Development of a Novel, Physiologically Realistic Pediatric Blood Brain Barrier on a Chip

Abstract

Currently, there is a lack of a good experimental in vitro model for mimicking the blood brain barrier (BBB) to study the mechanisms of BBB permeability and to screen brain-penetrating therapeutics. We have developed a physiologically realistic in vitro pediatric BBB model on a chip (B3C) using an optically clear, oxygen permeable polymer, polydimethysiloxane (PDMS) on a glass slide that includes the vascular (apical) and tissue (basolateral) compartments. Brain cells, e.g., astrocytes, contribute to the BBB phenotype. To model the BBB and compare BBB permeability, we cultured rat brain endothelial cells (RBEC) from pediatric and adult rats in the vascular compartment of the device under static or flow conditions in the presence or absence of astrocyte conditioned media (ACM). The barrier formation by RBEC in B3C was assessed by immunofluorescence staining of RBEC for tight junction molecules [e.g. zonula occludens-1 (ZO-1)] and by measuring transendothelial electrical resistance (TEER) and permeability of fluorescently tagged molecules (e.g. Texas Red-Dextran) across the barrier formed by RBEC. In B3C, pediatric RBEC exhibited higher permeability and a lower expression of tight junction molecules (e.g. ZO-1) compared to adult RBEC; this barrier was further strengthened by the presence of flow and the addition of ACM. This physiologically realistic pediatric BBB model (B3C) can be used to study BBB function in pediatric neurological diseases and to test novel therapeutics for these diseases.