ACTA1 and Alzheimer disease: The CAA-independent but Braak stage-dependent α-SMA loss in both artery types from Braak stage II/III onward we observed was supported by previous findings of CAA-independent vascular smooth muscle loss in the posterior cerebral artery in AD [49], and was different from the CAA dependence of the arteriolar/microvascular α-SMA loss we and others [17, 54, 55] had found.