Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, People's Republic of China.
Biomacromolecules. 2011 Aug 8;12(8):2914-24. doi: 10.1021/bm200479f. Epub 2011 Jun 30.
Endothelialization of vascular grafts prior to implantation has been investigated widely to enhance biocompatibility and antithrombogenicity. Thrombosis of artificial vessels is typically caused by platelet adhesion and agglomeration following endothelial cells detachment when exposed to the shear stress of blood circulation. The present study thus aimed at preventing platelet adhesion and aggregation onto biomaterials before the endothelial confluence is fully achieved. We report this modification of poly(lactic-co-glycolic acid) (PLGA) scaffolds, both to impart hemocompatibility to prevent platelet adhesion and aggregation before the endothelial confluence is fully achieved and to support EC growth to accelerate endothelialization. The modification was achieved by covalent immobilization of sulfated silk fibroin on PLGA scaffolds using γ irradiation. Using phosphate-buffered saline (PBS) as an aging medium, it was demonstrated that the scaffolds prepared by γ irradiation had a good retention of sulfated silk fibroin. The systematic in vitro hemocompatibility evaluation revealed that sulfated silk fibroin covalently immobilized PLGA (S-PLGA) scaffolds-reduced platelet adhesion and activation, prolonged whole blood clotting time, activated partial thromboplastin time (APTT), thrombin time (TT), and prothrombin time (PT). To evaluate further in vitro cytocompatibility of the scaffolds, we seeded vascular ECs on the scaffolds and cultured them for 2 weeks. The ECs were seen to attach and proliferate well on S-PLGA scaffolds, forming cell aggregates that gradually increased in size and fused with adjacent cell aggregates to form a monolayer covering the scaffold surface. Moreover, it was demonstrated through the gene transcript levels and the protein expressions of EC-specific markers that the cell functions of ECs on S-PLGA scaffolds were better preserved than those on PLGA scaffolds. Therefore, this study has described the generation of a vascular graft that possesses the unique ability to display excellent hemocompatibility while simultaneously supporting extensive endothelialization.
在植入血管移植物之前进行内皮化已被广泛研究，以增强生物相容性和抗血栓形成性。人工血管的血栓形成通常是由于血小板在暴露于血液循环的切变应力时与内皮细胞分离后粘附和聚集引起的。因此，本研究旨在在完全实现内皮细胞融合之前防止生物材料上的血小板粘附和聚集。我们报告了聚（乳酸-共-乙醇酸）（PLGA）支架的这种修饰，以赋予血液相容性，防止在完全实现内皮细胞融合之前血小板的粘附和聚集，并支持 EC 生长以加速内皮化。修饰是通过使用γ辐照将硫酸化丝素蛋白共价固定在 PLGA 支架上来实现的。使用磷酸盐缓冲盐水（PBS）作为老化介质，证明了通过γ辐照制备的支架具有良好的硫酸化丝素蛋白保留率。系统的体外血液相容性评价表明，共价固定硫酸化丝素蛋白的 PLGA（S-PLGA）支架可减少血小板的粘附和激活，延长全血凝固时间，激活部分凝血活酶时间（APTT），凝血酶时间（TT）和凝血酶原时间（PT）。为了进一步评估支架的体外细胞相容性，我们将血管内皮细胞（EC）接种在支架上并培养了 2 周。观察到 EC 在 S-PLGA 支架上很好地附着和增殖，形成细胞聚集体，这些聚集体逐渐增大并与相邻的细胞聚集体融合，形成覆盖支架表面的单层。此外，通过 EC 特异性标志物的基因转录水平和蛋白表达证明，S-PLGA 支架上 EC 的细胞功能比 PLGA 支架上更好地保留。因此，本研究描述了一种血管移植物的产生，该移植物具有同时展示出色的血液相容性和支持广泛内皮化的独特能力。
