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Your Environment. Your Health.

Serotonin Changes Linked to Flame Retardants in Placenta

Heather Patisaul, Ph.D.
North Carolina State University
R56ES022957, P30ES025128, T32ES021432, R01ES016099

NIEHS grantees showed a connection between exposure to a flame retardant chemical mixture and disruption of normal placental function in rats, which led to altered production of the neurotransmitter serotonin. Flame retardant exposure was associated with effects related to inflammation, hormones, and neurodevelopment. Some of the effects were only observed in female offspring.

The researchers exposed pregnant rats to the chemical FireMaster 550 (FM 550), a flame-retardant mixture used in foam-based baby products and furniture. The team examined the placentas and developing brains of the offspring to identify possible pathways affected by the chemical mixture. The dose levels used were all below the 50 milligrams per day currently considered safe.

In female offspring, the researchers found increased levels of estrogen and androgen receptors in placentas with exposure. They also observed an altered ratio of serotonin and its metabolite 5-HIAA in placentas and fetal forebrains of female offspring compared with the unexposed group. This finding demonstrated disruption of neurotransmitter production in the placenta and developing brain. Increased markers of inflammation that are associated with elevated risk of behavioral disorders were observed in placentas from both sexes.

According to the authors, these findings demonstrate that environmental contaminants like FM 550 have the potential to affect the developing brain by disrupting normal placental functions. These data also show, for the first time, that flame retardants can have sex-specific effects on placental functions critical for brain development.

Citation: Rock KD, Horman B, Phillips AL, McRitchie SL, Watson S, Deese-Spruill J, Jima D, Sumner S, Stapleton HM, Patisaul HB. 2018. EDC IMPACT: Molecular effects of developmental FM 550 exposure in Wistar rat placenta and fetal forebrain. Endocr Connect 7(2):305–324.

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