| Maintenance of pluripotency in human embryonic stem cells cultured on a synthetic substrate in conditioned medium.
September 1, 2009 at 6:11 am
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| | Maintenance of pluripotency in human embryonic stem cells cultured on a synthetic substrate in conditioned medium. Biotechnol Bioeng. 2009 Aug 28; Authors: Mahlstedt MM, Anderson D, Sharp JS, McGilvray R, Muñoz MD, Buttery LD, Alexander MR, Rose FR, Denning C Realising the potential clinical and industrial applications of human embryonic stem cells (hESCs) is limited by the need for costly, labile or undefined growth substrates. Here we demonstrate that trypsin-passaging of the hESC lines, HUES7 and NOTT1, on oxygen plasma etched tissue culture polystyrene (PE-TCPS) in conditioned medium is compatible with pluripotency. This synthetic culture surface is stable at room temperature for at least a year and is readily prepared by placing polystyrene substrates in a radio frequency oxygen plasma generator for 5 minutes. Modification of the polystyrene surface chemistry by plasma etching was confirmed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS), which identified elemental and molecular changes as a result of the treatment. Pluripotency of hESCs cultured on PE-TCPS was gauged by consistent proliferation during serial passage, expression of stem cell markers (OCT4, TRA1-60 and SSEA-4), stable karyotype and multi-germlayer differentiation in vitro, including to pharmacologically responsive cardiomyocytes. Generation of cost-effective, easy-to-handle synthetic, defined, stable surfaces for hESC culture will expedite stem cell use in biomedical applications. (c) 2009 Wiley Periodicals, Inc. PMID: 19718698 [PubMed - as supplied by publisher] |
| Optical manipulation for single-cell studies.
September 1, 2009 at 6:11 am
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| | Optical manipulation for single-cell studies. J Biophotonics. 2009 Aug 28; Authors: Ramser K, Hanstorp D In the last decade optical manipulation has evolved from a field of interest for physicists to a versatile tool widely used within life sciences. This has been made possible in particular due to the development of a large variety of imaging techniques that allow detailed information to be gained from investigations of single cells. The use of multiple optical traps has high potential within single-cell analysis since parallel measurements provide good statistics. Multifunctional optical tweezers are, for instance, used to study cell heterogeneity in an ensemble, and force measurements are used to investigate the mechanical properties of individual cells. Investigations of molecular motors and forces on the single-molecule level have led to discoveries that would have been difficult to make with other techniques. Optical manipulation has prospects within the field of cell signalling and tissue engineering. When combined with microfluidic systems the chemical environment of cells can be precisely controlled. Hence the influence of pH, salt concentration, drugs and temperature can be investigated in real time. Fast advancing technical developments of automated and user-friendly optical manipulation tools and cross-disciplinary collaboration will contribute to the routinely use of optical manipulation techniques within the life sciences. ((c) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim). PMID: 19718682 [PubMed - as supplied by publisher] |
| Tcf3 and Tcf4 are essential for long-term homeostasis of skin epithelia.
September 1, 2009 at 6:11 am
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| | Tcf3 and Tcf4 are essential for long-term homeostasis of skin epithelia. Nat Genet. 2009 Aug 30; Authors: Nguyen H, Merrill BJ, Polak L, Nikolova M, Rendl M, Shaver TM, Pasolli HA, Fuchs E Single-layered embryonic skin either stratifies to form epidermis or responds to Wnt signaling (stabilized beta-catenin) to form hair follicles. Postnatally, stem cells continue to differentially use Wnt signaling in long-term tissue homeostasis. We have discovered that embryonic progenitor cells and postnatal hair follicle stem cells coexpress Tcf3 and Tcf4, which can act as transcriptional activators or repressors. Using loss-of-function studies and transcriptional analyses, we uncovered consequences to the absence of Tcf3 and Tcf4 in skin that only partially overlap with those caused by beta-catenin deficiency. We established roles for Tcf3 and Tcf4 in long-term maintenance and wound repair of both epidermis and hair follicles, suggesting that Tcf proteins have both Wnt-dependent and Wnt-independent roles in lineage determination. PMID: 19718027 [PubMed - as supplied by publisher] |
| Bone marrow stem and progenitor cell contribution to neovasculogenesis is dependent on model system with SDF-1 as a permissive trigger.
September 1, 2009 at 6:11 am
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| | Bone marrow stem and progenitor cell contribution to neovasculogenesis is dependent on model system with SDF-1 as a permissive trigger. Blood. 2009 Aug 28; Authors: Madlambayan GJ, Butler JM, Hosaka K, Jorgensen M, Fu D, Guthrie SM, Shenoy AK, Brank A, Russell KJ, Otero J, Siemann DW, Scott EW, Cogle CR Adult bone marrow (BM) contributes to neovascularization in some but not all settings, and reasons for these discordant results have remained unexplored. We conducted novel comparative studies in which multiple neovascularization models were established in single mice to reduce variations in experimental methodology. In different combinations, BM contribution was detected in ischemic retinas and, to a lesser extent, Lewis lung carcinomas (LLC); while B16 melanomas showed little to no BM contribution. Using this spectrum of BM contribution, we demonstrate the necessity for site-specific expression of SDF-1alpha and its mobilizing effects on BM. Blocking SDF-1alpha activity with neutralizing antibodies abrogated BM-derived neovascularization in lung cancer and retinopathy. Furthermore, secondary transplantation of single hematopoietic stem cells (HSCs) showed that HSCs are a long-term source of neovasculogenesis and that CD133(+)CXCR4(+) myeloid progenitor cells directly participate in new blood vessel formation in response to SDF-1alpha. The varied BM contribution seen in different model systems is suggestive of redundant mechanisms governing post-natal neovasculogenesis and provides an explanation for contradictory results observed in the field. PMID: 19717647 [PubMed - as supplied by publisher] |
| Epigenetic Silencing of Stk39 in B-Cell Lymphoma Inhibits Apoptosis from Genotoxic Stress.
September 1, 2009 at 6:11 am
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| | Epigenetic Silencing of Stk39 in B-Cell Lymphoma Inhibits Apoptosis from Genotoxic Stress. Am J Pathol. 2009 Aug 28; Authors: Balatoni CE, Dawson DW, Suh J, Sherman MH, Sanders G, Hong JS, Frank MJ, Malone CS, Said JW, Teitell MA B-cell lymphomas, the most frequent human immune system malignancies, often contain dysregulated TCL1 oncogene expression. TCL1 transgenic (TCL1-tg) mice develop a spectrum of B-cell malignancies, supporting an oncogenic role for TCL1 in B cells. Our prior global survey of DNA methylation patterns in TCL1-tg B-cell lymphomas identified many lymphoma-specific candidate hypermethylated genes, including Stk39. The Stk39 encoded protein, sterile 20-like-related proline-alanine-rich kinase (SPAK), regulates cell stress responses, and microarray studies identified reduced SPAK expression in metastatic prostate and treatment-resistant breast cancers, suggesting that its loss may have a role in cancer progression. Here we identified DNA hypermethylation and SPAK silencing in TCL1-tg B-cell lymphomas and SPAK silencing without DNA methylation in multiple subtypes of human B-cell lymphomas. SPAK knockdown by shRNA protected B cells from caspase-dependent apoptosis induced by DNA double-strand breaks but not apoptosis in response to osmotic or oxidative cell stressors. Caspase 3 activation by cleavage was impaired with SPAK repression in DNA damaged B cells. Interestingly, c-Jun NH2-terminal kinase is potentially activated by SPAK and pharmacological inhibition of c-Jun NH2-terminal kinase in SPAK-expressing B cells recapitulated the cell-protective phenotype of SPAK knockdown. Taken together, these data indicate that SPAK loss in B-cell lymphomas promotes increased cell survival with DNA damage and provides a potential mechanism for increased resistance to genotoxic stress in cancer. PMID: 19717643 [PubMed - as supplied by publisher] |
| Transforming growth factors {beta} (TGF{beta}S) coordinate cartilage and tendon differentiation in the developing limb mesenchyme.
September 1, 2009 at 6:11 am
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| | Transforming growth factors {beta} (TGF{beta}S) coordinate cartilage and tendon differentiation in the developing limb mesenchyme. J Biol Chem. 2009 Aug 28; Authors: Lorda-Diez CI, Montero JA, Martinez-Cue C, Garcia-Porrero JA, Hurle JM Transforming growth factor beta (Tgfbeta) signaling has an increasing interest in regenerative medicine as a potential tool to repair cartilages, however the chondrogenic effect of this pathway in developing systems is controversial. Here we have analyzed the function of Tgfbeta signaling in the differentiation of the developing limb mesoderm in vivo and in high-density micromass cultures. In these systems highest signaling activity corresponded with cells at stages preceding overt chondrocyte differentiation. Interestingly treatments with Tgfbetas shifted the differentiation outcome of the cultures from chondrogenesis to fibrogenesis. This phenotypic reprogramming involved downregulation of Sox9 and Aggrecan and upregulation of Scleraxis, and Tenomodulin through the Smad pathway. We further show that Tgfbeta signaling up-regulates Sox9 in the in vivo experimental model system in which Tgfbeta treatments induce ectopic chondrogenesis. Looking for clues explaining the dual role of Tgfbeta signaling, we found that Tgf?s appear to be direct inducers of the chondrogenic gene Sox9, but the existence of transcriptional repressors of Tgfbeta signaling modulates this role. We identified TG-interacting factor Tgif1 and SKI-like oncogene SnoN as potential candidates for this inhibitory function. Tgif1 gene regulation by Tgfbeta signaling correlated with the differential chondrogenic and fibrogenic effects of this pathway and its expression pattern in the limb marks the developing tendons. In functional experiments we found that Tgif1 reproduces the profibrogenic effect of Tgfbeta treatments. PMID: 19717568 [PubMed - as supplied by publisher] |
| Patterning of biomolecules on a poly(varepsilon-caprolactone) film surface functionalized by ion implantation.
September 1, 2009 at 6:11 am
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| | Patterning of biomolecules on a poly(varepsilon-caprolactone) film surface functionalized by ion implantation. Colloids Surf B Biointerfaces. 2009 Aug 12; Authors: Hwang IT, Jung CH, Kim DK, Nho YC, Choi JH Biomolecule patterning is important due to its potential applications in biodevices, tissue engineering, and drug delivery. In this study, we developed a new method for a biomolecular patterning on poly(varepsilon-caprolactone) (PCL) films based on ion implantation. Ion implantation on a PCL film surface resulted in the formation of carboxylic acid groups. The generated carboxylic acid groups were used for the covalent immobilization of amine-functionalized p-DNA, followed by hybridization with fluorescently tagged c-DNA. Biotin-amine was also covalently immobilized on the carboxylic acid generated PCL surfaces. Successful biotin-specific binding of streptavidin further confirmed the potential of this strategy for patterning of various biomolecules. PMID: 19717288 [PubMed - as supplied by publisher] |
| Histone deacetylase 4 promotes TGF-beta1-induced synovium-derived stem cell chondrogenesis but inhibits chondrogenically differentiated stem cell hypertrophy.
September 1, 2009 at 6:11 am
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| | Histone deacetylase 4 promotes TGF-beta1-induced synovium-derived stem cell chondrogenesis but inhibits chondrogenically differentiated stem cell hypertrophy. Differentiation. 2009 Aug 27; Authors: Pei M, Chen D, Li J, Wei L The transforming growth factor-beta (TGF-beta) superfamily members play diverse roles in cartilage development and maintenance. TGF-beta up-regulates chondrogenic gene expression by enhancing transcription factor SRY (sex determining region Y)-box 9 (Sox9) and inhibits osteoblast differentiation by repressing runt-related transcription factor 2 (Runx2). Recently, histone deacetylases (HDACs) were reported to act as negative regulators of chondrocyte hypertrophy. It was speculated that HDAC4 may promote TGF-beta1-induced MSC chondrogenesis. In this study, the adenovirus-mediated HDAC4 gene (Ad.HDAC4) was utilized to infect synovium-derived stem cells (SDSCs). Adenovirus-mediated LacZ (Ad.LacZ) served as a control. The infected cells were centrifuged to form SDSC pellets followed by incubation in a serum-free chondrogenic medium for 15 days with or without 10ng/mL TGF-beta1. Transfection efficiency was determined in SDSCs using Ad.LacZ. Cytotoxicity was measured using lactate dehydrogenase assay. Histology, immunostaining, biochemical analysis, and real-time polymerase chain reaction were performed to assess chondrogenesis at protein and mRNA levels in infected SDSCs. Our data demonstrated that supplementation with TGF-beta1 could initiate and promote SDSC chondrogenesis; however, TGF-beta1 alone was insufficient to fully differentiate SDSCs into chondrocytes. Ad.HDAC4 could be efficiently transfected into SDSCs. Without TGF-beta1 treatment, HDAC4 had no effect on SDSC chondrogenesis; however, in the presence of TGF-beta1, HDAC4 could speed up and maintain a high level of chondrogenesis while down-regulating the hypertrophic marker - type X collagen expression. This study is the first report showing that HDAC4 overexpression promotes TGF-beta1-induced SDSC chondrogenesis but inhibits chondrogenically differentiated stem cell hypertrophy. The mechanism underlying this process needs further investigation. PMID: 19716643 [PubMed - as supplied by publisher] |
| Recent developments in processing systems for cell and tissue cultures toward therapeutic application.
September 1, 2009 at 6:11 am
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| | Recent developments in processing systems for cell and tissue cultures toward therapeutic application. J Biosci Bioeng. 2009 Oct;108(4):267-76 Authors: Kino-oka M, Taya M Innovative techniques of cell and tissue processing, based on tissue engineering, have been developed for therapeutic applications. Cell expansion and tissue reconstruction through ex vivo cultures are core processes used to produce engineered tissues with sufficient structural integrity and functionality. In manufacturing, strict management against contamination and human error is compelled due to direct use of un-sterilable products and the laboriousness of culture operations, respectively. Therefore, the development of processing systems for cell and tissue cultures is one of the critical issues for ensuring a stable process and quality of therapeutic products. However, the siting criterion of culture systems to date has not been made clear. This review article classifies some of the known processing systems into 'sealed-chamber' and 'sealed-vessel' culture systems based on the difference in their aseptic spaces, and describes the potential advantages of these systems and current states of culture systems, especially those established by Japanese companies. Moreover, on the basis of the guidelines for isolator systems used in aseptic processing for healthcare products, which are issued by the International Organization for Standardization, the siting criterion of the processing systems for cells and tissue cultures is discussed in perspective of manufacturing therapeutic products in consideration of the regulations according to the Good Manufacturing Practice. PMID: 19716513 [PubMed - in process] |
| Cell sheet transplantation of cultured mesenchymal stem cells enhances bone formation in a rat nonunion model.
September 1, 2009 at 6:11 am
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| | Cell sheet transplantation of cultured mesenchymal stem cells enhances bone formation in a rat nonunion model. Bone. 2009 Aug 26; Authors: Nakamura A, Akahane M, Shigematsu H, Tadokoro M, Ohgushi H, Dohi Y, Imamura T, Tanaka Y Orthopedic surgeons have long been troubled by cases involving nonunion of fractured bones. This study aimed to enhance bone union by cell sheet transplantation of mesenchymal stem cells. A nonunion model was made in rat femur, and rat bone marrow cells were cultured in medium containing dexamethasone and ascorbic acid phosphate to create a cell sheet that could be scraped off as a single sheet. Cell sheets were transplanted onto fractured femurs without a scaffold in the model. X-ray and histological analysis were performed at 2, 4 and 8 weeks. Ultrasonography and biomechanical analysis were performed at 8 weeks. X-ray photographs and histological sections showed callus formation around the fracture site in the cell sheet-transplanted group (sheet group). Bone union was obtained in the sheet group at 8 weeks. By contrast, the control group (without sheet transplantation) showed nonunion of the femur. The results of pullout evaluation in the vertical direction of the femur in the sheet group were significantly better than that of the control group. Analysis of the origin of de novo formed bone using the Sry gene, which was used as a marker for donor cells, showed that transplanted cells without scaffolds could survive and differentiate into osteogenic lineage cells in vivo. These results showed that the femoral fracture in our model was completely cured by the transplantation of a cell sheet created by tissue engineering techniques. Thus, we think that cell sheet transplantation can contribute to hard tissue reconstruction in cases involving nonunion, bone defects and osteonecrosis. PMID: 19716454 [PubMed - as supplied by publisher] |
| Biospinning by silkworms: Silk fiber matrices for tissue engineering applications.
September 1, 2009 at 6:11 am
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| | Biospinning by silkworms: Silk fiber matrices for tissue engineering applications. Acta Biomater. 2009 Aug 26; Authors: Mandal BB, Kundu SC Bio-spinning mechanism of natural silk fiber is an open issue since decades. In this report, bio-spun silk fiber based natural bio-polymeric matrix obtained from Antheraea mylitta a wild non-mulberry tropical tasar silkworm is projected for potential applications. This report deals with conformational transition of silk fibroin during bio-spinning process and its potential to support cell adherence and proliferation. The silk fibers obtained were aligned into linear, mixed and random patterns forming interconnected, macroporous 3D matrices. The matrices are morphologically and functionally characterized with respect to fiber diameter, crystallinity, mechanical strength and bio-compatibility using feline fibroblast cells. Drawn silk fibers showed enhanced stability to protease treatment in comparison to naturally occurring native gland fibroin protein. Live dead assay suggested bio-compatibility of these matrices in vitro. Fluorescence and confocal microscopy indicate normal cell attachment, spreading and proliferation on these biospun silk matrices. The results provide evidence for the use of biospun silk matrices as natural, inexpensive and alternative substratum for tissue engineering applications. PMID: 19716447 [PubMed - as supplied by publisher] |
| Increased mucociliary differentiation of human respiratory epithelial cells on hyaluronan derivative membranes.
September 1, 2009 at 6:11 am
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| | Increased mucociliary differentiation of human respiratory epithelial cells on hyaluronan derivative membranes. Acta Biomater. 2009 Aug 26; Authors: Huang TW, Chan YH, Cheng PW, Young YH, Lou PJ, Young TH The selection of scaffold facilitating mucociliary differentiation of respiratory epithelial cells (RECs) is crucial in the development of tissue engineering of respiratory epithelium. However, how the differentiation of RECs is influenced by the biomaterials has never been thoroughly explored. Previously, hyaluronan derivatives were considered as unsuitable biomaterials for culture of respiratory epithelium. In contrast, this study demonstrated that the membranous scaffolds made from benzyl esters of hyaluronic acids (HYAFF(TM)) were capable of providing a more preferential environment for human RECs than conventionally used collagen-based scaffolds. The proliferation and mucociliary differentiation of RECs were examined by MTT assays, scanning electron microscope, immunofluorescence, immunoblotting and gene expression. The percentage of ciliated cells in cultured RECs increased from 12.4% on collagen to 20.4% on hyaluronan derivative membranes with a pseudostratified polarized layer that closely resembled the composition of the native epithelium. The expression levels of MUC5AC and MUC5B mRNA were higher on hyaluronan-based scaffolds than those on collagen. The presence of hyaluronan binding domain, CD44 and receptor for hyaluronan-mediated motility (RHAMM), of RECs were also demonstrated. Accordingly, the mucociliary differentiation-promoting effect of hyaluronan derivative membranes indicates that it may be applied to the tissue engineering of respiratory epithelium. PMID: 19716445 [PubMed - as supplied by publisher] |
| Isolation and in vitro cultivation turns cells from exocrine human pancreas into multipotent stem-cells.
September 1, 2009 at 6:11 am
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| | Isolation and in vitro cultivation turns cells from exocrine human pancreas into multipotent stem-cells. Ann Anat. 2009 Jul 21; Authors: Rapoport DH, Schicktanz S, Gürleyik E, Zühlke C, Kruse C Several research groups have reported on the existence and in vitro characterization of multipotent stem-cells from the pancreas. However, the origin of these cells remains largely unexplained. Here, we report that in vitro culturing itself can turn adult cells from human exocrine pancreas into a cell population with typical stem cell characteristics. A simple, yet reliable method enabled us to track cell fates: Combining automated continuous observation using time-lapse microscopy with immunocytochemical analyses, we found that a significant fraction of the pancreatic cells ( approximately 14%) can survive trypsination and displays a drastic change in the protein expression profile. After further cultivation, these cells give rise to a heterogeneous cell population with typical multipotent stem cell characteristics; i.e. they proliferate over long time periods and continuously give rise to specialized cells from at least two germ layers. Although we cannot exclude that a rare pre-existing stem cell-type also contributes to the final in vitro-population, the majority of cells must have been arisen from mature pancreatic cells. Our findings indicate that multipotent cells for regenerative medicine, instead of being laboriously isolated, can be generated in large amounts by in vitro de-differentiation. PMID: 19716277 [PubMed - as supplied by publisher] |
| Analysis of different routes of administration of heterologous 5-azacytidine-treated mesenchymal stem cells in a porcine model of myocardial infarction.
September 1, 2009 at 6:11 am
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| | Analysis of different routes of administration of heterologous 5-azacytidine-treated mesenchymal stem cells in a porcine model of myocardial infarction. Transplant Proc. 2009 Jul-Aug;41(6):2273-5 Authors: Moscoso I, Barallobre J, de Ilarduya OM, Añón P, Fraga M, Calviño R, Aldama G, Doménech N Stem cell therapy constitutes an exciting, powerful therapy to repair the heart. Nevertheless, there are numerous doubts about the best route of stem cell administration to achieve implantation into the injured myocardium. Development of a preclinical, large animal model may be useful to obtain a better approach to clinical situations. The aim of this work was to study the effectiveness of various routes of heterologous bone marrow mesenchymal stem cell (MSCs) administration in a porcine model of myocardial infarction. MSC treated with 5-azacytidine were stained with a fluorescent compound (DiO) before their administration to previously infarcted pigs via 3 routes: intracoronary (IC), intramyocardial (IM), or endocardial (EC; n = 5 each group). Healthy, noninfarcted animals were used as a control group. At 30 days after delivery, hearts were divided into 12 parts: infarcted zone (1-6), right-left atria, interatrial and interventricular septa, and right-left ventricles. In each zone we looked for and quantified, injected fluorescence-stained cells. In the animals in which presence of DiO-stained cells was detected, cells were located preferentially in the infarcted zone and not in the atria, ventricles, or septa. Comparing various administration routes, the mean number of engrafted cells within the infarct zone was significantly greater after IC infusion than either IM or EC injection. Fluorescent cells were not observed in healthy zones of the myocardium or in healthy animals. PMID: 19715895 [PubMed - in process] |
| DNA methyltransferase inhibition induces mouse embryonic stem cell differentiation into endothelial cells.
September 1, 2009 at 6:11 am
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| | DNA methyltransferase inhibition induces mouse embryonic stem cell differentiation into endothelial cells. Exp Cell Res. 2009 Aug 25; Authors: Banerjee S, Bacanamwo M Understanding endothelial cell (EC) differentiation is a step forward in tissue engineering, controlling angiogenesis, and endothelial dysfunction. We hypothesized that epigenetic activation of EC lineage specification genes is an important mediator of embryonic stem cell (ESC) differentiation into EC. Mouse ESC was differentiated by removing leukemia inhibitory factor (LIF) from the maintenance media in the presence or absence of the specific DNA methyltransferase (DNMT) inhibitor 5'-aza-2'-deoxycytidine (aza-dC). Expression of EC specification and marker genes was monitored by quantitative PCR, western, immunocytochemistry, and flow cytometry. Functionality of differentiated EC was assessed by angiogenesis assay. The methylation status in the proximal promoter CpGs of the mediators of EC differentiation VEGF-A, BMP4, and EPAS-1 as well as of the mature EC marker VE-cadherin was determined by bisulfite sequencing. ESC differentiation resulted in repression of OCT4 expression in both the absence and presence of aza-dC treatment. However, significant increase in angiogenesis and expression of the mediators of EC differentiation and EC-specific genes was only observed in aza-dC-treated cells. The DNMT inhibition-mediated increase in EC specification and marker gene expression was not associated with demethylation of these genes. These studies suggest that DNMT inhibition is an efficient inducer of EC differentiation from ESC. PMID: 19715692 [PubMed - as supplied by publisher] |
| STEM CELL THERAPY FOR PARKINSON'S DISEASE: A ROAD MAP FOR A SUCCESSFUL FUTURE.
September 1, 2009 at 6:11 am
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| | STEM CELL THERAPY FOR PARKINSON'S DISEASE: A ROAD MAP FOR A SUCCESSFUL FUTURE. Stem Cells Dev. 2009 Aug 28; Authors: Vidaltamayo R, Bargas J, Covarrubias L, Hernández A, Galarraga E, Gutiérrez-Ospina G, Drucker-Colin R Cell transplant therapy for Parkinson's disease (PD) has been in use for over two decades as an experimental treatment. Different cell types have been proposed as better therapeutic alternatives. However, source availability and therapeutic value of the transplants as compared to current pharmacological options, has precluded the use of this kind of surgery in the majority of PD patients. In this paper, we discuss the suitability of different types of stem cells for PD therapy, the requirements that the donor cells should fulfill in order to improve upon current methods, and propose alternatives for evaluating the efficacy of PD cell therapy. PMID: 19715418 [PubMed - as supplied by publisher] |
| Chondrogenesis of adult stem cells from adipose tissue and bone marrow: Induction by growth factors and cartilage derived matrix.
September 1, 2009 at 6:11 am
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| | Chondrogenesis of adult stem cells from adipose tissue and bone marrow: Induction by growth factors and cartilage derived matrix. Tissue Eng Part A. 2009 Aug 28; Authors: Diekman BO, Rowland CR, Caplan AI, Lennon D, Guilak F Objectives: Adipose-derived stem cells (ASCs) and bone marrow-derived mesenchymal stem cells (MSCs) are multipotent adult stem cells with potential for use in cartilage tissue engineering. We hypothesized that these cells will show distinct responses to different chondrogenic culture conditions and extracellular matrices, illustrating important differences between cell types. Methods: Human ASCs and MSCs were chondrogenically differentiated in alginate beads or a novel scaffold of reconstituted native cartilage-derived matrix (CDM) with a range of growth factors including dexamethasone, transforming growth factor beta3 (TGF-beta3), and bone morphogenetic protein 6 (BMP-6). Constructs were analyzed for gene expression and matrix synthesis. Results: Chondrogenic growth factors induced a chondrocytic phenotype in both ASCs and MSCs in alginate beads or CDM. MSCs demonstrated enhanced type II collagen gene expression and matrix synthesis as well as a greater propensity for the hypertrophic chondrocyte phenotype. ASCs had higher upregulation of aggrecan gene expression in response to BMP-6 (857 fold), while MSCs responded more favorably to TGF-beta3 (573 fold increase). Conclusions: ASCs and MSCs are distinct cell types as illustrated by their unique responses to growth factor based chondrogenic induction. This chondrogenic induction is affected by the composition of the scaffold and the presence of serum. PMID: 19715387 [PubMed - as supplied by publisher] |
| Vascularized tissue-engineering mouse chamber model supports thymopoiesis of ectopic thymus tissue grafts.
September 1, 2009 at 6:11 am
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| | Vascularized tissue-engineering mouse chamber model supports thymopoiesis of ectopic thymus tissue grafts. Tissue Eng Part C Methods. 2009 Aug 28; Authors: Seach NL, Mattesich M, Abberton KM, Matsuda K, Rophael JA, Boyd RL, Morrison WA We have previously established a chamber model of tissue engineering which promotes de novo angiogenesis and vascularization of engrafted cells and tissue when combined with an extracellular matrix. Here we demonstrate the mouse chamber (MC) model can sustain ectopic grafts of murine fetal thymus lobes and, to a limited degree, human pediatric thymus tissue, resulting in de novo T cell production. Silicone chambers containing Matrigel(R) and thymus tissue were placed around exposed epigastric vessels and the ends sealed with bone wax, before implantation into the inguinal fat pad of athymic Balb/c<sup>nu/nu</sup> (nude) mice. Murine, embryonic day 15 (E15) thymus grafts were found to be well-vascularized and viable within the mouse chamber upon harvest at week 11. In contrast, engraftment of both adult murine and peadiatric human thymus tissue was limited, with only one out of seven human thymus grafts sustaining mature, murine-derived T cell development. Increased CD4+ and CD8+ T cell numbers were observed in the peripheral blood (PB) of nude mice within two weeks post E15 thymus- MC grafts (n=8), compared to nude control mice. PB T cell percentage and subset distribution were comparable to mice receiving conventional thymus kidney capsule (KC) grafts. T cell function of both KC- and MC- E15 thymus grafts was established via successful rejection of MHC-mismatched skin grafts. Sustained growth of fetal thymus tissue in the MC provides an alternative model for the study of thymopoiesis and related applications of T cell-mediated immunity. PMID: 19715386 [PubMed - as supplied by publisher] |
| Initial study on fibers and coatings for the fabrication of bioscaffolds.
September 1, 2009 at 6:11 am
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| | Initial study on fibers and coatings for the fabrication of bioscaffolds. P R Health Sci J. 2009 Sep;28(3):258-65 Authors: Pantojas VM, Velez E, Hernández D, Otaño W Scaffolds composed of a mixture of poly (L-lactic) acid (PLLA) and polyethylene glycol (PEG) biodegradable polymers were prepared by electrospinning. Three-dimensional scaffolds of highly porous non-woven fibers were produced for biomedical applications and coated with calcium phosphate for bone tissue engineering. A mixture (80/20) of PLLA/PEG was dissolved at 5.7%, 7%, 8% and 9% blend solution concentrations. The structure and morphology of the scaffolds were investigated by scanning electron microscopy. Average fiber diameters ranging from 600 nm to 800 nm were obtained as result of the change in viscosity. The low polymer concentration fibers were found to be flat with fused junctions between fibers. For high polymer concentrations fibers they were cylindrical with fibers overlaying each other. For samples deposited at 9% concentration, individual fibers contained pores on their surface with nanometric dimensions. In addition, thin films of calcium deficient hydroxyapatite were prepared by rf magnetron sputtering on silicon substrates heated to temperatures between 300-6000C. These results suggest that it is feasible to fabricate biopolymer scaffolds using methods combining electrospinning and sputtering techniques. PMID: 19715118 [PubMed - in process] |
| Downregulation of miRNA-200c links breast cancer stem cells with normal stem cells.
September 1, 2009 at 6:11 am
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| | Downregulation of miRNA-200c links breast cancer stem cells with normal stem cells. Cell. 2009 Aug 7;138(3):592-603 Authors: Shimono Y, Zabala M, Cho RW, Lobo N, Dalerba P, Qian D, Diehn M, Liu H, Panula SP, Chiao E, Dirbas FM, Somlo G, Pera RA, Lao K, Clarke MF Human breast tumors contain a breast cancer stem cell (BCSC) population with properties reminiscent of normal stem cells. We found 37 microRNAs that were differentially expressed between human BCSCs and nontumorigenic cancer cells. Three clusters, miR-200c-141, miR-200b-200a-429, and miR-183-96-182 were downregulated in human BCSCs, normal human and murine mammary stem/progenitor cells, and embryonal carcinoma cells. Expression of BMI1, a known regulator of stem cell self-renewal, was modulated by miR-200c. miR-200c inhibited the clonal expansion of breast cancer cells and suppressed the growth of embryonal carcinoma cells in vitro. Most importantly, miR-200c strongly suppressed the ability of normal mammary stem cells to form mammary ducts and tumor formation driven by human BCSCs in vivo. The coordinated downregulation of three microRNA clusters and the similar functional regulation of clonal expansion by miR-200c provide a molecular link that connects BCSCs with normal stem cells. PMID: 19665978 [PubMed - indexed for MEDLINE] |
| Locally-administered antibiotics in wounds in a limb.
September 1, 2009 at 6:11 am
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| | Locally-administered antibiotics in wounds in a limb. J Bone Joint Surg Br. 2009 Aug;91(8):1106-9 Authors: Branstetter JG, Jackson SR, Haggard WO, Richelsoph KC, Wenke JC We used a goat model of a contaminated musculoskeletal defect to determine the effectiveness of rapidly-resorbing calcium-sulphate pellets containing amikacin to reduce the local bacterial count. Our findings showed that this treatment eradicated the bacteria quickly, performed as well as standard polymethylmethacrylate mixed with an antibiotic and had many advantages over the latter. The pellets were prepared before surgery and absorbed completely. They released all of the antibiotic and did not require a subsequent operation for their removal. Our study indicated that locally administered antibiotics reduced bacteria within the wound rapidly. This method of treatment may have an important role in decreasing the rate of infection in contaminated wounds. PMID: 19651846 [PubMed - indexed for MEDLINE] |
| An overview of autologous chondrocyte implantation.
September 1, 2009 at 6:11 am
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| | An overview of autologous chondrocyte implantation. J Bone Joint Surg Br. 2009 Aug;91(8):997-1006 Authors: Gikas PD, Bayliss L, Bentley G, Briggs TW Chondral damage to the knee is common and, if left untreated, can proceed to degenerative osteoarthritis. In symptomatic patients established methods of management rely on the formation of fibrocartilage which has poor resistance to shear forces. The formation of hyaline or hyaline-like cartilage may be induced by implanting autologous, cultured chondrocytes into the chondral or osteochondral defect. Autologous chondrocyte implantation may be used for full-thickness chondral or osteochondral injuries which are painful and debilitating with the aim of replacing damaged cartilage with hyaline or hyaline-like cartilage, leading to improved function. The intermediate and long-term functional and clinical results are promising. We provide a review of autologous chondrocyte implantation and describe our experience with the technique at our institution with a mean follow-up of 32 months (1 to 9 years). The procedure is shown to offer statistically significant improvement with advantages over other methods of management of chondral defects. PMID: 19651824 [PubMed - indexed for MEDLINE] |
| Host cell detection of noncoding stuffer DNA contained in helper-dependent adenovirus vectors leads to epigenetic repression of transgene expression.
September 1, 2009 at 6:11 am
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| | Host cell detection of noncoding stuffer DNA contained in helper-dependent adenovirus vectors leads to epigenetic repression of transgene expression. J Virol. 2009 Sep;83(17):8409-17 Authors: Ross PJ, Kennedy MA, Parks RJ Helper-dependent adenovirus (hdAd) vectors have shown great promise as therapeutic gene delivery vehicles in gene therapy applications. However, the level and duration of gene expression from hdAd can differ considerably depending on the nature of the noncoding stuffer DNA contained within the vector. For example, an hdAd containing 22 kb of prokaryotic DNA (hdAd-prok) expresses its transgene 60-fold less efficiently than a similar vector containing eukaryotic DNA (hdAd-euk). Here we have determined the mechanistic basis of this phenomenon. Although neither vector was subjected to CpG methylation and both genomes associated with cellular histones to similar degrees, hdAd-prok chromatin was actively deacetylated. Insertion of an insulator element between the transgene and the bacterial DNA derepressed hdAd-prok, suggesting that foreign DNA nucleates repressive chromatin structures that spread to the transgene. We found that Sp100B/Sp100HMG and Daxx play a role in repressing transgene expression from hdAd and act independently of PML bodies. Thus, we have identified nuclear factors involved in recognizing foreign DNA and have determined the mechanism by which associated genes are repressed. PMID: 19515759 [PubMed - indexed for MEDLINE] |
| Multiple stimulations for muscle-nerve-blood vessel unit in compensatory hypertrophied skeletal muscle of rat surgical ablation model.
September 1, 2009 at 6:11 am
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| | Multiple stimulations for muscle-nerve-blood vessel unit in compensatory hypertrophied skeletal muscle of rat surgical ablation model. Histochem Cell Biol. 2009 Jul;132(1):59-70 Authors: Tamaki T, Uchiyama Y, Okada Y, Tono K, Nitta M, Hoshi A, Akatsuka A Tissue inflammation and multiple cellular responses in the compensatory enlarged plantaris (OP Plt) muscle induced by surgical ablation of synergistic muscles (soleus and gastrocnemius) were followed over 10 weeks after surgery. Contralateral surgery was performed in adult Wistar male rats. Cellular responses in muscle fibers, blood vessels and nerve fibers were analyzed by immunohistochemistry and electron microscopy. Severe muscle fiber damage and disappearance of capillaries associated with apparent tissue edema were observed in the peripheral portion of OP Plt muscles during the first week, whereas central portions were relatively preserved. Marked cell activation/proliferation was also mainly observed in peripheral portions. Similarly, activated myogenic cells were seen not only inside but also outside of muscle fibers. The former were likely satellite cells and the latter may be interstitial myogenic cells. One week after surgery, small muscle fibers, small arteries and capillaries and several branched-muscle fibers were evident in the periphery, thus indicating new muscle fiber and blood vessel formation. Proliferating cells were also detected in the nerve bundles in the Schwann cell position. These results indicate that the compensatory stimulated/enlarged muscle is a suitable model for analyzing multiple physiological cellular responses in muscle-nerve-blood vessel units under continuous stretch stimulation. PMID: 19322581 [PubMed - indexed for MEDLINE] |
| Anabolic-androgenic steroid does not enhance compensatory muscle hypertrophy but significantly diminish muscle damages in the rat surgical ablation model.
September 1, 2009 at 6:11 am
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| | Anabolic-androgenic steroid does not enhance compensatory muscle hypertrophy but significantly diminish muscle damages in the rat surgical ablation model. Histochem Cell Biol. 2009 Jul;132(1):71-81 Authors: Tamaki T, Uchiyama Y, Okada Y, Tono K, Nitta M, Hoshi A, Akatsuka A Cellular responses in the compensatory hypertrophied (plantaris) muscle induced by surgical ablation of synergistic muscles (soleus and gastrocnemius) were determined during 10-week anabolic androgenic steroid (AAS) treatment. Adult Wistar male rats were divided randomly into the Control and Steroid groups, and contralateral surgery was performed. Nandrolone decanoate was administered to the Steroid group. [3H]thymidine and [14C]leucine labeling were used to determine the serial changes in cellular mitotic activity and amino acid uptake. Myogenic cells and cellular responses in blood vessels and nerve fibers were analyzed by immunohistochemistry. Significantly lower cellular mitotic activity associated with lower volume of muscle fiber necrosis was observed in the Steroid group during the first week. However, amino acid uptake and final muscle wet weight gain did not differ between the groups. Marked activation/proliferation of muscular, vascular, and peripheral nerve-related cells was seen with the inflammatory responses in both groups. However, this activation was dependent on the volume of muscle fiber damage and was not preferentially accelerated by AAS loading. These results indicated that AAS loading significantly diminished muscle fiber damages, but they did not accelerate final muscle wet weight gain and activation of myogenic, vascular, and peripheral nerve related cells in the compensatory enlarged muscles. PMID: 19319558 [PubMed - indexed for MEDLINE] |
| Tubular nanofiber scaffolds for tissue engineered small-diameter vascular grafts.
September 1, 2009 at 6:11 am
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| | Tubular nanofiber scaffolds for tissue engineered small-diameter vascular grafts. J Biomed Mater Res A. 2009 Jul;90(1):205-16 Authors: He W, Ma Z, Teo WE, Dong YX, Robless PA, Lim TC, Ramakrishna S Quick establishment of a confluent and stable endothelial cells (ECs) layer in the lumen of vascular grafts is critical for long-term patency of small-diameter vascular grafts. The objective of the study was to fabricate tubular nanofiber scaffolds, incorporate ECs onto the lumen of the scaffolds, and establish an animal model to prove the basic concept of using the scaffolds as vascular grafts. Poly(L-lactic acid)-co-poly(epsilon-caprolactone) P(LLA-CL 70:30) tubular nanofiber scaffolds were fabricated by electrospinning onto a rotating mandrel. Collagen was coated onto the scaffolds after air plasma treatment. Structure and mechanical property of the scaffolds were studied by scanning electron microscopy and tensile stress measurement, respectively. Human coronary artery endothelial cells (HCAECs) were rotationally seeded onto the lumen of the scaffolds at the speed of 6 rpm for 4 h through a customized seeding device, followed with static culture. Results showed evenly distributed and well-spread HCAECs throughout the lumen of the scaffold from 1 day onward to 10 days after seeding. Further, HCAECs maintained phenotypic expression of PECAM-1. To prove the basic concept of using the scaffolds as vascular grafts, acellular tubular P(LLA-CL) nanofiber scaffolds (inner diameter 1 mm) were implanted into rabbits to replace the inferior superficial epigastric veins. Results showed the scaffolds sustained the surgical process, kept the structure integrity, and showed the patency for 7 weeks. PMID: 18491396 [PubMed - indexed for MEDLINE] | | | 
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