Exposure to fine particulate matter promotes platelet activation and thrombosis via obesity-related inflammation

Changes in cargoes of platelet derived extracellular vesicles heterogeneous subpopulations induced by PM0.1--Undisclosed cardiovascular injury communication mechanism

Epidemiological evidence has indicated a closely link between PM0.1 exposure and the incidence rate of cardiovascular diseases. This study explores the underlying communication roles of platelet-derived extracellular vesicles (PEVs) heterogeneous subpopulations in cardiovascular injury. PEVs and PMEVs which were extracted from platelet-rich plasma (PRP) un-exposure or exposure to PM0.1 by TIM4 affinity beads. By optimizing separation conditions, replacing pipelines, and resetting injection procedures, Asymmetric flow field-flow fractionation (AF4) was employed to separate, purify, characterize, and enrich PEVs and PMEVs heterogeneous subpopulations (small PEVs, PEVs-S/PMEVs-S: <100 nm; medium PEVs, PEVs-M/PMEVs-M: 100-200 nm; and large PEVs, PEVs-L/PMEVs-L: >200 nm). The results showed that the cargoes of PMEVs heterogeneous subpopulations which were released by PRP stimulated by PM0.1 were changed obviously. Moreover, compared with PEVs, PMEVs can lead to a decrease in the survival rate of Human Umbilical Vein Endothelial Cells (HUVECs). In PMEVs-S subpopulations, the alterations of lipids associated with membrane fusion and cell signaling transport (such as PC, Cer), as well as miRNAs related to inflammation, angiogenesis, and migration (miR-223, miR-22, miR-126, and miR-150), are similar to those in PMEVs-M subpopulations but distinct from PMEVs-L subpopulations. This study revealed the diverse communication mechanisms underlying PM0.1-induced cardiovascular injury, thereby offering potential avenues for the development of new biomarkers and therapeutic targets.

Effect of short-term exposure to air pollution on hospital admission for cardiovascular disease: A time-series study in Xiangyang, China

BACKGROUND

Data on the relationship between short-term exposure to air pollution and cardiovascular diseases (CVDs) and the potential modifying factors are limited and inconsistent.

OBJECTIVE

To explore the relationship between short-term exposure to air pollution and CVD risk, and potential modification effect factors.

METHOD

A time series study was conducted on 52,991 hospital admissions for CVD from 2015 to 2019 in Xiangyang City, China. Air pollution data from four national fixed monitoring stations were collected to estimate exposure level in Xiangyang City. A quasi-Poisson generalized additive model incorporating a distributed lag nonlinear model was applied to evaluate the association between air pollution and CVD risk. The potential modification effect of sex, age, and season on the above associations was also evaluated.

RESULTS

CVD risk was positively associated with air pollution. Peak associations in single lag day structures were observed for particulate matter ≤10 μm in aerodynamic (PM10; RR: 1.040, 95 % CI: 0.996-1.087), PM2.5 (1.025, 1.004-1.045), nitrogen dioxide (NO2; 1.074, 1.039-1.111), and sulfur dioxide (SO2; 1.079, 1.019-1.141) at Lag 0 and ozone (O3; 1.018, 1.004-1.031) at Lag 4. In cumulative lag day structures, the highest RRs were 1.225 (1.079,1.392) for PM10 at Lag 06, 1.054 (1.013, 1.098) for PM2.5 at Lag 03, 1.200 (1.119, 1.287) for NO2 at Lag 04, and 1.135 (1.025, 1.257) for SO2 at Lag 02. Moreover, the association between air pollution and CVD risk was modified by sex and age (P < 0.05). Females and individuals aged ≤65 years were more vulnerable to NO2 and had a higher CVD risk.

CONCLUSION

Short-term exposure to air pollution was positively associated with CVD risk. Moreover, sex and age could modify the effect of air pollution on CVD risk. Females and individuals aged ≤65 years had a higher NO2 exposure-induced CVD risk.

Association between Ambient Particulate Air Pollution and Soluble Biomarkers of Endothelial Function: A Meta-Analysis

BACKGROUND

The burden of cardiovascular diseases caused by ambient particulate air pollution is universal. An increasing number of studies have investigated the potential effects of exposure to particulate air pollution on endothelial function, which is one of the important mechanisms for the onset and development of cardiovascular disease. However, no previous study has conducted a summary analysis of the potential effects of particulate air pollution on endothelial function.

OBJECTIVES

To summarize the evidence for the potential effects of short-term exposure to ambient particulate air pollution on endothelial function based on existing studies.

METHODS

A systematic literature search on the relationship between ambient particulate air pollution and biomarkers of endothelial function including endothelin-1 (ET-1), E-selectin, intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) was conducted in PubMed, Scopus, EMBASE, and Web of Science up to 20 May 2023. Subsequently, a meta-analysis was conducted using a random effects model.

RESULTS

A total of 18 studies were included in this meta-analysis. A 10 μg/m3 increase in short-term exposure to ambient PM2.5 was associated with a 1.55% (95% CI: 0.89%, 2.22%) increase in ICAM-1 and a 1.97% (95% CI: 0.86%, 3.08%) increase in VCAM-1. The associations of ET-1 (0.22%, 95% CI: -4.94%, 5.65%) and E-selectin (3.21%, 95% CI: -0.90% 7.49%) with short-term exposure to ambient PM2.5 were statistically insignificant.

CONCLUSION

Short-term exposure to ambient PM2.5 pollution may significantly increase the levels of typical markers of endothelial function, including ICAM-1 and VCAM-1, suggesting potential endothelial dysfunction following ambient air pollution exposure.

Fine Particulate Matter Exposure, Genetic Susceptibility, and the Risk of Incident Stroke: A Prospective Cohort Study

BACKGROUND

Both genetic factors and environmental air pollution contribute to the risk of stroke. However, it is unknown whether the association between air pollution and stroke risk is influenced by the genetic susceptibilities of stroke and its risk factors.

METHODS

This prospective cohort study included 40 827 Chinese adults without stroke history. Satellite-based monthly fine particulate matter (PM2.5) estimation at 1-km resolution was used for exposure assessment. Based on 534 identified genetic variants from genome-wide association studies in East Asians, we constructed 6 polygenic risk scores for stroke and its risk factors, including atrial fibrillation, blood pressure, type 2 diabetes, body mass index, and triglyceride. The Cox proportional hazards model was applied to evaluate the hazard ratios and 95% CIs for the associations of PM2.5 and polygenic risk score with incident stroke and the potential effect modifications.

RESULTS

Over a median follow-up of 12.06 years, 3147 incident stroke cases were documented. Compared with the lowest quartile of PM2.5 exposure, the hazard ratio (95% CI) for stroke in the highest quartile group was 2.72 (2.42-3.06). Among individuals at high genetic risk, the relative risk of stroke was 57% (1.57; 1.40-1.76) higher than those at low genetic risk. Although no statistically significant interaction was found, participants with both the highest PM2.5 and high genetic risk showed the highest risk of stroke, with ≈4× that of the lowest PM2.5 and low genetic risk group (hazard ratio, 3.55 [95% CI, 2.84-4.44]). Similar upward gradients were observed in the risk of stroke when assessing the joint effects of PM2.5 and genetic risks of blood pressure, type 2 diabetes, body mass index, atrial fibrillation, and triglyceride.

CONCLUSIONS

Long-term exposure to PM2.5 was associated with a higher risk of incident stroke across different genetic susceptibilities. Our findings highlighted the great importance of comprehensive assessment of air pollution and genetic risk in the prevention of stroke.

Proteomic analysis reveals activation of platelet- and fibrosis-related pathways in hearts of ApoE-/- mice exposed to diesel exhaust particles

Air pollution is an environmental risk factor linked to multiple human diseases including cardiovascular diseases (CVDs). While particulate matter (PM) emitted by diesel exhaust damages multiple organ systems, heart disease is one of the most severe pathologies affected by PM. However, the in vivo effects of diesel exhaust particles (DEP) on the heart and the molecular mechanisms of DEP-induced heart dysfunction have not been investigated. In the current study, we attempted to identify the proteomic signatures of heart fibrosis caused by diesel exhaust particles (DEP) in CVDs-prone apolipoprotein E knockout (ApoE-/-) mice model using tandem mass tag (TMT)-based quantitative proteomic analysis. DEP exposure induced mild heart fibrosis in ApoE-/- mice compared with severe heart fibrosis in ApoE-/- mice that were treated with CVDs-inducing peptide, angiotensin II. TMT-based quantitative proteomic analysis of heart tissues between PBS- and DEP-treated ApoE-/- mice revealed significant upregulation of proteins associated with platelet activation and TGFβ-dependent pathways. Our data suggest that DEP exposure could induce heart fibrosis, potentially via platelet-related pathways and TGFβ induction, causing cardiac fibrosis and dysfunction.

Obesity-related cardiometabolic indicators modify the associations of personal noise exposure with heart rate variability: A further investigation on the Study among Obese and Normal-weight Adults (SONA)

Elucidating the associations between environmental noise and heart rate variability (HRV) would be beneficial for the prevention and control of detrimental cardiovascular changes. Obese people have been found to manifest heightened susceptibility to the adverse effects of noise on HRV. However, the underlying mechanisms remain unclear. Based on 53 normal-weight and 44 obese young adults aged 18-26 years in Beijing, China, this study aimed to investigate the role of obesity-related cardiometabolic indicators for associations between short-term environmental noise exposure and HRV in the real-world context. The participants underwent personal noise exposure and ambulatory electrocardiogram monitoring using portable devices at 5-min intervals for 24 continuous hours. Obesity-related blood pressure, glucose and lipid metabolism, and inflammatory indicators were subsequently examined. Generalized mixed-effect models were used to estimate the associations between noise exposure and HRV parameters. The C-peptide, homeostasis model assessment of insulin resistance (HOMA-IR), and leptin levels were higher in obese participants compared to normal-weight participants. We observed amplified associations between short-term noise exposure and decreases in HRV among participants with higher C-peptide, HOMA-IR, and leptin levels. For instance, a 1 dB(A) increment in 3 h-average noise exposure level preceding each measurement was associated with changes of -0.20% (95%CI: -0.45%, 0.04%) and -1.35% (95%CI: -1.85%, -0.86%) in standard deviation of all normal to normal intervals (SDNN) among participants with lower and higher C-peptide levels, respectively (P for interaction <0.05). Meanwhile, co-existing fine particulate matter (PM2.5) could amplify the associations between noise and HRV among obese participants and participants with higher C-peptide, HOMA-IR, and leptin levels. The more apparent associations of short-term exposure to environmental noise with HRV and the effect modification by PM2.5 may be partially explained by the higher C-peptide, HOMA-IR, and leptin levels of obese people.

The combined effects of exposure to multiple PM2.5 components on overweight and obesity in middle-aged and older adults: a nationwide cohort study from 125 cities in China

The prevalence of overweight or obesity increased rapidly over the past decades in most countries, including China. However, little evidence exists about the effects of long-term exposure to PM2.5 components on overweight or obesity, particularly in developing countries. We measured different weight stages according to body mass index (BMI), and investigated the effects of exposure to PM2.5 components (ammonium [[Formula: see text]], sulfate [[Formula: see text]], nitrate [[Formula: see text]], black carbon and organic matter) on different BMI levels in middle-aged and elderly people of China. Our study explored the effects of single and multiple air pollution exposures on overweight and obesity by using the Generalized Linear Model and Quantile g-Computation model (QgC). This study found a significantly positive association between five PM2.5 components and overweight/obesity. In the QgC model, there was still a positive association between multiple exposure to PM2.5 components and overweight when all PM2.5 components were considered as a whole. In addition, males, the elderly, and urban residents were also more sensitive to five PM2.5 components.

Associations of Long-Term Exposure to PM2.5 and Its Constituents with Erythrocytosis and Thrombocytosis in Rural Populations

Evidence on the effect of long-term exposure to fine particulate matter (PM2.5) on erythrocytosis and thrombocytosis prevalence was limited. We aimed to investigate the association of PM2.5 and its constituents with the risks of erythrocytosis and thrombocytosis. The present study included a total of 33,585 participants from the Henan Rural Cohort at baseline between 2015 and 2017. A hybrid satellite-based model was employed to estimate the concentrations of PM2.5 mass and its constituents (including black carbon [BC], nitrate [NO3-], ammonium [NH4+], inorganic sulfate [SO42-], organic matter [OM], and soil particles [SOIL]). The logistic regression model was used to assess the associations of single exposure to PM2.5 and its constituents with the risks of erythrocytosis and thrombocytosis, and the quantile G-computation method was applied to evaluate their joint exposure risk. For the independent association, the odds ratios for erythrocytosis/thrombocytosis with 1 μg/m3 increase was 1.049/1.043 for PM2.5 mass, 1.596/1.610 for BC, 1.410/1.231 for NH4+, 1.205/1.139 for NO3-, 1.221/1.359 for OM, 1.300/1.143 for SO42-, and 1.197/1.313 for SOIL. Joint exposure to PM2.5 and its components was also positively associated with erythrocytosis and thrombocytosis. The estimated weight of NH4+ was found to be the largest for erythrocytosis, while OM had the largest weight for thrombocytosis. PM2.5 mass and its constituents were positively linked to prevalent erythrocytosis and thrombocytosis, both in single-exposure and joint-exposure models. Additionally, NH4+/OM was identified as a potentially responsible component for the association between PM2.5 and erythrocytosis/thrombocytosis.

Long non-coding RNAs mediate the association between short-term PM2.5 exposure and circulating biomarkers of systemic inflammation

Although short-term fine particulate matter (PM2.5) exposure is associated with systemic inflammation, the effect of lncRNA on these association remains unknown. This study aims to investigate whether the plasma lncRNA mediate the effect of short-term PM2.5 exposure on systemic inflammation. In this cross-sectional study, plasma Clara cell protein 16 (CC16), interleukin 6 (IL-6), IL-8, tumor necrosis factor-α (TNF-α) and lncRNA expression levels were measured in 161 adults between March and April in 2018 in Shijiazhuang, China. PM2.5 concentrations were estimated 0-3 days prior to the examination date and the moving averages were calculated. Multiple linear regressions were used to evaluate the associations between PM2.5, the four biomarkers and lncRNA expression levels. Mediation analyses were performed to explore the potential roles of lncRNA expression in these associations. The median concentration of PM2.5 ranged from 39.65 to 60.91 mg/m3 across different lag days. The most significant effects on IL-6 and TNF-α per interquartile range increase in PM2.5 were observed at lag 0-3 days, with increases of 0.70 pg/mL (95% CI: 0.33, 1.07) and 0.21 pg/mL (95% CI: 0.06, 0.36), respectively. While the associations between PM2.5 and IL-8 (0.68 pg/mL, 95% CI: 0.34, 1.02) and CC16 (3.86 ng/mL, 95% CI: 1.60, 6.13) were stronger at lag 0 day. Interestingly, a negative association between PM2.5 and the expression of four novel lncRNAs (lnc-ACAD11-1:1, lnc-PRICKLE1-4:1, lnc-GPR39-7:2, and lnc-MTRNR2L12-3:6) were observed at each lag days. Furthermore, these lncRNAs mediated the effects of PM2.5 on the four biomarkers, with proportions of mediation ranged from 2.27% (95% CI: 1.19%, 9.82%) for CC16 to 35.60% (95% CI: 17.16%, 175.45%) for IL-6. Our findings suggested that plasma lncRNA expression mediat the acute effects of PM2.5 exposure on systematic inflammation. These highlight a need to consider circulating lncRNA expression as biomarkers to reduce health risks associated with PM2.5.

Long-term exposures to ambient particulate matter and ozone pollution with lower extremity deep vein thrombosis after surgical operations: a retrospective case-control study in Beijing, China

BACKGROUND

Lower extremity deep vein thrombosis (LEDVT) after surgical operations is a common and fatal disease leading to unfavorable outcomes including death. Nevertheless, there has been insufficient evidence on the associations between ambient air pollution and LEDVT, particularly studies from developing regions.

METHODS

Based on 302 LEDVT cases and 302 controls in a general hospital in Beijing, China, this unmatched retrospective case-control study investigated the associations of fine particulate matter (PM2.5), inhalable particulate matter (PM10), and ozone (O3) with odds of LEDVT.

RESULTS

Per 10 μg/m3 increase in PM2.5, PM10, and O3 at 3-month, 6-month, and 2-year average was associated with increased LEDVT odds [odds ratios (ORs) for PM2.5: 1.10 (95%CI: 1.05, 1.14), 1.14 (95%CI: 1.09, 1.18), and 1.30 (95%CI: 1.06, 1.61); ORs for PM10: 1.06 (95%CI: 1.02, 1.10), 1.12 (95%CI: 1.08, 1.16), and 1.29 (95%CI: 1.03, 1.61); ORs for O3: 1.00 (95%CI: 0.96, 1.04), 1.16 (95%CI: 1.02, 1.31), and 2.08 (95%CI: 1.03, 4.18), respectively]. The stratified analyses, exposure-responses curves, and sensitivity analyses further highlighted the robustness of our findings.

CONCLUSIONS

Long-term exposures to ambient PM2.5, PM10, and O3 may increase the risk of LEDVT in patients after surgical operations. The results may be implicated in the prevention and control of adverse clinical outcomes of surgical patients associated with ambient air pollution.

PM2.5 induces alterations in gene expression profile of platelet-derived extracellular vesicles and mediates cardiovascular injury in rats

Platelet-derived extracellular vesicles (P-EVs), as the most abundant vesicles in blood, have been proven to play cardinal roles in cardiovascular injury. RNAs (especially miRNAs) carried by P-EVs can be transferred to the receptor, which plays a critical role in regulating vascular endothelial function. PM2.5 is one of the most well-known risk factors that cause cardiovascular disease. Therefore, the objective of the current study was to explore whether exposure to PM2.5 would alter the gene expression profile of P-EVs, and to further elucidate the role of RNAs (especially miRNAs) carried by P-EVs in cardiovascular injury induced by PM2.5 exposure. P-EVs were isolated from the platelet-rich plasma which was exposed and unexposed to PM2.5, and the differentially expressed target genes were evaluated using whole-transcriptome gene sequencing. Rats were treated with P-EVs under different exposure conditions (a protein concentration of 50 µg/mL) and an equal volume of normal saline. The pathological damage of the thoracic aorta and cardiac tissue was evaluated and the coagulation function of the rats was detected. The differentially expressed genes were shown to be mainly concentrated in inflammation, angiogenesis, and apoptosis-related pathways. Moreover, P-EVs extracted from PM2.5-exposed plasma had the potential to trigger an inflammatory response, impair vascular endothelial function, disrupt the normal coagulation process, and promote a prothrombotic state. Our study indicated that PM2.5 induces cardiovascular injury in rats by interfering with the gene expression of P-EVs. It will provide new targets for studying the mechanism involved in PM2.5-induced cardiovascular injury.

Fine particulate matter induces adipose tissue expansion and weight gain: Pathophysiology

Dysregulations in energy balance represent a major driver of obesity. Recent evidence suggests that environmental factors also play a pivotal role in inducing weight gain. Chronic exposure to fine particulate matter (PM_2.5 ) is associated with white adipose tissue (WAT) expansion in animals and higher rates of obesity in humans. This review discusses metabolic adaptions in central and peripheral tissues that promote energy storage and WAT accumulation in PM_2.5 -exposed animals and humans. Chronic PM_2.5 exposure produces inflammation and leptin resistance in the hypothalamus, decreasing energy expenditure and increasing food intake. PM_2.5 promotes the conversion of brown adipocytes toward the white phenotype, resulting in decreased energy expenditure. The development of inflammation in WAT can stimulate adipogenesis and hampers catecholamine-induced lipolysis. PM_2.5 exposure affects the thyroid, reducing the release of thyroxine and tetraiodothyronine. In addition, PM_2.5 exposure compromises skeletal muscle fitness by inhibiting Nitric oxide (NO)-dependent microvessel dilation and impairing mitochondrial oxidative capacity, with negative effects on energy expenditure. This evidence suggests that pathological alterations in the hypothalamus, brown adipose tissue, WAT, thyroid, and skeletal muscle can alter energy homeostasis, increasing lipid storage and weight gain in PM_2.5 -exposed animals and humans. Further studies will enrich this pathophysiological model.

How does particulate air pollution affect barrier functions and inflammatory activity of lung vascular endothelium?

Both particulate matter and gaseous components of air pollution have already been shown to increase cardiovascular mortality in numerous studies. It is, however, important to note that on their way to the bloodstream the polluting agents pass the lung barrier. Inside the alveoli, particles of approximately 0.4-1 μm are most efficiently deposited and commonly undergo phagocytosis by lung macrophages. Not only the soluble agents, but also particles fine enough to leave the alveoli enter the bloodstream in this finite part of the endothelium, reaching thus higher concentrations in close proximity of the alveoli and endothelium. Additionally, deposits of particulate matter linger in direct proximity of the endothelial cells and may induce inflammation, immune responses, and influence endothelial barrier dysfunction thus increasing PM bioavailability in positive feedback. The presented discussion provides an overview of possible components of indoor PM and how endothelium is thus influenced, with emphasis on lung vascular endothelium and clinical perspectives.

Joint effect of multiple air pollutants on cardiometabolic health in normal-weight and obese adults: A novel insight into the role of circulating free fatty acids

The cardiometabolic effects of air pollution in the context of mixtures and the underlying mechanisms remain not fully understood. This study aims to investigate the joint effect of air pollutant mixtures on a broad range of cardiometabolic parameters, examine the susceptibility of obese individuals, and determine the role of circulating fatty acids. In this panel study, metabolically healthy normal-weight (MH-NW, n = 49) and obese (MHO, n = 39) adults completed three longitudinal visits (257 person-visits in total). Personal exposure levels of PM_2.5, PM₁₀, O₃, NO₂, SO₂, CO and BC were estimated based on fixed-site monitoring data, time-activity logs and infiltration factor method. Blood pressure, glycemic homeostasis, lipid profiles, systematic inflammation and coagulation biomarkers were measured. Targeted metabolomics was used to quantify twenty-eight plasma free fatty acids (FFAs). Bayesian kernel machine regression models were applied to establish the exposure-response relationships and identify key pollutants. Significant joint effects of measured air pollutants on systematic inflammation and coagulation biomarkers were observed in the MHO group, instead of the MH-NW group. Lipid profiles showed the most significant changes in both groups and O₃ contributed the most to the total effect. Specific FFA patterns were identified, and de novo lipogenesis (DNL)-related pattern was most closely related to blood lipid profiles. In particular, interaction analysis suggested that DNL-related FFA pattern augmented the effects of O₃ on triglyceride (TG, P_interaction = 0.040), high-density lipoprotein cholesterol (HDL-C, P_interaction = 0.106) and TG/HDL-C (P_interaction = 0.020) in the MHO group but not MH-NW group. This modification was further confirmed by interaction analysis with estimated activity of SCD1, a key enzyme in the DNL pathway. Therefore, despite being metabolically healthy, obese subjects have a higher cardiometabolic susceptibility to air pollution, especially O₃, and the DNL pathway may represent an intrinsic driver of lipid susceptibility. This study provides new insights into the cardiometabolic susceptibility of obese individuals to air pollution.

Potential Biological Mediators of Myocardial and Vascular Complications of Air Pollution-A State-of-the-Art Review

Ambient air pollution is recognised globally as a significant contributor to the burden of cardiovascular diseases. The evidence from both human and animal studies supporting the cardiovascular impact of exposure to air pollution has grown substantially, implicating numerous pathophysiological pathways and related signalling mediators. In this review, we summarise the list of activated mediators for each pathway that lead to myocardial and vascular injury in response to air pollutants. We performed a systematic search of multiple databases, including articles between 1990 and Jan 2022, summarising the evidence for activated pathways in response to each significant air pollutant. Particulate matter <2.5 μm (PM_2.5) was the most studied pollutant, followed by particulate matter between 2.5 μm-10 μm (PM₁₀), nitrogen dioxide (NO₂) and ozone (O₃). Key pathogenic pathways that emerged included activation of systemic and local inflammation, oxidative stress, endothelial dysfunction, and autonomic dysfunction. We looked at how potential mediators of each of these pathways were linked to both cardiovascular disease and air pollution and included the overlapping mediators. This review illustrates the complex relationship between air pollution and cardiovascular diseases, and discusses challenges in moving beyond associations, towards understanding causal contributions of specific pathways and markers that may inform us regarding an individual's exposure, response, and likely risk.

Moderate physical activity against effects of short-term PM2.5 exposure on BP via myokines-induced inflammation

Exposure to PM2.5 increases blood pressure (BP) and cardiovascular morbidity and mortality. We conducted a randomized controlled panel study in Shijiazhuang, China among 55 healthy college students randomly assigned to either the control (CON) or SPORTS group with intervention of 2000 m jogging in 20 min for 3 times in 4 days, and 3-round health examinations from November 15, 2020 to December 6, 2020. We aimed to evaluate whether moderate physical activity (PA) protected BP health against PM2.5 exposure and explore potential mechanisms through myokines and inflammation. Individual PM2.5 exposure was calculated based on outdoor and indoor PM2.5 concentration monitoring data as well as time-activity diary of each subject. In the CON group, the exposure-response curve for SBP was linear with a threshold concentration of approximately 31 μg/m3, while an increment of SBP level was 4.38 mm Hg (95%CI: 0.17 mm Hg, 8.59 mm Hg) at lag03 for each 10-μg/m3 increase in PM2.5, using linear mixed-effect models. For inflammatory indicators, PM2.5 exposure was associated with significant increases in eosinophil counts and proportion in CON group, but decreases in MCP-1 and TNF-α in SPORTS group. Meanwhile, higher myokines including CLU and IL-6 were observed in SPORTS group compared to the CON group. Further mediation analyses revealed that eosinophil counts mediated the elevated BP in CON group, whereas MCP-1 and TNF-α were also crucial mediating cytokines for the SPORTS group, as well as CLU and IL-6 acted as mediators on BP and inflammation indicators in SPORTS group. This study suggests that moderate PA could counteract the elevated BP induced by PM2.5 exposure via myokines-suppressed inflammation pathways.

Association between short-term exposure to ambient air pollution and biomarkers of coagulation: A systematic review and meta-analysis

Ambient air pollution is one of the major global risk factors for cardiovascular health, and coagulation changes have been proposed to mediate this risk. Plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor (vWF), soluble P-selectin (sP-selectin) and tissue plasminogen activator (t-PA) are major coagulation biomarkers. However, there has been no systematic meta-analysis to summarize associations of ambient air pollution with these coagulation biomarkers. To assess the overall associations between ambient particulate matter (PM_2.5, PM₁₀), ozone (O₃), nitrogen dioxide (NO₂), carbon monoxide (CO) and major coagulation biomarkers including PAI-1, vWF, sP-selectin and t-PA based on the existing epidemiological research. We performed a systematic literature search of publications reporting the associations of ambient air pollutants (PM_2.5, PM₁₀, O₃, NO_2, and CO) with coagulation biomarkers (PAI-1, vWF, sP-selectin and t-PA) in PubMed, Web of Science, EMBASE, and Scopus databases as of April 5, 2022. Then, we performed a random-effect meta-analysis, which included 27 articles, and then identified the potential sources of heterogeneity. The pooled percent changes of coagulation biomarkers per 10 μg/m³ increase in short-term exposure to ambient PM_2.5 were 2.43% (95% CI: 0.59%, 4.29%) in PAI-1, 1.08% (95% CI: 0.21%, 1.96%) in vWF and 1.14% (95% CI: 0.59%, 1.68%) in sP-selectin, respectively. We also found significant associations of short-term exposure to ambient O₃ with PAI-1 (1.62%, 95% CI: 0.01%, 3.25%), sP-selectin (9.59%, 95% CI:2.78%, 16.86%) and t-PA (0.45%, 95% CI: 0.02%, 0.88%), respectively. Short-term exposures to ambient PM₁₀, NO₂ and CO were not significantly associated with changes in coagulation biomarkers. In conclusion, short-term exposures to PM_2.5 and O₃ are associated with significant increases in coagulation biomarkers, suggesting an activated coagulation state upon air pollution exposure.

Associations of forest negative air ions exposure with cardiac autonomic nervous function and the related metabolic linkages: A repeated-measure panel study

Forest environment has many health benefits, and negative air ions (NAI) is one of the major forest environmental factors. Many studies have explored the effect of forest environment on cardiac autonomic nervous function, while forest NAI in the among function and the underlying mechanism still remain unclear. To explore the associations and molecular linkages between short-term exposure to forest NAI and heart rate variability (HRV), a repeated-measure panel study was conducted among 31 healthy adults. Participants were randomly selected to stay in a forest park for 3 days and 2 nights. Individual exposures including NAI were monitored simultaneously and HRV indices were measured repeatedly at the follow-up period. Urine samples were collected for non-targeted metabolomics analysis. Mixed-effect models were adopted to evaluate associations among NAI, HRV indices and metabolites. The median of NAI concentration was 68.11 (138.20) cm^-3 during the study period. Short-term exposure to forest NAI was associated with the ameliorative HRV indices, especially the excitatory parasympathetic nerve. For instance, per interquartile range increase of 5-min moving average of NAI was associated with 9.99 % (95%CI: 8.95 %, 11.03 %) increase of power in high frequency. Eight metabolites were associated with NAI exposure. The down-regulated tyrosine metabolism was firstly observed, followed by other amino acid metabolic alterations. The NAI-related metabolic changes reflect the reduction of inflammation and oxidative stress. HRV indices were associated with 25 metabolites, mainly including arginine, proline and histidine metabolism. Short-term exposure to forest NAI is beneficial to HRV, especially to the parasympathetic nerve activity, by successively disturbing different metabolic pathways which mainly reflect the increased anti-inflammation and the reduced inflammation. The results will provide epidemiological evidences for developing forest therapy and improving cardiac autonomic nervous function.

A comprehensive understanding of ambient particulate matter and its components on the adverse health effects based from epidemiological and laboratory evidence

The impacts of air pollution on public health have become a great concern worldwide. Ambient particulate matter (PM) is a major air pollution that comprises a heterogeneous mixture of different particle sizes and chemical components. The chemical composition and physicochemical properties of PM change with space and time, which may cause different impairments. However, the mechanisms of the adverse effects of PM on various systems have not been fully elucidated and systematically integrated. The Adverse Outcome Pathway (AOP) framework was used to comprehensively illustrate the molecular mechanism of adverse effects of PM and its components, so as to clarify the causal mechanistic relationships of PM-triggered toxicity on various systems. The main conclusions and new insights of the correlation between public health and PM were discussed, especially at low concentrations, which points out the direction for further research in the future. With the deepening of the study on its toxicity mechanism, it was found that PM can still induce adverse health effects with low-dose exposure. And the recommended Air Quality Guideline level of PM_2.5 was adjusted to 5 μg/m³ by World Health Organization, which meant that deeper and more complex mechanisms needed to be explored. Traditionally, oxidative stress, inflammation, autophagy and apoptosis were considered the main mechanisms of harmful effects of PM. However, recent studies have identified several emerging mechanisms involved in the toxicity of PM, including pyroptosis, ferroptosis and epigenetic modifications. This review summarized the comprehensive evidence on the health effects of PM and the chemical components of it, as well as the combined toxicity of PM with other air pollutants. Based on the AOP Wiki and the mechanisms of PM-induced toxicity at different levels, we first constructed the PM-related AOP frameworks on various systems.

Overview of particulate air pollution and human health in China: Evidence, challenges, and opportunities

Ambient particulate matter (PM) pollution in China continues to be a major public health challenge. With the release of the new WHO air quality guidelines in 2021, there is an urgent need for China to contemplate a revision of air quality standards (AQS). In the recent decade, there has been an increase in epidemiological studies on PM in China. A comprehensive evaluation of such epidemiological evidence among the Chinese population is central for revision of the AQS in China and in other developing countries with similar air pollution problems. We thus conducted a systematic review on the epidemiological literature of PM published in the recent decade. In summary, we identified the following: (1) short-term and long-term PM exposure increase mortality and morbidity risk without a discernible threshold, suggesting the necessity for continuous improvement in air quality; (2) the magnitude of long-term associations with mortality observed in China are comparable with those in developed countries, whereas the magnitude of short-term associations are appreciably smaller; (3) governmental clean air policies and personalized mitigation measures are potentially effective in protecting public and individual health, but need to be validated using mortality or morbidity outcomes; (4) particles of smaller size range and those originating from fossil fuel combustion appear to show larger relative health risks; and (5) molecular epidemiological studies provide evidence for the biological plausibility and mechanisms underlying the hazardous effects of PM. This updated review may serve as an epidemiological basis for China’s AQS revision and proposes several perspectives in designing future health studies.

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Acute effects of PM are smaller in China compared with developed countries

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Health effects caused by PM depend on particle composition, source, and size

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There are no thresholds for the health effects of PM

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Mechanistic studies support the biological plausibility of PM’s health effects

PM2.5-induced adipose tissue dysfunction can trigger metabolic disturbances

Exposure to particulate matter ≤2.5 μm in diameter (PM_2.5) alters cardiometabolic homeostasis. The reduced oxidative capacity in brown adipocytes and the development of inflammation and insulin resistance in white adipose tissue (WAT) can account for the dysmetabolic setting on PM_2.5 exposure. In this forum article, we discuss relevant evidence to highlight a causal connection between PM_2.5-induced adipose tissue dysfunction and cardiometabolic disturbances.

Associations between personal noise exposure and heart rate variability were modified by obesity and PM2.5: The study among obese and normal-weight adults (SONA)

Noise pollution has been documented to increase the risks of cardiovascular disorders, which can be predicted by heart rate variability (HRV), nevertheless, there has been limited evidence on the modifiers of noise pollution. Environmental fine particulate matter (PM_2.5) and obesity status are both growing major concerns of cardiovascular disease burden. Our study aims to investigate whether these two factors may modify the associations between noise exposure and HRV indices. An investigation was performed on 97 (53 normal-weight and 44 obese) participants aged 18-26 years, with continuous 5-min personal exposure assessment and ambulatory electrocardiogram monitoring for 24 h. This study found that personal exposure to noise was associated with decreased HRV level and imbalanced cardiac autonomic function, as indicated by decreases in standard deviation of normal-to-normal intervals (SDNN), square root of the mean squared differences of successive intervals (rMSSD), the percentage of R-R intervals that differ from each other by more than 50 ms (pNN50), low-frequency (LF) power, high-frequency (HF) power, and increases in LF-HF-Ratio. Stronger associations between personal noise exposure and HRV indices were observed among obese participants and participants with higher PM_2.5 exposure levels compared to their counterparts. For SDNN, a 1 dB(A) increment in personal noise exposure at 3h-average was associated with a 1.25% (95%CI: -1.64%, -0.86%) decrease among obese participants, and a 0.11% (95%CI: -0.38%, 0.16%) decrease among normal-weight participants (P for subgroup difference<0.001); and a 0.87% (95%CI: -1.20%, -0.54%) decrease among participants with higher PM_2.5 exposure levels, and a 0.22% (95%CI: -0.58%, 0.14%) decrease among participants with lower PM_2.5 exposure levels (P for subgroup difference = 0.008). Obesity and PM_2.5 may aggravate the adverse effects of noise on HRV, which has implications for targeted prevention of cardiovascular disease burden associated with noise pollution.

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 underlying mechanism of PM2.5-induced ischemic stroke

Under the background of global industrialization, PM_2.5 has become the fourth-leading risk factor for ischemic stroke worldwide, according to the 2019 GBD estimates. This highlights the hazards of PM_2.5 for ischemic stroke, but unfortunately, PM_2.5 has not received the attention that matches its harmfulness. This article is the first to systematically describe the molecular biological mechanism of PM_2.5-induced ischemic stroke, and also propose potential therapeutic and intervention strategies. We highlight the effect of PM_2.5 on traditional cerebrovascular risk factors (hypertension, hyperglycemia, dyslipidemia, atrial fibrillation), which were easily overlooked in previous studies. Additionally, the effects of PM_2.5 on platelet parameters, megakaryocytes activation, platelet methylation, and PM_2.5-induced oxidative stress, local RAS activation, and miRNA alterations in endothelial cells have also been described. Finally, PM_2.5-induced ischemic brain pathological injury and microglia-dominated neuroinflammation are discussed. Our ultimate goal is to raise the public awareness of the harm of PM_2.5 to ischemic stroke, and to provide a certain level of health guidance for stroke-susceptible populations, as well as point out some interesting ideas and directions for future clinical and basic research.

Co-exposure to multiple air pollutants and sleep disordered breathing in patients with or without obstructive sleep apnea: A cross-sectional study

BACKGROUND

Air pollution may be a contributing risk factor for obstructive sleep apnea (OSA). However, the health effects of co-exposure to multiple air pollutants on OSA patients remain unclear.

OBJECTIVES

To assess the joint effect of multi-pollutant on sleep disordered breathing (SDB) parameters in patients with or without OSA and identify the dominant pollutants.

METHODS

A total of 2524 outpatients from April 2020 to May 2021 were recruited in this cross-sectional study. Ambient air pollutant data were obtained from the nearest central monitoring stations to participants' residential address. SDB parameters were measured by the ApneaLink devices, including apnea-hypopnea index (AHI), hypopnea index (HI), oxygen desaturation index (ODI), average oxygen saturation (SpO₂), percentage sleep time with <90% saturation (T90), and desaturation. Bayesian kernel machine regression (BKMR) was applied to evaluate the effects of multiple pollutants.

RESULTS

Significant associations were observed between air pollutants and SDB parameters (including increases in AHI, HI, ODI, and desaturation) among patients with OSA. Co-exposure to air pollutants was positively correlated with AHI, HI, and ODI. PM₁₀ and O₃ dominated the effects of pollutant mixtures on OSA, with the highest posterior inclusion probability (PIP) values of 0.592 and 0.640, respectively. Stratified analysis showed that, compared to male patients with OSA, stronger effects on the SDB parameters were observed in female patients. Stronger associations were also found in the warm season than those in the cold season.

CONCLUSION

Co-exposure to air pollutants was associated with SDB parameters among patients with OSA, PM₁₀ and O₃ might play the dominant roles.

Ambient particulate air pollution, blood cell parameters, and effect modification by psychosocial stress: Findings from two studies in three major Chinese cities

The associations between particulate matter (PM) exposure, psychosocial stress and blood cell parameters are bringing novel insights to characterize the early damage of multiple diseases. Based on two studies conducted in three Chinses cities using cross-sectional (Beijing, 425 participants) and panel study (Tianjin and Shanghai, 92 participants with 361 repeated measurements) designs, this study explored the associations between short-term exposure to ambient PM and blood cell parameters, and the effect modification by psychosocial stress. Increasing PM_2.5 exposure was significantly associated with decreases in red blood cell (RBC) count and mean corpuscular hemoglobin concentration (MCHC), and increases in mean corpuscular volume (MCV), platelets count (PLT) and platelet hematocrit (PCT) in both studies. For instance, a 10 μg/m³ increment in PM_2.5 concentration was associated with a 1.04% (95%CI: 0.16%, 1.92%) increase in PLT (4-d) and a 1.09% (95%CI: 0.31%, 1.87%) increase in PCT (4-d) in the cross-sectional study, and a 0.64% (95%CI: 0.06%, 1.22%) increase in PLT (1-d) and a 0.72% (95%CI: 0.33%, 1.11%) increase in PCT (1-d) in the panel study, respectively. In addition, stronger increases in MCV, PLT, and PCT associated with PM_2.5 exposure were found in higher psychosocial stress group compared to lower psychosocial stress group (p for interaction <0.10), indicating that blood cell parameters of individuals with higher psychosocial stress might be more susceptible to the early damages of PM_2.5 exposure.

Short-term ozone exposure and metabolic status in metabolically healthy obese and normal-weight young adults: A viewpoint of inflammatory pathways

Unhealthy metabolic status increases risks of cardiovascular and other diseases. This study aims to explore whether there is a link between O₃ and metabolic health indicators through a viewpoint of inflammatory pathways. 49 metabolically healthy normal-weight (MH-NW) and 39 metabolically healthy obese (MHO) young adults aged 18-26 years were recruited from a panel study with three visits. O₃ exposure were estimated based on fixed-site environmental monitoring data and time-activity diary for each participant. Compared to MH-NW people, MHO people were more susceptible to the adverse effects on metabolic status, including blood pressure, glucose, and lipid indicators when exposed to O₃. For instance, O₃ exposure was associated with significant decreases in high-density lipoprotein cholesterol (HDL-C), and increases in C-peptide and low-density lipoprotein cholesterol (LDL-C) among MHO people, while only weaker changes in HDL-C and LDL-C among MH-NW people. Mediation analyses indicated that leptin mediated the metabolic health effects in both groups, while eosinophils and MCP-1 were also important mediating factors for the MHO people. Although both with a metabolically healthy status, compared to normal-weight people, obese people might be more susceptible to the negative effects of O₃ on metabolic status, possibly through inflammatory indicators such as leptin, eosinophils, and MCP-1.

Intermittent exposure to airborne particulate matter induces subcellular dysfunction and aortic cell damage in BALB/c mice through multi-endpoint assessment at environmentally relevant concentrations

Airborne particulate matter (PM) has been linked to cardiovascular diseases, but the underlying mechanisms remain unclear, especially at realistic exposure levels. In this study, both male and female BALB/c mice were employed to assess vascular homeostasis following a standard urban particulate matter, PM SRM1648a, via oropharyngeal aspiration at three environmentally relevant concentrations. The tested indicators included histopathological observation and lipid deposition, as well as redox biology and inflammatory responses. Furthermore, endothelial monolayer, vascular cell apoptosis and subcellular function were assessed to decipher whether episodic PM SRM1648a exposure leads to vascular damage after multiple periods of treatment, including subacute (4 weeks) and subchronic (8 weeks) durations. As a result, PM aspiration caused thickening of airways, leukocytes infiltration and adhesion to alveoli, with the spot of particles engulfed by pulmonary macrophages. Meanwhile, it induced local and systemic oxidative stress and inflammation, but limited pathological changes were captured throughout aortic tissues after either subacute or subchronic treatment. Furthermore, even in the absence of aortic impairment, vascular cell equilibrium has been disturbed by the characteristics of endothelial monolayer disintegration and cell apoptosis. Mechanistically, PM SRM1648a activated molecular markers of ER stress (BIP) and mitochondrial dynamics (DRP1) at both transcriptional and translational levels, which were strongly correlated to ox-inflammation and could serve as early checkpoints of hazardous events. In summary, our data basically indicate that episodic exposure of BALB/c mice to PM SRM1648a exerts limited effects on vascular histopathological alterations, but induces vascular cell apoptosis and subcellular dysfunction, to which local and systemic redox biology and inflammation are probably correlated.

Melatonin protects against PM2.5-induced lung injury by inhibiting ferroptosis of lung epithelial cells in a Nrf2-dependent manner

PM2.5 refers to ambient air particulate matter with aerodynamic diameters ≤ 2.5 µm, which has been a global environmental problem threatening public health in recent years. Melatonin serving as one of the predominant hormones secreted by the pineal gland displays multiple pharmacological properties in various diseases. However, little is known about the possible effects of melatonin in the development of lung injury induced by PM2.5. This study was designed to explore the potential roles of melatonin as well as its possible mechanisms in PM2.5-induced lung injury. In the present study, mice were intratracheally instilled with PM2.5 dissolved in sterile water to induce lung injury with or without intragastric administration of melatonin. The results showed that melatonin treatment significantly alleviated lung pathological injury and edema, apart from inhibiting inflammatory cell infiltration. Meantime, melatonin also decreased the makers of ferroptosis and lipid peroxidation products in lung tissues challenged with PM2.5. Additionally, melatonin promoted the nuclear translocation and expression of Nrf2 and the protein degradation of Keap1. However, the pulmonary protection and anti-ferroptosis effect of melatonin were counteracted in Nrf2-deficiency mice. In vitro experiments further demonstrated that Nrf2 knockdown could offset anti-ferroptosis effect of melatonin in MLE-12 lung epithelial cells. Taken together, our study disclosed that melatonin could relieve PM2.5-induced lung injury via inhibiting ferroptosis of lung epithelial cells by activating Nrf2. Hence, melatonin may be a promising candidate against lung injury associated with air particulate matter.

The critical roles of histone deacetylase 3 in the pathogenesis of solid organ injury

Histone deacetylase 3 (HDAC3) plays a crucial role in chromatin remodeling, which, in turn, regulates gene transcription. Hence, HDAC3 has been implicated in various diseases, including ischemic injury, fibrosis, neurodegeneration, infections, and inflammatory conditions. In addition, HDAC3 plays vital roles under physiological conditions by regulating circadian rhythms, metabolism, and development. In this review, we summarize the current knowledge of the physiological functions of HDAC3 and its role in organ injury. We also discuss the therapeutic value of HDAC3 in various diseases.

Particulate Matter-Induced Cardiovascular Dysfunction: A Mechanistic Insight

Air pollution and particulate matter (PM) are significant factors for adverse health effects most prominently cardiovascular disease (CVD). PM is produced from various sources, which include both natural and anthropogenic. It is composed of biological components, organic compounds, minerals, and metals, which are responsible for inducing inflammation and adverse health effects. However, the adverse effects are related to PM size distribution. Finer particles are a significant cause of cardiovascular events. This review discusses the direct and indirect mechanisms of PM-induced CVD like myocardial infarction, the elevation of blood pressure, cardiac arrhythmias, atherosclerosis, and thrombosis. The two potential mechanisms are oxidative stress and systemic inflammation. Prenatal exposure has also been linked with cardiovascular outcomes later in life. Moreover, we also mentioned the epidemiological studies that strongly associate PM with CVD.