APP and Alzheimer disease: In this study, we hypothesize that the major contribution of atherosclerosis to AD is via its effects on blood coagulation and chronic formation of platelet micro-clots, which sequester and enrich numerous activated platelets, thus allowing a massive release of Aβ peptides (directly, or cleaved from released APP) and the conversion of soluble Aβ40 into fibrillar Aβ aggregates at the surface of platelet micro-clots.