Department of Tissue Engineering & Textile Implants, AME-Helmholtz Institute for Biomedical Engineering, RWTH Aachen University, Aachen, Germany.
Tissue Eng Part A. 2012 Sep;18(17-18):1818-26. doi: 10.1089/ten.TEA.2011.0648. Epub 2012 Jun 7.
Percutaneous stenting of occluded peripheral vessels is a well-established technique in clinical practice. Unfortunately, the patency rates of small-caliber vessels after stenting remain unsatisfactory. The aim of the BioStent concept is to overcome in-stent restenosis by excluding the diseased vessel segment entirely from the blood stream, in addition to providing an intact endothelial cell layer.
The concept combines the principles of vascular tissue engineering with a self-expanding stent: casting of the stent within a cellularized fibrin gel structure, followed by bioreactor conditioning, allows complete integration of the stent within engineered tissue.
Small-caliber BioStents (Ø=6 mm; n=4) were produced by casting a nitinol stent within a thin fibrin/vascular smooth muscle cell (vSMC) mixture, followed by luminal endothelial cell seeding, and conditioning of the BioStent within a bioreactor system. The potential remodeling of the fibrin component into tissue was analyzed using routine histological methods. Scanning electron microscopy was used to assess the luminal endothelial cell coverage following the conditioning phase and crimping of the stent.
The BioStent was shown to be noncytotoxic, with no significant effect on cell proliferation. Gross and microscopic analysis revealed complete integration of the nitinol component within a viable tissue structure. Hematoxylin and eosin staining revealed a homogenous distribution of vSMCs throughout the thickness of the BioStent, while a smooth, confluent luminal endothelial cell lining was evident and not significantly affected by the crimping/release process.
The BioStent concept is a platform technology offering a novel opportunity to generate a viable, self-expanding stent structure with a functional endothelial cell lining. This platform technology can be transferred to different applications depending on the luminal cell lining required.
经皮腔内血管成形术治疗闭塞性周围血管是临床实践中一种成熟的技术。不幸的是，支架置入后小血管的通畅率仍不理想。BioStent 概念的目的是通过将病变血管段完全排除在血流之外，同时提供完整的内皮细胞层，来克服支架内再狭窄。
该概念将血管组织工程的原理与自扩张支架相结合：在细胞化纤维蛋白凝胶结构内铸造支架，然后进行生物反应器处理，使支架完全整合到工程组织中。
通过在薄纤维蛋白/血管平滑肌细胞（vSMC）混合物内铸造镍钛诺支架，随后进行内腔内皮细胞接种，并在生物反应器系统内对 BioStent 进行处理，制造出小口径 BioStent（Ø=6mm；n=4）。使用常规组织学方法分析纤维蛋白成分向组织转化的潜力。扫描电子显微镜用于评估处理阶段和支架卷曲后内腔内皮细胞的覆盖情况。
BioStent 被证明无细胞毒性，对细胞增殖没有显著影响。大体和显微镜分析显示，镍钛诺组件完全整合到具有活力的组织结构中。苏木精和伊红染色显示 vSMC 在整个 BioStent 厚度上均匀分布，而光滑、连续的内腔内皮细胞衬里是明显的，并且不受卷曲/释放过程的显著影响。
BioStent 概念是一种平台技术，为生成具有功能内皮细胞衬里的可行、自扩张支架结构提供了新的机会。这种平台技术可以根据所需的内腔细胞衬里转移到不同的应用中。
