혈관 모사 시스템에서 세포외기질의 조절에 따른 혈관내피세포의 생리적 변화 연구

Abstract

Organ on a chip is a biomedical technology that implements the functions and characteristics of a specific organ on a small chip. In this study, we focused on blood vessels among various organs of the human body. We intend to implement an in-vitro vessel system that can be a model of cardiovascular disease to conduct studies that focus on vessels that play a role in connecting vital organs. We selected atherosclerosis, which is one of the cardiovascular diseases. One of the main factors from atherosclerosis is the dysfunction of vascular endothelial cells. We chose three atherosclerotic characteristics; low shear stress, stiff substrate, and high deposition of fibronectin in extracellular matrix; to realize the dysfunctional vascular endothelial environment. These environmental characteristics were simulated on a chip for culturing vascular endothelial cells. First, the shear stress was applied to the cultured cells by flowing a constant amount of culture medium through a peristaltic pump. The cellular substrate was created using a hydrogel capable of controlling stiffness to create a similar environment to the cell bases and regulated within the range of normal and abnormal blood vessels. We used 4 types of stiffness, 0.3, 2.4, 19.2, and 153.6 kPa, using polyacrylamide solution. The extracellular matrix proteins were coated on polyacrylamide gels with collagen or fibronectin, respectively, and the cells were cultured on the gel, and then observed every 5 minutes for 24 hours. We used bovine aortic endothelial cells (BAECs), and cell morphology and migration were quantified by various methods according to the respective conditions. In an environment with little or no shear stress, the shape of the cells is close to circular, and no specific directionality is observed in migration. One of the most interesting observation is that unlike cells on a stiffer substrate that are less aligned in the flow direction, these cells move much faster to adapt to flow. Finally, we observed that cells on the coated surface of fibronectin were more sensitive to substrate stiffness than collagen-coated surfaces. In this study, we observed a more random alignment and migration of cells in the environment that simulated the environmental features of atherosclerosis. These features were similar to behaviors of vascular endothelial cells in blood vessels that are more vulnerable to atherosclerosis. Through this study, various environmental characteristics of atherosclerosis were utilized to implement an environment simulating cell dysfunction, which is one of the leading cause of atherosclerosis, on a chip. Based on this study, we hope to be able to conduct basic studies on various physiological changes in cells through observation of cells in atherosclerotic environment.