Tada S, Tarbell J M
Energy Phenomena Laboratory, Department of Mechanical Engineering and Science, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
Am J Physiol Heart Circ Physiol. 2000 May;278(5):H1589-97. doi: 10.1152/ajpheart.2000.278.5.H1589.
Interstitial flow through the tunica media of an artery wall in the presence of the internal elastic lamina (IEL), which separates it from the subendothelial intima, has been studied numerically. A two-dimensional analysis applying the Brinkman model as the governing equation for the porous media flow field was performed. In the numerical simulation, the IEL was modeled as an impermeable barrier to water flux, except for the fenestral pores, which were uniformly distributed over the IEL. The tunica media was modeled as a heterogeneous medium composed of a periodic array of cylindrical smooth muscle cells (SMCs) embedded in a fiber matrix simulating the interstitial proteoglycan and collagen fibers. A series of calculations was conducted by varying the physical parameters describing the problem: the area fraction of the fenestral pore (0. 001-0.036), the diameter of the fenestral pore (0.4-4.0 microm), and the distance between the IEL and the nearest SMC (0.2-0.8 microm). The results indicate that the value of the average shear stress around the circumference of the SMC in the immediate vicinity of the fenestral pore could be as much as 100 times greater than that around an SMC in the fully developed interstitial flow region away from the IEL. These high shear stresses can affect SMC physiological function.
在存在将动脉壁中膜与内皮下内膜分隔开的内弹性膜（IEL）的情况下，对穿过动脉壁中膜的间质流进行了数值研究。应用布林克曼模型作为多孔介质流场控制方程进行了二维分析。在数值模拟中，IEL被建模为除了在IEL上均匀分布的窗孔之外对水流不可渗透的屏障。中膜被建模为由嵌入模拟间质蛋白聚糖和胶原纤维的纤维基质中的圆柱形平滑肌细胞（SMC）的周期性阵列组成的非均质介质。通过改变描述该问题的物理参数进行了一系列计算：窗孔的面积分数（0.001 - 0.036）、窗孔的直径（0.4 - 4.0微米）以及IEL与最近的SMC之间的距离（0.2 - 0.8微米）。结果表明，在窗孔紧邻区域的SMC周围圆周上的平均剪应力值可能比远离IEL的充分发展的间质流区域中的SMC周围的平均剪应力值大100倍之多。这些高剪应力会影响SMC的生理功能。
