The summary of findings by Dr. Shimizu and his collaborators is highly appreciated [1]. His comment is of great help to understanding the concept that an appropriate level of CD34-positive cells for each person may be associated with vascular health. He also pointed out the pitfalls of functional atherosclerosis. Since CD34-positive cells are not easily and routinely measured, I hope further studies will clarify the mechanisms of endothelial repair, establish the pathophysiological significance of CD34-positive cells, and advance the clinical applications for cardiovascular disorders.