Vascular smooth muscle cells may synthesize A-beta protein.
Alternate hypotheses are the A-beta derives from the brain or systemic blood.
CAA with DBL in nondemented persons is most often seen in surgical biopsies of persons operated upon to control spontaneous intracerebral bleeding. The outer layer is most heavily affected. It is likely the clear halo is an artifact caused by differential shrinkage of amyloid-laden and unaffected segments of the vascular wall. Less commonly, there is more extensive intimal proliferation or concomitant atherosclerosis. Some vessels with DBL morphology are A-beta negative.