Plasma Metabolome Signature in Patients with Early-stage Parkinson Disease

Background: Recent decades have been marked by advances in omics sciences based on high-throughput technologies, which have enabled the measurement of enormous numbers of molecules in biosamples. In metabolomics, a large number of small molecules (metabolome) can be detected in a single run. The goal of this study was to evaluate the capacity for metabolomic analysis of blood plasma for early-stage Parkinson Disease (PD) diagnosis. Methods: Blood plasma samples collected from control subjects (n = 20) and patients with PD (Hoehn and Yahr stages 1, 1.5, and 2; n = 16) were treated with methanol, and low-molecular-weight fractions were analyzed by direct infusion mass spectrometry. Metabolite ions that exhibited strong association with PD were included in a diagnostic signature compilation and corresponding characteristics for PD diagnosis were calculated. For metabolite ions included in the signature, correspondence to specific metabolites in metabolite databases was established. Results: A total of 21 metabolite ions that were strongly associated with PD were used to compile a metabolome signature. The area under a receiver operating characteristic curve (AUC) for PD diagnosis calculated for the signature was 0.95 (accuracy 94%, specificity 95%, and sensitivity 94%). Metabolites identified in this study were consistent with factors that had been associated with the development of PD previously. Conclusion: Direct infusion mass spectrometry of blood plasma metabolites represents a rapid singlestep method with potential for application in early-stage PD diagnosis.