碘克沙醇对体外血管内皮细胞的影响

目的观察非离子型等渗对比剂碘克沙醇（威视派克）随浓度和时间变化对人血管内皮细胞的活力影响,探讨对比剂毒副作用发生的可能机制。方法人脐静脉血管内皮细胞株置于含不同浓度（4%、10%、20%）非离子型等渗对比剂碘克沙醇培养液中24、48、72 h后,通过噻唑蓝比色法检测细胞增殖活力,用Annexin V/PI双染色法进行细胞凋亡测定,观察不同条件下内皮细胞对对比剂的反应。结果碘克沙醇使血管内皮细胞吸光度下降（P〈0.01）;不同浓度影响不尽相同,而不同作用时间间差异无统计学意义（P〉0.05）。碘克沙醇使血管内皮细胞凋亡率明显增高（P〈0.05）,不同浓度间差异无统计学意义（P〉0.05）。结论体外培养环境下非离子型等渗对比剂碘克沙醇随浓度和时间变化会对内皮细胞产生活力影响,并诱导其凋亡。     

当归挥发油对人脐静脉内皮细胞增殖、凋亡及Ⅲ型胶原合成的影响

目的探讨当归挥发油对人脐静脉内皮细胞增殖、凋亡和胶原合成的影响。方法体外培养人脐静脉内皮细胞，用噻唑蓝比色法检测细胞增殖活性，用流式细胞术分析细胞周期及凋亡，用放射免疫法测定胶原合成。结果低浓度（≤4mg／L）当归挥发油促进细胞增殖（P〈0．05），降低G0/G1期细胞且增加S期细胞（P〈0．05），降低凋亡率（P〈0．05），而高浓度（≥16mg／L）时抑制增殖（P〈0．05），增加G0/G1期细胞且减少S期细胞（P〈0．05），增加凋亡率（P〈0．05）。当归挥发油呈剂量和时问依赖性抑制细胞合成胶原（P〈0．05或0．01）。结论当归挥发油对人脐静脉内皮细胞的增殖呈低浓度刺激高浓度抑制的双向调节作用，但对胶原合成呈抑制效应。     

3TSR体内外诱导内皮细胞凋亡的研究

目的观察血管形成抑制剂3TSR体内外对内皮细胞的影响，并探讨与细胞凋亡蛋白酶．3（Caspase-3）的关系。方法在体外培养条件下比较对照组、不同剂量3TSR（1—3μmol／L）作用48h对人脐静脉血管内皮细胞增殖及凋亡的影响，并用逆转录-聚合酶链反应（RT-PCR）法检测各组Caspase-3 mRNA转录水平。建立裸鼠原位胰腺癌模型，进行随机干预实验，比较对照组（每日0．2ml生理盐水腹腔注射）、3TSR1组（每日1mg／kg体重腹腔注射）、3TSR2组（每日2mg／kg体重腹腔注射）及3TSR3组（每日3mg／kg体重腹腔注射），每组6只，3周后检测胰腺癌原位肿瘤血管内皮细胞凋亡率。结果体外培养时3TSR对人脐静脉内皮细胞有显著增殖抑制及凋亡诱导作用，作用48h后其凋亡率分别为（10．3±3．2）％，（12．4±4．1）％和（20．1±5．4）％，均显著高于对照组（P〈0．05）。3TSR1组、3TSR2组和3TSR3组Caspase-3 mRNA转录水平相对强度分别（0．76±0．11），（0．79±0．21）和（0．89±0．19），均显著高于对照组（P〈0．05），且随浓度增加而增强。体内实验时3TSR能显著诱导胰腺癌血管内皮细胞凋亡，3TSR1组、3TSR2组及3TSR3组凋亡率分别为（7．8±3．0）％，（14．6±4．9）％和（15．9±3．2）％，均显著高于对照组（P〈0．05）。结论3TSR体内外均能诱导内皮细胞的凋亡，且呈一定的浓度依赖性，其作用机制可能与促进Caspase-3基因转录有关。     

复温速率对冷冻保存的同种异体血管结构功能的影响

目的比较不同复温速率对冷冻保存的同种异体血管结构和功能的影响。方法取32段新鲜的兔颈总动脉,按照程序降温至-100℃后置于液氮中保存四周。取出后按不同复温速率,分为A组（100℃/min）、B组（30℃/min）、C组（15℃/min）以及未经冷冻的正常组（每组n=8）,通过光镜和电镜观察血管结构变化,采用DNA原位末端标记（TUNEL）比较各组血管壁中细胞的凋亡率。在器官浴槽中测定不同血管的内皮依赖型舒张功能和非内皮依赖型舒张功能。结果光镜和电镜下观察,A组内皮细胞大片脱落,平滑肌细胞变形,胞浆可见大量空泡,而B和C组内皮细胞和平滑肌细胞保存较好。A组血管壁细胞凋亡率高于B、C组（P〈0.05）。血管舒张功能试验结果示,A组最大内皮依赖型舒张力百分比低于B、C组（P〈0.05）,内皮细胞对乙酰胆碱的敏感性也低于B、C组（P〈0.05）。而A组最大非内皮依赖型舒张力百分比低于B、C组（P〈0.05）,但A组平滑肌细胞敏感性较B、C组和正常组没有明显改变。结论逐步缓慢复温对冷冻保存的同种异体血管的结构和功能有一定的保护作用。     

自噬抑制2-DG诱导内皮细胞凋亡

目的探讨2-脱氧.D-葡萄糖(2-DG)诱导人脐静脉血管内皮细胞发生凋亡与自噬及两者之间的关系。方法传代培养人脐静脉血管内皮细胞,在常氧实验条件下,细胞被分为对照组,不同浓度的2-DG组、2-DG联合甘露糖组、阳性对照组(衣霉素组),利用MTS比色法检测2-DG对人脐静脉血管内皮细胞增殖活性的影响;利用Western blot免疫印记技术,检测细胞内质网应激相关蛋白-葡萄糖调节蛋白78(GRP78)的表达水平,以反映处理后的细胞内质网应激的水平变化;以Annexin V-PI流式细胞术检测人脐静脉血管内皮细胞凋亡。为了检测2.DG对细胞自噬的影响,引入自噬抑制剂3-MA,采用Western blot免疫印记技术,检测自噬相关蛋白Beclin 1和Atg 5的表达水平,以反映处理后的细胞自噬水平变化。结果 2-DG组细胞增殖活力明显降低,与对照组相比具有统计学意义,且该抑制作用呈剂量依赖性;2.DG联合甘露糖组增殖活力有所增加,与单独2-DG组相比具有统计学意义;2-DG组凋亡率明显增加,与对照组相比具有统计学意义,2.DG联合甘露糖组细胞凋亡减少,与单独2.DG组相比具有统计学意义;2-DG组GRP78蛋白水平增加,与对照组相比具有统计学意义;加入甘露糖后,GRP78蛋白水平减少,与单独2-DG组相比具有统计学意义;2-DG组Beclin1和Atg5蛋白表达均有所增加,与对照组相比具有统计学意义;3-MA预处理细胞抑制自噬后,2-DG诱导的细胞凋亡增多,Beclin1和Atg5蛋白表达也有所减少,与2-DG组相比具有统计学意义。结论 2-DG显著抑制人脐静脉血管内皮细胞增殖,诱导人脐静脉血管内皮细胞凋亡及自噬;内质网应激可能是介导2-DG诱导细胞凋亡的相关作用机制;2-DG诱导的细胞自噬则能抑制细胞凋亡。     

H2O2、LPS 和 TNF-α诱导人类脐静脉内皮细胞损伤的实验研究

目的探讨人类脐静脉内皮细胞损伤模型建立方法,为体外研究血管内皮细胞提供实验基础。方法分离培养人类脐静脉内皮细胞,分别采用不同浓度的过氧化氢（H2O2）、脂多糖（LPS）、肿瘤坏死因子（TNF）‐α刺激细胞,孵育不同时间后,采用四甲基偶氮唑盐（MTT）法检测细胞活力（OD值）。结果各浓度H2O2损伤组较对照组OD值显著降低（P＜0．01）,不同浓度H2O2损伤组间OD值无统计学差异（P＞0．05）。0．1μg／mLLPS损伤组与对照组OD值无统计学差异（P＞0．05）;其余各浓度LPS损伤组较对照组OD值显著降低（P＜0．05）,且LPS浓度在一定范围内,OD值随LPS浓度的增加及作用时间的延长而降低,具有一定的浓度与时间依赖性。各浓度TNF‐α损伤组较对照组OD值显著降低（P＜0．01）,且TNF‐α浓度在一定范围内,OD值随TNF‐α浓度的增加及作用时间的延长而降低,具有一定的浓度与时间依赖性。结论H2O2、LPS和TNF‐α能体外损伤人类脐静脉内皮细胞,成功建立人类脐静脉内皮细胞损伤模型,且在一定浓度范围内各损伤因子对人类脐静脉内皮细胞损伤程度呈浓度和时间依赖性。     

人脐静脉内皮细胞分离与冻存技术及Gore-Tex人工血管内皮化

目的体外分离人脐静脉内皮细胞，进行冷冻保存，并采用冻存脐静脉内皮细胞，复融后体外扩增培养，种植于Gore-Tex表面，进行人工血管内皮化。方法脐静脉内灌注消化液分离内皮细胞，所获内皮细胞体外培养，经免疫荧光染色及扫描电镜检查，鉴定所获内皮细胞及其纯度；采用梯度降温法，冻存内皮细胞，经复苏后，进行形态学检查，以台酚蓝试验、四氮唑盐（MTT）试验、流式细胞术细胞凋亡检测等方法鉴定细胞生物特性；冻存脐静脉内皮细胞体外培养扩增后，种植于Gore-Tex材料上，并行扫描电镜观察。结果血管内灌注消化液法可获取高纯度的内皮细胞；与新鲜细胞相比，复苏的内皮细胞活力保持在95％以上；复苏后的内皮细胞HE染色及生长曲线与新鲜细胞差异无统计学意义。冻存内皮细胞的凋亡率较新鲜内皮细胞高，但无统计学差异。冻存内皮细胞成功种植于Gore-Tex材料上．细胞生长良好，覆盖于大部分Gore-Tex表面。结论冻存内皮细胞作为种子细胞对人工血管内皮化具有可行性。脐静脉灌注酶消化法可获取足够数量及纯度的内皮细胞。冻存的内皮细胞复苏后无明显形态学改变，并保持较高的活力及体外增殖能力，可作为种子细胞来源。     

复方消可宁颗粒剂对高糖诱导的内皮细胞氧化应激的保护作用

目的：观察消可宁颗粒剂对高糖培养的人脐静脉血管内皮细胞（ECV-304）黄嘌呤氧化酶（XOD）、超氧化物岐化酶（SOD）及超氧阴离子（O2^-.）的影响。方法：体外培养ECV-304细胞,分空白对照组（Ⅰ）、高糖对照组（Ⅱ）和5个消可宁浓度递增组（Ⅲ～Ⅶ）。药物干预后,检测XOD、O2^-.和SOD的吸光度,计算出活力。结果：各消可宁组XOD含量较高糖对照组显著下降,SOD活力明显增加及O2^-.生成减少,两组比较有统计学差异（P〈0.05）。结论：消可宁可能通过降低内皮细胞XOD、减少O2^-.生成,增加SOD活力,从而抗御氧化应激,保护血管内皮。     

2-脱氧-D-葡萄糖对人脐静脉内皮细胞的作用

目的观察2-脱氧-D-葡萄糖对人脐静脉内皮细胞增殖、迁移、管腔形成及细胞凋亡的影响,试图寻找治疗血管瘤的新药。方法用四甲基偶氮唑盐比色法、倒置显微镜下形态学观察、体外划痕实验的方法,观察2-脱氧-D-葡萄糖对人脐静脉内皮细增殖、迁移的作用;用成管法,检测2-DG对血管形成的影响;用流式细胞仪检测2-DG对血管内皮的凋亡影响、结果2-DG作用于人脐静脉内皮细胞后,对其增殖,迁移和成管能力有明显抑制作用,大大地增加细胞的凋亡率,且有显著剂量和时间依赖性．结论2-DG对HUVEC增殖、迁移和成管有显著的抑制作用,且能促使细胞凋亡。     

黄芪多糖对人脐静脉内皮细胞的增殖及表达 VEGF 的影响

目的：研究黄芪多糖（astragaluspolysacharin,APS）对人脐静脉内皮细胞（human umbilical vein endothelial cells,HUVEC）周期及血管内皮细胞生长因子（vascular endothelial growth factor,VEGF）表达的影响。方法：用不同浓度黄芪多糖对 HUVEC 进行干预培养,流式细胞仪检测细胞周期以及细胞凋亡;荧光倒置显微镜检测细胞表达 VEGF 的免疫荧光。结果：MTT 法表明,APS 在一定的范围内（0.1~100 μg/mL）能以剂量依赖方式促进 HUVEC 细胞周期从 G0/G1 期向 G2/M 期和 S 期转变,流式细胞凋亡检测显示 APS 并未增加 HUVEC 凋亡率。细胞免疫荧光染色实验结果表明,APS 促进 VEGF 表达。结论：APS 在一定的浓度范围内（0.1~100 μg/mL）促进 HUVEC 细胞分裂增殖。APS 还能上调 HUVEC 细胞 VEGF 的表达水平,为进一步血管化提供有效的促血管化因子,为治疗缺血性疾病提供新思路。     

NF-κB信号通路对高糖诱导的人脐静脉内皮细胞凋亡的作用

目的 研究高糖尤其是波动性高糖对人脐静脉内皮细胞（HUVEC）凋亡的影响,以及NF-κB信号通路在高糖诱导HUVEC凋亡中的作用。 方法 构建针对NF-κBp65 mRNA序列1566位点的重组RNAi腺病毒表达载体,并利用RNAi腺病毒抑制HUVEC p65表达。应用流式细胞术及脱氧核糖核苷酸末端转移酶介导的缺口末端标记法（TUNEL）研究NF-κB信号通路在高糖诱导HUVEC凋亡的作用。 结果 高糖（20.5 mmol/L或30.5 mmol/L）可以促进HUVEC凋亡。NF-κBp65 特异腺病毒感染HUVEC后,可以明显抑制高糖刺激的NF-κBp65核蛋白转录,使核内p65蛋白表达处于基础水平。TUNEL结果示高糖作用后5 d,高糖组细胞凋亡率显著高于正常葡萄糖组（25.81％±1.77％比8.20％±0.63％,P < 0.05）,Ad-DEST＋高糖组（26.10％±0.98％）与单独高糖组的细胞凋亡率差异无统计学意义（P > 0.05）。Ad-1566＋高糖组的细胞凋亡率（11.49％±0.92％）比Ad-DEST＋高糖组显著下降（P < 0.01）。TUNEL法及流式细胞术检测结果均显示NF-κBp65 特异腺病毒可以降低高糖诱导的HUVEC凋亡。结论 高糖可以促进HUVEC凋亡。腺病毒感染HUVEC可以明显抑制高糖刺激的NF-κBp65核转录,从而保护高糖作用的HUVEC凋亡。     

Positive effect of treatment with synthetic steroid hormone tibolon on intimal hyperplasia and restenosis after experimental endothelial injury of rabbit carotid artery

BACKGROUND: Arterial intimal hyperplasia and following restenosis may be inhibited by estrogens. We investigated the effect of a synthetic steroid hormone, Tibolon: (a) on intima hyperplasia and restenosis in vivo, and (b) on production of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), endothelial cell proliferation and apoptosis in vitro. METHODS: Influence of Tibolon treatment (0.1 mg/kg body weight, during 3 days before and 3 weeks after the operation as a drinking solution once daily) on neointimal formation (measured by morphometry) and arterial wall damage (by qualitative histology) were investigated in vivo using an animal model of balloon injury of carotid artery. In human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMEC-1), the effect of Tibolon (0.1 microg/ml) on eNOS and VEGF was assessed by ELISA. Cell proliferation was induced by VEGF(165) and measured by BrdU incorporation assay, cell apoptosis was detected colorimetrically measuring DNA fragmentation. RESULTS: Balloon injury resulted in neointima formation and prominent damage of the carotid artery wall. Treatment with Tibolon increased luminal area, decreased intimal area and intima to media ratio, and promoted better reparation of damaged vessel wall. In vitro, Tibolon treatment did not influence the expression of eNOS protein in HUVEC as well as cell proliferation rate but reduced apoptosis of endothelial cells by about 40%. Additionally, this treatment suppressed basal and IL-1beta-stimulated synthesis of VEGF in HMEC-1. CONCLUSIONS: Tibolon treatment suppressed neointimal formation and promoted better reparation of damaged vessel wall in carotid artery after balloon injury. This positive effect seems to be associated with improved endothelial cell survival resulting possibly in increased NO production. It might be also related to the decrease of VEGF generation.     

Effects of p-cresol on the proliferation and cell cycle of human umbilical vein endothelial cells

Objective To investigate the effects of p-cresol on human umbilical vein endothelial cells. Methods The effects of p-cresol on endothelial cell growth, cell cycle, cell morphological change and p21 protein were detected by the CCK-8 assay, flow cytometry assay, inverted microscope and Western blotting. Results P-cresol could inhibit the growth of human umbilical vein endothelial cells in dose- and time-dependent manners (all P＜0.05). The human umbilical vein endothelial cells treated with p-cresol became elongated processes, cloudy cytoplasm, and irregular shapes. The p-cresol stopped human umbilical vein endothelial cells at cell cycle G1 and had no effect on cell apoptosis. The p-cresol could increase protein expression of p21 in a dose dependent manner (P＜0.05). Conclusion P-cresol can increase protein expression of p21, induce cell cycle arrest at G1 stage and inhibit the proliferation of human umbilical vein endothelial cells.     

高浓度二氧化碳预处理对人脐静脉内皮细胞缺氧复氧损伤的影响

目的 探讨高浓度二氧化碳(CO2)预处理对人脐静脉内皮细胞缺氧复氧损伤的影响.方法 人脐静脉内皮细胞接种于细胞培养板,随机分为6组,每组16孔,对照组(C组)常规培养;缺氧复氧组(MR组)缺氧4 h、复氧24 h;缺氧预处理组(APC组)缺氧10 min、复氧10 min,重复2次后缺氧4 h、复氧24 h;HCA.组、HCA2组和HCA3组分别于50%N-20%02-30%CO2培养箱中行30%CO2预处理10、30、60 min后常规培养10、20、30 min,缺氧4 h、复氧24 h.于复氧24 h时采用MTY法测定人脐静脉内皮细胞活力,采用免疫细胞化学法测定细胞间粘附分子-1(ICAM-1)表达水平.结果 与C组比较,MR组、APC组、HCA1～3组人脐静脉内皮细胞活力降低,ICAM-1表达上调(P＜0.05);与A/R组比较,APC组和HCA2组人脐静脉内皮细胞活力升高,APC组及HCA1,2组ICAM-1表达下调(P＜0.05).结论 高浓度CO2预处理可减轻人脐静脉内皮细胞缺氧复氧损伤.     

Human umbilical vein endothelial cells accelerate oxalate-induced apoptosis of human renal proximal tubule epithelial cells in co-culture system which is prevented by pyrrolidine dithiocarbamate

Oxalate is the most common component of kidney stones and elevated urinary levels induce renal tubular cell toxicity and death which is essential for crystal attachment. Endothelial cells, in some studies have been shown to regulate certain functions of renal proximal tubule cells. The aim of this study was to evaluate the effect of endothelial cells on tubular cell apoptosis in a co-culture system mimicking the in vivo renal physiological settings. The human umbilical vein endothelial cells (HUVEC) and human renal proximal tubule epithelial cells (RPTEC) were exposed to increasing concentrations (0-1.0?mM) of oxalate with or without 10?μM PDTC pretreatment for 24?h. In HUVEC, RPTEC and HUVEC-RPTEC co-cultures, the cell viability was measured using the WST-1 assay and cell death with the TUNEL analysis using the flow cytometry. The treatment of RPTECs with oxalate lead to 8.9-26.2% cell death which was reduced to 0-1.6% with the PDTC pretreatment. The death rate of RPTECs was significantly increased by 15-19% at different oxalate concentrations when co-cultured with HUVECs. In contrast, cell viability was not substantially altered in PDTC pretreated RPTECs that were co-cultured with HUVECs. Apoptosis was the way of cell death as similar rate of apoptosis was observed in cell culture systems. Although cell viability of RPTECs was further reduced when co-cultured with HUVECs, it was restored with the pretreatment of PDTC. This is the first study focusing on the role of endothelial cells on RPTEC apoptosis following hyperoxaluria.     

Cisatracurium, but not mivacurium, induces apoptosis in human umbilical vein endothelial cells in vitro

BACKGROUND AND OBJECTIVE: Cisatracurium is an intermediate acting, non-depolarizing neuromuscular blocking agent. Previous reports have indicated a growth-inhibitory effect of the isoforms cisatracurium and atracurium on two human cell lines in vitro. These effects were ascribed to oxidative stress elicited by acrylate esters formed during cisatracurium breakdown. Oxidative stress is a potent precipitator of apoptosis. Therefore, the aim of the present study was to investigate whether the growth-inhibitory effects of cisatracurium could be explained by initiation of apoptosis. METHODS: Human umbilical vein endothelial cells were incubated with cisatracurium at concentrations of 0.96, 3.2, 9.6, 32 and 96 micromol for 24 h. DNA fragmentation was measured using the Cell Death Detection ELISA Plus assay (Roche Diagnostics, Mannheim, Germany). RESULTS: There was a dose dependency of cisatracurium with respect to the rate of apoptosis in human umbilical vein endothelial cells. Programmed cell death could be demonstrated at concentrations encountered in human plasma after single-bolus injections of cisatracurium. Apoptosis was attenuated by the concomitant administration of glutathione. CONCLUSIONS: These findings strongly support the hypothesis that acrylate esters, breakdown products of cisatracurium, induce oxidative stress and, subsequently, apoptosis.     

The effect of trophic factor supplementation on cold ischemia-induced early apoptotic changes

We have previously shown that trophic factor supplementation (TFS) of University of Wisconsin (UW) solution enhanced kidney viability after cold storage. Here, we use an in vitro model to study the effect of TFS on early apoptotic changes after cold ischemic storage. Mitochondrial membrane potential was determined by fluorescence intensity in primary canine kidney tubule cells, Madin-Darby canine kidney cells, and human umbilical vein endothelial cells. In addition, caspase 3 enzyme activity assay and immunofluorescence staining were performed to evaluate apoptosis. There was a 15% increase in mitochondrial membrane potential in human umbilical vein endothelial cells stored in trophic factor supplemented University of Wisconsin solution after four-hour rewarming (P<0.05). TFS suppressed caspase 3 enzyme activity and activation in human umbilical vein endothelial cells. We confirmed that the presence of TFS in UW solution has a beneficial effect by protecting mitochondrial function and reducing early apoptotic changes in vascular endothelial cells.     

The influence of atracurium, cisatracurium, and mivacurium on the proliferation of two human cell lines in vitro

We tested the influence of atracurium and cisatracurium (final concentrations: 0, 0.96, 3.2, 9.6, 32, and 96 microM) on proliferation of human cells (hepatoma HepG2 cells and human umbilical vein endothelial cells) in vitro. In additional experiments, glutathione, N-acetylcysteine, or carboxyl esterase was added before the addition of either relaxant. The number of cells counted after 72 h of incubation was expressed as a percentage of the mean cell number in wells incubated without additives. Atracurium and cisatracurium progressively decreased cell proliferation in a concentration-dependent pattern. With human umbilical vein endothelial cells, atracurium or cisatracurium (3.2 microM) decreased the cell count to 67.7 % (SD, 14.8%) and 50% (SD, 8.6%), respectively. Cell proliferation was not inhibited by mivacurium. The results were similar to those with HepG2 cells. Glutathione, N-acetylcysteine, and carboxyl esterase partially reversed the effects of atracurium and cisatracurium. When incubated in a buffer with glutathione, atracurium decreased the number of glutathione-sulfhydryl groups. The findings that atracurium and cisatracurium inhibit proliferation of human cell lines in vitro, but that mivacurium does not, and that this effect is alleviated by glutathione and N-acetylcysteine, as well as by the carboxyl esterase, indicate that the inhibition may be caused by the reactive acrylate metabolites.     

Comparison of Angiogenic Potential of Human Microvascular Endothelial Cells and Human Umbilical Vein Endothelial Cells

Summary BACKGROUND: Endothelial cells cultured in vitro are commonly used as a model for testing the effects of therapeutic or detrimental agents on endothelium. Cells originating from different vascular beds display, however, a heterogeneity of function and phenotype. Here we compared the production of angiogenic growth factors and the sensitivity to exogenous growth factor stimulation of two popular endothelial cell types. METHODS: Experiments were performed on human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells (HMEC-1) incubated in optimal conditions for 24–48 h. RESULTS: The profile of the spontaneously produced growth factors differed significantly between the two different cell lines tested. HUVEC did not produce detectable amounts of VEGF, whereas HMEC-1 released 24.9 pg/ml and this amount was significantly increased in response to IL-1. Instead, HUVEC produced high concentrations of soluble form of VEGF receptor-1 (VEGF-R1), whereas the release of VEGF-R1 from HMEC-1 was 10-fold lower. Small amounts of bFGF were found in media from both cell types, but higher levels were detected in HMEC-1 cultures. In contrast, the secretion of interleukin-8 (IL-8) and matrix metalloproteinase-1 (MMP-1) were 30- to 40-fold higher in HUVEC than in HMEC-1. The cell types differed also in their sensitivity to exogenous growth factors. The basal proliferation of HUVEC was very low but could be effectively stimulated by supplementation with VEGF or bFGF. HMEC-1 proliferated spontaneously and their proliferation rate was not further augmented by growth factors. Similarly, the spontaneous outgrowth of capillaries was negligible in HUVEC but well pronounced in HMEC-1. CONCLUSIONS: Production of angiogenic agents and sensitivity to exogenous growth factors is cell-type dependent. HUVEC, which do not release VEGF, can be easily stimulated with exogenous factors, whereas HMEC-1, which are able to produce VEGF, do not respond well to the additional stimulation. Our study demonstrates that conclusions resulting from in vitro experiments performed on only one type of endothelial cells can be misleading.