In Vitro Models of the BloodCerebrospinal Fluid Barrier and Their Use in Neurotoxicological Research

The choroid plexus epithelium forms the interface between the blood and the cerebrospinal fluid. In addition to its barrier function resulting from the presence of tight junctions sealing the epithelial cells together, the choroid plexus epithelium fulfills vectorial transport (influx and efflux), neuroprotective, antioxidant and secretory functions, all relevant to different aspects of neurotoxicological sciences. To investigate these choroidal functions without the interference of the blood–brain barrier proper and brain parenchyma, in vitro cellular models of the blood–cerebrospinal fluid barrier, retaining the differentiated phenotype of the choroidal epithelium, have been established, taking advantage of the advent of refined culture methods and availability of permeable membranes. This chapter provides information to help investigators to set up and characterize choroid plexus epithelial cells in culture in bicameral devices. It first describes the factors that are critical to isolate the cells and select the culture conditions, and provides a survey of available cell lines with their advantages and limitations. Then the primordial specific choroidal features that can be examined within a validation scheme are discussed, emphasizing the need for a careful interpretation of their significance. In a third part, selected examples of studies performed with these models are presented, highlighting their potential applications in the field of neurotoxicology.