|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | EGFR signalling regulates cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. Dev Biol. 2011 Mar 30; Authors: Fraguas S, Barberán S, Cebrià F Similarly to development, the process of regeneration requires that cells accurately sense and respond to their external environment. Thus, intrinsic cues must be integrated with signals from the surrounding environment to ensure appropriate temporal and spatial regulation of tissue regeneration. Identifying the signalling pathways that control these events will not only provide insights into a fascinating biological phenomenon but may also yield new molecular targets for use in regenerative medicine. Among classical models to study regeneration, freshwater planarians represent an attractive system in which to investigate the signals that regulate cell proliferation and differentiation, as well as the proper patterning of the structures being regenerated. Recent studies in planarians have begun to define the role of conserved signalling pathways during regeneration. Here, we extend these analyses to the epidermal growth factor (EGF) receptor pathway. We report the characterization of three epidermal growth factor (EGF) receptors in the planarian Schmidtea mediterranea. Silencing of these genes by RNA interference (RNAi) yielded multiple defects in intact and regenerating planarians. Smed-egfr-1(RNAi) resulted in decreased differentiation of eye pigment cells, abnormal pharynx regeneration and maintenance, and the development of dorsal outgrowths. In contrast, Smed-egfr-3(RNAi) animals produced smaller blastemas associated with abnormal differentiation of certain cell types. Our results suggest important roles for the EGFR signalling in controlling cell proliferation, differentiation and morphogenesis during planarian regeneration and homeostasis. PMID: 21458439 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gene therapy for leukodystrophies. Hum Mol Genet. 2011 Mar 31; Authors: Biffi A, Aubourg P, Cartier N Leukodystrophies refers to a group on inherited diseases in which molecular abnormalities of glial cells are responsible for exclusive or predominant defects in myelin formation and/or maintenance within the central and, sometimes, the peripheral nervous system. For three of them (X-linked adrenoleukodystrophy, metachromatic and globoid cell leukodystrophies), a gene therapy strategy aiming at transferring the disease gene into autologous hematopoietic stem cells using lentiviral vectors has been developed and has already entered into the clinics for X-linked adrenoleukodystrophy and metachromatic leukodystrophy. Long-term follow-up has shown that hematopoietic stem cells gene therapy can arrest the devastating progression of X-linked adrenoleukodystrophy. Brain gene therapy relying upon intracerebral injections of adeno-associated vectors is also envisaged for metachromatic leukodystrophy. The development of new gene therapy viral vectors allowing targeting of the disease gene into oligodendrocytes or astrocytes should soon benefit other forms of leukodystrophies. PMID: 21459776 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Induced pluripotent stem cells: A new technology to study human diseases. Int J Biochem Cell Biol. 2011 Mar 30; Authors: Vitale AM, Wolvetang E, Mackay-Sim A Induced pluripotent stem cells (iPS cells) are somatic cells that have been reprogrammed to a pluripotent state by the introduction of specific factors. They can be generated from cells of different origins such as fibroblasts, keratinocytes, hepatocytes and blood. iPS cells are similar to embryonic stem cells in several aspects such as morphology, expression of pluripotency markers and the capacity to develop teratomas; tumors containing cells of the three germ layers. As pluripotent stem cells they can be differentiated into several lineages including neuronal, cardiac and blood cells. Recently, several groups have successfully generated patient-specific iPS cells from donors suffering different disorders and differentiated them into the cell type affected by the disease. These new human cell-based models cannot only be used to study the dynamics of diseases but also as systems to screen new drugs. Moreover, iPS cells promise to be good candidates for regenerative medicine. PMID: 21458591 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cell-based therapies in regenerative medicine: applications in rheumatology. Stem Cell Res Ther. 2011 Mar 18;2(2):14 Authors: Maumus M, Guérit D, Toupet K, Jorgensen C, Noël D ABSTRACT: Growing knowledge on the biology of mesenchymal stem cells (MSCs) has provided new insights into their potential clinical applications, particularly for rheumatologic disorders. Historically, their potential to differentiate into cells of the bone and cartilage lineages has led to a variety of experimental strategies to investigate whether MSCs can be used for tissue engineering approaches. Beyond this potential, MSCs also display immunosuppressive properties, which have prompted research on their capacity to suppress local inflammation and tissue damage in a variety of inflammatory autoimmune diseases and, in particular, in rheumatoid arthritis. Currently, an emerging field of research comes from the possibility that these cells, through their trophic/regenerative potential, may also influence the course of chronic degenerative disorders and prevent cartilage degradation in osteoarthritis. This review focuses on these advances, specifically on the biological properties of MSCs, including their immunoregulatory characteristics, differentiation capacity and trophic potential, as well as the relevance of MSC-based therapies for rheumatic diseases. PMID: 21457518 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cytotoxic Antibody Fragments for Eliminating Undifferentiated Human Embryonic Stem Cells. J Biotechnol. 2011 Mar 30; Authors: Lim DY, Ng YH, Lee J, Mueller M, Choo AB, Wong VV Human embryonic stem cells (hESC) possess great potential for applications in regenerative medicine due to their ability to differentiate into any cell type in the body. However, it is crucial to remove residual undifferentiated hESC from the differentiated population to avoid teratoma formation in vivo. The monoclonal antibody, mAb 84, has been shown to bind and kill undifferentiated hESC and is very useful for the elimination of contaminating undifferentiated hESC prior to transplantation. As mAb 84 is an IgM, its large size may impede penetration into embryoid bodies (EB) or cell clumps. To improve penetration, four antibody fragment formats of mAb 84 were engineered and expressed in Escherichia coli: Fab 84, scFv 84, scFv 84-diabody and scFv 84-HTH. All 4 fragments bound specifically to hESC, but only scFv 84-HTH, a single chain variable fragment with a dimerizing helix-turn-helix motif, could recapitulate the cytotoxicity of mAb 84 on multiple hESC lines. The results suggest that multivalency and flexibility between the antigen-binding sites may be essential features required for killing of hESC by mAb 84 and its derivatives. Imaging of EB treated with scFv 84-HTH or mAb 84 showed an even distribution of scFv 84-HTH throughout the EB whereas mAb 84 was localized more to the periphery. PMID: 21458505 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | FGF4-dependent stem cells derived from rat blastocysts differentiate along the trophoblast lineage. Dev Biol. 2011 Mar 1;351(1):110-9 Authors: Asanoma K, Rumi MA, Kent LN, Chakraborty D, Renaud SJ, Wake N, Lee DS, Kubota K, Soares MJ Differentiated trophoblast cell lineages arise from trophoblast stem (TS) cells. To date such a stem cell population has only been established in the mouse. The objective of this investigation was to establish TS cell populations from rat blastocysts. Blastocysts were cultured individually on a feeder layer of rat embryonic fibroblasts (REFs) in fibroblast growth factor-4 (FGF4) and heparin supplemented culture medium. Once cell colonies were established REF feeder layers could be replaced with REF conditioned medium. The blastocyst-derived cell lines, in either proliferative or differentiated states, did not express genes indicative of ICM-derived tissues. In the proliferative state the cells expressed established stem cell-associated markers of TS cells. Cells ceased proliferation and differentiated when FGF4, heparin, and REF conditioned medium were removed. Differentiation was characterized by a decline of stem cell-associated marker gene expression, the appearance of large polyploid cells (trophoblast giant cells), and the expression of trophoblast differentiation-associated genes. Collectively, the data indicate that the rat blastocyst-derived cell lines not only possess many features characteristic of mouse TS cells but also possess some distinct properties. These rat TS cell lines represent valuable new in vitro models for analyses of mechanisms controlling TS cell renewal and differentiation. PMID: 21215265 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Recruitment of host's progenitor cells to sites of human amniotic fluid stem cells implantation. Biomaterials. 2011 Apr 1; Authors: Teodelinda M, Alessandro P, Monica S, Massimo M, Mario L, Chiara B, Ranieri C, Chiara G The amniotic fluid is a new source of multipotent stem cells with a therapeutic potential for human diseases. Cultured at low cell density, human amniotic fluid stem cells (hAFSCs) were still able to generate colony-forming unit-fibroblast (CFU-F) after 60 doublings, thus confirming their staminal nature. Moreover, after extensive in vitro cell expansion hAFSCs maintained a stable karyotype. The expression of genes, such as SSEA-4, SOX2 and OCT3/4 was confirmed at early and later culture stage. Also, hAFSCs showed bright expression of mesenchymal lineage markers and immunoregulatory properties. hAFSCs, seeded onto hydroxyapatite scaffolds and subcutaneously implanted in nude mice, played a pivotal role in mounting a response resulting in the recruitment of host's progenitor cells forming tissues of mesodermal origin such as fat, muscle, fibrous tissue and immature bone. Implanted hAFSCs migrated from the scaffold to the skin overlying implant site but not to other organs. Given their in vivo: (i) recruitment of host progenitor cells, (ii) homing towards injured sites and (iii) multipotentiality in tissue repair, hAFSCs are a very appealing reserve of stem cells potentially useful for clinical application in regenerative medicine. PMID: 21459439 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Antimicrobial functionalized genetically engineered spider silk. Biomaterials. 2011 Mar 30; Authors: Gomes SC, Leonor IB, Mano JF, Reis RL, Kaplan DL Genetically engineered fusion proteins offer potential as multifunctional biomaterials for medical use. Fusion or chimeric proteins can be formed using recombinant DNA technology by combining nucleotide sequences encoding different peptides or proteins that are otherwise not found together in nature. In the present study, three new fusion proteins were designed, cloned and expressed and assessed for function, by combining the consensus sequence of dragline spider silk with three different antimicrobial peptides. The human antimicrobial peptides human neutrophil defensin 2 (HNP-2), human neutrophil defensins 4 (HNP-4) and hepcidin were fused to spider silk through bioengineering. The spider silk domain maintained its self-assembly features, a key aspect of these new polymeric protein biomaterials, allowing the formation of β-sheets to lock in structures via physical interactions without the need for chemical cross-linking. These new functional silk proteins were assessed for antimicrobial activity against Gram -Escherichia coli and Gram + Staphylococcus aureus and microbicidal activity was demonstrated. Dynamic light scattering was used to assess protein aggregation to clarify the antimicrobial patterns observed. Attenuated-total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and circular dichroism (CD) were used to assess the secondary structure of the new recombinant proteins. In vitro cell studies with a human osteosarcoma cell line (SaOs-2) demonstrated the compatibility of these new proteins with mammalian cells. PMID: 21458065 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effects of histocompatibility and host immune responses on the tumorigenicity of pluripotent stem cells. Semin Immunopathol. 2011 Apr 4; Authors: Dressel R Pluripotent stem cells hold great promises for regenerative medicine. They might become useful as a universal source for a battery of new cell replacement therapies. Among the major concerns for the clinical application of stem cell-derived grafts are the risks of immune rejection and tumor formation. Pluripotency and tumorigenicity are closely linked features of pluripotent stem cells. However, the capacity to form teratomas or other tumors is not sufficiently described by inherited features of a stem cell line or a stem cell-derived graft. The tumorigenicity always depends on the inability of the recipient to reject the tumorigenic cells. This review summarizes recent data on the tumorigenicity of pluripotent stem cells in immunodeficient, syngeneic, allogeneic, and xenogeneic hosts. The effects of immunosuppressive treatment and cell differentiation are discussed. Different immune effector mechanisms appear to be involved in the rejection of undifferentiated and differentiated cell populations. Elements of the innate immune system, such as natural killer cells and the complement system, which are active also in syngeneic recipients, appear to preferentially reject undifferentiated cells. This effect could reduce the risk of tumor formation in immunocompetent recipients. Cell differentiation apparently increases susceptibility to rejection by the adaptive immune system in allogeneic hosts. The current data suggest that the immune system of the recipient has a major impact on the outcome of pluripotent stem cell transplantation, whether it is rejection, engraftment, or tumor development. This has to be considered when the results of experimental transplantation models are interpreted and even more when translation into clinics is planned. PMID: 21461989 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Assessment of the profiling MicroRNA expression of differentiated and dedifferentiated human adult articular chondrocytes. J Orthop Res. 2011 Apr 1; Authors: Lin L, Shen Q, Zhang C, Chen L, Yu C MicroRNA has an important role in regulating gene expression during cell differentiation. In this study we identified the expression pattern of microRNA in the differentiated and dedifferentiated chondrocytes. Adult human articular chondrocytes were cultured in monolayer. RNA was isolated from the differentiated chondrocytes (collected after isolation) and the fifth-passage (dedifferentiated) chondrocytes, and subjected to gene expression analysis using microRNA and cDNA microarray analysis. Real-time RT-PCR was also performed to confirm the differentially expressed genes. Furthermore, we integrated microRNA and cDNA microarray data together with computational approaches, such as microRNA gene target prediction algorithms, to reveal the role of microRNAs involved in chondrocyte homeostasis. The results showed a dramatic change in expression of microRNA between the two cell types. Thirteen up-regulated and 12 down-regulated microRNAs were detected in differentiated chondroctes. We also revealed microRNA-gene target pairs potentially involved in dedifferentiation process. Our results revealed novel findings of differential expression of microRNA in dedifferentiation, and microRNA could have an important role in the maintenance of chondrocytes homeostasis. MicroRNA may be a target for cartilage tissue engineering and regenerative medicine. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 21462252 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro immunogenicity of undifferentiated pluripotent stem cells (PSC) and derived lineages. Semin Immunopathol. 2011 Apr 5; Authors: Kadereit S, Trounson A The observation that embryonic stem cells (ESCs) expressed reduced levels of major histocompatibility (MHC) class I genes, no MHC class II or costimulatory molecules suggested early on that pluripotent stem cells (PSCs) could be "immune-privileged" and were unable to induce immune reactions. However, soon it became apparent that in some instances, ESCs were recognized by immune cells but still could reduce an active and strong immune response. Similar results were obtained with other PSCs. Almost 10 years later, the exact mechanisms are still not well understood and seem to differ between the different human and rodent PSC lines (even between different murine cell lines). These differences could be due to differing experimental approaches, different derivation protocols (to obtain the PSC lines), species specificity, or genetic background of the cells lines. A better understanding of the immune regulatory mechanisms deployed by PSCs and early derivates may inform us on immune regulation and could be exploitable for regenerative medicine using allogeneic cells. As PSCs grow robustly in culture and can easily be gene-modified, one could envision the generation of cell lines that maintain these immune suppressive properties through terminal differentiation, thus generating universal donor cells. PMID: 21461990 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Method for autologous single skin cell isolation for regenerative cell spray transplantation with non-cultured cells. Int J Artif Organs. 2011 Apr 1; Authors: Gerlach JC, Johnen C, Ottoman C, Bräutigam K, Plettig J, Belfekroun C, Münch S, Hartmann B Background: There is a therapeutic gap for patients with deep partial thickness wounds (Grade IIb) of moderate size that were initially not treated with split- or mesh grafting to avoid overgrafting, but developed delayed wound healing around two weeks after injury - at which time grafting is typically not indicated anymore. Delayed wound healing is often associated with esthetically unsatisfactory results and sometimes functional problems. An innovative cell isolation method for cell spray transplantation at the point of care, which eliminates cell culture prior to treatment, was implemented for this population of burn patients in our center. Methods: Autologous skin cell spray transplantation was initiated by taking healthy skin. The dermal/epidermal layers were separated using enzymatic digestion with 40 min dispase application, followed by 15 min trypsin application for basal kerationcyte isolation, 7 min cell washing by centrifugation, followed by transferring the cells for spraying into Ringer lactate solution. The procedure was performed on site in a single session immediately following the biopsy. After sharp wound debridement, cells were immediately transplanted by deposition with a cell sprayer for even distribution of the cell suspension. Results and conclusions: Eight patients were treated (mean age 30.3 years, mean burn total body surface area 14%, mean Abbreviated Burn Severity Index (5 points). The mean time to complete re-epithelialization was 12.6 days. All patients exhibited wound healing with improved esthetic and functional quality. Our initial experience for the use of non-cultured cells using a two-enzyme approach with cell washing suggests shortened time for wound closure, suggesting that the method may potentially avoid longer-term complications. PMID: 21462146 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | The California stem cell agency this spring will be looking into both imaging technology for cellular therapies and ethical/policy questions dealing with reprogrammed stem cells.
The iPSC session April 29 in Los Angeles involves CIRM's Standards Working Group, which makes recommendations for rules for the agency's $3 billion research program. The meeting is a continuation of last year's | | | | | | | | | | | | | | | | | | | | | | | | | Dual-functional composite with anticoagulant and antibacterial properties based on heparinized silk fibroin and chitosan. Colloids Surf B Biointerfaces. 2011 Mar 8; Authors: Wang J, Hu W, Liu Q, Zhang S Heparinized biomaterials exhibit great anticoagulant properties. However, they promote proliferation of Staphylococcus aureus (S. aureus) and therefore cause infection within the bloodstream upon implantation in vivo. In the present study, an interesting dual-functional composite with anticoagulant and antibacterial properties based on heparinized silk fibroin and chitosan was synthesized. First, heparin was grafted onto the silk fibroin by covalent immobilization with N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) and N-hydroxysuccinimide (NHS). All data gathered from Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and elemental analysis (EA) indicated that the heparin was successfully immobilized onto the silk fibroin. The dual-functional composite of heparinized silk fibroin and chitosan was then fabricated by a blending method. The anticoagulant activity of the heparinized materials was evaluated using the prothrombin time (PT), activated partial thromboplastin time (APTT) and thrombin time (TT). The results showed that both heparinized silk fibroin and the composite material exhibited better hemocompatibility in comparison with single silk fibroin or chitosan. The antibacterial property of the materials was investigated by the pour-plate method. Results further suggested that the composite antibacterial property with respect to S. aureus was significantly enhanced. The dual-functionality of the composite material may supply a potential choice in blood contact devices. PMID: 21459560 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cell response to collagen-calcium phosphate cement scaffolds investigated for nonviral gene delivery. J Mater Sci Mater Med. 2011 Apr 3; Authors: Perez RA, Ginebra MP, Spector M Collagen-hydroxyapatite (HA) scaffolds for the non-viral delivery of a plasmid encoding the osteoinductive protein bone morphogenetic protein (BMP)-7 were developed. The collagen-HA was obtained by the combination of calcium phosphate cement in a collagen template. The effect on cell behavior of increasing amounts of HA in the scaffolds was evaluated. Collagen-HA scaffolds containing 13, 23 or 83 wt% HA were prepared. Cell proliferation was reduced in the 83% HA scaffold after 1 day compared to 13 and 23% HA, but by 14 days the number of cells in 83% HA considerably increased. Alkaline phosphatase (ALP) activity was 8 times higher for the 83% HA scaffolds. BMP-7 plasmid was incorporated into the 83% HA scaffold. The transfection was low, although significant levels of BMP7 were expressed, associated with an increase in cell proliferation. PMID: 21461916 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Control of gene transfer on a DNA-fibronectin-apatite composite layer by the incorporation of carbonate and fluoride ions. Biomaterials. 2011 Mar 30; Authors: Yazaki Y, Oyane A, Sogo Y, Ito A, Yamazaki A, Tsurushima H Gene transfer techniques are useful tools for controlling cell behavior, such as proliferation and differentiation. We have recently developed an efficient area-specific gene transfer system using a DNA-fibronectin-apatite composite layer (DF-Ap layer). In this system, partial dissolution of the composite layer is likely to be a crucial step for gene transfer. In the present study, layer solubility was adjusted by incorporating various contents of carbonate or fluoride ions into the DF-Ap layer via ionic substitution for the apatite crystals. Carbonate ion incorporation increased the solubility of the DF-Ap layer, thereby increasing the efficiency of gene transfer on the layer. In contrast, the incorporation of fluoride ions decreased the solubility of the DF-Ap layer, thereby decreasing the efficiency and delaying the timing of gene transfer on the layer dose-dependently. The present gene transfer system with controllable efficiency and timing would be useful in tissue engineering applications because cell differentiation can be induced effectively by regulating appropriate gene expression with suitable timing. PMID: 21458066 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Antimicrobial functionalized genetically engineered spider silk. Biomaterials. 2011 Mar 30; Authors: Gomes SC, Leonor IB, Mano JF, Reis RL, Kaplan DL Genetically engineered fusion proteins offer potential as multifunctional biomaterials for medical use. Fusion or chimeric proteins can be formed using recombinant DNA technology by combining nucleotide sequences encoding different peptides or proteins that are otherwise not found together in nature. In the present study, three new fusion proteins were designed, cloned and expressed and assessed for function, by combining the consensus sequence of dragline spider silk with three different antimicrobial peptides. The human antimicrobial peptides human neutrophil defensin 2 (HNP-2), human neutrophil defensins 4 (HNP-4) and hepcidin were fused to spider silk through bioengineering. The spider silk domain maintained its self-assembly features, a key aspect of these new polymeric protein biomaterials, allowing the formation of β-sheets to lock in structures via physical interactions without the need for chemical cross-linking. These new functional silk proteins were assessed for antimicrobial activity against Gram -Escherichia coli and Gram + Staphylococcus aureus and microbicidal activity was demonstrated. Dynamic light scattering was used to assess protein aggregation to clarify the antimicrobial patterns observed. Attenuated-total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and circular dichroism (CD) were used to assess the secondary structure of the new recombinant proteins. In vitro cell studies with a human osteosarcoma cell line (SaOs-2) demonstrated the compatibility of these new proteins with mammalian cells. PMID: 21458065 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Assessment of the profiling MicroRNA expression of differentiated and dedifferentiated human adult articular chondrocytes. J Orthop Res. 2011 Apr 1; Authors: Lin L, Shen Q, Zhang C, Chen L, Yu C MicroRNA has an important role in regulating gene expression during cell differentiation. In this study we identified the expression pattern of microRNA in the differentiated and dedifferentiated chondrocytes. Adult human articular chondrocytes were cultured in monolayer. RNA was isolated from the differentiated chondrocytes (collected after isolation) and the fifth-passage (dedifferentiated) chondrocytes, and subjected to gene expression analysis using microRNA and cDNA microarray analysis. Real-time RT-PCR was also performed to confirm the differentially expressed genes. Furthermore, we integrated microRNA and cDNA microarray data together with computational approaches, such as microRNA gene target prediction algorithms, to reveal the role of microRNAs involved in chondrocyte homeostasis. The results showed a dramatic change in expression of microRNA between the two cell types. Thirteen up-regulated and 12 down-regulated microRNAs were detected in differentiated chondroctes. We also revealed microRNA-gene target pairs potentially involved in dedifferentiation process. Our results revealed novel findings of differential expression of microRNA in dedifferentiation, and microRNA could have an important role in the maintenance of chondrocytes homeostasis. MicroRNA may be a target for cartilage tissue engineering and regenerative medicine. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 21462252 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human treated dentin matrix as a natural scaffold for complete human dentin tissue regeneration. Biomaterials. 2011 Mar 30; Authors: Li R, Guo W, Yang B, Guo L, Sheng L, Chen G, Li Y, Zou Q, Xie D, An X, Chen Y, Tian W An essential aspect of tooth tissue engineering is the identification of suitable scaffolding materials to support cell growth and tissue regeneration. Treated dentin matrix (TDM) from a rat has recently been shown to be a suitable scaffold for rat dentin regeneration. However, due to species-specific differences, it remains unclear whether a similar fabrication method can be extended to human TDM and human dentin regeneration. Therefore, this present study explored the biological response to a human TDM (hTDM) created using a modified dentin treatment method. Various biological characteristics, including cell proliferation, cell migration, cell viability, and cytotoxity were investigated. To assess the inductive capacity of hTDM, dental follicle cells (DFCs) were combined with hTDM and were implanted in vivo for 8 weeks in a mouse model. The resulting grafts were studied histologically. The results showed hTDM released dentinogenic factors, indicating that hTDM could play a sustained role in odontogenesis. DFC attachment, growth, viability, and cytotoxicity on the surface of hTDM showed a notable improvement over those on calcium phosphate controls. Most importantly, in vivo hTDM induced and supported regeneration of complete dentin tissues, which expressed dentin markers DSP and DMP-1. As cells in and around the regenerated dentin were positive for human mitochondria, implanted DFCs and hTDM were responsible for the regenerated dentin tissues. In conclusion, hTDM is indicated as an ideal biomaterial for human dentin regeneration. PMID: 21458067 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Covalent RGD Modification of the Inner Pore Surface of Polycaprolactone Scaffolds. J Biomater Sci Polym Ed. 2011 Mar 31; Authors: Gabriel M, Nazmi K, Dahm M, Zentner A, Vahl CF, Strand D Scaffold production for tissue engineering was demonstrated by means of a hot compression molding technique and subsequent particulate leaching. The utilization of spherical salt particles as the pore-forming agent ensured complete interconnectivity of the porous structure. This method obviated the use of potentially toxic organic solvents. To overcome the inherent non-cell-adhesive properties of the hydrophobic polymer polycaprolactone (PCL) surface activation with a diamine was performed, followed by the covalent immobilization of the adhesion-promoting RGD-peptide. The wet-chemical approach was performed to guarantee modification throughout the entire scaffold structure. The treatment was characterized by means of chemical and physical methods with respect to an exclusive surface modification without altering the bulk properties of the polymer. RGD-modified scaffolds were tested in cell-culture experiments to investigate the initial attachment and the proliferation of three different cell types. PMID: 21457620 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Alginate combined calcium phosphate cements: mechanical properties and in vitro rat bone marrow stromal cell responses. J Mater Sci Mater Med. 2011 Apr 2; Authors: Lee GS, Park JH, Won JE, Shin US, Kim HW Here, we prepared self-setting calcium phosphate cements (CPCs) based on α-tricalcium phosphate with the incorporation of sodium alginate, and their mechanical properties and in vitro cellular responses were investigated. The addition of alginate enhanced the hardening reaction of CPCs showing shorter setting times within a range of powder-to-liquid ratios. When immersed in a body simulating fluid the alginate-CPCs fully induced a formation of an apatite crystalline phase similar to that of bare CPCs. The compressive and tensile strengths of the CPCs were found to greatly improve during immersion in the fluid, and this improvement was more pronounced in the alginate-CPCs. As a result, the alginate-CPCs retained significantly higher strength values than the bare CPCs after 3-7 days of immersion. The rat bone marrow derived stromal cells (rBMSCs) cultured on the alginate-CPCs initially adhered to and then spread well on the cements surface, showed an on-going increase in the population with culture time, and differentiated into osteoblasts expressing bone-associated genes (collagen type I, osteopontin and bone sialoprotein) and synthesizing alkaline phosphatase. However, the stimulated level of osteogenic differentiation was not confirmative with the incorporation of alginate into the CPC composition based on the results. One merit of the use of alginate was its usefulness in forming CPCs into a variety of scaffold shapes including microspheres and fibers, which is associated with the cross-link of alginate under the calcium-containing solution. PMID: 21461700 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human adipose derived stem cells reduce callus volume upon BMP-2 administration in bone regeneration. Injury. 2011 Mar 30; Authors: Keibl C, Fügl A, Zanoni G, Tangl S, Wolbank S, Redl H, van Griensven M INTRODUCTION: The demand for new therapeutic approaches to treat bone defects and fractures is increasing in trauma surgery and orthopaedics because the number of patients with degenerative diseases is continuously growing. "Tissue Engineering" offers promising new technologies that combine the three components - cells, growth factors and matrix. Efforts are targeted at improving and accelerating recovery, especially for long bone fractures, and reducing the risk of delayed bone healing or pseudoarthrosis. Adult human adipose-derived stem cells (ASC) can differentiate into osteoblasts in an osteogenic surrounding. Bone morphogenetic protein-2 (BMP-2) accelerates and initiates this differentiation. Fibrin, a matrix that promotes wound healing, is a promising carrier for ASCs and BMP-2. MATERIALS AND METHODS: In this study, a 2mm transcortical drill hole in the femur of male rats served as a small non-critical size defect model for fracture simulation. In vivo bone healing was investigated upon administration of the growth factor BMP-2 embedded with ASCs in a locally applied fibrin matrix. Groups with the components alone were also investigated. After 2 and 4 weeks, μCT and histology were performed to determine the bone and callus volume. RESULTS AND DISCUSSION: After only a short period of time (2 and 4 weeks), this animal model discloses comparative information about the osteogenetic potential and bone regeneration with little effort (no osteosynthesis necessary). The most significant result found in this model is that the combination of ASCs and BMP-2 in a fibrin matrix significantly reduces callus formation after 2 weeks compared to BMP-2 alone. BMP-2 alone significantly increased callus formation. ASCs embedded alone in the fibrin matrix did not lead to increased bone regeneration. CONCLUSION: Transplantation of ASC modulated the callus induction by BMP-2 to a normal volume. PMID: 21457972 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Flexor Tendon Tissue Engineering: Acellularization of Human Flexor Tendons With Preservation of Biomechanical Properties and Biocompatibility. Tissue Eng Part C Methods. 2011 Apr 2; Authors: Pridgen BC, Woon CY, Kim MY, Thorfinn J, Lindsey DP, Pham H, Chang J Objective: Acellular human tendons are a candidate scaffold for tissue engineering flexor tendons of the hand. This study compared acellularization methods and their compatibility with allogeneic human cells. Method: Human flexor tendons were pre-treated with 0.1% ethylenediaminetetracetic acid (EDTA) for four hours followed by twenty four hour treatments of 1% Triton X-100, 1% tri(n-butyl)phosphate (TnBP), or 0.1% or 1% sodium dodecyl sulfate (SDS) in 0.1% EDTA. Outcomes were assessed histologically by hematoxylin and eosin and SYTO green fluorescent nucleic acid stains and biochemically by a QIAGEN DNeasy kit, Sircol collagen assay, and 1,9 dimethylmethylene blue glycosaminoglycan assay. Mechanical data were collected using a Materials Testing System to pull to failure tendons acellularized with 0.1% SDS. Acellularized tendons were re-seeded in a suspension of human dermal fibroblasts. Attachment of viable cells to acellularized tendon was assessed biochemically by a cell viability assay and histologically by a live/dead stain. Data are reported as mean ± standard deviation. Result: Compared to the DNA content of fresh tendons (551±212 ng DNA/mg tendon), only SDS treatments significantly decreased DNA content [1% SDS (202.8±37.4 ng DNA/mg dry weight tendon); 0.1% SDS (189±104 ng DNA/mg tendon)]. These findings were confirmed by histology. There was no decrease in glycosaminoglycans or collagen following acellularization with SDS. There was no difference in the ultimate tensile stress [55.3±19.2 (fresh) vs. 51.5±6.9 (0.1% SDS) MPa]. Re-seeded tendons demonstrated attachment of viable cells to the tendon surface using a viability assay and histology. Conclusion: Human flexor tendons were acellularized with 0.1% SDS in 0.1% EDTA for 24 hours with preservation of mechanical properties. Preservation of collagen and glycoaminoglycans and re-seeding with human cells suggest this scaffold is biocompatible. This will provide a promising scaffold for future human flexor tendon tissue engineering studies to further assess biocompatibility through cell proliferation and in vivo studies. PMID: 21457101 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Expansion and preservation of multipotentiality of rabbit bone-marrow derived mesenchymal stem cells in dextran-based microcarrier spin culture. J Mater Sci Mater Med. 2011 Apr 2; Authors: Boo L, Selvaratnam L, Tai CC, Ahmad TS, Kamarul T The use of mesenchymal stem cells (MSCs) in tissue repair and regeneration despite their multipotentiality has been limited by their cell source quantity and decelerating proliferative yield efficiency. A study was thus undertaken to determine the feasibility of using microcarrier beads in spinner flask cultures for MSCs expansion and compared to that of conventional monolayer cultures and static microcarrier cultures. Isolation and characterization of bone marrow derived MSCs were conducted from six adult New Zealand white rabbits. Analysis of cell morphology on microcarriers and culture plates at different time points (D0, D3, D10, D14) during cell culture were performed using scanning electron microscopy and bright field microscopy. Cell proliferation rates and cell number were measured over a period of 14 days, respectively followed by post-expansion characterization. MTT proliferation assay demonstrated a 3.20 fold increase in cell proliferation rates in MSCs cultured on microcarriers in spinner flask as compared to monolayer cultures (p < 0.05). Cell counts at day 14 were higher in those seeded on stirred microcarrier cultures (6.24 ± 0.0420 cells/ml) × 10(5) as compared to monolayer cultures (0.22 ± 0.004 cells/ml) × 10(5) and static microcarrier cultures (0.20 ± 0.002 cells/ml) × 10(5). Scanning electron microscopy demonstrated an increase in cell colonization of the cells on the microcarriers in stirred cultures. Bead-expanded MSCs were successfully differentiated into osteogenic and chondrogenic lineages. This system offers an improved and efficient alternative for culturing MSCs with preservation to their phenotype and multipotentiality. PMID: 21461701 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In-vitro Biodegradability and Mechanical Properties of Bioabsorbable Bacterial Cellulose Incorporating Cellulases. Acta Biomater. 2011 Mar 31; Authors: Hu Y, Catchmark JM Bacterially produced cellulose is being actively studied as a novel scaffold material for wound care and tissue engineering applications. Bioabsorbability of the scaffold material is desired to enable improved restoration of targeted tissue. Recently, a bioabsorbable bacterial cellulose has been demonstrated by incorporating cellulase enzymes. It was revealed that some cellulases may lose up to 90% of their activity if present in a suboptimal pH environment. Therefore, a key challenge in the practical implementation of this approach rests in compensating for the variation of the wound or tissue pH that may significantly reduce the activity of some enzymes. In this work, buffer ingredients were incorporated into the bacterial cellulose in order to create a more optimal pH microenvironment for the preferred acid cellulases, which are significantly less active at the biological pH 7.4. The results demonstrated that incorporation of buffer ingredients helped to retain the activity of the cellulases. The glucose released from degraded materials was also increased from 30% without incorporation of buffer ingredients to 97% in the presence of incorporated buffer ingredients at the suboptimal pH environment of 7.4. The use of simulated body fluid and simulated tissue padding, both mimicking the real wound environment, also demonstrated some improvements for material degradation. Measurements of mechanical properties of materials revealed that bioabsorbable bacterial cellulose materials had the tensile strength and extensibility similar to human skin, especially when hydrated with saline water prior to use. PMID: 21459165 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The role of bFGF in down-regulating α-SMA expression of chondrogenically induced BMSCs and preventing the shrinkage of BMSC engineered cartilage. Biomaterials. 2011 Apr 1; Authors: Li Q, Liu T, Zhang L, Liu Y, Zhang W, Liu W, Cao Y, Zhou G Bone marrow stromal cells (BMSCs) have proved to be an ideal cell source for cartilage regeneration. Our previous studies demonstrated that a three-dimensional (3D) cartilage could be constructed successfully in vitro using BMSCs and biodegradable scaffolds. However, an obvious shrinkage and deformation was observed during in vitro chondrogenic induction. According to the literatures, it can be speculated that the up-regulation of smooth muscle actin-alpha (α-SMA) caused by transforming growth factor beta (TGFβ) is one of the leading reasons and that basic fibroblast growth factor (bFGF) could antagonize the role of TGFβ to down-regulate α-SMA expression and prevent the shrinkage of BMSC engineered cartilage. This study testified these speculations by adding bFGF to chondrogenic media. According to the current results, chondrogenic induction significantly up-regulated α-SMA expression of BMSCs at both cell and tissue levels, and the engineered tissue only retained 12.4% of original size after 6 weeks of chondrogenic induction. However, the supplement of bFGF in chondrogenic media efficiently down-regulated α-SMA expression and the engineered tissue still retained over 60% of original size after 6 weeks of culture. Moreover, bFGF showed a beneficial influence on 3D cartilage formation of BMSCs in terms of gene expression and deposition of cartilage specific matrices. All these results suggested that bFGF could repress α-SMA expression caused by chondrogenic induction, efficiently prevent shrinkage of BMSC engineered tissue, and have a positive influence on cartilage formation, which provides a clue for both shape control and quality improvement of BMSC engineered 3D cartilage. PMID: 21459437 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cell-based therapies in regenerative medicine: applications in rheumatology. Stem Cell Res Ther. 2011 Mar 18;2(2):14 Authors: Maumus M, Guérit D, Toupet K, Jorgensen C, Noël D ABSTRACT: Growing knowledge on the biology of mesenchymal stem cells (MSCs) has provided new insights into their potential clinical applications, particularly for rheumatologic disorders. Historically, their potential to differentiate into cells of the bone and cartilage lineages has led to a variety of experimental strategies to investigate whether MSCs can be used for tissue engineering approaches. Beyond this potential, MSCs also display immunosuppressive properties, which have prompted research on their capacity to suppress local inflammation and tissue damage in a variety of inflammatory autoimmune diseases and, in particular, in rheumatoid arthritis. Currently, an emerging field of research comes from the possibility that these cells, through their trophic/regenerative potential, may also influence the course of chronic degenerative disorders and prevent cartilage degradation in osteoarthritis. This review focuses on these advances, specifically on the biological properties of MSCs, including their immunoregulatory characteristics, differentiation capacity and trophic potential, as well as the relevance of MSC-based therapies for rheumatic diseases. PMID: 21457518 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of human oral mucosal epithelial cell sheets for treatment of esophageal ulceration by endoscopic submucosal dissection. Gastrointest Endosc. 2010 Dec;72(6):1253-9 Authors: Takagi R, Murakami D, Kondo M, Ohki T, Sasaki R, Mizutani M, Yamato M, Nishida K, Namiki H, Yamamoto M, Okano T Esophageal stenosis is one of the major complications of aggressive endoscopic resection. Tissue-engineered epithelial cell grafts have demonstrated effectiveness in promoting re-epithelialization and suppressing inflammation causing esophageal scarring and stenosis after endoscopic submucosal dissection (ESD) in an animal model. PMID: 20970796 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [Tissue engineering of vascular prostheses.] Chirurg. 2011 Apr;82(4):303-310 Authors: Walpoth BH, Möller M Vascular tissue engineering represents a new but rapidly growing field due to the need for better vascular prostheses for coronary or peripheral revascularization procedures. Current synthetic prostheses have a high incidence of failure due to thrombosis and/or intimal hyperplasia especially in small caliber artificial vascular prostheses. New approaches such as decellularized, natural or synthetic, 3-D stable/degradable scaffolds are being developed for acellular or cell-based vascular replacements. The drawbacks of cellular bioreactor matured prostheses are delayed availability and that they are, labor and cost-intensive. However, some research groups have shown limited clinical applications. The acellular approach is based on a biodegradable, electrospun, porous 3-D structure made of nano- and micro-sized polycaprolactone fibers. Animal studies in rats and pigs have shown good short and long-term results after arterial replacement with autologous cellular and matrix ingrowth, angiogenesis, confluent endothelialization and absence of occlusions or aneurysm formation. Therefore, the in vivo vascular tissue engineering approach produces shelf-ready biodegradable vascular prostheses which might be an option for future clinical applications. PMID: 21461795 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro and in vivo characterization of non-biomedical and biomedical grade alginates for articular chondrocyte transplantation. Tissue Eng Part C Methods. 2011 Apr 2; Authors: Heiligenstein S, Cucchiarini M, Laschke MW, Bohle RM, Kohn D, Menger M, Madry H Alginate is a key scaffold for cartilage tissue engineering. Here, we systematically evaluated four biomedical and two non-biomedical grade alginates for their capacity to support the in vitro culture and in vivo transplantation of articular chondrocytes. Chondrocytes in all ultrapure alginates maintained a high cell viability. Spheres composed of biomedical grade, low viscosity, high mannuronic acid content alginate showed the lowest decrease in size over time. Biomedical grade, low viscosity, high guluronic acid content alginate allowed for optimal cell proliferation. Biomedical grade, medium viscosity, high mannuronic acid content alginate promoted the highest production of proteoglycans. When transplanted into articular cartilage defects in the knee joint of sheep in vivo, empty spheres were progressively surrounded by a granulation tissue. In marked contrast with these observations, all alginate spheres carrying allogeneic chondrocytes were gradually invaded by a granulation tissue containing multinucleated giant cells, lymphocytes, and fibroblasts, regardless whether they were based on biomedical or non-biomedical grade alginates. After 21 days in vivo, transplanted chondrocytes were either viable or underwent necrosis, while apoptosis played a minor role in their early fate. The individual characteristics of these alginates may be valuable to tailor specific experimental and clinical strategies for cartilage tissue engineering. PMID: 21457098 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Electro-acupuncture promotes differentiation of mesenchymal stem cells, regeneration of nerve fibers and partial functional recovery after spinal cord injury. Exp Toxicol Pathol. 2011 Jan;63(1-2):151-6 Authors: Yan Q, Ruan JW, Ding Y, Li WJ, Li Y, Zeng YS In order to improve the structure and function of acute spinal cord injury, the present study investigated the effect of electro-acupuncture (EA) on the differentiation of mesenchymal stem cells (MSCs) and the regeneration of nerve fibers in transected spinal cord of rats. The differentiation of MSCs into neuron-like cells and neuroglial cells and regeneraton of 5-hydroxytrptamine (HT) nerve fibers in the injured site of spinal cord were assessed after treatment with EA, MSCs transplantation, and EA plus MSCs transplantation. Compared with the control and MSCs groups, the content of endogenous neurotrophin-3 (NT-3) in the injured site and nearby tissues was increased in EA and EA+MSCs group. The differentiation of MSCs into neuronal-like cells and oligodendrocyte-like cells and number of 5-HT positive nerve fibers in the injured site were enhanced in the EA+MSCs group. Basso, Beattie, Bresnahan score of the paralyzed hindlimbs was highest in the EA+MSCs group. The present study demonstrates that electro-acupuncture can promote the differentiation of MSCs and regeneration of nerve fibers in injured spinal cord through induction of endogenous NT-3, and that combination of EA and MSCs transplantation can improve partial function of paralyzed hindlimbs. PMID: 20005688 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mechanical Properties of Tissue-Engineered Vascular Constructs Produced Using Arterial or Venous Cells. Tissue Eng Part A. 2011 Apr 2; Authors: Gauvin R, Guillemette MD, Galbraith T, Bourget JM, Larouche D, Marcoux H, Aubé D, Hayward C, Auger FA, Germain L There is a clinical need for better blood vessel substitutes since current surgical procedures are limited by the availability of suitable autologous vessels and suboptimal behavior of synthetic grafts in small caliber arterial graft (< 5 mm) applications. The aim of the present study was to compare the mechanical properties of arterial and venous tissue-engineered vascular constructs produced by the self-assembly approach using cells extracted from either the artery or vein harvested from the same human umbilical cord. The production of a vascular construct comprised of a media and an adventitia (TEVMA) was achieved by rolling a continuous tissue sheet containing both SMCs and adventitial fibroblasts grown contiguously in the same tissue culture plate. Histology and immunofluorescence staining were used to evaluate the structure and composition of the extracellular matrix (ECM) of the vascular constructs. The mechanical strength was assessed by uniaxial tensile testing, while viscoelastic behavior was evaluated by stepwise stress-relaxation and by cyclic loading hysteresis analysis. Tensile testing showed that the use of arterial cells resulted in stronger and stiffer constructs when compared to those produced using venous cells. Moreover, cyclic loading demonstrated that constructs produced using arterial cells were able to bear higher loads for the same amount of strain when compared to venous constructs. These results indicate that cells isolated from umbilical cord can be used to produce vascular constructs. Arterial constructs possessed superior mechanical properties when compared to venous constructs produced using cells isolated from the same human donor. This study highlights the fact that SMCs and fibroblasts originating from different cell sources can potentially lead to distinct tissue properties when used in tissue engineering applications. PMID: 21457095 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Advance of neurogenic erectile dysfunction therapy by stem cells]. Fa Yi Xue Za Zhi. 2010 Jun;26(3):206-9 Authors: Shen HJ, Zhu GY Neurogenic erectile dysfunction (NED) commonly results from erectile nerve damage. Recent researches have focused on the preclinical study of stem cell-based therapies targeted at repairing and protecting nervi erigentes. In this paper, researches of NESCs, MDSCs, ASCs and MSCs in NED are reviewed. Early studies have demonstrated that stem cells and gene modified stem cells were effective to the therapy of ED, even likely to cure ED. Stem cells are expected to be applied in the clinical therapy of NED. Stem cells as a new therapy technique will bring up a new challenge in forensic clinical medicine. PMID: 20707282 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Wound microenvironment sequesters adipose-derived stem cells in a murine model of reconstructive surgery in the setting of concurrent distant malignancy. Plast Reconstr Surg. 2011 Apr;127(4):1467-77 Authors: Altman AM, Prantl L, Muehlberg FL, Song YH, Seidensticker M, Butler CE, Alt EU : It is unclear whether mesenchymal stem cells that are applied to regenerate wound tissues can migrate to existing tumors and enhance their growth. The authors investigated whether adipose-derived stem cells had any effect on the growth and progression of distant tumors when applied to a skin wound. PMID: 21460655 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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