The relationship between alpha B-crystallin and neurofibrillary tangles inAlzheimer's disease

alphaB-crystallin is known as a small heat shock protein with a cytoprotect ive function. This study was undertaken to investigate the relationship bet ween alphaB-crystallin and changes seen in Alzheimer's disease. The distrib ution and immunohistochemical characteristics of alphaB-crystallin positive neurones in the cerebral cortices of 4 patients with Alzheimer's disease w ere examined. alphaB-crystallin positive neurones were mainly distributed i n the limbic and paralimbic regions, namely parahippocampal gyrus, fusiform gyrus, cingulate cortex, middle and superior frontal gyrus, and insular co rtex, which corresponded to commonly affected regions in Alzheimer's diseas e. Moreover, such neurones were present predominantly in the III or V layer of the cerebral cortex. The number of alphaB-crystallin positive neurones increased in parallel with the neuronal loss. Logistic regression analysis revealed a significant relation between the density of alphaB-crystallin po sitive neurones and that of extracellular neurofibrillary tangles (NFTs), w ith a correlation coefficient (r) of 0.57 and P < 0.0001 in 14 regions of t he cerebral cortex. In contrast, the relation was not statistically signifi cant between the density of alphaB-crystallin positive neurones and that of classical senile plaques, diffuse plaques or intracellular NFTs. Modified Gallyas-Braak (GB) staining on alphaB-crystallin positive neurone demonstra ted several patterns of the structures: faint GB positive structures in the swollen perikaryon with straight neurites, fine granules compressed and co ntorted into fuzzy bundles, intensely GB positive filamentous structures to gether with fine granules and very intensely GB positive ring-like NFTs in a swollen perikaryon with curved neurites. In positive neurones, the densit y of ring-like NFTs correlated with that of atrophic perikaryon, or bent ne urites and a decrease in the immuoreactivity of alphaB-crystallin. These da ta suggest that a close relationship exists between the appearance of alpha B-crystallin in neurones, extracellular NFTs, and neurofibrillary formation in alphaB-crystallin positive neurones in Alzheimer brain.