AQP4 and Stroke: CD astrocytes in the frontal white matter of post‐stroke demented (PSD) subjects occur at higher frequencies compared to post‐stroke individuals without dementia (PSND), with a loss of aquaporin 4 (AQP4) and white matter pericytes, suggesting that changes in astrocytic function and disruption of the gliovascular unit at the BBB contribute to dementia after stroke (40, 41).