The amyloid beta-protein precursor is localized in smooth muscle cells of leptomeningeal vessels.

We examined leptomeningeal vessels using 2 different antisera which recognized both terminal ends of amyloid beta-protein precursor (APP). Both antisera recognized a 120-kDa protein from leptomeningeal vessels. Immunocytochemistry showed that APP was localized in the smooth muscle cells of leptomeningeal vessels. These results indicated that the smooth muscle cells of leptomeningeal vessels contained full-length native APP, and that the cerebrovascular amyloid in the leptomeningeal vessels was derived from this APP.