Nanofiber vascular grafts have been shown to create neovessels made of autologous tissue, by in vivo scaffold biodegradation over time. However, many studies on graft materials and biodegradation have been conducted in vitro or in small animal models, instead of large animal models, which demonstrate different degradation profiles. In this study, we compared the degradation profiles of nanofiber vascular grafts in a rat model and a sheep model, while controlling for the type of graft material, the duration of implantation, fabrication method, type of circulation (arterial/venous), and type of surgery (interposition graft). We found that there was significantly less remaining scaffold (i.e., faster degradation) in nanofiber vascular grafts implanted in the sheep model compared with the rat model, in both the arterial and the venous circulations, at 6 months postimplantation. In addition, there was more extracellular matrix deposition, more elastin formation, more mature collagen, and no calcification in the sheep model compared with the rat model. In conclusion, studies comparing degradation of vascular grafts in large and small animal models remain limited. For clinical translation of nanofiber vascular grafts, it is important to understand these differences.

中文翻译：

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大小动物模型中纳米纤维血管移植物的不同降解速率。

已经显示出纳米纤维血管移植物通过随着时间的体内支架生物降解而产生由自体组织制成的新血管。然而，许多关于移植物材料和生物降解的研究已在体外或在小型动物模型中进行，而不是在大型动物模型中进行，这证明了不同的降解特性。在这项研究中，我们比较了大鼠模型和绵羊模型中纳米纤维血管移植物的降解情况，同时控制了移植物材料的类型，植入的持续时间，制造方法，循环类型（动脉/静脉）和类型手术（介入移植）。我们发现，与大鼠模型相比，绵羊模型中植入的纳米纤维血管移植物在动脉和静脉循环中的剩余支架（即更快的降解）显着减少，植入后6个月。此外，与大鼠模型相比，绵羊模型中细胞外基质沉积更多，弹性蛋白形成更多，胶原蛋白更成熟且没有钙化。总之，在大型和小型动物模型中比较血管移植物降解的研究仍然有限。对于纳米纤维血管移植物的临床翻译，重要的是要了解这些差异。