Clinical isolation and functional characterization of cord blood CD133+ hematopoietic progenitor cells

BACKGROUND: Human cord blood is a relevant source of CD133+ HPCs. Clinical-scale isolation of human umbilical cord blood (UCB) CD133+ HPCs using immunomagnetic microbeads and the CliniMACS clinical cell isolator is reported. CD133+ HPCs isolated after large-scale processing were functionally characterized. STUDY DESIGN AND METHODS: Closed disposable sets were used to process nine different samples of RBC-reduced UCB nucleated cells. In-vitro hematopoietic assays and human xenografts in NOD/SCID mice were performed to assess the functional properties of isolated CD133+ cells. Different mixtures of human cytokines were tested for the ability to expand nascent CD133+ HPCs. Furthermore, freshly isolated CD133+ cells were conditioned in culture medium specifically tested to support in-vitro myogenesis or osteogenesis. RESULTS: Isolation procedures yielded the recovery of an average of 2.53 x 10(6) CD133+ HPCs with a mean recovery of 96 percent (referred to as RBC-reduced samples) and a final sample purity of 82 percent. Purified CD133+ cells had high cloning efficiency, had relevant long-term activity, and were capable of repopulating irradiated NOD/SCID mice. In 10-day stroma-free cultures, a 2-fold and 8.3-fold expansion of colony-forming cells (CFCs) and extended long-term culture-initiating cells, respectively, was obtained. Freshly isolated CD133+ cells differentiated into large nucleated cells expressing either myosin D or osteopontin (as revealed by RT-PCR and immuno-cytochemistry), with a protein/mRNA expression comparable to or even higher than that observed in UCB CD133- nucleated cells in identical culture conditions. CONCLUSION: Collectively, clinical-scale isolation of UCB CD133+ cells provides a relevant amount of primitive HPCs with high hematopoietic activity and in-vitro mesenchymal potential.     

人胎盘组织来源造血干/祖细胞及其特性

背景:近年来的研究表明,除已知的人骨髓、外周血和脐带血中存在造血干/祖细胞外,人胎盘组织中也有造血干/祖细胞存在.目前为止,还缺乏对人胎盘组织造血干/祖细胞的增殖分化特性及人胎盘组织淋巴细胞亚群组成和免疫原性等的深入研究.目的:探究人胎盘组织是否含有比脐带血更丰富的造血干/祖细胞,并对其造血祖细胞系增殖分化能力进行检测,同时对人胎盘组织淋巴细胞亚群组成及表型特征进行分析.设计、时间及地点:开放性实验,于2004-01/2006-12在贵州省细胞工程重点实验室完成.材料:经产妇知情同意,无菌采集遵义医学院附属医院产科健康足月分娩新生儿胎盘和脐带血共12份.淋巴细胞亚群检测试剂盒,CD34绝对计数试剂盒(Becton Dickinson公司):CD34磁珠分选试剂盒,FITC标记的CD38单克隆抗体,抗FITC磁珠和MS/LS免疫磁式细胞分选柱(Miltenyi Biotec).方法:脐带血与RPMI-1640培养基(含体积分数为0.1的胎牛血清)按1:1的比例混合,采用Ficoll-Histopaque分离液离心30min,吸取界面层细胞,PBS洗涤一次,获得脐带血单个核细胞.采用机械法加0.25g/L胶原酶消化制备胎盘组织单个细胞悬液,之后同脐带血单个核细胞分离步骤分离胎盘单个核细胞.流式细胞仪检测胎盘单个核细胞中CD34 CD38-, CD34 CD38 造血干/祖细胞(HSPCs)和淋巴细胞亚群的组成比例.免疫磁珠分选法分选人胎盘CD34 CD38-,CD34 D38 造血干/祖细胞,并分别进行粒细胞-单核细胞集落生成单位、红细胞爆裂型集落生成单位、混合集落生成单位系集落形成培养,以评价其造血祖细胞系增殖分化能力.实验全程用脐带血作平行比较分析.主要观察指标:胎盘和脐带血CD34 造血干/祖细胞组成百分率、祖细胞系集落形成能力、淋巴细胞亚群表型及组成特点.结果:[1]胎盘CD34 造血干/祖细胞百分率是脐带血的8.8倍,差异有显著性意义(P<0.01).[2]胎盘中的淋巴细胞总数、T细胞(CD3 CD2 )、B细胞(CD19 )、Th(CD3 CD4 )细胞及Th/Ts比值均明显低于脐带血,而CD8 CD28-T抑制细胞则明显高于脐带血,差异有显著性意义(P<0.01).[3]胎盘CD34 CD38 造血干/祖细胞亚群培养形成的粒细胞-单核细胞集落生成单位、红细胞爆裂型集落生成单位、混合集落生成单位集落数明显高于CD34 CD38-造血干/祖细胞亚群(P<0.01);胎盘与脐带血造血干/祖细胞中相同表型细胞亚群形成的各系集落数比较,差异无显著性意义(P0.05).结论:人胎盘组织富含CD34 造血干/祖细胞,其CD34 CD38 、CD34 CD38-两个造血干/祖细胞亚群均具有增殖分化为粒细胞-单核细胞集落生成单位、红细胞爆裂型集落生成单位、混合集落生成单位的能力,并且人胎盘组织具有淋巴细胞亚群低比例和抑制性T细胞高比例的特点,使其有望成为造血干/祖细胞移植的新来源.     

脐血造血干/祖细胞免疫表型的流式细胞术双标法分析及其意义

目的比较脐血和骨髓中造血干/祖细胞(HSPC)的免疫表型差异.方法使用流式细胞术(FCM)双标法对38份脐血及10份骨髓HSPC进行免疫表型分析.结果①脐血有核细胞中CD34+细胞所占比例与骨髓中相近,约为0.5%;②脐血CD34+细胞中CD34+CD38-[(17.C4±5.37)%]、CD34+HLA-DR-[(32.65±10.71)%]及CD34+H-CAM+(CD44+)[(77.84±7.69)%]亚群含量均高于骨髓[含量分别为(8.26±3.19)%、(14.05±1.67)%和(70.02±6.40)%],CD34+CD13+、CD34+CD19+亚群比例低于骨髓.结论脐血与骨髓CD34+细胞比例相近,但前者较原始的干细胞含量更高,故脐血是极具潜力的HSPC来源;而脐血CD34+细胞中髓系及淋系祖细胞含量低于骨髓,可能是脐血移植后造血及免疫重建缓慢的原因之一.     

不同时相移植人骨髓间充质干细胞对人脐血CD34^＋细胞植入NOD／SCID小鼠的影响

为了观察不同时相移植人骨髓间充质干细胞（MSC）对脐血（UCB）CD34^＋细胞移植的NOD／SCID小鼠造血重建的影响，明确最佳的移植时机，将体外培养扩增的人骨髓MSC分别于UCBCD34^＋细胞移植同时、移植前48小时及移植后48小时输入经^60Coγ射线照射的NOD／SCID小鼠，观察共移植后42天内小鼠外周血白细胞和血小板变化，并于移植后42天处死小鼠，用FACS检测外周血、骨髓和脾脏人源细胞含量。结果表明：（1）MSC和UCBCD34^＋细胞同时输注可明显降低外周血白细胞和血小板下降幅度，缩短白细胞和血小板恢复时间；二者不同时输注均不降低白细胞和血小板下降幅度，且输注UCBCD34^＋细胞后48小时输注MSC时外周血血小板恢复时间明显晚于同时输注者。（2）与单纯UCBCD34^＋细胞移植相比较，不同时相输注MSC均可促进UCBCD34^＋细胞的植入，三个共输注组间促进骨髓各系造血植入效应无明显差异。结论：人骨髓MSC与UCBCD34^＋细胞共移植时，以同时移植效果最佳，此结果为MSC的临床应用提供了实验依据。     

Mobilization kinetics of CD133+ hematoprogenitor cells for hematopoietic grafting

BACKGROUND: Quantification of CD34+ mononuclear cells is the most important quality control measure for hematopoietic stem cell (HSC) transplantation. A fraction of CD34+ cells also express the CD133 antigen. These cells constitute a group of earlier, less-differentiated HSCs with a potentially higher capacity for engraftment. The correlation between total CD34+ peripheral HSCs and the fraction of these cells that coexpress CD133 was determined before and after automated collection by leukapheresis, as well as the effect of HSC CD133+ dose on hematopoiesis recovery.
STUDY DESIGN AND METHODS: Granulocyte–colony-stimulating factor mobilization of HSCs from the marrow to the peripheral blood (PB) of allogeneic and autologous donors was followed by automated collection through leukapheresis on the fifth day. Quantification of CD34+ and CD133+ cells was performed on PB before collection and in the hematopoietic graft (HG) by flow cytometry.
RESULTS: There was a significant correlation between CD133+ and CD34+ HSCs in the PB before collection and in the final product for grafting (r = 0.62 and 0.64; p < 0.01). CD34+ HSCs per µL in PB and the HG was the only variable that did not correlate (r = 0.18). CD34+/CD133+ correlation increased from 0.33 on PB to 0.94 on the leukapheresis product (p < 0.01). Time to recovery was not related to CD133+ HSCs infused.
CONCLUSION: There was a significant correlation of both number per µL and percentage of CD34+/CD133+ HSCs before and after collection for transplantation; number of CD133+ cells had no apparent clinical impact on time to hematopoiesis regeneration.     

Cesarean section due to fetal distress increases the number of stem cells in umbilical cord blood

BACKGROUND: Umbilical cord blood (UCB) can be used as hematopoietic stem cell source for transplantation. The success of a transplantation is highly correlated with the number of total nucleated cells (TNCs) and CD34+ cells in the UCB. Certain obstetric factors increase the yield of stem cells in the UCB. It is necessary to evaluate optimal conditions in labor to decrease the rate of sample rejection due to low cell count. No data exist regarding the difference between primary and secondary Cesarean sections in terms of efficacy of stem cell harvesting. STUDY DESIGN AND METHODS: Seventy-nine consecutive UCB units from women who had a Cesarean section between 1997 and 2003 were included. The number of TNCs, CD34+ cells, colony-forming units (CFUs), white blood cells (WBCs), nucleated red blood cells (NRBCs), and the total collection volume were compared between cases with primary and secondary Cesarean section. RESULTS: UCB obtained after a Cesarean section due to fetal distress has significantly higher numbers of TNCs, CD34+ cells, NRBCs, and WBCs compared to elective Cesarean section. Of the cases with secondary Cesarean section due to fetal distress, 67 percent resulted in UCB units with sufficient TNC numbers (> or =80 x 10(7) TNCs) compared to 42 percent of the cases with primary Cesarean section. CONCLUSION: Fetal distress increases the number of hematopoietic stem cells mobilized into UCB. Particular effort should be made to collect UCB from newborns who experienced fetal distress.     

Dextran sedimentation in a semi-closed system for the clinical banking of umbilical cord blood

BACKGROUND: The results of current processing procedures for reducing volume and recovering HPCs from umbilical cord blood (UCB) before cryopreservation vary. STUDY DESIGN AND METHODS: Dextran was added to bags containing UCB, followed by sedimentation for 30 minutes. The processed UCB was then frozen. RBCs, nucleated cells, MNCs, CD34+ cells, CFUs and long-term culture-initiating cells (LTC-ICs), viability, and sterility were evaluated. Fractionations in ficoll-hypaque and hydroxyethyl starch (HES) were also run in parallel for comparison. RESULTS: The nucleated cell (NC) recovery and RBC depletion were 86.1 percent and 94.3 percent, respectively (n = 50). Sedimentation with dextran also enabled the recovery of 80.7 percent MNCs and 82.6 percent CD34+ cells (n = 30). Postsedimentation samples displayed no impairment of CFU growth (n = 42, 108.7% CFU-C, 104.6% CFU-GEMM, 107% CFU-GM, and 95.7% BFU-E). Long-term cultures on five paired samples before and after sedimentation generated similar numbers of CFU-C each week (p = 0.88). Limiting dilution analysis of 12 paired pre/postsedimentation samples showed comparable median proportions of LTC-ICs (1/6494 vs. 1/5236; p = 0.18). The cell viability of 24 samples of thawed UCB after sedimentation was 90.3 percent (77.5-96%) and the recovery of CFU-C, CFU-GEMM, CFU-GM, and BFU-E of 11 postsedimentation samples was 93.4 percent, 84.9 percent, 92.3 percent, and 83.4 percent, respectively. NC recovery was significantly higher after treatment with dextran than with ficoll-hypaque (n = 30; 88.5% vs. 29.1%; p<0.005) and HES treatment (n = 21; 88.5% vs. 76.4%; p = 0.004). However, MNCs, CD34+ cells, CFUs, LTC-ICs, and RBCs were comparable. Two cycles of dextran sedimentation recovered 93.9 percent of NCs with cell viability of 98.6 percent (96.5-100%), whereas 11.7 percent of RBCs were retained (n = 20). The final yield volume was 33.5 (28-41) mL. CONCLUSION: In a semi-closed system, dextran sedimentation enabled volume reduction of UCB without significant quantitative and qualitative losses of HPCs.     

Human cord blood applications in cell therapy: looking back and look ahead

INTRODUCTION: Human umbilical cord blood (UCB) has been used as a reliable source of stem cells for blood-borne diseases and disorders. Recent advances in cell reprogramming technology to produce induced pluripotent stem (iPS) cells, which can be differentiated to multiple adult cell types, has further expanded the potential of cord blood cell therapy for treatment of non-blood-borne diseases. However, in order to harness this breakthrough technology and to provide clinical-grade cells for the patient, standardization of iPS production and differentiation, and good manufacturing practice (GMP) need to be employed. AREAS COVERED: UCB is an ethical source of stem cells and has been used to treat diseases including leukemia, cancer and blood disorders. The development of iPS cell technology could potentially greatly increase the application of cord blood cells as a treatment for a broader range of diseases, UCB-iPS banks could, therefore, be a valuable complementary source of clinical-grade cells for cell therapy. The current applicability of GMP to UCB and UCB-iPS cell-based cell therapy will be discussed. EXPERT OPINION: Although cord blood stem cell therapies have been practiced for decades, UCB-iPS cell therapies are a new innovation currently in development. Successful clinical applications of such novel cell therapies will depend on the production of GMP-compliant cells and the establishment of cell banks.     

CD133+CD34+ and CD133+CD38+ blood progenitor cells as predictors of platelet engraftment in patients undergoing autologous peripheral blood stem cell transplantation

BackgroundHematopoietic stem cells (HSC) have been characterized by CD34+ expression and an adequate dose of CD34+ cells is associated with a complete engraftment. CD133 is a more specific marker of HSC.Materials and methodsWe studied the relationship between graft content of CD34+, CD133+, and CD38+ cells and trilineage engraftment after autologous stem cell transplantation in patients with different hematological disorders. Blood samples were obtained before and after mobilization with recombinant granulocyte-colony stimulating factor (G-CSF, 16 μg/kg), from apheresis collections, and after transplantation.ResultsCell subsets were quantified by flow cytometry, and the dose of each population infused was correlated with success of engraftment. G-CSF induced mobilization of CD133+CD38+ cells (12.6-fold) and CD133+CD34+ cells (14.7-fold). A correlation was observed between the infused dose of CD133+CD34+ and CD133+CD38+ cells and platelet engraftment.ConclusionCD133+CD34+ and CD133+CD38+ cells were mobilized with G-CSF and these cell subsets were correlated with platelet engraftment.     

Developmental variation in stem-cell markers from human fetal liver and umbilical cord blood leukocytes

Fetal tissues containing haematopoietic stem cells (HSC) are of potential value for allogeneic transplantation and gene therapy. Flow cytometry was used to investigate CD34+ cells from human fetal livers and umbilical cord (placental) blood (UCB). CD34+ cells, expressed as a proportion of CD45-positive leukocytes, were much more abundant in fetal livers (mean 38%) than in UCB (mean 0.3%), but fetal liver cells had lower proportions of CD34+HLA-DR+ and CD34+ CD38+ subsets. In fetal liver, there was a strong and highly significant inverse correlation between CD34+ cells (as a proportion of total leukocytes) and gestational age; no such relationship was found for subsets of CD34+ cells coexpressing CD38 or CDw90 (Thy-1), but CD34+HLA-DR+ cells were less abundant in first- compared to second-trimester livers. In UCB, a trend towards decreasing CD34+ cells (as a proportion of total leukocytes) with increasing gestational age in late pregnancy was also observed. The composition of fetal leukocytes changes during development, and therefore the timing of fetal HSC harvesting could be of relevance to transplantation outcome.     

干细胞因子对内皮细胞增殖、迁移、管状形成能力的影响及对CD133+细胞的趋化效应

目的 探讨干细胞因子(SCF)对脐静脉内皮细胞(HUVEC)增殖、迁移、管状形成能力的影响,以及对CD133+细胞的趋化效应.方法 应用MTT及CCK-8增殖分析法检测HUVEC在不同细胞因子[空白试剂、SCF、血管内皮生长因子(VEGF)、抗人SCF、人IgG]条件下增殖能力的差异性;采用细胞划痕法与Matrigel体外三维成型法分别检测内皮细胞的增殖、迁移和管状形成能力;并应用Transwell技术检测不同细胞因子诱导的CD133+细胞体外趋化效应.结果 MTT及CCK-8增殖分析结果显示SCF无HUVEC增殖刺激活性;SCF可显著提升HUVEC迁移能力;SCF呈剂量依赖性增强HUVEC 管状形成能力,在适宜浓度SCF(100 ng/ml)作用下,HUVEC完整小管形成数量[(30.0 ±3.4)/105HUVEC]显著高于空白试剂组[(5.0±2.6)/105HUVEC,P<0.01];SCF可高效诱导CDl33+细胞体外趋化,SCF组[(118.0±6.5)/104CD133+细胞]Transwell小室跨膜迁移细胞数显著高于空白试剂组[(47.0±4.7)/104CDl33+细胞,P<0.01].结论 SCF可显著增强HUVEC的迁移及管状形成能力,并有效诱导CD133+细胞体外趋化,提示SCF/c-kit信号转导在内皮细胞及其祖细胞的血管新生与血管发生过程中可能发挥重要作用.

Abstract：

Objective To explore the effects of stem cell factor (SCF) on proliferation, transmigration, capillary tube formation of human umbilical vein endothelial cells (HUVEC) and on the chemotaxis of CD133+ cells. Methods In the presence of blank control, SCF, vascular endothelial growth factor ( VEGF) , anti-human SCF (anti-SCF) or human IgG, the difference in proliferation capacity of HUVEC was analyzed by MTT and CCK-8 methods, and wound scratch assay and three-diamensional in vitro Matrigel assay were used for transmigration and capillary tube formation of HUVEC, respectively. In addition, the chemotaxis of CD133 + cells sorted from human umbilical cord blood by flow cytometry was investigated by Transwell migration assay. Results SCF didn't improve the proliferative capacity of HUVEC, but significantly enhanced the transmigration capacity, and increased capillary tube formation in a dose-dependent manner.The number of intact tubules [(30.0 ±3.4)/105 HUVEC] formed by HUVECs in the presence of the optimal concentration of SCF (100 ng/ml) was remarkably higher than that in blank control group [(5.0 ±2.6)/105HUVEC,P <0.01]. SCF also significantly induced a chemotactic response of CD 133+ cells, the transmembrane migration cell number into Transwell lower chamber was significantly higher in SCF group [(118.0 ±6.5)/104 CD133+ cells] than in blank control group [(47. 0 ±4. 7)/104 CD133 + cells,P <0.01]. Conclusions SCF significantly promotes the transmigration and capillary tube formation of HUVEC, and induces a chemotactic response of CD133 + cells. SCF/c-kit signaling possibly plays a critical role in regulating angiogenesis of vascular endothelial cells and vasculogenesis of endothelial progenitor cells.     

脐带结缔组织多潜能干细胞向内皮及心肌方向的分化

背景:脐带结缔组织富含多潜能干细胞,其免疫原性弱、增殖力强。目的:验证体外培养人类脐带结缔组织(wharton’s jelly)中多潜能干细胞向内皮细胞及心肌细胞方向的诱导分化。方法:贴块法培养人类脐带结缔组织多潜能干细胞。结果与结论:①流式细胞仪进行表型鉴定,多潜能干细胞CD105、CD73、CD90、CD44、CD54阳性,而CD45、CD34、CD106和CD133阴性。②加入血管内皮生长因子及碱性成纤维细胞诱导后,细胞表现内皮细胞形态,可以吞噬ac-LDL并结合UEA-1。③以5-氮杂胞甘诱导后经免疫组织化学染色显示,心肌细胞标记物肌钙蛋白Ⅰ和β肌球蛋白重链表达阳性。提示在体外培养的条件下,可以从脐带结缔组织中得到大量干细胞,该细胞可以向心肌及内皮方向分化。     

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.     

犬外周血淋巴管内皮祖细胞的分选及其向内皮细胞的诱导分化研究

目的研究犬外周血中CD34^＋／CD133^＋／VEGFR-3^＋淋巴管内皮祖细胞的生物学特征，探讨血管内皮生长因子-C（VEGF-C）／血管内皮生长因子受体3（VEGFR-3）信号途径在淋巴管内皮祖细胞向淋巴管内皮细胞分化中的作用。方法用密度梯度离心法从犬外周血分离单个核细胞，再用流式细胞仪从单个核细胞分选VEGFR-3^＋细胞。通过VEGF-C诱导使VEGFR-3^＋细胞向内皮细胞分化。在扫描电镜和透射电镜下观察细胞表面形态和超微结构，并在共聚焦激光扫描显微镜下观察特征性标志物的表达。结果VEGFR-3^＋细胞同时表达CD34和CD133。经流式细胞仪分析，外周血单个核细胞中CD34^＋／VEGFR-3^＋细胞的含量约为0.13％，VEGFR-3^＋／CD133^＋细胞的含量约为0.08％。CD34^＋／CD^33^＋／VEGFR-3^＋细胞的体积较大，直径约为15μm。经VEGF-C诱导后，细胞数目增多。细胞变为梭形，伸出板状伪足和许多丝状伪足。诱导后1周，细胞表达血管性血友病因子。诱导后2周，细胞表面出现小凹，细胞内可见Weibel-Palade小体。细胞表达淋巴管内皮细胞特异性标志物LYVE-1，CD133标志消失。结论在VEGF-C诱导作用下，外周血中的CD34^＋／CD133^＋／VEGFR-3^＋淋巴管内皮祖细胞能向淋巴管内皮细胞分化。VEGF-C／VEGFR-3信号途径在淋巴管内皮祖细胞的分化过程中起着重要作用。     

CD133 expression is not restricted to stem cells, and both CD133+ and CD133- metastatic colon cancer cells initiate tumors

Colon cancer stem cells are believed to originate from a rare population of putative CD133+ intestinal stem cells. Recent publications suggest that a small subset of colon cancer cells expresses CD133, and that only these CD133+ cancer cells are capable of tumor initiation. However, the precise contribution of CD133+ tumor-initiating cells in mediating colon cancer metastasis remains unknown. Therefore, to temporally and spatially track the expression of CD133 in adult mice and during tumorigenesis, we generated a knockin lacZ reporter mouse (CD133lacZ/+), in which the expression of lacZ is driven by the endogenous CD133 promoters. Using this model and immunostaining, we discovered that CD133 expression in colon is not restricted to stem cells; on the contrary, CD133 is ubiquitously expressed on differentiated colonic epithelium in both adult mice and humans. Using Il10-/-CD133lacZ mice, in which chronic inflammation in colon leads to adenocarcinomas, we demonstrated that CD133 is expressed on a full gamut of colonic tumor cells, which express epithelial cell adhesion molecule (EpCAM). Similarly, CD133 is widely expressed by human primary colon cancer epithelial cells, whereas the CD133- population is composed mostly of stromal and inflammatory cells. Conversely, CD133 expression does not identify the entire population of epithelial and tumor-initiating cells in human metastatic colon cancer. Indeed, both CD133+ and CD133- metastatic tumor subpopulations formed colonospheres in in vitro cultures and were capable of long-term tumorigenesis in a NOD/SCID serial xenotransplantation model. Moreover, metastatic CD133- cells form more aggressive tumors and express typical phenotypic markers of cancer-initiating cells, including CD44 (CD44+CD24-), whereas the CD133+ fraction is composed of CD44lowCD24+ cells. Collectively, our data suggest that CD133 expression is not restricted to intestinal stem or cancer-initiating cells, and during the metastatic transition, CD133+ tumor cells might give rise to the more aggressive CD133(- )subset, which is also capable of tumor initiation in NOD/SCID mice.     

Differential responses of human neural and hematopoietic stem cells to ethanol exposure

The mechanisms underlying fetal developmental defects caused by maternal ethanol (EtOH) consumption remain unclear. The symptoms of fetal alcohol syndrome (FAS) include neurological and immunological dysfunctions that are linked to cell reduction in these systems. Neural (NSC) and hematopoietic stem cells (HSC) may be targets for the cytotoxic effects of EtOH. Furthermore, protein kinase C (PKC) signal transduction systems of these stem cells may be involved in EtOH-induced cell death. Purified CD34+ human fetal liver hematopoietic stem cells (HSC) and CD133+/nestin+ human neural stem cells (NSC) were exposed to 0.1-10 mM EtOH. A range of indices of cell damage indicated that these doses of EtOH were deleterious to NSC, but had no observable effects on HSC. Furthermore, the colony-forming ability of NSC was completely inhibited by 5 mM EtOH treatment, whereas HSC were unaffected by even 20 mM EtOH. These results suggest that NSC are much more sensitive to EtOH than HSC. Classic and novel PKC isozyme protein expressions in the membrane fraction of cells were differentially affected by EtOH exposure across the two stem cell types. Concentrations of EtOH capable of inducing NSC, but not HSC, death also changed apoptosis-associated PKC isozyme expression in the membrane of NSC, but not HSC. Therefore, PKC expression may mediate the susceptibility of NSC to EtOH-induced cytotoxicity via cell signal transduction pathways. The toxic effect of EtOH on NSC may lead to the decreased neural cell number observed in FAS patients. The comparable immunity of HSC to the deleterious effects of EtOH exposure indicates that the susceptibility of NSC is not simply due to their being stem cells and also may explain the relative lack of hematopoietic problems associated with FAS.     

Levels of circulating endothelial progenitor cells are related to uremic toxins and vascular injury in hemodialysis patients

Summary.  Background : Patients suffering from chronic kidney diseases (CKD) exhibit cardiovascular diseases and profound endothelial dysfunction. CKD patients have reduced numbers of endothelial progenitor cells, but little is known about the factors influencing these numbers. Objectives : Among these factors, we hypothesized that uremic toxins and vascular injury affect endothelial progenitor cells. Patients/methods : Thirty-eight hemodialysis patients were investigated and compared with 21 healthy controls. CD34+CD133+ immature progenitors, CD34+KDR+ endothelial progenitors cells (EPC) and myeloid EPC (mEPC) were counted in peripheral blood. Levels of uremic toxins β₂-microglobulin, indole-3 acetic acid, indoxylsulfate, p-cresylsulfate and homocysteine were measured. Vascular injury was assessed in hemodialysis (HD) patients by measuring aortic pulse wave velocity and plasma levels of endothelial microparticles. In vitro experiments were performed to study the effect of uremic toxins on apoptosis of progenitor cells. Results and conclusions : CD34+CD133+ immature progenitor cell number was negatively correlated with the levels of uremic toxins β₂-microglobulin and indole-3 acetic acid. In vitro , indole-3 acetic acid induced apoptosis of CD133+ cells. These data indicate uremic toxins have a deleterious role on progenitor cells, early in the differentiation process. Moreover, mEPC number was positively correlated with markers of vascular injury–pulse wave velocity and endothelial microparticle levels. This suggests that vascular lesions could stimulate progenitor cell mobilization, even in a context of reduced EPC induced by CKD. In conclusion, uremic toxins and vascular injury appear to affect endothelial progenitor cell biology in CKD.     

不同来源人造血干/祖细胞在NOD/SCID小鼠体内归巢能力的差异

目的 比较不同来源的人造血干／祖细胞在NOD／SCID小鼠体内归巢能力的差异性，并探讨其体内归巢能力与膜表面归巢相关分子CXCR4表达水平的相关性。方法 采用流式细胞术（FACS）检测新鲜脐血、冻存脐血、动员后外周血（mPB）及骨髓来源的CD34^＋细胞表面CXCR4表达水平；将荧光染料CFSE标记的人CD34^＋细胞移植人接受照射的NOD／SCID小鼠，移植后20小时检测已归巢于NOD／SCID小鼠骨髓及脾脏中不同来源的人CD34^＋细胞，计算其相应的骨髓及脾脏归巢效率；并将小鼠股骨制成组织切片，荧光显微镜下观察人CD34^＋细胞在小鼠骨髓腔内的分布。结果 新鲜脐血、冻存脐血、mPB和骨髓CD34^＋细胞膜表面CXCR4表达阳性率分别为（49.52±1．12）％。（46．12±2．29）％，（48．50±2．48）％和（65．39±1．27）％，CD34^＋细胞在NOD／SCID小鼠骨髓的归巢效率分别为（3．00±0．44）％，（2．84±0．46）％，（4．06±0．70）％及（5．76±0．52）％；在脾脏的归巢率分别为（1．88±0．12）％，（1．80±0．15）％，（1．90±0．22）％，（2．16±0．34）％。归巢的CD34^＋细胞主要分布于小鼠股骨的骨内膜区域。结论 脐血CD34^＋细胞膜表面CXCR4水平低于mPB和骨髓。经冻存复苏后脐血CD34^＋细胞膜表面CXCR4水平略有下调。脐血CD34^＋细胞在照射NOD／SCID小鼠的骨髓归巢效率低于mPB和骨髓。     

人脐血源性间充质干细胞向心肌细胞的诱导分化(英文)

背景：与骨髓间充质干细胞相比，脐带血巾的细胞被视为“非常年轻”的细胞，其增殖和分化能力不会随着捐助者的年龄增加而减低，可能是一个极好的骨髓间充质干细胞的替代来源。目的：观察体外诱导脐血间充质干细胞分化成心肌细胞的特点。设计、时间及地点：观察性实验，于2005—03／2007—02在北京世纪坛医院完成。材料：收集获知情同意健康产妇脐血细胞。方法：分离单个核细胞，从中进一步分离间充质干细胞，传代培养至第3代，应用免疫荧光流式细胞仪标记间充质干细胞特异性抗原CD34，CD44和CD90。5-氮胞苷诱导分化4周后，免疫组织化学染色和反转录-聚合酶链反应分别检测心肌细胞标志物肌钙蛋白Ⅰ，GATA4和β-肌球蛋白重链的表达。主要观察指标：心肌细胞标志物肌钙蛋白Ⅰ，GATA4和β肌球蛋白重链的表达。结果：脐血源性间充质干细胞经5-氮胞苷诱导分化后，呈现成纤维细胞样形态和克降增殖特点。免疫分型与骨髓来源间质干细胞一致，且免疫组织化学染色和反转录-聚合酶链反可检测到肌钙蛋白Ⅰ，GATA4和β-肌球蛋白重链的表达。结论：脐血源性间充质干细胞能够被诱导分化成心肌样细胞，并显示为心肌细胞的表观特征。