Prenatal Exposure to Per- and Polyfluoroalkyl Substances (PFASs) and Association between the Placental Transfer Efficiencies and Dissociation Constant of Serum Proteins-PFAS Complexes
By Ke Gao, Taifeng Zhuang, Xian Liu, Jianjie Fu, Jingxing Zhang, Jie Fu, Liguo Wang, Aiqian Zhang, Yong Liang, Maoyong Song, and Guibin Jiang
Environ. Sci. Technol.
May 17, 2019
Information on placental transfer and adverse outcomes of short-chain per- and polyfluoroalkyl substance (PFASs) is limited, and factors responsible for PFAS placental transfer are still unclear. In the present study, concentrations of 21 PFASs were analyzed in 132 paired maternal and cord serum samples collected from Beijing, China, and placental transfer efficiency (PTE) of each PFAS was calculated. PTEs of short-chain perfluoroalkyl acids (PFAAs), including PFBA (146%), PFBS (97%), PFPeA (118%) and PFHxA (110%), were firstly reported, and a complete U-shape trend of PTEs from C4 to C13 of perfluoroalkyl carboxylic acids (PFCAs) were obtained. Positive association between maternal weight and PTE of perfluorooctane sulfonate (PFOS) (p<0.05), and negative association between maternal PFBA concentration and birth length (p<0.01) were observed. Using in vitro experiments, we further determined equilibrium dissociation constants (Ks) of human serum albumin (HSA)-PFAS complexes (K), serum proteins-PFAS complexes (K) and liver-fatty acid binding protein (L-FABP)-PFAS complexes (K), and found that they were all significantly correlated with PTEs of PFASs. The correlation coefficient was 0.92, 0.89, and 0.86, respectively (p<0.01 in all three tests), suggesting that Ks of protein (serum)-PFAS complexes can play an important role in trans-placental transfer of PFASs in human, and K, plays a pivotal role.