细胞骨架F-actin在层流剪切应力诱导EPCs内皮分化中的作用

目的探讨细胞骨架F-actin在层流剪切应力促内皮祖细胞(endothelial progenitor cells,EPCs)向内皮分化中的作用。方法对大鼠骨髓来源的EPCs施以层流剪切应力(1.2 Pa),以荧光定量RT-PCR及流式细胞术检测特异性内皮细胞标记分子vWF、CD31 mRNA及蛋白的表达来反映EPCs分化程度;以免疫荧光染色观测F-actin的排列情况;应用Ras GTPase Pull-Down方法检测Ras活性。结果层流剪切力处理后,EPCs分化标记vWF及CD31的基因及蛋白表达较静止组明显升高(P<0.05),细胞骨架F-actin发生重排,Ras活性明显增高。细胞骨架稳定剂Jasplakinolide(JAS)及细胞骨架松弛剂Cytochalasin D(CytoD)预处理均不同程度地抑制了层流剪切应力所致的细胞骨架的重排、Ras活性的上调及EPCs分化效应(P<0.05),而过表达Ras则对层流剪切应力诱导的EPCs分化有明显促进作用(P<0.05)。结论一定大小的层流剪切应力可促进EPCs向内皮细胞分化,其机制可能与层流剪切应力重塑细胞骨架F-actin,进而影响Ras活性有关;这对于揭示受损血管内皮修复的具体机制、阐明动脉粥样硬化等心血管疾病的发病机理及临床防治此类疾病具有一定的意义。     

神经胶质细胞对小鼠骨髓血管内皮前体细胞迁移的作用

目的 探讨视网膜神经胶质细胞对小鼠骨髓血管内皮前体细胞(EPCs)迁移的作用及可能机制.方法 荧光免疫激活流式细胞仪分选获得小鼠骨髓血管内皮前体细胞,分别用神经胶质细胞或对照组成纤维细胞作为条件共培养细胞与EPCs细胞共培养24 h后,检测内皮前体细胞通过孔隙的迁移数量;并用ELISA法检测培养液内VEGF及SDF一1的含量.结果 CD34/VEGFR2双标阳性的细胞为富含骨髓血管内皮前体细胞的细胞群,约占全部骨髓细胞的0.2%;当EPCs神经胶质细胞共培养24h后,EPCs通过孔隙的数量显著高于对照组与成纤维细胞共培养时通过的数量(上层存留细胞(20±16)个、vs(170±55)个,P<0.01).与神经胶质细胞共培养系统细胞培养液中VEGF及SDF～1含量显著高于对照组[VEGF:(230.28±27.37)pg/mL vs(89.22±11.23)pg/mL,P<0.01;SDF-1:(328.34±57.42)pg/mL vs(62.44±34.35)pg/mL,P<0.01].结论 神经胶质细胞可能通过细胞因子的分泌作用增强EPCs的移行,在EPCs参与的新生血管形成中可能有重要的介导作用.     

内皮祖细胞在血管新生及血管组织工程化过程中的生物学意义

内皮祖细胞(EPCs)是能分化为成熟血管内皮细胞的祖细胞,参与了出生后的血管再生和受损内皮的修复过程。近年来围绕以EPCs作为种子细胞来促进血管新生、维持内皮功能完整并构建组织工程化血管方面展开了许多研究。本文就这方面的进展作一综述。     

Endothelial progenitor cells homing to the orthotopic implanted liver tumor of nude mice

This study investigated the "homing" phenomenon in hepatocellular carcinoma (HCC).The "homing" specificity of endothelial progenitor cells (EPC) by establishing an orthotopic implantation model in nude mice.EPCs harvested from the marrow cells were separated by density gradient centrifugation.Fluorescence microscope,flow cytometry (FCM) and double fluorescence staining with FITC-UEA-I and DiI-ac-LDL,were employed to identify the cells.4’,6-diamidino-2-phenylindole (DAPI) labelling and real-time PCR were used for detecting the expression of CD133 and chemokines to trace and observe the distribution of EPCs.Our results showed that the distribution rate of EPCs was obviously higher than that in other important organs and the negative control group.Detection of CD133 and chemokines yielded similar results in difference tissues.Our experiment confirmed that the chemotaxis of EPCs does exist in HCC.Moreover,HIF-1α,SDF-1 and VEGF might play important roles in the "homing" of EPCs in HCC.EPCs might be a potential candidate for targeting vector of HCC for gene therapy.     

人脂肪组织来源内皮祖细胞的分离、培养及鉴定方法的实验研究

目的探讨人脂肪组织来源的内皮祖细胞的分离、培养及鉴定的方法。方法脂肪抽吸术获取人体脂肪组织,消化法得到的细胞接种在Fibronectin包被的培养皿内,用含2%胎牛血清的DMEM培养,传至第2代,分诱导组(EGM-2,2?S,VEGF,bFGF等)和非诱导组(DMEM,2?S)两组进行培养。免疫细胞荧光分别检测两组的CD34、vWF和PECAM-1表达;流式细胞仪分别检测两组的CD34、CD45、CD133和PECAM-1表达率;荧光显微镜观察细胞摄取DiI-ac-LDL的功能;诱导组细胞接种于甲基纤维素半固体培养基进行三维培养,观察血管样结构形成情况。结果诱导组细胞12d后呈现内皮细胞典型的铺路石样形态,未诱导组细胞未观察到这种变化;免疫细胞荧光显示诱导组vWF、PECAM-1表达阳性,未诱导组细胞CD34表达阳性;流式细胞仪检测显示诱导组PECAM-1阳性率为(67.41±13.35)%,明显高于非诱导组的(6.73±2.21)%(P<0.01),非诱导组CD34阳性率为(72.39±13.45)%,明显高于诱导组的(16.06±3.86)%(P<0.01);荧光显微镜观察显示诱导组细胞具有摄取DiI-ac-LDL的功能;诱导组细胞三维培养形成"树枝样"分叉结构。结论建立了一种从人脂肪组织分离、培养EPCs的方法,并对其表型进行鉴定,有望为血管组织工程提供新的种子细胞来源。     

Tumour vascularization: sprouting angiogenesis and beyond

Tumour angiogenesis is a fast growing domain in tumour biology. Many growth factors and mechanisms have been unravelled. For almost 30 years, the sprouting of new vessels out of existing ones was considered as an exclusive way of tumour vascularisation. However, over the last years several additional mechanisms have been identified. With the discovery of the contribution of intussusceptive angiogenesis, recruitment of endothelial progenitor cells, vessel co-option, vasculogenic mimicry and lymphangiogenesis to tumour growth, anti-tumour targeting strategies will be more complex than initially thought. This review highlights these processes and intervention as a potential application in cancer therapy. It is concluded that future anti-vascular therapies might be most beneficial when based on multimodal anti-angiogenic, anti-vasculogenic mimicry and anti-lymphangiogenic strategies.     

内皮祖细胞移植治疗慢性深静脉血栓形成的实验研究

目的 研究内皮祖细胞(endothelial progenitor cells,EPCs)移植对慢性深静脉血栓的治疗作用. 方法 Ficoll法分离大鼠骨髓单个核细胞(bone marrow-derived mononuclear cells,BMMNCs),采用内皮祖细胞培养基(EGM-2MV)诱导分化为骨髓源性EPCs.建立大鼠慢性深静脉血栓模型,饲养至10 d,并分三组:A组(25只):单纯EPCs组,移植1 ml含有10~6 个EPCs细胞悬液;B组(25只):EGM-2MV培养基对照组,移植1 ml EGM-2MV培养基;C组(25只):空白对照组.移植后第14天取出血栓段下腔静脉及血栓,应用HE染色及vWF免疫组化染色观察血栓机化再通情况,高倍镜下计数血栓内毛细血管数目;Western blot检测血管内皮生长凶子(VEGF)、碱性成纤维细胞生长因子(bFGF)的蛋白表达变化;实验数据采用SPSS13.0软件进行分析.结果 体外成功培养了骨髓源性EPCs和构建了大鼠慢性深静脉血栓模型,EPCs移植后A组VEGF、bFGF的表达有明显的上调(P＜0.05).B组和C组之间差异无统计学意义(P＞0.05).移植后A组血栓再通毛细血管数目明显高于B、C组.免疫组化染色vWF确定再通管道为新牛血管,管道为内皮细胞组成.结论 EPCs为内皮细胞的前体细胞,移植到深静脉血栓中能够促进血管新生,加快血栓的机化和再通.