Ratio of leukotriene e(4) to exhaled nitric oxide and the therapeutic response in children with exercise-induced bronchoconstriction

Exercise-induced bronchoconstriction in children: Delphi study and consensus document about definition and epidemiology, diagnostic work-up, treatment, and follow-up

BACKGROUND

Exercise-induced bronchoconstriction (EIB) is common in children with asthma but can be present also in children without asthma, especially athletes. Differential diagnosis includes several conditions such as exercise-induced laryngeal obstruction (EILO), cardiac disease, or physical deconditioning. Detailed medical history, clinical examination and specific tests are mandatory to exclude alternative diagnoses. Given the high prevalence of EIB in children and its potential impact on health, sport performance, and daily levels of physical activity, health care professionals should be aware of this condition and able to provide a specific work-up for its identification. The aims of the present study were: (a) to assess the agreement among hospital pediatricians and primary care pediatricians of Emilia-Romagna Region (Italy) about the management of EIB in children and (b) formulate statements in a consensus document to help clinicians in daily clinical practice.

METHODS

According to Delphi method, a panel of specialists scored 40 statements that were then revised and discussed during online meetings to reach full consensus. Statements were then formulated.

RESULTS

To obtain full consensus, the questionnaire was administered in two rounds after full discussion of the uncertain topics on the basis of the latest evidence on EIB published over the last 10 years. Despite an overall agreement on EIB management, some gaps emerged in the sections dedicated to diagnosis and treatment. Nine summary statements on definition, pathogenesis, diagnostic work-up, treatment, and follow-up were eventually formulated.

CONCLUSIONS

This study describes the knowledge of EIB in a group of pediatricians and highlights gaps and uncertainties in diagnosis and treatment. The creation of statements shared by the specialists of the same area may improve the management of EIB in children. However, more research and evidence are needed to better clarify the best treatment and to standardize the best diagnostic protocol limiting useless examinations but at the same time assuring the best management.

Exercise-Induced Bronchoconstriction in Children: State of the Art from Diagnosis to Treatment

Exercise-induced bronchoconstriction (EIB) is a common clinical entity in people with asthma. EIB is characterized by postexercise airway obstruction that results in symptoms such as coughing, dyspnea, wheezing, chest tightness, and increased fatigue. The underlying mechanism of EIB is not completely understood. "Osmotic theory" and "thermal or vascular theory" have been proposed. Initial assessment must include a specific work-up to exclude alternative diagnoses like exercise-induced laryngeal obstruction (EILO), cardiac disease, or physical deconditioning. Detailed medical history and clinical examination must be followed by basal spirometry and exercise challenge test. The standardized treadmill running (TR) test, a controlled and standardized method to assess bronchial response to exercise, is the most adopted exercise challenge test for children aged at least 8 years. In the TR test, the goal is to reach the target heart rate in a short period and maintain it for at least 6 min. The test is then followed by spirometry at specific time points (5, 10, 15, and 30 min after exercise). In addition, bronchoprovocation tests like dry air hyperpnea (exercise and eucapnic voluntary hyperpnea) or osmotic aerosols (inhaled mannitol) can be considered when the diagnosis is uncertain. Treatment options include both pharmacological and behavioral approaches. Considering medications, the use of short-acting beta-agonists (SABA) just before exercise is the commonest option strategy, but daily inhaled corticosteroids (ICS) can also be considered, especially when EIB is not controlled with SABA only or when the patients practice physical activity very often. Among the behavioral approaches, warm-up before exercise, breathing through the nose or face mask, and avoiding polluted environments are all recommended strategies to reduce EIB risk. This review summarizes the latest evidence published over the last 10 years on the pathogenesis, diagnosis using spirometry and indirect bronchoprovocation tests, and treatment strategies, including SABA and ICS, of EIB. A specific focus has been placed on EIB management in young athletes, since this condition can not only prevent them from practicing regular physical activity but also competitive sports.

Eicosanoid Mediators in the Airway Inflammation of Asthmatic Patients: What is New?

Lipid mediators contribute to inflammation providing both pro-inflammatory signals and terminating the inflammatory process by activation of macrophages. Among the most significant biologically lipid mediators, these are produced by free-radical or enzymatic oxygenation of arachidonic acid named "eicosanoids". There were some novel eicosanoids identified within the last decade, and many of them are measurable in clinical samples by affordable chromatography-mass spectrometry equipment or sensitive immunoassays. In this review, we present some recent advances in understanding of the signaling by eicosanoid mediators during asthmatic airway inflammation. Eicosanoid profiling in the exhaled breath condensate, induced sputum, or their metabolites measurements in urine is complementary to the cellular phenotyping of asthmatic inflammation. Special attention is paid to aspirin-exacerbated respiratory disease, a phenotype of asthma manifested by the most profound changes in the profile of eicosanoids produced. A hallmark of this type of asthma with hypersensitivity to non-steroid anti-inflammatory drugs (NSAIDs) is to increase biosynthesis of cysteinyl leukotrienes on the systemic level. It depends on transcellular biosynthesis of leukotriene C₄ by platelets that adhere to granulocytes releasing leukotriene A₄. However, other abnormalities are also reported in this type of asthma as a resistance to anti-inflammatory activity of prostaglandin E₂ or a robust eosinophil interferon-γ response resulting in cysteinyl leukotrienes production. A novel mechanism is also discussed in which an isoprostane structurally related to prostaglandin E₂ is released into exhaled breath condensate during a provoked asthmatic attack. However, it is concluded that any single eicosanoid or even their complex profile can hardly provide a thorough explanation for the mechanism of asthmatic inflammation.

Leukotriene D4 nasal provocation test: Rationale, methodology and diagnostic value

Cysteinyl leukotrienes (LT) play a vital role in the pathogenesis of allergic rhinitis (AR), but few studies have investigated the nasal mucosal physiological response to LTs in AR patients. The aim of the present study was to establish the methodology and investigate the diagnostic value and safety of a leukotriene D4 (LTD4) nasal provocation test. LTD4 nasal provocation tests were performed in 26 AR patients and 16 normal control subjects. Nasal airway responsiveness was assessed by calculating the concentration of LTD4 required to cause a 60% increase in nasal airway resistance (PC60NAR-LTD4), which was measured using rhinomanometry and a composite symptom score. Receiver operating characteristic (ROC) curve was applied to evaluate the diagnostic value of LTD4 nasal provocation test, and adverse events were recorded. The study protocol was registered with the U.S. National Institutes of Health (https://clinicaltrials.gov/ct2/show/NCT01963741). PC60NAR-LTD4 in AR was significantly lower compared with that of normal controls [8.36 (IQR, 10.00) vs. 17.00 (IQR, 0.00) µg/ml, P=0.005]. Composite symptom score was higher in AR as compared with normal controls (1.19±0.94 vs. 0.12±0.50, P<0.001). The symptom scores included sneezing (0.12±0.34 vs. 0.00±0.00, P=0.149), rhinorrhea (0.79±0.66 vs. 0.06±0.25, P<0.001) and chemosis or itching of the eyes (0.06±0.25 vs. 0.21±0.42, P=0.216). High diagnostic value was indicated by the ROC [AUC: 0.822, 95%CI (0.665, 0.961)]. No serious adverse events were observed. Thus, the present results indicate that AR patients exhibited nasal hyperactivity to LTD4, and the established procedure of LTD4 nasal provocation testing is effective and safe for use in the diagnosis of AR.

Intensity of swimming exercise influences tracheal reactivity in rats

Studies that evaluate the mechanisms for increased airway responsiveness are very sparse, although there are reports of exercise-induced bronchospasm. Therefore, we have evaluated the tracheal reactivity and the rate of lipid peroxidation after different intensities of swimming exercise in rats. Thus, male Wistar rats (age 8 weeks; 250–300 g) underwent a forced swimming exercise for 1 h whilst carrying attached loads of 3, 4, 5, 6 and 8% of their body weight (groups G3, G4, G5, G6 and G8, respectively; n=5 each). Immediately after the test, the trachea of each rat was removed and suspended in an organ bath to evaluate contractile and relaxant responses. The rate of lipid peroxidation was estimated by measuring malondialdehyde levels. According to a one-way ANOVA, all trained groups showed a significant decrease in the relaxation induced by aminophylline (10⁻¹²–10⁻¹ M) (pD2=3.1, 3.2, 3.3, 3.3 and 3.2, respectively for G3, G4, G5, G6 and G8) compared to the control group (pD2=4.6) and the E_max values of G5, G6, G8 groups were reduced by 94.2, 88.0 and 77.0%, respectively. Additionally, all trained groups showed a significant increase in contraction induced by carbachol (10⁻⁹–10⁻³ M) (pD2=6.0, 6.5, 6.5, 7.2 and 7.3, respectively for G3, G4, G5, G6 and G8) compared to the control group (pD2=5.7). Lipid peroxidation levels of G3, G4 and G5 were similar in both the trachea and lung, however G6 and G8 presented an increased peroxidation in the trachea. In conclusion, a single bout of swimming exercise acutely altered tracheal responsiveness in an intensity-related manner and the elevation in lipid peroxidation indicates a degree of oxidative stress involvement.

Characteristics of respiratory syncytial virus-induced bronchiolitis co-infection with Mycoplasma pneumoniae and add-on therapy with montelukast

BACKGROUND

The influence of Mycoplasma pneumoniae (MP) infection on bronchiolitis remains unclear. Additionally, reports on the efficacies of leukotriene receptor antagonists in the treatment of bronchiolitis have been inconclusive.

METHODS

Children with respiratory syncytial virus (RSV)-induced bronchiolitis were divided into two groups: RSV+MP group and RSV group. Each group was randomly divided into two subgroups: one received routine and placebo treatment, while the other received routine and montelukast treatment for 9 months. The cumulative numbers of wheezing episodes and recurrent respiratory tract infections were recorded. Blood parameters were determined.

RESULTS

Patients in the RSV+MP group exhibited an older average age, fever, more frequent flaky and patchy shadows in chest X-rays, more frequent extrapulmonary manifestations, and longer hospital stays compared with patients in the RSV group. Additionally, higher baseline blood eosinophil counts, eosinophil cationic protein (ECP), total immunoglobulin E (IgE), interleukin (IL)-4, IL-5, IL-4/interferon-γ ratios, leukotriene (LT) B4, and LTC4, and lower baseline lipoxin A4 (LXA4)/LTB4 ratios were observed in the RSV+MP group compared with the RSV group. Montelukast treatment decreased the cumulative numbers of recurrent wheezing episodes and recurrent respiratory tract infections at 9 and 12 months. This efficacy may be related to the montelukast-induced reductions in peripheral eosinophil counts, ECP and total IgE, as well as the montelukast-dependent recovery in T helper (Th) 1/Th2 balance and LXA4/LTB4 ratios in children with bronchiolitis.

CONCLUSIONS

RSV bronchiolitis with MP infection was associated with clinical and laboratory features that differed from those of RSV bronchiolitis without MP infection. Add-on therapy with montelukast for 9 months was beneficial for children with bronchiolitis at 9 and 12 months after the initiation of treatment.

Clinical effectiveness and safety of montelukast in asthma. What are the conclusions from clinical trials and meta-analyses?

Asthma is a common childhood atopic disease associated with chronicity and impaired quality of life. As there is no cure for this disease, treatment relies on avoidance of triggers such as food and aeroallergens, the use of inhaled bronchodilators/corticosteroids and antiallergic or immunomodulating therapies. Inhaled corticosteroids (ICSs) and bronchodilators have been the mainstay. However, in Asia, myths and fallacies regarding Western medicine and corticosteroids are prevalent and lead to nonadherence to treatment. Also, use of traditional and proprietary herbal medicines is popular. In the past decades, a novel class of nonsteroidal immunomodulating montelukasts has become available. This article reviews the evidence for the effectiveness and clinical efficacy of these medications. A number of randomized and controlled trials have been performed over the years. The majority of studies confirm the usefulness of montelukast as monotherapy and add-on therapy to ICS in mild to moderate childhood asthma across all age groups. ICSs are generally superior to montelukasts for asthma management. However, montelukast has a place in the treatment of young children with viral-triggered wheezing diseases, exercise-induced asthma, and in children whose parents are steroid-phobic and find ICS unacceptable.

Pediatric exercise-induced bronchoconstriction: contemporary developments in epidemiology, pathogenesis, presentation, diagnosis, and therapy

Exercise-induced bronchoconstriction is transient narrowing of the airways following strenuous exercise. It is the earliest sign of asthma and the last to resolve. EIB is found in 90 % of asthmatics and reflects underlying control of asthma. This review is focused on the contemporary developments in pediatric EIB: the epidemiology, pathogenesis, presentation, diagnosis and management. Proper diagnosis by objective pulmonary function and/or exercise challenge and therapy should allow the pediatric asthmatic to enjoy a healthy lifestyle including participation in the chosen sport.

Addition to inhaled corticosteroids of long-acting beta2-agonists versus anti-leukotrienes for chronic asthma

BACKGROUND

Asthma patients who continue to experience symptoms despite taking regular inhaled corticosteroids (ICS) represent a management challenge. Long-acting beta2-agonists (LABA) and anti-leukotrienes (LTRA) are two treatment options that could be considered as add-on therapy to ICS.

OBJECTIVES

To compare the safety and efficacy of adding LABA versus LTRA to the treatment regimen for children and adults with asthma who remain symptomatic in spite of regular treatment with ICS. We specifically wished to examine the relative impact of the two agents on asthma exacerbations, lung function, symptoms, quality of life, adverse health events and withdrawals.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register until December 2012. We consulted reference lists of all included studies and contacted pharmaceutical manufacturers to ask about other published or unpublished studies.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) conducted in adults or children with recurrent asthma that was treated with ICS along with a fixed dose of a LABA or an LTRA for a minimum of four weeks.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias of included studies and extracted data. We sought unpublished data and further details of study design when necessary.

MAIN RESULTS

We included 18 RCTs (7208 participants), of which 16 recruited adults and adolescents (6872) and two recruited children six to 17 years of age (336) with asthma and significant reversibility to bronchodilator at baseline. Fourteen (79%) trials were of high methodological quality.The risk of exacerbations requiring systemic corticosteroids (primary outcome of the review) was significantly lower with the combination of LABA + ICS compared with LTRA + ICS-from 13% to 11% (eight studies, 5923 adults and 334 children; risk ratio (RR) 0.87, 95% confidence interval (CI) 0.76 to 0.99; high-quality evidence). The number needed to treat for an additional beneficial outcome (NNTB) with LABA compared with LTRA to prevent one additional exacerbation over four to 102 weeks was 62 (95% CI 34 to 794). The choice of LTRA, the dose of ICS and the participants' age group did not significantly influence the magnitude of effect. Although results were inconclusive, the effect appeared stronger in trials that used a single device rather than two devices to administer ICS and LABA and in trials of less than 12 weeks' duration.The addition of LABA to ICS was associated with a statistically greater improvement from baseline in lung function, as well as in symptoms, rescue medication use and quality of life, although the latter effects were modest. LTRA was superior in the prevention of exercise-induced bronchospasm. More participants were satisfied with the combination of LABA + ICS than LTRA + ICS (three studies, 1625 adults; RR 1.12, 95% CI 1.04 to 1.20; moderate-quality evidence). The overall risk of withdrawal was significantly lower with LABA + ICS than with LTRA + ICS (13 studies, 6652 adults and 308 children; RR 0.84, 95% CI 0.74 to 0.96; moderate-quality evidence). Although the risk of overall adverse events was equivalent between the two groups, the risk of serious adverse events (SAE) approached statistical significance in disfavour of LABA compared with LTRA (nine studies, 5658 adults and 630 children; RR 1.33, 95% CI 0.99 to 1.79; P value 0.06; moderate-quality evidence), with no apparent impact of participants' age group.The following adverse events were reported, but no significant differences were demonstrated between groups: headache (11 studies, N = 6538); cardiovascular events (five studies, N = 5163), osteopenia and osteoporosis (two studies, N = 2963), adverse events (10 studies, N = 5977 adults and 300 children). A significant difference in the risk of oral moniliasis was noted, but this represents a low occurrence rate.

AUTHORS' CONCLUSIONS

In adults with asthma that is inadequately controlled by predominantly low-dose ICS with significant bronchodilator reversibility, the addition of LABA to ICS is modestly superior to the addition of LTRA in reducing oral corticosteroid-treated exacerbations, with an absolute reduction of two percentage points. Differences favouring LABA over LTRA as adjunct therapy were observed in lung function and, to a lesser extend, in rescue medication use, symptoms and quality of life. The lower overall withdrawal rate and the higher proportion of participants satisfied with their therapy indirectly favour the combination of LABA + ICS over LTRA + ICS. Evidence showed a slightly increased risk of SAE with LABA compared with LTRA, with an absolute increase of one percentage point. Our findings modestly support the use of a single inhaler for the delivery of both LABA and low- or medium-dose ICS. Because of the paucity of paediatric trials, we are unable to draw firm conclusions about the best adjunct therapy in children.

Leukotriene receptor antagonists pranlukast and montelukast for treating asthma

INTRODUCTION

The prevalence of bronchial asthma, which is a chronic inflammatory disorder of the airway, is increasing worldwide. Although inhaled corticosteroids (ICS) play a central role in the treatment of asthma, they cannot achieve good control for all asthmatics, and medications such as leukotriene receptor antagonists (LTRAs) with bronchodilatory and anti-inflammatory effects often serve as alternatives or add-on drugs.

AREAS COVERED

Clinical trials as well as basic studies of montelukast and pranlukast in animal models are ongoing. This review report clarifies the current status of these two LTRAs in the treatment of asthma and their future direction.

EXPERT OPINION

LTRAs could replace ICS as first-line medications for asthmatics who are refractory to ICS or cannot use inhalant devices. Further, LTRAs are recommended for asthmatics under specific circumstances that are closely associated with cysteinyl leukotrienes (cysLTs). Considering the low incidence of both severe adverse effects and the induction of tachyphylaxis, oral LTRAs should be more carefully considered for treating asthma in the clinical environment. Several issues such as predicted responses, effects of peripheral airway and airway remodeling and alternative administration routes remain to be clarified before LTRAs could serve a more effective role in the treatment of asthma.

Role of leukotrienes in exercise-induced bronchoconstriction before and after a pilot rehabilitation training program

BACKGROUND

Whatever the initial stimulus for the exercise-induced bronchoconstriction (EIB) observed in asthmatic patients after exercise, the final effect is release of bronchoactive mediators, especially cysteinyl leukotrienes. Exercise rehabilitation training programs have been reported to protect against EIB. The exact mechanism(s) involved are not well understood. However, this protective effect may be related to adaptation and better coordination during exercise, depletion of cysteinyl leukotrienes, and/or a sluggish cysteinyl leukotriene response to exercise. The aim of the present work was to test the hypothesis that improvement in the incidence and severity of post-exercise bronchoconstriction after a rehabilitation training program is related to a change in leukotriene levels in response to exercise.

METHODS

Twenty asthmatic children aged 6-12 years and known to develop EIB were enrolled in an exercise training program for 12 weeks. The severity and incidence of EIB before and after training was assessed. Baseline and post-exercise sputum cysteinyl leukotriene levels were assessed before and after the training program.

RESULTS

The training program offered significant protection against EIB with a concomitant decrease in sputum cysteinyl leukotriene levels in response to exercise.

CONCLUSION

A training program can result in depletion and/or a sluggish cysteinyl leukotriene response to exercise and may be responsible for the protective effect of training programs on EIB. It is recommended to use an exercise rehabilitation training program as a complementary tool in the management of bronchial asthma, especially EIB.