Effect of endothelial injury and increased blood pressure on albumin accumulation in the arterial wall: a numerical study

The present study investigates the influence of endothelial damage and of b lood pressure on albumin accumulation in the arterial wall. For this purpos e a numerical model for the coupled mass transport processes in the arteria l lumen and in the various layers of the arterial wall is developed. The mo del considers the transport in the endothelium, intima, internal elastic la mina (IEL) and media of a straight axisymmetric arterial segment. In the ar terial lumen fully developed stationary blood flow is assumed, the filtrati on velocity in the wall layers is calculated applying Darcy's law. The desc ription of the luminal mass transport uses the stationary convection-diffus ion equation, the transport in the porous intima and media is modelled appl ying the volume-averaged stationary convection-diffusion-reaction equation. The transport processes in the lumen, intima and media are coupled by the flux across the endothelium and IEL, which is mathematically described usin g the Kedem-Katchalsky equations. The numerical solution of the transport e quations applies the finite element method. The results demonstrate a high resistance of the healthy endothelium to mac romolecule exchange between blood and the artery wall. The reduced resistan ce of an injured endothelium causes an increased mass flux into the wall wh ich results in higher concentration levels within the wall. The effect of t he blood pressure on the wall concentration level is different for a health y and an injured endothelium. In the case of a healthy endothelium a blood pressure increase causes a decrease of the intimal concentration and an inc rease of the medial concentration, whereas in the case of an injured endoth elium an increased blood pressure results in higher concentration levels wi thin the intima and media. (C) 2000 Elsevier Science Ltd. All rights reserv ed.