Chronic In Vitro Flow Promotes Ultrastructural Differentiation of Endothelial Cells

Abstract

Endothelial cells in vivo are exposed to flowing blood and are therefore subject to continuous apical shear stress. This study explored the feasibility of endothelial cell culture with chronic shear stress. Bovine glomerular capillary and aortic endothelial cells were cultured under conventional conditions without flow, or in polypropylene hollow fibers perfused for 9 days with venous or arterial shear stress. Cells were then examined by scanning and transmission electron microscopy. For both cell types, ultrastructural differences between conventional culture and culture with chronic arterial flow were quantified morphometrically. In the hollow fibers, capillary and aortic endothelial cells formed adherent, confluent monolayers with chronic flow, but not without flow. With venous and arterial shear stress, aortic, but not glomerular capillary endothelial cells, aligned themselves in the direction of flow. In aortic endothelial cells, the density of Weibel Palade bodies was, on average, 38 fold greater wi...