EXPERIMENTAL ANALYSIS AND COMPUTER SIMULATION OF A PLAQUE FORMATION

Objectives: The inflammatory process starts with the penetration of low density lipoproteins (LDL) in the intima. This penetration, if too high, is followed by leucocyte recruitment in the intima. This process may participate In the formation of the fatty streak, the initial lesion of atherosclerosis and then in formation of a plaque. Quantification of parameters for LDL transport and plaque formation is a huge challenge for the medical community. Methods: In this study, an experimental model of LDL transport on the isolated blood vessel from rabbit on high fat diet after 8 weeks is simulated numerically by using a specific model and histological data. The 3D blood flow is governed by the Navier-Stokes equations, together with the continuity equation. Mass transfer within the blood lumen and through the arterial wall is coupled with the blood flow by the convection-diffusion equation. LDL transport in lumen of the vessel is described by Kedem-Katchalsky equations. The inflammatory process is solved using three additional reaction-diffusion partial differential equations. All parameters for computer model were fitted with non-linear least square procedure. Results: Matching of histological rabbit data is performed using 3D histological image reconstruction and 3D deformation of elastic body. Concentration of macrophages obtained by computer simulation indicates that there is a newly formed matter in the intima, especially in the 5mm region before bifurcation. Computed concentrations of labeled LDL of 13% are in good agreement with experimental results. Conclusions: Matching of labeled LDL and macrophages concentration and location between experimental and computer model shows a potential benefit for future prediction of this complex process using computer modeling.