Morphological changes of endothelial cells after exposure to fluid-imposed shear stress: differential responses induced by extracellular matrices

Effects of extracellular matrices (ECMs) and fluid-imposed shear stress on the cell shape and the cytoskeletal structure of microfilaments were studied in cultured porcine aortic endothelial cells (PAECs). The PAECs were cultured until confluent on non-coated or on ECM-coated glass coverslips. The components of ECM used were type IV collagen, heparan sulfate, chondroitin sulfate and dermatan sulfate. The PAECs cultured on the mixed ECMs showed marked elongation and segmental orientation with randomly distributed cell axis even under a no-flow static condition, and the microfilaments were mostly observed in parallel with the cell axis. After shear flow exposure (2 Pa, 24-48 hrs), the PAECs on non-coated glass were significantly elongated and oriented to the flow direction, however the PAECs on ECM-coated glass showed more retarded responses than the ones on non-coated glass, indicating that the anchorage to the substrate was enhanced by ECMs. The stress fibers were reorganized in accordance with the cell shape and oriented to the flow direction. These findings suggest that ECM may act together with shear stress to modify and maintain the endothelial cell configuration.