体细胞重编程逆转为干细胞的研究进展

目前细胞和发育生物学上的研究成果为生物医学研究提供了广泛的前景.将完全分化的细胞重编程,不经过胚胎逆转为多能干细胞状态,这点燃了再生医学应用的新希望,这一成果从法律、道德、伦理等不同方面被人们所接受.通过体细胞克隆胚胎获得干细胞所面临的破坏胚胎的伦理限制,促使研究者去寻求将分化细胞重编程逆转为干细胞的新方法.主要论述了体细胞重编程的原理、过程及不经过胚胎逆转为多能干细胞的方法.     

揭秘成体干细胞

干细胞研究给人类带来很多福音已是不争的事实,但作为干细胞研究主要部分的胚胎干细胞研究在取得系列成果的同时也带来了一系列的伦理争议(见本刊上期)。而时于成体干细胞的研究在一定程度上回避了伦理问题。本文系统介绍了成体干细胞研究的基础知识、研究现状及发展前景。细读此文,相信你一定会有所收获。     

人脐带间充质干细胞研究进展及应用前景

人脐带问充质干细胞（hUCMSC）是来源于发育早期中胚层和外胚层、存在于脐带沃顿胶和血管周围组织中的一类具有自我更新、增殖和多向分化潜能的干细胞。当前主要通过分离、扩增传代培养,然后超低温保存的方法提取保存hUCMSC。与其他来源的干细胞相比,hUCMSC具有来源广泛、可塑性强、对供者无不利影响、无伦理争论限制等优势,并且具有很强的向多组织分化的潜能,因此hUCMSC成为在组织工程、造血干细胞移植及基因治疗等研究领域具有巨大潜力的种子细胞,在临床应用方面有十分广阔的前景。     

当代基因伦理研究问题探析

基因伦理研究是生命伦理学的一个重要分支。围绕着基因中心文化现象、基因检测技术、生物样本库建设以及基因增强带来的伦理问题,既关注＂我们应该做什么＂的实质伦理学研究,也进行＂我们应该怎样做＂的程序伦理学研究,探讨中国文化背景和社会转型下基因伦理研究的重要工作,为下一步的基因伦理研究提供启示。     

干细胞研究的伦理问题

人类胚胎干细胞研究的伦理问题来自两个方面。首先,胚胎干细胞是从人类胚胎中获得的,这样就冲破了对人胚胎研究的禁区。其次,胚胎干细胞的研究将不可避免地涉及克隆人的技术,因而使人们不得不切实地面对克隆人的问题。     

科学家首次利用人体皮肤细胞培育出类胚胎干细胞

美国和日本的科学家通过改造人体皮肤细胞，培育出一种外观和作用与胚胎干细胞（ES）非常接近的干细胞。这项技术使得在不使用胚胎或卵母细胞的前提下生产用于疾病研究或治疗的干细胞成为可能，从而避开一直困扰学术界的伦理争论．大大推动了与干细胞有关的疾病疗法研究。     

军事医学科学院干细胞与再生医学研究回顾与展望

干细胞具有高度自我更新、增殖和多向分化潜能,因而成为再生医学的基础.作为中国干细胞研究与应用的＂先驱＂单位和优势单位之一,我院早期开展造血干细胞生物学性能、造血调控机制、造血干/祖细胞扩增和定向诱导分化的研究,取得了一系列重要成果.相继开展的造血干细胞移植等系列研究和应用也取得了突出的成绩.近年来,我院又系统开展了胚胎干细胞自我更新与干性维持机制、干细胞增殖分化调控、干细胞建系与建库技术造血发育调控与造血干细胞移植新策略、成体干细胞治疗、肿瘤干细胞筛选与鉴定、干细胞为种子细胞的三维组织构建、干细胞再生相关药物等多个领域的研究,并取得突出进展进一步我们将瞄准干细胞与再生医学的重大科学问题和关键技术,建立高水平的研究和应用基地,形成我院干细胞与再生医学研究开发的关键技术体系,研发系列具有自主知识产权的关键技术和产品,并培养优秀的科研团队,进入世界先进行列.     

干细胞研究步入充满活力的新时代

“国际干细胞组织伦理学研讨会”和“国际干细胞组织第八届年会”日前在北京举行,27个国家和研究机构的代表出席该会议,就国际人类干细胞领域的政策制定、管理调控、干细胞研究涉及的伦理问题及障碍、干细胞最新研究进展和未来发展趋势等问题进行探讨。     

脂肪干细胞的研究进展

成体干细胞包括多能诱导干细胞、胚胎干细胞、脐带血干细胞、脂肪干细胞等,其中脂肪干细胞因其取材方便,无伦理限制,且能诱导成多胚层细胞而成为最有应用前景的成体干细胞之一。脂肪干细胞可以诱导分化为脂肪细胞、骨细胞、软骨细胞、肌细胞和神经元,在特定的条件下,可以构建皮肤,骨和软骨组织工程,是多种组织工程的理想种子细胞,有非常重要的研究和应用价值。本文综述了ADSC的分离培养、诱导分化,并着重对脂肪干细胞在组织工程临床应用方面的最新发展进行了阐述,以期为深入研究脂肪干细胞提供理论基础。     

胚胎干细胞技术的研究进展

干细胞可以分为成体干细胞和胚胎干细胞两类,是当前生物医学领域的一个热点。由于干细胞在医学领域有巨大应用前景,世界各国都对此给予了相当的重视;投入大量资金支持本国的科学家从事干细胞的科学研究。目前,干细胞的研究还处于试验室阶段,很多技术难题还没有解决,尤其是胚胎干细胞的不定向分化问题,以及一些伦理方面的争议。宗教界人士和社会论理学方面的人士对于干细胞的研究还有异议。集中论述了胚胎干细胞的研究进展和医学功用。     

Aspects on properties, use and ethical considerations of embryonic stem cells – A short review

Mammalian embryonic stem cells have the potential to differentiate into all cell types of an adult individual. The culturing of human embryonic stem cells renders possible studies that were previously only available in animal models. Embryonic stem cells constitute a particularly attractive tool for studies of self-renewal, commitment, differentiation, maturation and cell-cell interaction. There is currently considerable hope that studies of embryonic stem cells will lead to new therapies; either by themselves, through cell replacement strategies, or by generating results assisting other fields of research to reach clinical results. There are, however, considerable challenges to be met before embryonic stem cells can be used in large-scale clinical trials.Stem cell research is an area that has given rise to much debate internationally, within science, law and politics as well as within philosophy and ethics. The ethical attitudes expressed in the public debate over stem cell research notably divide over three important distinctions: (1) Reproductive versus therapeutic cloning; (2) Using already existing embryos versus producing new embryos for research purposes; (3) Production of embryos from eggs and sperm versus through somatic-cell nuclear transfer. The potential medical benefits that may result from embryonic stem cell research arguably support a continued development in this area. However, some opponents argue that this research offends the (relative or absolute) moral status of an unborn human. Furthermore, the research would probably prove to be a both time-consuming and very expensive method for treating disease. Thus, the questions arise whom the new technique wouldbenefit and at what cost, if ever developed. This revised version was published online in July 2006 with corrections to the Cover Date.     

Developments in stem cell research and therapeutic cloning: Islamic ethical positions, a review

Stem cell research is very promising. The use of human embryos has been confronted with objections based on ethical and religious positions. The recent production of reprogrammed adult (induced pluripotent) cells does not - in the opinion of scientists - reduce the need to continue human embryonic stem cell research. So the debate continues. Islam always encouraged scientific research, particularly research directed toward finding cures for human disease. Based on the expectation of potential benefits, Islamic teachings permit and support human embryonic stem cell research. The majority of Muslim scholars also support therapeutic cloning. This permissibility is conditional on the use of supernumerary early pre-embryos which are obtained during infertility treatment in vitro fertilization (IVF) clinics. The early pre-embryos are considered in Islamic jurisprudence as worthy of respect but do not have the full sanctity offered to the embryo after implantation in the uterus and especially after ensoulment. In this paper the Islamic positions regarding human embryonic stem cell research and therapeutic cloning are reviewed in some detail, whereas positions in other religious traditions are mentioned only briefly. The status of human embryonic stem cell research and therapeutic cloning in different countries, including the USA and especially in Muslim countries, is discussed.     

Muscle-derived stem cells: implications for effective myoblast transfer therapy

Stem cells have been proposed as a wonder solution for tissue repair in many situations and have attracted much attention in the media for both their therapeutic potential and ethical implications. In addition to the excitement generated by embryonic stem cells, research has now identified a number of stem cells within adult tissues which pose much more realistic targets for therapeutic interventions. Myoblast transfer therapy (MTT) has long been viewed as a potential therapy for the debilitating muscle-wasting disorder Duchenne Muscular Dystrophy. This technique relies on the transplantation of committed muscle precursor cells directly into the muscle fibres but has had little success in clinical trials. The recent discovery of a population of cells within adult muscle with stem cell-like characteristics has interesting implications for the future of such putative cell transplantation therapies. This review focuses on the characterization and application of these potential muscle-derived stem cells (MDSC) to MTT.     

Fetal stem cells from extra-embryonic tissues: do not discard

Stem cells hold promise to treat diseases currently unapproachable, including Parkinson's disease, liver disease and diabetes. Seminal research has demonstrated the ability of embryonic and adult stem cells to differentiate into clinically useful cell types in vitro and in vivo. More recently, the potential of fetal stem cells derived from extra-embryonic tissues has been investigated. Fetal stem cells are particularly appealing for clinical applications. The cells are readily isolated from tissues normally discarded at birth, avoiding ethical concerns that plague the isolation embryonic stem cells. Extra-embryonic tissues are large, potentially increasing the number of stem cells that can be extracted. Lastly, the generation and sequestration of cells that form extra-embryonic tissues occurs early in development and may endow resident stem cell populations with enhanced potency. In this review we summarize recent work examining the plasticity and clinical potential of fetal stem cells isolated from extra-embryonic tissues.     

The generation of GLP-grade human embryonic stem cell banks from four clinical-grade cell lines for preclinical research

The Singapore Stem Cell Bank has generated human embryonic stem cell banks from clinical-grade cell lines ESI-017, ESI-035, ESI-049, and ESI-053. All banks were prepared and characterized according to principles of Good Laboratory Practice for quality assurance. Importantly, each cell line has clearly documented and approved ethical provenance and meets recognized standards for performance and safety. The banks are intended to facilitate the translation of stem cell research to clinical medicine by enabling early phase research and development with high-quality, low-cost cells that are also available as clinical-grade stocks.     

干细胞生物工程研究展望

 由于最近两年干细胞研究技术的突破 ,一门崭新的学科“干细胞生物工程”已经形成 .人类胚胎干细胞在体外的成功培养以及一种组织的干细胞 (成体干细胞 )向另一种组织细胞横向分化的发现 ,为利用“干细胞生物工程”技术治疗疾病奠定了基础 .本综述着重介绍干细胞研究领域的一些新概念和新技术以及干细胞分化的基因调控 .对干细胞生物工程的临床应用前景作了概括性讨论     

International stem cell registries

Rapid advances in stem cell research have led to the derivation of hundreds of human embryonic stem (hES) cell lines in centers throughout the world, as well as the development of new technologies for producing pluripotent stem cells. These cell lines have unique characteristics and were derived using a variety of ethical guidelines. Stem cell registries have been developed in order to collect, organize, and disseminate cell line-specific information. In this review, we describe the current state of the field by providing an overview of the unique qualities and mandates of the three major stem cell registries: the European hES Cell Registry, the Registry of hES Cell Line Provenance developed by the International Society for Stem Cell Research, and the International Stem Cell Registry of hES and induced pluripotent stem cell lines established at the University of Massachusetts Medical School. While each registry has its own unique mandate and features, there is some overlap in the goals and information provided. This review discusses the challenges and prospects for an integrated approach in which all three registries effectively collaborate to minimize duplication and facilitate information exchange within the stem cell community.     

UNCERTAIN TRANSLATION,UNCERTAIN BENEFIT AND UNCERTAIN RISK: ETHICAL CHALLENGES FACING FIRST‐IN‐HUMAN TRIALS OF INDUCED PLURIPOTENT STEM (IPS) CELLS

The discovery of induced pluripotent stem (iPS) cells in 2006 was heralded as a major breakthrough in stem cell research. Since then, progress in iPS cell technology has paved the way towards clinical application, particularly cell replacement therapy, which has refueled debate on the ethics of stem cell research. However, much of the discourse has focused on questions of moral status and potentiality, overlooking the ethical issues which are introduced by the clinical testing of iPS cell replacement therapy. First‐in‐human trials, in particular, raise a number of ethical concerns including informed consent, subject recruitment and harm minimisation as well as the inherent uncertainty and risks which are involved in testing medical procedures on humans for the first time. These issues, while a feature of any human research, become more complex in the case of iPS cell therapy, given the seriousness of the potential risks, the unreliability of available animal models, the vulnerability of the target patient group, and the high stakes of such an intensely public area of science. Our paper will present a detailed case study of iPS cell replacement therapy for Parkinson's disease to highlight these broader ethical and epistemological concerns. If we accept that iPS cell technology is fraught with challenges which go far beyond merely refuting the potentiality of the stem cell line, we conclude that iPS cell research should not replace, but proceed alongside embryonic and adult somatic stem cell research to promote cross‐fertilisation of knowledge and better clinical outcomes.     

Stem cell niche: Dynamic neighbor of stem cells

Stem cell niche is a specialized and dynamic microenvironment around the stem cells which plays a critical role in maintaining the stemness properties of stem cells. Over the years, advancement in the research activity has revealed the various important aspects of stem cell niche including cell-cell interaction, cell-extracellular matrix interaction, a large number of soluble signaling factors and various biochemical and biophysical cues (such as oxygen tension, flow, and shear and pore size). Stem cells have the potential to be a powerful tool in regenerative medicine due to their self-renewal property and immense differentiation potential. Recent progresses in in vitro culture conditions of embryonic stem cells, adult stem cells and induced pluripotent stem cells have enabled the researchers to investigate and understand the role of the microenvironment in stem cell properties. The engineered artificial stem cell niche has led to a better execution of stem cells in regenerative medicine. Here we elucidate the key components of stem cell niche and their role in niche engineering and stem cell therapeutics.     

Stem cell politics, ethics and medical progress

Tremendous controversy has surrounded efforts to undertake research on totipotent human stem cells. To date public policy in the United States has attempted to skirt the ethical and social questions raised by this research. Annas et al. argue that research using human embryos as a source of totipotent stem cells can secure broad public support if there is an open and public discussion about the ethical justification for undertaking such research and the assurance of adequate federal regulation and oversight.