Ischemic and thrombotic effects of dilute diesel-exhaust inhalation in men with coronary heart disease

Mechanism underlying the role of integrin α3β1 in adhesive dysfunction between thyroid cells induced by diesel engine exhaust particles

The role and mechanisms of DEP exposure on thyroid injury are not yet clear. This study explores thyroid damage induced by in vivo DEP exposure using a mouse model. This study has observed alterations in thyroid follicular architecture, including rupture, colloid overflow, and the formation of voids. Additionally, there was a significant decrease in the expression levels of proteins involved in thyroid hormone synthesis, such as thyroid peroxidase and thyroglobulin, their trend of change is consistent with the damage to the thyroid structure. Serum levels of triiodothyronine and tetraiodothyronine were raise. However, the decrease in TSH expression suggests that the function of the HPT axis is unaffected. To delve deeper into the intrinsic mechanisms of thyroid injury, we performed KEGG pathway enrichment analysis, which revealed notable alterations in the cell adhesion signaling pathway. Our immunofluorescence results show that DEP exposure impairs thyroid adhesion, and integrin α3β1 plays an important role. CD151 binds to α3β1, promoting multimolecular complex formation and activating adhesion-dependent small GTPases. Our in vitro model has confirmed the pivotal role of integrin α3β1 in thyroid cell adhesion, which may be mediated by the CD151/α3β1/Rac1 pathway. In summary, exposure to DEP disrupts the structure and function of the thyroid, a process that likely involves the regulation of cell adhesion through the CD151/α3β1/Rac1 pathway, leading to glandular damage.

Bushfire-smoke trigger hospital admissions with cerebrovascular diseases: Evidence from 2019-20 bushfire in Australia

INTRODUCTION

Exposure to ambient air pollution is strongly associated with increased cerebrovascular diseases. The 2019-20 bushfire season in Australia burnt 5.4 million hectares of land in New South Wales alone, with smoke so severe it affected cities in Argentina, 11,000 km away. The smoke emitted by bushfires consists of both gaseous and particle components. It is important to note that exposure to particulate matter has been shown to be linked to a heightened risk of stroke, which is the primary kind of cerebrovascular illness, as well as an increased likelihood of hospitalisations and mortality. However, the available data is inadequate in terms of documenting the response of patients diagnosed with a proven cerebrovascular illness to bushfire smoke. Additionally, there is a lack of information about the health effects associated with particulate matter throughout the bushfire season and on days when smoke was present in 2019 and 2020.Therefore, we aimed to determine the effects of (i) short-term air pollution triggered by bushfires and (ii) high smoke days in increasing the daily number of hospital admissions with cerebrovascular diseases.

MATERIALS AND METHODS

Hospitalisation data were accessed from the admitted patient dataset from seven local Government areas of Hunter New England Local Health District. The bushfire period was defined from 1 October 2019 to 10 February 2020, and a same period from 2018-19 as the control. High bushfire smoke days were days when the average daily concentration of particulate matter was higher than the 95th percentile of the control period. Poisson regression models and fixed effect meta-analysis were used to analyse the data.

RESULTS

In total, 275 patients with cerebrovascular admissions were identified, with 147 (53.5%) during the bushfire (2019-20) and 128 (46.5%) in the control period (2018-19). There was no significant increase in daily admissions for cerebrovascular disease (Incidence Rate Ratio, IRR: 1.04; 95% CI: 0.81-1.34; p-value: 0.73), acute stroke (IRR: 1.15; 95% CI: 0.88-1.50; p-value: 0.29) or acute ischaemic stroke (IRR: 1.18; 95% CI: 0.87-1.59; p-value: 0.28), over the entire bushfire period. However, the high bushfire smoke days were associated with increased acute ischaemic stroke-related hospital admissions across lead 0-3 and the highest cumulative effect was observed with lead 0 (IRR:1.52; 95% CI: 1.01-2.29; p-value: 0.04). In addition, during the bushfire period, particulate matter, both PM10 and PM2.5 (defined as particulates that have an effective aerodynamic diameter of 10, and 2.5 microns, respectively), were also associated with increased acute ischaemic stroke admissions with a lag of 0-3 days.

DISCUSSION AND CONCLUSION

The results suggested a possible association between particulate matter and high smoke days with increased hospital admissions due to acute ischaemic stroke during the recent Australian bushfire season.

Diesel exhaust particles exposure exacerbates pro-thrombogenic plasma features ex-vivo after cerebral ischemia and accelerates tPA-induced clot-lysis in hypertensive subjects

The combustion of fossil fuels, mainly by diesel engines, generates Diesel Exhaust Particles (DEP) which are the main source of Particulate Matter (PM), a major air pollutant in urban areas. These particles are a risk factor for stroke with 5.6% of cases attributed to PM exposure. Our aim was to evaluate the effect of DEP exposure on clot formation and lysis in the context of stroke. An ex-vivo clot formation and lysis turbidimetric assay has been conducted in human and mouse plasma samples from ischemic stroke or control subjects exposed to DEP or control conditions. Experimental DEP exposure was achieved by nasal instillation in mice, or by ex-vivo exposure in human plasma. Results show consistent pro-thrombogenic features in plasma after human ischemic stroke and mouse cerebral ischemia (distal MCAo), boosted by the presence of DEP. Otherwise, thrombolysis times were increased after ischemia in chronically exposed mice but not in the DEP exposed group. Finally, subjects living in areas with high PM levels presented accelerated thrombolysis compared to those living in low polluted areas. Overall, our results point at a disbalance of the thrombogenic/lytic system in presence of DEP which could impact on ischemic stroke onset, clot size and thrombolytic treatment.

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

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

HIPTox-Hazard Identification Platform to Assess the Health Impacts from Indoor and Outdoor Air Pollutant Exposures, through Mechanistic Toxicology: A Single-Centre Double-Blind Human Exposure Trial Protocol

Over the past decade, our understanding of the impact of air pollution on short- and long-term population health has advanced considerably, focusing on adverse effects on cardiovascular and respiratory systems. There is, however, increasing evidence that air pollution exposures affect cognitive function, particularly in susceptible groups. Our study seeks to assess and hazard rank the cognitive effects of prevalent indoor and outdoor pollutants through a single-centre investigation on the cognitive functioning of healthy human volunteers aged 50 and above with a familial predisposition to dementia. Participants will all undertake five sequential controlled exposures. The sources of the air pollution exposures are wood smoke, diesel exhaust, cleaning products, and cooking emissions, with clean air serving as the control. Pre- and post-exposure spirometry, nasal lavage, blood sampling, and cognitive assessments will be performed. Repeated testing pre and post exposure to controlled levels of pollutants will allow for the identification of acute changes in functioning as well as the detection of peripheral markers of neuroinflammation and neuronal toxicity. This comprehensive approach enables the identification of the most hazardous components in indoor and outdoor air pollutants and further understanding of the pathways contributing to neurodegenerative diseases. The results of this project have the potential to facilitate greater refinement in policy, emphasizing health-relevant pollutants and providing details to aid mitigation against pollutant-associated health risks.

The effects of vitamin D on different types of cells

Vitamin D is neccessary for regulation of calcium and phosphorus metabolism in bones, affects imunity, the cardiovascular system, muscles, skin, epithelium, extracellular matrix, the central nervous system, and plays arole in prevention of aging-associated diseases. Vitamin D receptor is expressed in almost all types of cells and its activation leads to modulation of different signaling pathways. In this review, we have analysed the current knowledge of 1,25-dihydroxyvitamin D3 or 25-hydroxyvitamin D3 effects on metabolism of cells important for the function of the cardiovascular system (endothelial cells, vascular smooth muscle cells, cardiac cells and pericytes), tissue healing (fibroblasts), epithelium (various types of epithelial cells) and the central nervous system (neurons, astrocytes and microglia). The goal of this review was to compare the effects of vitamin D on the above mentioned cells in in vitro conditions and to summarize what is known in this field of research.

Impact of Short-Term Exposure to Nitrogen Dioxide (NO2) and Ozone (O3) on Hospital Admissions for Non-ST-Segment Elevation Acute Coronary Syndrome

In the context of recent climate change, global warming, industrial growth, and population expansion, air pollution has emerged as a significant environmental and human health risk. This study employed a multivariable Poisson regression analysis to examine the association between short-term exposure to atmospheric pollutants (nitrogen dioxide-NO2, sulfur dioxide -SO2, ozone-O3, and particulate matter with a diameter less than 10 μm-PM10) and hospital admissions for non-ST-segment elevation acute coronary syndrome (NSTE-ACS). Daily data on NSTE-ACS admissions, air pollutants, and meteorological variables were collected from January 2019 to December 2021. Elevated NO2 concentrations were associated with a higher risk of NSTE-ACS hospitalization, notably in spring (OR: 1.426; 95% CI: 1.196-1.701). Hypertensive individuals (OR: 1.101; 95% CI: 1.007-1.204) and those diagnosed with unstable angina (OR: 1.107; 95%CI: 1.010-1.213) exhibited heightened susceptibility to elevated NO2 concentrations. A 10 μg/m3 increase in NO2 during spring at lag 07 (OR: 1.013; 95% CI: 1.001-1.025) and O3 in winter at lag 05 (OR: 1.007; 95% CI: 1.001-1.014) was correlated with an elevated daily occurrence of NSTE-ACS admissions. Short-term exposure to various air pollutants posed an increased risk of NSTE-ACS hospitalization, with heightened sensitivity observed in hypertensive patients and those with unstable angina. Addressing emerging environmental risk factors is crucial to mitigate substantial impacts on human health and the environment.

Particulate Matter Air Pollution is a Significant Risk Factor for Cardiovascular Disease

Air pollution is responsible worldwide for 9-12 million deaths annually. The major contributor to air pollution is particulate matter ≤2.5 µg per cubic meter of air (PM2.5) from vehicles, industrial emissions, and wildfire smoke. United States ambient air standards recommend annual average PM2.5 concentrations of ≤12 μg/m³ while European standards allow an average annual PM2.5 concentration of ≤20 μg/m3. However, significant PM2.5 cardiovascular and pulmonary health risks exist below these concentrations. Chronic PM2.5 exposure significantly increases major cardiovascular and pulmonary event risks in Americans by 8 to more than 20% for each 10-μg/m3 increase in PM2.5. PM2.5-induced increases in lipid peroxidation, induction of vascular inflammation and endothelial cell injury initiate and propagate respiratory diseases, coronary and carotid atherosclerosis. PM2.5 can cause atherosclerotic vascular plaque rupture and myocardial infarction and stroke by activating metalloproteinases. This article discusses PM2.5 effects on the cardiovascular and pulmonary systems, specific PM2.5 pathophysiologic mechanisms contributing to cardiopulmonary disease, and preventive measures to limit the cardiovascular and pulmonary effects of PM2.5.

Redox and inflammatory mechanisms linking air pollution particulate matter with cardiometabolic derangements

Air pollution is the largest environmental risk factor for disease and premature death. Among the different components that are present in polluted air, fine particulate matter below 2.5 μm in diameter (PM2.5) has been identified as the main hazardous constituent. PM2.5 mainly arises from fossil fuel combustion during power generation, industrial processes, and transportation. Exposure to PM2.5 correlates with enhanced mortality risk from cardiovascular diseases (CVD), such as myocardial infarction and stroke. Over the last decade, it has been increasingly suggested that PM2.5 affects CVD already at the stage of risk factor development. Among the multiple biological mechanisms that have been described, the interplay between oxidative stress and inflammation has been consistently highlighted as one of the main drivers of pulmonary, systemic, and cardiovascular effects of PM2.5 exposure. In this context, PM2.5 uptake by tissue-resident immune cells in the lung promotes oxidative and inflammatory mediators release that alter tissue homeostasis at remote locations. This pathway is central for PM2.5 pathogenesis and might account for the accelerated development of risk factors for CVD, including obesity and diabetes. However, transmission and end-organ mechanisms that explain PM2.5-induced impaired function in metabolic active organs are not completely understood. In this review, the main features of PM2.5 physicochemical characteristics related to PM2.5 ability to induce oxidative stress and inflammation will be presented. Hallmark and recent epidemiological and interventional studies will be summarized and discussed in the context of current air quality guidelines and legislation, knowledge gaps, and inequities. Lastly, mechanistic studies at the intersection between redox metabolism, inflammation, and function will be discussed, with focus on heart and adipose tissue alterations. By offering an integrated analysis of PM2.5-induced effects on cardiometabolic derangements, this review aims to contribute to a better understanding of the pathogenesis and potential interventions of air pollution-related CVD.

Cigarette smoking and air pollution exposure and their effects on cardiovascular diseases

Cardiovascular disease (CVD) has no socioeconomic, topographical, or sex limitations as reported by the World Health Organization (WHO). The significant drivers of CVD are cardio-metabolic, behavioral, environmental, and social risk factors. However, some significant risk factors for CVD (e.g., a pitiable diet, tobacco smoking, and a lack of physical activities), have also been linked to an elevated risk of cardiovascular disease. Lifestyles and environmental factors are known key variables in cardiovascular disease. The familiarity with smoke goes along with the contact with the environment: air pollution is considered a source of toxins that contribute to the CVD burden. The incidence of myocardial infarction increases in males and females and may lead to fatal coronary artery disease, as confirmed by epidemiological studies. Lipid modification, inflammation, and vasomotor dysfunction are integral components of atherosclerosis development and advancement. These aspects are essential for the identification of atherosclerosis in clinical investigations. This article aims to show the findings on the influence of CVD on the health of individuals and human populations, as well as possible pathology and their involvement in smoking-related cardiovascular diseases. This review also explains lifestyle and environmental factors that are known to contribute to CVD, with indications suggesting an affiliation between cigarette smoking, air pollution, and CVD.

[Effects of air pollution on cardiovascular events in cardiac intensive care units]

Many environmental factors influence the occurrence of cardiovascular events. Among these, air pollution is certainly the most harmful, due to its dual composition and effects. Air pollution is both particulate and gaseous, and can vary in concentration and composition according to its source and type of emission. Moreover, clinical effects are not only observed at long-term but also at short-term, following rapid deterioration in air quality. Air pollution must therefore be seen both as a risk factor for atherosclerotic disease, and as a trigger for cardiovascular events. These acute effects are essentially mediated by an increased risk of acute coronary syndromes and heart failure. The effects of air pollution on admissions for ventricular arrhythmias and arterial hypertension are also possible. The cardiotoxicity of pollution is mainly mediated by sympatho-vagal imbalance, by the initiation and amplification of an oxidative, inflammatory and pro-aggregatory cascade, and by endothelial dysfunction and activation of metalloproteinases. Although now well established, the consequences of air pollution on acute cardiovascular events require further investigation. Environmental cardiology is an emerging discipline whose current vision still fails to integrate qualitative aspects, such as the oxidative potential of particulate matter, and the joint effects of multiple environmental exposures.

Effect of short-term exposure to air pollution on daily cardio- and cerebrovascular hospitalisations in areas with a low level of air pollution

Exposure to air pollution is associated with increased cardio- and cerebrovascular diseases. However, the evidence regarding the short-term effect of air pollution on cardio- and cerebrovascular hospitalisations in areas with relatively low air pollution levels is limited. This study aims to examine the effect of short-term exposure to different air pollutants on hospital admissions due to cardio- and cerebrovascular diseases in rural and regional Australia with low air pollution. The study was conducted in five local Government areas of Hunter New England Local Health District (HNE-LHD). Hospitalisation data from January 2018 to February 2020 (820 days) were accessed from the HNE-LHD admitted patients' dataset. Poisson regression model was used to examine the association between the exposure (air pollutants) and outcome variables (hospitalisation due to cardio- and cerebrovascular disease). The concentrations of gaseous air pollutants, Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), Ozone (O3), Carbon Monoxide (CO), and Ammonia (NH3) were below national benchmark concentrations for every day of the study period. In single pollutant models, SO2 and NO2 significantly increased the daily number of cardio- and cerebrovascular hospitalisations. The highest cumulative effect for SO2 was observed across lag 0-3 days (Incidence Rate Ratio, IRR: 1.77; 95% Confidence Interval, CI: 1.18-2.65; p-value: 0.01), and for NO2, it was across lag 0-2 days (IRR: 1.13; 95% CI: 1.02-1.25; p-value: 0.02). In contrast, higher O3 was associated with decreased cardio- and cerebrovascular hospitalisations, with the largest effect observed at lag 0 (IRR: 0.94; 95% CI: 0.89-0.98; p-value: 0.02). In the multi-pollutant model, the effect of NO2 remained significant at lag 0 and corresponded to a 21% increase in cardio- and cerebrovascular hospitalisation (95% CI: 1-44%; p-value = 0.04). Thus, the study revealed that gaseous air pollutants, specifically NO2, were positively related to increased cardio- and cerebrovascular hospitalisations, even at concentrations below the national standards.

The contribution of the exposome to the burden of cardiovascular disease

Large epidemiological and health impact assessment studies at the global scale, such as the Global Burden of Disease project, indicate that chronic non-communicable diseases, such as atherosclerosis and diabetes mellitus, caused almost two-thirds of the annual global deaths in 2020. By 2030, 77% of all deaths are expected to be caused by non-communicable diseases. Although this increase is mainly due to the ageing of the general population in Western societies, other reasons include the increasing effects of soil, water, air and noise pollution on health, together with the effects of other environmental risk factors such as climate change, unhealthy city designs (including lack of green spaces), unhealthy lifestyle habits and psychosocial stress. The exposome concept was established in 2005 as a new strategy to study the effect of the environment on health. The exposome describes the harmful biochemical and metabolic changes that occur in our body owing to the totality of different environmental exposures throughout the life course, which ultimately lead to adverse health effects and premature deaths. In this Review, we describe the exposome concept with a focus on environmental physical and chemical exposures and their effects on the burden of cardiovascular disease. We discuss selected exposome studies and highlight the relevance of the exposome concept for future health research as well as preventive medicine. We also discuss the challenges and limitations of exposome studies.

Sex Associations Between Air Pollution and Estimated Atherosclerotic Cardiovascular Disease Risk Determination

Objective: The purpose of this study was to investigate the sex correlations of particulate matters (PM2.5, PM10, PM2.5-10), NO2 and NOx with ASCVD risk in the UK Biobank population. Methods: Among 285,045 participants, pollutants were assessed and correlations between ASCVD risk were stratified by sex and estimated using multiple linear and logistic regressions adjusted for length of time at residence, education, income, physical activity, Townsend deprivation, alcohol, smocking pack years, BMI and rural/urban zone. Results: Males presented higher ASCVD risk than females (8.63% vs. 2.65%, p < 0.001). In males PM2.5, PM10, NO2, and NOx each were associated with an increased ASCVD risk >7.5% in the adjusted logistic models, with ORs [95% CI] for a 10 μg/m3 increase were 2.17 [1.87-2.52], 1.15 [1.06-1.24], 1.06 [1.04-1.08] and 1.05 [1.04-1.06], respectively. In females, the ORs for a 10 μg/m3 increase were 1.55 [1.19-2.05], 1.22 [1.06-1.42], 1.07 [1.03-1.10], and 1.04 [1.02-1.05], respectively. No association was observed in both sexes between ASCVD risk and PM2.5-10. Conclusion: Our findings may suggest the possible actions of air pollutants on ASCVD risk.

Can traffic-related air pollution trigger myocardial infarction within a few hours of exposure? Identifying hourly hazard periods

INTRODUCTION

Traffic-related air pollution can trigger myocardial infarction (MI). However, the hourly hazard period of exposure to nitrogen dioxide (NO2), a common traffic tracer, for incident MI has not been fully evaluated. Thus, the current hourly US national air quality standard (100 ppb) is based on limited hourly-level effect estimates, which may not adequately protect cardiovascular health.

OBJECTIVES

We characterized the hourly hazard period of NO2 exposure for MI in New York state (NYS), USA, from 2000 to 2015.

METHODS

For nine cities in NYS, we obtained data on MI hospitalizations from the NYS Department of Health Statewide Planning and Research Cooperative System and hourly NO2 concentrations from the US Environmental Protection Agency's Air Quality System database. We used city-wide exposures and a case-crossover study design with distributed lag non-linear terms to assess the relationship between hourly NO2 concentrations over 24 h and MI, adjusting for hourly temperature and relative humidity.

RESULTS

The mean NO2 concentration was 23.2 ppb (standard deviation: 12.6 ppb). In the six hours preceding MI, we found linearly increased risk with increasing NO2 concentrations. At lag hour 0, a 10 ppb increase in NO2 was associated with 0.2 % increased risk of MI (Rate Ratio [RR]: 1.002; 95 % Confidence Interval [CI]: 1.000, 1.004). We estimated a cumulative RR of 1.015 (95 % CI: 1.008, 1.021) for all 24 lag hours per 10 ppb increase in NO2. Lag hours 2-3 had consistently elevated risk ratios in sensitivity analyses.

CONCLUSIONS

We found robust associations between hourly NO2 exposure and MI risk at concentrations far lower than current hourly NO2 national standards. Risk of MI was most elevated in the six hours after exposure, consistent with prior studies and experimental work evaluating physiologic responses after acute traffic exposure. Our findings suggest that current hourly standards may be insufficient to protect cardiovascular health.

Analysis of the relationship between ambient air pollution and the severity of heart failure decompensations in two Spanish metropolises (Barcelona and Madrid)

OBJECTIVES

To analyze whether the high levels of air pollutants are related to a greater severity of decompensated heart failure (HF).

METHOD

Patients diagnosed with decompensated HF in the emergency department of 4 hospitals in Barcelona and 3 in Madrid were included. Clinical data (age, sex, comorbidities, baseline functional status), atmospheric (temperature, atmospheric pressure) and pollutant data (SO₂, NO₂, CO, O₃, PM₁₀, PM_2.5) were collected in the city on the day of emergency care. The severity of decompensation was estimated using 7-day mortality (primary indicator) and the need for hospitalization, in-hospital mortality, and prolonged hospitalization (secondary indicators). The association adjusted for clinical, atmospheric and city data between pollutant concentration and severity was investigated using linear regression (linearity assumption) and restricted cubic spline curves (no linearity assumption).

RESULTS

A total of 5292 decompensations were included, with a median age of 83 years (IQR=76-88) and 56% women. The medians (IQR) of the daily pollutant averages were: SO₂=2.5μg/m³ (1.4-7.0), NO₂=43μg/m³ (34-57), CO=0.48mg/m³ (0.35-0.63), O₃=35μg/m³ (25-48), PM₁₀=22μg/m³ (15-31) and PM_2.5=12μg/m³ (8-17). Mortality at 7 days was 3.9%, and hospitalization, in-hospital mortality, and prolonged hospitalization were 78.9, 6.9, and 47.5%, respectively. SO₂ was the only pollutant that showed a linear association with the severity of decompensation, since each unit of increase implied an OR for the need for hospitalization of 1.04 (95% CI 1.01-1.08). The restricted cubic spline curves study also did not show clear associations between pollutants and severity, except for SO₂ and hospitalization, with OR of 1.55 (95% CI 1.01-2.36) and 2.71 (95% CI 1.13-6.49) for concentrations of 15 and 24μg/m³, respectively, in relation to a reference concentration of 5μg/m³.

CONCLUSION

Exposure to ambient air pollutants, in a medium to low concentration range, is generally not related to the severity of HF decompensations, and only NO₂ may be associated with an increased need for hospitalization.

Respiratory Health Effects of In Vivo Sub-Chronic Diesel and Biodiesel Exhaust Exposure

Biodiesel, which can be made from a variety of natural oils, is currently promoted as a sustainable, healthier replacement for commercial mineral diesel despite little experimental data supporting this. The aim of our research was to investigate the health impacts of exposure to exhaust generated by the combustion of diesel and two different biodiesels. Male BALB/c mice (n = 24 per group) were exposed for 2 h/day for 8 days to diluted exhaust from a diesel engine running on ultra-low sulfur diesel (ULSD) or Tallow or Canola biodiesel, with room air exposures used as control. A variety of respiratory-related end-point measurements were assessed, including lung function, responsiveness to methacholine, airway inflammation and cytokine response, and airway morphometry. Exposure to Tallow biodiesel exhaust resulted in the most significant health impacts compared to Air controls, including increased airway hyperresponsiveness and airway inflammation. In contrast, exposure to Canola biodiesel exhaust resulted in fewer negative health effects. Exposure to ULSD resulted in health impacts between those of the two biodiesels. The health effects of biodiesel exhaust exposure vary depending on the feedstock used to make the fuel.

Applying principal component pursuit to investigate the association between source-specific fine particulate matter and myocardial infarction hospitalizations in New York City

The association between fine particulate matter (PM_2.5) and cardiovascular outcomes is well established. To evaluate whether source-specific PM_2.5 is differentially associated with cardiovascular disease in New York City (NYC), we identified PM_2.5 sources and examined the association between source-specific PM_2.5 exposure and risk of hospitalization for myocardial infarction (MI).

Methods

We adapted principal component pursuit (PCP), a dimensionality-reduction technique previously used in computer vision, as a novel pattern recognition method for environmental mixtures to apportion speciated PM_2.5 to its sources. We used data from the NY Department of Health Statewide Planning and Research Cooperative System of daily city-wide counts of MI admissions (2007-2015). We examined associations between same-day, lag 1, and lag 2 source-specific PM_2.5 exposure and MI admissions in a time-series analysis, using a quasi-Poisson regression model adjusting for potential confounders.

Results

We identified four sources of PM_2.5 pollution: crustal, salt, traffic, and regional and detected three single-species factors: cadmium, chromium, and barium. In adjusted models, we observed a 0.40% (95% confidence interval [CI]: -0.21, 1.01%) increase in MI admission rates per 1 μg/m³ increase in traffic PM_2.5, a 0.44% (95% CI: -0.04, 0.93%) increase per 1 μg/m³ increase in crustal PM_2.5, and a 1.34% (95% CI: -0.46, 3.17%) increase per 1 μg/m³ increase in chromium-related PM_2.5, on average.

Conclusions

In our NYC study, we identified traffic, crustal dust, and chromium PM_2.5 as potentially relevant sources for cardiovascular disease. We also demonstrated the potential utility of PCP as a pattern recognition method for environmental mixtures.

PM2.5 exposure exacerbates mice thoracic aortic aneurysm and dissection by inducing smooth muscle cell apoptosis via the MAPK pathway

Air pollution is a major public health concern worldwide. Exposure to fine particulate matter (PM2.5) is closely associated with cardiovascular diseases. However, the effect of PM2.5 exposure on thoracic aortic aneurysm and dissection (TAAD) has not been fully elucidated. Diesel exhaust particulate (DEP) is an important component of PM2.5, which causes health effects and is closely related to the incidence of cardiovascular disease. In the current study, we found that DEP exposure increased the incidence of aortic dissection (AD) in β-aminopropionitrile (BAPN)-induced thoracic aortic aneurysm (TAA). In addition, exposure to PM2.5 increased the diameter of the thoracic aorta in mice models. The number of apoptotic cells increased in the aortic wall of PM2.5-treated mice, as did the protein expression level of BAX/Bcl2 and cleaved caspase3/caspase3. Using a rhythmically stretching aortic mechanical simulation model, fluorescent staining indicated that PM2.5 administration could induce mitochondrial dysfunction and increase reactive oxygen species (ROS) levels in human aortic smooth muscle cells (HASMCs). Furthermore, ERK1/2 mitogen-activated protein kinase (MAPK) signaling pathways participated in the apoptosis of HASMCs after PM2.5 exposure. Therefore, we concluded that PM2.5 exposure could exacerbate the progression of TAAD, which could be induced by the increased apoptosis in HASMCs through the ERK1/2 MAPK signaling pathway.

Inequities in ambient fine particulate matter: A spatiotemporal analysis in Canadian communities

BACKGROUND

Exposure to fine particulate matter (PM_2.5) is associated with adverse health outcomes but communities are not randomly exposed to PM_2.5. Previous cross-sectional environmental injustice analyses in Canada found disproportionately higher exposure to PM_2.5 in low-income populations, visible minorities and immigrants. Beyond static surveillance, it is also important to evaluate how changes in PM_2.5 exposure over time may differentially impact disadvantaged communities. We examine whether communities with different sociodemographic characteristics benefited equitably from the overall decreases in ambient concentrations of PM_2.5 from 2001 to 2016 in Canada.

METHODS

We derived census tract level estimates of average annual PM_2.5 using validated satellite-based estimations of annual average PM_2.5 concentration surfaces. We investigated how the spatial distribution of PM_2.5 has evolved over 15 years (2001-2016) by comparing absolute values and rank percentiles of census tract level annual average PM_2.5 concentrations in 2001 and 2016. Using decennial census data and multivariable linear regression, we determined if sociodemographic characteristics are associated with changes in exposure to PM_2.5, accounting for geographic boundary changes between census periods.

RESULTS

Overall, ambient PM_2.5 concentrations decreased from 2001 (median of 9.1 μg/m³) to 2016 (median of 6.4 μg/m³), with varying provincial patterns. Across communities, ranked census tract specific PM_2.5 in 2001 and in 2016 are highly correlated (Spearman's rho = 0.75). We found that, on average and accounting for provincial differences and baseline PM_2.5, communities with greater density of aboriginal population, lower education, higher shelter-cost-to-income ratio, unemployment or lower income experienced smaller absolute decreases in PM_2.5 from 2001 to 2016.

CONCLUSIONS

Identifying sociodemographic groups that benefit least from decreasing exposure to PM_2.5 highlights the need to consider environmental injustice when designing or revising air pollution policies.

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.

Aluminum Nanoparticles Affect Human Platelet Function In Vitro

Endoprostheses are prone to tribological wear and biological processes that lead to the release of particles, including aluminum nanoparticles (Al NPs). Those particles can diffuse into circulation. However, the toxic effects of NPs on platelets have not been comprehensively analyzed. The aim of our work was to investigate the impact of Al NPs on human platelet function using a novel quartz crystal microbalance with dissipation (QCM-D) methodology. Moreover, a suite of assays, including light transmission aggregometry, flow cytometry, optical microscopy and transmission electron microscopy, were utilized. All Al NPs caused a significant increase in dissipation (D) and frequency (F), indicating platelet aggregation even at the lowest tested concentration (0.5 µg/mL), except for the largest (80 nm) Al NPs. A size-dependent effect on platelet aggregation was observed for the 5-20 nm NPs and the 30-50 nm NPs, with the larger Al NPs causing smaller increases in D and F; however, this was not observed for the 20-30 nm NPs. In conclusion, our study showed that small (5-50 nm) Al NPs caused platelet aggregation, and larger (80 nm) caused a bridging-penetrating effect in entering platelets, resulting in the formation of heterologous platelet-Al NPs structures. Therefore, physicians should consider monitoring NP serum levels and platelet activation indices in patients with orthopedic implants.

[Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment]

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

Environment and cardiovascular health: causes, consequences and opportunities in prevention and treatment

The environment is a strong determinant of cardiovascular health. Environmental cardiology studies the contribution of environmental exposures with the aim of minimizing the harmful influences of pollution and promoting cardiovascular health through specific preventive or therapeutic strategies. The present review focuses on particulate matter and metals, which are the pollutants with the strongest level of scientific evidence, and includes possible interventions. Legislation, mitigation and control of pollutants in air, water and food, as well as environmental policies for heart-healthy spaces, are key measures for cardiovascular health. Individual strategies include the chelation of divalent metals such as lead and cadmium, metals that can only be removed from the body via chelation. The TACT (Trial to Assess Chelation Therapy, NCT00044213) clinical trial demonstrated cardiovascular benefit in patients with a previous myocardial infarction, especially in those with diabetes. Currently, the TACT2 trial (NCT02733185) is replicating the TACT results in people with diabetes. Data from the United States and Argentina have also shown the potential usefulness of chelation in severe peripheral arterial disease. More research and action in environmental cardiology could substantially help to improve the prevention and treatment of cardiovascular disease.

Adverse effects of air pollution-derived fine particulate matter on cardiovascular homeostasis and disease

Air pollution is a rapidly growing major health concern around the world. Atmospheric particulate matter that has a diameter of less than 2.5 µm (PM2.5) refers to an air pollutant composed of particles and chemical compounds that originate from various sources. While epidemiological studies have established the association between PM2.5 exposure and cardiovascular diseases, the precise cellular and molecular mechanisms by which PM2.5 promotes cardiovascular complications are yet to be fully elucidated. In this review, we summarize the various sources of PM2.5, its components, and the concentrations of ambient PM2.5 in various settings. We discuss the experimental findings to date that evaluate the potential adverse effects of PM2.5 on cardiovascular homeostasis and function, and the possible therapeutic options that may alleviate PM2.5-driven cardiovascular damage.

Arterial stiffness, endothelial dysfunction and impaired fibrinolysis are pathogenic mechanisms contributing to cardiovascular risk in ANCA-associated vasculitis

Cardiovascular disease is a complication of systemic inflammatory diseases including anti-neutrophil cytoplasm antibody-associated vasculitis (AAV). The mechanisms of cardiovascular morbidity in AAV are poorly understood, and risk-reduction strategies are lacking. Therefore, in a series of double-blind, randomized case-control forearm plethysmography and crossover systemic interventional studies, we examined arterial stiffness and endothelial function in patients with AAV in long-term disease remission and in matched healthy volunteers (32 each group). The primary outcome for the case-control study was the difference in endothelium-dependent vasodilation between health and AAV, and for the crossover study was the difference in pulse wave velocity (PWV) between treatment with placebo and selective endothelin-A receptor antagonism. Parallel in vitro studies of circulating monocytes and platelets explored mechanisms. Compared to healthy volunteers, patients with AAV had 30% reduced endothelium-dependent vasodilation and 50% reduced acute release of endothelial active tissue plasminogen activator (tPA), both significant in the case-control study. Patients with AAV had significantly increased arterial stiffness (PWV: 7.3 versus 6.4 m/s). Plasma endothelin-1 was two-fold higher in AAV and independently predicted PWV and tPA release. Compared to placebo, both selective endothelin-A and dual endothelin-A/B receptor blockade reduced PWV and increased tPA release in AAV in the crossover study. Mechanistically, patients with AAV had increased platelet activation, more platelet-monocyte aggregates, and altered monocyte endothelin receptor function, reflecting reduced endothelin-1 clearance. Patients with AAV in long-term remission have elevated cardiovascular risk and endothelin-1 contributes to this. Thus, our data support a role for endothelin-blockers to reduce cardiovascular risk by reducing arterial stiffness and increasing circulating tPA activity.

Pro-thrombotic changes associated with exposure to ambient ultrafine particles in patients with chronic obstructive pulmonary disease: roles of lipid peroxidation and systemic inflammation

BACKGROUND

Exposure to particulate matter air pollution is associated with an increased risk of cardiovascular mortality in patients with chronic obstructive pulmonary disease (COPD), but the underlying mechanisms are not yet understood. Enhanced platelet and pro-thrombotic activity in COPD patients may explain their increased cardiovascular risk. We aim to explore whether short-term exposure to ambient particulate matter is associated with pro-thrombotic changes in adults with and without COPD, and investigate the underlying biological mechanisms in a longitudinal panel study. Serum concentration of thromboxane (Tx)B2 was measured to reflect platelet and pro-thrombotic activity. Lipoxygenase-mediated lipid peroxidation products (hydroxyeicosatetraenoic acids [HETEs]) and inflammatory biomarkers (interleukins [ILs], monocyte chemoattractant protein-1 [MCP-1], tumour necrosis factor alpha [TNF-α], and macrophage inflammatory proteins [MIPs]) were measured as potential mediating determinants of particle-associated pro-thrombotic changes.

RESULTS

53 COPD and 82 non-COPD individuals were followed-up on a maximum of four visits conducted from August 2016 to September 2017 in Beijing, China. Compared to non-COPD individuals, the association between exposure to ambient ultrafine particles (UFPs) during the 3-8 days preceding clinical visits and the TxB2 serum concentration was significantly stronger in COPD patients. For example, a 10³/cm³ increase in the 6-day average UFP level was associated with a 25.4% increase in the TxB2 level in the COPD group but only an 11.2% increase in the non-COPD group. The association in the COPD group remained robust after adjustment for the levels of fine particulate matter and gaseous pollutants. Compared to the non-COPD group, the COPD group also showed greater increases in the serum concentrations of 12-HETE (16.6% vs. 6.5%) and 15-HETE (9.3% vs. 4.5%) per 10³/cm³ increase in the 6-day UFP average. The two lipid peroxidation products mediated 35% and 33% of the UFP-associated increase in the TxB2 level of COPD patients. UFP exposure was also associated with the increased levels of IL-8, MCP-1, MIP-1α, MIP-1β, TNF-α, and IL-1β in COPD patients, but these inflammatory biomarkers did not mediate the TxB2 increase.

CONCLUSIONS

Short-term exposure to ambient UFPs was associated with a greater pro-thrombotic change among patients with COPD, at least partially driven by lipoxygenase-mediated pathways following exposure. Trial registration ChiCTR1900023692 . Date of registration June 7, 2019, i.e. retrospectively registered.

The Impact of Meteorological Factors and Air Pollutants on Acute Coronary Syndrome

Purpose of Review

Several studies have found that air pollution and climate change can have an impact on acute coronary syndromes (ACS), the leading cause of death worldwide. We synthesized the latest information about the impact of air pollution and climate change on ACS, the latest data about the pathophysiological mechanisms of meteorological factors and atmospheric pollutants on atherosclerotic disease, and an overall image of air pollution and coronary heart disease in the context of the COVID-19 pandemic.

Recent Findings

The variation of meteorological factors in different seasons increased the risk of ACS. Both the increase and the decrease in apparent temperature were found to be risk factors for ACS admissions. It was also demonstrated that exposure to high concentrations of air pollutants, especially particulate matter, increased cardiovascular morbidity and mortality.

Summary

Climate change as well as increased emissions of air pollutants have a major impact on ACS. The industrialization era and the growing population cause a constant increase in air pollution worldwide. Thus, the number of ACS favored by air pollution and the variations in meteorological factors is expected to increase dramatically in the next few years.

The Impact of Fine Particulate Matter 2.5 on the Cardiovascular System: A Review of the Invisible Killer

Air pollution exerts several deleterious effects on the cardiovascular system, with cardiovascular disease (CVD) accounting for 80% of all premature deaths caused by air pollution. Short-term exposure to particulate matter 2.5 (PM_2.5) leads to acute CVD-associated deaths and nonfatal events, whereas long-term exposure increases CVD-associated risk of death and reduces longevity. Here, we summarize published data illustrating how PM_2.5 may impact the cardiovascular system to provide information on the mechanisms by which it may contribute to CVDs. We provide an overview of PM_2.5, its associated health risks, global statistics, mechanistic underpinnings related to mitochondria, and hazardous biological effects. We elaborate on the association between PM_2.5 exposure and CVD development and examine preventive PM_2.5 exposure measures and future strategies for combating PM_2.5-related adverse health effects. The insights gained can provide critical guidelines for preventing pollution-related CVDs through governmental, societal, and personal measures, thereby benefitting humanity and slowing climate change.

Air pollution and cardiovascular disease: the Paul Wood Lecture, British Cardiovascular Society 2021

Air pollution is associated with up to 8.8 million excess deaths worldwide each year and is a major contributor to the global burden of disease. Cardiovascular conditions are the predominant cause for air pollution-related deaths and there is an urgent need to address the silent pandemic of air pollution on cardiovascular health. Air pollution exposure is associated with acute events like acute coronary syndrome and stroke, and with chronic conditions, such as atherosclerosis and heart failure. Several potential mechanisms have been proposed that link particle inhalation to cardiovascular disease including oxidative stress and inflammation, changes in autonomic balance and neuroendocrine regulation and the particle translocation into the circulation itself. This, in turn, can cause endothelial, vasomotor and fibrinolytic dysfunction and increased thrombogenicity and blood pressure which are implicated in the mediation of adverse cardiovascular events. Certain interventions can help mitigate these adverse effects. At an individual level, this includes the use of a facemask and indoor air purification systems. At an environmental level, interventions reducing the generation or release of combustion-derived pollutants are key and include public health policies to facilitate active transport, cleaner sources of energy and reductions in vehicular and fossil fuel emissions. In this review, we summarise the key pathways and mechanisms that draw together how air pollution can lead to adverse cardiovascular effects, as well as explore potential interventions to reduce the burden of air pollution-induced cardiovascular morbidity and mortality.

Air Pollution and Its Devastating Effects on the Central Nervous System

Air pollution is a real public health problem, it being one of the five most common causes of mortality in developing countries. However, pollution studies have focused on the cardiovascular and pulmonary systems in recent decades. Recently, researchers have moved towards a new direction, tracing a direct link between pollution and stroke. Stroke has many known risk factors such as smoking, a sedentary lifestyle, and hypertension. Pollution is universally widespread, already a matter of public interest, so that, although intuitive, it is difficult to connect the two. The particles found in the air that we breathe, regardless of their origin, can attack the body in different ways, causing inflammation, and triggering a true cascade of phenomena that end up attacking the central nervous system and other organs. This article tries to explain the series of phenomena that determine the harmful effect of particles present in the air, with an increased focus on the central nervous system and especially on strokes. A deeper understanding of these phenomena helps in guiding future studies and finding viable solutions to protect people at risk.

Incident cardiovascular disease and long-term exposure to source-specific air pollutants in a Swedish cohort

BACKGROUND

Air pollution is associated with cardiovascular morbidity and mortality, but its role in the development of congestive heart failure (CHF) and the role of different pollution sources in cardiovascular disease remain uncertain.

METHODS

Participants were enrolled in the Malmö Diet and Cancer cohort in 1991-1996 with information on lifestyle and clinical indicators of cardiovascular disease. The cohort participants were followed through registers until 2016. Annual total and local source-specific concentrations of particulate matter less than 10 μm and 2.5 μm (PM₁₀ and PM_2.5), black carbon (BC), and nitrogen oxides (NO_x) from traffic, residential heating, and industry were assigned to each participant's address throughout the study period. Cox proportional hazards models adjusted for possible confounders was used to estimate associations between air pollution 1-5 years prior to outcomes of incident CHF, fatal myocardial infarction (MI), major adverse coronary events (MACE), and ischemic stroke.

RESULTS

Air pollution exposure levels (mean annual exposures to PM_2.5 of 11 μg/m³ and NO_x of 26 μg/m³) within the cohort were moderate in terms of environmental standards. After adjusting for confounders, we observed statistically significant associations between NO_x and CHF (hazard ratio [HR] 1.11, 95% confidence interval [CI] 1.01-1.22) and NO_x and fatal MI (HR 1.10, 95%CI 1.01-1.20) per interquartile range (IQR) of 9.6 μg/m³. In fully adjusted models, the estimates were similar, but the precision worse. In stratified analyses, the associations were stronger in males, ever-smokers, older participants, and those with baseline carotid artery plaques. Locally emitted and traffic-related air pollutants generally showed positive associations with CHF and fatal MI. There were no associations between air pollution and MACE or stroke.

DISCUSSION/CONCLUSION

In an area with low to moderate air pollution exposure, we observed significant associations of long-term residential NO_x with increased risk of incident CHF and fatal MI, but not with coronary events and stroke.

Influence of air pollutants on circulating inflammatory cells and microRNA expression in acute myocardial infarction

Air pollutants increase the risk and mortality of myocardial infarction (MI). The aim of this study was to assess the inflammatory changes in circulating immune cells and microRNAs in MIs related to short-term exposure to air pollutants. We studied 192 patients with acute coronary syndromes and 57 controls with stable angina. For each patient, air pollution exposure in the 24-h before admission, was collected. All patients underwent systematic circulating inflammatory cell analyses. According to PM_2.5 exposure, 31 patients were selected for microRNA analyses. STEMI patients exposed to PM_2.5 showed a reduction of CD4⁺ regulatory T cells. Furthermore, in STEMI patients the exposure to PM_2.5 was associated with an increase of miR-146a-5p and miR-423-3p. In STEMI and NSTEMI patients PM_2.5 exposure was associated with an increase of miR-let-7f-5p. STEMI related to PM_2.5 short-term exposure is associated with changes involving regulatory T cells, miR-146a-5p and miR-423-3p.

Combined exposure to fine particulate matter and high glucose aggravates endothelial damage by increasing inflammation and mitophagy: the involvement of vitamin D

Background

Cardiovascular diseases (CVDs) are related to particulate matter (PM_2.5) exposure. Researchers have not clearly determined whether hyperglycemia, a hallmark of diabetes, exacerbates PM_2.5-induced endothelial damage. Thus, this study aimed to investigate the combined effects of PM_2.5 and high glucose on endothelial damage.

Results

Here, we treated human umbilical vein endothelial cells (HUVECs) with 30 mM high glucose and 50 μg/mL PM (HG + PM) to simulate endothelial cells exposed to hyperglycemia and air pollution. First, we showed that HUVECs exposed to PM under high glucose conditions exhibited significant increases in cell damage and apoptosis compared with HUVECs exposed to PM or HG alone. In addition, PM significantly increased the production of reactive oxygen species (ROS) in HUVECs and mitochondria treated with HG and decreased the expression of superoxide dismutase 1 (SOD1), a free radical scavenging enzyme. The coexposure group exhibited significantly increased ROS production in cells and mitochondria, a lower mitochondrial membrane potential, and increased levels of the autophagy-related proteins p62, microtubule-associated protein 1 light chain 3β (LC3B), and mitophagy-related protein BCL2 interacting protein 3 (Bnip3). Moreover, autophagosome-like structures were observed in the HG + PM group using transmission electron microscopy. The expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were also increased through the JNK/p38 signaling pathway in the HG + PM group. As a ROS scavenger, vitamin D treatment effectively protected cells under HG and PM conditions by increasing cell viability, reducing mitochondrial ROS production, and suppressing the formation of mitophagy and inflammation. Furthermore, diabetes was induced in mice by administering streptozotocin (STZ). Mice were treated with PM by intratracheal injection. Vitamin D effectively alleviated oxidative stress, mitophagy, and inflammation in the aortas of mice treated with STZ and PM.

Conclusion

Taken together, simultaneous exposure to PM and high glucose exerts significant harmful effects on endothelial cells by inducing ROS production, mitophagy, and inflammation, while vitamin D reverses these effects.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-022-00462-1.

Controlled human exposure to diesel exhaust: a method for understanding health effects of traffic-related air pollution

Diesel exhaust (DE) is a major component of air pollution in urban centers. Controlled human exposure (CHE) experiments are commonly used to investigate the acute effects of DE inhalation specifically and also as a paradigm for investigating responses to traffic-related air pollution (TRAP) more generally. Given the critical role this model plays in our understanding of TRAP's health effects mechanistically and in support of associated policy and regulation, we review the methodology of CHE to DE (CHE-DE) in detail to distill critical elements so that the results of these studies can be understood in context. From 104 eligible publications, we identified 79 CHE-DE studies and extracted information on DE generation, exposure session characteristics, pollutant and particulate composition of exposures, and participant demographics. Virtually all studies had a crossover design, and most studies involved a single DE exposure per participant. Exposure sessions were typically 1 or 2 h in duration, with participants alternating between exercise and rest. Most CHE-DE targeted a PM concentration of 300 μg/m3. There was a wide range in commonly measured co-pollutants including nitrogen oxides, carbon monoxide, and total organic compounds. Reporting of detailed parameters of aerosol composition, including particle diameter, was inconsistent between studies, and older studies from a given lab were often cited in lieu of repeating measurements for new experiments. There was a male predominance in participants, and over half of studies involved healthy participants only. Other populations studied include those with asthma, atopy, or metabolic syndrome. Standardization in reporting exposure conditions, potentially using current versions of engines with modern emissions control technology, will allow for more valid comparisons between studies of CHE-DE, while recognizing that diesel engines in much of the world remain old and heterogeneous. Inclusion of female participants as well as populations more susceptible to TRAP will broaden the applicability of results from CHE-DE studies.

Controlled human exposure to diesel exhaust: results illuminate health effects of traffic-related air pollution and inform future directions

Air pollution is an issue of increasing interest due to its globally relevant impacts on morbidity and mortality. Controlled human exposure (CHE) studies are often employed to investigate the impacts of pollution on human health, with diesel exhaust (DE) commonly used as a surrogate of traffic related air pollution (TRAP). This paper will review the results derived from 104 publications of CHE to DE (CHE-DE) with respect to health outcomes. CHE-DE studies have provided mechanistic evidence supporting TRAP’s detrimental effects on related to the cardiovascular system (e.g., vasomotor dysfunction, inhibition of fibrinolysis, and impaired cardiac function) and respiratory system (e.g., airway inflammation, increased airway responsiveness, and clinical symptoms of asthma). Oxidative stress is thought to be the primary mechanism of TRAP-induced effects and has been supported by several CHE-DE studies. A historical limitation of some air pollution research is consideration of TRAP (or its components) in isolation, limiting insight into the interactions between TRAP and other environmental factors often encountered in tandem. CHE-DE studies can help to shed light on complex conditions, and several have included co-exposure to common elements such as allergens, ozone, and activity level. The ability of filters to mitigate the adverse effects of DE, by limiting exposure to the particulate fraction of polluted aerosols, has also been examined. While various biomarkers of DE exposure have been evaluated in CHE-DE studies, a definitive such endpoint has yet to be identified. In spite of the above advantages, this paradigm for TRAP is constrained to acute exposures and can only be indirectly applied to chronic exposures, despite the critical real-world impact of living long-term with TRAP. Those with significant medical conditions are often excluded from CHE-DE studies and so results derived from healthy individuals may not apply to more susceptible populations whose further study is needed to avoid potentially misleading conclusions. In spite of limitations, the contributions of CHE-DE studies have greatly advanced current understanding of the health impacts associated with TRAP exposure, especially regarding mechanisms therein, with important implications for regulation and policy.

Lung function and self-rated symptoms in healthy volunteers after exposure to hydrotreated vegetable oil (HVO) exhaust with and without particles

Background

Diesel engine exhaust causes adverse health effects. Meanwhile, the impact of renewable diesel exhaust, such as hydrotreated vegetable oil (HVO), on human health is less known. Nineteen healthy volunteers were exposed to HVO exhaust for 3 h in a chamber with a double-blind, randomized setup. Exposure scenarios comprised of HVO exhaust from two modern non-road vehicles with 1) no aftertreatment system (‘HVO_PM+NOx’ PM1: 93 µg m⁻³, EC: 54 µg m⁻³, NO: 3.4 ppm, NO₂: 0.6 ppm), 2) an aftertreatment system containing a diesel oxidation catalyst and a diesel particulate filter (‘HVO_NOx’ PM1: ~ 1 µg m⁻³, NO: 2.0 ppm, NO₂: 0.7 ppm) and 3) filtered air (FA) as control. The exposure concentrations were in line with current EU occupational exposure limits (OELs) of NO, NO₂, formaldehyde, polycyclic aromatic hydrocarbons (PAHs), and the future OEL (2023) of elemental carbon (EC). The effect on nasal patency, pulmonary function, and self-rated symptoms were assessed. Calculated predicted lung deposition of HVO exhaust particles was compared to data from an earlier diesel exhaust study.

Results

The average total respiratory tract deposition of PM1 during HVO_PM+NOx was 27 µg h⁻¹. The estimated deposition fraction of HVO PM1 was 40–50% higher compared to diesel exhaust PM1 from an older vehicle (earlier study), due to smaller particle sizes of the HVO_PM+NOx exhaust. Compared to FA, exposure to HVO_PM+NOx and HVO_NOx caused higher incidence of self-reported symptoms (78%, 63%, respectively, vs. 28% for FA, p < 0.03). Especially, exposure to HVO_PM+NOx showed 40–50% higher eye and throat irritation symptoms. Compared to FA, a decrement in nasal patency was found for the HVO_NOx exposures (− 18.1, 95% CI: − 27.3 to − 8.8 L min⁻¹, p < 0.001), and for the HVO_PM+NOx (− 7.4 (− 15.6 to 0.8) L min⁻¹, p = 0.08). Overall, no clinically significant change was indicated in the pulmonary function tests (spirometry, peak expiratory flow, forced oscillation technique).

Conclusion

Short-term exposure to HVO exhaust concentrations corresponding to EU OELs for one workday did not cause adverse pulmonary function changes in healthy subjects. However, an increase in self-rated mild irritation symptoms, and mild decrease in nasal patency after both HVO exposures, may indicate irritative effects from exposure to HVO exhaust from modern non-road vehicles, with and without aftertreatment systems.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12989-021-00446-7.

Diesel particulate matter exposure deteriorates cardiovascular health and increases the sensitivity of rat heart towards ischemia reperfusion injury via suppressing mitochondrial bioenergetics function

Documents from previous studies do not sufficiently explain the pathophysiological alterations involved in rat hearts exposed to PM2.5 from diesel exhaust, termed as Diesel Particulate matter (DPM). In the present study, we explored the cardiovascular effect of DPM exposure on the recovery of heart from Ischemia reperfusion injury (IR) and explored the probable cause-effect relationship. Two groups of female Wistar rats were exposed to 0.5 mg/ml DPM for 1 h and 3 h durations daily for 21 days via a whole-body exposure system. At the end of 21st day, the animals were sacrificed and the heart was subjected to IR via Langendorff isolated rat heart perfusion system. 21 days of exposure altered cardiac electrophysiology and the ultra-structure of myocardium. Also, the same group of animals exhibited calcification in the vasculature. These changes were prominent in animals exposed to DPM for 3 h daily. Administration of DPM to H9C2 cells resulted in 15% and 36% cell death after 1hr and 3hrs of incubation, respectively. When the hearts were challenged to IR, both 1 h and 3 h exposed hearts exhibited a significant decline in IR recovery. At the sub-cellular level, DPM exposure reduced ATP levels, mitochondrial copy number, and increased oxidative stress after IR in both exposure groups. These changes were markedly seen in the interfibrillar mitochondrial fraction of the mitochondria. Hence, we conclude that exposure to PM2.5 from diesel exhaust alters electrophysiology and ultrastructure of heart and reduces the level of cellular mediators, thereby compromising the ability of heart to withstand IR injury.

Pulmonary translocation of ultrafine carbon particles in COPD and IPF patients

OBJECTIVE

Epidemiological studies indicate association between elevated air pollution and adverse health effects. Several mechanisms have been suggested, including translocation of inhaled ultrafine carbon (UFC) particles into the bloodstream. Previous studies in healthy subjects have shown no significant pulmonary translocation of UFC-particles. This study aimed to assess if UFC-particles translocate from damaged alveolar compartment in subjects suffering from chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF).

METHODS

Eleven COPD and nine IPF subjects were exposed to a 100 nm UFC-particle-aerosol labeled with Indium-111. Activity in the body was followed up for 10 days using gamma camera planar-imaging as well as in blood and urine samples.

RESULTS

The pulmonary central to periphery activity ratio was significantly higher for COPD as compared to IPF subjects at exposure, 1.8 and 1.4, respectively and remained constant throughout the test period. Ten days after exposure, the estimated median pulmonary translocation of UFC particles was 22.8 and 25.8% for COPD and IPF, respectively. Bound activity was present in blood throughout the test period, peaking at 24-h postinhalation with a median concentration of 5.6 and 8.9 Bq/ml for the COPD and IPF, respectively. Median bound activity excreted in urine (% of inhaled) after 10 days was 1.4% in COPD and 0.7% in IPF. Activity accumulation in liver and spleen could not be demonstrated.

CONCLUSIONS

Our results suggest that UFC particles leak through the damaged alveolar barrier to the bloodstream in COPD and IPF patients probably distributing in a wide spectrum of whole-body tissues.

Air pollution and recurrence of cardiovascular events after ST-segment elevation myocardial infarction

BACKGROUND AND AIMS

The effects of air pollution on discharged patients after ST-segment elevation myocardial infarction (STEMI) still remain uncertain. We examined the association between air pollutants and recurrent cardiovascular events in STEMI survivors.

METHODS

A retrospective cohort of 1641 discharged patients after STEMI was established in 2013 and followed until the end of 2019. Concentrations of air pollutants including fine particles <2.5 μm aerodynamic diameter (PM_2.5), inhalable particles <10 μm aerodynamic diameter (PM₁₀), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), carbon monoxide (CO) and ozone (O₃) measured by fixed ambient air monitoring stations were collected for exposure assessment. Multivariate-adjusted Cox proportional hazards models were used to estimate the increased risks of recurrent cardiovascular events.

RESULTS

Compared with the first exposure quartile, for short-term exposure, hazard ratios (HRs) of recurrent cardiovascular events associated with the fourth exposure quartiles of PM_2.5, PM₁₀, NO₂, SO₂, CO, and O₃ were 4.06 (95% CI: 2.62-6.30), 3.79 (95% CI: 2.57-5.58), 2.22 (95% CI: 1.67-2.94), 4.47 (95% CI: 3.08-6.48), 3.73 (95% CI: 2.54-5.48), and 5.35 (95% CI: 3.12-9.20), respectively. For long-term exposure, HRs associated with the fourth exposure quartiles of PM_2.5, PM₁₀, NO₂, SO₂, CO, and O₃ were 6.43 (95% CI: 3.60-11.47), 4.77 (95% CI: 2.85-7.99), 3.22 (95% CI: 2.00-5.19), 3.20 (95% CI: 2.05-5.01), 4.44 (95% CI: 2.65-7.45), and 1.07 (95% CI: 0.80-1.42), respectively. The risks of recurrent cardiovascular events brought by air pollutants mostly increased nonlinearly.

CONCLUSIONS

Short- and long-term exposure to air pollutants except ozone increases the risks of recurrent cardiovascular events in STEMI survivors. Better environmental policies and secondary prevention strategies should be developed to protect STEMI survivors as a susceptible population.

Environmental risk factors and cardiovascular diseases: a comprehensive review

Noncommunicable diseases (NCDs) are fatal for more than 38 million people each year and are thus the main contributors to the global burden of disease accounting for 70% of mortality. The majority of these deaths are caused by cardiovascular disease. The risk of NCDs is strongly associated with exposure to environmental stressors such as pollutants in the air, noise exposure, artificial light at night and climate change, including heat extremes, desert storms and wildfires. In addition to the traditional risk factors for cardiovascular disease such as diabetes, arterial hypertension, smoking, hypercholesterolemia and genetic predisposition, there is a growing body of evidence showing that physicochemical factors in the environment contribute significantly to the high NCD numbers. Furthermore, urbanization is associated with accumulation and intensification of these stressors. This comprehensive expert review will summarize the epidemiology and pathophysiology of environmental stressors with a focus on cardiovascular NCDs. We will also discuss solutions and mitigation measures to lower the impact of environmental risk factors with focus on cardiovascular disease.

The cardiovascular effects of air pollution: Prevention and reversal by pharmacological agents

Air pollution is associated with staggering levels of cardiovascular morbidity and mortality. Airborne particulate matter (PM), in particular, has been associated with a wide range of detrimental cardiovascular effects, including impaired vascular function, raised blood pressure, alterations in cardiac rhythm, blood clotting disorders, coronary artery disease, and stroke. Considerable headway has been made in elucidating the biological processes underlying these associations, revealing a labyrinth of multiple interacting mechanistic pathways. Several studies have used pharmacological agents to prevent or reverse the cardiovascular effects of PM; an approach that not only has the advantages of elucidating mechanisms, but also potentially revealing therapeutic agents that could benefit individuals that are especially susceptible to the effects of air pollution. This review gathers investigations with pharmacological agents, offering insight into the biology of how PM, and other air pollutants, may cause cardiovascular morbidity.

Ambient Air Pollution and Atherosclerosis: Recent Updates

Purpose of Review

During the past century, exposure to particulate matter (PM) air pollution < 2.5 μm in diameter (PM_2.5) has emerged as an all-pervading element of modern-day society. This increased exposure has come at the cost of heightened risk for cardiovascular (CV) morbidity and mortality. Not only can short-term PM_2.5 exposure trigger acute CV events in susceptible individuals, but longer-term exposure over years augments CV risk to a greater extent in comparison with short-term exposure. The purpose of this review is to examine the available evidence for how ambient air pollution exposure may precipitate events at various time frames.

Recent Findings

Recent epidemiological studies have demonstrated an association between ambient PM_2.5 exposure and the presence and progression of atherosclerosis in humans. Multiple animal exposure experiments over two decades have provided strong corroborative evidence that chronic exposure in fact does enhance the progression and perhaps vulnerability characteristics of atherosclerotic lesions.

Summary

Evidence from epidemiological studies including surrogates of atherosclerosis, human translational studies, and mechanistic investigations utilizing animal studies have improved our understanding of how ambient air pollution may potentiate atherosclerosis and precipitate cardiovascular events. Even so, future research is needed to fully understand the contribution of different constituents in ambient air pollution–mediated atherosclerosis as well as how other systems may modulate the impact of exposure including adaptive immunity and the gut microbiome. Nevertheless, due to the billions of people continually exposed to PM_2.5, the long-term pro-atherosclerotic effects of this ubiquitous air pollutant are likely to be of enormous and growing global public health importance.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11883-021-00958-9.

Oxidative Stress Biomarkers in the Relationship between Type 2 Diabetes and Air Pollution

The incidence and prevalence of type 2 diabetes have increased in the last decades and are expected to further grow in the coming years. Chronic hyperglycemia triggers free radical generation and causes increased oxidative stress, affecting a number of molecular mechanisms and cellular pathways, including the generation of advanced glycation end products, proinflammatory and procoagulant effects, induction of apoptosis, vascular smooth-muscle cell proliferation, endothelial and mitochondrial dysfunction, reduction of nitric oxide release, and activation of protein kinase C. Among type 2 diabetes determinants, many data have documented the adverse effects of environmental factors (e.g., air pollutants) through multiple exposure-induced mechanisms (e.g., systemic inflammation and oxidative stress, hypercoagulability, and endothelial and immune responses). Therefore, here we discuss the role of air pollution in oxidative stress-related damage to glycemic metabolism homeostasis, with a particular focus on its impact on health. In this context, the improvement of new advanced tools (e.g., omic techniques and the study of epigenetic changes) may provide a substantial contribution, helping in the evaluation of the individual in his biological totality, and offer a comprehensive assessment of the molecular, clinical, environmental, and epidemiological aspects.

Association Between Air Pollution and Acute Coronary Syndromes During Lockdown for COVID-19: Results From the Terni Hub Center

Background: During the lockdown for COVID-19, a massive decrease in hospital admissions for acute coronary syndrome (ACS) and a drop in air pollution were both detected in Italy. Our aim was to investigate the possible association between these two events at the Province of Terni, one of the most polluted urban and industrial area in Central Italy. Methods: We analyzed data of daily 24-h urban air concentrations of particulate matter (PM)10 and PM2.5 from fixed station monitoring network located in the main city centers of the Terni province, and accesses for ACS at the catheterization laboratory of the Cardiological Hub Center of the Terni University Hospital during lockdown. A comparison was made with data corresponding to the same lockdown time period of years 2019, 2018, and 2017. Results: Invasive procedures for ACS decreased in 2020 (n = 49) as compared with previous years (n = 93 in 2019, n = 109 in 2018, and n = 89 in 2017, p < 0.001). Conversely, reductions in average PM10 (20.7 μg/m³) and PM2.5 (14.7 μg/m³) in 2020 were consistent with a long-term decreasing trend, being comparable to those recorded in 2019 and 2018 (all p > 0.05) and slightly lower than 2017 (p < 0.05). The Granger-causality test demonstrated the lack of association between time-varying changes in air pollution and the number of procedures for ACS. Conclusions: Our results did not support the hypothesis that reduction in invasive procedures for ACS during lockdown was linked to an air cleaning effect. Reasons other than reduced air pollution should be sought to explain the observed decrease in ACS procedures.

Acute cardiovascular effects of controlled exposure to dilute Petrodiesel and biodiesel exhaust in healthy volunteers: a crossover study

BACKGROUND

Air pollution derived from combustion is associated with considerable cardiorespiratory morbidity and mortality in addition to environmental effects. Replacing petrodiesel with biodiesel may have ecological benefits, but impacts on human health remain unquantified. The objective was to compare acute cardiovascular effects of blended and pure biodiesel exhaust exposure against known adverse effects of petrodiesel exhaust (PDE) exposure in human subjects. In two randomized controlled double-blind crossover studies, healthy volunteers were exposed to PDE or biodiesel exhaust for one hour. In study one, 16 subjects were exposed, on separate occasions, to PDE and 30% rapeseed methyl ester biodiesel blend (RME30) exhaust, aiming at PM10 300 μg/m3. In study two, 19 male subjects were separately exposed to PDE and exhaust from a 100% RME fuel (RME100) using similar engine load and exhaust dilution. Generated exhaust was analyzed for physicochemical composition and oxidative potential. Following exposure, vascular endothelial function was assessed using forearm venous occlusion plethysmography and ex vivo thrombus formation was assessed using a Badimon chamber model of acute arterial injury. Biomarkers of inflammation, platelet activation and fibrinolysis were measured in the blood.

RESULTS

In study 1, PDE and RME30 exposures were at comparable PM levels (314 ± 27 μg/m3; (PM10 ± SD) and 309 ± 30 μg/m3 respectively), whereas in study 2, the PDE exposure concentrations remained similar (310 ± 34 μg/m3), but RME100 levels were lower in PM (165 ± 16 μg/m3) and PAHs, but higher in particle number concentration. Compared to PDE, PM from RME had less oxidative potential. Forearm infusion of the vasodilators acetylcholine, bradykinin, sodium nitroprusside and verapamil resulted in dose-dependent increases in blood flow after all exposures. Vasodilatation and ex vivo thrombus formation were similar following exposure to exhaust from petrodiesel and the two biodiesel formulations (RME30 and RME100). There were no significant differences in blood biomarkers or exhaled nitric oxide levels between exposures.

CONCLUSIONS

Despite differences in PM composition and particle reactivity, controlled exposure to biodiesel exhaust was associated with similar cardiovascular effects to PDE. We suggest that the potential adverse health effects of biodiesel fuel emissions should be taken into account when evaluating future fuel policies.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01337882 /NCT01883466. Date of first enrollment March 11, 2011, registered April 19, 2011, i.e. retrospectively registered.

Concentration-dependent health effects of air pollution in controlled human exposures

BACKGROUND

Air pollution is a leading contributor to premature mortality worldwide and is often represented by particulate matter (PM), a key contributor to its harmful health effects. Concentration-response relationships are useful for quantifying the effects of air pollution in relevant populations and in considering potential effect thresholds. Controlled human exposures can provide data on acute effects and concentration-response relationships that complement epidemiological studies.

OBJECTIVES

We examined PM concentration-responses after controlled human air pollution exposures to examine exposure-response markers, assess effect modifiers, and identify potential effect thresholds.

METHODS

We reviewed primary research from published controlled human exposure studies where responses were reported at multiple target PM concentrations or summarized per unit change in PM to identify concentration-dependent effects.

RESULTS

Of the 191 publications identified through PubMed and supplementary searches, 31 were eligible. Eligible studies collectively represented four pollutant models: concentrated ambient particles, engineered carbon nanoparticles, diesel exhaust, and woodsmoke. We identified concentration-dependent effects on oxidative stress markers, inflammation, and cardiovascular function that overlapped across different pollutants. Metabolic syndrome and glutathione s-transferase mu 1 genotype were identified as potential effect modifiers.

DISCUSSION

Improved understanding of concentration-response relationships is integral to biomonitoring and mitigation of health effects through impact assessment and policy. Although we identified potential concentration-response markers, thresholds, and modifiers, our conclusions on these relationships were limited by a dearth of eligible publications, considerable variability in methodology, and inconsistent reporting standards between studies. More research is required to validate these observations. We recommend that future studies harmonize estimate reporting to facilitate the identification of robust response markers across research and applied settings.