Epo stimulates ischemia-induced neovascularization in vivo. PBS or Epo was administered by daily subcutaneous injections during the first 3 days of each week. After 2 weeks, perfusion of the ischemic limb was still impaired in PBS-treated mice (A). In contrast, Epo-treated mice showed a marked increase in hind-limb perfusion (B). Quantification of the perfusion of the ischemic hind limb relative to the contralateral, nonischemic hind limb indicated that treatment with Epo caused a significant increase in hind-limb perfusion (C). FACS analysis 7 days after induction of ischemia revealed that Epo treatment further enhanced the ischemia-induced increase in CD34⁺/flk-1⁺ cells in spleen (D) and peripheral blood (E). Data are given as means ± SD.