Lung function and sputum characteristics of patients with severe asthma during an induced exacerbation by double-blind steroid withdrawal

Impact of Ongoing Treatment With Inhaled Corticosteroids During Specific Inhalation Challenges for Diagnosing Occupational Asthma

BACKGROUND

Specific inhalation challenge (SIC) tests are still the reference test for diagnosing sensitizer-induced occupational asthma (SIOA). The European Respiratory Society recommends the cessation of inhaled corticosteroids (ICS) 72 hours before SIC.

OBJECTIVE

To assess the effect of an ongoing ICS treatment during SIC on the maximum fall in forced expiratory volume in 1 second (FEV1), the change in methacholine provocative concentration of methacholine inducing a 20% fall in FEV1 (PC20), and sputum eosinophil counts after exposure to the suspected agent.

METHODS

We performed a retrospective analysis using a database of cases referred to our center for suspected SIOA from 1999 to 2022. The results of the SIC were compared between subjects treated with ICS during SIC and steroid-naïve subjects.

RESULTS

Six hundred and seventy-one individuals underwent SIC in the laboratory. Three hundred and eighteen were treated with ICS, whereas 353 were steroid naïve. The proportion of subjects with a positive SIC was greater among ICS-treated subjects (39. 6%) compared with steroid-naïve subjects (27.5%, P < .001). A treatment with ICS did not influence the outcome of the SIC. There was no difference in the change in PC20 or the percentage of sputum eosinophils after SIC between steroid-treated and steroid-naïve subjects.

CONCLUSIONS

An ongoing ICS treatment during an SIC did not affect the occurrence of an asthmatic reaction, the change in airway responsiveness, or eosinophilic inflammation after exposure to the suspected agent in subjects who have been treated with ICS for a long period of time.

Single-Cell Hypertrophy Promotes Contractile Function of Cultured Human Airway Smooth Muscle Cells via Piezo1 and YAP Auto-Regulation

Severe asthma is characterized by increased cell volume (hypertrophy) and enhanced contractile function (hyperresponsiveness) of the airway smooth muscle cells (ASMCs). The causative relationship and underlying regulatory mechanisms between them, however, have remained unclear. Here, we manipulated the single-cell volume of in vitro cultured human ASMCs to increase from 2.7 to 5.2 and 8.2 × 103 μm3 as a simulated ASMC hypertrophy by culturing the cells on micropatterned rectangular substrates with a width of 25 μm and length from 50 to 100 and 200 μm, respectively. We found that as the cell volume increased, ASMCs exhibited a pro-contractile function with increased mRNA expression of contractile proteins, increased cell stiffness and traction force, and enhanced response to contractile stimulation. We also uncovered a concomitant increase in membrane tension and Piezo1 mRNA expression with increasing cell volume. Perhaps more importantly, we found that the enhanced contractile function due to cell volume increase was largely attenuated when membrane tension and Piezo1 mRNA expression were downregulated, and an auto-regulatory loop between Piezo1 and YAP mRNA expression was also involved in perpetuating the contractile function. These findings, thus, provide convincing evidence of a direct link between hypertrophy and enhanced contractile function of ASMCs that was mediated via Piezo1 mRNA expression, which may be specifically targeted as a novel therapeutic strategy to treat pulmonary diseases associated with ASMC hypertrophy such as severe asthma.

Airway hyperresponsiveness in asthma: The role of the epithelium

Airway hyperresponsiveness (AHR) is a key clinical feature of asthma. The presence of AHR in people with asthma provides the substrate for bronchoconstriction in response to numerous diverse stimuli, contributing to airflow limitation and symptoms including breathlessness, wheeze, and chest tightness. Dysfunctional airway smooth muscle significantly contributes to AHR and is displayed as increased sensitivity to direct pharmacologic bronchoconstrictor stimuli, such as inhaled histamine and methacholine (direct AHR), or to endogenous mediators released by activated airway cells such as mast cells (indirect AHR). Research in in vivo human models has shown that the disrupted airway epithelium plays an important role in driving inflammation that mediates indirect AHR in asthma through the release of cytokines such as thymic stromal lymphopoietin and IL-33. These cytokines upregulate type 2 cytokines promoting airway eosinophilia and induce the release of bronchoconstrictor mediators from mast cells such as histamine, prostaglandin D2, and cysteinyl leukotrienes. While bronchoconstriction is largely due to airway smooth muscle contraction, airway structural changes known as remodeling, likely mediated in part by epithelial-derived mediators, also lead to airflow obstruction and may enhance AHR. In this review, we outline the current knowledge of the role of the airway epithelium in AHR in asthma and its implications on the wider disease. Increased understanding of airway epithelial biology may contribute to better treatment options, particularly in precision medicine.

Childhood asthma treatment based on indirect hyperresponsiveness test: Randomized controlled trial

PURPOSE

The purpose of this study was to assess the usefulness of indirect airway hyperresponsiveness (AHR) test using hypertonic saline in determining the dose of inhaled corticosteroids (ICS) to maintain asthma control in children.

METHODS

A group of 104 patients (7-15 years) with mild-moderate atopic asthma were monitored for their asthma control and treatment for 1 year. Patients were randomly assigned to a symptom-only monitored group and a group with therapy changes based on the symptoms and severity of AHR. Spirometry, exhaled nitric oxide, and blood eosinophils (BEos) were assessed on enrollment and every 3 months thereafter.

RESULTS

During the study period, the number of mild exacerbations was lower in the AHR group (44 vs. 85; the absolute rate per patient 0.83 vs. 1.67; relative rate 0.49, 95% confidence interval: 0.346-0.717 (p < 0.001)]. Mean changes from baseline in clinical (except asthma control test), inflammatory, and lung function parameters were similar between groups. Baseline BEos correlated with AHR and was a risk factor for recurrent exacerbation in all patients. There was no significant difference in the final ICS dose between AHR and symptoms group: 287 (SD 255) vs. 243 (158) p = 0.092.

CONCLUSIONS

Adding an indirect AHR test to clinical monitoring of childhood asthma reduced the number of mild exacerbations, with similar current clinical control and final ICS dose as in the symptom-monitored group. The hypertonic saline test appears to be a simple, cheap, and safe tool for monitoring the treatment of mild-to-moderate asthma in children.

STOP: an open label crossover trial to study ICS withdrawal in patients with a combination of obesity and low-inflammatory asthma and evaluate its effect on asthma control and quality of life

Background

Asthma patients with obesity often have a high disease burden, despite the use of high-dose inhaled corticosteroids (ICS). In contrast to asthmatics with normal weight, the efficacy of ICS in patients with obesity and asthma is often relatively low. Meanwhile, patients do suffer from side effects, such as weight gain, development of diabetes, cataract, or high blood pressure. The relatively poor response to ICS might be explained by the low prevalence of type 2 inflammatory patterns (T2-low) in patients with asthma and obesity. T2-low inflammation is characterized by low eosinophilic count, low Fractional exhaled NO (FeNO), no clinically allergy-driven asthma, and no need for maintenance oral corticosteroids (OCS). We aim to study whether ICS can be safely withdrawn in patients with T2-low asthma and obesity while maintaining an equal level of asthma control. Secondary outcomes focus on the prevalence of ‘false-negative’ T2-low phenotypes (i.e. T2-hidden) and the effect of ICS withdrawal on parameters of the metabolic syndrome. This study will lead to a better understanding of this poorly understood subgroup and might find new treatable traits.

Methods

The STOP trial is an investigator-initiated, multicenter, non-inferiority, open-label, crossover study aiming to assess whether ICS can be safely withdrawn in adults aged 17–75 years with T2-low asthma and obesity (body mass index (BMI) ≥ 30 kg/m2). Patients will be randomly divided into two arms (both n = 60). One arm will start with fixed-dose ICS (control group) and one arm will taper and subsequently stop ICS (intervention group). Patients in the intervention group will remain ICS naïve for ten weeks. After a washout of 4 weeks, patients will crossover to the other study arm. The crossover study takes 36 weeks to complete. Patients will be asked to participate in the extension study, to investigate the long-term metabolic benefits of ICS withdrawal.

Discussion

This study yields valuable data on ICS tapering in patients with T2-low asthma and obesity. It informs future guidelines and committees on corticosteroid-sparing algorithms in these patients.

Trial registration Netherlands Trial Register, NL8759, registered 2020–07-06, https://www.trialregister.nl/trial/8759.

Protocol version and date: version 2.1, 20 November 2020.

Noninvasive and minimally invasive techniques for the diagnosis and management of allergic diseases

Allergic diseases of the (upper and lower) airways, the skin and the gastrointestinal tract, are on the rise, resulting in impaired quality of life, decreased productivity, and increased healthcare costs. As allergic diseases are mostly tissue-specific, local sampling methods for respective biomarkers offer the potential for increased sensitivity and specificity. Additionally, local sampling using noninvasive or minimally invasive methods can be cost-effective and well tolerated, which may even be suitable for primary or home care sampling. Non- or minimally invasive local sampling and diagnostics may enable a more thorough endotyping, may help to avoid under- or overdiagnosis, and may provide the possibility to approach precision prevention, due to early diagnosis of these local diseases even before they get systemically manifested and detectable. At the same time, dried blood samples may help to facilitate minimal-invasive primary or home care sampling for classical systemic diagnostic approaches. This EAACI position paper contains a thorough review of the various technologies in allergy diagnosis available on the market, which analytes or biomarkers are employed, and which samples or matrices can be used. Based on this assessment, EAACI position is to drive these developments to efficiently identify allergy and possibly later also viral epidemics and take advantage of comprehensive knowledge to initiate preventions and treatments.

Towards a personalised treatment approach for asthma attacks

Asthma attacks (exacerbations) are common, accounting for over 90 000 UK hospital admissions per annum. They kill nearly 1500 people per year in the UK, have significant associated direct and indirect costs and lead to accelerated and permanent loss of lung function. The recognition of asthma as a heterogeneous condition with multiple phenotypes has revolutionised the approach to the long-term management of the condition, with greater emphasis on personalised treatment and the introduction of the treatable traits concept. In contrast asthma attacks are poorly defined and understood and our treatment approach consists of bronchodilators and systemic corticosteroids. This review aims to explore the current limitations in the description, assessment and management of asthma attacks. We will outline the risk factors for attacks, strategies to modify this risk and describe the recognised characteristics of attacks as a first step towards the development of an approach for phenotyping and personalising the treatment of these critically important events. By doing this, we hope to gradually improve asthma attack treatment and reduce the adverse effects associated with recurrent courses of corticosteroids.

Corticosteroid Withdrawal-Induced Loss of Control in Mild to Moderate Asthma Is Independent of Classic Granulocyte Activation

BACKGROUND

Loss of asthma control and asthma exacerbations are associated with increased sputum eosinophil counts. However, whether eosinophils, or the also present neutrophils, actively contribute to the accompanying inflammation has not been extensively investigated.

METHODS

Twenty-three patients with mild to moderate asthma were included in a standardized prospective inhaled corticosteroid (ICS) withdrawal study; 22 of the patients experienced loss of asthma control. The study assessed various immune, inflammatory, and oxidative stress parameters, as well as markers of eosinophil and neutrophil activity, in exhaled breath condensate, plasma, and sputum collected at three phases (baseline, during loss of control, and following recovery).

RESULTS

Loss of asthma control was characterized by increased sputum eosinophils, whereas no differences were detected between the three phases for most inflammatory and oxidative stress responses. There were also no differences detected for markers of activated eosinophils (eosinophil cationic protein and bromotyrosine) and neutrophils (myeloperoxidase and chlorotyrosine). However, free eosinophilic granules and citrullinated histone H₃, suggestive of eosinophil cytolysis and potentially eosinophil extracellular trap formation, were enhanced. Baseline blood eosinophils and changes in asymmetric dimethylarginine (an inhibitor of nitric oxide synthase) in plasma were found to correlate with the decrease in FEV₁ percent predicted upon ICS withdrawal (both, r_s = 0.46; P = .03).

CONCLUSIONS

The clinical effect in mild to moderate asthma upon interruption of ICS therapy is not related to the classic inflammatory activation of eosinophils and neutrophils. It may, however, reflect another pathway underlying the onset of loss of disease control and asthma exacerbations.

TRIAL REGISTRY

The Netherlands Trial Register; No.: NTR3316; URL: trialregister.nl/trial/3172.

Asthma Endotyping and Biomarkers in Childhood Asthma

Childhood asthma represents a heterogeneous challenging disease, in particular in its severe forms. The identification of different asthma phenotypes has stimulated research in underlying molecular mechanisms, such as the endotypes, and paved the way to the search for related specific biomarkers, which may guide diagnosis, management, and predict response to treatment. A limited number of biomarkers are currently available in clinical practice in the pediatric population, mostly reflecting type 2-high airway inflammation. The identification of biomarkers of childhood asthma is an active area of research that holds a potential great clinical utility and may represent a step forward toward tailored management and therapy: the so-called Precision Medicine. The aim of the present review is to provide an updated overview of asthma endotyping, mostly focusing on novel noninvasive biomarkers in childhood asthma.

Effects of treatment changes on asthma phenotype prevalence and airway neutrophil function

Background

Asthma inflammatory phenotypes are often defined by relative cell counts of airway eosinophils/neutrophils. However, the importance of neutrophilia remains unclear, as does the effect of ICS treatment on asthma phenotypes and airway neutrophil function. The purpose of this study was to assess asthma phenotype prevalence/characteristics in a community setting, and, in a nested preliminary study, determine how treatment changes affect phenotype stability and inflammation, with particular focus on airway neutrophils.

Methods

Fifty adult asthmatics and 39 non-asthmatics were assessed using questionnaires, skin prick tests, spirometry, exhaled nitric oxide (FENO) measurement, and sputum induction. Twenty-one asthmatics underwent further assessment following treatment optimisation (n = 11) or sub-optimisation (n = 10).

Results

Forty percent (20/50) had eosinophilic asthma (EA) and 8% had neutrophilic asthma. EA was associated with increased FENO, bronchodilator reversibility (BDR) and reduced lung function (p < 0.05). Following optimisation/sub-optimisation, the EA/NEA (non-eosinophilic asthma) phenotype changed in 11/21 (52%) asthmatics. In particular, fewer subjects had EA post treatment optimisation, but this was not statistically significant. However, a significant (p < 0.05) reduction in FENO, ACQ7 score, and BDR was observed after treatment optimisation, as well as an increase in FEV₁-% predicted (p < 0.05). It was also associated with reduced eosinophils (p < 0.05) and enhanced neutrophil phagocytosis (p < 0.05) in EA only, and enhanced neutrophil oxidative burst in both EA and NEA (p < 0.05).

Conclusions

In this community based population, non-eosinophilic asthma was common, less severe than EA, and at baseline most asthmatics showed no evidence of inflammation. In the nested change in treatment study, treatment optimisation was associated with reduced sputum eosinophils, improved symptoms and lung function, and enhanced neutrophil function, but a significant reduction in EA could not be demonstrated.

Trial registration

The nested change in treatment component of this study is registered at the Australia and New Zealand Clinical Trial Registry (www.ANZCTR.org.au) ACTRN12617001356358. Registration date 27/09/2017. Retrospectively registered.

Electronic supplementary material

The online version of this article (10.1186/s12890-017-0511-6) contains supplementary material, which is available to authorized users.

Exhaled breath profiles in the monitoring of loss of control and clinical recovery in asthma

BACKGROUND

Asthma is a chronic inflammatory airway disease, associated with episodes of exacerbations. Therapy with inhaled corticosteroids (ICS) targets airway inflammation, which aims to maintain and restore asthma control. Clinical features are only modestly associated with airways inflammation. Therefore, we hypothesized that exhaled volatile metabolites identify longitudinal changes between clinically stable episodes and loss of asthma control.

OBJECTIVES

To determine whether exhaled volatile organic compounds (VOCs) as measured by gas-chromatography/mass-spectrometry (GC/MS) and electronic nose (eNose) technology discriminate between clinically stable and unstable episodes of asthma.

METHODS

Twenty-three patients with (partly) controlled mild to moderate persistent asthma using ICS were included in this prospective steroid withdrawal study. Exhaled metabolites were measured at baseline, during loss of control and after recovery. Standardized sampling of exhaled air was performed, after which samples were analysed by GC/MS and eNose. Univariate analysis of covariance (ANCOVA), followed by multivariate principal component analysis (PCA) was used to reduce data dimensionality. Next paired t tests were utilized to analyse within-subject breath profile differences at the different time-points. Finally, associations between exhaled metabolites and sputum inflammation markers were examined.

RESULTS

Breath profiles by eNose showed 95% (21/22) correct classification for baseline vs loss of control and 86% (19/22) for loss of control vs recovery. Breath profiles using GC/MS showed accuracies of 68% (14/22) and 77% (17/22) for baseline vs loss of control and loss of control vs recovery, respectively. Significant associations between exhaled metabolites captured by GC/MS and sputum eosinophils were found (Pearson r≥.46, P<.01).

CONCLUSIONS & CLINICAL RELEVANCE

Loss of asthma control can be discriminated from clinically stable episodes by longitudinal monitoring of exhaled metabolites measured by GC/MS and particularly eNose. Part of the uncovered biomarkers was associated with sputum eosinophils. These findings provide proof of principle for monitoring and identification of loss of asthma control by breathomics.

Current and future biomarkers in allergic asthma

Diagnosis early in life, sensitization, asthma endotypes, monitoring of disease and treatment progression are key motivations for the exploration of biomarkers for allergic rhinitis and allergic asthma. The number of genes related to allergic rhinitis and allergic asthma increases steadily; however, prognostic genes have not yet entered clinical application. We hypothesize that the combination of multiple genes may generate biomarkers with prognostic potential. The current review attempts to group more than 161 different potential biomarkers involved in respiratory inflammation to pave the way for future classifiers. The potential biomarkers are categorized into either epithelial or infiltrate-derived or mixed origin, epithelial biomarkers. Furthermore, surface markers were grouped into cell-type-specific categories. The current literature provides multiple biomarkers for potential asthma endotypes that are related to T-cell phenotypes such as Th1, Th2, Th9, Th17, Th22 and Tregs and their lead cytokines. Eosinophilic and neutrophilic asthma endotypes are also classified by epithelium-derived CCL-26 and osteopontin, respectively. There are currently about 20 epithelium-derived biomarkers exclusively derived from epithelium, which are likely to innovate biomarker panels as they are easy to sample. This article systematically reviews and categorizes genes and collects current evidence that may promote these biomarkers to become part of allergic rhinitis or allergic asthma classifiers with high prognostic value.

Therapeutic novelties of inhaled corticosteroids and bronchodilators in asthma

Orally inhaled agents are a key therapeutic class for treatment of asthma. Inhaled corticosteroids (ICS) are the most effective anti-inflammatory treatment for asthma thus representing the first-line therapy and bronchodilators complement the effects of ICSs. A significant body of evidence indicates that addition of a β2-agonist to ICS therapy is more effective than increasing the dose of ICS monotherapy. In this paper, pharmacological features of available ICSs and bronchodilators will be reviewed with a focus on fluticasone propionate/formoterol fumarate combination which represents the one of the most powerful ICS acting together with the most rapid active LABA.

Association of interleukin 6 single nucleotide polymorphisms with allergic rhinitis

OBJECTIVES

Allergic rhinitis (AR) is a polygenic inflammatory disorder of the nasal mucosa with an increasing prevalence worldwide. As interleukin 6 (IL-6) seems to be involved in development of allergic disorders, such as allergic rhinitis, this study was performed to evaluate the association of two promotor variants of IL-6 gene in the AR.

METHODS

Ninety eight patients with AR were enrolled in this study. Genotyping was done for two polymorphisms in a promoter region of IL-6 gene (G/C at -174, rs1800795 and G/A at -597, rs1800797), using a PCR sequence-specific-primers method.

RESULTS

Patients homozygous for the G allele of rs1800795 in IL-6 had a 3.35-fold risk of having AR than those with the C allele. AA genotype in rs1800797 of IL-6 was associated with the increased risk of developing AR. G/G haplotype for IL-6 (rs1800795, rs1800797) was significantly higher in the patient group. In some subgroups of patients, there were significant relationships between IgE levels, eosinophil count, eosinophil percentage, nature of sensitivity and persistency of disease and these two variants.

CONCLUSION

We found that two promotor variants in IL-6, especially rs1800795, were predisposing factors for AR with a negative heterosis pattern. These SNPs could also affect the clinical parameters, the nature of sensitivity and persistency of the disease in some subgroups of the patients.

Multi-allergen challenge stimulates steriod-resistant airway inflammation via NF-κB-mediated IL-8 expression

Neutrophilic airway inflammation associated with multiple allergens has been related to steroid-resistant asthma. However, most animal models use only one allergen, which cannot simulate asthma closely as seen in patients. To determine the mechanism of inflammatory process involved in this severe condition, BALB/c mice were repetitively challenged with the pooled extract of dust mite, ragweed, and Aspergillus species (DRA). We found that DRA increased interleukin (IL)-10 and TGF-β levels and neutrophil recruitment in bronchial alveolar lavage fluid. We also found that although dexamethasone suppressed the release of these two cytokines, mast cells recruitment, and mucus hypersecretion, it actually increased neutrophil infiltration and the level of keratinocyte-derived chemokine (mKC), a functional homolog of human IL-8. Treatment of human lung alveolar A549 cells with Der p1, an extract of house dust mite Dermatophagoides pteronyssinus, increased the expression of IL-8 and activity of NF-κB. The elevated IL-8 level was suppressed by BAY11-7082, a selective NF-κB inhibitor, but not by dexamethasone. These results suggest that increased IL-8 (mKC) levels may be involved in steroid-resistant neutrophilic airway inflammation through an NF-κB-dependent pathway.

The misuse of asthma drugs

There are three major problems with asthma care in the USA and misuse of asthma drug therapy contributes to each. Asthma patients suffer from symptoms regularly partly because healthcare providers do not understand the Expert Panel Report III (EPR3) recommendations on assessing asthma symptoms to determine drug treatment and, consequently, undertreat the disease. Asthma patients experience exacerbations often in part because the EPR3 provides limited guidance on using exacerbation risk to guide asthma treatment, again leading to undertreatment. The EPR3 recommends inhaled corticosteroids as the preferred therapy for mild persistent asthma but American healthcare providers disregard this recommendation based on different perceptions about the risks and benefits of inhaled corticosteroids and choose drug treatments with higher healthcare costs.

Inhibitory effect of dexamethasone on expression of cysteine-rich 61 protein in airway epithelial cells of allergic mouse models

In order to study whether cysteine-rich 61 protein (cyr61) is involved in the pathogenesis of asthma and its relation to airway inflammation, the effect of dexamethasone (Dxm) on the expression of cyr61 in the lung tissues of asthmatic mice was investigated. Forty BALB/c mice were divided into asthma group (n=15), control group (n=10) and Dxm group (n=15). The asthma group was sensitized and challenged by ovalbumin (OVA). The mice in Dxm group were intraperitoneally administered with Dxm after OVA challenge. The expression of cyr61 in the lung tissues was detected by using immunohistochemistry, and that of eotaxin protein in the bronchoalveolar lavage fluid (BALF) by using enzyme-linked immunosorbent assay (ELISA). The number of inflammatory cells in BALF was also analyzed. The results showed that the cyr61 expression was highest in asthma group (P<0.05), followed by Dxm group (P<0.05) and control group. The cyr61 had a positive correlation with the total nucleated cells (r=0.867, P<0.05), especially eosinophils (r=0.856, P<0.05), and eotaxin level (r=0.983, P<0.05) in the BALF. Our findings suggested that cyr61 is expressed in airway epithelial cells and has a positive correlation with eotaxin and number of airway infiltrating eosinophils.

Interleukin-33 drives activation of alveolar macrophages and airway inflammation in a mouse model of acute exacerbation of chronic asthma

We investigated the role of interleukin-33 (IL-33) in airway inflammation in an experimental model of an acute exacerbation of chronic asthma, which reproduces many of the features of the human disease. Systemically sensitized female BALB/c mice were challenged with a low mass concentration of aerosolized ovalbumin for 4 weeks to induce chronic asthmatic inflammation and then received a single moderate-level challenge to trigger acute airway inflammation simulating an asthmatic exacerbation. The inflammatory response and expression of cytokines and activation markers by alveolar macrophages (AM) were assessed, as was the effect of pretreatment with a neutralizing antibody to IL-33. Compared to chronically challenged mice, AM from an acute exacerbation exhibited significantly enhanced expression of markers of alternative activation, together with enhanced expression of proinflammatory cytokines and of cell surface proteins associated with antigen presentation. In parallel, there was markedly increased expression of both mRNA and immunoreactivity for IL-33 in the airways. Neutralization of IL-33 significantly decreased both airway inflammation and the expression of proinflammatory cytokines by AM. Collectively, these data indicate that in this model of an acute exacerbation of chronic asthma, IL-33 drives activation of AM and has an important role in the pathogenesis of airway inflammation.

The molecular mechanisms of glucocorticoids-mediated neutrophil survival

Neutrophil-dominated inflammation plays an important role in many airway diseases including asthma, chronic obstructive pulmonary disease (COPD), bronchiolitis and cystic fibrosis. In cases of asthma where neutrophil-dominated inflammation is a major contributing factor to the disease, treatment with corticosteroids can be problematic as corticosteroids have been shown to promote neutrophil survival which, in turn, accentuates neutrophilic inflammation. In light of such cases, novel targeted medications must be developed that could control neutrophilic inflammation while still maintaining their antibacterial/anti-fungal properties, thus allowing individuals to maintain effective innate immune responses to invading pathogens. The aim of this review is to describe the molecular mechanisms of neutrophil apoptosis and how these pathways are modulated by glucocorticoids. These new findings are of potential clinical value and provide further insight into treatment of neutrophilic inflammation in lung disease.

Preventing asthma exacerbations: what are the targets?

Exacerbations of asthma are the main cause of asthma morbidity. They induce acute respiratory failure, and sometimes death. Two immunological signals acting in synergy are necessary for inducing asthma exacerbations. The first, triggered by allergens and/or unknown agents leads to the chronic Th2 inflammation characteristic of asthma. The second, caused by either viral infection, allergens, pollutants or a combination of these, results in an acute Th1 and Th2 inflammation precipitating symptoms. In both, innate and adaptive immunities are involved, providing a series of potential targets for therapy. Molecules associated to the first, chronic inflammation constitute targets for preventing therapies, when these related to the second, acute signal provide the rationale for curative treatments. Toll like receptors and bronchial epithelial cell-derived cytokines, engaged upstream of inflammation constitute interesting candidates for future treatments. The great heterogeneity of asthma has to be taken into account when considering targets for therapy to identify clusters of responders and nonresponders, and an integrative system biology approach will be necessary to go further.

[Adult asthma exacerbations in questions]

In this article a French working party critically review the international literature to revise the definition, pathophysiology, treatment and cost of exacerbations of adult asthma. The various guidelines do not always provide a consistent definition of exacerbations of asthma. An exacerbation can be defined as deterioration of clinical and/or functional parameters lasting more than 24 hours, without return to baseline, requiring a change of treatment. No single clinical or functional criterion can be used as an early marker of an exacerbation. Innate and acquired immune mechanisms, modified by contact with infectious, irritant or allergenic agents, participate in the pathogenesis of exacerbations, which are accompanied by bronchial inflammation. In 2010, mortality is related to progression of exacerbations, often occurring before the patient seeks medical attention. The objective of treatment is to control asthma and prevent exacerbations. However, many factors can trigger exacerbations and often cannot be controlled. The efficacy of inhaled corticosteroids has been demonstrated on reduction of the number of exacerbations and the number of asthma-related deaths. This treatment is cost-effective, especially in terms of reduction of exacerbations.

Alveolar macrophages stimulate enhanced cytokine production by pulmonary CD4+ T-lymphocytes in an exacerbation of murine chronic asthma

The mechanisms underlying the exaggerated distal airway inflammation and hyperresponsiveness that characterize acute exacerbations of asthma are largely unknown. Using BALB/c mouse experimental models, we demonstrated a potentially important role for alveolar macrophages (AM) in the development of an allergen-induced exacerbation of asthma. To induce features of airway inflammation and remodeling characteristic of mild chronic asthma, animals were systemically sensitized and exposed to low mass concentrations (≈3 mg/m(3)) of aerosolized ovalbumin for 30 minutes per day, 3 days per week, for 4 weeks. A subsequent single moderate-level challenge (≈30 mg/m(3)) was used to trigger an acute exacerbation. In chronically challenged animals, cytokine expression by AM was not increased, whereas after an acute exacerbation, AM exhibited significantly enhanced expression of proinflammatory cytokines, including interleukin (IL) 1β, IL-6, CXCL-1, and tumor necrosis factor α. In parallel, there was a marked increase in the expression of several cytokines by CD4(+) T-lymphocytes, notably the Th2 cytokines IL-4 and IL-13. Importantly, AM from an acute exacerbation stimulated the expression of Th2 cytokines when cocultured with CD4(+) cells from chronically challenged animals, and their ability to do so was significantly greater than AM from either chronically challenged or naïve controls. Stimulation was partly dependent on interactions involving CD80/86. We conclude that in an acute exacerbation of asthma, enhanced cytokine expression by AM may play a critical role in triggering increased expression of cytokines by pulmonary CD4(+) T-lymphocytes.

Eosinophil protein in airway macrophages: a novel biomarker of eosinophilic inflammation in patients with asthma

BACKGROUND

Noneosinophilic asthma is common across asthma severities. However, in patients with moderate-to-severe disease, the absence of sputum eosinophilia cannot distinguish between asthmatic subjects with eosinophilic inflammation controlled by corticosteroids versus those in whom eosinophilic inflammation is not a component of the disease.

OBJECTIVES

We sought to develop a method to quantify eosinophil proteins in airway macrophages as a novel biomarker of eosinophilic airway inflammation.

METHODS

Eosinophil proteins in airway macrophages were assessed by means of flow cytometry, immunofluorescence, and cytoplasmic hue change after ingestion of apoptotic eosinophils. Airway macrophage median percentage of red-hued area in stained sputum cytospin preparations was assessed by means of image analysis from (1) subjects with mild-to-severe asthma, subjects with nonasthmatic eosinophilic bronchitis, and healthy control subjects; (2) subjects with eosinophilic severe asthma after treatment with prednisolone; and (3) subject with noneosinophilic asthma before corticosteroid withdrawal.

RESULTS

Eosinophil proteins were detected in airway macrophages, and cytoplasmic red hue increased after ingestion of apoptotic eosinophils. Airway macrophage percentage redhued area was increased in subjects with moderate-to-severe asthma compared with that seen in subjects with mild asthma and healthy control subjects, was similar in those with or without a sputum eosinophilia, and was increased after corticosteroid therapy. In asthmatic subjects without sputum eosinophilia, the airway macrophage percentage red-hued area was increased in subjects who did versus those who did not have sputum eosinophilia after corticosteroid withdrawal.

CONCLUSIONS

Eosinophil proteins can be reliably measured in airway macrophages. In combination with sputum eosinophilia, the macrophage eosinophil protein content might further define the asthma phenotype and provide an additional tool to direct therapy.

Monitoring asthma therapy using indirect bronchial provocation tests

OBJECTIVES

Bronchial provocation tests that assess airway hyperresponsiveness (AHR) are known to be useful in assisting the diagnosis of asthma and in monitoring inhaled corticosteroid therapy. We reviewed the use of bronchial provocation tests that use stimuli that act indirectly for monitoring the benefits of inhaled corticosteroids.

DATA SOURCE

Published clinical trials investigating the effect of inhaled corticosteroids on bronchial hyperresponsiveness in persons with asthma were used for this review.

STUDY SELECTION

Studies using indirect stimuli to provoke airway narrowing such as exercise, eucapnic voluntary hyperventilation, cold air hyperventilation, hypertonic saline, mannitol, or adenosine monophosphate (AMP) to assess the effect of inhaled corticosteroids were selected.

RESULTS

Stimuli acting indirectly result in the release of a variety of bronchoconstricting mediators such as leukotrienes, prostaglandins, and histamine, from cells such as mast cells and eosinophils. A positive response to indirect stimuli is suggestive of active inflammation and AHR that is consistent with a diagnosis of asthma. Persons with a positive response to indirect stimuli benefit from daily treatment with inhaled corticosteroids. Symptoms and lung function are not useful to predict the long-term success of inhaled corticosteroid dose as they usually resolve rapidly, and well before inflammation and AHR has resolved. Following treatment, AHR to indirect stimuli is attenuated. Further, during long-term treatment, asthmatics can become as non-responsive as non-asthmatic healthy persons, suggesting that asthma is not active.

CONCLUSIONS

Non-responsiveness to indirect bronchial provocation tests following inhaled corticosteroids occurs weeks to months following the resolution of symptoms and lung function. Non-responsiveness to indirect stimuli may provide a goal for adequate therapy with inhaled corticosteroids.

Tumor necrosis factor-alpha in severe corticosteroid-refractory asthma

Tumor necrosis factor (TNF)-alpha is a proinflammatory cytokine. Blocking TNF-alpha has been demonstrated to be effective in various diseases, including both rheumatoid and psoriatic arthritis. There is evidence to show that levels of TNF-alpha are elevated in patients with severe asthma. TNF-alpha is involved in the initiation and perpetuation of the inflammatory process, epithelial damage and remodeling, and mucin hypersecretion. Furthermore, TNF-alpha polymorphism has also been reported in the asthmatic population. Based on the necessity for alternative treatments for asthmatics with severe disease and those who are particularly resistant to conventional asthma therapy, it has been shown that molecules targeted at blocking the effects of TNF-alpha probably constitute a considerable advance in the management of these difficult patients. This review focuses on the evidence of TNF-alpha axis upregulation in severe corticosteroid-refractory asthma, as well as the role of TNF-alpha inhibition and the adverse effects of treatment.

Biomarkers in asthma and allergic rhinitis

A biological marker (biomarker) is a physical sign or laboratory measurement that can serve as an indicator of biological or pathophysiological processes or as a response to a therapeutic intervention. An applicable biomarker possesses the characteristics of clinical relevance (sensitivity and specificity for the disease) and is responsive to treatment effects, in combination with simplicity, reliability and repeatability of the sampling technique. Presently, there are several biomarkers for asthma and allergic rhinitis that can be obtained by non-invasive or semi-invasive airway sampling methods meeting at least some of these criteria. In clinical practice, such biomarkers can provide complementary information to conventional disease markers, including clinical signs, spirometry and PC(20)methacholine or histamine. Consequently, biomarkers can aid to establish the diagnosis, in staging and monitoring of the disease activity/progression or in predicting or monitoring of a treatment response. Especially in (young) children, reliable, non-invasive biomarkers would be valuable. Apart from diagnostic purposes, biomarkers can also be used as (surrogate) markers to predict a (novel) drug's efficacy in target populations. Therefore, biomarkers are increasingly applied in early drug development. When implementing biomarkers in clinical practice or trials of asthma and allergic rhinitis, it is important to consider the heterogeneous nature of the inflammatory response which should direct the selection of adequate biomarkers. Some biomarker sampling techniques await further development and/or validation, and should therefore be applied as a "back up" of established biomarkers or methods. In addition, some biomarkers or sampling techniques are less suitable for (very young) children. Hence, on a case by case basis, a decision needs to be made what biomarker is adequate for the target population or purpose pursued. Future development of more sophisticated sampling methods and quantification techniques, such as--omics and biomedical imaging, will enable detection of adequate biomarkers for both clinical and research applications.

Measuring exacerbations in obstructive lung disease

PURPOSE

Using hospitalization always has been seen as a solid measurement for exacerbation in pharmacoepidemiology, but might lead to an underestimation of disease exacerbation because of a trend towards outpatient care. The aim of this study was to quantify the incidence of different exacerbation markers in obstructive lung disease and to identify predictors for these exacerbation markers.

METHODS

We conducted a cohort study using the PHARMO record linkage system, including demographic details and complete medication histories of more than two million community-dwelling residents in the Netherlands from 1985 onwards. Eligible patients were adult users of inhaled corticosteroids (ICS). Outcome parameters were hospitalization and short courses of systemic corticosteroids. Patients were allowed to have multiple exacerbations during follow-up.

RESULTS

We identified 5327 patients. During follow-up, 8635 exacerbations occurred in 2332 patients with a trend in time towards treating exacerbations out of the hospital (p-value 0.003). Of all patients with exacerbations, 73% was not hospitalized during follow-up. Exacerbations were associated with high-dose ICS use (adjusted RR 1.4; 95% CI 1.2-1.7) and chronic systemic corticosteroid use (adjusted RR 1.9; 95%CI 1.6-2.2).

CONCLUSIONS

Using hospitalization only as exacerbation marker leads to underestimating the exacerbation rate, because of exacerbation treatment out of the hospital. Patients with obstructive lung disease using chronic systemic corticosteroids or high-dose ICS use are more prone to exacerbations. This implies that these patients should be monitored carefully to prevent recurrent exacerbations which are detrimental for their prognosis and quality of life.

Use of exhaled nitric oxide measurement to identify a reactive, at-risk phenotype among patients with asthma

RATIONALE

Exhaled nitric oxide (Fe(NO)) is a biomarker of airway inflammation in mild to moderate asthma. However, whether Fe(NO) levels are informative regarding airway inflammation in patients with severe asthma, who are refractory to conventional treatment, is unknown. Here, we hypothesized that classification of severe asthma based on airway inflammation as defined by Fe(NO) levels would identify a more reactive, at-risk asthma phenotype.

METHODS

Fe(NO) and major features of asthma, including airway inflammation, airflow limitation, hyperinflation, hyperresponsiveness, and atopy, were determined in 446 individuals with various degrees of asthma severity (175 severe, 271 non-severe) and 49 healthy subjects enrolled in the Severe Asthma Research Program.

MEASUREMENTS AND MAIN RESULTS

Fe(NO) levels were similar among patients with severe and non-severe asthma. The proportion of individuals with high Fe(NO) levels (>35 ppb) was the same (40%) among groups despite greater corticosteroid therapy in severe asthma. All patients with asthma and high Fe(NO) had more airway reactivity (maximal reversal in response to bronchodilator administration and by methacholine challenge), more evidence of allergic airway inflammation (sputum eosinophils), more evidence of atopy (positive skin tests, higher serum IgE and blood eosinophils), and more hyperinflation, but decreased awareness of their symptoms. High Fe(NO) identified those patients with severe asthma characterized by the greatest airflow obstruction and hyperinflation and most frequent use of emergency care.

CONCLUSIONS

Grouping of asthma by Fe(NO) provides an independent classification of asthma severity, and among patients with severe asthma identifies the most reactive and worrisome asthma phenotype.

Medication changes prior to hospitalization for obstructive lung disease: a case-crossover study

BACKGROUND

Hospitalizations have always been seen as a solid outcome parameter in pharmacoepidemiology. However, the period leading to hospitalization and prehospital management of the patient are equally important.

OBJECTIVE

To evaluate medication changes in the period prior to hospitalization for obstructive lung disease and to quantify the association between medication use and the risk of hospitalization.

METHODS

We conducted a case-crossover study using the PHARMO record linkage system, which contains drug dispensing data from community pharmacies and hospital admission data. Patients included in the study were adults hospitalized for obstructive lung disease between 2005 and 2007. The index date of the case period was the date of hospitalization, and control moments were set at 3, 6, 9, and 12 months before admission. For each patient, all prescriptions prior to the date of hospitalization were identified. Medication use was ascertained in a 90-day time window prior to each case or control moment.

RESULTS

We identified 1481 patients who were hospitalized for obstructive lung disease. It appeared that respiratory medication use increased in the 90 days prior to hospitalization. Hospitalization was associated with the use of 3 or more respiratory drugs (OR 2.2; 95% CI 1.8 to 2.8), systemic glucocorticoids (OR 4.5; 95% CI 3.8 to 5.4), and antibiotics (OR 3.1; 95% CI 2.7 to 3.6).

CONCLUSIONS

The use of systemic glucocorticoids, antibiotics, and other respiratory drugs increased prior to hospitalization for obstructive lung disease. These results could be indicative of the development and/or treatment of an exacerbation. There is a need for markers to detect exacerbations in an early phase in order to start treatment as early as possible and possibly prevent hospitalizations for obstructive lung disease.

Increased vascular permeability precedes cellular inflammation as asthma control deteriorates

BACKGROUND

Airway microcirculation is abnormal in asthma but the role of vascular changes in asthma deteriorations remains poorly defined. We prospectively assessed the vascular changes accompanying worsening of asthma control by using an inhaled corticosteroid (ICS) dose-reduction model.

OBJECTIVES

To evaluate airway vascularity, vascular permeability and expression of vascular endothelial growth factor (VEGF) in early asthma deterioration induced by ICS back-titration.

METHODS

Twenty mild-to-moderate persistent symptomatic asthmatics on low-to-moderate ICS were recruited and treated with 4 weeks of high-dose fluticasone propionate (1000 microg/day) to achieve symptom control. This was followed by dose reduction to half of the pre-study doses for 4-8 weeks until the symptoms began to return. Endobronchial biopsy and bronchoalveolar lavage (BAL) samples were obtained after both treatment periods.

RESULTS

Vascularity as measured by the number and size of blood vessels, as well as VEGF expression did not change following ICS reduction. Even on high-dose ICS, perivascular albumin staining and BAL microalbumin levels in asthmatic subjects, as markers of permeability, were elevated when compared with normal subjects and both further increased significantly after ICS reduction. There was a significant association between changes in vascular leakiness and clinical deterioration. Increases in airway albumin correlated with previously reported increases in airway wall infiltration with T lymphocytes.

CONCLUSIONS

Our results suggest that airway vascular leakage is a major pathophysiologic feature of early asthma deterioration, occurring before recrudescence of cellular inflammation.

Non-invasive markers of airway inflammation and remodeling in childhood asthma

To evaluate the relationship between pro-inflammatory and pro-remodeling mediators and severity and control of asthma in children, the levels of IL-8, MMP-9, TIMP-1 in induced sputum supernatants, the number of sputum eosinophils, as well as FeNO, were investigated in 35 asthmatic children, 12 with intermittent (IA) and 23 with moderate asthma (MA), and 9 controls (C). The patients with asthma were followed for 1 yr and sputum was obtained twice during the follow-up. Biomarker levels were correlated with the number of exacerbations. We found that IL-8, MMP-9, TIMP-1 and the numbers of eosinophils in induced sputum, as well as FeNO, were increased in children with IA and MA in comparison to C. The ongoing inflammation was confirmed by increased nuclear p65 NF-kappaB subunit localization in sputum cells. In MA, FeNO measurements, sputum eosinophils and IL-8 levels, positively correlated with the occurrence of disease exacerbations during a 1-yr follow-up. According to FeNO, sputum eosinophils and IL-8 sputum concentrations, and the number of exacerbations, two distinct phenotypes of MA were identified. This study shows that the presence of bronchial inflammation is detectable in the airways of some IA, as well as in the airways of MA, despite the regular ICS treatment. This study also proposes the need to perform large prospective studies to confirm the importance of measuring specific biomarkers in induced sputum, concomitantly to FeNO analyses, to assess sub-clinical airway inflammation and disease control in children with asthma.

Human airway smooth muscle cells from asthmatic individuals have CXCL8 hypersecretion due to increased NF-kappa B p65, C/EBP beta, and RNA polymerase II binding to the CXCL8 promoter

CXCL8 is a neutrophil and mast cell chemoattractant that is involved in regulating inflammatory cell influx in asthma. Here, we investigated the transcriptional mechanism involved in CXCL8 induction by TNF-alpha in cultured human airway smooth muscle (HASM) cells and compared these in cells from nonasthmatic and asthmatic individuals. Transfection studies with mutated CXCL8 promoter constructs identified NF-kappaB, activating protein-1, and CAAT/enhancer binding protein (C/EBP)beta as key transcription factors, and binding of these three transcription factors to the CXCL8 promoter after TNF-alpha stimulation was confirmed by chromatin immunoprecipitation analysis. Cells derived from asthmatic individuals produced significantly higher levels of CXCL8 than nonasthmatic cells both basally and following 24 h of stimulation with TNF-alpha (p < 0.001). Furthermore, chromatin immunoprecipitation studies detected increased binding of NF-kappaB p65 and RNA polymerase II to the CXCL8 promoter of asthmatic HASM cells both in the presence and absence of TNF-alpha stimulation. This was not due to either an increased activation or phosphorylation of NF-kappaB per se or to an increase in its translocation to the nucleus. Increased binding of C/EBPbeta to the CXCL8 promoter of unstimulated cells was also detected in the asthmatic HASM cells. Collectively these studies show that HASM cells from asthmatic individuals have increased CXCL8 production due to the presence of a transcription complex on the CXCL8 promoter, which contains NF-kappaB, C/EBPbeta, and RNA polymerase II. This is the first description of an abnormality in transcription factor binding altering chemokine expression in airway structural cells in asthma.

The predictive value of eosinophil cationic protein and lactate dehydrogenase in asthma: a comparative study of serum versus sputum

BACKGROUND

: Serum and sputum eosinophil cationic protein (ECP) levels are correlated with asthma disease severity.

OBJECTIVE

: To establish a diagnostic accuracy of ECP and lactate dehydrogenase (LDH) in serum (indirectly) and sputum (directly) as inflammatory markers in asthma.

PATIENTS AND METHODS

: In a cross sectional study, 76 asthmatic patients with exacerbation were enrolled in the study. ECP was determined using enzyme linked immuno-assay.

RESULTS

: Asthmatic patients compared with control subjects, had a significant higher levels of ECP and LDH in sputum. Both sputum and serum ECP and LDH were reduced significantly with prednisolone treatment. FEV1 was inversely correlated with sputum ECP, serum ECP, and sputum LDH. A significant positive correlation was noted between sputum ECP and sputum LDH. Serum LDH does not demonstrate any significant correlations with other variables. The area under receiver operating characteristic curve showed that sputum ECP (0.92) was a significantly an accurate marker more than serum ECP (0.81), sputum (0.80) LDH, and serum (0.65) LDH. Furthermore, the area under curve was lower for serum ECP (0.81) than that for sputum ECP (0.92). However, serum ECP (0.81) was more accurate marker than serum LDH (0.65).

CONCLUSION

: Serum and sputum ECP as eosinophilic inflammatory markers are associated with poor asthma control. Sputum ECP and LDH were significantly an accurate markers more than serum ECP and LDH.

Inhaled corticosteroids as combination therapy with beta-adrenergic agonists in airways disease: present and future

Inhaled corticosteroid (ICS) therapy in combination with long-acting beta-adrenergic agonists represents the most important treatment for chronic airways diseases such as asthma and chronic obstructive pulmonary disease (COPD). ICS therapy forms the basis for treatment of asthma of all severities, improving asthma control, lung function and preventing exacerbations of disease. Use of ICS has also been established in the treatment of COPD, particularly symptomatic patients, who experience useful gains in quality of life, likely from an improvement in symptoms such as breathlessness and in reduction in exacerbations, and an attenuation of the yearly rate of deterioration in lung function. The addition of long-acting beta-agonist (LABA) therapy with ICS increases the efficacy of ICS effects in moderate-to-severe asthma. Thus, a 800 mug daily dose of the ICS budesonide reduced severe exacerbation rates by 49% compared to a low dose of 200 mug daily, and addition of the LABA formoterol to budesonide (800 mug) led to a 63% reduction. In COPD, the effects of ICS are less prominent but there are beneficial effects on the decline in FEV(1) and the rate of exacerbations. A reduction in the rate of decline in FEV(1) of 16 ml/year with a 25% reduction in exacerbation rate has been reported with the salmeterol and fluticasone combination. A non-significant 17.5% reduction in all-cause mortality rate with ICS and LABA is reported. Chronic inflammation is a feature of both asthma and COPD, although there are site and characteristic differences. ICS targets this inflammation although this effect of ICS is less effective in patients with severe asthma and with COPD; however, addition of LABA may potentiate the anti-inflammatory effects of ICS. An important consideration is the presence of corticosteroid insensitivity in these patients. Currently available ICS have variably potent binding activities to specific glucocorticoid receptors, leading to inhibition of gene expression by either binding to DNA and inducing anti-inflammatory genes or by repressing the induction of pro-inflammatory mediators. Local side effects of ICS include oral candidiasis, hoarseness and dysphonia, while systemic side effects, such as easy bruising and reduction in growth velocity or bone mineral densitometry, are usually restricted to doses above maximally recommended doses. Use of LABA alone in patients with asthma increases the risk of asthma-related events including deaths, but this is less observed with the combination of ICS and LABA. Therefore, use of LABA alone is not recommended for asthma therapy. Future progress in ICS development will be characterised by the introduction of ICS with greater efficacy with a limited side-effect profile, and by longer-acting ICS that can be used in combination with once-daily LABAs. Other agents that could improve the efficacy of corticosteroids or reverse corticosteroid insensitivity may be added to ICS. ICS in combination with LABAs will continue to remain the main focus of treatment of airways diseases.

Similar efficacy of ciclesonide versus prednisolone to treat asthma worsening after steroid tapering

RATIONALE

Oral corticosteroids effectively treat asthma exacerbations but are associated with well-described side effects.

OBJECTIVE

This study compared the efficacy and safety of a high dose of an inhaled corticosteroid with oral prednisolone in patients with worsening of their asthma after medication withdrawal.

METHODS

Patients tapered off their inhaled corticosteroids until they reached predefined criteria of "worsening asthma". Randomized patients (n=130) were treated double blind with either ciclesonide 800mug twice daily (starting with 800mug hourly for 3h after randomization) or prednisolone 40mg once daily for 2 weeks. Spirometry, daily asthma symptoms, morning and evening peak expiratory flow and blood parameters were assessed in all, methacholine challenge and inflammatory measures were determined in induced sputum in a subset of patients.

RESULTS

Ciclesonide was as effective as prednisolone in improving forced expiratory flow in 1s, morning peak expiratory flow and symptoms, the latter improving more rapidly with ciclesonide. No differences were found in methacholine responsiveness or inflammatory measures in sputum or blood. Ciclesonide caused significantly less reduction in morning plasma cortisol levels (p<0.0001).

CONCLUSION

This study shows that inhaled ciclesonide (800mug twice daily) has comparable efficacy to oral prednisolone (40mg once daily) to regain asthma control in patients with asthma worsening. The more rapid onset and smaller effect on cortisol suppression suggest a better safety profile of ciclesonide.

Relation between inflammation and symptoms in asthma

Asthma symptoms are the main reason for healthcare utilization and are a fundamental parameter for the evaluation of asthma control. Currently, asthma is defined as a chronic inflammatory disease. A French expert group studied the association between inflammation and asthma symptoms by carrying out a critical review of the international literature. Uncontrolled asthmatics have an increased number of polynuclear eosinophils in the induced sputum and an increased production of exhaled NO. Control by anti-inflammatory treatment is accompanied by a reduction in bronchial eosinophilia and exhaled NO. Asthma symptoms are the result of complex mechanisms and many factors modify their perception. Experimental data suggest that there is a relationship between the perception of symptoms and eosinophilic inflammation and that inhaled corticoid therapy improves this perception. Although they are still not applicable in routine practice, follow-up strategies based on the evaluation of inflammation are thought to be more effective in reducing exacerbations than those usually recommended based on symptoms and sequential analysis of respiratory function. Inhaled corticosteroid therapy is the reference disease-modifying therapy for persistent asthma. Recent studies demonstrated that adjustment of anti-inflammatory treatment based on symptoms is an effective strategy to prevent exacerbations and reduce the total number of doses of inhaled corticosteroids.

Managing patients with chronic severe asthma: rise to the challenge

Most asthmatic patients with moderate to severe disease can be satisfactorily managed with a combination of inhaled corticosteroids and beta(2)-agonists. However, there are perhaps 10% of the asthmatic population with persistent symptoms, impaired quality of life and excessive health-care utilization, despite this management regime. These patients often require frequent and even occasionally regular oral corticosteroid use. Chronic, severe asthma is a heterogeneous disease with distinct sub-phenotypes. A systematic diagnostic work-up may help to identify these distinct sub-phenotypes and this may help guide treatment and may even provide information about prognosis. Optimal treatment of chronic severe asthma should achieve the best possible asthma control and quality of life with the least dose of systemic corticosteroids. The choice and formulation of therapeutic agent is dictated by the severity of disease and includes conventional, immunosuppressive/immunomodulating and biologic therapies. Unfortunately, current asthma management guidelines offer little contribution to the care of the challenging patient with chronic severe asthma. This review article aims at summarizing the evidence regarding various therapeutic modalities for chronic severe asthma and also aims to provide a practical approach to diagnosis and management for the benefit of those who have a specific interest in this problematic condition.

[The relationship between inflammation and symptoms in asthma]

In asthma, symptoms are the main reason for recourse to healthcare and are a fundamental parameter for the evaluation of asthma control. Currently, asthma is defined as a chronic inflammatory disease. Uncontrolled asthmatics have an increased number of eosinophils in induced sputum and an increased production of exhaled NO. Control by anti-inflammatory treatment is accompanied by a reduction in bronchial eosinophilia and exhaled NO. Asthma symptoms are the result of complex mechanisms and many factors modify their perception. Experimental data suggests that there is a relationship between the perception of symptoms and eosinophilic inflammation, and that inhaled corticoid therapy improves this perception. Although they are still not applicable in routine practice, follow-up strategies based on the evaluation of inflammation are thought to be more effective in reducing exacerbations than those usually recommended based on retrospective evaluation of symptoms and sequential analysis of respiratory function. Inhaled corticosteroid therapy is the reference maintenance therapy for persistent asthma and adjustment of anti-inflammatory treatment based on symptoms is an effective strategy to prevent exacerbations and reduce the total dose of inhaled corticosteroids. A French expert group has undertaken a study of the association between inflammation and asthma symptoms by carrying out a critical review of the international literature.

Bacterial DNA delays human eosinophil apoptosis

Oligodeoxynucleotide (ODN) sequences containing unmethylated cytidine phosphate guanosine (CpG) motifs prevalent in bacterial DNA attenuate allergic lung inflammation in experimental models of asthma but failed to inhibit eosinophilia and improve lung function in patients with asthma. Bacterial respiratory tract infections exacerbate asthma in humans. Increased eosinophil survival is a critical factor leading to persistent eosinophilic airway inflammation. Apoptosis is regarded as a key mechanism in the resolution of eosinophilic inflammation. The aim of this study was to investigate the effects of bacterial DNA and CpG ODNs on human eosinophil apoptosis in vitro and to elucidate the signalling pathway. Eosinophils were isolated from human peripheral blood by CD16- or CD16-, CD19- and CD304-negative selection. Apoptosis was determined by flow cytometric analysis of relative DNA content, Annexin-V staining and/or morphological analysis. Toll-like receptor 9 (TLR9) expression was studied by using western blotting and intracellular flow cytometry. Bacterial DNA and phosphorothioate-modified CpG ODNs, but not vertebrate DNA, were found to delay spontaneous eosinophil apoptosis. The effect of CpG ODNs was dependent on endosomal acidification and reversed by inhibitory ODN, which suggests involvement of TLR9 pathway. Furthermore, we demonstrated TLR9 expression in eosinophils derived from both atopic and healthy donors. Non-CpG ODNs had occasionally parallel but less profound effect on eosinophil apoptosis, which was not dependent on endosomal acidification. The anti-apoptotic effect of CpG ODNs was dependent on phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappaB (NF-kappaB) but not mitogen-activated protein kinases (MAPKs) as determined by inhibitor studies. Although our results suggest CpG-dependent involvement of TLR9 in the action of phosphorothioate-modified ODNs, we interestingly found that the anti-apoptotic action of native bacterial DNA in eosinophils is not dependent on unmethylated CpG motifs. This suggests that bacterial DNA contains a currently unknown recognition structure lacking from vertebrate DNA. Bacterial DNA-mediated suppression of eosinophil apoptosis is a novel mechanism for exacerbation of eosinophilic lung inflammation associated with bacterial respiratory tract infection.

Clinical significance of eosinophilic cationic protein levels in nasal secretions of patients with nasal polyposis

Nasal polyps are characterized by eosinophilic infiltration, and frequently coexist with asthma, aspirin intolerance and allergy. Eosinophilic cationic protein (ECP) is a specific eosinophil granule protein released upon activation of eosinophils. We investigated the ECP levels in nasal secretions of patients with nasal polyposis (NP) in order to correlate them with disease severity and associated diseases and to compare ECP levels between patients with and without recurrence of NP after surgical treatment. A total of 78 patients who had surgery for NP were followed up for a minimum of 18 months. The presence of asthma, allergies or aspirin intolerance was noted. Nasal secretions were obtained 1 day before the surgery and during the follow-up period after surgery. Immunoassays were used to quantify ECP in nasal secretions and serum and interleukin (IL)-5 in nasal secretions. ECP levels in nasal secretions were higher in patients with asthma or aspirin intolerance than in patients without asthma or aspirin intolerance, while no significant differences were found between allergic and non-allergic patients. ECP levels in nasal secretions correlated significantly with IL-5 levels in nasal secretions, the degree of tissue eosinophilia and computed tomographic (CT) scores. In total, 30 patients (38%) developed recurrent NP during the follow-up period. Preoperative ECP and IL-5 levels in nasal secretions were significantly higher in patients with recurrence compared to patients without recurrence. During the follow-up period, patients without recurrence demonstrated a significant reduction in the ECP levels in nasal secretions, whereas there was no significant reduction in the ECP levels of patients with recurrence. The results of this study provide evidence that ECP levels in nasal secretions of patients with NP correlate with the presence of asthma or aspirin intolerance and severity of NP determined by CT scores.

Prognosis of adult asthma after normalization of bronchial hyperresponsiveness by inhaled corticosteroid therapy

BACKGROUND

Inhaled corticosteroids (ICSs) are the most effective anti-inflammatory drugs for adult asthma and can improve not only clinical symptoms but also bronchial hyperresponsiveness (BHR). However, the prognosis of adult asthma has not been well studied, and it remains to be elucidated precisely how long treatment with ICSs should be continued once clinical remission is achieved.

OBJECTIVES

We examined whether ICS use could be withdrawn or reduced without exacerbation of disease.

METHODS

We retrospectively studied 374 adult patients with asthma to determine which factors predicted the elimination or reduction of ICS treatment without exacerbations of disease after the achievement of normalized BHR to acetylcholine. The patients were classified into three groups: Group 1 had symptoms within 6 months of normalization and needed to continue therapy; group 2 received the equivalent of >or= 400 microg fluticasone propionate until BHR normalization, did not have symptoms in the 6 months after normalization, and then had their doses of ICSs halved; and group 3 received the equivalent of <or= 200 microg fluticasone propionate at an enrollment, did not have symptoms in the 6 months after normalization, and then had all ICSs withdrawn. The primary outcome measure was the presence of clinical symptoms. We used multiple logistic regression and a Kaplan-Meier analysis to analyze the factors predicting remission.

RESULTS

Twenty-nine patients in group 3 remained asymptomatic for more than 30 months (mean 47.1 +/- 12.4 months) after discontinuing ICS therapy. The predictive markers of remission were low levels of eosinophils in the sputum, high %V(50) at the first hospital visit, and the need for only a low daily dose of ICS to induce normalized BHR. Conversely, patients with severe BHR at the first hospital visit, low %FEV(1) at normalized BHR, and a need for high-dose ICSs to reach normalized BHR could not reduce or discontinue treatments.

CONCLUSION

Some adult patients with asthma whose BHR is normalized by ICS therapy can achieve remission from disease exacerbation after discontinuation of ICSs. However, patients with severe asthma or asthma of long duration may not achieve remission even if their BHR is normalized.

Steroid-resistant neutrophilic inflammation in a mouse model of an acute exacerbation of asthma

Neutrophilic inflammation in acute exacerbations of asthma tends to be resistant to treatment with glucocorticoids. This may be related to decreased activity and expression of histone deacetylase-2 (HDAC2), which down-regulates expression of proinflammatory genes via recruitment to the glucocorticoid receptor complex. We assessed airway inflammation and response to steroid treatment in a novel mouse model of an acute exacerbation of chronic asthma. Systemically sensitized mice received low-level challenge with aerosolized ovalbumin for 4 weeks, followed by a single moderate-level challenge to induce enhanced inflammation in distal airways. We assessed the effects of pre-treatment with dexamethasone on the accumulation of inflammatory cells in the airways, airway responsiveness to methacholine, expression and enzymatic activity of nuclear proteins including histone acetyl transferase (HAT) and HDAC2, and levels of transcripts for neutrophil chemoattractant and survival cytokines. Dexamethasone suppressed inflammation associated with eosinophil and T-lymphocyte recruitment, but did not prevent neutrophil accumulation or development of airway hyperresponsiveness. Increased activity of HAT was suppressed by steroid treatment, but the marked diminution of HDAC2 activity and increased activity of nuclear factor-kappaB were not reversed. Correspondingly, elevated expression of mRNA for TNF-alpha, granulocyte-macrophage colony-stimulating factor, IL-8, and p21(waf) were also not suppressed by dexamethasone. Levels of lipid peroxidation and protein nitration products were elevated in the acute exacerbation model. We conclude that impaired nuclear recruitment of HDAC2 could be an important mechanism of steroid resistance of the neutrophilic inflammation in exacerbations of asthma. Oxidative stress may contribute to decreased HDAC2 activity.

Methods used in clinical development of novel anti-asthma therapies

In recent years, it has become increasingly important to get as much as possible information on clinical efficacy already in the early phases of drug development. For proof of concept (POC) studies testing novel anti-inflammatory drugs in asthma, there are several validated exacerbation models, inducing various aspects of the airway inflammation and airway responsiveness. The choice of the appropriate asthma model depends on the drug's targets within the inflammatory process. For adequate assessment of the drug's anti-inflammatory potential, it is crucial to choose adequate (surrogate) biomarkers. Ideally, these should include measures of airway response, central and peripheral airway inflammation and airway hyperresponsiveness. Overall, there are validated non-invasive sampling techniques for the measurement of inflammatory markers in asthma that can be applied as outcome parameters in early clinical trials. If adequately implemented, these measurements can provide early indication of proof of pharmacological and potential therapeutic efficacy-even in first administration to humans.

Phosphatidylinositol 3-kinase and p38 mitogen-activated protein kinase regulate induction of Mcl-1 and survival in glucocorticoid-treated human neutrophils

BACKGROUND

Glucocorticoids have been shown to inhibit human neutrophil apoptosis, with implications that this might help accentuate neutrophilic inflammation.

OBJECTIVE

The aim of this study was to investigate the molecular mechanisms involved in glucocorticoid-mediated inhibition of primary human neutrophil apoptosis.

METHODS

Primary human neutrophils were isolated from peripheral blood of healthy volunteers and cultured in vitro with dexamethasone.

RESULTS

Here we confirm that dexamethasone, a classical glucocorticoid, significantly inhibited apoptosis of primary human neutrophils. This inhibition was not dependent on transrepression of proapoptotic molecules but was associated with induction of antiapoptotic Mcl-1. Remarkably, glucocorticoid-mediated enhancement of Mcl-1 and survival were significantly suppressed by pharmacologic inhibition of p38 mitogen-activated protein kinase or phosphatidylinositol 3-kinase. Inhibition of the above kinases also blocked glucocorticoid-induced maintenance of mitochondrial transmembrane potential and suppression of caspases.

CONCLUSION

Phosphatidylinositol 3-kinase and p38 mitogen-activated protein kinase are protein kinases that regulate the prosurvival effect of glucocorticoids on human neutrophils.

Loss of Control of Asthma Following Inhaled Corticosteroid Withdrawal Is Associated With Increased Sputum Interleukin-8 and Neutrophils

BACKGROUND

The role of neutrophils in exacerbations of asthma is poorly understood. We examined the effect of withdrawal of inhaled corticosteroids on sputum inflammatory indexes in a double-blind study in patients with moderate, stable asthma.

METHODS

Following a 2-week run in period, 24 subjects were randomized to receive either budesonide (400 microg bid) or placebo, and the study was continued for another 10 weeks.

RESULTS

Loss of asthma control developed in 8 of 12 patients over the 10-week period of steroid withdrawal, whereas only 1 of 10 patients with budesonide treatment had exacerbations. Those with an exacerbation had increased sputum interleukin (IL)-8 (p < 0.0001) and increased sputum neutrophil numbers (p < 0.0001) compared to those without an exacerbation. The significant elevation in sputum IL-8 and neutrophil counts initially occurred 2 weeks prior to an exacerbation. Sputum neutrophilia correlated positively with changes in IL-8 levels (r(2) = 0.76, p = 0.01).

CONCLUSIONS

Rapid withdrawal of inhaled corticosteroids results in an exacerbation of asthma that is preceded by an increase in sputum neutrophils and IL-8 concentrations, in contrast to an increase in eosinophils reported in previous studies in which inhaled steroids are slowly tapered.

Differential flow analysis of exhaled nitric oxide in patients with asthma of differing severity

BACKGROUND

The majority of asthmatic patients achieve control of their illness; others do not. It is therefore crucial to validate/develop strategies that help the clinician monitor the disease, improving the response to treatment.

METHODS

We have quantified the inflammation in central and peripheral airways by measuring exhaled nitric oxide (NO) at multiple exhalation flows in 56 asthmatics at different levels of severity (mild, n = 10; moderate stable, n = 17; moderate during exacerbation, n = 11; severe, n = 18, 7 of whom were receiving oral corticosteroids) and 18 healthy control subjects. The reproducibility of the measurement was also assessed.

RESULTS

Bronchial NO (Jno) in patients with mild asthma (2,363 +/- 330 pL/s) [mean +/- SD] was higher than in patients with moderate stable asthma (1,300 +/- 59 pL/s, p < 0.0005), in patients with severe asthma receiving inhaled corticosteroids (ICS) [1,015 +/- 67 pL/s, p < 0.0005], and healthy control subjects (721 +/- 22 pL/s, p < 0.0001). There were no differences between Jno in patients with mild asthma compared to patients with severe asthma receiving ICS and oral corticosteroids (2,225 +/- 246 pL/s). Patients with exacerbations showed a higher Jno (3,475 +/- 368.9 pL/s, p < 0.05) compared to the other groups. Alveolar NO was higher in patients with severe asthma receiving oral corticosteroids (3.0 +/- 0.1 parts per billion [ppb], p < 0.0001) than in the other groups but was not significantly higher than in patients with moderate asthma during exacerbation (2.8 +/- 0.3 ppb). No differences were seen in NO diffusion levels between the different asthma groups. All the measurements were highly reproducible and free of day-to-day and diurnal variations.

CONCLUSIONS

Differential flow analysis of exhaled NO provides additional information about the site of inflammation in asthma and may be useful in assessing the response of peripheral inflammation to therapy.

Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations

This review is the synthesis of a working group on mild asthma. Mild asthma includes intermittent and persistent mild asthma according to the Global Initiative for Asthma (GINA) classification, and affects between 50% and 75% of asthmatic patients. Mild asthma is more frequent, more symptomatic, and less well controlled in children than in adults. Cohort studies from childhood to adulthood show that asthma severity usually remains stable over time. Nevertheless, mild asthma can lead to severe exacerbations, with a frequency ranging from 0.12 to 0.77 per patient-year. Severe exacerbations in mild asthma represent 30-40% of asthma exacerbations requiring emergency consultation. In mild asthma, inflammation and structural remodelling are constant, of varying intensity, but nonspecific. Therapy with inhaled corticosteroids (ICS) decreases bronchial inflammation, but has only a slight effect on structural remodelling, and, when stopped, inflammation immediately recurs. Permanent low-dose ICS therapy is the reference treatment for persistent mild asthma. Effectiveness is to be reassessed at 3 months, and if it is insufficient the patient is no longer considered mildly asthmatic, and treatment has to be stepped up. As mild asthma is the most frequent form of the disease, diagnosis and management require physicians' particular attention.

Association of airway hyperresponsiveness with reduced quality of life in patients with moderate to severe asthma

BACKGROUND

Airway hyperresponsiveness (AHR) is an indicator of poor asthma control. Asthma patients with AHR to methacholine have been shown to have a poorer quality of life compared with asthma patients without AHR, but it is not clear to what degree this is a result of more severe disease in patients with AHR.

OBJECTIVES

To describe the relationship between AHR and quality of life in asthma patients and to determine the impact of the severity of asthma on this relationship.

METHODS

Data from 691 asthma patients were analyzed to describe the relationship between the impact of AHR to methacholine (cumulative dose of methacholine required to provoke a 20% decrease in forced expiratory volume in 1 second, < or = 8 micromol) on quality of life (measured by the Asthma Quality of Life Questionnaire) of asthma patients in relation to the severity of asthma (according to the Global Initiative for Asthma guidelines).

RESULTS

Asthma patients with AHR had more severe asthma and a poorer quality of life compared with asthma patients without AHR. Furthermore, the quality of life decreased with increasing severity of asthma. However, regression analysis showed an independent association between both the presence of AHR and the severity of asthma and quality of life, as well as an interaction between the effects of these 2 factors. Finally, subgroup analysis showed that the impact of AHR on the quality of life was only clinically significant in moderate to severe asthma but not in mild asthma.

CONCLUSIONS

AHR is associated with a negative impact on the quality of life of asthma patients that is partly independent of the severity of asthma.

Predictors of loss of asthma control induced by corticosteroid withdrawal

BACKGROUND

Asthma guidelines recommend reducing the dose of inhaled corticosteroids after establishing control.

OBJECTIVE

To identify predictors of loss of control and the kinetics of symptoms, and inflammatory and physiological measurements when inhaled corticosteroids are reduced in patients with stable asthma.

PATIENTS AND METHODS

In a single-blind study, the daily dose of inhaled corticosteroid was reduced by one-half at intervals of 20+/-2 days in 17 adults with controlled asthma until loss of asthma control occurred or until the corticosteroid was replaced with placebo for 20 days. The patients recorded symptoms and peak expiratory flow each day, and forced expiratory volume in 1 s (FEV1), the provocative concentration of methacholine causing a 20% fall in FEV1 (PC20), exhaled nitric oxide, and eosinophils in sputum and blood were measured every 10 days. A loss of asthma control was defined as a worsening of the symptoms score of at least 20%, and either a decrease in FEV1 of at least 15% or a decrease in PC20 of at least fourfold.

RESULTS

Two patients had a respiratory infection and were withdrawn from the study. In eight patients, asthma became uncontrolled after a mean of 33 days (range 13 to 48 days). This was accurately reflected by a worsening of all parameters. The first parameter to change was the sputum eosinophil percentage (20 days before the loss of asthma control). Significant changes in exhaled nitric oxide, FEV1 and methacholine PC20 were observed only when the symptoms became uncontrolled. A high blood eosinophil count at baseline (risk ratio of 2.5, 95% CI 1.0 to 6.5) and an increase in sputum eosinophil count after the reduction of corticosteroids were predictors of loss of asthma control.

CONCLUSION

In patients whose asthma is controlled on inhaled corticosteroid, it is prudent not to reduce the dose further if the blood eosinophils are increased or if the sputum eosinophils increase by as little as 1% after the reduction of corticosteroids.