Shear dependent albumin uptake in cultured endothelial cells

To clarify the process of plasma protein uptake, we focused on a negatively charged glycocalyx on the cell surface, since the glycocalyx electrostatically supposed negatively charged protein uptake such as albumin, and the glycocalyx thickness was varied with the variation of shear stress on the surface. After subjected bovine aorta endothelial cell to various shear stress (0.5, 1.0, 2.0, 3.0 Pa) for 48 hours, we determined the glycocalyx thickness with electron microscopy and lead cationic particle, toluidine blue, to bind to anionic charged glycocalyx and measured absorbance of the binding amount with spectrophotometer. We measured the albumin uptake from acquired fluorescent images of fluorescent labeled albumin with confocal laser scanning microscopy at neutralized glycocalyx charge and non-treatment. The albumin uptake on non-treatment, increased at comparatively low shear stress (0.5, 1.0, 2.0 Pa), and decreased at comparatively high shear stress (3.0 Pa). The albumin uptake on neutralized charged cell increased about two fold of non-treatment at 3.0 Pa (P <0.001). From this study, we found that the glycocalyx thickness and charge were constant at low shear stress, but changed thicker and higher than control at comparatively high shear stress. This result indicates that glycocalyx has the influence on albumin uptake at comparatively high shear stress.