Cell-cultured PDMS vascular model to allow placement of implant devices

Abstract

BackgroundA stent maintains normal blood flow by expanding a stenotic artery from the inside. Stents currently in clinical use are mechanically sub-optimized and, therefore, exert excessive mechanical stimuli on the vascular wall. This can lead to arterial inflammation and potentially in-stent restenosis. To optimize the force exerted by a stent on the vascular wall, we should understand, reproduce, and analyze in detail the mechanical field to which the stented vessel is exposed. However, to date, no in vitro model has been established that can adequately evaluate the mechanical effects of a stent on the vascular wall and be constructed without relying on a laboratorys know-how. This study aims to develop a three-dimensional in vitro vascular model that allows stent placement and to provide the details of its construction method. MethodsPolydimethylsiloxane (PDMS) was used to mimic the adventitial structure of arteries. Human carotid artery endothelial cells (HCtAECs) were then seeded on the luminal surface and cultured for 24 h to form a confluent monolayer (intima). The constructed model was installed in the flow-exposure culturing system, and hemodynamic stimulation (two types of shear stress (SS); 0.5 Pa and 2.3 Pa) was applied to the HCtAECs inside to reproduce the physiological state of blood vessels. In addition, a self-expanding stent was placed in the model during perfusion culture. ResultsWe examined the performance of the developed model based on quantitative evaluations of endothelial morphology in response to SS and in-stent endothelialization. Exposure to SS for 24 and 48 h caused endothelial orientation and elongation in the direction of flow, confirming the physiological responses of blood vessels. We were also able to quantitatively evaluate endothelial migration (endothelialization) to the stent. DiscussionOur model can reproduce the mechanical field inside the stented blood vessel, including hemodynamic stimuli. Based on the results obtained, the developed cell-cultured vascular model has sufficient performance to be used not only for quantitative evaluation of in-stent endothelialization but also for optimization of the mechanical fields in the stented vessel.