The effect of inhaled corticosteroids on the maximal degree of airway narrowing to methacholine in asthmatic subjects

Budesonide Attains Its Wide Clinical Profile by Alternative Kinetics

The introduction of inhaled corticosteroids (ICSs) changed over a few decades the treatment focus of mild-to-moderate asthma from bronchodilation to reduction in inflammation. This was achieved by inhaling a suitable corticosteroid (CS), giving a high, protracted airway concentration at a low total dose, thereby better combining efficacy and tolerance than oral therapy. Successful trials with the potent, lipophilic "skin" CS beclomethasone dipropionate (BDP) paved the way, suggesting that ICSs require a very low water solubility, prolonging their intraluminal dissolution within airways. The subsequent ICS development, with resulting clinical landmarks, is exemplified here with budesonide (BUD), showing that a similar efficacy/safety relationship is achievable by partly alternative mechanisms. BUD is much less lipophilic, giving it a 100-fold higher water solubility than BDP and later developed ICSs, leading to its more rapid intraluminal dissolution and faster airway and systemic uptake rates. In airway tissue, a BUD fraction is reversibly esterified to intracellular fatty acids, a lipophilic conjugate, which prolongs airway efficacy. Another mechanism is that the rapidly absorbed bulk fraction, via short plasma peaks, adds anti-inflammatory activity at the blood and bone marrow levels. Importantly, these plasma peaks are too short to provoke systemic adverse actions. Controlled clinical trials with BUD changed the use of ICS from a last resort to first-line treatment. Starting ICS treatment immediately after diagnosis ("early intervention") became a landmark for BUD. An established dose response made BUD suitable for the treatment of patients with all degrees of asthma severity. With the development of the budesonide/formoterol combination inhaler (BUD/FORM), BUD contributed to the widely used BUD/FORM maintenance and reliever therapy (MART). Recent studies demonstrated the value of BUD/FORM as a generally recommended as-needed therapy for asthma ("anti-inflammatory reliever", AIR). These abovementioned qualities have all influenced international asthma management and treatment guidelines.

Eosinophil Inflammation and Hyperresponsiveness in the Airways as Phenotypes of COPD, and Usefulness of Inhaled Glucocorticosteroids

Background: The differential diagnosis in persistent airway limitation is sometimes not so clear in older adults. Airway eosinophilia and airway hyperresponsiveness may develop in some cases with chronic obstructive lung disease (COPD), independent of asthma. However, little is known about clinical significance of these phenotypes of COPD in detail. Aims and objectives: This clinical study was designed to examine prevalence of airway eosinophilia and airway hyperresponsiveness in COPD who have no symptom and no past history of asthma, and to examine involvement of these pathophysiological features of asthma in the management and therapy for COPD. Methods: Sputum examination via qualitative and quantitative procedures was performed in stable COPD (GOLD 1-3). When sputum eosinophils were qualitatively (≥+) or quantitatively assessed (≥3%), ciclesonide (inhaled glucocorticosteroids) was added on bronchodilators. In cases with FEV₁ ≥ 70% of predicted values, acetylcholine provocation test was examined for assessment of airway hyperresponsiveness. Therapeutic effect was evaluated using spirometry and COPD assessment test (CAT). Results: Sputum eosinophils were observed in 65 (50.4%) of 129 subjects using qualitative analysis; in contrast, lower grade (>0%) and higher grade (≥3%) were observed in 15 (20.3%) and 25 (33.8%) of 74 subjects using quantitative analysis. Airway hyperresponsiveness developed in 46.9% of these subjects with sputum eosinophils. Exacerbations occurred much more frequently in lower-grade airway eosinophilia without ciclesonide than in higher-grade airway eosinophilia with ciclesonide. Airway hyperresponsiveness significantly increased frequency of exacerbations in COPD with both lower and higher grade in airway eosinophilia. Addition of ciclesonide to indacaterol markedly improved lung function (FEV₁, IC), CAT score, and reliever use in these subjects with airway eosinophilia determined by qualitative analysis. However, ciclesonide was less effective in improving these values in subjects with airway hyperresponsiveness than in those without airway hyperresponsiveness. Conclusions: Airway eosinophilia and airway hyperresponsiveness are complicated with 25-50% of COPD that have no symptom and history for asthma. These phenotypes of COPD are closely related to symptom stability and reactivity to glucocorticosteroids. These phenotypes may play key roles for advancement of the management and therapy of this disease.

Repurposing drugs as inhaled therapies in asthma

For the first 40 years of the 20th century treatment for asthma occurred in response to an asthma attack. The treatments were given by injection or orally and included the adrenergic agonists adrenalin/epinephrine and ephedrine and a phosphodiesterase inhibitor theophylline. Epinephrine became available as an aerosol in 1930. After 1945, isoprenaline, a non-selective beta agonist, became available for oral use but it was most widely used by inhalation. Isoprenaline was short-acting with unwanted cardiac effects. More selective beta agonists, with a longer duration of action and fewer side-effects became available, including orciprenaline in 1967, salbutamol in 1969 and terbutaline in 1970. The inhaled steroid beclomethasone was available by 1972 and budesonide by 1982. Spirometry alone and in response to exercise was used to assess efficacy and duration of action of these drugs for the acute benefits of beta₂ agonists and the chronic benefits of corticosteroids. Early studies comparing oral and aerosol beta₂ agonists found equivalence in bronchodilator effect but the aerosol treatment was superior in preventing exercise-induced bronchoconstriction. Inhaled drugs are now widely used including the long-acting beta₂ agonists, salmeterol and formoterol, and the corticosteroids, fluticasone, ciclesonide, mometasone and triamcinolone, that act locally and have low systemic bio-availability. Repurposing drugs as inhaled therapies permitted direct delivery of low doses of drug to the site of action reducing the incidence of unwanted side-effects and permitting the prophylactic treatment of asthma.

Bronchoprotective effect of vilanterol against methacholine-induced bronchoconstriction in mild asthmatics: A randomized three-way crossover study

BACKGROUND

Ultra-long-acting β2 agonists (uLABA) are relatively new anti-asthma medications of which there are three different formulations currently available: olodaterol, indacaterol, and vilanterol. The first 2 formulations have been shown to exert bronchoprotective effects; they are able to prevent airway smooth muscle contraction on exposure to constricting stimuli. However, studies have found that these 2 drugs produce different degrees and durations of bronchoprotection against methacholine.

OBJECTIVE

The objective of this study was to investigate the degree of bronchoprotection provided by vilanterol against methacholine-induced bronchoconstriction.

METHODS

Fourteen patients with mild-to-moderate asthma (8 male; baseline percent predicted forced expiratory volume in 1 second [FEV₁] > 65%; provocative concentration of methacholine causing a 20% reduction in FEV₁ [PC20] ≤ 8 mg/mL) completed this randomized, double-blind, 3-way crossover study. Methacholine challenges were performed before treatment administration (placebo, 100 μg fluticasone furoate, or 25 μg vilanterol + 100 μg fluticasone furoate) and at 0.5 and 24 hours posttreatment. Each treatment arm was separated by a minimum 7-day washout period. A combination therapy of vilanterol+fluticasone furoate was used, because vilanterol is not available as a monotherapy.

RESULTS

Significant bronchoprotection was evident after the combination treatment at both 0.5 and 24 hours with doubling dose shifts in methacholine PC20 of 2.0 (P = .0004) and 1.6 (P = .0001), respectively. Clinically significant bronchodilation was only recorded at 24 hours after combination treatment (P < .05).

CONCLUSION

These findings suggest that vilanterol (in combination with fluticasone furoate) provides significant bronchoprotection against methacholine-induced bronchoconstriction for at least 24 hours in patients with mild-to-moderate asthma.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov (NCT03315000).

Methacholine challenge testing: comparative pharmacology

Standardization of the methacholine inhalation challenge, the most common direct bronchoprovocation test, is important. One aspect of standardization is the appropriate washout period for pharmacologic agents which affect the response. This review summarizes the available data on pharmacologic inhibition of the methacholine response. Specific (anti-muscarinic) agents demonstrate marked bronchoprotection (up to 7 days for the long-acting drugs) which lasts longer than the duration of bronchodilation. The functional antagonist (beta 2 agonist class of medications) shows marked, but less, bronchoprotection which is relatively short lived and is similar to the duration of bronchodilator efficacy. Tolerance develops quickly, especially to the long-acting agents. Single doses of controller medications, such as inhaled corticosteroids (ICS) and leukotriene receptor antagonists, have no effect on the methacholine test, while regular use, at least for ICS, has a modest protective effect whose duration is uncertain and likely variable. Theophylline has a small effect and H1 blockers (all generations) have a negligible effect.

The effect of glycopyrronium and indacaterol, as monotherapy and in combination, on the methacholine dose-response curve of mild asthmatics: a randomized three-way crossover study

BACKGROUND

Methacholine dose-response curves illustrate pharmacologic bronchoprotection against methacholine-induced airway hyperresponsiveness and can be used to quantitate changes in airway sensitivity (position), reactivity (slope), and maximal responsiveness following drug administration. Our objective was to determine the influence of single-dose glycopyrronium (long-acting muscarinic antagonist) and indacaterol (ultra-long acting β₂ agonist), as monotherapy and in combination, on the methacholine dose-response curve of mild asthmatics and to compare these findings with a non-asthmatic control curve.

METHODS

This was a randomized, double blind, double dummy, three-way crossover study. For asthmatic participants (n = 14), each treatment arm included a baseline methacholine challenge, drug administration, and repeat methacholine challenges at 1, 24, and 48 h. Non-asthmatic control participants (n = 15) underwent a single methacholine challenge and did not receive any study treatment. Methacholine dose-response curves were graphed as the percent fall in forced expiratory volume in 1 s (FEV₁) for each methacholine concentration administered. Best-fit curves were then generated. Differences in airway reactivity were calculated through linear regression. Changes in airway sensitivity were assessed as the shift in the provocative concentration of methacholine causing a 20% fall in FEV₁.

RESULTS

Compared to baseline, all treatments significantly reduced airway sensitivity to methacholine at 1 h post-dose (indacaterol ~1.5 doubling concentrations; glycopyrronium ~5 doubling concentrations; combination ~5 doubling concentrations). Bronchoprotection at 24 and 48 h remained significant with glycopyrronium and combination therapy only. Airway reactivity was not influenced by indacaterol whereas glycopyrronium significantly reduced airway reactivity at all time-points (p = 0.003-0.027). The combination significantly decreased slope at 1 (p = 0.021) and 24 (p = 0.039) hours only. The non-asthmatic control and 1-h glycopyrronium curves are nearly identical. Only the non-asthmatic control and 1-h post-combination therapy curves appeared to generate a true response plateau (three data points within 5%), which occurred at a 14% fall in FEV₁.

CONCLUSIONS

Methacholine dose-response curves differentiate the bronchoprotective mechanisms triggered by different classes of asthma medications. Assessment of bronchoprotection using methacholine dose-response curves may be useful during clinical development of respiratory medications when performing superiority, equivalence, or non-inferiority trials.

TRIAL REGISTRATION

clinicaltrials.gov ( NCT02953041 ). Retrospectively registered on October 24th 2016.

Xanthines and Phosphodiesterase Inhibitors

Theophylline is an orally acting xanthine that has been used since 1937 for the treatment of respiratory diseases including asthma and chronic obstructive pulmonary disease (COPD). However, in most treatment guidelines, xanthines have now been consigned to third-line therapy because of their narrow therapeutic window and propensity for drug-drug interactions. However, lower than conventional doses of theophylline considered to be bronchodilator are now known to have anti-inflammatory actions of relevance to the treatment of respiratory disease. The molecular mechanism(s) of action of theophylline are not well understood, but several potential targets have been suggested including non-selective inhibition of phosphodiesterases (PDE), inhibition of phosphoinositide 3-kinase, adenosine receptor antagonism and increased activity of certain histone deacetylases. Although theophylline has a narrow therapeutic window, other xanthines are in clinical use that are claimed to have a better tolerability such as doxofylline and bamifylline. Nonetheless, xanthines still play an important role in the treatment of asthma and COPD as they can show clinical benefit in patients who are refractory to glucocorticosteroid therapy, and withdrawal of xanthines from patients causes worsening of disease, even in patients taking concomitant glucocorticosteroids.More recently the orally active selective PDE4 inhibitor, roflumilast, has been introduced into clinical practice for the treatment of severe COPD on top of gold standard treatment. This drug has been shown to improve lung function in patients with severe COPD and to reduce exacerbations, but is dose limited by a range side effect, particularly gastrointestinal side effects.

Therapeutic novelties of inhaled corticosteroids and bronchodilators in asthma

Orally inhaled agents are a key therapeutic class for treatment of asthma. Inhaled corticosteroids (ICS) are the most effective anti-inflammatory treatment for asthma thus representing the first-line therapy and bronchodilators complement the effects of ICSs. A significant body of evidence indicates that addition of a β2-agonist to ICS therapy is more effective than increasing the dose of ICS monotherapy. In this paper, pharmacological features of available ICSs and bronchodilators will be reviewed with a focus on fluticasone propionate/formoterol fumarate combination which represents the one of the most powerful ICS acting together with the most rapid active LABA.

Past, present and future uses of methacholine testing

Methacholine challenge testing is a valuable diagnostic and research tool used by clinicians to assist in the diagnosis of asthma, and by researchers to understand disease pathophysiology and assess novel therapeutic efficacy. The use of methacholine challenge in asthma relates to its direct effect on airway smooth muscle (i.e., bronchoconstriction) as a measure of airway hyperresponsiveness, a cardinal feature of asthma. Airway hyperresponsiveness has been documented in other airway disorders, including chronic obstructive pulmonary disease, cystic fibrosis and allergic rhinitis; however, there is little clinical application of methacholine challenge in these conditions as a diagnostic or disease management tool. The authors will review the aspects of methacholine challenge testing, as they relate to asthma, and point out its usefulness in clinical research. A brief review of past (historical) uses and speculation as to the future uses of methacholine challenge will also be discussed.

Effects of fluticasone propionate on arachidonic acid metabolites in BAL-fluid and methacholine dose-response curves in non-smoking atopic asthmatics

Hyperresponsiveness of the airways to nonspecific stimuli is a characteristic feature of asthma. Airway responsiveness is usually characterized in terms of the position and shape of the dose–response curve to methacholine (MDR). In the study we have investigated the influence of fluticasone propionate (FP), a topically active glucocorticoid, on arachidonic acid (AA) metabolites in broncho-alveolar lavage (BAL) fluid (i.e. TxB₂, PGE₂, PGD₂, 6kPGF_1α and LTC₄) on the one hand and MDR curves on the other hand. The effect of FP was studied in a randomized, double-blind, placebo-controlled design in 33 stable nonsmoking asthmatics; 16 patients received FP (500 μg b.i.d.) whereas 17 patients were treated with placebo. We found that the forced expiratory volume in 1s (FEV₁ % predicted) increased, the log₂PC₂₀ methacholine increased and the plateau value (% fall in FEV₁) decreased after a 12 week treatment period. No changes in AA-metabolites could be determined after treatment except for PGD₂ which decreased nearly significantly (p = 0.058) within the FP treated group, whereas the change of PGD₂ differed significantly (p = 0.05) in the FP treated group from placebo. The levels of the other AA metabolites (i.e. TxB₂, PGE₂, 6kPGF_1α and LTC₄) remained unchanged after treatment and were not significantly different from the placebo group. Our results support the hypothesis that although FP strongly influences the position, the shape and also the maximum response plateau of the MDR curve, this effect is not mainly achieved by influence on the level of AA metabolites. Other pro-inflammatory factors may be of more importance for the shape of the MDR curve. It is suggested that these pro-inflammatory factors are downregulated by FP.

Natural pollen exposure increases the response plateau to adenosine 5'-monophosphate and bronchial but not alveolar nitric oxide in sensitized subjects

BACKGROUND

The effect of allergen exposure on airway responsiveness and exhaled nitric oxide (NO) has been well documented, but no information is available on allergen-induced changes in the response plateau to adenosine 5'-monophosphate (AMP) and in bronchial NO flux (J'aw(NO)) and alveolar NO (CA(NO)).

OBJECTIVES

To determine the effect of natural allergen exposure, a proinflammatory stimulus, on the shape of the concentration-response curve to AMP and NO production in airway and alveolar sites.

METHODS

Airway responsiveness to high concentrations of methacholine and AMP, J'aw(NO) and CA(NO) values were obtained in 31 subjects with pollen allergy and in 11 healthy controls. Subjects with pollen allergy were studied before and at the height of the pollen season whereas healthy controls were tested on one occasion only.

RESULTS

In the group with pollen allergy, natural pollen exposure increased J'aw(NO) (p = 0.03), but had no effect on CA(NO) (p = 0.12). In the 18 subjects with pollen allergy who showed a response plateau to AMP in at least one period, the response plateau to AMP increased from a mean of 13.4% (95% CI: 8.2-18.5) out of season to 22.5% (95% CI: 15.5-29.4, p = 0.004) during the pollen season. Similar results were obtained with methacholine. Compared with healthy controls, subjects with pollen allergy had a higher response plateau and higher J'aw(NO) values.

CONCLUSIONS

These findings suggest that inflammatory changes induced by natural allergen exposure in sensitized subjects are predominantly located in the airways and associated with modifications in the shape of the concentration-response curve to direct and indirect agonists.

Early interventions with inhaled corticosteroids in asthma: benefits and risks

PURPOSE OF REVIEW

the present review examines the effects of early intervention with inhaled corticosteroids (ICSs) on clinical efficacy and natural history of asthma based on two recent clinical trials: the Inhaled Steroid Treatment as Regular Therapy in Early Asthma (START) and Prevention of Early Asthma in Kids (PEAK) trials, and a comparison of the effect of regular vs. intermittent therapy based on the Improving Asthma Control Trial (IMPACT).

RECENT FINDINGS

in most patients, both adults and children, who have a new diagnosis of asthma and whose symptoms are mild but persistent, treatment with ICS should be recommended as soon as the diagnosis is made. This is a cost-effective and well tolerated treatment. However, symptoms may recur and lung function may decline again if treatment is discontinued.

SUMMARY

ICS is the most cost-effective initial treatment for both adults and children with a new diagnosis of asthma. If patients are reluctant to use ICS daily for long periods, it would be reasonable to delay the onset of treatment with ICS. Initial therapy with leukotriene receptor antagonist is not likely to be as effective as initial therapy with ICS. Biomarkers of airway inflammation such as sputum cell counts and exhaled nitric oxide are probably not necessary to treat patients with mild intermittent asthma.

Ventilator-Associated Pneumonia

The area of the alveolar epithelium of the lung is approximately 70 m². This area is constantly in contact with the ambient air and is therefore vulnerable to contamination with airborne microbes and particles of respirable size. Due to the configuration of the respiratory tract, airborne particles having diameters in the range of 0.5-2.0 μ can reach and deposit in the terminal part of the tracheobronchial tree - most bacteria are of this size. In reality, very few bacteria cause infections by spreading via the airborne route (e.g., mycobacteria, viruses, and legionella). Most bacteria cause pneumonia by first colonizing the upper respiratory tract and later descending into the tracheobronchial tree.

Focal stenosis in right upper lobe bronchus in a recurrently wheezing child sequentially studied by multidetector-row spiral computed tomography and scintigraphy

Lower respiratory tract infections associated with wheezing are not uncommon in infants and young children. Among the wheezing-associated disorders, allergic etiologies are more commonly encountered than anatomic anomalies. We present a 3-year-old girl with a sudden attack of asthmatic symptoms including dyspnea, cyanosis and diffuse wheezing Based on a history of choking, and atelectasis in the right upper lobe detected by chest films, flexible tracheobronchoscopy was arranged and incidentally detected a stenotic orifice in the right upper lobe bronchus. Multidetector-row spiral computed tomography and pulmonary scintigraphy subsequently also disclosed the focal stenosis. She suffered from recurrent wheezing, pneumonia and lung atelectasis during 1 year of follow-up. We emphasize the diagnosis, clinical course and management of focal stenosis in the right upper lobe bronchus.

Inhaled corticosteroids as combination therapy with beta-adrenergic agonists in airways disease: present and future

Inhaled corticosteroid (ICS) therapy in combination with long-acting beta-adrenergic agonists represents the most important treatment for chronic airways diseases such as asthma and chronic obstructive pulmonary disease (COPD). ICS therapy forms the basis for treatment of asthma of all severities, improving asthma control, lung function and preventing exacerbations of disease. Use of ICS has also been established in the treatment of COPD, particularly symptomatic patients, who experience useful gains in quality of life, likely from an improvement in symptoms such as breathlessness and in reduction in exacerbations, and an attenuation of the yearly rate of deterioration in lung function. The addition of long-acting beta-agonist (LABA) therapy with ICS increases the efficacy of ICS effects in moderate-to-severe asthma. Thus, a 800 mug daily dose of the ICS budesonide reduced severe exacerbation rates by 49% compared to a low dose of 200 mug daily, and addition of the LABA formoterol to budesonide (800 mug) led to a 63% reduction. In COPD, the effects of ICS are less prominent but there are beneficial effects on the decline in FEV(1) and the rate of exacerbations. A reduction in the rate of decline in FEV(1) of 16 ml/year with a 25% reduction in exacerbation rate has been reported with the salmeterol and fluticasone combination. A non-significant 17.5% reduction in all-cause mortality rate with ICS and LABA is reported. Chronic inflammation is a feature of both asthma and COPD, although there are site and characteristic differences. ICS targets this inflammation although this effect of ICS is less effective in patients with severe asthma and with COPD; however, addition of LABA may potentiate the anti-inflammatory effects of ICS. An important consideration is the presence of corticosteroid insensitivity in these patients. Currently available ICS have variably potent binding activities to specific glucocorticoid receptors, leading to inhibition of gene expression by either binding to DNA and inducing anti-inflammatory genes or by repressing the induction of pro-inflammatory mediators. Local side effects of ICS include oral candidiasis, hoarseness and dysphonia, while systemic side effects, such as easy bruising and reduction in growth velocity or bone mineral densitometry, are usually restricted to doses above maximally recommended doses. Use of LABA alone in patients with asthma increases the risk of asthma-related events including deaths, but this is less observed with the combination of ICS and LABA. Therefore, use of LABA alone is not recommended for asthma therapy. Future progress in ICS development will be characterised by the introduction of ICS with greater efficacy with a limited side-effect profile, and by longer-acting ICS that can be used in combination with once-daily LABAs. Other agents that could improve the efficacy of corticosteroids or reverse corticosteroid insensitivity may be added to ICS. ICS in combination with LABAs will continue to remain the main focus of treatment of airways diseases.

Maximal response plateau to adenosine 5'-monophosphate in asthma. Relationship with the response to methacholine, exhaled nitric oxide, and exhaled breath condensate pH

BACKGROUND

No information is available on the plateau in response to adenosine 5'-monophosphate(AMP). The aims of the present study were (1) to determine whether plateau can be detected with AMP and the relation with the plateau in response to methacholine, and (2) to identify the relation between the plateau and indirect markers of airway inflammation, such as exhaled nitric oxide (ENO) and exhaled breath condensate (EBC) pH.

METHODS

Airway responsiveness to high concentrations of methacholine and AMP, ENO levels, and EBC pH values were obtained in 31 subjects with well-controlled asthma. Concentration-response curves were characterized by their concentration of agonist that produces a decrease in FEV(1) of 20% and, if possible, by the level of plateau.

RESULTS

Although the prevalence of plateau with methacholine (48%) and AMP (58%) was similar, the two challenges did not identify plateau in exactly the same individuals. In 14 subjects who showed plateau with both bronchoconstrictor agents, the mean plateau level for methacholine was 26.0% (95% confidence interval [CI], 21.3 to 30.8), compared with 16.5% (95% CI, 12.2 to 20.8; p < 0.0001) for AMP. Both ENO and EBC pH values were similar in subjects with plateau and in those without plateau.

CONCLUSIONS

In well-controlled asthmatics, the plateau in response to AMP can be identified at a milder degree of obstruction than the plateau in response to methacholine, but the two agonists are not identifying the same airway abnormalities. Furthermore, if ENO and EBC pH are markers of inflammation, the determination of the presence or level of plateau is not a reliable method to identify airway inflammation in asthma.

Use of prescription drugs in athletes

Although athletes are young and generally healthy, they use a variety of non-doping classified medicines to treat injuries, cure illnesses and obtain a competitive edge. Athletes and sports medicine physicians try to optimize the treatment of symptoms related to extreme training during an elite athlete's active career. According to several studies, the use of antiasthmatic medication is more frequent among elite athletes than in the general population. The type of training and the kind of sport influence the prevalence of asthma. Asthma is most common among those competing in endurance events, such as cycling, swimming, cross-country skiing and long-distance running. Recent studies show that athletes use also NSAIDs and oral antibacterials more commonly than age-matched controls, especially athletes competing in speed and power sports. Inappropriately high doses and concomitant use of several different NSAIDs has been observed. All medicines have adverse effects that may have deleterious effects on elite athletes' performance. Thus, any unnecessary medication use should be minimized in elite athletes. Inhaled beta(2)-agonists may cause tachycardia and muscle tremor, which are especially harmful in events requiring accuracy and a steady hand. In experimental animal models of acute injury, especially selective cyclo-oxygenase-2 inhibitors have been shown to be detrimental to tissue-level repair. They have been shown to impair mechanical strength return following acute injury to bone, ligament and tendon. This may have clinical implications for future injury susceptibility. However, it should be noted that the current animal studies have limited translation to the clinical setting. Adverse effects related to the CNS and gastrointestinal adverse reactions are commonly reported in connection with NSAID use also in elite athletes. In addition to the potential for adverse effects, recent studies have shown that NSAID use may negatively regulate muscle growth by inhibiting protein synthesis. Physicians and pharmacists taking care of athletes' medication need to be aware of the medicines that an athlete is taking and how those medicines interact with performance, exercise, environment and other medicines. Sport associations should repeatedly monitor not only the use of banned substances, but also the trends of use of legal medicines in athletes. Not only physicians and pharmacists, but also athletes and coaches should be better educated with respect to potential benefits and risks, and how each agent may affect an athlete's performance. The attitudes and beliefs leading to ample use of legal medicines in athletes is an interesting area of future research.

Deep inspiration-induced changes in lung volume decrease with severity of asthma

We have previously reported that the magnitude of deep inspiration (DI)-induced bronchodilation is only slightly reduced in mild asthmatics, compared to healthy subjects. The aim of this study was to evaluate whether increased severity of asthma is associated with impairment in the ability of DI to induce changes in lung volume. Thirty-six consecutive asthmatics recruited from the Pulmonary and the Allergy Outpatient Clinics of the Institute of Respiratory Diseases of the University of Palermo were divided into 3 groups: Intermittent (I), Mild Persistent (MP) and Moderate-Severe (MS), based on GINA guidelines. Single dose methacholine (Mch) bronchoprovocations were performed in the absence of DI, to induce at least 15% reduction in inspiratory vital capacity (IVC) from baseline. The post-Mch IVC was followed by 4 consecutive DI and by another IVC, to determine the bronchodilatory effect of DI. The bronchodilatory effect of DI was found to significantly decrease with increasing severity of asthma (I: 68+/-5.4%, MP: 45+/-7.2%, MS: 4+/-15.6%; ANOVA: P<0.0001). Bronchodilation by DI, but not FEV(1) or FEV(1)/FVC, was also inversely correlated to symptom scores (r=-0.42, P=0.01) and to weekly salbutamol usage (r=-0.47, P=0.004). These observations provide support to the hypothesis that the attenuation of the bronchodilatory effect of DI contributes to the severity of the clinical manifestations of asthma.

Effect of challenge method on sensitivity, reactivity, and maximal response to methacholine

BACKGROUND

Recent data suggest that the tidal breathing method may produce methacholine provocation concentration that caused a decrease in forced expiratory volume in 1 second of 20% (PC20) values significantly lower than the dosimeter method; however, the effect of the challenge method on the shape of the concentration-response curve has not been investigated.

OBJECTIVE

To determine the effect of the challenge method on sensitivity, reactivity, and maximal response to methacholine.

METHODS

We measured airway responsiveness to methacholine using dosimeter and tidal breathing methods in 30 individuals with suspected asthma. Concentration-response curves were characterized by their PC20 (sensitivity), slope (reactivity), and, if possible, level of plateau.

RESULTS

Dosimeter PC20 values were significantly higher than tidal breathing values (geometric mean, 8.9 and 5.2 mg/mL, respectively); the mean difference in PC20 values obtained using each method was 0.78 doubling concentrations (P = .01). The mean slopes were 22.7%/log mg/mL using the tidal breathing method and 24.9%/log mg/mL using the dosimeter method; the mean difference in the slopes obtained using each method was -2.17%/log mg/mL (P = .18). In 10 individuals who showed a plateau with the 2 methacholine challenge tests, the mean level of plateau was 19.8% using the tidal breathing method and 19.5% using the dosimeter method; the mean difference in the plateau values obtained with each method was 0.3% (P = .87).

CONCLUSIONS

Although the tidal breathing method produces methacholine PC20 values significantly lower than the dosimeter method, both methods provide similar values for slope and level of plateau. These results suggest that the technical factors that affect methacholine sensitivity and the shape of the curve are different.

The treatment of asthma in children: inhaled corticosteroids

The evidence that asthma is characterized by extensive inflammation of the airways has warranted the use of inhaled corticosteroid (ICS) in asthma maintenance therapy. Corticosteroid treatment, especially if high or frequent doses are required, is associated with a range of adverse effects including adrenal suppression and impairment in growth and bone metabolism. New corticosteroids are in development, including mometasone furoate, and some of these are predicted to have reduced adverse effects such as the soft steroid ciclesonide. Soft steroids are designed for delivery near to their site of action, to exert their effect and then to undergo controlled and predictable metabolism to inactive metabolites. This review points out the anti-inflammatory effects of corticosteroid in asthmatic airways and the clinical efficacy and safety of ICS in asthmatic children. The development of a soft steroid should help to achieve the aim of improving the therapeutic profile of ICS in asthma and thus alleviate the ongoing problem of poor patient compliance especially in childhood.

Inhaled dexamethasone differentially attenuates disease relapse and established allergic asthma in mice

Inhaled glucocorticoids are effective in patients with chronic allergic asthma. We examined the effects of inhaled glucocorticoids on relapse (allergen challenge after disease remission) and established/overt allergic asthma (repeated allergen challenge in weekly intervals) in mice to establish a reference standard for novel treatments. BALB/c mice were treated before relapse or during overt disease with 1 h of nebulized PBS or 10 mg% dexamethasone twice daily for 5 days. Dexamethasone eliminated airway hyperresponsiveness before relapse and during overt disease. They more efficiently reduced airway inflammation, mucus production, and OVA-specific IgG1 and IgE during relapse compared to overt disease. However, during overt disease, parenchymal inflammatory infiltrates were more effectively eliminated compared to relapse, suggesting that activated infiltrating leukocytes have increased sensitivity to steroids. These data demonstrate that inhaled corticosteroids attenuate relapse and overt disease differentially and suggest that both airway and parenchymal inflammation need to be evaluated for treatment efficacy.

Preclinical properties of budesonide: translation to the clinical setting

BACKGROUND

Since the introduction of inhaled corticosteroids (ICSs) nearly 30 years ago, the management of asthma has been transformed. It is now understood that asthma is primarily a disease of chronic inflammation, even in its milder forms, and that to delay treatment may lead to deterioration in lung function. International treatment guidelines for asthma recommend early intervention with a potent ICS, with the greatest benefit observed when treatment is started within 2 years of the onset of symptoms. Each of the currently available ICSs has distinct physical and pharmacokinetic properties and is delivered via different devices.

OBJECTIVE

This article brings together the findings and concepts presented in this supplement. It provides an overview of budesonide's predicted clinical efficacy and tolerability in patients with asthma based on its physical properties and pharmacokinetic and pharmacodynamic characteristics.

CONCLUSIONS

Budesonide's physical properties and pharmacokinetic and pharmacodynamic profiles help predict its clinical efficacy and tolerability when used as early intervention in asthma. Study results indicate that lung deposition of budesonide is increased by delivery via dry-powder inhaler, enhancing the drug's efficacy in patients with newly diagnosed mild persistent asthma. The preclinical, clinical, and safety data support budesonide's predicted performance in the clinical setting.

Pharmacology of airway inflammation in asthma and COPD

The current asthma therapies are not cures and symptoms return soon after treatment is stopped even after long term treatment. Although inhaled glucocorticoids are highly effective in controlling airway inflammation in asthma, they are ineffective in the small group of patients with glucocorticoid-dependent and -resistant asthma. With very few exceptions, COPD is caused by tobacco smoking, and smoking cessation is the only truly effective treatment of COPD available. Current pharmacological treatment of COPD is unsatisfactory, as it does not significantly influence the severity of the disease or its natural course. Glucocorticoids are scarcely effective in COPD patients without concomitant asthma. Bronchodilators improves symptoms and quality of life, in COPD patients, but, with the exception of tiotropium, they do not significantly influence the natural course of the disease. Theophylline is the only drug which has been demonstrated to have a significant effect on airway inflammation in patients with COPD. Here we review the pharmacology of currently used antiinflammatory therapies for asthma and COPD and their proposed mechanisms of action. Recent understanding of disease mechanisms in severe steroid-dependent and -resistant asthma and in COPD, has lead to the development of novel compounds, which are in various stages of clinical development. We review the current status of some of these new potential drugs.

Inhaled corticosteroids for asthma: common clinical quandaries

This narrative review provides evidence-based explanations to some of the common clinical concerns regarding inhaled corticosteroids. Inhaled corticosteroids are the treatment of choice for a newly diagnosed asthmatic patient. Better results are obtained when treatment is initiated as soon as the diagnosis is made. Asthma control can be achieved and maintained in most patients with a low or moderate dose of inhaled corticosteroid administered in two daily doses. Longer duration of treatment provides more sustained benefits than treatment that is intermittent and for short periods of time. The clinical benefits can be observed within 24 hours of commencing treatment and may be more pronounced in patients with an eosinophilic bronchitis. Inhaled corticosteroids provide additional benefit when used in conjunction with prednisone in acute severe asthma. Low doses do not have clinically deleterious side effects on the bones, growth, eye, or hypothalamo-pituitary-adrenal-axis. However, they do not normalize lung function and prevent structural changes in the airway wall in all asthmatic patients.

Dose response of inhaled corticosteroids on bronchial hyperresponsiveness: a meta-analysis

BACKGROUND

There is a relatively steep dose-response curve for effects of inhaled corticosteroids on conventional airway markers of asthmatic disease control.

OBJECTIVE

We sought to determine whether a dose-response effect exists for bronchial hyperresponsiveness.

METHODS

A meta-analysis of placebo-controlled trials in asthmatic patients was performed using a computerized systematic review of databases. Doubling dose/dilution protection of inhaled corticosteroid was compared with placebo. Studies which used direct (methacholine and histamine) and indirect (adenosine monophosphate) bronchial challenge stimuli were eligible for inclusion.

RESULTS

Twenty-five studies fulfilled eligibility criteria (963 patients). Values for doubling dose/dilution protection categorized by low/medium dose (< 1,000 microg) and high dose (> or = 1,000 microg) of inhaled corticosteroid amounted to a 1.25 (95% confidence interval 1.08 to 1.42) and 2.16 (95% confidence interval 1.88 to 2.44) shift, respectively.

CONCLUSIONS

High doses of inhaled corticosteroids conferred greater improvements in bronchial hyperresponsiveness than low doses.

Theophylline and PDE4 inhibitors in asthma

Over the past three decades, beta -adrenoceptor agonists and glucocorticosteroids have formed the mainstay of treatment for patients with asthma; during this time, only one new drug class, leukotriene receptor antagonists, have been introduced. Theophylline has also been used in the treatment of patients with asthma, although there is a perception that this drug does not offer the patient any advantages over conventional therapeutic strategies. However, a number of clinical studies have documented the efficacy of this orally active drug. The mechanism by which theophylline exerts its well recognized antiinflammatory activity remains to be established but, if explained, could lead to newer drug development with greater efficacy. The development of phosphodiesterase (PDE)4 inhibitors is one such approach, and recent studies have demonstrated the potential utility of this new drug class for the treatment of patients with asthma.(2)

Maximal airway response in adolescents with long-term asthma remission and persisting airway hypersensitivity: its profile and the effect of inhaled corticosteroids

BACKGROUND

Many children with asthma go into long-term clinical remission at adolescence, but bronchial hyperresponsiveness (BHR) persists in some of these subjects. BHR in asthma is characterized by an increase in sensitivity and in maximal airway response to bronchoconstrictor stimuli.

OBJECTIVE

The aims of this study were to compare the profiles of maximal airway response between adolescents with asthma remission and adolescents with symptomatic asthma to a similar degree of airway hypersensitivity, and to determine whether maximal airway response in adolescents with asthma remission is reduced by prolonged treatment with inhaled corticosteroids.

METHODS

A high-dose methacholine inhalation test was performed in 46 adolescents with long-term asthma remission (remission group) and 44 adolescents with symptomatic asthma (symptomatic group). Subjects exhibiting a maximal response plateau in the remission group were administered inhaled budesonide (400 microg bid, budesonide/remission group, n = 15) or identical placebo (placebo/remission group, n = 15) for 6 months, and the subjects in the symptomatic group were administered the same regimen of budesonide (budesonide/symptomatic group, n = 17). The plateau level was measured after 3 months and 6 months of treatment.

RESULTS

Thirty-four subjects (73.9%) in the remission group featured a maximal response plateau on the dose-response curve to methacholine, whereas 19 subjects (43.2%) in the symptomatic group had a plateau (p = 0.003). In neither the placebo/remission group nor the budesonide/remission group did the plateau level change significantly over the 6-month period, whereas budesonide markedly decreased the level in the budesonide/symptomatic group.

CONCLUSION

The difference in frequency of detection of a plateau between the remission group and the symptomatic group, as well as the difference in its response to treatment with budesonide between the two groups, suggests that inflammatory changes impact the maximal airway response in symptomatic asthmatic adolescents but not in adolescents with asthma remission.

Fluticasone inhibits the progression of allergen-induced structural airway changes

BACKGROUND

Inhaled corticosteroids are widely used as first-line therapy in patients with asthma. The concept of early introduction is more and more accepted.

OBJECTIVE

In our rat model of airway remodelling, we investigated whether treatment with inhaled fluticasone propionate can inhibit further progression of established structural airway changes.

METHODS

Sensitized Brown Norway rats were exposed to aerosolized ovalbumin (1%) from day 14 to 42. From day 28 to 42, animals were treated with inhaled fluticasone or placebo 30 min before each allergen challenge. One control group was exposed to PBS from day 28 to 42, a second control group throughout the whole experiment.

RESULTS

Exposure to ovalbumin during 2 weeks induced structural airway changes, including epithelial cell proliferation, increase in airway wall area and fibronectin deposition. Goblet cell number was increased, although not significantly compared with PBS. Continuing allergen exposure for 2 weeks further enhanced each of these features. In addition, the amount of collagen in the airway wall was enhanced by 4 weeks allergen exposure compared with PBS-exposed animals. These additional increases were inhibited by treatment with fluticasone during the last 2 weeks.

CONCLUSION

The progression of established allergen-induced structural airway changes in sensitized rats can be inhibited by treatment with fluticasone.

Relationship of airway responsiveness with airway morphometry in normal and immunized rabbits

Airway responses to chemical stimuli occur over a wide range of concentrations, with overlap between severe, moderate and mild asthmatic groups and with normal healthy individuals. Mathematical modelling has suggested that relative thickness of the airway wall may account for this range of responsiveness. We have investigated whether in vivo airway responsiveness varies as a function of airway wall thickness in terms of airway smooth muscle area in normal and immunized New Zealand White (NZW) rabbits. Airway responsiveness to inhaled methacholine (MCh) was determined in vivo under neuroleptanalgesia. Subsequently, ex vivo responsiveness to MCh (pD(2)=-log EC(50)) of isolated bronchi from the same animal was established. Smooth muscle area per mm basement membrane (SM/mmBM) was also measured morphometrically in the tested bronchi and the findings related to in vivo and ex vivo responsiveness. We found no relationship between airway responsiveness in vivo and pD(2)values in either immunized or control rabbits. In both control and immunized rabbits, no correlation was found between SM/mmBM and in vivo airway responsiveness. Only in immunized animals with a PCA titre >0, was there a significant correlation (=-0.5986, P<0.05) between SM/mmBM and pD(2). We conclude that airway smooth muscle area per se is not the sole contributor of airway responsiveness in vivo in normal rabbits.

Relationship between airway sensitivity to adenosine 5' monophosphate and the shape of the concentration-response curve to methacholine in subjects with allergic rhinitis

The objective of this study was to determine differences in airway sensitivity to adenosine 5'-monophosphate (AMP) between allergic rhinitis subjects with plateau and those without evidence of plateau on the concentration response curves to methacholine. A total of 51 adults (38 subjects with allergic rhinitis and 13 healthy controls) were challenged with increasing concentrations of methacholine and AMP. The methacholine challenge was terminated when there was a 40% or more decrease in forced expiratory volume in 1 sec (FEV1), whereas the AMP challenge was stopped when FEV1 had fallen by more than 20%. A plateau for methacholine was detected in all 13 healthy controls and in 27 patients with allergic rhinitis (AR-plateau group), whereas 11 subjects with allergic rhinitis did not exhibit a plateau (AR-non-plateau group). The median (range) PC20 AMP (provocative concentration required to produce a 20% fall in FEV1) value for the AR-non-plateau group was 44.0 mg ml(-1) (3.3-400.0), compared with 400.0 mgml(-1) (12.1-400.0) in the AR-plateau group (P=0.03) and 400.0 mgml(-1) in the healthy control group (P=0.007). The proportion of subjects who showed bronchoconstriction in response to AMP was higher in the AR-non-plateau group (73%) than in the AR-plateau group (30%) (P=0.03). However, three subjects with allergic rhinitis who had normal sensitivity to methacholine and plateau showed bronchoconstriction in response to AMP. We conclude that, in subjects with allergic rhinitis, the absence of plateau on the concentration response curves to methacholine is associated with a higher prevalence and degree of bronchoconstriction in response to AMP. However, the two bronchoconstrictor stimuli were not identifying the same abnormalities of the airways.

Changes in indices of airway hyperresponsiveness during one year of treatment with inhaled corticosteroids in patients with asthma

We analyzed the changes in indices of airway hyperresponsiveness, including hypersensitivity and hyperreactivity, during one year of treatment with inhaled corticosteroids. We then investigated on which of them the inhaled corticosteroids had a primary effect. Fifty outpatients with asthma were recruited and treated with inhaled beclomethasone dipropionate. They underwent bronchoprovocation tests on the initial visit and at 3, 6, and 12 months. The dose of methacholine required to produce a 20% fall in the forced expiratory volume in 1 second (PD20-FEV1) was measured to evaluate airway hypersensitivity. A relatively novel index, the percent change in the forced vital capacity (deltaFVC%) at the PD20-FEV1, was assessed as a marker of airway hyperreactivity. PD20-FEV1 and deltaFVC% were assumed to indicate the horizontal shift of the dose-response curve and the vertical change in the maximal response plateau, respectively. Log(PD20-FEV1) and deltaFVC% continued to improve throughout the year (p < 0.001 and p = 0.002, respectively). Log(PD20-FEV1) improved significantly at the 3-month evaluation (p < 0.001), and deltaFVC% improved at the 6-month evaluation (p = 0.012). Log(PD20-FEV1) had no or weak relationships with deltaFVC% at all evaluation points. In conclusion, inhaled corticosteroids continued not only to reverse the leftward shift of the curve, but also to restore the plateau. Furthermore, their effect was reflected primarily by the former rather than the latter: They should be followed separately to examine how much airway inflammation is reduced.

Budesonide for chronic asthma in children and adults

BACKGROUND

Inhaled budesonide is a widely used inhaled corticosteroid for asthma.

OBJECTIVES

The objectives of this review was to compare the efficacy of budesonide with placebo in the treatment of chronic asthma.

SEARCH STRATEGY

The Cochrane Airways Group Trial Register and reference lists of articles was searched. We contacted trialists for additional studies and searched abstracts of major respiratory society meetings (1997-1999).

SELECTION CRITERIA

Randomised trials in children and adults comparing budesonide to placebo in the treatment of chronic asthma.

DATA COLLECTION AND ANALYSIS

Two reviewers independently assessed articles for inclusion and methodological quality. One reviewer extracted data.

MAIN RESULTS

43 studies met the inclusion criteria (2801 subjects). In non-oral steroid treated asthmatics, budesonide led to significant improvements in a number of measures of airway function. These included FEV1, Weighted Mean Difference (WMD) 3.7% predicted (95% CI 0.1, 7.2%); improvement in morning peak flow (PEF) from baseline WMD 29 L/min (95% CI 22, 36 L/min); improvement in evening PEF from baseline WMD 21 L/min (95% CI 13, 29 L/min). Varying methods of reporting symptoms limited the pooling of studies but all high methodological quality studies demonstrated significant improvements compared to placebo. Health status was not reported. Risk of trial withdrawal due to asthma exacerbation was lower with budesonide compared to placebo, relative risk 0.17 (95% CI 0.09, 0.33). Doses of 500-800 mcg/d appeared to have slightly larger effect sizes than lower doses, but no advantage for high doses were apparent. A single high quality RCT reported significant reductions in daily prednisolone requirement and the number of patients able to discontinue prednisolone completely in budesonide treated subjects compared to placebo. No difference in risk of oropharyngeal soreness/hoarseness or oral Candidiasis was apparent for budesonide compared to placebo. Long-term risk of adrenal insufficiency was not reported.

REVIEWER'S CONCLUSIONS

This review strongly supports use of budesonide in chronic asthma. Consensus guidelines for chronic asthma suggest titrating inhaled steroid dose to individual requirements. Evidence from this review of trials does not present a case for routine dose titration above 800 mcg/d.

Therapeutic ratio of inhaled corticosteroids in adult asthma. A dose-range comparison between fluticasone propionate and budesonide, measuring their effect on bronchial hyperresponsiveness and adrenal cortex function

Inhaled corticosteroids have become the mainstay treatment of bronchial asthma. However, simultaneous evaluations of efficacy and side effects are few. This study aimed to compare the relative effect of fluticasone propionate (FP) and budesonide (BUD) on bronchial responsiveness and endogenous cortisol secretion in adults with asthma. The study was double-blind and included 66 adults with asthma, who were randomized to FP (n = 33) or BUD (n = 33). Prestudy, all participants were clinically stable, using inhaled corticosteroids and hyperresponsive to methacholine. Eligible patients were randomized to three consecutive 2-wk periods with either FP 250 microg twice daily, FP 500 microg twice daily, and FP 1,000 microg twice daily, or BUD 400 microg twice daily, BUD 800 microg twice daily, and BUD 1,600 microg twice daily, delivered by Diskhaler and Turbuhaler, respectively. Before randomization and at the end of each treatment, bronchial methacholine PD(20), 24-h urinary cortisol excretion (24-h UC), plasma cortisol, serum osteocalcin, and blood eosinophils were determined. The relative PD(20) potency between FP and BUD was 2.51 (95% CI, 1.05-5.99; p < 0. 05), while the relative 24-h UC potency was 0.60 (95% CI, 0.44-0.83; p < 0.01). The differential therapeutic ratio (FP/BUD) based on PD(20) potency and 24-h UC was 4.18 (95% CI, 1.16-15.03; p < 0.05). The difference in systemic potency was also seen for plasma cortisol, serum osteocalcin, and blood eosinophils. Therapeutic ratio over a wide dose range, determined by impact on bronchial responsiveness and endogenous corticosteroid production, seems to favor FP.

The placebo effect in asthma drug therapy trials: a meta-analysis

A meta-analysis of randomized controlled asthma drug therapy trials published in the English literature from January 1991 to June 1995 was performed to estimate the magnitude and direction of the placebo effect in stable ambulatory asthmatic patients. Among placebo groups, the mean absolute increase in forced expiratory volume in 1 sec (FEV1), weighted for sample size and variance, was 0.11 L/min, and the mean percent increase in FEV1 was 4.81%. The corresponding placebo group changes in peak expiratory flow (PEF) were in an opposite direction to those of FEV1; there was a mean absolute decrease of 2.24 L/min, and a mean percent decrease of 4.21%. Changes for active treatment groups were greater in magnitude. However, there were no statistically significant differences in mean changes comparing the placebo groups to the treatment groups, for any of the outcome measures. Mean increases in PEF and FEV1 exceeded 10% in 5 of 33 placebo groups, as compared to 13 of 33 active treatment groups. In conclusion, in well-designed long-term drug therapy studies in stable asthmatics the pooled placebo effect is small but measurable, with FEV1 and PEF showing different directions of response. Moreover, a modest number of patients receiving placebo have changes in pulmonary function that might be interpreted as clinically significant.

Tissue remodeling as a feature of persistent asthma

A chronic inflammatory process is almost invariably associated with tissue damage and healing. Healing results in repair and replacement of dead or damaged cells by viable cells. Repair usually involves 2 distinct processes: regeneration, which is the replacement of injured tissue by parenchymal cells of the same type, and replacement by connective tissue and its eventual maturation into scar tissue. In many instances both processes contribute to the healing response. Chronic inflammatory disease can therefore lead to a wide variety of consequences, from complete or partial restitution of organ structure and function to fibrosis. Asthma is characterized by a chronic inflammatory process of the airways. The ensuing healing process results in structural alterations referred to as a remodeling of the airways. The mechanisms underlying these structural alterations are still largely unknown. They are likely to be heterogeneous, leading-through the highly dynamic process of cell de-differentiation, migration, differentiation, and maturation-to changes in connective tissue deposition and to the altered restitution of airways structure, resulting in mucus gland hyperplasia, neovascularization, fibrosis, and an increase in smooth muscle mass.

Equivalent asthma control after dose reduction with HFA-134a beclomethasone solution aerosol. Comparative Inhaled Steroid Investigation Group (CISIG)

AIM

The replacement of chlorofluorocarbon (CFC) by hydrofluoroalkane has the potential to improve airway deposition of BDP. We investigated whether HFA-BDP extra-fine solution aerosol 400 microg day(-1) is as effective as CFC-BDP 1000 micro day(-1) in patients with stable, moderate asthma, having persistent bronchial hyperresponsiveness.

PATIENTS AND METHODS

One hundred and fifty patients with moderate asthma from 20 centres, on inhaled steroids for < or = 3 months, entered a 4-week run-in period with 1000 microg day(-1) CFC-BDP. Patients were then allocated to a 10-week study phase, receiving CFC-BDP 1000 microg day(-1) or HFA-BDP 400 microg day(-1). Symptom score and PEF were measured daily and recorded as biweekly means. Spirometry, PC20FEV1, blood eosinophils and serum ECP were determined on days 15, 29, 43 and 71, and compared to the last visit of the run-in period. All group members were trained in a quality control centre.

RESULTS

Treating the population of the HFA-BDP group (n = 72) and the CFC-BDP group (n = 78) did not show significant differences in terms of symptoms, lung function, airway hyperresponsiveness and serum markers of inflammation at the end of the run-in period and the end of the study phase.

CONCLUSION

Using HFA instead of a CFC metered dose inhaler, containing less than half the daily dose of BDP, allows control of symptoms and lung function parameters, without changes in bronchial hyperresponsiveness.

Bronchial responsiveness among inbred mouse strains. Role of airway smooth-muscle shortening velocity

To investigate the relationship between bronchial responsiveness and airway smooth-muscle (ASM) contractile properties, we studied inbred mice with known interstrain differences in airway responsiveness. Using oscillatory mechanics, we confirmed that A/J mice were hyperresponsive to methacholine (MCh) as compared with mice of the C3H/HeJ and C57BL/6J strains. Analysis of respiratory system resistance and elastance at different flow oscillation frequencies indicated that interstrain differences in responsiveness are present in both central and peripheral airways of these mice. We used video microscopy to measure the rate of contraction of explanted airways, and found that the airways of A/J mice contracted more rapidly than those of C3H/HeJ or C57BL/6J mice. In studies of a fourth strain (Balb/C) of mice, we found both bronchial hyperresponsiveness and increased ASM shortening velocity. The rank order of responsiveness among strains was the same as that for shortening velocity (A/J > Balb/C > C3H/HeJ > C57BL/6J). Furthermore, in each strain of mice, shortening velocity correlated with the achieved degree of airway narrowing and with a greater likelihood of airway closure in individual airways. In contrast, generation of isometric tension in trachealis, morphometric measurements of tracheal ASM, tracheal myosin content, and dose-response curves for MCh of explanted intraparenchymal bronchi failed to correspond to the in vivo phenotype of airway reactivity. These results indicate that bronchial responsiveness is related to ASM shortening velocity, and underscore the importance of smooth-muscle dynamics in understanding the mechanisms of bronchial responsiveness.

Allergic inflammation in upper and lower airways

OBJECTIVE

The primary reason for this review is to discuss the relationship between upper and lower airways at various levels with the emphasis on common pathophysiologic mechanisms, and how treatment of the upper airways will benefit the lower airways.

DATA SOURCES

The main source of information is derived from original articles and books, with an extensive bibliography included.

STUDY SELECTION

Studies were derived almost exclusively from articles and reviews in peer-reviewed journals.

RESULTS

The prevalence of rhinitis and asthma are both increasing. Common to both the upper and lower airways are the triggers, many of the inflammatory cells and mediators, and the treatment modalities. By contrast, there are organ-specific differences in the reaction to various stimuli in the nose or lung, with each organ manifesting its own vocabulary of response.

CONCLUSIONS

There are meaningful relationships between upper and lower airways at various levels of our understanding. Differential responses to medications help us better understand pathogenic mechanisms in rhinitis and asthma. Further, treatment of the upper airways provides additional benefit to the lower airways.

Effect of inhaled corticosteroids on bronchial responsiveness in patients with "corticosteroid naive" mild asthma: a meta-analysis

BACKGROUND

Inhaled corticosteroids are the most efficacious anti-inflammatory drugs in asthma. International guidelines also advocate the early introduction of inhaled corticosteroids in corticosteroid naive patients. A study was undertaken to assess the effects of inhaled corticosteroids on bronchial hyperresponsiveness in patients with corticosteroid naive asthma by conventional meta-analysis.

METHODS

A Medline search of papers published between January 1966 and June 1998 was performed and 11 papers were selected in which the patients had no history of treatment with inhaled or oral corticosteroids. Bronchial responsiveness to bronchoconstricting agents was considered as the main outcome parameter. Doubling doses (DD) of histamine or methacholine were calculated.

RESULTS

The total effect size of inhaled corticosteroids (average daily dose 1000 microg) versus placebo in the 11 studies was +1.16 DD (95% confidence interval (CI) +0.76 to +1.57). When only the eight short term studies (2-8 weeks) were analysed the effect size of the bronchoconstricting agent was +0.91 DD (95% CI +0.65 to +1.16). No relationship was found between the dose of inhaled corticosteroid used and the effect on bronchial responsiveness.

CONCLUSION

This meta-analysis in patients with corticosteroid naive asthma indicates that, on average, high doses of inhaled corticosteroids decrease bronchial hyperresponsiveness in 2-8 weeks. It remains unclear whether there is a dose-response relationship between inhaled corticosteroids and effect on bronchial hyperresponsiveness.

The role of theophylline in asthma management

Views on the appropriate use of theophylline in asthma management have varied substantially over the past decades. The recent emphasis on potential anti-inflammatory effects of theophylline has only added to the debate. In current guidelines, theophylline has been positioned mainly as a form of "add-on" therapy in moderate to severe persistent asthma. The purpose of this review is to analyze whether recent developments have been made that allow for a further positioning of theophylline in the treatment of asthma.

Effects of inhaled corticosteroids on the consequences of asthma

Asthma is a chronic inflammatory disease of the airways involving a characteristic pattern of airway infiltration with lymphocytes, eosinophils, and mast cells, subepithelial deposition of collagen, and hypertrophy and hyperplasia of smooth muscle and of goblet cells and submucosal glands. The consequences of this chronic process include episodic or persistent symptoms, bronchial hyperreactivity, attacks of bronchoconstriction that may require emergency care or hospitalization and can lead to death, impairment in quality of life, and the development of irreversible airflow obstruction. Careful pathologic studies have shown that inhaled corticosteroid therapy can reverse or suppress airway inflammation, and prospective controlled clinical trials have proven that it can also improve symptoms, reduce bronchial hyperreactivity, and reduce the frequency and severity of attacks. It is also highly likely, although it is not yet proven, that inhaled corticosteroid therapy reduces the risk of asthma fatality and prevents or retards airway wall remodeling. These beneficial effects are easily shown in patients with moderate or severe asthma. Although inhaled corticosteroid therapy also benefits patients with mild asthma, it is less certain that the costs and risks of continuous therapy are justified. For these patients, the most important issues that remain to be resolved are the nature of the risk of development of permanent airflow obstruction and the effects of early, sustained treatment on the chances of sustained remission of asthma after all therapy has been stopped.

An overview of nine clinical trials of salmeterol in an asthmatic population

In an attempt to establish the protection afforded by regular salmeterol use against induced bronchoconstriction in asthmatic patients, a meta-analysis was conducted on nine double-blind clinical trials that fulfilled the inclusion criteria. In each trial, subjects were randomly assigned to receive either salmeterol 50 micrograms twice daily or a comparator (placebo or salbutamol). Two hundred and twenty-five asthmatic subjects had at least one PC20 or PD20 (histamine or methacholine concentration or dose producing 20% fall in forced expiratory volume in 1 s) measurement recorded within 1 h to 16 weeks after the first dose, and up to 31 days after the last dose, of medication. One hour after the first dose of salmeterol, there was a 3.5-fold increase in doubling dose compared to baseline. Within 12 h of the first dose, the level of protection was 1.5 doubling doses, and protection was maintained at 0.5-1.5 doubling doses over 16 weeks' treatment. This level of protection was maintained for up to 60 h after the last dose. At no time during the washout period did the level of protection fall below zero. Salmeterol afforded significantly greater protection at all time points during the treatment period than comparator agents, but there was no significant difference during the washout period. In conclusion, salmeterol affords protection against bronchoconstrictor stimuli, and any reduction in this bronchoprotective effect occurred during the first few days of treatment. During long-term salmeterol treatment, there was maintained significant protection that showed no evidence of attenuation after 16 weeks' treatment. Furthermore, there was no evidence of rebound deterioration in bronchial responsiveness after cessation of salmeterol treatment.

Current issues for establishing inhaled corticosteroids as the antiinflammatory agents of choice in asthma

Airway inflammation appears to be present even in the mildest of asthma, and inhaled corticosteroids now form the mainstay of asthma therapy. Inhaled corticosteroids largely avoid the adverse effects associated with oral steroids and are now recommended in newly detected disease. Inhaled corticosteroids reduce airway inflammation, airway hyperresponsiveness, and the symptoms of asthma and improve lung function, irrespective of the patient's age or asthma severity. Several different inhaled corticosteroids are available as therapeutic options for the treatment of asthma, and these include fluticasone propionate, beclomethasone dipropionate, and budesonide. The efficacy and safety of inhaled corticosteroids are compared in this article, and inhaled corticosteroid therapy is also compared with other therapies. Recently, there has been a consensus that the optimal use of inhaled corticosteroids for asthma management is using a "start high--go low" approach, and the reasons for this are discussed.