Effect of ambient particulate matter exposure on hemostasis

Association Between Atrial Fibrillation and Occupational Exposure in Firefighters Based on Self-Reported Survey Data

Background Exposure to inhaled smoke, pollutants, volatile organic compounds, and polycyclic aromatic hydrocarbons in the firefighting environment has been associated with detrimental respiratory and cardiovascular effects, making firefighters a unique population with both personal and occupational risk factors for cardiovascular disease. Some of these exposures are also associated with development of atrial fibrillation. We aimed to study the association of atrial fibrillation and occupational exposure in firefighters. Methods and Results A cross-sectional survey was conducted between October 2018 and December 2019. Data were gathered electronically and stored in a secure REDCap database through Louisiana State University Health Shreveport. Firefighters who were members of at least 1 of 5 preselected professional organizations were surveyed via electronic links distributed by the organizations. The survey queried the number of fires fought per year as a measure of occupational exposure, as well as self-reported cardiovascular disease. A total of 10 860 active firefighters completed the survey, of whom 93.5% were men and 95.5% were aged ≤60 years. Firefighters who fought a higher number of fires per year had a significantly higher prevalence of atrial fibrillation (0-5 fires per year 2%, 6-10 fires per year 2.3%, 11-20 fires per year 2.7%, 21-30 fires per year 3%, 31 or more fires per year 4.5%; P<0.001). Multivariable logistic regression showed that a higher number of fires fought per year was associated with an increased risk of atrial fibrillation (odds ratio 1.14 [95% CI, 1.04-1.25]; P=0.006). Conclusions Firefighters may have an increased risk of atrial fibrillation associated with the number of fires they fight per year. Further clinical and translational studies are needed to explore causation and mechanisms.

Association between air particulate matter pollution and blood cell counts of women preparing for pregnancy: Baseline analysis of a national birth cohort in China

BACKGROUND

Limited evidence is known about whether long-term exposures to air borne particulate matters of 2.5 μm or less (PM_2.5) impact human hematologic index for women preparing for pregnancy. No study assessed the effect of PM₁, which is small enough to reach the blood circulation.

OBJECTIVE

To evaluate whether exposure to PM₁ and PM_2.5 is associated with blood cell count of woman preparing for pregnancy.

METHOD

Based on the baseline data of a national birth cohort in China, we analysed the white blood cell (WBC), red blood cells (RBC) and thrombocyte counts of 1,203,565 women who are aged 18-45 years, being Han ethnicity, had no chronic disease and preparing for pregnancy. We matched their home addresses and examination date with daily concentrations of PM₁ and PM_2.5 which were estimated by a machine learning method with remote sensing, meteorological and land use information. Generalized additive mixed model to examine the associations between exposure to one-year average exposure to PMs prior to the health examination and the blood cells counts, after adjustment for potential individual variables.

RESULTS

A 10 μg/m³ PM₁ increment was associated with -1.49% (95%CI: 1.56%, -1.42%) difference in WBC count; with 0.33% (95%CI: 0.30%, 0.36%) difference of RBC count; and with 1.08% (95%CI: 1.01%, 1.15%) difference of thrombocyte count. For PM_2.5, the corresponding difference was -0.47% (95%CI: 0.54%, -0.39%) for WBC; was 0.06% (95%CI: 0.03%, 0.09%) for RBC; and was 1.10% (95%CI: 1.02%, 1.18%) for thrombocyte. Women working as workers, being overweight and with tobacco smoking exposure had higher associations between PMs and hematologic index than their counterparts (p < 0.05 for interaction test).

CONCLUSION

Long-term exposure to PMs were associated with decrement in WBC, as well as increment in RBC and thrombocytes among Han Chinese women preparing for pregnancy. Measures such as using air purifiers and wearing a mask in polluted areas should be improved to prevent women from the impact of PMs.

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.

Venous thromboembolism in hospital emergency room. A retrospective study on climatic effect

Several cardiovascular conditions exhibit seasonality in frequency and mortality, but little is known about the seasonality of Venous ThromboEmbolism (VTE), a very relevant medical condition, and seasonal influences are still conflicting. Patients having co-morbidities, individual suffered from dyspnea, swelling, edema of lower limb, pain (chest, lower limbs) are admitted frequently to the hospital emergency room (HER), particularly. Both mark a potential risk for VTE, that can be increased also by seasonality. A four years retrospective analysis (2016-2019) was carried out in individuals and patients admitted to the HER of the Hospital of Catania (a Mediterranean city of Sicily, Italy) to evaluate the VTE frequency and its seasonal differences, common symptoms, potential usage of some common laboratory tests. Dyspnea, swelling, edema of lower limb and pain (chest, lower limbs) were considered to suspect pulmonary embolism (PE) or for deep vein thrombosis of lower limb (DVT). Platelet count, platelet volume, fibrinogen, C-reactive protein, and D-dimer were considered. VTE frequency per year was 2.9/10,000 (2016), 4.9/10,000 (2017) 3.6/10,000 (2018), and 5.1/10,000 (2019) respectively. Dyspnea was highly frequent for PE, edema and lower limb pain were frequent in DVT patients. Fibrinogen, C reactive protein, and D-dimer values were found raised in all the VTE patients. Platelet volume was found higher in DVT than PE VTE events that occurred in warm periods were modestly greater (57 VTE: 38 DVT, 19 PE) compared to cold months (52 VTE: 34 DVT, 18 PE). Our results could be explained by the increased sweating due to the high temperatures, which in turn, can affect both on plasma concentration and on hematocrit value coupled to the reduction in atmospheric pressure determining both a hyper-coagulative condition. Climate seasonal characteristics, and environmental conditions in Catania city (Sicily) may be as reasonable items in expecting on different VTE rates in warm period compared to cold. This study highlights no specific symptoms, and confirms the common lab tests for individuals and patients admitted to HER as simple and helpful tools in initiating none or mini-invasive diagnostic strategy for the VTE. Finally, the climate/seasonality coupled with latitude can have a direct influence on the incidence of DVT.

Exposure to organic and inorganic traffic-related air pollutants alters haematological and biochemical indices in albino mice Mus musculus

The relationship between air pollution exposure and haematology remains controversial. Evidences in the effect of trace organic air pollutants and in the impact of such exposure on lipid and protein levels are scarce. This work investigated the health effects of medium-term exposure to traffic-related air pollution on both haematological and biochemical indices in animal models. Two groups of albino mice (Mus musculus) were exposed to ambient air polluted by vehicle exhaust for three and six months, and one group was kept as control. Results found significant depletions (p < 0.05) in red blood cells, packed cell volume, neutrophils, eosinophils, monocytes, and total cholesterol after air pollution exposure. On the contrary, significant elevations (p < 0.05) were observed in platelet, lymphocytes, and serum albumin compared to control condition. Correlation data suggested that significant changes in blood parameters may be altered by the synergistic effect of several organic and inorganic air pollutants.

A Comparative In Vivo Scrutiny of Biosynthesized Copper and Zinc Oxide Nanoparticles by Intraperitoneal and Intravenous Administration Routes in Rats

During the present time, anti-microbial features of copper (Cu) and zinc oxide (ZnO) nanoparticles (NPs) are extensively used to combat the growth of pathogenic microbes. CuNPs and ZnONPs are recurrently used in cosmetics, medicine and food additives, and their potential for toxic impacts on human and ecosystem is of high concern. In this study, the fate and toxicity of 16- to 96-nm-ranged biosynthesized copper (Bio-CuNPs) and zinc oxide (Bio-ZnONPs) was assessed in male Wistar rats. In vivo exposures of the two nanoparticles are achieved through two different administration routes namely, intraperitoneal (i/p) and intravenous (i/v) injections. The three different concentrations, no observable adverse effect concentration (NOAEC), inhibitory concentration (IC₅₀) and total lethal concentration (TLC), were appraised at the dose range of 6.1 to 19.82 μg/kg and 11.14 to 30.3 μg/kg for Bio-CuNPs and Bio-ZnONPs respectively, for both i/p and i/v routes on 14th and 28th day of observation. These dose ranges are considered based on the previous study of antibacterial dose on multidrug-resistant pathogenic bacteria. In this study, we investigated the toxic effect of Bio-CuNPs and Bio-ZnONPs on animal behaviour, animal mass, haematologic indices, organ indices and histopathology of liver, spleen, kidney and brain organs. We found that i/v and i/p administration of Bio-ZnONPs in three different doses did not cause mortality and body weight was slightly reduced up to second week of administration compared with the vehicle control group. At the dose ranges of 11-16 μg/kg (i/v) and 24-30 μg/kg (i/p), no significant changes were observed in the serum creatinine level as well as serum ALT, serum AST level and ALP level which were 40.7 mg/dl, 37.9 IU/L and 82.4 IU/L normal as compared to vehicle control on 14th and 28th day of observation. These findings are confirmed in liver, kidney and spleen indices and histopathology studies. Furthermore, liver and kidney injury occurred when the concentrations of Bio-CuNPs were at 9.5 μg/kg (IC₅₀) and 11.7 μg/kg (TLC) for i/v route of administration. Similarly, increase in serum ALT (67.7 mg/dl), AST level (70 IU/L) and ALP (128 IU/L) was also observed. And the body weight was significantly lower than in the control group after 14th day, and there were statistically significant differences observed by this route; interestingly, the toxicity of Bio-CuNPs in serum is prolonged (up to 28th day). Effect of Bio-CuNPs through i/p route was considerably low as compare to the control. Results of the present study revealed that Bio-ZnONPs have no effect on kidney and liver function biomarkers (both i/v and i/p) as compared to Bio-CuNPs. Graphical abstract As shown in graphical abstract (Fig. 1), our aim is to assess the toxicity of Bio-CuNPs and Bio-ZnONPs through in vivo protocol. According to Kahru and Dubourguier reviews, AgNPs, CuNPs and ZnONPs have been historically used as biocides, for preventing the growth of microorganisms and algae (Kahru and Dubourguier 2010). Therefore, as like pesticides, nanomaterials should be monitored for their toxic response toward non-target species, including humans and animals. To gain a better understanding whether the accidental release of metal-containing NPs may pose a threat to non-target species, assessing of toxic effect is indispensable.The 'non-target organism' is an organism which will be exposed to NPs after their incidental release into the environment.

Effects of Diesel Exhaust on Cardiovascular Function and Oxidative Stress

SIGNIFICANCE

Air pollution is a major global health concern with particulate matter (PM) being especially associated with increases in cardiovascular morbidity and mortality. Diesel exhaust emissions are a particularly rich source of the smallest sizes of PM ("fine" and "ultrafine") in urban environments, and it is these particles that are believed to be the most detrimental to cardiovascular health. Recent Advances: Controlled exposure studies to diesel exhaust in animals and man demonstrate alterations in blood pressure, heart rate, vascular tone, endothelial function, myocardial perfusion, thrombosis, atherogenesis, and plaque stability. Oxidative stress has emerged as a highly plausible pathobiological mechanism by which inhalation of diesel exhaust PM leads to multiple facets of cardiovascular dysfunction.

CRITICAL ISSUES

Diesel exhaust inhalation promotes oxidative stress in several biological compartments that can be directly associated with adverse cardiovascular effects.

FUTURE DIRECTIONS

Further studies with more sensitive and specific in vivo human markers of oxidative stress are required to determine if targeting oxidative stress pathways involved in the actions of diesel exhaust PM could be of therapeutic value. Antioxid. Redox Signal. 28, 819-836.

Air Pollution and Other Environmental Modulators of Cardiac Function

Cardiovascular disease (CVD) is the leading cause of death in developed regions and a worldwide health concern. Multiple external causes of CVD are well known, including obesity, diabetes, hyperlipidemia, age, and sedentary behavior. Air pollution has been linked with the development of CVD for decades, though the mechanistic characterization remains unknown. In this comprehensive review, we detail the background and epidemiology of the effects of air pollution and other environmental modulators on the heart, including both short- and long-term consequences. Then, we provide the experimental data and current hypotheses of how pollution is able to cause the CVD, and how exposure to pollutants is exacerbated in sensitive states. Published 2017. Compr Physiol 7:1479-1495, 2017.

Hemocompatibility of inhaled environmental nanoparticles: Potential use of in vitro testing

Hemocompatibility testing is an important part in the evaluation of nano-based medicines. However, it is not systematically used for the assessment of environmental particles since they do not come in contact with blood immediately. Studies on human exposure to air-borne particles and pulmonary exposure of rodents have reported alterations in blood physiology. It is not clear, whether these effects are majorly caused by tissue inflammation or translocated particles in blood. This review addresses the question, if in vitro hemocompatibility testing could help in the risk evaluation of inhaled particles. Particle blood concentrations were estimated based on exposure levels, ventilation volume, deposition rate, lung surface area, and permeability of the alveolar epithelium to particles. The categories of hemocompatibility, thrombosis, coagulation, platelets, hematology, and immunology, were introduced. Also, concentrations of ultrafine particles, silver nanoparticles, carbon nanotubes that caused adverse effects in human blood samples were compared to the estimated concentrations of translocated particles. The comparison suggested that, it is unlikely for translocated nanoparticles to be the sole cause of adverse blood effects. Nevertheless, the testing of specific hemocompatibility parameters (hemolysis and clotting) in healthy blood might help to compare biological effect of inhaled particles containing different amounts of contamination. Testing of samples from healthy and diseased persons might help to identify pathological dispositions that increase the possibility of adverse reaction of nanoparticles in blood.

Individual PM2.5 exposure is associated with the impairment of cardiac autonomic modulation in general residents

Fine particulate matter (PM2.5) is one of the major pollutants in metropolitan areas. The current study was conducted to observe the effects of PM2.5 on cardiac autonomic modulation. The participants included 619 men and women aged from 35-75 in a residential area in Shanghai, China. All the participants were divided into four categories according to the distance between their apartments and major road. In addition, individual PM2.5 was measured using SIDEPAKTM AM510 (TSI, USA) from 8:00 am to 6:00 pm. At the end of the individual PM2.5 measurement, the systolic pressure, diastolic pressure, heart rate (HR), low-frequency (LF), high-frequency (HF), and LF/HF were determined. The association between individual PM2.5 level and the above health effects was analyzed using generalized linear regression. The results showed that the average concentration of individual PM2.5 was 95.5 and 87.0 μg/m(3) for men and women. Residential distance to major road was negatively correlated with the individual PM2.5. The results indicated that per 1.0 μg/m(3) increase of individual PM2.5 was associated with a 2.3 % increase for systolic pressure, 0.3 % increase for diastolic pressure, 0.4 % decrease for LF, and 0.4 % decrease for HF. Nevertheless, there was no statistical association between individual PM2.5 and heart rate and LF/HF in the total model. In addition, the similar results were found in men and women excluding a significant association between PM2.5 and the heart rate in men. The alterations of cardiac autonomic modulation hinted that PM2.5 exposure might be associated with the potential occurrence of cardiovascular disease, such as arrhythmia and ischemic heart diseases.

Platelet activation independent of pulmonary inflammation contributes to diesel exhaust particulate-induced promotion of arterial thrombosis

BACKGROUND

Accelerated thrombus formation induced by exposure to combustion-derived air pollution has been linked to alterations in endogenous fibrinolysis and platelet activation in response to pulmonary and systemic inflammation. We hypothesised that mechanisms independent of inflammation contribute to accelerated thrombus formation following exposure to diesel exhaust particles (DEP).

METHODS

Thrombosis in rats was assessed 2, 6 and 24 h after administration of DEP, carbon black (CB; control carbon nanoparticle), DQ12 quartz microparticles (to induce pulmonary inflammation) or saline (vehicle) by either intra-tracheal instillation (0.5 mg, except Quartz; 0.125 mg) or intravenous injection (0.5 mg/kg). Thrombogenicity was assessed by carotid artery occlusion, fibrinolytic variables and platelet-monocyte aggregates. Measures of inflammation were determined in plasma and bronchoalveolar lavage fluid. Tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI)-1 were measured following direct in vitro exposure of human umbilical vein endothelial cells (HUVECs) to DEP (10-150 μg/mL).

RESULTS

Instillation of DEP reduced the time to thrombotic occlusion in vivo, coinciding with the peak of DEP-induced pulmonary inflammation (6 h). CB and DQ12 produced greater inflammation than DEP but did not alter time to thrombotic occlusion. Intravenous DEP produced an earlier (2 h) acceleration of thrombosis (as did CB) without pulmonary or systemic inflammation. DEP inhibited t-PA and PAI-1 release from HUVECs, and reduced the t-PA/PAI-1 ratio in vivo; similar effects in vivo were seen with CB and DQ12. DEP, but not CB or DQ12, increased platelet-monocyte aggregates.

CONCLUSION

DEP accelerates arterial thrombus formation through increased platelet activation. This effect is dissociated from pulmonary and systemic inflammation and from impaired fibrinolytic function.

Evaluation of atherosclerosis as a potential mode of action for cardiovascular effects of particulate matter

Epidemiology studies have consistently reported associations between PM2.5 exposure and cardiovascular (CV) morbidity and mortality, but the epidemiology evidence for associations between PM2.5 and subclinical measures of atherosclerosis is unclear. We critically reviewed the experimental studies of PM2.5 and effects associated with acceleration and exacerbation of atherosclerosis and evaluated whether they support a biologically plausible, human-relevant mode of action (MoA) for the associations between PM2.5 exposure and adverse CV outcomes reported in epidemiology studies. We focused on outcomes related to atherosclerotic plaque development, thrombosis, and coagulation, and we examined whether these outcomes were correlated with measures of oxidative stress and systemic or pulmonary inflammation, to evaluate whether these processes are likely to be key early events for atherogenic effects of PM. While the current experimental evidence indicates that the acceleration and exacerbation of atherosclerosis is a biologically plausible MoA in experimental animal models, we found that the human relevance of the key events in the proposed MoA is unclear and not well supported by the existing data. Further studies are needed to fill several important data gaps before the human relevance of this MoA can be established.

Milan PM1 induces adverse effects on mice lungs and cardiovascular system

Recent studies have suggested a link between inhaled particulate matter (PM) exposure and increased mortality and morbidity associated with cardiorespiratory diseases. Since the response to PM1 has not yet been deeply investigated, its impact on mice lungs and cardiovascular system is here examined. A repeated exposure to Milan PM1 was performed on BALB/c mice. The bronchoalveolar lavage fluid (BALf) and the lung parenchyma were screened for markers of inflammation (cell counts, tumor necrosis factor-α (TNF-α); macrophage inflammatory protein-2 (MIP-2); heme oxygenase-1 (HO-1); nuclear factor kappa-light-chain-enhancer of activated B cells p50 subunit (NFκB-p50); inducible nitric oxide synthetase (iNOS); endothelial-selectin (E-selectin)), cytotoxicity (lactate dehydrogenase (LDH); alkaline phosphatase (ALP); heat shock protein 70 (Hsp70); caspase-8-p18), and a putative pro-carcinogenic marker (cytochrome 1B1 (Cyp1B1)). Heart tissue was tested for HO-1, caspase-8-p18, NFκB-p50, iNOS, E-selectin, and myeloperoxidase (MPO); plasma was screened for markers of platelet activation and clot formation (soluble platelet-selectin (sP-selectin); fibrinogen; plasminogen activator inhibitor 1 (PAI-1)). PM1 triggers inflammation and cytotoxicity in lungs. A similar cytotoxic effect was observed on heart tissues, while plasma analyses suggest blood-endothelium interface activation. These data highlight the importance of lung inflammation in mediating adverse cardiovascular events following increase in ambient PM1 levels, providing evidences of a positive correlation between PM1 exposure and cardiovascular morbidity.

Seasonal influences on CAPs exposures: differential responses in platelet activation, serum cytokines and xenobiotic gene expression

Increasing evidence suggests a role for a systemic pro-coagulant state in the pathogenesis of cardiac dysfunction subsequent to inhalation of airborne particulate matter (PM). We evaluated platelet activation, systemic cytokines and pulmonary gene expression in mice exposed to concentrated ambient particulate matter (CAPs) in the summer of 2008 (S08) and winter of 2009 (W09) from the San Joaquin Valley of California, a region with severe PM pollution episodes. Additionally, we characterized the PM from both exposures including organic compounds, metals, and polycyclic aromatic hydrocarbons. Mice were exposed to an average of 39.01 μg/m(3) of CAPs in the winter and 21.7 μg/m3 CAPs in the summer, in a size range less than 2.5 μm for 6 h/day for 5 days per week for 2 weeks. Platelets were analyzed by flow cytometry for relative size, shape, CD41, P-selectin and lysosomal associated membrane protein-1 (LAMP-1) expression. Platelets from W09 CAPs-exposed animals had a greater response to thrombin stimulation than platelets from S08 CAPs-exposed animals. Serum cytokines were analyzed by bead based immunologic assays. W09 CAPs-exposed mice had elevations in IL-2, MIP-1α, and TNFα. Laser capture microdissection (LCM) of pulmonary vasculature, parenchyma and airways all showed increases in CYP1a1 gene expression. Pulmonary vasculature showed increased expression of ICAM-1 and Nox-2. Our findings demonstrate that W09 CAPs exposure generated a greater systemic pro-inflammatory and pro-coagulant response to inhalation of environmentally derived fine and ultrafine PM. Changes in platelet responsiveness to agonists, seen in both exposures, strongly suggests a role for platelet activation in the cardiovascular and respiratory effects of particulate air pollution.

Epigenetic Regulation in Particulate Matter-Mediated Cardiopulmonary Toxicities: A Systems Biology Perspective

Particulate matter (PM) air pollution exerts significant adverse health effects in global populations, particularly in developing countries with extensive air pollution. Understanding of the mechanisms of PM-induced health effects including the risk for cardiovascular diseases remains limited. In addition to the direct cellular physiological responses such as mitochondrial dysfunction and oxidative stress, PM mediates remarkable dysregulation of gene expression, especially in cardiovascular tissues. The PM-mediated gene dysregulation is likely to be a complex mechanism affected by various genetic and non-genetic factors. Notably, PM is known to alter epigenetic markers (e.g., DNA methylation and histone modifications), which may contribute to air pollution-mediated health consequences including the risk for cardiovascular diseases. Notably, epigenetic changes induced by ambient PM exposure have emerged to play a critical role in gene regulation. Though the underlying mechanism(s) are not completely clear, the available evidence suggests that the modulated activities of DNA methyltransferase (DNMT), histone acetylase (HAT) and histone deacetylase (HDAC) may contribute to the epigenetic changes induced by PM or PM-related chemicals. By employing genome-wide epigenomic and systems biology approaches, PM toxicogenomics could conceivably progress greatly with the potential identification of individual epigenetic loci associated with dysregulated gene expression after PM exposure, as well the interactions between epigenetic pathways and PM. Furthermore, novel therapeutic targets based on epigenetic markers could be identified through future epigenomic studies on PM-mediated cardiopulmonary toxicities. These considerations collectively inform the future population health applications of genomics in developing countries while benefiting global personalized medicine at the same time.

Multi-walled carbon nanotube directed gene and protein expression in cultured human aortic endothelial cells is influenced by suspension medium

The use and production of multi-walled carbon nanotubes (MWCNTs) have significantly increased over the last decade due to their versatility in numerous applications. Their unique physical and chemical properties make them desirable for various biomedical applications, but the same properties also raise concerns about their safety to human health, particularly at the cellular level. The vascular endothelium could be exposed to nanomaterials either by direct intravenous administration in nanomedicine or by translocation following inhalational exposure in an occupational setting. We hypothesized that direct exposure to MWCNTs will increase the expression of inflammatory markers in human aortic endothelial cells (HAEC). We also investigated the effect of the route of exposure on activation by changing the suspension medium of the MWCNTs. HAEC were treated in vitro with MWCNTs (1 or 10 μg/cm(2)) suspended in either cell culture medium [(M)-MWCNTs] or 10% clinical grade pulmonary surfactant [(S)-MWCNTs]. The zeta potential of the (S)-MWCNTs was significantly more negative than the (M)-MWCNTs suggesting a more stable suspension. Treatment of HAEC with (S)-MWCNTs; as compared to (M)-MWCNTs resulted in a significantly higher up-regulation of mRNA transcripts for cell adhesion molecules VCAM1, SELE, ICAM1 and the chemokine CCL2. Time dependent changes in VCAM1 and CCL2 protein levels were confirmed by immunofluorescence, flow cytometry and ELISA. A label free quantitative mass spectrometry proteomic analysis was utilized to compare protein expression patterns between the two suspensions of MWCNTs. We identified significant expression changes in >200 unique proteins in MWCNT treated HAEC. However, the two suspensions of MWCNTs resulted in different protein expression patterns with the eIF2 pathway as the only common pathway identified between the two suspensions. These data suggest that direct exposure to MWCNTs induces acute inflammatory and protein expression changes in HAEC, which is influenced by the type of media used for suspension of MWCNTs and their resulting zeta potential.

Manufactured and airborne nanoparticle cardiopulmonary interactions: a review of mechanisms and the possible contribution of mast cells

Human inhalation exposures to manufactured nanoparticles (NP) and airborne ultrafine particles (UFP) continues to increase in both occupational and environmental settings. UFP exposures have been associated with increased cardiovascular mortality and morbidity, while ongoing research supports adverse systemic and cardiovascular health effects after NP exposures. Adverse cardiovascular health effects include alterations in heart rate variability, hypertension, thrombosis, arrhythmias, increased myocardial infarction, and atherosclerosis. Exactly how UFP and NP cause these negative cardiovascular effects is poorly understood, however a variety of mediators and mechanisms have been proposed. UFP and NP, as well as their soluble components, are known to systemically translocate from the lung. Translocated particles could mediate cardiovascular toxicity through direct interactions with the vasculature, blood, and heart. Recent study suggests that sensory nerve stimulation within the lung may also contribute to UFP- and NP-induced acute cardiovascular alterations. Activation of sensory nerves, such as C-fibers, within the lung may result in altered cardiac rhythm and function. Lastly, release of pulmonary-derived mediators into systemic circulation has been proposed to facilitate cardiovascular effects. In general, these proposed pulmonary-derived mediators include proinflammatory cytokines, oxidatively modified macromolecules, vasoactive proteins, and prothrombotic factors. These pulmonary-derived mediators have been postulated to contribute to the subsequent prothrombotic, atherogenic, and inflammatory effects after exposure. This review will evaluate the potential contribution of individual mediators and mechanisms in facilitating cardiopulmonary toxicity following inhalation of UFP and NP. Lastly, we will appraise the literature and propose a hypothesis regarding the possible role of mast cells in contributing to these systemic effects.

Sirt1 protects against thrombomodulin down-regulation and lung coagulation after particulate matter exposure

Exposure to ambient particulate matter (PM) air pollution has been reported to trigger inflammation and thrombosis. However, molecular mechanisms underlying the modulation of coagulation pathways in PM-induced thrombosis remain largely unknown. We report here that Sirt1, a member of class III histone deacetylase, controls lung inflammation and coagulation after PM exposure. Sirt1 knock-out mice exhibited aggravated lung vascular leakage and inflammation after PM exposure, which was correlated with increased NF-κB acetylation and activation. Furthermore, Sirt1 knock-out mice were highly susceptible to PM-induced lung coagulation as demonstrated by increased fibrin formation. The increased fibrin formation was associated with reduced tissue factor pathway inhibitor (TFPI) expression and increased plasminogen activator inhibitor-1 (PAI-1) activity in the lungs, thus favoring elevated coagulation and disrupted fibrinolysis responses. Thrombomodulin (TM), a central player of the anticoagulant protein C system, is regulated by Kruppel-like factor 2 (KLF2) at the transcriptional level. Our data show that PM exposure led to decreased lung KLF2 and TM expression in wild-type mice, and lung KLF2 and TM protein levels were further decreased in Sirt1 knock-out mice. Importantly, Sirt1 gene delivery inhibited TM and KLF2 down-regulation and reduced lung coagulation after PM exposure. Collectively, our studies indicate that Sirt1 functions as a suppressor of coagulation after particulate matter exposure.

Multi-walled carbon nanotubes inhibit regenerative axon growth of dorsal root ganglia neurons of mice

Recent observations have demonstrated that nanomaterials may be toxic to human tissue. While the ability of nano-scaled particulate matter is known to cause a range of problems in respiratory system, recent observations suggest that the nervous system may be vulnerable as well. In the current paper we asked whether exposure of primary neuronal cell cultures to nanoparticles might compromise regenerative axon growth. Regenerative response was triggered by performing a conditioning lesion of sciatic nerve five days prior to collection of dorsal root ganglia (DRG). DRG neurons were plated at a low density and incubated with multi-walled carbon nanotubes (MWCNTs) (0.1-10 μg/ml in 10% of surfactant in saline) overnight. The experiments showed that exposure of DRG cultures to MWCNT significantly impaired regenerative axonogenesis without concomitant cell death. These results indicate that MWNCTs may have detrimental effect on nerve regeneration and may potentially trigger axonal pathology.

The effect of air pollution on haemostasis

Ambient environmental air pollutants include gaseous and particulate components. In polluted air, especially particulate matter seems responsible for cardiovascular complications: It consists of a heterogeneous mixture of solid and liquid particles with different diameters ranging from large thoracic to ultrafine particles, with a diameter <100 nm. Ultrafines can penetrate deeply into the lung to deposit in the alveoli. Cardiovascular manifestations result both from short-term and long-term exposure and have been linked to interference with the autonomic nervous system, direct translocation into the systemic circulation, pulmonary inflammation and oxidative stress. Thrombotic complications associated with air pollution comprise arterial and probably venous thrombogenicity. This review describes the existing epidemiological and experimental evidence to explain the rapid induction of myocardial infarction within 1-2 hours after exposure to polluted air and advances several explanations as to why more chronic exposure will lead to enhanced venous thrombogenicity. Mechanisms such as platelet activation, endothelial dysfunction, coagulation factor changes and microvesicle production are discussed.

Factor XII activation is essential to sustain the procoagulant effects of particulate matter

BACKGROUND

Particulate matter (PM) is a key component of ambient air pollution and has been associated with an increased risk of thrombotic events and mortality. The underlying mechanisms remain unclear.

OBJECTIVES

 To study the mechanisms of PM-driven procoagulant activity in human plasma and to investigate mainly, the coagulation driven by ultrafine particles (UFPs; < 0.1 μm) in genetically modified mice.

METHODS

Thrombin generation in response to PM of different sizes was assessed in normal human platelet-poor plasma, as well as in plasmas deficient in the intrinsic pathway proteases factors XII (FXII) or XI (FXI). In addition, UFPs were intratracheally instilled in wild-type (WT) and FXII-deficient (FXII(-/-) ) mice and plasma thrombin generation was analyzed in plasma from treated mice at 4 and 20 h post-exposure.

RESULTS

In normal human plasma, thrombin generation was enhanced in the presence of PM, whereas PM-driven thrombin formation was completely abolished in FXII- and FXI-deficient plasma. UFPs induced a transient increase in tissue factor (TF)-driven thrombin formation at 4 h post-instillation in WT mice compared with saline instillation. Intratracheal instillation of UFPs resulted in a procoagulant response in WT mice plasma at 20 h, whereas it was entirely suppressed in FXII(-/-) mice.

CONCLUSIONS

 Overall, the data suggest that PM promotes its early procoagulant actions mostly through the TF-driven extrinsic pathway of coagulation, whereas PM-driven long lasting thrombogenic effects are predominantly mediated via formation of activated FXII. Hence, FXII-driven thrombin formation may be relevant to an enhanced thrombotic susceptibility upon chronic exposure to PM in humans.

Differential cardiopulmonary effects of size-fractionated ambient particulate matter in mice

A growing body of evidence from epidemiological and toxicological studies provides a strong link between exposure to ambient particulate matter (PM) of varying size and increased cardiovascular and respiratory morbidity and mortality. This study was designed to evaluate the cardiopulmonary effects of ambient coarse, fine, and ultrafine particles collected in Chapel Hill, NC. Mice were exposed to each size fraction by oropharyngeal instillation. Twenty-four hours later, pulmonary inflammation was assessed by bronchoalveolar lavage and cardiac injury was measured using a Langendorff cardiac perfusion preparation. Recovery of post-ischemic left ventricular developed pressure and infarct size were measured as indeces of cardiac ischemia/reperfusion injury. Coronary flow rate was measured before, during, and after ischemia. We demonstrate that coarse PM caused the most significant pulmonary inflammatory responses. In contrast, hearts from ultrafine-exposed mice had significantly lower post-ischemic functional recovery and greater infarct size, while hearts from coarse and fine PM-exposed mice had no significant responses to ischemia/reperfusion. The coronary flow rate was significantly reduced in the ultrafine PM group. This study shows that exposure of mice to coarse PM results in significant pulmonary toxicity while ultrafine PM appears to enhance cardiac ischemia/reperfusion injury.

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.

Pneumoproteins and inflammatory biomarkers in asphalt pavers

Pneumoproteins, biomarkers of systemic inflammation and endothelial activation were studied across a season in 72 asphalt pavers, 32 asphalt plant operators and 19 asphalt engineers. Smokers had lower concentrations of Clara cell protein (CC-16) and surfactant protein A, but higher concentrations of surfactant protein D, interleukin 6, C-reactive protein, fibrinogen and intercellular adhesion molecule (ICAM)-1 than non-smokers. Smokers reporting wheezing had lower mean CC-16 concentration than smokers not reporting wheezing (5.7 vs 8.6 microg l(-1); p = 0.05). Cholesterol, P-selectin and ICAM-1 were lower in pavers and operators at the end compared with the start of the season. This may be related to increased physical activity during the season.

Short-term exposure to particulate matter induces arterial but not venous thrombosis in healthy mice

BACKGROUND

Epidemiological findings suggest an association between exposure to particulate matter (PM) and venous thrombo-embolism.

OBJECTIVES

  To investigate arterial vs. venous thrombosis, inflammation and coagulation in mice, (sub)acutely exposed to two types of PM.

METHODS

Various doses (25, 100 and 200 μg per animal) of urban particulate matter (UPM) or diesel exhaust particles (DEP) were intratracheally (i.t.) instilled in C57Bl6/n mice and several endpoints measured at 4, 10 and 24 h. Mice were also repeatedly exposed to 100 μg per animal on three consecutive days with endpoints measured 24 h after the last instillation.

RESULTS

Exposure to 200 μg per mouse UPM enhanced arterial thrombosis, but neither UPM nor DEP significantly enhanced venous thrombosis. Both types of PM induced dose-dependent increases in broncho-alveolar lavage fluid (BALF) total cell numbers (mainly neutrophils) and cytokines (IL-6, KC, MCP-1, RANTES, MIP-1α), with peaks at 4 h and overall higher values for UPM than for DEP. Systemic inflammation was limited to increased serum IL-6 levels, 4 h after UPM. Both types of PM induced similar and dose-dependent but modest increases in factor (F)VII, FVIII and fibrinogen. Three repeated instillations did not or only modestly enhance the proinflammatory and procoagulant status.

CONCLUSIONS

Compared with DEP, UPM induced more pronounced pulmonary inflammation, but both particle types triggered similar and mild short-term systemic effects. Hence, acute exposure to PM triggers activation of primary hemostasis in the mouse, but no substantial secondary hemostasis activation, resulting in arterial but not venous thrombogenicity.

Regulation of plasminogen activator inhibitor-1 expression in endothelial cells with exposure to metal nanoparticles

Recent studies demonstrated that exposure to nanoparticles could enhance the adhesion of endothelial cells and modify the membrane structure of vascular endothelium. The endothelium plays an important role in the regulation of fibrinolysis, and imbalance of the fibrinolysis system potential contributes to the development of thrombosis. Plasminogen activator inhibitor-1 (PAI-1) is the most potent endogenous inhibitor of fibrinolysis and is involved in the pathogenesis of several cardiovascular diseases. The aim of this study was to investigate the alteration of PAI-1 expression in mouse pulmonary microvascular endothelial cells (MPMVEC) exposed to the metal nanoparticles that are known to be reactive, and the potential underlying mechanisms. We compared the alteration of PAI-1 expression in MPMVEC exposed to non-toxic doses of nano-size copper (II) oxide (Nano-CuO) and nano-size titanium dioxide (Nano-TiO(2)). Our results showed that Nano-CuO caused a dose- and time-dependent increase in PAI-1 expression. Moreover, exposure of MPMVEC to Nano-CuO caused reactive oxygen species (ROS) generation that was abolished by pre-treatment of cells with ROS scavengers or inhibitors, DPI, NAC and catalase. Exposure of MPMVEC to Nano-CuO also caused a dose- and time-dependent increase in p38 phosphorylation by Western blot. These effects were significantly attenuated when MPMVEC were pre-treated with DPI, NAC and catalase. To further investigate the role of p38 phosphorylation in Nano-CuO-induced PAI-1 overexpression, the p38 inhibitor, SB203580, was used to pre-treat cells prior to Nano-CuO exposure. We found that Nano-CuO-induced overexpression of PAI-1 was attenuated by p38 inhibitor pre-treatment. However, Nano-TiO(2) did not show the same results. Our results suggest that Nano-CuO caused up-regulation of PAI-1 in endothelial cells is mediated by p38 phosphorylation due to oxidative stress. These findings have important implications for understanding the potential health effects of metal nanoparticle exposure.

Particulate matter air pollution and cardiovascular disease: An update to the scientific statement from the American Heart Association

In 2004, the first American Heart Association scientific statement on "Air Pollution and Cardiovascular Disease" concluded that exposure to particulate matter (PM) air pollution contributes to cardiovascular morbidity and mortality. In the interim, numerous studies have expanded our understanding of this association and further elucidated the physiological and molecular mechanisms involved. The main objective of this updated American Heart Association scientific statement is to provide a comprehensive review of the new evidence linking PM exposure with cardiovascular disease, with a specific focus on highlighting the clinical implications for researchers and healthcare providers. The writing group also sought to provide expert consensus opinions on many aspects of the current state of science and updated suggestions for areas of future research. On the basis of the findings of this review, several new conclusions were reached, including the following: Exposure to PM <2.5 microm in diameter (PM(2.5)) over a few hours to weeks can trigger cardiovascular disease-related mortality and nonfatal events; longer-term exposure (eg, a few years) increases the risk for cardiovascular mortality to an even greater extent than exposures over a few days and reduces life expectancy within more highly exposed segments of the population by several months to a few years; reductions in PM levels are associated with decreases in cardiovascular mortality within a time frame as short as a few years; and many credible pathological mechanisms have been elucidated that lend biological plausibility to these findings. It is the opinion of the writing group that the overall evidence is consistent with a causal relationship between PM(2.5) exposure and cardiovascular morbidity and mortality. This body of evidence has grown and been strengthened substantially since the first American Heart Association scientific statement was published. Finally, PM(2.5) exposure is deemed a modifiable factor that contributes to cardiovascular morbidity and mortality.

Effects of particulate matter (PM(10), PM(2.5) and PM(1)) on the cardiovascular system

Several studies have demonstrated that exposure to particulate matter (PM) of different size fractions is associated with an increased risk of cardiovascular disease (CVD). In this review, we have taken into consideration the possible correlation between the "short term" and "long term" effects of PM exposure and the onset of CVDs as well as the possible molecular mechanisms by which PM elicits the development of these events. Particularly, it is here underlined that these adverse health effects depend not only on the level of PM concentration in the air but also on its particular internal composition. Furthermore, we have also synthesized the findings gleaned from those few studies indicating that PM produced by tobacco smoke can give rise to cardiovascular injury.

Concentrated ambient ultrafine particle exposure induces cardiac changes in young healthy volunteers

RATIONALE

Exposure to ambient ultrafine particles has been associated with cardiopulmonary toxicity and mortality. Adverse effects specifically linked to ultrafine particles include loss of sympathovagal balance and altered hemostasis.

OBJECTIVES

To characterize the effects of acute exposure to ambient ultrafine particles in young healthy humans.

METHODS

Nineteen healthy nonsmoking male and female subjects between the ages of 18 and 35 were exposed to filtered air or to an atmosphere in which captured ultrafine (<0.16 microm) particles were concentrated by a factor of up to 20-fold over ambient levels with the use of particle concentrators fitted with size-selective outlets (ultrafine concentrated ambient particles [UFCAPs]). Subjects underwent bronchoalveolar lavage 18 hours after each exposure. Cardiovascular endpoints measured included pulmonary function, clinical chemistry, and hematological parameters, as well as heart rate variability and repolarization indices.

MEASUREMENTS AND MAIN RESULTS

Exposure to UFCAPs was statistically associated with an increase in frequency domain markers of heart rate variability, specifically indicative of elevated vagal input to the heart. Consistent with this finding were increases in the variance associated with the duration of the QT interval. In addition, UFCAP exposure resulted in a significant increase in blood levels of the fibrin degradation product D-dimer as well as a modest elevation in the inflammatory chemokine IL-8 recovered in the lavage fluid.

CONCLUSIONS

These findings show mild inflammatory and prothrombic responses and are suggestive of alterations in cardiac repolarization induced by UFCAP inhalation.

Exposure to ultrafine carbon particles at levels below detectable pulmonary inflammation affects cardiovascular performance in spontaneously hypertensive rats

BACKGROUND

Exposure to particulate matter is a risk factor for cardiopulmonary disease but the underlying molecular mechanisms remain poorly understood. In the present study we sought to investigate the cardiopulmonary responses on spontaneously hypertensive rats (SHRs) following inhalation of UfCPs (24 h, 172 mug.m-3), to assess whether compromised animals (SHR) exhibit a different response pattern compared to the previously studied healthy rats (WKY).

METHODS

Cardiophysiological response in SHRs was analyzed using radiotelemetry. Blood pressure (BP) and its biomarkers plasma renin-angiotensin system were also assessed. Lung and cardiac mRNA expressions for markers of oxidative stress (hemeoxygenase-1), blood coagulation (tissue factor, plasminogen activator inhibitor-1), and endothelial function (endothelin-1, and endothelin receptors A and B) were analyzed following UfCPs exposure in SHRs. UfCPs-mediated inflammatory responses were assessed from broncho-alveolar-lavage fluid (BALF).

RESULTS

Increased BP and heart rate (HR) by about 5% with a lag of 1-3 days were detected in UfCPs exposed SHRs. Inflammatory markers of BALF, lung (pulmonary) and blood (systemic) were not affected. However, mRNA expression of hemeoxygenase-1, endothelin-1, endothelin receptors A and B, tissue factor, and plasminogen activator inhibitor showed a significant induction (~2.5-fold; p < 0.05) with endothelin 1 being the maximally induced factor (6-fold; p < 0.05) on the third recovery day in the lungs of UfCPs exposed SHRs; while all of these factors - except hemeoxygenase-1 - were not affected in cardiac tissues. Strikingly, the UfCPs-mediated altered BP is paralleled by the induction of renin-angiotensin system in plasma.

CONCLUSION

Our finding shows that UfCPs exposure at levels which does not induce detectable pulmonary neutrophilic inflammation, triggers distinct effects in the lung and also at the systemic level in compromised SHRs. These effects are characterized by increased activity of plasma renin-angiotensin system and circulating white blood cells together with moderate increases in the BP, HR and decreases in heart rate variability. This systemic effect is associated with pulmonary, but not cardiac, mRNA induction of biomarkers reflective of oxidative stress; activation of vasoconstriction, stimulation of blood coagulation factors, and inhibition of fibrinolysis. Thus, UfCPs may cause cardiovascular and pulmonary impairment, in the absence of detectable pulmonary inflammation, in individuals suffering from preexisting cardiovascular diseases.

Environmental risk factors for heart disease

In this review, we discuss current evidence linking environmental pollutants to cardiovascular disease (CVD). Extensive evidence indicates that environmental factors contribute to CVD risk, incidence, and severity. Migrant studies show that changes in the environment could substantially alter CVD risk in a genetically stable population. Additionally, CVD risk is affected by changes in nutritional and lifestyle choices. Recent studies in the field of environmental cardiology suggest that environmental toxins also influence CVD. Exposure to tobacco smoke is paradigmatic of such environmental risk and is strongly and positively associated with increased cardiovascular morbidity and mortality. In animal models of exposure, tobacco smoke induces endothelial dysfunction and prothrombotic responses and exacerbates atherogenesis and myocardial ischemic injury. Similar mechanism may be engaged by other pollutants or food constituents. Several large population-based studies indicate that exposure to fine or ultrafine particulate air pollution increases CVD morbidity and mortality, and the plausibility of this association is supported by data from animal studies. Exposure to other chemicals such as polyaromatic hydrocarbons, aldehydes, and metals has also been reported to elevate CVD risk by affecting atherogenesis, thrombosis, or blood pressure regulation. Maternal exposure to drugs, toxins, and infection has been linked with cardiac birth defects and premature CVD in later life. Collectively, the data support the notion that chronic environmental stress is an important determinant of CVD risk. Further work is required to assess the magnitude of this risk fully and to delineate specific mechanisms by which environmental toxins affect CVD.