氨氯吡咪对大鼠慢性阻塞性肺疾病模型病理改变的影响

目的观察尿激酶型纤溶酶原激活物（u-PA）抑制剂氨氯吡咪对大鼠慢性阻塞性肺疾病（COPD）模型病理及病理生理改变的影响，探讨u-PA系统成分在COPD发病中的作用。方法健康Wistar大鼠24只随机分为3组：正常对照组、模型组和氨氯吡咪组。7周后检测各组大鼠的肺功能，支气管肺泡灌洗液（BALF）细胞计数及分类，天狼猩红染色观察支气管肺组织的胶原沉积，免疫组化染色观察u-PA、u-PA受体、纤溶酶原激活物抑制物1（PAI-1）的蛋白定位和表达。结果模型组大鼠的呼气阻力显著高于对照组和氨氯吡咪组，0．3s用力呼气容积／用力肺活量、呼气峰流速均显著低于对照组和氨氯吡咪组；模型组大鼠的BALF中自细胞总数、中性粒细胞、单核细胞和巨噬细胞构成比显著高于对照组和氨氯吡咪组；模型组大鼠以I型胶原为主的细胞外基质在气道壁过度沉积，胶原面积显著高于对照组和氨氯吡咪组；模型组大鼠支气管肺组织u-PA、u-PA受体和PAI-1蛋白表达的平均吸光度值[（0．166±0．010）、（0．158±0．024）和（0．171±0．012）]显著高于对照组[（0．137±0．015）、（0．122±0．009）和（0．144±0．005）]及氨氯吡咪组[（0．126±0．004）、（0．120±0．010）和（0．122±0．004）]，且u-PA受体蛋白表达与中性粒细胞构成比呈显著正相关。结论应用u-PA抑制剂氨氯吡咪可显著减轻COPD大鼠的气道炎症和病理结构改变，u-PA系统成分是COPD气道炎症和组织重塑环节中具有关联作用的重要物质。     

尿激酶型纤维蛋白溶解酶原激活物及其受体在支气管哮喘中的表达和意义

目的测定支气管哮喘（哮喘）患者血浆和诱导痰中尿激酶型纤维蛋白溶解酶原激活物及其受体（u-PA、u-PAR）的水平,以探讨其在哮喘发病中的作用。方法用酶联免疫吸附法（ELISA）分别检测29例哮喘急性发作者（发作组）、26例缓解者（缓解组）和15例正常健康者（对照组）血浆和诱导痰中u-PA、u-PAR的水平,并分别进行外周血和诱导痰细胞计数和分类,同期测量肺功能（第一秒用力呼气肺活量占预计值％,FEV．％pred）,分析u-PA、u-PAR与嗜酸性粒细胞（EOS％）、FEV1％pred的相关性。结果发作组和缓解组血浆u-PAR水平[（650±154）ng／L,（677±189）ng／L],较对照组[（478±165）ng／L]明显升高（P〈0．01）;三组血浆u-PA水平[（98±20）ng／L,（90±20）ng／L,（88±23）ng／L]比较差异无统计学意义（P〉0．05）。发作组和缓解组诱导痰u-PAR水平[（766±272）ng／L,（700±271）ng]较对照组（516±197）ng／L明显升高（P〈0．05）;三组诱导痰u-PA水平[（287±235）ng／L,（251±276）ng／L,（239±322）ng／L]比较差异无统计学意义（P〉0．05）。发作组与缓解组u—PA、11-PAR水平与FEV。％pred无明显相关关系（P〉0．05）。发作组与缓解组诱导痰u-PAR水平与诱导痰EOS正相关（r分别为0．796,0．770,P〈0．05）。结论u—PAR参与了哮喘气道慢性炎症的病理生理过程,其作用与嗜酸性粒细胞有关。     

慢性阻塞性肺疾病患者环氧合酶2和基质金属蛋白酶2的表达及其与气流阻塞的关系

目的探讨慢性阻塞性肺疾病(COPD)患者诱导痰中环氧合酶2(COX-2)及基质金属蛋白酶2(MMP-2)的表达及其与气流阻塞的关系。方法COPD组55例(COPD稳定期患者,其中0级12例、Ⅰ级10例、ⅡA级12例、ⅡB级11例和Ⅲ级10例)和正常对照组10名行痰诱导,对痰悬液进行细胞分类计数,应用酶联免疫吸附测定(ELISA)法检测诱导痰上清液中前列腺素E2(PGE2)和MMP2浓度,Westernblot法测定诱导痰细胞中COX-2蛋白表达。结果(1)COPD组诱导痰中细胞总数、肺泡巨噬细胞(AM)数和中性粒细胞(Neu)数较正常对照组显著增高(P<0.05或P<0.01)。AM、Neu与第一秒用力呼气容积占预计值%(FEV1占预计值%)、一秒率(FEV1/FVC)分别呈负相关(r=-0.280、P<0.05,r=-0.345、P<0.01;r=-0.677,r=-0.773,P均<0.01)。(2)Westernblot显示COPD组患者诱导痰细胞中COX-2蛋白表达(57±8)显著高于正常对照组(83±10,P<0.05)。(3)COPD各组诱导痰PGE2浓度[分别为(111±17)、(117±23)、(118±29)、(153±24)、(194±28)ng/L]显著高于正常对照组[(81±18)ng/L,P均<0.01],且与FEV1占预计值%、FEV-1/FVC呈负相关(r=-0.748,r=-0.750,P均<0.01),与MMP-2浓度呈正相关(r=0.775,P<0.01)。COPD各组诱导痰MMP2浓度[(4.0±0.9)、(4.5±1.5)、(7.7±3.1)、(11.9±3.5)、(18.5±5.     

肝硬化患者尿激酶型纤溶酶原激活物及其受体测定的临床意义

目的检测肝硬化患者血浆中尿激酶型纤溶酶原激活物(u-PA)及其受体(u-PAR)的含量,分析代偿期和失代偿期肝硬化患者纤溶活化的变化情况。方法 ELISA法检测48例肝硬化和30名健康志愿者的血浆中u-PA及其受体的含量。结果失代偿期肝硬化患者u-PA(1362±481ng.l~(-1))及u-PAR(1037±357ng.l~(-1))均明显高于对照(P<0.05,P<0.05),且u-PA高于代偿期肝硬化患者(P<0.05)结论肝硬化患者存在明显的纤溶活性增强,并随病情的加重而增加。     

溶栓及抗凝药物对内皮细胞尿激酶型纤溶酶原激活物系统和组织因子表达的影响

目的 探讨重组尿激酶原,重组组织型纤溶酶原激活物及肝素对肺动脉内皮细胞尿激酶型纤溶酶原激活物(urokinase type plasminogen activator,u-PA)系统和组织因子(tissue factor,TF)表达的影响.方法 采用体外培养的人肺动脉内皮细胞,待细胞长满后饥饿12h,换液并加入不同药物与细胞孵育12h.根据不同的药物处理方式分为五组:正常对照组;凝血酶(1IU/ml)组;凝血酶(1IU/ml)+重组尿激酶原(150IU/ml)组;凝血酶(1IU/ml)+重组组织型纤溶酶原激活物(150IU/ml)组;凝血酶(1IU/ml)+低分子肝素(10IU/ml)组.孵育结束后,收集培养液,1000r/min离心10min.ELISA法检测细胞培养液中u-PA、u-PA受体(u-PA receptor,u-PAR)、纤溶酶原激活物抑制物-1(plaminogen activator inhibitor-1,PAl-1)和TF的含量.结果 凝血酶(1IU/ml)组细胞培养液中PAI-1的含量较正常对照组显著增高,u-PA、u-PAR和TF的含量较正常对照组无显著改变.重组尿激酶原组细胞培养液中u-PA和u-PAR的含量较凝血酶组显著增加,PAI-1的含量较对照组显著下降,TF的含量较对照组无显著改变.重组组织型纤溶酶原激活物组细胞培养液中u-PA的含量较凝血酶组显著增加,PAI-1的含量较对照组显著下降,TF的含量较凝血酶组显著下降.低分子肝素组细胞培养液中TF的含量均较凝血酶组及对照组明显下降,u-PA、u-PAR和PAI-1较对照组无显著改变.结论 重组尿激酶原、重组组织型纤溶酶原激活物及低分子肝素都能影响人肺动脉内皮细胞的内源性纤溶和抗凝功能.重组尿激酶原能够促进肺动脉内皮细胞u-PA和u-PAR的表达和释放,抑制PAI-1的表达和释放.重组组织型纤溶酶原激活物不仅能够促进肺动脉内皮细胞u-PA的表达和释放,抑制PAI-1的表达和释放,而且能够抑制TF的表达和释放.肝素主要是抑制肺动脉内皮细胞表达和释放TF.     

高血压并发不同程度糖代谢异常血浆PAI-1水平变化

目的探讨高血压患者并发不同程度糖代谢异常血浆纤溶酶原激活物抑制剂-1(PAI-1)的相关性及其影响。方法160例高血压病患者,根据空腹血糖(FPG)和OGTT检查2h血糖(2HPG)试验结果分为三组:糖耐量正常(NGT)组、糖耐量异常(IGT)组和糖尿病(DM)组。用酶联免疫双抗体吸附法(ELISA法)测定三组患者血浆PAI-1抗原。结果①单因素方差分析(ANOVA)显示,NGT、IGT和DM三组PAI-1水平差异有统计学意义[(30.25±6.17)ng/ml、(43.12±5.52)ng/ml和(55.04±8.03)ng/ml;P<0.01]。②以PAI-1与年龄、收缩压(SBP)、舒张压(DBP)、FPG、2HPG作直线回归分析,能进入该方程的变量为年龄、SBP、DBP、2HPG。结论高血压患者伴发糖代谢异常及其严重程度与PAI-1升高正相关;年龄、SBP、DBP、2HPG为PAI-1独立影响因素。     

化瘀通络中药对5/6肾切除大鼠纤溶系统的影响

目的 观察化瘀通络中药肾络通对5/6肾切除大鼠纤溶系统的影响.方法 46只健康雄性SD大鼠随机分为假手术组、模型组、苯那普利组、肾络通组.复制5/6肾切除肾衰大鼠模型,采用免疫组织化学及原位杂交方法检测各组大鼠肾组织纤溶酶原激活物组织型(t-PA)、纤溶酶原激活物尿激酶型(u-PA)、纤溶酶原激活物的抑制物-1(PAI-1)及PAI-1 mRNA的表达,并进行病理学检测.结果 模型组t-PA、u-PA的相对含量及ILD值均显著低于假手术组(P＜0.01),而PAI-1及PAI-1 mRNA则显著高于假手术组(P＜0.01);肾络通组、苯那普利组与模型组相比,t-PA、u-PA的相对含量及ILD值均明显升高(P＜0.01或P＜0.05),而PAI-1及PAI-1 mRNA则明显降低(P＜0.01或P＜0.05).结论 化瘀通络中药肾络通能纠正5/6肾切除大鼠纤溶系统的紊乱,延缓肾脏疾病的进程.     

血管紧张素Ⅱ和卡托普利、缬沙坦对人脐静脉内皮细胞PAI-1、tPA蛋白表达的影响

目的研究血管紧张素Ⅱ(Ang Ⅱ)和血管紧张素转换酶抑制剂(ACEI),卡托普利和Ang Ⅱ 1型受体(AT-1)拮抗剂缬沙坦对人脐静脉内皮细胞(HUVECs)1型纤溶酶原激活物抑制剂(PAI-1)、组织型纤溶酶原激活剂(tPA)蛋白的释放及活性的影响.方法将不同浓度的Ang Ⅱ(10-6～10-9 mol/L)与HUVECs共同孵育24 h,以及将10-6 mol/L的Ang Ⅱ与HUVECs作用不同时间(0、4、8、12、24 h)后,用细胞酶联免疫法和发色底物法分别检测细胞培养液中PAI-1、tPA的含量及活性,并观察卡托普利和缬沙坦干预后的影响.结果 10-6mol/L Ang Ⅱ作用HUVECs 24 h后,可使细胞分泌的PAI-1含量与对照组相比明显增高(280±15.60 vs 83.33±10.56) ng/mL,P<0.01),PAI-1活性明显增加(9.25±0.39 vs 7.53±0.33) IU/mL,P<0.01),Ang Ⅱ虽也可刺激tPA含量增加(101.67±3.78 vs 70±5.62) ng/mL,(P<0.01),但PAI-1的增量是tPA增量的6～7倍(Δ196.67±21.34 vs Δ31±6.50) ng/mL,(P<0.01),Ang Ⅱ对tPA活性无影响(0.97±0.05 vs 0.95±0.08) ng/mL,(P>0.05);缬沙坦可显著抑制Ang Ⅱ的促PAI-1分泌作用(212.67±5.38 vs 290±6.57) IU/mL,(P<0.01),而卡托普利对Ang Ⅱ的促PAI-1分泌作用无明显抑制作用(278.33±9.16 vs 290±6.57) IU/mL,(P>0.05).结论 Ang Ⅱ可促使HUVECs分泌PAI-1,并使其活性增加;Ang Ⅱ亦可刺激tPA分泌,但作用弱于PAI-1,对其活性无明显影响.缬沙坦可抑制Ang Ⅱ促HUVECs分泌PAI-1的作用;卡托普利的作用不显著.     

胰岛素抵抗和纤溶功能紊乱与急性冠状动脉综合征的相关性研究

目的探讨胰岛素抵抗(IR)、纤溶功能紊乱与急性冠状动脉综合征(ACS)患者冠状动脉病变严重程度的关系及对患者近期预后的预测价值。方法连续收集2008年2月至2009年7月在我院心内科住院并诊断ACS的患者165例,按IR指数(HOMA指数)水平分为两组,IR组(HOMA-IR>5)80例,非IR组(HOMA-IR≤5)85例,分析两组患者间纤溶功能指标、冠状动脉病变严重程度的差异,并观察纤溶功能紊乱及IR对接受经皮冠状动脉介入治疗(PCI)的ACS患者近期(6个月内)预后的影响。结果与非IR组比较,IR组ACS患者组织纤溶酶原激活物(t-PA)水平较低[(8.56±2.39)μg/L比(11.06±2.12)μg/L,P<0.01],纤溶酶原激活物抑制物1(PAI-1)水平较高[(36.21±9.62)μg/L比(22.12±3.97)μg/L,P<0.01],并且冠状动脉病变的严重程度增加:多支病变[26例(32.5%)比13例(15.3%),P<0.05];B2/C型病变[29例(36.3%)比17例(20.0%),P<0.05];Gensini积分(55.63±14.24比44.11±11.42,P<0.01)。IR与PAI-1呈正相关(r=0.293,P<0.01);多因素Logistic回归分析显示,PAI-1及IR均是ACS患者近期预后的独立预测因子(P<0.05)。结论 ACS患者存在纤溶功能紊乱或IR时,冠状动脉病变更为严重,PAI-1水平及IR对ACS患者的近期预后有预测价值。     

血浆纤溶酶原激活物抑制物-1基因4G/5G多态性及其抗原与冠心病的关系

目的探讨纤溶酶原激活物抑制物-1(PAI-1)与冠心病的关系及其对冠状动脉病变程度的预测价值.方法选择345例非糖尿病的住院患者(其中295例已行冠状动脉造影),分为对照组、心绞痛组及陈旧性心肌梗塞(OMI)组,通过等位基因特异引物聚合酶链反应法检测PAI-1基因4G/5G多态性,并测定血浆PAI-1抗原水平.为分析PAI-1基因型与冠心病、心肌梗塞的相关性,将心绞痛组与OMI组患者合称冠心病者,对照组与心绞痛组患者合称非心肌梗塞者.冠心病患者又分为稳定性心绞痛(SAP)者和不稳定性心绞痛(UAP)者.结果血浆PAI-1抗原水平在对照组、心绞痛组及OMI组间无统计学差异.UAP患者与SAP相比,PAI-1抗原水平显著升高,有显著性差异(25.0±7.2ng/ml比22.3±7.1 ng/ml,P<0.05),经Logistic回归分析,血浆PAI-1抗原水平与UAP仍有显著性相关,调整后的OR值为1.83(P=0.05).冠心病者4G和5G等位基因频率为56%和44%;对照组频率为62%和38%,冠心病者与对照组间无显著性差异.经一元直线相关分析发现,PAI-1基因型与PAI-1抗原水平间无相关性(P>0.05).PAI-1基因型分布及血浆水平均与冠状动脉病变支数无关.结论血浆PAI-1抗原水平升高可能与UAP有关,但PAI-1基因4G/5G多态性与血浆抗原水平及冠心病、心肌梗塞均无显著相关,且对冠状动脉病变范围无预测价值.     

Sputum cathelicidin, urokinase plasminogen activation system components, and cytokines discriminate cystic fibrosis, COPD, and asthma inflammation

BACKGROUND: Interest in airways inflammatory disease has increasingly focused on innate immunity. We investigated several components of innate immunity in induced sputum of patients with cystic fibrosis (CF), COPD, and asthma, and healthy control subjects. METHODS: Twenty eight patients with mild CF lung disease (age > or = 12 years; FEV1, 74 +/- 3% predicted [mean +/- SE]), 74 adults with COPD (FEV1, 55 +/- 2% of predicted), 34 adults with persistent asthma (FEV1, 66 +/- 2% of predicted), and 44 adult control subjects (FEV1, 85 +/- 1% of predicted) were studied while in stable clinical condition. Levels of sputum interleukin (IL)-8, IL-10, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, human cationic antimicrobial protein 18 (CAP18), urokinase-type plasminogen activator (uPA), uPA receptor (uPAR), and plasminogen activator inhibitor (PAI)-1 were determined. Cell sources were investigated by flow cytometry and immunohistochemistry. Spirometry was performed prior to sputum induction. RESULTS: CF patient sputum showed greatest increase in IL-8 compared to that of patients with COPD and asthma (which were also greater than control subjects), and elevated levels of TNF-alpha and IL-10 compared to other groups. There were no differences in IFN-gamma. CAP18 levels were elevated in CF and COPD patients compared to control subjects, while asthma patients had reduced CAP18 levels. uPA levels were similar but uPAR was elevated in CF and COPD patients more so than in asthma patients, while PAI-1 levels were elevated in all three disease groups. CAP18 localized to neutrophil secondary granules; neutrophils were also sources of IL-8 and PAI-1. CAP18 and PAI-1 negatively correlated with pulmonary function. CONCLUSION: Induced-sputum innate immune factor levels discriminate inflammatory changes in CF, COPD, and asthma, suggesting potential roles in pathophysiology and as well as providing disease-specific biomarker patterns.     

Interleukin-1beta regulates urokinase plasminogen activator (u-PA), u-PA receptor, soluble u-PA receptor, and plasminogen activator inhibitor-1 messenger ribonucleic acid expression in cultured human endometrial stromal cells

The interleukin-1 (IL-1) system plays an integral role in local intercellular interactions during implantation. In addition, the plasminogen activator system, especially urokinase plasminogen activator (u-PA), plasminogen activator inhibitor (PAI-1), and u-PA receptor (u-PAR), are crucial during embryo implantation. Decidualization and implantation are complex processes dependent upon several proteases, including u-PA, and IL-1 is known to affect PA activity in several cell types. We investigated the role of IL-1beta in regulating u-PA, PAI-1, u-PAR, and soluble u-PAR messenger ribonucleic acid (mRNA) expression in cultured human endometrial stromal cells using quantitative competitive PCR. For confirmation of the mRNA data, we measured PAI-1 and u-PAR protein by enzyme-linked immunosorbent assay. Confluent stromal cell cultures treated with progesterone and estradiol for 9 days were stimulated with IL-1beta, and IL-1beta plus IL-1beta antibody for an additional 24 h. Total RNA was extracted, reverse transcribed, and coamplified using quantitative and competitive PCR with internal standards. IL-1beta increased PAI-1, u-PAR, and soluble u-PAR expression in a dose-dependent manner, and this result was reversed by anti-IL-1beta antibody treatment. u-PA mRNA expression was not dependent on IL-1beta. These results suggest that IL-1 may be important in regulating PAI-1 and u-PAR during stromal cell decidualization before implantation.     

Interleukin-4 Modulation of Platelet-Derived Growth Factor–Induced Smooth Muscle Cell Urokinase Plasminogen Activator

Platelet-derived growth factor (PDGF) stimulates smooth muscle cell (SMC) migration owing to stimulation of SMC tissue plasminogen activator (t-PA) production. In this study we examined the effects of the T-cell lymphokine interleukin-4 (IL-4) on PDGF induction of human aortic SMC antigen levels of urokinase-type plasminogen activator (u-PA) and those of plasminogen activator inhibitor-1 (PAI-1), the endogenous inhibitor of t-PA and u-PA, measured by enzyme-linked immunosorbent assays (ELISAs). u-PA antigen levels from human aortic SMC incubated with PDGF 100 ng/mL and IL-4 500 U/mL were significantly greater than those incubated with PDGF 100 ng/mL alone. Coincubation of PDGF with IL-4 did not significantly increase SMC u-PA antigen levels in cellular lysates. Coincubation with PDGF 100 ng/mL and IL-4 500 U/mL did not significantly affect SMC PAI-1 antigen levels in conditioned media or cellular lysates. Therefore, interleukin-4 modulates vascular SMC u-PA production induced by PDGF.     

The fibrinolytic system components are increased in systemic sclerosis and modulated by Alprostadil (alpha1 ciclodestryn)

OBJECTIVES: To evaluate urokinase plasminogen activator (u-PA), urokinase plasminogen activator soluble receptor (su-PAR), plasminogen activator inhibitor 1 (PAI-1) and tissue plasminogen activator (t-PA) plasma levels in SSc patients (pts) versus healthy controls and their modulation by intravenous alphacyclodestrine (Alprostadil). METHODS: Plasma levels of u-PA, su-PAR, PAI-1 and t-PA were measured in 40 SSc (34 lSSc and 6 dSSc) pts and in 30 healthy controls. In SSc, blood was drawn before and after 3 consecutive daily of Alprostadil infusion (60 mg in 250 cc NaCl 0.9%). RESULTS: In SSc su-PAR basal levels were higher than controls (7.48 +/- 2.5 vs 4.69 +/- 0.4 ng/ml; p = 0.001) and were significantly reduced by Alprostadil (5.93 +/- 1.7; p = 0.002), but remain higher than controls (p = 0.03). u-PA basal levels were higher than controls (3.78 +/- 1.5 vs 1.29 +/- 0.3 ng/ml; p < 0.001) and were reduced by Alprostadil (2.39 +/- 1.7; p < 0.001) to control levels. SSc PAI-1 basal levels were lower than controls (31.60 +/- 7.7 vs 48.30 +/- 6.8 ng/ml; p < 0.001) and increased by Alprostadil (34.66 +/- 5.4; p = 0.04), but lower than controls (p < 0.001). SSc t-PA basal levels were higher in respect to controls (1645.81 +/- 792.7 vs 571.95 +/- 75.5 pg/ml; p < 0.0001) and reduced by Alprostadil (1318.06 +/- 603.5; p = 0.04), but still higher than controls (p = 0.001). CONCLUSION: Fibrinolysis were increased in SSc. Infusions of Alprostadil modulate u-PA, su-PAR, PAI-1 and t-PA, restoring near normal levels. In SSc, fibrinolysis system may become a potential target for new therapies.     

DIFFERENCE IN EXPRESSION OF THE PLASMINOGEN ACTIVATION SYSTEM IN SYNOVIAL TISSUE OF PATIENTS WITH RHEUMATOID ARTHRITIS AND OSTEOARTHRITIS

Protcolytic joint destruction in inflammatory and non-inflammatoryarthropathy is believed to be mediated, at least in part, bythe plasminogen activation (PA) system. To further investigatepossible involvement of the PA system, we quantified immunoreactiveurokinase-type plasminogen activator (u-PA), tissue-type plasminogenactivator (t-PA), both plasminogen activator inhibitors (PAI-1and PAI-2) and u-PA-receptor (u-PAR) in synovial tissue extractsof 14 patients with rheumatoid arthritis (RA) and 12 with osteoarthritis(OA). u-PA, PAI-1, PAI-2 and u-PAR concentrations were significantlyhigher in RA than in OA patients. t-PA antigen levels were significantlylower in RA than in OA synovial tissue extracts. Immunohistochemistrywas performed to compare the distribution and staining intensityof these components in samples of RA and OA synovial tissue.Intense immunostaining of u-PA, u-PAR, PAI-1 and, to a lesserdegree, PAI-2 was observed predominantly in the synovial liningof RA patients. In OA patients, u-PA, PAI-1, PAI-2 and u-PARwere barely detectable. t-PA immunostaining was restricted tothe endothelial side of vascular walls in both groups. We concludethat the observed increase of u-PA, u-PAR and PAI expression,distributed mainly in the synovial lining area of proliferativeand invasively growing synovial tissue in RA patients, supportsa pathogenic role for the PA system in destructive arthritis.Depressed t-PA-mediated plasminogen activation might contributeto delayed intra-articular fibrin removal. KEY WORDS: Urokinase, Plasminogen activation, Immunohistochemistry, Rheumatoid arthritis, Osteoarthritis     

Antithrombotic regulation in human endothelial cells by fibrinolytic factors

Vascular endothelial cells (ECs) modulate the blood fibrinolytic system by secreting tissue-type plasminogen activator (t-PA), urokinase-type plasminogen activator (u-PA), and their inhibitor, type-1 plasminogen activator inhibitor (PAI-1). ECs also express t-PA receptors (t-PAR) and u-PA receptors (u-PAR) on their cell surfaces, assembling both enzymes to regulate the cellular fibrinolytic activity. In addition, ECs modulate these factors in response to several stimuli. Fibrin clots on ECs induce the up- and downregulation of t-PA and PAI-1 production, respectively, thus causing an effective lysis of the fibrin clot. Heat shock (43 degrees C) increases the expression of u-PA, t-PA, PAI-1, and u-PAR by which ECs become more fibrinolytic around the cells. Furthermore, because ECs possess t-PAR and u-PAR on their cell surfaces, the binding of t-PA and u-PA is a critical event, which affords ECs the localized and condensed fibrinolytic potential. Therefore, ECs play a central role in antithrombotic activity by regulating the levels of these fibrinolytic factors.     

Interleukin-4 stimulates expression of urokinase-type-plasminogen activator in cultured human foreskin microvascular endothelial cells

The effect of interleukin-4 (IL-4) on the fibrinolytic system of human microvascular and macrovascular endothelial cells in culture was studied. Only foreskin microvascular endothelial cells (EC) responded to IL-4 treatment with a dose- and time-dependent increase in urokinase- type plasminogen activator (u-PA) (control: 3.0 +/- 0.8 ng/10(5) cells/24 h; 200 U/mL IL-4: 6.7 +/- 0.8 ng/10(5) cells/24 h), whereas human macrovascular EC remained unaffected. A maximum effect was achieved with 200 U/mL IL-4. Little u-PA activity was detected in the conditioned media of human foreskin microvascular EC (HFMEC) treated without and with IL-4 before plasmin treatment (control: 0.03 +/- 0.003 IU/10(5) cells/20 h; 200 U/mL IL-4: 0.09 +/- 0.007 IU/10(5) cells/20 h). These values increased to 0.18 +/- 0.02 IU/10(5) cells/20 h and 0.53 +/- 0.04 IU/10(5) cells/20 h, respectively, after plasmin treatment, indicating that u-PA is released by HFMEC predominantly in its inactive precursor form single-chain u-PA (scu-PA). u-PA activity increased also in the cell lysates of HFMEC up to 2.5-fold after IL-4 treatment. Plasminogen activator inhibitor type-1 (PAI-1) levels produced by HFMEC remained unaffected by IL-4, whereas tissue-type plasminogen activator (t-PA) levels were slightly decreased when HFMEC were treated with IL-4. These findings were also reflected in the specific mRNA levels as determined by Northern blotting. u-PA-specific mRNA increased significantly in HFMEC in the presence of IL-4, whereas t-PA mRNA and PAI-1-specific mRNA in HFMEC and u-PA specific mRNA in human saphenous vein EC (HSVEC) remained unaffected by IL-4 treatment. Our findings suggest a role for IL-4 in the process of angiogenesis, in addition to its known proliferative effect on human microvascular EC, by increasing the fibrinolytic potential of such EC, thereby facilitating extracellular proteolysis and cell migration.