Endothelial Progenitor Cells: Hope Beyond Controversy

The capacity to induce new blood vessel formation or to repair damaged vessels is an attractive idea that has, for a long time, captured the attention and imagination of researchers. Beside the identification of the pro-angiogenic growth factors and their counterpart inhibitors, the discovery of endothelial progenitor cells (EPC) in adults and their putative vascular-promoting and/or vascular-healing properties, has generated some of the biggest fascination and debate in the broad field of vascular biology. The simple concept of a population of undifferentiated cells being able to generate new endothelial cells and the corresponding blood vessels in adults is both intriguing and, as seen in the last 10 years, controversial. Academic rivalry or pure scientific dispute has accompanied the research on EPC for some time. The major issues put forward by opposing groups of scientists regarding the identity and the role of EPCs as well as the optimal isolation and detection techniques are discussed in this review. The clinical relevance of EPCs and their potential applications in cancer treatments are also highlighted.