Interstitial flow through the internal elastic lamina affects shear stresson arterial smooth muscle cells

Interstitial flow through the tunica media of an artery wall in the presenc e of the internal elastic lamina (IEL), which separates it from the subendo thelial intima, has been studied numerically. A two-dimensional analysis ap plying the Brinkman model as the governing equation for the porous media fl ow held 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 EEL. The tunica media was modeled as a heterogeneous medium composed of a periodic array of cylindrical smooth mu scle cells (SMCs) embedded in a fiber matrix simulating the interstitial pr oteoglycan and collagen fibers. A series of calculations was conducted by v arying 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 mu m), and the distance between the IEL and the nearest SMC (0.2-0.8 mu m). The results indicate that the value of the average shear stress around the circumference of the SMC in the immediate vicinity of the fenestral po re could be as much as 100 times greater than that around an SMC in the ful ly developed interstitial flow region away from the IEL. These high shear s tresses can affect SMC physiological function.