To clarify the immunohistochemical features
of amyloid deposits and cerebral amyloid angiopathy
(CAA), the distribution of the amyloid ß-protein
subtypes Aß40, Aß42, Aß43 and Aß precursor protein
(APP) were examined in the brains of fourteen aged cats
(7.5-21 year-old). Two types of plaques were detected.
The first type was characterized by Aß positive antigenic
material and detected in the cortical layers of the frontal
and parietal lobes of all examined cats. The second type
was characterized by diffuse positive immune staining
representing diffuse plaques, which were detected only
in the very aged cats (17-21 years old) and distributed
throughout the cortical layers of the parietal lobes.
Vascular amyloid and the amyloid deposits were
strongly positive-stained with the antibody Aß42. APP
was exhibited in neurons and axons while the staining
was stronger in the very aged cats (17-21 years old). Our
findings suggest that the feline forms a spontaneous
model for understanding the early changes of normal
brain aging and the early stage of amyloid ‚-protein
deposition