RELATIONSHIP BETWEEN VASCULAR ENDOTHELIAL CELL INJURIES AND RED CELL FRAGMENTATION SYNDROME

红细胞碎裂综合征(RCFS)包括血栓性血小板减少性紫癜(TTP)和药物性溶血性尿毒症综合征(HUS)，病死率较高。血栓调节蛋白(TM)等血管内皮细胞标志物在TTP和HUS患者中显著升高，在药物性HUS患者中略有升高，血浆细胞因子水平显著升高，且与临床病程密切相关。RCFS患者处于高凝、低纤溶状态，多数TTP患者von Willebrand因子高分子量多聚体减少，血小板活化。RCFs患者血浆组织因子途径抑制物(TFPI)水平显著降低，经TTP患者血浆培养的人脐静脉内皮细胞MTT值显著降低，BrDu法检测DNA合成增加，趋化性降低，组织因子(Tf)活性升高，提示多种因素对血管内皮细胞有激活或损伤作用。在丝裂霉素C或其衍生物培养的细胞中，四甲基偶氮唑盐比色法的吸光度、转铁蛋白活性和趋化性均降低。药物性HUS对血管内皮细胞的损伤机制可能与TTP不同。不同的激活或损伤可能影响RCFS的发生。

Red cell fragmentation syndrome (RCFS) including thrombotic thrombocytopenic purpura (TTP) and drug induced hemolytic uremic syndrome (HUS) have a high mortality. Vascular endothelial cell markers as thrombomodulin (TM) were significantly increased in patients with TTP and those with HUS,and these markers were slightly increased in patients with drug induced HUS.Plasma cytokyne levels were significantly increased and these were well correlated with clinical course. The patients with RCFS were hypercoagulableand hypofibrinolytic state, and decreased high molecular weight multimer of von Willebrand factor and activation of platelets were observed in most of TTP patients. Plasma level of tissue factor pathway inhibitor (TFPI) were significantly decreased in patients with RCFS.In human umbilical venous endothelial cell cultured with plasma of TTP patients, the absorbance of MTT assay was significantly decreased, and DNA synthesis was increased by BrDu assay, and chemotaxis was decreased, and tissue factor (TF) activity was increased, suggesting that there were several factors activating or injuring vascular endothelial cells. In thses cells cultured with mitomicin C or its derivative, the absorbance of MTT assay, TF activity, and chemotaxis reduced. The mechanism of vascular endothelial cell injuries in drug induced HUS might be different from those in TTP.Various activation or injuries might effect the onset of RCFS.