Restoring Cystic Fibrosis Transmembrane Conductance Regulator Function Reduces Airway Bacteria and Inflammation in People with Cystic Fibrosis and Chronic Lung Infections.

RATIONALE: Previous work indicates that ivacaftor improves cystic fibrosis transmembrane conductance regulator (CFTR) activity and lung function in people with cystic fibrosis and G551D-CFTR mutations but does not reduce density of bacteria or markers of inflammation in the airway. These findings raise the possibility that infection and inflammation may progress independently of CFTR activity once cystic fibrosis lung disease is established. OBJECTIVES: To better understand the relationship between CFTR activity, airway microbiology and inflammation, and lung function in subjects with cystic fibrosis and chronic airway infections. METHODS: We studied 12 subjects with G551D-CFTR mutations and chronic airway infections before and after ivacaftor. We measured lung function, sputum bacterial content, and inflammation, and obtained chest computed tomography scans. MEASUREMENTS AND MAIN RESULTS: Ivacaftor produced rapid decreases in sputum Pseudomonas aeruginosa density that began within 48 hours and continued in the first year of treatment. However, no subject eradicated their infecting P. aeruginosa strain, and after the first year P. aeruginosa densities rebounded. Sputum total bacterial concentrations also decreased, but less than P. aeruginosa. Sputum inflammatory measures decreased significantly in the first week of treatment and continued to decline over 2 years. Computed tomography scans obtained before and 1 year after ivacaftor treatment revealed that ivacaftor decreased airway mucous plugging. CONCLUSIONS: Ivacaftor caused marked reductions in sputum P. aeruginosa density and airway inflammation and produced modest improvements in radiographic lung disease in subjects with G551D-CFTR mutations. However, P. aeruginosa airway infection persisted. Thus, measures that control infection may be required to realize the full benefits of CFTR-targeting treatments.

Relationship between pulmonary hyperinflation and dyspnoea severity during acute exacerbations of cystic fibrosis.

BACKGROUND AND OBJECTIVE: Acute exacerbations of cystic fibrosis (CF) occur frequently throughout the course of the disease. Dyspnoea is the most common and distressing symptom experienced by patients during these episodes. We tested the hypothesis that pulmonary hyperinflation is an important determinant of dyspnoea severity during acute exacerbations. METHODS: We studied patients during an acute exacerbation of CF. Lung volumes, spirometry and dyspnoea scores were measured at Day 0, Day 7, at the end of treatment (EOT) and 14 days following the EOT. RESULTS: At the start of treatment, mean residual volume (RV)/total lung capacity (TLC) was 54.9%, which decreased significantly with treatment, as did vital capacity (VC), inspiratory capacity (IC) and dyspnoea scores. IC was the only independent predictor of dyspnoea severity. CONCLUSION: Our study demonstrates significant improvements in hyperinflation, spirometry and dyspnoea scores with treatment of acute exacerbations of CF. Hyperinflation, rather than airflow limitation, may contribute towards the increased dyspnoea during exacerbations.

Macrophage migration inhibitory factor enzymatic activity, lung inflammation, and cystic fibrosis.

RATIONALE: Macrophage migration inhibitory factor (MIF) is a proinflammatory mediator with unique tautomerase enzymatic activity; the precise function has not been clearly defined. We previously demonstrated that individual patients with cystic fibrosis (CF) who are genetically predisposed to be high MIF producers develop accelerated end-organ injury. OBJECTIVES: To characterize the effects of the MIF-CATT polymorphism in patients with CF ex vivo. To investigate the role of MIF's tautomerase activity in a murine model of Pseudomonas aeruginosa infection. METHODS: MIF and tumor necrosis factor (TNF)-α protein levels were assessed in plasma or peripheral blood mononuclear cell (PBMC) supernatants by ELISA. A murine pulmonary model of chronic Pseudomonas infection was used in MIF wild-type mice (mif(+/+)) and in tautomerase-null, MIF gene knockin mice (mif (P1G/P1G)). MEASUREMENTS AND MAIN RESULTS: MIF protein was measured in plasma and PBMCs from 5- and 6-CATT patients with CF; LPS-induced TNF-α production from PBMCs was also assessed. The effect of a specific inhibitor of MIF-tautomerase activity, ISO-1, was investigated in PBMCs. In the murine infection model, total weight loss, differential cell counts, bacterial load, and intraacinar airspace/tissue volume were measured. MIF and TNF-α levels were increased in 6-CATT compared with 5-CATT patients with CF. LPS-induced TNF-α production from PBMCs was attenuated in the presence of ISO-1. In a murine model of Pseudomonas infection, significantly less pulmonary inflammation and bacterial load was observed in mif(P1G/P1G) compared with mif(+/+) mice. CONCLUSIONS: MIF-tautomerase activity may provide a novel therapeutic target in patients with chronic inflammatory diseases such as CF, particularly those patients who are genetically predisposed to produce increased levels of this cytokine.

High-resolution CT of nontuberculous mycobacterium infection in adult CF patients: diagnostic accuracy.

OBJECTIVES: To determine the diagnostic accuracy of high-resolution computed tomography (HRCT) for the detection of nontuberculous mycobacterium infection (NTM) in adult cystic fibrosis (CF) patients. METHODS: Twenty-seven CF patients with sputum-culture-proven NTM (NTM+) underwent HRCT. An age, gender and spirometrically matched group of 27 CF patients without NTM (NTM-) was included as controls. Images were randomly and blindly analysed by two readers in consensus and scored using a modified Bhalla scoring system. RESULTS: Significant differences were seen between NTM (+) and NTM (-) patients in the severity of the bronchiectasis subscore [45 % (1.8/4) vs. 35 % (1.4/4), P = 0.029], collapse/consolidation subscore [33 % (1.3/3 vs. 15 % (0.6/3)], tree-in-bud/centrilobular nodules subscore [43 % (1.7/3) vs. 25 % (1.0/3), P = 0.002] and the total CT score [56 % (18.4/33) vs. 46 % (15.2/33), P = 0.002]. Binary logistic regression revealed BMI, peribronchial thickening, collapse/consolidation and tree-in-bud/centrilobular nodules to be predictors of NTM status (R(2 )= 0.43). Receiver-operator curve analysis of the regression model showed an area under the curve of 0.89, P < 0.0001. CONCLUSION: In adults with CF, seven or more bronchopulmonary segments showing tree-in-bud/centrilobular nodules on HRCT is highly suggestive of NTM colonisation. KEY POINTS: Lung function declines rapidly in cystic fibrosis patients with nontuberculous mycobacterium infection. High-resolution computed tomography can help identify nontuberculous mycobacterium in CF patients. Extensive collapse/consolidation and tree-in-bud/centrilobular nodules are predictive of NTM infection. Multiple bronchopulmonary segments showing tree-in-bud/centrilobular nodules strongly suggest nontuberculous mycobacterium infection.

Duration of intravenous antibiotic treatment for acute exacerbations of cystic fibrosis: A systematic review.

BACKGROUND: Acute exacerbations of Cystic Fibrosis (AECF) are associated with significant morbidity. Recommendations are to treat for 2-3 weeks despite limited data. Spirometry is a measure of clinical response yet appears to plateau at 7-10 days. While durations <9 days have been associated with poorer outcomes, a duration of 10 days may be as effective as 14 days, potentially conferring advantages in terms of cost and adverse events. A 2019 Cochrane review by Abbott et al. did not identify any randomised controlled trials (RCT) comparing durations of treatment. Utilising data from non-randomised studies (NRS), we report a systematic review of intravenous antibiotic treatment, exploring changes in FEV1 (Forced Expiratory Volume in 1 second), CRP (C-reactive protein) and peripheral WBC (white blood cell) count in studies with different treatment durations. STUDY DESIGN AND METHODS: Systematic review of published literature following a search of MEDLINE, Embase, CINAHL and the Cochrane Clinical Trials register. Guidelines from the Preferred Reporting items for Systematic reviews and Meta-Analysis (PRISMA) and reporting Meta-analysis of Observational studies (MOOSE) statement were followed. RESULTS: No randomised controlled trials were identified that specifically examined duration of treatment during AECF. This study included all relevant RCTs and also NRS, grouping according to study characteristics, such as length of treatment, location, year, and also characteristics of the patient population. 52 studies, comprising 79 subgroups, and 1,597 patients, were identified. Mean change (95%CI) in ppFEV1 was 10.13 (9.21-11.05). There was no significant difference in change in ppFEV1 for studies treating for 10-12 days; 8.85 (7.47-10.23), vs 13-15 days; 10.68 (9.53-11.82). Similar changes in CRP and WBC were seen irrespective of treatment duration. CONCLUSION: This systematic review provides evidence that shorter durations of treatment may be associated with similar changes in FEV1, CRP and WBC compared with longer durations.

Acute Pulmonary Exacerbation Phenotypes in Patients with Cystic Fibrosis.

Rationale: The etiology of cystic fibrosis (CF) pulmonary exacerbations (PEx) is likely multifactorial with viral, bacterial, and non-infectious pathways contributing. Objectives: To determine whether viral infection status and CRP (C-reactive protein) can classify subphenotypes of PEx that differ in outcomes and biomarker profiles. Methods: Patients were recruited at time of admission for a PEx. Nasal swabs and sputum samples were collected and processed using the respiratory panel of the FilmArray multiplex polymerase chain reaction (PCR). Serum and plasma biomarkers were measured. PEx were classified using serum CRP and viral PCR: "pauci-inflammatory" if CRP < 5 mg/L, "non-viral with systemic inflammation" if CRP ⩾ 5 mg/L and no viral infection detected by PCR and "viral with systemic inflammation" if CRP ⩾ 5 mg/L and viral infection detected by PCR. Results: Discovery cohort (n = 59) subphenotype frequencies were 1) pauci-inflammatory (37%); 2) non-viral with systemic inflammation (41%); and 3) viral with systemic inflammation (22%). Immunoglobulin G, immunoglobulin M, interleukin-10, interleukin-13, serum calprotectin, and CRP levels differed across phenotypes. Reduction from baseline in forced expiratory volume in 1 second as percent predicted (FEV1pp) at onset of exacerbation differed between non-viral with systemic inflammation and viral with systemic inflammation (-6.73 ± 1.78 vs. -13.5 ± 2.32%; P = 0.025). Non-viral with systemic inflammation PEx had a trend toward longer duration of intravenous antibiotics versus pauci-inflammation (18.1 ± 1.17 vs. 14.8 ± 1.19 days, P = 0.057). There were no differences in percent with lung function recovery to <10% of baseline FEV1pp. Similar results were seen in local and external validation cohorts comparing a pauci-inflammatory to viral/non-viral inflammatory exacerbation phenotypes. Conclusions: Subphenotypes of CF PEx exist with differences in biomarker profile, clinical presentation, and outcomes.

Outcome in cystic fibrosis liver disease.

OBJECTIVES: Evidence suggests that cystic fibrosis liver disease (CFLD) does not affect mortality or morbidity in patients with cystic fibrosis (CF). The importance of gender and age in outcome in CF makes selection of an appropriate comparison group central to the interpretation of any differences in mortality and morbidity in patients with CFLD. METHODS: This is a 7-year follow-up of 42 children with CFLD and their age- and sex-matched controls. Participants were reviewed clinically, biochemically, and radiologically at follow-up. RESULTS: Overall, 85% (72 of 84) of the original cohort were included, 36 CFLD participants and 36 CF controls. There was no significant difference in the number of deaths/transplants between groups (7 of 36 (19.4%) CFLD participants, 3 of 36 (8.3%) CF controls). There was a tendency for participants with CFLD to die younger than their respective CF controls. There was no difference in height, weight, body mass index, or pulmonary function between the groups. Nutritional parameters (sum skinfold thickness 31.6 vs. 42.3, P=0.03; mean upper arm fat area 15.08 vs. 10.59, P=0.001; Shwachman score 43.7 vs. 32.1, P=0.001) were worse among CFLD participants than among CF controls. Cystic fibrosis-related diabetes was more common in CFLD participants (11 of 27 (40.7%) vs. 5 of 33 (15.2%), P=0.02). Eight children (22.2%) with evidence of CFLD at baseline had no clinical evidence of liver disease as adults. CONCLUSIONS: Patients with CFLD have a more severe CF phenotype than do CF patients without liver disease. However, a subgroup of children with CFLD will not manifest clinically significant liver disease as adults.

A clinical investigation into the ability of subjects with lung disease to provide breath specimens using the EvidenzerIRL evidential breath analyser in alcohol intoxicant driving in criminal justice evidence.

The EvidenzerIRL instrument has been in use as an evidential breath analyser in the application of drink driving laws in the Republic of Ireland since 2011. The result of the analysis is used as evidence in prosecutions before the Courts in per se offences of driving under the influence of alcohol as distinct from screening results at the roadside. This study aims to assist doctors, lawyers and judges in assessing drivers' failure to provide valid evidential breath specimens. Since the introduction of the EvidenzerIRL, approximately 10% of evidential breath tests annually result in failure or refusal to provide a successful breath specimen, this is an offence under Irish road traffic laws. The presence of lung disease has been given as a reason for the driver failing to provide evidential breath specimens. The aim of this study is to assess the ability of subjects with lung disease to provide breath specimens using the EvidenzerIRL. Pulmonary function tests (PFT) were carried out on volunteers from outpatients of the pulmonary laboratory in St Vincent's University Hospital, Dublin (n = 58) and a control group with no underlying lung disease (n = 19). After the PFTs all volunteers were asked to provide breath specimens using the EvidenzerIRL. Fourteen (24%) out of 58 lung disease volunteers failed to provide a breath specimen, no one from the control group was unsuccessful. Thirteen females and one male volunteer could not successfully provide. Female volunteers were more likely to fail to provide than male volunteers. A significant difference was found between the median age of successful (62.2 years) and unsuccessful (69.2 years) lung disease volunteers. Only one PFT, percentage predicted of Forced Expiratory Volume in 1 second (FEV1), had a significant difference between the mean of successful (86.6%) and unsuccessful (66.5%) lung disease volunteers. A subject with lung disease was more likely to be successful than unsuccessful. Drivers' effort and operators' guidance through the process were found to be crucial parts to a successful outcome.

EDNRA variants associate with smooth muscle mRNA levels, cell proliferation rates, and cystic fibrosis pulmonary disease severity.

Airway inflammation and pulmonary disease are heterogeneous phenotypes in cystic fibrosis (CF) patients, even among patients with the same cystic fibrosis transmembrane conductance regulator (CFTR) genotype. Endothelin, a proinflammatory peptide and smooth muscle agonist, is increased in CF airways, potentially contributing to the pulmonary phenotype. Four cohorts of CF patients were screened for variants in endothelin pathway genes to determine whether any of these variants associated with pulmonary function. An initial cohort of 808 CF patients homozygous for the common CF mutation, DeltaF508, showed significant association for polymorphisms in the endothelin receptor A gene, EDNRA (P = 0.04), but not in the related endothelin genes (EDN1, EDN2, EDN3, or EDNRB) or NOS1, NOS2A, or NOS3. Variants within EDNRA were examined in three additional cohorts of CF patients, 238 patients from Seattle, WA, 303 from Ireland and the U.K., and 228 from Cleveland, OH, for a total of 1,577 CF patients. The three additional groups each demonstrated a significant association between EDNRA 3'-untranslated region (UTR) variant rs5335 and pulmonary function (P = 0.002). At the molecular level, single nucleotide primer extension assays suggest that the effect of the variants is quantitative. EDNRA mRNA levels from cultured primary tracheal smooth muscle cells are greater for the allele that appears to be deleterious to lung function than for the protective allele, suggesting a mechanism by which increased receptor function is harmful to the CF airway. Finally, cell proliferation studies using human airway smooth muscle cells demonstrated that cells homozygous for the deleterious allele proliferate at a faster rate than those homozygous for the protective allele.

Longitudinal Trends in Real-World Outcomes after Initiation of Ivacaftor. A Cohort Study from the Cystic Fibrosis Registry of Ireland.

RATIONALE: Patient registries have the potential to collect and analyze high-quality postauthorization data on new medicines. OBJECTIVES: We used cystic fibrosis (CF) registry data to assess outcomes after the initiation of ivacaftor, a CF transmembrane conductance regulator (CFTR) potentiator approved for the treatment of CF with a defective gating CFTR mutation. METHODS: Longitudinal trends were examined using mixed-effects regression analysis in 80 ivacaftor-treated patients with CF aged 6 to 56 years registered with the CF Registry of Ireland with at least 36 months of before and after commencement data. The effects of ivacaftor treatment on forced expiratory volume in 1 second (FEV1) % predicted, body mass index (BMI), hospitalization for pulmonary exacerbation, and oral and intravenous antibiotic use were assessed. RESULTS: In the 36 months after ivacaftor initiation, FEV1% predicted improved by 2.26% per annum (95% confidence interval [CI], 0.2 to 4.3) for patients aged younger than 12 years, remained unchanged for 12- to younger than 18-year-olds (95% CI, -1.9 to 2.9), and declined in adults by 1.74% per annum (95% CI, -3.1 to -0.4). BMI in adults increased 0.28 kg/m2 per annum (95% CI, 0.03 to 0.5), and there was no significant change in BMI z-score in children (95% CI, -0.01 to 0.1). In the year after ivacaftor initiation, intravenous antibiotic treatment reduced by 46% (95% CI, -62.5% to -23.3%, oral antibiotic treatment reduced by 49% (95% CI, -61.1% to -32.1%), and there was no significant reduction in hospitalization (95% CI, -59.2% to 9.7%). CONCLUSIONS: In this study of real-world CF registry data, clinical outcomes improved and healthcare resource utilization decreased after commencing ivacaftor.

Evaluation of in vitro virulence characteristics of the genus Pandoraea in lung epithelial cells.

Pandoraea species are emerging opportunistic pathogens capable of causing chronic lung infections in cystic fibrosis patients. This study examined the interactions of 17 Pandoraea isolates from the five identified species (Pandoraea apista, Pandoraea norimbergensis, Pandoraea pulmonicula, Pandoraea sputorum and Pandoraea pnomenusa) plus two Pandoraea genomospecies isolates with lung epithelial cells and their ability to form biofilms in vitro. Only three isolates showed an ability to invade A549 lung epithelial cells, and only one isolate was able to form biofilms. In contrast, all isolates triggered a pronounced pro-inflammatory response, with elevation of both interleukin (IL)-6 (two- to 19-fold) and IL-8 (10- to 50-fold) above that observed for a control strain of Escherichia coli. This property is likely to be a major factor in the pathogenesis of the genus.

Bone mineral density in cystic fibrosis: benefit of exercise capacity.

The aim of this study was to evaluate the association between bone mineral density (BMD) and objective maximal exercise measurements in adults with cystic fibrosis (CF). Twenty-five CF patients (19 males, 6 females, mean age 25.5 yr, range: 17-52) underwent BMD assessment and maximal-cycle ergometer exercise testing. We examined the relationship between gas exchange (% peak-predicted O(2) uptake, CO(2) output, O(2) saturation), exercise performance (maximum power, exercise duration), and respiratory mechanics (tidal volume, rate) with lumbar spine and total proximal femur BMD. The strongest clinical correlate with BMD was forced expiratory volume at 1s (lumbar spine Z-score, r=0.36; total proximal femur Z-score, r=0.68, p<0.01). The strongest exercise correlate was % peak-predicted O(2) uptake (lumbar spine Z-score, r=0.44, p<0.01; total proximal femur Z-score, r=0.59, p<0.01). There was a closer association between exercise parameters and total proximal femur BMD (r=0.43-0.60) than with lumbar spine BMD (r=0.04-0.45). Multiple regression analysis revealed VO(2) to be the strongest independent predictor of BMD (R(2)=0.86, p<0.001) followed by petCO(2) and body mass index (R(2)=0.7 and 0.5, respectively, p<0.01). Exercise appears to influence total proximal femur BMD more than lumbar spine BMD in CF. Exercise rehabilitation programs focusing on peripheral strength training may benefit those CF patients with low total proximal femur BMD.

The repeatability of submaximal endurance exercise testing in cystic fibrosis.

Submaximal endurance cycle ergometer exercise tests are used to measure the efficacy of an exercise intervention, but the repeatability of these tests in patients with cystic fibrosis (CF) has not been established. The purpose of this study was to examine the repeatability of submaximal endurance testing in stable CF. Fifteen adults with CF underwent two submaximal endurance tests carried out over a 7-day period. A subset of six subjects returned 28 days later for a third submaximal endurance test. Workload was set at 80% of maximum workload and exercise was performed to exhaustion. Oxygen consumption, minute ventilation, tidal volume, carbon dioxide output, respiratory rate, heart rate, and oxygen saturation were measured at rest, at end exercise and at four matched times during the submaximal endurance tests (20, 40, 60, and 80% of exercise duration calculated from the first endurance test). Submaximal endurance test time was highly repeatable with no significant learning effect identified on multiple testing. Submaximal endurance exercise time demonstrated a variability of 5.7% which is consistent with high levels of repeatability. Metabolic, ventilatory and cardiac variables were all also highly reproducible between test days. Submaximal endurance testing is repeatable in stable CF, confirming that submaximal endurance tests are a reliable tool for assessment of therapeutic benefit in patients with CF.

Pulmonary abnormalities on high-resolution CT demonstrate more rapid decline than FEV1 in adults with cystic fibrosis.

BACKGROUND: FEV1 may remain stable while high-resolution CT (HRCT) appearances deteriorate in children with cystic fibrosis (CF). However, spirometry results commonly decline in older age groups. OBJECTIVES: To compare the rate of decline in HRCT abnormalities and spirometry results over time in an adult cohort with CF. METHODS: The HRCT scans of 39 consecutive patients (19 males and 20 females; mean age, 22 years; range, 16 to 48 years) with two HRCT scans > 18 months apart were randomly and blindly scored using a modified Bhalla scoring system by two independent chest radiologists. Age, body mass index, spirometry, and sputum cultures were recorded at the time of both HRCTs. Rates of change in clinical parameters and HRCT abnormalities were calculated and compared using repeated-measures analysis of variance. RESULTS: Mean FEV1 declined at a rate of - 2.3% per year, while mean HRCT total score declined at a rate of -2.7% per year. Several individual HRCT abnormalities as well as HRCT total scores declined significantly faster than FEV1 (p < 0.001). Six patients showed stable spirometry results but worsening HRCT scores. Mucus plugging and extent of bronchiectasis deteriorated at a more rapid rate in the group with mildly impaired lung function. Air trapping, collapse/consolidation, peribronchial thickening, severity of bronchiectasis, and generations of bronchial divisions involved deteriorated at a more rapid rate in the group with moderate-to-severely impaired lung function. CONCLUSIONS: Adult CF patients have more rapid rates of decline in HRCT abnormalities than in spirometry results. Individual HRCT abnormalities decline at different rates depending on the degree of lung function impairment.