(926) A fetal blood-brain-barrier microphysiological system to study the effect of in-utero toxicant exposure

Friday, January 31, 2025

10:30 AM – 12:30 PM

Submitting Author and Presenting Author(s)

SS

Sourabh Sharma, MD

Maternal Fetal Medicine Fellow
University of Texas Medical Branch Galveston
Galveston, Texas, United States

Coauthor(s)

Lauren Richardson, PhD

Assistant professor
University of Texas Medical Branch
Galveston, Texas, United States
Ramkumar Menon, PhD

Director
University of Texas Medical Branch
Galveston, Texas, United States

Objective: Glutamate dysregulation resuling in neuronal damage is associated with the development of many neurological disorders. The lack of physiologically relevant in-vitro models has limited our mechanistic understanding. This study evaluated the effect of environmental pollutant Polybrominated Diphenyl Ethers (PBDE), using a microphysiologic (MPS) model of human fetal blood-brain-barrier (FB).

Study Design: The FB-OOC is composed of 3-cell culture chambers, connected by microchannels, containing 1)brain microvessel endothelial cells, 2)human vascular pericytes, and 3)a triculture of neurons, astrocytes, and microglia in a 5:2:1 ratio, respectively. To assess the effect of toxicants on glutamate dysregulation and neuroinflammation, endothelial cells were exposed to PBDE(150ng/ml). To mimic the passage of PBDE through the placenta, endothelial cells were exposed to conditioned PDBE media from a placenta-OOC (1:1). In parallel, triculture cells were directly treated in a 96-well plate. Dextran propagation over 72 hours and zonula occludens-1 expression confirmed FB barrier function. Cell morphology (microscopy), cell cytotoxicity, and cytokines were measured. Statistical significance was determined by unpaired t-tests (N=5; p< 0.05).

Results: Control FB-OOC were characterized by 1)viable cell cultures expressing standard cell morphologies and cell-specific markers, 2)barrier formation confirmed by lack of dextran propagation over 72 hours, and 3) baseline pro-inflammatory cytokines. On-chip PBDE and placenta-derived metabolites of PBDE treatment in the endothelial chamber induced cell cytotoxicity and upregulation of glutamate in the triculture but did not induce neuroinflammation. Conversely, 2D triculture experiments showed direct PBDE treatment-induced neuroinflammation compared to PBDE placenta-derived metabolites or controls.

Conclusion: This study established a model of FB that assessed the role of glutamate dysregulation independent of neuroinflammation. Advanced MPS models are needed to evaluate the impact of various exposures at the FB, as 2D neuronal cultures cannot model intercellular interactions.