2/10 pubmed: "regenerative medici...

Please add updates@feedmyinbox.com to your address book to make sure you receive these messages in the future. pubmed: "regenerative medici... Temporal dynamics of myelination in the zebrafish spinal cord. February 9, 2010 at 6:14 AM Temporal dynamics of myelination in the zebrafish spinal cord. Glia. 2010 Feb 5; Authors: Buckley CE, Marguerie A, Alderton WK, Franklin RJ Knowledge of the precise timing of myelination is critical to the success of zebrafish-based in vivo screening strategies for potential remyelination therapies. This study provides a systematic review of the timing of myelination in the zebrafish spinal cord and a critique of techniques by which it may be accurately assessed. The onset of myelination was found to be 3 days postfertilization (d.p.f.); earlier than previously reported. This coincided with the dorsal migration and differentiation of oligodendrocytes and the expression of myelin basic protein (Mbp) transcripts and protein. Our data suggests that immunohistochemistry with zebrafish-specific anti-Mbp from 3 d.p.f. is the optimal histological method for myelin visualization, while quantification of myelination is more reliably achieved by quantitative polymerase chain reaction (qPCR) for mbp from 5 d.p.f.. Transgenic fluorescent lines such as olig2:EGFP can be used to assess oligodendrocyte cell number a! t 3 d.p.f. and the development of new, more specific lines may enable real time visualization of myelin itself. Quantitative ultrastructural analysis revealed that the myelination of zebrafish axons is regulated according to axonal growth and not absolute axonal size. This study confirms the use of the zebrafish larvae as a versatile and efficient in vivo model of myelination and provides a platform on which future myelination screening studies can be based. (c) 2010 Wiley-Liss, Inc. PMID: 20140960 [PubMed - as supplied by publisher]   Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects. February 9, 2010 at 6:14 AM Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects. J Orthop Res. 2010 Feb 5; Authors: Pei M, Yan Z, Shoukry M, Boyce BM The use of xenogeneic tissues offers many advantages with respect to availability, quality control, and timing of tissue harvest. Our previous study indicated that implantation of premature tissue constructs from allogeneic synovium-derived stem cells (SDSCs) facilitated cartilage tissue regeneration. The present study investigated the feasibility of xenoimplantation of SDSC-based premature tissue constructs for the repair of osteochondral defects. Porcine SDSCs were mixed with fibrin gel, seeded in polyglycolic acid (PGA) scaffolds, and cultured in a rotating bioreactor system supplemented for 1 month with growth factor cocktails. The engineered porcine premature tissues were implanted to repair surgically induced osteochondral defects in the medial femoral condyles of 12 rabbits. Three weeks after surgery, the xenoimplantation group exhibited a smooth, whitish surface while the untreated control remained empty. Surprisingly, 6 months after surgery, the xenoimpla! ntation group displayed some tissue loss while the untreated control group was overgrown with fibrocartilage tissue. In the xenoimplantation group, chronic inflammation was observed in synovial tissue where porcine major histocompatibility complex (MHC) class II antigen positively stained in the engulfed foreign bodies. In addition, porcine source cells also migrated from the implantation site and may have been responsible for the observed loss of glycosaminoglycans (GAGs) underneath surrounding articular cartilage. The histological score was much worse in the xenoimplanted group than in the untreated control. Our study suggested that SDSC-based xenogeneic tissue constructs might cause delayed immune rejection. Xenotransplantation may not be an appropriate approach to repair osteochondral defects. (c) 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20140938 [PubMed - as supplied by publisher]   Biocompatibility of individually designed scaffolds with human periosteum for use in tissue engineering. February 9, 2010 at 6:14 AM Biocompatibility of individually designed scaffolds with human periosteum for use in tissue engineering. J Mater Sci Mater Med. 2010 Feb 7; Authors: Becker ST, Douglas T, Acil Y, Seitz H, Sivananthan S, Wiltfang J, Warnke PH The aim of this study was to evaluate and compare the biocompatibility of computer-assisted designed (CAD) synthetic hydroxyapatite (HA) and tricalciumphosphate (TCP) blocks and natural bovine hydroxyapatite blocks for augmentations and endocultivation by supporting and promoting the proliferation of human periosteal cells. Human periosteum cells were cultured using an osteogenic medium consisting of Dulbecco's modified Eagle medium supplemented with fetal calf serum, Penicillin, Streptomycin and ascorbic acid at 37 degrees C with 5% CO(2). Three scaffolds were tested: 3D-printed HA, 3D-printed TCP and bovine HA. Cell vitality was assessed by Fluorescein Diacetate (FDA) and Propidium Iodide (PI) staining, biocompatibility with LDH, MTT, WST and BrdU tests, and scanning electron microscopy. Data were analyzed with ANOVAs. Results: After 24 h all samples showed viable periosteal cells, mixed with some dead cells for the bovine HA group and very few dead cells for th! e printed HA and TCP groups. The biocompatibility tests revealed that proliferation on all scaffolds after treatment with eluate was sometimes even higher than controls. Scanning electron microscopy showed that periosteal cells formed layers covering the surfaces of all scaffolds 7 days after seeding. Conclusion: It can be concluded from our data that the tested materials are biocompatible for periosteal cells and thus can be used as scaffolds to augment bone using tissue engineering methods. PMID: 20140699 [PubMed - as supplied by publisher]   From Cellular Mechanotransduction to Biologically Inspired Engineering : 2009 Pritzker Award Lecture, BMES Annual Meeting October 10, 2009. February 9, 2010 at 6:14 AM From Cellular Mechanotransduction to Biologically Inspired Engineering : 2009 Pritzker Award Lecture, BMES Annual Meeting October 10, 2009. Ann Biomed Eng. 2010 Feb 6; Authors: Ingber DE This article is based on a lecture I presented as the recipient of the 2009 Pritzker Distinguished Lecturer Award at the Biomedical Engineering Society annual meeting in October 2009. Here, I review more than thirty years of research from my laboratory, beginning with studies designed to test the theory that cells use tensegrity (tensional integrity) architecture to stabilize their shape and sense mechanical signals, which I believed to be critical for control of cell function and tissue development. Although I was trained as a cell biologist, I found that the tools I had at my disposal were insufficient to experimentally test these theories, and thus I ventured into engineering to find critical solutions. This path has been extremely fruitful as it has led to confirmation of the critical role that physical forces play in developmental control, as well as how cells sense and respond to mechanical signals at the molecular level through a process known as cellular m! echanotransduction. Many of the predictions of the cellular tensegrity model relating to cell mechanical behaviors have been shown to be valid, and this vision of cell structure led to discovery of the central role that transmembrane adhesion receptors, such as integrins, and the cytoskeleton play in mechanosensing and mechanochemical conversion. In addition, these fundamental studies have led to significant unexpected technology fallout, including development of micromagnetic actuators for non-invasive control of cellular signaling, microfluidic systems as therapeutic extracorporeal devices for sepsis therapy, and new DNA-based nanobiotechnology approaches that permit construction of artificial tensegrities that mimic properties of living materials for applications in tissue engineering and regenerative medicine. PMID: 20140519 [PubMed - as supplied by publisher]   Tooth regeneration: Current status. February 9, 2010 at 6:14 AM Tooth regeneration: Current status. Indian J Dent Res. 2009 Oct-Dec;20(4):506-7 Authors: Dadu SS Regeneration of a functional tooth has the potential to be a promising therapeutic strategy. Experiments have shown that with the use of principles of bioengineering along with adult stem cells, scaffold material, and signaling molecules, tooth regeneration is possible. Research work is in progress on creating a viable bioroot with all its support. A new culture needs to be created that can possibly provide all the nutrients to the stem cells. With the ongoing research, tissue engineering is likely to revolutionize dental health and well-being of people by regenerating teeth over the next decade. PMID: 20139582 [PubMed - in process]   CCN3 Inhibits Neointimal Hyperplasia Through Modulation of Smooth Muscle Cell Growth and Migration. February 9, 2010 at 6:14 AM CCN3 Inhibits Neointimal Hyperplasia Through Modulation of Smooth Muscle Cell Growth and Migration. Arterioscler Thromb Vasc Biol. 2010 Feb 5; Authors: Shimoyama T, Hiraoka S, Takemoto M, Koshizaka M, Tokuyama H, Tokuyama T, Watanabe A, Fujimoto M, Kawamura H, Sato S, Tsurutani Y, Saito Y, Perbal B, Koseki H, Yokote K OBJECTIVE: CCN3 belongs to the CCN family, which constitutes multifunctional secreted proteins that act as matrix cellular regulators. We investigated the pathophysiological roles of CCN3 in the vessels. METHODS AND RESULTS: We examined the effects of CCN3 on the proliferation and migration of rat vascular smooth muscle cells (VSMC). CCN3 knockout mice were created, and vascular phenotypes and neointimal hyperplasia induced by photochemically induced thrombosis were investigated. CCN3 suppressed the VSMC proliferation induced by fetal bovine serum. The neutralizing antibody for transforming growth factor-beta did not affect the growth inhibitory effect of CCN3. Moreover, CCN3 enhanced the mRNA expression of cyclin-dependent kinase inhibitors, p21 and p15. Gamma secretase inhibitor, an inhibitor of Notch signaling, partially inhibited the enhanced expression of p21 induced by CCN3. CCN3 also inhibited the VSMC migration. Finally, the histopathologic evaluation of t! he arteries 21 days after the endothelial injury revealed a 6-fold enhancement of neointimal thickening in the null mice compared with the wild-type mice. CONCLUSIONS: CCN3 suppresses neointimal thickening through the inhibition of VSMC migration and proliferation. Our findings indicate the involvement of CCN3 in vascular homeostasis, especially on injury, and the potential usefulness of this molecule in the modulation of atherosclerotic vascular disease. PMID: 20139355 [PubMed - as supplied by publisher]   Generation of human induced pluripotent stem cells from umbilical cord matrix and amniotic membrane mesenchymal cells. February 9, 2010 at 6:14 AM Generation of human induced pluripotent stem cells from umbilical cord matrix and amniotic membrane mesenchymal cells. J Biol Chem. 2010 Feb 5; Authors: Cai J, Li W, Su H, Qin D, Yang J, Zhu F, Xu J, He W, Guo H, Labuda K, Peterbauer A, Wolbank S, Zhong M, Li Z, Wu W, So KF, Redl H, Zeng L, Esteban MA, Pei D The umbilical cord and placenta are extraembryonic tissues of particular interest for regenerative medicine. They share an early developmental origin and are source of vast amounts of cells with multi-lineage differentiation potential that are poorly immunogenic and exempt of controversy. Here we report the efficient nuclear reprogramming using exogenous factors of mesenchymal cells from placental chorionic and amniotic membranes and the umbilical cord. Induced pluripotent stem cells (iPSC) from all 3 sources homogeneously showed human embryonic stem cell (ESC)-like characteristics including morphology, normal karyotype, positive staining for alkaline phosphatase, and high expression levels of ESC-like markers (including Nanog, Rex1, Oct4, TRA-1-60, TRA-1-80, SSEA-3, and SSEA-4). Selected iPSC also formed teratomas composed of the 3 germ layers and readily produced functional motorneurons upon induced differentiation. We conclude that the umbilical cord and placen! ta can be used to produce high quality iPSC. These cell lines may prove useful to compare the epigenetic modifications, differentiation ability, and stability of the resulting lineages, between iPSC derived from multiple tissues. PMID: 20139068 [PubMed - as supplied by publisher]   RNA interference by nanofiber-based siRNA delivery system. February 9, 2010 at 6:14 AM RNA interference by nanofiber-based siRNA delivery system. J Control Release. 2010 Feb 4; Authors: Cao H, Jiang X, Chai C, Chew SY SiRNA delivery has found useful applications particularly as therapeutic agents against genetic diseases. Currently, the delivery of siRNA typically takes the form of nanoparticles. In order to expand the applications of these potent but labile molecules for long-term use required by tissue engineering and regenerative medicine, alternative delivery vehicles are required. This work presents a scaffold-mediated approach to siRNA delivery. By encapsulating siRNA within polycaprolactone (PCL) nanofibers (300-400nm in diameter) controlled release of intact siRNA could be achieved for at least 28days under physiological conditions. The successful transfection of HEK 293 cells with GAPDH siRNA released from fibrous scaffolds at day 5, 15 and 30 demonstrated that the encapsulated molecules remained bioactive throughout the period of sustained release, providing silencing efficiency of 61-81% that was comparable to conventional siRNA transfection. Direct seeding of cells ! on these biofunctional scaffolds, with and without transfection reagent, demonstrated enhanced cellular uptake and efficient GAPDH gene-silencing. This work demonstrates the potential of nanofibrous scaffold-mediated siRNA delivery for long-term gene-silencing applications. The combination of topographical features provided by nanofibrous scaffolds may provide synergistic contact guidance and biochemical signals to mediate and support cellular development in regenerative medicine. PMID: 20138939 [PubMed - as supplied by publisher]   Functionalization of poly(amidoamine) denfcdrimers with hydrophobic chains for improved gene delivery in mesenchymal stem cells. February 9, 2010 at 6:14 AM Functionalization of poly(amidoamine) denfcdrimers with hydrophobic chains for improved gene delivery in mesenchymal stem cells. J Control Release. 2010 Feb 4; Authors: Santos JL, Oliveira H, Pandita D, Rodrigues J, Pêgo AP, Granja PL, Tomás H A new family of gene delivery vectors is synthesized consisting of a medium-size generation PAMAM dendrimer (generation 5, with amine termini) core randomly linked at the periphery to hydrophobic chains that vary in length (12 to 16 carbon alkyl chains) and number (from 4.2 to 9.7 in average). The idea subjacent to the present work is to join the advantages of the cationic nature of the dendrimer with the capacity of lipids to interact with biological membranes. Unlike other amphiphilic systems designed for the same purpose, where the hydrophobic and hydrophilic moieties coexist in opposite sides, the present vectors have a hydrophilic interior and a hydrophobic corona. The vectors are characterized in respect to their ability to neutralize, bind and compact plasmid DNA (pDNA). The complexes formed between the vectors and pDNA are analyzed concerning their size, zeta-potential, resistance to serum nucleases, capacity of being internalized by cells and transfection! efficiency. These new vectors show a remarkable capacity for mediating the internalization of pDNA with minimum cytotoxicity, being this effect positively correlated with the -CH(2)- content present in the hydrophobic corona. Gene expression in MSCs, a cell type with relevancy in the regenerative medicine clinical context, is also enhanced using the new vectors but, in this case, the higher efficiency is shown by the vectors containing the smallest hydrophobic chains. PMID: 20138937 [PubMed - as supplied by publisher]   Human gingiva derived mesenchymal stem cells are superior to bone marrow derived mesenchymal stem cells for cell therapy in regenerative medicine. February 9, 2010 at 6:14 AM Human gingiva derived mesenchymal stem cells are superior to bone marrow derived mesenchymal stem cells for cell therapy in regenerative medicine. Biochem Biophys Res Commun. 2010 Feb 4; Authors: Tomar GB, Srivastava RK, Gupta N, Barhanpurkar AP, Pote ST, Jhaveri HM, Mishra GC, Wani MR Mesenchymal stem cells (MSCs) are capable of self-renewal and differentiation into multiple cell lineages. Presently, bone marrow is considered as a prime source of MSCs; however, there are some drawbacks and limitations in use of these MSCs for cell therapy. In this study, we demonstrate that human gingival tissue-derived MSCs have several advantages over bone marrow derived MSCs. Gingival MSCs are easy to isolate, homogenous and proliferate faster than bone marrow MSCs without any growth factor. Importantly, gingival MSCs display stable morphology and do not loose MSC characteristic at higher passages. In addition, gingival MSCs maintain normal karyotype and telomerase activity in long term cultures, and are not tumorigenic. Thus, we reveal that human gingiva is a better source of MSCs than bone marrow, and large number of functionally competent clinical grade MSCs can be generated in short duration for cell therapy in regenerative medicine and tissue engineerin! g. PMID: 20138833 [PubMed - as supplied by publisher]   Bioactive hydrogels made from step-growth derived PEG-peptide macromers. February 9, 2010 at 6:14 AM Bioactive hydrogels made from step-growth derived PEG-peptide macromers. Biomaterials. 2010 Feb 5; Authors: Miller JS, Shen CJ, Legant WR, Baranski JD, Blakely BL, Chen CS Synthetic hydrogels based on poly(ethylene glycol) (PEG) have been used as biomaterials for cell biology and tissue engineering investigations. Bioactive PEG-based gels have largely relied on heterobifunctional or multi-arm PEG precursors that can be difficult to synthesize and characterize or expensive to obtain. Here, we report an alternative strategy, which instead uses inexpensive and readily available PEG precursors to simplify reactant sourcing. This new approach provides a robust system in which to probe cellular interactions with the microenvironment. We used the step-growth polymerization of PEG diacrylate (PEGDA, 3400Da) with bis-cysteine matrix metalloproteinase (MMP)-sensitive peptides via Michael-type addition to form biodegradable photoactive macromers of the form acrylate-PEG-(peptide-PEG)(m)-acrylate. The molecular weight (MW) of these macromers is controlled by the stoichiometry of the reaction, with a high proportion of resultant macromer species! greater than 500kDa. In addition, the polydispersity of these materials was nearly identical for three different MMP-sensitive peptide sequences subjected to the same reaction conditions. When photopolymerized into hydrogels, these high MW materials exhibit increased swelling and sensitivity to collagenase-mediated degradation as compared to previously published PEG hydrogel systems. Cell-adhesive acrylate-PEG-CGRGDS was synthesized similarly and its immobilization and stability in solid hydrogels was characterized with a modified Lowry assay. To illustrate the functional utility of this approach in a biological setting, we applied this system to develop materials that promote angiogenesis in an ex vivo aortic arch explant assay. We demonstrate the formation and invasion of new sprouts mediated by endothelial cells into the hydrogels from embedded embryonic chick aortic arches. Furthermore, we show that this capillary sprouting and three-dimensional migration of endothelia! l cells can be tuned by engineering the MMP-susceptibility of ! the hydr ogels and the presence of functional immobilized adhesive ligands (CGRGDS vs. CGRGES peptide). The facile chemistry described and significant cellular responses observed suggest the usefulness of these materials in a variety of in vitro and ex vivo biologic investigations, and may aid in the design or refinement of material systems for a range of tissue engineering approaches. PMID: 20138664 [PubMed - as supplied by publisher]   Morphological and mechanical characteristics of the reconstructed rat abdominal wall following use of a wet electrospun biodegradable polyurethane elastomer scaffold. February 9, 2010 at 6:14 AM Morphological and mechanical characteristics of the reconstructed rat abdominal wall following use of a wet electrospun biodegradable polyurethane elastomer scaffold. Biomaterials. 2010 Feb 5; Authors: Hashizume R, Fujimoto KL, Hong Y, Amoroso NJ, Tobita K, Miki T, Keller BB, Sacks MS, Wagner WR Although a variety of materials are currently used for abdominal wall repair, general complications encountered include herniation, infection, and mechanical mismatch with native tissue. An approach wherein a degradable synthetic material is ultimately replaced by tissue mechanically approximating the native state could obviate these complications. We report here on the generation of biodegradable scaffolds for abdominal wall replacement using a wet electrospinning technique in which fibers of a biodegradable elastomer, poly(ester urethane)urea (PEUU), were concurrently deposited with electrosprayed serum-based culture medium. Wet electrospun PEUU (wet ePEUU) was found to exhibit markedly different mechanical behavior and to possess an altered microstructure relative to dry processed ePEUU. In a rat model for abdominal wall replacement, wet ePEUU scaffolds (1x2.5cm) provided a healing result that developed toward approximating physiologic mechanical behavior at 8 ! weeks. An extensive cellular infiltrate possessing contractile smooth muscle markers was observed together with extensive extracellular matrix (collagens, elastin) elaboration. Control implants of dry ePEUU and expanded polytetrafluoroethylene did not experience substantial cellular infiltration and did not take on the native mechanical anisotropy of the rat abdominal wall. These results illustrate the markedly different in vivo behavior observed with this newly reported wet electrospinning process, offering a potentially useful refinement of an increasingly common biomaterial processing technique. PMID: 20138661 [PubMed - as supplied by publisher]   Stress response of fibroblasts adherent to the surface of plasma-treated poly(lactic-co-glycolic acid) nanofiber matrices. February 9, 2010 at 6:14 AM Stress response of fibroblasts adherent to the surface of plasma-treated poly(lactic-co-glycolic acid) nanofiber matrices. Colloids Surf B Biointerfaces. 2010 Jan 25; Authors: Park H, Lee JW, Park KE, Park WH, Lee KY Recent studies have shown that polymeric scaffolds as a synthetic extracellular matrix (ECM) are essential for regenerating tissues or organs in tissue engineering approaches. Controlling the surface functionality of polymer scaffolds is critical in regulation of cellular responses to the scaffolds during tissue formation. However, the stress response of cells to polymer scaffolds with different surface characteristics is not yet clear. We investigated the expression of heat shock protein (HSP) and Bcl-2 in fibroblasts cultured on electrospun nanofiber matrices with different surface characteristics. The hydrophilicity and chemical composition of electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers was regulated by plasma treatment in the presence of ammonia gas. We found that expression levels of HSP and Bcl-2 in fibroblasts were strongly dependent on the surface hydrophilicity and concentration of nitrogen-containing functional groups on the nanofiber mat! rices. The controlled hydrophilicity and surface chemical composition of nanofiber matrices enhanced adhesion and spreading of cells on the matrices, resulting in reduction of cellular stress. This approach to controlling the surface properties and regulating expression of a stress gene could be useful in the design of synthetic ECMs for many tissue engineering applications. PMID: 20138484 [PubMed - as supplied by publisher]   Nanotopographical modification: A regulator of cellular function through focal adhesions. February 9, 2010 at 6:14 AM Nanotopographical modification: A regulator of cellular function through focal adhesions. Nanomedicine. 2010 Feb 3; Authors: Biggs MJ, Richards RG, Dalby MJ As materials technology and the field of biomedical engineering advances, the role of cellular mechanisms, in particular adhesive interactions with implantable devices, becomes more relevant in both research and clinical practice. A key tenet of medical device design revolves around the exquisite ability of biological systems to respond to topographic features or chemical stimuli, a process which has led to the development of next-generation biomaterials for a wide variety of clinical disorders. In vitro studies have identified nanoscale features as potent modulators of cellular behaviour and the onset of focal adhesion formation. The focus of this review is on the recent developments concerning the role of nanoscale structures on integrin mediated adhesion and cellular function with an emphasis on the generation of synthetic constructs for regenerative applications. PMID: 20138244 [PubMed - as supplied by publisher]   [Experimental study on tissue engineering platelet lysates in the promotion of bone reconstruction.] February 9, 2010 at 6:14 AM [Experimental study on tissue engineering platelet lysates in the promotion of bone reconstruction.] Zhonghua Yi Xue Za Zhi. 2009 Nov;89(43):3083-3086 Authors: Song HP, Wang ZQ, Li QJ, Li BX, Bai JQ OBJECTIVE: To evaluate the effects of tissue engineered allogeneic platelet lysates (PL) upon bone reconstruction. METHODS: After preparation of recombinant material with PL, allogeneic decalcified bone granules (ADBG) and collagen type I (CG), 30 healthy Wistar rats were used to prepare the bilateral bone defects in femoral condyles. The defects were filled with equivalent PL/ADBG/CG, ADBG/CG and CG in different groups of A, B and C (with 10 rats each) respectively. At 4 weeks, the defect reconstruction was evaluated with radiology, histology, immunology and biomechanics. RESULTS: (1) The X-ray showed that bone density in group A (4.18 +/- 0.96) was close to that of normal bone and it was significantly higher than that in group B (2.36 +/- 0.87) and group C (1.09 +/- 0.55) (P < 0.01). (2) In comparisons with B and C, the histological assay revealed that there were markedly more activities of new bone formation and more implanted bone granules surviving without! significant lymphocyte infiltration, as well as more osteoclastic bone resorption in group A. The bone histomorphometric assay showed the newly formed bone area in group A (286.73 +/- 17.22) was significantly higher than that in group B (94.34 +/- 33.56) and group C (19.12 +/- 14.53) (P < 0.01). (3) Anti-press mechanical measures showed that the destructive load in A, B, C and normal control group was 259.63 +/- 34.57, 187.90 +/- 21.07, 91.33 +/- 26.58 and 311.93 +/- 82.45 respectively. The destructive energy in A, B, C and normal control group was 10.82 +/- 1.44, 7.83 +/- 0.88, 3.81 +/- 1.11 and 12.97 +/- 3.43 respectively. These results showed either destructive load or destructive energy in group A was markedly higher than that in group B and group C with significant difference (P < 0.01), but still lower than that in normal controls (P < 0.01). (4) Three-color flow cytometry assay showed that the T lymphocyte subsets of CD3+CD4+CD8-, CD3+CD8+CD4- and the ratio! of CD4/CD8 showed no significance difference within these thr! ee group s as well as normal controls. CONCLUSION: Tissue engineering PL (PL/ADBG/CG) is capable of accelerating the regenerative repair of bone defect and promoting the bone regeneration and osetointergretion of allograft bone after transplantation. PMID: 20137640 [PubMed - as supplied by publisher]   [Changes of Differentiation and Gene Expression of CD133(+) Cells in Human Umbilical Cord Blood Induced by SCF and bFGF.] February 9, 2010 at 6:14 AM [Changes of Differentiation and Gene Expression of CD133(+) Cells in Human Umbilical Cord Blood Induced by SCF and bFGF.] Zhongguo Shi Yan Xue Ye Xue Za Zhi. 2010 Jan;18(1):146-150 Authors: Zhang J, Zhu JS, Li QR, DU Y, Yang B, Li GX, Hu X This study was aimed to investigate the changes of differentiation and gene expression of CD133(+) cells in human umbilical cord blood induced by stem cell factor (SCF) and basic fibroblast growth factor (bFGF) in vitro, and to explore the biological characteristics of CD133(+) cells so as to provide experimental basis for potential use in regenerative medicine. The human umbilical cord blood CD133(+) cells were isolated from umbilical cord blood and purified by MACS magnetic selection. The CD133(+) cells were cultured in DMEM/F12 medium containing SCF, bFGF and B27 for 10 to 15 days. The total RNA of these cells was extracted before and after culture, and the analysis of related gene expression levels of these cells was performed using oligonucleotide microarrays. The results showed that out of 263 genes 21 genes were obviously up-regulated after culture than that before culture, whereas 7 genes were found to be significant down-regulated as compared with fresh-s! eparated CD133(+) cells. These genes were involved in stem cell specific markers, cell cycle regulators, stem cell differentiation markers and signaling pathways that are important for stem cell maintenance. It is concluded that SCF and bFGF can induce differentiation of human cord blood CD133(+) cells through up- or down-regulation of specific genes. This study provides gene expression information for SCF and bFGF-induced human cord blood CD133(+) cells and contributes to understand the effect of SCF and bFGF on proliferation and differentiation CD133(+) cells at gene level, and promotes therapeutic applications of the CD133(+) cells induced by SCF and bFGF. PMID: 20137136 [PubMed - as supplied by publisher]   Haplotype-specific sequencing reveals a novel HLA-A*03 allele, A*030114. February 9, 2010 at 6:14 AM Haplotype-specific sequencing reveals a novel HLA-A*03 allele, A*030114. Tissue Antigens. 2010 Feb 4; Authors: Jakubauskas A, Griskevicius L The novel allele HLA-A*030114 differs from HLA-A*03010101 by a silent nucleotide substitution at codon 153A (GCG to GCA). PMID: 20136775 [PubMed - as supplied by publisher]   Cell-Laden Hydrogel Constructs of Hyaluronic Acid, Collagen, and Laminin for Neural Tissue Engineering. February 9, 2010 at 6:14 AM Cell-Laden Hydrogel Constructs of Hyaluronic Acid, Collagen, and Laminin for Neural Tissue Engineering. Tissue Eng Part A. 2010 Feb 7; Authors: Suri S, Schmidt CE Various neural tissue engineering approaches that are under development for applications ranging from guidance conduits to cell-based therapies rely on the ability to encapsulate cells in three-dimensional (3D) scaffolds. Schwann cells play a key role in peripheral nerve regeneration by forming oriented paths for regrowing axons. We have engineered collagen and hyaluronic acid interpenetrating polymer network (IPN) hydrogels with and without laminin as a 3D culture system for Schwann cells in an attempt to devise novel neural regeneration therapies. Encapsulation of Schwann cells in 3D hydrogel constructs did not affect cell viability and cells were viable for 2 weeks in all hydrogel samples. Moreover, in hydrogels with high cell density, cells underwent spreading and proliferation, and the cell numbers increased by day 14 as assessed qualitatively using a Live/dead((R)) assay and scanning electron microscopy (SEM), and quantitatively using a CellTiter((R)) 96 AQu! eous non-radioactive cell proliferation assay. In some cases, the cells aligned parallel to each other and formed structures reminiscent of Bands of Büngner. Schwann cells in cell-hydrogel constructs with high cell density were not only viable but also actively secreting nerve growth factor and brain-derived neurotrophic factor. Of particular importance was the observation that addition of laminin in these hydrogels increased the overall production of nerve growth factor and brain-derived neurotrophic factor from the cells. Immunostaining revealed that S100 expression and cell spreading were differentially affected by cell density. Interestingly, in the co-culture of dissociated neurons with Schwann cells, neurons were able to extend neurites and some neurites were observed to follow Schwann cells. Therefore, we conclude that Schwann cells encapsulated in the 3D extracellular matrix-mimicking hydrogel may hold promise in nerve regeneration therapies and may form the ba! sis for understanding the underlying mechanisms of Schwann cel! l intera ctions with neurons and various extracellular matrix components. PMID: 20136524 [PubMed - as supplied by publisher]   Human Embryonic Mesodermal Progenitors Highly Resemble Human Mesenchymal Stem Cells and Display High Potential for Tissue Engineering Applications. February 9, 2010 at 6:14 AM Human Embryonic Mesodermal Progenitors Highly Resemble Human Mesenchymal Stem Cells and Display High Potential for Tissue Engineering Applications. Tissue Eng Part A. 2010 Feb 5; Authors: de Peppo GM, Svensson S, Lennerås M, Synnergren J, Stenberg J, Strehl R, Hyllner J, Thomsen P, Karlsson C Adult stem cells, such as human mesenchymal stem cells (hMSCs), show limited proliferative capacity and, after long-term culture, lose their differentiation capacity and are therefore not an optimal cell source for tissue engineering. Human embryonic stem cells (hESCs) constitute an important new resource in this field, but one major drawback is the risk of tumor formation in the recipients. One alternative is to use progenitor cells derived from hESCs which are more lineage restricted but do not form teratomas. We have recently derived a cell line from hESCs denoted human embryonic stem cell-derived mesodermal progenitors (hES-MPs) and here, using genome wide microarray analysis, report that the process of hES-MPs derivation results in a significantly altered expression of hESCs characteristic genes to an expression level highly similar to that of hMSCs. However, hES-MPs displayed a significantly higher proliferative capacity and longer telomeres. Interestingly, ! the hES-MPs also demonstrated a lower expression of HLA class II proteins before and after interferon-gamma treatment, indicating that these cells may somewhat be immunoprivileged and potentially used for HLA-incompatible transplantation. The hES-MPs are thus an appealing alternative to hMSCs in tissue engineering applications and stem cell-based therapies for mesodermal tissues. PMID: 20136402 [PubMed - as supplied by publisher]   [Effect of acellular process on small intestinal submucosa cell residue and growth factor content] February 9, 2010 at 6:14 AM [Effect of acellular process on small intestinal submucosa cell residue and growth factor content] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Jan;24(1):94-9 Authors: Chen W, Li C, Wu S, Xie H, Luo J OBJECTIVE: To investigate the effect of machine-enzyme digestion method on the residual quantity of small intestinal submucosa (SIS) cell and the content of growth factors. METHODS: Fresh jejunum of pig within 4 hours after harvesting was prepared into SIS after machine digestion (removing placenta percreta, mucosa, and muscular layer), degrease, trypsinization, abstergent processing, and freeze drying. Samples were kept after every preparation step serving as groups A, B, C, D, and E, respectively (n=4 per group). And the fresh jejunum served as control group (group F, n=4). The histological alteration in each preparation process was reviewed with HE staining and scanning electron microscope (SEM). Nest-polymerase chain reaction (PCR) was used to determine the content of death associated protein 12 (DAP12), and enzyme-linked immunosorbent assay (ELISA) was applied to detect the content of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (! bFGF), transforming growth factor beta (TGF-beta), tumor necrosis factor alpha (TNF-alpha). RESULTS: HE staining and SEM observation showed that there were residual cells in groups A and B, and there were no residual cells in groups C, D, and E. Nest-PCR test revealed the occurrence of DAP12 in each group. The contents of DAP12 in groups A, B, C, D, E, and F were (18.01 +/- 9.53), (11.87 +/- 2.35), (0.59 +/- 0.27), (0.29 +/- 0.05), (0.19 +/- 0.04), and (183.50 +/- 120.13) copy x 10(6)/cm2. The content of DAP12 in group F was significant higher than that of other groups (P < 0.05), groups A and B was higher than groups C, D, and E (P < 0.05), there were significant differences among groups C, D, and E (P < 0.05), and there was no significant difference between groups A and B (P > 0.05). The ELISA test showed the content of VEGF, bFGF, TGF-beta, and TNF-alpha in group A was significantly higher than that of groups B, C, D, and E (P < 0.05), and there was no sig! nificant difference among groups B, C, D, and E (P > 0.05).! CONCLUS ION: SIS prepared by simple mechanical method has more residual cells, while the machine-enzyme digestion method can effectively remove the cells and significantly reduce the DAP12 content. This approach can not obviously reduce the growth factor content in SIS. PMID: 20135981 [PubMed - in process]   Farnesyl pyrophosphate inhibits epithelialization and wound healing through the glucocorticoid receptor. February 9, 2010 at 6:14 AM Related Articles Farnesyl pyrophosphate inhibits epithelialization and wound healing through the glucocorticoid receptor. J Biol Chem. 2010 Jan 15;285(3):1980-8 Authors: Vukelic S, Stojadinovic O, Pastar I, Vouthounis C, Krzyzanowska A, Das S, Samuels HH, Tomic-Canic M Farnesyl pyrophosphate (FPP), a key intermediate in the mevalonate pathway and protein farnesylation, can act as an agonist for several nuclear hormone receptors. Here we show a novel mechanism by which FPP inhibits wound healing acting as an agonist for glucocorticoid receptor (GR). Elevation of endogenous FPP by the squalene synthetase inhibitor zaragozic acid A (ZGA) or addition of FPP to the cell culture medium results in activation and nuclear translocation of the GR, a known wound healing inhibitor. We used functional studies to evaluate the effects of FPP on wound healing. Both FPP and ZGA inhibited keratinocyte migration and epithelialization in vitro and ex vivo. These effects were independent of farnesylation and indicate that modulation of FPP levels in skin may be beneficial for wound healing. FPP inhibition of keratinocyte migration and wound healing proceeds, in part, by repression of the keratin 6 gene. Furthermore, we show that the 3-hydroxy-3-meth! ylglutaryl-CoA-reductase inhibitor mevastatin, which blocks FPP formation, not only promotes epithelialization in acute wounds but also reverses the effect of ZGA on activation of the GR and inhibition of epithelialization. We conclude that FPP inhibits wound healing by acting as a GR agonist. Of special interest is that FPP is naturally present in cells prior to glucocorticoid synthesis and that FPP levels can be further altered by the statins. Therefore, our findings may provide a better understanding of the pleiotropic effects of statins as well as molecular mechanisms by which they may accelerate wound healing. PMID: 19903814 [PubMed - indexed for MEDLINE]   How does inflammation cause Barrett's metaplasia? February 9, 2010 at 6:14 AM Related Articles How does inflammation cause Barrett's metaplasia? Curr Opin Pharmacol. 2009 Dec;9(6):721-6 Authors: Colleypriest BJ, Ward SG, Tosh D Oesophageal adenocarcinoma conveys a poor prognosis and has a rapidly increasing incidence. Similarly, Barrett's metaplasia (a precursor lesion for oesophageal adenocarcinoma) has an increasing incidence. Both oesophageal adenocarcinoma and Barrett's metaplasia are more common in the context of inflammation as a result of acid and bile reflux. The cytokine profile of Barrett's metaplasia is predominantly a T-helper 2 response that contrasts with the T-helper 1 response in normal and inflamed oesophagus and normal intestine. A key transcription factor in the development of Barrett's metaplasia, CDX2, has recently been shown to be induced in response to inflammatory mediators. The mechanism for induction of CDX2 is dependent on nuclear factor kappa B, a crucial transcription factor in the inflammatory response. Understanding the role of oesophageal inflammation will provide important insight into the development of Barrett's metaplasia and oesophageal cancer. PMID: 19828375 [PubMed - indexed for MEDLINE]   This email was sent to agupta1213+termsc@gmail.com.  Account Login Don't want to receive this feed any longer? Unsubscribe here This email was carefully delivered by Feed My Inbox. 230 Franklin Road Suite 814 Franklin, TN 37064