Anderson Deirdre E J, McKenna Kathryn A, Glynn Jeremy J, Marzec Ulla, Hanson Stephen R, Hinds Monica T
Department of Biomedical Engineering, Oregon Health and Science University, Portland, Oreg., USA.
Cells Tissues Organs. 2014;199(4):238-48. doi: 10.1159/000368223. Epub 2015 Jan 16.
There is significant clinical need for viable small-diameter vascular grafts. While there are many graft biomaterials in development, few have been clinically successful. Evaluation of grafts with a clinically relevant model is needed to drive development. This work examined extracellular matrix coatings on the thrombotic phenotype of endothelial outgrowth cells (EOCs). EOCs were tested on flat plates and tubular grafts. Flat plate studies examined collagen I, collagen IV, fibronectin and α-elastin coatings. EOCs attached or proliferated more readily on collagen I and fibronectin surfaces as determined by total DNA. The production of activated protein C (APC) by EOCs was also dependent on the surface coating, with collagen I and fibronectin displaying a higher activity than both collagen IV and α-elastin on flat plate studies. Based on these results, only collagen I and fibronectin coatings were tested on expanded polytetrafluoroethylene (ePTFE) in the ex vivo model. Tubular samples showed significantly greater tissue factor pathway inhibitor gene expression on collagen I than on fibronectin. Platelet adhesion was not significantly different, but EOCs on collagen I produced significantly lower APC than on fibronectin, suggesting that differences exist between the flat plate and tubular cultures. Overall, while the hemostatic phenotype of EOCs displayed some differences, cell responses were largely independent of the matrix coating. EOCs adhered strongly to both fibronectin- and collagen-I-coated ePTFE grafts under ex vivo (100 ml/min) flow conditions suggesting the usefulness of this clinically relevant cell source, testing modality, and shunt model for future work examining biomaterials and cell conditioning before implantation.
临床上对可用的小口径血管移植物有很大需求。虽然有许多移植生物材料正在研发中，但临床成功的却很少。需要用具有临床相关性的模型来评估移植物，以推动其发展。这项工作研究了细胞外基质涂层对内皮祖细胞（EOC）血栓形成表型的影响。EOC在平板和管状移植物上进行了测试。平板研究检测了I型胶原蛋白、IV型胶原蛋白、纤连蛋白和α-弹性蛋白涂层。通过总DNA测定，EOC在I型胶原蛋白和纤连蛋白表面更容易附着或增殖。EOC产生活化蛋白C（APC）也取决于表面涂层，在平板研究中，I型胶原蛋白和纤连蛋白的活性高于IV型胶原蛋白和α-弹性蛋白。基于这些结果，在体外模型中仅对I型胶原蛋白和纤连蛋白涂层在膨体聚四氟乙烯（ePTFE）上进行了测试。管状样本显示I型胶原蛋白上的组织因子途径抑制基因表达明显高于纤连蛋白。血小板黏附没有显著差异，但I型胶原蛋白上的EOC产生的APC明显低于纤连蛋白上的EOC，这表明平板培养和管状培养之间存在差异。总体而言，虽然EOC的止血表型存在一些差异，但细胞反应在很大程度上与基质涂层无关。在体外（100毫升/分钟）流动条件下，EOC强烈黏附于纤连蛋白和I型胶原蛋白涂层的ePTFE移植物，这表明这种具有临床相关性的细胞来源、测试方式和分流模型对于未来在植入前检查生物材料和细胞预处理的工作是有用的。
