Purpose: The development of tissue-engineered blood vessels provides a new source of donors for coronary artery bypass grafting and peripheral blood vessel transplantation. Fibrin fiber has good biocompatibility and is an ideal tissue engineering vascular scaffold, but its mechanical property needs improvement.
Methods: We mixed polyurethane (PU) and fibrin to prepare the PU/fibrin vascular scaffolds by using electrospinning technology in order to enhance the mechanical properties of fibrin scaffold. We investigated the morphological, mechanical strength, hydrophilicity, degradation, blood and cell compatibility of PU/fibrin (0:100), PU/fibrin (5:95), PU/fibrin (15:85) and PU/fibrin (25:75) vascular scaffolds. Based on the results in vitro, PU/fibrin (15:85) was selected for transplantation in vivo to repair vascular defects, and the extracellular matrix formation, vascular remodeling, and immune response were evaluated.
Results: The results indicated that the fiber diameter of the PU/fibrin (15:85) scaffold was about 712nm. With the increase of PU content, the mechanical strength of the composite scaffolds increased, however, the degradation rate decreased gradually. The PU/fibrin scaffold showed good hydrophilicity and hemocompatibility. PU/fibrin (15:85) vascular scaffold could promote the adhesion and proliferation of mesenchymal stromal cells (MSCs). Quantitative RT-PCR experimental results showed that the expression of collagen, survivin and vimentin genes in PU/fibrin (15:85) was higher than that in PU/fibrin (25:75). The results in vivo indicated the mechanical properties and compliance of PU/fibrin grafts could meet clinical requirements and the proportion of thrombosis or occlusion was significantly lower. The graft showed strong vasomotor response, and the smooth muscle cells, endothelial cells, and ECM deposition of the neoartery were comparable to that of native artery after 3 months. At 3 months, the amount of macrophages in PU/fibrin grafts was significantly lower, and the secretion of pro-inflammatory and anti-inflammatory cytokines decreased.
Conclusion: PU/fibrin (15:85) vascular scaffolds had great potential to be used as small-diameter tissue engineering blood vessels.

Keywords: PU/fibrin scaffold, small diameter, in vitro biocompatibility, biomechanical properties, vascular remodeling


中文翻译：

---

具有良好生物力学性能的PU/纤维蛋白血管支架的制备及其体内外性能评价

目的：组织工程血管的发展为冠状动脉搭桥术和外周血管移植提供了新的供体来源。纤维蛋白纤维具有良好的生物相容性，是理想的组织工程血管支架，但其力学性能有待提高。
方法：采用静电纺丝技术将聚氨酯（PU）与纤维蛋白混合制备PU/纤维蛋白血管支架，以提高纤维蛋白支架的力学性能。我们研究了 PU/纤维蛋白 (0:100)、PU/纤维蛋白 (5:95)、PU/纤维蛋白 (15:85) 和 PU/纤维蛋白 (25:85) 的形态、机械强度、亲水性、降解、血液和细胞相容性。 75）血管支架。根据体外结果，选择PU/纤维蛋白（15：85）进行体内移植修复血管缺损，并评估细胞外基质形成、血管重塑和免疫反应。
结果：结果显示PU/纤维蛋白(15:85)支架的纤维直径约为712nm。随着PU含量的增加，复合支架的机械强度增加，但降解率逐渐下降。PU/纤维蛋白支架表现出良好的亲水性和血液相容性。PU/纤维蛋白（15:85）血管支架可以促进间充质基质细胞（MSCs）的粘附和增殖。定量RT-PCR实验结果显示，PU/纤维蛋白(15:85)中胶原蛋白、生存素和波形蛋白基因的表达量高于PU/纤维蛋白(25:75)。体内结果表明PU/纤维蛋白移植物的力学性能和顺应性满足临床要求，血栓或闭塞的比例显着降低。移植物表现出强烈的血管舒缩反应，3个月后新动脉的平滑肌细胞、内皮细胞和ECM沉积与天然动脉相当。3个月时，PU/纤维蛋白移植物中巨噬细胞的数量明显降低，促炎和抗炎细胞因子的分泌减少。
结论： PU/纤维蛋白（15:85）血管支架作为小直径组织工程血管具有巨大的潜力。

关键词： PU/纤维蛋白支架，小直径，体外生物相容性，生物力学性能，血管重塑