A new approach to the treatment of asthma

Neutrophilic respiratory tract inflammation and peripheral blood neutrophilia after grain sorghum dust extract challenge

STUDY OBJECTIVE

To determine if inhalation of grain sorghum dust in the laboratory would cause neutrophilic upper and lower respiratory tract inflammation in human volunteers, as well as systemic signs of illness.

DESIGN

Prospective.

SETTING

University of Nebraska Medical Center.

PARTICIPANTS

Thirty normal volunteers.

INTERVENTIONS

Inhalation challenge with 20 mL of a nebulized solution of filter-sterilized grain sorghum dust extract (GSDE). One group received prednisone, 20 mg for 2 days, prior to the challenge.

MEASUREMENTS AND RESULTS

Bronchoscopy with bronchoalveolar lavage (BAL) was performed 24 h after challenge, with samples collected as bronchial and alveolar fractions. Findings included visible signs of airways inflammation, quantified as the bronchitis index. The percentage of bronchial neutrophils was significantly increased in those challenged with GSDE vs the control solution, Hanks' balanced salt solution (40.3 +/- 4.5% vs 14.3 +/- 5.1%, p < or = .01). Similar findings were seen in the alveolar fraction. Pretreatment with corticosteroids did not prevent the rise in neutrophils recovered by BAL. Peripheral blood neutrophils were also increased in volunteers challenged with the grain dust extract. To explain the increase in peripheral blood neutrophil counts, the capacity of the peripheral blood neutrophils to migrate in chemotaxis experiments was examined. The results demonstrate an increase in peripheral blood neutrophils and an increase in chemotactic responsiveness.

CONCLUSIONS

Inhalation challenge with a grain dust extract causes respiratory tract inflammation and a peripheral blood neutrophilia. One reason for this may be an increase in activated peripheral blood neutrophils.

Comparison of the effects of salmeterol and salbutamol on clinical activity and eosinophil cationic protein serum levels during the pollen season in atopic asthmatics

BACKGROUND

In atopic asthma there is strong evidence of eosinophils playing an active role in pathogenesis. Some investigations demonstrated that eosinophil cationic protein (ECP) serum levels increased in atopic patients with asthma during pollen season.

OBJECTIVE

The aim of the study was to evaluate the effects of short-term (1 week) beta 2-agonist treatment on lung function and eosinophil activity in asthmatic patients.

METHODS

We used an open, randomized, cross-over design to compare the effects of salbutamol (200 micrograms q.i.d.) and salmeterol (50 micrograms b.i.d.) on peak expiratory flow rate (PEFR), blood eosinophil count and serum levels of ECP as a measure of eosinophil activity in 20 mild atopic asthmatics.

RESULTS

Morning and evening PEFR values were both significantly higher during salmeterol treatment than during the salbutamol period. Conversely, both morning and evening daily asthma symptom scores were significantly lower during salmeterol treatment compared with those recorded during the salbutamol period. The mean basal eosinophil blood count on salmeterol treatment (601 +/- 189 mm3) was not higher than the mean count on salbutamol treatment (612 +/- 204 mm3). After both treatments the mean eosinophil blood counts were unchanged (619 +/- 189 mm3 and 576 +/- 212 mm3, respectively). No significant differences in blood eosinophil counts were observed between or within treatments at any time. No significant difference was observed in baseline mean ECP serum concentration (43.8 +/- 26.3 micrograms/L on salmeterol treatment and 41.7 +/- 29.8 micrograms/L on salbutamol treatment, respectively). After salmeterol treatment the mean ECP serum concentration had fallen significantly to 20.9 +/- 18.6 micrograms/L (P < 0.01), whereas after salbutamol treatment it was unchanged (42.0 +/- 25.1 micrograms/L). Salmeterol treatment produced a decrease in ECP serum levels without any changes in blood eosinophil count.

CONCLUSION

This study demonstrates that salmeterol affords a significant improvement in asthma control during the pollen season, measured by both subjective and objective parameters, compared with salbutamol. This greater efficacy may be related to inhibition of eosinophil degranulation during the pollen season.

Cost comparison of beta 2-agonist bronchodilators used in the treatment of asthma

Because of increases in the morbidity and mortality associated with asthma, coupled with shrinking health care resources, the costs associated with therapy with beta 2-agonists in metered-dose inhalers (MDIs), the most frequently used class of therapeutic agents, were examined. Recent recommendations suggested a change in drug therapy for asthma, away from theophylline and toward patient-administered MDIs containing beta 2-agonists or corticosteroids. These recommendations are expected ultimately to reduce overall costs by decreasing morbidity due to asthma and by reducing hospital services. Furthermore, differences exist among the various beta 2-agonists. For example, for patients treated with albuterol inhalers, total asthma drug costs, the costs of additional asthma drugs, and hospital costs were lower than those for patients treated with metaproterenol inhalers, despite the higher acquisition cost of albuterol. Using the maximum recommended number of daily inhalations and standardized pricing data, the daily costs of nine individual beta 2-agonists in MDIs were calculated. These varied from $0.61 for albuterol to $1.28 for pirbuterol, but would be lower for patients who required fewer daily inhalations on an as-needed basis. In addition, agents that can be dosed as needed (i.e., albuterol) are likely to be more cost-effective choices for formularies than more expensive new bronchodilators such as salmeterol, which must be given twice/day on a regular basis.

Glucocorticoids and growth in asthmatic children

The effects of asthma and oral and inhaled glucocorticoid therapy on growth in children are reviewed. Previous reports have shown that asthma itself may delay the onset of puberty, an effect which may masquerade as growth suppression. Oral glucocorticoids appear to impair growth; however, lower doses and alternate-day therapy may have less risk of this effect. While a controversial topic, inhaled glucocorticoids in lower doses appear to be associated with a small risk of adverse effects on growth. Minimal data are available for higher doses. Knemometry, a relatively new technique used for measuring small changes in growth, has detected short-term effects with both oral and inhaled glucocorticoids therapy. However, a number of limitations are associated with short-term growth studies. Clinicians should be aware of the potential for growth impairment with glucocorticoid therapy so adequate monitoring can be undertaken and appropriate intervention introduced when deemed necessary.

Changes in calcium and bone metabolism during treatment with low dose prednisone in young, healthy, male volunteers

The effect of low dose prednisone on calcium and bone metabolism was evaluated in 8 healthy, young, male volunteers. Sodium and calcium intake were kept stable during the whole study period of 7 weeks. Week 0 was the baseline period; during week 1, 3 and 5 prednisone (10 mg/day) was given, during week 3 together with 500 mg elementary calcium and during week 5 with 4000 IU vitamin D on alternate days. During week 2, 4 and 6 no medication was given. No changes occurred in fasting urinary excretion of calcium or hydroxyproline, nor in serum levels of alkaline phosphatase, 25-Vitamin D, PTH, creatinine and inorganic phosphorus. A rapid decrease of serum osteocalcin during prednisone intake was found (p<0.01). This dip also occurred during prednisone and vitamin D treatment, but did not occur when calcium was added to prednisone, although the baseline value was lower at the start of combined treatment with prednisone and calcium. Serum calcium decreased during prednisone (p<0.05), but when prednisone was given together with calcium, an increase of serum calcium was found (p< 0.05). It is concluded that 10 mg prednisone/day decreases bone formation, as shown by its effect on osteocalcin, while no influence is seen on bone resorption. Thus, prednisone, even when used in low doses, influences bone metabolism by uncoupling bone formation (decreased) and bone resorption (unchanged). These data suggest that the Cs-associated decrease in serum osteocalcin and in serum calcium does not occur during calcium suppletion.

Studies on the inhibition of rejection of Trichostrongylus colubriformis larvae from immune sheep

A total of 8 drugs were examined for their ability to suppress the rejection of Trichostrongylus colubriformis infective larvae (L3) from immune sheep. Specific antagonists of leukotrienes (piroxicam), prostaglandin (indomethacin) and the immunosuppressant cyclosporin A were given orally, while injectable preparations of dexamethasone, chlorpheniramine, BN 52051, WEB 2086 (anti-platelet-activating factor) and theophylline were administered as directed. The drugs were given for 5 days prior to and 4 days after challenge with 20,000 L3, when worm counts were done. Corticosteroids inhibited rejection by around 70% in two experiments, and none of the remaining compounds were effective. In the third study, six of the drugs were given to susceptible sheep and did not affect the establishment of a primary infection with T. colubriformis.

Intravenous magnesium sulfate as an adjunct in the treatment of acute asthma

STUDY OBJECTIVE

This study was conducted to determine whether intravenous magnesium sulfate (MgSO4), when used as part of a standardized treatment protocol, can improve pulmonary function and decrease admission rate in patients presenting to the emergency department with exacerbations of asthma.

DESIGN

In this randomized double-blind placebo-controlled study, patients with acute asthma were treated with inhaled beta-agonists at regular intervals and intravenous (IV) steroids. At 30 min after entry, patients received either 2 g IV MgSO4 or IV placebo. Patients were monitored for up to 4 h with regular measurements of pulmonary function. Patients who were discharged from the emergency department were contacted at 1 day and 7 days for follow-up.

SETTING

Emergency departments of a university-affiliated, voluntary hospital and municipal hospital.

PARTICIPANTS

Asthmatics aged 18 to 65 years during acute exacerbation with FEV1 less than 75% predicted both before and after a single albuterol treatment.

INTERVENTIONS

Patients were given 2 g of MgSO4 or placebo as an adjunct to standardized emergency department procedure for acute asthma.

MEASUREMENTS AND RESULTS

One hundred thirty-five patients were studied. Hospital admission rates were 35.3% for placebo-treated group and 25.4% for the magnesium-treated group (p = 0.21). FEV1 measured at 120 min was 56% predicted for the placebo-treated group and 55% predicted for the magnesium-treated group. (p = 0.92) For subgroup analysis, patients were divided into "severe" (baseline FEV1 < 25% predicted on presentation) or "moderate" (baseline FEV1, 25 to 75% predicted on presentation). For the severe group, admission rates were 78.6% (11/14) for the placebo-treated group and 33.3% (7/21) for the magnesium-treated group (p = 0.009). For the moderate patients, admission rates were 22.4% (11/49) for the placebo-treated group and 22.2% (10/25) for the magnesium-treated group (p = 0.98). There was no significant improvement in FEV1 in the moderate group for magnesium-treated patients. However, in the severe group, there was a significant improvement in FEV1 at 120 min and 240 min (p = 0.014 and 0.026, respectively).

CONCLUSION

Intravenous MgSO4 decreased admission rate and improved FEV1 in patients with acute severe asthma but did not cause significant improvement in patients with moderate asthma.

Beta-adrenoceptor regulation and functional responses in the guinea-pig following chronic administration of the long-acting beta 2-adrenoceptor agonist formoterol

Formoterol is a long acting beta 2-adrenoceptor agonist designed for the alleviation of the symptoms of asthma. This study examined the effects of 14 day administration of formoterol (200 micrograms/kg/day i.p.) on beta 1- and beta 2-adrenoceptors in guinea-pig cardiac and lung tissue. Quantitative autoradiography was used to measure changes in receptor density and organ bath studies determined alterations in functional response. Formoterol treatment produced marked reductions of between 43% and 77% in beta 2-adrenoceptor density in all regions of the heart (atrioventricular node, bundle of His, right and left bundle branches, interventricular and interatrial septa, right and left atria, ventricles and apex) and lung (bronchial and vascular smooth muscle and parenchyma) (P < 0.01, n = 6). beta 1-Adrenoceptor density remained unchanged in all cardiac and lung regions. In functional studies (-)-isoprenaline was 4 fold less potent at causing relaxation of carbachol (1 microM) precontracted tracheal smooth muscle (pD2: control 8.49 +/- 0.03, formoterol 7.91 +/- 0.10, P < 0.001, n = 4), but formoterol treatment did not change the ability of (-)-isoprenaline to elicit a maximum response. The pKB values for ICI 118,551, 7.33 +/- 0.08 in the control and 7.20 +/- 0.01 in formoterol treated animals, were between those expected for beta 1- and beta 2-adrenoceptors suggesting involvement of both subtypes in the response. In spontaneously beating right atria and electrically paced left atria, tissues in which responses are largely mediated by beta 1-adrenoceptors, there was no significant change in responses to (-)-isoprenaline (right atria pD2: control 8.45 +/- 0.02; formoterol 8.42 +/- 0.11; P = 0.77, n = 4) (left atria pD2: control 8.25 +/- 0.03; formoterol 8.47 +/- 0.08; P = 0.09, n = 4). In the presence of CGP 20712A (100 nM) the pKB values did not change with formoterol treatment (left atria: control 9.59 +/- 0.12, formoterol 9.66 +/- 0.12; P = 0.70, n = 4) (right atria: control 8.93 +/- 0.11, formoterol 9.11 +/- 0.07; P = 0.25, n = 4). The doses and route of administration of formoterol used in this study differs from those used clinically. However, this study demonstrates that chronic formoterol administration produces selective down-regulation of beta 2-adrenoceptors in the lung and heart. The changes in the lung are accompanied by a shift to the right in the concentration-response curve to beta-agonist stimulation with no change in the maximum response.

Is bronchial asthma a pancreatic disease?

Bronchial asthma and diabetes mellitus seldom occur in the same patient. The exact mechanism of this mutual exclusion is still unknown and its elucidation can make clear the physiopathology of both diseases. Clinical and experimental evidences suggest that insulin is a proinflammatory hormone and glucagon an antiinflammatory and a bronchodilator one. We hypothesize that the relationship between plasma insulin and glucagon may play an important role in bronchial asthma.

Effects of NIP-502 on antigen-induced bronchial responses and allergic reactions in animal models

We examined the effect of a newly synthesized pyridazinone derivative, NIP-502 [4-chloro-5-(3-ethoxy)-4-phenoxybenzamine)-3(2H)-pyridazinone], on antigen-induced bronchial responses and allergic reactions in several animal models. NIP-502 (10 mg/kg, p.o.) inhibited the antigen-induced immediate asthmatic response in passively sensitized guinea pigs. The inhibitory effect was also observed in metyrapone (an inhibitor of 11 beta-hydroxylase)-pretreated guinea pigs. NIP-502 improved ovalbumin (OA)-induced airway hyperresponsiveness to acetylcholine and inhibited the OA-induced increase in the number of inflammatory leukocytes in the bronchoalveolar lavage fluid. These inhibitory effects on OA-induced responses were similar to those of prednisolone. NIP-502 also showed an inhibitory effect on the passive cutaneous anaphylactic reaction in rats but did not inhibit the reversed cutaneous anaphylactic reaction, reversed Arthus reaction or delayed type hypersensitivity reaction. On the other hand, prednisolone showed broad inhibitory effects except for the reversed cutaneous anaphylactic reaction. In the in vitro study, NIP-502 (30 microM) significantly inhibited Formyl-Met-Leu-Phe-induced superoxide anion production by the guinea pig alveolar macrophages. These results indicate that the inhibitory effects of NIP-502 on bronchial responses are similar to those of prednisolone, but this compound seemed to act more selectively on the respiratory tract than prednisolone. Because of its effectiveness against a variety of bronchial responses, NIP-502 may be useful in the treatment of bronchial asthma.

Beta-adrenoceptor agonists interfere with glucocorticoid receptor DNA binding in rat lung

Inhaled beta 2-adrenoceptor agonists are the most effective bronchodilator treatment in asthma, yet paradoxically high doses may be associated with increased asthma morbidity and mortality. Steroids are the most effective therapy in controlling asthmatic inflammation and act by binding to specific sequences of DNA (GRE), thus modulating gene transcription. We report that in rat lung, the beta 2-adrenoceptor agonists, salbutamol and fenoterol, decrease the binding of glucocorticoid receptors to GRE, by 46 +/- 4% although it has no effect on the affinity or number of glucocorticoid receptors. The inhibition of GRE binding by salbutamol is concentration-dependent, can be blocked by propranolol and is seen following forskolin treatment. This effect appears to be due to an interaction between the glucocorticoid receptor and the transcription factor, cAMP response element binding protein (CREB), which is activated by high concentrations of beta 2-adrenoceptor agonists. We suggest that by this mechanism high doses of inhaled beta 2-adrenoceptor agonists may inhibit the anti-inflammatory effects of endogenous glucocorticoids and exogenous corticosteroids used for asthma therapy.

Effect of prolonged use of inhaled steroids on the cellular immunity of children with asthma

BACKGROUND

Systemic corticosteroids may affect the cellular immunity, but there is no available controlled data on such effects associated with a prolonged use of inhaled corticosteroids.

OBJECTIVE

The investigation was designed to study the effect of long-term inhaled beclomethasone dipropionate in daily doses of up to 600 micrograms on cellular immune functions.

METHODS

Twenty-four children with asthma treated with inhaled beclomethasone dipropionate for a mean of 22.6 months were compared with 16 children with asthma not treated with an inhaled steroid and with 20 healthy adults. Cellular immune parameters included differential white blood count, T- and B-cell numbers, T helper and suppressor counts, T-cell mitogenic transformation, and interleukin-1 and interleukin-2 secretion.

RESULTS

There was no difference in any of the studied cellular immune functions among the three study groups.

CONCLUSION

Long-term use of inhaled beclomethasone dipropionate by children with asthma, at daily doses of up to 600 micrograms, has no effect on certain parameters of cellular immunity.

Obstructive sleep apnea syndrome and bronchial hyperreactivity

This study was designed to investigate the prevalence of bronchial hyperreactivity (BH) in patients with obstructive sleep apnea syndrome (OSAS), heavy snorers, and light snorers; its correlation with OSAS severity; and its response to nasal CPAP therapy. Forty-eight age- and sex-matched subjects were selected on the basis of preentry sleep studies: Group I consisted of 16 patients with OSAS (hypopnea-apnea index (HAI) = 35 +/- 9); group II consisted of 16 cases of heavy snorers without OSAS; and group III, a control group, consisted of 16 subjects with only mild snoring. All 48 patients had normal pulmonary function (simple spirometry) prior to study entry and had no history of asthma or allergies. The prevalence of BH was prospectively assessed by giving each subject a methacholine challenge test (MCT). Patients with a positive MCT were treated with 2-3 months of nasal CPAP treatment, after which they had a second MCT. Four of 16 patients in group I had BH on MCT (PD20 = 88, 103, 109, 162 D.U.), whereas none of the group II or III subjects demonstrated BH. There was no correlation between BH and the severity of the OSAS. The 4 patients with BH in group I showed an increase in PD20M after 2-3 months of nasal CPAP treatment. In conclusion, BH may occur in patients with OSAS. It is unrelated to the severity of the OSAS, and nasal constant positive airway pressure (CPAP) therapy can decrease the hyperreactivity to methacholine in these patients.

Oral clonidine in patients with asthma: no significant effect on airway reactivity

Fifteen patients with asthma were randomized into a double-blind, placebo controlled, crossover trial evaluating whether clonidine increased airway resistance. After meeting entry criteria [demonstration of 20% improvement in any two of the following pulmonary function tests after bronchodilator therapy: FVC, FEV1, or forced expiratory flow over the mid-50% of the vital capacity(FEF(25-75)], patients were evaluated on two subsequent visits, receiving sequential doses of clonidine 0.1 mg (maximum cumulative dose 0.3 mg) or placebo in a random fashion. They returned to clinic after a 36-48 hour washout period at which time they received the opposite treatment. The end points were three doses of clonidine or placebo, decrease in blood pressure to < or = 90 mm mercury systolic, and/or < 70 mm mercury diastolic, or a 20% fall in FEV1. Airway reactivity was proved utilizing methacholine on each clinic visit, and blood pressures were monitored continuously during the study period. There were no significant differences in the provocative concentrations of methacholine inducing a 20% fall in FEV1 (PD20) between baseline (1.92), clonidine (1.10), and placebo (1.69). (Numbers in parentheses indicate PD20 values in cumulative dose units).

Budesonide treatment of moderate and severe asthma in children: a dose-response study

OBJECTIVE

The purpose of the study was to evaluate the dose-response relationships of the inhaled corticosteroid budesonide in a double blind crossover study in 19 children with moderate and severe asthma.

METHODS

A 2-week placebo treatment period (run-in) was followed by three 4-week treatment periods during which 100, 200, and 400 micrograms of budesonide were given per day in randomized order. Urinary cortisol excretion, lung functions, and protection against exercise-induced asthma were assessed at the end of run-in and each treatment period. Furthermore, morning and evening peak expiratory flow rates, day and night symptoms, and use of rescue beta 2-agonists were recorded throughout the study.

RESULTS

One hundred micrograms of budesonide per day markedly improved symptoms, morning and evening peak expiratory flow rates, and use of rescue beta 2-agonists (p < 0.01). No further improvement was seen in these parameters with increasing doses of budesonide. In contrast, a significant dose-response effect was found on lung functions measured at the hospital and fall in lung functions after exercise (p < 0.001); 200 micrograms was significantly better than 100 micrograms, and 400 micrograms was significantly better than 200 micrograms. About 53% of the maximum effect against exercise-induced asthma was achieved by the lowest budesonide dose (p < 0.001), and about 83% by the highest dose. No significant differences were seen in urinary cortisol excretion between run-in and the various budesonide doses.

CONCLUSIONS

Low doses of budesonide, which are not associated with any systemic side effects, have a marked antiasthma effect in children. Protection against exercise-induced asthma requires higher doses than achievement of symptom control.

Chronic asthma and chiropractic spinal manipulation: a randomized clinical trial

The purpose of this randomized patient- and observer-blinded cross-over trial was to evaluate the efficacy of chiropractic treatment in the management of chronic asthma when combined with pharmaceutical maintenance therapy. The trial was conducted at the National University Hospital's Out-patient Clinic in Copenhagen, Denmark. Thirty-one patients aged 18-44 years participated, all suffering from chronic asthma controlled by bronchodilators and/or inhaled steroids. Patients, or who had received chiropractic treatment for asthma within the last 5 years, who received oral steroids and immunotherapy, were not eligible. Patients were randomized to receive either active chiropractic spinal manipulative treatment or sham chiropractic spinal manipulative treatment twice weekly for 4 weeks, and then crossed over to the alternative treatment for another 4 weeks. Both phases were preceded and followed by a 2-week period without chiropractic treatment. The main outcome measurements were forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), daily use of inhaled bronchodilators, patient-rated asthma severity and non-specific bronchial reactivity (n-BR). Using the cross-over analysis, no clinically important or statistically significant differences were found between the active and sham chiropractic interventions on any of the main or secondary outcome measures. Objective lung function did not change during the study, but over the course of the study, non-specific bronchial hyperreactivity (n-BR) improved by 36% (P = 0.01) and patient-rated asthma severity decreased by 34% (P = 0.0002) compared with the baseline values.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of serum eosinophilic cationic protein as a marker of disease activity in chronic asthma

BACKGROUND

Serum eosinophil cationic protein (ECP) has been promoted as a direct marker of eosinophilic inflammation of the bronchi, especially helpful in patients with asymptomatic asthma.

OBJECTIVE

To evaluate serum ECP against indirect clinical markers of disease activity, we compared symptom score, bronchial obstruction, bronchial responsiveness, and blood eosinophil counts with serum ECP levels in children with symptomatic and asymptomatic chronic asthma and assessed ECP in others with allergic rhinitis alone.

METHODS

Twenty-four children with symptomatic asthma, 10 children with asymptomatic asthma, and 16 children with allergic rhinitis were studied. Measurements were made by standardized symptom questionnaire, spirometry, inhalation challenge with histamine or methacholine, blood eosinophil counts, and radioimmunoassay of serum ECP.

RESULTS

There was no difference in serum ECP levels between the symptomatic asthma, asymptomatic asthma, or rhinitis groups, and most values were within the normal range. Activated eosinophil counts were higher in subjects with symptomatic asthma than in those with asymptomatic asthma but not in subjects with rhinitis. Serum ECP correlated with eosinophil counts (p < 0.01) but not symptom score, forced expiratory volume in 1 second (FEV1), forced expiratory flow, mid-expiratory phase (FEF25-75), or provocative concentration causing a 20% fall in FEV1 (PC20). Symptom scores correlated with PC20 (p < 0.005) and FEF25-75 (p < 0.01).

CONCLUSION

Serum ECP is a poor indicator of disease activity in chronic asthma and cannot differentiate bronchial from nasal inflammation.

Modulation of bronchial inflammation: corticosteroids and other therapeutic agents

We have shown that treatment with inhaled corticosteroid acts to improve asthma-induced changes in the airway mucosa to such an extent that cell type and structure are normalized. More specifically, such treatment increases the number of intraepithelial nerves, decreases the total number of inflammatory cells, and eliminates epithelial eosinophils, as well as decreasing the number of endothelial gaps in the postcapillary venules. In contrast, these effects do not seem to be found following treatment with beta 2-agonists.

Meta-analysis of controlled trials of drug therapy in mild chronic asthma: the role of inhaled corticosteroids

OBJECTIVE

To determine the role of inhaled corticosteroids in the treatment of mild chronic asthma. SOURCE OF STUDIES: Searches of MEDLINE and Index Medicus for English language literature dealing with asthma and inhaled corticosteroids.

DESIGN

All retrieved articles were subjected to predetermined criteria for inclusion in the meta-analysis. Inclusion criteria centered around randomized, double-blind studies reporting objective clinical endpoint(s) for subjects with mild chronic asthma who were treated for more than seven days. Studies that were included were not allowed to have any predetermined exclusion criteria.

RESULTS

The literature search identified 129 articles, of which 41 satisfied some but not all of the criteria for inclusion. Five articles met all the criteria and were subjected to meta-analysis. The total number of subjects was 141. Peak expiratory flow rate (PEFR) was used as the objective endpoint for effect size calculation. Subjecting these five studies to quality review revealed a range of 0.607-0.741, with 1 as the highest attainable quality and 0 the lowest. Reported results for the different studies were found to be homogenous, thus allowing for the calculation of overall effect size. Inclusion of children in some of the studies added variance to the reported studies, but not to the point at which studies would be considered heterogenous. Effect sizes ranged between 0.41 and 0.89, and the overall weighted average effect size for PEFR was 0.59, with the calculated 95 percent confidence interval at 0.32 to 0.84. A tabulated display of binomial effect size for included trials provided ranges of success rates for treatment versus control values. Results of the studies were judged robust, as 92 studies reporting no significant effects are needed to turn the finding of the meta-analysis insignificant.

CONCLUSIONS

Based on the results of the meta-analysis, the existing literature suggests a role for inhaled corticosteroids in the treatment of mild chronic asthma.

Cellular and immunological markers of allergic and intrinsic bronchial asthma

Based on a growing body of evidence, allergic as well as intrinsic bronchial asthma have recently been defined as chronic persistent inflammatory disorders. Agreement has been reached that asthma can no longer be equated with bronchospasm only, and that the absence of reversibility of airflow obstruction does not exclude bronchial asthma. Bronchial hyperreactivity, on the other hand, although common to the vast majority of asthmatics, is not specific for bronchial asthma and provocation tests to measure bronchial hyperreactivity are not suited for routine monitoring of bronchial asthma. The clinical features of asthma are related to cellular as well as to soluble parameters of bronchial inflammation. Therefore, means of assessing and monitoring asthmatic inflammation have been investigated. Since eosinophils, T lymphocytes, mast cells, macrophages, neutrophils, epithelial cells, and structural cells, as well as various proinflammatory mediators and proteins, have been implicated in the pathogenesis of bronchial asthma, it has been anticipated that several of these cells or mediators might be either diagnostic of bronchial asthma or could serve as markers to monitor the underlying bronchial inflammation. Currently there is no diagnostic marker of bronchial asthma, which, on its own, either confirms or excludes bronchial asthma with appropriate sensitivity and specificity. Clinically the most reliable feature of bronchial asthma that seems to be related closely to the symptomatology still is the presence of eosinophils in peripheral blood, and especially in sputum. Eosinophil-derived products, particularly eosinophil granule proteins, have been investigated as markers of eosinophil participation in the pathogenesis of asthma and, comparable to eosinophil numbers themselves, are possible predictors of impending exacerbations of allergic, as well as intrinsic bronchial asthma. However, clinically their precise value in diagnosing and monitoring of bronchial asthma has not been documented convincingly and requires further investigation. Increasing data suggest that the regulation of eosinophilia is largely conveyed by interleukin-5 (IL-5) released from activated T-helper lymphocytes and possibly other cells. Therefore, T-lymphocyte activation, and especially assessment of systemic and local IL-5 levels, might be of diagnostic value and possibly useful in monitoring of inflammation in bronchial asthma in the future. A possible role and future applications for other markers of inflammation not related to eosinophils in monitoring or diagnosing bronchial asthma need to be established.

High affinity [3H]formoterol binding sites in lung: characterization and autoradiographic mapping

Agonist binding to the beta 2-adrenoceptors and its mapping were studied using the newly developed radioligand [3H]formoterol. The results of [3H]formoterol saturation binding and formoterol inhibition of [3H]formoterol binding were consistent with binding to a single class of receptors (Kd = 1.34 +/- 0.15 nM, Bmax = 154.9 +/- 8.0 fmol/mg protein in guinea pig lung membranes, n = 8; Kd = 1.05 +/- 0.17 nM, Bmax = 67.8 +/- 8.1 fmol/mg protein in human lung membranes, n = 5) and competition assays with other agonists and antagonists disclosed only a single class of site. The nonhydrolyzable GTP analogue GTP gamma S caused a reduction in both Kd and Bmax, indicating that the receptors labelled by [3H]formoterol are coupled to a guanine nucleotide binding regulatory protein. Receptor mapping of [3H]formoterol binding sites shows that beta 2-adrenoceptors were widely distributed in both guinea pig and human lung, with dense labelling over airway epithelium and uniformly over alveolar walls, and sparse labelling of airway and vascular smooth muscle. In addition, submucosal glands were also sparsely labelled in human bronchus. The distribution of beta 2-adrenoceptors was similar to the pattern previously described with non-selective radiolabelled antagonists in the presence of selective beta 1-adrenoceptor antagonists.

Reduction of morbidity in asthmatic children given a spacer device

STUDY OBJECTIVE

To evaluate whether providing a spacer device and a single, brief demonstration regarding its proper use would result in earlier resolution of asthma symptoms, improved school attendance, and decreased frequency of unscheduled medical visits for asthma among children receiving noncontinuous care in an urban emergency department (ED).

DESIGN

Randomized controlled trial.

SETTING

Urban hospital pediatric ED.

PARTICIPANTS

Eighty-four children with the chief complaint of asthma.

INTERVENTION

Children were enrolled in the ED at the time of an asthma attack and randomly assigned to one of two treatment groups. The spacer group received an inhaled beta-agonist at discharge from the ED with a spacer device. The control group received inhaled or oral beta-agonists without a spacer device. Both groups received other medications at the discretion of the evaluating physician who was not the interviewer in any case. A baseline questionnaire was completed and follow-up by telephone was done at 1 week, and 2, 4, and 6 months after enrollment.

MEASUREMENTS AND RESULTS

The spacer group reported significantly earlier resolution of wheezing (0 days vs 2 days, p < 0.01) at the 2- and 4-month follow-up assessments. They reported significantly fewer days of cough after an asthma attack at 2 months (1 day vs 3 days, p < 0.01) and 4 months (0 days vs 3 days, p < 0.01). The spacer group missed significantly fewer days of school following an asthma attack at 2 and 4 months (0 days vs 2 days, p = 0.05). There was no difference between the two groups on any outcome measures at the 1-week and 6-month follow-up assessments.

CONCLUSIONS

Introducing a spacer device to patients in a busy, inner-city pediatric ED is an effective and efficient intervention that improves the functioning of asthmatic children in terms of resolution of cough and wheeze and school absenteeism.

Inhibitory effects of theophylline, terbutaline, and hydrocortisone on leukotriene B4 and C4 generation by human leukocytes in vitro

Leukotriene B4 (LTB4) and leukotriene C4 (LTC4) are considered to be important mediators in the pathophysiology of asthma. Theophylline, terbutaline, and hydrocortisone are drugs commonly used in the treatment of asthma. In the present study we have investigated the in vitro inhibitory effects of theophylline, terbutaline, and hydrocortisone on LTB4 and LTC4 generation from human leukocytes. After preincubation in the presence of these drugs, the cells were stimulated with the calcium ionophore A 23187 and the supernatants were analyzed for their LTB4 and LTC4 content using reverse-phase high-performance liquid chromatography (HPLC). Total leukotriene (LT) production (the combined amounts of LTB4 and LTC4) was dose-dependently inhibited by pretreatment with theophylline, terbutaline or hydrocortisone. Therapeutic levels of hydrocortisone (5 x 10(-6) M) plus theophylline (5 x 10(-5) M) inhibited LTB4 and LTC4 production in an additive way, as did the combination of hydrocortisone plus terbutaline (5 x 10(-8) M). A statistically significant effect of diminished LTB4 generation was obtained after preincubation with therapeutic levels of theophylline plus terbutaline, but no such effect was seen for LTC4 levels. The in vitro inhibitory effects on LTB4 and LTC4 generation from human leukocytes by theophylline, terbutaline, and hydrocortisone, as well as the additive effect of hydrocortisone plus theophylline or terbutaline, add to our understanding of the therapeutic effects of these drugs in the treatment of bronchopulmonary obstruction.

Comparison between sodium cromoglycate (MDI: metered-dose inhaler) and beclomethasone dipropionate (MDI) in treatment of adult patients with mild to moderate bronchial asthma. A double-blind, double-dummy randomized, parallel-group study

This study compared the efficacy and tolerability of sodium cromoglycate (SC) and beclomethasone dipropionate (BDP) in adult patients with bronchial asthma inadequately treated with bronchodilators alone. The study was a double-blind, randomized, double-dummy, parallel-group study. Patients with mild to moderate symptomatic asthma, inadequately treated with bronchodilators only, were, after a 2-week run-in (base-line) period, randomized to 8 weeks of treatment with either SC 10 mg four times daily or BDP 100 micrograms four times daily. Salbutamol metered-dose inhaler was given as relief medication. A total of 37 patients were randomized for treatment, 19 patients in the SC group and 18 patients in the BD group. Efficacy and safety were determined by daily record card data: morning and evening peak-expiratory-flow rates (PEFR), daytime and nighttime asthma symptom scores, and rescue salbutamol use. At clinic visits, FEV1 and FVC were measured, as were the physician's and the patient's assessment of the medication at the end of the study. The safety and tolerability of the trial medication were assessed by monitoring adverse events throughout the study. A clinically and statistically significant improvement of the asthma in FEV1, symptom scores, rescue medication, and global opinion of efficacy was observed, and both groups provided equivalent efficacy. The morning PEFR as well as the evening PEFR for both groups improved, but was statistically significant only for the BDP group (M-PEFR). Both drugs were well tolerated with only a few minor adverse events. This trial shows that SC and BDP are equally effective anti-inflammatory treatments for mild to moderate bronchial asthma in adults.

Cytokine regulation of low-affinity IgE receptor (CD23) on monocytes from asthmatic subjects

The regulation of CD23 expression (Fc epsilon RII) by cytokines on monocytes from normal subjects, asymptomatic and acute asthmatics was investigated. CD23 was weakly expressed on cells from controls, but was significantly enhanced in the two groups of asthmatics. The addition of IL-4 on monocytes induced an increase of CD23 expression in cells from controls and asthmatics. Interferon-gamma (IFN-gamma) did not modulate CD23 expression in asthmatics or control subjects, while high doses of IL-6 (2000 U/ml) enhanced CD23 expression on cells from asthmatics or controls. In vitro stimulation of monocytes with Timothy grass pollen allergen did not enhance CD23 receptor in asthmatics with a positive skin test to this pollen. We speculate that CD23 expression in asthmatics is markedly enhanced by Th2-dependent cytokines, such as IL-4 and IL-6. Thus, the regulation of Th2 cell activation by anti-cytokine therapy could have an important effect on the down-regulation of CD23 on monocytes, and in shifting a Th2 subpopulation into a Th1 subpopulation by blocking Th2-dependent cytokines.

Does beclomethasone dipropionate suppress dehydroepiandrosterone sulphate in postmenopausal women?

BACKGROUND

Patients with chronic obstructive airways disease and asthma are at special risk of developing osteoporosis. Previous research has indicated that adrenal androgen levels in postmenopausal women are suppressed by short term high dose inhaled corticosteroids. Such an effect, if sustained, may be a causative factor for long term bone loss. We tested the hypothesis that postmenopausal women receiving > or = 1 mg/day inhaled beclomethasone dipropionate, long term, have suppressed dehydroepiandrosterone sulphate levels when compared to postmenopausal controls.

METHODS

As part of a larger study, we studied 36 postmenopausal subjects, recruited from regional pharmacies and a hospital chest clinic, who had been receiving treatment for asthma. Subjects were selected if they were receiving > or = 1 mg/day inhaled beclomethasone dipropionate (n = 27) or receiving no beclomethasone dipropionate (n = 9). The two groups were compared for dehydroepiandrosterone sulphate levels, age and potential confounders.

RESULTS

Mean dehydroepiandrosterone sulphate levels were 35% lower in the high dose beclomethasone dipropionate group than the control group (p < 0.01).

CONCLUSIONS

This is the first report of suppression of dehydroepiandrosterone sulphate in postmenopausal women receiving long term inhaled beclomethasone dipropionate. Further research is needed to clarify whether or not there is any associated clinically important adverse effect on bone density.

Therapeutic controversies in the treatment of asthma

OBJECTIVE

To introduce readers to the current controversial topics in the area of asthma therapy. Background is provided such that clinicians are aware of these issues and can make rational decisions.

DATA SOURCES

Pertinent articles were individually identified and reviewed from each journal.

STUDY SELECTION

Relevant studies, determined by topic and other specific criteria, e.g., testing methodology, were included.

DATA SYNTHESIS

Further investigation is required in the areas discussed. Systemic effects, specifically growth suppression (in children), adrenal suppression, and osteoporosis, have been demonstrated with high-dose inhaled glucocorticoids; however, the clinical relevance of such intravenous glucocorticoid formulations via nebulizer have not been demonstrated. Likewise, data on the equivalence of the inhaled glucocorticoids, with regard to efficacy and potential systemic effects, and the differences between metered-dose inhalers and dry powder inhalers, with regard to aerosol characteristics and drug delivery, are unclear. Theophylline, when used with inhaled beta-adrenergic agonists and systemic glucocorticoids for the treatment of acute asthma, as not been shown to provide clear benefit and may result in increased adverse effects. The use of regular (vs. "as needed" or prn) inhaled beta-adrenergic agonists, although shown in two studies to be detrimental to the control of asthma and result in an increased risk of death or near death caused by asthma, has not been conclusively demonstrated to be harmful.

CONCLUSIONS

Monitoring for adverse effects and the use of techniques to minimize systemic absorption (spacers and mouth rinsing) are recommended when high-dose inhaled glucocorticoid therapy is used. Intranasal and intravenous glucocorticoid products are not recommended for administration via nebulizer because of safety concerns. Until further data are available, inhaled glucocorticoids are thought to be equivalent on a microgram-per-microgram basis rather than an actuation-per-actuation basis. Theophylline is no longer recommended for treatment of acute exacerbations in nonhospitalized patients not already receiving the medication, and the link between deterioration of asthma control (and the risk for death) and regular inhaled beta-adrenergic agonists appears weak.

Effects of chronic airway inflammation on the activity and enzymatic inactivation of neuropeptides in guinea pig lungs

The effects of airway inflammation induced by chronic antigen exposure on substance P (SP)-induced increases and vasoactive intestinal peptide (VIP)-induced decreases in airway opening pressure (Pao), and the recovery of intact and hydrolyzed radiopeptide were studied in tracheally perfused guinea pig lungs. SP (10(-6) mol/kg) induced a significantly greater increase in Pao in lungs from antigen-exposed (30 +/- 5 cm H2O) than saline-exposed animals (15 +/- 1 cm H2O, P < 0.05). Significantly more intact 3H-SP and significantly less 3H-SP 1-7, a neutral endopeptidase (NEP) hydrolysis product, were recovered from the lung effluent of antigen-exposed than saline-exposed animals (P < 0.05). Injection of VIP (10(-9) mol/kg) induced significantly more pulmonary relaxation in saline-exposed compared with antigen-exposed lungs (62 +/- 4%, P < 0.001). In contrast to effluent from saline-exposed animals, lung effluent from antigen-exposed lungs contained less intact VIP, increased amounts of a tryptic hydrolysis product, and no products consistent with the degradation of VIP by NEP. These data indicate that inflamed lungs are more sensitive to the contractile effects of SP because it is less efficiently degraded by NEP and are less sensitive to the relaxant effects of VIP because it is more efficiently degraded by a tryptic enzyme. Changes in airway protease activity occur with allergic inflammation and may contribute to airway hyperresponsiveness.

Pharmacokinetic optimisation of asthma treatment

Asthma is generally managed with bronchodilator therapy and/or anti-inflammatory drugs. Guidelines now advocate selection of drugs and pharmaceutical formulations (long-acting vs short-acting, inhaled vs systemic) on the basis of disease severity. Theophylline has a narrow therapeutic margin. Clearance is highly variable and plasma concentrations should be monitored to avoid the occurrence of plasma concentration-related adverse effects. The rate of absorption of theophylline differs depending on the sustained release formulation administered. Some products do not provide sufficient plasma drug concentrations for therapeutic efficacy over a 12-hour period, particularly in patients with high clearance rates (e.g. children and patients who smoke). Administration of drugs via inhalation offers several advantages over systemic routes of administration (e.g. adverse effects are decreased). Inhalation is now advocated as first-line therapy. Aerosol medications available for the treatment of asthma are beta 2-agonist (including the newer long-acting agents such as salmeterol), corticosteroids, anticholinergic drugs, sodium cromoglycate (cromolyn sodium) and nedocromil. To reach the airways, aerosolised particles should be 1 to 5 microns in diameter. Particles of this size can be produced by nebuliser for continuous administration or by metered-dose inhaler and drug powder inhaler for unit dose medication. For efficient use of the metered-dose inhaler, slow inhalation and actuation must be coordinated. However, efficacy and convenience can be improved when spacer devices are used. Furthermore, spacer devices lessen the oropharyngeal adverse effects of inhaled corticosteroids. Dry powder inhalers are more easily used by children and elderly patients than metered-dose inhalers. Regardless of the device used, a maximum of 10% of the inhaled dose reaches the airways. The rest of the dose is swallowed and absorbed through the gastrointestinal tract. Most inhaled drugs have low oral bioavailability, either because of a high first-pass metabolism (beta 2-agonists and glucocorticoids) or because of lack of absorption (sodium cromoglycate). Sulphation of beta 2-agonists occurs in the wall of the gastrointestinal tract and extensive metabolism of inhaled corticosteroids occurs in the liver. Low bioavailability of the swallowed fraction contributes to reduced adverse effects. The pharmacokinetic properties of an inhaled drug are of interest. The fraction of the dose absorbed through the lung has the same disposition characteristics as an intravenous dose, and the swallowed fraction has the same disposition as an orally administered dose. However, for many drugs, pharmacokinetic data after inhalation are limited and cannot be used as a criteria for selection of therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Changing strategies in the management of asthma

Mortality from asthma is apparently on the rise and, in some cases, may be due to the type and amount of medication used by the patient. As a result, the role of some commonly prescribed agents has changed in recent years. In this article, the authors review modifications in the use of currently available drugs, discuss new applications of drugs not traditionally used for asthma, and examine the rationale behind the development of entirely new classes of drugs.

Effect of dexamethasone on A23187-induced airway responses in the guinea pig

We examined the effect of dexamethasone on A23187-induced bronchospasm, pulmonary inflammation and airway responses to substance P. Guinea pigs, dosed orally once a day for 4 days with dexamethasone (3.0, 10.0 or 30.0 mg/kg) or saline, were exposed to an aerosol of A23187 for 12 min or until labored breathing began. Postmortem pulmonary gas trapping was used as an indicator of in vivo airway obstruction and changes in bronchial responses. Dexamethasone did not alter airway obstruction or inflammation 1 h after A23187 exposure. However, dexamethasone reduced the enhanced airway responses to substance P and bronchiolar/peribronchiolar inflammation 24 h post-A23187. It is possible that glucocorticosteroid suppression of A23187-induced pulmonary inflammation was important in reducing the increased airway responses to substance P.

Granulocyte-macrophage colony-stimulating factor stimulates macrophages to respond to IgE via the low affinity IgE receptor (CD23)

We have found increased concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF) in the bronchoalveolar lavage fluid of 11 patients with nocturnal asthma (15.3 +/- 4.6 pg/ml) compared with normal subjects (2.3 +/- 6.1 pg/ml) (p = 0.03). In contrast to patients with asthma, low affinity IgE receptors (Fc epsilon RII or CD23) are not expressed on monocytes obtained from healthy, nonatopic donors. Fc epsilon RII expression was induced by the cytokines GM-CSF and interleukin (IL)-4 either alone or in combination. As assessed by flow cytometry, the combination of IL-4 and GM-CSF was found to be synergistic, inducing up to 54.8% +/- 4.6% Fc epsilon RII-positive monocytes compared with a maximum of 27.4% +/- 5.0% and 30.0% +/- 4.0% with IL-4 and GM-CSF alone, respectively (p < 0.05 compared with either cytokine alone). Human monocytes from the peripheral blood of seven normal subjects were cultured for 24 hours with and without IL-4 or GM-CSF. With IL-4, addition of IgE/anti-IgE complexes failed to induce IL-1 secretion and inhibited IL-1 secretion induced by lipopolysaccharides. The addition of GM-CSF or IgE immune complexes alone resulted in no additional IL-1 secretion in supernatants of the untreated monocytes, whereas the IgE complexes did stimulate IL-1 secretion by monocytes cultured in GM-CSF, as measured by ELISA (from 0.7 +/- 0.2 ng/ml to 2.3 +/- 0.5 ng/ml; p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Physiological changes due to age. Implications for respiratory drug therapy

The pulmonary system is modified in various ways over time and it is particularly vulnerable to environmental insults. Of particular interest are the implications of aging for therapy of respiratory illnesses. The changes in pulmonary structure and function due simply to aging, and changes due to diseases, should be distinguished from each other. The great reserve function of the lung permits reasonable physical capacity in healthy individuals despite aging changes. In principle, loss of function equivalent to more than one lung is necessary to impair aerobic capacity at any age. Elderly people are subject to the same respiratory diseases as younger adults but may manifest them differently. They may present in atypical ways such as in bacterial pneumonia, tuberculosis, and asthma, all modified by anatomical alterations or deterioration of immunological defence mechanisms. Accumulation of toxic substances over time such as cigarette smoke or environmental pollutants may give rise to chronic bronchitis, emphysema, bronchogenic carcinoma and interstitial lung disease. Changes in the number or function of airway receptors modulate responses to bronchodilator drugs. Chronic inflammation of the bronchial wall has blurred the distinction between traditional asthma and chronic bronchitis and emphysema, and similar drug therapy can be useful for all. Adverse reactions to respiratory drugs such as theophylline, oral corticosteroids, and isoniazid increase with age. As more data accumulate, drug therapy of respiratory diseases in older patients will become more effective and safer.

[Current bronchodilator strategies in the treatment of asthma]

The drugs used in asthma must act on the two major mechanisms of the disease: bronchial obstruction and inflammation of the airways. Two main classes of drugs are available to reach these targets: bronchodilators, headed by beta 2-stimulants, and anti-inflammatory drugs of the corticosteroid family. Bronchodilatation obtained with beta 2-stimulants is the first and most effective treatment of asthma. These drugs are usually administered by inhalation: metered-dose aerosols with or without inhalation chambers, or nebulization for severe asthma. Very high doses can be used without fear of side-effects, the principal objective of this treatment being to relieve bronchial obstruction. In the absence of rapid and lasting improvement, bronchodilators must always be combined with corticosteroids. In all cases medical supervision immediately following the asthma attack is necessary and the patient should subsequently be placed under the care of pneumologists.

Exercise induced asthma: a clinical perspective

Exercise is a very common precipitant of asthma. Inflammation and edema are felt to be important components of the asthmatic response. Heat and water loss from the airway mucosa are most likely important in its pathogenesis, although the exact etiology remains unknown. A good history combined with proper diagnostic testing can usually determine the diagnosis, and prevention is the key to effective management. Although modified training techniques are often helpful, medications are usually needed for both prevention and treatment. While antiinflammatory agents are gaining therapeutic importance, inhaled beta-agonists remain the treatment of choice. With appropriate diagnosis and management, exercise-induced asthma should not limit participation nor performance in athletics for the great majority of the population.

Clinical features to predict hypoxia and/or hypercapnia in acute asthma attacks

Arterial blood gas data were correlated with clinical variables including patients' perception of dyspnea and spirometry in 79 episodes of acute asthma attacks. Among several variables that showed univariate significance with severity, only subjective degree of dyspnea rated on a modified Borg scale (MBS) remained predictive to discriminate the presence or absence of hypoxia/hypercapnia in multivariate analyses. MBS alone could predict the arterial blood gas status with accuracy of approximately 75%. Therefore, patients' sensation of dyspnea seemed to be an important factor in the evaluation of acute asthma in an emergency room.