ABSTRACT
Recent neuropathological studies have described widespread amyloid-ß peptide (Aß) deposition in the striatum of patients with Lewy body disorders, particularly in Parkinson's disease with dementia (PDD) and dementia with Lewy bodies (DLB). However, positron emission tomography (PET) studies using the [(11)C]PIB ligand, binding to Aß deposits, detects significant striatal pathology only in DLB and not in PDD. Employing immunohistochemistry, we examined striatal Aß deposition in the caudate nucleus and putamen of 52 PD, 41 PDD, 14 DLB, 7 multiple system atrophy (MSA) and 14 progressive supranuclear palsy (PSP) cases in relation to the presence of dementia. PD, MSA and PSP cases showed little or no Aß pathology in the striatum. In contrast, both PDD and DLB cases demonstrated significantly greater Aß deposition in the striatum when compared to PD, MSA and PSP groups. We conclude that striatal Aß pathology is common in both PDD and DLB and may reflect the development of dementia in these conditions. More detailed examination of the morphology of the Aß pathology suggests that it is the presence of cored amyloid plaques in DLB, but not PDD, that underlies the differences seen in PET imaging.
