Briefly, endothelial cells derived from pluripotent stem cells (brain like endothelial cells obtained and handled following EU Directive 2004/23/EC) and bovine pericytes were defrosted in gelatincoated Petri dishes (Corning). Pericytes were cultured in DMEM pH 6.8 while endothelial cells were cultured in supplemented endothelial cell growth medium (sECM) (ScienCell). After 48 h, endothelial cells were seeded in 0.4 μm polycarbonate 12-well Transwell inserts (8,000 cell/well) and pericytes were plated in 12-well plates (50,000 cells/well) previously coated with Matrigel and gelatin, respectively. The medium was changed every 2-3 days and the assays were performed 7-8 days after seeding by placing the transwells into new wells without pericytes.