INTRAARTERIAL INFUSION OF [I-125] A-BETA-1-40 LABELS AMYLOID DEPOSITSIN THE AGED PRIMATE BRAIN IN-VIVO

ALZHEIMER'S disease is characterized by extracellular amyloid deposits in the brain at both vascular sites (cerebrovascular amyloid, CVA) an d within the neuropil (plaques). In the present study we demonstrated that brain amyloid of aged non-human primates is efficiently detected by [I-125]A beta in vitro, and assessed the detection of that amyloid in vivo by intravascular infusion of [I-125]A beta. Aged squirrel monk eys (Saimiri sciureus) were anesthetized and infused intra-arterially with [I-125]A beta, and sacrificed 2 h later. Analysis of the anterior frontal and temporal cortices by autoradiography demonstrated that [I -125]A beta was deposited on CVA and that essentially every amyloid de posit which could be detected with thioflavin S or anti-A beta antibod ies was also labeled by [I-125]A beta. These experiments suggest that intravascular infusion of radiolabeled A beta can be used to detect an d image amyloid deposits in the human AD brain.