Development and functional characterization of complex in vitro models of the blood-brain barrier

Abstract

The blood–brain barrier (BBB) is a specialized structure that protects the brain but also makes it difficult for many drugs to reach the central nervous system. To better understand how the BBB works and to develop ways to deliver treatments to the brain, researchers need reliable lab-based models that closely mimic how the barrier functions in the human body. This dissertation focuses on developing, characterizing and functionally testing in-vitro models of the BBB using a combination of primary cells and cells derived from stem cells. The models include co-cultures of brain endothelial cells, astrocytes, and pericytes, which are important components of the neurovascular unit (NVU). A major part of the work involved developing a microfluidic chip-based model that allows the endothelial cells to grow under flow, simulating blood flow in the brain. The model was tested for how well it could mimic natural barrier properties, including integrity, transport functions, and small molecule permeability. Compared to traditional methods, the new model showed better accuracy and could more reliably predict how drugs might behave in the human brain. We also tested our models ability to support studies on Central Nervous System (CNS) targeted therapeutic delivery via receptor- mediated transcytosis. Overall, this work presents functional and translationally relevant BBB models that can be used to study brain diseases and test potential new treatments in the lab before moving to animal or human studies.