Non-myeloablative stem cell transplantation for autoimmune diseases

Treatment of life-threatening autoimmune diseases in animal models with induced or spontaneous autoimmune diseases can be accomplished by a 2-step procedure involving elimination of self-reactive lymphocytes with an immune ablative conditioning regimen followed by infusion of autologous or allogeneic stem cells, respectively. In animal models it was shown that using such a strategy, autoimmunity could be adequately controlled. It is speculated that de-novo development of the T and B cell repertoire from uncommitted progenitor cells in the presence of the autoantigens may be the best recipe for re-induction of self-tolerance, similarly to the normal ontogeny of the immune system during the induction of self tolerance in fetal stage. For both autologous and allogeneic hematopoietic stem cell transplantation, a non-myeloablative stem cell transplantation (NST) regimen may be used for safer lymphoablation rather than myeloablation. In addition, for allogeneic hematopoietic stem cell transplantation engraftment of disease resistant donor stem cells will alter the genetic predisposition towards autoimmune disease susceptibility.     

The immunogenicity of cells derived from induced pluripotent stem cells

With their ability to undergo unlimited self-renewal in culture and to differentiate into all cell types in the body, human embryonic stem ceils （hESCs） hold great potential for the treatment of currently incurable diseases. Two hESC-based cell therapies for spinal cord injury and macular degeneration have been advanced into human clinical trials. Despite this rapid progress, one key challenge of hESC-based cell therapy is the allogeneic immune rejection of hESC-derived cells by recipients. This problem could be mitigated by a recent breakthrough in the technology of induced pluripotent stem cells （iPSCs） by nuclear reprogramming of patient-specific somatic cells with defined factors, which could become a renewable source of autologous ceils for cell therapy. However, recent studies revealing the abnormal epigenetics, genomic stability and immunogenicity of iPSCs have raised safety concerns over iPSC-based therapy. Recent findings related to the immunogenicity of iPSC derivatives will be summarized in this review.     

Haplotype-based banking of human pluripotent stem cells for transplantation: potential and limitations

High expectations surround the area of stem cells therapeutics. However, the cells' source-adult or embryonic-and the cells' origin-patient-derived autologous or healthy donor genetically unrelated-remain subjects of debate. Autologous origins have the advantage of a theoretical absence of immune rejection by the recipient. However, this approach has several limitations with regard to the disease of the recipient and to potential problems with the generation, expansion, and manipulation of autologous induced pluripotent stem cells (iPS cells) preparation. An alternative to using autologous cells is the establishment of a bank of well-characterized adult cells that would be used to generate iPS cells and their derivatives. In the context of transplantation, such cells would come from genetically unrelated donors and the immune system of the recipient would reject the graft without immunosuppressive therapy. To minimize the risk of rejection, human leukocyte antigen (HLA) compatibility is certainly the best option, and the establishment of an HLA-organized bank would mean having a limited number of stem cells that would be sufficient for a large number of recipients. The concept of haplobanking with HLA homozygous cell lines would also limit the number of HLA mismatches, but such an approach will not necessarily be less immunogenic in terms of selection criteria, because of the limited number of HLA-compatible loci and the level of HLA typing resolution.     

Anti-HLA antibodies in regenerative medicine stem cell therapy

Research on stem cell therapies for regenerative medicine is progressing rapidly. Although the use of autologous stem cells is a tempting choice, there are several instances in which they are either defective or not available in due time. Allogenic stem cells derived from healthy donors presents a promising alternative. Whether autologous or allogenic, recent advances have proven that stem cells are not as immune privileged as they were thought. Therefore understanding the interactions of these cells with the recipient immune system is paramount to their clinical application. Transplantation of stem cells induces humoral as well as cellular immune response. This review focuses on the humoral response elicited by stem cells upon their administration and consequences on the survival and maintenance of the graft. Current transplantation identifies pre- and post-transplantation anti-HLA antibodies as immune rejection and cell signaling effectors. These two mechanisms are likely to operate similarly in the context of SC therapeutics. Ultimately this knowledge will help to propose novel strategies to mitigate the allogenic barriers. Immunogenetics selection of the donor cell and immunomonitoring are key factors to allow the implementation of regenerative stem cell in the clinics.     

Regulatory T cells in autologous stem cell transplantation for autoimmune disease

Since a decade autologous stem cell transplantation (ASCT) is successfully performed to treat patients with severe autoimmune disease. However, the mechanism of action of this intervention remains largely unknown. Scarce data from animal studies and human clinical trials indicate that, besides extensive immune ablation, restoration of regulatory immune networks is of critical importance. This review focuses on the role of naturally occurring and induced regulatory T cells in controlling immune reconstitution and restoration of immune tolerance and in preventing relapses of disease following ASCT.     

干细胞若干定义的相关探讨

背景：近10年来干细胞研究所取得的巨大进展,不仅影响和促进了生物学及其相关基础科学,而且还在医学、药物开发、农业等许多领域得到广泛的应用,目前已成为研究的热点问题。 目的：在干细胞的定义上还存在一些需要探讨的问题,明确定义将有利于干细胞研究的快速发展。 方法：回顾干细胞的发展和概念提出,特别是通过中英文权威定义的比较,提出作者的看法。 结果与结论：干细胞的定义上还存在一些问题值得探讨,特别是一些中英文表述不同影响了理解。例如,“多能干细胞”对应译成两个单词：Pluripotent Stem Cell和Multipotent Stem Cell,然而Pluripotent和Multipotent两个单词的英文意义不同。为了学术交流和沟通,作者提出将Pluripotent Stem Cell称为“万能干细胞”,而保留Multipotent Stem Cell为“多能干细胞”的定义。以上结论供广大同仁探讨,以利于抛砖引玉。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Advantages of mesenchymal stem cell over the other stem cells

A stem cell is a particular group of cells that has the extraordinary potential to convert within the body into particular cell types. They are used to regenerate tissues and cells in the body that have been damaged or destroyed by the disease. Stem cells come in three different varieties: adult stem cells, embryonic stem cells and induced pluripotent stem cells (iPSCs). Embryonic stem cells have a high chance of immune rejection and also have ethical dilemmas and iPSCs have genetic instability. Adult stem cells are difficult to analyze and extract for research since they are frequently insufficient in native tissues. However, mesenchymal stem cells (MSC) one of the categories of adult stem cells are stromal cells with a variety of potentials that can differentiate into a wide range of cell types. MSCs can be transplanted into a variety of people without worrying about rejection because they have demonstrated the ability to prevent an adverse reaction from the immune system. These transplants have powerful anti-inflammatory and immunosuppressive effects and greatly enhance the body's inherent healing capacity. While MSCs do not offer treatment for illnesses, the idea behind them is to enable the body to recover sufficiently for a protracted reduction in symptoms. In many cases, this is sufficient to significantly enhance the patient’s well-being. Inspite of several advantages some potential long-term concerns connected to MSC therapy are maldifferentiation, immunosuppression and cancerous tumor growth. In this review, we will compare the mesenchymal stem cells with other stem cells with respect to the source of origin, their properties and therapeutic applications, and discuss the MSC’s disadvantages.     

自体外周血造血干细胞移植后序贯CIK细胞治疗急性髓系白血病

背景：细胞因子诱导的杀伤细胞作为一种有效的过继免疫治疗方法,成为治疗急性髓系白血病的一种新的手段,目前关于急性髓系白血病自体移植后序贯细胞因子诱导的杀伤细胞治疗的报道尚少,值得进一步研究。 目的：观察急性髓系白血病M2患者自体外周血造血干细胞移植后序贯细胞因子诱导的杀伤细胞治疗的临床疗效和不良反应。 方法：入选45例低、中危急性髓系白血病M2患者,其中19例在自体外周血造血干细胞移植后序贯了细胞因子诱导的杀伤细胞治疗,另26例未序贯细胞因子诱导的杀伤细胞治疗,比较两组患者的复发率、无病生存率、总生存率,观察细胞因子诱导的杀伤细胞治疗的安全性。 结果与结论：①序贯细胞因子诱导的杀伤细胞治疗组的复发率低于未序贯细胞因子诱导的杀伤细胞治疗组(21.05%,38.46%,P < 0.05);序贯细胞因子诱导的杀伤细胞治疗组患者的2年无病生存率和2年总生存率均高于未序贯细胞因子诱导的杀伤细胞治疗组,差异均有显著性意义(P < 0.05)。②19例接受细胞因子诱导的杀伤细胞治疗的患者均顺利完成治疗方案,治疗过程中除4例出现寒战、发热外,无其他不良反应。结果显示低、中危急性髓系白血病M2患者自体外周血造血干细胞移植后序贯细胞因子诱导的杀伤细胞治疗可降低原发病的复发率,提高患者的无病生存率及总生存率,且无明显不良反应,是一种安全、有效、可行的治疗方法。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Cancer stem cells in glioblastoma

Tissues with defined cellular hierarchies in development and homeostasis give rise to tumors with cellular hierarchies, suggesting that tumors recapitulate specific tissues and mimic their origins. Glioblastoma (GBM) is the most prevalent and malignant primary brain tumor and contains self-renewing, tumorigenic cancer stem cells (CSCs) that contribute to tumor initiation and therapeutic resistance. As normal stem and progenitor cells participate in tissue development and repair, these developmental programs re-emerge in CSCs to support the development and progressive growth of tumors. Elucidation of the molecular mechanisms that govern CSCs has informed the development of novel targeted therapeutics for GBM and other brain cancers. CSCs are not self-autonomous units; rather, they function within an ecological system, both actively remodeling the microenvironment and receiving critical maintenance cues from their niches. To fulfill the future goal of developing novel therapies to collapse CSC dynamics, drawing parallels to other normal and pathological states that are highly interactive with their microenvironments and that use developmental signaling pathways will be beneficial.     

Multipotent stem and progenitor cells of the olfactory epithelium

In recent decades, a wide spectrum of fetal and embryonic stem and progenitor cells were used for cell therapy of diseases of the central nervous system, but the olfactory glial ensheathing cells exhibited certain advantages due to their biological properties and capacity to stimulate regeneratory processes in spinal injury. The therapeutic effect of a heterogeneous complex of olfactory epithelial cells is more pronounced; apart from glial ensheathing cells, this complex includes fibroblasts, Schwann cells, stem and progenitor cells of this structure. The use of minimally invasive methods for isolation of human olfactory epithelial tissue is important for clinical practice, because they provide cells for autologous transplantation and rule out graft rejection immune reaction and the risk of transmission viral infection and transfer of genetic defects, which can be associated with allotransplantation. __________ Translated from Kletochnye Tekhnologii v Biologii i Medicine, No. 4, pp. 185–193, December, 2006     

Contribution of human hematopoietic stem cells to liver repair

Immune-deficient mouse models of liver damage allow examination of human stem cell migration to sites of damage and subsequent contribution to repair and survival. In our studies, in the absence of a selective advantage, transplanted human stem cells from adult sources did not robustly become hepatocytes, although some level of fusion or hepatic differentiation was documented. However, injected stem cells did home to the injured liver tissue and release paracrine factors that hastened endogenous repair and enhanced survival. There were significantly higher levels of survival in mice with a toxic liver insult that had been transplanted with human stem cells but not in those transplanted with committed progenitors. Transplantation of autologous adult stem cells without conditioning is a relatively safe therapy. Adult stem cells are known to secrete bioactive factors that suppress the local immune system, inhibit fibrosis (scar formation) and apoptosis, enhance angiogenesis, and stimulate recruitment, retention, mitosis, and differentiation of tissue-residing stem cells. These paracrine effects are distinct from the direct differentiation of stem cells to repair tissue. In patients at high risk while waiting for a liver transplant, autologous stem cell therapy could be considered, as it could delay the decline in liver function.     

内源性骨髓间充质干细胞与骨折微环境中的相关趋化因子

背景：研究表明,骨髓间充质干细胞定向迁移依赖于损伤局部表达趋化因子与细胞表面相应受体的相互作用。然而,哪些趋化因子在介导骨髓间充质干细胞向骨折部位定向迁移过程中起关键作用,目前尚不清楚。 目的：对内源性骨髓间充质干细胞进行示踪,观察其在骨修复中的作用;检测并筛选出骨折微环境中表达量高且与骨髓间充质干细胞趋化规律相关的因子。 方法：建立C57BL/6小鼠荧光/普通骨髓嵌合体,利用嵌合体动物模型制造胫骨骨折模型,在不同时相点检测骨折部位组织绿色荧光蛋白阳性细胞占所有细胞的比例、来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的比例,判断来源于骨髓的骨髓间充质干细胞在骨折修复中的作用;利用免疫组化等方法检测骨折部位不同时相点趋化因子的蛋白表达水平。 结果与结论：骨折局部绿色荧光蛋白阳性细胞占所有细胞比例在术后1,5,14 d分别为(3.011±0.911)%,(9.031±0.145)%,(12.064±0.145)%;来源于骨髓间充质干细胞的成骨细胞占全部成骨细胞的50%以上;骨折后各时相点微环境中基质细胞衍生因子1、集落刺激因子、肝细胞生长因子、单核细胞趋化蛋白1、间质金属蛋白酶9有不同程度的表达,粒细胞集落刺激因子无明显表达。基质细胞衍生因子1的表达量相对最高。经相关分析认为：基质细胞衍生因子1在骨折微环境中的表达与骨髓间充质干细胞趋化规律具有相关关系。结果表明骨髓内的骨髓间充质干细胞参与骨折修复并在其中起到了重要作用;基质细胞衍生因子1促进骨髓间充质干细胞的定向趋化并参与骨组织的修复。     

自体干细胞移植治疗严重下肢缺血

背景：严重下肢缺血是周围血管疾病中难于治疗的疾病,自体干细胞移植方法的运用可以为该病的治疗带来一定的希望。 目的：总结自体干细胞移植治疗严重下肢缺血的发展近况,探讨其机制及存在的问题。 方法：以“干细胞,移植,严重下肢缺血”,“stem cell,transplant,critical limb ischemia”为检索词,检索时间1990年1月至2013年3月,检索数据库：万方数据库、中国知网和Pubmed数据库,纳入与自体干细胞移植治疗严重下肢缺血疾病方面的相关研究,排除与研究无关和重复文献,保留47篇文献进行综述。 结果和结论：对于严重下肢缺血的自体干细胞移植治疗,干细胞类型、数量、分离方式,是否有细胞因子的刺激都可能影响治疗效果,自体干细胞移植治疗严重下肢缺血是一全新治疗手段,疗效显著,但是自体干细胞如何长期维持治疗效果其机制尚不清楚,尚需进一步研究和探讨。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

自体骨髓干细胞治疗肝硬化基础研究与临床应用现状

背景：活体肝移植仍面临很多问题：如供体的匮乏、移植后的免疫排异反应及其高额的费用等,因此使其在临床上的开展受到限制。 目的：说明自体骨髓干细胞移植可以分化成熟肝细胞而替代受损的肝脏组织发挥功能,从而改善患者症状,提高患者生活质量。 方法：利用计算机在PubMed、CNKI、万方数据库和维普数据库中检索2000-01/2010-12关于自体骨髓干细胞移植相关文章,在标题和摘要中用“骨髓干细胞;自体骨髓干细胞移植;肝硬化”或“Bone marrow stem cell,autologous bone marrow stem cell,hepatic cirrhosis”为检索词进行检索。选择与骨髓干细胞移植相关的文章内容,同一领域文献选择近期发表或发表在权威杂志文章。初检得到235篇文献,根据纳入标准选择20篇文章进行综述。 结果与结论：通过对自体骨髓干细胞移植从基础研究及临床研究方面的最新进展的了解,说明自体骨髓干细胞移植在对肝硬化的治疗方面前景广阔。     

Colonic and colorectal cancer stem cells: progress in the search for putative biomarkers

The maintenance of healthy colonic crypts is dependent on the integrity of the adult epithelial stem cells located within them. Perturbations in stem cell dynamics are generally believed to represent the first step towards colorectal tumorigenesis. Experimental manipulation of intestinal stem cells has greatly increased our understanding of them, but further progress has been slowed due to the absence of a reliable stem cell biomarker. In this review we discuss the candidate colonic stem cell biomarkers which have been proposed. Furthermore, we investigate the putative biomarkers for so-called colorectal cancer stem cells, a highly aggressive subpopulation of cells considered to drive tumour development.     

Biology of human bone marrow stem cells

Abstract. The bone marrow is constituted of two separate and distinct stem cells. The hematopoietic stem cells (HSC) are responsible for the production and maintenance of all the mature blood cells. The mesenchymal stem cells constituted the bone marrow stroma. In this report we review our current understanding on both stem cell populations. We also discuss the recent unexpected degree of differentiation plasticity that have been reported recently and the impacts these new discoveries may have in stem cell therapy.     

Engraftable neural crest stem cells derived from cynomolgus monkey embryonic stem cells

Neural crest stem cells (NCSCs), a population of multipotent cells that migrate extensively and give rise to diverse derivatives, including peripheral and enteric neurons and glia, craniofacial cartilage and bone, melanocytes and smooth muscle, have great potential for regenerative medicine. Non-human primates provide optimal models for the development of stem cell therapies. Here, we describe the first derivation of NCSCs from cynomolgus monkey embryonic stem cells (CmESCs) at the neural rosette stage. CmESC-derived neurospheres replated on polyornithine/laminin-coated dishes migrated onto the substrate and showed characteristic expression of NCSC markers, including Sox10, AP2α, Slug, Nestin, p75, and HNK1. CmNCSCs were capable of propagating in an undifferentiated state in vitro as adherent or suspension cultures, and could be subsequently induced to differentiate towards peripheral nervous system lineages (peripheral sympathetic neurons, sensory neurons, and Schwann cells) and mesenchymal lineages (osteoblasts, adipocytes, chondrocytes, and smooth muscle cells). CmNCSCs transplanted into developing chick embryos or fetal brains of cynomolgus macaques survived, migrated, and differentiated into progeny consistent with a neural crest identity. Our studies demonstrate that CmNCSCs offer a new tool for investigating neural crest development and neural crest-associated human disease and suggest that this non-human primate model may facilitate tissue engineering and regenerative medicine efforts.     

Pluripotent stem cells

The isolation of human embryonic stem cells (ESC) in 1998 has created the hope that stem cells will one day be used to regenerate tissues and organs, even though it is obvious that a number of hurdles will need to be overcome for such therapies to become reality. The cloning of “Dolly” in 1997, more than 40 years after the first frogs were cloned, combined with the very fast progress made in our understanding of the molecular processes that govern the pluripotency of ESC has lead to the ability of scientists to recreate a pluripotent state in fibroblasts and other cells from mouse, rat and man, named induced pluripotent stem cells (iPSC). This feat makes it theoretically possible to create patient specific pluripotent stem cells whose differentiated progeny could be used in an autologous manner obviating the need for immunesuppression that would be needed to use allogeneic ESC-derived differentiated cells. In addition, the ability to generate custom made pluripotent stem cells will no doubt lead to the development of protein or small molecule drugs that can induce differentiation not only of iPSC or ESC to mature tissue cells, but also endogenous tissue stem cells. Moreover, it allows scientists to create models of human diseases and may aid the pharmaceutical industry in testing more rigorously toxicity of drugs for human differentiated cells. Thus, there is little doubt that progress in stem cell biology will change many aspects of medicine as we know it in the next one to two decades.