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  • French A, Bravery C, Smith J, Chandra A, Archibald P, Gold JD, Artzi N, Kim HW, Barker RW, Meissner A, Wu JC, Knowles JC, Williams D, García-Cardeña G, Sipp D, Oh S, Loring JF, Rao MS, Reeve B, Wall I, Carr AJ, Bure K, Stacey G, Karp JM, Snyder EY, Brindley DA. Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards. Stem Cells Transl Med. 2015 Mar;4(3):217-23. PubMed: 25650438. Categories: RepleniSENS

    Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards.

    Stem Cells Transl Med. 2015 Mar;4(3):217-23.

    Enabling consistency in pluripotent stem cell-derived products for research and development and clinical applications through material standards.

    French A, Bravery C, Smith J, Chandra A, Archibald P, Gold JD, Artzi N, Kim HW, Barker RW, Meissner A, Wu JC, Knowles JC, Williams D, García-Cardeña G, Sipp D, Oh S, Loring JF, Rao MS, Reeve B, Wall I, Carr AJ, Bure K, Stacey G, Karp JM, Snyder EY, Brindley DA.

    Abstract

    Abstract:

    There is a need for physical standards (reference materials) to ensure both reproducibility and consistency in the production of somatic cell types from human pluripotent stem cell (hPSC) sources. We have outlined the need for reference materials (RMs) in relation to the unique properties and concerns surrounding hPSC-derived products and suggest in-house approaches to RM generation relevant to basic research, drug screening, and therapeutic applications. hPSCs have an unparalleled potential as a source of somatic cells for drug screening, disease modeling, and therapeutic application. Undefined variation and product variability after differentiation to the lineage or cell type of interest impede efficient translation and can obscure the evaluation of clinical safety and efficacy. Moreover, in the absence of a consistent population, data generated from in vitro studies could be unreliable and irreproducible. Efforts to devise approaches and tools that facilitate improved consistency of hPSC-derived products, both as development tools and therapeutic products, will aid translation. Standards exist in both written and physical form; however, because many unknown factors persist in the field, premature written standards could inhibit rather than promote innovation and translation. We focused on the derivation of physical standard RMs. We outline the need for RMs and assess the approaches to in-house RM generation for hPSC-derived products, a critical tool for the analysis and control of product variation that can be applied by researchers and developers. We then explore potential routes for the generation of RMs, including both cellular and noncellular materials and novel methods that might provide valuable tools to measure and account for variation. Multiparametric techniques to identify "signatures" for therapeutically relevant cell types, such as neurons and cardiomyocytes that can be derived from hPSCs, would be of significant utility, although physical RMs will be required for clinical purposes.

  • Silva M, Daheron L, Hurley H, Bure K, Barker R, Carr AJ, Williams D, Kim HW, French A, Coffey PJ, Cooper-White JJ, Reeve B, Rao M, Snyder EY, Ng KS, Mead BE, Smith JA, Karp JM, Brindley DA, Wall I. Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies. Cell Stem Cell. 2015 Jan 8;16(1):13-7. PubMed: 25575079. Categories: RepleniSENS

    Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies.

    Cell Stem Cell. 2015 Jan 8;16(1):13-7.

    Generating iPSCs: Translating Cell Reprogramming Science into Scalable and Robust Biomanufacturing Strategies.

    Silva M, Daheron L, Hurley H, Bure K, Barker R, Carr AJ, Williams D, Kim HW, French A, Coffey PJ, Cooper-White JJ, Reeve B, Rao M, Snyder EY, Ng KS, Mead BE, Smith JA, Karp JM, Brindley DA, Wall I.

    Abstract

    Abstract:

    Induced pluripotent stem cells (iPSCs) have the potential to transform drug discovery and healthcare in the 21(st) century. However, successful commercialization will require standardized manufacturing platforms. Here we highlight the need to define standardized practices for iPSC generation and processing and discuss current challenges to the robust manufacture of iPSC products.

  • Boura JS, Vance M, Yin W, Madeira C, Lobato da Silva C, Porada CD, Almeida-Porada G. Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells. Mol Ther Methods Clin Dev. 2014 Sep;2014(1). pii: 14041. PubMed: 25279386. Categories: OncoSENS, RepleniSENS

    Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells.

    Mol Ther Methods Clin Dev. 2014 Sep;2014(1). pii: 14041.

    Evaluation of gene delivery strategies to efficiently overexpress functional HLA-G on human bone marrow stromal cells.

    Boura JS, Vance M, Yin W, Madeira C, Lobato da Silva C, Porada CD, Almeida-Porada G.

    Abstract

    Abstract:

    Mesenchymal stromal cells (MSC) constitutively express low levels of human leukocyte antigen-G (HLA-G), which has been shown to contribute to their immunomodulatory and anti-inflammatory properties. Here, we hypothesized that overexpression of HLA-G on bone marrow-derived MSC would improve their immunomodulatory function, thus increasing their therapeutic potential. Therefore, we investigated which gene transfer system is best suited for delivering this molecule while maintaining its immuno-modulatory effects. We performed a side-by-side comparison between three nonviral plasmid-based platforms (pmax-HLA-G1; MC-HLA-G1; pEP-HLA-G1) and a viral system (Lv-HLA-G1) using gene transfer parameters that yielded similar levels of HLA-G1-expressing MSC. Natural killer (NK) cell-mediated lysis assays and T cell proliferation assays showed that MSC modified with the HLA-G1 expressing viral vector had significantly lower susceptibility to NK-lysis and significantly reduced T cell proliferation when compared to nonmodified cells or MSC modified with plasmid. We also show that, in plasmid-modified MSC, an increase in Toll-like receptor (TLR)9 expression is the mechanism responsible for the abrogation of HLA-G1's immunomodulatory effect. Although MSC can be efficiently modified to overexpress HLA-G1 using viral and nonviral strategies, only viral-based delivery of HLA-G1 is suitable for improvement of MSC's immunomodulatory properties.

  • Elabd C, Cousin W, Upadhyayula P, Chen RY, Chooljian MS, Li J, Kung S, Jiang KP, Conboy IM. Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration. Nat Commun. 2014 Jun 10;5:4082. doi: 10.1038/ncomms5082. PubMed: 24915299. Categories: RepleniSENS

    Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.

    Nat Commun. 2014 Jun 10;5:4082. doi: 10.1038/ncomms5082.

    Oxytocin is an age-specific circulating hormone that is necessary for muscle maintenance and regeneration.

    Elabd C, Cousin W, Upadhyayula P, Chen RY, Chooljian MS, Li J, Kung S, Jiang KP, Conboy IM.

    Abstract

    Abstract:

    The regenerative capacity of skeletal muscle declines with age. Previous studies suggest that this process can be reversed by exposure to young circulation; however, systemic age-specific factors responsible for this phenomenon are largely unknown. Here we report that oxytocin-a hormone best known for its role in lactation, parturition and social behaviours-is required for proper muscle tissue regeneration and homeostasis, and that plasma levels of oxytocin decline with age. Inhibition of oxytocin signalling in young animals reduces muscle regeneration, whereas systemic administration of oxytocin rapidly improves muscle regeneration by enhancing aged muscle stem cell activation/proliferation through activation of the MAPK/ERK signalling pathway. We further show that the genetic lack of oxytocin does not cause a developmental defect in muscle but instead leads to premature sarcopenia. Considering that oxytocin is an FDA-approved drug, this work reveals a potential novel and safe way to combat or prevent skeletal muscle ageing.

  • Chen Y, Ma X, Zhang M, Wang X, Wang C, Wang H, Guo P, Yuan W, Rudolph KL, Zhan Q, Ju Z. Gadd45a regulates hematopoietic stem cell stress responses in mice. Blood. 2014 Feb 6;123(6):851-62. doi: 10.1182/blood-2013-05-504084. PubMed: 24371210. Categories: RepleniSENS

    Gadd45a regulates hematopoietic stem cell stress responses in mice.

    Blood. 2014 Feb 6;123(6):851-62. doi: 10.1182/blood-2013-05-504084.

    Gadd45a regulates hematopoietic stem cell stress responses in mice.

    Chen Y, Ma X, Zhang M, Wang X, Wang C, Wang H, Guo P, Yuan W, Rudolph KL, Zhan Q, Ju Z.

    Abstract

    Abstract:

    Gadd45a has been involved in DNA damage response and in many malignancies, including leukemia. However, the function of Gadd45a in hematopoietic stem cells (HSCs) remains unknown. Here, we reported that Gadd45a-deficient (Gadd45a(-/-)) mice showed a normal hematologic phenotype under homeostatic conditions. However, following 5-fluorouracil treatment, Gadd45a(-/-) HSCs exhibited a faster recovery, associated with an increase in the proliferation rate. Interestingly, young Gadd45a(-/-) HSCs showed enhanced reconstitution ability in serial transplantation. Following ionizing radiation (IR), young Gadd45a(-/-) HSCs exhibited an increased resistance to IR-induced DNA damage, associated with a decrease in the apoptosis rate and delayed DNA repair. The significantly higher level of DNA damage in Gadd45a(-/-) HSCs ultimately promoted B-cell leukemia in further transplanted recipient mice. In old mice, Gadd45a(-/-) HSCs were functionally equal to wild-type HSCs but exhibited more DNA damage accumulation and increased sensitivity to IR than wild-type HSCs. In conclusion, Gadd45a plays a significant role in HSC stress responses. Gadd45a deficiency leads to DNA damage accumulation and impairment in apoptosis after exposure to IR, which increases the susceptibility of leukemogenesis.

  • Rohani L, Johnson AA, Arnold A, Stolzing A. The aging signature: a hallmark of induced pluripotent stem cells? Aging Cell 2014;13(1):2-7. PubMed: 24256351. Categories: RepleniSENS

    The aging signature: a hallmark of induced pluripotent stem cells?

    Aging Cell 2014;13(1):2-7.

    The aging signature: a hallmark of induced pluripotent stem cells?

    Rohani L, Johnson AA, Arnold A, Stolzing A.

    Abstract

    Abstract:

    The discovery that somatic cells can be induced into a pluripotent state by the expression of reprogramming factors has enormous potential for therapeutics and human disease modeling. With regard to aging and rejuvenation, the reprogramming process resets an aged, somatic cell to a more youthful state, elongating telomeres, rearranging the mitochondrial network, reducing oxidative stress, restoring pluripotency, and making numerous other alterations. The extent to which induced pluripotent stem cell (iPSC)s mime embryonic stem cells is controversial, however, as iPSCs have been shown to harbor an epigenetic memory characteristic of their tissue of origin which may impact their differentiation potential. Furthermore, there are contentious data regarding the extent to which telomeres are elongated, telomerase activity is reconstituted, and mitochondria are reorganized in iPSCs. Although several groups have reported that reprogramming efficiency declines with age and is inhibited by genes upregulated with age, others have successfully generated iPSCs from senescent and centenarian cells. Mixed findings have also been published regarding whether somatic cells generated from iPSCs are subject to premature senescence. Defects such as these would hinder the clinical application of iPSCs, and as such, more comprehensive testing of iPSCs and their potential aging signature should be conducted.

  • Chen Y, Yang R, Guo P, Ju Z. Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice. Protein Cell. 2014 Jan;5(1):80-9. doi: 10.1007/s13238-013-0017-9. PubMed: 24474198. Categories: RepleniSENS

    Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice.

    Protein Cell. 2014 Jan;5(1):80-9. doi: 10.1007/s13238-013-0017-9.

    Gadd45a deletion aggravates hematopoietic stem cell dysfunction in ATM-deficient mice.

    Chen Y, Yang R, Guo P, Ju Z.

    Abstract

    Abstract:

    Ataxia telangiectasia mutated (ATM) kinase plays an essential role in the maintenance of genomic stability. ATM-deficient (ATM(-/-)) mice exhibit hematopoietic stem cell (HSC) dysfunction and a high incidence of lymphoma. Gadd45a controls cell cycle arrest, apoptosis and DNA repair, and is involved in the ATM-p53 mediated DNA damage response. However, the role of Gadd45a in regulating the functionality of ATM(-/-) HSCs is unknown. Here we report that Gadd45a deletion did not rescue the defects of T-cells and B-cells development in ATM(-/-) mice. Instead, ATM and Gadd45a double knockout (ATM(-/-) Gadd45a(-/-)) HSCs exhibited an aggravated defect in long-term self-renewal capacity compared to ATM(-/-) HSCs in HSC transplantation experiments. Further experiments revealed that the aggravated defect of ATM(-/-) Gadd45a(-/-) HSCs was due to a reduction of cell proliferation, associated with an accumulation of DNA damage and subsequent activation of DNA damage response including an up-regulation of p53-p21 signaling pathway. Additionally, ATM(-/-) Gadd45a(-/-) mice showed an increased incidence of hematopoietic malignancies, as well as an increased rate of metastasis than ATM(-/-) mice. In conclusion, Gadd45a deletion aggravated the DNA damage accumulation, which subsequently resulted in a further impaired self-renewal capacity and an increased malignant transformation in ATM(-/-) HSCs.

  • Zhang J, Yang R, Zhou D, Rudolph KL, Meng A, Ju Z. Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells. Stem Cell Res. 2014 Jan;12(1):250-9. doi: 10.1016/j.scr.2013.11.001. PubMed: 24280419. Categories: RepleniSENS

    Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells.

    Stem Cell Res. 2014 Jan;12(1):250-9. doi: 10.1016/j.scr.2013.11.001.

    Exonuclease 1 is essential for maintaining genomic stability and the proliferative capacity of neural but not hematopoietic stem cells.

    Zhang J, Yang R, Zhou D, Rudolph KL, Meng A, Ju Z.

    Abstract

    Abstract:

    Exonuclease 1 (Exo1) has been implicated in the regulation of DNA damage responses in stem cells with dysfunctional telomeres. However, it is unclear whether Exo1-mediated DNA maintenance pathways play a role in the maintenance of genomic stability and the self-renewal of tissue stem cells in mice with functional telomeres. Here, we analyzed the proliferative capacity of neural stem cells (NSCs) and hematopoietic stem cells (HSCs) from Exo1(-/-) mice. Our study shows that Exo1 deficiency impairs the maintenance of genomic stability and proliferative capacity in NSCs but not HSCs. In line with these results, we detected a decrease in proliferation and an up-regulation of p21 expression levels in Exo1-deficient NSCs but not Exo1-deficient HSCs. Our data provide experimental evidence that Exo1 deficiency has a differential impact on the homeostasis and proliferative capacity of tissue stem cells in the brain and bone marrow, suggesting that different tissue stem cells utilize distinct mechanisms for maintaining their genomic stability. Our current study provides important insight into the role of Exo1-mediated DNA maintenance pathways in the maintenance of genomic stability and the proliferative capacity of tissue stem cells.

  • Wood JA, Colletti E, Mead LE, Ingram D, Porada CD, Zanjani ED, Yoder MC, Almeida-Porada G Distinct contribution of human cord blood-derived endothelial colony forming cells to liver and gut in a fetal sheep model Hepatology. 2012 Sep;56(3):1086-96. doi: 10.1002/hep.25753. PubMed: 22488442. Categories: OncoSENS, RepleniSENS

    Distinct contribution of human cord blood-derived endothelial colony forming cells to liver and gut in a fetal sheep model

    Hepatology. 2012 Sep;56(3):1086-96. doi: 10.1002/hep.25753.

    Distinct contribution of human cord blood-derived endothelial colony forming cells to liver and gut in a fetal sheep model

    Wood JA, Colletti E, Mead LE, Ingram D, Porada CD, Zanjani ED, Yoder MC, Almeida-Porada G

    Abstract

    Abstract:

    Although the vasculogenic potential of circulating and cord blood (CB)-derived endothelial colony-forming cells (ECFC) has been demonstrated in vitro and in vivo, little is known about the inherent biologic ability of these cells to home to different organs and contribute to tissue-specific cell populations. Here we used a fetal sheep model of in utero transplantation to investigate and compare the intrinsic ability of human CB-derived ECFC to migrate to the liver and to the intestine, and to define ECFC's intrinsic ability to integrate and contribute to the cytoarchitecture of these same organs. ECFCs were transplanted by an intraperitoneal or intrahepatic route (IH) into fetal sheep at concentrations ranging from 1.1-2.6 × 10(6) cells/fetus. Recipients were evaluated at 85 days posttransplant for donor (human) cells using flow cytometry and confocal microscopy. We found that, regardless of the route of injection, and despite the IH delivery of ECFC, the overall liver engraftment was low, but a significant percentage of cells were located in the perivascular regions and retained the expression of hallmark endothelial makers. By contrast, ECFC migrated preferentially to the intestinal crypt region and contributed significantly to the myofibroblast population. Furthermore, ECFC expressing CD133 and CD117 lodged in areas where endogenous cells expressed those same phenotypes. CONCLUSION: ECFC inherently constitute a potential source of cells for the treatment of intestinal diseases, but strategies to increase the numbers of ECFC persisting within the hepatic parenchyma are needed in order to enhance ECFC therapeutic potential for this organ.

  • Brindley DA, Davie NL, Sahlman WA, Bonfiglio GA, Culme-Seymour EJ, Reeve BC, Mason C. Promising growth and investment in the cell therapy industry during the first quarter of 2012. Cell Stem Cell. 2012 May 4;10(5):492-6. PubMed: 22560072. Categories: RepleniSENS

    Promising growth and investment in the cell therapy industry during the first quarter of 2012.

    Cell Stem Cell. 2012 May 4;10(5):492-6.

    Promising growth and investment in the cell therapy industry during the first quarter of 2012.

    Brindley DA, Davie NL, Sahlman WA, Bonfiglio GA, Culme-Seymour EJ, Reeve BC, Mason C.

    Abstract

    Abstract:

    In the first quarter of 2012, publicly traded companies in the cell-based therapy industry continued to show promising overall growth. Highlights included $85 million in new capital investment and steady clinical trial progress.

  • Brindley D, Moorthy K, Lee JH, Mason C, Kim HW, Wall I. Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy. J Tissue Eng. 2011;2011:620247. PubMed: 21904661. Categories: RepleniSENS

    Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy.

    J Tissue Eng. 2011;2011:620247.

    Bioprocess forces and their impact on cell behavior: implications for bone regeneration therapy.

    Brindley D, Moorthy K, Lee JH, Mason C, Kim HW, Wall I.

    Abstract

    Abstract:

    Bioprocess forces such as shear stress experienced during routine cell culture are considered to be harmful to cells. However, the impact of physical forces on cell behavior is an area of growing interest within the tissue engineering community, and it is widely acknowledged that mechanical stimulation including shear stress can enhance osteogenic differentiation. This paper considers the effects of bioprocess shear stress on cell responses such as survival and proliferation in several contexts, including suspension-adapted cells used for recombinant protein and monoclonal antibody manufacture, adherent cells for therapy in suspension, and adherent cells attached to their growth substrates. The enhanced osteogenic differentiation that fluid flow shear stress is widely found to induce is discussed, along with the tissue engineering of mineralized tissue using perfusion bioreactors. Recent evidence that bioprocess forces produced during capillary transfer or pipetting of cell suspensions can enhance osteogenic responses is also discussed.

  • Rodier F, Campisi J. Four faces of cellular senescence. J Cell Biol. 2011 Feb 21;192(4):547-56. PubMed: 21321098. Categories: ApoptoSENS, OncoSENS, RepleniSENS

    Four faces of cellular senescence.

    J Cell Biol. 2011 Feb 21;192(4):547-56.

    Four faces of cellular senescence.

    Rodier F, Campisi J.

    Abstract

    Abstract:

    Cellular senescence is an important mechanism for preventing the proliferation of potential cancer cells. Recently, however, it has become apparent that this process entails more than a simple cessation of cell growth. In addition to suppressing tumorigenesis, cellular senescence might also promote tissue repair and fuel inflammation associated with aging and cancer progression. Thus, cellular senescence might participate in four complex biological processes (tumor suppression, tumor promotion, aging, and tissue repair), some of which have apparently opposing effects. The challenge now is to understand the senescence response well enough to harness its benefits while suppressing its drawbacks.

  • O’Connor MS, Carlson ME, Conboy IM. Differentiation rather than aging of muscle stem cells abolishes their telomerase activity. Biotechnol Prog. 2009 Jul-Aug;25(4):1130-7. PubMed: 19455648. Categories: RepleniSENS

    Differentiation rather than aging of muscle stem cells abolishes their telomerase activity.

    Biotechnol Prog. 2009 Jul-Aug;25(4):1130-7.

    Differentiation rather than aging of muscle stem cells abolishes their telomerase activity.

    O’Connor MS, Carlson ME, Conboy IM.

    Abstract

    Abstract:

    A general feature of stem cells is the ability to routinely proliferate to build, maintain, and repair organ systems. Accordingly, embryonic and germline, as well as some adult stem cells, produce the telomerase enzyme at various levels of expression. Our results show that, while muscle is a largely postmitotic tissue, the muscle stem cells (satellite cells) that maintain this biological system throughout adult life do indeed display robust telomerase activity. Conversely, primary myoblasts (the immediate progeny of satellite cells) quickly and dramatically downregulate telomerase activity. This work thus suggests that satellite cells, and early transient myoblasts, may be more promising therapeutic candidates for regenerative medicine than traditionally utilized myoblast cultures. Muscle atrophy accompanies human aging, and satellite cells endogenous to aged muscle can be triggered to regenerate old tissue by exogenous molecular cues. Therefore, we also examined whether these aged muscle stem cells would produce tissue that is "young" with respect to telomere maintenance. Interestingly, this work shows that the telomerase activity in muscle stem cells is largely retained into old age wintin inbred "long" telomere mice and in wild-derived short telomere mouse strains, and that age-specific telomere shortening is undetectable in the old differentiated muscle fibers of either strain. Summarily, this work establishes that young and old muscle stem cells, but not necessarily their progeny, myoblasts, are likely to produce tissue with normal telomere maintenance when used in molecular and regenerative medicine approaches for tissue repair.

  • Wernig M, Zhao JP, Pruszak J, Hedlund E, Fu D, Soldner F, Broccoli V, Constantine-Paton M, Isacson O, Jaenisch R. Neurons derived from reprogrammed fibroblasts functionally integrate into the fetal brain and improve symptoms of rats with Parkinson's disease. Proc Natl Acad Sci USA 2008;105(15):5856-61. PubMed: 18391196. Categories: RepleniSENS

    Neurons derived from reprogrammed fibroblasts functionally integrate into the fetal brain and improve symptoms of rats with Parkinson's disease.

    Proc Natl Acad Sci USA 2008;105(15):5856-61.

    Neurons derived from reprogrammed fibroblasts functionally integrate into the fetal brain and improve symptoms of rats with Parkinson's disease.

    Wernig M, Zhao JP, Pruszak J, Hedlund E, Fu D, Soldner F, Broccoli V, Constantine-Paton M, Isacson O, Jaenisch R.

    Abstract

    Abstract:

    The long-term goal of nuclear transfer or alternative reprogramming approaches is to create patient-specific donor cells for transplantation therapy, avoiding immunorejection, a major complication in current transplantation medicine. It was recently shown that the four transcription factors Oct4, Sox2, Klf4, and c-Myc induce pluripotency in mouse fibroblasts. However, the therapeutic potential of induced pluripotent stem (iPS) cells for neural cell replacement strategies remained unexplored. Here, we show that iPS cells can be efficiently differentiated into neural precursor cells, giving rise to neuronal and glial cell types in culture. Upon transplantation into the fetal mouse brain, the cells migrate into various brain regions and differentiate into glia and neurons, including glutamatergic, GABAergic, and catecholaminergic subtypes. Electrophysiological recordings and morphological analysis demonstrated that the grafted neurons had mature neuronal activity and were functionally integrated in the host brain. Furthermore, iPS cells were induced to differentiate into dopamine neurons of midbrain character and were able to improve behavior in a rat model of Parkinson's disease upon transplantation into the adult brain. We minimized the risk of tumor formation from the grafted cells by separating contaminating pluripotent cells and committed neural cells using fluorescence-activated cell sorting. Our results demonstrate the therapeutic potential of directly reprogrammed fibroblasts for neuronal cell replacement in the animal model.

  • Ott HC, Matthiesen TS, Goh SK, Black LD, Kren SM, Netoff TI, Taylor DA. Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart. Nat Med 2008;14(2):213-221. PubMed: 18193059. Categories: RepleniSENS

    Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart.

    Nat Med 2008;14(2):213-221.

    Perfusion-decellularized matrix: using nature's platform to engineer a bioartificial heart.

    Ott HC, Matthiesen TS, Goh SK, Black LD, Kren SM, Netoff TI, Taylor DA.

    Abstract

    Abstract:

    About 3,000 individuals in the United States are awaiting a donor heart; worldwide, 22 million individuals are living with heart failure. A bioartificial heart is a theoretical alternative to transplantation or mechanical left ventricular support. Generating a bioartificial heart requires engineering of cardiac architecture, appropriate cellular constituents and pump function. We decellularized hearts by coronary perfusion with detergents, preserved the underlying extracellular matrix, and produced an acellular, perfusable vascular architecture, competent acellular valves and intact chamber geometry. To mimic cardiac cell composition, we reseeded these constructs with cardiac or endothelial cells. To establish function, we maintained eight constructs for up to 28 d by coronary perfusion in a bioreactor that simulated cardiac physiology. By day 4, we observed macroscopic contractions. By day 8, under physiological load and electrical stimulation, constructs could generate pump function (equivalent to about 2% of adult or 25% of 16-week fetal heart function) in a modified working heart preparation.

  • Tabar V, Tomishima M, Panagiotakos G, Wakayama S, Menon J, Chan B, Mizutani E, Al-Shamy G, Ohta H, Wakayama T, Studer L. Therapeutic cloning in individual parkinsonian mice. Nat Med 2008;14(4):379-381. PubMed: 18376409. Categories: RepleniSENS

    Therapeutic cloning in individual parkinsonian mice.

    Nat Med 2008;14(4):379-381.

    Therapeutic cloning in individual parkinsonian mice.

    Tabar V, Tomishima M, Panagiotakos G, Wakayama S, Menon J, Chan B, Mizutani E, Al-Shamy G, Ohta H, Wakayama T, Studer L.

    Abstract

    Abstract:

    Cell transplantation with embryonic stem (ES) cell progeny requires immunological compatibility with host tissue. 'Therapeutic cloning' is a strategy to overcome this limitation by generating nuclear transfer (nt)ES cells that are genetically matched to an individual. Here we establish the feasibility of treating individual mice via therapeutic cloning. Derivation of 187 ntES cell lines from 24 parkinsonian mice, dopaminergic differentiation, and transplantation into individually matched host mice showed therapeutic efficacy and lack of immunological response.

  • O'Rourke MF. Arterial aging: pathophysiological principles Vasc Med. 2007 Nov;12(4):329-41 PubMed: 18048471. Categories: GlycoSENS, RepleniSENS

    Arterial aging: pathophysiological principles

    Vasc Med. 2007 Nov;12(4):329-41

    Arterial aging: pathophysiological principles

    O'Rourke MF.

    Abstract

    Abstract:

    In the nineteenth century, prior to the introduction of the cuff sphygmomanometer, arteriosclerosis (stiffening of arteries) was recognized by clinicians and by life insurance companies as an indicator of vascular aging and cardiovascular risk, even in asymptomatic individuals. Through the twentieth century, views on aging came to focus on values of systolic and diastolic pressure and on obstructive atherosclerotic disease. Such focus deflected attention from the primary aging change which occurs in all societies, and is represented by stiffening and dilation of the proximal aorta. This review emphasizes the cushioning function of elastic arteries - principally the aorta - and how in youth this results in optimal interaction with the heart, and optimal steady flow through peripheral resistance vessels. Aortic stiffening with age is principally due to fatigue and fracture of elastin lamellae, with transfer of stress to stiffer collagenous components. Stiffening increases left ventricular load and myocardial blood requirement, but limits the capacity for blood supply during diastole. Consequences are cardiac failure and predisposition to ischaemia. The second, under-appreciated effect of aortic stiffening is transmission of flow pulsations downstream into vasodilated organs, principally brain and kidney, where pulsatile energy is dissipated and fragile microvessels are damaged. This accounts for micro infarcts and microhaemorrhages, with specialized cell damage, cognitive decline and renal failure. The aging process can be best monitored by change in the arterial pressure wave rather than by reliance on the cuff sphygmomanometer. This reintroduces the approaches by clinicians and life insurance examiners of the nineteenth century, endorses modern treatments for established disease, and holds the promise of detecting premature arterial degeneration, and better applying lifestyle measures and vasoactive medications to modify the aging process.

  • Masaki H, Ishikawa T, Takahashi S, Okumura M, Sakai N, Haga M, Kominami K, Migita H, McDonald F, Shimada F, Sakurada K. Heterogeneity of pluripotent marker gene expression in colonies generated in human iPS cell induction culture. Stem Cell Res 2007;1(2):105-15. PubMed: 19383391. Categories: RepleniSENS

    Heterogeneity of pluripotent marker gene expression in colonies generated in human iPS cell induction culture.

    Stem Cell Res 2007;1(2):105-15.

    Heterogeneity of pluripotent marker gene expression in colonies generated in human iPS cell induction culture.

    Masaki H, Ishikawa T, Takahashi S, Okumura M, Sakai N, Haga M, Kominami K, Migita H, McDonald F, Shimada F, Sakurada K.

    Abstract

    Abstract:

    Induction of pluripotent stem cells from human fibroblasts has been achieved by the ectopic expression of two different sets of four genes. However, the mechanism of the pluripotent stem cell induction has not been elucidated. Here we identified a marked heterogeneity in colonies generated by the four-gene (Oct3/4, Sox2, c-Myc, and Klf4) transduction method in human neonatal skin-derived cells. The four-gene transduction gave a higher probability of induction for archetypal pluripotent stem cell marker genes (Nanog, TDGF, and Dnmt3b) than for marker genes that are less specific for pluripotent stem cells (CYP26A1 and TERT) in primary induction culture. This tendency may reflect the molecular mechanism underlying the induction of human skin-derived cells into pluripotent stem cells. Among the colonies induced by the four-gene transduction, small cells with a high nucleus-to-cytoplasm ratio could be established by repeated cloning. Subsequently established cell lines were similar to human embryonic stem cells as well as human induced pluripotent stem (iPS) cells derived from adult tissue in morphology, gene expression, long-term self-renewal ability, and teratoma formation. Genome-wide single-nucleotide polymorphism array analysis of the human iPS cell line indicates that the induction process did not induce DNA mutation.

  • Carlson ME, Conboy IM. Loss of stem cell regenerative capacity within aged niches. Aging Cell 2007;6(3):371-382. PubMed: 17381551. Categories: RepleniSENS

    Loss of stem cell regenerative capacity within aged niches.

    Aging Cell 2007;6(3):371-382.

    Loss of stem cell regenerative capacity within aged niches.

    Carlson ME, Conboy IM.

    Abstract

    Abstract:

    This work uncovers novel mechanisms of aging within stem cell niches that are evolutionarily conserved between mice and humans and affect both embryonic and adult stem cells. Specifically, we have examined the effects of aged muscle and systemic niches on key molecular identifiers of regenerative potential of human embryonic stem cells (hESCs) and post-natal muscle stem cells (satellite cells). Our results reveal that aged differentiated niches dominantly inhibit the expression of Oct4 in hESCs and Myf-5 in activated satellite cells, and reduce proliferation and myogenic differentiation of both embryonic and tissue-specific adult stem cells (ASCs). Therefore, despite their general neoorganogenesis potential, the ability of hESCs, and the more differentiated myogenic ASCs to contribute to tissue repair in the old will be greatly restricted due to the conserved inhibitory influence of aged differentiated niches. Significantly, this work establishes that hESC-derived factors enhance the regenerative potential of both young and, importantly, aged muscle stem cells in vitro and in vivo; thus, suggesting that the regenerative outcome of stem cell-based replacement therapies will be determined by a balance between negative influences of aged tissues on transplanted cells and positive effects of embryonic cells on the endogenous regenerative capacity. Comprehensively, this work points toward novel venues for in situ restoration of tissue repair in the old and identifies critical determinants of successful cell-replacement therapies for aged degenerating organs.

  • Carlson ME, O’Connor MS, Hsu M, Conboy IM. Notch signaling pathway and tissue engineering. Front Biosci. 2007;12:5143-56. PubMed: 17569636. Categories: RepleniSENS

    Notch signaling pathway and tissue engineering.

    Front Biosci. 2007;12:5143-56.

    Notch signaling pathway and tissue engineering.

    Carlson ME, O’Connor MS, Hsu M, Conboy IM.

    Abstract

    Abstract:

    The Notch pathway is a signaling network essential for proper organ development in an embryo, and is indispensable for tissue regeneration in the adult. This key regulatory signaling network is evolutionarily conserved in all metazoans and is continually utilized for the building, maintenance and repair of diverse organs and tissues. Importantly, dysfunctions in the Notch pathway have been demonstrated to result in oncogenic transformation, such as in lymphoid cancers, and have been linked to the pathogenesis of several inherited human diseases. Therefore, the ability to regulate Notch signaling intensity both positively and negatively has a very high therapeutic relevance. Adapting this pathway for tissue engineering applications has great potential to spear-head the development of smart biomaterials to deliberately control cell-fate decisions and lead to designer ex vivo morphogenesis. This review describes the components of Notch-specific signal transduction, presents the role of the Notch signaling network in constructing and repairing multiple organ systems, summarizes the Notch-related pathologies, outlines current advances in the deliberate modulation of the Notch pathway in bioengineering applications, and introduces future perspectives on the use of Notch pathway manipulations as a powerful universal tool in tissue engineering and in the orchestration of stem cell responses. This review also summarizes the existing bioengineering methods most suitable for the deliberate manipulation of Notch signaling, such as smart biomaterials able to pattern Notch ligands or to create gradients of Notch agonists and antagonists. Such methods will likely facilitate the engineering and dynamic remodeling of tissues composed of stem, progenitor and differentiated cells derived from an initially equivalent cell population.

  • Okita K, Ichisaka T, Yamanaka S. Generation of germline-competent induced pluripotent stem cells. Nature 2007;448(7151):313-317. PubMed: 17554338. Categories: RepleniSENS

    Generation of germline-competent induced pluripotent stem cells.

    Nature 2007;448(7151):313-317.

    Generation of germline-competent induced pluripotent stem cells.

    Okita K, Ichisaka T, Yamanaka S.

    Abstract

    Abstract:

    We have previously shown that pluripotent stem cells can be induced from mouse fibroblasts by retroviral introduction of Oct3/4 (also called Pou5f1), Sox2, c-Myc and Klf4, and subsequent selection for Fbx15 (also called Fbxo15) expression. These induced pluripotent stem (iPS) cells (hereafter called Fbx15 iPS cells) are similar to embryonic stem (ES) cells in morphology, proliferation and teratoma formation; however, they are different with regards to gene expression and DNA methylation patterns, and fail to produce adult chimaeras. Here we show that selection for Nanog expression results in germline-competent iPS cells with increased ES-cell-like gene expression and DNA methylation patterns compared with Fbx15 iPS cells. The four transgenes (Oct3/4, Sox2, c-myc and Klf4) were strongly silenced in Nanog iPS cells. We obtained adult chimaeras from seven Nanog iPS cell clones, with one clone being transmitted through the germ line to the next generation. Approximately 20% of the offspring developed tumours attributable to reactivation of the c-myc transgene. Thus, iPS cells competent for germline chimaeras can be obtained from fibroblasts, but retroviral introduction of c-Myc should be avoided for clinical application.

  • Wernig M, Meissner A, Foreman R, Brambrink T, Ku M, Hochedlinger K, Bernstein BE, Jaenisch R. In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state. Nature 2007;448(7151):318-324. PubMed: 17554336. Categories: RepleniSENS

    In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state.

    Nature 2007;448(7151):318-324.

    In vitro reprogramming of fibroblasts into a pluripotent ES-cell-like state.

    Wernig M, Meissner A, Foreman R, Brambrink T, Ku M, Hochedlinger K, Bernstein BE, Jaenisch R.

    Abstract

    Abstract:

    Nuclear transplantation can reprogramme a somatic genome back into an embryonic epigenetic state, and the reprogrammed nucleus can create a cloned animal or produce pluripotent embryonic stem cells. One potential use of the nuclear cloning approach is the derivation of 'customized' embryonic stem (ES) cells for patient-specific cell treatment, but technical and ethical considerations impede the therapeutic application of this technology. Reprogramming of fibroblasts to a pluripotent state can be induced in vitro through ectopic expression of the four transcription factors Oct4 (also called Oct3/4 or Pou5f1), Sox2, c-Myc and Klf4. Here we show that DNA methylation, gene expression and chromatin state of such induced reprogrammed stem cells are similar to those of ES cells. Notably, the cells-derived from mouse fibroblasts-can form viable chimaeras, can contribute to the germ line and can generate live late-term embryos when injected into tetraploid blastocysts. Our results show that the biological potency and epigenetic state of in-vitro-reprogrammed induced pluripotent stem cells are indistinguishable from those of ES cells.

  • Takahashi K, Tanabe K, Ohnuki M, Narita M, Ichisaka T, Tomoda K, Yamanaka S. Induction of pluripotent stem cells from adult human fibroblasts by defined factors. Cell 2007;131(5):861-872. PubMed: 18035408. Categories: RepleniSENS

    Induction of pluripotent stem cells from adult human fibroblasts by defined factors.

    Cell 2007;131(5):861-872.

    Induction of pluripotent stem cells from adult human fibroblasts by defined factors.

    Takahashi K, Tanabe K, Ohnuki M, Narita M, Ichisaka T, Tomoda K, Yamanaka S.

    Abstract

    Abstract:

    Successful reprogramming of differentiated human somatic cells into a pluripotent state would allow creation of patient- and disease-specific stem cells. We previously reported generation of induced pluripotent stem (iPS) cells, capable of germline transmission, from mouse somatic cells by transduction of four defined transcription factors. Here, we demonstrate the generation of iPS cells from adult human dermal fibroblasts with the same four factors: Oct3/4, Sox2, Klf4, and c-Myc. Human iPS cells were similar to human embryonic stem (ES) cells in morphology, proliferation, surface antigens, gene expression, epigenetic status of pluripotent cell-specific genes, and telomerase activity. Furthermore, these cells could differentiate into cell types of the three germ layers in vitro and in teratomas. These findings demonstrate that iPS cells can be generated from adult human fibroblasts.

  • Yu J, Vodyanik MA, Smuga-Otto K, Antosiewicz-Bourget J, Frane JL, Tian S, Nie J, Jonsdottir GA, Ruotti V, Stewart R, Slukvin II, Thomson JA. Induced pluripotent stem cell lines derived from human somatic cells. Science 2007;318(5858):1917-1920. PubMed: 18029452. Categories: RepleniSENS

    Induced pluripotent stem cell lines derived from human somatic cells.

    Science 2007;318(5858):1917-1920.

    Induced pluripotent stem cell lines derived from human somatic cells.

    Yu J, Vodyanik MA, Smuga-Otto K, Antosiewicz-Bourget J, Frane JL, Tian S, Nie J, Jonsdottir GA, Ruotti V, Stewart R, Slukvin II, Thomson JA.

    Abstract

    Abstract:

    Somatic cell nuclear transfer allows trans-acting factors present in the mammalian oocyte to reprogram somatic cell nuclei to an undifferentiated state. We show that four factors (OCT4, SOX2, NANOG, and LIN28) are sufficient to reprogram human somatic cells to pluripotent stem cells that exhibit the essential characteristics of embryonic stem (ES) cells. These induced pluripotent human stem cells have normal karyotypes, express telomerase activity, express cell surface markers and genes that characterize human ES cells, and maintain the developmental potential to differentiate into advanced derivatives of all three primary germ layers. Such induced pluripotent human cell lines should be useful in the production of new disease models and in drug development, as well as for applications in transplantation medicine, once technical limitations (for example, mutation through viral integration) are eliminated.

  • Brambrink T, Hochedlinger K, Bell G, Jaenisch R. ES cells derived from cloned and fertilized blastocysts are transcriptionally and functionally indistinguishable. Proc Natl Acad Sci USA 2006;103(4):933-938. PubMed: 16418286. Categories: RepleniSENS

    ES cells derived from cloned and fertilized blastocysts are transcriptionally and functionally indistinguishable.

    Proc Natl Acad Sci USA 2006;103(4):933-938.

    ES cells derived from cloned and fertilized blastocysts are transcriptionally and functionally indistinguishable.

    Brambrink T, Hochedlinger K, Bell G, Jaenisch R.

    Abstract

    Abstract:

    Reproductive cloning is uniformly rejected as a valid technology in humans because of the severely abnormal phenotypes seen in cloned animals. Gene expression aberrations observed in tissues of cloned animals have also raised concerns regarding the therapeutic application of "customized" embryonic stem (ES) cells derived by nuclear transplantation (NT) from a patient's somatic cells. Although previous experiments in mice have demonstrated that the developmental potential of ES cells derived from cloned blastocysts (NT-ES cells) is identical to that of ES cells derived from fertilized blastocysts, a systematic molecular characterization of NT-ES cell lines is lacking. To investigate whether transcriptional aberrations, similar to those observed in tissues of cloned mice, also occur in NT-ES cells, we have compared transcriptional profiles of 10 mouse NT- and fertilization-derived-ES cell lines. We report here that the ES cell lines derived from cloned and fertilized mouse blastocysts are indistinguishable based on their transcriptional profiles, consistent with their normal developmental potential. Our results indicate that, in contrast to embryonic and fetal development of clones, the process of NT-ES cell derivation rigorously selects for those immortal cells that have erased the "epigenetic memory" of the donor nucleus and, thus, become functionally equivalent. Our findings support the notion that ES cell lines derived from cloned or fertilized blastocysts have an identical therapeutic potential.

  • Srivastava AS, Shenouda S, Mishra R, Carrier E. Transplanted embryonic stem cells successfully survive, proliferate, and migrate to damaged regions of the mouse brain. Stem Cells 2006;24(7):1689-1694. PubMed: 16574752. Categories: RepleniSENS

    Transplanted embryonic stem cells successfully survive, proliferate, and migrate to damaged regions of the mouse brain.

    Stem Cells 2006;24(7):1689-1694.

    Transplanted embryonic stem cells successfully survive, proliferate, and migrate to damaged regions of the mouse brain.

    Srivastava AS, Shenouda S, Mishra R, Carrier E.

    Abstract

    Abstract:

    An understanding of feasibility of implanting embryonic stem cells (ESCs), their behavior of migration in response to lesions induced in brain tissues, and the mechanism of their in vivo differentiation into neighboring neural cells is essential for developing and refining ESC transplantation strategies for repairing damages in the nervous system, as well as for understanding the molecular mechanism underlying neurogenesis. We hypothesized that damaged neural tissues offer a niche to which injected ESCs can migrate and differentiate into the neural cells. We inflicted damage in the murine (C57BL/6) brain by injecting phosphate-buffered saline into the left frontal and right caudal regions and confirmed neural damage by histochemistry. Enhanced yellow fluorescent protein-expressing ESCs were injected into the nondamaged left caudal portion of the brain. Using immunohistochemistry and fluorescent microscopy, we observed migration of ESCs from the injection site (left caudal) to the damaged site (right caudal and left frontal). Survival of the injected ESCs was confirmed by the real-time polymerase chain reaction analysis of stemness genes such as Oct4, Sox2, and FGF4. The portions of the damaged neural tissues containing ESCs demonstrated a fourfold increase in expression of these genes after 1 week of injection in comparison with the noninjected ESC murine brain, suggesting proliferation. An increased level of platelet-derived growth factor receptor demonstrated that ESCs responded to damaged neural tissues, migrated to the damaged site of the brain, and proliferated. These results demonstrate that undifferentiated ESCs migrate to the damaged regions of brain tissue, engraft, and proliferate. Thus, damaged brain tissue provides a niche that attracts ESCs to migrate and proliferate.

  • Dyce PW, Wen L, Li J. In vitro germline potential of stem cells derived from fetal porcine skin. Nat Cell Biol 2006;8(4):384-390. PubMed: 16565707. Categories: RepleniSENS

    In vitro germline potential of stem cells derived from fetal porcine skin.

    Nat Cell Biol 2006;8(4):384-390.

    In vitro germline potential of stem cells derived from fetal porcine skin.

    Dyce PW, Wen L, Li J.

    Abstract

    Abstract:

    Two of the unanswered questions in mammalian developmental biology are when and where the fate of the germ cell is specified. Here, we report that stem cells isolated from the skin of porcine fetuses have the intrinsic ability to differentiate into oocyte-like cells. When differentiation was induced, a subpopulation of these cells expressed markers such as Oct4, Growth differentiation factor 9b (GDF9b), the Deleted in Azoospermia-like (DAZL) gene and Vasa - all consistent with germ-cell formation. On further differentiation, these cells formed follicle-like aggregates that secreted oestradiol and progesterone and responded to gonadotropin stimulation. Some of these aggregates extruded large oocyte-like cells that expressed oocyte markers, such as zona pellucida, and the meiosis marker, synaptonemal complex protein 3 (SCP3). Some of these oocyte-like cells spontaneously developed into parthenogenetic embryo-like structures. The ability to generate oocyte-like cells from skin-derived cells may offer new possibilities for tissue therapy and provide a new in vitro model to study germ-cell formation and oogenesis.

  • Deshpande DM, Kim YS, Martinez T, Carmen J, Dike S, Shats I, Rubin LL, Drummond J, Krishnan C, Hoke A, Maragakis N, Shefner J, Rothstein JD, Kerr DA. Recovery from paralysis in adult rats using embryonic stem cells. Ann Neurol 2006;60(1):32-44. PubMed: 16802299. Categories: RepleniSENS

    Recovery from paralysis in adult rats using embryonic stem cells.

    Ann Neurol 2006;60(1):32-44.

    Recovery from paralysis in adult rats using embryonic stem cells.

    Deshpande DM, Kim YS, Martinez T, Carmen J, Dike S, Shats I, Rubin LL, Drummond J, Krishnan C, Hoke A, Maragakis N, Shefner J, Rothstein JD, Kerr DA.

    Abstract

    Abstract:

    OBJECTIVE: We explored the potential of embryonic stem cell-derived motor neurons to functionally replace those cells destroyed in paralyzed adult rats. METHODS: We administered a phosphodiesterase type 4 inhibitor and dibutyryl cyclic adenosine monophosphate to overcome myelin-mediated repulsion and provided glial cell-derived neurotrophic factor within the sciatic nerve to attract transplanted embryonic stem cell-derived axons toward skeletal muscle targets. RESULTS: We found that these strategies significantly increased the success of transplanted axons extending out of the spinal cord into ventral roots. Furthermore, transplant-derived axons reached muscle, formed neuromuscular junctions, were physiologically active, and mediated partial recovery from paralysis. INTERPRETATION: We conclude that restoration of functional motor units by embryonic stem cells is possible and represents a potential therapeutic strategy for patients with paralysis. To our knowledge, this is the first report of the anatomical and functional replacement of a motor neuron circuit within the adult mammalian host.

  • Lund RD, Wang S, Klimanskaya I, Holmes T, Ramos-Kelsey R, Lu B, Girman S, Bischoff N, Sauvé Y, Lanza R. Human embryonic stem cell–derived cells rescue visual function in dystrophic RCS rats. Cloning Stem Cells 2006;8(3):189-199. PubMed: 17009895. Categories: RepleniSENS

    Human embryonic stem cell–derived cells rescue visual function in dystrophic RCS rats.

    Cloning Stem Cells 2006;8(3):189-199.

    Human embryonic stem cell–derived cells rescue visual function in dystrophic RCS rats.

    Lund RD, Wang S, Klimanskaya I, Holmes T, Ramos-Kelsey R, Lu B, Girman S, Bischoff N, Sauvé Y, Lanza R.

    Abstract

    Abstract:

    Embryonic stem cells promise to provide a well-characterized and reproducible source of replacement tissue for human clinical studies. An early potential application of this technology is the use of retinal pigment epithelium (RPE) for the treatment of retinal degenerative diseases such as macular degeneration. Here we show the reproducible generation of RPE (67 passageable cultures established from 18 different hES cell lines); batches of RPE derived from NIH-approved hES cells (H9) were tested and shown capable of extensive photoreceptor rescue in an animal model of retinal disease, the Royal College of Surgeons (RCS) rat, in which photoreceptor loss is caused by a defect in the adjacent retinal pigment epithelium. Improvement in visual performance was 100% over untreated controls (spatial acuity was approximately 70% that of normal nondystrophic rats) without evidence of untoward pathology. The use of somatic cell nuclear transfer (SCNT) and/or the creation of banks of reduced complexity human leucocyte antigen (HLA) hES-RPE lines could minimize or eliminate the need for immunosuppressive drugs and/or immunomodulatory protocols.

  • Lunde K, Solheim S, Aakhus S, Arnesen H, Abdelnoor M, Egeland T, Endresen K, Ilebekk A, Mangschau A, Fjeld JG, Smith HJ, Taraldsrud E, Grogaard HK, Bjornerheim R, Brekke M, Muller C, Hopp E, Ragnarsson A, Brinchmann JE, Forfang K. Intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction. N Engl J Med 2006;355(12):1199-1209. PubMed: 16990383. Categories: RepleniSENS

    Intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction.

    N Engl J Med 2006;355(12):1199-1209.

    Intracoronary injection of mononuclear bone marrow cells in acute myocardial infarction.

    Lunde K, Solheim S, Aakhus S, Arnesen H, Abdelnoor M, Egeland T, Endresen K, Ilebekk A, Mangschau A, Fjeld JG, Smith HJ, Taraldsrud E, Grogaard HK, Bjornerheim R, Brekke M, Muller C, Hopp E, Ragnarsson A, Brinchmann JE, Forfang K.

    Abstract

    Abstract:

    BACKGROUND: Previous studies have shown improvement in left ventricular function after intracoronary injection of autologous cells derived from bone marrow (BMC) in the acute phase of myocardial infarction. We designed a randomized, controlled trial to further investigate the effects of this treatment. METHODS: Patients with acute ST-elevation myocardial infarction of the anterior wall treated with percutaneous coronary intervention were randomly assigned to the group that underwent intracoronary injection of autologous mononuclear BMC or to the control group, in which neither aspiration nor sham injection was performed. Left ventricular function was assessed with the use of electrocardiogram-gated single-photon-emission computed tomography (SPECT) and echocardiography at baseline and magnetic resonance imaging (MRI) 2 to 3 weeks after the infarction. These procedures were repeated 6 months after the infarction. End points were changes in the left ventricular ejection fraction (LVEF), end-diastolic volume, and infarct size. RESULTS: Of the 50 patients assigned to treatment with mononuclear BMC, 47 underwent intracoronary injection of the cells at a median of 6 days after myocardial infarction. There were 50 patients in the control group. The mean (+/-SD) change in LVEF, measured with the use of SPECT, between baseline and 6 months after infarction for all patients was 7.6+/-10.4 percentage points. The effect of BMC treatment on the change in LVEF was an increase of 0.6 percentage point (95% confidence interval [CI], -3.4 to 4.6; P=0.77) on SPECT, an increase of 0.6 percentage point (95% CI, -2.6 to 3.8; P=0.70) on echocardiography, and a decrease of 3.0 percentage points (95% CI, 0.1 to -6.1; P=0.054) on MRI. The two groups did not differ significantly in changes in left ventricular end-diastolic volume or infarct size and had similar rates of adverse events. CONCLUSIONS: With the methods used, we found no effects of intracoronary injection of autologous mononuclear BMC on global left ventricular function.

  • Schachinger V, Erbs S, Elsasser A, Haberbosch W, Hambrecht R, Holschermann H, Yu J, Corti R, Mathey DG, Hamm CW, Suselbeck T, Assmus B, Tonn T, Dimmeler S, Zeiher AM; REPAIR-AMI Investigators. Intracoronary bone marrow-derived progenitor cells in acute myocardial infarction. N Engl J Med 2006;355(12):1210-1221. PubMed: 16990384. Categories: RepleniSENS

    Intracoronary bone marrow-derived progenitor cells in acute myocardial infarction.

    N Engl J Med 2006;355(12):1210-1221.

    Intracoronary bone marrow-derived progenitor cells in acute myocardial infarction.

    Schachinger V, Erbs S, Elsasser A, Haberbosch W, Hambrecht R, Holschermann H, Yu J, Corti R, Mathey DG, Hamm CW, Suselbeck T, Assmus B, Tonn T, Dimmeler S, Zeiher AM; REPAIR-AMI Investigators.

    Abstract

    Abstract:

    BACKGROUND: Pilot trials suggest that the intracoronary administration of autologous progenitor cells may improve left ventricular function after acute myocardial infarction. METHODS: In a multicenter trial, we randomly assigned 204 patients with acute myocardial infarction to receive an intracoronary infusion of progenitor cells derived from bone marrow (BMC) or placebo medium into the infarct artery 3 to 7 days after successful reperfusion therapy. RESULTS: At 4 months, the absolute improvement in the global left ventricular ejection fraction (LVEF) was significantly greater in the BMC group than in the placebo group (mean [+/-SD] increase, 5.5+/-7.3% vs. 3.0+/-6.5%; P=0.01). Patients with a baseline LVEF at or below the median value of 48.9% derived the most benefit (absolute improvement in LVEF, 5.0%; 95% confidence interval, 2.0 to 8.1). At 1 year, intracoronary infusion of BMC was associated with a reduction in the prespecified combined clinical end point of death, recurrence of myocardial infarction, and any revascularization procedure (P=0.01). CONCLUSIONS: Intracoronary administration of BMC is associated with improved recovery of left ventricular contractile function in patients with acute myocardial infarction. Large-scale studies are warranted to examine the potential effects of progenitor-cell administration on morbidity and mortality.

  • Klimanskaya I, Chung Y, Becker S, Lu SJ, Lanza R. Human embryonic stem cell lines derived from single blastomeres. Nature 2006;444(7118):481-5. PubMed: 16929302. Categories: RepleniSENS

    Human embryonic stem cell lines derived from single blastomeres.

    Nature 2006;444(7118):481-5.

    Human embryonic stem cell lines derived from single blastomeres.

    Klimanskaya I, Chung Y, Becker S, Lu SJ, Lanza R.

    Abstract

    Abstract:

    The derivation of human embryonic stem (hES) cells currently requires the destruction of ex utero embryos. A previous study in mice indicates that it might be possible to generate embryonic stem (ES) cells using a single-cell biopsy similar to that used in preimplantation genetic diagnosis (PGD), which does not interfere with the embryo's developmental potential. By growing the single blastomere overnight, the resulting cells could be used for both genetic testing and stem cell derivation without affecting the clinical outcome of the procedure. Here we report a series of ten separate experiments demonstrating that hES cells can be derived from single blastomeres. In this proof-of-principle study, multiple biopsies were taken from each embryo using micromanipulation techniques and none of the biopsied embryos were allowed to develop in culture. Nineteen ES-cell-like outgrowths and two stable hES cell lines were obtained. The latter hES cell lines maintained undifferentiated proliferation for more than eight months, and showed normal karyotype and expression of markers of pluripotency, including Oct-4, SSEA-3, SSEA-4, TRA-1-60, TRA-1-81, nanog and alkaline phosphatase. These cells retained the potential to form derivatives of all three embryonic germ layers both in vitro and in teratomas. The ability to create new stem cell lines and therapies without destroying embryos would address the ethical concerns of many, and allow the generation of matched tissue for children and siblings born from transferred PGD embryos.

  • Assmus B, Honold J, Schachinger V, Britten MB, Fischer-Rasokat U, Lehmann R, Teupe C, Pistorius K, Martin H, Abolmaali ND, Tonn T, Dimmeler S, Zeiher AM. Transcoronary transplantation of progenitor cells after myocardial infarction. N Engl J Med 2006;355(12):1222-1232. PubMed: 16990385. Categories: RepleniSENS

    Transcoronary transplantation of progenitor cells after myocardial infarction.

    N Engl J Med 2006;355(12):1222-1232.

    Transcoronary transplantation of progenitor cells after myocardial infarction.

    Assmus B, Honold J, Schachinger V, Britten MB, Fischer-Rasokat U, Lehmann R, Teupe C, Pistorius K, Martin H, Abolmaali ND, Tonn T, Dimmeler S, Zeiher AM.

    Abstract

    Abstract:

    BACKGROUND: Pilot studies suggest that intracoronary transplantation of progenitor cells derived from bone marrow (BMC) or circulating blood (CPC) may improve left ventricular function after acute myocardial infarction. The effects of cell transplantation in patients with healed myocardial infarction are unknown. METHODS: After an initial pilot trial involving 17 patients, we randomly assigned, in a controlled crossover study, 75 patients with stable ischemic heart disease who had had a myocardial infarction at least 3 months previously to receive either no cell infusion (23 patients) or infusion of CPC (24 patients) or BMC (28 patients) into the patent coronary artery supplying the most dyskinetic left ventricular area. The patients in the control group were subsequently randomly assigned to receive CPC or BMC, and the patients who initially received BMC or CPC crossed over to receive CPC or BMC, respectively, at 3 months' follow-up. RESULTS: The absolute change in left ventricular ejection fraction was significantly greater among patients receiving BMC (+2.9 percentage points) than among those receiving CPC (-0.4 percentage point, P=0.003) or no infusion (-1.2 percentage points, P<0.001). The increase in global cardiac function was related to significantly enhanced regional contractility in the area targeted by intracoronary infusion of BMC. The crossover phase of the study revealed that intracoronary infusion of BMC was associated with a significant increase in global and regional left ventricular function, regardless of whether patients crossed over from control to BMC or from CPC to BMC. CONCLUSIONS: Intracoronary infusion of progenitor cells is safe and feasible in patients with healed myocardial infarction. Transplantation of BMC is associated with moderate but significant improvement in the left ventricular ejection fraction after 3 months.

  • Takahashi K, Yamanaka S. Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 2006;126(4):663-676. PubMed: 16904174. Categories: RepleniSENS

    Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors.

    Cell 2006;126(4):663-676.

    Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors.

    Takahashi K, Yamanaka S.

    Abstract

    Abstract:

    Differentiated cells can be reprogrammed to an embryonic-like state by transfer of nuclear contents into oocytes or by fusion with embryonic stem (ES) cells. Little is known about factors that induce this reprogramming. Here, we demonstrate induction of pluripotent stem cells from mouse embryonic or adult fibroblasts by introducing four factors, Oct3/4, Sox2, c-Myc, and Klf4, under ES cell culture conditions. Unexpectedly, Nanog was dispensable. These cells, which we designated iPS (induced pluripotent stem) cells, exhibit the morphology and growth properties of ES cells and express ES cell marker genes. Subcutaneous transplantation of iPS cells into nude mice resulted in tumors containing a variety of tissues from all three germ layers. Following injection into blastocysts, iPS cells contributed to mouse embryonic development. These data demonstrate that pluripotent stem cells can be directly generated from fibroblast cultures by the addition of only a few defined factors.

  • Schwartz RS. The politics and promise of stem-cell research. N Engl J Med 2006;355(12):1189-1191. PubMed: 16990380. Categories: RepleniSENS

    The politics and promise of stem-cell research.

    N Engl J Med 2006;355(12):1189-1191.

    The politics and promise of stem-cell research.

    Schwartz RS.

    Abstract

    Abstract:

    No abstract available.

  • Bonde S, Zavazava N. Immunogenicity and engraftment of mouse embryonic stem cells in allogeneic recipients. Stem Cells 2006;24(10):2192-2201. PubMed: 16794265. Categories: RepleniSENS

    Immunogenicity and engraftment of mouse embryonic stem cells in allogeneic recipients.

    Stem Cells 2006;24(10):2192-2201.

    Immunogenicity and engraftment of mouse embryonic stem cells in allogeneic recipients.

    Bonde S, Zavazava N.

    Abstract

    Abstract:

    Embryonic stem cells (ESCs) are pluripotent and therefore able to differentiate both in vitro and in vivo into specialized tissues under appropriate conditions, a property that could be exploited for cellular therapies. However, the immunological nature of these cells in vivo has not been well understood. In vitro, mouse-derived ESCs fail to stimulate T cells, but they abrogate ongoing alloresponses by a process that requires cell-cell contact. We further show that despite a high expression of the NKG2D ligand retinoic acid early inducible-1 by mouse ESCs, they remain resistant to natural killer cell lysis. In vivo, allogeneic mouse ESCs populate the thymus, spleen, and liver of sublethally irradiated allogeneic host mice, inducing apoptosis to T cells and establishing multilineage mixed chimerism that significantly inhibits alloresponses to donor major histocompatibility complex antigens. Immunohistochemical imaging revealed a significant percentage of ESC-derived cells in the splenic marginal zones, but not in the follicles. Taken together, the data presented here reveal that nondifferentiated mouse embryonic stem cells are non-immunogenic and appear to populate lymphoid tissues in vivo, leading to T-cell deletion by apoptosis.

  • Kolossov E, Bostani T, Roell W, Breitbach M, Pillekamp F, Nygren JM, Sasse P, Rubenchik O, Fries JW, Wenzel D, Geisen C, Xia Y, Lu Z, Duan Y, Kettenhofen R, Jovinge S, Bloch W, Bohlen H, Welz A, Hescheler J, Jacobsen SE, Fleischmann BK. Engraftment of engineered ES cell-derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium. J Exp Med 2006;203(10):2315-2327. PubMed: 16954371. Categories: RepleniSENS

    Engraftment of engineered ES cell-derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium.

    J Exp Med 2006;203(10):2315-2327.

    Engraftment of engineered ES cell-derived cardiomyocytes but not BM cells restores contractile function to the infarcted myocardium.

    Kolossov E, Bostani T, Roell W, Breitbach M, Pillekamp F, Nygren JM, Sasse P, Rubenchik O, Fries JW, Wenzel D, Geisen C, Xia Y, Lu Z, Duan Y, Kettenhofen R, Jovinge S, Bloch W, Bohlen H, Welz A, Hescheler J, Jacobsen SE, Fleischmann BK.

    Abstract

    Abstract:

    Cellular cardiomyoplasty is an attractive option for the treatment of severe heart failure. It is, however, still unclear and controversial which is the most promising cell source. Therefore, we investigated and examined the fate and functional impact of bone marrow (BM) cells and embryonic stem cell (ES cell)-derived cardiomyocytes after transplantation into the infarcted mouse heart. This proved particularly challenging for the ES cells, as their enrichment into cardiomyocytes and their long-term engraftment and tumorigenicity are still poorly understood. We generated transgenic ES cells expressing puromycin resistance and enhanced green fluorescent protein cassettes under control of a cardiac-specific promoter. Puromycin selection resulted in a highly purified (>99%) cardiomyocyte population, and the yield of cardiomyocytes increased 6-10-fold because of induction of proliferation on purification. Long-term engraftment (4-5 months) was observed when co-transplanting selected ES cell-derived cardiomyocytes and fibroblasts into the injured heart of syngeneic mice, and no teratoma formation was found (n = 60). Although transplantation of ES cell-derived cardiomyocytes improved heart function, BM cells had no positive effects. Furthermore, no contribution of BM cells to cardiac, endothelial, or smooth muscle neogenesis was detected. Hence, our results demonstrate that ES-based cell therapy is a promising approach for the treatment of impaired myocardial function and provides better results than BM-derived cells.

  • Ikeda R, Kurokawa MS, Chiba S, Yoshikawa H, Ide M, Tadokoro M, Nito S, Nakatsuji N, Kondoh Y, Nagata K, Hashimoto T, Suzuki N. Transplantation of neural cells derived from retinoic acid-treated cynomolgus monkey embryonic stem cells successfully improved motor function of hemiplegic mice with experimental brain injury. Neurobiol Dis 2005;20(1):38-48. PubMed: 16137565. Categories: RepleniSENS

    Transplantation of neural cells derived from retinoic acid-treated cynomolgus monkey embryonic stem cells successfully improved motor function of hemiplegic mice with experimental brain injury.

    Neurobiol Dis 2005;20(1):38-48.

    Transplantation of neural cells derived from retinoic acid-treated cynomolgus monkey embryonic stem cells successfully improved motor function of hemiplegic mice with experimental brain injury.

    Ikeda R, Kurokawa MS, Chiba S, Yoshikawa H, Ide M, Tadokoro M, Nito S, Nakatsuji N, Kondoh Y, Nagata K, Hashimoto T, Suzuki N.

    Abstract

    Abstract:

    We induced neural cells by treating cynomolgus monkey embryonic stem (ES) cells with retinoic acid. The treated cells mainly expressed betaIIItubulin. They further differentiated into neurons expressing neurofilament middle chain (NFM) in elongated axons. Half of the cells differentiated into Islet1+ motoneurons in vitro. The monkey ES-derived neural cells were transplanted to hemiplegic mice with experimental brain injury mimicking stroke. The neural cells that had grafted into periventricular area of the mice distributed extensively over the injured cortex. Some of the transplanted cells expressed the neural stem/progenitor marker nestin 2 days after transplantation. The cells expressed markers characteristic of mature motoneurons 28 days after transplantation. Mice with the neural cell graft gradually recovered motor function, whereas control animals remained hemiplegic. This is the first demonstration that neural cells derived from nonhuman primate ES cells have the ability to restore motor function in an animal model of brain injury.

  • Martin MJ, Muotri A, Gage F, Varki A. Human embryonic stem cells express an immunogenic nonhuman sialic acid. Nat Med 2005;11(2):228-232. PubMed: 15685172. Categories: RepleniSENS

    Human embryonic stem cells express an immunogenic nonhuman sialic acid.

    Nat Med 2005;11(2):228-232.

    Human embryonic stem cells express an immunogenic nonhuman sialic acid.

    Martin MJ, Muotri A, Gage F, Varki A.

    Abstract

    Abstract:

    Human embryonic stem cells (HESC) can potentially generate every body cell type, making them excellent candidates for cell- and tissue-replacement therapies. HESC are typically cultured with animal-derived 'serum replacements' on mouse feeder layers. Both of these are sources of the nonhuman sialic acid Neu5Gc, against which many humans have circulating antibodies. Both HESC and derived embryoid bodies metabolically incorporate substantial amounts of Neu5Gc under standard conditions. Exposure to human sera with antibodies specific for Neu5Gc resulted in binding of immunoglobulin and deposition of complement, which would lead to cell killing in vivo. Levels of Neu5Gc on HESC and embryoid bodies dropped after culture in heat-inactivated anti-Neu5Gc antibody-negative human serum, reducing binding of antibodies and complement from high-titer sera, while allowing maintenance of the undifferentiated state. Complete elimination of Neu5Gc would be likely to require using human serum with human feeder layers, ideally starting with fresh HESC that have never been exposed to animal products.

  • Klimanskaya I, Chung Y, Meisner L, Johnson J, West MD, Lanza R. Human embryonic stem cells derived without feeder cells. Lancet 2005;365(9471):1636-1641. PubMed: 15885296. Categories: RepleniSENS

    Human embryonic stem cells derived without feeder cells.

    Lancet 2005;365(9471):1636-1641.

    Human embryonic stem cells derived without feeder cells.

    Klimanskaya I, Chung Y, Meisner L, Johnson J, West MD, Lanza R.

    Abstract

    Abstract:

    BACKGROUND: Human embryonic stem cells are likely to play an important role in the future of regenerative medicine. However, exposure of existing human embryonic stem-cell lines to live animal cells and serum risks contamination with pathogens that could lead to human health risks. We aimed to derive an embryonic stem-cell line without exposure to cells or serum. METHODS: Frozen cleavage-stage embryos were thawed and cultured to the blastocyst stage. Inner cell masses were isolated by immunosurgery and plated onto extracellular-matrix-coated plates that can be easily sterilised. Six established human embryonic stem-cell lines were also maintained with this serum and feeder free culture system. FINDINGS: A new stem-cell line was derived from human embryos under completely cell and serum free conditions. The cells maintained normal karyotype and markers of pluripotency, including octamer binding protein 4 (Oct-4), stage-specific embryonic antigen (SSEA)-3, SSEA-4, tumour-rejection antigen (TRA)-1-60, TRA-1-81, and alkaline phosphatase. After more than 6 months of undifferentiated proliferation, these cells retained the potential to form derivatives of all three embryonic germ layers both in vitro and in teratomas. These properties were also successfully maintained (for more than 30 passages) with the established stem-cell lines. INTERPRETATION: This system eliminates exposure of human embryonic stem cells and their progeny to animal and human feeder layers, and thus the risk of contamination with pathogenic agents capable of transmitting diseases to patients.

  • Takagi Y, Takahashi J, Saiki H, Morizane A, Hayashi T, Kishi Y, Fukuda H, Okamoto Y, Koyanagi M, Ideguchi M, Hayashi H, Imazato T, Kawasaki H, Suemori H, Omachi S, Iida H, Itoh N, Nakatsuji N, Sasai Y, Hashimoto N. Dopaminergic neurons generated from monkey embryonic stem cells function in a Parkinson primate model. J Clin Invest 2005;115(1):102-109. PubMed: 15630449. Categories: RepleniSENS

    Dopaminergic neurons generated from monkey embryonic stem cells function in a Parkinson primate model.

    J Clin Invest 2005;115(1):102-109.

    Dopaminergic neurons generated from monkey embryonic stem cells function in a Parkinson primate model.

    Takagi Y, Takahashi J, Saiki H, Morizane A, Hayashi T, Kishi Y, Fukuda H, Okamoto Y, Koyanagi M, Ideguchi M, Hayashi H, Imazato T, Kawasaki H, Suemori H, Omachi S, Iida H, Itoh N, Nakatsuji N, Sasai Y, Hashimoto N.

    Abstract

    Abstract:

    Parkinson disease (PD) is a neurodegenerative disorder characterized by loss of midbrain dopaminergic (DA) neurons. ES cells are currently the most promising donor cell source for cell-replacement therapy in PD. We previously described a strong neuralizing activity present on the surface of stromal cells, named stromal cell-derived inducing activity (SDIA). In this study, we generated neurospheres composed of neural progenitors from monkey ES cells, which are capable of producing large numbers of DA neurons. We demonstrated that FGF20, preferentially expressed in the substantia nigra, acts synergistically with FGF2 to increase the number of DA neurons in ES cell-derived neurospheres. We also analyzed the effect of transplantation of DA neurons generated from monkey ES cells into 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated (MPTP-treated) monkeys, a primate model for PD. Behavioral studies and functional imaging revealed that the transplanted cells functioned as DA neurons and attenuated MPTP-induced neurological symptoms.

  • Stojkovic M, Stojkovic P, Leary C, Hall VJ, Armstrong L, Herbert M, Nesbitt M, Lako M, Murdoch A. Derivation of a human blastocyst after heterologous nuclear transfer to donated oocytes. Reprod Biomed Online 2005;11(2):226-231. PubMed: 16168222. Categories: RepleniSENS

    Derivation of a human blastocyst after heterologous nuclear transfer to donated oocytes.

    Reprod Biomed Online 2005;11(2):226-231.

    Derivation of a human blastocyst after heterologous nuclear transfer to donated oocytes.

    Stojkovic M, Stojkovic P, Leary C, Hall VJ, Armstrong L, Herbert M, Nesbitt M, Lako M, Murdoch A.

    Abstract

    Abstract:

    This paper describes the derivation of a blastocyst following heterologous nuclear transfer (NT) into a human oocyte. It also demonstrates that a major obstacle to continuing research in human NT is the availability of suitable human oocytes. In this study, 36 oocytes were donated by 11 women undergoing four different treatments and their developmental potential was evaluated after NT. The time from oocyte collection to NT seems to be crucial, and only oocytes that were enucleated within 1 h proved successful. After enucleation of oocytes, fusion with undifferentiated human embryonic stem cells and in-vitro culture, early cleavage and blastocyst development of fused complexes was observed. The DNA fingerprinting comparison of the donor cells and derived blastocyst revealed successful heterologous NT, since both oocytes and donor cells were recovered from different patients. It has therefore been demonstrated that NT can be achieved in humans, using heterologous donor nuclei and surplus and donated oocytes. However, if the promise of this new science is to achieve its potential in the foreseeable future, it will be necessary to identify new sources of oocytes that can be used immediately after retrieval.

  • Menard C, Hagege AA, Agbulut O, Menard C, Hagege AA, Agbulut O. Transplantation of cardiac-committed mouse embryonic stem cells to infarcted sheep myocardium: a preclinical study. Lancet 2005;366(9490):1005-1012. PubMed: 16168783. Categories: RepleniSENS

    Transplantation of cardiac-committed mouse embryonic stem cells to infarcted sheep myocardium: a preclinical study.

    Lancet 2005;366(9490):1005-1012.

    Transplantation of cardiac-committed mouse embryonic stem cells to infarcted sheep myocardium: a preclinical study.

    Menard C, Hagege AA, Agbulut O, Menard C, Hagege AA, Agbulut O.

    Abstract

    Abstract:

    BACKGROUND: Heart failure develops after myocardial infarction and is a major cause of morbidity and mortality. The ability to direct differentiation of embryonic stem cells (ESC) towards a cardiomyogenic phenotype makes them an attractive therapeutic option for cardiac repair, but species-specific and individual-specific immunological imprinting remains a hurdle. Our aim was to ascertain whether the purported immune privilege of ESC allows for their cross-species engraftment in a clinically relevant large-animal model. METHODS: We studied engraftment and differentiation of cardiac-committed mouse ESC in 18 sheep in which a myocardial infarction had been induced; nine controls received medium and nine sheep (five of which were immunosuppressed) received ESC. The gain in myocardial function was measured by echocardiography 1 month after cell transplantation. FINDINGS: Cardiac-committed murine ESC engrafted in infarcted myocardium of immunosuppressed and immunocompetent sheep, and differentiated into mature cardiomyocytes that expressed connexins. Colonisation of the scar area by ESC was accompanied by a functional benefit of the damaged myocardium. Left-ventricular ejection fraction deteriorated in the control group by a median of 9.9% (range -20 to 0.3) relative to baseline (p=0.011) whereas in the treated group it improved by 6.6% (-5.7 to 50.8; comparison between groups p=0.002). INTERPRETATION: These findings obtained in a clinically relevant large-animal model of heart failure strengthen the potential therapeutic use of ESC to regenerate the severely dysfunctional myocardium and bring additional evidence for an immune privilege of these cells.

  • Taylor CJ, Bolton EM, Pocock S, Sharples LD, Pedersen RA, Bradley JA. Banking on human embryonic stem cells: estimating the number of donor cell lines needed for HLA matching. Lancet 2005;366(9502):2019-2025. PubMed: 16338451. Categories: RepleniSENS

    Banking on human embryonic stem cells: estimating the number of donor cell lines needed for HLA matching.

    Lancet 2005;366(9502):2019-2025.

    Banking on human embryonic stem cells: estimating the number of donor cell lines needed for HLA matching.

    Taylor CJ, Bolton EM, Pocock S, Sharples LD, Pedersen RA, Bradley JA.

    Abstract

    Abstract:

    BACKGROUND: Human embryonic stem (hES) cells are a promising source for transplantation to replace diseased or damaged tissue, but their differentiated progeny express human leucocyte antigens (HLAs) that will probably cause graft rejection. The creation of a bank of HLA-typed hES cells, from which a best match could be selected, would help reduce the likelihood of graft rejection. We investigated how many hES cell lines would be needed to make matching possible in most cases. METHODS: The number of hES cell lines needed to achieve varying degrees of HLA match was estimated by use of, as a surrogate for hES-cell donor embryos, blood group and HLA types on a series of 10,000 consecutive UK cadaveric organ donors. The degree of blood group compatibility and HLA matching for a recipient population consisting of 6577 patients registered on the UK kidney transplant waiting list was determined, assuming all donor hES cell lines could provide a transplant for an unlimited number of recipients. FINDINGS: A bank of 150 consecutive donors provided a full match at HLA-A, HLA-B, and HLA-DR for a minority of recipients (<20%); a beneficial match (defined as one HLA-A or one HLA-B mismatch only) or better for 37.9% (range 27.9-47.5); and an HLA-DR match or better for 84.9% (77.5-90.0). Extending the number of donors beyond 150 conferred only a very gradual incremental benefit with respect to HLA matching. A panel of only ten donors homozygous for common HLA types selected from 10,000 donors provided a complete HLA-A, HLA-B and HLA-DR match for 37.7% of recipients, and a beneficial match for 67.4%. INTERPRETATION: Approximately 150 consecutive blood group compatible donors, 100 consecutive blood group O donors, or ten highly selected homozygous donors could provide the maximum practical benefit for HLA matching. The findings from these simulations have practical, political, and ethical implications for the establishment of hES-cell banks.

  • Deten A, Volz HC, Clamors S, Leiblein S, Briest W, Marx G, Zimmer HG. Hematopoietic stem cells do not repair the infarcted mouse heart. Cardiovasc Res 2005;65(1):52-63. PubMed: 15621033. Categories: RepleniSENS

    Hematopoietic stem cells do not repair the infarcted mouse heart.

    Cardiovasc Res 2005;65(1):52-63.

    Hematopoietic stem cells do not repair the infarcted mouse heart.

    Deten A, Volz HC, Clamors S, Leiblein S, Briest W, Marx G, Zimmer HG.

    Abstract

    Abstract:

    OBJECTIVE: Recent reports suggest that hematopoietic stem cells (HSC) can transdifferentiate into cardiomyoctes and contribute to myocardial regeneration after injury. This concept has recently been challenged by studies in which bone-marrow (BM)-derived cells do not acquire a cardiac phenotype after direct injection into ischemic myocardium. METHODS: In this study, we analyzed the effect of increased circulating adult BM cells by stimulation with stem cell factor (SCF; 200 microg/kg/d for 7 days) and granulocyte-colony stimulating factor (G-CSF, 50 microg/kg/d for 7 days) or by peripheral delivery of isolated adult BM cells on morphological and hemodynamic parameters of mouse hearts 6 weeks after induction of chronic myocardial infarction (MI). All animals were splenectomized to prevent sequestration of BM cells 2 weeks prior to the induction of MI. Cytokine treatment was initiated either 3 days prior to or 6 h after MI. Isolated, either whole or by magnetic beads lineage-depleted BM cells were injected via a tail vein 6 h after MI. RESULTS: Left and right ventricular (LV and RV) function revealed no improvement in any treatment group when compared to untreated MI animals at baseline resting conditions as well as after stimulation with norepinephrine (NE; 1, 5, 10, 25, 50, and 100 ng bolus i.v. in 10 microl each) as measured by catherization with ultraminiature 1.4 F tip pressure transducers 6 weeks after MI. Moreover, there was no sign of myocardial regeneration in histological or gene expression analyses. CONCLUSION: Mobilization or i.v. injection of BM cells do not have a measurable effect on cardiac regeneration.

  • Keirstead HS, Nistor G, Bernal G , Totoiu M, Cloutier F, Sharp K, Steward O. Human embryonic stem cell-derived oligodendrocyte progenitor cell transplants remyelinate and restore locomotion after spinal cord injury. J Neurosci 2005;25(19):4694-4705. PubMed: 15888645. Categories: RepleniSENS

    Human embryonic stem cell-derived oligodendrocyte progenitor cell transplants remyelinate and restore locomotion after spinal cord injury.

    J Neurosci 2005;25(19):4694-4705.

    Human embryonic stem cell-derived oligodendrocyte progenitor cell transplants remyelinate and restore locomotion after spinal cord injury.

    Keirstead HS, Nistor G, Bernal G , Totoiu M, Cloutier F, Sharp K, Steward O.

    Abstract

    Abstract:

    Demyelination contributes to loss of function after spinal cord injury, and thus a potential therapeutic strategy involves replacing myelin-forming cells. Here, we show that transplantation of human embryonic stem cell (hESC)-derived oligodendrocyte progenitor cells (OPCs) into adult rat spinal cord injuries enhances remyelination and promotes improvement of motor function. OPCs were injected 7 d or 10 months after injury. In both cases, transplanted cells survived, redistributed over short distances, and differentiated into oligodendrocytes. Animals that received OPCs 7 d after injury exhibited enhanced remyelination and substantially improved locomotor ability. In contrast, when OPCs were transplanted 10 months after injury, there was no enhanced remyelination or locomotor recovery. These studies document the feasibility of predifferentiating hESCs into functional OPCs and demonstrate their therapeutic potential at early time points after spinal cord injury.

  • de Grey ADNJ. Inter-species therapeutic cloning: the looming problem of mitochondrial DNA and two possible solutions. Rejuvenation Res 2004;7(2):95-98. PubMed: 15312296. Categories: MitoSENS, RepleniSENS

    Inter-species therapeutic cloning: the looming problem of mitochondrial DNA and two possible solutions.

    Rejuvenation Res 2004;7(2):95-98.

    Inter-species therapeutic cloning: the looming problem of mitochondrial DNA and two possible solutions.

    de Grey ADNJ.

    Abstract

    Abstract:

    No abstract available.

  • Nygren JM, Jovinge S, Breitbach M, Sawen P, Roll W, Hescheler J, Taneera J, Fleischmann BK, Jacobsen SE. Bone marrow-derived hematopoietic cells generate cardiomyocytes at a low frequency through cell fusion, but not transdifferentiation. Nat Med 2004;10(5):494-501. PubMed: 15107841. Categories: RepleniSENS

    Bone marrow-derived hematopoietic cells generate cardiomyocytes at a low frequency through cell fusion, but not transdifferentiation.

    Nat Med 2004;10(5):494-501.

    Bone marrow-derived hematopoietic cells generate cardiomyocytes at a low frequency through cell fusion, but not transdifferentiation.

    Nygren JM, Jovinge S, Breitbach M, Sawen P, Roll W, Hescheler J, Taneera J, Fleischmann BK, Jacobsen SE.

    Abstract

    Abstract:

    Recent studies have suggested that bone marrow cells might possess a much broader differentiation potential than previously appreciated. In most cases, the reported efficiency of such plasticity has been rather low and, at least in some instances, is a consequence of cell fusion. After myocardial infarction, however, bone marrow cells have been suggested to extensively regenerate cardiomyocytes through transdifferentiation. Although bone marrow-derived cells are already being used in clinical trials, the exact identity, longevity and fate of these cells in infarcted myocardium have yet to be investigated in detail. Here we use various approaches to induce acute myocardial injury and deliver transgenically marked bone marrow cells to the injured myocardium. We show that unfractionated bone marrow cells and a purified population of hematopoietic stem and progenitor cells efficiently engraft within the infarcted myocardium. Engraftment was transient, however, and hematopoietic in nature. In contrast, bone marrow-derived cardiomyocytes were observed outside the infarcted myocardium at a low frequency and were derived exclusively through cell fusion.

  • Ben-Hur T, Idelson M, Khaner H, Pera M, Reinhartz E, Itzik A, Reubinoff BE. Transplantation of human embryonic stem cell-derived neural progenitors improves behavioral deficit in Parkinsonian rats. Stem Cells 2004;22(7):1246-1255. PubMed: 15579643. Categories: RepleniSENS

    Transplantation of human embryonic stem cell-derived neural progenitors improves behavioral deficit in Parkinsonian rats.

    Stem Cells 2004;22(7):1246-1255.

    Transplantation of human embryonic stem cell-derived neural progenitors improves behavioral deficit in Parkinsonian rats.

    Ben-Hur T, Idelson M, Khaner H, Pera M, Reinhartz E, Itzik A, Reubinoff BE.

    Abstract

    Abstract:

    Human embryonic stem cells (hESCs) may potentially serve as a renewable source of cells for transplantation. In Parkinson's disease, hESC-derived dopaminergic (DA) neurons may replace the degenerated neurons in the brain. Here, we generated highly enriched cultures of neural progenitors from hESCs and grafted the progenitors into the striatum of Parkinsonian rats. The grafts survived for at least 12 weeks, the transplanted cells stopped proliferating, and teratomas were not observed. The grafted cells differentiated in vivo into DA neurons, though at a low prevalence similar to that observed following spontaneous differentiation in vitro. Transplanted rats exhibited a significant partial correction of D-amphetamine and apomorphine-induced rotational behavior, along with a significant improvement in stepping and placing non-pharmacological behavioral tests. While transplantation of uncommitted hESC-derived neural progenitors induced partial behavioral recovery, our data indicate that the host-lesioned striatum could not direct the transplanted neural progenitors to acquire a dopaminergic fate. Hence, induction of their differentiation toward a midbrain fate prior to transplantation is probably required for complete correction of behavioral deficit. Our observations encourage further developments for the potential use of hESCs in the treatment of Parkinson's disease.

  • Nisbet MC. Public opinion about stem cell research and human cloning. Public Opinion Quarterly 2004;68(1):131-154. Categories: Beyond the Bench, RepleniSENS

    Public opinion about stem cell research and human cloning.

    Public Opinion Quarterly 2004;68(1):131-154.

    Public opinion about stem cell research and human cloning.

    Nisbet MC.

    Abstract

    Abstract:

    No abstract available.

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