Background Vascular regeneration involves the contribution of endothelial progenitor cells (EPCs).We and others reported recently that the angiogenic factor CCN1 stimulates EPCs migration, proliferation, and participation in angiogenesis.Because CCN1, a secreted matricellular protein, has been shown to participate in stern/progenitor cells differentiation and tissue regeneration, we hypothesized that CCN1 may regulate EPCs differentiation and thus contribute to vascular regeneration.