School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva CH-1211, Switzerland.
Biomaterials. 2012 Jan;33(1):38-47. doi: 10.1016/j.biomaterials.2011.09.024. Epub 2011 Sep 21.
In the active field of vascular graft research, polycaprolactone is often used because of its good mechanical strength and its biocompatibility. It is easily processed into micro and nano-fibers by electrospinning to form a porous, cell-friendly scaffold. However, long term in vivo performance of polycaprolactone vascular grafts had yet to be investigated. In this study, polycaprolactone micro and nano-fiber based vascular grafts were evaluated in the rat abdominal aorta replacement model for 1.5, 3, 6, 12, and 18 months (n = 3 for each time point). The grafts were evaluated for patency, thrombosis, compliance, tissue regeneration, and material degradation. Results show excellent structural integrity throughout the study, with no aneurysmal dilation, and perfect patency with no thrombosis and limited intimal hyperplasia. Endothelialization, cell invasion, and neovascularization of the graft wall rapidly increased until 6 months, but at 12 and 18 months, a cellular regression is observed. On the medium term, chondroid metaplasia takes place in the intimal hyperplasia layers, which contributes to calcification of the grafts. This study presents issues with degradable vascular grafts that cannot be identified with short implantation times or in vitro studies. Such findings should allow for better design of next generation vascular grafts.
在血管移植物研究的活跃领域，聚己内酯因其良好的机械强度和生物相容性而被广泛应用。它可以通过静电纺丝很容易地加工成微纳米纤维，形成多孔、细胞友好的支架。然而，聚己内酯血管移植物的长期体内性能仍有待研究。在这项研究中，使用大鼠腹主动脉置换模型评估了基于聚己内酯微纳米纤维的血管移植物在 1.5、3、6、12 和 18 个月（每个时间点 3 个样本）时的通畅性、血栓形成、顺应性、组织再生和材料降解情况。结果显示，在整个研究过程中，移植物具有出色的结构完整性，没有动脉瘤扩张，并且保持着完美的通畅性，没有血栓形成和有限的内膜增生。移植物壁的内皮化、细胞浸润和新血管生成在 6 个月内迅速增加，但在 12 个月和 18 个月时，观察到细胞退化。从中期来看，内膜增生层发生软骨样化生，这导致移植物的钙化。本研究提出了一些问题，即对于可降解血管移植物，仅通过短期植入或体外研究无法识别这些问题。这些发现将有助于更好地设计下一代血管移植物。
