Recent studies have shown that shear stress also inhibits apoptosis of vascular endothelial cells (ECs).1,2 In contrast, flow that has low mean shear stress and turbulence is strongly correlated with EC dysfunction, EC apoptosis, and atherosclerosis.3–5 In accordance with our previous studies,6,7 we found that physiologic shear stress inhibits EC apoptosis partly by activating the human inhibitor of apoptosis protein-2 (HIAP-2) protein and X-linked inhibitor of apoptosis protein (XIAP) protein. This evidence concerns the gene XIAP and atherosclerosis.