Jennifer J. Adibi, Sc.D.
University of Pittsburgh
A new study, funded in part by NIEHS, used human cells to study previously observed relationships between prenatal exposure to phthalates and gene expression essential to placental function. The study provides insight into the molecular basis by which phthalates may alter the function of the placenta.
Researchers have observed links between maternal phthalate exposure and problems during birth and with the health of the child. Studies in animal models and in nonplacental tissue suggested that those links may be associated with effects on placental function. To directly study the effects of phthalates on the human placenta, the scientists used placental cells anonymously donated by women undergoing elective pregnancy terminations. The cells were cultured with metabolites for mono-n-butyl (MnBP), monobenzyl (MBzP), mono-2-ethylhexyl (MEHP), and monoethyl (MEP) phthalates and a mixture of the phthalate metabolites. They used metabolite concentrations representing levels previously measured in pregnant women.
Using the human placental cells, the researchers observed that exposure to MnBP, MBzP, and MEHP affected expression of genes essential to placental function in ways previously observed in other studies. Phthalate exposure was also associated with differences in levels of hCG and PPARγ, proteins expressed by the affected genes. In some cases, the researchers saw marked, even opposite, differences in hCG protein expression depending on the sex of the cells. The researchers say that these sex differences may be partially regulated by PPARγ, a hypothesis that could be further tested to better understand why the hormonal effects of phthalates affect males and females in opposite ways.
Citation: Adibi JJ, Zhao Y, Zhan LV, Kapidzic M, Larocque N, Koistinen H, Huhtaniemi IT, Stenman UH. 2017. An investigation of the single and combined phthalate metabolite effects on human chorionic gonadotropin expression in placental cells. Environ Health Perspect. 125(10):107010.