The environmental pollutant pyrene induces the production of IL-4

Children's exposure to polycyclic aromatic hydrocarbon (PAHs): a review on urinary 1-hydroxypyrene and associated health effects

This article reviewed the published studies on the environmental exposure to polycyclic aromatic hydrocarbons (PAHs) among children and assessed the urinary 1-hydroxypyrene (1-OHP) level as a biomarker of exposure to PAHs. The current knowledge of the potential health effects of increased 1-OHP in children was reviewed. Additionally, the influence of genetic polymorphism on the urinary 1-OHP level was discussed in this review. The assembled data showed that children who are attending schools or living close to industrial and polluted urban areas might have greater exposure to higher concentrations of PAHs with a higher level of urinary 1-OHP when compared to those children living in rural areas. Urinary 1-OHP may be a reliable biomarker for determining the genotoxic effects, oxidative stress and inflammation caused by exposure to PAHs. Strong research evidence indicated that the total body burden of PAHs should be evaluated by biomonitoring of 1-OHP in line with other urinary PAHs metabolites (with 2-3 rings) to evaluate recent total exposure to PAHs. Overall, the study suggests implementing a mitigation plan to combat air pollution to provide a cleaner environment for children.

Intra-Airway Treatment with Synthetic Lipoxin A4 and Resolvin E2 Mitigates Neonatal Asthma Triggered by Maternal Exposure to Environmental Particles

Particulate matter in the air exacerbates airway inflammation (AI) in asthma; moreover, prenatal exposure to concentrated urban air particles (CAPs) and diesel exhaust particles (DEPs) predisposes the offspring to asthma and worsens the resolution of AI in response to allergens. We previously tested the hypothesis that such exposure impairs the pathways of specialized proresolving mediators that are critical for resolution and found declined Lipoxin A4 (LxA4) and Resolvin E2 (RvE2) levels in the "at-risk" pups of exposed mothers. Here, we hypothesized that supplementation with synthetic LxA4 or RvE2 via the airway can ameliorate AI after allergen exposure, which has not been tested in models with environmental toxicant triggers. BALB/c newborns with an asthma predisposition resultant from prenatal exposure to CAPs and DEPs were treated once daily for 3 days with 750 ng/mouse of LxA4 or 300 ng/mouse of RvE2 through intranasal instillation, and they were tested with the intentionally low-dose ovalbumin protocol that elicits asthma in the offspring of particle-exposed mothers but not control mothers, mimicking the enigmatic maternal transmission of asthma seen in humans. LxA4 and RvE2 ameliorated the asthma phenotype and improved AI resolution, which was seen as declining airway eosinophilia, lung tissue infiltration, and proallergic cytokine levels.

Synthesis and Optical Properties of a Series of Push-Pull Dyes Based on Pyrene as the Electron Donor

Fifteen push-pull dyes comprising the tetracyclic polyaromatic pyrene have been designed and synthesized. The optical properties of the fifteen dyes have been examined in twenty-two solvents of different polarities. Surprisingly, contrarily to what is classically observed for push-pull dyes of D-π-A structures, a negative solvatochromism could be found for numerous dyes. The photoluminescence and thermal properties of the dyes were also examined. Theoretical calculations were carried out to support the experimental results.

Impact of Reactive Species on Amino Acids-Biological Relevance in Proteins and Induced Pathologies

This review examines the impact of reactive species RS (of oxygen ROS, nitrogen RNS and halogens RHS) on various amino acids, analyzed from a reactive point of view of how during these reactions, the molecules are hydroxylated, nitrated, or halogenated such that they can lose their capacity to form part of the proteins or peptides, and can lose their function. The reactions of the RS with several amino acids are described, and an attempt was made to review and explain the chemical mechanisms of the formation of the hydroxylated, nitrated, and halogenated derivatives. One aim of this work is to provide a theoretical analysis of the amino acids and derivatives compounds in the possible positions. Tyrosine, methionine, cysteine, and tryptophan can react with the harmful peroxynitrite or ^•OH and ^•NO₂ radicals and glycine, serine, alanine, valine, arginine, lysine, tyrosine, histidine, cysteine, methionine, cystine, tryptophan, glutamine and asparagine can react with hypochlorous acid HOCl. These theoretical results may help to explain the loss of function of proteins subjected to these three types of reactive stresses. We hope that this work can help to assess the potential damage that reactive species can cause to free amino acids or the corresponding residues when they are part of peptides and proteins.

Gestational exposure to titanium dioxide, diesel exhaust, and concentrated urban air particles affects levels of specialized pro-resolving mediators in response to allergen in asthma-susceptible neonate lungs

Maternal gestational exposures to traffic and urban air pollutant particulates have been linked to increased risk and/or worsening asthma in children; however, mechanisms underlying this vertical transmission are not entirely understood. It was postulated that gestational particle exposure might affect the ability to elicit specialized proresolving mediator (SPM) responses upon allergen encounter in neonates. Lipidomic profiling of 50 SPMs was performed in lungs of neonates born to mice exposed to concentrated urban air particles (CAP), diesel exhaust particles (DEP), or less immunotoxic titanium dioxide particles (TiO2). While asthma-like phenotypes were induced with identical eosinophilia intensity across neonates of all particle-exposed mothers, levels of LXA4, HEPE and HETE isoforms, and HDoHe were only decreased by CAP and DEP only but not by TiO2. However, RvE2 and RvD1 were inhibited by all particles. In contrast, isomers of Maresin1 and Protectin D1 were variably elevated by CAP and DEP, whereas Protectin DX, PGE2, and TxB2 were increased in all groups. Only Protectin D1/DX, MaR1(n-3,DPA), 5(S),15(S)-DiHETE, PGE2, and RvE3 correlated with eosinophilia but the majority of other analytes, elevated or inhibited, showed no marked correlation with inflammation intensity. Evidence indicates that gestational particle exposure leads to both particle-specific and nonspecific effects on the SPM network.

Association between exposure to chemical mixtures in relation to serum total IgE among adults 19-86 years old

There is a scarcity of studies on the effects of mixed chemicals on total IgE. We aim to assess whether there is a link between chemical mixtures (blood and urine of 26 chemicals including lead, mercury, cadmium, t,t-muconic acid, benzylmercapturic acid , 1-hydroxypyrene, 2-naphthol, 2-hydroxyfluorene, 1-hydroxyphenanthrene, mono-(2-ethyl-5-hydroxyhexyl) phthalate, mono-(2-ethyl-5-oxohexyl) phthalate, mono-n-butyl phthalate, mono-benzyl phthalate, mono-(2-ethyl-5-carboxypentyl) phthalate, mono-carboxyoctyl phthalate, mono-carboxy-isononly phthalate, mono (3-carboxypropyl) phthalate, bisphenol A, bisphenol F, bisphenol S, triclosan, methylparaben, ethylparaben, propylparaben, 3-phenoxybenzoic acid, and cotinine), and total IgE in 3,642 Korean adults aged ≥ 19. The effects of mixed chemical exposure on total IgE were identified using linear regression models, weighted quantile sum (WQS) regression, quantile g-computation (qgcomp), and Bayesian kernel machine regression (BKMR). The most relevant factors linked with IgE, according to the linear regression models, were blood or urine mercury and urine bisphenol A levels, with significant trends detected for these chemical tertiles (p < 0.01). The WQS index was significantly linked with ln2-transformed levels of serum total IgE (β = 0.30, 95 %CI 0.25-0.32). The qgcomp index also found a significant link between chemicals and ln2-transformed levels of serum total IgE (β = 0.52, 95 %CI 0.21-0.82), and elevated serum total IgE levels (OR = 2.55, 95 %CI 1.14-5.71). In BKMR analysis, the overall effect of the mixture was significantly associated with ln2-transformed levels of serum total IgE. The cutoff levels for exposure levels related to serum total IgE levels/elevated serum total IgE levels were reported. We discovered that whole-body exposure to 26 chemicals was associated with serum total IgE levels after assessing the findings of these four models. More research is needed in the future to gain a better understanding of the impact of mixed chemical exposure on allergic disorders and how to minimize chemical exposure, especially for people under the age of 18.

Association between prenatal polycyclic aromatic hydrocarbons and infantile allergic diseases modified by maternal glutathione S-transferase polymorphisms: results from the MOCEH birth cohort

Background

Prenatal exposure to polycyclic aromatic hydrocarbons (PAH) has been linked to allergic disease onset. Variations in the glutathione S-transferase (GST) gene family can impact the progression of allergic diseases. We sought to examine the association between prenatal PAH exposure and infantile allergic diseases in 6-month-old infants, and how maternal glutathione S-transferase M1 (GSTM1) or T1 (GSTT1) polymorphism affects the association between prenatal PAH exposure and allergic diseases in the Mothers and Children's Environmental Health (MOCEH) study.

Methods

The study sample comprised 349 infants and their mothers from the MOCEH study, for whom 1-hydroxypyrene (1-OHP) and 2-naphthol were measured in both the early period of pregnancy and late period of pregnancy. An infant was deemed to be affected by an allergic disease if diagnosed with or if developed at least one of the allergic diseases. A logistic regression analysis was performed to study the association between urinary 1-OHP and 2-naphthol levels during pregnancy and allergic diseases in 6-month-old infants. Furthermore, analyses stratified by maternal GSTM1 or GSTT1 present/null polymorphisms were performed.

Results

The risk of allergic diseases in 6-month-old infants was significantly increased in accordance with an increase in urinary 1-OHP during the early period of pregnancy (odds ratio [OR]: 1.84; 95% confidence interval [CI]: 1.05, 3.23; by one log-transformed unit of 1-OHP μg/g creatinine). The increased risk of infantile allergic diseases associated with urinary 1-OHP during the early period of pregnancy was limited to the maternal GSTT1 null type (OR: 2.69; 95% CI: 1.17, 6.21, by one log-transformed unit of 1-OHP μg/g creatinine); however, the Relative Excess Risk due to Interaction was not statistically significant.

Conclusions

The present study found that infantile allergic diseases could be affected by intrauterine PAH exposure, particularly in the early prenatal period and the risk was limited to the maternal GSTT1 null type.

The association between urinary polycyclic aromatic hydrocarbon metabolites and atopic triad by age and body weight in the US population

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are generated during the incomplete combustion of coal/oil/gas and waste. The role of PAH exposure in the atopic triad remains poorly understood. Due to their lipophilic nature, PAHs deposit in adipocytes, potentially placing elderly and those who are overweight at higher risk.

OBJECTIVE

To investigate the association between urinary PAHs and symptoms of atopic triad (chronic pruritus, sneezing, and wheezing).

METHODS

Binary multivariable logistic regression was performed to estimate the association of nine urinary PAHs and atopic diseases followed by subgroup analyses by age (children 6-17, adults 18-49, elderly ≥50 years) and body mass index (BMI) (normal: BMI <25, overweight: BMI ≥ 25 kg/m²) among 2,242 participants of National Health and Nutrition Examination Survey 2005-2006 dataset.

RESULTS

1-hydroxynaphthalene (1-NAP) and hydroxyfluorenes (FLUs) were positively associated with wheezing. When stratified by age, positive associations were found between 1-NAP with wheezing in children/adults and 2-/3-FLU with wheezing in adults/elderly. 3-hydroxyphenanthrene (3-PHE) and 1-hydroxypyrene were positively associated with chronic pruritus in elderly. When stratified by BMI, positive associations were found between 2-PHE with chronic pruritus, 1-NAP and FLUs with wheezing in overweight.

CONCLUSION

Urinary PAH levels were positively associated with atopic triad and this connection was influenced by age and BMI.

Maternal diesel particle exposure promotes offspring asthma through NK cell-derived granzyme B

Mothers living near high-traffic roads before or during pregnancy are more likely to have children with asthma. Mechanisms are unknown. Using a mouse model, here we showed that maternal exposure to diesel exhaust particles (DEP) predisposed offspring to allergic airway disease (AAD, murine counterpart of human asthma) through programming of their NK cells; predisposition to AAD did not develop in DEP pups that lacked NK cells and was induced in normal pups receiving NK cells from WT DEP pups. DEP NK cells expressed GATA3 and cosecreted IL-13 and the killer protease granzyme B in response to allergen challenge. Extracellular granzyme B did not kill, but instead stimulated protease-activated receptor 2 (PAR2) to cooperate with IL-13 in the induction of IL-25 in airway epithelial cells. Through loss-of-function and reconstitution experiments in pups, we showed that NK cells and granzyme B were required for IL-25 induction and activation of the type 2 immune response and that IL-25 mediated NK cell effects on type 2 response and AAD. Finally, experiments using human cord blood and airway epithelial cells suggested that DEP might induce an identical pathway in humans. Collectively, we describe an NK cell-dependent endotype of AAD that emerged in early life as a result of maternal exposure to DEP.

Urinary polycyclic aromatic hydrocarbon metabolites and adult asthma: a case-control study

Polycyclic aromatic hydrocarbons (PAHs) exposure was reported to be associated with childhood asthma. However, the quantitative relationship between PAHs exposure and adult asthma and possible inflammatory pathways are less clear. We aimed to investigate potential associations between urinary PAHs metabolites and adult asthma. We enrolled 507 adult asthma cases and 536 matched controls. The concentrations of 12 urinary PAHs metabolites and plasma cytokines of interleukin (IL)-9 and eotaxin were measured. Potential associations between urinary PAHs metabolites and adult asthma were analyzed by logistic regression. The relationships between urinary PAHs metabolites and plasma cytokines were determined by generalized linear regression. After adjusted for covariates, each 1-unit-increase in natural log-transformed concentrations of 2-hydroxyfluorene (2-OHFLU), 4- hydroxyphenanthrene (4-OHPHE), 1-OHPHE, 2-OHPHE, 1-Hydroxypyrene (1-OHPYR) and ∑OH-PAHs were significantly associated with elevated risk of adult asthma with odds ratios of 2.04, 2.38, 2.04, 1.26, 2.35 and 1.34, respectively. And the associations were more pronounced in the subjects who were female, younger than 45 years, smoker and had history of occupational dust exposure. No associations were observed between urinary PAHs metabolites levels and expressions of IL-9 and eotaxin. Our results demonstrated that elevated urinary PAHs metabolites levels were associated with increased risk of asthma in adults.

Particulate matter properties and health effects: consistency of epidemiological and toxicological studies

Identifying the ambient particulate matter (PM) fractions or constituents, critically involved in eliciting adverse health effects, is crucial to the implementation of more cost-efficient abatement strategies to improve air quality. This review focuses on the importance of different particle properties for PM-induced effects, and whether there is consistency in the results from epidemiological and experimental studies. An evident problem for such comparisons is that epidemiological and experimental data on the effects of specific components of ambient PM are limited. Despite this, some conclusions can be drawn. With respect to the importance of the PM size-fractions, experimental and epidemiological studies are somewhat conflicting, but there seems to be a certain consistency in that the coarse fraction (PM10-2.5) has an effect that should not be neglected. Better exposure characterization may improve the consistency between the results from experimental and epidemiological studies, in particular for ultrafine particles. Experimental data indicate that surface area is an important metric, but composition may play an even greater role in eliciting effects. The consistency between epidemiological and experimental findings for specific PM-components appears most convincing for metals, which seem to be important for the development of both pulmonary and cardiovascular disease. Metals may also be involved in PM-induced allergic sensitization, but the epidemiological evidence for this is scarce. Soluble organic compounds appear to be implicated in PM-induced allergy and cancer, but the data from epidemiological studies are insufficient for any conclusions. The present review suggests that there may be a need for improvements in research designs. In particular, there is a need for better exposure assessments in epidemiological investigations, whereas experimental data would benefit from an improved comparability of studies. Combined experimental and epidemiological investigations may also help answer some of the unresolved issues.

Association of polycyclic aromatic hydrocarbons and asthma among children 6-19 years: NHANES 2001-2008 and NHANES 2011-2012

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemicals that can induce oxidative stress and related cytotoxicity. Whether environmental exposure of PAHs has effects on asthma in the general population is still unclear. This study investigated the association of urinary PAHs with asthma in U.S. children.

METHODS

15 447 children who participated in the US National Health and Nutrition Examination Survey 2001-2008 and 2011-2012 were studied. Ten urinary PAHs were analyzed for their association with asthma or asthma related symptoms. Multivariate logistic regression was applied to assess associations between urinary PAHs and asthma adjusted for age, gender, ethnicity, body mass index and the poverty income ratio.

RESULTS

When stratified by age and sex, we found a remarkable association between urinary 2-phenanthrene and diagnosed asthma in boys (OR: 2.353, 95% CI: 1.156-4.792; P = 0.021) aged 13-19 years old. Positive association was observed between ever wheeze and 4-phenanthrene among girls aged 13-19 years (OR: 4.086, 95% CI: 1.326-12.584, P = 0.043). Moreover, an overall positive association between 1-pyrene and diagnosed asthma was observed. However, no association existed between levels of 1-napthol, 2-napthol, 3-fluorene, 2-fluorene, 3-phenanthrene, 1-phenanthrene or 9-fluorene with asthma or asthma symptom in this population.

CONCLUSIONS

This data provide epidemiological evidences that urinary PAHs are positively associated with asthma in children aged 6-19 years. However, the underlying mechanisms still need further exploration.

Repeatedly high polycyclic aromatic hydrocarbon exposure and cockroach sensitization among inner-city children

BACKGROUND

Exposures to traffic-related air pollutants including polycyclic aromatic hydrocarbons (PAH) have been associated with the development and exacerbation of asthma. However, there is limited evidence on whether these pollutants are associated with the development of cockroach sensitization, a strong risk factor for urban asthma. We hypothesized that repeatedly high PAH exposure during childhood would be associated with increased risk of new cockroach sensitization.

METHODS

As part of the research being conducted by the Columbia Center for Children's Environmental Health (CCCEH) birth cohort study in New York, a spot urine sample was collected from children at age 5 years (2003-2008) and again at age 9-10 years (2008-2012; n=248) and analyzed for 10 PAH metabolites. Repeatedly high PAH (High-High) exposure was defined as measures above median for age 5 PAH metabolites at both time points. Child blood samples at age 5 and 9 years were analyzed for total, anti-cockroach, mouse, dust mite, cat and dog IgE. Relative risks (RR) were estimated with multivariable modified Poisson regression.

RESULTS

Individual PAH metabolite levels, except for 1-naphthol (1-OH-NAP), increased by 10-60% from age 5 to age 9-10. The prevalence of cockroach sensitization increased from 17.6% (33/188) at age 5 to 33.0% (62/188) at 9 years (p=0.001). After controlling for potential covariates including cockroach sensitization at age 5 in regression analyses, positive associations were found between repeatedly high exposure (High-High) to 1-OH-NAP, 3-hydroxyphenanthrene (3-OH-PHEN), or 1-hydroxypyrene (1-OH-PYR) and cockroach sensitization at age 9 (p-values<0.05). Compared to Low-Low exposure, the relative risk (RR) [95% CI] with repeatedly high exposure was 1.83 [1.06-3.17] for 1-OH-NAP, 1.54 [1.06-2.23] for 3-OH-PHEN, and 1.59 [1.04-2.43] for 1-OH-PYR.

CONCLUSIONS

Repeatedly high levels of urinary PAH metabolites during childhood may increase likelihood of sensitization to cockroach allergen in urban inner-city children at age 9 years.

Antihistamine medication may alleviate negative effects of prenatal exposure to polycyclic aromatic hydrocarbons (PAH) on lung function in children. Birth cohort prospective study

The main purpose of the present study was to test the hypothesis that the depressed lung growth attributable to prenatal exposure to polycyclic aromatic hydrocarbons (PAH) may be modified by the intake of antihistamine medications. Individual prenatal PAH exposure was assessed by personal air monitoring in 176 children who were followed over nine years, in the course of which outdoor residential air monitoring, allergic skin tests for indoor allergens, lung function tests (FVC, FEV(1), FEV(05), and FEF(25-75)) were performed. The analysis with the General Estimated Equation (GEE) showed no association between prenatal PAH exposure and lung function in the group of children who were reported to be antihistamine users. However, in the group of antihistamine non-users all lung function tests except for FEF(25-75) were significantly and inversely associated with prenatal airborne PAH exposure. The results of the study suggest that the intake of antihistamine medications in early childhood may inhibit the negative effect of fetal PAH exposure on lung growth and provides additional indirect evidence for the hypothesis that lung alterations in young children resulting from PAH exposure may be caused by the allergic inflammation within lung.

Polycyclic aromatic hydrocarbons and childhood asthma

Asthma is the most common chronic illness in children living in developed countries and the leading cause of childhood hospitalization and school absenteeism. Prevalence rates of asthma are increasing and show disparities across gender, geographic regions, and ethnic/racial groups. Common risk factors for developing childhood asthma include exposure to tobacco smoke, previous allergic reactions, a family history of asthma, allergic rhinitis or eczema, living in an urban environment, obesity and lack of physical exercise, severe lower respiratory tract infections, and male gender. Asthma exacerbation in children can be triggered by a variety of factors, including allergens (e.g., pollen, dust mites, and animal dander), viral and bacterial infections, exercise, and exposure to airway irritants. Recent studies have shown that exposure to polycyclic aromatic hydrocarbons (PAHs), a major component of fine particulate matter from combustion sources, is also associated with onset of asthma, and increasing asthmatic symptoms. In this paper, we review sources of childhood PAH exposure and the association between airborne PAH exposure and childhood asthma prevalence and exacerbation.

Long term effects of prenatal and postnatal airborne PAH exposures on ventilatory lung function of non-asthmatic preadolescent children. Prospective birth cohort study in Krakow

The main goal of the study was to test the hypothesis that prenatal and postnatal exposures to polycyclic aromatic hydrocarbons (PAH) are associated with depressed lung function in non-asthmatic children. The study sample comprises 195 non-asthmatic children of non-smoking mothers, among whom the prenatal PAH exposure was assessed by personal air monitoring in pregnancy. At the age of 3, residential air monitoring was carried out to evaluate the residential PAH exposure indoors and outdoors. At the age of 5 to 8, children were given allergic skin tests for indoor allergens; and between 5 and 9 years lung function testing (FVC, FEV05, FEV1 and FEF25-75) was performed. The effects of prenatal PAH exposure on lung function tests repeated over the follow-up were adjusted in the General Estimated Equation (GEE) model for the relevant covariates. No association between FVC with prenatal PAH exposure was found; however for the FEV1 deficit associated with higher prenatal PAH exposure (above 37 ng/m(3)) amounted to 53 mL (p=0.050) and the deficit of FEF25-75 reached 164 mL (p=0.013). The corresponding deficits related to postnatal residential indoor PAH level (above 42 ng/m(3)) were 59 mL of FEV1 (p=0.028) and 140 mL of FEF25-75 (p=0.031). At the higher residential outdoor PAH level (above 90 ng/m(3)) slightly greater deficit of FEV1 (71 mL, p=0.009) was observed. The results of the study suggest that transplacental exposure to PAH compromises the normal developmental process of respiratory airways and that this effect is compounded by postnatal PAH exposure.

Domestic exposure to volatile organic compounds in relation to asthma and allergy in children and adults

Over the past decades, the prevalence of asthma, allergic disease and atopy has increased significantly and in parallel with the increased use of products and materials emitting volatile organic compounds (VOCs) in the indoor environment. The purpose of this review is to examine the evidence of the relationship between quantitatively measured domestic exposure to VOCs and allergic diseases and allergy in children and adults. Sources, potential immune-inflammatory mechanisms and risks for development and severity of asthma and allergy have been addressed. Available evidence is based on studies that have mainly used observational designs of variable quality. Total, aromatic, aliphatic, microbial VOCs and aldehydes have been the most widely investigated VOC classes, with formaldehyde being the most commonly examined single compound. Overall, the evidence is inadequate to draw any firm conclusions. However, given indicative evidence from a few high-quality studies and significant potential for improvements in asthma outcomes in those with established disease, there is a need to consider undertaking further investigation of the relationship between domestic VOC exposure and asthma/allergy outcomes that should encompass both high-quality, robust observational studies and ultimately clinical trials assessing the impact of interventions that aim to reduce VOC exposure in children and adults with asthma.

A mouse model links asthma susceptibility to prenatal exposure to diesel exhaust

BACKGROUND

Most asthma begins in the first years of life. This early onset cannot be attributed merely to genetic factors because the prevalence of asthma is increasing. Epidemiologic studies have indicated roles for prenatal and early childhood exposures, including exposure to diesel exhaust. However, little is known about the mechanisms. This is largely due to a paucity of animal models.

OBJECTIVE

We aimed to develop a mouse model of asthma susceptibility through prenatal exposure to diesel exhaust.

METHODS

Pregnant C57BL/6 female mice were given repeated intranasal applications of diesel exhaust particles (DEPs) or PBS. Offspring underwent suboptimal immunization and challenge with ovalbumin (OVA) or received PBS. Pups were examined for features of asthma; lung and liver tissues were analyzed for transcription of DEP-regulated genes.

RESULTS

Offspring of mice exposed to DEPs were hypersensitive to OVA, as indicated by airway inflammation and hyperresponsiveness, increased serum OVA-specific IgE levels, and increased pulmonary and systemic TH2 and TH17 cytokine levels. These cytokines were primarily produced by natural killer (NK) cells. Antibody-mediated depletion of NK cells prevented airway inflammation. Asthma susceptibility was associated with increased transcription of genes known to be specifically regulated by the aryl hydrocarbon receptor and oxidative stress. Features of asthma were either marginal or absent in OVA-treated pups of PBS-exposed mice.

CONCLUSION

We created a mouse model that linked maternal exposure to DEPs with asthma susceptibility in offspring. Development of asthma was dependent on NK cells and associated with increased transcription from aryl hydrocarbon receptor- and oxidative stress-regulated genes.

Separate and joint effects of tranplacental and postnatal inhalatory exposure to polycyclic aromatic hydrocarbons: prospective birth cohort study on wheezing events

The goal of this epidemiologic investigation was to analyze the associations between prenatal and postnatal exposure to airborne polycyclic aromatic hydrocarbons (PAH) and severity of wheeze and recurrent wheeze. The 257 children included in this analysis had a complete set of prenatal and postnatal PAH measurements and attended regular health checkups over a 4-year follow-up period since birth. Transplacental PAH exposure was measured by personal air monitoring of the mothers during the second trimester of pregnancy; postnatal exposure was estimated using the same instruments indoors at the children's residences at age 3. Chemical analysis tests were performed to determine airborne concentrations of nine PAH compounds. The results show that both prenatal and postnatal exposure were associated positively with the severity of wheezing days and recurrent wheezing reported in the follow-up. While the incidence rate ratio (IRR) for severity of wheeze and prenatal PAH exposure was 1.53 (95%CI: 1.43-1.64) that for postnatal PAH exposure was 1.13 (95%CI: 1.08-1.19). However, recurrent wheezing was more strongly associated with airborne PAH levels measured at age 3 (OR = 2.31, 95%CI: 1.26-4.22) than transplacental PAH exposure (OR = 1.40, 95% CI: 0.85-2.09), but the difference was statistically insignificant. In conclusion, it appears that prenatal PAH exposure may precipitate and intensify early onset of wheezing symptoms in childhood, resulting from the postnatal exposure and suggest that success in reducing the incidence of respiratory diseases in children would depend on reducing both fetal and childhood exposure to air pollution.

Early-life cockroach allergen and polycyclic aromatic hydrocarbon exposures predict cockroach sensitization among inner-city children

BACKGROUND

Sensitization to cockroach is one of the strongest identified risk factors for greater asthma morbidity in low-income urban communities; however, the timing of exposures relevant to the development of sensitization has not been elucidated fully. Furthermore, exposure to combustion byproducts, including polycyclic aromatic hydrocarbons (PAHs), can augment the development of allergic sensitization.

OBJECTIVE

We sought to test the hypotheses that domestic cockroach allergen measured prenatally would predict cockroach sensitization in early childhood and that this association would be greater for children exposed to higher PAH concentrations.

METHODS

Dominican and African American pregnant women living in New York City were enrolled. In the third trimester expectant mothers wore personal air samplers for measurement of 8 nonvolatile PAHs and the semivolatile PAH pyrene, and dust was collected from homes for allergen measurement. Glutathione-S-transferase μ 1 (GSTM1) gene polymorphisms were measured in children. Allergen-specific IgE levels were measured from the children at ages 2, 3, 5, and 7 years.

RESULTS

Bla g 2 in prenatal kitchen dust predicted cockroach sensitization at the ages of 5 to 7 years (adjusted relative risk [RR], 1.15; P = .001; n = 349). The association was observed only among children with greater than (RR, 1.22; P = .001) but not less than (RR, 1.07; P = .24) the median sum of 8 nonvolatile PAH levels. The association was most pronounced among children with higher PAH levels and null for the GSTM1 gene (RR, 1.54; P = .001).

CONCLUSIONS

Prenatal exposure to cockroach allergen was associated with a greater risk of allergic sensitization. This risk was increased by exposure to nonvolatile PAHs, with children null for the GSTM1 mutation particularly vulnerable.

Polycyclic aromatic hydrocarbon exposure and pediatric asthma in children: a case-control study

BACKGROUND

Bronchial asthma is one of the most prevalent diseases in Arab children. Environmental pollution has been suggested to be considered causative of asthma, nasal symptoms and bronchitis in both children and adult. The objectives of this study were to evaluate the association between serum polycyclic aromatic hydrocarbons (PAHs) levels, asthma and allergic outcomes among Saudi children aged up to 15 yrs. We hypothesized that increased serum PAHs are associated with allergy, asthma, or respiratory symptoms.

METHODS

A total of 195 Saudi children (98 asthma pediatric patients and 97 healthy controls) were randomly selected from the Riyadh Cohort Study for inclusion. The diagnosis of Asthma was based on established pediatric diagnosis and medications taken.

RESULTS

Asthma related markers showed highly significant differences between children with and without asthma. Thus IgE, resistin and IL-4 were significantly increased (p 0.004, 0.001 and 0.003, respectively) in children with asthma compared with non-asthma control subjects. GMCSF, IFN-γ, IL-5, IL-8 and IL-10, on the other hand, were significantly decreased in children with asthma (p 0.003, 0.03, 0.001, 0.004 and 0.03, respectively). Strong associations between serum PAHs levels and biomarkers of childhood asthma were detected in Arabic children. Data confirmed the role of naphthalene, 4H-cyclobenta[def]phenanthrene, 1,2-benzanthracene, chrysene and benzo(e)acephenanthrylene in childhood asthma; levels of these PAHs were correlated with asthma related biomarkers including IgE, resistin, GMCSF and IFN-γ as well as IL-4, IL-5, IL-8 and IL-10 cytokines.

CONCLUSIONS

This data highlight the pivotal role of specific PAHs in childhood asthma.

Repeated exposure to polycyclic aromatic hydrocarbons and asthma: effect of seroatopy

BACKGROUND

Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAHs), can induce asthma. However, the effects of early repeated PAH exposure over time on different asthma phenotypes have not been examined.

OBJECTIVE

To assess associations between repeated PAH exposure, measured from prenatal personal and residential indoor monitors in children's homes, and asthma in an inner-city cohort.

METHODS

Prenatal exposure was assessed by personal air monitoring during 48 hours and exposure at 5 to 6 years of age by 2-week residential monitoring in the Columbia Center for Children's Environmental Health cohort. PAH was dichotomized into pyrene (representative semivolatile PAH) and the sum of 8 nonvolatile PAHs. High exposure to each was defined as measures above the median at both repeated time points. Asthma and wheeze were determined by validated questionnaires at ages 5 to 6 years. Children with specific IgE levels greater than 0.35 IU/mL to any of 5 indoor allergens were considered seroatopic.

RESULTS

Among all 354 children, repeated high exposure to pyrene was associated with asthma (odds ratio [OR], 1.90; 95% confidence interval [CI], 1.13-3.20). Among 242 nonatopic children, but not those sensitized to indoor allergens (n = 87) or with elevated total IgE levels (n = 171), high pyrene levels were associated positively with asthma (OR, 2.89; 95% CI, 1.77-5.69), asthma medication use (OR, 2.28; 95% CI, 1.13-4.59), and emergency department visits for asthma (OR, 2.43; 95% CI, 1.20-4.91). Associations between the levels of the 8 nonvolatile PAHs and asthma were not observed, even when stratifying by seroatopy.

CONCLUSION

Nonatopic children may be more susceptible to the respiratory consequences of early pyrene exposures.

Biology of diesel exhaust effects on allergic pulmonary inflammation

Although the adverse health effects of diesel exhaust particles (DEP) have been proposed and are being clarified, their facilitating effects on preexisting pathological conditions (pathological conditions) have not been fully identified. On the other hand, there exist hypersensitive subjects against particulate matters. In this review, we provide insights into the immunotoxicity of DEP as an aggravating factor in hypersusceptible subjects, especially those with allergic pulmonary diseases using our in vivo experimental model. In brief, we examined the effects of DEP on allergic asthma in vivo, and showed that repetitive pulmonary exposure to DEP has promoting effects on allergic airway inflammation, including adjuvanticity on Th2-milieu. Further, we propose a causal machinery regarding the adverse impacts, i.e., via inappropriate activation of antigen-presenting cells such as dendritic cells.

Prenatal exposure to polycyclic aromatic hydrocarbons, environmental tobacco smoke and asthma

BACKGROUND

Previously, we reported that prenatal exposures to polycyclic aromatic hydrocarbons (PAH) and postnatal environmental tobacco smoke (ETS) in combination were associated with respiratory symptoms at ages 1 and 2 years. Here, we hypothesized that children exposed to both prenatal PAH and ETS may be at greater risk of asthma and seroatopy at ages 5-6 years, after controlling for current pollution exposure.

METHODS

Prenatal PAH exposure was measured by personal air monitoring over 48 h. ETS exposure, respiratory symptoms and asthma at ages 5-6 years were assessed through questionnaire. Immunoglobulin (Ig) E was measured by Immunocap.

RESULTS

A significant interaction between prenatal PAH and prenatal (but not postnatal) ETS exposure on asthma (p < 0.05), but not IgE, was detected. Among children exposed to prenatal ETS, a positive nonsignificant association was found between prenatal PAH exposure and asthma (OR 1.96, 95% CI [0.95-4.05]). Among children without exposure to prenatal ETS, a negative nonsignificant association was found between prenatal PAH exposure and asthma (OR 0.65, 95% CI [0.41-1.01]). Prenatal PAH exposure was not associated with asthma or IgE at age 5-6 years.

CONCLUSIONS

Combined prenatal exposure to PAH and ETS appears to be associated with asthma but not seroatopy at age 5-6. Exposure to PAH alone does not appear associated with either asthma or seroatopy at age 5-6 years. Discerning the differential effects between ETS exposed and ETS nonexposed children requires further study.

Nitration of the egg-allergen ovalbumin enhances protein allergenicity but reduces the risk for oral sensitization in a murine model of food allergy

BACKGROUND

Nitration of proteins on tyrosine residues, which can occur due to polluted air under "summer smog" conditions, has been shown to increase the allergic potential of allergens. Since nitration of tyrosine residues is also observed during inflammatory responses, this modification could directly influence protein immunogenicity and might therefore contribute to food allergy induction. In the current study we have analyzed the impact of protein nitration on sensitization via the oral route.

METHODOLOGY/PRINCIPAL FINDINGS

BALB/c mice were immunized intragastrically by feeding untreated ovalbumin (OVA), sham-nitrated ovalbumin (snOVA) or nitrated ovalbumin (nOVA) with or without concomitant acid-suppression. To analyze the impact of the sensitization route, the allergens were also injected intraperitoneally. Animals being fed OVA or snOVA under acid-suppressive medication developed significantly elevated levels of IgE, and increased titers of specific IgG1 and IgG2a antibodies. Interestingly, oral immunizations of nOVA under anti-acid treatment did not result in IgG and IgE formation. In contrast, intraperitoneal immunization induced high levels of OVA specific IgE, which were significantly increased in the group that received nOVA by injection. Furthermore, nOVA triggered significantly enhanced mediator release from RBL cells passively sensitized with sera from allergic mice. Gastric digestion experiments demonstrated protein nitration to interfere with protein stability as nOVA was easily degraded, whereas OVA and snOVA remained stable up to 120 min. Additionally, HPLC-chip-MS/MS analysis showed that one tyrosine residue (Y(107)) being very efficiently nitrated is part of an ovalbumin epitope recognized exclusively after oral sensitization.

CONCLUSIONS/SIGNIFICANCE

These data indicated that despite the enhanced triggering capacity in existing allergy, nitration of OVA may be associated with a reduced de novo sensitizing capability via the oral route due to enhanced protein digestibility and/or changes in antibody epitopes.

Intrauterine exposure to polycyclic aromatic hydrocarbons, fine particulate matter and early wheeze. Prospective birth cohort study in 4-year olds

The main goal of the study was to determine the relationship between prenatal exposure to polycyclic aromatic hydrocarbons (PAHs) measured by PAH-DNA adducts in umbilical cord blood and early wheeze. The level of PAH-DNA adducts in the cord blood is assumed to reflect the cumulative dose of PAHs absorbed by the foetus over the prenatal period. The effect of prenatal PAH exposure on respiratory health measured by the incidence rate ratio (IRR) for the number of wheezing days in the subsequent 4 yr follow-up was adjusted for potential confounding factors such as personal prenatal exposure to fine particulate matter (PM(2.5)), environmental tobacco smoke (ETS), gender of child, maternal characteristics (age, education and atopy), parity and mould/dampness in the home. The study sample includes 339 newborns of non-smoking mothers 18-35 yr of age and free from chronic diseases, who were recruited from ambulatory prenatal clinics in the first or second trimester of pregnancy. The number of wheezing days during the first 2 yr of life was positively associated with prenatal level of PAH-DNA adducts (IRR = 1.69, 95%CI = 1.52-1.88), prenatal particulate matter (PM(2.5)) level dichotomized by the median (IRR = 1.38; 95%CI: 1.25-1.51), maternal atopy (IRR = 1.43; 95%CI: 1.29-1.58), mouldy/damp house (IRR = 1.43; 95%CI: 1.27-1.61). The level of maternal education and maternal age at delivery was inversely associated with the IRRs for wheeze. The significant association between frequency of wheeze and the level of prenatal environmental hazards (PAHs and PM(2.5)) was not observed at ages 3 or 4 yrs. Although the frequency of wheezing at ages 3 or 4 was no longer associated with prenatal exposure to PAHs and PM(2.5), its occurrence depended on the presence of wheezing in the first 2 yr of life, which nearly tripled the risk of wheezing in later life. In conclusion, the findings may suggest that driving force for early wheezing (<24 months of age) is different to those leading to later onset of wheeze. As we reported no synergistic effects between prenatal PAH (measured by PAH-DNA adducts) and PM(2.5) exposures on early wheeze, this suggests the two exposures may exert independent effects via different biological mechanism on wheeze.

Polycyclic aromatic hydrocarbon metabolite levels and pediatric allergy and asthma in an inner-city cohort

Exposure to polycyclic aromatic hydrocarbons (PAH) has been associated with allergic sensitization and asthma. We hypothesized that increased urinary PAH metabolites are associated with allergy or asthma among children age 5 yrs in an inner-city birth cohort. As part of an ongoing prospective birth cohort under the auspices of the Columbia Center for Children's Environmental Health (CCCEH), urine was collected from 5-yr-old children (n = 222) of Dominican American and African American mothers in Northern Manhattan and South Bronx of New York City. Twenty-four PAH metabolites were measured in these specimens, and their levels (unadjusted and specific gravity corrected) were evaluated with IgE levels and asthma outcomes. Ten metabolites were detected in urine from all children. Concentrations ranged higher than those in representative samples of US children ages 6-11 in the National Health and Nutrition Examination Survey (NHANES). Among CCCEH children, compared with African Americans, the Dominican children had higher 2-hydroxynaphthalene but lower 9-hydroxyfluorene and 4-hydroxyphenanthrene concentrations. Increased 3-hydroxyfluorene and 3-hydroxyphenanthrene levels were associated with higher anti-mouse IgE levels (p < 0.05). These plus 2-hydroxynaphthalene, 2-hydroxyflourene and 1-hydroxyphenanthrene concentrations were associated with higher anti-mouse IgE levels on multivariate analyzes. Increased 2-hydroxyphenanthrene, 3-hydroxyphenanthrene and 4-hydroxyphenanthrene levels were associated with higher anti-cat IgE levels (p < 0.05) in univariate, but not multivariate, analyzes. Levels of PAH metabolites were not associated with respiratory symptoms. Measures of PAH metabolites suggest considerable exposure in an urban pediatric population, and possible associations with allergic sensitization to mouse.

Effect of diesel exhaust particles on house dust mite-induced airway eosinophilic inflammation and remodeling in mice

Recent research has focused on the effects of ambient particulate pollution and much evidence has indicated that particulate pollution is associated with the onset of asthma and allergy; however, the effect of diesel exhaust particles (DEP) on the development of allergen-induced airway remodeling has not been fully investigated in vivo. In the present study, we examined the effects of DEP on Dermatophagoides farinae allergens (Der f)-induced asthma-like phenotypes in mice. Mice were administered i.t. 8 times with Der f. DEP were injected i.t. with Der f 4 times throughout the experiment or twice at the sensitization period. In both cases, DEP aggravated Der f-induced increases in airway responsiveness to acetylcholine, the number of eosinophils and neutrophils in the bronchoalveolar lavage fluid (BALF), serum Der f-specific IgG1 levels, Th2 cytokines and transforming growth factor-beta1 levels in BALF, and amount of hydroxyproline in the right lungs. Furthermore, goblet cell hyperplasia and subepithelial fibrosis were also markedly aggravated. These findings indicate that DEP can potentiate airway remodeling induced by repeated allergen challenge as well as Th2-drived airway hyperresponsiveness, eosinophilic inflammation, and IgG1 production and that DEP can exhibit adjuvant activity for airway remodeling, probably due to the enhancement of allergen sensitization and/or of Th2 polarizing pathways.

Immunotoxicologic analysis of maternal transmission of asthma risk

Asthma has origins in early life. Epidemiological studies show that maternal, more than paternal, asthma significantly increases a child's risk of developing the disease. Experimental animal models exist which reproduce the increased susceptibility to asthma seen in human studies, and allow analysis of immunotoxic mechanisms that may contribute to neonatal allergy. In addition to maternal asthma, chemically-induced skin contact hypersensitivity or exposure during pregnancy of non-allergic females to certain environmental agents, e.g., air pollution particles, can also result in increased susceptibility to asthma in their offspring. We review here experimental models of maternal transmission of asthma risk, the progress to date in identifying mechanisms, and potential directions for future research.

Effects of Diesel Exhaust Particles on Antigen-Presenting Cells and Antigen-Specific Th Immunity in Mice

Diesel exhaust particles (DEP) exacerbate antigen-related airway inflammation and hyperresponsiveness in mice; however, the mechanisms remain undefined. The present study characterized more precisely which pathways and cellular events of the allergic response are amplified by DEP in view of the maturation/activation/function of antigen-presenting cells (APC) and the antigen-specific Th response. We evaluated the effects of DEP on the phenotype and function of bone marrow-derived dendritic cells (BMDC) in vitro and on the expression pattern of APC-related molecules in the murine lung in the presence or absence of antigen in vivo. Also, we tested the effects of in vivo DEP co-exposure with antigen on the splenic antigen-specific Th response in the context of cytokine production. DEP significantly increased both allogeneic and antigen (ovalbumin: OVA)-specific syngeneic T-cell proliferation in vitro. In addition, an in vivo experiment showed that repetitive pulmonary exposure to DEP plus antigen (OVA) increased the numbers of MHC class II+cells and those expressing CD11c, DEC205 (DC markers), CD80, CD86 (co-stimulatory molecules), F4/80 (a macrophage marker), and CD19 (a B-cell differentiation antigen) in the lung as compared to that of others (vehicle, DEP, or OVA). Furthermore, an ex vivo assay system demonstrated that splenic mononuclear cells primed by DEP plus OVA produced a greater amount of interleukin (IL)-4, IL-5, and IL-13 after in vitro antigen stimulation compared to those primed by the other treatments. In conclusion, enhancement of allergic responses by DEP can be explained via two novel mechanisms, i.e., enhancement effects on APC including DC and on antigen-specific Th response, which culminate in the promotion of local and systemic dysregulated Th immunity.

Exposure to Bisphenol A prenatally or in adulthood promotes T(H)2 cytokine production associated with reduction of CD4CD25 regulatory T cells

BACKGROUND

Bisphenol A (BPA) is a widespread endocrine-disrupting chemical that can affect humans and animals.

OBJECTIVES

We investigated the effects of adult or prenatal exposure to BPA on T-helper (T(H))1/T(H)2 immune responses and the mechanisms underlying these effects.

METHODS

To evaluate the effects of exposure to BPA in adulthood, male Leishmania major-susceptible BALB/c and -resistant C57BL/6 mice were subcutaneously injected with 0.625, 1.25, 2.5, and 5 micromol BPA 1 week before being infected with L. major. To evaluate prenatal exposure, female mice were given BPA-containing drinking water at concentrations of 1, 10, and 100 nM for 2 weeks, then mated, and given BPA for another week. Male 10-week-old offspring were infected with L. major. Footpad swelling was assessed as a measure of the course of infection.

RESULTS

Mice exposed to BPA prenatally or in adulthood showed a dose-dependent increase in footpad swelling after being infected with L. major. Exposure to BPA in adulthood significantly promoted antigen-stimulated production of interleukin (IL)-4, IL-10, and IL-13 but not interferon-gamma (IFN-gamma). However, mice prenatally exposed to BPA showed increased production of not only IL-4 but also IFN-gamma. The percentages of CD4(+)CD25(+) cells were decreased in mice exposed to BPA either prenatally or in adulthood. Effects of prenatal BPA exposure were far more pronounced than effects of exposure in adulthood.

CONCLUSION

BPA promotes the development of T(H)2 cells in adulthood and both T(H)1 and T(H)2 cells in prenatal stages by reducing the number of regulatory T cells.

Combined inhaled diesel exhaust particles and allergen exposure alter methylation of T helper genes and IgE production in vivo

Changes in methylation of CpG sites at the interleukin (IL)-4 and interferon (IFN)-gamma promoters are associated with T helper (Th) 2 polarization in vitro. No previous studies have examined whether air pollution or allergen exposure alters methylation of these two genes in vivo. We hypothesized that diesel exhaust particles (DEP) would induce hypermethylation of the IFN-gamma promoter and hypomethylation of IL-4 in CD4+ T cells among mice sensitized to the fungus allergen Aspergillus fumigatus. We also hypothesized that DEP-induced methylation changes would affect immunoglobulin (Ig) E regulation. BALB/c mice were exposed to a 3-week course of inhaled DEP exposure while undergoing intranasal sensitization to A. fumigatus. Purified DNA from splenic CD4+ cells underwent bisulfite treatment, PCR amplification, and pyrosequencing. Sera IgE levels were compared with methylation levels at several CpG sites in the IL-4 and IFN-gamma promoter. Total IgE production was increased following intranasal sensitization A. fumigatus. IgE production was augmented further following combined exposure to A. fumigatus and DEP exposure. Inhaled DEP exposure and intranasal A. fumigatus induced hypermethylation at CpG(-45), CpG(-53), CpG(-205) sites of the IFN-gamma promoter and hypomethylation at CpG(-408) of the IL-4 promoter. Altered methylation of promoters of both genes was correlated significantly with changes in IgE levels. This study is the first to demonstrate that inhaled environmental exposures influence methylation of Th genes in vivo, supporting a new paradigm in asthma pathogenesis.

Environmental polycyclic aromatic hydrocarbons (PAHs) enhance allergic inflammation by acting on human basophils

Diesel exhaust particles (DEPs) have been implicated in the worldwide increased incidence of allergic airway diseases over the past century. There is growing evidence that DEP-associated polycyclic aromatic hydrocarbons (PAHs) participate in the development and maintenance of immunoglobulin (Ig) E-mediated allergic diseases. To address this issue we investigated the impact of U.S. Environmental Protection Agency (EPA) priority PAHs as well as of PAH-containing airborne extracts on antigen-induced CD63 upregulation and mediator release from human basophils. Whole blood samples from birch pollen allergic and control subjects were incubated in the presence of organic extracts of urban aerosol (AERex) or EPA-PAH standard with or without rBet v 1. Basophils were analyzed for CD63 expression as a measure of basophil activation by using multiparameter flow cytometry. In addition, purified basophils from birch pollen allergic donors were incubated for 2 h in the presence of 1 muM benzo[a]pyrene (BaP) or phenanthrene (Phe) and then stimulated with rBet v 1 for 45 min. Supernatants were assayed for histamine, interleukin (IL)-4, and IL-8 by means of enzyme-linked immunosorbent assay (ELISA). Basophils exposed in vitro simultaneously to AERex or EPA-PAH standard and rBet v 1 expressed CD63 significantly more than with antigen alone. PAHs synergized with rBet v 1 dose dependently, but did not activate basophils from nonallergic donors. BaP and Phe significantly enhanced cytokine secretion (IL-4, IL-8) and histamine release from purified basophils without antigen added, and secretion was not further enhanced by rBet v 1 stimulation. In conclusion, PAHs from roadside emissions can directly activate sensitized basophils to cytokine secretion and drive proallergic processes through enhanced Fcepsilon RI-coupled mediator release from human basophils.

Pulmonary exposure to particles during pregnancy causes increased neonatal asthma susceptibility

Maternal immune responses can promote allergy development in offspring, as shown in a model of increased susceptibility to asthma in babies of ovalbumin (OVA)-sensitized and -challenged mother mice. We investigated whether inflammatory responses to air pollution particles (diesel exhaust particles, DEP) or control "inert" titanium dioxide (TiO(2)) particles are enhanced during pregnancy and whether exposure to particles can cause increased neonatal susceptibility to asthma. Pregnant BALB/c mice (or nonpregnant controls) received particle suspensions intranasally at Day 14 of pregnancy. Lung inflammatory responses were evaluated 48 hours after exposure. Offspring of particle- or buffer-treated mothers were sensitized and aerosolized with OVA, followed by assays of airway hyperresponsiveness (AHR) and allergic inflammation (AI). Nonpregnant females had the expected minimal response to "inert" TiO(2). In contrast, pregnant mice showed robust and persistent acute inflammation after both TiO(2) and DEP. Genomic profiling identified genes differentially expressed in pregnant lungs exposed to TiO(2). Neonates of mothers exposed to TiO(2) (and DEP, but not PBS) developed AHR and AI, indicating that pregnancy exposure to both "inert" TiO(2) and DEP caused increased asthma susceptibility in offspring. We conclude that (1) pregnancy enhances lung inflammatory responses to otherwise relatively innocuous inert particles; and (2) exposures of nonallergic pregnant females to inert or toxic environmental air particles can cause increased allergic susceptibility in offspring.

Exposure of pregnant mice to an air pollutant aerosol increases asthma susceptibility in offspring

Air pollution contributes to both exacerbation and development of bronchial asthma. Studies showed that coexposure to air pollution directly promotes sensitization to inhaled allergen in neonatal mice. The aim of this study was to investigate whether prenatal exposure to air pollution could also increase susceptibility to development of asthma in early life. Pregnant female BALB/c mice were exposed to aerosolized leachate of residual oil fly ash (ROFA, 50 mg/ml, 30 min) at 5, 3, and 1 d before delivery. Offspring were treated once at 3 d of age with ovalbumin (OVA, 5 mug) and alum (ip), an intentionally suboptimal dose for sensitization, exposed to aerosolized OVA (1%, 10 min) at 12-14 d or 32-35 d of age, and evaluated 2 d after the final exposure. The offspring of ROFA-exposed mothers (ROFA group) revealed increasing airway hyperresponsiveness (higher enhanced pause [Penh] to methacholine challenge) and elevated substantial numbers of eosinophils in the bronchoalveolar lavage flued (BALF). Histopathology revealed prominent inflammation in the lungs of ROFA group and showed increased allergen-specific IgE and IgG1 levels. Their cultured splenocytes showed an enhanced interleukin (IL)-4/interferon (IFN)-gamma cytokine, indicating Th2 skewed immunity. Data indicate that exposure of pregnant female mice to an air pollutant aerosol increased asthma susceptibility in their offspring.

Nitration Enhances the Allergenic Potential of Proteins

BACKGROUND

Recent investigations have shown that proteins, including Bet v 1a, are nitrated by exposure to polluted urban air. We have investigated immunogenic and allergenic properties of in vitro nitrated allergens in in vivo models.

METHODS

Untreated and nitrated samples of ovalbumin or Bet v 1a were compared for their ability to stimulate proliferation and cytokine secretion in splenocytes from DO11.10 or from sensitized BALB/c mice, and for their ability to induce specific immunoglobulin (Ig)G1, IgG2a and IgE in sensitized mice. Additionally, sera from birch pollen-allergic individuals were analysed for IgE and IgG specific for nitrated Bet v 1a.

RESULTS

Upon splenocyte stimulation with nitrated as compared with unmodified allergens, proliferation as well as interleukin 5 and interferon-gamma production were enhanced. Sera of mice sensitized with nitrated allergens showed elevated levels of specific IgE, IgG1 and IgG2a, compared with sera from mice sensitized with unmodified allergens. Moreover, cross-reactivity of antibodies against unrelated, nitrated allergens was observed in mice. We also found higher amounts of functional, specific IgE against nitrated than against untreated Bet v 1a in sera from birch pollen-allergic patients.

CONCLUSIONS

Our findings suggest that nitration enhances allergic responses, which may contribute to an increased prevalence of allergic diseases in polluted urban environments.

Organic extracts of urban aerosol (< or =PM2.5) enhance rBet v 1-induced upregulation of CD63 in basophils from birch pollen-allergic individuals

Epidemiological studies have linked the high prevalence rates of IgE-mediated allergic diseases to an increase in exposure to traffic-related air pollutants such as diesel exhaust particles (DEPs). There is growing experimental evidence that organic compounds of DEPs, predominantly polycyclic aromatic hydrocarbons (PAHs), participate in the development and maintenance of allergic airway diseases. In this study we investigated the impact of organic extracts of urban aerosol (AERex) containing various PAH concentrations on the activation of human basophils. Whole blood samples from six birch pollen-allergic and five control subjects were repeatedly incubated in the presence of AERex with or without recombinant Bet v 1 (rBet v 1). Basophils were analyzed for CD63 expression as a measure of basophil activation by using multiparameter flow cytometry. Basophils, when exposed in vitro to AERex and rBet v 1, expressed CD63 significantly more than with antigen activation alone. AERex synergized with rBet v 1 in a dose-dependent manner, but did not activate basophils from nonallergic donors. AERex effect on CD63 upregulation was found in blood samples of all patients and did not occur in the absence of rBet v 1. Strongest basophil activation was monitored upon stimulation with AERex comprising the highest PAH content. The capability of AERex to increase activation of basophils from birch pollen-allergic subjects at ambient concentrations suggests an important role of organic compounds of airborne particles in the aggravation of IgE-mediated allergic diseases. This could be a new aspect of regulation of unspecific promoting stimuli in clinical manifestation of allergic inflammation.

Role of the Nrf2-mediated signaling pathway as a negative regulator of inflammation: implications for the impact of particulate pollutants on asthma

Particulate matter (PM) is an environmental factor that may contribute to the exacerbation and possibly the development of asthma. PM contain redox-active chemicals and transition metals which generate reactive oxygen species (ROS). Excessive ROS can induce oxidative stress, which proceeds in hierarchical fashion to generate cellular responses. The most sensitive cellular response to mild oxidative stress is the activation of antioxidant and phase II enzymes (tier 1). If this protection fails, further increase of oxidative stress can induce inflammation (tier 2) and cell death (tier 3). Tier 1 antioxidant defenses are critical for protecting against airway inflammation and asthma. The expression of these antioxidant enzymes is regulated by the transcription factor, Nrf2. In response to oxidative stress, Nrf2 escapes from Keap1-mediated proteasomal degradation resulting in prolonged protein half-life and its nuclear accumulation. Nrf2 interacts with the antioxidant response element (ARE) in the promoters of phase II enzyme genes, leading to their transcriptional activation. Several phase II expression polymorphisms are associated with an increased risk of asthma. The indispensable role of Nrf2 in tier-1 oxidative stress response suggests that polymorphisms of Nrf2-regulated genes may be useful susceptibility markers for asthma. Moreover, chemopreventive Nrf2 inducers may be used for treating PM-exacerbated asthma.

Ambient air particles from four European cities increase the primary cellular response to allergen in the draining lymph node

In the RAIAP (respiratory allergy and inflammation due to ambient particles) project, qualitative properties of ambient air particles from Amsterdam, Oslo, Lodz and Rome were investigated in relation to inflammation and allergy. Most collected particle fractions were found to increase the allergen-specific IgE and IgG2a responses after subcutaneous injection of particles with allergen in mice. However, some fractions appeared to skew the antibody response towards more Th1- or Th2-associated antibody isotypes, and the fine fractions were found to be more potent than the coarse fractions with regard to IgE adjuvant activity. In the present study we investigated the cellular response in the draining lymph node 5 days after a subcutaneous injection of selected RAIAP particle fractions. The particles (100 microg) were injected into both hind footpads of BALB/cA mice, in the presence or absence of the allergen ovalbumin (OVA, 50 microg). We also studied if the coarse and fine RAIAP particle fractions affected the cellular responses to OVA differently. The number of lymph node cells, as well as the relative number of B and T lymphocytes and T helper cells were determined. Expression of cell surface molecules (MHC class II, CD86 and CD23) and ex vivo cytokine production (IL-4, IL-10 and IFN-gamma) by the lymph node cells were measured. Overall, particles in the presence of allergen enhanced the levels of the various cellular parameters compared to allergen alone or particles alone. In the absence of allergen, ambient air particles, in contrast to diesel exhaust particles, marginally affected some cellular parameters. By histological examination of the lymph node, the particles appeared to be scattered between the lymphocytes, often localised within macrophage-like (acid phosphatase positive) cells. The cell parameters measured could, for the individual sample, neither predict the degree of a Th2- or Th1-skewed antibody response, nor the stronger antibody adjuvant capacity of the fine than the coarse particle fractions. In conclusion, we have shown that coarse and fine ambient air particles from different European cities enhance the cellular response in the draining lymph node after injection with an allergen. In the absence of allergen, ambient particles only marginally affected the cellular parameters.

Polycyclic aromatic hydrocarbons, environmental tobacco smoke, and respiratory symptoms in an inner-city birth cohort

STUDY OBJECTIVES

Several studies have found associations between diesel exposure, respiratory symptoms, and/or impaired pulmonary function. We hypothesized that prenatal exposure to airborne polycyclic aromatic hydrocarbons (PAH), important components of diesel exhaust and other combustion sources, may be associated with respiratory symptoms in young children. We also hypothesized that exposure to environmental tobacco smoke (ETS) may worsen symptoms beyond that observed to be associated with PAH alone.

DESIGN/PARTICIPANTS

To test our hypotheses, we recruited 303 pregnant women from northern Manhattan believed to be at high risk for exposure to both PAH and ETS, collected 48-h personal PAH exposure measurements, and monitored their children prospectively.

RESULTS

By 12 months of age, more cough and wheeze were reported in children exposed to prenatal PAH in concert with ETS postnatally (PAH x ETS interaction odds ratios [ORs], 1.41 [p < 0.01] and 1.29 [p < 0.05], respectively). By 24 months, difficulty breathing and probable asthma were reported more frequently among children exposed to prenatal PAH and ETS postnatally (PAH x ETS ORs, 1.54 and 1.64, respectively [p < 0.05]).

CONCLUSIONS

Our results suggest that early exposure to airborne PAH and ETS can lead to increased respiratory symptoms and probable asthma by age 12 to 24 months. Interventions to lower the risk of respiratory disease in young children living in the inner city may need to address the importance of multiple environmental exposures.

Enhancement of Interleukin-4 Production in Activated CD4+ T Cells by Diphthalate Plasticizers via Increased NF-AT Binding Activity

BACKGROUND

Diethylhexyl phthalate (DEHP) and diisononyl phthalate (DINP), two commonly used plasticizers in flexible polyvinylchloride formulations, have potentially adverse effects on human health. However, the influence of these diphthalates on allergic responses remains unclear. In this study we examined the effects of DEHP and DINP on IL-4 production in CD4+ T cells and the level of IgE in sera, critical hallmarks associated with allergic diseases.

METHODS

Mouse T cells were exposed to two diphthalates in vitro and in vivo. The levels of IL-4 and IgE were determined by ELISA, and the degree of NF-AT activation was determined by IL-4 gene promoter assay and electrophoretic mobility shift assay.

RESULTS AND DISCUSSION

Both DEHP and DINP significantly enhanced IL-4 production in activated CD4+ T cells in a concentration-dependent manner. Treatment with DEHP or DINP in vivo resulted in a significant increase of IL-4 production in CD4+ T cells and of IgE levels in sera. Furthermore, DEHP and DINP enhanced the activation of IL-4 gene promoter in EL4 T cells and the enhancing effect mapped to a region in the IL-4 promoter containing binding sites for a transcription factor, NF-AT. The activation of T cells resulted in markedly enhanced binding activities to the NF-AT site, which significantly increased upon addition of DEHP or DINP, indicating that NF-AT was involved in the enhancing effect of DEHP and DINP on IL-4 production. These findings suggest that both DEHP and DINP enhance allergic responses by enhancement of IL-4 production in CD4+ T cells via stimulation of NF-AT-binding activity.

Exposure to 4-tert-octylphenol, an environmentally persistent alkylphenol, enhances interleukin-4 production in T cells via NF-AT activation

4-tert-Octylphenol (OP) is a representative endocrine disruptor that may have adverse effects on human health. The influence of this compound on allergic immune responses remains unclear. In this study, we have examined the effects of OP on production of interleukin-4 (IL-4), a pro-inflammatory cytokine closely associated with allergic immune responses. OP significantly enhanced IL-4 production in antigen-primed T cells in a dose-dependent manner. Treatment with OP in vivo resulted in significant increase of IL-4 production in T cells and of IgE levels in sera of antigen-primed mice. Furthermore, OP enhanced the activation of IL-4 gene promoter in EL4 T cells transiently transfected with IL-4 promoter/reporter constructs, and the enhancing effect mapped to a region in the IL-4 promoter containing binding sites for nuclear factor of activated T cell (NF-AT). Activation of T cells by phorbol-12-myristate-13-acetate (PMA) resulted in markedly enhanced binding activities to the NF-AT site, which significantly increased upon addition of OP, indicating that the transcription factor NF-AT was involved in the enhancing effect of OP on IL-4 production. The enhancement of IL-4 production by OP was blocked by FK506, a calcineurin inhibitor, but not by the estrogen receptor (ER) antagonist ICI 182780. FK506 inhibited the NF-AT-DNA binding activity and IL-4 gene promoter activity enhanced by OP in a dose-dependent manner. These findings demonstrate that OP enhances IL-4 production in T cells via the stimulation of calcineurin-dependent NF-AT activation.

The diesel exhaust component pyrene induces expression of IL-8 but not of eotaxin

Environmental pollutants can influence the expression of immunoregulatory molecules and, in this way, promote allergies. The local synthesis of proinflammatory chemokines is an important aspect in the development of allergic airway inflammation. We have characterized the influence of pyrene, a polycyclic aromatic hydrocarbon (PAH) contained, for example, in diesel exhaust particles (DEP), on transcription and secretion of the chemokines interleukin-8 (IL-8) and eotaxin. Reporter genes under control of the respective promoters were tested in the human cell lines A549 and HeLa, mRNA production was assayed in A549 cells and protein production was measured by ELISA in cell supernatants from primary human fibroblasts. Pyrene content of cell supernatants was measured by analytical HPLC. Promoter activity, mRNA production and protein expression of IL-8 were increased by pyrene. The activating effect in reporter gene studies was abolished by mutating either an NF-kappaB or an AP-1 binding site in the IL-8 promoter. In contrast, pyrene showed no effect on transcription from the eotaxin promoter, despite the important role of this chemokine in asthma. Our data show that pyrene has specific effects on chemokine synthesis, which are not restricted to mediators primarily associated with atopic diseases. Pyrene also affected cells not derived from lung tissue, which suggests a broader immunoregulatory influence for this pollutant.

Enhanced interleukin-4 production in CD4+ T cells and elevated immunoglobulin E levels in antigen-primed mice by bisphenol A and nonylphenol, endocrine disruptors: involvement of nuclear factor-AT and Ca2+

Bisphenol A (BPA) and p-nonylphenol (NP) are representative endocrine disruptors (EDs) that may have adverse effects on human health. The influence of these compounds on allergic immune responses remains unclear. In this study, we have examined the effects of BPA and NP on production of interleukin-4 (IL-4), a pro-inflammatory cytokine closely associated with allergic immune responses. Both BPA and NP significantly enhanced IL-4 production in keyhole limpet haemocyanin (KLH)-primed CD4+ T cells in a concentration-dependent manner. Treatment with BPA or NP in vivo resulted in significant increase of IL-4 production in CD4+ T cells and of antigen-specific immunoglobulin E (IgE) levels in the sera of KLH-primed mice. Furthermore, BPA and NP enhanced the activation of IL-4 gene promoter in EL4 T cells transiently transfected with IL-4 promoter/reporter constructs, and the enhancing effect mapped to a region in the IL-4 promoter containing binding sites for nuclear factor (NF)-AT. Activation of T lymphocytes by phorbol 12-myristate 13-acetate/ionomycin resulted in markedly enhanced binding activities to the NF-AT site, which significantly increased upon addition of BPA or NP, as demonstrated by the electrophoretic mobility shift assay, indicating that the transcription factor NF-AT was involved in the enhancing effect of BPA and NP on IL-4 production. The enhancement of IL-4 production by BPA or NP was significantly reduced by nitrendipine, a blocker of Ca2+ influx, and by FK506, a calcineurin inhibitor. FK506 inhibited the NF-AT-DNA binding activity and IL-4 gene promoter activity enhanced by BPA or NP. These results represent the first report describing possible enhancement of allergic response by EDs through increasing IL-4 production in CD4+ T cells and antigen-specific IgE levels in the sera via the stimulation of Ca2+/calcineurin-dependent NF-AT activation.

Formation and decomposition of hazardous chemical components contained in atmospheric aerosol particles

Air particulate matter contains a wide range of substances, some of which pose a threat to human health. Chemical reactions occurring on aerosol particles in the atmosphere can transform hazardous components and increase or decrease their potential for adverse health effects. Especially organic compounds react readily with atmospheric oxidants, and since fine aerosol particles have a high surface-to-volume ratio, their chemical composition can be efficiently changed by interaction with trace gases such as ozone and nitrogen oxides. In this paper the concepts required to understand and describe the formation and decomposition of hazardous chemical components contained in atmospheric aerosol particles are outlined. The processes at work on a molecular level in the chemical transformation of atmospheric particle components are illustrated for soot and polycyclic aromatic compounds (PACs), in particular for benzo[a]pyrene (BaP) which is one of the most prominent hazardous pollutants in the class of polycyclic aromatic hydrocarbons (PAHs). Recent results on the reaction kinetics and mechanisms of BaP degradation by ozone and nitrogen dioxide are presented. These results indicate faster degradation by atmospheric oxidants than previously estimated, which implies a higher potential for sampling artifacts and underestimation of the actual atmospheric abundance of BaP and other PAHs. Thus human exposure close to the sources of these compounds such as busy roadways may be significantly higher than previously assumed.

Effects of fractions of traffic particulate matter on TH2-cytokines, IgE levels, and bronchial hyperresponsiveness in mice

In recent decades an increased prevalence of allergic conditions has been observed in developed countries. Although lifestyles, exposure to infection, and diet are all likely important factors, many studies have also shown a strong link between industrialization and allergy. The aim of this study was to investigate which extract fractions from traffic particulate matter (TPM, collected in a tunnel in Prague) have the greatest impact on different inflammatory and immunological parameters, such as cytokine production, levels of immunoglobulin E (IgE) antibodies, and bronchial hyperresponsiveness (BHR) in mice, when the extracts are used together with birch pollen for immunization. BP2 mice were immunized with birch pollen and different fractions of TPM (fractions 1-8). They were provoked intranasally with a mixture of pollen and TPM or pollen alone before they were challenged with methacholine. The BHR was evaluated in a whole-body plethysmograph. Th2 cytokines and fibronectin concentrations were measured, and differential cell counts were performed in the bronchioalveolar lavage (BAL) fluid. Sera were collected for determination of antibody titers. The highest titers of IgE and the highest BHR were found in the positive control mice (immunized and provoked with a mixture of pollen and TPM), followed by mice immunized with pollen and fraction 2 (which contains organic acids). Fraction 2 also induced the highest number of eosinophils and increased levels of interleukin 5 (IL-5) in the BAL fluid. The highest levels of IL-5, in BAL fluid and sera, were obtained in mice immunized with fraction 6 (moderately polar compounds), a somewhat surprising result since those mice did not produce any IgE, did not have any eosinophils in their BAL, or showed almost no BHR. Our data demonstrate that fractions 2 (organic acids) and 7 (highly polar compounds) seem to contain potential adjuvants stimulating the IL-5 production, the IgE synthesis, the eosinophil recruitment, and the bronchial hyperreactivity. Further characterization at the molecular level is now necessary to be able to identify the exact nature of those potential adjuvants. This will be of help in the future to improve the quality of the urban air aerosol.

Hydroquinone, a reactive metabolite of benzene, enhances interleukin-4 production in CD4+ T cells and increases immunoglobulin E levels in antigen-primed mice

Exposure to cigarette smoke is known to increase the risk of the development of allergic disease. The mechanism is not well understood. In this study, we determined the effect of hydroquinone (HQ), a major metabolite of benzene present in large quantities in cigarette tar, on interleukin-4 (IL-4) production by CD4+ T cells. HQ significantly enhanced IL-4 production by keyhole limpet haemocyanin (KLH)-primed CD4+ T cells in a dose-dependent manner. The enhancing effect of HQ on IL-4 production was maximal at a concentration of 50 micro m. It increased the level of IL-4 production approximately 10-fold. HQ enhanced IL-4 mRNA expression and also IL-4 gene promoter activity, suggesting that the enhancing effect of HQ on IL-4 production may occur at the transcriptional level. Furthermore, the injection of KLH-primed mice with HQ resulted in a significant increase in the levels of IL-4 and immunoglobulin E. These findings provide evidence that HQ, a major component of cigarette tar, may enhance allergic immune responses by inducing the production of IL-4 in CD4+ T cells.

Calorimetric approach of the interaction and absorption of polycyclic aromatic hydrocarbons with model membranes

The ability of polycyclic aromatic hydrocarbons (PAHs) to interact with cell membranes outer lipid layer and subsequently to penetrate inside cells can be a prerequisite for exhibiting a mutagenic and carcinogenic activity. The effect exerted by pyrene, benzo[a]pyrene, and anthracene, three structurally similar polycyclic aromatic hydrocarbons possessing mutagenic and carcinogenic activity on the thermotropic behavior of model membranes represented by dimyristoylphosphatidylcholine (DMPC) vesicles, was investigated by differential scanning calorimetry (DSC). The examined compounds, when dispersed in liposomes during their preparation, exerted a different action on the gel-to-liquid crystal phase transition of DMPC multilamellar vesicles. Pyrene and benzo[a]pyrene affected the transition temperature (Tm), shifting it toward lower values with a concomitant decrease of the associated enthalpy changes (AM). Anthracene does not significantly affect the thermotropic behavior of lipid vesicles for all tested concentrations. The interaction between PAHs and model membranes was also studied by considering the ability of such compounds as a finely powdered solid or adsorbed on soil surrogate (constituted by silica gel) to migrate through an aqueous medium. This transfer process was compared with the PAHs intermembrane transfer from PAH loaded liposomes to empty membranes. These processes can mimic absorption kinetics mediated by hydrophilic or lipophilic media. No interaction occurred between model membranes and solid PAHs. A very small effect was also observed for PAHs released by silica gel, suggesting that the migration and absorption are hindered by the aqueous layer and that their low hydrophilic character inhibits migration through the aqueous layer surrounding the multilamellar vesicles (MLV). Different behavior was observed by considering the time-dependent studies carried out by contacting, for increasing times, equivalent amounts of empty DMPC vesicles with PAH loaded ones; all compounds were able to migrate between the two different kinds of model membranes. Thus, PAHs are unable to reach and penetrate biological membranes migrating through an aqueous layer but, when dispersed in a lipophilic medium, are able to penetrate and diffuse inside a membrane. The obtained experimental results seem to validate the employment of the DSC technique in order to study the ability of bioactive compounds, not only to interact with biological membranes, but also to be adsorbed inside a cell when dispersed in a lipophilic medium.