The mechanisms, diagnosis, and management of severe asthma in adults

Liposomal corticosteroids for the treatment of inflammatory disorders and cancer

Glucocorticoids (GC) are known for their potent immunosuppressive and anti-inflammatory properties. As a consequence, they have been extensively used for the treatment of many different diseases. Prolonged and/or high-dose GC therapy, however, generally comes with severe side effects, resulting not only from their very diverse mechanism(s) of action, but also from their relatively poor biodistribution. Drug delivery systems, and in particular liposomes, have been extensively used to enhance the biodistribution and the target site accumulation of GC, and to thereby improve the balance between their efficacy and their toxicity. Many different types of liposomes have been employed, and both local and systemic treatments have been evaluated. We here summarize the progress made in the use of liposomal GC formulations for the treatment of asthma, rheumatoid arthritis, multiple sclerosis and cancer, and we show that the targeted delivery of GC to pathological sites holds significant clinical potential.

Efficacy and safety of high-dose ciclesonide for the treatment of severe asthma

Asthma severity is classified according to the level of treatment required to control symptoms. Inhaled corticosteroids are the recommended first-line therapy for the treatment of persistent asthma, and when asthma remains uncontrolled, one option is to increase the inhaled corticosteroids dose. However, there is a concomitant risk of increasing local and systemic adverse events, which may impact patient adherence and physician prescribing practices. Ciclesonide is delivered as a prodrug, has high peripheral lung deposition and high protein-binding capabilities, and is rapidly eliminated from the systemic circulation. This article reviews the use of high-dose ciclesonide in patients with severe asthma and considers whether the pharmacology of ciclesonide translates into it being an efficacious and well-tolerated option for patients requiring a step-up in their asthma treatment.

Profile of patients treated with omalizumab in routine clinical practice in Spain

BACKGROUND

Omalizumab is indicated in patients with severe allergic asthma not controlled by high-dose inhaled glucocorticoids and long-acting beta-agonists. Few data are available on the profile of patients treated with this drug in routine clinical practice in Spain.

OBJECTIVE

To describe the profile of patients with severe allergic asthma treated with omalizumab and the course of the disease after a period of treatment.

METHODS

Retrospective, multicentre study, recording the data on patients of either sex and ≥12 years with uncontrolled severe allergic asthma, previously treated with omalizumab. Data were evaluated in relation to pulmonary function, symptoms, quality of life, and concomitant anti-asthma treatment before the prescription of omalizumab and at the time of the study visit.

RESULTS

214 patients were evaluable (mean age=48.2±17.7 years; mean age at the time of diagnosis=26.6±16.5 years). 90.7% had experienced exacerbations the year before receiving omalizumab, and the mean total IgE level was 273±205.4IU/ml. The mean monthly dose was 380.5±185.4mg. Compared with the baseline situation, differences were observed after treatment with omalizumab in mean FEV1 (62.7±15.9% vs. 70.8±18.7%), in the proportion of patients requiring oral corticosteroids (47.7% vs. 14.0%), and in the ACQ and AQLQ scores. 32.7% of the patients received doses not recommended by the Summary of Product Characteristics (SPC).

CONCLUSIONS

Profile of asthmatic patients treated with omalizumab predominantly corresponds to uncontrolled severe asthma cases, in accordance with SPC's indications. The results of the study suggest a favourable clinical course similar to that observed in other studies.

Clinical consequences of targeting IL-17 and TH17 in autoimmune and allergic disorders

The TH17 lineage of T cells and its canonical cytokine IL-17 have been the focus of many recent studies in autoimmune, allergic, and infectious disease. In this review, we will briefly discuss the current knowledge about the role of these cells and IL-17 in a spectrum of disorders. It is clear that IL-17 plays pathogenic roles in certain conditions while the same pathway is critically important to immunity in others. Targeting of TH17 cells or IL-17 therapeutically may impart many benefits, but this approach is not without potentially serious implications regarding host defense. These issues will be discussed herein as we evaluate pharmacological approaches targeting this pathway that are just beginning to be fully tested in human disease.

Rationale and clinical results of inhibiting interleukin-5 for the treatment of severe asthma

Severe asthma is responsible for considerable morbidity and a high proportion of the healthcare costs attributable to asthma. Management is not straightforward as the clinical, pathological and physiological features are heterogeneous and the relationships between these features are poorly understood. In recent years significant progress has been made in understanding this heterogeneity and eosinophilic asthma has emerged as a potentially clinically important phenotype because treatment with monoclonal antibodies against IL-5 is effective. This has required a change in our understanding of the role of eosinophilic airway inflammation in airways disease and the developments of reliable biomarkers of eosinophilic airway inflammation. We will review these developments and describe the clinical experience so far with treatment with monoclonal antibiotics against IL-5.

Non-anticoagulant derivatives of heparin for the management of asthma: distant dream or close reality?

INTRODUCTION

Approximately 300 million people worldwide are currently affected by asthma. Improvements in the understanding of the mechanisms involved in such inflammatory airway disorders has led to the recognition of new therapeutic approaches. Heparin, a widely used anticoagulant, has been shown to be beneficial in the management of asthma. It belongs to the family of highly sulphated polysaccharides referred to as glycosaminoglycans, containing a heterogeneous mixture of both anticoagulant and non-anticoagulant polysaccharides. Experimental findings have suggested that heparin has potential anti-asthmatic properties owing to the ability of its non-anticoagulant oligosaccharides to bind and modulate the activity of a wide range of biological molecules involved in the inflammatory process.

AREAS COVERED

This review focuses on the potential mechanisms of action and clinical application of heparin as an anti-inflammatory agent for the management of asthma.

EXPERT OPINION

Heparin may play a significant role in the management of asthma. However, these properties are often hindered by the presence of anticoagulant oligosaccharides, which possess a significant risk of bleeding. Therefore, its therapeutic potential must be explored using well-designed clinical studies that focus on identifying and isolating the anti-inflammatory oligosaccharides of heparin and further elucidating the structure and mechanisms of actions of these non-anticoagulant oligosaccharides.

Cluster analysis identifies characteristic phenotypes of asthma with accelerated lung function decline

OBJECTIVE

While the majority of individuals with asthma retain normal lung function over time, some exhibit accelerated lung function decline. Preservation of lung function is an important aspect of asthma management. Whether the asthma guidelines can prevent lung function decline remains controversial. This study was performed to determine the distribution of asthmatic subjects with greater lung function decline and to identify characteristic clinical features of such subjects treated in accordance with clinical guidelines by using hierarchical cluster analysis.

METHODS

Eighty-six asthmatic subjects without a history of smoking were assessed with respect to eight variables selected from clinical phenotypes by using step-wise multiple regression analysis. Hierarchical cluster analysis using Ward's method generated a dendrogram for estimation of the number of clusters within the population and the differences between them.

RESULTS

Three distinct clusters were identified. Cluster 1 (n = 40) comprised women with late-onset asthma. Cluster 2 (n = 17) comprised subjects with early-onset asthma, atopy and long disease duration. Cluster 3 (n = 29) predominantly comprised older men who had late-onset asthma, a lower prevalence of exacerbation and a lower predicted % forced expiratory volume in 1 s (FEV1) at baseline. Subjects in cluster 3 showed a mean decline in FEV1 of 69 mL/year, which was the greatest lung function decline among the three clusters.

CONCLUSION

We identified a subgroup of patients with accelerated lung function decline despite appropriate asthma treatment based on guidelines constructed by using subjective symptoms.

What is asthma? Pathophysiology, demographics, and health care costs

Asthma is an obstructive pulmonary disorder with exacerbations characterized by symptoms of shortness of breath, cough, chest tightness, and/or wheezing. Symptoms are caused by chronic airway inflammation. There are multiple cell types and inflammatory mediators involved in its pathophysiology. The airway inflammation is frequently mediated by Th2 lymphocytes, whose cytokine secretion leads to mast cell stimulation, eosinophilia, leukocytosis, and enhanced B-cell IgE production. Although various genes have been identified as likely contributors to asthma development, asthma is largely environmentally triggered and has a multifactorial cause. Asthma is extremely common, especially in poor, urban environments. Asthma is the third most common reason for pediatric hospitalizations.

Attenuation of allergic airway inflammation in a murine model of asthma by Licochalcone A

CONTEXT

Licochalcone A (Lico A) is a major and biogenetically characteristic chalcone isolated from the root of Xinjiang liquorice, Glycyrrhiza inflata.

OBJECTIVE

We focused on investigating whether Lico A possesses distinct anti-inflammatory activity on a non-infectious mouse model of asthma, and we aimed to elucidate its involvement with the mitogen-activated protein kinases pathway.

METHODS

BALB/c mice that were sensitized and challenged to ovalbumin (OVA) were treated with Lico A (50 mg/kg) 1 h before they were challenged with OVA.

RESULTS

Our study demonstrated that Lico A may effectively inhibit the increase in T-helper type 2 cytokines, such as interleukin (IL)-4, IL-5 and IL-13 in bronchoalveolar lavage fluid, and reduced serum levels of OVA-specific IgE and IgG. Furthermore, Lico A substantially inhibited OVA-induced eosinophilia in lung tissue and mucus hyper-secretion by goblet cells in the airway. Meanwhile, pretreatment with Lico A resulted in a significant reduction in mRNA expression of acidic mammalian chitinase, chitinase 3-like protein 4 (Ym2), E-selectin, Muc5ac, CCL11 and CCR3 in lung tissues and airway hyper-responsiveness to methacholine.

CONCLUSIONS

These findings suggest that Lico A may effectively delay the progression of airway inflammation and could be used as a therapy for patients with allergic airway inflammation.

Receptor for advanced glycation end products and its involvement in inflammatory diseases

The receptor for advanced glycation end products (RAGE) is a transmembrane receptor of the immunoglobulin superfamily, capable of binding a broad repertoire of ligands. RAGE-ligands interaction induces a series of signal transduction cascades and lead to the activation of transcription factor NF-κB as well as increased expression of cytokines, chemokines, and adhesion molecules. These effects endow RAGE with the role in the signal transduction from pathogen substrates to cell activation during the onset and perpetuation of inflammation. RAGE signaling and downstream pathways have been implicated in a wide spectrum of inflammatory-related pathologic conditions such as arteriosclerosis, Alzheimer's disease, arthritis, acute respiratory failure, and sepsis. Despite the significant progress in other RAGE studies, the functional importance of the receptor in clinical situations and inflammatory diseases still remains to be fully realized. In this review, we will summarize current understandings and lines of evidence on the molecular mechanisms through which RAGE signaling contributes to the pathogenesis of the aforementioned inflammation-associated conditions.

Phenotype properties and status of corticosteroid resistance among patients with uncontrolled asthma

BACKGROUND

Control cannot be achieved in some asthmatics although optimal monitoring and treatment is administered. Glucocorticoid (GC) resistance is one of the reasons of poor asthma control. We aimed to investigate GC resistance by lymphocyte proliferation suppression test (LPST) in uncontrolled asthmatics.

METHODS

After assessing asthma control level of 77 asthmatics their treatment was adjusted upon GINA guidelines. They were followed-up for three to six months and the patients who remained uncontrolled were accepted as uncontrolled patients. Steroid resistance test (SRT) was applied to them (7-14 days oral prednisolone) and the patients who were still uncontrolled and/or had a FEV1 increase <15% after SRT were assessed as the "case group" while the remaining composed the "control group". Optimal treatment was adjusted and at the end of a follow-up period LPST was performed to both groups.

RESULTS

Fourteen of the case (n=22) and four (n=8) of the control groups could be evaluated by LPST. Proliferated lymphocytes were observed to be significantly suppressed in all dexamethasone concentrations in the control group (p=0.001). However, in the case group LPST was positive only at 10(-6) and 10(-4) concentrations although statistically not significant (p=0.147). There was no significant relationship between clinically GC resistance and LPST positivity (p=0.405).

CONCLUSION

We determined that in vitro responses to the GCs were significantly declined in the uncontrolled asthma cases. An SRT alone does not seem to be very sensitive for evaluating GC sensitivity, LPST may be performed for demonstrating GC responsiveness in asthmatic patients in addition to SRT.

Inhaled and systemic corticosteroid response in severe asthma assessed by alveolar nitric oxide: a randomized crossover pilot study of add-on therapy

AIMS

Alveolar nitric oxide (CA(NO)) is a potential biomarker of small airway inflammation. We investigated effects on CA(NO) of the addition of coarse and fine particle inhaled corticosteroids to standard therapy in severe asthma.

METHODS

Severe asthmatics taking ≥1600 µg day(-1) budesonide or equivalent performed a randomized open-label crossover study. Subjects with FEV(1) < 80%, gas trapping and CA(NO) ≥2 ppb entered a 6 week dose-ramp run-in of fluticasone/salmeterol(FPSM) 250/50 µg twice daily for 3 weeks, then 500/50 µg twice daily for 3 weeks. Patients then received additional HFA-beclomethasone diproprionate (BDP) 200 µg twice daily or FP 250 µg twice daily for 3 weeks in a crossover. Participants then received prednisolone(PRED) 25 mg day(-1) for 1 week. Nitric oxide, lung function, mannitol challenge, systemic inflammatory markers and urinary cortisol were measured.

RESULTS

Fifteen completed per protocol: mean (SD) age 51 (12) years, FEV(1) 58 (13)% predicted, residual volume 193 (100)% predicted and mannitol(PD10) 177 (2.8) µg. There was no significant difference between FPSM and add-on therapy for CA(NO). FPSM/BDP and FPSM/PRED suppressed broncial flux (Jaw(NO)) and FE(NO) compared with FPSM alone, but there was no significant difference between FPSM/BDP and FPSM/FP. ECP, e-selectin and ICAM-1 were suppressed by FPSM/PRED compared with FPSM and FPSM/FP but not FPSM/BDP. Plasma cortisol was significantly suppressed by FPSM/PRED.

CONCLUSION

In severe asthma, CA(NO) is insensitive to changes in dose and delivery of inhaled corticosteroids and is not suppressed by systemic corticosteroids. Additional inhaled HFA-BDP reduced FE(NO) and Jaw(NO) without adrenal suppression. There was a trend to reduction in FE(NO) and Jaw(NO) with additional FP but this did not reach statistical significance. PRED reduced FE(NO) and Jaw(NO) with suppression of systemic inflammatory markers and urinary cortisol.

Depressive symptomatology, quality of life and disease control among individuals with well-characterized severe asthma

OBJECTIVES

A thorough examination of the relationship of asthma severity and control with symptoms of depression is needed to identify groups of asthmatics at high risk for poor disease control outcomes. This study examines the relationship of symptoms of depression with severity and control in a well-characterized cohort of asthmatics and healthy controls.

METHODS

Depressive symptoms and quality of life were assessed using the Beck Depression Inventory. Disease control was measured by a composite index incorporating symptoms, activity limitation and rescue medication use.

RESULTS

Individuals with asthma (n = 91) reported more symptoms of depression than controls (n = 36; p < 0.001). Those with severe asthma (n = 49) reported more symptoms of depression (p = 0.002) and poorer asthma control (p < 0.0001) than those with not severe asthma. Worse asthma control was associated with more depressive symptoms in severe (r = 0.46, p = 0.002) but not in not severe (r = 0.13, p = 0.40) asthmatics. The relationship of symptoms of depression among severe asthmatics was attenuated by disease control. Exploratory analyses identified specific disease symptom characteristics, as opposed to exacerbations, as associated with symptoms of depression.

CONCLUSIONS

Among individuals with severe asthma, increased symptom burden is positively associated with risk for co-morbid depression. These findings point to a need for regular mood disorder screenings and treatment referrals among this group. Further research is warranted to examine whether treatment of comorbid depression improves treatment adherence and asthma-related quality of life.

Detection of exacerbations in asthma based on electronic diary data: results from the 1-year prospective BIOAIR study

BACKGROUND

Objective measures are required that may be used as a proxy for exacerbations in asthma. The aim was to determine the sensitivity and specificity of electronic diary data to detect severe exacerbations (SEs) of asthma. A secondary aim was to identify phenotypic variables associated with a higher risk of exacerbation.

METHODS

In the BIOAIR study, 169 patients with asthma (93 severe (SA); 76 mild to moderate (MA)) recorded lung function, symptoms and medication use in electronic diaries for 1 year. Data were analysed using receiver-operator characteristics curves and related to physician-diagnosed exacerbations. Medical history and baseline clinical data were used to assess risk of exacerbation.

RESULTS

Of 122 physician-diagnosed exacerbations, 104 occurred in the SA group (1.1 per patient/year), 18 in the MA group (0.2 per patient/year) and 63 were severe using American Thoracic Society/European Respiratory Society criteria. During exacerbations, peak expiratory flow (PEF) and forced expiratory volume in 1 s significantly decreased, whereas day and night symptoms significantly increased. An algorithm combining a 20% decrease in PEF or a 20% increase in day symptoms on 2 consecutive days was able to detect SEs with 65% sensitivity and 95% specificity. The strongest risk factors for SEs were low Asthma Control Questionnaire score, sputum eosinophils ≥ 3%, body mass index >25 and low quality of life (St George's Respiratory Questionnaire), with ORs between 3.61 and 2.22 (p<0.05).

CONCLUSIONS

Regular electronic monitoring of PEF and asthma symptoms provides an acceptable sensitivity and specificity for the detection of SEs and may be suitable for personal internet-based monitoring of asthma control.

Intratracheal transplantation of bone marrow-derived mesenchymal stem cells reduced airway inflammation and up-regulated CD4⁺CD25⁺ regulatory T cells in asthmatic mouse

Mesenchymal stem cells attenuate the severity of lung injury due to their immunomodulatory properties. The effect of bone marrow-derived mesenchymal stem cells on asthma is seldom reported. We have examined the effect of BMSCs on airway inflammation in asthma. Forty female BALB/c mice were equally randomised into PBS group, BMSCs treatment group, BMSCs control group and asthmatic group. Reactivity of the airway to acetylcholine was measured by barometric plethysmography. Cytokine profiles of bronchoalveolar lavage fluid and serum were determined by enzyme-linked immunosorbent assay. Morphometric analysis was done with haematoxylin and periodic-acid Schiff staining. Engraftment of BMSCs in asthmatic mice significantly decreased the number of eosinophils and mononuclear cells in bronchoalveolar lavage fluid and the airway (P < 0.05). Both goblet cell hyperplasia and responsiveness to acetylcholine were significantly reduced in BMSCs treatment groups. Moreover, BMSCs engraftment caused significant increases the ratio of Treg in pulmonary lymph node and interleukin-10 (IL-10) and interleukin-12 levels in BALF and serum. We conclude that BMSCs engraftment ameliorated airway inflammation and improved lung function in asthmatic mouse and the protective effect might be mediated by upregulating Treg and partly involved with increasing IL-10.

Controlled exposure to diesel exhaust causes increased nitrite in exhaled breath condensate among subjects with asthma

OBJECTIVE

To determine whether oxidative/nitrosative stress plays a role in the acute effects of diesel exhaust (DE) on subjects with asthma.

METHODS

In this crossover study, 16 subjects with mild to moderate asthma were exposed to clean filtered air or diluted DE (300 μg/m as PM2.5) for 1 hour with intermittent exercise.

RESULTS

Airway hyperreactivity increased 24 hours after exposure to DE compared with clean filtered air (PC20, 14.9 mg/mL vs 19.7 mg/mL; P = 0.012). Nitrite in exhaled breath condensate was elevated immediately after diesel exposure (P = 0.052) and remained elevated 4 and 24 hours after exposure.

CONCLUSIONS

After exposure to DE, subjects with asthma demonstrated increased airway hyperreactivity and obstruction. Increased nitrite in exhaled breath condensate, in the absence of increased exhaled nitric oxide, suggests a noninflammatory oxidative stress mechanism by which DE affects the lung.

Th17 responses in chronic allergic airway inflammation abrogate regulatory T-cell-mediated tolerance and contribute to airway remodeling

The role of T-helper type 17 (Th17) responses in airway remodeling in asthma is currently unknown. We demonstrate that both parenteral and mucosal allergen sensitization, followed by allergen inhalation, leads to Th17-biased lung immune responses. Unlike Th17 cells generated in vitro, lung Th17 cells did not produce tumor necrosis factor-α or interleukin (IL)-22. Eosinophilia predominated in acute inflammation, while neutrophilia and IL-17 increased in chronic disease. Allergen-induced tolerance involved Foxp3-, Helios-, and glycoprotein-A repetitions predominant-expressing regulatory T cells (Treg) and IL-10/interferon-γ priming. This Treg phenotype was altered in inflamed lungs and abrogated by inhalation of IL-17. Using Th17-deficient mice with genetic disruption of gp130 in T cells, we showed that Th17 cells induce airway remodeling independent of the Th2 response. All-trans retinoic acid administration ameliorated Th17-mediated disease and increased Treg activity, while dexamethasone inhibited eosinophilia but not neutrophilia, and enhanced Th17 development in vitro. Targeting the Th17/Treg axis might therefore be therapeutic in neutrophilic and glucocorticoid-refractory asthma.

Severe asthma: an expanding and mounting clinical challenge

Although all patients with asthma have variable airflow obstruction, airway inflammation, and bronchial hyperresponsiveness, some have disease that is severe in many aspects: persistent airflow obstruction, ongoing symptoms, increased frequency of exacerbations, and, most importantly, a diminished response to medications. A number of definitions have emerged to characterize the clinical features of severe asthma, but a central feature of this phenotype is the need for high doses of medications, especially corticosteroids, in attempts to achieve disease control. The prevalence of severe asthma is also undergoing reevaluation from the usual estimate of 10% to larger numbers on the basis of medication needs and the lack of disease control achieved. At present, the underlying mechanisms of severe asthma are not established but likely reflect a heterogeneous pattern, rather than a single unifying process. Guideline-directed treatment for severe asthma has limits with usual approaches centered on high doses of inhaled corticosteroids, long-acting β-agonists, and trials with omalizumab, the monoclonal antibody to IgE. With the development of approaches to recognize asthma phenotypes with distinct pathogenesis and hence unique therapeutic targets, it is hoped that a personalized strategy in treatment directed toward disease-specific features will improve outcomes for this high-risk, severely affected population of patients.

Monoclonal Anti-TNF-α Antibodies for Severe Steroid-Dependent Asthma: A Case Series

BACKGROUND

Refractory asthma represents an important condition, with considerable morbidity and mortality. Tumor necrosis factor α (TNF-α) is a potential target for treatment of severe asthma. However, controlled studies have shown controversial results and the risk-benefit profile of TNF-blocking agents is still debated.

OBJECTIVES

To describe the effect of infliximab on asthma control in patients with severe, uncontrolled, steroid-dependent asthma.

METHODS

From 2007 to 2010, 7 patients received infliximab in our center. All had severe refractory asthma, with frequent severe exacerbations and hospitalizations in the intensive care unit despite maximal inhaled treatment, daily oral steroids and omalizumab treatment.

RESULTS

Asthma control improved in the 6 patients who received infliximab for at least 3 months. Oral steroids could be stopped in 4 and the frequency of exacerbations and hospitalizations was greatly reduced, especially for the 3 patients with brittle asthma. Two patients showed severe adverse effects (bacterial pneumonia and extension of spreading melanoma). Three patients have received infliximab for more than 2 years, with good tolerance.

CONCLUSION

This case series suggests that anti-TNF-α drugs may improve the condition of a subgroup of patients with severe steroid-refractory asthma, with a favourable risk-benefit profile for most, considering asthma severity, occurrence of life-threatening exacerbations and complications of long-term oral steroids. Specific controlled trials of this subgroup are warranted.

Corticosteroid insensitivity is reversed by formoterol via phosphoinositide-3-kinase inhibition

BACKGROUND AND PURPOSE

Patients with chronic obstructive pulmonary disease (COPD) show a poor response to corticosteroids, which has been linked to oxidative stress. Here we show that the long-acting β(2) -agonist formoterol (FM) reversed corticosteroid insensitivity under oxidative stress via inhibition of phosphoinositide-3-kinase (PI3K) signalling.

EXPERIMENTAL APPROACH

Responsiveness to corticosteroids dexamethasone (Dex), budesonide (Bud) and fluticasone propionate (FP) was determined, as IC(50) values on TNF-α-induced interleukin 8 release, in U937 monocytic cell line treated with hydrogen peroxide (H(2) O(2) ) or peripheral blood mononuclear cells (PBMCs) from patients with COPD or severe asthma.

KEY RESULTS

PBMCs from severe asthma and COPD were less sensitive to Dex compared with those from healthy subjects. Both FM (10(-9)  M) and salmeterol (SM, 10(-8)  M) reversed Dex insensitivity in severe asthma, but only FM restored Dex sensitivity in COPD. Although H(2) O(2) exposure decreased steroid sensitivity in U937 cells, FM restored responsiveness to Bud and FP while the effects of SM were weaker. Additionally, FM, but not SM, partially inhibited H(2) O(2) -induced PI3Kδ-dependent (PKB) phosphorylation. H(2) O(2) decreased SM-induced cAMP production in U937 cells, but did not significantly affect the response to FM. The reduction of SM effects by H(2) O(2) was reversed by pretreatment with LY294002, a PI3K inhibitor, or IC87114, a PI3Kδ inhibitor.

CONCLUSION AND IMPLICATIONS

FM reversed oxidative stress-induced corticosteroid insensitivity and decreased β(2) adrenoceptor-dependent cAMP production via inhibition of PI3Kδ signalling. FM will be more effective than SM, when combined with corticosteroids, for the treatment of respiratory diseases under conditions of high oxidative stress, such as in COPD.

Application of metabolomics approaches to the study of respiratory diseases

Metabolomics is the global unbiased analysis of all the small-molecule metabolites within a biological system, under a given set of conditions. These methods offer the potential for a holistic approach to clinical medicine, as well as improving disease diagnosis and understanding of pathological mechanisms. Respiratory diseases including asthma and chronic obstructive pulmonary disorder are increasing globally, with the latter predicted to become the third leading cause of global mortality by 2020. The root causes for disease onset remain poorly understood and no cures are available. This review presents an overview of metabolomics followed by in-depth discussion of its application to the study of respiratory diseases, including the design of metabolomics experiments, choice of clinical material collected and potentially confounding experimental factors. Particular challenges in the field are presented and placed within the context of the future of the applications of metabolomics approaches to the study of respiratory diseases.

Disabling inflammatory pathways with biologics and resulting clinical outcomes in severe asthma

INTRODUCTION

Patients with severe asthma have a significant unmet need with persistent symptoms and/or frequent exacerbations despite high intensity treatment. These severe unrelenting symptoms have a huge impact on heathcare resources due to frequent hospital admissions and requirement for intensive and expensive medications. There is a compelling need for more effective and safer therapies to help severe asthma sufferers to achieve adequate control of their disease.

AREAS COVERED

Expanding knowledge of innate and adaptive immune responses has led to development of new biologic approaches for severe asthma. Here, the authors will review the existing efficacy and safety data from clinical trials of some of the new biologic therapies that are in development for severe asthma. Their specific role in distinctively targeted subpopulations of severe asthmatics will be also discussed.

EXPERT OPINION

Defining and phenotyping severe asthma patients will become increasingly important as some patients who were previously classified as having severe asthma may become well-controlled with a targeted phenotype-specific treatment. However, pharmacoeconomic concerns should also be taken into account given the elevated acquisition costs of recombinant human monoclonals and of the diagnostic screening procedures for the identification of potential responders.

The adult asthmatic

Asthma in the adult patient is a complex clinical syndrome. Multiple patient phenotypes and subphenotypes exist that contribute to disease heterogeneity. Whether adult asthma begins in utero, develops in childhood, or manifests for the first time in adulthood is not completely understood, nor are the mechanisms fully delineated. In this chapter, we update definitions that apply to this group, emphasize epidemiologic factors and pathogenic mechanisms, diagnosis, therapeutic options, and controversies regarding drug safety. Finally, we provide a brief discussion of biomarker technologies and novel therapies with the potential to impact adult-onset asthma outcomes.

Bronchial thermoplasty: a new treatment paradigm for severe persistent asthma

Patients with severe asthma represent only a minority of the total asthma population; however, they account for the majority of the mortality, morbidity, and health care-related cost of this chronic illness. Bronchial thermoplasty is a novel treatment modality that employs radiofrequency energy to alter the smooth muscles of the airways. This therapy represents a radical change in our treatment paradigm from daily repetitive dosing of medications to a truly long-term and potentially permanent attenuation of perhaps the most feared component of asthma--smooth muscle-induced bronchospasm. A large, multicentered, double-blinded, randomized controlled trial employed the unprecedented (but now industry standard for bronchoscopic studies) approach of using sham bronchoscopy as a control. It demonstrated that bronchial thermoplasty is safe, improved quality of life, and decreased frequency of severe exacerbations in the treatment group compared to the control group. Although the mechanism of action of bronchial thermoplasty is not currently completely understood, it should be considered as a valid and potentially valuable option for patients who have severe persistent asthma and who remain symptomatic despite inhaled corticosteroids and long-acting beta-2 agonists. Such patients should however be carefully evaluated at centers with expertise in managing severe asthma patients and with physicians who have experience with this promising new treatment modality.

Do small airway abnormalities characterize asthma phenotypes? In search of proof

The role of small airway abnormalities in asthma pathogenesis has been extensively studied and debated for several decades. However, whether or not small airway abnormalities play a relevant role in specific phenotypes of asthmatic patients and contribute to clinical presentation is largely unknown. In the present review, we evaluated available data on the role of small airways in severe asthma, with a further focus on asthma in smokers and asthma in the elderly. These phenotypes are characterized by a poor response to treatment and they can represent a model of greater small airway impairment. In severe asthmatics, small airway involvement has been shown through evidence of both distal inflammation and of increased air trapping. The few available data on asthmatics who smoke, and elderly asthmatics, similarly suggests that small airway abnormalities contribute to the pathogenesis of the disease. In this perspective, there could be a rationale for specifically assessing small airway impairment in these patients and for clinical studies evaluating whether pharmacological approaches targeting the more peripheral airways result in clinical benefits beyond conventional therapy.

Dehydroxymethylepoxyquinomicin (DHMEQ), a novel NF-kappaB inhibitor, inhibits allergic inflammation and airway remodelling in murine models of asthma

BACKGROUND

Dehydroxymethylepoxyquinomicin (DHMEQ) is a newly developed compound that inhibits nuclear factor κB activation and is reported to ameliorate animal models of various inflammatory diseases without significant adverse effects. Because nuclear factor κB is a transcription factor that plays a critical role in the pathophysiology of asthma, DHMEQ may be of therapeutic benefit in asthma.

OBJECTIVE

The purpose of this study was to evaluate the effects of DHMEQ on airway inflammation and remodelling in murine models of asthma.

METHODS

The BALB/c mice were sensitized and then challenged acutely or chronically with ovalbumin and administered DHMEQ intraperitoneally before each challenge. Inflammation of airways, lung histopathology and airway hyper responsiveness to methacholine challenge were evaluated. In addition, the effect of DHMEQ on production of cytokines and eotaxin-1 by murine splenocytes, human peripheral blood mononuclear cells and bronchial epithelial cells was investigated.

RESULTS

Airway hyper responsiveness was ameliorated in both acutely and chronically challenged models by treatment with DHMEQ. DHMEQ significantly reduced eosinophilic airway inflammation and levels of Th2 cytokines in bronchoalveolar lavage fluid in the acute model. It also inhibited parameters of airway remodelling including mucus production, peribronchial fibrosis and the expression of α-smooth muscle actin. Moreover, the production of Th2 cytokines from murine splenocytes and human peripheral blood mononuclear cells and the production of eotaxin-1 by bronchial epithelial cells were inhibited by DHMEQ.

CONCLUSIONS AND CLINICAL RELEVANCE

These results indicate that DHMEQ inhibits allergic airway inflammation and airway remodelling in murine models of asthma. DHMEQ may have therapeutic potential in the treatment of asthma.

Inflammation in COPD: implications for management

Chronic obstructive pulmonary disease (COPD) is recognized by the Global Initiative for Chronic Obstructive Lung Disease guidelines as an inflammatory disease state, and treatment rationales are provided accordingly. However, not all physicians follow or are even aware of these guidelines. Research has shown that COPD inflammation involves multiple inflammatory cells and mediators and the underlying pathology differs from asthma inflammation. For these reasons, therapeutic agents that are effective in asthma patients may not be optimal in COPD patients. COPD exacerbations are intensified inflammatory events compared with stable COPD. The clinical and systemic consequences believed to result from the chronic inflammation observed in COPD suggest that inflammation intensity is a key factor in COPD and exacerbation severity and frequency. Although inhaled corticosteroids are commonly used and are essential in asthma management, their efficacy in COPD is limited, with only a modest effect at reducing exacerbations. The importance of inflammation in COPD needs to be better understood by clinicians, and the differences in inflammation in COPD versus asthma should be considered carefully to optimize the use of anti-inflammatory agents.

Identification of subtypes of refractory asthma in Korean patients by cluster analysis

BACKGROUND

Refractory asthma, a subtype of asthma with uncontrolled symptoms despite antiasthma medications, is a heterogeneous syndrome with variable clinical features, presumably different etiologies, and pathophysiological mechanisms. The heterogeneity of refractory asthma, however, is poorly understood. We aimed to characterize refractory asthma and to improve our understanding of the heterogeneity of refractory asthma patients.

METHODS

We identified refractory asthma patients (n = 96) as defined by the American Thoracic Society's criteria from a cohort of Korean asthma patients (n = 2,187). Then, cluster analysis was conducted to classify subtypes of refractory asthma.

RESULTS

Among the study group, 4.4 % (n = 96) of all asthma patients had refractory asthma. Cluster analysis identified four distinct groups of refractory asthma. Age at onset was younger in clusters 1 and 2 than in clusters 3 and 4. Patients in cluster 1 had the most well-preserved pulmonary function; patients in cluster 2 had a female predominance and the most severe airway obstruction; patients in cluster 3 were mostly female and had the most enhanced bronchial hyperresponsiveness; and patients in cluster 4 were most male and tended to be cigarette smokers.

CONCLUSIONS

The current results suggest that refractory asthma is a heterogeneous syndrome and could be classified into four subtypes. Underlying pathogenesis and therapeutic approaches may differ for the different subtypes and further research is needed.

Transforming growth factor-beta promotes rhinovirus replication in bronchial epithelial cells by suppressing the innate immune response

Rhinovirus (RV) infection is a major cause of asthma exacerbations which may be due to a deficient innate immune response in the bronchial epithelium. We hypothesized that the pleiotropic cytokine, TGF-β, influences interferon (IFN) production by primary bronchial epithelial cells (PBECs) following RV infection. Exogenous TGF-β₂ increased RV replication and decreased IFN protein secretion in response to RV or double-stranded RNA (dsRNA). Conversely, neutralizing TGF-β antibodies decreased RV replication and increased IFN expression in response to RV or dsRNA. Endogenous TGF-β₂ levels were higher in conditioned media of PBECs from asthmatic donors and the suppressive effect of anti-TGF-β on RV replication was significantly greater in these cells. Basal SMAD-2 activation was reduced when asthmatic PBECs were treated with anti-TGF-β and this was accompanied by suppression of SOCS-1 and SOCS-3 expression. Our results suggest that endogenous TGF-β contributes to a suppressed IFN response to RV infection possibly via SOCS-1 and SOCS-3.

Bronchial thermoplasty for severe asthma

PURPOSE OF REVIEW

Bronchial thermoplasty, which involves the delivery of radio frequency energy to the airways to reduce airway smooth muscle mass, has been recently introduced for the treatment of severe asthma. This review summarizes the preclinical development, efficacy and adverse effects of bronchial thermoplasty. In addition, the potential mechanisms of action and place in management of severe asthma are discussed.

RECENT FINDINGS

The efficacy and adverse profile of bronchial thermoplasty has been assessed in three randomized controlled trials, the first two of which showed clinical benefits of bronchial thermoplasty compared with usual care in patients with moderate or severe asthma. The third trial reports the results of a comparison with sham bronchial thermoplasty in 288 adults with severe asthma. Bronchial thermoplasty improved asthma quality of life questionnaire scores compared with sham bronchial thermoplasty; in the posttreatment period, there were fewer severe exacerbations and emergency department visits. Bronchial thermoplasty causes short-term increases in asthma-related morbidity. Follow-up data to date support the long-term safety of the procedure.

SUMMARY

Bronchial thermoplasty has a role in the management of patients with severe asthma who have uncontrolled symptoms despite current therapies. Future studies need to identify factors that predict a beneficial clinical response.

Monitoring free serum IgE in severe asthma patients treated with omalizumab

BACKGROUND

Benefit of treatment with the monoclonal anti-IgE-antibody omalizumab in severe IgE-dependent asthma requires a significant reduction of serum free IgE concentrations. It is unclear if monitoring free serum IgE is clinically meaningful once omalizumab treatment is initiated.

METHODS

Free IgE and omalizumab serum concentrations were quantified in 22 patients with severe asthma (68% female, 47 ± 11 yrs, mean (±SD) pre-bronchodilator FEV(1) 62 ± 13%, baseline mean (±SEM) free serum IgE 652 ± 136 ng/ml) treated with omalizumab for 4 months using a Recovery-ELISA.

RESULTS

Omalizumab treatment reduced free serum IgE prior to the second omalizumab injection by 73%, after 16 weeks by 81% to 58 ± 12 ng/ml (p < 0.001 vs. baseline). 17 patients responded to anti-IgE therapy as judged by physician-rated global evaluation of treatment effectiveness. There was neither a relation between free serum IgE concentrations and treatment response nor a significant or clinically relevant correlation between free IgE levels and changes in lung function, exhaled NO, asthma control, and quality of life. Serum concentrations of omalizumab were detected in all patients and reached a stable phase within 8 weeks.

CONCLUSIONS

Monitoring free IgE and omalizumab serum concentrations in patients treated with omalizumab does not predict clinical response nor does it add to the decision to continue or stop treatment. However, routine measurements of free IgE may be clinically relevant to demonstrate an adequate reduction in free IgE in patients not responding to omalizumab therapy.

A review of current bronchoscopic interventions for obstructive airway diseases

Obstructive diseases of the airway are a diverse group, although they share in common airway narrowing as a sequel to inflammation, which leads to increased work of breathing. Optimal treatment strategies for this heterogeneous group of asthma, chronic bronchitis and emphysema should be multidimensional and embrace pharmacological and nonpharmacological means as well as surgery in a highly select group of patients with emphysema. We review the current status of the bronchoscopic interventions that have been in development for the past decade with the objectives of providing better symptom control in asthma and palliation in individuals with emphysema who are otherwise poor candidates for lung volume reduction surgery.

International consensus on (ICON) pediatric asthma

Asthma is the most common chronic lower respiratory disease in childhood throughout the world. Several guidelines and/or consensus documents are available to support medical decisions on pediatric asthma. Although there is no doubt that the use of common systematic approaches for management can considerably improve outcomes, dissemination and implementation of these are still major challenges. Consequently, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), recently formed by the EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus on (ICON) Pediatric Asthma. The purpose of this document is to highlight the key messages that are common to many of the existing guidelines, while critically reviewing and commenting on any differences, thus providing a concise reference. The principles of pediatric asthma management are generally accepted. Overall, the treatment goal is disease control. To achieve this, patients and their parents should be educated to optimally manage the disease, in collaboration with healthcare professionals. Identification and avoidance of triggers is also of significant importance. Assessment and monitoring should be performed regularly to re-evaluate and fine-tune treatment. Pharmacotherapy is the cornerstone of treatment. The optimal use of medication can, in most cases, help patients control symptoms and reduce the risk for future morbidity. The management of exacerbations is a major consideration, independent of chronic treatment. There is a trend toward considering phenotype-specific treatment choices; however, this goal has not yet been achieved.

Response of peripheral blood Th17 cells to inhaled Dermatophagoides pteronyssinus in patients with allergic rhinitis and asthma

BACKGROUND

Recent studies have shown the importance of Th17 cells in the development of allergic airway diseases. We examined Dermatophagoides pteronyssinus-induced changes in peripheral blood Th17 cells to establish the importance of these cells in late-phase allergic inflammation in patients with allergic rhinitis (AR) and allergic asthma (AA).

METHODS

Eighteen patients with mild-to-moderate/severe persistent AR, 14 patients with intermittent- or mild-to-moderate persistent AA, and 15 healthy subjects (HS) were examined. All patients had positive skin test to D. pteronyssinus. Study subjects underwent bronchial challenge with D. pteronyssinus. The peripheral blood Th1, Th2, and Th17 cells were determined by flow cytometry 24 h before and 7 and 24 h after challenge. The serum IL-17 levels were determined by ELISA.

RESULTS

The percentage of Th17 cells and IL-17 levels was significantly higher in patients with AR and AA compared with HS before and after challenge. Twenty-four hours after challenge, the percentage of Th17 cells increased significantly in patients with AA compared with baseline values. The IL-17 levels rose markedly in patients with AR and AA after challenge. Moreover, 24 h after challenge, the percentage of Th17 cells and IL-17 levels were significantly higher in patients with AA than those with AR.

CONCLUSIONS

Percentages of peripheral blood Th17 cells and serum IL-17 levels were found to be higher in patients with AR and AA. An increase in the percentage of Th17 cells following challenge shows that Th17 cells may have an important role in the development of late-phase allergen-induced inflammation.

The potential use of tyrosine kinase inhibitors in severe asthma

PURPOSE OF REVIEW

Severe asthma comprises heterogeneous phenotypes that share in common a poor response to traditional therapies. Recent and ongoing work with tyrosine kinase inhibitors suggests a potential beneficial role in treatment of severe asthma.

RECENT FINDINGS

Various receptor and nonreceptor tyrosine kinase pathways contribute to aspects of airway inflammation, airway hyperresponsiveness, and remodeling of asthma. Selective and nonselective tyrosine kinase inhibitors may be useful to block pathways that are pathologically overactive or overexpressed in severe asthma. Recent in-vivo studies have demonstrated the utility of inhibitors against specific tyrosine kinases (epidermal growth factor receptor, c-kit/platelet derived growth factor receptor, vascular endothelial growth factor receptor, spleen tyrosine kinase, and janus kinase) in altering key aspects of severe asthma.

SUMMARY

Asthma and even severe asthma does not consist of a single phenotype. Targeting key inflammatory and remodeling pathways engaged across subphenotypes with tyrosine kinase inhibitors appears to hold promise.

Rationale for the use of immunomodulatory therapies in the Global Initiative for Asthma (GINA) step V asthma other than oral glucocorticosteroids

Asthma is a major problem worldwide, which is estimated to affect 300 million individuals. The global prevalence ranges from 1% to 18% of the population. The incidence, morbidity and mortality of the condition have increased over the last 50 years despite the development of new anti-asthmatic drugs. Fewer than 1% of the asthmatic population are steroid-dependent, but these patients consume most of the resources and time at asthma units. The consensus documents published by professional societies all support a stepwise therapeutic approach for asthma. However, patients who require frequent or continuous oral corticosteroid administration have received little attention. Due to the severe side-effects of oral corticosteroids when administered over long periods or at high doses, many drugs have been assessed in the search for a possible corticosteroid-sparing agent. Recently, the update of the Global Initiative for Asthma (GINA) introduced a new drug--omalizumab--as an alternative to oral corticosteroids in patients included in step V. Other alternatives include immunosuppressive drugs, among which methotrexate has been found to offer the best benefit/risk ratio. This paper will review, comment and criticize the evidence of the effectiveness of immunomodulatory drugs, as an alternative to oral glucocorticosteroid treatment in GINA step V asthma patients. The experience of the authors combined with the information of the literature will lead to the conclusion that methotrexate and omalizumab are the only advisable drugs and will clarify when and how these drugs should be used.

Evidence of association between interferon regulatory factor 5 gene polymorphisms and asthma

Asthma is a heterogeneous disorder hallmarked by chronic inflammation in the respiratory system. Exacerbations of asthma are correlated with respiratory infections. Considering the implication of interferon regulatory factor 5 (IRF5) in innate and adaptive immunity, we investigated the preferential transmission patterns of ten IRF5 gene polymorphisms in two asthmatic family cohorts. A common IRF5 haplotype was found to be associated with asthma and the severity of asthmatic symptoms. Stratified analysis of subgroups of asthmatic individuals revealed that the associations were more pronounced in nonatopic asthmatic individuals. In addition, the risk alleles of IRF5 polymorphisms for asthma were almost completely opposite to those for autoimmune disorders. Our study provides the first evidence of association between IRF5 and asthma, and sheds light on the related but potentially distinct roles of IRF5 alleles in the pathogenesis of asthma and autoimmune disorders.

Epigenetics in asthma and other inflammatory lung diseases

Asthma is a chronic inflammatory disease of the airways. The causes of asthma and other inflammatory lung diseases are thought to be both environmental and heritable. Genetic studies do not adequately explain the heritability and susceptabilty to the disease, and recent evidence suggests that epigentic changes may underlie these processes. Epigenetics are heritable noncoding changes to DNA and can be influenced by environmental factors such as smoking and traffic pollution, which can cause genome-wide and gene-specific changes in DNA methylation. In addition, alterations in histone acetyltransferase/deacetylase activities can be observed in the cells of patients with lung diseases such as severe asthma and chronic obstructive pulmonary disease, and are often linked to smoking. Drugs such as glucocorticoids, which are used to control inflammation, are dependent on histone deacetylase activity, which may be important in patients with severe asthma and chronic obstructive pulmonary disease who do not respond well to glucocorticoid therapy. Future work targeting specific histone acetyltransferases/deacetylases or (de)methylases may prove to be effective future anti-inflammatory treatments for patients with treatment-unresponsive asthma.

[Management of acute asthma]

INTRODUCTION

All patients with asthma are at risk of exacerbations. Mortality is often associated with failure to identify patients at risk and/or to appreciate the severity of acute episode, resulting in inadequate initial treatment, delay in referring to emergency care and inappropriate hospitalization rates, including delayed transfer to intensive care units. This review focuses on the management of acute severe and near fatal asthma.

STATE OF ART

Lung mechanics and cardiopulmonary interactions associated with airflow obstruction explain the physical presentation and severity criteria for exacerbations. The past and recent medical history, the initial evaluation of severity and the assessment of response to treatment direct the in-hospital management: emergency department visit, transfer to ward or intensive care unit. In any cases, the goals of therapy are summarized as oxygenation, repetitive inhalations of bronchodilators and early administration of systemic corticosteroids. Mechanical ventilation is required in a few patients with near fatal attacks resulting in asphyxia or progressive exhaustion despite maximal therapy. Controlled hypoventilation with permissive hypercapnia is the best strategy to avoid barotrauma. The role of adjunctive therapies, mainly halogenated agents and heliox, is discussed.

PERSPECTIVES AND CONCLUSION

During the last decade, asthma related mortality has decreased in France (<1000/year). The majority of deaths occur at home or during transport to the hospital but some deaths occur suddenly. Most deaths could be preventable if one adopts the approach that every exacerbation is potentially fatal. This practice should be more vigorously included in patient and general practitioner educational programs.

Increased neutrophilia in nasal polyps reduces the response to oral corticosteroid therapy

BACKGROUND

Nasal polyps (NPs) are characterized by eosinophilic inflammation, which is generally considered sensitive to corticosteroid treatment.

OBJECTIVES

We evaluated levels of neutrophilia in NPs and investigated whether increased neutrophilia in polyp tissue affected the response to corticosteroid treatment.

METHODS

We studied 3 independent cross-sectional groups of patients with NPs. Levels of infiltration by different types of inflammatory cells were determined by using immunohistochemical analyses and compared with those seen in control nasal tissues from subjects without NPs. Levels of inflammatory mediators were measured by using real-time PCR, ELISA, and FlowCytomix analyses. Patients with NPs received oral corticosteroid therapy (30 mg of prednisone once daily for 7 days); clinical parameters of efficacy were associated with NP phenotypes.

RESULTS

Among patients with NPs, 76.5% had an eosinophilic phenotype, 46.0% had a neutrophilic phenotype, and 35.8% had a mixed phenotype (indicated by double staining). Overall, patients' symptoms improved after corticosteroid treatment; numbers of eosinophils and levels of their mediators (IL-4 and IL-5), but not numbers of neutrophils or levels of their mediators (IL-8 and interferon-inducible protein 10), were reduced (P< .05). After corticosteroid treatment, patients with the nonneutrophilic phenotype (neutrophil negative) had significantly greater reductions in bilateral polyp size scores, nasal congestion scores, total nasal symptom scores, and nasal resistance than patients with the neutrophilic phenotype (neutrophil positive, P< .05).

CONCLUSIONS

There are different phenotypes of NPs based on the type of immune cell infiltrate and cytokines produced (eosinophilic or neutrophilic). Patients with the neutrophilic phenotype have less response to treatment with corticosteroids based on symptom scores.

Potential association of DDR1 genetic variant with FEV1 decline by aspirin provocation in asthmatics

BACKGROUND

The discoidin domain receptor tyrosine kinase 1 (DDR1) is positioned within the major histocompatibility complex (MHC) region which plays an important role in the immune system. In addition, DDR1 has been elucidated to be downregulated during the epithelial-mesenchymal transition of bronchial epithelium.

OBJECTIVE

To investigate the potential genetic associations between DDR1 and aspirin-exacerbated respiratory disease (AERD), this study conducted association studies of DDR1 single nucleotide polymorphisms (SNPs) with AERD and the obstructive symptom of forced expiratory volume in 1 s (FEV(1)) decline after aspirin provocation.

METHODS

Nine common SNPs were genotyped in 93 AERD patients and 96 aspirin-tolerant asthma (ATA) controls. The genotype distributions of all loci were in Hardy-Weinberg equilibrium (HWE; p > .05). Results. In the results of logistic analyses using age, sex, smoking status, and atopy as covariates, DDR1 rs1264320 in the intronic region showed a potent association signal with FEV(1) decline by aspirin provocation in asthmatics of this study even after corrections for multiple testing (p = .003 and corrected p = .01). However, the variants of DDR1 were not significantly associated with the AERD development (corrected p > .05). On further comparison of FEV(1) decline by aspirin provocation between AERD and ATA, the variant rs1264320 was found to be associated with the FEV(1) decline of ATA rather than AERD.

CONCLUSION

Despite the need for further functional evaluations and replications, we conclude that DDR1 polymorphisms are not likely to contribute to predispositions of AERD, but may be potentially associated with FEV(1) decline by aspirin provocation in asthmatics.

Treatment with a sphingosine-1-phosphate analog inhibits airway remodeling following repeated allergen exposure

Sphingosine-1-phosphate (S1P) is an immunomodulatory lipid mediator that plays an important role in lymphocyte trafficking. Elevated levels of S1P are found in bronchoalveolar lavage (BAL) fluid of patients with asthma; however, its role in disease is not known. FTY720, a synthetic analog of S1P, has been shown to abrogate allergic inflammation and airway hyperresponsiveness following acute allergen challenge. However, its effects on asthmatic airway remodeling induced by repeated allergen exposure are unknown. Ovalbumin (OVA)-sensitized rats were challenged on days 14, 19, and 24 after sensitization. FTY720 or vehicle (PBS) therapy was administered 1 h prior to each challenge. BAL fluid and quantitative histological analysis were performed 48 h after the last challenge. FTY720 inhibited OVA-induced features of airway remodeling including increased airway smooth muscle mass and bronchial neovascularization, without affecting lymphocyte numbers in secondary lymphoid organs. Furthermore, CD3+ cells adjacent to airway smooth muscle bundles were increased in OVA-challenged rats but the increase was inhibited by FTY720. There was an expansion of bronchus-associated lymphoid tissue following FTY720 treatment of OVA-challenged animals. Real-time quantitative PCR revealed that Th2-associated transcription factors were inhibited following FTY720 therapy. Airway remodeling is a cardinal feature of severe asthma. These results demonstrate that allergen-driven airway remodeling can be inhibited by FTY720, offering potential new therapies for the treatment of severe asthma.

Monoclonal antibodies for chronic refractory asthma and pipeline developments

Patients with severe asthma suffer persistent symptoms and/or frequent exacerbations despite high-intensity treatment. Their severe unrelenting symptoms have a huge impact on healthcare resources owing to frequent hospital admissions and requirement for intensive treatments. Consequently, there is an undeniable need for more-effective and safer medications. Expanding knowledge of innate and adaptive immune responses is leading to the development of novel therapies for severe asthma. Herein, we review efficacy and safety data from human clinical trials of monoclonal antibodies that are approved or under investigation for use in asthma. Future drug candidates directed at key targets and the specific role of monoclonal antibodies in distinctively targeted sub-populations of severe asthmatics will be also discussed.