Department of Biomedical Engineering, Boston University, Boston, Massachusetts.
Division of Materials Science and Engineering, Boston University, Boston, Massachusetts.
J Biomed Mater Res B Appl Biomater. 2020 Aug;108(6):2441-2449. doi: 10.1002/jbm.b.34576. Epub 2020 Feb 4.
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.
尽管在工程大、小直径动脉修复或旁路的血管移植物方面已经取得了很大进展，但将这些结果扩展到显微外科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 1mm，内径 0.5mm）作为中间移植物用于刘易斯大鼠股动脉的血管显微外科。这些管是通过在芯轴周围脱水管状胶原凝胶，用京尼平交联，接种同源内皮细胞，然后通过缝合吻合进行植入前培养而形成的。在模拟手术处理后，管内保持连续内皮衬里的能力强烈依赖于交联剂浓度和培养时间。优化的制备条件可使约 80%的管在模拟手术处理后保留内皮，约 40%的移植物在植入后 7 天保持通畅。组织学分析显示在植入物的内表面和外表面形成肉芽组织和 CD31 阳性结构。这项研究提供了一个原理证明，即内皮化的致密胶原管在血管显微外科后最长可保持 7 天的通畅，并表明轻度支架交联对于维持牢固的内皮黏附非常重要。
