Blood–Brain Barrier In Vitro Models and Their Applications in Toxicology

Located at the level of brain capillaries, the blood–brain barrier (BBB) is a crucial component of the neurovascular unit, since its highly regulated properties are needed to maintain optimal conditions for proper neuronal and glial functions. By modelling the BBB it is possible to make predictions about whether a compound's interaction with the BBB is likely to compromise its functionality. A dysfunctional BBB may either affect brain entry of an agent or indirectly generate unwanted effects on neurons and glial cells by disturbing the brain homeostasis. Since the BBB controls the exchanges between the blood and brain compartments modelling the BBB in vitro can also help to investigate the ability of compounds to cross the BBB. In this chapter, the plethora of in vitro BBB models that exist today is discussed and several methods needed to set up and use of these in vitro models in the framework of in vitro toxicity study is detailed.