Background: The arterial wall intima is composed of endothelial cells and fenestrated elastic lamina adjacent to the smooth muscle cells of the tunica media. This intra-arterial barrier is subjected to the physical stresses imposed by the flowing blood. We developed a multi-layer tissue-engineered barrier that mimics the inner in vivo structure of the arterial intima in order to allow for in vitro mechanobiology studies.
Methods: A co-culture of endothelial and smooth muscle cells has been developed on a collagen-coated PTFE synthetic membrane. We used custom-designed wells developed in our lab that can be disassembled for insertion of the co-culture model in flow chambers. The collagen coated membrane was also coated with human fibronectin and then seeded with human umbilical arterial smooth muscle cells (HUASMC). After 24 hours we coated the HUASMC with collagen and seeded with human umbilical vein endothelial cells (HUVEC). After an additional 2 days, the tissue engineered barrier was ready for application of wall shear stresses (WSS) induced by steady flow.
Results: Confocal imaging was used to verify that the in vitro model is composed of a multi-layer model of HUVEC on top of HUASMC. We used antibodies that depicted the actin, focal adhesion and VE-cadherin of the HUVEC and the HUASMC actin. Then, we exposed the co-culture model to steady WSS 4 and 12 dyn/cm2.
Conclusions: We developed an in vitro model of the arterial intimal barrier and investigated the inter-connection effects between the endothelial and smooth muscle cells under simulations of physiological WSS.