Investigating the Unbinding of Muscarinic Antagonists from the Muscarinic 3 Receptor.

Patient symptom relief is often heavily influenced by the residence time of the inhibitor-target complex. For the human muscarinic receptor 3 (hMR3), tiotropium is a long-acting bronchodilator used in conditions such as asthma or chronic obstructive pulmonary disease (COPD). The mechanistic insights into this inhibitor remain unclear; specifically, the elucidation of the main factors determining the unbinding rates could help develop the next generation of antimuscarinic agents. Using our novel unbinding algorithm, we were able to investigate ligand dissociation from hMR3. The unbinding paths of tiotropium and two of its analogues, N-methylscopolamin and homatropine methylbromide, show a consistent qualitative mechanism and allow us to identify the structural bottleneck of the process. Furthermore, our machine learning-based analysis identified key roles of the ECL2/TM5 junction involved in the transition state. Additionally, our results point to relevant changes at the intracellular end of the TM6 helix leading to the ICL3 kinase domain, highlighting the closest residue L482. This residue is located right between two main protein binding sites involved in signal transduction for hMR3's activation and regulation. We also highlight key pharmacophores of tiotropium that play determining roles in the unbinding kinetics and could aid toward drug design and lead optimization.

Tiotropium Bromide Improves Neutrophilic Asthma by Recovering Histone Deacetylase 2 Activity.

BACKGROUND: The value of tiotropium bromide (TIO) in neutrophilic asthma was meaningful in previous study. We hypothesized that TIO's mechanism of action is associated with histone deacetylase 2 (HDAC2) activity, which is key for controlling the transcription of inflammatory cytokines and usually downregulated in neutrophilic asthma. METHODS: The effects of TIO and dexamethasone (DEX) on HDAC2 activity, nuclear factor kappa B (NF-κB), and C-X-C motif chemokine ligand 1 (CXCL1) were evaluated in neutrophilic asthma mouse model (C57BL, 6-week-old). An in-vitro study was conducted using primary human bronchial/tracheal epithelial (HBE) cells from asthma patients. Western blot analyses were performed for phospho-phospholipase Cγ-1 (PLCγ-1) and inositol trisphosphate (IP3) receptors (IP3R) with treating lipopolysaccharide (LPS) and TIO. RESULTS: Ovalbumin was used to induce eosinophilic inflammation in this study. After neutrophilic asthma was induced by LPS (O+L group), HDAC2 activity was diminished with increased NF-κB activity and CXCL1 compared to the control group. TIO significantly improved NF-κB activity, CXCL1, and HDAC2 activity compared with the O+L group in in-vivo study (P < 0.05, each). Western blot analyses showed that LPS treated HBE cells from asthma patients increased PLCγ-1 and diminished IP3 receptor levels. After TIO treatment, recovery of IP3R and improved PLCγ-1 levels were observed. CONCLUSION: These results support the hypothesis that TIO modulates inflammation by recovering HDAC2 activity from the acetylcholine-stimulated inflammation cascade in neutrophilic asthma. The detailed inflammation cascade of recovering HDAC2 activity by TIO might be associated with PLCγ-1-IP3-IP3R mediated intracellular calcium ion pathway.

Effect of daily dosing with tiotropium against methacholine induced bronchoconstriction in asthmatics.

INTRODUCTION: Loss of bronchoprotection against direct and indirect acting stimuli following regular use of inhaled beta2-agonists occurs with both short and long-acting formulations. Comparatively little is known about the development of tolerance following regular use of inhaled muscarinic receptor antagonists. Two investigations with the short-acting muscarinic receptor antagonist ipratropium bromide have reported no tolerance after regular use against inhaled methacholine. To our knowledge, there are no data regarding loss of bronchoprotection following regular use of long-acting muscarinic receptor antagonist. We therefore looked at the effect of daily dosing with tiotropium on methacholine induced bronchoconstriction in a population of mild asthmatics. METHODS: We performed a randomized, double-blind, placebo-controlled cross-over study comparing tiotropium Respimat® 5 µg to placebo in adult asthmatics. Each treatment arm began with baseline methacholine challenge followed immediately by treatment administration. One hour later a post treatment methacholine challenge was performed. Participants dosed daily (two puffs) at home for the next six days and returned to the lab on Day 8 for a final dose of treatment 1 h prior to methacholine challenge. RESULTS: The average doubling dose increase in methacholine PD20 following a single dose of tiotropium was 3.9 doubling doses whereas that following placebo was 0.93 (p = 0.003). After regular use, methacholine PD20 was further increased to 6.4 doubling doses following tiotropium whereas that following placebo decreased by 0.57 doubling doses (p < 0.001). CONCLUSION: LAMA are indicated for use as add-on monotherapy or in triple therapy combination for poorly controlled asthma. It may be reassuring to know therefore, that regular use does not result in loss of bronchoprotection like that which occurs with beta2-agonist bronchodilators.

Tiotropium/Olodaterol treatment reduces cigarette smoke extract-induced cell death in BEAS-2B bronchial epithelial cells.

BACKGROUND: Cigarette smoking is a critical risk factor for the destruction of lung parenchyma or the development of emphysema, which is characteristic of COPD. Disruption of epithelial layer integrity may contribute to lung injury following cigarette smoke extract (CSE) exposure. Tiotropium/olodaterol acts as a bronchodilator for COPD treatment; however, the effect of dual bronchodilators on epithelial cell injury and its underlying mechanism remain unclear. In this study, we evaluated the effect of tiotropium/olodaterol on CSE-mediated cell death and the underlying mechanisms. METHODS: Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis, necrosis, and autophagy were evaluated using flow cytometry. Autophagy-related protein, phosphorylated ERK, expression was determined using Western blotting. RESULTS: Tiotropium/olodaterol significantly inhibited CSE-induced cell death, mitochondria dysfunction, and autophagy, which had no significant effect on apoptosis or necrosis in BEAS-2B human bronchial epithelial cells. Moreover, tiotropium/olodaterol attenuated CSE-induced upregulation of JNK. CONCLUSIONS: CSE induced cell death and caused consistent patterns of autophagy and JNK activation in BEAS-2B human bronchial epithelial cells. Tiotropium/olodaterol treatment protected bronchial epithelial cells from CSE-induced injury and inhibited activation of autophagy and upregulation of JNK phosphorylation. These results indicate that tiotropium/olodaterol may protect epithelial cells from the deleterious effects of CSE exposure, which is associated with the regulation of autophagy and JNK activation.

Tiotropium and Fluticasone Inhibit Rhinovirus-Induced Mucin Production via Multiple Mechanisms in Differentiated Airway Epithelial Cells.

Human rhinoviruses (HRVs) are associated with acute exacerbations in patients with chronic obstructive pulmonary disease (COPD) and asthma, which are accompanied by mucus hypersecretion. Whereas, various studies have shown that HRVs increase epithelial mucin production and thus may directly contribute to mucus hypersecretion. The effects of drugs used in the treatment of COPD and asthma on HRV-induced mucin production in epithelial cell cultures have not been studied. In the present study, we assessed effects of HRVs on mucin production and secretion in well-differentiated primary human bronchial epithelial cells (PBEC) and studied the effect of the inhaled corticosteroid fluticasone propionate and the long-acting muscarinic antagonist tiotropium bromide on this process. Differentiated PBEC that were cultured at the air-liquid interface (ALI-PBEC) were infected with HRV-A16 and HRV-1B. Quantitative PCR, immunofluorescence staining, ELISA, periodic acid-Schiff (PAS) staining and immunostaining assays were used to assess the effects of HRV infection. Here we demonstrate that both HRV-A16 and HRV-1B increased mucin (MUC5AC and MUC5B) gene expression and protein release. When exploring this in more detail in HRV-A16-infected epithelial cells, mucin expression was found to be accompanied by increases in expression of SAM-pointed domain-containing Ets-like factor (SPDEF) and SPDEF-regulated genes known to be involved in the regulation of mucin production. We also found that pre-treatment with the purinergic P2R antagonist suramin inhibits HRV-enhanced MUC5AC expression and protein release, implicating involvement of purinergic signaling by extracellular ATP. We furthermore found that both fluticasone and tiotropium decreased HRV-induced mucin production without affecting viral replication, and obtained evidence to suggest that the inhibitory effect of fluticasone involved modulation of SPDEF-regulated genes and extracellular ATP release. These data show that both tiotropium and fluticasone inhibit HRV-induced epithelial mucin production independent of viral clearance, and thus provide insight into the mechanisms underlying beneficial effects of tiotropium and fluticasone in the treatment of COPD, asthma and accompanying exacerbations in these patients. Furthermore, our findings provide additional insight into the mechanisms by which HRV increases epithelial mucin production.

Emerging muscarinic receptor antagonists for the treatment of asthma.

INTRODUCTION: The increased acetylcholine signaling in asthma pathophysiology offers the rationale for the use of LAMAs in the treatment of asthmatic patients. Tiotropium is still the only LAMA approved for use in asthma but there is a real interest in developing novel LAMAs for the treatment of asthma, or at least to extend this indication to other LAMAs already on the market. AREAS COVERED: We examined and discussed trials and research that have studied or are evaluating the role of LAMAs already on the market in asthma and possible novel muscarinic acetylcholine receptor antagonists. EXPERT OPINION: Glycopyrronium and umeclidinium will soon be included in the GINA strategy with the same current indications of tiotropium. It is likely that the choice of the LAMA will be influenced not so much by its pharmacological profile as by the type of triple therapy chosen. It is extremely difficult to identify a new LAMA that is more effective than tiotropium, but is it plausible that new technologies that will allow delivering the drug in a more targeted way and with a lower risk of adverse effects may represent the real progress in the use of LAMAs in asthma in the coming years.

Functional analysis of OCTN2 and ATB0,+ in normal human airway epithelial cells.

In human, OCTN2 (SLC22A5) and ATB0,+ (SLC6A14) transporters mediate the uptake of L-carnitine, essential for the transport of fatty acids into mitochondria and the subsequent degradation by ß-oxidation. Aim of the present study was to characterize L-carnitine transport in EpiAirway™, a 3D organotypic in vitro model of primary human tracheal-bronchial epithelial cells that form a fully differentiated, pseudostratified columnar epithelium at air-liquid interface (ALI) condition. In parallel, Calu-3 monolayers grown at ALI for different times (8d or 21d of culture) were used as comparison. OCTN2 transporter was equally expressed in both models and functional at the basolateral side. ATB0,+ was, instead, highly expressed and active on the apical membrane of EpiAirway™ and only in early-cultures of Calu-3 (8d but not 21d ALI). In both cell models, L-carnitine uptake on the apical side was significantly inhibited by the bronchodilators glycopyrrolate and tiotropium, that hence can be considered substrates of ATB0,+; ipratropium was instead effective on the basolateral side, indicating its interaction with OCTN2. Inflammatory stimuli, such as LPS or TNFα, caused an induction of SLC6A14/ATB0,+ expression in Calu-3 cells, along with a 2-fold increase of L-carnitine uptake only at the apical side; on the contrary SLC22A5/OCTN2 was not affected. As both OCTN2 and ATB0,+, beyond transporting L-carnitine, have a significant potential as delivery systems for drugs, the identification of these transporters in EpiAirway™ can open new fields of investigation in the study of drug inhalation and pulmonary delivery.

Effect of Tiotropium Bromide on Airway Inflammation and Programmed Cell Death 5 in a Mouse Model of Ovalbumin-Induced Allergic Asthma.

Rationale: We previously demonstrated increased expression of programmed cell death 5 (PDCD5) in asthmatic patients and ovalbumin-induced allergic asthma. International guidelines (GINA 2019) have included the use of tiotropium bromide for chronic treatment of the most severe and frequently exacerbated asthma in patients ≥6 years old, who do not have good response to inhaled corticosteroids. Objective: To explore the role of tiotropium and its effect on PDCD5 level in a mouse model of chronic asthma. Methods: We divided 12 female mice into 2 groups: untreated asthma (n = 6) and tiotropium-treated asthma (n = 6). The impact of tiotropium was assessed by histology of lung tissue and morphometry. Pulmonary function was tested by using pressure sensors. The number of cells in bronchoalveolar lavage fluid (BALF) was detected. Levels of PDCD5, active caspase-3, and muscarinic acetylcholine receptors M2 (ChRM2) and M3 (ChRM3) were examined. Results: Tiotropium treatment significantly reduced airway inflammation and remodeling in asthmatic mice and intensified the lung function. PDCD5 level was reduced with tiotropium (p < 0.05). Moreover, active caspase-3 level was decreased with tiotropium (p < 0.001), and ChRM3 level was increased. Conclusions: Tiotropium treatment may alleviate the pathological changes with asthma by regulating apoptosis.

Tiotropium inhibits proinflammatory microparticle generation by human bronchial and endothelial cells.

Tiotropium is a muscarinic antagonist that reduces the risk of acute exacerbations of chronic obstructive pulmonary disease, possibly through an as yet incompletely characterized anti-inflammatory activity. We hypothesized that muscarinic activation of bronchial epithelial cells and endothelial cells causes the release of proinflammatory microparticles and that tiotropium inhibits the phenomenon. Microparticle generation was assessed by a functional assay, by flow cytometry and by NanoSight technology. Immortalized bronchial epithelial cells (16HBE) and umbilical vein endothelial cells were treated with acetylcholine in the presence of varying concentrations of tiotropium. Intracellular calcium concentration, extracellular regulated kinase phosphorylation and chemokine content in the conditioned media were assessed by commercial kits. Acetylcholine causes microparticle generation that is completely inhibited by tiotropium (50 pM). Microparticles generated by acetylcholine-stimulated cells increase the synthesis of proinflammatory mediators in an autocrine fashion. Acetylcholine-induced upregulation of microparticle generation is inhibited by an inhibitor of extracellular regulated kinase phosphorylation and by a phospholipase C inhibitor. Tiotropium blocks both extracellular regulated kinase phosphorylation and calcium mobilization, consistent with the hypothesis that the drug prevents microparticle generation through inhibition of these critical pathways. These results might contribute to explain the effect of tiotropium in reducing acute exacerbations of chronic obstructive pulmonary disease.

Tiotropium/Olodaterol: A Review in COPD.

Tiotropium/olodaterol (Stiolto® Respimat®; Spiolto® Respimat®) is an inhaled fixed-dose combination of the long-acting muscarinic antagonist tiotropium bromide (hereafter referred to as tiotropium) and the long-acting ß2-adrenergic agonist olodaterol. It is available in several countries, including the USA, Japan, China and those of the EU, where it is indicated for the long-term maintenance treatment of patients with chronic obstructive pulmonary disease (COPD). The efficacy of tiotropium/olodaterol 5/5 µg/day in patients with COPD was evaluated in phase III or IV trials of 6-52 weeks' duration. Tiotropium/olodaterol improved lung function to a greater extent than each of its individual components or placebo in 12- and 52-week trials. In 6-week trials, tiotropium/olodaterol provided greater lung function benefits over 24 h than the individual components, placebo or twice-daily fluticasone propionate/salmeterol. Tiotropium/olodaterol also demonstrated beneficial effects on health-related quality of life (HR-QoL), dyspnoea, inspiratory capacity, exercise endurance and the need for rescue medication. In an 8-week open-label trial, umeclidinium/vilanterol was superior to tiotropium/olodaterol for the primary endpoint of trough forced expiratory volume in 1 s. The tolerability profile of tiotropium/olodaterol was generally similar to that of the individual components. In conclusion, tiotropium/olodaterol provides a useful option for the maintenance treatment of COPD, with the convenience of once-daily administration via a single inhaler.

Second M3 muscarinic receptor binding site contributes to bronchoprotection by tiotropium.

BACKGROUND AND PURPOSE: The bronchodilator tiotropium binds not only to its main binding site on the M3 muscarinic receptor but also to an allosteric site. Here, we have investigated the functional relevance of this allosteric binding and the potential contribution of this behaviour to interactions with long-acting ß-adrenoceptor agonists, as combination therapy with anticholinergic agents and ß-adrenoceptor agonists improves lung function in chronic obstructive pulmonary disease. EXPERIMENTAL APPROACH: ACh, tiotropium, and atropine binding to M3 receptors were modelled using molecular dynamics simulations. Contractions of bovine and human tracheal smooth muscle strips were studied. KEY RESULTS: Molecular dynamics simulation revealed extracellular vestibule binding of tiotropium, and not atropine, to M3 receptors as a secondary low affinity binding site, preventing ACh entry into the orthosteric binding pocket. This resulted in a low (allosteric binding) and high (orthosteric binding) functional affinity of tiotropium in protecting against methacholine-induced contractions of airway smooth muscle, which was not observed for atropine and glycopyrrolate. Moreover, antagonism by tiotropium was insurmountable in nature. This behaviour facilitated functional interactions of tiotropium with the ß-agonist olodaterol, which synergistically enhanced bronchoprotective effects of tiotropium. This was not seen for glycopyrrolate and olodaterol or indacaterol but was mimicked by the interaction of tiotropium and forskolin, indicating no direct ß-adrenoceptor-M3 receptor crosstalk in this effect. CONCLUSIONS AND IMPLICATIONS: We propose that tiotropium has two binding sites at the M3 receptor that prevent ACh action, which, together with slow dissociation kinetics, may contribute to insurmountable antagonism and enhanced functional interactions with ß-adrenoceptor 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 ß2-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.

Pharmacological characterization of the interaction between tiotropium bromide and olodaterol on human bronchi and small airways.

Combining a long-acting ß2-agonist (LABA) with a long-acting muscarinic antagonist (LAMA) is the cornerstone to treat patients with chronic obstructive pulmonary disease (COPD). In this study we have characterized the interaction between the LAMA tiotropium bromide, and the LABA olodaterol, on the contractile tone of human medium bronchi and small airways. The response to a combination of tiotropium bromide and olodaterol was assessed at sub-maximal contractile tone induced by carbachol. The duration of action was studied in tissue contracted by transmural stimulation. Relaxation of bronchial tone was expressed as % of maximal response to papaverine. Drug interactions were analyzed by the Bliss Independence method and Unified Theory. Tiotropium bromide/olodaterol combination induced a significant synergistic relaxant response (P < 0.05 vs. expected additive effect) in medium bronchi and small airways pre-contracted by carbachol, by enhancing relaxation +22.13 ± 4.42% and +26.31 ± 12.39%, respectively. The combination of tiotropium bromide and olodaterol also reduced the airway smooth muscle contractility elicited by transmural stimulation by 73.60 ± 3.10%. The extent of synergy was strong to very strong, and was supported by the release of neuronal acetylcholine, cyclic adenosine monophosphate levels, and activation of iberiotoxin-sensitive KCa++ channels. Conversely, the interaction between tiotropium bromide and olodaterl was independent of the activity at M2 muscarinic receptors. These results indicate that tiotropium bromide/olodaterol combination leads to a potent and durable synergistic relaxation of human medium bronchi and small airways. Further pharmacological studies are needed to confirm these results in clinical settings.

Tiotropium for asthma: A summary of current guidelines and a case study.

BACKGROUND AND PURPOSE: The long-acting muscarinic antagonist tiotropium received an indication for the treatment of asthma from the FDA in 2015. METHODS: This paper summarizes much of the published findings on tiotropium and asthma and explores the heterogeneity of the asthma population vis-à-vis recent changes in guidelines for management of COPD. The accompanying case study provides an illustration of how tiotropium might be added to a patient's regimen appropriately. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: Tiotropium has been shown in many studies to be beneficial to patients with asthma as an add-on medication. It should be considered as an agent by the clinician managing patients with both allergic and non-allergic asthma.

Efficacy of budesonide/formoterol and tiotropium combination for the treatment of Chinese patients with chronic obstructive pulmonary disease.

This study investigated the efficacy and safety of budesonide/formoterol (B/F) and tiotropium combination in the management of chronic obstructive pulmonary disease (COPD) in Chinese patients.Between January 2015 and November 2017, 113 eligible Chinese patients with COPD were included and divided into an intervention group and a control group. Sixty-three patients in the intervention group underwent B/F combined tiotropium, while 50 patients in the control group received tiotropium alone. The primary outcome was severity of dyspnea on exertion (DOE), measured by the 6-minute walk test (6MWT) scale. The secondary outcomes included lung function, measured by the forced expiratory volume in 1 second (FEV1), quality of life, measured by the St. George's Respiratory Questionnaire (SGRQ), and adverse events. All outcomes were measured at the end of 12-week treatment.B/F and tiotropium combination showed greater efficacy in DOE (P < .01), lung function (P < .01), and quality of life (P < .01), compared with tiotropium alone at the end of 12-week treatment. In addition, adverse events in both groups were similar and tolerable.The findings suggest that B/F and tiotropium combination can be used as an effective treatment in Chinese patients with COPD.

Tiotropium inhibits methacholine-induced extracellular matrix production via ß-catenin signaling in human airway smooth muscle cells.

Background: Airway remodeling is an important feature of chronic obstructive pulmonary disease (COPD) that is associated with disease severity and irreversible airflow limitation. An extensive alteration of the extracellular matrix (ECM) surrounding the airway smooth muscle (ASM) bundle is one of the pathological manifestations of airway remodeling, which contributes to the decline in lung function. Tiotropium, a long-acting inhaled muscarinic receptor antagonist, has been confirmed to play a role in preventing airway remodeling including ECM deposition beyond bronchodilation in vivo, but the relationship between ASM cell (ASMC) relaxation and ECM production remains unclear. Purpose: In this study, we attempted to investigate the influence of tiotropium on ECM production by ASMCs and the underlying mechanism. Methods: Tiotropium was added 30 minutes before the addition of methacholine to primary cultured human ASMCs. Protein expression was analylized by Western Blot and mRNA abundance was determined by real-time PCR. Results: We found that tiotropium reduced collagen I protein expression, and the mRNA abundance of collagen I, fibronectin, and versican. ß-catenin signaling was inactivated by inhibiting glycogen synthase kinase 3ß (GSK3ß) phosphorylation in this process. Tiotropum inhibited the amount of active ß-catenin and its transcription activity. Furthermore, overexpression of active ß-catenin by adenoviruses carrying the S33Y mutant resisted the suppressive effect of tiotropium on collagen I protein expression. However, silencing ß-catenin by specific small interfering RNA enhanced the negative effect of tiotropium. Conclusion: These findings suggest that relaxation of ASMCs by tiotropium can prevent ECM production through ß-catenin signaling.

Tiotropium for the Treatment of Asthma: Patient Selection and Perspectives.

Asthma is a chronic disease of airway inflammation with a large global burden. Despite established, guideline-based stepwise therapy, a significant proportion of patients remain symptomatic and poorly controlled. As such, there is a need for additional safe, effective, convenient, and cost-effective therapies that can be broadly applied across a range of asthma phenotypes. Tiotropium is a long-acting muscarinic antagonist (LAMA) that leads to bronchodilation by blocking endogenous acetylcholine receptors in the airways. Tiotropium has long been approved for the treatment of chronic obstructive pulmonary disease, and it has recently been recognized for its safety and efficacy in improving lung function and controlling asthma. Evidence from several Phase III trials in the adult and paediatric population has shown that tiotropium is well tolerated and significantly improves a range of endpoints as an add-on treatment to ICS therapy, regardless of baseline characteristics and clinical phenotypes. Consequently, regulatory authorities worldwide have recently licensed tiotropium as the only LAMA approved for the treatment of asthma. This review provides an overview of safety and efficacy data and discusses the use of tiotropium in patients across the range of asthma severities, ages, and phenotypes.

Protective effects of tiotropium alone or combined with budesonide against cadmium inhalation induced acute neutrophilic pulmonary inflammation in rats.

As a potent bronchodilator, the anti-inflammatory effects of tiotropium and its interaction with budesonide against cadmium-induced acute pulmonary inflammation were investigated. Compared to values obtained in rats exposed to cadmium, cytological analysis indicated a significant decrease of total cell and neutrophil counts and protein concentration in bronchoalveolar lavage fluid (BALF) in rats pretreated with tiotropium (70µg/15ml or 350µg/15ml). Zymographic tests showed a decrease of MMP-2 activity in BALF in rats pretreated only with high concentration of tiotropium. Histological examination revealed a significant decrease of the severity and extent of inflammatory lung injuries in rats pretreated with both tested concentrations of tiotropium. Though tiotropium (70µg/15ml) or budesonide (250µg/15ml) could not reduce cadmium-induced bronchial hyper-responsiveness, their combination significantly decreased bronchial contractile response to methacholine. These two drugs separately decreased the neutrophil number and protein concentration in BALF but no significant interaction was observed when both drugs were combined. Although no inhibitory effects on MMP-2 and MMP-9 was observed in rats pretreated with budesonide alone, the combination with the ineffective dose of tiotropium induced a significant reduction on these parameters. The inhibitory effect of tiotropium on lung injuries was not influenced by budesonide which alone induced a limited action on the severity and extent of inflammatory sites. Our findings show that tiotropium exerts anti-inflammatory effects on cadmium-induced acute neutrophilic pulmonary inflammation. The combination of tiotropium with budesonide inhibits cadmium-induced inflammatory injuries with a synergistic interaction on MMP-2 and MMP-9 activity and airway hyper-responsiveness.

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

The ultra long-acting ß2 -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.