Abstract
Glycosaminoglycans (GAGs) on the surface of the endothelium and basement membrane have been suggested to be involved in vascular permeability, anticoagulation, cell movement and cell growth. In the present study, we demonstrated that fluid laminar shear stress enhanced syntheses of GAGs in porcine aortic endothelial cells, in vitro. Shear stress (15, 40dyn/cm2) for 24 hours significantly increased GAG synthesis and secretion, assayed by [35S] sulfate incorporation, in “medium” and “trypsinated” fractions which include GAGs derived from the cell surface and from the solubilized matrix. The GAGs induced by shear stress (40dyn/cm2) in the trypsinated and medium fractions consisted mainly of heparan sulfate and chondroitin/dermatan sulfate, respectively. For both heparan and chondroitin/dermatan sulfate increases exposure of the cells to shear stress for more than 24 hours was required. Shear stressinduced increase in GAG synthesis was concomitant with a decrease in DNA synthesis and an increase in protein synthesis. Since DNA synthesis in static cells also was in inverse proportion to the GAG synthesis, GAGs on the surface of cells and/or extracellular matrix may involve cell growth. These findings indicate that relatively high shear stress may suppress atherogenesis by changing endothelial GAG synthesis.
