Effects of laminar shear stress on the glycocalyx layer turnover in endothelial cell after enzymatic disruption

Abstract

Endothelial glycocalyx layer (EGL) plays an important role in mechanoreceptor. Previous studies have demonstrated that the thickness of EGL is relatively thin in the region subjected to athero-prone flow condition in vivo. In this research, the effects of laminar shear stress on the EGL turnover have been studied in vitro to suggest that self-renewal of the EGL is a significant aspect of the protective nature for arterial endothelium. We have measured the loss of heparan sulfate, the most abundant component in EGL, from bovine aortic endothelial cells following heparinase III (HepIII) treatment. After this enzymatic disruption, the reconstitution of the heparan sulfate has been investigated by means of quantitative immunofluorescence imaging method under 15dynes/cm2 laminar shear stress conditions. Even though EGL-removed cells are under no-flow condition, endothelial cells start to reconstitute EGL itself. Surprisingly, EGL turnover is enhanced by fluid shear stress in injured cells as well as intact cells. After HepIII injury, EGL is fully recovered after 10 hours of shear stress, and reached the same amount of EGL of intact cells after 24 hour of shear stress. We also have observed that EGL is actively remodeled in the cell boundary under shear stress conditions. The present experiments demonstrate that removal of a severe fraction of the heparan sulfate with HepIII can be reversible. It means that re-growth of EGL allows the endothelial cells to respond again to fluid flow and aligning in the direction of flow, and inhibition of proliferation.