Pharmacological characterisation of the interaction between glycopyrronium bromide and indacaterol fumarate in human isolated bronchi, small airways and bronchial epithelial cells

Drug-Drug Interactions and Synergy: From Pharmacological Models to Clinical Application

This review explores the concept of synergy in pharmacology, emphasizing its importance in optimizing treatment outcomes through the combination of drugs with different mechanisms of action. Synergy, defined as an effect greater than the expected additive effect elicited by individual agents according to specific predictive models, offers a promising approach to enhance therapeutic efficacy while minimizing adverse events. The historical evolution of synergy research, from ancient civilizations to modern pharmacology, highlights the ongoing quest to understand and harness synergistic interactions. Key concepts, such as concentration-response curves, additive effects, and predictive models, are discussed in detail, emphasizing the need for accurate assessment methods throughout translational drug development. Although various mathematical models exist for synergy analysis, selecting the appropriate model and software tools remains a challenge, necessitating careful consideration of experimental design and data interpretation. Furthermore, this review addresses practical considerations in synergy assessment, including preclinical and clinical approaches, mechanism of action, and statistical analysis. Optimizing synergy requires attention to concentration/dose ratios, target site localization, and timing of drug administration, ensuring that the benefits of combination therapy detected bench-side are translatable into clinical practice. Overall, the review advocates for a systematic approach to synergy assessment, incorporating robust statistical analysis, effective and simplified predictive models, and collaborative efforts across pivotal sectors, such as academic institutions, pharmaceutical companies, and regulatory agencies. By overcoming critical challenges and maximizing therapeutic potential, effective synergy assessment in drug development holds promise for advancing patient care. SIGNIFICANCE STATEMENT: Combining drugs with different mechanisms of action for synergistic interactions optimizes treatment efficacy and safety. Accurate interpretation of synergy requires the identification of the expected additive effect. Despite innovative models to predict the additive effect, consensus in drug-drug interactions research is lacking, hindering the bench-to-bedside development of combination therapies. Collaboration among science, industry, and regulation is crucial for advancing combination therapy development, ensuring rigorous application of predictive models in clinical settings.

Precision cut lung slices: an integrated ex vivo model for studying lung physiology, pharmacology, disease pathogenesis and drug discovery

Precision Cut Lung Slices (PCLS) have emerged as a sophisticated and physiologically relevant ex vivo model for studying the intricacies of lung diseases, including fibrosis, injury, repair, and host defense mechanisms. This innovative methodology presents a unique opportunity to bridge the gap between traditional in vitro cell cultures and in vivo animal models, offering researchers a more accurate representation of the intricate microenvironment of the lung. PCLS require the precise sectioning of lung tissue to maintain its structural and functional integrity. These thin slices serve as invaluable tools for various research endeavors, particularly in the realm of airway diseases. By providing a controlled microenvironment, precision-cut lung slices empower researchers to dissect and comprehend the multifaceted interactions and responses within lung tissue, thereby advancing our understanding of pulmonary pathophysiology.

Use of human airway smooth muscle in vitro and ex vivo to investigate drugs for the treatment of chronic obstructive respiratory disorders

Isolated airway smooth muscle has been extensively investigated since 1840 to understand the pharmacology of airway diseases. There has often been poor predictability from murine experiments to drugs evaluated in patients with asthma or chronic obstructive pulmonary disease (COPD). However, the use of isolated human airways represents a sensible strategy to optimise the development of innovative molecules for the treatment of respiratory diseases. This review aims to provide updated evidence on the current uses of isolated human airways in validated in vitro methods to investigate drugs in development for the treatment of chronic obstructive respiratory disorders. This review also provides historical notes on the pioneering pharmacological research on isolated human airway tissues, the key differences between human and animal airways, as well as the pivotal differences between human medium bronchi and small airways. Experiments carried out with isolated human bronchial tissues in vitro and ex vivo replicate many of the main anatomical, pathophysiological, mechanical and immunological characteristics of patients with asthma or COPD. In vitro models of asthma and COPD using isolated human airways can provide information that is directly translatable into humans with obstructive lung diseases. Regardless of the technique used to investigate drugs for the treatment of chronic obstructive respiratory disorders (i.e., isolated organ bath systems, videomicroscopy and wire myography), the most limiting factors to produce high-quality and repeatable data remain closely tied to the manual skills of the researcher conducting experiments and the availability of suitable tissue.

Prolonged airway explant culture enables study of health, disease, and viral pathogenesis

In vitro models play a major role in studying airway physiology and disease. However, the native lung's complex tissue architecture and non-epithelial cell lineages are not preserved in these models. Ex vivo tissue models could overcome in vitro limitations, but methods for long-term maintenance of ex vivo tissue has not been established. We describe methods to culture human large airway explants, small airway explants, and precision-cut lung slices for at least 14 days. Human airway explants recapitulate genotype-specific electrophysiology, characteristic epithelial, endothelial, stromal and immune cell populations, and model viral infection after 14 days in culture. These methods also maintain mouse, rabbit, and pig tracheal explants. Notably, intact airway tissue can be cryopreserved, thawed, and used to generate explants with recovery of function 14 days post-thaw. These studies highlight the broad applications of airway tissue explants and their use as translational intermediates between in vitro and in vivo studies.

Is it preferable to administer a bronchodilator once- or twice-daily when treating COPD?

Nocturnal and early morning symptoms are common and uncomfortable in many patients with COPD, and are likely to affect their long-term outcomes. However, it is still debated whether it is better to give long-acting bronchodilators once- or twice-daily to symptomatic COPD patients. The functional link between circadian rhythms of autonomic tone and airway calibre explains why the timing of administration of bronchodilators in chronic airway diseases can induce different effects when taken at different biological (circadian) times. However, the timing also depends on the pharmacological characteristics of the bronchodilator to be used. Because the profile of bronchodilation produced by once-daily vs. twice-daily long-acting bronchodilators differs throughout 24 h, selecting long-acting bronchodilators may be customized to specific patient preferences based on the need for further bronchodilation in the evening. This is especially helpful for people who experience respiratory symptoms at night or early morning. Compared to placebo, evening bronchodilator administration is consistently linked with persistent overnight improvements in dynamic respiratory mechanics and inspiratory neural drive. The current evidence indicates that nocturnal and early morning symptoms control is best handled by a LAMA taken in the evening. In contrast, it seems preferable to use a LABA for daytime symptoms. Therefore, it can be speculated that combining a LAMA with a LABA can improve bronchodilation and control symptoms better. Both LAMA and LABA must be rapid in their onset of action. Aclidinium/formoterol, a twice-daily combination, is the most studies of the available LAMA/LABA combinations in terms of impact on daytime and nocturnal symptoms.

The Role of Long-Acting Antimuscarinic Agents in the Treatment of Asthma

The journey of using anticholinergics in the treatment of asthma started with anticholinergic-containing plants such as Datura stramonium and Atropa belladonna, followed by ipratropium bromide and continued with tiotropium, glycopyrronium, and umeclidinium. Although antimuscarinics were used in the maintenance treatment of asthma over a century ago, after a long time (since 2014), it has been recommended to be used as an add-on long-acting antimuscarinic agent (LAMA) therapy in the maintenance treatment of asthma. The airway tone controlled by the vagus nerve is increased in asthma. Allergens, toxins, or viruses cause airway inflammation and inflammation-related epithelial damage, increased sensory nerve stimulation, ganglionic and postganglionic acetylcholine (ACh) release by inflammatory mediators, intensification of ACh signaling at M1 and M3 muscarinic ACh receptors (mAChRs), and dysfunction of M2 mAChR. Optimal anticholinergic drug for asthma should effectively block M3 and M1 receptors, but have minimal effect on M2 receptors. Tiotropium, umeclidinium, and glycopyrronium are anticholinergic agents with this feature. Tiotropium has been used in a separate inhaler as an add-on treatment to inhaled corticosteroid (ICS)/long-acting β2-agonist (LABA), and glycopyrronium and umeclidinium have been used in a single inhaler as a combination of ICS/LABA/LAMA in asthma in recent years. Guidelines recommend this regimen as an optimization step for patients with severe asthma before initiating any biologic or systemic corticosteroid therapy. In this review, the history of antimuscarinic agents, their effectiveness and safety in line with randomized controlled trials, and real-life studies in asthma treatment will be discussed according to the current data.

Might It Be Appropriate to Anticipate the Use of Long-Acting Muscarinic Antagonists in Asthma?

A growing number of clinical trials are documenting that adding a long-acting muscarinic antagonist (LAMA) to established asthma treatment with an inhaled corticosteroid (ICS) and a long-acting β₂-agonist (LABA) is a treatment option that improves the health of patients with uncontrolled severe asthma even when therapy is optimized. These favorable results are the reason why the leading guidelines recommend triple therapy with ICS + LABA + LAMA in patients with asthma uncontrolled by medium- to high-dose ICS-LABA. However, we suggest adding LAMAs to ICS-LABAs at an earlier clinical stage. Such action could positively influence airflow limitation, exacerbations, and eosinophilic inflammation, conditions that are associated with acetylcholine (ACh) activity. It could also interrupt the vicious cycle related to a continuous release of ACh leading to the progressive expansion of neuronal plasticity resulting in small airway dysfunction. The utility of an earlier use of triple therapy in asthma should, in any case, be confirmed by statistically powered trials.

The 5T approach in asthma: Triple Therapy Targeting Treatable Traits

Using a therapeutic strategy that is free from traditional diagnostic labels and based on the identification of "treatable traits" (TTs), which are influential in clinical presentations in each patient, might overcome the difficulties in identifying and validating asthma phenotypes and endotypes. Growing evidence is documenting the importance of using the triple therapy with ICS, LABA, and LAMAs in a single inhaler (SITT) in cases of asthma not controlled by ICS/LABA and in the prevention of exacerbations. The identification of TTs may overcome the possibility of using SITT without considering the specific needs of the patient. In effect, it allows a treatment strategy that is closer to the precision strategy now widely advocated for the management of patients with asthma. There are different TTs in asthma that may benefit from treatment with SITT, regardless of guideline recommendations. The airflow limitation and small airway dysfunction are key TTs that are present in different phenotypes/endotypes, do not depend on the degree of T2 inflammation, and respond better than other treatments to SITT. We suggest that the 5T (Triple Therapy Targeting Treatable Traits) approach should be applied to the full spectrum of asthma, not just severe asthma, and, consequently, SITT should begin earlier than currently recommended.

Muscarinic receptor antagonists and airway inflammation: A systematic review on pharmacological models

Airway inflammation is crucial in the pathogenesis of many respiratory diseases, including chronic obstructive pulmonary disease (COPD) and asthma. Current evidence supports the beneficial impact of muscarinic receptor antagonists against airway inflammation from bench-to-bedside. Considering the numerous sampling approaches and the ethical implications required to study inflammation in vivo in patients, the use of pre-clinical models is inevitable. Starting from our recently published systematic review concerning the impact of muscarinic antagonists, we have systematically assessed the current pharmacological models of airway inflammation and provided an overview on the advances in in vitro and ex vivo approaches. The purpose of in vitro models is to recapitulate selected pathophysiological parameters or processes that are crucial to the development of new drugs within a controlled environment. Nevertheless, immortalized cell lines or primary airway cells present major limitations, including the inability to fully replicate the conditions of the corresponding cell types within a whole organism.

Induced animal models are extensively used in research in the attempt to replicate a respiratory condition reflective of a human pathological state, although considering animal models with spontaneously occurring respiratory diseases may be more appropriate since most of the clinical features are accompanied by lung pathology resembling that of the human condition.

In recent years, three-dimensional organoids have become an alternative to animal experiments, also because animal models are unable to fully mimic the complexity of human pulmonary diseases. Ex vivo studies performed on human isolated airways have a superior translational value compared to in vitro and animal models, as they retain the morphology and the microenvironment of the lung in vivo.

In the foreseeable future, greater effort should be undertaken to rely on more physiologically relevant models, that provide translational value into clinic and have a direct impact on patient outcomes.

Inflammatory and contractile profile in LPS-challenged equine isolated bronchi: Evidence for IL-6 as a potential target against AHR in equine asthma

BACKGROUND

Airway inflammation and airway hyperresponsiveness (AHR) are pivotal characteristics of equine asthma. Lipopolysaccharide (LPS) may have a central role in modulating airway inflammation and dysfunction. Therefore, the aim of this study was to match the inflammatory and contractile profile in LPS-challenged equine isolated bronchi to identify molecular targets potentially suitable to counteract AHR in asthmatic horses.

METHODS

Equine isolated bronchi were incubated overnight with LPS (0.1-100 ng/ml). The contractile response to electrical field stimulation (EFS) and the levels of cytokines, chemokines, and neurokinin A (NKA) were quantified. The role of capsaicin sensitive-sensory nerves, neurokinin-2 (NK₂) receptor, transient receptor potential vanilloid type 1 receptors (TRPV1), and epithelium were also investigated.

RESULTS

LPS 1 ng/ml elicited AHR to EFS (+238.17 ± 25.20% P < 0.001 vs. control). LPS significantly (P < 0.05 vs. control) increased the levels of IL-4 (+36.08 ± 1.62%), IL-5 (+38.60 ± 3.58%), IL-6 (+33.79 ± 2.59%), IL-13 (+40.91 ± 1.93%), IL-1β (+1650.16 ± 71.16%), IL-33 (+88.14 ± 8.93%), TGF-β (22.29 ± 1.03%), TNF-α (+56.13 ± 4.61%), CXCL-8 (+98.49 ± 17.70%), EOTAXIN (+32.26 ± 2.27%), MCP-1 (+49.63 ± 4.59%), RANTES (+36.38 ± 2.24%), and NKA (+112.81 ± 6.42%). Capsaicin sensitive-sensory nerves, NK₂ receptor, and TRPV1 were generally involved in the LPS-mediated inflammation. Epithelium removal modulated the release of IL-1β, IL-33, and TGF-β. Only the levels of IL-6 fitted with AHR to a wide range of EFS frequencies, an effect significantly (P < 0.05) inhibited by anti-IL-6 antibody; exogenous IL-6 induced significant (P < 0.05) AHR to EFS similar to that elicited by LPS.

CONCLUSION

Targeting IL-6 with specific antibody may represent an effective strategy to treat equine asthma, especially in those animals suffering from severe forms of this disease.

The role of long-acting muscarinic antagonist/long-acting β agonist fixed-dose combination treatment for chronic obstructive pulmonary disease in China: a narrative review

Objective

To provide an overview of the existing international and Chinese evidence regarding dual bronchodilator inhalation therapy and to make recommendations for the further improvement of chronic obstructive pulmonary disease (COPD) management in clinical practice in China.

Background

COPD is a progressive lung disease that is characterized by persistent airflow limitation and is a major contributor to the disease burden in China. Symptoms in Chinese patients are relatively more severe. Currently, many Chinese COPD patients are undertreated. Dual bronchodilator therapy consisting of a long-acting muscarinic antagonist (LAMA) and a long-acting β agonist (LABA) is considered a good choice for COPD patients due to the increased bronchodilation without an increase in adverse events; these combinations can fill in the gap in currently available COPD treatments and provide new pharmacotherapy options for Chinese patients. LAMA/LABA fixed-dose combinations (FDCs) have become more important in clinical practice and guidelines in China regarding their therapeutic effects and safety.

Methods

Clinical trials on LAMA/LABA in COPD were retrieved in ClinicalTrials.gov, while important COPD guidelines published in English or Chinese were found in PubMed and Wanfang Database.

Conclusions

We recommend the adoption of a clinical pathway in China that includes an assessment and management algorithm that considers the clinical characteristics in China and classifies the phenotypic characteristics of COPD according to a suitable system. Based on the current information, we can conclude that LAMA/LABA FDCs are a suitable and economically viable choice to reduce symptoms and improve the quality of life (QoL) of patients.

Drug interaction and chronic obstructive respiratory disorders

Chronic obstructive respiratory disorders uncontrolled by monotherapy should be given combinations of drugs that act by distinct mechanisms of action. The rationale for combining different classes of drugs should be to elicit a synergistic interaction, lower the dose of the single components in the combinations and, thus, reduce the risk of adverse events.

The aim of this systematic review was to investigate the combined effect of drugs acting on human airways, by including studies that used a validated method for assessing the nature of drug interaction.

Current evidence indicates that drug combinations modulating the bronchial contractility induce a synergistic relaxant effect when the individual components are combined at isoeffective concentrations. There are several mechanisms of action underlying drug interactions. Pharmacological research has been directed to elucidate what causes the synergism between long-acting β₂-adrenoceptor (β₂-AR) agonists (LABAs), long-acting muscarinic antagonist (LAMAs), and inhaled corticosteroids (ICS) administered as dual or triple combination. Conversely, the mechanisms behind the additive interaction between phosphodiesterase 3 and 4 inhibitors and LAMAs, and the synergistic interaction between proliferator-activated receptor gamma ligands and β₂ agonists have been only hypothesized. Overall, the synergism elicited by combined drugs for the treatment of chronic respiratory disorders is an effect of class, rather than specific for drug combinations. Optimal synergy can be achieved only when the single agents are combined at isoeffective concentrations, and when monocomponents are given concurrently to reach together the same levels of the bronchial tree.

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Drug interaction should be identified with validated pharmacological models.

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Synergistic efficacy is the rationale for combining drugs for respiratory diseases.

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Synergy is favored when combined agents act by distinct mechanisms of action.

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Optimal synergy is achieved when drugs are combined at isoeffective concentrations.

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Synergy is a class effect and is not specific for single drug combinations.

Rationale and Clinical Use of Bronchodilators in Adults with Bronchiectasis

Currently, there is much controversy surrounding the therapeutic approach to pulmonary function abnormalities in patients with bronchiectasis and, consequently, whether and when to use bronchodilators in these patients. National and international guidelines on the treatment of bronchiectasis in adults do not recommend the routine use of bronchodilators because there is no evidence that a significant response to a bronchodilator or the presence or hyperresponsiveness of the airway are good predictors of future effective clinical response. However, some guidelines recommend them in the presence of airway obstruction and/or special conditions, which vary according to the guideline in question, although there are no recommendations on optimal dosing and bronchodilator treatment combined with or without inhaled corticosteroids. Nonetheless, in contrast with guideline recommendations, bronchodilators are overused in real-world patients with bronchiectasis even in the absence of airway obstruction, as demonstrated by analysis of national and international registries. This overuse can be explained by the awareness of the existence of a solid pharmacological rationale that supports the use of bronchodilators in the presence of chronic airway obstruction independent of its aetiology. We performed a systematic review of the literature and were able to verify that there are no randomised controlled trials (apart from a small study with methodological limitations and a very recent trial involving a not-very-large number of patients), or any long-term observational studies on the short- or long-term effect of bronchodilators in patients with bronchiectasis. Therefore, we believe that it is essential and even urgent to evaluate the effects of bronchodilators in these patients with appropriately designed studies.

Impact of long-acting muscarinic antagonists on small airways in asthma and COPD: A systematic review

Small airway disease is recognized as a cardinal pathological process of chronic obstructive pulmonary disease (COPD), and recently small airways have been recognized as a major site of airflow obstruction also in asthmatic patients. The transversal involvement of small airways in COPD and asthma has warranted research efforts to identify therapeutic strategies able to unlock the small airway compartment. The mainstay of COPD treatment is represented by long-acting β₂-adrenoceptor agonists (LABAs) and long-acting muscarinic antagonists (LAMAs). In asthma, the efficacy of LAMAs administered add-on to inhaled corticosteroids (ICSs) or ICS/LABA combinations has been investigated only in recent years. The aim of this systematic review was to examine the current literature concerning the impact of LAMAs on small airways and their lung deposition in both COPD and asthma. LAMAs administered either alone or in combination induced an effective bronchorelaxant effect of small airways, however the effectiveness of respiratory medications not only relies on the selected drug, but also on the employed inhalation device and patient's adherence. Tiotropium delivered via Respimat® SMI achieved a superior drug deposition in the peripheral lung compared to HandiHaler® dry powder inhaler and metered-dose inhalers (MDIs). The use of co-suspension™ delivery technology for MDIs and the introduction of the eFlow® nebulizer to deliver glycopyrronium improved aerosol drug delivery to the peripheral lung, by achieving uniform distribution of drug particles. This systematic review provides a synthesis of current literature concerning the impact of LAMAs on small airways and an insight on LAMAs distribution within the lung.

The Impact of Monoclonal Antibodies on Airway Smooth Muscle Contractility in Asthma: A Systematic Review

Airway hyperresponsiveness (AHR) represents a central pathophysiological hallmark of asthma, with airway smooth muscle (ASM) being the effector tissue implicated in the onset of AHR. ASM also exerts pro-inflammatory and immunomodulatory actions, by secreting a wide range of cytokines and chemokines. In asthma pathogenesis, the overexpression of several type 2 inflammatory mediators including IgE, IL-4, IL-5, IL-13, and TSLP has been associated with ASM hyperreactivity, all of which can be targeted by humanized monoclonal antibodies (mAbs). Therefore, the aim of this review was to systematically assess evidence across the literature on mAbs for the treatment of asthma with respect to their impact on the ASM contractile tone. Omalizumab, mepolizumab, benralizumab, dupilumab, and tezepelumab were found to be effective in modulating the contractility of the ASM and preventing the AHR, but no available studies concerning the impact of reslizumab on the ASM were identified from the literature search. Omalizumab, dupilumab, and tezepelumab can directly modulate the ASM in asthma, by specifically blocking the interaction between IgE, IL-4, and TSLP, and their receptors are located on the surface of ASM cells. Conversely, mepolizumab and benralizumab have prevalently indirect impacts against AHR by targeting eosinophils and other immunomodulatory effector cells promoting inflammatory processes. AHR has been suggested as the main treatable trait towards precision medicine in patients suffering from eosinophilic asthma, therefore, well-designed head-to-head trials are needed to compare the efficacy of those mAbs that directly target ASM contractility specifically against the AHR in severe asthma, namely omalizumab, dupilumab, and tezepelumab.

Indacaterol, glycopyrronium, and mometasone: pharmacological interaction and anti-inflammatory profile in hyperresponsive airways

LABA/ICS and LABA/LAMA/ICS combinations elicit beneficial effects in asthma. Specific evidence concerning the impact of combining indacaterol acetate (IND), glycopyrronium bromide (GLY), and mometasone furoate (MF) on human airway hyperresponsiveness (AHR) and airway inflammation is still missing. The aim of this study was to characterize the synergy of IND/MF and IND/GLY/MF combinations, both once-daily treatments for asthma, in hyperresponsive airways. Passively sensitized human medium and small airways were stimulated by histamine and treated with IND/MF (molar ratio: 100/45, 100/90) and IND/GLY/MF (molar ratio: 100/37/45, 100/37/90). The effect on contractility and airway inflammation was tested. Drug interaction was assessed by Bliss Independence equation and Unified Theory. IND/MF 100/90 elicited middle-to-very strong synergistic relaxation in medium and small airways (+≈20-30% vs. additive effect, P<0.05), for IND/MF 100/45 the synergy was middle-to-very strong in small airways (+≈20% vs. additive effect, P<0.05), and additive in medium bronchi (P>0.05 vs. additive effect). IND/GLY/MF 100/37/45 and 100/37/90 induced very strong synergistic relaxation in medium and small airways (+≈30-50% vs. additive effect, P<0.05). Synergy was related with significant (P<0.05) reduction in IL-4, IL-5, IL-6, IL-9, IL-13, TNF-α, TSLP, NKA, SP, and non-neuronal ACh, and enhancement in cAMP. IND/MF and IND/GLY/MF combinations synergistically interact in hyperresponsive medium and small airways and modulate the levels of cytokines, neurokinins, ACh, and intracellular cAMP. The concentrations of MF in the combinations modulate the effects in the target tissue.

Long-acting muscarinic antagonists and small airways in asthma: Which link?

Involvement of small airways, those of <2 mm in internal diameter, is present in all stages of asthma and contributes substantially to its pathophysiologic expression. Therefore, small airways are a potential target to achieve optimal asthma control. Airway tone, which is increased in asthma, is mainly controlled by the vagus nerve that releases acetylcholine (ACh) and activates muscarinic ACh receptors (mAChRs) post-synaptically on airway smooth muscle (ASM). In small airways, M₃ mAChRs are expressed, but there is no vagal innervation. Non-neuronal ACh released from the epithelial cells that may express choline acetyltransferase in response to inflammatory stimuli, as well as from other structural cells in the airways, including fibroblasts and mast cells, can activate mAChRs. By antagonizing M₃ mAChR, the contraction of the ASM is prevented and, potentially, local inflammation can be reduced and the progression of remodeling may be averted. In fact, ACh also contributes to inflammation and remodeling of the airways and regulates the growth of ASM. Several experimental studies have demonstrated the potential benefit derived from the use of mAChR antagonists, mainly long-acting mAChR antagonists (LAMAs), on small airways in asthma. However, there are several confounding factors that may cause a wrong estimation of the relationship between LAMAs and small airways in asthma. Further studies are needed to differentiate broncholytic and anti-inflammatory effects of LAMAs and to better understand the interaction between LAMAs and corticosteroids, also in the context of a triple therapy that includes a β₂ -AR agonist, at different levels of the bronchial tree.

Effects of indacaterol on the LPS-evoked changes in fluid secretion rate and pH in swine tracheal membrane

An acquired dysregulation of airway secretion is likely involved in the pathophysiology of chronic bronchitis and chronic obstructive pulmonary disease (COPD). Nowadays, it is widely known that several kinds of long-acting bronchodilators reduce the frequency of COPD exacerbations. However, limited data are available concerning the complementary additive effects on airflow obstruction. Using an optical method and a selective pH indicator, we succeeded in evaluating the gland secretion rate and the pH in swine tracheal membrane. A physiologically relevant concentration of acetylcholine (ACh) 100 nM induced a gradual increase in the amount of gland secretion. Lipopolysaccharides (LPS) accelerated the ACh-induced secretory responses up to around threefold and lowered the pH level significantly. Long-acting β₂-agonists (LABAs) including indacaterol (IND), formoterol, and salmeterol restored the LPS-induced changes in both the hypersecretion and acidification. The subsequent addition of the long-acting muscarine antagonist, glycopyrronium, further increased the pH values. Two different inhibitors for cystic fibrosis transmembrane conductance regulator (CFTR), NPPB and CFTR_inh172, abolished the IND-mediated pH normalization in the presence of both ACh and ACh + LPS. Both immunofluorescence staining and western blotting analysis revealed that LPS downregulated the abundant expression of CFTR protein. However, IND did not restore the LPS-induced decrease in CFTR expression on Calu-3 cells. These findings suggest that the activation of cAMP-dependent HCO₃⁻ secretion through CFTR would be partly involved in the IND-mediated pH normalization in gland secretion and may be suitable for the maintenance of airway defense against exacerbating factors including LPS.

Inhaled long-acting muscarinic antagonists in asthma - A narrative review

Long-acting muscarinic antagonists (LAMAs) have a recognised role in the management of chronic obstructive pulmonary disease. In asthma, muscarinic antagonists (both short- and long-acting) were historically considered less effective than β₂-agonists; only relatively recently have studies been conducted to evaluate the efficacy of LAMAs, as add-on to either inhaled corticosteroid (ICS) monotherapy or ICS/long-acting β₂-agonist (LABA) combinations. These studies led to the approval of the first LAMA, tiotropium, as an add-on therapy in patients with poorly controlled asthma. Subsequently, a number of single-inhaler ICS/LABA/LAMA triple therapies have been approved or are in clinical development for the management of asthma. There is now substantial evidence of the efficacy and safety of LAMAs in asthma that is uncontrolled despite treatment with an ICS/LABA combination. This regimen is recommended by GINA as an optimisation step for patients with severe asthma before any biologic or systemic corticosteroid treatment is initiated. This narrative review summarises the potential mechanisms of action of LAMAs in asthma, together with the initial clinical evidence supporting this use. We also discuss the studies that led to the approval of tiotropium for asthma and the data evaluating the efficacy and safety of the various triple therapies, before considering other potential uses for triple therapy.

Comparative studies of dual bronchodilation in COPD

Dual bronchodilation therapy is becoming the cornerstone for the treatment of COPD because the clinical benefits of LABA/LAMA fixed-dose combinations (FDCs) are now extensively established. Therefore, it not surprising that a number of LAMA/LABA combinations in a single inhaler have now been approved for clinical use as treatments for patients with COPD. Regrettably, very few head-to-head studies between all of the available LABA/LAMA FDCs have been carried out. This makes choosing the most appropriate FDC difficult. Comparative effectiveness research that also uses conventional meta-analyses to compare different care strategies can help generate useful information. A bidimensional comparative analysis across LAMA/LABA FDCs has suggested constant superiority for tiotropium/olodaterol. However, considering that there is not an equivalent amount of evidence on efficacy outcomes for all LAMA/LABA FDCs, a proper comparison between the different LAMA/LABA FDCs cannot be made yet, and the information available is still rather inconsistent.

The Impact of Muscarinic Receptor Antagonists on Airway Inflammation: A Systematic Review

Long-acting muscarinic receptor antagonists (LAMAs) are the cornerstone for the treatment of chronic obstructive pulmonary disease (COPD); furthermore, tiotropium is approved as add-on therapy in severe asthmatic patients. Accumulating evidence suggests that LAMAs may modulate airway contractility and airway hyperresponsiveness not only by blocking muscarinic acetylcholine receptors (mAchRs) expressed on airway smooth muscle but also via anti-inflammatory mechanisms by blocking mAchRs expressed on inflammatory cells, submucosal glands, and epithelial cells. The aim of this systematic review, performed according to the PRISMA-P guidelines, was to provide a synthesis of the literature on the anti-inflammatory impact of muscarinic receptor antagonists in the airways. Most of the current evidence originates from studies on tiotropium, that demonstrated a reduction in synthesis and release of cytokines and chemokines, as well as the number of total and differential inflammatory cells, induced by different pro-inflammatory stimuli. Conversely, few data are currently available for aclidinium and glycopyrronium, whereas no studies on the potential anti-inflammatory effect of umeclidinium have been reported. Overall, a large body of evidence supports the beneficial impact of tiotropium against airway inflammation. Further well-designed randomized controlled trials are needed to better elucidate the anti-inflammatory mechanisms leading to the protective effect of LAMAs against exacerbations via identifying suitable biomarkers.

A randomized controlled trial of long-acting muscarinic antagonist and long-acting β2 agonist fixed-dose combinations in patients with chronic obstructive pulmonary disease

Background

In chronic obstructive pulmonary disease (COPD) patients, combination treatment with long-acting muscarinic antagonist (LAMA) and long-acting β2 agonist (LABA) increases forced expiratory volume in one second and reduces symptoms compared to monotherapy. In Japan, three different once-daily fixed-dose combinations (FDCs) have been prescribed since 2015, although a direct comparison of these FDCs has never been performed. The objective of the present study was to compare the effectiveness, preference, and safety of three LAMA/LABA FDCs—glycopyrronium/indacaterol (Gly/Ind), umeclidinium/vilanterol (Ume/Vil), and tiotropium/olodaterol (Tio/Olo)—in patients with COPD.

Methods

We enrolled 75 COPD outpatients (male:female ratio, 69:6; 77.4 ± 6.9 years). A prospective, randomized, crossover study was conducted on three groups using three FDCs: Gly/Ind; Ume/Vil; and Tio/Olo. Each medication was administered for 4 weeks before crossover (total 12 weeks). After each FDC administration, a respiratory function test and questionnaire survey were conducted. A comparative questionnaire survey of all three LAMA/LABA FDCs was conducted after 12 weeks (following administration of final FDC).

Results

No significant differences in COPD Assessment Test or modified Medical Research Council dyspnea questionnaire were reported in the surveys completed after each FDC administration; no significant differences in spirometric items were observed. In the final comparative questionnaire survey, patients reported better actual feeling of being able to inhale following Gly/Ind administration compared with Tio/Olo, although no significant differences in adverse events or other evaluations were reported.

Conclusions

The three LAMA/LABA FDCs administered to COPD patients show similar effects and safety, although some minor individual preference was reported.

Trial registration This study retrospectively registered with the University Hospital Medical Information Network Clinical Trials Registry (number UMIN000041342, registered on August 6, 2020).

Ultra Long-Acting β-Agonists in Chronic Obstructive Pulmonary Disease

INTRODUCTION

Inhaled β-agonists have been foundational medications for maintenance COPD management for decades. Through activation of cyclic adenosine monophosphate pathways, these agents relax airway smooth muscle and improve expiratory airflow by relieving bronchospasm and alleviating air trapping and dynamic hyperinflation improving breathlessness, exertional capabilities, and quality of life. β-agonist drug development has discovered drugs with increasing longer durations of action: short acting (SABA) (4-6 h), long acting (LABA) (6-12 h), and ultra-long acting (ULABA) (24 h). Three ULABAs, indacaterol, olodaterol, and vilanterol, are approved for clinical treatment of COPD.

PURPOSE

This article reviews both clinically approved ULABAs and ULABAs in development.

CONCLUSION

Indacaterol and olodaterol were originally approved for clinical use as monotherapies for COPD. Vilanterol is the first ULABA to be approved only in combination with other respiratory medications. Although there are many other ULABA's in various stages of development, most clinical testing of these novel agents is suspended or proceeding slowly. The three approved ULABAs are being combined with antimuscarinic agents and corticosteroids as dual and triple agent treatments that are being tested for clinical use and efficacy. Increasingly, these clinical trials are using specific COPD clinical characteristics to define study populations and to begin to develop therapies that are trait-specific.

Comparisons of exacerbations and mortality among LAMA/LABA combinations in stable chronic obstructive pulmonary disease: systematic review and Bayesian network meta-analysis

BACKGROUND

Only few randomized controlled trials (RCTs) for head-to-head comparison have been conducted between various combinations of long-acting muscarinic antagonists (LAMAs) and long-acting beta-agonists (LABAs). Our study was conducted to compare acute exacerbation and all-cause mortality among different LAMA/LABA regimens using Bayesian network meta-analysis (NMA).

METHODS

We searched Medline, EMBASE, and the Cochrane library (search date: July 1, 2019). We included parallel-group RCTs comparing LAMA/LABA combinations with other inhaled drugs in the stable COPD for ≥ 48 weeks. Two different network geometries were used. The geometry of network (A) had nodes of individual drugs or their combination, while that of network (B) combined all other treatments except LAMA/LABA into each drug class. This study was prospectively registered in PROSPERO; CRD42019126753.

RESULTS

We included 16 RCTs involving a total of 39,065 patients with stable COPD. Six combinations of LAMA/LABA were identified: tiotropium/salmeterol, glycopyrrolate/indacaterol, umeclidinium/vilanterol, tiotropium/olodaterol, aclidinium/formoterol, and glycopyrrolate/formoterol. We found that umeclidinium/vilanterol was associated with a lower risk of total exacerbations than other LAMA/LABAs in the NMA using network (A) (level of evidence: low or moderate). However, the significant differences were not present in the NMA of network (B). There were no significant differences among the LAMA/LABA combinations in terms of the number of moderate to severe exacerbations, all-cause mortality, major adverse cardiovascular events, or pneumonia.

CONCLUSIONS

The present NMA including all available RCTs provided that there is no strong evidence suggesting different benefits among LAMA/LABAs in patients with stable COPD who have been followed up for 48 weeks or more.

TRIAL REGISTRATION

This study was prospectively registered in PROSPERO; CRD42019126753.

Pharmacology and Therapeutics of Bronchodilators Revisited

Bronchodilators remain the cornerstone of the treatment of airway disorders such as asthma and chronic obstructive pulmonary disease (COPD). There is therefore considerable interest in understanding how to optimize the use of our existing classes of bronchodilator and in identifying novel classes of bronchodilator drugs. However, new classes of bronchodilator have proved challenging to develop because many of these have no better efficacy than existing classes of bronchodilator and often have unacceptable safety profiles. Recent research has shown that optimization of bronchodilation occurs when both arms of the autonomic nervous system are affected through antagonism of muscarinic receptors to reduce the influence of parasympathetic innervation of the lung and through stimulation of β ₂-adrenoceptors (β ₂-ARs) on airway smooth muscle with β ₂-AR-selective agonists to mimic the sympathetic influence on the lung. This is currently achieved by use of fixed-dose combinations of inhaled long-acting β ₂-adrenoceptor agonists (LABAs) and long-acting muscarinic acetylcholine receptor antagonists (LAMAs). Due to the distinct mechanisms of action of LAMAs and LABAs, the additive/synergistic effects of using these drug classes together has been extensively investigated. More recently, so-called "triple inhalers" containing fixed-dose combinations of both classes of bronchodilator (dual bronchodilation) and an inhaled corticosteroid in the same inhaler have been developed. Furthermore, a number of so-called "bifunctional drugs" having two different primary pharmacological actions in the same molecule are under development. This review discusses recent advancements in knowledge on bronchodilators and bifunctional drugs for the treatment of asthma and COPD. SIGNIFICANCE STATEMENT: Since our last review in 2012, there has been considerable research to identify novel classes of bronchodilator drugs, to further understand how to optimize the use of the existing classes of bronchodilator, and to better understand the role of bifunctional drugs in the treatment of asthma and chronic obstructive pulmonary disease.

Targeting IL-5 pathway against airway hyperresponsiveness: A comparison between benralizumab and mepolizumab

BACKGROUND AND PURPOSE

Airway hyperresponsiveness (AHR) is a central abnormality in asthma. IL-5 may modulate AHR in animal models of asthma, but the available data is inconsistent on the impact of targeting IL-5 pathway against AHR. The difference between targeting IL-5 or the IL-5 receptor, α subunit (IL-5Rα) in modulating AHR remains to be investigated in human airways. The aim of this study was to compare the role of the anti-IL-5Rα benralizumab and the anti-IL-5 mepolizumab against AHR and to assess whether these agents influence the levels of cAMP.

EXPERIMENTAL APPROACH

Passively sensitized human airways were treated with benralizumab and mepolizumab. The primary endpoint was the inhibition of AHR to histamine. The secondary endpoints were the protective effect against AHR to parasympathetic activation and mechanical stress, and the tissue modulation of cAMP.

KEY RESULTS

Benralizumab and mepolizumab significantly inhibited the AHR to histamine (maximal effect -134.14 ± 14.93% and -108.29 ± 32.16%, respectively), with benralizumab being 0.73 ± 0.10 logarithm significantly more potent than mepolizumab. Benralizumab and mepolizumab significantly inhibited the AHR to transmural stimulation and mechanical stress. Benralizumab was 0.45 ± 0.16 logarithm significantly more potent than mepolizumab against AHR to parasympathetic activation. The effect of these agents was significantly correlated with increased levels of cAMP.

CONCLUSION AND IMPLICATIONS

Targeting the IL-5/IL-5Rα axis is an effective strategy to prevent the AHR. Benralizumab was more potent than the mepolizumab and the concentration-dependent beneficial effects of both these monoclonal antibodies were related to improved levels of cAMP in hyperresponsive airways.

Cholinergic receptors on intestine cells of Ascaris suum and activation of nAChRs by levamisole

Cholinergic agonists, like levamisole, are a major class of anthelmintic drugs that are known to act selectively on nicotinic acetylcholine receptors (nAChRs) on the somatic muscle and nerves of nematode parasites to produce their contraction and spastic paralysis. Previous studies have suggested that in addition to the nAChRs found on muscle and nerves, there are nAChRs on non-excitable tissues of nematode parasites. We looked for evidence of nAChRs expression in the cells of the intestine of the large pig nematode, Ascaris suum, using RT-PCR and RNAscope in situ hybridization and detected mRNA of nAChR subunits in the cells. These subunits include components of the putative levamisole receptor in A. suum muscle: Asu-unc-38, Asu-unc-29, Asu-unc-63 and Asu-acr-8. Relative expression of these mRNAs in A. suum intestine was quantified by qPCR. We also looked for and found expression of G protein-linked acetylcholine receptors (Asu-gar-1). We used Fluo-3 AM to detect intracellular calcium changes in response to receptor activation by acetylcholine (as a non-selective agonist) and levamisole (as an L-type nAChR agonist) to look for evidence of functioning nAChRs in the intestine. We found that both acetylcholine and levamisole elicited increases in intracellular calcium but their signal profiles in isolated intestinal tissues were different, suggesting activation of different receptor sets. The levamisole responses were blocked by mecamylamine, a nicotinic receptor antagonist in A. suum, indicating the activation of intestinal nAChRs rather than G protein-linked acetylcholine receptors (GARs) by levamisole. The detection of nAChRs in cells of the intestine, in addition to those on muscles and nerves, reveals another site of action of the cholinergic anthelmintics and a site that may contribute to the synergistic interactions of cholinergic anthelmintics with other anthelmintics that affect the intestine (Cry5B).

The reality of LAMAs for adult asthmatic patients

INTRODUCTION

The use of tiotropium is approved for the treatment of asthma. There are several studies completed or currently ongoing with the long-acting muscarinic antagonists (LAMAs) umeclidinium and glycopyrronium as an add-on asthma treatment. Adding a second bronchodilator with a different mechanism of action for the treatment of uncontrolled asthma may be a suitable therapeutic approach, although several issues still under discussion.

AREAS COVERED

The reality of LAMA plus long-acting beta-agonists (LABA) treatment for adult asthma. A systematic search was conducted on March 2020, and included 6 electronic databases: EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science and Google Scholar.

EXPERT OPINION

A growing body of evidence generated from several randomized clinical trials is supporting the use of LAMA in adulthood asthma always in association with inhaled corticosteroid (ICS). Currently, only tiotropium has been approved and included in the guidelines. Other LAMAs are under evaluation in clinical trials. Several clinical trials are supporting the use of a triple therapy (ICS/LABA/LAMA) in uncontrolled asthmatic patients under ICS/LABA.

Day and Night Control of COPD and Role of Pharmacotherapy: A Review

The topic of 24-hour management of COPD is related to day-to-night symptoms management, specific follow-up and patients' adherence to therapy. COPD symptoms strongly vary during day and night, being worse in the night and early morning. This variability is not always adequately considered in the trials. Night-time symptoms are predictive of higher mortality and more frequent exacerbations; therefore, they should be a target of therapy. During night-time, in COPD patients the supine position is responsible for a different thoracic physiology; moreover, during some sleep phases the vagal stimulation determines increased bronchial secretions, increased blood flow in the bronchial circulation (enhancing inflammation) and increased airway resistance (broncho-motor tone). Moreover, in COPD patients the circadian rhythm may be impaired. The role of pharmacotherapy in this regard is still poorly investigated. Symptoms can be grossly differentiated according to the different phenotypes of the disease: wheezing recalls asthma, while dyspnea is strongly related to emphysema (dynamic hyperinflation) or obstructive bronchiolitis (secretions). Those symptoms may be different targets of therapy. In this regard, GOLD recommendations for the first time introduced the concept of phenotype distinction suggesting the use of inhaled corticosteroids (ICS) particularly when an asthmatic pattern or eosiophilic inflammations are present, and hypothesized different approaches to target symptoms (ie, dyspnea) or exacerbations. Pharmacotherapy should be evaluated and possibly directed on the basis of circadian variations, for instance, supporting the use of twice-daily rapid-action bronchodilators and evening dose of ICS. Recommendations on day and night symptoms monitoring strategies and choice of the specific drug according to patient's profile are still not systematically investigated or established. This review is the summary of an advisory board on the topic "24-hour control of COPD and role of pharmacotherapy", held by five pulmonologists, experts in respiratory pathophysiology, pharmacology and sleep medicine.

New perspectives on the role of muscarinic antagonists in asthma therapy

INTRODUCTION

There is increasing evidence that tiotropium, a long-acting muscarinic agent (LAMA), is useful in the presence of severe-uncontrolled asthma despite the optimization of therapy with inhaled corticosteroids (ICSs) and long-acting β₂ agonists (LABAs) as recommended by the current guidelines. Furthermore, in recent years there have been several  preclinical and clinical studies on the pharmacological and therapeutic impact of other LAMAs in asthma.

AREAS COVERED

We have conducted an extensive search on muscarinic antagonists in asthma therapy throughout several sources and discuss what has emerged in the last 3 years (January 2017-March 2020).

EXPERT OPINION

New evidence indicates that the effectiveness of adding a LAMA, at least tiotropium, is independent of the degree of the type 2 inflammation and age of patient. Therefore, tiotropium can be administered without the need for patient phenotyping. Umeclidinium and glycopyrronium also appear effective in asthma. Initial treatment with LAMA+ICS for those with mild asthma may be an equally effective therapeutic option as LABA+ICS but this hypothesis should be confirmed by statistically powered trials.

Optimizing the Development Strategy of Combination Therapy in Respiratory Medicine: From Isolated Airways to Patients

The current recommendations for the treatment of chronic obstructive pulmonary disease (COPD) are pushing towards triple combination therapy based on the combination of an inhaled corticosteroid (ICS) associated with two bronchodilator agents. However, dual bronchodilation remains the cornerstone for the treatment of most COPD patients. Combining a long-acting β₂ adrenoceptor agonist (LABA) with a long-acting muscarinic antagonist (LAMA) induces appreciable synergistic bronchorelaxant effect in human airways, especially when the medications are combined at isoeffective concentrations. Thus, each LABA/LAMA combination is characterized by a specific range of concentration-ratio at which the drug mixture may induce sustained synergistic interaction. Results of a recent randomized controlled trial (RCT, NCT00696020) and evidences from pre-clinical studies in human isolated airways poses the question whether combining tiotropium 5 μg with olodaterol 5 μg is the best combination option: tiotropium/olodaterol 5/5 μg has the same efficacy profile of tiotropium/olodaterol 5/2 μg, and it is less effective than tiotropium/olodaterol 5/10 μg. Furthermore, tiotropium/olodaterol 5/2 μg, 5/5 μg, and 5/10 μg combinations are generally characterized by the same safety profile. Indeed tiotropium/olodaterol 5/5 μg is effective and safe in COPD, but a different development strategy based on solid data obtained from human isolated airways would have driven towards a better-balanced FDC to be tested in Phase III RCTs. Accurate bench-to-bedside plans are needed also in the development of triple combination therapies for asthma and COPD, in which the presence of an ICS in the formulation may further modulate the beneficial interaction between the LABA and the LAMA.

The Airways' Mechanical Stress in Lung Disease: Implications for COPD Pathophysiology and Treatment Evaluation

The airway epithelium stretches and relaxes during the normal respiratory cycle, and hyperventilation exaggerates this effect, resulting in changes in lung physiology. In fact, stretching of the airways influences lung function and the secretion of airway mediators, which in turn may cause a potentially injurious inflammatory response. This aim of the present narrative review was to illustrate the current evidence on the importance of mechanical stress in the pathophysiology of lung diseases with a particular focus on chronic obstructive pulmonary disease (COPD) and to discuss how this may influence pharmacological treatment strategies. Overall, treatment selection should be tailored to counterpart the effects of mechanical stress, which influences inflammation both in asthma and COPD. The most suitable treatment approach between a long-acting β2-agonists/long-acting antimuscarinic-agonist (LABA/LAMA) alone or with the addition of inhaled corticosteroids should be determined based on the underlying mechanism of inflammation. Noteworthy, the anti-inflammatory effects of the glycopyrronium/indacaterol combination on hyperinflation and mucociliary clearance may decrease the rate of COPD exacerbations, and it may synergistically improve bronchodilation with a double action on both the cyclic adenosine monophosphate (cAMP) and the acetylcholine pathways.

A potential role of triple therapy for asthma patients

Introduction: The use of LAMAs in asthma is now supported by pharmacological and clinical evidence, whereas the effectiveness of therapy with ICS/LABA/LAMA fixed dose combinations in patients with asthma still remains to be determined. Areas covered: The pharmacological rationale that explains why it is possible to use triple therapy in asthma and the results of clinical studies that have explored the effects of this therapy in asthmatics is critically examined. A systematic search was conducted on 10 August 2019, and included six electronic databases: EMBASE, MEDLINE, Scopus, The Cochrane Library, Web of Science, and Google Scholar. Expert opinion: The real role of single inhaler triple therapy in asthma will be demonstrated when the various trials that are currently ongoing or are scheduled will be completed. We believe that it is appropriate to treat with triple therapy asthmatic patients who have smoked and remain symptomatic or suffer from frequent exacerbations despite initial inhaler therapy with ICS/LABA. However, we must establish when to step up or mainly step down triple therapy especially in patients who are well controlled, and what will be the cost of these combinations in the management of asthma.

Pharmacological treatment and current controversies in COPD

Bronchodilators, corticosteroids, and antibiotics are still key elements for treating chronic obstructive pulmonary disease in the 2019 Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendations and this is due in part to our current inability to discover new drugs capable of decisively influencing the course of the disease. However, in recent years, information has been produced that, if used correctly, can allow us to improve the use of the available therapies.

Long-term observational study on the impact of GLP-1R agonists on lung function in diabetic patients

INTRODUCTION

Preclinical research suggests a role of Glucagon Like Peptide-1 Receptors (GLP-1R) on the regulation of human bronchial tone. We investigated the effect of GLP-1R agonists on lung function of Type 2 Diabetes Mellitus (T2DM) population without co-existing chronic obstructive respiratory disorders.

METHODS

This was a prospective cohort study that examined change in lung function measurements over two years of T2DM patients (n = 32) treated with metformin monotherapy (control cohort), metformin plus GLP-1R agonists (GLP-1R agonists cohort), or metformin plus insulin (insulin cohort).

RESULTS

After 24 months of treatment, the forced expiratory volume in 1 s (FEV₁) significantly (p < 0.05) increased from baseline in the GLP-1R agonists cohort (218 ml [95%CI 88-246]), but not in the control and insulin cohorts (94 ml [95%CI -28 - 216] and 26 ml [95%CI -174 - 226], respectively; p > 0.05 vs. baseline). The average increase in FEV₁ in the GLP-1R agonists cohort was significantly greater than that in the control and insulin cohorts (delta: 110 ml [95%CI 18-202] and 177 ml [95%CI 85-270], respectively, p < 0.05). The forced vital capacity (FVC) also increased significantly more in the GLP-1R agonists cohort than in the control and insulin cohorts (overall delta FVC: 183 ml [95%CI 72-295], p < 0.05). The maximal expiratory flow at 50-75% significantly (p < 0.05) improved from baseline in the GLP-1R agonists cohort, but not in the control and insulin cohorts (p > 0.05).

CONCLUSION

Our preliminary results suggest a potential new therapeutic perspective to treat airway disorders with GLP-1R agonists.

The once-daily fixed-dose combination of olodaterol and tiotropium in the management of COPD: current evidence and future prospects

Long-acting bronchodilators are the cornerstone of pharmacologic treatment of chronic obstructive pulmonary disease (COPD). Spiolto® or Stiolto® is a fixed-dose combination (FDC) containing two long-acting bronchodilators, the long-acting muscarinic receptor antagonist tiotropium (TIO) and the long-acting β2-adrenoceptor agonist olodaterol (OLO), formulated in the Respimat® Soft Mist™ inhaler. A total of 13 large, multicentre studies of up to 52 weeks' duration have documented its efficacy in more than 15,000 patients with COPD. TIO/OLO 5/5 µg FDC significantly increases pulmonary function compared with placebo and its respective constituent mono-components TIO 5 µg and OLO 5 µg. TIO/OLO 5/5 µg also results in statistically and clinically significant improvements in patient-reported outcomes, such as dyspnoea, use of rescue medication, and health status. Addition of OLO 5 µg to TIO 5 µg reduces the rate of moderate-to-severe exacerbations by approximately 10%. Compared with placebo and TIO 5 µg, TIO/OLO 5/5 µg significantly improves exercise capacity (e.g. endurance time) and physical activity, the latter increase being reached by a unique combination behavioural modification intervention, dual bronchodilatation and exercise training. Overall, the likelihood for patients to experience a clinically significant benefit is higher with TIO/OLO 5/5 µg than with its constituent mono-components, which usually yield smaller improvements which do not always reach statistical significance, compared with baseline or placebo. This supports the early introduction of TIO/OLO 5/5 µg in the management of patients with symptomatic COPD.

The Cholinergic Pathways in Inflammation: A Potential Pharmacotherapeutic Target for COPD

In COPD, the activity of the cholinergic system is increased, which is one of the reasons for the airflow limitation caused by the contraction of airway smooth muscles. Therefore, blocking the contractive actions with anticholinergics is a useful therapeutic intervention to reduce the airflow limitation. In addition to the effects of bronchoconstriction and mucus secretion, accumulating evidence from animal models of COPD suggest acetylcholine has a role in inflammation. Experiments using muscarinic M₃-receptor deficient mice or M₃ selective antagonists revealed that M₃-receptors on parenchymal cells, but not on hematopoietic cells, are involved in the pro-inflammatory effect of acetylcholine. Recently, combinations of long-acting β2 adrenergic agonists (LABAs) and long-acting muscarinic antagonists (LAMAs) have become available for COPD treatment. These dual long-acting bronchodilators may have synergistic anti-inflammatory effects because stimulation of β2 adrenergic receptors induces inhibitory effects in inflammatory cells via a different signaling pathway from that by antagonizing M₃-receptor, though these anti-inflammatory effects have not been clearly demonstrated in COPD patients. In contrast to the pro-inflammatory effects by ACh via muscarinic receptors, it has been demonstrated that the cholinergic anti-inflammatory pathway, which involves the parasympathetic nervous systems, regulates excessive inflammatory responses to protect organs during tissue injury and infection. Stimulation of acetylcholine via the α7 nicotinic acetylcholine receptor (α7nAChR) exerts inhibitory effects on leukocytes including macrophages and type 2 innate lymphoid cells. Although it remains unclear whether the inhibitory effects of acetylcholine via α7nAChR in inflammatory cells can regulate inflammation in COPD, neuroimmune interactions including the cholinergic anti-inflammatory pathway might serve as potential therapeutic targets.

Effects of a single long-acting muscarinic antagonist agent and a long-acting muscarinic antagonist/long-acting β2-adrenoceptor agonist combination on lung function and symptoms in untreated COPD patients in Japan

BACKGROUND

A large body of evidence suggests that long-acting β2-adrenoceptor agonist (LABA)/long-acting muscarinic antagonist (LAMA) combinations induce a strong synergistic bronchodilatory effect in human isolated airways. Moreover, a recent post hoc analysis demonstrated clinical synergism between LABAs and LAMAs, which induces a synergistic improvement not only in lung function but also in dyspnea in COPD patients.

AIM

The aim of this study is to examine the baseline factors related to improvement in lung function or clinical symptoms that results from the administration of LAMA or LAMA/LABA and to compare the differences in improvement in lung function or clinical symptoms between LAMA and LAMA/LABA.

METHODS

Among 829 patients with COPD who were treated with LAMA or LAMA/LABA in our hospital, 112 patients (aged 40-89 years) matched the criteria. Of these 112 patients, 71 received LAMA (LAMA group) and 41 received LAMA/LABA (LAMA/LABA group) as the initial treatment. Various examination results such as lung function test values, symptom change, and frequency of exacerbations were compared between the two groups.

RESULTS

Compared with the monotherapy, the combination therapy significantly improved the FEV1, inspiratory capacity (IC), and total COPD assessment test (CAT) scores. Comparing the improvement in each domain of the CAT produced by the combination therapy with that of the monotherapy, larger improvements were found for the domains of going out and sleeping. The frequency of exacerbations during the 24 weeks was significantly lower in the combination therapy group than in the LAMA monotherapy group (P=0.034). Although no relationship was found between improvement in FEV1 and any pretreatment factors in the LAMA/LABA group, the improvement in the CAT score was strongly related to the baseline CAT score, smoking index, and air trapping index (P-value <1×10-4).

CONCLUSION

In this study of clinical practice, we found that LAMA/LABA combination therapy improved the clinical symptoms of COPD and IC and that the effects of the combination therapy were consistent with those observed in previous clinical trials.

Involvement of Allosteric Effect and KCa Channels in Crosstalk between β₂-Adrenergic and Muscarinic M₂ Receptors in Airway Smooth Muscle

To advance the development of bronchodilators for asthma and chronic obstructive pulmonary disease (COPD), this study was designed to investigate the mechanism of functional antagonism between β₂-adrenergic and muscarinic M₂ receptors, focusing on allosteric effects and G proteins/ion channels coupling. Muscarinic receptor antagonists (tiotropium, glycopyrronium, atropine) synergistically enhanced the relaxant effects of β₂-adrenergic receptor agonists (procaterol, salbutamol, formoterol) in guinea pig trachealis. This crosstalk was inhibited by iberitoxin, a large-conductance Ca²⁺-activated K⁺ (K_Ca) channel inhibitor, whereas it was increased by verapamil, a L-type voltage-dependent Ca²⁺ (VDC) channel inhibitor; additionally, it was enhanced after tissues were incubated with pertussis or cholera toxin. This synergism converges in the G proteins (G_i, G_s)/K_Ca channel/VDC channel linkages. Muscarinic receptor antagonists competitively suppressed, whereas, β₂-adrenergic receptor agonists noncompetitively suppressed muscarinic contraction. In concentration-inhibition curves for β₂-adrenergic receptor agonists with muscarinic receptor antagonists, EC₅₀ was markedly decreased, and maximal inhibition was markedly increased. Hence, muscarinic receptor antagonists do not bind to allosteric sites on muscarinic receptors. β₂-Adrenergic receptor agonists bind to allosteric sites on these receptors; their intrinsic efficacy is attenuated by allosteric modulation (partial agonism). Muscarinic receptor antagonists enhance affinity and efficacy of β₂-adrenergic action via allosteric sites in β₂-adrenergic receptors (synergism). In conclusion, K_Ca channels and allosterism may be novel targets of bronchodilator therapy for diseases such as asthma and COPD.

Beclomethasone dipropionate and formoterol fumarate synergistically interact in hyperresponsive medium bronchi and small airways

Background

Corticosteroids increase the expression of β₂-adrenoceptors (β₂-ARs) and protect them against down-regulation. Conversely, β₂-AR agonists improve the anti-inflammatory action of corticosteroids. Nevertheless, it is still uncertain whether adding a long-acting β₂-AR agonist (LABA) to an inhaled corticosteroid (ICS) results in an additive effect, or there is true synergy.

Therefore, the aim of this study was to pharmacologically characterize the interaction between the ICS beclomethasone diproprionate (BDP) and the LABA formoterol fumarate (FF) in a validated human ex vivo model of bronchial asthma.

Methods

Human medium and small airways were stimulated by histamine and treated with different concentrations of BDP and FF, administered alone and in combination at concentration-ratio reproducing ex vivo that of the currently available fixed-dose combination (FDC; BDP/FF 100:6 combination-ratio). Experiments were performed in non-sensitized (NS) and passively sensitized (PS) airways. The pharmacological interaction was assessed by using Bliss Independence and Unified Theory equations.

Results

BDP/FF synergistically increased the overall bronchorelaxation in NS and PS airways (+ 15.15% ± 4.02%; P < 0.05 vs. additive effect). At low-to-medium concentrations the synergistic interaction was greater in PS than in NS bronchioles (+ 16.68% ± 3.02% and + 7.27% ± 3.05%, respectively). In PS small airways a very strong synergistic interaction (Combination Index: 0.08; + 20.04% ± 2.18% vs. additive effect) was detected for the total concentrations of BDP/FF combination corresponding to 10.6 ng/ml.

Conclusion

BDP/FF combination synergistically relaxed human bronchi; the extent of such an interaction was very strong at low-to-medium concentrations in PS small airways.

Trial registration

Not applicable.

Electronic supplementary material

The online version of this article (10.1186/s12931-018-0770-7) contains supplementary material, which is available to authorized users.

The Challenges of Precision Medicine in COPD

Pheno-/endotyping chronic obstructive pulmonary disease (COPD) is really important because it provides patients with precise and personalized medicine. The central concept of precision medicine is to take individual variability into account when making management decisions. Precision medicine should ensure that patients get the right treatment at the right dose at the right time, with minimum harmful consequences and maximum efficacy. Ideally, we should search for genetic and molecular biomarker-based profiles. Given the clinical complexity of COPD, it seems likely that a panel of several biomarkers will be required to characterize pathogenetic factors and their course over time. The need for biomarkers to guide the clinical care of individuals with COPD and to enhance the possibilities of success in drug development is clear and urgent, but biomarker development is tremendously challenging and expensive, and translation of research efforts to date has been largely ineffective. Furthermore, the development of personalized treatments will require a much more detailed understanding of the clinical and biological heterogeneity of COPD. Therefore, we are still far from being able to apply precision medicine in COPD and the treatable traits and FEV₁-free approaches are attempts to precision medicine in COPD that must be considered still quite unsophisticated.

Combining long-acting bronchodilators with different mechanisms of action: A pharmacological approach to optimize bronchodilation of equine airways

The ultra long-acting β₂ -adrenoceptor agonist olodaterol plus the ultra long-acting muscarinic antagonist tiotropium bromide are known to relax equine airways. In human bronchi combining these drugs elicits a positive interaction, thus we aimed to characterize this information further in equine isolated airways stimulated by electrical field stimulation (EFS) and using the Concentration-Reduction Index (CRI) and Combination Index (CI) equations. The drugs were administered alone and together by reproducing ex vivo the concentration-ratio delivered by the currently available fixed-dose combination (1:1). The single agents elicited a significant (p < .05) concentration-dependent reduction in the EFS-induced contractility, that was synergistically improved (CI 0.18) when administered in combination (0.9 logarithms more potent, 24% more effective than the monocomponents). The drugs mixture allowed a reduction in the concentration of olodaterol from ≃1 to ≃2.3 logarithms. A favorable CRI was detected also for tiotropium bromide, whose concentration can be reduced ≃1 logarithm at medium effect levels, remaining positive up to submaximal relaxant effect in the presence of olodaterol. The combination of tiotropium bromide/olodaterol allows the reduction in the concentration of the monocomponents to achieve airway smooth muscle relaxation, thus potentially decreases the risk of adverse events when these drugs are used to treat severe asthmatic horses.

Effect of lipopolysaccharide on the responsiveness of equine bronchial tissue

Recurrent airway obstruction (RAO) is a main characteristic of horses with severe equine asthma syndrome. The presence of bacterial lipopolysaccharide (LPS) in the airways of horses is thought to play a crucial role in the clinical expression of this disorder. This study pharmacologically characterized the effect of LPS on the responsiveness of equine bronchial tissue. Equine isolated bronchi were incubated overnight with LPS (0.1-100 ng/ml) and then stimulated by electrical field stimulation (EFS). The role of capsaicin sensitive-sensory nerves (capsaicin desensitization treatment), neurokinin-2 (NK₂) receptors (blocked by GR159897), transient receptor potential vanilloid type 1 receptors (TRPV1; blocked by SB366791), and neurokinin A (NKA) were investigated. Untreated bronchi were used as control tissues. LPS (1 ng/ml) significantly increased the EFS-evoked contractility of equine bronchi compared with control tissues (+742 ± 123 mg; P < 0.001). At higher concentrations LPS induced desensitization to airways hyperresponsiveness (AHR; EC₅₀: 5.9 ± 2.6 ng/ml). Capsaicin desensitization and GR159897 significantly prevented AHR induced by LPS at EFS_1-50Hz (-197 ± 25%; P < 0.01). SB366791 inhibited AHR at very low EFS frequency (EFS_1Hz -193 ± 29%; P < 0.01 vs. LPS-treated bronchi). LPS (1 ng/ml) significantly (P < 0.01) increased 3.7 ± 0.7 fold the release of NKA compared with control bronchi. LPS induces biphasic dysfunctional bronchial contractility due to the stimulation of capsaicin sensitive-sensory nerves, increased release of NKA, and activation of NK₂ receptors, whereas TRPV1 receptors appear to play a marginal role in this response. The overnight challenge with low concentrations of LPS represents a suitable model to investigate pharmacological options that may be of value in the treatment of equine RAO.

The cholinergic anti-inflammatory pathway: an innovative treatment strategy for respiratory diseases and their comorbidities

Over the past few decades, it has been clarified that the nervous system and immune system have overlapping distributions and their interactions are critical in the regulation of immunological and inflammatory responses. The cholinergic anti-inflammatory pathway, including the parasympathetic nerve systems and humoral factors orchestrate the immune responses to protect the body during infection and tissue injury. Recent investigations have attempted to clarify how the parasympathetic nerve systems attenuate the systemic inflammatory responses and identified the α7 nicotinic acetylcholine receptor (α7nAChR) as a crucial target for attenuating the release of inflammatory cytokines from inflammatory cells including macrophages and dendritic cells. This modulatory circuit pathway possibly exists in the lungs and might be involved in regulating inflammation and immunity during infection and other inflammatory lung diseases including asthma and COPD, which means that modulation of the cholinergic anti-inflammatory pathway is a possible therapeutic target for lung diseases.