Molecular mechanisms of combination therapy with inhaled corticosteroids and long-acting beta-agonists

Multi-omic approach associates blood methylome with bronchodilator drug response in pediatric asthma

BACKGROUND

Albuterol is the drug most widely used as asthma treatment among African Americans despite having a lower bronchodilator drug response (BDR) than other populations. Although BDR is affected by gene and environmental factors, the influence of DNA methylation is unknown.

OBJECTIVE

This study aimed to identify epigenetic markers in whole blood associated with BDR, study their functional consequences by multi-omic integration, and assess their clinical applicability in admixed populations with a high asthma burden.

METHODS

We studied 414 children and young adults (8-21 years old) with asthma in a discovery and replication design. We performed an epigenome-wide association study on 221 African Americans and replicated the results on 193 Latinos. Functional consequences were assessed by integrating epigenomics with genomics, transcriptomics, and environmental exposure data. Machine learning was used to develop a panel of epigenetic markers to classify treatment response.

RESULTS

We identified 5 differentially methylated regions and 2 CpGs genome-wide significantly associated with BDR in African Americans located in FGL2 (cg08241295, P = 6.8 × 10-9) and DNASE2 (cg15341340, P = 7.8 × 10-8), which were regulated by genetic variation and/or associated with gene expression of nearby genes (false discovery rate < 0.05). The CpG cg15341340 was replicated in Latinos (P = 3.5 × 10-3). Moreover, a panel of 70 CpGs showed good classification for those with response and nonresponse to albuterol therapy in African American and Latino children (area under the receiver operating characteristic curve for training, 0.99; for validation, 0.70-0.71). The DNA methylation model showed similar discrimination as clinical predictors (P > .05).

CONCLUSIONS

We report novel associations of epigenetic markers with BDR in pediatric asthma and demonstrate for the first time the applicability of pharmacoepigenetics in precision medicine of respiratory diseases.

The effectiveness of dexamethasone as a combination therapy for COVID-19

Coronavirus disease 2019 (COVID-19) was reported as a global pandemic in March 2020 after invading many countries and leaving behind tens of thousands of infected patients in a brief time span. Approval of a few vaccines has been obtained and their efficacy of varying degrees established. Still, there is no effective pharmaceutical agent for the treatment of COVID-19 though several drugs are undergoing clinical trials. Recent studies have shown that dexamethasone, a corticosteroid, can reduce the rate of COVID-19-related mortality in the intensive care unit by 35 % for patients who are on mechanical ventilation. Although variable efficacy of other combination therapies has been reported for treating COVID-19 associated with acute respiratory distress syndrome (ARDS), dexamethasone is an extensively used drug in many treatment regimens against COVID-19. The current review aims to explore the role of dexamethasone as an efficient combination treatment for COVID-19.

Inhaled Therapies for Asthma and Chronic Obstructive Pulmonary Disease

Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases which are characterized by chronic inflammation and an increase in mucus production, and are highly prevalent conditions. Despite recent advances and multiple available therapies, there remains a significant unmet medical need. Over the past 40 years, the introduction of new classes of safe and effective therapy is insufficient. In spite of the high burden of asthma and COPD among patients, there are fewer new approved therapies in comparison to cardiovascular, metabolic and neurological diseases due to few drug candidates and a higher failure rate in the development of respiratory medicine. Lung diseases are amongst the leading causes of death globally with asthma being one of the most prevalent respiratory diseases, which affects people of all ages but, despite effective therapies available, many patients are poorly controlled and have a low quality of life. COPD is currently ranked as the fourth cause of death worldwide and predicted to become the third leading cause of death in 2030. The development of more effective treatments is urgently needed in order to reduce the high mortality rate and the enormous suffering from asthma and COPD. Various inhalation devices with different classes of medications are the foundation as therapies in both asthma and COPD. This article gives a comprehensive review of the promising inhaled therapies in the treatment of asthma and COPD. However, the lack of disease control in asthma and COPD patients may be due to numerous reasons. The association between non-adherence to guidelines on the part of the health care provider and poor inhalation technique and/or non-adherence to the prescribed treatment plan by the patients is common. It is therefore essential to discuss the different delivery systems and the methods used in asthma and COPD patients.

Chemocentric Informatics Analysis: Dexamethasone Versus Combination Therapy for COVID-19

COVID-19 is a biphasic infectious disease with no approved vaccine or pharmacotherapy. The first drug that has shown promise in reducing COVID-19 mortality in severely-ill patients is dexamethasone, a cheap, well-known anti-inflammatory glucocorticoid, approved for the treatment of inflammatory conditions including respiratory diseases such as asthma and tuberculosis. However, about 80% of COVID-19 patients requiring oxygenation, and about 67% of patients on ventilators, are not responsive to dexamethasone therapy mainly. Additionally, using higher doses of dexamethasone for prolonged periods of time can lead to severe side effects and some patients may develop corticosteroid resistance leading to treatment failure. In order to increase the therapeutic efficacy of dexamethasone in COVID-19 patients, while minimizing dexamethasone-related complications that could result from using higher doses of the drug, we applied a chemocentric informatics approach to identify combination therapies. Our results indicated that combining dexamethasone with fast long-acting beta-2 adrenergic agonists (LABAs), such as formoterol and salmeterol, can ease respiratory symptoms hastily, until dexamethasone's anti-inflammatory and immunosuppressant effects kick in. Our studies demonstrated that LABAs and dexamethasone (or other glucocorticoids) exert synergistic effects that will augment both anti-inflammatory and fibronectin-mediated anticoagulant effects. We also propose other alternatives to LABAs that are supported by sound systems biology evidence, such as nitric oxide. Other drugs such as sevoflurane and treprostinil interact with the SARS-CoV-2 interactome and deserve further exploration. Moreover, our chemocentric informatics approach provides systems biology evidence that combination therapies for COVID-19 will have higher chances of perturbing the SARS-CoV-2 human interactome, which may negatively impact COVID-19 disease pathways.

Relaxant Action of Diclofenac Sodium on Mouse Airway Smooth Muscle

Diclofenac sodium (DCF) is a nonsteroidal anti-inflammatory drug (NSAID) and is widely used as an analgesic and anti-inflammatory agent. Herein, we found that DCF could relax high K+ (80 mM K+)-/ACh-precontracted tracheal rings (TRs) in mice. This study aimed to elucidate the underlying mechanisms of DCF-induced relaxations. The effects of DCF on airway smooth muscle (ASM) cells were explored using multiple biophysiological techniques, such as isometric tension measurement and patch-clamping experiments. Both high K+- and ACh-evoked contraction of TRs in mice were relaxed by DCF in a dose-dependent manner. The results of isometric tension and patch-clamping experiments demonstrated that DCF-induced relaxation in ASM cells was mediated by cytosolic free Ca2+, which was decreased via inhibition of voltage-dependent L-type Ca2+ channels (VDLCCs), nonselective cation channels (NSCCs), and Na+/Ca2+ exchange. Meanwhile, DCF also enhanced large conductance Ca2+ activated K+ (BK) channels, which led to the relaxation of ASMs. Our data demonstrated that DCF relaxed ASMs by decreasing the intracellular Ca2+ concentration via inhibition of Ca2+ influx and Na+/Ca2+ exchange. Meanwhile, the enhanced BK channels also played a role in DCF-induced relaxation in ASMs. These results suggest that DCF is a potential candidate for antibronchospasmic drugs used in treating respiratory diseases such as asthma and chronic obstructive pulmonary disease.

In vitro anti-inflammatory effects of AZD8999, a novel bifunctional muscarinic acetylcholine receptor antagonist /β2-adrenoceptor agonist (MABA) compound in neutrophils from COPD patients

Recent evidence indicates that AZD8999 (LAS190792), a novel muscarinic acetylcholine receptor antagonist and β2-adrenoceptor agonist (MABA) in development for chronic respiratory diseases, induces potent and sustained relaxant effects in human bronchi by adressing both muscarinic acetylcholine receptors and β2-adrenoceptor. However, the anti-inflammatory effects of the AZD8999 monotherapy or in combination with corticosteroids are unknown. This study investigates the anti-inflammatory effects of AZD8999 in monotherapy and combined with fluticasone propionate in neutrophils from healthy and chronic obstructive pulmonary disease (COPD) patients. Peripheral blood neutrophils from healthy and COPD patients were incubated with AZD8999 and fluticasone propionate, individually or in combination, for 1h followed by lipopolysaccharide (LPS) stimulation for 6h. The IL-8, MMP9, IL-1β, and GM-CSF release was measured in cell culture supernatants. AZD8999 shows ~ 50% maximum inhibitory effect and similar potency inhibiting the released cytokines in neutrophils from healthy and COPD patients. However, while fluticasone propionate suppresses mediator release in neutrophils from healthy patients, COPD neutrophils are less sensitive. The combination of non-effective concentrations of AZD8999 (0.01nM) with non-effective concentrations of fluticasone propionate (0.1nM) shows synergistic anti-inflammatory effects. The studied mechanisms that may be involved in the synergistic anti-inflammatory effects of this combination include the increase of glucocorticoid receptor (GR)α and MKP1 expression, the induction of glucocorticoid response element (GRE) activation and the decrease of ERK1/2, P38 and GR-Ser226 phosphorylations compared with monotherapies. In summary, AZD8999 shows anti-inflammatory effects in neutrophils from COPD patients and induces synergistic anti-inflammatory effects when combined with fluticasone propionate, supporting the use of MABA/ICS combination therapy in COPD.

Glucocorticosteroids

Glucocorticosteroids are the most effective anti-inflammatory therapy for asthma but are relatively ineffective in COPD. Glucocorticoids are broad-spectrum anti-inflammatory drugs that suppress inflammation via several molecular mechanisms. Glucocorticoids suppress the multiple inflammatory genes that are activated in asthma by reversing histone acetylation of activated inflammatory genes through binding of ligand-bound glucocorticoid receptors (GR) to coactivator molecules and recruitment of histone deacetylase-2 (HDAC2) to the activated inflammatory gene transcription complex (trans-repression). At higher concentrations of glucocorticoids GR homodimers interact with DNA recognition sites to activate transcription through increased histone acetylation of anti-inflammatory genes and transcription of several genes linked to glucocorticoid side effects (trans-activation). Glucocorticoids also have post-transcriptional effects and decrease stability of some proinflammatory mRNAs. Decreased glucocorticoid responsiveness is found in patients with severe asthma and asthmatics who smoke, as well as in all patients with COPD. Several molecular mechanisms of glucocorticoid resistance have now been identified which involve phosphorylation and other post-translational modifications of GR. HDAC2 is markedly reduced in activity and expression as a result of oxidative/nitrative stress and pi3 kinase-δ inhibition, so that inflammation is resistant to the anti-inflammatory actions of glucocorticoids. Dissociated glucocorticoids and selective GR modulators which show improved trans-repression over trans-activation effects have been developed to reduce side effects, but so far it has been difficult to dissociate anti-inflammatory effects from adverse effects. In patients with glucocorticoid resistance alternative anti-inflammatory treatments are being investigated as well as drugs that may reverse the molecular mechanisms of glucocorticoid resistance.

Fluticasone/salmeterol reduces remodelling and neutrophilic inflammation in severe equine asthma

Asthmatic airways are inflamed and undergo remodelling. Inhaled corticosteroids and long-acting β2-agonist combinations are more effective than inhaled corticosteroid monotherapy in controlling disease exacerbations, but their effect on airway remodelling and inflammation remains ill-defined. This study evaluates the contribution of inhaled fluticasone and salmeterol, alone or combined, to the reversal of bronchial remodelling and inflammation. Severely asthmatic horses (6 horses/group) were treated with fluticasone, salmeterol, fluticasone/salmeterol, or with antigen avoidance for 12 weeks. Lung function, central and peripheral airway remodelling, and bronchoalveolar inflammation were assessed. Fluticasone/salmeterol and fluticasone monotherapy decreased peripheral airway smooth muscle remodelling after 12 weeks (p = 0.007 and p = 0.02, respectively). On average, a 30% decrease was observed with both treatments. In central airways, fluticasone/salmeterol reversed extracellular matrix remodelling after 12 weeks, both within the lamina propria (decreased thickness, p = 0.005) and within the smooth muscle layer (p = 0.004). Only fluticasone/salmeterol decreased bronchoalveolar neutrophilia (p = 0.03) to the same extent as antigen avoidance already after 8 weeks. In conclusion, this study shows that fluticasone/salmeterol combination decreases extracellular matrix remodelling in central airways and intraluminal neutrophilia. Fluticasone/salmeterol and fluticasone monotherapy equally reverse peripheral airway smooth muscle remodelling.

Appropriate use of inhaled corticosteroids in COPD: the candidates for safe withdrawal

International guidance on chronic obstructive pulmonary disease (COPD) management recommends the use of inhaled corticosteroids (ICS) in those patients at increased likelihood of exacerbation. In spite of this guidance, ICS are prescribed in a large number of patients who are unlikely to benefit. Given the evidence of the risks associated with ICS and the limited indications for their use, there is interest in understanding the effects of withdrawing ICS when prescribed inappropriately. In this review, we discuss the findings of large ICS withdrawal trials, with primary focus on the more recent trials using active comparators. Data from these trials indicate that ICS may be withdrawn without adverse impact on exacerbation risk and patient-reported outcomes in patients with moderate COPD and no history of frequent exacerbations. Considering the safety concerns associated with ICS use, these medications should be withdrawn in patients for whom they are not recommended, while maintaining adequate bronchodilator therapy.

Effect of budesonide and azelastine on histamine signaling regulation in human nasal epithelial cells

Both glucocorticoids and H1-antihistamines are widely used on patients with airway diseases. However, their direct effects on airway epithelial cells are not fully explored. Therefore, we use the primary culture of human nasal epithelial cells (HNEpC) to delineate in vitro mucosal responses to above two drugs. HNEpC cells were cultured with/without budesonide and azelastine. The growth rate at each group was recorded and measured as population double time (PDT). The histamine1-receptor (H1R), muscarinic1-receptor (M1R) and M3R were measured using immunocytochemistry and western blotting after 7-days treatment. Then, we used histamine and methacholine to stimulate the mucus secretion from HNEpC and observed the MUC5AC expression in culture supernatants. Concentration-dependent treatment-induced inhibition of HNEpC growth rate was observed. Cells incubated with azelastine proliferated significantly slower than that with budesonide and the combined use of those drugs led to significant PDT prolong. The immunocytochemistry showed the H1R, M1R and M3R were obviously located in the cell membrane without apparent difference after treatment. However, western blotting showed that budesonide can significantly up-regulate the H1R, M1R and M3R level while azelastine had opposite effects. Histamine and methacholine stimulated MUC5AC secretion was greater in cells treated with budesonide but was lesser in those treated with azelastine, as compared to controls. Our data suggest that both budesonide and azelastine can significantly inhibit HNEpC proliferation, and therefore, be helpful in against airway remodeling. Long-term use of budesonide might amplify histamine signaling and result in airway hyperreactivity to stimulants by enhancing H1R, M1R and M3R expression while azelastine can oppose this effect. Therefore, combined use of those two drugs in patients with chronic inflammatory airway diseases may be an ideal option.

Different approaches in the treatment of obstructive pulmonary diseases

Advances in drug formulation, inhalation device design and disease management are generating new opportunities for patients suffering from obstructive pulmonary diseases. This article provides a comprehensive review of the different promising pulmonary drug delivery technologies in the treatment of obstructive pulmonary diseases, particularly with regard to the treatment of asthma and chronic pulmonary diseases (COPD), which are increasing day by day due to increasing environmental pollution and its harmful and toxic contaminants. In the recent years, a better knowledge has been gained regarding the mechanism of action of glucocorticoids and how they suppress the chronic inflammation. New etiology has been brought into light regarding the inactivity of glucocorticoids in some patients having asthma and COPDs even though the inflammatory genes are triggered by similar molecules in both the diseases. This new knowledge has given a new platform to improve glucocorticoids and their resistance also how other combination therapy can be used for these diseases. It has also led to the quest for improving and developing other alternatives such as anti-leukotriene agents, muscarinic inhibitors, combination therapy, as well as biologic immune-modulators in the treatment of the different pulmonary diseases. Several new combinations of glucocorticoids are available in the global market for the use in pulmonary diseases especially asthma although their availability fluctuates between continents. There has been several studies done regarding the variation of effectiveness of the different inhaled glucocorticoids and hence it is important to take into consideration the different delivery systems and the methods which are used to treat the patients.

A study of use of fixed dose combinations in Ahmedabad, India

Objective:

The aim of this study was to evaluate the pattern of fixed dose combinations (FDCs) in Ahmedabad, a city in western part of India.

Materials and Methods:

Over a period of 24 months, prescriptions were collected from 24 pharmacy stores across 6 zones of Ahmedabad city. The information was recorded in pre-formed Data Record Form after written consent from the patients (or relative (s) of the patients). The pattern of use of FDC, rationality and seasonal variation in their use were analyzed. At the end of study, results were analyzed using Chi-square test.

Results:

Out of the total 1170 prescriptions, 941 (80.3%) contained 1647 FDC formulations. The average number of FDCs prescribed was 1.41 ± 1.04 (mean ± SD). The FDCs were more frequently prescribed in the age group of 31 to 40 years (23.7%) and in males (54.4%). FDCs were most commonly prescribed by oral route (92.7%). As per drug category analysis, a higher number of FDCs containing nutritional supplements (20.2%), and those for CNS (18.1%) complaints were prescribed. A seasonal analysis showed that FDCs were commonly prescribed for respiratory complaints (23.4%), central nervous system (CNS) complaints (20.3%) and as nutritional supplements (22.4%) in winter, monsoon and summer months, respectively. Only 5.8%, 9.8% and 10.9% FDCs prescribed were included in WHO (2010), National (2011) and Gujarat State (2011) Essential Medicines Lists (EML), respectively (P < 0.0001). Irrational FDCs that are banned or FDCs containing irrational active ingredients were 1343 (81.5%) and 203 (12.3%), respectively.

Conclusion:

FDCs are widely prescribed with seasonal influence in their use. FDCs containing banned or controversial ingredients are prescribed widely.

Comparison of the efficacy of ciclesonide with that of budesonide in mild to moderate asthma patients after step-down therapy: a randomised parallel-group study

BACKGROUND

Inhaled corticosteroids (ICSs) are widely used in asthma control. Ciclesonide (CIC) is an ICS with on-site lung activation for potent anti-inflammatory activity.

AIMS

This study aimed to compare the clinical benefit of CIC with budesonide (BUD) in step-down therapy.

METHODS

A total of 150 patients with mild-to-moderate asthma well controlled by a combination of ICS and long-acting β2-agonist were randomised to receive either CIC 320 μg (n=75) once daily or 2 inhalations of BUD 200 μg (n=75) twice daily for 12 weeks. The forced expiratory volume in 1s (FEV1), maximum mid-expiratory flow (MMEF) and asthma control test (ACT) scores were measured. Ranked stratification of patients and physicians was assessed.

RESULTS

Drug adherence was significantly higher in the CIC group than in the BUD group (76.0% vs. 58.7%, P=0.03). The FEV1 and MMEF remained stable throughout the 12-week CIC treatment. In the BUD group, FEV1 significantly decreased at weeks 4 and 12. MMEF had a higher value in the CIC group than in the BUD group. Both patients and physicians ranked CIC over BUD.

CONCLUSIONS

CIC is more effective and has better drug adherence than BUD as step-down treatment when asthma is well controlled by combination therapy.

Lentivirus vector-mediated Rho guanine nucleotide dissociation inhibitor 2 induces beta-2 adrenergic receptor desensitization in β2AR desensitization mice model

BACKGROUND

It is well-known that chronic administration of β2AR agonists can induce β2AR desensitization. Our previous study showed that Rho guanine nucleotide dissociation inhibitor 2 (RhoGDI2) overexpression induced beta-2 adrenergic receptor (β2AR) desensitization in airway smooth muscle cells. The purpose of this study was to further study the function of RhoGDI2 in β2AR desensitization by β2AR desensitization mouse model.

METHODS

Studies were performed using a β2AR desensitization mice model induced by salbutamol. The mice were randomly divided into five groups (n=45): RhoGDI2 overexpression group (n=10); RhoGDI2 siRNA group (n=10); empty viral vector group (n=10); experimental control group (n=10); blank control group-without any drug treatment (n=5). The first four groups were used the same methods and the same dose to establish β2AR desensitization mice model by salbutamol. The first three groups that salbutamol-treated were used for intratracheal delivery of lentiviral vectors. Airway hyperreactivity was measured through a whole-body plethysmograph system. RhoGDI2, β2AR, GRK2 mRNA and protein expression levels were then detected by RT-PCR and western blot analyses in fresh lung tissues. As well as the activity of GRK was assessed by light-dependent phosphorylation of rhodopsin.

RESULTS

We successfully constructed β2AR desensitization mouse model. As expected, airway responsiveness after inhaling acetylcholine chloride (Ach) was markedly increased in the RhoGDI2 overexpression group compared to experimental control group and blank control group when concentrations of Ach was 45 mg/mL (all P<0.05), while, it was markedly decreased in the RhoGDI2 siRNA group compared to experimental control group (P<0.05). RhoGDI2, GRK2 expressions and GRK enzymatic activity were significantly increased in RhoGDI2 overexpression group compared to experimental control group and blank control group (all P<0.05). RhoGDI2, GRK2 expressions and GRK enzymatic activity were significantly decreased in RhoGDI2 siRNA group compared to experimental control group and blank control group (all P<0.05). Conversely, β2AR expression were significantly lower in RhoGDI2 overexpression group compared to experimental control group and blank control group (all P<0.05), exhibiting an inverse correlation with RhoGDI2 expression.

CONCLUSIONS

To sum up, our present studies found that RhoGDI2 might induce β2AR desensitization and GRK2 might take part in RhoGDI2-mediated β2AR desensitization.

The beta-2-adrenoreceptor agonists, formoterol and indacaterol, but not salbutamol, effectively suppress the reactivity of human neutrophils in vitro

The clinical relevance of the anti-inflammatory properties of beta-2 agonists remains contentious possibly due to differences in their molecular structures and agonist activities. The current study has compared the effects of 3 different categories of β2-agonists, namely, salbutamol (short-acting), formoterol (long-acting) and indacaterol (ultra-long-acting), at concentrations of 1–1000 nM, with human blood neutrophils in vitro. Neutrophils were activated with either N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP, 1 µM) or platelet-activating factor (PAF, 200 nM) in the absence and presence of the β2-agonists followed by measurement of the generation of reactive oxygen species and leukotriene B4, release of elastase, and expression of the β2-integrin, CR3, using a combination of chemiluminescence, ELISA, colorimetric, and flow cytometric procedures respectively. These were correlated with alterations in the concentrations of intracellular cyclic-AMP and cytosolic Ca²⁺. At the concentrations tested, formoterol and indacaterol caused equivalent, significant (P < 0.05 at 1–10 nM) dose-related inhibition of all of the pro-inflammatory activities tested, while salbutamol was much less effective (P < 0.05 at 100 nM and higher). Suppression of neutrophil reactivity was accompanied by elevations in intracellular cAMP and accelerated clearance of Ca²⁺ from the cytosol of activated neutrophils. These findings demonstrate that β2-agonists vary with respect to their suppressive effects on activated neutrophils.

A steroid-mimicking nanomaterial that mediates inhibition of human lung mast cell responses

Water-soluble fullerenes can be engineered to regulate activation of mast cells (MC) and control MC-driven diseases in vivo. To further understand their anti-inflammatory mechanisms a C70-based fullerene conjugated to four myo-inositol molecules (C70-I) was examined in vitro for its effects on the signaling pathways leading to mediator release from human lung MC. The C70-I fullerene stabilizes MC and acts synergistically with long-acting β2-adrenergic receptor agonists (LABA) to enhance inhibition of MC mediator release through FcεRI-simulation. The inhibition was paralleled by the upregulation of dual-specificity phosphatase one (DUSP1) gene and protein levels. Concomitantly, increases in MAPK were blunted in C70-I treated cells. The increase in DUSP1 expression was due to the ability of C70-I to prevent the ubiquitination and degradation of DUSP1. These findings identify a mechanism of how fullerenes inhibit inflammatory mediator release from MC and suggest they could potentially be an alternative therapy for steroid resistant asthmatics.

FROM THE CLINICAL EDITOR

This study investigates the role and mechanism of action of fullerenes in deactivating mast cell-based inflammation, paving the way to the development of a novel, non-steroid therapy in reactive airway disease.

Airway smooth muscle in airway reactivity and remodeling: what have we learned?

It is now established that airway smooth muscle (ASM) has roles in determining airway structure and function, well beyond that as the major contractile element. Indeed, changes in ASM function are central to the manifestation of allergic, inflammatory, and fibrotic airway diseases in both children and adults, as well as to airway responses to local and environmental exposures. Emerging evidence points to novel signaling mechanisms within ASM cells of different species that serve to control diverse features, including 1) [Ca(2+)]i contractility and relaxation, 2) cell proliferation and apoptosis, 3) production and modulation of extracellular components, and 4) release of pro- vs. anti-inflammatory mediators and factors that regulate immunity as well as the function of other airway cell types, such as epithelium, fibroblasts, and nerves. These diverse effects of ASM "activity" result in modulation of bronchoconstriction vs. bronchodilation relevant to airway hyperresponsiveness, airway thickening, and fibrosis that influence compliance. This perspective highlights recent discoveries that reveal the central role of ASM in this regard and helps set the stage for future research toward understanding the pathways regulating ASM and, in turn, the influence of ASM on airway structure and function. Such exploration is key to development of novel therapeutic strategies that influence the pathophysiology of diseases such as asthma, chronic obstructive pulmonary disease, and pulmonary fibrosis.

Can the anti-inflammatory activities of β2-agonists be harnessed in the clinical setting?

Beta2-adrenoreceptor agonists (β2-agonists) are primarily bronchodilators, targeting airway smooth muscle and providing critical symptomatic relief in conditions such as bronchial asthma and chronic obstructive pulmonary disease. These agents also possess broad-spectrum, secondary, anti-inflammatory properties. These are mediated largely, though not exclusively, via interactions with adenylyl cyclase-coupled β2-adrenoreceptors on a range of immune and inflammatory cells involved in the immunopathogenesis of acute and chronic inflammatory disorders of the airways. The clinical relevance of the anti-inflammatory actions of β2-agonists, although often effective in the experimental setting, remains contentious. The primary objectives of the current review are: firstly, to assess the mechanisms, both molecular and cell-associated, that may limit the anti-inflammatory efficacy of β2-agonists; secondly, to evaluate pharmacological strategies, several of which are recent and innovative, that may overcome these limitations. These are preceded by a consideration of the various types of β2-agonists, their clinical applications, and spectrum of anti-inflammatory activities, particularly those involving adenosine 3',5'-cyclic adenosine monophosphate-activated protein kinase-mediated clearance of cytosolic calcium, and altered gene expression in immune and inflammatory cells.

Construction of a cell model of β2-adrenoceptor downregulation

OBJECTIVE

To establish a cell model of β2-adrenergic receptor (β2AR) downregulation of murine airway smooth muscle induced by salbutamol to elucidate the molecular and biological mechanisms of β2AR downregulation.

METHODS

Airway smooth muscle cells (ASMCs) derived from Balb/c mice were primary cultured. Passage 2-5 cells were characterized by cell morphology and indirect immunofluorescence. More than 95% pure cells at passage 3 or 4 were randomly divided into two groups: control and salbutamol-treated groups. β2AR mRNA and protein expression levels were then detected by RT-PCR and western blot analyses.

RESULTS

Primary cultured cells demonstrated a typical "peak and valley"-like growth characteristic. Smooth muscle α-actin filaments paralleled the cell longitudinal axis in the cytoplasm. The origin of the ASMCs was validated and consistent with their morphology and biological characteristics. β2AR mRNA expression in the salbutamol-treated group was lower than that in the control group (P<0.05), and β2AR protein expression was also markedly lower than that in the control group (P<0.05).

CONCLUSIONS

We successfully established a cell model of β2AR downregulation in ASMCs, which may provide the foundation for further study of the mechanism of β2AR downregulation in asthmatic patients.

Glucocorticoids for acute viral bronchiolitis in infants and young children

BACKGROUND

Previous systematic reviews have not shown clear benefit of glucocorticoids for acute viral bronchiolitis, but their use remains considerable. Recent large trials add substantially to current evidence and suggest novel glucocorticoid-including treatment approaches.

OBJECTIVES

To review the efficacy and safety of systemic and inhaled glucocorticoids in children with acute viral bronchiolitis.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 12), MEDLINE (1950 to January week 2, 2013), EMBASE (1980 to January 2013), LILACS (1982 to January 2013), Scopus® (1823 to January 2013) and IRAN MedEx (1998 to November 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short-term systemic or inhaled glucocorticoids versus placebo or another intervention in children under 24 months with acute bronchiolitis (first episode with wheezing). Our primary outcomes were: admissions by days 1 and 7 for outpatient studies; and length of stay (LOS) for inpatient studies. Secondary outcomes included clinical severity parameters, healthcare use, pulmonary function, symptoms, quality of life and harms.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data on study and participant characteristics, interventions and outcomes. We assessed risk of bias and graded strength of evidence. We meta-analysed inpatient and outpatient results separately using random-effects models. We pre-specified subgroup analyses, including the combined use of bronchodilators used in a protocol.

MAIN RESULTS

We included 17 trials (2596 participants); three had low overall risk of bias. Baseline severity, glucocorticoid schemes, comparators and outcomes were heterogeneous. Glucocorticoids did not significantly reduce outpatient admissions by days 1 and 7 when compared to placebo (pooled risk ratios (RRs) 0.92; 95% confidence interval (CI) 0.78 to 1.08 and 0.86; 95% CI 0.7 to 1.06, respectively). There was no benefit in LOS for inpatients (mean difference -0.18 days; 95% CI -0.39 to 0.04). Unadjusted results from a large factorial low risk of bias RCT found combined high-dose systemic dexamethasone and inhaled epinephrine reduced admissions by day 7 (baseline risk of admission 26%; RR 0.65; 95% CI 0.44 to 0.95; number needed to treat 11; 95% CI 7 to 76), with no differences in short-term adverse effects. No other comparisons showed relevant differences in primary outcomes.

AUTHORS' CONCLUSIONS

Current evidence does not support a clinically relevant effect of systemic or inhaled glucocorticoids on admissions or length of hospitalisation. Combined dexamethasone and epinephrine may reduce outpatient admissions, but results are exploratory and safety data limited. Future research should further assess the efficacy, harms and applicability of combined therapy.

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

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

Distinct PKA and Epac compartmentalization in airway function and plasticity

Asthma and chronic obstructive pulmonary disease (COPD) are obstructive lung diseases characterized by airway obstruction, airway inflammation and airway remodelling. Next to inflammatory cells and airway epithelial cells, airway mesenchymal cells, including airway smooth muscle cells and (myo)fibroblasts, substantially contribute to disease features by the release of inflammatory mediators, smooth muscle contraction, extracellular matrix deposition and structural changes in the airways. Current pharmacological treatment of both diseases intends to target the dynamic features of the endogenous intracellular suppressor cyclic AMP (cAMP). This review will summarize our current knowledge on cAMP and will emphasize on key discoveries and paradigm shifts reflecting the complex spatio-temporal nature of compartmentalized cAMP signalling networks in health and disease. As airway fibroblasts and airway smooth muscle cells are recognized as central players in the development and progression of asthma and COPD, we will focus on the role of cAMP signalling in their function in relation to airway function and plasticity. We will recapture on the recent identification of cAMP-sensing multi-protein complexes maintained by cAMP effectors, including A-kinase anchoring proteins (AKAPs), proteins kinase A (PKA), exchange protein directly activated by cAMP (Epac), cAMP-elevating seven-transmembrane (7TM) receptors and phosphodiesterases (PDEs) and we will report on findings indicating that the pertubation of compartmentalized cAMP signalling correlates with the pathopysiology of obstructive lung diseases. Future challenges include studies on cAMP dynamics and compartmentalization in the lung and the development of novel drugs targeting these systems for therapeutic interventions in chronic obstructive inflammatory diseases.

Mechanisms and management of exercise-induced asthma in elite athletes

OBJECTIVE AND METHODS

Asthma is often reported by elite athletes, especially endurance athletes. The aim of this article is to review current knowledge of mechanisms and management of exercise-induced asthma (EIA) in adult elite athletes.

RESULTS

The mechanisms underlying EIA is incompletely understood, but the two prevailing hypotheses are the hyper-osmolarity and the thermal hypothesis. Both hypotheses consider inflammation and activation of mast cells as being crucial for the development of EIA, although the assumed mechanisms triggering the inflammatory response differ. Objective testing is of utmost importance in the diagnosis of EIA in elite athletes. Management of EIA can be divided into pharmacologic and non-pharmacologic treatment. The basic principles for the treatment of EIA in elite athletes should be as for any asthmatic individual, including use of inhaled corticosteroids (ICS), β(2)-agonists, and leukotriene antagonists. However, evidence suggests that daily use of β(2)-agonists might lead to the development of tolerance. ICS therapy is, due to its anti-inflammatory effects, the recommended primary therapy for EIA also in elite athletes. All doctors treating individuals with asthma, especially elite athletes, should remain updated on doping aspects of asthma therapy. Non-pharmacologic management of EIA in elite athletes includes physical warm-up, which takes advantage of the refractory period following an attack of EIA, whereas high intake of antioxidants may reduce airway inflammation. Wearing heat masks, specially designed for outdoor winter athletes, might protect against bronchoconstriction triggered by inhalation of cold and dry air.

CONCLUSION

EIA in elite athletes should be managed as in any individual with asthma, but the risk of developing tolerance to bronchodilators as well as doping aspects should always be taken into account.

Function and mechanisms of TSLP/TSLPR complex in asthma and COPD

Thymic stromal lymphopoietin (TSLP) is a key pro-allergic cytokine that has recently been linked to chronic airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD). High levels of TSLP were detected in bronchial mucosa of asthma and COPD patients suggesting TSLP's biological role beyond a signature 'Th2-favoring' or 'pro-allergic cytokine'. Besides inflammatory cells, airway structural cells produce and are targets of TSLP suggesting a potential autocrine loop that may have a profound effect on local inflammatory response and airway remodelling. This review sums up diverse mechanisms that mediate TSLP/TSLP receptor-signalling network in chronic airway diseases.

How can 1 + 1 = 3? β2-adrenergic and glucocorticoid receptor agonist synergism in obstructive airway diseases

For a long time it was believed that β(2)-adrenergic receptor agonists used in the treatment of obstructive airway diseases worked primarily on airway smooth muscle cells, causing relaxation, whereas glucocorticoids primarily improved airway function via their anti-inflammatory action, indicating that their clinical synergism occurred at the organism rather than the cellular level. However, it is now becoming clear that both drug classes can affect airway function at multiple levels, including an integrated effect on several cell types. This article summarizes data on the molecular interaction between the two receptor systems, particularly with relevance to phenomena of β(2)-adrenergic receptor desensitization and glucocorticoid insensitivity in the airways. These molecular interactions may contribute to the observed clinical synergism between both drug classes in the treatment of obstructive airway diseases.

The addition of long-acting beta-agonists to inhaled corticosteroids in asthma

PURPOSE OF REVIEW

although long-acting beta-agonists (LABAs) have been used for two decades, with many studies showing benefit versus increasing inhaled corticosteroid (ICS), controversy regarding safety has resulted in the United States Food and Drug Administration (FDA) recently mandating label changes restricting LABA use. This review addresses these safety concerns together with clinical studies and meta-analyses assessing the appropriate use of LABAs.

RECENT FINDINGS

effective use of LABAs requires sufficient ICS to control inflammation. Underuse of ICS, which is often manifest by exacerbations, may reflect undue emphasis on alleged steroid-sparing effects of LABAs. The FDA meta-analysis found that LABA with mandatory ICS was not associated with increased risks of serious adverse events. The role of LABA with ICS as initial therapy in steroid-naïve patients is debated, as is LABA use in children, with data indicating less benefit than in adults. The FDA recommendation that LABA be withdrawn once control is achieved remains problematic, as greater ICS reduction can be achieved when LABA is continued.

SUMMARY

the safe use of LABAs, which are clearly effective in many patients with moderate to severe asthma, requires high compliance with ICS therapy, which is best assured if ICS and LABA are provided in a single inhaler.

Steroids and bronchodilators for acute bronchiolitis in the first two years of life: systematic review and meta-analysis

OBJECTIVE

To evaluate and compare the efficacy and safety of bronchodilators and steroids, alone or combined, for the acute management of bronchiolitis in children aged less than 2 years.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Medline, Embase, Central, Scopus, PubMed, LILACS, IranMedEx, conference proceedings, and trial registers. Inclusion criteria Randomised controlled trials of children aged 24 months or less with a first episode of bronchiolitis with wheezing comparing any bronchodilator or steroid, alone or combined, with placebo or another intervention (other bronchodilator, other steroid, standard care).

REVIEW METHODS

Two reviewers assessed studies for inclusion and risk of bias and extracted data. Primary outcomes were selected by clinicians a priori based on clinical relevance: rate of admission for outpatients (day 1 and up to day 7) and length of stay for inpatients. Direct meta-analyses were carried out using random effects models. A mixed treatment comparison using a Bayesian network model was used to compare all interventions simultaneously.

RESULTS

48 trials (4897 patients, 13 comparisons) were included. Risk of bias was low in 17% (n = 8), unclear in 52% (n = 25), and high in 31% (n = 15). Only adrenaline (epinephrine) reduced admissions on day 1 (compared with placebo: pooled risk ratio 0.67, 95% confidence interval 0.50 to 0.89; number needed to treat 15, 95% confidence interval 10 to 45 for a baseline risk of 20%; 920 patients). Unadjusted results from a single large trial with low risk of bias showed that combined dexamethasone and adrenaline reduced admissions on day 7 (risk ratio 0.65, 0.44 to 0.95; number needed to treat 11, 7 to 76 for a baseline risk of 26%; 400 patients). A mixed treatment comparison supported adrenaline alone or combined with steroids as the preferred treatments for outpatients (probability of being the best treatment based on admissions at day 1 were 45% and 39%, respectively). The incidence of reported harms did not differ. None of the interventions examined showed clear efficacy for length of stay among inpatients.

CONCLUSIONS

Evidence shows the effectiveness and superiority of adrenaline for outcomes of most clinical relevance among outpatients with acute bronchiolitis, and evidence from a single precise trial for combined adrenaline and dexamethasone.

Beta-agonist-associated reduction in RGS5 expression promotes airway smooth muscle hyper-responsiveness

Although short-acting and long-acting inhaled β(2)-adrenergic receptor agonists (SABA and LABA, respectively) relieve asthma symptoms, use of either agent alone without concomitant anti-inflammatory drugs (corticosteroids) may increase the risk of disease exacerbation in some patients. We found previously that pretreatment of human precision-cut lung slices (PCLS) with SABA impaired subsequent β(2)-agonist-induced bronchodilation, which occurred independently of changes in receptor quantities. Here we provide evidence that prolonged exposure of cultured human airway smooth muscle (HuASM) cells to β(2)-agonists directly augments procontractile signaling pathways elicited by several compounds including thrombin, bradykinin, and histamine. Such treatment did not increase surface receptor amounts or expression of G proteins and downstream effectors (phospholipase Cβ and myosin light chain). In contrast, β-agonists decreased expression of regulator of G protein signaling 5 (RGS5), which is an inhibitor of G-protein-coupled receptor (GPCR) activity. RGS5 knockdown in HuASM increased agonist-evoked intracellular calcium flux and myosin light chain (MLC) phosphorylation, which are prerequisites for contraction. PCLS from Rgs5(-/-) mice contracted more to carbachol than those from WT mice, indicating that RGS5 negatively regulates bronchial smooth muscle contraction. Repetitive β(2)-agonist use may not only lead to reduced bronchoprotection but also to sensitization of excitation-contraction signaling pathways as a result of reduced RGS5 expression.

Annual change of respiratory functions in adult patients with asthma: the potential of antiasthma treatments for many years to repair irreversible changes of the airway

BACKGROUND

Little is known regarding annual changes of respiratory functions among patients with asthma after asthma symptoms enter remission.

OBJECTIVE

Annual changes of respiratory function and influence of patient characteristics and treatment variables on these changes were assessed in patients with adult asthma.

METHODS

Respiratory function (pre- and postbronchodilator forced expiratory volume in one second [FEV₁] and reversibility by short-acting β₂-agonist) and their changes were retrospectively investigated and relationships between these changes, after symptomatic remission, and patient characteristics and treatments were analyzed in adult outpatients with asthma who had undergone spirometry (including a reversibility test) ≥5 times in >5 years.

RESULTS

In patients ≥40 years old, or with disease duration ≥10 years or receiving treatment for severe asthma (steps 4-5, high-dose inhaled glucocorticosteroids, or addition of other medications), both pre- and postbronchodilator FEV₁ values were significantly lower (p < .05). Mean annual change of prebronchodilator FEV₁ (Δpre-FEV₁), annual change of postbronchodilator FEV₁ (Δpost-FEV₁), and annual change of reversibility (Δ reversibility) were -13.8 ± 59.7 ml/year, -25.9 ± 51.0 ml/year, and -0.56% ± 1.89%/year, respectively. Multivariate analysis after stepwise selection for variables in patient characteristics or treatments showed that disease duration ≥10 years contributed to annual improvement of respiratory functions (Δpre-FEV₁: odds ratio [OR] 1.57, 95% confidence interval [CI] 1.01-2.46; Δpost-FEV₁: OR 2.13, 95% CI 1.25-3.66), treatment with long-acting β₂-agonists (LABAs) contributed to annual improvement of respiratory function (Δpre-FEV₁: OR 2.05, 95% CI 1.23-3.16; Δpost-FEV₁: OR 1.78, 95% CI 1.11-2.87), and poor compliance contributed to annual worsening of respiratory functions (Δpre-FEV₁: OR 0.43, 95% CI 0.24-0.76; Δpost-FEV₁: OR 0.39, 95% CI 0.22-0.70). In addition, duration of disease ≥10 years and severe treatment (steps 4-5) from the beginning contributed to decreasing Δreversibility (OR 0.55, 95% CI 0.34-0.87 and OR 0.50, 95% CI 0.29-0.83, respectively).

CONCLUSIONS

Long-term treatments for asthma are expected to normalize respiratory dysfunction, which cannot be repaired in the short term. Treatment with LABAs and patient compliance may be the most important factors associated with annual improvement of respiratory functions.

Analytical construct of reversible desensitization of pituitary-testicular signaling: illustrative application in aging

Luteinizing hormone (LH) administered in pharmacological amounts downregulates Leydig cell steroidogenesis. Whether reversible downregulation of physiological gonadotropin drive operates in vivo is unknown. Most of the analytical models of dose-response functions that have been constructed are biased by the assumption that no downregulation exists. The present study employs a new analytical platform to quantify potential (but not required) pulsatile cycles of LH-testosterone (T) dose-response stimulation, desensitization, and recovery (pulse-by-pulse hysteresis) in 26 healthy men sampled every 10 min for 24 h. A sensitivity-downregulation hysteresis construct predicted marked hysteresis with a median time delay to LH dose-response inflection within individual T pulses of 23 min and with median T pulse onset and recovery LH sensitivities of 1.1 and 0.10 slope unit, respectively (P < 0.001). A potency-downregulation model yielded median estimates of one-half maximally stimulatory LH concentrations (EC(50) values) of 0.66 and 7.5 IU/l for onset and recovery, respectively (P < 0.001). An efficacy-downregulation formulation of hysteresis forecasts median LH efficacies of 20 and 8.3 ng·dl(-1)·min(-1) for onset and offset of T secretory burst, respectively (P = 0.002). Segmentation of the LH-T data by age suggested greater sensitivity, higher EC(50) (increased LH potency), and markedly (2.7-fold) attenuated LH efficacy in older individuals. Each of the three hysteresis models yielded a marked (P < 0.005) reduction in estimated model residual error compared with no hysteresis. In summary, model-based analyses allowing for (but not requiring) reversible pituitary-gonadal effector-response downregulation are consistent with a hypothesis of recurrent, brief cycles of LH-dependent stimulation, desensitization, and recovery of pulsatile T secretion in vivo and an age-associated reduction of LH efficacy. Prospective studies would be required to prove this aging effect.

Glucocorticoids for acute viral bronchiolitis in infants and young children

BACKGROUND

Previous systematic reviews have not shown clear benefit of glucocorticoids for acute viral bronchiolitis, but their use remains considerable. Recent large trials add substantially to current evidence and suggest novel glucocorticoid-including treatment approaches.

OBJECTIVES

To review the efficacy and safety of systemic and inhaled glucocorticoids in children with acute viral bronchiolitis.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, issue 4); MEDLINE (1950 to November 2009); EMBASE (1980 to Week 47 2009); LILACS (1982 to November 2009); Scopus® (1823 to November 2009); and IRAN MedEx (1998 to November 2009).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing short-term systemic or inhaled glucocorticoids versus placebo or another intervention in children < 24 months with acute bronchiolitis (first episode with wheezing). Our primary outcomes were: admissions by days 1 and 7 for outpatient studies; and length of stay (LOS) for inpatient studies. Secondary outcomes included clinical severity parameters, healthcare use, pulmonary function, symptoms, quality of life and harms.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data on study and participant characteristics, interventions and outcomes. We assessed risk of bias and graded strength of evidence. Inpatient and outpatient results were meta-analysed separately using random-effects models. We pre-specified subgroup analyses, including the combined use of protocolised bronchodilators.

MAIN RESULTS

We included 17 trials (2596 participants); only two had low overall risk of bias. Baseline severity, glucocorticoid schemes, comparators and outcomes were heterogeneous. Glucocorticoids did not significantly reduce outpatient admissions by days 1 and 7 when compared to placebo (pooled risk ratios (RRs) 0.92; 95% CI 0.78 to 1.08; and 0.86; 95% CI 0.7 to 1.06, respectively). There was no benefit in LOS for inpatients (mean difference -0.18 days; 95% CI -0.39 to 0.04). Unadjusted results from a large factorial low risk of bias RCT found combined high-dose systemic dexamethasone and inhaled epinephrine reduced admissions by day 7 (baseline risk of admission 26%; RR 0.65, 95% CI 0.44 to 0.95; number needed to treat 11, 95% CI 7 to 76), with no differences in short-term adverse effects. No other comparisons showed relevant differences in primary outcomes.

AUTHORS' CONCLUSIONS

Current evidence does not support a clinically relevant effect of systemic or inhaled glucocorticoids on admissions or length of hospitalization. Combined dexamethasone and epinephrine may reduce outpatient admissions, but results are exploratory and safety data limited. Future research should further assess the efficacy, harms and applicability of combined therapy.

Current concepts on the use of glucocorticosteroids and beta-2-adrenoreceptor agonists to treat childhood asthma

PURPOSE OF REVIEW

This article reviews current concepts regarding the clinical and scientific rationale for the combined use of glucocorticosteroids and beta-2-adrenoreceptor (beta2AR) agonists in the treatment of childhood asthma.

RECENT FINDINGS

Several studies have demonstrated that inhaled corticosteroids (ICS) and beta2AR agonists are the most effective medications for the management of asthma in children. Given substantial evidence of an increased clinical benefit when these agents are used together, new studies are being pursued to establish the efficacy and safety of this combinational therapy in infants and children. Ongoing research is also investigating the mechanisms of beta2AR and glucocorticosteroids signaling and their molecular interactions. This new knowledge will likely lead to novel therapeutic approaches to asthma control.

SUMMARY

There is increasing evidence demonstrating that the combination of long-acting beta2AR agonists and ICS may be more effective than high-dose ICS therapy alone in the management of children with uncontrolled asthma. In addition, the use of a single inhaler containing ICS and a quick-acting beta2AR agonist might be a convenient alternative to prevent and treat asthma exacerbations. Future investigations should be designed to more specifically evaluate the efficacy and safety of these therapies in the different asthmatic phenotypes of infants and children.