干细胞诱导分化生殖细胞的研究进展

干细胞是一类具有自我更新和分化潜能的细胞,包括胚胎干细胞和成体干细胞。胚胎干细胞是从囊胚内细胞团中获得的具有全能性的细胞,具备了分化成机体所有细胞类型的潜能,包括生殖细胞。近年来人类胚胎干细胞的研究取得了突破性进展,能在体外培养成精子细胞及成熟的卵母细胞,但存在免疫排斥、致瘤性和伦理学等问题,使其应用在临床治疗方面受限。成体干细胞是一种多能干细胞,理论上成体干细胞在一定条件下也可分化为生殖细胞。成体干细胞则可克服这些缺点,应用前景日益被看好。若将成体干细胞向生殖细胞的分化应用于临床,使分化成的生殖细胞能发育成具有生命的子代,那将为不育提供一条新的治疗途径。综述了胚胎干细胞及成体干细胞向生殖细胞分化方面的研究进展。     

成体细胞诱导产生多能干细胞的研究进展

近年来,利用特定的转录因子将体细胞诱导为诱导多能干（iPS）细胞的研究获得了突破性进展。iPS细胞技术是干细胞研究领域的一次革命,不仅解决了胚胎干细胞来源引起的伦理问题,而且避免了细胞移植引起的免疫排斥作用。现就成体细胞诱导产生iPS细胞相关的几种转录因子以及诱导方法、如何提高诱导产生iPS细胞的效率以及iPS细胞临床应用前景等问题进行综述。     

诱导性多能干细胞在锰中毒治疗中的应用展望

通过特殊的技术将体细胞重编程为具有自我更新能力和多向分化潜能的细胞,这种细胞叫做诱导多能干细胞(induced pluripotent stem cell,iPS cell)。它在形态学以及表观遗传学与胚胎干细胞极为相似。目前,已经成为干细胞和再生医学领域研究的热点。长期职业性锰暴露的人群会出现震颤、肌强直和运动迟缓等类似帕金森病的中毒症状。本文拟从iPS细胞的研究概述、诱导步骤及筛选方法三个方面简介iPS细胞的研究进展并对其在锰中毒治疗中的应用作以展望。 更多还原     

人皮肤成纤维细胞来源诱导性多潜能干细胞的建立和鉴定

目的建立和鉴定人皮肤成纤维细胞（HSF）来源的诱导性多潜能干细胞（iPS）。方法利用逆转录病毒将Sox2、Klf4、Oct4、c-Myc基因导入原代HSF细胞,将其编程为iPS细胞。检测细胞内源、外源基因表达量,鉴定外源基因是否插入iPS细胞,分析细胞核型,细胞碱性磷酸酶染色和免疫荧光染色,体内分化畸胎瘤,体外分化拟胚体实验,对建立的iPS细胞进行鉴定。结果（1）iPS细胞形态类似于胚胎干细胞（ES）。（2）iPS细胞内源多能基因（Nanog、Oct4、Rexl、Sox2）表达量增高,外源编程基因（Sox2、Klf4、Oct4、c-Myc）表达量降低。（3）琼脂糖凝胶电泳实验证实外源基因插入iPS细胞核内。（4）iPS细胞核型正常,碱性磷酸酶活性增高,表达ES细胞特异性蛋白。（5）iPS细胞在体内能分化为畸胎瘤,在体外能分化为拟胚体。结论新建立的iPS细胞类似于ES细胞具有多向分化潜能。     

干细胞向生殖细胞分化的研究进展

胚胎干细胞（ESC）是一种多能干细胞,具有向生殖细胞分化的能力,由于具有致瘤性和伦理问题,限制了ESC向临床应用发展的前景。成体干细胞（ASC）也是一类多能干细胞,理论上也能分化为生殖细胞,但诱导分化过程往往受到阻滞。诱导性多能干细胞（iPS）是一种具有多能性的重编程体细胞,一定程度上可替代ESC用于基础和临床研究。目前,全球不孕不育的发生率呈逐年递增的趋势,充分认识干细胞向生殖细胞分化的机制是解决该难题的重要理论前提。就各种干细胞向生殖细胞分化的研究进展作一综述。     

脐带间充质细胞来源诱导性多潜能干细胞的建立和鉴定

目的建立和鉴定脐带间充质细胞（UMC）来源的诱导性多潜能干细胞（iPS）。方法以逆转录病毒作为Sox2、KIf4、Oct4、c—Myc基因转移载体,将UMC细胞编程为iPS细胞。应用RT-PCR检测细胞基因表达量,鉴定外源编程基因是否整合到iPS细胞核内,分析细胞核型,对细胞进行碱性磷酸酶染色和免疫荧光染色,体内分化畸胎瘤和体外分化拟胚体实验,对建立的iPS细胞进行鉴定。结果（1）iPS细胞形态学上类似于胚胎干细胞（ES）。（2）iPS与ES细胞内源多能基因（Nanog、Oct-4、Rexl、Sox-2）表达谱相类似,外源编程基因（Sox-2、KIf4、Oct-4、c—Myc）表达发生沉默。（3）外源编程基因已被插入到iPS细胞核内。（4）iPS细胞核型正常,碱性磷酸酶活性增高,表达Es细胞特异性膜蛋白（SSEA3、SSEA4）,质蛋白（TRA-1-60、TRA-1—81）,核蛋白（Nanog）。（5）iPS细胞在体内能分化为畸胎瘤,在体外能分化为拟胚体。结论iPS细胞类似于Es细胞具有多向分化潜能。     

人类胚胎干细胞研究中伦理学问题

人类胚胎干细胞研究对人类多种疾病的治疗有着广泛的应用前景，已成为21世纪生物医学研究热点。同样重要的是，人们还必须面对有关人类胚胎干细胞研究中的伦理学问题：人类胚胎的利益与成人(病人)利益之间的冲突问题。     

羊水多潜能干细胞的研究现状及前景展望

由于强大的自我更新能力和多向分化的潜能,多潜能干细胞被广泛应用于再生医学的研究.胚胎干细胞的研究因伦理道德问题而受到限制.羊水多潜能干细胞的发现为多潜能干细胞的研究开辟了新的领域,引起了广大学者的关注.该文就羊水多潜能干细胞的生物学性状、分化潜能、临床应用前景等予以综述.     

042 小鼠胚胎干细胞在遗传和发育毒理学中的应用

小鼠胚胎干细胞包括胚胎干细胞、胚胎生殖细胞和胚胎癌细胞3种类型,是唯一可以同时研究致突变物对未分化胚胎细胞和分化体细胞致突变性的细胞株,其对致突变物的敏感性因检测终点的不同而有所不同.在胚胎毒性检测方面,由于胚胎干细胞可以同时检测化学物对细胞增殖和分化的影响,从而大大提高了体外替代实验的预测符合率,有望成为化学物致畸试验的体外替代实验模型.同时,转基因技术的广泛应用和人源胚胎干细胞的建系将更有助于提高化学物胚胎毒性和致畸性体外预测符合率,但同时也存在较大的伦理学争议.     

小鼠胚胎干细胞在遗传和发育毒理学中的应用

小鼠胚胎干细胞包括胚胎干细胞、胚胎生殖细胞和胚胎癌细胞3种类型，是唯一可以同时研究致突变物对未分化胚胎细胞和分化体细胞致突变性的细胞株，其对致突变物的敏感性因检测终点的不同而有所不同。在胚胎毒性检测方面，由于胚胎干细胞可以同时检测化学物对细胞增殖和分化的影响，从而大大提高了体外替代实验的预测符合率，有望成为化学物致畸试验的体外替代实验模型。同时，转基因技术的广泛应用和人源胚胎干细胞的建系将更有助于提高化学物胚胎毒性和致畸性体外预测符合率，但同时也存在较大的伦理学争议。     

Stem cells: therapeutic applications and experimental techniques

Stem cells are being used more frequently for research and experimental therapy, but as yet the clinical applications of stem cells are limited. Pluripotent stem cells, with embryonic stem cells as the most well know example, can differentiate into each cell type; in contrast, tissue specific stem cells can only form one or more cell types within one type of tissue. It has been possible for some time to reprogram different types of somatic cells into pluripotent stem cells. Such stem cells are termed induced pluripotent stem cells (iPS cells). iPS cells can also be created from cells of patients with genetic conditions. Research into mechanisms of pathology and new medicines can be carried out with these against a specific genetic background. Clinical application of such iPS cells is not to be expected in the short term. Facilities are being established in different Dutch academic centres to create iPS cells for scientific research. Conflict of interest: none declared.     

Blurring nature at its boundaries. Vague phenomena in current stem cell debate

This paper illuminates the explanatory role of vagueness und species membership against the background of scientific developments in recent stem cell research. With the help of the Neo-Aristotelian concept of “life form naturalism” ontologically vague entities such as stem cells, all above induced pluripotent stem cells (iPS), could be described as necessary constituents for the correct sorting and naming of natural processes and its bearers. Furthermore this specific assessment allows drawing some important ontological and ethical consequences.     

Effects of ionizing radiation on proliferation and differentiation of mouse induced pluripotent stem cells

The present study aimed to estimate the clonogenic and differentiation potential of induced pluripotent stem (iPS) cells exposed to ionizing radiation. Compared with mouse hematopoietic stem/progenitor cells, iPS cells were less sensitive to radiation. To examine the effect of ionizing radiation on the early differentiation pathway of iPS cells, we assessed embryoid body (EB) formation. Although EB formation was observed at all radiation doses, EB diameter decreased in a radiation dose-dependent manner. At the same time, we analyzed the expression of genes specific to differentiation in the initial iPS cells and cells of EB. The expression of the endoderm marker Afp increased remarkably in cells of EB derived from non-irradiated iPS cells; however, in irradiated cells, this expression significantly decreased in a radiation dose-dependent manner. Further, the expressions of the pluripotent stem cell markers Nanog and Oct-4 and the early mesoderm marker Brachyury significantly decreased. The results of the present study suggest that radiosensitivity with regard to gene expression differs at various stages in the early differentiation pathways of iPS cells that lead to the formation of the 3 germ layers; the sensitivity is the highest in the genes expressed during the differentiation pathways of iPS cells, leading to the formation of the endoderm.     

Stem cell sources for cardiac regeneration

Cell-based cardiac repair has the ambitious aim to replace the malfunctioning cardiac muscle developed after myocardial infarction, with new contractile cardiomyocytes and vessels. Different stem cell populations have been intensively studied in the last decade as a potential source of new cardiomyocytes to ameliorate the injured myocardium, compensate for the loss of ventricular mass and contractility and eventually restore cardiac function. An array of cell types has been explored in this respect, including skeletal muscle, bone marrow derived stem cells, embryonic stem cells (ESC) and more recently cardiac progenitor cells. The best-studied cell types are mouse and human ESC cells, which have undisputedly been demonstrated to differentiate into cardiomyocyte and vascular lineages and have been of great help to understand the differentiation process of pluripotent cells. However, due to their immunogenicity, risk of tumor development and the ethical challenge arising from their embryonic origin, they do not provide a suitable cell source for a regenerative therapy approach. A better option, overcoming ethical and allogenicity problems, seems to be provided by bone marrow derived cells and by the recently identified cardiac precursors. This report will overview current knowledge on these different cell types and their application in cardiac regeneration and address issues like implementation of delivery methods, including tissue engineering approaches that need to be developed alongside.     

间充质干细胞分泌因子调节氧化应激的作用

衰老和疾病发生发展大多伴随氧化应激水平升高，包括多囊卵巢综合征、卵巢储备减少和卵巢早衰等生殖内分泌疾病。干细胞治疗已应用于多种疾病或其临床研究，而间充质干细胞（MSC）相对于胚胎干细胞和诱导多能干细胞具有明显的优势，如应用于子宫内膜粘连、多囊卵巢综合征和卵巢早衰临床治疗的研究。MSC分泌的众多细胞因子对组织细胞内氧化应激具有调节作用。研究发现，白细胞介素6（IL-6）和脑源性神经营养因子（BDNF）能激活核因子E2相关因子2（Nrf2）通路降低氧化应激水平。综述MSC分泌因子的抗氧化应激作用，阐述其可能的细胞内作用机制，为探讨MSC临床应用提供新思路。     

干细胞治疗薄型子宫内膜的研究进展

在辅助生殖技术中,子宫内膜厚度可以反映内膜功能状态,薄型子宫内膜是指子宫内膜厚度不足以获得胚胎着床及临床妊娠。虽然临床对薄型子宫内膜治疗的方式较多,但总体治疗效果欠佳。干细胞因具有多向分化和自我更新的潜能而展现出广阔的发展前景,包括胚胎干细胞、成体干细胞和诱导多能干细胞,随着对干细胞研究的深入,目前有研究诱导干细胞向子宫内膜细胞定向分化并增生,以促进子宫内膜生长,进而用于治疗薄型子宫内膜。现主要就骨髓间质干细胞（BMSCs）、子宫内膜干细胞（EDSCs）、人胚胎干细胞（hESCs）及人脐带华通胶间充质干细胞（WJ-MSCs）在薄型子宫内膜治疗的研究进展以及这4种细胞用于临床治疗的优缺点进行综述。     

Humane embryonale Stammzellen im Kontext internationaler Forschungsaktivitäten

Research involving pluripotent human embryonic stem cells (hESCs) is a rapidly growing field of science. Since hESCs originate from early human embryos, alternative methods for producing pluripotent cells have been developed. This article introduces some of those strategies and, in addition, covers international efforts to establish consistent international standards for cultivation, characterization and preservation of hESCs. Furthermore, global trends to form networks in the field of stem cell research as well as endeavors to harmonize ethical standards for hESC research are presented. Finally, potential applications of hESCs in the field of pharmacology/toxicology are discussed as well as recent results of animal studies using hESCs.     

Ethical boundary-work in the embryonic stem cell laboratory

Most accounts of the ethics of stem cell research are de- contextualised reviews of the ethical and legal literature. In this chapter we present a socially embedded account of some of the ethical implications of stem cell research, from the perspectives of scientists directly involved in this area. Based on an ethnography of two leading embryonic stem cell laboratories in the UK, our data form part of the findings from a larger project mapping the scientific, medical, social and ethical dimensions of innovative stem cell treatment, focusing on the areas of liver cell and pancreatic islet cell transplantation. We explore three key issues: what individual scientists themselves view as ethical sources of human embryos and stem cells; their perceptions of human embryos and stem cells; and how scientists perceive regulatory frameworks in stem cell research. We argue that these dimensions of laboratory practice are all examples of 'ethical boundary-work', which is becoming an integral part of the routine practice and performance of biomedical science. Our work adds to the relatively few sociological studies that explore ethics in clinical settings and to an even smaller body of work that explores scientists' views on the ethical issues relating to their research.