Modelling the early stages of atherosclerosis

Atherosclerotic lesions are predominantly localised to arterial bifurcations and bends, and are highly correlated with areas of low wall shear stress (WSS), but the underlying reason for this localisation is not fully understood. A key role is played by the endothelial cells, which regulate the transport of materials from the bloodstream to the artery wall and secrete vasoactive agents that modulate vascular tone. A mathematical model is presented, exploring the link between arterial geometry, WSS and factors related to atherogenesis. The model simulates the cellular response to the fluid shear stress on the cell membrane and the binding of ligands to cell surface receptors. This is used to calculate the rate of production of nitric oxide (NO), which is a potent vasodilator and anti-atherogenic factor. It is hypothesised that the section of endothelium adjacent to a region of recirculating flow is most at risk of developing atherosclerotic plaque, due to reduced bioavailability of NO.