P-Selectin coated microtube for enrichment of CD34+ hematopoietic stem and progenitor cells from human bone marrow

BACKGROUND: Enrichment and purification of hematopoietic stem and progenitor cells (HSPCs) is important in transplantation therapies for hematologic disorders and in basic stem cell research. Primitive CD34+ HSPCs have demonstrated stronger rolling adhesion on selectins than mature CD34- mononuclear cells (MNCs). We have exploited this differential rolling behavior to capture and purify HSPCs from bone marrow by perfusing MNCs through selectin-coated microtubes. METHODS: Bone marrow MNCs were perfused through the cell-capture microtubes coated with adhesion molecules. We washed the device lumen and visualized and estimated captured cells by video microscopy. Adherent cells were eluted by high shear, calcium-free buffer, and air embolism. We used immunofluorescence staining followed by flow cytometry to analyze CD34+ HSPCs. RESULTS: CD34+ HSPC purity of cells captured in adhesion molecule-coated devices was significantly higher than the fraction of CD34+ cells found in bone marrow MNCs [mean (SE) 2.5% (0.8%)]. P-selectin-coated surfaces yielded 16% to 20% CD34+ cell purity, whereas antibody-coated surfaces yielded 12% to 18%. Although CD34+ cell purity was comparable between selectin and antibody surfaces, the total number of CD34+ HSPCs captured was significantly higher in P-selectin devices (approximately 5.7 x 10(4) to 7.1 x 10(4)) than antibody devices (approximately 1.74 x 10(4) to 2.61 x 10(4)). CONCLUSIONS: P-selectin can be used in a compact flow device to capture HSPCs. Selectin-mediated capture of CD34+ HSPCs resulted in enrichment approximately 8-fold higher than the CD34+ cell population from bone marrow MNCs. This study supports the hypothesis that flow-based, adhesion molecule-mediated capture may be a viable alternative approach to the capture and purification of HSPCs.     

Adhesion of CD34+ marrow precursors to human stroma is related to alphaSM actin expression by human marrow myofibroblasts

We have studied the adhesion of human marrow CD34(+) precursors to stromal layer of nontransformed human marrow myofibroblasts (normal stroma) and to different stromal cell lines immortalized by T (PU-34) or t and T (L88/5, L87/4, L2Ori-, KM-102) oncogenes from simian virus 40 and E6, E7 oncogenes from human papilloma virus 16 (HS-27A, HS-23). Flow cytometry and Western blotting studies showed that cells from all lines were stromal myofibroblasts similar to normal stroma. Using an original method of adhesion measurement, we found that adhesion of CD34(+) cells was significantly increased on PU-34 cell layer as compared to normal stroma (43% vs. 27%) whereas adhesion on HS-27A and HS-23 was significantly decreased (11% and 8.5%, respectively), and adhesion on L88/5, L87/4, KM-102 and L2Ori- was negligible to nil (<6%). Adhesion of CD34(+) cells to stromal layers paralleled the expression of alpha smooth muscle (alphaSM) actin within the microfilaments of the cells from the different lines and was inversely correlated to their anchorage-independent growth in semisolid agar. These data show that adhesion to the stromal layer of CD34(+) cells is related to the alphaSM actin microfilamentous network in marrow myofibroblasts and that transformation can negatively affect this microfilamentous network and therefore adhesion of hematopoietic precursors.     

人骨髓CD34＋干细胞分离培养及血管内皮生长因子165诱导分化的作用

背景:有研究证实,骨髓中CD34+干细胞在一定条件下具有向内皮细胞分化的潜能.目的:体外分离、纯化、培养和扩增人CD34+造血干细胞,并检测其免疫学表型,观察血管内皮生长因子对其体外诱导分化后细胞免疫表型的变化.设计、时间及地点:细胞学观察实验,于2005-10/2007-10在南方医科大学神经生物学教研室完成.材料:骨髓来源于健康供者.方法:利用Percoll梯度分离、贴壁筛选法及单克隆培养法分离培养、扩增人骨髓CD34+干细胞.采用脂质体介导转染法,选生长良好的传代细胞,以血管内皮生长因子165基因转染人骨髓CD34+干细胞.主要观察指标:采用免疫荧光和流式细胞术检测人骨髓CD34+干细胞免疫学表型.经血管内皮生长因子165基因转染后,人骨髓CD34+干细胞的表型变化以及血管内皮生长因子的分泌情况.结果:体外分离培养出高度同源性的人骨髓CD34+干细胞,细胞形态呈成纤维细胞样.CD44、CD29和c-kit阳性,CD31和CD54阴性;经血管内皮生长因子165诱导后,人骨髓CD34+干细胞表面标志CD44表达降低,CD31升高,呈现典型的内皮细胞表型,并且获得大量分泌血管内皮生长因子的能力.结论:采用Percoll分离液梯度离心继以贴壁筛选法及单克隆培养法联合筛选分离,可培养扩增}H高度同源的CD34+干细胞,经血管内皮生长因子基因转染后,CD34+干细胞呈典型的内皮细胞表型,验证了其具有向内皮细胞分化的潜能.     

胎儿骨髓间质干细胞与细胞因子对脐血CD34+细胞扩增作用

目的　探讨胎儿骨髓间质干细胞对CD34 细胞体外扩增的造血支持作用。方法　体外分离、纯化胎儿骨髓间质干细胞 ;Mini MACS免疫磁珠分选 3份脐血CD34 细胞 ;建立胎儿骨髓间质干细胞与CD34 细胞共培养体系 :第 1组为单独CD34 细胞培养 ,第 2组为胎儿骨髓间质干细胞 CD34 细胞共培养 ,第 3组为细胞因子 (干细胞因子 ,白细胞介素 3,Flt3配体 ,血小板生成素 ) CD34 细胞共培养 ,第 4组为胎儿骨髓间质干细胞 细胞因子 CD34 细胞共培养。用流式细胞仪检测不同培养时间的CD34 细胞。结果　胎儿骨髓间质干细胞表达CD2 9,CD4 4 ;免疫磁珠分选CD34 细胞的平均纯度为 97.4 % ;胎儿骨髓间质干细胞 CD34 细胞共培养 2 8d ,有核CD34 细胞仍占有核细胞的 6 .4 3% ;CD34 细胞在胎儿骨髓间质干细胞、细胞因子作用下培养 2 8d ,有核细胞总数、CD34 细胞数分别被扩增 1.6 5× 10 5倍、788倍。结论　胎儿骨髓间质干细胞可有效扩增脐血造血干 /祖细胞。     

人正常骨髓 CD_(34)~ 造血细胞的形态学与细胞化学特征

目的：探讨ＣＤ３４＋造血细胞的形态学特征。方法：采用免疫磁珠－流式细胞仪分选二步法获取高纯度的人正常骨髓ＣＤ３４＋造血细胞。结果和结论：ＣＤ３４＋造血细胞从形态上可分为３型，Ⅰ型胞体略大于淋巴细胞，各种细胞化学染色阴性，最原始，拟定候选干细胞群；Ⅱ型为典型的小淋巴细胞状，细胞化学亦为阴性，拟定多向祖细胞阶段；Ⅲ型胞体极不均一，依分化方向不同其细胞化学表现为±～＋＋，拟定定向祖细胞阶段。     

珍珠层人工骨与人骨髓基质细胞的生物相容性

目的:探讨人骨髓基质细胞与珍珠层人工骨的生物相容性,为选择更好的骨组织工程材料提供实验依据。方法:实验于2005-05/10在南方医科大学南方医院脊柱骨科实验室完成。采用模压成型专利技术,将珍珠层粉与消旋聚乳酸制成三维多孔材料,孔径200～500nm。将制作好的材料切制成8mm×8mm×2mm大小的块状,乙醇及去离子水湿化,自然干燥,高温湿热灭菌后备用。骨髓基质细胞取自健康成年男性(自愿捐献)。体外培养人骨髓基质细胞,与珍珠层-聚乳酸复合人工骨共同培养。实验分两组:珍珠层人工骨组加入块状的珍珠层人工骨,对照组不加处理因素。采用倒置相差显微镜、扫描电镜进行形态学观察,噻唑蓝法进行细胞增殖等指标测定,考马斯亮蓝法微量测定细胞蛋白含量。结果:①随着培养时间的延长,各组细胞数量逐渐增加,各时间点珍珠层人工骨组与对照组相比,差异无显著性意义(P>0.05)。②培养3d,珍珠层人工骨组和对照组蛋白含量相比较差异无显著性意义(分别为0.39±0.02,0.37±0.03,P>0.05);培养7d后,珍珠层人工骨组蛋白含量高于对照组,差异有显著性意义(分别为0.97±0.05,0.83±0.03,P<0.05)。③倒置相差显微镜观察,7d时可见细胞在珍珠层人工骨周围密集生长。珍珠层人工骨组细胞生长状态与对照组相比差异不明显,未见到细胞大量凋亡、衰老及异常分裂现象。④扫描电镜观察,共同培养第7天,可见梭形骨髓基质细胞大量紧密生长在珍珠层人工骨表面,呈集束状排列,边缘部分细胞可见到伪足。结论:珍珠层人工骨具有良好的生物相容性,可作为骨髓基质细胞的载体而应用于骨组织工程的研究。     

Multipotency of Flk1CD34 progenitors derived from human fetal bone marrow

We report that a cell population derived from human fetal bone marrow, termed Flk1+CD34- multipotent stem cells, can differentiate not only into osteogenic, adipogenic, and endothelial lineages but also into hepatocyte-like cells and neural and erythroid cells at the single-cell level. We depleted mononuclear cells from fetal bone marrow of CD45+, GlyA+, and CD34+ cells with the use of micromagnetic beads, then cultured them by limiting dilution. Three single colonies were harvested, expanded, and characterized. The clones have been expanded for more than 50 cell doublings, and cell-doubling time was about 30 hours. About 90% cells were in the G(0)/G(1) phase of the cell cycle, and the cells from the single colony maintained Flk1+ and CD34-. Because fetal bone marrow-derived Flk1+CD34-multipotent stem cells have the capacity for self-renewal and multilineage differentiation even after being expanded for more than 50 cell doublings, they may be an ideal source of stem cells for the treatment of inherited or degenerative diseases.     

Use of lectins for characterization and purification of human bone marrow cells that express CD34.

The binding of lectins to nucleated cells from human bone marrow was studied in a search for markers that can be used to subdivide further immature hemopoietic cells that are characterized by their expression of CD34. Low-density bone marrow cells were indirectly labeled with biotinylated lectins and streptavidin-R-phycoerythrin (SA-RPE) together with FITC-labeled monoclonal anti-CD34. Four-parameter flow cytometric analysis was then performed and list mode data analyzed. Of the 21 lectins tested, only a few showed differential staining of CD34+ versus CD34- cells. These include soybean agglutinin (SBA) and Ulex europaeus agglutinin I (UE). Lycopersicon esculentum (LE) and Erythrina cristigalli (EC) reacted preferentially with, respectively, CD34+ and CD34- cells, suggesting their usefulness in some method to enrich for CD34+ cells. This possibility was tested by passing cells labeled with biotinylated lectins over a column containing streptavidin-coated beads. CD34+ cells could be enriched > 10-fold by competitive (sugar) elution of LE-labeled cells from the column. Similarly, depletion of biotinylated EC-labeled cells by passage through the streptavidin column enriched CD34+ cells several fold. The results of these studies document the reactivity of a large panel of lectins with subpopulations of nucleated bone marrow cells and indicate that certain lectins could possibly be used for development of cell separation procedures aimed at the selective enrichment of cells that express CD34.     

Decreased stroma adhesion capacity of CD34+ progenitor cells from mobilized peripheral blood is not lineage- or stage-specific and is associated with low beta 1 and beta 2 integrin expression

Molecular mechanisms leading to mobilization of hematopoietic cells from bone marrow (BM) to peripheral blood (PB) involve modulation of adhesion molecule expression on these cells that probably result in changes in adhesion capacity to the microenvironment. However, it is not clear whether these changes involve different stages or lineages of progenitor cells. In this study, we compared the capacity of mature and immature clonogenic progenitor cells from granulocyte colony-stimulating factor (G-CSF)-mobilized PB and normal BM CD34+ cells to adhere to complete marrow stroma. This functional capacity was assessed concurrently with molecular expression on CD34+ cells of integrins VLA-4 (alpha 4/beta 1), VLA-5 (alpha 5/beta 1), and LFA-1 (alpha L/beta 2) by interindividual (between mobilized PB and normal BM) and intraindividual (between mobilized PB and steady-state BM and PB in the same patient) analysis. The proportion of adherent clonogenic progenitor cells was significantly lower in PB than in BM, not only for total progenitor cells but also for mature and immature progenitor cells, and the difference was found for granulocytic and particularly for erythroid lineages. The lower adhesion capacity of PB CD34+ cells to stroma was associated with decreased expression (signal/noise MFI ratio) of integrin alpha 4, beta 1, alpha L, and beta 2 chains whereas that of alpha 5 chain did not differ from BM cells with the lowest expression level. Similar differences in integrin expression levels were also found between mobilized PB and steady-state BM CD34+ cells in the same patient except for the alpha L chain. Moreover, we demonstrated for the first time a strong positive correlation between mobilizing capacity and expression levels on mobilized CD34+ cells for the LFA-1 alpha L chain but not for VLA-4 or VLA-5. In conclusion, the decreased adhesion capacity of mobilized PB progenitor cells to stroma involves different maturation stages and different lineages. This is associated with down-regulation of integrins VLA-4 and LFA-1, but mobilizing capacity appears positively correlated with LFA-1 levels.     

Interferon-alpha restores normal adhesion of chronic myelogenous leukemia hematopoietic progenitors to bone marrow stroma by correcting impaired beta 1 integrin receptor function.

Treatment of chronic myelogenous leukemia (CML) with interferon-alpha frequently results in normalization of peripheral blood counts and, in up to 20% of patients, reestablishment of normal hematopoiesis. We hypothesize that interferon-alpha may restore normal adhesive interactions between CML progenitors and the bone marrow microenvironment and restore normal growth regulatory effects resulting from these progenitor-stroma interactions. We demonstrate that treatment with interferon-alpha induces a significant, dose-dependent increase in the adhesion of primitive long-term culture initiating cells and committed colony-forming cells (CFC) from CML bone marrow to normal stroma. Adhesion of CFC seen after interferon-alpha treatment could be inhibited by blocking antibodies directed at the alpha 4, alpha 5, and beta 1 integrins and vascular cell adhesion molecule, but not CD44 or intracellular adhesion molecule, suggesting that interferon-alpha induces normalization of progenitor-stroma interactions in CML. Because FACS analysis showed that the level of alpha 4, alpha 5, and beta 1 integrin expression after interferon-alpha treatment is unchanged, this suggests that interferon-alpha may restore normal beta 1 integrin function. Normalization of interactions between CML progenitors and the bone marrow microenvironment may then result in the restoration of normal regulation of CML progenitor proliferation, and explain, at least in part, the therapeutic efficacy of interferon-alpha in CML.     

大鼠骨髓间充质干细胞血管细胞黏附分子1及细胞间黏附分子1的表达(英文)

背景:骨髓间充质干细胞系统性输注后,何种因素促使其迁移到正确部位尤为关键,目前认为黏附分子在介导骨髓间充质干细胞向缺血或损伤组织迁移过程中起重要作用.目的:观察血管细胞黏附分子1与细胞间黏附分子1在大鼠骨髓间充质干细胞中的表达.方法:采用直接贴壁法体外分离培养大鼠骨髓间充质干细胞,免疫细胞化学染色检测血管细胞黏附分子1及细胞间黏附分子1蛋白的表达,应用免疫荧光直标法在流式细胞仪上检测血管细胞黏附分子1及细胞间黏附分子1抗原的表达率,RT-PCR半定量分析血管细胞黏附分子1及细胞间黏附分子1 mRNA的表达.结果与结论:免疫细胞化学染色结果显示,骨髓间充质干细胞血管细胞黏附分子1呈弱阳性表达,细胞间黏附分子1呈强阳性表达.流式细胞仪检测结果显示,血管细胞黏附分子1表达率为6%,细胞间黏附分子1表达率为100%.RT-PCR检测结果显示,血管细胞黏附分子1 mRNA呈微弱表达,细胞间黏附分子1 mRNA呈高度表达.提示在生理状态下,体外培养的大鼠骨髓间充质干细胞低表达血管细胞黏附分子1,高表达细胞间黏附分子1.     

体外培养慢性粒细胞白血病患者骨髓间充质干细胞的生物学特性

背景:课题组从胎儿骨髓间充质干细胞的培养体系中鉴定出一类贴壁细胞,已证实此类细胞在单细胞水平可以向造血及内皮细胞分化.目的:检测骨髓间充质干细胞的生物学特性,为慢性粒细胞白血病的治疗提供相关的依据.方法:以慢性粒细胞白血病患者骨髓为研究对象,体外培养并扩增原始间充质干细胞,检测其BCR/ABL融合基因的表达、免疫学特性和生长曲线,使用RT-PCR和FISH的方法检测其BCR/ABL融合基因的表达情况.结果与结论:慢性粒细胞白血病患者骨髓来源的间充质干细胞呈成纤维样生长,大部分细胞处于G0/G1期,并且高表达Flk1,CD13,CD29,CD44,用RT-PCR和FISH的方法能够检测出BCR/ABL融合基因的表达.提示慢性粒细胞白血病的白血病基因转化可能发生在比造血干细胞更高的骨髓间充质干细胞水平上,对慢性粒细胞白血病的疾病起源及干细胞移植治疗有重要的意义.     

T lymphocyte differentiation in vitro from adult human prethymic CD34+ bone marrow cells

Pluripotent lymphohematopoietic stem cells are probably confined to bone marrow cells expressing CD34 surface molecules. To investigate the capacity of adult human CD34+ bone marrow cells to differentiate along the T lymphoid lineage, we plated purified CD34+ cells from healthy adults in liquid culture on adherent thymic stromal cells prepared from HLA- or blood group-mismatched postnatal thymic tissue. We show that purified CD34+CD3-CD4-CD8- bone marrow cells contained progenitors with the ability to differentiate into CD4+ and CD8+ T lymphocytes expressing surface (s)CD3 and T cell receptor alpha/beta in vitro. These progenitors were found in the CD34+CD2+sCD3-CD4-CD8-, CD34+CD7+sCD3-CD4-CD8-, and CD34+CD2+CD7+sCD3-CD4-CD8-, as well as in the CD34+CD2-sCD3-CD4-CD8-, CD34+CD7-sCD3-CD4-CD8-, and CD34+CD2-CD7- sCD3-CD4-CD8- subsets, indicating that T lymphocyte progenitors sensitive to signals mediated by thymic stroma in vitro are not restricted to CD34+ cells already coexpressing early T lymphocyte- associated markers. Finally, we show that T lymphopoiesis was enhanced by c-kit ligand.     

Treatment of marrow stroma with interferon-alpha restores normal beta 1 integrin-dependent adhesion of chronic myelogenous leukemia hematopoietic progenitors. Role of MIP-1 alpha.

The mechanisms by which interferon-alpha (IFN-alpha) restores normal hematopoiesis in chronic myelogenous leukemia (CML) are not well understood. We have recently demonstrated that IFN-alpha acts directly on CML hematopoietic progenitors to restore their adhesion to marrow stroma by modulating beta 1 integrin receptor function. In the present study we examined the effect of IFN-alpha treatment of marrow stroma on subsequent adhesion of CML progenitors. Stromal layers were preincubated with IFN-alpha (10,000 microns/ml) for 48 h. Subsequent coincubation with CML progenitors for 2 h resulted in significantly increased adhesion of CML progenitors. We demonstrated that alpha 4 beta 1 and alpha 5 beta 1 integrin receptors were involved in the enhanced adhesion of CML progenitors, suggesting that IFN-alpha-treated stroma can upregulate CML integrin function. This effect is due, at least in part, to IFN-alpha-induced increased stromal production of the chemokine macrophage inflammatory protein-1 alpha (MIP-1 alpha), which upregulates beta 1 integrin-dependent adhesion of CML progenitors to stroma. Thus, IFN-alpha treatment of marrow stroma restores beta 1 integrin-dependent adhesion of CML progenitors, at least in part through induction of MIP-1 alpha production. These observations provide further insights into mechanisms by which IFN-alpha may restore normal hematopoiesis in CML.     

Direct adhesion to bone marrow stroma via fibronectin receptors inhibits hematopoietic progenitor proliferation.

In long-term bone marrow cultures, stroma-adherent progenitors proliferate significantly less than nonadherent progenitors. Thus, close progenitor-stroma interactions may serve to regulate or restrict rather than promote hematopoietic progenitor proliferation. We hypothesized that signaling through adhesion receptors on hematopoietic cells may contribute to the inhibition of proliferation observed when progenitors are in contact with stroma. We demonstrate that progenitors cultured physically separated from stroma in a transwell proliferate significantly more than progenitors adherent to stroma. Furthermore, proliferation of colony forming cells (CFC) is reduced after specific adhesion to stroma, metabolically inactivated glutaraldehyde-fixed stroma, stromal-extracellular matrix, or the COOH-terminal heparin-binding domain of fibronectin. Nonspecific adhesion to poly-L-lysine fails to inhibit CFC proliferation. That the VLA-4 integrin is one of the receptors that transfers proliferation inhibitory signals was shown using blocking anti-alpha 4 monomeric F(ab) fragments. Furthermore, when synthetic peptides representing specific cell attachment sites within the heparin-binding domain of fibronectin were added to Dexter-type marrow cultures, significantly increased recovery and proliferation of CFC was observed, suggesting that these peptides disrupt adhesion-mediated proliferation inhibitory events. Thus, negative regulation of hematopoiesis may not only depend on the action of growth inhibitory cytokines but also on growth inhibitory signals resulting from direct adhesive interactions between progenitors and marrow stroma.     

多药耐药基因在人骨髓CD34+细胞中的表达及对化疗药物的耐受性

目的　探讨人多药耐药 (MDR1)基因过表达能否提高骨髓造血干 /祖细胞对化疗药物的耐受性。方法　应用免疫磁性分选系统 (miniMACS)体外分离、纯化骨髓CD34 细胞并进行扩增 ;采用脂质体介导的基因转移方法 ,将人MDR1基因转染骨髓CD34 细胞 ,并运用流式细胞术检测基因转导前后造血干 /祖细胞中MDR1基因的编码产物 Pl70糖蛋白表达和功能变化。MTT法检测基因转导前后造血干 /祖细胞对化疗药物耐受性的改变。结果　MDR1基因转导后 4 8h骨髓造血干 /祖细胞Pl70抗原表达为 (2 3 6± 2 34) % ,明显高于转导前 (11 2± 2 2 ) % (P <0 0 1)。P170的功能活性被Rh 12 3的摄取和排除试验证实。转基因后细胞表现为典型的多药耐药表型 ,对P170谱的多种化疗药的耐受性提高了约 2～ 8倍 ,对非P170谱的顺铂、氨甲喋呤耐受性没有改变。结论　人多药耐药基因能提高骨髓造血干 /祖细胞对多种化疗药物的耐受性 ,表现为典型的多药耐药表型。     

细胞因子在CD34阳性骨髓细胞中的表达

CD34~ 细胞包含有造血干/祖细胞,而造血干/祖细胞能被IL-3,GM-SCF,G-CSF等诱导分化与增殖。正常的CD34~ 细胞是否参与一些细胞因子的产生尚未被阐明。我们采用逆转录-聚合酶链反应分析了经流式细胞仪分选出的正常骨髓CD34~ 细胞IL-1β,IL-3,IL-4,IL-6,GM-CSF,TNF-α,TNF-β及c-kit基因的表达,并且分析了重组IL-1β,IL-3,IL-7,GM-CSF,PIXY321(IL-3/GM-CSF融合蛋白)及干细胞因子(SCF)对这些细胞因子的调节作用。结果发现新分选出的CD34~ 细胞表达较高水平的IL-1β,c-kit mRNA及低水平的IL-3,TNF-α,TNF-βmRNA。经外源性的细胞因子刺激后,IL-1β,TNF-α及TNF-βmRNA均有不同程度的上调,唯IL-7能使GM-CSF mRNA的表达变为阳性,IL-7亦能显著增强IL-6基因的表达。所有这些细胞因子对c-kit及IL-3基因表达均无明显作用。     

人正常骨髓CD34＋造因细胞的形态学与细胞化学特征

OBJECTIVE: To explore the cytomorphological and cytochemitry features of CD34+ hematopoietic cells. METHODS: Highly purified CD34+ hematopoietic cells isolated from human bone marrow by a two-step method of immunomagnetic beads-FACS sorting were comprehensively examined. RESULTS AND CONCLUSION: CD34+ hematopoietic cells could be sorted into three types in light of morphology and cytochemical staining. Type I was considered as candidates for stem cells,which were most blastlike in morphology and slightly larger than lymphocytes in size with negative reactions to all cytochemical stainings. Type II was considered as multipotent progenitor cells, with sizes similar to small lymphocytes and negative reactions to all cytochemical stainings. Type III was identified as committed progenitor cells whose sizes were heterogeneous and whose reactions to cytochemical stainings ranged from +/- to + +.     

正常人骨髓、脐血及动员后外周血CD^＋34细胞粘附分子的研究

目的探讨正常人骨髓、脐血及动员后外周血CD34+细胞粘附分子的表达及外周血干细胞动员的可能机制.方法采用CD34+MultiSortKit免疫磁珠分离系统,分离纯化出正常人骨髓、脐血及动员后外周血CD34+细胞,流式细胞术检测其纯度,选择与CD34+细胞相关的粘附分子CD44、CD11a、CD18、CD49d、CD54、CD58及CD62L,进行免疫荧光标记及短期液体培养后再行免疫荧光标记,流式细胞术检测.结果动员后外周血CD34+细胞粘附分子表达CD44为(92.7±2.2)%[骨髓(93.1±2.3)%]、CD11a为(56.3±6.0)%[骨髓(61.8±7.8)%]、CD18为(65.2±6.0)%[骨髓(70.6±7.5)%]、CD49d为(39.4±7.2)%[骨髓(66.9±5.1)%]、CD54为(20.9±4.1)%[骨髓(24.1±3.8)%]、CD58为(77.9±5.8)%[骨髓(81.9±5.6)%]及CD62L为(45.9±5.6)%[骨髓(63.9±4.3)%],其表达均较骨髓为低,尤以CD49d和CD62L为著.脐血CD34+细胞CD11a为(55.5±6.5)%、CD18为(66.7±7.5)%、CD44为(90.3±4.0)%、CD49d为(63.7±6.7)%、CD62L为(50.8±5.9)%,其表达亦较骨髓为低,尤以CD62L为著,但脐血CD54的表达[(29.1±4.9)%]较骨髓及动员后外周血为高,尤较动员后外周血为著.结论不同来源CD34+细胞粘附分子表达存在差异,外周血细胞动员的机制可能与粘附分子的表达下调有关.     

腺病毒介导的人骨形态发生蛋白2基因转染骨髓间充质干细胞

背景：骨髓间充质干细胞作为骨、软骨创伤缺损及退变修复的种子细胞越来越受到关注。目的：分析人骨形态发生蛋白2基因转染对白色封闭群大鼠（SD大鼠）骨髓间充质干细胞的影响。方法：分离纯化SD大鼠骨髓间充质干细胞并体外扩增,通过腺病毒载体介导人骨形态发生蛋白2基因转染骨髓间充质干细胞,分别通过荧光显微镜观察荧光表达情况及蛋白质水平来测定转染后人骨形态发生蛋白2的表达,碱性磷酸酶定量测定鉴定成骨活性及MTT法评估人骨形态发生蛋白2转染对骨髓间充质干细胞的影响。结果与结论：从SD大鼠骨髓提取物中分离培养的细胞形态为梭形,呈铺路石状、漩涡状生长,经流式细胞仪检测及多项分化能力鉴定符合骨髓间充质干细胞的特征;经转染人骨形态发生蛋白2基因后,骨髓间充质干细胞表达人骨形态发生蛋白2、碱性磷酸酶;MTT法检测转染人骨形态发生蛋白2基因后,骨髓间充质干细胞增殖能力明显增强（P〈0．05）。说明人骨形态发生蛋白2基因转染骨髓间充质干细胞后可以持续、高效表达入骨形态发生蛋白2和碱性磷酸酶,在体外明显促进骨髓间充质干细胞的增殖。