Shaza Gaballah
PhD candidate, Duke University
Integrated Toxicology and Environmental Health Program
She/her
Description: Various legacy environmental contaminants have been shown to accumulate in the maternally- and fetally-derived placenta, including PBDEs (polybrominated diphenyl ethers) and other brominated flame retardants (BFRs), polychlorinated biphenyls (PCBs), organophosphate esters (OPEs), pesticides, phenols, and phthalates. Additionally, some replacement BFRs have been detected in placental tissue, although there is limited research on these emerging contaminants. Research has also demonstrated that certain chemicals, such as PBDEs, may differentially accumulate in the maternal and fetal placenta. Exposure to legacy BFRs in particular has been associated with various adverse health impacts on the fetus, including disruption of thyroid hormones (THs). While many studies have shown that altered fetal TH levels can adversely impact fetal birthweight, growth, cognitive function, and metabolic function, few studies have assessed differences in contaminant and TH levels separately in the maternal and fetal placenta. My research investigates maternal and fetal placental levels of legacy and emerging contaminants and THs, and assesses associations between contaminants, THs, placental tissue (i.e. maternal or fetal placenta), and fetal sex. In order to more directly assess how in utero PBDE exposure impacts PBDE accumulation and TH levels during later gestation in the two placental compartments, we conducted a controlled dosing study in pregnant Wistar rats. Next, we analyzed term human placental tissue for a suite of legacy and emerging contaminants and for THs to assess patterns of placental accumulation by tissue and sex, as well as associations between contaminant and TH levels. Finally, we assessed whether factors such as maternal age, birthweight, and gestational age are associated with maternal or fetal placental levels of contaminants and THs. This work highlights the benefits of analyzing contaminants and hormones in the placenta as an indicator of fetal exposure, the impacts of placental morphology on PBDE accumulation across gestation, as well as trends in the fetal and maternal placental accumulation of both legacy and emerging replacement flame retardants and their associations with placental TH levels.
About the speaker: Shaza is a 6th year PhD Candidate in the Integrated Toxicology and Environmental Health Program at Duke University working in Dr. Heather Stapleton’s lab. After completing a B.S. in Biology at UNC Chapel Hill in 2017, Shaza became interested in exploring toxicology and (on a whim) applied for a fellowship at the US EPA in Dr. Tamara Tal’s lab. Her work there assessed how exposure to GenX and other per- and polyfluoroalkyl substances (PFAS) impacts developmental toxicity and developmental neurotoxicity in zebrafish, and identified shared toxicity phenotypes in zebrafish based on varying PFAS chemical structures. Following her fellowship, Shaza decided to pursue environmental toxicology and applied to ITEHP. Since joining Duke, Shaza’s research has focused on assessing in utero exposure to brominated flame retardants and other environmental contaminants in the placenta and understanding how these gestational exposures may impact TH homeostasis during a critical window of fetal development.
Friday, December 6, 2024, 12:00-1:15pm Eastern
Field Auditorium, Room 1112, Grainger Hall (9 Circuit Drive, Durham, NC)
This seminar will also be presented live via Panopto. Click HERE for the livestream.