To investigate temporal changes in BBB integrity and the correlation of BBB disturbances with microglial responses in chronic hypertension, we examined isolated fragments of microvessels and found a significant downregulation of the two critical tight junction molecules claudin-5 (Cldn5) and occludin (Ocln) in early hypertension (Fig. 6b, c). Here, CLDN5 is linked to hypertensive disorder.