MACROMOLECULAR TRANSPORT THROUGH THE DEFORMABLE POROUS-MEDIA OF AN ARTERY WALL

To determine the macromolecular transport properties of the tunica med ia of an artery wall deformed inhomogeneously by the transmural pressu re, we combine a simple mechano-hydraulic model based on a two paramet er strain-dependent permeability function, which was developed by Klan char and Tarbell (1987), with a fiber matrix theory. The combined theo ry allows us to calculate the spatial distributions of porosity, solut e partition, fiber radius and macromolecular solute concentration in t he media and their dependence on the transmural pressure. The predicti ons from the combined theory are in good agreement with experimental m easurements of sucrose space, albumin space and albumin concentration profiles in the media of rabbit aortas at transmural pressures of 70 a nd 180 mmHg. The predictions indicate that albumin transport through t he aortic media is dominated by convection rather than diffusion. It i s further demonstrated that the transport properties of unstressed pla nar tissue samples, which are often used in in vitro experiments, may be quite different from those of intact vessels in their natural cylin drical configuration because of variation in tissue deformation.