Ozone, oxidant defense genes, and risk of asthma during adolescence

Effect of preconception SOD2 gene variants and air pollution on gestational length: evidence from a mother-baby cohort

To explore the relationship between air pollution, preconception SOD2 gene variations, and gestational length. A study was conducted on 1,846 mother-baby pairs in Henan Province. Air pollutant was gathered from environmental monitoring stations. Peripheral blood was collected from pregnant women before pregnancy and genotyped to minimize the interference of prenatal air pollution on SOD2 gene variations. Multivariable linear regression models were used to analyze the relationship between air pollution and gestational length, with an interaction term (SNP × air pollutant) included to explore the gene-environment interactions. After adjusting for covariates, it was found that exposure to carbon monoxide (CO), sulfur dioxide (SO2), ozone (O3), fine particulate matter (PM2.5), and inhalable particulate matter (PM10) was associated with decreased gestational length, while nitrogen dioxide (NO2) exposure was associated with increased gestational length (p < 0.05). Furthermore, mothers carrying the A allele of SOD2 rs4880 had an increment of 0.17 weeks in gestational length compared to those carrying the G allele (p < 0.05). Interactions on gestational length between SOD2 gene polymorphisms (rs4880, rs5746136, and rs2758352) and exposure to CO, NO2, SO2, PM2.5, and PM10 were observed. These findings suggest that SOD2 gene variations may influence the association between prenatal air pollution and gestational length.

A model of the spatiotemporal distribution of ozone-squalene reaction and ozonolysis by-products from human body

Emissions of ozone and its by-products from ozonolysis on human surfaces lead to indoor air pollution. However, the spatiotemporal distribution of such emissions in indoor environments remains unclear, which may introduce bias when assessing human exposure to ozone and ozonolysis byproducts. This study developed a computational fluid dynamics model to describe the physical and chemical processes involved in the emission of ozone-dependent volatile organic compounds from the human body. The results showed that the reaction probability of ozone in the human body depends on the ozone concentration in the bulk air. For ozone concentrations ranging from 28 ppb to 200 ppb, the reaction probabilities ranged from 5.9 × 10-5 to 1.5 × 10-4. The concentrations of ozone and ozonolysis byproducts obtained from the experimental measurements were used for model validation. The ozonolysis by-products were found to be uniformly distributed in the chamber, whereas the ozone distribution showed less uniformity. The ozone concentration near the human surface was approximately 30 %∼50 % of that in the ambient air. Overall, a model was developed to understand the effect of ozone-surface interactions on indoor air quality. This model can be applied to analyze human exposure to ozone and ozonolysis byproducts and for health risk assessment in built environments.

Heterogeneous Oxidation Products of Fine Particulate Isoprene Epoxydiol-Derived Methyltetrol Sulfates Increase Oxidative Stress and Inflammatory Gene Responses in Human Lung Cells

Hydroxyl radical (·OH)-initiated oxidation of isoprene, the most abundant nonmethane hydrocarbon in the atmosphere, is responsible for substantial amounts of secondary organic aerosol (SOA) within ambient fine particles. Fine particulate 2-methyltetrol sulfate diastereoisomers (2-MTSs) are abundant SOA products formed via acid-catalyzed multiphase chemistry of isoprene-derived epoxydiols with inorganic sulfate aerosols under low-nitric oxide conditions. We recently demonstrated that heterogeneous ·OH oxidation of particulate 2-MTSs leads to the particle-phase formation of multifunctional organosulfates (OSs). However, it remains uncertain if atmospheric chemical aging of particulate 2-MTSs induces toxic effects within human lung cells. We show that inhibitory concentration-50 (IC50) values decreased from exposure to fine particulate 2-MTSs that were heterogeneously aged for 0 to 22 days by ·OH, indicating increased particulate toxicity in BEAS-2B lung cells. Lung cells further exhibited concentration-dependent modulation of oxidative stress- and inflammatory-related gene expression. Principal component analysis was carried out on the chemical mixtures and revealed positive correlations between exposure to aged multifunctional OSs and altered expression of targeted genes. Exposure to particulate 2-MTSs alone was associated with an altered expression of antireactive oxygen species (ROS)-related genes (NQO-1, SOD-2, and CAT) indicative of a response to ROS in the cells. Increased aging of particulate 2-MTSs by ·OH exposure was associated with an increased expression of glutathione pathway-related genes (GCLM and GCLC) and an anti-inflammatory gene (IL-10).

Variability of DNA Repair and Oxidative Stress Genes Associated with Worst Pain in Breast Cancer Survivors on Aromatase Inhibitors

Pain is a problem affecting women with breast cancer (HR+BrCa) receiving aromatase inhibitor (AI) therapy. We investigated the relationship between single-nucleotide polymorphisms (SNPs) in DNA repair and oxidative stress genes and perceived worst pain after 6 months of AI therapy. We explored 39 SNPs in genes involved in DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) and oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) in women with HR+BrCa receiving adjuvant therapy (AI ± chemotherapy; n = 138). Pain was assessed via the Brief Pain Inventory. Hurdle regression was used to evaluate the relationship between each associated allele and (1) the probability of pain and (2) the severity of worst pain. ERCC2rs50872 and ERCC5rs11069498 were associated with the probability of pain and had a significant genetic risk score (GRS) model (p = 0.003). ERCC2rs50872, ERCC5rs11069498, ERCC5rs4771436, ERCC5rs4150360, PARP1rs3219058, and SEPP1rs230819 were associated with the severity of worst pain, with a significant GRS model (conditional mean estimate = 0.45; 95% CI = 0.29, 0.60; p < 0.001). These results suggest DNA repair and oxidative stress pathways may play a role in the probability of pain and the severity of worst pain. As healthcare delivery moves towards the model of precision healthcare, nurses may, in the future, be able to use these results to tailor patient care based on GRS.

Integration of transcriptomics and metabolomics to reveal the effect of ginsenoside Rg3 on allergic rhinitis in mice

Increasing studies have demonstrated that ginsenoside Rg3 (Rg3) plays an important role in the prevention and treatment of various diseases, including allergic lower airway inflammation such as asthma. To investigate the role of Rg3 in allergic upper airway disease, the effect and therapeutic mechanism of Rg3 in allergic rhinitis (AR) were studied. Ovalbumin-induced AR model mice were intragastrically administered with Rg3. Nasal symptoms, levels of IgE, IL-4, IL-5, IL-13, SOD and MDA in serum, and histopathological analysis of nasal mucosa were used to evaluate the effect of Rg3 on ameliorating AR in mice. Moreover, nasal mucosa samples from the normal control group, AR model group and high dosage of Rg3 were collected to perform omics analysis. The differentially expressed genes and significantly changed metabolites were screened based on transcriptomics and metabolomics analyses, respectively. Integrative analysis was further performed to confirm the hub genes, metabolites and pathways. After Rg3 intervention, the nasal symptoms and inflammatory infiltration were effectively improved, the levels of IgE, IL-4, IL-5, IL-13 and MDA were significantly reduced, and the level of SOD was obviously increased. The results of the qRT-PCR assay complemented the transcriptomic findings. Integrated analysis showed that Rg3 played an anti-AR role mainly by regulating the interaction network, which was constructed by 12 genes, 8 metabolites and 4 pathways. Our findings suggested that Rg3 had a therapeutic effect on ovalbumin-induced AR in mice by inhibiting inflammation development and reducing oxidative stress. The present study could provide a potential natural agent for the treatment of AR.

The J-shape Association between Total Bilirubin and Stroke in Older Patients with Obstructive Sleep Apnea Syndrome: A Multicenter Study

OBJECTIVES

To explore the relationship between total bilirubin (TBil) and stroke risk in older patients with obstructive sleep apnea syndrome (OSAS).

METHODS

A total of 1,007 patients with OSAS without stroke history aged ≥ 60 years and with complete serum TBil records were enrolled in this study. The median follow-up was 42 months. Participants were divided into four groups based on the quartile of the baseline serum TBil concentration. Multivariate Cox proportional hazards analysis and restricted cubic spline (RCS) were used to investigate the association of TBil with the incidence of new-onset stroke.

RESULTS

The PRIMARY part: the third quantile TBil level group had the lowest prevalence of stroke among the four groups. The RCS functions depicted a J-type curve relationship between TBil (3.3-33.3 µmol/L) and stroke (nonlinear P < 0.05). When the TBil level was in the range of 3.3 to 11.5 µmol/L, the possible protective influence of bilirubin against stroke in patients with OSAS enhanced with an increasing TBil level. However, when the TBil level exceeded 11.5 µmol/L and gradually increased, the effect of TBil on stroke risk became more and more pronounced. The SECONDARY part: for every 1 µmol/L increase in TBil levels in the range of 11.5 to 33.3 µmol/L, the risk of stroke in patients with OSAS increased by 16.2% (P < 0.001). In addition, there was a higher risk in women with OSAS (hazard ratio (HR)=1.292, 95% confidence interval (95%CI): 1.093-1.528; P = 0.003). Moreover, an increased TBil level alone was significantly associated with stroke in subjects aged < 75 years (HR: 1.190, 95%CI: 1.069-1.324), patients with mild-to-moderate OSAS (HR: 1.215, 95%CI: 1.083-1.364), and individuals without atrial fibrillation (AF) (HR: 1.179, 95%CI: 1.083-1.285) within a TBil level in the range of 11.5 to 33.3 µmol/L.

CONCLUSIONS

Both lower and higher bilirubin levels may increase the risk of stroke in older persons with OSAS, and there was a J-type dose-response relationship. The risk of stroke was lowest when the TBil level was approximately 11.5 µmol/L.

The role of gene-ambient air pollution interactions in paediatric asthma

Globally, asthma prevention and treatment remain a challenge. Ambient air pollution (AAP) is an environmental risk factor of special interest in asthma research. AAP is poorly defined and has been subdivided either by the origin of the air pollution or by the specific bioactive compounds. The link between AAP exposure and asthma exacerbations is well established and has been extensively reviewed. In this narrative review, we discuss the specific genetic variants that have been associated with increased AAP sensitivity and impact in paediatric asthma. We highlight the relative importance of variants associated with genes with a role in oxidant defences and the nuclear factor-κB pathway supporting a potential central role for these pathways in AAP sensitivity.

Identification of Molecular Markers Related to Immune Infiltration in Patients with Severe Asthma: A Comprehensive Bioinformatics Analysis Based on the Human Bronchial Epithelial Transcriptome

Background. Severe asthma (SA), a heterogeneous inflammatory disease characterized by immune cell infiltration, is particularly difficult to treat and manage. The airway epithelium is an important tissue in regulating innate and adaptive immunity, and targeting airway epithelial cell may contribute to improving the efficacy of asthma therapy. Methods. Bioinformatics methods were utilized to identify the hub genes and signaling pathways involved in SA. Experiments were performed to determine whether these hub genes and signaling pathways were affected by the differences in immune cell infiltration. Results. The weighted gene coexpression network analysis identified 14 coexpression modules, among which the blue and salmon modules exhibited the strongest associations with SA. The blue module was mainly enriched in actomyosin structure organization and was associated with regulating stem cell pluripotency signaling pathways. The salmon module was mainly involved in cornification, skin development, and glycosphingolipid biosynthesis-lacto and neolacto series. The protein-protein interaction network and module analysis identified 11 hub genes in the key modules. The CIBERSORTx algorithm revealed statistically significant differences in CD8+ T cells ( $P=0.013$ ), T follicular helper cells ( $P=0.002$ ), resting mast cells ( $P=0.004$ ), and neutrophils ( $P=0.002$ ) between patients with SA and mild-moderate asthma patients. Pearson’s correlation analysis identified 11 genes that were significantly associated with a variety of immune cells. We further predicted the utility of some potential drugs and validated our results in external datasets. Conclusion. Our results may help provide a better understanding of the relationship between the airway epithelial transcriptome and clinical data of SA. And this study will help to guide the development of SA-targeted molecular therapy.

Ozone Exposure and Asthma Attack in Children

Background

Increasing evidence indicated that ozone (O3) exposure could trigger asthma attacks in children. However, the effect of O3 at low concentrations is uncertain.

Purpose

This study aimed to explore the effects of O3 exposure at low concentrations on asthma attacks in children.

Methods

A total of 3,475 children with asthma attacks from the First Affiliated Hospital of Xiamen University were available for the analyses. Air pollution data and meteorological data in Xiamen during 2016-2019 were also collected. A case-crossover design and conditional logistic regression models were conducted to evaluate the association between asthma attacks and outdoor air pollution with lag structures (from lag 0 to lag 6) in both single and multi-pollutant models. Furthermore, we estimated the influence of various levels of O3 exposure on an asthma attack in three groups categorized by maximum daily 8-h sliding average ozone (O3-8 h) (O3-8 h ≥ 100 μg/m3, O3-8 h: 80-99 μg/m3, O3-8 h < 80 μg/m3).

Results

For both single-pollutant models and multi-pollutant models, when O3-8 h was higher than 80 μg/m3, O3 exposure was increased the risk of acute asthma attacks on each day of lag. The effect of O3 on children with asthma was significant when O3 concentration was higher than 100 μg/m3.

Conclusion

O3 concentration above 80 μg/m3 contributed to an increased risk of asthma attacks in children.

Nutrigenetics of antioxidant enzymes and micronutrient needs in the context of viral infections

Sustaining adequate nutritional needs of a population is a challenging task in normal times and a priority in times of crisis. There is no 'one-size-fits-all' solution that addresses nutrition. In relevance to the COVID-19 (coronavirus disease 2019) pandemic crisis, viral infections in general and RNA viruses in particular are known to induce and promote oxidative stress, consequently increasing the body's demand for micronutrients, especially those related to antioxidant enzymic systems, thus draining the body of micronutrients, and so hindering the human body's ability to cope optimally with oxidative stress. Common polymorphisms in major antioxidant enzymes, with world population minor allele frequencies ranging from 0·5 to 50 %, are related to altered enzymic function, with substantial potential effects on the body's ability to cope with viral infection-induced oxidative stress. In this review we highlight common SNP of the major antioxidant enzymes relevant to nutritional components in the context of viral infections, namely: superoxide dismutases, glutathione peroxidases and catalase. We delineate functional polymorphisms in several human antioxidant enzymes that require, especially during a viral crisis, adequate and potentially additional nutritional support to cope with the pathological consequences of disease. Thus, in face of the COVID-19 pandemic, nutrition should be tightly monitored and possibly supplemented, with special attention to those carrying common polymorphisms in antioxidant enzymes.

Antioxidant genes and susceptibility to air pollution for respiratory and cardiovascular health

Oxidative stress occurs when antioxidant defences, which are regulated by a complex network of genes, are insufficient to maintain the level of reactive oxygen species below a toxic threshold. Outdoor air pollution has long been known to adversely affect health and one prominent mechanism of action common to all pollutants is the induction of oxidative stress. An individual's susceptibility to the effects of air pollution partly depends on variation in their antioxidant genes. Thus, understanding antioxidant gene-pollution interactions has significant potential clinical and public health impacts, including the development of targeted and cost-effective preventive measures, such as setting appropriate standards which protect all members of the population. In this review, we aimed to summarize the latest epidemiological evidence on interactions between antioxidant genes and outdoor air pollution, in the context of respiratory and cardiovascular health. The evidence supporting the existence of interactions between antioxidant genes and outdoor air pollution is strongest for childhood asthma and wheeze, especially for interactions with GSTT1, GSTM1 and GSTP1, for lung function in both children and adults for several antioxidant genes (GSTT1, GSTM1, GSTP1, HMOX1, NQO1, and SOD2) and, to a more limited extent, for heart rate variability in adults for GSTM1 and HMOX1. Methodological challenges hampering a clear interpretation of these findings and understanding of true potential heterogeneity are discussed.

Multicenter Ozone Study in oldEr Subjects (MOSES): Part 2. Effects of Personal and Ambient Concentrations of Ozone and Other Pollutants on Cardiovascular and Pulmonary Function

INTRODUCTION

The Multicenter Ozone Study of oldEr Subjects (MOSES) was a multi-center study evaluating whether short-term controlled exposure of older, healthy individuals to low levels of ozone (O3) induced acute changes in cardiovascular biomarkers. In MOSES Part 1 (MOSES 1), controlled O3 exposure caused concentration-related reductions in lung function with evidence of airway inflammation and injury, but without convincing evidence of effects on cardiovascular function. However, subjects' prior exposures to indoor and outdoor air pollution in the few hours and days before each MOSES controlled O3 exposure may have independently affected the study biomarkers and/or modified biomarker responses to the MOSES controlled O3 exposures.

METHODS

MOSES 1 was conducted at three clinical centers (University of California San Francisco, University of North Carolina, and University of Rochester Medical Center) and included healthy volunteers 55 to 70 years of age. Consented participants who successfully completed the screening and training sessions were enrolled in the study. All three clinical centers adhered to common standard operating procedures and used common tracking and data forms. Each subject was scheduled to participate in a total of 11 visits: screening visit, training visit, and three sets of exposure visits consisting of the pre-exposure day, the exposure day, and the post-exposure day. After completing the pre-exposure day, subjects spent the night in a nearby hotel. On exposure days, the subjects were exposed for 3 hours in random order to 0 ppb O3 (clean air), 70 ppb O3, and 120 ppm O3. During the exposure period the subjects alternated between 15 minutes of moderate exercise and 15 minutes of rest. A suite of cardiovascular and pulmonary endpoints was measured on the day before, the day of, and up to 22 hours after each exposure.

In MOSES Part 2 (MOSES 2), we used a longitudinal panel study design, cardiopulmonary biomarker data from MOSES 1, passive cumulative personal exposure samples (PES) of O3 and nitrogen dioxide (NO2) in the 72 hours before the pre-exposure visit, and hourly ambient air pollution and weather measurements in the 96 hours before the pre-exposure visit. We used mixed-effects linear regression and evaluated whether PES O3 and NO2 and these ambient pollutant concentrations in the 96 hours before the pre-exposure visit confounded the MOSES 1 controlled O3 exposure effects on the pre- to post-exposure biomarker changes (Aim 1), whether they modified these pre- to post-exposure biomarker responses to the controlled O3 exposures (Aim 2), whether they were associated with changes in biomarkers measured at the pre-exposure visit or morning of the exposure session (Aim 3), and whether they were associated with differences in the pre- to post-exposure biomarker changes independently of the controlled O3 exposures (Aim 4).

RESULTS

Ambient pollutant concentrations at each site were low and were regularly below the National Ambient Air Quality Standard levels. In Aim 1, the controlled O3 exposure effects on the pre- to post-exposure biomarker differences were little changed when PES or ambient pollutant concentrations in the previous 96 hours were included in the model, suggesting these were not confounders of the controlled O3 exposure/biomarker difference associations. In Aim 2, effects of MOSES controlled O3 exposures on forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were modified by ambient NO2 and carbon monoxide (CO), and PES NO2, with reductions in FEV1 and FVC observed only when these concentrations were "Medium" or "High" in the 72 hours before the pre-exposure visit. There was no such effect modification of the effect of controlled O3 exposure on any other cardiopulmonary biomarker.

As hypothesized for Aim 3, increased ambient O3 concentrations were associated with decreased pre-exposure heart rate variability (HRV). For example, high frequency (HF) HRV decreased in association with increased ambient O3 concentrations in the 96 hours before the pre-exposure visit (-0.460 ln[ms2]; 95% CI, -0.743 to -0.177 for each 10.35-ppb increase in O3; P = 0.002). However, in Aim 4 these increases in ambient O3 were also associated with increases in HF and low frequency (LF) HRV from pre- to post-exposure, likely reflecting a "recovery" of HRV during the MOSES O3 exposure sessions. Similar patterns across Aims 3 and 4 were observed for LF (the other primary HRV marker), and standard deviation of normal-to-normal sinus beat intervals (SDNN) and root mean square of successive differences in normal-to-normal sinus beat intervals (RMSSD) (secondary HRV markers).

Similar Aim 3 and Aim 4 patterns were observed for FEV1 and FVC in association with increases in ambient PM with an aerodynamic diameter ≤ 2.5 μm (PM2.5), CO, and NO2 in the 96 hours before the pre-exposure visit. For Aim 3, small decreases in pre-exposure FEV1 were significantly associated with interquartile range (IQR) increases in PM2.5 concentrations in the 1 hour before the pre-exposure visit (-0.022 L; 95% CI, -0.037 to -0.006; P = 0.007), CO in the 3 hours before the pre-exposure visit (-0.046 L; 95% CI, -0.076 to -0.016; P = 0.003), and NO2 in the 72 hours before the pre-exposure visit (-0.030 L; 95% CI, -0.052 to -0.008; P = 0.007). However, FEV1 was not associated with ambient O3 or sulfur dioxide (SO2), or PES O3 or NO2 (Aim 3). For Aim 4, increased FEV1 across the exposure session (post-exposure minus pre-exposure) was marginally significantly associated with each 4.1-ppb increase in PES O3 concentration (0.010 L; 95% CI, 0.004 to 0.026; P = 0.010), as well as ambient PM2.5 and CO at all lag times. FVC showed similar associations, with patterns of decreased pre-exposure FVC associated with increased PM2.5, CO, and NO2 at most lag times, and increased FVC across the exposure session also associated with increased concentrations of the same pollutants, reflecting a similar recovery. However, increased pollutant concentrations were not associated with adverse changes in pre-exposure levels or pre- to post-exposure changes in biomarkers of cardiac repolarization, ST segment, vascular function, nitrotyrosine as a measure of oxidative stress, prothrombotic state, systemic inflammation, lung injury, or sputum polymorphonuclear leukocyte (PMN) percentage as a measure of airway inflammation.

CONCLUSIONS

Our previous MOSES 1 findings of controlled O3 exposure effects on pulmonary function, but not on any cardiovascular biomarker, were not confounded by ambient or personal O3 or other pollutant exposures in the 96 and 72 hours before the pre-exposure visit. Further, these MOSES 1 O3 effects were generally not modified, blunted, or lessened by these same ambient and personal pollutant exposures. However, the reductions in markers of pulmonary function by the MOSES 1 controlled O3 exposure were modified by ambient NO2 and CO, and PES NO2, with reductions observed only when these pollutant concentrations were elevated in the few hours and days before the pre-exposure visit. Increased ambient O3 concentrations were associated with reduced HRV, with "recovery" during exposure visits. Increased ambient PM2.5, NO2, and CO were associated with reduced pulmonary function, independent of the MOSES-controlled O3 exposures. Increased pollutant concentrations were not associated with pre-exposure or pre- to post-exposure changes in other cardiopulmonary biomarkers. Future controlled exposure studies should consider the effect of ambient pollutants on pre-exposure biomarker levels and whether ambient pollutants modify any health response to a controlled pollutant exposure.

A Polymorphism in the Catalase Gene Promoter Confers Protection against Severe RSV Bronchiolitis

Respiratory syncytial virus (RSV) infection is associated with oxidative lung injury, decreased levels of antioxidant enzymes (AOEs), and the degradation of the transcription factor NF-E2-related factor 2 (NRF2), a master regulator of AOE expression. Single nucleotide polymorphisms (SNPs) in AOE and NRF2 genes have been associated with various lung disorders. To test whether specific NRF2 and/or AOE gene SNPs in children with RSV lower respiratory tract infection were associated with disease severity, one hundred and forty one children <24 month of age with bronchiolitis were assessed for seven AOE and two NRF2 SNPs, and data were correlated with disease severity, which was determined by need of oxygen supplementation and intensive care support. One SNP in the promoter region of the catalase gene, rs1001179, which is associated with higher enzyme expression, was significantly underrepresented (p = 0.01, OR 0.38) among patients with moderate to severe RSV bronchiolitis, suggesting a protective effect against disease severity. Our results suggest that increasing catalase expression/activity could exert a protective role in the context of RSV infection and represent a potential novel therapeutic target to ameliorate viral-induced lung disease.

CC16 Levels into Adult Life Are Associated with Nitrogen Dioxide Exposure at Birth

Rationale: Lung function and growth are adversely associated with nitrogen dioxide (NO2) exposure. Lower levels of circulating club cell secretory protein (CC16) in childhood are also associated with subsequent decreased lung function. NO2 exposure may induce epithelial damage in lungs and alter club cell proliferation and morphology.Objectives: To determine if increased ambient NO2 levels at participants' home addresses in early life were associated with decreased levels of CC16 from age 6 to 32 years.Methods: Participants were enrolled at birth in the Tucson Children's Respiratory Study and had circulating CC16 measured at least once between age 6 and 32. Linear mixed models were used to determine the association between estimated ambient NO2 exposure at participants' home address at birth or age 6 with CC16 levels from age 6 to 32.Measurements and Main Results: NO2 exposures at birth or age 6 were available for 777 children with one or more CC16 measurement. We found a negative association between NO2 exposure and CC16 levels, with a 4.7% (95% confidence interval, -8.6 to -0.7) decrease in CC16 levels from age 6 to 32 per interquartile range increase in NO2 exposure (6.0 ppb) at the participants' birth address. We observed modification by race (p interaction = 0.04), with stronger associations among participants with at least one black parent (-29.6% [95% confidence interval, -42.9% to -13.2%] per interquartile range). NO2 at participant's age 6 address was not significantly associated with CC16 levels (-1.9%; 95% confidence interval, -6.3 to 2.6).Conclusions: Higher exposure to NO2 at birth is associated with persistently low levels of CC16 from 6 to 32 years.

Exposure to outdoor air pollution and its human health outcomes: A scoping review

Despite considerable air pollution prevention and control measures that have been put into practice in recent years, outdoor air pollution remains one of the most important risk factors for health outcomes. To identify the potential research gaps, we conducted a scoping review focused on health outcomes affected by outdoor air pollution across the broad research area. Of the 5759 potentially relevant studies, 799 were included in the final analysis. The included studies showed an increasing publication trend from 1992 to 2008, and most of the studies were conducted in Asia, Europe, and North America. Among the eight categorized health outcomes, asthma (category: respiratory diseases) and mortality (category: health records) were the most common ones. Adverse health outcomes involving respiratory diseases among children accounted for the largest group. Out of the total included studies, 95.2% reported at least one statistically positive result, and only 0.4% showed ambiguous results. Based on our study, we suggest that the time frame of the included studies, their disease definitions, and the measurement of personal exposure to outdoor air pollution should be taken into consideration in any future research. The main limitation of this study is its potential language bias, since only English publications were included. In conclusion, this scoping review provides researchers and policy decision makers with evidence taken from multiple disciplines to show the increasing prevalence of outdoor air pollution and its adverse effects on health outcomes.

Critical review of long-term ozone exposure and asthma development

Asthma, a chronic respiratory disorder with complex etiology and various phenotypes, is a considerable public health concern in the USA and worldwide. While there is evidence suggesting ambient ozone exposure may exacerbate asthma, information regarding the potential role of ozone in asthma development is more limited. Thus, we conducted a critical review of observational epidemiology studies to determine whether long-term ambient ozone exposure is a risk factor for asthma development. We identified 14 relevant studies; 11 evaluated asthma development in children, while three studies, based on a single cohort, assessed this outcome in adults. Studies of childhood asthma and long-term ozone exposure - including exposure in utero, during the first year of life and during early childhood - reported inconsistent findings, which were further weakened by critical methodological limitations in statistical analyses and in exposure and outcome assessments, such as exposure measurement error and a lack of adjustment for key confounders. For adult-onset asthma, long-term ozone exposure was associated with an increased risk in men but not women. In addition to considerable uncertainties due to potential exposure measurement error and a lack of adjustment for key confounders, this study has limited generalizability to the US general population. While experimental evidence indicates that it may be biologically plausible that long-term ozone exposure could contribute to asthma development, it does not provide insight regarding an established mode of action. Future research is needed to address the uncertainties regarding the role of long-term ambient ozone exposure in asthma development.

Exercise-Induced Bronchoconstriction and the Air We Breathe

An association between airway dysfunction and airborne pollutant inhalation exists. Volatilized airborne fluorocarbons in ski wax rooms, particulate matter, and trichloromines in indoor environments are suspect to high prevalence of exercise-induced bronchoconstriction and new-onset asthma in athletes competing in cross-country skiing, ice rink sports, and swimming. Ozone is implicated in acute decreases in lung function and the development of new-onset asthma from exposure during exercise. Mechanisms and genetic links are proposed for pollution-related new-onset asthma. Oxidative stress from airborne pollutant inhalation is a common thread to progression of airway damage. Key pollutants and mechanisms for each are discussed.

Association of GPx1 P198L and CAT C-262T Genetic Variations With Polycystic Ovary Syndrome in Chinese Women

Background: Oxidative stress plays an important role in the pathogenesis of polycystic ovary syndrome (PCOS). Glutathione peroxidase 1 (GPx1) and catalase (CAT) are the major intracellular antioxidant enzymes that can detoxify hydrogen peroxide into water, preventing cellular injury from reactive oxygen species. The aim of the present study was to investigate the association of GPx1 P198L (Pro198Leu, C559T, rs1050450) and CAT C-262T (rs1001179) genetic polymorphisms with the risk of PCOS and evaluate the effects of the genotypes on clinical, hormonal, metabolic and oxidative stress parameters in Chinese women. Methods: This is a case-control study of 654 patients with PCOS and 535 controls. The GPx1 P198L, CAT C-262T, and superoxide dismutase 2 (SOD2) A16V genotypes were determined by polymerase chain reaction amplification and restriction analysis. Clinical, hormonal, metabolic and oxidative stress parameters were also analyzed. Results: The frequencies of the PL + LL genotype (14.1 vs. 8.4%) and L allele (7.3 vs. 4.4%) of GPx1 P198L polymorphism were significantly higher in patients with PCOS than in control subjects. Genotype (PL + LL) remained a significant predictor for PCOS in prognostic models including age, body mass index (BMI), insulin resistance index, total cholesterol, triglycerides, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol as covariates (OR = 2.105, 95%CI: 1.330-3.331, P = 0.001). Patients carrying the L allele had relatively high average ovarian volume, waist circumference, and malondialdehyde levels (P < 0.07) compared with patients with the PP genotype. We also demonstrated that the subjects with both GPx1 L and SOD2 A alleles further increase the risk of PCOS compared with the individuals carrying the PP/VV genotype after adjusting for age and BMI (OR = 5.774, 95%CI: 2.243-14.863, P < 0.001). However, no significant differences were observed in the frequencies of the CAT C-262T genotypes and alleles between PCOS and control groups. Conclusions: The GPx1 P198L, but not CAT C-262T, genetic polymorphism is associated with the risk of PCOS in Chinese women.

Interaction Between Catalase Gene Promoter Polymorphisms and Indoor Environmental Exposure in Childhood Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a highly prevalent chronic inflammatory disease affecting nearly 40% of the children in Taiwan. Genetic susceptibility may interact with specific environmental factors leading to allergic disease development.

METHODS

To assess the interactions between catalase gene promoter polymorphisms and environmental factors on the risk of AR, we conducted a case-control study in Taiwan. Data on AR and environmental factors were collected from 800 children using the ISSAC questionnaire. The case group consisted of 263 children with AR, and the control group consisted of =537 healthy children. Genotyping was performed for rs1001179 and rs769214 polymorphisms, and environmental exposure was assessed using four indicators including dwelling visible molds, mold odor, moisture on surfaces, and water damage.

RESULTS

We found that the presence of visible molds, mold odor, and moisture was associated with AR. An apparent joint effect of the GG genotype and mold odor, compared with the AA and AG combined genotypes and without any exposure indicator (adjusted odds ratio [OR] = 1.95 [95% confidence interval (CI) = 1.20, 3.18]; interaction adjusted odds ratio = 2.59 [95% CI = 1.27, 5.30]), was observed.

CONCLUSIONS

Our findings suggest that gene-environment interactions between the catalase polymorphism rs769214 and mold odor may play an important role in childhood AR development.

Catalase C-262T Gene Variant in Patients with Bronchial Asthma

Bronchial asthma (BA) is a chronic inflammatory disease of the airways in the pathogenesis of which oxidative stress has a very important role. Single nucleotide polymorphisms (SNPs) in catalase gene may result in decreased antioxidative defense capacity, and thus a higher risk for BA development. Since oxidative stress has an important role in the pathogenesis of BA and catalase has a key role in antioxidant defense, the aim of this study was to examine the association of CAT C-262T polymorphism with BA in Serbian patients with BA.

A total of 170 subjects (79 patients with BA and 91 controls) were screened for CAT C-262T SNP using PCR-RFLP method.

The analysis of genotype distribution did not show statistically significant differences between BA patients and controls (p > 0.05). Moreover, no differences were detected when comparison was performed based on dominant or recessive model. The distribution of CAT-262C and CAT-262T alleles did not show differences between patients and healthy controls (p = 0.715; OR = 1.091; 95% CI = 0.684–1.741). Further analysis of genotype and allele distributions, based on stratification by sex, did not show significant differences between BA patients and controls (p > 0.05).

This is the first study that examined CAT C-262T (rs1001179) SNP in Serbian patients with BA. The results obtained in this study showed that biallelic SNP at the position-262 in the catalase gene is not associated with BA in the Serbian population.

Susceptibility Factors Relevant for the Association Between Long-Term Air Pollution Exposure and Incident Asthma

In this review, we identified 15 studies in children and 10 studies in adults that assessed the association between long-term exposure to air pollution and incident asthma and that conducted stratified analyses to explore potential susceptibility factors. Overall, adult never-/former smokers seem to be at higher risk of incident asthma due to air pollution. Children without atopy and children from low socioeconomic status families also seem to be at higher risk of incident asthma due to air pollution. While interaction between air pollution and genes involved in the response to oxidative stress pathways have been explored, results are somewhat inconsistent and in need of replication. To evaluate interactions, large sample sizes are necessary, and much more research, including data pooling from existing studies, is needed to further explore susceptibility factors for asthma incidence due to long-term air pollution exposure.

"Cumulative Stress": The Effects of Maternal and Neonatal Oxidative Stress and Oxidative Stress-Inducible Genes on Programming of Atopy

Although extensive epidemiological and laboratory studies have been performed to identify the environmental and immunological causes of atopy, genetic predisposition seems to be the biggest risk factor for allergic diseases. The onset of atopic diseases may be the result of heritable changes of gene expression, without any alteration in DNA sequences occurring in response to early environmental stimuli. Findings suggest that the establishment of a peculiar epigenetic pattern may also be generated by oxidative stress (OS) and perpetuated by the activation of OS-related genes. Analyzing the role of maternal and neonatal oxidative stress and oxidative stress-inducible genes, the purpose of this review was to summarize what is known about the relationship between maternal and neonatal OS-related genes and the development of atopic diseases.

A Time-Stratified Case-Crossover Study of Ambient Ozone Exposure and Emergency Department Visits for Specific Respiratory Diagnoses in California (2005-2008)

BACKGROUND

Studies have explored ozone's connection to asthma and total respiratory emergency department visits (EDVs) but have neglected other specific respiratory diagnoses despite hypotheses relating ozone to respiratory infections and allergic responses.

OBJECTIVE

We examined relationships between ozone and EDVs for respiratory visits, including specifically acute respiratory infections (ARI), asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and upper respiratory tract inflammation (URTI).

METHODS

We conducted a multi-site time-stratified case-crossover study of ozone exposures for approximately 3.7 million respiratory EDVs from 2005 through 2008 among California residents living within 20 km of an ozone monitor. Conditional logistic regression was used to estimate associations by climate zone. Random effects meta-analysis was then applied to estimate pooled excess risks (ER). Effect modification by season, distance from the monitor and individual demographic characteristics (i.e., age, race/ethnicity, sex, and payment method), and confounding by other gaseous air pollutants were also investigated. Meta-regression was utilized to explore how climate zone-level meteorological, demographic, and regional differences influenced estimates.

RESULTS

We observed ozone-associated increases in all respiratory, asthma, and ARI visits, which were slightly larger in the warm season [asthma ER per 10-ppb increase in mean of same and previous 3 days ozone exposure (lag03) = 2.7%, 95% CI: 1.5, 3.9; ARI ERlag03 = 1.4%, 95% CI: 0.8, 1.9]. EDVs for pneumonia, COPD, and URTI were also significantly associated with ozone exposure over the whole year, but typically more consistently so during the warm season.

CONCLUSIONS

Short-term ozone exposures among California residents living near an ozone monitor were positively associated with EDVs for asthma, ARI, pneumonia, COPD, and URTI from 2005 through 2008. Those associations were typically larger and more consistent during the warm season. Our findings suggest that these outcomes should be considered when evaluating the potential health benefits of reducing ozone concentrations.

CITATION

Malig BJ, Pearson DL, Chang YB, Broadwin R, Basu R, Green RS, Ostro B. 2016. A time-stratified case-crossover study of ambient ozone exposure and emergency department visits for specific respiratory diagnoses in California (2005-2008). Environ Health Perspect 124:745-753; http://dx.doi.org/10.1289/ehp.1409495.

Polymorphisms in DNA repair and oxidative stress genes associated with pre-treatment cognitive function in breast cancer survivors: an exploratory study

PURPOSE

The purpose of this exploratory candidate gene association study was to examine relationships between polymorphisms in oxidative stress and DNA repair genes and pre-adjuvant therapy cognitive function (CF) in postmenopausal women diagnosed with early stage-breast cancer.

METHODS

Using a neuropsychological test battery, CF was assessed in 138 women diagnosed with breast cancer prior to initiation of adjuvant therapy and 81 age- and education-matched controls and summarized across eight composites. Participants were genotyped for 39 functional or tagging single nucleotide polymorphisms (SNPs) of select oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) and DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) genes. Multiple linear regression was used to determine if the presence or absence of one or more minor alleles account for variability in CF composite scores. Based on regression findings from the analysis of individual SNPs, weighted multi-gene, multi-polymorphism genetic risk scores (GRSs) were calculated to evaluate the collective effect of possession of multiple protective and/or risk alleles.

RESULTS

Each CF composite was significantly (p < 0.05) associated with one or more oxidative stress and DNA repair gene polymorphisms evaluated either by SNP main effects and/or SNP-by-prescribed breast cancer treatment group interactions. Each computed GRS was found to be significantly (p < 0.001) related to its corresponding CF composite. All associations were positive suggesting that as overall genetic protection increases, CF composite score increases (indicating better performance).

CONCLUSIONS

These findings suggest that genetic variation in the oxidative stress and DNA repair pathways may play an important role in pre-adjuvant therapy CF in breast cancer survivors.

Do Variants in GSTs Modify the Association between Traffic Air Pollution and Asthma in Adolescence?

Polymorphisms in genes involved in the oxidative stress response may partially explain the documented heterogeneous associations between traffic-related air pollution (TRAP) exposure and asthma and allergies in children. We investigated whether the GSTT1, GSTM1 and GSTP1 gene polymorphisms modified the associations between TRAP exposure during the first year of life and asthma, wheeze and hay fever in adolescence. We used a birth cohort of 620 high risk infants from the Melbourne Atopy Cohort Study. TRAP exposure during the first year of life was defined as the cumulative length of major roads within 150 m of each participant’s residence during the first year of life. Wheeze, asthma and hay fever were measured at ages 12 (n = 370) and 18 (n = 434) years. The associations and interactions with glutathione S-transferases (GST s) were investigated using regression models. Overall, there was no relationship between TRAP exposure during the first year of life and current asthma, wheeze and hay fever at ages 12 or 18 years. However, in GSTT1 null carriers, every 100 m increase in cumulative lengths of major road exposure during the first year of life was associated with a 2.31-fold increased risk of wheeze and a 2.15-fold increased risk of asthma at 12 years. TRAP is associated with some respiratory outcomes in carriers of genetic polymorphisms in oxidative stress metabolism genes.

[Genetic and biochemical mechanisms of involvement of antioxidant defense enzymes in the development of bronchial asthma]

In the present review we have analyzed and summarized recent literature data on genetic and biochemical mechanisms responsible for involvement of antioxidant defense enzymes in the etiology and pathogenesis of bronchial asthma. It has been shown that the mechanisms of asthma development are linked with genetically determined abnormalities in the functioning of antioxidant defense enzymes. These alterations are accompanied by a systemic imbalance between oxidative and anti-oxidative reactions with the shift of the redox state toward increased free radical production and oxidative stress, a key element in the pathogenesis of bronchial asthma.

Gene-environment interaction from international cohorts: impact on development and evolution of occupational and environmental lung and airway disease

Environmental and occupational pulmonary diseases impose a substantial burden of morbidity and mortality on the global population. However, it has been long observed that only some of those who are exposed to pulmonary toxicants go on to develop disease; increasingly, it is being recognized that genetic differences may underlie some of this person-to-person variability. Studies performed throughout the globe are demonstrating important gene-environment interactions for diseases as diverse as chronic beryllium disease, coal workers' pneumoconiosis, silicosis, asbestosis, byssinosis, occupational asthma, and pollution-associated asthma. These findings have, in many instances, elucidated the pathogenesis of these highly complex diseases. At the same time, however, translation of this research into clinical practice has, for good reasons, proceeded slowly. No genetic test has yet emerged with sufficiently robust operating characteristics to be clearly useful or practicable in an occupational or environmental setting. In addition, occupational genetic testing raises serious ethical and policy concerns. Therefore, the primary objective must remain ensuring that the workplace and the environment are safe for all.

Association of HMOX1 and NQO1 Polymorphisms with Metabolic Syndrome Components

Metabolic syndrome (MetS) is among the most important public health problems worldwide, and is recognized as a major risk factor for various illnesses, including type 2 diabetes mellitus, obesity, and cardiovascular diseases. Recently, oxidative stress has been suggested as part of MetS aetiology. The heme oxygenase 1 (HMOX1) and NADH:quinone oxidoreductase 1 (NQO1) genes are crucial mediators of cellular defence against oxidative stress. In the present study, we analysed the associations of HMOX1 (GT)n and NQO1 C609T polymorphisms with MetS and its components. Our study population comprised 735 Mexican Mestizos unrelated volunteers recruited from different tertiary health institutions from Mexico City. In order to know the HMOX1 (GT)n and NQO1 C609T allele frequencies in Amerindians, we included a population of 241 Amerindian native speakers. Their clinical and demographic data were recorded. The HMOX1 (GT)n polymorphism was genotyped using PCR and fluorescence technology. NQO1 C609T polymorphism genotyping was performed using TaqMan probes. Short allele (<25 GT repeats) of the HMOX1 polymorphism was associated with high systolic and diastolic blood pressure, and the T allele of the NQO1 C609T polymorphism was associated with increased triglyceride levels and decreased HDL-c levels, but only in individuals with MetS. This is the first study to analyse the association between MetS and genes involved in oxidative stress among Mexican Mestizos. Our data suggest that polymorphisms of HMOX1 and NQO1 genes are associated with a high risk of metabolic disorders, including high systolic and diastolic blood pressure, hypertriglyceridemia, and low HDL-c levels in Mexican Mestizo individuals.

Chronic effects of air pollution on respiratory health in Southern California children: findings from the Southern California Children's Health Study

Outdoor air pollution is one of the leading contributors to adverse respiratory health outcomes in urban areas around the world. Children are highly sensitive to the adverse effects of air pollution due to their rapidly growing lungs, incomplete immune and metabolic functions, patterns of ventilation and high levels of outdoor activity. The Children's Health Study (CHS) is a continuing series of longitudinal studies that first began in 1993 and has focused on demonstrating the chronic impacts of air pollution on respiratory illnesses from early childhood through adolescence. A large body of evidence from the CHS has documented that exposures to both regional ambient air and traffic-related pollutants are associated with increased asthma prevalence, new-onset asthma, risk of bronchitis and wheezing, deficits of lung function growth, and airway inflammation. These associations may be modulated by key genes involved in oxidative-nitrosative stress pathways via gene-environment interactions. Despite successful efforts to reduce pollution over the past 40 years, air pollution at the current levels still brings many challenges to public health. To further ameliorate adverse health effects attributable to air pollution, many more toxic pollutants may require regulation and control of motor vehicle emissions and other combustion sources may need to be strengthened. Individual interventions based on personal susceptibility may be needed to protect children's health while control measures are being implemented.

The role of genetic polymorphisms in antioxidant enzymes and potential antioxidant therapies in neonatal lung disease

SIGNIFICANCE

Oxidative stress is involved in the development of newborn lung diseases, such as bronchopulmonary dysplasia and persistent pulmonary hypertension of the newborn. The activity of antioxidant enzymes (AOEs), which is impaired as a result of prematurity and oxidative injury, may be further affected by specific genetic polymorphisms or an unfavorable combination of more of them.

RECENT ADVANCES

Genetic polymorphisms of superoxide dismutase and catalase were recently demonstrated to be protective or risk factors for the main complications of prematurity. A lot of research focused on the potential of different antioxidant strategies in the prevention and treatment of lung diseases of the newborn, providing promising results in experimental models.

CRITICAL ISSUES

The effect of different genetic polymorphisms on protein synthesis and activity has been poorly detailed in the newborn, hindering to derive conclusive results from the observed associations with adverse outcomes. Therapeutic strategies that aimed at enhancing the activity of AOEs were poorly studied in clinical settings and partially failed to produce clinical benefits.

FUTURE DIRECTIONS

The clarification of the effects of genetic polymorphisms on the proteomics of the newborn is mandatory, as well as the assessment of a larger number of polymorphisms with a possible correlation with adverse outcome. Moreover, antioxidant treatments should be carefully translated to clinical settings, after further details on optimal doses, administration techniques, and adverse effects are provided. Finally, the study of genetic polymorphisms could help select a specific high-risk population, who may particularly benefit from targeted antioxidant strategies.

Dynamic transcriptional and epigenomic reprogramming from pediatric nasal epithelial cells to induced pluripotent stem cells

BACKGROUND

Induced pluripotent stem cells (iPSCs) hold tremendous potential, both as a biological tool to uncover the pathophysiology of disease by creating relevant human cell models and as a source of cells for cell-based therapeutic applications. Studying the reprogramming process will also provide significant insight into tissue development.

OBJECTIVE

We sought to characterize the derivation of iPSC lines from nasal epithelial cells (NECs) isolated from nasal mucosa samples of children, a highly relevant and easily accessible tissue for pediatric populations.

METHODS

We performed detailed comparative analysis on the transcriptomes and methylomes of NECs, iPSCs derived from NECs (NEC-iPSCs), and embryonic stem cells (ESCs).

RESULTS

NEC-iPSCs express pluripotent cell markers, can differentiate into all 3 germ layers in vivo and in vitro, and have a transcriptome and methylome remarkably similar to those of ESCs. However, residual DNA methylation marks exist, which are differentially methylated between NEC-iPSCs and ESCs. A subset of these methylation markers related to epithelium development and asthma and specific to NEC-iPSCs persisted after several passages in vitro, suggesting the retention of an epigenetic memory of their tissue of origin. Our analysis also identified novel candidate genes with dynamic gene expression and DNA methylation changes during reprogramming, which are indicative of possible roles in airway epithelium development.

CONCLUSION

NECs are an excellent tissue source to generate iPSCs in pediatric asthmatic patients, and detailed characterization of the resulting iPSC lines would help us better understand the reprogramming process and retention of epigenetic memory.

Association of short-term increases in ambient air pollution and timing of initial asthma diagnosis among Medicaid-enrolled children in a metropolitan area

OBJECTIVE

We investigated associations of short-term changes in ambient ozone (O3), fine particulate matter (PM2.5) and nitrogen dioxide (NO2) concentrations and the timing of new-onset asthma, using a large, high-risk population in an area with historically high ozone levels.

METHODS

The study population included 18,289 incident asthma cases identified among Medicaid-enrolled children in Harris County Texas between 2005-2007, using Medicaid Analytic Extract enrollment and claims files. We used a time-stratified case-crossover design and conditional logistic regression to assess the effect of increased short-term pollutant concentrations on the timing of asthma onset.

RESULTS

Each 10 ppb increase in ozone was significantly associated with new-onset asthma during the warm season (May-October), with the strongest association seen when a 6-day cumulative average period was used as the exposure metric (odds ratio [OR]=1.05, 95% confidence interval [CI], 1.02-1.08). Similar results were seen for NO2 and PM2.5 (OR=1.07, 95% CI, 1.03-1.11 and OR=1.12, 95% CI, 1.03-1.22, respectively), and PM2.5 also had significant effects in the cold season (November-April), 5-day cumulative lag (OR=1.11. 95% CI, 1.00-1.22). Significantly increased ORs for O3 and NO2 during the warm season persisted in co-pollutant models including PM2.5. Race and age at diagnosis modified associations between ozone and onset of asthma.

CONCLUSION

Our results indicate that among children in this low-income urban population who developed asthma, their initial date of diagnosis was more likely to occur following periods of higher short-term ambient pollutant levels.

Effects of antioxidant supplements and nutrients on patients with asthma and allergies

Asthma and allergic diseases have become a worldwide public health concern because of their increased prevalence. Despite decades of research on risk factors, the causes of these disorders are poorly understood. They are thought to develop through complex interactions between genetic and environmental factors. Because pulmonary and systemic oxidative stress increase inflammatory responses relevant to asthma and allergy, dietary or vitamin supplementation with antioxidants (a broad and varied category) has been proposed as an approach to reducing asthma incidence or morbidity. Meta-analyses of observational epidemiologic studies of variable methodological quality suggest associations of relatively low dietary intake of antioxidants and higher asthma and allergy prevalence. However, there have been few longitudinal studies of maternal or child dietary or vitamin/supplement antioxidant intake and asthma/allergy development. Moreover, there are no clinical trial data to support the use of dietary antioxidants or supplements to prevent asthma or allergy. A few small clinical trials suggest that specific antioxidants from diet or vitamin supplements might improve asthma control or lung function in asthmatic children or adults. Studies suggest that responses to antioxidants might be modified by life stage, genetic susceptibility, and environmental sources of oxidative stress. Large trials of antioxidant vitamin supplementation to prevent cancer suggest an increase in overall mortality with antioxidant vitamin supplementation, at least in populations with sufficient dietary antioxidant intake. This cautionary experience suggests that future trials to assess whether antioxidants reduce asthma incidence or improve asthma control should focus on supplementation of dietary sources of antioxidants. The potential benefits and risks of trials of vitamin supplements might be considered in special situations in which vulnerable populations have marked deficiency in dietary antioxidants, poor access to dietary antioxidants, and high exposure to environmental sources of oxidants.

Human catalase, its polymorphisms, regulation and changes of its activity in different diseases

Catalase (CAT) is a well-studied enzyme that plays an important role in protecting cells against the toxic effects of hydrogen peroxide. In human, it has been implicated in different physiological and pathological conditions. This review summarizes the information available on the function and role of CAT polymorphisms in pathogenesis of various pathophysiological states as well as on the regulation of CAT gene expression. Numerous studies have described the CAT polymorphisms and their link with various diseases. Changes in the CAT levels were reported in many different diseases and polymorphisms in the CAT gene were shown to be associated with different pathophysiological states, e.g. hypertension, diabetes mellitus, insulin resistance, dyslipidaemia, asthma, bone metabolism or vitiligo. Regulation of the CAT gene expression plays an important role in the levels of CAT. The catalase gene expression is regulated by various mechanisms involving e.g. peroxisome proliferator-activated receptor γ (PPARγ), tumour necrosis factor α (TNF-α), p53 protein and hypermethylation of CpG islands in the catalase promoter. Transcription of the CAT gene is mainly influenced by the -262 C/T and -844 A/G polymorphisms. A common polymorphism -262 C/T in the promoter region has been found to be associated with altered CAT activities. Apart from genetic factors, the activities of CAT may be affected by age, seasonal variations, physical activity, or a number of chemical compounds. Future investigations are necessary to elucidate the role of CAT in pathogenesis of oxidative stress-related diseases.

ESTIMATING DAILY NITROGEN DIOXIDE LEVEL: EXPLORING TRAFFIC EFFECTS

Data used to assess acute health effects from air pollution typically have good temporal but poor spatial resolution or the opposite. A modified longitudinal model was developed that sought to improve resolution in both domains by bringing together data from three sources to estimate daily levels of nitrogen dioxide (NO₂) at a geographic location. Monthly NO₂ measurements at 316 sites were made available by the Study of Traffic, Air quality and Respiratory health (STAR). Four US Environmental Protection Agency monitoring stations have hourly measurements of NO₂. Finally, the Connecticut Department of Transportation provides data on traffic density on major roadways, a primary contributor to NO₂ pollution. Inclusion of a traffic variable improved performance of the model, and it provides a method for estimating exposure at points that do not have direct measurements of the outcome. This approach can be used to estimate daily variation in levels of NO₂ over a region.

Allergic diseases and air pollution

The prevalence of allergic diseases has been increasing rapidly, especially in developing countries. Various adverse health outcomes such as allergic disease can be attributed to rapidly increasing air pollution levels. Rapid urbanization and increased energy consumption worldwide have exposed the human body to not only increased quantities of ambient air pollution, but also a greater variety of pollutants. Many studies clearly demonstrate that air pollutants potently trigger asthma exacerbation. Evidence that transportation-related pollutants contribute to the development of allergies is also emerging. Moreover, exposure to particulate matter, ozone, and nitrogen dioxide contributes to the increased susceptibility to respiratory infections. This article focuses on the current understanding of the detrimental effects of air pollutants on allergic disease including exacerbation to the development of asthma, allergic rhinitis, and eczema as well as epigenetic regulation.

Selection of genes for gene-environment interaction studies: a candidate pathway-based strategy using asthma as an example

BACKGROUND

The identification of gene by environment (GxE) interactions has emerged as a challenging but essential task to fully understand the complex mechanism underlying multifactorial diseases. Until now, GxE interactions have been investigated by candidate approaches examining a small number of genes, or agnostically at the genome wide level.

PRESENTATION OF THE HYPOTHESIS

In this paper, we propose a gene selection strategy for investigation of gene-environment interactions. This strategy integrates the information on biological processes shared by genes, the canonical pathways to which they belong and the biological knowledge related to the environment in the gene selection process. It relies on both bioinformatics resources and biological expertise.

TESTING THE HYPOTHESIS

We illustrate our strategy by considering asthma, tobacco smoke as the environmental exposure, and genes sharing the same biological function of "response to oxidative stress". Our filtering strategy leads to a list of 28 pathways involving 182 genes for further GxE investigation.

IMPLICATIONS OF THE HYPOTHESIS

By integrating the environment into the gene selection process, we expect that our strategy will improve the ability to identify the joint effects and interactions of environmental and genetic factors in disease.

Frequency of polymorphism -262 c/t in catalase gene and oxidative damage in Slovak children with bronchial asthma

INTRODUCTION

Bronchial asthma is a complex disease in which genetic factors, environmental factors and oxidative damage are responsible for the initiation and modulation of disease progression. If antioxidant mechanisms fail, reactive oxygen species damage the biomolecules followed by progression of the disease. Catalase is one of the most important endogenous enzymatic antioxidants. In the present study, we examined the hypothesis that increased oxidative damage and polymorphism in the CAT gene (-262 promoter region, C/T) are associated with childhood bronchial asthma.

PATIENTS AND METHODS

Genotyping of the polymorphisms in the CAT gene in healthy (249) and asthmatic children (248) was performed using polymerase chain reaction-restriction fragment length polymorphism. Markers of oxidative damage: content of sulfhydryl groups and thiobarbituric acid-reactive substances were determined by spectrophotometry in children.

RESULTS

The TT genotype of catalase was more frequent among the asthmatic patients (22.6%) than in healthy children (4.8%) (odds ratio=5.63; 95% confidence interval=2.93-10.81, P<.001). The amount of sulfhydryl groups decreased significantly and conversely, the content of thiobarbituric acid-reactive substances increased significantly in bronchial asthma and in catalase TT genotype compared to other catalase genotypes of this gene.

CONCLUSIONS

These results suggest that catalase polymorphism might participate in development of bronchial asthma and in enhanced oxidative damage in asthmatic children. Genetic variation of enzymatic antioxidants may modulate disease risk.

PM2.5, oxidant defence and cardiorespiratory health: a review

Airborne fine particle mass concentrations (PM2.5) are used for ambient air quality management worldwide based in part on known cardiorespiratory health effects. While oxidative stress is generally thought to be an important mechanism in determining these effects, relatively few studies have specifically examined how oxidant defence may impact susceptibility to particulate air pollution. Here we review studies that explore the impact of polymorphisms in anti-oxidant related genes or anti-oxidant supplementation on PM2.5-induced cardiorespiratory outcomes in an effort to summarize existing evidence related to oxidative stress defence and the health effects of PM2.5. Recent studies of PM-oxidative burden were also examined. In total, nine studies were identified and reviewed and existing evidence generally suggests that oxidant defence may modify the impact of PM2.5 exposure on various health outcomes, particularly heart rate variability (a measure of autonomic function) which was the most common outcome examined in the studies reviewed. Few studies examined interactions between PM2.5 and oxidant defence for respiratory outcomes, and in general studies focused primarily on acute health effects. Therefore, further evaluation of the potential modifying role of oxidant defence in PM2.5-induced health effects is required, particularly for chronic outcomes. Similarly, while an exposure metric that captures the ability of PM2.5 to cause oxidative stress may offer advantages over traditional mass concentration measurements, little epidemiological evidence is currently available to evaluate the potential benefits of such an approach. Therefore, further evaluation is required to determine how this metric may be incorporated in ambient air quality management.

Systemic levels of ceruloplasmin oxidase activity in allergic asthma and allergic rhinitis

CONTEXT

The role of ceruloplasmin oxidase activity (COA) involving the interaction of oxidant and antioxidant balance in allergic diseases is still unknown.

OBJECTIVE

Our study was designed to examine the changes in COAs in severe persistent asthma-allergic rhinitis, new diagnosed allergic asthma-allergic rhinitis and allergic rhinitis patients.

METHODS

The study included 20 age- and sex-matched healthy individuals as control (Group I); Group II included 15 newly diagnosed allergic asthma-allergic rhinitis; Group III included 15 patients with severe persistent asthma-allergic rhinitis and in the fourth group there were 20 patients with allergic rhinitis. Group III was divided in two groups, severe persistent asthma-allergic rhinitis who were pre-(III-A) and post-treated (III-B) with omalizumab. Group IV was divided to two groups, pretreatment (IV-A) and posttreatment (IV-B) with specific subcutaneous immunotherapy modalities. All the posttreatment measurements were 12 months after the therapy. All the patients were assessed by the skin prick test, high sensitive C-reactive protein (hs-CRP) and COA.

RESULTS

There were significant differences between Group I and Groups III-A, III-B, IV-A and IV-B; Group II and Groups III-A, III-B, IV-A and IV-B; Group III-A and Groups III-B, IV-A and IV-B; Group III-A and Groups IV-A and IV-B; and Group IV-A and IV-B. Interestingly, there was a correlation between the hs-CRP and COA levels in Group III-A.

CONCLUSIONS

Our data suggest that hs-CRP and COA levels might be an indicator of an inflammation and important in revelation of patients with allergy related diseases, especially of asthma patients.

Dysferlin and animal models for dysferlinopathy

Dysferlin (DYSF) is involved in the membrane-repair process, in the intracellular vesicle system and in T-tubule development in skeletal muscle. It interacts with mitsugumin 53, annexins, caveolin-3, AHNAK, affixin, S100A10, calpain-3, tubulin and dihydropyridine receptor. Limb-girdle muscular dystrophy 2B (LGMD2B) and Miyoshi myopathy (MM) are muscular dystrophies associated with recessively inherited mutations in the DYSF gene. The diseases are characterized by weakness and muscle atrophy that progress slowly and symmetrically in the proximal muscles of the limb girdles. LGMD2B and MM, which are collectively termed “dysferlinopathy”, both lead to abnormalities in vesicle traffic and membrane repair at the plasma membrane in muscle fibers. SJL/J (SJL) and A/J mice are naturally occurring animal models for dysferlinopathy. Since there has been no an approach to therapy for dysferlinopathy, the immediate development of a therapeutic method for this genetic disorder is desirable. The murine models are useful in verification experiments for new therapies and they are valuable tools for identifying factors that accelerate dystrophic changes in skeletal muscle. It could be possible that the genetic or immunological background in SJL or A/J mice could modify muscle damage in experiments involving these models, because SJL and A/J mice show differences in the progress and prevalent sites of skeletal muscle lesions as well as in the gene-expression profiles of their skeletal muscle. In this review, we provide up-to-date information on the function of dysferlin, the development of possible therapies for muscle dystrophies (including dysferlinopathy) and the detection of new therapeutic targets for dysferlinopathy by means of experiments using animal models for dysferlinopathy.

Genomics and the respiratory effects of air pollution exposure

Adverse health effects from air pollutants remain important, despite improvement in air quality in the past few decades. The exact mechanisms of lung injury from exposure to air pollutants are not yet fully understood. Studying the genome (e.g. single-nucleotide polymorphisms (SNP) ), epigenome (e.g. methylation of genes), transcriptome (mRNA expression) and microRNAome (microRNA expression) has the potential to improve our understanding of the adverse effects of air pollutants. Genome-wide association studies of SNP have detected SNP associated with respiratory phenotypes; however, to date, only candidate gene studies of air pollution exposure have been performed. Changes in epigenetic processes, such DNA methylation that leads to gene silencing without altering the DNA sequence, occur with air pollutant exposure, especially global and gene-specific methylation changes. Respiratory cell line and animal models demonstrate distinct gene expression signatures in the transcriptome, arising from exposure to particulate matter or ozone. Particulate matter and other environmental toxins alter expression of microRNA, which are short non-coding RNA that regulate gene expression. While it is clearly important to contain rising levels of air pollution, strategies also need to be developed to minimize the damaging effects of air pollutant exposure on the lung, especially for patients with chronic lung disease and for people at risk of future lung disease. Careful study of genomic responses will improve our understanding of mechanisms of lung injury from air pollution and enable future clinical testing of interventions against the toxic effects of air pollutants.

Association study of genes associated to asthma in a specific environment, in an asthma familial collection located in a rural area influenced by different industries

Eight candidate genes selected in this study were previously associated with gene-environment interactions in asthma in an urban area. These genes were analyzed in a familial collection from a founder and remote population (Saguenay-Lac-Saint-Jean; SLSJ) located in an area with low air levels of ozone but with localized areas of relatively high air pollutant levels, such as sulphur dioxide, when compared to many urban areas. Polymorphisms (SNPs) were extracted from the genome-wide association study (GWAS) performed on the SLSJ familial collection. A transmission disequilibrium test (TDT) was performed using the entire family sample (1,428 individuals in 254 nuclear families). Stratification according to the proximity of aluminium, pulp and paper industries was also analyzed. Two genes were associated with asthma in the entire sample before correction (CAT and NQO1) and one was associated after correction for multiple analyses (CAT). Two genes were associated when subjects were stratified according to the proximity of aluminium industries (CAT and NQO1) and one according to the proximity of pulp and paper industries (GSTP1). However, none of them resisted correction for multiple analyses. Given that the spatial pattern of environmental exposures can be complex and inadequately represented by a few stationary monitors and that exposures can also come from sources other than the standard outdoor air pollution (e.g., indoor air, occupation, residential wood smoke), a new approach and new tools are required to measure specific and individual pollutant exposures in order to estimate the real impact of gene-environment interactions on respiratory health.

Air pollution and health: emerging information on susceptible populations

Outdoor air pollution poses risks to human health in communities around the world, and research on populations who are most susceptible continues to reveal new insights. Human susceptibility to adverse health effects from exposure to air pollution can be related to underlying disease; demographic or anthropometric characteristics; genetic profile; race and ethnicity; lifestyle, behaviors, and socioeconomic position; and location of residence or daily activities. In health research, an individual or group may have an enhanced responsiveness to a given, identical level of pollution exposure compared to those who are less susceptible. Or, people in these different groups may experience varying levels of exposure (for example, a theoretically homogeneous population whose members differ only by proximity to a road). Often the information available for health research may relate to both exposure and enhanced response to a given dose of pollution. This paper discusses the general direction of research on susceptibility to air pollution, with a general though not an exclusive focus on particulate matter, with specific examples of research on susceptibility related to cardiovascular disease, diabetes, asthma, and genetic and epigenetic features. We conclude by commenting how emerging knowledge of susceptibility can inform policy for controlling pollution sources and exposures to yield maximal health benefit and discuss two areas of emerging interest: studying air pollution and its connection to perinatal health, as well as land use and urban infrastructure design.

Heme oxygenase-1 promoter polymorphism is associated with risk of malignant mesothelioma

BACKGROUND

Malignant mesothelioma is an aggressive tumor of serosal surfaces that is closely associated with asbestos exposure which induces oxidative stress. Heme oxygenase (HO)-1, a rate-limiting enzyme of heme degradation, plays a protective role against oxidative stress. The HO-1 gene promoter carries (GT)n repeats whose number is inversely related to transcriptional activity of the HO-1 gene.

METHODS

To investigate the relationship between the length polymorphism of (GT)n repeats and mesothelioma susceptibility, we analyzed the HO-1 promoter in 44 asbestos-exposed subjects without mesothelioma and 78 asbestos-exposed subjects with mesothelioma using PCR-based genotyping.

RESULTS

The number of repeats ranged from 16 to 38, with two peaks at 23 and 30 repeats. Polymorphisms of (GT)n repeats were grouped into two classes of alleles, short (S) (<24) and long (L) (≥24), and three genotypes: L/L, L/S, and S/S. The proportions of allele frequencies in class L as well as genotypic frequencies of L allele carriers (L/L and L/S) were significantly higher in the asbestos-exposed subjects with mesothelioma than in those without mesothelioma.

CONCLUSION

The findings of this study suggest that long (GT)n repeats in the HO-1 gene promoter are associated with a higher risk of malignant mesothelioma in the Japanese population.

High prevalence of childhood asthma in Northern Israel is linked to air pollution by particulate matter: evidence from GIS analysis and Bayesian Model Averaging

The medical records of 3922 school children residing in the Greater Haifa Metropolitan Area in Northern Israel were analyzed. Individual exposure to ambient air pollution (SO(2) and PM(10)) for each child was estimated using Geographic Information Systems tools. Factors affecting childhood asthma risk were then investigated using logistic regression and the more recently developed Bayesian Model Averaging (BMA) tools. The analysis reveals that childhood asthma in the study area appears to be significantly associated with particulate matter of less than 10 μm in aerodynamic diameter (PM(10)) (Odds Ratio (OR) = .11; P<0.001). However, no significant association with asthma prevalence was found for SO(2) (P >0.2), when PM(10) and SO(2) were introduced into the models simultaneously. When considering a change in PM(10) between the least and the most polluted parts of the study area (9.4 μg/m(3)), the corresponding OR, calculated using the BMA analysis, is 2.58 (with 95% posterior probability limits of OR ranging from 1.52 to 4.41), controlled for gender, age, proximity to main roads, the town of a child's residence, and family's socio-economic status. Thus, it is concluded that exposure to airborne particular matter, even at relatively low concentrations (40-50 μg/m(3)), generally below international air pollution standards (55-70 μg/m(3)), appears to be a considerable risk factor for childhood asthma in urban areas. This should be a cause of concern for public health authorities and environmental decision-makers.