Effect of inhaled steroids on airway hyperresponsiveness, sputum eosinophils, and exhaled nitric oxide levels in patients with asthma

BACKGROUND: Airway hyperresponsiveness, induced sputum eosinophils, and exhaled nitric oxide (NO) levels have all been proposed as non-invasive markers for monitoring airway inflammation in patients with asthma. The aim of this study was to compare the changes in each of these markers following treatment with inhaled glucocorticosteroids in a single study. METHODS: In a randomised, double blind, placebo controlled, parallel study 25 patients with mild asthma (19-34 years, forced expiratory volume in one second (FEV1) >75% predicted, concentration of histamine provoking a fall in FEV1 of 20% or more (PC20) <4 mg/ml) inhaled fluticasone propionate (500 microg twice daily) for four weeks. PC20 to histamine, sputum eosinophil numbers, and exhaled NO levels were determined at weeks 0, 2, and 4, and two weeks after completing treatment. Sputum was induced by inhalation of hypertonic (4.5%) saline and eosinophil counts were expressed as percentage non-squamous cells. Exhaled NO levels (ppb) were measured by chemiluminescence. RESULTS: In the steroid treated group there was a significant increase in PC20, decrease in sputum eosinophils, and decrease in exhaled NO levels compared with baseline at weeks 2 and 4 of treatment. Subsequently, each of these variables showed significant worsening during the two week washout period compared with week 4. These changes were significantly different from those in the placebo group, except for the changes in sputum eosinophils and exhaled NO levels during the washout period. There were no significant correlations between the changes in the three markers in either group at any time. CONCLUSIONS: Treatment of asthmatic subjects with inhaled steroids for four weeks leads to improvements in airway hyperresponsiveness to histamine, eosinophil counts in induced sputum, and exhaled nitric oxide levels. The results suggest that these markers may provide different information when monitoring anti-inflammatory treatment in asthma.     

Failure of sputum eosinophilia after eotaxin inhalation in asthma

BACKGROUND: Eotaxin is a chemokine specific for eosinophils and may play an important role in eosinophil recruitment in asthma. The effects of eotaxin inhalation on sputum and blood eosinophils, exhaled nitric oxide (NO), and bronchial responsiveness were determined. METHODS: Eotaxin was administered by nebulisation to asthma patients in three studies: (1) an open dose finding study with eotaxin (5, 10 and 20 microg) to two asthmatic subjects; (2) a randomised placebo controlled study with 20 microg eotaxin to five asthmatic subjects and five normal volunteers; and (3) a randomised placebo controlled study with 40 microg eotaxin to nine asthmatics. Forced expiratory volume in 1 second (FEV(1)), exhaled NO, and blood eosinophils were measured before and hourly for 5 hours after nebulisation and at 24 and 72 hours. Methacholine bronchial challenge and sputum induction were performed before and at 5, 24, and 72 hours after nebulisation. RESULTS: In the two placebo controlled studies there was no change in sputum eosinophil count and sputum eosinophilic cationic protein concentration after eotaxin inhalation compared with placebo. FEV(1), exhaled NO, and methacholine PC(20) did not change. However, high dose eotaxin (40 microg) induced an increase in sputum neutrophil count compared with placebo (p<0.05). CONCLUSIONS: Inhaled eotaxin up to 40 microg induced no changes in sputum eosinophil count but at 40 microg it increased the sputum neutrophil count. The significance of this finding is unknown.     

Long term clinical comparison of single versus twice daily administration of inhaled budesonide in moderate asthma.

BACKGROUND--Inhaled steroids are widely used in the treatment of mild to moderate asthma. However, long term compliance with inhaled steroids is poor and administration of a single daily dose may improve compliance. METHODS--A double blind, randomised study was performed to determine whether inhaled steroids given once daily at bedtime are as efficacious as a twice daily regimen in the long term maintenance of moderate asthmatic patients. Forty adults of mean age 37 years with moderate asthma (mean (SE) forced expiratory volume in one second (FEV1) 73.6 (1.4)% predicted, mean morning peak expiratory flow (PEF) 328 l/min) were randomised to receive either a twice daily dose (400 micrograms morning and bedtime) of inhaled budesonide (group A) or a once daily dose of 800 micrograms (group B) and were followed for a period of 12 months. Asthma symptom scores (assessed according to a modified Borg scale), inhaled beta 2 agonist consumption, and peak expiratory flow rates were recorded daily. Spirometry and airways responsiveness to methacholine (PC20) were measured at the end of each period of three months of treatment. RESULTS--There was no difference between the two groups at baseline and during the follow up period in the PC20 for methacholine. However, a difference was seen between the two groups in the mean daily number of beta 2 agonist inhalations (1.4 (0.1) puffs/patient/day in group A v 2.3 (0.1) in group B), the PEF variability (episodes of decrease in PEF of > 20%) (0.22 (0.01) episodes/patient/day in group A v 0.40 (0.02) in group B), and for asthma symptom scores (0.30 (0.04) in group A v 0.42 (0.06) in group B) for the 12 month period of the study. CONCLUSIONS--Although both regimens provide good clinical control, twice daily doses of 400 micrograms inhaled budesonide are more effective than a single dose of 800 micrograms at bedtime in the long term control of stable moderate asthma.     

Effects of inhaled budesonide on spirometric values, reversibility, airway responsiveness, and cough threshold in smokers with chronic obstructive lung disease.

Inhaled corticosteroids are known to reduce respiratory symptoms and airway responsiveness in allergic patients with asthma. The aim of the present randomised, double blind study was to assess the effect of eight weeks' treatment with inhaled budesonide in non-allergic smokers with chronic obstructive lung disease. Twenty four subjects (23 male) entered the study. Their ages ranged from 40 to 70 (mean 57) years, with a mean of 35 (range 9-80) pack years of smoking; the mean FEV1 was 53% (range 32-74%) predicted and geometric mean PC20 (histamine concentration causing a 20% fall in FEV1) 0.96 (range 0.07-7.82) mg/ml. After a two week washout, single blind, placebo period, 12 patients were allocated to treatment with budesonide 1600 microgram/day and 12 to placebo for eight weeks. The only additional drug to be taken was ipratropium bromide "if needed." Twenty one patients completed the study, 10 in the budesonide group and 11 in the placebo group. The standard deviation of the difference between duplicate measurements of PC20 histamine and citric acid cough threshold made two weeks apart was below one doubling dose step. There was a significant reduction in dyspnoea in the budesonide group, but otherwise no change in symptom scores or use of ipratropium bromide over the eight weeks of treatment within or between the two groups. No significant differences in spirometric values, peak expiratory flow, PC20 histamine, or citric acid cough threshold were found between the groups. Although differences were not significant, some of the changes showed a trend in favour of budesonide. Whether a longer observation period would show a significant influence of inhaled corticosteroids in patients with chronic obstructive lung disease remains to be determined.     

Dose-dependent onset and cessation of action of inhaled budesonide on exhaled nitric oxide and symptoms in mild asthma

BACKGROUND: Dose dependent anti-inflammatory effects of inhaled corticosteroids in asthma are difficult to demonstrate in clinical practice. The anti-inflammatory effect of low dose inhaled budesonide on non-invasive exhaled markers of inflammation and oxidative stress were assessed in patients with mild asthma. METHODS: 28 patients entered a double blind, placebo controlled, parallel group study and were randomly given either 100 or 400 micro g budesonide or placebo once daily, inhaled from a dry powder inhaler (Turbohaler), for 3 weeks followed by 1 week without treatment. Exhaled nitric oxide (NO), exhaled carbon monoxide (CO), nitrite/nitrate, S-nitrosothiols, and 8-isoprostanes in exhaled breath condensate were measured four times during weeks 1 and 4, and once a week during weeks 2 and 3. RESULTS: A dose-dependent speed of onset and cessation of action of budesonide was seen on exhaled NO and asthma symptoms. Treatment with 400 micro g/day reduced exhaled NO faster (-2.06 (0.37) ppb/day) than 100 micro g/day (-0.51 (0.35) ppb/day; p<0.01). The mean difference between the effect of 100 and 400 micro g budesonide was -1.55 ppb/day (95% CI -2.50 to -0.60). Pretreatment NO levels were positively related to the subsequent speed of reduction during the first 3-5 days of treatment. Faster recovery of exhaled NO was seen after stopping treatment with budesonide 400 micro g/day (1.89 (1.43) ppb/day) than 100 micro g/day (0.49 (0.34) ppb/day, p<0.01). The mean difference between the effect of 100 and 400 micro g budesonide was 1.40 ppb/day (95% CI -0.49 to 2.31). Symptom improvement was dose-dependent, although symptoms returned faster in patients treated with 400 micro g/day. A significant reduction in exhaled nitrite/nitrate and S-nitrosothiols after budesonide treatment was not dose-dependent. There were no significant changes in exhaled CO or 8-isoprostanes in breath condensate. CONCLUSION: Measurement of exhaled NO levels can indicate a dose-dependent onset and cessation of anti-inflammatory action of inhaled corticosteroids in patients with mild asthma.     

Relationship between exhaled nitric oxide and mucosal eosinophilic inflammation in mild to moderately severe asthma

BACKGROUND: Exhaled levels of nitric oxide (NO) are raised in asthma but the relationship between exhaled NO levels and a direct measure of airway inflammation has not been investigated in asthmatic patients treated with inhaled steroids. METHODS: The relationship between exhaled NO levels, clinical measures of asthma control, and direct markers of airway inflammation were studied in patients with asthma treated with and without inhaled corticosteroids. Thirty two asthmatic patients (16 not using inhaled steroids and 16 using inhaled beclomethasone dipropionate, 400-1000 microg/day) were monitored with respect to measures of asthma control including lung function, symptom scores, medication usage, and variability of peak expiratory flow (PEF) for one month. Measurements of exhaled NO and fibreoptic bronchoscopy were performed at the end of the monitoring period. Bronchial mucosal biopsy specimens were stained with an anti-MBP antibody for quantification of eosinophils. RESULTS: There was no significant difference in lung function, symptom scores, or medication usage between the two groups, but there was a significant difference in PEF variability (8.7 (1.2)% in steroid naive patients versus 13.6 (1.9)% in steroid treated patients, p<0.05) and exhaled NO levels (9.9 (3.5) ppb in steroid naive patients versus 13.6 (2.0) ppb in steroid treated patients, p<0.05). There was no correlation between exhaled NO and mucosal eosinophils, or between NO and conventional measures of asthma control. There was a significant correlation between mucosal eosinophils and lung function (r = -0.43, p<0.05). CONCLUSIONS: Exhaled NO levels do not reflect airway mucosal eosinophilia and these markers reflect different aspects of airway inflammation. The clinical usefulness of exhaled NO needs to be determined in prospective longitudinal studies.     

Comparative adrenal suppression with inhaled budesonide and fluticasone propionate in adult asthmatic patients.

BACKGROUND: A study was performed to compare the adrenal suppression caused by inhaled fluticasone propionate and budesonide on a microgram equivalent basis, each given by metered dose inhaler to asthmatic patients. METHODS: Twelve asthmatic patients of mean age 29.9 years, with a forced expiratory volume in one second (FEV1) 92.9% predicted and forced expiratory flow 25-75% (FEF25-75) 69.5% predicted, on less than or equal to 400 micrograms/day inhaled corticosteroid, were studied in a double blind placebo controlled crossover design comparing single doses of inhaled budesonide 400, 1000, 1600, 2000 micrograms and fluticasone propionate 500, 1000, 1500, 2000 micrograms. Doses were administered at 22.00 hours by metered dose inhaler with mouth rinsing and measurements were made in the laboratory 10 hours later. RESULTS: Serum cortisol levels compared with placebo (mean 325.2 nmol/l) were suppressed by fluticasone at doses of 1500 micrograms (211.6 nmol/l) and 2000 micrograms (112.3 nmol/l) and by budesonide at 2000 micrograms (243.4 nmol/l). Fluticasone propionate 2000 micrograms produced lower absolute serum cortisol levels than budesonide 2000 micrograms (95% CI for difference 42.9 to 219.2). The dose ratio (geometric mean) for the relative potency was 2.89 fold (95% CI 1.19 to 7.07). In terms of percentage suppression versus placebo, fluticasone propionate also produced greater effects (means and 95% CI for difference): budesonide 1600 micrograms (16.0) versus fluticasone propionate 1500 micrograms (40.9) (95% CI -0.6 to 50.6), budesonide 2000 micrograms (26.0) versus fluticasone 2000 micrograms (65.2) (95% CI 10.5 to 67.8). Individual serum cortisol levels at the two highest doses showed 15 of 24 patients below the normal limit of the reference range (150 nmol/l) for fluticasone and five of 24 for budesonide. Fluticasone propionate also caused greater ACTH suppression than budesonide (as % versus placebo): budesonide 1600 micrograms (12.0) versus fluticasone propionate 1500 micrograms (31.9) (95% CI 7.6 to 32.1), budesonide 2000 micrograms (13.5) versus fluticasone propionate 2000 micrograms (44.4) (95% CI 13.2 to 48.7). For overnight 10 hour urinary cortisol (nmol/10 hours) there was a difference between the lowest doses of the two drugs: budesonide 400 micrograms (37.2) versus fluticasone propionate 500 micrograms (19.9) (95% CI 6.9 to 27.8). CONCLUSIONS: Like budesonide the systemic bioactivity of fluticasone propionate is mainly due to lung vascular absorption. Fluticasone propionate exhibited at least twofold greater adrenal suppression than budesonide on a microgram equivalent basis in asthmatic patients.     

Effect of montelukast added to inhaled budesonide on control of mild to moderate asthma

BACKGROUND: Proinflammatory leukotrienes, which are not completely inhibited by inhaled corticosteroids, may contribute to asthmatic problems [corrected]. A 16 week multicentre, randomised, double blind, controlled study was undertaken to study the efficacy of adding oral montelukast, a leukotriene receptor antagonist, to a constant dose of inhaled budesonide. METHODS: A total of 639 patients aged 18-70 years with forced expiratory volume in 1 second (FEV(1)) > or =55% predicted and a minimum predefined level of asthma symptoms during a 2 week placebo run in period were randomised to receive montelukast 10 mg (n=326) or placebo (n=313) once daily for 16 weeks. All patients received a constant dose of budesonide (400-1600 microg/day) by Turbuhaler throughout the study. RESULTS: Mean FEV(1) at baseline was 81% predicted. The median percentage of asthma exacerbation days was 35% lower (3.1% v 4.8%; p=0.03) and the median percentage of asthma free days was 56% higher (66.1% v 42.3%; p=0.001) in the montelukast group than in the placebo group. Patients receiving concomitant treatment with montelukast had significantly (p<0.05) fewer nocturnal awakenings and significantly (p<0.05) greater improvements in beta agonist use and morning peak expiratory flow rate (PEFR). CONCLUSIONS: For patients with mild airway obstruction and persistent asthma symptoms despite budesonide treatment, concomitant treatment with montelukast significantly improves asthma control.     

Effects of cessation of terbutaline treatment on airway obstruction and responsiveness in patients with chronic obstructive pulmonary disease.

BACKGROUND: Cessation of regular therapy with inhaled beta 2 agonists in patients with asthma may lead to a temporary deterioration of lung function and airway responsiveness. Few such studies have been reported in patients with chronic obstructive pulmonary disease (COPD), so an investigation was carried out to determine whether rebound airway responsiveness and rebound bronchoconstriction also occurs in COPD and if there is any relationship with the dose of beta 2 agonist being used. METHODS: Lung function (forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF)), airway responsiveness (PC20 methacholine (PC20)) and symptoms were assessed in a double blind, placebo controlled crossover study during and after cessation of two weeks regular treatment with placebo, and low dose (250 micrograms) and high dose (1000 micrograms) inhaled terbutaline via a dry powder inhaler (Turbohaler) all given three times a day. Sixteen non-allergic patients with COPD of mean (SD) age 58.7 (6.5) years, FEV1 57.1 (12.8)% of predicted, and reversibility on 1000 micrograms terbutaline of 4.5 (3.5)% predicted were studied. PC20 and FEV1 were measured 10, 14, 34 and 82 hours after the last inhalation of terbutaline or placebo. Measurements performed at 10, 14, and 34 hours were expressed relative to 82 hour values in each period, transformed into an area under the curve (AUC) value and analysed by ANOVA. RESULTS: Mean morning and evening PEF increased during terbutaline treatment. PC20 and FEV1 did not change after cessation of terbutaline treatment. CONCLUSIONS: Cessation of regular treatment with both low and high dose inhaled terbutaline does not result in a rebound bronchoconstriction and rebound airway responsiveness in patients with COPD.     

Effects of corticosteroids on bronchodilator action in chronic obstructive lung disease.

BACKGROUND: Short term treatment with corticosteroids does not usually reduce airflow limitation and airway responsiveness in patients with chronic obstructive lung disease. We investigated whether corticosteroids modulate the effects of inhaled salbutamol and ipratropium bromide. METHODS: Ten non-allergic subjects with stable disease were investigated; eight completed the randomised, double blind, three period cross over study. Treatment regimens consisted of 1.6 mg inhaled budesonide a day for three weeks, 40 mg oral prednisone a day for eight days, and placebo. After each period cumulative doubling doses of salbutamol, ipratropium, a combination of salbutamol and ipratropium, and placebo were administered on separate days until a plateau in FEV1 was reached. A histamine challenge was then performed. RESULTS: At the end of placebo treatment mean FEV1 was 55.5% predicted after inhaled placebo, 67.9% predicted after salbutamol and 64.0% predicted after ipratropium. Compared with the results after the placebo period the FEV1 with salbutamol increased by 0.7% predicted after treatment with budesonide and by 0.7% predicted after treatment with prednisone; the FEV1 with ipratropium increased by 0.7% predicted after budesonide and by 4.8% predicted after prednisone; none of these changes was significant. After placebo treatment the geometric mean PC20 was 0.55 mg/ml after placebo, 1.71 mg/ml after salbutamol and 0.97 mg/ml after ipratropium. Compared with the placebo period the PC20 with salbutamol was increased by 0.86 doubling concentrations after treatment with budesonide, and by 0.67 doubling concentrations after prednisone; the PC20 with ipratropium increased by 0.03 and 0.34 doubling concentrations after budesonide and after prednisone respectively compared with placebo; none of these changes was significant. CONCLUSIONS: In non-allergic subjects with chronic obstructive lung disease short term treatment with high doses of inhaled or oral corticosteroids does not modify the bronchodilator response to salbutamol or ipratropium or the protection provided by either drug against histamine. Salbutamol produces greater protection from histamine induced bronchoconstriction than ipratropium.     

Dose equivalence and bronchoprotective effects of salmeterol and salbutamol in asthma

BACKGROUND: Salbutamol is the most widely prescribed short acting beta 2 agonist and salmeterol is the first long acting inhaled beta 2 agonist. The dose equivalence of salmeterol and salbutamol is disputed. Estimates of weight-for-weight dose ratio have ranged from 1:2 to 1:16. A study was undertaken to clarify the true dose ratio. METHODS: The bronchoprotection afforded against repeated methacholine challenge by inhaled salmeterol 25 micrograms and 100 micrograms and salbutamol 100 micrograms and 400 micrograms was compared in a randomised, double blind, placebo controlled, crossover trial. Subjects were 16 stable asthmatics with a baseline forced expiratory volume in one second (FEV1) of > or = 65% predicted, screening concentration provoking a fall in FEV1 of 20% (PC20FEV1) of < or = 8mg/ml, and a shift in PC20FEV1 of more than two doubling concentration steps following inhalation of salbutamol 400 micrograms. On five separate occasions subjects underwent methacholine challenge before and 30 and 120 minutes after drug administration. PD20FEV1 was calculated for each challenge. FEV1 at 90 minutes after drug administration was also recorded. RESULTS: Bronchoprotection afforded by salmeterol was increased at 120 minutes compared with 30 minutes and protection by salbutamol was decreased. Protection by both doses of salmeterol was similar to salbutamol 100 micrograms at 30 minutes but significantly greater at 120 minutes. FEV1 at 90 minutes was significantly greater after salmeterol 100 micrograms than after placebo, but there were no other significant differences between treatments. Maximal observed protection was equivalent for salmeterol 100 micrograms and salbutamol 400 micrograms. CONCLUSIONS: The data are compatible with a weight-for- weight dose ratio for salmeterol:salbutamol of < or = 1:4.




     

Effects of inhaled tumour necrosis factor alpha in subjects with mild asthma

BACKGROUND: Inhaled tumour necrosis factor alpha (TNF alpha) has previously been shown to induce airway neutrophilia and increased airway reactivity in normal subjects. It was hypothesised that a similar challenge would increase airway reactivity in those with mild asthma, but that the inflammatory profile may differ. METHODS: Ten mild asthmatic subjects were recruited on the basis of clinical asthma and either a sensitivity to methacholine within the range defined for asthma or a 20% improvement in forced expiratory volume (FEV(1)) after 200 micro g salbutamol. Subjects inhaled either vehicle control or 60 ng recombinant human (rh)TNF alpha and were studied at baseline, 6, 24, and 48 hours later. Variables included spirometric parameters, methacholine provocative concentration causing a 20% fall in FEV(1) (PC(20)), induced sputum differential cell count, relative sputum level of mRNA of interleukins (IL)-4, IL-5, IL-9, IL-14, IL-15 and TNF alpha, and the exhaled gaseous markers of inflammation, nitric oxide and carbon monoxide. RESULTS: PC(20) showed an increase in sensitivity after TNF alpha compared with control (p<0.01). The mean percentage of neutrophils increased at 24-48 hours (24 hour control: 1.1 (95% CI 0.4 to 2.7) v 9.2 (95% CI 3.5 to 14.9), p<0.05), and there was also a rise in eosinophils (p=0.05). Relative levels of sputum mRNA suggested a rise in expression of TNF alpha, IL-14, and IL-15, but no change in IL-4 and IL-5. Spirometric parameters and exhaled gases showed no significant change. CONCLUSION: The increase in airway responsiveness and sputum inflammatory cell influx in response to rhTNF alpha indicates that TNF alpha may contribute to the airway inflammation that characterises asthma.     

Correlation between change in pulmonary function and suppression of reactive nitrogen species production following steroid treatment in COPD

BACKGROUND: Reactive nitrogen species (RNS) have a number of inflammatory actions and the production of these molecules has been reported to be increased in the airways of patients with chronic obstructive pulmonary disease (COPD), which suggests that they may be involved in the inflammatory and obstructive process in COPD. METHODS: The relationship between the reduction in RNS and the improvement in pulmonary function was studied in 18 patients with COPD following steroid treatment (800 micro g beclomethasone dipropionate inhalation for 4 weeks). Twelve patients were treated with inhaled steroids and the others received placebo treatment. Forced expiratory volume in 1 second (FEV(1)) and airway responsiveness to histamine were measured before and after treatment. Induced sputum cells were stained with anti-nitrotyrosine antibody, a footprint of RNS, and RNS formation was assessed by measuring nitrotyrosine immunoreactivity. The immunoreactivity of inducible nitric oxide synthase (iNOS) in induced sputum and exhaled NO levels were also measured. RESULTS: Treatment with steroids resulted in a significant reduction in both nitrotyrosine and iNOS immunoreactivity in sputum cells compared with pretreatment levels (both p<0.01). The reduction rates in both parameters were significantly related (p<0.05). The reduction in nitrotyrosine and iNOS immunoreactivity was correlated with the improvement in FEV(1) (p<0.05) and airway responsiveness to histamine (p<0.01). None of the parameters was significantly changed by placebo administration. CONCLUSIONS: These results suggest that RNS may be involved in the reversible component of inflammation in COPD that is suppressed by steroids. Further studies using specific inhibitors for RNS are needed to clarify their effects on the long term progression of COPD.     

Effect of regular inhaled salbutamol on airway responsiveness and airway inflammation in rhinitic non-asthmatic subjects

BACKGROUND: Regular, inhaled beta 2 agonists may increase airway responsiveness in asthmatic subjects. The mechanism is not known but may be via an increase in airway inflammation. A study was undertaken to examine the effect of regular inhaled salbutamol on airway responsiveness to methacholine and hypertonic saline, on the maximal response plateau to methacholine, and on inflammatory cells in induced sputum in rhinitic non-asthmatic subjects. METHODS: Thirty subjects with a baseline maximal response plateau of > 15% fall in forced expiratory volume in one second (FEV1) entered a randomised, placebo controlled, parallel trial consisting of two weeks run in, four weeks of treatment, and two weeks washout. Methacholine challenges were performed at the beginning of the run in period, before treatment, after treatment, and after washout. Hypertonic saline challenges were performed before and after treatment and induced sputum samples were collected for differential cell counting. RESULTS: There was no change in airway responsiveness, maximal response plateau to methacholine, or in induced sputum eosinophils or mast cells. The maximum fall in FEV1 after hypertonic saline increased in the salbutamol group (median change 6.0%, interquartile range (IQR) 11.0) but did not change in the placebo group (median change 1.3%, IQR 5.5). CONCLUSIONS: Regular inhaled salbutamol for four weeks increases airway responsiveness to hypertonic saline but does not alter airway responsiveness to methacholine or cells in induced sputum in non-asthmatic individuals with rhinitis. The relevance of these findings to asthmatic subjects has not been established.


     

Adrenal suppression with inhaled budesonide and fluticasone propionate given by large volume spacer to asthmatic children.

BACKGROUND: The aim of this study was to compare the systemic bioactivity of inhaled budesonide (B) and fluticasone propionate (F), each given by large volume spacer, on a microgram equivalent basis in asthmatic children. METHODS: Ten stable asthmatic children of mean age 11 years and forced expiratory volume in one second (FEV1) 81.6% predicted, who were receiving treatment with < or = 400 micrograms/day of inhaled corticosteroid, were studied in a placebo controlled single blind (investigator blind) randomised crossover design comparing single doses of inhaled budesonide and fluticasone propionate 400 micrograms, 800 micrograms, and 1250 micrograms. Doses were given at 20.00 hours with mouth rinsing and an overnight 12 hour urine sample was collected for estimation of free cortisol and creatinine excretion. RESULTS: The results of overnight 12 hour urinary cortisol output (nmol/12 hours) showed suppression with all doses of fluticasone propionate (as geometric means): F400 micrograms (11.99), F800 micrograms (6.49), F1250 micrograms (7.00) compared with placebo (24.43), whereas budesonide caused no suppression at any dose. A comparison of the drugs showed that there were differences at 800 micrograms and 1250 micrograms levels for urinary cortisol: B800 micrograms versus F800 micrograms (2.65-fold, 95% CI 1.26 to 5.58), B1250 micrograms versus F1250 micrograms (2.94-fold, 95% CI 1.67 to 5.15). The results for the cortisol/creatinine ratio were similar to that of urinary cortisol, with fluticasone causing suppression at all doses and with differences between the drugs at 800 micrograms and 1250 micrograms. CONCLUSIONS: Single doses of inhaled fluticasone produce greater systemic bioactivity than budesonide when given by large volume spacer on a microgram equivalent basis in asthmatic children. The systemic bioactivity of fluticasone, like budesonide, is due mainly to lung bioavailability.     

Analysis of induced sputum in adults with asthma: identification of subgroup with isolated sputum neutrophilia and poor response to inhaled corticosteroids

BACKGROUND: The debate as to whether asthma is a single or heterogeneous disease remains unresolved although pathological studies, mostly using fibreoptic bronchoscopy on small numbers of subjects, have emphasised the similarities between different clinical phenotypes. METHODS: Lower airway inflammation was assessed non-invasively using induced sputum in 34 normal controls and 259 adults with symptomatic asthma receiving treatment at steps 1-3 of the British Thoracic Society (BTS) guidelines. A subgroup of 49 patients treated with as required beta(2) agonists only who met BTS criteria for a step up in treatment were studied before and 2 months after treatment with inhaled budesonide 400 micro g twice daily. RESULTS: There was considerable heterogeneity in induced sputum cell counts, particularly in non-atopic patients. A subgroup of 60 patients had a distinctive sputum cell profile with a neutrophil count higher than our normal range (>65.3%) and a normal sputum eosinophil count (<1.9%). These patients were older, predominantly female, and were more likely to be non-atopic but otherwise had similar clinical and physiological features to the group as a whole. Among the 49 subjects studied before and after inhaled budesonide, 11 patients had an isolated sputum neutrophilia. Following treatment, these patients showed significantly less improvement in visual analogue symptom scores (-5.5 v -19.4 mm; mean difference 13.9; 95% CI 0.7 to 27.0), forced expiratory volume in 1 second (FEV(1)) (-0.08 v 0.13 l; mean difference 0.21; 95% CI 0.03 to 0.39), and concentration of methacholine provoking a fall in FEV(1) of 20% or more (PC(20)) (0.15 v 1.29 doubling doses; mean difference 1.11; 95% CI 0.13 to 2.15) than the remaining 38 patients. CONCLUSIONS: These results suggest the presence of a distinct subgroup of patients with mild to moderate asthma who have predominantly neutrophilic airway inflammation and who respond less well to treatment with inhaled corticosteroids.     

Markers of nitric oxide metabolism in sputum and exhaled air are not increased in chronic obstructive pulmonary disease

BACKGROUND: Nitric oxide (NO) is involved in inflammation and host defence of the lung. It has been found in increased concentrations in the airways in asthmatic subjects but its levels in patients with chronic obstructive pulmonary disease (COPD) have not been investigated. A study was undertaken to determine whether markers of NO metabolism (NO in exhaled air, iNOS expression in sputum cells, and nitrite + nitrate (NO2-/NO3-) in sputum supernatant) are increased in subjects with COPD, and whether they correlate with inflammatory indices in induced sputum. The associations of these markers with smoking were also assessed. METHODS: Sixteen subjects with COPD (median age 66 years, median forced expiratory volume in one second (FEV1) 63% predicted, eight current smokers) and 16 healthy subjects (median age 63 years, median FEV1 113% predicted, eight current smokers) participated in the study. NO was measured during tidal breathing and sputum was induced by inhalation of hypertonic saline. RESULTS: No differences were observed between subjects with COPD and healthy controls in exhaled NO excretion rate (median 5.15 and 6.25 nmol/min), sputum macrophage iNOS expression (14% and 12%), and sputum supernatant NO2-/NO3- (46 and 73 microM). NO in exhaled air correlated with the percentage of sputum eosinophils in patients with COPD (rho = 0.65, p = 0.009) but not in healthy individuals. Exhaled NO and supernatant NO2-/NO3- levels were lower in healthy smokers than in healthy non/ex-smokers. CONCLUSIONS: Our findings indicate that NO metabolism is not increased in patients with stable COPD. The close association between exhaled NO levels and sputum eosinophils suggests a role for NO in airway inflammation in COPD. Studies performed during exacerbations may clarify this role.     

Exhaled nitric oxide predicts asthma relapse in children with clinical asthma remission

BACKGROUND: Nitric oxide in exhaled air (FE(NO)) is a marker of eosinophilic airway inflammation. A study was undertaken to determine whether FE(NO) predicts asthma relapse in asymptomatic asthmatic children in whom inhaled corticosteroids are discontinued. METHODS: Forty children (21 boys) of mean age 12.2 years on a median dose of 400 mug budesonide or equivalent (range 100-400) were included. FE(NO) was measured before and 2, 4, 12, and 24 weeks after withdrawal of steroids. A relapse was defined as more than one exacerbation per month, or need for beta agonist treatment on 4 days per week for at least 2 weeks, or diurnal peak flow variability of >20%. FE(NO) measurements were performed online with an expiratory flow of 50 ml/s. RESULTS: Nine patients relapsed. Two and 4 weeks after withdrawal of steroids geometric mean FE(NO) in children who were about to relapse was higher than in those who did not relapse: 35.3 ppb v 15.7 ppb at 2 weeks (ratio 2.3; 95% CI 1.2 to 4.1; p = 0.01) and 40.8 ppb v 15.9 ppb at 4 weeks (ratio 2.6; 95% CI 1.3 to 5.1). An FE(NO) value of 49 ppb at 4 weeks after discontinuation of steroids had the best combination of sensitivity (71%) and specificity (93%) for asthma relapse. CONCLUSION: FE(NO) 2 and 4 weeks after discontinuation of steroids in asymptomatic asthmatic children may be an objective predictor of asthma relapse.     

Airway calibre as a confounder in interpreting bronchial responsiveness in asthma.

BACKGROUND: The relation between airway responsiveness to constrictor agents and forced expiratory volume in one second (FEV1) is important when interpreting change in airway responsiveness after an intervention. The aim of the study was to analyse the relation between FEV1 as a percentage of predicted values (% predicted) and airway responsiveness between and within asthmatic subjects. METHODS: Results of non-specific bronchial challenge tests were pooled from two randomised crossover studies comparing the effect of a non-sedative antihistamine with placebo in 35 patients with moderate asthma. The design of the two studies was similar: the provocative concentration of either histamine (first study) or methacholine (second study) resulting in a 20% decrease in ventilatory capacity (PC20) was repeated at two week intervals while patients were treated with the antihistamine or placebo. The dose of inhaled corticosteroid was gradually reduced during the study. Data were analysed with PC20 as the dependent variable in a general linear model so that the influence on PC20 of inhaled corticosteroid dose, antihistamine, and choice of bronchoconstricting agent could be separated from the influence of FEV1% predicted. RESULTS: The correlation coefficient between mean PC20 and mean prechallenge FEV1 for each patient was 0.45. In the general linear model two thirds (65%) of the variation in PC20 was due to variation between subjects. One third of the within subject variation in PC20 could be explained by variation in prechallenge FEV1% predicted (a change in FEV1 of 27% predicted was associated with one doubling or halving of PC20). Treatment with the antihistamine had no influence on PC20, except when histamine was used as the bronchoconstricting agent. The dose of inhaled corticosteroid had a small but significant effect. CONCLUSIONS: The variation in a patient's PC20 over time (several months) is related to changes in FEV1% predicted. Variation in FEV1% predicted explains less of the variation in bronchial responsiveness between subjects where a patient specific factor, which is probably related to the pathogenesis of bronchial asthma, seems to dominate.     

Dissociation between exhaled nitric oxide and hyperresponsiveness in children with mild intermittent asthma

BACKGROUND: Bronchial hyperresponsiveness and airway inflammation are distinctive features of asthma. Evaluation of nitric oxide (NO) levels in expired air have been proposed as a reliable method for assessing the airway inflammatory events in asthmatic subjects. A study was undertaken to evaluate whether airway hyperresponsiveness is related to levels of exhaled NO. METHODS: Thirty two steroid-naive atopic children with mild intermittent asthma of mean (SD) age 11.8 (2.3) years and 28 age matched healthy controls were studied to investigate whether baseline lung function or airway hyperresponsiveness is related to levels of exhaled NO. Airway responsiveness was assessed as the dose of methacholine causing a 20% decrease in forced expiratory volume in one second (FEV(1)) from control (PD(20) methacholine) and exhaled NO levels were measured by chemiluminescence analysis of exhaled air. RESULTS: At baseline asthmatic children had significantly higher NO levels than controls (mean difference 25.87 ppb (95% CI 18.91 to 32.83); p<0.0001) but there were no significant differences in lung function parameters (forced vital capacity (FVC), FEV(1) (% pred), and forced expiratory flows at 25-75% of vital capacity (FEF(25-75%))). In the asthmatic group exhaled NO levels were not significantly correlated with baseline lung function values or PD(20) methacholine. CONCLUSIONS: These results suggest that levels of exhaled NO are not accurate predictors of the degree of airway responsiveness to inhaled methacholine in children with mild intermittent asthma.