P1‐292: Analysis of Aβ transport in a human blood‐brain barrier model

The blood-brain barrier physiologically separates the brain from the circulation and is made up of highly specialized endothelial cells. Tight junctions make passive transcytosis almost obsolete. Consequently receptor mediated transport across the barrier is of high importance. Both Alzheimer Disease (AD) and Cerebral Amyloid Angiopathy (CAA) are characterized by accumulation of Aβ. For most sporadic cases this can be attributed to a decreased clearance of Aβ due to reduced transport across the blood-brain barrier. However, the exact role of various receptors involved in Aβ transport across this barrier and components that may affect this process has not yet been fully determined. Recently the hCMEC/D3 cell line was characterized as a valid model for the blood-brain barrier. In this study we aim to use this model to characterize the transport of Aβ across the blood-brain barrier in AD and CAA. Endothelial hCMEC/D3 cells were cultured in transwell inserts. Cells form a confluent monolayer with blood brain barrier characteristics as described in literature and trans-endothelial electrical resistance (TEER) was measured using the Millicell-ERS system to indicate membrane integrity, and to validate the model. Cells were cultured in the presence of Aβ for 24h. Uptake of Aβ and transport of Aβ across the barrier was determined by ELISA, SDS-PAGE and western blotting. We have developed and validated an endothelial cell model to analyze transport of Aβ across the blood-brain barrier. We will present the first results on uptake and transport characterization of different Aβ isoforms using this model. With the first characterization of the model we will now focus on determining the role of several receptors expressed on the blood-brain barrier, and of amyloid-binding proteins such as APOE in Aβ clearance.