Recessively Inherited Deficiency of Secreted WFDC2 (HE4) Causes Nasal Polyposis and Bronchiectasis.

RATIONALE: Bronchiectasis is a pathological dilatation of the bronchi in the respiratory airways associated with environmental or genetic causes (e.g., cystic fibrosis, primary ciliary dyskinesia and primary immunodeficiency disorders), but most cases remain idiopathic. OBJECTIVES: To identify novel genetic defects in unsolved cases of bronchiectasis presenting with severe rhinosinusitis, nasal polyposis, and pulmonary Pseudomonas aeruginosa infection. METHODS: DNA was analyzed by next-generation or targeted Sanger sequencing. RNA was analyzed by quantitative PCR and single-cell RNA sequencing. Patient-derived, cells, cell cultures and secretions (mucus, saliva, seminal fluid) were analyzed by Western blotting and immunofluorescence microscopy, and mucociliary activity was measured. Blood serum was analyzed by electrochemiluminescence immunoassay. Protein structure and proteomic analyses were used to assess the impact of a disease-causing founder variant. MEASUREMENTS AND MAIN RESULTS: We identified bi-allelic pathogenic variants in WFDC2 in 11 individuals from 10 unrelated families originating from the United States, Europe, Asia, and Africa. Expression of WFDC2 was detected predominantly in secretory cells of control airway epithelium and also in submucosal glands. We demonstrate that WFDC2 is below the limit of detection in blood serum and hardly detectable in samples of saliva, seminal fluid, and airway surface liquid from WFDC2-deficient individuals. Computer simulations and deglycosylation assays indicate that the disease-causing founder variant p.Cys49Arg structurally hampers glycosylation and thus secretion of mature WFDC2. CONCLUSIONS: WFDC2 dysfunction defines a novel molecular etiology of bronchiectasis characterized by the deficiency of a secreted component of the airways. A commercially available blood test combined with genetic testing allows its diagnosis. This article is open access and distributed under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/).

The effect of discontinuing hypertonic saline or dornase alfa on mucociliary clearance in elexacaftor/tezacaftor/ivacaftor treated people with cystic fibrosis: The SIMPLIFY-MCC Study.

Many people with CF (pwCF) desire a reduction in inhaled treatment burden after initiation of elexacaftor/tezacaftor/ivacaftor. The randomized, open-label SIMPLIFY study showed that discontinuing hypertonic saline (HS) or dornase alfa (DA) was non-inferior to continuation of each treatment with respect to change in lung function over a 6-week period. In this SIMPLIFY substudy, we used gamma scintigraphy to determine whether discontinuation of either HS or DA was associated with deterioration in the rate of in vivo mucociliary clearance (MCC) in participants ≥12 years of age. While no significant differences in MCC endpoints were associated with HS discontinuation, significant improvement in whole and peripheral lung MCC was observed after discontinuing DA. These results suggest that pwCF on ETI with mild lung disease do not experience a subclinical deterioration in MCC that could later impact health outcomes after discontinuing HS, and in fact may benefit from improved MCC after stopping DA treatment.

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.

Alterations in lipids after initiation of highly effective modulators in people with cystic fibrosis.

Risk of cardiovascular disease (CVD) may be changing in people with cystic fibrosis (pwCF) with widespread use of highly effective modulator therapy (HEMT). We performed a retrospective analysis of patients who had lipids checked before and after initiation of ivacaftor or elexacaftor/tezacaftor/ivacaftor. We hypothesized that HEMT negatively impacts lipids (total cholesterol [TC], low-density lipoprotein [LDL], high-density lipoprotein [HDL], TC/HDL ratio). 41 adult patients were included. Paired t-tests showed statistically significant increases in TC (mean difference 16.3 mg/dL, p = 0.007, n = 40), LDL (mean difference 17.1 mg/dL, p < 0.001, n = 35), and TC/HDL ratio (mean difference 0.40, p = 0.014, n = 39) after HEMT initiation. HDL was unchanged (mean difference -1.5 mg/dL, p = 0.69, n = 39). Linear mixed models showed CF liver disease was associated with significantly blunted changes in TC and LDL. Family history of CVD risk factors was associated with significantly accentuated increases in TC and LDL. These data suggest a role for more lipid screening in pwCF.

Pleural Fluid Resolution Is Associated with Improved Survival in Patients with Malignant Pleural Effusion.

Malignant pleural effusion is associated with a poor prognosis and, while risk stratification models exist, prior studies have not evaluated pleural fluid resolution and its association with survival. We performed a retrospective review of patients diagnosed with malignant pleural effusion between 2013 and 2017, evaluating patient demographics, pleural fluid and serum composition, and procedural and treatment data using Cox regression analysis to evaluate associations with survival. In total, 123 patients were included in the study, with median survival from diagnosis being 4.8 months. Resolution of malignant pleural fluid was associated with a significant survival benefit, even when accounting for factors such as placement of an indwelling pleural catheter, anti-cancer therapy, pleural fluid cytology, cancer pheno/genotypes, and pleural fluid characteristics. Elevated fluid protein, placement of an indwelling pleural catheter, and treatment with targeted or hormone therapies were associated with pleural fluid resolution. We conclude that the resolution of pleural fluid accumulation in patients with malignant pleural effusion is associated with a survival benefit possibility representing a surrogate marker for treatment of the underlying metastatic cancer. These findings support the need to better understand the mechanism of fluid resolution in patients with malignant pleural effusion as well as the tumor-immune interplay occurring with the malignant pleural space.

Feasibility of free-breathing 19 F MRI image acquisition to characterize ventilation defects in CF and healthy volunteers at wash-in.

PURPOSE: To explore the feasibility of measuring ventilation defect percentage (VDP) using 19 F MRI during free-breathing wash-in of fluorinated gas mixture with postacquisition denoising and to compare these results with those obtained through traditional Cartesian breath-hold acquisitions. METHODS: Eight adults with cystic fibrosis and 5 healthy volunteers completed a single MR session on a Siemens 3T Prisma. 1 H Ultrashort-TE MRI sequences were used for registration and masking, and ventilation images with 19 F MRI were obtained while the subjects breathed a normoxic mixture of 79% perfluoropropane and 21% oxygen (O2 ). 19 F MRI was performed during breath holds and while free breathing with one overlapping spiral scan at breath hold for VDP value comparison. The 19 F spiral data were denoised using a low-rank matrix recovery approach. RESULTS: VDP measured using 19 F VIBE and 19 F spiral images were highly correlated (r = 0.84) at 10 wash-in breaths. Second-breath VDPs were also highly correlated (r = 0.88). Denoising greatly increased SNR (pre-denoising spiral SNR, 2.46 ± 0.21; post-denoising spiral SNR, 33.91 ± 6.12; and breath-hold SNR, 17.52 ± 2.08). CONCLUSION: Free-breathing 19 F lung MRI VDP analysis was feasible and highly correlated with breath-hold measurements. Free-breathing methods are expected to increase patient comfort and extend ventilation MRI use to patients who are unable to perform breath holds, including younger subjects and those with more severe lung disease.

Antibiotic Tolerance and Treatment Outcomes in Cystic Fibrosis Methicillin-Resistant Staphylococcus aureus Infections.

Methicillin-resistant Staphylococcus aureus (MRSA) is highly prevalent in U.S. cystic fibrosis (CF) patients and is associated with worse clinical outcomes in CF. These infections often become chronic despite repeated antibiotic therapy. Here, we assessed whether bacterial phenotypes, including antibiotic tolerance, can predict the clinical outcomes of MRSA infections. MRSA isolates (n = 90) collected at the incident (i.e., acute) and early infection states from 57 patients were characterized for growth rates, biofilm formation, hemolysis, pigmentation, and vancomycin tolerance. The resistance profiles were consistent with those in prior studies. Isolates from the early stage of infection were found to produce biofilms, and 70% of the isolates exhibited delta-hemolysis, an indicator of agr activity. Strong vancomycin tolerance was present in 24% of the isolates but was not associated with intermediate vancomycin susceptibility. There were no associations between these phenotypic measures, antibiotic tolerance, and MRSA clearance. Our research suggests that additional factors may be relevant for predicting the clearance of MRSA. IMPORTANCE Chronic MRSA infections remain challenging to treat in patients with cystic fibrosis (CF). The ability of the bacterial population to survive high concentrations of bactericidal antibiotics, including vancomycin, despite lacking resistance is considered one of the main reasons for treatment failures. The connection between antibiotic tolerance and treatment outcomes remains unexplored and can be crucial for prognosis and regimen design toward eradication. In this study, we measured the capacity of 90 MRSA isolates from CF patients to form vancomycin-tolerant persister cells and evaluated their correlation with the clinical outcomes. Additionally, various traits that could reflect the metabolism and/or virulence of those MRSA isolates were systematically phenotyped and included for their predictive power. Our research highlights that despite the importance of antibiotic tolerance, additional factors need to be considered for predicting the clearance of MRSA.

Dynamic Perfluorinated Gas MRI Shows Improved Lung Ventilation in People with Cystic Fibrosis after Elexacaftor/Tezacaftor/Ivacaftor: An Observational Study.

The availability of highly effective CFTR modulators is revolutionizing the treatment of cystic fibrosis (CF) and drastically improving outcomes. MRI-based imaging modalities are now emerging as highly sensitive endpoints, particularly in the setting of mild lung disease. Adult CF patients were recruited from a single center prior to starting treatment with E/T/I. The following studies were obtained before and after one month on treatment: spirometry, multiple breath nitrogen washout (MBW), 1H UTE MRI (structural images) and 19F MRI (ventilation images). Changes between visits were calculated, as were correlations between FEV1, lung clearance index (LCI), MRI structural scores, and MRI-based ventilation descriptors. Eight subjects had complete datasets for evaluation. Consistent with prior clinical trials, FEV1 and LCI improved after 28 days of E/T/I use. 1H UTE MRI detected improvements in bronchiectasis/airway wall thickening score and mucus plugging score after 28 days of therapy. 19F MRI demonstrated improvements in fractional lung volume with slow gas washout time (FLV↑tau2) and ventilation defect percentage (VDP). Improvements in FLV↑tau2 and VDP correlated with improvement in FEV1 (r = 0.81 and 0.86, respectively, p < 0.05). This observational study establishes the ability of 19F MRI and 1H UTE MRI to detect improvements in lung structure and function after E/T/I treatment. This study supports further development of 19F MRI and 1H UTE MRI as outcome measures for cystic fibrosis research and drug development.

Biomarkers of Airway Immune Homeostasis Differ Significantly with Generation of E-Cigarettes.

Rationale: Numerous studies have demonstrated that e-cigarettes can impact respiratory immune homeostasis; however, the extent of these effects remains an active area of investigation, and most previous studies were conducted with model systems or subjects exposed to third-generation e-cigarettes, such as vape pens and box mods. Objectives: Given the rise in popularity of nicotine-salt-containing pods and disposable e-cigarettes (fourth generation), we set out to better understand the respiratory effects of these newer e-cigarettes and compare their effects to early-generation devices. Methods: We collected induced sputum samples from a cohort of nonsmokers, smokers, third-generation e-cigarette users, and fourth-generation e-cigarette users (n = 20-30 per group) and evaluated the cellular and fluid-phase composition for markers of inflammation, host defense, and lung injury. Measurements and Main Results: Fourth-generation e-cigarette users had significantly more bronchial epithelial cells in the sputum, suggestive of airway injury. Concentrations of soluble intercellular adhesion molecule 1 (sICAM1) and soluble vascular cell adhesion molecule 1 (sVCAM1) were significantly lower in fourth-generation e-cigarette users in comparison with all other groups, and CRP (C-reactive protein), IFN-γ, MCP-1 (monocyte chemoattractant protein-1), MMP-2 (matrix metalloproteinase 2), uteroglobin, and VEGF (vascular endothelial growth factor) were significantly lower in fourth- versus third-generation e-cigarette users, suggestive of overall immune suppression in fourth-generation e-cigarette users. Predictive modeling also demonstrated clear separation between exposure groups, indicating that the overall mediator milieu is different between groups, particularly fourth-generation e-cigarette users. Conclusions: Our results indicate disrupted immune homeostasis in fourth-generation e-cigarette users and demonstrate that the biological effects of fourth-generation e-cigarette use are unique compared with those associated with previous-generation e-cigarettes.

Effect of airway clearance therapies on mucociliary clearance in adults with cystic fibrosis: A randomized controlled trial.

BACKGROUND: Cystic fibrosis (CF) is an inherited disorder causing impaired mucociliary clearance within the respiratory tract, and is associated with bronchiectasis, chronic respiratory infections, and early death. Airway clearance therapies have long been a cornerstone of management of individuals with CF, although evidence supporting their use is lacking. We designed a randomized controlled trial to quantitatively compare the effects of different forms of airway clearance on mucociliary clearance. METHODS: Three different physiotherapy methods to augment cough-clearance were studied in addition to cough-clearance alone: high-frequency chest-wall oscillating vest, oscillatory positive expiratory pressure, and whole-body vibration. We used gamma scintigraphy after inhalation of radiolabeled particles to quantify mucus clearance before, during, and after physiotherapy. As secondary endpoints, we measured concentrations of small molecules in exhaled breath that may impact mucus clearance. RESULTS: Ten subjects were enrolled and completed study procedures. No differences were identified between any method of airway clearance, including cough clearance alone. We did identify changes in certain small molecule concentrations in exhaled breath following airway clearance. CONCLUSIONS: Due to the limitations of this study, we do not believe the negative results suggest a change in clinical practice with regard to airway clearance. Findings pertaining to small molecules in exhaled breath may serve as future opportunities for study.

Mucus and mucus flake composition and abundance reflect inflammatory and infection status in cystic fibrosis.

BACKGROUND: Mucus hyperconcentration in cystic fibrosis (CF) lung disease is marked by increases in both mucin and DNA concentration. Additionally, it has been shown that half of the mucins present in bronchial alveolar lavage fluid (BALF) from preschool-aged CF patients are present in as non-swellable mucus flakes. This motivates us to examine the utility of mucus flakes, as well as mucin and DNA concentrations in BALF as markers of infection and inflammation in CF airway disease. METHODS: In this study, we examined the mucin and DNA concentration, as well as mucus flake abundance, composition, and biophysical properties in BALF from three groups; healthy adult controls, and two CF cohorts, one preschool aged and the other school aged. BALFs were characterized via refractometry, PicoGreen, immunofluorescence microscopy, particle tracking microrheology, and fluorescence image tiling. RESULTS: Mucin and DNA BALF concentrations increased progressively from healthy young adult controls to preschool-aged people and school-aged people with CF. Notably, mucin concentrations were increased in bronchoalveolar lavage fluid (BALF) from preschool-aged patients with CF prior to decreased pulmonary function. Infrequent small mucus flakes were identified in normal subjects. A progressive increase in the abundance of mucus flakes in preschool and school-aged CF patients was observed. Compositionally, MUC5B dominated flakes from normal subjects, whereas an increase in MUC5AC was observed in people with CF, reflected in a reduced flaked MUC5B/MUC5AC mucin ratio. CONCLUSION: These findings suggest mucus composition and flake properties are useful markers of inflammatory and infection-based changes in CF airways.

Cystic Fibrosis Airway Mucus Hyperconcentration Produces a Vicious Cycle of Mucin, Pathogen, and Inflammatory Interactions that Promotes Disease Persistence.

The dynamics describing the vicious cycle characteristic of cystic fibrosis (CF) lung disease, initiated by stagnant mucus and perpetuated by infection and inflammation, remain unclear. Here we determine the effect of the CF airway milieu, with persistent mucoobstruction, resident pathogens, and inflammation, on the mucin quantity and quality that govern lung disease pathogenesis and progression. The concentrations of MUC5AC and MUC5B were measured and characterized in sputum samples from subjects with CF (N = 44) and healthy subjects (N = 29) with respect to their macromolecular properties, degree of proteolysis, and glycomics diversity. These parameters were related to quantitative microbiome and clinical data. MUC5AC and MUC5B concentrations were elevated, 30- and 8-fold, respectively, in CF as compared with control sputum. Mucin parameters did not correlate with hypertonic saline, inhaled corticosteroids, or antibiotics use. No differences in mucin parameters were detected at baseline versus during exacerbations. Mucin concentrations significantly correlated with the age and sputum human neutrophil elastase activity. Although significantly more proteolytic cleavages were detected in CF mucins, their macromolecular properties (e.g., size and molecular weight) were not significantly different than control mucins, likely reflecting the role of S-S bonds in maintaining multimeric structures. No evidence of giant mucin macromolecule reflecting oxidative stress-induced cross-linking was found. Mucin glycomic analysis revealed significantly more sialylated glycans in CF, and the total abundance of nonsulfated O-glycans correlated with the relative abundance of pathogens. Collectively, the interaction of mucins, pathogens, epithelium, and inflammatory cells promotes proteomic and glycomic changes that reflect a persistent mucoobstructive, infectious, and inflammatory state.

Effect of lumacaftor-ivacaftor on mucociliary clearance and clinical outcomes in cystic fibrosis: Results from the PROSPECT MCC sub-study.

CFTR function is required for normal mucociliary clearance (MCC) and cough-assisted clearance (CC). Lumacaftor-ivacaftor is approved for use in people with cystic fibrosis (CF) carrying two copies of F508del-CFTR. In this observational study performed at four study sites, we characterized the effect of lumacaftor-ivacaftor on mucociliary and cough clearance and related this to other clinical and research endpoints after one month of treatment. Twenty-five adolescents and adults were enrolled. No effect on whole lung MCC was observed, but CC was significantly increased. Sweat chloride improved by 18 mEq/L in this group, indicating a modest restoration of CFTR activity, but no demonstrable change in FEV1 or lung clearance index was observed. We speculate that the modest effect of lumacaftor-ivacaftor on CFTR function was insufficient to yield an improvement in MCC.

Identification of Sputum Biomarkers Predictive of Pulmonary Exacerbations in COPD.

BACKGROUND: Improved understanding of the pathways associated with airway pathophysiologic features in COPD will identify new predictive biomarkers and novel therapeutic targets. RESEARCH QUESTION: Which physiologic pathways are altered in the airways of patients with COPD and will predict exacerbations? STUDY DESIGN AND METHODS: We applied a mass spectrometric panel of metabolomic biomarkers related to mucus hydration and inflammation to sputa from the multicenter Subpopulations and Intermediate Outcome Measures in COPD Study. Biomarkers elevated in sputa from patients with COPD were evaluated for relationships to measures of COPD disease severity and their ability to predict future exacerbations. RESULTS: Sputum supernatants from 980 patients were analyzed: 77 healthy nonsmokers, 341 smokers with preserved spirometry, and 562 patients with COPD (178 with Global Initiative on Chronic Obstructive Lung Disease [GOLD] stage 1 disease, 303 with GOLD stage 2 disease, and 81 with GOLD stage 3 disease) were analyzed. Biomarkers from multiple pathways were elevated in COPD and correlated with sputum neutrophil counts. Among the most significant analytes (false discovery rate, 0.1) were sialic acid, hypoxanthine, xanthine, methylthioadenosine, adenine, and glutathione. Sialic acid and hypoxanthine were associated strongly with measures of disease severity, and elevation of these biomarkers was associated with shorter time to exacerbation and improved prediction models of future exacerbations. INTERPRETATION: Biomarker evaluation implicated pathways involved in mucus hydration, adenosine metabolism, methionine salvage, and oxidative stress in COPD airway pathophysiologic characteristics. Therapies that target these pathways may be of benefit in COPD, and a simple model adding sputum-soluble phase biomarkers improves prediction of pulmonary exacerbations. TRIAL REGISTRY: ClinicalTrials.gov; No.: NCT01969344; URL: www. CLINICALTRIALS: gov.

Phenotypic characteristics of incident and chronic MRSA isolates in cystic fibrosis.

BACKGROUND: Chronic methicillin resistant Staphylococcus aureus (MRSA) in CF is associated with worse outcomes compared to early or intermittent infection. This observation could be related to adaptive bacterial changes such as biofilm formation or anaerobic growth. METHODS: MRSA isolates stored from incident and during chronic (>2 years) infection were included at two study sites. MRSA isolates were characterised by spa-typing, antimicrobial susceptibility testing, biofilm formation and haemolysis under aerobic and anaerobic culture conditions. RESULTS: Paired MRSA isolates from 49 patients were included. Mean age at incident infection was 9.7±1.2 years with mild to moderate lung disease (FEV1 74±4% predicted). Twenty-five subjects showed progression of disease/symptoms after onset of MRSA with significantly increased use of antibiotics. Most isolates belonged to t002 (38%) and t008 (36%) spa-types and 8 patients had a change in spa-type over time. Antimicrobial susceptibility testing showed few differences between incident and late isolates but significantly lower MIC under anaerobic vs. aerobic conditions for vancomycin, fusidic acid, rifampin but higher MIC for trimethoprim-sulfamethoxazole. Biofilm formation and haemolysis did not differ by stage of infection or disease course but both were lower under anaerobic conditions (biofilm p=0.018; haemolysis p=0.002) in multi-variate analyses that included study site, growth condition and stage of infection. CONCLUSIONS: Persistent MRSA infection is frequently associated with clinical decline. Anaerobic growth conditions, which occur in CF airways, affect the expression of virulence factors and antibiotic susceptibility of MRSA more than duration of infection.

Acute and durable effect of inhaled hypertonic saline on mucociliary clearance in adult asthma.

BACKGROUND: Impaired mucus clearance and airway mucus plugging have been shown to occur in moderate-severe asthma, especially during acute exacerbations. In cystic fibrosis, where airway mucus is dehydrated, it has been shown that inhaled hypertonic saline (HS) produces both acute and sustained enhancement of mucociliary clearance (MCC). The current study was designed to assess the acute and sustained effect of inhaled 7% HS on MCC in adult asthma. METHODS: Well-controlled, moderate-severe female asthmatic patients (n=8) were screened with a single test dose of albuterol (four puffs by metered-dose inhaler) followed by HS (7% sodium chloride, 4 mL using PARI LC Star nebuliser). Spirometry was measured pre-treatment and 5 and 30 min post-treatment for safety. MCC was measured using γ-scintigraphy on three separate visits: at baseline, during inhalation and 4 h after a single dose of HS. RESULTS: MCC was acutely enhanced during HS treatment; mean±sd clearance over 60 min of dynamic imaging (Ave60Clr) was 8.9±7.9% (baseline) versus 23.4±7.6% (acute HS) (p<0.005). However, this enhancement was not maintained over a 4-h period where post-HS treatment Ave60Clr was 9.3±8.2%. In this small cohort we found no decrements in lung function up to 30 min post-treatment (forced expiratory volume in 1 s 97.4±10.0% predicted pre-treatment and 98.9±10.7% predicted 30 min post-treatment). CONCLUSION: While MCC was rapidly enhanced during 7% HS treatment there was no effect on MCC at 4 h post-treatment. While these findings may not support aerosolised HS use for maintenance therapy, they do suggest a benefit of treating acute exacerbations in patients with moderate-severe asthma.

Airway mucin MUC5AC and MUC5B concentrations and the initiation and progression of chronic obstructive pulmonary disease: an analysis of the SPIROMICS cohort.

BACKGROUND: We previously described the contributions of increased total airway mucin concentrations to the pathogenesis and diagnosis of the chronic bronchitic component of chronic obstructive pulmonary disease (COPD). Here, we investigated the relative contribution of each of the major airway gel-forming mucins, MUC5AC and MUC5B, to the initiation, progression, and early diagnosis of airways disease in COPD. METHODS: SPIROMICS was a multicentre, observational study in patients aged 40-80 years recruited from six clinical sites and additional subsites in the USA. In this analysis, MUC5AC and MUC5B were quantitated by stable isotope-labelled mass spectrometry in induced sputum samples from healthy never-smokers, ever-smokers at risk for COPD, and ever-smokers with COPD. Participants were extensively characterised using results from questionnaires, such as the COPD assessment test (CAT) and St George's Respiratory Questionnaire; quantitative CT, such as residual volume/total lung capacity ratio (RV/TLC) and parametric response mapping-functional small airway disease (PRM-fSAD); and pulmonary function tests, such as FEV1, forced vital capacity (FVC), and forced expiratory flow, midexpiratory phase (FEF25-75%). Absolute concentrations of both MUC5AC and MUC5B were related to cross-sectional (baseline, initial visit) and 3-year follow-up longitudinal data, including lung function, small airways obstruction, prospective acute exacerbations, and smoking status as primary outcomes. This study is registered with ClinicalTrials.gov (NCT01969344). FINDINGS: This analysis included 331 participants (mean age 63 years [SEM 9·40]), of whom 40 were healthy never-smokers, 90 were at-risk ever-smokers, and 201 were ever-smokers with COPD. Increased MUC5AC concentrations were more reliably associated with manifestations of COPD than were MUC5B concentrations, including decreased FEV1 and FEF25-75%, and increased prospective exacerbation frequency, RV/TLC, PRM-fSAD, and COPD assessment scores. MUC5AC concentrations were more reactive to cigarette smoke exposure than were MUC5B concentrations. Longitudinal data from 3-year follow-up visits generated a multivariate-adjusted odds ratio for two or more exacerbations of 1·24 (95% CI 1·04-1·47, p=0·015) for individuals with high baseline MUC5AC concentration. Increased MUC5AC, but not MUC5B, concentration at baseline was a significant predictor of FEV1, FEV1/FVC, FEF25-75%, and CAT score decline during the 3-year follow-up. Moreover, current smokers in the at-risk group showed raised MUC5AC concentrations at initial visits and decreased lung function over 3 years. By contrast, former smokers in the at-risk group showed normal MUC5AC concentrations at the initial visit and preserved lung function over 3 years. INTERPRETATION: These data indicate that increased MUC5AC concentration in the airways might contribute to COPD initiation, progression, exacerbation risk, and overall pathogenesis. Compared with MUC5B, greater relative changes in MUC5AC concentrations were observed as a function of COPD severity, and MUC5AC concentration seems to be an objective biomarker to detect disease in at-risk and pre-COPD individuals. These data suggest that MUC5AC-producing pathways could be potential targets for future therapeutic strategies. Thus, MUC5AC could be a novel biomarker for COPD prognosis and for testing the efficacy of therapeutic agents. FUNDING: National Institutes of Health; National Heart, Lung, and Blood Institute.

Comparison of single breath hyperpolarized 129 Xe MRI with dynamic 19 F MRI in cystic fibrosis lung disease.

PURPOSE: To quantitatively compare dynamic 19 F and single breath hyperpolarized 129 Xe MRI for the detection of ventilation abnormalities in subjects with mild cystic fibrosis (CF) lung disease. METHODS: Ten participants with stable CF and a baseline FEV1 > 70% completed a single imaging session where dynamic 19 F and single breath 129 Xe lung ventilation images were acquired on a 3T MRI scanner. Ventilation defect percentages (VDP) values between 19 F early-breath, 19 F maximum-ventilation, 129 Xe low-resolution, and 129 Xe high-resolution images were compared. Dynamic 19 F images were used to determine gas wash-in/out rates in regions of ventilation congruency and mismatch between 129 Xe and 19 F. RESULTS: VDP values from high-resolution 129 Xe images were greater than from low-resolution images (P = .001), although these values were significantly correlated (r = 0.68, P = .03). Early-breath 19 F VDP and max-vent 19 F VDP also showed significant correlation (r = 0.75, P = .012), with early-breath 19 F VDP values being significantly greater (P < .001). No correlation in VDP values were detected between either 19 F method or high-res 129 Xe images. In addition, the location and volume of ventilation defects were often different when comparing 129 Xe and 19 F images from the same subject. Areas of ventilation congruence displayed the expected ventilation kinetics, while areas of ventilation mismatch displayed abnormally slow gas wash-in and wash-out. CONCLUSION: In CF subjects, ventilation abnormalities are identified by both 19 F and HP 129 Xe imaging. However, these ventilation abnormalities are not entirely congruent. 19 F and HP 129 Xe imaging provide complementary information that enable differentiation of normally ventilated, slowly ventilated, and non-ventilated regions in the lungs.

Effect of hypertonic saline on mucociliary clearance and clinical outcomes in chronic bronchitis.

BACKGROUND: Mucus dehydration and impaired mucus clearance are common features of cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). In CF, inhaled hypertonic saline (HS) improves lung function and produces sustained increases in mucociliary clearance (MCC). We hypothesised that administration of HS (7% NaCl) twice daily for 2 weeks would improve clinical outcomes and produce sustained increases in MCC in COPD subjects with a chronic bronchitis (CB) phenotype. METHODS: Twenty-two CB subjects completed a double-blinded, crossover study comparing inhaled HS to a hypotonic control solution (0.12% saline) administered via nebuliser twice daily for 2 weeks. Treatment order was randomised. During each treatment period, symptoms and spirometry were measured. MCC was measured at baseline, shortly after initial study agent administration, and approximately 12 h after the final dose. RESULTS: HS was safe and well tolerated but overall produced no significant improvements in spirometry or patient-reported outcomes. CB subjects had slower baseline MCC than healthy subjects. The MCC rates over 60 min (Ave60Clr) in CB subjects following 2 weeks of HS were not different from 0.12% saline but were slower than baseline (Ave60Clr was 9.1±6.3% at baseline versus 5.3±6.9% after HS; p<0.05). Subgroup analyses determined that subjects with residual baseline central lung clearance (14 subjects) had improved spirometry and symptoms following treatment with HS, but not 0.12% saline, treatment. CONCLUSIONS: Inhaled HS appeared to be safe in a general CB population. A specific phenotypic subgroup may benefit from HS but requires additional study.

A four week trial of hypertonic saline in children with mild cystic fibrosis lung disease: Effect on mucociliary clearance and clinical outcomes.

BACKGROUND: Hypertonic saline (HS) is commonly prescribed for children with cystic fibrosis (CF) despite the absence of strong data indicating clinical efficacy in a population with mild lung disease. We hypothesized that HS treatment would result in a sustained improvement in mucociliary clearance (MCC) in children with CF who had minimal lung disease, thus providing evidence for a biologically relevant effect that also may be associated with clinical improvements. METHODS: We performed a randomized, placebo controlled, double blind study of 6% versus 0.12% sodium chloride, delivered three-times daily with an eFlow nebulizer for 4 weeks. MCC was measured using gamma scintigraphy at baseline, 2-hours after the first study treatment, and ~12-hours after the final dose (at day 28). Spirometry, respiratory symptoms (CFQ-R), and safety were also assessed. RESULTS: Study treatments were generally well tolerated and safe. HS (6% sodium chloride) resulted in a significant, sustained improvement from baseline in whole lung clearance after 4 weeks of therapy (p = 0.014), despite absence of a prolonged single-dose effect after the initial dose. This sustained change (12 hrs after prior dose) was significantly greater when compared to placebo (0.12% sodium chloride) treatment (p = 0.016). Improvements in spirometry with HS did not reach statistical significance but correlated with MCC changes. CONCLUSIONS: The observed sustained improvement in MCC with HS suggests that this treatment may yield health benefits, even in relatively mildly affected children with CF. Highlighting this physiologic finding is important due to the lack of meaningful, validated endpoints in this population.