Figure 1.

Thioflavin-S–stained whole-mounted tufts of cortical vessels after complete brain parenchyma lysis by EDTA-SDS. A: Ring-like amyloid deposits in leptomeningeal arterial walls. The pattern of deposition follows the orientation of the smooth muscle cells. Magnification 25×. B: Tufts of cortical-penetrating arteries heavily loaded with amyloid from an AD patient with Apo E ɛ4/ɛ4 genotype. The perivascular spaces are probably occluded in the saturated amyloid vessels, and in some cases may be totally destroyed by the encroaching amyloid, thus hindering the elimination of interstitial fluid. Magnification 100×. C: Cortical arterioles and capillaries showing an abundant deposition of amyloid cores, in an individual with Apo E ɛ4/ɛ4 genotype, at different stages of development that are intimately linked to the basal laminae of the vessels. The profuse deposits of amyloid at the arteriolar/capillary junction may block the openings of the perivascular spaces that drain the brain’s interstitial fluid. Magnification 200×. D: At a higher magnification, each of the fluorescent blebs represents a fully developed globular deposit of amyloid evenly spread around and constricting the microvessel, probably creating areas of ischemia and alterations in blood-brain barrier. Magnification 400×.