Ultrafine particles and platelet activation in patients with coronary heart disease--results from a prospective panel study

Nuclear Waste Tank Emission Contributions to Particle Size Distribution

ABSTRACT

Pollutants from anthropogenic activities including industrial processes are ubiquitous to the environment. To understand the impact from industrial aerosol on climate and human health, industrial aerosol needs to be better characterized. In this study, particle number concentrations were used as a proxy for atmospheric pollutants, which include both particles and gases. Particle concentration and size distribution were measured using a scanning mobility particle sizer (SMPS) approximately 4.5 km from primary industrial areas at the Savannah River Site in Aiken, SC. Industrial areas include numerous nuclear waste storage and processing tanks. The SMPS data were divided into two groups depending on the wind direction measured onsite to categorize transport from the industrial area or from elsewhere. Industrial contributions were found to have a higher concentration of particles with sizes less than 200 nm, 859 ± 564 cm-3, in comparison to non-industrial attributed particles, 733 ± 495 cm-3 on average from March-July 2021. For sizes larger than 200 nm, industrial and non-industrial particles have a similar concentration, 89 ± 59 cm-3 and 99 ± 61 cm-3, with non-industrial concentrations being slightly larger. To confirm that industrial particles could travel to the sampling location, air dispersion modeling was completed for specific case studies during the sampling period. The atmospheric dispersion modeling results confirmed that particles released at the industrial areas reached the sampling location when the wind direction was favorable for transport from the industrial areas. The greater concentration of smaller-sized particles in industrial emissions has implications for typical particulate measurements (PM2.5), heath impacts, and climatological influences.

The Association Between Air Pollution Exposure and White Blood Cell Counts: A Nationwide Cross-Sectional Survey in South Korea

Background: The effect of air pollution, a major global health issue, on the immune system, particularly on white blood cell (WBC) counts, remains underexplored. Methods: This study utilized data from 54,756 participants in the Korean National Health and Nutrition Examination Survey to investigate the effects of short- (day of examination and 7-day averages), mid- (30- and 90-day averages), and long-term (one-, three-, and five-year averages) air pollutant exposure on WBC counts. We assessed exposure to particulate matter (PM10, PM2.5), sulfur dioxide (SO2), nitrogen dioxide (NO2), ozone (O3), and carbon monoxide (CO). Results: Linear regression with log-transformed WBC counts, adjusted for confounders, showed that PM10 was positively associated with long-term exposure, PM2.5 was negatively associated with short- and mid-term exposures, SO2 was consistently negatively associated with short- and mid-term exposures, NO2 and CO were positive across most periods, and O3 was negatively associated with short- and mid-term exposures. Logistic regression analysis confirmed these findings, showing that short- and mid-term exposure to PM10, PM2.5, and SO2 was negatively associated with the risk of belonging to the high-WBC group, while long-term exposure to PM10, PM2.5, NO2, and CO showed positive associations with risk. Conclusions: Our findings highlight the time- and pollutant-specific associations between air pollution exposure and WBC counts, underscoring air pollution's potential impact on systemic inflammation.

Influence of gestational hypertension and maternal air pollutant exposure on birth outcomes

The relationship between exposure to air pollutants and fetal growth outcomes has shown inconsistency, and only a limited number of studies have explored the impact of air pollution on gestational hypertension and birth outcomes. This study aimed to evaluate how maternal exposure to air pollutants and blood pressure could influence fetal birth outcomes. A total of 55 women with gestational hypertension and 131 healthy pregnant women were enrolled in this study. Data pertaining to personal characteristics, prenatal examinations, outdoor air pollutant exposure, and fetal birth outcomes were collected. The study revealed that fetal birth weight and abdominal circumference exhibited a significant reduction among women with gestational hypertension compared to healthy pregnant women, even after adjustments for body mass index, gestational age, and exposure to air pollutants had been made. Moreover, maternal exposure to outdoor air pollutants displayed a notable correlation with decreased birth length of fetuses. Consequently, the study concluded that maternal blood pressure and exposure to outdoor air pollutants during pregnancy potentially stand as pivotal factors influencing fetal birth outcomes.

Mechanistic insights into cardiovascular effects of ultrafine particle exposure: A longitudinal panel study

BACKGROUND

Ultrafine particle (UFP) has been linked with higher risks of cardiovascular diseases; however, the biological mechanisms remain to be fully elucidated.

OBJECTIVES

This study aims to investigate the cardiovascular responses to short-term UFP exposure and the biological pathways involved.

METHODS

A longitudinal panel study was conducted among 32 healthy, non-smoking young adults in Shanghai, China, who were engaged in five rounds of follow-ups between December 2020 and November 2021. Individual exposures were calculated based on the indoor and outdoor real-time measurements. Blood pressure, arterial stiffness, targeted biomarkers, and untargeted proteomics and metabolomics were examined during each follow-up. Linear mixed-effect models were applied to analyze the exposure and health data. The differential proteins and metabolites were used for pathway enrichment analyses.

RESULTS

Short-term UFP exposure was associated with significant increases in blood pressure and arterial stiffness. For example, systolic blood pressure increased by 2.10 % (95 % confidence interval: 0.63 %, 3.59 %) corresponding to each interquartile increase in UFP concentrations at lag 0-3 h, while pulse wave velocity increased by 2.26 % (95 % confidence interval: 0.52 %, 4.04 %) at lag 7-12 h. In addition, dozens of molecular biomarkers altered significantly. These effects were generally present within 24 h after UFP exposure, and were robust to the adjustment of co-pollutants. Molecular changes detected in proteomics and metabolomics analyses were mainly involved in systemic inflammation, oxidative stress, endothelial dysfunction, coagulation, and disturbance in lipid transport and metabolism.

DISCUSSION

This study provides novel and compelling evidence on the detrimental subclinical cardiovascular effects in response to short-term UFP exposure. The multi-omics profiling further offers holistic insights into the underlying biological pathways.

Quantifying particle concentration via AI-enhanced optical coherence tomography

Efficient and robust quantification of the number of nanoparticles in solution is not only essential but also insufficient in nanotechnology and biomedical research. This paper proposes to use optical coherence tomography (OCT) to quantify the number of gold nanorods, which exemplify the nanoparticles with high light scattering signals. Additionally, we have developed an AI-enhanced OCT image processing to improve the accuracy and robustness of the quantification result.

Integrating 4-D light-sheet fluorescence microscopy and genetic zebrafish system to investigate ambient pollutants-mediated toxicity

Ambient air pollutants, including PM2.5 (aerodynamic diameter d ~2.5 μm), PM10 (d ~10 μm), and ultrafine particles (UFP: d < 0.1 μm) impart both short- and long-term toxicity to various organs, including cardiopulmonary, central nervous, and gastrointestinal systems. While rodents have been the principal animal model to elucidate air pollution-mediated organ dysfunction, zebrafish (Danio rerio) is genetically tractable for its short husbandry and life cycle to study ambient pollutants. Its electrocardiogram (ECG) resembles that of humans, and the fluorescent reporter-labeled tissues in the zebrafish system allow for screening a host of ambient pollutants that impair cardiovascular development, organ regeneration, and gut-vascular barriers. In parallel, the high spatiotemporal resolution of light-sheet fluorescence microscopy (LSFM) enables investigators to take advantage of the transparent zebrafish embryos and genetically labeled fluorescent reporters for imaging the dynamic cardiac structure and function at a single-cell resolution. In this context, our review highlights the integrated strengths of the genetic zebrafish system and LSFM for high-resolution and high-throughput investigation of ambient pollutants-mediated cardiac and intestinal toxicity.

Modern Concepts of the Role of Fine Particles (PM 2.5) in the Genesis of Atherosclerosis and Myocardial Damage: Clinical and Epidemiological Data, the Main Pathophysiological Mechanisms

Due to the fact that atherosclerotic cardiovascular diseases (CVDs) dominate in the structure of morbidity, disability and mortality of the population, the study of the risk factors for the development of atherosclerotic CVDs, as well as the study of the underlying pathogenetic mechanisms thereof, is the most important area of scientific research in modern medicine. Understanding these aspects will allow improving the set of treatment and preventive measures and activities. One of the important risk factors for the development of atherosclerosis, which has been actively studied recently, is air pollution with fine particulate matter (PM 2.5). According to clinical and epidemiological data, the level of air pollution with PM 2.5 exceeds the normative indicators in most regions of the world and is associated with subclinical markers of atherosclerosis and mortality from atherosclerotic CVDs. The aim of this article is to systematize and discuss in detail the role of PM 2.5 in the development of atherosclerosis and myocardial damage with the consideration of epidemiological and pathogenetic aspects. Materials and Methods: This narrative review is based on the analysis of publications in the Medline, PubMed, and Embase databases. The terms "fine particles" and "PM 2.5" in combination with "pathophysiological mechanisms," "cardiovascular diseases", "atherosclerosis", "cardiac troponins", "myocardial damage" and "myocardial injury" were used to search publications. Conclusion: According to the conducted narrative review, PM 2.5 should be regarded as the significant risk factor for the development of atherosclerotic CVDs. The pro-atherogenic effect of fine particulate matter is based on several fundamental and closely interrelated pathophysiological mechanisms: endothelial dysfunction, impaired lipid metabolism, increased oxidative stress and inflammatory reactions, impaired functioning of the vegetative nervous system and increased activity of the hemostatic system. In addition, PM 2.5 causes subclinical damage to cardiac muscle cells by several mechanisms: apoptosis, oxidative stress, decreased oxygen delivery due to coronary atherosclerosis and ischemic damage of cardiomyocytes. Highly sensitive cardiac troponins are promising markers for detecting subclinical myocardial damage in people living in polluted regions.

Association between solid fuel combustion and diabetes mellitus: a systematic review and meta-analysis

In recent years, many epidemiological studies have investigated the relationship between solid fuel combustion and diabetes mellitus (DM). This meta-analysis was performed to explore the potential association between solid fuel combustion and DM. A comprehensive literature search was conducted to identify all relevant studies published prior to January 14, 2022. The pooled odds ratios (OR) with 95% confidence intervals (CI) were used to estimate the effect of solid fuel combustion on DM. The I square value (I²) was used to assess heterogeneity. Due to the heterogeneity of the studies (I² = 66.70%), a random-effect model was used as the pooling method. A total of 9 articles (10 available datasets) were used for this systematic review and meta-analysis, involving 45,620 study subjects. The results of the meta-analysis showed a statistically positive relationship between household solid fuel combustion and the risk of DM (OR = 1.46, 95% CI = 1.09-1.97). Subgroup analysis based on fuel type revealed a statistically significant association in the mixed solid fuel group (OR = 2.03, 95% CI = 1.59-2.59), but not in the single biomass group (OR = 1.04, 95% CI = 0.73-1.49). This meta-analysis suggests that solid fuel combustion may be associated with an increased risk of DM.

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.

Short-Term Exposure of PM2.5 and Epigenetic Aging: A Quasi-Experimental Study

Epigenetic age (EA) is an emerging DNA methylation-based biomarker of biological aging, but whether EA is causally associated with short-term PM_2.5 exposure remains unknown. We conducted a quasi-experimental study of 26 healthy adults to test whether short-term PM_2.5 exposure accelerates seven EAs with three health examinations performed before, during, and after multiple PM_2.5 pollution waves. Seven EAs were derived from the DNA methylation profiles of the Illumina HumanMethylationEPIC BeadChip from CD4+ T-helper cells. We found that an increase of 10 μg/m³ in the 0-24 h personal PM_2.5 exposure prior to health examinations was associated with a 0.035, 0.035, 0.050, 0.055, 0.052, and 0.037-unit increase in the changes of z-scored DNA methylation age acceleration (AA,Horvath), AA (Hannum), AA (GrimAge), DunedinPoAm, mortality risk score (MS), and epiTOC, respectively (p-values < 0.05). The same increase in the 24-48 h average personal PM_2.5 exposure yielded smaller effects but was still robustly associated with the changes in AA (GrimAge), DunedinPoAm, and MS. Such acute aging effects of PM_2.5 were mediated by the changes in several circulating biomarkers, including EC-SOD and sCD40L, with up to ∼28% mediated proportions. Our findings demonstrated that short-term PM_2.5 exposure could accelerate aging reflected by DNA methylation profiles via blood coagulation, oxidative stress, and systematic inflammation.

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

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

Clustering of Environmental Parameters and the Risk of Acute Myocardial Infarction

The association between days with similar environmental parameters and cardiovascular events is unknown. We investigate the association between clusters of environmental parameters and acute myocardial infarction (AMI) risk in Singapore. Using k-means clustering and conditional Poisson models, we grouped calendar days from 2010 to 2015 based on rainfall, temperature, wind speed and the Pollutant Standards Index (PSI) and compared the incidence rate ratios (IRR) of AMI across the clusters using a time-stratified case-crossover design. Three distinct clusters were formed with Cluster 1 having high wind speed, Cluster 2 high rainfall, and Cluster 3 high temperature and PSI. Compared to Cluster 1, Cluster 3 had a higher AMI incidence with IRR 1.04 (95% confidence interval 1.01–1.07), but no significant difference was found between Cluster 1 and Cluster 2. Subgroup analyses showed that increased AMI incidence was significant only among those with age ≥65, male, non-smokers, non-ST elevation AMI (NSTEMI), history of hyperlipidemia and no history of ischemic heart disease, diabetes or hypertension. In conclusion, we found that AMI incidence, especially NSTEMI, is likely to be higher on days with high temperature and PSI. These findings have public health implications for AMI prevention and emergency health services delivery during the seasonal Southeast Asian transboundary haze.

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

Short-term exposure to fine particulate matter (PM_2.5) increases thrombotic risk particularly in obese individuals, but the underlying mechanisms remain unclear. This study aims to compare the effects of PM_2.5 on inflammation and platelet activation in obese versus normal-weight adults, and investigate potential causal pathways. We conducted a panel study measuring blood markers in 44 obese and 53 normal-weight adults on 3 separate occasions in 2017-2018. Associations between PM_2.5/black carbon (BC) and biomarkers were estimated using mixed-effect models. An interaction analysis compared PM_2.5/BC-related effects between subgroups. Biomarker combinations and mediation analysis were performed to elucidate the biological pathways. There was a significant "low-high-low" trend of PM_2.5 levels across the 3 study periods. Increases in pro-inflammatory cytokines and changes of platelet activation and aggregation markers were associated with PM_2.5/BC in obese subgroup only. Among obese subjects, the combination of pro-inflammatory cytokines and that of platelet markers increased 26.8% (95% CI: 16.0%, 37.9%) and 14.7% (95% CI: 1.9%, 27.0%) per IQR increase in PM_2.5 over 5-day and 7-day averages. Inflammation mediated 24.5% of the pathways through which PM_2.5 promoted platelet activation. This study suggested obese people are susceptible to pro-thrombotic impacts of PM_2.5 exposures. PM_2.5 may aggravate thrombosis through obesity-related inflammation.

Clinical outcomes associated with long-term exposure to airborne particulate pollution in kidney transplant recipients

BACKGROUND

Researchers have yet to investigate the specific association between 10-μm particulate matter (PM10) levels and the risk of graft failure, kidney disease, or the functional decline of transplanted kidneys, in kidney transplant recipients (KTRs). Furthermore, we know very little about the association between PM10 levels and the development of allograft rejection in transplanted kidneys. Identification of air pollution as a potential contributor to kidney disease could help reduce future disease burden, stimulate policy discussions on the importance of reducing air pollution with respect to health and disease, and increase public awareness of the hazards of air pollution. We aimed to evaluate the relationship of PM10 with the risk of graft failure, mortality, and decline of graft function in KTRs.

METHODS

Air pollutant data were obtained from the Korean National Institute of Environmental Research. We then investigated potential associations between these data and the clinical outcomes of 1532 KTRs who underwent kidney transplantation in a tertiary hospital between 2001 and 2015. Survival models were used to evaluate the association between PM10 concentrations and the risk of death-censored graft failure (DCGF), all-cause mortality, and biopsy-proven rejection (BPR), over a median follow-up period of 6.31 years.

RESULTS

The annual mean PM10 exposure after kidney transplantation was 27.1 ± 8.0 μg/m3. Based on 1-year baseline exposure, 1 μg/m3 increase in PM10 concentration was associated with an increased risk of DCGF (hazard ratio (HR): 1.049; 95% confidence interval (CI): 1.014-1.084) and BPR (HR: 1.053; 95% CI: 1.042-1.063). Fully adjusted models showed that all-cause mortality was significantly associated with 1-year average PM10 concentrations (HR, 1.09; 95% CI, 1.043 to 1.140).

CONCLUSIONS

Long-term PM10 exposure is significantly associated with BPR, DCGF, and all-cause mortality in KTRs.

[Effects of ultrafine particulates on cardiac function in rat isolated heart]

OBJECTIVE

To evaluate whether ultrafine particulates (UFPs) have direct deleterious effects on cardiac function through activating MAPK signaling.

METHODS

Langendorff-perfused Sprague-Dawley rat hearts were randomly divided into 2 groups (n=10/each group). In control group, the rat hearts were perfused with Tyrode's buffer for 40 min; in UFPs-treated group, the hearts were perfused with UFPs at a concentration of 12.5 mg/L. Cardiac function was determined by measuring left ventricular developed pressure (LVDP), left ventricular peak rate of contraction and relaxation (±dp/dt_max) and coronary flow (CF). The levels of malondialdehyde (MDA), superoxide dismutase (SOD), total anti-oxidant capacity (TAOC) were detected in order to evaluate cardiac oxidative stress via the thiobarbituric acid assay, water soluble tetrazolium salt assay and colorimetry, respectively. The expressions of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium were observed using immunohistochemical staining and Western blots.

RESULTS

No significant changes in cardiac function were detected before and after the perfusion in control group while UFPs perfused hearts showed a decline in cardiac function in a time-dependent manner (all P < 0.05). In UFPs-treated group, LVDP, +dp/dt_max, -dp/dt_max and CF were statistically reduced from (82.6±2.1) mmHg, (1 624±113) mmHg/s, (1 565±116) mmHg/s, (12.0±0.2) mL/min to (56.8±4.4) mmHg, (1 066±177) mmHg/s, (1 082±134) mmHg/s, (8.7±0.3) mL/min (all P < 0.05), respectively. Furthermore, The comparison between the two groups observed that UFPs perfusion caused a significant decrease in cardiac function at 30 and 40 min compared with the control group (all P < 0.05). At the end of the perfusion, the level of MDA was increased from (0.98±0.14) nmol/L to (1.95±0.18) nmol/L, while SOD and TAOC were reduced from (12.50±1.87) U/mL and (6.83±1.16) U/mL to (6.50 ±1.04) U/mL and (3.67±0.82) U/mL (all P < 0.001) in UFPs group, respectively. In coincidence with these changes, immunohistochemistry and Western blots results showed that the levels of p-p38 MAPK, p-ERKs and p-JNKs in the myocardium significantly increased in UFPs group as compared with control group (all P < 0.05).

CONCLUSION

The results of this study demonstrated that the short-term exposure of UFPs to the isolated rat hearts has direct and acute toxic effects on cardiac function, probably related to attenuation of anti-oxidative capacity and activation of MAPK signaling pathways.

The Protective Effects of Shengmai Formula Against Myocardial Injury Induced by Ultrafine Particulate Matter Exposure and Myocardial Ischemia are Mediated by the PI3K/AKT/p38 MAPK/Nrf2 Pathway

Background and Purpose: Ultrafine particulate matter (UFPM) induces oxidative stress (OS) and is considered to be a risk factor of myocardial ischemia (MI). Shengmai formula (SMF) is a traditional Chinese medicine with antioxidant properties and has been used to treat cardiovascular diseases for a long time. The aim of this study was to explore the protective role of SMF and the mechanism by which it prevents myocardial injury in UFPM-exposed rats with MI. Methods: An MI rat model was established. Animals were randomly divided into five groups: sham, UFPM + MI, SMF (1.08 mg/kg⋅d) + UFPM + MI, SMF (2.16 mg/kg⋅d) + UFPM + MI, and SMF (4.32 mg/kg⋅d) + UFPM + MI. SMF or saline was administrated 7 days before UFPM instillation (100 μg/kg), followed by 24 h of ischemia. Physiological and biochemical parameters were measured, and histopathological examinations were conducted to evaluate myocardial damage. We also explored the potential mechanism of the protective role of SMF using a system pharmacology approach and an in vitro myoblast cell model with small molecule inhibitors. Results: UFPM produced myocardial injuries on myocardial infarct size; serum levels of LDH, CK-MB, and cardiac troponin; and OS responses in the rats with MI. Pretreatment with SMF significantly attenuated these damages via reversing the biomarkers. SMF also improved histopathology induced by UFPM and significantly altered the PI3K/AKT/MAPK and OS signaling pathways. The expression patterns of Cat, Gstk1, and Cyba in the UFPM model group were reversed in the SMF-treated group. In in vitro studies, SMF attenuated UFPM-induced reactive oxygen species production, mitochondrial damage, and OS responses. The PI3K/AKT/p38 MAPK/Nrf2 pathway was significantly changed in the SMF group compared with that in the UFPM group, whereas opposite results were obtained for pathway inhibition. Conclusion: These findings indicate that SMF prevents OS responses and exerts beneficial effects against myocardial injury induced by UFPM + MI in rats. Furthermore, the PI3K/AKT/p38 MAPK/Nrf2 signaling pathway might be involved in the protective effects of SMF.

The Association of White Blood Cells and Air Pollutants-A Population-Based Study

The links of air pollutants to health hazards have been revealed in literature and inflammation responses might play key roles in the processes of diseases. WBC count is one of the indexes of inflammation, however the l iterature reveals inconsistent opinions on the relationship between WBC counts and exposure to air pollutants. The goal of this population-based observational study was to examine the associations between multiple air pollutants and WBC counts. This study recruited community subjects from Kaohsiung city. WBC count, demographic and health hazard habit data were collected. Meanwhile, air pollutants data (SO₂, NO₂, CO, PM₁₀, and O₃) were also obtained. Both datasets were merged for statistical analysis. Single- and multiple-pollutants models were adopted for the analysis. A total of 10,140 adults (43.2% males; age range, 33~86 years old) were recruited. Effects of short-term ambient concentrations (within one week) of CO could increase counts of WBC, neutrophils, monocytes, and lymphocytes. However, SO₂ could decrease counts of WBC, neutrophils, and monocytes. Gender, BMI, and smoking could also contribute to WBC count increases, though their effects are minor when compared to CO. Air pollutants, particularly SO₂, NO₂ and CO, may thus be related to alterations of WBC counts, and this would imply air pollution has an impact on human systematic inflammation.

Seasonal association between ambient fine particulate matter and venous thromboembolism in Beijing, China: a time-series study

Little is known about the influence of ambient fine particulate matter (PM2.5) on the incidence of venous thromboembolism in areas with heavy air pollution. We examined seasonal associations between airborne concentrations of fine particulate matter and outpatient visits for venous thromboembolism in Beijing using a city-wide time-series design that covered a period of 30 months (January 1, 2010 to June 30, 2012). Generalized additive models were used to investigate the associations with adjustment of temperature for various time lags (lag 0 for the warm season and lag 0-10 for the cold season). Overall, 92,435 outpatient visits were recorded by the Beijing Medical Claim Data for Employees database during the study period. We found a significant association between PM2.5 levels and outpatient visits for venous thromboembolism. A 10-μg/m3 increase in PM2.5 concentrations on lag days 0-2 corresponded to a 0.64% (95% confidence interval: 0.55-0.73%; P < 0.001) increase in outpatient visits for venous thromboembolism during the cold season, and a 10-μg/m3 increase in PM2.5 concentrations on lag days 0-3 corresponded to a 0.82% (95% confidence interval: 0.67-0.96%; P < 0.001) increase in outpatient visits for venous thromboembolism during the warm season. Our findings suggest that PM2.5 exposure is associated with outpatient visits for venous thromboembolism in Beijing, and a more pronounced association was observed during the warm season. We propose that various temperature-adjustment strategies should be used when investigating seasonal associations.

All-polymer hybrid electret fibers for high-efficiency and low-resistance filter media

A one-step and controllable strategy to prepare all-polymer hybrid electret fibers is reported based on the coupling of polystyrene and polyvinylidene fluoride in electric response. The complementary dielectric properties between PS and PVDF generate dual-system electret charges within PS/PVDF fibers, thereby improving the electret effect. The bi-component all-polymer electret fibers show enhanced electret property and structural continuity, contributing to a N95 protective respirator with high filtration efficiency (99.752%), low air resistance (72 Pa) and long service life. The fabrication of all-polymer electret fibers solves the challenge of nanoparticle toxicity for existing polymer/nanoparticle electret fibers.

Environmental determinants of cardiovascular disease: lessons learned from air pollution

Air pollution is well recognized as a major risk factor for chronic non-communicable diseases and has been estimated to contribute more to global morbidity and mortality than all other known environmental risk factors combined. Although air pollution contains a heterogeneous mixture of gases, the most robust evidence for detrimental effects on health is for fine particulate matter (particles ≤2.5 µm in diameter (PM2.5)) and ozone gas and, therefore, these species have been the main focus of environmental health research and regulatory standards. The evidence to date supports a strong link between the risk of cardiovascular events and all-cause mortality with PM2.5 across a range of exposure levels, including to levels below current regulatory standards, with no 'safe' lower exposure levels at the population level. In this comprehensive Review, the empirical evidence supporting the effects of air pollution on cardiovascular health are examined, potential mechanisms that lead to increased cardiovascular risk are described, and measures to reduce this risk and identify key gaps in our knowledge that could help address the increasing cardiovascular morbidity and mortality associated with air pollution are discussed.

Improving the separation efficient of particles smaller than 2.5 micrometer by combining ultrasonic agglomeration and swirling flow techniques

The method for increasing the separation efficiency of particles smaller than 2.5 micrometers by combined ultrasonic agglomeration and swirling flow technique is proposed in the article. The swirling flow creates areas with an increased concentration of particles on the outer radius of the vortex. The ultrasonic exposure on these areas leads to more efficient agglomeration and the formation of agglomerates of many times larger than the original particles. The resulting agglomerates are easily separated from the gas flow. The design of the agglomerator was developed. The vortex velocity is determined, at which ultrasonic exposure on the swirling flow increases the average particle size d32 = 2.5 micrometer to 4.5 times. The ultrasonic exposure on a rectilinear flow can increase the particle size no more than 1.6 times for comparison. The proposed method is compared with inertial gas clearing in a cyclone. It was found that the proposed combined method allows increasing the cleaning efficiency from 46% to 85% at ultrasonic exposure on the swirling flow in the agglomerator and cyclone.

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

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

Impact of Sea Breeze Dynamics on Atmospheric Pollutants and Their Toxicity in Industrial and Urban Coastal Environments

Sea breeze (SB) phenomena may strongly influence air quality and lead to important effects on human health. In order to study the impact of SB dynamics on the properties and toxicity of aerosols, an atmospheric mobile unit was deployed during a field campaign performed in an urbanized and industrialized coastal area in Northern France. This unit combines aerosol samplers, two scanning lidars (Doppler and elastic) and an air-liquid interface (ALI, Vitrocell®) in vitro cell exposure device. Our study highlights that after the passage of an SB front, the top of the atmospheric boundary layer collapses as the thermal internal boundary layer (TIBL) develops, which leads to high aerosol extinction coefficient values (>0.4 km−1) and an increase of PM2.5 and NOx concentrations in the SB current. The number-size distribution of particles indicates a high proportion of fine particles (with diameter below 500 nm), while the volume-size distribution shows a major mode of coarse particles centered on 2–3 µm. Individual particle analyses performed by cryo-transmission scanning electron microscopy (cryo-TSEM)-EDX highlights that submicronic particles contained a high fraction of secondary compounds, which may result from nucleation and/or condensation of condensable species (vapors or gaseous species after photo-oxidation). Secondary aerosol (SA) formation can be enhanced in some areas, by the interaction between the SB flow and the upper continental air mass, particularly due to the effect of both turbulence and temperature/humidity gradients between these two contrasting air masses. Potential areas of SA formation are located near the ground, during the SB front passage and in the vicinity of the SB current top. During the sea breeze event, an increase in the oxidative stress and inflammation processes in exposed lung cells, compared to the unexposed cells, can also be seen. In some instances, short singularity periods are observed during SB, corresponding to a double flow structure. It consists of two adjacent SB currents that induce an important increase of the TIBL top, improving the pollutants dispersion. This is associated with a substantial decrease of aerosol mass concentrations.

The effect of glycyrrhizin acid on Bax and Bcl2 expression in hepatotoxicity induced by Titanium dioxide nanoparticles in rats

AIM

This research studied the effects of glycyrrhizic acid (GA) on apoptosis induced with by titanium dioxide (NTiO2) in the liver of rats.

BACKGROUND

It is widely accepted that the contamination resulting from nanoparticles (NPs) is an emerging dangerous issue. Metal oxide nanoparticles have high environmental stability and cause toxicity in the food chain. Thus, the present study investigated the anti-apoptotic effects of glycyrrhizic acid (GA) on the hepatotoxicity generated by titanium dioxide (NTiO2) NPs in the liver tissue.

METHODS

Thirty-two male Wistar rats were randomly divided into four groups. NTiO2-treated rats were given 300 mg / kg of NTiO2 solution via gavage for 14 days; GA-treated were administered 100 mg/kg GA for 14 days; protection group was pre-treated with GA before NTiO2 administration for 7 days. Then, apoptotic index was evaluated through immunolocalization of Bax and Bcl-2 and TUNEL assay.

RESULTS

we found that HSCORE of Bax expression and apoptotic index experienced a significant increase with NTiO2 (P <0.001), while Bcl-2 expression significantly diminished in NTiO2-treated rats (P <0.001). The results revealed that the increased Bax expression and apoptotic index were reversed by GA and enhanced the activities of Bcl2.

CONCLUSION

The results revealed that GA effectively attenuated apoptosis against NTiO2 in rats.

Developing A Low Cost Particulate Matter Measurement System

A low cost particulate matter measurement system has been designed to quantify the concentration in the air. The device has been built up by using a PM2.5 sensor. The sensor signal is processed and transfer to an Arduino UNO microcontroller. A long-range wireless communication is attached in the system for a distance measurement. The system has been validated using a 3522 Kanomax dust monitor model. The system was tested in the distance to characterize the performance. The system works properly to measure PM2.5 concentration. The PM2.5 concentration is presented in the average value of the 30 seconds sampling measurement. The system is controlled by using humidity and temperature sensor to avoid any damage caused by an environment condition. The maximum humidity and temperature for the system is restricted to 70% and 50°C respectively. The measurement system is accomplished to a NRF2401 radio module to allow to collect data remotely. In conclusion, the proposed system works well to measure PM2.5 in the environment. The system has an ability to measure particulate matter with maximum concentration of 750.0 μg/m3 with the resolution of 0.3 μg/m3.

Dynamic behavior of indoor ultrafine particles (2.3-64 nm) due to burning candles in a residence

A major source of human exposure to ultrafine particles is candle use. Candles produce ultrafine particles in the size range under 10 nm, with perhaps half of the particles less than 5 nm. For these small particles at typically high concentrations, coagulation and deposition are two dominant mechanisms in aerosol size dynamics. We present an updated coagulation model capable of characterizing the relative contributions of coagulation, deposition, and air exchange rates. Size-resolved coagulation and decay rates are estimated for three types of candles. Number, area, and mass distributions are provided for 93 particle sizes from 2.33 to 64 nm. Total particle production was in the range of 10¹³  min^-1 . Peak number, area, and mass concentrations occurred at particle sizes of <3, 20, and 40 nm, respectively. Both the number and area concentrations greatly exceeded background concentrations in the residence studied. Contributions of coagulation, deposition, and air exchange rates to particle losses were 65%, 34%, and 0.3% at high concentrations (10⁶  cm^-3 ), while they are 17%, 81%, and 1.7% at lower concentrations (3 × 10⁴  cm^-3 ), respectively. The increased particle production for the very smallest particles (2.33-2.50 nm) suggests that even smaller particles may be important to study.

Novel evidence for a greater burden of ambient air pollution on cardiovascular disease

Ambient and household air pollution is a major health problem worldwide, contributing annually to approximately seven million of all-cause avoidable deaths, shorter life expectancy, and significant direct and indirect costs for the community. Air pollution is a complex mixture of gaseous and particulate materials that vary depending on their source and physicochemical features. Each material has detrimental effects on human health, but a number of experimental and clinical studies have shown a strong impact for fine particulate matter (PM_2.5). In particular, there is more and more evidence that PM_2.5 exerts adverse effects particularly on the cardiovascular system, contributing substantially (mainly through mechanisms of atherosclerosis, thrombosis and inflammation) to coronary artery and cerebrovascular disease, but also to heart failure, hypertension, diabetes and cardiac arrhythmias. In this review, we summarize knowledge on the mechanisms and magnitude of the cardiovascular adverse effects of short-and long-term exposure to ambient air pollution, particularly for the PM_2.5 size fraction. We also emphasize that very recent data indicate that the global mortality and morbidity burden of cardiovascular disease associated with this air pollutant is dramatically greater than what has been thought up to now.

Short-term exposure to ambient air pollution and circulating biomarkers of endothelial cell activation: The Framingham Heart Study

BACKGROUND

Short-term exposure to air pollution has been associated with cardiovascular events, potentially by promoting endothelial cell activation and inflammation. A few large-scale studies have examined the associations and have had mixed results.

METHODS

We included 3820 non-current smoking participants (mean age 56 years, 54% women) from the Framingham Offspring cohort examinations 7 (1998-2001) and 8 (2005-2008), and Third Generation cohort examination 1 (2002-2005), who lived within 50 km of a central monitoring station. We calculated the 1- to 7-day moving averages of fine particulate matter (PM_2.5), black carbon (BC), sulfate (SO₄^2-), nitrogen oxides (NO_x), and ozone before examination visits. We used linear mixed effect models for P-selectin, monocyte chemoattractant protein 1 (MCP-1), intercellular adhesion molecule 1, lipoprotein-associated phospholipase A2 activity and mass, and osteoprotegerin that were measured up to twice, and linear regression models for CD40 ligand and interleukin-18 that were measured once, adjusting for demographics, life style and clinical factors, socioeconomic position, time, and meteorology.

RESULTS

We found negative associations of PM_2.5 and BC with P-selectin, of ozone with MCP-1, and of SO₄^2- and NO_x with osteoprotegerin. At the 5-day moving average, a 5 µg/m³ higher PM_2.5 was associated with 1.6% (95% CI: - 2.8, - 0.3) lower levels of P-selectin; a 10 ppb higher ozone was associated with 1.7% (95% CI: - 3.2, - 0.1) lower levels of MCP-1; and a 20 ppb higher NO_x was associated with 2.0% (95% CI: - 3.6, - 0.4) lower levels of osteoprotegerin.

CONCLUSIONS

We did not find evidence of positive associations between short-term air pollution exposure and endothelial cell activation. On the contrary, short-term exposure to higher levels of ambient pollutants were associated with lower levels of P-selectin, MCP-1, and osteoprotegerin in the Framingham Heart Study.

Pure ultra-fine carbon particles do not exert pro-coagulation and inflammatory effects on microvascular endothelial cells

Pro-thrombotic and inflammatory changes play an important role in cardiovascular morbidity and mortality, resulting from short-term exposure to fine particulate air-pollution. Part of those effects has been attributed to the ultra-fine particles (UFPs) that pass through the lung and directly contact blood-exposed and circulating cells. Despite UFP-induced platelet activation, it is unclear whether the penetrated particles exert any direct effect on endothelial cells. While exposure levels are boosting as a result of world-wide increases in economic development and desertification, which create more air-polluted regions, as well as increase in demands for synthetic UFPs in medicine and various industries, further studies on the health effects of these particles are required. In this study, human pulmonary and cardiac microvascular endothelial cells (MECs) have been exposed to 0.1, 1, 10, and 100 μg/ml suspensions of either a natural (carbon black) or a synthetic (multi-walled carbon nano-tubes) type of UFPs, in vitro. As a result, no changes in the levels of coagulation factor VIII, Von Willebrand factor, Interleukin 8, and P-selectin measured in the cells' supernatant were observed prior to and 6, 12, and 24 h after exposure. In parallel, the spatio-temporal effect of UFPs on cardiac MECs was evaluated by Transmission Electron Microscopy. Despite phagocytic uptake of pure UFPs observed on cellular sections of the treated cells, Weibel-Palade bodies remained intact in shape and similar in number when compared with the untreated cells. Our work shows that carbon itself is a non-toxic carrier for endothelial cells.

Short-term Effect of Ambient Air Pollution on Emergency Department Visits for Diabetic Coma in Seoul, Korea

Objectives

A positive association between air pollution and both the incidence and prevalence of diabetes mellitus (DM) has been reported in some epidemiologic and animal studies, but little research has evaluated the relationship between air pollution and diabetic coma. Diabetic coma is an acute complication of DM caused by diabetic ketoacidosis or hyperosmolar hyperglycemic state, which is characterized by extreme hyperglycemia accompanied by coma. We conducted a time-series study with a generalized additive model using a distributed-lag non-linear model to assess the association between ambient air pollution (particulate matter less than 10 μm in aerodynamic diameter, nitrogen dioxide [NO₂], sulfur dioxide, carbon monoxide, and ozone) and emergency department (ED) visits for DM with coma in Seoul, Korea from 2005 to 2009.

Methods

The ED data and medical records from the 3 years previous to each diabetic coma event were obtained from the Health Insurance Review and Assessment Service to examine the relationship with air pollutants.

Results

Overall, the adjusted relative risks (RRs) for an interquartile range (IQR) increment of NO₂ was statistically significant at lag 1 (RR, 1.125; 95% confidence interval [CI], 1.039 to 1.219) in a single-lag model and both lag 0-1 (RR, 1.120; 95% CI, 1.028 to 1.219) and lag 0-3 (RR, 1.092; 95% CI, 1.005 to 1.186) in a cumulative-lag model. In a subgroup analysis, significant positive RRs were found for females for per-IQR increments of NO₂ at cumulative lag 0-3 (RR, 1.149; 95% CI, 1.022 to 1.291).

Conclusions

The results of our study suggest that ambient air pollution, specifically NO₂, is associated with ED visits for diabetic coma.

Recent Advances in Shiga Toxin-Producing Escherichia coli Research in Latin America

Pathogenic Escherichia coli are known to be a common cause of diarrheal disease and a frequently occurring bacterial infection in children and adults in Latin America. Despite the effort to combat diarrheal infections, the south of the American continent remains a hot spot for infections and sequelae associated with the acquisition of one category of pathogenic E. coli, the Shiga toxin-producing E. coli (STEC). This review will focus on an overview of the prevalence of different STEC serotypes in human, animals and food products, focusing on recent reports from Latin America outlining the recent research progress achieved in this region to combat disease and endemicity in affected countries and to improve understanding on emerging serotypes and their virulence factors. Furthermore, this review will highlight the progress done in vaccine development and treatment and will also discuss the effort of the Latin American investigators to respond to the thread of STEC infections by establishing a multidisciplinary network of experts that are addressing STEC-associated animal, human and environmental health issues, while trying to reduce human disease. Regardless of the significant scientific contributions to understand and combat STEC infections worldwide, many significant challenges still exist and this review has focus in the Latin American efforts as an example of what can be accomplished when multiple groups have a common goal.

Occupational exposure to ultrafine particles in police officers: no evidence for adverse respiratory effects

Background

Inhalation exposure to fine and ultrafine particles (UFPs) has been associated with respiratory diseases. However, little is known on the quality, threshold levels and concentration of these particles causing adverse health effects.

Methods

The impact of occupational exposure to submicrometer and UFPs was assessed in 30 healthy police shooting instructors by clinical investigation, self-assessment questionnaire, sputum and spirometry and compared to a control group. General laboratory chemistry parameters, circulating cytokines (interleukin [IL]-2, IL-4, IL-5, IL-6, IL-8, interferon-gamma [IFN-γ]), and granulocyte macrophage colony-stimulating factor (GM-CSF) in serum were measured. UFP exposure was recorded by Scanning Mobility Particle Sizer.

Results

Concentrations of submicrometer sized airborne particles (< 700 nm) measured between 3.34 × 10⁵/cm³ and 7.58 × 10⁵/cm³ at shooting sites, with highest concentrations found in the UFP range (< 100 nm). The size of the monodispersed particles ranged from 54.74 ± 16.25 nm to 98.19 ± 22.83 nm. Short term exposure (4 h) to high levels of UFPs caused an increase of IFN-γ in exposed subjects (p = 0.022). 24 h after exposure a significant decrease of IgG, albumin fibrinogen and factor VII was found. Neither directly after 4 h of high levels UFPs exposure nor 24 h after exposure subjective complaints or objective measurements indicating adverse respiratory effects in exposed subjects were found.

Conclusions

No consistent indications for adverse respiratory or inflammatory effects directly following exposure and 24 h after exposure to high levels of UFPs in our study group were detected. However we showed the assessment of short-term exposure effects at a genuine occupational setting, which might is relevant when a risk assessment of high level occupational exposures to UFPs is considered.

Soluble CD40 Ligand and Oxidative Response Are Reciprocally Stimulated during Shiga Toxin-Associated Hemolytic Uremic Syndrome

Shiga toxin (Stx), produced by Escherichia coli, is the main pathogenic factor of diarrhea-associated hemolytic uremic syndrome (HUS), which is characterized by the obstruction of renal microvasculature by platelet-fibrin thrombi. It is well known that the oxidative imbalance generated by Stx induces platelet activation, contributing to thrombus formation. Moreover, activated platelets release soluble CD40 ligand (sCD40L), which in turn contributes to oxidative imbalance, triggering the release of reactive oxidative species (ROS) on various cellular types. The aim of this work was to determine if the interaction between the oxidative response and platelet-derived sCD40L, as consequence of Stx-induced endothelium damage, participates in the pathogenic mechanism during HUS. Activated human glomerular endothelial cells (HGEC) by Stx2 induced platelets to adhere to them. Although platelet adhesion did not contribute to endothelial damage, high levels of sCD40L were released to the medium. The release of sCD40L by activated platelets was inhibited by antioxidant treatment. Furthermore, we found increased levels of sCD40L in plasma from HUS patients, which were also able to trigger the respiratory burst in monocytes in a sCD40L-dependent manner. Thus, we concluded that platelet-derived sCD40L and the oxidative response are reciprocally stimulated during Stx2-associated HUS. This process may contribute to the evolution of glomerular occlusion and the microangiopathic lesions.

Air Pollution and Other Environmental Modulators of Cardiac Function

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

Epidemiology in Germany-general development and personal experience

Did you ever hear about epidemiology in Germany? Starting from an epidemiological desert the discipline has grown remarkably, especially during the last 10-15 years: research institutes have been established, research funding has improved, multiple curriculae in Epidemiology and Public Health are offered. This increase has been quite steep, and now the epidemiological infrastructure is much better. Several medium-sized and even big population cohorts are ongoing, and the number and quality of publications from German epidemiologists has reached a respectable level. My own career in epidemiology started in the field of environmental health. After German reunification I concentrated for many years on environmental problems in East Germany and observed the health benefits after improvement of the situation. Later, I concentrated on population-based cohorts in newborns (GINI/LISA) and adults (KORA, German National Cohort), and on biobanking. This Essay describes the development in Germany after worldwar 2, illustrated by examples of research results and build-up of epidemiological infractructures worth mentioning.

Air particulate matter induced oxidative stress and inflammation in cardiovascular disease and atherosclerosis: The role of Nrf2 and AhR-mediated pathways

Air particulate matter (PM) is an important component of air pollution, which has been reported to play important role in the adverse health effects of the latter. Extensive experimental data and epidemiological studies have shown that the increased cardiovascular morbidity and mortality and atherosclerosis caused by air pollution are mainly due to the PM component. Implicated in these adverse health effects of PM, is their ability to induce oxidative stress and pro-inflammatory events in the vascular system. The association between the cardiovascular ischemic events and atherosclerosis induced by PM has been linked to the ultrafine and fine components. These particles have a high content of redox cyclic chemicals. This, together with their ability to combine with proatherogenic molecules enhanced tissue oxidative stress. Studies have shown that the oxidative stress induced by PM could up-regulates the expression of phase I and phase II metabolize enzymes. This up-regulation occurs by the activation of transcription factors (such as nuclear factor (erythroid-derived 2) -like 2-related factor (Nrf2) and aryl hydrocarbon receptor (AhR)). This review will focus on data supporting the role of oxidative stress and inflammation in PM-induced cardiovascular diseases and atherosclerosis and the importance of Nrf2-and AhR- dependent regulatory pathways in the PM-induced cardiovascular events and atherosclerosis.

Association of short-term exposure to fine particulate matter and nitrogen dioxide with acute cardiovascular effects

This study evaluated whether exposure to fine particulate matter (PM2.5) and nitrogen dioxide (NO2) is associated with cardiovascular effects by examining a panel of 89 healthy subjects in Taipei, Taiwan. The subjects received two health examinations approximately 8months apart in 2013. Brachial-ankle pulse wave velocity (baPWV), a physiological indicator of arterial stiffness, and high-sensitivity C-reactive protein (hsCRP), a biomarker of vascular inflammations, were measured during each examination. Two exposure assessment methods were used for estimating the subjects' exposure to PM2.5 and NO2. The first method involved constructing daily land use regression (LUR) models according to measurements collected at ambient air quality monitoring stations. The second method required combining the LUR estimates with indoor monitoring data at the workplace of the subjects. Linear mixed models were used to examine the association between the exposure estimates and health outcomes. The results showed that a 10-μg/m(3) increase in PM2.5 concentration at a 1-day lag was associated with 2.1% (95% confidence interval: 0.7%-3.6%) and 2.4% (0.8%-4.0%) increases in baPWV based on the two exposure assessment methods, whereas no significant association was observed for NO2. The significant effects of PM2.5 remained in the two-pollutant models. By contrast, NO2, but not PM2.5, was significantly associated with increased hsCRP levels (16.0%-37.3% in single-pollutant models and 26.4%-44.6% in two-pollutant models, per 10-ppb increase in NO2). In conclusion, arterial stiffness might be more sensitive to short-term PM2.5 exposure than is inflammation.

Effect of Fine Particulate Matter (PM2.5) on Rat Placenta Pathology and Perinatal Outcomes

Background

Fine particulate matter with aerodynamic diameters smaller than 2.5 μm (PM_2.5) has been reported to cause adverse effects on human health. Evidence has shown the association between PM_2.5 exposure and adverse perinatal outcomes, and the most common method is epidemiological investigation. We wished to investigate the impact of PM_2.5 on placenta and prenatal outcomes and its related mechanisms in a rat model.

Material/Methods

Pregnant rats were exposed to a low PM_2.5 dose (15 mg/kg) with intratracheal instillation at pregnant day 10 and day 18, while the controls received an equivalent volume normal saline. All rats received cesarean section 24 h after the last intratracheal instillation and were sacrificed with anesthesia. Blood routine tests (BRT) and interleukin-6 (IL-6) were detected for analyzing inflammation and blood coagulation. Placenta tissue sections underwent pathologic examination, and the levels of homogenate glutathione peroxidase (GSH-Px) and methane dicarboxylic aldehyde (MDA) were determined for oxidative stress estimation.

Results

Increased absorbed blastocysts, and lower maternal weight gain and fetal weight were found in the PM_2.5 exposure group compared to controls (p<0.05). Exposure to PM_2.5 caused a significant increase of blood mononuclear cells (PBMC), platelets, and IL-6 levels (P<0.01). There were no differences in GSH-Px and MDA of placenta homogenate between the 2 groups (P>0.05). Placenta pathological examination demonstrated thrombus and chorioamnionitis in the PM_2.5 exposure group.

Conclusions

PM_2.5 exposure can result in placental pathological changes and adverse perinatal outcomes. The placental inflammation and hypercoagulability with vascular thrombosis may play important roles in placental impairment, but oxidative stress appears to be less important.

Aggregation and protein corona formation on gold nanoparticles affect viability and liver functions of primary rat hepatocytes

AIM

We examined the impact of aggregation and protein corona formation of gold nanoparticles (AuNPs) on the cytotoxicity, uptake and metabolism, specifically urea and albumin synthesis, of primary rat hepatocytes.

MATERIALS & METHODS

The AuNPs were synthesized via citrate reduction and the human serum protein corona was preformed on the AuNPs. Primary hepatocytes were isolated from male Wistar rats via two-step in situ collagenase perfusion method, and were dosed with both citrate-capped (AuNP-Cit) and protein corona coated AuNPs (AuNP-Cor).

RESULTS

The AuNP-Cor showed higher cell uptake and reduced cell viability compared with aggregated AuNP-Cit. Urea and albumin secretions showed AuNP dose dependency. Both AuNP-Cit and AuNP-Cor exerted only an acute effect on the albumin synthesis of hepatocytes with no chronic impact.

A structured review of panel studies used to investigate associations between ambient air pollution and heart rate variability

INTRODUCTION

Dysfunction of the autonomic nervous system is one of the postulated pathways linking short-term exposure to air pollution to adverse cardiovascular outcomes. A hypothesis is that exposure to air pollution decreases heart rate variability, a recognized independent predictor of poorer cardiovascular prognosis.

METHODS

We conducted a structured review of panel studies published between 1946 and July 2015 of the association between ambient air pollution and parameters of heart rate variability reflecting autonomic nervous function. We focused on exposure to mass concentrations of fine particles (PM2.5), nitrogen dioxide (NO2), and ozone (O3), and four commonly used indices of heart rate variability (HRV): standard deviation of all normal-to-normal intervals (SDNN); root mean square of successive differences in adjacent normal-to-normal intervals (RMSSD); high frequency power (HF); and low frequency power (LF). We searched bibliographic databases and references of identified articles and abstracted characteristics of their design and conduct, and synthesized the quantitative findings in graphic form according to health condition of the study population and the functional form of the HRV indices used in the regression analyses.

RESULTS

A total of 33 panel studies were included: 31, 12, and 13 studies were used to investigate ambient exposure to PM2.5, NO2 and O3, respectively. We found substantial variation across studies in terms of design characteristics and statistical methodologies, and we identified some studies that may have had methodological and statistical issues. Because many panel studies were not comparable to each other, meta-analyses were not generally possible, although we were able to pool the results obtained amongst older adults who had cardiovascular disease for the 24-h average concentrations of PM2.5 prior to the heart rate variability measurements. In studies of PM2.5 among older adults with cardiovascular disease, logarithmic transformations of the HRV indices were used in ten studies. Negative associations across all HRV indices were found in 60-86% of these studies for periods of exposures ranging from 5-min to 5-days. The pooled percent changes for an increase of 10μg/m(3) in the 24-h prior to the measurements of HRV were: -2.11% for SDNN (95% confidence interval (95%CI): -4.00, -0.23%), -3.29% for RMSSD (95%CI: -6.32, -0.25%), -4.76% for LF (95%CI: -12.10, 2.58%), and -1.74% for HF (95%CI: -7.79, 4.31%). No transformations were used in seven studies of PM2.5 among older adults with cardiovascular disease, and we found for absolute differences pooled changes in the HRV indices, for an increase of 10μg/m(3), of -0.31ms for SDNN (95%CI: -1.02, 0.41ms) and -1.22ms for RMSSD (95%CI: -2.37; -0.07ms). For gaseous pollutants, negative associations over periods of exposure ranging from 5-min or to 5-days prior to the heart rate variability measurements were reported in 71-83% of studies of NO2 and 57-100% of studies of O3, depending of the indices of heart rate variability. However, many of these studies had statistical or methodological issues, and in the few studies without these issues the confidence intervals were relatively wide and mostly included the null.

CONCLUSIONS AND DISCUSSION

We were not persuaded by the results that there was an association between PM2.5 and any of the four indices of heart rate variability. For NO2 and O3 the number of high-quality studies was insufficient to draw any definite conclusions. Further panel studies with improved design and methodologies are needed to help establish or refute an association between ambient exposure to air pollution and heart rate variability.

Association of EGF Receptor and NLRs signaling with Cardiac Inflammation and Fibrosis in Mice Exposed to Fine Particulate Matter

ЄAmbient fine particulate matter (PM2.5 ) could induce cardiovascular diseases (CVD), but the mechanism remains unknown. To investigate the roles of epidermal growth factor receptor (EGFR) and NOD-like receptors (NLRs) in PM2.5 -induced cardiac injury, we set up a BALB/c mice model of PM2.5 -induced cardiac inflammation and fibrosis with intratracheal instillation of PM2.5 suspension (4.0 mg/kg b.w.) for 5 consecutive days (once per day). After exposure, we found that mRNA levels of CXCL1, interleukin (IL)-6, and IL-18 were elevated, but interestingly, mRNA level of NLRP12 was significant decreased in heart tissue from PM2.5 -induced mice compared with those of saline-treated mice using real-time PCR. Protein levels of phospho-EGFR (Tyr1068), phospho-Akt (Thr308), NLRP3, NF-κB-p52/p100, and NF-κB-p65 in heart tissue of PM2.5 -exposed mice were all significantly increased using immunohistochemistry or Western blotting. Therefore, PM2.5 exposure could induce cardiac inflammatory injury in mice, which may be involved with EGFR/Akt signaling, NLRP3, and NLRP12.

Ambient particulate matter and microRNAs in extracellular vesicles: a pilot study of older individuals

Background

Air pollution from particulate matter (PM) has been linked to cardiovascular morbidity and mortality; however the underlying biological mechanisms remain to be uncovered. Gene regulation by microRNAs (miRNAs) that are transferred between cells by extracellular vesicles (EVs) may play an important role in PM-induced cardiovascular risk. This study sought to determine if ambient PM_2.5 levels are associated with expression of EV-encapsulated miRNAs (evmiRNAs), and to investigate the participation of such evmiRNAs in pathways related to cardiovascular disease (CVD).

Methods

We estimated the short- (1-day), intermediate- (1-week and 1-month) and long-term (3-month, 6-month, and 1-year) moving averages of ambient PM_2.5 levels at participants’ addresses using a validated hybrid spatio-temporal land-use regression model. We collected 42 serum samples from 22 randomly selected participants in the Normative Aging Study cohort and screened for 800 miRNAs using the NanoString nCounter® platform. Mixed effects regression models, adjusted for potential confounders were used to assess the association between ambient PM_2.5 levels and evmiRNAs. All p-values were adjusted for multiple comparisons. In-silico Ingenuity Pathway Analysis (IPA) was performed to identify biological pathways that are regulated by PM-associated evmiRNAs.

Results

We found a significant association between long-term ambient PM_2.5 exposures and levels of multiple evmiRNAs circulating in serum. In the 6-month window, ambient PM_2.5 exposures were associated with increased levels of miR-126-3p (0.74 ± 0.21; p = 0.02), miR-19b-3p (0.52 ± 0.15; p = 0.02), miR-93-5p (0.78 ± 0.22; p = 0.02), miR-223-3p (0.74 ± 0.22; p = 0.02), and miR-142-3p (0.81 ± 0.21; p = 0.03). Similarly, in the 1-year window, ambient PM_2.5 levels were associated with increased levels of miR-23a-3p (0.83 ± 0.23; p = 0.02), miR-150-5p (0.90 ± 0.24; p = 0.02), miR-15a-5p (0.70 ± 0.21; p = 0.02), miR-191-5p (1.20 ± 0.35; p = 0.02), and let-7a-5p (1.42 ± 0.39; p = 0.02). In silico pathway analysis on PM_2.5-associated evmiRNAs identified several key CVD-related pathways including oxidative stress, inflammation, and atherosclerosis.

Conclusions

We found an association between long-term ambient PM_2.5 levels and increased levels of evmiRNAs circulating in serum. Further observational studies are warranted to confirm and extend these important findings in larger and more diverse populations, and experimental studies are needed to elucidate the exact roles of evmiRNAs in PM-induced CVD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12989-016-0121-0) contains supplementary material, which is available to authorized users.

The biological effects upon the cardiovascular system consequent to exposure to particulates of less than 500 nm in size

CONTEXT

Ultrafine particulate matter contribution to cardiovascular disease is not known and not regulated. PM up to 500 nm are abundant in urban air and alveolar deposition is significant.

OBJECTIVE

Effects beyond the alveolar barrier within the body or in vitro tissues exposed to particles <500 nm.

METHODS AND RESULTS

DATABASES

MEDLINE; Ovid-MEDLINE PREM; Web of Science; PubMed (SciGlobe). 127 articles. Results in tables: "subject type exposed", "exposure type", "technique".

CONCLUSION

Heart rate, vasoactivity, atherosclerotic advancement, oxidative stress, coagulability, inflammatory changes are affected. Production of reactive oxygen species is a useful target to limit outcomes associated with UFP exposure.

Cardiac and mitochondrial dysfunction following acute pulmonary exposure to mountaintop removal mining particulate matter

Throughout the United States, air pollution correlates with adverse health outcomes, and cardiovascular disease incidence is commonly increased following environmental exposure. In areas surrounding active mountaintop removal mines (MTM), a further increase in cardiovascular morbidity is observed and may be attributed in part to particulate matter (PM) released from the mine. The mitochondrion has been shown to be central in the etiology of many cardiovascular diseases, yet its roles in PM-related cardiovascular effects are not realized. In this study, we sought to elucidate the cardiac processes that are disrupted following exposure to mountaintop removal mining particulate matter (PM MTM). To address this question, we exposed male Sprague-Dawley rats to PM MTM, collected within one mile of an active MTM site, using intratracheal instillation. Twenty-four hours following exposure, we evaluated cardiac function, apoptotic indices, and mitochondrial function. PM MTM exposure elicited a significant decrease in ejection fraction and fractional shortening compared with controls. Investigation into the cellular impacts of PM MTM exposure identified a significant increase in mitochondrial-induced apoptotic signaling, as reflected by an increase in TUNEL-positive nuclei and increased caspase-3 and -9 activities. Finally, a significant increase in mitochondrial transition pore opening leading to decreased mitochondrial function was identified following exposure. In conclusion, our data suggest that pulmonary exposure to PM MTM increases cardiac mitochondrial-associated apoptotic signaling and decreases mitochondrial function concomitant with decreased cardiac function. These results suggest that increased cardiovascular disease incidence in populations surrounding MTM mines may be associated with increased cardiac cell apoptotic signaling and decreased mitochondrial function.

Cardiopulmonary benefits of reducing indoor particles of outdoor origin: a randomized, double-blind crossover trial of air purifiers

BACKGROUND

Indoor exposure to fine particulate matter (PM2.5) from outdoor sources is a major health concern, especially in highly polluted developing countries such as China. Few studies have evaluated the effectiveness of indoor air purification on the improvement of cardiopulmonary health in these areas.

OBJECTIVES

This study sought to evaluate whether a short-term indoor air purifier intervention improves cardiopulmonary health.

METHODS

We conducted a randomized, double-blind crossover trial among 35 healthy college students in Shanghai, China, in 2014. These students lived in dormitories that were randomized into 2 groups and alternated the use of true or sham air purifiers for 48 h with a 2-week washout interval. We measured 14 circulating biomarkers of inflammation, coagulation, and vasoconstriction; lung function; blood pressure (BP); and fractional exhaled nitric. We applied linear mixed-effect models to evaluate the effect of the intervention on health outcome variables.

RESULTS

On average, air purification resulted in a 57% reduction in PM2.5 concentration, from 96.2 to 41.3 μg/m3, within hours of operation. Air purification was significantly associated with decreases in geometric means of several circulating inflammatory and thrombogenic biomarkers, including 17.5% in monocyte chemoattractant protein-1, 68.1% in interleukin-1β, 32.8% in myeloperoxidase, and 64.9% in soluble CD40 ligand. Furthermore, systolic BP, diastolic BP, and fractional exhaled nitrous oxide were significantly decreased by 2.7%, 4.8%, and 17.0% in geometric mean, respectively. The impacts on lung function and vasoconstriction biomarkers were beneficial but not statistically significant.

CONCLUSIONS

This intervention study demonstrated clear cardiopulmonary benefits of indoor air purification among young, healthy adults in a Chinese city with severe ambient particulate air pollution. (Intervention Study on the Health Impact of Air Filters in Chinese Adults; NCT02239744).

Beyond the Mean: Quantile Regression to Explore the Association of Air Pollution with Gene-Specific Methylation in the Normative Aging Study

BACKGROUND

Air pollution has been related to mean changes in outcomes, including DNA methylation. However, mean regression analyses may not capture associations that occur primarily in the tails of the outcome distribution.

OBJECTIVES

In this study, we examined whether the association between particulate air pollution and DNA methylation differs across quantiles of the methylation distribution. We focused on methylation of candidate genes related to coagulation and inflammation: coagulation factor III (F3), intercellular adhesion molecule 1 (ICAM-1), interferon gamma (IFN-γ), interleukin-6 (IL-6), and toll-like receptor 2 (TRL-2).

METHODS

We measured gene-specific blood DNA methylation repeatedly in 777 elderly men participating in the Normative Aging Study (1999-2010). We fit quantile regressions for longitudinal data to investigate whether the associations of particle number, PM2.5 (diameter ≤ 2.5 μm)black carbon, and PM2.5 mass concentrations (4-week moving average) with DNA methylation [expressed as the percentage of methylated cytosines over the sum of methylated and unmethylated cytosines at position 5 (%5mC)] varied across deciles of the methylation distribution. We reported the quantile regression coefficients that corresponded to absolute differences in DNA methylation (expressed in %5mC) associated with an interquartile range increase in air pollution concentration.

RESULTS

Interquartile range increases in particle number, PM2.5 black carbon, and PM2.5 mass concentrations were associated with significantly lower methylation in the lower tails of the IFN-γ and ICAM-1 methylation distributions. For instance, a 3.4-μg/m3 increase in PM2.5 mass concentration was associated with a 0.18%5mC (95% CI: -0.30, -0.06) decrease on the 20th percentile of ICAM-1 methylation, but was not significantly related to the 80th percentile (estimate: 0.07%5mC, 95% CI: -0.09, 0.24).

CONCLUSIONS

In our study population of older men, air pollution exposures were associated with a left shift in the lower tails of the IFN-γ and ICAM-1 methylation distributions.

Particulate air pollution and circulating biomarkers among type 2 diabetic mellitus patients: the roles of particle size and time windows of exposure

BACKGROUND

Short-term associations between size-fractionated particulate matter (PM) air pollution and circulating biomarkers are not well established, especially among diabetes patients.

METHODS

We conducted a longitudinal panel study involving 6 repeated measurements of 12 circulating biomarkers among 35 diabetes patients from April to June, 2013 in Shanghai, China. Real-time number and mass concentrations of PM with multiple size fractions between 0.25 and 10 μm were measured. Linear mixed-effect models were used to explore the associations between size-fractionated PM concentrations and blood biomarkers at different time windows.

RESULTS

Short-term exposure to PM was significantly associated with elevated levels of 5 biomarkers of inflammation, 3 biomarkers of coagulation and 1 vasoconstrictor. The effects varied considerably by particle size and time windows. Overall, PM with smaller size had stronger associations, and the most significant size fractions were 0.25-0.40 μm. Even 2 h exposure to PM can lead to a significant increase in biomarkers. The effects on biomarkers of inflammation and vasoconstriction were restricted to the first 12h after exposure, but the effects on coagulation persisted for 24-72 h. For example, an interquartile range increase in 2h average exposure to PM(0.25-0.40) was associated with 6-20% increase in biomarkers of inflammation, 19-38% in coagulation and 17% in vasoconstriction. PM had a stronger effect among male patients than female patients.

CONCLUSIONS

Our results provided important evidence on the roles of the size and time windows of exposure in the PM-mediated effects on circulating biomarkers of inflammation, coagulation and vasoconstriction in diabetes patients in China.