Baumgartner J N, Cooper S L
Department of Chemical Engineering, University of Delaware, Newark 19716, USA.
ASAIO J. 1996 Sep-Oct;42(5):M476-9. doi: 10.1097/00002480-199609000-00033.
Thrombosis and infection are two major complications associated with cardiovascular devices such as ventricular assist devices, total artificial hearts, vascular grafts, and catheters. When blood contacts an artificial biomaterial, protein deposition occurs, as do activation of the blood coagulation cascade, platelet adhesion, activation, and aggregation, all of which lead to thrombus formation. An increased incidence of bacterial infection also has been seen clinically with indwelling biomaterial devices. Some evidence suggests a possible association between thrombosis and infection, in that adherent bacteria may provide a nidus for thrombus formation, or adherent thrombi composed of platelets and fibrin may form sheltered sites for bacterial adhesion. In the current study, the authors examined Staphylococcus aureus adhesion to sulfonated, aminated, and phosphonated polyurethane surfaces that had been pre-adsorbed with solutions of increasing complexity, in an effort to approach and simulate clot formation on the surface. These solutions included various combinations of fibrinogen, albumin, plasma, thrombin, and isolated platelets. Bacterial adhesion was observed in a radial flow chamber mounted on the motorized stage of a video microscopy system, with image processing software used to perform automated data collection and image analysis. Scanning electron microscopy also was used to visualize cross-linked fibrin and bacterial adhesion on these surfaces. Bacterial adhesion was found to be lowest on the phosphonated polyurethane. The presence of fibrin or isolated platelets significantly increased bacterial adhesion compared to surfaces pre-adsorbed with albumin.
血栓形成和感染是与心血管装置相关的两大主要并发症，这些装置包括心室辅助装置、全人工心脏、血管移植物和导管。当血液与人工生物材料接触时，会发生蛋白质沉积，同时血液凝固级联反应被激活、血小板黏附、活化和聚集，所有这些都会导致血栓形成。临床上也发现，留置生物材料装置会使细菌感染的发生率增加。一些证据表明血栓形成与感染之间可能存在关联，因为黏附的细菌可能为血栓形成提供病灶，或者由血小板和纤维蛋白组成的黏附血栓可能为细菌黏附形成庇护场所。在本研究中，作者检测了金黄色葡萄球菌在磺化、胺化和膦酸化聚氨酯表面的黏附情况，这些表面预先吸附了复杂性不断增加的溶液，以接近和模拟表面的凝血形成。这些溶液包括纤维蛋白原、白蛋白、血浆、凝血酶和分离的血小板的各种组合。在安装在视频显微镜系统电动载物台上的径向流动腔中观察细菌黏附情况，使用图像处理软件进行自动数据收集和图像分析。扫描电子显微镜也用于观察这些表面上交联的纤维蛋白和细菌黏附情况。发现细菌在膦酸化聚氨酯上的黏附最少。与预先吸附白蛋白的表面相比，纤维蛋白或分离的血小板的存在显著增加了细菌黏附。
