Comparison of the anti-inflammatory properties of formoterol, salbutamol and salmeterol in guinea-pig skin and lung

Inhaled β2 Adrenergic Agonists and Other cAMP-Elevating Agents: Therapeutics for Alveolar Injury and Acute Respiratory Disease Syndrome?

Inhaled long-acting β-adrenergic agonists (LABAs) and short-acting β-adrenergic agonists are approved for the treatment of obstructive lung disease via actions mediated by β2 adrenergic receptors (β2-ARs) that increase cellular cAMP synthesis. This review discusses the potential of β2-AR agonists, in particular LABAs, for the treatment of acute respiratory distress syndrome (ARDS). We emphasize ARDS induced by pneumonia and focus on the pathobiology of ARDS and actions of LABAs and cAMP on pulmonary and immune cell types. β2-AR agonists/cAMP have beneficial actions that include protection of epithelial and endothelial cells from injury, restoration of alveolar fluid clearance, and reduction of fibrotic remodeling. β2-AR agonists/cAMP also exert anti-inflammatory effects on the immune system by actions on several types of immune cells. Early administration is likely critical for optimizing efficacy of LABAs or other cAMP-elevating agents, such as agonists of other Gs-coupled G protein-coupled receptors or cyclic nucleotide phosphodiesterase inhibitors. Clinical studies that target lung injury early, prior to development of ARDS, are thus needed to further assess the use of inhaled LABAs, perhaps combined with inhaled corticosteroids and/or long-acting muscarinic cholinergic antagonists. Such agents may provide a multipronged, repurposing, and efficacious therapeutic approach while minimizing systemic toxicity. SIGNIFICANCE STATEMENT: Acute respiratory distress syndrome (ARDS) after pulmonary alveolar injury (e.g., certain viral infections) is associated with ∼40% mortality and in need of new therapeutic approaches. This review summarizes the pathobiology of ARDS, focusing on contributions of pulmonary and immune cell types and potentially beneficial actions of β2 adrenergic receptors and cAMP. Early administration of inhaled β2 adrenergic agonists and perhaps other cAMP-elevating agents after alveolar injury may be a prophylactic approach to prevent development of ARDS.

Effects of β2-adrenergic agonists on house dust mite-induced adhesion, superoxide anion generation, and degranulation of human eosinophils

Background

Even in subjects who are not sensitized to house dust mite (HDM), allergic symptoms can be clinically aggravated by exposure to dust. We previously reported that Dermatophagoides farinae (Df), an important HDM, or Der f 1, a major allergen of Df, induced the effector functions of eosinophils, which may be an important mechanism for HDM-induced symptoms in nonsensitized patients. In a clinical setting, β2-adrenergic agonists, such as salbutamol and formoterol, are used for the treatment of asthma attacks or exacerbation to release the airway obstruction. Several reports have suggested that some β2-adrenergic agonists have an anti-inflammatory capacity.

Objective

In this study, we investigated whether β2-adrenergic agonist could modify the Df- or Der f 1-induced activation of eosinophils.

Methods

Blood eosinophils obtained from healthy donors were preincubated with either formoterol (1 μM), salbutamol (1 μM), or buffer control and then stimulated with Df extract (1 μg/mL) or Der f 1 (100 pg/mL). Eosinophil adhesion to intercellular adhesion molecule (ICAM)-1 was measured using eosinophil peroxidase assays. Generation of superoxide anion (O₂ ^-) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) concentrations in cell media were measured by enzyme-linked immunosorbent assay.

Results

Formoterol, but not salbutamol, suppressed the Df- or Der f 1-induced eosinophil adhesion to ICAM-1. Furthermore, formoterol, but not salbutamol, suppressed Df-induced O₂ ^- generation or EDN release. Neither formoterol nor salbutamol suppressed spontaneous eosinophil adhesion, O₂ ^- generation, or EDN release.

Conclusion

These findings suggested that formoterol, but not salbutamol, suppressed Df- or Der f 1-induced eosinophil activation when used at the same concentration. Therefore, formoterol could potentially be used for the treatment of bronchial asthma via both bronchodilation and anti-inflammatory effect.

Echinacea complex--chemical view and anti-asthmatic profile

ETHNOPHARMACOLOGICAL RELEVANCE

Echinacea purpurea (L.) Moench is one of the mostly used herbs in the traditional medicine for the treatment of respiratory diseases. Modern interest in Echinacea is directed to its immunomodulatory activity. Recent studies have shown that secretion of asthma-related cytokines in the bronchial epithelial cells can be reversed by Echinacea preparations.

AIM OF THE STUDY

To examine the pharmacodynamics profile of Echinacea active principles, a complex has been isolated from its flowers by alkaline extraction and has been tested using an animal model of allergic asthma.

MATERIAL AND METHODS

The structural features of Echinacea purpurea complex was determined using chemical and spectroscopic methods. Allergic inflammation of the airways was induced by repetitive exposure of guinea pigs to ovalbumin. Echinacea complex was then administered 14 days in 50mg/kg b.w. daily dose perorally. Bronchodilatory effect was verified as decrease in the specific airway resistance (sRaw) in vivo and by reduced contraction amplitude (mN) of tracheal and pulmonary smooth muscle to cumulative concentrations of acetylcholine and histamine in vitro. The impact on mucociliary clearance evaluated measurement of ciliary beat frequency (CBF) in vitro using LabVIEW™ Software. Anti-inflammatory effect of Echinacea complex was verified by changes in exhaled NO levels and by Bio-Plex® assay of Th2 cytokine concentrations (IL-4, IL-5, IL-13 and TNF-alpha) in serum and bronchoalveolar lavage fluid (BALF).

RESULTS

Chemical and spectroscopic studies confirmed the presence of carbohydrates, phenolic compounds and proteins, as well as the dominance of rhamnogalacturonan and arabinogalactan moieties in Echinacea complex. The significant decrease in sRaw values and suppressed histamine and acetylcholine-induced contractile amplitude of isolated airways smooth muscle that were similar to effects of control drug salbutamol confirmed Echinacea complex bronchodilatory activity. The anti-inflammatory effect was comparable with that of control agent budesonide and was verified as significantly reduced exhaled NO levels and concentration of Th2 cytokines in serum and BALF. The values of CBF were changed only insignificantly on long-term administration of Echinacea complex suggested its minimal negative impact on mucociliary clearance.

CONCLUSION

Pharmacodynamic studies have confirmed significant bronchodilatory and anti-inflammatory effects of Echinacea complex that was similar to effects of classic synthetic drugs. Thus, results provide a scientific basis for the application of this herb in traditional medicine as a supplementary treatment of allergic disorders of the airways, such as asthma.

Effect of beta2-adrenergic agonists on eosinophil adhesion, superoxide anion generation, and degranulation

BACKGROUND

Eosinophils play important roles in the development of asthma exacerbation. Viral infection is a major cause of asthma exacerbation, and the expression of IFN-γ-inducible protein of 10 kDa (IP-10) and cysteinyl leukotrienes (cysLTs) is up-regulated in virus-induced asthma. As β2-adrenergic agonists, such as formoterol or salbutamol, are used to treat asthma exacerbation, we examined whether formoterol or salbutamol could modify eosinophil functions such as adhesiveness, particularly those activated by cysLTs or IP-10.

METHODS

Eosinophils were isolated from the blood of healthy subjects and were pre-incubated with either formoterol or salbutamol, and subsequently stimulated with IL-5, LTD4, or IP-10. Adhesion of eosinophils to intercellular cell adhesion molecule (ICAM)-1 was measured using eosinophil peroxidase assays. The generation of eosinophil superoxide anion (O2(-)) was examined based on the superoxide dismutase-inhibitable reduction of cytochrome C. Eosinophil-derived neurotoxin (EDN) release was evaluated by ELISA as a marker of degranulation.

RESULTS

Neither formoterol nor salbutamol suppressed the spontaneous adhesion of eosinophils to ICAM-1. However, when eosinophils were activated by IL-5, LTD4, or IP-10, formoterol, but not salbutamol, suppressed the adhesion to ICAM-1. Formoterol also suppressed IL-5, LTD4, or IP-10 induced eosinophil O2(-) generation or EDN release.

CONCLUSIONS

These findings suggest that formoterol, but not salbutamol, suppresses eosinophil functions enhanced by IL-5, LTD4, or IP-10. As these factors are involved in the development of asthma exacerbation, our results strongly support the hypothesis that administration of formoterol is a novel strategy for treating asthma exacerbation.

Bronchodilators, receptors and cross-talk: Together is better?

The most widely used maintenance therapies in chronic obstructive pulmonary disease (COPD) are long-acting muscarinic antagonists (LAMAs), and a number of these drugs are now available in combination with long-acting β2-agonists (LABAs). LAMAs inhibit the parasympathetic muscarinic pathway, while LABAs, as sympathomimetics, reduce airway smooth muscle (ASM) tone. As well as directly controlling the constriction and relaxation of ASM, muscarinic and adrenergic receptors are found on inflammatory cells, and drugs that target these receptors may also reduce inflammation in COPD. Evidence suggests that the muscarinic and adrenergic pathways cross-talk at the level of neuronal input to the ASM via second-messenger pathways within ASM cells. Although the cross-talk is not completely understood, pharmacologically targeting both pathways in COPD can maximize bronchodilation. Combining LAMAs and LABAs demonstrated improved efficacy compared with the individual therapies and so, for greater convenience, several fixed-dose combinations for once-daily use have been developed. These fixed-dose combinations demonstrate improvements in both lung-function and patient-reported outcomes compared with well-established monotherapies, with similar tolerability profiles to the individual agents.

Comparing clinical efficacy of Symbicort versus Pulmicort in reducing asthma symptom and improving its control

Background:

Recently, higher efficacy of the combination of long-acting beta2-adrenoceptor agonist and inhaled corticosteroids on controlling asthma symptoms has been hypothesized. This study aimed to examine the clinical effects of the combination of Budesonide with formoterol (Symbicort) and Budesonide (Pulmicort) alone in persistent asthma.

Materials and Methods:

In a randomized double-blinded clinical trial, 76 patients with definite diagnosis of moderate-to-severe asthma were randomized to receive Pulmicort 180 mcg/inhalation two puffs twice daily, or receive Symbicort 80/4.5 mg/inhalation two puffs twice daily, or receive Symbicort 160/4.5 mg/inhalation two puffs twice daily for 3 months. All participants were initially evaluated by spirometry for assessing respiratory parameters and also the level of asthma control was assessed by Asthma Control Test (ACT).

Results:

More significant improvement in spirometry parameters, including forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), FEV1/FVC ratio, as well as in peak expiratory flow (PEF) in both groups of Symbicort with the regimens 80/4.5 mg/inhalation or 160/4.5 mg/inhalation 2 puffs twice daily compared with Pulmicort group, ACT score was significantly improved in Symbicort group with the regimens 160/4.5 mg/inhalation compared with both Symbicort groups with lower dosage and Pulmicort group. Response to treatment in PEF parameter and also in ACT level was significantly more in those who received Symbicort with the regimens 160/4.5 mg/inhalation compared with other two interventional groups adjusted for gender and age.

Conclusion:

Symbicort with the regimens 160/4.5 mg/inhalation has higher efficacy in reducing asthma symptom and improving its control compared with low doses of this drug and with Pulmicort.

Inhaled Salmeterol/Fluticasone Propionate Combination in Chronic Obstructive Pulmonary Disease

Salmeterol/fluticasone propionate is a fixed-dose combination of the long-acting beta2-adrenoceptor agonist salmeterol and the corticosteroid fluticasone propionate and is inhaled via the Diskus powder inhaler. In three randomized, double-blind, 24-week or 52-week studies in >2850 patients with chronic obstructive pulmonary disease (COPD), administration of salmeterol/fluticasone propionate 50/250 microg twice daily (in one study) and salmeterol/fluticasone propionate 50/500 microg twice daily (in the other studies) provided greater improvement in lung function than placebo or either component alone at the same nominal dosage. Both strengths of the combination product administered twice daily resulted in clinically meaningful increases in scores in health-related quality-of-life questionnaires that were specific for respiratory disease. Improvements in this and almost all other secondary measures of efficacy, including symptomatic outcomes, were significantly greater with the combination product than with placebo. Administration of salmeterol/fluticasone propionate as a combination product did not result in any untoward interactions that affected the pharmacodynamic, pharmacokinetic or tolerability profiles of the individual components. Candidiasis, hoarseness/dysphonia, throat irritation and headache occurred more frequently with salmeterol/fluticasone propionate than with placebo in patients with COPD.

Effects of budesonide/formoterol combination therapy versus budesonide alone on airway dimensions in asthma

BACKGROUND AND OBJECTIVE

Combination therapy with inhaled corticosteroids and long-acting β(2)-agonists results in improved asthma symptom control compared with the use of inhaled corticosteroids alone. However, the effects of combination therapy on structural changes and inflammation of the airways are still unknown. The aim of this study was to compare the effects of budesonide/formoterol with those of budesonide alone on airway dimensions and inflammation in individuals with asthma.

METHODS

Fifty asthmatic patients were randomized to treatment with budesonide/formoterol (200/6 µg, two inhalations bd) or budesonide (200 µg, two inhalations bd) for 24 weeks. Airway dimensions were assessed using a validated computed tomography technique, and airway wall area (WA) corrected for body surface area (BSA), percentage WA (WA%), wall thickness/Ösquare root BSA, and luminal area (Ai)/BSA at the right apical segmental bronchus, were measured. The percentage of eosinophils in induced sputum, pulmonary function, and Asthma Quality of Life Questionnaires (AQLQ) were also evaluated.

RESULTS

There were significantly greater decreases in WA/BSA (P < 0.05), WA% (P < 0.001) and wall thickness/square root BSA (P < 0.05), and increases in Ai/BSA (P < 0.05), in subjects treated with budesonide/formoterol compared with those treated with budesonide. The reduction in sputum eosinophils and increase in per cent of predicted forced expiratory volume in 1 s (FEV(1) %) were greater for subjects treated with budesonide/formoterol compared with those treated with budesonide alone. In the budesonide/formoterol group, the changes in WA% were significantly correlated with changes in sputum eosinophils and FEV(1%) (r = 0.84 and r = 0.64, respectively). There were improvements in the AQLQ scores after treatment with budesonide/formoterol.

CONCLUSIONS

Budesonide/formoterol combination therapy is more effective than budesonide alone for reducing airway wall thickness and inflammation in individuals with asthma.

Anti-inflammatory effects of β2 adrenergic receptor agonists in experimental acute lung injury

These studies were undertaken to extend emerging evidence that β(2) adrenergic receptor (β(2)AR) agonists, in addition to their bronchorelaxing effects, may have broad anti-inflammatory effects in the lung following onset of experimental acute lung injury (ALI). Young male C57BL/6 mice (25 g) developed ALI following airway deposition of bacterial LPS or IgG immune complexes in the absence or presence of appropriate stereoisomers (enantiomers) of β(2)AR agonists, albuterol or formoterol. Endpoints included albumin leak into lung and buildup of polymorphonuclear neutrophils and cytokines/chemokines in bronchoalveolar fluids. Both β(2)AR agonists suppressed lung inflammatory parameters (IC(50)=10(-7) M). Similar effects of β(2)AR agonists on mediator release were found when mouse macrophages were stimulated in vitro with LPS. The protective effects were associated with reduced activation (phosphorylation) of JNK but not of other signaling proteins. Collectively, these data suggest that β(2)AR agonists have broad anti-inflammatory effects in the setting of ALI. While β(2)AR agonists suppress JNK activation, the extent to which this can explain the blunted lung inflammatory responses in the ALI models remains to be determined.

Fluticasone propionate and Salmeterol combination induces SOCS-3 expression in airway epithelial cells

Fluticasone propionate (FP) and Salmeterol (SAL) are commonly used in combination therapy for patients with Chronic obstructive pulmonary disease (COPD). Clinical studies show that FP/SAL used in combination therapy was found to inhibit airway inflammation in COPD patients. However, the mechanisms associated with FP/SAL induced anti-inflammatory effects were not clear. We have evaluated the effect of FP/SAL and tobacco smoke (TS) on SOCS-3 and interleukine-6 expression in bronchial airway epithelial cells (BAEpCs). Human BAEpCs were exposed to TS and subsequently treated with FP or SAL alone or in combinations in the presence and absence of mitogen activated protein kinase (MAPK) inhibitors for either Erk1/Erk2, or p38 or PI3 kinase. In BAEpCs, TS induced IL-6 expression via ERK1/ERK2 MAPK pathway and FP/SAL inhibited TS mediated IL-6 expression. TS down regulated the SOCS-3 expression via activation of Erk1/Erk2, and p38 MAPK signaling. When TS exposed BAEpCs were treated with FP/SAL SOCS-3 expression was restored. FP/SAL combinations induced significantly higher expression of SOCS-3 in BAEpCs when compared to individual drug. Pretreatment with Ly294002 a PI3 MAPK inhibitor significantly attenuated FP/SAL induced SOCS-3 expression in BAEpCs. Furthermore, FP/SAL blunted TS induced phosphorylation of Erk1/Erk2 and p38 MAPK in BAEpCs. Our study suggests that TS inhibits SOCS-3, combination of FP/SAL has a profound synergistic effect on SOCS-3 induction in BAEpCs and it is dependent on PI3 kinase signaling pathway. SOCS-3 may represent a potential biomarker for understanding the efficacy and a novel anti-inflammatory mechanism of FP/SAL combination therapy in the treatment of COPD.

Can β2-adrenoceptor agonists, anticholinergic drugs, and theophylline contribute to the control of pulmonary inflammation and emphysema in COPD?

Chronic obstructive pulmonary disease (COPD) has become a global epidemic disease with an increased morbidity and mortality in the world. Inflammatory process progresses and contributes to irreversible airflow limitation. However, there is no available therapy to better control the inflammatory progression and therefore to reduce the exacerbations and mortality. Thus, the development of efficient anti-inflammatory therapies is a priority for patients with COPD. β(2) -Adrenoceptor agonists and anticholinergic agents are widely used as first line drugs in management of COPD because of their efficient bronchodilator properties. At present, many studies in vitro and some data obtained in laboratory animals reveal the potential anti-inflammatory effects of these bronchodilators but their protective role against chronic inflammation and the development of emphysema in patients with COPD remains to be investigated. The anti-inflammatory effects of theophylline at low doses have also been identified. Beneficial interactions between glucocorticoids and bronchodilators have been reported, and signaling pathways explaining these synergistic effects begin to be understood, especially for theophylline. Recent data demonstrating interactions between anticholinergics with β(2) -adrenoceptor agonists aiming to better control the pulmonary inflammation and the development of emphysema in animal models of COPD justify the priority to investigate the interactive effects of a tritherapy associating corticoids with the two main categories of bronchodilators.

Inhaled salmeterol and/or fluticasone alters structure/function in a murine model of allergic airways disease

BACKGROUND

The relationship between airway structural changes (remodeling) and airways hyperresponsiveness (AHR) is unclear. Asthma guidelines suggest treating persistent asthma with inhaled corticosteroids and long acting beta-agonists (LABA). We examined the link between physiological function and structural changes following treatment fluticasone and salmeterol separately or in combination in a mouse model of allergic asthma.

METHODS

BALB/c mice were sensitized to intraperitoneal ovalbumin (OVA) followed by six daily inhalation exposures. Treatments included 9 daily nebulized administrations of fluticasone alone (6 mg/ml), salmeterol (3 mg/ml), or the combination fluticasone and salmeterol. Lung impedance was measured following methacholine inhalation challenge. Airway inflammation, epithelial injury, mucus containing cells, and collagen content were assessed 48 hours after OVA challenge. Lungs were imaged using micro-CT.

RESULTS AND DISCUSSION

Treatment of allergic airways disease with fluticasone alone or in combination with salmeterol reduced AHR to approximately naüve levels while salmeterol alone increased elastance by 39% compared to control. Fluticasone alone and fluticasone in combination with salmeterol both reduced inflammation to near naive levels. Mucin containing cells were also reduced with fluticasone and fluticasone in combination with salmeterol.

CONCLUSIONS

Fluticasone alone and in combination with salmeterol reduces airway inflammation and remodeling, but salmeterol alone worsens AHR: and these functional changes are consistent with the concomitant changes in mucus metaplasia.

COPD exacerbations: defining their cause and prevention

Exacerbations of chronic obstructive pulmonary disease (COPD) are episodes of worsening of symptoms, leading to substantial morbidity and mortality. COPD exacerbations are associated with increased airway and systemic inflammation and physiological changes, especially the development of hyperinflation. They are triggered mainly by respiratory viruses and bacteria, which infect the lower airway and increase airway inflammation. Some patients are particularly susceptible to exacerbations, and show worse health status and faster disease progression than those who have infrequent exacerbations. Several pharmacological interventions are effective for the reduction of exacerbation frequency and severity in COPD such as inhaled steroids, long-acting bronchodilators, and their combinations. Non-pharmacological therapies such as pulmonary rehabilitation, self-management, and home ventilatory support are becoming increasingly important, but still need to be studied in controlled trials. The future of exacerbation prevention is in assessment of optimum combinations of pharmacological and non-pharmacological therapies that will result in improvement of health status, and reduction of hospital admission and mortality associated with COPD.

Is there a role for beta-adrenoceptor agonists in the management of acute lung injury and the acute respiratory distress syndrome?

Despite improvements in general supportive care and ventilatory strategies designed to limit lung injury, no specific pharmacological therapy has yet proven to be efficacious in the management of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Based on experimental studies, as well as studies of the ex-vivo human lung, pulmonary edema fluid clearance from the alveolar space can be augmented by both inhaled and systemic beta2-adrenoceptor agonists (beta2-agonists). Additionally, in the presence of lung injury, beta2-agonists may reduce lung vascular permeability. Treatment with beta2-agonists may also increase the secretion of surfactant and have anti-inflammatory effects. In view of these potentially beneficial effects, beta2-agonist therapy should be evaluated for the treatment of lung injury in humans, particularly because they are already in wide clinical use and do not seem to have serious adverse effects in critically ill patients.

Formoterol attenuates neutrophilic airway inflammation in asthma

STUDY OBJECTIVES

Airway neutrophil levels are increased in patients with severe asthma and during asthma exacerbations. Long-acting beta2-agonists (LABAs), such as formoterol, reduce the number of asthma exacerbations. While beta2-agonists may affect neutrophil function in vitro, it is uncertain whether they have effects on neutrophilic inflammation in asthmatic patients in vivo.

DESIGN

In a double-blind randomized crossover study, we evaluated the effects of 4 weeks of treatment with formoterol (Turbuhaler), 24 microg bid, compared to placebo on sputum neutrophil numbers and interleukin (IL)-8 levels in asthmatic patients. Therapy with budesonide (administered via Turbuhaler), 400 microg bid for 4 weeks, was added at the end as a "gold standard" antiinflammatory effect comparison.

PATIENTS

We studied 15 steroid-naïve nonsmoking patients who ranged from 19 to 51 years of age and had mild persistent asthma.

RESULTS

Formoterol therapy significantly reduced sputum IL-8 levels and neutrophil numbers compared to placebo. There was a significant correlation between the reduction in sputum IL-8 levels and the number of neutrophils, indicating that formoterol may attenuate neutrophilic airway inflammation by inhibiting IL-8 production.

CONCLUSIONS

Our data suggest that the LABA formoterol reduces neutrophilic airway inflammation in patients with mild asthma and that this might be beneficial in preventing asthma exacerbations.

Formoterol added to low-dose budesonide has no additional antiinflammatory effect in asthmatic patients

STUDY OBJECTIVE

Adding inhaled long-acting beta2-agonists to a low dose of inhaled corticosteroids (ICSs) results in better asthma control than increasing the dose of ICSs. An important, but as yet unresolved, question is whether this is due to an additional reduction of airway inflammation.

DESIGN

Double-blind, parallel-group trial.

PATIENTS

Forty asthma patients (FEV1, 50 to 90% predicted; provocative concentration of a substance [methacholine] causing a 20% fall in FEV1 of < 8 mg/mL; no ICSs in the last 4 weeks).

INTERVENTIONS

Randomization to 8 weeks of treatment with 100 microg of budesonide bid plus placebo (BUD200) or 100 microg of budesonide bid plus 12 microg of formoterol (BUD200 + F). Then the dose of budesonide (BUD) was increased to 400 microg bid in both groups for another 8 weeks. Bronchial biopsy specimens were collected before, and after 8 and 16 weeks of treatment. Eosinophils (major basic protein [MBP]) and mast cells (tryptase) were analyzed by immunohistochemistry.

RESULTS

BUD200 reduced the MBP staining (p = 0.008) and tryptase staining (p = 0.048) in the epithelium compared to baseline levels. There were no significant differences between the BUD200 and BUD200 + F groups. In both groups, increasing the dosage of BUD to 800 microg had no significant additional antiinflammatory effect.

CONCLUSIONS

Our results demonstrate that BUD administered at a low dose has significant antiinflammatory effects in patients with mild asthma. No significant additional antiinflammatory effects could be demonstrated either by adding formoterol or by increasing the dose of BUD.

Antiinflammatory effects of salmeterol after inhalation of lipopolysaccharide by healthy volunteers

RATIONALE

Salmeterol is a beta2-adrenoreceptor agonist used in the treatment of obstructive pulmonary disease. Salmeterol inhibits inflammatory responses by neutrophils and mononuclear cells in vitro and in mouse models of lung inflammation in vivo.

OBJECTIVE

To determine the effect of salmeterol on LPS-induced lung inflammation in humans.

METHODS

Thirty-two healthy subjects were enrolled in a single-blinded, placebo-controlled study. Subjects inhaled 100 microg salmeterol or placebo (t=-0.5 h) followed by 100 microg LPS or normal saline (t=0 h; n=8/group). Measurements were performed in bronchoalveolar lavage fluid and purified alveolar macrophages obtained 6 h post-challenge.

MEASUREMENTS AND MAIN RESULTS

Inhalation of LPS was associated with neutrophil influx, neutrophil degranulation (myeloperoxidase, bactericidal/permeability-increasing protein and elastase), release of cytokines (tumor necrosis factor alpha and interleukin 6) and chemokines (interleukin 8, epithelial cell-derived neutrophil attractant 78, macrophage inflammatory proteins 1alpha and 1beta), activation of alveolar macrophages (upregulation of HLA-DR and CD71; enhanced expression of mRNAs for 13 different mediators of inflammation), and protein leakage (all p<0.05 vs. placebo/saline). Pretreatment with salmeterol inhibited LPS-induced neutrophil influx, neutrophil degranulation (myeloperoxidase), tumor necrosis factor alpha release, and HLA-DR expression (all p<0.05 vs. placebo/LPS), while not significantly influencing other responses.

CONCLUSION

Salmeterol exerts antiinflammatory effects in the pulmonary compartment of humans exposed to LPS.

Long-acting beta2-agonists: comparative pharmacology and clinical outcomes

Salmeterol and formoterol are both long-acting beta(2)-adrenoceptor agonists (beta(2)-agonists). They both provide excellent bronchodilating and bronchoprotective effects in patients with asthma but their are some differences between these two long-acting beta(2)-agonists in vitro and in vivo. Formoterol has a greater potency and intrinsic activity than salmeterol, which can become especially apparent at higher doses than that clinically recommended, and in contracted bronchi. Long-term use of long-acting beta(2)-agonists can induce tolerance, which can be partially reversed with corticosteroids. Long-acting beta(2)-agonists have some anti-inflammatory effects in vitro, but data in vivo are less convincing. Compared with doubling the dose of inhaled corticosteroids, the addition of inhaled long-acting beta(2)-agonists to inhaled corticosteroids improves symptom control in patients with asthma and reduces both the exacerbation rate of asthma and hospital admission rate. No enhanced airway responsiveness or loss of perception of dyspnea has been observed with the use of inhaled long-acting beta(2)-agonists. Monotherapy with long-acting beta(2)-agonists is not recommended.

LPS-induced bronchoalveolar neutrophilia; effects of salmeterol treatment

Salmeterol has earlier been reported to have immune modulating effects on Lipopolysaccharide (LPS)-induced neutrophilic inflammation in rodents. The aim of this study was to explore whether 3 weeks regular treatment with inhaled Salmeterol would have a protective effect against neutrophilia, following an LPS inhalation as assessed by bronchoscopy with bronchial wash (BW) and bronchoalveolar lavage (BAL) in healthy subjects. Fifteen volunteers all underwent bronchoscopies with bronchial wash and BAL on three occasions, each being 3 h after inhalation provocation. The initial inhalation was with saline (dilutant) as a reference and the two following with LPS 50 microg diluted in saline. After the saline inhalation the subjects were randomised to treatment with Salmeterol 50 microg twice daily and placebo in a double-blind double-dummy crossover design. Compared to saline inhalation, the LPS inhalations resulted in a two-fold increase in neutrophils both in BW and BAL, respectively (P < or = 0.01). The neutrophilia was present irrespective of the LPS inhalation was preceded by placebo or Salmeterol. This experimental study could not confirm any modulating effect of Salmeterol on LPS-induced airway neutrophilia.

Salmeterol, a beta2-receptor agonist, attenuates lipopolysaccharide-induced lung inflammation in mice

Lipopolysaccharide is ubiquitously present in the environment. To determine the effect of salmeterol, a long-acting beta(2)-receptor agonist, on lipopolysaccharide-induced lung inflammation, mice received lipopolysaccharide (10 microg) intranasally with or without salmeterol intraperitoneally (5 mg/kg) 30 min earlier and 12 h thereafter. Salmeterol dose- and time-dependently inhibited the lipopolysaccharide-induced influx of neutrophils into bronchoalveolar lavage fluid and lung tissue, and these pulmonary neutrophils displayed a reduced expression of CD11b at their surface. To determine the contribution of the salmeterol effect on neutrophil CD11b in the attenuated neutrophil recruitment, we treated mice intranasally exposed to lipopolysaccharide with salmeterol with or without a blocking anti-CD11b antibody. Anti-CD11b profoundly reduced lipopolysaccharide-induced neutrophil influx in bronchoalveolar lavage fluid, an effect that was modestly enhanced by concurrent salmeterol treatment. These data suggest that salmeterol inhibits lipopolysaccharide-induced neutrophil recruitment to the lungs by a mechanism that possibly in part is mediated by an effect on neutrophil CD11b.

Inhaled Salmeterol/Fluticasone Propionate

The salmeterol/fluticasone propionate dry powder inhaler (DPI) [Advair Diskus, Seretide Accuhaler] contains the long-acting beta2-adrenoceptor agonist salmeterol and the inhaled corticosteroid fluticasone propionate. In the US, twice-daily salmeterol/fluticasone propionate 50/250 microg is approved for use in adults with chronic obstructive pulmonary disease (COPD) associated with chronic bronchitis, and in the EU, the twice-daily 50/500 microg dosage is approved for use in patients with severe COPD, repeat exacerbations and significant symptoms despite bronchodilator therapy. In patients with moderate-to-severe COPD, twice-daily inhaled salmeterol/fluticasone propionate 50/250 or 50/500 microg for 24-52 weeks improves predose forced expiratory volume in 1 second (FEV1) significantly more than salmeterol monotherapy, improves postdose or postbronchodilator FEV1 significantly more than fluticasone propionate monotherapy and results in clinically significant improvements in health-related quality of life. Salmeterol/fluticasone propionate 50/500 microg significantly reduced annual COPD exacerbations, especially in severe COPD. Some corticosteroid-related adverse events were increased in recipients of fluticasone propionate with or without salmeterol versus salmeterol monotherapy or placebo; withdrawal from fluticasone propionate, including combination therapy, needs careful management to minimise COPD exacerbations. The DPI combining a corticosteroid and long-acting beta2-agonist provides benefits over monotherapy and may encourage patient compliance in COPD.

Inhaled corticosteroids plus long-acting beta2-agonists as a combined therapy in asthma

Inhaled corticosteroids (ICS) are the mainstay of asthma treatment. Since 1994, when the first trial showed an equivalent effect of doubling the ICS dose or adding salmeterol, it has repeatedly been shown that the combinations of beclomethasone dipropionate and salmeterol, budesonide and formoterol, or fluticasone propionate and salmeterol have at least the same efficacy as doubling the dose of the ICS in adults, though a conclusive trial in asthmatic children is still lacking. The addition of a long-acting beta(2)-agonist (LABA) to ICS appears more efficacious than adding a short-acting beta(2)-agonist or an antileukotriene, even though available data are sparse. Concurrent (two inhalers) and combination (same inhaler) modes of administration are equivalent from the clinical point of view, as is also true regarding administration via metered dose inhaler or dry powder inhaler. Using a single inhaler might eventually have a positive effect on treatment compliance, but there are no confirmatory data yet. Despite some clues regarding a presumed agonist effect of ICS and LABAs, there are still more doubts than certainties. Even though there are still unanswered questions, the data available strongly suggest that the fixed combination of ICS and LABAs using the same inhaler is an efficacious, safe and practical approach for those asthmatic patients who are not well controlled with low doses of ICS alone.

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

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

Comparison of the efficacy, tolerability, and safety of formoterol dry powder and oral, slow-release theophylline in the treatment of COPD

STUDY OBJECTIVE

To compare the efficacy, tolerability, and safety of therapy with formoterol and oral slow-release theophylline (THEO) in patients with COPD.

DESIGN

A randomized, parallel-group study, with double-blind arms for formoterol and placebo (PL) and an open arm for oral slow-release THEO administered in individual doses on the basis of plasma concentrations.

SETTING

Eighty-one centers worldwide.

PATIENTS

Eight hundred fifty-four patients with symptomatic COPD.

INTERVENTION

Comparison of twice-daily inhaled formoterol dry powder (12 or 24 microg), PL, and THEO (individualized doses) over 12 months.

MEASUREMENTS AND RESULTS

Compared to PL, doses of formoterol and THEO both significantly improved the area under the curve for FEV(1) measured over a period of 12 h following the morning dose of study medication at 3 and 12 months (p < 0.001 for all comparisons). Therapy with formoterol, 12 microg, was significantly more effective than that with THEO (p < or = 0.026). Formoterol significantly reduced the percentage of "bad days" (i.e., days with at least two individual symptom scores > or = 2 and/or a reduction in peak expiratory flow from a baseline of > 20%; p < or = 0.035 vs. PL and THEO), and the use of salbutamol rescue medication (p < or = 0.003 vs PL) over the whole treatment period, while the effect of THEO was similar to that of PL. Therapy with formoterol and THEO was more effective than PL at improving quality of life for > 12 months (p < or = 0.030). Treatment-related adverse events and discontinuations were more frequent among patients receiving THEO than among those receiving formoterol.

CONCLUSIONS

Long-term treatment with inhaled formoterol dry powder is more effective and better tolerated than treatment with therapeutically appropriate doses of oral slow-release THEO in symptomatic patients with COPD.

Additive anti-inflammatory effect of formoterol and budesonide on human lung fibroblasts

BACKGROUND

It has been shown that treatment with a long acting beta2 agonist in addition to a glucocorticoid is beneficial in the treatment of asthma. In asthma inflammatory cells, particularly eosinophils, migrate into the pulmonary tissue and airway lumen by means of adhesion molecules expressed on resident tissue cells--that is, fibroblasts--and become activated by cytokines and adhesive interactions. A study was undertaken to determine whether an interaction exists between the long acting beta2 agonist formoterol and the glucocorticoid budesonide on inhibition of adhesion molecule expression, as well as chemo/cytokine production by human lung fibroblasts.

METHODS

Lung fibroblasts were preincubated with therapeutically relevant drug concentrations of 10(-8) M to 10(-10) M. Cells were stimulated with interleukin (IL)-1beta (1 or 10 U/ml) for 8 hours and supernatants were collected for measurement of GM-CSF and IL-8 concentrations. The cells were fixed and subjected to a cell surface ELISA technique to measure the expression of ICAM-1 and VCAM-1.

RESULTS

Formoterol exerted an additive effect on the inhibition of IL-1beta stimulated ICAM-1 and VCAM-1 upregulation and GM-CSF production by budesonide in concentrations of 10(-9) M and above (p<0.05). IL-8 production was not influenced by formoterol.

CONCLUSION

Formoterol exerts an additive effect on the anti-inflammatory properties of budesonide. In vitro data support the finding that the combination of budesonide and formoterol in asthma treatment strengthens the beneficial effect of either drug alone.

Inhaled formoterol dry powder versus ipratropium bromide in chronic obstructive pulmonary disease

We compared the effectiveness of inhaled formoterol with that of ipratropium in the treatment of chronic obstructive pulmonary disease (COPD). After a 2-wk run-in period, 780 patients with COPD were randomized to receive for 12 wk formoterol dry powder 12 or 24 microg twice daily, ipratropium bromide 40 microg four times daily, or placebo in a multicenter, double-blind, parallel-group study. The primary efficacy variable was the area under the curve for forced expiratory volume in 1 s (FEV(1)) measured over 12 h after 12 wk of treatment. Secondary variables included diary symptoms and quality of life. Both doses of formoterol and ipratropium significantly increased the area under the curve for FEV(1) in comparison with placebo (all p < 0.001). Both doses of formoterol were also significantly superior to ipratropium (all p < 0.025). Compared with placebo, both doses of formoterol significantly improved symptoms (all p < or = 0.007) and quality of life (p < 0.01 for total scores) whereas ipratropium did not show significant effects (all p > or = 0.3). All study treatments exhibited a similar safety profile. We conclude that formoterol is more effective than ipratropium bromide in the treatment of COPD, as the efficacy of ipratropium on airflow obstruction does not translate into a clinical benefit that patients can perceive.

Comparison of formoterol and terbutaline for as-needed treatment of asthma: a randomised trial

BACKGROUND

Asthma guidelines recommend that long-acting inhaled beta-agonists should be used as maintenance therapy for patients with asthma inadequately controlled on an inhaled corticosteroid. We studied the safety and efficacy of the long-acting beta-agonist formoterol compared with terbutaline, each taken as needed, in patients with moderate to severe asthma.

METHODS

Patients were taking an inhaled corticosteroid (mean dose 870 microg daily) and had a forced expiratory volume in 1 s (FEV1) of at least 50% predicted (mean 74%). Those requiring an inhaled beta-agonist three to eight times a day during the study run-in period (362 of 621 who started) were randomly assigned formoterol 4.5 microg or terbutaline 0.5 mg as needed by Turbuhaler in daily doses up to 54 microg and 6 mg, respectively, for 12 weeks in a double-blind, parallel-group study. Analyses were by intention to treat.

FINDINGS

The 362 randomised patients (157 men, 205 women) had a mean age of 47 years. Patients taking formoterol had a longer time to their first severe asthma exacerbation (relative-risk ratio 0.55 [95% CI 0.34-0.89]), took fewer inhalations of study drug, and had larger increases in FEV1 (5%) and morning and evening peak expiratory flow (mean difference in increase 11 L/min and 8 L/min) than those taking terbutaline. No safety issues were identified.

INTERPRETATION

When taken as needed, formoterol 4.5 microg provided better asthma control than terbutaline 0.5 mg in patients requiring moderate doses of relief medication despite inhaled corticosteroid treatment. Safety studies should be extended to a wider population of patients with asthma.

Effect of anti-asthmatic drugs on the response to inhaled endotoxin

BACKGROUND

Endotoxin is a pro-inflammatory agent contaminating the dust that has been associated with the risk to develop pulmonary diseases. There is no data on the protective efficacy of anti-asthmatic drugs on the response induced by inhaled endotoxin in human.

METHODS

Twelve mildly asthmatic subjects were submitted weekly to bronchial challenge tests with 20 microg endotoxin. The response was evaluated by the changes in FEV1, blood cells count, neutrophils activation (measured with the luminol-enhanced chemiluminescence) and blood concentration in the acute phase proteins, C-reactive protein (CRP) and haptoglobin. In a double-blind randomized cross-over placebo-controlled design, a single dose each of 500 microg beclomethasone dipropionate, 200 microg salbutamol, and 50 microg salmeterol were administered 30 minutes before the endotoxin challenge test.

RESULTS

The 20-microg endotoxin challenge test induced a significant decrease in FEV1 and luminol-enhanced chemiluminescence (P < .001 and <.05, respectively). There was an increase in the blood neutrophils count (P < .05), in CRP (P < .02) and in haptoglobin (P < .03) concentrations. Pretreatment with beclomethasone dipropionate did not have any significant effect on the response to inhaled endotoxin. Salbutamol and salmeterol completely prevent the FEV1 decline due to their potent bronchodilatation activity. Salmeterol and salbutamol did not have any significant effect on the blood inflammation induced by endotoxin inhalation.

CONCLUSION

The bronchodilating properties of beta2-agonists prevent the lung function response to inhaled endotoxin. When given in a single dose, an inhaled corticosteroid does not have protective activity on the endotoxin-induced blood inflammation.

Effects of salmeterol on host resistance to Trichinella spiralis in rats

Salmeterol is a long-acting beta2-adrenoreceptor agonist. The compound has previously been screened for immunotoxic potential in a repeated dose toxicity study in rats for 28 days. The total serum IgG levels were increased at dose levels of 2 and 10 mg/kg/day. Presently, salmeterol was studied in an immune function assay addressing the host resistance to Trichinella spiralis parasites. Rats were daily treated with salmeterol for 28 days at dose levels of 0, 2, 6 and 10 mg/kg/day. On day 29, the animals were infected with T. spiralis parasites. After six weeks, host resistance was examined. The numbers of T. spiralis muscle larvae in the tongue nor the inflammatory reactions around the encapsulated larvae were affected by salmeterol treatment. The yield of muscle larvae in the whole carcass was not changed either. The IgM, IgA and IgE antibody responses to T. spiralis were unaffected. Only at the highest dose level tested, the anti-T. spiralis IgG antibody response was decreased significantly. However, salmeterol's interference with the generation of anti-T. spiralis antibodies of the IgG subclass apparently did not adversely affect the resistance to infection.

Ligand-independent activation of the glucocorticoid receptor by beta2-adrenergic receptor agonists in primary human lung fibroblasts and vascular smooth muscle cells

The glucocorticoid receptor (GR) is a ubiquitously expressed transcription factor present in most cell types. Upon ligand binding, the GR is activated and translocates into the nucleus where it transmits the anti-inflammatory actions of glucocorticoids. Here, we describe the ligand-independent activation of GR by the beta2-adrenergic receptor (beta2-AR) agonists, salbutamol and salmeterol, in primary human lung fibroblasts and vascular smooth muscle cells. Immunohistochemistry demonstrated expression of GR and the beta2-AR by fibroblasts and vascular smooth muscle cells. Treatment of the cells with the beta2-AR agonists, salbutamol or salmeterol, resulted in translocation of GR into the nucleus beginning at 30 min, as shown by immunohistochemistry and Western blotting of cytosolic and nuclear cell extracts. In comparison, activation of GR induced by the corticosteroids dexamethasone and fluticasone occurred at the same time after treatment (30 min) but resulted in a more complete depletion of GR from the cytosolic compartment. Electrophoretic mobility shift assays confirmed that nuclear GR, activated by both beta2-AR agonists and glucocorticoids, actively bound to the GR consensus sequence (GR element). Functional activation of the GR was confirmed by a Luciferase reporter gene assay, using a GR driven promoter fragment from the p21((WAF1/CIP1)) gene. The effects of the beta2-AR agonists, salbutamol and salmeterol, were dependent upon binding to the beta2-AR, because blocking of beta2-AR with propranolol abrogated GR activation. GR activation appeared to involve cAMP. In summary, these data show that beta2-AR agonists are potent activators of GR. Ligand-independent activation of GR by beta2-AR agonists may substantially mediate the anti-inflammatory actions of these drugs observed in vitro and in vivo.

Effect of Fenoterol on PAF-induced lung edema in isolated and perfused rabbit lungs

We have studied the effects of fenoterol on PAF-induced response in pulmonary circulation. We used 28 isolated and perfused rabbit lungs preparations: eight control preparations (CP), four vehicles preparations (VP), eight PAF preparations (PP) with two doses of PAF, one called low dose (LD = 0.5 microg/kg of weight) and the other high dose (HD = 1 microg/kg of weight) and eight Fenoterol preparations (FP) which we administered 0.05 mg of Fenoterol for 15 min, followed by a LD and HD of PAF. FP prevented elevation of pulmonary artery pressure (Ppa) as compared to PP, at LD of PAF: 12.615 (CI 95%: 8.57-20.885) versus 83.705 (CI 95%: 50.55-114.3) cm of water; and at HD of PAF: 19.38 (CI 95%: 11.235-28.94) versus 205.1 (CI 95%: 141.3-271) cm of water respectively. FP prevented the increase in fluid filtration rate (FFR) observed in PP at both doses of PAF LD: 0.765 (CI 95%: 0.07-3.385) versus 0.01 (CI 95%: -0.05-0.005) g/min; HD: 5.515 (CI 95%: 2.425-8.865) versus 0.03 (CI 95%: 0-0.33) g/min. Our results suggest that PAF has a vasoconstrictor effect that produces lung edema and this effect is inhibited by fenoterol.

Long-acting inhaled beta2-agonists in asthma therapy

OBJECTIVE

To review the pharmacology of the long-acting inhaled beta2-agonists, salmeterol and formoterol, summarize results of their clinical trials, evaluate their safety records, and discuss their roles in the treatment of asthma.

DATA SOURCES

Preclinical and clinical studies involving salmeterol or formoterol were identified by a MEDLINE search, weekly computerized literature updates, and manual searches. Studies of satisfactory quality were chosen for review.

DATA SYNTHESIS

Salmeterol and formoterol are potent and selective beta2-adrenoceptor agonists with durations of action >12 h. Their major differences are that formoterol has a rapid onset of action and is a partial agonist of high intrinsic efficacy, whereas salmeterol has a delayed onset and is a partial agonist of low intrinsic efficacy. Twice daily use of either drug results in improved lung function, reduced symptoms, and a better quality of life. These agents protect against exercise-induced asthma for 12 h and eliminate nighttime awakening in most patients. Limited tolerance develops, especially to their bronchoprotective effects, but their improvement of lung function is sustained.

CONCLUSIONS

Regular use of salmeterol or formoterol provides subjective and objective amelioration of asthma in patients experiencing excessive symptoms or physiologic impairment despite the regular administration of low doses of inhaled corticosteroids (equivalent to approximately 500 microg/d of beclomethasone). Intermittent use of either long-acting beta2-agonist can provide prolonged protection against exercise-induced asthma or nighttime symptoms. Patients should be instructed to continue taking inhaled steroids when long-acting beta2-agonists are administered on a regular schedule and to not take long-acting beta2-agonists between regularly scheduled doses. Used properly, they are effective and safe adjunctive agents in the treatment of asthma.

Effect of inhaled formoterol and budesonide on exacerbations of asthma. Formoterol and Corticosteroids Establishing Therapy (FACET) International Study Group

BACKGROUND

The role of long-acting, inhaled beta2-agonists in treating asthma is uncertain. In a double-blind study, we evaluated the effects of adding inhaled formoterol to both lower and higher doses of the inhaled glucocorticoid budesonide.

METHODS

After a four-week run-in period of treatment with budesonide (800 microg twice daily), 852 patients being treated with glucocorticoids were randomly assigned to one of four treatments given twice daily by means of a dry-powder inhaler (Turbuhaler): 100 microg of budesonide plus placebo, 100 microg of budesonide plus 12 microg of formoterol, 400 microg of budesonide plus placebo, or 400 microg of budesonide plus 12 microg of formoterol. Terbutaline was permitted as needed. Treatment continued for one year; we compared the frequency of exacerbations of asthma, symptoms, and lung function in the four groups. A severe exacerbation was defined by the need for oral glucocorticoids or a decrease in the peak flow to more than 30 percent below the base-line value on two consecutive days.

RESULTS

The rates of severe and mild exacerbations were reduced by 26 percent and 40 percent, respectively, when formoterol was added to the lower dose of budesonide. The higher dose of budesonide alone reduced the rates of severe and mild exacerbations by 49 percent and 37 percent, respectively. Patients treated with formoterol and the higher dose of budesonide had the greatest reductions -- 63 percent and 62 percent, respectively. Symptoms of asthma and lung function improved with both formoterol and the higher dose of budesonide, but the improvements with formoterol were greater.

CONCLUSIONS

In patients who have persistent symptoms of asthma despite treatment with inhaled glucocorticoids, the addition of formoterol to budesonide therapy or the use of a higher dose of budesonide may be beneficial. The addition of formoterol to budesonide therapy improves symptoms and lung function without lessening the control of asthma.

Salmeterol. A review of its pharmacological properties and clinical efficacy in the management of children with asthma

Salmeterol xinafoate is a selective beta 2-adrenoceptor agonist indicated for the maintenance treatment of adults and children with asthma. When administered as a dry powder or aerosol, salmeterol produces bronchodilation for at least 12 hours and protects against methacholine and exercise-induced bronchoconstriction. Salmeterol is not recommended for the treatment of acute exacerbations of asthma. Recent clinical studies have demonstrated the efficacy and tolerability of inhaled salmeterol in the management of asthma in children. Salmeterol improved symptom control and lung function more effectively than placebo or regularly administered salbutamol. In children who were symptomatic despite regular inhaled corticosteroid therapy, the addition of salmeterol to treatment produced a significant improvement in morning and evening peak expiratory flow and forced expiratory volume in 1 second, and a significant reduction in the incidence of asthma exacerbations compared with placebo. Notably, the long duration of action of salmeterol makes it particularly suitable for the prevention of nocturnal asthma symptoms and exercise-induced asthma (EIA) in children. Current data suggest that salmeterol should not be used as a substitute for corticosteroid therapy in children, but rather as an adjunct to therapy. Thus, salmeterol may be a suitable adjunct to therapy in children with asthma receiving inhaled corticosteroids. In addition, salmeterol also has a potentially important role in the prevention of EIA and nocturnal asthma symptoms.

The effect of salmeterol on human eosinophils is both stimulus- and response-dependent

Salmeterol, a long-acting beta 2-adrenoceptor agonist, also possesses some anti-inflammatory properties, but whether eosinophils are the target of such action has been equivocal. To clarify the direct effect of salmeterol on eosinophil functions, we have studied the effect of the drug on the various responses of purified human eosinophils. Superoxide anions (O2-) release and adherence to fibronectin-coated plastic plates induced by platelet-activating factor (PAF), interleukin-5 (IL-5), leukotriene B4 (LTB4) and phorbol myristate acetate (PMA), as well as degranulation induced by C5a and formyl methionyl leucyl phenylalanine (FMLP), in the presence of cytochalasin B (CB) were studied. In the concentration range 10(-8)-10(-5) M, the drug inhibited PAF- and IL-5-induced O2- release, with an IC50 values of 3.2 +/- 1.2 x 10(-7) M and 2.2 +/- 0.4 x 10(-6) M, respectively, Superoxide anion release by LTB4 was only modestly inhibited while that due to PMA was completely unaffected. On the other hand, eosinophil adherence induced by all the 4 stimuli were significantly inhibited within the same concentration range. On eosinophil degranulation, the drug failed to significantly inhibit the release of eosinophil peroxidase (EPO) induced by either C5a or FMLP. In contrast, beta-hexoseaminidase (beta-HA) release by the same agents was significantly inhibited, the inhibition being more pronounced for FMLP-induced, than C5a-induced release. None of the effects of the drug was reversed by the selective beta 2-adrenoceptor antagonist ICI 118551 at a concentration of 10(-7) M. These results show that salmeterol may have some direct inhibitory effects on human eosinophil functions but that these effects are both stimulus- and response-dependent, and are unlikely to be mediated via beta 2 adrenoceptors.

Persistence of effects of nitric oxide synthase inhibitors: comparisons on blood flow and plasma exudation in guinea pig skin

Plasma protein extravasation has been measured in guinea pig skin using 125I-albumin and blood flow using 133Xenon (133Xe) clearance. The nitric oxide (NO) synthase inhibitors N(G)-nitro-L-arginine methyl ester (L-NAME), N(G)-monomethyl-L-arginine (l-NMMA) and N(G)-nitro-L-arginine (L-NOArg) and the alpha-adrenoceptor agonist, phenylephrine, inhibited bradykinin induced plasma protein extravasation when co-injected with the peptide. The inhibitory effects of L-NAME and L-NOArg lasted for up to 8 and 4 h, respectively, whereas phenylephrine and L-NMMA had no persistent inhibitory effects. When co-injected with 133Xe, L-NAME, L-NMMA, L-NOArg and phenylephrine, but not D-NAME, produced significant reductions in skin blood flow. When injected prior to 133Xe, L-NAME and L-NOArg, but not phenylephrine or L-NMMA, significantly reduced flow. The effect of L-NAME on flow was not significant at 8 h. Thus, although the inhibitory effects of the NO synthase inhibitors on mediator induced plasma protein extravasation show correlations with their effects on blood flow, the persistent effect of L-NAME on exudation appears to extend beyond its effect on flow.

Evidence that the eosinophil is a cellular target for the inhibitory action of salmeterol on eosinophil recruitment in vivo

Systemic administration of agents which elevate cyclic AMP (e.g., phosphodiesterase inhibitors, prostanoids, beta-adrenoceptor agonists) effectively modulates eosinophil recruitment in vivo. The present study was undertaken to evaluate whether the eosinophil itself is a cellular target for the inhibitory action of these drugs in vivo. We chose to use the long-acting beta 2-adrenoceptor agonist salmeterol to test this hypothesis. Eosinophils were pretreated with salmeterol (10(-6) M) before washing and testing in two salmeterol-sensitive systems, namely eosinophil aggregation and 111In-eosinophil accumulation in guinea-pig skin. Pretreatment with salmeterol inhibited by 65% and 43% eosinophil aggregation induced by platelet-activating factor (PAF) and human recombinant C5a, respectively. Similarly, 111In-eosinophil accumulation induced by PAF and zymosan-activated plasma, a source of guinea-pig des-Arg-C5a, was inhibited by 55% and 45%, respectively. In contrast, the level of circulating 111In-eosinophils at 1 h was enhanced by 35% in animals which received salmeterol-pretreated 111In-eosinophils. Our results suggest that the eosinophil itself is one of the cellular targets of the inhibitory action of systemically administered salmeterol on eosinophil recruitment in vivo.

Effects of salmeterol and terbutaline on IgE-mediated dermal reactions and inflammatory events in skin chambers in atopic patients

The objective of the present study was to investigate the potential of the long-acting beta 2-agonist salmeterol as an inhibitor of various components of IgE-mediated inflammatory in man. For this purpose, we measured gross skin reactivity (diameters of wheal and flare reaction [WFR] and late cutaneous reaction [LCR] as well as inflammatory cells, mediators, and protein in cutaneous suction blister chambers in eight subjects with allergic rhinitis. Blisters were induced, two on each forearm, by gentle suction and heating, and were unroofed 12 h later, after which plastic chambers were placed over the denuded area. The chambers were challenged for 2 h with antihuman IgE (titer 1:10) in the presence and absence of salmeterol or terbutaline. Normal goat IgG served as negative control. Chamber fluids were removed hourly for the first 4 h, and this followed by a 4-h incubation before final collection. Salmeterol (10(-6)M) and terbutaline (10(-5)M) injected intradermally 30 min before, aw well as together with anti-IgE (titer 1:100), inhibited the WFRs by up to 30%. The effect of salmeterol on the ensuing LCR (75% inhibition at 24 h) tended to be more pronounced than the corresponding inhibition by terbutaline. Both salmeterol and terbutaline very effectively inhibited the anti-IgE-induced extravasation of alpha 2-macroglobulin into skin chambers, with a significantly more sustained effect by salmeterol. Interestingly, only terbutaline reduced the histamine release evoked by anti-IgE. With the present experimental design, where both drugs were washed out from the chambers after 2 h, neither drug inhibited recruitment of leukocytes (including eosinophils). Taken together, salmeterol had a more sustained inhibitory effect than terbutaline on indices of IgE-mediated edema formation (late induration and plasma protein extravasation). On the other hand, under the present experimental conditions, salmeterol failed to reduce the histamine release (in contrast to terbutaline), and neither salmeterol nor terbutaline affected the recruitment of leukocytes.

An immunotoxicity screening study on salmeterol in rats

Salmeterol, a long-acting beta 2-adrenoreceptor agonist without known immunotoxicity, was studied in a 28-day repeated dose toxicity test in Wistar rats. Several immunotoxicity screening parameters were incorporated in the study protocol to investigate the immunotoxic potential of the compound. Male rats were orally treated with 0, 0.2, 2 and 20 mg salmeterol/kg body weight/day. At the 20 mg/kg/day dose level, intubation errors occurred because the animals tried to resist intubation. Some of these animals died intercurrently. Therefore, the magnitude of the dose was lowered to 10 mg/kg/day at day 9 of treatment. Body weight and bone marrow cellularity were not affected. Hematological parameters were not altered either, except for platelet counts, that were decreased at all dose levels. Also liver weights were decreased at all dose levels tested. Absolute thymic weights were decreased at the 2 and 20/10 mg/kg/day dose levels. No treatment-related (histo)pathological lesions were seen in the (non)lymphoid organs. Serum IgM levels were increased at the 0.2, and IgG at the 2 and 20/10 mg/kg/day dose levels, respectively. B cell numbers in the spleen were decreased at all dose levels tested. The data indicate that the test battery applied to salmeterol is able to detect low immunotoxic potential. Further research is needed to elucidate whether salmeterol interferes with immune responses in rats upon antigenic challenge.

Anti-inflammatory, membrane-stabilizing interactions of salmeterol with human neutrophils in vitro

1. We have investigated the effects of salmeterol (0.3-50 microM) on several pro-inflammatory activities of human neutrophils in vitro. 2. Oxidant production by FMLP- and calcium ionophore (A23187)-activated neutrophils was particularly sensitive to inhibition by low concentrations (0.3-3 microM) of salmeterol, while the responses of phorbol myristate acetate- and opsonised zymosan-stimulated cells were affected only by higher concentrations (3-50 microM) of the drug. At these concentrations salmeterol is not cytotoxic, nor does it act as a scavenger of superoxide. 3. These anti-oxidative interactions of salmeterol with neutrophils were insensitive to propranolol but could be eliminated by washing the cells, or by pretreatment with low concentrations (1-2 microM) of the pro-oxidative, membrane-destabilizing phospholipids, lysophosphatidylcholine (LPC), platelet activating factor (PAF) and lysoPAF (LPAF). 4. At concentrations of 6.25-50 microM salmeterol interfered with several other activities of stimulated neutrophils, including intracellular calcium fluxes, phospholipase A2 activity and synthesis of PAF. 5. In an assay of membrane-stabilizing activity, salmeterol (25 and 50 microM) neutralized the haemolytic action of LPC, PAF and LPAF. 6. Of the other commonly used beta 2-adrenoceptor agonists, fenoterol, and formoterol, but not salbutamol, caused moderate inhibition of neutrophil oxidant generation by a superoxide-scavenging mechanism. However, unlike salmeterol, these agents possessed only weak membrane stabilizing properties. 7. We conclude that salmeterol antagonizes the pro-inflammatory, pro-oxidative activity of several bioactive lipids implicated in the pathogenesis of bronchial asthma, by a mechanism related to the membrane-stabilizing, rather than to the beta 2-agonist properties of this agent.

Pharmacological characteristics and species-related variations of beta 3-adrenergic receptors

Beta-adrenergic receptors (beta-AR) belong to the large multigenic family of receptors coupled to GTP-binding proteins. Three subtypes have been identified: beta 1-, beta 2- and beta 3-AR. Much of the work delineating the precise pharmacological comparison of the three beta-ARs has come from investigations with stably transfected Chinese hamster ovary cells (CHO cells). This review discusses the structure and function of beta 3-AR in various species and presents new findings on a number of beta 3-AR ligands including carazolol, tertatolol and CL 316,243 which were found to be selective and potent beta 3-AR agonists and ZD 2079 and salmeterol which appear to display full but non-subtype selective agonistic activity. Species-related variations of the beta 3-AR pharmacology have been shown for propranolol and bupranolol. With the ongoing characterization of the beta 3-AR at the molecular and cellular level, and with the advent of computer-assisted molecular modelling to aid in the determination of the three-dimensional structure of the receptor, it is thought that novel beta 3-AR compounds will become available with improved selectivity and potency.

Inhibition of some aspects of acute inflammation of guinea-pig lung by intraperitoneal dexamethasone and mifepristone: demonstration of agonist activity of mifepristone in the guinea-pig

We have determined the inhibitory activity of dexamethasone as an inhibitor of histamine-induced plasma protein extravasation (PPE) in guinea-pig lung and skin, and of lipopolysaccharide (LPS)-induced neutrophilia and platelet activating factor (PAF)-induced eosinophilia in guinea-pig lungs. Dexamethasone inhibited PAF-induced eosinophilia in guinea-pig lung (ED50 1.4 mg/kg i.p.). Higher doses of dexamethasone were required to inhibit LPS-induced neutrophilia (ED50 10.8 mg/kg i.p.). However, at doses up to 150 mg/kg i.p. dexamethasone did not inhibit histamine-induced plasma protein extravasation (PPE) in guinea-pig lung, but did inhibit PPE in guinea-pig skin. These preparations have previously been shown to be equally sensitive to inhibition by the beta 2-adrenoceptor agonist salmeterol. Dexamethasone inhibited PAF-induced eosinophilia (5 mg/kg) or LPS-induced neutrophilia (50 mg/kg) when given 3 h or 1 h prior to challenge. Inhibitory activity was lost when dexamethasone was administered 23 h prior to LPS or 1 h after PAF. The glucocorticoid antagonist mifepristone (1-100 mg/kg i.p.) caused dose-related inhibition of PAF-induced eosinophilia but not of LPS-induced neutrophilia. The highest dose of mifepristone used (100 mg/kg) did not reverse the inhibitory actions of dexamethasone (50 mg/kg) on LPS-induced neutrophilia. We suggest that the different inhibitory activity of dexamethasone in the preparations studied indicates differences in the sensitivity of the target cells involved to inhibition by dexamethasone. We also suggest that inhibition of PAF-induced eosinophilia by mifepristone reflects the partial agonist activity of this agent, demonstrated by others in different experimental systems.

Anti-inflammatory effects of a short-acting and a long-acting beta 2-adrenoceptor agonist in guinea pig skin

The pharmacological modulation of the accumulation and function of eosinophils in tissues may have a significant impact in the treatment of allergic diseases such as asthma, atopic dermatitis and rhinitis. In this study, we have investigated the acute anti-inflammatory effects of a short-acting (salbutamol) and a long-acting (salmeterol) beta 2-adrenoceptor agonist on 111In-accumulation and oedema formation in allergic and mediator-induced inflammation in guinea pig skin. Both salbutamol and salmeterol inhibited 111In-eosinophil accumulation induced by platelet-activating factor and in a passive cutaneous anaphylactic reaction when co-injected with the inflammatory stimuli or when given as a 30 min pretreatment. The inhibition was reversed by DL-propranolol, but not D-propranolol. Systemic treatment with salbutamol inhibited 111In-eosinophil accumulation and oedema formation when given as a 15 min, but not as a 3 h, pretreatment. In contrast, salmeterol was effective when given at both times. We conclude that a long duration of action of beta 2-adrenoceptor agonists is not necessary to demonstrate acute anti-inflammatory effects on eosinophil accumulation in guinea pig skin.