Airway hyperreactivity in cystic fibrosis. Clinical correlates and possible effects on the course of the disease

CFTR dysfunction in smooth muscle drives TGFβ dependent airway hyperreactivity

BACKGROUND

The primary underlying defect in cystic fibrosis (CF) is disrupted ion transport in epithelia throughout the body. It is unclear if symptoms such as airway hyperreactivity (AHR) and increased airway smooth muscle (ASM) volume in people with CF are due to inherent abnormalities in smooth muscle or are secondary to epithelial dysfunction. Transforming Growth Factor beta 1 (TGFβ) is an established genetic modifier of CF lung disease and a known driver of abnormal ASM function. Prior studies have demonstrated that CF mice develop greater AHR, goblet cell hyperplasia, and ASM hypertrophy after pulmonary TGFβ exposure. However, the mechanism driving these abnormalities in CF lung disease, specifically the contribution of CFTR loss in ASM, was unknown.

METHODS

In this study, mice with smooth muscle-specific loss of CFTR function (Cftrfl/fl; SM-Cre mice) were exposed to pulmonary TGFβ. The impact on lung pathology and physiology was investigated through examination of lung mechanics, Western blot analysis, and pulmonary histology.

RESULTS

Cftrfl/fl; SM-Cre mice treated with TGFβ demonstrated greater methacholine-induced AHR than control mice. However, Cftrfl/fl; SM-Cre mice did not develop increased inflammation, ASM area, or goblet cell hyperplasia relative to controls following TGFβ exposure.

CONCLUSIONS

These results demonstrate a direct smooth muscle contribution to CF airway obstruction mediated by TGFβ. Dysfunction in non-epithelial tissues should be considered in the development of CF therapeutics, including potential genetic therapies.

Reversible Bronchial Obstruction in Primary Ciliary Dyskinesia

BACKGROUND

Inhaled bronchodilators are frequently used among patients with primary ciliary dyskinesia (PCD), although neither the effectiveness nor the prevalence of their use is known, due to the paucity of relevant studies.

METHODS

This is a retrospective analysis of pre- and post-bronchodilator spirometry results, of patients with PCD from two centers. Correlations were examined of bronchodilator response, with asthma and atopy markers.

RESULTS

Of 115 patients, 46 (40%) completed spirometry pre- and post-bronchodilation. Of these, 26 (56.5%) demonstrated reversible airway obstruction (increase in %FEV₁ predicted ≥ 10%). Obstruction reversibility was not found to be associated with a family history of asthma, blood eosinophil level, elevated IgE, or atopy symptoms. Of the 46 patients who completed bronchodilator spirometry, 29 (63%) were regularly using bronchodilators and inhaled corticosteroids.

CONCLUSIONS

More than half of patients with PCD presented with reversible airway obstruction, without any correlation to markers of personal or familial atopy. Inhaled bronchodilators and corticosteroid therapies are commonly used for treating PCD. Evaluating bronchodilator response should be considered, and its effectiveness should be further studied.

Bronchodilator responsiveness in cystic fibrosis children treated for pulmonary exacerbations

BACKGROUND

Cystic fibrosis (CF) pulmonary exacerbations (PEx) are associated with a significant drop in pulmonary function. The clinical value of measuring bronchodilator (BD) responsiveness during treatment for PEx to monitor or predict recovery of lung function is unclear.

METHODS

A retrospective analysis of spirometry with BD response testing obtained during hospital admissions for PEx in pediatric CF patients. Repeated events were included for patients with BD testing during multiple admissions.

RESULTS

Two hundred forty-nine spirometries with BD testing in 102 patients were completed around Day 7 (Days 4-10) of hospital admission for treatment of CF PEx. Median (IQR) forced expiratory volume in 1 s (FEV₁ ) was 70.6% predicted (58.1, 84.6) before the PEx event (best FEV₁ in 6 months before admission), 54.4% (41.5, 66.9) at admission, 62.3% (48.4, 74.7) around Day 7 of admission and 67.1% predicted (53.8, 78.2) at the end of treatment. BD response around Day 7 correlated poorly with FEV₁ before PEx (r = -.16, p = .02) and did not correlate with recovery to baseline FEV₁ at end of treatment (r = .08, p = .22). Only 23/249 (9%) individual tests had a BD response in FEV₁ of ≥12% and 200 ml. BD response was not related to age or severity of lung disease and led to an immediate change in clinical management in only four cases.

CONCLUSIONS

Significant BD response in CF patients treated for PEx is rare, shows poor correlation with baseline pulmonary function and does not correlate with the recovery of FEV₁ with treatment. These data suggest that routine testing for BD response is not indicated during PEx.

Asthma in Cystic Fibrosis: Definitions and Implications of This Overlap Syndrome

PURPOSE OF REVIEW

Cystic fibrosis (CF) is a multisystem, autosomal recessive disease that leads to progressive loss of lung function. Respiratory symptoms for both CF and asthma include cough, wheezing, and dyspnea. There is debate within the CF community on how to best define and distinguish CF-asthma overlap syndrome (CFAOS) from asthma-like features, though CFAOS is well-recognized. We aim to review the epidemiology, diagnosis, and treatment of asthma in CF and explore areas where further research is needed.

RECENT FINDINGS

There has been considerable improvement in the understanding and treatment of asthma over the past two decades leading to novel therapies such as biologic agents that target the airway inflammation in asthmatics based on their asthma phenotype. These therapies are being studied in CFAOS and are promising treatments. This review provides a comprehensive overview of the definition, epidemiology, diagnosis, and current treatment of CFAOS.

Subacute TGFβ Exposure Drives Airway Hyperresponsiveness in Cystic Fibrosis Mice through the PI3K Pathway

Cystic fibrosis (CF) is a lethal genetic disease characterized by progressive lung damage and airway obstruction. The majority of patients demonstrate airway hyperresponsiveness (AHR), which is associated with more rapid lung function decline. Recent studies in the neonatal CF pig demonstrated airway smooth muscle (ASM) dysfunction. These findings, combined with observed CF transmembrane conductance regulator (CFTR) expression in ASM, suggest that a fundamental defect in ASM function contributes to lung function decline in CF. One established driver of AHR and ASM dysfunction is transforming growth factor (TGF) β1, a genetic modifier of CF lung disease. Prior studies demonstrated that TGFβ exposure in CF mice drives features of CF lung disease, including goblet cell hyperplasia and abnormal lung mechanics. CF mice displayed aberrant responses to pulmonary TGFβ, with elevated PI3K signaling and greater increases in lung resistance compared with controls. Here, we show that TGFβ drives abnormalities in CF ASM structure and function through PI3K signaling that is enhanced in CFTR-deficient lungs. CF and non-CF mice were exposed intratracheally to an adenoviral vector containing the TGFβ1 cDNA, empty vector, or PBS only. We assessed methacholine-induced AHR, bronchodilator response, and ASM area in control and CF mice. Notably, CF mice demonstrated enhanced AHR and bronchodilator response with greater ASM area increases compared with non-CF mice. Furthermore, therapeutic inhibition of PI3K signaling mitigated the TGFβ-induced AHR and goblet cell hyperplasia in CF mice. These results highlight a latent AHR phenotype in CFTR deficiency that is enhanced through TGFβ-induced PI3K signaling.

Contractile Properties of Intrapulmonary Airway Smooth Muscle in Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal-recessive disease caused by mutations in the CF transmembrane conductance regulator gene. Many patients with CF have asthma-like symptoms and airway hyperresponsiveness, which are potentially associated with altered airway smooth muscle (ASM) contractility. Our goal in this study was to assess the contractility of the CF intrapulmonary ASM. ASM strips were dissected from human control and CF intrapulmonary airways, and assessed for methacholine-induced shortening velocity, maximal force, and stress. We also assessed isoproterenol responses in maximally methacholine-contracted ASM. ASM strips were then incubated for 16 hours with IL-13 and measurements were repeated. Myosin light chain kinase (MLCK) expression was assessed by Western blotting. Airways were immunostained for morphometry. ASM mass was increased in CF airways, which likely contributes to airway hyperresponsiveness. Although ASM contractile properties were not intrinsically different between patients with CF and control subjects, CF ASM responded differently in the presence of the inflammatory mediator IL-13, showing impairment in β-adrenergic-induced relaxation. Indeed, the percentage of relaxation measured at maximal isoproterenol concentrations in the CF ASM was significantly lower after incubation with IL-13 (46.0% ± 6.7% relaxation) than without IL-13 (74.0% ± 7.7% relaxation, P = 0.018). It was also significantly lower than that observed in control ASM incubated with IL-13 (68.8% ± 4.9% relaxation, P = 0.048) and without IL-13 (82.4% ± 9.9%, P = 0.0035). CF ASM incubated with IL-13 also expressed greater levels of MLCK. Thus, our data suggest that the combination of an increase in ASM mass, increased MLCK expression, and inflammation-induced β-adrenergic hyporesponsiveness may contribute to airway dysfunction in CF.

Common clinical features of CF (respiratory disease and exocrine pancreatic insufficiency)

First described as a disease of the pancreas, cystic fibrosis is a genetically inherited progressive disease affecting multiple organ systems. Pulmonary and pancreatic involvement is common in individuals with cystic fibrosis, and the former is attributable to most of the mortality that occurs with the condition. This chapter provides an overview of a clinical approach to the pulmonary and pancreatic manifestations of cystic fibrosis.

Reversible airway obstruction in cystic fibrosis: Common, but not associated with characteristics of asthma

BACKGROUND

As asthma-like symptoms are common in CF, we evaluated reversible airway obstruction and associated characteristics.

METHODS

Retrospective analysis of charts including spirometry and bronchodilator response.

RESULTS

Of 190 CF patients (103 at Schneider's, 87 at Hadassah), aged 14.4 (4-76) years, median (range), 39% had reversible obstruction (ΔFEV1% predicted ≥12%), associated with younger age (p=0.01) and severe genotype (p=0.02). There was no association with family history of asthma, serum IgE, blood eosinophils, pancreatic status, FEV1<40% predicted, Aspergillus or pseudomonas infection. Of patients with reversible obstruction, 74% were on bronchodilator and 68% on inhaled corticosteroid therapy but 54% and 57% respectively receiving these therapies did not have reversible obstruction.

CONCLUSIONS

Reversible airway obstruction is common in CF, more frequent in younger patients and with severe genotype, with no correlation to markers of atopy or CF clinical severity. Bronchodilator and inhaled corticosteroid therapies are commonly prescribed even without reversible obstruction.

Streptomycin treatment alters the intestinal microbiome, pulmonary T cell profile and airway hyperresponsiveness in a cystic fibrosis mouse model

Cystic fibrosis transmembrane conductance regulator deficient mouse models develop phenotypes of relevance to clinical cystic fibrosis (CF) including airway hyperresponsiveness, small intestinal bacterial overgrowth and an altered intestinal microbiome. As dysbiosis of the intestinal microbiota has been recognized as an important contributor to many systemic diseases, herein we investigated whether altering the intestinal microbiome of BALB/c Cftr(tm1UNC) mice and wild-type littermates, through treatment with the antibiotic streptomycin, affects the CF lung, intestinal and bone disease. We demonstrate that streptomycin treatment reduced the intestinal bacterial overgrowth in Cftr(tm1UNC) mice and altered the intestinal microbiome similarly in Cftr(tm1UNC) and wild-type mice, principally by affecting Lactobacillus levels. Airway hyperresponsiveness of Cftr(tm1UNC) mice was ameliorated with streptomycin, and correlated with Lactobacillus abundance in the intestine. Additionally, streptomycin treated Cftr(tm1UNC) and wild-type mice displayed an increased percentage of pulmonary and mesenteric lymph node Th17, CD8 + IL-17+ and CD8 + IFNγ+ lymphocytes, while the CF-specific increase in respiratory IL-17 producing γδ T cells was decreased in streptomycin treated Cftr(tm1UNC) mice. Bone disease and intestinal phenotypes were not affected by streptomycin treatment. The airway hyperresponsiveness and lymphocyte profile of BALB/c Cftr(tm1UNC) mice were affected by streptomycin treatment, revealing a potential intestinal microbiome influence on lung response in BALB/c Cftr(tm1UNC) mice.

Asthma and cystic fibrosis: a tangled web

Successfully diagnosing concomitant asthma in people with cystic fibrosis (CF) is a challenging proposition, and the utility of conventional diagnostic criteria of asthma in CF populations remains uncertain. Nonetheless, the accurate identification of individuals with CF and asthma allows appropriate tailoring of therapy, and should reduce the unnecessary use of asthma medication in broader CF cohorts. In this review, we discuss the diagnostic challenge posed by asthma in CF, both in terms of clinical evaluation, and of interpretation of pulmonary function testing and non-invasive markers of airway inflammation. We also examine how the role of cross-sectional thoracic imaging in CF and asthma can assist in the diagnosis of asthma in these patients. Finally, we critically appraise the evidence base behind the use of asthma medications in CF populations, with a particular focus on the use of inhaled corticosteroids and bronchodilators. As shall be discussed, the gaps in the current literature make further high-quality research in this field imperative.

Airway hyperresponsiveness in FVB/N delta F508 cystic fibrosis transmembrane conductance regulator mice

BACKGROUND

Airway hyperresponsiveness is a feature of clinical CF lung disease. In this study, we investigated whether the FVB/N ΔF508 CFTR mouse model has altered airway mechanics.

METHODS

Mechanics were measured in 12-14week old FVB/N Cftr(tm1Eur) (ΔF508) mice and wildtype littermates using the FlexiVent small animal ventilator. Lung disease was assayed by immunohistochemistry, histology and bronchoalveolar lavage analysis.

RESULTS

Cftr(tm1Eur) mice presented with increased airway resistance, compared to wildtype littermates, in response to methacholine challenge. No differences in bronchoalveolar cell number or differential, or in tissue lymphocyte, goblet cell or smooth muscle actin levels were evident in mice grouped by Cftr genotype. The bronchoalveolar lavage of Cftr(tm1Eur) mice included significantly increased levels of interleukin 12(p40) and CXCL1 compared to controls.

CONCLUSION

We conclude that the pulmonary phenotype of Cftr(tm1Eur) mice includes airway hyperresponsiveness in the absence of overt lung inflammation or airway remodeling.

Pulmonary function parameters and use of bronchodilators in patients with cystic fibrosis

OBJECTIVE

To analyze pulmonary function parameters and pharmacodynamic response to a bronchodilator, as well as the prescription of bronchodilators, in cystic fibrosis (CF) patients.

METHODS

This was a retrospective cohort study involving patients 6-18 years of age, diagnosed with CF, and followed at a referral center between 2008 and 2010. We evaluated only those patients who were able to perform pulmonary function tests (PFTs). We analyzed FVC, FEV1, and FEF25-75%, expressed as percentages of the predicted values, prior to and after bronchodilator tests (pre-BD and post-BD, respectively), in 312 PFTs. Repeated measures ANOVA and multiple comparisons were used.

RESULTS

The study included 56 patients, divided into two groups: those whose PFT results spanned the 2008-2010 period (n = 37); and those whose PFT results spanned only the 2009-2010 period (n = 19). In the 2008-2010 group, there were significant reductions in post-BD FEV1 between 2008 and 2010 (p = 0.028) and between 2009 and 2010 (p = 0.036), as was also the case for pre-BD and post-BD FEF25-75% in all multiple comparisons (2008 vs. 2009; 2008 vs. 2010; and 2009 vs. 2010). In the 2009-2010 group, there were no significant differences between any of the years for any of the variables studied. Among the 312 PFTs, significant responses to the bronchodilator occurred in only 24 (7.7%), all of which were from patients for whom no bronchodilator had been prescribed during the study period.

CONCLUSIONS

In the CF patients studied, there was loss of pulmonary function, indicating progressive lung disease, over time. The changes were greater for FEF25-75% than for the other variables, which suggests the initial involvement of small airways.

Cystic fibrosis, atopy, asthma and ABPA

The role of atopy on cystic fibrosis (CF) progression remains unclear but evidence suggests that it may influence the appearance of co-morbid conditions such as CF asthma or allergic bronchopulmonary aspergillosis (ABPA). Recognising asthma in patients with CF is not always easy but the identification of atopic markers favours the diagnosis. Physicians should be aware of this fact in order to achieve a better control of respiratory symptoms in patients with CF. Bronchial mucosa inflammation and abnormal mucus predispose to mould colonisation. These patients are at higher risk of allergic sensitisation, especially when atopic susceptibility is present. In the particular case of A. fumigatus, allergic sensitisation precedes ABPA development, which occurs in up to 10% of CF patients. Progression of lung function deterioration is most strikingly pronounced in patients with ABPA. Therefore, sensitisation with A. fumigatus should be regularly tested in patients with CF, especially those at higher risk. Recombinant allergens constitute an important advance in differentiating Aspergillus sensitisation from ABPA itself.

Leukotriene receptor antagonists in children with cystic fibrosis lung disease : anti-inflammatory and clinical effects

Cystic fibrosis (CF) lung disease is characterized by chronic endobronchial infection resulting in progressive pulmonary destruction; this is a major cause of mortality and morbidity. Neutrophils are the primary effector cells responsible for the progressive deterioration of lung function. Peptido-leukotriene B4 antagonists, new anti-inflammatory agents that block the neutrophil-dominated inflammation, could have had the potential for long-term use. A trial on the pharmacokinetics of amelubant administered orally as a single dose of up to 75 mg in pediatric patients with CF and 300 mg in adults, and as a repeated dose of 75 mg and 150 mg, respectively, once daily for 15 days provided evidence that amelubant metabolism in adult and pediatric patients with CF is similar to that in healthy adults. In another study using the same dosage regimen, amelubant appeared to be safe and well tolerated. Safety measures included physical examination, vital signs, spirometry, oximetry, ECG, and clinical laboratory testing. However, a randomized, double-blind, placebo-controlled, multinational, phase II trial (Boehringer Ingelheim 543.45) was conducted to investigate the clinical efficacy of 24 weeks of treatment with amelubant in patients with CF with mild-to-moderate lung disease. Two doses of amelubant (75 and 150 mg) were tested in adult patients (> or = 18 years) and one dose of amelubant (75mg) was tested in pediatric (6-17 years) patients. The trial was terminated early due to a statistically significant increase in the risk of pulmonary-related, serious adverse events in adults receiving amelubant. Cysteinyl leukotrienes, eosinophilic inflammation, and viral infections also contribute to progressive pulmonary destruction in CF. Cysteinyl leukotrienes are potential targets for cysteinyl leukotriene receptor antagonist use. A study on the pharmacokinetics of montelukast in children with CF provided evidence that the dose of montelukast and the administration interval does not need to be modified if the goal is to mimic the serum concentrations used to treat asthma. In a randomized, double-blind, crossover, placebo-controlled study, 16 children with mild CF (median age 9.5 years; vital capacity [VC] >70%) were treated with montelukast (5 to < or =14 years; 5 mg; >14 years; 10 mg) or placebo as a once-daily tablet for 21 days. There was a significant (p < or = 0.02) reduction in serum eosinophil cationic protein levels and eosinophils (p < or = 0.027) with montelukast. However, neither lung function tests (VC, forced expiratory volume in 1 second [FEV1], maximum expiratory flow at 25% of forced VC), nor clinical symptom scores changed significantly. In another study, 26 patients aged 6-18 years with moderate CF (VC between 40% and 69% predicted) received montelukast or placebo for 8 weeks in a 20-week, randomized, double-blind, crossover, placebo-controlled trial. After treatment with montelukast there was a significant improvement in FEV1, peak expiratory flow, and forced expiratory flow between 25% and 75%, and a significant decrease in cough and wheezing scale scores (p < 0.001 for all). Montelukast treatment decreased serum and sputum levels of eosinophil cationic protein and interleukin-8 (IL-8), decreased sputum levels of myeloperoxidase, and increased serum and sputum levels of IL-10 (p < 0.001 for all) compared with placebo. To date, clinical experience and research data on the anti-inflammatory effects of leukotriene receptor antagonists in CF are limited. Multicenter trials with longer observation periods and greater patient numbers are needed to prove the hypothesis that leukotriene receptor antagonists have the potential to ameliorate CF lung disease with long term use.

Serial Lung Function and Responsiveness in Cystic Fibrosis during Early Childhood

In a 4-year prospective study, we evaluated specific airway resistance (sRaw) by whole-body plethysmography, respiratory resistance by the interrupter technique, and respiratory resistance and reactance at 5 Hz by the impulse oscillation technique combined with measurement of responsiveness to bronchodilators and cold air in 30 children (mean [range] age 5.7 [2 to 8] years) with cystic fibrosis (CF). Spirometry was done at school age. Mean sRaw was consistently abnormal: the mean z score (SD) was 2.52 (2.02) (p < 0.001) at the start and was unchanged 36 months later at 2.74 (2.02). Mean z score (SD) for FEV(1) at first satisfactory measurement, at a mean age (range) of 6.1 (4.9-7.5) years was -1.2 (1.2) and was further reduced to -1.85 (1.2) 4 years from inclusion at a mean age (range) of 9.9 (6.8-12) years. Neither respiratory resistance by the interrupter technique nor the impulse oscillation technique demonstrated consistent abnormal levels. Patients with CF as a group did not differ from healthy subjects in responsiveness to bronchodilators and cold air. sRaw may be a useful tool in CF during early childhood. Reduced lung function was documented from consistently abnormal levels of sRaw and FEV1 during the study. Bronchodilator responsiveness and response to cold air challenge were normal.

Associations between bronchial hyperresponsiveness and immune cell parameters in patients with chronic fatigue syndrome

STUDY OBJECTIVE

To examine whether bronchial hyperresponsiveness (BHR) in patients with chronic fatigue syndrome (CFS) is caused by immune system abnormalities.

DESIGN

Prospective comparative study.

SETTING

A university-based outpatient clinic (Vrije Universiteit; Brussels, Belgium).

PARTICIPANTS

One hundred thirty-seven CFS patients and 27 healthy volunteers.

MEASUREMENTS

Pulmonary function testing, histamine bronchoprovocation test, immunophenotyping, and ribonuclease (RNase) latent determination.

RESULTS

Seventy-three of 137 patients presented with BHR, of whom 64 had normal results of the histamine bronchoprovocation test. No significant differences were found in age or sex characteristics between the groups. There were no differences in the RNase L ratio, total lung capacity, or FEV(1)/FVC ratio between CFS patients with or without BHR. The group of patients in whom BHR was present (BHR+) differs most significantly from the control group with eight differences in the immunophenotype profile in the cell count analysis and seven differences in the percentage distribution profile. The group of patients in whom no BHR was detected (BHR-) only differed from the control subjects in CD25+ count and in the percentage of CD25+ cells. We observed a significant increase in cytotoxic T-cell count and in the percentage of BHR+ patients compared to BHR- patients, which is consistent with the significant reduction in percentage naïve T cells.

CONCLUSIONS

These results refute any association between the cleaving of 80 kd RNase L and BHR. Immunophenotyping of our sample confirmed earlier reports on (chronic) immune activation in patients with CFS, compared to healthy control subjects. BHR+ CFS patients have more evidence of immune activation compared to BHR- patients. Inflammation and the consequent IgE-mediated activation of mast cells and eosinophils, as seen in asthma patients, is unlikely to be responsible for the presence of BHR in patients with CFS.

Paediatric bronchiectasis in the twenty-first century: experience of a tertiary children's hospital in New Zealand

OBJECTIVE

Despite its decline in developed countries, bronchiectasis appeared to be a common diagnosis in Auckland, New Zealand children. The aims of this study were: to document the number of children in Auckland with bronchiectasis, their severity, clinical characteristics and possible aetiologies; to assess whether there was a relationship between ethnicity and poverty; and to estimate a crude bronchiectasis prevalence rate for New Zealand.

METHODS

A retrospective review of the case histories of all children attending a tertiary children's hospital in Auckland with bronchiectasis diagnosed by high-resolution chest computed tomography (CT) scan, during the period 1998-2000 was undertaken. Data collected included patient demographics, number of hospitalizations pre- and post-diagnosis, lung function tests, radiology and investigations. The New Zealand deprivation 1996 index was applied to the data to obtain a measure of socio-economic status.

RESULTS

Bronchiectasis was found to be common, with an estimated prevalence of approximately one in 6000 in the Auckland paediatric population. It was disproportionately more common in the Pacific Island and Maori children. In Pacific Island children, bronchiectasis not caused by cystic fibrosis was nearly twice as common in the general population than cystic fibrosis. Socio-economic deprivation and low immunization rates may be significant contributing factors. The bronchiectasis seen was extensive. Ninety-three percent had bilateral disease and 64% had involvement of four or more lobes on chest CT scan. A wide range of comorbidities and underlying aetiologies were evident.

CONCLUSIONS

Paediatric bronchiectasis in Auckland, New Zealand, is common but underresourced. Only the most severe cases are being recognized, providing a significant challenge for paediatric health professionals.

Effectiveness and tolerability of high-dose salmeterol in cystic fibrosis

The efficacy and tolerability of high-dose salmeterol (100 mcg, BID) and albuterol (2.5 mg, BID) were compared with those of albuterol (2.5 mg, BID) in outpatients with cystic fibrosis in a randomized, double-blind, double-dummy, placebo-controlled, crossover study with both short- (4 weeks of each) and long-term (24 weeks of each) treatment periods. The primary outcome measure was the difference in mean change in forced expired volume in 1 sec (FEV(1)) from baseline to the end of each treatment, and secondary measures included changes in forced vital capacity (FVC), forced expiratory flow between 25-75% of FVC (FEF(25-75)), patient-rated weekly symptom scores, number of extra (rescue) albuterol treatments, and number of antibiotic treatments. Tolerability was evaluated by changes in vital signs and adverse events.Thirty-six out of 44 patients enrolled finished the short-term treatment period, and 19 out of 23 who continued the study also finished the long-term treatment period. There was no significant difference in the mean % change in FEV(1) from baseline to completion of 4 weeks with each drug in the short-term treatment period (0.1% vs. 0.06%, albuterol vs. salmeterol; respectively). In the long-term treatment period, there was a significant decrease from baseline in FEV(1) with albuterol vs. salmeterol, as measured after both 12 and 24 weeks of each treatment (-6.2% vs. 1.8%, P = 0.013 after 12 weeks, and -6.5% vs. 1.7%, P = 0.002, after 24 weeks, respectively). In both treatment periods, salmeterol was well-tolerated. While there were more rescue treatments per patient per week with albuterol than with salmeterol treatment in both the short- and long-term periods (0.67 vs. 0.40 and 1.76 vs. 0.74, respectively), rescue treatments were needed significantly more often for only the long-term period with albuterol compared to salmeterol (P = 0.022). Also, there were more antibiotic interventions with albuterol than with salmeterol treatment in both the short- and long-term periods (25 vs. 10 and 56 vs. 42, respectively); however, antibiotics were needed significantly more often for only the short-term period (P = 0.011). In addition, there was a significantly higher symptom score with albuterol vs. salmeterol treatment during the second half of the long-term period (1.24 vs. 0.89, P = 0.001).In conclusion, long-term high-dose salmeterol was equally safe and was associated with better pulmonary function, fewer interventions, and fewer respiratory symptoms compared to standard therapy with albuterol in a population of outpatients with mild to moderate CF.

Airways reactivity in patients with CF

Airways reactivity, hyper-reactivity, and hyper-responsiveness are terms used to describe airways for which there appears to be increased bronchial smooth muscle tone or responsiveness. Some patients with cystic fibrosis (CF) have concomitant asthma causing airway hyperresponsiveness as manifested by recurrent acute symptoms of dyspnea that is impressively responsive to an inhaled beta 2 agonist and/or systemic corticosteroids. However, many others have a degree of bronchodilator responsiveness in the absence of an impressive clinical response to such anti-asthmatic treatment. In contrast to those with asthma, exercise does not induce bronchospasm and can even cause bronchodilatation in patients with CF who have bronchodilator responsiveness in the absence of asthma. The airway hyperresponsiveness of CF also differs in its response to histamine induced bronchospasm which is effectively reversed with ipratropium in patients with CF who symptomatically do not have asthma, whereas ipratropium does not adequately reverse histamine-induced bronchospasm in those with concomitant symptoms of asthma. These and other data suggest that the increased airway reactivity in patients with CF is vagally mediated and results from the airway damage caused by the lung disease. The use of bronchodilators as a routine part of CF lung disease care is controversial, but there is little evidence that treating airway reactivity in patients with CF is of clinical importance as a routine measure in the absence of clinical asthma. Definite subjective improvement in symptoms or improved sputum production when a bronchodilator precedes chest physical therapy should be sought to justify continued use in individual patients.

"CF asthma": what is it and what do we do about it?

The diagnosis of "CF asthma" is problematic and it is difficult to determine which patients have a combination of CF and asthma and which have asthma like symptoms caused by inflammation of the CF lung. This may not matter, however; the relevance lies in the possible approaches to treatment.

Aerosol therapy in cystic fibrosis: a survey of 54 CF centers

Aerosol therapy has become increasingly important in the treatment of lung disease of patients with cystic fibrosis (CF). Still, many questions concerning this therapy remain unanswered. It is unclear at what age aerosol therapy should be started; which aerosolized drugs are essential in the treatment of CF lung disease; which delivery system(s) should be used; and how aerosol therapy should be timed in relation to physiotherapy. We hypothesized that large differences in aerosol treatment practices between CF centers would be present. To investigate this, we performed an observational survey to evaluate different aspects of aerosol therapy. A questionnaire was sent to 102 CF centers in 28 different countries. A completed questionnaire was returned by 54 out of 94 centers (57%). In these 54 centers, 7,324 CF patients were treated. Substantial differences were found in aerosol therapy between centers. Patients below age 1 year were not treated with any form of aerosol therapy in 10% of the centers, while 37.5% of the centers treated all of these patients. The timing of nebulization and physiotherapy varied substantially for many important and expensive drugs. We conclude that many aspects of aerosol therapy in cystic fibrosis need to be executed in a more rational and evidence-based manner than is currently the case.

Good care for people with cystic fibrosis

The improvement in the health and survival of people who have cystic fibrosis (CF) has been due to better treatment developed at major CF centres. The regimens for prevention, early treatment and later stabilization of chronic respiratory infection and for the maintenance of normal nutrition and growth are now largely established. Treatment is life-long, complex and expensive. It should be started early after a diagnosis made following neonatal screening, and before chronic respiratory infection and malnutrition are established. Regular monitoring and input from the expert staff of a CF centre is essential, either on a 'full' or 'shared care' basis; adults with CF should attend a major Adult CF unit. The details of the staff and facilities necessary to achieve good care for CF are discussed, including the details of clinic procedures and annual assessments.

Defining the asthma phenotype for the purpose of genetic analysis

In 1991, we began a project to search for the genetic basis of asthma using linkage analysis. We encountered discord between a history of asthma and physiological measures of variable airflow obstruction and sought to examine the frequency of such occurrences and the issues surrounding phenotyping of patients with asthma. We reviewed our experience in ascertaining the asthma phenotype in 50 nuclear families comprised of 219 subjects (110 male, 109 female). Three respiratory physicians reviewed data including a questionnaire, skin testing, objective measures of variable airflow obstruction [increase in FEV1 > or = 15% following salbutamol 400 micrograms of PC20 (methacholine) < or = 4 mg/ml], and serum for IgE. Thirty-eight percent of subjects had both objective and questionnaire data consistent with asthma (++) whereas 39% had negative objective and negative questionnaire findings (--) (i.e., no asthma). A positive history but negative objective findings occurred in 7% of subjects, 2% had a negative history and positive objective findings. Retesting was requested in 13% of subjects; review of historical data was requested in 1% (i.e., childhood asthma but no present asthma). Retesting was requested for either (a) positive history, negative objective if symptoms were seasonal or the subject was using medications known to affect the challenge study, (b) viral infection within 6 weeks of a positive methacholine study, or (c) technically inadequate study. Overall, after the initial assessment, all members of only 22 families could be catagorized as either ++ or --. The diagnostic group requested at least 1 retest in 19 families and a review of historical records in 2 families. We conclude that discordance between self-reported questionnaire data and laboratory measures of variable airflow limitation is common and will increase the numbers of asthmatic subjects in studies that seek to determine the genetic basis of asthma.

Controlled trial of inhaled budesonide in patients with cystic fibrosis and chronic bronchopulmonary Psuedomonas aeruginosa infection

The efficacy and safety of anti-inflammatory treatment with inhaled glucocorticosteroids in patients with cystic fibrosis (CF) and complicating chronic Pseudomonas aeruginosa (P.a.) lung infection was studied in a placebo-controlled, parallel, double-blind single center trial. Active treatment consisted of budesonide dry powder, 800 microg twice daily, delivered from a Turbuhaler. The study period covered two successive 3-mo intervals between elective courses of intravenous anti-Pseudomonas antibiotics. Fifty-five patients entered the study, with a mean age of 20 yr and a mean FEV1 of 63% of predicted. Analysis of all patients entered, irrespective of trial adherence ("intention to treat"), showed a decrease in FEV1 in the first period of -0.032 L in patients on budesonide versus -0.187 L in patients on placebo (p = 0.08). The corresponding figures for the patients adhering to the protocol during the first period were -0.017 L versus -0.198 L (p < 0.05, confidence interval of the difference: -0.035 to +0.327 L). For all patients entered, as well as for patients adhering to the trial, there was always a trend in favor of budesonide, as judged by changes in FEV1 and FVC in both 3-mo periods. None of the patients had asthma, but the patients on budesonide had a mean improvement in histamine reactivity of +1.15 dose steps over the entire 6-mo period, as opposed to +0.017 dose steps in patients on placebo (p < 0.05). There was also a significant (p = 0.01) correlation between pre-trial histamine reactivity and the change in FEV1 in the first period in patients on budesonide. We conclude that inhaled glucocorticosteroids can be of short-term benefit in patients with CF and chronic P.a. infection and that those patients most likely to benefit from this treatment are patients with hyperreactive airways. Prolonged studies in larger number of patients are necessary to determine the long-term efficacy of this treatment.

Airway responsiveness to hyperosmolar saline challenge in cystic fibrosis: a pilot study

Hyperosmolar aerosols are used to assess airway responsiveness in subjects with asthma. Using a 10% NaCl aerosol, we investigated airway responsiveness in 23 cystic fibrosis (CF) subjects (12 females, 11 males; 19.1 +/- 3.3 years) who had asthma-like symptoms. The pre-challenge predicted forced expiratory volume in 1 second (FEV1) was 74.7 +/- 21.5. The aerosol was generated by a MistO2gen 143A ultrasonic nebulizer and inhaled for 0.5, 1, 2, 4, 8, 8, and 8 minutes or part thereof. Spirometry was performed before and 1 minute after each inhalation period. The challenge was stopped when a > or = 20% fall from the baseline FEV1 was recorded, after the last inhalation period, or when requested by the subject. We recorded different responses to 10% NaCl among subjects. In 7, the FEV1 fell progressively throughout the challenge in a manner similar to asthmatics. By contrast, in 15 subjects the FEV1 was higher at the completion of challenge compared to during challenge, i.e., the fall in FEV1 was transient. In 7 of these subjects, the final FEV1 at the end of the challenge was higher than the pre-challenge FEV1. We conclude that inhaled 10% hyperosmolar saline causes either progressive and sustained or transient airway narrowing during challenge in the majority of CF subjects. The cause of the transient airway narrowing requires further investigation.

Short-term and long-term effects of albuterol aerosol therapy in cystic fibrosis: a preliminary report

The effectiveness of maintenance albuterol aerosol therapy in cystic fibrosis (CF) was assessed by comparing spirometric measurements at the beginning and end of 1 year. Peak expiratory flow rates (PEFR) were measured twice daily to determine bronchodilator responsiveness and spontaneous diurnal variation (SDV), and results were compared with groups of normal and asthmatic children. CF patients not receiving regular albuterol therapy served as a control group. In the treatment group, forced vital capacity (FVC) and forced expiratory volume in the first second (FEV1) were significantly increased (12.2% and 18.4%, respectively) over the course of the treatment year, as contrasted with a significant decrease during the preceding year. During the study year the CF control group had a significant decrease in FEV1 and FEF25-75%, and the difference between treatment and control groups was significant for FVC, FEV1, and FEF25-75%. PEFR increased from the first to the last week of the year-long observation period (from 71.8% to 78.7% of predicted values, P < 0.01). Spontaneous diurnal variations were significantly greater in the CF study group than a group of normal children; SDV decreased significantly in the treatment group during the year of study. A bronchodilator response of > 15% was present in 25.8% of CF patient days, but there was considerable interpatient variability. Frequent bronchodilator responders were accurately predicted by their baseline bronchodilator responsiveness, but not by age or personal or family history of asthma or atopy. No difference in long-term pulmonary function improvements were noted between frequent and infrequent responders. The results suggest that maintenance albuterol aerosol treatments reversed the progressive downward course in lung function in the CF treatment group. A double-blind placebo-controlled study is required to confirm these preliminary findings.

The effects of the inhaled corticosteroid budesonide on lung function and bronchial hyperresponsiveness in adult patients with cystic fibrosis

Bronchial hyperresponsiveness is present in 40-60% of adult patients with cystic fibrosis (CF). Drugs which alter airway hyperresponsiveness have not yet been studied in CF. In this randomized placebo-controlled study, we investigated the effects of an inhaled corticosteroid, budesonide, on lung function and bronchial hyperresponsiveness in adult CF patients, with proven bronchial hyperresponsiveness to histamine. Twelve patients were treated with budesonide, 1600 micrograms day-1, and with placebo during two periods of 6 weeks in a randomized, double-blind, cross-over study. Drug effects were assessed with regard to bronchial hyperresponsiveness to histamine, spirometry and clinical symptom scores. After treatment with budesonide, no significant differences in spirometry were seen, however, bronchial hyperresponsiveness to histamine significantly improved as compared to baseline. Fifty-eight percent of the patients showed at least one doubling-dose increase in PC20 histamine. Daily symptom scores showed small, but statistically significant, improvements in dyspnoea and cough after budesonide treatment. There is increasing evidence suggesting that excessive inflammatory responses contribute to the pulmonary damage that characterizes CF. Treatment with oral corticosteroids improved the clinical course of selected CF patients, but was associated with unacceptable adverse effects. We conclude that daily inhalation of 1600 micrograms day-1 budesonide for 6 weeks induced a small, but significant, improvement in bronchial hyperresponsiveness to histamine, and symptoms of cough and dyspnoea in adult CF patients. Longer observations are needed to establish whether inhaled corticosteroids improve the long term outcome of CF.

[Role of anticholinergic agents in the treatment of cystic fibrosis]

A significant proportion of patients with cystic fibrosis (CF) demonstrate increased airways hyperreactivity, a feature that has been well documented by several authors. This bronchial lability is more pronounced in those with more severe and advanced lung disease. Several mechanisms for this increased airways responsiveness have been proposed such as chronic inflammation with impairment of mucosal permeability, increase in amount of bronchial secretions, systemic autonomic abnormality, increase in incidence of atopy and airway narrowing and changes in airway geometry induced by chronic inflammation. Several studies have assessed the change in FEV1 after beta-agonist or anticholinergic therapy in CF patients and there are studies in which the effect of the combination of drugs was tested. In a group of young CF patients, we found on average a 7% increase in FEV1 after salbutamol and a 10% improvement after ipratropium bromide (IB). After inhaling both drugs, there was a 17% increase in FEV1 from baseline. There were also significant changes in static volumes and airway-resistance measurements when salbutamol and IB were administered in combination. The influence of pretreatment of either normal saline, salbutamol or ipratropium bromide with methacholine was evaluated by Avital and co-workers in a double-blind crossover study. They found an increase in PC20 without a change in baseline FEV1 following salbutamol and an even greater change after IB. These results suggest that the adrenergic agent altered the smooth muscle contractile mechanism, and that muscarinic pathway appears to be important in the pathogenesis of expiratory airflow obstruction in some CF patients. The mechanisms of this cholinergic sensitivity are unclear.(ABSTRACT TRUNCATED AT 250 WORDS)

[Relations between nonspecific bronchial hyperreactivity, diurnal variation of peak expiratory flow and medication requirements in patients with mild asthma]

To assess the relation between non-specific bronchial hyperreactivity, we recorded diurnal peak expiratory flow variation (PFV) and asthma symptoms in 36 individuals with mild allergic asthma. The patients were challenged with methacholine to induce decreases greater than 40% in FEV1, or until a maximum of 200 mg/ml had been administered. Over the next 14 days, PFV was measured three times per day and symptoms and inhaled salbutamol requirements were recorded. In the 11 patients with complete dose-response curves, the geometric mean of diurnal PFV variation (% mean range) was 5.0%; this parameter was 8.3% (p < 0.01) in the 25 subjects whose curves did not reach a plateau. A correlation (r = -0.56, p < 0.001) was found between PC20 and % mean range. PFV for the sample as a whole. In the 11 patients with complete curves, however, no correlation (r = -0.31, p = NS) between % mean range of PFV and PC20 was found. Nor could the plateau (r = 0.19, p = NS) or EC50 (r = -0.26, p = NS) be found for these patients. The geometric mean for PC20 in the 12 subjects who needed salbutamol throughout the 14-day study period after methacholine challenge was 1.06 mg/ml; this parameter was 1.32 mg/ml (p = NS) for those with no symptoms. A plateau was reached by 2 of the 12 patients who experienced asthma symptoms and in 9 of the 24 who were asymptomatic (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Bronchial responsiveness and acute bronchodilator response in chronic obstructive pulmonary disease and diffuse panbronchiolitis

BACKGROUND

Diffuse panbronchiolitis (DPB) is characterised clinically by chronic airflow limitation and respiratory tract infection, and pathologically by chronic bronchiolar inflammation. To elucidate the functional differences between chronic obstructive pulmonary disease (COPD) and DPB the bronchial responsiveness to methacholine was compared in 64 patients with COPD and 32 patients with DPB, and the bronchodilator response was compared in 72 patients with COPD and 49 with DPB.

METHODS

Bronchial responsiveness to methacholine was determined by the dosimeter method and expressed as PD20FEV1, and bronchodilator response was measured as the change in percentage predicted response with 5 mg nebulised salbutamol.

RESULTS

Baseline FEV1 was similar in the two groups of patients. Patients with COPD were more responsive to methacholine than were those with DPB (geometric mean PD20FEV1 8.87 v 48.0 cumulative units). Reversibility of air flow obstruction, expressed as the difference between the percentage predicted postbronchodilator FEV1 and prebronchodilator FEV1, was significantly larger in patients with COPD than in those with DPB (7.87 (6.52)% v 4.16 (4.43)%).

CONCLUSIONS

The observation that patients with DPB differ substantially in bronchial responsiveness from those with COPD is thought to reflect the difference in the mechanisms of these two diseases--that is, airway disease in DPB and more parenchymal disease in the group of patients with COPD. The nature of bronchiolar inflammation in COPD and DPB is also different, possibly explaining the difference in bronchial responsiveness. More fixed airflow limitation as a result of structural bronchiolar lesions in DPB will explain the smaller reversibility of airflow obstruction.

Outcome measures for clinical trials in cystic fibrosis. Summary of a Cystic Fibrosis Foundation consensus conference

The CFF Consensus Conference concluded with a summary of those outcome measures that would be most useful in studies of patients 6 years of age and older and those measures that would be most useful in studies of the younger population (< 6 years of age) (Table). These measures were further divided into biologic markers most appropriate for initial (phase I and phase II) clinical trials and those especially useful in large, multicenter (phase III) pivotal trials. There is an ongoing need to improve the accuracy and validity of currently available measures of biologic activity and clinical efficacy in CF, especially in the younger population. The conference participants recommended that the following eight issues be addressed as soon as possible: (1) definition of pulmonary exacerbation, (2) broadly applicable methods of testing pulmonary function in small children (ideally a single test for all ages), (3) a comprehensive severity-of-disease score for young children, (4) reliable methods of quantifying chest x-ray and CT scan changes in young patients, (5) simple, inexpensive measures of lung inflammation, (6) a centralized, uniform approach to the establishment of data monitoring committees, (7) a quality of well-being scale for small children, and (8) reliable, reproducible aerosol delivery systems with defined characteristics. In addition, participants recommended that better methods be developed for assessing patients' adherence to research protocols.

Wheezing and airflow obstruction during methacholine challenge in children with cystic fibrosis and in normal children

To study wheeze as an indicator of bronchial responses during standardized methacholine challenge (MCH), we used computerized analysis of respiratory sounds in children with cystic fibrosis (CF) and in healthy control subjects. We recorded tracheal and lung sounds from 10 young CF = yCF patients, mean age 5.7 yr (range 4 to 7 yr), 13 older CF = oCF, age 10.5 yr (8 to 18 yr), 7 young normal subjects = yNO, age 5.3 yr (4 to 7 yr), and 11 older normal subjects = oNO, age 11 yr (8 to 16 yr). Spirometry was obtained after each doubling concentration of methacholine until the concentration provoking a > or = 20% fall in FEV1 (PC20) or the end point (8 mg/ml) was reached. Sound and calibrated flow signals were recorded on tape and later analyzed by respirosonography. The concentration of methacholine associated with wheeze (PCw) was noted. Wheezing was quantified by its duration during inspiration (Tw/TI) and expiration (TW/TE). We found a positive response to MCH in 11 of 13 oCF (PC20 0.75 mg/ml, range 0.08 to 3.0) and in 3 of 11 oNO (PC20 4.2 mg/ml, range 2.5 to 6.5). Wheezing occurred in 6 oCF (PC20 < 8 mg/ml). In 7 yCF PC20 or PCW developed (1.51 mg/ml, range 0.125 to 4.0) versus 4 yNO (4.0 mg/ml, range 2.0 to 8.0). In 10 oCF subjects who performed MCH on three occasions within a 2-wk period, both positive and negative wheeze responses were reproducible. Patients who wheezed had a lower FRC compared with patients who did not (109 versus 147% of predicted, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cystic fibrosis

Cystic fibrosis, an autosomal recessive disorder, is the most common genetic disease of Caucasians. One in 25 Caucasians are carriers of the gene. The gene is found far less commonly in other races. There are over 230 different alleles of the gene, located on the 7th chromosome. The gene encodes for a membrane protein that functions as an ion channel. The survival of cystic fibrosis patients has been gradually increasing, with a mean survival in 1990 of 28 years. If the current trend of improved survival continues, it is estimated that half of cystic fibrosis patients will be over 18 years old by 1996. Disease is found in many organs including the lungs, sinuses, pancreas, gastrointestinal tract, hepatobiliary system, sweat glands and reproductive tract. The majority of patients die of pulmonary disease. The airways become chronically colonized with bacteria that cannot be eradicated, leading to bronchitis, bronchiectasis, and finally, pulmonary fibrosis with respiratory failure. The pulmonary disease may be complicated by massive hemoptysis and pneumothorax. Patient survival rates have increased because of antibiotic therapy and improved nutrition with pancreatic enzyme replacements. New treatments for the pulmonary disease are under clinical trial and include antiproteases, amiloride, a sodium channel blocker, and DNase. The insertion of the normal cystic fibrosis allele into an animal model using a modified adenovirus with effective transcription suggests that gene therapy may be possible in the future, but safety and technical problems have to be addressed.

Response to inhaled bronchodilators and nonspecific airway hyperreactivity in children with cystic fibrosis

We tested the hypothesis that children with CF who have a significant response to bronchodilator (BD) would respond positively to standard methacholine (Mch) challenge. Our objective was to correlate the response to BD with the concentration that produced a 20% fall (PC20) in forced expiratory volume in 1 second (FEV1). We studied 22 patients (12 males), aged 10.5 +/- 0.7 years (mean +/- SE), with a Shwachman-Kulczycki score 82 +/- 2.6 and baseline FEV1 of 80 +/- 4.5% predicted. Baseline expiratory flows, static lung volumes, and airway resistance were measured before and 30 min after inhaled salbutamol. On a separate day, within 2 weeks, a Mch challenge was given, with doubling concentrations from 0.03 to 8.0 mg/mL. A positive challenge was defined as a PC20 less than or equal to 2.0 mg/mL, and a positive response to BD as a greater than 6% of FEV1 increase. Mch challenge yielded 17 responders (R) with a PC20 of 0.5 +/- 0.1 mg/mL, and 5 nonresponders (NR) with a PC20 of 8.8 +/- 2.9 mg/mL. Baseline FEV1 was 77 +/- 5.3% predicted in R compared to 89 +/- 6.3% in NR (P = less than 0.001). History of springtime rhinitis was positive in 9/17 R and 2/5 NR. No significant correlation was found between baseline FEV1 and PC20, or between change in FEV1 post-BD and PC20. A greater than 6% increase in FEV1 was seen in 14/17 R (83% sensitivity) and in none of the 5 NR (100% specificity). In R, 8/17 patients had baseline FEV1 less than 80% predicted, compared to 1/5 in NR.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of salbutamol and ipratropium bromide in decreasing bronchial hyperreactivity in children with cystic fibrosis

A proportion of patients with cystic fibrosis (CF) suffer from increased airway hyperreactivity but their response to bronchodilators is variable. Adrenergic agents may produce an increase, no change or a decrease in forced expiratory volume in 1 second (FEV1). We hypothesized that the variable response might be related to poor aerosol distribution caused by the presence of secretions. Therefore, in 11 children with CF and airway hyperreactivity the influence of pretreatment with either 0.9% saline, salbutamol, or ipratropium bromide on the methacholine challenge test was evaluated in a double-blind, randomized, cross-over study. FEV1 (mean +/- S.E.) did not change following pretreatment with saline, salbutamol, or ipratropium (1.64 +/- 0.22, 1.63 +/- 0.16 and 1.67 +/- 0.19, respectively). All patients demonstrated airway hyperreactivity with a PC20 below 8 mg/mL (geometric mean, 0.41 mg/mL) after saline pretreatment. Salbutamol inhalation significantly increased the PC20 to 1.24 mg/mL (P less than 0.01), but ipratropium bromide was found to be even more effective than salbutamol (PC20 = 7.37 mg/mL) (P less than 0.0001). We conclude that the variable response to bronchodilator is not secondary to impaired aerosol distribution since ipratropium bromide effectively blocked the response to methacholine. The improvement in PC20 without a change in baseline FEV1 following salbutamol suggests that the adrenergic agent altered the contractile mechanism of smooth muscle.

A controlled trial of long-term bronchodilator therapy in cystic fibrosis

To evaluate the effect of long-term bronchodilator therapy in CF patients with demonstrated bronchial hyperresponsiveness, we first performed methacholine challenges to determine responsiveness, then entered 27 patients (16 methacholine responders and 11 nonresponders) into a two-month double-blind crossover trial of albuterol, 90 micrograms by inhalation four times a day vs placebo. Among the responders, daily PEFR measures improved significantly more during treatment with albuterol (12 +/- 32 L/min) than with placebo (-0.4 +/- 19 L/min; p less than 0.05). In addition, a clinically important level of improvement in PEFR (15 percent increase) was reached significantly more frequently in the responders. Methacholine nonresponders had no change in PEFR on either albuterol or placebo. Daily symptom scores as well as spirometry measurements at biweekly visits did not show significant changes. We conclude that long-term therapy with inhaled albuterol improves lung function in CF patients, but only in those with bronchial hyperresponsiveness as demonstrated by methacholine challenge.

The clinical value of pharmacologic bronchoprovocation challenge

Pharmacologic bronchoprovocation challenge (PBC) can be of considerable clinical value in patients in the pediatric age group and adults because bronchial hyperresponsiveness is present in virtually all symptomatic asthmatics and it can be accurately, reliably, and safely demonstrated by PBC. The principal, proven indication for performing PBC is to rule out or help rule in the diagnostic possibility of asthma as the cause of any unexplained chest complaints in patients with normal or near normal spirometric values.

The relationship between atopy and cystic fibrosis

The incidence and clinical significance of allergy in cystic fibrosis have been discussed. There is little evidence that the high prevalence of positive allergy skin tests in CF is a clinical manifestation of a hypersensitivity lung disease complicating the primary pulmonary disorder, except in the special case of allergic bronchopulmonary aspergillosis. The lung disease of CF appears to be caused by excessive bronchial secretions and recurrent infection that are the result of abnormal ion transport across the apical membrane of the respiratory epithelial cell. There are two important questions concerning the allergic reactions: Are they clinically significant, and, why do they occur? The former question is partly resolved by the data presented, although well-controlled studies of intervention would help to resolve it further. The cause of these reactions, which occur particularly in relationship to the mold Aspergillus fumigatus, is unknown but the author is inclined to the view that they are the result of recurrent infection that induces heightened immunologic reactivity to inhaled allergens. The significance of AF may be simply that this mold has a "predilection for diseased airways" or may be more complex; for example, owing to abnormal ion composition in respiratory secretions, abnormal lectin expression by CF respiratory epithelial cells, or selective filtration by the airways based on particle size.

The inhaled bronchodilators ipratropium bromide and metaproterenol in adults with CF

Ten patients with CF who were more than 18 years old, participated in a double-blind, placebo-controlled study evaluating the efficacy of inhaled ipratropium bromide and metaproterenol as bronchodilators. The mean FEV1 of the group improved 17.1 percent after treatment with ipratropium bromide, 12.5 percent after metaproterenol treatment, and 16.6 percent after treatment with both of these medications together. There was no significant difference between these responses and patients who responded to one treatment tended to respond to the others. The side effects with these medications were minimal. When compared with patients in previous studies, our patients, who were much older as a group, demonstrated a greater degree of bronchodilation with ipratropium bromide and metaproterenol, as well as a greater degree of bronchoconstriction with placebo.