供体年龄影响融合生长内皮祖细胞对平滑肌细胞表型转换及增殖迁移的作用

目的:探讨老龄和年轻个体来源融合生长状态内皮祖细胞(EPCs)对血管平滑肌细胞(SMCs)表型转换以及增殖和迁移的调节作用。方法:脱臼处死1~2月龄、19~26月龄SD大鼠,应用含15%FBS的DMEM/F12培养基(含内皮细胞生长添加剂100 mg/L、肝素100 mg/L、青霉素、链霉素各1×105U/L)培养EPCs,取1~2月龄大鼠腹主动脉,组织块法培养血管SMCs,应用Di I-Ac-LDL与FITC-UEA-1荧光双染以及α-SM-actin免疫荧光分别对EPCs和SMCs进行鉴定。建立细胞共培养体系,上室为融合生长状态的EPCs,下室为SMCs,实验分4组:(1)第3代SMCs(P3)组;(2)第4代SMCs(P4)组;(3)第4代SMCs与年轻大鼠来源EPCs共培养(P4YE)组;(4)第4代SMCs与老龄大鼠来源EPCs共培养(P4AE)组。Western blotting检测α-SM-actin和osteopontin蛋白的表达;[3H]-TdR掺入法检测SMCs增殖;细胞划痕实验检测SMCs的迁移能力。结果:与P3组相比,P4组的SMCsα-SM-actin表达显著下调,而osteopontin表达显著增强;P4YE组SMCs的α-SM-actin及osteopontin表达与P3组比较未见有显著差别;与P4组相比,年轻和老龄大鼠来源的EPCs均显著促进第4代SMCs的α-SM-actin和下调osteopontin的表达,抑制第4代SMCs的增殖和迁移;与老龄大鼠来源的EPCs相比,年轻大鼠来源的EPCs更能够显著延迟SMCs表型由收缩型向合成型转换,抑制SMCs增殖和迁移。结论:共培养融合生长状态的EPCs使血管SMCs表型转换延迟、抑制SMCs增殖和迁移,年轻大鼠来源的EPCs较老龄大鼠来源的EPC更显著延迟血管SMCs表型由收缩型向合成型转换,并具有更强的抑制血管SMCs增殖和迁移的能力。     

血管形成素-1与微血管通透性

血管形成素(Angiopoietin,Ang)为血管内皮细胞(endothelial cells,ECs)特异性受体酪氨酸激酶Tie-2的配体,是一类新发现的血管生成因子,它与血管内皮生长因子(vascularendothelial growth factor,VEGF)共同作用,协同调节血管的发生、形成过程[1]。Ang-1是Tie-2的主要生理配体,其功能涉及:募集与支持血管内皮周围细胞、诱导毛细血管发芽、ECs趋化反应和ECs网络形成[2]、与抗ECs凋亡有关[3,4]。Ang-1或Tie-2基因敲除的小鼠心脏、脑及卵黄囊血管系统的     

切应力对与血管平滑肌细胞联合培养的内皮细胞微管骨架重构的影响

目的探讨切应力对与血管平滑肌细胞(VSMCs)联合培养的内皮细胞(ECs)中微管的聚集重构的影响,为阐明应力诱导血管重建的分子机制提供一些实验证据。方法应用ECs与VSMCs联合培养的平行平板流动腔系统,给ECs面施加15dyne/cm2的层流切应力,以静态条件下联合培养的ECs为对照组,用WesternBlot、免疫荧光细胞化学和图像分析等技术,研究切应力作用下与VSMCs联合培养的ECs的微管聚集的变化。结果静态联合培养组,ECs微管骨架的排列是稀疏、发散和无规律的。切应力诱导了ECs的微管的重构,,微管骨架变得有序,朝切应力的方向规律的排列。切应力能够促进ECs的微管聚集,与对照组相比,切应力作用下的ECs内多聚微管的数量增加,切应力作用3h,ECs内多聚微管的数量达到峰值,之后开始下降。结论切应力诱导和促进了EC的微管骨架发生重构(聚集)。结果提示:微管可能是机械应力刺激作用的靶标,应力可能通过它改变ECs的形态,影响细胞的黏附与迁移等功能。     

张应变诱导分泌型miR-27a调控GRK6在高血压内皮细胞异常增殖中的机制研究

目的:本研究旨在揭示高血压条件下血管平滑肌细胞(vascular smooth muscle cells,VSMCs)响应高周期性张应变后调控血管内皮细胞(endothelial cells,ECs)异常增殖的可能机制。方法:在体条件下,构建腹主动脉缩窄型高血压大鼠模型;体外条件下,用FX-4000T张应变加载系统对VSMCs施加5%和15%的周期性张应变。结果:与正常组相比,高血压组大鼠胸主动脉ECs中GRK6的表达水平显著降低,ECs增殖水平显著上升;体内和体外条件均存在VSMCs源性MPs(VSMC-MPs);mi R-27a存在于VSMC-MPs中,并可靶向调控GRK6;15%周期张应变条件下产生的VSMC-MPs中mi R-27a的含量显著高于5%组,作用于ECs后,15%组ECs中mi R-27a的水平显著高于5%组,GRK6的表达水平显著低于5%组,ECs的增殖能力显著高于5%组;用从转染生物素连接的mi R-27a(B-mi R-27a)的VSMCs培养液中分离得到的MPs作用于ECs,在ECs中可以检测到B-mi R-27a的存在;mi R-27a正向调控ECs的增殖,GRK6负向调控ECs的增殖。结论:在高血压条件下,高周期性张应变促进VSMCs分泌mi R-27a,其可通过VSMC-MPs转移到ECs中,抑制GRK6表达,并最终诱导ECs异常增殖。     

切应力对与内皮细胞联合培养的血管平滑肌细胞粘附的影响及其机制

目的　细胞粘附是细胞迁移的关键性起始步骤。研究切应力和内皮细胞(endothelial cells, ECs)对血管平滑肌细胞(vascular smooth muscle cells, VSMCs)粘附的影响及其可能的信号通路，为探讨流体切应力诱导的血管壁细胞迁移行为的机制提供一些实验依据。方法　应用VSMCs和ECs联合培养流动腔系统，对ECs面施加1.5 Pa切应力，12 h；以静止状态下，单独培养的VSMCs以及与ECs联合培养的VSMCs 为对照，应用细胞粘附实验和Western Blot技术，观察切应力对与EC联合培养的VSMCs粘附的影响及蛋白激酶B(PKB/Akt)磷酸化水平表达变化。结果　静态联合培养12 h，VSMCs的粘附能力明显增强，同时磷酸化Akt的表达平行增高。切应力作用下，明显抑制了联合培养的VSMCs粘附，同时磷酸化Akt的表达平行降低。结论　生理大小切应力明显抑制了ECs诱导的VSMCs粘附，其中Akt信号通路起了关键作用。     

切应力与血管平滑肌细胞对内皮细胞增殖的影响及TGFβ1与p-Akt信号通路在其中的作用

目的探讨切应力与血管平滑肌细胞(VSMCs)对内皮细胞(ECs)增殖功能的影响及其一些分子机制。方法应用平行平板流动腔系统对单独培养的ECs以及与VSMCs联合培养的ECs施加15dyn/cm2(1dyn=10-5N)的正常切应力;Western blot技术检测反映细胞增殖能力的分子—增殖细胞核抗原(PCNA)的表达及细胞内信号转导分子Akt的磷酸化水平。静态条件下,以单独培养ECs为对照组,将ECs与VSMCs隔开培养,并应用TGFβ1封闭性抗体,观察TGFβ1在VSMCs诱导ECs增殖中的作用。结果正常切应力抑制了ECs增殖及p-Akt表达,VSMCs在与ECs联合培养及隔开培养时均明显促进ECs增殖及p-Akt表达。正常切应力部分逆转了联合培养VSMCs诱导的ECs增殖和p-Akt表达,而TGFβ1封闭性抗体能够拮抗隔开培养VSMCs诱导的ECs增殖和p-Akt表达。结论正常切应力可视为血管的保护因子,抑制ECs增殖;VSMCs通过旁分泌作用诱导了ECs增殖;TGFβ1及PI3/Akt信号分子参与了其调节过程。     

活化激酶C受体1在切应力调控血管平滑肌细胞增殖中的作用

目的 探讨活化激酶C受体1（receptor for actived C kinase 1, RACK1）在内皮细胞（endothelial cells, ECs）感受切应力刺激调控血管平滑肌细胞(vascular smooth muscle cells,VSMCs)增殖中的作用及其机制。方法 应用平行平板流动腔系统,对联合培养的大鼠ECs和VSMCs施加1.5 Pa正常切应力（normal shear stress, NSS）和0.5 Pa低切应力（low shear stress,LowSS）,应用BrdU ELISA方法检测VSMCs增殖水平,对蛋白质组学研究发现的力学响应分子RACK1表达以及Akt磷酸化,应用Western blot技术进行检测。静态条件下,应用RNA干扰技术特异性抑制VSMCs的RACK1表达,检测其对细胞增殖和Akt磷酸化的作用。应用ECs与VSMCs隔开培养和联合培养模型,检测ECs对VSMCs的RACK1表达和Akt磷酸化水平的影响。结果 血管差异蛋白质组学的结果发现,与NSS组相比,RACK1在LowSS组血管组织的表达水平明显升高。细胞实验结果显示,LowSS诱导了与ECs联合培养的VSMCs增殖,上调VSMCs的RACK1表达和Akt磷酸化。静态条件下,特异性抑制VSMCs的RACK1表达后,VSMCs的增殖水平和Akt磷酸化水平均显著下降。与ECs联合培养VSMCs,其RACK1表达和Akt磷酸化水平较隔开培养组均上调。结论 VSMCs的RACK1表达受细胞接触与切应力的影响,并可能通过PI3K/Akt信号通路参与LowSS诱导的VSMCs增殖的调控。探讨VSMCs增殖功能变化及其力学生物学机制对于认识动脉粥样硬化等疾病发病机理和疾病防治有重要意义。     

TNF-α促进内皮源性微体的数量与ICAM-1表达

目的探讨高张应变调控的肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)对内皮源性微体(endothelial microparticles,EMPs)数量与表面细胞间黏附分子-1(intercellular cell adhesion molecule-1,ICAM-1)表达的作用。方法采用Flexercell细胞张应变加载系统对大鼠胸主动脉内皮细胞(endothelial cells,ECs)分别施加5%(模拟正常生理状态)和18%(模拟高血压状态)幅度的周期性张应变,加载频率均为1.25 Hz,加载持续时间为24 h,实时PCR检测不同幅度张应变条件下ECs的TNF-αmRNA表达水平。之后应用TNF-α刺激大鼠胸主动脉ECs,收集上清液,超速离心提取得到内皮源性微体(endothelial microparticles,EMPs);用亲脂性苯乙烯基(lipophilic styryl)以及透射电镜对EMPs进行形态鉴定;流式细胞术对TNF-α刺激产生的Annexin V阳性EMPs进行计数,并检测EMPs表面ICAM-1的表达。结果与5%正常张应变组相比,18%高张应变条件下ECs的TNF-α表达水平显著上升。TNF-α能够显著上调ECs产生Annexin V阳性的EMPs数量,且TNF-α刺激ECs产生的EMPs表面ICAM-1表达量显著增加。结论高张应变条件下ECs高表达TNF-α可能介导了EMPs产生和表面ICAM-1高表达。研究结果为后续探讨EMPs在血管重建力学生物学机制中的作用提供新的实验证据。     

直接和间接共培养条件下小鼠子宫自然杀伤细胞与树突状细胞相互作用的比较

背景：子宫自然杀伤细胞与树突状细胞可以相互作用,但相互间作用是否必须直接接触还存在不同的观点。 目的：对比直接和间接共培养条件下子宫自然杀伤细胞与树突状细胞之间的相互作用,明确两者相互作用的方式。 方法：将树突状细胞和子宫自然杀伤细胞进行直接接触共培养,设为直接共培养组;在2种细胞Transwell系统中进行共培养,设为间接共培养组。观察培养细胞的生长状况,酶联吸附法检测培养上清白细胞介素10,12、转化生长因子β细胞因子的浓度,流式细胞术检测各组细胞表面标志CD86的表达情况。 结果与结论：与单独培养树突状细胞和子宫自然杀伤细胞相比,直接和间接共培养组培养液上清中白细胞介素10,12、转化生长因子β浓度均增加(P < 0.05),尤以白细胞介素10浓度增加明显(P < 0.05),CD86的表达明显增高 (P < 0.05)。直接共培养组白细胞介素10,12和转化生长因子β浓度更高(P < 0.05),表达CD86的细胞含量更多 (P < 0.05)。证实子宫自然杀伤细胞可以促进树突状细胞成熟,而树突状细胞促进子宫自然杀伤细胞的分泌,两者通过细胞间的直接接触而相互作用。     

具有梯度的流体切应力促进血管内皮细胞增殖

目的探讨流体切应力(shear stress,SS)对血管内支架边缘内皮细胞(endothelial cells,ECs)增殖的影响。方法应用具有切应力梯度的平行平板流动腔(梯度切应力组)和普通矩形平行平板流动腔(恒定切应力组),分别对ECs施加0.566￣1.438Pa和1.137Pa的切应力,加载时间6h,以未施加切应力的ECs为静止对照组。流式细胞仪检测各组ECs细胞周期的变化。结果梯度切应力组ECs在受力6h后进入S期与G2+M期细胞明显多于静止对照组与稳定切应力组(P<0.05);恒定切应力组的ECs受力后进入S期与G2+M期细胞明显少于其他两组(P<0.05)。结论梯度切应力促进ECs进入分裂增殖期,而稳定的层流切应力则产生对ECs细胞周期的抑制作用。提示血管内支架植入后,继发的血流切应力改变诱导细胞进入分裂、增殖期,这可能是引起支架内再狭窄过程中血管内膜增生的原因之一。     

用于内皮细胞与平滑肌细胞联合培养的流动腔系统

内皮细胞与平滑肌细胞的联合培养是体外研究这两种细胞生物学特性的重要手段。静态条件下联合培养的内皮细胞的形态及功能特性与在体条件下均有差异,这可能是没有血流切应力对内皮细胞直接作用的结果。为了了解切应力对与平滑肌细胞联合培养的内皮细胞的生物学作用,本文建立了用于多孔ＰＥＴ膜联合培养模型的力学系统,通过本系统可以产生０～４０ｄｙｎ／ｃｍ２的稳定层流切应力,并应用本系统观察了切应力对联合培养的内皮细胞的形态学影响,结果表明,在４０ｄｙｎ／ｃｍ２切应力作用下,与平滑肌细胞联合培养的内皮细胞沿流体方向发生了重排。这一系统的建立为研究切应力作用下与平滑肌细胞联合培养的内皮细胞的形态和功能提供了手段。     

Adhesion and Function of Human Endothelial Cells Co-cultured on Smooth Muscle Cells

To evaluate interactions between human endothelial cells (ECs) and smooth muscle cells (SMCs) for the development of tissue-engineered vessels, we examined the adhesion and key cell properties of human ECs grown on quiescent human aortic SMCs. ECs attached to SMCs spread more slowly than ECs attached to fibronectin surfaces, and ECs aligned along the direction of the SMCs. ECs attached firmly and less than 5% of the cells were removed by shear stresses as high as 300 dyn cm⁻². Unlike porcine SMCs and co-cultures, human SMCs or co-cultures do not contract under flow, and the human ECs and SMCs in co-culture align toward the direction of flow. A confluent endothelium could be maintained in co-culture for over 30 days, and some of the ECs reoriented perpendicular to the SMCs after 9 days in static culture. Surface tissue factor levels in ECs and SMCs were less in co-culture than in monoculture. Co-culture induced an increase in calponin expression in SMCs. These findings show that human co-cultures can be maintained for long culture periods, where the endothelium remains confluent and responds to long-term exposure to flow, and EC–SMC interactions lead to an increase in SMC differentiation and an EC surface that is less thrombotic.     

A system for the direct co-culture of endothelium on smooth muscle cells

The development of a functional, adherent endothelium is one of the major factors limiting the successful development of tissue engineered vascular grafts (TEVGs). The adhesion and function of endothelial cells (ECs) on smooth muscle cells (SMCs) are poorly understood. The goal of this research was to optimize conditions for the direct culture of endothelium on SMCs, and to develop an initial assessment of co-culture on EC function. The co-culture consisted of a culture substrate, a basal adhesion protein, a layer of porcine SMCs, a medial adhesion protein, and a layer of porcine ECs. Conditions that led to successful co-culture were: a polystyrene culture substrate, a quiescent state for SMCs, subconfluent density for SMC seeding and confluent density for EC seeding, and fibronectin (FN) for the basal adhesion protein. EC adhesion was not enhanced by addition of FN, collagen I, collagen IV or laminin (LN) to the medial layer. 3-D image reconstruction by confocal microscopy indicated that SMCs did not migrate over ECs and the cells were present in two distinct layers. Co-cultures could be consistently maintained for as long as 10 days. After exposure to 5 dyne/cm(2) for 7.5 h, ECs remained adherent to SMCs. PECAM staining indicated junction formation between ECs, but at a lower level than that observed with EC monocultures. Co-culturing ECs with SMCs did not change the growth rate of ECs, but EC DiI-Ac-LDL uptake was increased. Thus, a confluent and adherent layer of endothelium can be directly cultured on quiescent SMCs.     

Fluid flow mechanotransduction in vascular smooth muscle cells and fibroblasts

Understanding how vascular wall endothelial cells (ECs), smooth muscle cells (SMCs), and fibroblasts (FBs) sense and transduce the stimuli of hemodynamic forces (shear stress, cyclic strain, and hydrostatic pressure) into intracellular biochemical signals is critical to prevent vascular disease development and progression. ECs lining the vessel lumen directly sense alterations in blood flow shear stress and then communicate with medial SMCs and adventitial FBs to regulate vessel function and disease. Shear stress mechanotransduction in ECs has been extensively studied and reviewed. In the case of endothelial damage, blood flow shear stress may directly act on the superficial layer of SMCs and transmural interstitial flow may be elevated on medial SMCs and adventitial FBs. Therefore, it is also important to investigate direct shear effects on vascular SMCs as well as FBs. The work published in the last two decades has shown that shear stress and interstitial flow have significant influences on vascular SMCs and FBs. This review summarizes work that considered direct shear effects on SMCs and FBs and provides the first comprehensive overview of the underlying mechanisms that modulate SMC secretion, alignment, contraction, proliferation, apoptosis, differentiation, and migration in response to 2-dimensional (2D) laminar, pulsatile, and oscillating flow shear stresses and 3D interstitial flow. A mechanistic model of flow sensing by SMCs is also provided to elucidate possible mechanotransduction pathways through surface glycocalyx, integrins, membrane receptors, ion channels, and primary cilia. Understanding flow-mediated mechanotransduction in SMCs and FBs and the interplay with ECs should be helpful in exploring strategies to prevent flow-initiated atherosclerosis and neointima formation and has implications in vascular tissue engineering.     

Development of an Endothelial–Smooth Muscle Cell Coculture Model Using Phenotype-Controlled Smooth Muscle Cells

A coculture of endothelial cells (ECs) and smooth muscle cells (SMCs), which mimics cellular interactions appearing in vivo, has been performed in studies on the relationship between atherogenesis and fluid shear stress conditions. Although healthy arteries in vivo consist of contractile phenotype SMCs, cultured cells used in many studies normally exhibit a synthetic phenotype. Here, we developed an EC–SMC coculture model to investigate the interactions between ECs and contractile SMCs, and examined the effect of shear stress applied to ECs on SMC phenotypes. Cultured human umbilical artery SMCs were differentiated into contractile states by arresting cell growth using a serum-free medium. Western blotting confirmed that SMC expression of contractile protein markers, α-smooth muscle actin (SMA) and calponin, increased to levels similar to those observed in arterial cells. After coculturing contractile SMCs with ECs separated by a collagen gel layer, the expression of α-SMA decreased under static conditions, indicating that the SMC phenotype tended to be synthetic by coculturing with ECs, but shear stress applied to cocultured ECs maintained the level of α-SMA expression in SMCs. The coculture model constructed in the present study will be a useful tool to investigate interactions between ECs and contractile SMCs under shear conditions.     

A Dynamically Cultured Collagen/Cells-Incorporated Elastic Scaffold for Small-Diameter Vascular Grafts

Abstract

There is an essential demand for tissue-engineered autologous small-diameter vascular grafts, which offer temporary supports and guides for vascular tissue organization, repair and remodeling. This study reports on the effect of collagen/smooth muscle cells (SMCs) mixtures under dynamic cultures and SMC-endothelial cell (ECs) co-culture on cell proliferation, uniform cell distribution, extracellular matrix deposition, and endothelial cells monolayer formation in tissue-engineered tubular arterial constructs of 4 mm inner diameter. Rabbit aortic SMCs were infiltrated with collagen solution in poly(L-lactide-co-?-caprolactone) (PLCL) scaffolds under vacuum to form collagenous gel and subjected to dynamic strain by culturing them in a dynamic perfusion bioreactor. The construct lumen was subsequently seeded with ECs and experiments were completed to create ECs–SMCs co-culture constructs. The collagen/SMCs incorporated elastic scaffold cultured under dynamic culture conditions promoted matrix deposition, leading to the development of tissue-engineered vascular constructs, and induced SMC to have more uniform cell distribution. Scanning electron microscopic examination and von Willebrand Factor staining demonstrated the presence of ECs spread over the lumen. Quantitative analysis of elastin contents demonstrated that the engineered vessels acquired similar elastin contents as native arteries. The collagen/SMCs/ECs incorporated PLCL scaffolds under dynamic culture conditions can be used as a scaffold for tissue engineering to facilitate small-diameter vascular-tissue formation.     

Ultrastructure and molecular histology of rabbit hind-limb collateral artery growth (arteriogenesis)

Previous studies in the canine heart had shown that the growth of collateral arteries occurs via proliferative enlargement of pre-existing arteriolar connections (arteriogenesis). In the present study, we investigated the ultrastructure and molecular histology of growing and remodeling collateral arteries that develop after femoral artery occlusion in rabbits as a function of time from 2 h to 240 days after occlusion. Pre-existent arteriolar collaterals had a diameter of about 50 μm. They consisted of one to two layers of smooth muscle cells (SMCs) and were morphologically indistinguishable from normal arterioles. The stages of arteriogenesis consisted of arteriolar thinning, followed by transformation of SMCs from the contractile- into the proliferative- and synthetic phenotype. Endothelial cells (ECs) and SMCs proliferated, and SMCs migrated and formed a neo-intima. Intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) showed early upregulation in ECs, which was accompanied by accumulation of blood-derived macrophages. Mitosis of ECs and SMCs started about 24 h after occlusion, whereas adhesion molecule expression and monocyte adhesion occurred as early as 12 h after occlusion, suggesting a role of monocytes in vascular cell proliferation. Treatment of rabbits with the pro-inflammatory cytokine MCP-1 increased monocyte adhesion and accelerated vascular remodeling. In vitro shear-stress experiments in cultured ECs revealed an increased phosphorylation of the focal contacts after 30 min and induction of ICAM-1 and VCAM-1 expression between 2 h and 6 h after shear onset, suggesting that shear stress may be the initiating event. We conclude that the process of arteriogenesis, which leads to the positive remodeling of an arteriole into an artery up to 12 times its original size, can be modified by modulators of inflammation. Received: 16 March 1999 / Accepted: 4 August 1999     

造影红细胞对剪切流中肿瘤细胞黏附的影响

目的研究造影红细胞对剪切流环境中白细胞介导肿瘤细胞在内皮细胞上黏附的影响。方法在平行平板流动腔中加入20%比容的造影红细胞,分析不同剪切率(62.5、100、200 s-1)下内皮细胞上黏附白细胞数目、肿瘤细胞与黏附白细胞的碰撞事件以及稳定黏附肿瘤细胞数目的变化。结果造影红细胞促进白细胞在内皮细胞上黏附,增加肿瘤细胞与黏附白细胞的碰撞频率,并最终促进肿瘤细胞在内皮细胞上的黏附,且这一现象在高剪切率(200 s-1)下更为明显;但造影红细胞对肿瘤细胞的黏附效率并无显著影响。结论剪切流中造影红细胞的存在对肿瘤细胞在内皮细胞上的黏附起到促进作用,研究结果为探索癌症治疗方法提供理论基础。     

Gene response in endothelial cells cultured on engineered surfaces is regulated by shear stress

In vitro endothelialization of small-diameter synthetic vascular prostheses confluently lined with cultured autologous endothelial cells (ECs) before implantation has been shown to increase their patency. Many authors have studied the effects of shear stress on EC gene response seeded on various substrates showing different gene expression profiles according to cell type, flow times, or shear type with different molecular biology techniques, but few studies have reported any EC gene response to shear stress when cells are seeded on vascular grafts. The purpose of this in vitro study was to investigate whether ECs were able to transduce shear stress at the level of the nucleus. Human saphenous vein ECs were seeded on glass slides coated with gelatin or fibrin glue or on 6-mm fibrin-glue-coated grafts. Then cells were exposed to 12 dyn/cm(2) for 4 h and ribonucleic acid (RNA) were extracted. The relative messenger RNA (mRNA) expression was studied using real-time quantitative polymerase chain reaction for the following mRNAs: von Willebrand Factor, tissue-plasminogen activator, CD31, vascular endothelial (VE)-cadherin, beta(1) integrin, and vascular endothelial growth factor receptor type 2. From parallel flow chambers, results have shown similar EC gene response on gelatin and fibrin glue under laminar shear stress with downregulation of prothrombotic genes, as well as upregulation of nonthrombotic genes and upregulation of adhesion molecules such as VE-cadherin, but some discrepancies are noted, with a downregulation of CD31 and kinase insert domain receptor (KDR) for the former, without significant variation for the latter. In comparison, results show upregulation of tissue type plasminogen activator gene and downregulation of KDR, VE-cadherin, and beta(1) integrin genes in ECs lining grafts. To conclude, the major finding of our study is to show that human saphenous vein ECs seeded on fibrin glue (in planar flow chambers or in tubular grafts) can be regulated using shear stress via gene expression changes in a nonthrombotic way.