A stem cell ... is stem cell?

We are used to associate stem cells with renewable tissues such as blood, gut and skin. But some cells in the adult central nervous system have the capacity to generate new neurons and glial cells as well and as such, they are considered to be neural stem cell. Yet their ability to generate neurons and glia, and their presence in the central nervous system throughout life, suggests new, intriguing possibilities for recovery and repair after damage to the central nervous system--and unexpectedly, the regeneration of blood tissues. After transplantation into irradiated hosts, neural stem cells were found to produce a variety of blood cell types including myeloid and lymphoid cells as well as early hematopoietic cells. Therefore, the developmental potential of stem cells is not restricted to the differentiated elements of the tissue in which they reside. Multipotential stem cells can persist in an undifferentiated state, and depending on specific environmental conditions function as a stem cell for many different tissues.     

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.     

Male germ line stem cells: from cell biology to cell therapy

Research using stem cells has several applications in basic biology and clinical medicine. Recent advances in the establishment of male germ line stem cells provided researchers with the ability to identify, isolate, maintain, expand and differentiate the spermatogonia, the primitive male germ cells, as cell lines under in vitro conditions. The ability to culture and manipulate stem cell lines from male germ cells has gradually facilitated research into spermatogenesis and male infertility, to an extent beyond that facilitated by the use of somatic stem cells. After the introduction of exogenous genes, the spermatogonial cells can be transplanted into the seminiferous tubules of recipients, where the transplanted cells can contribute to the offspring. The present review concentrates on the origin, life cycle and establishment of stem cell lines from male germ cells, as well as the current status of transplantation techniques and the application of spermatogonial stem cell lines.     

Oxidative stress-induced biomarkers for stem cell-based chemical screening

Stem cells have been considered for their potential in pharmaceutical research, as well as for stem cell-based therapy for many diseases. Despite the potential for their use, the challenge remains to examine the safety and efficacy of stem cells for their use in therapies. Recently, oxidative stress has been strongly implicated in the functional regulation of cell behavior of stem cells. Therefore, development of rapid and sensitive biomarkers, related to oxidative stress is of growing importance in stem cell-based therapies for treating various diseases. Since stem cells have been implicated as targets for carcinogenesis and might be the origin of “cancer stem cells”, understanding of how oxidative stress-induced signaling, known to be involved in the carcinogenic process could lead to potential screening of cancer chemopreventive and chemotherapeutic agents. An evaluation of antioxidant states reducing equivalents like GSH and superoxide dismutase (SOD), as well as reactive oxygen species (ROS) and nitric oxide (NO) generation, can be effective markers in stem cell-based therapies. In addition, oxidative adducts, such as 4-hydroxynonenal, can be reliable markers to detect cellular changes during self-renewal and differentiation of stem cells. This review highlights the biomarker development to monitor oxidative stress response for stem cell-based chemical screening.     

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。     

Somatische Stammzellen Grundlagen, Konzepte und Herausforderungen

Adult stem cells are multipotent cells that have the ability to self-renew and to differentiate into highly specialized cells. Differentiation of specific cells is not limited to early embryonic development. It also takes place within the adult organism. Adult stem are found in tissues and organs showing a high turn-over rate such as blood, skin or intestine. Moreover, tissues like liver or skin are able to regenerate after injury, indicating the presence of stem cells within these organs. Whereas blood stem cells are already used in transplantation medicine, the biology and therapeutic potential of stem cells isolated from other tissues are still under investigation. Currently, research is focused on the identification and analysis of the factors regulating stem cell self-renewal and differentiation. A better understanding of stem cell biology certainly will lead to new therapeutic concepts, i.e. the use of stem cells and/or their derivatives as replacement cells to treat diseases including for example diabetes, Parkinson's disease, spinal cord injury, stroke, burns, rheumatoid arthritis.     

Circulating stem cells and tissue repair

Stem cells are defined as cells that have clonogenic, self-renewing capacities and the capability to differentiate into multiple cell lineages. Whereas embryonic stem cells are derived from mammalian embryos in the blastocyst stage and can generate terminally differentiated cells of all 3 embryonic germ layers, adult human stem cells are capable of maintaining, generating, and replacing terminally differentiated cells within their own specific tissue as a consequence of physiologic cell turnover or tissue injury. The traditional idea of organ-restricted stem-cell differentiation is now being challenged by the suggestion that adult stem cells retain developmental plasticity. Preclinical and clinical studies described in this review provide evidence that within the blood circulate not only progenitor cells that differentiate into hematopoietic cells, but also stem/progenitor cells which can participate in the homeostasis, repair and replacement of solid organ tissues. In addition to the occurrence of cell fusion, there are 4 suggested mechanisms of adult stem cell differentiation into solid organ cells. Preclinical data support these models particularly that of transdifferentiation as the most likely model, allowing stem/progenitor cells to differentiate across lineage, tissue, and germ layer boundaries. There is increasing evidence that we can manipulate in vivo circulating adult stem cells to repair or regenerate solid organ tissue, which offers potential clinical benefit in the treatment of many hereditary and acquired diseases.     

肝癌干细胞差异表达miRNA的筛选及鉴定

目的培养卵圆细胞、肝癌干细胞样细胞,筛选肝癌干细胞差异表达的microRNA并进行验证。方法体外分离培养卵圆细胞,肝癌干细胞样细胞,通过microRNA芯片检测差异表达的microRNA,对所得到的差异表达显著的microRNA进行Northern验证。结果表达差异显著的microRNA共有17个,经Northem杂交验证,其中6个差异显著的microRNA,发现hsa—let-7f-2、hsa—miR-199a-3p、hsa-miR-122在肝癌干细胞中的表达较卵圆细胞明显升高。结论hsa—let一7f-2、hsa—miR-199a一3p、hsa—miR-122在肝癌干细胞中的表达较卵圆细胞明显升高,可以进一步验证其在肝癌于细胞中的功能。     

Prospects for cell-based therapies for liver disease

Liver parenchymal maintenance and regeneration after injury are physiologically supported by 3 cell compartments: mature liver cells, intra-organ stem cells such as cells of the proximal biliary tree and periductal cells, and extra-organ stem cells from the circulation and the bone marrow. In the latter case, hepatocyte derivation from circulating cells (plasticity) can arise via direct transdifferentiation (site specific, receptor/ligand dependent) or by fusion of circulating cells with pre-existing hepatocytes. Other non-physiologic stem cells, such as mesenchymal stem cells from the bone marrow and embryonic stem cells, may be potentially used in treatment of inherited and acquired liver diseases. This review updates our current understanding of these various cell populations and of possible approaches to their future therapeutic uses in cell transplantation, bioartificial liver devices, cytokine/chemokines manipulation of physiological repair pathways, and gene therapy.     

Stem cell theory of colorectal cancer and its connection with molecular-biological data

Colorectal cancer is the second leading cause of death in Hungary as well as in the developed countries. The high cancer prevalence of the gastrointestinal tract is the result of the rapid turnover of epithelial cells and exposure to dietary toxins. Adult stem cells are in the lime-light of the medicine. The adult stem cells and tumor cells resemble to each other on the basis of their properties, like self-renewal and proliferation. Cancer is believed to be a disease of stem cells. Recent years have seen major advances in our understanding of location (niche), life cycle, regulation (Wnt/beta-catenin signaling pathway) and markers (mathusashi-1, beta-catenin) of gastrointestinal stem cells. The exact role of adult stem cells in intestinal carcinogenesis is open for debate. New works suggest the role for inflammation-induced engraftment of circulating marrow-derived stem cells in colorectal carcinogenesis. The causes of malignant transformation of local or engrafting bone marrow-derived stem cells are mutations (APC, MMR genes) or methylation (CDKN2A, p16/INK4a, MGMT, MLH1). The spread of dysplastic cells (bottom-up, top-down hypothesis) is also ambiguous.     

肿瘤干细胞与卵巢癌研究进展

近年肿瘤干细胞理论及其相关研究引起关注。该理论认为,肿瘤干细胞是恶性肿瘤发生、耐药、复发及转移的根源,并最终导致恶性肿瘤靶向治疗失败,难以根治。卵巢癌治疗的最大障碍是肿瘤细胞耐药性的产生,肿瘤干细胞的研究对解决卵巢癌等恶性肿瘤的高耐药、复发难题有重要意义。目前,卵巢癌干细胞已经成功分离鉴定,但此方面的研究尚处于开始阶段。从肿瘤干细胞角度对卵巢癌干细胞的性质及分离鉴定方法综述。     

广西某纺织企业女工生殖道感染状况及影响因素分析

目的 了解广西纺织企业女工生殖道感染(RTIs)现状,分析影响女工RTIs的危害因素,为制定健康保护和劳动防护策略提供依据.方法 采用横断面调查,通过整群抽样法选取广西某纺织企业女工进行问卷调查,采用x2检验和非条件二分类多因素Logistic回归分析影响女工RTIs的危害因素.结果 在592名纺织女工中,有156人(...     

干细胞向雌性生殖细胞分化的研究进展

干细胞是一类具有自我更新和多向分化潜能的细胞。根据其来源不同,干细胞可分为胚胎干细胞、成体干细胞以及诱导性多能干细胞。生殖细胞系负责跨代传递遗传和表观遗传信息,以确保新的正常个体产生。人类辅助生殖技术(ART)虽可解决部分难治性不孕不育患者的生育问题,但尚不能解决由于卵巢早衰生殖细胞缺乏导致的不孕,如果在体外可以将干细胞定向诱导分化为生殖细胞,则可能通过ART帮助卵巢早衰患者获得健康后代。雌性配子发育经历了多个严格、复杂的过程,包括原始生殖细胞(PGC)特化、增殖、迁移到生殖嵴并最终分化为成熟的卵母细胞。然而具体过程尚不明确。近年来学者已建立了干细胞向雌性生殖细胞分化的体外模型,并取得了长足进步。     

Somatische Stammzellen des zentralen Nervensystems

During neural development, the nervous system is created from stem cells that have the potential to proliferate, to reproduce (self-renew) themselves, and to differentiate into the appropriate neuronal and glial phenotypes. Although the adult brain has traditionally been thought of as a structure with very limited regenerative capacity, these neural stem cells have recently been shown to exist in the adult central nervous system (CNS) as well. In vitro and following transplantation, neural stem cells obtained from the fetal and adult brain are able to generate neurons, astrocytes, and oligodendrocytes, the three major CNS cell types. Therefore, neural stem cells are potential sources for specialized neural cells needed to treat a variety of neurological disorder. The present review describes how somatic stem cells of the central nervous system can be cultivated in vitro and to which extend stem cell transplantation is effective in animal models for neurological diseases. Finally, a perspective is given on the potential clinical use of human neural stem cells for the treatment of neurological diseases.     

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。     

Spermatogonia: origin, physiology and prospects for conservation and manipulation of the male germ line

In recent years, the scientific community has become increasingly interested in spermatogonia. Methodological breakthroughs, such as germ cell transplantation and spermatogonial culture combined with novel germ line transfection strategies, have provided interesting new opportunities for studying the physiology of spermatogonial stem cells and their interaction with the stem cell niche. Furthermore, intense research into pluripotent and adult stem cells has generated new insight into the differentiation pathway of germ line stem cells and has opened new perspectives for stem cell technologies. The present review briefly introduces the physiology of spermatogonial stem cells and discusses future directions of basic research and practical approaches applicable to livestock maintenance and animal reproduction.     

干细胞临床使用有效性和安全性及其对监管的启示

目的分析不同类型干细胞临床使用的有效性和安全性,为政府监管干细胞临床使用提供依据。方法检索国内外6个文献数据库以获取2010年1月—2020年7月的相关研究文献,并进行系统性综述。结果72篇纳入文献涉及干细胞临床使用的有效性与安全性。虽然干细胞临床使用对部分疾病具有一定的治疗效果,但其长期疗效与安全性、尤其是致瘤性等潜在风险仍需进一步评估。结论临床医师应充分权衡干细胞临床使用的获益与风险,政府相关部门应加强对干细胞临床研究与应用的伦理监管和干细胞产品上市的监管,以保障患者权益。     

干细胞治疗子宫内膜损伤的研究进展

感染因素或宫腔手术操作导致的子宫内膜损伤阻碍胚胎的着床和发育,严重影响妇女的身心健康与生育能力。但目前治疗手段有限且效果欠佳。干细胞具有自我更新和分化潜能,在病变损伤组织的修复过程中发挥重要作用。骨髓间充质干细胞、脐带间充质干细胞、子宫内膜干细胞、脂肪干细胞和人羊膜上皮细胞等多种干细胞治疗子宫内膜损伤已在动物模型和临床研究中开展,并展现出巨大的潜力。干细胞治疗可促进子宫内膜细胞再生,改善子宫内膜厚度和微血管密度,提高受孕率并改善生育结局。干细胞治疗从形态和功能上改善子宫内膜,促进月经和生殖功能的恢复,为治疗子宫内膜损伤提供一种新策略。     

Stem cells: hype and hope

There is increasing interest in the use of stem cells for therapeutic purposes. The use of embryonic stem cells carries ethical and legal restrictions that limit their role in tissue regeneration. These restrictions do not apply to somatic stem cells, such as haematopoietic stem cells, which normally reside in the bone marrow. Preclinical studies have produced very promising results using these cells in experimental models of myocardial infarction. Bone-marrow cells have also been used to generate several different types of tissue. However, experimental data suggest that bone marrow also houses other non-haematopoietic stem cells, which could account for the alleged plasticity of haematopoietic stem cells. So far, the results of randomised clinical trials in patients with myocardial infarction or heart failure have been disappointing. It is clear that further research in this field is needed.