Clinical outcomes and inflammatory biomarkers in current smokers and exsmokers with severe asthma

Predictors for the development of progressive severity in new-onset adult asthma

BACKGROUND

A proportion of patients with adult-onset asthma have severe disease. Risk factors for an increase in asthma severity are poorly known.

OBJECTIVE

We sought to identify predictors for the development of severe asthma in adults.

METHODS

A cohort of 200 adults with new-onset asthma was prospectively followed for 2 years. At baseline, patients underwent a comprehensive assessment of clinical, functional, and inflammatory parameters. After 2 years, change in asthma severity was assessed by using the Global Initiative for Asthma score (range, 1-4), which is based on asthma control (Asthma Control Questionnaire), lung function (FEV1), and inhaled corticosteroid requirement. ANOVA and multiple regression equations were used in the analysis.

RESULTS

One hundred twenty-eight patients completed 2 years of follow-up. Seventeen (13.3%) patients had an increase in asthma severity, whereas 53 (41.4%) patients had a decrease. A lower postbronchodilator FEV1/forced vital capacity ratio and a higher number of cigarette pack years smoked at baseline were significantly associated with an increase in asthma severity at follow-up. Multiple regression equations showed that only the number of cigarette pack years smoked was independently associated with an increase in asthma severity, with an odds ratio of 1.4 (95% CI, 1.02-1.91) for every 10 pack years smoked.

CONCLUSION

A history of cigarette smoking in patients with new-onset adult asthma predicts an increase in asthma severity during the first 2 years of the disease in a dose-dependent manner.

Defining severe asthma - an approach to find new therapies

Asthma is a chronic inflammatory disease that has reached epidemic proportions worldwide. It is treatable in the majority of patients, but there is no cure. Moreover, a proportion of patients suffer from severe, difficult-to-control disease with daily symptoms and high morbidity, making it imperative that we continue to improve our understanding of the underlying mechanisms of this disease. Severe asthma is a heterogeneous condition. A systematic approach to identify specific asthma phenotypes, including clinical characteristics and inflammatory processes, is the first step toward individualized, logical therapy. This review focuses on the need to characterize severe asthma phenotypes and on novel, targeted molecular treatment options currently under development.

Association between current asthma and secondhand smoke exposure in vehicles among adults living in four US states

OBJECTIVE

Many states have implemented laws prohibiting tobacco smoking in indoor public places. However, private settings remain a major source of secondhand smoke (SHS) exposure for many people. We assessed the association between current asthma and SHS exposure in vehicles among adult never-smokers in Indiana, Kentucky, Louisiana and Mississippi.

METHODS

Data came from the 2011 Behavioral Risk Factor Surveillance System, a state-based telephone survey of US adults aged ≥18 years. Analyses were restricted to states (n=4) that administered an optional SHS module. Prevalence of self-reported asthma and past 7-day SHS exposure in vehicles was calculated by demographics, voluntary smoke-free vehicle rules and SHS exposure in homes, public places and workplaces. Logistic regression was used to assess the adjusted association between asthma and SHS exposure in vehicles.

RESULTS

Among 17 863 never-smoking adults, 7.4% reported having current asthma, whereas 12.3% reported past 7-day SHS exposure in vehicles. Among adults with asthma, SHS exposure in vehicles was lower among those with voluntary smoke-free rules compared with those without voluntary smoke-free rules (9.5% vs 56.7%, p<0.0001). Following adjustment, adults exposed to SHS in a vehicle had a higher odds of having current asthma compared with unexposed adults (OR=2.01, 95% CI 1.18 to 3.40).

CONCLUSIONS

Never-smoking adults recently exposed to SHS in a vehicle had higher odds of having current asthma compared with unexposed adults. Efforts are warranted to warn about the dangers of SHS and to encourage voluntary smoke-free rules in vehicles, especially among adults with asthma.

Arachidonic acid metabolites and enzyme transcripts in asthma are altered by cigarette smoking

BACKGROUND

Arachidonic acid metabolites are implicated in the pathogenesis of asthma although only limited information is available on the impact of current smoking history on these metabolites. The aim of the study was to examine the effect of smoking status on urinary, sputum, and plasma eicosanoid concentrations and relevant enzyme transcripts in asthma.

METHODS

In 108 smokers and never smokers with asthma and 45 healthy controls [smokers and never smokers], we measured urinary tetranor prostaglandin (PG)D2 (PGDM) and leukotriene (LT)E4 , induced sputum fluid LTB4 , LTE4 , PGD2 , and PGE2 , plasma secretory phospholipase A2 (sPLA2 ), and 11β prostaglandin F2α (11βPGF2α ), and, in a subgroup with severe asthma, airway leukocyte and epithelial cell mRNA expression levels of arachidonic acid metabolic enzymes.

RESULTS

Smokers with asthma had higher urinary LTE4 ; 83 (59, 130) vs 59 (40, 90) pg/mg creatinine, P = 0.008, and PGDM; 60 (35, 100) vs 41 (28, 59) ng/mg creatinine, P = 0.012 concentrations, respectively, and lower sputum PGE2 concentrations 80 (46, 157) vs 192 (91, 301) pg/ml, P = 0.001 than never smokers with asthma. Sputum LTB4 (P = 0.013), and plasma 11βPGF2α (P = 0.032), concentrations, respectively, were increased in smokers with asthma compared with healthy smokers. Asthma-specific and smoking-related increases (>1.5-fold expression) in arachidonate 15-lipoxygenase and gamma-glutamyltransferase transcripts were demonstrated.

CONCLUSIONS

Several arachidonic acid metabolites and enzyme transcripts involving both lipoxygenase and cyclooxygenase pathways are increased in smokers with asthma and differ from never smokers with asthma. Possibly targeting specific lipoxygenase and cyclooxygenase pathways that are activated by asthma and cigarette smoking may optimize therapeutic responses.

Advances in adult asthma diagnosis and treatment in 2013

In 2013, several themes emerged: (1) a dedicated search for new therapies using new mechanisms; (2) the importance of the plasticity of the immune system (eg, that molecules that mediate inflammation in one setting can promote its resolution and return to homeostasis in other circumstances); (3) the complex role of viruses in asthma exacerbations; (4) the similarities and differences among asthma, asthma in smokers, and chronic obstructive pulmonary disease; and (5) the importance of understanding asthma phenotypes and their stability over time. Once new therapeutics pass the initial clinical trials, patient-oriented and real-world research will be needed.

Chronic traffic pollution exposure is associated with eosinophilic, but not neutrophilic inflammation in older adult asthmatics

OBJECTIVE

Airway inflammatory patterns in older asthmatics are poorly understood despite high asthma-related morbidity and mortality. In this study, we sought to define the relationship between exposure to traffic pollutants, biomarkers in induced sputum, and asthma control in older adults.

METHODS

Induced sputum was collected from 35 non-smoking adults ≥65 years with a physician's diagnosis of asthma and reversibility with a bronchodilator or a positive methacholine challenge. Patients completed the Asthma Control Questionnaire (ACQ), and Elemental Carbon Attributable to Traffic (ECAT), a surrogate for chronic diesel particulate exposure, was determined. Equal numbers of subjects with high (≥0.39 µg/m(3)) versus low (<0.39 µg/m(3)) ECAT were included. Differential cell counts were performed on induced sputum, and myeloperoxidase (MPO) and eosinophil peroxidase (EPO) were measured in supernatants. Regression analyses were used to evaluate the relationship between sputum findings, ACQ scores, and ECAT.

RESULTS

After adjustment for potential confounders, subjects with poorly controlled asthma based on ACQ ≥ 1.5 (n = 7) had significantly higher sputum eosinophils (median = 4.4%) than those with ACQ < 1.5 (n = 28; eosinophils = 2.6%; β = 10.1 [95% CI = 0.1-21.0]; p = 0.05). Subjects with ACQ ≥ 1.5 also had significantly higher sputum neutrophils (84.2% versus 65.2%; β = 7.1 [0.2-14.6]; p = 0.05). Poorly controlled asthma was associated with higher sputum EPO (β = 2.4 [0.2-4.5], p = 0.04), but not MPO (p = 0.9). High ECAT was associated with higher eosinophils (β = 10.1 [1.8-18.4], p = 0.02) but not higher neutrophils (p = 0.6).

CONCLUSIONS

Poorly controlled asthma in older adults is associated with eosinophilic and neutrophilic inflammation. Chronic residential traffic pollution exposure may be associated with eosinophilic, but not neutrophilic inflammation in older asthmatics.