MECHANISM OF SICKLE ERYTHROCYTE/ENDOTHELIAL ADHESION

镰状红细胞/内皮粘附机制

• 批准号: 3473155
• 负责人: TIMOTHY M WICK
• 金额: $ 9.73万
• 依托单位: GEORGIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-25 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3473155
• 关键词: blood vessel occlusion; capillary bed; cell adhesion; cell age; cell cell interaction; density gradient ultracentrifugation; endotoxins; erythrocytes; fibrin; fluorescence microscopy; histamine; human subject; human tissue; image processing; interleukin 1; microcirculation; radiotracer; sickle cell anemia; sickle cell crisis; thrombin; tumor necrosis factor alpha; tumor necrosis factor beta; umbilical cord; vascular endothelium; von Willebrand factor

We propose to test the hypothesis that sickle red cell adhesion to endothelial cells initiates or contributes to the localized vaso- occlusive crises characteristic of sickle cell disease. Specifically, we suggest that adhesion varies between endothelial cells from different vascular beds, that adhesion will increase during crisis periods, and that endothelial cell agonists will increase adhesion. We have previously reported that high molecular weight von Willebrand factor (vWF) multimers increase sickle red cell adhesion to umbilical vein endothelial cells. We suggest that endothelial cell stimulation occurs periodically due to chemical or mechanical stresses and leads to localized release of high molecular weight vWF multimers. Preliminary data suggest that adhesion is increased when endothelial cells are stimulated with endotoxin or thrombin. We hypothesize that these multimers bind to sickle erythrocytes and endothelial cells in venules in vivo, leading to vascular obstruction. Recent data indicates that sickle red cells suspended in autologous plasma are more adhesive to microvascular endothelial cells than to umbilical vein endothelial cells. This suggests that the mechanism or red cell adhesion is dependent upon the location of the endothelium. Based on these results we propose that sickle red cell adhesion in vivo is related to complex changes in the erythrocyte surface, the endothelium, and the intravascular milieu. The following parameters are regarded as important determinants of sickle erythrocyte adherence: (i) endothelial cell origin (large or small vessel); (ii) patient clinical condition (crisis or steady-state); (iii) red cell age; (iv) local wall shear stress; (v) the time of exposure of endothelial cells to agonists; and (vi) the duration of contact between sickle erythrocytes, stimulated endothelial cells, and secreted vWF multimers. The influence of these parameters on sickle red cell adhesion to endothelial cells will be investigated in parallel-plate flow chamber adhesion assays. Epi-fluorescence videomicroscopy and digital image processing will be employed to quantify sickle red cell adhesion to stimulated and unstimulated endothelial cells under physiological flow conditions. Development of a red cell recirculation system is proposed to allow red cells, agonists, and endothelial cells continuous contact under flow. Antibody studies will be implemented to determine adhesive receptors on endothelial cells and red cells. Characterization of alterations in the endothelium, plasma, and erythrocytes responsible for increased adhesion in vitro will identify factors not related to hemoglobin S polymerization and red cell sickling which could contribute to or participate in vaso-occlusion in vivo.

我们建议检验镰状红细胞粘附于 内皮细胞启动或促成局部血管， 以镰状细胞病为特征的闭塞性危象。我们特别 表明不同来源内皮细胞之间的粘附性不同， 血管床，在危机期间粘连会增加，以及 内皮细胞激动剂会增加粘附。 我们以前曾报道，高分子量的冯维勒布兰德， 因子（vWF）多聚体增加镰状红细胞粘附到脐 静脉内皮细胞。 我们认为内皮细胞刺激 由于化学或机械应力而周期性地发生， 高分子量vWF多聚体的局部释放。 初步 数据表明，当内皮细胞 细胞 用内毒素或凝血酶刺激。 我们假设这些 多聚体与小静脉中的镰状红细胞和内皮细胞结合 在体内，导致血管阻塞。最近的数据表明 悬浮在自体血浆中的镰状红细胞更粘附于 微血管内皮细胞比脐静脉内皮细胞 细胞 这表明红细胞粘附的机制是 这取决于内皮的位置。 基于这些结果 我们认为镰状红细胞在体内的粘附与复杂的 红细胞表面、内皮细胞和 血管内环境。 以下参数被认为是重要的决定因素， 镰状红细胞粘附：（i）内皮细胞来源（大或小 （ii）患者临床状况（危象或稳态）;（iii） 红细胞年龄;（iv）局部壁切应力;（v）暴露时间 内皮细胞与激动剂的接触时间;和（vi）内皮细胞与激动剂之间的接触时间 镰状红细胞、刺激的内皮细胞和分泌的vWF 多聚体 这些参数对镰状红细胞粘附的影响 将在平行板流动室中研究对内皮细胞的作用 粘附测定。 落射荧光视频显微镜和数字图像 将采用处理来量化镰状红细胞粘附， 在生理流动下的刺激的和未刺激的内皮细胞 条件 红细胞再循环系统的发展提出 使红细胞、激动剂和内皮细胞连续接触 下流。 抗体 将进行研究以确定粘合剂 内皮细胞和红细胞上的受体。 内皮细胞、血浆和血浆中的变化的表征 在体外，负责增加粘附的红细胞将鉴定 与血红蛋白S聚合和红细胞镰状化无关的因素 其可促成或参与体内血管闭塞。