Editorial Commentary Angiotensin II Deteriorates Endothelial Progenitor Cells Good Intentions With Bad Consequences

Approximately 15 years ago it was discovered that thebone marrow and blood harbor stem cells with angio-genic potential.1 Because some of these stem cells express endothelial markers, it is believed that they are endothelial progenitor cells (EPCs) that will contribute to the mainte-nance of the circulatory system and develop into adult endothelial cells. Many studies followed to unravel the physiological role and the therapeutic application of EPCs. All of these research endeavors did not yet lead to a consensus regarding the identification of true EPCs, and EPC quantification remains subjective.2 To complicate matters even more, it has now been proposed that nonendothelial CD31 bone marrow cells participate in neovascularization.3 It is, therefore, not only complicated for the investigator to compose a satisfactory study design but also for the reader to evaluate the results. Preferably, such studies investigat