CXCR4 and diabetes mellitus: Collectively, our data suggest that the SDF-1α/CXCR4 axis is impaired at multiple sites (brain and EPCs) in diabetes, which might have implications in cerebral ischemic damage and repair (enlarged injury and delayed repair); targeting on the dysfunction of SDF-1α/CXCR4 axis could offer a new avenue for treating ischemic stroke in diabetes.