Background Increasing evidence suggests endothelial progenitor cells (EPCs) improve neovascularization and endothelium regeneration via the production of paracrine factors.Vascular endothelial growth factor (VEGF) and interlettkin-8 (IL-8) are major cytokines for EPC-based angiogenesis and re-endothelialization.In our previous studies,homocysteine (Hey) impaired EPC migratory and adhesive activity.However, the mechanism of homocysteine on paracrine function of EPCs still needs further reasearch.We undertook this study to determine whether Hcy could affect the expression and secretion of VEGF and IL-8 from EPCs.