Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran.
Institute for Nano-science and Nano-technology, Sharif University of Technology, Tehran, Iran.
Sci Rep. 2017 Jun 30;7(1):4455. doi: 10.1038/s41598-017-04510-1.
Autologous grafts, as the gold standard for vascular bypass procedures, associated with several problems that limit their usability, so tissue engineered vessels have been the subject of an increasing number of works. Nevertheless, gathering all of the desired characteristics of vascular scaffolds in the same construct has been a big challenge for scientists. Herein, a composite silk-based vascular scaffold (CSVS) was proposed to consider all the mechanical, structural and biological requirements of a small-diameter vascular scaffold. The scaffold's lumen composed of braided silk fiber-reinforced silk fibroin (SF) sponge covalently heparinized (H-CSVS) using Hydroxy-Iron Complexes (HICs) as linkers. The highly porous SF external layer with pores above 60 μm was obtained by lyophilization. Silk fibers were fully embedded in scaffold's wall with no delamination. The H-CSVS exhibited much higher burst pressure and suture retention strength than native vessels while comparable elastic modulus and compliance. H-CSVSs presented milder hemolysis in vitro and significant calcification resistance in subcutaneous implantation compared to non-heparinized ones. The in vitro antithrombogenic activity was sustained for over 12 weeks. The cytocompatibility was approved using endothelial cells (ECs) and vascular smooth muscle cells (SMCs) in vitro. Therefore, H-CSVS demonstrates a promising candidate for engineering of small-diameter vessels.
自体移植物是血管旁路手术的金标准，但存在一些限制其可用性的问题，因此组织工程血管已成为越来越多研究的主题。然而，将血管支架的所有理想特性都集中在同一结构中一直是科学家们面临的一个巨大挑战。在此，提出了一种基于丝素的复合血管支架（CSVS），以满足小直径血管支架的所有机械、结构和生物学要求。支架的管腔由编织丝纤维增强丝素（SF）海绵组成，使用羟基铁复合物（HICs）作为连接物进行共价肝素化（H-CSVS）。通过冷冻干燥获得具有 60μm 以上孔径的高多孔 SF 外层。丝纤维完全嵌入支架壁中，没有分层。与天然血管相比，H-CSVS 的爆裂压力和缝线保持强度要高得多，而弹性模量和顺应性相当。与非肝素化支架相比，H-CSVS 在皮下植入时具有更轻微的体外溶血和显著的抗钙化能力。体外抗血栓形成活性可持续超过 12 周。体外细胞相容性实验使用内皮细胞（ECs）和血管平滑肌细胞（SMCs）进行了验证。因此，H-CSVS 是一种很有前途的小直径血管工程候选材料。
