L-arginine from elder human mesenchymal stem cells induces angiogenesis and enhances therapeutic effects on ischemic heart diseases

Figure 3 Identification procedure for the potential biomarker L-arginine. A: Metabolite profiles for L-arginine differences between adipose tissue-derived mesenchymal stem cells and bone marrow-derived mesenchymal stem cells in electron spray ionization in the positive mode; B: Mass spectrum (MS) at retention time of 54.32 min; C: MS/MS spectrum of L-arginine ion from online METLIN databases; D: MS/MS spectrum of L-arginine ion at 54.32 min in plasma sample. ^bP < 0.01. ESI: Electron spray ionization; ADSCs: Adipose tissue-derived mesenchymal stem cells; BMSCs: Bone marrow-derived mesenchymal stem cells.