PAH Exposure, Methylation, & Adducts in Cord Blood

NEW YORK (Janurary 17, 2012)-  There is a complex relationship between prenatal exposure to polycyclic aromatic hydrocarbons, benzo[a]pyrene-DNA adducts and genomic DNA methylation in the cord blood of newborns. Researchers, led by Dr. Julie Herbstman, from the Columbia Center for Children’s Environmental Health (The Center) set out to investigate whether an increase in prenatal exposure to air pollution impacts the delicate process of DNA methylation in the womb.

The Center recently published, “Prenatal Exposure to Polycyclic Aromatic Hydrocarbons, Benzo[a]Pyrene-DNA Adducts and Genomic DNA Methylation in Cord Blood,” which highlights the association between PAH exposure during pregnancy and a decrease in DNA methylation in umbilical cord blood. Early embryonic development may be a particularly susceptible period for PAH exposure resulting in both increased PAH-DNA adducts and altered DNA methylation. DNA methylation is a biochemical process that is crucial for normal development, cellular differentiation, and gene expression. Both increases in DNA methylation (hypermethylation) at specific genes and decreases in DNA methylation (hypomethylation) overall have been associated with cancer and other diseases in humans.

The observations from the study suggest that PAH exposure in the study population (Northern Manhattan and South Bronx residents) was adequate to reduce global methylation levels, which is an indicator of genomic instability. Additional epidemiologic studies that can measure site-specific DNA methylation and adduct formation will improve our ability to understand this complex molecular pathway.

This study was published in the journal of Environmental Health Perspectives online January 17, 2012 and will be released in an upcoming print issue.

The authors include Julie B. Herbstman, Deliang Tang, Deguang Zhu, Lirong Qu, Andreas Sjödin, Zheng Li, David Camann, and Frederica P. Perera.