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

The effects of asthma medications on reactive oxygen species production in human monocytes

OBJECTIVE

Asthma is a chronic inflammatory airway disease induced by many environmental factors. The inhalation of allergens and pollutants promotes the production of reactive oxygen species (ROS) leading to airway inflammation, hyper-responsiveness, and remodeling in allergic asthma. The effects of asthma medications on ROS production are unclear. The present study investigated the anti-ROS effects of current asthma medications including inhaled corticosteroid (ICS; budesonide and fluticasone), leukotriene receptor antagonist (LTRA; montelukast), long-acting β2 agonists (LABAs; salmeterol and formoterol), and a new extra-LABA (indacaterol).

METHODS

The human monocyte cell line THP-1 cells were pre-treated with different concentrations of the asthma medications at different time points after hydrogen peroxide (H₂O₂) stimulation. H₂O₂ production was measured with DCFH-DA by flow cytometry.

RESULTS

Montelukast, fluticasone, and salmeterol suppressed H₂O₂-induced ROS production. Indacaterol enhanced H₂O₂-induced ROS production. Budesonide and formoterol alone had no anti-ROS effects, but the combination of these two drugs significantly suppressed H₂O₂-induced ROS production.

CONCLUSIONS

Different asthma medications have different anti-ROS effects on monocytes. The combination therapy with LABA and ICS seemed not to be the only choice for asthma control. Montelukast may also be a good supplemental treatment for the poorly controlled asthma because of its powerful anti-ROS effects. Our findings provide a novel therapeutic view in asthma.

Formoterol

Inhaled formoterol is a long-acting selective beta2-adrenoceptor agonist, with an onset of action of 5 minutes postdose and a bronchodilator effect that lasts for at least 12 hours. Statistically significant and clinically relevant (>120 ml) improvements in lung function [assessed using standardized/normalized area under the forced expiratory volume in 1 second (FEV1) versus time curve (AUC FEV1)] were observed with inhaled formoterol 12 microg twice daily (the approved dosage in the US) compared with placebo in 12-week and 12-month, randomized, double-blind trials in patients with chronic obstructive pulmonary disease (COPD). The bronchodilator efficacy of formoterol 12 microg twice daily was greater than that of oral slow-release theophylline (individualized dosages) in a 12-month trial or inhaled ipratropium bromide 40 microg four times daily in a 12-week trial. Improvement in AUC FEV1 with formoterol, but not theophylline, compared with placebo was observed in patients with irreversible or poorly-reversible airflow obstruction. Formoterol also significantly improved health-related quality of life compared with ipratropium bromide or placebo and significantly reduced symptoms compared with placebo. Combination therapy with formoterol 12 microg twice daily plus ipratropium bromide 40 microg four times daily was significantly more effective than albuterol (salbutamol) 200 microg four times daily plus the same dosage of ipratropium bromide in a 3-week, randomized, double-blind, double-dummy, crossover trial. Inhaled formoterol was well tolerated in clinical trials. The incidence of investigator-determined drug-related adverse events with inhaled formoterol 12 microg twice daily was similar to that with placebo and inhaled ipratropium bromide 40 microg four times daily but lower than that with oral slow-release theophylline (individualized dosages). Importantly, there were no significant differences between formoterol and placebo or comparator drugs in cardiovascular adverse events in patients with COPD and corrected QT interval values within the normal range. In conclusion, inhaled formoterol improved lung function and health-related quality of life and reduced symptoms relative to placebo in clinical trials in patients with COPD. The drug had greater bronchodilator efficacy than oral slow-release theophylline or inhaled ipratropium bromide and showed efficacy in combination with ipratropium bromide. The adverse events profile (including cardiovascular adverse events) with formoterol was similar to that with placebo. Thus, inhaled formoterol may be considered as a first-line option for the management of bronchoconstriction in patients with COPD who require regular bronchodilator therapy for the management of symptoms.

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.

Agonist- and hydrogen peroxide-mediated oxidation of the β2 adrenergic receptor: evidence of receptor s-sulfenation as detected by a modified biotin-switch assay

Reactive oxygen species (ROS), including hydrogen peroxide (H(2)O(2)), have recently been shown to be generated upon agonism of several members of the G protein-coupled receptor (GPCR) superfamily, including β(2)-adrenergic receptors (β(2)ARs). Previously, we have demonstrated that inhibition of intracellular ROS generation mitigates β(2)AR signaling, suggesting that β(2)AR-mediated ROS generation is capable of feeding back to regulate receptor function. Given that ROS, specifically H(2)O(2), are able to post-translationally oxidize protein cysteine sulfhydryls to cysteine-sulfenic acids, the goal of the current study was to assess whether ROS are capable of S-sulfenating β(2)AR. Using a modified biotin-switch assay that is selective for cysteine-sulfenic acids, our results demonstrate for the first time that H(2)O(2) treatment facilitates S-sulfenation of transiently overexpressed β(2)AR in human embryonic kidney 293 cells. It is noteworthy that stimulation of cells with the β-agonist isoproterenol produces both dose- and time-dependent S-sulfenation of β(2)AR, an effect that is receptor-dependent, and demonstrates that receptor-generated ROS are also capable of oxidizing the β(2)AR. Receptor-dependent S-sulfenation was inhibited by the chemoselective sulfenic acid alkylator dimedone and the cysteine antioxidant N-acetyl-l-cysteine. Moreover, our results reveal that receptor oxidation occurs in cells that endogenously express physiologically relevant levels of β(2)AR, because treatment of human alveolar epithelial A549 cells with either H(2)O(2) or the β(2)-selective agonist formoterol promoted receptor S-sulfenation. These findings provide the first evidence, to our knowledge, that a mammalian GPCR can be oxidized by S-sulfenation and signify an important first step toward shedding light on the overlooked role of ROS in the regulation of β(2)AR function.

Short courses of antibiotics for children and adults with bronchiectasis

BACKGROUND

Bronchiectasis is an important cause of respiratory morbidity in both developing and developed countries. Antibiotics are considered standard therapy in the treatment of this condition but it is unknown whether short courses (four weeks or less) are efficacious.

OBJECTIVES

To determine whether short courses of antibiotics (i.e. less than or equal to four weeks) for treatment of acute and stable state bronchiectasis, in adults and children, are efficacious when compared to placebo or usual care.

SEARCH STRATEGY

The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE, OLDMEDLINE, CINAHL, AMED and PsycINFO and handsearching of respiratory journals and meeting abstracts were performed by the Cochrane Airways Group up to February 2011.

SELECTION CRITERIA

Only randomised controlled trials were considered. Adults and children with bronchiectasis (defined clinically or radiologically) were included. Patients with cystic fibrosis were excluded.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed the titles, abstracts and citations to assess eligibility for inclusion. Only one study fulfilled the inclusion criteria and thus meta-analysis could not be performed.

MAIN RESULTS

The single eligible study showed a small benefit, when compared to placebo, of four weeks of inhaled antibiotic therapy in adults with bronchiectasis and pseudomonas in their sputum. There were no studies in children and no studies on oral or intravenous antibiotics.

AUTHORS' CONCLUSIONS

There is insufficient evidence in the current literature to make reasonable conclusions about the efficacy of short course antibiotics in the management of adults and children with bronchiectasis. Until further evidence is available, adherence to current treatment guidelines is recommended.

Effect of procaterol on Th2-related chemokines production in human monocyte and bronchial epithelial cells

Procaterol is a β2-adrenoceptor agonist used as a bronchodilator for the treatment of asthma; it also possesses an anti-inflammatory property. As chemokines play a pivotal role in inflammation and the pathogenesis of asthma, we investigated the effects of procaterol on type 2 helper T cell (Th2)-related [macrophage-derived chemokine (MDC) and I-309] and type 1 helper T cell (Th1)-related chemokines [monokine-induced by IFN-gamma (Mig) and interferon-inducible protein 10 (IP-10)] production of THP-1 cells and human primary monocytes. The effect on thymus- and activation-regulated chemokine (TARC) production in BEAS-2B cells was also evaluated. Nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) inhibitors were used to ascertain the intracellular signal pathways involved, and etazolate, a phosphodiesterase 4 inhibitor, was used to assess the correlation between the β2-adrenoceptor-cAMP pathway and the effect on chemokines. In addition, chromatin immunoprecipitation assays (ChIPs) were performed to detect histone modification in the TARC promoter region. MDC and I-309 production of both THP-1 cells and primary human monocytes, as well as TARC expression of BEAS-2B cells, were significantly inhibited by procaterol (10(-10)-10(-7) M); however, procaterol did not suppress Mig and IP-10 expression by THP-1 cells. MDC secreted by monocytes is associated with the NF-κB and MAPK signaling pathways, in particular p38- and c-Jun N-terminal kinase (JNK) MAPKs. Etazolate blocked the expression of MDC by THP-1 cells and TARC by BEAS-2B cells. ChIP assay revealed decreased trimethylation of lysine 4 in histone 3 (H3K4) in the TARC promoter region of BEAS-2B cells. In conclusion, procaterol could inhibit Th2-related chemokines production in human monocytes and bronchial epithelial cells, an effect that may be mediated through not only the NF-κB, p38, and JNK-MAPK pathways, but also the β2-adrenoceptor-cAMP pathway. Most importantly, the suppressive effect of Th2-related chemokines production by procaterol might be regulated via post-transcriptional modification by decreasing H3K4 trimethylation.

Formoterol in the management of chronic obstructive pulmonary disease

Bronchodilators represent the hallmark of symptomatic treatment of Chronic Obstructive Pulmonary Disease (COPD). There are four categories of bronchodilators: anticholinergics, methylxanthines, short-acting β₂-agonists, and long-acting β₂-agonists such as formoterol. Significant research has been performed to investigate the efficacy, safety and tolerability of formoterol in the therapeutic field of COPD. Formoterol exhibits a rapid onset of bronchodilation similar to that observed with salbutamol, yet its long bronchodilatory duration is comparable to salmeterol. In addition, formoterol presents with a clear superiority in lung function improvement compared with either ipratropium bromide or oral theophylline, while its efficacy improves when administered in combination with ipratropium. Formoterol has been shown to better reduce dynamic hyperinflation, which is responsible for exercise intolerance and dyspnea in COPD patients, compared with other bronchodilators, whereas it exerts synergistic effect with tiotropium. Moreover, formoterol reduces exacerbations, increases days free of use of rescue medication and improves patients’ quality of life and disease symptoms. Formoterol has a favorable safety profile and is better tolerated than theophylline. Collectively, data extracted from multicenter clinical trials support formoterol as a valid therapeutic option in the treatment of COPD.

Cells, mediators and Toll-like receptors in COPD

Chronic obstructive pulmonary disease (COPD) is a global health problem. Being a progressive disease characterized by inflammation, it deteriorates pulmonary functioning. Research has focused on airway inflammation, oxidative stress, and remodelling of the airways. Macrophages, neutrophils and T cells are thought to be important key players. A number of new research topics received special attention in the last years. The combined use of inhaled corticosteroids and long-acting beta(2)-adrenoceptor agonists produces better control of symptoms and lung function than that of the use of either compound alone. Furthermore, collagen breakdown products might be involved in the recruitment and activation of inflammatory cells by which the process of airway remodelling becomes self-sustaining. Also, TLR (Toll-like receptor)-based signalling pathways seem to be involved in the pathogenesis of COPD. These new findings may lead to new therapeutic strategies to stop the process of inflammation and self-destruction in the airways of COPD patients.

Improved outcomes in patients with chronic obstructive pulmonary disease treated with salmeterol compared with placebo/usual therapy: results of a meta-analysis

Background

Several studies have demonstrated that long-acting β₂-agonists such as salmeterol are beneficial in chronic obstructive pulmonary disease (COPD). A meta-analysis was therefore conducted to review studies in COPD to provide pooled estimates of the effect of salmeterol 50 mcg taken twice daily in addition to usual therapy on several clinically relevant endpoints, when compared with placebo/usual therapy.

Methods

An extensive search of literature and clinical trial databases was conducted using the terms salmeterol, COPD, chronic, obstructive, bronchitis and emphysema. Nine randomized, double-blind, parallel-group, placebo-controlled trials of ≥12 week duration with salmeterol 50 mcg bid treatment in COPD were included (>3500 patients), with a further 14 trials excluded due to study design or reporting timelines. All patients were included, and a sub-group of subjects (84%) with poorly reversible COPD were considered separately. Statistical testing was carried out at the 5% level, except for interaction testing which was carried out at the 10% level.

Results

Patients treated with salmeterol over 12 months were less likely to withdraw early from the studies (19% patients compared with 25% on their current usual therapy, p < 0.001), less likely to suffer a moderate/severe exacerbation (34% compared with 39%, p < 0.0001) and had a greater increase in average FEV₁ (73 mL difference vs placebo/usual therapy, p < 0.0001). Similar differences were found at 3 and 6 months. At all time points, more patients experienced an improvement in health status and also a greater change with salmeterol than with placebo/usual therapy (p < 0.002). There was no evidence of tachyphylaxis to salmeterol over 12 months.

Conclusion

The meta-analysis confirmed clinically and statistically significant, sustained and consistent superiority of salmeterol 50 mcg bid over placebo/usual therapy on a broad range of outcome measures.

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.

New treatment regimes for virus-induced exacerbations of asthma

This review will focus on the role of viruses as causes of asthma exacerbations. The article will briefly review the current literature supporting this view, with a special focus on human rhinovirus (RV), the main virus associated with exacerbations of asthma. The review will then refer to possible strategies for treatment, and will include discussion on treatment with specific anti-viral therapy and type I interferon as a treatment for RV. The review will also include a discussion on current therapies for asthma, such as glucocorticosteroid and beta(2) agonist therapy alone and in combination and why this may be relevant to virus-induced exacerbations of asthma. Finally, the potential for future anti-inflammatory/immunomodulatory therapies with a focus on NF-kappaB inhibition will be discussed.

Long-acting beta2-adrenergic formoterol and salmeterol induce the apoptosis of B-chronic lymphocytic leukaemia cells

B-cell chronic lymphocytic leukaemia (B-CLL) is a neoplastic disorder characterized by defective apoptosis, cell accumulation in G0/G1, and high expression of BCL2 oncogene. Intracellular cyclic adenosine monophosphate (cAMP) accumulation increases the chemosensitivity of B-CLL cells in vitro and in vivo. In the present study, we investigated the effects of beta2-adrenergic compounds, well known cAMP-inducing drugs, on the in vitro survival of leukaemia cells. In contrast to the short-acting beta2-mimetic (beta2Mim) salbutamol, a consistent pro-apoptotic effect was observed with the long-acting beta2Mim salmeterol and formoterol. Normal B cells isolated from control donors were totally resistant to the above molecules. These compounds also increased chlorambucil- and fludarabine-induced death of B-CLL cells. Blockade of beta-adrenergic receptor signalling or cAMP did not alter B-CLL apoptosis with beta2 Mimagents. Leukaemia cell apoptosis by beta2Mim correlated with an increase in calcium influx, decreased bcl-2 protein and mRNA levels, increase in BAX gene expression and a marked rise in BCL2/BAX mRNA ratios. Interleukin-4, a cytokine that increases bcl-2 expression in B-CLL cells, rescued leukaemia cell from apoptosis with beta2Mim. These data show that long-acting beta2-adrenergic agents promote apoptotic leukaemia cell death through an adrenoreceptor- and cAMP-independent, Ca2+-dependent mechanism.

Zeta-potential measurements as a tool to quantify the effect of charged drugs on the surface potential of egg phosphatidylcholine liposomes

The binding of charged drugs to neutral phosphatidylcholine membranes was assessed by measuring their zeta-potential values in the presence of different drug concentrations. This methodology was applied to the study of the concentration effects of two nonsteroidal antiinflammatory drugs (NSAIDs). Results revealed an intense membrane charging that was proportional to the amount of negatively charged drug in the media. A mathematical formalism was adapted and an analytical expression derived to calculate directly surface potentials from zeta-potential data. The membrane loading state, expressed as the number of molecules per unit area, was calculated for the negative and for the neutral forms of the drugs. An approach was also developed that allows the determination of the maximum number of molecules per unit area by fitting a binding isotherm to the dependence of the number molecules per unit area with the drug concentration. The calculation of the maximum mol lipid/drug ratio can also be estimated and related to the binding stoichiometry, as well as to the maximum lipid loading capacity. Furthermore, the concentration profiles for both drugs can be established in terms of the distance to the liposome surface. The developed methodology allowed for the simultaneous determination of partition coefficients (Kp) for the NSAIDs in lipid/aqueous media because zeta-potential values can be related to the drug concentration at the lipid/ aqueous media interface. Alternative independent methodologies were used to determine Kp: spectrophotometric and centrifugation assays. A mathematical relation was developed to compare the Kp values determined from the zeta-potential data with those obtained from the other techniques used because in the former case they are calculated on the basis of the number of molecules per unit area and in the latter on the basis of the total drug concentrations in solution, and the values of the partition coefficients obtained from all the techniques were found to be equal, within the experimental error. This methodology constitutes a more straightforward method than the other techniques used because partition coefficients for all drug forms (charged and noncharged) can be assessed with a minimum number of experimental determinations and it allows for a characterization of the electrostatic properties of neutral membranes upon binding of charged drugs.

The efficacy and safety of fluticasone propionate (250 microg)/salmeterol (50 microg) combined in the Diskus inhaler for the treatment of COPD

STUDY OBJECTIVES

To compare the efficacy and safety of the inhaled corticosteroid fluticasone propionate (FP) and the inhaled long-acting beta(2)-agonist salmeterol (SM), when administered together in a single device (Diskus; GlaxoSmithKline, Inc; Research Triangle Park, NC), with that of placebo and the individual agents alone in patients with COPD.

DESIGN

Randomized, double-blind, multicenter, placebo-controlled study.

SETTING

Seventy-six investigative sites in the United States.

PATIENTS

Seven hundred twenty-three patients > or =40 years of age with COPD and a mean baseline FEV(1) of 42% predicted.

INTERVENTIONS

FP (250 microg), SM (50 microg), FP plus SM combined in a single inhaler (FSC), or placebo administered twice daily through the Diskus device for 24 weeks.

MEASUREMENTS

Primary efficacy measures were morning predose (ie, trough FEV(1)) for FSC compared with SM and 2-h postdose FEV(1) for FSC compared with FP. Other efficacy measures were as follows: morning peak expiratory flow rate (PEF); transition dyspnea index; chronic respiratory disease questionnaire; chronic bronchitis symptom questionnaire; exacerbations; and other symptomatic measures.

RESULTS

At Endpoint (ie, the last on-treatment, post-baseline assessment), treatment with FSC significantly (p < or = 0.012) increased the morning predose FEV(1) (165 mL) compared with SM (91 mL) and placebo (1 mL), and significantly (p < or = 0.001) increased the 2-h postdose FEV(1) (281 mL) compared with FP (147 mL) and placebo (58 mL). Improvements in lung function with FSC compared with FP and SM, and with FP and SM compared with placebo, as measured by the average daily morning PEF, was observed within approximately 24 h after the initiation of treatment, indicating an early onset of effect (p < or = 0.034). Compared with placebo, FSC significantly improved dyspnea, quality of life, and symptoms of chronic bronchitis. The incidence of adverse effects (except for an increase in oral candidiasis with FSC and FP) were similar among the treatment groups.

CONCLUSIONS

Treatment with FSC (FP, 250 microg, and SM, 50 microg) twice daily substantially improved morning lung function and sustained these improvements for over a period of 24 weeks compared with FP or SM treatment alone in patients with COPD, with no additional safety concerns for the combination treatment vs that with the individual components.

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.

Inhibition by fenoterol of human eosinophil functions including beta2-adrenoceptor-independent actions

Agonists at beta2 adrenoceptors are used widely as bronchodilators in treating bronchial asthma. These agents also may have important anti-inflammatory effects on eosinophils in asthma. We examined whether widely prescribed beta2-adrenoceptor agonists differ in ability to suppress stimulus-induced eosinophil effector functions such as superoxide anion (O2-) generation and degranulation. To examine involvement of cellular adhesion in such responses, we also investigated effects of beta2 agonists on cellular adhesion and on CD11b expression by human eosinophils. O2- was measured using chemiluminescence. Eosinophil degranulation and adhesion were assessed by a radioimmunoassay for eosinophil protein X (EPX). CD11b expression was measured by flow cytometry. Fenoterol inhibited platelet-activating factor (PAF)-induced O2- generation by eosinophils significantly more than salbutamol or procaterol. Fenoterol partially inhibited PAF-induced degranulation by eosinophils similarly to salbutamol or procaterol. Fenoterol inhibited phorbol myristate acetate (PMA)-induced O2- generation and degranulation by eosinophils, while salbutamol or procaterol did not. Fenoterol inhibition of PMA-induced O2- generation was not reversed by ICI-118551, a selective beta2-adrenoceptor antagonist. Fenoterol, but not salbutamol or procaterol, significantly inhibited PAF-induced eosinophil adhesion. Fenoterol inhibited O2- generation and degranulation more effectively than salbutamol or procaterol; these effects may include a component involving cellular adhesion. Inhibition also might include a component not mediated via beta2 adrenoceptors.

Evaluation of different inhaled combination therapies (EDICT): a randomised, double-blind comparison of Seretide (50/250 microg bd Diskus vs. formoterol (12 microg bd) and budesonide (800 microg bd) given concurrently (both via Turbuhaler) in patients with moderate-to-severe asthma

The aim of this study was to compare the efficacy safety and cost of Seretide (salmeterol/fluticasone propionate (Salm/FP), 50/250 microg bd) via Diskus with formoterol (Form; 12 microg bd) and budesonide (Bud; 800 microg bd) given concurrently (Form+Bud) via Turbuhaler in patients with moderate-to-severe asthma who were uncontrolled on existing corticosteroid therapy. The study used a randomised, double-blind, double-dummy, parallel-group design, consisting of a 2-week run-in period on current corticosteroid therapy (1000-1600 microg/day of BDP or equivalent) and a 12-week treatment period. Symptomatic patients (n = 428) with FEV1 of 50-85% predicted and increased symptom scores or reliever use during run-in were randomly allocated to receive either Salm/FP (50/250 microg bd) via a single Diskus inhaleror Form+Bud (12+800 microg bd) via separate Turbuhalers. Clinic, diary card and asthma-related health-care resource utilisation data were collected. Improvement in mean morning peak expiratory flow (PEFam was similar in the Salm/FP and Form+Bud groups. Both PEFam and mean evening PEF (PEFpm) increased by a clinically significant amount (>20 L/min) from baseline in both treatment groups. The mean rate of exacerbations (mild, moderate or severe) was significantly lower in the Salm/FP group (0.472) compared with the Form+Bud group (0.735) (ratio = 0.64; P < 0.001), despite the three-fold lower microgram inhaled corticosteroid dose in the Salm/FP group. Patients in the Salm/FP group also experienced significantly fewer nocturnal symptoms, with a higher median percentage of symptom-free nights (P = 0.04), nights with a symptom score <2 (P = 0.03), and nights with no awakenings (P = 0.02). Total asthma-related health-care costs were significantly lower in the Salm/FP group than the Form+Bud group (P<0.05). Both treatments were well tolerated, with a similar low incidence of adverse events. This study showed that in symptomatic patients with moderate-to-severe asthma, Salm/FP (50/250 microg bd), administered in a single convenient device (Diskus), was at least as effective as an approximately three-fold higher microgram corticosteroid dose of Bud (800 microg bd) given concurrently with Form (12 microg bd) in terms of improvement in PEFam, and superior at reducing exacerbations and nights with symptoms or night-time awakenings. Salm/FP was also the less costly treatment due primarily to lower hospitalisation and drug costs.

Beta-agonists

Beta-Agonists are a mainstay of asthma treatment. Short-acting beta-agonists are the most effective bronchodilators for rescue or quick relief of symptoms. Long-acting beta-agonists have a key role in long-term control when added to inhaled corticosteroid therapy, and are especially useful in the control of nocturnal asthma. Both types of beta-agonists may be used in the prophylaxis of exercise-induced asthma with long-acting beta-agonists providing more prolonged protection. beta-Agonists have minimal side effects and are safe when used appropriately.

Fenoterol inhibits superoxide anion generation by human polymorphonuclear leukocytes via beta-adrenoceptor-dependent and -independent mechanisms

BACKGROUND

Beta2-adrenoceptor agonists, used widely as bronchodilator in treating bronchial asthma, may have anti-inflammatory activity.

OBJECTIVE

We examined whether various widely prescribed beta2-adrenoceptor agonists differ in anti-inflammatory mechanisms.

METHODS

We investigated effects of these drugs on superoxide anion generation by stimulated human polymorphonuclear leukocytes in vitro using chemiluminescence.

RESULTS

At high concentrations, fenoterol significantly inhibited both N-formylmethionyl-leucyl-phenylalanine- and phorbol myristate acetate-induced superoxide generation by neutrophils. In contrast, salbutamol or procaterol partially inhibited generation with the former stimulus but not the latter. Inhibition by salbutamol or procaterol was completely reversed by either propranolol, a nonselective beta-adrenoceptor antagonist, or ICI-118551, a beta2-adrenoceptor-selective antagonist. In contrast, the effect of fenoterol at concentrations exceeding 10(-6) M against superoxide generation with the former stimulus was only partially reversed by antagonists, and the effect of high concentrations of fenoterol against generation with the latter stimulus was not reversed. No drugs scavenged superoxide at the highest concentration used (10(-5) M).

CONCLUSIONS

Fenoterol at high concentrations has an inhibitory effect on superoxide generation that includes a component not mediated via beta2-adrenoceptors. Direct inhibition at or downstream from protein kinase C may be involved.

Platelet-activating factor and lyso-PAF possess direct antimicrobial properties in vitro

The effects of platelet-activating factor (PAF) and lyso-platelet-activating factor (L-PAF) at concentrations of 0.25-20 microg/ml on potassium transport and growth of gram-positive and gram-negative bacteria have been investigated in vitro and compared with those of lysophosphatidylcholine (LPC). Potassium transport was determined using 86Rb+ as tracer, while growth was measured according to the extent of uptake of radiolabeled amino acids. All of the test phospholipids caused dose-related inhibition of 86Rb+-uptake and growth of gram-positive bacteria, the order of potency being PAF>LPC>L-PAF. Gram-negative bacteria, on the other hand, were less sensitive to the inhibitory effects of the phospholipids on K+ transport and growth. Some, but not all, of the gram-positive and gram-negative bacteria were able to degrade LPC, but not PAF or L-PAF, demonstrating that enzymatic degradation of phospholipids does not explain the differential sensitivity to these agents. The bioactive phospholipids LPC, PAF and L-PAF may represent an oxygen-independent antimicrobial host defense system operative primarily against gram-positive bacteria.

Vitamin E attenuates the injurious effects of bioactive phospholipids on human ciliated epithelium in vitro

Bioactive phospholipids (PL), particularly lysophosphatidylcholine (LPC), are being increasingly implicated in the pathogenesis of various acute and chronic inflammatory disorders, particularly those of the airways, while there is emerging evidence that vitamin E may function as a natural antagonist of these lipid mediators of inflammation. The aims of this study were to document the effects of vitamin E on the inhibition of ciliary beating and damage to structural integrity of human ciliated epithelium induced by the PL, platelet-activating factor (PAF), lyso-PAF and LPC in vitro in relation to the anti-oxidative and membrane-stabilizing properties of the vitamin. Ciliary beat frequency was measured by a phototransistor technique, and damage to structural integrity assessed by a visual-scoring index, while superoxide production by polymorphonuclear leukocytes and membrane-stabilizing potential were measured using lucigenin-enhanced chemiluminescence and haemolytic procedures, respectively. All three PL caused inhibition of ciliary beating and structural damage to human ciliated epithelium by membrane-directed cytotoxic mechanisms, which were potentiated by human polymorphonuclear leukocytes due to induction of oxidant-mediated injury. Both direct and phagocyte-inflicted epithelial injury was attenuated by vitamin E. In haemolytic and chemiluminescence assays, vitamin E neutralized both the membrane-destabilizing and pro-oxidative actions of all three PL, while spectrophotometric analysis of mixtures of vitamin E with PAF, lyso-PAF and LPC revealed alterations in peak intensity, as well as peak shifts, indicative of physicochemical interactions between the vitamin and the PL. Vitamin E status may be a determinant of susceptibility to phospholipid-mediated airway inflammation and damage.

Alternative mechanisms for long-acting beta(2)-adrenergic agonists in COPD

beta(2)-Adrenergic agonists are commonly used as bronchodilators to treat patients with COPD. In addition to prolonged bronchodilation, long-acting beta(2)-agonists (LABAs) exert other effects that may be of clinical relevance. These include inhibition of airway smooth-muscle cell proliferation and inflammatory mediator release, as well as nonsmooth-muscle effects, such as stimulation of mucociliary transport, cytoprotection of the respiratory mucosa, and attenuation of neutrophil recruitment and activation. This review details the possible alternative mechanisms of action of the LABAs, salmeterol and formoterol, in COPD.

Salmeterol plus theophylline combination therapy in the treatment of COPD

BACKGROUND

Patients with COPD often require multiple therapies to improve lung function and decrease symptoms and exacerbations. Salmeterol and theophylline are indicated for the treatment of COPD, but the use of these agents in combination has not been extensively studied.

OBJECTIVES

To compare the efficacy and safety of salmeterol plus theophylline vs either agent alone in COPD.

METHODS

Randomized, double-blind, double-dummy, parallel-group trial in 943 patients with COPD. After an open-label theophylline titration period (serum levels, 10 to 20 microg/mL), patients were randomly assigned to receive salmeterol (42 microg bid) plus theophylline, salmeterol (42 microg bid), or theophylline for 12 weeks. Serial pulmonary function tests were completed on day 1 and treatment week 12. Patients kept diary cards and noted their peak flow rates, symptom scores, and albuterol use, and periodically completed quality-of-life and dyspnea questionnaires.

RESULTS

All three groups significantly improved compared with baseline. Combination treatment with salmeterol plus theophylline provided significantly (p < or = 0.045) greater improvements in pulmonary function; significantly (p < or = 0.048) greater decreases in symptoms, dyspnea, and albuterol use; and significantly fewer COPD exacerbations (p = 0.023 vs theophylline). In general, treatment with salmeterol provided greater improvement in lung function and satisfaction with treatment compared with theophylline. Salmeterol treatment was also associated with significantly fewer drug-related adverse events (p < or = 0.042) than either treatment that included theophylline. The safety profile (adverse events, vital signs, and ECG findings) of the two treatments that included theophylline were similar.

CONCLUSION

Patients with COPD may benefit from combination treatment with salmeterol plus theophylline, without a resulting increase in adverse events or other adverse sequelae.

The effect of salmeterol on markers of airway inflammation following segmental allergen challenge

Inflammation is a critical component of asthma. Drugs that control asthma generally reduce the degree of airway inflammation. There is theoretical controversy surrounding the effects of beta(2)-agonists on airway inflammation, with some studies suggesting an anti-inflammatory effect, and others predicting a proinflammatory influence. We conducted a double-blind, placebo-controlled, crossover study of the effect of the long-acting beta(2)-agonist salmeterol on airway inflammation induced by segmental allergen challenge (SAC). We studied 13 allergic asthmatics controlled with as needed inhaled short-acting beta(2)-agonists alone, and used bronchoalveolar lavage 5 min and 48 h after SAC to assess airway inflammation, and the effects of salmeterol on this process. Salmeterol therapy improved FEV(1), but had no significant effect on the immediate or late cellular response to SAC. One measure of superoxide production was reduced, and interleukin-4 (IL-4) was reduced in baseline samples, but other indices of airway inflammation were unchanged by salmeterol therapy. We conclude that salmeterol therapy alone does not meaningfully reduce airway inflammation induced by SAC, but equally importantly, does not result in amplified inflammation.

Ca(2+)-dependent production of reactive oxygen metabolites by human neutrophils in response to fluorinated propranolol analogues

Fluorinated analogues of propranolol, namely trifluoroethyl propranolol (F3), pentafluoropropyl propranolol (F5), and heptafluorobutyl propranolol (F7), were found to induce reactive oxygen metabolite (ROM) production in human neutrophils in a dose-dependent manner. Preincubation of neutrophils with the calcium chelator BAPTA-AM or the tyrosine kinase inhibitor genistein inhibited this ROM production. Direct measurements of intracellular calcium revealed that these analogues caused a transient increase in intracellular calcium. In addition, these fluorinated analogues of propranolol caused a transient increase in actin polymerization. The effects of these compounds were found to be dependent upon the degree of fluorination of the parent compound. Propranolol, on the other hand, had no direct effect on ROM, calcium, or actin polymerization when added alone to neutrophils, although it did modify responses of cells to various stimuli. Whereas ROM production induced by the chemotactic peptide formyl-methionyl-leucyl-phenylalanine was enhanced in a dose-dependent manner, the response to the particulate stimulus, latex beads, was abolished.

The effect of long-acting beta2-agonists on airway inflammation in asthmatic patients

Early observations suggested that the inhibition by long-acting beta2-agonists (LABAs) of non-specific bronchial hyperresponsiveness following allergen challenge was unrelated to bronchodilation or functional antagonism and might be a reflection of anti-inflammatory activity. Investigation of the effect of LABAs on airway inflammatory responses has demonstrated an inhibition of eosinophil recruitment in allergen challenge studies. Nevertheless, results from biopsy and other studies suggest that the chronic inflammatory process in asthma patients is unaffected by these drugs. There is no evidence from biopsy studies that LABAs are pro-inflammatory or that they mask existing inflammation. The beneficial effects of LABAs in allergen challenge are probably mediated through stabilization of mast cells. Recent evidence suggests that LABAs may reduce numbers of neutrophils and their associated markers; this observation needs to be confirmed in future studies and its relevance to the treatment of asthma determined.

An antiinflammatory effect of salmeterol, a long-acting beta(2) agonist, assessed in airway biopsies and bronchoalveolar lavage in asthma

The addition of long-acting beta(2) agonists to inhaled corticosteroid (ICS) therapy in symptomatic patients with asthma improves clinical status more than increasing the dose of ICS. It has been suggested that these benefits could be at the cost of an increase in airway inflammation, but few histopathological studies have been performed in the relevant group. In a double-blind, parallel-group, placebo-controlled study, we randomly assigned 50 symptomatic patients with asthma who were receiving ICS (range, 100 -500 microgram/d) to 12 wk of supplementary treatment with salmeterol (50 microgram twice daily) or fluticasone (100 microgram twice daily) or placebo. Bronchial biopsies and BAL were obtained from 45 patients before and after treatment and analyzed. After treatment with salmeterol there was no deterioration of airway inflammation as assessed by mast cells, lymphocytes, or macrophages in BAL or biopsies, but rather a significant fall in EG1-positive eosinophils in the lamina propria (from a median 18.3 to 7.6 cells/mm, p = 0.01), which was not seen after treatment with fluticasone. The only cellular effect of added fluticasone was a decrease in BAL lymphocyte activation. There was a concurrent improvement in clinical status, more marked with salmeterol than with increased ICS. Thus, adding salmeterol to ICS is not associated with increased "allergic" airway inflammation, but conversely with a complementary antieosinophil effect.

Effects of interleukin-10 and modulators of cyclic AMP formation on endotoxin-induced inflammation in rat lung

The aim of this study was to investigate the effects of IL-10, a cell permeable analogue of cyclic AMP, dibutyryl-cAMP (db-cAMP), modulators of intracellular cyclic AMP such as phosphodiesterase (PDE) inhibitors and a beta 2-adrenoceptor agonist, salmeterol, on pulmonary inflammation following acute lung injury induced by endotoxin exposure in rats. Pulmonary inflammation was induced in adult Wistar rats by a 60-min exposure to endotoxin (lipopolysaccharide, LPS, 100 micrograms/mL). 4 h later bronchoalveolar lavage (BAL) was performed. The PDE inhibitors, rolipram (3 and 5 mg/kg) and theophylline (30 and 100 mg/kg) inhibited neutrophil recruitment, TNF-alpha release and cellular activation in BAL. Salmeterol (0.5 mg/mL) and IL-10 (0.1 microgram) only inhibit TNF-alpha increase in the BAL fluid and db-AMPc (2.5 micrograms/rat) was ineffective. The present data show that the selective PDE4 inhibitor, rolipram, and the non-selective PDE inhibitor, theophylline, markedly reduced the pulmonary inflammation associated with acute lung injury in the rat. These effects may be mediated in part by IL-10 rather than by cyclic AMP, as demonstrated by the potent inhibitory activity of exogenous IL-10 on the increase in TNF-alpha release in BAL fluid of rats exposed to LPS.

Effect of rolipram and dibutyryl cyclic AMP on resequestration of cytosolic calcium in FMLP-activated human neutrophils

1. We have investigated the effects of the selective phosphodiesterase (PDE) type 4 inhibitor, rolipram (0.01-1 microM) on cytosolic Ca2+ fluxes in FMLP-activated human neutrophils, as well as on superoxide production by, and release of elastase from, these cells. 2. Cytosolic Ca2+ fluxes were measured by use of fura-2 spectrofluorimetry in combination with a radiometric procedure that enables distinction between net efflux and influx of the cation. Superoxide production and elastase release were measured by lucigenin-enhanced chemiluminescence and a colorimetric procedure, respectively. 3. Pretreatment of neutrophils with rolipram did not affect the FMLP-activated release of Ca2+ from intracellular stores, but was associated with dose-related acceleration of the rate of decline in fura-2 fluorescence and with decreased efflux, as well as store-operated influx of 45Ca2+, indicative of enhancement of resequestration of the cation by the endo-membrane Ca2+-ATPase. 4. Inhibition of superoxide production and elastase release was observed at concentrations of rolipram which accelerated the clearance of Ca2+ from the cytosol of FMLP-activated neutrophils. 5. These effects of rolipram on FMLP-activated Ca2+ fluxes, superoxide generation and elastase release were mimicked by pretreatment of neutrophils with dibutyryl cyclic AMP (0.5-4 mM), while theophylline (10-150 microM), a non-specific PDE inhibitor, as well as the beta2-agonist, salbutamol, were less effective. 6. We conclude that rolipram deactivates FMLP-stimulated human neutrophils by enhancement of cyclic AMP-dependent resequestration of cytosolic Ca2+.