CXCR4 and type 2 diabetes mellitus: For instance, a 4-week sitagliptin treatment increased EPCs (CD34+/CD34+KDR+) and SDF-1 levels in T2DM patients [179], in agreement with another study in which 12-weeks sitagliptin treatment doubled the number of EPCs (CD34+CXCR4+) in these patients [180].