Amyloid beta precursor protein-mRNA is expressed throughout cerebral vessel walls.

To determine the presence and distribution of cerebrovascular Abeta production we investigated amyloid beta precursor protein (AbetaPP)-mRNA expression by RNA in situ hybridization in patients with hereditary cerebral hemorrhage with amyloidosis, Dutch type, Alzheimer disease and controls. In all subjects, AbetaPP-mRNA was expressed in endothelial cells, smooth muscle cells, adventitial cells and brain pericytes and/or perivascular cells. Meningeal cells also expressed AbetaPP-mRNA. AbetaPP was detected in endothelial cells, smooth muscle cells and adventitial cells. The demonstration of AbetaPP-mRNA at all vascular sites where amyloid formation can occur supports an important contribution of locally derived Abeta to cerebrovascular amyloidosis.