MAPT and Alzheimer disease: A recent study using a CSF biomarker of BBB-associated capillary mural cell pericytes, and which examined the regional BBB permeability using dynamic MRI, showed that patients with AD have BBB disruption combined with cerebral SVD in the hippocampus, regardless of cerebral Aβ plaque and pathologic tau, suggesting that BBB disruption is an early biomarker for AD (97).