PROTEIN AND THROMBUS DEPOSITION ON VASCULAR GRAFTS

在血液-聚合物界面处血栓形成的发生呈现出主要的 小直径人造板开发中的设计难点 血管移植物 血液和人造表面之间的相互作用 导致吸附蛋白质层， 沉积和血栓形成。 决定其性质的因素 这个蛋白质层的结构并不明确。 我们已经确定， 表面的化学性质和蛋白质吸附的条件 影响血栓形成量和栓塞率。 我们建议在分子水平上研究表面蛋白质的相互作用。 市售和实验室合成的生物材料， 将在体外使用明显不同的化学表面性质， 犬离体实验研究化学修饰的影响 蛋白质沉积的特性。 人或犬的体外沉积 纤维蛋白原、纤连蛋白、玻连蛋白和血清白蛋白 材料将被评估。 这些蛋白质将被单独吸附， 竞争性地，顺序地检查蛋白质-蛋白质相互作用， 表面。 吸附蛋白的构象将通过以下方法测定： 傅立叶变换红外光谱法和酶法。 将通过以下方法评估吸附蛋白的方向和分布： 免疫学方法。 此外，犬蛋白质将 预吸附到材料上，并在犬离体分流器中进行测试， 在不存在抗凝剂的情况下测定全血反应。 蛋白质构象、取向和分布对 将检查血小板活化。 扫描和高压电子 显微镜将用于评估形态学和细胞骨架的变化， 血小板 视频增强显微镜将用于测量颗粒 由蛋白质-表面相互作用诱导的分泌。 这些研究将扩展目前对相关机制的研究 在人工表面诱导血栓形成中， 将有助于生物材料的设计。

The occurrence of thrombosis at a blood-polymer interface presents major design difficulties in the development of small-diameter artificial vascular grafts. The interaction between blood and an artificial surface results in an adsorbed protein layer which affects the extent of platelet deposition and thrombus formation. The factors that determine the nature of this protein layer are not well-defined. We have determined that both the chemical nature of the surface and the conditions of protein adsorption influence the amount of thrombus formation and rate of embolization. We propose to study surface-protein interactions at the molecular level. Commercially-available and laboratory-synthesized biomaterials which have markedly different chemical surface properties will be used in in vitro and canine ex vivo experiments to study the effect of modifications in chemical properties on protein deposition. In vitro deposition of human or canine fibrinogen, fibronectin, vitronectin, and serum albumin onto these materials will be assessed. These proteins will be adsorbed singly, competitively, and sequentially to examine protein-protein interactions on the surfaces. Conformation of the adsorbed protein will be determined by Fourier Transform Infrared spectroscopy and by enzymatic methods. Orientation and distribution of adsorbed proteins will be assessed by immunological methods. In addition, the canine proteins will be preadsorbed onto the materials and tested in the canine ex vivo shunt to determine the whole-blood response in the absence of anticoagulants. The influence of protein conformation, orientation, and distribution on platelet activation will be examined. Scanning and high voltage electron microscopy will be used to assess morphological and cytoskeletal changes in platelets. Video-enhanced microscopy will be used to measure the granule secretion induced by the protein-surface interaction. These studies will extend the current research on the mechanisms involved in artificial surface-induced thrombogenesis and provide information that will aid in the design of biomaterials.