微载体技术高密度培养MRC-5细胞初探

目的 通过探索MRC-5细胞的微载体培养条件,以期建立MRC-5细胞的高密度培养方法.方法 用3种不同培养基（MEM、M199、DMEM）分别培养3.0×104/mL的MRC-5细胞,观察它们的细胞增殖及传代能力;在Spinner培养系统中,用1.0 g/L Cytopore 2和3.0 g/L Cytodex 3分别培养密度为3.70× 105/mL和2.98×105/mL的MRC-5细胞,观察两种载体对细胞生长代谢和细胞密度的影响,筛选出最适宜的培养基及微载体.使用5 L CelliGen310生物反应器对筛选获得的培养基及微载体进行MRC-5细胞的灌流培养初步摸索.结果 MRC-5细胞在MEM、M199、DMEM培养基中培养96 h细胞分别增殖了7.0、4.4和3.0倍;在MEM培养基中连续传代至5次以上,细胞增殖稳定,1：3传代72 h形成致密单层,而在M199和DMEM培养基中连续传代均未能获得理想的细胞形态.经96～120 h的培养后,使用1.0 g/L Cytopore 2培养的MRC-5细胞密度达到2.20× 106/mL高于使用3.0 g/L Cytodex 3的1.12×106/mL,且前者葡萄糖和乳酸代谢较后者更为活跃.首选MEM和Cytopore 2作为MRC-5细胞的灌流培养体系.在5L生物反应器中以1.0 g/L Cytopore 2和2.5LMEM培养基培养MRC-5细胞至144h,细胞密度达到1.54×106/mL.结论 初步建立的MEM Cytopore 2微载体细胞培养方法能够获得高密度、活性良好的MRC-5传代细胞.     

冷冻胚胎经序贯共培养用于建立人胚胎干细胞系

目的:利用长期冷冻人卵裂期胚胎经序贯共培养形成的囊胚建立人类胚胎干细胞系。方法:将冷冻≥10年的卵裂期胚胎复苏后,采用单层卵丘细胞序贯共培养至囊胚期,经辅助孵出,置鼠胚胎成纤维细胞(MEF)饲养层全胚培养,原代培养6d后加入20%MEF条件培养基培养至形成原代克隆。观察人胚胎干细胞集落的生长状态并通过碱性磷酸酶染色、Oct-4基因表达、核型分析及体外分化实验等方法进行生物学鉴定。结果:9枚冷冻卵裂期胚胎经序贯共培养,有6枚发育到囊胚期,最终获得1株胚胎干细胞系。经鉴定该细胞系具有碱性磷酸酶活性、表达Oct-4胚胎干细胞特异标记、形成拟胚体、在体外形成具有自动节律性的心肌细胞、并具有46,XY核型等5种特性。结论:冷冻胚胎经序贯共培养能够改善胚胎发育潜能,有助于建立人胚胎干细胞系。     

人胚胎干细胞培养体系的研究进展

人胚胎干细胞(hES细胞)是来源于着床前人囊胚内细胞团的、具有自我更新能力和分化全能性的细胞。由于具有体外无限增殖和分化成三个胚层来源的各种细胞的潜能,hES细胞具有重要的科学意义和巨大的医学应用价值。目前,hES细胞常规体外培养技术多采用培养基与饲养层相结合的方法,但常规方法存在异源病原体污染的可能。近年来,优化hES细胞体外培养体系的研究取得较大进展,现就饲养层、无饲养层培养体系进行综述,分析目前在维持hES细胞未分化状态的优化培养研究中取得的新进展和存在的问题。     

人胚胎干细胞培养体系的研究进展

人胚胎干细胞(hES细胞)是来源于着床前人囊胚内细胞团的、具有自我更新能力和分化全能性的细胞.由于具有体外无限增殖和分化成三个胚层来源的各种细胞的潜能,hES细胞具有重要的科学意义和巨大的医学应用价值.目前,hES细胞常规体外培养技术多采用培养基与饲养层相结合的方法,但常规方法存在异源病原体污染的可能.近年来,优化hES细胞体外培养体系的研究取得较大进展,现就饲养层、无饲养层培养体系进行综述,分析目前在维持hES细胞未分化状态的优化培养研究中取得的新进展和存在的问题.     

诱导人胚胎干细胞向子宫内膜样细胞分化的初步研究

目的:探讨无饲养层培养的人胚胎干细胞诱导分化为子宫内膜样细胞的方法。方法:将无饲养层培养的人胚胎干细胞分别通过共培养诱导法和细胞因子诱导法向子宫内膜样细胞诱导,流式细胞术检测分化的细胞中子宫内膜上皮细胞标志物细胞角蛋白18和间质细胞标志物波形蛋白的表达情况。结果:共培养诱导法和细胞因子诱导法在分化第7天均出现长梭状细胞样改变。分化第8天通过流式细胞术检测发现细胞波形蛋白表达均为阴性,部分细胞角蛋白18表达阳性,共培养诱导法分化率高于细胞因子诱导法[(55.63±10.29)%vs.(13.90±0.26)%,P<0.05]。结论:共培养诱导法和细胞因子诱导法均可使人胚胎干细胞分化为子宫内膜上皮样细胞,但前者的分化效率更高。     

恒河猴精原干细胞的筛选、培养与鉴定

目的:建立恒河猴精原干细胞的筛选和培养方法。方法:采用改良的二步酶消化法分离恒河猴睾丸细胞,用改进的差异贴壁筛选法纯化恒河猴精原干细胞,用添加了胶质细胞源神经营养因子(GDNF)、可溶性GFRα1和bFGF的DMEM/F12无血清培养基和小鼠胚胎成纤维细胞饲养层培养恒河猴精原干细胞,并通过形态观察、标志基因的免疫细胞化学分析和半定量RT-PCR分析鉴定培养细胞的干细胞活性。结果:分离纯化的恒河猴精原干细胞在添加了3种生长因子的培养基中能形成较大的干细胞克隆,并表达精原干细胞的标志基因。结论:本研究初步建立了恒河猴精原干细胞的培养体系,为进一步开展相关研究奠定基础。     

大鼠脂肪源性干细胞分离培养的实验研究

目的研究分离、培养、鉴定大鼠脂肪源性干细胞的实验方法。方法提取大鼠双侧腹股沟处脂肪组织,进行原代培养及流式细胞检测仪的鉴定。用MTT法检测不同原代细胞接种密度的细胞分裂增殖率的变化,并观察第1^第13代细胞分裂增殖的特点。结果大鼠脂肪源性干细胞的生长呈大量细胞集落,表面标记物CD44、CD105、CD49d表达阳性,CD106表达阴性。不同的原代细胞接种密度会影响细胞分裂增殖,以1×106/ml细胞密度接种时细胞的增殖速率高于其它对照组。该细胞株经多次传代后仍能保持较强的分裂增殖能力。结论大鼠脂肪源性干细胞分离培养方法简便,不同的原代细胞接种密度会影响细胞分裂增殖,细胞经多次传代后仍能保持较强的分裂增殖能力。     

环氧乙烷薰蒸污染炭疽杆菌粮食的效果观察

目的观察用环氧乙烷熏蒸处理炭疽杆菌污染的粮食135.5万公斤的效果.方法采用1.5cm2八层纱布浸润枯草杆菌黑色变种芽胞菌液作为指标菌.土圆仓按2m3分上、中、下三层各放菌数不同5个平行样(5×104、1×105、5×105、2.5×106、5×106cfu/0.1ml)和袋装粮堆每2～5袋间放5×106cfu/ml菌片一张.环氧乙烷用量为土园仓250g/m3,袋装粮堆700g/ma.结果通风除去环氧乙烷6h后取出菌片培养观察转阴数,结果转阴率达96%以上,薰蒸粮食食用后未发现异常情况.结论初步认为用环氧乙烷薰蒸处理炭疽杆菌污染的粮食是可行的.     

昆明鼠胚胎干细胞系建立中原代克隆生长及其传代方法的研究

目的:探讨昆明鼠胚胎内细胞团分离方法、原代干细胞克隆分离时机及干细胞传代方法对干细胞建系效率的影响。方法:取昆明鼠3.5d囊胚建胚胎干细胞系,比较全胚培养法与免疫外科法两种内细胞团分离方法对胚胎干细胞建系效率的影响,观察原代克隆的分离时机,机械法传代和酶消化传代对胚胎干细胞建系效率的影响。结果:全胚培养法30个囊胚建系3个,免疫外科法32个囊胚建系4个,两组均可以有效地形成胚胎干细胞系;昆明鼠原代干细胞克隆分离最佳时机是增殖4～6d;5代以前的干细胞以机械传代方法较好,5代后用酶消化法传代效果较好。结论:全胚培养法和免疫外科法均能有效建立昆明鼠胚胎干细胞系,采用机械化与酶消化法相结合传代更适合昆明鼠干细胞建系。     

无动物源性培养系统对人胚胎干细胞生长的支持作用

目的:建立完全非动物源性培养系统,为人胚胎干细胞定向诱导为各系统细胞应用于临床、消除动物源性污染打下基础。方法:分别采用人包皮成纤维细胞、胎儿肌肉细胞及人子宫内膜基质细胞为饲养层细胞,以血清替代品取代动物血清,支持人胚胎干细胞生长,观察其增殖和分化情况。结果:人包皮成纤维细胞、胎儿肌肉细胞均能很好支持人胚胎干细胞生长增殖,并保持90%左右未分化表型:AKP染色强阳性,SSEA-4、TRA-1-81表达强阳性,可见OCT-4 mRNA表达,核型正常。人子宫内膜基质细胞不能支持hESC的生长。结论:完全可以使用非动物源性培养系统支持人胚胎干细胞增殖,从而为胚胎干细胞定向诱导分化应用于临床打下坚实基础     

胚胎干细胞专利相关信息分析

目的对1985年至2004年12月的胚胎干细胞相关专利信息进行详细阅渎和分析,了解国内、外胚胎干细胞相关专利的情况。方法以干细胞及胚胎干细胞为主题词,以德文特(Der- went)数据库为背景,对多个专利数据库进行检索、筛查和分类,建立胚胎干细胞专利数据库。从专利的角度入手,对数据库中的630篇国际及44篇国内胚胎干细胞专利文献进行分类分析。结果胚胎干细胞研究领域的专利申请情况总体呈上升趋势;申请范围主要涉及动物细胞或组织、修饰的细胞、脊椎动物新品种及未分化的人类/动物细胞等方面,国际(13.4%)和国内(20.9%)申请均以涉及动物细胞或组织的占据首位;国内申请中涉及未分化的人/动物细胞的专利较多(19.8%);转基因动物、细胞建系及核移植技术相关的专利申请是胚胎干细胞相关专利中的重要组成部分。结论国内外胚胎干细胞相关信息的分析表明,目前我国在胚胎干细胞研究申请专利方面相对比较宽松,我们应该在涉及胚胎干细胞的分离、建系、在基因工程及细胞组织工程学方面的用途和方法以及胚胎干细胞在药物筛选过程中的用途等方面集中投入力量,争取有新的突破。     

Adaptation of Vero cells to suspension growth for rabies virus production in different serum free media

Vero cells are nowadays widely used in the production of human vaccines. They are considered as one of the most productive and flexible continuous cell lines available for vaccine manufacturing. However, these cells are anchorage dependent, which greatly complicates upstream processing and process scale-up. Moreover, there is a recognized need to reduce the costs of vaccine manufacturing to develop vaccines that are affordable worldwide. The use of cell lines adapted to suspension growth contributes to reach this objective.The current work describes the adaptation of Vero cells to suspension culture in different serum free media according to multiple protocols based on subsequent passages. The best one that relies on cell adaption to IPT-AFM an in-house developed animal component free medium was then chosen for further studies. Besides, as aggregates have been observed, the improvement of IPT-AFM composition and mechanical dissociation were also investigated.In addition to IPT-AFM, three chemically defined media (CD293, Hycell CHO and CD-U5) and two serum free media (293SFMII and SFM4CHO) were tested to set up a serum free culture of the suspension-adapted Vero cells (VeroS) in shake flasks. Cell density levels higher than 2 × 10⁶ cells/mL were obtained in the assessed conditions. The results were comparable to those obtained in spinner culture of adherent Vero cells grown on Cytodex 1 microcarriers.Cell infection with LP-2061 rabies virus strain at an MOI (Multiplicity of Infection) of 0.1 and a cell density of 8 ± 0.5 × 10⁵ cells/mL resulted in a virus titer higher than 10⁷ FFU/mL in all media tested. Nevertheless, the highest titer equal to 5.2 ± 0.5 × 10⁷ FFU/mL, was achieved in IPT-AFM containing a reduced amount of Ca⁺⁺ and Mg⁺⁺. Our results demonstrate the suitability of the obtained VeroS cells to produce rabies virus at a high titer, and pave the way to develop VeroS cells bioreactor process for rabies vaccine production.     

Embryonale Stammzellen der Maus Eigenschaften, Potenzial und Verwendung

During the last few years research on embryonic stem cells has received much public attention due to the fact that these cells are able to differentiate in vitro into many specialized cells and thus may serve as a source for a variety of tissues. The following article focuses on mouse embryonic stem cells (murine ES cells), because research on these cells has given insight into the potential of embryonic stem cells. Murine ES cells are permanent cell lines established from the inner cell mass (ICM) of early embryos (blastocysts). ES cells are undifferentiated pluripotent cells that are able to undergo an unlimited number of cell divisions without loosing the undifferentiated phenotype. The same is true for mouse primordial germ cell lines (murine EG cell lines), that where established from the fetal progenitor cells of primordial germ cells. Mouse embryonic stem cells are used for different purposes. In basic research they are used to study the consequences of mutations within genes that control embryonic development and/or the development of diseases. Because of their ability to differentiate into a variety of specialized cell types, murine ES cells also serve as model systems to establish specific differentiation protocols. In the last few years protocols were established for the in vitro development of undifferentiated embryonic stem cells into differentiated cardiac, skeletal muscle, neural, adipogenic, haematopoietic, endothelial, chondrogenic or vascular smooth muscle cells. Last but not least, studies on mouse ES cells have demonstrated that embryonic cells and their differentiated derivatives can be used to analyse the effects of toxic substances or of pharmaceutical drugs.     

Von der Grundlagenforschung in die Klinik

Translation from the laboratory to the clinic is one of the key problems of stem cell research. One reason for this is that stem cell science is ethically charged and therefore its successful therapeutic application would support its social legitimacy and further funding. We discuss translation both theoretically and with reference to an example, namely efforts regarding the creation of cardiomyocytes from embryonic stem cell lines with the aim to regenerate a patient's myocardium post trauma. Using this case we explain the facts that need to be established scientifically and the subsequent steps that need to be taken in order to develop and implement clinical application. We also discuss aspects of current scientific development related to the moral charge of the research, in particular emerging methods aimed at the derivation of pluripotent cells, such as the hybridization of human DNA and animal egg cells, or the genetic modification of adult somatic cell nuclei in culture to induce pluripotency.     

Development of suspension adapted Vero cell culture process technology for production of viral vaccines

Vero cells are considered as the most widely accepted continuous cell line by the regulatory authorities (such as WHO) for the manufacture of viral vaccines for human use. The growth of Vero cells is anchorage-dependent. Scale-up and manufacturing in adherent cultures are labor intensive and complicated. Adaptation of Vero cells to grow in suspension will simplify subcultivation and process scale-up significantly, and therefore reduce the production cost.Here we report on a successful adaptation of adherent Vero cells to grow in suspension in a serum-free and animal component-free medium (IHM03) developed in-house. The suspension adapted Vero cell cultures in IHM03 grew to similar or better maximum cell density as what was observed for the adherent Vero cells grown in commercial serum-free media and with a cell doubling time of 40–44 h. Much higher cell density (8 × 10⁶ cells/mL) was achieved in a batch culture when three volume of the culture medium was replaced during the batch culture process.Both adherent and suspension Vero cells from various stages were tested for their authenticity using short tandem repeat analysis. Testing result indicates that all Vero cell samples had 100% concordance with the Vero DNA control sample, indicating the suspension cells maintained their genetic stability. Furthermore, suspension Vero cells at a passage number of 163 were assayed for tumorigenicity, and were not found to be tumorigenic.The viral productivity of suspension Vero cells was evaluated by using vesicular stomatitis virus (VSV) as a model. The suspension cell culture showed a better productivity of VSV than the adherent Vero cell culture. In addition, the suspension culture could be infected at higher cell densities, thus improving the volumetric virus productivity. More than one log of increase in the VSV productivity was achieved in a 3L bioreactor perfusion culture infected at a cell density of 6.8 × 10⁶ cells/mL.     

人胚胎干细胞建系研究中的伦理管理

目的：建立国人胚胎干细胞系递交国际干细胞库,并在此基础上建立既符合中国国情又得到国际认可的相关伦理管理体系。方法：在比尔盖茨基金会的资助下,与北京大学生命科学院再生生物学实验室合作,募集胚胎建立人胚胎干细胞系,在此过程中探讨可行的符合国际伦理原则的相关伦理管理机制。结果：成功建立了国人胚胎干细胞系及相关伦理管理体系。结论：进行干细胞研究时应充分重视伦理问题,国际干细胞伦理管理与中国相关伦理原则是可以有机结合的。     

人胚胎干细胞建系研究中的伦理管理

目的：建立国人胚胎干细胞系递交国际干细胞库,并在此基础上建立既符合中国国情又得到国际认可的相关伦理管理体系。方法：在比尔盖茨基金会的资助下,与北京大学生命科学院再生生物学实验室合作,募集胚胎建立人胚胎干细胞系,在此过程中探讨可行的符合国际伦理原则的相关伦理管理机制。结果：成功建立了国人胚胎干细胞系及相关伦理管理体系。结论：进行干细胞研究时应充分重视伦理问题,国际干细胞伦理管理与中国相关伦理原则是可以有机结合的。     

Stem cell research: licit or complicit? Is a medical breakthrough based on embryonic and fetal tissue compatible with Catholic teaching?

In November 1998 biologists announced that they had discovered a way to isolate and preserve human stem cells. Since stem cells are capable of developing into any kind of human tissue or organ, this was a great scientific coup. Researchers envision using the cells to replace damaged organs and to restore tissue destroyed by, for example, Parkinson's disease, diabetes, or even Alzheimer's. But, since stem cells are taken from aborted embryonic and fetal tissue or "leftover" in vitro embryos, their use raises large ethical issues. The National Institutes of Health (NIH) recently decided to fund research employing, not stem cells, but "cell lines" derived from them. The NIH has essentially made an ethical determination, finding sufficient "distance" between cell lines and abortion. Can Catholic universities sponsoring biological research agree with this finding? Probably not. In Catholic teaching, the concept of "complicity" would likely preclude such research. However, Catholic teaching would probably allow research done with stem cells obtained from postpartum placental tissue and from adult bone marrow and tissue. These cells, which lack the pluripotency of embryonic and fetal stem cells, are nevertheless scientifically promising and do not involve the destruction of human life.