|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Characterisation of the human nucleus pulposus cell phenotype and evaluation of novel marker gene expression to define adult stem cell differentiation. Arthritis Rheum. 2010 Aug 18; Authors: Minogue BM, Richardson SM, Zeef LA, Freemont AJ, Hoyland JA OBJECTIVE.: Development of stem cell therapies for regeneration of the nucleus pulposus (NP) are hindered by the lack of specific markers to distinguish NP cells from articular chondrocytes (AC cells). This study details, for the first time, gene expression profiling to identify the human NP phenotype and assesses whether the identified markers can distinguish mesenchymal stem cell (MSC) differentiation to a correct NP cell phenotype. METHODS.: Affymetrix Microarrays were conducted on human NP and AC cells and differential expression levels for several positive (NP) and negative (AC) marker genes validated by qRT-PCR. Novel marker gene and protein expression was also assessed in human bone marrow-derived MSCs (BM-MSCs) and adipose-derived MSCs (ASCs) following differentiation in type I collagen gels. RESULTS.: Analysis identified 12 NP positive and 36 negative marker genes differentially expressed >/=20 fold and for a subset (NP positive genes PAX1, FOXF1, HBB, CA12 and OVOS2; AC genes GDF10, CYTL1, IBSP and FBLN1) differential expression was confirmed by qRT-PCR. Differentiated BM-MSCs and ASCs demonstrated significant increases in the novel NP markers PAX1 and FOXF1. ASCs lacked expression of the AC markers IBSP and FBLN1, whereas BM-MSCs lacked expression of the AC marker IBSP but expressed FBLN1. CONCLUSION.: This study has identified the phenotypic profile of human NP cells. Importantly these markers can be used to determine the in vitro differentiation of MSCs to an NP-like rather than an AC-like phenotype. Interestingly, these results suggest that ASCs may be a more appropriate cell type than BM-MSCs for IVD tissue engineering. PMID: 20722018 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Photochemically crosslinked matrices of gelatin and fibrinogen promote rapid cell proliferation. J Tissue Eng Regen Med. 2010 Aug 17; Authors: Sando L, Danon S, Brownlee AG, McCulloch RJ, Ramshaw JA, Elvin CM, Werkmeister JA Here we report the use of a facile photochemical crosslinking method to fabricate stable polymer matrices from unmodified gelatin and fibrinogen. Gels were produced by covalent crosslinking of the proteins in a rapid photo-oxidative process, catalysed by a ruthenium metal complex and irradiation with visible light. For generation of macroporous, spongy matrices, the proteins and crosslinking reagents were mixed with catalase and hydrogen peroxide to achieve a foaming reaction, producing a stable, foamed matrix that was subsequently photo-crosslinked. C2C12 cells were either seeded onto the matrices after photo-curing or embedded in the protein matrix prior to foaming and crosslinking. Cells seeded onto scaffolds post-curing showed high cell viability and rapid proliferation in vitro. For cells embedded in the matrix prior to crosslinking there was some loss of initial viability, but surviving cells were able to proliferate after a period of in vitro cultivation. The matrices were shown to be biocompatible when implanted into nude mice, with evidence of proliferation and differentiation of cells seeded into the scaffolds. The results are promising for further development of tissue-engineering scaffolds based on this ruthenium-catalysed photo-crosslinking method. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20721871 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of cyclic three-dimensional strain on cell proliferation and collagen synthesis of fibroblast-seeded chitosan-hyaluronan hybrid polymer fiber. J Orthop Sci. 2010 Jul;15(4):569-77 Authors: Sawaguchi N, Majima T, Funakoshi T, Shimode K, Harada K, Minami A, Nishimura S BACKGROUND: Tissue engineering techniques using biodegradable three-dimensional (3D) scaffolds with cultured cells offer more potential alternatives for the treatment of severe ligament and tendon injuries. In tissue engineering, one of the crucial roles of 3D scaffolds is to provide a temporary template with the biomechanical characteristics of the native extracellular matrix (ECM) until the regenerated tissue matures. The purpose of the present study was to assess the effect of various cyclic mechanical stresses on cell proliferation and ECM production in a 3D scaffold made from chitosan and hyaluronan for ligament and tendon tissue engineering. METHODS: Three-dimensional scaffolds seeded with rabbit patella tendon fibroblasts were attached to a bioreactor under various conditions: static group, no strain; stretch group, tensile strain; rotational group, rotational strain; combined group, rotational and tensile strain. In the Static group, 3 weeks of stationary culture was performed. In the remaining three groups, a loading regimen of 0.5 Hz for 18 h and then 6 h rest was carried out for 2 weeks after 1 week of static culture. The DNA content was determined to quantify cell proliferation. Real-time reverse transcription polymerase chain reaction analysis was performed to assess the mRNA levels of the ECM products. RESULTS: DNA content of the combined group was significantly higher than that of the static and stretch groups, and that of the rotational group was significant higher than that of the static and stretch groups at 21 days after cultivation. The mRNA level of types I and III collagen and fibromodulin in the combined group was significantly higher than that in the other three groups. The amount of collagen synthesis in the combined group was higher than that in the static group, but the difference was not significant. CONCLUSIONS: Multidimensional cyclic mechanical strain to mimic the physiological condition in vivo has the potential to improve or accelerate tissue regeneration in ligament and tendon tissue engineering using 3D scaffolds in vitro. PMID: 20721727 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide. Open Biomed Eng J. 2010;4:107-12 Authors: Rocha MF, Mansur AA, Martins CP, Barbosa-Stancioli EF, Mansur HS Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level of oxidation (Iox) characterized by Fourier Transformed Infrared Spectroscopy (FTIR). The potential inflammatory response, cell viability and biocompatibility of such oxidized UHMWPE systems were assessed by a novel biological in vitro assay based on the secretion of nitric oxide (NO) by activated murine macrophages with gamma interferon (IFN-gamma) cytokine and lipopolysaccharide (LPS). Furthermore, macrophage morphologies in contact with UHMWPE oxidized surfaces were analyzed by cell spreading-adhesion procedure using scanning electron microscopy (SEM). The results have given significant evidence that the longer the period of accelerated aging of UHMWPE the higher was the macrophage inflammatory equivalent response based on NO secretion analysis. PMID: 20721321 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Growth factor delivery-based tissue engineering: general approaches and a review of recent developments. J R Soc Interface. 2010 Aug 18; Authors: Lee K, Silva EA, Mooney DJ The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine. PMID: 20719768 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The formation of protein concentration gradients mediated by density differences of poly(ethylene glycol) microspheres. Biomaterials. 2010 Aug 16; Authors: Roam JL, Xu H, Nguyen PK, Elbert DL A critical element in the formation of scaffolds for tissue engineering is the introduction of concentration gradients of bioactive molecules. We explored the use of poly(ethylene glycol) (PEG) microspheres fabricated via a thermally induced phase separation to facilitate the creation of gradients in scaffolds. PEG microspheres were produced with different densities (buoyancies) and centrifuged to develop microsphere gradients. We previously found that the time to gelation following phase separation controlled the size of microspheres in the de-swollen state, while crosslink density affected swelling following buffer exchange into PBS. The principle factors used here to control microsphere densities were the temperature at which the PEG solutions were reacted following phase separation in aqueous sodium sulfate solutions and the length of the incubation period above the 'cloud point'. Using different temperatures and incubation times, microspheres were formed that self-assembled into gradients upon centrifugation. The gradients were produced with sharp interfaces or gradual transitions, with up to 5 tiers of different microsphere types. For proof-of-concept, concentration gradients of covalently immobilized proteins were also assembled. PEG microspheres containing heparin were also fabricated. PEG-heparin microspheres were incubated with fluorescently labeled protamine and used to form gradient scaffolds. The ability to form gradients in microspheres may prove to be useful to achieve better control over the kinetics of protein release from scaffolds or to generate gradients of immobilized growth factors. PMID: 20719381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteogenic differentiation of intact human amniotic membrane. Biomaterials. 2010 Aug 16; Authors: Lindenmair A, Wolbank S, Stadler G, Meinl A, Peterbauer-Scherb A, Eibl J, Polin H, Gabriel C, van Griensven M, Redl H Tissue engineering strategies usually require cell isolation and combination with a suitable biomaterial. Human amniotic membrane (AM) represents a natural two-layered sheet comprising cells with proven stem cell characteristics. In our approach, we evaluated the differentiation potential of AM in toto with its sessile stem cells as alternative to conventional approaches requiring cell isolation and combination with biomaterials. For this, AM-biopsies were differentiated in vitro using two osteogenic media compared with control medium (CM) for 28 days. Mineralization and osteocalcin expression was demonstrated by (immuno)histochemistry. Alkaline phosphatase (AP) activity, calcium contents and mRNA expression of RUNX2, AP, osteopontin, osteocalcin, BMP-2 (bone morphogenetic protein), and BMP-4 were quantified and AM viability was evaluated. Under osteogenic conditions, AM-biopsies mineralized successfully and by day 28 the majority of cells expressed osteocalcin. This was confirmed by a significant rise in calcium contents (up to 27.4 +/- 6.8 mg/dl d28), increased AP activity, and induction of RUNX2, AP, BMP-2 and BMP-4 mRNA expression. Relatively high levels of viability were retained, especially in osteogenic media (up to 78.3 +/- 19.0% d14; 62.9 +/- 22.3% d28) compared to CM (42.2 +/- 15.2% d14; 35.1 +/- 8.6% d28). By this strategy, stem cells within human AM can successfully be driven along the osteogenic pathways while residing within their natural environment. PMID: 20719379 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Suspension Culture of Mammalian Cells using Thermo-Sensitive Microcarrier that Allows Cell Detachment without Proteolytic Enzyme Treatment. Cell Transplant. 2010 Aug 18; Authors: Yang HS, Jeon O, Bhang SH, Lee SH, Kim BS Microcarriers are used to expand anchorage-dependent cells in large-scale suspension bioreactors. Proteolytic enzyme treatment is necessary to detach cells cultured on microcarriers for cell harvest or scale-up, but the enzyme treatment damages the cells and extracellular matrices and complicates the culture process. Here, we fabricated thermo-sensitive microcarriers from which cells can be detached by temperature change without proteolytic enzyme treatment. A thermo-sensitive polymer, poly-N-isopropylacrylamide (pNIPAAm) was incorporated on the surface of Cytodex-3(R) microcarriers. pNIPAAm-grafted microcarriers allowed human bone marrow-derived mesenchymal stem cells (hBMMSCs) to adhere, spread, and grow successfully on the microcarriers as non-grafted microcarriers did. By dropping temperature below 32 degrees , more than 82.5% of hBMMSCs were detached from pNIPAAm-grafted microcarriers. The trypsin treatment for cell detachment induced apoptosis and death of some of the detached cells, but cell detachment from pNIPAAm-grafted microcarriers by temperature change significantly reduced the apoptosis and cell death. Taken together, pNIPAAm-grafted microcarriers can significantly reduce cell extracellular matrix damage in the cell detachment process and simplify the cell detachment process by avoiding proteolytic enzyme treatment. pNIPAAm-grafted microcarriers would be valuable to a variety of potential fields demanding a large amount of cells without cell damage, such as cell therapy, tissue engineering, and other biological and clinical applications. PMID: 20719079 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nanofibers and nanoparticles from the insect-capturing adhesive of the Sundew (Drosera) for cell attachment. J Nanobiotechnology. 2010 Aug 18;8(1):20 Authors: Zhang M, Lenaghan SC, Xia L, Dong L, He W, Henson WR, Fan X ABSTRACT: BACKGROUND: The search for naturally occurring nanocomposites with diverse properties for tissue engineering has been a major interest for biomaterial research. In this study, we investigated a nanofiber and nanoparticle based nanocomposite secreted from an insect-capturing plant, the Sundew, for cell attachment. The adhesive nanocomposite has demonstrated high biocompatibility and is ready to be used with minimal preparation. RESULTS: Atomic force microscopy (AFM) conducted on the adhesive from three species of Sundew found that a network of nanofibers and nanoparticles with various sizes existed independent of the coated surface. AFM and light microscopy confirmed that the pattern of nanofibers corresponded to Alcian Blue staining for polysaccharide. Transmission electron microscopy identified a low abundance of nanoparticles in different pattern from AFM observations. In addition, energy-dispersive X-ray spectroscopy revealed the presence of Ca, Mg, and Cl, common components of biological salts. Study of the material properties of the adhesive yielded high viscoelasticity from the liquid adhesive, with reduced elasticity observed in the dried adhesive. The ability of PC12 neuron-like cells to attach and grow on the network of nanofibers created from the dried adhesive demonstrated the potential of this network to be used in tissue engineering, and other biomedical applications. CONCLUSIONS: This discovery demonstrates how a naturally occurring nanofiber and nanoparticle based nanocomposite from the adhesive of Sundew can be used for tissue engineering, and opens the possibility for further examination of natural plant adhesives for biomedical applications. PMID: 20718990 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Spatiotemporal measurement of freezing-induced deformation of engineered tissues. J Biomech Eng. 2010 Mar;132(3):031003 Authors: Teo KY, Dutton JC, Han B In order to cryopreserve functional engineered tissues (ETs), the microstructure of the extracellular matrix (ECM) should be maintained, as well as the cellular viability since the functionality is closely related to the ECM microstructure. Since the post-thaw ECM microstructure is determined by the deformation of ETs during cryopreservation, freezing-induced deformation of ETs was measured with a newly developed quantum dot (QD)-mediated cell image deformetry system using dermal equivalents as a model tissue. The dermal equivalents were constructed by seeding QD-labeled fibroblasts in type I collagen matrices. After 24 h incubation, the ETs were directionally frozen by exposing them to a spatial temperature gradient (from 4 degrees C to -20 degrees C over a distance of 6 mm). While being frozen, the ETs were consecutively imaged, and consecutive pairs of these images were two-dimensionally cross-correlated to determine the local deformation during freezing. The results showed that freezing induced the deformation of ET, and its magnitude varied with both time and location. The maximum local dilatation was 0.006 s(-1) and was always observed at the phase change interface. Due to this local expansion, the unfrozen region in front of the freezing interface experienced compression. This expansion-compression pattern was observed throughout the freezing process. In the unfrozen region, the deformation rate gradually decreased away from the freezing interface. After freezing/thawing, the ET experienced an approximately 28% decrease in thickness and 8% loss in weight. These results indicate that freezing-induced deformation caused the transport of interstitial fluid, and the interstitial fluid was extruded. In summary, the results suggest that complex cell-fluid-matrix interactions occur within ETs during freezing, and these interactions determine the post-thaw ECM microstructure and eventual post-thaw tissue functionality. PMID: 20459191 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [The effect of TNF-alpha on TAZ expression and osteogenic potential of mesenchymal stem cells from myeloma patients] Zhonghua Zhong Liu Za Zhi. 2009 Jan;31(1):5-9 Authors: Li BZ, Shi MX, Li J, Ma J, Chen L, Chen B, Zhao CH OBJECTIVE: To explore the relationship between TNF-alpha, transcriptional co-activator with PDZ-binding motif (TAZ) and bone disease of multiple myeloma. METHODS: The biological characteristics, especially the osteogenic potential of marrow MSCs from myeloma patients and normal subjects were studied. Real-time RT-PCR and Western-blot were employed to detect mRNA and protein expression of TAZ in MSCs. The concentration of TNF-alpha in the marrow plasma was detected using ELISA method. CD138(+) myeloma cells were cocultured with normal MSCs with or without anti-human TNF-alpha monoclonal antibody in the Transwell system. Real-time RT-PCR was employed to detect the mRNA expressions of ALP, Cbfa1 and TAZ in MSCs two weeks later. von Kossa staining was used to detect the mineral deposition. TNF-alpha was added into the culture media of normal marrow MSCs and real-time RT-PCR and Western-blot were employed to detect mRNA and protein expression of TAZ in MSCs one week later. RESULTS: Real-time RT-PCR revealed that the mRNA of osteogenic markers was decreased in comparison with that of normal controls after cultured in the osteogenic medium. von Kossa staining showed weakened mineral deposition in MSCs from multiple myeloma patients compared with that in normal subjects after osteogenic differentiation for two weeks. The mRNA and protein levels of TAZ in the MSCs from myeloma patients were decreased. TNF-alpha concentration in the marrow plasma of myeloma patients was higher than that in the normal controls [(355.4 +/- 49.1) vs. (92.3 +/- 17.2) pg/ml]. CD138(+) myeloma cells inhibited mRNA expressions of ALP, Cbfal1 and TAZ in MSCs, which could be partially reversed by anti-human TNF-alpha monoclonal antibody. CONCLUSION: The osteogenic potential of MSCs from myeloma patients is significantly decreased in comparison with that in normal subjects, which may play an important role in the pathology of myeloma bone disease. TAZ expression inhibited by TNF-alpha may play an important role in this inhibition effect. PMID: 19538860 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Efficacy of periodontal stem cell transplantation in the treatment of advanced periodontitis. Cell Transplant. 2010 Aug 18; Authors: Park JY, Jeon SH, Choung PH Periodontitis is the most common cause for tooth loss in adults and advanced types affect 10% to 15% of adults worldwide. The attempts to save tooth and regenerate the periodontal apparatus including cementum, periodontal ligament and alveolar bone reach to the dental tissue derived stem cell therapy. Although there have been several periodontitis models suggested, the apical involvement of tooth root is especially challenging to be regenerated and dental stem cell therapy for the state has never been investigated. Three kinds of dental tissue derived adult stem cells (aDSCs) were obtained from the extracted immature molars of beagle dogs (n=8), and ex vivo expanded periodontal ligament stem cells (PDLSCs), dental pulp stem cells (DPSCs), and periapical follicular stem cells (PAFSCs) were transplanted into the apical involvement defect. As for the lack of cementum specific markers, anti-human cementum protein 1 (rhCEMP1) antibody was fabricated and the aDSCs and the regenerated tissues were immunostained with anti-CEMP1 antibody. Autologous PDLSCs showed the best regenerating capacity of periodontal ligament, alveolar bone and cementum as well as peripheral nerve and blood vessel which were evaluated by conventional and immune histology, 3D micro CT and clinical index. The rhCEMP1 was expressed strongest in PDLSCs and in the regenerated periodontal ligament space. We suggest here the PDLSCs as the most favorable candidate for the clinical application among the three dental stem cells and can be used for treatment of advanced periodontitis where tooth removal was indicated in the clinical cases. PMID: 20719084 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Locally Administered Adipose-derived Stem Cells Accelerate Wound Healing through Differentiation and Vasculogenesis. Cell Transplant. 2010 Aug 18; Authors: Nie C, Yang D, Xu J, Si Z, Jin X, Zhang J Despite advances in wound closure techniques and devices, there is still a critical need for new methods of enhancing the healing process to achieve optimal outcomes. Recently, stem cell therapy has emerged as a new approach to accelerate wound healing. Adipose-derived stem cells (ASCs) hold great promise for wound healing, which are multipotential stem cells capable of differentiation into various cell lineages and secretion of angiogenic growth factors. The aim of this study was to evaluate the benefit of ASCs on wound healing and then investigate the probable mechanisms. ASCs characterized by flow cytometry were successfully isolated and cultured. An excisional wound healing model in rat was used to determine the effects of locally administered ASCs. The gross and histological results showed that ASCs significantly accelerated wound closure in normal and diabetic rat, including increased epithelialization and granulation tissue deposition. Furthermore, we applied GFP-labeled ASCs on wounds to determine whether ASCs could differentiate along multiple lineages of tissue regeneration in the specific microenvironment. Immunofluorescent analysis indicated that GFP-expressing ASCs were co-stained with pan-cytokeratin and CD31 respectively, indicating spontaneous site-specific differentiation into epithelial and endothelial lineages. These data suggest that ASCs not only contribute to cutaneous regeneration, but also participate in new vessels formation. Moreover, ASCs were found to secret angiogenic cytokines in vitro and in vivo, including VEGF, HGF and FGF2, which increase neovascularization and enhance wound healing in injured tissues. In conclusion, our results demonstrate that ASCs therapy could accelerate wound healing through differentiation and vasculogenesis and might represent a novel therapeutic approach in cutaneous wounds. PMID: 20719083 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Classification and comparison of niche services for developing strategy of medical tourism in Asian countries. Int Surg. 2010 Apr-Jun;95(2):108-16 Authors: Chen HC, Kuo HC, Chung KP, Chang S, Su S, Yang MC Medical tourism is a new trend in medical service. It is booming not only in Asian countries but also in European and South American countries. Worldwide competition of medical service is expected in the future, and niche service will be a "trademark" for the promotion of global medicine. Niche service also functions for market segmentation. Niche services are usually surgical procedures. A study was carried out to compare different strategies for developing medical tourism in Asian countries. The role of a niche service is evaluated in the initiation and further development of medical tourism for individual countries. From this study, a general classification was proposed in terms of treatment procedures. It can be used as a useful guideline for additional studies in medical tourism. Niche service plays the following roles in the development of medical tourism: (1) It attracts attention in the mass media and helps in subsequent promotion of business, (2) it exerts pressure on the hospital, which must improve the quality of health care provided in treating foreign patients, especially the niche services, and (3) it is a tool for setting up the business model. E-Da Hospital is an example for developing medical tourism in Taiwan. A side effect is that niche service brings additional foreign patients, which will contribute to the benefit of the hospital, but this leaves less room for treating domestic patients. A niche service is a means of introduction for entry into the market of medical tourism. How to create a successful story is important for the development of a niche service. When a good reputation has been established, the information provided on the Internet can last for a long time and can spread internationally to form a distinguished mark for further development. Niche services can be classified into 3 categories: (1) Low-risk procedures with large price differences and long stay after retirement; (2) high-risk procedures with less of a price difference, and (3) banned procedures that are not allowed legally in home countries of foreign patients, such as stem cell therapy. In establishing a niche service, a high-quality, nonmedical segment should be integrated as well. PMID: 20718315 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell therapies for recessive dystrophic epidermolysis bullosa. Br J Dermatol. 2010 Aug 12; Authors: Petrova A, Ilic D, McGrath JA Abstract Human epidermis is composed of a stratified squamous epithelium that provides a mechanical barrier against the external environment and which is renewed every 3-4 weeks by resident stem cells in the epidermis. However, in the inherited skin fragility disorder recessive dystrophic epidermolysis bullosa, RDEB, there is recurrent trauma-induced sub-epidermal blistering that disrupts epidermal homeostasis and is likely to deplete the epidermal stem cell pool. This review article discusses the nature of epidermal stem cells and other stem cell populations in the skin, as well as other possible extra-cutaneous sources of stem cells, that might have physiological or therapeutic relevance to cell therapy approaches for RDEB. Strategies to identify, create and use cells with multipotent or pluripotent properties are explored and current clinical experience of stem cell therapy in RDEB is reviewed. There is currently no single optimal therapy for patients with RDEB, but cell therapy technologies are evolving and hold great potential for modifying disease severity and improving quality of life for people living with RDEB. PMID: 20716209 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Red wine antioxidant resveratrol-modified cardiac stem cells regenerate infarcted myocardium. J Cell Mol Med. 2010 Aug 16; Authors: Gurusamy N, Ray D, Lekli I, Das DK Abstract. To study the efficiency of maintaining the reduced tissue environment via pretreatment with natural antioxidant resveratrol in stem cell therapy, we pretreated male Sprague Dawley rats with resveratrol (2.5 mg/kg/day gavaged for 2 weeks). After occlusion of the left anterior descending coronary artery (LAD), adult cardiac stem cells stably expressing EGFP were injected into the border zone of the myocardium. One week after the LAD occlusion, the cardiac reduced environment was confirmed in resveratrol treated rat hearts by the enhanced expression of nuclear factor-E2-related factor-2 (Nrf2) and redox effector factor-1 (Ref-1). In concert, cardiac functional parameters (left ventricular ejection fraction and fractional shortening) were significantly improved. The improvement of cardiac function was accompanied by the enhanced stem cell survival and proliferation as evidenced by the expression of cell proliferation marker Ki67 and differentiation of stem cells towards the regeneration of the myocardium as evidenced by the expression of EGFP twenty-eight days after LAD occlusion in the resveratrol treated hearts. Our results demonstrate that resveratrol maintained a reduced tissue environment by overexpressing Nrf2 and Ref-1 in rats resulting in an enhancement of the cardiac regeneration of the adult cardiac stem cells as evidenced by increased cell survival and differentiation leading to cardiac function. PMID: 20716127 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Uncultured marrow mononuclear cells delivered within fibrin glue hydrogels to porous scaffolds enhance bone regeneration within critical size rat cranial defects. Tissue Eng Part A. 2010 Aug 17; Authors: Kretlow JD, Spicer PP, Jansen J, Vacanti CA, Kasper FK, Mikos AG For bone tissue engineering, the benefits of incorporating mesenchymal stem cells (MSCs) into porous scaffolds are well established. There is, however, little consensus on the effects of or need for MSC handling ex vivo. Culture and expansion of MSCs adds length, cost, and likely increases risk associated with treatment. We evaluated the effect of using uncultured bone marrow mononuclear cells (bmMNCs) encapsulated within fibrin glue hydrogels and seeded into porous scaffolds to regenerate bone over 12 weeks in an 8 mm diameter, critical size rat cranial defect. A full factorial experimental design was used to evaluate bone formation within model poly(L-lactic acid) and corraline hydroxyapatite scaffolds with or without platelet rich plasma (PRP) and bmMNCs. Mechanical push-out testing, microcomputed tomographical (microCT) analyses, and histology were performed. PRP showed no benefit for bone formation. Cell-laden PLLA scaffolds without PRP required significantly greater force to displace from surrounding tissues than control (cell-free) scaffolds, but no differences were observed during push out testing of coral scaffolds. For bone volume formation as analyzed by microCT, significant positive overall effects were observed with bmMNC incorporation. These data suggest that bmMNCs may provide therapeutic advantages in bone tissue engineering applications without the need for culture, expansion, and purification. PMID: 20715884 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Technologies for cardiac valve prostheses] Kyobu Geka. 2009 Jul;62(8 Suppl):692-8 Authors: Nakano K To show the technological development of cardiac valve prostheses, a historical review of both mechanical and biological valve prostheses and a current overview of modern cardiac valve devices are provided. Scince the 1st implantation of Starr-Edwards ball valve in 1960, both mechanical and biological valve prostheses have advanced. The valve design, the material of the leaflet and the hausing of mechanical prostheses have improved. Currently, the majority of the mechanical prostheses are bileaflet tilting disc valves made of pyrolytic carbon, which is antithromboembolic. However, anticoagulation therapy with warfarin is still required. As for the bioprostheses, although the fixation and anti-mineralization methods of the tissues improved, the durability of these valves is still limited. For the material of the current biological valves, the porcine aortic valve or bovine pericardium are used. The tissues are fixed by non-pressure or low-pressure method in glutaraldehyde solution. A stented and non-stented valves are available. Epoch-making events in this field are the implantation of new bioprosthetic valves using tissue engineering methods and the development of the transcatheter valve replacement therapies. PMID: 20715694 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Human breast milk is a rich source of multipotent mesenchymal stem cells. Hum Cell. 2010 May 1;23(2):35-40 Authors: Patki S, Kadam S, Chandra V, Bhonde R Putative stem cells have been isolated from various tissue fluids such as synovial fluid, amniotic fluid, menstrual blood, etc. Recently the presence of nestin positive putative mammary stem cells has been reported in human breast milk. However, it is not clear whether they demonstrate multipotent nature. Since human breast milk is a non-invasive source of mammary stem cells, we were interested in examining the nature of these stem cells. In this pursuit, we could succeed in isolating and expanding a mesenchymal stem cell-like population from human breast milk. These cultured cells were examined by immunofluorescent labeling and found positive for mesenchymal stem cell surface markers CD44, CD29, SCA-1 and negative for CD33, CD34, CD45, CD73 confirming their identity as mesenchymal stem cells. Cytoskeletal protein marker analysis revealed that these cells expressed mesenchymal stem cells markers, namely, nestin, vimentin, smooth muscle actin and also manifests presence of E-Cadherin, an epithelial to mesenchymal transition marker in their early passages. Further we tested the multipotent differentiation potential of these cells and found that they can differentiate into adipogenic, chondrogenic and oesteogenic lineage under the influence of specific differentiation cocktails. This means that these mesenchymal stem cells isolated from human breast milk could potentially be "reprogrammed" to form many types of human tissues. The presence of multipotent stem cells in human milk suggests that breast milk could be an alternative source of stem cells for autologous stem cell therapy although the significance of these cells needs to be determined. PMID: 20712706 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Subtalar joint arthrodesis, ankle arthrodiastasis, and talar dome resurfacing with the use of a collagen-glycosaminoglycan monolayer. Clin Podiatr Med Surg. 2010 Apr;27(2):327-33 Authors: Ramanujam CL, Sagray B, Zgonis T Intraarticular fractures of the calcaneus are a common injury to the hindfoot leading to posttraumatic arthrosis of the subtalar joint. Operative treatment with reduction and internal fixation at the time of initial presentation and once the soft tissue envelope is deemed suitable has become the standard of care for the surgical management of calcaneal fractures. However, numerous complications have been associated with calcaneal fractures, most notably subtalar joint arthrosis and calcaneal malunion. The authors describe a method of a delayed subtalar joint arthrodesis, ankle joint arthrodiastasis, and talar resurfacing with positive results for the management of painful posttraumatic concomitant arthrosis of the subtalar and ankle joints. PMID: 20470961 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Teaching of direct posterior resin composite restorations in UK dental therapy training programmes. Br Dent J. 2010 May 8;208(9):415-21 Authors: Lynch CD, Wilson NH AIM: With the numbers of dental therapists involved in the delivery of dental care within the UK on the increase, and the trend towards the use of direct resin composites (composites) for the restoration of posterior teeth, this study was undertaken to describe the teaching of posterior composites in dental therapy training programmes in the UK. A secondary aim was to identify differences in techniques for posterior composites taught within these dental therapy training programmes. METHODS: In 2008/9, a questionnaire seeking information on the teaching of posterior composites was distributed by email to 13 centres with dental therapy training programmes in the UK. This questionnaire sought information relating to the teaching of direct posterior composites to dental therapy students, including the amounts of preclinical and clinical teaching in respect of deciduous and permanent teeth, numbers of restorations placed, contraindications to placement, and details in respect of operative techniques. RESULTS: Ten completed responses were received (response rate = 77%). In ten programmes, student dental therapists received clinical training in the placement of composite restorations in the occlusal surfaces of premolar and permanent molar teeth, and nine programmes included such training for two and three surface occlusoproximal restorations. The mean proportions of posterior restorations placed clinically by the trainee dental therapists in permanent teeth using dental amalgam and composite were 52% and 46% respectively (range: amalgam = 20-95%; composite = 5-70%). CONCLUSION: With the exception of one programme, the teaching of posterior composites is a well established element of dental therapy training. Some variations were noted in the teaching of clinical techniques between respondent training centres. It is suggested that to ensure harmony in approaches to treatments provided by graduated therapists that training centres look to relevant consensus documents, such as those of the British Association for the Teaching of Conservative Dentistry. The findings of our study are important for the future provision of oral healthcare, given the growing evidence base in favour of minimally invasive dentistry. PMID: 20448613 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Salivary gland regeneration. Front Oral Biol. 2010;14:107-28 Authors: Carpenter GH, Cotroneo E The ability of animal salivary glands to recover from an experimentally-induced atrophic state offers hope that human salivary glands may be regenerated following injury. Examination of the mechanisms of regeneration in animal models has revealed processes which resemble the embryonic formation of salivary glands. Secretory proteins present in regenerated acinar and ductal cells are the same as found in the perinatal salivary glands. The use of microarrays to reveal global gene changes has, in combination with bioinformatic techniques, identified some of the important signalling cascades operating in the early stages of glandular regeneration. The role of stem cells is also considered and would fit in with current ideas of glandular regeneration, however the isolation and subsequent differentiation of stem cells into a normal reflexly secreting gland still requires considerable research. PMID: 20428014 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Tracheal defect repair using a PLGA-collagen hybrid scaffold reinforced by a copolymer stent with bFGF-impregnated gelatin hydrogel. Pediatr Surg Int. 2010 Jun;26(6):575-80 Authors: Tatekawa Y, Kawazoe N, Chen G, Shirasaki Y, Komuro H, Kaneko M PURPOSE: We studied the regenerated cartilage in tracheal defect repair and compared the bio-materials used versus native trachea using basic fibroblast growth factor (bFGF)-impregnated gelatin hydrogel. MATERIALS AND METHODS: A full-thickness anterior defect was created in the cervical trachea of 15 experimental rabbits. The defect was implanted with a hybrid scaffold of poly(lactic-co-glycolic acid) (PLGA) knitted mesh and collagen sponge. The implanted trachea was reinforced with a copolymer stent of polycaprolactone and poly(lactic acid) coarse fiber mesh. A gelatin hydrogel was used for providing a sustained release of bFGF. The reconstructed tracheas were divided into three groups with wrapped materials; without gelatin hydrogel (control group, n = 5), a gelatin hydrogel with saline (gelatin group, n = 5), and a gelatin hydrogel with 100 microg of bFGF (bFGF group, n = 5). One of the five rabbits in each group at 1 month after operation, one at 3 months, and three at 6 months were killed and the engineered tracheas were evaluated histologically. Biomechanical properties were evaluated on samples at 6 months postoperatively. RESULTS: The rigid support in the defect portion was maintained during 6 months postoperatively. The newly regenerated cartilages were recognized between the host cartilage stumps at 3 months postoperatively in the bFGF group, and limited new cartilage growth and epithelialization were observed at 6 months postoperatively. CONCLUSIONS: The experiment shows that using bFGF, better mechanical strength was obtained but with poor cartilage growth. PMID: 20425118 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Combined Technologies for Microfabricating Elastomeric Cardiac Tissue Engineering Scaffolds. Macromol Biosci. 2010 Aug 18; Authors: Guillemette MD, Park H, Hsiao JC, Jain SR, Larson BL, Langer R, Freed LE Polymer scaffolds that direct elongation and orientation of cultured cells can enable tissue engineered muscle to act as a mechanically functional unit. We combined micromolding and microablation technologies to create muscle tissue engineering scaffolds from the biodegradable elastomer poly(glycerol sebacate). These scaffolds exhibited well defined surface patterns and pores and robust elastomeric tensile mechanical properties. Cultured C2C12 muscle cells penetrated the pores to form spatially controlled engineered tissues. Scanning electron and confocal microscopy revealed muscle cell orientation in a preferential direction, parallel to micromolded gratings and long axes of microablated anisotropic pores, with significant individual and interactive effects of gratings and pore design. PMID: 20718054 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | New insights into induction of early-stage neovascularization in an improved tissue-engineered model of psoriasis. J Tissue Eng Regen Med. 2010 Aug 17; Authors: Krajewska E, Lewis C, Staton C, Macgowan A, Macneil S We have previously shown that putrescine induces a psoriatic phenotype in tissue-engineered skin. The initial aim of this study was to further develop this in vitro model by introducing endothelial cells to mimic the increased vascularization found in psoriasis. Human keratinocytes and fibroblasts, which did not express CD34 or CD31 in 2D culture, were added to de-epidermised acellular human dermis and cultured for 4 weeks. For induction of a psoriatic phenotype, putrescine was added during this period. We report that after 4 weeks of culture, and particularly when exposed to putrescine, this model showed expression of vertically organised clusters of CD31 positive cells in the dermis in the absence of any exogenous endothelial cells. Further investigation in 2D cell cultures showed an indirect effect of putrescine on normal keratinocytes causing them to produce soluble factors that increased expression of CD133, CD34 and CD31 in cultured human dermal fibroblasts, previously negative for these antigens. This study reports a new and improved model of psoriasis for in vitro studies and offers a new insight into early stage neovascularization, which is of relevance not only to psoriasis, but to tissue engineering and wound healing in general. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20718049 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Differential bone-forming capacity of osteogenic cells from either embryonic stem cells or bone marrow-derived mesenchymal stem cells. J Tissue Eng Regen Med. 2010 Aug 17; Authors: Both SK, van Apeldoorn AA, Jukes JM, Englund MC, Hyllner J, van Blitterswijk CA, de Boer J For more than a decade, human mesenchymal stem cells (hMSCs) have been used in bone tissue-engineering research. More recently some of the focus in this field has shifted towards the use of embryonic stem cells. While it is well known that hMSCs are able to form bone when implanted subcutaneously in immune-deficient mice, the osteogenic potential of embryonic stem cells has been mainly assessed in vitro. Therefore, we performed a series of studies to compare the in vitro and in vivo osteogenic capacities of human and mouse embryonic stem cells to those of hMSCs. Embryonic and mesenchymal stem cells showed all characteristic signs of osteogenic differentiation in vitro when cultured in osteogenic medium, including the deposition of a mineralized matrix and expression of genes involved in osteogenic differentiation. As such, based on the in vitro results, osteogenic ES cells could not be discriminated from osteogenic hMSCs. Nevertheless, although osteogenic hMSCs formed bone upon implantation, osteogenic cells derived from both human and mouse embryonic stem cells did not form functional bone, indicated by absence of osteocytes, bone marrow and lamellar bone. Although embryonic stem cells show all signs of osteogenic differentiation in vitro, it appears that, in contrast to mesenchymal stem cells, they do not possess the ability to form bone in vivo when a similar culture method and osteogenic differentiation protocol was applied. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20718035 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Temperature effects on type I pepsin-solubilised collagen extraction from silver-line grunt skin and its in vitro fibril self-assembly. J Sci Food Agric. 2010 Aug 17; Authors: Aukkanit N, Garnjanagoonchorn W BACKGROUND: Fish skin is a potential source of collagen. Increasing the extraction temperature increases the yield of collagen. However, it may also result in degradation of the peptide chains, thus damaging the 3D structure of collagen that is vital for its application as a biomaterial. This work investigated the effects of extraction temperature on the yield and characteristics, including fibril self-assembly, of type I pepsin-solubilised fish skin collagen.RESULTS: Pepsin-solubilised collagens were extracted from fresh skin of silver-line grunt at 4, 10, 20 and 28 degrees C for 6 h. Extraction at 10 degrees C gave the highest yield of collagens (439.32 +/- 96.43 mg g(-1) fresh skin, dry basis), which were identified as type I and comprised beta, alpha1 and alpha2 subunits. Extraction at higher temperatures (20 and 28 degrees C) resulted in the formation of low-molecular-weight peptide fragments, thus reducing the yield of the resultant type I collagen. The denaturation temperatures of collagens extracted at 4 and 10 degrees C, as determined by thermal analysis using differential scanning calorimetry, were 39.5 and 37.5 degrees C respectively. In vitro fibril self-assembly of 1 mg mL(-1) collagen solution (pH 6) incubated at 25 degrees C was only observed with collagens extracted at 4 and 10 degrees C. The 10 degrees C collagen not only showed a higher rate of self-assembly, but its matrix also had a larger fibril diameter of 0.50 +/- 0.07 microm (compared with 0.41 +/- 0.07 microm for the 4 degrees C collagen) after 4 h of incubation.CONCLUSION: The results indicated strong effects of extraction temperature on the yield and characteristics of the collagen obtained. Extraction of pepsin-solubilised collagen from silver-line grunt skin at 4-10 degrees C gave a high yield of type I collagen with molecular integrity suitable for tissue-engineering applications. Copyright (c) 2010 Society of Chemical Industry. PMID: 20718032 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Defining conditions for covalent immobilization of angiogenic growth factors onto scaffolds for tissue engineering. J Tissue Eng Regen Med. 2010 Aug 17; Authors: Chiu LL, Weisel RD, Li RK, Radisic M Rapid vascularization of engineered tissues in vitro and in vivo remains one of the key limitations in tissue engineering. We propose that angiogenic growth factors covalently immobilized on scaffolds for tissue engineering can be used to accomplish this goal. The main objectives of this work were: (a) to derive desirable experimental conditions for the covalent immobilization of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1) on porous collagen scaffolds; and (b) to determine whether primary endothelial cells respond to these scaffolds with covalently immobilized angiogenic factors. VEGF and Ang1 were covalently immobilized onto porous collagen scaffolds, using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) chemistry. To improve covalent immobilization conditions: (a) different reaction buffers [phosphate-buffered saline (PBS), distilled water, or 2-(N-morpholino)ethanesulphonic acid (MES)] were used; and (b) step immobilization was compared to bulk immobilization. In step immobilization, growth factors are applied after EDC activation of the scaffold, while in bulk immobilization, reagents are simultaneously applied to the scaffold. PBS as the reaction buffer resulted in higher amounts of VEGF and Ang1 immobilized (ELISA), higher cell proliferation rates (XTT) and increased lactate metabolism compared to water and MES as the reaction buffers. Step immobilization in PBS buffer was also more effective than bulk immobilization. Immobilized growth factors resulted in higher cell proliferation and lactate metabolism compared to soluble growth factors used at comparable concentrations. Tube formation by CD31-positive cells was also observed in collagen scaffolds with immobilized VEGF or Ang1 using H5V and primary rat aortic endothelial cells but not on control scaffolds. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20717888 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of alginate hydrogels under in vivo-like bioreactor conditions for cartilage tissue engineering. J Mater Sci Mater Med. 2010 Aug 18; Authors: Stojkovska J, Bugarski B, Obradovic B Alginate hydrogels in forms of discs and packed beds of microbeads (~800 mum) were tested in a novel bioreactor at 10% strain using two regimes: at a loading rate of 337.5 mum/s and at sequential increments of 50 mum displacement every 30 min. Compressive strength increased with the increase in alginate concentration (1.5 vs. 2% w/w) and the content of guluronic residues (38.5 vs. 67%). Packed beds of microbeads exhibited significantly higher (~1.5-3.4 fold) compression moduli than the respective discs indicating the effects of gel form and entrapped water. Short-term cultivation of microbeads with immobilized bovine calf chondrocytes (1.5% w/w, 33 x 10(6) cells/ml) under biomimetic conditions (dynamic compression: 1 h on/1 h off, 0.42 Hz, 10% strain) resulted in cell proliferation and bed compaction, so that the compression modulus slightly increased. Thus, the novel bioreactor demonstrated advantages in evaluation of biomaterial properties and cell-biomaterial interactions under in vivo-like settings. PMID: 20717710 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regulating a master regulator: Establishing tissue-specific gene expression in skeletal muscle. Epigenetics. 2010 Nov 16;5(8) Authors: Aziz A, Liu QC, Dilworth FJ MyoD is a master regulator of the skeletal muscle gene expression program. ChIP-Seq analysis has recently revealed that MyoD binds to a large number of genomic loci in differentiating myoblasts, yet only activates transcription at a subset of these genes. Here we discuss recent data suggesting that the ability of MyoD to mediate gene expression is regulated through the function of Polycomb and Trithorax Group proteins. Based on studies of the muscle-specific myog gene, we propose a model where the transcriptional activators Mef2d and Six4 mediate recruitment of Trithorax Group proteins Ash2L/MLL2 and UTX to MyoD-bound promoters to overcome the Polycomb-mediated repression of muscle genes. Modulation of the interaction between Ash2L/MLL2 and Mef2d by the p38alpha MAPK signaling pathway in turns provides fine-tuning of the muscle-specific gene expression program. Thus Mef2d, Six4 and p38alpha MAPK function coordinately as regulators of a master regulator to mediate expression of MyoD target genes. PMID: 20716948 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Phase II trial of bevacizumab and erlotinib in patients with recurrent malignant glioma. Neuro Oncol. 2010 Aug 17; Authors: Sathornsumetee S, Desjardins A, Vredenburgh JJ, McLendon RE, Marcello J, Herndon JE, Mathe A, Hamilton M, Rich JN, Norfleet JA, Gururangan S, Friedman HS, Reardon DA Vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) signaling are established contributors to malignant glioma (MG) biology. We, therefore, evaluated bevacizumab, a humanized anti-VEGF monoclonal antibody, in combination with the EGFR tyrosine kinase inhibitor erlotinib, in this phase 2 study for recurrent MG patients (www.ClinicalTrials.gov, NCT00671970). Fifty-seven patients (n = 25, glioblastoma [GBM]; n = 32, anaplastic glioma [AG]) were enrolled. The primary endpoint was 6-month progression-free survival (PFS-6). Overall survival (OS), radiographic response, pharmacokinetics, and correlative biomarkers were the secondary endpoints. Patients were stratified based on the concurrent use of enzyme-inducing antiepileptic drugs (EIAEDs). Bevacizumab (10 mg/kg) was given intravenously every 2 weeks. Erlotinib was orally administered daily at 200 mg/day for patients not on EIAEDs and 500 mg/day for patients on EIAEDs. PFS-6 and median OS were 28% and 42 weeks for GBM patients and 44% and 71 weeks for AG patients, respectively. Twelve (48%) GBM patients and 10 (31%) AG patients achieved a radiographic response. Erlotinib pharmacokinetic exposures were comparable between EIAED and non-EIAED groups. Rash, mucositis, diarrhea, and fatigue were common but mostly grades 1 and 2. Among GBM patients, grade 3 rash, observed in 32%, was associated with survival benefit, whereas elevated hypoxia-inducible factor-2 alpha and VEGF receptor-2 levels were associated with poor survival. Bevacizumab plus erlotinib was adequately tolerated in recurrent MG patients. However, this regimen was associated with similar PFS benefit and radiographic response when compared with other historical bevacizumab-containing regimens. PMID: 20716591 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Current strategies for knee cartilage repair. Int J Clin Pract. 2010 Sep;64(10):1444-52 Authors: Kalson NS, Gikas PD, Briggs TW Defects in knee articular cartilage (AC) can cause pain and disability and present the clinician with an extremely challenging clinical situation. This article describes the most up-to-date surgical techniques that aim to repair and/or regenerate symptomatic focal defects in AC, which include arthroscopic debridement, microfracture bone marrow stimulation and autologous osteochondral allografting, with an emphasis on autologous chondrocyte implantation. In the future, refinement of tissue-engineering approaches promises to further improve outcome for these patients. PMID: 20716151 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Survival and function of mesenchymal stem cells (MSCs) depend on glucose to overcome exposure to long-term, severe and continuous hypoxia. J Cell Mol Med. 2010 Aug 16; Authors: Deschepper M, Oudina K, David B, Myrtil V, Collet C, Bensidhoum M, Logeart-Avramoglou D, Petite H Abstract Use of mesenchymal stem cells (MSCs) has emerged as a potential new treatment for various diseases but has generated marginally successful results. A consistent finding of most studies is massive death of transplanted cells. The present study examined the respective roles of glucose and continuous severe hypoxia on MSC viability and function in pertinent to bone tissue engineering. We hereby demonstrate for the first time that MSC survive exposure to long-term (12 day), severe (pO(2)< 1.5 mmHg) hypoxia provided that glucose is available. To this aim, an in vitro model that mimics the hypoxic environment and cell-driven metabolic changes encountered by grafted sheep cells was established. In this model, the hallmarks of hypoxia (low pO(2), HIF-1alpha expression and anaerobic metabolism) were present. When conditions switched from hypoxic (low pO(2)) to ischemic (low pO(2) and glucose depletion), MSCs exhibited shrinking, decreased cell viability and ATP content due to complete exhaustion of glucose at day 6; these results provided evidence that ischemia led to the observed massive cell death. Moreover, MSCs exposed to severe, continuous hypoxia, but without any glucose shortage, remained viable and maintained both their in vitro proliferative ability after simulation with blood reperfusion at day 12 and their in vivo osteogenic ability. These findings challenge the traditional view according to which severe hypoxia per se is responsible for the massive MSC death observed upon transplantation of these cells and provide evidence that MSC are able to withstand exposure to severe, continuous hypoxia provided that a glucose supply is available. PMID: 20716129 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evolving paradigms for repair of tissues by adult stem/progenitor cells (MSCs). J Cell Mol Med. 2010 Aug 16; Authors: Prockop DJ, Kota DJ, Bazhanov N, Reger RL Abstract In this review we focus on the adult stem/progenitor cells that were initially isolated from bone marrow and first referred to as colony forming units-fibroblastic(see 1), then as marrow stromal cells(2), and subsequently as either mesenchymal stem cells(3) or multipotent mesenchymal stromal cells (MSCs)(4). The current interest in MSCs and similar cells from other tissues is reflected in over 10,000 citations in PubMed as of this writing with 5 to 10 new publications per day. It is also reflected in over 100 registered clinical trials with MSCs or related cells (http//www.clinicaltrials.gov). As a guide to the vast literature, this review will attempt to summarize many of the publications in terms of three paradigms that have directed much of the work (Figure 1): an initial paradigm that the primary role of the cells was to form niches for hematopoietic stem cells (Paradigm I); a second paradigm that the cells repaired tissues by engraftment and differentiation to replace injured cells (Paradigm II); and the more recent paradigm that MSCs engage in cross-talk with injured tissues and thereby generate microenvironments or "quasi-niches" that enhance the repair tissues (Paradigm III). PMID: 20716123 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The regulatory role of c-MYC on HDAC2 and PcG expression in human multipotent stem cells. J Cell Mol Med. 2010 Aug 16; Authors: Bhandari DR, Seo KW, Jung JW, Kim HS, Yang SR, Kang SK, Kang KS Abstract c-MYC is a well known nuclear oncoprotein having multiple functions in cell proliferation, apoptosis and cellular transformation. Chromosomal modification is also important to the differentiation and growth of stem cells. Histone Deacethylase (HDAC) and Polycomb group (PcG) family genes are well known chromosomal modification genes. The aim of this study was to elucidate the role of c-MYC in the expression of chromosomal modification via the HDAC family genes in human mesenchymal stem cells (hMSCs). To achieve this goal, c-MYC expression was modified by gene knock-down and over-expression via lentivirus vector. Using the modified c-MYC expression, our study was focused on cell proliferation, differentiation and cell cycle. Furthermore, the relationship of c-MYC with HDAC2 and PcG genes was also examined. The cell proliferation and differentiation were checked and shown to be dramatically decreased in c-MYC knocked-down human umbilical cord blood-derived MSCs (hUCB-MSCs), whereas they were increased in c-MYC over-expressing cells. Similarly, RT-PCR and Western Blotting results revealed that HDAC2 expression was decreased in c-MYC knocked-down and increased in c-MYC over-expressing hMSCs. Database indicates presence of c-MYC binding motif (CACGTG) in HDAC2 promoter region, which was confirmed by Chromatin immunoprecipitation (ChIP) assay. The influence of c-MYC and HDAC2 on PcG expression was confirmed. This might indicate the regulatory role of c-MYC over HDAC2 and PcG genes. c-MYCs' regulatory role over HDAC2 was also confirmed in human adipose tissue-derived MSCs (hAD-MSCs) and bone-marrow derived MSCs (hBM-MSCs). From this finding, it can be concluded that c-MYC plays a vital role in cell Proliferation & differentiation via chromosomal modification. PMID: 20716118 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
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