Endothelial Nitric Oxide Concentration and Its Implications in Carotid Artery Atherosclerosis – An Integrated Cell/Haemodynamics Approach

Atherosclerotic plaques are believed to develop where the bioavailability of nitric oxide (NO) is low. Based on that plaques often localise in the specific regions of vasculature where wall shear stress (WSS) is low, a relationship between local NO concentrations and geometrical factors has been postulated. A mathematical model of NO synthesis in the endothelium has been developed. NO is first computed using the conventional method, i.e. using the endothelial cell (EC) stretch in the flow direction only. The results point to that low WSS leads to low NO wall concentration due to impaired EC signalling. Then NO is computed with the circumferential stretch (CS) of EC membrane also included, incorporating the effects of pusatile-flow induced pressure variation on cell signalling. The results also showed the low-WSS regions coinciding with low NO sites, though the range of spatial variation decreased.