Endothelial progenitor cells in cardiovascular diseases: from biomarker to therapeutic agent Hui-Bin Liu, Yuan-Feng Gong, Chang-Jiang Yu, Ying-Ying Sun, Xin-Yuan Li, Dan Zhao and Zhi-Ren Zhang Regen Med Res, 1 (2013) 9 Published online: 06 December 2013 DOI: 10.1186/2050-490X-1-9