Albumin Permeability across Endothelial Monolayers under Long-Term Shear Stress

Endothelial cells lining the inner surface of blood vessels regulate the exchange of molecules between the blood and the vessel wall. This study investigates the effect of long-term shear stress on macromolecule permeability across endothelial monolayers. In vitro system to measure transendothelial permeability to tetramethylrhodamine conjugated albumin under shear stress was developed. The temporal variation in albumin permeability under 1Pa and 4Pa over 48h was quantified using a fluorescence spectrophotometer. At 4Pa, albumin permeability did not show a statistical significant change over 48h. Under shear stress of 1Pa, the average albumin permeability between 12 and 30h was 2.5-fold higher than the average between 0 and 6h. Under shear stress of 1Pa, the average albumin permeability between 36 and 48h was 1.8-fold higher than the average between 12 and 30h. These results show that both the magnitude of, and the length of exposure to, shear stress regulate transendothelial permeability.