淤胆血清“病理微环境”诱导胚胎干细胞向肝细胞分化

目的:探讨淤胆血清"病理微环境"培养体系诱导胚胎干细胞(ESC)向肝细胞分化的可行性。方法:将小鼠ESC细胞系E14在无白血病抑制因子培养基中培养,使其自发分化为拟胚体,加入FGF-4和HGF初步诱导,然后置于5％淤胆鼠血清"病理微环境"筛选培养液中继续培养2周,然后进行细胞形态学观察,白蛋白和CK8/18免疫组化染色,白蛋白与转甲状腺蛋白RT-PCR检测,细胞糖原染色及尿素合成功能分析。结果: 经初步诱导分化的ESC置于5％淤胆血清"病理微环境"筛选培养液中培养,初期细胞生长受抑制,2周后分化为肝细胞样细胞,细胞呈现良好的均质性;免疫组化染色显示白蛋白和CK8/18表达;RT-PCR显示有白蛋白、转甲状腺蛋白等的mRNA转录;细胞有糖原和尿素合成功能。结论:采用含淤胆血清的病理微环境培养体系从经FGF-4和HGF初步诱导的胚胎干细胞中有效筛选出了具有功能的肝细胞,细胞有较好的均质性,为临床肝细胞替代治疗、获取丰富供体细胞来源提供了新思路。     

胚胎干细胞移植对急性损伤肝脏的作用

目的 探索胚胎干细胞移植在急性损伤肝脏中的存活和分化情况.方法 用四氯化碳(CC14)制备小鼠急性肝损伤模型,将BrdU标记的来源于小鼠原始生殖细胞的胚胎干细胞经静脉移植于模型动物体内,分别于移植后2周、4周取出肝脏,用免疫组织化学、免疫荧光双重染色和PAS染色方法检测移植细胞在受体小鼠肝内的分布、存活、白蛋白的表达和糖原代谢.结果 急性损伤小鼠肝脏可见大量肝细胞空泡样变性,有严重出血现象;2周时损伤肝内可见炎性细胞浸润和未吸收的出血区;4周时仍见少量炎性细胞浸润.干细胞移植2周,肝小叶内可见散在分布的BrdU和ALB双阳性着色细胞,PAS染色呈阳性反应;部分小细胞呈BrdU单阳性着色;损伤移植组的肝小叶结构基本恢复.移植4周,损伤肝小叶结构正常,小的BrdU阳性细胞数量增多.结论 原始生殖细胞可以在急性损伤肝脏中存活,并分化为肝细胞和肝小叶内的其他细胞,并明显改善损伤肝的组织结构.     

骨髓间充质干细胞在肝部分切除模型小鼠体内向肝细胞分化

以含20%胎牛血清的DM EM低糖培养基,原代细胞直接贴壁培养,48 h后换液继续培养,分离BALB/C小鼠的骨髓间充质干细胞,该细胞分为CD44 CD29 与CD44-CD29 两群。将第5代骨髓间充质干细胞注入部分肝切除小鼠肝右叶,术后5 d和14 d分别处死动物,测体重、肝重与肝功,制备肝组织芯片,原位杂交和免疫荧光同步检测Y染色体与肝细胞标记(白蛋白或CK 18),并作图像叠加。发现移植组小鼠在移植后5 d与14 d在注射肝叶与非注射肝叶内皆可检出大量同时表达Y染色体与白蛋白及Y染色体与CK 18的细胞。术后14 d,移植组肝重与肝脏器指数高于模型组。表明骨髓间充质干细胞能在有再生需求的小鼠体内向肝细胞分化并参与再生。     

胚胎干细胞C3B鼠视网膜下腔移植分化研究

目的：探讨胚胎干细胞在具有正常视网膜结构的C3B鼠视网膜下腔中的诱导分化情况。 方法:胚胎干细胞传1代后进行拟胚体培养。拟胚体消化成单细胞后联合视黄酸注入C3B鼠视网膜下腔，注射后1周、3周、2月处死小鼠取材进行病理切片、电镜检查和免疫组化检测。 结果:1周时，可见到注射部位视网膜层水肿增厚。3周和2个月时，3只移植眼内出现畸胎瘤，占所有移植眼的25%，其余眼球注射部位仅见瘢痕组织或眼球萎缩。电镜发现增殖的细胞核异型性明显，具肿瘤细胞特征。免疫组化显示：畸胎瘤部分区域MAP-2强阳性反应；可见团状或集落状细胞GFAP强阳性反应；个别细胞Nestin阳性反应。 结论:胚胎干细胞移植入具有正常视网膜结构的C3B鼠视网膜下腔，未能出现ESC向视网膜组织分化或嵌入视网膜组织，相当部分的鼠眼出现了畸胎瘤，其临床安全性和致瘤性是非常值得关注的问题。     

胎儿骨髓源性亚全能干细胞分离培养及诱导肝细胞分化研究

目的研究分离胎儿骨髓源性亚全能干细胞及体内、外向肝细胞分化的潜能。方法利用密度梯度离心结合免疫磁珠方法分离胎儿骨髓源性亚全能干细胞，体外培养鉴定，诱导分化。制备肝功能衰竭重度联合免疫缺陷小鼠（severe combined immunodeficiency，SCID）模型。肝原位输注106左右CD105^＋细胞，对照组分别输注106左右的CD105^-细胞或同等体积的培养液。移植细胞后2d、7d、1个月、3个月时分别取3只鼠的血清及组织标本行肝功能和病理学、免疫组织化学检测。结果免疫磁珠筛选后的免疫细胞化学检测CD105呈弱阳性表达；细胞在对数生长期的倍增时间为30h左右；约传10代后进入衰退期；SCID鼠移植细胞3个月后用鼠抗人白蛋白抗体检测小鼠肝脏中的人白蛋白，可见有点状或小灶状表达。结论来源于胎儿骨髓的亚全能干细胞可以在体外及肝脏微环境下转化为肝细胞样细胞。因此进一步深入研究组织微环境在细胞转化中的机制有十分重要的意义，将为开发诱导胎儿骨髓亚全能干细胞的多向分化潜能提供理论依据。     

精原干细胞移植后的体内迁移、增殖和分化

背景:精原干细胞移植对男性不育的治疗具有潜在的临床应用价值,但移植后干细胞体内迁移、增殖、分化的过程目前尚不完全清楚。目的:观测精原干细胞移植后的体内迁移、增殖和分化过程。方法:以出生后6～10d的雄性C57BL/6小鼠为供体,通过复合酶消化、差速贴壁结合非连续性Percoll密度梯度离心的方法获取精原干细胞;以出生后6周的雄性C57BL/6小鼠为受体,腹腔注射白消安,破坏其内源性生精功能。实验组采用曲细精管微注射法将供体精原干细胞移植入受体睾丸内,对移植后细胞进行PKH26-GL荧光追踪分析,观察其体内迁移过程,以Western Blot和RFQ-PCR法检测睾丸组织α6-Integrin,c-kit,SCF蛋白及mRNA的变化。以未接受化疗和细胞移植的正常同系生小鼠作为阳性对照组,以单侧睾丸曲细精管微注射移植细胞递质作为阴性对照组。结果与结论:PKH26-GL荧光追踪移植细胞,移植后1周部分精原干细胞已向曲细精管基底膜迁移,移植后1个月精原干细胞已从曲细精管管腔迁移至曲细精管基底膜,并分裂增殖,移植后3个月曲细精管管腔内可见大量精子细胞形成。移植后1,2,3个月,各组α6-Integrin,c-kit蛋白表达均呈增加趋势(P0.01),阴性对照组、实验组SCF蛋白表达有增加趋势(P0.05);各组α6-Integrin,c-kit,SCF mRNA的表达均有增加趋势(P0.05)。提示大剂量化疗后,生精上皮内仍存在一定数量的Sertoli细胞,这种精子发生的微环境并未完全破坏,外源性精原干细胞移植后能在受体Sertoli细胞所提供的微环境中增殖和分化。     

胚胎干细胞源性表皮干细胞对小鼠全层皮肤缺损的修复

目的 研究129小鼠胚胎干细胞(ES cell)源性表皮干细胞在同种小鼠全层皮肤缺损的生长和分化,探讨Es细胞源性表皮干细胞对全层皮肤缺损的修复作用.方法 以生物膜为载体,将羊膜诱导后带有核荧光标记的ES细胞源性表皮干细胞直接覆盖小鼠全层皮肤缺损创面.术后1～8周连续取材,HE染色,β1整合素、CK15、CK19、CK10、CEA免疫组织化学和荧光双标显色.结果 术后2周,创面完全长合,较厚的新生皮覆盖创面,基底层细胞增生,形成许多大小不一的细胞柱伸向真皮层,真皮层中可见管腔样结构,免疫荧光双标显示,1～3周新生表皮中可见核标记的细胞呈β1整合素、CK15阳性,真皮层中带有核标记的管状或泡状结构呈β1整合素、CK15阳性;4周后新生表皮开始变薄,基底层细胞呈CK19、CK10阳性,汗腺样结构呈CEA阳性,6～8周新生表皮下可见毛囊样、汗腺样、皮脂腺样等结构.结论 ES细胞源性表皮于细胞植入小鼠全层皮肤缺损创面,可修复缺损的表皮,并在其下真皮层内具有分化为汗腺样、毛囊样和皮脂腺样结构的潜能.     

小鼠骨髓间充质干细胞在体内向肝细胞的转化

为探讨小鼠骨髓间充质干细胞(Bonemarrowmesenchymalstemcells,BMSCs)在体内向肝细胞转化的可能性,将来源于6-8周龄雄性BALB/c小鼠的BMSCs,通过尾静脉注射或经皮肝穿刺直接注入肝脏组织的途径移植入同源正常雌鼠体内。分别于移植术后1、2、4周处死受体雌鼠,取其肝组织,通过荧光原位杂交法(FISH)和免疫组化法同时检测Y染色体的存在和白蛋白的表达,以观察确定所注入的BMSCs在受鼠体内向肝细胞转化的情况。采取经皮直接肝穿刺注射途径移植BMSCs的两个实验组,无论移植细胞是新鲜分离的、还是P3代BMSCs,均可于移植后1周,在受鼠肝脏内检出Y染色体阳性细胞的存在,此类阳性细胞并可同时表达白蛋白。另一方面,经尾静脉注射法进行移植的实验组,于移植后2周,也可在其肝组织内检测到同时表达Y染色体和白蛋白的细胞。本研究证明了骨髓间充质干细胞在体内向肝细胞转化的可能性。     

含淤胆血清的培养体系从大鼠骨髓细胞中筛选与扩增肝干细胞亚群

目的：探讨采用含淤胆血清的培养体系从骨髓细胞中筛选与扩增骨髓源性肝干细胞的可行性。方法：制备含2％、5％、7％和10％淤胆血清的筛选培养液，培养大鼠骨髓细胞，4d时加入肝细胞生长因子促进肝干细胞生长，2周时行免疫组化与RT—PCR检测肝干细胞标志、糖原染色和尿素合成试验分析功能。结果：在2％淤胆血清中，骨髓细胞不能形成克隆，7％与10％的血清则骨髓细胞逐渐凋亡。在5％的淤胆血清时，骨髓源性肝干细胞在此病理筛选培养液中能够生存并选择性生长，而其他类型细胞则脱落凋亡；第2周时，形成肝细胞样集落，细胞表达胚胎时期肝细胞特征性蛋白，具有肝细胞特有糖原和尿素合成功能。结论：含淤胆血清的微环境筛选培养体系能够有效地从骨髓细胞中筛选骨髓源性肝干细胞，为临床肝细胞替代治疗的获取丰富供体细胞来源提供了新的思路。     

干细胞移植用于肝再生治疗的研究

背景：肝脏终末期疾病的常规综合治疗不能达到理想的治疗效果,因此,干细胞移植治疗肝脏疾病成为研究的热点之一,并且已经成为治疗肝脏疾病的新方法。 目的：明确干细胞移植用于肝再生治疗的实验研究和临床应用结果。 方法：分别对不同来源的干细胞如骨髓干细胞、胚胎干细胞、脂肪干细胞以及外周血造血干细胞移植分化治疗肝脏疾病进行体外和体内实验研究分析,并且应用免疫组化染色、病理学以及血清中各项生化指标检测与正常肝脏细胞的生物特性及功能进行比较分析,确定干细胞移植治疗肝脏疾病的效果。 结果与结论：骨髓干细胞、胚胎干细胞、脂肪干细胞以及外周血造血干细胞均可以在特定条件下诱导分化成为肝样细胞,对损伤肝脏不仅有治疗作用而且能够促进肝脏的修复和再生,同时还可以进行干细胞移植转基因治疗。除此之外,干细胞移植可以避免免疫排斥反应的发生,可用于治疗各种类型的肝脏疾病。     

分子影像学方法示踪胚胎干细胞移植治疗急性肝损伤

背景：胚胎干细胞具有多向分化潜能,已被用于急性肝损伤的治疗,但其在体内治疗过程中的增殖迁移情况尚不清楚。 目的：利用分子影像技术监测移植胚胎干细胞在急性肝损伤修复过程中的行为。 方法：利用慢病毒载体,将萤火虫荧光素酶、红色荧光蛋白以及单纯疱疹病毒胸苷激酶三融合基因转入小鼠胚胎干细胞(D3)中,筛选得到稳定整合3个报告基因的D3胚胎干细胞系。将上述胚胎干细胞或分化了6 d的拟胚体细胞通过脾脏注射到急性肝损伤SV129模型小鼠体内,利用生物发光成像技术监测移植的细胞。 结果与结论：RT-PCR结果显示,三融合基因的转入并未影响胚胎干细胞Oct-4和Nanog的表达。利用小动物活体成像系统可以观察到移植细胞从脾脏迁移到肝脏的过程。移植的胚胎干细胞和拟胚体细胞都在肝脏处形成畸胎瘤,由于单纯疱疹病毒胸苷激酶同时也是自杀基因,可以与更昔洛韦作用诱导转基因细胞死亡,通过注射更昔洛韦来抑制畸胎瘤的生长并逐步将其杀死。组织学分析显示,畸胎瘤里包含来自于3个胚层的组织。提示三融合基因的转入并未影响胚胎干细胞的多向分化潜能,且胚胎干细胞用于细胞治疗有潜在的成瘤风险,影响了对肝损伤的修复,治疗策略有待进一步改进,并需要实时监控其在体内的行为。     

Transplantation of bone marrow-derived mesenchymal stem cells into the developing mouse eye

Mesenchymal stem cells (MSCs) have been studied widely for their potential to differentiate into various lineage cells including neural cells in vitro and in vivo. To investigate the influence of the developing host environment on the integration and morphological and molecular differentiation of MSCs, human bone marrow-derived mesenchymal stem cells (BM-MSCs) were transplanted into the developing mouse retina. Enhanced green fluorescent protein (GFP)-expressing BM-MSCs were transplanted by intraocular injections into mice, ranging in ages from 1 day postnatal (PN) to 10 days PN. The survival dates ranged from 7 days post-transplantation (DPT) to 28DPT, at which time an immunohistochemical analysis was performed on the eyes. The transplanted BM-MSCs survived and showed morphological differentiation into neural cells and some processes within the host retina. Some transplanted cells expressed microtubule associated protein 2 (MAP2ab, marker for mature neural cells) or glial fibrillary acid protein (GFAP, marker for glial cells) at 5PN 7DPT. In addition, some transplanted cells integrated into the developing retina. The morphological and molecular differentiation and integration within the 5PN 7DPT eye was greater than those of other-aged host eye. The present findings suggest that the age of the host environment can strongly influence the differentiation and integration of BM-MSCs.     

应用成人骨髓间充质干细胞建立人-猴肝脏嵌合体

背景：建立人骨髓间充质干细胞与猴的嵌合体肝脏对研究干细胞体内增殖与分化具有重要意义。 目的：应用成人骨髓间充质干细胞建立人-猴肝脏嵌合体动物模型。 方法：分离成人骨髓间充质干细胞,纯化并培养至6代,使细胞量大于5×108。转染绿色荧光蛋白基因标记后在B超引导下移植到妊娠10周的胎猴肝脏中,幼猴出生后1个月和3个月,穿刺取肝脏组织活检,切片后荧光显微镜观察带绿色荧光的人源细胞数量及分布,免疫组织化学染色法检测人白蛋白的表达。 结果与结论：荧光显微镜观察发现,幼猴出生后1个月及3个月均发现有人源骨髓间充质干细胞在肝脏内存活,并发生迁移,分布趋向于集中。免疫组织化学检测发现,幼猴出生后1个月及3个月肝脏内有表达人白蛋白的细胞存在,分布与带有绿色荧光的细胞较为一致。提示应用成人骨髓间充质干细胞在猴胚胎早期能够建立人-猴肝脏嵌合体,人源性骨髓间充质干细胞可在猴肝中分化成具有合成白蛋白功能的细胞。     

绿色荧光蛋白转基因小鼠骨髓间充质干细胞干预重症急性胰腺炎大鼠后在多脏器的分布*

背景：利用绿色荧光蛋白转基因小鼠间充质干细胞自身携带荧光性的特点,干预重症急性胰腺炎大鼠后,便于动物体内跟踪观察。 目的：观察绿色荧光蛋白转基因小鼠骨髓间充质干细胞在重症胰腺炎大鼠体内各脏器的分布情况。 方法：直接贴壁法分离培养绿色荧光蛋白转基因小鼠骨髓间充质干细胞,90%融合后消化传代扩增。传至第3代后行CD29+、CD90+、CD34-、CD45-细胞免疫表型鉴定。显微镜下逆行胰胆管注射5%牛黄胆酸钠制造SD大鼠重症急性胰腺炎模型。1 h后,按2×106/只尾静脉注入重症急性胰腺炎SD大鼠体内。分别于6,12,24 h取肝、肾、脑、肺、胰、肠脏器送普通病理检查,观察胰腺病理变化及骨髓间充质干细胞干预重症急性胰腺炎SD大鼠后在各脏器干细胞分布情况及灰度值测定。 结果与结论：胰腺破坏随时间延长而加强,24 h破坏最严重;GFP小鼠CD29阳性细胞91.1%,CD90阳性细胞93.5%,CD34阳性细胞0.82%,CD45阳性细胞2.22%;注射干细胞SD大鼠各脏器均有绿色荧光出现,并随时间增长而增强;在肾脏组织中灰度值最高,脑组织最少。提示骨髓间充质干细胞干预重症急性胰腺炎大鼠后能在各脏器稳定分布。 关键词：重症急性胰腺炎;器官分布;骨髓间充质干细胞;干预;鼠 doi:10.3969/j.issn.1673-8225.2012.10.001     

Enhanced green fluorescent protein is a nearly ideal long-term expression tracer for hematopoietic stem cells, whereas DsRed-express fluorescent protein is not

Validated gene transfer and expression tracers are essential for elucidating functions of mammalian genes. Here, we have determined the suitability and unintended side effects of enhanced green fluorescent protein (EGFP) and DsRed-Express fluorescent protein as expression tracers in long-term hematopoietic stem cells (HSCs). Retrovirally transduced mouse bone marrow cells expressing either EGFP or DsRed-Express in single or mixed dual-color cell populations were clearly discerned by flow cytometry and fluorescence microscopy. The results from in vivo competitive repopulation assays demonstrated that EGFP-expressing HSCs were maintained nearly throughout the lifespan of the transplanted mice and retained long-term multilineage repopulating potential. All mice assessed at 15 months post-transplantation were EGFP positive, and, on average, 24% total peripheral white blood cells expressed EGFP. Most EGFP-expressing recipient mice lived at least 22 months. In contrast, Discosoma sp. red fluorescent protein (DsRed)-expressing donor cells dramatically declined in transplant-recipient mice over time, particularly in the competitive setting, in which mixed EGFP- and DsRed-expressing cells were cotransplanted. Moreover, under in vitro culture condition favoring preservation of HSCs, purified EGFP-expressing cells grew robustly, whereas DsRed-expressing cells did not. Therefore, EGFP has no detectable deteriorative effects on HSCs, and is nearly an ideal long-term expression tracer for hematopoietic cells; however, DsRed-Express fluorescent protein is not suitable for these cells.     

Transplantation of embryonic stem cell-derived endodermal cells into mice with induced lethal liver damage

ESCs are a potential cell source for cell therapy. However, there is no evidence that cell transplantation using ESC-derived hepatocytes is therapeutically effective. The main objective of this study was to assess the therapeutic efficacy of the transplantation of ESC-derived endodermal cells into a liver injury model. The beta-galactosidase-labeled mouse ESCs were differentiated into alpha-fetoprotein (AFP)-producing endodermal cells. AFP-producing cells or ESCs were transplanted into transgenic mice that expressed diphtheria toxin (DT) receptors under the control of an albumin enhancer/promoter. Selective damage was induced in the recipient hepatocytes by the administration of DT. Although the transplanted AFP-producing cells had repopulated only 3.4% of the total liver mass 7 days after cell transplantation, they replaced 32.8% of the liver by day 35. However, these engrafted cells decreased (18.3% at day 40 and 7.9% at day 50) after the cessation of DT administration, and few donor cells were observed by days 60-90. The survival rate of the AFP-producing cell-transplanted group (66.7%) was significantly higher in comparison with that of the sham-operated group (17.6%). No tumors were detected by day 50 in the AFP-producing cell-transplanted group; however, splenic teratomas did form 60 days or more after transplantation. ESC transplantation had no effect on survival rates; furthermore, there was a high frequency of tumors in the ESC-transplanted group 35 days after transplantation. In conclusion, this study demonstrates, for the first time, that ESC-derived endodermal cells improve the survival rates after transplantation into mice with induced hepatocellular injury. Disclosure of potential conflicts of interest is found at the end of this article.     

Osteogenic potential of embryonic stem cells in tooth sockets

Embryonic stem cells (ESCs) are established from blastocysts and give rise to various types of cells and tissues. In the present study, we assessed the osteogenic potential of ESCs using in vitro culture conditions and in vivo differentiation in tooth sockets. An ESC-derived embryoid body (EB) was formed and subsequently induced to an osteogenic lineage. The differentiated EB cells exhibited increased expression of various osteogenic markers as determined by real-time PCR analysis. Likewise, the differentiated EB-derived cells had enhanced alkaline phosphatase activity and calcium accumulation, as determined by cytochemical methods. For in vivo transplantation, mixtures of ESCs and hydroxyapatite/ tricalcium phosphate particles or EBs alone were transplanted into female rat tooth sockets. After 12 weeks, we observed formation of osteogenic structure in the tooth sockets without evidence of teratomas. These data suggest that pluripotent ESCs can serve as an alternative source for the reconstruction of craniofacial structures, as well as for further applications.     

Clonal analysis of human embryonic stem cell differentiation into teratomas

Differentiation of human embryonic stem cells (HESCs) can be studied in vivo through the induction of teratomas in immune-deficient mice. Cells within the teratomas differentiate into all three embryonic germ layers. However, the exact nature of the proliferation and differentiation of HESCs within the teratoma is not fully characterized, and it is not clear whether the differentiation is cell autonomous or affected by neighboring cells. Here, we establish a genetic approach to study the clonality of differentiation in teratomas using a mixture of HESC lines. We first demonstrate, by means of 5-bromo-2'-deoxyuridine incorporation, that cell proliferation occurs throughout the teratoma, and that there are no clusters of undifferentiated-proliferating cells. Using a combination of laser capture microdissection and DNA fingerprinting analysis, we show that different cell lines contribute mutually to the same distinctive tissue structures. Further support for the nonclonal differentiation within the teratoma was achieved by fluorescence in situ hybridization analysis of sex chromosomes. We therefore suggest that in vivo differentiation of HESCs is polyclonal and, thus, may not be cell autonomous, stressing the need for a three-dimensional growth in order to achieve complex differentiation of HESCs. Disclosure of potential conflicts of interest is found at the end of this article.