Mechanisms of adverse effects of {beta}-agonists in asthma

The Wiser Strategy of Using Beta-Agonists in Asthma: Mechanisms and Rationales

Concerns regarding the safety of beta-2 agonists have led to revisions of the major asthma guidelines to better address these issues. Although these updates allow for a combination of previous and current strategies, they may confuse clinical practitioners. Beta-2 agonists are vital for alleviating asthma symptoms by relaxing smooth muscles; however, they also pose significant risks by inducing pro-inflammatory mediators both in vitro and in vivo. In addition to the risks of overuse and symptom masking, the use of beta-agonists alone at therapeutic doses can worsen airway inflammation and enhance virus-induced inflammation during asthma exacerbation. Inhaled corticosteroids (ICS) can effectively prevent these adverse effects. With new insights into the mechanisms of these adverse events, reserving short-acting beta-agonists for acute symptom relief during exacerbations and only for those who are already on ICS or oral steroids represents a careful approach to using beta-agonists with least adverse effects in patients with asthma. However, a major drawback of this approach is the potential non-compliance with ICS, leading to beta-agonist use without the necessary counteraction by ICS. An optimal strategy, both during and outside exacerbations, would integrate beta-agonists into an anti-inflammatory regimen that includes ICS, ideally combined with the same inhaler to ensure their concurrent use where finances allow. This would maintain the beneficial effects of beta-agonists, such as bronchodilation, while preventing the adverse effects from the induction of inflammatory mediators. This method is aligned with diverse clinical settings, maximizes the safe use of beta-agonists, and supports a comprehensive guideline-compliant management strategy.

Prediction of Asthma Exacerbations in Children

Asthma exacerbations are common in asthmatic children, even among those with good disease control. Asthma attacks result in the children and their parents missing school and work days; limit the patient's social and physical activities; and lead to emergency department visits, hospital admissions, or even fatal events. Thus, the prompt identification of asthmatic children at risk for exacerbation is crucial, as it may allow for proactive measures that could prevent these episodes. Children prone to asthma exacerbation are a heterogeneous group; various demographic factors such as younger age, ethnic group, low family income, clinical parameters (history of an exacerbation in the past 12 months, poor asthma control, poor adherence to treatment, comorbidities), Th2 inflammation, and environmental exposures (pollutants, stress, viral and bacterial pathogens) determine the risk of a future exacerbation and should be carefully considered. This paper aims to review the existing evidence regarding the predictors of asthma exacerbations in children and offer practical monitoring guidance for promptly recognizing patients at risk.

Asthma-related hospitalizations after implementing SABA-free asthma management with a maintenance and anti-inflammatory reliever regimen

Overreliance on short-acting β₂-agonists (SABA) has been a common feature of asthma management globally for at least 30 years. However, given the evidence against the long-term use of SABA, including potentially increased risk of exacerbations, emergency room visits, overall healthcare resource utilization, and mortality, the latest Global Initiative for Asthma report no longer recommends SABA only therapy. Since 2014, we implemented an ICS-containing reliever strategy at our asthma center at the G Baigorria Hospital in Argentina; we only administered budesonide/formoterol via a single inhaler device across the spectrum of asthma severity and completely eliminated the use of SABA therapy. In this article, we compare hospitalization data from our center, previously reported in the EAGLE study (when inhaled corticosteroids plus as-needed SABA was administered) for the years 1999 and 2004 with data from 2017 to 2018 (when budesonide/formoterol in a single inhaler device was administered as maintenance and/or anti-inflammatory reliever therapy [MART/AIR] without any SABA) from our center, to assess the impact of two distinct asthma management strategies on asthma-related hospitalizations. MART/AIR regimens in our SABA-free center reduced asthma hospitalizations from 9 (1999 and 2004) to 1 (2017 and 2018) (Fisher's exact test, p = 0.031; odds ratio = 0.11; 95% confidence interval [CI] = 0.013-0.98); the hospitalization rate was reduced by 92% (1.47% in 1999 and 2004 to 0.12% in 2017 and 2018). Our data provide preliminary real-world evidence that MART/AIR with budesonide/formoterol simultaneously with SABA elimination across asthma severities is an effective asthma management strategy for reducing asthma-related hospitalizations.

High Use of SABAs is Associated with Higher Exacerbation Rate in Dutch Patients with Asthma

PURPOSE

Many patients with asthma still have insufficient disease control, despite the availability of effective treatment options. A substantial proportion of patients appear to rely more on short-acting beta2-agonist (SABA) rather than on anti-inflammatory maintenance treatment. The aim of this study was to describe differences in indicators of asthma symptoms and exacerbations among patients using more or less SABA than the guideline-recommended threshold of <3 times/week.

PATIENTS AND METHODS

Data from Dutch respondents in the European REcognise Asthma and LInk to Symptoms and Experience (REALISE) survey were used in this post hoc analysis. The survey included asthma patients aged 18-50 years with at least two prescriptions for their asthma in the past two years. SABA use was categorized into two groups: <3 (low-SABA users) or ≥3 (high-SABA users) times in the last week.

RESULTS

Of the 736 asthma patients, 21% did not use SABA and 19% used SABA 1 to 2 times (all low SABA users) and 60% used SABA ≥3 times (high SABA users) in the last week. The majority of high and low SABA users also reported using an ICS-containing treatment. Significant differences were found for all indicators related to exacerbations (p<0.001): high SABA users more frequently used antibiotics and oral steroids, more frequently visited the emergency departments or needed an overnight hospital stay. Indicators of asthma symptoms were not significantly different between both groups.

CONCLUSION

The majority of a Dutch asthmatic population reported high SABA use and had frequent moderate/severe exacerbations. More effective interventions are needed to change healthcare providers' and patients' behaviours to improve care and reduce SABA (over)use.

Nuclear Receptors in Asthma: Empowering Classical Molecules Against a Contemporary Ailment

The escalation in living standards and adoption of 'Western lifestyle' has an allied effect on the increased allergy and asthma burden in both developed and developing countries. Current scientific reports bespeak an association between allergic diseases and metabolic dysfunction; hinting toward the critical requirement of organized lifestyle and dietary habits. The ubiquitous nuclear receptors (NRs) translate metabolic stimuli into gene regulatory signals, integrating diet inflences to overall developmental and physiological processes. As a consequence of such promising attributes, nuclear receptors have historically been at the cutting edge of pharmacy world. This review discusses the recent findings that feature the cardinal importance of nuclear receptors and how they can be instrumental in modulating current asthma pharmacology. Further, it highlights a possible future employment of therapy involving dietary supplements and synthetic ligands that would engage NRs and aid in eliminating both asthma and linked comorbidities. Therefore, uncovering new and evolving roles through analysis of genomic changes would represent a feasible approach in both prevention and alleviation of asthma.

Role of community pharmacists in educating asthmatic patients: A multi-centered cross-sectional study in Ethiopia

Background:

Effective asthma management requires a multidisciplinary approach that includes; the physician, the patient, and the patient’s family.

Objectives:

The current study aimed to assess the roles played by community pharmacists toward asthma control together with the barriers hindering their practice and possible strategies to overcome those barriers.

Methods:

A multi-centered cross-sectional study was conducted. Data was collected using a structured, self-administered questionnaire adapted from previously conducted studies and customized to fit with the current study setup. The collected data was cleaned, coded, and entered into Statistical Package for Social Sciences (SPSS) version 21 for analysis. Descriptive analysis of the collected data was conducted and the results were presented using frequency tables and graphs.

Results:

A total of 122 community pharmacy professionals; 63 from Gondar, 26 from Bahir Dar, 15 from Debre Markos, 14 from Woldia, and 4 from Debre birhan participated in the study. About 96 (78.7%) of the participants reported that they teach their patients the basic facts about asthma. More than two-thirds of the participants 85 (69.7%) also reported that they were able to identify and manage the triggering factors of asthma for their patients. Lack of pharmacist time was reported by 78 (63.9%) of the study participants as a major reason for the inadequacy of the counseling service provided.

Conclusion:

It appears evident that there is a need for continuing professional education and pharmacists to receive additional training to improve their ability to go beyond identifying a problem and suggesting therapeutic options.

Immune Modulation in Asthma: Current Concepts and Future Strategies

Asthma treatment concepts have profoundly changed over the last 20 years, from standard therapeutic regimens for all patients with asthma towards individually tailored interventions targeting treatable traits ("precision medicine"). A precise and highly effective immune modulation with minimal adverse effects plays a central role in this new concept. Recently, there have been major advances in the treatment of asthma with immune-modulatory compounds. One example is the approval of several highly potent biologics for the treatment of severe asthma. New immune-modulatory strategies are expected to enter clinical practice in the future; these innovations will be especially important for patients with treatment-resistant asthma.

Group 2 Innate Lymphoid Cells in Respiratory Allergic Inflammation

Millions of people worldwide are suffering from allergic inflammatory airway disorders. These conditions are regarded as a consequence of multiple imbalanced immune events resulting in an inadequate response with the exact underlying mechanisms still being a subject of ongoing research. Several cell populations have been proposed to be involved but it is becoming increasingly evident that group 2 innate lymphoid cells (ILC2s) play a key role in the initiation and orchestration of respiratory allergic inflammation. ILC2s are important mediators of inflammation but also tissue remodeling by secreting large amounts of signature cytokines within a short time period. Thereby, ILC2s instruct innate but also adaptive immune responses. Here, we will discuss the recent literature on allergic inflammation of the respiratory tract with a focus on ILC2 biology. Furthermore, we will highlight different therapeutic strategies to treat pulmonary allergic inflammation and their potential influence on ILC2 function as well as discuss the perspective of using human ILC2s for diagnostic purposes.

Asthma exacerbation prediction: recent insights

PURPOSE OF REVIEW

Asthma attacks are frequent in children with asthma and can lead to significant adverse outcomes including time off school, hospital admission and death. Identifying children at risk of an asthma attack affords the opportunity to prevent attacks and improve outcomes.

RECENT FINDINGS

Clinical features, patient behaviours and characteristics, physiological factors, environmental data and biomarkers are all associated with asthma attacks and can be used in asthma exacerbation prediction models. Recent studies have better characterized children at risk of an attack: history of a severe exacerbation in the previous 12 months, poor adherence and current poor control are important features which should alert healthcare professionals to the need for remedial action. There is increasing interest in the use of biomarkers. A number of novel biomarkers, including patterns of volatile organic compounds in exhaled breath, show promise. Biomarkers are likely to be of greatest utility if measured frequently and combined with other measures. To date, most prediction models are based on epidemiological data and population-based risk. The use of digital technology affords the opportunity to collect large amounts of real-time data, including clinical and physiological measurements and combine these with environmental data to develop personal risk scores. These developments need to be matched by changes in clinical guidelines away from a focus on current asthma control and stepwise escalation in drug therapy towards inclusion of personal risk scores and tailored management strategies including nonpharmacological approaches.

SUMMARY

There have been significant steps towards personalized prediction models of asthma attacks. The utility of such models needs to be tested in the ability not only to predict attacks but also to reduce them.

Effect of beta-agonists on LAM progression and treatment

Lymphangioleiomyomatosis (LAM), a rare disease of women, is associated with cystic lung destruction resulting from the proliferation of abnormal smooth muscle-like LAM cells with mutations in the tuberous sclerosis complex (TSC) genes TSC1 and/or TSC2 The mutant genes and encoded proteins are responsible for activation of the mechanistic target of rapamycin (mTOR), which is inhibited by sirolimus (rapamycin), a drug used to treat LAM. Patients who have LAM may also be treated with bronchodilators for asthma-like symptoms due to LAM. We observed stabilization of forced expiratory volume in 1 s over time in patients receiving sirolimus and long-acting beta-agonists with short-acting rescue inhalers compared with patients receiving only sirolimus. Because beta-agonists increase cAMP and PKA activity, we investigated effects of PKA activation on the mTOR pathway. Human skin TSC2^+/- fibroblasts or LAM lung cells incubated short-term with isoproterenol (beta-agonist) showed a sirolimus-independent increase in phosphorylation of S6, a downstream effector of the mTOR pathway, and increased cell growth. Cells incubated long-term with isoproterenol, which may lead to beta-adrenergic receptor desensitization, did not show increased S6 phosphorylation. Inhibition of PKA blocked the isoproterenol effect on S6 phosphorylation. Thus, activation of PKA by beta-agonists increased phospho-S6 independent of mTOR, an effect abrogated by beta-agonist-driven receptor desensitization. In agreement, retrospective clinical data from patients with LAM suggested that a combination of bronchodilators in conjunction with sirolimus may be preferable to sirolimus alone for stabilization of pulmonary function.

β2-Adrenoceptor Function in Asthma

β2-adrenoceptor agonists, often used in combination with corticosteroids, have been extensively used for the treatment of asthma. However, concerns have been raised regarding their adverse effects and safety including poor asthma control, life-threatening exacerbations, exacerbations that often require hospitalization, and asthma-related deaths. The question as to whether these adverse effects relate to the loss of their bronchoprotective action remains an interesting possibility. In the chapter, we will review the experimental evidence that describes the different potential factors and associated mechanisms that can blunt the therapeutic action of β2-adrenoceptor agonists in asthma. We show here evidence that various key inflammatory cytokines, growth factors, some respiratory viruses, certain allergens, unknown factors present in serum from atopic asthmatics have the capacity to impair β2-adrenoceptor function in airway smooth muscle, the main target of these drugs. More importantly, we present our latest research describing the role played by mast cells in impairing β2-adrenoceptor function. Although no definitive conclusion could be made regarding the implication of one single mechanism, receptor uncoupling, or receptor desensitization due to phosphorylation represents the main inhibitory pathways associated with a loss of β2-adrenoceptor function in airway smooth muscle. Targeting the pathways leading to β2-adrenoceptor dysfunction will likely provide novel therapies to improve the efficacy of β2-agonists in asthma.

Effects of β-blockers on house dust mite-driven murine models pre- and post-development of an asthma phenotype

BACKGROUND

Our previous studies suggested certain β-adrenoceptor blockers (β-blockers) attenuate the asthma phenotype in ovalbumin driven murine models of asthma. However, the ovalbumin model has been criticized for lack of clinical relevance.

METHODS

We tested the non-selective β-blockers, carvedilol and nadolol, in house dust mite (HDM) driven murine asthma models where drugs were administered both pre- and post-development of the asthma phenotype. We measured inflammation, mucous metaplasia, and airway hyper-responsiveness (AHR). We also measured the effects of the β-blockers on extracellular-signal regulated kinase (ERK 1/2) phosphorylation in lung homogenates.

RESULTS

We show that nadolol, but not carvedilol, attenuated inflammation and mucous metaplasia, and had a moderate effect attenuating AHR. Following HDM exposure, ERK1/2 phosphorylation was elevated, but the level of phosphorylation was unaffected by β-blockers, suggesting ERK1/2 phosphorylation becomes dissociated from the asthma phenotype.

CONCLUSION

Our findings in HDM models administering drugs both pre- and post-development of the asthma phenotype are consistent with previous results using ovalbumin models and show differential effects for nadolol and carvedilol on the asthma phenotype. Lastly, our data suggest that ERK1/2 phosphorylation may be involved in development of the asthma phenotype, but may have a limited role in maintaining the phenotype.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.

Bidirectional Counterregulation of Human Lung Mast Cell and Airway Smooth Muscle β2 Adrenoceptors

Human lung mast cells (HLMCs) play a central role in asthma pathogenesis through their relocation to the airway smooth muscle (ASM) bundles. β2 adrenoceptor (β2-AR)-agonists are used to relieve bronchoconstriction in asthma, but may reduce asthma control, particularly when used as monotherapy. We hypothesized that HLMC and human ASM cell (HASMC) responsiveness to β2-AR agonists would be attenuated when HLMCs are in contact with HASMCs. Cells were cultured in the presence of the short-acting β2-agonist albuterol, and the long-acting β2-agonists formoterol and olodaterol. Constitutive and FcεRI-dependent HLMC histamine release, HASMC contraction, and β2-AR phosphorylation at Tyr(350) were assessed. Constitutive HLMC histamine release was increased in HLMC-HASMC coculture and this was enhanced by β2-AR agonists. Inhibition of FcεRI-dependent HLMC mediator release by β2-agonists was greatly reduced in HLMC-HASMC coculture. These effects were reversed by neutralization of stem cell factor (SCF) or cell adhesion molecule 1 (CADM1). β2-AR agonists did not prevent HASMC contraction when HLMCs were present, but this was reversed by fluticasone. β2-AR phosphorylation at Tyr(350) occurred within 5 min in both HLMCs and HASMCs when the cells were cocultured, and was inhibited by neutralizing SCF or CADM1. HLMC interactions with HASMCs via CADM1 and Kit inhibit the potentially beneficial effects of β2-AR agonists on these cells via phosphorylation of the β2-AR. These results may explain the potentially adverse effects of β2-ARs agonists when used for asthma therapy. Targeting SCF and CADM1 may enhance β2-AR efficacy, particularly in corticosteroid-resistant patients.

Stopping long-acting beta2-agonists (LABA) for adults with asthma well controlled by LABA and inhaled corticosteroids

BACKGROUND

Poorly controlled asthma often leads to preventable exacerbations that require additional medications, as well as unscheduled hospital and clinic visits.Long-acting beta2-agonists (LABA) are commonly given to adults with asthma whose symptoms are not well controlled by inhaled corticosteroids (ICS). US and UK regulators have issued warnings for LABA in asthma, and now recommend they be used "for the shortest duration of time required to achieve control of asthma symptoms and discontinued, if possible, once asthma control is achieved".

OBJECTIVES

To compare cessation of long-acting beta2-agonists (LABA) versus continued use of LABA/inhaled corticosteroids (LABA/ICS) for adults whose asthma is well controlled, and to determine whether stopping LABA:1. results in loss of asthma control or deterioration in quality of life;2. increases the likelihood of asthma attacks or 'exacerbations'; or3. increases or decreases the likelihood of serious adverse events of any cause.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register (CAGR), www.ClinicalTrials.gov, www.who.int/ictrp/en/, reference lists of primary studies and existing reviews and manufacturers' trial registries (GlaxoSmithKline (GSK) and AstraZeneca). We searched all databases from their inception to April 2015, and we imposed no restriction on language of publication.

SELECTION CRITERIA

We looked for parallel randomised controlled trials (RCTs) of at least eight weeks' duration, in which adults whose asthma was well controlled by any dose of ICS+LABA combination therapy were randomly assigned to (1) step-down therapy to ICS alone versus (2) continuation of ICS and LABA.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all records identified by the search strategy. We used an Excel extraction tool to manage searches, document reasons for inclusion and exclusion and extract descriptive and numerical data from trials meeting inclusion criteria.Prespecified primary outcomes were (1) exacerbations requiring oral steroids, (2) asthma control and (3) all-cause serious adverse events.

MAIN RESULTS

Six randomised, double-blind studies between 12 and 24 weeks' long met the inclusion criteria. Five studies contributed data to the meta-analysis, assigning 2781 people with stable asthma to the comparison of interest. The definition of stable asthma and inclusion criteria varied across studies, and Global Initiative for Asthma (GINA) criteria were not used. Risk of bias across studies was generally low, and most evidence was rated as moderate quality.Stopping LABA might increase the number of people having exacerbations and requiring oral corticosteroids (odds ratio (OR) 1.74, 95% confidence interval (CI) 0.83 to 3.65; participants = 1257; studies = 4), although the confidence intervals did not exclude the possibility that stopping LABA was beneficial; over 17 weeks, 19 people per 1000 who continued their LABA had an exacerbation, compared with 32 per 1000 when LABA were stopped (13 more per 1000, 95% CI 3 fewer to 46 more).People who stopped LABA had worse scores on the Asthma Control Questionnaire (mean difference (MD) 0.24, 95% CI 0.13 to 0.35; participants = 645; studies = 3) and on measures of asthma-related quality of life (standardised mean difference (SMD) 0.36, 95% CI 0.15 to 0.57; participants = 359; studies = 2) than those who continued LABA, but the effects were not clinically relevant.Too few events occurred for investigators to tell whether stopping LABA has a greater effect on serious adverse events compared with continuing LABA+ICS (OR 0.82, 95% CI 0.28 to 2.42; participants = 1342; studies = 5), and no study reported exacerbations requiring an emergency department visit or hospitalisation as a separate outcome. Stopping LABA may result in fewer adverse events of any kind compared with continuing, although the effect was not statistically significant (OR 0.83, 95% CI 0.66 to 1.05; participants = 1339; studies = 5), and stopping LABA made people more likely to withdraw from participation in research studies (OR 1.95, 95% CI 1.47 to 2.58; participants = 1352; studies = 5).

AUTHORS' CONCLUSIONS

This review suggests that stopping LABA in adults who have stable asthma while they are taking a combination of LABA and ICS inhalers may increase the likelihood of asthma exacerbations that require treatment with oral corticosteroids, but this is not certain. Stopping LABA may slightly reduce asthma control and quality of life, but evidence was insufficient to show whether this had an effect on important outcomes such as serious adverse events and exacerbations requiring hospital admission, and longer trials are warranted. Trialists should include patient-important outcomes such as asthma control and quality of life and should use validated measurement tools. Definitions of exacerbations should be provided.

Stopping long-acting beta2-agonists (LABA) for children with asthma well controlled on LABA and inhaled corticosteroids

BACKGROUND

Asthma is the most common chronic medical condition among children and is one of the most common causes of hospitalisation and medical visits. Poorly controlled asthma often leads to preventable exacerbations that require additional medications, hospital stays, or treatment in the emergency department.Long-acting beta2-agonists (LABA) are the preferred add-on treatment for children with asthma whose symptoms are not well controlled on inhaled corticosteroids (ICS). The US Food and Drug Administration has issued a 'black box' warning for LABA in asthma, and now recommends that they be used "for the shortest duration of time required to achieve control of asthma symptoms and discontinued, if possible, once asthma control is achieved".

OBJECTIVES

To compare the effect on asthma control and adverse effects of stepping down to inhaled corticosteroids (ICS)-only therapy versus continuing ICS plus LABA in children whose asthma is well controlled on combined ICS and LABA therapy.

SEARCH METHODS

We searched the Cochrane Airways Group Specialised Register, and also searched www.ClinicalTrials.gov, www.who.int/ictrp/en/, reference lists of primary studies and existing reviews, and manufacturers' trial registries (GlaxoSmithKline and AstraZeneca). We searched all databases from their inception to the present, and imposed no restriction on language of publication. The most recent search was done in April 2015.

SELECTION CRITERIA

We looked for parallel randomised controlled trials of at least eight weeks' duration, available as published full text, abstract only, or unpublished data. We excluded studies including participants with other chronic respiratory comorbidities (for example bronchiectasis).We looked for studies in which children (18 years or younger) whose asthma was well controlled on any dose of ICS and LABA combination therapy were randomised to: a) step-down therapy to ICS alone or b) continued use of ICS and LABA.We included any dose of LABA (formoterol, salmeterol, vilanterol) and any dose of ICS (beclomethasone, budesonide, ciclesonide, mometasone, flunisolide, fluticasone propionate, fluticasone furoate, triamcinolone) delivered in a combination inhaler or in separate inhalers.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened all records identified in the searches. We used a data extraction tool in Microsoft Excel to manage searches and document reasons for inclusion and exclusion, and to extract descriptive and numerical data from trials meeting the inclusion criteria.The prespecified primary outcomes were exacerbations requiring oral steroids, asthma control, and all-cause serious adverse events.

MAIN RESULTS

Despite conducting extensive searches of electronic databases, trial registries and manufacturers' websites we identified no trials matching the inclusion criteria.After removing duplicates, we screened 1031 abstracts, and assessed 43 full-text articles for inclusion. We identified several adult studies, which will be summarised in a separate review (Ahmad 2014). The most common reasons for exclusion after viewing full texts were 'wrong comparison' (n = 22) and 'adult population' (n = 18).Some adult studies recruited adolescents from age 15, but none reported data separately for those under 18.

AUTHORS' CONCLUSIONS

There is currently no evidence from randomised trials to inform the discontinuation of LABAs in children once asthma control is achieved with ICS plus LABA. It is disappointing that such an important issue has not been studied, and a randomised double-blind trial recruiting children who are controlled on ICS plus LABA is warranted. The study should be large enough to assess children of different ages, and to measure the important safety and efficacy outcomes suggested in this review over at least six months.The only randomised evidence for stopping LABA has been conducted in adults; it will be summarised in a separate review.

Stage-dependent association of BDNF and TGF-β1 with lung function in stable COPD

Background

Chronic Obstructive Pulmonary Disease (COPD) is characterised by complex inflammatory, neuronal and fibrotic changes. Brain-derived Neurotrophic Factor (BDNF) is a key regulator of neuronal plasticity, whereas Transforming Growth Factor-β₁ (TGF-β₁) plays a crucial role in tissue repair and emphysema pathogenesis. Both mediators are stored in platelets and released from platelets in inflammatory conditions and during serum preparation. In patients with asthma, it was previously shown that elevated serum BDNF concentrations correlate with disease severity, whereas TGF-β₁ concentrations were normal.

Methods

In the present study, 63 patients with stable COPD (spirometric GOLD stages 2–4) and 17 age- and comorbidity-matched controls were studied. Lung function, smoking history, medication, platelet concentrations in peripheral blood and serum concentrations of BDNF, TGF-β₁ and Serotonin (5-HT) were assessed in all participants.

Results

Serum levels of both BDNF and TGF-β₁ (but not concentrations of platelets in peripheral blood) were significantly elevated in all stages of COPD as compared to controls. Highest BDNF concentrations were found in spirometric GOLD stage 3, whereas highest TGF-β₁ serum levels were found in spirometric GOLD stage 4. There were specific, stage-dependent correlations of these mediators with lung function parameters of the patients.

Conclusions

Taken together, we show that, in contrast to asthma, COPD is characterised by elevated concentrations of both BDNF and TGF-β₁ in serum. The stage-dependent association with lung function supports the hypothesis that these platelet mediators may play a role in the pathogenesis of COPD.

Use of Cardioselective ß-Blockers in Patients with Chronic Obstructive Pulmonary Disease: A Meta-Analysis of Randomized, Placebo-controlled, Blinded Trials

Objective:

To assess the effect of cardioselective b-blockers on pulmonary function in patients with chronic obstructive pulmonary disease (COPD).

Methods:

The Embase and MEDLINE™ databases and the Cochrane Controlled Trials Register were searched comprehensively to identify all relevant clinical trials in humans published between January 1966 and May 2011. Randomized, blinded, placebo-controlled trials that studied the effects of cardioselective ß-blockers on the forced expiratory volume in 1 s (FEV1) and the responsiveness of the FEV1 to ß-agonist administration in patients with COPD were included in the analysis.

Results:

Five studies were identified: four of these assessed both cardioselective and nonselective ß-blockers; one assessed only cardioselective ß-blockers. The FEV1 was shown to decrease by 0.14 l with nonselective ß-blockers and by 0.03 l with cardioselective ß-blockers. The responsive -ness of the FEV1 to ß-agonist administration decreased significantly by 13.42% after nonselective ß-blockers, but did not change significantly after cardioselective -blocker administration.

Conclusion:

This meta-analysis suggests that the use of β-blockers, especially cardioselective β-blockers, should not be contraindicated in patients with COPD.

Challenges of treating asthma in people who smoke

Cigarette smoking is common in asthma and is associated with poor symptom control and a reduced therapeutic response to inhaled and oral corticosteroids as compared with nonsmokers with asthma. This review examines the range of adverse health effects of smoking in asthma, the inflammatory mechanisms that may influence the efficacy of current drugs and discusses potential future therapeutic directions.