| Potential role of dental stem cells in the cellular therapy of cerebral ischemia.
November 26, 2009 at 10:12 am
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| | Potential role of dental stem cells in the cellular therapy of cerebral ischemia. Curr Pharm Des. 2009;15(33):3908-16 Authors: Yalvac ME, Rizvanov AA, Kilic E, Sahin F, Mukhamedyarov MA, Islamov RR, Palotás A Stem cell based therapies for cerebral ischemia (CI) utilize different cell sources including embryonic stem cells (ESCs), neural stem cells (NSCs), umbilical cord blood cells (UCBCs), mesenchymal stem cells (MSCs), and some immortalized cell lines. To date, experimental studies showed that all of these cell sources have been successful to some extent in attenuating the ischemic damage and improving functional recovery after brain injury. Bone marrow derived MSCs seem to be the most widely used and well characterized cell source, which can be also employed for autologous transplantation. Currently, there are two main theories behind the therapeutic effect of stem cell transplantation for treating CIs. The first concept is cell replacement theory in which transplanted stem cells differentiate into progenitor and specialized somatic cells to supersede dying cells. The other hypothesis is based on immuno-modulatory, neuro-protective and neuro-trophic abilities of stem cells which help reducing stroke size and increasing the recovery of behavioral functions. Recent studies focusing on alternative stem cell sources have revealed that dental stem cells (DSCs), including dental pulp stem cells (DPSCs) and dental follicle cells (DFCs) possess properties of MSCs and NSCs. They differentiate into neural linage cells and some other cell types such as osteocytes, adipocytes, chondrocytes, muscle cells and hepatocytes. This review is intended to examine stem cell therapy approaches for CI and emphasize potential use of DSCs as an alternative cell source for the treatment of brain ischemia. PMID: 19938343 [PubMed - in process] |
| Additive and synergistic effects of bFGF and hypoxia on leporine meniscus cell-seeded PLLA scaffolds.
November 26, 2009 at 10:12 am
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| | Additive and synergistic effects of bFGF and hypoxia on leporine meniscus cell-seeded PLLA scaffolds. J Tissue Eng Regen Med. 2009 Nov 24; Authors: Gunja NJ, Athanasiou KA Injuries to avascular regions of menisci do not heal and result in significant discomfort to patients. Current treatments, such as partial meniscectomy, alleviate these symptoms in the short term but lead to premature osteoarthritis as a result of compromised stability and changes in knee biomechanics. Thus, tissue engineering of the meniscus may provide an alternative treatment modality to overcome this problem. In this experiment, a scaffold-based tissue-engineering approach was utilized to regenerate the meniscus. Meniscus cells were cultured on poly-L-lactic acid scaffolds in normoxic ( approximately 21% oxygen) or hypoxic ( approximately 2% oxygen) conditions in the presence or absence of the growth factor, basic fibroblast growth factor (bFGF). At t = 4 weeks, histological sections of constructs showed presence of collagen and glycosaminoglycan (GAG) in all groups. Immunohistochemical staining showed the presence of collagen I in all groups and collagen II in groups cultured under hypoxic conditions. bFGF in the culture medium significantly increased cell number/construct by 25%, regardless of culture conditions. For GAG/construct, synergistic increases were observed in constructs cultured in hypoxic conditions and bFGF (two-fold) when compared to constructs cultured in normoxic conditions. Compressive tests showed synergistic increases in the relaxation modulus and coefficient of viscosity and additive increases in the instantaneous modulus for constructs cultured under hypoxic conditions and bFGF, when compared to constructs cultured under normoxic conditions. Overall, these results demonstrate that bFGF and hypoxia can significantly enhance the ability of meniscus cells to produce GAGs and improve the compressive properties of tissue-engineered meniscus constructs in vitro. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19937913 [PubMed - as supplied by publisher] |
| Enamel matrix derivative enhances tissue formation around scaffolds used for tissue engineering of ligaments.
November 26, 2009 at 10:12 am
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| | Enamel matrix derivative enhances tissue formation around scaffolds used for tissue engineering of ligaments. J Tissue Eng Regen Med. 2009 Nov 20; Authors: Messenger MP, Raïf EM, Seedhom BB, Brookes SJ The following in vitro translational study investigated whether enamel matrix derivative (EMD), an approved biomimetic treatment for periodontal disease (Emdogain((R))) and hard-to-heal wounds (Xelma((R))), enhanced synovial cell colonization and protein synthesis around a scaffold used clinically for in situ tissue engineering of the torn anterior cruciate ligament (ACL). Synovial cells were enzymatically extracted from bovine synovium and dynamically seeded onto polyethylene terephthalate (PET) scaffolds. The cells were cultured in low-serum medium (0.5% FBS) for 4 weeks with either a single administration of EMD at the start of the 4 week period or multiple administrations of EMD at regular intervals throughout the 4 weeks. Samples were harvested and evaluated using the Hoechst DNA assay, BCA protein assay, cresolphthalein complexone calcium assay, SDS-PAGE, ELISA and electron microscopy. A significant increase in cell number (DNA) (p < 0.01), protein content (p < 0.01) and TGFbeta1 synthesis (p < 0.01) was observed with multiple administrations of EMD. Additionally, SDS-PAGE showed an increase in high molecular weight proteins, characteristic of the fibril-forming collagens. Electron microscopy supported these findings, showing that scaffolds treated with multiple administrations of EMD were heavily coated with cells and extracellular matrix (ECM) that enveloped the fibres. Multiple administrations of EMD to synovial cell-seeded scaffolds enhanced the formation of tissue in vitro. Additionally, it was shown that EMD enhanced TGFbeta1 synthesis of synovial cells, suggesting a potential mode of action for EMD's capacity to stimulate tissue regeneration. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19937644 [PubMed - as supplied by publisher] |
| Investigating the importance of flow when utilizing hyaluronan scaffolds for tissue engineering.
November 26, 2009 at 10:12 am
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| | Investigating the importance of flow when utilizing hyaluronan scaffolds for tissue engineering. J Tissue Eng Regen Med. 2009 Nov 20; Authors: Donegan GC, Hunt JA, Rhodes N Esterified hyaluronan scaffolds offer significant advantages for tissue engineering. They are recognized by cellular receptors, interact with many other extracellular matrix proteins and their metabolism is mediated by intrinsic cellular pathways. In this study differences in the viability and structural integrity of vascular tissue models cultured on hyaluronan scaffolds under laminar flow conditions highlighted potential differences in the biodegradation kinetics, processes and end-products, depending on the culture environment. Critical factors are likely to include seeding densities and the duration and magnitude of applied biomechanical stress. Proteomic evaluation of the timing and amount of remodelling protein expression, the resulting biomechanical changes arising from this response and metabolic cell viability assay, together with examination of tissue morphology, were conducted in vascular tissue models cultured on esterified hyaluronan felt and PTFE mesh scaffolds. The vascular tissue models were derived using complete cell sheets derived from harvested and expanded umbilical cord vein cells. This seeding method utilizes high-density cell populations from the outset, while the cells are already supported by their own abundant extracellular matrix. Type I and type IV collagen expression in parallel with MMP-1 and MMP-2 expression were monitored in the tissue models over a 10 day culture period under laminar flow regimes using protein immobilization technologies. Uniaxial tensile testing and scanning electron microscopy were used to compare the resulting effects of hydrodynamic stimulation upon structural integrity, while viability assays were conducted to evaluate the effects of shear on metabolic function. The proteomic results showed that the hyaluronan felt-supported tissues expressed higher levels of all remodelling proteins than those cultured on PTFE mesh. Overall, a 21% greater expression of type I collagen, 24% higher levels of type IV collagen, 24% higher levels of MMP-1 and 34% more MMP-2 were observed during hydrodynamic stress. This was coupled with a loss of structural integrity in these models after the introduction of laminar flow, as compared to the increases in all mechanical properties observed in the PTFE mesh-supported tissues. However, under flow conditions, the hyaluronan-supported tissues showed some recovery of the viability originally lost during static culture conditions, in contrast to PTFE mesh-based models, where initial gains were followed by a decline in metabolic viability after applied shear stress. Proteomic, cell viability and mechanical testing data emphasized the need for extended in vitro evaluations to enable better understanding of multi-stage remodelling and reparative processes in tissues cultured on biodegradable scaffolds. This study also highlighted the possibility that in high-density tissue culture with a biodegradable component, dynamic conditions may be more conducive to optimal tissue development than the static environment because they facilitate the efficient removal of high concentrations of degradation end-products accumulating in the pericellular space. Copyright (c) 2009 John Wiley & Sons, Ltd. PMID: 19937643 [PubMed - as supplied by publisher] |
| Marginal expression of CXCR4 on c-kit(+)Sca-1 (+)Lineage (-) hematopoietic stem/progenitor cells.
November 26, 2009 at 10:12 am
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| | Marginal expression of CXCR4 on c-kit(+)Sca-1 (+)Lineage (-) hematopoietic stem/progenitor cells. Int J Hematol. 2009 Nov 26; Authors: Sasaki Y, Matsuoka Y, Hase M, Toyohara T, Murakami M, Takahashi M, Nakatsuka R, Uemura Y, Sonoda Y Stromal cell-derived factor 1 (SDF-1) and its receptor CXCR4 are the key regulatory molecules of hematopoietic stem cell (HSC) migration and engraftment to the bone marrow (BM) microenvironment. However, the significance of the ligand-receptor complex on HSC in steady-state BM is not clear. There is currently a lack of information as to how CXCR4 is expressed on HSCs. We herein demonstrate that c-kit(+)Sca-1(+)Lineage(-) (KSL) cells freshly isolated from BM expressed very low to undetectable levels of CXCR4. Two hours of incubation at 37 degrees C quickly up-modulated the receptor expression on KSL cells. Protein synthesis was not required for this early stage up-regulation, thus suggesting the emergence of intracellularly pooled receptors to the cell surface. However, protein synthesis was involved at the later stage of up-regulation. The up-regulated CXCR4 was functional, as evidenced by the fact that the incubated KSL cells more efficiently migrated to the SDF-1 gradient in vitro. Therefore, although KSL cells are able to express functional CXCR4, the receptors are only marginally expressed in the steady-state BM microenvironment. These observations therefore indicate the limited role of the SDF-1-CXCR4 axis on HSC functionality in a static BM environment. PMID: 19937482 [PubMed - as supplied by publisher] |
| Crosslinking effect of Nordihydroguaiaretic acid (NDGA) on decellularized heart valve scaffold for tissue engineering.
November 26, 2009 at 10:12 am
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| | Crosslinking effect of Nordihydroguaiaretic acid (NDGA) on decellularized heart valve scaffold for tissue engineering. J Mater Sci Mater Med. 2009 Nov 20; Authors: Lü X, Zhai W, Zhou Y, Zhou Y, Zhang H, Chang J Decellularized heart valve scaffolds possess many desirable properties in valvular tissue engineering. However, their current applications were limited by short durability, easily structural dysfunction and immunological competence. Although crosslinking with chemical reagents, such as glutaraldehyde (GA), will enhance the mechanical properties, the low long-term stability and cytotoxicity of the scaffolds remains potential problem. Nordihydroguaiaretic acid (NDGA) is a bioactive natural product which is able to crosslink collagen and was proven to be effective in preparation of scaffold for tendon tissue engineering. In this paper, NDGA crosslinked decellularized heart valve scaffolds demonstrated higher tensile strength, enzymatic hydrolysis resistance and store stability than the non-crosslinked ones. Its mechanical properties and cytocompability were superior to that of GA-crosslinked heart valve matrix. Below the concentration of 10 mug/ml, NDGA has no visible cytotoxic effect on both endothelial cells (EC) and valvular interstitial cells (VIC) and its cytotoxicity is much less than that of GA. The LC50 (50% lethal concentration) of NDGA on ECs and VICs are 32.6 mug/ml and 47.5 mug/ml, respectively, while those of GA are almost 30 times higher than NDGA (P < 0.05). ECs can attach to and maintain normal morphology on the surface of NDGA-crosslinked valvular scaffolds but not GA-crosslinked ones. This study demonstrated that NDGA-crosslinking of decellularized valvular matrix is a promising approach for preparation of heart valve tissue engineering scaffolds. PMID: 19936890 [PubMed - as supplied by publisher] |
| Tissue engineering: Function follows form.
November 26, 2009 at 10:12 am
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| | Tissue engineering: Function follows form. Nat Mater. 2009 Dec;8(12):923-924 Authors: Iatridis JC PMID: 19935690 [PubMed - as supplied by publisher] |
| Effect of Sustained-Release PDGF and TGF-beta on Cyclophosphamide-Induced Impaired Wound Healing.
November 26, 2009 at 10:12 am
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| | Effect of Sustained-Release PDGF and TGF-beta on Cyclophosphamide-Induced Impaired Wound Healing. Plast Reconstr Surg. 2009 Oct;124(4):1118-1124 Authors: Ashraf A, Lee PH, Kim K, Zaporojan V, Bonassar L, Valentini R, Spangenberger A, Weinzweig J BACKGROUND:: Proper wound healing is pivotal to successful surgical outcomes. Previous studies have shown that growth factors can be used to enhance tissue repair under impaired healing conditions. However, because of limited delivery methods, the growth factors in these studies were delivered either topically or as a single local administration. METHODS:: Sixty Sprague-Dawley rats were divided equally into five groups and served as untreated normal controls or were implanted subcutaneously with a novel sustained-release drug delivery system through a dorsal incisional wound. This system delivered either transforming growth factor (TGF)-ss alone, platelet-derived growth factor (PDGF) alone, or TGF-ss and PDGF in combination, or served as unloaded sham controls. Wound healing was impaired in all treated rats by the administration of cyclophosphamide on days 1, 3, and 5. Wound tensile breaking strength was determined on days 4, 7, and 14. RESULTS:: Sustained release of either TGF-ss or PDGF alone not only failed to improve the healing of cyclophosphamide-induced impaired wound healing but resulted in a paradoxical decrease in wound tensile breaking strength by day 7. However, the combined delivery of both TGF-ss and PDGF improved wound healing and significantly increased wound tensile breaking strength by day 7. CONCLUSIONS:: Sustained-release delivery of TGF-ss and PDGF in combination, but not separately, by a subcutaneously implanted drug delivery system significantly improves cyclophosphamide-induced impaired wound healing in rats. PMID: 19935295 [PubMed - as supplied by publisher] |
| Long-Term Persistence of Tissue-Engineered Adipose Flaps in a Murine Model to 1 Year: An Update.
November 26, 2009 at 10:12 am
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| | Long-Term Persistence of Tissue-Engineered Adipose Flaps in a Murine Model to 1 Year: An Update. Plast Reconstr Surg. 2009 Oct;124(4):1077-1084 Authors: Findlay MW, Messina A, Thompson EW, Morrison WA BACKGROUND:: Tissue engineering of patient-specific adipose tissue has the potential to revolutionize reconstructive surgery. Numerous models have been described for the production of adipose tissue with success in the short term, but little has been reported on the stability of this tissue-engineered fat beyond 4 months. METHODS:: A murine model of de novo adipogenesis producing a potentially transplantable adipose tissue flap within 4 to 6 weeks was developed in the authors' laboratory. In this study, the authors assess the ability of three-chamber (44-mul volume) configurations shown to be adipogenic in previous short-term studies (autograft, n = 8; open, n = 6; fat flap, n = 11) to maintain their tissue volume for up to 12 months in vivo, to determine the most adipogenic configuration in the long term. RESULTS:: Those chambers having the most contact with existing vascularized adipose tissue (open and fat flap groups) showed increased mean adipose tissue percentage (77 +/- 5.6 percent and 81 +/- 6.9 percent, respectively; p < 0.0007) and volume (12 +/- 6.8 mul and 30 +/- 14 mul, respectively; p < 0.025) when compared with short-term controls and greater adipose tissue volume than the autograft (sealed) chamber group (4.9 +/- 5.8 mul; p = 0.0001) at 1 year. Inclusion of a vascularized fat flap within the chamber produced the best results, with new fat completely filling the chamber by 1 year. CONCLUSIONS:: These findings demonstrate that fat produced by tissue engineering is capable of maintaining its volume when the appropriate microenvironment is provided. This has important implications for the application of tissue-engineering techniques in humans. PMID: 19935290 [PubMed - as supplied by publisher] |
| In vitro osteogenic differentiation of adipose stem cells after lentiviral transduction with green fluorescent protein.
November 26, 2009 at 10:12 am
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| | In vitro osteogenic differentiation of adipose stem cells after lentiviral transduction with green fluorescent protein. J Craniofac Surg. 2009 Nov;20(6):2193-9 Authors: Wang Q, Steigelman MB, Walker JA, Chen S, Hornsby PJ, Bohnenblust ME, Wang HT BACKGROUND:: Adipose-derived stem cells (ASCs) have the potential to differentiate into osteogenic cells that can be seeded into scaffolds for tissue engineering for use in craniofacial bone defects. Green fluorescent protein (GFP) has been widely used as a lineage marker for mammalian cells. The use of fluorescent proteins enables cells to be tracked during manipulation such as osteogenic differentiation within three-dimensional scaffolds. The purpose of this study was to examine whether ASCs introduced with GFP-encoding lentivirus vector exhibit adequate GFP fluorescence and whether the expression of GFP interfered with osteogenic differentiation of ASCs in both monolayer and three-dimensional scaffolds in vitro. METHODS:: Primary ASCs were harvested from the inguinal fat pad of Sprague Dawley rats. Isolated ASCs were cultured and infected with a lentiviral vector encoding GFP and plated into both monolayers and three-dimensional scaffolds in vitro. The cells were then placed in osteogenic medium. Osteogenic differentiation of the GFP-ASCs was assessed using alizarin red S, alkaline phosphate staining, and immunohistochemistry staining of osteocalcin with quantification of alizarin red S and osteocalcin staining. RESULTS:: The efficacy of infection of ASCs with a lentiviral vector encoding GFP was high. Cell-cultured GFP-ASCs remained fluorescent over the 8 weeks of the study period. The GFP-ASCs were successfully induced into osteogenic cells both in monolayers and three-dimensional scaffolds. Whereas the quanitification of alizarin red S revealed no difference between osteoinduced ASCs with or without GFP, the quantification of osteocalcin revealed increased staining in the GFP group. CONCLUSIONS:: Transduction of isolated ASCs using a lentiviral vector encoding GFP is an effective method for tracing osteoinduced ASCs in vitro. Quantification data showed no decrease in staining of the osteoinduced ASCs. PMID: 19934675 [PubMed - in process] |
| Genetic Factors on Mouse Chromosome 18 Affecting Susceptibility to Testicular Germ Cell Tumors and Permissiveness to Embryonic Stem Cell Derivation.
November 26, 2009 at 10:12 am
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| | Genetic Factors on Mouse Chromosome 18 Affecting Susceptibility to Testicular Germ Cell Tumors and Permissiveness to Embryonic Stem Cell Derivation. Cancer Res. 2009 Nov 24; Authors: Anderson PD, Nelson VR, Tesar PJ, Nadeau JH Despite strong heritability, little is known about the genetic control of susceptibility to testicular germ cell tumors (TGCT) in humans or mice. Although the mouse model of spontaneous TGCTs has been extensively studied, conventional linkage analysis has failed to locate the factors that control teratocarcinogenesis in the susceptible 129 family of inbred strains. As an alternative approach, we used both chromosome substitution strains (CSS) to identify individual chromosomes that harbor susceptibility genes and a panel of congenic strains derived from a selected CSS to determine the number and location of susceptibility variants on the substituted chromosome. We showed that 129-Chr 18(MOLF) males are resistant to spontaneous TGCTs and that at least four genetic variants control susceptibility in males with this substituted chromosome. In addition, early embryonic cells from this strain fail to establish embryonic stem cell lines as efficiently as those from the parental 129/Sv strain. For the first time, 129-derived genetic variants that control TGCT susceptibility and fundamental aspects of embryonic stem cell biology have been localized in a genetic context in which the genes can be identified and functionally characterized. [Cancer Res 2009;69(23):9112-7]. PMID: 19934337 [PubMed - as supplied by publisher] |
| The Modulation of MicroRNAs by Type I IFN through the Activation of Signal Transducers and Activators of Transcription 3 in Human Glioma.
November 26, 2009 at 10:12 am
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| | The Modulation of MicroRNAs by Type I IFN through the Activation of Signal Transducers and Activators of Transcription 3 in Human Glioma. Mol Cancer Res. 2009 Nov 24; Authors: Ohno M, Natsume A, Kondo Y, Iwamizu H, Motomura K, Toda H, Ito M, Kato T, Wakabayashi T Type I IFNs are involved in double-stranded RNA responses. Here, we investigated the possibility that IFN-beta may induce or downregulate cellular microRNAs (miRNA) in human neoplasms and thereby use the RNA interference system to show antitumor effects. Because of its known connection to glioma biology, we focused on miR-21 among seven miRNAs influenced by IFN-beta. We analyzed the effect of IFN-beta treatment on miR-21 expression in glioma cells and intracranial glioma xenografts. IFN-beta treatment reduced miR-21 expression in glioma cells markedly, and IFN-beta administration suppressed the growth of glioma-initiating cell-derived intracranial tumors. The levels of primary miR-21 gene transcripts, precursor miR-21, and mature miR-21 decreased 6 hours after the addition of IFN-beta, indicating that the reduction in miR-21 levels was due to transcriptional suppression. We did reporter assays to elucidate the IFN-beta-mediated suppression of miR-21; the addition of signal transducers and activators of transcription 3 (STAT3)-expressing vectors induced the IFN-beta-mediated suppression of miR-21, whereas STAT3-inhibiting agents inhibited the miR-21 suppression. Thus, the results of our study show that the downregulation of miR-21 contributes to the antitumor effects of IFN-beta and that miR-21 expression is negatively regulated by STAT3 activation. These results highlight the importance of understanding the transcriptional regulation of the miRNAs involved in oncogenesis. (Mol Cancer Res 2009;7(12):OF1-9). PMID: 19934272 [PubMed - as supplied by publisher] |
| In Vivo Assessment of the Antimicrobial Activity of a Calcium-Deficient Apatite Vancomycin Drug Delivery System in a MRSA Rabbit Osteomyelitis Experimental Model.
November 26, 2009 at 10:12 am
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| | In Vivo Assessment of the Antimicrobial Activity of a Calcium-Deficient Apatite Vancomycin Drug Delivery System in a MRSA Rabbit Osteomyelitis Experimental Model. Antimicrob Agents Chemother. 2009 Nov 23; Authors: Amador G, Gautier H, LE Mabecque V, Miegeville AF, Potel G, Bouler JM, Weiss P, Caillon J, Jacqueline C Antimicrobial activity of calcium-deficient apatite loaded with different concentrations (25, 100 and 500 mug/mg) of vancomycin was evaluated as a filling biomaterial in a MRSA rabbit acute osteomyelitis model. Bacterial counts in bone, bone marrow, and joint fluid treated with forms of the apatite were compared to tissue receiving a constant intra-venous vancomycin infusion after 4 days. This study demonstrates that calcium-deficient apatite loaded with vancomycin dramatically decreases the bacterial counts in bone and marrow. PMID: 19933800 [PubMed - as supplied by publisher] |
| mimiRNA: a microRNA expression profiler and classification resource designed to identify functional correlations between microRNAs and their targets.
November 26, 2009 at 10:12 am
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| | mimiRNA: a microRNA expression profiler and classification resource designed to identify functional correlations between microRNAs and their targets. Bioinformatics. 2009 Nov 17; Authors: Ritchie W, Flamant S, Rasko JE MOTIVATION: microRNAs (miRNAs) are short non-coding RNAs that regulate gene expression by inhibiting target mRNA genes. Their tissue-specific and disease-specific expression patterns have immense therapeutic and diagnostic potential. To understand these patterns, a reliable compilation of miRNA and mRNA expression data is required to compare multiple tissue types. Moreover, with the appropriate statistical tools, such a resource could be interrogated to discover functionally related miRNA-mRNA pairs. RESULTS: We have developed mimiRNA, an on-line resource that integrates expression data from 1483 samples and permits visualization of the expression of 635 human miRNAs across 188 different tissues or cell types. mimiRNA incorporates a novel sample classification algorithm, ExParser, that groups identical miRNA or mRNA experiments from separate sources. This enables mimiRNA to provide reliable expression profiles and to discover functional relations between miRNAs and mRNAs such as miRNA targets. Additionally, mimiRNA incorporates a decision tree algorithm to discover distinguishing miRNA features between two tissue or cell types. We validate the efficacy of our resource on independent experimental data and through biologically relevant analyses. AVAILABILITY: http://mimirna.centenary.org.au CONTACT: j.rasko@centenary.org.au SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online. PMID: 19933167 [PubMed - as supplied by publisher] |
| Bone Marrow Mesenchymal Stem Cells Reduce Intestinal Ischemia/Reperfusion Injuries in Rats.
November 26, 2009 at 10:12 am
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| | Bone Marrow Mesenchymal Stem Cells Reduce Intestinal Ischemia/Reperfusion Injuries in Rats. J Surg Res. 2009 Aug 22; Authors: Jiang H, Qu L, Li Y, Gu L, Shi Y, Zhang J, Zhu W, Li J BACKGROUND: Adult stem cells are promising novel therapies in regenerative medicine. We investigated effects of bone marrow-derived mesenchymal stem cells (MSCs) on intestinal mucosal permeability impaired by ischemia/reperfusion (I/R). METHODS: We used a common I/R model in rats to induce intestinal injury by clamping and unclamping the superior mesenteric artery (SMA) in female Sprague-Dawley rats. MSCs were directly injected into the small intestinal submucosa of the syngenic female rats. Control group were injected with the same volume of 0.9% sodium chloride. Small intestine samples were examined for the engraftment of donor-derived mesenchymal stem cells (MSCs) by Y chromosome in situ hybridization analysis. The small intestinal permeability and histomorphologic alternations were measured to evaluate the therapeutic effect of MSCs transplantation. RESULTS: Small intestinal permeability and villi injuries were significantly reduced in the MSCs administrated group compared with control group. MSCs administration accelerated the recovery of the intestinal barrier dysfunction. CONCLUSION: We concluded that submucosal infusion of MSCs might exert protective effects on the integrity of intestinal barrier. PMID: 19932900 [PubMed - as supplied by publisher] |
| The use of immobilized osteogenic growth peptide on gradient substrates synthesized via click chemistry to enhance MC3T3-E1 osteoblast proliferation.
November 26, 2009 at 10:12 am
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| | The use of immobilized osteogenic growth peptide on gradient substrates synthesized via click chemistry to enhance MC3T3-E1 osteoblast proliferation. Biomaterials. 2009 Nov 20; Authors: Moore NM, Lin NJ, Gallant ND, Becker ML In this study, we report the use of surface immobilized peptide concentration gradient technology to characterize MC3T3-E1 osteoblast cell response to osteogenic growth peptide (OGP), a small peptide found naturally in human serum at mumol/L concentrations. OGP was coupled to oxidized self assembled monolayer (SAM) gradients by a polyethylene oxide (PEO) linker using click chemistry. After 4h incubation with MC3T3-E1 cells, OGP functionalized surfaces had higher cell attachment at low peptide concentrations compared to control gradients. By day 3, OGP gradient substrates had higher cell densities compared to control gradients at all concentrations. MC3T3-E1 cell doubling time was 35% faster on OGP substrates relative to SAM gradients alone, signifying an appreciable increase in cell proliferation. This increase in cell proliferation, or decrease in doubling time, due to OGP peptide was reduced by day 7. Hence, immobilized OGP increased cell proliferation from 0 days to 3 days at all densities indicating it may be useful as a proliferative peptide that can be used in tissue engineering substrates. PMID: 19932505 [PubMed - as supplied by publisher] |
| Polyester based nerve guidance conduit design.
November 26, 2009 at 10:12 am
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| | Polyester based nerve guidance conduit design. Biomaterials. 2009 Nov 20; Authors: Yucel D, Kose GT, Hasirci V Nerve conduits containing highly aligned architecture that mimics native tissues are essential for efficient regeneration of nerve injuries. In this study, a biodegradable nerve conduit was constructed by converting a porous micropatterned film (PHBV-P(L-D,L)LA-PLGA) into a tube wrapping aligned electrospun fibers (PHBV-PLGA). The polymers were chosen so that the protective tube would erode slower than the fibrous core to achieve complete healing before the tube eroded. The pattern dimensions and the porosity (58.95 (%) with a maximum pore size of 4-5mum) demonstrated that the micropatterned film would enable the migration, alignment and survival of native cells for proper regeneration. This film had sufficiently high mechanical properties (ultimate tensile strength: 3.13MPa, Young's Modulus: 0.08MPa) to serve as a nerve guide. Electrospun fibers, the inner part of the tubular construct, were well aligned with a fiber diameter of ca. 1.5mum. Fiber properties were especially influenced by polymer concentration. SEM showed that the fibers were aligned parallel to the groove axis of the micropatterned film within the tube as planned considering the nerve tissue architecture. This two component nerve conduit appears to have the right organization for testing in vitro and in vivo nerve tissue engineering studies. PMID: 19932504 [PubMed - as supplied by publisher] |
| [Replacement of the trachea using surgical reconstruction: Current state of research.]
November 26, 2009 at 10:12 am
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| | [Replacement of the trachea using surgical reconstruction: Current state of research.] Ann Otolaryngol Chir Cervicofac. 2009 Nov 20; Authors: Schultz P, Vautier D, Dupret-Bories A, Debry C, Charpiot A OBJECTIVE: To review the main studies and the recent surgical procedures in tracheal reconstruction. MATERIAL AND METHOD: The literature search was conducted using the key words "tracheal reconstruction", "grafts", and "tissue engineering" and by selecting references from the articles reviewed as well as the experience of the authors in this field. RESULTS: Surgical reconstruction for tracheal replacement without using biomaterials involves tissue grafts (auto- or allografts) and tissue engineering. Among the many procedures already described, three new techniques have emerged these past few years employing autologous mesenchymal stem-cell-derived chondrocytes, autologous cultured epithelial cells, and a matrix derived from tracheal graft; costal cartilage, recipient mucosa, and local or free flaps, and an aortic graft. These procedures have been proposed in humans with apparently good results but with a still limited follow-up. CONCLUSIONS: Tracheal reconstruction techniques have recently progressed and replacing a long segment of trachea can be envisaged for the future. Moreover, these reconstructions, in conjunction with biomaterial development, would facilitate the design and the implantation of a laryngeal prosthesis. PMID: 19932466 [PubMed - as supplied by publisher] |
| Human embryonic stem-cell derivatives for full reconstruction of the pluristratified epidermis: a preclinical study.
November 26, 2009 at 10:12 am
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| | Human embryonic stem-cell derivatives for full reconstruction of the pluristratified epidermis: a preclinical study. Lancet. 2009 Nov 21;374(9703):1745-1753 Authors: Guenou H, Nissan X, Larcher F, Feteira J, Lemaitre G, Saidani M, Del Rio M, Barrault CC, Bernard FX, Peschanski M, Baldeschi C, Waksman G BACKGROUND: Cell therapy for large burns is dependent upon autologous epidermis reconstructed in vitro. However, the effectiveness of current procedures is limited by the delay needed to culture the patient's own keratinocytes. To assess whether the keratinocyte progeny of human embryonic stem cells (hESCs) could be used to form a temporary skin substitute for use in patients awaiting autologous grafts, we investigated the cells' capability of constructing a pluristratified epidermis. METHODS: hESCs from lines H9 and SA01 were seeded at least in triplicate on fibroblast feeder cells for 40 days in a medium supplemented with bone morphogenetic protein 4 and ascorbic acid. Molecular characterisation of cell differentiation was done throughout the process by quantitative PCR, fluorescence-activated cell sorting, and immunocytochemical techniques. Keratinocyte molecular differentiation and functional capacity to construct a human epidermis were assessed in vitro and in vivo. FINDINGS: From hESCs, we generated a homogeneous population of cells that showed phenotypic characteristics of basal keratinocytes. Expression levels of genes encoding keratin 14, keratin 5, integrin alpha6, integrin beta4, collagen VII, and laminin 5 in these cells were similar to those in basal keratinocytes. After seeding on an artificial matrix, keratinocytes derived from hESCs (K-hESCs) formed a pluristratified epidermis. Keratin-14 immunostaining was seen in the basal compartment, with keratin 10 present in layers overlying the basal layer. Involucrin and filaggrin, late markers of epidermal differentiation, were detected in the uppermost layers only. 12 weeks after grafting onto five immunodeficient mice, epidermis derived from K-hESCs had a structure consistent with that of mature human skin. Human involucrin was appropriately located in spinous and granular layers and few Ki67-positive cells were detected in the basal layer. INTERPRETATION: hESCs can be differentiated into basal keratinocytes that are fully functional-ie, able to construct a pluristratified epidermis. This resource could be developed to provide temporary skin substitutes for patients awaiting autologous grafts. FUNDING: Institut National de la Santé et de la Recherche Médicale, University Evry Val d'Essonne, Association Française contre les Myopathies, Fondation René Touraine, and Genopole. PMID: 19932355 [PubMed - as supplied by publisher] |
| Use of the Induced Membrane Technique for Bone Tissue Engineering Purposes: Animal Studies.
November 26, 2009 at 10:12 am
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| | Use of the Induced Membrane Technique for Bone Tissue Engineering Purposes: Animal Studies. Orthop Clin North Am. 2010 Jan;41(1):49-56 Authors: Viateau V, Bensidhoum M, Guillemin G, Petite H, Hannouche D, Anagnostou F, Pélissier P Animal experiments using the induced membrane procedure for bone tissue engineering purposes have provided evidence that the membrane has structural characteristics and biologic properties that may be used for bone tissue engineering purposes. Clinically relevant animal models have demonstrated that standardized particulate bone constructs can be used to repair large bone defects using the procedure and that the osteogenic ability of these constructs partially approaches that of bone autografts. PMID: 19931052 [PubMed - as supplied by publisher] |
| Engineering Considerations for Process Development in Mammalian Cell Cultivation.
November 26, 2009 at 10:12 am
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| | Engineering Considerations for Process Development in Mammalian Cell Cultivation. Curr Pharm Biotechnol. 2009 Nov 23; Authors: Zhang H, Wang W, Quan C, Fan S Mammalian cell cultivation plays a great role in producing protein therapeutics in the last decades. Many engineering parameters are considered for optimization during process development in mammalian cell cultivation, only shear and mixing are especially highlighted in this paper. It is believed that shear stress due to agitation has been over-estimated to damage cells, but shear may result in nonlethal physiological responses. There is no cell damage in the regions where bubbles form, break up and coalescence, but shear stress becomes significant in the wake of rising bubbles and causes great damage to cells in bubble burst regions. Mixing is not sufficient to provide homogeneous dissolved oxygen tension, pH, CO(2) and nutrients in large-scale bioreactors, which can bring severe problems for cell growth, product formation and process control. Scale-down reactors have been developed to address mixing and shear problems for parallel operations. Engineering characterization in conventional and recently developed scale-down bioreactors has been briefly introduced. Process challenges for cultivation of industrial cell lines in high cell densities as well as cultivation of stem cells and other human cells for regenerative medicine, tissue engineering and gene therapy are prospected. Important techniques, such as micromanipulation and nanomanipulation (optical tweezers) for single cell analysis, computational fluid dynamics (CFD) for shear and mixing characterization, and miniaturized bioreactors, are being developed to address those challenges. PMID: 19929819 [PubMed - as supplied by publisher] |
| The Potential of Embryonic Stem Cells Combined with -Omics Technologies as Model Systems for Toxicology.
November 26, 2009 at 10:12 am
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| | The Potential of Embryonic Stem Cells Combined with -Omics Technologies as Model Systems for Toxicology. Curr Med Chem. 2009 Nov 17; Authors: Winkler J, Sotiriadou I, Chen S, Hescheler J, Sachinidis A The derivation of pluripotent embryonic stem (ES) cell lines has opened up new areas of research in basic and applied science, most significantly in developmental biology and regenerative medicine. While application-oriented research has for the most part focussed on obtaining differentiated, organotypic cells from ES cells for future cell grafting therapies, ES cells have more immediate potential for use in toxicological in vitro assays used during drug development. ES cells are derived from blastocyst-stage embryos and offer an in vitro model for early development, thus enabling tests for teratogenicity testing in a human cell culture system and avoiding the pitfalls of inter-species differences. Differentiated, organotypic cells obtained from ES cells can potentially replace the primary cells and cell lines currently used for in vitro toxicology by offering a more consistent and potentially limitless source of differentiated cells. This can facilitate the establishment of comprehensive toxicogenomics and -proteomics databases and complement current databases that rely on data obtained from animal experiments. More recently, induced pluripotent stem (iPS) cells with ES cell-like properties have been obtained through reprogramming of somatic cells, thus enabling the generation of disease-specific cell lines. We review the potential of combining ES cells and ES cell-derived somatic cells with "omics" technologies for in vitro toxicology with a particular emphasis on the development of toxicogenomics and toxicoproteomics signatures. A separate section describes the potential of iPS cells for toxicology. PMID: 19929785 [PubMed - as supplied by publisher] |
| Human adipose-derived mesenchymal stem cells in vitro: evaluation of an optimal expansion medium preserving stemness.
November 26, 2009 at 10:12 am
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| | Human adipose-derived mesenchymal stem cells in vitro: evaluation of an optimal expansion medium preserving stemness. Cytotherapy. 2009 Nov 24; Authors: Baer PC, Griesche N, Luttmann W, Schubert R, Luttmann A, Geiger H Background aims. The potential of cultured adipose-derived stem cells (ASC) in regenerative medicine and new cell therapeutic concepts has been shown recently by many investigations. However, while the method of isolation of ASC from liposuction aspirates depending on plastic adhesion is well established, a standard expansion medium optimally maintaining the undifferentiated state has not been described. Methods. We cultured ASC in five commonly used culture media (two laboratory-made media and three commercially available media) and compared them with a standard medium. We analyzed the effects on cell morphology, proliferation, hepatocyte growth factor (HGF) expression, stem cell marker profile and differentiation potential. Proliferation was measured with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and a fluorescent assay. Release of HGF was assessed by an immunoassay. Expression of characteristic stem cell-related transcription factors and markers was evaluated by quantitative polymerase chain reaction (qPCR) (Nanog, Sox-2, Rex-1, nestin and Oct-4) and flow cytometry (CD44, CD73, CD90, CD105 and CD166), and differentiation was shown by adipogenic medium. Results. The morphology and expansion of ASC were significantly affected by the media used, whereas none of the media influenced the ASC potential to differentiate into adipocytes. Furthermore, two of the media induced an increase in expression of transcription factors, an increased secretion of HGF and a decrease in CD105 expression. Conclusions. Culture of ASC in one of these two media before using the cells in cell therapeutic approaches may have a benefit on their regenerative potential. PMID: 19929458 [PubMed - as supplied by publisher] |
| Altered Calcium Dynamics Mediates P19-Derived Neuron-Like Cell Responses to Millimeter-Wave Radiation.
November 26, 2009 at 10:12 am
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| | Altered Calcium Dynamics Mediates P19-Derived Neuron-Like Cell Responses to Millimeter-Wave Radiation. Radiat Res. 2009 Dec;172(6):725-736 Authors: Titushkin IA, Rao VS, Pickard WF, Moros EG, Shafirstein G, Cho MR Abstract Titushkin, I. A., Rao, V. S., Pickard, W. F., Moros, E. G., Shafirstein, G. and Cho, M. R. Altered Calcium Dynamics Mediates P19-Derived Neuron-Like Cell Responses to Millimeter-Wave Radiation. Intracellular calcium oscillations have long been recognized as a principal mediator of many vital cellular activities. Furthermore, Ca(2+) dynamics can be modulated by external physical cues, including electromagnetic fields. While cellular responses to low-frequency electric fields have been established, the possible non-thermal effects of millimeter-wave (MMW) radiation are still a subject of discussion and debate. We used mouse embryonic stem cell-derived neuronal cells and a custom-built 94 GHz applicator to examine in real time the altered Ca(2+) oscillations associated with MMW stimulation. MMW irradiation at 18.6 kW/m(2) nominal power density significantly increased the Ca(2+) spiking frequency in the cells exhibiting Ca(2+) activity. The N-type calcium channels, phospholipase C enzyme, and actin cytoskeleton appear to be involved in mediating increased Ca(2+) spiking. Reorganization of the actin microfilaments by a 94 GHz field seems to play a crucial role in modulating not only Ca(2+) activity but also cell biomechanics. Many but not all observed cellular responses to MMW were similar to thermally induced effects. For example, cell exposure to a 94 GHz field induced nitric oxide production in some morphologically distinct neuronal cells that could not be reproduced by thermal heating of the cells up to 42 degrees C. The highest observed average temperature rise in the MMW exposure chamber was approximately 8 degrees C above the room temperature, with possible complex non-uniform microscopic distribution of heating rates at the cell level. Our findings may be useful to establish quantitative molecular benchmarks for elucidation of nociception mechanisms and evaluation of potential adverse bioeffects associated with MMW exposure. Moreover, control of Ca(2+) dynamics by MMW stimulation may offer new tools for regulation of Ca(2+)-dependent cellular and molecular activities, for example, in tissue engineering applications. PMID: 19929419 [PubMed - as supplied by publisher] |
| Anti-L-NGFR and -CD34 Monoclonal Antibodies identify multipotent mesenchymal stem cells in human adipose tissue.
November 26, 2009 at 10:12 am
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| | Anti-L-NGFR and -CD34 Monoclonal Antibodies identify multipotent mesenchymal stem cells in human adipose tissue. Stem Cells Dev. 2009 Nov 23; Authors: Quirici N, Scavullo C, de Girolamo L, Lopa S, Arrigoni E, Lambertenghi Deliliers G, Brini AT Stem cells hold great promise in tissue engineering for repairing tissues damaged by disease or injury. Mesenchymal stem cells (MSCs) are multipotent cells able to proliferate and differentiate into multiple mesodermal tissues such as bone, cartilage, muscle, tendon and fat. We have previously reported that the low-affinity nerve growth factor receptor (L-NGFR or CD271) defines a subset of cells with high proliferative, clonogenic and multipotential differentiation ability in adult bone marrow (BM). It has been recently shown that adipose tissue is an alternative source of adult multipotent stem cells and human adipose-derived stem cells, selected by plastic-adherence (PA hASCs), have been extensively characterized for their functional potentials in vitro. In this study, immuno-selected L-NGFR+ and CD34+ subpopulations have been analyzed and compared with the PA hASCs. Phenotypic profile of freshly purified subpopulations showed an enrichment in the expression of some stem cell markers: indeed, a great percentage of L-NGFR+ cells co-expressed CD34 and CD117 antigens, whereas the endothelial-committed progenitor markers KDR and P1H12 were mainly expressed on CD34+ cells. Differently from PA hASCs, the immuno-separated fractions showed high increments in cell proliferation, and the fibroblast colony-forming activity (CFU-F) was maintained throughout the time of culture. Furthermore, the immuno-selected populations showed a greater differentiative potential towards adipocytes, osteoblasts and chondrocyte-like cells, compared to PA hASCs. Our data suggest that both CD34+ and L-NGFR+ hASCs can be considered alternative candidates for tissue engineering and regenerative medicine applications. PMID: 19929314 [PubMed - as supplied by publisher] |
| Electrospun polymer nanofibrous membrane for filtration.
November 26, 2009 at 10:12 am
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| | Electrospun polymer nanofibrous membrane for filtration. J Nanosci Nanotechnol. 2009 Sep;9(9):5402-5 Authors: Rajesh KP, Natarajan TS Modern processing techniques in fiber technology combined with novel polymer materials results in new products. Electrospinning is one of the methods to prepare nanofibers of polymer or polymer composite materials. Membranes made out of these nanofibers can be used in variety of applications like filtration, tissue engineering, drug delivery etc. The membrane properties are governed by their surface properties and pore distribution, as well as their morphology. In this paper we are reporting the preparation and characterization of sulfonated poly(ether ether ketone) nanofibers and membrane made out of these fibers. The surface and cross sectional morphologies are characterized using scanning electron microscopy. Further the membrane is characterized for pore size distribution and pure water permeability. This work can be extended for exploring the use of electrospinning nanofibrous membranes for filter application. PMID: 19928232 [PubMed - in process] | | | 
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