Objective/Rationale:
Recent studies have linked lysosomal dysfunction to the accumulation of alpha-synuclein oligomers and alpha-synuclein-mediated cell death. Clinical, neuropathological and genetic associations between Gaucher’s disease, a lysosomal storage disease, and Parkison’s disease (PD) have been reported. Furthermore, a reduction of the activities of beta-glucocerebrosidase, alpha?? and beta-mannosidase has been reported in CSF of PD patients.
Project Description:
De-novo and treated patients referring to the Section of Neurology, University of Perugia, Italy, will be included in the study. CSF samples will be collected from patients with PD (n=80) and healthy subjects (n=50). Lysosomal enzyme activities (beta-glucocerebrosidase, alpha-mannosidase, beta-mannosidase, beta-hexosaminidase, beta-galactosidase, alpha-fucosidase, arylsulfatase A, arylsulfatase B, cathepsin D, and cathepsin S) will be determined in CSF samples using specific fluorimetric substrates.
The levels of monomeric and oligomeric alpha-synuclein, using a sensitive and specific ELISA method able to reveal levels as low as 1 pg/mL in human biological fluids, including plasma and CSF, will be also evaluated. Statistical analysis will be carried out using the Analyse-it (Analyse-it Software). Correlation analysis (Spearman’s rho coefficient) between lysosomal enzyme activity and alpha-synuclein will be also carried out.
Relevance to Diagnosis/Treatment of Parkinson’s Disease:
To date there is no accepted diagnostic test for Parkinson’s disease based on biochemical analysis of blood or cerebrospinal fluid (CSF). The potential use of CSF lysosomal enzyme activities as a diagnostic indicator, or as a marker of disease progression in PD, will be investigated. Moreover, the CSF levels of alpha-synuclein – a candidate diagnostic biomarker of PD – will be combined with the lysosomal enzyme activities in order to verify if there is any association between these biochemical parameters.
Anticipated Outcome:
(i) to verify if changes in the activities of a large number of lysosomal enzymes in CSF of PD patients can be considered a diagnostic biomarker of the disease or a marker of disease progression; (ii) to confirm the specific behavior of CSF beta-glucocerebrosidase activity in PD patients; (iii) to evaluate the added value of determining also the levels of CSF alpha-synuclein.