A common polymorphism in the Intelectin-1 gene influences mucus plugging in severe asthma

By incompletely understood mechanisms, type 2 (T2) inflammation present in the airways of severe asthmatics drives the formation of pathologic mucus which leads to airway mucus plugging. Here we investigate the molecular role and clinical significance of intelectin-1 (ITLN-1) in the development of pathologic airway mucus in asthma. Through analyses of human airway epithelial cells we find that ITLN1 gene expression is highly induced by interleukin-13 (IL-13) in a subset of metaplastic MUC5AC+ mucus secretory cells, and that ITLN-1 protein is a secreted component of IL-13-induced mucus. Additionally, we find ITLN-1 protein binds the C-terminus of the MUC5AC mucin and that its deletion in airway epithelial cells partially reverses IL-13-induced mucostasis. Through analysis of nasal airway epithelial brushings, we find that ITLN1 is highly expressed in T2-high asthmatics, when compared to T2-low children. Furthermore, we demonstrate that both ITLN-1 gene expression and protein levels are significantly reduced by a common genetic variant that is associated with protection from the formation of mucus plugs in T2-high asthma. This work identifies an important biomarker and targetable pathways for the treatment of mucus obstruction in asthma.

Elevated serum IL-8 levels in ataxia telangiectasia

Serum interleukin (IL)-8 levels were measured in 50 patients with ataxia telangiectasia (A-T) and 22 without A-T. In a cross-sectional study, the geometric mean of IL-8 level was significantly higher in the patients with A-T (P <.0001). Elevated serum IL-8 levels in patients with A-T suggest that systemic inflammation may contribute to the disease phenotype.

NHLBI training workshop report: The vanishing pediatric pulmonary investigator and recommendations for recovery

The adequacy of the pipeline of advanced pulmonary fellows to supply appropriately trained and committed researchers to enter academic careers was the major topic of a recently held National Heart Lung and Blood Institute NHLBI Workshop: Respiratory Medicine-Related Research Training for Adult and Pediatric Fellows. The special challenges and opportunities for the academic pediatric pulmonary trainee were discussed as part of this workshop and are discussed as a companion paper to the report by the full workshop. Surveys were conducted of pediatric chairs of academic departments and pediatric pulmonary training directors in the United States to examine the current status and opportunities for the pediatric pulmonary trainee. Strategies for recruitment and retention of talented young trainees and junior faculty are proposed.

NHLBI training workshop report: the vanishing pediatric pulmonary investigator and recommendations for recovery

The adequacy of the pipeline of advanced pulmonary fellows to supply appropriately trained and committed researchers to enter academic careers was the major topic of a recently held National Heart Lung and Blood Institute NHLBI Workshop: Respiratory Medicine-Related Research Training for Adult and Pediatric Fellows. The special challenges and opportunities for the academic pediatric pulmonary trainee were discussed as part of this workshop and are presented as a companion article to the report by the full workshop. Surveys were conducted of pediatric chairs of academic departments and pediatric pulmonary training directors in the United States to examine the current status and opportunities for the pediatric pulmonary trainee. Strategies for recruitment and retention of talented young trainees and junior faculty are proposed.

Pulmonary function in adolescents with ataxia telangiectasia

INTRODUCTION

Pulmonary complications are common in adolescents with ataxia telangiectasia (A-T), however objective measurements of lung function may be difficult to obtain because of underlying bulbar weakness, tremors, and difficulty coordinating voluntary respiratory maneuvers. To increase the reliability of pulmonary testing, minor adjustments were made to stabilize the head and to minimize leaks in the system. Fifteen A-T adolescents completed lung volume measurements by helium dilution. To assess for reproducibility of spirometry testing, 10 A-T adolescents performed spirometry on three separate occasions.

RESULTS

Total lung capacity (TLC) was normal or just mildly decreased in 12/15 adolescents tested. TLC correlated positively with functional residual capacity (FRC), a measurement independent of patient effort (R2=0.71). The majority of individuals had residual volumes (RV) greater than 120% predicted (10/15) and slow vital capacities (VC) less than 70% predicted (9/15). By spirometry, force vital capacity (FVC) and forced expiratory volume in 1 sec (FEV1) values were reproducible in the 10 individuals who underwent testing on three separate occasions (R=0.97 and 0.96 respectively). Seven of the 10 adolescents had FEV1/FVC ratios>90%.

CONCLUSION

Lung volume measurements from A-T adolescents revealed near normal TLC values with increased RV and decreased VC values. These findings indicate a decreased ability to expire to residual volume rather then a restrictive defect. Spirometry was also found to be reproducible in A-T adolescents suggesting that spirometry testing may be useful for tracking changes in pulmonary function over time in this population.

Duration of treatment effect after tobramycin solution for inhalation in young children with cystic fibrosis

RATIONALE

Among young children with cystic fibrosis (CF), Pseudomonas aeruginosa (Pa) airway infection is associated with increased morbidity and mortality. Early intervention strategies include tobramycin solution for inhalation (TSI), which can eradicate lower airway Pa from cultures obtained at the end of 28 days of treatment in young children.

METHODS

We conducted an open label, sequential cohort study of TSI in young children with CF to investigate duration of antimicrobial treatment effect. The primary outcome was lower airway Pa eradication per bronchoalveolar lavage (BAL) fluid culture. Sequential treatment cohorts varied by duration of treatment (28 or 56 days) and timing of follow-up BAL (at Days 56, 84, or 112). Subjects (N = 36) were treated with TSI, 300 mg twice daily, for 28 days or 56 days per cohort assignment.

RESULTS

Among 31 evaluable subjects, culture based, lower airway Pa eradication was observed in the majority of subjects for up to 1-3 months following TSI treatment: 75% in Cohort 28/56 (days of treatment/day of follow-up BAL), 63% in Cohort 28/84, 82% in Cohort 56/112, and 75% in Cohort 28/112. Non-mucoid Pa at baseline and/or exotoxin A seronegativity were associated with higher rates of eradication. There was a less pronounced effect of TSI treatment on Pa eradication from oropharyngeal cultures in all cohorts. TSI treatment was associated with reduced neutrophilic airway inflammation and was not related to any serious adverse events.

CONCLUSION

TSI monotherapy is safe and can eradicate lower airway Pa for up to 3 months after treatment in young children with CF.

Randomized, double-blind, placebo-controlled, dose-escalating study of aerosolized interferon gamma-1b in patients with mild to moderate cystic fibrosis lung disease

Interferon gamma-1b (IFN-gamma1b) is a pleiotropic cytokine with immunomodulatory activities that could decrease bacterial burden, inflammation, and obstruction in patients with CF. Patients with CF (> or =12 years old, FEV1 > or =40% predicted) were randomly assigned to sequential dose cohorts inhaling 500 microg IFN-gamma1b, 1,000 microg IFN-gamma1b, or placebo by Respirgard II nebulizer thrice weekly for 12 weeks. Sputum bacterial density and spirometry were measured. Safety, antibiotic use, hospitalization, and sputum neutrophils, elastase, DNA, IL-8, and myeloperoxidase were also evaluated. Sixty-six patients (mean age, 24 years, with mean baseline FEV1 of 74 +/- 20 (SD) percent predicted) were studied. One patient had bronchospasm after the first dose of IFN-gamma1b; the overall withdrawal rate was 15% (5 in the placebo group, 2 in the 500-microg IFN-gamma1b group, and 3 in the 1,000 microg IFN-gamma1b group). The 500-microg IFN-gamma1b dose was well-tolerated, but the 1,000-mug dose cohort, who had a higher baseline bacterial density than placebo patients (mean difference, 1.2 log(10) CFU/g sputum, 95% confidence interval (CI), 0.1,2.8, P=0.04), had 24% more hospitalizations for exacerbation than placebo patients (95% CI, 2,45%, P=0.05). There was a 0.12-l difference between the 500-microg IFN-gamma1b and placebo groups with respect to the 12-week change in FEV1 (active group minus placebo group, 95% CI, -0.03,0.26, P=0.11), as compared to a 0.01-l difference between the 1,000-microg IFN-gamma1b and placebo groups (95% CI, -0.16,0.17, P=0.96). No effects of IFN-gamma1b were seen in sputum bacterial density or inflammatory biomarkers at 12 weeks. Aerosolized IFN-gamma1b did not improve pulmonary function, reduce sputum bacterial density, or affect inflammatory sputum markers in patients with mild-moderate lung disease.

A multicenter study of the effect of solution temperature on nasal potential difference measurements

BACKGROUND

Nasal potential difference (PD) measurement quantifies the abnormal sodium and chloride transport that is characteristic of cystic fibrosis (CF) and has gained acceptance as both a diagnostic tool and outcome measure for new CF therapies. Because small changes in nasal PD-measured chloride transport are often an important component in evaluating new CF therapies, techniques to maximize sensitivity and reproducibility are essential.

STUDY OBJECTIVE

To determine if administration of warmed nasal PD solutions (37 degrees C), instead of room temperature solutions (22 degrees C), results in significant increase in nasal PD-measured transepithelial chloride transport.

DESIGN

Multicenter, prospective, cross-over trial of repeated measurements of nasal PD at 22 degrees C and 37 degrees C.

RESULTS

Thirty-two healthy volunteers completed the study (four centers, each with 8 subjects). For 22 degrees C vs 37 degrees C, baseline (+/- SD) nasal PD (- 19.3 +/- 6.9 millivolts [mV] vs - 18.8 +/- 7.7 mV, p = 0.76), amiloride-sensitive PD (Delta PD, 10.4 +/- 5.6 mV vs 11.0 +/- 6.1 mV, p = 0.60), and low chloride response (Delta PD, - 10.0 +/- 8.0 mV vs - 8.0 +/- 7.1 mV, p = 0.13) were not statistically significantly affected by warming of solutions. Warming solutions to 37 degrees C dramatically increased the chloride transport response to isoproterenol (Delta PD, - 6.9 +/- 6.4 mV vs - 13.3 +/- 8.8 mV, p < 0.01) and the combined total response to low chloride and isoproterenol (Delta PD, - 16.9 +/- 9.5 mV vs - 21.3 +/- 11.9 mV, p = 0.01). The average increases observed with warming in isoproterenol and combined total responses were - 6.4 mV (95% confidence interval [CI], - 8.5 to - 4.3) and - 4.4 mV (95% CI, - 7.6 to - 1.1), respectively.

CONCLUSIONS

Performing nasal PD studies with solutions at 37 degrees C instead of 22 degrees C increases the observed total chloride response by approximately 25% and the isoproterenol-dependent chloride response by approximately 95%. The Cystic Fibrosis Foundation Therapeutics Development Network now recommends warming of solutions as a standard procedure for nasal PD protocols. Utilization of warmed solutions will standardize nasal PD techniques across centers and potentially increase the ability to identify therapies that result in small incremental improvements in CF transmembrane conductance regulator function.

Safety of aerosolized INS 365 in patients with mild to moderate cystic fibrosis: results of a phase I multi-center study

Cystic fibrosis (CF) is characterized by defective cystic fibrosis transmembrane regulator (CFTR) expression and function, associated with abnormal ion transport and mucociliary clearance, and clinical lung disease. Triphosphate nucleotides such as uridine-5'-triphosphate (UTP) and INS 365, may be useful for CF through actions, mediated via P2Y(2) extracellular receptors, on chloride and liquid secretion, and ciliary beat frequency. INS 365 may offer chemical stability advantages over UTP. In a randomized, double-blind, multicenter phase I study, we studied the safety and maximally tolerated dose of escalating, single doses of aerosolized INS 365, in adult and pediatric patients with mild to moderate CF lung disease (FEV(1) > or = 45% predicted). In four successive dose cohorts of adult patients (n = 12 per cohort, age > or = 18 years) and four successive pediatric dose cohorts (n = 12 per cohort, age 5-12 years), patients were randomized 3:1 active/placebo (0.9% saline) to evaluate doses of 20, 40, 80, and 100 mg INS 365 delivered by nebulizer (Pari Star ). Sputum was collected pre- and post-dosing to obtain preliminary results on clinical efficacy. After each dose cohort, a Data Safety Monitoring Committee (DSMC) reviewed the data. Forty-eight adult and 36 pediatric patients completed the protocol (up to 100 mg for adults, 80 mg for pediatric patients). The predominant adverse events were cough, wheezing, chest tightness, and a decrease in FEV(1) (occurring in 8/48 adults, and 5/36 pediatric patients), which occurred predominantly in the 80-mg and 100-mg dose cohorts. Though a few adult patients had a tendency to increase sputum production, there was little consistent effect noted on sputum production in this acute, single-dose study. The data suggest that aerosolized INS 365 is safe when delivered at single doses of up to 40 mg in adults and children with CF, but that higher doses are unlikely to be tolerated.