Current and novel bronchodilators in respiratory disease

M2 Muscarinic Receptor-Dependent Contractions of Airway Smooth Muscle are Inhibited by Activation of β-Adrenoceptors

Beta-adrenoceptor (β-AR) agonists inhibit cholinergic contractions of airway smooth muscle (ASM), but the underlying mechanisms are unclear. ASM cells express M3 and M2 muscarinic receptors, but the bronchoconstrictor effects of acetylcholine are believed to result from activation of M3Rs, while the role of the M2Rs is confined to offsetting β-AR-dependent relaxations. However, a profound M2R-mediated hypersensitization of M3R-dependent contractions of ASM was recently reported, indicating an important role for M2Rs in cholinergic contractions of ASM. Here, we investigated if M2R-dependent contractions of murine bronchial rings were inhibited by activation of β-ARs. M2R-dependent contractions were apparent at low frequency (2Hz) electric field stimulation (EFS) and short (10s) stimulus  intervals. The β1-AR agonist, denopamine inhibited EFS-evoked contractions of ASM induced by reduction in stimulus interval from 100 to 10 s and was more effective at inhibiting contractions evoked by EFS at 2 than 20 Hz. Denopamine also abolished carbachol-evoked contractions that were resistant to the M3R antagonist 4-DAMP, similar to the effects of the M2R antagonists, methoctramine and AFDX-116. The inhibitory effects of denopamine on EFS-evoked contractions of ASM were smaller in preparations taken from M2R ^-/- mice, compared to wild-type (WT) controls. In contrast, inhibitory effects of the β3-AR agonist, BRL37344, on EFS-evoked contractions of detrusor strips taken from M2R ^-/- mice were greater than WT controls. These data suggest that M2R-dependent contractions of ASM were inhibited by activation of β1-ARs and that genetic ablation of M2Rs decreased the efficacy of β-AR agonists on cholinergic contractions.

Utilization Patterns and Trends in the Use of Medications for Asthma in a Cohort of Colombian Patients

Purpose

Asthma affects approximately 358 million people worldwide. This study aimed to determine the trend for the use of medications intended to treat asthma in a group of patients affiliated with the Colombian health system.

Patients and Methods

This was a retrospective study on prescription patterns of medications used to treat asthma in patients over 5 years of age between 2017 and 2019. Sociodemographic variables, medications used and combinations, the persistence of use, and prescribing physicians were considered. Data were obtained from a drug-dispensing database from Colombia.

Results

A total of 10,706 people diagnosed with asthma were identified, including predominantly females (56.8%), with a mean age of 32.2 ± 26.1 years. At the beginning of the follow-up, 53.2% of patients aged 5–11 years were receiving monotherapy, with a mean of 1.5 ± 0.6 drugs/patient, especially inhaled corticosteroids (ICSs; 55.9%) and short-acting β-agonists (SABAs; 55.6%). Moreover, in patients older than 12 years, 53.5% were treated with monotherapy, with a mean of 1.6 ± 0.7 drugs/patient, 45.9% of whom were on SABAs, while 37.1% were on ICSs. Between 63.0% and 83.6% of patients were treated by a general practitioner. 12.5% of patients (n = 495) received triple therapy (ICS/LABA + LAMA [long-acting antimuscarinic]), particularly fluticasone/salmeterol + tiotropium.

Conclusion

The identification of treatment patterns will allow physicians and decision makers to implement strategies in order to promote adherence to treatment and improve asthma medication use.

Functional expression of NaV1.7 channels in freshly dispersed mouse bronchial smooth muscle cells

Isolated smooth muscle cells (SMC) from mouse bronchus were studied using the whole-cell patch clamp technique at ~21oC. Stepping from -100 mV to -20 mV evoked inward currents of mean amplitude -275 pA. These inactivated (tau=1.1 ms) and were abolished when external Na+ was substituted with N-Methyl-D-glucamine. In current-voltage protocols, current peaked at -10 mV and reversed between +20 and +30 mV. The V1/2s of activation and inactivation were -25 & -86 mV, respectively. The current was highly sensitive to tetrodotoxin (IC50=1.5 nM) and the NaV1.7 subtype selective blocker, PF-05089771 (IC50=8.6 nM), consistent with NaV1.7 as the underlying pore-forming a subunit. Two NaV1.7-selective antibodies caused membrane-delineated staining of isolated SMC, as did a non-selective pan-NaVantibody. RT-PCR, performed on groups of ~15 isolated SMC, revealed transcripts for NaV1.7 in 7/8 samples. Veratridine (30 mM), a non-selective NaV channel activator, reduced peak current evoked by depolarization but induced a sustained current of 40 pA. Both effects were reversed by tetrodotoxin (100 nM). In tension experiments veratridine (10 mM) induced contractions that were entirely blocked by atropine (1 mM). However, in the presence of atropine, veratridine was able to modulate the pattern of activity induced by a combination of U-46619 (a thromboxane A2 mimetic) & PGE2(prostaglandin E2), by eliminating bursts in favour of sustained phasic contractions. These effects were readily reversed to control-like activity by tetrodotoxin (100 nM). In conclusion, mouse bronchial SMC functionally express NaV1.7 channels that are capable of modulating contractile activity, at least under experimental conditions.

Contribution of Postjunctional M2 Muscarinic Receptors to Cholinergic Nerve-Mediated Contractions of Murine Airway Smooth Muscle

Postjunctional M2Rs on airway smooth muscle (ASM) outnumber M3Rs by a ratio of 4:1 in most species, however, it is the M3Rs that are thought to mediate the bronchoconstrictor effects of acetylcholine. In this study, we describe a novel and profound M2R-mediated hypersensitization of M3R-dependent contractions of ASM at low stimulus frequencies.. Contractions induced by 2Hz EFS were augmented by > 2.5-fold when the stimulus interval was reduced from 100 to 10 s. This effect was reversed by the M2R antagonists, methoctramine, and AFDX116, and was absent in M2R null mice. The M3R antagonist 4-DAMP abolished the entire response in both WT and M2R KO mice. The M2R-mediated potentiation of EFS-induced contractions was not observed when the stimulus frequency was increased to 20 Hz. A subthreshold concentration of carbachol enhanced the amplitude of EFS-evoked contractions in WT, but not M2R null mice. These data highlight a significant M2R-mediated potentiation of M3R-dependent contractions of ASM at low frequency stimulation that could be relevant in diseases such as asthma and COPD.

Nanotechnology based advanced therapeutic strategies for targeting interleukins in chronic respiratory diseases

Both communicable and non-communicable chronic respiratory conditions have accorded for suffering of millions of people of all ages and stated to be leading cause of death, morbidity, economic and social pressures, and disability-adjusted life-years (DALYs) worldwide. These illnesses impair patient's health and negatively impacts families and society, particularly in low and middle-income countries. Chronic respiratory diseases (CRDs) affect different organs of respiratory system, involving airways, parenchyma, and pulmonary vasculature. As the number of respiratory diseases are exponentially escalating but still the stakeholders are not paying attention towards its serious complications. Currently, the treatment being used primarily focusses only on alleviating symptoms of these illness rather delivering the therapeutic agent at target site for optimal care and/or prevention. Lately, extensive research is being conducted on airways and systemic inflammation, oxidative stress, airway, or parenchymal rehabilitation. From which macrophages, neutrophils, and T cells, as well as structural cells as fibroblasts, epithelial, endothelial, and smooth muscle cells have been found to be active participants that are involved in these chronic respiratory diseases. The pathogenesis of all these chronic respiratory diseases gets caused differently via mediators and proteins, including cytokines, chemokines, growth factors and oxidants. Presently, the target of prescription therapies is to reduce the inflammation of airways and relieve the airway contraction. In all studies, cytokines have been found to play an imperative role in fostering chronic airway inflammation and remodelling. Owing to the limitations of conventional treatments, the current review aims to summarize the current knowledge about the chronic respiratory disease and discuss further about the various conventional methods that can be used for treating this ailment. Additionally, it also highlights and discusses about the advanced drug delivery system that are being used for targeting the interleukins for the treatment of CRDs.

Prospects for COPD treatment

The management of chronic obstructive pulmonary disease (COPD) is fundamentally still heavily dependent on the use of bronchodilators and corticosteroids. Therefore, there is a need for alternative, more effective and safer therapeutic approaches. In particular, since inflammation in COPD lungs is often poorly responsive to corticosteroid treatment, novel pharmacological anti-inflammatory approaches are needed to optimally treat COPD patients. There have been multiple attempts to develop drugs that inhibit recruitment and activation of inflammatory cells, such as macrophages, neutrophils and T-lymphocytes, in the lungs of patients with COPD or target inflammatory mediators that are important in the recruitment or activation of these inflammatory cells or released by such cells. This review article focuses on novel classes of anti-inflammatory drugs that have already been tested in humans as possible treatments for patients with COPD.

Systemic Corticosteroid-Related Complications and Costs in Adults with Persistent Asthma

BACKGROUND

Systemic corticosteroids (SCS) may cause complications for patients with asthma.

OBJECTIVE

We sought to better understand the burden of SCS use in persistent asthma, including health care costs.

METHODS

Adult patients with persistent asthma were identified in the IBM MarketScan Databases from January 2003 to July 2016. The index date was set as the first SCS prescription for SCS users or an algorithm-matched date for non-SCS users. Patients were required to have ≥1 year of data before and after the index date. Based on the number of SCS claims in the first year after index, patients were categorized into 3 SCS groups: 0 SCS claims, 1 to 3 claims, and 4+ claims. Inverse probability of treatment weights were applied to adjust for differences between SCS and non-SCS users. Analyses included weighted and multivariate modeling to assess SCS-related complications and costs during a 3-year follow-up.

RESULTS

A total of 86,786 SCS users (1-3 claims: 76,690; 4+ claims: 10,096) and 91,409 non-SCS users were included; 45% remained 3 years after index. In multivariate analysis, the 3-year risk of developing any chronic complication was 6% greater for those with 1 to 3 claims and 26% greater for those with 4+ claims compared with non-SCS users (P < .001). Multivariate-adjusted health care costs over 3 years were significantly greater as 4+ users incurred $22,311 greater total costs, $4627 greater asthma-related costs, and $2647 greater chronic complication-related costs than non-SCS users (P < .001).

CONCLUSIONS

In this study, adults with persistent asthma receiving SCS treatment had greater odds of complications and greater associated costs over 3 years than matched non-SCS asthma patients.

The future of bronchodilation: looking for new classes of bronchodilators

Available bronchodilators can satisfy many of the needs of patients suffering from airway disorders, but they often do not relieve symptoms and their long-term use raises safety concerns. Therefore, there is interest in developing new classes that could help to overcome the limits that characterise the existing classes.At least nine potential new classes of bronchodilators have been identified: 1) selective phosphodiesterase inhibitors; 2) bitter-taste receptor agonists; 3) E-prostanoid receptor 4 agonists; 4) Rho kinase inhibitors; 5) calcilytics; 6) agonists of peroxisome proliferator-activated receptor-γ; 7) agonists of relaxin receptor 1; 8) soluble guanylyl cyclase activators; and 9) pepducins. They are under consideration, but they are mostly in a preclinical phase and, consequently, we still do not know which classes will actually be developed for clinical use and whether it will be proven that a possible clinical benefit outweighs the impact of any adverse effect.It is likely that if developed, these new classes may be a useful addition to, rather than a substitution of, the bronchodilator therapy currently used, in order to achieve further optimisation of bronchodilation.

Relaxant effect of Curcuma longa on rat tracheal smooth muscle and its possible mechanisms

CONTEXT

Turmeric is a spice obtained from the root of Curcuma longa L. (Zingiberaceae) with anti-aging, anticancer, anti-Alzheimer's disease, antioxidant and other medicinal properties.

OBJECTIVE

The relaxant effect of C. longa on rat tracheal smooth muscle and its possible mechanisms were investigated in this study.

MATERIALS AND METHODS

The relaxant effects of four cumulative concentrations of hydro-ethanol extract of C. longa (6.25, 12.5, 25, 50 mg/mL) were studied on tracheal smooth muscle precontracted by methacholine or KCl in non-incubated or incubated with different substances including propranolol, diltiazem, L-NAME, glibenclamide, atropine, chlorpheniramine, indomethacin and papaverine. The duration of the study was 84 days.

RESULTS

In non-incubated tracheal smooth muscle, the extract of C. longa showed significant concentration-dependent relaxant effects (p < 0.001 for all concentrations on both KCl and methacholine-induced contraction). There was no significant difference in the relaxant effects between C. longa and theophylline in both methacholine and KCl-induced contraction conditions. In tissues incubated with propranolol, diltiazem, L-NAME and glibenclamide on methacholine-induced contraction and in tissues incubated with atropine, chlorpheniramine, indomethacin and papaverine on KCl-induced contraction, the extract also showed significant concentration-dependent relaxant effects (p < 0.001). EC₅₀ values of C. longa between non-incubated (16.22 ± 0.62) and incubated tissues (atropine: 13.03 ± 0.55, chlorpheniramine: 12.94 ± 0.68, indomethacin: 14.80 ± 0.57 and papaverine: 16.16 ± 1.42) were not significantly different.

CONCLUSIONS

Tracheal smooth muscle relaxant effects of C. longa, were comparable to those of theophylline, which could be due to the presence of methylxanthines or its possible interaction with non-adrenergic non-cholinergic nervous system.

Activation of the sweet taste receptor, T1R3, by the artificial sweetener sucralose regulates the pulmonary endothelium

A hallmark of acute respiratory distress syndrome (ARDS) is pulmonary vascular permeability. In these settings, loss of barrier integrity is mediated by cell-contact disassembly and actin remodeling. Studies into molecular mechanisms responsible for improving microvascular barrier function are therefore vital in the development of therapeutic targets for reducing vascular permeability in ARDS. The sweet taste receptor T1R3 is a G protein-coupled receptor, activated following exposure to sweet molecules, to trigger a gustducin-dependent signal cascade. In recent years, extraoral locations for T1R3 have been identified; however, no studies have focused on T1R3 within the vasculature. We hypothesize that activation of T1R3, in the pulmonary vasculature, plays a role in regulating endothelial barrier function in settings of ARDS. Our study demonstrated expression of T1R3 within the pulmonary vasculature, with a drop in expression levels following exposure to barrier-disruptive agents. Exposure of lung microvascular endothelial cells to the intensely sweet molecule sucralose attenuated LPS- and thrombin-induced endothelial barrier dysfunction. Likewise, sucralose exposure attenuated bacteria-induced lung edema formation in vivo. Inhibition of sweet taste signaling, through zinc sulfate, T1R3, or G-protein siRNA, blunted the protective effects of sucralose on the endothelium. Sucralose significantly reduced LPS-induced increased expression or phosphorylation of the key signaling molecules Src, p21-activated kinase (PAK), myosin light chain-2 (MLC2), heat shock protein 27 (HSP27), and p110α phosphatidylinositol 3-kinase (p110αPI3K). Activation of T1R3 by sucralose protects the pulmonary endothelium from edemagenic agent-induced barrier disruption, potentially through abrogation of Src/PAK/p110αPI3K-mediated cell-contact disassembly and Src/MLC2/HSP27-mediated actin remodeling. Identification of sweet taste sensing in the pulmonary vasculature may represent a novel therapeutic target to protect the endothelium in settings of ARDS.

Inhaled efficacious dose translation from rodent to human: A retrospective analysis of clinical standards for respiratory diseases

Clinical pharmacologists and toxicologists are often faced with predicting equivalent dosages for humans from biological observations in laboratory animals. Allometric scaling has been used extensively as the basis for extrapolation of drug dosage that might be expected to produce the equivalent biological effects. Allometry is the study of size and its consequences and it is based on the anatomical, physiological, and biochemical similarities between animals. In this review, retrospective analyses have been performed based on data reported in the literature in an attempt to determine the utility of allometric scaling for human dose projections from pre-clinical data for compounds that are delivered by inhalation. The limited pre-clinical efficacy data available on inhaled drugs that are also used clinically supports the current method of scaling using a fixed allometric exponent of 0.67. An example of the utility of the human inhaled dose projections for planning inhaled toxicology studies is also presented.

Dry Powder and Nebulized Aerosol Inhalation of Pharmaceuticals Delivered to Mice Using a Nose-only Exposure System

Obstructive respiratory diseases like asthma and chronic obstructive pulmonary disease (COPD) are currently treated by inhaled anti-inflammatory and bronchodilator drugs. Despite the availability of multiple treatments, both diseases are growing public health concerns. The majority of asthma patients are well controlled on current inhaled therapies but a substantial number of patients with severe asthma are not. Asthma affects an estimated 300 million people worldwide and approximately 20 percent have a severe form of the disease. In contrast to asthma, there are few effective therapies for COPD. An estimated 10% of the population has COPD and the trend in death rates is increasing for COPD while decreasing for other major diseases. Although developing drugs for inhaled delivery is challenging, the nose-only inhalation unit enables direct delivery of novel drugs to the lung of rodents for pre-clinical efficacy and safety/toxicology studies. Inhaled drug delivery has multiple advantages for respiratory diseases, where high concentration in the lung improves efficacy and minimizes systemic side effects. Inhaled corticosteroids and bronchodilators benefit from these advantages and inhaled delivery may also hold potential for future biologic therapies. The inhalation unit described herein can generate, sample for characterization, and uniformly deposit a drug aerosol in the lungs of rodents. This enables the pre-clinical determination of the efficacy and safety of drug doses deposited in the lungs of rodents, key data required before initiating clinical development.

Investigational beta-2 adrenergic agonists for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Long-acting bronchodilators are pivotal in the therapeutic management of COPD patients with moderate-to-severe airflow obstruction. New ultra-long-acting β2-agnoists (ultra-LABAs) have been developed, some of which have been licensed for use as monotherapy and/or in combination with other bronchodilators or inhaled corticosteroids, for use in COPD patients with persistent symptoms and worsening airflow limitation. These new agents are faster in onset and have a prolonged duration of action, with a similar safety profile to the traditional twice-daily bronchodilators which may have an impact on patient concordance. Areas covered: A number of these ultra-LABAs are still under development and bi-functional hybrid molecules containing regions functioning as β2-agonists, and as muscarinic agonists (MABAs) has been developed. This review summarizes these (excluding the licensed ultra-LABAs) with attention on phase II studies data available to-date on their pharmacological profiles, clinical efficacy and safety, and future perspectives. Expert opinion: Despite all the new agents' available, the challenges that persist include any differences in efficacy and safety between the various possible LAMA/LABA combinations, relative advantages of MABAs over fixed-dose LAMA/LABAs, and the impact of these new molecules in terms of long term safety, especially in certain populations in co-morbidities frequently associated with COPD.

Serelaxin Elicits Bronchodilation and Enhances β-Adrenoceptor-Mediated Airway Relaxation

Treatment with β-adrenoceptor agonists does not fully overcome the symptoms associated with severe asthma. Serelaxin elicits potent uterine and vascular relaxation via its cognate receptor, RXFP1, and nitric oxide (NO) signaling, and is being clinically evaluated for the treatment of acute heart failure. However, its direct bronchodilator efficacy has yet to be explored. Tracheal rings were prepared from male Sprague-Dawley rats (250–350 g) and tricolor guinea pigs, and precision cut lung slices (PCLSs) containing intrapulmonary airways were prepared from rats only. Recombinant human serelaxin (rhRLX) alone and in combination with rosiglitazone (PPARγ agonist; recently described as a novel dilator) or β-adrenoceptor agonists (isoprenaline, salbutamol) were added either to pre-contracted airways, or before contraction with methacholine or endothelin-1. Regulation of rhRLX responses by epithelial removal, indomethacin (cyclooxygenase inhibitor), L-NAME (nitric oxide synthase inhibitor), SQ22536 (adenylate cyclase inhibitor) and ODQ (guanylate cyclase inhibitor) were also evaluated. Immunohistochemistry was used to localize RXFP1 to airway epithelium and smooth muscle. rhRLX elicited relaxation in rat trachea and PCLS, more slowly than rosiglitazone or isoprenaline, but potentiated relaxation to both these dilators. It markedly increased β-adrenoceptor agonist potency in guinea pig trachea. rhRLX, rosiglitazone, and isoprenaline pretreatment also inhibited the development of rat tracheal contraction. Bronchoprotection by rhRLX increased with longer pre-incubation time, and was partially reduced by epithelial removal, indomethacin and/or L-NAME. SQ22536 and ODQ also partially inhibited rhRLX-mediated relaxation in both intact and epithelial-denuded trachea. RXFP1 expression in the airways was at higher levels in epithelium than smooth muscle. In summary, rhRLX elicits large and small airway relaxation via epithelial-dependent and -independent mechanisms, likely via RXFP1 activation and generation of NO, prostaglandins and cAMP/cGMP. rhRLX also enhanced responsiveness to other dilators, suggesting its potential as an alternative or add-on therapy for severe asthma.

Novel relaxant effects of RPL554 on guinea pig tracheal smooth muscle contractility

BACKGROUND AND PURPOSE

We investigated the effectiveness of RPL554, a dual PDE3 and 4 enzyme inhibitor, on airway smooth muscle relaxation and compared it with that induced by salbutamol, ipratropium bromide, glycopyrrolate or their combination on bronchomotor tone induced by different spasmogenic agents.

EXPERIMENTAL APPROACH

Guinea pig tracheal preparations were suspended under 1 g tension in Krebs-Henseleit solution maintained at 37°C and aerated with 95% O2 /5% CO2 and incubated in the presence of indomethacin (5 μM). Relaxation induced by cumulative concentrations of muscarinic receptor antagonists (ipratropium bromide or glycopyrrolate), β2 -adrenoceptor agonists (salbutamol or formoterol), PDE3 inhibitors (cilostamide, cilostazol or siguazodan) or a PDE4 inhibitor (roflumilast) was evaluated in comparison with RPL554. Maximal relaxation was calculated (% Emax papaverine) and expressed as mean ± SEM.

KEY RESULTS

Bronchomotor tone induced by the various spasmogens was reduced by the different bronchodilators to varying degrees. RPL554 (10-300 μM) caused near maximum relaxation irrespective of the spasmogen examined, whereas the efficacy of the other relaxant agents varied according to the contractile stimulus used. During the evaluation of potential synergistic interactions between bronchodilators, RPL554 proved superior to salbutamol when either was combined with muscarinic receptor antagonists.

CONCLUSIONS AND IMPLICATIONS

RPL554 produced near maximal relaxation of highly contracted respiratory smooth muscle and provided additional relaxation compared with that produced by other clinically used bronchodilator drugs. This suggests that RPL554 has the potential to produce additional beneficial bronchodilation over and above that of maximal clinical doses of standard bronchodilators in highly constricted airways of patients.

β2-Adrenergic agonists attenuate organic dust-induced lung inflammation

Agricultural dust exposure results in significant lung inflammation, and individuals working in concentrated animal feeding operations (CAFOs) are at risk for chronic airway inflammatory diseases. Exposure of bronchial epithelial cells to aqueous extracts of hog CAFO dusts (HDE) leads to inflammatory cytokine production that is driven by protein kinase C (PKC) activation. cAMP-dependent protein kinase (PKA)-activating agents can inhibit PKC activation in epithelial cells, leading to reduced inflammatory cytokine production following HDE exposure. β2-Adrenergic receptor agonists (β2-agonists) activate PKA, and we hypothesized that β2-agonists would beneficially impact HDE-induced adverse airway inflammatory consequences. Bronchial epithelial cells were cultured with the short-acting β2-agonist salbutamol or the long-acting β2-agonist salmeterol prior to stimulation with HDE. β2-Agonist treatment significantly increased PKA activation and significantly decreased HDE-stimulated IL-6 and IL-8 production in a concentration- and time-dependent manner. Salbutamol treatment significantly reduced HDE-induced intracellular adhesion molecule-1 expression and neutrophil adhesion to epithelial cells. Using an established intranasal inhalation exposure model, we found that salbutamol pretreatment reduced airway neutrophil influx and IL-6, TNF-α, CXCL1, and CXCL2 release in bronchoalveolar lavage fluid following a one-time exposure to HDE. Likewise, when mice were pretreated daily with salbutamol prior to HDE exposure for 3 wk, HDE-induced neutrophil influx and inflammatory mediator production were also reduced. The severity of HDE-induced lung pathology in mice repetitively exposed to HDE for 3 wk was also decreased with daily salbutamol pretreatment. Together, these results support the need for future clinical investigations to evaluate the utility of β2-agonist therapies in the treatment of airway inflammation associated with CAFO dust exposure.

New combinations in the treatment of COPD: rationale for aclidinium-formoterol

The current guidelines on chronic obstructive pulmonary disease (COPD) recommend the prominent use of bronchodilators, including long-acting β₂-agonists (LABAs) and long-acting muscarinic antagonists (LAMAs), while inhaled corticosteroids are recommended only in patients with severe disease or frequent exacerbations. LABA–LAMA combinations are indicated when single bronchodilators are insufficient to control COPD. A number of LABA–LAMA combinations are available, based on twice-daily or once-daily administration according to the 12- or 24-hour duration of action, respectively. The aclidinium–formoterol combination is based on the new LAMA aclidinium bromide, which has a high selectivity for M₃ muscarinic receptors and a fast onset of action, and the well-known LABA formoterol. Both drugs require twice-daily administration. The fixed-dose combination of aclidinium 400 μg/formoterol 12 μg has shown in randomized controlled trials fast and sustained bronchodilation that was greater than either monotherapy and provided clinically significant improvements in dyspnea and health status compared with placebo, also reducing the use of rescue medications. The overall incidence of adverse events was low and comparable to placebo. These data define the aclidinium–formoterol fixed-dose combination as a new treatment option for patients with COPD. The need for twice-daily administration could be an apparent disadvantage compared to the available once-daily LABA–LAMA combinations, but the immediately perceived benefit in reducing dyspnea due to the fast onset of action, as well as reported correct patient use and satisfaction with the Genuair inhaler might prove useful in favoring adherence.

Striving for optimal bronchodilation: focus on olodaterol

β2-agonists were introduced in the 1940s as bronchodilators to be used in obstructive respiratory diseases. Long-acting β2-agonists have been a mainstay of bronchodilating treatment for decades. Recently, agents extending their effect to 24 hours and thus allowing the once-daily administration were introduced, defined as very-long-acting β2-agonists. Olodaterol is a new very-long-acting β2-agonist that has been shown, in controlled trials, to improve lung function as well as clinical outcomes and quality of life. Most of these trials included patients with moderate, severe, or very severe chronic obstructive pulmonary disease (COPD). Olodaterol has a rapid onset of action (comparable to formoterol) and provides bronchodilation over 24 hours. In controlled trials, olodaterol was shown to be as effective as formoterol twice daily, but significantly superior in terms of quality of life in patients with COPD. The safety profile of olodaterol was very good, with a rate of adverse events, including the cardiac events that are particularly important for β2-agonists, comparable to placebo. Also, the efficiency of the Respimat(®) device concurs to the effectiveness of treatment.

Carvedilol binding to β2-adrenergic receptors inhibits CFTR-dependent anion secretion in airway epithelial cells

Carvedilol functions as a nonselective β-adrenergic receptor (AR)/α1-AR antagonist that is used for treatment of hypertension and heart failure. Carvedilol has been shown to function as an inverse agonist, inhibiting G protein activation while stimulating β-arrestin-dependent signaling and inducing receptor desensitization. In the present study, short-circuit current (Isc) measurements using human airway epithelial cells revealed that, unlike β-AR agonists, which increase Isc, carvedilol decreases basal and 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate-stimulated current. The decrease in Isc resulted from inhibition of the cystic fibrosis transmembrane conductance regulator (CFTR). The carvedilol effect was abolished by pretreatment with the β2-AR antagonist ICI-118551, but not the β1-AR antagonist atenolol or the α1-AR antagonist prazosin, indicating that its inhibitory effect on Isc was mediated through interactions with apical β2-ARs. However, the carvedilol effect was blocked by pretreatment with the microtubule-disrupting compound nocodazole. Furthermore, immunocytochemistry experiments and measurements of apical CFTR expression by Western blot analysis of biotinylated membranes revealed a decrease in the level of CFTR protein in monolayers treated with carvedilol but no significant change in monolayers treated with epinephrine. These results demonstrate that carvedilol binding to apical β2-ARs inhibited CFTR current and transepithelial anion secretion by a mechanism involving a decrease in channel expression in the apical membrane.

Vasoactive Intestinal Peptide for Diagnosing Exacerbation in Chronic Obstructive Pulmonary Disease

BACKGROUND

Vasoactive intestinal peptide (VIP) is the most abundant neuropeptide in the lung. VIP has been linked to pulmonary arterial hypertension and hypoxia.

OBJECTIVES

We aimed to assess circulating VIP levels at exacerbation and at stable chronic obstructive pulmonary disease (COPD) and to evaluate the diagnostic performance in a well-characterized cohort of COPD patients.

METHODS

The nested cohort study included patients with Global Initiative for Chronic Obstructive Lung Disease stage II-IV. Patients were examined at stable state and at acute exacerbation of COPD (AE-COPD), and dedicated serum was collected at both conditions. Serum VIP levels were determined by enzyme-linked immunosorbent assay. Diagnostic accuracy was analyzed by receiver operating characteristic curve and area under the curve (AUC).

RESULTS

Patients with acute exacerbation (n = 120) and stable COPD (n = 163) had similar characteristics at baseline. Serum VIP levels did not correlate with oxygen saturation at rest (p = 0.722) or at exercise (p = 0.168). Serum VIP levels were significantly higher at AE-COPD (130.25 pg/ml, 95% CI 112.19-151.83) as compared to stable COPD (40.07 pg/ml, 95% CI 37.13-43.96, p < 0.001). The association of increased serum VIP with AE-COPD remained significant after propensity score matching (p < 0.001). Analysis of the Youden index indicated the optimal serum VIP cutoff value as 56.6 pg/ml. The probability of AE-COPD was very low if serum VIP was ≤35 pg/ml (sensitivity >90%) and very high if serum VIP was ≥88 pg/ml (specificity >90%). Serum VIP levels presented a robust performance to diagnose AE-COPD (AUC 0.849, 95% CI 0.779-0.899).

CONCLUSIONS

Increased serum VIP levels are associated with AE-COPD.

Pharmacology of novel treatments for COPD: are fixed dose combination LABA/LAMA synergistic?

Bronchodilators are mainstay for the symptomatic treatment of chronic obstructive pulmonary disease (COPD) and the introduction of long-acting bronchodilators has led to an improvement in the maintenance treatment of this disease. Various clinical trials have evaluated the effects of fixed dose long-acting β2-agonists (LABA)/long-acting anti-muscarinics (LAMA) combinations and documented greater improvements in spirometry but such improvements do not always translate to greater improvements in symptom scores or reduction in the rates of exacerbation compared with a single component drug. An analysis of whether this significantly greater change in spirometry with combination therapy is additive or synergistic was undertaken and is the subject of this review. Bronchodilators are not disease modifiers and whilst glucocorticosteroids have been shown to reduce rates of exacerbation in moderate to severe COPD, the increase risk of pneumonia and bone fractures is a motivation enough to warrant developing novel anti-inflammatory and disease-modifying drugs and with the expectation of positive outcomes.

Effect of roflumilast on exacerbations in patients with severe chronic obstructive pulmonary disease uncontrolled by combination therapy (REACT): a multicentre randomised controlled trial

BACKGROUND

Roflumilast reduces exacerbations in patients with severe chronic obstructive pulmonary disease. Its effect in patients using fixed combinations of inhaled corticosteroids and longacting β2 agonists is unknown. We postulated that roflumilast would reduce exacerbations in patients with severe chronic obstructive pulmonary disease at risk for exacerbations, even in combination with inhaled corticosteroid and longacting β2 agonist treatment.

METHODS

For this 1-year double-blind, placebo-controlled, parallel group, multicentre, phase 3-4 trial, the Roflumilast and Exacerbations in patients receiving Appropriate Combination Therapy (REACT) study, we enrolled patients with severe chronic obstructive pulmonary disease from 203 centres (outpatient clinics, hospitals, specialised pulmonologists, and family doctors) in 21 countries. Eligible patients were 40 years of age or older with a smoking history of at least 20 pack-years and a diagnosis of chronic obstructive pulmonary disease with severe airflow limitation, symptoms of chronic bronchitis, and at least two exacerbations in the previous year. We used a computerised central randomisation system to randomly assign patients in a 1:1 ratio to the two treatment groups: roflumilast 500 μg or placebo given orally once daily together with a fixed inhaled corticosteroid and longacting β2 agonist combination. Background tiotropium treatment was allowed. All patients and investigators were masked to group assignment. The primary outcome was the rate of moderate to severe chronic obstructive pulmonary disease exacerbations per patient per year, analysed by intention to treat. This study is registered with ClinicalTrials.gov, number NCT01329029.

FINDINGS

Between April 3, 2011, and May 27, 2014, we enrolled 1945 eligible participants and randomly assigned 973 to the roflumilast group and 972 to the placebo group. The rate of moderate-to-severe chronic obstructive pulmonary disease exacerbations was 13·2% lower in the roflumilast group than in the placebo group according to a Poisson regression analysis (roflumilast 0·805 vs placebo 0·927; rate ratio [RR] 0·868 [95% CI 0·753-1·002], p=0·0529), and 14·2% lower according to a predefined sensitivity analysis using negative binomial regression (0·823 vs 0·959; 0·858 [0·740-0·995], p=0·0424). Adverse events were reported by 648 (67%) of 968 patients receiving roflumilast and by 572 (59%) of 967 patients in the placebo group; adverse event-associated patient withdrawal from the study was also more common in the roflumilast group (104/968 [11%]) than in the placebo group (52/967 [5%]). The most frequently reported serious adverse events were chronic obstructive pulmonary disease exacerbations and pneumonia, and 17 (1·8%) deaths occurred in the roflumilast group compared with 18 (1·9%) in the placebo group.

INTERPRETATION

Our findings suggest that roflumilast reduces exacerbations and hospital admissions in patients with severe chronic obstructive pulmonary disease and chronic bronchitis who are at risk of frequent and severe exacerbations despite inhaled corticosteroid and longacting β2 agonist therapy, even in combination with tiotropium.

FUNDING

Takeda.

Quantification of beta adrenergic receptor subtypes in beta-arrestin knockout mouse airways

In allergic asthma Beta 2 adrenergic receptors (β₂ARs) are important mediators of bronchorelaxation and, paradoxically, asthma development. This contradiction is likely due to the activation of dual signaling pathways that are downstream of G proteins or β-arrestins. Our group has recently shown that β-arrestin-2 acts in its classical role to desensitize and constrain β₂AR-induced relaxation of both human and murine airway smooth muscle. To assess the role of β-arrestins in regulating β₂AR function in asthma, we and others have utilized β-arrestin-1 and -2 knockout mice. However, it is unknown if genetic deletion of β-arrestins in these mice influences β₂AR expression in the airways. Furthermore, there is lack of data on compensatory expression of βAR subtypes when either of the β-arrestins is genetically deleted, thus necessitating a detailed βAR subtype expression study in these β-arrestin knockout mice. Here we standardized a radioligand binding methodology to characterize and quantitate βAR subtype distribution in the airway smooth muscle of wild-type C57BL/6J and β-arrestin-1 and β-arrestin-2 knockout mice. Using complementary competition and single-point saturation binding assays we found that β₂ARs predominate over β₁ARs in the whole lung and epithelium-denuded tracheobronchial smooth muscle of C57BL/6J mice. Quantification of βAR subtypes in β-arrestin-1 and β-arrestin-2 knockout mouse lung and epithelium-denuded tracheobronchial tissue showed that, similar to the C57BL/6J mice, both knockouts display a predominance of β₂AR expression. These data provide further evidence that β₂ARs are expressed in greater abundance than β₁ARs in the tracheobronchial smooth muscle and that loss of either β-arrestin does not significantly affect the expression or relative proportions of βAR subtypes. As β-arrestins are known to modulate β₂AR function, our analysis of βAR subtype expression in β-arrestin knockout mice airways sets a reference point for future studies exploiting these knockout mice in various disease models including asthma.

Update on ultra-long-acting β agonists in chronic obstructive pulmonary disease

INTRODUCTION

For the last two decades, long-acting β agonists (LABAs) have been a cornerstone in the management of chronic obstructive pulmonary disease (COPD). They relax airway smooth muscle and augment expiratory airflow, which reduces hyperinflation and improves dyspnea, functional capacity and quality of life. In recent years, Indacaterol, a LABA with an ultra-long duration of action (ultra-LABA), which only requires once-daily dosing, was approved by the FDA. The clinical efficacy of indacaterol is comparable, and, in some aspects better, than the currently available LABAs.

AREAS COVERED

This article reviews the pharmacological properties, clinical efficacy, safety and potential role of the ultra-LABAs in COPD management.

EXPERT OPINION

Ultra-LABAs are effective bronchodilators with a prolonged duration of action. By decreasing dosing frequency, ultra-LABAs potentially may improve respiratory medication adherence, which is associated with better survival and less healthcare utilization. In addition to their salubrious benefits, β agonists may produce untoward effects. Increased mortality and hospitalizations among patients with left ventricular heart failure, who were treated with β agonists, has caused concern about their use in patients with COPD and heart disease. Further experience and testing will determine the optimal role of ultra-LABAs in the management of COPD.

Umeclidinium bromide and vilanterol in combination for the treatment of chronic obstructive pulmonary disease

Drugs from the two major classes of bronchodilator; umeclidinium, a long-acting muscarinic antagonist (LAMA), and vilanterol, a long-acting β2 agonist (LABA), have been combined in a single inhaler device for once-daily use in chronic obstructive pulmonary disease (COPD). These drugs have been proven safe and well tolerated in patients with COPD and show an enhanced improvement in FEV1 when compared to either drug in isolation and when compared with an established LAMA drug. In this article, we discuss the data supporting this combination inhaler and also review alternative combined LAMA/LABA options. We discuss where these agents are likely to find a place in the current therapy of COPD and where the future is likely to lead with these and other therapies.

Profile of fluticasone furoate/vilanterol dry powder inhaler combination therapy as a potential treatment for COPD

Currently, there is no cure for chronic obstructive pulmonary disease (COPD). The limited efficacy of current therapies for COPD indicates a pressing need to develop new treatments to prevent the progression of the disease, which consumes a significant amount of health care resources and is an important cause of mortality worldwide. Current national and international guidelines for the management of stable COPD patients recommend the use of inhaled long-acting bronchodilators, inhaled corticosteroids, and their combination for maintenance treatment of moderate to severe stable COPD. Once-daily fluticasone furoate/vilanterol dry powder inhaler combination therapy has recently been approved by the US Food and Drug Administration and the European Medicines Agency as a new regular treatment for patients with stable COPD. Fluticasone furoate/vilanterol dry powder inhaler combination therapy has been shown to be effective in many controlled clinical trials involving thousands of patients in the regular treatment of stable COPD. This is the first once-daily combination of ultra-long-acting inhaled β₂-agonists and inhaled glucocorticoids that is available for the treatment of stable COPD and has great potential to improve compliance to long-term regular inhaled therapy and hence to improve the natural history and prognosis of COPD patients.