微囊微环境体外扩增人脐血造血干/祖细胞

背景:由于单份脐血所含的造血细胞数量有限,目前只能用于儿童或低体质量成人血液病和急性辐射损伤等疾病患者,有效扩增脐血造血干,祖细胞已成为研究热点.目的:观察微囊微环境对脐血造血干,祖细胞扩增的影响,以及此过程中可否使造血干,祖细胞在扩增的同时仍维持其未分化状态.设计、时间及地点:单一样本观察,于2006-06/2007-09在中国科学院大连化学物理研究所完成.材料:正常足月产新生儿脐带血由大连市妇产医院提供,提供者知情同意.方法:Ficoll法梯度分离人脐血单个核细胞,采用静电液滴法在生理条件下进行微囊化包封和体外培养.以同条件平面培养的脐血单个核细胞作为对照.主要观察指标:观察微囊化脐血细胞的生长特点及脐血细胞总数的变化;流式细胞仪检测培养过程中CD34+细胞扩增情况:应用甲基纤维素半固体培养法观察扩增细胞的集落形成能力.结果:脐血细胞在微胶囊内持续增殖,并以聚集成团的三维方式生长,两种培养方式对脐血细胞总数均无明显影响(P>0.05).对比CD34+细胞扩增和细胞集落的生成发现,微囊化培养脐血细胞的CD34+细胞数量和集落密度均在培养第6天达到高峰,明显高于平面培养3 d时所达到的峰值:之后逐渐下降,至12 d后平面培养细胞的CD34+细胞和集落形成能力几乎检测不到,而此时微囊化培养的CD34+细胞数量和集落密度仍与平面培养的扩增高峰相近.结论:微囊化培养能有效扩增人脐血造血干/祖细胞,并显著减缓造血干/祖细胞的分化进程,维持其多分化潜能,提示微囊为造血干/祖细胞维持未分化状态的扩增提供了特殊的微环境.     

脐血间充质干细胞的生物学特征及其对造血干/祖细胞体外扩增的支持作用

目的探讨脐血间充质干细胞(MSC)的生物学特征及其对造血干/祖细胞体外扩增的支持作用。方法用液体培养法分离脐血贴壁细胞,采用ELISA方法检测贴壁细胞条件培养液中细胞因子的表达;用流式细胞术分析其免疫表型特征;在成软骨细胞诱导培养条件下诱导细胞分化,并用RTPCR方法检测分化后细胞原胶原Ⅱ型基因的表达。采用分阶段共培养方法观察脐血贴壁细胞对CD34+细胞体外扩增的支持作用。结果脐血单个核细胞纤维样细胞集落形成率为(3.5±0.7)/106。脐血MSC体外至少可以扩增15代。没有分化的脐血MSC表型为CD13、CD29、CD90、CD105、CD166、SH2、SH3和SH4阳性,CD45、CD34和CD14阴性;脐血MSC培养上清中干细胞因子、IL6和肿瘤坏死因子α检测阳性。在成软骨细胞诱导培养基培养条件下,脐血MSC原胶原Ⅱ型基因mRNA表达阳性。脐血MSC与CD34+细胞共掊养14d,CD34+细胞扩增率高于未共培养组4倍。结论脐血MSC具有类似于成体骨髓MSC的特征,对造血干细胞增殖有明显的支持作用。     

造血干细胞移植后患者间充质干细胞增殖功能的研究

为了研究造血干细胞移植（hematopoietic stem cell transplantation,HSCT）后造血植活患者中骨髓源的间充质干细胞（mesenchymal stem cells,MSCs）的增殖能力,本研究选择造血干细胞移植后临床植活的34例患者作为研究对象,抽取34例患者及30例正常健康供者骨髓,进行微环境成纤维细胞集落形成单位（colony-formingunit-fibroblast,CFU-F）集落培养,同时对MSC进行培养传代,记录MSC的融合时间及传代总数;利用流式细胞术（flowcytometry,FCM）检测患者MSC表面抗原的表达;将此34例患者培养结果与30例正常对照结果进行比较统计。另外对其中骨髓加外周血加第二供者脐血移植的10例患者与骨髓加外周血移植的19例患者的MSC体外扩增指标进行比较统计。结果表明：34例患者中有31例（91.1%）患者的MSC原代培养能达到贴壁融合,有1例（2.9%）达到部分融合,2例（5.9）未达融合;与正常对照相比,患者的MSCs融合时间明显延长,传代总数明显减少,CFU-F数明显降低,即其MSC的体外扩增能力明显受损。骨髓加外周血加第二供者脐血移植的10例患者与骨髓加外周血移植的19例患者相比,MSC达到融合的时间短,体外传代总数多,CFU-F计数高。结论：移植后患者的MSC呈明显受损状态,加用第二供者脐血细胞能部分改善患者MSC体外增殖功能。     

磁力搅拌悬浮培养大规模扩增脐血造血祖细胞

为了利用磁力搅拌悬浮培养装置大规模体外扩增脐血造血祖细胞，从脐血分离单个核细胞，以无血清培养基stemspan添加干细胞因子、FLT-3配基及血小板生成素为培养体系进行培养。先研究磁场（25和50mT）对静态扩增培养的造血祖细胞生长和集落形成能力的影响，再研究磁力搅拌悬浮大规模培养对造血细胞总数扩增、造血集落形成和表面分子标志表达变化。结果表明，在0，25和50mT磁场组和磁转子组，细胞总数扩增倍数和造血集落形成数在各组间均无明显区别（P〉0．05）。经过7天的扩增培养，磁力搅拌悬浮大规模培养细胞总数扩增倍数为2．8±0．45，高于静态培养细胞总数扩增倍数（2．1±0．48）（P〈0．01）；磁力搅拌悬浮培养组形成的红系集落数（1983．5±582．6）、粒-巨噬细胞集落数（186．4±62．7）明显高于静态培养形成的相应的造血集落数（分别为1396．2±425．7和136．5±40．8）（P均〈0．05）：磁力搅拌悬浮扩增后造血干细胞（CD34^＋、CD34^＋／CD38^-或CD133^＋）比例分别为（0.9±0．34）％、（0．7±0．21）％和（1．1±0．35）％，低于静态培养的干细胞比例[分别为（1．4±0．35）％、（1．2±0．34）％和（1．6±0．68％）]（P均〈0．05）；但是，归巢相关分子CD184和CD62L高于静态扩增培养．．结论：磁力搅拌悬浮装置可能有利于脐血造血祖细胞规模扩增，本研究结果还有待于动物实验及临床移植试验进一步验证.     

转白血病抑制因子基因人胚肺成纤维细胞对脐血CD34+细胞体外扩增的影响

背景:单份脐血的造血细胞数量有限,难以满足成人的需要,如何有效地扩增脐血造血干/祖细胞是目前研究的热点.目的:构建人白血病抑制因子基因修饰的人胚肺成纤维细胞,观察转基因细胞对脐血CD34+造血干/祖细胞体外扩增的影响.方法:建立转人白血病抑制因子基因的饲养层细胞,用RT-PCR法和ELISA法鉴定目的基因的表达;采用免疫磁珠法分离脐血CD34+造血干/祖细胞,流式细胞术检测纯度;将CD34+造血干/祖细胞与饲养层细胞共培养,流式细胞术检测各组增殖效果;扩增后的造血干/祖细胞用跨膜迁移实验检测自发迁移率和基质细胞衍生因子1诱导迁移试验以鉴定体外扩增的造血干/祖细胞的归巢能力.结果与结论:成功建立转基因饲养层细胞,RT-PCR法和ELISA法证实有目的基因表达,与人白血病抑制因子转基因饲养层细胞共培养7 d后CD34+造血干/祖细胞可大量扩增,同时表面黏附分子的表达量仍较高.体外迁移实验显示与转基因饲养层细胞共培养的造血细胞的诱导迁移率明显高于对照组,可以较好地保持其归巢能力.因此转人白血病抑制因子基因的饲养层细胞可有效扩增脐血CD34+造血干/祖细胞,延缓其分化,并且体外扩增后仍保持较高的归巢能力.     

转白血病抑制因子基因人胚肺成纤维细胞对脐血CD34~＋细胞体外扩增的影响

背景：单份脐血的造血细胞数量有限,难以满足成人的需要,如何有效地扩增脐血造血干/祖细胞是目前研究的热点。目的：构建人白血病抑制因子基因修饰的人胚肺成纤维细胞,观察转基因细胞对脐血CD34＋造血干/祖细胞体外扩增的影响。方法：建立转人白血病抑制因子基因的饲养层细胞,用RT-PCR法和ELISA法鉴定目的基因的表达;采用免疫磁珠法分离脐血CD34＋造血干/祖细胞,流式细胞术检测纯度;将CD34＋造血干/祖细胞与饲养层细胞共培养,流式细胞术检测各组增殖效果;扩增后的造血干/祖细胞用跨膜迁移实验检测自发迁移率和基质细胞衍生因子1诱导迁移试验以鉴定体外扩增的造血干/祖细胞的归巢能力。结果与结论：成功建立转基因饲养层细胞,RT-PCR法和ELISA法证实有目的基因表达,与人白血病抑制因子转基因饲养层细胞共培养7d后CD34＋造血干/祖细胞可大量扩增,同时表面黏附分子的表达量仍较高。体外迁移实验显示与转基因饲养层细胞共培养的造血细胞的诱导迁移率明显高于对照组,可以较好地保持其归巢能力。因此转人白血病抑制因子基因的饲养层细胞可有效扩增脐血CD34＋造血干/祖细胞,延缓其分化,并且体外扩增后仍保持较高的归巢能力。     

体外诱导人类诱导性多能干细胞分化为造血干 / 祖细胞的研究简

本研究探讨体外诱导人诱导性多能干细胞（induced pluripotent stem cell,iPSC）分化为造血干/祖细胞的能力.在体外用小鼠骨髓基质细胞OP9与人类iPSC共培养的方法,将iPSC诱导分化为造血干/祖细胞;用流式细胞术检测造血干/祖细胞表面标志物的表达水平;用实时定量PCR检测分化过程中iPSC及造血干/祖细胞的相关基因mRNA表达水平的变化;用免疫磁珠法分离CD34＋造血干/祖细胞并进行半固体集落形成实验检测细胞的集落形成能力.结果表明,iPSC与OP9细胞共培养诱导造血分化的第4天即可观察到iPSC形态变化;流式细胞术检测显示,分化得到的细胞表达已知的造血干/祖细胞相关表面标志物CD34和CD43分子.在体外分化过程中多能性的标志基因Oct4的表达逐渐下降,造血相关转录因子Gata-2的表达逐渐升高,而Runx-1的表达量则呈波浪式变化,CD34表达量逐渐升高.集落培养14 d能够得到红系集落（CFU-E）,粒系集落（CFU-G）,巨核系集落（CFU-M）,粒-巨核系集落（CFU-GM）和混合系集落（CFU-GEMM）.结论：iPSC细胞能够在体外通过与OP9细胞共培养分化为造血干/祖细胞.     

脐血单个核细胞与骨髓间充质干细胞滋养层的共培养

背景:骨髓间充质干细胞具有维持骨髓正常造血功能,在造血调控中发挥重要的作用。目的:观察骨髓间充质干细胞的生物学性状和多向分化能力,并检测其在体外支持造血的能力。方法:利用密度梯度培养法分离骨髓单个核细胞进行培养,流式细胞仪检测骨髓间充质干细胞表型;接种脐血单个核细胞于骨髓间充质干细胞滋养层培养板上共培养,观察粒-单系祖细胞集落变化。结果与结论:骨髓间充质干细胞呈典型的成纤维样细胞形态,强表达CD44,CD29,不表达CD34和CD106。可促进脐血单个核细胞扩增并形成造血祖细胞集落。提示骨髓间充质干细具有造血支持作用。     

间充质干细胞对脐血CD34^＋细胞扩增及其细胞特性变化的影响

本研究探讨脐带间充质干细胞（MSC）对CD34^＋细胞（HSPC）体外扩增的支持作用及对CD34^＋细胞表面标志、归巢黏附分子、集落形成能力等干细胞特征变化的影响。用免疫磁珠法从新鲜分离的脐血单个核细胞分离CD34^＋造血干祖细胞（HSPC）；用MSC饲养层（feeder）制备经^137Cs照射的间充质干细胞饲养细胞（MSC feeder cells）。将CD34^＋细胞接种在不同的培养体系中，实验分为3组：HSPC＋CK组为培养液中加入细胞因子组合（SCF、FL和TPO），HSPC＋MSC组为CD34^＋细胞接种在MSC feeder上，HSPC＋MSC＋CK组同时加入细胞因子组合及MSC饲养细胞。培养后4、7、10、14天计数有核细胞总数（MNC），计算细胞扩增情况；用流式细胞术检测不同处理组间CD34^＋细胞及亚群免疫表型、归巢黏附分子和集落形成能力。结果表明：在2周的培养时间里，3组MNC和CD34^＋细胞均明显增加，MNC扩增数依次HSPC＋MSC＋CK组〉HSPC＋CK组〉HSPC＋MSC组。体外扩增10天内HSPC＋MSC＋CK组MNC得到大量的扩增，同时CD34^＋细胞的扩增亦较高。培养4天3组细胞CD34^＋比例较0天有明显下降（P〈0．01）；扩增后CD34^＋细胞比例：HSPC＋MSC组〉HSPC＋MSC＋CK组〉HSPC＋CK组（P〈0．01）；各组CD34^＋细胞亚型细胞比例有所不同，HSPC＋CK组4天时CD34^＋CD38^-细胞有一过性升高（62．71％），之后迅速降低，7天时为0．05％；HSPC＋MSC组7天时CD34^＋CD38^-细胞比例为18．92％，与HSPC＋CK组比较差异有统计学意义（P〈0．05）。从集落形成分析结果看出：MSC、细胞因子混合组扩增后细胞集落形成能力在不同时间点均维持在较高水平。结论：脐血CD34^＋细胞在体外短期培养（〈7天）下，MSC和细胞因子联合应用能同时使CD34^＋细胞得到明显的扩增并维持造血干祖细胞的生物学特征。     

脐血造血干／祖细胞研究进展

脐血和骨髓均富含造血干／祖细胞，但二者在造血干／祖细胞的含量上存在差别。脐血中各CD34^ 细胞亚群有着独特的免疫表型。脐血造血干／祖细胞能在体外扩增，扩增后的CD34^ 细胞能在SCID小鼠体内造血，由脐血CD34^ 细胞可以生成淋巴细胞和内皮细胞。脐血造血干／祖细胞移植与骨髓造血干／祖细胞移植在患者的生存率、复发率及移植免疫排斥等方面均具有可比性，有着极大的潜在价值。     

Co-cultivation of progenitor cells enhanced osteogenic gene expression and angiogenesis potential in vitro

ObjectivesThe efficiencies of osteogenesis and angiogenesis present challenges that need to be overcome before bone tissue engineering can be widely applied to clinical uses. We aimed to optimize an in vitro culture system to enhance osteogenesis and angiogenesis. We investigated if hematopoietic stem cells (HSCs) promoted osteogenesis in vitro when co-cultured with mesenchymal stem cells (MSCs) and endothelial progenitor cells (EPCs).MethodsMSC/HSC, MSC/EPC/HSC, and MSC/EPC co-cultures were incubated for 21 days. Alkaline phosphatase (ALP) activity and calcium content were analyzed to assess mineralization. Expression levels of genes encoding osteogenesis-related proteins (ALP (ALPL), collagen type IA (COL1A1), osteocalcin (BGLAP), and osteopontin (OSTP)) were also evaluated by measuring mRNA levels at day 28. Angiogenesis was evaluated by tube-formation assay.ResultsCOL1A1, OSTP, ALPL, and BGLAP genes were upregulated in MSC/HSC and MSC/EPC/HSC co-cultures compared with the MSC/EPC group. Upregulation was strongest in the MSC/EPC/HSC co-cultures. There were no significant changes in ALP levels and calcium content, but ALP activity was slightly higher and calcium content was relatively lower in the MSC/EPC and MSC/EPC/HSC groups.ConclusionsCo-culture of MSCs with HSCs or EPCs/HSCs upregulated the expression of osteogenesis-related genes but did not affect the efficiency of osteogenesis.     

体外扩增小鼠造血干/祖细胞及重建造血功能的研究

目的 探讨体内中性粒细胞的快速植入及长期重建造血的能力。方法 分离经氟尿嘧啶处理的雄性BDF1小鼠骨髓单个核细胞，以MoFlo细胞分选系统分离纯化CD34^ /c-kit^ 造血干，祖细胞，体外应用骨髓间充质干细胞共培养和阶段扩增结合的方法分别对分离的单个核细胞和CD34^ /c-kit^ 细胞进行体外扩增，并将扩增的有核细胞移植给经亚致死剂量照射的雌性小鼠。结果 以骨髓间充质干细胞为培养基质细胞，结合分阶段扩增方法，有效提高了各种细胞的扩增倍数，其中单个核细胞扩增的总有核细胞、CD34^ 细胞、GM-CFC和HPP-CFC扩增倍数分别为10．8，4．8，65．9和38．8，CD34^ /c-kit^ 细胞扩增的以上4种细胞扩增倍数分别为76．1，2．9，71．7和51．8；扩增细胞移植后可快速产生体内中性粒细胞的植入，并在2个月后的移植小鼠中仍可检测到移植的造血细胞。结论 与骨髓间充质干细胞的共培养，为造血干，祖细胞的有效扩增提供了良好的环境，分阶段扩增法加快了体外造血干，祖细胞的扩增和成熟，为移植后体内中性粒细胞的快速植入创造了条件。     

骨髓间充质干细胞分化的成骨细胞支持脐血造血干祖细胞的研究

本研究利用骨髓间充质干细胞诱导分化的成骨细胞构建二维培养体系,探讨其体外支持脐血干/祖细胞生存的作用.体外进行人骨髓间充质干细胞（MSC）原代培养后诱导为成骨细胞,构建二维培养体系.将免疫磁珠分选的CD34^＋脐血干/祖细胞接种于其中,在无外源性细胞因子情况下进行体外培养,进行CFU,HPP-CFU和LTC-IC测定并将其分别与MSC、成骨细胞,MSC/成骨细胞（1：2）作为饲养细胞的二维培养体系实验结果相比较.结果发现：在所构建的造血干/祖细胞（HSPC）二维培养体系中,骨髓MSC诱导成骨细胞对于脐血造血干/祖细胞培养的支持作用显著优于其他各组培养体系,尤其对长期造血干细胞（long term-HSC）体外生存有更为明显地支持作用.结论：骨髓间充质干细胞诱导成骨细胞构建的二维体系对于脐血干/祖细胞体外培养具有支持作用,进一步证实成骨细胞对造血干细胞生存与增殖具有重要调控作用.     

间充质干细胞对脐血CD34+细胞体外扩增和黏附分子表达的影响

目的研究间充质干细胞(MSC)对脐血CD34+细胞体外扩增能力和黏附分子表达的影响.方法从正常人骨髓中分离扩增MSC,通过免疫表型和向成骨细胞及脂肪细胞分化能力对其鉴定;将脐血CD34+细胞接种到MSC或其他培养液中,比较不同培养条件对造血细胞扩增能力、集落形成能力及黏附分子表达的影响.结果MSC表达Thy-1、SH2、SB10、CD44、CD13、CD49e和CD29,不表达CD34、CD45、HLA-DR、CD14和CD31,经过诱导可以向成骨细胞和脂肪细胞分化;实验组在MSC和细胞因子作用下,扩增8 d后有核细胞、CD34+、CD34+CD38-、CD34+CD62L+细胞和CFU-Cs分别扩增145.57±17.89,37.47±13.78,69.78±50.07,10.74±5.89和20.73±5.54倍,均显著高于对照组;扩增后CD34+细胞的ALCAM、VLA-α4、VLA-α5、VLA-β1、HCAM、PECAM和LFA-1表达较扩增前无明显变化,虽然ICAM-1和L-选择素表达下降,但实验组CD34+CD62L+和CD34+CD54+细胞的绝对数显著增加.结论MSC可为造血干细胞体外扩增提供适宜的微环境,有助于抑制HSC分化并保持其造血重建潜能和归巢能力.     

Mesenchymal stem cells from CD34− human umbilical cord blood

Umbilical cord blood (UCB) is well known to be a rich source of stem cells especially for haematopoietic stem cells (HSCs). Recently, mesenchymal stem cells (MSCs) have also been shown to exist in cord blood. Although MSCs have been described by a subset of surface antigens after expansion, little is known about the cell surface phenotype of undifferentiated MSCs. The aim of this study therefore was to clarify whether undifferentiated MSCs are resident among CD34^? UCB cells. CD34⁺ cells were separated from UCB mononuclear cells (MNCs) by magnetic sorting and the CD34^? cell fractions were cultured in Dulbecco's modified Eagle's medium (DMEM) with 10% foetal calf serum (FCS) and basic‐fibroblast growth factor. Isolated CD34⁺ cells were also cultured in the same medium. Adherent fibroblast‐like cells at passage 3–4 were analyzed by fluorescence‐activated cell sorting (FACS) for MSC marker expression , and standard adipogenic, osteogenic and chondrogenic assays were used to investigate their differentiation potentials. After 4–5 weeks in culture, the cells from the CD34^? fraction became confluent with flat and fibroblast‐like morphology. These cells were positively stained for the mesenchymal cell markers CD29, CD73 and CD105. In adipogenic differentiation, the cells showed oil red O positive and expressed FABP4, adipsin and proliferation‐activated receptor γ‐2 (PPARγ2 genes) associated with adipogenesis. In osteogenic differentiation, calcium accumulation and osteocalcin were detected. The cells grown in chondrogenic conditions were positively stained for human aggrecan and expressed collagen type II and Sox‐9 genes. In contrast, cells from the CD34⁺ fraction failed to generate any cells with MSC morphology under the same culture conditions. Our results showed that UCB contained MSCs which are only resident in the CD34^? fraction. The MSCs could be induced to differentiate into at least three lineage cell types, adipocytes, osteoblasts and chondrocytes.     

Dynamic cell–cell interactions between cord blood haematopoietic progenitors and the cellular niche are essential for the expansion of CD34+, CD34+CD38− and early lymphoid CD7+ cells

Most clinical applications of haematopoietic stem/progenitor cells (HSCs) would benefit from their ex vivo expansion to obtain a therapeutically significant amount of cells from the available donor samples. We studied the impact of cellular interactions between umbilical cord blood (UCB) haematopoietic cells and bone marrow (BM)‐derived mesenchymal stem cells (MSCs) on the ex vivo expansion and differentiative potential of UCB CD34⁺‐enriched cells. UCB cells were cultured: (a) directly in contact with BM MSC‐derived stromal layers (contact); (b) separated by a microporous membrane (non‐contact); or (c) without stroma (no stroma). Highly dynamic culture events occurred in HSC‐MSC co‐cultures, involving cell–cell interactions, which preceded HSC expansion. Throughout the time in culture [18 days], total cell expansion was significantly higher in contact (fold increase of 280 ± 37 at day 18) compared to non‐contact (85 ± 25). No significant cell expansion was observed in stroma‐free cultures. CD34⁺ cell expansion was also clearly favoured by direct contact with BM MSCs (35 ± 5‐ and 7 ± 3‐fold increases at day 18 for contact and non‐contact, respectively). Moreover, a higher percentage of CD34⁺CD38^? cells was consistently maintained during the time in culture under contact (8.1 ± 1.9% at day 18) compared to non‐contact (5.7 ± 1.6%). Importantly, direct cell interaction with BM MSCs significantly enhanced the expansion of early lymphoid CD7⁺ cells, yielding considerably higher (×3–10) progenitor numbers compared to non‐contact conditions. These results highlight the importance of dynamic cell–cell interactions between UCB HSCs and BM MSCs, towards the maximization of HSC expansion ex vivo to obtain clinically relevant cell numbers for multiple settings, such as BM transplantation or somatic cell gene therapy. Copyright © 2009 John Wiley & Sons, Ltd.     

Granulocyte colony‐stimulating factor (G‐CSF) depresses angiogenesis in vivo and in vitro: implications for sourcing cells for vascular regeneration therapy

Summary. Background: The most common source of hematopoietic progenitor cells (HPCs) for hematopoietic reconstitution comprises granulocyte colony‐stimulating factor (G‐CSF)‐mobilized peripheral blood stem cells (PBSCs). It has been proposed that endothelial progenitor cells (EPCs) share precursors with HPCs, and that EPC release may accompany HPC mobilization to the circulation following G‐CSF administration. Objective: To investigate EPC activity following HPC mobilization, and the direct effects of exogenous G‐CSF administration on human umbilical vein endothelial cells (HUVECs) and endothelial outgrowth cells (EOCs), using in vitro and in vivo correlates of angiogenesis. Patients/Methods: Heparinized venous blood samples were collected from healthy volunteers and from cord blood at parturition. G‐CSF‐mobilized samples were collected before administration, at apheresis harvest, and at follow‐up. PBSCs were phenotyped by flow cytometry, and cultured in standard colony‐forming unit (CFU)‐EPC and EOC assays. The effect of exogenous G‐CSF was investigated by addition of it to HUVECs and EOCs in standard tubule formation and aortic ring assays, and in an in vivo sponge implantation model. Results: Our data show that G‐CSF mobilization of PBSCs produces a profound, reversible depression of circulating CFU‐EPCs. Furthermore, G‐CSF administration did not mobilize CD34+CD133? cells, which include precursors of EOCs. No EOCs were cultured from any mobilized PBSCs studied. Exogenous G‐CSF inhibited CFU‐EPC generation, HUVEC and EOC tubule formation, microvessel outgrowth, and implanted sponge vascularization in mice. Conclusions: G‐CSF administration depresses both endothelial cell angiogenesis and monocyte proangiogenic activity, and we suggest that any angiogenic benefit observed following implantation of cells mobilized by G‐CSF may come only from a paracrine effect from HPCs.     

Fn、TPO基因修饰对人骨髓间充质干细胞的影响

目的 观察纤维连接蛋白(Fn)、血小板生成素(TPO)融合基因修饰对人骨髓间充质干细胞(MSC)的影响.方法 构建携带Fn-TPO融合基因的重组逆转录病毒载体,并以其对骨髓MSC进行基因修饰;观察Fn-TPO基因在骨髓MSC中的表达,以及基因修饰后骨髓MSC的体外增殖、黏附造血细胞和分泌TPO的能力;并将脐血CD34+细胞接种到基因修饰后骨髓MSC形成的滋养层,培养7d观察修饰后骨髓MSC对造血细胞体外扩增和集落形成能力的影响.结果 成功构建携带Fn-TPO基因的重组逆转录病毒载体且以该逆转录病毒载体对骨髓MSC进行体外基因修饰;Fn、TPO基因在骨髓MSC内能够正常转录;基因修饰后的骨髓MSC体外增殖能力[(6.92±0.77)×104/ml]与对照组[(7.18±0.89)×104/ml]比较差异无统计学意义(P＞0.05);基因修饰组和对照组黏附造血细胞能力分别为0.188±0.018和0.167±0.017(P＜0.01),分泌TPO能力分别为(7.46±0.59)ng/ml和(5.58±0.37)ng/ml(P＜0.01),细胞分泌TPO的能力不受培养时间的影响,但受细胞生长状态影响;2×104脐血CD34+造血干/祖细胞经基因修饰后骨髓MSC联合必要细胞因子体外扩增7 d,有核细胞数、CD34+细胞比例、BFU-E、CFU-GM及CFU-GEMM分别为(29.9±2.7)×104、(33.3±2.8)%、109.3±4.1/1×104CD34+细胞、163.7±7.1/1×104CD34+细胞、13.3±1.5/1×104CD34+细胞,较对照组明显增加(P＜0.01).结论 Fn-TPO基因修饰能够增强骨髓MSC黏附造血细胞、分泌TPO及支持脐血CD34+细胞扩增的能力.