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Pluripotent Embryonic Stem Cells (pluripotent + embryonic_stem_cell)

Distribution by Scientific Domains
Life Sciences60%
Medical Sciences40%

Selected Abstracts

Engineering tissues, organs and cells

JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE, Issue 2 2007
Anthony Atala
Abstract Patients suffering from diseased and injured organs may be treated with transplanted organs; however, there is a severe shortage of donor organs that is worsening yearly, given the ageing population. In the field of regenerative medicine and tissue engineering, scientists apply the principles of cell transplantation, materials science and bioengineering to construct biological substitutes that will restore and maintain normal function in diseased and injured tissues. Therapeutic cloning, where the nucleus from a donor cell is transferred into an enucleated oocyte in order to extract pluripotent embryonic stem cells, offers a potentially limitless source of cells for tissue engineering applications. The stem cell field is also advancing rapidly, opening new options for therapy, including the use of amniotic and placental fetal stem cells. This review covers recent advances that have occurred in regenerative medicine and describes applications of these technologies using chemical compounds that may offer novel therapies for patients with end-stage organ failure. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Improved cardiac function in infarcted mice after treatment with pluripotent embryonic stem cells

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 11 2006
Timothy J. Nelson
Abstract Because pluripotent embryonic stem cells (ESCs) are able to differentiate into any tissue, they are attractive agents for tissue regeneration. Although improvement of cardiac function has been observed after transplantation of pluripotent ESCs, the extent to which these effects reflect ESC-mediated remuscularization, revascularization, or paracrine mechanisms is unknown. Moreover, because ESCs may generate teratomas, the ability to predict the outcome of cellular differentiation, especially when transplanting pluripotent ESCs, is essential; conversely, a requirement to use predifferentiated ESCs would limit their application to highly characterized subsets that are available in limited numbers. In the experiments reported here, we transplanted low numbers of two murine ESC lines, respectively engineered to express a ,-galactosidase gene from either a constitutive (elongation factor) or a cardiac-specific (,-myosin heavy chain) promoter, into infarcted mouse myocardium. Although ESC-derived tumors formed within the pericardial space in 21% of injected hearts, lacZ histochemistry revealed that engraftment of ESC was restricted to the ischemic myocardium. Echocardiographic monitoring of ESC-injected hearts that did not form tumors revealed functional improvements by 4 weeks postinfarction, including significant increases in ejection fraction, circumferential fiber shortening velocity, and peak mitral blood flow velocity. These experiments indicate that the infarcted myocardial environment can support engraftment and cardiomyogenic differentiation of pluripotent ESCs, concomitant with partial functional recovery. Anat Rec Part A, 288A:1216,1224, 2006. © 2006 Wiley-Liss, Inc. [source]

Stem cells and diabetes treatment,

APMIS, Issue 11-12 2005
OLE DRAGSBÆK MADSEN
Diabetes mellitus types 1 and 2 are characterized by absolute versus relative lack of insulin-producing , cells, respectively. Reconstitution of a functional ,-cell mass by cell therapy , using organ donor islets of Langerhans , has been demonstrated to restore euglycaemia in the absence of insulin treatment. This remarkable achievement has stimulated the search for appropriate stem cell sources from which adequate expansion and maturation of therapeutic , cells can be achieved. This recent activity is reviewed and presented with particular focus on directed differentiation from pluripotent embryonic stem cells (versus other stem/progenitor cell sources) based on knowledge from pancreatic ,-cell development and the parallel approach to controlling endogenous ,-cell neogenesis. [source]

Epigenetic "bivalently marked" process of cancer stem cell-driven tumorigenesis

BIOESSAYS, Issue 9 2007
Curt Balch
Silencing of tumor suppressor genes (TSGs), by DNA methylation, is well known in adult cancers. However, based on the "stem cell" theory of tumorigenesis, the early epigenetic events arising in malignant precursors remain unknown. A recent report1 demonstrates that, while pluripotent embryonic stem cells lack DNA methylation and possess a "bivalent" pattern of activating and repressive histone marks in numerous TSGs, analogous multipotent malignant cells derived from germ cell tumors (embryonic carcinoma cells) gain additional silencing modifications to those same genes. These results suggest a possible mechanism by which aberrant differentiation, mediated by histone and DNA methylation, instigates tumor progression. BioEssays 29:842,845, 2007. © 2007 Wiley Periodicals, Inc. [source]

Three-dimensional culture systems for the expansion of pluripotent embryonic stem cells

BIOTECHNOLOGY & BIOENGINEERING, Issue 4 2010
Michael P. Storm
Abstract Mouse embryonic stem cell (ESC) lines, and more recently human ESC lines, have become valuable tools for studying early mammalian development. Increasing interest in ESCs and their differentiated progeny in drug discovery and as potential therapeutic agents has highlighted the fact that current two-dimensional (2D) static culturing techniques are inadequate for large-scale production. The culture of mammalian cells in three-dimensional (3D) agitated systems has been shown to overcome many of the restrictions of 2D and is therefore likely to be effective for ESC proliferation. Using murine ESCs as our initial model, we investigated the effectiveness of different 3D culture environments for the expansion of pluripotent ESCs. Solohill Collagen, Solohill FACT, and Cultispher-S microcarriers were employed and used in conjunction with stirred bioreactors. Initial seeding parameters, including cell number and agitation conditions, were found to be critical in promoting attachment to microcarriers and minimizing the size of aggregates formed. While all microcarriers supported the growth of undifferentiated mESCs, Cultispher-S out-performed the Solohill microcarriers. When cultured for successive passages on Cultispher-S microcarriers, mESCs maintained their pluripotency, demonstrated by self-renewal, expression of pluripotency markers and the ability to undergo multi-lineage differentiation. When these optimized conditions were applied to unweaned human ESCs, Cultispher-S microcarriers supported the growth of hESCs that retained expression of pluripotency markers including SSEA4, Tra-1,60, NANOG, and OCT-4. Our study highlights the importance of optimization of initial seeding parameters and provides proof-of-concept data demonstrating the utility of microcarriers and bioreactors for the expansion of hESCs. Biotechnol. Bioeng. 2010;107:683,695. © 2010 Wiley Periodicals, Inc. [source]