Coarse particulate matter (PM2.5-10) in Los Angeles Basin air induces expression of inflammation and cancer biomarkers in rat brains

Research Progress on the Correlation Between Atmospheric Particulate Matter and Autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder caused by the interaction of genetic and complex environmental factors. The prevalence of autism has dramatically increased in countries and regions undergoing rapid industrialization and urbanization. Recent studies have shown that particulate matter (PM) in air pollution affects the development of neurons and disrupts the function of the nervous system, leading to behavioral and cognitive problems and increasing the risk of ASD. However, research on the mechanism of environmental factors and ASD is still in its infancy. On this basis, we conducted a literature search and analysis to review epidemiological studies on the correlation between fine particulate matter (PM2.5) and inhalable particulate matter (PM10) and ASD. The signaling pathways and pathogenic mechanisms of PM in synaptic injury and neuroinflammation are presented, and the mechanism of the ASD candidate gene SHANK3 was reviewed. Additionally, the different sites of action of different particles in animal models and humans were highlighted, and the differences of their effects on the pathogenesis of ASD were explained. We summarized the aetiology and mechanisms of PM-induced autism and look forward to future research breakthroughs in improved assessment methods, multidisciplinary alliances and high-tech innovations.

Air Pollution as an Environmental Risk Factor for Alzheimer's Disease and Related Dementias

Alzheimer's disease and related dementias are a leading cause of morbidity in our aging populations. Although influenced by genetic factors, fewer than 5% of Alzheimer's disease and related dementia cases are due solely to genetic causes. There is growing scientific consensus that these dementias arise from complex gene by environment interactions. The 2020 Lancet Commission on dementia prevention, intervention, and care identified 12 modifiable risk factors of dementia, including lifestyle, educational background, comorbidities, and environmental exposures to environmental contaminants. In this review, we summarize the current understanding and data gaps regarding the role(s) of environmental pollutants in the etiology of Alzheimer's disease and related dementias with a focus on air pollution. In addition to summarizing findings from epidemiological and experimental animal studies that link airborne exposures to environmental contaminants to increased risk and/or severity of Alzheimer's disease and related dementias, we discuss currently hypothesized mechanism(s) underlying these associations, including peripheral inflammation, neuroinflammation and epigenetic changes. Key data gaps in this rapidly expanding investigative field and approaches for addressing these gaps are also addressed.

Association between short- and medium-term exposure to air pollutants and depressive episode using comprehensive air quality index among the population in South Korea

BACKGROUND

Currently, air pollution is suggested as a risk factor for depressive episodes. Our study aimed to consider multiple air pollutants simultaneously, and continuously evaluate air pollutants using comprehensive air quality index (CAI) with depressive episode risk.

METHODS

Using a nationally representative sample survey from South Korea between 2014 and 2020, 20,796 participants who underwent health examination and Patient Depression Questionnaire-9 were included in the study. Six air pollutants (PM10, PM2.5, O3, CO, SO2, NO2) were measured for the analysis. Every air pollutant was standardized by air quality index (AQI) and CAI was calculated for universal representation. Using logistic regression, short- and medium-term exposure by AQI and CAI with the risk of depressive episode was calculated by odds ratio and 95 % confidence interval (CI). Furthermore, consecutive measurements of CAI over 1-month time intervals were evaluated with the risk of depressive episodes. Every analysis was conducted seasonally.

RESULTS

There were 950 depressive episodes occurred during the survey. An increase in AQI for short-term exposure (0-30 days) showed higher risk of depressive episode in CO, while medium-term exposure (0-120 days) showed higher risk of depressive episode in CO, SO2, PM2.5, and PM10. During the cold season, the exposure to at least one abnormal CAI within 1-month intervals over 120 days was associated with a 68 % (95 % CI 1.11-2.54) increase in the risk of depressive episode.

CONCLUSIONS

Short- and medium-term exposure of air pollution may be associated with an increased risk of depressive episodes, especially for cold season.

Influence of Cigarette Aerosol in Alpha-Synuclein Oligomerization and Cell Viability in SH-SY5Y: Implications for Parkinson's Disease

Although cigarette aerosol exposure is associated with various adverse health issues, its impact on Parkinson's disease (PD) remains elusive. Here, we investigated the effect of cigarette aerosol extract (CAE) on SH-SY5Y cells for the first time, both with and without α-synuclein (α-Syn) overexpression. We found that α-Syn aggravates CAE-induced cell death, oxidative stress, and mitochondrial dysfunction. Fluorescence cross-correlation spectroscopy (FCCS) revealed a dual distribution of α-Syn within the cells, with homogeneous regions indicative of monomeric α-Syn and punctated regions, suggesting the formation of oligomers. Moreover, we observed colocalization of α-Syn oligomers with lysosomes along with a reduction in autophagy activity. These findings suggest that α-Syn overexpression exacerbates CAE-induced intracellular cytotoxicity, mitochondrial dysfunction, and autophagy dysregulation, leading to elevated cell mortality. Our findings provide new insights into the pathogenic mechanisms linking exposure to cigarette aerosols with neurodegenerative diseases.

Association between air pollutant exposure, body water distribution and sleep disorder indices in individuals with low-arousal-threshold obstructive sleep apnoea

BACKGROUND

Air pollution may alter body water distribution, it may also be linked to low-arousal-threshold obstructive sleep apnoea (low-ArTH OSA). Here, we explored the mediation effects of air pollution on body water distribution and low-ArTH OSA manifestations.

METHODS

In this retrospective study, we obtained sleep centre data from healthy participants and patients with low-ArTH OSA (N=1924) in northern Taiwan. Air pollutant exposure at different time intervals (1, 3, 6 and 12 months) was estimated using the nearest station estimation method, and government air-quality data were also obtained. Regression models were used to assess the associations of estimated exposure, sleep disorder indices and body water distribution with the risk of low-ArTH OSA. Mediation analysis was performed to explore the relationships between air pollution, body water distribution and sleep disorder indices.

RESULTS

First, exposure to particulate matter (PM) with a diameter of ≤10 µm (PM10) for 1 and 3 months and exposure to PM with a diameter of ≤2.5 µm (PM2.5) for 3 months were significantly associated with the Apnoea-Hypopnoea Index (AHI), Oxygen Desaturation Index (ODI), Arousal Index (ArI) and intracellular-to-extracellular water ratio (I-E water ratio). Significant associations were observed between the risk of low-ArTH OSA and 1- month exposure to PM10 (OR 1.42, 95% CI 1.09 to 1.84), PM2.5 (OR 1.33, 95% CI 1.02 to 1.74) and ozone (OR 1.27, 95% CI 1.01 to 1.6). I-E water ratio alternation caused by 1-month exposure to PM10 and 3-month exposure to PM2.5 and PM10 had partial mediation effects on AHI and ODI.

CONCLUSION

Air pollution can directly increase sleep disorder indices (AHI, ODI and ArI) and alter body water distribution, thus mediating the risk of low-ArTH OSA.

Exposure to environmental airborne particulate matter caused wide-ranged transcriptional changes and accelerated Alzheimer's-related pathology: A mouse study

Air pollution poses a significant threat to human health, though a clear understanding of its mechanism remains elusive. In this study, we sought to better understand the effects of various sized particulate matter from polluted air on Alzheimer's disease (AD) development using an AD mouse model. We exposed transgenic Alzheimer's mice in their prodromic stage to different sized particulate matter (PM), with filtered clean air as control. After 3 or 6 months of exposure, mouse brains were harvested and analyzed. RNA-seq analysis showed that various PM have differential effects on the brain transcriptome, and these effects seemed to correlate with PM size. Many genes and pathways were affected after PM exposure. Among them, we found a strong activation in mRNA Nonsense Mediated Decay pathway, an inhibition in pathways related to transcription, neurogenesis and survival signaling as well as angiogenesis, and a dramatic downregulation of collagens. Although we did not detect any extracellular Aβ plaques, immunostaining revealed that both intracellular Aβ1-42 and phospho-Tau levels were increased in various PM exposure conditions compared to the clean air control. NanoString GeoMx analysis demonstrated a remarkable activation of immune responses in the PM exposed mouse brain. Surprisingly, our data also indicated a strong activation of various tumor suppressors including RB1, CDKN1A/p21 and CDKN2A/p16. Collectively, our data demonstrated that exposure to airborne PM caused a profound transcriptional dysregulation and accelerated Alzheimer's-related pathology.

The connection between six common air pollution particles and adult brain tumors: a meta-analysis of 26,217,930 individuals

Environmental air pollutants (black carbon (BC), nitrogen oxides (NOx), particulate matter with diameter < 2.5 μm (PM2.5), nitrogen dioxide (NO2), particulate matter with diameter <10 μm (PM10), and ozone (O3)) are one of the major menaces to mankind's health globally. This analysis reviews the association between exposure to these air pollutants and the chance of developing brain tumors in adults (total brain tumors, malignant brain tumors, and benign brain tumors). Studies published by April 2022 were searched. Raw effect sizes were converted to standardized effect sizes per 10 μg/m3 increase. Random effect models were applied to calculate combined effect size and 95% confidence intervals (CIs) were computed. A total of 8 articles were included for meta-analysis. The pooled effect size (ES) for per 10 μg/m3 BC intake was 1.67 (95% CI: 1.25, 2.22), P = 0.449. For every 10 μg/m3 rise in NO2 concentration, ES was 1.03 (95% CI: 1.01, 1.05), P = 0.319. Meanwhile, there was a boundary association between NOx and adult brain tumors (ES and 95% CI: 1.01; 1.00, 1.01/10 μg/m3; P = 0.716). While there was no conjunction between PM2.5, PM10, O3 (PM2.5: ES and 95% CI: 1.04; 0.99, 1.08/10 μg/m3; P = 0.834; PM10: ES and 95% CI: 1.01; 0.97, 1.04/10 μg/m3; P = 0.627; O3: ES and 95% CI: 0.97; 0.94, 1.00/10 μg/m3; P = 0.253). This research shows testimony of a significant link between air pollutants and brain tumors in adults, especially when exposed to BC, NO2, and NOx. This evidence emphasizes the importance of improving air quality as part of a comprehensive approach to prevent the occurrence and deterioration of brain tumors.

Particulate matter, traffic-related air pollutants, and circulating C-reactive protein levels: The Multiethnic Cohort Study

Inhaled particles and gases can harm health by promoting chronic inflammation in the body. Few studies have investigated the relationship between outdoor air pollution and inflammation by race and ethnicity, socioeconomic status, and lifestyle risk factors. We examined associations of particulate matter (PM) and other markers of traffic-related air pollution with circulating levels of C-reactive protein (CRP), a biomarker of systemic inflammation. CRP was measured from blood samples obtained in 1994-2016 from 7,860 California residents participating in the Multiethnic Cohort (MEC) Study. Exposure to PM (aerodynamic diameter ≤2.5 μm [PM2.5], ≤10 μm [PM10], and between 2.5 and 10 μm [PM10-2.5]), nitrogen oxides (NOx, including nitrogen dioxide [NO2]), carbon monoxide (CO), ground-level ozone (O3), and benzene averaged over one or twelve months before blood draw were estimated based on participants' addresses. Percent change in geometric mean CRP levels and 95% confidence intervals (CI) per standard concentration increase of each pollutant were estimated using multivariable generalized linear regression. Among 4,305 females (55%) and 3,555 males (45%) (mean age 68.1 [SD 7.5] years at blood draw), CRP levels increased with 12-month exposure to PM10 (11.0%, 95% CI: 4.2%, 18.2% per 10 μg/m3), PM10-2.5 (12.4%, 95% CI: 1.4%, 24.5% per 10 μg/m3), NOx (10.4%, 95% CI: 2.2%, 19.2% per 50 ppb), and benzene (2.9%, 95% CI: 1.1%, 4.6% per 1 ppb). In subgroup analyses, these associations were observed in Latino participants, those who lived in low socioeconomic neighborhoods, overweight or obese participants, and never or former smokers. No consistent patterns were found for 1-month pollutant exposures. This investigation identified associations of primarily traffic-related air pollutants, including PM, NOx, and benzene, with CRP in a multiethnic population. The diversity of the MEC across demographic, socioeconomic, and lifestyle factors allowed us to explore the generalizability of the effects of air pollution on inflammation across subgroups.

Korean Red Ginseng Prevents the Deterioration of Lung and Brain Function in Chronic PM2.5-Exposed Mice by Regulating Systemic Inflammation

This study was conducted to confirm the effects of Korean red ginseng on lung and brain dysfunction in a BALB/c mice model exposed to particulate matter (PM)2.5 for 12 weeks. Learning and cognitive abilities were assessed with Y-maze, passive avoidance, and Morris water maze tests. To evaluate the ameliorating effect of red ginseng extract (RGE), the antioxidant system and mitochondrial function were investigated. The administration of RGE protected lung and brain impairment by regulating the antioxidant system and mitochondrial functions damaged by PM2.5-induced toxicity. Moreover, RGE prevented pulmonary fibrosis by regulating the transforming growth factor beta 1 (TGF-β1) pathway. RGE attenuated PM2.5-induced pulmonary and cognitive dysfunction by regulating systemic inflammation and apoptosis via the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)/c-Jun N-terminal kinases (JNK) pathway. In conclusion, RGE might be a potential material that can regulate chronic PM2.5-induced lung and brain cognitive dysfunction.

Association of long-term exposure to ambient air pollution with retinal neurodegeneration: The prospective alienor study

Chronic exposure to air pollution may have adverse effects on neurodegenerative diseases. Glaucoma, the second leading cause of blindness worldwide, is a neurodegenerative disease of the optic nerve, characterized by progressive thinning of the retinal nerve fiber layer (RNFL). We investigated the relationship of air pollution exposure with longitudinal changes of RNFL thickness in the Alienor study, a population-based cohort of residents of Bordeaux, France, aged 75 years or more. Peripapillary RNFL thickness was measured using optical coherence tomography imaging every 2 years from 2009 to 2020. Measurements were acquired and reviewed by specially trained technicians to control quality. Air pollution exposure (particulate matter ≤2.5 μm (PM_2.5), black carbon (BC), nitrogen dioxide (NO₂)) was estimated at the participants' geocoded residential address using land-use regression models. For each pollutant, the 10-year average of past exposure at first RNFL thickness measurement was estimated. Associations of air pollution exposure with RNFL thickness longitudinal changes were assessed using linear mixed models adjusted for potential confounders, allowing for intra-eye and intra-individual correlation (repeated measurements). The study included 683 participants with at least one RNFL thickness measurement (62% female, mean age 82 years). The average RNFL was 90 μm (SD:14.4) at baseline. Exposure to higher levels of PM_2.5 and BC in the previous 10 years was significantly associated with a faster RNFL thinning during the 11-year follow-up (-0.28 μm/year (95% confidence interval (CI) [-0.44;-0.13]) and -0.26 μm/year (95% CI [-0.40;-0.12]) per interquartile range increment; p < 0.001 for both). The size of the effect was similar to one year of age in the fitted model (-0.36 μm/year). No statistically significant associations were found with NO₂ in the main models. This study evidenced a strong association of chronic exposure to fine particulate matter with retinal neurodegeneration, at air pollution levels below the current recommended thresholds in Europe.

Impacts of Environmental Pollution on Brain Tumorigenesis

Pollutants consist of several components, known as direct or indirect mutagens, that can be associated with the risk of tumorigenesis. The increased incidence of brain tumors, observed more frequently in industrialized countries, has generated a deeper interest in examining different pollutants that could be found in food, air, or water supply. These compounds, due to their chemical nature, alter the activity of biological molecules naturally found in the body. The bioaccumulation leads to harmful effects for humans, increasing the risk of the onset of several pathologies, including cancer. Environmental components often combine with other risk factors, such as the individual genetic component, which increases the chance of developing cancer. The objective of this review is to discuss the impact of environmental carcinogens on modulating the risk of brain tumorigenesis, focusing our attention on certain categories of pollutants and their sources.

Long-term air pollution and risk of amyotrophic lateral sclerosis mortality in the Women's Health Initiative cohort

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder with no cure. Although the etiology of sporadic ALS is largely unknown, environmental exposures may affect ALS risk.

OBJECTIVE

We investigated relationships between exposure to long-term ambient particulate matter (PM) and gaseous air pollution (AP) and ALS mortality.

METHODS

Within the Women's Health Initiative (WHI) cohort of 161,808 postmenopausal women aged 50-79 years at baseline (1993-1998), we performed a nested case-control study of 256 ALS deaths and 2486 matched controls with emphasis on PM constituents (PM_2.5, PM₁₀, and coarse PM [PM₁₀-_2.5]) and gaseous pollutants (NO_x, NO₂, SO₂, and ozone). Time-varying AP exposures estimates were averaged 5, 7.5, and 10 years prior to ALS death using both a GIS-based spatiotemporal generalized additive mixed model and ordinary kriging (empirical and multiple imputation, MI). Conditional logistic regression was used to estimate the relative risk of ALS death.

RESULTS

In general, PM_2.5 and PM₁₀-related risks were not significantly elevated using either method. However, for PM_10-2.5, odds ratios (ORs) were >1.0 for both methods at all time periods using MI and empirical data for PM_10-2.5 (coarse) except for 5 and 7.5 years using the kriging method with covariate adjustment.

CONCLUSION

This investigation adds to the body of information on long-term ambient AP exposure and ALS mortality. Specifically, the 2019 US Environmental Protection Agency (EPA) Integrated Science Assessment summarized the neurotoxic effects of PM_2.5, PM_10, and PM₁₀-_2.5. The conclusion was that evidence of an effect of coarse PM is suggestive but the data is presently not sufficient to infer a causal relationship. Further research on AP and ALS is warranted. As time from symptom onset to death in ALS is ∼2-4 years, earlier AP measures may also be of interest to ALS development. This is the first study of ALS and AP in postmenopausal women controlling for individual-level confounders.

Investigation of organic carbon profiles and sources of coarse PM in Los Angeles

Source apportionment analyses are essential tools to determine sources of ambient coarse particles (2.5 <d_p < 10 μm) and to disentangle their association and contribution from other pollutants, particularly PM_2.5 (<2.5 μm). A semi-continuous sampling campaign was conducted using two virtual impactors/concentrators to enhance coarse particulate matter concentrations coupled with an online thermal-optical EC/OC monitor to quantify coarse PM-bound organic carbon volatility fractions (OC₁-OC₄) in central Los Angeles during the winter, spring, and summer of 2021. The total OC and its volatility fraction concentrations, meteorological parameters (i.e., wind speeds and relative humidity), vehicle miles traveled (VMT), and gaseous source tracers (i.e., O₃ and NO₂) were used as inputs to positive matrix factorization (PMF) model. A 3-factor solution identified vehicular emissions (accounting for 46% in the cold phase and 26% in the warm phase of total coarse OC concentrations), secondary organic carbon (27% and 37%), and re-suspended dust (27% and 37%) as the primary organic carbon sources of coarse PM. The re-suspended dust factor showed a higher contribution of more volatile organic carbons (i.e., OC₁ up to 77%) due to their re-distribution on dust particles, whereas the SOA factor was the dominant contributor to less volatile organic aerosols (i.e., OC₄ up to 54%), which are the product of reactions at high relative humidity (RH). Our findings revealed that the total OC concentrations in the coarse size range were comparable with those of previous studies in the area, underscoring the challenges in curtailing coarse PM-bound OC sources and the necessity of developing effective emission control regulations on coarse PM. The results from the current study provide insights into the seasonal and temporal variation of total OC and its volatility fractions in Los Angeles.

The Association between Exposure to Air Pollution and Type 1 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Background

This systematic review and meta-analysis aimed to overview the observational studies on the association of exposure to air pollution and type 1 diabetes mellitus (T1DM).

Materials and Methods

Based on PRISMA guidelines, we systematically reviewed the databases of PubMed, Scopus, Embase, and Web of Science databases to determine the association of air pollution exposure and T1DM. Quality assessment of the papers was evaluated using the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) checklist for observational studies. The odds ratios (OR) and their 95% confidence intervals (CI) were calculated to assess the strength of the associations between air pollutants (gases and particulate matter air pollutants including PM10, PM2.5, NO2, volatile organic compound, SO4, SO2, O3) and T1DM.

Results

Out of 385 initially identified papers, 6 studies were used for this meta-analysis. Fixed effects meta-analysis showed a significant association between per 10 μg/m³ increase in O3 and PM2.5 exposures with the increased risk of T1DM (3 studies, OR = 1.51, 95% CI: 1.26, 1.80, I ² = 83.5% for O3 and two studies, OR = 1.03, 95% CI: 1.01, 1.05, I ² = 76.3% for PM2.5). There was no evidence of association between increased risk of T1DM and exposure to PM10 (OR = 1.02, 95% CI: 0.99-1.06, I ² = 59.4%), SO4 (OR = 1.16, 95% CI: 0.91-1.49, I ² = 93.8%), SO2 (OR = 0.94, 95% CI: 0.83-1.06, I ² = 85.0%), and NO2 (OR = 0.995,95% CI: 1.05-1.04, I ² = 24.7%).

Conclusion

Recent publications indicated that exposure to ozone and PM2.5 may be a risk factor for T1DM. However, due to limited available studies, more prospective cohort studies are needed to clarify the role of air pollutants in T1DM occurrence.

Particulate Matters Affecting lncRNA Dysregulation and Glioblastoma Invasiveness: In Silico Applications and Current Insights

With a reported rise in global air pollution, more than 50% of the population remains exposed to toxic air pollutants in the form of particulate matters (PMs). PMs, from various sources and of varying sizes, have a significant impact on health as long-time exposure to them has seen a correlation with various health hazards and have also been determined to be carcinogenic. In addition to disrupting known cellular pathways, PMs have also been associated with lncRNA dysregulation-a factor that increases predisposition towards the onset or progression of cancer. lncRNA dysregulation is further seen to mediate glioblastoma multiforme (GBM) progression. The vast array of information regarding cancer types including GBM and its various precursors can easily be obtained via innovative in silico approaches in the form of databases such as GEO and TCGA; however, a need to obtain selective and specific information correlating anthropogenic factors and disease progression-in the case of GBM-can serve as a critical tool to filter down and target specific PMs and lncRNAs responsible for regulating key cancer hallmarks in glioblastoma. The current review article proposes an in silico approach in the form of a database that reviews current updates on correlation of PMs with lncRNA dysregulation leading to GBM progression.

Toxic Air Pollutants and Their Effect on Multiple Sclerosis: A Review Study

Toxic air pollutants are one of the main factors that have the effect of synergism to increase the incidence of multiple sclerosis (MS). This review aims to investigate the effects of toxic air pollutants on the occurrence of multiple sclerosis (MS). A narrative review of the literature was done from 2000 to 2022 based on various databases such as Google Scholar, Web of Science, Springer, PubMed, and Science Direct. In this study, according to the databases, three hundred and sixty articles were retrieved. Of these, 28 studies were screened after review and 14 full-text articles entered into the analysis process. Finally, 9 articles were selected in this study. According to the finding of this study, toxic air pollutants including polycyclic aromatic hydrocarbons (PAHs), heavy metals (HM), volatile organic compounds (VOCs), particulate matter (PM), and gases are the main agents that cause the development and spread of chronic diseases such as respiratory and cardiovascular diseases, chronic obstructive pulmonary disease (COPD), and multiple sclerosis. The result of this study showed that the main sources of emission of toxic air pollutants include industries, cars, power plants, and the excessive consumption of fossil fuels. In general, the inhalation of high concentration of toxic air pollutants can increase the risk of chronic diseases and multiple sclerosis.

Particulate Matter Exacerbates the Death of Dopaminergic Neurons in Parkinson's Disease through an Inflammatory Response

Particulate matter (PM), a component of air pollution, has been epidemiologically associated with a variety of diseases. Recent reports reveal that PM has detrimental effects on the brain. In this study, we aimed to investigate the biological effects of ambient particles on the neurodegenerative disease Parkinson’s disease (PD). We exposed mice to coarse particles (PM₁₀: 2.5–10 μm) for short (5 days) and long (8 weeks) durations via intratracheal instillation. Long-term PM₁₀ exposure exacerbated motor impairment and dopaminergic neuron death in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mouse models. Short-term PM₁₀ exposure resulted in both pulmonary and systemic inflammatory responses in mice. We further investigated the mechanism underlying PM₁₀-induced neurotoxicity in cocultures of lung LA-4 epithelial cells and RAW264.7 macrophages. PM₁₀ treatment elicited a dramatic increase in proinflammatory mediators in LA-4/RAW264.7 coculture. Treating BV2 microglial cells with PM₁₀-treated conditioned medium induced microglial activation. Furthermore, 1-methyl-4-phenylpyridinium (MPP⁺) treatment caused notable cell death in N2A neurons cocultured with activated BV2 cells in PM₁₀-conditioned medium. Altogether, our results demonstrated that PM₁₀ plays a role in the neurodegeneration associated with PD. Thus, the impact of PM₁₀ on neurodegeneration could be related to detrimental air pollution-induced systemic effects on the brain.

Neurosurgery at the crossroads of immunology and nanotechnology. New reality in the COVID-19 pandemic

Neurosurgery as one of the most technologically demanding medical fields rapidly adapts the newest developments from multiple scientific disciplines for treating brain tumors. Despite half a century of clinical trials, survival for brain primary tumors such as glioblastoma (GBM), the most common primary brain cancer, or rare ones including primary central nervous system lymphoma (PCNSL), is dismal. Cancer therapy and research have currently shifted toward targeted approaches, and personalized therapies. The orchestration of novel and effective blood-brain barrier (BBB) drug delivery approaches, targeting of cancer cells and regulating tumor microenvironment including the immune system are the key themes of this review. As the global pandemic due to SARS-CoV-2 virus continues, neurosurgery and neuro-oncology must wrestle with the issues related to treatment-related immune dysfunction. The selection of chemotherapeutic treatments, even rare cases of hypersensitivity reactions (HSRs) that occur among immunocompromised people, and number of vaccinations they have to get are emerging as a new chapter for modern Nano neurosurgery.

A critical review of environmentally persistent free radical (EPFR) solvent extraction methodology and retrieval efficiency

Long-lived environmentally persistent free radical (EPFR) exposures have been shown in toxicology studies to lead to respiratory and cardiovascular effects, which were thought to be due to the persistence of EPFR and their ability to produce reactive oxygen species. To characterize EPFR exposure and resulting health impacts, it is necessary to identify and systematize analysis protocols. Both direct measurement and solvent extraction methods have been applied to analyze environmental samples containing EPFR. The use of different protocols and solvents in EPFR analyses makes it difficult to compare results among studies. In this work, we reviewed EPFR studies that involved solvent extraction and carefully reported the details of the extraction methodology and retrieval recovery. EPFR recovery depends on the structure of the radical species and the solvent. For the limited number of studies available for review, the polar solvents had superior recovery in more studies. Radicals appeared to be more oxygen-centered following extraction for fly ash and particulate matter (PM) samples. Different solvent extraction methods to retrieve EPFR may produce molecular products during the extraction, thus potentially changing the sample toxicity. The number of studies reporting detailed methodologies is limited, and data in these studies were not consistently reported. Thus, inference about the solvent and protocol that leads to the highest EPFR extraction efficiency for certain types of radicals is not currently possible. Based on our review, we proposed reporting criteria to be included for future EPFR studies.

Mitochondria damage in ambient particulate matter induced cardiotoxicity: Roles of PPAR alpha/PGC-1 alpha signaling

Particulate matter (PM) had been associated with cardiotoxicity, while the mechanism of toxicity has yet to be elucidated, with mitochondria dysfunction as a potential candidate. To investigate the potential cardiotoxic effects of ambient PM exposure and assess the damage to cardiac mitochondria, C57/B6 mice were exposed to filtered air or real ambient PM for three or six weeks. Furthermore, to reveal the role of peroxisome proliferators-activated receptor alpha (PPAR alpha) in PM exposure induced cardiotoxicity/mitochondria damage, animals were also co-treated with PPAR alpha agonist WY 14,643 or PPAR alpha antagonist GW 6471. Cardiotoxicity was assessed with echocardiography and histopathology, while mitochondria damage was evaluated with mitochondria membrane potential measurement and transmission electron microscopy. Potential impacts of PM exposure to PPAR alpha signaling were detected with co-immunoprecipitation and western blotting. The results indicated that exposure to ambient PM exposure induced cardiotoxicity in C57/B6 mice, including altered cardiac functional parameters and morphology. Cardiac mitochondria damage is detected, in the form of compromised mitochondria membrane potential and morphology. Molecular investigations revealed disruption of PPAR alpha interaction with peroxisome proliferator-activated receptor gamma coactivator-1A (PGC-1a) as well as altered expression levels of PPAR alpha downstream genes. Co-treatment with WY 14,643 alleviated the observed toxicities, while co-treatment with GW 6471 had mixed results, exaggerating most cardiotoxicity and mitochondrial damage endpoints but alleviating some cardiac functional parameters. Interestingly, WY 14,643 and GW 6471 co-treatment seemed to exhibit similar regulative effects towards PPAR alpha signaling in animals exposed to PM. In conclusion, ambient PM exposure indeed induced cardiotoxicity in C57/B6 mice, in which cardiac mitochondria damage and disrupted PPAR alpha signaling are contributors.

Association of short-term exposure to air pollution with depression in patients with sleep-related breathing disorders

Air pollution is associated with sleep-related breathing disorders; however, the effects of air pollution on depression in patients with SRBDs remain unclear. A cross-sectional study was conducted to collect polysomnographic (PSG) data and Beck Depression Inventory-IA (BDI-IA) responses from 568 subjects with SRDBs in a sleep center in 2015 to 2017. Exposure to air pollution, including particulate matter with an aerodynamic diameter of ≤10 μm (PM₁₀), particulate matter with an aerodynamic diameter of ≤2.5 μm (PM_2.5), nitrogen (NO₂), sulfur dioxide (SO₂), carbon monoxide (CO) and ozone (O₃), in 1-month averages was collected. Associations of air pollution with the respiratory disturbance index (RDI), oxygen desaturation index (ODI), arousal index (ARI), sleep architecture, and BDI-IA were examined. We observed that interquartile range (IQR) increases in 1-month PM_2.5, PM₁₀, and NO₂ levels were respectively associated with 4.1/hour (h) (95% confidence interval (CI): 1.7/h to 6.4/h), 3.7/h (95% CI: 1.4/h to 6.0/h) and 1.9/h (95% CI: 0.1/h to 3.7/h) increases in the ARI. For sleep architecture, IQR increases in 1-month PM_2.5 and CO levels were respectively associated with a 6.2% (95% CI: 6.1% to 6.3%) increase in non-rapid eye movement sleep 1 (N1) and a 2.0% (95% CI: -3.8% to -0.1%) decrease in non-rapid eye movement sleep 2 (N2). For depression, an IQR change in the 1-month CO was associated a moderate/severe depressive status according to the BDI-IA (odds ratio, OR: 2.981, p < 0.05; 95% CI: 1.032 to 8.611). Short-term exposure to air pollution increased the risk of arousal and light sleep as well as depression in patients with SRBDs. The results suggest that SRBD patients could be a population at risk for depression due to short-term exposure to air pollution.

Exposure to low-dose ambient fine particulate matter PM2.5 and Alzheimer's disease, non-Alzheimer's dementia, and Parkinson's disease in North Carolina

Alzheimer's disease (AD), non-AD dementia, and Parkinson's disease (PD) are increasingly common in older adults, yet all risk factors for their onset are not fully understood. Consequently, environmental exposures, including air pollution, have been hypothesized to contribute to the etiology of neurodegeneration. Because persistently elevated rates of AD mortality in the southern Piedmont area of North Carolina (NC) have been documented, we studied mortality and hospital admissions for AD, non-AD dementia, and PD in residential populations aged 65+ with long-term exposures to elevated levels of ambient air particulate matter 2.5 (PM2.5) exceeding the World Health Organization (WHO) air quality standards (≥10μg/m3). Health data were obtained from the State Center for Health Statistics and the Healthcare Cost and Utilization Project. PM2.5 levels were obtained from the MODIS/MISR and SeaWiFS datafiles. Residents in the Study group of elevated air particulate matter (87 zip codes with PM2.5≥10μg/m3) were compared to the residents in the Control group with low levels of air particulate matter (81 zip codes with PM2.5≤7.61μg/m3), and were found to have higher age-adjusted rates of mortality and hospital admissions for AD, non-AD dementia, and PD, including a most pronounced increase in AD mortality (323/100,000 vs. 257/100,000, respectively). After adjustment for multiple co-factors, the risk of death (odds ratio, or OR) from AD in the Study group (OR = 1.35, 95%CI[1.24-1.48]) was significantly higher than ORs of non-AD dementia or PD (OR = 0.97, 95%CI[0.90-1.04] and OR = 1.13, 95%CI[0.92-1.31]). The OR of hospital admissions was significantly increased only for AD as a primary case of hospitalization (OR = 1.54, 95%CI[1.31-1.82]). Conclusion: NC residents aged 65+ with long-term exposures to ambient PM2.5 levels exceeding the WHO standard had significantly increased risks of death and hospital admissions for AD. The effects for non-AD dementia and PD were less pronounced.

PM2.5 as a potential risk factor for autism spectrum disorder: Its possible link to neuroinflammation, oxidative stress and changes in gene expression

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by behavioral deficits including impairments in social communication, social interaction, and repetitive behaviors. Because the etiology of ASD is still largely unknown, there is no cure for ASD thus far. Although it has been established that genetic components play a vital role in ASD development, the influence of epigenetic regulation induced by environmental factors could also contribute to ASD susceptibility. Accumulated evidence has suggested that exposure to atmospheric particulate matter (PM) in polluted air could affect neurodevelopment, thus possibly leading to ASD. Particles with a size of 2.5 μm (PM_2.5) or less have been shown to have negative effects on human health, and could be linked to ASD symptoms in children. This review summarizes evidence from clinical and animal studies to demonstrate the possible linkage between PM_2.5 exposure and the incidence of ASD in children. An attempt was made to explore the possible mechanisms of this linkage, including changes of gene expression, oxidative stress and neuroinflammation induced by PM_2.5 exposure.

Biological effect of PM10 on airway epithelium-focus on obstructive lung diseases

Recently, a continuous increase in environmental pollution has been observed. Despite wide-scale efforts to reduce air pollutant emissions, the problem is still relevant. Exposure to elevated levels of airborne particles increased the incidence of respiratory diseases. PM₁₀ constitute the largest fraction of air pollutants, containing particles with a diameter of less than 10 μm, metals, pollens, mineral dust and remnant material from anthropogenic activity. The natural airway defensive mechanisms against inhaled material, such as mucus layer, ciliary clearance and macrophage phagocytic activity, may be insufficient for proper respiratory function. The epithelium layer can be disrupted by ongoing oxidative stress and inflammatory processes induced by exposure to large amounts of inhaled particles as well as promote the development and exacerbation of obstructive lung diseases. This review draws attention to the current state of knowledge about the physical features of PM₁₀ and its impact on airway epithelial cells, and obstructive pulmonary diseases.

The association between ozone and fine particles and mental health-related emergency department visits in California, 2005-2013

Recent studies suggest that air pollutant exposure may increase the incidence of mental health conditions, however research is limited. We examined the association between ozone (O3) and fine particles (PM2.5) and emergency department (ED) visits related to mental health outcomes, including psychosis, neurosis, neurotic/stress, substance use, mood/affective, depression, bipolar, schizotypal/delusional, schizophrenia, self-harm/suicide, and homicide/inflicted injury, from 2005 through 2013 in California. Air monitoring data were provided by the U.S. EPA's Air Quality System Data Mart and ED data were provided by the California Office of Statewide Health Planning and Development. We used the time-series method with a quasi-Poisson regression, controlling for apparent temperature, day of the week, holidays, and seasonal/long-term trends. Per 10 parts per billion increase, we observed significant cumulative 7-day associations between O3 and all mental health [0.64%, 95% confidence interval (CI): 0.21, 1.07], depression [1.87%, 95% CI: 0.62, 3.15], self-harm/suicide [1.43%, 95% CI: 0.35, 2.51], and bipolar [2.83%, 95% CI: 1.53, 4.15]. We observed 30-day lag associations between O3 and neurotic disorder [1.22%, 95% CI: 0.48, 1.97] and homicide/inflicted injury [2.01%, 95% CI: 1.00, 3.02]. Same-day mean PM2.5 was associated with a 0.42% [95% CI: 0.14, 0.70] increase in all mental health, 1.15% [95% CI: 0.62, 1.69] increase in homicide/inflicted injury, and a 0.57% [95% CI: 0.22, 0.92] increase in neurotic disorders per 10 μg/m3 increase. Other outcomes not listed here were not statistically significant for O3 or PM2.5. Risk varied by age group and was generally greater for females, Asians, and Hispanics. We also observed seasonal variation for outcomes including but not limited to depression, bipolar, schizophrenia, self-harm/suicide, and homicide/inflicted injury. Ambient O3 or PM2.5 may increase the risk of mental health illness, though underlying biological mechanisms remain poorly understood. Findings warrant further investigation to better understand the impacts of air pollutant exposure among vulnerable groups.

Distribution of toxic metals and relative toxicity of airborne PM2.5 in Puerto Rico

The exposure to airborne particulate matter (PM) and its constituents is an important factor to be considered when evaluating their potential health risk. Transition metals found in PM are known to contribute significantly to the exacerbation of respiratory ailments. Exposure to these constituents results in the induction of oxidative stress in the bronchial epithelium, thus promoting the secretion of inflammatory mediators. Therefore, it is important to know the contributions of PM2.5 constituents to further investigate their relationship with toxic responses and associated health risks. PM2.5 samples from three rural (Humacao, Guayama, and Guayanilla) and two urban (more populated) sites (Bayamón and Ponce) from Puerto Rico were analyzed for various inorganic constituents. A total of 59 trace elements were analyzed, of which eight were considered with the greatest toxic potential. The highest annual average concentration of PM2.5 was reported at the urban site of Ponce (5.82 ± 1.40 μg m-3), while Bayamón's average concentration was not as high (4.69 ± 1.30 μg m-3) compared to concentrations at the rural sites Humacao, Guayama, and Guayanilla (4.33 ± 1.20 μg m-3, 4.93 ± 1.50 μg m-3, and 4.88 ± 1.20 μg m-3 respectively. The concentration at the Ponce site exhibited the highest summer value (7.57 μg m-3) compared to that of all the rural sites (~ 6.40 μg m-3). The lowest summer PM2.5 values were obtained at the Humacao site with an average of 5.76 μg m-3. Average Cu and Zn concentrations were 3- and 2-fold higher at the urban sites (0.68 ng m-3 and 6.74 ng m-3 respectively) compared to the rural sites (0.17 ng m-3 and 4.11 ng m-3). Relative toxicity of inorganic PM extract indicates Bayamón (urban) and Guayama with similar low LC50 followed by Humacao, Guayanilla, and finally Ponce (urban) with the highest LC50. Of the eight potential toxic metals considered, only Fe was found to be higher at the rural sites. To our understanding, there are different sources of emission for these metals which potentially indicate main anthropogenic sources, together with the trade winds adding periodically volcanic and African Dust Storm particulates that affect Puerto Rico. These results are the first of their kind to be reported in Puerto Rico.

Inflammatory effects of particulate matter air pollution

Air pollution is an important cause of non-communicable diseases globally with particulate matter (PM) as one of the main air pollutants. PM is composed of microscopic particles that contain a mixture of chemicals and biological elements that can be harmful to human health. The aerodynamic diameter of PM facilitates their deposition when inhaled. For instance, coarse PM having a diameter of < 10 μm is deposited mainly in the large conducting airways, but PM of < 2.5 μm can cross the alveolar-capillary barrier, traveling to other organs within the body. Epidemiological studies have shown the association between PM exposure and risk of disease, namely those of the respiratory system such as lung cancer, asthma, and chronic obstructive pulmonary disease (COPD). However, cardiovascular and neurological diseases have also been reported, including hypertension, atherosclerosis, acute myocardial infarction, stroke, loss of cognitive function, anxiety, and Parkinson's and Alzheimer's diseases. Inflammation is a common hallmark in the pathogenesis of many of these diseases associated with exposure to a variety of air pollutants, including PM. This review focuses on the main effects of PM on human health, with an emphasis on the role of inflammation.

Neuropathology changed by 3- and 6-months low-level PM2.5 inhalation exposure in spontaneously hypertensive rats

BACKGROUND

Epidemiological evidence has linked fine particulate matter (PM2.5) to neurodegenerative diseases; however, the toxicological evidence remains unclear. The objective of this study was to investigate the effects of PM2.5 on neuropathophysiology in a hypertensive animal model. We examined behavioral alterations (Morris water maze), lipid peroxidation (malondialdehyde (MDA)), tau and autophagy expressions, neuron death, and caspase-3 levels after 3 and 6 months of whole-body exposure to urban PM2.5 in spontaneously hypertensive (SH) rats.

RESULTS

SH rats were exposed to S-, K-, Si-, and Fe-dominated PM2.5 at 8.6 ± 2.5 and 10.8 ± 3.8 μg/m3 for 3 and 6 months, respectively. We observed no significant alterations in the escape latency, distance moved, mean area crossing, mean time spent, or mean swimming velocity after PM2.5 exposure. Notably, levels of MDA had significantly increased in the olfactory bulb, hippocampus, and cortex after 6 months of PM2.5 exposure (p < 0.05). We observed that 3 months of exposure to PM2.5 caused significantly higher expressions of t-tau and p-tau in the olfactory bulb (p < 0.05) but not in other brain regions. Beclin 1 was overexpressed in the hippocampus with 3 months of PM2.5 exposure, but significantly decreased in the cortex with 6 months exposure to PM2.5. Neuron numbers had decreased with caspase-3 activation in the cerebellum, hippocampus, and cortex after 6 months of PM2.5 exposure.

CONCLUSIONS

Chronic exposure to low-level PM2.5 could accelerate the development of neurodegenerative pathologies in subjects with hypertension.

Notch1-mediated inflammation is associated with endothelial dysfunction in human brain microvascular endothelial cells upon particulate matter exposure

Exposure to atmospheric particulate matter (PM) is an emerging risk factor for the pathogenesis of several diseases in humans, including cerebrovascular diseases. However, the mechanisms underlying PM-induced endothelial dysfunction are currently unclear. In this study, we examined how PM leads to endothelial dysfunction in human brain microvascular endothelial cells (HBMECs). We demonstrated that PM₁₀ exposure (up to 25 μg/mL) increase Notch1 cleavage, and it regulates endothelial dysfunction through NICD-mediated inflammation and senescence. PM₁₀-induced NICD signaling causes increased expression of interleukin-1 beta (IL-1β) and enhances characteristics of cellular senescence, which leads to increased endothelial permeability in HBMECs. Knockdown of Notch1 by siRNA blocks PM₁₀-induced endothelial dysfunction via the suppression of inflammation and senescence. Furthermore, we found that Notch1-mediated inflammation accelerates endothelial senescence, which eventually leads to endothelial dysfunction. Altogether, our data suggest that Notch1 and NICD are potential target regulators for the prevention of cerebrovascular endothelial dysfunction induced by ambient air pollutants such as PM.

Ambient carbon monoxide exposure and elevated risk of mortality in the glioblastoma patients: A double-cohort retrospective observational study

An increasing number of studies indicate air pollutants infiltrate into the brain. We aimed to find the association of cumulative air pollution exposure in the main body of primary brain tumor: glioblastoma (GBM). In this double-cohort, retrospective analysis study with a protocol, we compared the health effect of air pollution on the GBM patients from the SEER (Surveillance, Epidemiology, and End Results Program) in 27 U.S. counties from 10 states and GBM patients of Severance cohort of Korea. From 2000 to 2015, 10621 GBM patients of the SEER were individually evaluated for the cumulative average exposure for each pollutant, and 9444 (88.9%) mortality events were reported. From 2011 to 2018, 398 GBM patients of the Severance with the same protocol showed 259 (65.1%) mortality events. The multi-pollutant models show that the association level of risk with CO is increased in the SEER (HR 1.252; 95% CI 1.141-1.373) with an increasing linear trend of relative death rate in the spline curve. The Severance GBM data showed such a statistically significant result of the health impact of CO on GBM patients. The overall survival gain of the less exposure group against CO was 2 and 3 months in the two cohorts. Perioperative exposure to CO may increase the risk of shorter survival of GBM patients of the SEER and the Severance cohort.

Association between coarse particulate matter and inflammatory and hemostatic markers in a cohort of midlife women

BACKGROUND

Exposure to particulate matter air pollution has been associated with cardiovascular disease (CVD) morbidity and mortality; however, most studies have focused on fine particulate matter (PM_2.5) exposure and CVD. Coarse particulate matter (PM_10-2.5) exposure has not been extensively studied, particularly for long-term exposure, and the biological mechanisms remain uncertain.

METHODS

We examined the association between ambient concentrations of PM_10-2.5 and inflammatory and hemostatic makers that have been linked to CVD. Annual questionnaire and clinical data were obtained from 1694 women (≥ 55 years old in 1999) enrolled in the longitudinal Study of Women's Health Across the Nation (SWAN) at six study sites from 1999 to 2004. Residential locations and the USEPA air monitoring network measurements were used to assign exposure to one-year PM_10-2.5, as well as co-pollutants. Linear mixed-effects regression models were used to describe the association between PM_10-2.5 exposure and markers, including demographic, health and other covariates.

RESULTS

Each interquartile (4 μg/m³) increase in one-year PM_10-2.5 exposure was associated with a 5.5% (95% confidence interval [CI]: 1.8, 9.4%) increase in levels of plasminogen activator inhibitor-1 (PAI-1) and 4.1% (95% CI: - 0.1, 8.6%) increase in high-sensitivity C-creative Protein (hs-CRP). Stratified analyses suggested that the association with PAI-1 was particularly strong in some subgroups, including women who were peri-menopausal, were less educated, had a body mass index lower than 25, and reported low alcohol consumption. The association between PM_10-2.5 and PAI-1 remained unchanged with adjustment for PM_2.5, ozone, nitrogen dioxide, and carbon monoxide.

CONCLUSIONS

Long-term PM_10-2.5 exposure may be associated with changes in coagulation independently from PM_2.5, and thus, contribute to CVD risk in midlife women.

Unraveling the blood transcriptome after real-life exposure of Wistar-rats to PM2.5, PM1 and water-soluble metals in the ambient air

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Development of a “real-life” exposure system to ambient PM1 and PM2.5 particles for Wistar rats.

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Blood transcriptome analysis identified differentially expressed genes as candidate biomarkers in PM1 and PM2.5 groups.

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Pathway analysis revealed differentially regulated gene expression in inflammation signaling.

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Identification of candidate metals for possible correlation with the identified candidate genes leading to the development of AOPs.

Exposure to particulate matter (PM) is one of the most important environmental issues in Europe with major health impact. Various sizes of PM are suspended in the atmosphere and contributes to ambient air pollution. The current study aimed to explore the differential gene expression in blood, and the effect on the respective biological signaling pathways in Wistar rats, after exposure to PM2.5 and PM1 ambient air particles for an eight-week period. A control group was included with animals breathing non-filtered atmospheric air. In parallel, filtered PM2.5 and PM1 was collected in separate samplers. The results after whole genome microarray analysis showed 23 differentially expressed genes (DEGs) between control and PM2.5 group. In addition, pairwise comparison between control and PM1 group displayed 5635 DEGs linked to 69 biological pathways involved in inflammatory response, cell cycle and carcinogenicity. The smaller the size of the inhaled particles, the more gene alterations are triggered compared to non-filtered air group. More specifically, in inflammation signaling procedures differentially regulated gene expression was shown for interleukin-4 (IL-4), IL-7, IL-1, IL-5, IL-9, IL-6 and IL-2. We have identified that RASGFR1, TRIM65, TRIM33, PLEKHB1, CAR4, S100A8, S100A9, ALPL, NP4 and the PROK2 genes are potential targets for the development of adverse outcome pathways (AOPs) due to “real-life” exposure of Wistar rats. Particle measurements during the exposure period showed elevated concentrations of Fe, Mn and Zn in both PM1 and PM2.5 filter fractions, and of Cu in PM2.5. In addition, water-soluble concentration of metals showed significant differences between PM1 and PM2.5 fractions for V, Zn, As, Pb and Mn. In summary, in this study specific gene biomarkers of exposure to ambient air have been identified and heavy metals that are possibly linked to their altered regulation have been found. The results of this research will pave the way for the development of novel AOPs concerning the health effects of the environmental pollution.

Fine particulate matter exposure during childhood relates to hemispheric-specific differences in brain structure

BACKGROUND

Emerging findings have increased concern that exposure to fine particulate matter air pollution (aerodynamic diameter ≤ 2.5 μm; PM2.5) may be neurotoxic, even at lower levels of exposure. Yet, additional studies are needed to determine if exposure to current PM2.5 levels may be linked to hemispheric and regional patterns of brain development in children across the United States.

OBJECTIVES

We examined the cross-sectional associations between geocoded measures of concurrent annual average outdoor PM2.5 exposure, regional- and hemisphere-specific differences in brain morphometry and cognition in 10,343 9- and 10- year-old children.

METHODS

High-resolution structural T1-weighted brain magnetic resonance imaging (MRI) and NIH Toolbox measures of cognition were collected from children at ages 9-10 years. FreeSurfer was used to quantify cortical surface area, cortical thickness, as well as subcortical and cerebellum volumes in each hemisphere. PM2.5 concentrations were estimated using an ensemble-based model approach and assigned to each child's primary residential address collected at the study visit. We used mixed-effects models to examine regional- and hemispheric- effects of PM2.5 exposure on brain estimates and cognition after considering nesting of participants by familial relationships and study site, adjustment for socio-demographic factors and multiple comparisons.

RESULTS

Annual residential PM2.5 exposure (7.63 ± 1.57 µg/m3) was associated with hemispheric specific differences in gray matter across cortical regions of the frontal, parietal, temporal and occipital lobes as well as subcortical and cerebellum brain regions. There were hemispheric-specific associations between PM2.5 exposures and cortical surface area in 9/31 regions; cortical thickness in 22/27 regions; and volumes of the thalamus, pallidum, and nucleus accumbens. We found neither significant associations between PM2.5 and task performance on individual measures of neurocognition nor evidence that sex moderated the observed associations.

DISCUSSION

Even at relatively low-levels, current PM2.5 exposure across the U.S. may be an important environmental factor influencing patterns of structural brain development in childhood. Prospective follow-up of this cohort will help determine how current levels of PM2.5 exposure may affect brain development and subsequent risk for cognitive and emotional problems across adolescence.

Air quality intervention during the Nanjing youth olympic games altered PM sources, chemical composition, and toxicological responses

Ambient particulate matter (PM) is a leading global environmental health risk. Current air quality regulations are based on airborne mass concentration. However, PM from different sources have distinct chemical compositions and varied toxicity. Connections between emission control measures, air quality, PM composition, and toxicity remain insufficiently elucidated. The current study assessed the composition and toxicity of PM collected in Nanjing, China before, during, and after an air quality intervention for the 2014 Youth Olympic Games. A co-culture model that mimics the alveolar epithelium with the associated macrophages was created using A549 and THP-1 cells. These cells were exposed to size-segregated inhalable PM samples. The composition and toxicity of the PM samples were influenced by several factors including seasonal variation, emission sources, and the air quality intervention. For example, we observed a size-dependent shift in particle mass concentrations during the air quality intervention with an emphasized proportion of smaller particles (PM_2.5) present in the air. The roles of industrial and fuel combustion and traffic emissions were magnified during the emission control period. Our analyses revealed that the PM samples demonstrated differential cytotoxic potencies at equal mass concentrations between sampling periods, locations, and time of day, influenced by variations in the predominant emission sources. Coal combustion and industrial emissions were the most important sources affecting the toxicological responses and displayed the least variation in emission contributions between the sampling periods. In conclusion, emission control mitigated cytotoxicity and oxidative stress for particles larger than 0.2 μm, but there was inadequate evidence to determine if it was the key factor reducing the harmful effects of PM_0.2.

Association Between Outdoor Air Pollution and Risk of Malignant and Benign Brain Tumors: The Multiethnic Cohort Study

BACKGROUND

There are increasing concerns about the potential impact of air pollution on chronic brain inflammation and microglia cell activation, but evidence of its carcinogenic effects is limited.

METHODS

We used kriging interpolation and land use regression models to estimate long-term air pollutant exposures of oxides of nitrogen (NOx, NO2), kriging interpolation for ozone (O3), carbon monoxide, and particulate matter (PM2.5, PM10), and nearest monitoring station measurements for benzene for 103 308 men and women from the Multiethnic Cohort, residing largely in Los Angeles County from recruitment (1993-1996) through 2013. We used Cox proportional hazards models to examine the associations between time-varying pollutants and risk of malignant brain cancer (94 men, 116 women) and meningioma (130 men, 425 women) with adjustment for sex, race and ethnicity, neighborhood socioeconomic status, smoking, occupation, and other covariates. Stratified analyses were conducted by sex and race and ethnicity.

RESULTS

Brain cancer risk in men increased in association with exposure to benzene (hazard ratio [HR] = 3.52, 95% confidence interval [CI] = 1.55 to 7.55) and PM10 (HR = 1.80, 95% CI = 1.00 to 3.23). Stronger associations with PM10 (HR = 3.02, 95% CI = 1.26 to 7.23), O3 (HR = 2.93, 95% CI = 1.09 to 7.88), and benzene (HR = 4.06, 95% CI = 1.17 to 18.2) were observed among Latino men. Air pollution was unrelated to risk of meningioma except that O3 exposure was associated with risk in men (HR = 1.77, 95% CI = 1.02 to 3.06). Brain cancer risk in women was unrelated to air pollution exposures.

CONCLUSIONS

Confirmation of these sex differences in air pollution-brain cancer associations and the stronger findings in Latino men in additional diverse populations is warranted.

Association between coarse particulate matter (PM10-2.5) and nasopharyngeal carcinoma among Taiwanese men

The nasopharyngeal tract traps mainly coarse particles in inhaled air. Soluble carcinogenic compounds, endotoxins, and trace metals contained in these particles are potential causes of inflammation and oxidative stress which could enhance carcinogenesis. The aim of this study was to determine the association between coarse particulate matter (PM10-2.5) and nasopharyngeal cancer (NPC). A total of 521,098 men (355 cases and 520,743 non-cases), aged ≥40 years were included in this study. Data were retrieved from the Taiwan Cancer Registry, the Adult Preventive Medical Services Database, and the Air Quality Monitoring Database. PM10-2.5 was significantly associated with a higher risk of NPC after adjusting for SO2, NOx, O3, age, body mass index, smoking, alcohol drinking, betel nut chewing, exercise, hypertension, diabetes, and hyperlipidemia. With PM10-2.5<20.44 μg/m3 as the reference, the ORs and 95% CIs were 1.47; 1.03-2.11, 1.34; 0.94-1.91, and 1.68; 1.16-2.44 for 20.44≤PM10-2.5<24.08, 24.08≤PM10-2.5<29.27, and PM10-2.5≥29.27 μg/m3, respectively. PM10-2.5 remained significantly associated with a higher risk of NPC after further adjustments were made for the aforementioned covariates and PM2.5 The ORs; 95% CIs were 1.42; 0.96 to 2.12, 1.41; 0.94 to 2.10, and 1.71; 1.10 to 2.66 for 20.44≤PM10-2.5<24.08, 24.08≤PM10-2.5<29.27, and PM10-2.5≥29.27 μg/m3, respectively. In conclusion, PM10-2.5 was significantly associated with a higher risk of NPC in Taiwanese men.

Aspects of the immune system that impact brain function

The conditions required for effective immune responses to viral or bacterial organisms and chemicals of exogenous origin and to intrinsic molecules of abnormal configuration, are briefly outlined. This is followed by a discussion of endocrine and environmental factors that can lead to excessive continuation of immune activity and persistent elevation of inflammatory responses. Such disproportionate activity becomes increasingly pronounced with aging and some possible reasons for this are considered. The specific vulnerability of the nervous system to prolonged immune events is involved in several disorders frequently found in the aging brain. In addition of being a target for inflammation associated with neurodegenerative disease, the nervous system is also seriously impacted by systemically widespread immune disturbances since there are several means by which immune information can access the CNS. The activation of glial cells and cells of non-nervous origin that form the basis of immune responses within the brain, can occur in differing modes resulting in widely differing consequences. The events underlying the relatively frequent occurrence of derangement and hyperreactivity of the immune system are considered, and a few potential ways of addressing this common condition are described.

Outdoor Air Pollution and Brain Structure and Function From Across Childhood to Young Adulthood: A Methodological Review of Brain MRI Studies

Outdoor air pollution has been recognized as a novel environmental neurotoxin. Studies have begun to use brain Magnetic Resonance Imaging (MRI) to investigate how air pollution may adversely impact developing brains. A systematic review was conducted to evaluate and synthesize the reported evidence from MRI studies on how early-life exposure to outdoor air pollution affects neurodevelopment. Using PubMed and Web of Knowledge, we conducted a systematic search, followed by structural review of original articles with individual-level exposure data and that met other inclusion criteria. Six studies were identified, each sampled from 3 cohorts of children in Spain, The Netherlands, and the United States. All studies included a one-time assessment of brain MRI when children were 6–12 years old. Air pollutants from traffic and/or regional sources, including polycyclic aromatic hydrocarbons (PAHs), nitrogen dioxide, elemental carbon, particulate matter (<2.5 or <10 μm), and copper, were estimated prenatally (n = 1), during childhood (n = 3), or both (n = 2), using personal monitoring and urinary biomarkers (n = 1), air sampling at schools (n = 4), or a land-use regression (LUR) modeling based on residences (n = 2). Associations between exposure and brain were noted, including: smaller white matter surface area (n = 1) and microstructure (n = 1); region-specific patterns of cortical thinness (n = 1) and smaller volumes and/or less density within the caudate (n = 3); altered resting-state functional connectivity (n = 2) and brain activity to sensory stimuli (n = 1). Preliminary findings suggest that outdoor air pollutants may impact MRI brain structure and function, but limitations highlight that the design of future air pollution-neuroimaging studies needs to incorporate a developmental neurosciences perspective, considering the exposure timing, age of study population, and the most appropriate neurodevelopmental milestones.

The intrinsic and extrinsic factors that contribute to proteostasis decline and pathological protein misfolding

Proteostasis refers to the ability of cells to maintain the health of the proteome. Highly conserved quality control mechanisms exist to maintain proteostasis. These include the heat shock response, the unfolded protein response, and protein clearance/degradation pathways. Together, these mechanisms and others comprise the proteostasis network. This network is under constant assault and is strikingly sensitive to changes in the protein folding environment, resulting in proteostasis collapse under certain conditions. Here, the intrinsic and extrinsic stresses experienced by the proteostasis network are explored. The intrinsic stresses include genetic background as well as transcriptional and translational fidelity. These cause changes in the abundance or amino acid sequence of cellular proteins. Extrinsic stresses refer to environmental perturbation of the proteome, such as those caused by temperature stress, oxidative stress, air pollution and cigarette smoke. As the stress to the proteome exceeds the capacity of the proteostasis network, progressive neurodegenerative diseases of aging, such as Alzheimer's disease and Huntington's disease are more likely to ensue.

Environmental pollution is associated with increased risk of psychiatric disorders in the US and Denmark

The search for the genetic factors underlying complex neuropsychiatric disorders has proceeded apace in the past decade. Despite some advances in identifying genetic variants associated with psychiatric disorders, most variants have small individual contributions to risk. By contrast, disease risk increase appears to be less subtle for disease-predisposing environmental insults. In this study, we sought to identify associations between environmental pollution and risk of neuropsychiatric disorders. We present exploratory analyses of 2 independent, very large datasets: 151 million unique individuals, represented in a United States insurance claims dataset, and 1.4 million unique individuals documented in Danish national treatment registers. Environmental Protection Agency (EPA) county-level environmental quality indices (EQIs) in the US and individual-level exposure to air pollution in Denmark were used to assess the association between pollution exposure and the risk of neuropsychiatric disorders. These results show that air pollution is significantly associated with increased risk of psychiatric disorders. We hypothesize that pollutants affect the human brain via neuroinflammatory pathways that have also been shown to cause depression-like phenotypes in animal studies.

Continuous Inhalation Exposure to Fungal Allergen Particulates Induces Lung Inflammation While Reducing Innate Immune Molecule Expression in the Brainstem

Continuous exposure to aerosolized fine (particle size ≤2.5 µm) and ultrafine (particle size ≤0.1 µm) particulates can trigger innate inflammatory responses in the lung and brain depending on particle composition. Most studies of manmade toxicants use inhalation exposure routes, whereas most studies of allergens use soluble solutions administered via intranasal or injection routes. Here, we tested whether continuous inhalation exposure to aerosolized Alternaria alternata particulates (a common fungal allergen associated with asthma) would induce innate inflammatory responses in the lung and brain. By designing a new environmental chamber able to control particle size distribution and mass concentration, we continuously exposed adult mice to aerosolized ultrafine Alternaria particulates for 96 hr. Despite induction of innate immune responses in the lung, induction of innate immune responses in whole brain samples was not detected by quantitative polymerase chain reaction or flow cytometry. However, exposure did trigger decreases in Arginase 1, inducible nitric oxide synthase, and tumor necrosis factor alpha mRNA in the brainstem samples containing the central nervous system respiratory circuit (the dorsal respiratory group, ventral respiratory group, and the pre-Bötzinger and Bötzinger complexes). In addition, a significant decrease in the percentage of Toll-like receptor 2-expressing brainstem microglia was detected by flow cytometry. Histologic analysis revealed a significant decrease in Iba1 but not glial fibrillary acidic protein immunoreactivity in both the brainstem and the hippocampus. Together these data indicate that inhalation exposure to a natural fungal allergen under conditions sufficient to induce lung inflammation surprisingly causes reductions in baseline expression of select innate immune molecules (similar to that observed during endotoxin tolerance) in the region of the central nervous system controlling respiration.