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出凝血功能改变在子痫前期发病机制中的作用
Role of Haemostasis and Thrombosis in the Pathogenesis of Preeclampsia
【作者】 熊钰；
【作者基本信息】 复旦大学 ， 妇产科学， 2008， 博士
【摘要】 子痫前期为孕产妇常见的严重并发症,是引起母亲和胎儿死亡的主要原因之一。尽管至今对于子痫前期发病的确切病因和机制仍不明确,但已经证实其病理生理变化的核心是内皮细胞功能紊乱与障碍。由于内皮细胞功能紊乱,其合成和分泌的一系列凝血和抗凝血因子、纤溶和抗纤溶因子发生改变,导致凝血与纤溶平衡失调,可能在子痫前期发病过程中起关键作用。但目前的研究尚未阐明内皮细胞功能紊乱导致子痫前期孕妇出凝血功能改变的具体作用机制及出凝血功能改变与子痫前期发病的因果关系。本研究中,首先研究了正常妊娠晚期孕妇和胎儿出凝血功能的改变。在此基础上,研究了子痫前期孕妇和胎儿出凝血功能的改变,分析孕妇出凝血功能的改变与子痫前期病情严重程度及母儿并发症的关系。并进一步使用低分子肝素治疗早发型子痫前期孕妇,观察其出凝血功能的改变。旨在研究子痫前期时机体出凝血功能发生改变的机制,寻找敏感、有效的出凝血指标监测子痫前期的病情变化,探讨出凝血功能的改变与子痫前期发病的关系。TFPI-2是出凝血系统中特殊的成员,与细胞基质重塑、血管生成、肿瘤细胞转移及细胞凋亡等功能有关。但目前对于TFPI-2在妊娠期的功能了解甚少。因此,本研究拟采用时间分辨荧光免疫分析法(TRFIA)和免疫组化的方法,观察非妊娠妇女、早中晚期正常妊娠妇女和子痫前期患者血浆、胎盘TFPI-2的改变,探讨TFPI-2在正常妊娠生理和子痫前期发病机制中的作用。第一部分正常妊娠孕妇和胎儿出凝血功能的改变第一节正常妊娠孕妇出凝血功能的改变目的:探讨正常妊娠晚期及产后孕妇出凝血功能包括血管内皮细胞功能、凝血功能、抗凝血功能和纤溶功能的改变特点。材料和方法:收集正常妊娠妇女(n=40)分娩前后和非妊娠妇女(n=20)的血浆,采用ELISA法检测血浆von Willebrand因子(vWF)、组织因子(TF)、组织因子途径抑制物(TFPI)、纤维蛋白肽A(FPA)和D-二聚体(D-Dimer)的含量,并比较两组的检测结果。结果:与非妊娠妇女相比,正常妊娠妇女血浆vWF、TFPI和D-二聚体的含量在分娩时、产后1天和5天均显著增高(P＜0.01),TF的含量在分娩时显著增高(P＜0.05),FPA的含量在分娩时、产后1天和5天相比较均无显著性差异(P＞0.05)。与分娩时相比,产后血浆vWF和TF的含量呈下降趋势,TFPI和D-二聚体的含量呈上升趋势,FPA的含量无明显变化(P＞0.05)。结论:正常妊娠晚期,孕妇处于高凝状态,同时抗凝功能和纤溶活性也增强,保持着高水平的动态平衡。产后高凝状态逐步趋于缓解,纤溶系统功能活跃。第二节正常妊娠胎儿出凝血功能的改变目的:探讨正常妊娠胎儿出凝血功能包括血管内皮细胞功能、血小板活化功能、凝血功能、抗凝血功能和纤溶功能的改变特点。材料和方法:收集上述正常妊娠妇女(n=40)胎盘脐静脉血浆,采用ELISA法检测血浆vWF、TF、TFPI、P-选择素(sP-selectin)、FPA、抗凝血酶Ⅲ(AT-Ⅲ)和D-二聚体的含量,并与其母体分娩时的血浆出凝血指标检测结果相比较。结果:脐血血浆TF和P-选择素的含量(68.97±5.95ng/L和91.78±7.84μg/L)显著高于母血(56.17±5.72ng/L和77.43±6.57μg/L)(P＜0.05),vWF、TFPI和AT-Ⅲ的含量(分别为:871.44±118.97U/L,41.72±3.78μg/L和265.13±37.31mg/L)显著低于母血(分别为:2435.99±155.09U/L,93.39±4.85μg/L和710.09±183.94mg/L)(P＜0.05)。脐血血浆FPA和D-二聚体的含量低于母血,但比较差异无显著性意义(P＞0.05)。结论:与母体的高凝状态相比,正常足月妊娠胎儿处于更明显的高凝状态。第二部分子痫前期孕妇和胎儿出凝血功能的改变第一节子痫前期孕妇出凝血功能的改变目的:探讨子痫前期孕妇出凝血功能包括血管内皮细胞功能、血小板活化功能、凝血功能、抗凝血功能和纤溶功能的改变特点。方法:收集子痫前期孕妇(n=46)分娩前后的血浆,采用ELISA法检测血浆vWF、TF、TFPI、P-选择素、FPA、AT-Ⅲ和D-二聚体的含量,并与上述正常孕妇分娩前后血浆出凝血指标的检测结果相比较。结果:与正常孕妇相比,子痫前期孕妇血浆TF的含量在分娩时、产后1天和5天均显著升高(P＜0.05);vWF和P-选择素的含量有升高趋势,其中在产后1天的差异有显著性(P＜0.05);TFPI和D-二聚体的含量有下降趋势(P＞0.05);AT-Ⅲ的含量在分娩时有下降趋势,产后有升高趋势(P＞0.05);FPA的含量无显著性变化(P＞0.05)。与分娩时相比,产后血浆TF、vWF和P-选择素的含量呈下降趋势,TFPI、AT-Ⅲ和D-二聚体的含量呈上升趋势,FPA的含量无明显变化(P＞0.05)。结论:子痫前期时孕妇血管内皮细胞受到严重损伤,伴随着血小板活性和凝血功能显著增强,而抗凝功能和纤溶功能减弱,导致凝血/纤溶平衡失调,机体处于病理性高凝状态并具血栓形成倾向是子痫前期重要的病理生理改变。第二节子痫前期胎儿出凝血功能的改变目的:探索子痫前期胎儿出凝血功能包括血管内皮细胞功能、血小板活化功能、凝血功能、抗凝血功能和纤溶功能的改变特点及子痫前期对胎儿出凝血功能的影响。方法:收集上述子痫前期孕妇(n=46)胎盘脐静脉血浆,采用ELISA法检测血浆vWF、TF、TFPI、P-选择素、FPA、AT-Ⅲ和D-二聚体的含量,并与其母体分娩时及正常妊娠胎儿的血浆出凝血指标检测结果相比较。结果:与母体相比,子痫前期胎儿血浆TF的含量显著上升(P＜0.05),vWF、TFPI和AT-Ⅲ的含量显著降低(P＜0.05),P-选择素和D-二聚体的含量有下降趋势但差异无统计学意义(P＞0.05),FPA的含量无显著性变化(P＞0.05)。与正常妊娠胎儿相比,子痫前期胎儿血浆TF的含量显著升高(P＜0.05),vWF的含量升高而P-选择素的含量降低但差异均无统计学意义(P＞0.05),其它出凝血指标的含量无显著性变化(P＞0.05)。结论:子痫前期胎儿处于较其母体和正常妊娠胎儿更明显的高凝状态和血栓形成倾向,可能与发生FGR、PAS、流产等并发症的风险增高有关。第三部分出凝血功能改变与子痫前期病情严重程度及母儿并发症的关系目的:探讨孕妇出凝血功能的改变与子痫前期病情严重程度和母儿并发症之间的关系,寻找敏感、有效的出凝血指标监测子痫前期病情的变化,判断疾病的严重程度并预测其并发症的发生。方法:在上述的研究基础上,分析子痫前期病情的严重程度与孕妇和胎儿出凝血功能改变的关系。子痫前期病情观察指标包括血压、蛋白尿、肝肾功能、血常规、分娩孕周、出生体重、Apgar评分和母儿并发症等。统计方法采用相关性分析和t检验。结果:1.收缩压(SBP)和舒张压(DBP)与TF之间有显著的相关性(r=0.218和r=0.234,P＜0.05);尿蛋白(PU)与TF和P-选择素之间有显著的相关性(r=0.225和r=0.229,P＜0.05);其它临床指标与出凝血指标之间均无显著相关性。2.以SBP=160mmHg为界,将孕妇分为两组,比较两组间出凝血功能的差别。高血压组孕妇血浆TF的含量在分娩时、产后1天和5天均显著高于低血压组(P＜0.05);vWF、FPA、P-选择素和TFPI的含量有增高趋势,AT-Ⅲ的含量有下降趋势,其中vWF在产后1天的差异有显著性,FPA在产后5天的差异有显著性(P＜0.05)。孕妇血浆D-二聚体的含量和常规凝血功能检查在两组间均无显著性差异(P＞0.05)。3.以尿蛋白=++为界,将孕妇分为两组,比较两组间出凝血功能的差别。高尿蛋白组孕妇血浆P-选择素的含量在分娩时、产后1天和5天均显著高于低尿蛋白组(P＜0.05);TF和vWF的含量有增高趋势,其中TF在分娩时和产后5天的差异有统计学意义(P＜0.05)。孕妇血浆其它出凝血指标的含量和常规凝血功能检查在两组间均无显著性差异(P＞0.05)。4.以有无母体并发症,将孕妇分为两组,比较两组间出凝血功能的差别。有母体并发症组母血血浆TF和vWF的含量(74.33±22.32ng/L和2629.21±226.40U/L)明显高于无母体并发症组(49.17±3.97ng/L和2106.79±159.64U/L)(P=0.06和P=0.07),脐血血浆TF、TFPI和vWF的含量均显著高于无母体并发症组(P＜0.05)。母血和脐血血浆其它出凝血指标的含量在两组间均无显著性差异(P＞0.05)。5.以有无新生儿并发症,将孕妇分为两组,比较两组间出凝血功能的差别。有新生儿并发症组母血和脐血血浆TF的含量(86.21±19.65ng/L和161.63±74.39ng/L)均显著高于无新生儿并发症组(51.62±4.50ng/L和72.38±5.17ng/L)(P＜0.05)。母血和脐血血浆其它出凝血指标的含量在两组间均无显著性差异(P＞0.05)。结论:孕妇的出凝血功能发生改变使之处于高凝状态的程度,与子痫前期病情严重程度及母儿并发症的发生率呈正相关,其中TF的改变最敏感。孕妇血浆TF含量可作为监测子痫前期病情严重程度的有效指标。第四部分早发型子痫前期保守治疗的疗效观察目的:上述研究提示孕妇的高凝状态与子痫前期的病情严重程度有关。本研究旨在应用低分子肝素(LMWH)纠正早发型子痫前期患者的高凝状态,改善母胎预后,探讨LMWH治疗早发型子痫前期的可行性。方法:43例早发型子痫前期孕妇分成两组,16例使用LMWH治疗(研究组),27例使用常规治疗(病例对照组)。LMWH(速碧林)5000IU,皮下注射,每天一次,共一周。比较两组之间血浆vWF、TF、P-选择素和FPA的含量。结果:与病例对照组比较,研究组孕妇的血压(包括收缩压和舒张压)显著降低,继续妊娠时间显著延长(P＜0.05)。研究组孕妇血浆TF的含量在分娩时、产后1天和5天均显著低于病例对照组(P＜0.05);vWF、FPA和P-选择素的含量有下降趋势,在分娩时差异均有统计学意义(P＜0.05)。结论:LMWH治疗早发型子痫前期患者,可以显著改善孕妇的高凝状态,缓解临床症状,并降低母儿并发症的发生率。说明出凝血功能发生改变使机体处于病理性高凝状态并具血栓形成倾向可能是导致子痫前期发病及病情加重的重要因素,其中血管内皮细胞受损导致TF大量释放,启动外源性凝血途径起关键作用。第五部分TFPI-2在子痫前期发病机制中的作用目的:TFPI-2是出凝血系统中特殊的成员,与细胞基质重塑、血管生成、调控肿瘤细胞转移及调节细胞凋亡等功能有关。本研究旨在比较正常妊娠和子痫前期孕妇血浆和胎盘TFPI-2的表达差异,探讨TFPI-2在正常妊娠生理和子痫前期发病机制中的作用。方法:收集非妊娠妇女(n=20)、不同孕龄的正常孕妇(n=518)、正常孕妇(n=40)和子痫前期孕妇(n=46)分娩前后的血浆及早、中、晚期正常孕妇和轻度、重度子痫前期孕妇(n=3)的胎盘组织。采用时间分辨荧光免疫分析法(TRFIA)检测血浆TFPI-2的含量,免疫组化检测胎盘TFPI-2的含量。分析血浆TFPI-2在孕前、孕期及产后的变化特点并比较正常妊娠和子痫前期孕妇血浆和胎盘TFPI-2的表达差异。结果:1.血浆TFPI-2的含量在非孕时为16.04±3.58μg/L,一旦妊娠迅速上升,孕13周时达到非孕时的9.3倍(149.31±17.15μg/L),孕39-40周时达到高峰是非孕时的17.6倍(282.58±17.15μg/L),其后呈下降趋势,孕42周时降至255.27±49.88μg/L,产后迅速降至非孕水平。2.子痫前期孕妇血浆TFPI-2的含量在分娩时(193.85±18.80μg/L)显著低于正常孕妇(263.37±8.73μg/L)(P＜0.05),但仍显著高于非妊娠妇女(16.04±3.58μg/L)(P＜0.01),产后1天(16.39±5.40μg/L)恢复至非孕水平。3.TFPI-2仅在胎盘合体滋养细胞的胞浆中检测到,而在其它任何细胞如细胞滋养细胞、蜕膜细胞、间质细胞或绒毛血管内皮细胞均无TFPI-2的表达。TFPI-2在胎盘中的表达水平随妊娠的进展逐渐升高。子痫前期胎盘TFPI-2的表达水平低于正常妊娠且与病情的严重程度呈正相关。结论:TFPI-2是来自胎盘合体滋养细胞分泌的蛋白。TFPI-2在血浆和胎盘含量的高低与胎盘功能呈正相关,TFPI-2可能是维持妊娠生理的重要因子。TFPI-2可能与子痫前期的发病有关,其作用机制可能是通过直接或间接途径影响滋养细胞的侵袭、凋亡、分化和增殖等功能。
【Abstract】 Preeclampsia is a frequent complication of pregnancies and is one of the leading causes of maternal and neonatal mortality and morbidity worldwide.Although the exact pathogenesis of preeclampsia is not fully understood,it is confirmed that the core of pathophysiological mechanisms is the dysfunction of maternal vascular endothelium. Alterations in the haemostatic system resulting in the pathological hypercoagulability and thrombophilias may contribute to the clinical spectrum of preeclampsia.However,the role of the endothelium dysfunction in hypercoagulability and thrombophilias and the importance of the various critical molecules of haemostatic system in the development of proteinuria and hypertension during preeclampsia remain to be elucidated.In this research,we first studied the alternations of haemostasis and thrombosis in normal pregnancy.Secondly,we investigate the alternations of haemostasis and thrombosis in preeclampsia and analyzed the relationship between these alternations and severity. Finally,we applied low molecular weight heparin(LMWH) to treat women with early onset preeclampsia and observed the changes of haemoststic system.We proposed to explore the mechanisms of the alternations of haemostasis and thrombosis in preeclampsia,to search more sensitive and effective haemostatic parameters for the monitoring of condition of preeclampsia,further we will investigate the role of haemostasis and thrombosis in the pathogenesis of preeclampsia.TFPI-2 is a special anticoagulant factor which has several functions including remolding of cell matrix,angiogenesis,regulating of tumor invasion and cell apoptosis.The physiological functions of TFPI-2 in pregnancy are poorly understood.In order to invetigate the role of TFPI-2 in normal pregnancy and in the pathogenesis of preeclampsia,we used time-resolved fluoroimmunoassay(TRFIA) and immunohistochemistry to evaluate maternal serum concentrations and placental,expression of TFPI-2 in nonpregnant women,normal pregnant women at different trimesters and preeclamptic women. Section 1 Maternal and Fetal alternations of haemostasis and thrombosis in normal pregnancySection 1.1 Maternal alternations of haemostasis and thrombosis in normal pregnancyObjective:To explore the maternal changes of haemostasis and thrombosis, including vascular endothelial functions,coagulant activation, anticoagulant activation and fibrinolytic activation,in normal pregnancy before and after delivery.Methods:Maternal serum concentrations of von willebrand factor(vWF), tissue factor(TF),tissue factor pathway inhibitor(TFPI), fibrinopeptide A(FPA) and D-Dimer were measured by ELISA in forty normal pregnant women and twenty healthy women without pregnancy.Results:Compared with serum of nonpregnant women,serum levels of vWF, TFPI and D- Dimer in pregnant women increased significantly before and after delivery(P＜0.01),and serum levels of TF increased significantly at delivery(P＜0.05).Serum levels of FPA were similar between pregnant and nonpregnant women(P＞0.05).A lower trend of maternal serum concentrations of vWF and TF were observed after delivery,companied with a higher trend of maternal serum concentrations of TFPI and D- Dimer(P＞0.05).Conclusion:During normal pregnancy the activation of coagulation is counterbalanced by the activation of fibrinolysis and anticoagulation, which maintains the haemostatic balance.The decreased coagulation and increased anticoagulation and fibrinolysis resulted in the fibrinolytic accentuation after delivery.Section 1.2 Fetal alternations of haemostasis and thrombosis in normal pregnancyObjective:To explore the fetal changes of haemostasis and thrombosis in normal pregnancy,including vascular endothelial functions,platelet activation,coagulant activation,anticoagulant activation and fibrinolytic activation.Methods:Fetal serum concentrations of vWF,TF,TFPI,soluble P-selectin (sP-selectin),antithrombaseⅢ(AT-Ⅲ),FPA and D-Dimer were measured by ELISA in forty normal pregnant women.Results:Fetal serum levels of TF and sP-selectin(68.97±5.95ng/L and 91.78±7.84μg/L) were significantly higher than maternal serum (56.17±5.72ng/L and 77.43±6.57μg/L)(P＜0.05,respectively),while fetal serum levels of vWF,TFPI and AT-Ⅲ(871.44±118.97U/L, 41.72±3.78μg/L and 265.13±37.31mg/L) were significantly lower than maternal serum(2435.99±155.09U/L,93.39±4.85μg/L and 710.09±183.94mg/L)(P＜0.05,respectively).Fetal serum levels of FPA and D-Dimer were higher than maternal serum(P＞0.05).Conclusion:The hypercoagulable state in fetus is even more prominent with increased coagulation and decreased anticoagulation and fibrinolysis as compared with mother.Section 2 Maternal and Fetal alternations of haemostasis and thrombosis in preeclampsiaSection 2.1 Maternal alternations of haemostasis and thrombosis in preeclampsiaObjective:To investigate the maternal changes of haemostasis and thrombosis in preeclampsia,including vascular endothelial functions, platelet activation,coagulant activation,anticoagulant activation and fibrinolytic activation.Methods:Maternal serum concentrations of vWF,TF,TFPI,sP-selectin, AT-Ⅲ,FPA and D-Dimer were measured by ELISA in forty-six women with preeclampsia and forty normal pregnant women before and after delivery.Results:Compared with maternal serum in normal pregnancy,higher concentrations of maternal serum TF,vWF and sP-selectin as well as lower concentrations of maternal serum TFPI and D-Dimer in preeclampsia were observed before and after delivery.Maternal serum levels of AT-Ⅲdecreased at delivery and increased after delivery.A lower trend of maternal serum concentrations of vWF,TF and sP-selectin were found after delivery,companied with a higher trend of maternal serum concentrations of TFPI,AT-Ⅲand D- Dimer.Maternal serum concentrations of FPA were similar between two groups before and after delivery.Conclusions:Pathological hypercoagulability and thrombophilias resulted from changes in the haemostatic system which included impaired endothelial functions,increased coagulation and platelet activation and decreased anticoagulation and fibrinolysis are the important pathophysiological alternations in preeclampsia.Section 2.2 Fetal alternations of haemostasis and thrombosis in preeclampsiaObjective:To investigate the fetal changes of haemostasis and thrombosis in preeclampsia,including vascular endothelial functions,platelet activation,coagulant activation,anticoagulant activation and fibrinolytic activation.Methods:Fetal serum concentrations of vWF,TF,TFPI,sP-selectin,AT-Ⅲ, FPA and D-Dimer were measured by ELISA in forty-six women with preeclampsia and forty normal pregnant women.Results:Compared with maternal serum,fetal serum concentrations of vWF, TFPI and AT-Ⅲwere decreased significantly in preeclampsia,while TF concentrations were increased significantly.Fetal serum concentrations of sP-selectin and D-Dimer were lower than maternal serum although the difference had no significance.Serum levels of FPA were similar between mothers and fetus.Compared with fetal serum in normal pregnancy,fetal serum concentrations of TF were markedly increased in preeclampsia, accompanied with a higher level of vWF and a lower level of sP-selectin but without statistical significance.Fatal serum levels of other haemostatic parameters were similar between normal pregnancy and preeclampsia.Conclusion:The hypercoagulable state and thrombophilias of fetus in preeclampsia is even more prominent than its mothers and fetus in normal pregnancy which resulted in the higher incidence of complications such as FGR,PAS and abortion. Section 3 Relationship between alternations of haemostasis and thrombosis and severity of preeclampsiaObjective:To explore the relationship between alternations of haemostasis and thrombosis and severity of preeclampsia and search sensitive and effective haemostatic parameters to monitor the condition of preeclampsia.Methods:Based on above research,we used bivariate correlation and t test to analyze the relationship between maternal and fetal changes of haemostasis and thrombosis and severity of preeclampsia which were judged by the clinical parameters including blood pressure,proteinuria,liver and renal functions,blood routine examination,birth weeks,birth weight, Apgar scores and maternal and fetal complications.Results:1.There were significant positive relationships between SBP, DBP and TF(r=0.218 and r=0.234;p＜0.05,respectively).And also, significant positive relationships between proteinuria and TF, sP-selectinwere observed(r=0.225 and r=0.229;p＜0.05,respectively). No marked relationships were observed between other clinical parameters and the hemostatic parameters.2.According to SBP as 160mmHg,we further divided these pregnant women into two groups.Maternal Serum concentrations of TF were significantly increased in hypertensive group than in normotensive group before and after delivery.On the other hand, a higher trend of vWF,FPA,sP-selectin,TFPI and a lower trend of AT-Ⅲwere observed in hypertensive groups before and after delivery, especially the differences of vWF at delivery and FPA on day 5 after postpartum had significance.Maternal serum levels of D-Dimer and routine haemostatic examinations were similar between two groups.3.Similarly, all participants were divided into abnormal group(proteinuria≥++) and normal group(proteinuria＜++).Maternal serum concentrations of sP-selectin were significantly increased before and after delivery,well as maternal serum concentrations of TF were increased significantly at delivery and on day 5 after postpartum in abnormal group than in normal group.In addition,maternal serum levels of other parameters and routine haemostatic examinations were similar between two groups.4.Acording to maternal complications,all pregnant women were divided into two groups. Fatal serum levels of TF,TFPI and vWF were increased significantly in group with maternal complications compared with group without maternal complications.Maternal serum levels of TF and vWF were highter in group with maternal complications than in group without maternal complications (74.33±22.32ng/L and 2629.21±226.40U/L vs 49.17±3.97ng/L and 2106.79±159.64U/L;P=0.06,P=0.07,respectively).Maternal and fetal serum levels of other parameters were similar between two groups.5. Acording to fetal complications,all pregnant women were divided into two groups.Maternal and fetal serum concentrations of TF increased significantly in group with fetal complications compared with group without fetal complications(86.21±19.65ng/L and 161.63±74.39ng/L vs 51.62±4.50ng/L and 72.38±5.17ng/L;P＜0.05,respectively).Maternal and fetal serum levels of other parameters were similar between two groups.Conclusion:The degree of bypercoagulable state is positively related to the severity of preeclampsia,especially the serum levels of TF is the most sensitive changes which can be used to monitor the severity of preeclampsia.Section 4 Expectant treatment of early onset preeclampsiaObjective:It is found that the degree of hypercoagulable state is positively related to the severity of preeclampsia through above studies. Therefore we investigated the feasibility of expectant treatment which used LMWH to correct the hypercogulable state of women with early onset preeclampsia.Methods:Maternal serum concentrations of vWF,TF,TFPI and FPA were measured by ELISA in sixteen women with early onset preeclampsia who received 5000IU/d LMWH about seven days and twenty-seven women with early onset preeclampsia who received routine treatmen.Results:SBP and DBP were decreased significantly and gestational weeks were prolonged significantly in study group compared with the control group.Maternal serum levels of IF decreased significantly in study group than in the control group before and after delivery,well as maternal serum levels of vWF,FPA and sP-selectin decreased significantly in study group at delivery.Conclusion:Our study revealed that LMWH can effectively improve the hypercoagulable state of women with early onset preeclampsia,smoothing the clinical symptoms and decrease the incidence of maternal and fetal complications.The pathological changes of haemostasis and thrombosis may play an important role in the pathogenesis of preeclampsia and result to aggravate the illness.The abundant release of TF resulted from impairment of vascular endothelial cells,which triggered the extrinsic pathway of coagulation,may play a key role in the pathogenesis of preeclampsia.Section 5 Role of TFPI-2 in the pathogenesis of preeclampsiaObjective:TFPI-2 is a special anticoagulant factor which had several functions including remolding of cell matrix,angiogenesis,regulating of tumor invasion and cell apoptosis.In order to explore the physiological functions of TFPI-2 in normal pregnancy and the role in the pathogenesis of preeclampsia,we evaluated maternal serum concentration and placental expression of TFPI-2 in normal pregnancy and preeclampsia.Methods:Maternal serum and placental concentrations of TFPI-2 were measured by time resolved fluoroimmunoassay(TRFIA) and Immunohistochemistry in twenty women without pregnancy,five hundred and eighteen normal pregnant women at different trimesters,forty women in normal pregnancy and forty-six women in preeclampsia before and after delivery.Results:1.Maternal serum levels of TFPI-2 in normal pregnant women at 13 weeks of gestation increased 9.3 times as compared with healthy women without pregnancy(149.3±17.1 vs 16.0±3.6ng/ml).This was followed by a gradual increase towards term,reached a maximum mean value of 282.6±17.1ng/ml at 39 weeks of gestation and then gradual decreased to 259.3±49.8ng/ml at 42 weeks of gestation.2.Maternal serum concentrations of TFPI-2 were significantly higher in normal pregnancy than inpreeclampsia(263.4±8.7 vs 193.8±18.8ng/ml),but there were no significant differences in this value which dramatically decreased to non-pregnant levels after delivery between two groups.3.TFPI-2 was detected in the cytoplasm of syncytiotrophoblasts,but not in any other type of cell such as cytotrophoblasts,decidual cells,stromal cells,or chorionic vascular endothelial cells.Placental expression of TFPI-2 was low during the first trimester,increased gradually in the second trimester and reached a maximum level in the third trimester.Placental expression of TFPI-2 decreased significantly in preeclampsia compared to normal pregnancy,well as it decreased significantly in severe preeclampsia than in mild preeclampsia.Conclusion:TFPI-2 is secreted from the cytotrophoblasts in placenta and may play an important role in maintaining the normal pregnancy.TFPI-2 may also play a role in the pathogenesis of preeclampsia through affecting invasion,apoptosis,differentiation and proliferation of trophoblasts.