姜黄素对内皮祖细胞功能及内皮型—氧化氮合酶的影响

目的观察姜黄素对体外培养的人外周血内皮祖细胞（EPCs）数量及功能的影响。方法采用贴壁选择法培养人外周EPCs，培养6d后，收集贴壁细胞并加入姜黄素（0、5、10、15μmol／L）培养一定时间（6、12、24和48h）。荧光显微镜鉴定EPCs，分别观察EPCs的体外增殖、黏附、迁移、体外血管生成能力。Griess法检测NO分泌量，并RT-PCR半定量测定eNOS基因表达。结果姜黄素增加外周血EPCs的数量，改善EPCs的体外增殖、黏附、迁移、体外血管生成能力（P〈0．01）。并上调eNOS基因表达，促进EPCs来源的NO的释放（P〈0．01）。结论姜黄素增加体外EPCs数量及改善其功能，上调eNOS基因表达并增加EPCs来源的NO分泌。     

黄芪甲苷对人外周血内皮祖细胞体外血管生成能力的影响

目的观察黄芪甲苷对体外培养的人外周血内皮祖细胞(EPCs)数量及增殖、迁移、黏附功能、血管生成能力的影响。方法密度梯度离心法获取人外周血单个核细胞,FITC标记荆豆凝集素Ⅰ(FITC-UEA-I)、DiI标记的乙酰化低密度脂蛋白(DiI-acLDL)荧光双染鉴定,流式细胞仪检测细胞表面标志。单个核细胞培养4d后进行实验分组,分为对照组和黄芪甲苷干预组。干预组加入不同浓度的黄芪甲苷(分别为10μg/mL、20μg/mL、40μg/mL)培养72h。分别采用四氮唑溴盐比色法、改良的Boyden小室和黏附能力测定来观察EPCs的增殖、迁移和黏附能力;体外血管生成试剂盒来观察EPCs体外血管生成能力。结果与正常对照组比较,黄芪甲苷组EPCs数量增加,EPCs的黏附、迁移、增殖和体外血管形成能力增强,且黄芪甲苷20μg/mL时作用最显著。结论黄芪甲苷可增加体外培养的EPCs数量,改善EPCs增殖、迁移、黏附和体外血管生成能力等生物学功能。     

阿托伐他汀对同型半胱氨酸所诱导内皮祖细胞功能损伤的保护作用

目的:探讨同型半胱氨酸(homocysteine,Hcy)诱导小鼠骨髓内皮祖细胞(endothelial progenitor cells,EPCs)功能损伤的氧化应激机制及阿托伐他汀的拮抗作用。方法:密度梯度离心法获取小鼠骨髓单个核细胞,培养7 d后收集贴壁细胞,FITC-UEA-1荧光染色鉴定EPCs。EPCs与不同浓度Hcy(0μmol/L,50μmol/L,500μmol/L)共孵育24 h或分别经不同浓度的阿托伐他汀(0.1μmol/L,1μmol/L,10μmol/L)预孵育0.5 h后,再加入500μmol/LHcy共孵育24 h。用MTT比色法,改良Boyden小室、黏附能力测定和体外血管生成试剂盒,分别观察EPCs的增殖能力、迁移能力、黏附能力和体外血管生成能力。荧光探针H2DCF-DA法检测细胞内活性氧水平,光泽精化学发光法检测NADPH氧化酶活性,硝酸还原酶法测定细胞培养液中一氧化氮(NO)含量,RT-PCR法测定eNOS基因表达。结果:Hcy诱导EPCs增殖、迁移、黏附和体外血管生成功能下降,活性氧的产生及NADPH氧化酶的活性增加,eNOS基因表达及细胞培养液中NO含量减少,与无Hcy处理组相比有明显差异(P0.05或P0.01)。与500μmol/L Hcy组相比,阿托伐他汀预处理可呈剂量依赖性地拮抗Hcy诱导的上述改变(P0.05或P0.01)。结论:Hcy可能通过激活NADPH氧化酶,诱导EPCs活性氧的产生及降低eNOS基因表达和NO水平,导致EPCs增殖、迁移、黏附和体外血管生成功能下降。阿托伐他汀部分拮抗Hcy的作用。     

血管内皮生长因子调节内皮祖细胞生物学功能

目的研究血管内皮生长因子（VEGF）对体外培养骨髓源性内皮祖细胞（EPCs）数量及增殖、迁移、黏附功能的影响及机制初探。方法密度梯度离心法获取骨髓单个核细胞,FITC-荆豆凝集素I、DiI-乙酰化低密度脂蛋白荧光双染鉴定。单个核细胞培养7d后分为对照组和VEGF干预组。VEGF干预组加入不同浓度VEGF（25,50,75,100μg／L）培养48h,分别采用四氮唑溴盐比色法、改良的Boyden小室和黏附能力测定观察EPCs的增殖、迁移和黏附能力。RT—PCR法半定量检测VEGF对EPCs内皮型一氧化氮合酶（eNOS）mRNA表达的影响。硝酸还原酶法比色测定VEGF对EPCs分泌一氧化氮的影响。结果VEGF可浓度依赖性地增加EPCs数量并明显促进EPCs的黏附、迁移和增殖能力,与对照组比较差异显著。VEGF可上调EPCseNOSmRNA的表达,促进EPCs分泌一氧化氮。结论VEGF可能通过上调EPCseNOSmRNA的表达影响EPCs部分生物学功能。     

2型糖尿病患者外周血内皮祖细胞数量和功能的变化

目的观察2型糖尿病（DM）患者外周血内皮祖细胞（EPCs）数量和功能的改变。方法选择2型DM患者16例和对照组19例，密度梯度离心法收集外周血单个核细胞（MNCs），诱导分化培养7d后，荧光染色和流式细胞术分别鉴定贴壁细胞为EPCs。采用二苯基四氮唑嗅盐（MTT）比色法、黏附能力测定实验和体外血管生成实验检测EPCs的增殖能力、黏附能力和体外血管生成能力。结果2型DM患者外周血EPCs数量明显减少[（3．1±1．2）×10^5]：[（3．9±1．1）×10^5]，P〈0．05。且2型DM患者外周血EPCs黏附能力[（50±15）：（60±11）细膨×200视野，P〈0．05]，增殖能力[（0．170±0．056）：（0．225±0．071）OD值，P〈0．05]，体外血管生成能力均明显受损。结论2型DM患者外周血EPCs的数量减少，且其增殖、黏附和血管生成能力受损。     

老年稳定型心绞痛患者外周血中内皮祖细胞变化及其影响因素

目的观察老年稳定型心绞痛（SA）患者外周血中内皮祖细胞（EPCs）数量及功能的变化,初步探讨心血管危险因素对其影响。方法选择老年SA患者和年龄匹配的对照者各20例,用密度梯度离心法从外周血中分离单个核细胞,用流式细胞仪测量外周血中CD＋细胞以鉴定EPCs,并进一步用倒置荧光显微镜鉴定FITC标记荆豆凝集素Ⅰ（FITC—UEA—Ⅰ）和DiⅠ标记的乙酰化低密度脂蛋白（DiLDL）双染色阳性细胞为正在分化的EPCs。采用黏附能力测定试验、改良Boyden小室和体外血管生成试剂盒分别观察EPCs的黏附能力、迁移能力和体外生成血管能力。结果老年SA患者外周血中EPCs数量明显低于对照组,其黏附能力、迁移能力和体外生成血管能力也明显受损。SA组患者EPCs数量与收缩压、空腹血糖水平呈负相关。结论老年SA患者外周血中EPCs数量降低且功能减退,其数量降低与高血压、糖尿病有关。     

阿司匹林对内皮祖细胞功能及其诱导型一氧化氮合酶的影响

目的:观察阿司匹林对外周血内皮祖细胞(endothelial progenitor cells,EPCs)数量和功能的影响。方法:采用密度梯度离心法从外周血获得单个核细胞,将其接种在人纤维连接蛋白包被的培养板上,培养7d后收集贴壁细胞,分别加入不同浓度阿司匹林(分别为1、2、5、10mmol/L)培养3、6、12、24h。激光共聚焦显微镜鉴定FITC-UEA-I和Dil-acLDL双染色阳性细胞为正在分化的EPCs,将其在倒置荧光显微镜下计数。然后分别采用MTT比色法、改良的Boyden小室、黏附能力测定实验和体外血管形成试剂盒来观察EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,免疫印迹杂交法(Western blot)半定量测定诱导型一氧化氮合酶(iNOS)含量。结果:阿司匹林能减少外周血EPCs数量,并且EPCs数量随阿司匹林浓度和作用时间增加而减少。EPCs的增殖能力、迁移能力、黏附能力、体外血管形成能力和iNOS含量亦随阿司匹林浓度和作用时间增加而降低。结论:阿司匹林通过减少EPCs中iNOS含量,降低EPCs的增殖能力、迁移能力、黏附能力和体外血管形成能力,从而抑制内皮细胞的生成。     

罗格列酮钠对中年男性糖尿病患者外周血内皮祖细胞的影响

目的观察罗格列酮钠对中年男性糖尿病患者血管内皮祖细胞（EPCs）数量和功能的影响。方法本实验纳入血糖控制良好（HbA1c〈7%）的30例中年男性糖尿病患者。体内实验：将上述患者随机分成罗格列酮钠组和常规治疗组。所有患者在用药前后均采集空腹静脉血,分离并培养EPCs,采用流式技术、免疫荧光双染法、MTT比色法、30 min贴壁方法、改良型Boyden小室法对EPCs进行计数、鉴定、增殖、黏附和迁移等功能检测。体外实验：随机抽取上述患者20例,提取其空腹静脉血单个核细胞,培养6 d后收集贴壁细胞,将收集到的每份贴壁细胞各分成药物干预组和对照组,用上述方法观察体外药物干预对EPCs数量和功能的影响。结果罗格列酮钠组用药后较用药前,CD3＋4/CD1＋33、vWF＋细胞数量增加,细胞增殖、黏附、迁移功能增强（P〈0.05或〈0.01）;较常规治疗组用药后,CD3＋4/CD1＋33、CD1＋33/KDR＋、vWF＋细胞数量增加,增殖、黏附、迁移功能增强（P〈0.01）。药物干预组EPCs增殖、黏附、迁移功能较对照组增强（P〈0.01）。结论罗格列酮能增加糖尿病患者EPCs数量,并能改善其增殖、黏附和迁移功能,且此作用独立于降糖、降压作用之外。     

糖基化终末产物对人外周血内皮祖细胞数量及功能的影响

目的观察糖基化终末产物(AGEs)对体外培养的人外周血内皮祖细胞(EPCs)数量及功能的影响。方法体外培养的人外周血EPCs根据不同AGEs-人血白蛋白(HSA)浓度分为对照纽、正常组(终浓度7.5 mg/L)、干预1组(终浓度1 5 mg/L)干预2组(终浓度30 mg/L)和干预3组(终浓度60 mg/L)。采用密度梯度离心法获取人外周血单个核细胞;激光共聚焦显微镜检测其对FITC标记荆豆凝集素-1的吸附和Dil-标记乙酰化低密度脂蛋白进行细胞功能鉴定;加入AGEs后,分别采用MTT法、Boyden小室测定EPCs的增殖、迁移能力;人纤维连接蛋白检测EPCs的黏附能力;用体外血管生成分析试剂盒检测不同浓度AGEs HSA作用后的EPCs成血管能力。结果高浓度AGEs可减少EPCs贴壁细胞数量(P<0.01),减弱EPCs的黏附(P<0.01)、增殖(P<0.01)、迁移(P<0.05)和成血管能力(P<0.01)。结论 AGEs可减少人外周血EPCs的数量并使用其功能受损。     

雌二醇对骨髓内皮祖细胞部分生物学功能的影响

目的观察雌二醇对体外培养骨髓来源内皮祖细胞(endothelial progenitor cells,EPCs)数量及增殖、迁移、黏附功能的影响。方法密度梯度离心法获取骨髓单个核细胞,FITC-荆豆凝集素I、DiI-乙酰化低密度脂蛋白荧光双染鉴定。单个核细胞培养4天后进行实验分组,分为对照组和雌二醇治疗组。雌二醇治疗组加入不同浓度雌二醇(分别为0.001、0.01、0.1μmol/L)培养48 h,然后分别采用四氮唑溴盐比色法、改良的Boyden小室和黏附能力测定来观察EPCs的增殖、迁移和黏附能力。结果雌二醇剂量依赖性增加EPCs数量并显著改善了EPCs的黏附、迁移和增殖能力,与对照组比较差异显著。结论雌二醇可增加培养EPCs的数量并改善EPCs部分生物学功能。     

Aprotinin impairs coronary endothelial function and down-regulates endothelial NOS in rat coronary microvascular endothelial cells

OBJECTIVE: The non-specific serine protease inhibitor aprotinin is currently used to reduce blood loss and the need for blood transfusion after cardiopulmonary bypass. We have recently reported that aprotinin impairs endothelium-dependent but not endothelium-independent relaxations in rat thoracic aortic rings due to its inhibitory effect on endothelial nitric oxide (NO) production. In light of these findings, the current study was designed to investigate the effects of aprotinin on coronary endothelial function in isolated rat hearts and on the expression of endothelial NO synthase (eNOS) in cultured rat coronary microvascular endothelial cells (CMEC). METHODS: Hearts obtained from Sprague-Dawley rats were perfused on a constant flow Langendorff isolated heart system and coronary perfusion pressure and cardiac parameters were recorded. The coronary relaxant responses to bolus infusions of bradykinin (BK) and sodium nitroprusside (SNP) were recorded in the absence and presence of aprotinin. Total RNA and protein samples were extracted from CMEC incubated with aprotinin or the vehicle, 0.9% NaCl. RT-PCR-Southern blotting and Western analyses were carried out to assess eNOS mRNA and protein levels, respectively. RESULTS: Aprotinin (125 and 250 kIU/ml) increased coronary perfusion pressure without changing the heart rate and cardiac contractility. Aprotinin inhibited BK-induced coronary vasodilatation at 250 kIU/ml, but not at 125 kIU/ml concentrations. The relaxant response to SNP did not change in response to either concentration of the drug. Incubation of CMEC with aprotinin down-regulated eNOS mRNA and protein at 250 kIU/ml, but not at 125 kIU/ml concentration. CONCLUSION: These data suggest that aprotinin selectively inhibits NO synthesis at higher doses (> or = 250 kIU/ml) and therefore impairs endothelium-dependent coronary vascular tone. This effect of the drug may contribute to its 'blood-sparing' action, but may also account for the increase in the incidence of postoperative graft thrombosis observed in clinical practice during aprotinin therapy.     

Neuropilin-1 regulates vascular endothelial growth factor-mediated endothelial permeability

Neuropilin-1 (Npn-1) is a cell surface receptor that binds vascular endothelial growth factor (VEGF), a potent mediator of endothelial permeability, chemotaxis, and proliferation. In vitro, Npn-1 can complex with VEGF receptor-2 (VEGFR2) to enhance VEGFR2-mediated endothelial cell chemotaxis and proliferation. To determine the role of Npn-1/VEGFR2 complexes in VEGF-induced endothelial barrier dysfunction, endothelial cells were stably transfected with Npn1 or VEGFR2 alone (PAE/Npn and PAE/KDR, respectively), or VEGFR2 and Npn-1 (PAE/KDR/Npn-1). Permeability, estimated by measurement of transendothelial electrical resistance (TER), of PAE/Npn and PAE/KDR cell lines was not altered by VEGF165. In contrast, TER of PAE/KDR/Npn-1 cells decreased in dose-dependent fashion following VEGF165 (10 to 200 ng/mL). Activation of VEGFR2, and 2 downstream signaling intermediates (p38 and ERK1/2 MAPK) involved in VEGF-mediated permeability, also increased in PAE/KDR/Npn-1. Consistent with these data, inhibition of Npn-1, but not VEGFR2, attenuated VEGF165-mediated permeability of human pulmonary artery endothelial cells (HPAE), and VEGF121 (which cannot ligate Npn-1) did not alter TER of HPAE. Npn-1 inhibition also attenuated both VEGF165-mediated pulmonary vascular leak and activation of VEGFR2, p38, and ERK1/2 MAPK, in inducible lung-specific VEGF transgenic mice. These data support a critical role for Npn-1 in regulating endothelial barrier dysfunction in response to VEGF and suggest that activation of distinct receptor complexes may determine specificity of cellular response to VEGF.     

Cellular biomarkers of endothelial health: microparticles,endothelial progenitor cells,and circulating endothelial cells

Endothelial dysfunction, the shift from a healthy endothelium to a damaged pro-coagulative, pro-inflammatory, and pro-vasoconstrictive phenotype, is an early event in many chronic diseases that frequently precedes cardiovascular complications. Functional assessment of the endothelium can identify endothelial damage and predict cardiovascular risk; however, this assessment provides little information as to the mechanisms underlying development of endothelial dysfunction. Changes in plasma asymmetric dimethyl arginine levels, markers of lipid peroxidation, circulating levels of inflammatory mediators, indices of coagulation and cellular surrogates such as microparticles, circulating endothelial cells, and endothelial progenitor cells may reflect alterations in endothelial status and as such have been defined as “biomarkers” of endothelial function. Biomarkers may be chemical or cellular. This review examines some markers of endothelial dysfunction, with a particular focus on cellular biomarkers of endothelial dysfunction and their diagnostic potential.     

NADPH oxidase mediates vascular endothelial cadherin phosphorylation and endothelial dysfunction

Vascular endothelial activation is an early step during leukocyte/endothelial adhesion and transendothelial leukocyte migration in inflammatory states. Leukocyte transmigration occurs through intercellular gaps between endothelial cells. Vascular endothelial cadherin (VE-cadherin) is a predominant component of endothelial adherens junctions that regulates intercellular gap formation. We found that tumor necrosis factor (TNF) caused tyrosine phosphorylation of VE-cadherin, separation of lateral cell-cell junctions, and intercellular gap formation in human umbilical vein endothelial cell (HUVEC) monolayers. These events appear to be regulated by intracellular oxidant production through endothelial NAD(P)H (nicotinamide adenine dinucleotide phosphate) oxidase because antioxidants and expression of a transdominant inhibitor of the NADPH oxidase, p67(V204A), effectively blocked the effects of TNF on all 3 parameters of junctional integrity. Antioxidants and p67(V204A) also decreased TNF-induced JNK activation. Dominant-negative JNK abrogated VE-cadherin phosphorylation and junctional separation, suggesting a downstream role for JNK. Finally, adenoviral delivery of the kinase dead PAK1(K298A) decreased TNF-induced JNK activation, VE-cadherin phosphorylation, and lateral junctional separation, consistent with the proposed involvement of PAK1 upstream of the NADPH oxidase. Thus, PAK-1 acts in concert with oxidase during TNF-induced oxidant production and loss of endothelial cell junctional integrity.     

Nifedipine improves endothelial function: role of endothelial progenitor cells

Nifedipine has been shown to improve endothelial function. Recent studies have indicated that endothelial function is correlated with the number of circulating endothelial progenitor cells (EPCs), but it is unclear whether nifedipine affects the number and function of EPCs. The aims of this study were to determine the effects of nifedipine on the number and function of EPCs and to investigate the relationship between improvement of endothelial function and EPC numbers in patients with hypertension. Stage 1 hypertensive men (n=37) were randomly divided into the nifedipine group and the control untreated group. The nifedipine group was administered slow-release nifedipine (20 mg) once daily. At baseline and after 4 weeks, flow-mediated dilation, blood pressure, biochemical data, and number of circulating CD34+CD133+ progenitor cells and EPCs were measured. The direct effects of nifedipine on EPC number and function were assessed in vitro. In the nifedipine group, flow-mediated dilation and the numbers of circulating CD34+CD133+ progenitor cells and EPCs were increased, along with a decrease of serum malondialdehyde low-density lipoprotein. The improvement of flow-mediated dilation by nifedipine was correlated with the increase of circulating CD34+CD133+ progenitor cells. Nifedipine also improved angiogenesis-related functions of EPCs (differentiation, migration, and resistance to oxidative stress) in vitro. Thus, nifedipine improved endothelial function and EPC function in stage 1 hypertensive subjects. The latter action may be mediated by reduction of oxidative stress and suppression of EPC apoptosis. These results demonstrate that nifedipine preserves endothelial integrity in patients with hypertension, at least partly, by enhancing EPC numbers and activity.     

Role of endothelial cell cytoskeleton in control of endothelial permeability

Increased permeability of the pulmonary microvasculature is felt to cause acute noncardiogenic lung edema, and histological studies of edematous lungs show gaps between apparently healthy endothelial cells. To determine whether alterations in endothelial cell cytoskeletons would alter endothelial permeability, we exposed monolayers of pulmonary artery endothelial cells grown on micropore filters to cytochalasin B or D. Cytochalasin exposed monolayers demonstrated a 2- to 3-fold increase in endothelial permeability that was readily reversible by washing the monolayers free of cytochalasins. Parallel phase contrast and fluorescence microscopy demonstrated retraction of cell cytoplasm and disruption of bundles of microfilaments in cytochalasin exposed cells. These changes also were readily reversed after washing the cells free from cytochalasins. To test the relevance of these findings to an in situ microvasculature, we added cytochalasin B to the perfusate of isolated rabbit lungs and observed that cytochalasin B caused a high permeability lung edema. These studies suggest that endothelial cell cytoskeletons may be important determinants of endothelial permeability.     

Vascular endothelial growth factor-C enhances radiosensitivity of lymphatic endothelial cells

Radiation therapy after lymph node dissection increases the risk of developing painful and incurable lymphedema in breast cancer patients. Lymphedema occurs when lymphatic vessels become unable to maintain proper fluid balance. The sensitivity of lymphatic endothelial cells (LECs) to ionizing radiation has not been reported to date. Here, the radiosensitivity of LECs in vitro has been determined using clonogenic survival assays. The ability of various growth factors to alter LEC radiosensitivity was also examined. Vascular endothelial growth factor (VEGF)-C enhanced radiosensitivity when LECs were treated prior to radiation. VEGF-C-treated LECs exhibited higher levels of entry into the cell cycle at the time of radiation, with a greater number of cells in the S and G2/M phases. These LECs showed higher levels of γH2A.X—an indicator of DNA damage—after radiation. VEGF-C did not increase cell death as a result of radiation. Instead, it increased the relative number of quiescent LECs. These data suggest that abundant VEGF-C or lymphangiogenesis may predispose patients to radiation-induced lymphedema by impairing lymphatic vessel repair through induction of LEC quiescence.