Fine particulate matter (PM2.5) inhalation-induced alterations in the plasma lipidome as promoters of vascular inflammation and insulin resistance

The impact of environmental pollution on metabolic health and the risk of non-communicable chronic metabolic diseases in humans

AIMS

This review aims to provide a comprehensive overview to understand the role of pollution in the development of noncommunicable diseases (NCDs), with a focus on metabolic diseases.

DATA SYNTHESIS

In the context of NCDs, the incidence of metabolic diseases such as obesity and diabetes are increasing at an alarming rate. In addition to the well-known role of the so-called "obesogenic" environment, characterized by unhealthy diet and physical inactivity, great attention has been paid in recent years to the effects of pollution. Indeed, progressive urbanization has been associated with increased exposure to pollutants. The harmful effects of some pollutants on the endocrine system have been known for decades, but data on the metabolic impact of pollution are rather recent. Pollution in its various forms promotes a systemic inflammatory state, insulin resistance, and oxidative stress, which appear to be closely associated with increased risk of NCD, particularly obesity and diabetes.

CONCLUSIONS

In conclusion, urbanization has so far had a predominantly negative impact on collective health, but a better understanding of the mechanisms linking pollution to metabolic health is crucial to implement preventive strategies, including careful urban planning to improve community health, understood not only as the absence of disease but also as psychological and social well-being, overcoming the risks associated with urbanization.

Associations between long-term exposure to ultrafine particles and type 2 diabetes: A large-scale, multicenter study in China

Few studies have examined the associations between long-term exposure to ultrafine particles (UFP) and type 2 diabetes (T2DM). This study aimed to investigate the impact of long-term UFP exposure on diabetes prevalence and stages, as well as glycemic markers, using data from a large multi-center cohort collected from 2017 to 2021. The health outcomes assessed included diabetes prevalence and stages (normoglycemia, prediabetes, and diabetes), as well as glycemic markers, i.e., fasting blood glucose (FPG) and glycated hemoglobin (HbA1c). The three-year average UFP concentration prior to baseline was used as the long-term UFP exposure level. This cross-sectional study included 93,990 participants, with a diabetes prevalence of 10.97 %. An interquartile range increase in UFP was significantly associated with diabetes prevalence and stages, with ORs of 1.20 (95 % CI: 1.14, 1.26) and 1.11 (95 % CI: 1.07, 1.44), respectively. Specifically, for comparison between normoglycemia and prediabetes, and between prediabetes and diabetes, the corresponding ORs were 1.01 (95 % CI: 0.96, 1.04) and 1.24 (95 % CI: 1.17, 1.31), respectively. UFP exposure was also significantly associated with elevated levels of FPG and HbA1c. These findings suggest that long-term UFP exposure may be a potential risk factor for diabetes with larger risks in the prediabetes population.

Evaluation of the effects of short-term PM2.5 exposure on triglyceride-glucose metrics in a population in eastern China

CONTEXT

The triglyceride-glucose (TyG) index, a novel health indicator, has been widely employed to assess insulin resistance (IR). However, its relationship with fine particulate matter (PM) exposure remains inadequately investigated.

OBJECTIVE

This study endeavors to probe the association between PM2.5 and TyG within the population of eastern China and to determine whether there are disparities in this association among diverse subgroups.

METHODS

We conducted an ecological study on a cohort comprising 39,011 individuals who had undergone at least two physical examinations between 2017 and 2019 at the First Affiliated Hospital of Nanjing Medical University, China. TyG levels concerning short-term PM2.5 exposure were examined using a generalized additive model.

RESULTS

In the overall population, at lags of 0-7 and 0-14 days in the single-pollutant model, it was observed that a 10 µg/m3 rise in PM2.5 corresponded to a 0.0021 elevation in TyG levels. In the multi-pollutant models, at 0-7 and 0-14 days lags, a comparable increase in PM2.5 resulted in an increase in TyG of 0.0073 and 0.0044, respectively. The association remained significant in the subgroup analyses.

CONCLUSION

PM2.5 exposure is related to the TyG index. Controlling air pollution might contribute to maintainin normal lipid metabolism function.

Air pollution exposure and prevalence of non-alcoholic fatty liver disease and related cirrhosis: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVE

A systematic review and meta-analysis were used to investigate the relationship between air pollution exposure and the prevalence of non-alcoholic fatty liver disease (NAFLD) and its related cirrhosis. Through this study, we hope to clarify the potential public health risks of air pollution as an environmental exposure factor.

METHODS

Through a comprehensive and systematic search of the EMBASE, PubMed, Web of Science, and Cochrane library databases, studies published up to March 30, 2024, that met the eligibility criteria were identified. The meta-analysis aimed to determine the association between air pollution exposure and NAFLD risk. Subgroup analyses were conducted based on regional economic development after adjusting for confounding factors. The combined odds ratio (OR) was calculated, publication bias was assessed using funnel plots, and consideration was given to heterogeneity among study-specific relative risks.

RESULTS

This review included 14 observational studies (including 7 cohort studies and 7 cross-sectional studies) involving 43,475,41 participants. The pooled analysis showed that PM2.5, NOx, PM10, PM2.5-10, passive smoking, PM1, and air pollution from solid fuels were positively associated with the incidence and prevalence of NAFLD and its related cirrhosis. The risk ratios for PM2.5, NOx, PM10, PM2.5-10, passive smoking, and air pollution from solid fuels for NAFLD and its related cirrhosis were 1.33 (95 % CI: 1.25, 1.42), 1.19 (95 % CI: 1.14, 1.23), 1.27 (95 % CI: 1.05, 1.55), 1.05 (95 % CI: 1.00, 1.11), 1.53 (95 % CI: 1.12, 2.09), 1.50 (95 % CI: 0.86, 2.63), and 1.18 (95 % CI: 0.85, 1.63), respectively. In contrast, the risk ratio for O3 was 0.75 (95 % CI: 0.69, 0.83), suggesting that O3 may lower the incidence and prevalence of NAFLD and its related cirrhosis. We also conducted subgroup analyses based on the level of national development to examine the impact of PM2.5 on NAFLD and its related cirrhosis. The results showed that the risk of NAFLD and its related cirrhosis associated with PM2.5 in developing countries was 1.41 (95 % CI: 1.29, 1.53), which was higher than 1.20 (95 % CI: 1.12, 1.29) in developed countries.

CONCLUSION

The study findings show that PM2.5, NOx, PM10, PM2.5-10, passive smoking, PM1, and air pollution from solid fuels can increase an individual's risk of developing NAFLD and its related cirrhosis; while O3 can reduce the risk. In developing countries, the risk level of NAFLD and its related cirrhosis due to PM2.5 is higher than that in developed countries.

Cellular and metabolic impacts of repeated sub-acute exposures to biomass-burning extracts in vitro

The increasing exposure to biomass-burning emissions underscores the need to understand their toxicological impacts on human health. In this study, we developed a laboratory model to evaluate the effects of single and repeated sub-acute exposures to water-soluble wood tar (WT) extracts, a product of biomass burning, on human lung, liver, and immune cells. Using representative cell lines for different tissues, we examined the cytotoxic effects under conditions mimicking sub-acute environmental exposure levels relevant to humans. Our findings indicate that repeated sub-acute exposures to water-soluble WT extracts significantly enhance the inflammatory response, evidenced by increased IL6, IL8, and TNFa cytokine levels, compared to a single exposure. Additionally, oxidative stress responses were more pronounced with increased lipid peroxidation and HMOX1, GCLC and CYP1A1 gene expression following repeated exposures. Metabolomics analyses of polar and lipid metabolites revealed changes related to energy production and consumption that emerge even after a single exposure at sub-acute levels and vary across different cell types representing the different tissues. Impaired cellular respiration, measured by oxygen consumption rate, corroborates the observed changes. These results provide important insights into the cellular mechanisms driving the response to biomass-burning exposure and highlight the potential health risks associated with sub-acute exposure to environmental pollutants.

Association Between Environmental Air Pollution and Thyroid Cancer and Nodules: A Systematic Review

Background: The global incidence of thyroid cancer has increased over the past several decades. While this increase is partially due to increased detection, environmental pollutants have also emerged as a possible contributing factor. Our goal was to perform a systematic review to assess the relationship between environmental air pollution and thyroid cancer. Methods: Systematic literature search was performed using PubMed, EMBASE, Cochrane Library, Web of Science, and Scopus databases for original articles published prior to March 2024, investigating outdoor air pollution and thyroid cancer/nodules (PROSPERO CRD42024517624). Inclusion criteria included quantitative reporting of pollutant levels and effect size. Specific pollutants included ozone (O3), particulate matter less than 2.5 (PM2.5) or 10 microns in diameter (PM10), sulfur dioxide (SO2), nitric oxides (NOx), carbon monoxide (CO), and polyaromatic hydrocarbons (PAHs). Study design, sample size, pollution assessment method, covariates, and strength/direction of associations between pollutants and thyroid cancer/nodule detection were extracted, and descriptive synthesis was utilized to summarize pertinent findings. Risk of bias was assessed using the National Heart, Lung, and Blood Institute quality assessment tool. Results: Of 1294 identified studies, 11 met inclusion criteria. Over 6 million patients from diverse regions were represented across studies. Pollutants studied included O3 in 5 studies; PM2.5, PM10, SO2, and NOx in 3 studies; unspecified PM and CO in 2 studies; and PAHs in 1 study. Primary outcome was thyroid cancer diagnosis among 9 studies and thyroid nodule detection in 2. All studies examining NOx and O3 reported increased risks ranging from 1.03 to 1.5-fold and 1.1 to 1.3-fold, respectively. Both studies assessing PM2.5 reported 1.18 to 1.23-fold increased odds of thyroid cancer diagnosis, and the magnitude of association increased with increasing duration or concentration of PM2.5 Inconsistent results were observed for levels of CO, PM10, and SO2. Conclusion: While an emerging body of literature suggests a potential association between air pollution and thyroid cancer, the quality of evidence is limited by study design constraints, variability in exposure assessment, and inconsistent adjustment for potential confounding factors. The heterogeneity in study designs and methodologies present challenges in interpreting results, underscoring the need for standardized approaches in future research.

Diabetes mellitus-Progress and opportunities in the evolving epidemic

Diabetes, a complex multisystem metabolic disorder characterized by hyperglycemia, leads to complications that reduce quality of life and increase mortality. Diabetes pathophysiology includes dysfunction of beta cells, adipose tissue, skeletal muscle, and liver. Type 1 diabetes (T1D) results from immune-mediated beta cell destruction. The more prevalent type 2 diabetes (T2D) is a heterogeneous disorder characterized by varying degrees of beta cell dysfunction in concert with insulin resistance. The strong association between obesity and T2D involves pathways regulated by the central nervous system governing food intake and energy expenditure, integrating inputs from peripheral organs and the environment. The risk of developing diabetes or its complications represents interactions between genetic susceptibility and environmental factors, including the availability of nutritious food and other social determinants of health. This perspective reviews recent advances in understanding the pathophysiology and treatment of diabetes and its complications, which could alter the course of this prevalent disorder.

The association between air pollution and obesity: an umbrella review of meta-analyses and systematic reviews

The objective of this umbrella review was to investigate comprehensive and synthesized evidence of the association between ambient air pollution and obesity based on the current systematic reviews and meta-analyses. Related studies from databases including PubMed, EMBASE, Web of Science, and the Cochrane Library, published before July 16, 2023, were considered in the analysis. All selected systematic reviews and meta-analyses were included in accordance with PRISMA guidelines. The risk of bias and the methodological quality were evaluated using the AMSTAR 2 tool. The protocol for this umbrella review was documented in PROSPERO with the registration number: CRD42023450191. This umbrella review identified 7 studies, including 5 meta-analyses and 2 systematic reviews, to assess the impacts of air pollutants on obesity. Commonly examined air pollutants included PM1, PM2.5, PM10, NO2, SO2, O3. Most of the included studies presented that air pollution exposure was positively associated with the increased risk of obesity. The impact of air pollution on obesity varied by different ambient air pollutants. This study provided compelling evidence that exposure to air pollution had a positive association with the risk of obesity. These findings further indicate the importance of strengthening air pollution prevention and control. Future studies should elucidate the possible mechanisms and pathways linking air pollution to obesity.

Inhaled Pollutants of the Gero-Exposome and Later-Life Health

Inhaled air pollutants (AirP) comprise extraordinarily diverse particles, volatiles, and gases from traffic, wildfire, cigarette smoke, dust, and various other sources. These pollutants contain numerous toxic components, which collectively differ in relative levels of components, but broadly share chemical classes. Exposure and health outcomes from AirP are complex, depending on pollutant source, duration of exposure, and socioeconomic status. We discuss examples in the current literature on organ responses to AirP, with a focus on lung, arteries, and brain. Some transcriptional responses are shared. It is well accepted that AirP contributes to Alzheimer's disease and other neurodegenerative conditions in the Gero-Exposome. However, we do not know which chemical compounds initiate these changes and how activation of these transcriptional pathways is further modified by genetics and prenatal development.

Air pollution exposure and cardiometabolic risk

The Global Burden of Disease assessment estimates that 20% of global type 2 diabetes cases are related to chronic exposure to particulate matter (PM) with a diameter of 2·5 μm or less (PM2·5). With 99% of the global population residing in areas where air pollution levels are above current WHO air quality guidelines, and increasing concern in regard to the common drivers of air pollution and climate change, there is a compelling need to understand the connection between air pollution and cardiometabolic disease, and pathways to address this preventable risk factor. This Review provides an up to date summary of the epidemiological evidence and mechanistic underpinnings linking air pollution with cardiometabolic risk. We also outline approaches to improve awareness, and discuss personal-level, community, governmental, and policy interventions to help mitigate the growing global public health risk of air pollution exposure.

Effects of short-term exercise and endurance training on skeletal muscle mitochondria damage induced by particular matter, atmospherically relevant artificial PM2.5

Introduction

This study aimed to investigate the potential of short-term aerobic exercise to mitigate skeletal muscle mitochondrial damage following ambient PM2.5 exposure, and how 12 weeks of endurance training can enhance aerobic fitness to protect against such damage.

Methods

Twenty-four male C57BL/6 J mice were split into sedentary (SED, n = 12) and endurance training (ETR, n = 12) groups. The ETR group underwent 12 weeks of training (10-15 m/min, 60 min/day, 4 times/week), confirmed by an Endurance Exercise Capacity (EEC) test. Post-initial training, the SED group was further divided into SSED (SED and sedentary, n = 6) and SPE (SED and PM2.5 + Exercise, n = 6). Similarly, the ETR group was divided into EEX (ETR and Exercise, n = 6) and EPE (ETR and PM2.5 + Exercise, n = 6). These groups underwent 1 week of atmospherically relevant artificial PM2.5 exposure and treadmill running (3 times/week). Following treatments, an EEC test was conducted, and mice were sacrificed for blood and skeletal muscle extraction. Blood samples were analyzed for oxidative stress indicators, while skeletal muscles were assessed for mitochondrial oxidative metabolism, antioxidant capacity, and mitochondrial damage using western blot and transmission electron microscopy (TEM).

Results

After 12 weeks of endurance training, the EEC significantly increased (p < 0.000) in the ETR group compared to the SED group. Following a one-week comparison among the four groups with atmospherically relevant artificial PM2.5 exposure and exercise treatment post-endurance training, the EEX group showed improvements in EEC, oxidative metabolism, mitochondrial dynamics, and antioxidant functions. Conversely, these factors decreased in the EPE group compared to the EEX. Additionally, within the SPE group, exercise effects were evident in HK2, LDH, SOD2, and GPX4, while no impact of short-term exercise was observed in all other factors. TEM images revealed no evidence of mitochondrial damage in both the SED and EEX groups, while the majority of mitochondria were damaged in the SPE group. The EPE group also exhibited damaged mitochondria, although significantly less than the SPE group.

Conclusion

Atmospherically relevant artificial PM2.5 exposure can elevate oxidative stress, potentially disrupting the benefits of short-term endurance exercise and leading to mitochondrial damage. Nonetheless, increased aerobic fitness through endurance training can mitigate PM2.5-induced mitochondrial damage.

Exposome in ischaemic heart disease: beyond traditional risk factors

Ischaemic heart disease represents the leading cause of morbidity and mortality, typically induced by the detrimental effects of risk factors on the cardiovascular system. Although preventive interventions tackling conventional risk factors have helped to reduce the incidence of ischaemic heart disease, it remains a major cause of death worldwide. Thus, attention is now shifting to non-traditional risk factors in the built, natural, and social environments that collectively contribute substantially to the disease burden and perpetuate residual risk. Of importance, these complex factors interact non-linearly and in unpredictable ways to often enhance the detrimental effects attributable to a single or collection of these factors. For this reason, a new paradigm called the 'exposome' has recently been introduced by epidemiologists in order to define the totality of exposure to these new risk factors. The purpose of this review is to outline how these emerging risk factors may interact and contribute to the occurrence of ischaemic heart disease, with a particular attention on the impact of long-term exposure to different environmental pollutants, socioeconomic and psychological factors, along with infectious diseases such as influenza and COVID-19. Moreover, potential mitigation strategies for both individuals and communities will be discussed.

Particulate Matter and Its Impact on Macrophages: Unraveling the Cellular Response for Environmental Health

Particulate matter (PM) imposes a significant impact to environmental health with deleterious effects on the human pulmonary and cardiovascular systems. Macrophages (Mφ), key immune cells in lung tissues, have a prominent role in responding to inhaled cells, accommodating inflammation, and influencing tissue repair processes. Elucidating the critical cellular responses of Mφ to PM exposure is essential to understand the mechanisms underlying PM-induced health effects. The present review aims to give a glimpse on literature about the PM interaction with Mφ, triggering the cellular events causing the inflammation, oxidative stress (OS) and tissue damage. The present paper reviews the different pathways involved in Mφ activation upon PM exposure, including phagocytosis, intracellular signaling cascades, and the release of pro-inflammatory mediators. Potential therapeutic strategies targeting Mφ-mediated responses to reduce PM-induced health effects are also discussed. Overall, unraveling the complex interplay between PM and Mφ sheds light on new avenues for environmental health research and promises to develop targeted interventions to reduce the burden of PM-related diseases on global health.

The Influence of Airborne Particulate Matter on the Risk of Gestational Diabetes Mellitus: A Large Retrospective Study in Chongqing, China

Emerging research findings suggest that airborne particulate matter might be a risk factor for gestational diabetes mellitus (GDM). However, the concentration-response relationships and the susceptible time windows for different types of particulate matter may vary. In this retrospective analysis, we employ a novel robust approach to assess the crucial time windows regarding the prevalence of GDM and to distinguish the susceptibility of three GDM subtypes to air pollution exposure. This study included 16,303 pregnant women who received routine antenatal care in 2018-2021 at the Maternal and Child Health Hospital in Chongqing, China. In total, 2482 women (15.2%) were diagnosed with GDM. We assessed the individual daily average exposure to air pollution, including PM2.5, PM10, O3, NO2, SO2, and CO based on the volunteers' addresses. We used high-accuracy gridded air pollution data generated by machine learning models to assess particulate matter per maternal exposure levels. We further analyzed the association of pre-pregnancy, early, and mid-pregnancy exposure to environmental pollutants using a generalized additive model (GAM) and distributed lag nonlinear models (DLNMs) to analyze the association between exposure at specific gestational weeks and the risk of GDM. We observed that, during the first trimester, per IQR increases for PM10 and PM2.5 exposure were associated with increased GDM risk (PM10: OR = 1.19, 95%CI: 1.07~1.33; PM2.5: OR = 1.32, 95%CI: 1.15~1.50) and isolated post-load hyperglycemia (GDM-IPH) risk (PM10: OR = 1.23, 95%CI: 1.09~1.39; PM2.5: OR = 1.38, 95%CI: 1.18~1.61). Second-trimester O3 exposure was positively correlated with the associated risk of GDM, while pre-pregnancy and first-trimester exposure was negatively associated with the risk of GDM-IPH. Exposure to SO2 in the second trimester was negatively associated with the risk of GDM-IPH. However, there were no observed associations between NO2 and CO exposure and the risk of GDM and its subgroups. Our results suggest that maternal exposure to particulate matter during early pregnancy and exposure to O3 in the second trimester might increase the risk of GDM, and GDM-IPH is the susceptible GDM subtype to airborne particulate matter exposure.

The burden of ischemic heart disease attributable to ambient and household particulate matter pollution, 1990-2019: a global analysis

Elevated risk of ischemic heart disease (IHD) is associated with exposure to fine particulate matter. However, there is limited data on trends and comparisons in the global burden of IHD due to household air pollution from solid fuels (HAP) and ambient particulate matter pollution (APMP), particularly in regions of varying socio-economic levels. Based on the Global Burden of Disease Study 2019 (GBD 2019), we obtained age-standardized mortality rates (ASMR) and age-standardized disability-adjusted life years (ASDR) of IHD due to APMP and HAP from 1990 to 2019. Trends in the burden of IHD attributable to APMP and HAP during the period 1990 to 2019 were calculated by Joinpoint models. We estimated the relationship between ASMR with the socio-demographic indexes (SDI) and the health care accessibility and quality (HAQ) index by the Loess regression model. In 2019, the global burden of IHD ASMR attributed to APMP stabilized, but the most significant increases were observed in low-middle SDI regions. The global IHD ASMR attributed to APMP was 16.60 [95% Uncertainty Interval (UI), 13.61 to 19.44] per 100,000 population, with the highest APMP burden in middle SDI regions. From 1990 to 2019, the global ASMR for HAP-attributable IHD declined. The global ASMR of IHD attributable to HAP in 2019 was 6.30 (95% UI, 4.28 to 8.80) per 100,000 population, with the highest burden observed in the low SDI regions. From 1990 to 2019, the global burden of ASMR and ASDR of IHD attributable to APMP showed stabilization, whereas the HAP burden exhibited a decrease. There are a large burden of APMP particularly in middle SDI countries and a higher burden of HAP in low SDI countries. The burden of IHD due to APMP and HAP in men, the elderly, and populations in low, medium, and low SDI regions should be noticed.

Ambient fine particulate matter and pregnancy outcomes: An umbrella review

The available evidence on the effects of ambient fine particulate matter (PM2.5) and pregnancy outcomes (birth outcomes and pregnancy complications) has increased substantially. The purpose of this umbrella review is to refine the evidence of the association between birth outcome (birth defects) and PM2.5; and summarize the credibility of existing research on the association between pregnancy complications and PM2.5. We searched PubMed, Web of Science, Embase, and Cochrane databases for relevant systematic reviews and meta-analyses up to March 16, 2022 in accordance with PRISMA guidelines. Two independent investigators conducted data extraction. AMSTAR 2 and GRADE assessment criteria were used to evaluate the methodological and evidence quality. We performed subgroup analyses by trimesters of pregnancy. The review protocol for this study has been registered in PROSPERO (CRD42022325550). This umbrella review identified a total of 41 systematic reviews, including 28 articles evaluating the influence of PM2.5 on birth outcomes and 13 on pregnancy complications. Positive associations between perinatal PM2.5 exposure and adverse birth outcomes were found, including low birth weight, preterm birth, stillbirth, small for gestational age, and birth defects. Pregnant women exposed to PM2.5 had a significantly higher risk of developing hypertensive disorder of pregnancy, gestational diabetes mellitus, gestational hypertension, and preeclampsia. The findings of subgroup analysis demonstrated that the effects of ambient PM2.5 exposure on pregnancy outcomes varied by trimesters. The findings of this extensive umbrella review provide convincing proof that exposure to ambient PM2.5 raises the risks of unfavorable birth outcomes and pregnancy complications. Some associations show considerable disparity between trimesters. These findings have implications for strengthen perinatal health care on air pollution and improving intergenerational equity.

Association between long-term exposure to low level air pollutants and incident end-stage kidney disease in the UK Biobank: A prospective cohort

BACKGROUND

Previous studies suggest that air pollution can increase the risk of incident chronic kidney disease (CKD). However, the association between end-stage kidney disease (ESKD) and co-exposure to relatively low-level air pollutants remains unclear.

METHODS

A prospective cohort was designed based on UK Biobank. From 1 January 2010 to 12 November 2021, 453,347 participants were followed up over a median of 11.87 years. Principal component analysis was used to identify major patterns of five air pollutants, including PM2.5, PM2.5-10, PM10, NO2, and NOx. Sub-distribution hazards models were used to estimate the associations between air pollution, individually or jointly, and incident ESKD, CKD, and all-cause death, respectively.

RESULTS

Principal component analysis identified two principal components, namely RC1 (PM2.5, NO2, and NOx) and RC2 (PM2.5-10 and PM10). An elevated risk of incident ESKD was associated with an interquartile range (IQR) increase in PM2.5 (hazard ratio: 1.11, 95% confidence interval: 1.02-1.22), NO2 (1.16, 1.04-1.30), NOx (1.08, 1.00-1.17), and RC1 (1.12, 1.02-1.23). An elevated risk of incident CKD was associated with an IQR increase in PM2.5 (1.05, 1.03-1.07), NO2 (1.04, 1.02-1.06), NOx (1.03, 1.02-1.05), and RC1 (1.04, 1.02-1.06). An increased risk of all-cause mortality was associated with an IQR increase in PM2.5 (1.02, 1.00-1.04). Restricted cubic spline analyses indicated a monotonic elevating association of PM2.5, NO2, NOx, and RC1 with ESKD incidence.

CONCLUSIONS

Long-term exposure to PM2.5, NO2, NOx, and their complex was associated with elevated ESKD incidence, even at relatively lower levels of air pollution.

Tracing the plasma kallikrein-kinin system-activating component in the atmospheric particulate matter with different origins

Atmospheric particulate matter (PM) perturbs hematological homeostasis by targeting the plasma kallikrein-kinin system (KKS), causing a cascade of zymogen activation events. However, the causative components involved in PM-induced hematological effects are largely unknown. Herein, the standard reference materials (SRMs) of atmospheric PM, including emissions from the diesel (2975), urban (1648a), and bituminous coal (2693), were screened for their effects on plasma KKS activation, and the effective constituent contributing to PM-induced KKS activation was further explored by fraction isolation and chemical analysis. The effects of three SRMs on KKS activation followed the order of 2975 > 1648a > 2693, wherein the fractions of 2975 isolated by acetone and water, together with the insoluble particulate residues, exerted significant perturbations in the hematological homeostasis. The soot contents in the SRMs and corresponding isolated fractions matched well with their hematological effects, and the KKS activation could be dependent on the soot surface oxidation degree. This study, for the first time, uncovered the soot content in atmospheric PM with different origins contributed to the distinct effects on plasma KKS activation. The finding would be of utmost importance for the health risk assessment on inhaled airborne fine PM, given its inevitable contact with human circulatory system.

Fine particulate matter (PM2.5)-induced pulmonary oxidative stress contributes to increases in glucose intolerance and insulin resistance in a mouse model of circadian dyssynchrony

Results of human and animal studies independently suggest that either ambient fine particulate matter (PM2.5) air pollution exposure or a disturbed circadian rhythm (circadian dyssynchrony) are important contributing factors to the rapidly evolving type-2-diabetes (T2D) epidemic. The objective of this study is to investigate whether circadian dyssynchrony increases the susceptibility to PM2.5 and how PM2.5 affects metabolic health in circadian dyssynchrony. We examined systemic and organ-specific changes in glucose homeostasis and insulin sensitivity in mice maintained on a regular (12/12 h light/dark) or disrupted (18/6 h light/dark, light-induced circadian dyssynchrony, LICD) light cycle exposed to air or concentrated PM2.5 (CAP, 6 h/day, 30 days). Exposures during Zeitgeber ZT3-9 or ZT11-17 (Zeitgeber in circadian time, ZT0 = begin of light cycle) tested for time-of-day PM2.5 sensitivity (chronotoxicity). Mice transgenic for lung-specific overexpression of extracellular superoxide dismutase (ecSOD-Tg) were used to assess the contribution of CAP-induced pulmonary oxidative stress. Both, CAP exposure from ZT3-9 or ZT11-17, decreased glucose tolerance and insulin sensitivity in male mice with LICD, but not in female mice or in mice kept on a regular light cycle. Although changes in glucose homeostasis in CAP-exposed male mice with LICD were not associated with obesity, they were accompanied by white adipose tissue (WAT) inflammation, impaired insulin signaling in skeletal muscle and liver, and systemic and pulmonary oxidative stress. Preventing CAP-induced oxidative stress in the lungs mitigated the CAP-induced decrease in glucose tolerance and insulin sensitivity in LICD. Our results demonstrate that circadian dyssynchrony is a novel susceptibility state for PM2.5 and suggest that PM2.5 by inducing pulmonary oxidative stress increases glucose intolerance and insulin resistance in circadian dyssynchrony.

Subchronic co-exposure to particulate matter and fructose-rich-diet induces insulin resistance in male Sprague Dawley rats

Insulin resistance (IR) and metabolic disorders are non-pulmonary adverse effects induced by fine particulate matter (PM_2.5) exposure. The worldwide pandemic of high fructose sweeteners and fat rich modern diets, also contribute to IR development. We investigated some of the underlying effects of IR, altered biochemical insulin action and Insulin/AKT pathway biomarkers. Male Sprague Dawley rats were subchronically exposed to filtered air, PM_2.5, a fructose rich diet (FRD), or PM_2.5 + FRD. Exposure to PM_2.5 or FRD alone did not induce metabolic changes. However, PM_2.5 + FRD induced leptin release, systemic hyperinsulinemia, and Insulin/AKT dysregulation in insulin-sensitive tissues preceded by altered AT₁R levels. Histological damage and increased HOMA-IR were also observed from PM_2.5 + FRD co-exposure. Our results indicate that the concomitant exposure to a ubiquitous environmental pollutant, such as PM_2.5, and a metabolic disease risk factor, a FRD, can contribute to the metabolic disorder pandemic occurring in highly polluted locations.

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

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

Fine Particulate Matter (PM2.5)-Induced Pulmonary Oxidative Stress Contributes to Changes in the Plasma Lipidome and Liver Transcriptome in Mice

Fine particulate matter (PM2.5) air pollution exposure increases the cardiovascular disease risk. Although the specific mechanisms remain elusive, it is thought that PM2.5-induced oxidative stress and endothelial dysfunction contribute to this pathogenesis. Our previous findings indicate that PM2.5 impairs vascular health via a circulating factor and that plasma lipid changes contribute to the observed vascular effects. In the current study, we extend on these findings by further characterizing PM2.5-induced changes in circulating lipids and examining whether the observed changes were accompanied by related alterations in the liver transcriptome. To address the role of pulmonary oxidative stress, we exposed wild-type (WT) mice and mice that overexpress extracellular superoxide dismutase (ecSOD-Tg) in the lungs to concentrated ambient PM2.5 (CAP, 9 days). We found that CAP decreased circulating complex lipids and increased free fatty acids and acylcarnitines in WT, but not ecSOD-Tg mice. These plasma lipid changes were accompanied by transcriptional changes in genes that regulate lipid metabolism (e.g., upregulation of lipid biosynthesis, downregulation of mitochondrial/peroxisomal FA metabolism) in the liver. The CAP-induced changes in lipid homeostasis and liver transcriptome were accompanied by pulmonary but not hepatic oxidative stress and were largely absent in ecSOD-Tg mice. Our results suggest that PM2.5 impacts hepatic lipid metabolism; however, it remains unclear whether the transcriptional changes in the liver contribute to PM2.5-induced changes in plasma lipids. Regardless, PM2.5-induced changes in the plasma lipidome and hepatic transcriptome are, at least in part, mediated by pulmonary oxidative stress.

Critical Overview on Endocrine Disruptors in Diabetes Mellitus

Diabetes mellitus is a major public health problem in all countries due to its high human and economic burden. Major metabolic alterations are associated with the chronic hyperglycemia that characterizes diabetes and causes devastating complications, including retinopathy, kidney failure, coronary disease and increased cardiovascular mortality. The most common form is type 2 diabetes (T2D) accounting for 90 to 95% of the cases. These chronic metabolic disorders are heterogeneous to which genetic factors contribute, but so do prenatal and postnatal life environmental factors including a sedentary lifestyle, overweight, and obesity. However, these classical risk factors alone cannot explain the rapid evolution of the prevalence of T2D and the high prevalence of type 1 diabetes in particular areas. Among environmental factors, we are in fact exposed to a growing amount of chemical molecules produced by our industries or by our way of life. In this narrative review, we aim to give a critical overview of the role of these pollutants that can interfere with our endocrine system, the so-called endocrine-disrupting chemicals (EDCs), in the pathophysiology of diabetes and metabolic disorders.

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

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

Long-term effect of submicronic particulate matter (PM1) and intermodal particulate matter (PM1-2.5) on incident dyslipidemia in China: A nationwide 5-year cohort study

BACKGROUND

There is insufficient evidence of associations between incident dyslipidemia with PM₁ (submicronic particulate matter) and PM_1-2.5 (intermodal particulate matter) in the middle-aged and elderly. We aimed to determine the long-term effects of PM₁ and PM_1-2.5 on incident dyslipidemia respectively.

METHODS

We studied 6976 individuals aged ≥45 from the China Health and Retirement Longitudinal Study from 2013 to 2018. The concentrations of particular matter (PM) for every individual's address were evaluated using a satellite-based spatiotemporal model. Dyslipidemia was evaluated by self-reported. The generalized linear mixed model was applied to quantify the correlations between PM and incident dyslipidemia.

RESULTS

After a 5-year follow-up, 333 (4.77%) participants developed dyslipidemia. Per 10 μg/m³ uptick in four-year average concentrations of PMs (PM₁ and PM_1-2.5) corresponded to 1.11 [95% confidence interval (CI): 1.01-1.23)] and 1.23 (95% CI: 1.06-1.43) fold risks of incident dyslipidemia. Nonlinear exposure-response curves were observed between PM and incident dyslipidemia. The effect size of PM₁ on incident dyslipidemia was slightly higher in males [1.14 (95% CI: 0.98-1.32) vs. 1.04 (95% CI: 0.89-1.21)], the elderly [1.23 (95% CI: 1.04-1.45) vs. 1.03 (95% CI: 0.91-1.17)], people with less than primary school education [1.12 (95% CI: 0.94-1.33) vs. 1.08 (95% CI: 0.94-1.23)], and solid cooking fuel users [1.17 (95% CI: 1.00-1.36) vs. 1.06 (95% CI: 0.93-1.21)], however, the difference was not statistically significant (Z = -0.82, P = 0.413; Z = -1.66, P = 0.097; Z = 0.32, P = 0.752; Z = -0.89, P = 0.372).

CONCLUSIONS

Long-term exposure to PM₁ and PM_1-2.5 were linked with an increased morbidity of dyslipidemia in the middle-aged and elderly population. Males, the elderly, and solid cooking fuel users had higher risk. Further studies would be warranted to establish an accurate reference value of PM to mitigate growing dyslipidemia.

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

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

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

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

The underlying mechanism of PM2.5-induced ischemic stroke

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

The Physiological Effects of Air Pollution: Particulate Matter, Physiology and Disease

Nine out of 10 people breathe air that does not meet World Health Organization pollution limits. Air pollutants include gasses and particulate matter and collectively are responsible for ~8 million annual deaths. Particulate matter is the most dangerous form of air pollution, causing inflammatory and oxidative tissue damage. A deeper understanding of the physiological effects of particulate matter is needed for effective disease prevention and treatment. This review will summarize the impact of particulate matter on physiological systems, and where possible will refer to apposite epidemiological and toxicological studies. By discussing a broad cross-section of available data, we hope this review appeals to a wide readership and provides some insight on the impacts of particulate matter on human health.

Exposure to fine particulate matter partially counteract adaptations on glucose metabolism, oxidative stress, and inflammation of endurance exercise in rats

BACKGROUND

Long-term exposure to air pollution triggers metabolic alterations along with oxidative stress and inflammation, while exercise interventions are widely used to improve those parameters.

OBJECTIVE

Our study aimed to determine the effects of subchronic exposure to particulate matter 2.5 (PM_2.5) and endurance exercise training on glucose metabolism, oxidative stress, and inflammation of the heart and gastrocnemius muscle of rats.

MATERIAL AND METHODS

Thirty-two male Wistar rats were assigned to 4 experimental groups: Untrained; Endurance training (ET); Untrained + PM_2.5; Endurance training + PM_2.5. Rats exposed to air pollution received 50 µg of PM_2.5 via intranasal instillation daily for 12 weeks. Exercised groups underwent endurance training, consisting in running on an electronic treadmill (70% of maximal capacity, 5 days/week, 5 times/week) for 12 weeks. Glucose metabolism markers, redox state, and inflammatory variables were evaluated in the heart and gastrocnemius muscle.

RESULTS

ET and ET + PM_2.5 group had lower body mass gain and higher exercise capacity, and higher glycogen concentration in the heart and gastrocnemius muscle. In the heart, ET and ET + PM_2.5 groups had higher levels of GSH, and lower TBARS and TNF-α concentrations. In the gastrocnemius muscle, the ET group showed higher leptin and lower TBARS and IL-1β concentrations, ET and ET + PM_2.5 showed higher superoxide dismutase activity and ROS content.

CONCLUSION

PM_2.5 exposure partially blunts metabolic and inflammatory adaptations in heart and gastrocnemius muscle tissues induced by exercise training.

Long-term PM0.1 exposure and human blood lipid metabolism: New insight from the 33-community study in China

Ambient particles with aerodynamic diameter <0.1 μm (PM_0.1) have been suggested to have significant health impact. However, studies on the association between long-term PM_0.1 exposure and human blood lipid metabolism are still limited. This study was aimed to evaluate such association based on multiple lipid biomarkers and dyslipidemia indicators. We matched the 2006-2009 average PM_0.1 concentration simulated using the neural-network model following the WRF-Chem model with the clinical and questionnaire data of 15,477 adults randomly recruited from 33 communities in Northeast China in 2009. After controlling for social demographic and behavior confounders, we assessed the association of PM_0.1 concentration with multiple lipid biomarkers and dyslipidemia indicators using generalized linear mixed-effect models. Effect modification by various social demographic and behavior factors was examined. We found that each interquartile range increase in PM_0.1 concentration was associated with a 5.75 (95% Confidence interval, 3.24-8.25) mg/dl and a 6.05 (2.85-9.25) mg/dl increase in the serum level of total cholesterol and LDL-C, respectively. This increment was also associated with an odds ratio of 1.25 (1.10-1.42) for overall dyslipidemias, 1.41 (1.16, 1.73) for hypercholesterolemia, and 1.90 (1.39, 2.61) for hyperbetalipoproteinemia. Additionally, we found generally greater effect estimates among the younger participants and those with lower income or with certain behaviors such as high-fat diet. The deleterious effect of long-term PM_0.1 exposure on lipid metabolism may make it an important toxic chemical to be targeted by future preventive strategies.

Acute cardiovascular effects of inhaled ambient particulate matter: Chemical composition-related oxidative stress, endothelin-1, blood pressure, and ST-segment changes in Wistar rats

Short-term increases in particulate matter (PM) are associated with heightened morbidity and mortality from cardiovascular causes. Inhalation of PM is known to increase endothelin (ET)-1 levels. Yet, less is known about particle composition-related changes at the molecular level including the endothelinergic system and relationship with cardiovascular function changes. In this work, adult Wistar male rats were exposed for 4 h by nose-only inhalation to clean air, Ottawa urban particles (EHC-93, 48 mg/m³) and water-leached (EHC-93L, 49 mg/m³) particles, to examine the effect of particle compositional changes on oxidative stress, circulating ETs, blood pressure, and heart electrophysiology. Particle deposition in the respiratory compartment was estimated at 85 μg (25 ng/cm²). Lung cell proliferation was low in both treatment groups, indicating absence of acute injury. Inhalation of EHC-93 caused statistically significant elevations (p < 0.05) of oxidative stress markers, ET-1, ET-3, blood pressure, and a decrease of ST-segment duration in the ECG at 1.5 days post-exposure. Leached particles (EHC-93L) caused rapid but transient elevation (p < 0.05) of oxidative stress, ET-1, ET-2, and ET-3 at earlier time points, with no changes in blood pressure or ST-segment. These results demonstrate that inhalation of urban particles at an internal dose inadequate to cause acute lung injury can induce oxidative stress, enhance vasoactive endothelins, leading to vasopressor response, affecting cardiac electrophysiology in Wistar rats, consistent with the cardiovascular impacts of ambient particles in human populations. Change in particle potency after removal of soluble species, notably cadmium, zinc and polar organics suggests that the toxicodynamics of cardiovascular effects can be modified by physicochemical properties of particles.

Inhalation of particulate matter containing free radicals leads to decreased vascular responsiveness associated with an altered pulmonary function

Airborne particulate matter (PM) is associated with an increased risk for cardiovascular diseases. Although the goal of thermal remediation is to eliminate organic wastes through combustion, when incomplete combustion occurs, organics chemisorb to transition metals to generate PM-containing environmentally persistent free radicals (EPFRs). Similar EPFR species have been detected in PM found in diesel and gasoline exhaust, woodsmoke, and urban air. Prior in vivo studies demonstrated that EPFRs reduce cardiac function secondary to elevations in pulmonary arterial pressures. In vitro studies showed that EPFRs increase ROS and cytokines in pulmonary epithelial cells. We thus hypothesized that EPFR inhalation would promote lung inflammation and oxidative stress, leading to systemic inflammation, vascular endothelial injury, and a decline in vascular function. Mice were exposed to EPFRs for either 4 h or for 4 h/day for 10 days and lung and vascular function were assessed. After a 4-h exposure, plasma nitric oxide (NO) was reduced while endothelin-1 (ET-1) was increased, however lung function was not altered. After 10 day, plasma NO and ET-1 levels were again altered and lung tidal volume was reduced. These time course studies suggested the vasculature may be an early target of injury. To test this hypothesis, an intermediate time point of 3 days was selected. Though the mice exhibited no marked inflammation in either the lung or the blood, we did note significantly reduced endothelial function concurrent with a reduction in lung tidal volume and an elevation in annexin V protein levels in the lung. Although vascular dysfunction was not dependent upon inflammation, it may be associated with an injury at the air-blood interface. Gene expression analysis suggested roles for oxidative stress and aryl hydrocarbon receptor (Ahr) signaling. Studies probing the relationship between pulmonary oxidative stress and AhR signaling at the air-blood interface with vascular dysfunction seem warranted.NEW & NOTEWORTHY Particulate matter (PM) resulting from the combustion of organic matter is known to contribute to cardiopulmonary disease. Despite hypotheses that cardiovascular dysfunction occurring after PM exposures is secondary to lung or systemic inflammation, these studies investigating exposures to PM-containing environmentally persistent free radicals (EPFRs) demonstrate that cardiovascular dysfunction precedes pulmonary inflammation. The cardiopulmonary health consequences of EPFRs have yet to be thoroughly evaluated, especially in healthy, adult mice. Our data suggest the vasculature as a direct target of PM exposure, and our studies aimed to elucidate the mechanisms contributing to EPFR-induced vascular dysfunction.

Fine particulate matter air pollution and aortic perivascular adipose tissue: Oxidative stress, leptin, and vascular dysfunction

Exposure to fine particulate matter (PM2.5 ) air pollution increases blood pressure, induces vascular inflammation and dysfunction, and augments atherosclerosis in humans and rodents; however, the understanding of early changes that foster chronic vascular disease is incomplete. Because perivascular adipose tissue (PVAT) inflammation is implicated in chronic vascular diseases, we investigated changes in aortic PVAT following short-term air pollution exposure. Mice were exposed to HEPA-filtered or concentrated ambient PM2.5 (CAP) for 9 consecutive days, and the abundance of inflammatory, adipogenic, and adipokine gene mRNAs was measured by gene array and qRT-PCR in thoracic aortic PVAT. Responses of the isolated aorta with and without PVAT to contractile (phenylephrine, PE) and relaxant agonists (acetylcholine, ACh; sodium nitroprusside, SNP) were measured. Exposure to CAP significantly increased the urinary excretion of acrolein metabolite (3HPMA) as well as the abundance of protein-acrolein adducts (a marker of oxidative stress) in PVAT and aorta, upregulated PVAT leptin mRNA expression without changing mRNA levels of several proinflammatory genes, and induced PVAT insulin resistance. In control mice, PVAT significantly depressed PE-induced contractions-an effect that was dampened by CAP exposure. Pulmonary overexpression of extracellular dismutase (ecSOD-Tg) prevented CAP-induced effects on urinary 3HPMA levels, PVAT Lep mRNA, and alterations in PVAT and aortic function, reflecting a necessary role of pulmonary oxidative stress in all of these deleterious CAP-induced changes. More research is needed to address how exactly short-term exposure to PM2.5 perturbs PVAT and aortic function, and how these specific genes and functional changes in PVAT could lead over time to chronic inflammation, endothelial dysfunction, and atherosclerosis.

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

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