2003). Indeed, hiPSC-derived astrocytes highly expressed GDNF, bFGF, EGF (epidermal growth factor), and Ang1 (Figure S6D). Further analyses are needed to identify the BBB maturation factors from hiPSC-derived astrocytes. In addition, previous anatomical examination of the brain microvasculature showed that the endfeet of astrocytes form a lacework of fine lamellae to closely support the outer surfaces of the endothelium (Kacem et al., 1998). Although we successfully used Transwell dishes, which separate the apical and basolateral sides, to analyze drug kinetics, the construction of a three-dimensional BBB model from all four cell populations will expedite mature BBB formation and BBB physiology analysis.
