Prostanoid release of cultured liver sinusoidal endothelial cells in response to endotoxin and tumor necrosis factor : Comparison with umbilical vein endothelial cells

Vascular endothelial cells release prostanoids, especially prostacyclin, when properly stimulated. In addition to short acting stimuli like thrombin and histamine an increased prostanoid release occurs in the presence of endotoxin, interleukin 1 or tumor necrosis factor (TNF). The response of sinusoidal endothelial liver cells to such stimuli - probably important in hepatic inflammatory disease - is unknown. Sinusoidal endothelial liver cells from the guinea pig were isolated by centrifugal elutriation and investigated as confluent monolayers. Their prostanoid release in response to endotoxin and human recombinant TNF was determined by radioimmunoassays and compared to that obtained with cultured human umbilical vein endothelial cells. A pronounced time- and dose-dependent release of prostanoids was found with both cell types in response to endotoxin. In contrast to umbilical vein cells, liver endothelial cells produced not only large amounts of 6-keto-PGF1 alpha and some PGE2 but also thromboxane B2. Only umbilical vein endothelial cells responded to TNF with an increased 6-keto-PGF1 alpha release, emphasising the metabolic differences between both cell types.     

Evidence against the hypothesis that endothelial endothelin B receptor expression is regulated by relaxin and pregnancy

The endothelial endothelin B (ET(B)) receptor subtype is critical for renal vasodilation induced by relaxin in nonpregnant rats and during pregnancy (the latter via endogenous circulating relaxin). Here we tested whether expression of vascular ET(B) receptor protein is regulated by relaxin. Small renal arteries were harvested from virgin and midterm pregnant rats as well as nonpregnant rats that were administered recombinant human relaxin (rhRLX) at 4 mug/h or vehicle for 5 d or 4-6 h. Small renal arteries dissected from additional virgin rats were incubated in vitro with rhRLX or vehicle for 3 h at 37 C. ET(B) expression was also evaluated in cultured human endothelial cells: aortic, coronary, umbilical vein, and dermal microvascular endothelial cells. Cells were incubated for 4, 8, or 24 h with rhRLX (5, 1, or 0.1 ng/ml) or vehicle. ET(B) protein expression in arteries and cells was evaluated by Western analysis. No regulation of ET(B) expression was observed in small renal arteries in any of the experimental protocols, nor was there an increase in the vasorelaxation response to ET-3 in small renal arteries incubated in vitro with rhRLX. rhRLX only sporadically altered ET(B) expression in human coronary artery endothelial cells and human umbilical vein endothelial cells at certain time points or doses, and no regulation was observed in human aortic endothelial cells or human dermal microvascular endothelial cells. These results suggest that regulation of ET(B) receptor protein has little or no role in relaxin stimulation of the endothelial ET(B)/nitric oxide vasodilatory pathway.     

Endothelin-1 release from cultured endothelial cells induced by sera from patients with systemic lupus erythematosus.

OBJECTIVES--To clarify the pathophysiological role of endothelin-1 (ET-1) in the vascular injury associated with systemic lupus erythematosus (SLE) by investigating the effect of sera from patients with SLE on ET-1 release from cultured human umbilical vein endothelial cells. METHODS--Confluent monolayers of cultured human umbilical vein endothelial cells were incubated with serum samples (diluted 1:10) from 25 patients with SLE and 16 normal controls for two hours at 37 degrees C and ET-1 concentration in the culture supernatant was measured by enzyme immunoassay. RESULTS--The mean release of ET-1 from endothelial cells in the presence of serum from SLE patients was greater than in the presence of serum from normal controls (p < 0.005). ET-1 release from endothelial cells significantly correlated with the titre of IgM anti-endothelial cell antibodies (IgM-AECA) and immune complex concentration in sera from SLE patients (p < 0.05 and p < 0.01, respectively). After gel chromatography of the serum from an SLE patient, those fractions containing IgM-AECA or immune complex were shown to stimulate ET-1 release from endothelial cells. Heat aggregated IgG also stimulated ET-1 release from endothelial cells in a concentration dependent manner. CONCLUSIONS--IgM-AECA and immune complexes may stimulate ET-1 release from endothelial cells and ET-1 may play an important role in the initiation and development of vascular injury, such as pulmonary hypertension and lupus nephritis, in SLE.     

17β-雌二醇对ox-LDL诱导内皮细胞一氧化氮生成的影响

目的 观察17β-雌二醇和氧化低密度脂蛋白(ox-LDL)对人脐静脉内皮细胞一氧化氮(NO)的影响。方法用一氧化氮试剂盒测定不同浓度ox-LDL(50-200μg/L)和17β-雌二醇(0.1nmol/L-10nmol/L)作用于内皮细胞NO产量。结果ox-LDL对培养内皮细胞NO产生有明显抑制作用(P<0.01),雌激素(E2)可促进培养内皮细胞NO的生成(P<0.01),明显减弱ox-LDL对内皮细胞产生NO的抑制作用,与ox-LDL组相比,E2(0.5nmol/L)+ox-LDL组内皮细胞NO含量增加(P<0.01)。结论ox-LDL明显抑制内皮细胞NO的合成,雌激素则有明显的保护作用。     

低分子肝素对血管内皮细胞舒缩功能的影响

目的 :本实验旨在探索低分子肝素是否具有影响内皮依赖性的血管舒缩功能的作用。方法 :人脐静脉内皮细胞株 ECV30 4接种于 6孔板 ,分两组 :低分子肝素组和对照组。低分子肝素组分 4种浓度 :0 .72 ,2 ,5 ,8U /ml。常氧条件下培养 2 4 h后取各组上清液 ,以比色法测定一氧化氮 （NO ）、丙二醛 （MDA ）的含量 ,放免法测定内皮素 （ET）的含量。结果 :常氧条件下 0 .72～ 5 U /ml的低分子肝素促进内皮分泌 NO,而 8U /m l的低分子肝素抑制 NO的分泌 ,但 0 .72～ 8U /ml的低分子肝素始终抑制 ET、MDA生成。结论 :低分子肝素可作用于内皮细胞影响其分泌NO、ET的能力 ,并减少 MDA生成 ,避免氧自由基损伤内皮 ,保护内皮细胞。     

Platelet-derived growth factor does not stimulate prostacyclin synthesis by cultured endothelial cells

We examined the effect of highly purified platelet-derived growth factor (PDGF) on prostacyclin (PGI2) release by cultured human umbilical vein and bovine aortic endothelial cells. PDGF tested at concentrations equal to or exceeding those observed in serum did not increase endothelial cell PGI2 synthesis as measured by radioimmunoassay of its metabolite, 6-keto-PGF1 alpha. In contrast, cells incubated with 20% human whole blood serum (WBS) demonstrated significantly increased PGI2 production (fivefold stimulation). Addition of anti-PDGF antibody to the 20% WBS did not attenuate the increased synthesis of PGI2. Incubation with 20% plasma-derived serum (PDS) that was deficient in PDGF produced stimulation of PGI2 release similar to 20% WBS. These results demonstrate that PDGF does not cause increased PGI2 synthesis in cultured human endothelial cells of human or bovine origin, and further suggest that the stimulation observed with serum is not due to a platelet-release product.     

磷酸化p38介导低切应力诱导的血管内皮细胞Bmi-1表达

目的探讨低切应力(LSS)对人脐静脉内皮细胞(HUVEC)中Bmi-1表达的影响及其可能的机制。方法原代培养HUVEC,免疫荧光检测Bmi-1在细胞中的定位;运用平行平板流动腔系统,给HUVEC加载0.5 Pa低切应力0.5 h、1 h、2 h和4 h,以无切应力加载为对照组,用实时定量RT-PCR检测Bmi-1 mRNA表达,用Western blot检测Bmi-1蛋白表达,利用p38特异性抑制剂SB2219探讨信号转导途径。结果免疫荧光观察发现Bmi-1主要分布在HUVEC胞核中;HUVEC在LSS作用0.5 h后Bmi-1表达即明显增强,随着作用时间延长(1 h、2 h、4 h),Bmi-1mRNA及蛋白表达逐渐降低;切应力能显著激活磷酸化p38表达;SB2219可以明显抑制Bmi-1表达。结论 LSS可诱导HUVEC中Bmi-1表达,其表达量与刺激时间长短密切相关,这种作用可能通过p38信号调节。     

阿托伐他汀通过过氧化体增殖物激活型受体γ促进一氧化氮生成抑制炎性因子产生

目的 观察阿托伐他汀是否能通过激活人脐静脉内皮细胞的过氧化体增殖物激活型受体γ从而改善血管内皮功能.方法 将体外培养的人脐静脉内皮细胞的实验分为两部分,实验一分组:①对照组;②脂多糖组(1.0 mg/L);③阿托伐他汀1.0 mmol/L组;④脂多糖+阿托伐他汀1.0 mmol/L组;⑤脂多糖+阿托伐他汀5.0mmol/L组,经孵育24 h后,收集细胞和培养上清液,用RT-PCB方法测定不同浓度阿托伐他汀对人脐静脉内皮细胞的过氧化体增殖物激活型受体γ表达的影响,并用硝酸还原酶法测定不同浓度阿托伐他汀干预对脂多糖诱导后细胞培养上清液中的一氧化氮生成的影响,ELISA方法测定细胞培养上清液中人可溶性细胞间黏附分子含量的影响.实验二分组:①对照组;②阿托伐他汀5.0 mmol/L组;③0.2 mmol/L GW9662组;④脂多糖+阿托伐他汀5.0mmol/L组;⑤GW9662+脂多糖+阿托伐他汀5.0 mmol/L组,观察过氧化体增殖物激活型受体γ特异性阻断剂GW9662对阿托伐他汀与脂多糖共同作用后人脐静脉内皮细胞的过氧化体增殖物激活型受体γ表达及培养上清液中一氧化氮、人可溶性细胞问黏附分子1含量变化的影响.结果 不同浓度阿托伐他汀可上调人脐静脉内皮细胞的过氧化体增殖物激活型受体γ表达,且随着药物浓度的增加其上调受体表达的作用增强.不同浓度阿托伐他汀可干预脂多糖诱导的人脐静脉内皮细胞液中一氧化氮生成减少及人可溶性细胞间黏附分子1含量的增加,且随着药物浓度的增加上述作用增强.过氧化体增殖物激活型受体γ特异性阻断剂GW9662可部分阻断阿托伐他汀上述作用.结论 阿托伐他汀可能部分通过激活人脐静脉内皮细胞的过氧体增殖物激活型受体γ受体,促进一氧化氮生成,抑制炎性因子的产生,改善血管内皮功能.     

血小板衍生生长因子—BB对血管内皮细胞、平滑肌细胞及成纤维细胞增殖的影响

目的 观察血小板衍生生长因子—BB对培养的人血管内皮细胞、兔平滑肌细胞和人成纤维细胞增殖的影响。方法 采用培养的人脐静脉血管内皮细胞、兔动脉血管平滑肌细胞和人血管成纤维细胞，应用^3H—TdR掺入方法，观察血小板衍生生长因子—BB对三种细胞DNA合成的影响。结果 血小板衍生生长因子—BB可促进处于静止状态的三种细胞DNA的合成，并呈现出明显的浓度依赖关系，在30ng／ml的浓度时成纤维细胞DNA的合成达到高峰，在40ng／ml的浓度时内皮细胞、平滑肌细胞DNA的合成达到高峰。成纤维细胞、平滑肌细胞分别在PDCF-BB作用24h和36h年到DNA合成的高峰，内皮细胞在48h时DNA合成量最高。结论 血小板衍生生长因子—BB可明显促进培养的人脐静脉血管内皮细胞、兔动脉血管平滑肌细胞和人血管成纤维细胞的增殖。     

An in vitro model for the study of acute release of von Willebrand factor from human endothelial cells

An in vitro model is described which utilizes human umbilical vein endothelial cells cultured on plastic microcarrier spheres and perfused with serum-free medium. This model was used to study the acute release of von Willebrand factor following stimulation of the cells with putative agonists. Thrombin, plasmin and interleukin-1 were found to release von Willebrand factor. Adrenaline and bradykinin also stimulated release but only at high dosage. 1-desamino-8-D-arginine vasopressin (DDAVP) was inactive.     

ACE2基因表达增加对人脐静脉内皮细胞增殖、凋亡的影响

目的探索在AngII干预下ACE2基因表达增加对人血管内皮细胞增殖、凋亡的影响。方法原代培养人脐静脉血管内皮细胞。用构建、包装好的慢病毒重组ACE2基因表达载体（Lentiviral—ACE2）以感染复数为10（MOI=10）感染人脐静脉内皮细胞（HUVEC）。感染72h后,以AnglI（终浓度为10。mol／L）干预细胞,倒置相差显微镜观察各组HUVEC的形态学变化,AlamarBlue试剂检测各组HUVEC增殖功能,TUNEL细胞凋亡检测试剂盒检测各组HUVEC的凋亡。结果AngⅡ组与AngII＋Lentiviral—GFP组细胞生长状态差,生长缓慢,形态不规则并且有不同程度脱壁悬浮的细胞;而正常细胞对照组与AngII＋Lentiviral—ACE2组细胞生长状态良好,圆形、卵圆形,饱满,形态正常呈“铺路石”样生长,紧密贴壁,悬浮细胞少。AngII组较正常细胞对照组、Ang1I＋Lentiviral—ACE2组AlamarBlue被还原率明显降低（P〈O．05）。Ang11组的凋亡指数为（0．1165±0．0181）,与正常细胞对照组凋亡指数（0．0373±0．0113）和AngⅡ＋Lentiviral—ACE2组凋亡指数（0．0540±0．0061）相比差异有统计学意义（P〈0．05）。AngII组与AngⅡ＋Lentiviral—GFP相比、正常细胞对照组与AngII＋Lentiviral—ACE2组相比,AlamarBlue被还原率和凋亡指数差异无统计学意义。结论AngⅡ具有促进人脐静脉内皮细胞增殖能力下降和凋亡增加的作用。ACE2表达增~IIII抑制AngⅡ诱导的人脐静脉内皮细朐增殖活件降低和凋亡增加．对人脐静脉内皮细胞具有保护作用。     

An antioxidant role for calcium antagonists in the prevention of adrenaline mediated myocardial and endothelial damage.

OBJECTIVE--To investigate the mechanism of calcium antagonist mediated cytoprotection against the damaging effects of adrenaline in vivo on cardiac myocytes and human endothelial cells from the umbilical vein. METHODS--Human endothelial cells cultured from the umbilical vein and isolated rat cardiac myocytes were treated with plasma from rats given adrenaline 30 minutes previously with pretreatment with calcium antagonists and without. The effect on indices of cell damage that suggest oxidation stress was determined. RESULTS--Pretreatment of rats with calcium antagonists before adrenaline administration largely inhibited the cytotoxic effects of their plasma on the two target cells used. Plasma taken from animals not pretreated with calcium antagonists caused release of oxidised glutathione from cells, a fall in intra-cellular reduced glutathione concentration, a fall in ATP production, and release of angiotensin converting enzyme from the endothelial cells. CONCLUSION--Calcium antagonists protect against the cardiotoxic effects of catecholamine by preventing the generation of plasma borne cytotoxic compounds, which are probably free radicals.     

An antioxidant role for calcium antagonists in the prevention of adrenaline mediated myocardial and endothelial damage

OBJECTIVE--To investigate the mechanism of calcium antagonist mediated cytoprotection against the damaging effects of adrenaline in vivo on cardiac myocytes and human endothelial cells from the umbilical vein. METHODS--Human endothelial cells cultured from the umbilical vein and isolated rat cardiac myocytes were treated with plasma from rats given adrenaline 30 minutes previously with pretreatment with calcium antagonists and without. The effect on indices of cell damage that suggest oxidation stress was determined. RESULTS--Pretreatment of rats with calcium antagonists before adrenaline administration largely inhibited the cytotoxic effects of their plasma on the two target cells used. Plasma taken from animals not pretreated with calcium antagonists caused release of oxidised glutathione from cells, a fall in intra-cellular reduced glutathione concentration, a fall in ATP production, and release of angiotensin converting enzyme from the endothelial cells. CONCLUSION--Calcium antagonists protect against the cardiotoxic effects of catecholamine by preventing the generation of plasma borne cytotoxic compounds, which are probably free radicals.     

Endothelin-3 regulates endothelin-1 production in cultured human endothelial cells.

Effects of endothelin-3 on the secretion of endothelin-1 and other endothelium-derived substances were investigated in cultured human umbilical vein endothelial cells. The present binding study showed two distinct subpopulations of binding sites for endothelin-3 with higher and lower affinities in cultured human endothelial cells. Endothelin-3 caused an increase in intracellular Ca2+ and inositol 1,4,5-trisphosphate levels and activated protein kinase C in a dose-dependent manner. Endothelin-3 also caused an increase in [3H]thymidine incorporation into cellular DNA and stimulated the production of cyclic guanosine 3',5'-monophosphate, 6-ketoprostaglandin F1 alpha, and immunoreactive endothelin-1 in cultured human endothelial cells. NG-Monomethyl L-arginine (3 x 10(-4) mol/l) and indomethacin (10(-5) mol/l) enhanced endothelin-3-induced endothelin-1 production. These results suggest that endothelin-3 bound to its specific receptors and then caused phosphoinositide breakdown, subsequently mobilizing intracellular Ca2+ and leading to protein kinase C activation and the initiation of DNA synthesis, resulting in the stimulation of endothelin-1 production by human endothelial cells. Furthermore, this endothelin-1 production may be suppressed by endothelium-derived relaxing factor and prostacyclin produced in response to endothelin-3 in cultured human endothelial cells.     

Glucose-induced production of type IV collagen and laminin P1 from cultured human umbilical vein endothelial cells

To study the effect of high glucose on the production of type IV collagen and laminin P1 from the cultured human umbilical vein endothelial cells (HUVEC), we measured type N collagen and laminin P1 from HUVEC that were cultured under different conditions. The concentrations of type IV collagen in the cultured medium for high glucose (30 mM d-glucose), l-glucose (30 mM), or mannitol (30 mM). The increase of type IV collagen was dependent on the glucose concentration in the medium. The contents of type IV collagen in the cultured cells were also increased in high-glucose incubation compared with low glucose or l-glucose incubation. In contrast, the levels of laminin P1 in the medium cultured with high glucose were similar to those with low glucose or l-glucose. These results suggest that the increased production of type IV collagen may contribute to the thickening of basement membranes and may be linked to the development of diabetic nephropathy.     

Thrombin-mediated release of factor VIII antigen from human umbilical vein endothelial cells in culture

We have examined the effects of purified human alpha-thrombin on factor VIII antigen (FVIII-Ag) release by human umbilical vein endothelial cells in culture. Alpha-thrombin induced a time and dose-dependent release of FVIII-Ag into supernatant medium. Alpha-thrombin-mediated FVIII-Ag release was not dependent on protein synthesis and was observed in both serum-free and serum-containing media. FVIII-Ag release, however, was prevented when the serine esterase activity of thrombin was inhibited. Pretreatment of human endothelial cells with alpha-thrombin, but not diisofluorophosphate-thrombin, prevented subsequent FVIII-Ag release by alpha-thrombin. Thrombin-mediated FVII- Ag release was not associated with significant 51Cr release from prelabeled endothelial monolayers. We conclude that alpha-thrombin induces release of preformed FVIII-Ag from human umbilical vein endothelial cells by a receptor-independent, nonlytic mechanism requiring serine esterase activity.     

Regulation of arachidonic acid release by calcium influx in human endothelial cells.

In response to stimuli, endothelial cells release arachidonic acid, a lipid precursor of various vasoactive substances. We have investigated the relationships between cytosolic Ca2+ movements and arachidonic acid release in human umbilical vein endothelial cells. Histamine, a receptor-dependent agonist, and thapsigargin, a specific inhibitor of sarco-/endoplasmic Ca2+ pumps, time- and dose-dependently increased the release of [1-14C]-arachidonic acid. This release was inhibited by AACOCF3, a selective inhibitor of cytosolic phospholipase A2 (PLA2). In the absence of Ca2+ influx, arachidonic acid release was suppressed in both histamine- and thapsigargin-stimulated cells, despite marked elevations of cytosolic Ca2+ concentration ([Ca2+]i). In the presence of Ca2+ influx, arachidonic acid release was reduced in cells treated with BAPTA, an intracellular Ca2+ buffer, or with SK&F 96365, a receptor-operated Ca2+ channel blocker. Arachidonic acid release was analyzed as a function of the two successive phases of Ca2+ response to stimulation: Ca2+ peak and plateau phase, reflecting Ca2+ mobilization from internal stores and Ca2+ influx, respectively. The amount of arachidonic acid released was directly related to [Ca2+]i values measured at the influx phase with a 80 nM [Ca2+]i threshold, similar to that reported for PLA2 translocation. This suggests that Ca2+ entry from the extracellular space is essential for activating cytosolic PLA2 in human endothelial cells.     

Monocytes enhance endothelial von Willebrand factor release and prostacyclin production with different kinetics and dependency on intercellular contact between these two cell types.

Human umbilical vein endothelial cells cultured on a collagen lattice were used to study the effects of the interaction between human monocytes and endothelial cells on endothelial von Willebrand Factor (vWF) release and prostacyclin (PGI2) production by these cells. The effects of monocytes were compared with those of other leucocytes, conditioned media from monocytes, and agonists such as interleukin 1 (IL-1) and the phorbol ester PMA. Because the cell culture system used allows simultaneous analysis of the lumenal and ablumenal compartment of endothelial cell monolayers, we also studied into which direction these products were released by endothelial cells. Under quiescent conditions the concentration of vWF in the ablumenal compartment was about three-fold higher than that in the lumenal compartment, whereas PGI2 was equally distributed between the two compartments. Direct cell-cell contact between purified monocytes and endothelial cells strongly enhanced both vWF release and PGI2 synthesis, in a dose-dependent and monocyte-specific manner. The monocyte-induced enhancement of PGI2 production, however, was much earlier in onset than that of vWF. Secretory products from monocytes also enhanced endothelial PGI2 synthesis, although to a lesser extent than with monocytes that were in direct contact with endothelial cells. In contrast, the monocyte-induced enhancement of endothelial vWF release was completely dependent on the direct interaction between monocytes and endothelial cells.     

Human leukocyte cathepsin G and elastase specifically suppress thrombin- induced prostacyclin production in human endothelial cells

Polymorphonuclear leukocytes (PMN) when activated release products that can potentially injure endothelial cells or alter endothelial function. Exposure of cultured human umbilical vein endothelial cells to cathepsin G and elastase isolated from human PMN at concentrations reached in vivo (100 ng/mL to 10 micrograms/mL) selectively inhibited thrombin-induced prostacyclin production and the thrombin-induced rise in cytosolic free calcium ([Ca++]i) concentration. These proteases also blocked thrombin-induced release of arachidonic acid from prelabeled endothelial cells (EC). In contrast, induction of prostacyclin (PGI2) production by arachidonate, histamine, or the calcium ionophore A23187 was not altered by treatment of EC with these proteases. The effects of the proteases were concentration-dependent, were blocked by serum or serum protease inhibitors, and were reversed when the endothelial cells were further cultured for 24 hours in the absence of the proteases. Elastase, but not cathepsin G, also produced detachment of endothelial cells. Thus, the major leukocyte proteases selectively suppress thrombin-induced prostacyclin production by human vascular endothelial cells and may alter the hemostatic balance at sites of PMN activation.