Blogs

The placenta is a very unique organ, responsible for ensuring the healthy development of fetuses early in life. However, we still know very little about this organ despite its importance. During the 2021 SOT Annual Meeting and ToxExpo Symposium Session titled “Environmental Influences on Placental Origins of Development,” several researchers highlighted how they are studying the placenta and its role in environmental exposure and developmental toxicity.

Dr. Thad Schug from the National Institute of Environmental Health Sciences started the session with an introduction on the placenta. The placenta is the intermediary between mother and fetus throughout pregnancy and is necessary for the transport of nutrients, waste, and environmental chemicals. Dr. Schug spoke about the Environmental Influences on Placental Origins of Development (ePOD) program and its aim to develop better models of understanding placental exposures. The ePOD program has funded several studies to look at placental responses to environmental chemicals such as cadmium, pyrethroids, phthalates, polychlorinated biphenyls, and metal mixtures.

Dr. Phoebe Stapleton from Rutgers, The State University of New Jersey, described research from her lab on the impact of inhaled nanoplastics in a maternal-fetal model. Rats were exposed to nanoplastic particles through the maternal lung, and nanoplastics were later found to accumulate in both the placenta and the offspring, indicating that the nanoplastics were transported from the maternal lung to the fetal compartment. Expanding on this, her lab used placental perfusion techniques to collect effluent from the uterine artery and the fetal umbilical vein. This effluent showed that nanoplastics crossed from the uterine artery to the umbilical vein within three hours of maternal exposure. Dr. Stapleton also described how maternal nanoplastic exposure altered fetal growth, noting a decrease in pup weight and placental weight in exposed animals.

Dr. Joshua Robinson from the University of California San Francisco presented work from placental cell culture experiments. Cytotrophoblasts (CTBs) are important cells for forming the barrier between the maternal and fetal blood supply, and using primary human villous CTBs in culture is a way to explore placental development and function. When these CTBs are exposed to flame retardants such as organophosphate flame retardants (OPFRs) and polybrominated diphenyl ethers (PBDEs), flame retardants accumulate in the cells and cytotoxicity occurs. Further, PBDEs inhibit the migration and invasion of the CTBs. Since invasion of CTBs is an important step for normal human placental development, inhibition of this invasion has implications for disrupting placental function. Dr. Robinson also showed how transcriptomic analyses with CTBs were used to understand that flame retardants could alter genes involved with endocrine function and pregnancy complications.

Lastly, Dr. Kristin Bircsak from MIMETAS described the development of a high-throughput placenta-on-a-chip model. She described how placenta-on-a-chip cultures could express MRP efflux transporter mRNA and how MRP-mediated transport can be inhibited in the model.

It’s exciting to see how SOT members and other investigators are currently using in vitro, in vivo, ex vivo, and placenta-on-a-chip models to better understand the placenta and to appreciate the placenta’s role in early-life exposures. This placental research certainly helps us in elucidating how environmental exposures can cause placental toxicity or alter later development and health in mother and baby.

This blog was prepared by an SOT Reporter and represents the views of the author. SOT Reporters are SOT members who volunteer to write about sessions and events in which they participate during the SOT Annual Meeting and ToxExpo. SOT does not propose or endorse any position by posting this article. If you are interested in participating in the SOT Reporter program in the future, please email Giuliana Macaluso.

Sessions delivered during the 2021 SOT Annual Meeting and ToxExpo will be available on the Virtual Meeting Platform on demand to registrants through May 31, 2021.