Of these substrates, SDF-1α is the most potent chemokine known to induce cardiovascular protection by DPP-4 inhibitors, because it has been reported that the levels of serum SDF-1α and endothelial progenitor cells increased with oral DPP-4 inhibitor treatment in patients with type 2 diabetes [36]. Here, CXCL12 is linked to type 2 diabetes mellitus.