GC-MS analysis of plasma metabolites
Metabolomic analysis based on GC-MS was performed as previously detailed (9). Metabolomic profiling was carried out by a GC–MS analyzer (Shimadzu GCMS‐QP2010 Ultra, Kyoto, Japan) with a DB‐5MS stationary phase column (30 m + 10 m DuraGuard × 0·25 mm i.d. and 0·25‐μm film thickness). Sample injections were done in splitless mode. The oven temperature program was fixed at 60°C for one minute, then increased gradually to 325°C by an increase of 10°C each minute and held for 10 minutes at 325°C. The total separation time was 37.5 minutes. Electron impact ionization was carried out at 70 eV. Data acquisition was performed in full scan mode with a mass range between 50 and 650 m/z.