Morphological effects of spatial and temporal gradients of shear in a faithful human right coronary artery cell culture model

Abstract

Dysfunction of the vascular endothelium can initiate atherosclerosis. Mechanical forces, particularly wall shear stress (WSS) are believed to cause endothelial dysfunction. Present in vitro cell culture models are often simplified and thus, ignore the wall shear stress spatial gradients inherent in complex geometries. The aim of this project was to study endothelial cell response in an anatomically correct right coronary artery model (RCA) under more physiologically realistic flow conditions.Human Abdominal Aortic Endothelial Cells (HAAECs) were seeded in the lumen of a pre-treated faithful RCA and a straight tubular model. The cells were subjected to steady or non-reversing oscillatory flow (Re=196, alpha=1.82) at a mean physiological flow rate of 20 dynes/cm2 for 8, 12 and 24 hours of flow. The results show that under all flow conditions, the cells became progressively more elongated and aligned. Moreover, differences in endothelial morphology in the inner (myocardial) and outer (pericardial) walls were seen in the inlet region. The morphologic adaptation to steady and oscillatory flow was similar. The results suggest that spatial, not temporal gradients in shear in the inlet region are responsible for the differential endothelial cell response