Preparation of PU/Fibrin Vascular Scaffold with Good Biomechanical Properties and Evaluation of Its Performance in vitro and in vivo

Lei Yang,1,2,* Xiafei Li,3,* Yiting Wu,4 Pengchong Du,1,5 Lulu Sun,1 Zhenyang Yu,2 Shuang Song,1 Jianshen Yin,1 Xianfen Ma,1 Changqin Jing,1 Junqiang Zhao,3 Hongli Chen,1 Yuzhen Dong,2 Qiqing Zhang,1 Liang Zhao1,6,7 1College of Life Science and Technology, Xinxiang Medical University, Xinxiang, People’s Republic of China; 2Department of Orthopedics, First Affiliated Hospital, Xinxiang Medical University, Xinxiang, People’s Republic of China; 3College of Medical Engineering, Xinxiang Medical University, Xinxiang, People’s Republic of China; 4Xiacun Community Health Service Center, Shenzhen Hospital, University of Chinese Academy of Sciences, Shenzhen, People’s Republic of China; 5Department of Cardio-Thoracic Surgery, Third Affiliated Hospital, Xinxiang Medical University, Xinxiang, People’s Republic of China; 6Key Laboratory of Cardiac Structure Research, Zhengzhou Seventh People’s Hospital, Zhengzhou, People’s Republic of China; 7The Central Lab, The Third People’s Hospital of Datong, Datong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Liang Zhao; Yuzhen Dong Email zhaoliang4321@163.com; dongyuzhen1998@163.comPurpose: 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