Bos H M, de Boer R A, Burns G L, Mohammad S F
Artificial Heart Research Laboratory, University of Utah, Salt Lake City 84103-1414, USA.
ASAIO J. 1996 Sep-Oct;42(5):M881-4. doi: 10.1097/00002480-199609000-00118.
This study was undertaken to investigate the possible association between thrombosis and infection using an in vitro test model in which fresh bovine blood was recirculated through test conduits (3.5 mm inner diameter) containing stent-like devices. Anticoagulation was adjusted so that the recirculating blood deposited thrombi on the stent to cause gradual occlusion, thus impeding the flow. Four stent-like devices were placed in separate conduits in each experiment, and blood was recirculated with the help of pneumatically driven ventricles. Flow through these conduits was monitored by ultrasonic flow detection. To quantitate bacterial interaction with thrombi, Staphylococcus epidermidis (15E10(9)) was labeled with 111Indium-oxine and added to the blood. Experiments lasted until the flow in the test conduits dropped to 10% of the starting flow. During this recirculation, as flow gradually decreased, one stent was taken out when flow was still at 100%, the second at 75%, the third at 50%, and the fourth at 10% of the starting flow. The number of bacteria associated with the thrombus was measured by gamma counting. The following observations were made: 1) the amount of thrombus increased with time in all experiments (this was confirmed in separate experiments by using autologous 111Indium labeled platelets); 2) bacterial adhesion showed a concomitant increase as thrombus size increased (this was confirmed by using 111Indium labeled bacteria), and 3) bacterial incorporation into the thrombus occurred regardless of whether they were viable or pretreated with the antibiotic rifampin. These observations suggest that as thrombi develop, they may preferentially attract micro-organisms. This suggests that devices with adherent thrombi may have greater susceptibility for infection.
本研究旨在利用体外测试模型，研究血栓形成与感染之间可能存在的关联。该模型中，新鲜牛血通过含有支架样装置的测试导管（内径3.5毫米）进行再循环。调整抗凝状态，使再循环血液在支架上形成血栓，导致逐渐阻塞，从而阻碍血流。每次实验中，四个支架样装置分别置于单独的导管中，借助气动心室使血液再循环。通过超声血流检测监测这些导管中的血流。为了定量细菌与血栓的相互作用，将表皮葡萄球菌（15E10(9)）用111铟 - 奥辛标记并添加到血液中。实验持续进行，直至测试导管中的血流降至起始血流的10%。在这个再循环过程中，随着血流逐渐减少，当血流仍为100%时取出一个支架，血流为75%时取出第二个，血流为50%时取出第三个，血流为10%时取出第四个。通过γ计数测量与血栓相关的细菌数量。得出以下观察结果：1）在所有实验中，血栓量随时间增加（通过使用自体111铟标记血小板的单独实验得到证实）；2）随着血栓尺寸增大，细菌黏附随之增加（通过使用111铟标记细菌得到证实）；3）无论细菌是活的还是用抗生素利福平预处理过的，都发生了细菌融入血栓的情况。这些观察结果表明，随着血栓形成，它们可能优先吸引微生物。这表明带有附着血栓的装置可能对感染更易感。
