自体骨髓干细胞移植治疗肝硬化研究进展

目的干细胞是一类具有自我更新和分化潜能的细胞,骨髓干细胞(BMSCs)直接来源于成人的骨髓,具有极强的可塑性,自体BMSCs在活体肝脏内可分化为有功能的肝细胞和胆管细胞。BMSCs经分离纯化后移植到肝脏,可以在肝脏内逐渐分化为有功能的肝细胞,逐渐改善肝脏功能,为中、晚期肝硬化治疗提供新途径。本文综述了BMSCs与肝脏的关系、BMSCs在肝脏内分化的条件和机制、BMSCs移植治疗肝硬化的临床前及临床研究,以期为从事肝病研究的临床医生提供肝硬化治疗的新方法和参考依据。     

骨髓基质干细胞诱导分化为神经细胞的研究进展

骨髓基质干细胞具有取材简单、增殖速度快、培养过程中始终保持多向分化的潜能等特点,已经成为干细胞研究领域的热点,是最好的组织工程种子细胞之一,还可以诱导分化为神经细胞。本文对骨髓基质干细胞诱导分化为神经细胞的研究进展作一综述。     

胎盘间充质干细胞向神经细胞诱导的实验研究

目的间充质干细胞(MSCs)具有自我更新和多向分化能力的特点，尽管其主要来源骨髓间充质干细胞(BMSCs)已被认为是治疗多种疾病的良好细胞来源。但在严重感染或随着年龄的增长骨髓细胞数及增殖、分化能力均明显下降等情况下，就无法顺利获得足量可用于治疗的BMSC，有必要寻找MSC的新来源。方法消化胎盘组织、贴壁培养获得基质细胞；用流式细胞仪检测其细胞表面标志；比较叔丁对甲氧酚(butylated hydroxyanisole，BHA)、复方丹参注射液、β-巯基乙醇(BME)等对培养的基质细胞向神经细胞分化的作用；采用免疫细胞化学的方法对分化的细胞进行鉴定。结果胎盘组织中分离出的基质细胞与骨髓间充质干细胞有相似形态和细胞表面标志，并可诱导表达神经元和星型胶质细胞标志神经元特异性烯醇化酶(neuron specific enolasen，NSE)、神经微丝(neurofilament，NF)和胶质纤维酸性蛋白(glial fibrilament acidic protein，GFAP)。结论胎盘组织中存在能分化为神经元样细胞的间充质干细胞。胎盘间充质干细胞可能是一种可为临床治疗提供丰富新来源的间充质干细胞。     

干细胞的可塑性与皮肤再生医学

干细胞具有稳定的存活、增殖和保持多向分化潜能的特性,在皮肤再生医学和未来组织工程皮肤领域具有广泛的研发潜力。在成年动物皮肤、神经系统、骨髓造血系统和肝脏等多种组织中存在着增殖和分化能力强的干细胞。本文主要就干细胞的分类、干细胞的可塑性、成熟细胞向干细胞逆分化、干细胞基因治疗与皮肤再生医学,以及干细胞临床应用的安全性等内容系统地进行了概述。     

成人干细胞在心血管疾病中的应用价值

干细胞是一类具有高度自我更新和很强分化潜能的细胞 ,包括胚胎干细胞和成人干细胞。干细胞分裂后 ,一个保持干细胞的全部特性 ,维持其干细胞的大小和质量 ,另一个分化为各系的祖细胞 ,即干细胞的不对称分裂。而祖细胞是指一类由干细胞分化而来的细胞 ,已失去自我更新能力的过渡性增生性细胞群体 ,在一定条件下能分化成单一的细胞 ,也称为定向干细胞。1　成人干细胞的来源及分化特性1 1　来源 :成人干细胞分为造血干细胞和间充质干细胞。造血干细胞主要存在于骨髓、婴儿脐血 ,少量由骨髓释放到外周血液中 ,而间充质干细胞主要存在于骨髓。1 …     

骨髓间充质干细胞在组织修复中的作用

间充质干细胞(MSC)是干细胞家族的重要成员,来源于发育早期的中胚层和外胚层。MSC最初在骨髓中发现,随后还发现存在于人体发生、发育过程的多种组织中,由于骨髓是其主要来源,因此统称为骨髓间充质干细胞。因BMSCs具有多向分化潜能、造血支持和促进干细胞植入、免疫调控和自我复制等特点而日益受到人们的关注。己经成为治疗多种组织损伤性疾病的理想种子细胞。     

自体骨髓干细胞移植治疗下肢缺血性疾病的研究现状

骨髓干细胞是成体干细胞的一种,具有自我更新和分化潜能,在特定条件下可分化为不同的组织细胞或器官,自体骨髓干细胞移植通过增强移植部位组织细胞更新或替换缺损组织来治疗多系统疾病,前景乐观。现就目前自体骨髓干细胞移植治疗下肢缺血性疾病的研究状况进行综述。     

碱性成纤维细胞生长因子对骨髓间质干细胞的作用

骨髓中的细胞包括造血细胞和非造血细胞两大类，其中骨髓基质非造血细胞中含有间质干细胞（Mesenchymal Stem Cells，MSCs）。骨髓间质干细胞具有自我增殖和多向分化的特性，在不同诱导条件下可分化成多种类型的结缔组织，如骨、软骨、骨骼肌、肌腱、韧带、真皮、脂肪和骨髓基质，也可分化成神经系统的神经元和神经胶质细胞等。近年来，骨髓间质干细胞被认为是组织工程的一种理想种子细胞，在骨、软骨、肌腱组织工程，中枢神经系统疾病及颅脑损伤修复、心肌重建、创面修复、协助重建造血、细胞和基因治疗等方面都已显示了良好的应用前景。国内外学者对它向各种组织细胞的诱导分化方面，作了大量的基础研究与临床研究。     

碱性成纤维细胞生长因子对骨髓间质干细胞的作用

骨髓中的细胞包括造血细胞和非造血细胞两大类,其中骨髓基质非造血细胞中含有间质干细胞(MesenchymalStemCells,MSCs)。骨髓间质干细胞具有自我增殖和多向分化的特性[1],在不同诱导条件下可分化成多种类型的结缔组织,如骨、软骨、骨骼肌、肌腱、韧带、真皮、脂肪和骨髓基质,也可分化成神经系统的神经元和神经胶质细胞等。近年来,骨髓间质干细胞被认为是组织工程的一种理想种子细胞,在骨、软骨、肌腱组织工程,中枢神经系统疾病及颅脑损伤修复、心肌重建、创面修复、协助重建造血、细胞和基因治疗等方面都已显示了良好的应用前景。国内外学…     

骨髓间充质干细胞生物学特性及其多向分化潜能的理论基础和机制

骨髓分为造血和基质两大系统，前者包括造血干细胞和各阶段血细胞；后者指骨髓腔内为造血系统提供结构和功能支持的结缔组织。因此，正常骨髓至少存在两种干细胞：骨髓造血干细胞（HSCs）和骨髓基质干细胞（MSCs）。后者以往被统称为骨髓基质细胞（BMSCs）。骨髓基质干细胞是近年才被确认的成体干细胞。长期以来，BMSCs一直被认为是骨髓中的造血结构性和功能性支持细胞，为造血干细胞的定居、自我更新和分化提供场所。后发现这些细胞易于在塑料瓶／皿表面贴壁生长，     

Bone marrow transplantation: a new strategy for intractable diseases

Bone marrow transplantation is becoming a powerful strategy for the treatment of hematologic disorders (leukemia, aplastic anemia, etc.), congenital immunodeficiencies, metabolic disorders and also autoimmune diseases. Using various animal models for autoimmune diseases, we have previously found that allogeneic (not autologous) bone marrow transplantation can be used to treat autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, immune thrombocytic purpura, insulin-dependent diabetes mellitus, chronic glomerulonephritis and certain types of non-insulin-dependent diabetes mellitus. In contrast, we have found that the transplantation of T-cell-depleted bone marrow cells or partially purified hemopoietic stem cells from autoimmune-prone mice to normal mice leads to the induction of autoimmune diseases in the recipients. These findings have recently been confirmed even in humans; autoimmune diseases such as rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis and Crohn's disease were resolved after allogeneic bone marrow transplantation. However, there have recently been reports on the rapid recurrence or persistence of autoimmune diseases after autologous bone marrow transplantation. Conversely, the adoptive transfer of autoimmune diseases such as myasthenia gravis, insulin-dependent diabetes mellitus and Graves' disease by allogeneic bone marrow transplantation from donors to recipients has been reported. Owing to these findings, we have proposed that autoimmune diseases are "stem cell disorders." We have thus succeeded in treating autoimmune diseases in various autoimmune-prone mice, except MRL/lpr mice, by conventional bone marrow transplantation. The MRL/lpr mouse itself is radiosensitive (<8.5 Gy), while the abnormal hemopoietic stem cells of the MRL/lpr mouse are radioresistant (>8.5 Gy); conventional bone marrow transplantation (8.5 Gy plus bone marrow transplantation) has a transient effect on autoimmune diseases, which recur three months after the bone marrow transplantation. However, bone marrow transplantation plus bone grafts (to recruit donor stromal cells) completely prevents the recurrence of autoimmune diseases in MRL/lpr mice. Donor-derived stromal cells (including mesenchymal stem cells) thus seem to play a crucial role in successful allogeneic bone marrow transplantation, since there is a major histocompatibility complex restriction between hemopoietic stem cells and stromal cells. We have, however, found that the combination of bone marrow transplantation plus bone grafts has no effect on the treatment of autoimmune diseases in MRL/lpr mice, since MRL/lpr mice become more radiosensitive after the onset of lupus nephritis due to the development of uremic enterocolitis. To reduce the cytotoxic effect of radiation on the intestine, we carried out fractionated irradiation and devised a new strategy. We injected allogeneic whole bone marrow cells (including a small number [<3%] of T cells, hemopoietic stem cells and stromal cells) from donors directly into the intra-bone marrow of recipients so that donor-derived hemopoietic cells including stromal cells could effectively accumulate in the bone marrow. All the MRL/lpr mice survived more than one year (>60 weeks after birth) without the recurrence of autoimmune diseases, and immunological functions were completely restored even when the radiation dose was reduced to 5 Gy x 2. These findings suggest that intra-bone marrow injection-bone marrow transplantation can be used to treat intractable autoimmune diseases under reduced radiation doses without using any immunosuppressants.Intra-bone marrow injection-bone marrow transplantation seems to be the best strategy for allogeneic bone marrow transplantation: 1) no graft-versus-host disease develops even if T cells are not depleted from the bone marrow; 2) no graft failure occurs even if the dose of radiation as the conditioning for bone marrow transplantation is reduced to 5 Gy x 2; 3) hemopoietic recovery is rapid; and 4) T-cell functions are completely restored even in donor-recipient combinations across the major histocompatibility complex barriers. Using cynomolgus monkeys, we have recently established a new method (the "perfusion method") for collecting bone marrow cells from the long bones (femur, humerus, etc.) without peripheral blood contamination. This method has various advantages: 1) no graft-versus-host disease develops even in cynomolgus monkeys, since the percentage of T cells in the bone marrow cells collected is less than 3%; 2) a large number of bone marrow cells can be collected quickly and safely; and 3) the bone marrow cells collected contain stromal cells including mesenchymal stem cells. We therefore believe that this method (intra-bone marrow injection-bone marrow transplantation in conjunction with the perfusion method) will become a powerful new strategy for not only allogeneic bone marrow transplantation but also organ transplantation in conjunction with bone marrow transplantation. Furthermore, this method could become a valuable strategy in regeneration therapy for injured organs and tissues (myocardial infarction, cerebral infarction, Alzheimer's disease, etc.), since it can efficiently reconstitute the recipient with both donor-derived hemopoietic stem cells and mesenchymal stem cells.     

Impact of bone marrow on respiratory disease

The bone marrow is not only a site of haematopoiesis but also serves as an important reservoir for mature granulocytes and stem cells, including haematopoietic stem cells, mesenchymal stem cells and fibrocytes. In respiratory diseases, such as asthma and idiopathic pulmonary fibrosis these cells are mobilised from the bone marrow in response to blood-borne mediators and subsequently recruited to the lungs. Although the granulocytes contribute to the inflammatory reaction, stem cells may promote tissue repair or remodelling. Understanding the factors and molecular mechanisms that regulate the mobilisation of granulocytes and stem cells from the bone marrow may lead to the identification of novel therapeutic targets for the treatment of a wide range of respiratory disorders.     

Regeneration of cartilage and bone by defined subsets of mesenchymal stromal cells--potential and pitfalls

Mesenchymal stromal cells, also referred to as mesenchymal stem cells, can be obtained from various tissues. Today the main source for isolation of mesenchymal stromal cells in mammals is the bone marrow. Mesenchymal stromal cells play an important role in tissue formation and organogenesis during embryonic development. Moreover, they provide the cellular and humoral basis for many processes of tissue regeneration and wound healing in infancy, adolescence and adulthood as well. There is increasing evidence that mesenchymal stromal cells from bone marrow and other sources including term placenta or adipose tissue are not a homogenous cell population. Only a restricted number of appropriate stem cells markers have been explored so far. But routine preparations of mesenchymal stromal cells contain phenotypically and functionally distinct subsets of stromal cells. Knowledge on the phenotypical characteristics and the functional consequences of such subsets will not only extend our understanding of stem cell biology, but might allow to develop improved regimen for regenerative medicine and wound healing and novel protocols for tissue engineering as well. In this review we will discuss novel strategies for regenerative medicine by specific selection or separation of subsets of mesenchymal stromal cells in the context of osteogenesis and bone regeneration. Mesenchymal stromal cells, which express the specific cell adhesion molecule CD146, also known as MCAM or MUC18, are prone for bone repair. Other cell surface proteins may allow the selection of chondrogenic, myogenic, adipogenic or other pre-determined subsets of mesenchymal stromal cells for improved regenerative applications as well.     

New Insights into the Pathogenesis and Treatment of Idiopathic Pulmonary Fibrosis: A Potential Role for Stem Cells in the Lung Parenchyma and Implications for Therapy

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and often fatal form of interstitial lung disease. It is characterized by injury with loss of lung epithelial cells and abnormal tissue repair, resulting in replacement of normal functional tissue, abnormal accumulation of fibroblasts and myofibroblasts, deposition of extracellular matrix, and distortion of lung architecture which results in respiratory failure. Despite improvements in the diagnostic approach to IPF and active research in recent years, the molecular mechanisms of the disease remain poorly understood. This highly lethal lung disorder continues to pose major clinical challenges since an effective therapeutic regimen has yet to be identified and developed. For example, a treatment modality has been based on the assumption that IPF is a chronic inflammatory disease, yet most available anti-inflammatory drugs are not effective in treating it. Hence researchers are now focusing on understanding alternative underlying mechanisms involved in the pathogenesis of IPF in the hope of discovering potentially new pharmaceutical targets. This paper will focus on lung tissue repair, regeneration, remodeling, and cell types that may be important to consider in therapeutic interventions and includes a more detailed discussion of the potential targets of current therapeutic attack in pulmonary fibrosis. The discovery that adult bone marrow stem cells can contribute to the formation of differentiated cell types in other tissues, especially after injury, implies that they have the potential to participate in tissue remodeling, and perhaps regeneration. The current promise of the use of adult stem cells for tissue regeneration, and the belief that once irreversibly damaged tissue could be restored to a normal functional capacity using stem cell-based therapy, suggests a novel approach for treatment of diverse chronic diseases. However this optimism is tempered by current evidence that the pathogenesis of pulmonary fibrosis may involve the recruitment of bone marrow-derived fibroblasts, which are the key contributors to the pathogenesis of this chronic progressive disorder. Nevertheless, stem cell-related therapies are widely viewed as promising treatment options for patients suffering from various types of pulmonary diseases. Gender mismatched bone marrow or lung transplant recipients serve as natural populations in which to study the role of bone marrow-derived stem cells in recovery from pulmonary diseases. Understanding the mechanism of recruitment of stem cells to sites of injury, and their involvement in tissue repair, regeneration, and remodeling may offer a novel therapeutic target for developing more effective treatments against this fatal disorder. This article reviews the new concepts in the pathogenesis, current and future treatment options of pulmonary fibrosis, and the recent advances regarding the roles of stem cells in lung tissue repair, regeneration, and remodeling.     

A new paradigm for stem cell therapy: Substance-P as a stem cell-stimulating agent

Bone marrow is a reservoir for hematopoietic stem cells, endothelial precursor cells, and bone marrow stromal cells (also generally called mesenchymal stem cells), whose positive role in tissue repair is highly anticipated. In this report, we introduce a novel function of substance-P (SP), an 11-amino-acid peptide, as an injury-inducible messenger to mobilize bone marrow stem cells to the blood and finally to engage in tissue repair. This new drug may substitute for ex vivo cell culture of therapeutic cells by stimulating cell proliferation in the bone marrow in vivo and mobilizing those therapeutic cells to the patient’s own blood stream. Again, the additional role of SP in mitigating inflammation-mediated tissue damage can further rationalize the clinical development of SPpeptide as a stem cell stimulant.     

Bone marrow-derived cells: the influence of aging and cellular senescence

During the course of an entire lifespan, tissue repair and regeneration is made possible by the presence of adult stem cells. Stem cell expansion, maintenance, and differentiation must be tightly controlled to assure longevity. Hematopoietic stem cells (HSC) are greatly solicited given the daily high blood cell turnover. Moreover, several bone marrow-derived cells including HSC, mesenchymal stromal cells (MSC), and endothelial progenitor cells (EPC) also significantly contribute to peripheral tissue repair and regeneration, including tumor formation. Therefore, factors influencing bone marrow-derived cell proliferation and functions are likely to have a broad impact. Aging has been identified as one of these factors. One hypothesis is that aging directly affects stem cells as a consequence of exhaustive proliferation. Alternatively, it is also possible that aging indirectly affects stem cells by acting on their microenvironment. Cellular senescence is believed to have evolved as a tumor suppressor mechanism capable of arresting growth to reduce risk of malignancy. In opposition to apoptosis, senescent cells accumulate in tissues. Recent evidence suggests their accumulation contributes to the phenotype of aging. Senescence can be activated by both telomere-dependent and telomere-independent pathways. Genetic alteration, genome-wide DNA damage, and oxidative stress are inducers of senescence and have recently been identified as occurring in bone marrow-derived cells. Below is a review of the link between cellular senescence, aging, and bone marrow-derived cells, and the possible consequences aging may have on bone marrow trans plantation procedures and emerging marrow-derived cell-based therapies.     

Heart regeneration: what cells to use and how?

Coronary artery disease (CAD) is the leading cause of death in modern societies. Recent achievements in the treatment of CAD including statins, ACE inhibitors, beta blockers, and interventional procedure improved the outcome of patients with CAD, but this conventional approach failed to control cardiovascular mortality. Nowadays, cells (stem cells) and their potential role in managing patients with heart disease is a field of intensive research. Various types of cells have been used for transplantation targeting heart regeneration, including bone marrow cells (BMCs), cardiac stem cells (CSCs), endothelial progenitor cells (EPCs), skeletal myoblasts (SMs), adipose stroma tissue cells (ATSCs), mesenchymal cells (MCs), and embryonic stem cells (ESCs). Several routes have been used to deliver these cells to human myocardium or to the coronary circulation such as, intracoronary injection, intravenous infusion, direct injection into the ventricular wall, or transepicardial/transendocardial infusions. Although the results of the recent clinical trials in this area are rather conflicting, these therapeutic approaches seem to be promising for the treatment of ischemic heart disease.     

Morphological and cytofluorimetric analysis of adult mesenchymal stem cells expanded ex vivo from periodontal ligament

Many adult tissues contain a population of stem cells that have the ability of regeneration after trauma, disease or aging. Recently, there has been great interest in mesenchymal stem cells and their roles in maintaining the physiological structure of tissues, and their studies have been considered very important and intriguing, after having shown that this cell population can be expanded ex vivo to regenerate tissues not only of the mesenchymal lineage, such as intervertebral disc cartilage, bone, tooth-associated tissue, cardiomyocytes, but also to differentiate into cells derived from other embryonic layers, including neurons. Currently, different efforts have been focused on the identification of odontogenic progenitors from oral tissues. In this study we isolated and characterized a population of homogeneous human mesenchymal stem cells proliferating in culture with an attached well-spread morphology derived from periodontal ligament, a tissue of ectomesenchymal origin, with the ability to form a specialized joint between alveolar bone and tooth. The adherent cells were harvested and expanded ex vivo under specific conditions and analysed by FACScan flow cytometer and morphological analysis was carried out by light, scanning and transmission electron microscopy. Our results displayed highly evident cells with a fibroblast-like morphology and a secretory apparatus, probably indicating that the enhanced function of the secretory apparatus of the mesenchymal stem cells may be associated with the secretion of molecules that are required to survive and proliferate. Moreover, the presence in periodontal ligament of CD90, CD29, CD44,CD166, CD 105, CD13 positive cells, antigens that are also identified as stromal precursors of the bone marrow, indicate that the periodontal ligament may turn out to be a new efficient source of the cells with intrinsic capacity to self-renewal, high ability to proliferate and differentiate, that can be utilized for a new approach to regenerative medicine and tissue engineering.     

骨髓来源成骨细胞体外成骨表达的研究

目的探索在体外诱导兔骨髓基质干细胞(bone marrow stem cells,BMSCs)向成骨细胞分化及成骨表达的特性。方法抽取兔骨髓,通过离心法获取单个核细胞,在体外经条件培养基培养21d,通过倒置显微镜及激光共聚焦显微镜观察成骨细胞的形态学特点;应用MTT法测定成骨细胞活性;并检测成骨细胞分泌碱性磷酸酶活性及形成矿化结节情况。结果体外BMSCs可在成骨条件培养液下诱导培养后可向成骨细胞分化,经倒置显微镜和激光共聚焦显微镜观察证实,诱导后BMSCs由长梭形转变为短胖形的成骨细胞,MTT检测成骨细胞活性良好,分泌碱性磷酸酶并形成矿化结节。结论骨髓基质干细胞在体外可定向诱导为成骨细胞,并具有成骨细胞功能,有希望成为理想的种子细胞应用于临床。