pwCF), the density of Pseudomonas aeruginosa (P. aeruginosa) in the lungs is only modestly reduced by tobramycin; hence, the mechanism whereby tobramycin improves lung function is not completely understood. Here, we demonstrate that tobramycin increases 5' tRNA-fMet halves in outer membrane vesicles (OMVs) secreted by laboratory and CF clinical isolates of P. aeruginosa . The 5' tRNA-fMet halves are transferred from OMVs into primary CF human bronchial epithelial cells (CF-HBEC), decreasing OMV-induced IL-8 and IP-10 secretion. In mouse lung, increased expression of the 5' tRNA-fMet halves in OMVs attenuated KC secretion and neutrophil recruitment. Furthermore, there was less IL-8 and neutrophils in bronchoalveolar lavage fluid isolated from pwCF during the period of exposure to tobramycin versus the period off tobramycin. In conclusion, we have shown in mice and in vitro studies on CF-HBEC that tobramycin reduces inflammation by increasing 5' tRNA-fMet halves in OMVs that are delivered to CF-HBEC and reduce IL-8 and neutrophilic airway inflammation. This effect is predicted to improve lung function in pwCF receiving tobramycin for P. aeruginosa infection.

New and noteworthy

The experiments in this report identify a novel mechanim whereby tobramycin reduces inflammation in two models of CF. Tobramycin increased the secretion of tRNA-fMet haves in OMVs secreted by P. aeruginiosa , which reduced the OMV-LPS induced inflammatory response in primary cultures of CF-HBEC and in mouse lung, an effect predicted to reduce lung damage in pwCF.

Graphical abstract

The anti-inflammatory effect of tobramycin mediated by 5' tRNA-fMet halves secreted in P. aeruginosa OMVs. (A) P. aeruginosa colonizes the CF lungs and secrets OMVs. OMVs diffuse through the mucus layer overlying bronchial epithelial cells and induce IL-8 secretion, which recruits neutrophils that causes lung damage. ( B ) Tobramycin increases 5' tRNA-fMet halves in OMVs secreted by P. aeruginosa . 5' tRNA-fMet halves are delivered into host cells after OMVs fuse with lipid rafts in CF-HBEC and down-regulate protein expression of MAPK10, IKBKG, and EP300, which suppresses IL-8 secretion and neutrophils in the lungs. A reduction in neutrophils in CF BALF is predicted to improve lung function and decrease lung damage.

Effect of elexacaftor/tezacaftor/ivacaftor on mucus and mucociliary clearance in cystic fibrosis

BACKGROUND

The cystic fibrosis transmembrane conductance regulator (CFTR) modulator elexacaftor/tezacaftor/ivacaftor (E/T/I) is highly effective clinically for those with at least one F508del-CFTR allele. The effects of E/T/I on mucociliary clearance (MCC) and sputum properties are unknown. We, therefore, sought to characterize the effects of E/T/I on in vivo MCC and sputum characteristics hypothesized to impact mucus transport.

METHODS

Forty-four participants ≥12 years of age were enrolled into this prospective, observational trial prior to initiation of E/T/I and had baseline measurement of MCC and characterization of induced sputum and exhaled breath condensate (EBC) samples. Study procedures were repeated after 1 month of E/T/I treatment.

RESULTS

Average age was 27.7 years with baseline forced expiratory volume in 1 second (FEV1) of 78.2 % predicted. 52 % of subjects had previously been treated with a 2-drug CFTR modulator combination. The average whole lung MCC rate measured over 60 min (WLAveClr60) significantly improved from baseline to post-E/T/I (14.8 vs. 22.8 %; p = 0.0002), as did other MCC indices. Sputum% solids also improved (modeled mean 3.4 vs. 2.2 %; p<0.0001), whereas non-significant reductions in sputum macrorheology (G', G") were observed. No meaningful changes in exhaled breath condensate endpoints (sialic acid:urea ratio, pH) were observed.

CONCLUSIONS

E/T/I improved the hydration of respiratory secretions (% solids) and markedly accelerated MCC. These data confirm the link between CFTR function, mucus solid content, and MCC and help to define the utility of MCC and mucus-related bioassays in future efforts to restore CFTR function in all people with CF.

Integrating airway microbiome and blood proteomics data to identify multi-omic networks associated with response to pulmonary infection

Host response to airway infections can vary widely. Cystic fibrosis (CF) pulmonary exacerbations provide an opportunity to better understand the interplay between respiratory microbes and the host. This study aimed to investigate the observed heterogeneity in airway infection recovery by analyzing microbiome and host response (i.e., blood proteome) data collected during the onset of 33 pulmonary infection events. We used sparse multiple canonical correlation network (SmCCNet) analysis to integrate these two types of -omics data along with a clinical measure of recovery. Four microbe-protein SmCCNet subnetworks at infection onset were identified that strongly correlate with recovery. Our findings support existing knowledge regarding CF airway infections. Additionally, we discovered novel microbe-protein subnetworks that are associated with recovery and merit further investigation.

Saline at lower tonicity in cystic fibrosis (SALTI-CF) trial comparing 0.9% versus 3% versus 6% nebulised saline

BACKGROUND

In people with cystic fibrosis (CF), regular nebulisation of 6% or 7% saline improves lung function; however, these concentrations are not always tolerable. Clinically, some CF patients report using lower concentrations of saline to improve tolerability, yet the effects of lower concentrations are unknown. This study therefore aimed to evaluate the relative effectiveness and tolerability of 0.9% versus 3% versus 6% saline nebulised twice daily with an eFlow rapid nebuliser.

METHODS

This was a randomised, blinded, placebo-controlled, parallel-group, multicentre study where subjects inhaled 4 mL of 0.9%, 3% or 6% saline twice daily for 16 weeks. The primary outcome was forced expiratory volume in 1 s. The secondary outcomes were: forced vital capacity (FVC) and forced expiratory flow at 25-75% of FVC; quality of life; exercise capacity; acquisition or loss of bacterial organisms in expectorated sputum; tolerability of nebulised saline; pulmonary exacerbations; and adverse events.

RESULTS

140 participants were randomised to 0.9% (n=47), 3% (n=48) or 6% (n=45) saline. 134 participants (96%) contributed to the intention-to-treat analysis. 3% saline significantly improved lung function and increased the time to first pulmonary exacerbation compared with 0.9% saline but did not improve quality of life. 6% saline had similar benefits to 3% saline but also significantly improved quality of life compared with 3% saline. Only 6% saline delayed the time to intravenous antibiotics for pulmonary exacerbation. Tolerability and adherence were similar.

CONCLUSIONS

Dilution of 6% saline to 3% maintains the benefits for lung function and exacerbation prevention; however, the positive impacts of 6% saline on quality of life and time to i.v. antibiotics for pulmonary exacerbations are lost.

Diagnosis and Management of Cystic Fibrosis Exacerbations

With the improving survival of cystic fibrosis (CF) patients and the advent of highly effective cystic fibrosis transmembrane conductance regulator (CFTR) therapy, the clinical spectrum of this complex multisystem disease continues to evolve. One of the most important clinical events for patients with CF in the course of this disease is acute pulmonary exacerbation (PEx). Clinical and microbial epidemiology studies of CF PEx continue to provide important insight into the disease course, prognosis, and complications. This work has now led to several large-scale clinical trials designed to clarify the treatment paradigm for CF PEx. The primary goal of this review is to provide a summary and update of the pathophysiology, clinical and microbial epidemiology, outcome and treatment of CF PEx, biomarkers for exacerbation, and the impact of highly effective modulator therapy on these events moving forward.

The potential of volatile organic compound analysis for pathogen detection and disease monitoring in patients with cystic fibrosis

INTRODUCTION

Airway infection with pathogens and its associated pulmonary exacerbations (PEX) are the major causes of morbidity and premature death in cystic fibrosis (CF). Preventing or postponing chronic infections requires early diagnosis. However, limitations of conventional microbiology-based methods can hamper identification of exacerbations and specific pathogen detection. Analyzing volatile organic compounds (VOCs) in breath samples may be an interesting tool in this regard, as VOC-biomarkers can characterize specific airway infections in CF.

AREAS COVERED

We address the current achievements in VOC-analysis and discuss studies assessing VOC-biomarkers and fingerprints, i.e. a combination of multiple VOCs, in breath samples aiming at pathogen and PEX detection in people with CF (pwCF). We aim to provide bases for further research in this interesting field.

EXPERT OPINION

Overall, VOC-based analysis is a promising tool for diagnosis of infection and inflammation with potential to monitor disease progression in pwCF. Advantages over conventional diagnostic methods, including easy and non-invasive sampling procedures, may help to drive prompt, suitable therapeutic approaches in the future. Our review shall encourage further research, including validation of VOC-based methods. Specifically, longitudinal validation under standardized conditions is of interest in order to ensure repeatability and enable inclusion in CF diagnostic routine.

The Use of Artificial Sputum Media to Enhance Investigation and Subsequent Treatment of Cystic Fibrosis Bacterial Infections

In cystic fibrosis (CF), mutations in the CF transmembrane conductance regulator protein reduce ionic exchange in the lung, resulting in thicker mucus, which impairs mucociliary function, airway inflammation and infection. The mucosal and nutritional environment of the CF lung is inadequately mimicked by commercially available growth media, as it lacks key components involved in microbial pathogenesis. Defining the nutritional composition of CF sputum has been a long-term goal of in vitro research into CF infections to better elucidate bacterial growth and infection pathways. This narrative review highlights the development of artificial sputum medium, from a viable in vitro method for understanding bacterial mechanisms utilised in CF lung, to uses in the development of antimicrobial treatment regimens and examination of interactions at the epithelial cell surface and interior by the addition of host cell layers. The authors collated publications based on a PubMed search using the key words: “artificial sputum media” and “cystic fibrosis”. The earliest iteration of artificial sputum media were developed in 1997. Formulations since then have been based either on published data or chemically derived from extracted sputum. Formulations contain combinations of mucin, extracellular DNA, iron, amino acids, and lipids. A valuable advantage of artificial sputum media is the ability to standardise media composition according to experimental requirements.

Use of mucoactive agents in cystic fibrosis: A consensus survey of Italian specialists

Background

The goal of mucoactive therapies in cystic fibrosis (CF) is to enhance sputum clearance and to reduce a progressive decline in lung function over the patient's lifetime. We aimed to investigate the level of consensus among specialists from Italian CF Centers on appropriateness of therapeutic use of dornase alfa (rhDNase) for CF patients.

Method

A consensus on appropriate prescribing in CF mucoactive agents was appraised by an online Delphi method, based on a panel of 27 pulmonologists, coordinated by a Scientific Committee of six experts in medical care of patients with CF.

Results

Full or very high consensus was reached on several issues related to therapeutic use of dornase alfa for CF patients in clinical practice.

Conclusions

The consensus reached on a number of topics regarding use of mucoactive agents in patients with CF can help guide clinicians in daily practice based on expert experience and define the most appropriate therapeutic strategy for the individual patient.

Immunoglobulin A Mucosal Immunity and Altered Respiratory Epithelium in Cystic Fibrosis

The respiratory epithelium represents the first chemical, immune, and physical barrier against inhaled noxious materials, particularly pathogens in cystic fibrosis. Local mucus thickening, altered mucociliary clearance, and reduced pH due to CFTR protein dysfunction favor bacterial overgrowth and excessive inflammation. We aimed in this review to summarize respiratory mucosal alterations within the epithelium and current knowledge on local immunity linked to immunoglobulin A in patients with cystic fibrosis.

Inflammation biomarkers in sputum for clinical trials in cystic fibrosis: current understanding and gaps in knowledge

RATIONALE

Sputum biomarkers hold promise as a direct measure of inflammation within the cystic fibrosis (CF) lung, but variability in study design and sampling methodology have limited their use. A full evaluation of the reliability, validity and clinical relevance of individual biomarkers is required to optimise their use within CF clinical research.

OBJECTIVES

A biomarker Special Interest Working Group was established within the European Cystic Fibrosis Society-Clinical Trials Network Standardisation Committee, to perform a review of the evidence regarding sputum biomarkers in CF.

METHODS

From the 139 included articles, we identified 71 sputum biomarkers to undergo evaluation of their clinimetric properties, responsiveness, discriminant, concurrent and convergent validity.

RESULTS

Current evidence confirms the potential of sputum biomarkers as outcome measures in clinical trials. Inconsistency in responsiveness, concurrent and convergent validity require further research into these markers and processing standardisation before translation into wider use. Of the 71 biomarkers identified, Neutrophil Elastase (NE), IL-8, TNF-α and IL-1β, demonstrated validity and responsiveness to be currently considered for use in clinical trials. Other biomarkers show future promise, including IL-6, calprotectin, HMGB-1 and YKL-40.

CONCLUSION

A concerted international effort across the cystic fibrosis community is needed to promote high quality biomarker trial design, establish large population-based biomarker studies, and work together to create standards for collection, storage and analysis of sputum biomarkers.

Neutrophil Elastase and Chronic Lung Disease

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

SPLUNC1: a novel marker of cystic fibrosis exacerbations

Acute pulmonary Exacerbations (AE) are episodes of clinical worsening in cystic fibrosis (CF), often precipitated by infection. Timely detection is critical to minimise morbidity and lung function declines associated with acute inflammation during AE. Based on our previous observations that airway protein Short Palate Lung Nasal epithelium Clone 1 (SPLUNC1) is regulated by inflammatory signals, we investigated the use of SPLUNC1 fluctuations to diagnose and predict AE in CF.We enrolled CF participants from two independent cohorts to measure AE markers of inflammation in sputum and recorded clinical outcomes for a 1-year follow-up period.SPLUNC1 levels were high in healthy controls (n=9, 10.7 μg mL^-1), and significantly decreased in CF participants without AE (n=30, 5.7 μg mL^-1, p=0.016). SPLUNC1 levels were 71.9% lower during AE (n=14, 1.6 μg mL^-1, p=0.0034) regardless of age, sex, CF-causing mutation, or microbiology findings. Cytokines Il-1β and TNFα were also increased in AE, whereas lung function did not consistently decrease. Stable CF participants with lower SPLUNC1 levels were much more likely to have an AE at 60 days (HR: 11.49, Standard Error: 0.83, p=0.0033). Low-SPLUNC1 stable participants remained at higher AE risk even one year after sputum collection (HR: 3.21, Standard Error: 0.47, p=0.0125). SPLUNC1 was downregulated by inflammatory cytokines and proteases increased in sputum during AE.In acute CF care, low SPLUNC1 levels could support a decision to increase airway clearance or to initiate pharmacological interventions. In asymptomatic, stable patients, low SPLUNC1 levels could inform changes in clinical management to improve long-term disease control and clinical outcomes in CF.

CF Fungal Disease in the Age of CFTR Modulators

Fungi are increasingly recognised to have a significant role in the progression of lung disease in Cystic fibrosis with Aspergillus fumigatus the most common fungus isolated during respiratory sampling. The emergence of novel CFTR modulators has, however, significantly changed the outlook of disease progression in CF. In this review we discuss what impact novel CFTR modulators will have on fungal lung disease and its management in CF. We discuss how CFTR modulators affect antifungal innate immunity and consider the impact of Ivacaftor on fungal disease in individuals with gating mutations. We further review the increasing complication of drug-drug interactions with concurrent use of azole antifungal medication and highlight key unknowns that require addressing to fully understand the impact of CFTR modulators on fungal disease.

Changes in Airway Microbiome and Inflammation with Ivacaftor Treatment in Patients with Cystic Fibrosis and the G551D Mutation

Rationale: Modulation of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein improves clinical outcomes in patients with CF and specific CFTR genetic mutations. It remains unclear how improving CFTR function modifies existing airway infection and inflammation.Objectives: To compare sputum microbiome and markers of inflammation before and after 6 months of ivacaftor treatment.Methods: The study included 31 people with CF, ages 10 years and older, with at least one G551D CFTR allele and an forced expiratory volume in 1 second (FEV₁) of 40% predicted or greater who were enrolled in the GOAL (G551D Observational) study. Sputum samples were collected either by induction (n = 14) or by spontaneous expectoration (n = 17) before and 6 months after initiation of ivacaftor. Changes in bacterial community indices by sequencing of 16S rRNA amplicons, total and specific bacterial load, and a panel of proteases, antiproteases, and inflammatory cytokines were determined.Results: The cohort that spontaneously expectorated sputum had a lower FEV₁, a higher proportion with Pseudomonas aeruginosa infection, and higher concentrations of sputum inflammatory markers compared with the cohort that provided sputum by induction. Although the overall cohort experienced significant improvements in FEV₁ and reductions in sweat chloride, no significant changes in bacterial diversity, specific bacterial pathogens, or markers of inflammation were observed in these subjects. Neither total bacterial load nor presence of Pseudomonas changed significantly between paired samples with ivacaftor treatment. Younger patients experienced more shifts in their microbial communities than older patients.Conclusions: In this multicenter cohort, 6 months of ivacaftor treatment were not associated with significant changes in airway microbial communities or measures of inflammation. These data suggest that concomitant antimicrobial and antiinflammatory treatments will still be needed to manage airway disease in patients with CF treated with highly effective CFTR modulator therapy, especially in older patients with more advanced disease.

Safety of research bronchoscopy with BAL in stable adult patients with cystic fibrosis

Data on adverse events from research bronchoscopy with bronchoalveolar lavage (BAL) in patients with cystic fibrosis (CF) is lacking. As research bronchoscopy with BAL is useful for isolation of immune cells and investigation of CF lung microbiome, we sought to investigate the safety of bronchoscopy in adult patients with CF. Between November 2016 and September 2019, we performed research bronchoscopies on CF subjects (32) and control subjects (82). Control subjects were nonsmokers without respiratory disease. CF subjects had mild or moderate obstructive lung disease (FEV1 > 50% predicted) and no evidence of recent CF pulmonary exacerbation. There was no significant difference in the age or sex of each cohort. Neither group experienced life threatening adverse events. The number of adverse events was similar between CF and control subjects. The most common adverse events were sore throat and cough, which occurred at similar frequencies in control and CF subjects. Fever and headache occurred more frequently in CF subjects. However, the majority of fevers were seen in CF subjects with FEV1 values below 65% predicted. We found that CF subjects had similar adverse event profiles following research bronchoscopy compared to healthy subjects. While CF subjects had a higher rate of fevers, this adverse event occurred with greater frequency in CF subjects with lower FEV1. Our data demonstrate that research bronchoscopy with BAL is safe in CF subjects and that safety profile is improved if bronchoscopies are limited to subjects with an FEV1 > 65% predicted.

The Phosphodiesterase Inhibitor Ensifentrine Reduces Production of Proinflammatory Mediators in Well Differentiated Bronchial Epithelial Cells by Inhibiting PDE4

Cystic fibrosis (CF) is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel that impair airway salt and fluid secretion. Excessive release of proinflammatory cytokines and chemokines by CF bronchial epithelium during airway infection leads to chronic inflammation and a slow decline in lung function; thus, there is much interest in finding safe and effective treatments that reduce inflammation in CF. We showed previously that the cyclic nucleotide phosphodiesterase (PDE) inhibitor ensifentrine (RPL554; Verona Pharma) stimulates the channel function of CFTR mutants with abnormal gating and also those with defective trafficking that are partially rescued using a clinically approved corrector drug. PDE inhibitors also have known anti-inflammatory effects; therefore, we examined whether ensifentrine alters the production of proinflammatory cytokines in CF bronchial epithelial cells. Ensifentrine reduced the production of monocyte chemoattractant protein-1 and granulocyte monocyte colony-stimulating factor (GM-CSF) during challenge with interleukin-1β Comparing the effect of ensifentrine with milrinone and roflumilast, selective PDE3 and PDE4 inhibitors, respectively, demonstrated that the anti-inflammatory effect of ensifentrine was mainly due to inhibition of PDE4. Beneficial modulation of GM-CSF was further enhanced when ensifentrine was combined with low concentrations of the β 2-adrenergic agonist isoproterenol or the corticosteroid dexamethasone. The results indicate that ensifentrine may have beneficial anti-inflammatory effects in CF airways particularly when used in combination with β 2-adrenergic agonists or corticosteroids. SIGNIFICANCE STATEMENT: Airway inflammation that is disproportionate to the burden of chronic airway infection causes much of the pathology in the cystic fibrosis (CF) lung. We show here that ensifentrine beneficially modulates the release of proinflammatory factors in well differentiated CF bronchial epithelial cells that is further enhanced when combined with β2-adrenergic agonists or low-concentration corticosteroids. The results encourage further clinical testing of ensifentrine, alone and in combination with β2-adrenergic agonists or low-concentration corticosteroids, as a novel anti-inflammatory therapy for CF.

MicroRNA-155 from sputum as noninvasive biomarker for diagnosis of active pulmonary tuberculosis

Objectives

Tuberculosis (TB), caused by Mycobacterium tuberculosis, is a widespread infectious disease around the world. Early diagnosis is always important in order to avoid spreading. At present, many studies have confirmed that microRNA (miRNA) could be a useful tool for diagnosis. This study aimed to evaluate whether miRNAs could be regarded as a noninvasive diagnosis biomarker from sputum for pulmonary tuberculosis (PTB).

Materials and Methods

The M. tuberculosis strain H37Rv was incubated and cultured with human macrophage line THP-1. The total RNA was extracted from the THP-1 cells for detection. Six increased expressions of miRNAs were selected by miRNA microarray chips and the miRNAs were confirmed by qRT-PCR in the M. tuberculosis infection cell model. At last, the efficiency of other methods was compared with using miRNA.

Results

Only miR-155 showed a better diagnostic value for PTB than the other five miRNAs to distinguish PTB from non-PTB, including pneumonia, lung cancer, and unexplained pulmonary nodules. Next, we detected and analyzed the results of 68 PTB patients and 122 non-PTB, the sensitivity and specificity of miR-155 detection was 94.1% and 87.7%, respectively. It was higher than sputum smear detection and anti-TB antibody detection. But slightly lower than ELISpot (97%, P=0.404). Interestingly, the ranking of sputum smear by Ziehl-Neelsen staining had positive correlation with the expression level of miR-155 in smear-positive sputum (R²=0.8443, P<0.05).

Conclusion

Our research suggested that miR-155 may be an efficiency biomarker for active PTB diagnosis and bacteria-loads evaluation.

Single-Cell Transcriptional Archetypes of Airway Inflammation in Cystic Fibrosis

Rationale: Cystic fibrosis (CF) is a life-shortening, multisystem hereditary disease caused by abnormal chloride transport. CF lung disease is driven by innate immune dysfunction and exaggerated inflammatory responses that contribute to tissue injury. To define the transcriptional profile of this airway immune dysfunction, we performed the first single-cell transcriptome characterization of CF sputum.Objectives: To define the transcriptional profile of sputum cells and its implication in the pathogenesis of immune function and the development of CF lung disease.Methods: We performed single-cell RNA sequencing of sputum cells from nine subjects with CF and five healthy control subjects. We applied novel computational approaches to define expression-based cell function and maturity profiles, herein called transcriptional archetypes.Measurements and Main Results: The airway immune cell repertoire shifted from alveolar macrophages in healthy control subjects to a predominance of recruited monocytes and neutrophils in CF. Recruited lung mononuclear phagocytes were abundant in CF and were separated into the following three archetypes: activated monocytes, monocyte-derived macrophages, and heat shock-activated monocytes. Neutrophils were the most prevalent in CF, with a dominant immature proinflammatory archetype. Although CF monocytes exhibited proinflammatory features, both monocytes and neutrophils showed transcriptional evidence of abnormal phagocytic and cell-survival programs.Conclusions: Our findings offer an opportunity to understand subject-specific immune dysfunction and its contribution to divergent clinical courses in CF. As we progress toward personalized applications of therapeutic and genomic developments, we hope this inflammation-profiling approach will enable further discoveries that change the natural history of CF lung disease.

Dysregulated signalling pathways in innate immune cells with cystic fibrosis mutations

Cystic fibrosis (CF) is one of the most common life-limiting recessive genetic disorders in Caucasians, caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). CF is a multi-organ disease that involves the lungs, pancreas, sweat glands, digestive and reproductive systems and several other tissues. This debilitating condition is associated with recurrent lower respiratory tract bacterial and viral infections, as well as inflammatory complications that may eventually lead to pulmonary failure. Immune cells play a crucial role in protecting the organs against opportunistic infections and also in the regulation of tissue homeostasis. Innate immune cells are generally affected by CFTR mutations in patients with CF, leading to dysregulation of several cellular signalling pathways that are in continuous use by these cells to elicit a proper immune response. There is substantial evidence to show that airway epithelial cells, neutrophils, monocytes and macrophages all contribute to the pathogenesis of CF, underlying the importance of the CFTR in innate immune responses. The goal of this review is to put into context the important role of the CFTR in different innate immune cells and how CFTR dysfunction contributes to the pathogenesis of CF, highlighting several signalling pathways that may be dysregulated in cells with CFTR mutations.

Designing Clinical Trials for Anti-Inflammatory Therapies in Cystic Fibrosis

The inflammatory response in the CF airway begins early in the disease process and becomes persistent through life in most patients. Inflammation, which is predominantly neutrophilic, worsens airway obstruction and plays a critical role in the development of structural lung damage. While cystic fibrosis transmembrane regulator modulators will likely have a dramatic impact on the trajectory of CF lung disease over the coming years, addressing other important aspects of lung disease such as inflammation will nevertheless remain a priority. Considering the central role of neutrophils and their products in the inflammatory response, potential therapies should ultimately affect neutrophils and their products. The ideal anti-inflammatory therapy would exert a dual effect on the pro-inflammatory and pro-resolution arms of the inflammatory cascade, both of which contribute to dysregulated inflammation in CF. This review outlines the key factors to be considered in the design of clinical trials evaluating anti-inflammatory therapies in CF. Important lessons have been learned from previous clinical trials in this area and choosing the right efficacy endpoints is key to the success of any anti-inflammatory drug development program. Identifying and validating non-invasive biomarkers, novel imaging techniques and sensitive lung function tests capable of monitoring disease activity and therapeutic response are important areas of research and will be useful for the design of future anti-inflammatory drug trials.

Methods for Extraction and Detection of Pf Bacteriophage DNA from the Sputum of Patients with Cystic Fibrosis

Background: There is increasing interest in the pulmonary microbiome's bacterial and viral communities, particularly in the context of chronic airway infections in cystic fibrosis (CF). However, the isolation of microbial DNA from the sputum from patients with CF is technically challenging and the optimal protocols for the analysis of viral species, including bacteriophage, from clinical samples remains difficult. Materials and Methods: In this study, we evaluate a set of methods developed for processing and analyzing sputum from patients with CF with the goal of detecting Pf bacteriophage virion-derived nucleic acid. We evaluate the impact of bead beating, deoxyribonuclease digestion, and heating steps in these protocols focusing on the quantitative assessment of Pseudomonas aeruginosa and Pf bacteriophage in sputum. Results: Based on these comparative data, we describe an optimized protocol for processing sputum from patients with CF and isolating DNA for polymerase chain reaction or sequencing-based studies. Conclusion: These studies demonstrate the assessment of a specific bacteriophage and bacteria in sputum from patients with CF.

Changing Prevalence of Lower Airway Infections in Young Children with Cystic Fibrosis

Rationale: Historical studies suggest that airway infection in cystic fibrosis initiates with Staphylococcus aureus and Haemophilus influenzae, with later emergence of Pseudomonas aeruginosa. Aspergillus species are regarded as relatively infrequent, late-occurring infections.Objectives: To assess the prevalence and change in prevalence of early lower airway infections in a modern cohort of children with cystic fibrosis.Methods: All infants diagnosed with cystic fibrosis after newborn screening participating in the Australian Respiratory Early Surveillance Team for Cystic Fibrosis (AREST CF) cohort study between 2000 and 2018 were included. Participants prospectively underwent BAL at 3-6 months, 1 year, and annually up to 6 years of age. Lower airway infection prevalence was described. Changes in prevalence patterns were assessed longitudinally using generalized estimating equations controlling for age and repeated visits.Measurements and Main Results: A total of 380 infants underwent 1,759 BALs. The overall prevalence and median age of first acquisition of the most common infections were as follows: S. aureus, 11%, 2.5 years; P. aeruginosa, 8%, 2.4 years; Aspergillus species, 11%, 3.2 years; and H. influenzae, 9%, 3.1 years. During the study, a significant decrease in prevalence of P. aeruginosa (P < 0.001) and S. aureus (P < 0.001) was observed with a significant change toward more aggressive treatment. Prevalence of Aspergillus infections did not significantly change (P = 0.669).Conclusions: Aspergillus species and P. aeruginosa are commonly present in the lower airways from infancy. The decrease in prevalence of P. aeruginosa and S. aureus since 2000, coinciding with a more aggressive therapeutic approach, has resulted in Aspergillus becoming the most commonly isolated pathogen in young children. Further research is warranted to understand the implication of these findings.

Abnormal pro-gly-pro pathway and airway neutrophilia in pediatric cystic fibrosis

BACKGROUND

Proline-glycine-proline (PGP) is a bioactive fragment of collagen generated by the action of matrix metalloproteinase-9 (MMP-9) and prolylendopeptidase (PE), and capable of eliciting neutrophil chemotaxis and epithelial remodelling. PGP is normally then degraded by leukotriene A₄ hydrolase (LTA₄H) to limit inflammation and remodelling. This study hypothesized that early and persistent airway neutrophilia in Cystic Fibrosis (CF) may relate to abnormalities in the PGP pathway and sought to understand underlying mechanisms.

METHODS

Broncho-alveolar lavage (BAL) fluid was obtained from 38 CF (9 newborns and 29 older children) and 24 non-CF children. BAL cell differentials and levels of PGP, MMP-9, PE and LTA₄H were assessed.

RESULTS

Whilst PGP was present in all but one of the older CF children tested, it was absent in non-CF controls and the vast majority of CF newborns. BAL levels of MMP-9 and PE were elevated in older children with CF relative to CF newborns and non-CF controls, correlating with airway neutrophilia and supportive of PGP generation. Furthermore, despite extracellular LTA₄H commonly being greatly elevated concomitantly with inflammation to promote PGP degradation, this was not the case in CF children, potentially owing to degradation by neutrophil elastase.

CONCLUSIONS

A striking imbalance between PGP-generating and -degrading enzymes enables PGP accumulation in CF children from early life and potentially supports airway neutrophilia.

Secretory IgA-mediated immune response in saliva and early detection of Pseudomonas aeruginosa in the lower airways of pediatric cystic fibrosis patients

Pseudomonas aeruginosa (Pa) detection in the paranasal sinuses may help to prevent or postpone bacterial aspiration to the lower airways (LAW) and chronic lung infection in cystic fibrosis (CF). We assessed the ability of an ELISA test for measurement of specific Pa secretory IgA (sIgA) in saliva (a potential marker of sinus colonization) to early detect changes in the Pa LAW status (indicated by microbiological sputum or cough swab culture and specific serum IgG levels) of 65 patients for three years, in different investigation scenarios. Increased sIgA levels were detected in saliva up to 22 months before changes in culture/serology. Patients who remained Pa-positive had significantly increased sIgA levels than patients who remained Pa-negative, both at the baseline (39.6 U/mL vs. 19.2 U/mL; p = 0.02) and at the end of the follow-up (119.4 U/mL vs. 25.2 U/mL; p < 0.001). No association was found between sIgA levels in saliva and emergence or recurrence of Pa in the LAW. A positive median sIgA result in the first year of follow-up implied up to 12.5-fold increased risk of subsequent Pa exposure in the LAW. Our test detected early changes in the P. aeruginosa LAW status and risk of exposure to P. aeruginosa in the LAW with two years in advance. Comparison with sinus culture is needed to assess the test's ability to identify CF patients in need of a sinus approach for Pa investigation, which could provide opportunities of Pa eradication before its aspiration to the lungs.

A specialized method of sputum collection and processing for therapeutic interventions in cystic fibrosis

Cystic fibrosis (CF) lung disease is characterized by aggressive neutrophil-dominated inflammation mediated in large part by neutrophil elastase (NE), an omnivorous protease released by activated or disintegrating neutrophils and a key therapeutic target. To date, several short-term studies have shown that anti-NE compounds can inhibit NE and have anti-inflammatory effects. However, progression to large-scale or multicenter clinical trials has been hampered by the fact that the current gold standard methodology of evaluating airway NE inhibition, bronchoalveolar lavage (BAL), is invasive, difficult to standardize across sites and excludes those with severe lung disease. Attempts to utilize sputum that is either spontaneously expectorated (SS) or induced (IS) have been hindered by poor reproducibility, often due to the various processing methods employed. In this study, we evaluate TEmperature-controlled Two-step Rapid Isolation of Sputum (TETRIS), a specialized method for the acquisition and processing of SS and IS. Using TETRIS, we show for the first time that NE activity and cytokine levels are comparable in BAL, SS and IS samples taken from the same people with CF (PWCF) on the same day once this protocol is used. We correlate biomarkers in TETRIS-processed IS and clinical outcome measures including FEV₁, and show stability and reproducible inhibition of NE over time in IS processed by TETRIS. The data offer a tremendous opportunity to evaluate prognosis and therapeutic interventions in CF and to study the full spectrum of people with PWCF, many of whom have been excluded from previous studies due to being unfit for BAL or unable to expectorate sputum.

Secretory IgA response against Pseudomonas aeruginosa in the upper airways and the link with chronic lung infection in cystic fibrosis

We assessed the diagnostic ability of an enzyme-linked immunosorbent assay test for measurement of specific secretory IgA (sIgA) in saliva to identify cystic fibrosis (CF) patients with Pseudomonas aeruginosa chronic lung infection and intermittent lung colonization. A total of 102 Brazilian CF patients and 53 healthy controls were included. Specific serum IgG response was used as a surrogate to distinguish CF patients according to their P. aeruginosa colonization/infection status. The rate of sIgA positivity was 87.1% in CF chronically infected patients (median value = 181.5 U/mL), 48.7% in intermittently colonized patients (median value = 45.8 U/mL) and 21.8% in free of infection patients (median value = 22.1 U/mL). sIgA levels in saliva were significantly associated with serum P. aeruginosa IgG and microbiological culture results. The sensitivity, specificity, PPV and NPV for differentiation between presence and absence of chronic lung infection were 87%, 63%, 51% and 92%, respectively. Measurement of sIgA in saliva may be used for screening patients in risk of developing P. aeruginosa chronic lung infection in CF and possibly also for paranasal sinusitis, and, most importantly, to efficiently rule out chronic P. aeruginosa lung infection.

Volatile molecules from bronchoalveolar lavage fluid can 'rule-in' Pseudomonas aeruginosa and 'rule-out' Staphylococcus aureus infections in cystic fibrosis patients

Respiratory infections caused by Pseudomonas aeruginosa and Staphylococcus aureus are the leading cause of morbidity and mortality in cystic fibrosis (CF) patients. The authors aimed to identify volatile biomarkers from bronchoalveolar lavage (BAL) samples that can guide breath biomarker development for pathogen identification. BAL samples (n = 154) from CF patients were analyzed using two-dimensional gas chromatography time-of-flight mass spectrometry. Random Forest was used to select suites of volatiles for identifying P. aeruginosa-positive and S. aureus-positive samples using multiple infection scenarios and validated using test sets. Using nine volatile molecules, we differentiated P. aeruginosa-positive (n = 7) from P. aeruginosa-negative (n = 53) samples with an area under the receiver operating characteristic curve (AUROC) of 0.86 (95% CI 0.71–1.00) and with positive and negative predictive values of 0.67 (95% CI 0.38–0.75) and 0.92 (95% CI 0.88–1.00), respectively. We were also able to discriminate S. aureus-positive (n = 15) from S. aureus-negative (n = 45) samples with an AUROC of 0.88 (95% CI 0.79-1.00) using eight volatiles and with positive and negative predictive values of 0.86 (95% CI 0.61–0.96) and 0.70 (95% CI 0.61–0.75), respectively. Prospective validation of identified biomarkers as screening tools in patient breath may lead to clinical application.

Biomarkers of inflammation in infants with cystic fibrosis

Background

There are urgent needs for clinically relevant biomarkers to identify children with cystic fibrosis (CF) at risk for more progressive lung disease and to serve as outcome measures for clinical trials. Our objective was to investigate three targeted biomarkers in a population of asymptomatic CF infants.

Methods

Urine, blood and lung function data were collected for 2 years from clinically stable infants diagnosed with CF by newborn screening. A subset of CF infants had bronchoscopy with lavage performed at 6 months and 1 year. Urine was collected quarterly from healthy control infants. Expectorated sputum and urine were collected quarterly for 2 years from clinically stable CF adults. Desmosine, club cell secretory protein (CCSP) and cathepsin B concentrations were measured and compared. Mixed effects models were used to identify associations between biomarker concentrations and clinical characteristics. Receiver operator characteristic curves were generated to investigate the sensitivity and specificity of the biomarkers.

Results

Urinary cathepsin B was significantly higher in CF infants compared to healthy infants (p = 0.005). CF infant airway and urinary cathepsin B concentrations were significantly lower compared to adult CF subjects (p = 0.002 & p = 0.022, respectively). CF infant airway CCSP was significantly higher than adult CF subjects (p < 0.001). There was a significant correlation between CF infant plasma CCSP and BALF CCSP (p = 0.046). BALF CCSP was negatively associated with IL-8 (p = 0.017). There was no correlation between biomarker concentration and FEV_0.5.

Conclusions

Cathepsin B and CCSP show promise as biomarkers of inflammation in CF infants. Further study is needed.

Electronic supplementary material

The online version of this article (10.1186/s12931-017-0713-8) contains supplementary material, which is available to authorized users.

Chemoattractants and cytokines in primary ciliary dyskinesia and cystic fibrosis: key players in chronic respiratory diseases

Patients with primary ciliary dyskinesia (PCD) and cystic fibrosis (CF), two inherited disorders, suffer from recurrent airway infections characterized by persistent bacterial colonization and uncontrollable inflammation. Although present in high counts, neutrophils fail to clear infection in the airways. High levels of C-X-C motif chemokine ligand 8/interleukin-8 (CXCL8/IL-8), the most potent chemokine to attract neutrophils to sites of infection, are detected in the sputum of both patient groups and might cause the high neutrophil influx in the airways. Furthermore, in CF, airway neutrophils are highly activated because of the genetic defect and the high levels of proinflammatory chemoattractants and cytokines (e.g., CXCL8/IL-8, tumor necrosis factor-α and IL-17). The overactive state of neutrophils leads to lung damage and fuels the vicious circle of infection, excessive inflammation and tissue damage. The inflammatory process in CF airways is well characterized, whereas the lung pathology in PCD is far less studied. The knowledge of CF lung pathology could be useful to guide molecular investigations of the inflammatory processes in PCD lungs. Current available therapies can not completely remedy the chronic airway infections in these diseases. This review gives an overview of the role that chemoattractants and cytokines play in these neutrophil-dominated lung pathologies. Finally, the most frequently applied treatments in CF and PCD and new experimental therapies to reduce neutrophil-dominated airway inflammation are described.

Is bronchoscopy an obsolete tool in cystic fibrosis? The role of bronchoscopy in cystic fibrosis and its clinical use

Cystic fibrosis (CF) is a progressive life threatening multisystem genetic disease which affects the CF transmembrane conductance regulator channel. Respiratory causes remain the most common mortality in CF. With the onset of newborn screening, initiating treatments both for prophylaxis and disease management, optimizing nutritional support, and developing therapies targeting CF transmembrane conductance regulator protein, this has significantly changed the face of managing this devastating disease. Bronchoscopy and related procedures such as bronchoalveolar lavage (BAL), transbronchial biopsies, and protected brush sampling have been looked at in the management of CF as patients with CF continue to live longer with the help of newer therapies, the microbiome in the lung becomes less diverse along with increased occurrences for noninfectious causes of airway diseases. Though bronchoscopy has been used in conjunction with other modalities such as computed tomography and sputum induction providing a better understanding of the progression of the disease, it still remains valuable in the diagnosis and management of CF.

Multiparameter Single Cell Profiling of Airway Inflammatory Cells

Airway diseases affect over 7% of the U.S. population and millions of patients worldwide. Asthmatic patients have wide variation in clinical severity with different clinical and physiologic manifestations of disease that may be driven by distinct biologic mechanisms. Further, the immunologic underpinnings of this complex trait disease are heterogeneous and treatment success depends on defining subgroups of asthmatics. Because of the limited availability and number of cells from the lung, the active site, in-depth investigation has been challenging. Recent advances in technology support transcriptional analysis of cells from induced sputum. Flow cytometry studies have described cells present in the sputum but a detailed analysis of these subsets is lacking. Mass cytometry or CyTOF (Cytometry by Time-Of-Flight) offers tremendous opportunities for multiparameter single cell analysis. Experiments can now allow detection of up to ∼40 markers to facilitate unprecedented multidimensional cellular analyses. Here we demonstrate the use of CyTOF on primary airway samples obtained from well-characterized patients with asthma and cystic fibrosis. Using this technology, we quantify cellular frequency and functional status of defined cell subsets. Our studies provide a blueprint to define the heterogeneity among subjects and underscore the power of this single cell method to characterize airway immune status. © 2016 International Clinical Cytometry Society.

Hypertonic Saline Treatment of Cystic Fibrosis

Objective:

To review the literature concerning the use of hypertonic saline (HS) in patients with cystic fibrosis and explain the rationale for its use.

Data Sources:

A MEDLINE search was conducted through February 2007. Search terms included hypertonic saline, mucociliary clearance, cystic fibrosis, and human DNASE 1 protein. Additional data were identified through subsequent bibliographic reviews.

Study Selection And Data Extraction:

All articles in English identified from the data sources were evaluated. Pertinent studies using HS in patients with cystic fibrosis were included in the analysis.

Data Synthesis:

Cystic fibrosis is caused by a deficiency in the cystic fibrosis transmembrane regulator gene, resulting in reduced chloride secretion and excessive sodium absorption. The most significant changes are seen in the airway lumen of the lungs. HS has been shown to improve mucociliary clearance versus placebo. A short-term efficacy trial showed a modest and variable increase in forced expiratory volume in 1 second (FEV1) over a 2 week period (15.0 ± 16.0% from baseline vs 2.8 ± 13.1% with HS 6% and NaCI 0.9%, respectively; p = 0.004). A long-term efficacy trial of either HS 7% or NaCI 0.9% twice daily for 48 weeks has shown a modest sustained improvement in FEV1 and a significantly increased exacerbation-free survival rato (76% vs 62% for HS 7% and NaCI 0.9%, respectively; p = 0.03).

Conclusions:

HS preceded by a bronchodilator is an inexpensive, safe, effective additional therapy in cystic fibrosis patients with stable lung function. Its use has been associated with a modest improvement in lung function and reduced frequency of pulmonary exacerbations.

Severe disease in Cystic Fibrosis and fecal calprotectin levels

Fecal calprotectin (FC) is used to asses the presence of intestinal inflammation also in patients with Cystic Fibrosis (CF) and recent studies showed a correlation between bowel and lung disease in these patients. The aim of this study was to analyze the levels of FC in CF and correlate them with different phenotypes of disease. We enrolled a cohort of 54 CF patients and 50 healthy controls. In these patients, calprotectin has been assayed on a stools sample using an ELISA kit. In all patients we analyzed, FC levels were elevated above the cut-off value and significantly higher than in healthy controls. Among CF patients, FC was significantly higher in patients older than 18 years, with pancreatic insufficiency, underweight status, Pseudomonas Aeruginosa airways colonization, CF-related diabetes mellitus, reduced lung function, or high number of pulmonary exacerbations. These results suggest that in patients with CF, FC levels are not only influenced by the CF enteropathy but also by the severity of the genetic disease. Since we found higher FC levels in patients with a severe phenotype (P. Aeruginosa airways colonization, FEV1<50% of predicted, pancreatic insufficiency, underweight status,) we suggest that this marker could be useful to monitor longitudinally a clinical worsening.

Phase I Studies of Acebilustat: Pharmacokinetics, Pharmacodynamics, Food Effect, and CYP3A Induction

Acebilustat is a new once-daily oral antiinflammatory drug in development for treatment of cystic fibrosis (CF) and other diseases. It is an inhibitor of leukotriene A4 hydrolase; therefore, production of leukotriene B4 (LTB4) in biological fluids provides a direct measure of the pharmacodynamic (PD) response to acebilustat treatment. Here we compare the pharmacokinetics (PK) and PD between CF patients and healthy volunteers, and investigate the food effect and CYP3A4 induction in healthy volunteers. No significant differences between study populations were observed for peak plasma level (C_max ) or exposure (AUC). In healthy volunteers, a shift in time to C_max (T_max ) was observed after a high-fat meal, but there was no change in AUC. LTB4 production was reduced in the blood of both populations and in sputum from CF patients. Acebilustat did not induce CYP3A4. These results support continued clinical study of once-daily oral acebilustat in CF at doses of 50 and 100 mg.

Biomarkers for cystic fibrosis drug development

PURPOSE

To provide a review of the status of biomarkers in cystic fibrosis drug development, including regulatory definitions and considerations, a summary of biomarkers in current use with supportive data, current gaps, and future needs.

METHODS

Biomarkers are considered across several areas of CF drug development, including cystic fibrosis transmembrane conductance regulator modulation, infection, and inflammation.

RESULTS

Sweat chloride, nasal potential difference, and intestinal current measurements have been standardized and examined in the context of multicenter trials to quantify CFTR function. Detection and quantification of pathogenic bacteria in CF respiratory cultures (e.g.: Pseudomonas aeruginosa) are commonly used in early phase antimicrobial clinical trials, and to monitor safety of therapeutic interventions. Sputum (e.g.: neutrophil elastase, myeloperoxidase, calprotectin) and blood biomarkers (e.g.: C reactive protein, calprotectin, serum amyloid A) have had variable success in detecting response to inflammatory treatments.

CONCLUSIONS

Biomarkers are used throughout the drug development process in CF, and many have been used in early phase clinical trials to provide proof of concept, detect drug bioactivity, and inform dosing for later-phase studies. Advances in the precision of current biomarkers, and the identification of new biomarkers with 'omics-based technologies, are needed to accelerate CF drug development.

Throat Swabs and Sputum Culture as Predictors of P. aeruginosa or S. aureus Lung Colonization in Adult Cystic Fibrosis Patients

Background

Due to frequent infections in cystic fibrosis (CF) patients, repeated respiratory cultures are obtained to inform treatment. When patients are unable to expectorate sputum, clinicians obtain throat swabs as a surrogate for lower respiratory cultures. There is no clear data in adult subjects demonstrating the adequacy of throat swabs as a surrogate for sputum or BAL. Our study was designed to determine the utility of throat swabs in identifying lung colonization with common organisms in adults with CF.

Methods

Adult CF subjects (n = 20) underwent bronchoscopy with BAL. Prior to bronchoscopy, a throat swab was obtained. A sputum sample was obtained from subjects who were able to spontaneously expectorate. All samples were sent for standard microbiology culture.

Results

Using BAL as the gold standard, we found the positive predictive value for Pseudomonas aeruginosa to be 100% in both sputum and throat swab compared to BAL. However, the negative predictive value for P. aeruginosa was 60% and 50% in sputum and throat swab, respectively. Conversely, the positive predictive value for Staphylococcus aureus was 57% in sputum and only 41% in throat swab and the negative predictive value of S. aureus was 100% in sputum and throat swab compared to BAL.

Conclusions

Our data show that positive sputum and throat culture findings of P. aeruginosa reflect results found on BAL fluid analysis, suggesting these are reasonable surrogates to determine lung colonization with P. aeruginosa. However, sputum and throat culture findings of S. aureus do not appear to reflect S. aureus colonization of the lung.

In Vitro Analysis of Pseudomonas aeruginosa Virulence Using Conditions That Mimic the Environment at Specific Infection Sites

Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes chronic lung infection in patients with cystic fibrosis (CF) and acute systemic infections in severely burned patients and immunocompromised patients including cancer patients undergoing chemotherapy and HIV infected individuals. In response to the environmental conditions at specific infection sites, P. aeruginosa expresses certain sets of cell-associated and extracellular virulence factors that produce tissue damage. Analyzing the mechanisms that govern the production of these virulence factors in vitro requires media that closely mimic the environmental conditions within the infection sites. In this chapter, we review studies based on media that closely resemble three in vivo conditions, the thick mucus accumulated within the lung alveoli of CF patients, the serum-rich wound bed and the bloodstream. Media resembling the CF alveolar mucus include standard laboratory media supplemented with sputum obtained from CF patients as well as prepared synthetic mucus media formulated to contain the individual components of CF sputum. Media supplemented with serum or individual serum components have served as surrogates for the soluble host components of wound infections, while whole blood has been used to investigate the adaptation of pathogens to the bloodstream. Studies using these media have provided valuable information regarding P. aeruginosa gene expression in different host environments as varying sets of genes were differentially regulated during growth in each medium. The unique effects observed indicate the essential role of these in vitro media that closely mimic the in vivo conditions in providing accurate information regarding the pathogenesis of P. aeruginosa infections.

Cystic Fibrosis: Microbiology and Host Response

The earliest descriptions of lung disease in people with cystic fibrosis (CF) showed the involvement of 3 interacting pathophysiologic elements in CF airways: mucus obstruction, inflammation, and infection. Over the past 7 decades, our understanding of CF respiratory microbiology and inflammation has evolved with the introduction of new treatments, increased longevity, and increasingly sophisticated laboratory techniques. This article reviews the current understanding of infection and inflammation and their roles in CF lung disease. It also discusses how this constantly evolving information is used to inform current therapeutic strategies, measures and predictors of disease severity, and research priorities.