First-in-human controlled inhalation of thin graphene oxide nanosheets to study acute cardiorespiratory responses.

Graphene oxide nanomaterials are being developed for wide-ranging applications but are associated with potential safety concerns for human health. We conducted a double-blind randomized controlled study to determine how the inhalation of graphene oxide nanosheets affects acute pulmonary and cardiovascular function. Small and ultrasmall graphene oxide nanosheets at a concentration of 200 µg m-3 or filtered air were inhaled for 2 h by 14 young healthy volunteers in repeated visits. Overall, graphene oxide nanosheet exposure was well tolerated with no adverse effects. Heart rate, blood pressure, lung function and inflammatory markers were unaffected irrespective of graphene oxide particle size. Highly enriched blood proteomics analysis revealed very few differential plasma proteins and thrombus formation was mildly increased in an ex vivo model of arterial injury. Overall, acute inhalation of highly purified and thin nanometre-sized graphene oxide nanosheets was not associated with overt detrimental effects in healthy humans. These findings demonstrate the feasibility of carefully controlled human exposures at a clinical setting for risk assessment of graphene oxide, and lay the foundations for investigating the effects of other two-dimensional nanomaterials in humans. Clinicaltrials.gov ref: NCT03659864.

Current exposure to phthalates and DINCH in European children and adolescents - Results from the HBM4EU Aligned Studies 2014 to 2021.

Phthalates are mainly used as plasticizers for polyvinyl chloride (PVC). Exposure to several phthalates is associated with different adverse effects most prominently on the development of reproductive functions. The HBM4EU Aligned Studies (2014-2021) have investigated current European exposure to ten phthalates (DEP, BBzP, DiBP, DnBP, DCHP, DnPeP, DEHP, DiNP, DiDP, DnOP) and the substitute DINCH to answer the open policy relevant questions which were defined by HBM4EU partner countries and EU institutions as the starting point of the programme. The exposure dataset includes ∼5,600 children (6-11 years) and adolescents (12-18 years) from up to 12 countries per age group and covering the North, East, South and West European regions. Study data from participating studies were harmonised with respect to sample size and selection of participants, selection of biomarkers, and quality and comparability of analytical results to provide a comparable perspective of European exposure. Phthalate and DINCH exposure were deduced from urinary excretions of metabolites, where concentrations were expressed as their key descriptor geometric mean (GM) and 95th percentile (P95). This study aims at reporting current exposure levels and differences in these between European studies and regions, as well as comparisons to human biomonitoring guidance values (HBM-GVs). GMs for children were highest for ∑DEHP metabolites (33.6 µg/L), MiBP (26.6 µg/L), and MEP (24.4 µg/L) and lowest for∑DiDP metabolites (1.91 µg/L) and ∑DINCH metabolites (3.57 µg/L). In adolescents highest GMs were found for MEP (43.3 µg/L), ∑DEHP metabolites (28.8 µg/L), and MiBP (25.6 µg/L) and lowest for ∑DiDP metabolites (= 2.02 µg/L) and ∑DINCH metabolites (2.51 µg/L). In addition, GMs and P95 stratified by European region, sex, household education level, and degree of urbanization are presented. Differences in average biomarker concentrations between sampling sites (data collections) ranged from factor 2 to 9. Compared to the European average, children in the sampling sites OCC (Denmark), InAirQ (Hungary), and SPECIMEn (The Netherlands) had the lowest concentrations across all metabolites and ESTEBAN (France), NAC II (Italy), and CROME (Greece) the highest. For adolescents, comparably higher metabolite concentrations were found in NEB II (Norway), PCB cohort (Slovakia), and ESTEBAN (France), and lower concentrations in POLAES (Poland), FLEHS IV (Belgium), and GerES V-sub (Germany). Multivariate analyses (Survey Generalized Linear Models) indicate compound-specific differences in average metabolite concentrations between the four European regions. Comparison of individual levels with HBM-GVs revealed highest rates of exceedances for DnBP and DiBP, with up to 3 and 5%, respectively, in children and adolescents. No exceedances were observed for DEP and DINCH. With our results we provide current, detailed, and comparable data on exposure to phthalates in children and - for the first time - in adolescents, and - for the first time - on DINCH in children and adolescents of all four regions of Europe which are particularly suited to inform exposure and risk assessment and answer open policy relevant questions.

Road tunnel-derived coarse, fine and ultrafine particulate matter: physical and chemical characterization and pro-inflammatory responses in human bronchial epithelial cells.

BACKGROUND: Traffic particulate matter (PM) comprises a mixture of particles from fuel combustion and wear of road pavement, tires and brakes. In countries with low winter temperatures the relative contribution of mineral-rich PM from road abrasion may be especially high due to use of studded tires during winter season. The aim of the present study was to sample and characterize size-fractioned PM from two road tunnels paved with different stone materials in the asphalt, and to compare the pro-inflammatory potential of these fractions in human bronchial epithelial cells (HBEC3-KT) in relation to physicochemical characteristics. METHODS: The road tunnel PM was collected with a vacuum pump and a high-volume cascade impactor sampler. PM was sampled during winter, both during humid and dry road surface conditions, and before and after cleaning the tunnels. Samples were analysed for hydrodynamic size distribution, content of elemental carbon (EC), organic carbon (OC) and endotoxin, and the capacity for acellular generation of reactive oxygen species. Cytotoxicity and pro-inflammatory responses were assessed in HBEC3-KT cells after exposure to coarse (2.5-10 µm), fine (0.18-2.5 µm) and ultrafine PM (≤ 0.18 µm), as well as particles from the respective stone materials used in the pavement. RESULTS: The pro-inflammatory potency of the PM samples varied between road tunnels and size fractions, but showed more marked responses than for the stone materials used in asphalt of the respective tunnels. In particular, fine samples showed significant increases as low as 25 µg/mL (2.6 µg/cm2) and were more potent than coarse samples, while ultrafine samples showed more variable responses between tunnels, sampling conditions and endpoints. The most marked responses were observed for fine PM sampled during humid road surface conditions. Linear correlation analysis showed that particle-induced cytokine responses were correlated to OC levels, while no correlations were observed for other PM characteristics. CONCLUSIONS: The pro-inflammatory potential of fine road tunnel PM sampled during winter season was high compared to coarse PM. The differences between the PM-induced cytokine responses were not related to stone materials in the asphalt. However, the ratio of OC to total PM mass was associated with the pro-inflammatory potential.

Unveiling the Toxicity of Fine and Nano-Sized Airborne Particles Generated from Industrial Thermal Spraying Processes in Human Alveolar Epithelial Cells.

High-energy industrial processes have been associated with particle release into workplace air that can adversely affect workers' health. The present study assessed the toxicity of incidental fine (PGFP) and nanoparticles (PGNP) emitted from atmospheric plasma (APS) and high-velocity oxy-fuel (HVOF) thermal spraying. Lactate dehydrogenase (LDH) release, 2-(4-nitrophenyl)-2H-5-tetrazolio]-1,3-benzene disulfonate (WST-1) metabolisation, intracellular reactive oxygen species (ROS) levels, cell cycle changes, histone H2AX phosphorylation (γ-H2AX) and DNA damage were evaluated in human alveolar epithelial cells at 24 h after exposure. Overall, HVOF particles were the most cytotoxic to human alveolar cells, with cell viability half-maximal inhibitory concentration (IC50) values of 20.18 µg/cm2 and 1.79 µg/cm2 for PGFP and PGNP, respectively. Only the highest tested concentration of APS-PGFP caused a slight decrease in cell viability. Particle uptake, cell cycle arrest at S + G2/M and γ-H2AX augmentation were observed after exposure to all tested particles. However, higher levels of γ-H2AX were found in cells exposed to APS-derived particles (~16%), while cells exposed to HVOF particles exhibited increased levels of oxidative damage (~17% tail intensity) and ROS (~184%). Accordingly, APS and HVOF particles seem to exert their genotoxic effects by different mechanisms, highlighting that the health risks of these process-generated particles at industrial settings should not be underestimated.

In Vitro Toxicity of Industrially Relevant Engineered Nanoparticles in Human Alveolar Epithelial Cells: Air-Liquid Interface versus Submerged Cultures.

Diverse industries have already incorporated within their production processes engineered nanoparticles (ENP), increasing the potential risk of worker inhalation exposure. In vitro models have been widely used to investigate ENP toxicity. Air-liquid interface (ALI) cell cultures have been emerging as a valuable alternative to submerged cultures as they are more representative of the inhalation exposure to airborne nano-sized particles. We compared the in vitro toxicity of four ENP used as raw materials in the advanced ceramics sector in human alveolar epithelial-like cells cultured under submerged or ALI conditions. Submerged cultures were exposed to ENP liquid suspensions or to aerosolised ENP at ALI. Toxicity was assessed by determining LDH release, WST-1 metabolisation and DNA damage. Overall, cells were more sensitive to ENP cytotoxic effects when cultured and exposed under ALI. No significant cytotoxicity was observed after 24 h exposure to ENP liquid suspensions, although aerosolised ENP clearly affected cell viability and LDH release. In general, all ENP increased primary DNA damage regardless of the exposure mode, where an increase in DNA strand-breaks was only detected under submerged conditions. Our data show that at relevant occupational concentrations, the selected ENP exert mild toxicity to alveolar epithelial cells and exposure at ALI might be the most suitable choice when assessing ENP toxicity in respiratory models under realistic exposure conditions.

Comparative toxicity of ultrafine particles around a major airport in human bronchial epithelial (Calu-3) cell model at the air-liquid interface.

Relatively high concentrations of ultrafine particles (UFPs) have been observed around airports, in which aviation and road traffic emissions are the major sources. This raises concerns about the potential health impacts of airport UFPs, particularly in comparison to those emitted by road traffic. UFPs mainly derived from aviation or road traffic emissions were collected from a location near a major international airport, Amsterdam-Schiphol airport (AMS), depending on the wind direction, along with UFPs from an aircraft turbine engine at low and full thrust. Human bronchial epithelial cells (Calu-3) model in combination with an air-liquid interface (ALI) cloud system was used for the in vitro exposure to UFPs at low doses ranging from 0.09 to 2.07 µg/cm2. Particle size distribution was measured. Cell viability, cytotoxicity and inflammatory potential (interleukin (IL) 6 and 8 secretion) on Calu-3 cells were assessed after exposure for 24 h. The biological measurements on Calu-3 cells confirm that pro-inflammatory responses still can be activated at the high cell viability (> 80%) and low cytotoxicity. By the Benchmark Dose (BMD) analysis, Airport and Non-Airport (road traffic) UFPs as well as UFPs samples from a turbine engine have similar toxic properties. Our results suggest that UFPs from aviation and road traffic in airport surroundings may have similar adverse effects on public health.

Differences in cytotoxicity of lung epithelial cells exposed to titanium dioxide nanofibers and nanoparticles: Comparison of air-liquid interface and submerged cell cultures.

Air Liquid Interface (ALI) system has emerged as a useful tool for toxicity evaluation of nanomaterials related to inhalation since the system mimics the aerosol exposure. We compared the biological responses of lung epithelial cells exposed to titanium dioxide (TiO2) nanofibers and nanoparticles in ALI and submerged cell cultures systems. Cells were exposed to 2 and 10 µg/cm2 for 24 h, 48 h and 72 h and LDH release, TiO2 internalization, DNA-double strand breaks (DSBs) and ROS production were assessed. LDH release was similar in both systems and particles had higher cytoplasmic uptake in submerged systems. Both TiO2 types were located in the cytoplasm but nanofibers had nuclear uptake regardless to the system tested. Cells exposed to TiO2 nanofibers had higher DSBs in the ALI system than in submerged cell cultures but cells exposed to TiO2 nanoparticles had similar DSBs in both systems. ROS production was higher in cells exposed to TiO2 nanofibers compared to cells exposed to TiO2 nanoparticles. In conclusion, cytotoxicity of lung epithelial cells was similar in ALI or submerged cell cultures, however cells exposed to TiO2 nanofibers displayed higher toxicity than cells exposed to TiO2 nanoparticles.

Agreement of central site measurements and land use regression modeled oxidative potential of PM2.5 with personal exposure.

Oxidative potential (OP) of ambient particulate matter (PM) has been suggested as a health-relevant exposure metric. In order to use OP for exposure assessment, information is needed about how well central site OP measurements and modeled average OP at the home address reflect temporal and spatial variation of personal OP. We collected 96-hour personal, home outdoor and indoor PM2.5 samples from 15 volunteers living either at traffic, urban or regional background locations in Utrecht, the Netherlands. OP was also measured at one central reference site to account for temporal variations. OP was assessed using electron spin resonance (OP(ESR)) and dithiothreitol (OP(DTT)). Spatial variation of average OP at the home address was modeled using land use regression (LUR) models. For both OP(ESR) and OP(DTT), temporal correlations of central site measurements with home outdoor measurements were high (R>0.75), and moderate to high (R=0.49-0.70) with personal measurements. The LUR model predictions for OP correlated significantly with the home outdoor concentrations for OP(DTT) and OP(ESR) (R=0.65 and 0.62, respectively). LUR model predictions were moderately correlated with personal OP(DTT) measurements (R=0.50). Adjustment for indoor sources, such as vacuum cleaning and absence of fume-hood, improved the temporal and spatial agreement with measured personal exposure for OP(ESR). OP(DTT) was not associated with any indoor sources. Our study results support the use of central site OP for exposure assessment of epidemiological studies focusing on short-term health effects.

Spatial Variation and Land Use Regression Modeling of the Oxidative Potential of Fine Particles.

BACKGROUND: Oxidative potential (OP) has been suggested to be a more health-relevant metric than particulate matter (PM) mass. Land use regression (LUR) models can estimate long-term exposure to air pollution in epidemiological studies, but few have been developed for OP. OBJECTIVES: We aimed to characterize the spatial contrasts of two OP methods and to develop and evaluate LUR models to assess long-term exposure to the OP of PM2.5. METHODS: Three 2-week PM2.5 samples were collected at 10 regional background, 12 urban background, and 18 street sites spread over the Netherlands/Belgium in 1 year and analyzed for OP using electron spin resonance (OP(ESR)) and dithiothreitol (OP(DTT)). LUR models were developed using temporally adjusted annual averages and a range of land-use and traffic-related GIS variables. RESULTS: Street/urban background site ratio was 1.2 for OP(DTT) and 1.4 for OP(ESR), whereas regional/urban background ratio was 0.8 for both. OP(ESR) correlated moderately with OP(DTT) (R2 = 0.35). The LUR models included estimated regional background OP, local traffic, and large-scale urbanity with explained variance (R2) of 0.60 for OP(DTT) and 0.67 for OP(ESR). OP(DTT) and OP(ESR) model predictions were moderately correlated (R2 = 0.44). OP model predictions were moderately to highly correlated with predictions from a previously published PM2.5 model (R2 = 0.37-0.52), and highly correlated with predictions from previously published models of traffic components (R2 > 0.50). CONCLUSION: LUR models explained a large fraction of the spatial variation of the two OP metrics. The moderate correlations among the predictions of OP(DTT), OP(ESR), and PM2.5 models offer the potential to investigate which metric is the strongest predictor of health effects. CITATION: Yang A, Wang M, Eeftens M, Beelen R, Dons E, Leseman DL, Brunekreef B, Cassee FR, Janssen NA, Hoek G. 2015. Spatial variation and land use regression modeling of the oxidative potential of fine particles. Environ Health Perspect 123:1187-1192; http://dx.doi.org/10.1289/ehp.1408916.

Cell toxicity and oxidative potential of engine exhaust particles: impact of using particulate filter or biodiesel fuel blend.

The link between emissions of vehicular particulate matter (PM) and adverse health effects is well established. However, the influence of new emission control technologies and fuel types on both PM emissions and health effects has been less well investigated. We examined the health impact of PM emissions from two vehicles equipped with or without a diesel particulate filter (DPF). Both vehicles were powered either with diesel (B0) or a 50% v/v biodiesel blend (B50). The DPF effectively decreased PM mass emissions (∼85%), whereas the fuel B50 without DPF lead to less reduction (∼50%). The hazard of PM per unit distance driven was decreased for the DPF-equipped vehicle as indicated by a reduced cytotoxicity, oxidative, and pro-inflammatory potential. This was not evident and even led to an increase when the hazard was expressed on a per unit of mass basis. In general, the PM oxidative potential was similar or reduced for the B50 compared to the B0 powered vehicle. However, the use of B50 resulted in increased cytotoxicity and IL-6 release in BEAS-2B cells irrespective of the expression metric. This study shows that PM mass reduction achieved by the use of B50 will not necessarily decrease the hazard of engine emissions, while the application of a DPF has a beneficial effect on both PM mass emission and PM hazard.

Pulmonary and cardiovascular effects of traffic-related particulate matter: 4-week exposure of rats to roadside and diesel engine exhaust particles.

Traffic-related particulate matter (PM) may play an important role in the development of adverse health effects, as documented extensively in acute toxicity studies. However, rather little is known about the impacts of prolonged exposure to PM. We hypothesized that long-term exposure to PM from traffic adversely affects the pulmonary and cardiovascular system through exacerbation of an inflammatory response. To examine this hypothesis, Fisher F344 rats, with a mild pulmonary inflammation at the onset of exposure, were exposed for 4 weeks, 5 days/week for 6 h a day to: (a) diluted diesel engine exhaust (PM(DEE)), or: (b) near roadside PM (PM(2.5)). Ultrafine particulates, which are largely present in diesel soot, may enter the systemic circulation and directly or indirectly trigger cardiovascular effects. Hence, we assessed the effects of traffic-related PM on pulmonary inflammation and activity of procoagulants, vascular function in arteries, and cytokine levels in the heart 24 h after termination of the exposures. No major adverse health effects of prolonged exposure to traffic-related PM were detected. However, some systemic effects due to PM(DEE) exposure occurred including decreased numbers of white blood cells and reduced von Willebrand factor protein in the circulation. In addition, lung tissue factor activity is reduced in conjunction with reduced lung tissue thrombin generation. To what extent these alterations contribute to thrombotic effects and vascular diseases remains to be established. In conclusion, prolonged exposure to traffic-related PM in healthy animals may not be detrimental due to various biological adaptive response mechanisms.

Diesel engine exhaust initiates a sequence of pulmonary and cardiovascular effects in rats.

This study was designed to determine the sequence of events leading to cardiopulmonary effects following acute inhalation of diesel engine exhaust in rats. Rats were exposed for 2 h to diesel engine exhaust (1.9 mg/m(3)), and biological parameters related to antioxidant defense, inflammation, and procoagulation were examined after 4, 18, 24, 48, and 72 h. This in vivo inhalation study showed a pulmonary anti-oxidant response (an increased activity of the anti-oxidant enzymes glutathione peroxidase and superoxide dismutase and an increase in heme oxygenase-1 protein, heme oxygenase activity, and uric acid) which precedes the inflammatory response (an increase in IL-6 and TNF-α). In addition, increased plasma thrombogenicity and immediate anti-oxidant defense gene expression in aorta tissue shortly after the exposure might suggest direct translocation of diesel engine exhaust components to the vasculature but mediation by other pathways cannot be ruled out. This study therefore shows that different stages in oxidative stress are not only affected by dose increments but are also time dependent.

Particle induced toxicity in relation to transition metal and polycyclic aromatic hydrocarbon contents.

Exposure to ambient particulate matter (PM) is statistically significantly associated with morbidity and mortality. The objectives of this study were (a) to investigate in vivo pulmonary and systemic cytotoxicity and inflammatory activity in compromised animals exposed to PM and (b) to investigate the relationships of the outcomes to the chemical compositions of particular polycyclic aromatic hydrocarbons (PAH) and transition metals in the PM. The PM samples were collected in European cities representing contrasting situations. Exposure of spontaneously hypertensive rats (7 mg of PM/kg) resulted in pulmonary inflammation, cellular toxicity and the induction of blood fibrinogen. Coarse PM generally caused stronger effects per mg than fine particles. Positive correlations between lactate dehydrogenase, proteins, and some inflammation parameters and the particle metal and PAH content were found. PM rich in PAH also led to increased blood fibrinogen. Removal of particles but not the organics (i.e., PAH) of a sample led to reduced inflammation in the lungs. The present study highlights the importance of metals as well as PM-bound PAH in particle biological outcomes. It supports the hypothesis that, on an equal mass basis, particle health effects differ due to differences in compositions and size.

Beneficial cardiovascular effects of reducing exposure to particulate air pollution with a simple facemask.

BACKGROUND: Exposure to air pollution is an important risk factor for cardiovascular morbidity and mortality, and is associated with increased blood pressure, reduced heart rate variability, endothelial dysfunction and myocardial ischaemia. Our objectives were to assess the cardiovascular effects of reducing air pollution exposure by wearing a facemask. METHODS: In an open-label cross-over randomised controlled trial, 15 healthy volunteers (median age 28 years) walked on a predefined city centre route in Beijing in the presence and absence of a highly efficient facemask. Personal exposure to ambient air pollution and exercise was assessed continuously using portable real-time monitors and global positional system tracking respectively. Cardiovascular effects were assessed by continuous 12-lead electrocardiographic and ambulatory blood pressure monitoring. RESULTS: Ambient exposure (PM2.5 86 +/- 61 vs 140 +/- 113 mug/m3; particle number 2.4 +/- 0.4 vs 2.3 +/- 0.4 x 104 particles/cm3), temperature (29 +/- 1 vs 28 +/- 3 degrees C) and relative humidity (63 +/- 10 vs 64 +/- 19%) were similar (P > 0.05 for all) on both study days. During the 2-hour city walk, systolic blood pressure was lower (114 +/- 10 vs 121 +/- 11 mmHg, P < 0.01) when subjects wore a facemask, although heart rate was similar (91 +/- 11 vs 88 +/- 11/min; P > 0.05). Over the 24-hour period heart rate variability increased (SDNN 65.6 +/- 11.5 vs 61.2 +/- 11.4 ms, P < 0.05; LF-power 919 +/- 352 vs 816 +/- 340 ms2, P < 0.05) when subjects wore the facemask. CONCLUSION: Wearing a facemask appears to abrogate the adverse effects of air pollution on blood pressure and heart rate variability. This simple intervention has the potential to protect susceptible individuals and prevent cardiovascular events in cities with high concentrations of ambient air pollution.

Exposure to concentrated ambient particles does not affect vascular function in patients with coronary heart disease.

BACKGROUND: Exposure to fine particulate air pollution is associated with increased cardiovascular morbidity and mortality. We previously demonstrated that exposure to dilute diesel exhaust causes vascular dysfunction in humans. OBJECTIVES: We conducted a study to determine whether exposure to ambient particulate matter causes vascular dysfunction. METHODS: Twelve male patients with stable coronary heart disease and 12 age-matched volunteers were exposed to concentrated ambient fine and ultrafine particles (CAPs) or filtered air for 2 hr using a randomized, double-blind cross-over study design. We measured peripheral vascular vasomotor and fibrinolytic function, and inflammatory variables-including circulating leukocytes, serum C-reactive protein, and exhaled breath 8-isoprostane and nitrotyrosine-6-8 hr after both exposures. RESULTS: Particulate concentrations (mean +/- SE) in the exposure chamber (190+/-37 microg/m(3)) were higher than ambient levels (31+/-8 microg/m(3)) and levels in filtered air (0.5+/-0.4 microg/m(3); p<0.001). Chemical analysis of CAPs identified low levels of elemental carbon. Exhaled breath 8-isoprostane concentrations increased after exposure to CAPs (16.9+/-8.5 vs. 4.9+/-1.2 pg/mL, p<0.05), but markers of systemic inflammation were largely unchanged. Although there was a dose-dependent increase in blood flow and plasma tissue plasminogen activator release (p<0.001 for all), CAPs exposure had no effect on vascular function in either group. CONCLUSIONS: Despite achieving marked increases in particulate matter, exposure to CAPs--low in combustion-derived particles--did not affect vasomotor or fibrinolytic function in either middle-aged healthy volunteers or patients with coronary heart disease. These findings contrast with previous exposures to dilute diesel exhaust and highlight the importance of particle composition in determining the vascular effects of particulate matter in humans.

Lung inflammation and thrombogenic responses in a time course study of Csb mice exposed to ozone.

Ozone is a well-known oxidant air pollutant, inhalation of which can result in oxidative stress, and lead to pulmonary inflammation. The aim of this study was to evaluate the time-course events after a single ozone exposure in transcription-coupled repair defective Csb and wild type mice. Mice were exposed for 3 h to 2 ppm ozone and biological parameters related to oxidative stress and inflammation were examined in the lungs at 0, 4, 9, 24 and 48 h after exposure. In addition the procoagulant and thrombomodulin activities were explored by a combination of assays for tissue factor and thrombin generation. This study revealed a significant biological response to ozone, for both Csb and wild type mice. The onset of inflammation in Csb mice, as indicated by an increase in interleukin-6, tumor necrosis factor-alpha and total cell influx, occurred earlier compared with those seen in wild type mice. On the other hand, Csb mice showed a delayed antioxidant reaction compared with wild type mice. Both genotypes developed a procoagulant reaction characterized by a stably increased tissue factor activity and a progressive increase in thrombin generation after 2 days. These experiments have shown that ozone, a well-known toxic substance from the environment, induces not only inflammation, but also procoagulant reactions in the lungs of mice. These results have implications for understanding the systemic effects induced by oxidant air pollutants.

Toxicity of coarse and fine particulate matter from sites with contrasting traffic profiles.

Residence in urban areas with much traffic has been associated with various negative health effects. However, the contribution of traffic emissions to these adverse health effects has not been fully determined. Therefore, the objective of this in vivo study is to compare the pulmonary and systemic responses of rats exposed to particulate matter (PM) obtained from various locations with contrasting traffic profiles. Samples of coarse (2.5 microm-10 microm) and fine (0.1 microm-2.5 microm) PM were simultaneously collected at nine sites across Europe with a high-volume cascade impactor. Six PM samples from various locations were selected on the basis of contrast in in vitro analysis, chemical composition, and traffic profiles. We exposed spontaneously hypertensive (SH) rats to a single dose (3 mg PM/kg body weight or 10 mg PM/kg body weight) of either coarse or fine PM by intratracheal instillation. We assessed changes in biochemical markers, cell differentials, and histopathological changes in the lungs and blood 24 h postexposure. The dose-related adverse effects that both coarse and fine PM induced in the lungs and vascular system were mainly related to cytotoxicity, inflammation, and blood viscosity. We observed clear differences in the extent of these responses to PM from the various locations at equivalent dose levels. There was a trend that suggests that samples from high-traffic sites were the most toxic. It is likely that the toxicological responses of SH rats were associated with specific PM components derived from brake wear (copper and barium), tire wear (zinc), and wood smoke (potassium).

Ozone induces clear cellular and molecular responses in the mouse lung independently of the transcription-coupled repair status.

The oxidant ozone is a well-known air pollutant, inhalation of which is associated with respiratory tract inflammation and functional alterations of the lung. It is well established as an inducer of intracellular oxidative stress. We investigated whether Cockayne syndrome B, transcription-coupled, repair-deficient mice (Csb(-/-)), known to be sensitive to oxidative stressors, respond differently to ozone than repair-proficient controls (Csb(+/-)). Mice were exposed to 0.8 parts/million ozone for 8 h, and we examined a wide range of biological parameters in the lung at the gene expression, protein, and cellular level 4 h after the ozone exposure. Relevant biological responses to ozone for both repair-deficient Csb(-/-) and repair-proficient Csb(+/-) mice, as determined by biochemical analysis of bronchoalveolar lavage fluid (e.g., increases of polymorphonuclear neutrophils, alkaline phosphatase, macrophage-inflammatory protein-2, and tumor necrosis factor-alpha), pathological examinations, and gene expression (upregulation of oxidative-stress-related genes) analyses were observed. The bronchoalveolar lavage fluid showed significantly more tumor necrosis factor-alpha in repair-deficient Csb(-/-) mice than in repair-proficient Csb(+/-) mice after ozone exposure. In addition, a clear trend was observed toward fewer differentially expressed genes with a lower fold ratio in repair-deficient Csb(-/-) mice than in repair-proficient Csb(+/-) mice. However, repair-deficient Csb(-/-) mice do not respond significantly more sensitively to ozone compared with repair-proficient Csb(+/-) mice at the level of gene expression. We conclude that, under the conditions employed here, although small differences at the transcriptional level exist between repair-proficient Csb(+/-) mice and transcription-coupled repair defective Csb(-/-) mice, these do not have a significant effect on the ozone-induced lung injury.

Response of spontaneously hypertensive rats to inhalation of fine and ultrafine particles from traffic: experimental controlled study.

BACKGROUND: Many epidemiological studies have shown that mass concentrations of ambient particulate matter (PM) are associated with adverse health effects in the human population. Since PM is still a very crude measure, this experimental study has explored the role of two distinct size fractions: ultrafine (<0.15 microm) and fine (0.15- 2.5 microm) PM. In a series of 2-day inhalation studies, spontaneously hypersensitive (SH) rats were exposed to fine, concentrated, ambient PM (fCAP) at a city background location or a combination of ultrafine and fine (u+fCAP) PM at a location dominated by traffic. We examined the effect on inflammation and both pathological and haematological indicators as markers of pulmonary and cardiovascular injury. Exposure concentrations ranged from 399 microg/m3 to 3613 microg/m3 for fCAP and from 269 microg/m3 to 556 microg/m3 for u+fCAP. RESULTS: Ammonium, nitrate, and sulphate ions accounted for 56 +/- 16% of the total fCAP mass concentrations, but only 17 +/- 6% of the u+fCAP mass concentrations. Unambiguous particle uptake in alveolar macrophages was only seen after u+fCAP exposures. Neither fCAP nor u+fCAP induced significant changes of cytotoxicity or inflammation in the lung. However, markers of oxidative stress (heme oxygenase-1 and malondialdehyde) were affected by both fCAP and u+fCAP exposure, although not always significantly. Additional analysis revealed heme oxygenase-1 (HO-1) levels that followed a nonmonotonic function with an optimum at around 600 microg/m3 for fCAP. As a systemic response, exposure to u+fCAP and fCAP resulted in significant decreases of the white blood cell concentrations. CONCLUSION: Minor pulmonary and systemic effects are observed after both fine and ultrafine + fine PM exposure. These effects do not linearly correlate with the CAP mass. A greater component of traffic CAP and/or a larger proportion ultrafine PM does not strengthen the absolute effects.

Inhalation of concentrated particulate matter produces pulmonary inflammation and systemic biological effects in compromised rats.

Although significant progress has been made over the past few years, there is still debate on the causal fractions that are responsible for particulate matter (PM)-associated adverse health effects. A series of 1-d inhalation exposures to concentrated ambient particles (CAPs) were performed in compromised rats, focusing on pulmonary inflammation and changes in blood factors as biological outcomes. Studies were carried out in The Netherlands at an urban background location in Bilthoven, an industrialized location in the city of Utrecht, as well as at a location that is heavily dominated by freeway emissions. It was hypothesized that exposure to CAPs resulted in oxidative stress in the lung, producing a release of inflammatory mediators, which in turn can result in cardiovascular effects. Both spontaneously hypertensive rats and rats preexposed to ozone were studied. The effects were studied at 2d postexposure, focusing on pathology and cell proliferation, bronchoalveolar lavage fluid (BALF) analysis (including cytokines, biochemistry, cell differentials, cell viability and proliferation, and Clara-cell 16 protein), and blood analyses (fibrinogen, Clara-cell 16 protein, Von Willebrand factor, and cell differentials). Using CAPs exposures as a binary term, mild inflammation (increased numbers of neutrophils) and increased lung permeability (protein and albumin leakage in BALF) were evident. In addition, CAPs also produced increased fibrinogen concentrations in blood of spontaneously hypertensive rats. In conclusion, inhalation up to 3700 microg/m3 CAPs in the size range of 0.15-2.5 microm did induce statistically significant effects in the lung and blood, but the effects observed may not potentially be very biologically relevant. PM mass concentrations and lung permeability were weakly associated. This suggests that other PM metrics might be more appropriate.