Cerebrovascular pathology in db/AD mice. SEM images of vascular casts from brains of 4 mice (a-d). (a) Relatively normal appearing cerebrovasculature of a WT mouse (large vessel is a small artery; note the clear endothelial cell nuclear imprints and their elongated shapes). (b) Aneurysm (arrow) in the brain of an AD mouse near a large vein. Some of the AD mice exhibited more severe cerebrovascular pathology, possibly representing clusters of saccular aneurysms (c) or arterial blebbing (d). In comparison, WT and db mice had minimal pathology at this age. (e - f) Prussian blue (with neutral red counterstain) staining showing microhemorrhages in two different cortical areas in older db/AD mice.