Association between PM2.5-bound metals and pediatric respiratory health in Guangzhou: An ecological study investigating source, health risk, and effect

Frequentist Grouped Weighted Quantile Sum Regression for Correlated Chemical Mixtures

As individuals are exposed to a myriad of potentially harmful pollutants every day, it is important to determine which actors have the greatest influence on health outcomes. However, jointly modeling the associations of multiple pollutant exposures is often hindered by the presence of highly correlated chemicals originating from a common source. A popular approach to analyzing associations between a disease outcome and several highly correlated exposures is Weighted Quantile Sum Regression (WQSR) modeling. WQSR provides increased stability in estimating model parameters but requires data splitting to estimate individual and group effects of chemicals, which reduces the power of the approach. A recent Bayesian implementation of WQSR regression provides a model fitting procedure that avoids data splitting at the cost of high computational expense on large data. In this paper, we introduce a Frequentist Grouped Weighted Quantile Sum Regression (FGWQSR) model that can be fitted efficiently to large datasets without requiring data splitting. FGWQSR produces estimates of the joint effect of mixture groups and of individual chemicals, and likelihood-ratio-based tests that account for FGWQSR's non-standard asymptotics. We demonstrate that FGWQSR is well calibrated for type-I errors while outperforming both Bayesian Grouped Weighted Quantile Sum Regression and Quantile Logistic Regression in terms of statistical power to detect the effects of mixture groups and individual chemicals. In addition, we show that FGWQSR is robust to model misspecification and can be fitted on large datasets in a fraction of the time required for BGWQSR. We apply FGWQSR to a dataset of 317 767 mother-child pairs with exposure profiles generated by chemical transport models to study the associations between several components found in particulate matter with an aerodynamic diameter smaller than 2.5μ m $$ \mu \mathrm{m} $$ (PM  2 . 5 $$ {}_{2.5} $$ ) and child Autism Spectrum Disorder (ASD) diagnosis before age 5. PM  2 . 5 $$ {}_{2.5} $$ copper and PM  2 . 5 $$ {}_{2.5} $$ crustal material are found to be statistically significantly associated with ASD diagnosis by five years of age.

PM10 exposure induces bronchial hyperresponsiveness by upreguating acetylcholine muscarinic 3 receptor

Exposure to particulate matter (PM10) can induce respiratory diseases that are closely related to bronchial hyperresponsiveness. However, the involved mechanism remains to be fully elucidated. This study aimed to demonstrate the effects of PM10 on the acetylcholine muscarinic 3 receptor (CHRM3) expression and the role of the ERK1/2 pathway in rat bronchial smooth muscle. A whole-body PM10 exposure system was used to stimulate bronchial hyperresponsiveness in rats for 2 and 4 months, accompanied by MEK1/2 inhibitor U0126 injection. The whole-body plethysmography system and myography were used to detect the pulmonary and bronchoconstrictor function, respectively. The mRNA and protein levels were determined by Western blotting, qPCR, and immunofluorescence. Enzyme-linked immunosorbent assay was used to detect the inflammatory cytokines. Compared with the filtered air group, 4 months of PM10 exposure significantly increased CHRM3-mediated pulmonary function and bronchial constriction, elevated CHRM3 mRNA and protein expression levels on bronchial smooth muscle, then induced bronchial hyperreactivity. Additionally, 4 months of PM10 exposure caused an increase in ERK1/2 phosphorylation and increased the secretion of inflammatory factors in bronchoalveolar lavage fluid. Treatment with the MEK1/2 inhibitor, U0126 inhibited the PM10 exposure-induced phosphorylation of the ERK1/2 pathway, thereby reducing the PM10 exposure-induced upregulation of CHRM3 in bronchial smooth muscle and CHRM3-mediated bronchoconstriction. U0126 could rescue PM10 exposure-induced pathological changes in the bronchus. In conclusion, PM10 exposure can induce bronchial hyperresponsiveness in rats by upregulating CHRM3, and the ERK1/2 pathway may be involved in this process. These findings could reveal a potential therapeutic target for air pollution induced respiratory diseases.

Fine particulate matter manipulates immune response to exacerbate microbial pathogenesis in the respiratory tract

Particulate matter with a diameter ≤2.5 μm (PM2.5) poses a substantial global challenge, with a growing recognition of pathogens contributing to diseases associated with exposure to PM2.5 Recent studies have focused on PM2.5, which impairs the immune cells in response to microbial infections and potentially contributes to the development of severe diseases in the respiratory tract. Accordingly, changes in the respiratory immune function and microecology mediated by PM2.5 are important factors that enhance the risk of microbial pathogenesis. These factors have garnered significant interest. In this review, we summarise recent studies on the potential mechanisms involved in PM2.5-mediated immune system disruption and exacerbation of microbial pathogenesis in the respiratory tract. We also discuss crucial areas for future research to address the gaps in our understanding and develop effective strategies to combat the adverse health effects of PM2.5.

Long-term exposure to PM2.5 leads to mitochondrial damage and differential expression of associated circRNA in rat hepatocytes

Fine particulate matter (PM2.5) is one of the four major causes of mortality globally. The objective of this study was to investigate the mechanism underlying liver injury following exposure to PM2.5 and the involvement of circRNA in its regulation. A PM2.5 respiratory tract exposure model was established in SPF SD male rats with a dose of 20 mg/kg, and liver tissue of rats in control group and PM2.5-exposed groups rats were detected. The results of ICP-MS showed that Mn, Cu and Ni were enriched in the liver. HE staining showed significant pathological changes in liver tissues of PM2.5-exposed group, transmission electron microscopy showed significant changes in mitochondrial structure of liver cells, and further mitochondrial function detection showed that the PM2.5 exposure resulted in an increase in cell reactive oxygen species content and a decrease in mitochondrial transmembrane potential, while the expression of SOD1 and HO-1 antioxidant oxidase genes was upregulated. Through high-throughput sequencing of circRNAs, we observed a significant down-regulation of 10 and an up-regulation of 17 circRNAs in the PM2.5-exposed groups. The functional enrichment and pathway analyses indicated that the differentially expressed circRNAs by PM2.5 exposure were primarily associated with processes related to protein ubiquitination, zinc ion binding, peroxisome function, and mitochondrial regulation. These findings suggest that the mechanism underlying liver injury induced by PM2.5-exposure may be associated with mitochondrial impairment resulting from the presence of heavy metal constituents. Therefore, this study provides a novel theoretical foundation for investigating the molecular mechanisms underlying liver injury induced by PM2.5 exposure.

Association between ambient air pollutants and short-term mortality risks during 2015-2019 in Guangzhou, China

With the development of technology and industry, the problem of global air pollution has become difficult to ignore. We investigated the association between air pollutant concentrations and daily all-cause mortality and stratified the analysis by sex, age, and season. Data for six air pollutants [fine particulate matter (PM2.5), inhalable particles (PM10), nitric dioxide (NO2), sulfur dioxide (SO2), ozone (O3), and carbon monoxide (CO)] and daily mortality rates were collected from 2015 to 2019 in Guangzhou, China. A time-series study using a quasi-Poisson generalized additive model was used to examine the relationships between environmental pollutant concentrations and mortality. Mortality data for 296,939 individuals were included in the analysis. The results showed that an increase of 10 μg/m3 in the concentrations of PM2.5, PM10, SO2, O3, NO2, and CO corresponded to 0.84% [95% confidence interval (CI): 0.47, 1.21%], 0.70% (0.44, 0.96%), 3.59% (1.77, 5.43%), 0.21% (0.05, 0.36%), 1.06% (0.70, 1.41%), and 0.05% (0.02, 0.09%), respectively. The effects of the six air pollutants were more significant for male individuals than female individuals, the cool season than the warm season, and people 75 years or older than those younger than 75 years. PM2.5, PM10, SO2, and NO2 were all associated with neoplasms and circulatory and respiratory diseases. The two-pollutant models found that PM2.5, PM10, and NO2 may independently affect the risk of mortality. The results showed that exposure to PM2.5, PM10 and NO2 may increase the risk of daily all-cause excessive mortality in Guangzhou.

Short-term effects of air pollution on hospitalization of children with acute upper respiratory infections: A time series analysis in Lanzhou, China

OBJECTIVE

Short-term air pollution exposure is correlated with childhood acute upper respiratory infections (AURI) hospitalizations. We surveyed the relationship between AURI hospitalizations and air pollutant concentrations in children aged 0-14 years from 1 January 2014 to 31 December 2019 in Lanzhou City.

METHODS

We collected both data on air pollutant concentrations and children's AURI hospitalizations during the study period. Distributional lagged nonlinear models were adopted to assess the short-term effects of air pollutants on children's AURI hospitalizations. We also performed subgroup analysis and sensitivity analysis.

RESULTS

A total of 15,881 children were hospitalized for AURI during the study period. The results showed that for each 10 µg/m3 increase in PM2.5 , SO2 , and NO2 concentrations at lag0-6, the relative risk (RR) values for children hospitalized for AURI were RR = 1.0247 (95% CI: 1.0092,1.0405), RR = 1.0928 (95% CI: 1.0562, 1.1308), and RR = 1.0715 (95% CI: 1.0495, 1.0940), respectively. PM10 was significantly associated with AURI hospitalization in children only at lag0, RR = 1.0028 (95% CI: 1.0000, 1.0056).

CONCLUSION

Short-term exposures to PM2.5 , PM10 , SO2 , and NO2 all increase the risk of AURI hospitalization in children variously.