CXCL12 and Hyperglycemia: Additionally, hyperglycemia-induced factors, such as reduced hypoxia-inducible factor-1α (HIF-1α) transcriptional activity, decreased expression of VEGF and stromal cell-derived factor-1 (SDF-1), impair neovascularization and the functionality of endothelial progenitor cells (EPCs) [123, 124].