Effects of ambient air particles on the endothelin system in human pulmonary epithelial cells (A549)

The exposome in practice: an exploratory panel study of biomarkers of air pollutant exposure in Chinese people aged 60-69 years (China BAPE Study)

The exposome overhauls conventional environmental health impact research paradigms and provides a novel methodological framework that comprehensively addresses the complex, highly dynamic interplays of exogenous exposures, endogenous exposures, and modifiable factors in humans. Holistic assessments of the adverse health effects and systematic elucidation of the mechanisms underlying environmental exposures are major scientific challenges with widespread societal implications. However, to date, few studies have comprehensively and simultaneously measured airborne pollutant exposures and explored the associated biomarkers in susceptible healthy elderly subjects, potentially resulting in the suboptimal assessment and management of health risks. To demonstrate the exposome paradigm, we describe the rationale and design of a comprehensive biomarker and biomonitoring panel study to systematically explore the association between individual airborne exposure and adverse health outcomes. We used a combination of personal monitoring for airborne pollutants, extensive human biomonitoring, advanced omics analysis, confounding information, and statistical methods. We established an exploratory panel study of Biomarkers of Air Pollutant Exposure in Chinese people aged 60-69 years (China BAPE), which included 76 healthy residents from a representative community in Jinan City, Shandong Province. During the period between September 2018 and January 2019, we conducted prospective longitudinal monitoring with a 3-day assessment every month. This project: (1) leveraged advanced tools for personal airborne exposure monitoring (external exposures); (2) comprehensively characterized biological samples for exogenous and endogenous compounds (e.g., targeted and untargeted monitoring) and multi-omics scale measurements to explore potential biomarkers and putative toxicity pathways; and (3) systematically evaluated the relationships between personal exposure to air pollutants, and novel biomarkers of exposures and effects using exposome-wide association study approaches. These findings will contribute to our understanding of the mechanisms underlying the adverse health impacts of air pollution exposures and identify potential adverse clinical outcomes that can facilitate the development of effective prevention and targeted intervention techniques.

Transport of environmental natural organic matter coated silver nanoparticle across cell membrane based on membrane etching treatment and inhibitors

Environmental natural organic matters (NOMs) have great effects on the physicochemical properties of engineering nanoparticles, which may impact the transport of nanoparticles across plasma membrane and the cytotoxicity. Therefore, the kinetics, uptake pathway and mass of transporting into A549 cell membrane of silver nanoparticles (AgNPs) coated with citric acid (CA), tartaric acid (TA) and fulvic acid (FA) were investigated, respectively. CA, FA and TA enhanced the colloidal stability of AgNPs in culture medium and have greatly changed the surface plasmon resonance spectrum of AgNPs due to the absorption of CA, FA and TA on surface of AgNPs. Internalizing model showed that velocity of CA-, TA- and FA-nAg transporting into A549 cell were 5.82-, 1.69- and 0.29-fold higher than those of the control group, respectively. Intracellular mass of Ag was dependent on mass of AgNPs delivered to cell from suspension, which obeyed Logistic model and was affected by NOMs that CA- and TA-nAg showed a large promotion on intracellular mass of Ag. The lipid raft/caveolae-mediated endocytosis (LME) of A549 cell uptake of AgNPs were susceptible to CA, TA and FA that uptake of CA-, TA- and FA-nAg showed lower degree of dependent on LME than that of the control (uncoated AgNPs). Actin-involved uptake pathway and macropinocytosis would have less contribution to uptake of FA-nAg. Overall, transmembrane transport of NOMs-coated AgNPs differs greatly from that of the pristine AgNPs.

Ginkgolide B protects human pulmonary alveolar epithelial A549 cells from lipopolysaccharide-induced inflammatory responses by reducing TRIM37-mediated NF-κB activation

The treatment options for acute stroke combined with pulmonary infection are limited. Clinically, there are several therapies to promote blood circulation and dissipate blood stasis; these treatment options include ginkgolide B (GB), which has PAF (platelet activating factor)-inhibiting effects. PAF-receptor (PAF-R) antagonists are used to treat a variety of inflammatory diseases; however, the potential of PAF-R antagonists as a treatment for lung infections remains unclear. The aim of the present study is to investigate the protective effect of GB on lipopolysaccharide-induced inflammatory responses in A549 human pulmonary alveolar epithelial cells (HPAEpiC) in vitro. Cell viability and apoptosis were measured by CCK-8 and flow cytometry. TRIM37, Caspase-3, and NF-κBp65 expression levels were measured by real-time PCR and Western blotting. The release of tumor necrosis factor-α and interleukin-1β was measured by ELISA. The data indicates that GB may reduce TRIM37 expression by antagonizing the PAF-R pathway, thereby inhibiting the activation of nuclear factor-κB and alleviating the inflammatory response of alveolar epithelial cells. This study is the first to provide insight into the therapeutic potential of GB and suggests that clinical application of GB in acute stroke combined with pulmonary inflammation may be efficacious.

A National Multicity Analysis of the Causal Effect of Local Pollution, [Formula: see text], and [Formula: see text] on Mortality

BACKGROUND

Studies have long associated [Formula: see text] with daily mortality, but few applied causal-modeling methods, or at low exposures. Short-term exposure to [Formula: see text], a marker of local traffic, has also been associated with mortality but is less studied. We previously found a causal effect between local air pollution and mortality in Boston.

OBJECTIVES

We aimed to estimate the causal effects of local pollution, [Formula: see text], and [Formula: see text] on mortality in 135 U.S. cities.

METHODS

We used three methods which, under different assumptions, provide causal marginal estimates of effect: a marginal structural model, an instrumental variable analysis, and a negative exposure control. The instrumental approach used planetary boundary layer, wind speed, and air pressure as instruments for concentrations of local pollutants; the marginal structural model separated the effects of [Formula: see text] from the effects of [Formula: see text], and the negative exposure control provided protection against unmeasured confounders.

RESULTS

In 7.3 million deaths, the instrumental approach estimated that mortality increased 1.5% [95% confidence interval (CI): 1.1%, 2.0%] per [Formula: see text] increase in local pollution indexed as [Formula: see text]. The negative control exposure was not associated with mortality. Restricting our analysis to days with [Formula: see text] below [Formula: see text], we found a 1.70% (95% CI 1.11%, 2.29%) increase. With marginal structural models, we found positive significant increases in deaths with both [Formula: see text] and [Formula: see text]. On days with [Formula: see text] below [Formula: see text], we found a 0.83% (95% CI 0.39%, 1.27%) increase. Including negative exposure controls changed estimates minimally.

CONCLUSIONS

Causal-modeling techniques, each subject to different assumptions, demonstrated causal effects of locally generated pollutants on daily deaths with effects at concentrations below the current EPA daily [Formula: see text] standard. https://doi.org/10.1289/EHP2732.

In vitro toxicoproteomic analysis of A549 human lung epithelial cells exposed to urban air particulate matter and its water-soluble and insoluble fractions

Background

Toxicity of airborne particulate matter (PM) is difficult to assess because PM composition is complex and variable due to source contribution and atmospheric transformation. In this study, we used an in vitro toxicoproteomic approach to identify the toxicity mechanisms associated with different subfractions of Ottawa urban dust (EHC-93).

Methods

A549 human lung epithelial cells were exposed to 0, 60, 140 and 200 μg/cm² doses of EHC-93 (total), its insoluble and soluble fractions for 24 h. Multiple cytotoxicity assays and proteomic analyses were used to assess particle toxicity in the exposed cells.

Results

The cytotoxicity data based on cellular ATP, BrdU incorporation and LDH leakage indicated that the insoluble, but not the soluble, fraction is responsible for the toxicity of EHC-93 in A549 cells. Two-dimensional gel electrophoresis results revealed that the expressions of 206 protein spots were significantly altered after particle exposures, where 154 were identified by MALDI-TOF-TOF-MS/MS. The results from cytotoxicity assays and proteomic analyses converged to a similar finding that the effects of the total and insoluble fraction may be alike, but their effects were distinguishable, and their effects were significantly different from the soluble fraction. Furthermore, the toxic potency of EHC-93 total is not equal to the sum of its insoluble and soluble fractions, implying inter-component interactions between insoluble and soluble materials resulting in synergistic or antagonistic cytotoxic effects. Pathway analysis based on the low toxicity dose (60 μg/cm²) indicated that the two subfractions can alter the expression of those proteins involved in pathways including cell death, cell proliferation and inflammatory response in a distinguishable manner. For example, the insoluble and soluble fractions differentially affected the secretion of pro-inflammatory cytokines such as MCP-1 and IL-8 and distinctly altered the expression of those proteins (e.g., TREM1, PDIA3 and ENO1) involved in an inflammatory response pathway in A549 cells.

Conclusions

This study demonstrated the impact of different fractions of urban air particles constituted of various chemical species on different mechanistic pathways and thus on cytotoxicity effects. In vitro toxicoproteomics can be a valuable tool in mapping these differences in air pollutant exposure-related toxicity mechanisms.

Electronic supplementary material

The online version of this article (10.1186/s12989-017-0220-6) contains supplementary material, which is available to authorized users.

Particulate matter-mediated release of long pentraxin 3 (PTX3) and vascular endothelial growth factor (VEGF) in vitro: Limited importance of endotoxin and organic content

Exposure to particulate matter (PM) is associated with adverse health effects, but it is still relatively unknown which role PM sources and physicochemical properties play in the observed effects. It was postulated that PM in vitro induces release of long pentraxin 3 (PTX3) and vascular endothelial growth factor (VEGF) and that endotoxin and organic compounds present in the PM regulate this release. A contact coculture of THP-1 human leukemia monocytes and A549 human adenocarcinoma alveolar pneumocytes was exposed to PM from Traffic, Wood, Diesel, and Quartz (10-40 µg/cm²) for 12-64 h to determine release of PTX3 and VEGF. The role of endotoxin and the organic fraction in the mediator release was assessed using polymyxin B sulfate and organic extracts, respectively. Finally, antagonists were used to investigate whether the early proinflammatory cytokines interleukin (IL)-1 and tumor necrosis factor (TNF)-α affected the PTX3 and VEGF release. All PM samples induced a time-dependent release of both PTX3 and VEGF. Traffic mediated the greatest release of PTX3, whereas Wood and Diesel were more potent inducers of VEGF. The endotoxin content did not markedly affect release of either mediator, while the organic fraction exerted no significant effect on VEGF release and limited influence on PTX3 release. In addition, the IL-1 and TNF-α agonists affected PTX3 release more strongly than VEGF release. In conclusion, the current data show a limited impact of endotoxin and organic compounds on PTX3 and VEGF release. Further, the observed differences in response patterns may point toward differential regulation of PM-mediated release of PTX3 and VEGF.

Salvianolic Acid A, as a Novel ETA Receptor Antagonist, Shows Inhibitory Effects on Tumor in Vitro

Endothelin-1 (ET-1) autocrine and paracrine signaling modulate cell proliferation of tumor cells by activating its receptors, endothelin A receptor (ET_AR) and endothelin B receptor (ET_BR). Dysregulation of ET_AR activation promotes tumor development and progression. The potential of ET_AR antagonists and the dual-ET_AR and ET_BR antagonists as therapeutic approaches are under preclinical and clinical studies. Salvianolic acid A (Sal A) is a hydrophilic polyphenolic derivative isolated from Salvia miltiorrhiza Bunge (Danshen), which has been reported as an anti-cancer and cardio-protective herbal medicine. In this study, we demonstrate that Sal A inhibits ET_AR activation induced by ET-1 in both recombinant and endogenous ET_AR expression cell lines. The IC₅₀ values were determined as 5.7 µM in the HEK293/ET_AR cell line and 3.14 µM in HeLa cells, respectively. Furthermore, our results showed that Sal A suppressed cell proliferation and extended the doubling times of multiple cancer cells, including HeLa, DU145, H1975, and A549 cell lines. In addition, Sal A inhibited proliferation of DU145 cell lines stimulated by exogenous ET-1 treatment. Moreover, the cytotoxicity and cardio-toxicity of Sal A were assessed in human umbilical vein endothelial cells (HUVEC) and Human-induced pluripotent stem cell-derived cardiomyocytes (hiPS-CMs), which proved that Sal A demonstrates no cytotoxicity or cardiotoxicity. Collectively, our findings indicate that Sal A is a novel anti-cancer candidate through targeting ET_AR.

ET-1 mediates the release of reactive oxygen species and TNF-α in lung tissue by protein kinase C α and β1

BACKGROUND

The aim of this study was to determine the involvement of protein kinase C (PKC) in the ET-1 induced generation of reactive oxygen species and TNF-α in rat lungs.

METHODS

Experiments were performed on 6 groups of rats: Group I: saline-treated control; Group II: saline followed by endothelin-1 (ET-1) (3μg/kg); Group III: saline followed by selective PKC αβ1 inhibitor (Gö6976) (2μg/kg); Group IV: Gö6976 (2μg/kg) administered 30min before ET-1 (3μg/kg); Group V: saline followed by the PKC activator phorbol 12-myristate 13-acetate (PMA) (50μg/kg); Group VI: Gö6976 (2μg/kg) administered 30min before PMA (50μg/kg). After 5h, the animals were euthanized and their lungs were isolated for measurements.

RESULTS

ET-1 resulted in increase in thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) levels and lung edema, as well as a decrease in GSH/GSSG ratio compared to the controls. The level of TNF-α also was elevated in the presence of ET-1. Administration of Gö6976 30min before ET-1 injection significantly decreased lung edema, as well as the concentrations of TBARS, H2O2 and TNF-α, but increased the GSH/GSSG redox ratio compared to ET-1. Conversely, PMA elevated lung edema and TBARS, H2O2 and TNF-α concentrations, but decreased the GSH/GSSG redox ratio compared to the control group. Treatment with Gö6976 significantly ameliorated the PMA-induced oxidative stress parameters, decreased tissue TNF-α level, and lung edema.

CONCLUSION

Endothelin-1 induces ROS generation, increases TNF-α level and lung edema via activation of PKC αβ1.

Targeting antitumor effect of rhTNF-α fusion protein mediated by matrix metalloproteinase-2

The aim of this study was to examine the tumor therapy, targeting effects and side effects of tumor-targeting rhTNF-α fusion protein mediated by matrix metalloproteinase-2 in an animal model in order to provide experimental data for future development of drugs. The median lethal dose (LD50) was obtained from acute toxicity experiments. The A549 lung cancer xenograft model was established, and then randomly divided into the saline, standard substance, and low-, middle- and high-dose fusion protein experiment groups. Each group was administered drugs for 18 days. The length and width of the xenografts were measured every three days, after which the xenograft growth curve was drawn. The mice were sacrificed in each group following treatment and the tumor volume and weight were measured. The targeting, effectiveness and toxicity of the transformed fusion protein, and pathological changes of tumor and organ tissues were examined by hematoxylin and eosin (H&E) staining. Additionally, biochemical markers were used to detect damage of various organs after protein processing. Cell apoptosis and angiogenesis were determined using terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) testing and immunohistochemistry, respectively, in different dose groups. Tumor growth was markedly retarded in the high-dose experimental and standard hTNF-α groups with antitumor rates of 85.91 and 72.25%, respectively, as compared with the control group. Furthermore, the tumor tissue showed obvious apoptosis (the apoptotic index was 78.78 and 66.65%, respectively) and pathological changes in the high-dose experimental and standard hTNF-α groups. Tumor angiogenesis in each fusion protein group was inhibited (P<0.01) and the biochemical markers of various organs were greatly reduced in the high-dose experimental group (P<0.05). This finding indicated that slight toxic effects of fusion proteins were evident for the heart, liver and kidney. The reforming fusion protein can therefore target tumor tissues and efficiently kill tumor cells, with few side effects.

Ultrafine carbon particle mediated cardiovascular impairment of aged spontaneously hypertensive rats

Background

Studies provide compelling evidences for particulate matter (PM) associated cardiovascular health effects. Elderly individuals, particularly those with preexisting conditions like hypertension are regarded to be vulnerable. Experimental data are warranted to reveal the molecular pathomechanism of PM related cardiovascular impairments among aged/predisposed individuals. Thus we investigated the cardiovascular effects of ultrafine carbon particles (UfCP) on aged (12–13 months) spontaneously hypertensive rats (SHRs) and compared the findings with our pervious study on adult SHRs (6–7 months) to identify age related predisposition events in cardiovascular compromised elderly individuals.

Methods

Aged SHRs were inhalation exposed to UfCP for 24 h (~180 μg/m³) followed by radio-telemetric assessment for blood pressure (BP) and heart rate (HR). Bronchoalveolar lavage (BAL) fluid cell differentials, interleukin 6 (IL-6) and other proinflammatory cytokines; serum C-reactive protein (CRP) and haptoglobin (HPT); and plasma fibrinogen were measured. Transcript levels of hemeoxygenase 1 (HO-1), endothelin 1 (ET1), endothelin receptors A, B (ETA, ETB), tissue factor (TF), and plasminogen activator inhibitor-1 (PAI-1) were measured in the lung and heart to assess oxidative stress, endothelial dysfunction and coagulation cascade.

Result

UfCP exposed aged SHRs exhibited increased BP (4.4%) and HR (6.3%) on 1^st recovery day paralleled by a 58% increase of neutrophils and 25% increase of IL-6 in the BAL fluid. Simultaneously higher CRP, HPT and fibrinogen levels in exposed SHRs indicate systemic inflammation. HO-1, ET1, ET-A, ET-B, TF and PAI-1 were induced by 1.5-2.0 folds in lungs of aged SHRs on 1^st recovery day. However, in UfCP exposed adult SHRs these markers were up-regulated (2.5-6 fold) on 3^rd recovery day in lung without detectable pulmonary/systemic inflammation.

Conclusions

The UfCP induced pulmonary and systemic inflammation in aged SHRs is associated with oxidative stress, endothelial dysfunction and disturbed coagulatory hemostasis. UfCP exposure increased BP and HR in aged SHRs rats which was associated with lung inflammation, and increased expression of inflammatory, vasoconstriction and coagulation markers as well as systemic changes in biomarkers of thrombosis in aged SHRs. Our study provides further evidence for potential molecular mechanisms explaining the increased risk of particle mediated cardiac health effects in cardiovascular compromised elderly individuals.

Milano summer particulate matter (PM10) triggers lung inflammation and extra pulmonary adverse events in mice

Recent studies have suggested a link between particulate matter (PM) exposure and increased mortality and morbidity associated with pulmonary and cardiovascular diseases; accumulating evidences point to a new role for air pollution in CNS diseases. The purpose of our study is to investigate PM10sum effects on lungs and extra pulmonary tissues. Milano PM10sum has been intratracheally instilled into BALB/c mice. Broncho Alveolar Lavage fluid, lung parenchyma, heart and brain were screened for markers of inflammation (cell counts, cytokines, ET-1, HO-1, MPO, iNOS), cytotoxicity (LDH, ALP, Hsp70, Caspase8-p18, Caspase3-p17) for a putative pro-carcinogenic marker (Cyp1B1) and for TLR4 pathway activation. Brain was also investigated for CD68, TNF-α, GFAP. In blood, cell counts were performed while plasma was screened for endothelial activation (sP-selectin, ET-1) and for inflammation markers (TNF-α, MIP-2, IL-1β, MPO). Genes up-regulation (HMOX1, Cyp1B1, IL-1β, MIP-2, MPO) and miR-21 have been investigated in lungs and blood. Inflammation in the respiratory tract of PM10sum-treated mice has been confirmed in BALf and lung parenchyma by increased PMNs percentage, increased ET-1, MPO and cytokines levels. A systemic spreading of lung inflammation in PM10sum-treated mice has been related to the increased blood total cell count and neutrophils percentage, as well as to increased blood MPO. The blood-endothelium interface activation has been confirmed by significant increases of plasma ET-1 and sP-selectin. Furthermore PM10sum induced heart endothelial activation and PAHs metabolism, proved by increased ET-1 and Cyp1B1 levels. Moreover, PM10sum causes an increase in brain HO-1 and ET-1. These results state the translocation of inflammation mediators, ultrafine particles, LPS, metals associated to PM10sum, from lungs to bloodstream, thus triggering a systemic reaction, mainly involving heart and brain. Our results provided additional insight into the toxicity of PM10sum and could facilitate shedding light on mechanisms underlying the development of urban air pollution related diseases.

Exposure to severe urban air pollution influences cognitive outcomes, brain volume and systemic inflammation in clinically healthy children

Exposure to severe air pollution produces neuroinflammation and structural brain alterations in children. We tested whether patterns of brain growth, cognitive deficits and white matter hyperintensities (WMH) are associated with exposures to severe air pollution. Baseline and 1 year follow-up measurements of global and regional brain MRI volumes, cognitive abilities (Wechsler Intelligence Scale for Children-Revised, WISC-R), and serum inflammatory mediators were collected in 20 Mexico City (MC) children (10 with white matter hyperintensities, WMH(+), and 10 without, WMH(-)) and 10 matched controls (CTL) from a low polluted city. There were significant differences in white matter volumes between CTL and MC children - both WMH(+) and WMH(-) - in right parietal and bilateral temporal areas. Both WMH(-) and WMH(+) MC children showed progressive deficits, compared to CTL children, on the WISC-R Vocabulary and Digit Span subtests. The cognitive deficits in highly exposed children match the localization of the volumetric differences detected over the 1 year follow-up, since the deficits observed are consistent with impairment of parietal and temporal lobe functions. Regardless of the presence of prefrontal WMH, Mexico City children performed more poorly across a variety of cognitive tests, compared to CTL children, thus WMH(+) is likely only partially identifying underlying white matter pathology. Together these findings reveal that exposure to air pollution may perturb the trajectory of cerebral development and result in cognitive deficits during childhood.

The innate and adaptive immune response induced by alveolar macrophages exposed to ambient particulate matter

Emerging epidemiological evidence suggests that exposure to particulate matter (PM) air pollution increases the risk of cardiovascular events but the exact mechanism by which PM has adverse effects is still unclear. Alveolar macrophages (AM) play a major role in clearing and processing inhaled PM. This comprehensive review of research findings on immunological interactions between AM and PM provides potential pathophysiological pathways that interconnect PM exposure with adverse cardiovascular effects. Coarse particles (10 μm or less, PM(10)) induce innate immune responses via endotoxin-toll-like receptor (TLR) 4 pathway while fine (2.5 μm or less, PM(2.5)) and ultrafine particles (0.1 μm or less, UFP) induce via reactive oxygen species generation by transition metals and/or polyaromatic hydrocarbons. The innate immune responses are characterized by activation of transcription factors [nuclear factor (NF)-κB and activator protein-1] and the downstream proinflammatory cytokine [interleukin (IL)-1β, IL-6, and tumor necrosis factor-α] production. In addition to the conventional opsonin-dependent phagocytosis by AM, PM can also be endocytosed by an opsonin-independent pathway via scavenger receptors. Activation of scavenger receptors negatively regulates the TLR4-NF-κB pathway. Internalized particles are subsequently subjected to adaptive immunity involving major histocompatibility complex class II (MHC II) expression, recruitment of costimulatory molecules, and the modulation of the T helper (Th) responses. AM show atypical antigen presenting cell maturation in which phagocytic activity decreases while both MHC II and costimulatory molecules remain unaltered. PM drives AM towards a Th1 profile but secondary responses in a Th1- or Th-2 up-regulated milieu drive the response in favor of a Th2 profile.

Diesel exhaust inhalation induces heat shock protein 70 expression in vivo

Exposure to urban air pollution is an independent risk factor for increased cardiovascular diseases. Heat shock protein 70 (HSP70) has been implicated in the pathogenesis of vascular dysfunction and cardiovascular diseases. This study has been designed to determine whether inhalation of urban air induces HSP70 expression in the lung and blood as well as the association of HSP70 and air pollution-induced vascular dysfunction. Apolipoprotein E (Apo-E) deficient mice were exposed to diesel exhaust (DE) either acutely (3 days, 200 or 400 µg/m(3) for 6 h/day) or chronically (7 weeks, 200 or 400 µg/m(3) for 6 h/day). HSP70 was measured in the lung using immunohistochemistry, and in the plasma by ELISA. Abdominal aorta rings were used to determine vascular functional responses. Chronic DE-exposure increased the fraction of HSP70 positive alveolar macrophages (AM) that was related to the fraction of particle-laden AM in the lung (r(2) =  0.48, p <0.01). Chronic DE-exposure increased plasma HSP70 levels and reduced blood vessel responses to phenylephrine (PE). The fraction of particle-laden HSP70 positive AM was associated with abnormal vasoconstriction responses to PE induced by DE-exposure (r(2) = 0.12, p = 0.02). Our results show that chronic inhalation of DE increases HSP70 expression in the lung and systemic circulation, and we postulate that HSP70 possibly contributes to air pollution induced vascular dysfunction and cardiovascular diseases.

The relationship of air pollution and surrogate markers of endothelial dysfunction in a population-based sample of children

Background

This study aimed to assess the relationship of air pollution and plasma surrogate markers of endothelial dysfunction in the pediatric age group.

Methods

This cross-sectional study was conducted in 2009-2010 among 125 participants aged 10-18 years. They were randomly selected from different areas of Isfahan city, the second large and air-polluted city in Iran. The association of air pollutants' levels with serum thrombomodulin (TM) and tissue factor (TF) was determined after adjustment for age, gender, anthropometric measures, dietary and physical activity habits.

Results

Data of 118 participants was complete and was analyzed. The mean age was 12.79 (2.35) years. The mean pollution standards index (PSI) value was at moderate level, the mean particular matter measuring up to 10 μm (PM₁₀) was more than twice the normal level. Multiple linear regression analysis showed that TF had significant relationship with all air pollutants except than carbon monoxide, and TM had significant inverse relationship with ozone. The odds ratio of elevated TF was significantly higher in the upper vs. the lowest quartiles of PM₁₀, ozone and PSI. The corresponding figures were in opposite direction for TM.

Conclusions

The relationship of air pollutants with endothelial dysfunction and pro-coagulant state can be an important factor in the development of atherosclerosis from early life. This finding should be confirmed in future longitudinal studies. Concerns about the harmful effects of air pollution on children's health should be considered a top priority for public health policy; it should be underscored in primordial and primary prevention of chronic diseases.

The inflammatory response in lungs of rats exposed on the airborne particles collected during different seasons in four European cities

Epidemiological studies have reported associations of ambient particulate air pollution, especially particulate matter (PM) less than 10 μm with exacerbations of asthma and chronic obstructive pulmonary disease. In an in vivo model, we have tested the toxicity of urban airborne particles collected during spring, summer, and winter seasons in four cities (Amsterdam, Lodz, Oslo, and Rome) spread across Europe. The seasonal differences in inflammatory responses were striking, and almost all the study parameters were affected by PM. Coarse fractions of the urban particle samples were less potent per unit mass than the fine fractions in increasing cytokine [macrophage inflammatory protein (MIP)-2 and tumor necrosis factor (TNF)-α] levels and in reducing Clara-cell secretory protein (CC16) levels. This study shows that PM collected at 4 contrasting sites across Europe and during different seasons have differences in toxic potency. These differences were even more prominent between the fine and coarse fractions of the PM.

The time course of vasoconstriction and endothelin receptor A expression in pulmonary arterioles of mice continuously exposed to ambient urban levels of air pollution

The present study aimed to verify the time course of the effects of environmental levels of urban air pollution toxicity on lung arterioles. BALB/c mice (n=56) were continuously exposed to selective chambers equipped with (filtered, F) or without (non-filtered, NF) filter devices for particles and toxic gases for 24h/day, over 14, 21, 30 or 45 days. After exposure, we evaluated the lumen-wall relationship (an estimator of arteriolar narrowing), endothelial nitric oxide synthase (eNOS) and endothelin type A receptor (ETAr) expression in the vascular wall and inflammatory influx of the peribronchiolar area. Concentrations of fine particulate matter (PM<or=2.5 microg/m(3)), nitrogen dioxide (NO(2)), black smoke (BS), humidity and temperature in both the environment and inside the chambers were measured daily. Filters cleared 100% of BS and 97% of PM inside the F chamber. The arteriole wall of the lungs of mice from NF chamber had an increased ETAr expression (p<or=0.042) concomitant to a decrease in the lumen/wall ratio (p=0.02) on the early days of exposure, compared to controls. They also presented a progressive increment of inflammatory influx in the peribronchiolar area during the study (p=0.04) and decrement of the eNOS expression on the 45th day of exposure in both vascular layers (p<or=0.03). We found that after 14 days of exposure, the ambient levels of air pollutants in Sao Paulo induced vasoconstriction that was associated with an increase in ETAr expression. These vascular results do not appear to be coupled to the progressive inflammatory influx in lung tissue, suggesting a down-regulation of vasoconstrictive mechanisms through an imbalance in the cytokines network. It is likely that these responses are protective measures that decrease tissue damage brought about by continuous exposure to air pollutants.

Trial to evaluate effects of ambient particulate matter on health: A preliminary study using two-dimensional gel electrophoresis

OBJECTIVES

Particulate air pollution is a serious problem all over the world, and the development of a method to evaluate the health effects of ambient particles is necessary. In this study, cells cultured in vitro were exposed to particles sampled at the side of a main road, and their protein expression levels were examined.

METHODS

Ambient particles were collected at the side of a main road using a high-volume air sampler. Some of the collected particles (crude particles) were treated with an organic solvent to remove chemical components, and the resulting residues were used as residual particles. Cells from the mouse alveolar epithelial cell line LA-4 were inoculated into tissue-culture dishes at 1.4×10(4)/cm(2), exposed to each type of particle or artificial carbon particles (Printex 90) that were dispersed using an ultrasonic homogenizer by mixing in the medium twice at 24 and 48 hours, and incubated for up to 72 hours after the start of inoculation. After exposure, the number of cells and intracellular dehydrogenase activity were measured. Proteins extracted from the cells were subjected to two-dimensional gel electrophoresis with isoelectric focusing at pHs 4-7 using a 10% acrylamide gel, and their expression levels were analyzed after fluorescent staining.

RESULTS

The intracellular dehydrogenase activity of the cells significantly decreased as a result of exposure to the residual (0.70-fold) and crude (0.84-fold) particles compared with that of the control, but it showed no change as a result of exposure to Printex 90. The protein expression levels in the cells exposed to the particles increased or decreased similarly, but different expression levels were also observed. There were differences in the effects observed between the cells exposed to the artificial carbon particles and those exposed to particles collected from ambient air.

CONCLUSION

This study indicates that protein expression levels in cells change in response to exposure to particles collected from ambient air. To evaluate the effects of particles on health, it is considered necessary to use particles collected from ambient air.