Human Embryonic Stem Cells

Sox2 has yet to be determined. Sox2 can act synergistically with Oct3/4 in vitro to activate Oct-Sox enhancers, which regulate the expression of pluripotent stem cellspecific genes, including Nanog, Oct3/4 and Sox2 itself. These findings suggest that Sox2 is required by ES cells for its Oct-Sox enhancer activity. Using inducible Sox2-null mouse ES cells, we show that Sox2 is dispensable for the activation of these Oct-Sox enhancers. In contrast, we demonstrate that Sox2 is necessary for regulating multiple transcription factors that affect Oct3/4 expression and that the forced expression of Oct3/4 rescues the pluripotency of Sox2-null ES cells. These results indicate that the essential function of Sox2 is to stabilize ES cells in a pluripotent state by maintaining the requisite level of Oct3/4 expression.

The derivation of neural progenitor cells from human embryonic stem (ES) cells is of value both in the study of early human neurogenesis and in the creation of an unlimited source of donor cells for neural transplantation therapy. Here we report the generation of enriched and expandable preparations of proliferating neural progenitors from human ES cells. The neural progenitors could

Background: The use of embryos in embryonic stem cell research (ESCR) has elicited ethical controversies as it entails the destruction of 5-day old human embryos to harvest stem cells. Objective: To explore the ethical positions of Islam, Buddhism, Hinduism, and Catholicism concerning the use of (1) left-over embryos from in vitro fertilization (IVF) also known as ‘surplus’ embryos and (2) ‘research embryos’ which are created by scientists to conduct research using embryonic stem cells. Methods: The opinions of religious leaders of Buddhist, Hindu, and Catholic faiths in Malaysia pertaining to ESCR were examined via in-depth, semi-structured interviews while Islamic responses are collected from local writings related to the derivation of fatwa on this issue. Participants’ responses on the ethics of human stem cell research are presented as a reflection of various scriptural texts of these four religions. These are presented and supported with the help of international bioethics lite...

Oct4 and Nanog are transcription factors required to maintain the pluripotency and self-renewal of embryonic stem (ES) cells. Using the chromatin immunoprecipitation paired-end ditags method, we mapped the binding sites of these factors in the mouse ES cell genome. We identified 1,083 and 3,006 high-confidence binding sites for Oct4 and Nanog, respectively. Comparative location analyses indicated that Oct4 and Nanog overlap substantially in their targets, and they are bound to genes in different configurations. Using de novo motif discovery algorithms, we defined the cis-acting elements mediating their respective binding to genomic sites. By integrating RNA interference-mediated depletion of Oct4 and Nanog with microarray expression profiling, we demonstrated that these factors can activate or suppress transcription. We further showed that common core downstream targets are important to keep ES cells from differentiating. The emerging picture is one in which Oct4 and Nanog control a cascade of pathways that are intricately connected to govern pluripotency, self-renewal, genome surveillance and cell fate determination.

The International Stem Cell Initiative characterized 59 human embryonic stem cell lines from 17 laboratories worldwide. Despite diverse genotypes and different techniques used for derivation and maintenance, all lines exhibited similar expression patterns for several markers of human embryonic stem cells. They expressed the glycolipid antigens SSEA3 and SSEA4, the keratan sulfate antigens TRA-1-60, TRA-1-81, GCTM2 and GCT343, and the protein antigens CD9, Thy1 (also known as CD90), tissue-nonspecific alkaline phosphatase and class 1 HLA, as well as the strongly developmentally regulated genes NANOG, POU5F1 (formerly known as OCT4), TDGF1, DNMT3B, GABRB3 and GDF3. Nevertheless, the lines were not identical: differences in expression of several lineage markers were evident, and several imprinted genes showed generally similar allelespecific expression patterns, but some gene-dependent variation was observed. Also, some female lines expressed readily detectable levels of XIST whereas others did not. No significant contamination of the lines with mycoplasma, bacteria or cytopathic viruses was detected.

In addition to their potential for cell-based therapies in the treatment of disease and injury, the broad developmental capacity of human embryonic stem cells (hESCs) offers potential for studying the origins of all human cell types. To date, the emergence of specialized cells from hESCs has commonly been studied in tissue culture or in teratomas, yet these methods have stopped short of demonstrating the ESC potential exhibited in the mouse (mESCs), which can give rise to every cell type when combined with blastocysts. Due to obvious barriers precluding the use of human embryos in similar cell mixing experiments with hESCs, human/non-human chimeras may need to be generated for this purpose. Our results show that hESCs can engraft into mouse blastocysts, where they proliferate and differentiate in vitro and persist in mouse/human embryonic chimeras that implant and develop in the uterus of pseudopregnant foster mice. Embryonic chimeras generated in this way offer the opportunity to study the behavior of specialized human cell types in a non-human animal model. Our data demonstrate the feasibility of this approach, using mouse embryos as a surrogate for hESC differentiation.

Her research focuses on human embryonic implantation, uterine receptivity and embryonic stem cells, leading to the publication of 26 peer-reviewed papers. She received awards from the American Fertility Society in 1997 and the Spanish Society of Obstetrics and Gynecology in 1998.

Nearly 20 years after murine embryonic stem cells (mESC) were isolated, the first report of the derivation of human embryonic stem cells (hESC) in 1998 spawned the field of hESC research [Evans MJ, Kaufman MH, Establishment in culture of pluripotential cells from mouse embryos. Nature 1981;292(5819): 154-6; Thomson JA, Itskovitz-Eldor J, Shapiro SS, et al. Embryonic stem cell lines derived from human blastocysts. Science 1998;282(5391):1145-7].

Background: The use of embryos in embryonic stem cell research (ESCR) has elicited ethical controversies as
it entails the destruction of 5-day old human embryos to harvest stem cells.
Objective: To explore the ethical positions of Islam, Buddhism, Hinduism, and Catholicism concerning the use
of (1) left-over embryos from in vitro fertilization (IVF) also known as ‘surplus’ embryos and (2) ‘research embryos’
which are created by scientists to conduct research using embryonic stem cells.
Methods: The opinions of religious leaders of Buddhist, Hindu, and Catholic faiths in Malaysia pertaining to
ESCR were examined via in-depth, semi-structured interviews while Islamic responses are collected from local
writings related to the derivation of fatwa on this issue. Participants’ responses on the ethics of human stem cell
research are presented as a reflection of various scriptural texts of these four religions. These are presented and
supported with the help of international bioethics literature and focus on the use of ‘surplus’ embryos and
‘research’ embryos.
Results: Islamic ethics deviate from Hindu and Buddhist teachings regarding saving of research embryos that
have been created specifically for research and are considered as human lives only after 120 days fertilization.
Hindu and Buddhists also underscore the sanctity of human life, but give priority to the alleviation of suffering
in living adult humans. They generally encourage ESCR. Research is a knowledge-seeking endeavor considered
noble by Islam. This is also a concept within Hindu and Buddhist philosophy; in particular, when potentially
beneficial research goals are the basis. Catholicism also emphasizes sanctity of human life, but stresses also
the inviolability of embryos from the moment of conception.
Conclusion: Embryonic stem cell research is permissible and encouraged according to Hindu and Buddhist
perspectives in view of the potential benefits of such research to society, with some reservations. This is similar
to Islamic views on the ethics of ESCR. However, Catholicism differs from all the other three religions; it appears
to discourage research in this field because of the likely violation of a sacred principle in Catholic teachings.

Sommario: 1. Le tre questioni pregiudiziali relative all’interpretazione del divieto di brevettare «utilizzazioni di embrioni umani a fini industriali o commerciali». – 2. Autonomia del significato giuridico di embrione rispetto al contributo valutativo della scienza. – 3. Apertura della Corte di giustizia a un’idea del diritto quale fenomeno culturale e abbandono del canone dell’interpretazione letterale. – 4. Ragioni a fondamento di un’interpretazione autonoma e uniforme, nello spazio giuridico europeo, della nozione di embrione. – 5. Segue. Diversità delle definizioni di embrione offerte dai diritti nazionali. Ispirazione della tutela riconosciuta al concepito nell’ordinamento italiano al principio di unità e continuità del processo vitale. – 6. Attitudine del criterio teleologico ad assicurare la prevalenza di scopi mercantilisti e conseguente (potenziale) accoglimento di un’interpretazione restrittiva che permetta di impiegare, per scopi di ricerca, embrioni umani nelle prime fasi di sviluppo biologico. – 7. Ottimizzazione del valore della dignità umana e impostazione personalista della questione interpretativa della nozione di embrione. Verso un’ermeneutica assiologicamente orientata della Corte di giustizia.

Continuous immunosuppressive treatment allows the majority of transplant recipients to accept their donated organ and prevent acute graft rejection. However, life-long suppression of the immune system to respond appropriately to infectious, fungal, and carcinogenic threats coincides with substantial morbidity and mortality for the host. Thus for the past five decades research in the field of transplantation medicine has focused on innovative strategies to induce graft tolerance to donor alloantigens, a state in which the recipient's lymphocytes have learned to accept the foreign organ or tissue as "self" without the need of permanent immunosuppression. The fact that individuals of the same species attack each other's tissues can be explained with the set of specific antigens, designated as major histocompatibility antigens, which are expressed on each cell of the body and normally widely differ between nonrelated individuals. According to the genetic laws of transplantation, survival of allogeneic grafts is correlated with the number of differences among these histocompatibility antigens. An important exception to this rule can be observed in pregnant women who tolerate their unborn conceptus expressing a full set of nonmaternal antigens inherited by the father. The exact mechanisms of immune privilege exhibited by embryonic tissue during prenatal development have not yet been characterized in each detail. The field of maternofetal immunobiology has lately emerged as a new scientific branch in immunology which is gathering useful insights for future innovative tolerance strategies to prevent allogeneic graft rejection.

could facilitate the assessment of the true contribution of various experimental parameters on recovery. We conclude that at present embryonic stem (ES)-derived cells hold the most promise for therapeutic utility, but that non-neural cells may ultimately be optimal if the mechanism of possible transdifferentiation can be elucidated.

The objective of this paper is to explore the Buddhist position particularly within the Mahāyāna sect about the use of human embryos which may be either surplus embryos thawed in the laboratory or embryos cultured for research purposes. Buddhism does not give prominence to any supreme creation whose plan might be distorted by human intervention with nature. Buddhism postulates the cyclic course of human existence as eternal. There is no starting point to the series of lives lived and obviously there is no end. In the Buddhist thought, there is a belief that every individual had existence prior to the present birth. Following this, the paper made a study of the details of the conception and gestation as found in the Buddhist literature and sources. Buddhism aims to do away with pain. Intention is an intrinsic aspect in Buddhism referred to as sankalpa, which is beyond mere goals and objectives. An action is deemed as good karma because of its intentions. To Buddhism, a selfless action gains significance.

Tissue engineering (TE) is a promising new field of medical technology. However, like other new technologies, it is not free of ethical challenges. Identifying these ethical questions at an early stage is not only part of science's responsibility toward society, but also in the interest of the field itself. In this review, we map which ethical issues related to TE have already been documented in the scientific literature. The issues that turn out to dominate the debate are the use of human embryonic stem cells and therapeutic cloning. Nevertheless, a variety of other ethical aspects are mentioned, which relate to different phases in the development of the field. In addition, we discuss a number of ethical issues that have not yet been raised in the literature.

Mammalian embryo splitting has successfully been established in farm animals. Embryo splitting is safely and efficiently used for assisted reproduction in several livestock species. In the mouse, efficient embryo splitting as well as single blastomere cloning have been developed in this animal system. In nonhuman primates embryo splitting has resulted in several pregnancies. Human embryo splitting has been reported recently.

Tissue engineering is a newly emerging biomedical technology, which aids and increases the repair and regeneration of deficient and injured tissues. It employs the principles from the fields of materials science, cell biology, transplantation, and engineering in an effort to treat or replace damaged tissues. Tissue engineering and development of complex tissues or organs, such as heart, muscle, kidney, liver, and lung, are still a distant milestone in twenty-first century. Generally, there are four main challenges in tissue engineering which need optimization. These include biomaterials, cell sources, vascularization of engineered tissues, and design of drug delivery systems. Biomaterials and cell sources should be specific for the engineering of each tissue or organ. On the other hand, angiogenesis is required not only for the treatment of a variety of ischemic conditions, but it is also a critical component of virtually all tissue-engineering strategies. Therefore, controlling the dose, location, and duration of releasing angiogenic factors via polymeric delivery systems, in order to ultimately better mimic the stem cell niche through scaffolds, will dictate the utility of a variety of biomaterials in tissue regeneration. This review focuses on the use of polymeric vehicles that are made of synthetic and/or natural biomaterials as scaffolds for three-dimensional cell cultures and for locally delivering the inductive growth factors in various formats to provide a method of controlled, localized delivery for the desired time frame and for vascularized tissue-engineering therapies.

The million frozen human embryos accumulated in IVF clinic freezers across the United States have become premier targets for saving by groups committed to repurposing reproductive remainders. Based on twenty-seven months (2008-2013) of ethnographic research within a Christian embryo adoption program and an embryo biobank for stem cell research, this article examines the motivations and practices involved in transforming leftover IVF embryos from a remaindered to a repurposed state. A focus on saving illuminates how moral discourses, economic logics, and biomedical issues conspire in shaping futures as well as modes of care in the present. Embryo repurposing programs use similar saving practices for different reasons, assume responsibility for repurposing IVF embryos, and strive to transform them into revalued forms for new futures. Fluctuating factors beyond the cryopreservation tank multiply rather than stabilize embryo potential. As a dynamic, open-ended process, saving requires programs to adjust strategies over time and wait.

Mouse embryonic stem (ES) cells were used as an experimental model to study the effects of electromagnetic fields (EMF). ES-derived nestin-positive neural progenitor cells were exposed to extremely low frequency EMF simulating power line magnetic fields at 50 Hz (ELF-EMF) and to radiofrequency EMF simulating the Global System for Mobile Communication (GSM) signals at 1.71 GHz (RF-EMF). Following EMF exposure, cells were analyzed for transcript levels of cell cycle regulatory, apoptosis-related, and neural-specific genes and proteins; changes in proliferation; apoptosis; and cytogenetic effects. Quantitative RT-PCR analysis revealed that ELF-EMF exposure to ES-derived neural cells significantly affected transcript levels of the apoptosis-related bcl-2, bax, and cell cycle regulatory "growth arrest DNA damage inducible" GADD45 genes, whereas mRNA levels of neural-specific genes were not affected. RF-EMF exposure of neural progenitor cells resulted in down-regulation of neural-specific Nurr1 and in up-regulation of bax and GADD45 mRNA levels. Short-term RF-EMF exposure for 6 h, but not for 48 h, resulted in a low and transient increase of DNA double-strand breaks. No effects of ELF-and RF-EMF on mitochondrial function, nuclear apoptosis, cell proliferation, and chromosomal alterations were observed. We may conclude that EMF exposure of ES-derived neural progenitor cells transiently affects the transcript level of genes related to apoptosis and cell cycle control. However, these responses are not associated with detectable changes of cell physiology, suggesting compensatory mechanisms at the translational and posttranslational level.

Background: Under appropriate culture conditions, undifferentiated embryonic stem (ES) cells can undergo multiple selfrenewal cycles without loss of pluripotency suggesting they must be equipped with specific defense mechanisms to ensure sufficient genetic stability during self-renewal expansion. The ATP binding cassette transporter ABCG2 is expressed in a wide variety of somatic and embryonic stem cells. However, whether it plays an important role in stem cell maintenance remains to be defined.

STK15/Aurora2 is a centrosome-associated serine/threonine kinase, the protein levels and kinase activity of which rise during G2 and mitosis. STK15 overexpression induces tumorigenesis and is amplified in various human cancers and tumor cell lines. Thus, STK15 represents an important therapeutic target for small molecule inhibitors that would disrupt its activity and block cell proliferation. The availability of a robust and selective small molecule inhibitor would also provide a useful tool for identification of the potential role of STK15 in cell cycle regulation and tumor development. The authors report the development of a novel, fast, simple microplate assay for STK15 activity suitable for high-throughput screening. In the assay, γ-33 P-ATP and STK15 were incubated in a myelin basic protein (MBP)-coated FlashPlate® to generate a scintillation signal. The assay was reproducible, the signal-to-noise ratio was high (11) and the Z′ factor was 0.69. The assay was easily adapted to a robotic system for drug discovery programs targeting STK15. The authors also demonstrate that STK15 is regulated by phosphorylation and the N-amino terminal domain of the protein. Treatment with phosphatase inhibitors (okadaic acid) or deletion of the Namino terminal domain results in a significant increase in the enzymatic activity. (Journal of Biomolecular Screening 2004:391-397)

The mammalian nervous system exerts essential control on many physiological processes in the organism and is itself controlled extensively by a variety of genetic regulatory mechanisms. microRNA (miR), an abundant class of small non-coding RNA, are emerging as important post-transcriptional regulators of gene expression in the brain. Increasing evidence indicates that miR regulate both the development and function of the nervous system. Moreover, deficiency in miR function has also been implicated in a number of neurological disorders. Expression profile analysis of miR is necessary to understand their complex role in the regulation of gene expression during the development and differentiation of cells. Here we present a comparative study of miR expression profiles in neuroblastoma, in cortical development, and in neuronal differentiation of embryonic stem (ES) cells. By microarray profiling in combination with real time PCR we show that miR-7 and miR-214 are modulated in neuronal differentiation (as compared to miR-1, -16 and -133a), and control neurite outgrowth in vitro. These findings provide an important step toward further elucidation of miR function and miR-related gene regulatory networks in the mammalian central nervous system.

Human embryonic germ cells (EGCs) provide a powerful model for identifying molecules involved in the pluripotent state when compared to their progenitors, primordial germ cells (PGCs), and other pluripotent stem cells. Microarray and Principal Component Analysis (PCA) reveals for the first time that human EGCs possess a transcription profile distinct from PGCs and other pluripotent stem cells. Validation with qRT-PCR confirms that human EGCs and PGCs express many pluripotency-associated genes but with quantifiable differences compared to pluripotent embryonic stem cells (ESCs), induced pluripotent stem cells (IPSCs), and embryonal carcinoma cells (ECCs). Analyses also identified a number of target genes that may be potentially associated with their unique pluripotent states. These include IPO7, MED7, RBM26, HSPD1, and KRAS which were upregulated in EGCs along with other pluripotent stem cells when compared to PGCs. Other potential target genes were also found which may contribute toward a primed ESC-like state. These genes were exclusively upregulated in ESCs, IPSCs and ECCs including PARP1, CCNE1, CDK6, AURKA, MAD2L1, CCNG1, and CCNB1 which are involved in cell cycle regulation, cellular metabolism and DNA repair and replication. Gene classification analysis also confirmed that the distinguishing feature of EGCs compared to ESCs, ECCs, and IPSCs lies primarily in their genetic contribution to cellular metabolism, cell cycle, and cell adhesion. In contrast, several genes were found upregulated in PGCs which may help distinguish their unipotent state including HBA1, DMRT1, SPANXA1, and EHD2. Together, these findings provide the first glimpse into a unique genomic signature of human germ cells and pluripotent stem cells and provide genes potentially involved in defining different states of germ-line pluripotency.

In Defending Life: A Moral and Legal Case Against Abortion Choice (2007) and an earlier article in this journal, “Defending Abortion Philosophically”(2006), Francis Beckwith argues that fetuses are, from conception, prima facie wrong to kill. His arguments are based on what he calls a “metaphysics of the human person” known as “The Substance View.” I argue that Beckwith’s metaphysics does not support his abortion ethic: Moral, not metaphysical, claims that are part of this Substance View are the foundation of the argument, and Beckwith inadequately defends these moral claims. Thus, Beckwith’s arguments do not provide strong support for what he calls the “pro-life” view of abortion.

Biomedical science in the 20th century was largely a descriptive and reductionist enterprise. The characterization of isolated cellular components produced a series of important discoveries1, culminating in the sequence of the entire human genome.2 Modern science, now armed with the ability to isolate, culture, genetically engineer, and transplant living tissue has begun to address the fundamental questions of life. How does a fertilized egg direct its own assembly into a complex organism? What makes a muscle cell different than a neuron? Why are some drugs safe and efficacious in animals but toxic or ineffective in humans? Why can’t human beings regenerate severed limbs, but salamanders can?

Microcell-mediated chromosome transfer (MMCT) is a technique that has been in use since the 1970s for the fusion of microcells, containing single or a small number of chromosomes, with whole cells, and the subsequent selection of the hybrids. MMCT can be carried out with somatic cells, embryonic carcinoma (EC) or embryonic stem (ES) cell recipients, to study in vitro or in vivo effects of the transferred genetic material. These effects may be unpredictable-do the transferred genes function normally while in the regulatory milieu of the host cell? Will epigenetic effects become apparent, and how will these alter gene expression? What happens to the host cell phenotype? Here, we present a review of MMCT in which we argue that, although this is an old technique, its adaptability and efficiency make it an excellent method for the dissection of gene function and dysfunction in a very wide range of current systems.

Orthotropic liver transplantation is the only established treatment for end-stage liver diseases. Utilization of hepatocyte transplantation and bio-artificial liver devices as alternative therapeutic approaches requires an unlimited source of hepatocytes. Stem cells, especially embryonic stem cells, possessing the ability to produce functional hepatocytes for clinical applications and drug development, may provide the answer to this problem. New discoveries in the mechanisms of liver development and the emergence of induced pluripotent stem cells in 2006 have provided novel insights into hepatocyte differentiation and the use of stem cells for therapeutic applications. This review is aimed towards providing scientists and physicians with the latest advancements in this rapidly progressing field.

Human embryonic stem (ES) cells are known to derive from the inner cell mass of blastocyst. Although the embryos of other developmental stages have also been used as a source for ES cells in animal models, the feasibility of obtaining ES cell lines from human morula is not known, despite being an obvious source available through assisted reproduction and preimplantation genetic diagnosis programmes. This study describes an original technique for derivation of ES cells from human morula, which enabled the establishment of eight morula-derived ES cell lines. These ES cell lines were shown to have no morphological differences from the ES cells derived from blastocysts, and expressed the same ES cell specific markers, including Oct-4, tumour-resistance antigens TRA-2-39, stage-specific embryonic antigens SSEA-3 and SSEA-4, and high molecular weight glycoproteins TRA-1-60 and TRA-1-81, detected in the same colony of morula-derived ES cells showing specific alkaline phosphatase expression. No differences were observed in these marker expressions in the morula-derived ES cells cultured in the feeder layer free medium. Similar to ES cell originating from blastocyst, the morula-derived ES cells were shown to spontaneously differentiate in vitro into a variety of cell types, including the neuron-like and contracting primitive cardiocytelike cells.

Human stem cells have the potential of self-replication and differentiation, and under certain conditions, are capable of growing into various body parts contributed to multiple functions. Since their discovery in 1945, human stem cells have been widely adapted among cell therapy-centered medical research, treatment, drug safety testing and other applied development.
Ethical controversies are involved with partial sources of the gathered human embryonic cells because the embryonic life would be sacrificed during the process. Although other ways of their acquisition do exist, due to higher success rate of their application within medical research development or application, human embryonic cells have continued to be used by many medical technologies in research. Therefore it has triggered a controversy of bioethical issues under the medical research and application field.
From the perspective of Buddhist doctrine, the embryos are “human-like”. The deprivation of embryos’ lives is nothing different from convicting the crime of homicide. Rooting in a belief in life protection, the thesis is opposed to the concept which determines the right to life of a fetus should be granted only when it passes through the birth canal. There is still room for efforts toward giving more respect to an embryo with 23 pairs of chromosomes, which could eventually develop into an individual.
From the technology-centered perspective, medical research can make great progress to improve the quality of human lives under the prerequisite that no embryo would be harmed. Consideration and respect should as well be paid to embryos’ rights to be as dignified as human lives. In the future, biotechnology experiments in medical research must put a serious focus on this subject.
生命倫理學（bioethics）主要探討生命科學領域中常見的各種道德問題（包括醫病關係、安樂死、墮胎、生殖醫學、人體與動物實驗、防疫與公共衛生等議題），是一門集合醫學、哲學、法學、宗教、社會學、心理學、人類學等多種專業領域的倫理學研究。現今各國對人類胚胎的道德地位雖爭議不斷，但人類胚胎仍被合法化或默許地使用於醫藥臨床實驗。現今臺灣醫療特別法及《民法》等公共領域規範中，人類胚胎相關法規立法基準歧異矛盾，且有將之客體化為「物」的現象。有鑑於我國法律對人類胚胎生命的物化漠視，本文藉儒家仁愛恕道的推擴與佛教戒律保護胚胎「似人」地位，尊重人類胚胎生命的思考，期提供我國未來相關法規對此新時代議題未來進行修法時的參考。

Human pluripotent stem cells comprise induced pluripotent and embryonic stem cells, which have tremendous potential for biological and therapeutic applications. The development of efficient technologies for the targeted genome alteration of stem cells in disease models is a prerequisite for utilizing stem cells to their full potential. Genome editing of stem cells is possible with the help of synthetic nucleases that facilitate site-specific modification of a gene of interest. Recent advances in genome editing techniques have improved the efficiency and speed of the development of stem cells for human disease models. Zinc finger nucleases, transcription acti-vator-like effector nucleases, and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system are powerful tools for editing DNA at specific loci. Here, we discuss recent technological advances in genome editing with site-specific nucleases in human stem cells. Keywords Induced pluripotent stem cells Á Embryonic stem cells Á Zinc finger nucleases Á Transcription activator-like effector nucleases Á Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated system

They had overcome the obstacle of using human embryonic stem cells, but that even so, a potential ethical difficulty remained with the possibility of producing organs in experimental animals. It seems a little excessive that, in less than two months, we have dedicated three reports to the latest studies by Juan Carlos Izpisúa and his group. Nonetheless, we believe that the importance of his work merits this level of interest. In our first report, we referred to a study published in Nature, which describes — among other breakthroughs — the production of human-animal chimeras in order to generate quasi-human organs for use in transplantation. In the report, we mentioned the ethical difficulties evident in the study as a result of the use of human embryonic stem cells.

"We argue in this essay that (1) the embryo is an irredeemably
ambiguous entity and its ambiguity casts serious doubt on the arguments claiming its full protection or, at least, protection against its use as a means for stem cell research, (2) those who claim the embryo should be protected as ‘‘one of us’’ are committed to a position even they do not uphold in their practices, (3) views that defend the protection of the embryo in virtue of its potentiality to become a person fail, and (4) the embryo does not have any rights or interests to be protected. Given that many are willing to treat the embryo as a means in other practices, and that human embryonic stem cell (hESC) research holds great potential to benefit many people, one cannot but conclude that hESC research is permissible and, because of its immense promise for alleviating human suffering,
even obligatory."

Background: Induced pluripotent stem (iPS) cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming, which uses a defined set of transcription factors, iPS cells represent important sources of patient-specific cells for clinical applications. However, before these cells can be used in therapeutic designs, it is essential to understand their genetic stability.

Embryonic stem cells are currently derived from the inner cell mass of human blastocysts, generated from spare embryos donated for research. To overcome ethical concerns raised by destruction of the embryo, two groups of workers have attempted to derive these cells from isolated blastomeres of 8- to 10-cell stage embryos using the embryo biopsy method akin to that used in preimplantation diagnosis. This paper briefly discusses these two techniques in relation to the routine derivation of stem cells from blastocysts. Some embryological aspects of using the inner cell mass of blastocysts in preference to early embryonic cells are presented. The paper also considers some pitfalls in therapeutic cloning, especially in non-human primates, since legislation to allow this procedure for stem cell research is currently being passed in Australia.

Le 18 octobre 2011, la Cour de Justice de l’Union Européenne (CJUE) a rendu un arrêt important en matière de protection de l’embryon humain : l’arrêt Brüstle/Greenpeace eV,  C-34/10. En effet, dans cet arrêt, les juges de Luxembourg n’ont pas hésité, au nom du respect dû à la dignité humaine, à définir objectivement la notion d’embryon humain et à exclure de la brevetabilité tout procédé qui, en utilisant le prélèvement de cellules souches obtenues à partir d’un embryon humain, entraînerait la destruction de l’embryon.

This dissertation uses the methods of interpretive social science to explore the multidimensional nature of the stem cell controversy, its competing epistemologies, and types of resolution and policy closure that have been sought in the United States and the European Union. It provides a comparative perspective on the social dynamics of public involvement in stem cell research and evaluates efforts by governments and bioethics advisory bodies to integrate dialogue and deliberation in science policy and decision making. The analysis highlights the agenda-setting and framing roles of the print and electronic news media in the public discourse over stem cells and human cloning, including their ability to validate conflicting knowledge claims about stem cell science and frame uncertainty about its clinical promise. I argue that stem cell policy debates are deeply embedded in particular socio-political and cultural contexts, and therefore regulatory responses to the societal challenges arising from this biomedical innovation have largely been shaped by non-epistemic factors (considerations external to science and its epistemologies). In the US, the issue of human embryonic stem cell research was right from the outset framed in terms of the contentious politics of abortion, became caught up in America’s culture wars, and the funding policy debate revived salient political themes of earlier controversies over abortion and fetal transplantation research. By contrast, efforts by EU policymakers to develop a framework for the ethical governance of stem cell technologies and their applications in regenerative medicine were intertwined with fundamental questions of EU federalism, common European cultural values, and the traditional consensus-oriented politics. I claim that in both cases the moral and policy dilemma was brought to a conclusion by non-epistemic procedural closure. By sealing off the debate through legislative and administrative procedures, policymakers have failed to achieve a morally justifiable resolution of the issues central to the stem cell controversy either through the method of consensus closure or on the basis of epistemic (knowledge-based) factors.

Conventional generation of stem cells from human blastocysts produces a developmentally advanced, or primed, stage of pluripotency. In vitro resetting to a more naive phenotype has been reported. However, whether the reset culture conditions of selective kinase inhibition can enable capture of naive epiblast cells directly from the embryo has not been determined. Here, we show that in these specific conditions individual inner cell mass cells grow into colonies that may then be expanded over multiple passages while retaining a diploid karyotype and naive properties. The cells express hallmark naive pluripotency factors and additionally display features of mitochondrial respiration, global gene expression, and genome-wide hypomethylation distinct from primed cells. They transition through primed pluripotency into somatic lineage differentiation. Collectively these attributes suggest classification as human naive embryonic stem cells. Human counterparts of canonical mouse embryonic stem cells would argue for conservation in the phased progression of pluripotency in mammals.

Although human embryonic stem cells (hESC) have been shown to present a stable diploid karyotype 1 , many studies have reported that depending on culture conditions they become prone to acquire chromosomal anomalies such as addition of whole or parts of chromosomes. Indeed, during long-term culture, karyotypic alterations are observed when enzymatic or chemical dissociation are used 2,3,4 , while manual dissection of colonies for passaging retains a stable karyotype 5 . Besides, changes in the environment such as the removal of feeder cells also seem to compromise the genetic integrity of hESC 3,6 . Once chromosomal alterations could affect cellular physiology, the characterization of the genetic integrity of hESC in vitro is crucial considering hESC as an essential tool in embryogenesis studies and drug testing. Furthermore, for future therapeutic purposes chromosomal changes are a real concern as it is frequently associated to carcinogenesis.