Blood sample collection and metabolites extraction
peripheral venous blood sample
A 10 mL peripheral venous blood sample was collected from all participants in both groups. Subsequently, the samples were centrifuged at 3000 rpm for 10 min, and the resulting supernatant was aliquoted into 1.5 mL centrifuge tubes and stored at -80 °C. For analysis, 100 μL of each sample was transferred to an EP tube. To this, 400 μL of extract solution (methanol containing isotopically-labelled internal standard mixture) was added, followed by 30 s of vortexing, 10 min of sonication in an ice-water bath, and 1 h of incubation at -40 °C to precipitate proteins. The sample was then centrifuged at 12,000 rpm (RCF = 13,800(× g), 