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

Abstract

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 smalldiameter tissue engineering blood vessels.

Effect of NMDA Receptor Agonist and Antagonist on Spermatogonia Stem Cells Proliferation in 2- and 3- Dimensional Culture Systems

“…DTM hydrogel scaffolds contain laminin and collagen, which can regulate the proliferation of SSCs and so, the purity of SSCs increases [29,31]. The other constituents of DTM are GAGs which surround the Sertoli cells and Leydig cells and affect cell adhesion, and proliferation [32]. These results showed that DTM contains some growth factors which can maintain SSCs activity and gene expression.…”

Physical, Mechanical, and Biological Properties of Fibrin Scaffolds for Cartilage Repair

“…Histological staining can evaluate cell adhesion and proliferation inside the scaffold, as well as the presence of lymphocytes and phagocytes in the incision area, which are indicators of inflammation [ 4 ]. Some fibrin scaffolds [ 66 , 67 ] or fibrin mixed with other biomaterial are compatible in animal models; for example, scaffolds of fibrin/PLC (Wang et al, 2020), fibrin/polyurethane [ 68 ], fibrin/agarose [ 4 ] ( Table 3 ). There are other parameters in addition to cell proliferation and immune cells infiltration that may help to evaluate the biocompatibility of fibrin scaffolds such as absorption, vascularization, hemocompatibility, or surface wettability.…”

Electrospun nanofiber scaffold for vascular tissue engineering

“…However, fibrin alone lacks the mechanical strength needed for use in TEVGs [98]. To take advantage of the excellent biological properties of fibrin, Yang et al [100] constructed a TEVG using a blend of electrospun fibrin and PU to provide mechanical support. PU was dissolved in a mix of tetrahydrofuran (THF) and dimethylformamide (DMF) and fibrin was dissolved in formic acid to prepare PU/fibrin blends of 5:95, 15:85, and 25:75.…”