Clinical use of rHuEPO in bone marrow transplantation

Recipients of bone marrow (BMT) or peripheral blood progenitor stem cells (PBSCT) transplant have in the period following transplantation a frequent need for red blood cell transfusions and therefore an increased risk of blood-transmitted infections. The anaemia is caused mainly by myelosuppression after high-dose chemotherapy, but an impaired erythropoietin (EPO) production and an inappropriate EPO response may also contribute. Since recombinant human erythropoietin (rHuEPO) has been established as a treatment for renal anaemia it has been of interest whether treatment may be of benefit in the transplant setting. This paper gives an overview of the studies conducted to date with rHuEPO treatment in patients receiving bone marrow transplants. Current data donot support any transfusional benefits when rHuEPO is used in patients receiving autologous transplants. However, in patients receiving allogeneic transplants several studies clearly indicate a therapeutic role for rHuEPO with patients showing accelerated erythroid engraftment, increased haemoglobin levels, a reduced requirement for red blood cell transfusions, and a shortened time to transfusion independence. Especially patients with immune haemolysis after transplantation seems to benefit from the treatment. In addition, rHuEPO treatment has been used for lateonset anaemia after BMT and to prevent the need for homologous red blood cell transfusions to the BMT donor. To reduce costs, it is important in future studies to identify not only the optimal dose and route of administration of rHuEPO but also the most effective combination with other haematopoietic growth factors and cytokines that are used before and after transplantation.     

Cell transplantation in heart failure management

Heart failure is becoming a major issue for public health in western countries and the effect of currently available therapies is limited. Therefore cell transplantation was developed as an alternative strategy to improve cardiac structure and function. This review describes the multiple cell types and clinical trials considered for use in this indication. Most studies have been developed in models of post-ischemic heart failure. The transplantation of fetal or neonatal cardiomyocytes has proven to be functionally successful, but ethical as well as immunological and technical reasons make their clinical use limited. Recent reports, however, suggested that adult autologous cardiomyocytes could be prepared from stem cells present in various tissues (bone marrow, vessels, adult heart itself, adipose tissue). Alternatively, endothelial progenitors originating from bone marrow or peripheral blood could promote the neoangiogenesis within the scar tissue. Hematopietic stem cells prepared from bone marrow or peripheral blood have been proposed but their differentiation ability seems limited. Finally, the transplantation of skeletal muscle cells (myoblasts) in the infarcted area improved myocardial function, in correlation with the development of skeletal muscle tissue in various animal models. The latter results paved the way for the development of a first phase I clinical trial of myoblast transplantation in patients with severe post-ischemic heart failure. It required the scale-up of human cell production according to good manufacturing procedures, started in june 2000 in Paris and was terminated in november 2001, and was followed by several others. The results were encouraging and prompted the onset of a blinded, multicentric phase II clinical trial for skeletal muscle cells transplantation. Meanwhile, phase I clinical trials also evaluate the safeness and efficacy of various cell types originating from the bone marrow or the peripheral blood. However, potential side effects related to the biological properties of the cells or the delivery procedures are being reported. High quality clinical trials supported by strong pre-clinical data will help to evaluate the role of cell therapy as a potential treatment for heart failure.     

Repopulating potential of hematopoietic precursor cells

Experiments were performed in 1800 cGy whole-body x-irradiated dogs. Mononuclear cells were collected from bone marrow, peripheral blood, and fetal liver. They were cryopreserved in -196 degrees C liquid nitrogen until used for transplantation. The thawed transfusates were adjusted to contain 1.5-1.6 x 10(5) CFU-GM per kg body weight. The blood granulocyte recovery was rapid after transfusion of blood-derived stem cells as compared to the use of bone-marrow-derived stem cells. In both instances, however, normal values were not reached for several weeks. In contrast, the use of fetal-liver-derived stem cells resulted in a very rapid initial granulocyte increase with a return of values to normal (or even overshoot) within 3 weeks after transplantation. A biomathematical granulocyte renewal simulation system is described that permits calculation of the absolute number of pluripotent stem cells in the transfusate. The data after fetal liver stem cell transplantation can be fitted only if an initial stem cell replication rate of 0.95 is assumed (in contrast to 0.65 using bone marrow or blood-derived stem cells).     

Homing and mobilization in the stem cell niche.

All mature blood cells are derived from the haemopoietic stem cell (HSC). In common with all other haemopoietic cells, stem cells are mobile, and it is this property of mobility that has allowed bone marrow transplantation to become a routine clinical option. Successful transplantation requires haemopoietic stem cells to home to the bone marrow, leave the peripheral circulation and become stabilized in regulatory niches in the extravascular space of the bone marrow cavity. This homing and tethering process is reversible - haemopoietic stem cells can be released from their bone marrow tethering through changes in molecular interactions, which are also important in homing following transplantation. The molecular mechanisms regulating this two-way flow of stem cells are beginning to be elucidated, and much recent data has emerged that sheds light on the processes and molecules involved in these complex physiological events. This article reviews current knowledge of the adhesive, homing and proliferative influences acting on HSCs and progenitor cells.     

Cell therapy for type-1 diabetes

A promising approach to treating type-1 diabetes mellitus is cell therapy. Nowadays, in laboratory experiments and clinical studies, allogeneic and xenogeneic cells of Langergance islets, bone marrow cells, hematopoietic stem cells, mesenchymal stem cells, and cord blood stem cells are used for transplantation. Any type of these cells correct the patient status to a certain extent; however, full recovery after cell therapy has not yet been achieved.     

Characteristics of hematopoietic stem cells of umbilical cord blood

Umbilical cord blood collected from the postpartum placenta and cord is a rich source of hematopoietic stem cells (HSCs) and is an alternative to bone marrow transplantation. In this review we wanted to describe the differences (in phenotype, cytokine production, quantity and quality of cells) between stem cells from umbilical cord blood, bone marrow and peripheral blood. HSCs present in cord blood are more primitive than their counterparts in bone marrow or peripheral blood, and have several advantages including high proliferation. With using proper cytokine combination, HSCs can be effectively developed into different cell lines. This process is used in medicine, especially in hematology.     

Isolation and therapeutic potential of human haemopoietic stem cells

The haemopoietic stem cell (HSC) has long been regarded as an archetypal, tissue specific, stem cell, capable of completely regenerating haemopoiesis after myeloablation. It has proved relatively easy to harvest HSC, from bone marrow or peripheral blood. In turn, isolation of these cells has allowed therapeutic stem cell transplantation protocols to be developed, that capitalise on their prodigious self renewal and proliferative capabilities. Ex vivo approaches have been described to isolate, genetically manipulateand expand pluripotent stem cell subsets. These techniques have been crucial to the development of gene therapy, and may allow adults to enjoy the potential advantages of cord blood transplantation. Recently, huge conceptual changes have occurred in stem cell biology. In particular, the dogma that, in adults, stem cells are exclusively tissue restricted has been questioned and there is great excitement surrounding the potential plasticity of these cells, with the profound implications that this has, for developing novel cellular therapies. Mesenchymal stem cells, multipotent adult progenitor cells and embryonic stem cells are potential sources of cells for transplantation purposes. These cells may be directed toproduce HSC, in vitro and in the future may be used for therapeutic, or drug development, purposes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Time course of the differentiation of granulated metrial gland cells in chimeric mice

Granulated metrial gland (GMG) cell differentiation was examined in deciduomata in lethally irradiated mice which had been reconstituted with rat bone marrow. The time at which the bone marrow reconstitution was carried out was varied in relation to the time of initiating the decidual reaction. GMG cells were examined at various times after bone marrow transplantation to determine whether they had the morphology which characterised them as being derived from host or donor stem cells. Differentiation of donor type GMG cells was seen within the first week after transplantation and occurred even when the bone marrow was transplanted two days after initiating the decidual response.     

The clinical potential of stem cells

Stem cells are defined by their capacity for self-renewal and multilineage differentiation, making them uniquely situated to treat a broad spectrum of human diseases. For example, because hematopoietic stem cells can reconstitute the entire blood system, bone marrow transplantation has long been used in the clinic to treat various diseases. Similarly, the transplantation of other tissue-specific stem cells, such as stem cells isolated from epithelial and neural tissues, can treat mouse disease models and human patients in which epithelial and neural cells are damaged. An alternative to tissue-specific stem cell therapy takes advantage of embryonic stem cells, which are capable of differentiating into any tissue type. Furthermore, nuclear transfer, the transfer of a post-mitotic somatic cell nucleus into an enucleated oocyte, creates a limitless source of autologous cells that, when combined with gene therapy, can serve as a powerful therapeutic tool.     

Hematopoietic growth factors in autologous transplantation

Hematopoietic growth factors (HGFs) sustain the survival, proliferation and differentiation of hematopoietic stem cells and some functions of mature blood cells. In man several HGFs have been characterised and cloned so far, and this has allowed investigators to confer the rationale for the clinical application of these molecules in hematology and oncology. In particular G-CSF and GM-CSF are currently utilised to abrogate the hematological toxicity of chemotherapy for standard and dose-intensified therapy, neutropenia following bone marrow and peripheral blood stem cell transplantation. Moreover there has recently been great interest in the ex vivo expansion of hematopoietic stem and progenitor cells for a variety of applications, such as in vitro tumor cell purging or for reducing the volume of blood processed by the leukapheresis. Several combinations of HGFs have been described to sustain the ex vivo survival and proliferation of these cells disclosing new opportunities in the field of stem cells transplants.     

Molecular mechanisms underlying adhesion and migration of hematopoietic stem cells

Hematopoietic stem cell transplantation is the most powerful treatment modality for a large number of hematopoietic malignancies, including leukemia. Successful hematopoietic recovery after transplantation depends on homing of hematopoietic stem cells to the bone marrow and subsequent lodging of those cells in specific niches in the bone marrow. Migration of hematopoietic stem cells to the bone marrow is a highly regulated process that requires correct regulation of the expression and activity of various molecules including chemoattractants, selectins and integrins. This review will discuss recent studies that have extended our understanding of the molecular mechanisms underlying adhesion, migration and bone marrow homing of hematopoietic stem cells.     

Molecular mechanisms underlying adhesion and migration of hematopoietic stem cells

Hematopoietic stem cell transplantation is the most powerful treatment modality for a large number of hematopoietic malignancies, including leukemia. Successful hematopoietic recovery after transplantation depends on homing of hematopoietic stem cells to the bone marrow and subsequent lodging of those cells in specific niches in the bone marrow. Migration of hematopoietic stem cells to the bone marrow is a highly regulated process that requires correct regulation of the expression and activity of various molecules including chemoattractants, selectins and integrins. This review will discuss recent studies that have extended our understanding of the molecular mechanisms underlying adhesion, migration and bone marrow homing of hematopoietic stem cells.     

Adoptive transfer of T-cell precursors enhances T-cell reconstitution after allogeneic hematopoietic stem cell transplantation

Immunoincompetence after allogeneic hematopoietic stem cell transplantation (HSCT) affects in particular the T-cell lineage and is associated with an increased risk for infections, graft failure and malignant relapse. To generate large numbers of T-cell precursors for adoptive therapy, we cultured mouse hematopoietic stem cells (HSCs) in vitro on OP9 mouse stromal cells expressing the Notch-1 ligand Delta-like-1 (OP9-DL1). We infused these cells, together with T-cell-depleted mouse bone marrow or purified HSCs, into lethally irradiated allogeneic recipients and determined their effect on T-cell reconstitution after transplantation. Recipients of OP9-DL1-derived T-cell precursors showed increased thymic cellularity and substantially improved donor T-cell chimerism (versus recipients of bone marrow or HSCs only). OP9-DL1-derived T-cell precursors gave rise to host-tolerant CD4+ and CD8+ populations with normal T-cell antigen receptor repertoires, cytokine secretion and proliferative responses to antigen. Administration of OP9-DL1-derived T-cell precursors increased resistance to infection with Listeria monocytogenes and mediated significant graft-versus-tumor (GVT) activity but not graft-versus-host disease (GVHD). We conclude that the adoptive transfer of OP9-DL1-derived T-cell precursors markedly enhances T-cell reconstitution after transplantation, resulting in GVT activity without GVHD.     

Proliferative and differentiation potentials of skeletogenic bone marrow colony-forming cells

The clonal nature of bone marrow fibroblast colonies derived from clonogenic bone marrow osteogenic cells (CFUf) was proved by the chromosome analysis. During subsequent passages of multi-colony derived bone marrow fibroblast strains there occurs a pronounced increase in the cell number and in the number of osteogenic units (tested by transplantation in diffusion chambers). Single colony-derived strains are capable of forming bone and cartilage simultaneously. It follows that CFUf or part of them are clonogenic cells with high proliferative potentials and are common precursors for bone and cartilage tissue. Thus, CFUf may be regarded as osteogenic stem cells.     

Il-17 mobilizes peripheral blood stem cells with short- and long-term repopulating ability in mice

Autologous and allogeneic bone marrow transplantations have evolved as important cancer therapy modalities. For both indications, peripheral blood has been shown to have distinct advantages over bone marrow as the stem cell source. Cytokine combinations for mobilization have enhanced stem cell yield and accelerated engraftment. However, novel mobilizing agents and strategies are needed to further improve clinical outcomes. Within the donor graft, the dynamic equilibrium between T cells and stem cells critically influences engraftment and transplantation results. IL-17 is a cytokine produced almost exclusively from activated T cells. IL-17 was expressed in vivo with adenovirus technology. Here, proof-of-principle studies demonstrate that IL-17 effectively mobilizes hemopoietic precursor cells (CFU-granulocyte-erythrocyte-macrophage-monocyte, CFU-high proliferative potential) and primitive hemopoietic stem cells (Lin(-/low)c-kit(+)Sca1(+)). Moreover, mouse IL-17 adenovirus-mobilized peripheral blood stem cells rescued lethally irradiated mice. Bone marrow was found to be 45-75% of donor origin at 1 year. In secondary recipients, donor-derived bone marrow cells ranged from 45 to 95%. These data show that IL-17 mobilizes stem cells in mice with short- and long-term reconstituting capacity. Additional comparative studies are needed as well as studies in tumor models to refine distinct potential clinical applications for IL-17-mobilized peripheral blood stem cells.     

The repopulating potential and differentiation capacity of hematopoietic stem cells from the blood and bone marrow of normal mice

Using the hematopoietic colony technique, we have investigated the repopulating potential of bone marrow cells and leukocytes of blood from normal mice and have demonstrated that the frequency of hematopoietic stem cells in bone marrow is 50 to 150 times that of stem cells in the circulating blood. The differentiation capacity of these stem cells has also been examined. Results of comparative studies of the serial sections of hematopoietic colonies formed from marrow and blood leukocytes indicate that the differentiation capacity of stem cells from marrow and blood is similar, and that at least 80% of these cells differentiate along a single cell line. Thus, peripheral blood stem cells can effect a complete hematopoietic graft, establishing in the host, donor red cells, granulocytes, and platelets. The possibility that blood leukocytes may serve as a potential source of stem cells for hematopoietic transplants has been considered. Although blood contains stem cells, their frequency is so low as to make it unlikely that they would become a useful source of precursor cells for transplantation purposes.     

骨髓干细胞移植治疗肝硬化的基础与临床研究现状

肝硬化是一种临床常见的肝病良性终末期表现。目前临床上尚缺乏有效的治疗措施。肝脏移植是最理想的治疗方法,但受供体肝脏来源限制,且费用昂贵。近年来开展的自体骨髓干细胞(BMSCs)移植治疗,为肝硬化的治疗带来了新的希望。BMSCs主要包括造型血干细胞和间充质干细胞,其具有可塑性,体外通过生长因子,体内利用特定微环境均可诱导BMSCs分化为肝前体细胞和成熟肝细胞,并明显改善肝功能。从动物实验到临床研究亦表明,BMSCs具有来源丰富、费用低廉、损伤小、自体移植不栓塞、无排斥反应等优点,为治疗肝病带来了新思路,有望成为生物人工肝的细胞来源。本文就BMSCs移植治疗肝硬化的研究现状,尤其是移植途径以及在肝脏内定居、迁移和分化机制的示踪观察方法和存在的问题作一综述,以期为从事肝病研究的同仁提供参考依据。通过对BMSCs移植从基础研究及临床应用的最新进展的描述,展示BMSCs在肝硬化治疗方面良好的治疗前景。     

Characterization of early B lymphocyte precursors present in long-term bone marrow cultures

Lymphoid precursor cells are present in long-term bone marrow cultures (LTBMC), but their differentiation into mature lymphocytes is blocked. A quantitative assay for B cell precursors in LTBMC, which gives a linear relationship between the number of grafted LTBMC cells and the frequency of B cell colony forming units (CFU-B) in the spleen and bone marrow of immunodeficient CBA/N mice 19 days after reconstitution, is described. Characterization of the B cell precursor indicates that this assay is detecting a very early precursor and not a B lymphocyte or a late pre-B cell. This conclusion is based on the observations that a) pre-B cells transformable by Abelson murine leukemia virus are not present in LTBMC by 3 days postrecharge and CFU-B are absent by 6 days postrecharge; b) late B cell progenitors capable of rapid repopulation of irradiated CBA/N mice are not present in LTBMC, since a lag in the kinetics of B cell reconstitution in animals grafted with LTBMC cells is observed compared with fresh bone marrow cells; c) the B cell precursors in LTBMC have high proliferative potential, since they can stably repopulate recipient mice for at least 8 wk postreconstitution and through two serial passages in irradiated CBA/N recipients; and d) the B cell precursors are large, rapidly sedimenting cells as determined by velocity sedimentation. The serial transplantation experiment further shows that a split is often observed between lymphoid and myeloid reconstituting ability of LTBMC cells. The LTBMC B cell precursor may be a pluripotent stem cell or a lymphoid stem cell, although its differentiative potential remains to be determined.     

Assessing the efficiency of free light chain assay in monitoring patients with multiple myeloma before and after autologous stem cell transplantation along with serum protein electrophoresis and serum protein immunofixation

Monoclonal gammopathies are a group of disorders, referred to as paraproteinaemias, dysproteinaemias or immunoglobulinopathies, associated with monoclonal proliferation of plasma cells. Monoclonal immunoglobulin secreted by these cells is an indicator of clonal proliferation. The aim of this study is to analyze the efficiency of three methods: serum protein electrophoresis (SPE), serum protein immunofixation (IFE) and FLC (free light chain) assay for the diagnosis and monitoring of the tumor burden in multiple myeloma. In this study we have presented the dynamic evolution of 7 patients with intact immunoglobulin multiple myeloma (IIMM) (2 IgG, kapa; 3 IgG, lambda; 1 IgA, kappa; 1 IgA, lambda) and 2 patients with light chain multiple myeloma before and after autologous peripheral blood stem cell transplantation (PBSCT). All 7 patients fulfilled the four criteria for the diagnosis of IIMM: bone marrow plasma cells exceeding 20%, lytic bone lesions, identification and quantification of M protein by scanning densitometry of electrophoresis gels, IFE (immunofixation protein electrophoresis) confirmed and typed the M protein. All patients had been given cytotoxic chemotherapy (VAD or VELCADE) before autologous (PBSCT). In two of the patients with IIMM both SPE and kappa/lambda ratio fell towards normal range after autologous PBSC and both reported a relapse of the disease after 23 months and 19 months respectively. SPE could not normalize after chemotherapy and transplantation in three patients with IIMM, the kappa/lambda ratio being the only marker used to monitor the tumor kill. In one patient the kappa/lambda ratio could not normalize even after PBSCT still indicating the presence of plasma cell disorder at the time when IFE was still negative. 16 months after PBSCT both SPE and FLC indicated a relapse of the disease. Classical SPE failed to demonstrate the presence of M-protein in light chain multiple myeloma, the diagnosis being established by using IFE and the FLC assay. Because IFE is a qualitative method and its interpretation may be sometimes subjective, FLC was the only method used to follow the disease course. The measurement of kappa/lambda ratio proved to be more sensitive than SPE, IFE and the levels of free light chains kappa or lambda individually indicating whether the treatment is effective or not.