Study On The Kinetics Of LDL Transport In Blood Vessels

Atherosclerosis(AS)is a kind of systemic metabolic disorder caused by the deposition and growth of lipids in large and medium arteries.It is also the cause of triggering a series of heart and cerebrovascular diseases.The oxidative transport of low density lipoprotein(LDL)in blood vessels is believed to be the key to the occurrence of AS.In this paper,a convection-diffusion-reaction model of lipid accumulation in arterial vessels was established based on the knowledge of fluid mechanics,physics and biomedical sciences.The biochemical reaction,transport and deposition process of LDL and other lipids in porous vessel wall were calculated by finite element method.The transport and distribution characteristics of low density lipoprotein in arteries were analyzed.On the one hand,we calculated the diffusion and reaction process and distribution characteristics of three important lipids,namely low density lipoprotein(LDL),oxidized low density lipoprotein(LDLox)and foam cells(FC),in the intima with time at 120 mm Hg,150 mm Hg and 180 mm Hg at blood pressure.On the other hand,based on the correlation between the formation of AS and shear stress(WSS),artery structure,porosity and other factors,and considering the influence of multiple parameters of AS,an artery bifurcation model was proposed to determine the location of arterial lesions.Considering the wall pore effect,the formation and growth of AS in the lesion area and the process of lumen stenosis were studied.The numerical results show that blood pressure is in direct proportion to the diffusion of LDL and the formation of arterial plaques.The higher the blood pressure is,the more likely AS is to occur,and the growth rate of AS plaque will be correspondingly accelerated.In addition,based on the research of the arterial bifurcation model,get the lining from different parts of the bifurcation have three kinds of different degrees of injury,easy lesion area(Ω2)respectively,the general lesion area(Ω3),the safety zone(Ω1).This model provides a theoretical support for the identification of AS lesions in vulnerable areas.On this basis,by coupling the porous wall,the growth process of atherosclerotic plaque and the concentration distribution evolution of each substance molecule were calculated under different porosity.In addition,the growth rate of plaque in the lesion was faster than that in the healthy tissue.Finally,through the calculation of AS plaque volume growth,the relationship between the degree of lumen stenosis and the change of porosity was obtained,and it was found that in 10 years,the degree of vascular stenosis could reach95%,and the vessels were almost blocked.It can be seen that porosity has a great influence on the formation,development and lumen stenosis of AS.In this paper,the causes of AS formation,the growth and development of AS plaques,vascular wall thickening,lumen stenosis and endothelial dysfunction were studied.The results can explain the pathogenesis and observation results of clinical AS to a certain extent,and provide theoretical reference for the diagnosis and treatment of clinical atherosclerosis.