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。     

Differential Impact of Science Policy on Subfields of Human Embryonic Stem Cell Research

In this research, we examine how restrictive policy influenced performance in human embryonic stem cell research (hESC) between 1998 and 2008. In previous research, researchers argued whether restrictive policy decreased the performance of stem cell research in some nations, especially in the US. Here, we hypothesize that this policy influenced specific subfields of the hESC research. To investigate the selective policy effects, we categorize hESC research publications into three subfields—derivation, differentiation, and medical application research. Our analysis shows that restrictive policy had different effects on different subfields. In general, the US outperformed in overall hESC research throughout these periods. In the derivation of hESC, however, the US almost lost its competence under restrictive policy. Interestingly, the US scientific community showed prominent resilience in hESC research through international collaboration. We concluded that the US resilience and performance stemmed from the wide breadth of research portfolio of US scientists across the hESC subfields, combined with their strategic efforts to collaborate internationally on derivation research.     

Stem cell therapies and regenerative medicine in China

Stem cells are the core of tissue repair and regeneration,and a promising cell source for novel therapies.In recent years,research into stem cell therapies has been particularly exciting in China.The remarkable advancements in basic stem cell research and clinically effective trials have led to fresh insights into regenerative medicine,such as treatments for sweat gland injury after burns,diabetes,and liver injury.High hopes have inspired numerous experimental and clinical trials.At the same time,government investment and policy support of research continues to increase markedly.However,numerous challenges must be overcome before novel stem cell therapies can achieve meaningful clinical outcomes.     

干细胞领域研究、开发及市场的全球态势分析

干细胞由于其巨大的研究和应用潜力而成为全球关注焦点。许多国家的政府、研究机构和企业对其加大投入,并取得了巨大的进展。与干细胞相关的论文和专利数量在2001年后均快速增加,其临床和临床前研究的数量也越来越多,但目前仍以脐血干细胞项目为主。美国在干细胞研究领域的各个方面均处于世界顶级地位。中国与干细胞相关的论文和专利数量也居世界前十位,但没有一家机构居世界先进行列,也缺乏新产品研发。面对美国相关政策的放宽所带来的格局变化,中国应该积极应对。     

Stem cell research in China

In the past 5 years, China has increased its efforts in the field of stem cell research and practice. Basic research mainly focuses on bone marrow and embryonic stem cells. Clinical applications of stem cells in the treatment of acute heart failure, acute liver failure and lower limb ischaemia have been reported by many hospitals. China enacted its 'Ethical Guidelines for Human Embryonic Stem Cell Research' in 2003. At present, China has the most liberal and favourable environments for human embryonic stem cell research.     

肿瘤干细胞及肝癌肿瘤干细胞

肿瘤干细胞理论认为只有存在于肿瘤中的少量干细胞性质的细胞群体对肿瘤发生和发展起着决定作用,肿瘤是由干细胞突变积累而形成的无限增殖的异常组织,这一理论的提出使人们对肿瘤发生机制的认识上升到了一个新的高度,也引起了研究者的广泛关注;肝癌是我国常见的恶性肿瘤之一,我国肝癌死亡率居世界之首,目前对肝癌的研究是我国恶性肿瘤防治的重点工作,现对当前肿瘤干细胞与肝癌肿瘤干细胞相关方面的最新研究进展作一概述。     

Stem cells for spine surgery

In the past few years, stem cells have become the focus of research by regenerative medicine professionals and tissue engineers. Embryonic stem cells, although capable of differentiating into cell lineages of all three germ layers, are limited in their utilization due to ethical issues. In contrast, the autologous harvest and subsequent transplantation of adult stem cells from bone marrow, adipose tissue or blood have been experimentally utilized in the treatment of a wide variety of diseases ranging from myocardial infarction to Alzheimer’s disease. The physiologic consequences of stem cell transplantation and its impact on functional recovery have been studied in countless animal models and select clinical trials. Unfortunately, the bench to bedside translation of this research has been slow. Nonetheless, stem cell therapy has received the attention of spinal surgeons due to its potential benefits in the treatment of neural damage, muscle trauma, disk degeneration and its potential contribution to bone fusion.     

Stem cells and regenerative medicine - future perspectives

Stem cell research has expanded at an exponential rate, but its therapeutic applications have progressed much more slowly. Currently, the research focuses on understanding embryonic, adult, and inducible pluripotent stem cells. Translation of adult stem cell research has established a definitive benefit that is greater than that of the current standard of care in the field of cardiovascular medicine. The future of stem cell research and therapy will continue to provide novel avenues of diagnostics, therapeutics, and tissue regeneration. Here we discuss a brief history of stem cell research as it transitioned from the 20th to the 21st century. We address lessons learned in the first decade of the new millennium that could help guide others to translate research into therapy across disciplines. Finally, we highlight future goals and challenges that must be overcome and offer some perspective on the bright future of stem cell research and therapy.     

Stem cell tourism and future stem cell tourists: policy and ethical implications

Stem cell tourism is a small but growing part of the thriving global medical tourism marketplace. Much stem cell research remains at the experimental stage, with clinical trials still uncommon. However, there are over 700 clinics estimated to be operating in mostly developing countries--from Costa Rica and Argentina to China, India and Russia--that have lured many patients, mostly from industrialized countries, driven by desperation and hope, which in turn continue to fuel the growth of such tourism. While much research has focused on such dimensions as the promotions that allow such businesses to make their services known, media coverage, some patient research, and regulatory conditions for developing country clinics, little attention has been paid to the non-affected members of the general population, the future potential users of such services. This empirical study based on five focus group discussions with a diverse group of healthy adults in a Canadian city, explored participant views of patients who use stem cell tourism services, the likelihood they would avail themselves of such services if they were to suffer similar illnesses, and the conditions under which they might do so, and the impact that admonitions and advice from international expert bodies might have on their decisions. Our findings suggest that these healthy adults are sympathetic to the drivers of hope and desperation, and, despite cautions about research limitations, may seek such treatments themselves under similar conditions. These findings are discussed in the context of the policy and ethical issues raised by this form of medical tourism.     

骨髓间充质干细胞免疫抑制作用及其机理

近年来间充质干细胞特殊的免疫学特性越来越引起人们的重视,使其成为移植领域的一个研究热点。许多实验室就间充质干细胞的免疫抑制作用和机理做了大量的研究工作,取得了一定的进展。本文简要综述间充质干细胞的免疫抑制作用和机理。     

中医药参与干细胞研究特色及进展

干细胞因其具有自我更新、在特定的诱导条件下可以分化为多种工作细胞及向损伤组织迁移的能力,受到越来越多研究者的关注。近年来,有关传统中医药参与干细胞的研究已见诸多报道,本文回顾了近年来中医药参与干细胞研究的诸多报道,总结了得出了在中医经典理论指导下中医药参与干细胞研究多以补肾、益气类中药为主,以中药复方、单味中药以及中药有效组分的形式进行研究,结果表明中药可以影响干细胞的生物学特性及功能,能参与完成干细胞动员、迁移、归巢、增殖、分化等各个环节,传统的中医理论可以拓宽干细胞研究的思路,有望解决干细胞研究中的诸多难题,提示中医药在干细胞研究领域中具有较大的潜能,中医药联合干细胞治疗在临床应用中具有较大的应用前景。     

世界主要国家的干细胞研究最新动态

介绍了主要国家干细胞研究的政策支持、成果产出及市场需求动态。利用SCI引文数据库和Derwent数据库收录的论文和专利信息,对1995年~2008年主要国家干细胞研究的论文和专利进行了分析,以供我国干细胞研究者参考。     

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     

Systems Bioethics and Stem Cell Biology

The complexities of modern science are not adequately reflected in many bioethical discussions. This is especially problematic in highly contested cases where there is significant pressure to generate clinical applications fast, as in stem cell research. In those cases a more integrated approach to bioethics, which we call systems bioethics, can provide a useful framework to address ethical and policy issues. Much as systems biology brings together different experimental and methodological approaches in an integrative way, systems bioethics integrates aspects of the history and philosophy of science, social and political theory, and normative analysis with the science in question. In this paper we outline how a careful analysis of the science of stem cell research can help to refocus the discussions related to the clinical applications of stem cells. We show how inaccurate or inadequate scientific assumptions help to create a set of unrealistic expectations and badly inform ethical deliberations and policy development. Systems bioethics offers resources for moving beyond the current impasse.     

Stem Cell Research: A Novel Boulevard towards Improved Bovine Mastitis Management

The dairy industry is a multi-billion dollar industry catering the nutritional needs of all age groups globally through the supply of milk. Clinical mastitis has a severe impact on udder tissue and is also an animal welfare issue. Moreover, it significantly reduces animal value and milk production. Mammary tissue damage reduces the number and activity of epithelial cells and consequently contributes to decreased milk production. The high incidence, low cure rate of this highly economic and sometimes deadly disease is an alarming for dairy sector as well as policy makers. Bovine mammary epithelial cells (MECs) and their stem cells are very important in milk production and bioengineering. The adult mammary epithelium consists of two main cell types; an inner layer of luminal epithelial cells, which produce the milk during lactation, and an outer layer of myoepithelial cells resting on a basement membrane, which are responsible for pushing the milk through the ductal network to the teat cistern. Inner layer of columner/luminal cells of bovine MECs, is characterized by cytokeratin18, 19 (CK18, CK19) and outer layer such as myoepithelial cells which are characterized by CK14, α-smooth muscle actin (α-SMA) and p63. Much work has been done in mouse and human, on mammary gland stem cell research, particularly in cancer therapy, but stem cell research in bovine is still in its infancy. Such stem/progenitor cell discoveries in human and mouse mammary gland bring some hope for application in bovines. These progenitors may be therapeutically adopted to correct the structural/cytological defects in the bovine udder due to mastitis. In the present review we focused on various kinds of stem/progenitor cells which can have therapeutic utility and their possibilities to use as a potential stem cell therapy in the management of bovine post-mastitis damage in orders to restore milk production. The possibilities of bovine mammary stem cell therapy offers significant potential for regeneration of tissues that can potentially replace/repair diseased and damaged tissue through differentiation into epithelial, myoepithelial and/or cuboidal/columnar cells in the udder with minimal risk of rejection and side effects.     

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.     

Stem cells assessed

The increasing momentum of stem cell research continues, with the better characterization of induced pluripotent stem (iPS) cells, the conversion of differentiated cells into different cell types and the use of pluripotent stem cells to generate whole tissues, among other advances. Here, six experts in the field of stem cell research compare different stem cell models and highlight the importance of pursuing complementary experimental approaches for a better understanding of pluripotency and differentiation and an informed approach to medical applications.     

Stem cell applications for pathologies of the urinary bladder

New stem cell based therapies are undergoing intense research and are widely investigated in clinical fields including the urinary system. The urinary bladder performs critical complex functions that rely on its highly coordinated anatomical composition and multiplex of regulatory mechanisms. Bladder pathologies resulting in severe dysfunction are common clinical encounter and often cause significant impairment of patient’s quality of life. Current surgical and medical interventions to correct urinary dysfunction or to replace an absent or defective bladder are sub-optimal and are associated with notable complications. As a result, stem cell based therapies for the urinary bladder are hoped to offer new venues that could make up for limitations of existing therapies. In this article, we review research efforts that describe the use of different types of stem cells in bladder reconstruction, urinary incontinence and retention disorders. In particular, stress urinary incontinence has been a popular target for stem cell based therapies in reported clinical trials. Furthermore, we discuss the relevance of the cancer stem cell hypothesis to the development of bladder cancer. A key subject that should not be overlooked is the safety and quality of stem cell based therapies introduced to human subjects either in a research or a clinical context.     

Stem cell colloquy: conclusion

The stem cell data presented and discussed during the symposium raise the hope that important medical progress can be made in several fields: neuro-degenerative diseases, those linked to cellular deficit, some aspects of aging linked to cellular degeneration, and the treatment of cancers that may harm normal tissues at risk of being infiltrated by malignant cells. Three main types of stem cells are available. (i) Those present in normal adult tissue: contrary to what was believed, some data suggest that certain adult stem cells have a great plasticity (they can differentiate into cells different from those in tissues from which they were taken) and can proliferate in vitro without losing their properties. Nevertheless, their use faces several obstacles: in ill or elderly subjects, then these cells can be limited in number or not multiply well in vitro. In this case, auto-grafting of the cells cannot be used. They must be sought in another subject, and allo-grafting causes difficult and sometimes insoluble problems of immunological tolerance. (ii) Embryonic stem cells from surplus human embryos, obtained by in vitro fertilisation, which the parents decide not to use: these cells have a great potential for proliferation and differentiation, but can also encounter problems of immunological intolerance. (iii) Cells obtained from cell nuclear transfer in oocytes: these cells are well tolerated, since they are genetically and immunologically identical to those of the host. All types of stem cells can be obtained with them. However, they do present problems. For obtaining them, female oocytes are needed, which could lead to their commercialization. Moreover, the first steps for obtaining these cells are identical to those used in reproductive cloning. It therefore appears that each type of cell raises difficult scientific and practical problems. More research is needed to overcome these obstacles and to determine which type of stem cell constitutes the best solution for each type of disease and each patient. There are three main ethical problems: (a) to avoid the commercialization of stem cells and oocytes (this can be managed through strict regulations and the supervision of authorized laboratories); (b) to avoid that human embryos be considered as a mere means to an end (they should only be used after obtaining the informed consent of the parents; the conditions of their use must be well defined and research programs must be authorized); (c) to avoid that research on stem cell therapy using cell nuclear replacement opens the way to reproductive cloning (not only should reproductive cloning be firmly forbidden but authorization for cell nuclear transfer should be limited to a small number of laboratories). Overall, it appears that solutions can be found for administrative and ethical problems. Harmonisation of international regulations would be desirable in this respect, in allowing at the same time each country to be responsible for its regulations. A last ethical rule should be implemented, not to give patients and their families false hopes. The scientific and medical problems are many, and the solutions will be long and difficult to find. Regenerative medicine opens important avenues for research, but medical progress will be slow.