吸入性肾上腺糖皮质激素对咳嗽变异性哮喘呼吸道高反应性的影响

咳嗽变异性哮喘(cough variant asthma,CVA)是引起慢性咳嗽的最常见病因,约占其32%。1972年Glauser首次描述CVA,其唯一症状是慢性咳嗽,病理生理机制与支气管哮喘(简称哮喘)相似,以呼吸道炎症和呼吸道高反应性     

Furosemide plus albuterol compared with albuterol alone in children with acute asthma.

Several reports have shown that inhaled furosemide protects patients with asthma from different bronchoconstrictor agents. However, the effect of this widely used diuretic in acute exacerbation in adults is unproven. There are no reports of furosemide's therapeutic effect in acute asthma in children; thus, the objective of this study was to determine the effectiveness of the combined treatment of furosemide and albuterol in pediatric patients. Using a double-blind design, 20 emergency room patients with an asthmatic exacerbation were studied and randomly assigned to one of the following treatments: (1) furosemide + albuterol (1 and 0.15 mg/kg, respectively) or (2) albuterol (0.15 mg/kg). The forced expiratory volume in one second (FEV1) was measured in each patient before medication and then 30 and 60 minutes after inhalation of the individual drug or drug combination. Neither group differed in age or baseline FEV1. An increase in FEV1 of 22.8 +/- 4.3% (mean +/- SE) in the drug combination group was noted at 60 minutes, and an increase in FEV1 of 18.0 +/- 2.6% in the albuterol group was obtained at the same time. Although the increase in FEV1 was greater in the first group after 1 hour of treatment, this was not significant. These results suggest that inhaled furosemide does not have a synergistic effect with albuterol in the treatment of asthmatic exacerbations in children.     

Effect of mild hypoxia on airway responsiveness to methacholine in subjects with airway hyperresponsiveness

STUDY OBJECTIVES: The inhalation of hypoxic gas has been reported to enhance the airway responsiveness to methacholine in some animal models. However, the data on humans have so far been conflicting. We attempted to examine the effect of hypoxic gas inhalation on the airway responsiveness to methacholine. DESIGN: We evaluated the airway responsiveness to methacholine by continuously measuring respiratory conductance with the forced oscillation method under normoxia or hypoxia in a single-blind, randomized, crossover fashion (2 days for each). PARTICIPANTS: Twelve asymptomatic male volunteers (mean +/- SD age, 27 +/- 4 years) with airway hyperresponsiveness to methacholine. Two of the 12 volunteers had a history of bronchial asthma. SETTING: The participants inhaled either normoxic or hypoxic gas with continuous inhalation of aerosolized methacholine in incremental doses with a sustained respiratory rate of 15 breaths/min. The arterial oxygen saturation was kept to 90% on the hypoxic days. RESULTS: There were no significant differences in any indexes of airway responsiveness to methacholine (the cumulative dose of methacholine at the threshold and the point of 35% decrease of the respiratory conductance, and the slope factor of the dose-response curve) between the hypoxic days and the normoxic days. CONCLUSION: The inhalation of mildly hypoxic gas does not enhance the airway responsiveness to methacholine in humans with airway hyperresponsiveness.     

Asymptomatic airway hyperresponsiveness: relationships with airway inflammation and remodelling.

To study the physiopathology and significance of asymptomatic airway hyperresponsiveness (AHR), the clinical and bronchial immunohistological parameters were evaluated in subjects with asymptomatic and symptomatic AHR. Asymptomatic subjects with AHR (eight females/two males, no respiratory symptoms, provocative concentration of methacholine causing a 20% fall in forced expiratory volume in one second (PC20) <8 mg x mL(-1) and no treatment) were compared with asthmatic subjects paired for age, sex and PC20, and with nonatopic, nonasthmatic controls paired for age and sex. All three groups were evaluated once at baseline, whilst the asymptomatic AHR subjects were re-evaluated after 1 and 2 yrs. Measurements included spirometry, methacholine challenge, serum immunoglobulin (Ig)E, blood eosinophils, and bronchoscopy (at baseline and after 2 yrs only). At first evaluation, the mean blood eosinophil count, total serum IgE level, atopic index, baseline forced expiratory volume in one second (FEV1) and the degree of bronchial epithelial desquamation of the asymptomatic AHR subjects were similar to those of asthmatic subjects. However, they presented focal rather than the continuous bronchial subepithelial fibrosis observed in asthmatics. Their mucosal CD3, CD4, CD25, EG1 and EG2-positive cell counts were intermediate between those of the control subjects and asthmatics. At the end of the 2-yr follow-up, four of them had developed asthma symptoms. At this time, bronchial biopsies revealed an increase in the extent of subepithelial fibrosis and in the number of CD25 and CD4-positive cells, and a decrease in the number of CD8+ cells, particularly in subjects who developed asthma symptoms. These data suggest that asymptomatic airway hyperresponsiveness is associated with airway inflammation and remodelling, and that the appearance of asthma symptoms is associated with an increase in these features, particularly the CD4/CD8 ratio and airway fibrosis. Consequently, this study proposes an association between asymptomatic airway hyperresponsiveness and airway inflammation, structural changes and asthma although these relationships remain to be further evaluated.     

Effect of long-term treatment with an inhaled corticosteroid (budesonide) on airway hyperresponsiveness and clinical asthma in nonsteroid-dependent asthmatics

Several short-term studies have shown that inhaled steroids can reduce airway hyper-responsiveness in asthma. To evaluate whether prolonged treatment can bring about full recovery, this double-blind, randomized, controlled trial examined the effect of budesonide, 400 micrograms daily for 1 yr, on airway hyperresponsiveness. The time course and characteristics of improvements and associated changes in clinical asthma severity were also evaluated. Thirty-two stable adult asthmatics, requiring bronchodilators alone, were selected. Before and monthly throughout the study, airway responsiveness to methacholine was measured and clinical asthma severity assessed by questionnaire, daily bronchodilator use, and number of asthma exacerbations. Patients receiving budesonide showed a fourfold mean improvement in airway responsiveness compared with those receiving placebo (p less than 0.0005), whose responsiveness remained very stable. Fifteen of the 16 budesonide subjects improved and 5 returned to the normal range. Largest improvements occurred during the first 3 months but, in some, were still progressing slowly at 1 yr. Improvements in responsiveness were accompanied by significant improvements in asthma symptoms, bronchodilator use, and number of asthma exacerbations. The results show that regular, prolonged use of inhaled steroid can produce marked improvements in airway hyperresponsiveness, sometimes with full resolution, and these improvements are accompanied by clinically significant improvements in clinical asthma.     

Safety of long-term treatment with HFA albuterol

BACKGROUND: Chlorofluorocarbons (CFCs) used as propellants in metered-dose inhalers deplete stratospheric ozone, which results in serious public health concerns. Albuterol has been reformulated in the non-ozone-depleting propellant, hydrofluoroalkane-134a (HFA albuterol). OBJECTIVES: The primary objective was to compare the safety of HFA albuterol to an albuterol product formulated in chlorofluorocarbon propellants (CFC albuterol) during 1 year of treatment in asthmatics. Bronchodilator efficacy of the two products was assessed as a secondary objective. METHODS: The results from two open-label, parallel-group trials of similar design in asthmatics requiring short-acting beta-agonists for symptom control were combined. Patients took two puffs bid of either HFA albuterol or CFC albuterol for 1 year. Additional puffs of study drug were allowed as needed to control asthma symptoms. Adverse events were recorded at clinic visits. Patients self-administered study drug at quarterly visits and underwent serial spirometry during a 6-h period postdose. Bronchodilator efficacy variables, based on FEV1 response to study drug, were proportion of responders, time to onset of effect, peak percent change, time to peak effect, duration of effect, and area under the curve. Differences between products and changes over time in efficacy variables were assessed using an analysis of variance model. Regression analyses with FEV1 as a covariate were performed post-hoc to analyze changes in bronchodilator efficacy over time. RESULTS: Demographic and baseline characteristics were similar for patients receiving HFA albuterol (n = 337) and CFC albuterol (n = 132). Total reported adverse events were similar for the two treatments. Differences in only four individual adverse events were noted: the HFA albuterol group reported more gastroenteritis and dizziness; the CFC albuterol group reported more epistaxis and expectoration. Adverse events attributed to study drug use were infrequent. No serious adverse events were related to study drug use. Predose FEV1 at quarterly visits increased to a small extent in both groups from month 0 to month 12. The bronchodilator efficacy of HFA albuterol was comparable to that of CFC albuterol at the quarterly visits, but decreased from baseline for both products over the 12 months of treatment. Use of inhaled corticosteroids, nasal corticosteroids, or theophylline did not explain the increase in predose FEV1 over time and did not protect patients from developing reduced bronchodilator efficacy by month 12. The change in predose FEV1 did not entirely account for the reduced bronchodilator efficacy over time. CONCLUSIONS: HFA albuterol has a safety profile similar to that of CFC albuterol during chronic, scheduled use, and both drugs are well tolerated. HFA albuterol and CFC albuterol provided comparable bronchodilator efficacy, but bronchodilator efficacy decreased for both products with 1 year of use.     

Assessing the effects of racemic and single-enantiomer albuterol on airway secretions in long-term intubated patients

OBJECTIVE: In vitro data suggest that the S-enantiomer of albuterol can induce mucociliary dysfunction. This clinical study assesses the clinical significance of standard doses of the S-enantiomer on airway secretions in long-term intubated patients by comparing a racemic formulation of albuterol, an R-enantiomer formulation, and normal saline solution. DESIGN: A placebo-controlled crossover study. PATIENTS: Fourteen stable intubated patients with a median duration of intubation of 21 months and a median age of 72 years. SETTING: Long-term ventilator unit in skilled nursing facility. INTERVENTIONS: Following a 2-week washout period during which regularly scheduled beta2-agonists were discontinued, tracheal aspirates were collected for 4 h/d for a 5-day period to establish baseline values, and the patients were then randomized in crossover manner to each of three nebulized treatments: normal saline solution, racemic albuterol, and R-albuterol. Each treatment was administered three times daily for 5 days, followed by a 2-day washout. MEASUREMENTS: Tracheal aspirates were analyzed for volume, sodium, chloride, bicarbonate, interleukin (IL)-8, IL-1beta, soluble intercellular adhesion molecule, and tumor necrosis factor-alpha. RESULTS: There were no consistent significant differences among the three treatment periods either in terms of volume of secretions or in the concentrations of the electrolytes or the inflammatory indexes. However, all three treatments, including saline solution, were associated with increased secretion volume after the first dose, but this effect was not apparent on subsequent doses. CONCLUSION: There were no significant differences between racemic albuterol and R-albuterol observed in this study for any of the parameters studied, suggesting that the S-enantiomer does not adversely affect airway secretions at recommended doses. In addition, the routine administration of nebulized beta(2)-sympathomimetic agonists to stable patients undergoing prolonged intubation, for the sole purpose of changing the volume and composition of secretions of airway secretions, is not supported by the results of this study.     

Markers of airway inflammation and airway hyperresponsiveness in patients with well-controlled asthma.

In steroid-naive asthmatics, airway hyperresponsiveness correlates with noninvasive markers of airway inflammation. Whether this is also true in steroid-treated asthmatics, is unknown. In 31 stable asthmatics (mean age 45.4 yrs, range 22-69; 17 females) taking a median dose of 1,000 microg inhaled corticosteroids (ICS) per day (range 100-3,600 microg x day(-1)), airway responsiveness to the "direct" agent histamine and to the "indirect" agent mannitol, lung function (forced expiratory volume in one second (FEV1), forced vital capacity (FVC), peak expiratory flow (PEF)), exhaled nitric oxide (eNO), and number of inflammatory cells in induced sputum as a percentage of total cell count were measured. Of the 31 subjects, 16 were hyperresponsive to mannitol and 11 to histamine. The dose-response ratio (DRR: % fall in FEV1/cumulative dose) to both challenge tests was correlated (r=0.59, p=0.0004). However, DRR for histamine and DRR for mannitol were not related to basic lung function, eNO, per cent sputum eosinophils and ICS dose. In addition, NO was not related to basic lung function and per cent sputum eosinophils. In clinically well-controlled asthmatics taking inhaled corticosteroids, there is no relationship between markers of airway inflammation (such as exhaled nitric oxide and sputum eosinophils) and airway responsiveness to either direct (histamine) or indirect (mannitol) challenge. Airway hyperresponsiveness in clinically well-controlled asthmatics appears to be independent of eosinophilic airway inflammation.     

Effect of combining salmeterol and fluticasone on the progression of airway remodeling

In subjects insufficiently controlled with low to moderate doses of inhaled corticosteroids, adding beta-agonists is clinically more beneficial than increasing the dose of inhaled corticosteroids. In the present study, we investigated the effect of adding salmeterol to fluticasone on allergen-induced airway inflammation and remodeling. Sensitized rats, in which characteristics of remodeling had been induced by ovalbumin exposure every 2 days from Days 14 to 28, were further exposed to ovalbumin or PBS from Days 29 to 42. During the last 2 weeks, before allergen exposure, rats were treated with aerosolized fluticasone propionate (10 mg), salmeterol (1 mg), salmeterol (1 mg) plus fluticasone propionate (10 mg), or placebo. After 4 weeks of ovalbumin exposure, the airways showed inflammatory changes, goblet cell hyperplasia, and enhanced fibronectin and collagen deposition. Salmeterol in monotherapy decreased bronchoalveolar lavage fluid eosinophil number but had no influence on structural changes. Combining salmeterol with fluticasone propionate counteracted goblet cell hyperplasia, but increased the amount of fibronectin and collagen in the airway wall. These effects of salmeterol did not influence airway responsiveness. We conclude that the combination of salmeterol and fluticasone propionate enhances aspects of allergen-induced airway remodeling. This is not accompanied by changes in airway responsiveness.     

Effect of long-term treatment with sodium cromoglycate on nonspecific bronchial hyperresponsiveness in asthma

Several studies in the past have demonstrated a reduction in nonspecific bronchial hyperresponsiveness subjects with seasonal extrinsic asthma after long-term treatment with sodium cromoglycate. Since sodium cromoglycate is an effective drug in the prophylactic treatment of all types of asthma, we assessed the effect of a three-month treatment on nonspecific bronchial hyperresponsiveness in 11 patients with perennial asthma. Bronchial responsiveness was determined by histamine bronchoprovocation test, using SGaw as the index of lung function and expressed as PD35SGaw. During the run-in period of one month when sodium cromoglycate was not used, the histamine PD35SGaw decreased significantly from 0.15 +/- 0.30 to 0.09 +/- 0.29 mg/ml (p less than 0.001). After three months of treatment with the drug, bronchial hyperresponsiveness was reduced significantly; the PD35SGaw was 0.21 +/- 0.29 mg/ml (p less than 0.001). It was concluded that long-term treatment of patients with perennial asthma with sodium cromoglycate results in reduced bronchial hyperresponsiveness.     

Effects of salmeterol on arterial blood gases in patients with stable chronic obstructive pulmonary disease. Comparison with albuterol and ipratropium.

Administration of beta-adrenergic agonist bronchodilators to patients with airways obstruction commonly results in transient decreases in Pa(O(2)) levels despite bronchodilation, an effect that has been attributed to these drugs' pulmonary vasodilator action. We compared the acute effects on gas exchange of salmeterol with those of albuterol and the anticholinergic agent ipratropium in 20 patients with stable chronic obstructive pulmonary disease (COPD). Each agent was given in recommended dosage on separate days in a double-blind, crossover format, and the patients' arterial blood gases (ABGs) were measured at baseline and at intervals to 120 min. Small but statistically significant declines in Pa(O(2)), the primary outcome variable, were found after administration of both salmeterol and albuterol. The decline in PaO2 after salmeterol was of lesser magnitude but was more prolonged than that after albuterol, the greatest mean change being -2.74 +/- 0.89 mm Hg (mean +/- SEM) at 30 min after salmeterol, and -3.45 +/- 0.92 mm Hg at 20 min after albuterol. Following ipratropium, the corresponding change was -1.32 +/- 0.85 mm Hg at 20 min. These declines, which were almost entirely attributable to increases in the alveolar-arterial difference in oxygen tension Delta(A-a)DO2 tended to be more marked in subjects with higher baseline PaO2 values. No subject experienced a decline in PaO2 to levels below 59 mm Hg. There were no significant differences among the three drugs studied. We conclude that despite small decreases in PaO2 after each of the three drugs, the declines were small transient, and of doubtful clinical significance.     

钙池操纵性钙通道抑制剂SKF96365对慢性哮喘小鼠气道重塑和气道高反应性的作用

目的:观察钙池操纵性钙通道抑制剂SKF96365对小鼠慢性哮喘模型气道重塑和气道高反应性的影响。方法:用鸡卵清白蛋白(OVA)致敏和激发小鼠,建立慢性哮喘模型,33只雌性BALB/c小鼠随机分为3组:对照组、哮喘组、SKF96365组,每组11只,其中SKF96365组于每次激发前30 min给予SKF96365(10mg/kg)干预。哮喘组和SKF96365组于第0、7、14 d腹腔注射(i.p)200μL致敏液(含OVA粉剂20μg、氢氧化铝凝胶2 mg);自第21天起,腹腔注射1%戊巴比妥钠(70mg戊巴比妥钠/kg小鼠体重)麻醉小鼠后,OVA(40μg)滴鼻(i.n),连续6周,每周3次,共18次。对照组则在相同时间给予相应剂量的生理盐水腹腔注射和滴鼻。最后一次激发后24 h,各组分别随机取5只小鼠用于检测组织病理学变化,另6只小鼠采用Buxco小动物肺功能仪检测气道高反应性。其中组织病理学检测计算杯状细胞(过碘酸希夫染色阳性,PAS+)、胶原细胞(Masson阳性)和平滑肌细胞(α-SMA阳性)阳染面积/支气管基底膜周长值来评估小鼠气道重塑;观察给予不同浓度乙酰甲胆碱雾化时的气道阻力(resistance index,RI)最大值,评估小鼠气道高反应性。结果:对照组未见PAS阳性染色区域,哮喘组和SKF96365组杯状细胞增生高于对照组(7.29±2.04,4.49±1.70 vs 0.00±0.00,均P0.01),且SKF96365组低于哮喘组(P0.05)。Masson染色显示哮喘组和SKF96365组上皮下胶原沉积高于对照组(9.23±1.41,7.30±1.33 vs 1.60±0.77,均P0.01),且SKF96365组低于哮喘组(P0.05)。α-SMA免疫组化显示哮喘组和SKF96365组平滑肌增生肥大高于对照组(4.54±1.05,3.15±0.57 vs 1.97±0.69,均P0.05),且SKF96365组低于哮喘组(P0.05)。当乙酰甲胆碱(Mch)≤6.25 mg/m L时,3组小鼠气道阻力无显著差异(P0.05),当25 mg/m LMch≥12.25 mg/m L时,哮喘组小鼠气道阻力明显大于对照组小鼠(P0.001),当Mch≥25 mg/m L时,哮喘组小鼠气道阻力大于SKF96365组(P0.05)。结论:采用SKF96365干预后,慢性哮喘小鼠气道重塑和气道高反应性指标均有改善,提示SKF96365可能对哮喘气道重塑和气道高反应性具有抑制作用。     

Association of MS Pi phenotype with airway hyperresponsiveness

Asthmatic families (AFs) and normal families (NFs) were studied to determine the relationship between bronchial hyperresponsiveness and alpha 1-antitrypsin protease inhibitor phenotype. We studied IgE levels, skin test scores, and methacholine sensitivity. In both the AF and NF groups, the subjects with the MS phenotype had significantly greater methacholine-induced bronchial hyperresponsiveness sensitivity than the MM and MZ subjects. These findings suggest that the S allele may be associated with bronchial hyperresponsiveness.     

Sputum eosinophilia, airway hyperresponsiveness and airway narrowing in young adults with former asthma.

Background: 30-80% of outgrown asthma subjects develop symptoms again later in life. We investigated inflammation and function of lower airway in adolescents with former asthma. Methods: 326 never-smoking young adults (mean age 24.0 years) were interviewed with special emphasis on history of asthma. Diagnosis of asthma was based on GINA guidelines. Former asthma subjects consisted of ones with a history of physician-diagnosed childhood asthma, who had been free of asthma symptoms without the use of medication for at least 10 years prior to the study. Provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 second (FEV(1))(PC(20)) and eosinophil percentage in induced sputum were measured. Results: 31 subjects were former asthma subjects (FBA), 11 subjects were current asthma subjects (CBA) and 284 subjects had no history of asthma (non-BA). PC(20) and FEV(1)/FVC ratio were significantly lower in the FBA group than in the non-BA group (P < 0.01). Maximal mid-expiratory flow (MMF) was significantly lower in the FBA group than in the non-BA group (P < 0.05). Sputum eosinophil percentage was significantly increased in the FBA group compared with the non-BA group (P < 0.01). PC(20) was significantly lower in the CBA group than in the FBA and non-BA groups (P < 0.01). FEV(1), FEV(1)/FVC ratio and MMF were significantly lower in the CBA group than in the FBA group (P < 0.05, P < 0.05 and P < 0.05, respectively) and the non-BA group (P < 0.01, P < 0.01 and P < 0.05, respectively). Sputum eosinophils were significantly higher in the CBA group than in the FBA and non-BA groups (P < 0.01). Conclusions: This study shows that subjects with long-term outgrown asthma continue to have airway eosinophilic inflammation, airway hyperresponsiveness and airway narrowing.