代谢综合征患者纤溶活性与胰岛素抵抗的关系

目的:探讨代谢综合征患者血浆纤溶活性及与胰岛素抵抗的关系。方法:选择单纯代谢综合征患者36例,代谢综合征合并冠心病患者44例和健康人群对照20例。观察一般情况,并测定血浆纤溶酶原激活抑制物-1(PAI-1)和组织型纤溶酶原激活物(t-PA)、纤维蛋白原(Fib)、空腹血糖(FBG)、空腹血胰岛素(Ins)和血脂等指标;计算胰岛素敏感指数(ISI)。结果:代谢综合征患者的ISI较正常对照组明显下降(P<0.05);血浆PAI-1、Fib等明显升高(P<0.05)。代谢综合征合并冠心病组PAI-1与Fib、Ins正相关,与ISI、高密度脂蛋白(HDL)负相关。结论:代谢综合征患者存在明显的胰岛素抵抗和纤溶活性异常,同时纤溶活性异常与胰岛素抵抗相关。     

纤溶酶原激活物抑制因子-1蛋白分子的结构与功能

纤溶酶原激活物抑制因子-1(PAI-1)是组织型纤溶酶原激活物(t-PA)和尿型纤溶酶原激活物(u-PA)的特异性抑制剂。对PAI-1分子的结构与功能的认识,有助于了解PAI-1发挥抑制 作用的机理。本文综述了近年来对PAI-1蛋白分子结构与功能研究的进展,介绍了PAI-1分子中一些区域的作用以及影响PAI-1抑制活性的一些因子。     

辛伐他汀对尼古丁诱导脐静脉 内皮细胞分泌t-PA和PAI-1的影响

目的: 研究不同浓度辛伐他汀对尼古丁诱导人脐静脉内皮细胞(HUVECs)分泌组织纤溶酶原激活物(t-PA)和1型纤溶酶原激活物抑制剂(PAI-1)及其基因表达的影响。方法: 将3-6代体外培养的HUVECs随机分为对照组、尼古丁组及不同浓度辛伐他汀组,辛伐他汀组分别以1、10、100 μmol/L辛伐他汀预处理细胞2 h,再以100 μmol/L尼古丁孵育24 h。酶联免疫吸附双抗体夹心法(ELISA)检测细胞上清液t-PA和PAI-1含量;逆转录聚合酶链反应(RT-PCR)检测细胞t-PA和PAI-1 mRNA的表达。结果: 尼古丁组PAI-1分泌和mRNA表达较对照组显著升高(P<0.05)。不同浓度辛伐他汀组PAI-1分泌和mRNA表达均较尼古丁组显著降低,且PAI-1分泌和mRNA表达的降低呈浓度依赖性(均P<0.05),以100 μmol/L辛伐他汀组最为显著。100 μmol/L辛伐他汀组PAI-1分泌和mRNA表达与对照组比较,无显著差异(P>0.05)。尼古丁组t-PA mRNA表达较对照组显著降低(P<0.05)。10、100 μmol/L辛伐他汀组t-PA mRNA表达较尼古丁组显著升高(P<0.05),各组间t-PA分泌无显著差异(均P>0.05)。结论: 在体外,辛伐他汀可降低尼古丁所致的PAI-1分泌和mRNA的表达,并升高t-PA mRNA的表达,从而逆转尼古丁介导的HUVECs纤溶活性减低。     

PTCA前后t-PA及PAI-I的动态变化及意义

目的观察急性冠脉综合征（ACS）患者冠脉成形术（PTCA）前后血浆组织型纤溶酶原激活物（t-PA）及纤溶酶原激活抑制剂（PAI-I）的动态变化。探讨PTCA对机体纤溶功能的影响。方法采用发光底物法对36例ACS患者在PTCA前及后4、12、24、48、72h时间段测定血浆中t-PA和PAI-I的活性。结果PTCA术后4、12、24、48、72ht-PA活性明显降低，但术后24h开始t-PA活性呈逐渐升高趋势。PTCA术后4、12、48、72hPAI-I活性明显升高，但术后24h开始PAI-I活性呈逐渐下降趋势。结论ACS患者PTCA后存在着明显的纤溶功能低下．纤溶水平的高低与PTCA治疗效果及再梗塞发生有关。提示机体纤溶功能影响PTCA的手术效果。     

尼古丁对血管内皮细胞释放t-PA及PAI-1的影响

目的: 研究尼古丁对人脐静脉内皮细胞(HUVECs)释放组织型纤溶酶原激活物(t-PA)和纤溶酶原激活物抑制物-1(PAI-1)的影响。方法: HUVECs培养后接种于24孔培养板中,随机分为对照组及实验组,分别进行以下实验。(1)以0.1、1、10、100 μmol/L 尼古丁孵育HUVECs,12 h后收集各组上清液;(2)以100 μmol/L尼古丁与HUVECs孵育0、4、6、8、12 及24 h,收集各组上清液。采用ELISA法测定各组t-PA和PAI-1的浓度。结果: HUVECs与不同浓度尼古丁孵育12 h后,100 μmol/L尼古丁组PAI-1蛋白较对照组明显增加(P<0.01);0.1、1及10 μmol/L尼古丁组PAI-1蛋白与对照组比较,均无显著差异(均P>0.05);各浓度组t-PA蛋白与对照组比较,均无显著差异(均P>0.05)。HUVECs 与100 μmol/L的尼古丁分别孵育4 、6 、8 、12 及24 h,各组PAI-1蛋白均较对照组明显升高(P<0.05),且其升高呈时间依赖性;各组t-PA与对照组比较,均无显著差异(均P>0.05)。结论: 尼古丁可抑制HUVECs的纤溶活性,对内皮细胞具有损伤作用。     

妊娠高血压综合征患者vWF、t-PA、PAI-1的检测分析

目的:探讨妊娠高血压综合征(妊高征)患者内皮细胞功能指标的变化及其临床意义。方法:应用ELISA法及发色底物法测定妊高征患者血浆血管性血友病因子(vWF)、织织型纤溶酶原激活物(t-PA)及纤溶酶原激活抑制物-1(PAI-1)活性。结果:妊高征患者vWF、t-PA、PAI-1较正常非孕组明显升高(P<0.05或P<0.01);妊高征各组患者vWF、PAI-1活性比正常晚孕组显著增高(P<0.05或P<0.01),且病情越重增高越明显;t-PA无明显改变。中、重度妊高征组血浆vWF与PAI-1水平呈直线正相关关系(r=0.723,P<0.05;r=0.765,P<0.05)。结论:妊高征患者内皮细胞功能异常,凝血及纤溶抑制功能亢进。测定血浆vWF和PAI-1水平,对于临床诊断妊高征有重要意义。     

uPA和PAI-1在肺纤维化中的作用

慢性炎症和纤维化疾病都以炎性细胞和介质的聚集为特征 ,并且细胞外基质及纤溶酶系统均有明显的改变。目前发现 ,纤溶酶原激活系统的改变是肺纤维化发展中一个非常关键的环节。研究表明各种肺纤维化患者的支气管灌洗液 (BAL)中纤溶酶原活性受到的损害往往是由于尿激酶型纤溶酶原激活物 (uPA)缺失 ,以及纤溶酶原激活因子抑制物 1(PAI 1)表达增加所致。     

急性脑梗死患者凝血纤溶状态及血粘度检测的临床意义

目的研究急性脑梗死患者凝血纤溶状态与血粘度的改变及意义。方法选择30例患者和33例正常人进行凝血因子Ⅷ相关抗原(vWF∶Ag)、抗凝血酶Ⅲ(AT-Ⅲ)含量、组织纤溶酶原激活物(t-PA)及其抑制物(PAI-1)的活性及血粘度的测定。结果患者组vWF∶Ag含量t-PA、PAI-1活性及血粘度测定结果显著高于正常对照组 ,而AT-Ⅲ含量显著低于对照组。结论脑梗死患者急性期血液处于高凝与高粘状态 ,且诸因素相互作用 ,相互促进 ,对本病的发生发展具有重要意义。     

LPS促进HUVECs表达纤溶酶原激活物抑制物1

目的：观察LPS对脐静脉血管内皮细胞(HUVECs)表达组织纤溶酶原激活物(tPA)和纤溶酶原激活物抑制物1(PAI-1)的影响。 方法： 用生长良好的第2、3代HUVECs进行试验。用cell counting kit-8(CCK-8)测定LPS刺激后细胞活性变化；发色底物法测定LPS组和对照组培养液中tPA, PAI-1活性；RT-PCR检测细胞内tPA和PAI-1 mRNA水平。 结果： 与对照组相比，LPS(10 mg/L)对细胞活性没有明显差异。LPS诱导PAI-1活性在24-72 h显著升高(P<0.05),且显著上调PAI-1 mRNA，24 h达到峰值，以后渐降，72 h达到正常水平。而LPS组与对照组tPA活性与tPA mRNA无明显差异(P>0.05)。 结论： LPS(10 mg/L)可显著上调PAI-1 mRNA转录和分泌而不影响tPA mRNA，结果提示LPS可活化内皮细胞，诱发PAI-1 mRNA表达和蛋白分泌而抑制纤溶系统，这有利于微血栓的形成、血栓稳定,血液凝固和DIC发生。     

ACI患者血浆ET-1和t—PA、PAI-1水平的相关性分析

内皮素（Endothelin－1,ET－1）为体内最强的缩血管多肽。纤溶系统在急性脑梗死（ACI）的发生发展中起着十分重要的作用,组织型纤溶酶原激活物（t-PA）和纤溶酶原激活物抑制物-1（PAI-1）的水平是纤溶活性的重要检测指标,     

Tissue plasminogen activator, plasminogen activator inhibitors, and activator-inhibitor complex in liver disease.

AIMS--To identify the relative contribution of plasminogen activators, particularly tissue plasminogen activator (t-PA) and specific plasminogen activator inhibitors (PAI-1, PAI-2), to the fibrinolytic changes associated with various types of liver disease or severe chemical and physical damage to the liver. METHODS--Platelet rich (PRP) and platelet poor plasma (PFP) from patients with alcoholic cirrhosis, primary biliary cirrhosis, hepatic malignancy, or paracetamol overdose, or who were undergoing partial hepatectomy or liver transplantation, were assayed for t-PA, PAI-1, t-PA-PAI-1 complex and PAI-2 antigen values using specific enzyme linked immunosorbent assays (ELISAs) developed in this laboratory. RESULTS--Appreciable increases in the plasma concentration of t-PA, PAI-1, and t-PA-PAI-1 were seen in patients with alcoholic cirrhosis, primary biliary cirrhosis, and hepatic malignancy. Liver damage due to paracetamol overdose and partial hepatectomy both resulted in a striking increase in plasma PAI-1 concentration, although concentrations of t-PA and t-PA-PAI-1 complex were less affected. Concentrations of t-PA, PAI-1, and t-PA-PAI-1 complex returned to near normal values after successful liver transplantation in a patient with chronic active hepatitis. PAI-2 was also detected in several patients with chronic liver disorders. CONCLUSIONS--Haemorrhage due to fibrinolytic bleeding is commonly associated with liver disease. The patients studied here all had appreciable increases in circulating t-PA antigen concentrations. This was associated with increased concentrations of PAI-1 antigen and t-PA-PAI-1 complex and the balance between activator and inhibitor did not result in systemic plasmin generation. Reduced PAI-1 activity in cirrhosis or a critical difference in the ratio of t-PA to PAI-1 concentrations may explain the enhanced plasminogen activator activity previously noted in cirrhosis but not metastatic disease. Reduced hepatic clearance of t-PA and t-PA-PAI-1 complex due to impaired liver function may account for increased concentrations of free and complexed t-PA.     

Plasminogen Activators and Their Inhibitor in Bone Tumors and Tumor-Like Damages

Expression of urokinase- and tissue-type plasminogen activators and their inhibitor PAI-1 in the cytosolic fraction of 20 osteosarcomas, 20 chondrosarcomas, 13 giant-cell bone tumors, 5 Ewing's sarcomas, and 7 osteochondral exostoses was studied by enzyme immunoassay. The content of urokinase-type plasminogen activator increased, while the concentration of tissue-type plasminogen activator decreased in bone tumors of various histological compositions compared to osteochondral exostoses. A positive correlation was found between PAI-1 content and the volume of osteo- and chondrosarcomas. Expression of urokinase-type plasminogen activator increased in patients with primary osteosarcomas characterized by early generalization of the pathological process.     

Tissue- and Urokinase-Type Plasminogen Activators and Type 1 Plasminogen Activator Inhibitor in Melanomas and Benign Skin Pigment Neoplasms

The content of urokinase- and tissue-type plasminogen activators and plasminogen activator inhibitor PAI-1 in the cytosol of primary and metastatic melanomas and benign skin pigment neoplasms was estimated by enzyme immunoassay. It was shown that local growth and invasion of melanomas are related to suppressed expression of tissue plasminogen activator. The content of urokinase plasminogen activator increases in patients with distant metastases and large thickness of the primary tumor.     

Potentiating effect of endothelial cells on astrocytic plasminogen activator inhibitor type-1 gene expression in an in vitro model of the blood–brain barrier

There is accumulating evidence of the importance of cellular communication between the cells that compose the blood-brain barrier (BBB). Astrocytes are known to affect the expression of tissue-type plasminogen activator (t-PA) and its inhibitor plasminogen activator inhibitor type-1 (PAI-1) in endothelial cells. We investigated the influence of endothelial cells on astrocytic gene expression of PAI-1, protease nexin-1 (PN-1) and t-PA using an in vitro model of the BBB. Primary rat astrocyte-enriched cultures were cocultured with primary adult rat brain microvascular endothelial cells on opposite sides of a transwell membrane. After coculturing for 9–11 days, the cultures were treated with lipopolysaccharide (LPS) for 8 h or 24 h. The levels of PAI-1, PN-1 and t-PA mRNA in untreated and treated monocultures and cocultures were analyzed by Real-Time RT-PCR. Cocultivation of astrocytes and endothelial cells increased astrocytic PAI-1 mRNA expression, and this response was further amplified by LPS treatment. The levels of PN-1 and t-PA mRNA expression in astrocytes were unaffected by cocultivation and/or LPS treatment. Analysis of endothelial PAI-1 and t-PA gene expression revealed increased PAI-1 mRNA levels in cocultured cells, whereas t-PA mRNA levels remained unchanged. These results demonstrate that the cocultivation of astrocytes and endothelial cells induces a pronounced increase in astrocytic PAI-1 gene expression, and that this effect is amplified by LPS treatment. These findings imply an important role for intercellular crosstalk in modulating PAI-1 gene expression within the BBB, under both physiologic and pathophysiologic conditions.     

Effects of black cohosh on the plasminogen activator system in vascular smooth muscle cells

Objective

The rhizome of the Cimicifuga racemosa plant (commonly known as black cohosh) has been used for menopausal complaints. Studies regarding the cardiovascular effects of black cohosh are lacking. We investigated the effect of black cohosh on the plasminogen activator system in cultured vascular smooth muscle cells (VSMCs).

Methods

VSMCs were isolated from rat aortae. Expression of plasminogen activator inhibitor type 1 (PAI-1) and tissue-type plasminogen activator (t-PA) proteins were evaluated by Western blot analysis and enzyme-linked immunosorbent assay, respectively. The activities of PAI-1 and t-PA in the conditioned media were assessed by fibrin overlay zymography. A 40% 2-propanol extract of black cohosh was used.

Results

Black cohosh extract (BcEx) stimulated the protein expression of PAI-1, but it did not affect that of t-PA. Vitamin E, a potent antioxidant, inhibited the BcEx-induced increase in PAI-1 expression, while ICI 182,780, an estrogen receptor antagonist, had no effect. Fibrin overlay zymography revealed that BcEx increased the activity of PAI-1 in the conditioned media, while concurrently decreasing that of free t-PA by inducing a binding to PAI-1.

Conclusions

BcEx induces PAI-1 protein expression in the VSMCs likely via an oxidant mechanism. It also stimulates the enzyme activity of PAI-1 and reduces that of free t-PA. These findings suggest that black cohosh might exert a negative influence on fibrinolysis.     

妊娠糖尿病孕妇糖化血红蛋白与部分止凝血指标活性的相关性

目的探讨妊娠糖尿病（GDM）孕妇的部分凝血、纤溶指标活性的变化及其与糖化血红蛋白（GHbA1c）的相关性。方法对正常非孕妇女、正常妊娠妇女（各40例）和GDM孕妇（50例）的GHbA1c、血浆Ⅶc因子（FⅦc）、组织型纤溶酶原激活物（t-PA）及其抑制物（PAI-1）、蛋白C活性依赖凝固时间（PCAT）及抗凝血酶-Ⅲ（AT-Ⅲ）等指标进行检测,并分析糖化血红蛋白与各指标之间的相关性。结果与正常非孕组及正常妊娠组比较,GDM组GHbA1c、FⅦc、PAI-1均显著增高（P〈0．01）,t-PA明显下降（P〈0．01）;正常妊娠组AT-Ⅲ较非孕组呈下降趋势,GDM患者AT-Ⅲ水平、PCAT与正常妊娠组无显著差异。全部GDM患者GHbA1c与t-PA呈负相关（r=-0．607．P〈0．01）,与PAI-1呈正相关（r=0．493,P〈0．01）,与FⅦc活性正相关（r=0．421,P〈0．01）。结论糖尿病孕妇存在着明显的血栓前状态,血糖通过影响纤溶凝血系统功能,导致凝血功能异常,在妊娠糖尿病的发生发展中起着重要的作用。提示应密切关注患者糖化血红蛋白及凝血纤溶指标的变化,预防并发症的发生。