| NIH awards Einstein $3.5 million to study epigenomics of human health and disease
September 17, 2009 at 6:52 pm
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| Penn State College of Medicine research isolates liver cancer stem cells prior to tumor formation
September 17, 2009 at 5:52 pm
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| Fluidigm's Upcoming Stem Cell Culture Chip to Speed Development, Reduce Complexity and Lower Costs
September 17, 2009 at 3:52 pm
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| UGA geneticist receives $2 million federal stimulus grant for research on the thymus
September 17, 2009 at 3:52 pm
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| Rare genetic disease successfully reversed using stem cell transplantation
September 17, 2009 at 1:51 pm
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| Egg Donor Proposal Stirs Concern; CIRM Says Language is 'Placeholder'
September 17, 2009 at 1:50 pm
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| | The Center for Genetics and Society Thursday raised "serious concerns" about some of the matters to be discussed at today's meeting of the research standards group of the $3 billion California stem cell agency.CIRM, however, said the center has "misconstrued the intent of the proposed changes."In a letter to CIRM, the Oakland, Ca., organization center referred to preliminary language contained in |
| Correction
September 17, 2009 at 1:29 pm
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| | The "Prop. 71 Minutia" item on Sept. 16 contained a quote that referred to "advice" from the Little Hoover Commission that CIRM should lower its quorum requirements. A draft of the Hoover report contained that recommendation, but it was omitted in the final version. The final report said the super-quorum requirement was "restrictive" and "problematic" but said the problem would be eased by |
| Bioaesthetics and regenerative medicine
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 635-637.
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| Launching intravenous bone marrow cell trials for acute stroke
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 639-641.
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| News & Views in ... Regenerative Medicine
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 643-645.
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| Industry Update: Latest developments in stem cell research and regenerative medicine
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 647-657.
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| Interview: Discussions on the development of human embryonic stem cell-based therapies
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 659-661.
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| Research Highlights
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 663-666.
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| Hair follicle neogenesis induced by cultured human scalp dermal papilla cells
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 667-676.
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| Conjunctival epithelial cells maintain stem cell properties after long-term culture and cryopreservation
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 677-687.
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| Ficoll-Paque™ versus Lymphoprep™: a comparative study of two density gradient media for therapeutic bone marrow mononuclear cell preparations
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 689-696.
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| Pulp and dentin tissue engineering and regeneration: current progress
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 697-707.
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| Intracoronary blood- or bone marrow-derived cell transplantation in patients with ischemic heart disease
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 709-719.
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| Engineering microenvironments for embryonic stem cell differentiation to cardiomyocytes
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 721-732.
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| Microencapsulated stem cells for tissue repairing: implications in cell-based myocardial therapy
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 733-745.
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| Reclaiming a natural beauty: whole-organ engineering with natural extracellular materials
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 747-758.
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| Induced pluripotent stem cells in regenerative medicine: an argument for continued research on human embryonic stem cells
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 759-769.
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| Acknowledgements
September 17, 2009 at 11:42 am
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| Regenerative Medicine , September 2009, Vol. 4, No. 5, Pages 781-781.
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| ImmunoCellular Therapeutics' Immunology Platform Featured in Report on the Future of Cancer Research
September 17, 2009 at 10:51 am
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| Spray-spinning: a novel method for making alginate/chitosan fibrous scaffold.
September 17, 2009 at 6:46 am
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| | Spray-spinning: a novel method for making alginate/chitosan fibrous scaffold. J Mater Sci Mater Med. 2009 Sep 16; Authors: Wang JZ, Huang XB, Xiao J, Li N, Yu WT, Wang W, Xie WY, Ma XJ, Teng YL The subject of our investigations was the process of obtaining alginate/chitosan polyelectrolyte complex (PEC) fibers. In this study, a novel method named "spray-spinning" was developed for the making of these hybrid fibers. In spray-spinning, a chitosan solution was sprayed into a flowing sodium alginate solution and sheared into streamlines. The elongated streamlines subsequently transformed into alginate/chitosan PEC fibers. Average diameter of the fibers increased with the increasing of chitosan concentration used in spinning. The fibers showed a high water-absorbability of about 45 folds of water to their dry weight and retained their integrity after incubation in Minimum Essential Medium (MEM) for up to 30 days. In vitro co-culture experiments indicated that the fibers could support the three-dimensional growth of HepG2 cells and did not display any cyto-toxicity. Moreover, in vivo implanting experiments indicated that the connective tissue cells infiltrated into the implanted fibrous scaffolds in 3 weeks after surgery. These results demonstrated the potential applications of the as-spun fibers in regenerative medicine and tissue engineering. PMID: 19756966 [PubMed - as supplied by publisher] |
| Variable optimization for the formation of three-dimensional self-organized heart muscle.
September 17, 2009 at 6:46 am
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| | Variable optimization for the formation of three-dimensional self-organized heart muscle. In Vitro Cell Dev Biol Anim. 2009 Sep 15; Authors: Khait L, Hodonsky CJ, Birla RK Cardiac tissue-engineering research is focused on the development of functional three-dimensional (3D) heart muscle in vitro. These models allow the detailed study of critical events in organogenesis, such as the establishment of cell-cell communication and construction and modification of the extracellular matrix. We have previously described a model for 3D heart muscle, termed cardioids, formed by the spontaneous delamination of a cohesive monolayer of primary cells in the absence of any synthetic scaffolding material. In an earlier publication, we have shown that, upon electrical stimulation, cardioids generate a twitch force in the range of 200-300 microN, generate a specific force (twitch force normalized to total cross-sectional area) of 2-4 kN/m(2), and can be electrically paced at frequencies of up to 10 Hz without any notable fatigue. We have two objectives for the current study: model development and model optimization. Our model development efforts are focused on providing additional characterization of the cardioid model. In this study, we show for the first time that cardioids show a pattern of gene expression comparable to that of cells cultured in two dimensions on tissue culture plastic and normal mammalian heart muscle. Compared with primary cardiac cells cultured on tissue culture plastic, the expression of alpha-myosin heavy chain (MHC), beta-MHC, SERCA2, and phospholamban was significantly higher in cardioids. Our second objective, model optimization, is focused on evaluating the effect of several cell culture variables on cardioid formation and function. Specifically, we looked at the effect of plating density (1.0-4.0 x 10(6) cells per cardioid), concentration of two adhesion proteins (laminin at 0.2-2.0 microg/cm(2) and fibronectin at 1-10 microg/cm(2)), myocyte purity (using preplating times of 15 and 60 min), and ascorbic acid stimulation (1-100 microl/ml). For our optimization studies, we utilized twitch force in response to electrical stimulation as our endpoint metric. Based on these studies, we found that cardioids formed with a plating density in the range 3-4 x 10(6) cells per cardioid generated the maximum twitch force, whereas increasing the surface adhesion protein (using either laminin or fibronectin) and increasing the myocyte purity both resulted in a decrease in twitch force. In addition, increasing the ascorbic acid concentration resulted in an increase in the baseline force of cardioids, which was recorded in the absence of electrical stimulation. Based on the model development studies, we have shown that cardioids do indeed exhibit a gene expression pattern similar to normal mammalian heart muscle. This provides further validity for the cardioid model. Based on the model optimization studies, we have identified specific cell culture regimes which support cardioid formation and function. These results are specific to the cardioid model; however, they may be translated and applied to other tissue-engineering models. Collectively, the work described in this study provides insight into the formation of functional 3D heart muscle and the effect of several cell culture variables on tissue formation and function. PMID: 19756885 [PubMed - as supplied by publisher] |
| [Tissue engineering of bone tissue : Principles and clinical applications.]
September 17, 2009 at 6:46 am
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| | [Tissue engineering of bone tissue : Principles and clinical applications.] Unfallchirurg. 2009 Sep;112(9):785-95 Authors: Schmidt-Rohlfing B, Tzioupis C, Menzel CL, Pape HC Complex fractures are still a major clinical challenge. The treatment options of large bony defects either with autografts or allografts are limited in terms of material availability and tissue in-growth. Tissue engineering might offer a solution to this problem. In an interdisciplinary approach artificial bony tissue can be generated which mimics normal bone in terms of function and morphology. So far tissue engineering of bone is mainly confined to laboratory investigations whereas clinical applications are still in the beginning. This manuscript presents the most important scaffolds as well as growth factors and cell systems. Furthermore, it focuses on clinical studies for the treatment of large bony defects using tissue engineered cell-matrix constructs. PMID: 19756458 [PubMed - in process] |
| Cryo-Imaging of Fluorescently-Labeled Single Cells in a Mouse.
September 17, 2009 at 6:46 am
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| | Cryo-Imaging of Fluorescently-Labeled Single Cells in a Mouse. Proc Soc Photo Opt Instrum Eng. 2009 Jan 1;7262:72620W-72620W8 Authors: Steyer GJ, Roy D, Salvado O, Stone ME, Wilson DL We developed a cryo-imaging system to provide single-cell detection of fluorescently labeled cells in mouse, with particular applicability to stem cells and metastatic cancer. The Case cryo-imaging system consists of a fluorescence microscope, robotic imaging positioner, customized cryostat, PC-based control system, and visualization/analysis software. The system alternates between sectioning (10-40 mum) and imaging, collecting color brightfield and fluorescent block-face image volumes >60GB. In mouse experiments, we imaged quantum-dot labeled stem cells, GFP-labeled cancer and stem cells, and cell-size fluorescent microspheres. To remove subsurface fluorescence, we used a simplified model of light-tissue interaction whereby the next image was scaled, blurred, and subtracted from the current image. We estimated scaling and blurring parameters by minimizing entropy of subtracted images. Tissue specific attenuation parameters were found [u(T) : heart (267 +/- 47.6 mum), liver (218 +/- 27.1 mum), brain (161 +/- 27.4 mum)] to be within the range of estimates in the literature. "Next image" processing removed subsurface fluorescence equally well across multiple tissues (brain, kidney, liver, adipose tissue, etc.), and analysis of 200 microsphere images in the brain gave 97+/-2% reduction of subsurface fluorescence. Fluorescent signals were determined to arise from single cells based upon geometric and integrated intensity measurements. Next image processing greatly improved axial resolution, enabled high quality 3D volume renderings, and improved enumeration of single cells with connected component analysis by up to 24%. Analysis of image volumes identified metastatic cancer sites, found homing of stem cells to injury sites, and showed microsphere distribution correlated with blood flow patterns.We developed and evaluated cryo-imaging to provide single-cell detection of fluorescently labeled cells in mouse. Our cryo-imaging system provides extreme (>60GB), micron-scale, fluorescence, and bright field image data. Here we describe our image pre-processing, analysis, and visualization techniques. Processing improves axial resolution, reduces subsurface fluorescence by 97%, and enables single cell detection and counting. High quality 3D volume renderings enable us to evaluate cell distribution patterns. Applications include the myriad of biomedical experiments using fluorescent reporter gene and exogenous fluorophore labeling of cells in applications such as stem cell regenerative medicine, cancer, tissue engineering, etc. PMID: 19756213 [PubMed - as supplied by publisher] |
| "Opening" the mesenchymal stem cell tool box.
September 17, 2009 at 6:46 am
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| | "Opening" the mesenchymal stem cell tool box. Eur J Dent. 2009 Jul;3(3):240-9 Authors: Zeidán-Chuliá F, Noda M Adult mesenchymal stem cells (MSCs) are adherent stromal cells able to self-renew and differentiate into a wide variety of cells and tissues. MSCs can be obtained from distinct tissue sources and have turned out to be successfully manipulated in vitro. As adult stem cells, MSCs are less tumorigenic than their embryonic correlatives and posses another unique characteristic which is their almost null immunogenicity. Moreover, these cells seem to be immunosuppressive in vitro. These facts together with others became MSCs a promising subject of study for future approaches in bioengineering and cell-based therapy. On the other hand, new strategies to achieve long-term integration as well as efficient differentiation of these cells at the area of the lesion are still challenging, and the signalling pathways ruling these processes are not completely well characterized. In this review, we are going summarize the general landscape and current status of the MSC tool as well as their wide potential in tissue engineering, from neuronal to tooth replacement. Highlights and pitfalls for further clinical applications will be discussed. PMID: 19756201 [PubMed - in process] |
| 2007 AIChE Alpha Chi Sigma Award: From Material to Tissue: Biomaterial Development, Scaffold Fabrication, and Tissue Engineering.
September 17, 2009 at 6:46 am
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| | 2007 AIChE Alpha Chi Sigma Award: From Material to Tissue: Biomaterial Development, Scaffold Fabrication, and Tissue Engineering. AIChE J. 2008 Oct 29;54(12):3048-3067 Authors: Kretlow JD, Mikos AG The need for techniques to facilitate the regeneration of failing or destroyed tissues remains great with the aging of the worldwide population and the continued incidence of trauma and diseases such as cancer. A 16-year history in biomaterial scaffold development and tissue engineering is examined, beginning with the synthesis of novel materials and fabrication of 3D porous scaffolds. Exploring cell-scaffold interactions and subsequently cellular delivery using biomaterial carriers, we have developed a variety of techniques for bone and cartilage engineering. In addition to delivering cells, we have utilized growth factors, DNA, and peptides to improve the in vitro and in vivo regeneration of tissues. This review covers important developments and discoveries within our laboratory, and the increasing breadth in the scope of our work within the expanding field of tissue engineering is presented. PMID: 19756176 [PubMed - as supplied by publisher] |
| Neural Network Analysis Identifies Scaffold Properties Necessary for In Vitro Chondrogenesis in Elastin-like Polypeptide Biopolymer Scaffolds.
September 17, 2009 at 6:46 am
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| | Neural Network Analysis Identifies Scaffold Properties Necessary for In Vitro Chondrogenesis in Elastin-like Polypeptide Biopolymer Scaffolds. Tissue Eng Part A. 2009 Sep 15; Authors: Nettles DL, Haider MA, Chilkoti A, Setton LA The successful design of biomaterial scaffolds for articular cartilage tissue engineering requires an understanding of the impact of combinations of material formulation parameters on diverse and competing functional outcomes of biomaterial performance. This study sought to explore the use of a type of unsupervised artificial network, a self-organizing map, to identify relationships between scaffold formulation parameters (crosslink density, molecular weight, and concentration) and 11 such outcomes (including mechanical properties, matrix accumulation, metabolite usage and production, and histological appearance) for scaffolds formed from crosslinked elastin-like polypeptide (ELP) hydrogels. The artificial neural network recognized patterns in functional outcomes and provided a set of relationships between ELP formulation parameters and measured outcomes. Mapping resulted in the best mean separation amongst neurons for mechanical properties and pointed to crosslink density as the strongest predictor of most outcomes, followed by ELP concentration. The map also grouped formulations together that simultaneously resulted in the highest values for matrix production, greatest changes in metabolite consumption or production, and highest histological scores, indicating that the network was able to recognize patterns amongst diverse measurement outcomes. These results demonstrated the utility of artificial neural network tools for recognizing relationships in systems with competing parameters, toward the goal of optimizing and accelerating the design of biomaterial scaffolds for articular cartilage tissue engineering. PMID: 19754250 [PubMed - as supplied by publisher] |
| VEGF inhibits BMP2 expression in Rat Mesenchymal Stem Cells.
September 17, 2009 at 6:46 am
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| | VEGF inhibits BMP2 expression in Rat Mesenchymal Stem Cells. Tissue Eng Part A. 2009 Sep 15; Authors: Schönmeyr BH, Soares M, Avraham T, Clavin NW, Gewalli F, Mehrara BJ Introduction: While several studies report that BMPs and VEGF can act synergistically to improve bone tissue engineering, others suggest that VEGF inhibits osteogenesis. The purpose of these experiments was therefore to evaluate the effect of dual transfection of these growth factors and potential mechanisms of interaction on gene expression and osteogenesis in vitro and in vivo. Methods: Marrow-derived mesenchymal stem cells (MSCs) were exposed to recombinant VEGF protein or transfected with adenoviruses encoding BMP2, VEGF, or LacZ in a variety of ratios. Alterations in gene and protein expression in vitro as well as bone formation in vivo were assessed. Results: MSC exposure to AdV-VEGF or recombinant VEGF inhibited BMP2 mRNA expression, protein production and MSC differentiation. Co-culture experiments revealed that BMP2 suppression occurs through both an autocrine and paracrine mechanism, occurring at the transcriptional level. Compared to controls, co-transfection of VEGF and BMP2 transgenes prevented ectopic bone formation in vivo. Conclusion: VEGF is a potent inhibitor of BMP2 expression in MSCs and supplementation or overexpression of VEGF inhibits osteogenesis in vitro and ectopic bone formation in vivo. Strategies to utilize MSCs in bone tissue engineering therefore require careful optimization and precise delivery of growth factors for maximal bone formation. PMID: 19754224 [PubMed - as supplied by publisher] |
| Characteristic change and loss of in vivo osteogenic abilities of human bone marrow stromal cells during passage.
September 17, 2009 at 6:46 am
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| | Characteristic change and loss of in vivo osteogenic abilities of human bone marrow stromal cells during passage. Tissue Eng Part A. 2009 Sep 15; Authors: Agata H, Asahina I, Watanabe N, Ishii Y, Kubo N, Ohshima S, Yamazaki M, Tojo A, Kagami H Although human bone marrow stromal cells (BMSCs) have the ability to form bone when transplanted, the responsible factors for in vivo osteogenic abilities are poorly understood. Here, we report conditions that are required for human BMSCs to demonstrate their in vivo osteogenic abilities. BMSCs were obtained from healthy donors and their in vivo osteogenic abilities were analyzed. Transplantation analyses revealed that passage number and length of osteogenic induction significantly affected ectopic bone formation. Although two weeks induction increased the percentage of success in bone formation compared to one week induction, BMSCs completely lost their in vivo osteogenic ability after passage 4 regardless of the length of osteogenic induction. Despite their in vivo osteogenic ability, no significant difference was observed in alkaline phosphatase activity or gene expression of osteogenic markers between BMSCs at passages 1 and 3. Differences were only observed in in vitro mineralizing abilities. Application of bFGF helped to maintain the BMSCs in vivo osteogenic ability, while bFGF altered cell growth and expression of HLA-DR. The results strongly suggest that there are several required conditions for human BMSCs to demonstrate their bone-forming capabilities, which should be further investigated and considered when designing a protocol for clinical bone tissue engineering. PMID: 19754223 [PubMed - as supplied by publisher] |
| PROTEOGLYCAN AND COLLAGEN ACCUMULATION BY PASSAGED CHONDROCYTES CAN BE ENHANCED THROUGH SIDE BY SIDE CULTURE WITH PRIMARY CHONDROCYTES.
September 17, 2009 at 6:46 am
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| | PROTEOGLYCAN AND COLLAGEN ACCUMULATION BY PASSAGED CHONDROCYTES CAN BE ENHANCED THROUGH SIDE BY SIDE CULTURE WITH PRIMARY CHONDROCYTES. Tissue Eng Part A. 2009 Sep 15; Authors: Taylor DW, Ahmed N, Gan L, Gross AE, Kandel R Identifying a source of sufficient numbers of chondrocytes for cartilage tissue engineering is a major factor limiting its use clinically. Previously we demonstrated that combined co-culture of passaged dedifferentiated articular chondrocytes with primary bovine chondrocytes will induce their redifferentiation. In this study we determine if these two cell types have to be in contact, whether human chondrocytes respond similarly, and if the ability of primary cells to influence passaged cells depends on the age of the donor. Co-culture of primary and passaged bovine chondrocytes grown on filter inserts placed in the same culture well but not in direct contact resulted in the passaged cells accumulating matrix rich in proteoglycans and type II collagen. There was upregulation of type II collagen and Sox9 and decrease in type I collagen gene expression in the passaged cells, to levels not significantly different than in primary chondrocytes. Passaged chondrocytes obtained from older animals responded similarly to cells from younger animals. As well, passaged human chondrocytes were also induced to form cartilage tissue when placed in side-by-side culture with bovine chondrocytes, this data suggests that a soluble factor(s) may be responsible for redifferentiation of passaged chondrocytes and that it is not species specific. The responsiveness of human chondrocytes to this factor(s) suggests that this approach may be suitable to overcome the problem of limited chondrocyte numbers for cartilage tissue engineering. PMID: 19754222 [PubMed - as supplied by publisher] |
| Synthesis and Characterization of Degradable Polar Hydrophobic Ionic Polyurethane Scaffolds for Vascular Tissue Engineering Applications.
September 17, 2009 at 6:46 am
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| | Synthesis and Characterization of Degradable Polar Hydrophobic Ionic Polyurethane Scaffolds for Vascular Tissue Engineering Applications. Biomacromolecules. 2009 Sep 15; Authors: Sharifpoor S, Labow RS, Santerre JP In tissue engineering, the ability to manipulate scaffold design characteristics is important to achieve functional tissue regeneration. In this study, degradable polar hydrophobic ionic polyurethane (D-PHI) porous scaffolds were synthesized using a lysine-based divinyl oligomer (DVO). Optimization studies on the DVO and D-PHI scaffold synthesis were conducted to maximize isocyanate and methacrylate monomer conversion, respectively. D-PHI scaffold properties were manipulated through the introduction of a lysine-based cross-linker. Specifically, increasing D-PHI cross-linker concentration resulted in an increase of the elastic modulus (0.5-21 MPa), a decrease of the elongation-at-yield (45-5%) and a reduction of scaffold swelling (170-100%). Based on a preliminary study with A10 vascular smooth muscle cells, D-PHI scaffolds demonstrated the ability to support cell adhesion and growth during 2 weeks of culture, suggesting their potential suitability for longer term vascular tissue engineering. The versatility of the D-PHI properties may allow for the tailoring of cell-material interaction and ultimately functional tissue regeneration. PMID: 19754121 [PubMed - as supplied by publisher] |
| Generation and transplantation of an autologous vascularized bioartificial human tissue.
September 17, 2009 at 6:46 am
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| | Generation and transplantation of an autologous vascularized bioartificial human tissue. Transplantation. 2009 Jul 27;88(2):203-10 Authors: Mertsching H, Schanz J, Steger V, Schandar M, Schenk M, Hansmann J, Dally I, Friedel G, Walles T BACKGROUND: The lack of transplant vascularization forecloses the generation and clinical implementation of bioartificial tissues. We developed techniques to generate a bioartificial human tissue with an innate vascularization. The tissue was implanted clinically as proof of concept to evaluate vascular network thrombogenicity and tissue viability after transplantation. METHODS: A porcine small bowl segment was decellularized in a two-step procedure, preserving its vascular structures. The extracellular matrix was characterized quantitatively for DNA residues and protein composition. The vascular remainings were reseeded with human endothelial cells in a dynamic tissue culture. The engineered tissue was characterized by (1) histology, (2) immune-histology, (3) life-dead assay, and (4) metabolic activity. To evaluate the tissue capabilities, it was implanted clinically and recovered after 1 week. RESULTS: Tissue preparation with sodium desoxycholate monohydrate solution resulted in an incomplete decellularization. Cell residues were removed by additional tissue incubation with DNAse. The human endothelial cells formed a viable endothelium inside the primarily porcine extracellular matrix, expressing CD31, Flk-1, and vascular endothelium-cadherin. The metabolic activity of the bioartificial tissue increased continuously over time in vitro. Clinical tissue transplantation confirmed vessel patency and tissue viability for 1 week. CONCLUSIONS: The feasibility to bioengineer a human tissue with an innate vascularization has been shown in vitro and the clinical setting. These results may open the door for the clinical application of various sophisticated bioartificial tissue substitutes and organ replacements. PMID: 19623015 [PubMed - indexed for MEDLINE] |
| Origins.
September 17, 2009 at 6:46 am
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| | Origins. Tissue Eng Part A. 2009 Jul;15(7):1449-50 Authors: Lysaght MJ, Crager J PMID: 19327019 [PubMed - indexed for MEDLINE] |
| Long-term survival and integration of transplanted engineered nervous tissue constructs promotes peripheral nerve regeneration.
September 17, 2009 at 6:46 am
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| | Long-term survival and integration of transplanted engineered nervous tissue constructs promotes peripheral nerve regeneration. Tissue Eng Part A. 2009 Jul;15(7):1677-85 Authors: Huang JH, Cullen DK, Browne KD, Groff R, Zhang J, Pfister BJ, Zager EL, Smith DH Although peripheral nerve injury is a common consequence of trauma or surgery, there are insufficient means for repair. In particular, there is a critical need for improved methods to facilitate regeneration of axons across major nerve lesions. Here, we engineered transplantable living nervous tissue constructs to provide a labeled pathway to guide host axonal regeneration. These constructs consisted of stretch-grown, longitudinally aligned living axonal tracts inserted into poly(glycolic acid) tubes. The constructs (allogenic) were transplanted to bridge an excised segment of sciatic nerve in the rat, and histological analyses were performed at 6 and 16 weeks posttransplantation to determine graft survival, integration, and host regeneration. At both time points, the transplanted constructs were found to have maintained their pretransplant geometry, with surviving clusters of graft neuronal somata at the extremities of the constructs spanned by tracts of axons. Throughout the transplanted region, there was an intertwining plexus of host and graft axons, suggesting that the transplanted axons mediated host axonal regeneration across the lesion. By 16 weeks posttransplant, extensive myelination of axons was observed throughout the transplant region. Further, graft neurons had extended axons beyond the margins of the transplanted region, penetrating into the host nerve. Notably, this survival and integration of the allogenic constructs occurred in the absence of immunosuppression therapy. These findings demonstrate the promise of living tissue-engineered axonal constructs to bridge major nerve lesions and promote host regeneration, potentially by providing axon-mediated axonal outgrowth and guidance. PMID: 19231968 [PubMed - indexed for MEDLINE] |
| Practical induction system for dopamine-producing cells from bone marrow stromal cells using spermine-pullulan-mediated reverse transfection method.
September 17, 2009 at 6:46 am
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| | Practical induction system for dopamine-producing cells from bone marrow stromal cells using spermine-pullulan-mediated reverse transfection method. Tissue Eng Part A. 2009 Jul;15(7):1655-65 Authors: Nagane K, Kitada M, Wakao S, Dezawa M, Tabata Y Introduction of various kinds of exogenous genes is an important step for control of differentiation in stem cell biology and regenerative medicine. However, some kinds of cells are vulnerable to manipulations such as gene delivery. In this context, a gene introduction method with higher efficiency and safety is required. Bone marrow stromal cells (BMSCs) offer possibilities for clinical application because of their potential for expandability and ability to be auto-transplanted. In this study, we established an efficient induction system of dopamine-producing neuronal cells from BMSCs in several species using the spermine-pullulan-mediated reverse transfection technique. In this system, introduced exogenous plasmid genes were successfully transcribed and expressed as proteins in the cytoplasm of BMSCs with the smallest number of cell death. Microtubule-associated protein 2 and anti-beta-tubulin class III+ neurons were successfully delivered from human, monkey, and mouse BMSCs, and further treatment with trophic factors promoted differentiation of induced neuronal cells into dopamine-producing cells that were positive for tyrosine hydroxylase and secreted dopamine after high K+ stimulation in high-performance liquid chromatography analysis. Our study indicates the availability of the reverse transfection method for the induction of dopamine-producing neuronal cells from BMSCs, which is expected to apply to cell-based therapy in Parkinson's disease. PMID: 19196136 [PubMed - indexed for MEDLINE] |
| Synthesis of a tissue-engineered periosteum with acellular dermal matrix and cultured mesenchymal stem cells.
September 17, 2009 at 6:46 am
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| | Synthesis of a tissue-engineered periosteum with acellular dermal matrix and cultured mesenchymal stem cells. Tissue Eng Part A. 2009 Jul;15(7):1833-41 Authors: Schönmeyr B, Clavin N, Avraham T, Longo V, Mehrara BJ Periosteal grafts can aid in bone repair by providing bone progenitor cells and acting as a barrier to scar tissue. Unfortunately, these grafts have many of the same disadvantages as bone grafts (donor site morbidity and limited donor sites). In this article, we describe a method of synthesizing a periosteum-like material using acellular human dermis and osteoblasts or mesenchymal stem cells (MSC). We show that osteoblasts readily attach to and proliferate on the acellular human dermis in vitro. In addition, osteoblasts retained the potential for differentiation in response to bone morphogenetic protein stimulation. Cells grown on the acellular human dermis were efficiently transfected with adenoviruses with no evidence of cellular toxicity. To assess for in vivo cell delivery and bone-forming potential, the acellular human dermis was seeded with green fluorescent protein (GFP)-positive MSCs, transfected with bone morphogenetic protein 2, wrapped around the adductor muscle in syngeneic mice, and used to treat critical-sized mandibular defects in nude rats. After 3 weeks, GFP-positive cells were still present, and bone had replaced the interface between the muscle and the constructs. After 6 weeks, critical-sized bone defects had been successfully healed. In conclusion, we show that an acellular human dermis can be used to synthesize a tissue-engineered periosteum capable of delivering cells and osteoinductive proteins. PMID: 19125645 [PubMed - indexed for MEDLINE] |
| Enhanced tissue integration during cartilage repair in vitro can be achieved by inhibiting chondrocyte death at the wound edge.
September 17, 2009 at 6:46 am
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| | Enhanced tissue integration during cartilage repair in vitro can be achieved by inhibiting chondrocyte death at the wound edge. Tissue Eng Part A. 2009 Jul;15(7):1739-49 Authors: Gilbert SJ, Singhrao SK, Khan IM, Gonzalez LG, Thomson BM, Burdon D, Duance VC, Archer CW OBJECTIVE: Experimental wounding of articular cartilage results in cell death at the lesion edge. The objective of this study was to investigate whether inhibition of this cell death results in enhanced integrative cartilage repair. METHODS: Bovine articular cartilage discs (6 mm) were incubated in media containing inhibitors of necrosis (Necrostatin-1, Nec-1) or apoptosis (Z-VAD-FMK, ZVF) before cutting a 3 mm inner core. This core was left in situ to create disc/ring composites, cultured for up to 6 weeks with the inhibitors, and analyzed for cell death, sulfated glycosaminoglycan release, and tissue integration. RESULTS: Creating the disc/ring composites resulted in a significant increase in necrosis. ZVF significantly reduced necrosis and apoptosis at the wound edge. Nec-1 reduced necrosis. Both inhibitors reduced the level of wound-induced sulfated glycosaminoglycan loss. Toluidine blue staining and electron microscopy of cartilage revealed significant integration of the wound edges in disc/ring composites treated with ZVF. Nec-1 improved integration, but to a lesser extent. Push-out testing revealed that ZVF increased adhesive strength compared to control composites. CONCLUSIONS: This study shows that treatment of articular cartilage with cell death inhibitors during wound repair increases the number of viable cells at the wound edge, prevents matrix loss, and results in a significant improvement in cartilage-cartilage integration. PMID: 19119922 [PubMed - indexed for MEDLINE] |
| Tissue reactions to engineered cartilage based on poly-L-lactic acid scaffolds.
September 17, 2009 at 6:46 am
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| | Tissue reactions to engineered cartilage based on poly-L-lactic acid scaffolds. Tissue Eng Part A. 2009 Jul;15(7):1565-77 Authors: Fujihara Y, Asawa Y, Takato T, Hoshi K Tissue reactions against poly-L-lactic acid (PLLA) in engineered cartilage may influence the size or maturity of regenerative tissue. To understand the biological events in these reactions, we subcutaneously transplanted engineered constructs of PLLA scaffolds with or without human chondrocytes or atelocollagen in nude mice and evaluated neovascularization and macrophage activation, which can be assessed even in nude mice. Although not showing cartilage regeneration, PLLA alone demonstrated dense localization of macrophages and blood vessels, as well as a high level of interleukin-1 beta and tissue hemoglobin at 2 and 8 weeks. Otherwise, constructs with PLLA and chondrocytes with or without atelocollagen (PLLA/cell/gel or PLLA/cell) formed mature cartilage by 8 weeks, which was more prominent in PLLA/cell/gel. Although accumulation of macrophages and blood vessels in PLLA/cell/gel and PLLA/cell was comparable with that in PLLA at 2 weeks, that in PLLA/cell/gel markedly decreased by 8 weeks, with blood vessels and macrophages excluded into non-cartilage areas. Macrophage migration inhibitory factor could be involved in these suppressed tissue reactions, because it was expressed in chondrocytes of engineered cartilage. Intense tissue reactions inevitably occurred in biopolymers alone, but it is possible that maturation of engineered cartilage suppressed these reactions, which may contribute to circumventing deformity or malformation of engineered tissues. PMID: 19115823 [PubMed - indexed for MEDLINE] |
| Reconstruction of engineered uterine tissues containing smooth muscle layer in collagen/matrigel scaffold in vitro.
September 17, 2009 at 6:46 am
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| | Reconstruction of engineered uterine tissues containing smooth muscle layer in collagen/matrigel scaffold in vitro. Tissue Eng Part A. 2009 Jul;15(7):1611-8 Authors: Lü SH, Wang HB, Liu H, Wang HP, Lin QX, Li DX, Song YX, Duan CM, Feng LX, Wang CY OBJECTIVE: This study attempted to reconstruct engineered uterine tissues (EUTs) containing smooth muscle layer, akin to the normal uterine wall. METHODS: EUTs were reconstructed by seeding epithelial cells on top of the constructed stromal layer over smooth muscle layer. A self-made mold was used to keep the EUTs from contraction. At the same time, it provided static stretch to the EUTs. After 14 days of culture, the structure of the EUTs was analyzed histologically and immunohistochemically, or by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The expression of integrin beta3 subunit, heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), and HOXA-10 was detected by reverse transcription-polymerase chain reaction (RT-PCR). The ability of the EUTs supporting the development of embryos was estimated by coculturing embryos on the EUTs. We also tried a new method to reconstruct EUTs by mixing epithelial cell and stromal cells (1:2) in collagen/Matrigel to form an endometrial layer and putting it on top of the smooth muscle layer. The self-assembling ability of the endometrial epithelial cells and stromal cells in the reconstructed EUTs was analyzed histologically and immunohistochemically. RESULTS: The results found that the constructed EUTs with the first and the second method showed three-layered structures. The epithelial layer, stromal layer, and smooth muscle layer were stained by cytokeratin 18, vimentin, and alpha-actin, respectively. TEM showed that the cells in the EUTs reconstructed by the first method were attached to each other by apical tight junctions and rivet-like desmosomes. SEM showed protruded pinopodes, microvilli, and cilium of epithelial cells. The RT-PCR analysis showed that integrin beta3 subunit, HB-EGF, and HOXA-10 were expressed in EUTs. The coculture system of EUTs improved the development rate and quality of murine embryo significantly in comparison with those of control Chatot Ziomek Bavister culture. In the EUTs reconstructed by the second method, the epithelial cells demonstrated self-assembling ability and formed epithelial cell layer on top of the stromal layer and glandular tube-like structures in the stromal layer. Columnar epithelial cells existed in some parts of the epithelial layer. CONCLUSION: We engineered EUTs containing smooth muscle layer by two methods. The reconstructed EUTs could support the development of embryos. The epithelial cells showed self-assembling ability in the EUTs. PMID: 19061433 [PubMed - indexed for MEDLINE] |
| Assessment of polymer/bioactive glass-composite microporous spheres for tissue regeneration applications.
September 17, 2009 at 6:46 am
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| | Assessment of polymer/bioactive glass-composite microporous spheres for tissue regeneration applications. Tissue Eng Part A. 2009 Jul;15(7):1451-61 Authors: Keshaw H, Georgiou G, Blaker JJ, Forbes A, Knowles JC, Day RM Conformable scaffold materials capable of rapid vascularization and tissue infiltration would be of value in the therapy of inaccessible wounds. Microporous spheres of poly(D,L-lactide-co-glycolide) (PLGA) containing bioactive glass (BG) were prepared using a thermally induced phase separation (TIPS) technique, and the bioactivity, in vitro degradation, and tissue integration of the microporous spheres were assessed. Microporous spheres containing 10% (w/w) BG stimulated a significant increase in vascular endothelial growth factor secretion from myofibroblasts consistently over a 10-day period (p < 0.01) compared with the neat PLGA microporous spheres. The microporous spheres degraded steadily in vitro over a 16-week period, with the neat PLGA microporous spheres retaining 82% of their original weight and microporous spheres containing 10% (w/w) BG retaining 77%. Both types of microporous spheres followed a similar pattern of size reduction throughout the degradation study, resulting in a 23% and 20% reduction after 16 weeks for the neat PLGA microporous spheres and PLGA microporous spheres containing 10% (w/w) BG, respectively (p < 0.01). After in vivo implantation into a subcutaneous wound model, the TIPS microporous spheres became rapidly integrated (interspherically and intraspherically) with host tissue, including vascularization of voids inside the microporous sphere. The unique properties of TIPS microporous spheres make them ideally suited for regenerative medicine applications where tissue augmentation is required. PMID: 19061428 [PubMed - indexed for MEDLINE] | 
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