Cardiac-derived stem cells

Current scientific dogma holds that cardiomyocyte stem cells do not exist in the adult mammalian heart, and furthermore, that there is little, if any, potential for the regeneration of damaged myocardium. In order to approach this topic, I have begun with a brief overview of advances in stem cell research in other organ systems, such as the bone marrow and the brain. Very recent progress in cardiac stem cell research is then discussed, which indicates that a cardiomyocyte progenitor cell contributes to cardiomyocyte replacement throughout life. This progenitor cell may reside in the heart itself, or derive from a circulating marrow stem cell.     

Targeting cancer stem cells

Recent evidence has demonstrated the existence of a small subset of the tumour mass that is wholly responsible for the sustained growth and propagation of the tumour. This cancer stem cell (CSC) compartment is also likely to be responsible both for disease relapse and the resistance to therapy that often accompanies relapse. The evidence for CSCs in various malignancies is presented. The failure of existing therapeutics to eradicate CSCs suggests that they are relatively resistant to present cancer treatments. This resistance may reflect the preservation of normal stem cell protective mechanisms, such as an increased expression of drug efflux pumps or alterations in apoptotic, cell cycle and DNA repair mechanisms. Targeting these mechanisms, and taking advantage of potential differences in the biology of normal stem cells and CSCs, such as differences in surface phenotype, self renewal/quiescence and stem cell-niche interactions are discussed and preliminary preclinical or clinical data are presented. Finally, the authors give their opinion of the direction in which one must travel to successfully target the CSC and improve treatment outcomes in malignant disease.     

Resident cardiac stem cells

The introduction of stem cells in cardiology provides new tools in understanding the regenerative processes of the normal and pathologic heart and opens new options for the treatment of cardiovascular diseases. The feasibility of adult bone marrow autologous and allogenic cell therapy of ischemic cardiomyopathies has been demonstrated in humans. However, many unresolved questions remain to link experimental with clinical observations. The demonstration that the heart is a self-renewing organ and that its cell turnover is regulated by myocardial progenitor cells offers novel pathogenetic mechanisms underlying cardiac diseases and raises the possibility to regenerate the damaged heart. Indeed, cardiac stem progenitor cells (CSPCs) have recently been isolated from the human heart by several laboratories although differences in methodology and phenotypic profile have been described. The present review points to the potential role of CSPCs in the onset and development of congestive heart failure and its reversal by regenerative approaches aimed at the preservation and expansion of the resident pool of progenitors.     

Human muscle stem cells

Stem cells are unspecialized cells that have been defined in many different ways but they have two important characteristics that distinguish them from other cells in the body. First, they can replenish their numbers for long periods through cell division. Second, after receiving certain chemical signals, they can produce, through asymmetric cell division, a progeny that can differentiate or transform into specialized cells with specific functions, such as heart, nerve or muscle. In recent years, stem cells have received much attention owing to their potential use in cell-based therapies for human neurodegenerative diseases such as Parkinson's disease, stroke and muscular dystrophies. However, many questions need to be resolved before stem cells with myogenic potential are used in clinical standard protocols.     

Targeting cancer stem cells

Recent evidence has demonstrated the existence of a small subset of the tumour mass that is wholly responsible for the sustained growth and propagation of the tumour. This cancer stem cell (CSC) compartment is also likely to be responsible both for disease relapse and the resistance to therapy that often accompanies relapse. The evidence for CSCs in various malignancies is presented. The failure of existing therapeutics to eradicate CSCs suggests that they are relatively resistant to present cancer treatments. This resistance may reflect the preservation of normal stem cell protective mechanisms, such as an increased expression of drug efflux pumps or alterations in apoptotic, cell cycle and DNA repair mechanisms. Targeting these mechanisms, and taking advantage of potential differences in the biology of normal stem cells and CSCs, such as differences in surface phenotype, self renewal/quiescence and stem cell–niche interactions are discussed and preliminary preclinical or clinical data are presented. Finally, the authors give their opinion of the direction in which one must travel to successfully target the CSC and improve treatment outcomes in malignant disease.     

自体脑脊液定向诱导骨髓间充质干细胞分化为神经干细胞

目的 探讨自体脑脊液定向诱导骨髓间充质干细胞分化为神经干细胞的可行性.方法 采用自体脑脊液为诱导剂,体外诱导骨髓源性间充质干细胞.从形态学、免疫组化法、反转录聚合酶链反应(RT-PCR)方法对诱导后细胞进行鉴定.结果 自体脑脊液诱导后的间充质干细胞呈现神经干细胞改变,可分化为神经元、星形胶质细胞和少突胶质细胞,并表现相应的特征结构和生物学特性.结论 白体脑脊液能定向诱导骨髓间充质干细胞向神经样细胞转化.     

Neural stem cells and neurodegeneration

Neurodegenerative diseases, such as Parkinson's disease, are characterized by a continuous loss of specific populations of neurons. Possible regenerative interventions include transplanting developing neural tissue or neural stem cells into the host brain, and inducing proliferation of endogenous stem cells by pharmacological manipulations. Neural stem cells (NSC), with the capacity to self-renew and produce the major cell types of the brain, exist in the developing and adult central nervous system (CNS). These cells can be grown in vitro while retaining the potential to differentiate into nervous tissue. This review focuses on regenerative therapy in neurodegenerative diseases using NSC.     

When stem cells meet immunoregulation

The clinical use of stem cells to prevent tissue injury or reconstruct damaged organs is constrained by different ethical and biological issues. Whereas the use of adult stem cells isolated from differentiated tissues is advantageous from the ethical point of view, the immune response of a host to implants of either embryonic or adult stem cells remains a critical problem. Embryonic stem cells can be rejected by an immunocompetent recipient as well as some types of adult stem cells. There is, however, a population of adult stem cells able to differentiate into the three mesenchymal lineages, osteocytes, chondrocytes, adipocytes that have the additional capacity of modulating the immune response by the activation of disparate mechanisms, among which the generation of antigen-specific CD4+CD25+FoxP3+ regulatory T lymphocytes.This short review will focus on the immunological properties of embryonic and adult stem cells are, with particular emphasis on the immunomodulatory function of mesenchymal stem cells and their interactions with regulatory T lymphocytes.     

Controlled differentiation of stem cells

The extracellular microenvironment plays a significant role in controlling cellular behavior. Identification of appropriate biomaterials that support cellular attachment, proliferation and, most importantly in the case of human embryonic stem cells, lineage-specific differentiation is critical for tissue engineering and cellular therapy. In addition to growth factors and morphogenetic factors known to induce lineage commitment of stem cells, a number of scaffolding materials, including synthetic and naturally-derived biomaterials, have been utilized in tissue engineering approaches to direct differentiation. This review focuses on recent emerging findings and well-characterized differentiation models of human embryonic stem cells. Additionally, we also discuss about various strategies that have been used in stem cell expansion.     

肺干细胞的研究进展

肺干细胞(lung stem cells)是指在特定条件下能分化为功能性肺组织,在维持肺组织更新和肺损伤修复中起着重要作用的细胞。近年来对肺干细胞的研究已取得了很大的进展,该文就肺干细胞的来源、分离方法、应用以及肺癌干细胞等方面的研究进展作如下综述。     

间质干细胞与肿瘤的关系研究进展

间质干细胞(mesenchymal stem cells,MSCs)是来源于中胚层的一类具有高度自我更新能力和多向分化潜能的非造血干细胞,具有很好的组织迁移能力和肿瘤靶向性。MSCs用于抗肿瘤治疗已经开展了广泛的研究,MSCs可以作为细胞载体发挥抗肿瘤作用,同时通过促肿瘤血管生成、免疫抑制、分化为肿瘤相关成纤维细胞等方式促进肿瘤的恶性行为。该文对近年来该领域的研究进展进行简要综述。     

Optimization of adenovirus vectors for transduction in embryonic stem cells and induced pluripotent stem cells

Because embryonic stem (ES) cells and induced pluripotent stem (iPS) cells can differentiate into various types of cells in vitro, they are considered as a valuable model to understand the processes involved in the differentiation into functional cells as well as an unlimited source of cells for therapeutic applications. Efficient gene transduction method is one of the powerful tools for the basic researches and for differentiating ES and iPS cells into lineage-committed cells. Recently, we have developed an adenovirus (Ad) vector for efficient transduction into ES and iPS cells. We showed that Ad vectors containing the cytomegalovirus enhancer/β-actin promoter with β-actin intron (CA) promoter or the elongation factor (EF)-1α promoter were the appropriate for the transduction into ES and iPS cells. We also found that enforced expression of a PPARγ gene or a Runx2 gene into mouse ES and iPS cells by an optimized Ad vector markedly augmented the differentiation of adipocytes or osteoblasts, respectively. Thus, a gene transfer technique using an Ad vector could be an advantage for the regulation of stem cell differentiation and could be applied to regenerative medicine based on ES and iPS cells.