Amyloid β precursor protein-mRNA is expressed throughout cerebral vessel walls

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