[The significance of oxidized DJ-1 protein (oxDJ-1) as a biomarker for Parkinson's disease].

The search for biomarkers of Parkinson's disease (PD) typically focuses on cerebrospinal fluid components, with very few reports on simple biomarkers identifiable by blood analysis. In this report, we determined the level of oxidized DJ-1 protein (oxDJ-1) in red blood cells by ELISA and examined the association with MIBG myocardial scintigraphy. Levels of oxDJ-1 were higher in unmedicated patients with PD (142.2 ± 21.8 ng oxDJ-1/mg protein; n = 13) compared to the L-DOPA-treated group (85.6 ± 10.1 ng oxDJ-1/mg protein; n = 10) and controls (56.0 ± 6.2 ng oxDJ-1/mg protein; n = 17), thereby showing significant intergroup differences. Intervention with L-DOPA showed a tendency to decrease oxDJ-1 levels in patients. The diagnostic sensitivity of oxDJ-1 measurement was 87% and that of simultaneously conducted MIBG scintigraphy was 89%; this showed that the diagnostic sensitivity was comparable. Our results showed that measurement of oxDJ-1 levels in red blood cells can be useful and oxDJ-1 can be used as a biomarker for the early diagnosis of PD. (Receieved July 31, 2013; Accepted October 16, 2013; Published April 1, 2014).