Placental cellular composition and umbilical cord tissue metal(loid) concentrations: A descriptive molecular epidemiology study leveraging DNA methylation

Morphological and cellular effects of lead, cadmium, and perfluorooctanoic acid on Gallus gallus embryonic development: Insights into cephalic region vulnerabilities

Lead (Pb), cadmium (Cd), and perfluorooctanoic acid (PFOA) are environmental pollutants with bioaccumulative properties, posing risks to embryonic development, particularly through cephalic region malformations. Despite their significance, few studies have investigated their effects at realistic concentrations or in mixtures. This study assessed the individual and combined effects of Pb, Cd, and PFOA on Gallus gallus embryos at relevant concentrations, focusing on the cephalic region at stages HH10 and HH14. Exposure to contaminant mixtures, particularly Pb + Cd, Pb + PFOA, and the full combination, resulted in a higher incidence of cranial malformations compared to single-compound exposures. Cd induced dose-dependent changes in cell morphology and significantly reduced proliferation in the head region. PFOA contributed additively to mixture toxicity, markedly impairing cell proliferation and modifying the expression of key adhesion molecules such as β-catenin and N-cadherin. Both embryonic stages exhibited aberrant cellular delamination from the neural tube, with HH10 embryos displaying heightened vulnerability. Systems biology analysis revealed distinct molecular responses to each contaminant, with Pb and Cd primarily affecting immune-related pathways, including complement activation, while PFOA operated through separate regulatory mechanisms. Integrative network analyses using STITCH 5 and the Comparative Toxicogenomics Database identified candidate genes potentially involved in developmental disruption. These findings underscore the complex interactions between pollutants, which may not be predicted solely by examining individual exposures and highlight the need for stricter environmental regulations to address the risks posed by contaminant mixtures.

Prenatal Exposure to Metals Is Associated with Placental Decelerated Epigenetic Gestational Age in a Sex-Dependent Manner in Infants Born Extremely Preterm

Prenatal exposure to metals can influence fetal programming via DNA methylation and has been linked to adverse birth outcomes and long-term consequences. Epigenetic clocks estimate the biological age of a given tissue based on DNA methylation and are potential health biomarkers. This study leveraged the Extremely Low Gestational Age Newborn (ELGAN) study (n = 265) to evaluate associations between umbilical cord tissue concentrations of 11 metals as single exposures as well as mixtures in relation to (1) placental epigenetic gestational age acceleration (eGAA) and the (2) methylation status of the Robust Placental Clock (RPC) CpGs. Linear mixed effect regression models were stratified by infant sex. Both copper (Cu) and manganese (Mn) were significantly associated with a decelerated placental eGA of -0.98 (95% confidence interval (CI): -1.89, -0.07) and -0.90 weeks (95% CI: -1.78, -0.01), respectively, in male infants. Cu and Mn levels were also associated with methylation at RPC CpGs within genes related to processes including energy homeostasis and inflammatory response in placenta. Overall, these findings suggest that prenatal exposures to Cu and Mn impact placental eGAA in a sex-dependent manner in ELGANs, and future work could examine eGAA as a potential mechanism mediating in utero metal exposures and later life consequences.