骨髓间充质干细胞对脐血CD34+细胞分化为巨核细胞的影响

目的：探讨骨髓间充质干细胞对脐血CD34＋细胞诱导分化为巨核细胞的影响。方法：骨髓间充质干细胞培养采用低糖型DMEM培养基,待细胞满度达到约80%后加入脐血CD34＋细胞在一定的培养体系中进行实验,同时以无骨髓间充质干细胞的相应培养体系作为对照,培养14 d后观察结果。实验中共观察了两种不同的培养体系：基础培养液、基础培养液＋白细胞介素-11（IL-11）。其中基础培养液为含血小板生成素（TPO）、白细胞介素-3（IL-3）、干细胞因子（SCF）的低糖型DMEM。培养后单个核细胞数采用细胞计数仪分析,CD41＋细胞和血小板检测采用流式细胞仪,血小板功能评价采用凝血酶诱导的血小板凝集实验。结果：与相应的对照组比较,骨髓间充质干细胞实验组单个核细胞数增加不明显（P〉0.05）,而CD41＋细胞和血小板数量有明显的增加（P〈0.05）。显微镜下和流式细胞仪上均可观察到凝血酶诱导的血小板凝集现象。结论：骨髓间充质干细胞在实验培养体系中可以促进脐血中CD34＋细胞诱导分化为巨核细胞。     

Functional properties of cells obtained from human cord blood CD34+ stem cells and mouse cardiac myocytes in coculture

Prior in vitro studies suggested that different types of hematopoietic stem cells may differentiate into cardiomyocytes. The present work examined whether human CD34(+) cells from the human umbilical cord blood (hUCB), cocultured with neonatal mouse cardiomyocytes, acquire the functional properties of myocardial cells and express human cardiac genes. hUCB CD34(+) cells were cocultured onto cardiomyocytes following an infection with a lentivirus-encoding enhanced green fluorescent protein (EGFP). After 7 days, mononucleated EGFP(+) cells were tested for their electrophysiological features by patch clamp and for cytosolic [Ca(2+)] ([Ca(2+)](i)) homeostasis by [Ca(2+)](i) imaging of X-rhod1-loaded cells. Human Nkx2.5 and GATA-4 expression was examined in cocultured cell populations by real-time RT-PCR. EGFP(+) cells were connected to surrounding cells by gap junctions, acquired electrophysiological properties similar to those of cardiomyocytes, and showed action potential-associated [Ca(2+)](i) transients. These cells also exhibited spontaneous sarcoplasmic reticulum [Ca(2+)](i) oscillations and the associated membrane potential depolarization. However, RT-PCR of both cell populations showed no upregulation of human-specific cardiac genes. In conclusion, under our experimental conditions, hUCB CD34(+) cells cocultured with murine cardiomyocytes formed cells that exhibited excitation-contraction coupling features similar to those of cardiomyocytes. However, the expression of human-specific cardiac genes was undetectable by RT-PCR.     

Peripheral blood and BM CD34+ CD38- cells show better resistance to cryopreservation than CD34+ CD38+ cells in autologous stem cell transplantation

BACKGROUND: We and others have shown a critical role for CD34+ CD38- cells in hematopoietic recovery after autologous stem cell transplantation (ASCT), in particular for platelet reconstitution. Thus a routine assessment of CD34+ CD38- cells in freezing-thawing procedures for autografting could represent an important tool for predicting poor engraftment. METHODS: To compare the impact of cryopreservation on CD34+ CD38+ and CD34+ CD38- hematopoietic stem cell subsets, 193 autograft products collected in 84 patients with malignancies were assessed before controlled-rate cryopreservation in 10% DMSO and after thawing for autografting. RESULTS: Cell counts after thawing were significantly different from the pre-freezing counts for total CD34+ (P<0.0001) and CD34+ CD38+ (P<0.0001) cells, but not for CD34+ CD38- cells (P=0.252). Median losses for CD34+, CD34+ CD38+ and CD34+ CD38- cells were, respectively, 11.8%, 11.4% and 0.0%. The magnitude of fresh/post-thawing percentage cell variation was significantly different when comparing between the CD34+ CD38+ and CD34+ CD38- cell subsets (P<0.001). Moreover, CD34+ CD38- cells exhibited recovery values > or =100% in 85/160 graft products, compared with 51/193 in CD34+ CD38+ cells (P<0.0001). Also, recovery values > or =90% were significantly better in the CD34+ CD38- (98/160 grafts) than in the CD34+ CD38+ subsets (89/193 grafts) (P<0.01). DISCUSSION: In this work we have demonstrated that CD34+ cells that do not express the CD38 Ag show a significantly better resistance to cryopreservation. This could represent another example of the particular ability of less committed progenitor cells to overcome environmental injuries. Moreover, we consider routine assessment of CD34+ CD38- cells before freezing as clinically relevant, but post-thawing controls may be avoided because of their good resistance to freezing.     

Intrahepatic transplantation of CD34+ cord blood stem cells into newborn and adult NOD/SCID mice induce differential organ engraftment

In vivo studies concerning the function of human hematopoietic stem cells (HSC) are limited by relatively low levels of engraftment and the failure of the engrafted HSC preparations to differentiate into functional immune cells after systemic application. In the present paper we describe the effect of intrahepatically transplanted CD34⁺ cells from cord blood into the liver of newborn or adult NOD/SCID mice on organ engraftment and differentiation.Analyzing the short and long term time dependency of human cell recruitment into mouse organs after cell transplantation in the liver of newborn and adult NOD/SCID mice by RT-PCR and FACS analysis, a significantly high engraftment was found after transplantation into liver of newborn NOD/SCID mice compared to adult mice, with the highest level of 35% human cells in bone marrow and 4.9% human cells in spleen at day 70. These human cells showed CD19 B-cell, CD34 and CD38 hematopoietic and CD33 myeloid cell differentiation, but lacked any T-cell differentiation. HSC transplantation into liver of adult NOD/SCID mice resulted in minor recruitment of human cells from mouse liver to other mouse organs. The results indicate the usefulness of the intrahepatic application route into the liver of newborn NOD/SCID mice for the investigation of hematopoietic differentiation potential of CD34⁺ cord blood stem cell preparations.     

Endothelial cells from cord blood CD133+CD34+ progenitors share phenotypic, functional and gene expression profile similarities with lymphatics

The existence of endothelial progenitor cells (EPC) with high cell-cycle rate in human umbilical cord blood has been recently shown and represents a challenging strategy for therapeutic neovascularization. To enhance knowledge for future cellular therapy, we compared the phenotypic, functional and gene expression differences between EPC-derived cells generated from cord blood CD34⁺ cells, and lymphatic and macrovascular endothelial cells (EC) isolated from human foreskins and umbilical veins, respectively. Under appropriate culture conditions, EPC developed into fully matured EC with expression of similar endothelial markers as lymphatic and macrovascular EC, including CD31, CD36, von Willebrand factor FVIII, CD54 (ICAM-1), CD105 (endoglin), CD144 (VE-cadherin), Tie-1, Tie-2, VEGFR-1/Flt-1 and VEGFR-2/Flk-1. Few EPC-derived cells became positive for LYVE-1, indicating their origin from haematopoietic stem cells. However they lacked expression of other lymphatic cell-specific markers such as podoplanin and Prox-1. Functional tests demonstrated that the cobblestone EPC-derived cells up-regulated CD54 and CD62E expression in response to TNF-α, incorporated DiI-acetylated low-density liproprotein and formed cord- and tubular-like structures with capillary lumen in three-dimensional collagen culture – all characteristic features of the vascular endothelium. Structures compatible with Weibel-Palade bodies were also found by electron microscopy. Gene microarray profiling revealed that only a small percentage of genes investigated showed differential expression in EPC-derived cells and lymphatic EC. Among them were adhesion molecules, extracellular matrix proteins and cytokines. Our data point to the close lineage relationship of both types of vascular cells and support the theory of a venous origin of the lymphatic system.     

脂质体介导反义核酸对乳腺癌MCF-7细胞增殖的影响

目的:探讨脂质体LipfectAMINETM介导c-myc反义寡核苷酸(ASODN)对MCF-7细胞增殖的影响.方法:MCF-7细胞分五组处理:c-mycSODNs组、LR/c-mycSODNs组、c-mycASODNs组、LR/c-mycASODNs组、LR组和空白对照组.以MTT法检测72h各处理组细胞增殖的情况;以免疫细胞化学ABC法检测LR/c-mycASODNs组转染前后细胞中c-myc蛋白的表达.结果:c-mycASODNs组(0.383±0.015)和LR/c-mycASODNs组(0.178±0.015)均能明显抑制细胞生长,差异具有显著性(P＜0.01),且后者对细胞的生长抑制率(73.13%)明显高于前者(17.47%):LR/c-mycASODNs组免疫细胞化学显示c-myc蛋白表达明显降低.结论:LR介导的c-mycASODN能明显抑制MCF-7细胞生长和c-myc蛋白表达.     

Initial cord blood unit volume affects mononuclear cell and CD34+ cell-processing efficiency in a non-linear fashion

Background aimsUmbilical cord blood (UCB) is a source of hematopoietic stem cells that initially was used exclusively for the hematopoietic reconstitution of pediatric patients. It is now suggested for use for adults as well, a fact that increases the pressure to obtain units with high cellularity. Therefore, the optimization of UCB processing is a priority.MethodsThe present study focused on parameters influencing total nucleated cell (TNC), mononucleated cell (MNC) and CD34 ⁺ cell (CD34C) recovery after routine volume reduction of 1553 UCB units using hydroxyethyl starch-induced sedimentation with an automated device, under routine laboratory conditions.ResultsWe show that the unit volume rather than the TNC count significantly affects TNC, MNC and CD34C processing efficiency (PEf), and this in a non-linear fashion: when units were sampled according to the collection volume, including pre-loaded anticoagulant (gross volume), PEf increased up to a unit volume of 110–150 mL and decreased thereafter. Thus units with initial gross volumes < 90 mL and > 170 mL similarly exhibited a poor PEf.ConclusionsThese data identify unit gross volume as a major parameter influencing PEf and suggest that fractionation of large units should be contemplated only when the resulting volume of split units is > 90 mL.     

CD34+ stem cells in chronic myeloproliferative disorders

Contrasting the wealth of information that is available about various biological and therapeutic aspects of human CD34+ stem cells, little data exist concerning their quantity and dynamics as well as their mutual relationships with other hematopoietic constituents in the bone marrow of patients with chronic myeloproliferative disorders. In comparison with a control group frequency of progenitors is significantly increased in chronic myeloid leukemia (CML). Following different therapeutic modalities their quantity reflects therapeutic efficacy (responder and non-responder patients) and therefore exerts a predictive value regarding acceleration and blastic crisis. The significant correlations between fiber content and number of these precursors elucidates the complex interactions between stroma and progenitor cell differentiation and maturation. Following allogeneic bone marrow transplantation there is a rapid recovery of the CD34+ stem cell population in the first month. A higher number of these cells is related with graft size, an earlier independence for platelet transfusion and a more extended regeneration of erythro- and megakaryopoiesis. The slight increase in reticulin fibers in these patients may be associated with the complex and so far ill-defined pathomechanism of homing (adherence to the fibrous matrix). In idiopathic myelofibrosis (IMF) an increased number of CD34+ stem cells is found predominantly in the early (prefibrotic or mild fibrotic) hypercellular stages and probably indicates a higher proliferative activity of the precursor cell pool. According to sequential biopsies most patients with early IMF that later evolved into an overt fibrosclerotic stage usually display a reduction of progenitor cells during the development of myelofibrosis. The unequal distribution of CD34+ stem cells in the bone marrow versus spleen in IMF (advanced fibrosclerotic stage) is in support of the currently discussed hypothesis of splenic filtration and concentration of precursor cells as an essential feature of myeloid metaplasia. Regarding prognosis in CML a higher amount of CD34+ stem cells is significantly associated with an unfavorable survival and thus confirms the assumed implication of an accelerated phase of disease at onset. On the other hand, in polycythemia vera (PV) and IMF a low number of progenitors is probably due to a decreased proliferation rate (reduced hematopoietic turnover index) and therefore reflects a reduction in the regenerative capacity of hematopoiesis. For this reason, a presumptive defect in the recovery of normal and clonally transformed stem cells is speculated to add to the worsening of prognosis by causing the well-known bone marrow insufficiency in terminal stage PV and IMF.     

Hematopoietic reconstitution of CD34+ cells derived from short-term cultured cord blood mononuclear cells

Ex vivo expansion of hematopoietic stem cells (HSCs) is very important for clinical applications of cord blood (CB). With the aim to find proper culture duration for ex vivo expansion, mononuclear cells (MNC) was applied as starting culture cells to expand HSCs and the repopulating potential of seven-day and fourteen-day cultured CD34⁺ cells were compared. The average expansion of total cells and CD34⁺ cells cultured for 7 days were higher than those cultured for 14 days. The results of phenotypic analysis of fresh and cultured cells showed that the percentage of CD3⁺ cells declined and the percentage of CD33⁺ cells increased during culture. The engraftment levels of fourteen-day cultured CD34⁺ cells were higher than those of fresh and seven-day cultured CD34⁺ cells. Fourteen-day cultured CD34⁺ cells also showed better multilineage reconstitution ability than fresh and seven-day cultured CD34⁺ cells. The results of the present study demonstrated that prolonged culture could preserve the hematopoietic reconstitution ability of ex vivo cultured CB cells and improve the engraftment level in NOD/SCID mice.     

Mesenchymal stem cells promote a primitive phenotype CD34+c-kit+ in human cord blood-derived hematopoietic stem cells during ex vivo expansion

The purpose of this study was to evaluate the influence of bone marrow-mesenchymal stem cells (BM-MSC) and exogenously added cytokines on the proliferation, primitive cell subpopulation maintenance (including the c-kit+ marker) and clonogenic capacity of hematopoietic stem cells (HSC). BM-MSC were collected from volunteer donors, isolated and characterized. Umbilical cord blood (UCB) samples were collected from healthy full-term deliveries. UCB-CD34+ cells were cultured in the presence or absence of BM-MSC and/or cytokines for 3 and 7 days. CD34+ cell proliferation was evaluated using the CSFE method and cell phenotype was determined by CD34, c-kit, CD33, CD38, HLA-DR, cyCD22 and cyCD3 detection. Cell clonogenic ability was also assessed. Exogenously added SCF, TPO and FLT3L increasedCD34+ cell proliferation in the presence or absence of BM-MSC, but with concomitant cell differentiation. Without any added cytokines, BM-MSC are able to increase the percentage of primitive progenitors as evaluated by c-kit expression and CFU-GEMM increase. Interestingly, this latter effect was dependent on both cell-cell interactions and secreted factors. A 7-day co-culture period will be optimal for obtaining an increased primitive HSC level. Including c-kit as a marker for primitive phenotype evaluation has shown the relevance of BM-MSC and their secreted factors on UCB-HSC stemness function. This effect could be dissociated from that of the addition of exogenous cytokines, which induced cellular differentiation instead.     

Hyperbaric oxygen treatment effects on in vitro cultured umbilical cord blood CD34+ cells

Background aims

Umbilical cord blood (UCB) provides an alternative source for hematopoietic stem/progenitor cells (HSPCs) in the treatment of hematological malignancies. However, clinical usage is limited due to the low quantity of HSPCs in each unit of cord blood and defects in bone marrow homing. Hyperbaric oxygen (HBO) is among the more recently explored methods used to improve UCB homing and engraftment. HBO works by lowering the host erythropoietin before UCB infusion to facilitate UCB HSPC homing, because such UCB cells are not directly exposed to HBO. In this study, we examined how direct treatment of UCB-CD34⁺ cells with HBO influences their differentiation, proliferation and in vitro transmigration.

Placental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells support hematopoietic recovery of X-irradiated human CD34+ cells

AimsThe potential of human mesenchymal stem cell-like stroma prepared from placental/umbilical cord blood for hematopoietic regeneration by X-irradiated hematopoietic stem cells is herein assessed.Main methodsPlacental/umbilical cord blood-derived mesenchymal stem cell-like stromal cells were applied to a regenerative ex vivo expansion of X-irradiated human CD34⁺ cells in a serum-free liquid culture supplemented with a combination of interleukine-3 plus stem cell factor plus thrombopoietin.Key findingsThe total number of cells and of lineage-committed myeloid hematopoietic progenitor cells generated in the co-culture of both non-irradiated and X-irradiated cells with stromal cells was significantly higher than those in the stroma-free culture. In addition, the number of CD34⁺ cells and CD34⁺/CD38^? cells, immature hematopoietic stem/progenitor cells also increased more than the stroma-free culture. The stromal cells produced various types of cytokines, although there was little difference between the co-cultures of non-irradiated and X-irradiated cells with stromal cells. Furthermore, when X-irradiated cells came in contact with stromal cells for 16 h before cytokine stimulation, a similar degree of hematopoiesis was observed, thus suggesting the critical role of cell-to-cell interaction.SignificanceThe present results showed the potential efficacy of human mesenchymal stem cell-like stroma for hematopoietic regeneration from irradiated hematopoietic stem/progenitor cells.     

Multi-laboratory assay for harmonization of enumeration of viable CD34+ and CD45+ cells in frozen cord blood units

Background aimsIn 2016, specifications for both pre-cryopreserved and post-thawed cord blood were defined in the sixth edition of NetCord Foundation for the Accreditation of Cellular Therapy (FACT) Standards for Cord Blood Banks. However, for several experts, harmonization regarding flow cytometry analysis performed on post-thawed samples is still a concern. A multicenter study led by Héma-Québec aimed to provide scientific data to support the cord blood accreditation bodies such as NetCord FACT in the revision of standards.MethodsTwelve cord blood units were processed for plasma and red cell reduction following standard operating procedures. Cord blood unit aliquots were shipped to eight participating centers under cryogenic conditions for analysis before and after standardization of protocol. Repeatability of stem cell count, measured pre- and post-intervention with the centers, was estimated using multilevel linear regression models with a heterogeneous compound symmetry correlation structure among repeated measures.ResultsExcellent inter-center repeatability was reported by each participant regarding the viable CD34+ cells concentration, and a successful improvement effect of protocol standardization was also observed. However, we observed that better control over the critical parameters of the protocol did not have a significant effect on improving homogeneity in the enumeration of CD45+ cells.ConclusionsThe current practice in cord blood selection should now also consider relying on post-thaw CD34+ concentration, providing that all cord blood banks or outsourcing laboratories in charge of the analysis of post-thaw CB samples take into account the consensual recommendations provided in this work and adhere to a good-quality management system.     

Initial CD34+ cell-enrichment of cord blood determines hematopoietic stem/progenitor cell yield upon ex vivo expansion

Since umbilical cord blood (UCB), contains a limited hematopoietic stem/progenitor cells (HSC) number, successful expansion protocols are needed to overcome the hurdles associated with inadequate numbers of HSC collected for transplantation. UCB cultures were performed using a human stromal‐based serum‐free culture system to evaluate the effect of different initial CD34⁺ cell enrichments (Low: 24 ± 1.8%, Medium: 46 ± 2.6%, and High: 91 ± 1.5%) on the culture dynamics and outcome of HSC expansion. By combining PKH tracking dye with CD34⁺ and CD34⁺CD90⁺ expression, we have identified early activation of CD34 expression on CD34^? cells in Low and Medium conditions, prior to cell division (35 ± 4.7% and 55 ± 4.1% CD34⁺ cells at day 1, respectively), affecting proliferation/cell cycle status and ultimately determining CD34⁺/CD34⁺CD90⁺ cell yield (High: 14 ± 1.0/3.5 ± 1.4‐fold; Medium:22 ± 2.0/3.4 ± 1,0‐fold; Low:31 ± 3.0/4.4 ± 1.5‐fold) after a 7‐day expansion. Considering the potential benefits of using expanded UCB HSC in transplantation, here we quantified in single UCB units, the impact of using one/two immunomagnetic sorting cycles (corresponding to Medium and High initial progenitor content), and the average CD34⁺ cell recovery for each strategy, on overall CD34⁺ cell expansion. The higher cell recovery upon one sorting cycle lead to higher CD34⁺ cell numbers after 7 days of expansion (30 ± 2.0 vs. 13 ± 1.0 × 10⁶ cells). In particular, a high (>90%) initial progenitor content was not mandatory to successfully expand HSC, since cell populations with moderate levels of enrichment readily increased CD34 expression ex‐vivo, generating higher stem/progenitor cell yields. Overall, our findings stress the importance of establishing a balance between the cell proliferative potential and cell recovery upon purification, towards the efficient and cost‐effective expansion of HSC for cellular therapy. J. Cell. Biochem. 112: 1822–1831, 2011. © 2011 Wiley‐Liss, Inc.     

Nicotine increases cancer stem cell population in MCF-7 cells

Epidemiological studies have suggested that cigarette smoking is related to increased breast cancer risk. Nicotine is most likely related to the risk in cigarette smoking. However, the mechanisms by which nicotine promotes cancer development are not fully understood. It has recently been suggested that development of breast cancer are originated from cancer stem cells, which are a minor population of breast cancer. In the present study, we investigated the effects of nicotine on the population of cancer stem cells in MCF-7 human breast cancer cells, using flow cytometry with a cancer stem cell marker aldehyde dehydrogenase (ALDH). We found that nicotine increased ALDH-positive cell population in a dose-dependent manner. We further demonstrated that a PKC-Notch pathway is involved in the effect of nicotine. In addition, the effect of nicotine was blocked by treatment with the α7 subunit-selective antagonist of nicotinic acetylcholine receptors (nAChR) α-Bungarotoxin. These data suggest that nicotine increases the stem cell population via α7-nAChR and the PKC-Notch dependent pathway in MCF-7 cells. These findings reveal a relationship between nicotine and the cancer stem cells in human breast cancer.     

Cytokine-pretreatment of CD34(+) cord blood stem cells in vitro reduces long-term cell engraftment in NOD/SCID mice

Stem cell homing, engraftment and organ regeneration are controlled by cytokines, chemokines and cell-cell interactions. In this paper, cytokine effects on homing- and engraftment-related characteristics of CD34(+) cord blood cells were examined. Untreated CD34(+) cells were mainly in the G(0)/G(1) cell cycle phase, expressed adhesion receptors on a low level, were positive for vimentin, and negative for the epithelial marker cytokeratin 8/18. Treatment with stem cell factor (SCF) stimulated cell proliferation, increased the number of cells in S and G(2)/M cell cycle phase as well as the expression of adhesion receptors. The expression of cytokeratin 8/18 was increased and that of vimentin remained unchanged. Hepatocyte growth factor (HGF) did not stimulate cell proliferation and expression of adhesion receptors, but increased expression of cytokeratin 8/18. In NOD/SCID mice, kinetics of stem cell distribution revealed a fast elimination of human cells from blood. An increase in the number of engrafted cells was observed in different mouse organs in a time-dependent manner, preferentially in bone marrow, spleen and liver. Pretreatment with SCF resulted in reduction of long-term engraftment in bone marrow. HGF pretreatment of cord blood cells showed no significant effects on long-term engraftment capacity in mouse organs compared to untreated cells. Our data provide in vivo evidence that pretreatment of CD34(+) cells with SCF reduces long-term cell engraftment in NOD/SCID mice.