Fine particulate matter air pollution and atherosclerosis: Mechanistic insights

Association between residential air pollution exposure and cardiovascular risk factors in adults living in northern France

Air pollution is associated with elevated cardiovascular mortality and an increase in cardiovascular risk factors. However, the literature data on associations between air pollution and cardiovascular risk factors are contradictory. To explore the relationship between residential exposure to atmospheric pollutants and cardiovascular risk factors (lipid biomarker and blood pressure levels). We studied a sample of 2339 adult participants in the ELISABET study from the Dunkirk and Lille urban areas of France. The mean annual exposure to atmospheric pollutants (PM10, NO2 and SO2) at the home address was estimated via an air dispersion model. The associations were probed in multivariate linear regression models. The mean NO2 level was 26.05 μg/m3 in Lille and 19.96 µg/m3 in Dunkirk. The mean PM10 level was 27.02 μg/m3 in Lille and 26.53 μg/m3 in Dunkirk. We detected a significant association between exposure to air pollutants and the high-density lipoprotein (HDL) (which is a protective factor against cardiovascular diseases) level: for a 2 µg/m3 increment in PM10, the HDL level decreased by 1.72% (p = 0.0037). None of the associations with other lipid variables or with blood pressure were significant. We didn't find evidence significant associations for most of the risk factors but, long-term exposure of adults to moderate levels of ambient air pollution was associated with a decrement in HDL.

Air pollution, cardiorespiratory fitness and biomarkers of oxidative status and inflammation in the 4HAIE study

The aim of this study was to investigate the associations between cardiorespiratory fitness (CRF), long-term air pollution exposure and biochemical markers of oxidative status and inflammation. This is a cross-sectional investigation focusing on biochemical markers of oxidative status and inflammation. Participants were Caucasian (N = 1188; age 18-65 years) who lived for at least 5 years in a high air-polluted (Moravian-Silesian; MS) or low air-polluted (South Bohemia; SB) region of the Czech Republic. Healthy runners and inactive individuals were recruited. A multiple regression analysis was used to explain the relationship between multiple independent variables (CRF, trunk fat mass, sex, socioeconomic status, and region (MS region vs. SB region) and dependent variables (oxidative status, inflammation). CRF, trunk fat mass, age and sex significantly predicted almost all selected markers of oxidative status and inflammation (except GSSG, GSH/GSSG and BDNF). Participants living in the MS region presented significantly higher GPx (by 3.1%) and lower BDNF values (by 4.5%). All other investigated biochemical markers were not significantly influenced by region. We did not find meaningful interactions between long-term air-pollution exposure versus markers of oxidative status and inflammation. However, we showed various significant interactions with sex, age, CRF and body composition. The significant association of living in the high air polluted MS region with the BDNF level warrants further attention.

First assessment of atmospheric pollution by trace elements and particulate matter after a severe collapse of a tailings dam, Minas Gerais, Brazil: An insight into biomonitoring with Tillandsia usneoides and a public health dataset

In this study, samples of bromeliad Tillandsia usneoides (n = 70) were transplanted and exposed for 15 and 45 days in 35 outdoor residential areas in Brumadinho (Minas Gerais state, Brazil) after one of the most severe mining dam collapses in the world. Trace elements aluminum (Al), arsenic (As), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni) and zinc (Zn) were quantified by atomic absorption spectrometry. Scanning electron microscope generated surface images of T. usneoides fragments and particulate matter (PM2.5, PM10 and PM > 10). Aluminum, Fe and Mn stood out from the other elements reflecting the regional geological background. Median concentrations in mg kg-1 increased (p < 0.05) between 15 and 45 days for Cr (0.75), Cu (1.23), Fe (474) and Mn (38.1), while Hg (0.18) was higher at 15 days. The exposed-to-control ratio revealed that As and Hg increased 18.1 and 9.4-fold, respectively, not showing a pattern associated only with the most impacted sites. The PM analysis points to a possible influence of the prevailing west wind on the increase of total particles, PM2.5 and PM10 in transplant sites located to the east. Brazilian public health dataset revealed increase in cases of some cardiovascular and respiratory diseases/symptoms in Brumadinho in the year of the dam collapse (1.38 cases per 1000 inhabitants), while Belo Horizonte capital and its metropolitan region recorded 0.97 and 0.37 cases, respectively. Although many studies have been carried out to assess the consequences of the tailings dam failure, until now atmospheric pollution had not yet been evaluated. Furthermore, based on our exploratory analysis of human health dataset, epidemiological studies are required to verify possible risk factors associated with the increase in hospital admissions in the study area.

Chronic Occupational Exposure to Traffic Pollution Is Associated with Increased Carotid Intima-Media Thickness in Healthy Urban Traffic Control Police

Urban traffic officers in many low- and middle-income countries are exposed to high levels of traffic-related air pollutants (TRAP) while working vehicle control on heavily congested streets. The impact of chronic TRAP exposure on the cardiovascular health, including the carotid intima-media thickness (CIMT), of this outdoor occupational group remains unclear. This cross-sectional study compared the average mean and maximum CIMT measurements of two groups of relatively young, healthy traffic police (32 ± 7 years; 77% male) in Quito, Ecuador, who were without clinical evidence of serious cardiovascular or other disease. Previously published background data on PM10 (a TRAP surrogate) indicated that street levels of the pollutant were several orders of magnitude higher at the street intersections worked by traffic police compared to those working only in an office. Accordingly, officers permanently assigned to daily traffic control duties requiring them to stand 0-3 m from heavily trafficked street intersections were assigned to the high exposure group (n = 61). The control group (n = 54) consisted of officers from the same organization who were permanently assigned to office duties inside an administration building. Mean and maximum CIMT were measured with ultrasound. General linear models were used to compare the CIMT measurements of the high exposure and control groups, adjusting for covariates. The adjusted average mean and maximum CIMT measures of the high exposure group were increased by 11.5% and 10.3%, respectively, compared to the control group (p = 0.0001). These findings suggest that chronic occupational exposure to TRAP is associated with increased CIMT in traffic police. This is important since even small increases in arterial thickening over time may promote earlier progression to clinical disease and increased premature mortality risk.

Polycyclic aromatic hydrocarbons in urban particle matter exacerbate movement disorder after ischemic stroke via potentiation of neuroinflammation

BACKGROUND

A recent epidemiological study showed that air pollution is closely involved in the prognosis of ischemic stroke. We and others have reported that microglial activation in ischemic stroke plays an important role in neuronal damage. In this study, we investigated the effects of urban aerosol exposure on neuroinflammation and the prognosis of ischemic stroke using a mouse photothrombotic model.

RESULTS

When mice were intranasally exposed to CRM28, urban aerosols collected in Beijing, China, for 7 days, microglial activation was observed in the olfactory bulb and cerebral cortex. Mice exposed to CRM28 showed increased microglial activity and exacerbation of movement disorder after ischemic stroke induction. Administration of core particles stripped of attached chemicals from CRM28 by washing showed less microglial activation and suppression of movement disorder compared with CRM28-treated groups. CRM28 exposure did not affect the prognosis of ischemic stroke in null mice for aryl hydrocarbon receptor, a polycyclic aromatic hydrocarbon (PAH) receptor. Exposure to PM2.5 collected at Yokohama, Japan also exacerbated movement disorder after ischemic stroke.

CONCLUSION

Particle matter in the air is involved in neuroinflammation and aggravation of the prognosis of ischemic stroke; furthermore, PAHs in the particle matter could be responsible for the prognosis exacerbation.

Impact of air pollution on ischemic heart disease: Evidence, mechanisms, clinical perspectives

Ambient air pollution, and especially particulate matter (PM) air pollution <2.5 μm in diameter (PM_2.5), has clearly emerged as an important yet often overlooked risk factor for atherosclerosis and ischemic heart disease (IHD). In this review, we examine the available evidence demonstrating how acute and chronic PM_2.5 exposure clinically translates into a heightened coronary atherosclerotic burden and an increased risk of acute ischemic coronary events. Moreover, we provide insights into the pathophysiologic mechanisms underlying PM_2.5-mediated atherosclerosis, focusing on the specific biological mechanism through which PM_2.5 exerts its detrimental effects. Further, we discuss about the possible mechanisms that explain the recent findings reporting a strong association between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, increased PM_2.5 exposure, and morbidity and mortality from IHD. We also address the possible mitigation strategies that should be implemented to reduce the impact of PM_2.5 on cardiovascular morbidity and mortality, and underscoring the strong need of clinical trials demonstrating the efficacy of specific interventions (including both PM_2.5 reduction and/or specific drugs) in reducing the incidence of IHD. Finally, we introduce the emerging concept of the exposome, highlighting the close relationship between PM_2.5 and other environmental exposures (i.e.: traffic noise and climate change) in terms of common underlying pathophysiologic mechanisms and possible mitigation strategies.

Changes in the liver proteome in apoE knockout mice exposed to inhalation of silica nanoparticles indicate mitochondrial damage and impairment of ER stress responses associated with microvesicular steatosis

The adverse effects of air pollution on the cardiovascular system have been well documented. Nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for cardiovascular events. However, the influence of exposure to airborne particles on the development of NAFLD is less recognised. The aim of this study was to investigate the impact of silica nanoparticles (SiNPs) on the development of liver steatosis. We used molecular and proteomic SWATH-MS methods to investigate the changes in the liver proteome of apolipoprotein E-knockout mice (apoE^-/- mice) exposed to SiNPs for 4 months in a whole-body exposure chamber. Exposure to SiNPs evoked microvesicular liver steatosis in apoE^-/- mice. Quantitative liver proteomics showed significant downregulation of ribosomal proteins and endoplasmic reticulum proteins. Gene expression analysis revealed a reduced level of proteins related to endoplasmic reticulum stress. Treatment with SiNPs decreased mitochondrial membrane potential and increased the production of reactive oxygen species in cultured HepG2 cells. This is the first report that inhalation exposure to SiNPs induces microvesicular steatosis and significant changes in the liver proteome in vivo. Our results highlight the important role of silica and point to the ER stress response and mitochondrial dysfunction as potential mechanisms responsible for the increase in fatty liver by SiNPs.

Particulate arsenic trioxide induces higher DNA damage and reactive oxygen species than soluble arsenite in lung epithelial cells

Environmental arsenic exposure is associated with lung cancer. Arsenic is the first substance known to cause lung cancer by two distinct routes, ingestion and inhalation, in the forms of soluble arsenite and particulate arsenic trioxide, respectively. In comparison to significant progresses in research on mechanisms for lung carcinogenesis of arsenic ingestion, inhalation arsenic exposure route in particulate form and its lung carcinogenic mechanisms are relatively under-investigated. Fundamentally, it remains unclear whether particulate arsenic exposure is in a dissolved form and whether particulate exposure yields higher damage. Utilizing dynamic laser scattering, particulate arsenic trioxide exposure in cellular system was confirmed to be in particulate form instead of dissolved form. Using immunofluorescence, particulate arsenic trioxide was demonstrated to generate dramatically higher oxidative DNA damage and strand break, as well as significantly higher superoxide, in lung epithelial cell lines such as BEAS-2B, HSAEC1-KT, and SAE, comparing to soluble arsenite exposure at similar or lower concentration. This study demonstrated that particulate arsenic trioxide exposure yields higher damage in lung epithelial cells, and indicated that inhalation route of particulate arsenic exposure plays an important role in lung carcinogenesis.

Association of Short-Term Exposure to PM2.5 with Blood Lipids and the Modification Effects of Insulin Resistance: A Panel Study in Wuhan

Results of previous studies about the acute effects of fine particulate matter (PM2.5) on blood lipids were inconsistent. This study aimed to quantify the short-term effects of PM2.5 on blood lipids and estimate the modifying role of insulin resistance, reflected by the homeostasis model assessment of insulin resistance (HOMA-IR). From September 2019 to January 2020, the study recruited 70 healthy adults from Wuhan University for a total of eight repeated data collections. At each visit, three consecutive days were monitored for personal exposure to PM2.5, and then a physical examination was carried out on the fourth day. The linear mixed-effect models were operated to investigate the impact of PM2.5 over diverse exposure windows on blood lipids. With the median of the HOMA-IR 1.820 as the cut-off point, participants were assigned to two groups for the interaction analyses. We found the overall mean level (standard deviation, SD) of PM2.5 was 38.34 (18.33) μg/m3. Additionally, with a 10 μg/m3 rise in PM2.5, the corresponding largest responses in triglyceride (TG), total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), as well as high-density lipoprotein cholesterol (HDL-C), were −0.91% (95% confidence interval (CI): −1.63%, −0.18%), −0.33% (95% CI: −0.64%, −0.01%,), −0.94% (95% CI: −1.53%, −0.35%), and 0.67% (95% CI: 0.32%, 1.02%), respectively. The interaction analyses revealed that a significantly greater reduction in the four lipids corresponded to PM2.5 exposure when in the group with the lower HOMA-IR (<1.820). In conclusion, short-term PM2.5 exposure over specific time windows among healthy adults was associated with reduced TG, TC, as well as LDL-C levels, and elevated HDL-C. Additionally, the association of PM2.5−lipids may be modulated by insulin resistance.

The Role of Fine Particles (PM 2.5) in the Genesis of Atherosclerosis and Myocardial Damage: Emphasis on Clinical and Epidemiological Data, and Pathophysiological Mechanisms

Due to the fact that atherosclerotic cardiovascular diseases (CVDs) dominate in the structure of morbidity, disability and mortality of the population, the study of the risk factors for the development of atherosclerotic CVDs, as well as the study of the underlying pathogenetic mechanisms thereof, is the most important area of scientific research in modern medicine. Understanding these aspects will allow to improve the set of treatment and preventive measures and activities. One of the important risk factors for the development of atherosclerosis, which has been actively studied recently, is air pollution with fine particulate matter (PM 2.5). According to clinical and epidemiological data, the level of air pollution with PM 2.5 exceeds the normative indicators in most regions of the world and is associated with subclinical markers of atherosclerosis and mortality from atherosclerotic CVDs. The aim of this article is to systematize and discuss in detail the role of PM 2.5 in the development of atherosclerosis and myocardial damage.

Effects of Particulate Matter on Inflammation and Thrombosis: Past Evidence for Future Prevention

Ambient air pollution has become a common problem worldwide. Exposure to pollutant particles causes many health conditions, having a particular impact on pulmonary and cardiovascular disease. Increased understanding of the pathological processes related to these conditions may facilitate the prevention of the adverse impact of air pollution on our physical health. Evidence from in vitro, in vivo, and clinical studies has consistently shown that exposure to particulate matter could induce the inflammatory responses such as IL-6, TNF-α, IL-1β, as well as enhancing the oxidative stress. These result in vascular injury, adhesion molecule release, platelet activation, and thrombin generation, ultimately leading to a prothrombotic state. In this review, evidence on the effects of particulate matter on inflammation, oxidative stress, adhesion molecules, and coagulation pathways in enhancing the risk of thrombosis is comprehensively summarized and discussed. The currently available outcomes of interventional studies at a cellular level and clinical reports are also presented and discussed.

Sensitive inflammatory biomarkers of acute fine particulate matter exposure among healthy young adults: Findings from a randomized, double-blind crossover trial on air filtration

The short-term alteration of peripheral cytokines may be an early adverse health effect of PM_2.5 exposure and may be further associated with cardiovascular disease. We conducted a randomized, double-blind crossover trial using true or sham air filtration among 54 healthy college students in Beijing to investigate the potential benefits of short-term indoor air filtration and the adverse health effects of time-weighted personal PM_2.5 exposure through inflammatory cytokines. The participants randomly received true or sham air filtration intervention for a week, and the treatment was changed after a two-week washout period. Peripheral blood samples were collected after each intervention period to measure 38 inflammatory cytokines. A linear mixed-effects model was applied to estimate the impacts of air purification or a 10 μg/m³ PM_2.5 exposure increase on cytokines. Lag effects of PM_2.5 exposure were analyzed using single-day and moving average lag models. Air filtration reduced indoor and time-weighted average personal PM_2.5 concentrations by 69.0% (from 33.6 to 10.4 μg/m³) and 40.3% (from 40.6 to 24.3 μg/m³), respectively. We observed a significant association of PM_2.5 exposure with growth-regulated alpha protein (GRO-α) of -11.3% (95%CI: 17.0%, -5.4%). In the lag models, significant associations between personal PM_2.5 exposure and interleukin-1 receptor antagonist (IL-1Ra), monocyte chemotactic protein (MCP-1), and eotaxin were obtained at lag0, while associations with cytokines including vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), fibroblast growth factor-2 (FGF-2), granulocyte colony-stimulating factor (G-CSF), macrophage inflammatory protein-1β (MIP-1β), IL-4, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) were noted at relatively long lagged exposure windows (lag5-lag6). No significant alteration in cytokines was observed under true air filtration intervention. Our study indicates the effectiveness of air filtration on indoor PM_2.5 reduction. PM_2.5 exposure may decrease GRO-α levels and change different cytokine levels time-varyingly. Further study is still needed to explore the mechanisms of PM_2.5 exposure on the inflammatory response.

Acute differences in blood lipids and inflammatory biomarkers following controlled exposures to cookstove air pollution in the STOVES study

Household air pollution is a leading risk factor for morbidity and premature mortality. Numerous cookstoves have been developed to reduce household air pollution, but it is unclear whether such cookstoves meaningfully improve health. In a controlled exposure study with a crossover design, we assessed the effect of pollution emitted from multiple cookstoves on acute differences in blood lipids and inflammatory biomarkers. Participants (n = 48) were assigned to treatment sequences of exposure to air pollution emitted from five cookstoves and a filtered-air control. Blood lipids and inflammatory biomarkers were measured before and 0, 3, and 24 hours after treatments. Many of the measured outcomes had inconsistent results. However, compared to control, intercellular adhesion molecule-1 was higher 3 hours after all treatments, and C-reactive protein and serum amyloid-A were higher 24 hours after the highest treatment. Our results suggest that short-term exposure to cookstove air pollution can increase inflammatory biomarkers within 24 hours.

Air pollution and high-intensity interval exercise: Implications to anti-inflammatory balance, metabolome and cardiovascular responses

High-intensity interval exercise (HIIE) is an effective non-pharmacological tool for improving physiological responses related to health. When HIIE is performed in urban centers, however, the exerciser is exposed to traffic-related air pollution (TRAP), which is associated with metabolic, anti-inflammatory imbalance and cardiovascular diseases. This paradoxical combination has the potential for conflicting health effects. Thus, the aim of this study was to determine the effects of HIIE performed in TRAP exposure on serum cytokines, non-target metabolomics and cardiovascular parameters. Fifteen participants performed HIIE in a chamber capable to deliver filtered air (FA condition) or non-filtered air (TRAP condition) from a polluted site adjacent to the exposure chamber. Non-target blood serum metabolomics, blood serum cytokines and blood pressure analyses were collected in both FA and TRAP conditions at baseline, 10 min after exercise, and 1 h after exercise. The TRAP increased IL-6 concentration by 1.7 times 1 h after exercise (p < 0.01) and did not change the anti-inflammatory balance (IL-10/TNF-α ratio). In contrast, FA led to an increase in IL-10 and IL-10/TNF-α ratio (p < 0.01), by 2.1 and 2.3 times, respectively. The enrichment analysis showed incomplete fatty acid metabolism under the TRAP condition (p < 0.05) 10 min after exercise. There was also an overactivity of ketone body metabolism (p < 0.05) at 10 min and at 1 h after exercise with TRAP. Exercise-induced acute decrease in systolic blood pressure (SBP) was not observed at 10 min and impaired at 1 h after exercise (p < 0.05). These findings reveal that TRAP potentially attenuates health benefits often related to HIIE. For instance, the anti-inflammatory balance was impaired, accompanied by accumulation of metabolites related to energy supply and reduction to exercise-induced decrease in SBP.

Particulate matter causes telomere shortening and increase in cellular senescence markers in human lung epithelial cells

Exposure to particulate matter (PM) has been associated with DNA damage, but the relationships between PM, telomere length and cellular senescence remain unclear. This study aimed to investigate the effects and potential mechanisms of PM on telomere length and cellular senescence in human lung epithelial cells. Human lung epithelial A549 cells were exposed to PM for 24 h. Cell viability and cytotoxicity were measured by the WST-1 assay and the lactate dehydrogenase release, respectively. Cellular uptake of PM was observed using transmission electron microscopy. Telomere length was measured using qPCR and expressed as T/S ratio. Cell cycle progression was analyzed by flow cytometry. Expression of human telomerase reverse transcriptase (hTERT) and cell cycle regulators was measured using mRNA by qPCR and protein levels by Western blot. Cellular senescence was determined by the expression of senescence-associated β-galactosidase (SA-β-Gal) with fluorescent microscopy and flow cytometry. Exposed to PM at the concentration of 200 μg/ml decreased cell viability and increased LDH levels in culture medium. Remarkably increased uptake of PM, shortening of telomere length, induction of G0/G1 phase arrest, and increased expression of senescence hallmarks were observed after exposure to PM in A549 cells. PM exposure induced upregulation of p21 and downregulation of proliferating cell nuclear antigen (PCNA) and hTERT expression, but no significant change in p53 expression, in A549 cells. Overall, exposure to PM may downregulate hTERT and PCNA through p53-independent induction of p21 expression, leading to telomere shortening, G0/G1 arrest and the onset of cellular senescence in human lung epithelial cells.

Key Characteristics of Cardiovascular Toxicants

BACKGROUND

The concept of chemical agents having properties that confer potential hazard called key characteristics (KCs) was first developed to identify carcinogenic hazards. Identification of KCs of cardiovascular (CV) toxicants could facilitate the systematic assessment of CV hazards and understanding of assay and data gaps associated with current approaches.

OBJECTIVES

We sought to develop a consensus-based synthesis of scientific evidence on the KCs of chemical and nonchemical agents known to cause CV toxicity along with methods to measure them.

METHODS

An expert working group was convened to discuss mechanisms associated with CV toxicity.

RESULTS

The group identified 12 KCs of CV toxicants, defined as exogenous agents that adversely interfere with function of the CV system. The KCs were organized into those primarily affecting cardiac tissue (numbers 1-4 below), the vascular system (5-7), or both (8-12), as follows: 1) impairs regulation of cardiac excitability, 2) impairs cardiac contractility and relaxation, 3) induces cardiomyocyte injury and death, 4) induces proliferation of valve stroma, 5) impacts endothelial and vascular function, 6) alters hemostasis, 7) causes dyslipidemia, 8) impairs mitochondrial function, 9) modifies autonomic nervous system activity, 10) induces oxidative stress, 11) causes inflammation, and 12) alters hormone signaling.

DISCUSSION

These 12 KCs can be used to help identify pharmaceuticals and environmental pollutants as CV toxicants, as well as to better understand the mechanistic underpinnings of their toxicity. For example, evidence exists that fine particulate matter [PM ≤2.5μm in aerodynamic diameter (PM2.5)] air pollution, arsenic, anthracycline drugs, and other exogenous chemicals possess one or more of the described KCs. In conclusion, the KCs could be used to identify potential CV toxicants and to define a set of test methods to evaluate CV toxicity in a more comprehensive and standardized manner than current approaches. https://doi.org/10.1289/EHP9321.

Association of COVID-19 transmission with high levels of ambient pollutants: Initiation and impact of the inflammatory response on cardiopulmonary disease

Ambient air pollution contributes to 7 million premature deaths annually. Concurrently, the ongoing coronavirus disease 2019 (COVID-19) pandemic, complicated with S-protein mutations and other variants, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in over 2.5 million deaths globally. Chronic air pollution-mediated cardiopulmonary diseases have been associated with an increased incidence of hospitalization and mechanical ventilation following COVID-19 transmission. While the underlying mechanisms responsible for this association remain elusive, air pollutant-induced vascular oxidative stress and inflammatory responses have been implicated in amplifying COVID-19-mediated cytokine release and vascular thrombosis. In addition, prolonged exposure to certain types of particulate matter (PM2.5, d < 2.5 μm) has also been correlated with increased lung epithelial and vascular endothelial expression of the angiotensin-converting enzyme-2 (ACE2) receptors to which the SARS-CoV-2 spike glycoproteins (S) bind for fusion and internalization into host cells. Emerging literature has linked high rates of SARS-CoV-2 infection to regions with elevated levels of PM2.5, suggesting that COVID-19 lockdowns have been implicated in regional reductions in air pollutant-mediated cardiopulmonary effects. Taken together, an increased incidence of SARS-CoV-2-mediated cardiopulmonary diseases seems to overlap with highly polluted regions. To this end, we will review the redox-active components of air pollutants, the pathophysiology of SARS-CoV-2 transmission, and the key oxidative mechanisms and ACE2 overexpression underlying air pollution-exacerbated SARS-CoV-2 transmission.

PM2.5 promotes β cell damage by increasing inflammatory factors in mice with streptozotocin

Emerging evidence indicates that exposure to fine particulate matter contributes to the onset of diabetes. The present study aimed to investigate the mechanism of particulate matters (PM)_2.5 affecting glucose homeostasis in mice with type 1 diabetes mellitus. Male C57BL/6 mice were housed under filtered air (FA) or PM_2.5 for 12 weeks and then received intraperitoneal injection of streptozotocin (STZ; 40 mg/kg) or acetic buffer daily for 5 days. At 4 weeks after the last injection, fasting glucose was tested. In the plasma and liver, cholesterol levels were determined by cholesterol oxidase-peroxidase and triglyceride levels were determined by triglycerophosphate oxidase-peroxidase. Homeostasis model assessment of β cell function (Homa-β) was computed based on fasting insulin and glucose levels. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNFα) levels in plasma, visceral adipose tissues, RAW264.7 macrophages and MIN6 pancreatic β cells treated with PM_2.5 (0-50 µg/ml) were quantified via ELISA. Before STZ injection, fasting blood glucose (FBG) levels were similar between FA and PM_2.5 groups. After STZ injection, FBG levels were higher in mice pre-exposed to PM_2.5 compared with those pre-exposed to FA. When taking FBG levels ≥7 mmol/l as the criteria for impaired glucose level, its incidence was 53.3% and 77.8% in FA and PM_2.5 groups, respectively. Independent of STZ injection, IL-1β levels in the adipose tissue were upregulated in mice pre-exposed to PM_2.5 compared with FA. The addition of PM_2.5 stimulated IL-1β and TNFα production in macrophages and pancreatic β cells, and inhibited the secretion of insulin from MIN6 cells in a dose-dependent manner. In conclusion, pre-exposure of PM_2.5 impaired pancreatic β cells in mice upon STZ injection, partially via enhanced inflammation, and suppressed the secretion of insulin.

Environmental Pollution and Peripheral Artery Disease

Peripheral artery disease (PAD) of the lower limbs represents one of the most important clinical conditions among vascular disease and can negatively impact quality of life of affected patients, representing also an important socioeconomic burden. Several risk factors predispose to PAD and its complications. Nevertheless, the role of pollution in this context has not been fully evaluated and this article explored the most updated information on epidemiology and environmental pollution in order to hypothesize the possible contribution of air pollution in the onset of PAD. Pollution is an important problem for the global community and has harmful effects on human health and cardiovascular system, and, specifically, particulate matter 10 (PM₁₀) was found significantly associated with PAD.

MiR-939-5p suppresses PM2.5-induced endothelial injury via targeting HIF-1α in HAECs

Ambient air pollution is a leading cause of non-communicable disease in the world. PM_2.5 has the potential to change the miRNAs profiles, which in turn causes cardiovascular effects. Hypoxia-inducible factor (HIF)-1 plays a critical role in the development of atherosclerosis. Yet, the possible role of miR-939-5p/HIF-1α in PM_2.5-induced endothelial injury remains elusive. Therefore, the study aims to investigate the effects of miR-939-5p and HIF-1α on PM_2.5-triggered endothelial injury. The results from immunofluorescence, qRT-PCR, LSCM, and western blot assays demonstrated that PM_2.5 increased the levels of HIF-1α, inflammation and apoptosis in human aortic endothelial cells (HAECs). Yet, the inflammatory response and mitochondrial-mediated apoptosis pathway were effectively inhibited in HIF-1α knockdown HAECs lines. The expression of miR-939-5p was significantly down-regulated in HAECs after exposed to PM_2.5. The luciferase reporter, qRT-PCR and western blot results demonstrated that miR-939-5p could directly targeted HIF-1α. And the miR-939-5p overexpression restricted PM_2.5-triggered decreases in cell viability and increases in lactic dehydrogenase (LDH) activity, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and inflammation. In addition, miR-939-5p overexpression remarkably suppressed PM_2.5-triggered BcL-2/Bax ratio reduction and Cytochrome C, Cleaved Caspase-9 and Cleaved Caspase-3 expression increase, revealed that miR-939-5p hampered PM_2.5-induced endothelial apoptosis through mitochondrial-mediated apoptosis pathway. Our results demonstrated that PM_2.5 increased the expression of HIF-1α followed by a pro-inflammatory and apoptotic response in HAECs. The protective effect of miR-939-5p on PM_2.5-triggered endothelial cell injury by negatively regulating HIF-1α. miR-939-5p might present a new therapeutic target for PM_2.5 induced endothelial injury.

Ambient air pollution and hospital visits for peptic ulcer disease in China: A three-year analysis

BACKGROUND

Peptic ulcer disease (PUD) continued to be a source of significant morbidity and mortality worldwide. Recently, it has been reported that exposure to air pollution is a potential risk factor for PUD, but evidence on the association still remains inconsistent.

METHODS

We performed an ecological study to examine the association between short-term exposure to air pollution and daily hospital visits for PUD in Yinzhou, China from January 1st, 2017 to December 31st, 2019. Distributed lag nonlinear models were used to estimate the nonlinear and lag-response effects of air pollutants. Subgroup analyses stratified by sex, age and season were conducted to examine the effect modifications.

RESULTS

Overall, we found that short-term exposure to air pollution including SO₂, NO₂, CO, O₃ and PM_2.5 was significantly associated with hospital visits for PUD among all subjects. The lag-response effects of SO₂, NO₂ and O₃ varied at different concentrations and lag days. The cumulative risk ratios of CO and PM_2.5 showed nearly linear adverse effects and increased to maxima of 2.68 (95% CI: 1.49-4.78) and 2.40 (95% CI: 1.36-4.24) with their ranges from the references to the maximum concentrations, respectively. Moreover, the cumulative risks of particulate matters on hospital visits for PUD increased significantly in cold seasons, but not in warm seasons.

CONCLUSIONS

Our findings could provide growing evidence regarding the adverse health effects of air pollution on PUD, thereby strengthening the hypothesis that air pollutants have harmful impacts on digestive system.

Association of air pollution and greenness with carotid plaque: A prospective cohort study in China

Previous studies indicated that exposure to air pollution was associated with the progress of atherosclerosis, but evidence is very limited in China and even in the world. This study aims to assess the associations of long-term exposures to air pollution and greenness with the occurrence of carotid plaque. Participants of this cohort study were urban residents and office workers who visited Hebei General Hospital for routine physical examination annually from September 2016 through to December 2018. Eligible participants were people diagnosed the absence of carotid plaque clinically at their first hospital visit and were followed up at their second or third hospital visit. Exposure to particulate matter with aerodynamic diameter less than 2.5 μm (PM2.5), nitrogen dioxide (NO2) and ozone (O3) were estimated using an inverse distance weighted (IDW) method. The level of greenness was assessed using the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI). The associations were evaluated using Cox proportional hazards regression models. Among 4,137 participants, 575 showed the occurrence of carotid plaque during the follow-up period. After controlling for potential confounders, the hazard ratios (HRs) and 95% confidence intervals (95%CIs) of carotid plaque associated with per interquartile range (IQR) increase in PM2.5, NO2, and O3 were 1.78 (1.55, 2.03), 1.32 (1.14, 1.53) and 1.99 (1.71, 2.31), respectively. Increased EVI and NDVI were significantly associated with lower risk of carotid plaque [HR (and 95%CI): 0.84 (0.77, 0.93) and 0.87 (0.80, 0.94)]. PM2.5 significantly mediated 80.47% or 93.00% of the estimated association between EVI or NDVI and carotid plaque. In light of the significant associations between air pollution, greenness and carotid plaque in this study, continued efforts are needed to curb air pollution and plan more green space considering their effects on vascular disease.

The association between ambient air pollution and blood lipids: A longitudinal study in Shijiazhuang, China

BACKGROUND

Few studies have explored the associations between ambient air pollution and blood lipid levels. This study aimed to fill this knowledge gap based on a routine health examination cohort in Shijiazhuang, China.

METHODS

We included 7063 participants who took the routine health examination for 2-3 times at Hebei General Hospital from January 2016 to December 2018. Individual serum levels of cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were measured. Their three-month average exposure to air pollution prior to the routine health examinations was estimated using inverse distance weighted method. We used linear mixed-effects regression models to examine the associations between air pollution and levels of blood lipids while controlling for age, gender, body mass index (BMI), smoking, alcohol drinking, temperature, humidity, with a random effect for each individual.

RESULTS

Particles with diameters ≤2.5 μm and ≤10 μm (PM_2.5 and PM₁₀), nitrogen dioxide (NO₂), sulfur dioxide (SO₂) and ozone (O₃) were all positively associated with TC, TG, and LDL-C and negatively associated with HDL-C, in single pollutant models. Each 10 μg/m³ increment of 3-month average PM_2.5 was associated with 0.65% [95% confidence interval (CI): 0.03%-1.28%], 0.56% (95%CI: 0.33%-0.79%) and 0.63% (95%CI: 0.35%-0.91%) increment in TG, TC, and LDL-C, and 0.91% (95%CI: 0.68%-1.13%) decrease in HDL-C. In two-pollutant models, the effects of gaseous pollutants on blood lipids were weakened, while those of PMs were strengthened. Stronger associations were presented in the elderly (≥60 years) and overweight/obese (BMI ≥ 24) participants.

CONCLUSIONS

Ambient air pollution had significantly adverse effects on blood lipid levels, especially in overweight/obese and elderly individuals.

CAPSULE

Significant associations between increased air pollution and worse blood lipid levels were found, especially in overweight/obese and elderly individuals.

Regular running in an air-polluted environment: physiological and anthropometric protocol for a prospective cohort study (Healthy Aging in Industrial Environment Study - Program 4)

INTRODUCTION

Ambient air pollution is a global environmental problem, which causes adverse health effects and premature deaths worldwide. Although regular exercise and physical activity have evident health benefits, the influence of long-term air pollution exposure during regular outdoor running has not been definitively clarified.

METHODS AND ANALYSIS

This study protocol describes the physiological and anthropometric perspectives of the 'Healthy Aging in Industrial Environment' Study - Programme 4 (4HAIE). The 4HAIE research project is intended to be a single-centre, prospective, longitudinal and multidisciplinary cohort study. The presented study protocol describes the cross-sectional measurements and analyses. Overall, 1500 adult participants (age 18-65 years), runners and inactive individuals, living in a high or low air-polluted area of the Czech Republic will be recruited. We will measure and analyse biomarkers of oxidative stress and inflammation in the blood, exercise capacity (graded exercise test and spiroergometry), blood pressure, lung function (spirometry), cardiac autonomic regulation and anthropometry (body composition).

ETHICS AND DISSEMINATION

The 4HAIE study protocol has already been approved by the Ethics Committee of the University of Ostrava (3/2018). A detailed participant information sheet will be provided to each individual prior to obtaining their written informed consent. The study poses little to no risk to participants. The findings of this study will be disseminated at regional and international conferences, in peer-reviewed journals and via social and broadcast media.

The critical role of endothelial function in fine particulate matter-induced atherosclerosis

Ambient and indoor air pollution contributes annually to approximately seven million premature deaths. Air pollution is a complex mixture of gaseous and particulate materials. In particular, fine particulate matter (PM2.5) plays a major mortality risk factor particularly on cardiovascular diseases through mechanisms of atherosclerosis, thrombosis and inflammation. A review on the PM2.5-induced atherosclerosis is needed to better understand the involved mechanisms. In this review, we summarized epidemiology and animal studies of PM2.5-induced atherosclerosis. Vascular endothelial injury is a critical early predictor of atherosclerosis. The evidence of mechanisms of PM2.5-induced atherosclerosis supports effects on vascular function. Thus, we summarized the main mechanisms of PM2.5-triggered vascular endothelial injury, which mainly involved three aspects, including vascular endothelial permeability, vasomotor function and vascular reparative capacity. Then we reviewed the relationship between PM2.5-induced endothelial injury and atherosclerosis. PM2.5-induced endothelial injury associated with inflammation, pro-coagulation and lipid deposition. Although the evidence of PM2.5-induced atherosclerosis is undergoing continual refinement, the mechanisms of PM2.5-triggered atherosclerosis are still limited, especially indoor PM2.5. Subsequent efforts of researchers are needed to improve the understanding of PM2.5 and atherosclerosis. Preventing or avoiding PM2.5-induced endothelial damage may greatly reduce the occurrence and development of atherosclerosis.

Comparison of quantitation methods in proteomics to define relevant toxicological information on AhR activation of HepG2 cells by BaP

The application of quantitative proteomics provides a new and promising tool for standardized toxicological research. However, choosing a suitable quantitative method still puzzles many researchers because the optimal method needs to be determined. In this study, we investigated the advantages and limitations of two of the most commonly used global quantitative proteomics methods, namely label-free quantitation (LFQ) and tandem mass tags (TMT). As a case study, we exposed hepatocytes (HepG2) to the environmental contaminant benzo[a]pyrene (BaP) using a concentration of 2 μM. Our results revealed that both methods yield a similar proteome coverage, in which for LFQ a wider range of fold changes was observed but with less significant p-values compared to TMT. We detected 37 and 47 significantly enriched pathways by LFQ and TMT, respectively, with 17 overlapping pathways. To define the minimally required effort in proteomics as a benchmark, we artificially reduced the LFQ, and TMT data sets stepwise and compared the pathway enrichment. Thereby, we found that fewer proteins are necessary for detecting significant enrichment of pathways in TMT compared to LFQ, which might be explained by the higher reproducibility of the TMT data that was observed. In summary, we showed that the TMT approach is the preferable one when investigating toxicological questions because it offers a high reproducibility and sufficient proteome coverage in a comparably short time.

Effects of ambient particulate matter on vascular tissue: a review

Fine and ultra-fine particulate matter (PM) are major constituents of urban air pollution and recognized risk factors for cardiovascular diseases. This review examined the effects of PM exposure on vascular tissue. Specific mechanisms by which PM affects the vasculature include inflammation, oxidative stress, actions on vascular tone and vasomotor responses, as well as atherosclerotic plaque formation. Further, there appears to be a greater PM exposure effect on susceptible individuals with pre-existing cardiovascular conditions.

Effect of Urban Particulate Matter on Vocal Fold Fibrosis through the MAPK/NF-κB Signaling Pathway

Particulate matter (PM) is an environmental exposure factor that adversely affects human health. PM is a risk factor for various diseases. However, the mechanism by which PM affects the vocal folds (VF) has not yet been evaluated. Thus, we investigated the cytotoxic effects of PM on human vocal fold fibroblasts (hVFF) and the underlying signaling pathways. hVFF were isolated from human VF. The effect of PM on hVFF, and the underlying mechanism, were analyzed using Western blot, quantitative real-time polymerase chain reaction, and flow cytometry. In addition, a histological evaluation was performed in animal experiments. Cell proliferation decreased after the PM treatment. PM increased the expression of interleukin (IL)-6 and IL-1β. The generation of reactive oxygen species (ROS) in PM-treated hVFF and subsequent activation of the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) pathways were confirmed. Furthermore, PM increased the expression of fibrosis-related markers and induced the accumulation of collagen in the extracellular matrix. As a result, PM exposure significantly enhances the inflammatory response on VF through the ROS-mediated activation of the MAPK and NF-κB signaling pathways. In addition, PM promotes differentiation into myofibroblasts and induces fibrosis. These results suggest that PM triggers an inflammatory reaction through ROS production and causes VF fibrosis.

Fine particulate matter exposure and renal function: A population-based study among pregnant women in China

BACKGROUND

Fine particulate matter (PM_2.5) is the most serious environmental threat worldwide. The nephrotoxicity of PM_2.5 has been demonstrated in older adults, but no study has addressed the impacts of PM_2.5 exposure on renal function in pregnant women, who are recognized to be vulnerable and susceptible to PM_2.5 exposure.

OBJECTIVE

To evaluate whether exposures to PM_2.5 total mass and its chemical constituents were associated with reduced renal function among pregnant women in China.

METHODS

We measured serum concentrations of urea nitrogen (UN), uric acid (UA) and creatinine for 10,052 pregnant women in Shanghai, China. Exposures to PM_2.5 total mass and its 5 key chemical constituents during the whole pregnancy and each trimester of pregnancy was represented by satellite-based models.

RESULTS

Exposures to PM_2.5 total mass and its chemical constituents of organic matter (OM), black carbon (BC), nitrate (NO₃^-) and ammonium (NH₄⁺) were positively associated with serum levels of UN and UA, and negatively associated with estimated glomerular filtration rate (eGFR). An interquartile rang (IQR) increase in PM_2.5 total mass, OM, BC, NO₃^- and NH₄⁺ exposure in third trimester was associated with 1.33 (β = -1.33, 95% CI, -1.79, -0.87), 1.67 (β = -1.67, 95% CI, -2.26, -1.07), 1.29 (β = -1.29, 95% CI,-1.89, -0.70), 1.16 (β = -1.16, 95% CI,-1.66, -0.65) and 0.76 (β = -0.76, 95% CI, -1.08, -0.44) mL/min/1.73 m² decrease in eGFR, respectively.

CONCLUSION

We concluded that exposures to PM_2.5 during pregnancy were associated with decreased renal function among pregnant women.

Targeting glutathione with the triterpenoid CDDO-Im protects against benzo-a-pyrene-1,6-quinone-induced cytotoxicity in endothelial cells

Epidemiological studies have exhibited a strong correlation between exposure to air pollution and deaths due to vascular diseases such as atherosclerosis. Benzo-a-pyrene-1,6-quinone (BP-1,6-Q) is one of the components of air pollution_. This study was to examine the role of GSH in BP-1,6-Q mediated cytotoxicity in human EA.hy96 endothelial cells and demonstrated that induction of cellular glutathione by a potent triterpenoid, CDDO-Im (1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole), protects cells against BP-1,6-Q induced protein and lipid damage. Incubation of EA.hy926 endothelial cells with BP-1,6-Q caused a significant increase in dose-dependent cytotoxicity as measured by LDH release assay and both apoptotic and necrotic cell deaths as measured by flow cytometric analysis. Incubation of EA.hy926 endothelial cells with BP-1,6-Q also caused a significant decrease in cellular GSH levels. The diminishment of cellular GSH by buthionine sulfoximine (BSO) potentiated BP-1,6-Q-induced toxicity significantly suggesting a critical involvement of GSH in BP-1,6-Q induced cellular toxicity. GSH-induction by CDDO-Im significantly protects cells against BP-1,6-Q induced protein and lipid damage as measured by protein carbonyl (PC) assay and thiobarbituric acid reactive substances (TBARS) assay, respectively. However, the co-treatment of cells with CDDO-Im and BSO reversed the cytoprotective effect of CDDO-Im on BP-1,6-Q-mediated lipid peroxidation and protein oxidation. These results suggest that induction of GSH by CDDO-Im might be the important cellular defense against BP-1,6-Q induced protein and lipid damage. These findings would contribute to better understand the action of BP-1,6-Q and may help to develop novel therapies to protect against BP-1,6-Q-induced atherogenesis.

Air pollutants and subsequent risk of chronic kidney disease and end-stage renal disease: A population-based cohort study

Air pollutants have been reported to be a possible risk factor of chronic kidney disease (CKD). However, epidemiologic results regarding acidic gases and CKD have yet to be elucidated. We linked the Taiwan Air Quality Monitoring Database (TAQMD) to the Longitudinal Health Insurance Database. An observational cohort of 161,970 Taiwan citizens who had not been diagnosed with CKD was formed. The concentrations of air pollutant were classified into four levels based on quartile. Multivariable and univariable Cox proportional hazard regression models were used to assess the risk of developing CKD and end-stage renal disease (ESRD). Compared with Q1-level SO2, exposure to the Q4 level was at a 1.46-fold risk of developing CKD (95% confidence interval [CI] = 1.28-1.65) and 1.32-fold risk of ESRD (95% CI = 1.03-1.70). Compared with Q1-level NOx, exposure to the Q4 level was at a 1.39-fold higher risk of developing CKD (95% CI = 1.22-1.58) and 1.70-fold risk of ESRD (95% CI = 1.33-2.18). Compared with Q1-level NO, exposure to the Q4 level was at a 1.48-fold risk of CKD (95% CI = 1.30-1.68) and 1.54-fold risk of ESRD (95% CI = 1.20-1.98). Compared with Q1-level particles <2.5 μm (PM2.5), exposure to the Q4 level were at a 1.74-fold risk of CKD (95% CI = 1.53-1.98) and 1.69-fold risk of ESRD (95% CI = 1.32-2.16). Exposure to particulate and acidic gas air pollution was observed to be associated with an increased risk of CKD and ESRD.

The Effects of Social, Personal, and Behavioral Risk Factors and PM2.5 on Cardio-Metabolic Disparities in a Cohort of Community Health Center Patients

(1) Background: Cardio-metabolic diseases (CMD), including cardiovascular disease, stroke, and diabetes, have numerous common individual and environmental risk factors. Yet, few studies to date have considered how these multiple risk factors together affect CMD disparities between Blacks and Whites. (2) Methods: We linked daily fine particulate matter (PM2.5) measures with survey responses of participants in the Southern Community Cohort Study (SCCS). Generalized linear mixed modeling (GLMM) was used to estimate the relationship between CMD risk and social-demographic characteristics, behavioral and personal risk factors, and exposure levels of PM2.5. (3) Results: The study resulted in four key findings: (1) PM2.5 concentration level was significantly associated with reported CMD, with risk rising by 2.6% for each µg/m3 increase in PM2.5; (2) race did not predict CMD risk when clinical, lifestyle, and environmental risk factors were accounted for; (3) a significant variation of CMD risk was found among participants across states; and (4) multiple personal, clinical, and social-demographic and environmental risk factors played a role in predicting CMD occurrence. (4) Conclusions: Disparities in CMD risk among low social status populations reflect the complex interactions of exposures and cumulative risks for CMD contributed by different personal and environmental factors from natural, built, and social environments.

Effects of coal-fired PM2.5 on the expression levels of atherosclerosis-related proteins and the phosphorylation level of MAPK in ApoE-/- mice

Background

Air pollution increases the morbidity and mortality of cardiovascular disease (CVD). Atherosclerosis (AS) is the pathological basis of most CVD, and the progression of atherosclerosis and the increase of fragile plaque rupture are the mechanism basis of the relationship between atmospheric particulate pollution and CVD. The aim of the present study was to investigate the effects of coal-fired fine particulate matter (PM_2.5) on the expression levels of atherosclerosis-related proteins (von Willebrand factor (vWF), Endothelin-1 (ET-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin, and to explore the role and mechanism of the progression of atherosclerosis induced by coal-fired PM_2.5 via the mitogen-activated protein kinase (MAPK) signaling pathways.

Methods

Different concentrations of PM_2.5 were given to apolipoprotein-E knockout (ApoE^−/−) mice via intratracheal instillation for 8 weeks. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of vWF, ET-1 in serum of mice. Immunohistochemistry was used to observe the expression and distribution of ICAM-1 and E-selectin in the aorta of mice. Western blot was used to investigate the phosphoylation of proteins relevant to MAPK signaling pathways.

Results

Coal-fired PM_2.5 exacerbated atherosclerosis induced by a high-fat diet. Fibrous cap formation, foam cells accumulation, and atherosclerotic lesions were observed in the aortas of PM_2.5-treated mice. Coal-fired PM_2.5 increased the protein levels of ET-1, ICAM-1, and E-selectin, but there was no significant difference in the vWF levels between the PM_2.5-treatment mice and the HFD control mice. Coal-fired PM_2.5 promoted the phosphorylation of p38, c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase (ERK) in aortic tissues of mice.

Conclusion

Coal-derived PM_2.5 exacerbated the formation of atherosclerosis in mice, increased the expression levels of atherosclerosis-related proteins in mice serum, and promoted the phosphorylation of proteins relevant to MAPK signaling pathway. Thus, MAPK signaling pathway may play a role in the atherosclerosis pathogenesis induced by Coal-derived PM_2.5.

Validation of PM2.5 model particle through physicochemical evaluation and atherosclerotic plaque formation in ApoE-/- mice

PM_2.5 particles are regarded as prominent risk factors that contribute to the development of atherosclerosis. However, the composition of PM_2.5 is rather complicated. This study aimed to provide a model particle that simulates the behavior of actual PM_2.5, for subsequent use in exploring mechanisms and major complications arising from PM_2.5. To establish model particles of PM_2.5, a series of monodisperse SiO₂ microspheres with different average grain diameters were mixed according to the size distribution of actual PM_2.5. The organic carbon (OC) was removed from PM_2.5 and coated onto the SiO₂ model particle, to formulate simulant PM_2.5. Results showed that the size distribution of the model particle was highly approximate to that of the PM_2.5 core. The polycyclic aromatic hydrocarbon (PAHs) composition profile of the simulated PM_2.5 were approximate to PM_2.5, and loading efficiency was approximately 80%-120%. Furthermore, compared to the control, SiO₂-only model particle had negligible cytotoxicity on cell viability and oxidative stress of HUVECs, and marginal effect on the lipid metabolism and atherosclerotic plaque formation in ApoE^-/- mice. In contrast, simulated PM_2.5 exhibited similar cytotoxic and detrimental effects on lipid metabolism and atherosclerotic plaque formation with actual PM_2.5. Traffic-related PM_2.5 had negative effects on endothelial function and led to the formation of atherosclerosis via oxidative stress. The simulated PM_2.5 simulated the outcomes of actual PM_2.5 exposure. Here, we show that SiO₂ particle model cores coated with OC could significantly assist in the evaluation of the effects of specific organic compositions bound on PM_2.5, specifically in the context of environmental health and safety.

Contribution of Satellite-Derived Aerosol Optical Depth PM2.5 Bayesian Concentration Surfaces to Respiratory-Cardiovascular Chronic Disease Hospitalizations in Baltimore, Maryland

The fine particulate matter baseline (PMB), which includes PM_2.5 monitor readings fused with Community Multiscale Air Quality (CMAQ) model predictions, using the Hierarchical Bayesian Model (HBM), is less accurate in rural areas without monitors. To address this issue, an upgraded HBM was used to form four experimental aerosol optical depth (AOD)-PM_2.5 concentration surfaces. A case-crossover design and conditional logistic regression evaluated the contribution of the AOD-PM_2.5 surfaces and PMB to four respiratory-cardiovascular hospital events in all 99 12 km² CMAQ grids, and in grids with and without ambient air monitors. For all four health outcomes, only two AOD-PM_2.5 surfaces, one not kriged (PMC) and the other kriged (PMCK), had significantly higher Odds Ratios (ORs) on lag days 0, 1, and 01 than PMB in all grids, and in grids without monitors. In grids with monitors, emergency department (ED) asthma PMCK on lag days 0, 1 and 01 and inpatient (IP) heart failure (HF) PMCK ORs on lag days 01 were significantly higher than PMB ORs. Warm season ORs were significantly higher than cold season ORs. Independent confirmation of these results should include AOD-PM_2.5 concentration surfaces with greater temporal-spatial resolution, now easily available from geostationary satellites, such as GOES-16 and GOES-17.

Biomarkers of exposure, effect, and susceptibility in occupational exposure to traffic-related air pollution: A review

There is a well-recognized association between environmental air pollution exposure and several human diseases. However, the relationship between diseases related to occupational air pollution exposure on roads and high levels of traffic-related air pollutants (TRAPs) is less substantiated. Biomarkers are essential tools in environmental and occupational toxicology, and studies on new biomarkers are increasingly relevant due to the need to determine early biomarkers to be assessed in exposure conditions. This review aimed to investigate the main advances in the biomonitoring of subjects occupationally exposed to air pollution, as well as to summarize the biomarkers of exposure, effect, and susceptibility. Furthermore, we discuss how biomarkers could be used to complement the current application of methods used to assess occupational exposures to xenobiotics present in air pollution. The databases used in the preparation of this review were PubMed, Scopus, and Science Direct. Considering the significant deleterious effects on health associated with chronic occupational exposure to xenobiotics, this topic deserves attention. As it is difficult to avoid occupational exposure to TRAPs, biomonitoring should be applied as a strategy to reduce the toxic effects of workplace exposure.

Increased risk of carotid atherosclerosis for long-term exposure to indoor coal-burning pollution in rural area, Hebei Province, China

Smoky coal burning is a predominant manner for heating and cooking in most rural areas, China. Air pollution is associated with the risk of atherosclerosis, however, the link between indoor air pollution induced by smoky coal burning and atherosclerosis is not very clear. Therefore, we designed a cross-sectional study to evaluate the association of long-term exposure to smoky coal burning pollutants with the risk of atherosclerosis. 426 and 326 participants were recruited from Nangong, China and assigned as the coal exposure and control group according to their heating and cooking way, respectively. The indoor air quality (PM2.5, CO, SO₂) was monitored. The association between coal burning exposure and the prevalence of atherosclerosis was evaluated by unconditional logistic regression analysis, adjusted for confounding factors. The inflammatory cytokines mRNAs (IL-8, SAA1, TNF-α, CRP) expression in whole blood were examined by qPCR. People in the coal exposure group had a higher risk of carotid atherosclerosis compared with the control (risk ratio [RR], 1.434; 95% confidence interval [95%CI], 1.063 to 1.934; P = 0.018). The association was stronger in smokers, drinkers and younger (<45 years old) individuals. The elevation of IL-8 (0.24, 95%CI, 0.06-0.58; P < 0.05), CRP (0.37, 95%CI, 0.05-0.70; P < 0.05), TNF-α (0.41, 95%CI, 0.14-0.67; P < 0.01) mRNAs expression in whole blood were positively related to coal exposure. Our results suggested long-term exposure to smoky coal burning emissions could increase the risk of carotid atherosclerosis. The potential mechanism might relate that coal burning emissions exposure induced inflammatory cytokines elevation which had adverse effects on atherosclerotic plaque, and then promoted the development of atherosclerosis.

Resveratrol alleviates chronic "real-world" ambient particulate matter-induced lung inflammation and fibrosis by inhibiting NLRP3 inflammasome activation in mice

BACKGROUND

Inhalation of fine particulate matter (PM_2.5) induces the occurrence of lung inflammation and fibrosis, but its molecular mechanism remains unclear. Resveratrol (RES) is known to have anti-inflammatory properties in many pulmonary diseases. Here, we aimed to investigate the effect of long-term "real-world" ambient PM exposure on lung inflammation and fibrosis and further explore the protective effect and mechanism of RES.

METHODS AND RESULTS

RES (50 and 100 mg/kg.bw) was administered to C57BL/6J mice that were exposed to ambient PM for 5 months. The control group breathed filtered air without RES, and the PM group was exposed to PM without RES. The inflammatory cytokine levels in bronchoalveolar lavage fluid (BALF) and lung fibrosis were evaluated by enzyme-linked immune sorbent assay (ELISA) kits and Masson's trichrome staining. The real-time PCR and Western blot analysis were used to determine the signal pathway. In vivo, PM exposure markedly elevated the levels of inflammatory cytokines and TGF-β1 in BALF, induced lung fibrosis. Meanwhile, PM exposure triggered autophagy process and activated the nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome in lung. Also, RES treatment abolished PM-induced lung inflammation and fibrosis, and inhibited autophagic process and NLRP3 inflammasome activation. In vitro, PM_2.5-induced cytotoxicity in BEAS-2B cells dose-dependently. Besides, RES alleviated PM_2.5-induced cytotoxicity, inhibited autophagic process and NLRP3 inflammasome activity and decreased IL-1β production in BEAS-2B cells.

CONCLUSION

Long-term PM exposure induced lung inflammation and fibrosis, and RES intervention alleviated these adverse effects via inhibiting autophagy-related NLRP3 inflammasome activation.

Glucose Homeostasis following Diesel Exhaust Particulate Matter Exposure in a Lung Epithelial Cell-Specific IKK2-Deficient Mouse Model

BACKGROUND

Pulmonary inflammation is believed to be central to the pathogenesis due to exposure to fine particulate matter with aerodynamic diameter [Formula: see text] ([Formula: see text]). This central role, however, has not yet been systemically examined.

OBJECTIVE

In the present study, we exploited a lung epithelial cell-specific inhibitor [Formula: see text] kinase 2 (IKK2) knockout mouse model to determine the role of pulmonary inflammation in the pathophysiology due to exposure to diesel exhaust particulate matter (DEP).

METHODS

[Formula: see text] (lung epithelial cell-specific IKK2 knockout, KO) and [Formula: see text] (wild-type, tgWT) mice were intratracheally instilled with either vehicle or DEP for 4 months, and their inflammatory response and glucose homeostasis were then assessed.

RESULTS

In comparison with tgWT mice, lung epithelial cell-specific IKK2-deficient mice had fewer DEP exposure-induced bronchoalveolar lavage fluid immune cells and proinflammatory cytokines as well as fewer DEP exposure-induced circulating proinflammatory cytokines. Glucose and insulin tolerance tests revealed that lung epithelial cell-specific IKK2 deficiency resulted in markedly less DEP exposure-induced insulin resistance and greater glucose tolerance. Akt phosphorylation analyses of insulin-responsive tissues showed that DEP exposure primarily targeted hepatic insulin sensitivity. Lung epithelial cell-specific IKK2-deficient mice had significantly lower hepatic insulin resistance than tgWT mice had. Furthermore, this difference in insulin resistance was accompanied by consistent differences in hepatic insulin receptor substrate 1 serine phosphorylation and inflammatory marker expression.

DISCUSSION

Our findings suggest that in a tissue-specific knockout mouse model, an IKK2-dependent pulmonary inflammatory response was essential for the development of abnormal glucose homeostasis due to exposure to DEP. https://doi.org/10.1289/EHP4591.

Cytokine Circuits in Cardiovascular Disease

Arterial inflammation is a hallmark of atherosclerosis, and appropriate management of this inflammation represents a major unmet therapeutic need for cardiovascular disease patients. Here, we review the diverse contributions of immune cells to atherosclerosis, the mechanisms of immune cell activation in this context, and the cytokine circuits that underlie disease progression. We discuss the recent application of these insights in the form of immunotherapy to treat cardiovascular disease and highlight how studies on the cardiovascular co-morbidity that arises in autoimmunity might reveal additional roles for cytokines in atherosclerosis. Currently, data point to interleukin-1β (IL-1β), tumor necrosis factor (TNF), and IL-17 as cytokines that, at least in some settings, are effective targets to reduce cardiovascular disease progression.

PM2.5 exposure induces systemic inflammation and oxidative stress in an intracranial atherosclerosis rat model

OBJECTIVES

Exposure to airborne particle (PM_2.5 ) is a risk factor for intracranial atherosclerosis (ICA). Because of the established role of systemic inflammation and oxidative stress by PM_2.5 , we determined whether these processes account for PM_2.5 -mediated ICA, and also whether omega-3 fatty acid (O3FA) dietary supplementation could attenuate them.

METHODS

Adult Sprague-Dawley rats were exposed to filtered air (FA) or PM_2.5 and fed either a normal chow diet (NCD) or a high-cholesterol diet (HCD), administered with or without O3FA (5 mg/kg/day by gavage) for 12 weeks. The lumen and thickness of the middle cerebral artery (MCA) were assessed. Serum tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin-1β (IL-1β), and interferon gamma (IFN-γ) were detected by ELISA. Reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) activity, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX) activity, mRNA levels of Nrf2, HO-1, NQO-1, and protein level of NOX subunit gp91 were quantified to determine the oxidative profile of brain vessels.

RESULTS

PM_2.5 increased (P < .05) ICA, especially in the HCD group; elevated serum TNF-α, IL-6, IL-1β, and IFN-γ; increased cerebrovascular ROS, MDA, NOX activity, and gp91 protein levels; and decreased cerebrovascular SOD activity. Nrf2, HO-1, and NQO-1 mRNA levels were upregulated (P < .05) by PM_2.5 exposure, especially in the HCD group. O3FA attenuated (P < .05) PM_2.5 -induced systemic inflammation, vascular oxidative injury, and ICA.

CONCLUSIONS

PM_2.5 exposure induced systemic inflammation, cerebrovascular oxidative injury, and ICA in rats with HCD. O3FA prevented ICA development, and may therefore exert a protective effect against the atherogenic potential of PM_2.5 .

Haze Influencing Factors: A Data Envelopment Analysis Approach

This paper investigates the meteorological factors and human activities that influence PM_2.5 pollution by employing the data envelopment analysis (DEA) approach to a chance constrained stochastic optimization problem. This approach has the two advantages of admitting random input and output, and allowing the evaluation unit to exceed the front edge under the given probability constraint. Furthermore, by utilizing the meteorological observation data incorporated with the economic and social data for Jiangsu Province, the chance constrained stochastic DEA model was solved to explore the relationship between the meteorological elements and human activities and PM_2.5 pollution. The results are summarized by the following: (1) Among all five primary indexes, social progress, energy use and transportation are the most significant for PM_2.5 pollution. (2) Among our selected 14 secondary indexes, coal consumption, population density and civil car ownership account for a major portion of PM_2.5 pollution. (3) Human activities are the main factor producing PM_2.5 pollution. While some meteorological elements generate PM_2.5 pollution, some act as influencing factors on the migration of PM_2.5 pollution. These findings can provide a reference for the government to formulate appropriate policies to reduce PM_2.5 emissions and for the communities to develop effective strategies to eliminate PM_2.5 pollution.

Indirect effect of PM1 on endothelial cells via inducing the release of respiratory inflammatory cytokines

A large number of epidemiological studies have shown that increased cardiovascular morbidity and mortality are associated with exposure to high concentrations of PM_2.5. One of the ways that PM_2.5 affects the cardiovascular system is through systemic inflammation. Inflammatory cytokines such as TNF-α, IL-1β, IL-6, and IL-8 stimulate endothelial cells, which leads to endothelial dysfunction. Compared with PM_2.5, PM₁ is smaller in size, has a larger surface area and absorbs more toxic substances such as heavy metals, organic compounds, and black carbon. However, the effect of PM₁ on human health is less studied. Here, we used BEAS-2B cells and differentiated THP-1 cells to simulate epithelial cells and macrophages in the lung, respectively. The indirect effect of PM₁ on endothelial cells was studied with a coculture model consisting of two cell lines (BEAS-2B cells and macrophages) in the top compartment and one cell line, human umbilical vein endothelial cells (EA.hy926), in the bottom compartment of a transwell plate. The results showed that PM₁ could promote the release of inflammatory cytokines, including TNF-α and IL-6, from BEAS-2B cells and macrophages. In addition, PM₁ upregulated ICAM-1 expression in EA.hy926 cells through TNF-α/NF-κB signaling pathways, promoting the adhesion of endothelial cells and monocytes, a key event in the initiation of atherosclerosis.

The toxicology of air pollution predicts its epidemiology

The epidemiologic investigation has successively delineated associations of air pollution exposure with non-malignant and malignant lung disease, cardiovascular disease, cerebrovascular disease, pregnancy outcomes, perinatal effects and other extra-pulmonary disease including diabetes. Defining these relationships between air pollution exposure and human health closely parallels results of an earlier epidemiologic investigation into cigarette smoking and environmental tobacco smoke (ETS), two other particle-related exposures. Humic-like substances (HULIS) have been identified as a chemical component common to cigarette smoke and air pollution particles. Toxicology studies provide evidence that a disruption of iron homeostasis with sequestration of host metal by HULIS is a fundamental mechanistic pathway through which biological effects are initiated by cigarette smoke and air pollution particles. As a result of a common chemical component and a shared mechanistic pathway, it should be possible to extrapolate from the epidemiology of cigarette smoking and ETS to predict associations of air pollution exposure with human disease, which are currently unrecognized. Accordingly, it is anticipated that the forthcoming epidemiologic investigation will demonstrate relationships of air pollution with COPD causation, peripheral vascular disease, hypertension, renal disease, digestive disease, loss of bone mass/risk of fractures, dental disease, eye disease, fertility problems, and extrapulmonary malignancies.

Acute Effects of Particulate Air Pollution on Ischemic Stroke and Hemorrhagic Stroke Mortality

Background and Purpose: A large body of literature reported the association of particulate matter (PM) with stroke in high-income countries. Few studies have examined the association between PM and stroke in middle- and low-income countries and considered the types of stroke. In this study, we examined the short-term effects of particulate matter <2.5 μm in diameter (PM_2.5) and particulate matter <10 μm in diameter (PM₁₀) on ischemic stroke mortality and hemorrhagic stroke mortality in Beijing, China.

Methods: We used an ecological study design and quasi-Poisson generalized additive models to evaluate the association of PM_2.5 and PM₁₀ and cerebrovascular diseases mortality, as well as ischemic- and hemorrhagic stroke mortality. In the model, we controlled long-term and season trends, temperature, and relative humidity, the day of the week and air pollution. For cerebrovascular diseases mortality, we examined the effects stratified by sex and age with different lag days.

Results: A total of 48,122 deaths for cerebrovascular disease (32,799 deaths for ischemic stroke and 13,051 deaths for hemorrhagic stroke) were included in the study. PM_2.5 was associated with stroke mortality. The 10 μg/m³ increase of PM_2.5 was associated with the increase of mortality, 0.27% (95% CI, 0.12–0.43%) for cerebrovascular diseases, 0.23% (95% CI, 0.04–0.42%) for ischemic stroke and 0.37% (95% CI, 0.07–0.67%) for hemorrhagic stroke -. The associations between PM₁₀ and mortality were also detected for cerebrovascular diseases and ischemic stroke, but not in hemorrhagic stroke. The stratified analysis suggested age and gender did not modify the effects of PM on mortality significantly.

Conclusions: Our study suggested that short-term exposure to ambient PM was associated with the risk of stroke mortality.

Urban air pollution and climate change: "The Decalogue: Allergy Safe Tree" for allergic and respiratory diseases care

BACKGROUND

According to the World Health Organization, air pollution is closely associated with climate change and, in particular, with global warming. In addition to melting of ice and snow, rising sea level, and flooding of coastal areas, global warming is leading to a tropicalization of temperate marine ecosystems. Moreover, the effects of air pollution on airway and lung diseases are well documented as reported by the World Allergy Organization.

METHODS

Scientific literature was searched for studies investigating the effect of the interaction between air pollution and climate change on allergic and respiratory diseases.

RESULTS

Since 1990s, a multitude of articles and reviews have been published on this topic, with many studies confirming that the warming of our planet is caused by the "greenhouse effect" as a result of increased emission of "greenhouse" gases. Air pollution is also closely linked to global warming: the emission of hydrocarbon combustion products leads to increased concentrations of biological allergens such as pollens, generating a mixture of these particles called particulate matter (PM). The concept is that global warming is linked to the emission of hydrocarbon combustion products, since both carbon dioxide and heat increase pollen emission into the atmosphere, and all these particles make up PM10. However, the understanding of the mechanisms by which PM affects human health is still limited. Therefore, several studies are trying to determine the causes of global warming. There is also evidence that increased concentrations of air pollutants and pollens can activate inflammatory mediators in the airways. Our Task Force has prepared a Decalogue of rules addressing public administrators, which aims to limit the amount of allergenic pollen in the air without sacrificing public green areas.

CONCLUSIONS

Several studies underscore the significant risks of global warming on human health due to increasing levels of air pollution. The impact of climate change on respiratory diseases appears well documented. The last decades have seen a rise in the concentrations of pollens and pollutants in the air. This rise parallels the increase in the number of people presenting with allergic symptoms (e.g., allergic rhinitis, conjunctivitis, and asthma), who often require emergency medical care. Our hope is that scientists from different disciplines will work together with institutions, pharmaceutical companies and lay organizations to limit the adverse health effects of air pollution and global warming.