Journal Article

Influence of Prenatal Lead Exposure on Genomic Methylation of Cord Blood DNA

Wright, Robert O., Mercado-García, Adriana, Ettinger, Adrienne, Lamadrid-Figueroa, Héctor, Téllez-Rojo, Martha Maria, Sánchez, Brisa N., Cantonwine, David, Lazarus, Alicia, Pilsner, J. Richard, Hernández-Avila, Mauricio, Hu, Howard

2009

Overview

Background: Fetal lead exposure is associated with adverse pregnancy outcomes and developmental and cognitive déficits; however, the mechanism(s) by which lead-induced toxicity occurs remains unknown. Epigenetic fetal programming via DNA methylation may provide a pathway by which environmental lead exposure can influence disease susceptibility. Objective: This study was designed to determine whether prenatal lead exposure is associated with alterations in genomic methylation of leukocyte DNA levels from umbilical cord samples. Methods: We measured genomic DNA methylation, as assessed by Alu and LINE-1 (long interspersed nuclear element-1) methylation via pyrosequencing, on 103 umbilical cord blood samples from the biorepository of the Early Life Exposures in Mexico to Environmental Toxicants (ELEMENT) study group. Prenatal lead exposure had been assessed by measuring maternal bone lead levels at the mid-tibial shaft and the patella using a spot-source ¹⁰⁹Cd K-shell X-ray fluorescence instrument. Results: We found an inverse dose-response relationship in which quartiles of patella lead correlated with cord LINE-1 methylation (p for trend = 0.01) and and tibia lead correlated with Alu methylation (p for trend = 0.05). In mixed effects regression models, maternal tibia lead was negatively associated with umbilical cord genomic DNA methylation of Alu (β = -0.027; p -0.01). We found no associations between cord blood lead and cord genomic DNA methylation. Conclusions: Prenatal lead exposure is inversely associated with genomic DNA methylation in cord blood. These data suggest that the epigenome of the developing fetus can be influenced by maternal cumulative lead burden, which may influence long-term epigenetic programming and disease susceptibility throughout the life course.

• Publisher: National Institute of Environmental Health Sciences
• Subject: Base Sequence / Blood / Blood levels / Bones / Chemical hazards / Children's Health / Complications and side effects / Cord blood / Deoxyribonucleic acid / DNA / DNA Methylation - drug effects / DNA Primers / Environmental health / Environmental Pollutants - toxicity / Epigenetics / Exposure / Female / Fetal Blood - metabolism / Genomics / Health aspects / Humans / Lead / Lead - toxicity / Maternal Exposure / Methylation / Mexico / Physiological aspects / Polymerase Chain Reaction / Pregnant women / Toxicants / X-ray fluorescence