Hydrodynamic Characterization of an Arterial Flow Bioreactor

In vitro arterial flow bioreactor systems have been used in tissue engineering as models to investigate the response of endothelial cells to shear. However, the degree to which such models can reproduce physiological flow has not been quantified. Furthermore, previous works have assumed a Poiseuille flow profile for the calculation of wall shear stresses (WSS) experienced by the endothelial layer. To test the reliability of these systems and the accuracy of the Poiseuille assumption, a typical bioreactor used for tissue engineering was seeded with a layer of human microvascular endothelial cells on the lumen of the vessel section and integrated with a flow loop to generate pulsatile flow. A particle image velocimetry (PIV) system was used to experimentally measure the flow within the bioreactor vessel. The instantaneous and time-averaged WSS and oscillatory shear index were compared for different flow conditions and used to assess the system for study of the hydrodynamic response of biological tissues. It was determined that the flow present in such a system is not an accurate reproduction of physiological flow. In light of these findings, conclusions about cellular response to hemodynamic parameters that were drawn from studies using such bioreactor flow systems should be reexamined.