The integrity of the dural lymphatic system, likely assisted by the water channel aquaporin 4 [87], seems to play a key role in clearance of extracellular tau and Aβ [88], as well as the importance of the BBB and endothelial function in the movement of tau from brain to blood [89], and possible effects of cardiovascular risk factors, trauma, or cerebrovascular pathology in AD development [90]. This evidence concerns the gene MAPT and Alzheimer disease.