Tau protein, beta-amyloid1-42 and clusterin CSF levels in the differential diagnosis of Parkinsonian syndrome with dementia

Background: Parkinson's disease (PD), PD with dementia (PDD) and Lewy body dementia (DLB) are synucleinopathies. PDD and DLB are sometimes considered a transition between PD and Alzheimer dementia (AD). Finding in vivo markers or their combination could help in the differential diagnosis of these neurodegenerative (ND) diseases. Objective: The aim of this study was to assess cerebrospinal fluid (CSF) levels of tau protein, betaamyloid(1-42) and clusterin and to compare these levels among patients with probable PD, PDD, DLB and AD. Methods: CSF levels of ND markers were assessed in 96 patients (27 patients with PD, 14 with PDD, 14 with DLB, 17 with AD and 24 subjects as a control group). Results: In all of the groups of patients, beta-amyloid(1-42) levels were decreasing in the order PD > PDD > DLB > AD, whereas tau protein and the tau protein/beta-amyloid(1-42) index were increasing in the same order (PD < PDD < AD), except for DLB. In paired group comparisons, higher levels of clusterin in PD patients (p = 0.005) and PDD patients (p = 0.052) compared to the CG were found. Conclusion: The results of the present study support the role of clusterin in PD pathogenesis. The decreasing CSF beta-amyloid(1-42) levels in the order PDD, DLB and AD may relate to the increasing presence of AD pathology in these disorders. (C) 2014 Elsevier B.V. All rights reserved.