Evaluation of Human Endothelial Cells Post Stent Deployment in a Cardiovascular Simulator In Vitro

Abstract

Percutaneous stent implantation has revolutionized the clinical treatment of occluded arteries. Nevertheless, there is still a large unmet need to prevent re-occlusion after implantation. Consequently, a niche exists for a cost-effective pre-clinical method of evaluating novel interventional devices in human models. Therefore, the development of a coronary model artery offers tremendous potential for the treatment of endothelial cell dysfunction and restenosis. As a first step, we employ tissue-engineering principles to examine the effect of stent deployment upon endothelial cells in a tubular in vitro system capable of replicating the coronary artery biomechanical environment. In particular, the cellular and molecular changes pertaining to inflammation, proliferation, and death were assessed after stent deployment. Real-time quantitative PCR demonstrated increased expression of genes encoding for E-Selectin, ICAM-1, and VCAM-1; markers associated with an inflammatory response in vivo. Further, an increase in the pro-apoptotic protein Bax was paralleled with a decrease in the anti-apoptotic protein Bcl-2; however, apoptotic morphology was not observed. Interestingly, transcription of c-fos increased, whereas Ki67 levels fell over the same period. One hypothesis is that these results are in response to the altered local hemodynamic environment induced by stent deployment. Most significantly, this study highlights the potential of a biomimetic hemodynamic bioreactor combined with a gene expression analysis to evaluate, with greater specificity, the performance and interaction of stents with the endothelial layer in a controlled environment.

Comparison of in vitro human endothelial cell response to self-expanding stent deployment in a straight and curved peripheral artery simulator

“…The bioreactor used in this study was adapted from a previous bioreactor perfusion system designed to deliver combinational forces of coronary arterial distention, pressure, flow and WSS to pseudovessels-specially fabricated using silicone tubes seeded with a monolayer of ECs [44]. For the study presented here, the existing bioreactor design was augmented to simulate peripheral arterial radial distention, pressure, flow and mean WSS and to incorporate both straight and curved artery configurations.…”

“…Sterilized silicone tubes were coated with 8 mg ml 21 fibronectin (Sigma) and seeded with human umbilical vein endothelial cells (HUVECs) between passages 4 and 6 (PromoCell). HUVECs were seeded at a concentration of 171 500 cells cm 22 in EC growth medium (C-22010PromoCell) [44]. Tubes were rotated at slow rotation speed (10 rph) for 48 h (378C, 5% CO 2 ).…”

Comparative Assessment of Transient Exposure of Paclitaxel or Zotarolimus on In Vitro Vascular Cell Death, Proliferation, Migration, and Proinflammatory Biomarker Expression

“…Proinflammatory cytokines and cellular adhesion molecules have previously been implicated in recruitment of leukocytes contributing to restenosis. [22][23][24][25][26][27][28][29][30] By limiting the secretion of proinflammatory cytokines (such as interleukins and RANTES) in cells of injured tissue, fewer leukocytes are expected to be recruited to aid in the patchwork repair of lesions. Similarly, reduction of translocation of adhesion molecules such as VCAM-1 to the surface of endothelium is expected to reduce the number of extravasated leukocytes.…”

Device-Based In Vitro Techniques for Mechanical Stimulation of Vascular Cells: A Review

“…As with explanted vessel studies, a constant axial stretch may be applied to simulate in vivo conditions [131,149]. When applying cells to a silicone mock artery, the inner surface is treated with fibronectin to allow cell attachment [131,149,[152][153][154]161,164,170]. Hydrophilizing the mock artery with sulfuric acid before applying fibronectin is a common method [131,149,152,154] which improves cell adhesion [170].…”

“…Materials used to construct the mock artery include PVA cryogel [170], silicone elastomers [136,153,161,166], and 3D PLCL scaffolds [157]. Sylgard V R 184 (Dow Corning, Midland, MI), a commercially available silicone elastomer, has been used several times in mock artery applications [131,149,152,154,170].…”