| Microfabricated arrays for high-throughput screening of cellular response to cyclic substrate deformation.
January 13, 2010 at 4:47 PM
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| | Microfabricated arrays for high-throughput screening of cellular response to cyclic substrate deformation. Lab Chip. 2010 Jan 21;10(2):227-34 Authors: Moraes C, Chen JH, Sun Y, Simmons CA Mechanical forces play an important role in regulating cellular function and have been shown to modulate cellular response to other factors in the cellular microenvironment. Presently, no technique exists to rapidly screen for the effects of a range of uniform mechanical forces on cellular function. In this work, we developed and characterized a novel microfabricated array capable of simultaneously applying cyclic equibiaxial substrate strains ranging in magnitude from 2 to 15% to small populations of adherent cells. The array is versatile, and capable of simultaneously generating a range of substrate strain fields and magnitudes. The design can be extended to combinatorially manipulate other mechanobiological culture parameters in the cellular microenvironment. As a first demonstration of this technology, the array was used to determine the effects of equibiaxial mechanical strain on activation of the canonical Wnt/beta-catenin signaling pathway in cardiac valve ! mesenchymal progenitor cells. This high-throughput approach to mechanobiological screening enabled the identification of a novel co-dependence between strain magnitude and duration of stimulation in controlling beta-catenin nuclear accumulation. More generally, this versatile platform has broad applicability in the fields of mechanobiology, tissue engineering and pathobiology. PMID: 20066251 [PubMed - in process] | | |
| Preparation of the acellular scaffold of the spinal cord and the study of biocompatibility.
January 13, 2010 at 4:47 PM
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| | Preparation of the acellular scaffold of the spinal cord and the study of biocompatibility. Spinal Cord. 2010 Jan 12; Authors: Guo SZ, Ren XJ, Wu B, Jiang T Study design:Acellular spinal cord was prepared through chemical extraction, and its biocompatibility was studied.Objective:Acellular scaffolds have been developed from various materials for tissue reconstruction, except for spinal cord. The objective of this study was to prepare acellular spinal cord and examine the biocompatibility of the scaffold.Setting:This study was conducted at the Department of Orthopedics, Xinqiao Hospital, The Third Military Medical University, Chongqing, China.Methods:The morphology of the acellular segments was revealed by scanning electron microscopy, immunohistochemistry, and hematoxylin and eosin stain. Biocompatibility was studied by immunohistochemistry.Results:Results show that in spinal cord scaffolds, cells, myelin sheath and axon of nerve fibers were eliminated, and three-dimensional supports of extracellular matrix were reserved. The component analytical results of the acellular spinal cord indicate that they contain laminin,! fibronectin and collagen, which can facilitate and induce the regeneration of injured nerves, and enhance the adhesion and proliferation of cells. The acellular spinal cord has a three-dimensional structure and excellent biocompatibility.Conclusion:Our data indicate that acellular spinal cord has certain biological properties and it may be a potential alternative scaffold for spinal cord tissue engineering.Spinal Cord advance online publication, 12 January 2010; doi:10.1038/sc.2009.170. PMID: 20065987 [PubMed - as supplied by publisher] | | |
| Controlled drug release from biodegradable thermoresponsive physical hydrogel nanofibers.
January 13, 2010 at 4:47 PM
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| | Controlled drug release from biodegradable thermoresponsive physical hydrogel nanofibers. J Control Release. 2010 Jan 8; Authors: Loh XJ, Peh P, Liao S, Sng C, Li J Hydrogel nanofiber mats based on thermoresponsive multiblock poly(ester urethane)s comprising poly(ethylene glycol) (PEG), poly(propylene glycol) (PPG), and poly(epsilon-caprolactone) (PCL) segments were fabricated by electrospinning. The hydrogel nanofiber mats were more water absorbent under cold conditions and shrunk when exposed to higher temperatures. The rate of protein release could be controlled by changing the temperature of the nanofiber environment. Cell culture studies on the nanofiber mats were carried out using human dermal fibroblasts, and healthy cell morphology was observed. The adherent viable cells were quantified by MTS after rinsing in excess buffer solution. The results showed that these nanofiber scaffolds supported excellent cell adhesion, comparable with the pure PCL nanofibers. The increased hydrophilicity of these hydrogel nanofiber mats led to a more rapid hydrolytic degradation, compared with the pure PCL nanofiber mats. These hydrogel! nanofiber scaffolds could potentially be used as thermoresponsive biodegradable supporting structures for skin tissue engineering applications. PMID: 20064568 [PubMed - as supplied by publisher] | | |
| Hepatogenesis of Adipose-Derived Stem Cells on Poly-Lactide-Co-Glycolide Scaffolds: In vitro and In vivo Studies.
January 13, 2010 at 4:47 PM
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| | Hepatogenesis of Adipose-Derived Stem Cells on Poly-Lactide-Co-Glycolide Scaffolds: In vitro and In vivo Studies. Tissue Eng Part C Methods. 2010 Jan 11; Authors: Wang M, Pei H, Zhang L, Guan L, Zhang R, Jia Y, Li B, Yue W, Wang Y, Pei X Human adipose-derived stem cells (hASCs) have been shown to be multipotent and could be induced into various cell types, which make them the ideal cell source for cell therapy or tissue engineering. However, differentiation of ASCs into hepatocytes on three-dimensional scaffold, an important part of tissue engineering, has not been reported. In this study, to investigate the hepatogenesis of ASCs on porous poly-lactide-co-glycolide (PLGA) scaffolds, we loaded hASCs on these scaffolds. The cell-scaffold complex was implanted into the peritoneal cavity of 70% hepatectomized rats with or without 14 days of induction in hepatic inducing medium. Our results indicated that hASCs cultured on the PLGA scaffolds in the hepatic inducing medium proliferated more efficiently and could be induced into cells with hepatocyte-like phenotypic and functional properties. Ex vivo studies showed that induced hASCs on PLGA scaffolds survived and maintained hepatic phenotype and functio! n for at least 14 days after implantation, more over, non-induced hASCs on PLGA scaffolds expressed human albumin 14 days after transplantation. Collectively, these results suggest that porous PLGA scaffolds are suitable for the hepatogenesis of hASCs. These findings might be helpful in the application of hASCs-based tissue engineering for liver disease therapy. PMID: 20064016 [PubMed - as supplied by publisher] | | |
| Effects of Matrix Composition, Microstructure, and Viscoelasticity on the Behaviors of Vocal Fold Fibroblasts Cultured in Three-Dimensional Hydrogel Networks.
January 13, 2010 at 4:47 PM
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| | Effects of Matrix Composition, Microstructure, and Viscoelasticity on the Behaviors of Vocal Fold Fibroblasts Cultured in Three-Dimensional Hydrogel Networks. Tissue Eng Part A. 2010 Jan 11; Authors: Farran AJ, Teller SS, Jha AK, Jiao T, Hule RA, Clifton RJ, Pochan DP, Duncan RL, Jia X Vocal fold diseases and disorders are difficult to treat surgically or therapeutically. Tissue engineering offers an alternative strategy for the restoration of functional vocal folds. As a first step toward vocal fold tissue engineering, we investigated the responses of primary vocal fold fibroblasts (PVFFs) to two types of collagen and hyaluronic acid (HA)-based hydrogels that are compositionally similar, but structurally variable and mechanically different. Type A hydrogels were composed of mature collagen fibers reinforced by oxidized HA, whereas type B hydrogels contained immature collagen fibrils interpenetrated in an amorphous, covalently cross-linked HA matrix. PVFFs encapsulated in either matrix adopted a fibroblastic morphology and expressed genes related to important extracellular matrix proteins. DNA analysis indicated a linear growth profile for cells encapsulated in type B gels from day 0 to 21, in contrast to an initial dormant, nonproliferative per! iod from day 0 to 3 experienced by cells in type A gels. At the end of the culture, similar DNA content was detected in both types of constructs. A reduction in collagen content was observed for both types of constructs after 28 days of culture, with type A constructs generally retaining higher amounts of collagen than type B constructs. The HA content in the constructs decreased steadily throughout the culture, with type A constructs consistently exhibiting less HA than type B constructs. Using the torsional wave analysis, we found that the elastic moduli for type A constructs decreased sharply during the first week of culture, followed by 2 weeks of matrix stabilization without significant changes in matrix stiffness. Conversely, the elastic modulus for type B constructs increased moderately over time. It is postulated that PVFFs residing in gels alter the matrix organization, chemical compositions, and viscoelasticity through cell-mediated remodeling processes. PMID: 20064012 [PubMed - as supplied by publisher] | | |
| Initiation and progression of axonopathy in experimental autoimmune encephalomyelitis.
January 13, 2010 at 4:47 PM
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| | Initiation and progression of axonopathy in experimental autoimmune encephalomyelitis. J Neurosci. 2009 Nov 25;29(47):14965-79 Authors: Soulika AM, Lee E, McCauley E, Miers L, Bannerman P, Pleasure D Axonal loss is the principal cause of chronic disability in multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). In C57BL/6 mice with EAE induced by immunization with myelin oligodendrocyte glycoprotein peptide 35-55, the first evidences of axonal damage in spinal cord were in acute subpial and perivascular foci of infiltrating neutrophils and lymphocytes and included intra-axonal accumulations of the endovesicular Toll-like receptor TLR8, and the inflammasome protein NAcht leucine-rich repeat protein 1 (NALP1). Later in the course of this illness, focal inflammatory infiltrates disappeared from the spinal cord, but there was persistent activation of spinal cord innate immunity and progressive, bilaterally symmetric loss of small-diameter corticospinal tract axons. These results support the hypothesis that both contact-dependent and paracrine interactions of systemic inflammatory cells with axons and an innate immune-mediated neurodegenerative p! rocess contribute to axonal loss in this multiple sclerosis model. PMID: 19940192 [PubMed - indexed for MEDLINE] | | |
| Botulinum toxin enhances the implantation effect of adipocytes in C57/BL6 mice.
January 13, 2010 at 4:47 PM
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| | Botulinum toxin enhances the implantation effect of adipocytes in C57/BL6 mice. Aesthetic Plast Surg. 2009 Sep;33(5):722-9 Authors: Jung MK, Song SB, Cheon SY, Park Y, Park H, Kim C, Cho BJ, Lee WJ, Bang JW, Bang SI, Cho D BACKGROUND: Recently, many plastic surgeons have been using adipogenic-differentiated cell implantation for remodeling scars in patients. However, this technique is not a long-term solution because implanted cells disappear gradually. Therefore, we investigated a method to increase the grafted cell preservation rate by using an effective adjuvant, botulinum toxin. METHODS: The adipogenic-differentiated cells were subcutaneously injected in the dorsal area of C57/BL6 mice with or without botulinum toxin. Two and six weeks later we analyzed the residual volume and confirmed the characteristics of the implanted cells by real-time RT-PCR and immunohistochemistry. RESULTS: Two and six weeks after transplantation we found that the residual volume of the transplantation site was higher in the botulinum toxin-treated group than in the untreated group. We also confirmed that the residual transplanted area has characteristics of adipogenic tissue by histological analysis. N! ext, to determine the mechanism related to the enhanced preservation rate of grafted cells via treatment with botulinum toxin, we performed immunohistochemical staining for the angiogenesis-related marker CD31. We found that CD31 expression was higher in the botulinum toxin-treated group than in the untreated group. CONCLUSION: We have shown that in vivo grafted adipocyte cell preservation can be enhanced by treatment with botulinum toxin as an adjuvant. We suggest that botulinum toxin further increases this graft preservation rate by enhancing angiogenesis. PMID: 19626359 [PubMed - indexed for MEDLINE] | | |
| ABCB1 is predominantly expressed in human fetal neural stem/progenitor cells at an early development stage.
January 13, 2010 at 4:47 PM
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| | ABCB1 is predominantly expressed in human fetal neural stem/progenitor cells at an early development stage. J Neurosci Res. 2009 Sep;87(12):2615-23 Authors: Yamamoto A, Shofuda T, Islam MO, Nakamura Y, Yamasaki M, Okano H, Kanemura Y ABCB1 is a human ABC transporter originally characterized by its ability to cause resistance to chemotherapy drugs in cancer cells, and later found to be functionally expressed in human neural stem/progenitor cells (NSPCs) in vitro. Here, we performed a detailed examination of ABCB1's expression on human NSPCs in vitro and in human fetal brain tissues, and analyzed the cellular properties of the human NSPCs expressing ABCB1. We confirmed that ABCB1 was expressed on the surface of human NSPCs, and its level correlated well with those of Nestin and CD133. The population of fluorescence-activated cell sorter-sorted human NSPCs expressing high levels of ABCB1 showed enrichment of proliferating cells, higher expression of 246 genes (e.g., RGS6, IGFBP7, GFAP, TNC, Hes1), and lower expression of 71 genes (e.g., STMN2, DLX5, BASP1, DCX, CD24) compared with human NSPCs expressing low or no ABCB1. In situ, ABCB1 was selectively expressed in cells in the ventricular or subve! ntricular regions of lateral ventricles that expressed Nestin in human development. These findings suggest that ABCB1 is predominantly expressed in immature human fetal NSPCs in vitro and at early developmental stages in vivo, and that it may be a useful marker for human NSPCs. PMID: 19384922 [PubMed - indexed for MEDLINE] | | | |
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