Montelukast reduces airway eosinophilic inflammation in asthma: a randomized, controlled trial

Mucus plugs in the airways of asthmatic subjects and smoking status

BACKGROUND

Mucus plugs have been described in the airways of asthmatic subjects, particularly those with associated with type 2 inflammation and sputum eosinophilia. In the current study we addressed the question of whether smoking, neutrophilic inflammation and airway dimensions affected the prevalence of mucus plugs.

METHODS

In a cohort of moderate to severe asthmatics (n = 50), including a group of ex-smokers and current smokers, the prevalence of mucus plugs was quantified using a semi-quantitative score based on thoracic computerized tomography. The relationships between mucus score, sputum inflammatory profile and airway architecture were tested according to patient's smoking status.

RESULTS

Among the asthmatics (37% former or active smokers), 74% had at least one mucus plug. The median score was 3 and was unrelated to smoking status. A significant but weak correlation was found between mucus score, FEV1 and FEV1/FVC. Mucus score was significantly correlated with sputum eosinophils. Among former and active smokers, mucus score was correlated with sputum neutrophils. Mucus score was positively associated with FeNO in non-smoking subjects. The lumen dimensions of the main and lobar bronchi were significantly inversely correlated with mucus score.

CONCLUSION

Airway mucus plugs could define an asthma phenotype with altered airway architecture and can occur in asthmatic subjects with either neutrophilic or eosinophilic sputum according to their smoking status.

Impact of Anti-IL5 Therapies on Patients with Severe Uncontrolled Asthma and Possible Predictive Biomarkers of Response: A Real-Life Study

Severe Uncontrolled Asthma (SUA) counts for more than 25% of cases of severe asthma. The main factors that impair the quality of life of these patients are high doses of oral corticosteroids, the presence of exacerbations, and reduced lung function. The objective of this study was to evaluate, in real life, the clinical improvement of patients with SUA treated with anti-interleukin 5 (IL5) therapies: mepolizumab and benralizumab, together with the search for biomarkers associated with the response. We conducted a retrospective observational cohort study that included patients with severe uncontrolled eosinophilic asthma in a tertiary hospital receiving biological therapies. Three types of response were evaluated: improvement in lung function, reduction in exacerbations, and decrease in the use of oral corticosteroids. After 12 months of treatment, significant reductions were found in the number of exacerbations, the use of oral corticosteroids, and blood eosinophil levels for both biological therapies (p < 0.001). Lung function improved, achieving a significant improvement in %FEV1 (p < 0.001), as well as asthma control, with a significant increase in asthma control test (ACT) scores in both therapies. The markers associated with the corticosteroid-saving effect were the low doses of oral corticosteroids and absence of exacerbations for mepolizumab, and higher blood eosinophilia, absence of chronic obstructive pulmonary disease (COPD), and reduction in oral corticosteroid cycles for benralizumab. The greatest improvement in lung function in both therapies was linked to lower previous FEV1 levels and absence of other respiratory diseases. The reduction in exacerbations was associated with absence of exacerbations the previous year for mepolizumab and never smokers for benralizumab. The results of this real-life study confirm the clinical benefit obtained after the introduction of an anti-IL5 biological therapy and the possible predictive biomarkers of response to treatment.

Multisystem Inflammatory Syndrome and Autoimmune Diseases Following COVID-19: Molecular Mechanisms and Therapeutic Opportunities

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2), has led to huge concern worldwide. Some SARS-CoV-2 infected patients may experience post–COVID-19 complications such as multisystem inflammatory syndrome, defined by symptoms including fever and elevated inflammatory markers (such as elevation of C reactive protein (CRP), erythrocyte sedimentation rate, fibrinogen, procalcitonin test, D-dimer, ferritin, lactate dehydrogenase or IL-6, presence of neutrophilia, lymphopenia, decreased albumin, and multiple organ dysfunction). Post–COVID-19 complications may also manifest as autoimmune diseases such as Guillain-Barré syndrome and systemic lupus erythematosus. Signaling disorders, increased inflammatory cytokines secretion, corticosteroid use to treat COVID-19 patients, or impaired immune responses are suggested causes of autoimmune diseases in these patients. In this review, we discuss the molecular and pathophysiological mechanisms and therapeutic opportunities for multisystem inflammatory syndrome and autoimmune diseases following SARS-CoV-2 infection with the aim to provide a clear view for health care providers and researchers.

Trained immunity in type 2 immune responses

Immunological memory of innate immune cells, also termed "trained immunity", allows for cross-protection against distinct pathogens, but may also drive chronic inflammation. Recent studies have shown that memory responses associated with type 2 immunity do not solely rely on adaptive immune cells, such as T- and B cells, but also involve the innate immune system and epithelial cells. Memory responses have been described for monocytes, macrophages and airway epithelial cells of asthmatic patients as well as for macrophages and group 2 innate lymphoid cells (ILC2) from allergen-sensitized or helminth-infected mice. The metabolic and epigenetic mechanisms that mediate allergen- or helminth-induced reprogramming of innate immune cells are only beginning to be uncovered. Trained immunity has been implicated in helminth-driven immune regulation and allergen-specific immunotherapy, suggesting its exploitation in future therapies. Here, we discuss recent advances and key remaining questions regarding the mechanisms and functions of trained type 2 immunity in infection and inflammation.

Effect of montelukast therapy on clinical course, pulmonary function, and mortality in patients with COVID-19

The inflammatory/anti‐inflammatory balance has an important role in the clinical course of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) (coronavirus disease [COVID‐19]) infection, which has affected over 200 million people since it first appeared in China in December 2019. This study aimed to determine the effectiveness of montelukast, which has known anti‐inflammatory and bronchodilatory effects, in these patients. The prospective randomized controlled study included 180 patients who were hospitalized in the infectious diseases department of our hospital between May and July 2021 and were diagnosed with the delta variant of SARS‐CoV‐2 by real‐time polymerase chain reaction of nasopharyngeal swabs. The patients were divided into three groups and received only standard treatment according to national guidelines (Group 1) or standard treatment plus 10 mg/day montelukast (Group 2) or 20 mg/day montelukast (Group 3). Laboratory parameters and pulmonary function tests (PFTs) at admission and on Day 5 of treatment were compared. Comparison of laboratory parameters on Day 5 showed that Groups 2 and 3 had significantly lower levels of lactate dehydrogenase, fibrinogen, D‐dimer, C‐reactive protein, and procalcitonin compared with Group 1 (p = 0.04, 0.002, 0.05, 0.03, and 0.04, respectively). In the comparison between Groups 2 and 3, only fibrinogen was significantly lower in Group 3 (p = 0.02). PFT results did not differ between the groups at admission, while on Day 5, only Group 3 showed significant improvements in forced expiratory volume in 1 s, forced vital capacity, and peak expiratory flow 25–75 compared with admission (p = 0.001 for all). Montelukast may be beneficial in COVID‐19 patients to maintain the inflammatory/anti‐inflammatory balance, prevent respiratory failure through its bronchodilator activity, and reduce mortality.

The study included 180 participants who were divided into three groups: Group 1 (n = 60) received standard treatment in accordance with our national COVID‐19 diagnosis and treatment guide, Group 2 (n = 60) received 10 mg/day oral montelukast in addition to standard treatment, and Group 3 (n = 60) received 20 mg/day oral montelukast in addition to standard treatment.

We aimed to investigate the effect of treatment with varying doses of montelukast as an adjunct to standard antiviral therapy on pulmonary function tests and clinical courses in patients with COVID‐19.

Novel pharmacological therapies for the treatment of bronchial asthma

Asthma has long been recognised as a chronic inflammatory disease of the airways, often in response to inhaled allergens prompting inappropriate activation of the immune response. involving a range of cells including mast cells, Th2 lymphocytes and eosinophils and a wide range of inflammatory mediators. First-line therapy for treatment of persistent asthma involves the use of inhaled corticosteroids (ICS) in combination with inhaled β2-agonists enabling both the control of the underlying airways inflammation and a reduction of airway hyperresponsiveness. However, many patients remain symptomatic despite high-dose therapy. There is therefore a continued unmet clinical need to develop specifically new anti-inflammatory therapies for patients with asthma, either as an add-on therapy to ICS or as replacement monotherapies. The success of fixed dose combination inhalers containing both a bronchodilator and an anti-inflammatory drug has also led to the development of "bifunctional" drugs which are molecules specifically designed to have two distinct pharmacological actions based on distinct pharmacophores. In this review we will discuss these different pharmacological approaches under development for the treatment of bronchial asthma and the available pre-clinical and clinical data.

Therapeutic targets in lung tissue remodelling and fibrosis

Structural changes involving tissue remodelling and fibrosis are major features of many pulmonary diseases, including asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF). Abnormal deposition of extracellular matrix (ECM) proteins is a key factor in the development of tissue remodelling that results in symptoms and impaired lung function in these diseases. Tissue remodelling in the lungs is complex and differs between compartments. Some pathways are common but tissue remodelling around the airways and in the parenchyma have different morphologies. Hence it is critical to evaluate both common fibrotic pathways and those that are specific to different compartments; thereby expanding the understanding of the pathogenesis of fibrosis and remodelling in the airways and parenchyma in asthma, COPD and IPF with a view to developing therapeutic strategies for each. Here we review the current understanding of remodelling features and underlying mechanisms in these major respiratory diseases. The differences and similarities of remodelling are used to highlight potential common therapeutic targets and strategies. One central pathway in remodelling processes involves transforming growth factor (TGF)-β induced fibroblast activation and myofibroblast differentiation that increases ECM production. The current treatments and clinical trials targeting remodelling are described, as well as potential future directions. These endeavours are indicative of the renewed effort and optimism for drug discovery targeting tissue remodelling and fibrosis.

Lipid metabolism in asthma: Immune regulation and potential therapeutic target

Asthma is a chronic inflammatory disease of the lungs that poses a considerable health and socioeconomic burden. Several risk factors work synergistically to affect the progression of asthma. Lipid metabolism, especially in distinct cells such as T cells, macrophages, granulocytes, and non-immune cells, plays an essential role in the pathogenesis of asthma, as lipids are potent signaling molecules that regulate a multitude of cellular response. In this review, we focused on the metabolic pathways of lipid molecules, especially fatty acids and their derivatives, and summarized their roles in various cells during the pathogenesis of asthma along with the current pharmacological agents targeting lipid metabolism.

Exhaled breath analysis in disease detection

Investigating the use of exhaled breath analysis to diagnose and monitor different diseases has attracted much interest in recent years. This review introduces conventionally used methods and some emerging technologies aimed at breath analysis and their relevance to lung disease, airway inflammation, gastrointestinal disorders, metabolic disorders and kidney diseases. One section correlates breath components and specific diseases, whereas the other discusses some unique ideas, strategies, and devices to analyze exhaled breath for the diagnosis of some common diseases. This review aims to briefly introduce the potential application of exhaled breath analysis for the diagnosis and screening of various diseases, thereby providing a new avenue for the detection of non-invasive diseases.

Current perspective on eicosanoids in asthma and allergic diseases: EAACI Task Force consensus report, part I

Eicosanoids are biologically active lipid mediators, comprising prostaglandins, leukotrienes, thromboxanes, and lipoxins, involved in several pathophysiological processes relevant to asthma, allergies, and allied diseases. Prostaglandins and leukotrienes are the most studied eicosanoids and established inducers of airway pathophysiology including bronchoconstriction and airway inflammation. Drugs inhibiting the synthesis of lipid mediators or their effects, such as leukotriene synthesis inhibitors, leukotriene receptors antagonists, and more recently prostaglandin D₂ receptor antagonists, have been shown to modulate features of asthma and allergic diseases. This review, produced by an European Academy of Allergy and Clinical Immunology (EAACI) task force, highlights our current understanding of eicosanoid biology and its role in mediating human pathology, with a focus on new findings relevant for clinical practice, development of novel therapeutics, and future research opportunities.

Targeting neutrophils in asthma: A therapeutic opportunity?

Suppression of airway inflammation with inhaled corticosteroids has been the key therapeutic approach for asthma for many years. Identification of inflammatory phenotypes in asthma has moreover led to important breakthroughs, e.g. with specific targeting of the IL-5 pathway as add-on treatment in difficult-to-treat eosinophilic asthma. However, the impact of interfering with the neutrophilic component in asthma is less documented and understood. This review provides an overview of established and recent insights with regard to the role of neutrophils in asthma, focusing on research in humans. We will describe the main drivers of neutrophilic responses in asthma, the heterogeneity in neutrophils and how they could contribute to asthma pathogenesis. Moreover we will describe findings from clinical trials, in which neutrophilic inflammation was targeted. It is clear that neutrophils are important actors in asthma development and play a role in exacerbations. However, more research is required to fully understand how modulation of neutrophil activity could lead to a significant benefit in asthma patients with airway neutrophilia.

Colchicine, Aspirin, and Montelukast - A Case of Successful Combined Pharmacotherapy for Adult Multisystem Inflammatory Syndrome in COVID-19

Since the beginning of the COVID-19 pandemic, many therapeutic strategies have been tried, with mixed results, to prevent and treat adult multisystem inflammatory syndrome in COVID-19 (AMIS-COVID-19). The reason behind this may the complex web of highly intertwined pathophysiologic mechanisms involved in the SARS-CoV-2 infection and the corresponding human systemic response, leading to end-organ damage, disability, and death. Colchicine, high-dose aspirin, and montelukast are being investigated currently as potential modulators of AMIS-COVID-19 in patients who fail to improve with traditional therapeutic approaches. Here, we present a patient who presented with high fevers, extreme fatigue and dyspnea, and ongoing deterioration. As part of our clinical approach, we used the simultaneous combination of the three agents listed above, capitalizing on their different respective mechanisms of action against AMIS-COVID-19. Following the initiation of therapy, the patient showed symptomatic improvement within 24 h, with the ability to return to daily activities after 72 h of continued triple-agent approach. Based on this experience, we have reviewed the immunomodulatory basis of this regimen, including potential avenues in which it may prevent the development of cytokine release syndrome (CRS) and its clinical manifestation, AMIS-COVID-19. By blocking the early stages of an inflammatory response, via diverse mechanistic pathways, the regimen in question may prove effective in halting the escalation of CRS and AMIS-COVID-19 in acutely symptomatic, nonimproving COVID-19 patients.

Current state and future prospect of the therapeutic strategy targeting cysteinyl leukotriene metabolism in asthma

Asthma is an allergic disorder with dominant type 2 airway inflammation, and its prevalence is increasing worldwide. Inhalation of corticosteroids is the primary treatment for asthma along with add-on drugs, including long-acting β2 agonists and/or cysteinyl leukotriene (cys-LT) receptor antagonists, in patients with poorly controlled asthma. Cys-LTs are composed of leukotriene C4 (LTC₄), LTD₄, and LTE₄, which are enzymatically metabolized from arachidonic acid. These molecules act as inflammatory mediators through different types of high-affinity receptors, namely, CysLT₁, CysLT₂, and CysLT₃ (also named as GPR99). CysLT₁ antagonists possessing anti-inflammatory and bronchodilatory effects can be orally administered to patients with asthma. Recently, molecular biology-based studies have revealed the mechanism of inflammatory responses via other receptors, such as CysLT₂ and CysLT₃, as well as the importance of upstream inflammatory regulators, including type 2 cytokines (e.g., interleukins 4 and 5), in controlling cys-LT metabolism. These findings indicate the therapeutic potential of pharmacological agents targeting cys-LT metabolism-related receptors and enzymes, and antibody drugs neutralizing or antagonizing type 2 cytokines. This review focuses on the current state and future prospect of the therapeutic strategy targeting cys-LT metabolism.

Involvement and Possible Role of Eosinophils in Asthma Exacerbation

Eosinophils are involved in the development of asthma exacerbation. Recent studies have suggested that sputum and blood eosinophil counts are important factors for predicting asthma exacerbation. In severe eosinophilic asthma, anti-interleukin (IL)-5 monoclonal antibody decreases blood eosinophil count and asthma exacerbation frequency. However, even in the absence of IL-5, eosinophilic airway inflammation can be sufficiently maintained by the T helper (Th) 2 network, which comprises a cascade of vascular cell adhesion molecule-1/CC chemokines/eosinophil growth factors, including granulocyte-macrophage colony-stimulating factor (GM-CSF). Periostin, an extracellular matrix protein and a biomarker of the Th2 immune response in asthma, directly activates eosinophils in vitro. A major cause of asthma exacerbation is viral infection, especially rhinovirus (RV) infection. The expression of intercellular adhesion molecule (ICAM)-1, a cellular receptor for the majority of RVs, on epithelial cells is increased after RV infection, and adhesion of eosinophils to ICAM-1 can upregulate the functions of eosinophils. The expressions of cysteinyl leukotrienes (cysLTs) and CXCL10 are upregulated in virus-induced asthma. CysLTs can directly provoke eosinophilic infiltration in vivo and activate eosinophils in vitro. Furthermore, eosinophils express the CXC chemokine receptor 3, and CXCL10 activates eosinophils in vitro. Both eosinophils and neutrophils contribute to the development of severe asthma or asthma exacerbation. IL-8, which is an important chemoattractant for neutrophils, is upregulated in some cases of severe asthma. Lipopolysaccharide (LPS), which induces IL-8 from epithelial cells, is also increased in the lower airways of corticosteroid-resistant asthma. IL-8 or LPS-stimulated neutrophils increase the transbasement membrane migration of eosinophils, even in the absence of chemoattractants for eosinophils. Therefore, eosinophils are likely to contribute to the development of asthma exacerbation through several mechanisms, including activation by Th2 cytokines, such as IL-5 or GM-CSF or by virus infection-related proteins, such as CXCL10, and interaction with other cells, such as neutrophils.

Comparison between montelukast and tiotropium as add-on therapy to inhaled corticosteroids plus a long-acting β2-agonist in for patients with asthma

Objective: Asthma often remains uncontrolled despite treatment with inhaled corticosteroids (ICS) alone or with ICS plus a long-acting β₂-agonist (LABA). The recommended alternative is the addition of either montelukast or tiotropium. The aim of this study was to compare the effects of montelukast and tiotropium on airway inflammation and remodeling in persistent asthma. Methods: Eighty-seven patients with asthma were treated with budesonide and formoterol (640/18 μg); then, the patients were randomly allocated to three groups to receive oral montelukast (10 mg/day), inhaled tiotropium (5 μg/day), or no add-on to the maintenance therapy for 48 weeks. Fractional exhaled nitric oxide (FeNO) and pulmonary function were measured, and quantitative computed tomography was performed. Results: Compared to the maintenance therapy, add-on montelukast significantly decreased FeNO (p < 0.05) and improved airflow obstruction (p < 0.05), whereas airway dimensions remained unchanged. Changes in FeNO were significantly correlated with changes in FEV₁ (r = -0.71, p < 0.001). In contrast, the addition of tiotropium significantly decreased airway wall area corrected for body surface area (WA/BSA) (p < 0.05), decreased wall thickness (T/√BSA) (p < 0.05) and improved airflow obstruction (p < 0.05) with no change in FeNO. Changes in WA/BSA and T/√BSA were significantly correlated with the change in percentage predicted FEV₁ (r = -0.84, p < 0.001 and r = -0.59, p < 0.01, respectively). Conclusions:Adding either montelukast or tiotropium to ICS/LABA may provide additive benefits with respect to the pulmonary function and airway inflammation or remodeling in patients with asthma.

Regulation of Eosinophil and Group 2 Innate Lymphoid Cell Trafficking in Asthma

Asthma is an inflammatory disease usually characterized by increased Type 2 cytokines and by an infiltration of eosinophils to the airways. While the production of Type 2 cytokines has been associated with T_H2 lymphocytes, increasing evidence indicates that group 2 innate lymphoid cells (ILC2) play an important role in the production of the Type 2 cytokines interleukin (IL)-5 and IL-13, which likely amplifies the recruitment of eosinophils from the blood to the airways. In that regard, recent asthma treatments have been focusing on blocking Type 2 cytokines, notably IL-4, IL-5, and IL-13. These treatments mainly result in decreased blood or sputum eosinophil counts as well as decreased asthma symptoms. This supports that therapies blocking eosinophil recruitment and activation are valuable tools in the management of asthma and its severity. Herein, we review the mechanisms involved in eosinophil and ILC2 recruitment to the airways, with an emphasis on eotaxins, other chemokines as well as their receptors. We also discuss the involvement of other chemoattractants, notably the bioactive lipids 5-oxo-eicosatetraenoic acid, prostaglandin D₂, and 2-arachidonoyl-glycerol. Given that eosinophil biology differs between human and mice, we also highlight and discuss their responsiveness toward the different eosinophil chemoattractants.

Cysteinyl Leukotrienes in Eosinophil Biology: Functional Roles and Therapeutic Perspectives in Eosinophilic Disorders

Cysteinyl leukotrienes (cysLTs), LTC4, and its extracellular metabolites, LTD4 and LTE4, have varied and multiple roles in mediating eosinophilic disorders including host defense against parasitic helminthes and allergic inflammation, especially in the lung and in asthma. CysLTs are known to act through at least 2 receptors termed cysLT1 receptor (CysLT1R) and cysLT2 receptor (CysLT2R). Eosinophils contain a dominant population of cytoplasmic crystalloid granules that store various preformed proteins. Human eosinophils are sources of cysLTs and are known to express the two known cysLTs receptors (CysLTRs). CysLTs can have varied functions on eosinophils, ranging from intracrine regulators of secretion of granule-derived proteins to paracrine/autocrine roles in eosinophil chemotaxis, differentiation, and survival. Lately, it has been recognized the expression of CysLTRs in the membranes of eosinophil granules. Moreover, cysLTs have been shown to evoke secretion from isolated cell-free eosinophil granules operating through their receptors expressed on granule membranes. In this work, we review the functional roles of cysLTs in eosinophil biology. We review cysLTs biosynthesis, their receptors, and argue the intracrine and paracrine/autocrine responses induced by cysLTs in eosinophils and in isolated free extracellular eosinophil granules. We also examine and speculate on the therapeutic relevance of targeting CysLTRs in the treatment of eosinophilic disorders.

Race is associated with differences in airway inflammation in patients with asthma

BACKGROUND

African American subjects have a greater burden from asthma compared with white subjects. Whether the pattern of airway inflammation differs between African American and white subjects is unclear.

OBJECTIVE

We sought to compare sputum airway inflammatory phenotypes of African American and white subjects treated or not with inhaled corticosteroids (ICSs; ICS+ and ICS-, respectively).

METHODS

We performed a secondary analysis of self-identified African American and white subjects with asthma enrolled in clinical trials conducted by the National Heart, Lung, and Blood Institute-sponsored Asthma Clinical Research Network and AsthmaNet. Demographics, clinical characteristics, and sputum cytology after sputum induction were examined. We used a sputum eosinophil 2% cut point to define subjects with either an eosinophilic (≥2%) or noneosinophilic (<2%) inflammatory phenotype.

RESULTS

Among 1018 participants, African American subjects (n = 264) had a lower FEV1 percent predicted (80% vs 85%, P < .01), greater total IgE levels (197 vs 120 IU/mL, P < .01), and a greater proportion with uncontrolled asthma (43% vs 28%, P < .01) compared with white subjects (n = 754). There were 922 subjects in the ICS+ group (248 African American and 674 white subjects) and 298 subjects in the ICS- group (49 African American and 249 white subjects). Eosinophilic airway inflammation was not significantly different between African American and white subjects in either group (percentage with eosinophilic phenotype: ICS+ group: 19% vs 16%, P = .28; ICS- group: 39% vs 35%, P = .65; respectively). However, when adjusted for confounding factors, African American subjects were more likely to exhibit eosinophilic airway inflammation than white subjects in the ICS+ group (odds ratio, 1.58; 95% CI, 1.01-2.48; P = .046) but not in the ICS- group (P = .984).

CONCLUSION

African American subjects exhibit greater eosinophilic airway inflammation, which might explain the greater asthma burden in this population.

The selective cysteinyl leukotriene receptor 1 (CysLT1R) antagonist montelukast regulates extracellular matrix remodeling

Scar formation after filtration surgery of glaucoma is mainly caused by excessive synthesis of new extracellular matrix (ECM) and contraction of subconjunctival tissue mediated by human Tenon fibroblasts (HTFs) and the transforming growth factor (TGF-β1). Montelukast, a potent and specific cysteinyl leukotriene receptor 1 (cysLT1R) antagonist, is a licensed drug clinically used for the treatment of bronchial asthma. In this study, we investigated the effects of montelukast on the contractility of HTFs cultured in a three-dimensional collagen gel. We found that cysLT1R was expressed in HTFs. Interestingly, the expression of cysLT1R was increased in response to TGF-β1 in a dose dependent manner, suggesting its potential role in TGF-β1 induced fibrosis. Importantly, we found that montelukast inhibited TGF-β1-induced collagen gel contraction mediated by HTFs in a concentration- and time-dependent manner. In addition, TGF-β1-induced expression of MMP-1 and MMP-3, generation of fibronectin and type I collagen production, focal adhesion kinase (FAK) and paxillin phosphorylation in HTFs were also ameliorated by montelukast in a dose dependent manner. These results suggested that montelukast might provide therapeutic possibilities for inhibition of scar formation after such surgery.

A dual CysLT1/2 antagonist attenuates allergen-induced airway responses in subjects with mild allergic asthma

BACKGROUND

The cysteinyl leukotrienes (cysLTs) play a key role in the pathophysiology of asthma. In addition to functioning as potent bronchoconstrictors, cysLTs contribute to airway inflammation through eosinophil and neutrophil chemotaxis, plasma exudation, and mucus secretion. We tested the activity of the dual cysLT_1/2 antagonist, ONO-6950, against allergen-induced airway responses.

METHODS

Subjects with documented allergen-induced early (EAR) and late asthmatic response (LAR) were randomized in a three-way crossover study to receive ONO-6950 (200 mg) or montelukast (10 mg) or placebo q.d. on days 1-8 of the three treatment periods. Allergen was inhaled on day 7 two hours postdose, and forced expiratory volume in 1 s (FEV₁ ) was measured for 7 h following challenge. Sputum eosinophils and airway hyperresponsiveness were measured before and after allergen challenge. The primary outcome was the effect of ONO-6950 vs placebo on the EAR and LAR.

RESULTS

Twenty-five nonsmoking subjects with mild allergic asthma were enrolled and 20 subjects completed all three treatment periods per protocol. ONO-6950 was well tolerated. Compared to placebo, ONO-6950 significantly attenuated the maximum % fall in FEV₁ and area under the %FEV₁ /time curve during the EAR and LAR asthmatic responses (P < 0.05) and allergen-induced sputum eosinophils. There were no significant differences between ONO-6950 and montelukast.

CONCLUSIONS

Attenuation of EAR, LAR, and airway inflammation is consistent with cysLT₁ blockade. Whether dual cysLT_1/2 antagonism offers additional benefit for treatment of asthma requires further study.

Bronchoprotection and bronchorelaxation in asthma: New targets, and new ways to target the old ones

Despite over 50years of inhaled beta-agonists and corticosteroids as the default management or rescue drugs for asthma, recent research suggests that new therapeutic options are likely to emerge. This belief stems from both an improved understanding of what causes and regulates airway smooth muscle (ASM) contraction, and the identification of new targets whose inhibition or activation can relax ASM. In this review we discuss the recent findings that provide new insight into ASM contractile regulation, a revolution in pharmacology that identifies new ways to "tune" G protein-coupled receptors to improve therapeutic efficacy, and the discovery of several novel targets/approaches capable of effecting bronchoprotection or bronchodilation.

Patient stratification and the unmet need in asthma

Asthma is often described as an inflammatory disease of the lungs and in most patients symptomatic treatment with bronchodilators or inhaled corticosteroids is sufficient to control disease. Unfortunately there are a proportion of patients who fail to achieve control despite treatment with the best current treatment. These severe asthma patients have been considered a homogeneous group of patients that represent the unmet therapeutic need in asthma. Many novel therapies have been tested in unselected asthma patients and the effects have often been disappointing, particularly for the highly specific monoclonal antibody-based drugs such as anti-IL-13 and anti-IL-5. More recently, it has become clear that asthma is a syndrome with many different disease drivers. Clinical trials of anti-IL-13 and anti-IL-5 have focused on biomarker-defined patient groups and these trials have driven the clinical progression of these drugs. Work on asthma phenotyping indicates that there is a group of asthma patients where T helper cell type 2 (Th2) cytokines and inflammation predominate and these type 2 high (T2-high) patients can be defined by biomarkers and response to therapies targeting this type of immunity, including anti-IL-5 and anti-IL-13. However, there is still a subset of T2-low patients that do not respond to these new therapies. This T2-low group will represent the new unmet medical need now that the T2-high-targeting therapies have made it to the market. This review will examine the current thinking on patient stratification in asthma and the identification of the T2-high subset. It will also look at the T2-low patients and examine what may be the drivers of disease in these patients.

Inflammatory markers as exacerbation risk factors after asthma therapy switch from inhaled steroids to montelukast

BACKGROUND

Asthma guidelines allow anti-leukotriene medications to be used as an alternative to inhaled corticosteroids (ICS) in second-step intensity therapy. The aim of the study was to analyze the risk factors of exacerbations, particularly inflammatory markers, during the 12-month period following therapy reduction from an ICS to montelukast in young patients with mild asthma.

METHODS

A total of 84 patients (aged 7-18 years old) with mild asthma controlled by low-dose ICS, had their treatment switched to montelukast. Exhaled nitric oxide (eNO), sputum eosinophils (sEos), and bronchial hyperreactivity (BHR) were assessed at the beginning and then every three months throughout the one-year period. The patients with asthma exacerbations (first severe or third mild) were discontinued from the study.

RESULTS

Over the study period, 22 patients (26%) discontinued montelukast due to asthma exacerbations. An increased risk of exacerbations was noted among patients with initial sEos above 2.5% (relative risk, RR 36.6; 95% CI: 7.1-189.3; p < 0.001), as well as those with augmented BHR (RR 9.5; 2.8-31.6; p < 0.001), or eNO greater than 20 ppb (RR 3.7; 95% CI: 1.3-10.7; p = 0.013). An increase in BHR and eNO was observed during the last visit before exclusion.

CONCLUSIONS

After switching treatment from a low-dose ICS, montelukast maintained control of asthma symptoms in 75% of patients. High sEos before the treatment change was the strongest exacerbation risk factor. In patients with asthma controlled by low-dose ICS and low inflammatory markers, treatment could be safely switched to montelukast.

Montelukast medicines of today and tomorrow: from molecular pharmaceutics to technological formulations

Montelukast sodium is a leukotriene antagonist of growing interest as an alternative therapy for asthma across different age groups due to its bronchoprotective, anti-inflammatory and anti-allergic properties. Currently, montelukast is commercialized only in oral solid dosage forms, which are the favorite of adult patients but may pose challenges in administration to children of young age or patients suffering from dysphagia. This review presents a comprehensive revision of scientific reports and patents on emerging strategies for the delivery of montelukast. A common ground to these reports is the pursue of an enhanced montelukast performance, by increasing its bioavailability and physico-chemical stability. A wide variety of strategies can be found, from the formation of supramolecular adducts with cyclodextrins to encapsulation in nanoparticles and liposomes. The new dosage forms for montelukast are designed for non-enteric absorption, some for absorption in the oral cavity and another two being for local action in the nasal mucosa or in the pulmonary epithelium. The review describes the emerging delivery strategies to circumvent the current limitations to the use of montelukast that are expected to ultimately lead to the development of more patient-compliant dosage forms.

Eosinophilic airway inflammation: role in asthma and chronic obstructive pulmonary disease

The chronic lung diseases, asthma and chronic obstructive pulmonary disease (COPD), are common affecting over 500 million people worldwide and causing substantial morbidity and mortality. Asthma is typically associated with Th2-mediated eosinophilic airway inflammation, in contrast to neutrophilic inflammation observed commonly in COPD. However, there is increasing evidence that the eosinophil might play an important role in 10-40% of patients with COPD. Consistently in both asthma and COPD a sputum eosinophilia is associated with a good response to corticosteroid therapy and tailored strategies aimed to normalize sputum eosinophils reduce exacerbation frequency and severity. Advances in our understanding of the multistep paradigm of eosinophil recruitment to the airway, and the consequence of eosinophilic inflammation, has led to the development of new therapies to target these molecular pathways. In this article we discuss the mechanisms of eosinophilic trafficking, the tools to assess eosinophilic airway inflammation in asthma and COPD during stable disease and exacerbations and review current and novel anti-eosinophilic treatments.

Leukotriene-receptor antagonists versus placebo in the treatment of asthma in adults and adolescents: a systematic review and meta-analysis

BACKGROUND

Leukotriene-receptor antagonists (LTRAs) are recommended as an alternative treatment in patients with mild asthma, but their effect compared with placebo is unclear.

PURPOSE

To determine the benefits and harms of LTRAs as monotherapy or in combination with inhaled corticosteroids compared with placebo in adults and adolescents with asthma.

DATA SOURCES

MEDLINE and the Cochrane Central Register of Controlled Trials from inception through June 2015.

STUDY SELECTION

Peer-reviewed, English-language, randomized, controlled trials in patients with asthma that reported the effect of LTRAs versus placebo on measures of asthma control.

DATA EXTRACTION

Three researchers extracted data on study population, interventions, outcome measures, and adverse events. One researcher assessed risk of bias.

DATA SYNTHESIS

Of the 2008 abstracts that were screened, 50 trials met eligibility criteria. Random-effects meta-analyses of 6 trials of LTRA monotherapy showed that LTRAs reduced the risk for an exacerbation (summary risk ratio [RR], 0.60 [95% CI, 0.44 to 0.81]). In 4 trials of LTRAs as add-on therapy to inhaled corticosteroids, the summary RR for exacerbation was 0.80 (CI, 0.60 to 1.07). Leukotriene-receptor antagonists either as monotherapy or as add-on therapy to inhaled corticosteroids increased FEV1, whereas FEV1 percentage of predicted values was improved only in trials of LTRA monotherapy. Adverse event rates were similar in the intervention and comparator groups.

LIMITATION

Variation in definitions and reporting of outcomes, high risk of bias in some studies, heterogeneity of findings, possible selective outcome reporting bias, and inability to assess the effect of asthma severity on summary estimates.

CONCLUSION

Leukotriene-receptor antagonists as monotherapy improved asthma control compared with placebo, but which patients are most likely to respond to treatment with LTRAs remains unclear.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Mechanism of glutamine inhibition of cytosolic phospholipase a2 (cPLA2 ): Evidence of physical interaction between glutamine-Induced mitogen-activated protein kinase phosphatase-1 and cPLA2

Non-essential amino acid L-glutamine (Gln) possesses anti-inflammatory activity via deactivating cytosolic phospholipase A2 (cPLA2 ). We showed previously that Gln deactivated cPLA2 indirectly via dephosphorylating p38 mitogen-activated protein kinase (MAPK), the major kinase for cPLA2 phosphorylation, through inducing MAPK phosphatase-1 (MKP-1). In this study, we investigated the precise mechanism underlying Gln deactivation of cPLA2 . In lipopolysaccharide (LPS)-treated mice, Gln injection resulted in dephosphorylation of phosphorylated cPLA2 (p-cPLA2 ), which coincided with rapid Gln induction of MKP-1. MKP-1 small interfering RNA (siRNA) abrogated the ability of Gln to induce MKP-1 as well as the dephosphorylation of cPLA2 . Co-immunoprecipitation and in-situ proximity ligation assay revealed a physical interaction between MKP-1 and p-cPLA2 . In a murine model of allergic asthma, we also demonstrated the physical interaction between MKP-1 and p-cPLA2 . Furthermore, Gln suppressed various allergic asthma phenotypes, such as neutrophil and eosinophil recruitments into the airway, airway levels of T helper type 2 (Th2) cytokines [interleukin (IL)-4, IL-5 and IL-13], airway hyperresponsiveness, mucin production and metabolites (leukotriene B4 and platelet-activating factor) through inhibiting cPLA2 in a MKP-1-dependent manner. These data suggest that MKP-1 uses cPLA2 , in addition to p38, as a substrate, which further potentiates the anti-inflammatory action of Gln.

Addition to inhaled corticosteroids of leukotriene receptor antagonists versus theophylline for symptomatic asthma: a meta-analysis

BACKGROUND

Inhaled corticosteroids (ICSs) are widely used in combination with second controller medications in the management of asthma in adults and children. There lacks a systematic comparison between addition of leukotriene receptor antagonists (LTRAs) and theophylline to ICS. The purpose of this meta-analysis was to evaluate the difference of the efficacy and safety profile of adding either LTRAs or theophylline to ICS in adults and children with symptomatic asthma.

METHODS

Randomised controlled trials (RCTs) published prior to November 2014 were acquired through systematically searching and selected based on the established inclusion criteria for publications. The data extracted from the included studies were further analyzed by a meta-analysis.

RESULTS

We included eight RCTs, of which six recruited adults and two recruited children aged 5 to 14 years. The primary outcomes were changes in lung function from baseline, including forced expiratory volume in the first second (FEV1) and peak expiratory flow (PEF). Overall, addition of LTRAs led to significantly better morning PEF {mean difference (MD) 16.94 [95% confidence interval (CI): 11.49-22.39] L/min, P<0.01} and FEV1 [MD 0.09 (95% CI: 0.03-0.15) L, P=0.005] as compared to addition of theophylline. There were no differences between the two treatments in terms of evening PEF, adverse events, rescue medication use and asthma exacerbation.

CONCLUSIONS

The combination of LTRA and ICS leads to modestly greater improvement in lung function than the combination of theophylline and ICS in the treatment of symptomatic asthma. Long-term trials are required to assess the efficacy and safety of these two therapies.

A review on airway biomarkers: exposure, effect and susceptibility

Current research in pulmonology requires the use of biomarkers to investigate airway exposure and diseases, for both diagnostic and prognostic purposes. The traditional approach based on invasive approaches (lung lavages and biopsies) can now be replaced, at least in part, through the use of non invasively collected specimens (sputum and breath), in which biomarkers of exposure, effect and susceptibility can be searched. The discovery of specific lung-related proteins, which can spill over in blood or excreted in urine, further enhanced the spectrum of airway specific biomarkers to be studied. The recent introduction of high-performance 'omic' technologies - genomics, proteomics and metabolomics, and the rate at which biomarker candidates are being discovered, will permit the use of a combination of biomarkers for a more precise selection of patient with different outcomes and responses to therapies. The aim of this review is to critically evaluate the use of airway biomarkers in the context of research and clinical practice.

Leukocyte chemoattractant receptors in human disease pathogenesis

Combinations of leukocyte attractant ligands and cognate heptahelical receptors specify the systemic recruitment of circulating cells by triggering integrin-dependent adhesion to endothelial cells, supporting extravasation, and directing specific intratissue localization via gradient-driven chemotaxis. Chemoattractant receptors also control leukocyte egress from lymphoid organs and peripheral tissues. In this article, we summarize the fundamental mechanics of leukocyte trafficking, from the evolution of multistep models of leukocyte recruitment and navigation to the regulation of chemoattractant availability and function by atypical heptahelical receptors. To provide a more complete picture of the migratory circuits involved in leukocyte trafficking, we integrate a number of nonchemokine chemoattractant receptors into our discussion. Leukocyte chemoattractant receptors play key roles in the pathogenesis of autoimmune diseases, allergy, inflammatory disorders, and cancer. We review recent advances in our understanding of chemoattractant receptors in disease pathogenesis, with a focus on genome-wide association studies in humans and the translational implications of mechanistic studies in animal disease models.

Comparing the efficacy and influence on the quality of life of three classes of drugs used in bronchial asthma - a prospective study

OBJECTIVES

To compare the efficacy of formoterol, montelukast and acebrophylline when used in combination with budesonide in patients with bronchial asthma and to determine their role in the improvement of the quality of life of patients.

MATERIALS AND METHODS

A total of 75 patients were divided into 3 groups based on treatment given - formoterol 6 mcg/puff + budesonide 100 mcg/puff combination inhaler, 2 puffs twice daily; oral montelukast 10 mg once daily + budesonide 100 mcg/puff, 2 puffs twice daily and oral acebrophylline 100 mg twice daily + budesonide 100 mcg/puff, 2 puffs twice daily. The patients were followed-up for 4 wk after initiating treatment. Spirometry values - forced expiratory volume in 1 second (FEV1) and peak expiratory flow rate (PEFR), before and after treatment were recorded. The quality of life was assessed before and after treatment using Asthma Quality of Life Questionnaire (AQLQ). Analysis was done using repeated measures ANOVA followed by Bonferroni's post-hoc test.

RESULTS

As compared to baseline values, FEV1, PEFR and Quality of Life showed significant improvement in all 3 groups after 4 wk of treatment (p-value < 0.01). Three patients in acebrophylline-treated group reported gastric irritation while no adverse effects were reported in the other groups.

CONCLUSION

Formoterol, montelukast or acebrophylline combined with inhaled corticosteroids have similar efficacy in the treatment of asthma.

Antileukotriene reverts the early effects of inflammatory response of distal parenchyma in experimental chronic allergic inflammation

Aims. Compare the effects of montelukast or dexamethasone in distal lung parenchyma and airway walls of guinea pigs (GP) with chronic allergic inflammation. Methods. GP have inhaled ovalbumin (OVA group-2x/week/4weeks). After the 4th inhalation, GP were treated with montelukast or dexamethasone. After 72 hours of the 7th inhalation, GP were anesthetised, and lungs were removed and submitted to histopathological evaluation. Results. Montelukast and dexamethasone treatments reduced the number of eosinophils in airway wall and distal lung parenchyma compared to OVA group (P < 0.05). On distal parenchyma, both treatments were effective in reducing RANTES, NF-κB, and fibronectin positive cells compared to OVA group (P < 0.001). Montelukast was more effective in reducing eotaxin positive cells on distal parenchyma compared to dexamethasone treatment (P < 0.001), while there was a more expressive reduction of IGF-I positive cells in OVA-D group (P < 0.001). On airway walls, montelukast and dexamethasone were effective in reducing IGF-I, RANTES, and fibronectin positive cells compared to OVA group (P < 0.05). Dexamethasone was more effective in reducing the number of eotaxin and NF-κB positive cells than Montelukast (P < 0.05). Conclusions. In this animal model, both treatments were effective in modulating allergic inflammation and remodeling distal lung parenchyma and airway wall, contributing to a better control of the inflammatory response.

Systems pharmacology models can be used to understand complex pharmacokinetic-pharmacodynamic behavior: an example using 5-lipoxygenase inhibitors

Zileuton, a 5-lipoxygenase (5LO) inhibitor, displays complex pharmaokinetic (PK)-pharmacodynamic (PD) behavior. Available clinical data indicate a lack of dose–bronchodilatory response during initial treatment, with a dose response developing after ~1–2 weeks. We developed a quantitative systems pharmacology (QSP) model to understand the mechanism behind this phenomenon. The model described the release, maturation, and trafficking of eosinophils into the airways, leukotriene synthesis by the 5LO enzyme, leukotriene signaling and bronchodilation, and the PK of zileuton. The model provided a plausible explanation for the two-phase bronchodilatory effect of zileuton–the short-term bronchodilation was due to leukotriene inhibition and the long-term bronchodilation was due to inflammatory cell infiltration blockade. The model also indicated that the theoretical maximum bronchodilation of both 5LO inhibition and leukotriene receptor blockade is likely similar. QSP modeling provided interesting insights into the effects of leukotriene modulation.

Pharmacotherapy challenges of Fontan-associated plastic bronchitis: a rare pediatric disease

Pediatric pharmacotherapy is often challenging due to the paucity of available clinical data on the safety and efficacy of drugs that are commonly used in children. This quandary is even more prevalent in children with rare diseases. Although extrapolations for dosing and administration are often made from available adult data with similar disease states, this translation becomes even more problematic in rare pediatric diseases. Understanding of rare disease pathophysiology is typically poor, and few, if any, effective therapies have been studied and identified. One condition that illustrates these issues is plastic bronchitis, a rare, most often pediatric disease that is characterized by the production of obstructive bronchial airway casts. This illness primarily occurs in children with congenital heart disease, often after palliative surgery. Plastic bronchitis is a highly clinically relevant and therapeutically challenging problem with a high mortality rate, and, a generally accepted effective pharmacotherapy regimen has yet to be identified. Furthermore, the disease is ill defined, which makes timely identification and treatment of children with plastic bronchitis difficult. The pharmacotherapies currently used to manage this disease are largely anecdotal and vary between the use of macrolide antibiotics, mucolytics, bronchodilators, and inhaled fibrinolytics in a myriad of combinations. The purpose of this review is 2-fold: first, to highlight the dilemma of treating plastic bronchitis, and second, to bring attention to the continuing need for studies of drug therapies used in children so safe and effective drug regimens can be established, particularly for rare diseases.

Cysteinyl leukotriene-receptor-1 antagonists interfere with PGE2 synthesis by inhibiting mPGES-1 activity

Because of their favourable safety profile and beneficial anti-inflammatory properties, the CysLT1 receptor antagonists (LTRA), montelukast, zafirlukast and pranlukast are approved for the treatment of asthma and are frequently prescribed as add-on therapeutics to reduce the amount of inhaled glucocorticoids and β2-agonists. There is evidence that some of these anti-inflammatory properties might be of a secondary nature and therefore, unrelated to the CysLT1 antagonism. Here, we show that LTRA inhibit PGE2 formation in cytokine-stimulated Hela and A549 carcinoma cells and in lipopolysaccharide (LPS)-stimulated human leukocyte preparations (IC50∼20μM). Neither expression of enzymes involved in PGE2 synthesis nor arachidonic acid release and COX activities were inhibited by the compounds. In contrast, mPGES-1 activity was suppressed at low micromolar levels (IC50 between 2 and 4μM). This suppression was specific for PGE2 synthesis, since PGD2 and PGI2 levels in LPS-stimulated leukocyte preparations were not negatively affected. PGF2α levels were concomitantly inhibited, probably due to its direct synthesis from PGE2. Several major conclusions can be drawn from this study: (A) clinical trials investigating elevated doses of the compounds are helpful to confirm suppression of PGE2 synthesis in vivo; (B) studies investigating the role of CysLTs in cell culture or animal models of inflammation and cancer have to be reassessed carefully, if higher doses of LTRA were applied or serum levels in cell culture assays were low; and (C) LTRA may serve as new scaffolds for the development of potent, selective and well tolerated mPGES-1 inhibitors.

Montelukast in asthma: a review of its efficacy and place in therapy

Many studies have been published in the last 10 years on the efficacy and safety of montelukast in asthma since this drug entered the market. Experimental studies, in vitro and in vivo, and clinical studies on large numbers of patients with asthma of different severity have clearly demonstrated that montelukast is able to modify the pathophysiological mechanisms of the disease, and to improve to some extent the clinical and functional manifestations of asthma. Studies of montelukast as monotherapy or in combination with other drugs, mainly inhaled corticosteroids (ICS), versus different comparator drugs have contributed to the positioning of montelukast in the different levels of asthma treatment, according to the Global Initiative for Asthma Guidelines. Montelukast may be used as monotherapy as an alternative to low-dose ICS (particularly in a step-down strategy) or in addition to ICS for improving clinical manifestations by an increase in anti-inflammatory effects and a sparing of corticosteroids. The heterogeneity of asthma has received a large amount of attention in the last few years in order to better tailor treatment according to the different clinical and biological phenotypes of asthma. Montelukast has proven to be particularly effective in exercise-induced asthma and in asthma associated with allergic rhinitis. Other phenotypes where montelukast is effective include asthma in obese patients, asthma in smokers, aspirin-induced asthma and viral-induced wheezing episodes. The safety profile of montelukast is very good, and the suspicions of increased risk of Churg-Strauss syndrome or suicide have not been confirmed.

Tissue-based and bronchoalveolar lavage-based biomarkers in asthma

In this article, tissue and bronchoalveolar lavage biomarkers of asthma are evaluated for their use in asthma and evaluated in the context of the phenotype that they may best represent. It is hoped that studies that better link biomarkers to specific phenotypes will eventually improve the ability to evaluate genetic features, diagnose, measure progression, and tailor treatments. Although some biomarkers may only be associated with disease, it is also likely that some may be mechanistically involved. Some of these biomarkers may then also become targets for specific treatment.

Montelukast versus inhaled corticosteroids in the management of pediatric mild persistent asthma

International guidelines recommend the use of inhaled corticosteroids (ICSs) as the preferred therapy, with leukotriene receptor antagonists (LTRAs) as an alternative, for the management of persistent asthma in children. Montelukast (MLK) is the first LTRA approved by the Food and Drug Administration for the use in young asthmatic children.Therefore, we performed an analysis of studies that compared the efficacy of MLK versus ICSs. We considered eligible for the inclusion randomized, controlled trials on pediatric populations with Jadad score > 3, with at least 4 weeks of treatment with MLK compared with ICS.Although it is important to recognize that ICSs use is currently the recommended first-line treatment for asthmatic children, MLK can have consistent benefits in controlling asthmatic symptoms and may be an alternative in children unable to use ICSs or suffering from poor growth. On the contrary, low pulmonary function and/or high allergic inflammatory markers require the corticosteroid use.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes (5-lipoxygenase inhibitors and leukotriene receptors antagonists) serve as alternative monotherapy to inhaled corticosteroids (ICS) in the management of recurrent and/or chronic asthma in adults and children.

OBJECTIVES

To determine the safety and efficacy of anti-leukotrienes compared to inhaled corticosteroids as monotherapy in adults and children with asthma and to provide better insight into the influence of patient and treatment characteristics on the magnitude of effects.

SEARCH METHODS

We searched MEDLINE (1966 to Dec 2010), EMBASE (1980 to Dec 2010), CINAHL (1982 to Dec 2010), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (Dec 2010), abstract books, and reference lists of review articles and trials. We contacted colleagues and the international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

We included randomised trials that compared anti-leukotrienes with inhaled corticosteroids as monotherapy for a minimum period of four weeks in patients with asthma aged two years and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data. The primary outcome was the number of patients with at least one exacerbation requiring systemic corticosteroids. Secondary outcomes included patients with at least one exacerbation requiring hospital admission, lung function tests, indices of chronic asthma control, adverse effects, withdrawal rates and biological inflammatory markers.

MAIN RESULTS

Sixty-five trials met the inclusion criteria for this review. Fifty-six trials (19 paediatric trials) contributed data (representing total of 10,005 adults and 3,333 children); 21 trials were of high methodological quality; 44 were published in full-text. All trials pertained to patients with mild or moderate persistent asthma. Trial durations varied from four to 52 weeks. The median dose of inhaled corticosteroids was quite homogeneous at 200 µg/day of microfine hydrofluoroalkane-propelled beclomethasone or equivalent (HFA-BDP eq). Patients treated with anti-leukotrienes were more likely to suffer an exacerbation requiring systemic corticosteroids (N = 6077 participants; risk ratio (RR) 1.51, 95% confidence interval (CI) 1.17, 1.96). For every 28 (95% CI 15 to 82) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional patient with an exacerbation requiring rescue systemic corticosteroids. The magnitude of effect was significantly greater in patients with moderate compared with those with mild airway obstruction (RR 2.03, 95% CI 1.41, 2.91 versus RR 1.25, 95% CI 0.97, 1.61), but was not significantly influenced by age group (children representing 23% of the weight versus adults), anti-leukotriene used, duration of intervention, methodological quality, and funding source. Significant group differences favouring inhaled corticosteroids were noted in most secondary outcomes including patients with at least one exacerbation requiring hospital admission (N = 2715 participants; RR 3.33; 95% CI 1.02 to 10.94), the change from baseline FEV(1) (N = 7128 participants; mean group difference (MD) 110 mL, 95% CI 140 to 80) as well as other lung function parameters, asthma symptoms, nocturnal awakenings, rescue medication use, symptom-free days, the quality of life, parents' and physicians' satisfaction. Anti-leukotriene therapy was associated with increased risk of withdrawals due to poor asthma control (N = 7669 participants; RR 2.56; 95% CI 2.01 to 3.27). For every thirty one (95% CI 22 to 47) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional withdrawal due to poor control. Risk of side effects was not significantly different between both groups.

AUTHORS' CONCLUSIONS

As monotherapy, inhaled corticosteroids display superior efficacy to anti-leukotrienes in adults and children with persistent asthma; the superiority is particularly marked in patients with moderate airway obstruction. On the basis of efficacy, the results support the current guidelines' recommendation that inhaled corticosteroids remain the preferred monotherapy. 

Asthma outcomes: biomarkers

BACKGROUND

Measurement of biomarkers has been incorporated within clinical research studies of asthma to characterize the population and associate the disease with environmental and therapeutic effects.

OBJECTIVE

National Institutes of Health institutes and federal agencies convened an expert group to propose which biomarkers should be assessed as standardized asthma outcomes in future clinical research studies.

METHODS

We conducted a comprehensive search of the literature to identify studies that developed and/or tested asthma biomarkers. We identified biomarkers relevant to the underlying disease process progression and response to treatment. We classified the biomarkers as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Ten measures were identified; only 1, multiallergen screening to define atopy, is recommended as a core asthma outcome. Complete blood counts to measure total eosinophils, fractional exhaled nitric oxide (Feno), sputum eosinophils, urinary leukotrienes, and total and allergen-specific IgE are recommended as supplemental measures. Measurement of sputum polymorphonuclear leukocytes and other analytes, cortisol measures, airway imaging, breath markers, and system-wide studies (eg, genomics, proteomics) are considered as emerging outcome measures.

CONCLUSION

The working group participants propose the use of multiallergen screening in all asthma clinical trials to characterize study populations with respect to atopic status. Blood, sputum, and urine specimens should be stored in biobanks, and standard procedures should be developed to harmonize sample collection for clinical trial biorepositories.

Cysteinyl leukotrienes regulate TGF-β(1) and collagen production by bronchial fibroblasts obtained from asthmatic subjects

BACKGROUND

Cysteinyl leukotrienes (CysLTs) play an important role in airway inflammation in asthma but their role in airway remodeling is not completely known.

METHODS

CysLTs receptors and procollagen I(α(1)) mRNA were determined by qPCR. Procollagen protein production was measured by RIA and TGF-β(1) expression was determined by ELISA. TGF-β receptor expression was assessed by western blots.

RESULTS

CysLT1R, TGF-β-R1 and active TGF-β(1) are highly expressed in cells from asthmatics compared to normal controls. LTD(4) increased significantly procollagen I(α(1)) mRNA and protein expression in fibroblasts from asthmatics. This increase was blocked by CysLTs receptor antagonist. LTD(4) increased significantly mRNA expression of TGF-β(1) and active form production in fibroblasts from asthmatics. Inhibition of TGF-β(1) signaling blocked LTD(4)-induced procollagen I(α(1)) expression.

CONCLUSIONS

Fibroblasts from asthmatic subjects express high level of CysLT1R. LTD(4) regulates procollagen I(α(1)) transcription in fibroblasts derived from asthmatic patients by modulating TGF-β(1) expression. This suggests that CysLTs may play a role in regulating collagen deposition in asthma.

A geranyl acetophenone targeting cysteinyl leukotriene synthesis prevents allergic airway inflammation in ovalbumin-sensitized mice

Asthma is associated with increased pulmonary inflammation and airway hyperresponsiveness. The current use of corticosteroids in the management of asthma has recently raised issues regarding safety and lack of responsiveness in 5-10% of asthmatic individuals. The aim of the present study was to investigate the therapeutic effect of a non-steroidal small molecule that has cysteinyl leukotriene (cysLT) inhibitory activity, upon attenuation of allergic lung inflammation in an acute murine model. Mice were sensitized with ovalbumin (OVA) and treated with several intraperitoneal doses (100, 20, 2 and 0.2mg/kg) of 2,4,6,-trihydroxy-3-geranylacetophenone (tHGA). Bronchoalveolar lavage was performed, blood and lung samples were obtained and respiratory function was measured. OVA sensitization increased pulmonary inflammation and pulmonary allergic inflammation was significantly reduced at doses of 100, 20 and 2mg/kg with no effect at the lowest dose of 0.2mg/kg. The beneficial effects in the lung were associated with reduced eosinophilic infiltration and reduced secretion of Th2 cytokines and cysLTs. Peripheral blood reduction of total IgE was also a prominent feature. Treatment with tHGA significantly attenuated altered airway hyperresponsiveness as measured by the enhanced pause (Penh) response to incremental doses of methacholine. These data demonstrate that tHGA, a synthetic non-steroidal small molecule, can prevent acute allergic inflammation. This proof of concept opens further avenues of research and development of tHGA as an additional option to the current armamentarium of anti-asthma therapeutics.

The assessment of the optimal duration of early intervention with montelukast in the treatment of Japanese cedar pollinosis symptoms induced in an artificial exposure chamber

Objective

The study objective was to investigate the prophylactic efficacy of montelukast (MLK) 10 mg in suppressing seasonal allergic rhinitis (SAR) symptoms induced by Japanese cedar (JC) pollen and to determine how many days before exposure to JC in the artificial exposure chamber (OHIO chamber) would be optimal to start administration.

Methods

This was a single-institution, double-blind, randomized placebo-controlled four-group parallel inter-group comparison study. Adult volunteers with JC pollinosis were divided into four groups: an MLK 7-day administration group (n = 27), an MLK 3-day administration group (n = 27), an MLK 1-day administration group (n = 26), and a placebo group (n = 26). The mean change in total nasal symptom scores (nasal obstruction, nasal discharge and sneezing) (TNSS) and each of the nasal symptom scores during exposure of JC pollen in the OHIO chamber were investigated.

Results

The mean change in TNSS was significantly lower in the MLK treatment group, regardless of the number of days of administration, than in the placebo group (p = 0.0192). The results for the individual nasal symptoms showed that nasal obstruction was significantly suppressed in the 1-day administration group as compared with placebo (p = 0.0076), but no differences were found in sneezing score between any of the groups. For nasal discharge, we found a trend towards the effect clearing up after 3 days of administration. No serious adverse events were observed during the study.

Conclusion

Although this study was acute and this artificial exposure model was conducted out of the pollen season, nasal symptoms that developed in the pollen exposure chamber, especially nasal obstruction, were significantly suppressed by starting oral administration of MLK 10 mg at least 1 day before exposure. These results suggest that prophylactic administration of MLK is effective and safe in the treatment of SAR.

Cysteinyl leukotriene antagonism inhibits bronchoconstriction in response to hypertonic saline inhalation in asthma

BACKGROUND

In asthma, cysteinyl leukotrienes (CysLTs) play varying roles in the bronchomotor response to multiple provocative stimuli. The contribution of CysLTs on the airway's response to hypertonic saline (HS) inhalation in asthma is unknown. Whether polymorphisms in the leukotriene biosynthetic pathway affect the contribution of CysLTs to this response is also unknown.

METHODS

In a prospective, randomized, double-blind, placebo-controlled cross-over study, mild and moderate asymptomatic asthmatics underwent inhaled 3% HS challenge by doubling the duration of nebulization (0.5, 1, 2, 4, and 8 min) 2 h after one dose of montelukast (a CysLT receptor 1 [CysLTR1] antagonist) or placebo, and after three-week courses. We examined the effect of the leukotriene C(4) synthase (LTC(4)S) polymorphism (A-444C) on the efficacy of montelukast against HS inhalation in an exploratory manner.

RESULTS

In 37 subjects, 2 h after administration of montelukast, the mean provocative dose of HS required to cause a 20% drop in FEV(1) (HS-PD(20)) increased by 59% (9.17 ml after placebo vs. 14.55 ml after montelukast, p=0.0154). Three weeks of cysLTR1 antagonism increased the HS-PD(20) by 84% (10.97 vs. 20.21 ml, p=0.0002). Three weeks of CysLTR1 antagonism appeared to produce greater effects on blocking bronchial hyper-responsiveness (2 h vs. three-week HS-PD(20) values 14.55 vs. 20.21 ml respectively, p=0.0898). We did not observe an effect of the LTC(4)S polymorphism on the response to CysLTR1 antagonism in this cohort.

CONCLUSIONS

A significant proportion of HS-induced bronchoconstriction is mediated by release of leukotrienes as evidenced by substantial acute inhibition with a CysLTR1 antagonist. There was a trend toward greater inhibition of bronchial responsiveness with three weeks of therapy as opposed to acute CysLTR1 antagonism. Clinicaltrials.gov registration number NCT00116324.