Associations of urinary polycyclic aromatic hydrocarbon metabolites and blood pressure with the mediating role of cytokines: A panel study among children

Childhood exposure to polycyclic aromatic hydrocarbons (PAHs) and cardiometabolic indicators in childhood and adolescence: findings from a cohort study in rural Bangladesh

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with cardiovascular diseases in adulthood, but studies examining childhood origins are scarce.

OBJECTIVE

To examine associations of childhood PAH exposure with cardiometabolic risk indicators in childhood and adolescence along with differences by sex.

METHODS

Urinary PAH metabolites [Σ1,2,3-hydroxyphenanthrene (Σ1,2,3-OH Phe), 1-hydroxypyrene (1-OH Pyr), and Σ2,3-hydroxyfluorene (Σ2,3-OH Flu)] were measured in 9-year-olds from the MINIMat cohort in Bangladesh (n=196), using liquid chromatography with tandem mass spectrometry. Cardiometabolic indicators [lipids, C-reactive protein (CRP), insulin resistance (HOMA2 IR), blood pressure, anthropometry, and a composite cardiometabolic risk score (CMRS)] were assessed at 9 and 15 years. Associations of PAH metabolites (log2-transformed) with cardiometabolic indicators were assessed using multivariable-adjusted linear and logistic regression models.

RESULTS

In all children, urinary 1-OH Pyr (median: 1.6 ng/mL) was positively associated with body mass index z-score at 9 and 15 years, and with triglyceride/high-density lipoprotein (HDL), cholesterol/HDL ratios, waist circumference, CMRS, and CRP at 15 years. After sex stratification, consistent associations were mainly observed in girls, especially with outcomes at age 15, where both urinary 1-OH Pyr and Σ1,2,3-OH Phe concentrations were inversely associated with HDL, and positively associated with cholesterol/HDL ratios and CMRS. Urinary 1-OH Pyr was also positively associated with girls' triglyceride/HDL ratio, HOMA2 IR, waist circumference, and CRP.

CONCLUSIONS

Our associations of childhood PAH exposure with cardiometabolic indicators in childhood and adolescence differed by sex. In girls, increased adiposity, indications of altered lipid profile and metabolic function were detected while boys seem incongruently affected.

Air pollution and systemic immune biomarkers in early life: A systematic review

INTRODUCTION

Children's rapid development and immature immune systems place them at a higher risk of adverse health outcomes associated with air pollution exposure. However, the specific mechanisms in which air pollution mediates immune dysregulation in youth are poorly understood. Thus, we aimed to systematically review the available epidemiological evidence surrounding the effects of indoor and ambient air pollution exposure on systemic immune biomarkers in early life (from birth to 18 years old).

METHODS

based on PRISMA guidelines, we developed a systematic search strategy and defined inclusion and exclusion criteria to retrieve publications from PubMed, SCOPUS and Web of Science published up to August 10th, 2024. Quality assessment and evidence evaluation were also performed. Five independent reviewers participated in the process.

RESULTS

In total, 96 studies were included. We found limited evidence of a causal relationship between prenatal ambient PM2.5 and reduced T-cells (CD3+ and CD8+), as well as between postnatal PM exposure and increased IgE levels or allergic sensitization. For the rest of exposure-outcome combinations we classified the evidence as inadequate, mainly due to the limited number of studies available or the lack of consistency in the results obtained among them. This was particularly the case for indoor air pollution research, for which only 12 studies were available.

CONCLUSION

the present systematic review highlights the need for further research on the impacts of air pollution on youth's immune system. We provided recommendations for future studies in order to better understand the early subclinical and clinical effects of air pollution and the underlying biological pathways, and identify the dynamics of the innate and adaptive immune responses to environmental threats. Considering the significance of childhood immunity on health outcomes within all stages of life, and the globally extensive burden of air pollution exposure, further research on this topic should be prioritized.

Associations among urinary 1-hydroxypyrene level, oxidative stress, and high blood pressure: A panel study among elderly Koreans

Polycyclic aromatic hydrocarbons (PAHs) are environmental carcinogens. However, there is limited evidence for the relations between PAHs exposure and blood pressure (BP) with the mediating role of oxidative stress. Therefore, in this study, we evaluated relations among PAHs exposure, oxidative stress, and BP in the elderly population. We measured the levels of 1-hydroxypyrene (1-OHP), an indicator of PAHs exposure, and malondialdehyde (MDA), an oxidative stress marker, in urine samples repeatedly collected from 560 elderly persons aged ≥60 years, and then evaluated the relations among 1-OHP level, MDA level, and systolic or diastolic BP (SBP or DBP) measured on the day of urine collection. Urinary 1-OHP level was significantly associated with both MDA level (β = 0.19 and p < 0.0001) and BP (β = 1.72 and p < 0.0001 for SBP; and β = 1.24 and p < 0.0001 for DBP). Furthermore, urinary MDA level was also significantly associated with BP (β = 4.35 and p < 0.0001 for SBP; and β = 2.51 and p < 0.0001 for DBP). The trend for the change of SBP and DBP by 1-OHP quartile was more apparent in the elderly female participants (ptrend<0.0001 for SBP; and ptrend<0.0001 for DBP) compared with the elderly male participants (ptrend = 0.8351 for SBP; and ptrend = 0.3736 for DBP). To explore the mediating role of oxidative stress in the relation between 1-OHP level and SBP or DBP, we repeated these analyses after adjustment for the MDA levels. The increase in BP by 1-OHP exposure was largely mediated by the production of MDA (96.3% for SBP and 94.7% for DBP). These results revealed that PAHs exposure may increase BP through the mediation of oxidative stress.

Effects of Polycyclic Aromatic Hydrocarbon Exposure and Telomere Length and their Interaction on Blood Lipids in Coal Miners

OBJECTIVE

This study aimed to investigate the effects of polycyclic aromatic hydrocarbon (PAH) exposure and telomere length on lipids in coal miners.

METHODS

Basic personal information of 637 coal miners was collected by questionnaire survey. Logistic regression, the Bayesian kernel machine regression model, and weighted quantile sum regression were used to analyze the effects of PAH metabolites and telomere length and their interactions on blood lipids.

RESULTS

High exposure to 9-hydroxyphenanthrene (OR = 1.586, 95% CI: 1.011-2.487) and telomere shortening (OR = 1.413, 95% CI: 1.005-1.985) were associated with dyslipidemia. Weighted quantile sum results showed that 9-hydroxyphenanthrene accounted for the largest proportion of dyslipidemia (weight = 0.66). The interaction results showed that high 9-hydroxyphenanthrene exposure and short telomeres were risk factors for dyslipidemia in coal miners (OR = 2.085, 95% CI: 1.121-3.879). Conclusions: Our findings suggest that 9-hydroxyphenanthrene and shorter telomeres are risk factors for dyslipidemia, and their interaction increases the risk of dyslipidemia.

Differential Susceptibility to Benzo[a]pyrene Exposure during Gestation and Lactation in Mice with Genetic Variations in the Aryl Hydrocarbon Receptor and Cyp1 Genes

Polycyclic aromatic hydrocarbons are ubiquitous air pollutants, with additional widespread exposure in the diet. PAH exposure has been linked to adverse birth outcomes and long-term neurological consequences. To understand genetic differences that could affect susceptibility following developmental exposure to polycyclic aromatic hydrocarbons, we exposed mice with variations in the aryl hydrocarbon receptor and the three CYP1 enzymes from gestational day 10 (G10) to weaning at postnatal day 25 (P25). We found unexpectedly high neonatal lethality in high-affinity AhrbCyp1b1(-/-) knockout mice compared with all other genotypes. Over 60% of BaP-exposed pups died within their first 5 days of life. There was a significant effect of BaP on growth rates in surviving pups, with lower weights observed from P7 to P21. Again, AhrbCyp1b1(-/-) knockout mice were the most susceptible to growth retardation. Independent of treatment, this line of mice also had impaired development of the surface righting reflex. We used high-resolution mass spectrometry to measure BaP and metabolites in tissues from both dams and pups. We found the highest BaP levels in adipose from poor-affinity AhrdCyp1a2(-/-) dams and identified three major BaP metabolites (BaP-7-OH, BaP-9-OH, and BaP-4,5-diol), but our measurements were limited to a single time point. Future work is needed to understand BaP pharmacokinetics in the contexts of gestation and lactation and how differential metabolism leads to adverse developmental outcomes.