395,917 research outputs found
Institutional imaginaries of publics in stem cell banking: The cases of the UK and Spain
The UK and Spanish Stem Cell Banks hold politically controversial-but potentially therapeutically beneficial-human embryonic stem cells for distribution to research laboratories globally. The UK bank was the first of its type in the world, opening in 2004, and the Spanish bank used it as a role model in its own development. Both banks structure their operations in response to how their staffs imagine the publics in their nation make trust judgements about their work. Differences between the workings of each bank can be traced to differences in the collective imaginings operating at each bank-termed 'institutional imaginaries'-about how publics think. The UK bank sustains an imaginary in which distance lends legitimacy and disengagement signifies correct moral practice. It conjures a public that values a steady, safe and reliable institution-free from potential conflict of interest-about which the less news the better. This stands in contrast to the Spanish bank that conjures a public that retains an interest in legitimate, ethical guardianship of stem cell material, but which is less worried about conflict of interest in attaining this. Instead, for the Spanish institution, engagement with science and the media through the projection of the bank as cutting edge is deemed crucial for maintaining public support. © 2013 Copyright Process Press.The support of the Economic and Social Research Council (ESRC) is gratefully acknowledged. This work was undertaken as part of the research programme of the
ESRC Genomics Network at the Centre for Economic and Social Aspects of
Genomics (Cesagen), Cardiff School of Social Sciences, Cardiff University, UK
Diverse Perspectives: Considerations About Embryonic Stem Cell Research
This is a single report.Since the initial isolation of human embryonic stem cells in 1998 (Thomson et al. 1998), important developments in research have offered the promise of valuable therapeutic breakthroughs while continuing to raise significant social, ethical, legal and policy challenges. Among the interests of the Indiana University Center for Bioethics (IUCB) is a desire to engage issues of this kind, and in so doing, to provide a resource to the IU community, to Indiana, and to the entire country. The topic of stem cell research was, therefore, an appropriate one for discussion at the Center. In January 2002, the IUCB created a Stem Cell Study Group (SCSG). Our primary goal was to provide a forum for informed public discussion of the issues by making use of the considerable local scientific, legal and ethical expertise. In other words, we wanted primarily to educate ourselves about these issues. Our secondary goal was to identify and describe those points on which agreement could be achieved, as well as those issues on which agreement proved difficult if not impossible. This paper summarizes our efforts to meet both of these goals
Why regenerative stem cell medicine progresses slower than expected
Stem cell research has been acclaimed to revolutionize the future of medicine, and to offer new treatments for previously incurable diseases. Despite years of research, however, the therapeutic potential of stem cell research has not yet been fully realized. By June 2014, the US Food and Drug Administration had approved only five stem cell-based medicinal products, all of which cord blood derived hematopoietic stem cell products for the cure of blood and immunological diseases. Anticipated treatments for cancer, neurodegenerative disorders, gastroenterological, myocardial, and other diseases are still far from routine applications. What are the reasons for the slow progress in the stem cell field, and the mismatch between public expectations and actual achievements
25 years of epidermal stem cell research.
This is a chronicle of concepts in the field of epidermal stem cell biology and a historic look at their development over time. The past 25 years have seen the evolution of epidermal stem cell science, from first fundamental studies to a sophisticated science. The study of epithelial stem cell biology was aided by the ability to visualize the distribution of stem cells and their progeny through lineage analysis studies. The excellent progress we have made in understanding epidermal stem cell biology is discussed in this article. The challenges we still face in understanding epidermal stem cells include defining molecular markers for stem and progenitor sub-populations, determining the locations and contributions of the different stem cell niches, and mapping regulatory pathways of epidermal stem cell proliferation and differentiation. However, our rapidly evolving understanding of epidermal stem cells has many potential uses that promise to translate into improved patient therapy
The Stat3-Fam3a axis promotes muscle stem cell myogenic lineage progression by inducing mitochondrial respiration.
Metabolic reprogramming is an active regulator of stem cell fate choices, and successful stem cell differentiation in different compartments requires the induction of oxidative phosphorylation. However, the mechanisms that promote mitochondrial respiration during stem cell differentiation are poorly understood. Here we demonstrate that Stat3 promotes muscle stem cell myogenic lineage progression by stimulating mitochondrial respiration in mice. We identify Fam3a, a cytokine-like protein, as a major Stat3 downstream effector in muscle stem cells. We demonstrate that Fam3a is required for muscle stem cell commitment and skeletal muscle development. We show that myogenic cells secrete Fam3a, and exposure of Stat3-ablated muscle stem cells to recombinant Fam3a in vitro and in vivo rescues their defects in mitochondrial respiration and myogenic commitment. Together, these findings indicate that Fam3a is a Stat3-regulated secreted factor that promotes muscle stem cell oxidative metabolism and differentiation, and suggests that Fam3a is a potential tool to modulate cell fate choices
A Critical Examination of the Question of Personhood in Stem Cell Research
Stem cell research programme has been celebrated world over as the most promising medical research in the 21st century. However, the method of stem cell research involves the use and unavoidable destruction of human embryo. As a result of this, many theologians, scholars and analysts have condemned the research programme. Their argument is that the embryo use in stem cell research is human person; hence it is immoral. This paper therefore aims at analyzing and examining the issue in order to establish the veracity or otherwise of the moral argument articulated against stem cell research
Designing signaling environments to steer transcriptional diversity in neural progenitor cell populations
Stem cell populations within developing embryos are diverse, composed of many different subpopulations of cells with varying developmental potential. The structure of stem cell populations in cell culture remains poorly understood and presents a barrier to differentiating stem cells for therapeutic applications. In this paper we develop a framework for controlling the architecture of stem cell populations in cell culture using high-throughput single cell mRNA-seq and computational analysis. We find that the transcriptional diversity of neural stem cell populations collapses in cell culture. Cell populations are depleted of committed neuron progenitor cells and become dominated by a single pre-astrocytic cell population. By analyzing the response of neural stem cell populations to forty distinct signaling conditions, we demonstrate that signaling environments can restructure cell populations by modulating the relative abundance of pre-astrocyte and pre-neuron subpopulations according to a simple linear code. One specific combination of BMP4, EGF, and FGF2 ligands switches the default population balance such that 70% of cells correspond to the committed neurons. Our work demonstrates that single-cell RNA-seq can be applied to modulate the diversity of in vitro stem cell populations providing a new strategy for population-level stem cell control
Effect of Dedifferentiation on Time to Mutation Acquisition in Stem Cell-Driven Cancers
Accumulating evidence suggests that many tumors have a hierarchical
organization, with the bulk of the tumor composed of relatively differentiated
short-lived progenitor cells that are maintained by a small population of
undifferentiated long-lived cancer stem cells. It is unclear, however, whether
cancer stem cells originate from normal stem cells or from dedifferentiated
progenitor cells. To address this, we mathematically modeled the effect of
dedifferentiation on carcinogenesis. We considered a hybrid
stochastic-deterministic model of mutation accumulation in both stem cells and
progenitors, including dedifferentiation of progenitor cells to a stem
cell-like state. We performed exact computer simulations of the emergence of
tumor subpopulations with two mutations, and we derived semi-analytical
estimates for the waiting time distribution to fixation. Our results suggest
that dedifferentiation may play an important role in carcinogenesis, depending
on how stem cell homeostasis is maintained. If the stem cell population size is
held strictly constant (due to all divisions being asymmetric), we found that
dedifferentiation acts like a positive selective force in the stem cell
population and thus speeds carcinogenesis. If the stem cell population size is
allowed to vary stochastically with density-dependent reproduction rates
(allowing both symmetric and asymmetric divisions), we found that
dedifferentiation beyond a critical threshold leads to exponential growth of
the stem cell population. Thus, dedifferentiation may play a crucial role, the
common modeling assumption of constant stem cell population size may not be
adequate, and further progress in understanding carcinogenesis demands a more
detailed mechanistic understanding of stem cell homeostasis
Theurapeutic Effectiveness of Rat Bone Marrow Stem Cells in Poly Cystic Ovary Syndrome Mice Model on Folliculogenesis, TGF-β, GDF-9 Expression, and Estrogen, TNF- and Androgen Levels
Objectives: to identify therapeutic effectiveness of Rat Bone Marrow stem cell in PCOS rats model on folliculogenesis, TGF-beta and GDF-9 expression and on estrogen, TNF-a and androgen levels.Material and Methods: this study is a laboratory experimental research with using animal testing. PCOS was induced by the administration of testosterone propionate hormone into 30 mice. The subjects of this study are divided into 2 groups: stem cell group and control group. The mice were injected with testosterone then vaginal swab was performed to determine the mice cycle. After determining mice in anestrous cycle, stem cell was injected. TNF-a was measured with immunohistochemistry and androgen was examined using ELISA. The data was measured by student t-test.Result: The average number of TNF-a expression in control group was lower than stem cell group (5.35 vs 2.34; p= 0.0026). The average androgen level for stem cell group was lower than mean for control group (2.31 vs 0.40; p= 0.0026).Conclusion: In this study of polycystic model mice, stem cell decreased the expression of TNF-a and androgen leve
Stem cell mechanobiology
Stem cells are undifferentiated cells that are capable of proliferation, self-maintenance and differentiation towards specific cell phenotypes. These processes are controlled by a variety of cues including physicochemical factors associated with the specific mechanical environment in which the cells reside. The control of stem cell biology through mechanical factors remains poorly understood and is the focus of the developing field of mechanobiology. This review provides an insight into the current knowledge of the role of mechanical forces in the induction of differentiation of stem cells. While the details associated with individual studies are complex and typically associated with the stem cell type studied and model system adopted, certain key themes emerge. First, the differentiation process affects the mechanical properties of the cells and of specific subcellular components. Secondly, that stem cells are able to detect and respond to alterations in the stiffness of their surrounding microenvironment via induction of lineage-specific differentiation. Finally, the application of external mechanical forces to stem cells, transduced through a variety of mechanisms, can initiate and drive differentiation processes. The coalescence of these three key concepts permit the introduction of a new theory for the maintenance of stem cells and alternatively their differentiation via the concept of a stem cell 'mechano-niche', defined as a specific combination of cell mechanical properties, extracellular matrix stiffness and external mechanical cues conducive to the maintenance of the stem cell population.<br/
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