Tissue-Engineered Vascular Grafts as In Vitro Blood Vessel Mimics for the Evaluation of Endothelialization of Intravascular Devices

The accelerating use of minimally invasive procedures for the treatment of cardiovascular disease, and the commensurate development of intravascular devices such as stents, has lead to a high demand for preclinical assessment techniques. A 3-dimensional in vitro blood vessel mimic (BVM) would be ideal for device testing before animal or clinical studies. This is possible based on current capabilities for the creation of tissue-engineered vascular grafts (TEVGs). Using an established method of pressure-sodding human endothelial cells onto a polymer scaffold, a BVM was created in an in vitro bioreactor system under flow. Scanning electron microscopy and immunohistochemistry verified a cellular lining and revealed a luminal monolayer of endothelial cells. After BVM development, bare metal stents were deployed. Stented and unstented BVMs were evaluated using fluorescent nuclear staining and optical coherence tomography (OCT). En face and cross-sectional evaluation of bisbenzimide-stained nuclei revealed cellular coverage of the stent surfaces. Cross-sectional evaluation using OCT also illustrated a cellular layer developing over the stent struts. These data support the use of TEVGs as in vitro BVMs for pre-clinical evaluation of the endothelial cell response to stents and endovascular devices.