Cardiac autonomic dysfunction: effects from particulate air pollution and protection by dietary methyl nutrients and metabolic polymorphisms

PM2.5-mediated cardiovascular disease in aging: Cardiometabolic risks, molecular mechanisms and potential interventions

Air pollution, particularly fine particulate matter (PM2.5) with <2.5 μm in diameter, is a major public health concern. Studies have consistently linked PM2.5 exposure to a heightened risk of cardiovascular diseases (CVDs) such as ischemic heart disease (IHD), heart failure (HF), and cardiac arrhythmias. Notably, individuals with pre-existing age-related cardiometabolic conditions appear more susceptible. However, the specific impact of PM2.5 on CVDs susceptibility in older adults remains unclear. Therefore, this review addresses this gap by discussing the factors that make the elderly more vulnerable to PM2.5-induced CVDs. Accordingly, we focused on physiological aging, increased susceptibility, cardiometabolic risk factors, CVDs, and biological mechanisms. This review concludes by examining potential interventions to reduce exposure and the adverse health effects of PM2.5 in the elderly population. The latter includes dietary modifications, medications, and exploration of the potential benefits of supplements. By comprehensively analyzing these factors, this review aims to provide a deeper understanding of the detrimental effects of PM2.5 on cardiovascular health in older adults. This knowledge can inform future research and guide strategies to protect vulnerable populations from the adverse effects of air pollution.

Amelioration of metabolic disorders in H9C2 cardiomyocytes induced by PM2.5 treated with vitamin C

OBJECTIVE

Particulate matter with an aerodynamic diameter ≤2.5 μm (PM2.5) is a public health risk. We investigate PM2.5 on metabolites in cardiomyocytes and the influence of vitamin C on PM2.5 toxicity.

MATERIALS AND METHODS

For 24 hours, H9C2 were exposed to various concentrations of PM2.5 (0, 100, 200, 400, 800 μg/ml), after which the levels of reactive oxygen species (ROS) and cell viability were measured using the cell counting kit-8 (CCK-8) and 2',7'-dichlorofluoresceindiacetate (DCFH2-DA), respectively. H9C2 were treated with PM2.5 (200 μg/ml) in the presence or absence of vitamin C (40 μmol/L). mRNA levels of interleukin 6(IL-6), caspase-3, fatty acid-binding protein 3 (FABP3), and hemeoxygenase-1 (HO-1) were investigated by quantitative reverse-transcription polymerase chain reaction. Non-targeted metabolomics by LC-MS/MS was applied to evaluate the metabolic profile in the cell.

RESULTS

Results revealed a concentration-dependent reduction in cell viability, death, ROS, and increased expression of caspase-3, FABP3, and IL-6. In total, 15 metabolites exhibited significant differential expression (FC > 2, p < 0.05) between the control and PM2.5 group. In the PM2.5 group, lysophosphatidylcholines (LysoPC,3/3) were upregulated, whereas amino acids (5/5), amino acid analogues (3/3), and other acids and derivatives (4/4) were downregulated. PM2.5 toxicity was lessened by vitamin C. It reduced PM2.5-induced elevation of LysoPC (16:0), LysoPC (16:1), and LysoPC (18:1).

DISCUSSION AND CONCLUSIONS

PM2.5 induces metabolic disorders in H9C2 cardiomyocytes that can be ameliorated by treatment with vitamin C.

Joint effect of ambient PM2.5 exposure and vitamin B12 during pregnancy on the risk of gestational diabetes mellitus

BACKGROUND

Evidence has indicated that the risk of gestational diabetes mellitus (GDM) was linked to PM_2.5 exposure during pregnancy, but findings on susceptible exposure windows are inconsistent. Further, previous studies have not paid attention to B₁₂ intake in the relationship between PM_2.5 exposure and GDM. The study is aimed to identify the strength and exposure periods for associations of PM_2.5 exposure with GDM, followed by exploring the potential interplay of gestational B₁₂ levels and PM_2.5 exposure on the risk of GDM.

METHODS

The participants were recruited in a birth cohort between 2017 and 2018, and 1396 eligible pregnant women who completed a 75-g oral glucose tolerance test (OGTT) were included. Prenatal PM_2.5 concentrations were estimated using an established spatiotemporal model. Logistic and linear regression analyses were used to test associations of gestational PM_2.5 exposure with GDM and OGTT-glucose levels, respectively. The joint associations of gestational PM_2.5 exposure and B₁₂ level on GDM were examined under crossed exposure combinations of PM_2.5 (high versus low) and B₁₂ (insufficient versus sufficient).

RESULTS

In the 1396 pregnant women, the median levels of PM_2.5 exposure during the 12 weeks before pregnancy, the 1st trimester, and the 2nd trimesters were 59.33 μg/m³, 63.44 μg/m³, and 64.39 μg/m³, respectively. The risk of GDM was significantly associated with a 10 μg/m³ increase of PM_2.5 during the 2nd trimester (RR = 1.44, 95 % CI: 1.01, 2.04). The percentage change in fasting glucose was also associated with PM_2.5 exposure during the 2nd trimester. A higher risk of GDM was observed among women with high PM_2.5 exposure and insufficient B₁₂ levels than those with low PM_2.5 and sufficient B₁₂.

CONCLUSION

The study supported higher PM_2.5 exposure during the 2nd trimester is significantly associated with GDM risk. It first highlighted insufficient B₁₂ status might enhance adverse effects of air pollution on GDM.

MTHFR epigenetic derepression protects against diabetes cardiac fibrosis

BACKGROUND

Diabetes cardiac fibrosis is associated with altered DNA methylation of fibrogenic genes; however, the underlying mechanisms remain unclear.

OBJECTIVES

In this study, we investigate the critical role of DNA methylation aberration-associated suppression of MTHFR in diabetes cardiac fibrosis, and the protective effects of folate on diabetes cardiac fibrosis, using cultured cells, animal models, and clinical samples.

METHODS AND RESULTS

Herein, we report that DNA methylation repression of MTHFR, critically involved in diabetes cardiac fibrosis, mediates the significant protective effects of folate in a mouse model of diabetes cardiac fibrosis induced by STZ. Heart MTHFR expression was markedly suppressed in diabetes cardiac fibrosis patients and mice, accompanied by increased DNMT3A and MTHFR promoter methylation. Knockdown of DNMT3A demethylated MTHFR promoter, recovered the MTHFR loss, and alleviated the diabetes cardiac fibrosis pathology and cardiac fibroblasts pyroptosis. Mechanistically, DNMT3A epigenetically repressed MTHFR expression via methylation of the promoter. Interestingly, folate supplementation can rescue the effect of MTHFR loss in diabetes cardiac fibrosis, suggesting that inactivation of MTHFR through epigenetics is a critical mediator of diabetes cardiac fibrosis.

CONCLUSIONS

The current study identifies that MTHFR repression due to aberrant DNMT3A elevation and subsequent MTHFR promoter hypermethylation is likely an important epigenetic feature of diabetes cardiac fibrosis, and folate supplementation protects against diabetes cardiac fibrosis.

Association between global DNA methylation (LINE-1) and occupational particulate matter exposure among informal electronic-waste recyclers in Ghana

This study examined the associations between PM (2.5 and 10) and global DNA methylation among 100 e-waste workers and 51 non-e-waste workers serving as controls. Long interspersed nucleotide repetitive elements-1 (LINE-1) was measured by pyrosequencing. Personal PM_2.5 and PM₁₀ were measured over a 4-hour work-shift using real-time particulate monitors incorporated into a backpack . Linear regression models were used to assess the association between PM and LINE-1 DNA methylation. The concentrations of PM_2.5 and PM₁₀ were significantly higher among the e-waste workers than the controls (77.32 vs 34.88, p < 0.001 and 210.21 vs 121.92, p < 0.001, respectively). PM_2.5 exposure was associated with increased LINE-1 CpG2 DNA methylation (β = 0.003; 95% CI; 0.001, 0.006; p = 0.022) but not with the average of all 4 CpG sites of LINE-1. In summary, high levels of PM_2.5 exposure was associated with increased levels of global DNA methylation in a site-specific manner.

Combined Associations of Physical Activity and Particulate Matter With Subsequent Cardiovascular Disease Risk Among 5‐Year Cancer Survivors

Background

The combined associations of physical activity and particulate matter (PM) with subsequent cardiovascular disease (CVD) risk is yet unclear.

Methods and Results

The study population consisted of 18 846 cancer survivors who survived for at least 5 years after initial cancer diagnosis from the Korean National Health Insurance Service database. Average PM levels for 4 years were determined in administrative district areas, and moderate‐to‐vigorous physical activity (MVPA) information was acquired from health examination questionnaires. A multivariable Cox proportional hazards model was used to evaluate the risk for CVD. Among patients with low PM with particles ≤2.5 µm (PM2.5; (19.8–25.6 μg/m³) exposure, ≥5 times per week of MVPA was associated with lower CVD risk (adjusted hazard ratio [aHR], 0.77; 95% CI, 0.60–0.99) compared with 0 times per week of MVPA. Also, a higher level of MVPA frequency was associated with lower CVD risk (P for trend=0.028) among cancer survivors who were exposed to low PM2.5 levels. In contrast, ≥5 times per week of MVPA among patients with high PM2.5 (25.8–33.8 μg/m³) exposure was not associated with lower CVD risk (aHR, 0.98; 95% CI, 0.79–1.21). Compared with patients with low PM2.5 and MVPA ≥3 times per week, low PM2.5 and MVPA ≤2 times per week (aHR, 1.26; 95% CI, 1.03–1.55), high PM2.5 and MVPA ≥3 times per week (aHR, 1.34; 95% CI, 1.07–1.67), and high PM2.5 and MVPA ≤2 times per week (aHR, 1.38; 95% CI, 1.12–1.70) was associated with higher CVD risk.

Conclusions

Cancer survivors who engaged in MVPA ≥5 times per week benefited from lower CVD risk upon low PM2.5 exposure. High levels of PM2.5 exposure may attenuate the risk‐reducing effects of MVPA on the risk of CVD.

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

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

Association of Particulate Matter from Cooking Oil Fumes with Heart Rate Variability and Oxidative Stress

Many studies have reported various cardiovascular autonomic responses to ambient particulate matter (PM) pollution, but few have reported such responses to occupational PM exposures. Even fewer have demonstrated a relationship between PM pollution and oxidative stress in humans. This panel study evaluates the association between occupational exposure to PM in cooking oil fumes (COFs), and changes in both heart rate variability (HRV) and oxidative stress responses in 54 male Chinese cooks. Linear mixed-effects regression models were adopted to estimate the strength of the association between PM and HRV. Participants' pre- and post-workshift urine samples were analyzed for 8-hydroxy-2'-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). Exposure to PM in COFs from 15 min to 2 h were associated with a decrease in HRV and an increase in heart rate among cooks. The urinary 8-OHdG levels of cooks were significantly elevated after workshift exposure to COFs. The levels of PM2.5, PM1.0, and particulate benzo(a)pyrene in COFs were all positively correlated with cross-workshift urinary 8-OHdG levels. Furthermore, the levels of benzo(a)pyrene in COFs were positively correlated with cross-workshift urinary MDA levels. The effects of COFs on HRV were independent of cross-workshift urinary 8-OHdG levels. Exposure to COFs leads to disturbed autonomic function and an increased risk of oxidative DNA injury among cooks in Chinese restaurants.

Application of high-resolution metabolomics to identify biological pathways perturbed by traffic-related air pollution

BACKGROUND

Substantial research has investigated the adverse effects of traffic-related air pollutants (TRAP) on human health. Convincing associations between TRAP and respiratory and cardiovascular diseases are known, but the underlying biological mechanisms are not well established. High-resolution metabolomics (HRM) is a promising platform for untargeted characterization of molecular mechanisms between TRAP and health indexes.

OBJECTIVES

We examined metabolic perturbations associated with short-term exposures to TRAP, including carbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), fine particulate matter (PM2.5), organic carbon (OC), and elemental carbon (EC) among 180 participants of the Center for Health Discovery and Well-Being (CHDWB), a cohort of Emory University-affiliated employees.

METHODS

A cross-sectional study was conducted on baseline visits of 180 CHDWB participants enrolled during 2008-2012, in whom HRM profiling was determined in plasma samples using liquid chromatography-high-resolution mass spectrometry with positive and negative electrospray ionization (ESI) modes. Ambient pollution concentrations were measured at an ambient monitor near downtown Atlanta. Metabolic perturbations associated with TRAP exposures were assessed following an untargeted metabolome-wide association study (MWAS) framework using feature-specific Tobit regression models, followed by enriched pathway analysis and chemical annotation.

RESULTS

Subjects were predominantly white (76.1%) and non-smokers (95.6%), and all had at least a high school education. In total, 7821 and 4123 metabolic features were extracted from the plasma samples by the negative and positive ESI runs, respectively. There are 3421 features significantly associated with at least one air pollutant by negative ion mode, and 1691 features by positive ion mode. Biological pathways enriched by features associated with the pollutants are primarily involved in nucleic acids damage/repair (e.g., pyrimidine metabolism), nutrient metabolism (e.g., fatty acid metabolism), and acute inflammation (e.g., histidine metabolism and tyrosine metabolism). NO2 and EC were associated most consistently with these pathways. We confirmed the chemical identity of 8 metabolic features in negative ESI and 2 features in positive ESI, including metabolites closely linked to oxidative stress and inflammation, such as histamine, tyrosine, tryptophan, and proline.

CONCLUSIONS

We identified a range of ambient pollutants, including components of TRAP, associated with differences in the metabolic phenotype among the cohort of 180 subjects. We found Tobit models to be a robust approach to handle missing data among the metabolic features. The results were encouraging of further use of HRM and MWAS approaches for characterizing molecular mechanisms underlying exposure to TRAP.

Long-Term PM2.5 Exposure and Risks of Ischemic Heart Disease and Stroke Events: Review and Meta-Analysis

Background

Fine particulate matter <2.5 µm in diameter (PM_2.5) has known effects on cardiovascular morbidity and mortality. However, no study has quantified and compared the risks of incident myocardial infarction, incident stroke, ischemic heart disease (IHD) mortality, and cerebrovascular mortality in relation to long‐term PM_2.5 exposure.

Methods and Results

We sought to quantitatively summarize studies of long‐term PM_2.5 exposure and risk of IHD and stroke events by conducting a review and meta‐analysis of studies published by December 31, 2019. The main outcomes were myocardial infarction, stroke, IHD mortality, and cerebrovascular mortality. Random effects meta‐analyses were used to estimate the combined risk of each outcome among studies. We reviewed 69 studies and included 42 studies in the meta‐analyses. In meta‐analyses, we found that a 10‐µg/m³ increase in long‐term PM_2.5 exposure was associated with an increased risk of 23% for IHD mortality (95% CI, 15%–31%), 24% for cerebrovascular mortality (95% CI, 13%–36%), 13% for incident stroke (95% CI, 11%–15%), and 8% for incident myocardial infarction (95% CI, −1% to 18%). There were an insufficient number of studies of recurrent stroke and recurrent myocardial infarction to conduct meta‐analyses.

Conclusions

Long‐term PM_2.5 exposure is associated with increased risks of IHD mortality, cerebrovascular mortality, and incident stroke. The relationship with incident myocardial infarction is suggestive of increased risk but not conclusive. More research is needed to understand the relationship with recurrent events.

Folic Acid Supplementation and the Association between Maternal Airborne Particulate Matter Exposure and Preterm Delivery: A National Birth Cohort Study in China

BACKGROUND

Potential modification of the association between maternal particulate matter (PM) exposure and preterm delivery (PTD) by folic acid (FA) supplementation has not been studied.

OBJECTIVE

We examined whether FA supplementation could reduce the risk of PTD associated with maternal exposure to PM in ambient air during pregnancy.

METHOD

In a cohort study covering 30 of the 31 provinces of mainland China in 2014, 1,229,556 primiparas of Han ethnicity were followed until labor. We collected information on their FA supplementation and pregnancy outcomes and estimated each participant's exposure to PM with diameters of ≤ 10 μ m (PM 10 ), 2.5 μ m (PM 2.5 ), and 1 μ m (PM 1 ) using satellite remote-sensing based models. Cox proportional hazard regression models were used to examine interactions between FA supplementation and PM exposures, after controlling for individual characteristics.

RESULTS

Participants who initiated FA ≥ 3  months prior to pregnancy (38.1%) had a 23% [hazard ratio ( HR ) = 0.77 (95% CI: 0.76, 0.78)] lower risk of PTD than women who did not use preconception FA. Participants with PM concentrations in the highest quartile had a higher risk of PTD [HR = 1.29 (95% CI: 1.26, 1.32) for PM 1 , 1.52 (95% CI: 1.46, 1.58) for PM 2.5 , and 1.22 (95% CI: 1.17, 1.27) for PM 10 ] than those with exposures in the lowest PM quartiles. Estimated associations with a 10 - μ g / m 3 increase in PM 1 and PM 2.5 were significantly lower among women who initiated FA ≥ 3  months prior to pregnancy [HR = 1.09 (95% CI: 1.08, 1.10) for both exposures] than among women who did not use preconception FA [HR = 1.12 (95% CI: 1.11, 1.13) for both exposures; p interaction < 0.001 ]. The corresponding association was also significantly lower for a 10 - μ g / m 3 increase in PM 10 [HR = 1.03 (95% CI: 1.02, 1.03) for FA ≥ 3  months before pregnancy vs. 1.04 (95% CI: 1.03, 1.04) for no preconception FA; p interaction < 0.001 ].

CONCLUSION

Our findings require confirmation in other populations, but they suggest that initiating FA supplementation ≥ 3  months prior to pregnancy may lessen the risk of PTD associated with PM exposure during pregnancy among primiparas of Han ethnicity. https://doi.org/10.1289/EHP6386.

The environment as a determinant of successful aging or frailty

The number of elderly persons is rising rapidly, and healthspan is a key factor in determining the well-being of individuals and the sustainability of national health systems. Environmental health is crucial for a "successful aging". Complex relationships between environmental factors and non-communicable diseases play a major role, causing or accelerating disabilities. Besides genetic factors, aging results from the concurrence of several environmental factors starting from early (i.e. in utero) life, able to increase susceptibility to diseases in adulthood, and to promote frailty in the elderly. In aged people, an unhealthy environment contributes to a fast and early decline and increases vulnerability. Exposure to pollutants facilitates the onset and progression of cardiovascular, respiratory, metabolic and neurologic diseases through direct effects and epigenetic mechanisms negatively affecting biological age. Healthy diet, healthy environment and constant physical activity could counteract, at least in part, the negative effects of environmental stressors. Almost all environmental factors generating detrimental effects on aging are modifiable, with relevant implications in terms of primary prevention measures potentially leading to decreased frailty, to an increase in the number of years lived without diseases or disability, and to a significant reduction in health expenditure.

Oxidative stress and the cardiovascular effects of air pollution

Cardiovascular causes have been estimated to be responsible for more than two thirds of the considerable mortality attributed to air pollution. There is now a substantial body of research demonstrating that exposure to air pollution has many detrimental effects throughout the cardiovascular system. Multiple biological mechanisms are responsible, however, oxidative stress is a prominent observation at many levels of the cardiovascular impairment induced by pollutant exposure. This review provides an overview of the evidence that oxidative stress is a key pathway for the different cardiovascular actions of air pollution.

Diet, Secondhand Smoke, and Glycated Hemoglobin (HbA1c) Levels among Singapore Chinese Adults

The combination of poor diet and exposure to secondhand smoke may increase hemoglobin A1c (HbA1c) levels, but few studies have explored this interaction. We explored an interaction among 574 never-smoking adults from the Singapore Chinese Health Study. At baseline (age 59 ± 8 years), intakes of omega-3 polyunsaturated fatty acids, vitamin C, vitamin E and fiber were estimated using a modified food frequency questionnaire. At follow-up (age 64 ± 9 years), HbA1c and cotinine were measured. A product term between cotinine (above or below the median value) and each nutrient (high or low intake) was included in separate linear regression models with HbA1c as the outcome. HbA1c among those with high cotinine and low omega-3 polyunsaturated fatty acids intakes were higher than would be expected due to the individual effects alone (p-for-interaction = 0.05). Among those with lower intakes of omega-3 polyunsaturated fatty acids, high cotinine levels were associated with 0.54% higher HbA1c levels (95% confidence interval [CI]: 0.02, 1.06). Conversely, among those with higher intakes of omega-3 polyunsaturated fatty acids, HbA1c differ not differ by exposure (−0.09%; 95% CI: −0.45, 0.30). No evidence of interaction was observed for other nutrients. Diets high in omega-3 polyunsaturated fatty acids may ameliorate secondhand smoke-induced increases in HbA1c.

Inhibitory Effects of Black Ginseng on Particulate Matter-Induced Pulmonary Injury

Inhalation of fine particulate matter (PM2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. Black ginseng (BG), steamed and dried ginseng nine times, exhibits various pharmacological activities such as antibacterial, antihyperglycemic, anti-atopic, antibacterial, and anti-inflammatory activities. In this study, we investigated the beneficial effects of black ginseng extract (BGE) against PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM2.5-treated ECs and mice. BGE significantly scavenged PM2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase (MAPK). Concurrently, BGE activated Akt, which helped maintain endothelial integrity. Furthermore, BGE reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid in PM-induced lung tissues. These results indicated that BGE may exhibit protective effects against PM-induced inflammatory lung injury and vascular hyperpermeability.

Inhibitory effects of collismycin C and pyrisulfoxin A on particulate matter-induced pulmonary injury

BACKGROUND

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. Marine microbial natural products isolated from microbial culture broths were screened for pulmonary protective effects against PM_2.5. Two 2,2'-bipyridine compounds isolated from a red alga-associated Streptomyces sp. MC025-collismycin C (2) and pyrisulfoxin A (5)-were found to inhibit PM_2.5-mediated vascular barrier disruption.

PURPOSE

To confirm the inhibitory effects of collismycin C and pyrisulfoxin A on PM_2.5-induced pulmonary injury STUDY DESIGN: In this study, we investigated the beneficial effects of collismycin C and pyrisulfoxin A on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation.

METHODS

Permeability, leukocyte migration, proinflammatory protein activation, reactive oxygen species (ROS) generation, and histology were evaluated in PM_2.5-treated ECs and mice.

RESULTS

Collismycin C and pyrisulfoxin A significantly scavenged PM_2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase as well as activated Akt, which helped in maintaining endothelial integrity, in purified pulmonary endothelial cells. Furthermore, collismycin C and pyrisulfoxin A reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in the bronchoalveolar lavage fluid of PM-treated mice.

CONCLUSION

These data suggested that collismycin C and pyrisulfoxin A might exert protective effects on PM-induced inflammatory lung injury and vascular hyperpermeability.

Inhibitory effects of Kyung-Ok-Ko, traditional herbal prescription, on particulate matter-induced vascular barrier disruptive responses

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury caused by the loss of vascular barrier integrity. A traditional herbal prescription, Kyung-Ok-Ko (KOK), has long been used in Oriental medicine as a tonic for age-related diseases. In this study, we investigated the beneficial effects of KOK on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated EC and mice. KOK significantly scavenged PM_2.5-induced ROS and inhibited the ROS-induced activation of p38 mitogen-activated protein kinase (MAPK). Concurrently, KOK activated Akt, which helped maintain endothelial integrity. Furthermore, KOK reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in bronchoalveolar lavage fluids in PM-induced lung tissues. These data suggested that KOK might exhibit protective effects in PM-induced inflammatory lung injury and vascular hyperpermeability.

Exposure to outdoor air pollution and its human health outcomes: A scoping review

Despite considerable air pollution prevention and control measures that have been put into practice in recent years, outdoor air pollution remains one of the most important risk factors for health outcomes. To identify the potential research gaps, we conducted a scoping review focused on health outcomes affected by outdoor air pollution across the broad research area. Of the 5759 potentially relevant studies, 799 were included in the final analysis. The included studies showed an increasing publication trend from 1992 to 2008, and most of the studies were conducted in Asia, Europe, and North America. Among the eight categorized health outcomes, asthma (category: respiratory diseases) and mortality (category: health records) were the most common ones. Adverse health outcomes involving respiratory diseases among children accounted for the largest group. Out of the total included studies, 95.2% reported at least one statistically positive result, and only 0.4% showed ambiguous results. Based on our study, we suggest that the time frame of the included studies, their disease definitions, and the measurement of personal exposure to outdoor air pollution should be taken into consideration in any future research. The main limitation of this study is its potential language bias, since only English publications were included. In conclusion, this scoping review provides researchers and policy decision makers with evidence taken from multiple disciplines to show the increasing prevalence of outdoor air pollution and its adverse effects on health outcomes.

Association of long-term exposure to traffic-related PM10 with heart rate variability and heart rate dynamics in healthy subjects

BACKGROUND

Epidemiological evidence on the influence of long-term exposure to traffic-related particulate matter (TPM₁₀) on heart rate variability (HRV) is weak.

OBJECTIVE

To evaluate the association of long-term exposure (10 years) with TPM₁₀ on the regulation of the autonomic cardiovascular system and heart rate dynamics (HRD) in an aging general population, as well as potential modifying effects by the a priori selected factors sex, smoking status, obesity, and gene variation in selected glutathione S-transferases (GSTs).

METHODS

We analyzed data from 1593 SAPALDIA cohort participants aged ≥ 50 years. For each participant, various HRV and HRD parameters were derived from 24-hour electrocardiogram recordings. Each parameter obtained was then used as the outcome variable in multivariable mixed linear regression models in order to evaluate the association with TPM₁₀. Potential modifying effects were assessed using interaction terms.

RESULTS

No association between long-term exposure to TPM₁₀ and HRV/HRD was observed in the entire study population. However, HRD changes were found in subjects without cardiovascular morbidity and both HRD and HRV changes in non-obese subjects without cardiovascular morbidity. Subjects without cardiovascular morbidity with homozygous GSTM1 gene deletion appeared to be more susceptible to the effects of TPM₁₀.

CONCLUSION

This study suggests that long-term exposure to TPM₁₀ triggers adverse changes in the regulation of the cardiovascular system. These adverse effects were more visible in the subjects without cardiovascular disease, in whom the overall relationship between TPM₁₀ and HRV/HRD could not be masked by underlying morbidities and the potential counteracting effects of related drug treatments.

Inhibitory effects of protopanaxatriol type ginsenoside fraction (Rgx365) on particulate matter-induced pulmonary injury

Inhalation of fine particulate matter (PM_2.5) is associated with elevated pulmonary injury attributed to the loss of vascular barrier integrity. Black ginseng (BG), steamed 9 times and dried ginseng, and its major protopanaxatriol type ginsenosides (ginsenoside Rg4, Rg6, Rh4, Rh1, and Rg2) exhibited various biological activities including anti-septic, anti-diabetic, wound healing, immune-stimulatory, and anti-antioxidant activity. The aim of this study was to investigate the beneficial effects of Rgx365 (a protopanaxatriol type rare ginsenosides fraction) on PM-induced lung endothelial cell (EC) barrier disruption and pulmonary inflammation. Permeability, leukocyte migration, activation of proinflammatory proteins, generation of reactive oxygen species (ROS), and histology were examined in PM_2.5-treated EC and mice. Rgx365 significantly scavenged PM_2.5-induced ROS, inhibited ROS-induced activation of p38 mitogen-activated protein kinase (MAPK), activated Akt in purified pulmonary EC, which helped maintain endothelial integrity. Further, Rgx365 reduced vascular protein leakage, leukocyte infiltration, and proinflammatory cytokine release in bronchoalveolar lavage fluids in PM-induced mouse lung tissues. Data suggested that Rgx365 might exhibit protective effects in PM-induced inflammatory lung injury and vascular hyperpermeability.

Child's buccal cell mitochondrial DNA content modifies the association between heart rate variability and recent air pollution exposure at school

BACKGROUND

Studies investigating short-term exposure to ambient air pollution and heart rate variability (HRV) suggest that particulate matter (PM) exposure is associated with reductions in measures of HRV. Mitochondria are sensitive to PM exposure and may represent a biologically relevant underlying mechanism. However, evidence in children is lacking.

OBJECTIVES

Here we examine whether PM has an influence on children's HRV and evaluate whether mitochondrial DNA content (mtDNAc) reflects individual susceptibility.

METHODS

Within a panel study in primary school children (aged 9-12 years), we measured HRV in a subset of 60 children on three different days during school-time using four indicators: normal-to-normal intervals (SDNN), square root of mean squared difference of normal-to-normal intervals (rMSSD), high frequency (HF), and low frequency (LF). This resulted in a total number of 150 visits (median number of visits per child: 2.5/child). MtDNAc was measured using qPCR in buccal cells. We measured recent PM exposure at the school. Residential 24-hour mean exposure to PM was modelled with a high resolution spatial temporal model. Mixed-effects models were used to estimate the association between HRV and recent PM exposure and potential effect-modification by mtDNAc.

RESULTS

Children were on average [SD] 9.9 [1.2] years and comprised 39 girls. Median [25th-75th] recent outdoor PM_2.5 and PM₁₀ exposure at school was 6.20 [2.8-12.8] μg/m³ and 29.3 [24.7-42.0] μg/m³, respectively. In children with low mtDNAc (25th percentile), we observed for each 10 μg/m³ increment in recent PM_2.5 exposure a lowering in the LF parameter with 9.76% (95% CI: -16.9 to -1.99%, p = 0.02; p_int = 0.007). Children with high mtDNAc did not show this association. For PM₁₀ exposure, we observed an inverse association with three HRV indicators in children with low mtDNAc: -2.24% (95% CI: -4.27 to -0.16%; p = 0.04; p_int = 0.02) for SDNN, -5.67% (95% CI: -10.5 to -0.59%; p = 0.03; p_int = 0.04) for HF and -6.64% (95% CI: -10.7 to -2.38%; p = 0.003; p_int = 0.005) for LF.

CONCLUSIONS

HRV is inversely associated with recent PM air pollution, especially in children with low mtDNAc. Our data revealed that mtDNAc determines susceptibility to adverse autonomic effects of recent PM exposure in children.

Cardiovascular benefits of short-term indoor air filtration intervention in elderly living in Beijing: An extended analysis of BIAPSY study

BACKGROUND

Adverse cardiovascular effects associated with air pollution exposure have been widely demonstrated. However, inconsistent cardiovascular responses were observed from reducing indoor air pollution exposure. We aimed to assess whether short-term air filtration intervention could benefit cardiovascular health in elderly living in high pollution area.

METHODS

A randomized crossover intervention study of short-term indoor air filtration intervention on cardiovascular health was conducted among 35 non-smoking elderly participants living in Beijing in the winter of 2013, as part of Beijing Indoor Air Purifier StudY (BIAPSY). Portable air filtration units were randomly allocated to active filtration for 2 weeks and sham filtration for 2 weeks in the households. Twelve-hour daytime ambulatory heart rate variability (HRV) and blood pressure (ABP) were measured during active and sham filtration. Concurrently, real-time indoor and outdoor particulate matter with diameter less than 2.5 µm (PM_2.5) and indoor black carbon (BC) concentrations were measured. We applied generalized additive mixed models to evaluate the associations of 1- to 10-h moving average (MA) exposures of indoor PM_2.5 and BC with HRV and ABP indices, and to explore whether these associations could be modified by air filtration.

RESULTS

We observed decreases of 34.8% in indoor PM_2.5 and 35.3% in indoor BC concentrations during active filtration. Indoor PM_2.5 and BC exposures were significantly associated with reduced HRV and increased ABP indices, and greater changes were observed during sham filtration. In specific, each 10 μg/m³ increase in indoor PM_2.5 at MA8-h was associated with a significant reduction of 1.34% (95% CI: -2.42, -0.26) in SDNN during sham filtration, compared with a non-significant reduction of 0.81% (95% CI: -6.00, 4.68) during active filtration (P_inter< 0.001). Each 1 μg/m³ increase in indoor BC at MA8-h was associated with a significant increase of 2.41% (95% CI: 0.38, 4.47) in SBP during sham filtration, compared with a non-significant increase of -1.09% (95% CI: -4.06, 1.96) during active filtration (P_inter = 0.135). Nonlinear inverse exposure-response relationships of indoor air pollution exposures with predicted HRV and ABP indices also confirmed some cardiovascular benefits of short-term air filtration intervention.

CONCLUSIONS

Our results suggested that short-term indoor air filtration intervention can be of some cardiovascular benefits in elderly living with high pollution episodes.

Gene-Metabolite Interaction in the One Carbon Metabolism Pathway: Predictors of Colorectal Cancer in Multi-Ethnic Families

For personalized healthcare, the purpose of this study was to examine the key genes and metabolites in the one-carbon metabolism (OCM) pathway and their interactions as predictors of colorectal cancer (CRC) in multi-ethnic families. In this proof-of-concept study, we included a total of 30 participants, 15 CRC cases and 15 matched family/friends representing major ethnic groups in southern California. Analytics based on supervised machine learning were applied, with the target variable being specified as cancer, including the ensemble method and generalized regression (GR) prediction. Elastic Net with Akaike's Information Criterion with correction (AICc) and Leave-One-Out cross validation GR methods were used to validate the results for enhanced optimality, prediction, and reproducibility. The results revealed that despite some family members sharing genetic heritage, the CRC group had greater combined gene polymorphism-mutations than the family controls (p < 0.1) for five genes including MTHFR C677T, MTHFR A1298C, MTR A2756G, MTRR A66G, and DHFR 19bp. Blood metabolites including homocysteine (7 µmol/L), methyl-folate (40 nmol/L) with total gene mutations (≥4); age (51 years) and vegetable intake (2 cups), and interactions of gene mutations and methylmalonic acid (MMA) (400 nmol/L) were significant predictors (all p < 0.0001) using the AICc. The results were validated by a 3% misclassification rate, AICc of 26, and >99% area under the receiver operating characteristic curve. These results point to the important roles of blood metabolites as potential markers in the prevention of CRC. Future intervention studies can be designed to target the ways to mitigate the enzyme-metabolite deficiencies in the OCM pathway to prevent cancer.

Meta-Analysis of NOS3 G894T Polymorphisms with Air Pollution on the Risk of Ischemic Heart Disease Worldwide

The purpose of this updated meta-analysis was to investigate the effect of nitric oxide synthase-3 (NOS3) G894T polymorphisms, air pollution and their interaction on ischemic heart disease (IHD) risk across populations worldwide. Recursive partition trees, nonlinear association curve fit and geographic information system maps were incorporated to verify results of conventional pooled analyses for sources of heterogeneity. Results from 61 studies (16,219 cases, 12,222 controls) revealed a significant increased relative risk (RR) of IHD associated with NOS3 894 polymorphisms TT (RR = 1.44) and GT (RR = 1.37). Subgroup analysis revealed that the TT polymorphism genotype had significantly increased risk of IHD in Caucasian, East Asian, South Asian, and Middle Eastern populations (all p < 0.05). It is important to point out that many countries demonstrated an average risk of greater than two, which identifies the NOS3 894 TT polymorphism as a potential causal factor and biological marker of IHD, based on criteria for strong evidence used in international consensus panels. These 10 countries include Ukraine, the United Kingdom, Brazil, Chile, Japan, South Korea, India, Iran, Egypt and Morocco. For these countries with elevated risk (RR > 2) from the NOS3 894 TT polymorphism, meta-predictive analysis demonstrated an increasing trend in air pollution association with increased NOS3 894 polymorphisms. Further studies are needed to explore the complexity of the associations among NOS3 gene polymorphisms per population stratifications within countries, detailed air pollution data for added specificity for geographic location across time, and disease risk.

Personalized Nutrition-Genes, Diet, and Related Interactive Parameters as Predictors of Cancer in Multiethnic Colorectal Cancer Families

To personalize nutrition, the purpose of this study was to examine five key genes in the folate metabolism pathway, and dietary parameters and related interactive parameters as predictors of colorectal cancer (CRC) by measuring the healthy eating index (HEI) in multiethnic families. The five genes included methylenetetrahydrofolate reductase (MTHFR) 677 and 1298, methionine synthase (MTR) 2756, methionine synthase reductase (MTRR 66), and dihydrofolate reductase (DHFR) 19bp, and they were used to compute a total gene mutation score. We included 53 families, 53 CRC patients and 53 paired family friend members of diverse population groups in Southern California. We measured multidimensional data using the ensemble bootstrap forest method to identify variables of importance within domains of genetic, demographic, and dietary parameters to achieve dimension reduction. We then constructed predictive generalized regression (GR) modeling with a supervised machine learning validation procedure with the target variable (cancer status) being specified to validate the results to allow enhanced prediction and reproducibility. The results showed that the CRC group had increased total gene mutation scores compared to the family members (p < 0.05). Using the Akaike’s information criterion and Leave-One-Out cross validation GR methods, the HEI was interactive with thiamine (vitamin B1), which is a new finding for the literature. The natural food sources for thiamine include whole grains, legumes, and some meats and fish which HEI scoring included as part of healthy portions (versus limiting portions on salt, saturated fat and empty calories). Additional predictors included age, as well as gender and the interaction of MTHFR 677 with overweight status (measured by body mass index) in predicting CRC, with the cancer group having more men and overweight cases. The HEI score was significant when split at the median score of 77 into greater or less scores, confirmed through the machine-learning recursive tree method and predictive modeling, although an HEI score of greater than 80 is the US national standard set value for a good diet. The HEI and healthy eating are modifiable factors for healthy living in relation to dietary parameters and cancer prevention, and they can be used for personalized nutrition in the precision-based healthcare era.

Ambient Air Pollution and Clinical Implications for Susceptible Populations

Air pollution is associated with a diversity of health effects, and evidence for a causal relationship with specific diseases exists. Exposure to air pollution is ubiquitous and typically beyond the control of the individual; the resulting health burden for the population can be high. Disproportionate effects are seen in individuals who have increased susceptibility to air pollution owing to individual- or community-level characteristics. As studies grow increasingly sophisticated, the understanding of who comprises the susceptible population continuously expands. Characteristics of susceptibility include genetic predisposition; socioeconomic factors; life stage; the presence of preexisting diseases, such as asthma, chronic obstructive pulmonary disease, cystic fibrosis; and the unique population of lung transplant recipients. This review explores how select populations, namely individuals with preexisting pulmonary disease and those living in communities of low socioeconomic status, have an increased susceptibility to the health effects of ambient air pollution. Genetic susceptibility, though a fundamental determinant of risk, is beyond the scope of this review and is not discussed. Strategies designed to mitigate air pollution-related health effects are discussed using a framework that addresses pollution exposure at multiple levels-government, state, community, and the individual. Emission reduction strategies remain the basis for public health protection; however, ancillary harm reduction measures are explored that can be adopted by susceptible communities and individuals.

Effects of Diesel Exhaust on Cardiovascular Function and Oxidative Stress

SIGNIFICANCE

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

CRITICAL ISSUES

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

FUTURE DIRECTIONS

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

Gene Environment Interactions and Predictors of Colorectal Cancer in Family-Based, Multi-Ethnic Groups

For the personalization of polygenic/omics-based health care, the purpose of this study was to examine the gene-environment interactions and predictors of colorectal cancer (CRC) by including five key genes in the one-carbon metabolism pathways. In this proof-of-concept study, we included a total of 54 families and 108 participants, 54 CRC cases and 54 matched family friends representing four major racial ethnic groups in southern California (White, Asian, Hispanics, and Black). We used three phases of data analytics, including exploratory, family-based analyses adjusting for the dependence within the family for sharing genetic heritage, the ensemble method, and generalized regression models for predictive modeling with a machine learning validation procedure to validate the results for enhanced prediction and reproducibility. The results revealed that despite the family members sharing genetic heritage, the CRC group had greater combined gene polymorphism rates than the family controls (p < 0.05), on MTHFR C677T, MTR A2756G, MTRR A66G, and DHFR 19 bp except MTHFR A1298C. Four racial groups presented different polymorphism rates for four genes (all p < 0.05) except MTHFR A1298C. Following the ensemble method, the most influential factors were identified, and the best predictive models were generated by using the generalized regression models, with Akaike's information criterion and leave-one-out cross validation methods. Body mass index (BMI) and gender were consistent predictors of CRC for both models when individual genes versus total polymorphism counts were used, and alcohol use was interactive with BMI status. Body mass index status was also interactive with both gender and MTHFR C677T gene polymorphism, and the exposure to environmental pollutants was an additional predictor. These results point to the important roles of environmental and modifiable factors in relation to gene-environment interactions in the prevention of CRC.

Meta-Prediction of MTHFR Gene Polymorphisms and Air Pollution on the Risk of Hypertensive Disorders in Pregnancy Worldwide

Hypertensive disorders in pregnancy (HDP) are devastating health hazards for both women and children. Both methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and air pollution can affect health status and result in increased risk of HDP for women. The major objective of this study was to investigate the effect of MTHFR polymorphisms, air pollution, and their interaction on the risk of HDP by using meta-predictive analytics. We searched various databases comprehensively to access all available studies conducted for various ethnic populations from countries worldwide, from 1997 to 2017. Seventy-one studies with 8064 cases and 13,232 controls for MTHFR C677T and 11 studies with 1425 cases and 1859 controls for MTHFR A1298C were included. MTHFR C677T homozygous TT (risk ratio (RR) = 1.28, p < 0.0001) and CT plus TT (RR = 1.07, p = 0.0002) were the risk genotypes, while wild-type CC played a protective role (RR = 0.94, p = 0.0017) for HDP. The meta-predictive analysis found that the percentage of MTHFR C677T TT plus CT (p = 0.044) and CT (p = 0.043) genotypes in the HDP case group were significantly increased with elevated levels of air pollution worldwide. Additionally, in countries with higher air pollution levels, the pregnant women with wild-type CC MTHFR 677 had a protection effect against HDP (p = 0.014), whereas, the homozygous TT of MTHFR C677T polymorphism was a risk genotype for developing HDP. Air pollution level is an environmental factor interacting with increased MTHFR C677T polymorphisms, impacting the susceptibility of HDP for women.

Epigenetic modifications of gene expression by lifestyle and environment

Epigenetics oftenly described as the heritable changes in gene expression independent of changes in DNA sequence. Various environmental factors such as nutrition-dietary components, lifestyle, exercise, physical activity, toxins, and other contributing factors remodel the genome either in a constructive or detrimental way. Since epigenetic changes are reversible and nutrition is one of the many epigenetic regulators that modify gene expression without changing the DNA sequence, dietary nutrients and bioactive food components contribute to epigenetic phenomena either by directly suppressing DNA methylation or histone catalyzing enzymes or by changing the availability of substrates required for enzymatic reactions. Diets that contain catechol-dominant polyphenols are reported to suppress enzyme activity and activate epigenetically silenced genes. Furthermore, several dietary nutrients play a crucial role in one-carbon metabolism including folate, cobalamin, riboflavin, pyridoxine, and methionine by directly affecting S-adenosyl-L-methionine. Soy polyphenols block DNA methyltransferases and histone deacetylases to reverse aberrant CpG island methylation. Organosulfur rich compounds such as the sulforaphane found in broccoli appear to normalize DNA methylation and activate miR-140 expression, which represses SOX9 and ALDH1 and decreases tumor growth. The purpose of this short communication is to overview the epigenetic regulatory mechanisms of diet and other environmental factors. We discuss the epigenetic contributions of dietary components with a particular focus on nutritional polyphenols and flavonoids as epigenetic mediators that modify epigenetic tags and control gene expression. These mechanisms provide new insights to better understand the influence of dietary nutrients on epigenetic modifications and gene expression.

Maternal Exposure to Nitrogen Dioxide, Intake of Methyl Nutrients, and Congenital Heart Defects in Offspring

Nutrients that regulate methylation processes may modify susceptibility to the effects of air pollutants. Data from the National Birth Defects Prevention Study (United States, 1997-2006) were used to estimate associations between maternal exposure to nitrogen dioxide (NO2), dietary intake of methyl nutrients, and the odds of congenital heart defects in offspring. NO2 concentrations, a marker of traffic-related air pollution, averaged across postconception weeks 2-8, were assigned to 6,160 nondiabetic mothers of cases and controls using inverse distance-squared weighting of air monitors within 50 km of maternal residences. Intakes of choline, folate, methionine, and vitamins B6 and B12 were assessed using a food frequency questionnaire. Hierarchical regression models, which accounted for similarities across defects, were constructed, and relative excess risks due to interaction were calculated. Relative to women with the lowest NO2 exposure and high methionine intake, women with the highest NO2 exposure and lowest methionine intake had the greatest odds of offspring with a perimembranous ventricular septal defect (odds ratio = 3.23, 95% confidence interval: 1.74, 6.01; relative excess risk due to interaction = 2.15, 95% confidence interval: 0.39, 3.92). Considerable departure from additivity was not observed for other defects. These results provide modest evidence of interaction between nutrition and NO2 exposure during pregnancy.

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.

B-vitamin Supplementation Mitigates Effects of Fine Particles on Cardiac Autonomic Dysfunction and Inflammation: A Pilot Human Intervention Trial

Ambient fine particle (PM_2.5) pollution triggers acute cardiovascular events. Individual-level preventions are proposed to complement regulation in reducing the global burden of PM_2.5–induced cardiovascular diseases. We determine whether B vitamin supplementation mitigates PM_2.5 effects on cardiac autonomic dysfunction and inflammation in a single-blind placebo-controlled crossover pilot trial. Ten healthy adults received two-hour controlled-exposure-experiment to sham under placebo, PM_2.5 (250 μg/m³) under placebo, and PM_2.5 (250 μg/m³) under B-vitamin supplementation (2.5 mg/d folic acid, 50 mg/d vitamin B₆, and 1 mg/d vitamin B₁₂), respectively. At pre-, post-, 24 h-post-exposure, we measured resting heart rate (HR) and heart rate variability (HRV) with electrocardiogram, and white blood cell (WBC) counts with hematology analyzer. Compared to sham, PM_2.5 exposure increased HR (3.8 bpm, 95% CI: 0.3, 7.4; P = 0.04), total WBC count (11.5%, 95% CI: 0.3%, 24.0%; P = 0.04), lymphocyte count (12.9%, 95% CI: 4.4%, 22.1%; P = 0.005), and reduced low-frequency power (57.5%, 95% CI: 2.5%, 81.5%; P = 0.04). B-vitamin supplementation attenuated PM_2.5 effect on HR by 150% (P = 0.003), low-frequency power by 90% (P = 0.01), total WBC count by 139% (P = 0.006), and lymphocyte count by 106% (P = 0.02). In healthy adults, two-hour PM_2.5 exposure substantially increases HR, reduces HRV, and increases WBC. These effects are reduced by B vitamin supplementation.

Cardiovascular pharmacogenetics: a promise for genomically-guided therapy and personalized medicine

Cardiovascular disease (CVD) is the leading cause of death worldwide. The basic causes of CVD are not fully understood yet. Substantial evidence suggests that genetic predisposition plays a vital role in the physiopathology of this complex disease. Hence, identification of genetic contributors to CVD will likely add diagnostic accuracy and better prediction of an individual's risk. With high-throughput genetics and genomics technology and newer genome-wide study approaches, a number of genetic variations across the human genome were uncovered. Evidence suggests that genetic defects could influence CVD development and inter-individual responses to widely used cardiovascular drugs like clopidogrel, aspirin, warfarin, and statins, and therefore, they may be integrated into clinical practice. If clinically validated, better understanding of these genetic variations may provide new opportunities for personalized diagnostic, pharmacogenetic-based drug selection and best treatment in personalized medicine. However, numerous gaps remain unsolved due to the lack of underlying pathological mechanisms for how genetic predisposition could contribute to CVD. This review provides an overview of the extraordinary scientific progress in our understanding of genetic and genomic basis of CVD as well as the development of relevant genetic biomarkers for this disease. Some of the actual limitations to the promise of these markers and their translation for the benefit of patients will be discussed.

Cardiovascular Benefits of Wearing Particulate-Filtering Respirators: A Randomized Crossover Trial

BACKGROUND

Practical approaches to protect individuals from ambient particulate matter (PM) are urgently needed in developing countries. Evidence on the health benefits of wearing particulate-filtering respirators is limited.

OBJECTIVES

We evaluated the short-term cardiovascular health effects of wearing respirators in China.

METHODS

A randomized crossover trial was performed in 24 healthy young adults in Shanghai, China in 2014. The subjects were randomized into two groups and wore particulate-filtering respirators for 48 hr alternating with a 3-week washout interval. Heart rate variability (HRV) and ambulatory blood pressure (BP) were continuously monitored during the 2nd 24 hr in each intervention. Circulating biomarkers were measured at the end of each intervention. Linear mixed-effect models were applied to evaluate the effects of wearing respirators on health outcomes.

RESULTS

During the intervention periods, the mean daily average concentration of PM with an aerodynamic diameter < 2.5 μm (PM2.5) was 74.2 μg/m3. Compared with the absence of respirators, wearing respirators was associated with a decrease of 2.7 mmHg [95% confidence interval (CI): 0.1, 5.2 mmHg] in systolic BP and increases of HRV parameters, including 12.5% (95% CI: 3.8%, 21.2%) in high frequency (HF) power, 10.9% (95% CI: 1.8%, 20.0%) in the root mean square of the successive differences, and 22.1% (95% CI: 3.6%, 40.7%) in the percentage of normal RR intervals with duration > 50 msec different from the previous normal RR interval (pNN50). The presence of respirators was also associated with a decrease of 7.8% (95% CI: 3.5%, 12.1%) in the ratio of low frequency (LF)/HF power.

CONCLUSIONS

Short-term wearing of particulate-filtering respirators may produce cardiovascular benefits by improving autonomic nervous function and reducing BP. Citation: Shi J, Lin Z, Chen R, Wang C, Yang C, Cai J, Lin J, Xu X, Ross JA, Zhao Z, Kan H. 2017. Cardiovascular benefits of wearing particulate-filtering respirators: a randomized crossover trial. Environ Health Perspect 125:175-180; http://dx.doi.org/10.1289/EHP73.

The role of micronutrients in the response to ambient air pollutants: Potential mechanisms and suggestions for research design

People living in regions of low socioeconomic status are thought to be prone to higher exposures to environmental pollutants, poor nutrition, and numerous preventable diseases and infections. Poverty correlates with pollution and malnutrition; however, limited studies examined their interrelationship. The well-studied, deleterious health effects attributed to environmental pollutants and poor nutrition may act in combination with produce more severe adverse health outcomes than any one factor alone. Deficiencies in specific nutrients render the body more susceptible to injury which may influence the pathways that serve as the mechanistic responses to ambient air pollutants. This review (1) explores specific micronutrients that are of global concern, (2) explains how these nutrients may impact the body's response to ambient air pollution, and (3) provides guidance on designing animal models of nutritional deficiency. It is likely that those individuals who reside in regions of high ambient air pollution are similarly malnourished. Therefore, it is important that research identifies specific nutrients of concern and their impact in identified regions of high ambient air pollution.

Does total antioxidant capacity modify adverse cardiac responses associated with ambient ultrafine, accumulation mode, and fine particles in patients undergoing cardiac rehabilitation?

BACKGROUND

Previous studies suggest that pathways reducing oxidative stress may have a protective effect against adverse cardiac responses associated with ambient PM. However, few studies have directly assessed total antioxidant capacity (TAC) as a potential effect modifier of cardiac responses to increased ambient PM.

OBJECTIVES

We examined if TAC modifies the association between ambient PM and markers of heart rate variability (HRV), repolarization, systemic inflammation, and systolic blood pressure (SBP) in post-infarction patients.

METHODS

We recruited 76 patients with a recent coronary event (myocardial infarction or unstable angina) who participated in a cardiac rehabilitation program from June 2006 to November 2009 in Rochester, New York. Ambient fine particle (PM2.5,≤2.5µm in aerodynamic diameter), accumulation mode particle (AMP, 100-500nm) and ultrafine particle (UFP, 10-100nm) concentrations were measured continuously by fixed-site monitors. Markers of HRV and repolarization were measured by continuous Holter electrocardiogram (ECG) recordings before and during exercise sessions of the rehabilitation program. Blood pressure was measured and venous blood samples were collected before exercise to measure TAC and inflammation markers. We applied linear mixed models to assess changes in markers of HRV, repolarization, systemic inflammation, and SBP associated with increased PM concentrations in the low, medium and high TAC tertile groups, after adjusting for covariates including temperature, calendar time since the beginning of the study, visit number, month of year, and hour of day.

RESULTS

Based on subject-visits with available TAC, we observed increases in SBP, C-reactive protein, and fibrinogen, and decreases in rMSSD (square root of the mean of the sum of the squared differences between adjacent normal to normal intervals) and SDNN (standard deviation of normal to normal beat intervals) associated with increased PM2.5, AMP and UFP in the previous 6-120h (e.g. change in SBP associated with each interquartile range (IQR) increase in PM2.5 lagged 0-5h was 1.27mmHg [95%CI: 0.09, 2.46mmHg]). However, we did not observe a consistent pattern of effect measure modification by TAC for any combination of pollutant and outcome (e.g. changes in SBP associated with each IQR increase in PM2.5 lagged 0-5h for the low, medium and high TAC tertile groups were 1.93mmHg [95%CI: 0.23, 3.63 mmHg], -0.31 mmHg [95%CI: -2.62, 2.01 mmHg], and 1.29mmHg [95%CI: -0.64, 3.21 mmHg], respectively. P for interaction=0.28).

CONCLUSIONS

In a post-infarction population, total antioxidant capacity does not appear to modify the association between biomarkers of heart rate variability, repolarization, systemic inflammation, and systolic blood pressure and ambient PM concentrations in the previous 6-120h.

Associations of air pollution exposure with blood pressure and heart rate variability are modified by oxidative stress genes: A repeated-measures panel among elderly urban residents

BACKGROUND

Oxidative stress has been suggested as a major cause of elevated blood pressure (BP) and reduced heart rate variability (HRV) due to air pollution. We hypothesized that the associations of air pollution exposure with BP and HRV are modified by oxidative stress gene polymorphisms.

METHODS

Between 2008 and 2010, we conducted up to 5 surveys of 547 elderly participants, measured their BP and HRV, and genotyped 47 single nucleotide polymorphisms (SNPs) in 18 oxidative stress genes. Linear mixed models were constructed to evaluate the associations of particulate matter ≤10 μm, nitrogen dioxide, and sulfur dioxide with BP and HRV, as well as the modifications of these associations by the genotyped SNPs.

RESULTS

Single-SNP analyses revealed interactions between air pollution and 15 SNPs (for BP) and 33 SNPs (for HRV) (all, P for interaction < 0.05). When we generated genetic risk scores for BP and HRV, using the SNPs with interactions in the single-SNP models, we found that associations of air pollution exposure with BP and HRV were modified by the genetic risk scores (P for interaction < 0.05).

CONCLUSIONS

These results strongly suggest that the associations of air pollution with BP and HRV are mediated by oxidative stress pathways.

Amelioration of particulate matter-induced oxidative damage by vitamin c and quercetin in human bronchial epithelial cells

Exposure to fine particulate matter (PM2.5) has a close association with respiratory damage. Vitamin c and quercetin have been documented to possess antioxidant and anti-inflammation properties. However, their potential protective effects against PM2.5-induced respiratory damage have not been evaluated yet. Hence, the study was aimed to investigate their protective effects and delineate the possible mechanisms. The results indicated that PM2.5 depleted the cell viability of 16HBE cells, elevated reactive oxygen species (ROS) generation, and inhibited mitochondrial genes expressions, including fusion proteins Mfn1 and OPA1, along with biogenesis markers SIRT1 and p53R2. Additionally, the damage of mitochondrial morphology was observed upon PM2.5 exposure using both JC-1 and MitoTracker Red staining. Expressions of mitochondrial respiratory chain genes including NDUFS2 and UQCRI1 were also attenuated by PM2.5 exposure. Furthermore, PM2.5 promoted the mRNA levels of NADPH oxidase and inflammation cytokines. However, the addition of vitamin c or quercetin strikingly antagonized the PM2.5-induced toxic effects. Collectively, these findings suggest that vitamin c and quercetin have repressive roles in respiratory oxidative damage incurred by PM2.5, which provide the theoretical basis about intervention and control of food nutrients on PM2.5-induced human adverse health.

Nutritional Solutions to Reduce Risks of Negative Health Impacts of Air Pollution

Air pollution worldwide has been associated with cardiovascular and respiratory morbidity and mortality, particularly in urban settings with elevated concentrations of primary pollutants. Air pollution is a very complex mixture of primary and secondary gases and particles, and its potential to cause harm can depend on multiple factors—including physical and chemical characteristics of pollutants, which varies with fine-scale location (e.g., by proximity to local emission sources)—as well as local meteorology, topography, and population susceptibility. It has been hypothesized that the intake of anti-oxidant and anti-inflammatory nutrients may ameliorate various respiratory and cardiovascular effects of air pollution through reductions in oxidative stress and inflammation. To date, several studies have suggested that some harmful effects of air pollution may be modified by intake of essential micronutrients (such as B vitamins, and vitamins C, D, and E) and long-chain polyunsaturated fatty acids. Here, we review the existing literature related to the potential for nutrition to modify the health impacts of air pollution, and offer a framework for examining these interactions.

Framingham risk score modifies the effect of PM10 on heart rate variability

Health conditions may greatly modify the association between particulate matter (PM) and heart rate variability (HRV), but whether the modification of PM effect by coronary artery disease (CAD) risk status depends on the PM levels remains unknown. We investigated the associations between personal exposures to PM with aerodynamic diameter of ≤10μm (PM10) and ≤2.5μm (PM2.5) and concurrent HRV, and whether the effect of PM on HRV was modified by Framingham risk score (FRS) in healthy subjects with different PM exposure levels. Personal exposures to PM10 and PM2.5 were measured for 24h in 152 volunteers of community residents who were free of cardiovascular disease in two cities (Zhuhai and Wuhan) that differ in air quality. Simultaneously, 24h HRV indices were obtained from 3-channel Holter monitor. FRS was calculated based on age, sex, lipid profiles, blood pressure, diabetes, and smoking status. Linear regression models were constructed after adjusting for potential confounders. We found significant decrease in total power (TP) and low power (LF) with increased PM10 concentrations (P for trend<0.05) in the high PM levels city (Wuhan) and total population, but not in the low PM levels city (Zhuhai). We also observed significant modification of FRS on PM10 effect in Wuhan. Interestingly, elevated PM10 was associated in a greater decreased HRV in the low FRS subgroup, but not in the high FRS subgroup. However, we did not find any significant main effects of PM2.5 or PM2.5-FRS interactions on HRV in city-specified or city-combined analyses. Overall, the findings indicate that individual coronary risk profiles may modulate the association between particulate air pollution and HRV in high PM exposure levels.

Identifying Common Genetic Risk Factors of Diabetic Neuropathies

Type 2 diabetes mellitus (T2DM) is a global public health problem of epidemic proportions, with 60-70% of affected individuals suffering from associated neurovascular complications that act on multiple organ systems. The most common and clinically significant neuropathies of T2DM include uremic neuropathy, peripheral neuropathy, and cardiac autonomic neuropathy. These conditions seriously impact an individual's quality of life and significantly increase the risk of morbidity and mortality. Although advances in gene sequencing technologies have identified several genetic variants that may regulate the development and progression of T2DM, little is known about whether or not the variants are involved in disease progression and how these genetic variants are associated with diabetic neuropathy specifically. Significant missing heritability data and complex disease etiologies remain to be explained. This article is the first to provide a review of the genetic risk variants implicated in the diabetic neuropathies and to highlight potential commonalities. We thereby aim to contribute to the creation of a genetic-metabolic model that will help to elucidate the cause of diabetic neuropathies, evaluate a patient's risk profile, and ultimately facilitate preventative and targeted treatment for the individual.

Toxicology of ambient particulate matter

It is becoming increasingly clear that inhalation exposure to particulate matter (PM) can lead to or exacerbate various diseases, which are not limited to the lung but extend to the cardiovascular system and possibly other organs and tissues. Epidemiological studies have provided strong evidence for associations with chronic obstructive pulmonary disease (COPD), asthma, bronchitis and cardiovascular disease, while the evidence for a link with lung cancer is less strong. Novel research has provided first hints that exposure to PM might lead to diabetes and central nervous system (CNS) pathology. In the current review, an overview is presented of the toxicological basis for adverse health effects that have been linked to PM inhalation. Oxidative stress and inflammation are discussed as central processes driving adverse effects; in addition, profibrotic and allergic processes are implicated in PM-related diseases. Effects of PM on key cell types considered as regulators of inflammatory, fibrotic and allergic mechanisms are described.

Cardiac autonomic dysfunction: particulate air pollution effects are modulated by epigenetic immunoregulation of Toll-like receptor 2 and dietary flavonoid intake

Background

Short‐term fine particles (PM_2.5) exposure is associated with reduced heart rate variability, a strong predictor of cardiac mortality among older people. Identifying modifiable factors that confer susceptibility is essential for intervention. We evaluated whether Toll‐like receptor 2 (TLR2) methylation, a reversible immune‐epigenetic process, and its dietary modulation by flavonoids and methyl nutrients, modify susceptibility to heart rate variability effects following PM_2.5 exposure.

Methods and Results

We measured heart rate variability and PM_2.5 repeatedly over 11 years (1275 total observations) among 573 elderly men from the Normative Aging Study. Blood TLR2 methylation was analyzed using pyrosequencing. Daily flavonoid and methyl nutrients intakes were assessed through the Food Frequency Questionnaire (FFQ). Every 10 μg/m³ increase in 48‐hour PM_2.5 moving average was associated with 7.74% (95% CI: −1.21% to 15.90%; P=0.09), 7.46% (95% CI: 0.99% to 13.50%; P=0.02), 14.18% (95% CI: 1.14% to 25.49%; P=0.03), and 12.94% (95% CI: −2.36% to 25.96%; P=0.09) reductions in root mean square of successive differences, standard deviation of normal‐to‐normal intervals, low‐frequency power, and high‐frequency power, respectively. Higher TLR2 methylation exacerbated the root mean square of successive differences, standard deviation of normal‐to‐normal intervals, low‐frequency, and high‐frequency reductions associated with heightened PM_2.5 (P_interaction=0.006, 0.03, 0.05, 0.04, respectively). Every interquartile‐range increase in flavonoid intake was associated with 5.09% reduction in mean TLR2 methylation (95% CI: 0.12% to 10.06%; P=0.05) and counteracted the effects of PM_2.5 on low frequency (P_interaction=0.05). No significant effect of methyl nutrients on TLR2 methylation was observed.

Conclusions

Higher TLR2 methylation may confer susceptibility to adverse cardiac autonomic effects of PM_2.5 exposure in older individuals. Higher flavonoid intake may attenuate these effects, possibly by decreasing TLR2 methylation.

Activation of TRPV1 attenuates high salt-induced cardiac hypertrophy through improvement of mitochondrial function

BACKGROUND AND PURPOSE

High-salt diet induces cardiac remodelling and leads to heart failure, which is closely related to cardiac mitochondrial dysfunction. Transient receptor potential (TRP) channels are implicated in the pathogenesis of cardiac dysfunction. We investigated whether activation of TRP vanilloid (subtype 1) (TRPV1) channels by dietary capsaicin can, by ameliorating cardiac mitochondrial dysfunction, prevent high-salt diet-induced cardiac hypertrophy.

EXPERIMENTAL APPROACH

Male wild-type (WT) and TRPV1(-/-) mice were fed a normal or high-salt diet with or without capsaicin for 6 months. Their cardiac parameters and endurance capacity were assessed. Mitochondrial respiration and oxygen consumption were measured using high-resolution respirometry. The expression levels of TRPV1, sirtuin 3 and NDUFA9 were detected in cardiac cells and tissues.

KEY RESULTS

Chronic high-salt diet caused cardiac hypertrophy and reduced physical activity in mice; both effects were ameliorated by capsaicin intake in WT but not in TRPV1(-/-) mice. TRPV1 knockout or high-salt diet significantly jeopardized the proficiency of mitochondrial Complex I oxidative phosphorylation (OXPHOS) and reduced Complex I enzyme activity. Chronic dietary capsaicin increased cardiac mitochondrial sirtuin 3 expression, the proficiency of Complex I OXPHOS, ATP production and Complex I enzyme activity in a TRPV1-dependent manner.

CONCLUSIONS AND IMPLICATIONS

TRPV1 activation by dietary capsaicin can antagonize high-salt diet-mediated cardiac lesions by ameliorating its deleterious effect on the proficiency of Complex I OXPHOS. TRPV1-mediated amendment of mitochondrial dysfunction may represent a novel target for management of early cardiac dysfunction.

Cardiorespiratory treatments as modifiers of the relationship between particulate matter and health: a case-only analysis on hospitalized patients in Italy

BACKGROUND

A few panel and toxicological studies suggest that health effects of particulate matter (PM) might be modified by medication intake, but whether this modification is confirmed in the general population or for more serious outcomes is still unknown.

OBJECTIVES

We carried out a population-based pilot study in order to assess how pre-hospitalization medical treatments modify the relationship between PM<10 μm in aerodynamic diameter (PM10) and the risk of cardiorespiratory admission.

METHODS

We gathered information on hospitalizations for cardiorespiratory causes, together with pre-admission pharmacological treatments, that occurred during 2005 in seven cities located in Lombardy (Northern Italy). City-specific PM10 concentrations were measured at fixed monitoring stations. Each treatment of interest was analyzed separately through a case-only approach, using generalized additive models accounting for sex, age, comorbidities, temperature and simultaneous intake of other drugs. Analyses were stratified by season and, if useful, by age and sex.

RESULTS

Our results showed a higher effect size for PM10 on respiratory admissions in subjects treated with theophylline (Odds Ratio (OR) of treatment for an increment of 10 μg/m(3) in PM10 concentration: 1.119; 95% Confidence Interval (CI): 1.013-1.237), while for cardiovascular admissions treatment with cardiac therapy (OR: 0.967, 95% CI: 0.940-0.995) and lipid modifying agents (OR: 0.962, 95% CI: 0.931-0.995) emerged as a protective factor, especially during the warm season. Evidence of a protective effect against the pollutant was found for glucocorticoids and respiratory admissions.

CONCLUSIONS

Our study showed that the treatment with cardiac therapy and lipid modifying agents might mitigate the effect of PM10 on cardiovascular health, while the use of theophylline seems to enhance the effect of the pollutant, possibly due to confounding by indication. It is desirable to extend the analyses to a larger population.