血流剪切力对静脉桥血管再狭窄影响的研究进展

正大隐静脉因其易得、长度足够且较为匹配等特点是冠状动脉搭桥术中广泛使用的血管材料,然而静脉桥具有较高的再狭窄率,术后10年约50%的静脉桥血管发生狭窄或闭塞。造成静脉桥血管再狭窄的因素较多,如获取静脉血管时的操作损伤、缺血再灌注,早期血管内血栓形成,内膜细胞的增殖、血小板及白细胞的黏附及平滑肌细胞的增生等。静脉桥     

血流影响下内皮细胞与平滑肌细胞的交互作用

血管壁的内皮细胞(ECs)和平滑肌细胞(SMCs)的交互作用对维持血管功能和动脉粥样硬化(AS)的发生发展有着重要意义。局部血流动力学环境,尤其是流体剪切力(FSS)与血管壁之间的相互作用对AS斑块的分布起着重要作用。FSS下ECs和SMCs的交互作用会对ECs和SMCs的形态和表型、增殖和迁移、炎性细胞的黏附产生影响。本文主要对FSS下ECs和SMCs的交互作用作一综述。     

失血性休克大鼠内皮细胞蛋白C受体表达的研究

30只健康SD大鼠随机分为正常对照组、假休克组、失血性休克组,采用ELISA、RT-PCR、Western blot技术分别对3组血浆中可溶性内皮细胞蛋白C受体(sEPCR)水平和小肠组织EPCR mRNA及蛋白的表达进行检测.发现失血性休克组sEPGR平均水平较正常对照组、假休克组增高;失血性休克组EPCR mRNA平均水平较正常对照组、假休克组明显增高,失血性休克组:EPCR蛋白水平较正常对照组、假休克组明显下降.认为失血性休克大鼠外周血循环系统sEPCR升高可能是早期诊断该病的一个可靠指标,其水平高低可能反映疾病的预后.     

钙敏感受体在动脉粥样硬化大鼠血管内皮细胞中的表达

目的探讨钙敏感受体在动脉粥样硬化大鼠胸主动脉血管内皮细胞中的表达及其与细胞凋亡的关系。方法 Wistar大鼠144只,随机分为对照组和动脉粥样硬化组,每组72只。动脉粥样硬化早期模型复制首先每千克体重注射维生素D360万单位,然后喂养高脂饲料6周。自动生化仪检测血清甘油三酯、总胆固醇;光镜观察胸主动脉形态学变化;TUNEL染色观察胸主动脉内皮细胞凋亡情况;采用RT-PCR和免疫印迹法分别检测胸主动脉血管内皮细胞中钙敏感受体、Bax、Bcl-2及Caspase-3的mRNA和蛋白表达。结果与对照组比较,动脉粥样硬化组细胞凋亡指数以及钙敏感受体、Bax和Caspase-3的表达升高,Bcl-2的表达降低;光镜下可见胸主动脉部分内皮脱落,表面不光滑,中膜平滑肌细胞数目明显增多,排列紊乱。结论钙敏感受体可能参与了主动脉血管内皮细胞的凋亡,进而启动动脉粥样硬化的形成。     

C反应蛋白对血管内皮细胞表达糖基化终产物受体和MCP-1的影响

目的研究C反应蛋白（C-RP）对内皮细胞（Ec）晚期糖基化终产物受体（RAGE）的影响,及RAGE在C-RP促动脉粥样硬化中的作用。方法在不同时间用不同剂量C-RP刺激EC。用Western blot检测CRP对RAGE蛋白表达的影响,RT-PCR研究RAGEmRNA的变化。利用特异的小分子干扰RNA（siRNA）敲低RAGE基因表达,通过ELISA方法检测各组培养液中单核细胞趋化蛋白1（MCP-1）水平变化。结果与对照组相比,C-RP刺激可以增加EC的RAGE蛋白和mRNA的表达（P〈O．05）,并且旱浓度-时间依赖性。在干扰RAGE基因表达后,C-RP促MCP-1分泌作用消失。结论c反应蛋白可以增加糖基化终产物受体蛋白和mRNA表达水平,并通过RAGE促进MCP1水平的增加。     

血管内皮细胞生长因子受体基因启动子区多态性与脑卒中的关系

目的:探讨血管内皮细胞生长因子受体(VEGFR-2)基因启动子区多态性与脑卒中患病风险的关系。方法:利用多中心病例—对照研究,对1849例脑卒中患者(血栓形成性脑梗塞812例,腔隙性脑梗塞530例,脑出血507例)和1798例对照检测VEGFR-2基因启动子多态-604T/C的频率分布,Logistic回归模型分析多态与脑卒中的相关性。测定荧光素酶活性,分析突变型多态对VEGFR-2基因转录活性的影响。结果:VEGFR-2基因多态-604TC和CC基因型频率在脑梗塞组显著低于对照组(脑梗塞者:TC36.7%,CC8.4%;对照组:TC41.8%,CC10.3%;P<0.01),脑梗塞者C等位基因频率显著低于对照组(26.7%比31.2%,P<0.01),均有显著性差异。-604C等位基因与脑梗塞的低发病风险相关(OR:0.78;95%CI:0.65～0.95;P<0.05)。多态-604C与野生型-604T相比,降低该基因的转录活性2.93倍。结论:VEGFR-2基因启动子变异-604C降低该基因的转录活性,并与降低脑梗塞的发病风险相关。其分子机制可能是由于VEGF/VEGFR-2信号通路下调,降低斑块内的新生血管化程度,从而延迟或减轻动脉粥样硬化的进展。     

血管紧张素II和缬沙坦对人脐静脉内皮细胞血凝素样氧化低密度脂蛋白受体表达的影响

目的　研究血管紧张素II(AngII)和AngIII型受体 (AT1)拮抗剂缬沙坦对人脐静脉内皮细胞 (HUVECs)血凝素样氧化低密度脂蛋白受体 (LOX 1)基因转录和蛋白表达的影响 ,以进一步探讨AngII和LOX 1在动脉粥样硬化 (AS)中的地位和相互关系 ,以及缬沙坦可能的抗AS作用。方法　将不同浓度AngII(1× 10 -5～ 1× 10 -10 mol/L)与HUVECs共孵育 2 4h ,以及将 1× 10 -6mol/L浓度的AngII与HUVECs作用不同时间 (0、3、6、12、2 4、36、4 8h)后 ,用细胞酶联免疫法和半定量RT PCR分别检测LOX 1蛋白和mRNA表达的情况 ,并观察缬沙坦对此的影响。结果　AngII呈浓度依赖方式诱导HUVECsLOX 1蛋白和mRNA表达增加 ;10 -6mol/L的AngII作用 3h ,内皮细胞LOX 1蛋白和mRNA表达即有显著增高 (P <0 0 0 1) ;随着时间延长 ,LOX 1蛋白和mRNA表达量逐渐增加 ,至 2 4～ 36h达最高峰。缬沙坦可显著抑制AngII诱导的HUVECsLOX 1表达 ,使LOX 1表达接近于正常水平。结论AngII能明显增强HUVECs表达LOX 1,并呈浓度和时间依赖性 ,这可能是AngII促进动脉粥样硬化发生、发展的机制之一 ;此作用可被AT1拮抗剂缬沙坦阻断 ,从而产生可能的抗AS作用。     

血液剪切力诱导的血管内皮细胞形态学变化和信号通路

近年来，对血管内皮细胞（ VEC ）的研究已从静态转移到模拟人体血液剪切力的动态上来。目前研究成果表明，剪切力把信号传递到VEC内引起细胞的反应，对血液凝固、纤维蛋白溶解、血管重建有重要意义。血液剪切力发生变化时，VEC会做出一系列应答，从而可能引发一些心血管疾病［1］。因此，通过对剪切力影响下VEC的形态和分子水平的研究，可为心血管疾病的预防、治疗及生物工程血管内皮细胞培养提供新的思路［2，3］。本文就剪切力和VEC的作用关系作一综述。     

内皮细胞蛋白C受体的研究进展

蛋白C途径是机体抗凝系统的重要组成部分，凝血酶在激活凝血过程与活化血小板中起着关键作用，但当凝血酶与内皮细胞表面血栓调节蛋白（TM）结合即启动蛋白C抗凝系统，活化蛋白C（APC）与辅因子蛋白S结合，灭活因子Ⅴa和Ⅷa，从而限制凝血酶的进一步产生。内皮蛋白C受体（endothelial protein C receptor，EPCR）是蛋白C系统新发现的成员，除调节蛋白C系统外还参与了炎症、凋亡、造血及免疫等诸多病理过程，与多种疾病的发生发展有关，已成为当前医学研究领域一个新的热点。     

IgA肾病患者血管内皮细胞生长因子及其受体的表达

肾小球内皮细胞是肾小球血管壁的重要组成部分 ,对于维护肾小球血管壁的完整性具有重要的意义。血管内皮细胞生长因子 (VEGF)能促进内皮细胞的增生、迁移 ,增强内皮细胞通透性。本研究通过观察IgA肾病患者肾组织内VEGF及其受体 (flk 1 )和Ⅳ型胶原的表达 ,分析VEGF、flk 1表达与IgA肾病患者尿蛋白、血压、血肌酐、肾小球Ⅳ型胶原表达的关系。一、对象与方法1 .对象 :IgA肾病患者 2 4例 ,男 1 4例 ,女 1 0例 ,年龄1 6～ 49岁 ,平均 (2 8 6± 1 1 7)岁。所有患者均行肾活检术 ,肾组织病理检查符合IgA肾病诊断。根据病理改变的程度分…     

Laminar shear stress up-regulates the expression of stearoyl-CoA desaturase-1 in vascular endothelial cells

OBJECTIVE: Laminar shear stress plays critical roles in vascular homeostasis and exerts various metabolic effects on endothelial cells (ECs). Stearoyl-CoA desaturase-1 (SCD1), which catalyzes the biosynthesis of monounsaturated fatty acids, affects the lipid composition and fluidity of the cell membrane. Thus, we examined the effect of laminar flow on SCD1 expression in ECs. METHODS: A flow chamber was used to impose a laminar shear stress on a confluent monolayer of human vascular ECs. The expression of SCD1 was examined using real-time RT-PCR and Northern and Western blotting. Immunohistochemical staining was used to assess the expression of SCD1 in Sprague-Dawley rat arteries, including the sites of arterial bifurcation. RESULTS: Laminar shear stress (12 dyn/cm2, 12 h) markedly increased the gene expression of SCD1 in ECs. The flow-induced SCD1 expression was attenuated by peroxisome proliferator-activated receptor (PPAR)-gamma antagonists both in vitro and in vivo. Troglitazone and rosiglitazone significantly increased the gene expression of SCD1. Furthermore, overexpression of a constitutively active PPARgamma induced the expression of SCD1 in ECs. Immunohistochemical study of cross-sections from rat celiac arteries revealed that endothelial expression of SCD1 was substantially higher on the medial division apex, where the shear stress is high and more laminar, than the lateral aspect, where the shear stress is low and unsteady. CONCLUSION: These in vitro and in vivo results demonstrate that laminar flow increased the expression of SCD1 in endothelium through a PPARgamma-specific mechanism, which may contribute to the shear stress-mediated protective roles in ECs.     

Effect of shear stress on asymmetric dimethylarginine release from vascular endothelial cells

We demonstrated recently that plasma concentrations of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide (NO) synthase, are increased by high salt intake concomitantly with a decrease in plasma levels of NO in human hypertension. We investigated the effect of shear stress on ADMA release in 2 types of cells: transformed human umbilical vein endothelial cells (HUVECs; cell line ECV-304) and HUVECs. Exposure of ECV-304 cells and HUVECs to shear stress with the use of a cone-plate viscometer enhanced gene expression of protein arginine methyltransferase (PRMT-1), ADMA synthase. In HUVECs, the ratio of PRMT-1 to glyceraldehyde 3-phosphate dehydrogenase mRNA was increased by 2-fold by a shear stress of > or =15 dyne/cm2. A dominant-negative mutant of IkappaB kinase alpha and troglitazone at 8 micromol/L, an activator of peroxisome proliferator-activated receptor gamma, abolished the shear stress-induced increase in PRMT-1 gene expression in parallel with the blockade of nuclear factor (NF)-kappaB translocation into the nucleus. The activity of dimethylarginine dimethylaminohydrolase, the degradation enzyme of ADMA, was unchanged after shear stress < or =15 dyne/cm2 and was enhanced by 1.48+/-0.06-fold (P<0.05) by shear stress at 25 dyne/cm2. The release of ADMA was increased by 1.64+/-0.10-fold (P<0.05) by shear stress at 15 dyne/cm2 but was not affected by shear stress at 25 dyne/cm2. These results indicate that shear stress enhances gene expression of PRMT-1 and ADMA release via activation of the NF-kappaB pathway. Shear stress at higher magnitudes facilitates the degradation of ADMA, thus returning ADMA release levels to baseline.     

Fluid shear stress induces lipocalin-type prostaglandin D(2) synthase expression in vascular endothelial cells

Ligands for peroxisome proliferator-activated receptor gamma, such as the thiazolidinedione class of antidiabetic drugs and 15-deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)), modulate various processes in atherogenesis. In search of cells that generate prostaglandin D(2) (PGD(2)), the metabolic precursor of 15d-PGJ(2), we identified PGD(2) from culture medium of endothelial cells. To study how PGD(2) production is regulated in endothelial cells, we investigated the role of fluid shear stress in the metabolism of PGD(2). Endothelial cells expressed the mRNA for the lipocalin-type PGD(2) synthase (L-PGDS) both in vitro and in vivo. Loading laminar shear stress using a parallel-plate flow chamber markedly enhanced the gene expression of L-PGDS, with the maximal effect being obtained at 15 to 30 dyne/cm(2). The expression began to increase within 6 hours after loading shear stress and reached the maximal level at 18 to 24 hours. In contrast, shear stress did not alter the expression levels of PGI(2) synthase and thromboxane A(2) synthase. In parallel with the increase in the expression level of L-PGDS, endothelial cells released PGD(2) and 15d-PGJ(2) into culture medium. These results demonstrate that shear stress promotes PGD(2) production by stimulating L-PGDS expression and suggest the possibility that a peroxisome proliferator-activated receptor gamma ligand is produced in vascular wall in response to blood flow.     

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。     

层流切应力刺激对人脐静脉血管内皮细胞Toll样受体mRNA表达的影响

目的用RT-PCR和Northern杂交技术,评价层流低切应力刺激对人脐静脉血管内皮细胞Toll样受体(TLR)表达的影响。方法将0.42 Pa切应力为低切应力组处理内皮细胞1 h,未作任何刺激的内皮细胞为对照组,从两组血管内皮细胞提取总RNA,采用RT-PCR和Northern杂交技术明确对照和切应力刺激1 h人脐静脉血管内皮细胞TLR-2和TLR-4 mRNA的表达情况。结果RT-PCR和Northern杂交均显示,层流低切应力刺激1 h后血管内皮细胞TLR-4表达增强、TLR-2几乎无变化。结论层流低切应力可引起人脐静脉内皮细胞TLR-4 mRNA表达增加,提示炎性信号受体TLR-4可能介导层流切应力诱导血管内皮细胞某些效应基因的表达。