Degenerative terminals of the perforant pathway are human alpha-synuclein-immunoreactive in the hippocampus of patients with diffuse Lewy body disease

We investigated the hippocampal pathology in diffuse Lewy body disease (DLB D) using alpha-synuclein immunohistochemistry. Ubiquitin-positive intrahipp ocampal structures caused by the degeneration of terminal axons of the perf orant pathway were observed to be alpha-synuclein immunoreactive. These alp ha-synuclein-positive degenerative terminals contained granulo-filamentous or vesiculo-tubular components similar to those of Lewy bodies (LB) immunoe lectron microscopically, suggesting that alpha-synuclein may abnormally agg regate into filamentous or membranous cytoskeletal components including neu rofilaments and synaptic vesicles in DLBD. A 'dying back' degenerating proc ess due to a blockage of axonal transport may explain why the degenerative terminals and LB share similar alpha-synuclein-positive components, but the origin cells of the perforant pathway contain only a few LB. (C) 1998 Else vier Science Ireland Ltd. All rights reserved.