El-Kurdi Mohammed S, Hong Yi, Stankus John J, Soletti Lorenzo, Wagner William R, Vorp David A
Department of Surgery, University of Pittsburgh, Pittsburgh, PA, 15219, United States; Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, 15219, United States.
Biomaterials. 2008 Aug;29(22):3213-20. doi: 10.1016/j.biomaterials.2008.04.009. Epub 2008 May 2.
Arterial vein grafts (AVGs) often fail due to intimal hyperplasia, thrombosis, or accelerated atherosclerosis. Various approaches have been proposed to address AVG failure, including delivery of temporary mechanical support, many of which could be facilitated by perivascular placement of a biodegradable polymer wrap. The purpose of this work was to demonstrate that a polymer wrap can be applied to vein segments without compromising viability/function, and to demonstrate one potential application, i.e., gradually imposing the mid-wall circumferential wall stress (CWS) in wrapped veins exposed to arterial levels of pressure. Poly(ester urethane)urea, collagen, and elastin were combined in solution, and then electrospun onto freshly-excised porcine internal jugular vein segments. Tissue viability was assessed via Live/Dead staining for necrosis, and vasomotor challenge with epinephrine and sodium nitroprusside for functionality. Wrapped vein segments were also perfused for 24h within an ex vivo vascular perfusion system under arterial conditions (pressure = 120/80 mmHg; flow = 100 mL/min), and CWS was calculated every hour. Our results showed that the electrospinning process had no deleterious effects on tissue viability, and that the mid-wall CWS vs. time profile could be dictated through the composition and degradation of the electrospun wrap. This may have important clinical applications by enabling the engineering of an improved AVG.
动静脉移植物(AVG)常常因内膜增生、血栓形成或动脉粥样硬化加速而失效。人们已经提出了各种方法来解决AVG失效问题,包括提供临时机械支持,其中许多方法可通过在血管周围放置可生物降解的聚合物包裹物来实现。这项工作的目的是证明聚合物包裹物可以应用于静脉段而不损害其活力/功能,并证明一种潜在的应用,即在暴露于动脉压力水平的包裹静脉中逐渐施加中膜圆周壁应力(CWS)。将聚(酯脲)脲、胶原蛋白和弹性蛋白在溶液中混合,然后静电纺丝到新鲜切除的猪颈内静脉段上。通过用于检测坏死的活/死染色以及用于检测功能的肾上腺素和硝普钠血管舒缩刺激来评估组织活力。包裹的静脉段还在体外血管灌注系统中于动脉条件下(压力=120/80 mmHg;流量=100 mL/min)灌注24小时,并且每小时计算一次CWS。我们的结果表明,静电纺丝过程对组织活力没有有害影响,并且中膜CWS随时间的变化曲线可以通过静电纺丝包裹物的组成和降解来控制。这通过实现改进的AVG的工程化可能具有重要的临床应用。