Fig. 1

Schematic of study design and analytical pipeline: (1) sample collection from CTL, PD-I and PD-II; (2) clinical evaluation; (3) metabolomic analysis by absolute quantification; and (4) data analysis and biomarker discovery.

Schematic of study design and analytical pipeline: (1) sample collection from CTL, PD-I and PD-II; (2) clinical evaluation; (3) metabolomic analysis by absolute quantification; and (4) data analysis and biomarker discovery.