Natural history of asthma: persistence versus progression-does the beginning predict the end?

Concordance of provider chart notation and guideline-based classification of asthma severity

OBJECTIVE

To evaluate concordance of asthma severity classification via physician chart notation compared with guideline-based criteria in adolescents with diagnosed asthma.

METHODS

Of 284 urban primary care and subspecialty clinic patients aged 13-18 years approached through convenience sampling, 203 surveys were completed (RR = 71.5%). We assessed concordance with sensitivity, specificity, and positive predictive values; overall agreement was evaluated with weighted kappa coefficients and McNemar's test.

RESULTS

When considering prescribed treatment according to NAEPP guidelines as a gold standard, the sensitivity for chart notation was very good for intermittent (95%) and less for non-intermittent severity ratings (51%, 58%, and 67% for moderate, severe, and mild persistent asthma, respectively). Overall agreement between chart notation and guideline-based asthma criteria ranged from fair-to-good for mild- (k = 0.36), moderate- (k = 0.44), and severe-persistent severity (k = 0.66). Although the agreement for intermittent severity was highest (k = 0.88), it did not significantly differ by between the two classifications (p ≥ 0.05).

CONCLUSIONS

Concordance for all non-intermittent asthma severity classifications varied between physician and medication-driven 2007 NAEPP guideline classifications in an ethnically diverse urban adolescent patient sample. Physicians should remain aware of the potential for this discordance and refer to the guidelines to classify and treat adolescents with asthma.

Impact of SARS-CoV-2 (COVID-19) Infections on Mental Health Diagnoses in Youth With Chronic Illness

Objective

Stressors from the COVID-19 pandemic and limited availability of mental health care services have negatively impacted youth mental health in a significant way. In the first year of the pandemic, global prevalence of anxiety and depression increased by roughly 25% in pediatric populations. While the general trend is clear, this research aimed to explore the added mental health burden of acute COVID-19 on pediatric patients with chronic conditions and describe the differences in mental health outcomes between pediatric patients with 2 common chronic conditions (asthma and diabetes) to better understand specific factors that may increase susceptibility to mental health concerns.

Method

Using the TriNetX database, data were extracted for all pediatric patients (aged 5-17 years) with a positive SARS-CoV-2 infection (COVID-19) within a 1-year time frame (April 7, 2021, to April 6, 2022). These patients were divided into 4 cohorts based on the presence of chronic conditions before COVID-19 infection: diabetes (n = 1,587), asthma (n = 13,217), diabetes plus asthma (n = 626), and neither diabetes nor asthma (n = 104,427). For all cohorts, patients with other chronic illness and previous mental health diagnoses were excluded using relevant ICD-10 codes. After matching for demographics, comorbid conditions, and body mass index, odds ratios (ORs) of the following outcomes were compared between cohorts after 6 months: new psychiatric diagnosis using relevant ICD-10 codes, hospitalization within 1 week, and mortality.

Results

After matching, there were statistically significant differences in outcomes between patients with chronic illness and healthy controls after 6 months. Compared with healthy controls, the asthma cohort OR of developing a new psychiatric diagnosis was 1.4 (95% CI 1.15-1.71, p < .001), and the diabetes cohort OR was 1.81 (95% CI 1.11-2.94, p = .015). The new psychiatric diagnosis OR of the asthma cohort compared with the diabetes cohort was 0.62 (95% CI 0.39-0.99, p = .045), suggesting that patients in the diabetes cohort were particularly susceptible to additional mental health diagnoses after an acute COVID-19 infection.

Conclusion

Compared with healthy controls, pediatric patients with asthma and pediatric patients with diabetes experienced increased odds of developing a new psychiatric diagnosis after an acute COVID-19 infection.

Investigations of a combination of atopic status and age of asthma onset identify asthma subphenotypes

OBJECTIVE

Subphenotypes of asthma may be determined by age onset and atopic status. We sought to characterize early or late onset atopic asthma with fungal or non-fungal sensitization (AAFS or AANFS) and non-atopic asthma (NAA) in children and adults in the Severe Asthma Research Program (SARP). SARP is an ongoing project involving well-phenotyped patients with mild to severe asthma.

METHODS

Phenotypic comparisons were performed using Kruskal-Wallis or chi-square test. Genetic association analyses were performed using logistic or linear regression.

RESULTS

Airway hyper-responsiveness, total serum IgE levels, and T2 biomarkers showed an increasing trend from NAA to AANFS and then to AAFS. Children and adults with early onset asthma had greater % of AAFS than adults with late onset asthma (46% and 40% vs. 32%; P < 0.00001). In children, AAFS and AANFS had lower % predicted FEV1 (86% and 91% vs. 97%) and greater % of patients with severe asthma than NAA (61% and 59% vs. 43%). In adults with early or late onset asthma, NAA had greater % of patients with severe asthma than AANFS and AAFS (61% vs. 40% and 37% or 56% vs. 44% and 49%). The G allele of rs2872507 in GSDMB had higher frequency in AAFS than AANFS and NAA (0.63 vs. 0.55 and 0.55), and associated with earlier age onset and asthma severity.

CONCLUSIONS

Early or late onset AAFS, AANFS, and NAA have shared and distinct phenotypic characteristics in children and adults. AAFS is a complex disorder involving genetic susceptibility and environmental factors.

Development of a Symptom-Based Tool for Screening of Children at High Risk of Preschool Asthma

IMPORTANCE

Despite advances in asthma therapeutics, the burden remains highest in preschool children; therefore, it is critical to identify primary care tools that distinguish preschool children at high risk for burdensome disease for further evaluation. Current asthma prediction tools, such as the modified Asthma Predictive Index (mAPI), require invasive tests, limiting their applicability in primary care and low-resource settings.

OBJECTIVE

To develop and evaluate the use of a symptom-based screening tool to detect children at high risk of asthma, persistent wheeze symptoms, and health care burden.

DESIGN, SETTING, AND PARTICIPANTS

The cohort for this diagnostic study included participants from the CHILD Study (n = 2511) from January 1, 2008, to December 31, 2012, the Raine Study from January 1, 1989, to December 31, 2012 (n = 2185), and the Canadian Asthma Primary Prevention Study (CAPPS) from January 1, 1989, to December 31, 1995 (n = 349), with active follow-up to date. Data analysis was performed from November 1, 2019, to May 31, 2022.

EXPOSURES

The CHILDhood Asthma Risk Tool (CHART) identified factors associated with asthma in patients at 3 years of age (timing and number of wheeze or cough episodes, use of asthma medications, and emergency department visits or hospitalizations for asthma or wheeze) to identify children with asthma or persistent symptoms at 5 years of age.

MAIN OUTCOMES AND MEASURES

Within the CHILD Study cohort, CHART was evaluated against specialist clinician diagnosis and the mAPI. External validation was performed in both a general population cohort (Raine Study [Australia]) and a high-risk cohort (CAPPS [Canada]). Predictive accuracy was measured by sensitivity, specificity, area under the receiver operating characteristic curve (AUROC), and positive and negative predicted values.

RESULTS

Among 2511 children (mean [SD] age at 3-year clinic visit, 3.08 [0.17] years; 1324 [52.7%] male; 1608 of 2476 [64.9%] White) with sufficient questionnaire data to apply CHART at 3 years of age, 2354 (93.7%) had available outcome data at 5 years of age. CHART applied in the CHILD Study at 3 years of age outperformed physician assessments and the mAPI in predicting persistent wheeze (AUROC, 0.94; 95% CI, 0.90-0.97), asthma diagnosis (AUROC, 0.73; 95% CI, 0.69-0.77), and health care use (emergency department visits or hospitalization for wheeze or asthma) (AUROC, 0.70; 95% CI, 0.61-0.78). CHART had a similar predictive performance for persistent wheeze in the Raine Study (N = 2185) in children at 5 years of age (AUROC, 0.82; 95% CI, 0.79-0.86) and CAPPS (N = 349) at 7 years of age (AUROC, 0.87; 95% CI, 0.80-0.94).

CONCLUSIONS AND RELEVANCE

In this diagnostic study, CHART was able to identify children at high risk of asthma at as early as 3 years of age. CHART could be easily incorporated as a routine screening tool in primary care to identify children who need monitoring, timely symptom control, and introduction of preventive therapies.

TFR1 expression in induced sputum is associated with asthma severity

Background

Asthma is characterized as a chronic inflammatory airway disease. Iron accumulation is related to asthma pathogenesis. Transferrin receptor 1(TFR1) expression is associated with intracellular iron overload in macrophages. In our study, we explored the association among TFR1 expression, the inflammatory macrophage phenotype, and asthma severity.

Methods

Induced sputum was collected from 50 asthma patients. Real-time PCR was used to evaluate mRNA expression. The status of inflammatory macrophage phenotype was assessed using flow cytometry.

Results

TFR1 levels were inversely correlated with forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) and FEV₁/vital capacity (VC). Among inflammatory cytokines, TFR1 expression was positively correlated with IL-1β, TNF-α, IL-6, IFN-γ, and IL-17A mRNA expression in induced sputum. Moreover, TFR1 expression was positively correlated with the number of proinflammatory M1 macrophages and iNOS expression in induced sputum. Neutrophil counts in induced sputum were significantly and positively related to TFR1 expression. Furthermore, TFR1 expression showed an increasing trend in asthma patients with no family history. Our findings indicated that TFR1 expression was consistent with the asthma severity index, especially the proinflammatory M1 macrophage phenotype. TFR1 expression may be a good marker to indicate asthma severity.

Prospective study of disease persistence and lung function trajectories of childhood asthma

BACKGROUND

A proportion of asthmatic children outgrow their disease by adulthood, but there are limited data on predictors for asthma persistence. This prospective study characterized the trajectory of spirometric indices and identified predictors for the persistence of childhood asthma.

METHODS

Chinese asthmatic children aged 6-15 years from pediatric allergy clinic underwent annual visits for ≥5 years and until their adulthood. Pre-bronchodilator spirometry and anti-asthma medications were recorded at baseline and then at least annually. Asthma resolution was defined when patients were free from asthma symptoms and use of anti-asthma drugs for ≥2 years. Logistic regression was used to identify predictors for asthma persistence. Generalized estimating equation was used to analyze longitudinal changes in lung function parameters in relation to asthma persistence.

RESULTS

181 asthmatic children aged [mean (SD)] 10.0 (2.7) years were followed for [mean (SD)] 12.5 (2.8) years. One third of them outgrew asthma during follow-up. Female was 3.36 times more likely to have persistent asthma. Inhaled corticosteroid (ICS) treatment ever and frequent asthma exacerbation (AE) predicted asthma persistence with respective odds ratios of 3.19 (95% confidence interval [CI] 1.44-7.09) and 3.05 (95% CI 1.39-6.68). Persistent asthma was inversely associated with baseline forced expiratory volume in 1-second (FEV₁ %) with an odds ratio of 0.96 (95% CI 0.93-1.00). Throughout follow-up, patients with persistent asthma had generally lower forced expiratory indices than those with asthma resolution. Children with persistent asthma experienced poorer lung function growth.

CONCLUSIONS

Female, ICS ever, and frequent AE predicted persistent asthma. Patients with persistent asthma had lower forced expiratory indices and poorer lung function growth into adulthood.

Residential Proximity to Biorefinery Sources of Air Pollution and Respiratory Diseases in New York State

Understanding potential health risks associated with biofuel production is critical to sustainably combating energy insecurity and climate change. However, the specific health impacts associated with biorefinery-related emissions are not yet well characterized. We evaluated the relationship between respiratory emergency department (ED) visits (2011-2015) and residential exposure to biorefineries by comparing 15 biorefinery sites to 15 control areas across New York (NY) State. We further examined these associations by biorefinery types (e.g., corn, wood, or soybean), seasons, and lower respiratory disease subtypes. We measured biorefinery exposure using residential proximity in a cross-sectional study and estimation of biorefinery emission via AERMOD-simulated modeling. After controlling for multiple confounders, we consistently found that respiratory ED visit rates among residents living within 10 km of biorefineries were significantly higher (rate ratios (RRs) range from 1.03 to 3.64) than those in control areas across our two types of exposure indices. This relationship held across biorefinery types (higher in corn and soybean biorefineries), seasons (higher in spring and winter), air pollutant types (highest for NO₂), and respiratory subtypes (highest for emphysema). Further research is needed to confirm our findings.

Small Airway Disease in Pediatric Asthma: the Who, What, When, Where, Why, and How to Remediate. A Review and Commentary

Asthma affects all portions of the airways. Small airways, however, comprise a substantial component of the conducting lung air flow. In asthma, inflammatory processes can affect the whole respiratory tract, from central to peripheral/small airways. The emphasis in adult and pediatric respiratory disease clinics is to focus on large airway obstruction and reversibility. This information, although valuable, underemphasizes a large portion of the conduction airway of asthmatics. Standard descriptions of asthma management focus on a multiple medication approaches. We particularly focused on the management of asthma in the international guidelines for the Global Initiative for Asthma (GINA). Overall, however, minimal attention is placed on the small airway pool in asthma medical management. We took the opportunity to thoroughly review and present specific data from the adult asthma literature which supported the concept that small airway abnormalities may play a role in the pathogenesis and clinical expression of asthma. Based on the conclusions of the adult asthma literature, we here present a thorough review of the literature as it relates to small airway disease in children with asthma. We used, collectively, individual data sources of data to expand the information available from standard diagnostic techniques, especially spirometry, in the evaluation of small airway disease. As the pharmacological approaches to moderate to severe asthma are advancing rapidly into the realm of biologics, we sought to present potential pharmacological options for small airway dysfunction in pediatrics prior to biological modifier intervention.

Low-Dose LPS Induces Tolerogenic Treg Skewing in Asthma

The mechanism(s) underlying endotoxin tolerance in asthma remain elusive. As the endotoxin lipopolysaccharide (LPS) affects the expression of the regulatory T-cell (Treg)-suppressive glucocorticoid-induced tumor necrosis factor receptor ligand (GITRL) on antigen-presenting dendritic cells (DCs), we hypothesized that LPS-induced changes in DC GITRL expression may impact Treg-mediated T-helper (Th) cell suppression and the induction of endotoxin tolerance. Here, we propose a novel mechanism by which low-dose LPS inhalation in neonatal mice induces endotoxin tolerance, thereby offering protection from later asthma development. Three-day old wild-type and Toll-like receptor 4 (TLR4)-deficient neonatal mice were exposed to low-dose LPS (1 μg) intranasally for 10 consecutive days prior to ovalbumin (OVA)-induced asthma to better understand the tolerogenic mechanism(s) of low-dose LPS pre-exposure. In vivo findings were validated using in vitro co-culturing studies of primary CD11c⁺ DCs and CD4⁺ T-cells with or without low-dose LPS pre-exposure before OVA stimulation. Low-dose LPS pre-exposure upregulated the Treg response and downregulated pathogenic Th2 and Th17 responses through promoting apoptosis of Th2 and Th17 cells. Low-dose LPS pre-exposure downregulated DC GITRL expression and T-cell GITR expression. Artificial DC GITRL expression abrogated the tolerogenic Treg-skewing effect of low-dose LPS pre-exposure. Low-dose LPS pre-exposure inhibited TRIF/IRF3/IFNβ signaling and upregulated expression of tolerogenic TRIF/IRF3/IFNβ negative regulators in a TLR4-dependent manner. This tolerogenic DC GITRL downregulation was attributable to TRIF/IRF3/IFNβ signaling inhibition. Low-dose LPS pre-exposure produces tolerogenic Treg skewing in neonatal asthmatic mice, a phenomenon attributable to TLR4-dependent TRIF/IRF3/IFNβ-mediated DC GITRL downregulation.

Effect of omalizumab on lung function and eosinophil levels in adolescents with moderate-to-severe allergic asthma

BACKGROUND

Omalizumab improves clinical outcomes in patients with asthma. Several studies have shown lung function improvements with omalizumab; however, this has not been examined exclusively in adolescents.

OBJECTIVE

To assess the effect of omalizumab on lung function and eosinophil counts in adolescents with uncontrolled moderate-to-severe allergic asthma.

METHODS

In this post hoc analysis, data from adolescents aged 12 to 17 years from 8 randomized trials of omalizumab were pooled (studies 008, 009, and 011, and SOLAR, INNOVATE, ALTO, ETOPA, and EXTRA). Changes from baseline to end of study in forced expiratory volume in 1 second (FEV₁), percent predicted FEV₁ (ppFEV₁), forced vital capacity (FVC), and blood eosinophil counts were assessed by fitting an analysis of covariance model and calculating least squares mean (LSM) difference for omalizumab vs placebo.

RESULTS

A total of 340 adolescents were identified (omalizumab, n = 203 [59.7%]; placebo, n = 137 [40.3%]). Omalizumab increased all baseline lung function variables more than placebo by end of study: LSM treatment differences (95% confidence interval) were 3.0% (0.2%-5.7%; P = .035), 120.9 mL (30.6-211.2 mL; P = .009), and 101.5 mL (8.3-194.6 mL; P = .033) for ppFEV₁, absolute FEV₁, and FVC, respectively. The LSM difference demonstrated a greater reduction in eosinophil counts for omalizumab vs placebo: -85.9 cells/μL (-137.1 to -34.6 cells/μL; P = .001).

CONCLUSION

Omalizumab was associated with lung function improvements and circulating eosinophil counts reductions in adolescents with moderate-to-severe uncontrolled asthma. Findings emphasize the effect of omalizumab in young patients and the need to optimize treatment early in the disease course. https://clinicaltrials.gov/: NCT00314574, NCT00046748, NCT00401596.

Children with Asthma Have Fixed Airway Obstruction through Childhood Unaffected by Exacerbations

BACKGROUND

Children with asthma may have a disease course with or without exacerbations, but the relationship between exacerbations and lung function development is poorly understood.

OBJECTIVE

To compare lung function trajectories from birth till adolescence in asthmatic children with and without exacerbations.

METHODS

Children with asthma from the Copenhagen Prospective Studies on Asthma in Childhood₂₀₀₀ (COPSAC₂₀₀₀) birth cohort had lung function and bronchial reactivity assessed repeatedly from 1 month to 13 years. Exacerbations were diagnosed at the COPSAC clinic defined as symptoms requiring hospitalization, oral or high-dose inhaled corticosteroid treatment. Mixed models were applied to analyze lung function trajectories.

RESULTS

Children with asthma with exacerbations (N = 50) had a trajectory of increased, fixed airway obstruction compared with children without exacerbations (N = 47): z-score difference in airway resistance (sRaw_z) (95% confidence interval [CI]): +0.34 (+0.03; +0.66), P = .03, and maximal mid-expiratory flow (MMEF_z): -0.41 (-0.69; -0.13), P = .004, but no differences in forced expiratory volume (FEV_z): -0.14 (-0.41; +0.13), P = .29, or bronchial reactivity to methacholine (PD_z): +0.08 (-0.26; +0.42), P = .65. This did not change comparing lung function trajectories before and after exacerbations: z-score difference (95% CI) sRaw_z: -0.04 (-0.35; 0.27), P = .80; MMEF_z: 0.01 (-0.02; 0.04), P = .55; FEV_z: 0.02 (-0.02; 0.05), P = .42; and PD_z: -0.01 (-0.06; 0.05), P = .88.

CONCLUSION

Children with asthma with exacerbations compared with children with asthma without exacerbations are characterized by increased airway obstruction since infancy through childhood. The airway obstruction is a fixed trajectory without progression due to exacerbations, suggesting that exacerbations are a consequence rather than a cause of diminished airway caliber in childhood.

Can early intervention in pediatric asthma improve long-term outcomes? A question that needs an answer

OBJECTIVE

Although many children with asthma do not experience persistence into adulthood, recent studies have suggested that poorly controlled asthma in childhood may be associated with significant airflow obstruction in adulthood. However, data regarding disease progression are lacking, and clinicians are not yet able to predict the course of a child's asthma. The goal of this article was to assess the current understanding of childhood asthma treatment and progression and to highlight gaps in information that remain.

DATA SOURCES

Nonsystematic PubMed literature search and authors' expertise.

STUDY SELECTION

Articles were selected at the authors' discretion based on areas of interest in childhood asthma treatment and progression into adulthood.

RESULTS

Uncontrolled asthma in early childhood can potentially have lasting effects on lung development, but it is unclear whether traditional interventions in very young children preserve lung function. Although not all children respond to standard interventions, certain asthma phenotypes have been identified that can help to understand which children may respond to a particular treatment.

CONCLUSION

Clinicians should monitor children's asthma control and pulmonary function over time to assess the long-term impact of an intervention and to minimize the effect of uncontrolled asthma, especially exacerbations, on lung development. New biologic therapies have shown promise in treating adults with severe, uncontrolled asthma, and some of these therapies are approved in the United States for children as young as age 6. However, knowledge gaps regarding the efficacy and safety of these treatments in younger children hamper our understanding of their effect on long-term outcomes.

Hyperresponsiveness: Relating the Intact Airway to the Whole Lung

We relate changes of the airway wall to the response of the intact airway and the whole lung. We address how mechanical conditions and specific structural changes for an airway contribute to hyperresponsiveness resistant to deep inspiration. This review conveys that the origins of hyperresponsiveness do not devolve into an abnormality at single structural level but require examination of the complex interplay of all the parts.

Long-Term Trajectories of Mild Asthma in Adulthood and Risk Factors of Progression

BACKGROUND

Most patients with asthma have mild disease. However, the clinical course of mild asthma and risk factors for progression are not well studied.

OBJECTIVE

To examine the long-term trajectories of mild asthma and the effects of early-stage risk factors on the subsequent disease course.

METHODS

From the administrative health data of British Columbia, Canada, we identified patients aged 14 to 45 years with newly diagnosed mild asthma between January 1997 and December 2012. For each follow-up year, we categorized a patient's asthma severity into mild/dormant, moderate, or severe on the basis of the intensity of asthma medications and occurrence of exacerbations. Ordinal logistic regression was used to estimate the probability of severity or all-cause death in the next year as a function of a patient's severity history in the past 3 years and selected baseline risk factors.

RESULTS

The study included 70,829 patients with incident mild asthma (62% women; mean age, 31 years). Over 10 years, 8% of these patients transitioned to moderate or severe asthma. Inappropriate use of rescue medications and older age were the most influential determinants for progression from mild asthma (odds ratios, 1.79; 95% CI, 1.68-1.90; P < .001; 1.24 per 10-year increase in age; 95% CI, 1.22-1.27; P < .001), whereas the presence of allergic rhinitis had no significant effects (odds ratio, 0.95; 95% CI, 0.91-1.00; P = .063).

CONCLUSIONS

Mild asthma remains largely stable over time. However, potentially modifiable factors such as inappropriate use of rescue medications are associated with a worsened prognosis.

The Role of Oxidative Stress in the Clinical Manifestations of Childhood Asthma

INTRODUCTION

The significance of oxidative stress in pathogenesis of childhood asthma was recognized, but its role in the clinical manifestations of disease is still unclear.

MATERIALS AND METHODS

The study was conducted in 96 asthmatic children. The urinary biomarker of oxidative stress, 8-oxo-7,8-dihydro-2-deoxyguanosine (8-oxodG/creatinine) was determined by using HPLC-MS/MS. ELISA was performed to measure myeloperoxidase (MPO) and Cu,Zn- superoxide dismutase (Cu,Zn-SOD) in serum.

RESULTS

Logistic regression analysis revealed that female gender, tobacco smoke exposure, and increased 8-oxodG/creatinine were associated with risk for intermittent asthma, while the positive allergy test and increased Cu,Zn-SOD were associated with eczema in asthmatic children. Higher MPO (p = 0.033), and percent of granulocytes (p = 0.030) were found in severe persistent asthma in comparison to intermittent or mild persistent asthma.

CONCLUSION

The main findings that TSE-induced oxidative stress is a risk for intermittent asthma and eczema may be clinically significant for the disease prevention and therapeutic improvements.

An Official American Thoracic Society Research Statement: Current Challenges Facing Research and Therapeutic Advances in Airway Remodeling

BACKGROUND

Airway remodeling (AR) is a prominent feature of asthma and other obstructive lung diseases that is minimally affected by current treatments. The goals of this Official American Thoracic Society (ATS) Research Statement are to discuss the scientific, technological, economic, and regulatory issues that deter progress of AR research and development of therapeutics targeting AR and to propose approaches and solutions to these specific problems. This Statement is not intended to provide clinical practice recommendations on any disease in which AR is observed and/or plays a role.

METHODS

An international multidisciplinary group from within academia, industry, and the National Institutes of Health, with expertise in multimodal approaches to the study of airway structure and function, pulmonary research and clinical practice in obstructive lung disease, and drug discovery platforms was invited to participate in one internet-based and one face-to-face meeting to address the above-stated goals. Although the majority of the analysis related to AR was in asthma, AR in other diseases was also discussed and considered in the recommendations. A literature search of PubMed was performed to support conclusions. The search was not a systematic review of the evidence.

RESULTS

Multiple conceptual, logistical, economic, and regulatory deterrents were identified that limit the performance of AR research and impede accelerated, intensive development of AR-focused therapeutics. Complementary solutions that leverage expertise of academia and industry were proposed to address them.

CONCLUSIONS

To date, numerous factors related to the intrinsic difficulty in performing AR research, and economic forces that are disincentives for the pursuit of AR treatments, have thwarted the ability to understand AR pathology and mechanisms and to address it clinically. This ATS Research Statement identifies potential solutions for each of these factors and emphasizes the importance of educating the global research community as to the extent of the problem as a critical first step in developing effective strategies for: (1) increasing the extent and impact of AR research and (2) developing, testing, and ultimately improving drugs targeting AR.

Functional Effects of WNT1-Inducible Signaling Pathway Protein-1 on Bronchial Smooth Muscle Cell Migration and Proliferation in OVA-Induced Airway Remodeling

Upregulation of WISP1 has been demonstrated in lung remodeling. Moreover, it has been recently found that some signaling components of WNT pathway can activate GSK3β signaling to mediate remodeling of airway smooth muscle (ASM) in asthma. Therefore, we hypothesized that WISP1, a signaling molecule downstream of the WNT signaling pathway, is involved in PI3K/GSK3β signaling to mediate ASM remodeling in asthma. Our results showed that WISP1 depletion partly suppressed OVA-induced ASM hypertrophy in vivo. In vitro, WISP1 could induce hBSMC hypertrophy and proliferation, accompanied by upregulation of levels of PI3K, p-Akt, p-GSK3β, and its own expression. TGF-β treatment could increase expression of PI3K, p-Akt, p-GSK3β, and WISP1. SH-5 treatment could partly suppress TGF-β-induced hypertrophy and proliferation of hBSMC, and depress expression of p-GSK3β and WISP1. In conclusion, WISP1 may be a potential inducer of ASM proliferation and hypertrophy in asthma. The pro-remodeling effect of WISP1 is likely due to be involved in PI3K-GSK3β-dependent noncanonical TGF-β signaling.

Predicting asthma outcomes

This review addresses predictors of remission or persistence of wheezing and asthma from early childhood through adulthood. Early childhood wheezing is common, but predicting who will remit or have persistent childhood asthma remains difficult. By adding parental history of asthma and selected infant biomarkers to the history of recurrent wheezing, the Asthma Predictive Index and its subsequent modifications provide better predictions of persistence than simply the observation of recurrent wheeze. Sensitization, especially to multiple allergens, increases the likelihood of development of classic childhood asthma. Remission is more likely in male subjects and those with milder disease (less frequent and less severe symptoms), less atopic sensitization, a lesser degree of airway hyperresponsiveness, and no concomitant allergic disease. Conversely, persistence is linked strongly to allergic sensitization, greater frequency and severity of symptoms, abnormal lung function, and a greater degree of airway hyperresponsiveness. A genetic risk score might predict persistence more accurately than family history. Remission of established adult asthma is substantially less common than remission during childhood and adolescence. Loss of lung function can begin early in life and tracks through childhood and adolescence. Despite therapy which controls symptoms and exacerbations, the outcomes of asthma appear largely resistant to pharmacologic therapy.

Pharmacodynamic and pharmacokinetic evaluation of house dust mite sublingually administered immunotherapy tablet in the treatment of asthma

INTRODUCTION

Sublingual immunotherapy (SLIT) for house dust mite (HDM) allergy has an evidence of efficacy demonstrated by meta-analyses, but marked differences are reported between the various SLIT products. The standardized quality (SQ) HDM sublingual tablet containing Dermatophagoides pteronyssinus and Dermatophagoides farinae in a 1:1 ratio (MK-8237) is a qualitative advance for SLIT products.

AREAS COVERED

The rationale for developing the HDM tablets is discussed against the other available SLIT products, analyzing the clinical data on efficacy and safety obtained by controlled trials.

EXPERT OPINION

Following preliminary Phase I and II studies, a double-blind, placebo-controlled trial on 604 patients with mite-induced asthma, aged more than 14 years and treated by inhaled budesonide, was performed using one of three active doses (1, 3 or 6 SQ) or placebo. The results showed a significant mean difference between 6 SQ-HDM and placebo in the reduction in daily budesonide dose of 81 µg (p = 0.004), with relative mean and median reductions of 42 and 50% for 6 SQ-HDM and 15 and 25% for placebo, respectively. Safety was very good, with no report of anaphylactic reaction. These findings suggest a role to the HDM SLIT tablets in the treatment of patients with mite-induced asthma.

Inhaled house dust programs pulmonary dendritic cells to promote type 2 T-cell responses by an indirect mechanism

The induction of allergen-specific T helper 2 (Th2) cells by lung dendritic cells (DCs) is a critical step in allergic asthma development. Airway delivery of purified allergens or microbial products can promote Th2 priming by lung DCs, but how environmentally relevant quantities and combinations of these factors affect lung DC function is unclear. Here, we investigated the ability of house dust extract (HDE), which contains a mixture of environmental adjuvants, to prime Th2 responses against an innocuous inhaled antigen. Inhalational exposure to HDE conditioned lung conventional DCs, but not monocyte-derived DCs, to induce antigen-specific Th2 differentiation. Conditioning of DCs by HDE was independent of Toll-like receptor 4 signaling, indicating that environmental endotoxin is dispensable for programming DCs to induce Th2 responses. DCs directly treated with HDE underwent maturation but were poor stimulators of Th2 differentiation. In contrast, DCs treated with bronchoalveolar lavage fluid (BALF) from HDE-exposed mice induced robust Th2 differentiation. DC conditioning by BALF was independent of the proallergic cytokines IL-25, IL-33, and thymic stromal lymphopoietin. BALF treatment of DCs resulted in upregulation of CD80 but low expression of CD40, CD86, and IL-12p40, which was associated with Th2 induction. These findings support a model whereby environmental adjuvants in house dust indirectly program DCs to prime Th2 responses by triggering the release of endogenous soluble factor(s) by airway cells. Identifying these factors could lead to novel therapeutic targets for allergic asthma.

Asthma, COPD and overlap syndrome: a longitudinal study in young European adults

We compared risk factors and clinical characteristics, 9-year lung function change and hospitalisation risk across subjects with the asthma-chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS), asthma or COPD alone, or none of these diseases.Participants in the European Community Respiratory Health Survey in 1991-1993 (aged 20-44 years) and 1999-2001 were included. Chronic airflow obstruction was defined as pre-bronchodilator forced expiratory volume in 1 s (FEV1)/forced vital capacity<lower limit of normal on both occasions. Based on their history of respiratory symptoms, spirometry and risk factors, subjects were classified as having asthma alone (n=941), COPD alone (n=166), ACOS (n=218) and none of these (n=5659).Subjects with ACOS shared risk factors and clinical characteristics with subjects with asthma alone, but they had an earlier age of asthma onset. FEV1 change in the ACOS group (-25.9 mL·year(-1)) was similar to that in the asthma group (-25.3 mL·year(-1)), and lower (p<0.001) than in the COPD group (-37.3 mL·year(-1)). ACOS was associated with the highest hospitalisation rate.Among young adults aged 20-44 years, ACOS seems to represent a form of severe asthma, characterised by more frequent hospitalisations, and to be the result of early-onset asthma that has progressed to fixed airflow obstruction.

Indoor environmental factors associated with wheezing illness and asthma in South Korean children: phase III of the International Study of Asthma and Allergies in Childhood

BACKGROUND

The relationship between exposure to indoor environmental pollutants and incidence of asthma and wheezing illness in children is unclear. This study aimed to clarify this relationship by identifying the risk factors associated with these conditions in South Korean children aged 6-7 years.

METHODS

The parents or guardians of 3810 children aged 6-7 years who had participated in the International Study of Asthma and Allergies in Childhood and met the study criteria completed validated questionnaires regarding their children's asthma and wheezing illness, risk factors and exposure to indoor pollutants. The data were subjected to chi-square and multivariate logistic regression analysis to identify the factors significantly associated with asthma and wheezing illness.

RESULTS

Parental history of allergic disease (odds ratio [OR]: 1.729; 95% confidence interval [CI]: 1.447-2.066), living on the basement or semi-basement floor (OR: 1.891; 95% CI: 1.194-2.996) and living in housing that had been remodeled within the last 12 months (OR: 1.376; 95% CI: 1.101-1.720) were found to be significantly associated with wheezing illness. Parental history of allergic disease (OR: 2.189; 95% CI: 1.483-3.231), male sex (OR: 1.971; 95% CI: 1.369-2.838) and positive skin prick test (SPT) result (OR: 1.583; 95% CI: 1.804-3.698) were found to be significantly associated with current asthma.

CONCLUSIONS

Although the risk factors for current asthma appear to be more related to the non-modifiable risk factors like sex, parental history of allergic diseases, SPT, the two groups are associated with exposure to modifiable indoor environmental factors.

Development of rhinitis may be an indicator for the persistence of childhood asthma

OBJECTIVES

Results of previous studies have established several factors related with the natural course of childhood asthma. The aim of this study is to investigate the prognosis of childhood asthma and to determine possible risk factors for disease persistence.

METHODS

An outpatient cohort with a median (interquartile range) follow-up duration of 19.4 (17.7-21.8) years was re-evaluated. Current clinical remission (CR) was defined as no asthma symptoms and no use of controller medication within the past year.

RESULTS

Out of 115 patients, 78 could be surveyed with questionnaire and 46 patients with a median age of 25.3 (23.9-27.0) years were further investigated with clinical work-up. Nineteen (24.4%) patients were in CR in both visits (adolescence and young adulthood). A further 7 patients (9.0%) who were not in CR at adolescence were in CR at the young adulthood visit. However, 21 patients (26.9%) who were in CR at adolescence were not in CR at the young adulthood visit. Thirty-one patients (39.7%) with persistent symptoms at adolescence were not in CR at young adulthood, either. In multivariate logistic models, the presence of obstructive pattern (forced expiratory volume in 1s (FEV1)/forced vital capacity (FVC) <80% vs. ≥80%) in pulmonary function tests during the adolescence period (odds ratio; [95% confidence interval] (6.71 [1.65-27.29]; p=0.008) and later-onset rhinitis (10.27 [1.18-89.13]; p=0.035) predicted the absence of CR at young adulthood.

CONCLUSION

A substantial number of patients who were in CR during adolescence have re-emerging disease. The presence of obstructive pattern in adolescence and later-onset rhinitis were associated with the absence of CR in young adults with asthma. Awareness of risk factors along with early interventions may provide better results in childhood asthma.

The potential to predict the course of childhood asthma

Many children experience pre-school or early childhood wheezing. In a significant proportion symptoms disappear as the child grows, but others have persistent and troublesome asthma which can be life-long. Tools to predict course of disease in young children are a priority for families and clinicians. This review summarizes evidence from several longitudinal population-based birth-cohort studies that have identified risk factors for persistence and remission of childhood asthma. These factors include clinical characteristics, environmental and other exposures, familial factors, biomarkers of allergic inflammation, measurements of lung function and airway responsiveness, and genetic variants. This review also introduces the concept of polygenic risk and genetic risk scores, and describes results from a recent study that suggests promise for the use of genetic information in predicting the course of childhood asthma. We conclude with a discussion of implications and future directions.

Ten-year follow-up of cluster-based asthma phenotypes in adults. A pooled analysis of three cohorts

RATIONALE

The temporal stability of adult asthma phenotypes identified using clustering methods has never been addressed. Longitudinal cluster-based methods may provide novel insights in the study of the natural history of asthma.

OBJECTIVES

To compare the stability of cluster-based asthma phenotype structures a decade apart in adults and to address the individuals' phenotypic transition across these asthma phenotypes.

METHODS

The latent transition analysis was applied on longitudinal data (twice, 10 yr apart) from 3,320 adults with asthma who took part in the European Community Respiratory Health Survey, the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults, or the Epidemiological Study on Genetics and Environment of Asthma. Nine variables covering personal and phenotypic characteristics measured twice, 10 years apart, were simultaneously considered.

MEASUREMENTS AND MAIN RESULTS

Latent transition analysis identifies seven asthma phenotypes (prevalence range, 8.4-20.8%), mainly characterized by the level of asthma symptoms (low, moderate, high), the allergic status, and pulmonary function. Phenotypes observed 10 years apart showed strong similarities. The probability of membership in the same asthma phenotype at both times varied across phenotypes from 54 to 88%. Different transition patterns were observed across phenotypes. Transitions toward increased asthma symptoms were more frequently observed among nonallergic phenotypes as compared with allergic phenotypes. Results showed a strong stability of the allergic status over time.

CONCLUSIONS

Adult asthma phenotypes identified by a clustering approach, 10 years apart, were highly consistent. This study is the first to model the probabilities of transitioning over time between comprehensive asthma phenotypes.

Prevalence of childhood asthma, rhinitis, and eczema in the Ternopil region of Ukraine--results of BUPAS study

PURPOSE

The aim of the study was to estimate the prevalence of allergic diseases and symptoms in children of the Ternopil Region (Ukraine) and to explore their familial and environmental correlates.

MATERIAL/METHODS

A cross-sectional study based on parental answers to a respiratory questionnaire based on ISAAC that included 4871 urban and rural children aged 6-14 years. Association of physician-made diagnoses and symptoms with environmental factors was examined by means of multivariate logistic regression.

RESULTS

Increased risk of asthma (1.7%) was associated with urban residence (OR=1.8; p=0.04) and high parental education (OR=1.8; p= 0.02); spastic bronchitis (6.2%) with parental allergy (OR=1.3; p= 0.03); atopic eczema (6.2%) with younger age (OR=1.3; p=0.03), high parental education (OR=1.3; p=0.03), parental allergy (OR=1.4; p=0.02), tobacco smoke at home (OR=0.7; p=0.01) and household density (OR=0.6; p=0.001); diagnosis of unspecified allergic sensitization (11.8%) was related to high parental education (OR=1.2; p=0.03), parental employment (OR=0.8; p=0.02) and pets at home (OR=1.2; p=0.06). Symptoms of chest wheezing (11.5%) were related to tobacco smoke at home (OR=0.8; p=0.06). Attacks of dyspnea (7.3%) were related to parental allergy (OR=1.4; p=0.007), and type of heating (OR=1.7; p=0.04). Hay fever symptoms (5.7%) were related to younger age (OR=1.3; p=0,01) and urban residence (OR=2.0; p<0.0001).

CONCLUSIONS

Except for asthma the prevalence of allergic diseases and symptoms as well as their correlates in children of Ternopil are similar to other estimates obtained in Eastern Europe. Low prevalence of asthma and relatively frequent occurrence of spastic bronchitis may suggest substantial underdiagnosis of childhood asthma.

Short-term risk of hospitalization for asthma or bronchiolitis in children living near an aluminum smelter

Few studies have measured the effect of short-term exposure to industrial emissions on the respiratory health of children. Here we estimate the risk of hospitalization for asthma and bronchiolitis in young children associated with their recent exposure to emissions from an aluminum smelter. We used a case-crossover design to assess the risk of hospitalization, February 1999-December 2008, in relation to short-term variation in levels of exposure among children 0-4 years old living less than 7.5 km from the smelter. The percentage of hours per day that the residence of a hospitalized child was in the shadow of winds crossing the smelter was used to estimate the effect of wind-borne emissions on case and crossover days. Community-wide pollutant exposure was estimated through daily mean and daily maximum SO2 and PM2.5 concentrations measured at a fixed monitoring site near the smelter. Odds ratios (OR) were estimated using conditional logistic regressions. The risk of same-day hospitalization for asthma or bronchiolitis increased with the percentage of hours in a day that a child's residence was downwind of the smelter. For children aged 2-4 years, the OR was 1.27 (95% CI=1.03-1.56; n=103 hospitalizations), for an interquartile range (IQR) of 21% of hours being downwind. In this age group, the OR with PM2.5 daily mean levels was slightly smaller than with the hours downwind (OR: 1.22 for an IQR of 15.7 μg/m(3), 95% CI=1.03-1.44; n=94 hospitalizations). Trends were observed between hospitalizations and levels of SO2 for children 2-4 years old. Increasing short-term exposure to emissions from a Quebec aluminum smelter was associated with an increased risk of hospitalization for asthma and bronchiolitis in young children who live nearby. Estimating exposure through records of wind direction allows for the integration of exposure to all pollutants carried from the smelter stack.

Cross-roads in the lung: immune cells and tissue interactions as determinants of allergic asthma

Allergic asthma is a chronic disease of the lung characterized by underlying Th2- and IgE-mediated inflammation, structural alterations of the bronchial wall, and airway hyperresponsiveness. Initial allergic sensitization and later development of chronic disease are determined by close interactions between lung structural cells and the resident and migratory immune cells in the lung. Epithelial cells play a crucial role in allergic sensitization by directly influencing dendritic cells induction of tolerant or effector T cells and production of type 2 cytokines by innate immune cells. During chronic disease, the bronchial epithelium, stroma, and smooth muscle become structurally and functionally altered, contributing to the perpetuation of tissue remodeling. Thus, targeting tissue-driven pathology in addition to inflammation may increase the effectiveness of asthma treatment.

In vitro and in vivo pharmacological profile of PL-3994, a novel cyclic peptide (Hept-cyclo(Cys-His-Phe-d-Ala-Gly-Arg-d-Nle-Asp-Arg-Ile-Ser-Cys)-Tyr-[Arg mimetic]-NH(2)) natriuretic peptide receptor-A agonist that is resistant to neutral endopeptidase and acts as a bronchodilator

The pharmacological and airways relaxant profiles of PL-3994 (Hept-cyclo(Cys-His-Phe-d-Ala-Gly-Arg-d-Nle-Asp-Arg-Ile-Ser-Cys)-Tyr-[Arg mimetic]-NH(2)), a novel natriuretic peptide receptor-A (NPR-A) agonist, were evaluated. PL-3994, a full agonist, has high affinity for recombinant human (h), dog, or rat NPR-As (K(i)s of 1, 41, and 10 nm, respectively), and produced concentration-dependent cGMP generation in human, dog and rat NPR-As (respective EC(50)s of 2, 3 and 14 nm). PL-3994 has a K(i) of 7 nm for hNPR-C but was without effect on cGMP generation in hNPR-B. PL-3994 (1 μm) was without significant effect against 75 diverse molecular targets. PL-3994 or BNP, a natural NPR ligand, produced concentration-dependent relaxation of pre-contracted guinea-pig trachea (IC(50)s of 42.7 and 10.7 nm, respectively). PL-3994, and also BNP, (0.1 nm-100 μm) elicited a potent, concentration-dependent but small relaxation of pre-contracted human precision-cut lung slices (hPCLS). Intratracheal PL-3994 (1-1000 μg/kg) produced a dose-dependent inhibition of the bronchoconstrictor response evoked by aerosolized methacholine, but was without significant effect on cardiovascular parameters. PL-3994 was resistant to degradation by human neutral endopeptidase (hNEP) (92% remaining after 2 h), whereas the natural ligands, ANP and CNP, were rapidly metabolized (≤1% remaining after 2 h). PL-3994 is a potent, selective NPR agonist, resistant to NEP, with relaxant effects in guinea-pig and human airway smooth muscle systems. PL-3994 has the profile predictive of longer clinical bronchodilator activity than observed previously with ANP, and suggests its potential utility in the treatment of asthma, in addition to being a useful research tool to evaluate NPR biology.

Semistructured black-box prediction: proposed approach for asthma admissions in London

Asthma is a global public health problem and the most common chronic disease among children. The factors associated with the condition are diverse, and environmental factors appear to be the leading cause of asthma exacerbation and its worsening disease burden. However, it remains unknown how changes in the environment affect asthma over time, and how temporal or environmental factors predict asthma events. The methodologies for forecasting asthma and other similar chronic conditions are not comprehensively documented anywhere to account for semistructured noncausal forecasting approaches. This paper highlights and discusses practical issues associated with asthma and the environment, and suggests possible approaches for developing decision-making tools in the form of semistructured black-box models, which is relatively new for asthma. Two statistical methods which can potentially be used in predictive modeling and health forecasting for both anticipated and peak events are suggested. Importantly, this paper attempts to bridge the areas of epidemiology, environmental medicine and exposure risks, and health services provision. The ideas discussed herein will support the development and implementation of early warning systems for chronic respiratory conditions in large populations, and ultimately lead to better decision-making tools for improving health service delivery.

An RGS4-mediated phenotypic switch of bronchial smooth muscle cells promotes fixed airway obstruction in asthma

In severe asthma, bronchodilator- and steroid-insensitive airflow obstruction develops through unknown mechanisms characterized by increased lung airway smooth muscle (ASM) mass and stiffness. We explored the role of a Regulator of G-protein Signaling protein (RGS4) in the ASM hyperplasia and reduced contractile capacity characteristic of advanced asthma. Using immunocytochemical staining, ASM expression of RGS4 was determined in endobronchial biopsies from healthy subjects and those from subjects with mild, moderate and severe asthma. Cell proliferation assays, agonist-induced calcium mobilization and bronchoconstriction were determined in cultured human ASM cells and in human precision cut lung slices. Using gain- and loss-of-function approaches, the precise role of RGS proteins was determined in stimulating human ASM proliferation and inhibiting bronchoconstriction. RGS4 expression was restricted to a subpopulation of ASM and was specifically upregulated by mitogens, which induced a hyperproliferative and hypocontractile ASM phenotype similar to that observed in recalcitrant asthma. RGS4 expression was markedly increased in bronchial smooth muscle of patients with severe asthma, and expression correlated significantly with reduced pulmonary function. Whereas RGS4 inhibited G protein-coupled receptor (GPCR)-mediated bronchoconstriction, unexpectedly RGS4 was required for PDGF-induced proliferation and sustained activation of PI3K, a mitogenic signaling molecule that regulates ASM proliferation. These studies indicate that increased RGS4 expression promotes a phenotypic switch of ASM, evoking irreversible airway obstruction in subjects with severe asthma.

Asthma and the achievement gap among urban minority youth

OBJECTIVES

To outline the prevalence and disparities of asthma among school-aged urban minority youth, causal pathways through which poorly controlled asthma adversely affects academic achievement, and proven or promising approaches for schools to address these problems.

METHODS

Literature review.

RESULTS

Asthma is the most common chronic disease affecting youth in the United States; almost 10 million youth under 18 (14%) have received a diagnosis and 6.8 million (9%) have active asthma. Average annual prevalence estimates were approximately 45% higher for Black versus White children (12.8% vs. 8.8%), as were average annual estimates of asthma attacks (8.4% vs. 5.8%). Urban minority youth have highly elevated prevalence of poorly controlled asthma as evidenced by overuse of emergency departments and under-use of efficacious medications. Poorly controlled asthma has functional consequences on cognition, connectedness with school, and absenteeism. Exemplary asthma programs include management and support systems, school health and mental health services, asthma education, healthy school environments, physical education and activity, and coordination of school, family, and community efforts.

CONCLUSIONS

Asthma and, more importantly, poorly controlled asthma are highly and disproportionately prevalent among school-aged urban minority youth, has a negative impact on academic achievement through its effects on cognition, school connectedness, and absenteeism, and effective practices are available for schools to address this problem. To reduce the adverse effects of poorly controlled asthma on learning, a multifaceted approach to asthma control and prevention in which schools can and must play a central role is essential.

Attenuated expression of tenascin-C in ovalbumin-challenged STAT4-/- mice

Background

Asthma leads to structural changes in the airways, including the modification of extracellular matrix proteins such as tenascin-C. The role of tenascin-C is unclear, but it might act as an early initiator of airway wall remodelling, as its expression is increased in the mouse and human airways during allergic inflammation. In this study, we examined whether Th1 or Th2 cells are important regulators of tenascin-C in experimental allergic asthma utilizing mice with impaired Th1 (STAT4-/-) or Th2 (STAT6-/-) immunity.

Methods

Balb/c wildtype (WT), STAT4-/- and STAT6-/- mice were sensitized with intraperitoneally injected ovalbumin (OVA) followed by OVA or PBS airway challenge. Airway hyperreactivity (AHR) was measured and samples were collected. Real time PCR and immunohistochemistry were used to study cytokines and differences in the expression of tenascin-C. Tenascin-C expression was measured in human fibroblasts after treatment with TNF-α and IFN-γ in vitro.

Results

OVA-challenged WT mice showed allergic inflammation and AHR in the airways along with increased expression of TNF-α, IFN-γ, IL-4 and tenascin-C in the lungs. OVA-challenged STAT4-/- mice exhibited elevated AHR and pulmonary eosinophilia. The mRNA expression of TNF-α and IFN-γ was low, but the expression of IL-4 was significantly elevated in these mice. OVA-challenged STAT6-/- mice had neither AHR nor pulmonary eosinophilia, but had increased expression of mRNA for TNF-α, IFN-γ and IL-4. The expression of tenascin-C in the lungs of OVA-challenged STAT4-/- mice was weaker than in those of OVA-challenged WT and STAT6-/- mice suggesting that TNF-α and IFN-γ may regulate tenascin-C expression in vivo. The stimulation of human fibroblasts with TNF-α and IFN-γ induced the expression of tenascin-C confirming our in vivo findings.

Conclusions

Expression of tenascin-C is significantly attenuated in the airways of STAT4-/- mice, which may be due to the impaired secretion of TNF-α and IFN-γ in these mice.

Allergic rhinitis as a predictor for wheezing onset in school-aged children

BACKGROUND

Rhinitis in older children and adults has been shown to be a predictor for adolescent- and adult-onset asthma. These findings suggest an interaction between the upper and lower airways. Whether rhinitis is a predictor for childhood-onset asthma is unknown.

OBJECTIVE

We sought to investigate whether rhinitis in early childhood is an independent predictor for wheezing between the ages of 5 and 13 years in the German Multicentre Allergy Study birth cohort.

METHODS

The German Multicentre Allergy Study cohort initially included 1314 healthy children. They were followed from birth to the age of 13 years with regular questionnaires and interviews. Specific IgE levels were measured at yearly intervals. Airway hyperresponsiveness was assessed at 7 years.

RESULTS

Allergic rhinitis until the age of 5 years was found to be a predictor for developing wheezing between the ages of 5 and 13 years, with an adjusted relative risk of 3.82 (P < .001). This association was not attributable to the type of sensitization, the severity of sensitization, or atopic dermatitis during the first 2 years of life. In this group of children, 41.5% of all new cases of wheezing occurred among children with preceding allergic rhinitis.

CONCLUSIONS

The first manifestation of allergic rhinitis occurs in preschool children in whom it is a predictor for subsequent wheezing onset. Preschool children with rhinitis might thus benefit from early assessment of allergic sensitization to identify the children at high risk of wheezing.

Prognostic bases of asthma. Natural history?

Different causes of asthma have been established. The most common cause is conditioned to a genetic predisposition towards atopy (atopic asthma), although other factors can also give rise to bronchial inflammation, such as over-exposure to environmental irritants (occupational asthma), altered arachidonic acid metabolism (aspirin-induced asthma) and also exercise - in which different thermal and osmotic mechanisms are known to intervene. The prognosis of these different variants of asthma depends on the severity of the condition; patient age at onset of the disease; patient age at the time of diagnosis; the treatment provided; and adherence to therapy. The concept of "natural history" refers to the spontaneous evolution or course of the disease process in the absence of pathogenic or etiological treatment, with the provision of only symptomatic treatment. In order to gain increased certainty regarding the course of these patients, the study groups must present similar baseline characteristics in terms of the start and severity of the condition; the start of treatment; compliance; and the clinical and functional control findings.

Changes in the prevalence of childhood asthma in seoul from 1995 to 2008 and its risk factors

Purpose

To investigate the prevalence of asthma and determine its risk factors in elementary school students in Seoul.

Methods

A modified International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to survey 4,731 elementary school students from five areas in Seoul between April and October, 2008.

Results

In elementary school children, the lifetime and recent 12-month prevalence of wheezing were 11.7% and 5.6%, respectively. The lifetime prevalence of asthma diagnosis was 7.9%, and the recent 12-month prevalence of asthma treatment was 2.7%. Male sex (adjusted odds ratio [aOR], 1.90; 95% confidence interval [CI], 1.36-2.66), history of atopic dermatitis (AD) (aOR, 2.76; 95% CI, 1.98-3.84), history of allergic rhinitis (AR) (aOR, 3.71; 95% CI, 2.61-5.26), history of bronchiolitis before 2 years of age (aOR, 2.06; 95% CI, 1.39-3.07), use of antibiotics during infancy for >3 days (aOR, 1.88; 95% CI, 1.35-2.62), parental history of asthma (aOR, 2.83; 95% CI, 1.52-5.27), exposure to household molds during infancy (aOR, 1.84; 95% CI, 1.18-2.89), and the development or aggravation of asthma symptoms within 6 months after moving to a new house (aOR, 11.76; 95% CI, 5.35-25.86) were the independent risk factors for wheezing within 12 months.

Conclusions

The prevalence of wheezing and asthma in elementary school students in 2008 was similar to that in the past decade. Male sex, history of AD, history of AR, history of bronchiolitis before 2 years of age, parental asthma, use of antibiotics during infancy, exposure to molds in the house during infancy, and development or aggravation of asthma symptoms within 6 months after moving to a new house, could be risk factors for wheezing within 12 months.

Social stress and asthma: the role of corticosteroid insensitivity

Psychosocial stress alters susceptibility to infectious and systemic illnesses and may enhance airway inflammation in asthma by modulating immune cell function through neural and hormonal pathways. Stress activates the hypothalamic-pituitary-adrenal axis. Release of endogenous glucocorticoids, as a consequence, may play a prominent role in altering the airway immune homeostasis. Despite substantial corticosteroid and catecholamine plasma levels, chronic psychosocial stress evokes asthma exacerbations. Animal studies suggest that social stress induces corticosteroid insensitivity that in part may be a result of impaired glucocorticoid receptor expression and/or function. Such mechanisms likely promote and amplify airway inflammation in response to infections, allergen, or irritant exposure. This review discusses evidence of an altered corticosteroid responsive state as a consequence of chronic psychosocial stress. Elucidation of the mechanisms of stress-induced impairment of glucocorticoid responsiveness and immune homeostasis may identify novel therapeutic targets that could improve asthma management.

A new look at the pathogenesis of asthma

Asthma is an inflammatory disorder of the conducting airways that has strong association with allergic sensitization. The disease is characterized by a polarized Th-2 (T-helper-2)-type T-cell response, but in general targeting this component of the disease with selective therapies has been disappointing and most therapy still relies on bronchodilators and corticosteroids rather than treating underlying disease mechanisms. With the disappointing outcomes of targeting individual Th-2 cytokines or manipulating T-cells, the time has come to re-evaluate the direction of research in this disease. A case is made that asthma has its origins in the airways themselves involving defective structural and functional behaviour of the epithelium in relation to environmental insults. Specifically, a defect in barrier function and an impaired innate immune response to viral infection may provide the substrate upon which allergic sensitization takes place. Once sensitized, the repeated allergen exposure will lead to disease persistence. These mechanisms could also be used to explain airway wall remodelling and the susceptibility of the asthmatic lung to exacerbations provoked by respiratory viruses, air pollution episodes and exposure to biologically active allergens. Variable activation of this epithelial-mesenchymal trophic unit could also lead to the emergence of different asthma phenotypes and a more targeted approach to the treatment of these. It also raises the possibility of developing treatments that increase the lung's resistance to the inhaled environment rather than concentrating all efforts on trying to suppress inflammation once it has become established.

The irreversible component of persistent asthma

Irreversible airflow obstruction or limitation occurs in some patients with asthma, can develop early in life, and becomes more common as asthma becomes more severe. Efforts to understand irreversible airflow obstruction or limitation have been hampered by the lack of a standardized definition of the phenotype and by the lack of appropriate research models. Unfortunately, it appears that currently available asthma treatments do not prevent this important asthma complication. Herein, the evidence of an irreversible component of asthma, its underlying pathology, and the limitations of current asthma treatments are reviewed.

Rural health disparities in asthma care and outcomes

Fifty-nine million Americans (21% of the US population) live in rural areas of the United States. Compared with persons living in urban areas of the United States, rural populations have lower income, a higher rate of government versus private insurance, and decreased access to health care. Although there are reports of lower asthma prevalence in rural areas, the majority of these data have been published on international populations, with few available studies looking at American urban versus rural asthma prevalence on a national scale or comparing rural with nearby urban cohorts in the United States. A large body of literature, mainly generated from studies of rural Europe, suggests that lower prevalence might be due to beneficial effects of exposure to farm environments, but the extent to which this applies to the rural United States, where a smaller proportion of the population engages in farming, is unclear. The United States has the additional covariate of having a higher proportion of African Americans, who have a greater asthma burden than whites independent of socioeconomic status, clustered in cities. There are data indicating that rural patients have increased difficulty obtaining health care in general and limited data suggesting that they receive inferior care for asthma. Future work is needed to more clearly define asthma prevalence and morbidity among residents of the rural United States, as well as to identify interventions effective in this population.

Allergic rhinitis in patients with asthma: the Swiss LARA (Link Allergic Rhinitis in Asthma) survey

OBJECTIVE

To determine the characteristics of asthma (A) and allergic rhinitis (AR) among asthma patients in primary care practice.

RESEARCH DESIGN AND METHODS

Primary care physicians, pulmonologists, and allergologists were asked to recruit consecutive asthma patients with or without allergic rhinitis from their daily practice. Cross-sectional data on symptoms, severity, treatment and impact on quality of life of A and AR were recorded and examined using descriptive statistics. Patients with and without AR were then compared.

RESULTS

1244 asthma patients were included by 211 physicians. Asthma was controlled in 19%, partially controlled in 27% and not controlled in 54%. Asthma treatment was generally based on inhaled corticosteroids (ICS) with or without long acting beta 2 agonists (78%). A leukotriene receptor antagonist (LTRA) was used by 46% of the patients. Overall, 950 (76%) asthma patients had AR (A + AR) and 294 (24%) did not (A - AR). Compared to patients with A - AR, A + AR patients were generally younger (mean age +/- standard deviation: 42 +/- 16 vs. 50 +/- 19 years, p < 0.001) and fewer used ICS (75% vs. 88%, p < 0.001). LTRA usage was similar in both groups (46% vs. 48%). Asthma was uncontrolled in 53% of A + AR and 57% of A - AR patients. Allergic rhinitis was treated with a mean of 1.9 specific AR medications: antihistamines (77%), nasal steroids (66%) and/or vasoconstrictors (38%), and/or LTRA (42%). Rhinorrhoea, nasal obstruction, or nasal itching were the most frequently reported AR symptoms and the greatest reported degree of impairment was in daily activities/sports (55%).

CONCLUSIONS

Allergic rhinitis was more common among younger asthma patients, increased the burden of symptoms and the need for additional medication but was associated with improved asthma control. However, most asthma patients remained suboptimally controlled regardl-ess of concomitant AR.

An imbalance in C/EBPs and increased mitochondrial activity in asthmatic airway smooth muscle cells: novel targets in asthma therapy?

The asthma prevalence was increasing over the past two decades worldwide. Allergic asthma, caused by inhaled allergens of different origin or by food, is mediated by inflammatory mechanisms. The action of non-allergic asthma, induced by cold air, humidity, temperature or exercise, is not well understood. Asthma affects up to 15% of the population and is treated with anti-inflammatory and muscle relaxing drugs which allow symptom control. Asthma was first defined as a malfunction of the airway smooth muscle, later as an imbalanced immune response of the lung. Recent studies placed the airway smooth muscle again into the focus. Here we summarize the molecular biological basis of the deregulated function of the human airway smooth muscle cell as a cause or important contributor to the pathology of asthma. In the asthmatic human airway smooth muscle cells, there is: (i) a deregulation of cell differentiation due to low levels of maturation-regulating transcription factors such as CCAAT/enhancer binding proteins and peroxisome proliferator-activated receptors, thereby reducing the cells threshold to proliferate and to secrete pro-inflammatory cytokines under certain conditions; (ii) a higher basal energy turnover that is due to increased number and activity of mitochondria; and (iii) a modified feedback mechanism between cells and the extracellular matrix they are embedded in. All these cellular pathologies are linked to each other and to the innate immune response of the lung, but the sequence of events is unclear and needs further investigation. However, these findings may present the basis for the development of novel curative asthma drugs.

Risk of asthmatic episodes in children exposed to sulfur dioxide stack emissions from a refinery point source in Montreal, Canada

BACKGROUND

Little is known about the respiratory effects of short-term exposures to petroleum refinery emissions in young children. This study is an extension of an ecologic study that found an increased rate of hospitalizations for respiratory conditions among children living near petroleum refineries in Montreal (Canada).

METHODS

We used a time-stratified case-crossover design to assess the risk of asthma episodes in relation to short-term variations in sulfur dioxide levels among children 2-4 years of age living within 0.5-7.5 km of the refinery stacks. Health data used to measure asthma episodes included emergency department (ED) visits and hospital admissions from 1996 to 2004. We estimated daily levels of SO2 at the residence of children using a) two fixed-site SO2 monitors located near the refineries and b) the AERMOD (American Meteorological Society/Environmental Protection Agency Regulatory Model) atmospheric dispersion model. We used conditional logistic regression to estimate odds ratios associated with an increase in the interquartile range of daily SO2 mean and peak exposures (31.2 ppb for AERMOD peaks). We adjusted for temperature, relative humidity, and regional/urban background air pollutant levels.

RESULTS

The risks of asthma ED visits and hospitalizations were more pronounced for same-day (lag 0) SO2 peak levels than for mean levels on the same day, or for other lags: the adjusted odds ratios estimated for same-day SO2 peak levels from AERMOD were 1.10 [95% confidence interval (CI), 1.00-1.22] and 1.42 (95% CI, 1.10-1.82), over the interquartile range, for ED visits and hospital admissions, respectively.

CONCLUSIONS

Short-term episodes of increased SO2 exposures from refinery stack emissions were associated with a higher number of asthma episodes in nearby children.

The effect of sex on asthma control from the National Asthma Survey

BACKGROUND

Previous studies have demonstrated conflicting results with regard to differences in asthma control between the sexes.

OBJECTIVE

We sought to identify sex differences in short-term and long-term measures of asthma control in adults from the National Asthma Survey.

METHODS

This study analyzed data from the National Asthma Survey (Four-State sample) sponsored by the National Center for Environmental Health, Centers for Disease Control and Prevention. Asthma control was compared between the sexes based on short-term (recent symptoms, asthma attacks, and albuterol use) and long-term (asthma attacks, work days lost, and urgent-care visits and hospitalizations in the prior year) measures. Composite scores for short-term and long-term control were calculated based on any single measure of poor asthma control and based on a sum of poor asthma control measures.

RESULTS

Women were more likely to have poor short-term asthma control based on any measure (adjusted odds ratio [OR], 1.20; CI, 1.01-1.44) or sum of measures (adjusted OR, 1.24; CI, 1.08-1.53) compared with men. Women also demonstrated worse asthma control based on any uncontrolled long-term measure (adjusted OR, 1.52; CI, 1.29-1.79) or sum of measures (adjusted OR, 1.68; CI, 1.45-1.93). These findings were present despite higher reported inhaled corticosteroid use and scheduled health care visits for asthma among women.

CONCLUSIONS

Women demonstrated worse asthma control compared with men with regard to several short-term and long-term measures, despite reporting higher rates of inhaled corticosteroid use and routine asthma care visits. Further studies are needed to elucidate whether these findings are due to differences in health reporting or to pathophysiologic differences in asthma between the sexes.

Asthma progression to airway remodeling and bone marrow eosinophil responses in genetically distinct strains of mice

BACKGROUND

Patient factors that cause long-term airway remodeling are largely unidentified. This suggests that genetic differences may determine which asthmatic patients develop airway remodeling. A murine model with repeated allergen exposure leading to peribronchial fibrosis in complement factor 5 (C5)-deficient A/J mice has been used to study asthma progression. No studies have addressed the systemic effects of allergen sensitization or chronic allergen exposure on bone marrow eosinophilopoiesis in this mouse strain.

OBJECTIVE

To investigate bone marrow eosinophil responses during acute sensitization and chronic allergen exposure using genetically distinct mouse strains differing in persistent airway reactivity and remodeling.

METHODS

The C5-sufficient BALB/c and C5-deficient A/J mice were repetitively exposed to intranasal ovalbumin for 12 weeks. Subsequently, the mice were evaluated for airway eosinophilia, mucus-containing goblet cells, and peribronchial fibrosis. Both strains of mice were also acutely sensitized to ovalbumin. Bone marrow eosinophil progenitor cells and mature eosinophils were enumerated.

RESULTS

BALB/c and A/J mice have similar bone marrow responses after acute allergen exposure, with elevations in bone marrow eosinophil progenitor cell and eosinophil numbers. After chronic allergen exposure, only C5-deficient A/J mice that developed peribronchial fibrosis exhibited bone marrow eosinophilia. BALB/c mice lacked peribronchial fibrosis and extinguished accelerated eosinophil production after long-term allergen challenge.

CONCLUSIONS

Chronic airway remodeling after repeated allergen exposure in genetically different mice correlated with differences in long-term bone marrow eosinophilopoiesis. Preventing asthma from progressing to chronic airway remodeling with fibrosis may involve identifying genetically determined influences on bone marrow responses to chronic allergen exposure.

Advances in pediatric asthma in 2008: where do we go now?

This year's summary focuses on recent advances in pediatric asthma as reported in Journal publications in 2008. New National Asthma Education and Prevention Program asthma guidelines were released in 2007 with a special emphasis on asthma control. Attention was redirected to methods that could reduce impairment, specifically symptom control, and minimize risk, including exacerbations. Journal theme issues in 2008 focused on several relevant asthma topics including asthma exacerbations, exercise-induced bronchospasm, asthma and obesity, and occupational asthma. This review highlights Journal articles and related articles that reinforce principles of the guidelines and also direct us to new information that will advance asthma care for children. A major step forward will be finding ways to implement the asthma guidelines.