Besides, co-administration of sitagliptin and metformin promoted a major increment in EPCs number (CD34+KDR+/CD34+CD133+KDR+) compared with monotherapy, together with an increase of glucagon like peptide-1 (GLP-1), NO, and SDF-1α levels in T2DM patients [182]. Here, GCG is linked to type 2 diabetes mellitus.