Leukotriene E(4) in urine in patients with asthma and COPD--the effect of smoking habit

Lipid mediators of inhalation exposure-induced pulmonary toxicity and inflammation

Many inhalation exposures induce pulmonary inflammation contributing to disease progression. Inflammatory processes are actively regulated via mediators including bioactive lipids. Bioactive lipids are potent signaling molecules involved in both pro-inflammatory and resolution processes through receptor interactions. The formation and clearance of lipid signaling mediators are controlled by multiple metabolic enzymes. An imbalance of these lipids can result in exacerbated and sustained inflammatory processes which may result in pulmonary damage and disease. Dysregulation of pulmonary bioactive lipids contribute to inflammation and pulmonary toxicity following exposures. For example, inhalation of cigarette smoke induces activation of pro-inflammatory bioactive lipids such as sphingolipids, and ceramides contributing to chronic obstructive pulmonary disease. Additionally, exposure to silver nanoparticles causes dysregulation of inflammatory resolution lipids. As inflammation is a common consequence resulting from inhaled exposures and a component of numerous diseases it represents a broadly applicable target for therapeutic intervention. With new appreciation for bioactive lipids, technological advances to reliably identify and quantify lipids have occurred. In this review, we will summarize, integrate, and discuss findings from recent studies investigating the impact of inhaled exposures on pro-inflammatory and resolution lipids within the lung and their contribution to disease. Throughout the review current knowledge gaps in our understanding of bioactive lipids and their contribution to pulmonary effects of inhaled exposures will be presented. New methods being employed to detect and quantify disruption of pulmonary lipid levels following inhalation exposures will be highlighted. Lastly, we will describe how lipid dysregulation could potentially be addressed by therapeutic strategies to address inflammation.

Effects of non-steroidal anti-inflammatory drugs and other eicosanoid pathway modifiers on antiviral and allergic responses: EAACI task force on eicosanoids consensus report in times of COVID-19

Non‐steroidal anti‐inflammatory drugs (NSAIDs) and other eicosanoid pathway modifiers are among the most ubiquitously used medications in the general population. Their broad anti‐inflammatory, antipyretic, and analgesic effects are applied against symptoms of respiratory infections, including SARS‐CoV‐2, as well as in other acute and chronic inflammatory diseases that often coexist with allergy and asthma. However, the current pandemic of COVID‐19 also revealed the gaps in our understanding of their mechanism of action, selectivity, and interactions not only during viral infections and inflammation, but also in asthma exacerbations, uncontrolled allergic inflammation, and NSAIDs‐exacerbated respiratory disease (NERD). In this context, the consensus report summarizes currently available knowledge, novel discoveries, and controversies regarding the use of NSAIDs in COVID‐19, and the role of NSAIDs in asthma and viral asthma exacerbations. We also describe here novel mechanisms of action of leukotriene receptor antagonists (LTRAs), outline how to predict responses to LTRA therapy and discuss a potential role of LTRA therapy in COVID‐19 treatment. Moreover, we discuss interactions of novel T2 biologicals and other eicosanoid pathway modifiers on the horizon, such as prostaglandin D2 antagonists and cannabinoids, with eicosanoid pathways, in context of viral infections and exacerbations of asthma and allergic diseases. Finally, we identify and summarize the major knowledge gaps and unmet needs in current eicosanoid research.

The mercapturomic profile of health and non-communicable diseases

The mercapturate pathway is a unique metabolic circuitry that detoxifies electrophiles upon adducts formation with glutathione. Since its discovery over a century ago, most of the knowledge on the mercapturate pathway has been provided from biomonitoring studies on environmental exposure to toxicants. However, the mercapturate pathway-related metabolites that is formed in humans—the mercapturomic profile—in health and disease is yet to be established. In this paper, we put forward the hypothesis that these metabolites are key pathophysiologic factors behind the onset and development of non-communicable chronic inflammatory diseases. This review goes from the evidence in the formation of endogenous metabolites undergoing the mercapturate pathway to the methodologies for their assessment and their association with cancer and respiratory, neurologic and cardiometabolic diseases.

Exposure to volatile organic compounds and airway inflammation

BACKGROUND

Exposure to low levels of volatile organic compounds (VOCs) in ordinary life is suspected to be related to oxidative stress and decreased lung function. This study evaluated whether exposure to ambient VOCs in indoor air affects airway inflammation.

METHODS

Thirty-four subjects from the hospital that had moved to a new building were enrolled. Symptoms of sick building syndrome, pulmonary function tests, and fractional exhaled nitric oxide (FeNO) were evaluated, and random urine samples were collected 1 week before and after the move. Urine samples were analyzed for VOC metabolites, oxidative stress biomarkers, and urinary leukotriene E4 (uLTE4) levels.

RESULTS

The level of indoor VOCs in the new building was higher than that in the old building. Symptoms of eye dryness and eye irritation, as well as the level of a xylene metabolite (o-methylhippuric acid) increased after moving into the new building (p = 0.012, p = 0.008, and p < 0.0001, respectively). For the inflammatory markers, FeNO decreased (p = 0.012 and p = 0.04, respectively) and the uLTE4 level increased (p = 0.005) after the move.

CONCLUSION

Exposure to a higher level of VOCs in everyday life could affect airway inflammation.

Lab-on-chip technology for chronic disease diagnosis

Various types of chronic diseases (CD) are the leading causes of disability and death worldwide. While those diseases are chronic in nature, accurate and timely clinical decision making is critically required. Current diagnosis procedures are often lengthy and costly, which present a major bottleneck for effective CD healthcare. Rapid, reliable and low-cost diagnostic tools at point-of-care (PoC) are therefore on high demand. Owing to miniaturization, lab-on-chip (LoC) technology has high potential to enable improved biomedical applications in terms of low-cost, high-throughput, ease-of-operation and analysis. In this direction, research toward developing new LoC-based PoC systems for CD diagnosis is fast growing into an emerging area. Some studies in this area began to incorporate digital and mobile technologies. Here we review the recent developments of this area with the focus on chronic respiratory diseases (CRD), diabetes, and chronic kidney diseases (CKD). We conclude by discussing the challenges, opportunities and future perspectives of this field.

Asthma and Obstructive Sleep Apnea

Objective:

To get a comprehensive understanding about the relationship between obstructive sleep apnea (OSA) and asthma by reviewing the epidemiology, pathophysiology, and clinical manifestation and then summarizing the latest progress on diagnosis and treatment.

Data Sources:

Articles referred in this review were mainly collected from a comprehensive search of the PubMed published in English from 1990 to 2015 with the terms “OSA” and “asthma” as the main keywords. Highly regarded older publications were also included.

Study Selection:

Information about the features of the two diseases in common, the pathophysiologic association between them and their current treatments from the literature search were identified, retrieved, and summarized.

Results:

Both OSA and asthma are very prevalent conditions. The incidences of them have kept on rising in recent years. Asthma is often accompanied by snoring and apnea, and OSA often combines with asthma, as well. They have many predisposing and aggravating factors in common. Possible shared direct mechanistic links between them include mechanical effects, intermittent hypoxia, nerve reflex, inflammation, leptin, etc. Indirect mechanistic links include medication, nose diseases, smoking, obesity, and gastroesophageal reflux disease. Since OSA presents many similar features with nocturnal asthma, some scholars termed them as a sole syndrome – “alternative overlap syndrome,” and proved that asthma symptoms in those patients could be improved through the treatment of continuous positive airway pressure.

Conclusions:

OSA and asthma are closely associated in pathogenesis, symptoms, and therapies. With the growing awareness of the relationship between them, we should raise our vigilance on the coexistence of OSA in those difficult-to-control asthmatic patients. Further studies are still needed to guide the clinical works.

Effects of tiotropium on lung function in current smokers and never smokers with bronchial asthma

The effects of tiotropium, an inhaled long-acting muscarinic antagonist, on lung function were investigated in current smokers and nonsmokers with asthma treated with inhaled corticosteroids (ICSs) and other asthma controllers: inhaled long-acting β₂ agonists, leukotriene receptor antagonists, and/or theophylline. We conducted a double-blind, placebo-controlled study of an inhaled single dose of tiotropium in 9 asthmatics currently smoking and 9 asthmatics who have never smoked in a crossover manner. Lung function was measured before and 1, 3, and 24 h after inhalation of 18 μg of tiotropium or a placebo. The primary outcome was a change in forced expiratory volume in 1 s (FEV₁) from the baseline, and the secondary outcomes were changes in peak expiratory flow rate (PEFR), V˙₅₀, and V˙₂₅. At baseline, asthmatics with and without a smoking history had a mean FEV₁ of 2590 ml and 2220 ml and were taking a mean dose of ICSs of 1208 and 1000 μg/day, respectively. The increase from the baseline FEV₁ was 169 ml and 105 ml higher at 3 h after tiotropium than after the placebo in current smokers and nonsmokers, respectively. PEFR, V˙₅₀, and V˙₂₅ were also significantly increased after tiotropium as compared with the placebo in both study groups. Changes in FEV₁ and PEFR tended to be greater in asthmatics currently smoking than in subjects who have never smoked, although there were no statistical differences at any time points. Tiotropium resulted in improved lung function and symptoms both in current smoker and nonsmoker asthmatics. These findings suggest that tiotropium will provide a new strategy for the treatment of bronchial asthma.

Asthma phenotypes: the intriguing selective intervention with Montelukast

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation and a variable course associated with various underlying mechanisms that can differ between individuals. Patients with asthma can therefore exhibit different phenotypes, a term used to define the observable characteristics of an organism resulting from the interaction between its genetic makeup and the environment. The heterogeneity of asthma has received a large amount of attention in the last few years in order to better tailor treatment according to the different clinical and biological phenotypes of the disease. Specific asthma phenotypes may require an approach to treatment sometimes different from that recommended by current guidelines, so a personalized approach to asthma pharmacotherapy is recommended. Growing evidence suggests that leukotrienes play an important role in the pathogenesis of bronchial asthma. The mechanisms of action of leukotriene-receptor antagonists theoretically predict a good response in some asthma “phenotypes”.In this article we have performed an analysis of the recent literature (controlled clinical trials and real-life studies) about a possible selective intervention with Montelukast in specific asthma phenotypes.

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.

Low-level environmental tobacco smoke exposure and inflammatory biomarkers in children with asthma

OBJECTIVE

The effects of low-level environmental tobacco smoke (ETS) exposure, on asthma control, lung function and inflammatory biomarkers in children with asthma have not been well studied. The objective of the study was to assess ETS exposure in school-age children with asthma whose parents either deny smoking or only smoke outside the home, and to assess the impact of low-level ETS exposure on asthma control, spirometry and inflammatory biomarkers.

METHODS

Forty patients age 8-18 years with well-controlled, mild-to-moderate persistent asthma treated with either inhaled corticosteroids (ICS) or montelukast were enrolled. Subjects completed an age-appropriate Asthma Control Test and a smoke exposure questionnaire, and exhaled nitric oxide (FeNO), spirometry, urinary cotinine and leukotriene E(4) (LTE(4)) were measured. ETS-exposed and unexposed groups were compared.

RESULTS

Only one parent reported smoking in the home, yet 28 (70%) subjects had urinary cotinine levels ≥1 ng/ml, suggesting ETS exposure. Seven subjects (18%) had FeNO levels >25parts per billion, six of whom were in the ETS-exposed group. In the ICS-treated subjects, but not in the montelukast-treated subjects, ETS exposure was associated with higher urinary LTE(4), p = 0.04, but had no effect on asthma control, forced expiratory volume in 1 s or FeNO.

CONCLUSIONS

A majority of school-age children with persistent asthma may be exposed to ETS, as measured by urinary cotinine, even if their parents insist they don't smoke in the home. Urinary LTE(4) was higher in the ETS-exposed children treated with ICS, but not in children treated with montelukast.

Integrating evidence for managing asthma in patients who smoke

Cigarette smoking among asthma patients is associated with worsening symptoms and accelerated decline in lung function. Smoking asthma is also characterized by increased levels of neutrophils and macrophages, and greater small airway remodeling, resulting in increased airflow obstruction and impaired response to corticosteroid therapy. As a result, smokers are typically excluded from asthma randomized controlled trials (RCTs). The strict inclusion/exclusion criteria used by asthma RCTs limits the extent to which their findings can be extrapolated to the routine care asthma population and to reflect the likely effectiveness of therapies in subgroups of particular clinical interest, such as smoking asthmatics. The inclusion of smokers in observational asthma studies and pragmatic trials in asthma provides a way of assessing the relative effectiveness of different treatment options for the management of this interesting clinical subgroup. Exploratory studies of possible treatment options for smoking asthma suggest potential utility in: prescribing higher-dose ICS; targeting the small airways of the lungs with extra-fine particle ICS formulations; targeting leukotreines, and possibly also combinations of these options. However, further studies are required. With the paucity of RCT data available, complementary streams of evidence (those from RCTs, pragmatic trials and observational studies) need to be combined to help guide judicious prescribing decisions in smokers with asthma.

Vascular endothelial growth factor and cysteinyl leukotrienes in sputum supernatant of patients with asthma

BACKGROUND

Vascular endothelial growth factor (VEGF) is considered to be the most important angiogenic factor in asthma. Cysteinyl leukotrienes (Cyst-LTs) have been implicated in vascular permeability in asthma. Cyst-LTs receptor antagonists modulate vascular permeability by reducing VEGF expression.

OBJECTIVE

We aimed to determine the levels of VEGF and Cyst-LTs in sputum supernatants of patients with asthma and to investigate possible associations within them and with airway vascular permeability (AVP) index. Possible confounding factors were also assessed.

METHODS

One hundred twenty one patients with asthma (38 with severe refractory asthma, 41 smokers) and 30 healthy subjects (15 smokers) were studied. All subjects underwent lung function tests, and sputum induction for cell count identification and VEGF, Cyst-LTs, measurement in supernatants. AVP index was also assessed.

RESULTS

Both VEGF & Cyst-LTs (pg/ml) levels were significantly elevated in patients with asthma compared to normal subjects (median, interquartile ranges 845 [487-1034] vs. 432 (327-654) and 209 [171-296] vs. 92 [75-114] respectively, p < 0.001 for both). Multivariate regression analysis in the whole group showed a significant association of Cyst-LTs levels in sputum supernatants with VEGF levels in sputum supernatants and AVP index. A similar positive association was observed between VEGF levels in sputum supernatants and AVP index. The presence of Severe asthma was a significant covariate for both associations.

CONCLUSION

Our results indicate that Cyst-LTs may modulate vascular permeability by up-regulating VEGF expression. The above effect seems to be affected by asthma severity.

Influences of smoking and aging on allergic airway inflammation in asthma

Asthma is a heterogeneous disease with varying phenotypes and numerous risk factors. This condition results from complex interactions between genetic and environmental factors, and active smoking is one of these risk factors. The effects of aging should also be taken into account in these interactions. From an epidemiological standpoint, smokers and/or elderly patients with asthma are not small part in the total population with asthma. Furthermore, both smoking and aging are important risk factors for severe asthma. This review discusses the potential effects of smoking and aging on healthy subjects and patients with asthma, particularly from the perspective of inflammatory changes. First we show evidence that smokers and the elderly have increased neutrophil counts in their airways, which may have impacts on their clinical characteristics of elderly smokers with asthma. Secondly, on the basis of our recent findings on the interactions between smoking and aging in patients with asthma, we propose that IgE/eosinophilic inflammation should not be underestimated in elderly smokers with asthma, particularly those who are atopic. This review may expand our understanding of the effects of smoking and aging on asthma with a new perspective of an old issue.

Passive smoking induces leukotriene production in children: influence of asthma

BACKGROUND

Passive smoking is associated with poor asthma control in children, but the mechanism is unknown. Leukotrienes are involved in the asthma pathogenesis and their synthesis is increased in adult subjects who actively smoke.

OBJECTIVE

To evaluate whether passive smoking, as assessed by urinary cotinine levels, increases leukotriene production in children with or without asthma.

METHODS

This was a prospective, cross-sectional study in which children with stable intermittent asthma (without exacerbation) and healthy control children were studied through spirometry and urinary concentrations of cotinine and leukotriene E(4) (LTE(4)). Both groups were balanced to include children with and without passive smoking.

RESULTS

Ninety children (49 with asthma and 41 controls, 54.4% females) aged 9 years (range, 5-13 years) were studied. Urinary LTE(4) concentrations were progressively higher as cotinine levels increased (r(S) = 0.23, p = .03). LTE(4) also correlated with body mass index (BMI) (r(S) = 0.30, p = .004), and multiple regression analysis revealed that BMI was even more influential than cotinine for determining LTE(4) levels. LTE(4) concentrations were unrelated with gender, age, or spirometry. In turn, cotinine inversely correlated with forced expiratory volume in one second (FEV(1)) (r(S) = -0.22, p = .04) and forced vital capacity (FVC) (r(S) = -0.25, p = .02), but when analyzed by groups, these relationships were statistically significant only in children with asthma.

CONCLUSIONS

Exposure to environmental tobacco smoke, as assessed by urinary cotinine levels, was associated with an increased urinary concentration of LTE(4), although BMI exerted more influence in determining its concentration. Urinary cotinine was associated with decreased lung function, mainly in children with asthma.

Effect of montelukast for treatment of asthma in cigarette smokers

OBJECTIVE

Many asthmatic patients are unable to quit cigarettes; therefore information is needed on treatment options for smokers. This study evaluates 10 mg/d montelukast and 250 μg of fluticasone propionate twice daily, each compared with placebo, in patients with self-reported active smoking (unable to quit) and asthma.

METHODS

Patients (ages 18-55 years, with asthma [≥1 year], FEV1 of 60% to 90% of predicted value, airway reversibility [≥12%], and self-reported active smoking [≥0.5 to ≤2 packs per day]) were randomized (after a 3-week, single-blind, placebo, run-in period) to 1 of 3 parallel, 6-month, double-blind treatment arms. The primary efficacy end point was the percentage of days with asthma control during treatment. Adverse experiences (AEs) were also evaluated.

RESULTS

There were 347, 336, and 336 patients randomized to montelukast, fluticasone, and placebo, respectively. The mean percentage of days with asthma control over 6 months of treatment was 45% (montelukast, P < .05 vs placebo), 49% (fluticasone, P < .001 vs placebo), and 39% (placebo); the difference between montelukast and fluticasone was not significant (P = .14). Patients with a smoking history of ≤11 pack years (the median value) tended to show more benefit with fluticasone, whereas those with a smoking history of >11 pack years tended to show more benefit with montelukast. AEs occurred in similar proportions among treatment groups.

CONCLUSIONS

In a population of asthmatic patients actively smoking cigarettes, both 10 mg/d montelukast and 250 μg of fluticasone propionate twice daily significantly increased the mean percentage of days with asthma control compared with placebo.

The adult asthmatic

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

Relationship between exhaled nitric oxide and exposure to low-level environmental tobacco smoke in children with asthma on inhaled corticosteroids

OBJECTIVES

The relationship between exhaled nitric oxide (FeNO) and asthma severity or control is inconsistent. Active smoking lowers FeNO, but the relationship between passive smoking and FeNO is less clear. Children may be exposed to low-level environmental tobacco smoke (ETS) or thirdhand smoke, even if parents avoid smoking in the presence of their children. Our hypothesis was that FeNO is lower in children with asthma exposed to low-level ETS when compared with those who are not exposed.

METHODS

Children with stable asthma, 8-18 years of age, on low- or medium-dose inhaled corticosteroids (ICS) were enrolled. Spirometry, Asthma Control Questionnaire (ACQ), FeNO, exhaled breath condensate pH (EBC pH), and EBC ammonia were compared between children with and without ETS exposure as determined by urinary cotinine.

RESULTS

Thirty-three subjects were enrolled, of which 10 (30%) had urinary cotinine levels ≥1 ng/ml. There were no significant differences between the two groups in age, sex, BMI percentile, atopy status, FEV(1), EBC pH, or EBC ammonia. Median ACQ was 0.29 (IQR: 0.22-0.57) for those with cotinine levels <1 ng/ml and 0.64 (IQR: 0.57-1.1) for those with cotinine levels of ≥1 ng/ml, p = .02. Median FeNO (ppb) was 23.9 (IQR: 15.2-34.5) for unexposed subjects and 9.6 (IQR: 5.1-15.8) for exposed subjects, p = .008.

CONCLUSIONS

Children with asthma on low to medium doses of ICS and recent low-level ETS exposure have lower FeNO levels when compared with non-ETS-exposed subjects. Exposure to low-level ETS or thirdhand smoke may be an important variable to consider when interpreting FeNO as a biomarker for airway inflammation.

The effects of cigarette smoke on airway inflammation in asthma and COPD: therapeutic implications

Asthma and COPD are two chronic inflammatory disorders of the airway characterized by airflow limitation. While many similarities exist between these two diseases, they are pathologically distinct due to the involvement of different inflammatory cells; predominantly neutrophils, CD8 lymphocytes in COPD and eosinophils and CD4 lymphocytes in asthma. Cigarette smoking is associated with accelerated decline of lung function, increased mortality, and worsening of symptoms in both asthma and COPD. Furthermore, exposure to cigarette smoke can alter the inflammatory mechanisms in asthma to become similar to that seen in COPD with increasing CD8 cells and neutrophils and may therefore alter the response to therapy. Cigarette smoke exposure has been associated with a poor response to inhaled corticosteroids which are recommended as first line anti-inflammatory medications in asthma and as an add-on therapy in patients with severe COPD with history of exacerbations. While the main proposed mechanism for this altered response is the reduction of the histone deacetylase 2 (HDAC2) enzyme system, other possible mechanisms include the overexpression of GR-β, activation of p38 MAPK pathway and increased production of inflammatory cytokines such as IL-2, 4, 8, TNF-α and NF-Kß. Few clinical trials suggest that leukotriene modifiers may be an alternative to corticosteroids in smokers with asthma but there are currently no drugs which effectively reduce the progression of inflammation in smokers with COPD. However, several HDAC2 enhancers including low dose theophylline and other potential anti-inflammatory therapies including PDE4 inhibitors and p38 MAPK inhibitors are being evaluated.

Exhaled nitric oxide and exhaled breath condensate pH as predictors of sputum cell counts in optimally treated asthmatic smokers

BACKGROUND AND OBJECTIVE

Smoking is thought to modify the pattern of airway inflammation. Induced sputum provides useful information on cellular phenotype in inflammatory airways disorders; however, it is time-consuming and difficult to implement in everyday clinical practice. The aim of this study was to determine whether exhaled NO (FeNO) and exhaled breath condensate (EBC) pH differed in asthmatic smokers compared with asthmatic non-smokers and healthy subjects, and to evaluate the performance of FeNO and EBC pH for predicting the cellular phenotype of induced sputum.

METHODS

Asthmatic smokers (n = 40) and non-smoking asthmatic patients (n = 43) were recruited for the study. Healthy smoking (n = 30) or non-smoking (n = 30) subjects served as controls. FeNO and EBC pH were measured and all subjects underwent sputum induction for assessment of cell counts.

RESULTS

EBC pH was significantly lower in asthmatic smokers compared with non-smokers (P < 0.01). FeNO levels were also significantly lower in asthmatic smokers compared with non-smokers (P < 0.001). EBC pH was inversely associated with sputum eosinophils in both asthmatic smokers and non-smokers (P < 0.001), whereas it was inversely associated with sputum neutrophils only in asthmatic smokers (P < 0.001). FeNO was positively associated with sputum eosinophils both in asthmatic smokers and non-smokers (P < 0.001) but was not associated with sputum neutrophils. In asthmatic smokers, FeNO was a better predictor of sputum eosinophilia, whereas EBC pH was a better predictor of sputum neutrophilia. A combination of FeNO ≤ 14 ppb together with EBC pH > 7.20 predicted the paucigranulocytic induced sputum phenotype.

CONCLUSIONS

EBC pH and FeNO levels were significantly lower in asthmatic smokers compared with non-smokers. Combined specific cut-off levels for FeNO and EBC pH may predict the paucigranulocytic phenotype in asthmatic smokers.

Body mass index is associated with leukotriene inflammation in asthmatics

BACKGROUND

Obesity and asthma are characterized by the presence of inflammation. Leptin and adiponectin are circulating hormones produced by adipose tissue that regulate several metabolic and inflammatory functions. We aimed to determine whether obesity influences asthmatic inflammation as well as the contribution of leptin or/and adiponectin to a possible linkage between asthmatic and obesity-related inflammation.

MATERIALS AND METHODS

One hundred patients with asthma and 60 healthy controls were studied. Subjects who had a comorbid illness that could interfere with the proposed tests were excluded. All subjects were divided into three groups (normal range, pre-obese, obese) according to the criteria of the current WHO international classification for body mass index (BMI). Possible associations between variables expressing airway inflammation, bronchial hyper-responsiveness, systemic inflammation and obesity, as assessed by BMI, were evaluated. Leptin and adiponectin were also measured and were associated with asthma airway and systemic inflammatory variables to elucidate possible associations.

RESULTS

Obese patients had significant higher values of LTE(4) /creatinine in urine compared with pre-obese and normal range ones. In a linear regression model, the only significant associations were those between BMI and LTE(4) /creatinine in urine. Using the same model, log leptin and log adiponectin presented positive and negative associations, respectively with LTE(4) /creatinine in urine. No other significant associations were observed in both patients and healthy subjects.

CONCLUSIONS

In a selected cohort of asthmatic patients, obesity is significantly associated with increased urinary leukotriene levels. Alterations of leptin/adiponectin balance may be related to the presence of leukotriene inflammation in obese asthmatic patients.

Challenges of treating asthma in people who smoke

Cigarette smoking is common in asthma and is associated with poor symptom control and a reduced therapeutic response to inhaled and oral corticosteroids as compared with nonsmokers with asthma. This review examines the range of adverse health effects of smoking in asthma, the inflammatory mechanisms that may influence the efficacy of current drugs and discusses potential future therapeutic directions.

Optimizing maintenance therapy in pediatric asthma

PURPOSE OF REVIEW

There are different phenotypes of asthma, with phenotype-specific differences in medication response observed.

RECENT FINDINGS

Tobacco smoke exposure reduces corticosteroid responsiveness. Treatment for tobacco smoke-triggered asthma must start with treatment of tobacco dependence. Obesity-associated asthma responds to weight loss and treatment of comorbidities. Immunotherapy and omalizumab are specific therapies for atopic asthma, though its use is limited by expense, inconvenience, need for injections, and toxicities. Leukotriene modifier response is more prominent in viral-triggered asthma. Research on intermittent escalation of controller therapy for asthma shows best results when escalation is substantial and early. Inhaled corticosteroid medications in low-to-moderate doses remain the most important maintenance medication for a broad variety of asthma phenotypes, reducing both impairment and risk. When impairment is not fully controlled by an inhaled corticosteroid, combination with a long-acting beta-agonist, leukotriene modifier, or theophylline can be effective. Inhaled corticosteroid use in children does not appear to influence airway caliber or asthma severity after the medication is stopped.

SUMMARY

Optimizing maintenance therapy for asthma is not one size fits all. It is important to assess the asthma phenotype in addition to the symptom pattern, in determining optimal maintenance therapy.

Hypoxia-mediated expression of 5-lipoxygenase-activating protein involves HIF-1alpha and NF-kappaB and microRNAs 135a and 199a-5p

Hypoxia occurs in a number of pathological states, such as pulmonary, hematological, and cardiovascular disorders. In this study, we examined the molecular mechanism by which hypoxia contributes to increased leukotriene formation. Our studies showed hypoxia augmented the expression of 5-lipoxygenase activating protein (FLAP), a key enzyme in leukotriene formation, in both human pulmonary microvascular endothelial cells and a transformed human brain endothelial cell line. Hypoxia-induced FLAP mRNA expression involved activation of NADPH-oxidase, PI-3 kinase, mitogen-activated protein kinase, NF-kappaB, and hypoxia-inducible factor (HIF)-1alpha. Hypoxia-induced FLAP promoter activity was attenuated on mutation of hypoxia-response elements (HREs) and NF-kappaB binding motif in the FLAP promoter. Hypoxia also augmented binding of HIF-1alpha to HREs in FLAP promoter as demonstrated by EMSA with nuclear extracts. Furthermore, chromain immunoprecipitation analysis showed HIF-1alpha bound to HREs in native chromatin obtained from hypoxia-treated cells. Next, we examined the role of HIF-1alpha regulated microRNAs on FLAP expression. Our studies showed decreased expression of miR-135a and miR-199a-5p in response to hypoxia. However, overexpression of anti-miR-135a and anti-miR-199a-5p oligonucleotides led to a several fold increased FLAP mRNA and protein expression. These studies demonstrate for the first time that hypoxia-mediated FLAP expression is regulated by HREs and NF-kappaB site in its promoter, and negatively regulated by miR-135a and miR-199a-5p, which target the 3'-UTR of FLAP mRNA. An understanding of these regulatory pathways provides new avenues to ameliorate leukotriene formation and hence reactive airway disease, and inflammation in individuals who have sickle cell disease.

The acute effect of smoking in healthy and asthmatic smokers

BACKGROUND

Acute exposure to cigarette smoke is related to airway and systemic inflammation and oxidative stress. Little is known about the acute effect of cigarette smoking in smoking asthmatics. The aim of this study was to evaluate the acute effect of smoking in airway and systemic inflammation and oxidative stress in normal smokers and patients with properly treated well-controlled persistent asthma.

MATERIALS AND METHODS

Ten normal smokers and 10 smokers with moderate persistent asthma controlled with LABA and ICS were recruited. Subjects refrained from smoking for at least 12 h prior to their inclusion. We compared the effects of smoking of two cigarettes on airway obstruction, airway inflammation and oxidative stress [by measuring fraction of exhaled nitric oxide (FeNO), plus pH and 8-isoprostane in exhaled breath condensate (EBC)] before and 30, 90 and 180 min after smoking. Furthermore, we evaluated systemic oxidative stress, C-reactive protein (CRP) and serum amyloid A (SAA) and urine leukotriene E(4) (LTE(4)) before and 180 min after smoking.

RESULTS

No differences were observed in EBC pH and 8-isoprostane, FeNO and systemic oxidative stress between the groups at baseline. In asthmatics, EBC pH decreased 30 min and EBC 8-isoprostane increased 90 min after smoking (P = 0.039 and P = 0.029 respectively), which was not evident in smoking controls. Serum oxidative stress increased only in asthmatic smokers at 180 min (P = 0.001). No differences were observed in SAA, CRP and urine LTE(4) levels before and after smoking.

CONCLUSION

Acute smoking has more deleterious effects in well-controlled properly treated asthmatic smokers compared with matched normal smokers.

Leukotriene C4 synthase and ischemic cardiovascular disease and obstructive pulmonary disease in 13,000 individuals

Ischemic cardiovascular disease and obstructive pulmonary disease involve inflammation. Leukotrienes may be important pro-inflammatory mediators. We tested the hypothesis that the (-1072)G > A and (-444)A > C promoter polymorphisms of leukotriene C4 synthase confer risk of transient ischemic attack (TIA), ischemic stroke, ischemic heart disease (IHD), asthma, and chronic obstructive pulmonary disease (COPD). We genotyped individuals from the Danish general population, the Copenhagen City Heart Study, and Danish patients with IHD/coronary atherosclerosis, the Copenhagen Ischemic Heart Disease Study. We used prospective (n = 10,386), cross-sectional (n = 10,386), and case-control (n = 2392 + 5012) designs. Allele frequency was 0.07 for (-1072)A and 0.29 for (-444)C. Cumulative incidence for TIA was higher for (-1072)AA versus GG genotype (log-rank: p < 0.001), and lower for (-444)CC versus AA genotype (log-rank: p = 0.03). Cumulative incidence for ischemic stroke was also lower for (-444)CC versus AA genotype (log-rank: p = 0.04). Multifactorially adjusted hazard ratios for TIA were 5.2(95% CI:1.9-14) for (-1072)AA versus GG genotype, and 0.4(0.2-1.0) for (-444)CC versus AA genotype. Corresponding values were 1.9 (0.7-5.2) and 0.7 (0.5-1.0) for ischemic stroke, and 0.8 (0.4-1.6) and 1.0 (0.9-1.2) for IHD. In the case-control study, corresponding multifactorially adjusted odds ratios for IHD/coronary atherosclerosis were 0.5 (0.2-1.3) and 1.2 (1.0-1.5). These genotypes were not associated with risk of asthma or COPD. Leukotriene C4 synthase promoter genotypes influence risk of TIA and ischemic stroke, but not risk of IHD/coronary atherosclerosis, asthma, or COPD.

Increased levels of angiopoietin-2 in induced sputum from smoking asthmatic patients

BACKGROUND

Active cigarette smoking has detrimental effects on asthma morbidity and severity. Angiopoietin-1 has been shown to protect the microvessels against plasma leakage, whereas angiopoietin-2 enhances vascular permeability and subsequently induces airway mucosal oedema. Therefore, it is recently thought that angiopoietin-2 may contribute to the pathophysiology of asthma.

OBJECTIVE

To determine whether angiopoietin-2 levels in the airways are associated with clinical profiles in smoking asthmatics.

METHODS

We measured angiopoietin-1 and -2 levels in induced sputum in 35 normal controls (18 non-smokers and 17 smokers) and 49 asthmatics (24 non-smokers and 25 smokers) before and after inhaled beclomethasone dipropionate (BDP: 800 microg/day) therapy for 12 weeks.

RESULTS

Angiopoietin-1 and -2 levels in induced sputum were significantly higher in asthmatics than in normal controls. Moreover, angiopoietin-2 levels were significantly higher in smoking asthmatics than in non-smoking asthmatics (P=0.0001). The airway vascular permeability index was also higher in smoking asthmatics than in non-smoking asthmatics. Moreover, the angiopoietin-2 level was positively correlated with the airway vascular permeability index (non-smoking asthmatics: r=0.87, P<0.001, smoking asthmatics: r=0.64, P=0.002). After BDP therapy, angiopoietin-1 levels were significantly decreased in non-smoking asthmatics, smoking-cessation asthmatics, and active-smoking asthmatics. In contrast, angiopoietin-2 levels did not differ from before to after BDP therapy in non-smoking asthmatics and active-smoking asthmatics. However, its levels were significantly decreased from before to after BDP therapy in smoking-cessation asthmatics (P=0.002). Although forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC) before BDP therapy was comparable in all subgroups, this parameter after BDP therapy was significantly lower in active-smoking asthmatics than in non-smoking and smoking-cessation asthmatics. Moreover, the reduction in angiopoietin-2 levels after BDP therapy in smoking-cessation asthmatics was significantly correlated with an improvement in FEV(1)/FVC.

CONCLUSION

Angiopoietin-2 levels were elevated in the airways of smoking asthmatics, and its levels were associated with impaired airway responses.

Noninvasive evaluation of airway inflammation in asthmatic patients who smoke: implications for application in clinical practice

BACKGROUND

Despite the limited pathological data in asthmatic patients who smoke, it is thought that cigarette smoking may modify airway inflammation.

OBJECTIVES

To summarize the major clinical studies that have used samples obtained by noninvasive techniques, such as blood, urine, exhaled breath condensate (EBC), fractional exhaled nitric oxide (FeNO), and induced sputum, for the evaluation of airway inflammation and the response to treatment in asthmatic patients who smoke and to evaluate which biomarkers have been adequately validated to be used in routine clinical practice.

DATA SOURCES

In this review, we collected the available literature that addressed this topic. We searched the MEDLINE database using a combination of the following keywords: smoking or asthma or inflammation or mechanisms or exhaled nitric oxide or induced sputum or EBC.

STUDY SELECTION

We selected the articles that most adequately addressed this topic for inclusion in this review.

RESULTS

Smoking significantly influences FeNO and negatively affects its concentration, although FeNO can distinguish steroid-naive asthmatic smokers from nonasthmatic smokers. Sputum neutrophilia is the predominant finding in induced sputum in asthmatic patients who smoke but inflammatory mediators derived either from neutrophils or from a T(H)1 response can also be measured in the supernatants. EBC gives the opportunity to evaluate neutrophil-derived cytokines, airway acidification, and plausible protective mechanisms in smoking asthma.

CONCLUSIONS

Despite the encouraging updated results, the introduction of noninvasive techniques in daily clinical practice requires the reworking of some methodologic pitfalls and the identification of a reliable biomarker that is reproducible, possesses normal values, and provides information for the underlying inflammatory process and the response to treatment.

Smoking affects response to inhaled corticosteroids or leukotriene receptor antagonists in asthma

RATIONALE

One-quarter to one-third of individuals with asthma smoke, which may affect response to therapy and contribute to poor asthma control.

OBJECTIVES

To determine if the response to an inhaled corticosteroid or a leukotriene receptor antagonist is attenuated in individuals with asthma who smoke.

METHODS

In a multicenter, placebo-controlled, double-blind, double-dummy, crossover trial, 44 nonsmokers and 39 light smokers with mild asthma were assigned randomly to treatment twice daily with inhaled beclomethasone and once daily with oral montelukast.

MEASUREMENTS AND MAIN RESULTS

Primary outcome was change in prebronchodilator FEV(1) in smokers versus nonsmokers. Secondary outcomes included peak flow, PC(20) methacholine, symptoms, quality of life, and markers of airway inflammation. Despite similar FEV(1), bronchodilator response, and sensitivity to methacholine at baseline, subjects with asthma who smoked had significantly more symptoms, worse quality of life, and lower daily peak flow than nonsmokers. Adherence to therapy did not differ significantly between smokers and nonsmokers, or between treatment arms. Beclomethasone significantly reduced sputum eosinophils and eosinophil cationic protein (ECP) in both smokers and nonsmokers, but increased FEV(1) (170 ml, p = 0.0003) only in nonsmokers. Montelukast significantly increased a.m. peak flow in smokers (12.6 L/min, p = 0.002), but not in nonsmokers.

CONCLUSIONS

In subjects with mild asthma who smoke, the response to inhaled corticosteroids is attenuated, suggesting that adjustments to standard therapy may be required to attain asthma control. The greater improvement seen in some outcomes in smokers treated with montelukast suggests that leukotrienes may be important in this setting. Larger prospective studies are required to determine whether leukotriene modifiers can be recommended for managing asthma in patients who smoke.