Assessment of the Intimal Response to a Protein-Modified Stent in a Tissue-Engineered Blood Vessel Mimic

Abstract

Protein-coated intravascular stents have emerged as potential pro-healing modifications for or alternatives to anti-proliferative drug-eluting stents. To support the development of these devices, preclinical testing is required to evaluate the intimal response to new coatings and modifications. The purpose of this work was to implement a tissue-engineered blood vessel as an in vitro testing system to evaluate extracellular matrix-modified stents with regard to endothelialization of the stent surface. Stents were modified by submersion in a protein-enriched medium and were subsequently deployed within tissue-engineered blood vessels and cultivated in vitro under flow to assess the intimal response. Scanning electron microscopy, fluorescent nuclear staining with en face imaging, and histological assessments were performed 7 or 14 days postdeployment. Results illustrated accelerated cellular regeneration over protein-modified stent strut surfaces, with increased coverage and increased tissue thickness atop protein-modified stent struts. In addition, the intimal response to modified stents differed significantly from bare metal stents. Conclusions from this work support the use of a tissue-engineered blood vessel mimic system for evaluation of modified stent surfaces. These findings are important to stent researchers as well as laboratories developing tissue-engineered constructs.