An analysis of AD and intramural hematoma samples from patients undergoing surgical treatment revealed that the CD31 expression was lost by the M1 macrophages that densely penetrated into the acute aortic wall lesion sites, with CD31 re-expression accompanied the appearance of M2 and the disappearance of M1 macrophages at the valid aortic wall healing sites (Fornasa et al., 2012; Andreata et al., 2018). Here, PECAM1 is linked to Alzheimer disease.