CSF α-synuclein levels in dementia with Lewy bodies and Alzheimer's disease

Dementia with Lewy bodies (DLB) is characterized by widespread depositions of α-synuclein, which are described as Lewy bodies. Recently, it was shown that neuronal cells in culture constitutively release α-synuclein into the culture medium and that α-synuclein is normally present in human cerebrospinal fluid (CSF). The aim of the present study was to evaluate the diagnostic value of CSF α-synuclein levels in discriminating DLB from Alzheimer's disease (AD). α-Synuclein was measured in CSF from 16 patients with DLB and 21 patients with AD. Iodine-123 metaiodobenzylguanidine cardiac scintigraphy was also performed to assess Lewy body pathology. CSF α-synuclein levels did not differ significantly between DLB and AD patients. However, the duration of illness was associated with lower α-synuclein levels (p < 0.05) in DLB, while no such association was found in AD. The present data show CSF α-synuclein levels are not sensitive diagnostic markers to discriminate DLB from AD. However, the lower α-synuclein levels in DLB patients with longer duration suggest a reduction in CSF α-synuclein in association with increased severity of α-synucleinopathy in the brain.