Fercana George, Bowser Devon, Portilla Margarita, Langan Eugene M, Carsten Christopher G, Cull David L, Sierad Leslie N, Simionescu Dan T
1 Biocompatibility and Tissue Regeneration Laboratories, Department of Bioengineering, Clemson University , Clemson, South Carolina.
Tissue Eng Part C Methods. 2014 Dec;20(12):1016-27. doi: 10.1089/ten.TEC.2014.0047. Epub 2014 Sep 29.
The aim of this study was to generate extended length, small diameter vascular scaffolds that could serve as potential grafts for treatment of acute ischemia. Biological tissues are considered excellent scaffolds, which exhibit adequate biological, mechanical, and handling properties; however, they tend to degenerate, dilate, and calcify after implantation. We hypothesized that chemically stabilized acellular arteries would be ideal scaffolds for development of vascular grafts for peripheral surgery applications. Based on promising historical data from our laboratory and others, we chose to decellularize bovine mammary and femoral arteries and test them as scaffolds for vascular grafting. Decellularization of such long structures required development of a novel "bioprocessing" system and a sequence of detergents and enzymes that generated completely acellular, galactose-(α1,3)-galactose (α-Gal) xenoantigen-free scaffolds with preserved collagen, elastin, and basement membrane components. Acellular arteries exhibited excellent mechanical properties, including burst pressure, suture holding strength, and elastic recoil. To reduce elastin degeneration, we treated the scaffolds with penta-galloyl glucose and then revitalized them in vitro using a tunic-specific cell approach. A novel atraumatic endothelialization protocol using an external stent was also developed for the long grafts and cell-seeded constructs were conditioned in a flow bioreactor. Both decellularization and revitalization are feasible but cell retention in vitro continues to pose challenges. These studies support further efforts toward clinical use of small diameter acellular arteries as vascular grafts.
本研究的目的是制备长度更长、直径更小的血管支架，作为治疗急性缺血的潜在移植物。生物组织被认为是优良的支架，具有足够的生物学、力学和操作性能；然而，它们在植入后往往会发生退变、扩张和钙化。我们假设化学稳定的脱细胞动脉将是用于外周手术的血管移植物开发的理想支架。基于我们实验室和其他实验室的有前景的历史数据，我们选择对牛乳腺动脉和股动脉进行脱细胞处理，并将它们作为血管移植的支架进行测试。对如此长的结构进行脱细胞处理需要开发一种新型的“生物加工”系统以及一系列去污剂和酶，以生成完全无细胞、无半乳糖-(α1,3)-半乳糖（α-Gal）异种抗原且保留胶原、弹性蛋白和基底膜成分的支架。脱细胞动脉表现出优异的力学性能，包括爆破压力、缝线握持强度和弹性回缩。为了减少弹性蛋白退变，我们用五倍子酰葡萄糖处理支架，然后使用特定于内膜的细胞方法在体外使其恢复活力。还为长移植物开发了一种使用外部支架的新型无创内皮化方案，并将接种细胞的构建体置于流动生物反应器中进行处理。脱细胞处理和恢复活力都是可行的，但体外细胞保留仍然是一个挑战。这些研究支持进一步努力将小直径脱细胞动脉作为血管移植物用于临床。
