|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | 3D ingrowth of bovine articular chondrocytes in biodegradable cryogel scaffolds for cartilage tissue engineering. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Bölgen N, Yang Y, Korkusuz P, Güzel E, El Haj AJ, Pişkin E A feasibility study was undertaken to examine the potential of biodegradable HEMA-lactate-dextran (HEMA-LLA-D)-based cryogels as scaffolds for cartilage tissue engineering. This was a preliminary in vitro study giving essential information on the biocompatibility of cryogels with cartilage cells. HEMA-lactate (HEMA-LLA) and HEMA-LLA-D were synthesized and characterized by different techniques. Cryogel scaffolds with supermacroporous structures were produced by cryogenic treatment of these macromers. Chondrocytes obtained from bovine articular cartilage were seeded onto cylindrical cryogels and cultured. The samples were examined by several microcopical techniques for cell viability and morphological analyses were performed at two culture points. Histological study of the constructs revealed the cells' growth on the surface and within the scaffolds. Confocal microscopical images demonstrated that the majority of live vs. dead cells had been attached to and integrated with the pores of the scaffold. SEM analysis showed round to oval-shaped chondrocytic cells interconnected with each other by communicating junctions. The chondrocytes rapidly proliferated in the cryogels, manifesting that they fully covered the scaffold surface after 9 days and almost filled the spaces in the pores of the scaffold after 15 days of culture. Chondrocytes secreted significant amount of extracellular matrix in the scaffolds and exhibited highly interconnective morphology. Light and transmission electron microscopy revealed groups of active cartilage cells closely apposed to the cryogel. We concluded that cryogel scaffolds could be excellent candidates for cartilage tissue regeneration with their extraordinary properties, including soft, elastic nature, highly open interconnected pore structure and very rapid, controllable swellability. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21192052 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gellan gum-based hydrogels for intervertebral disc tissue-engineering applications. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Silva-Correia J, Oliveira JM, Caridade SG, Oliveira JT, Sousa RA, Mano JF, Reis RL Intervertebral disc (IVD) degeneration is a challenging clinical problem that urgently demands viable nucleus pulposus (NP) implant materials. The best suited biomaterial for NP regeneration has yet to be identified, but it is believed that biodegradable hydrogel-based materials are promising candidates. In this work, we have developed ionic- and photo-crosslinked methacrylated gellan gum (GG-MA) hydrogels to be used in acellular and cellular tissue-engineering strategies for the regeneration of IVDs. The physicochemical properties of the developed hydrogels were investigated by Fourier-transform infrared spectroscopy, (1)H nuclear magnetic resonance and differential scanning calorimetry. The swelling ability and degradation rate of hydrogels were also analysed in phosphate-buffered saline solution at physiological pH for a period of 30 days. Additionally, the morphology and mechanical properties of the hydrogels were assessed under a scanning electron microscope and dynamic compression, respectively. An in vitro study was carried out to screen possible cytotoxicity of the gellan gum-based hydrogels by culturing rat lung fibroblasts (L929 cells) with hydrogel leachables up to 7 days. The results demonstrated that gellan gum was successfully methacrylated. We observed that the produced GG-MA hydrogels possess improved mechanical properties and lower water uptake ability and degradation rate as compared to gellan gum. This work also revealed that GG-MA hydrogels are non-cytotoxic in vitro, thus being promising biomaterials to be used in IVD tissue-engineering strategies. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191907 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microchannel-patterned and heparin micro-contact-printed biodegradable composite membranes for tissue-engineering applications. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Baran ET, Tuzlakoğlu K, Salgado A, Reis RL Microchannel-patterned starch-poly(capro-lactone)/hydydroxyapatite (SPCL-HA) and starch-poly(lactic acid) (SPLA) composite membranes were produced for use as a laminated tissue-engineering scaffold that incorporates both physical and biochemical patterns. For this purpose, SPCL (30% starch) blended with inorganic hydroxyl apatite (50%) and SPLA (50% starch) membranes were made with compressive moulding. Consequently, the microchannel structures (width 102 µm, 174 µm intervals) were developed on the composite membranes by means of micro-patterned metal mould(s) and hydraulic pressing. An elastomer poly(dimetylsiloxane) stamp was used to transfer heparin as a biochemical cue over the microchannel surfaces by micro-contact printing (µCP). Toluidine blue staining of developed capillaries and heparin µCP-coated membranes showed that heparin was transferred predominantly over the microchannel surfaces. Fibroblast cell culture over the microchannel-formed and heparin µCP-modified SPCL-HA and SPLA membranes showed distinct growth patterns. In contrast to the uniform cell layer formed on unmodified microchannels, the cells were bridging across the grooves of heparin-printed microchannels. At extended culture periods, the heparin-printed microchannels were covered with a layer of fibroblast cells without cellular ingrowths inside. This study indicated that the topographical pattern could induce an organization of fibroblasts only with the biochemical cue and the cells' functions can be controlled spatially over the microchannels by using both cues. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191906 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation of differently sized injectable collagen micro-scaffolds. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Geutjes PJ, Faraj KA, Daamen WF, van Kuppevelt TH Collagen scaffolds have been widely used as biomaterials for tissue engineering. In general, application of scaffolds requires surgery. In this study, we describe a new and simple technique to prepare porous micro-scaffolds from type I collagen fibrils which can be injected, thus preventing surgery. The size of the micro-scaffolds could be easily controlled using sieves with varying cut-offs. EDC-NHS crosslinking was essential to stabilize the collagen micro-scaffolds. Micro-scaffolds were highly porous and could be injected through small diameter needles (18-21 gauge). Collagen micro-scaffolds may be used as injectables for the local delivery of effector molecules and/or cells, thus creating specific niches to enhance local tissue regeneration. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191903 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chondrogenic differentiation of human bone marrow mesenchymal stem cells on polyhydroxyalkanoate (PHA) scaffolds coated with PHA granule binding protein PhaP fused with RGD peptide. Biomaterials. 2010 Dec 27; Authors: You M, Peng G, Li J, Ma P, Wang Z, Shu W, Peng S, Chen GQ Hydrophobic polyhydroxyalkanoate (PHA) scaffolds made of a copolyester of 3-hydroxybutyrate-co-hydroxyhexanoate (PHBHHx) were coated with a fusion protein PHA granule binding protein PhaP fused with RGD peptide (PhaP-RGD). Human bone marrow mesenchymal stem cells (hBMSCs) were inoculated on/in the scaffolds for formation of articular cartilages derived from chondrogenic differentiation of hBMSCs for cartilage tissue engineering. PhaP-RGD coating led to more homogeneous spread of cells, better cell adhesion, proliferation and chondrogenic differentiation in the scaffolds compared with those of PhaP coated or uncoated scaffolds immerging in serum minus chondrogenic induction medium. In addition, more extracellular matrices were produced by the differentiated cells over a period of 14 days on/in the PhaP-RGD coated scaffolds evidenced by scanning electron microscopy imaging, enhanced expression of chondrocyte specific genes including SOX-9, aggrecan and type II collagen, suggesting the positive effect of RGD on extracellular matrix production. Furthermore, cartilage-specific extracellular substances sulphated glycosaminoglycans (sGAG) and total collagen content found on/in the PhaP-RGD coated scaffolds were significantly more compared with that produced by the control and PhaP only coated scaffolds. Homogeneously distributed chondrocytes-like cells forming cartilage-like matrices were observed on/in the PhaP-RGD coated scaffolds after 3 weeks. The results suggested that PhaP-RGD coated PHBHHx scaffold promoted chondrogenic differentiation of hBMSCs and could support cartilage tissue engineering. PMID: 21190731 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro biomedical applications of functionalized iron oxide nanoparticles, including those not related to magnetic properties. Contrast Media Mol Imaging. 2010 Dec 29; Authors: Burtea C, Laurent S, Mahieu I, Larbanoix L, Roch A, Port M, Rousseaux O, Ballet S, Murariu O, Toubeau G, Corot C, Vander Elst L, Muller RN Superparamagnetic iron oxide nanoparticles (SPION) are very promising contrast media, especially for molecular imaging, due to their superior NMR efficacy. They even have wider biomedical applications such as in drug and gene delivery, tissue engineering and bioseparation, or as sensitive biological nanosensors. By coupling them to affinity ligands, SPION can bind to drugs, proteins, enzymes, antibodies or nucleotides. For in vitro biomedical applications, the detection of molecular interaction is possible by using a diversity of systems capable of sensing the magnetic properties of these materials. The goal of the present work was to develop and validate various in vitro biomedical applications of ultrasmall superparamagnetic particles of iron oxide (USPIO), including some that are not related to their magnetic properties. USPIO coated with dextran, starch or bisphosphonate exposing carboxylate groups were synthesized and some of them were functionalized by conjugating various biomolecules, such as biotin, streptavidin and apoptosis, or VCAM-1 specific peptides. The in vitro biomedical applications assessed in the present work included: (1) the relaxometric measurement of antibody concentration, cell receptor expression, molecular interaction, and enzymatic activity in aqueous suspensions; (2) MRI visualization of cells and detection of molecular interaction in an ELISA system; (3) ELISA applications of USPIO derivatives; and (4) detection of specific biomolecules by histochemistry. Our results confirm that rapid and simple in vitro detection of a diversity of functionalized SPION with relevance in medicine is possible by the existing NMR techniques and by chemical staining reactions. The protocols can be applied to minimally prepared biological samples (e.g. whole blood, blood plasma or serum, cell suspensions, biopsies, histological preparations, etc.), and often do not need complicated systems of signal amplification. The use of SPION labeled compounds could furthermore contribute to cost reductions in the diagnosis and in patient care. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21190312 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of three-dimensional culture and incubator gas concentration on phenotype and differentiation capability of human mesenchymal stem cells. J Cell Biochem. 2010 Dec 28; Authors: Karlsen TA, Mirtaheri P, Shahdadfar A, Fløisand Y, Brinchmann JE To obtain sufficient numbers of cells for tissue engineering applications, human bone marrow-derived mesenchymal stem cells (hBM-MSC) are commonly cultured as monolayers in incubators containing room air. In this study we investigated whether 3D culture conditions and incubator gas concentrations more similar to those observed in vivo impacted on cell expansion, differentiation capability or phenotype of hBM-MSC. We found that 3D culture alone increased the expression of some molecules involved in osteogenic and adipogenic differentiation. In contrast, 3D culture did not induce chondrogenic differentiation, but enhanced the response to the chondrogenic differentiation medium. Changing the oxygen concentration to 6% and the carbon dioxide concentration to 7.5% did not impact on the results of any of our assays, showing that the hyperoxia of room air is not detrimental to hBM-MSC proliferation, differentiation or phenotype. © 2010 Wiley-Liss, Inc. PMID: 21190196 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In vitro labeling of hydroxyapatite minerals by an engineered protein. Biotechnol Bioeng. 2010 Dec 28; Authors: Yuca E, Karatas AY, Seker UO, Gungormus M, Dinler-Doganay G, Sarikaya M, Tamerler C Biological and biomimetic synthesis of inorganics have been a major focus in hard tissue engineering as well as in green processing of advanced materials. Among the minerals formed by organisms, calcium phosphate mineralization is studied extensively to understand the formation of mineral rich tissues. Herein, we report an engineered fusion protein that not only targets calcium phosphate minerals but also allows monitoring of biomineralization. To produce the bi-functional fusion protein, nucleotide sequence encoding combinatorially selected hydroxyapatite binding heptapeptides (HABP) was genetically linked to the 3' end of the open reading frame of green fluorescence protein (GFPuv) and successfully expressed in Escherichia coli. The fluorescence and binding activities of the bi-functional proteins were characterized by, respectively, using fluorescence microscopy and quartz crystal microbalance spectroscopy. The utility of GFPuv-HABP fusion protein was assessed for both time-wise monitoring of mineralization and the visualization of the mineralized tissues. We used an alkaline phosphatase (AP) based reaction to control phosphate release, thereby mimicking biological processes, to monitor calcium phosphate mineralization. The increase in mineral amount was observed using the fusion protein at different time points. GFPuv-HABP1 was also used for efficient fluorescence labeling of mineralized regions on the extracted human incisors. Our results demonstrate a simple and versatile application of inorganic binding peptides conjugated with bioluminescence proteins as bi-functional bioimaging molecular probes that target mineralization, and which can be employed to a wide range of biomimetic processing and cell free tissue engineering. © 2010 Wiley Periodicals, Inc. PMID: 21190171 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Autologous stem cell therapy maintains vertebral blood flow and contrast diffusion through the endplate in experimental IDD. Spine (Phila Pa 1976). 2010 Dec 29; Authors: Bendtsen M, Bünger CE, Zou X, Foldager C, Jøregensen HS ABSTRACT: Study Design: Experimental, controlled, randomized and paired studyObjective: To evaluate regenerative effect of stem cell therapy on the vertebral endplate and introduce dynamic contrast enhanced MRI (DCE-MRI) as a tool in the investigation of endplate function.Summary of Background Data: The vertebral endplate plays a crucial role in nutritional supply to the intervertebral disc. Estimation of endplate function is an important parameter in future biologic therapy of intervertebral disc degeneration (IDD).Methods: Four level IDD was induced in each of 15 Göttingen minipigs. Percutaneous intradiscal injection of two hydrogels (Zimmer Biologics Inc, Austin, Texas, USA) and one loaded with stem cells was used as single interventions after 12 weeks. Total observation time was 24 weeks.MRI was performed before treatment and sacrifice.Results: 3 animals were excluded due to spondylo-discitis. Stem cell and hydrogel treatment had significantly higher T2 values, relative vertebral blood flow and volume, as well as lower Pfirrmann scores when compared to degenerative controls. No statistical differences were found compared to normal controls.Conclusion: Stem cell and hydrogel therapy is able to partly regenerate IDD and maintain perfusion and permeability of the vertebral endplate and sunchondral bone. DCE-MRI may become an important tool in future investigation of the vertebral endplate. PMID: 21192305 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Prolonged and repeated upright posture promotes bone formation in rat lumbar vertebrae. Spine (Phila Pa 1976). 2010 Dec 29; Authors: Bian Q, Liang QQ, Hou W, Wan C, Li CG, Zhao YJ, Lu S, Shi Q, Wang YJ ABSTRACT: Study Design. Both forelimbs of rats were amputated and these rats were kept in the custom-made cages to keep prolonged and repeated upright posture. Changes of bone were observed in the lumbar vertebrae at 3 different time points after the surgery.Objective. To investigate the effect of prolonged and repeated upright posture on bone formation of rat lumbar vertebrae.Summary of Background Data. Previous studies show long-term and repeated load induces bone formation, but there are no clear evidences to indicate whether or not long-term and repeated assumption of the upright posture could result in bone formation at rat lumbar vertebrae.Methods. The forelimbs of 30 rats were amputated when they were 1 month old. These rats were kept in the custom-made cages and were forced to stand upright on their hind-limbs and tails to obtain water and food. Normal rats of the same ages kept in regular cages were used as control. The rats were sacrificed at 5, 7, and 9 months after the surgery and lumbar vertebrae samples were harvested for micro-CT, histological and immunohistochemical studies. Total RNA isolated from these samples were used for real-time PCR of type I collagen (Col1α2), type X collagen (Col10α1), transforming growth factor β1 (TGF-β1) and its related nuclear transcript factor runt related transcription factor 2 (Runx2), as well as the biomarker of angiogenesis and vascular invasion, which is also a prerequisite for endochondral bone formation: vascular endothelial growth factor (VEGF)Results. Micro-CT and Histological study showed increase trabecular bone density and increased osteoblast quantities of lumbar vertebrae following surgery. Immunostaining revealed increased protein expression of type I collagen, type X collagen, TGF-β and VEGF. Real-time PCR showed upregulated expression of Col1α2, Col10α1, VEGF, TGF-β1 and Runx2 mRNA.Conclusion. Upright posture induces bone acquisition in the rats' lumbar spine, primarily through the mode of the endochondral ossification, which is associated with increased loading, activated VEGF and TGF-β1 signaling. PMID: 21192306 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mitochondrial Function Controls Proliferation and Early Differentiation Potential of Embryonic Stem Cells. Stem Cells. 2010 Dec 29; Authors: Mandal S, Lindgren AG, Srivastava AS, Clark AT, Banerjee U Pluripotent stem cells hold significant promise in regenerative medicine due to their unlimited capacity for self-renewal, and potential to differentiate into any cell type of the body. In the current study, we demonstrate that proper mitochondrial function is essential for proliferation of undifferentiated embryonic stem cells (ESCs). Attenuating mitochondrial function under self-renewing conditions makes these cells more glycolytic-dependent, and is associated with an increase in the mRNA reserves of Nanog, Oct4 and Sox2. In contrast, attenuating mitochondrial function during the first 7 days of differentiation results in normal repression of Oct4, Nanog and Sox2. However differentiation potential is compromised as revealed by abnormal transcription of multiple Hox genes. Furthermore, under differentiating conditions in which mitochondrial function is attenuated, tumorigenic cells continue to persist. Our results, therefore establish the importance of normal mitochondrial function in ESC proliferation, regulating differentiation, and preventing the emergence of tumorigenic cells during the process of differentiation. PMID: 21192071 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Gellan gum-based hydrogels for intervertebral disc tissue-engineering applications. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Silva-Correia J, Oliveira JM, Caridade SG, Oliveira JT, Sousa RA, Mano JF, Reis RL Intervertebral disc (IVD) degeneration is a challenging clinical problem that urgently demands viable nucleus pulposus (NP) implant materials. The best suited biomaterial for NP regeneration has yet to be identified, but it is believed that biodegradable hydrogel-based materials are promising candidates. In this work, we have developed ionic- and photo-crosslinked methacrylated gellan gum (GG-MA) hydrogels to be used in acellular and cellular tissue-engineering strategies for the regeneration of IVDs. The physicochemical properties of the developed hydrogels were investigated by Fourier-transform infrared spectroscopy, (1)H nuclear magnetic resonance and differential scanning calorimetry. The swelling ability and degradation rate of hydrogels were also analysed in phosphate-buffered saline solution at physiological pH for a period of 30 days. Additionally, the morphology and mechanical properties of the hydrogels were assessed under a scanning electron microscope and dynamic compression, respectively. An in vitro study was carried out to screen possible cytotoxicity of the gellan gum-based hydrogels by culturing rat lung fibroblasts (L929 cells) with hydrogel leachables up to 7 days. The results demonstrated that gellan gum was successfully methacrylated. We observed that the produced GG-MA hydrogels possess improved mechanical properties and lower water uptake ability and degradation rate as compared to gellan gum. This work also revealed that GG-MA hydrogels are non-cytotoxic in vitro, thus being promising biomaterials to be used in IVD tissue-engineering strategies. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191907 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microchannel-patterned and heparin micro-contact-printed biodegradable composite membranes for tissue-engineering applications. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Baran ET, Tuzlakoğlu K, Salgado A, Reis RL Microchannel-patterned starch-poly(capro-lactone)/hydydroxyapatite (SPCL-HA) and starch-poly(lactic acid) (SPLA) composite membranes were produced for use as a laminated tissue-engineering scaffold that incorporates both physical and biochemical patterns. For this purpose, SPCL (30% starch) blended with inorganic hydroxyl apatite (50%) and SPLA (50% starch) membranes were made with compressive moulding. Consequently, the microchannel structures (width 102 µm, 174 µm intervals) were developed on the composite membranes by means of micro-patterned metal mould(s) and hydraulic pressing. An elastomer poly(dimetylsiloxane) stamp was used to transfer heparin as a biochemical cue over the microchannel surfaces by micro-contact printing (µCP). Toluidine blue staining of developed capillaries and heparin µCP-coated membranes showed that heparin was transferred predominantly over the microchannel surfaces. Fibroblast cell culture over the microchannel-formed and heparin µCP-modified SPCL-HA and SPLA membranes showed distinct growth patterns. In contrast to the uniform cell layer formed on unmodified microchannels, the cells were bridging across the grooves of heparin-printed microchannels. At extended culture periods, the heparin-printed microchannels were covered with a layer of fibroblast cells without cellular ingrowths inside. This study indicated that the topographical pattern could induce an organization of fibroblasts only with the biochemical cue and the cells' functions can be controlled spatially over the microchannels by using both cues. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191906 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Placenta-derived MSCs are partially immunogenic and less immunomodulatory than bone marrow-derived MSCs. J Tissue Eng Regen Med. 2010 Dec 29; Authors: Fazekasova H, Lechler R, Langford K, Lombardi G Over the past few years, mesenchymal stem cells (MSCs) have become of increasing interest for use in the field of regenerative medicine. To date, bone marrow (BM) has been the main source of MSCs (BM-MSCs) for both experimental and clinical studies. However, the use of MSCs derived from BM can be problematic, due to the low number of MSCs found in bone marrow aspirates and the invasive procedure associated with obtaining them. We aimed to develop a method of obtaining high numbers of purified MSCs from placental tissue with minimal expansion and to characterize their phenotype and function relative to BM-MSCs. We show here that placenta-derived MSCs (PD-MSCs) can be isolated with high numbers from whole placental tissue. However, PD-MSCs isolated from whole tissue were often found to be a mixed population of both maternal and neonatal cells. The immunological properties of PD-MSCs and BM-MSCs were compared. PD-MSCs were found to express lower levels of HLA class I and higher levels of PDL-1 and CD1a, compared to BM-MSCs. HLA-DR became upregulated in PD-MSCs following treatment with IFNγ, whereas BM-MSCs expressed constitutively low levels of HLA-DR. Whilst untreated or IFNγ-treated BM-MSCs were incapable of stimulating T cells, we observed a small T cell proliferation in response to the highest concentration of PD-MSCs when treated with IFNγ. It was noted that BM-MSCs were more immunomodulatory than PD-MSCs in this study. We therefore suggest that BM-MSCs may be better candidates for use in commercial regenerative or transplantation medicine. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21191904 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human adipose-derived stem cells: Potential clinical applications in surgery. Surg Today. 2011 Jan;41(1):18-23 Authors: Utsunomiya T, Shimada M, Imura S, Morine Y, Ikemoto T, Mori H, Hanaoka J, Iwahashi S, Saito Y, Iwaguro H Regenerative medicine is emerging as a rapidly evolving field of research and therapeutics. Stem cells hold great promise for future translational research and clinical applications in many fields. Much research has focused on mesenchymal stem cells isolated from bone marrow in vitro and in vivo; however, bone marrow procurement causes considerable discomfort to the patient and yields a relatively small number of harvested cells. By contrast, adipose tissue represents an abundant and easily accessible source of adult stem cells, termed adipose-derived stem cells (ADSCs), with the ability to equally differentiate along multiple lineage pathways. These stem cells have angiogenic properties, possibly because of their secretion of cytokines. They may also play a role in healing acute and chronic tissue damage. Subsequently, they have a wide range of potential clinical implications. This article reviews the potential preclinical and clinical applications of mesenchymal stem cells, especially ADSCs, in surgery. PMID: 21191687 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Evolution of gene regulation of pluripotency - the case for wiki tracks at genome browsers. Biol Direct. 2010 Dec 29;5(1):67 Authors: Fuellen G, Struckmann S ABSTRACT: BACKGROUND: Experimentally validated data on gene regulation are hard to obtain. In particular, information about transcription factor binding sites in regulatory regions are scattered around in the literature. This impedes their systematic in-context analysis, e.g. the inference of their conservation in evolutionary history. RESULTS: We demonstrate the power of integrative bioinformatics by including curated transcription factor binding site information into the UCSC genome browser, using wiki and custom tracks, which enable easy publication of annotation data. Data integration allows to investigate the evolution of gene regulation of the pluripotency-associated genes Oct4, Sox2 and Nanog. For the first time, experimentally validated transcription factor binding sites in the regulatory regions of all three genes were assembled together based on manual curation of data from 39 publications. Using the UCSC genome browser, these data were then visualized in the context of multi-species conservation based on genomic alignment. We confirm previous hypotheses regarding the evolutionary age of specific regulatory patterns, establishing their "deep homology". We also confirm some other principles of Carroll's "Genetic theory of Morphological Evolution", such as "mosaic pleiotropy", exemplified by the dual role of Sox2 reflected in its regulatory region. CONCLUSIONS: We were able to elucidate some aspects of the evolution of gene regulation for three genes associated with pluripotency. Based on the expected return on investment for the community, we encourage other scientists to contribute experimental data on gene regulation (original work as well as data collected for reviews) to the UCSC system, to enable studies of the evolution of gene regulation on a large scale, and to report their findings. Reviewers: This article was reviewed by Dr. Gustavo Glusman and Dr. Juan Caballero, Institute for Systems Biology, Seattle, USA (nominated by Dr. Doron Lancet, Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel), Dr. Niels Grabe, TIGA Center (BIOQUANT) and Medical Systems Biology Group, Institute of Medical Biometry and Informatics, University Hospital Heidelberg, Germany (nominated by Dr. Mikhail Gelfand, Department of Bioinformatics, Institute of Information Transfer Problems, Russian Academy of Science, Moscow, Russian Federation) and Dr. Franz-Josef Muller, Center for Regenerative Medicine, The Scripps Research Institute, La Jolla, CA, USA and University Hospital for Psychiatry and Psychotherapy (part of ZIP gGmbH), University of Kiel, Germany (nominated by Dr. Trey Ideker, University of California, San Diego, La Jolla CA, United States). PMID: 21190561 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Long-term in vitro expansion of osteoarthritic human articular chondrocytes do not alter genetic stability: a microsatellite instability analysis. J Cell Physiol. 2010 Dec 28; Authors: Neri S, Mariani E, Cattini L, Facchini A In this study we investigated genetic damage acquisition during in vitro culture of human OA chondrocytes to evaluate their safety for use in regenerative medicine clinical applications. In particular, we have addressed the impact of long-term in vitro culture on simple sequence repeat stability, to evaluate the involvement of the Mismatch repair system (MMR) in the accumulation of genetic damage. MMR, the main post-replicative correction pathway, has a fundamental role in maintaining genomic stability and can be monitored by assessing microsatellite instability (MSI). MMR activity has been reported to decrease with age not only in vivo, but also in vitro in relationship to culture passages. OA chondrocytes from seven donors were cultured corresponding to 13-29 population doublings. Aliquots of the cells were collected and analyzed for MSI at five DNA loci (CD4, VWA, FES, TPOX and P53) and for MMR gene expression at each subculture. Genetic stability was confirmed throughout the culture period. MMR genes demonstrated a strong coordination at the transcriptional level among the different components; expression levels were very low, in accordance with the observed genetic stability. The reduced expression of MMR genes might underline no need for increasing DNA repair control in the culture conditions tested, in which no genetic damage was evidenced. These data argue for the safety of chondrocytes for cellular therapies and are encouraging for the potential use of in vitro expanded OA chondrocytes, supporting the extension of autologous cell therapy procedures to degenerative articular diseases. J. Cell. Physiol. © 2010 Wiley-Liss, Inc. PMID: 21190251 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Disease-specific pluripotent stem cells. Korean J Pediatr. 2010 Aug;53(8):786-9 Authors: Kang HC Induced pluripotent stem (iPS) cells are generated by epigenetic reprogramming of somatic cells through the exogenous expression of transcription factors. Recently, the generation of iPS cells from patients with a variety of genetic diseases was found to likely have a major impact on regenerative medicine, because these cells self-renew indefinitely in culture while retaining the capacity to differentiate into any cell type in the body, thereby enabling disease investigation and drug development. This review focuses on the current state of iPS cell technology and discusses the potential applications of these cells for disease modeling; drug discovery; and eventually, cell replacement therapy. PMID: 21189975 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Assisted Reproductive Technologies (ART) with baboons generate live offspring: a nonhuman primate model for ART and reproductive sciences. Reprod Sci. 2010 Oct;17(10):917-30 Authors: Simerly CR, Castro CA, Jacoby E, Grund K, Turpin J, McFarland D, Champagne J, Jimenez JB, Frost P, Bauer C, Hewitson L, Schatten G Human reproduction has benefited significantly by investigating nonhuman primate (NHP) models, especially rhesus macaques. To expand the Old World monkey species available for human reproductive studies, we present protocols in baboons, our closest Old World primate relatives, for assisted reproductive technologies (ART) leading to live born offspring. Baboons complement rhesus by confirming or modifying observations generated in humans often obtained by the study of clinically discarded specimens donated by anonymous infertility patient couples. Here, baboon ART protocols, including oocyte collection, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), preimplantation development to blastocyst stage, and embryo transfer techniques are described. With baboon ART methodologies in place, motility during baboon fertilization was investigated by time-lapse video microscopy (TLVM). The first ART baboons produced by ICSI, a pair of male twins, were delivered naturally at 165 days postgestation. Genetic testing of these twins confirmed their ART parental origins and demonstrated that they are unrelated fraternal twins not identicals. These results have implications for ART outcomes, embryonic stem cell (ESC) derivation, and reproductive sciences. PMID: 20631291 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Scaffold-free cell sheet injection results in bone formation. J Tissue Eng Regen Med. 2010 Jul;4(5):404-11 Authors: Akahane M, Shigematsu H, Tadokoro M, Ueha T, Matsumoto T, Tohma Y, Kido A, Imamura T, Tanaka Y We previously reported a new cell transplantation method in which mesenchymal stem cells (MSCs) were cultured as cell sheets. The cultured MSC sheets showed high alkaline phosphatase (ALP) activities and osteocalcin (OC) contents. In the present study, we transplanted such sheets by injection to assess whether the injectable MSC sheets could form bone tissue at subcutaneous sites. At 4 weeks after the subcutaneous injection, the injected areas showed hard mass formation. Each mass consisted of newly formed bone, as evaluated by radiographic, histological and gene expression analyses as well as three-dimensional computed tomography (3D-CT). Histological analyses revealed extracellular bone matrix together with osteocytes and active osteoblasts. Real-time PCR analyses showed high ALP and OC mRNA expressions. We also injected the cell sheets into dead bone to determine whether the lost osteogenic potential could be rescued, and histological analyses revealed that the injected cell sheets supplied osteogenic potential to the dead bone. The present study clearly indicates that osteogenic MSC sheets can be transplanted via injection through a needle and that bone formation results in the injected areas. Owing to its usage of a needle for fabrication of in vivo bone tissue, this injection method can be applied as a minimally invasive approach for hard tissue reconstruction. PMID: 20084634 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
