Although much progress has been made in engineering vascular grafts for large‐ and small‐diameter arterial repair or bypass, the extension of these results to the microsurgical size scale has been challenging. Here, we evaluated the use of dense collagen tubes (outer diameter 1 mm, inner diameter 0.5 mm) for vascular microsurgery as interpositional grafts to the femoral artery of Lewis rats. These tubes were formed by dehydrating tubular collagen gels around a mandrel, crosslinking them with genipin, seeding with syngeneic endothelial cells, and culturing before implantation by suture anastomosis. The retention of a confluent endothelial lining inside the tubes after mock surgical handling depended strongly on the crosslinker concentration and culture time. Optimized preparation conditions enabled retention of endothelium after mock surgical handling in ~80% of tubes and maintenance of patency 7 days after implantation in ~40% of grafts. Histological analysis showed the development of granulation tissue and the presence of CD31‐positive structures on the inner and outer surfaces of implants. This study provides a proof‐of‐principle demonstration that endothelialized dense collagen tubes can remain patent for up to 7 days after vascular microsurgery, and points to the importance of mild scaffold crosslinking for maintaining firm endothelial adhesion.

中文翻译：

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血管显微手术中直径为 1 毫米的内皮化致密胶原管的评估。

尽管在用于大直径和小直径动脉修复或旁路的工程血管移植方面取得了很大进展，但将这些结果扩展到显微外科尺寸规模一直具有挑战性。在这里，我们评估了使用致密胶原管（外径 1 毫米，内径 0.5 毫米）在血管显微手术中作为路易斯大鼠股动脉的插入移植物。这些管是通过使心轴周围的管状胶原凝胶脱水、将它们与京尼平交联、接种同基因内皮细胞并在通过缝合吻合术植入前培养而形成的。模拟手术处理后管内融合内皮衬里的保留在很大程度上取决于交联剂浓度和培养时间。优化的准备条件能够在模拟手术处理后保留约 80% 的管内皮，并在约 40% 的移植物植入后 7 天保持通畅。组织学分析显示肉芽组织的发育和植入物内表面和外表面存在 CD31 阳性结构。该研究提供了一个原理验证证明，血管显微手术后内皮化的致密胶原管可以保持通畅长达 7 天，并指出温和的支架交联对于维持牢固的内皮粘附的重要性。