间充质干细胞在造血干细胞移植中的应用

间充质干细胞是一种能够从各种人成体组织分离出来的非造血多能干细胞,近年来,许多研究表明间充质干细胞具有免疫调节能力及促进组织重建等功能.就其在造血干细胞移植中的应用,如急慢性移植物抗宿主病(GVHD)、GVHD造成的移植失败、纯红细胞再生障碍性贫血及免疫性血小板减少性紫癜、出血性膀胱炎作以综述.     

The role of blood stem cells in hematopoietic cell renewal

It has been the purpose of this keynote address to review available evidence for the notion that the stem and progenitor cells circulating in the peripheral blood play a decisive role in the homeostasis of blood cell formation distributed throughout dozens of bone marrow units in the skeleton. Furthermore, if this notion is correct, one could speculate that the quantity and quality of stem and progenitor cells in the blood should reflect the functional state of the hematopoietic stem cell system throughout the skeletal bone marrow and provide a new tool for the evaluation of alteration in blood cell production. On this basis, the following questions are considered: A) What do we know about the quality and quantity of blood stem cells in steady-state conditions? B) In what way do blood stem cells respond to perturbations of the "steady-state" of blood cell formation? C) Which role do blood stem cells play during hemopoietic development assuming that the establishment of bone marrow hemopoiesis requires the "seeding" of blood stem cells into an appropriate cellular environment? D) What is the role of blood stem cells in hemopoietic regeneration after partial body irradiation with a small volume of marrow (and hence stem cells) protected? and E) What are the mechanisms and/or kinetics of hemopoietic recovery if stem cells introduced into the circulation were collected from exogenous (autologous or allogeneic) sources? In this review presentation, experimental work of our group and of other members of the scientific community is summarized. It becomes obvious that blood stem and progenitor cells play a key role in hematopoietic homeostasis. Furthermore, their physiology and pathophysiology deserve rigorous experimental studies in order to develop a novel tool in the diagnosis and prognosis of neoplastic and non-neoplastic disorders of blood cell formation.     

Human growth factor-enhanced regeneration of transplantable human hematopoietic stem cells in nonobese diabetic/severe combined immunodeficient mice

Self-renewal is considered to be the essential defining property of a stem cell. Retroviral marking, in vitro amplification, and serial transplantation of human cells that can sustain long-term lymphomyelopoiesis in vivo have provided evidence that human hematopoietic stem cell self-renewal occurs both in vitro and in vivo. To investigate whether this process can be manipulated by cytokines, we administered two different combinations of human growth factors to sublethally irradiated nonobese diabetic/severe combined immunodeficient (SCID) mice transplanted with 10(7) light-density human cord blood cells and then performed secondary transplants to compare the number of transplantable human lymphomyeloid reconstituting cells present 4 to 6 weeks post-transplant. A 2-week course of Steel factor + interleukin (IL)-3 + granulocyte-macrophage colony-stimulating factor + erythropoietin (3 times per week just before sacrifice) specifically and significantly enhanced the numbers of transplantable human lymphomyeloid stem cells detectable in the primary mice (by a factor of 10). Steel factor + Flt3-ligand + IL-6 (using either the same schedule or administered daily until sacrifice 4 weeks post-transplant) gave a threefold enhancement of this population. These effects were obtained at a time when the regenerating human progenitor populations in such primary mice are known to be maximally cycling even in the absence of growth factor administration suggesting that the underlying mechanism may reflect an ability of these growth factors to alter the probability of differentiation of stem cells stimulated to proliferate in vivo.     

急性白血病患者造血干细胞P-选择素表达的研究

目的 研究急性白血病(AL)患者骨髓白血病干细胞表面分子P-选择素(CD62P)的表达情况及其临床意义.方法 采用流式细胞术(FCM)检测56例初治AL患者骨髓CD62P的表达情况,以15例健康成年人骨髓标本为对照.结果 38例急性髓系白血病(AML)患者干细胞(CD+45CD+34CD-38)中CD62P平均表达水平为(6.72±7.64)%,12例急性B淋巴细胞白血病(B-ALL)患者干细胞(CD+45CD+34CD+19)为(3.46±2.51)%,6例急性T淋巴细胞白血病(T-ALL)患者干细胞(CD+45 CD+34CD+7)为(6.23±4.95)%,均明显高于健康对照组[(1.04±1.23)%](t值分别为2.847、3.284、3.091,P＜0.01).经过正规方案治疗后,完全缓解组患者CD62P表达与健康对照差异无统计学意义(t=0.397,P＞0.05).另外CD+62P的AML及T-ALL患者白细胞计数、血红蛋白及血小板计数均明显高于CD-62P患者(t值分别为4.153、8.095、8.289、7.235、8.692、9.832,P＜0.05);而CD+62P与CD-62P的B-ALL患者无明显差异(t值分别为0.340、1.142、0.019,P＞0.05).结论 CD62P是血小板活化的标志物之一,在不同类型的AL中有不同程度的表达.AL骨髓造血干细胞中CD62P可能作为白血病造血干细胞的标志,以及临床疗效观察预后判断的指标之一.     

Reovirus-induced acute myocarditis in mice correlates with viral RNA synthesis rather than generation of infectious virus in cardiac myocytes

The capacity for different reovirus reassortant viruses to induce acute myocarditis in mice correlates with cytopathogenic effect in primary cultures of murine cardiac myocytes. Multiple viral genes encoding proteins involved in viral RNA synthesis are determinants of this disease. We therefore evaluated the role of viral RNA synthesis in induction of acute myocarditis by infecting primary cultures of cardiac myocytes with a panel of myocarditic and nonmyocarditic viruses and quantitating RNA synthesis. RNA synthesis correlated with induction of myocarditis and with the S1 and M1 reovirus genes. Since one consequence of viral RNA synthesis is generation of infectious virus, we looked next at viral yield from cardiac myocyte cultures. Yield of infectious virus at an early time postinfection or as a final yield from primary infections did not correlate with myocarditis, but instead both correlated with the S1 gene. The S1 gene also determined the fraction of cells infected during primary infections in the culture, which varied dramatically between viruses. Viral yields per infected cell were similar for most myocarditic and nonmyocarditic reoviruses and did not correlate with induction of myocarditis or any reovirus gene. Together, the data provide two insights into reovirus-induced acute myocarditis in mice. First, while the S1 gene. which encodes the viral attachment protein sigma1 (as well as a nonstructural protein, sigma1s, of unknown function) does not determine the myocarditic potential of these viruses, it does determine the efficiency with which they infect cardiac myocytes. Second, while viral RNA synthesis is a determinant of acute myocarditis, this is not due to generation of infectious virus. This finding suggests that some other consequence of viral RNA synthesis, for example, induction of interferon, may determine reovirus-induced acute myocarditis.     

Short- and long-term multilineage repopulating hematopoietic stem cells in late fetal and newborn mice: models for human umbilical cord blood

Blood from late fetal and newborn mice is similar to umbilical cord blood obtained at birth in human beings, an important source of stem cells for clinical transplantation. The mouse model is useful because long-term functions can be readily assayed in vivo. To evaluate the functions of hematopoietic precursors in the blood and other tissues of late fetal and newborn mice, short- and long-term multilineage repopulating abilities were measured in vivo by competitive repopulation. Manipulations that might affect cell function, such as enrichment, tissue culture, or retroviral marking, were avoided. Hematopoietic stem cell functions of late fetal or newborn blood, liver, and spleen, were assayed as myeloid and lymphoid repopulating abilities relative to standard adult marrow cells. Donor cells from these tissues as well as adult control donor marrow cells were all of the same genotype. Cells from each donor tissue were mixed with portions from a pool of standard adult "competitor" marrow distinguished from the donors by genetic differences in hemoglobin and glucosephosphate isomerase. After 21 to 413 days, percentages of donor type myeloid and lymphoid cells in recipient blood were measured to assay the functional abilities of donor precursors relative to the standard. These relative measures are expressed as repopulating units, where each unit is equivalent to the repopulating ability found in 100,000 standard adult marrow cells. Thus, measures of repopulating units do not compare single cells but overall repopulating abilities of donor cell populations. Relative functional abilities in 1 million nucleated cells from late fetal or newborn blood were several times less than those found in adult marrow, but far more than in normal adult blood, and appeared to include long-term functional primitive hematopoietic stem cells (PHSC) similar to those in marrow. To estimate functional abilities of individual PHSC, variances among large groups of identical recipients were analyzed using both the binomial model and competitive dilution, a new model based on the Poisson distribution. The data best fit the hypothesis that individual PHSC from adult marrow, late fetal blood, or newborn blood each produce similar fractions of the total lymphoid and erythroid cells found in the recipient for many months.     

Mature human hematopoietic cells in donor bone marrow complicate interpretation of stem/progenitor cell assays in xenogeneic hematopoietic chimeras

Xenogeneic hematopoietic chimeras have been used to assay the growth and differentiation of human stem/progenitor cells. The presence of human hematopoietic cells in immunodeficient mice transplanted with human marrow cells may be caused by proliferation and differentiation of early stem/progenitor cells and/or proliferation of mature cells. Unpurified human marrow mononuclear cells, T cell-depleted, or stem/progenitor cell-enriched (CD34+ or CD34+CD38-) populations were injected into sublethally irradiated NOD/LtSz scid/scid (NOD/SCID) mice. High levels of human cells were detected in mice (hu/mu chimeras) transplanted with each of the above human marrow populations. Large numbers of mature human T lymphocytes were found in marrow, spleens, and thymuses from hu/mu chimeras that had been transplanted with unpurified human mononuclear marrow cells. Human immunoglobulin was detected in sera from these chimeras, and some exhibited a clinical syndrome suggestive of graft-versus-host disease. In contrast, in hu/mu chimeras that had received T cell-depleted or stem/progenitor cell-enriched populations, multilineage hematopoiesis (myeloid, B lymphoid, and progenitor cells by immunophenotype) was detected but T lymphocytes and human immunoglobulin were not; in addition, no human cells were detected in the thymuses. Thus, injection of adult human marrow cells into immunodeficient mice can result in hematopoietic chimerism for at least 3 months after transplant. However, the types of cells present in hu/mu chimeras differ depending on the human cell population transplanted. This should be taken into account when hematopoietic chimeras are used to assess human stem/progenitor cell function.     

Evidence suggesting the involvement of hematopoietic stem cells in the pathogenesis of IgA nephropathy

To investigate the role of hematopoietic stem cells in the pathogenesis of IgA nephropathy, T-cell-depleted bone marrow cells for IgA nephropathy-prone ddY mice were transplanted into C57BL/6j (B6) mice pretreated with cyclophosphamide. In the 12th week after bone marrow transplantation, transplanted bone marrow cells had successfully regenerated. In B6 recipients of T-cell-depleted allogeneic bone marrow cells for ddY mice ([ddy-->B6]), mesangial IgA and C3 deposits were significantly more intense than those in B6 mice receiving syngeneic bone marrow cells of B6 mice ([B6-->B6]). The serum IgA level in [ddY-->B6] mice was higher than that in [B6-->B6] mice. Molecular profile analysis of serum IgA revealed that the serum concentration of macromolecular IgA was increased in [ddY-->B6], but not in [B6-->B6] mice. These data suggest that disorders programmed at the level of BMCs are involved in the pathogenesis of IgA nephropathy by increasing circulating levels of macromolecular IgA.     

Long-term repopulating ability of xenogeneic transplanted human fetal liver hematopoietic stem cells in sheep

We previously reported on the successful engraftment and long-term multilineage expression (erythroid, myeloid, lymphoid) of human fetal liver hematopoietic stem cells in sheep after transplantation in utero. That the engraftment of long-term repopulating pluripotent stem cells occurred in these animals was shown here by the fact that transplantation of human CD45+ cells isolated from bone marrow of these chimeric animals into preimmune fetal sheep resulted in engraftment and expression of human cells. Marrow cells were obtained from three chimeric sheep at 3.2-3.6 yr after transplant. The relative percentage of human CD45+ cells present in these marrows was 3.3 +/- 0.32%. A total of 29 x 10(6) CD45+ cells were isolated by panning, pooled, and transplanted into six preimmune sheep fetuses (4.8 x 10(6) cells/fetus). All six recipients were born alive. Hematopoietic progenitors exhibiting human karyotype were detected in marrows of two lambs soon after birth. Cells expressing human CD45 antigen were also detected in blood and marrow of both lambs. Human cell expression has been multilineage and has persisted for > 1 yr. These results demonstrate that the expression of human cells in this large animal model resulted from engraftment of long-term repopulating pluripotent human stem cells.     

Expansion in vitro of adult murine hematopoietic stem cells with transplantable lympho-myeloid reconstituting ability

Elucidation of mechanisms that regulate hematopoietic stem cell self-renewal and differentiation would be facilitated by the identification of defined culture conditions that allow these cells to be amplified. We now demonstrate a significant net increase (3-fold, P < 0.001) in vitro of cells that are individually able to permanently and competitively reconstitute the lymphoid and myeloid systems of syngeneic recipient mice when Sca-1(+)lin- adult marrow cells are incubated for 10 days in serum-free medium with interleukin 11, flt3-ligand, and Steel factor. Moreover, the culture-derived repopulating cells continued to expand their numbers in the primary hosts at the same rate seen in recipients of noncultured stem cells. In the expansion cultures, long-term culture-initiating cells increased 7- +/- 2-fold, myeloid colony-forming cells increased 140- +/- 36-fold, and total nucleated cells increased 230- +/- 62-fold. Twenty-seven of 100 cultures initiated with 15 Sca-1(+)lin- marrow cells were found to contain transplantable stem cells 10 days later. This frequency of positive cultures is the same as the frequency of transplantable stem cells in the original input suspension, suggesting that most had undergone at least one self-renewal division in vitro. No expansion of stem cells was seen when Sca-1+TER119- CD34+ day 14.5 fetal liver cells were cultured under the same conditions. These findings set the stage for further investigations of the mechanisms by which cytokine stimulation may elicit different outcomes in mitotically activated hematopoietic stem cells during ontogeny and in the adult.     

Effect of FLT3 ligand and granulocyte colony-stimulating factor on expansion and mobilization of facilitating cells and hematopoietic stem cells in mice: kinetics and repopulating potential

We have previously identified a cellular population in murine bone marrow that facilitates engraftment of highly purified hematopoietic stem cells (HSC) across major histocompatibility complex (MHC) barriers without causing graft-versus-host disease. Here we investigated the effect of flt3 ligand (FL) and granulocyte colony-stimulating factor (G-CSF) on the mobilization of facilitating cells (FC) and HSC into peripheral blood (PB). Mice were injected with FL alone (day 1 to 10), G-CSF alone (day 4 to 10), or both in combination. The number of FC (CD8(+)/alpha betaTCR-/gamma deltaTCR-) and HSC (lineage-/Sca-1(+)/c-kit+) was assessed daily by flow cytometry. Lethally irradiated allogeneic mice were reconstituted with PB mononuclear cells (PBMC). FL and G-CSF showed a highly significant synergy on the mobilization of FC and HSC. The peak efficiency for mobilization of FC (21-fold increase) and HSC (200-fold increase) was reached on day 10. Our data further suggest that the proliferation of FC and HSC induced by FL in addition to the mobilizing effect mediated by G-CSF might be responsible for the observed synergy of both growth factors. Finally, the engraftment potential of PBMC mobilized with FL and G-CSF or FL alone was superior to PBMC obtained from animals treated with G-CSF alone. Experiments comparing the engraftment potential of day 7 and day 10 mobilized PBMC indicate that day 10, during which both FC and HSC reached their maximum, might be the ideal time point for the collection of both populations.     

IL-2-activated murine newborn liver NK cells enhance engraftment of hematopoietic stem cells in MHC-mismatched recipients

To explore the modulatory effects of IL-2-activated NK cells on hematopoietic stem cell (HSC) engraftment further, we used fresh newborn liver cells (NLC) and IL-2-activated newborn liver cells (ANLC) as combined sources, respectively, of transplanted HSC and IL-2-activated NK cells free of contaminating CD3+ T cells. As previously found with adult IL-2-activated spleen cells, NLC cultured with IL-2 for 7 days exhibited lymphokine-activated killer (LAK) activity, veto activity, and natural suppressor activity, and enhanced both short-term and long-term stem cell engraftment by intact co-injected syngeneic and allogeneic NLC in totally MHC-mismatched lethally irradiated recipients. However, unlike adult IL-2-stimulated adult spleen cells, IL-2-activated NLC lacked CD3+ T cells and failed to induce lethal GVHD. FACS analysis and cell sorting experiments showed that the cells in ANLC which enhanced short-term HSC engraftment belonged to the relatively immature CD3-NK1.1-2B4+ NK cell subset. By contrast, cells belonging to the more mature CD3-NK1.1+2B4+ NK cell subset showed no HSC-enhancing effects. Identification and isolation in humans of similar NK cell enhancers of HSC could lead to a new approach to improving stem cell engraftment in MHC-mismatched recipients without increasing the risk of GVHD.     

Requirement of calcium influx for hydrolytic action of membrane phospholipids by cytosolic phospholipase A2 rather than mitogen-activated protein kinase activation in Fc epsilon RI-stimulated rat peritoneal mast cells

The mechanism by which cytosolic phospholipase A2 (cPLA2) is not responsible for eicosanoid production in rat peritoneal mast cells upon antigen stimulation [Ishimoto et al. (1996) J. Biochem. 120, 616-623] was investigated in the mast cells stimulated by cross-linking of the IgE receptor or with thapsigargin. Stimulation with thapsigargin, but not with antigen, resulted in apparent lysophosphatidylcholine (lysoPC) formation. Antigen stimulation significantly increased the activities of mitogen-activated protein (MAP) kinase and cPLA2. These activities were further potentiated by phorbol ester. The antigen elicited a rapid and transient increase in intracellular Ca2+ concentration, while thapsigargin produced a slow and sustained increase. Furthermore, a combination of antigen and thapsigargin rapidly increased and prolonged the intracellular Ca2+ concentration. Under these conditions, lysoPC was apparently generated, whereas it was not in response to antigen alone. These results suggest that a prolonged increase in the intracellular Ca2+ concentration is required for cPLA2 to associate with membranes, thus leading to hydrolysis of membrane phospholipids by the enzyme.     

Allogenic transplantation of hematopoietic stem cells in the treatment of children with high-risk acute leukemia

BACKGROUND: Most children with acute lymphoblastic leukemia (ALL) and increasing number of children with acute myelogenous leukemia (AML) are currently cured with conventional chemotherapy. Despite of this success there is a subset of patients with high-risk features at diagnosis who are predisposed to a very high risk of relapse. Relapse of AML and early bone marrow relapse of ALL can not be cured by conventional chemotherapy. Allogeneic hematopoietic stem cell transplantation (HSCT) is therapeutic option in these children with very high-risk acute leukemia. METHODS AND RESULTS: Between XI/1989-XII/1996 33 children with acute leukemia (ALL: 22, AML: 11) underwent an allogeneic HSCT from HLA identical related donors (HLA-identical sibling: 30, twin: 1, other HLA-identical relative: 2) at the 2nd Dept. of Pediatrics, University Hospital Motol. Median age of our group was 9 years (1.5-19 y.), boys (n = 23) clearly dominated over the girls (n = 10). The resource of stem cells was bone marrow in 31 children, bone marrow and peripheral blood progenitor cells (PBPC) and PBPC in one child respectively. Myeloablative conditioning regimen varied, consisting of total body irradiation and chemotherapy in 21 children and chemotherapy in 12 children. HSCT was performed in first complete remission of acute leukemia in 9 children (AML: 7, ALL: 2), in second remission in 14 children (AML: 2, ALL: 12), in third remission in 4 children (ALL: 4). Six children underwent HSCT in first partial remission (n = 1) and in second (n = 4) or third (n = 1) chemoresistant relapse. Seven (21%) children died due to post-transplant complications. Nine (28%) children suffered from clinically significant acute graft-versus-host reaction (GVH) and 15% (4/27) children who survived 100 days post-transplant suffered from chronic GVH disease. Relapse of leukemia was diagnosed in 39% (12/31) children. Fourteen (42%) children are alive and well in continuous remission with median follow-up 42 months. CONCLUSIONS: Allogeneic HSCT can cure children with very high-risk acute leukemia in the situations where conventional chemotherapy fails. Relapse of leukemia and GVH reaction are most important causes of post-transplant morbidity and mortality.