PLATELET/ENDOTHELIAL CELL INTERACTIONS

急性冠状动脉血栓形成机制的最新研究进展 综合征和动脉血管重建术(例如，经皮穿刺术 腔内冠状动脉成形术(PTCA)表明组织的主要作用 因子(TF)在动脉壁血栓和纤维蛋白生成中的作用。 这种转铁蛋白的来源包括软脂核、巨噬细胞，可能还有 平滑肌细胞(SMC)。然而，最近的体外数据表明， 1例间质小泡来源于内皮功能障碍 细胞(ECs)可能是局部扰动、缓慢流动的额外来源 分支点和分叉点的区域特征。这样的ECS可以 也直接激活SMC产生转铁蛋白，因为在体内至少有一些 动脉粥样硬化病变的SMC表达转铁蛋白。因此，我们将测试 内皮细胞控制动脉粥样硬化中转铁蛋白积聚的假说 斑块。这可能是正确的两种方式是EC将Tf释放到 内皮下层，内皮细胞和内皮细胞激活以表达转铁蛋白。 具体目的1是通过以下方式表征Tf的功能表达 猪主动脉内皮细胞在流室中预适应到低切变水平 应力，无或有低氧，无或有振荡剪切 压力，持续时间长达24小时。具体目标2是扩大我们的 猪主动脉单层共培养系统的研究结果 ECS覆盖在SMC之上。具体目标3是对转移因子进行平行研究 用猪主动脉节段表达，也在流动装置中表达。这些 AIMS将包括Xa因子的产生和结合，Tf的评估 抗原和基因表达，以及在受控球囊损伤后 体外共培养和主动脉节段的血小板定量 荧光视频显微镜和/或111-铟的黏附/聚集 (托洛酮)标记的血小板和125-碘标记的纤维蛋白原。一个 更清楚地了解切应力条件下的内皮细胞可能被证明是重要的 在Tf或因子Xa的特异性抑制剂的开发中，以及在 经皮冠状动脉腔内成形术(PTCA)等手术所致病变的EC再植。

Recent research into the mechanisms of thrombosis during acute coronary syndromes and arterial revascularization procedures (e.g., percutaneous transluminal coronary angioplasty; PTCA) indicates a major role for tissue factor (TF) in the generation of arterial mural thrombi and fibrin. Sources of this TF include soft lipid core, macrophages, and possibly smooth muscle cells (SMCs). Recent in vitro data, however, make a strong case that interstitial vesicles derived from dysfunctional endothelial cells (ECs) may be an additional source in the local disturbed, slow flow regions characteristic of branch points and bifurcations. Such ECs may also directly activate SMCs to produce TF, since in vivo at least some SMCs of atherosclerotic lesions express TF. We will therefore test the hypothesis that ECs control the accumulation of TF in atherosclerotic plaques. Two ways in which this may be true are EC release of TF into subendothelium, and EC activation of underlying SMCs to express TF. Specific Aim 1 is to characterize the functional expression of TF by porcine aortic ECs preconditioned in a flow chamber to low levels of shear stress, without or with hypoxia, and without or with oscillatory shear stress, for periods up to 24 hours. Specific Aim 2 is to extend our findings to a coculture system comprised of a monolayer of porcine aortic ECs overlying SMCs. Specific Aim 3 is to perform parallel studies of TF expression with segments of porcine aorta, also in a flow device. These aims will incorporate factor Xa generation and binding, assessment of TF antigen and gene expression, and, following controlled balloon injury to cocultures and aortic segments in vitro, quantification of platelet adhesion/aggregation by epifluorescence videomicroscopy and/or 111-indium (tropolone)-labelled platelets and 125-iodine-labelled fibrinogen. A clearer understanding of shear stress-conditioned ECs may prove important in the development of specific inhibitors of TF or factor Xa, and in the EC repopulation of lesions induced by such procedures as PTCA.