Accumulation of human α-synuclein in different cytoskeletons in Lewy bodies in brains of dementia with Lewy bodies

We investigated the origin of alpha-synuclein-immunoreactive components in Lewy bodies (LB) in brains of dementia with Lewy bodies (DLB) using immunohistochemistry and immunoelectron microscopy with anti-alpha-synuclein antibodies and anti-cytoskeleton antibodies, alpha-Synuclein-positive LB light microscopically consisted of phosphorylated neurofilament(PN)-positive LB, tubulin-positive LB and LB that were negative for both stains. Immunoelectron microscopically, PN-positive LB were com posed of PN-positive and alpha-synuclein-positive filamentous components, suggesting that these filamentous components originate from neurofilaments with partially reduced immunoreactivity and alpha-synuclein accumulation. However, tubulin-positive LB were composed of tubulin-positive and alpha-synuclein-positive tubular components, suggesting that these tubular components originate from microtubules with diffusely reduced immunoreactivity and alpha-synuclein accumulation. The results of the present study suggest that alpha-synuclein accumulates in different cytoskeletons in the LB in DLB brains presumably due to a blockage of axonal transport. (C) 2000 Published by Elsevier Science Ireland Ltd.