CFL1RNAi慢病毒的构建及其对人脐静脉内皮细胞的增殖抑制作用

目的 观察干扰CFL1对HUVEC的增殖抑制作用。方法 以cfl1基因为模板,设计RNA干扰靶点,构建cfl1基因RNAi慢病毒; 慢病毒感染人脐静脉内皮细胞HUVEC后采用realtimePCR鉴定CFL1RNAi慢病毒感染效果,采用CCK-8法检测HUVEC细胞的增殖抑制情况。结果 CFL1RNAi慢病毒干扰HUVEC细胞后realtimePCR证实CFL1 RNAi慢病毒可下调cfl1基因的表达; CCK-8法证实cfl1基因表达下调可抑制HUVEC细胞的增殖。结论 CFL1 RNAi慢病毒感染HUVEC细胞后可明显抑制cfl1基因表达,抑制HUVEC细胞增殖。     

人脐静脉内皮细胞单层通透性改变的效应因子

背景：外源性刺激引起血管屏障功能损伤的分子机制是血管病理生理学尚未阐明的热点问题之一。 目的：探讨炎症递质脂多糖诱导的人脐静脉内皮细胞单层通透性改变的效应分子,寻找有效治疗靶点。 方法：应用脂多糖刺激并观察人脐静脉内皮细胞骨架蛋白F-actin和细胞单层通透性的改变。应用荧光免疫组化和Western blot方法检测脂多糖刺激前后细胞中RhoA和SRF等信号分子的改变。并通过阻断实验证实RhoA-SRF信号通路的作用。 结果与结论：100 µg/L脂多糖刺激6 h可引起人脐静脉内皮细胞中F-actin快速重构并形成大量应力纤维,细胞单层通透性明显增强。细胞中活化RhoA的表达明显增加,SRF发生明显的入核转位现象。应用特异性分子抑制剂Y27632抑制RhoA的活化后,细胞中F-actin重构现象消失,细胞单层通透性增加也受到明显抑制,SRF蛋白发生明显的出现转位。而应用Latrunculin B抑制脂多糖刺激的人脐静脉内皮细胞中F-actin应力纤维形成,对抗通透性增加,但RhoA活化未受到干扰,SRF入核现象则受到抑制。提示RhoA-SRF通路的活化介导了脂多糖诱导的人脐静脉内皮细胞中F-actin重构和内皮单层通透性增加,特异性抑制F-actin也可以阻断脂多糖引起的血管内皮单层通透性增加,同时反馈抑制SRF的入核活化现象。     

推拿扌衮法样刺激对人脐静脉内皮细胞内钙离子浓度的影响

背景：迄今对推拿㨰法作用机制的研究多着眼于软组织、骨关节、神经、血管等宏观层面,还需要从微观细胞学水平对手法力学刺激钙离子通道引发的效应机制进行研究。 目的：观察推拿扌衮法样刺激对人脐静脉内皮细胞内钙离子浓度的影响。 方法：将正常培养和缺氧培养的人脐静脉内皮细胞均分为对照组、推拿组、维拉帕米组。对照组细胞不做任何处理,推拿组细胞用Fluo-3/AM标记后给予手法样压力刺激,压力大小为0.4 kg,频率120次/min,时间1 min;维拉帕米组细胞用Fluo-3/AM标记后,先加入终浓度为10-5 mol/L的维拉帕米,然后给与同样的㨰法样刺激。各组细胞在处理前后分别采用共聚焦激光扫描显微镜观察并测定细胞荧光强度进行比较。 结果与结论：手法样刺激和缺氧环境均可引起人脐静脉内皮细胞内游离钙离子浓度升高,但这两种促进人脐静脉内皮细胞内游离钙离子浓度升高的作用均能够被钙离子拮抗剂维拉帕米所抑制。由此推测,推拿扌衮法的作用机制是通过机械刺激激活钙离子通道,引发细胞钙离子内流,促使细胞内游离钙离子浓度升高,进而启动并产生后续的生物学治疗效应。     

纤维蛋白原和纤维蛋白及其降解产物对共培养人脐静脉内皮细胞趋化迁移的影响

目的:研究不同浓度纤维蛋白原(Fg)、纤维蛋白(Fb)及其降解产物(FDPs)对人脐静脉内皮细胞(HUVECs)/平滑肌细胞(SMCs)共培养模型中HUVECs趋化和迁移的影响。方法:以Transwell膜为载体,建立原代培养的HUVECs与兔SMCs共培养体系,应用不同浓度的Fg、Fb和FDPs干预共培养体系,观察HUVECs趋化(通过Transwell膜装置)和迁移(通过细胞刮伤模型)情况。结果:共培养的HUVECs和SMCs在Transwell膜上生长良好,膜两侧的HUVECs和SMCs可以发生细胞连接。Fg≥3.0 mg·mL-1呈浓度依赖性地促使HUVECs的趋化和迁移。Fb≥1.5 mg·mL-1时呈浓度依赖性地促使HUVECs的趋化和迁移数增加(P<0.05)。FDPs≥0.5 mg·mL-1时HUVECs的趋化和迁移数明显增加(P<0.05)。结论:利用Transwell膜建立的HUVECs/SMCs共培养体系能较好地模拟血管壁的结构关系,为进一步开展相关研究奠定了细胞模型的基础。一定浓度的Fg、Fb及其FDPs可以促进HUVECs趋化与迁移过程,在动脉粥样硬化的发生发展中起重要作用。     

辛伐他汀抑制高糖诱导人脐静脉内皮细胞的凋亡

背景：他汀类药物对血管内皮细胞的凋亡是否有影响目前尚不明确。 目的：探讨辛伐他汀对高糖诱导的人脐静脉内皮细胞凋亡的影响。 方法：用DMEM细胞培养液培养人脐静脉内皮细胞,将细胞分成空白对照组、高糖组和高糖+辛伐他汀组,用四甲基偶氮唑蓝比色法测定人脐静脉内皮细胞的存活率,流式细胞仪和Western blot分别检测细胞早期凋亡率及P53蛋白表达。 结果与结论：高糖组及高糖+辛伐他汀组细胞增殖率较空白对照组明显降低(P < 0.01),而高糖组细胞增殖率较高糖+辛伐他汀组亦降低(P < 0.01);高糖组P53蛋白表达量及凋亡率较空白对照组及高糖+辛伐他汀组明显增加(P < 0.01),高糖+辛伐他汀组P53蛋白表达及凋亡率亦明显高于空白对照组(P < 0.01)。表明高糖可通过促进促凋亡蛋白P53的表达进而促进人脐静脉内皮细胞的凋亡,而辛伐他汀可抑制此作用。     

脑源性微囊泡对脐静脉内皮细胞骨架的影响研究

目的探讨脑源性微囊泡(BDMVs)对脐静脉内皮细胞骨架的影响。方法体外制备BDMVs,并予透射电镜观察及粒径检测。将PKH26荧光染料标记的BDMVs与脐静脉内皮细胞共培养0.5 h、1 h、2 h后,应用流式细胞术检测不同时间点的脐静脉内皮细胞吞噬BDMVs情况。将体外常规培养的脐静脉内皮细胞分为对照组、BDMVs组(加入终浓度1.5×10^7/mL的BDMVs处理细胞)及尼莫地平组[予2μg尼莫地平(0.2 mg/mL)预处理10 min后加入终浓度1.5×10^7/mL的BDMVs处理细胞],应用激光共聚焦显微镜观察罗丹明标记鬼笔环肽染色后各组脐静脉内皮细胞中纤维型肌动蛋白的荧光强度及应力纤维数目。结果透射电镜下可见体外制备的BDMVs具有完整的膜结构,粒径范围为100~1000 nm。流式细胞术检测显示,吞噬BDMVs的脐静脉内皮细胞比例随培养时间的延长呈时间依赖性升高(0.5 h:22.7%±1.2%;1 h:52.3%±1.3%;2 h:71.6%±1.9%),各时间点间两两比较差异均有统计学意义(P<0.05)。激光共聚焦显微镜观察显示,与对照组相比,BDMVs组中纤维型肌动蛋白的荧光强度明显升高且应力纤维数目明显增多增粗;而与BDMVs组相比,尼莫地平组中纤维型肌动蛋白的荧光强度明显降低且应力纤维数目明显减少变细。结论脐静脉内皮细胞吞噬BDMVs的作用随时间延长而增强,且吞噬BDMVs后可导致细胞骨架重构,而尼莫地平可部分阻断该作用。     

蜂胶黄酮对人脐静脉内皮细胞基质金属蛋白酶9的影响

背景：研究表明，基质金属蛋白酶9与动脉粥样硬化斑块的稳定性有关，蜂胶黄酮具有抗动脉粥样硬化的作用。 目的：拟证实蜂胶黄酮对人脐静脉内皮细胞基质金属蛋白酶9表达的影响。 设计、时间及地点：对比观察。实验于2008-01/08在山东泰山医学院生命科学研究所完成。 材料：蜂胶黄酮由泰山医学院生命科学研究所实验室提取；出生1 h内新生儿脐带由山东泰安市中心医院提供，产妇知情同意。 方法：进行人脐静脉内皮细胞的体外培养和鉴定。按四甲基偶氮唑盐实验筛选的浓度，分别加入25，50，100，200 mg/L不同剂量的蜂胶黄酮处理细胞24 h，以空白组做对照。 主要观察指标：免疫细胞化学染色和ELISA法测定蜂胶黄酮对基质金属蛋白酶9表达的影响。 结果：不同剂量的蜂胶黄酮作用人脐静脉内皮细胞24 h后均能明显抑制细胞基质金属蛋白酶9的表达，并且随着浓度的升高抑制作用明显增强。 结论：蜂胶黄酮能明显降低人脐静脉内皮细胞基质金属蛋白酶9的表达。     

纤维蛋白(原)及其降解产物对共培养人脐静脉内皮细胞的细胞间黏附分子-1表达的影响

目的探讨纤维蛋白原(Fg)、纤维蛋白(Fb)及其降解产物(FDPs)对人脐静脉内皮细胞(HU-VECs)/兔平滑肌细胞(SMCs)共培养模型中细胞间黏附分子-1(ICAM-1)表达的影响。方法建立原代HU-VECS与兔SMC共培养体系,根据干预物及其浓度的不同分为Fg、Fb、FDPs组及相应的0 mg/ml、0.5 mg/ml、3.0 mg/ml和6.0 mg/ml亚组。应用核因子B抑制蛋白(I-B)拮抗剂BAY 11-7082、蛋白激酶C(PKC)拮抗剂Staurosporine分别对0.5 mg/ml、3.0 mg/ml和6.0 mg/ml亚组进行干预。采用反转录(RT)-PCR法检测HU-VECS内ICAM-1 mRNA水平;酶联免疫吸附法(ELISA)检测培养上清液的ICAM-1蛋白含量。结果 Fg 3.0mg/ml和6.0 mg/ml亚组ICAM-1 mRNA水平和蛋白含量显著高于0 mg/ml亚组及相应浓度Fg+BAY 11-7082亚组(均P<0.05);Fg 3.0 mg/ml亚组ICAM-1 mRNA水平和蛋白含量显著高于3.0 mg/ml+Staurosporine亚组(均P<0.05)。Fb 6.0 mg/ml亚组ICAM-1 mRNA水平显著高于0 mg/ml、6.0 mg/ml+BAY11-7082和6.0 mg/ml+Staurosporine亚组(均P<0.05),但Fb 6.0 mg/ml亚组ICAM-1蛋白含量显著高于0 mg/ml亚组(P<0.05)。FDPs 6.0 mg/ml亚组ICAM-1 mRNA水平和蛋白含量显著高于0 mg/ml、相应浓度BAY11-7082和Staurosporine亚组(均P<0.05)。结论中、高浓度Fg、Fb、FDPs能上调血管内皮细胞ICAM-1的表达。     

E1A激活基因细胞阻遏子蛋白在人脐静脉内皮细胞凋亡中的作用

背景：研究内皮细胞凋亡的机制及其与动脉硬化形成的关系将为动脉粥样硬化的防治提供新的思路。而E1A激活基因的细胞阻遏子蛋白在内皮细胞凋亡中的作用,目前尚未见报道。 目的：探讨E1A激活基因的细胞阻遏子蛋白在去血清诱导的人脐静脉内皮细胞凋亡中的作用及其调控机制。 时间及地点：实验于2007-10/2008-12在解放军沈阳军区总医院全军心血管病研究所实验室完成。 材料：人脐静脉内皮细胞,Phoenix amphotropic 293细胞,pLNCX-CREG和pLNCX-GFP反转录病毒真核表达载体。 方法：采用持续去血清培养的方法诱导内皮细胞凋亡,用TUNEL染色和Western blot检测去血清饥饿24,48,72 h后各实验组细胞中cleave-caspase3表达;用pLNCX-CREG和pLNCX-GFP反转录病毒真核表达载体转染人脐静脉内皮细胞,并筛选稳定表达的细胞克隆;应用Western blot检测E1A激活基因的细胞阻遏子蛋白的表达,并进一步应用流式双荧光染色分析E1A激活基因的细胞阻遏子蛋白过表达在去血清诱导的人脐静脉内皮细胞凋亡中的作用。 主要观察指标：cleave-caspase3表达量,人脐静脉内皮细胞凋亡率。 结果：成功构建了E1A激活基因细胞阻遏子过表达的人脐静脉内皮细胞模型,证实内皮细胞E1A激活基因细胞阻遏子的表达随凋亡的增加而增加,E1A激活基因细胞阻遏子过表达的人脐静脉内皮细胞去血清饥饿后凋亡较对照组明显减少。 结论：E1A激活基因细胞阻遏子过表达抑制了去血清诱导的人脐静脉内皮细胞凋亡,机制可能与调控PI3K蛋白表达有关。     

川芎提取物对缺氧条件下体外培养的人脐静脉内皮细胞和大鼠脑缺血组织中血管内皮生长因子表达的影响

BACKGROUND： Vascular endothelial growth factor （VEGF） acts as ＂molecular bridge＂ following ischemic stroke to improve and restore blood supply and reduce infarction volume. Clinical studies have demonstrated the efficacy of Rhizoma Chuanxiong （Chuanxiong） in the treatment of ischemic cerebrovascular diseases. However, whether it promotes endogenous VEGF expression in ischemic stroke remains unknown. OBJECTIVE： To investigate the influence of Rhizoma Chuanxiong on VEGF production in vitro cultured human umbilical vein endothelial cells and on VEGF expression in ischemic cerebral tissues to explore its role in angiogenesis. DESIGN, TIME AND SETTING： In vitro basic comparison of traditional Chinese drug-containing serum pharmacology; in vivo randomized, controlled, animal experiment. This study was performed at the Medical Laboratory of West China Hospital, Sichuan University between December 2002 and April 2004. MATERIALS： Two Chinese rabbits were selected. One was intragastrically perfused with 5.8 g/kg Rhizoma Chuanxiong extract twice per day for three consecutive days to prepare Rhizoma Chuanxiong extract-containing serum. The remaining rabbit was intragastrically perfused with the same volume of normal saline twice per day for three consecutive days. Rhizoma Chuanxiong extract was provided by Beijing Traditional Chinese Medicine Research Institute, predominantly composed of ligustrazine, ligustilide, and ferulic acid. ChemiKineTM human VEGF Kit was purchased from Chemicon, USA; mouse anti-VEGF monoclonal antibody and biotin-goat anti-mouse IgG were purchased from Santa Cruz Biotechnology. Inc., USA. METHODS： （1） In vitro experiment： in vitro cultured human umbilical vein endothelial cells were separately incubated in rabbit serum with 10% Rhizoma Chuanxiong extract, normal medium without rabbit serum, and rabbit serum without Rhizoma Chuanxiong extract （blank control）. In addition, cells from the three groups were incubated under normoxia （5% CO2, 95% air） and hypoxia （1% 02, 5% CO2, 94% N2）, respectively, for 24 hours. （2） In vivo experiment： a total of 4/44 Sprague Dawley rats were selected for the sham-operated group （no occlusion）, and the remaining rats were used to establish a cerebral ischemiaJreperfusion model by suture occlusion. 32 animals with ischemia/reperfusion injury were randomly divided into treatment and model groups, with 16 rats in each group. Both groups were intraperitoneally infused with 0.58 g/kg Rhizoma Chuanxiong extract and normal saline two hours following reperfusion. The sham-operated group was administrated normal saline. Animals were treated with saline or Chuanxiong extracts （0.58 g/kg） twice per day for three consecutive days. MAIN OUTCOME MEASURES： In vitro experiment： VEGF concentration was detected in each group by enzyme-linked immunosorbent assay. In vivo experiment： behavioral alterations of rats were evaluated by neurological function scale; infarct volume was assessed by hematoxylin-eosin staining; VEGF protein expression in the infarct regions was determined by immunohistochemistry. RESULTS： （1） VEGF levels were similar between the three groups under normexic condition （P 〉 0.05）; while hypoxia induced VEGF production （P 〈 0.01 ）. VEGF levels in the drug-containing serum group were particularly higher compared with the other groups （P 〈 0.01）. （2） Compared with normal saline treatment, Rhizoma Chuanxiong extract significantly improved the neurological scale and reduced cerebral infarct volumes （P〈 0.05）. The percent of VEGF-positive cells was significantly greater than the model group （P 〈 0.05）. The sham-operated group exhibited normal neurological function, with no infarct focus. CONCLUSION： Rhizoma Chuanxiong extract-containing rabbit serum effectively promoted cultured VEGF production under hypoxia. Rhizoma Chuanxiong extract upregulated VEGF expression in the infarct region, improved neurological function, and reduced infarct size.     

血管内皮细胞生长因子对人脐静脉间充质干细胞生长增殖的影响

背景：在体外构建组织工程材料的过程中，快速获得足够数量且纯度高的种子细胞极为重要，但目前人脐静脉间充质干细胞原代培养的增殖率仍较低。 目的：观察血管内皮细胞生长因子对人脐静脉间充质干细胞原代生长、增殖的影响。 设计、时间及地点：细胞学体外观察，于2008-03/07在辽宁医学院解剖学实验室完成。 材料：正常健康产妇顺产或剖宫产的新生儿脐带20条，由锦州市凌河区妇幼保健院及辽宁医学院附属第一医院提供。 方法：采用胶原酶消化法分离人脐静脉间充质干细胞，以1×108 L-1的密度接种于24孔培养板，设立2组，实验组加入150 g/L血管内皮细胞生长因子，对照组不加入任何细胞因子。 主要观察指标：观察细胞形态变化，MTT法检测细胞生长曲线，免疫细胞化学法鉴定细胞CD166的表达。 结果：接种后6 h细胞开始贴壁，48 h后细胞完全贴壁生长，出现呈椭圆形、多角形的内皮细胞，以及呈梭形的成纤维样细胞，有的形成漩涡状生长集落；原代培养1周后细胞以梭形为主；传代后24 h细胞基本完成贴壁，48 h细胞开始分裂增殖，5~7 d可见多核的成纤维样细胞贴壁，呈长杆状、三角形、梭形等。与对照组比较，实验组细胞生长状态较好，增殖较快，单位时间内获得的细胞数量明显增加(t=2.235，P < 0.05)，CD166阳性细胞率显著升高(t=1.638，P < 0.01)。 结论：血管内皮细胞生长因子可促进人脐静脉间充质干细胞贴壁，且更有利于间充质干细胞的增殖和纯化。     

Binding of tissue plasminogen activator to human umbilical vein endothelial cells

Binding of purified recombinant human tissue plasminogen activator to cultures of human umbilical vein endothelial cells (HUVEC) was studied in vitro. 125I-tPA was shown to bind to HUVEC in a specific, saturable, and dissociable manner. Scatchard analysis revealed a low affinity binding site with Keq = 4.2 X 10(6) M-1 and 1.2 X 10(7) sites per cell. Binding of tPA was inhibited by L-lysine, e-aminocaproic acid, and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone but not by carbohydrates including mannose, galactose, N-acetyl glucosamine and N-acetyl galactosamine. Neat human plasma abrogates but does not totally inhibit binding of tPA to HUVEC. These results may indicate a role for endothelial cells in the removal of tPA from the circulation in vivo.     

The proliferation of human umbilical vein endothelial cells in serum-free medium

Experimental conditions have been defined to allow human umbilical vein endothelial cells to grow in the complete absence of serum. Endothelial cells maintained in fibronectin-precoated plastic dishes could be grown in medium RPMI-1640 supplemented with transferrin, insulin, human serum albumin (HSA) and epidermal growth factor (EGF) or fibroblast growth factor (FGF). Endothelial cell growth supplement (ECGS) stimulated the proliferation in the presence of EGF or FGF, but its presence is not absolutely required to obtain growth of endothelial cells in serum-free medium. Serum was only required for a short period to allow attachment and spreading of the cells after trypsinization. Endothelial cells grown to confluence in serum-free medium exhibited morphological characteristics comparable to cells cultured in the presence of human serum, secreted normal quantities of factor VIII-related antigen into the culture medium, and synthesize prostacyclin.     

二苯乙烯苷对人脐静脉血管内皮细胞缺氧复氧损伤的影响

背景：大量实验表明，中药何首乌有效活性成分二苯乙烯苷具有降血脂、抗动脉粥样硬化和保护心血管等作用。在许多病理过程中，活性氧可引起细胞脂质过氧化，引起细胞转运功能和酶的性质发生改变，丧失了对细胞离子的调节功能。 目的：观察二苯乙烯苷对人脐静脉血管内皮细胞缺氧/复氧损伤是否具有保护作用。 设计、时间及地点：以血管内皮细胞为观察对象的随机对照实验，于2006-04/10在九江学院医学院分子生物实验中心完成。 材料：人脐静脉血管内皮细胞株。 方法：采用人脐静脉血管内皮细胞建立缺氧复氧损伤模型，干预实验分为8组，每组重复6次。对照组为人脐静脉血管内皮细胞常氧条件下培养；缺氧复氧组为人脐静脉血管内皮细胞缺氧3 h后分别复氧2 h；10，5，2.5 ng/L二苯乙烯苷治疗组分别在缺氧复氧损伤前及缺氧复氧损伤后给予相应剂量的二苯乙烯苷；10，5，2.5 ng/L二苯乙烯苷预处理组分别在缺氧复氧损伤前给予相应剂量的二苯乙烯苷。 主要观察指标：应用四甲基偶氮唑盐比色法测定细胞活力；用UV-1206紫外光分析光度计检测乳酸脱氢酶、总抗氧化能力、丙二醛、超氧化物歧化酶及一氧化氮。 结果：二苯乙烯苷能剂量依赖性的提高缺氧复氧血管内皮细胞的存活率，降低乳酸脱氢酶活性及丙二醛浓度，提高总抗氧化能力、超氧化物歧化酶活性及一氧化氮浓度(P < 0.01)，且治疗组比预处理组作用更明显(P < 0.01)。 结论：二苯乙烯苷对血管内皮细胞缺氧复氧损伤具有明显的保护作用，而且其治疗作用优于预防作用。     

Detection of up-regulated genes in thrombin-stimulated human umbilical vein endothelial cells

INTRODUCTION: Thrombin, a serine protease, plays an important role in such actions as coagulation, cell proliferation and inflammation. It has been sporadically reported that endothelial cells, when stimulated by thrombin via protease-activated receptors (PAR), express various mediators and proteins including cytokines, chemokines, growth factors, and adhesion molecules. However, the pleiotropic effect of thrombin on endothelial cells has not yet been fully elucidated. MATERIALS AND METHODS: We newly searched for the up-regulated genes in the thrombin-stimulated endothelial cells by thorough screening using a microarray chip, printed with 22,575 human genes, followed by verification using real-time PCR (n=3). RESULTS AND CONCLUSIONS: Twelve genes, which were 4.8 times or more up-regulated in a microarray analysis, were selected and further analyzed. In real-time PCR, ICAM-1, IL-8, BIRC3, COL3A1, CXCL3, and CXCL1 were significantly up-regulated in the thrombin-stimulated cells: 16.0-, 8.81-, 5.92-, 3.74-, 1.74-, and 1.66-fold, respectively. VCAM-1, CXCL2, CCL20, CSF2, CD69, and CCL2 were up-regulated in the thrombin-stimulated cells: 12.2-, 2.44-, 1.90-, 1.82-, 1.62-, and 1.06-fold, respectively, without attaining statistical significance. We demonstrated, for the first time, that BIRC3 (anti-apoptotic protein), COL3A1 (matrix protein synthesis), and CXCL3 (chemokine) were up-regulated in the thrombin-stimulated HUVECs.     

Interaction of 3H-defibrotide with cultured human umbilical vein endothelial cells

Defibrotide is a profibrinolytic and antithrombotic drug which seems to modulate endothelial cell function. In this study, a method for radioactive labeling of the drug and its interaction with cultured endothelial cells is proposed. 3H-Acetic anhydride was used to label defibrotide. Endothelial cells obtained by collagenase treatment of human umbilical cord veins were cultured in 24-welled plastic culture dishes. Binding experiments were carried out by incubating cell cultures with media containing various concentrations of labeled defibrotide. Our results showed that labeled defibrotide has a KL value of 4.2 micrograms/ml for endothelial cells. Although the presence of a specific transporter is possible, the high molecular weight of the fraction used suggests that the interaction is binding to a specific receptor.