|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Flexible scaffolds based on poly(trimethylene carbonate) networks for cardiac tissue engineering. J Control Release. 2010 Nov 20;148(1):e74-6 Authors: Bat E, Harmsen MC, Plantinga JA, van Luyn MJ, Feijen J, Grijpma DW PMID: 21529639 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Electroconductive polymeric nanowire templates facilitates in vitro C17.2 neural stem cell line adhesion, proliferation and differentiation. Acta Biomater. 2011 Apr 20; Authors: Bechara S, Wadman L, Popat KC Stem cells still remain one of the most exciting and lucrative options for treatment of a variety of nervous system disorders and diseases. Although there are neural stem cells present in adults, the ability of both the peripheral and central nervous system for self-repair is limited at best. As such, there is a great need for a tissue engineering approach to solve nervous system disorders and diseases. In this study, we have developed electrically conductive surfaces with controlled arrays of high aspect ratio nanowires for the growth and maintenance of neural stem cells. The nanowire surfaces were fabricated from polycaprolactone using a novel nanotemplating technique, and were coated with an electrically conductive polymer, polypyrrole. The polypyrrole-coated nanowire surfaces were characterized using scanning electron microscopy and X-ray photoelectron spectroscopy. Additionally, the surface resistance of polypyrrole-coated nanowire surfaces was measured. C17.2 neural stem cells were used to evaluate the efficacy of the polypyrrole-coated nanowire surfaces to promote cell adhesion, proliferation and differentiation. The results presented here indicate significantly higher cellular adhesion and proliferation on polypyrrole-coated nanowire surfaces as compared to control surfaces. The differentiation potential of polypyrrole nanowire surfaces was also evaluated by immunostaining key neuronal markers that are expressed when NSCs differentiate into their respective neural lineages. PMID: 21530693 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Proliferation of human keratinocytes and cocultured human keratinocytes and fibroblasts in three-dimensional fibrin constructs. Tissue Eng Part A. 2011 Feb;17(3-4):429-37 Authors: Sese N, Cole M, Tawil B Over the last several years, our in vitro and in vivo studies have focused on optimizing the use of fibrin to deliver cells. We have shown that some three-dimensional (3D) fibrin constructs with specific fibrinogen and thrombin concentration support robust proliferation of normal human dermal fibroblasts, whereas different fibrinogen and thrombin concentrations support high mesenchymal stem cell proliferation in 3D fibrin constructs. In this article, we found that normal human epithelial keratinocytes proliferate well in 3D fibrin constructs consist of fibrinogen concentration ranging from 17 to 33 mg/mL and thrombin concentration of 1 U/mL. Further, using a new proliferation assay, we studied the proliferation of fibroblasts and keratinocytes cocultured in various 3D fibrin constructs of different fibrinogen and thrombin concentrations. We found that 3D fibrin constructs with a range of fibrinogen concentration (5-34 mg/mL) and a thrombin concentration of 1 U/mL produce an optimal cell proliferation for both cell types when cocultured. This profile of proliferation is different from that seen when keratinocytes or fibroblasts are incorporated separately in 3D fibrin constructs. In conclusion, we found that one needs to choose the fibrinogen and thrombin concentration carefully depending on the cell type to deliver; that is, different fibrin constructs with different fibrinogen and thrombin concentration are required to deliver fibroblasts or keratinocytes alone or to codeliver both cell types. Moreover, there seems to be a cross-talk between keratinocytes and fibroblasts when they are cointroduced in 3D fibrin constructs. This feedback could be due to the effects of growth factors produced by the two cell types in the 3D fibrin constructs. PMID: 20807013 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Engineering towards functional tissues and organs. Organogenesis. 2010 Jul-Sep;6(3):139-40 Authors: Jayasinghe SN PMID: 21197214 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue-engineered vascular graft remodeling in a growing lamb model: expression of matrix metalloproteinases. Eur J Cardiothorac Surg. 2011 Apr 27; Authors: Cummings I, George S, Kelm J, Schmidt D, Emmert MY, Weber B, Zünd G, Hoerstrup SP Objectives: We have previously demonstrated the functionality and growth of autologous, living, tissue-engineered vascular grafts (TEVGs) in long-term animal studies. These grafts showed substantial in vivo tissue remodeling and approximation to native arterial wall characteristics. Based on this, in vitro and in vivo matrix metalloproteinase (MMP) activity of TEVGs is investigated as a key marker of matrix remodeling. Methods: TEVGs fabricated from biodegradable scaffolds (polyglycolic-acid/poly-4-hydroxybutyrate, PGA/P4HB) seeded with autologous vascular cells were cultured in static and dynamic in vitro conditions. Thereafter, TEVGs were implanted as pulmonary artery replacements in lambs and followed up for 2 years. Gelatin gel zymography to detect MMP-2 and -9 was performed and collagen content quantified (n=5). Latent (pro) and active MMP-2 and -9 were detected. Results: Comparable levels of active MMP-9 and pro-MMP-2 were detected in static and dynamic culture. Higher levels of active MMP-2 were detected in dynamic cultures. Expression of MMP-2 and -9 was minimal in native grafts but was increased in implanted TEVG. Pro-MMP-9 was expressed 20 weeks post implantation and persisted up to 80 weeks post implantation. Collagen content in vitro was increased in dynamically conditioned TEVG as compared with static constructs and was increased in vivo compared with the corresponding native pulmonary artery. Conclusions: MMPs are up-regulated in vitro by dynamic culture conditions and could contribute to increased matrix remodeling, native analogous tissue formation and functional growth of TEVGs in vivo. Monitoring of MMP activity, for example, by molecular imaging techniques, may enable the non-invasive assessment of functional tissue quality in future clinical tissue-engineering applications. PMID: 21530291 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Amphibians as research models for regenerative medicine. Organogenesis. 2010 Jul-Sep;6(3):141-50 Authors: Song F, Li B, Stocum DL The ability to regenerate bone across a critical size defect would be a marked clinical advance over current methods for dealing with such structural gaps. Here, we briefly review the development of limb bones and the mandible, the regeneration of urodele limbs after amputation, and present evidence that urodele and anuran amphibians represent a valuable research model for the study of segment defect regeneration in both limb bones and mandible. PMID: 21197215 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Recent progress in cartilage tissue engineering. Curr Opin Biotechnol. 2011 Apr 28; Authors: Keeney M, Lai JH, Yang F Despite over two decades of research on cartilage tissue engineering, very few products have moved from bench to bedside and effective therapy remains lacking. This review discusses recent progress in developing novel strategies for engineering cartilage tissues with long-term functionality. Specifically we focus on the following aspects including identifying promising cell sources, designing 3D scaffolds with dynamic and spatially patterned cues to guide desired cellular processes, mimicking zonal organization, integrating with host tissue, and monitoring cell fate and tissue regeneration in situ. PMID: 21531126 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Graphene for Controlled and Accelerated Osteogenic Differentiation of Human Mesenchymal Stem Cells. ACS Nano. 2011 Apr 29; Authors: Nayak TR, Andersen H, Makam VS, Khaw C, Bae S, Xu X, Ee PL, Ahn JH, Hong BH, Pastorin G, Ozyilmaz B Modern tissue engineering strategies combine living cells and scaffold materials to develop biological substitutes that can restore tissue functions. Both natural and synthetic materials have been fabricated for transplantation of stem cells and their specific differentiation into muscles, bones and cartilages. One of the key objectives for bone regeneration therapy to be successful is to direct stem cells' proliferation and to accelerate their differentiation in a controlled manner through the use of growth factors and osteogenic inducers. Here we show that graphene provides a promising biocompatible scaffold that does not hamper the proliferation of human mesenchymal stem cells (hMSCs) and accelerates their specific differentiation into bone cells. The differentiation rate is comparable to the one achieved with common growth factors, demonstrating graphene's great potential for stem cell research. PMID: 21528849 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microstructure design of biodegradable scaffold and its effect on tissue regeneration. Biomaterials. 2011 Apr 27; Authors: Chen Y, Zhou S, Li Q Biodegradable scaffolds play a critical role in therapeutic tissue engineering, in which the matrix degradation and tissue ingrowth are of particular importance for determining the ongoing performance of tissue-scaffold system during regenerative process. This paper aims to explore the mechanobiological process within biodegradable scaffolds, where the representative volume element (RVE) is extracted from periodic scaffold micro-architectures as a base-cell design model. The degradation of scaffold matrix is modeled in terms of a stochastic hydrolysis process enhanced by diffusion-controlled autocatalysis; and the tissue ingrowth is modeled through the mechano-regulatory theory. By using the finite element based homogenization technique and topology optimization approach, the effective properties of various periodic scaffold structures are obtained. To explore the effect of scaffold design on the mechanobiological evolutions of tissue-scaffold systems, different scaffold architectures are considered for polymer degradation and tissue regeneration. It is found that the different tissues can grow into the degraded voids inside the polymer matrix. It is demonstrated that the design of scaffold architecture has a considerable impact on the tissue regeneration outcome, which exhibits the importance of implementing different criteria in scaffold micro-structural design, before being fabricated via rapid prototyping technique, e.g. solid free-form fabrication (SFF). This study models such an interactive process of scaffold degradation and tissue growth, thereby providing some new insights into design of biodegradable scaffold micro-architecture for tissue engineering. PMID: 21529933 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Interaction of olfactory ensheathing cells with nerve repairing scaffolds. Zhong Nan Da Xue Xue Bao Yi Xue Ban. 2009 May;34(5):382-7 Authors: Wang Y, Wang Y, Yin Y, Li S, Yan Q, Wan Z, Han Y To investigate a new way to yield plenty of high purity olfactory ensheathing cells (OECs) and its biocompatibility with appropriate scaffolds. PMID: 19483284 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | RalA function in dermal fibroblasts is required for the progression of squamous cell carcinoma of the skin. Cancer Res. 2011 Feb 1;71(3):758-67 Authors: Sowalsky AG, Alt-Holland A, Shamis Y, Garlick JA, Feig LA A large body of evidence has shown that stromal cells play a significant role in determining the fate of neighboring tumor cells through the secretion of various cytokines. How cytokine secretion by stromal cells is regulated in this context is poorly understood. In this study, we used a bioengineered human tissue model of skin squamous cell carcinoma progression to reveal that RalA function in dermal fibroblasts is required for tumor progression of neighboring neoplastic keratinocytes. This conclusion is based on the observations that suppression of RalA expression in dermal fibroblasts blocked tumorigenic keratinocytes from invading into the dermal compartment of engineered tissues and suppressed more advanced tumor progression after these tissues were transplanted onto the dorsum of mice. RalA executes this tumor-promoting function of dermal fibroblasts, at least in part, by mediating hepatocyte growth factor (HGF) secretion through its effector proteins, the Sec5 and Exo84 subunits of the exocyst complex. These findings reveal a new level of HGF regulation and highlight the RalA signaling cascade in dermal fibroblasts as a potential anticancer target. PMID: 21159665 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Engineered cardiac tissues. Curr Opin Biotechnol. 2011 Apr 27; Authors: Iyer RK, Chiu LL, Reis LA, Radisic M Cardiac tissue engineering offers the promise of creating functional tissue replacements for use in the failing heart or for in vitro drug screening. The last decade has seen a great deal of progress in this field with new advances in interdisciplinary areas such as developmental biology, genetic engineering, biomaterials, polymer science, bioreactor engineering, and stem cell biology. We review here a selection of the most recent advances in cardiac tissue engineering, including the classical cell-scaffold approaches, advanced bioreactor designs, cell sheet engineering, whole organ decellularization, stem cell-based approaches, and topographical control of tissue organization and function. We also discuss current challenges in the field, such as maturation of stem cell-derived cardiac patches and vascularization. PMID: 21530228 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Toward label-free Raman-activated cell sorting of cardiomyocytes derived from human embryonic stem cells. J Biomed Opt. 2011 Apr;16(4):045002 Authors: Pascut FC, Goh HT, George V, Denning C, Notingher I Raman micro-spectroscopy (RMS) has been recently proposed for label-free phenotypic identification of human embryonic stem cells (hESC)-derived cardiomyocytes. However, the methods used for measuring the Raman spectra led to acquisition times of minutes per cell, which is prohibitive for rapid cell sorting applications. In this study we evaluated two measurement strategies that could reduce the measurement time by a factor of more than 100. We show that sampling individual cells with a laser beam focused to a line could eliminate the need of cell raster scanning and achieve high prediction accuracies (>95% specificity and >96% sensitivity) with acquisition times ∼5 seconds per cell. However, the use of commercially-available higher power lasers could potentially lead to sorting speeds of ∼10 cells per s. This would start to progress RMS to the field of cell sorting for applications such as enrichment and purification of hESC-derived cardiomyocytes. PMID: 21529069 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of microtopographical cues on human keratocyte orientation and gene expression. Curr Eye Res. 2011 Feb;36(2):88-93 Authors: Then KY, Yang Y, Ahearne M, El Haj AJ To determine if microtopographical cues can influence the orientation and extracellular matrix production of human keratocytes in vitro. PMID: 21281064 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Differences in chemical composition and internal structure influence systemic host response to implants of biomaterials. Int J Artif Organs. 2011 Apr 20; Authors: Scaglione S, Cilli M, Fiorini M, Quarto R, Pennesi G In reconstructive surgery, implantable devices are used to supply a missing function. In tissue engineering, biomaterials serve to guide and eventually deliver cells and/or molecules where a tissue regenerative response is needed. The host organism always reacts to implants of any biomaterial, in some instances even triggering a local cascade of events called the foreign body response (FBR), whose mechanisms are well defined. What has yet to be completely unraveled are the biomarkers systemically mirroring the FBR and the regeneration processes, which would be helpful for assessing the therapeutic efficacy of the bioscaffold. Our goal was to identify a biomarker fingerprint of the systemic reaction of host response to bioscaffold implants. Different biomaterials chosen for their osteoconductive properties, including collagen, hydroxyapatite, in foam or granules, and poly-e-caprolactone, were implanted in immunocompetent mice. We analyzed serum concentrations of cells and cytokines involved in the inflammatory/immune response, and the histological features of grafts. Within two weeks after implantation, a wave of proinflammatory cytokines was flowing in the blood stream and the concentration of blood cells changed, revealing specific patterns depending on the chemistry and structure of the implanted biomaterials. Cells secreting pro-inflammatory, chemoactractant, and pro-angiogenic cytokines required for the early events in tissue repair were locally recruited because of the presence of a bioscaffold. PMID: 21534242 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Magnetic resonance studies of macromolecular content in engineered cartilage treated with pulsed low-intensity ultrasound. Tissue Eng Part A. 2011 Feb;17(3-4):407-15 Authors: Irrechukwu ON, Lin PC, Fritton K, Doty S, Pleshko N, Spencer RG Noninvasive monitoring of matrix development in tissue-engineered cartilage constructs would permit ongoing assessment with the ability to modify culture conditions during development to optimize tissue characteristics. In this study, chondrocytes seeded in a collagen hydrogel were exposed for 20 min/day to pulsed low-intensity ultrasound (PLIUS) at 30 mWcm(-2) and cultured for up to 5 weeks. Biochemical assays, histology, immunohistochemistry, Fourier transform infrared spectroscopy, and magnetic resonance imaging (MRI) were performed at weeks 3 and 5 after initiation of growth. The noninvasive MRI measurements were correlated with those from the invasive studies. In particular, MRI transverse relaxation time (T2) and magnetization transfer rate (k(m)) correlated with macromolecular content, which was increased by application of PLIUS. This indicates the sensitivity of MR techniques to PLIUS-induced changes in matrix development, and highlights the potential for noninvasive assessment of the efficacy of anabolic interventions for engineered tissue. PMID: 20807015 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Vascular organogenesis: dream or reality? Organogenesis. 2010 Jul-Sep;6(3):158-60 Authors: Walpoth BH PMID: 21197217 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Cell sourcing for bone tissue engineering: Amniotic fluid stem cells have a delayed, robust differentiation compared to mesenchymal stem cells. Stem Cell Res. 2011 Mar 21; Authors: Peister A, Woodruff MA, Prince JJ, Gray DP, Hutmacher DW, Guldberg RE Cell based therapies for bone regeneration are an exciting emerging technology, but the availability of osteogenic cells is limited and an ideal cell source has not been identified. Amniotic fluid-derived stem cells (AFS) and bone-marrow derived mesenchymal stem cells (MSCs) were compared to determine their osteogenic differentiation capacity in both 2D and 3D environments. In 2D culture, the AFS cells produced more mineralized matrix but delayed peaks in osteogenic markers. Cells were also cultured on 3D scaffolds constructed of poly-ε-caprolactone for 15weeks. MSCs differentiated more quickly than AFS cells on 3D scaffolds, but mineralized matrix production slowed considerably after 5weeks. In contrast, the rate of AFS cell mineralization continued to increase out to 15weeks, at which time AFS constructs contained 5-fold more mineralized matrix than MSC constructs. Therefore, cell source should be taken into consideration when used for cell therapy, as the MSCs would be a good choice for immediate matrix production, but the AFS cells would continue robust mineralization for an extended period of time. This study demonstrates that stem cell source can dramatically influence the magnitude and rate of osteogenic differentiation in vitro. PMID: 21531647 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Directed differentiation of motor neuron cell-like cells from human adipose-derived stem cells in vitro. Neuroreport. 2011 Jun 11;22(8):370-3 Authors: Liqing Y, Jia G, Jiqing C, Ran G, Fei C, Jie K, Yanyun W, Cheng Z The capacity of human adipose-derived stem cells (hADSCs) to differentiate into motor neurons and the identity of molecular factors that confer hADSCs with the competence of motor neurons have yet to be elucidated. Here, retinoic acid and sonic hedgehog were applied to examine whether hADSCs could be differentiated into motor neurons. As early as 6 h after induction, hADSCs were changed toward neuronal morphology. After induction, hADSCs showed positive immunocytochemical staining for β-III-tubulin, choline acetyltransferase, and neuron-specific enolase. Reverse-transcriptase polymerase chain reaction characterization indicated that cells differentiated from hADSCs were restricted to the ventral spinal fate (Nkx2.2, Pax6, Hb9, and Olig2). Our results suggest that hADSCs may be a potential candidate in cellular therapy for motor neuron disease. PMID: 21532392 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Effects of Combined Mechanical Stimulation on the Proliferation and Differentiation of Pre-Osteoblasts. Exp Mol Med. 2011 May 2; Authors: Kang KS, Lee SJ, Lee H, Moon W, Cho DW We observed how combined mechanical stimuli affect the proliferation and differentiation of pre-osteoblasts. For this research, a bioreactor system was developed that can simultaneously stimulate cells with cyclic strain and ultrasound, each of which is known to effectively stimulate bone tissue regeneration. MC3T3-E1 cells, which are pre-osteoblasts, were chosen for bone tissue engineering due to their osteoblast-like characteristics. 3-D scaffolds were fabricated with PCL and PLLA using the salt leaching method. They were stimulated by the bioreactor with cyclic strain and ultrasound. The bioreactor was set at a frequency of 1.0 Hz and 10 % strain for cyclic strain and 1.0 MHz and 30 mW/cm2 for ultrasound. Three experimental groups (ultrasound, cyclic strain, and combined stimulation) and a control group were examined. Each group was stimulated for 20 min/day. The Cell Counting Kit-8 (CCK-8) results up to 10 days demonstrated that mechanical stimuli did not affect MC3T3-E1 cell proliferation significantly. Gene expression analysis of collagen type-I (COL-I), osteocalcin (OC), RUNX2, and osterix (OSX) indicated that the combined mechanical stimulation accelerates the matrix maturation of MC3T3-E1 cells. Taken together, these results indicate that the combined mechanical stimulation can affect the differentiation of pre-osteoblasts better than simple stimuli, even though cell proliferation did not increase. PMID: 21532314 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Paracrine effects influenced by cell culture medium and consequences on microvessel-like structures in co-cultures of mesenchymal stem cells and outgrowth endothelial cells. Tissue Eng Part A. 2011 Apr 30; Authors: Kolbe M, Xiang Z, Dohle E, Tonak M, Kirkpatrick J, Fuchs S Mesenchymal stem cells (MSC) from bone marrow and outgrowth endothelial cells (OEC) from peripheral blood are considered as attractive cell types for applications in regenerative medicine aiming to build up complex vascularised tissue engineered constructs. MSC provide several advantages such as the potential to differentiate to osteoblasts and to support the neovascularization process by release of proangiogenic factors. On the other hand the neovascularization process can be actively supported by OEC forming perfused vascular structures after co-implantation with other cell types. In this study the formation of angiogenic structures in vitro was investigated in co-cultures of MSC and OEC, cultured either in the medium for osteogenic differentiation of MSC (ODM) or in the medium for OEC cultivation (EGM2 Bullet Kit). After 2 weeks co-cultures in EGM2 formed more microvessel-like structures compared to co-cultures in ODM as demonstrated by immunofluorescence staining for the endothelial marker CD31. An increased expression of CD31 and CD146 in quantitative RT-PCR, as well as a higher percentage of CD31- and CD146- positive cells in flow cytometry indicated a beneficial influence of EGM2 on endothelial cell growth and function. In addition, the improved formation of vascular structures in EGM2 correlates with higher levels of the proangiogenic factor VEGF and PDGF in the supernatant of co-cultures as well as in monocultures of MSC when cultivated in EGM-2. Nevertheless, ODM was more suitable for the differentiation of MSC to osteoblastic lineages in the co-cultures whereas EGM2 favoured factors involved in vessel stabilization by pericytes. In conclusion, this study highlights the importance of medium components for cell interaction triggering the formation of angiogenic structures. PMID: 21529248 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Purine metabolism, immune reconstitution, and abdominal adipose tumor after gene therapy for adenosine deaminase deficiency. J Allergy Clin Immunol. 2011 Apr 28; Authors: Grunebaum E, Chung CT, Dadi H, Kim P, Brigida I, Ferrua F, Cicalese MP, Aiuti A, Roifman CM PMID: 21531016 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The novel BTB/POZ and zinc finger factor Zbtb45 is essential for proper glial differentiation of neural and oligodendrocyte progenitor cells. Cell Cycle. 2010 Dec 15;9(24):4866-75 Authors: Södersten E, Lilja T, Hermanson O Understanding the regulatory mechanisms controlling the fate decisions of neural stem cells (NSCs) is a crucial issue to shed new light on mammalian central nervous system (CNS) development in health and disease. We have investigated a possible role for the previously uncharacterized BTB/POZ-domain containing zinc finger factor Zbtb45 in the differentiation of NSCs and postnatal oligodendrocyte precursors. In situ hybridization histochemistry and RT-qPCR analysis revealed that Zbtb45 mRNA was ubiquitously expressed in the developing CNS in mouse embryos at embryonic day (E) 12.5 and 14.5. Zbtb45 mRNA knockdown in embryonic forebrain NSCs by siRNA resulted in a rapid decrease in the expression of oligodendrocyte-characteristic genes after mitogen (FGF2) withdrawal, whereas the expression of astrocyte-associated genes such as CD44 and GFAP increased compared to control. Accordingly, the number of astrocytes was significantly increased seven days after Zbtb45 siRNA delivery to NSCs, in contrast to the numbers of neuronal and oligodendrocyte-like cells. Surprisingly, mRNA knockdown of the Zbtb45-associated factor Med31, a subunit of the Mediator complex, did not result in any detectable effect on NSC differentiation. Similar to NSCs, Zbtb45 mRNA knockdown in oligodendrocyte precursors (CG-4) reduced oligodendrocyte maturation upon mitogen withdrawal associated with down-regulation of the mRNA expression and protein levels of markers for oligodendrocytic differentiation. Zbtb45 mRNA knockdown did not significantly affect proliferation or cell death in any of the cell types. Based on these observations, we propose that Zbtb45 is a novel regulator of glial differentiation. PMID: 21131782 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Selective elimination of the transformed hepatic stem cells using hybrid liposomes. Yakugaku Zasshi. 2011;131(5):757-63 Authors: Oshikata A, Miyazaki R, Matsushita T, Ueoka R To realize regenerative medicine, it is very important to eliminate the transformed stem cells selectively included in iPS cells, ES cells and adult stem cells derived from organs, because the transformed stem cells have a risk of tumorigenesis after the cell transplantation. Ueoka et al., have developed hybrid liposomes (HL) which selectively accumulated to membranes of tumor cells and have high inhibitory effects on the growth of tumor cells along with the induction of apoptosis. Therefore, we have investigated the application of HL23 (DMPC/10 mol%C(12)(EO)(23)) to the selective elimination of transformed stem cells using hepatoblast, which we could induce from human fetal hepatocytes by the treatment of 1 mM sodium butyrate for 8 days. During the induction process, the transformed cells appeared and produced abnormal prothrombin (PIVKA-II), which is a clinical marker for hepatoma, and also formed colonies in soft agar plate, which is a criteria for neoplastic cell transformation. On the other hand, by the treatment with 0.33 mM HL23 for 96 h during the induction process, PIVKA-II production rate of the cells and colonies formed in the soft agar plate also remarkably decreased less than those of the normal cells. Furthermore, the population of hepatoblasts in the remaining cells increased about four times. These results suggest that the transformed hepatic stem cells could be selectively eliminated by the treatment of HL23, and HL treatment of the stem cells would be a useful culture method for quality control of the stem cells to reduce a risk of tumorigenesis after the cell transplantation. PMID: 21532272 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Tryptophan 2,3-dioxygenase is a key modulator of physiological neurogenesis and anxiety-related behavior in mice. Mol Brain. 2009;2:8 Authors: Kanai M, Funakoshi H, Takahashi H, Hayakawa T, Mizuno S, Matsumoto K, Nakamura T Although nutrients, including amino acids and their metabolites such as serotonin (5-HT), are strong modulators of anxiety-related behavior, the metabolic pathway(s) responsible for this physiological modulation is not fully understood. Regarding tryptophan (Trp), the initial rate-limiting enzymes for the kynurenine pathway of tryptophan metabolism are tryptophan 2,3-dioxygenase (TDO) and indoleamine 2,3-dioxygenase (IDO). Here, we generated mice deficient for tdo (Tdo(-/-)). Compared with wild-type littermates, Tdo(-/-) mice showed increased plasma levels of Trp and its metabolites 5-hydroxyindoleacetic acid (5-HIAA) and kynurenine, as well as increased levels of Trp, 5-HT and 5-HIAA in the hippocampus and midbrain. These mice also showed anxiolytic modulation in the elevated plus maze and open field tests, and increased adult neurogenesis, as evidenced by double staining of BrdU and neural progenitor/neuronal markers. These findings demonstrate a direct molecular link between Trp metabolism and neurogenesis and anxiety-related behavior under physiological conditions. PMID: 19323847 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Acid sphingomyelinase in macrophage biology. Cell Mol Life Sci. 2011 May 2; Authors: Truman JP, Al Gadban MM, Smith KJ, Hammad SM Macrophages play a central role in innate immune responses, in disposal of cholesterol, and in tissue homeostasis and remodeling. To perform these vital functions macrophages display high endosomal/lysosomal activities. Recent studies have highlighted that acid sphingomyelinase (ASMase), which generates ceramide from sphingomyelin, is involved in modulation of membrane structures and signal transduction in addition to its metabolic role in the lysosome. In this review, we bring together studies on ASMase, its different forms and locations that are necessary for the macrophage to accomplish its diverse functions. We also address the importance of ASMase to several disease processes that are mediated by activated macrophages. PMID: 21533981 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Death and inflammation following somatic cell transplantation. Semin Immunopathol. 2011 May 1; Authors: Copland IB, Galipeau J The fields of regenerative medicine and cellular therapy have been the subject of tremendous hype and hope. In particular, the perceived usage of somatic cells like mesenchymal stromal stem cells (MSCs) has captured the imagination of many. Clinical trials are currently evaluating the therapeutic efficacy of MSCs in disorders ranging from heart disease to pediatric graft-vs-host disease; however, numerous questions still remain regarding mechanism of action, effective dose, and whether these cells can be used in the allogeneic setting. One of the major issues surrounding the development of somatic cell therapies like MSCs is that despite evoking a positive response, long-term engraftment and persistence of these cells is rare. Consequently, very large cell doses need be administered raising production, delivery, and efficacy issues. In this review, we will discuss causes for this lack of persistence and highlight some of the methodologies be used to enhance cell survival post-transplantation. PMID: 21533908 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Pathogenesis of Acute Kidney Injury: Foundation for Clinical Practice. Am J Kidney Dis. 2011 Apr 27; Authors: Kinsey GR, Okusa MD The pathogenesis of acute kidney injury (AKI) is complex, involving such factors as vasoconstriction, leukostasis, vascular congestion, cell death, and abnormal immune modulators and growth factors. Many targeted clinical therapies have failed, are inconclusive, or have yet to be tested. Given the complexity of the pathogenesis of AKI, it may be naive to expect that one therapeutic intervention would have success. Some examples of detrimental processes that can be blocked in preclinical models to improve kidney function and survival are apoptotic cell death in tubular epithelial cells, complement-mediated immune system activation, and impairment of cellular homeostasis and metabolism. Modalities with the potential to decrease morbidity and mortality in patients with AKI include vasodilators, growth factors, anti-inflammatory agents, and cell-based therapies. Pharmacologic agents that target these diverse pathways are being used clinically for other indications. Using combinatorial approaches in future clinical trials may improve our ability to prevent and treat AKI. PMID: 21530035 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthesis and biological evaluation of a novel human stem/progenitor cells proliferation activator: 4-(4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenyl) thiosemicarbazide (Stemazole). Eur J Med Chem. 2011 Apr 12; Authors: Sun Y, Wang W, Sun Y, Han M Stem/progenitor cells are crucial for cell-based therapy and regenerative medicine, and their application in clinical and basic research requires a large supply of cells. To identify effective stem/progenitor cell proliferation activators, we synthesised a series of new 4-(4-(5-mercapto-1,3,4-oxadiazol-2-yl)phenyl) thiosemicarbazide (named Stemazole) derivatives. Preliminary evaluation of the structure-activity relationship (SAR) and the biological activities of the compounds were determined with a luminescent cell viability assay. The identified leading compound, Stemazole, exhibited remarkable proliferation-promoting activity in human hippocampal stem/progenitor cells (HSCs) in a time-dependent and concentration-dependent manner. The proliferation-promoting activity of Stemazole was further confirmed against a panel of human stem/progenitor cells derived from each of the three blastoderm layers. In conclusion, Stemazole is a novel activator of stem cells proliferation. PMID: 21531486 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Association of Rex-1 to target genes supports its interaction with Polycomb function. Stem Cell Res. 2011 Mar 2; Authors: Garcia-Tuñon I, Guallar D, Alonso-Martin S, Benito AA, Benítez-Lázaro A, Pérez-Palacios R, Muniesa P, Climent M, Sánchez M, Vidal M, Schoorlemmer J Rex-1/Zfp42 displays a remarkably restricted pattern of expression in preimplantation embryos, primary spermatocytes, and undifferentiated mouse embryonic stem (ES) cells and is frequently used as a marker gene for pluripotent stem cells. To understand the role of Rex-1 in selfrenewal and pluripotency, we used Rex-1 association as a measure to identify potential target genes, and carried out chromatin-immunoprecipitation assays in combination with gene specific primers to identify genomic targets Rex-1 associates with. We find association of Rex-1 to several genes described previously as bivalently marked regulators of differentiation and development, whose repression in mouse embryonic stem (ES) cells is Polycomb Group-mediated, and controlled directly by Ring1A/B. To substantiate the hypothesis that Rex-1 contributes to gene regulation by PcG, we demonstrate interactions of Rex-1 and YY2 (a close relative of YY1) with Ring1 proteins and the PcG-associated proteins RYBP and YAF2, in line with interactions reported previously for YY1. We also demonstrate the presence of Rex-1 protein in both trophectoderm and Inner Cell Mass of the mouse blastocyst and in both ES and in trophectoderm stem (TS) cells. In TS cells, we were unable to demonstrate association of Rex-1 to the genes it associates with in ES cells, suggesting that association may be cell-type specific. Rex-1 might fine-tune pluripotency in ES cells by modulating Polycomb-mediated gene regulation. PMID: 21530438 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal progenitor cells from canine fetal tissues: yolk sac, liver and bone marrow. Tissue Eng Part A. 2011 Apr 30; Authors: Wenceslau CV, Miglino MA, Martins DS, Ambrósio CE, Lizier NF, Pignatari GC, Kerkis I During fetal development mesenchymal progenitor (MP) cells are co-localized in major hematopoietic territories, such as yolk sac (YS), bone marrow (BM), liver (LV) and others. Studies using mouse and human MP cells isolated from fetus have shown that these cells are very similar but not identical to adult mesenchymal stem cells (MSC). Their differentiation potential is usually restricted to production of highly committed osteogenic and chondrogenic precursors. Such properties of fetal MP cells can be very useful for tissue regeneration, when a great number of committed precursors are required. The objectives of this study were to isolate and characterize MP cells from canine YS, BM and LV in early and late stages of fetal development. Gestational stage was identified and cell culture conditions were evaluated for efficient isolation of canine MP cells. All canine fetal MP cells expressed vimentin, nestin and CD44 proteins. Cytokeratin 18 expression was observed in BM- and LV-MP cells and VE-Cadherin expression was observed only in YS-MP cells. A small number of MP cells (5%) from LV and YS expressed Oct3/4 protein. The differentiation potential of canine fetal MP cells varied significantly: YS- and BM-MP cells differentiated into bone and cartilage, while LV-MP cells differentiation was limited to osteogenic fate. None of the canine fetal MP cells were able to differentiate into adipose cells. Our data suggest that canine fetal MP cells are an appropriate in vitro model to study MP biology from hematopoietic territories and they are a source of committed osteogenic and chondrogenic precursors for regenerative medicine. PMID: 21529262 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue-engineered vascular graft remodeling in a growing lamb model: expression of matrix metalloproteinases. Eur J Cardiothorac Surg. 2011 Apr 27; Authors: Cummings I, George S, Kelm J, Schmidt D, Emmert MY, Weber B, Zünd G, Hoerstrup SP Objectives: We have previously demonstrated the functionality and growth of autologous, living, tissue-engineered vascular grafts (TEVGs) in long-term animal studies. These grafts showed substantial in vivo tissue remodeling and approximation to native arterial wall characteristics. Based on this, in vitro and in vivo matrix metalloproteinase (MMP) activity of TEVGs is investigated as a key marker of matrix remodeling. Methods: TEVGs fabricated from biodegradable scaffolds (polyglycolic-acid/poly-4-hydroxybutyrate, PGA/P4HB) seeded with autologous vascular cells were cultured in static and dynamic in vitro conditions. Thereafter, TEVGs were implanted as pulmonary artery replacements in lambs and followed up for 2 years. Gelatin gel zymography to detect MMP-2 and -9 was performed and collagen content quantified (n=5). Latent (pro) and active MMP-2 and -9 were detected. Results: Comparable levels of active MMP-9 and pro-MMP-2 were detected in static and dynamic culture. Higher levels of active MMP-2 were detected in dynamic cultures. Expression of MMP-2 and -9 was minimal in native grafts but was increased in implanted TEVG. Pro-MMP-9 was expressed 20 weeks post implantation and persisted up to 80 weeks post implantation. Collagen content in vitro was increased in dynamically conditioned TEVG as compared with static constructs and was increased in vivo compared with the corresponding native pulmonary artery. Conclusions: MMPs are up-regulated in vitro by dynamic culture conditions and could contribute to increased matrix remodeling, native analogous tissue formation and functional growth of TEVGs in vivo. Monitoring of MMP activity, for example, by molecular imaging techniques, may enable the non-invasive assessment of functional tissue quality in future clinical tissue-engineering applications. PMID: 21530291 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Transplantation of CTLA4Ig gene-transduced adipose tissue-derived mesenchymal stem cells reduces inflammatory immune response and improves Th1/Th2 balance in experimental autoimmune thyroiditis. J Gene Med. 2011 Jan;13(1):3-16 Authors: Choi EW, Shin IS, Lee HW, Park SY, Park JH, Nam MH, Kim JS, Woo SK, Yoon EJ, Kang SK, Ra JC, Youn HY, Hong SH Autoimmune thyroiditis is one of common organ-specific autoimmune disease. The aim of this study was to observe the effect of adipose tissue derived mesenchymal stem cells (ATMSC) and CTLA4Ig gene-transduced ATMSC on autoimmune thyroiditis. PMID: 21259404 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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