Effect of montelukast on exhaled leukotrienes and quality of life in asthmatic patients

Vascular Inflammatory Markers as Predictors of Peripheral Arterial Disease Patients' Quality-of-Life Changes after Endovascular Treatment

The association between chronic inflammation and depression, anxiety, anhedonia, and quality of life (QoL) has been recently emphasized. However, the pathophysiology of this relationship remains unsolved. This study aims to assess the dependence between vascular inflammation represented by eicosanoid concentration and quality of life in patients with peripheral arterial disease (PAD). A total of 175 patients undergoing endovascular treatment due to lower limbs ischemia were covered with eight years of observation after the endovascular procedure, including ankle-brachial index (ABI), color Doppler ultrasound examination, urinary leukotriene E4 (LTE4), thromboxane B2 (TXB2) and 5-Hydroxyeicosatetraenoic acid (5-HETE) measurement and quality-of-life assessment with VascuQol-6. The baseline concentrations of LTE4 and TXB2 reversely correlated with preoperative VascuQol-6 and were predictive of the postoperative values of VascuQol-6 at each follow-up. At every follow-up timepoint, the results of VascuQol-6 reflected the LTE4 and TXB2 concentrations. Higher concentrations of LTE4 and TXB2 were correlated with lower life quality during the next follow-up meeting. Changes in VascuQol-6 at eight years vs. preoperative values were reversely related to the preoperative concentrations of LTE4 and TXB2. This is the first study to confirm that changes in life quality in PAD patients undergoing endovascular treatment are highly dependent on eicosanoid-based vascular inflammation.

Role of Montelukast as Monotherapy in Improving Quality of Life of an Asthmatic Patient in Pakistan

Introduction: Uncontrolled and inadequately managed asthma substantially reduces Quality of Life (QOL) and can lead to premature death. The aim of this study is to understand the role of montelukast in improving quality of life in asthmatic patients by comparing it with placebo.

Methods: This prospective, single-arm, interventional study was conducted from September 2019 to February 2020 in the pulmonology outpatient department of a tertiary care hospital in Pakistan. All patients were prescribed montelukast (10 mg once daily).

Results: At day 28, participants had a higher score on the Asthma Quality of Life Questionnaire-Standard (AQLQ-S) overall and in all sub-domains compared to day 0. The improvement was significant overall and for the sub-domains of symptoms, activity limitations, and environmental stimuli.

Conclusion: Montelukast has an effective role in asthma control as well as in improving the quality of life in the Pakistani population.

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.

Montelukast Improves Symptoms and Lung Function in Asthmatic Women Compared With Men

Purpose: Gender differences exist in the prevalence of asthma and allergic diseases, partially due to the effects of sex hormones on the development of allergic manifestations. Women, compared with men, are more prone to suffer allergic asthma, experience difficulties in controlling asthma symptoms, and show adverse responses to drugs. However, there are knowledge gaps on the effectiveness of anti-leukotrienes drugs on lung function, symptoms, and pulmonary and systemic inflammation in adult asthmatic women compared with men. We conducted a prospective cohort study to characterize the effectiveness of an anti-leukotrienes drug, montelukast (MS), in asthmatic adult women and men.

Methods: Twenty-one asthmatic subjects (11 women and 10 men), who were on low-dose inhaled corticosteroids (ICS), were treated with MS. The optimal control of the symptoms was achieved in both groups according to the Global Initiative for Asthma guidelines. At enrollment, and after 13 weeks from the beginning of MS, pulmonary function tests and asthma control tests were performed, and the fraction of exhaled nitric oxide and blood eosinophils levels were measured.

Results: From baseline until the end of the study, women treated with MS + ICS had better control of the asthmatic symptoms, defined as higher asthma control test (ACT) score (17.00 ± 1.07 to 23.36 ± 0.45; p < 0.0015), improved pulmonary function [with higher forced expiratory volume in 1 s (from 77.25 ± 6.79 to 103.88 ± 6.24; p < 0.0077)], and forced vital capacity (from 91.95 ± 6.81 to 113.17 ± 4.79; p < 0.0183) compared with men. Interestingly, MS + ICS-treated women had significantly lower levels of blood eosinophils (from 5.27 ± 0.30 to 3.30 ± 0.31; p < 0.0449) and exhaled nitric oxide (from 44.70 ± 7.30 to 25.20 ± 3.90; p < 0.0294) compared with men.

Conclusion: The treatment with MS, added to ICS, in women leads to better control of symptoms, better management of lung function, and decreased inflammation levels compared with ICS + MS treatment in men.

Role of Montelukast in Improving Quality of Life in Patients with Persistent Asthma

Introduction

Maintenance therapy of asthma has a crucial role in keeping the disease dormant and preventing frequent acute exacerbations. Asthma control may be achieved by inhaled corticosteroids (ICS) and/or long-acting beta-agonists (LABA). Leukotriene receptor antagonist - montelukast - may be added as an add-on to ICS/LABA or may also be given in monotherapy. The aim of this study was to evaluate the role of montelukast monotherapy as asthma control and its impact on the quality of life of these patients.

Methods

In this prospective, open-label, interventional study, montelukast 10 mg once daily was given to patients with mild to moderate persistent asthma for four weeks. Quality of life (QOL) was assessed on the Asthma Quality of Life Questionnaire - Standard (AQLQ-S) questionnaire. Asthma control was assessed on the Asthma Control Test (ACT). Data was entered and analyzed using SPSS version 23.0.

Results

On AQLQ-S, overall QOL improved with one month of montelukast therapy significantly. On sub-scales, except for emotional function, all other three sub-scales including symptoms, activity limitation, and environmental function improved significantly. Asthma control score also significantly improved with one month of montelukast therapy.

Conclusion

Montelukast has an effective role in asthma control and improvement of QOL in patients with mild to moderate persistent asthma.

Effectiveness and Quality of Life with Montelukast in Asthma - A double-blind randomized control trial

Objective:

To determine the role of montelukast – a leukotriene receptor antagonist (LTRA) – in improving the quality of life (QOL) and asthma control of adult patients with mild to moderate persistent asthma.

Methods:

Randomized, double-blind, placebo-controlled, non-crossover trial was conducted from March 2017 till November 2018 in three hospitals of Karachi and Hyderabad. Adults of age 15 years or more with mild to moderate persistent asthma. Treatment group was administered tablet montelukast 10mg once daily; the other group was given a similar looking placebo; as an adjuvant to the current medication. QOL was assessed with Asthma Quality of Life Questionnaire – Standard (AQLQ-S) before and after the treatment. Asthma control was monitored via Asthma Control Test (ACT).

Results:

After 4 weeks, the mean ± SD of overall QOL on AQLQ-S improved from 3.74±0.88 to 5.06±0.89 for montelukast group and from 3.58±0.92 to 4.71±0.97 for placebo group (p=0.02). The improvement in sub-domains of symptoms, activity, and emotional functions was not significant; however, the sub-domain “environmental stimuli” significantly improved with 5.06±0.89 for montelukast group and 4.71±0.97 for placebo group (p=0.02). The mean ± SD of ACT, after four weeks, for montelukast group was 18.19±2.91 and for placebo group 17.28±3.36. Only on ACT, Montelukast did not show any statistically insignificant results.

Conclusion:

The role of montelukast in improving QOL of adult patients with mild to moderate persistent asthma is quite beneficial. It improves patient quality of life. It has the ease of once daily oral administration and also eradicates side effects associated with long-term adherence to steroids.

Childhood asthma biomarkers: present knowledge and future steps

Asthma represents the most common chronic respiratory disease of childhood. Its current standard diagnosis relies on patient history of symptoms and confirmed expiratory airflow limitation. Nevertheless, the spectrum of asthma in clinical presentation is broad, and both symptoms and lung function may not always reflect the underlying airway inflammation, which can be determined by different pathogenetic mechanisms. For these reasons, the identification of objective biomarkers of asthma, which may guide diagnosis, phenotyping, management and treatment is of great clinical utility and might have a role in the development of personalized therapy. The availability of non-invasive methods to study and monitor disease inflammation is of relevance especially in childhood asthma. In this sense, a promising role might be played by the measurement of exhaled biomarkers, such as exhaled nitric oxide (FE(NO)) and molecules in exhaled breath condensate (EBC). Furthermore, recent studies have shown encouraging results with the application of the novel metabolomic approach to the study of exhaled biomarkers. In this paper the existing knowledge in the field of asthma biomarkers, with a special focus on exhaled biomarkers, will be highlighted.

Elevated exhaled leukotriene B₄ in the small airway compartment in children with asthma

BACKGROUND

Inflammatory processes in the asthmatic lung involve the large and small airway and alveolar sites. Leukotriene B4 (LTB₄) is an important disease marker, but its role in inflammation of the small airways in asthma has not been established yet.

OBJECTIVE

To distinguish between large and small airway or alveolar LTB₄ concentrations in children with asthma using the new technique of fractionated exhaled breath condensate sampling.

METHODS

Sixty-eight children (9-17 years old, 33 children with asthma and 35 controls) underwent fractional exhaled nitric oxide (FeNO) measurements, lung function testing, and collection of fractionated exhaled breath condensate using a capnograph-based approach. The LTB₄ concentrations in the small airway or alveolar and large airway fractions were correlated to disease status, lung function impairment, and clinical parameters.

RESULTS

Children with asthma had significantly higher LTB₄ concentrations in the small airway or alveolar fraction than controls (5.58 pg/mL; 95% interquartile range [IQR], 2.0-11.77 pg/mL; vs 2.0 pg/mL; 95% IQR, 2.0-6.2 pg/mL; P = .003). No difference was found between the groups in the large airway fraction. Children with obstructive lung function impairment (forced expiratory volume in 1 second z score <-1.65) had increased small airway or alveolar LTB₄ concentrations compared with children without impairment (2.0 pg/mL; 95% IQR, 2.0-9.21 pg/mL; vs 18.32 pg/mL; 95% IQR, 3.7-23.02 pg/mL; P = .04). Children with asthma but without pathologic obstructive lung function still had higher LTB₄ concentrations than controls (5.57 pg/mL; 95% IQR, 2.00-10.60 pg/mL; vs 2.00 pg/mL; 95% IQR, 2.00-6.20 pg/mL; P = .01).

CONCLUSION

LTB₄ is detectable and elevated in the small airway or alveolar fraction of exhaled breath condensate in pediatric asthma. Because of the possibility of detecting elevated levels in patients without lung function impairment in controlled disease, it may be used as a noninvasive marker of small airways disease; however, future long-term studies are needed.

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.

Cys-leukotrienes promote fibrosis in a mouse model of eosinophil-mediated respiratory inflammation

Leukotrienes (i.e., products of the 5-lipoxygenase pathway) are thought to be contributors to lung pathologies. Moreover, eosinophils have been linked with pulmonary leukotriene activities both as potential sources of these mediators and as responding effector cells. The objective of the present study was to define the role(s) of leukotrienes in the lung pathologies accompanying eosinophil-associated chronic respiratory inflammation. A transgenic mouse model of chronic T helper (Th) 2-driven inflammation expressing IL-5 from T cells and human eotaxin-2 locally in the lung (I5/hE2) was used to define potential in vivo relationships among eosinophils, leukotrienes, and chronic Th2-polarized pulmonary inflammation. Airway levels of cys-leukotrienes and leukotriene B4 (LTB4) are both significantly elevated in I5/hE2 mice. The eosinophil-mediated airway hyperresponsiveness (AHR) characteristic of these mice was abolished in the absence of leukotrienes (i.e., 5-lipoxygenase-deficient I5/hE2). More importantly, the loss of leukotrienes led to an unexpectedly significant decrease in collagen deposition (i.e., pulmonary fibrosis) that accompanied elevated levels of IL-4/-13 and TGF-β in the lungs of I5/hE2 mice. Further studies using mice deficient for the LTB4 receptor (BLT-1(-/-)/I5/hE2) and I5/hE2 animals administered a cys-leukotriene receptor antagonist (montelukast) demonstrated that the AHR and the enhanced pulmonary fibrosis characteristic of the I5/hE2 model were uniquely cys-leukotriene-mediated events. These data demonstrate that, similar to allergen challenge models of wild-type mice, cys-leukotrienes underlie AHR in this transgenic model of severe pulmonary Th2 inflammation. These data also suggest that an underappreciated link exists among eosinophils, cys-leukotriene-mediated events, and fibrotic remodeling associated with elevated levels of IL-4/-13 and TGF-β.

Cough, asthma, and cysteinyl-leukotrienes

Asthma is a chronic inflammatory disease of the lower airways, involving various cells such as eosinophils, and cytokines and mediators. Cyteinyl-leukotrienes (cys-LTs) are one of the chemical mediators that play major pathophysiological roles in asthma. They are produced by eosinophils and mast cells, and induce bronchoconstriction, mucous hypersecretion, microvascular leakage, eosinophil chemotaxis and airway remodeling. Anti-leukotrienes, including leukotriene receptor antagonists (LTRAs) which block cysLT1 receptors, exert both bronchodilatory and anti-inflammatory effects and are utilized as second- to third-line controller medication of persistent asthma. Cough is a major symptom of asthma, and cough variant asthma (CVA) is an asthma phenotype that solely presents with coughing. Sputum levels of cys-LTs are increased in patients with CVA. Antitussive effects of monotherapy with LTRAs in patients with CVA have been reported. We have recently demonstrated that 4 weeks' treatment with an LTRA montelukast exerted anti-inflammatory effect as proved by a decrease of sputum eosinophils, in addition to attenuation of cough VAS and capsaicin cough sensitivity, as reported previously. Spirometry, airway responsiveness, and impulse oscillation indices (respiratory resistance and reactance) were unchanged. These results suggested that the antitussive effect of montelukast in CVA might be attributable to its anti-inflammatory ability rather than bronchodilation. The treatment did not affect sputum levels of mediators (cys-LTs, LTB4, PGD2, PGE2, PGF2α, and TXB2). Since inhaled corticosteroid does not seem to affect cough sensitivity while attenuating cough in patients with CVA, LTRAs may involve different mechanism(s) from that of corticosteroid. LTRAs must theoretically be effective against cough of asthmatic subjects through its "anti-asthma" effects, while evidence supporting direct antitussive effects of cys-LTs on "cough receptors" is scarce. An important clinical question is that whether LTRAs involve non-specific antitussive effects. While a definite answer is not available yet, this possibility seems unlikely at the moment, although some secondary anti-inflammatory properties have been reported for montelukast. This issue needs to be clarified by future research to avoid overuse of this expensive class of medication.

[Interest for evaluation of bronchial inflammation in asthma]

Asthma is a heterogeneous chronic inflammatory disease. The respiratory functional tests are sometimes insufficient to confirm the diagnosis. Other tools are developed to estimate the bronchial inflammation such as tests of bronchial provocation, measure of exhaled nitric oxide, induced sputum and exhaled breath condensate. This review presents these non-invasive methods, approaches their interests on the identification of the disease and the treatment.

Lung function and biomarkers of airway inflammation during and after hospitalization for acute exacerbations of childhood asthma associated with viral respiratory symptoms

BACKGROUND

There are limited data assessing relationships between biomarkers of inflammation and lung function after hospitalization for asthma exacerbations in children.

OBJECTIVE

To assess the associations in asthmatic children among changes in lung function, fraction of exhaled nitric oxide (FENO), and cysteinyl leukotrienes (CysLTs) in exhaled breath condensate (EBC) after hospitalization for acute asthma.

METHODS

Spirometry and FENO were measured and EBC collected for CysLT measurement from 40 children during and 1, 2, and 4 weeks after hospitalization for an asthma exacerbation and during a single-study visit for 40 healthy children.

RESULTS

Enrollment FENO and EBC CysLT concentrations were higher in the children with asthma than in healthy individuals (mean FENO, 31.6 vs 7 ppb; P < .0001; mean EBC CysLT, 7.9 vs 4.9 ppb; P = .03). Among children with asthma, improvement in lung function reached a plateau within 2 weeks after hospital discharge. The EBC CysLT concentrations were not associated with changes in lung function, use of albuterol, or use of inhaled corticosteroids (ICSs). Among asthmatic children enrollment FENO was not associated with changes in lung function during follow-up. However, among children who had an elevated enrollment FENO (≥25 ppb), patients who did not use ICSs after hospital discharge had lower end-of-study lung function than those who used ICSs. At 2 and 4 weeks after hospital discharge, FENO was higher among patients who reported albuterol use more than twice weekly and among patients who reported no ICS use.

CONCLUSION

FENO measured at hospital discharge among children hospitalized with acute asthma may be useful in identifying patients who will respond to ICS therapy.

Impact of add-on pranlukast in stable asthma; the additive effect on peripheral airway inflammation

BACKGROUND

The importance of airway inflammation has been highlighted in the pathophysiology of asthma. Even in controlled asthmatics treated with inhaled corticosteroid (ICS), residual airway inflammation is reported. Systemic therapy with oral leukotriene receptor antagonist, pranlukast, may have additive effects to improve asthma control.

METHODS

Twenty-five controlled asthmatics treated with ICS or ICS plus long-acting β2-agonist (LABA) were enrolled for a randomized crossover trial evaluating the effect of additional oral pranlukast. The patients were assigned to two groups receiving ICS (+LABA) or ICS (+LABA) + pranlukast for 8 weeks. After washout period, two groups were switched over for another 8 weeks. Fraction of exhaled nitric oxide (FeNO), lung function tests, peak expiratory flow (PEF) and asthma control test (ACT) were evaluated at the beginning and end of each period. Central airway NO flux (J'(awNO)) and peripheral airway/alveolar NO concentration (C(ANO)) were measured and adjusted for axial NO back-diffusion.

RESULTS

FEV1, % predicted, forced expired flow (FEF) (25-75), % predicted, morning PEF and ACT were significantly increased after the addition of pranlukast. Oral pranlukast administration significantly decreased both C(ANO) and corrected C(ANO).

CONCLUSIONS

The addition of oral pranlukast to ICS or ICS + LABA therapy may improve asthma control with reducing distal airway inflammation.

TRIAL REGISTRATION

UMIN 000003781.

Clinical, physiological and anti-inflammatory effect of montelukast in patients with cough variant asthma

BACKGROUND

Cough variant asthma (CVA) is a phenotype of asthma presenting solely with coughing, characterized by airway hyperresponsiveness, eosinophilic inflammation and a cough response to bronchodilators. Leukotriene receptor antagonists (LTRAs) are antiasthma medications with anti-inflammatory and bronchodilatory properties. Although LTRAs exert antitussive effects in CVA, the mechanisms involved are unknown.

OBJECTIVES

This study aimed to clarify the antitussive mechanisms of LTRAs in CVA patients.

METHODS

We prospectively observed the effect of montelukast (10 mg) daily for 4 weeks in 23 consecutive nonsmoking adults with anti-inflammatory treatment-naive CVA. We evaluated, before and after treatment, the cough visual analogue scale (VAS), pulmonary function (spirometry and impulse oscillation), methacholine airway responsiveness, cough receptor sensitivity, expressed by the concentration of capsaicin inducing 2 or more (C2) and 5 or more (C5) coughs, sputum eosinophil counts and levels of inflammatory mediators, including cysteinyl leukotrienes, leukotriene B(4), prostaglandin (PG) D(2), PGE(2), PGF(2)(α) and thromboxane B(2). We compared the baseline characteristics of the patients based on the symptomatic response to montelukast, defined as a decrease in the cough VAS of >25% (n = 15) or ≤25% (n = 8).

RESULTS

Montelukast significantly decreased the cough VAS (p = 0.0008), sputum eosinophil count (p = 0.013) and cough sensitivity (C2: p = 0.007; C5: p = 0.039), whereas pulmonary function, airway responsiveness and sputum mediator levels remained unchanged. Multivariate analysis showed that a better response to montelukast was associated solely with younger age (p = 0.032).

CONCLUSION

The antitussive effect of montelukast in CVA may be attributed to the attenuation of eosinophilic inflammation rather than its bronchodilatory properties.

[Montelukast in the treatment of mild to moderate persistent asthma]

INTRODUCTION

Anti-inflammatory preventive treatment is recommended in cases of persistent asthma. Besides inhaled corticosteroids (ICS), which represent the mainstay of treatment, other therapeutic options are available, of which only antileukotrienes are approved for all age groups.

BACKGROUND

Given as a substitute of low-dose ICS, montelukast prevents exacerbations as efficiently and for a longer period than long-acting β2-agonists. Montelukast is as efficient as doubling the dose of ICS on asthma symptoms in cases of inadequate control with low-dose ICS. Combined with ICS, it can lead to better control of asthma and potentially to ICS sparing.

CONCLUSIONS

Given the efficacy, tolerance and long-term treatment compliance of montelukast in mild persistent asthma in adults and children, montelukast, given as a substitute or combined with ICS, could contribute to enhanced control of asthma, especially in children.

Exhaled breath condensates in asthma: diagnostic and therapeutic implications

Exhaled breath condensate (EBC) collection and analysis offers a unique non-invasive method to sample the airway lining fluid. It enables classification and quantification of airway inflammation associated with various pulmonary diseases such as asthma. Over the last decade, innumerable efforts have been made to identify biomarkers in EBC for diagnosis and management of asthma. The aim of this review is to consolidate information available to date, summarize findings from studies and identify potential biomarkers which need further refinement through translational research prior to application in clinical practice.

Effects of sample processing, time and storage condition on cysteinyl leukotrienes in exhaled breath condensate

Cysteinyl leukotrienes (CysLTs) can be measured in exhaled breath condensate (EBC); however, there is considerable variation in reported EBC CysLT concentrations from asthmatic and healthy subjects between published studies, which may be partially explained by CysLT degradation during processing and storage. We assessed CysLT stability over 6 months in EBC from healthy subjects stored at -80 °C, layered with argon and then stored at -80 °C or stored in 0.2% formic acid in methanol at -80 °C following solid-phase extraction (SPE). We found significant CysLT degradation over time in both spiked and unspiked EBC samples stored at -80 °C or layered with argon. CysLT recovery was significantly greater after storage for 6 months in 0.2% formic acid in methanol following SPE; however, there was substantial variability in endogenous CysLT recovery over time, possibly attributable to inter- and intra-assay variability at the low end of the CysLT assay range. Despite the greater recovery of CysLTs in EBC stored in methanol following SPE, the degree of variability introduced by this method appears unacceptably high. We believe that the development of more sensitive and less variable methods for quantifying CysLTs in EBC are required before CysLTs can reliably be utilized as biomarkers in exhaled breath. Sample processing and storage, as well as inter- and intra-assay variability, should be carefully considered in the design of clinical studies that include assessments of EBC constituents as biomarkers.

Eoxins: a new inflammatory pathway in childhood asthma

BACKGROUND

Increased levels of leukotrienes (LTs) in exhaled breath condensate (EBC) are associated with asthma and bronchial hyperresponsiveness (BHR), whereas eicosanoids generated through the 15-lipoxygenase (LO) pathway (15-hydroxyeicosatetraenoic acid [HETE] and eoxins) have been less studied.

OBJECTIVE

We investigated whether metabolites of the 5- and 15-LO pathways in EBC are associated with childhood asthma, asthma severity, and clinical parameters.

METHODS

The present study included 131 school-aged children (27 children with problematic severe asthma, 80 children with mild-to-moderate asthma, and 24 healthy children) from the Severe Asthma Recognized in Childhood study and 19 children with other nonasthmatic chronic lung diseases. Clinical work-up included spirometry, fractional exhaled nitric oxide measurements, skin prick testing, and methacholine challenge. Eicosanoids were analyzed in EBC by using mass spectrometry and are reported as concentrations (in picograms per milliliter) and eicosanoid/palmitic acid (PA) ratios.

RESULTS

Eoxin C₄/PA, eoxin D₄/PA, eoxin E₄/PA, 15-HETE/PA, and LTC₄/PA ratios were significantly increased in asthmatic versus healthy children. Eoxin D₄/PA and LTE₄/PA ratios were also significantly higher in children with BHR. A nonsignificant trend was observed toward higher eoxin/PA ratios with increasing asthma severity. In contrast to asthma, children with chronic lung disease had the highest 15-HETE/PA, LTC₄/PA, LTE₄/PA, and LTB₄/PA ratios.

CONCLUSION

The results point to increased activity of the 15-LO inflammatory pathway in childhood asthma. Mass spectrometric analyses of EBC demonstrate that increased eoxin levels not only accompany the increased 5-LO product LTC₄ but are also associated with BHR. These markers might represent a new therapeutic target for asthma treatment.

Montelukast as an alternative to low-dose inhaled corticosteroids in the management of mild asthma (the SIMPLE trial): an open-label effectiveness trial

OBJECTIVE

To evaluate the effectiveness of montelukast as monotherapy for patients with mild asthma who remain uncontrolled or unsatisfied while on inhaled corticosteroid (ICS) monotherapy.

DESIGN

A multicentre, open-label study. Patients (six years of age or older) had ICS therapy discontinued and were treated with orally administered montelukast once daily for six weeks.

MAIN OUTCOME MEASURES

The primary outcome measure was the rate at which asthma symptom control was achieved or maintained after six weeks of treatment. The secondary outcome measures were to compare compliance and physician satisfaction, and to further assess the safety and tolerability of montelukast.

RESULTS

Of the 534 patients enrolled, 481 (90.1%) completed the study. Mean (+/- SD) age was 27.8+/-19.0 years. The number of patients with uncontrolled symptoms decreased from 455 (85.2%) at baseline to 143 (26.8%) at week 6 (P<0.001), and mean Asthma Control Questionnaire score decreased from 1.4+/-0.8 to 0.6+/-0.6 (P<0.001), representing a clinically significant improvement. Of the 79 patients with controlled asthma symptoms at baseline, 73.4% maintained asthma control at week 6. Compliance to asthma therapy increased from 41% at baseline for ICS to 88% at week 6 for montelukast (P<0.001). Physician satisfaction with treatment increased from 43% to 85% (P<0.001) and patient satisfaction increased from 45% at baseline to 94% at week 6. No serious adverse events were reported over the course of the study.

CONCLUSION

Montelukast is an effective and well-tolerated alternative to ICS treatment in patients with mild asthma who are uncontrolled or unsatisfied with low-dose ICS therapy.

Montelukast and bronchial inflammation in asthma: a randomised, double-blind placebo-controlled trial

BACKGROUND

Examination of bronchoalveolar lavage, induced sputum, and peripheral blood indicate that cysteinyl leukotriene receptor blockers decrease inflammatory cells in asthma but these do not examine airway tissue per se.

OBJECTIVES

Our objective was to determine the effect of montelukast, a leukotriene receptor antagonist, on airway tissue inflammatory cells by direct bronchoscopic examination of the bronchial mucosa.

METHODS

Adult subjects with mild asthma (pre-bronchodilator FEV(1)> or =70% predicted; PC(20) of < or =4 mg/mL) were given 10mg/day oral montelukast (N=38) or placebo (N=37) for 6 weeks. Bronchial mucosal eosinophils and mast cells were identified and counted.

RESULTS

Change from baseline in numbers of biopsy EG2+ ("activated") eosinophils was the primary endpoint; numbers of total (chromotrope 2R+) eosinophils and (tryptase+) mast cells were secondary. Unexpectedly, there were many patients with zero EG2+ eosinophils at baseline. There was a within-group decrease in EG2+ cells, from 13.54 cells/mm (at baseline) to 0.79 cells/mm at 6 weeks in the montelukast group (LS mean change; 95% confidence interval=-13.59 [-25.45, -1.74]cells/mm; P<0.05), a change not observed in the placebo group (-1.17 [-13.26, 10.91]cells/mm; NS). The zero-inflated Poisson statistical model demonstrated that montelukast significantly reduced post-treatment EG2+ cells by 80% compared with placebo (95% CI [70.6-86.8%]; P<0.0001). The data for total eosinophils showed similar changes. The reduction in mast cell numbers was 12% (95% CI [7.9, 16.0]; P<0.0001).

CONCLUSION

Direct examination of airway tissue confirms that montelukast decreases the number of eosinophils and mast cells in asthma.

Effect of fluticasone 250 microg/salmeterol 50 microg and montelukast on exhaled nitric oxide in asthmatic patients

BACKGROUND

Monitoring noninvasive biomarkers of inflammation is an important adjunct in asthma therapy.

OBJECTIVE

The goal of the present study was to identify airway and alveolar site(s) of inflammation using exhaled nitric oxide (NO) as a marker in asthmatic patients, and to evaluate the NO response to maintenance fluticasone 250 microg/salmeterol 50 microg (F/S) and add-on montelukast 10 mg (M).

METHODS

Thirty (24 women) nonsmoking, mild to moderate asthmatic patients were studied, mean age (+/- SD) 43+/-9 years, treated with F/S for more than one year. All were clinically stable for longer than eight weeks and had not taken oral corticosteroids and/or leukotriene antagonists for eight weeks before the present study. Spirometry, Juniper asthma symptom score, fractional exhaled NO (FENO) 100 mL/s, bronchial NO and alveolar NO concentration (CANO) were measured in a single-blind, nonrandomized crossover study.

PROTOCOL

Visit 1: baseline F/S; visit 2: after four weeks of F/S plus M; visit 3: after four weeks of S plus M; and visit 4: after four weeks of S only. Values in asthmatic patients were also compared with 34 nonsmoking age-matched healthy controls with normal lung function.

RESULTS

After 180 microg aerosolized metered dose inhaler albuterol, the forced expiratory volume in 1 s at baseline was 2.6+/-0.8 L (86%+/-16% of the predicted value) and the forced expiratory volume in 1 s over the forced vital capacity was 77%+/-9% (mean +/- SD), and was similar at visits 2 to 4. Juniper scores were mildly abnormal at visits 1 to 3, but significantly worse (P=0.03) at visit 4 versus visits 1 to 3. FENO values at visits 1 to 3 were similar but significantly increased (P=0.007) at visit 4. Bronchial NO was higher (P=0.03) at visit 4, versus visits 1 and 2, and was no different at visit 3. Compared with the healthy subjects, FENO and bronchial NO values were abnormal (greater than the normal mean plus 2 SD) in 33% of asthmatic patients at visits 1 to 3. CANO was similar for visits 1 to 4. CANO was abnormal (greater than the normal mean + 2 SD) in 20% of asthmatic patients.

CONCLUSION

In clinically stable asthmatic patients, despite controller treatment including moderate-dose inhaled corticosteroids and add-on M, 33% of mild to moderate asthmatic patients have ongoing nonsuppressed bronchial sites of increased NO production, compared with healthy control subjects. These controllers have no effect on CANO, which was abnormal in 20% of the asthmatic patients studied. The addition of add-on M to baseline moderate-dose inhaled corticosteroid did not further reduce total exhaled, bronchial and/or alveolar NO production.

Exhaled breath condensate in patients with asthma: implications for application in clinical practice

Exhaled breath condensate (EBC) analysis, a rather appealing and promising method, can be used to evaluate conveniently and non-invasively a wide range of molecules from the respiratory tract, and to understand better the pathways propagating airway inflammation. A large number of mediators of inflammation, including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, prostanoids, nitrogen oxides, peptides and cytokines, have been studied in EBC. Concentrations of such mediators have been shown to be related to the underlying asthma and its severity and to be modulated by therapeutic interventions. Despite the encouraging positive results to date, the introduction of EBC in everyday clinical practice requires the resolution of some methodological pitfalls, the standardization of EBC collection and finally the identification of a reliable biomarker that is reproducible has normal values and provides information regarding the underlying inflammatory process and the response to treatment. So far, none of the parameters studied in EBC fulfils the aforementioned requirements with one possible exception: pH. EBC pH is reproducible, has normal values, reflects a significant part of asthma pathophysiology and is measurable on-site with standardized methodology although some methodological aspects of measurement of pH in EBC (e.g. the effect of ambient CO(2), sample de-aeration, time for pH measurement) require further research. However, EBC pH has not been evaluated prospectively as a guide for treatment, in a manner similar to exhaled NO and sputum eosinophils. EBC represents a simple and totally non-invasive procedure that may contribute towards our understanding of asthma pathophysiology. Besides the evaluation of new biomarkers, the standardization of the already existing procedures is warranted for the introduction of EBC in clinical practice.

Biomarkers in exhaled breath condensate: a review of collection, processing and analysis

Exhaled breath condensate (EBC) is a potential rich source for countless biomarkers that can provide valuable information about respiratory as well as systemic diseases. EBC has been studied in a variety of diseases including allergic rhinitis, asthma, chronic obstructive lung disease, cystic fibrosis, lung cancer, and obstructive sleep apnea syndrome. Although numerous biomarkers have been discovered and studied in EBC, the methods of collection and biomarker detection have not been fully standardized. While leaving standardization methods up to individual labs for the present time is optimal for the continued discovery of new biomarkers in EBC, this decreases the reproducibility and generalizability of the findings. In this review we will discuss specific biomarkers studied in specific diseases as well as some of the related technical issues including collection, processing and analysis.

The link between allergic rhinitis and asthma: a role for antileukotrienes?

Allergic rhinitis and asthma are both chronic heterogeneous disorders, with an overlapping epidemiology of prevalence, health care costs and social costs in quality of life. Both are inflammatory disorders with a similar pathophysiology, and both share some treatment approaches. However, each disorder has an array of treatments used separately in controlling these atopic disorders, from inhaled corticosteroids, beta(2)-agonists and antihistamines to newer monoclonal antibody-based treatments. The present article reviews the shared components of allergic rhinitis and asthma, and examines recent evidence supporting antileukotrienes as effective agents in reducing the symptoms of both diseases.

Alternative splicing of the G protein-coupled receptor superfamily in human airway smooth muscle diversifies the complement of receptors

G protein-coupled receptors (GPCRs) are the largest signaling family in the genome, serve an expansive array of functions, and are targets for approximately 50% of current therapeutics. In many tissues, such as airway smooth muscle (ASM), complex, unexpected, or paradoxical responses to agonists/antagonists occur without known mechanisms. We hypothesized that ASM express many more GPCRs than predicted, and that these undergo substantial alternative splicing, creating a highly diversified receptor milieu. Transcript arrays were designed detecting 434 GPCRs and their predicted splice variants. In this cell type, 353 GPCRs were detected (including 111 orphans), with expression levels varying by approximately 900-fold. Receptors used for treating airway disease were expressed lower than others with similar signaling properties, indicating potentially more effective targets. A disproportionate number of Class-A peptide-group receptors, and those coupling to G(q)/(11) or G(s) (vs. G(i)), was found. Importantly, 192 GPCRs had, on average, five different expressed receptor isoforms because of splicing events, including alternative splice donors and acceptors, novel introns, intron retentions, exon(s) skips, and novel exons, with the latter two events being most prevalent. The consequences of splicing were further investigated with the leukotriene B4 receptor, known for its aberrant responsiveness in lung. We found transcript expression of three variants because of alternative donor and acceptor splice sites, representing in-frame deletions of 38 and 100 aa, with protein expression of all three isoforms. Thus, alternative splicing, subject to conditional, temporal, and cell-type regulation, is a major mechanism that diversifies the GPCR superfamily, creating local recepteromes with specialized environments.

Cysteinyl-leukotrienes and their receptors in asthma and other inflammatory diseases: critical update and emerging trends

Cysteinyl-leukotrienes (cysteinyl-LTs), that is, LTC4, LTD4, and LTE4, trigger contractile and inflammatory responses through the specific interaction with G protein-coupled receptors (GPCRs) belonging to the purine receptor cluster of the rhodopsin family, and identified as CysLT receptors (CysLTRs). Cysteinyl-LTs have a clear role in pathophysiological conditions such as asthma and allergic rhinitis (AR), and have been implicated in other inflammatory conditions including cardiovascular diseases, cancer, atopic dermatitis, and urticaria. Molecular cloning of human CysLT1R and CysLT2R subtypes has confirmed most of the previous pharmacological characterization and identified distinct expression patterns only partially overlapping. Interestingly, recent data provide evidence for the immunomodulation of CysLTR expression, the existence of additional receptor subtypes, and of an intracellular pool of CysLTRs that may have roles different from those of plasma membrane receptors. Furthermore, genetic variants have been identified for the CysLTRs that may interact to confer risk for atopy. Finally, a crosstalk between the cysteinyl-LT and the purine systems is being delineated. This review will summarize and attempt to integrate recent data derived from studies on the molecular pharmacology and pharmacogenetics of CysLTRs, and will consider the therapeutic opportunities arising from the new roles suggested for cysteinyl-LTs and their receptors.

Exhaled bronchial cysteinyl leukotrienes in allergic patients

PURPOSE OF REVIEW

To review the current knowledge of noninvasive monitoring of allergic airway inflammation by analysis of leukotrienes in the exhaled breath condensate.

RECENT FINDINGS

Treatment of respiratory allergies involves chronic treatment based on clinical symptoms and pulmonary function tests. Evaluation of local inflammation would be desirable but is currently not feasible because of the difficulty in sampling the airways. Recently, exhaled breath condensate collection and analysis has polarized much interest in the respiratory field. Although some methodological issues are still under scrutiny, airways inflammatory markers can be assayed with this technique. In particular, exhaled breath condensate leukotrienes have been thoroughly investigated in the setting of bronchial asthma and allergic rhinitis in adults and children. Exhaled leukotrienes are increased in patients with asthma and rhinitis during the pollen season, correlate with exacerbations and asthma severity, and are reduced by specific anti-inflammatory treatment and allergen avoidance.

SUMMARY

Some issues still prevent the use of exhaled breath condensate in clinical practice but in the research setting it has been proved to be useful for noninvasive monitoring of allergic inflammation in the lung. In particular, exhaled leukotrienes may represent valuable biomarkers for diagnostic and therapeutic purposes in allergic patients.

Improvements in distal lung function correlate with asthma symptoms after treatment with oral montelukast

STUDY OBJECTIVES

The distal airways are likely to contribute to asthma pathobiology and symptoms but have rarely been specifically evaluated in relation to systemic oral therapy. We hypothesized that treatment with montelukast, an oral cysteinyl-leukotriene receptor antagonist, would improve both proximal and distal lung physiology in patients with mild asthma.

DESIGN

Randomized, double-blind, crossover design.

SETTING

Academic referral center.

PATIENTS

Subjects with mild asthma limited to using short-acting inhaled beta(2)-agonists.

INTERVENTIONS

Nineteen subjects with mild asthma underwent a baseline assessment of lung function, lung mechanics, and symptoms, followed by randomization to therapy with montelukast, 10 mg taken in the evening, or placebo in a crossover, double-blind fashion. Each treatment phase lasted 4 weeks, with a 2-week washout period. A repeat evaluation was performed during the last week of each treatment phase.

MEASUREMENTS AND RESULTS

Montelukast resulted in improvement in (mean +/- SD) proximal and distal lung function parameters (change in FEV(1): montelukast, 0.16 +/- 0.06 L; placebo, -0.05 +/- 0.05 L; p = 0.008); change in specific conductance: montelukast, 7.2 +/- 2.9% predicted; placebo, -17 +/- 8% predicted; p = 0.007; change in % predicted residual volume [RV]: montelukast, 18.4 +/- 8.3% predicted; placebo, 3.0 +/- 2.9% predicted; p = 0.05). Improvement in symptoms (ie, wheeze and chest tightness) correlated with improvements in RV while receiving montelukast, but not while receiving placebo (Pearson coefficients: 0.55 and 0.66, respectively; p < 0.008 and 0.04, respectively).

CONCLUSIONS

The systemically acting oral agent montelukast improves proximal and distal lung physiology. Improvements in distal lung function correlate with improvements in asthma symptoms.

Treatment with 400 microg of inhaled budesonide vs 200 microg of inhaled budesonide and oral montelukast in children with moderate persistent asthma: randomized controlled trial

BACKGROUND

Montelukast is reported to be beneficial in asthma as add-on therapy to inhaled corticosteroids and may reduce the need for the latter.

OBJECTIVE

To evaluate whether a combination of oral montelukast and 200 microg of inhaled budesonide has comparable efficacy to 400 microg of inhaled budesonide alone in children with moderate persistent asthma.

METHODS

In this prospective, blinded, hospital-based randomized controlled trial, 71 children with moderate persistent asthma were randomized to receive either montelukast, 5-mg chewable tablet, with 200 microg of inhaled budesonide or only 400 microg of inhaled budesonide daily for 12 weeks. Baseline and serial measurements of forced expiratory volume in 1 second, peak expiratory flow rate, and Asthma Symptom Score were performed; the frequency and severity of exacerbations were also recorded.

RESULTS

Measurements of forced expiratory volume in 1 second, peak expiratory flow rate, and Asthma Symptom Score showed no significant differences between the 2 groups at baseline, during the serial follow-up visits, and at the end of the study. However, children who received montelukast had a greater frequency of exacerbations vs those who did not (33.3% vs 9.1%; P < .01).

CONCLUSION

The overall control of asthma with 5 mg of oral montelukast and 200 microg of inhaled budesonide is inferior to that with 400 microg of inhaled budesonide in children with moderate persistent asthma.

Acute asthma exacerbations: phenotypes and management

Acute asthma presentations account for 2 million emergency department visits annually in the United States. The causes for these presentations range from undertreated or unrecognized disease, to exacerbations of stable disease usually caused by recent exposure to triggers of exacerbations, to severe disease states unresponsive to conventional therapy. Indeed, many of these patients often exhibit both acute and chronic markers of severe asthma. The recognition of these phenotypes of acute asthma can enhance the management of these patients in acute and emergency settings. This article describes these potential phenotypes, reviews current therapies, and addresses the challenges of variability of therapeutic response in acute asthma.

Exhaled breath condensate cysteinyl leukotrienes and airway remodeling in childhood asthma: a pilot study

Background

It has been suggested that cysteinyl leukotrienes (cysLTs) play an important role in airway remodeling. Previous reports have indicated that cysLTs augment human airway smooth muscle cell proliferation. Recently, cysLTs have been measured in exhaled breath condensate (EBC). The aim of this study was to evaluate the relationship between cysLTs in EBC and another marker of airway remodeling, reticular basement membrane (RBM) thickening, in endobronchial biopsies in children.

Methods

29 children, aged 4–15 years, with moderate to severe persistent asthma, who underwent bronchoscopy as part of their clinical assessment, were included. Subjects underwent spirometry and EBC collection for cysLTs analysis, followed by bronchoscopy and endobronchial biopsy within 24 hours.

Results

EBC cysLTs were significantly lower in asthmatic children who were treated with montelukast than in those who were not (median (interquartile range) 36.62 (22.60–101.05) versus 249.1 (74.21–526.36) pg/ml, p = 0.004). There was a significant relationship between EBC cysLTs and RBM thickness in the subgroup of children who were not treated with montelukast (n = 13, r = 0.75, p = 0.003).

Conclusion

EBC cysLTs appear to be associated with RBM thickening in asthma.