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| Engineering Bone Formation from Human Dental Pulp- and Periodontal Ligament-Derived Cells.
July 9, 2010 at 3:24 PM
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| | Engineering Bone Formation from Human Dental Pulp- and Periodontal Ligament-Derived Cells. Ann Biomed Eng. 2010 Jul 8; Authors: Ikeda H, Sumita Y, Ikeda M, Ikeda H, Okumura T, Sakai E, Nishimura M, Asahina I A robust method for inducing bone formation from cultured dental mesenchymal cells has not been established. In this study, a method for generating bone tissue in vivo from cultured human dental pulp- and periodontal ligament-derived cells (DPCs and PDLCs, respectively) was designed using exogenous bone morphogenetic protein 2 (BMP2). DPCs and PDLCs showed enhanced alkaline phosphatase (ALP) activity and calcified nodule formation in medium containing dexamethasone, beta-glycerophosphate, and ascorbic acid (osteogenic medium). However, the addition of recombinant human bone morphogenetic protein 2 (rhBMP2) to osteogenic medium remarkably increased ALP activity and in vitro calcification above the increases observed with osteogenic medium alone. rhBMP2 also significantly upregulated the expression of osteocalcin, osteopontin, and dentin matrix protein 1 mRNA in both cell types cultured in osteogenic medium. Finally, we detected prominent bone-like tissue formation in vivo when cells had been exposed to rhBMP2 in osteogenic medium. In contrast, treatments with osteogenic medium or rhBMP2 alone could not induce abundant mineralized tissue formation. We propose here that treatment with rhBMP2 in osteogenic medium can make dental mesenchymal tissues a highly useful source of cells for bone tissue engineering. In addition, both DPCs and PDLCs showed similar and remarkable osteo-inducibility. PMID: 20614244 [PubMed - as supplied by publisher] | | |
| Effects of Shear Forces and Pressure on Blood Vessel Function and Metabolism in a Perfusion Bioreactor.
July 9, 2010 at 3:24 PM
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| | Effects of Shear Forces and Pressure on Blood Vessel Function and Metabolism in a Perfusion Bioreactor. Ann Biomed Eng. 2010 Jul 8; Authors: Hoenicka M, Wiedemann L, Puehler T, Hirt S, Birnbaum DE, Schmid C Bovine saphenous veins (BSV) were incubated in a perfusion bioreactor to study vessel wall metabolism and wall structure under tissue engineering conditions. Group 1 vessels were perfused for 4 or 8 days. The viscosity of the medium was increased to that of blood in group 2. Group 3 vessels were additionally strained with luminal pressure. Groups 1-d through 3-d were similar except that BSV were endothelium-denuded before perfusion. Groups 1-a through 3-a used native vessels at elevated flow rates. Group 3 vessels responded significantly better to noradrenaline on day 4, whereas denuded vessels showed attenuated responses (p < 0.001). Tetrazolium dye reduction did not depend on perfusion conditions or time except for denuded vessels. pO(2) gradients across the vessels were independent of time and significantly higher in group 2 (p < 0.001). BSV converted glucose stoichiometrically to lactate except vessels of groups 3, 1-d, and 3-d which released more lactate than glucose could supply (p < 0.001). Group 1 vessels as well as all vessels perfused with elevated flow rates showed a loss of endothelial cells after 4 days, whereas group 2 and 3 vessels retained most of the endothelium. These data suggest that vessel metabolism was not limited by oxygen supply. Shear forces did not affect glucose metabolism but increased oxygen consumption and endothelial cell survival. Luminal pressure caused the utilization of energy sources other than glucose, as long as the endothelium was intact. Therefore, vessel metabolism needs to be monitored during tissue engineering procedures which challenge the constructs with mechanical stimuli. PMID: 20614243 [PubMed - as supplied by publisher] | | |
| Modular enzymatically crosslinked protein polymer hydrogels for in situ gelation.
July 9, 2010 at 3:24 PM
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| | Modular enzymatically crosslinked protein polymer hydrogels for in situ gelation. Biomaterials. 2010 Jul 5; Authors: Davis NE, Ding S, Forster RE, Pinkas DM, Barron AE Biomaterials that mimic the extracellular matrix in both modularity and crosslinking chemistry have the potential to recapitulate the instructive signals that ultimately control cell fate. Toward this goal, modular protein polymer-based hydrogels were created through genetic engineering and enzymatic crosslinking. Animal derived tissue transglutaminase (tTG) and recombinant human transglutaminase (hTG) enzymes were used for coupling two classes of protein polymers containing either lysine or glutamine, which have the recognition substrates for enzymatic crosslinking evenly spaced along the protein backbone. Utilizing tTG under physiological conditions, complete crosslinking occurred within 2 min, as determined by particle tracking microrheology. Hydrogel composition impacted the elastic storage modulus of the gel over 4-fold and also influenced microstructure and degree of swelling, but did not appreciably effect degradation by plasmin. Mouse 3T3 and primary human fibroblasts were cultured in both 2- and 3-dimensions without a decrease in cell viability and displayed spreading in 2D. The properties, which are controlled through the specific nature of the protein polymer precursors, render these gels valuable for in situ therapies. Furthermore, the modular hydrogel composition allows tailoring of mechanical and physical properties for specific tissue engineering applications. PMID: 20609472 [PubMed - as supplied by publisher] | | |
| Murine amniotic fluid stem cells contribute mesenchymal but not epithelial components to reconstituted mammary ducts.
July 9, 2010 at 3:24 PM
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| | Murine amniotic fluid stem cells contribute mesenchymal but not epithelial components to reconstituted mammary ducts. Stem Cell Res Ther. 2010 Jul 7;1(4):20 Authors: Klemmt PA, Vafaizadeh V, Groner B ABSTRACT: INTRODUCTION: Amniotic fluid harbors cells indicative of all three germ layers and pluripotent fetal amniotic fluid stem cells (AFS) are considered as potentially valuable for applications in cellular therapy and tissue engineering. We investigated if it is possible to direct the cell fate of AFS in vivo by transplantation experiments into a particular microenvironment, the mammary fat pad. This microenvironment provides the prerequisites to study stem cell function and the communication between mesenchymal and epithelial cells. Upon clearance of the endogenous epithelium, the ductal tree can be reconstituted by the transfer of exogenously provided mammary stem cells. Analogously, exogenously provided stem cells from other tissues can be investigated for their potential to contribute to mammary gland regeneration. METHODS: We derived pluripotent murine AFS, measured the expression of stem cell markers and confirmed their in vitro differentiation potential. AFS were transplanted into cleared and non cleared fat pads of immunocompromised mice to evaluate their ability to assume particular cell fates under the instructive conditions of the fat pad microenvironment and the hormonal stimulation during pregnancy. RESULTS: Transplantation of AFS into cleared fat pads alone or in the presence of exogenous mammary epithelial cells caused their differentiation into stroma and adipocytes and replaced endogenous mesenchymal components surrounding the ducts in co-transplantation experiments. Similarly, transplantation of AFS into fat pads which had not been previously cleared, led to AFS derived stromal cells surrounding the elongating endogenous ducts. AFS expressed the marker protein -SMA, but did not integrate into the myoepithelial cell layer of the ducts in virgin mice. Upon pregnancy a small number of AFS derived cells were present in acinar structures. CONCLUSIONS: Our data demonstrate that the microenvironmental cues of the mammary fat pad cause AFS to participate in mammary gland regeneration by providing mesenchymal components to emerging glandular structures, but do not incorporate or differentiate into ductal epithelial cells. PMID: 20609228 [PubMed - as supplied by publisher] | | |
| A novel virally-inactivated human platelet lysate preparation rich in TGF-beta, EGF and IGF, depleted of PDGF and VEGF.
July 9, 2010 at 3:24 PM
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| | A novel virally-inactivated human platelet lysate preparation rich in TGF-beta, EGF and IGF, depleted of PDGF and VEGF. Biotechnol Appl Biochem. 2010 Jul 8; Authors: Burnouf PA, Yuan PK, Su CY, Kuo YP, Chou ML, Su CH, Tseng YH, Lin CT, Burnouf T There is emerging interest in the use of standardized virally-inactivated human platelet lysate preparations rich in growth factors (GF) for cell cultures, cell therapy and clinical applications. Here we report a simple process to prepare a virally-inactivated platelet lysate preparation rich in TGF-beta1/EGF/IGF and depleted of PDGF and VEGF. Apheresis platelet concentrates were treated by the solvent-detergent (S/D) viral inactivation procedure, then subjected to one oil extraction followed by adsorption with activated charcoal, and finally sterile-filtered. The resulting preparation contained a mean of 368.4, 2.4, and 54.7 ng/mL of TGF-beta1, EGF, and IGF, respectively. PDGF-AB and VEGF were essentially completely removed by the charcoal treatment. Mean albumin, immunoglobulins G, M and A, and fibrinogen content was about 40.0, 8.5, 0.87, 1.66 and 2.65 mg/mL, respectively, cholesterol and triglyceride 15 and 20.7 mg/mL, respectively, and TnBP and Triton X-45, 8.7 and 8.8 ppm, respectively. Supplementing MEM medium with 1-10% of this S/D-treated platelet lysate promoted the proliferation of MG63 and SIRC cell lines as well as, or better than, 10% FBS, as based on the MTS assay. The process used to prepare such S/D-treated platelet lysate is easily scalable for industrial production. Our results open the possibility to evaluate the interest of this new preparation for stem cell expansion and/or bone tissue engineering and regeneration. PMID: 20608898 [PubMed - as supplied by publisher] | | |
| Clinical application of an acellular biologic scaffold for surgical repair of a large, traumatic quadriceps femoris muscle defect.
July 9, 2010 at 3:24 PM
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| | Clinical application of an acellular biologic scaffold for surgical repair of a large, traumatic quadriceps femoris muscle defect. Orthopedics. 2010;33(7): Authors: Mase VJ, Hsu JR, Wolf SE, Wenke JC, Baer DG, Owens J, Badylak SF, Walters TJ Many battlefield injuries involve penetrating soft tissue trauma often accompanied by skeletal muscle defects, known as volumetric muscle loss. This article presents the first known case of a surgical technique involving an innovative tissue engineering approach for the repair of a large volumetric muscle loss.A 19-year-old Marine presented with large volumentric muscle loss of the right thigh as a result of an explosion. The patient reported muscle weakness with right knee extension, secondary to volumentric muscle loss, primarily involving the vastus medialis muscle. This persisted 3 years postinjury, despite extensive physical therapy. With all existing management options exhausted, restoration of a portion of the lost vastus medialis muscle was attempted by surgical implantation of a multi-layered scaffold composed of extracellular matrix derived from porcine intestinal submucossa. The patient had no complications, was discharged home on postoperative day 5, and resumed physical therapy after 4 weeks. Four months postoperatively, the patient demonstrated marked gains in isokinetic performance. Computer tomography indicated new tissue at the implant site.This approach offers a treatment option to a heretofore untreatable injury and will allow us to improve future surgical treatments for volumetric muscle loss. PMID: 20608620 [PubMed - in process] | | |
| The wrong emperor.
July 9, 2010 at 3:24 PM
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| | The wrong emperor. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Mar;109(3):327-8; author reply 328 Authors: Hargreaves KM, Law A PMID: 20219596 [PubMed - indexed for MEDLINE] | | |
| Thick soft tissue reconstruction on highly perfusive biodegradable scaffolds.
July 9, 2010 at 3:24 PM
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| | Thick soft tissue reconstruction on highly perfusive biodegradable scaffolds. Macromol Biosci. 2010 Feb 11;10(2):127-38 Authors: Mandoli C, Mecheri B, Forte G, Pagliari F, Pagliari S, Carotenuto F, Fiaccavento R, Rinaldi A, Di Nardo P, Licoccia S, Traversa E The lack of a vascular network and poor perfusion is what mostly prevents three-dimensional (3D) scaffolds from being used in organ repair when reconstruction of thick tissues is needed. Highly-porous scaffolds made of poly(L-lactic acid) (PLLA) are prepared by directional thermally induced phase separation (dTIPS) starting from 1,4-dioxane/PLLA solutions. The influence of polymer concentration and temperature gradient, in terms of imposed intensity and direction, on pore size and distribution is studied by comparison with scaffolds prepared by isotropic TIPS. The processing parameters are optimized to achieve an overall porosity for the 3D scaffolds of about 93% with a degree of interconnectivity of 91%. The resulting pore network is characterized by the ordered repetition of closely packed dendrite-like cavities, each one showing stacks of 20 microm large side lamellar branches departing from 70 microm diameter vertical backbones, strongly resembling the vascular patterns. The in vitro biological responses after 1 and 2 weeks are evaluated from mesenchymal (bone marrow stromal) cells (MSC) static culturing. A novel vacuum-based deep-seeding method is set up to improve uniform cell penetration down to scaffold thicknesses of over 1 mm. Biological screenings show significant 3D scaffold colonization even after 18 h, while cellular retention is observed up to 14 d in vitro (DIV). Pore architecture-driven cellular growth is accompanied by cell tendency to preserve their multi-potency towards differentiation. Confluent tissues as thick as 1 mm were reconstructed taking advantage of the large perfusion enhanced by the highly porous microstructure of the engineered scaffolds, which could successfully serve for applications aimed at vascular nets and angiogenesis. PMID: 19890887 [PubMed - indexed for MEDLINE] | | |
| In vitro evaluation of the bioactive factors preserved in porcine small intestinal submucosa through cellular biological approaches.
July 9, 2010 at 3:24 PM
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| | In vitro evaluation of the bioactive factors preserved in porcine small intestinal submucosa through cellular biological approaches. J Biomed Mater Res A. 2010 Jun 1;93(3):1100-9 Authors: Yang B, Zhou L, Sun Z, Yang R, Chen Y, Dai Y The objective of this study was to develop cellular biological approaches to evaluate the potential effect of bioactive factors in porcine small intestinal submucosa (SIS) on bladder regeneration and angiogenesis. For this purpose, we cultured human bladder smooth muscle cell (HBSMC) and human umbilical vein endothelial cell (HUVEC), and then used cellular biological techniques to characterize in vitro biological effect of SIS components on HBSMC and HUVEC. Our results indicated that the SIS components had stimulated the attachment, proliferation, and migration of HBSMC and HUVEC, as well as tube formation by HUVEC on Matrigel. These results implied that the SIS might have preserved a mixture of bioactive factors including cell adhesion factors, mitogenic factors, chemotactic cytokines, and angiogenic factors, and these bioactive factors would have the potential of promoting bladder regeneration and angiogenesis. In conclusion, these cellular biological approaches might be helpful and effective for evaluation of the bioactive factors preserved in porcine SIS before it is used for bladder augmentation in humans. PMID: 19768788 [PubMed - indexed for MEDLINE] | | |
| Elucidating Mechanisms of Osteogenesis in Human Adipose-Derived Stromal Cells via Microarray Analysis.
July 9, 2010 at 2:47 PM
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| | Elucidating Mechanisms of Osteogenesis in Human Adipose-Derived Stromal Cells via Microarray Analysis. J Craniofac Surg. 2010 Jul 2; Authors: Lee J, Gupta D, Panetta NJ, Levi B, James AW, Wan D, Commons GW, Longaker MT INTRODUCTION:: The osteogenic potential of human adipose-derived stromal cells (hASCs), the ease of cell procurement, and the shortcomings of conventional skeletal reconstruction call for further analysis of the molecular mechanisms governing hASC osteogenic differentiation. We have examined the expression profile of the human transcriptome during osteogenic differentiation of ASCs using microarray. Subsequently, we analyzed those genes related to osteogenesis that have not been previously studied about hASCs. We have preliminarily assessed the role of IGFBP3, TGF-B3, TNC, CTGF, DKK-1, and PDGFRB in hASC osteogenic differentiation. METHODS:: We compared the expression profile of undifferentiated hASCs to that of hASCs treated with osteogenic differentiation medium for 1, 3, or 7 days using the Human Exonic Evidence-Based Oligonucleotide chip. Genes significantly overexpress or underexpressed were validated with quantitative reverse transcription-polymerase chain reaction. The osteogenic capability of ASCs was verified by Alizarin Red staining. RESULTS:: IGFBP3, TGF-B3, TNC, CTGF, and PDGFRB were all upregulated in early osteogenesis, and TGF-B3, TNC, and PDGFRB were upregulated in late osteogenesis by microarray and quantitative reverse transcription analysis. In contrast, DKK-1 was downregulated in early and late osteogenesis. Alizarin Red staining showed a significant increase in mineralization in hASCs, even after 1 day in osteogenic differentiation medium. CONCLUSIONS:: Factors that commit hASCs to an osteogenic pathway remain largely unknown. We have described 6 genes that play key roles in hASC osteogenic differentiation. We plan to further exploit these data via in vitro treatment of hASCs with these soluble cytokines and in vivo translation using a nude mouse calvarial defect model. PMID: 20613589 [PubMed - as supplied by publisher] | | |
| Fabrication and characterization of an inorganic gold and silica nanoparticle mediated drug delivery system for nitric oxide.
July 9, 2010 at 2:47 PM
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| | Fabrication and characterization of an inorganic gold and silica nanoparticle mediated drug delivery system for nitric oxide. Nanotechnology. 2010 Jul 8;21(30):305102 Authors: Das A, Mukherjee P, Singla SK, Guturu P, Frost MC, Mukhopadhyay D, Shah VH, Patra CR Nitric oxide (NO) plays an important role in inhibiting the development of hepatic fibrosis and its ensuing complication of portal hypertension by inhibiting human hepatic stellate cell (HSC) activation. Here we have developed a gold nanoparticle and silica nanoparticle mediated drug delivery system containing NO donors, which could be used for potential therapeutic application in chronic liver disease. The gold nanoconjugates were characterized using several physico-chemical techniques such as UV-visible spectroscopy and transmission electron microscopy. Silica nanoconjugates were synthesized and characterized as reported previously. NO released from gold and silica nanoconjugates was quantified under physiological conditions (pH = 7.4 at 37 degrees C) for a substantial period of time. HSC proliferation and the vascular tube formation ability, manifestations of their activation, were significantly attenuated by the NO released from these nanoconjugates. This study indicates that gold and silica nanoparticle mediated drug delivery systems for introducing NO could be used as a strategy for the treatment of hepatic fibrosis or chronic liver diseases, by limiting HSC activation. PMID: 20610873 [PubMed - as supplied by publisher] | | |
| A recessive screen for genes regulating hematopoietic stem cells.
July 9, 2010 at 2:47 PM
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| | A recessive screen for genes regulating hematopoietic stem cells. Blood. 2010 Jul 7; Authors: Papathanasiou P, Tunningley R, Pattabiraman DR, Ye P, Gonda TJ, Whittle B, Hamilton AE, Cridland SO, Lourie R, Perkins AC Identification of genes that regulate the development, self-renewal and differentiation of stem cells is of vital importance for understanding normal organogenesis and cancer; such knowledge also underpins regenerative medicine. Here we demonstrate that chemical mutagenesis of mice combined with advances in hematopoietic stem cell reagents and genome resources can efficiently recover recessive mutations and identify genes essential for generation and proliferation of definitive hematopoietic stem cells and/or their progeny. We employed high-throughput FACS to analyze nine subsets of blood stem cells, progenitor cells, circulating red cells and platelets in >1,300 mouse embryos at embryonic day (E) 14.5. From 45 pedigrees we recovered six strains with defects in definitive hematopoiesis. We demonstrate rapid identification of a novel mutation in the c-Myb transcription factor that results in thrombocythemia and myelofibrosis as proof-of-principal of the utility of our FACS-based screen. Such phenotype-driven approaches will provide new knowledge of genes, protein interactions and regulatory networks which underpin stem cell biology. PMID: 20610815 [PubMed - as supplied by publisher] | | |
| Ethanol Alters the Osteogenic Differentiation of Amniotic Fluid-Derived Stem Cells.
July 9, 2010 at 2:47 PM
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| | Ethanol Alters the Osteogenic Differentiation of Amniotic Fluid-Derived Stem Cells. Alcohol Clin Exp Res. 2010 Jul 5; Authors: Hipp JA, Hipp JD, Atala A, Soker S Background: Fetal alcohol spectrum disorder (FASD) is a set of developmental defects caused by prenatal alcohol exposure. Clinical manifestations of FASD are highly variable and include mental retardation and developmental defects of the heart, kidney, muscle, skeleton, and craniofacial structures. Specific effects of ethanol on fetal cells include induction of apoptosis as well as inhibition of proliferation, differentiation, and migration. This complex set of responses suggests that a bioinformatics approach could clarify some of the pathways involved in these responses. Methods: In this study, the responses of fetal stem cells derived from the amniotic fluid (AFSCs) to treatment with ethanol have been examined. Large-scale transcriptome analysis of ethanol-treated AFSCs indicates that genes involved in skeletal development and ossification are up-regulated in these cells. Therefore, the effect of ethanol on osteogenic differentiation of AFSCs was studied. Results: Exposure to ethanol during the first 48 hours of an osteogenic differentiation protocol increased in vitro calcium deposition by AFSCs and increased alkaline phosphatase activity. In contrast, ethanol treatment later in the differentiation protocol (day 8) had no significant effect on the activity of alkaline phosphatase. Conclusions: These results suggest that transient exposure of AFSCs to ethanol during early differentiation enhances osteogenic differentiation of the cells. PMID: 20608908 [PubMed - as supplied by publisher] | | |
| Characterization of adipocyte differentiation from human mesenchymal stem cells in bone marrow.
July 9, 2010 at 2:47 PM
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| | Characterization of adipocyte differentiation from human mesenchymal stem cells in bone marrow. BMC Dev Biol. 2010;10:47 Authors: Qian SW, Li X, Zhang YY, Huang HY, Liu Y, Sun X, Tang QQ BACKGROUND: Adipocyte hyperplasia is associated with obesity and arises due to adipogenic differentiation of resident multipotent stem cells in the vascular stroma of adipose tissue and remote stem cells of other organs. The mechanistic characterization of adipocyte differentiation has been researched in murine pre-adipocyte models (i.e. 3T3-L1 and 3T3-F442A), revealing that growth-arrest pre-adipocytes undergo mitotic clonal expansion and that regulation of the differentiation process relies on the sequential expression of three key transcription factors (C/EBPbeta, C/EBPalpha and PPARgamma). However, the mechanisms underlying adipocyte differentiation from multipotent stem cells, particularly human mesenchymal stem cells (hBMSCs), remain poorly understood. This study investigated cell cycle regulation and the roles of C/EBPbeta, C/EBPalpha and PPARgamma during adipocyte differentiation from hBMSCs. RESULTS: Utilising a BrdU incorporation assay and manual cell counting it was demonstrated that induction of adipocyte differentiation in culture resulted in 3T3-L1 pre-adipocytes but not hBMSCs undergoing mitotic clonal expansion. Knock-down and over-expression assays revealed that C/EBPbeta, C/EBPalpha and PPARgamma were required for adipocyte differentiation from hBMSCs. C/EBPbeta and C/EBPalpha individually induced adipocyte differentiation in the presence of inducers; PPARgamma alone initiated adipocyte differentiation but the cells failed to differentiate fully. Therefore, the roles of these transcription factors during human adipocyte differentiation are different from their respective roles in mouse. CONCLUSIONS: The characteristics of hBMSCs during adipogenic differentiation are different from those of murine cells. These findings could be important in elucidating the mechanisms underlying human obesity further. PMID: 20459638 [PubMed - indexed for MEDLINE] | | |
| Comparison of defined culture systems for feeder cell free propagation of human embryonic stem cells.
July 9, 2010 at 2:47 PM
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| | Comparison of defined culture systems for feeder cell free propagation of human embryonic stem cells. In Vitro Cell Dev Biol Anim. 2010 Apr;46(3-4):247-58 Authors: , Akopian V, Andrews PW, Beil S, Benvenisty N, Brehm J, Christie M, Ford A, Fox V, Gokhale PJ, Healy L, Holm F, Hovatta O, Knowles BB, Ludwig TE, McKay RD, Miyazaki T, Nakatsuji N, Oh SK, Pera MF, Rossant J, Stacey GN, Suemori H There are many reports of defined culture systems for the propagation of human embryonic stem cells in the absence of feeder cell support, but no previous study has undertaken a multi-laboratory comparison of these diverse methodologies. In this study, five separate laboratories, each with experience in human embryonic stem cell culture, used a panel of ten embryonic stem cell lines (including WA09 as an index cell line common to all laboratories) to assess eight cell culture methods, with propagation in the presence of Knockout Serum Replacer, FGF-2, and mouse embryonic fibroblast feeder cell layers serving as a positive control. The cultures were assessed for up to ten passages for attachment, death, and differentiated morphology by phase contrast microscopy, for growth by serial cell counts, and for maintenance of stem cell surface marker expression by flow cytometry. Of the eight culture systems, only the control and those based on two commercial media, mTeSR1 and STEMPRO, supported maintenance of most cell lines for ten passages. Cultures grown in the remaining media failed before this point due to lack of attachment, cell death, or overt cell differentiation. Possible explanations for relative success of the commercial formulations in this study, and the lack of success with other formulations from academic groups compared to previously published results, include: the complex combination of growth factors present in the commercial preparations; improved development, manufacture, and quality control in the commercial products; differences in epigenetic adaptation to culture in vitro between different ES cell lines grown in different laboratories. PMID: 20186512 [PubMed - indexed for MEDLINE] | | |
| Elucidating Mechanisms of Osteogenesis in Human Adipose-Derived Stromal Cells via Microarray Analysis.
July 9, 2010 at 2:16 PM
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| | Elucidating Mechanisms of Osteogenesis in Human Adipose-Derived Stromal Cells via Microarray Analysis. J Craniofac Surg. 2010 Jul 2; Authors: Lee J, Gupta D, Panetta NJ, Levi B, James AW, Wan D, Commons GW, Longaker MT INTRODUCTION:: The osteogenic potential of human adipose-derived stromal cells (hASCs), the ease of cell procurement, and the shortcomings of conventional skeletal reconstruction call for further analysis of the molecular mechanisms governing hASC osteogenic differentiation. We have examined the expression profile of the human transcriptome during osteogenic differentiation of ASCs using microarray. Subsequently, we analyzed those genes related to osteogenesis that have not been previously studied about hASCs. We have preliminarily assessed the role of IGFBP3, TGF-B3, TNC, CTGF, DKK-1, and PDGFRB in hASC osteogenic differentiation. METHODS:: We compared the expression profile of undifferentiated hASCs to that of hASCs treated with osteogenic differentiation medium for 1, 3, or 7 days using the Human Exonic Evidence-Based Oligonucleotide chip. Genes significantly overexpress or underexpressed were validated with quantitative reverse transcription-polymerase chain reaction. The osteogenic capability of ASCs was verified by Alizarin Red staining. RESULTS:: IGFBP3, TGF-B3, TNC, CTGF, and PDGFRB were all upregulated in early osteogenesis, and TGF-B3, TNC, and PDGFRB were upregulated in late osteogenesis by microarray and quantitative reverse transcription analysis. In contrast, DKK-1 was downregulated in early and late osteogenesis. Alizarin Red staining showed a significant increase in mineralization in hASCs, even after 1 day in osteogenic differentiation medium. CONCLUSIONS:: Factors that commit hASCs to an osteogenic pathway remain largely unknown. We have described 6 genes that play key roles in hASC osteogenic differentiation. We plan to further exploit these data via in vitro treatment of hASCs with these soluble cytokines and in vivo translation using a nude mouse calvarial defect model. PMID: 20613589 [PubMed - as supplied by publisher] | | |
| Characterization of adipocyte differentiation from human mesenchymal stem cells in bone marrow.
July 9, 2010 at 2:16 PM
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| | Characterization of adipocyte differentiation from human mesenchymal stem cells in bone marrow. BMC Dev Biol. 2010;10:47 Authors: Qian SW, Li X, Zhang YY, Huang HY, Liu Y, Sun X, Tang QQ BACKGROUND: Adipocyte hyperplasia is associated with obesity and arises due to adipogenic differentiation of resident multipotent stem cells in the vascular stroma of adipose tissue and remote stem cells of other organs. The mechanistic characterization of adipocyte differentiation has been researched in murine pre-adipocyte models (i.e. 3T3-L1 and 3T3-F442A), revealing that growth-arrest pre-adipocytes undergo mitotic clonal expansion and that regulation of the differentiation process relies on the sequential expression of three key transcription factors (C/EBPbeta, C/EBPalpha and PPARgamma). However, the mechanisms underlying adipocyte differentiation from multipotent stem cells, particularly human mesenchymal stem cells (hBMSCs), remain poorly understood. This study investigated cell cycle regulation and the roles of C/EBPbeta, C/EBPalpha and PPARgamma during adipocyte differentiation from hBMSCs. RESULTS: Utilising a BrdU incorporation assay and manual cell counting it was demonstrated that induction of adipocyte differentiation in culture resulted in 3T3-L1 pre-adipocytes but not hBMSCs undergoing mitotic clonal expansion. Knock-down and over-expression assays revealed that C/EBPbeta, C/EBPalpha and PPARgamma were required for adipocyte differentiation from hBMSCs. C/EBPbeta and C/EBPalpha individually induced adipocyte differentiation in the presence of inducers; PPARgamma alone initiated adipocyte differentiation but the cells failed to differentiate fully. Therefore, the roles of these transcription factors during human adipocyte differentiation are different from their respective roles in mouse. CONCLUSIONS: The characteristics of hBMSCs during adipogenic differentiation are different from those of murine cells. These findings could be important in elucidating the mechanisms underlying human obesity further. PMID: 20459638 [PubMed - indexed for MEDLINE] | | |
| Morphological changes in paraurethral area after introduction of tissue engineering construct on the basis of adipose tissue stromal cells.
July 9, 2010 at 2:16 PM
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| | Morphological changes in paraurethral area after introduction of tissue engineering construct on the basis of adipose tissue stromal cells. Bull Exp Biol Med. 2009 Oct;148(4):719-24 Authors: Makarov AV, Arutyunyan IV, Bol'shakova GB, Volkov AV, Gol'dshtein DV We studied morphological changes in the paraurethral area of Wistar rats after introduction of tissue engineering constructs on the basis of multipotent mesenchymal stem cells and gelatin sponge. The tissue engineering construct containing autologous culture of the stromal fraction of the adipose tissue was most effective. After introduction of this construct we observed more rapid degradation of the construct matrix and more intensive formation of collagen fibers. PMID: 20396777 [PubMed - indexed for MEDLINE] | | |
| Pdx1-transfected adipose tissue-derived stem cells differentiate into insulin-producing cells in vivo and reduce hyperglycemia in diabetic mice.
July 9, 2010 at 2:16 PM
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| | Pdx1-transfected adipose tissue-derived stem cells differentiate into insulin-producing cells in vivo and reduce hyperglycemia in diabetic mice. Int J Dev Biol. 2010;54(4):699-705 Authors: Kajiyama H, Hamazaki TS, Tokuhara M, Masui S, Okabayashi K, Ohnuma K, Yabe S, Yasuda K, Ishiura S, Okochi H, Asashima M Insulin-dependent diabetes mellitus (IDDM) is characterized by the rapid development of potentially severe metabolic abnormalities resulting from insulin deficiency. The transplantation of insulin-producing cells is a promising approach for the treatment of IDDM. The transcription factor pancreatic duodenal homeobox 1 (Pdx1) plays an important role in the differentiation of pancreatic beta cells. In this study, the human Pdx1 gene was transduced and expressed in murine adipose tissue-derived stem cells (ASCs). To evaluate pancreatic repair, we used a mouse model of pancreatic damage resulting in hyperglycemia, which involves injection of mice with streptozotocin (STZ). STZ-treated mice transplanted with Pdx1-transduced ASCs (Pdx1-ASCs) showed significantly decreased blood glucose levels and increased survival, when compared with control mice. While stable expression of Pdx1 in ASCs did not induce the pancreatic phenotype in vitro in our experiment, the transplanted stem cells became engrafted in the pancreas, wherein they expressed insulin and C-peptide, which is a marker of insulin-producing cells. These results suggest that Pdx1-ASCs are stably engrafted in the pancreas, acquire a functional beta-cell phenotype, and partially restore pancreatic function in vivo. The ease and safety associated with extirpating high numbers of cells from adipose tissues support the applicability of this system to developing a new cell therapy for IDDM. PMID: 19757377 [PubMed - indexed for MEDLINE] | | |
| SF Lawyer Urges Openness at Stem Cell Agency
July 9, 2010 at 8:09 AM
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| Writing in connection with an incident in which two persons were barred from a CIRM meeting, a San Francisco attorney this week called on the California stem cell agency "to return to its commitment to an open and public process."
Justine Durrell, who is involved in issues dealing with biotech and women's health, made the comment in a three-page letter to the 29 members of the board of | | | | 
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