Polycyclic aromatic hydrocarbons in urban particle matter exacerbate movement disorder after ischemic stroke via potentiation of neuroinflammation

Impact of Artificial Sunlight Aging on the Respiratory Effects of Polyethylene Terephthalate Microplastics through Degradation-Mediated Terephthalic Acid Release in Male Mice

Microplastics are ubiquitous in the atmosphere, leading to human exposure through inhalation. Airborne microplastics undergo degradation due to sunlight irradiation, yet the respiratory risks associated with degraded microplastics remain poorly understood. In this study, we investigated the respiratory effects of polyethylene terephthalate (PET) degraded by artificial sunlight and created a transport and degradation model of PET for risk assessment. PET fibers were cut and subjected to artificial sunlight irradiation. Mice exposed to aged PET showed increased airway resistance induced by methacholine inhalation, along with lung inflammation and neutrophil infiltration. Terephthalic acid (TPA) was continuously released from PET aged by artificial sunlight. Exposure to TPA also caused lung inflammation and enhanced airway resistance induced by methacholine (MCh) in mice. These findings indicate that aged PET can cause respiratory impairment via TPA release. A simple transport and degradation model was developed to quantitatively relate the abundance of aged PET produced in this study (ie, 4,000 × 96 W m-2 h) and aged fractions of PET that can be generated in the atmosphere. Our results suggested 10-60% of PET was degraded as that produced in this study over sunny regions in summer, whereas only lower than 1% in high-latitude cities in Europe in winter. This study demonstrates the importance of considering the abundance of aged PET and further development of a transport and degradation model of PET to assess the risk of degraded PET in the atmosphere.

Particulate Matter-Induced Emerging Health Effects Associated with Oxidative Stress and Inflammation

Environmental pollution continues to increase with industrial development and has become a threat to human health. Atmospheric particulate matter (PM) was designated as a Group 1 carcinogen by the International Agency for Research on Cancer in 2013 and is an emerging global environmental risk factor that is a major cause of death related to cardiovascular and respiratory diseases. PM is a complex composed of highly reactive organic matter, chemicals, and metal components, which mainly cause excessive production of reactive oxygen species (ROS) that can lead to DNA and cell damage, endoplasmic reticulum stress, inflammatory responses, atherosclerosis, and airway remodeling, contributing to an increased susceptibility to and the exacerbation of various diseases and infections. PM has various effects on human health depending on the particle size, physical and chemical characteristics, source, and exposure period. PM smaller than 5 μm can penetrate and accumulate in the alveoli and circulatory system, causing harmful effects on the respiratory system, cardiovascular system, skin, and brain. In this review, we describe the relationship and mechanism of ROS-mediated cell damage, oxidative stress, and inflammatory responses caused by PM and the health effects on major organs, as well as comprehensively discuss the harmfulness of PM.

Independent and joint associations between urinary polycyclic aromatic hydrocarbon metabolites and cognitive function in older adults in the United States

Background

Polycyclic aromatic hydrocarbons (PAHs), as organic pollutants widely present in daily environments, have been shown by existing epidemiological studies to be significantly associated with deficits in learning and memory functions in children and adults. However, the association between exposure to PAHs and cognitive function in older adults remains unclear. Additionally, existing related studies have only assessed the association between individual PAH exposures and cognitive assessments, overlooking the risks posed by mixed exposures. This study aims to use three statistical models to investigate the individual and overall effects of mixed PAH exposures on the cognition of older adults in the United States.

Methods

The study cohort was obtained from the NHANES database, which included individuals aged 60 and older from 2011 to 2014. Weighted generalized linear models (GLM), weighted quantile sum (WQS) models, and Bayesian kernel machine regression (BKMR) models were utilized to evaluate the connections between urinary PAH metabolites and the standardized Z-scores of four cognitive tests: Immediate Recall Test (IRT), Delayed Recall Test (DRT), Animal Fluency Test (AFT), and Digit Symbol Substitution Test (DSST).

Results

Our analysis involved 899 individuals aged 60 and above. In the fully adjusted GLM, 2-hydroxynaphthalene (2-OHNa), 3-hydroxyfluorene (3-OHFlu), and 2-hydroxyfluorene (2-OHFlu) demonstrated negative associations with DSST Z-scores. In the WQS model, six urinary PAH metabolites were negatively linked to AFT Z-scores (β (95% confidence intervals [CI]): -0.120 (-0.208, -0.033), p = 0.007) and DSST Z-scores (β (95% CI): -0.182 (-0.262, -0.103), p < 0.001). In both assessments, 2-OHNa exerted the greatest influence among the urinary PAH metabolites. In the BKMR model, there was an overall negative correlation between urinary PAH metabolites and AFT and DSST Z-scores when the concentration was within the 25th to 75th percentile, where 2-OHNa dominated the main effect of the mixture. The WQS and BKMR models were adjusted for all covariates.

Conclusion

Increased concentrations of urinary PAH metabolites are associated with cognitive decline in older adults, mainly on language ability, executive function, sustained attention, working memory, and information processing speed, with 2-OHNa playing a major effect.

Non-Linear Association Between Climatic Parameters and Bell's Palsy Prevalence of Hospital Outpatients: An Ecological Proof in Kunshan, Suzhou, China

Objective

This study aimed to explore the relationship between climatic parameters and the daily cases of Bell's palsy (BP) among hospital outpatients, providing ecological evidence for understanding BP etiology and prevention.

Methods

Retrospective analysis was conducted on data from 2187 BP patients who attended Kunshan First People's Hospital Outpatient Clinic from January 1, 2020, to December 31, 2022. Meteorological data, including temperature, relative humidity, precipitation, wind speed, sunshine duration, and atmospheric pressure, were collected and combined with daily BP case records. Additionally, air quality index was used as a covariate.

Results

The number of new BP cases among outpatients showed a negative correlation with average daily temperature. A nonlinear relationship between daily average temperature and BP cases was observed through the generalized additive model (GAM). A significant negative correlation was identified between daily average temperature and BP cases, with inflection points at temperatures above 4.2°C, suggesting a potential decrease in BP risk with temperature rise beyond this threshold.

Conclusion

This study provides ecological evidence of a link between climatic factors and BP occurrence. Temperature demonstrated a significant nonlinear negative correlation with daily BP incidence, highlighting temperature and cold exposure as key targets for BP prevention in Kunshan.

Decreases in the number of microglia and neural circuit dysfunction elicited by developmental exposure to neonicotinoid pesticides in mice

Neonicotinoids are insecticides widely used in the world. Although neonicotinoids are believed to be toxic only to insects, their developmental neurotoxicity in mammals is a concern. Therefore, we examined the effects of developmental exposure to neonicotinoids on immune system in the brain and post-developmental behaviors in this study. Imidacloprid or clothianidin was orally administered to dams at a dosage of 0.1 mg/kg/day from embryonic day 11 to postnatal day 21. Imidacloprid decreased sociability, and both imidacloprid and clothianidin decreased locomotor activity and induced anxiety, depression and abnormal repetitive behaviors after the developmental period. There was no change in the number of neurons in the hippocampus of mice exposed to imidacloprid. However, the number and activity of microglia during development were significantly decreased by imidacloprid exposure. Imidacloprid also induced neural circuit dysfunction in the CA1 and CA3 regions of the hippocampus during the early postnatal period. Exposure to imidacloprid suppressed the expression of csf1r during development. Collectively, these results suggest that developmental exposure to imidacloprid decreases the number and activity of microglia, which can cause neural circuit dysfunction and abnormal behaviors after the developmental period. Care must be taken to avoid exposure to neonicotinoids, especially during development.

Exposure to Environmental Toxins: Potential Implications for Stroke Risk via the Gut- and Lung-Brain Axis

Recent evidence indicates that exposure to environmental toxins, both short-term and long-term, can increase the risk of developing neurological disorders, including neurodegenerative diseases (i.e., Alzheimer's disease and other dementias) and acute brain injury (i.e., stroke). For stroke, the latest systematic analysis revealed that exposure to ambient particulate matter is the second most frequent stroke risk after high blood pressure. However, preclinical and clinical stroke investigations on the deleterious consequences of environmental pollutants are scarce. This review examines recent evidence of how environmental toxins, absorbed along the digestive tract or inhaled through the lungs, affect the host cellular response. We particularly address the consequences of environmental toxins on the immune response and the microbiome at the gut and lung barrier sites. Additionally, this review highlights findings showing the potential contribution of environmental toxins to an increased risk of stroke. A better understanding of the biological mechanisms underlying exposure to environmental toxins has the potential to mitigate stroke risk and other neurological disorders.

Independent and combined associations of polycyclic aromatic hydrocarbons exposure and sleep disorders among adults in the U.S. adult population

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are prevalent organic pollutants in the environment; however, limited research has been conducted to explore their potential effects on sleep disorders. This study aims to investigate the relationship between single and mixed PAHs exposures and sleep disorders.

METHODS

This study analyzed National Health and Nutrition Examination Survey (NHANES) data from 2005 to 2016, involving 7730 adult participants. To examine the relationship between PAHs exposure and sleep disorders, we employed survey-weighted multivariate logistic regression models and restricted cubic spline (RCS) models to evaluate single PAHs exposure. Additionally, we employed three mixed-exposure models to examine the relationship between combined PAHs exposure and sleep disorders.

RESULTS

After adjusting for covariates, our analyses revealed positive associations between several urinary PAHs metabolites (1-hydroxynaphthalene (1-NAP), 2-NAP, 3-hydroxyfluorene (3-FLU), 2-FLU, and 1-hydroxypyrene (1-PYR)) and sleep disturbance. Consistency across various analytical methods underscores a discernible positive correlation between simultaneous exposure to PAHs and sleep disorders. This association is predominantly influenced by the presence of NAP and FLU. Remarkably, a positive relationship between combined PAHs exposure and sleep disorders emerged within the younger and middle-aged demographic but did not manifest within the elderly population.

CONCLUSION

In conclusion, our study provides new epidemiological evidence suggesting that both single and mixed PAHs exposures may increase the risk of sleep disorders. Further prospective investigations are necessary to validate these findings.

Diabetes: a potential mediator of associations between polycyclic aromatic hydrocarbon exposure and stroke

Epidemiological evidence suggests associations between exposure to polycyclic aromatic hydrocarbons (PAHs) and cardiovascular diseases (CVD), while diabetes is a common risk factor for CVD. The present study aims to clarify the effect of high PAH exposure on diabetes and stroke in general population. A total of 7849 individuals aged 20 years or older from the National Health and Nutrition Examination Survey 2007-2016 were included in the study. The logistic regression analysis modeled the association between PAH exposure and diabetes as well as stroke. The analysis yielded odds ratios (ORs) and 95% confidence intervals (CIs). The study also evaluated the potential mediating role of diabetes in the relation between PAH exposure and stroke via mediating effect analyses. Of the 7849 eligible participants, 1424 cases of diabetes and 243 cases of stroke were recorded. After adjusting for covariates including age, gender, smoking status, drinking status, education level, marital status, physical activity, hypertension, low-density lipoprotein cholesterol, and BMI, the ORs for stroke in the highest quartile (Q4) of total urinary PAHs were 1.97 (95% CI 1.11-3.52, P = 0.022) as compared to the lowest quartile (Q1) of total urinary PAHs. The ORs for diabetes in the Q4 of total urinary PAHs were 1.56 (95% CI 1.15-2.12, P = 0.005), while the ORs between Q4 and Q1 for stroke and diabetes concerning exposure to 2-hydroxynaphthalene were 2.23 (95% CI 1.17-4.25, P = 0.016) and 1.40 (95% CI 1.07-1.82, P = 0.015), respectively. The mediation analysis found that diabetes accounted for 5.00% of the associations between urinary PAHs and the prevalence of stroke. Urinary metabolites of PAH have been linked to stroke and diabetes. Increasing the risk of diabetes may play a significant role in mediating the association between exposure to PAHs and increased risk of stroke. Monitoring and improving glucose metabolism in individuals with high exposure to PAHs may aid in reducing the prevalence of stroke.

A simple air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation

Particulate matter (PM) is among the major air pollutants suspended in the atmosphere. PM2.5 has a particle size of 2.5 µm; it is known to cause inflammation, especially in the respiratory tract and skin. Since the skin acts a primary barrier against harmful environmental substances that may enter the body, it is highly exposed to PM2.5 present in the environment. However, the adverse health effects of PM2.5 exposure on human skin have not been accurately examined due to the lack of a system that exposes human epidermal tissue to the actual environmental concentration of PM2.5. In this study, we developed an air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation. PM2.5 suspension was nebulized in an acrylic chamber, and the resulting mist was pumped through a diffusion dryer into a glass exposure chamber. A particle counter was connected to the exposure chamber to continuously measure the spatial mass concentration of PM. Human 3D epidermis was cultured in the exposure chamber. Exposure of the human 3D epidermis to PM aerosol increased interleukin-8 release into the media around 50 µg/m3. Mass concentrations above 100 µg/m3 caused cell death. Furthermore, a human corneal model showed similar responses against PM2.5 exposure as 3D epidermis. The air-liquid interface exposure system developed in this study is considered useful for evaluating the health effects induced by environmental PM2.5 and can be used as an alternative to experiments involving actual human or animals.

Astaxanthin alleviates PM2.5-induced cardiomyocyte injury via inhibiting ferroptosis

BACKGROUND

Long-term exposure of humans to air pollution is associated with an increasing risk of cardiovascular diseases (CVDs). Astaxanthin (AST), a naturally occurring red carotenoid pigment, was proved to have multiple health benefits. However, whether or not AST also exerts a protective effect on fine particulate matter (PM2.5)-induced cardiomyocyte damage and its underlying mechanisms remain unclear.

METHODS

In vitro experiments, the H9C2 cells were subjected to pretreatment with varying concentrations of AST, and then cardiomyocyte injury model induced by PM2.5 was established. The cell viability and the ferroptosis-related proteins expression were measured in different groups. In vivo experiments, the rats were pretreated with different concentrations of AST for 21 days. Subsequently, a rat model of myocardial PM2.5 injury was established by intratracheal instillation every other day for 1 week. The effects of AST on myocardial tissue injury caused by PM2.5 indicating by histological, serum, and protein analyses were examined.

RESULTS

AST significantly ameliorated PM2.5-induced myocardial tissue injury, inflammatory cell infiltration, the release of inflammatory factors, and cardiomyocyte H9C2 cell damage. Mechanistically, AST pretreatment increased the expression of SLC7A11, GPX4 and down-regulated the expression of TfR1, FTL and FTH1 in vitro and in vivo.

CONCLUSIONS

Our study suggest that ferroptosis plays a significant role in the pathogenesis of cardiomyocyte injury induced by PM2.5. AST may serve as a potential therapeutic agent for mitigating cardiomyocyte injury caused by PM2.5 through the inhibition of ferroptosis.

Exposure to polycyclic aromatic hydrocarbons (PAHs) in outdoor air and respiratory health, inflammation and oxidative stress biomarkers: A panel study in healthy young adults

Exposure to polycyclic aromatic hydrocarbons (PAHs) can be associated with different types of health effects. However, the systemic changes of health effects between fluctuations of PAHs exposure have not been established. In this study, urinary hydroxylated PAHs (OH-PAHs) and 12 biomarkers were determined among 36 students from the urban to the suburb in Taiyuan in 2019. The concentration of Σ12OH-PAHs in urban areas (28.2 and 21.4 μg/g Cr) was significantly higher than that in suburban area (16.8 μg/g Cr). The regression showed that hydroxy-phenanthrene (OH-Phe, 1/2/3/4/9-OH-Phe) was significantly positively correlated with lung function (PEF25 and PEF50), 8-hydroxydeoxyguanosine (8-OHdG), interleukin-8 (IL-8), and fractional exhaled nitric oxide (FeNO). Moreover, there were negative associations of 2-hydroxyfluorene (2-OH-Flu) with FVC and FEV1. 1 unit increase of 1-hydroxypyrene (1-OH-Pyr) was negatively associated with 18.8% FVC, 17.3% FEV1, and 26.4% PEF25 in the suburban location, respectively. During urban2, each unit change of 2-OH-Flu was associated with 10.9% FVC and 10.5% FEV1 decrease, which were higher than those in suburban location. 8-OHdG decreased by 32.0% with each unit increase in 3-hydroxyfluorene (3-OH-Flu) during urban2 (p < 0.05), while 1.9% in the suburban location. During the suburban period, the increase in OH-Phe was correlated with the decrease in malondialdehyde (MDA). The respiratory damage caused by PAHs in the urban disappeared after backing to the urban from the suburban area. Notably, despite the total significant liner mixed regression association of FeNO with multiple OH-PAHs, the association of FeNO with OH-PAHs was not significant during different periods except for 2-OH-Flu. Our findings suggested that short-term exposure to different concentrations of PAHs might cause changes in health effects and called for further research to investigate possible alterations between health effects and PAH exposure.

Polycyclic aromatic hydrocarbons and changes in brain cortical thickness and an Alzheimer's disease-specific marker for cortical atrophy in adults: A longitudinal neuroimaging study of the EPINEF cohort

Although several epidemiological studies have suggested that exposure to polycyclic aromatic hydrocarbons (PAHs) may induce brain atrophy, no longitudinal study has investigated the effect of PAH exposure on brain structural changes. This study examined the longitudinal associations between urinary PAH metabolites and brain cortical thickness. We obtained urinary concentrations of PAH metabolites and brain magnetic resonance images from 327 adults (≥50 years of age) without dementia at baseline and 3-year follow-up. We obtained whole-brain and regional cortical thicknesses, as well as an Alzheimer's disease (AD)-specific marker for cortical atrophy (a higher score indicated a greater similarity to patients with AD) at baseline and follow-up. We built a linear mixed-effect model including each of urinary PAH metabolites as the time-varying exposure variable of interest. We found that increases in urinary concentrations of 1-hydroxypyrene (β = -0.004; 95% CI, -0.008 to -0.001) and 2-hydroxyfluorene (β = -0.011; 95% CI, -0.015 to -0.006) were significantly associated with a reduced whole-brain cortical thickness. A urinary concentration of 2-hydroxyfluorene was significantly associated with an increased AD-specific cortical atrophy score (β = 2.031; 95% CI, 0.512 to 3.550). The specific brain regions showing the association of urinary concentrations of 1-hydroxypyrene, 2-naphthol, 1-hydroxyphenanthrene, or 2-hydroxyfluorene with cortical thinning were the frontal, parietal, temporal, and cingulate lobes. These findings suggested that exposure to PAHs may reduce brain cortical thickness and increase the similarity to AD-specific cortical atrophy patterns in adults.