Biomarkers of the health outcomes associated with ambient particulate matter exposure

Associations between fine particulate matter, gene expression, and promoter methylation in human bronchial epithelial cells exposed within a classroom under air-liquid interface

Associations between indoor air pollution from fine particulate matter (PM with aerodynamic diameter dp < 2.5 μm) and human health are poorly understood. Here, we analyse the concentration-response curves for fine and ultrafine PM, the gene expression, and the methylation patterns in human bronchial epithelial cells (BEAS-2B) exposed at the air-liquid interface (ALI) within a classroom in downtown Rome. Our results document the upregulation of aryl hydrocarbon receptor (AhR) and genes associated with xenobiotic metabolism (CYP1A1 and CYP1B1) in response to single exposure of cells to fresh urban aerosols at low fine PM mass concentrations within the classroom. This is evidenced by concentrations of ultrafine particles (UFPs, dp < 0.1 μm), polycyclic aromatic hydrocarbons (PAH), and ratios of black carbon (BC) to organic aerosol (OA). Additionally, an interleukin 18 (IL-18) down-regulation was found during periods of high human occupancy. Despite the observed gene expression dysregulation, no changes were detected in the methylation levels of the promoter regions of these genes, indicating that the altered gene expression is not linked to changes in DNA methylation and suggesting the involvement of another epigenetic mechanism in the gene regulation. Gene expression changes at low exposure doses have been previously reported. Here, we add the possibility that lung epithelial cells, when singly exposed to real environmental concentrations of fine PM that translate into ultra-low doses of treatment, may undergo epigenetic alteration in the expression of genes related to xenobiotic metabolism. Our findings provide a perspective for future indoor air quality regulations. We underscore the potential role of indoor UFPs as carriers of toxic molecules with low-pressure weather conditions, when rainfall and strong winds may favour low levels of fine PM.

Methylomic, Proteomic, and Metabolomic Correlates of Traffic-Related Air Pollution in the Context of Cardiorespiratory Health: A Systematic Review, Pathway Analysis, and Network Analysis

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead to cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease and highlight contemporary challenges and opportunities associated with such efforts.

MicroRNAs as Potential Biomarkers of Environmental Exposure to Polycyclic Aromatic Hydrocarbons and Their Link with Inflammation and Lung Cancer

Exposure to atmospheric air pollution containing volatile organic compounds such as polycyclic aromatic hydrocarbons (PAHs) has been shown to be a risk factor in the induction of lung inflammation and the initiation and progression of lung cancer. MicroRNAs (miRNAs) are small single-stranded non-coding RNA molecules of ~20-22 nucleotides that regulate different physiological processes, and their altered expression is implicated in various pathophysiological conditions. Recent studies have shown that the regulation of gene expression of miRNAs can be affected in diseases associated with outdoor air pollution, meaning they could also be useful as biomarkers of exposure to environmental pollution. In this article, we review the published evidence on miRNAs in relation to exposure to PAH pollution and discuss the possible mechanisms that may link these compounds with the expression of miRNAs.

Methylomic, proteomic, and metabolomic correlates of traffic-related air pollution: A systematic review, pathway analysis, and network analysis relating traffic-related air pollution to subclinical and clinical cardiorespiratory outcomes

A growing body of literature has attempted to characterize how traffic-related air pollution (TRAP) affects molecular and subclinical biological processes in ways that could lead to cardiorespiratory disease. To provide a streamlined synthesis of what is known about the multiple mechanisms through which TRAP could lead cardiorespiratory pathology, we conducted a systematic review of the epidemiological literature relating TRAP exposure to methylomic, proteomic, and metabolomic biomarkers in adult populations. Using the 139 papers that met our inclusion criteria, we identified the omic biomarkers significantly associated with short- or long-term TRAP and used these biomarkers to conduct pathway and network analyses. We considered the evidence for TRAP-related associations with biological pathways involving lipid metabolism, cellular energy production, amino acid metabolism, inflammation and immunity, coagulation, endothelial function, and oxidative stress. Our analysis suggests that an integrated multi-omics approach may provide critical new insights into the ways TRAP could lead to adverse clinical outcomes. We advocate for efforts to build a more unified approach for characterizing the dynamic and complex biological processes linking TRAP exposure and subclinical and clinical disease, and highlight contemporary challenges and opportunities associated with such efforts.

Ambient ultrafine particle (PM0.1): Sources, characteristics, measurements and exposure implications on human health

The problem of ultrafine particles (UFPs; PM_0.1) has been prevalent since the past decades. In addition to become easily inhaled by human respiratory system due to their ultrafine diameter (<100 nm), ambient UFPs possess various physicochemical properties which make it more toxic. These properties vary based on the emission source profile. The current development of UFPs studies is hindered by the problem of expensive instruments and the inexistence of standardized measurement method. This review provides detailed insights on ambient UFPs sources, physicochemical properties, measurements, and estimation models development. Implications on health impacts due to short-term and long-term exposure of ambient UFPs are also presented alongside the development progress of potentially low-cost UFPs sensors which can be used for future UFPs studies references. Current challenge and future outlook of ambient UFPs research are also discussed in this review. Based on the review results, ambient UFPs may originate from primary and secondary sources which include anthropogenic and natural activities. In addition to that, it is confirmed from various chemical content analysis that UFPs carry heavy metals, PAHs, BCs which are toxic in its nature. Measurement of ambient UFPs may be performed through stationary and mobile methods for environmental profiling and exposure assessment purposes. UFPs PNC estimation model (LUR) developed from measurement data could be deployed to support future epidemiological study of ambient UFPs. Low-cost sensors such as bipolar ion and ionization sensor from common smoke detector device may be further developed as affordable instrument to monitor ambient UFPs. Recent studies indicate that short-term exposure of UFPs can be associated with HRV change and increased cardiopulmonary effects. On the other hand, long-term UFPs exposure have positive association with COPD, CVD, CHF, pre-term birth, asthma, and also acute myocardial infarction cases.

Dust fall PM2.5-induced lung inflammation in rats is associated with hypermethylation of the IFN-γ gene promoter via the PI3K-Akt-DNMT3b pathway

Inflammation is one of the major adverse effects of fine particulate matter (PM_2.5) on the lung system; however, its mechanisms remain unclear. Rats were exposed to different concentrations of PM_2.5 to investigate the mechanism of short-term exposure-induced lung inflammation. The regulation of PI3K-Akt and DNA methyltransferase 3b (DNMT3b) was assessed by using a PI3K inhibitor and a DNA methyltransferase inhibitor. We found that PM_2.5 could decrease interferon-γ (IFN-γ) levels and increase interleukin 4 (IL-4), IL-5 and IL-13 levels in bronchoalveolar lavage fluid (BALF) to promote eosinophil infiltration and eventually lead to allergic pulmonary inflammation. Moreover, the CpG island methylation rate of the IFN-γ promoter and the protein expression of DNMT3b, PI3K and p-Akt were increased in lung tissues after PM_2.5 exposure. Both inhibitors reversed the CpG island hypermethylation of IFN-γ. In conclusion, in PM_2.5-induced lung injury, the activated PI3K-Akt pathway, via an increase in DNMT3b expression, is involved in CpG hypermethylation of the IFN-γ gene promoter.

Status of TNF-α and IL-6 as pro-inflammatory cytokines in exhaled breath condensate of late adolescents with asthma and healthy in the dust storm and non-dust storm conditions

Exposure to airborne particulate matter (PM) can be considered as an important risk factor for human health. Some cytokines have been recognized as the biomarkers of exposure to air pollution. Experimental studies indicate that PM exposure could be associated with inflammation. Thus, the purpose of this study was to evaluate whether the exposure to air PM is associated with biomarkers of inflammation. The specific aim of this study was to determine the correlation between airborne PM levels and IL-6 and TNF-α as airway inflammation biomarkers among two groups of late adolescents in northwest of Iran. This study included 46 subjects, comprising 23 asthmatic subjects and 23 non-asthmatic persons. Environmental PM (PM₁₀, PM_2.5 and PM₁) levels were measured in dust storm and non-dust storm days during both cold and warm seasons. Following the sampling of PM, Two pro-inflammatory cytokines of IL-6 and TNF-α in exhaled breath condensate (EBC) were also determined in the EBC samples via commercial ELISA kits. Daily mean ambient air PM₁₀, PM_2.5 and PM₁ concentrations during the dust storm days was 221.79, 93.13 and 25.52 μg m^-3 and in non-dusty days 48.37, 18.54 and 6.1 μg m^-3, respectively. Biomarkers levels were significantly (p < 0.001) higher in asthmatic students compared to the non-asthmatic subjects. EBC cytokines levels were increased in dust storm days compared to the non-dusty days (p < 0.001) and were positively correlated with different size of ambient PM concentration. Dust storm conditions can increase the pro-inflammatory cytokines and cause adverse effects on pulmonary health and lung tissue damage.

Fine and ultrafine airborne PM influence inflammation response of young adults and toxicological responses in vitro

Little evidence is available regarding the impact of different sizes of inhaled particulate matter (PM) on inflammatory responses in healthy young adults in connection with toxicological responses. We conducted a five-time repeated measurement panel study on 88 healthy young college students in Guangzhou, China from December 2017 to January 2018. Blood samples were collected from each participant and tested for tumor necrosis factor alpha (TNF-α) levels every week for 5 consecutive weeks. Mass concentrations of ambient PM_2.5, PM₁, PM_0.5 and number concentrations of ambient PM_0.1 were measured. RAW 264.7 macrophages were exposed to PM (PM_10-2.5, PM_2.5-1, PM_1-0.2, PM_0.2) collected at the same time as the panel study. Cytotoxicity, oxidation and inflammatory parameters, cell cycle and genotoxicity were tested. Particles were characterized for their chemical composition. The trends of associations between PM_2.5, PM₁, PM_0.5 and TNF-α level were consistent in lag 0 and 3 days, and the relative risk decreased as the particle size decreased. All the ambient air pollutants had the similar change trends in lag 1, 4 and 5 days. Similar results in RAW 264.7 macrophages were found; PM_10-2.5 induced the greatest TNF-α and macrophage inflammatory protein 2 (MIP-2) productions and oxidative damage. PM_1-0.2 and PM_0.2 induced more significant dose-dependent increases of cell cycle and genotoxic response. In the component concentrations of PM samples, metal elements were PM_10-2.5 > PM_2.5-1 > PM_0.2 ≥ PM_1-0.2; ions and polycyclic aromatic hydrocarbons (PAHs) were PM_0.2 > PM_1-0.2 > PM_2.5-1 > PM_10-2.5. Our results suggested that exposure to all particle sizes was significantly associated with inflammation among healthy young adults and toxicological responses in RAW 264.7 macrophages. Different human and toxicological reactions caused by PM samples indicated the importance of investigating various particle sizes.

Inflammation resolution in environmental pulmonary health and morbidity

Inflammation and resolution are dynamic processes comprised of inflammatory activation and neutrophil influx, followed by mediator catabolism and efferocytosis. These critical pathways ensure a return to homeostasis and promote repair. Over the past decade research has shown that diverse mediators play a role in the active process of resolution. Specialized pro-resolving mediators (SPMs), biosynthesized from fatty acids, are released during inflammation to facilitate resolution and are deficient in a variety of lung disorders. Failed resolution results in remodeling and cellular deposition through pro-fibrotic myofibroblast expansion that irreversibly narrows the airways and worsens lung function. Recent studies indicate environmental exposures may perturb and deregulate critical resolution pathways. Environmental xenobiotics induce lung inflammation and generate reactive metabolites that promote oxidative stress, injuring the respiratory mucosa and impairing gas-exchange. This warrants recognition of xenobiotic associated molecular patterns (XAMPs) as new signals in the field of inflammation biology, as many environmental chemicals generate free radicals capable of initiating the inflammatory response. Recent studies suggest that unresolved, persistent inflammation impacts both resolution pathways and endogenous regulatory mediators, compromising lung function, which over time can progress to chronic lung disease. Chronic ozone (O3) exposure overwhelms successful resolution, and in susceptible individuals promotes asthma onset. The industrial contaminant cadmium (Cd) bioaccumulates in the lung to impair resolution, and recurrent inflammation can result in chronic obstructive pulmonary disease (COPD). Persistent particulate matter (PM) exposure increases systemic cardiopulmonary inflammation, which reduces lung function and can exacerbate asthma, COPD, and idiopathic pulmonary fibrosis (IPF). While recurrent inflammation underlies environmentally induced pulmonary morbidity and may drive the disease process, our understanding of inflammation resolution in this context is limited. This review aims to explore inflammation resolution biology and its role in chronic environmental lung disease(s).

Ambient air pollutants increase the risk of immunoglobulin E-mediated allergic diseases: a systematic review and meta-analysis

Immunoglobulin E (IgE)-mediated allergic diseases, including eczema, atopic dermatitis (AD), and allergic rhinitis (AR), have increased prevalence in recent decades. Recent studies have proved that environmental pollution might have correlations with IgE-mediated allergic diseases, but existing research findings were controversial. Thus, we performed a comprehensive meta-analysis from published observational studies to evaluate the risk of long-term and short-term exposure to air pollutants on eczema, AD, and AR in the population (per 10-μg/m3 increase in PM2.5 and PM10; per 1-ppb increase in SO2, NO2, CO, and O3). PubMed, Embase, and Web of Science were searched to identify qualified literatures. The Cochran Q test was used to assess heterogeneity and quantified with the I2 statistic. Pooled effects and the 95% confidence intervals (CIs) were used to evaluate outcome effects. A total of 55 articles were included in the study. The results showed that long-term and short-term exposure to PM10 increased the risk of eczema (PM10, RRlong = 1.583, 95% CI: 1.328, 1.888; RRshort = 1.006, 95% CI: 1.003-1.008) and short-term exposure to NO2 (RRshort = 1.009, 95% CI: 1.008-1.011) was associated with eczema. Short-term exposure to SO2 (RRshort: 1.008, 95% CI: 1.001-1.015) was associated with the risk of AD. For AR, PM2.5 (RRlong = 1.058, 95% CI: 1.014-1.222) was harmful in the long term, and short-term exposure to PM10 (RRshort: 1.028, 95% CI: 1.008-1.049) and NO2 (RRshort: 1.018, 95% CI: 1.007-1.029) were risk factors. The findings indicated that exposure to air pollutants might increase the risk of IgE-mediated allergic diseases. Further studies are warranted to illustrate the potential mechanism for air pollutants and allergic diseases.

Chronic Pesticide Exposure in Farm Workers Is Associated with the Epigenetic Modulation of hsa-miR-199a-5p

The increasing use of pesticides in intensive agriculture has had a negative impact on human health. It was widely demonstrated how pesticides can induce different genetic and epigenetic alterations associated with the development of different diseases, including tumors and neurological disorders. Therefore, the identification of effective indicators for the prediction of harmful pesticide exposure is mandatory. In this context, the aim of the study was to evaluate the modification of hsa-miR-199a-5p expression levels in liquid biopsy samples obtained from healthy donors and farm workers with chronic exposure to pesticides. For this purpose, the high-sensitive droplet digital PCR assay (ddPCR) was used to detect variation in the expression levels of the selected microRNA (miRNA). The ddPCR analyses revealed a significant down-regulation of hsa-miR-199a-5p observed in individuals exposed to pesticides compared to control samples highlighting the good predictive value of this miRNA as demonstrated by statistical analyses. Overall, the obtained results encourage the analysis of miRNAs as predictive biomarkers of chronic pesticide exposure thus improving the current strategies for the monitoring of harmful pesticide exposure.

Associations between differences in anemia-related blood cell parameters and short-term exposure to ambient particle pollutants in middle-aged and elderly residents in Beijing, China

Anemia is a highly prevalent disease among older populations, with multiple adverse health outcomes, and particles exposure is a potential risk factor for anemia. However, evidence on associations of exposure to particles with small size with anemia-related blood cell parameters levels in the elderly is limited, and the underlying mechanisms are unclear. Based on a panel study in Beijing, we found that in 135 elderly participants, mass concentrations of particle with an aerodynamic diameter ≤ 2.5 μm (PM_2.5), black/elemental carbon (BC/EC, particle size range: 0-2.5 μm), and number concentrations of ultrafine particles (UFPs, particle size range: 5.6-93.1 nm) and accumulated mode particles (Acc, size range: 93.1-560 nm) were significantly associated with levels of red blood cell count (RBC), hemoglobin (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC). The mean ± SD for PM_2.5, UFPs, Acc, BC, OC, and EC were 69.7 ± 61.1 μg/m³, 12.5 ± 4.3 × 10³/cm³, 1.6 ± 1.2 × 10³/cm³, 3.0 ± 2.0 μg/m³, 8.7 ± 6.7 μg/m³, and 2.1 ± 1.6 μg/m³, respectively. Cotinine (higher than 50 ng/mL) is used as an indicator of smoking exposure. The association between MCHC difference and per interquartile range (IQR) increase in average UFPs concentration 14 d before clinical visits was -0.7% (95% CI: -1.1% to -0.3%). Significant associations of UFPs and Acc exposure with MCHC and MCH levels remain robust after adjustment for other pollutants. Furthermore, 25.2% (95% CI: 7.4% to 64.8%) and 29.8% (95% CI: 5.3% to 214.4%) of the difference in MCHC associated with average UFPs and Acc concentrations 14 d before clinical visits were mediated by the level of tumor necrosis factor α (TNF α), a biomarker of systemic inflammation. Our findings for the first time provide the evidence that short-term UFPs and Acc exposure contributed to the damage of anemia-related blood cell in the elderly, and systemic inflammation was a potential internal mediator.

Inequalities in occupational exposures among people using popular commute modes

Several recent studies have looked into the differences in air qualities inside popular commute modes. The impact of daily commuting patterns and work-related trips on inhalation doses, however, are not investigated. The purpose of this study is to quantify the variation in air pollutants within popular commute modes in Mumbai, India, and to estimate the variation in exposure as a result of occupational or work-related trips across different sub-groups. Real-time pollutants, both gaseous and particulate matters (PM), were measured on a pre-defined route during rush and non-rush hours on buses, cars, auto-rickshaws, sub-urban trains, and motorbikes through several trips (N = 98). Household surveys were conducted to estimate the exposures of different occupational subgroups (cab-driver, auto-rickshaw drivers, delivery persons) and people commuting to their offices daily. Participants (N = 800) from various socioeconomic backgrounds in the city were asked about their job categories, work-activity patterns, and work-related commute trips. Mass concentrations of particles in different size ranges (PM₁, PM_2.5, and PM₁₀) were substantially higher (p < 0.05) inside auto-rickshaws (44.6 μg/m³, 84.7 μg/m³, and 138.3 μg/m³) compared to other modes. Inside cars, gaseous pollutants such as carbon monoxide (CO) and total volatile organic compounds (TVOC) were significantly higher (p < 0.05). Although both gaseous and particulate concentrations were lower (p < 0.05) inside buses, bus-commuters were found to be highly exposed to the pollutants due to the extended trip time (∼1.2 times longer than other modes) and driving conditions. Office commuters inhale a large fraction of their daily doses (25-30%) during their work-related travel. Occupational sub-groups, on the other hand, inhale ∼90% of the pollutants during their work. In a day, an auto-rickshaw driver inhales 10-15% more (p < 0.05) pollutants than cab driver or delivery personnel. Therefore, this study highlights the inequalities in occupational exposure as a combined effect of in-cabin air qualities and commute patterns due to occupational obligations.

Biomarkers for the adverse effects on respiratory system health associated with atmospheric particulate matter exposure

Large amounts of epidemiological evidence have confirmed the atmospheric particulate matter (PM_2.5) exposure was positively correlated with the morbidity and mortality of respiratory diseases. Nevertheless, its pathogenesis remains incompletely understood, probably resulting from the activation of oxidative stress, inflammation, altered genetic and epigenetic modifications in the lung upon PM_2.5 exposure. Currently, biomarker investigations have been widely used in epidemiological and toxicological studies, which may help in understanding the biologic mechanisms underlying PM_2.5-elicited adverse health outcomes. Here, the emerging biomarkers to indicate PM_2.5-respiratory system interactions were summarized, primarily related to oxidative stress (ROS, MDA, GSH, etc.), inflammation (Interleukins, FE_NO, CC16, etc.), DNA damage (8-OHdG, γH2AX, OGG1) and also epigenetic modulation (DNA methylation, histone modification, microRNAs). The identified biomarkers shed light on PM_2.5-elicited inflammation, fibrogenesis and carcinogenesis, thus may favor more precise interventions in public health. It is worth noting that some inconsistent findings may possibly relate to the inter-study differentials in the airborne PM_2.5 sample, exposure mode and targeted subjects, as well as methodological issues. Further research, particularly by -omics technique to identify novel, specific biomarkers, is warranted to illuminate the causal relationship between PM_2.5 pollution and deleterious lung outcomes.

Prenatal particulate matter exposure and mitochondrial mutational load at the maternal-fetal interface: Effect modification by genetic ancestry

Prenatal ambient particulate matter (PM2.5) exposure impacts infant development and alters placental mitochondrial DNA abundance. We investigated whether the timing of PM2.5 exposure predicts placental mitochondrial mutational load using NextGen sequencing in 283 multi-ethnic mother-infant dyads. We observed increased PM2.5exposure, particularly during mid- to late-pregnancy and among genes coding for NADH dehydrogenase and subunits of ATP synthase, was associated with a greater amount of nonsynonymous mutations. The strongest associations were observed for participants of African ancestry. Further work is needed to tease out the role of mitochondrial genetics and its impact on offspring development and emerging disease disparities.

Acute responses of airway oxidative stress, inflammation, and hemodynamic markers to ambient PM2.5 and their trace metal contents among healthy adolescences: A panel study in highly polluted versus low polluted regions

Particulate air pollutants are known contributors to global cardiorespiratory mortality through several pathways. We examined the effects of varied exposure to PM_2.5 and trace metals on biological markers of airway inflammation, oxidative stress, and hemodynamic function of young individuals living in two different exposure settings. We enrolled and followed a panel of 97 healthy nonsmoking participants aged 15-18 years living in a highly polluted metropolitan city of Tabriz (TBZ) and a much less polluted semi-urban town of Hadishahr (HDS). For five consecutive months, the subjects were examined by a physician, and fractional exhaled nitric oxide levels (FE_NO) were measured. Samples of exhaled breath condensation (EBC) were obtained for measuring interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), and total nitric oxide (NO_x). We measured daily outdoor PM_2.5 mass concentration in a fixed station in each location for all this period. The PM-metal content was analyzed by ICP-MS. The linear mixed-effects regression models were applied for data analysis. The averages of PM_2.5 mass and total metals in TBZ were nearly two and four times higher than in HDS, respectively. In TBZ, an increased IQR of PM_2.5 mass during 0-5 days was -correlated with a significant rise in diastolic blood pressure, heart rate, TNF-α, FE_NO, and NO_x and reduction of IL-6. Moreover, exposure to low PM_2.5 concentration is significantly -correlated with an elevation in diastolic blood pressure in HDS. We also observed that exposure to metal constituents in the highly polluted region is correlated with increased TNF-α and IL-6 with 131.80% (95% CI: 56.01, 244.39) and 47.51% (95% CI: 33.01, 62.05) per IQR of Hg, respectively. This study suggests that exposure to ambient PM_2.5 and their metal contents in highly polluted areas may incite significant changes in airway inflammation, oxidative stress, and hemodynamic parameters in healthy subjects.

Association between exposure to different stone aggregates from asphalt and blood coagulability: A human exposure chamber study

A large fraction of particulate matter (PM)_, especially PM₁₀, concentrations are due to non-exhaust emissions, such as road abrasion and wear on tires and brake pads. Concentrating on road abrasion, we aimed to investigate blood coagulability in healthy adults after exposure to two types of stone materials commonly used in asphalt on Norwegian roads. This study followed a randomized, double-blind, cross-over study design. Using an exposure chamber, 24 healthy young volunteers were exposed to aggregates of two different types of rocks and placebo dust: quartz diorite, rhomb porphyry, and lactose (placebo dust). Each exposure session lasted for 4 hours (h), and blood samples were collected before exposure (baseline), 4 h post-exposure, and 24 h post-exposure to analyse potential changes in the von Willebrand factor (vWF) as well as of fibrinogen, d-dimer, leukocytes, and thrombocytes. The dust concentration in the exposure chamber was measured with real-time instruments and gravimetric samples of total dust, respirable dust, PM₁₀, PM_2.5, and ultrafine particles (UFP). The results were analysed using a linear mixed-effect model. Leukocyte blood counts increased post-exposure for all exposure materials; however, none of the increases were statistically significant. The concentration of fibrinogen increased after exposure to quartz diorite, while it decreased after exposures to rhomb porphyry and lactose. Type of material was a statistically significant explanatory variable for the concentration of fibrinogen, with the most significant increase occurring 24 h post-exposure to quartz diorite. After exposure to the three materials, vWF decreased. For the thrombocytes, an increase in blood count was observed 24 h post-exposure to quartz diorite and rhomb porphyry, with a modest (p = 0.09) positive association for quartz diorite. Although the results are limited, we conclude that the different effects observed post-exposure to quartz diorite support considering potential health effects when choosing materials in the production of asphalt.

Short-term personal PM2.5 exposure and change in DNA methylation of imprinted genes: Panel study of healthy young adults in Guangzhou city, China

DNA methylation (DNAm) plays a significant role in deleterious health effects inflicted by fine particulate matter (PM_2.5) on the human body. Recent studies have reported that DNAm of imprinted control regions (ICRs) in imprinted genes may be a sensitive biomarker of environmental exposure. Less is known about specific biomarkers of imprinted genes after PM_2.5 exposure. The relationship between PM_2.5 and its chemical constituents and DNAm of ICRs in imprinted genes after short-term exposure was investigated to determine specific human biomarkers of its adverse health effects. A panel study was carried out in healthy young people in Guangzhou, China. Mixed-effects models were used to evaluate the influence of PM_2.5 and its constituent exposure on DNAm while controlling for potential confounders. There was no significant correlation between DNAm and personal PM_2.5 exposure mass. DNAm changes in eight ICRs (L3MBTL1, NNAT, PEG10, GNAS Ex1A, MCTS2, SNURF/SNRPN, IGF2R, and RB1) and a non-imprinted gene (CYP1B1) were significantly associated with PM_2.5 constituents. Compared to non-imprinted genes, imprinted gene methylation was more susceptible to interference with PM_2.5 constituent exposure. Among those genes, L3MBTL1 was the most sensitive to personal PM_2.5 constituent exposure. Moreover, transition metals derived from traffic sources (Cd, Fe, Mn, and Ni) significantly influenced DNAm of the imprinted genes, suggesting the importance of more targeted measures to reduce toxic constituents. Bioinformatics analysis indicated that imprinted genes (RB1) may be correlated with pathways and diseases (non-small cell lung cancer, glioma, and bladder cancer). The present study suggests that screening the imprinted gene for DNAm can be used as a sensitive biomarker of PM_2.5 exposure. The results will provide data for prevention of PM_2.5 exposure and a novel perspective on potential mechanisms on an epigenetic level.

Particulate matter exposure and biomarkers associated with blood coagulation: A meta-analysis

OBJECTIVE

Find the correlation between particulate matter (PM) and biomarkers related to blood coagulation, offer medical evidence to sensitive indicators and carry out early diagnosis of cardiovascular diseases.

METHOD

A combination of computer and manual retrieval was used to search for the keywords in PubMed (584 records), Cochrane Library (28 records), Web of Science (162 records) and Embase (163 records). Finally, a total of 25 articles were included in this meta-analysis. Stata 13.0 was applied to examine the heterogeneity among the studies and to calculate the combined effect estimates, percent variation (%) and 95% CI by selecting corresponding models. Additionally, sensitivity analysis and publication bias test were also conducted.

RESULTS

Meta-analysis indicated that there was an association between PM_2.5 exposure (per 10 µg/m³ increase) and fibrinogen. With the increase of PM_2.5 exposure (per 10 µg/m³ increase), the content of fibrinogen revealed a high level (2.26%; 95% CI: 1.08-3.44%); and the increase of UFPs exposure (per 5000/cm³ increase) was correlated with some biomarkers such as cell surface antigen and protein ligand including ICAM-1, sCD40L, P-selectin, E-selectin and PAI-1 that indirectly related to blood coagulation, yielding a percent variation of 10.83% (95% CI: 3.49%-18.17%).

CONCLUSION

This meta-analysis expounded that PM-related biomarkers were associated with blood coagulation, and the relationship with fibrinogen was much stronger.

Inflammatory cytokines and DNA methylation in healthy young adults exposure to fine particulate matter: A randomized, double-blind crossover trial of air filtration

Benefits of indoor air filtration in heavily polluted areas are not fully understood. This study aims to examine whether short-term air filtration intervention could attenuate the hazards from acute exposure to fine particulate matter (PM_2.5), and investigate the potential impact on inflammatory cytokines and DNA methylation. A randomized, double-blind crossover trial of true or sham indoor air filtration was conducted among 29 healthy young adults in Beijing, China. Each episode covered a typical air pollution wave, and 38 cytokines and DNAm of 20 genes were measured at 3 time points: pre-smog, during smog, and post-smog. Linear mixed-effect models were used to evaluate the associations. The indoor PM_2.5 concentration with true filtration was 67.8 % lower than sham filtration (13.8 μg/m³vs. 42.8 μg/m³). Air filtration was significantly associated with the decreases in 9 cytokines, from 6.61 % to 21.24 %. PM_2.5 exposure was significantly associated with elevated levels of 9 cytokines and changed methylation at 7 CpG sites. Notably, PM_2.5 was significantly associated with GM-CSF, sCD40L, MCP-1, and FGF-2, as well as methylation in corresponding genes, but no mediation effect was observed. This trial suggested that indoor air filtration might attenuate the adverse effects of PM_2.5 exposure through changing cytokines and DNAm.

The Challenge by Multiple Environmental and Biological Factors Induce Inflammation in Aging: Their Role in the Promotion of Chronic Disease

The aging process is driven by multiple mechanisms that lead to changes in energy production, oxidative stress, homeostatic dysregulation and eventually to loss of functionality and increased disease susceptibility. Most aged individuals develop chronic low-grade inflammation, which is an important risk factor for morbidity, physical and cognitive impairment, frailty, and death. At any age, chronic inflammatory diseases are major causes of morbimortality, affecting up to 5-8% of the population of industrialized countries. Several environmental factors can play an important role for modifying the inflammatory state. Genetics accounts for only a small fraction of chronic-inflammatory diseases, whereas environmental factors appear to participate, either with a causative or a promotional role in 50% to 75% of patients. Several of those changes depend on epigenetic changes that will further modify the individual response to additional stimuli. The interaction between inflammation and the environment offers important insights on aging and health. These conditions, often depending on the individual's sex, appear to lead to decreased longevity and physical and cognitive decline. In addition to biological factors, the environment is also involved in the generation of psychological and social context leading to stress. Poor psychological environments and other sources of stress also result in increased inflammation. However, the mechanisms underlying the role of environmental and psychosocial factors and nutrition on the regulation of inflammation, and how the response elicited for those factors interact among them, are poorly understood. Whereas certain deleterious environmental factors result in the generation of oxidative stress driven by an increased production of reactive oxygen and nitrogen species, endoplasmic reticulum stress, and inflammation, other factors, including nutrition (polyunsaturated fatty acids) and behavioral factors (exercise) confer protection against inflammation, oxidative and endoplasmic reticulum stress, and thus ameliorate their deleterious effect. Here, we discuss processes and mechanisms of inflammation associated with environmental factors and behavior, their links to sex and gender, and their overall impact on aging.

Biomarkers and indoor air quality: A translational research review

Introduction:

Air pollution is linked to mortality and morbidity. Since humans spend nearly all their time indoors, improving indoor air quality (IAQ) is a compelling approach to mitigate air pollutant exposure. To assess interventions, relying on clinical outcomes may require prolonged follow-up, which hinders feasibility. Thus, identifying biomarkers that respond to changes in IAQ may be useful to assess the effectiveness of interventions.

Methods:

We conducted a narrative review by searching several databases to identify studies published over the last decade that measured the response of blood, urine, and/or salivary biomarkers to variations (natural and intervention-induced) of changes in indoor air pollutant exposure.

Results:

Numerous studies reported on associations between IAQ exposures and biomarkers with heterogeneity across study designs and methods. This review summarizes the responses of 113 biomarkers described in 30 articles. The biomarkers which most frequently responded to variations in indoor air pollutant exposures were high sensitivity C-reactive protein (hsCRP), von Willebrand Factor (vWF), 8-hydroxy-2′-deoxyguanosine (8-OHdG), and 1-hydroxypyrene (1-OHP).

Conclusions:

This review will guide the selection of biomarkers for translational studies evaluating the impact of indoor air pollutants on human health.

Increase of Cardiometabolic Biomarkers Among Vehicle Inspectors Exposed to PM0.25 and Compositions

Background

Exposure to particulate matter (PM) emitted from vehicle exhaust might disrupt systemic function and elevate the risk of cardiovascular disease. In this study, we examined the changes of cardiometabolic biomarkers among vehicle inspectors exposed daily to PM0.25 and components.

Methods

This cross-sectional study was conducted at two vehicle inspection centers, Pulogadung and Ujung Menteng, located in East Jakarta, Indonesia. The exposed respondents were 43 workers from vehicle inspection centers, and the unexposed group consisted of 22 staff officers working in the same locations. Vehicle exhaust particulate matter was measured for eight hours using a Leland Legacy personal pump attached to a Sioutas Cascade Impactor. The used filters were 25 and 37-mm quartz filters. The particulate matter concentration was analyzed using a gravimetric method, whereas trace elements were analyzed using energy dispersive X-ray fluorescence. An EEL Smoke Stain Reflectometer analyzed black carbon.

Results

The personal exposure concentrations of PM0.25 were 10.4-fold higher than those in unexposed groups. Calcium and sulfur were the major components in the obtained dust, and their levels were 3.3- and 7.2-fold higher, respectively, in the exposed group. Based on an independent-samples t-test, high-density lipoprotein, triglyceride, HbA1c, total immunoglobulin E, high-sensitivity C-reactive protein, tumor necrosis factor-alpha, and nitric oxide levels were significantly different between the groups.

Conclusions

In summary, it was suggested that PM0.25 exposure from vehicle exhaust might affect cardiometabolic biomarkers change.

Effects of surrounding environment on incidence of end stage renal disease

The rising prevalence and incidence of end-stage renal disease (ESRD) have been noted around the world. However, no study has been conducted to examine the effect of surrounding environment on incidence of ESRD. This study assessed the associations of exposure to PM2.5 level and surrounding green spaces, separately, with incidence of ESRD in Taiwan. Demographic and clinical data used in this study was retrieved from the National Health Insurance Research Database from 2003 to 2012. PM2.5 data collected from the Environmental Protection Administration of Taiwan and a hybrid land-use regression model was used to approximate long-term exposure to PM2.5. Percentage of exposure to surrounding green spaces was used to determine individual exposure level. Cox proportional hazards models with a generalized estimating equation were applied to investigate the effect of surrounding environment on incidence of ESRD. The results showed significant positive association between exposure to PM2.5 level and incidence of ESRD; but inverse association between exposure to surrounding green spaces and incidence of ESRD (adjusted hazard ratio (AHR) = 1.08, 95% CI: 1.00-1.15 for exposure to PM2.5 level; AHR = 0.90, 95%CI: 0.84-0.98 for surrounding green spaces). Together, the findings from this study have added suggestive evidence on the adverse effect of exposure to PM2.5 level and the beneficial effect of exposure to surrounding green spaces on the incidence of ESRD in a general population in Taiwan.

Attributable Risk to Assess the Health Impact of Air Pollution: Advances, Controversies, State of the Art and Future Needs

Despite the increased attention given to the health impact assessment of air pollution and to the strategies to control it in both scientific literature and concrete interventions, the results of the implementations, especially those involving traffic, have not always been satisfactory and there is still disagreement about the most appropriate interventions and the methods to assess their effectiveness. This state-of-the-art article reviews the recent interpretation of the concepts that concern the impact assessment, and compares old and new measurements of attributable risk and attributable fraction. It also summarizes the ongoing discussion about the designs and methods for assessing the air pollution impact with particular attention to improvements due to spatio-temporal analysis and other new approaches, such as studying short term effects in cohorts, and the still discussed methods of predicting the values of attributable risk (AR). Finally, the study presents the more recent analytic perspectives and the methods for directly assessing the effects of not yet implemented interventions on air quality and health, in accordance with the suggestion in the strategic plan 2020-2025 from the Health Effect Institute.

Assessment of genotoxic effects on elderly populations exposed to high traffic areas: Results for supporting public health surveillance

In urban areas with intense vehicular traffic, particulate matter in suspension, especially the fraction of particles with ultra-fine diameter, has been regarded as the main problem of chronic diseases in susceptible populations, such as the elderly. This study aimed to determine the genotoxic effects of exposure to air pollution evaluating the association between the frequencies of micronuclei (MN) and binucleated (BN) cells in exfoliated oral mucosa cells of elderly population and exposure conditions, considering the influence of traffic and concentration of PM in different aerodynamic diameters. Traffic of passenger vehicles, heavy duty trucks and environmental concentrations of Particulate Matter were measured twice a day during 28 days before biological sampling of oral mucosa from 154 participants living in areas of distinct levels of urban traffic. Data from this study showed that the group of participants living near road traffic exhibited higher MN cell frequency, when compared to the other groups of subjects. In addition, a canonical correlation analysis between environmental and genotoxicity variables analysis revealed that high concentrations of the particulate matter were correlated with intense traffic and the genotoxicity in exfoliated oral cells.

Estrogen Receptor-Related DNA and Histone Methylation May Be Involved in the Transgenerational Disruption in Spermatogenesis by Selective Toxic Chemicals

Air pollution is a global threat to human health especially spermatogenesis. Animal and epidemiological studies suggest that epigenetic factors can transmit the pathologies transgenerationally. Paternal epigenetic effects can greatly impact offspring health. In this study and together with our previous report, we found that H₂S donor Na₂S and/or NH₃ donor NH₄Cl diminished mouse fertility, decreased spermatozoa concentration and motility, and impaired spermatogenesis in three consequent generations (F0, F1, and F2). In the current study, we found that DNA methylation, histone methylation, and estrogen receptor alpha (ERα) were impaired by NH₄Cl and/or Na₂S in F0, F1, and F2 mouse testes. Moreover, NH₄Cl and/or Na₂S might act as environmental endocrine-disrupting chemicals to decrease estrogen and testosterone in mouse blood. It has been reported that ERα signaling is intertwined together with DNA methylation and histone methylation, which plays very important roles in spermatogenesis. These data together indicate that the transgenerational disruption in spermatogenesis by NH₄Cl and/or Na₂S may be through ERα-related DNA methylation and histone methylation pathways. Therefore, we strongly recommend that greater attention should be paid to NH₃ and/or H₂S contamination to minimize their impact on human health especially spermatogenesis.

Air pollution associated epigenetic modifications: Transgenerational inheritance and underlying molecular mechanisms

Air pollution is one of the leading causes of deaths in Southeast Asian countries including India. Exposure to air pollutants affects vital cellular mechanisms and is intimately linked with the etiology of a number of chronic diseases. Earlier work from our laboratory has shown that airborne particulate matter disturbs the mitochondrial machinery and causes significant damage to the epigenome. Mitochondrial reactive oxygen species possess the ability to trigger redox-sensitive signaling mechanisms and induce irreversible epigenomic changes. The electrophilic nature of reactive metabolites can directly result in deprotonation of cytosine at C-5 position or interfere with the DNA methyltransferases activity to cause alterations in DNA methylation. In addition, it also perturbs level of cellular metabolites critically involved in different epigenetic processes like acetylation and methylation of histone code and DNA hypo or hypermethylation. Interestingly, these modifications may persist through downstream generations and result in the transgenerational epigenomic inheritance. This phenomenon of subsequent transfer of epigenetic modifications is mainly associated with the germ cells and relies on the germline stability of the epigenetic states. Overall, the recent literature supports, and arguably strengthens, the contention that air pollution might contribute to transmission of epimutations from gametes to zygotes by involving mitochondrial DNA, parental allele imprinting, histone withholding and non-coding RNAs. However, larger prospective studies using innovative, integrated epigenome-wide metabolomic strategy are highly warranted to assess the air pollution induced transgenerational epigenetic inheritance and associated human health effects.

PM2.5-induced alteration of DNA methylation and RNA-transcription are associated with inflammatory response and lung injury

The mechanisms of systemic pulmonary inflammation and toxicity of fine particulate matter (PM_2.5) exposure remains unclear. The current study investigated the inflammatory response and lung toxicity of PM_2.5 in rats following intratracheal instillation of PM_2.5. After repeated (treated every 3 days for 30 days) PM_2.5 exposure, total protein (TP), lactate dehydrogenase (LDH) activity and inflammatory cytokines including interleukin 6 (IL-6), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) levels in bronchoalveolar lavage fluid (BALF) were markedly elevated. The expression levels of IL-6, IL-1β, TNF-α and NF-κB in rat lung tissue and BEAS-2B cells were significantly upregulated after PM_2.5 exposure. Histopathological evaluation suggested that the major pathological changes were alveolar wall thickening and inflammatory cell infiltration of the lungs. Genome wide DNA methylation and RNA-transcription analysis was performed on human bronchial epithelial cells (BEAS-2B) to explore the potential mechanisms in vitro. PM_2.5 induced genome wide DNA methylation and transcription changes. Differentially methylated CpGs were located in gene promoter region linked with CpG islands. Integrated analysis with DNA methylation and transcription data indicated a clear bias toward transcriptional alteration by differential methylation. Disease ontology of differentially methylated and expressed genes addressed their prominent role in respiratory disease. Functional enrichment revealed their involvement in inflammation or immune response, cellular community, cellular motility, cell growth, development and differentiation, signal transduction and responses to exogenous stimuli. Gene expression validation of ACTN4, CXCL1, MARK2, ABR, PSEN1, PSMA3, PSMD1 verified their functional participation in critical biological processes and supported the microarray bioinformatics analysis. Collectively, our data shows that PM_2.5 induced genome wide methylome and transcriptome alterations that could be involved in pulmonary toxicity and pathological process of respiratory disease, providing new insight into the toxicity mechanisms of PM_2.5.

Identification of osteopontin as a biomarker of human exposure to fine particulate matter

Ambient particulate matter (PM) exposure is associated with pulmonary and cardiovascular diseases; however, there is scant research linking data on animal and human cells. The objective of this study was to investigate these associations. Vascular remodeling plays a crucial role in both pulmonary and cardiovascular diseases. Therefore, we conducted a transcriptomic analysis using vascular smooth muscle cells (VSMCs) to identify potential regulators or markers of PM exposure. We demonstrated that fine and coarse PM increased VSMC proliferation in mice. We conducted a genome-wide cDNA microarray analysis, followed by a pathway analysis of VSMCs treated with coarse PM for durations of 24, 48, and 72 h. Sixteen genes were discovered to be time-dependently upregulated and involved in VSMC proliferation. Osteopontin (OPN) is indicated as one of the regulators of these upregulated genes. Both fine and coarse PM from industrial and urban areas significantly increased OPN expression in VSMCs and macrophages. Moreover, oropharyngeal instillation of fine and coarse PM for 8 weeks increased the VSMCs in the pulmonary arteries of mice. OPN level was consistently increased in the lung tissues, bronchoalveolar lavage fluid, and serum of mice. Moreover, we analyzed the plasma OPN levels of 72 healthy participants recruited from the studied metropolitan area. Each participant wore a personal PM_2.5 sampler to assess their PM_2.5 exposure over a 24 h period. Our results indicate that personal exposure to fine PM is positively correlated with plasma OPN level in young adults. The data obtained in this study suggest that exposure to fine and coarse PM may cause pulmonary vascular lesions in humans and that OPN level may be a biomarker of PM exposure in humans.

Environmental and behavioral determinants affecting the association of airway macrophages carbon load with distance to major roads and traffic density

Biomarkers are promising indicators to evaluate human exposure to air pollutants and to predict the health outcomes. Area of Airway macrophages that is occupied by Black Carbon could be used as a biomarker of personal long term exposure to traffic related air pollution. Association of airway macrophages carbon load with weighted average distance and environmental and subject-specific behavior are considered in this study. Sputum samples were taken from 160 healthy adult women and airway macrophages carbon load (AMCL) were determined in 93 subjects, which represent a success rate of 62% in sputum induction. Nearest distance of the subjects to major roads and average weighted distance were calculated for each subject. A questionnaire was field according to general and behavioral characteristics of the participants. There was not any significant difference (P-value >0.05) between induced and non-induced subjects. Subjects with indoor kitchen without separation wall, passive smokers and those with longer presence time in high traffic streets showed higher carbon area. Weighted average distance had a better association (β = -0.186, 95%CI: -0.139, -0.230, P-value = 0.00) with AMCL than nearest distance to major roads (β = -0.155, 95%CI: -0.109, -0.201, P-value = 0.19). Association of Weighted average distance with AMCL was interrupted in subjects with a garage connected to house environment, those with IK kitchen, those with a hood above the stove and passive smokers. The findings indicated that more generation and distribution of indoor air pollutants can completely enhance the internal exposure and indoor pollution has the same importance as outdoor pollution.

MicroRNAs and their role in environmental chemical carcinogenesis

MicroRNAs (miRNAs) are a class of small, noncoding RNA species that play crucial roles across many biological processes and in the pathogenesis of major diseases, including cancer. Recent studies suggest that the expression of miRNA is altered by certain environmental chemicals, including metals, organic pollutants, cigarette smoke, pesticides and carcinogenic drugs. In addition, extensive studies have indicated the existence and importance of miRNA in different cancers, suggesting that cancer-related miRNAs could serve as potential markers for chemically induced cancers. The altered expression of miRNA was considered to be a vital pathogenic role in xenobiotic-induced cancer development. However, the significance of miRNA in the etiology of cancer and the exact mechanisms by which environmental factors alter miRNA expression remain relatively unexplored. Hence, understanding the interaction of miRNAs with environmental chemicals will provide important information on mechanisms underlying the pathogenesis of chemically induced cancers, and effectively diagnose and treat human cancers resulting from chronic or acute carcinogen exposure. This study presents the current evidence that the miRNA deregulation induced by various chemical carcinogens, different cancers caused by environmental carcinogens and the potentially related genes in the onset or progression of cancer. For each carcinogen, the specifically expressed miRNA may be considered as the early biomarkers of the cancer process. In this review, we also summarize various target genes of the altered miRNA, oncogenes or anti-oncogenes, and the existing evidence regarding the gene regulation mechanisms of cancer caused by environmentally induced miRNA alteration. The future perspective of miRNA may become attractive targets for the diagnosis and treatment of carcinogen-induced cancer.

Occupational exposure to particulate matters and telomere length

Little is known about the possible association between occupational exposure to mineral particulate matters and change in leukocyte telomere length (LTL) as a hallmark of aging. The present study studied the relationship between occupational exposures to mineral dust and LTL in the exposed group of workers and compared to non-exposed workers. One hundred and ten male workers (80 exposed and 30 non-exposed) from different units of a ceramic factory were recruited in the study. Personal air samples were collected in the breathing zone of the workers for inhalable and respirable fractions. Relative LTL was measured in blood genomic DNA using the quantitative real-time PCR method and expressed as telomere/single copy gene ratio. Exposure to inhalable and respirable dusts in the exposed group was 22.66 ± 52.38 and 2.54 ± 9.34 mg/m³ respectively. Inhalable and respirable exposure values were highly correlated (r² = 0.43; p < 0.001). Exposure to respirable and inhalable particles in 38.75% and 8.75% of exposed workers was higher than threshold limit value respectively. Mean LTL in the exposed workers (0.64 ± 0.06) was significantly shorter than the non-exposed workers (0.73 ± 0.07) (p < 0.001). Despite the significant difference in exposure intensity according to working units in the exposed group, there was no significant difference in LTL according to the working units (p = 0.60). In the adjusted regression models, but not crude models, marginally significant and positive association was found between both size fractions and LTL. The observed effect size for respirable particles was five times of that found for the inhalable fraction (beta 0.005 and 0.001 respectively). Mineral dust-and not only traffic-related air pollutant exposure-could be regarded as a risk factor in the process of cell aging. Our findings imply that early biological aging, as reflected in telomere shortening, may mediate the effects of occupational air pollution exposure on human health.

Advanced microscopy to elucidate cardiovascular injury and regeneration: 4D light-sheet imaging

The advent of 4-dimensional (4D) light-sheet fluorescence microscopy (LSFM) has provided an entry point for rapid image acquisition to uncover real-time cardiovascular structure and function with high axial resolution and minimal photo-bleaching/-toxicity. We hereby review the fundamental principles of our LSFM system to investigate cardiovascular morphogenesis and regeneration after injury. LSFM enables us to reveal the micro-circulation of blood cells in the zebrafish embryo and assess cardiac ventricular remodeling in response to chemotherapy-induced injury using an automated segmentation approach. Next, we review two distinct mechanisms underlying zebrafish vascular regeneration following tail amputation. We elucidate the role of endothelial Notch signaling to restore vascular regeneration after exposure to the redox active ultrafine particles (UFP) in air pollutants. By manipulating the blood viscosity and subsequently, endothelial wall shear stress, we demonstrate the mechanism whereby hemodynamic shear forces impart both mechanical and metabolic effects to modulate vascular regeneration. Overall, the implementation of 4D LSFM allows for the elucidation of mechanisms governing cardiovascular injury and regeneration with high spatiotemporal resolution.

Ultrafine Particle Exposure Reveals the Importance of FOXO1/Notch Activation Complex for Vascular Regeneration

AIMS

Redox active ultrafine particles (UFP, d < 0.2 μm) promote vascular oxidative stress and atherosclerosis. Notch signaling is intimately involved in vascular homeostasis, in which forkhead box O1 (FOXO1) acts as a co-activator of the Notch activation complex. We elucidated the importance of FOXO1/Notch transcriptional activation complex to restore vascular regeneration after UFP exposure.

RESULTS

In a zebrafish model of tail injury and repair, transgenic Tg(fli1:GFP) embryos developed vascular regeneration at 3 days post amputation (dpa), whereas UFP exposure impaired regeneration (p < 0.05, n = 20 for control, n = 28 for UFP). UFP dose dependently reduced Notch reporter activity and Notch signaling-related genes (Dll4, JAG1, JAG2, Notch1b, Hey2, Hes1; p < 0.05, n = 3). In the transgenic Tg(tp1:GFP; flk1:mCherry) embryos, UFP attenuated endothelial Notch activity at the amputation site (p < 0.05 vs. wild type [WT], n = 20). A disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) inhibitor or dominant negative (DN)-Notch1b messenger RNA (mRNA) disrupted the vascular network, whereas notch intracellular cytoplasmic domain (NICD) mRNA restored the vascular network (p < 0.05 vs. WT, n = 20). UFP reduced FOXO1 expression, but not Master-mind like 1 (MAML1) or NICD (p < 0.05, n = 3). Immunoprecipitation and immunofluorescence demonstrated that UFP attenuated FOXO1-mediated NICD pull-down and FOXO1/NICD co-localization, respectively (p < 0.05, n = 3). Although FOXO1 morpholino oligonucleotides (MOs) attenuated Notch activity, FOXO1 mRNA reversed UFP-mediated reduction in Notch activity to restore vascular regeneration and blood flow (p < 0.05 vs. WT, n = 5). Innovation and Conclusion: Our findings indicate the importance of the FOXO1/Notch activation complex to restore vascular regeneration after exposure to the redox active UFP. Antioxid. Redox Signal. 28, 1209-1223.

Indoor PM2.5 in an urban zone with heavy wood smoke pollution: The case of Temuco, Chile

Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; however, little is known about the indoor air quality in this region. A field measurement campaign at 63 households in the Temuco urban area was conducted in winter 2014 and is reported here. In this study, indoor and outdoor (24-hr) PM_2.5 and its elemental composition were measured and compared. Infiltration parameters and outdoor/indoor contributions to indoor PM_2.5 were also determined. A statistical evaluation of how various air quality interventions and household features influence indoor PM_2.5 was also performed. This study determined median indoor and outdoor PM_2.5 concentrations of 44.4 and 41.8 μg/m³, respectively. An average infiltration factor (0.62 ± 0.06) was estimated using sulfur as a tracer species. Using a simple mass balance approach, median indoor and outdoor contributions to indoor PM_2.5 concentrations were then estimated as 12.5 and 26.5 μg/m³, respectively; therefore, 68% of indoor PM_2.5 comes from outdoor infiltration. This high percentage is due to high outdoor pollution and relatively high household air exchange rates (median: 1.06 h^-1). This study found that S, Br and Rb were dominated by outdoor contributions, while Si, Ca, Ti, Fe and As originated from indoor sources. Using continuous indoor and outdoor PM_2.5 measurements, a median indoor source strength of 75 μg PM_2.5/min was estimated for the diurnal period, similar to literature results. For the evening period, the median estimate rose to 135 μg PM_2.5/min, reflecting a more intense wood burning associated to cooking and space heating at night. Statistical test results (at the 90% confidence level) support the ongoing woodstove replacement program (reducing emissions) and household weatherization subsidies (reducing heating demand) for improving indoor air quality in southern Chile, and suggest that a cookstove improvement program might be helpful as well.

Prenatal particulate matter exposure and mitochondrial dysfunction at the maternal-fetal interface: Effect modification by maternal lifetime trauma and child sex

BACKGROUND

Prenatal ambient fine particulate matter (PM_2.5) and maternal chronic psychosocial stress have independently been linked to changes in mithochondrial DNA copy number (mtDNAcn), a marker of mitochondrial response and dysfunction. Further, overlapping research shows sex-specific effects of PM_2.5 and stress on developmental outcomes. Interactions among PM_2.5, maternal stress, and child sex have not been examined in this context.

METHODS

We examined associations among exposure to prenatal PM_2.5, maternal lifetime traumatic stressors, and mtDNAcn at birth in a sociodemographically diverse pregnancy cohort (N=167). Mothers' daily exposure to PM_2.5 over gestation was estimated using a satellite-based spatio-temporally resolved prediction model. Lifetime exposure to traumatic stressors was ascertained using the Life Stressor Checklist-Revised; exposure was categorized as high vs. low based on a median split. Quantitative real-time polymerase chain reaction (qPCR) was used to determine mtDNAcn in placenta and cord blood leukocytes. Bayesian Distributed Lag Interaction regression models (BDLIMs) were used to statistically model and visualize the PM_2.5 timing-dependent pattern of associations with mtDNAcn and explore effect modification by maternal lifetime trauma and child sex.

RESULTS

Increased PM_2.5 exposure across pregnancy was associated with decreased mtDNAcn in cord blood (cumulative effect estimate=-0.78; 95%CI -1.41, -0.16). Higher maternal lifetime trauma was associated with reduced mtDNAcn in placenta (β=-0.33; 95%CI -0.63, -0.02). Among women reporting low trauma, increased PM_2.5 exposure late in pregnancy (30-38weeks gestation) was significantly associated with decreased mtDNAcn in placenta; no significant association was found in the high trauma group. BDLIMs identified a significant 3-way interaction between PM_2.5, maternal trauma, and child sex. Specifically, PM_2.5 exposure between 25 and 40weeks gestation was significantly associated with increased placental mtDNAcn among boys of mothers reporting high trauma. In contrast, PM_2.5 exposure in this same window was significantly associated with decreased placental mtDNAcn among girls of mothers reporting low trauma. Similar 3-way interactive effects were observed in cord blood.

CONCLUSIONS

These results indicate that joint exposure to PM_2.5 in late pregnancy and maternal lifetime trauma influence mtDNAcn at the maternal-fetal interface in a sex-specific manner. Additional studies will assist in understanding if the sex-specific patterns reflect distinct pathophysiological processes in addition to mitochondrial dysfunction.

Long-term high air pollution exposure induced metabolic adaptations in traffic policemen

OBJECTIVE

To assess the adverse physiological changes induced by long-term exposure to PM2.5.

METHODS

Totally 183 traffic policemen and 88 office policemen as the control group, were enrolled in this study. The concentrations of PM2.5 in both the working places of traffic and office policemen were obtained. Detailed personal questionnaires and conventional laboratory tests including hematology, fasting blood glucose, blood lipids, liver, kidney, immunity and tumor-related markers were conducted on all participants of this study.

RESULTS

A dose-response relationship between the FBG, HDL-c and CEA values and the PM2.5 exposure duration was observed. Multivariate analysis confirmed that one hour on duty outdoor per day for one year was associated with an increase in FBG of 0.005% (95% CI: 0.0004% to 0.009%), CEA of 0.012% (95% CI: 0.006% to 0.017%), and a decrease in HDL-C of 0.001% (95% CI: 0.00034% to 0.002%).

CONCLUSION

Long-term high air pollution exposure may lead to metabolism adaptation and it is likely involved in the development of cardiovascular disease and diabetes mellitus.

Are metals and pyrene levels additional factors playing a pivotal role in air pollution-induced inflammation in taxi drivers?

This study aimed to evaluate which xenobiotic (As, Hg, Pb or pyrenes) is primarily responsible for the inflammatory process in taxi drivers. Multiple regression analysis showed that Hg is the main xenobiotic responsible for the increase of cytokine levels. These associations suggest that co-exposure to pollutants could be a risk factor for health effects.

Melatonin, a Full Service Anti-Cancer Agent: Inhibition of Initiation, Progression and Metastasis

There is highly credible evidence that melatonin mitigates cancer at the initiation, progression and metastasis phases. In many cases, the molecular mechanisms underpinning these inhibitory actions have been proposed. What is rather perplexing, however, is the large number of processes by which melatonin reportedly restrains cancer development and growth. These diverse actions suggest that what is being observed are merely epiphenomena of an underlying more fundamental action of melatonin that remains to be disclosed. Some of the arresting actions of melatonin on cancer are clearly membrane receptor-mediated while others are membrane receptor-independent and involve direct intracellular actions of this ubiquitously-distributed molecule. While the emphasis of melatonin/cancer research has been on the role of the indoleamine in restraining breast cancer, this is changing quickly with many cancer types having been shown to be susceptible to inhibition by melatonin. There are several facets of this research which could have immediate applications at the clinical level. Many studies have shown that melatonin's co-administration improves the sensitivity of cancers to inhibition by conventional drugs. Even more important are the findings that melatonin renders cancers previously totally resistant to treatment sensitive to these same therapies. Melatonin also inhibits molecular processes associated with metastasis by limiting the entrance of cancer cells into the vascular system and preventing them from establishing secondary growths at distant sites. This is of particular importance since cancer metastasis often significantly contributes to death of the patient. Another area that deserves additional consideration is related to the capacity of melatonin in reducing the toxic consequences of anti-cancer drugs while increasing their efficacy. Although this information has been available for more than a decade, it has not been adequately exploited at the clinical level. Even if the only beneficial actions of melatonin in cancer patients are its ability to attenuate acute and long-term drug toxicity, melatonin should be used to improve the physical wellbeing of the patients. The experimental findings, however, suggest that the advantages of using melatonin as a co-treatment with conventional cancer therapies would far exceed improvements in the wellbeing of the patients.

Demographic and Environmental Factors Associated with Mental Health: A Cross-Sectional Study

Relevant demographic and environmental conditions need to be understood before tailoring policies to improve mental health. Using community health survey data from 25 communities in Seoul, 2013, cross-sectional associations between mental health and community level environments were assessed. Mental health outcomes (self-rated stress levels (SRS) and depressive symptoms (DS)) were analyzed. Community environmental factors included green space, green facilities, and annual PM₁₀ level (AnnPM₁₀); socio-demographic factors included sex, age, education, labor market participation, comorbidity, sleep hours, physical activity, smoking, and drinking. A total of 23,139 people with the following characteristics participated: men (44.2%); age groups 19−39 (36.0%), 40−59 (39.4%), 60−74 (19.2%), and 75+ (5.4%). Women had higher odds ratios (OR) for SRS [OR 1.22, 95% Confidence interval (CI) 1.17–1.27] and DS [OR 1.55, 95% CI 1.42–1.71]. Regular physical activity predicted SRS [OR 0.90, 95% CI 0.84–0.95] and DS [OR 0.98, 95% CI 0.88–1.10]; current smoking and drinking were adversely associated with both SRS and DS. Higher accessibility to green space (Q4) was inversely associated with DS [OR 0.89, 95% CI 0.81−0.97] compared to lower accessibility (Q1). AnnPM₁₀, annual levels for particles of aerodynamic diameter <10 µm (PM₁₀), among communities was associated with poorer SRS [OR 1.02, 95% CI 1.00–1.04] by 10 μg/m³ increases. Therefore, both demographic and environmental factors should be considered to understand mental health conditions among the general population.

Air Pollution and Mortality in China

Ambient air pollution has been an important environmental issue in most areas of China. This chapter summarized the mortality effects of short-term and long-term exposures to various air pollutants among Chinese population. The literature review identified sufficient information to support significant short-term mortality effects of various air pollutants from time series analyses and case-crossover studies, such as PM₁₀, PM_2.5, SO₂, NO₂, and O₃. On the other hand, though the literature review suggested a positive effect of long-term exposure to air pollution on mortality and lung cancer risk, the evidence has been limited among Chinese population, indicating that more studies, especially cohort studies, are warranted.