Polychlorinated biphenyls and risk of metabolic syndrome and comparison with the risk of diabetes: A systematic review and meta-analysis

Subacute exposure of male adolescent rats to 2,2',5,5'-tetrachlorobiphenyl-4-ol via a polymeric implant causes gene expression changes in the brain and metabolomic disruption in serum

Polychlorinated biphenyls (PCBs) remain an environmental health concern due to their persistence and ongoing release from legacy and emerging sources. 2,2',5,5'-Tetrachlorobiphenyl (PCB52), a PCB congener frequently detected in the environment and human blood, is oxidized to 2,2',5,5'-tetrachlorobiphenyl-4-ol (4-52). The neurotoxicity of this hydroxylated (OH-PCB) metabolite remains poorly characterized. In this study, we exposed 4-week-old male Sprague Dawley rats to 4-52 via a polymeric implant drug delivery system grafted in the subcutaneous cavity at 4-52 concentrations of 0 %, 1 %, 5 %, and 10 % in the implant (w/w) for 28 days. Metabolomic analyses were performed in the serum. RNA sequencing, immunofluorescence, and dopamine (DA) measurement with electrochemical detection were used to characterize the effects of 4-52 on the striatum and cerebellum, brain regions implicated in PCB neurotoxicity. Serum metabolomic analysis revealed disruptions in the "arginine biosynthesis" pathway following 4-52 exposure. Exposure to 4-52 caused moderate transcriptomic changes in pathways related to "oxidative phosphorylation" and "neuroactive ligand-receptor interactions." Immunofluorescence showed no significant alterations in microglial, astrocytic, or apoptotic biomarkers. In the medium dose group, the levels of the DA metabolite DOPAL (3,4-dihydroxyphenylacetaldehyde) were significantly reduced in the striatum. Subsequent multi-omics network analysis identified interactions among OH-PCBs, endogenous metabolites, and the transcriptome. For example, levels of glutamic acid, aspartic acid, choline, and glycerophosphocholine negatively correlated with 4-52 in the striatum. Expression levels of heat shock protein (HSP) family genes, Hsp90b1, Hspa8, and Hspa5, positively correlated with serum metabolites, including proline, 1-methylguanidine, and methionine sulfoxide. These findings identify novel biomarkers and targets of 4-52-induced neurotoxicity.

Epidermal growth factor receptor in placental health and disease: pathways, dysfunction, and chemical disruption

Formation of the placenta during gestation is required to support fetal growth and development. Derived from the placenta, trophoblast cells express nuclear and membrane-bound receptors. Among these receptors is the epidermal growth factor receptor (EGFR) which plays a key role in placental development. Activation of EGFR-mediated signaling in trophoblast cells regulates critical processes, such as proliferation, differentiation, invasion, and fusion during pregnancy, making it essential for normal placental formation. Dysfunction of EGFR in placental trophoblast cells has been associated with adverse pregnancy outcomes, including intrauterine growth restriction, preeclampsia, and preterm birth. Ubiquitous environmental chemicals, like polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, and bisphenols, have been reported to modulate EGFR signaling pathways, potentially contributing to placental dysfunction. This review explores the pivotal role of EGFR signaling in placental development and function, with a focus on how environmental chemicals interfere with EGFR-mediated pathways and placental cell functions as well as their implications for pregnancy outcomes. Findings presented herein underscore the need for further research into the effects of exposure to environmental chemicals on modulating EGFR signaling pathways in the context of placental health.

Environmental Health Is Overlooked in Longevity Research

Aging is a multifactorial process influenced by genetic predisposition and lifestyle choices. Environmental exposures are too often overlooked. Environmental pollutants-ranging from airborne particulate matter and heavy metals to endocrine disruptors and microplastics-accelerate biological aging. Oxidative stress is a major molecular initiating event, driving inflammation and toxicity across biological levels. We detail the mechanisms by which pollutants enhance reactive oxygen species (ROS) production. This oxidative stress inflicts damage on DNA, proteins, and lipids, accelerating telomere shortening, dysregulating autophagy, and ultimately driving epigenetic age acceleration. For instance, exposure to polycyclic aromatic hydrocarbons, benzene, and pesticides has been associated with increased DNA methylation age. Early-life exposures and lifestyle factors such as tobacco and alcohol consumption further contribute to accelerated biological aging. The cumulative loss of healthy life years caused by these factors can conceivably reach between 5 and 10 years per person. Addressing pollutant-induced accelerated aging through regulatory measures, lifestyle changes, and therapeutic interventions is essential to mitigate their detrimental impacts, ultimately extending healthspan and improving quality of life in aging populations.

Uncovering the Potential Link Between Polychlorinated Biphenyls and Cardiovascular Diseases: A Comprehensive Analysis

BACKGROUND

A family of persistent organic pollutants, known as polychlorinated biphenyls (PCBs), are extensively found in the environment and may be harmful to the cardiovascular system. Systematic reviews and meta-analyses are required to thoroughly evaluate the association between PCB exposure and cardiovascular disease (CVDs), despite the fact that studies on the subject have produced inconsistent results.

OBJECTIVE

The purpose of this study was to investigate the relationship between PCBs exposure and cardiovascular disease risk in order to provide more conclusive data to promote public health actions.

METHODS

The studies that met the inclusion criteria were screened out using the databases PubMed, Web of Science, ScienceDirect, and Cochrane Library. The comprehensive effect size (OR) was calculated using the random-effects model; the study's heterogeneity was analyzed using I2 statistics; the major reasons of heterogeneity were identified using subgroup analysis; and publication bias graphically was measured using the Egger's test.

RESULTS

A meta-analysis of 11 studies revealed that total PCBs (OR = 1.56, 95% CI: 1.20-1.75), non-dioxin-like PCBs (NDL-PCBs) (OR = 1.33, 95% CI: 1.15-1.53), and dioxin-like PCBs (DL-PCBs) (OR = 1.31, 95% CI: 1.10-1.57) were all found to be positively associated with the risk of cardiovascular disease. Subgroup analysis revealed that study type, biomaterials, and literature quality were the most significant drivers of variation. Furthermore, certain PCB homologues, such as non-dioxin-like (NDL)-PCB153 and dioxin-like (DL)-PCB118, are highly related with cardiovascular disease.

CONCLUSIONS

According to this meta-analysis, exposure to PCBs may increase the risk of cardiovascular disease. Notwithstanding major drawbacks, our results emphasize the significance of lowering exposure to PCBs and offering a solid theoretical basis for public health initiatives.

Polychlorinated biphenyls and polybrominated diphenyl ethers in infant food: Occurrence and exposure assessment

The objective of this study was to analyze the concentrations of polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in infant food (infant formulas and human milk) collected in Serbia and to assess their exposure and associated health risks. A total of 101 PCB congeners and 26 PBDE congeners were analyzed. In infant formulas (IF), the total PCB levels averaged 63.17 ± 46.67 ng/g fat, with PentaCBs being the most abundant. The highest concentration was observed for PCB #101, at 3.69 ± 2.72 ng/g fat. Total PBDE levels in IF averaged 4.71 ± 2.96 ng/g fat, with DecaBDEs dominating. The highest concentration was determined for BDE #209, at 3.90 ± 2.38 ng/g fat. In human milk (HM), the total PCB levels averaged 82.27 ± 46.70 ng/g fat, with HexaCBs as the predominant group. PCB #153 had the highest concentration, at 12.98 ± 7.91 ng/g fat. Total PBDE levels averaged 4.17 ± 4.55 ng/g fat, with DecaBDEs being most abundant. BDE #209 had the highest concentration, at 3.17 ± 4.01 ng/g fat. The estimated daily intake of dl-PCBs for breastfed and formula-fed infants ranged from 11.79-13.96 to 0.37-0.44 pg WHO2005-PCB-TEQ/kg-bw/day, respectively. Hazard quotients for PBDEs ranged from 1.37-6.50 for breastfed infants to 0.65-5.90 for formula-fed infants, highlighting potential health concerns for breastfed infants. The pollutant levels in HM were comparable to those reported in other Central and Eastern European countries.

Non-dioxin-like polychlorinated biphenyls (NDL-PCBs) dietary exposure is associated with an increased risk of type 2 diabetes in the European prospective investigation into cancer and nutrition (EPIC) cohort

AIMS/HYPOTHESIS

The aim of the present study was to investigate the association between dietary exposures to dioxins, dioxin-like polychlorinated biphenyls (DL-PCBs) and non-dioxin-like polychlorinated biphenyls (NDL-PCBs) and the incidence of type 2 diabetes mellitus (T2DM) in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

This prospective cohort study with a median 11.7 years of follow-up, included 318,416 individuals recruited in 21 centers in eight countries. Dietary intake of dioxins and PCBs was calculated by combining EPIC food consumption data with food contamination data from the European Food Safety Authority (EFSA). To identify incident cases of T2DM, a thorough review of various sources including self-reported information, linkage to primary and secondary care registers, drug registers, hospital admissions, and mortality data was conducted. Associations between dietary intake of dioxins and PCBs and T2DM were evaluated using multivariable Cox regressions.

RESULTS

Higher T2DM risk was observed for higher estimated dietary intake of non-dioxin-like PCBs (NDL-PCBs; HR per 1 SD increment = 1.03 [95 %CI 1.01;1.04], and HR (Q4vs Q1) = 1.15 [1.08;1.22], P-trend < 0.001). The results were consistent in analyses stratified by gender, body mass index, country, median follow-up, or self-reported hypertension and hyperlipidemia, as well as when adjusting for fat intake. No consistent association was observed between dioxins+DL-PCBs intake and T2DM risk.

CONCLUSION / INTERPRETATION

Results obtained in this large European prospective study indicate a positive and linear association between dietary intake of NDL-PCBs and risk of T2DM. This association remained consistent across various stratified and sensitivity analyses. Further studies are warranted to better understand the biological mechanisms underlying this association.

Association between perfluoroalkyl substances and breast cancer on the National Health and Nutrition Examination Survey Database and meta-analysis

The relationship between perfluoroalkyl substances (PFASs) and the risk of breast cancer has been controversial. Here, we used the National Health and Nutrition Examination Survey (NHANES) database and a meta-analysis to examine the association between PFASs and breast cancer incidence. From the NHANES database, we obtained data on PFASs and breast cancer from 2003 to 2014. We searched PubMed, Web of Science, Scopus and PsycINFO from the establishment of the databases to August 24, 2023, for research on PFASs related to breast cancer. A meta-analysis was performed using Stata 12.0. A total of 1430 subjects aged 20 years or older were selected from the NHANES. The logistic regression results indicated that there was no correlation between breast cancer and PFASs (P > 0.05). The meta-analysis, included nine studies with a total of 2399 breast cancer patients, included in the meta-analysis, revealed no statistically significant association between PFASs and the risk of breast cancer (odds ratio = 1.04; 95 % confidence interval, 0.88-1.21; P > 0.05). The results show that PFASs are not associated with breast cancer risk.

Upregulation of fatty acid synthesis genes in the livers of adolescent female rats caused by inhalation exposure to PCB52 (2,2',5,5'-Tetrachlorobiphenyl)

Elevated airborne PCB levels in older schools are concerning due to their health impacts, including cancer, metabolic dysfunction-associated steatotic liver disease (MASLD), cardiovascular issues, neurodevelopmental diseases, and diabetes. During a four-week inhalation exposure to PCB52, an air pollutant commonly found in school environments, adolescent rats exhibited notable presence of PCB52 and its hydroxylated forms in their livers, alongside changes in gene expression. Female rats exhibited more pronounced changes in gene expression compared to males, particularly in fatty acid synthesis genes regulated by the transcription factor SREBP1. In vitro studies with human liver cells showed that the hydroxylated metabolite of PCB52, 4-OH-PCB52, but not the parent compound, upregulated genes involved in fatty acid biosynthesis similar to in vivo exposure. These findings highlight the sex-specific effects of PCB52 exposure on livers, particularly in females, suggesting a potential pathway for increased MASLD susceptibility.