Effects of wall shear stress on NO simulation in arterioles

The shear stress acting on the endothelium is a dominant mechanical stimulus that modulates the production rate of NO in the endothelial cells. Thus, determination of the wall shear stress (WSS) is important in studying the flow‐induced vasodilation. Recently, we have reported a way to estimate WSS in small arterioles by measuring the cell‐free layer width and edge velocity of red cell core, and used the method in NO simulation studies. In using that method, we assume that the flow within the cell‐free layer is steady. However, it has been known that variations in flow velocity due to the arterial pulse would exist in arterioles. Thus, in this study, we have considered temporal changes of the edge velocity of red blood cell core resulting from the temporal cell‐free layer width variations in estimating the WSS in the vessels. Linear and non‐linear velocity profiles within the layer were used to estimate the WSS. The temporal variation results of the WSS were utilized to predict NO bioavailability in the arterioles. We found a slight but significant difference in estimated WSS by using different velocity profiles in the cell‐free layer. However, NO simulation showed that this slight difference of WSS did not lead to a significant change in NO bioavailability. This work was supported by NUS URC Grant R‐397‐000‐091‐112.