A New in Vitro Pulsatile Perfusion System that Mimics Physiological Transmural Pressure and Shear Stress in Any Size of in Vivo Vessel

Abstract

The magnitude of pressure and shear stress varies according to anatomical locations and species. It is of the utmost importance that the in vivo condition of these stresses is taken into account in in vitro experiments. In this study, we developed a new in vitro pulsatile perfusion system that is able to mimic pressures and shear stresses with accuracy and over a wide physiological range. Our system is composed of a hydraulic model of a systemic circulation. Pressure and flow rate (i.e., shear stress) were independently controlled by two resistance tubes, and pulse amplitude was controlled by air volume in a compliance tube. The resistance value of two resistance tubes and air volume in a compliance tube were calculated by system simulation. Then we recreated the pressure and shear stress of in vivo measurement data using our system. Results showed mean pressure and mean shear stress at aorta level (100 mmHg and 1.20 Pa), small artery level (80 mmHg and 1.86 Pa), arteriole level (60 mmHg and 1.41 Pa), capillary level (30 mmHg and 0.70 Pa), venule level (20 mmHg and 0.28 Pa), and vena cava level (10 mmHg and 0.15 Pa) to be recreated. We also exposed cultured human aortic endothelial cells (HAEC) to physiological pulsatile flow, which was similar to that in the human aorta at pressure 80/120 mmHg and shear stress 1.0/1.5 Pa. In the results, HAEC was elongated and oriented in the flow direction.

Keywords

• perfusion system
• hydraulic windkessel model
• pulsatile flow
• transmural pressure
• shear stress
• endothelial cells