Degeneration of cortical neurons associated with diffuse β‐amyloid (Aβ) deposits in Alzheimer's disease

Abstract

The frequency of morphological abnormalities in neuronal perikarya which were in contact with diffuses β-amyloid (Aβ) deposits in patients with Alzheimer's disease (AD) was compared with neurons located adjacent to the deposits. Morphological abnormalities were also studied in elderly, non-demented (ND) cases with and without diffuse Aβ deposits. In AD and ND cases with Aβ deposits, an increased proportion of neurons in contact with diffuse deposits exhibited at least one abnormality compared with neurons located adjacent to the deposits. Neurons in contact with diffuse deposits exhibited a greater frequency of abnormalities of shape, nuclei, nissl substance and had a higher frequency of cytoplasmic vacuoles compared with adjacent neurons. A greater frequency of abnormalities of shape, nissl substance and in the frequency of displaced nuclei were also observed in neurons adjacent to diffuse deposits in AD compared with the ND cases. With the exception of absent nuclei, morphological abnormalities adjacent to diffuse deposits in ND cases were similar to those of ND cases without Aβ deposits. These results suggest that neuronal degeneration is associated with the earliest stages of Aβ deposit formation and is not specifically related to the formation of mature senile plaques.