Emerging drugs for chronic obstructive pulmonary disease

Porcine CXCR1/2 antagonist CXCL8(3-72)G31P inhibits lung inflammation in LPS-challenged mice

Swine pneumonia is a great threat for pig industry around the world, which is usually accompanied with neutrophils infiltration in the airway. Although interleukin-8 (CXCL8) and its receptors, CXC chemokine receptor 1 and 2 (CXCR1/2) in human have been well documented, the expression and function of CXCR1/2 is still unknown in swine. To explore the feasibility to develop new veterinary anti-inflammatory drugs targeting porcine CXCR1/2, we detected CXCR1/2 expression in swine pneumonia through Real-Time PCR and immunohistochemistry for the first time. Two porcine CXCR1/2 antagonists, CXCL8(3-72)N11R/G31P (pN11R) and CXCL8(3-72)G31P (pG31P) were prepared and their anti-inflammatory effects were evaluated using cell chemotaxis assays and animal experiments. Our data showed that CXCR1/2 expression, which was closely related to neutrophil infiltration in the lung, was significantly up-regulated in swine pneumonia. The pN11R and pG31P could effectively inhibit the directional migration of neutrophils in vitro. In vivo data also indicated that both pN11R and pG31P significantly relieved LPS-induced pneumonia in mice through decreasing the expression of TNF-α, CXCL8, and IL-1β, and inhibiting neutrophil influx into the lung. pG31P was more efficient. Our study suggested that it is possible to develop new veterinary anti-inflammatory drugs targeting porcine CXCR1/2, and pG31P is a promising candidate.

Nucleic Acid-Based Therapeutics for Pulmonary Diseases

Nucleic acid-based therapeutics present huge potential in the treatment of pulmonary diseases ranging from lung cancer to asthma and chronic pulmonary diseases, which are often fatal and widely prevalent. The susceptibility of nucleic acids to degradation and the complex structure of lungs retard the effective pulmonary delivery of nucleic acid drug. To overcome these barriers, different strategies have been exploited to increase the delivery efficiency using chemically synthesized nucleic acids, vector encapsulation, proper formulation, and administration route. However, several limitations regarding off-target effects and immune stimulation of nucleic acid drugs hamper their translation into the clinical practice. Therefore, their successful clinical application will ultimately rely on well-developed carriers and methods to ensure safety and efficacy. In this review, we provide a comprehensive overview of the nucleic acid application for pulmonary diseases, covering action mechanism of the nucleic acid drugs, the novel delivery systems, and the current formulation for the administration to lungs. The latest advances of nucleic acid drugs under clinical evaluation to treat pulmonary disorders will also be detailed.

Role of statins and mevalonate pathway on impaired HDAC2 activity induced by oxidative stress in human airway epithelial cells

In patients with chronic obstructive pulmonary disease (COPD) the inflammatory response is often steroid-resistant, likely since oxidative stress and cigarette smoking impair histone deacetylase 2 (HDAC2) activity. Since it has been demonstrated that statins may restore the HDAC2 activity in cultured human endothelial cells, the aim of this study was to investigate the effects of statins in reversing the steroid-resistance induced by oxidative stress. We evaluated the effects of simvastatin and dexamethasone on HDAC2 expression and activity, and the role of mevalonate and Rho/ROCK pathways in A549 cells, a human lung type II epithelial cell line stressed with H₂O₂. Our results documented that H₂O₂ significantly reduced the HDAC2 expression and activity. In H₂O₂ treated cells dexamethasone was unable to restore the activity of HDAC2, whereas simvastatin restored both the expression and the activity of this enzyme. Our data also showed that mevalonate reduced the activity of HDAC2 whereas Y27632, a Rho/ROCK inhibitor, had no effect on HDAC2 activity when co-administered with simvastatin. Our data suggest that statins could have the potential to restore corticosteroid sensitivity in A549 cells. The evidences of this study suggest that, although both mevalonate and Rho/ROCK pathways are involved in the detrimental effect elicited by oxidative stress, statins may restore the function and expression of depleted HDAC2 via modulating the mevalonate cascade, at least in A549 cells. In conclusion, the modulation of histone acetyltransferase/deacetylase activity may lead to the development of novel anti-inflammatory approaches to inflammatory lung diseases that are currently difficult to treat.

Pharmacological treatments in asthma-affected horses: A pair-wise and network meta-analysis

BACKGROUND

Equine asthma is a disease characterised by reversible airflow obstruction, bronchial hyper-responsiveness and airway inflammation following exposure of susceptible horses to specific airborne agents. Although clinical remission can be achieved in a low-airborne dust environment, repeated exacerbations may lead to irreversible airway remodelling. The available data on the pharmacotherapy of equine asthma result from several small studies, and no head-to-head clinical trials have been conducted among the available medications.

OBJECTIVES

To assess the impact of the pharmacological interventions in equine asthma and compare the effect of different classes of drugs on lung function.

STUDY DESIGN

Pair-wise and network meta-analysis.

METHODS

Literature searches for clinical trials on the pharmacotherapy of equine asthma were performed. The risk of publication bias was assessed by funnel plots and Egger's test. Changes in maximum transpulmonary or pleural pressure, pulmonary resistance and dynamic lung compliance vs. control were analysed via random-effects models and Bayesian networks.

RESULTS

The results obtained from 319 equine asthma-affected horses were extracted from 32 studies. Bronchodilators, corticosteroids and chromones improved maximum transpulmonary or pleural pressure (range: -8.0 to -21.4 cmH₂ O; P<0.001). Bronchodilators, corticosteroids and furosemide reduced pulmonary resistance (range: -1.2 to -1.9 cmH₂ O/L/s; P<0.001), and weakly increased dynamic lung compliance. Inhaled β₂ -adrenoreceptor (β₂ -AR) agonists and inhaled corticosteroids had the highest probability of being the best therapies. Long-term treatments were more effective than short-term treatments.

MAIN LIMITATIONS

Weak publication bias was detected.

CONCLUSIONS

This study demonstrates that long-term treatments with inhaled corticosteroids and long-acting β₂ -AR agonists may represent the first choice for treating equine asthma. Further high quality clinical trials are needed to clarify whether inhaled bronchodilators should be preferred to inhaled corticosteroids or vice versa, and to investigate the potential superiority of combination therapy in equine asthma.

Brain natriuretic peptide: Much more than a biomarker

Brain natriuretic peptide (BNP) modulates several biological processes by activating the natriuretic peptide receptor A (NPR-A). Atria and ventricles secrete BNP. BNP increases natriuresis, diuresis and vasodilatation, thus resulting in a decreased cardiac workload. BNP and NT-proBNP, which is the biologically inactive N-terminal portion of its pro-hormone, are fast and sensitive biomarkers for diagnosing heart failure. The plasma concentrations of both BNP and NT-proBNP also correlate with left ventricular function in patients with acute exacerbation of COPD, even without history of heart failure. Several studies have been conducted in vitro and in vivo, both in animals and in humans, in order to assess the potential role of the NPR-A activation as a novel therapeutic approach for treating obstructive pulmonary disorders. Unfortunately, these studies have yielded conflicting results. Nevertheless, further recent specific studies, performed in ex vivo models of asthma and COPD, have confirmed the bronchorelaxant effect of BNP and its protective role against bronchial hyperresponsiveness in human airways. These studies have also clarified the intimate mechanism of action of BNP, represented by an autocrine loop elicited by the activation of NPR-A, localized on bronchial epithelium, and the relaxant response of the surrounding ASM, which does not expresses NPR-A. This review explores the teleological activities and paradoxical effects of BNP with regard to chronic obstructive respiratory disorders, and provides an excursus on the main scientific findings that explain why BNP should be considered much more than a biomarker.

Neutrophil proteases alter the interleukin-22-receptor-dependent lung antimicrobial defence

Chronic obstructive pulmonary disease (COPD) is punctuated by episodes of infection-driven acute exacerbations. Despite the life-threatening nature of these exacerbations, the underlying mechanisms remain unclear, although a high number of neutrophils in the lungs of COPD patients is known to correlate with poor prognosis. Interleukin (IL)-22 is a cytokine that plays a pivotal role in lung antimicrobial defence and tissue protection. We hypothesised that neutrophils secrete proteases that may have adverse effects in COPD, by altering the IL-22 receptor (IL-22R)-dependent signalling.Using in vitro and in vivo approaches as well as reverse transcriptase quantitative PCR, flow cytometry and/or Western blotting techniques, we first showed that pathogens such as the influenza virus promote IL-22R expression in human bronchial epithelial cells, whereas Pseudomonas aeruginosa, bacterial lipopolysaccharide or cigarette smoke do not. Most importantly, neutrophil proteases cleave IL-22R and impair IL-22-dependent immune signalling and expression of antimicrobial effectors such as β-defensin-2. This proteolysis resulted in the release of a soluble fragment of IL-22R, which was detectable both in cellular and animal models as well as in sputa from COPD patients with acute exacerbations.Hence, our study reveals an unsuspected regulation by the proteolytic action of neutrophil enzymes of IL-22-dependent lung host response. This process probably enhances pathogen replication, and ultimately COPD exacerbations.

Pharmacological interaction between LABAs and LAMAs in the airways: optimizing synergy

Nowadays there is solid clinical information for combining β2-agonists and anti-muscarinic agents, although the nature (additive or synergistic) of the net clinical result obtained by co-administration of these two classes of bronchodilators is not completely elucidated from a pharmacological point of view. Recent preclinical studies demonstrated that combining a long-acting β2-agonist (LABA) with a long-acting anti-muscarinic agent (LAMA) provides synergistic benefit on airway smooth muscle relaxation, which may have major implications for the use of LABA/LAMA combinations in the treatment COPD. Indeed, the LABA/LAMA synergism has been proved also in patients with moderate-to-severe COPD. Nevertheless, there is still a strong medical need for dose-finding clinical trials designed to identify the most favourable doses of LABA/LAMA combinations able to induce a real synergism. We strongly believe that the Bliss Independence theory represents an effective model for investigating the cross-talk between β2-adrenoreceptor and the muscarinic pathways leading to the synergistic interaction between β2-agonists and anti-muscarinic agents. In any case, the possibility of eliciting a synergistic bronchodilator effect when combining a LABA and a LAMA suggests that the therapeutic approach proposed by GOLD recommendations to only use LABA/LAMA combination in more severe COPD patients who are not controlled by a single bronchodilator should be reconsidered. We support the possibility of an early intervention with low doses of LABA/LAMA combination to optimize bronchodilation and reduce the risk of adverse events that characterize both LABAs and LAMAs, especially when administered at the full doses currently approved for the treatment of COPD.

Pharmacological characterization of the interaction between the dual phosphodiesterase (PDE) 3/4 inhibitor RPL554 and glycopyrronium on human isolated bronchi and small airways

BACKGROUND

The dual PDE3/4 inhibitor RPL 554 causes bronchodilation in patients with asthma or COPD and synergistically interacts with muscarinic receptor antagonists in relaxing human isolated bronchi in acute experimental settings. In the present study we investigated the long-lasting interaction between RPL554 and glycopyrronium by testing these drugs for their ability to relax both medium and small human isolated bronchi.

METHODS

The relaxant effect and duration of action of RPL554 and glycopyrronium, alone, or in combination, were studied on the contractile tone induced by electrical field stimulation (EFS) or carbachol in medium and small human isolated bronchi. Relaxation was expressed as percentage of maximal response and synergy analyzed by Bliss Independence theory.

RESULTS

Low concentrations of RPL554 and glycopyrronium induced maximal relaxation of medium bronchi at 160 ± 20 min and 50 ± 10 min, respectively, an effect detectable for at least 4 h. Maximal synergy was observed at ≃ 2 hrs (-71.4 ± 5.1%), and the combination extended the relaxation to at least 6 hrs, when the contractile tone was -41.2 ± 8.5% of the control responses. The combination induced the greatest effectiveness for EFS at 3 Hz and low-to-middle concentrations also produced significant synergism on small airways (21.1 ± 4.0%,P < 0.05), compared with the additive response. The combination induced lumen area enhancement of 69.1 ± 2.4% (P < 0.05), compared with the additive response (51.0 ± 5.4%).

CONCLUSIONS

RPL554 and glycopyrronium demonstrated a synergistic interaction in relaxing both human medium and small isolated bronchi, in terms of peak relaxation and an extended duration of action, suggesting that this combination may have a beneficial role in the treatment of asthma or COPD.

Prevention of acute exacerbations of COPD: American College of Chest Physicians and Canadian Thoracic Society Guideline

BACKGROUND

COPD is a major cause of morbidity and mortality in the United States as well as throughout the rest of the world. An exacerbation of COPD (periodic escalations of symptoms of cough, dyspnea, and sputum production) is a major contributor to worsening lung function, impairment in quality of life, need for urgent care or hospitalization, and cost of care in COPD. Research conducted over the past decade has contributed much to our current understanding of the pathogenesis and treatment of COPD. Additionally, an evolving literature has accumulated about the prevention of acute exacerbations.

METHODS

In recognition of the importance of preventing exacerbations in patients with COPD, the American College of Chest Physicians (CHEST) and Canadian Thoracic Society (CTS) joint evidence-based guideline (AECOPD Guideline) was developed to provide a practical, clinically useful document to describe the current state of knowledge regarding the prevention of acute exacerbations according to major categories of prevention therapies. Three key clinical questions developed using the PICO (population, intervention, comparator, and outcome) format addressed the prevention of acute exacerbations of COPD: nonpharmacologic therapies, inhaled therapies, and oral therapies. We used recognized document evaluation tools to assess and choose the most appropriate studies and to extract meaningful data and grade the level of evidence to support the recommendations in each PICO question in a balanced and unbiased fashion.

RESULTS

The AECOPD Guideline is unique not only for its topic, the prevention of acute exacerbations of COPD, but also for the first-in-kind partnership between two of the largest thoracic societies in North America. The CHEST Guidelines Oversight Committee in partnership with the CTS COPD Clinical Assembly launched this project with the objective that a systematic review and critical evaluation of the published literature by clinical experts and researchers in the field of COPD would lead to a series of recommendations to assist clinicians in their management of the patient with COPD.

CONCLUSIONS

This guideline is unique because it provides an up-to-date, rigorous, evidence-based analysis of current randomized controlled trial data regarding the prevention of COPD exacerbations.

Simvastatin Increases the Ability of Roflumilast N-oxide to Inhibit Cigarette Smoke-Induced Epithelial to Mesenchymal Transition in Well-differentiated Human Bronchial Epithelial Cells in vitro

BACKGROUND

Cigarette smoking contributes to epithelial-mesenchymal transition (EMT) in COPD small bronchi as part of the lung remodeling process. We recently observed that roflumilast N-oxide (RNO), the active metabolite of the PDE4 inhibitor roflumilast, prevents cigarette smoke-induced EMT in differentiated human bronchial epithelial cells. Further, statins were shown to protect renal and alveolar epithelial cells from EMT.

OBJECTIVES

To analyze how RNO and simvastatin (SIM) interact on CSE-induced EMT in well-differentiated human bronchial epithelial cells (WD-HBEC) from small bronchi in vitro.

METHODS

WD-HBEC were stimulated with CSE (2.5%). The mesenchymal markers vimentin, collagen type I and α-SMA, the epithelial markers E-cadherin and ZO-1, as well as β-catenin were quantified by real time quantitative PCR or Western blotting. Intracellular reactive oxygen species (ROS) were measured using the H2DCF-DA probe. GTP-Rac1 and pAkt were evaluated by Western blotting.

RESULTS

The combination of RNO at 2 nM and SIM at 100 nM was (over) additive to reverse CSE-induced EMT. CSE-induced EMT was partially mediated by the generation of ROS and the activation of the PI3K/Akt/β-catenin pathway. Both RNO at 2 nM and SIM at 100 nM partially abrogated this pathway, and its combination almost abolished ROS/ PI3K/Akt/β-catenin signaling and therefore EMT.

CONCLUSIONS

The PDE4 inhibitor roflumilast N-oxide acts (over)additively with simvastatin to prevent CSE-induced EMT in WD-HBEC in vitro.

Effect of the mixed phosphodiesterase 3/4 inhibitor RPL554 on human isolated bronchial smooth muscle tone

The phosphodiesterase (PDE) enzyme family hydrolyzes cAMP and cGMP, second messengers that regulate a variety of cellular processes, including airway smooth muscle (ASM) relaxation and the inhibition of inflammatory cells. We investigated the activity of RPL554 [9,10-dimethoxy-2(2,4,6-trimethylphenylimino)-3-(n-carbamoyl-2-aminoethyl)-3,4,6,7-tetrahydro-2H-pyrimido[6,1-a]isoquinolin-4-one], a dual PDE3/PDE4 inhibitor that exhibits bifunctional activity for its effects on the tone of human isolated ASM and any potential synergistic interactions with muscarinic receptor antagonists or a β2-agonist. We evaluated the influence of RPL554 on the contractile response induced by electrical field stimulation (EFS), acetylcholine (ACh), or histamine on human isolated bronchi. We also analyzed the potential synergistic effect of RPL554 in combination with atropine, glycopyrollate, or salbutamol by using the Berenbaum Bliss Independence (BI), or the dose equivalence methods. RPL554 inhibited the contraction induced by EFS [maximal effectiveness (Emax) 91.33 ± 3.37%, P < 0.001], relaxed bronchi precontracted with ACh (Emax 94.62 ± 2.63%, pD2 4.84 ± 0.12, P < 0.001), and abolished the contraction induced by histamine. Analysis of interactions indicated a weak synergism between RPL554 and salbutamol (interaction index: 0.25 ± 0.06; BI Δeffect: 0.29 ± 0.11; dose equivalence: no synergism) but significant synergism between RPL554 and atropine (interaction index: 0.09 ± 0.07; BI Δeffect: 0.54 ± 0.09; dose equivalence: synergism for low concentrations) or glycopyrrolate (ACh: BI Δeffect 0.46 ± 0.03, Berenbaum Δeffect 0.42 ± 0.02; histamine: BI Δeffect 0.46 ± 0.03, Berenbaum Δeffect 0.42 ± 0.03). This study demonstrates that RPL554 relaxes human bronchi and that it can interact with a muscarinic receptor antagonist to produce a synergistic inhibition of ASM tone. These results suggest that RPL554 may provide a novel treatment of airway diseases, either alone or in combination with antimuscarinic drugs.

Aclidinium bromide for the treatment of chronic obstructive pulmonary disease

INTRODUCTION

Although there are some challenges with current therapies, the growing evidence that tiotropium bromide is important in the maintenance treatment of chronic obstructive pulmonary disease (COPD) has led to enthusiastic investigation in search of novel muscarinic antagonists which share some of the beneficial characteristics of tiotropium and perhaps improve upon less desirable ones.

AREAS COVERED

Aclidinium bromide is a new muscarinic antagonist that has been developed to relieve symptoms in patients with COPD. Preclinical data showed that it has an intriguing pharmacodynamic and pharmacokinetic profile. Aclidinium bromide was initially assessed as a once-daily bronchodilator. Subsequently, it has been evaluated as a twice-daily agent to increase the size of the clinical effect. Pivotal Phase III trials have documented that aclidinium bromide 400 μg twice-daily shows clinically meaningful effects in lung function and other important supportive outcomes, such as health-related quality of life, dyspnea and night-time/early morning symptoms, and is safe.

EXPERT OPINION

Aclidinium bromide can to be used as an alternative to tiotropium or a long-acting β₂-agonist. It is likely that the device used to deliver aclidinium, Genuair inhaler, a novel, multidose and a breath-actuated dry powder inhaler (DPI), will be important for the possible success of this drug. However, additional Phase III trials to assess advantages over tiotropium bromide and long-acting β₂-agonists are required to allow the place of aclidinium bromide to be fully elucidated.

Impact of soluble epoxide hydrolase and epoxyeicosanoids on human health

The presence of epoxyeicosatrienoic acids (EETs) in tissues and their metabolism by soluble epoxide hydrolase (sEH) to 1,2-diols were first reported 30 years ago. However, appreciation of their importance in cell biology and physiology has greatly accelerated over the past decade with the discovery of metabolically stable inhibitors of sEH, the commercial availability of EETs, and the development of analytical methods for the quantification of EETs and their diols. Numerous roles of EETs in regulatory biology now are clear, and the value of sEH inhibition in various animal models of disease has been demonstrated. Here, we review these results and discuss how the pharmacological stabilization of EETs and other natural epoxy-fatty acids could lead to possible disease therapies.

Treatment of COPD: moving beyond the lungs

We still do not know whether the successful treatment of the comorbid diseases associated with COPD, mainly cardiovascular disease, also positively influences the course of the lung disease because so far there are few definite data documenting that treatment of COPD comorbidities will reduce morbidity and mortality rates in these patients. Observational studies suggest that COPD patients treated with statins, angiotensin-converting enzyme inhibitors and angiotensin II type 1 receptor blockers, and β-adrenoceptor blockers may have improved survival and reduced hospitalisation from exacerbations. Progress in basic and translational research has led to a better understanding of pharmacological mechanisms that may explain the effects of these drugs on COPD and some small clinical trial activity is beginning to generate promising results.