|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Investigating the effects of anterior tibial translation on anterior knee force in the porcine model: Is the porcine knee ACL dependent? J Orthop Res. 2010 Dec 23; Authors: Boguszewski DV, Shearn JT, Wagner CT, Butler DL This study sought to determine anterior force in the porcine knee during simulated 6-degree-of-freedom (DOF) motion to establish the role of the anterior cruciate ligament (ACL). Using a 6-DOF robot, a simulated ovine motion was applied to porcine hind limbs while recording the corresponding forces. Since the porcine knee is more lax than the ovine knee, anterior tibial translations were superimposed on the simulated motion in 2 mm increments from 0 mm to 10 mm to find a condition that would load the ACL. Increments through 8 mm increased anterior knee force, while the 10 mm increment decreased the force. Beyond 4 mm, anterior force increases were non-linear and less than the increases at 2 and 4 mm, which may indicate early structural damage. At 4 mm, the average anterior force was 76.9 ± 10.6 N (mean ± SEM; p < 0.025). The ACL was the primary restraint, accounting for 80-125% of anterior force throughout the range of motion. These results demonstrate the ACL dependence of the porcine knee for the simulated motion, suggesting this model as a candidate for studying ACL function. With reproducible testing conditions that challenge the ACL, this model could be used in developing and screening possible reconstruction strategies. © 2010 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 9999:XX-XX, XXXX. PMID: 21184497 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Temperature-dependent higher order structures of the (Pro-Pro-Gly)(10)-modified dendrimer. Biopolymers. 2010 Dec 23; Authors: Suehiro T, Tada T, Waku T, Tanaka N, Hongo C, Yamamoto S, Nakahira A, Kojima C Collagen is the most abundant protein in mammals and is widely used as a biomaterial for tissue engineering and drug delivery. We previously reported that dendrimers and linear polymers, modified with collagen model peptides (Pro-Pro-Gly)(5), form a collagen-like triple-helical structure; however, its triple helicity needs improvement. In this study, a collagen-mimic dendrimer modified with the longer collagen model peptides, (Pro-Pro-Gly)(10), was synthesized and named PPG10-den. Circular dichroism analysis shows that the efficiency of the triple helix formation in PPG10-den was much improved over the original. The X-ray diffraction analysis suggests that the higher order structure was similar to the collagen triple helix. The thermal stability of the triple helix in PPG10-den was higher than in the PPG10 peptide itself and our previous collagen-mimic polymers using (Pro-Pro-Gly)(5). Interestingly, PPG10-den also assembled at low temperatures. Self-assembled structures with spherical and rod-like shapes were observed by transmission electron microscopy. Furthermore, a hydrogel of PPG10-den was successfully prepared which exhibited the sol-gel transition around 45°C. Therefore, the collagen-mimic dendrimer is a potential temperature-dependent biomaterial. © 2010 Wiley Periodicals, Inc. Biopolymers, 2010. PMID: 21184483 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A medical device for prefabrication of large bone grafts in modern medicine. Med Hypotheses. 2010 Dec 21; Authors: Laflamme C, Rouabhia M Translating advances in the laboratory into sound clinical practice presents a series of formidable conceptual and technical challenges. One of them is our inability to maintain large grafts of living cells upon transfer from in vitro conditions into the host in vivo. This is due mainly to diffusion limitations within the grafting material. We embrace the well-known hypothesis of the "Diamond Concept" in bone tissue regeneration, which includes four key factors. Based on the understanding of basic elements of tissue engineering constructs, prefabrication and conditioning techniques and the nano-vascularisation of the scaffold, we furthermore hypothesize that combinations of cells, solid multipolymeric scaffold as the "core element" working as the extracellular matrix (ECM), growth factors and nano-vascularisation setting may eventually generate a large "ready-to-use"in vitro/in vivo graft. We are confident and think that growth factors will help in the construction of a step-by-step organisation of the bone tissue engineering construct (BTEC). A medical device, named in vitro/in vivo Bone Bioreactor Tissue Engineering Construct (IV2B2TEC), is proposed to fulfil the hypothesis. Soon, we hope to test the above hypothesis on a non-union bone defect in an animal model. This novel strategy will likely open new options for reconstructing extended bone defects and facilitate clinical translation of bone tissue engineering. As compared with conventional reconstructive methods, the strategy has four key advantages and might prove to be a novel armamentarium for clinicians in regenerative medicine. PMID: 21183285 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The potential of combinations of drug-loaded nanoparticle systems and adult stem cells for glioma therapy. Biomaterials. 2010 Dec 21; Authors: Roger M, Clavreul A, Venier-Julienne MC, Passirani C, Montero-Menei CN, Menei P The prognosis of patients with malignant glioma remains extremely poor, despite surgery and improvements in radio- and chemo-therapies. Nanotechnologies hold great promise in glioma therapy as they protect the therapeutic agent and allow its sustained release. However, new paradigms permitting tumor-specific targeting and extensive intratumoral distribution must be developed to efficiently deliver nanoparticles. Modifications and functionalizations of nanoparticles have been developed to specifically track tumor cells. However, these nanoparticles have yielded few clinical results due to intra-patient heterogeneity and inter-patient variability. Stem cells with a specific tropism for brain tumors could be used as delivery vehicles for nanoparticles. Indeed, these cells have a natural tendency to migrate and distribute within the tumor mass and they can also incorporate nanoparticles. Stem cell therapy combined with nanotechnology could be a promising tool to efficiently deliver drugs to brain tumors. PMID: 21183214 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Adhesion of laser in situ keratomileusis-like flaps in the cornea: Effects of crosslinking, stromal fibroblasts, and cytokine treatment. J Cataract Refract Surg. 2011 Jan;37(1):166-72 Authors: Mi S, Dooley EP, Albon J, Boulton ME, Meek KM, Kamma-Lorger CS To evaluate 3 approaches, both cellular and acellular, to improve the healing of laser in situ keratomileusis flaps in bovine corneas. PMID: 21183111 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | C/EBPβ Controls Exercise-Induced Cardiac Growth and Protects against Pathological Cardiac Remodeling. Cell. 2010 Dec 23;143(7):1072-83 Authors: Boström P, Mann N, Wu J, Quintero PA, Plovie ER, Panáková D, Gupta RK, Xiao C, Macrae CA, Rosenzweig A, Spiegelman BM The heart has the ability to grow in size in response to exercise, but little is known about the transcriptional mechanisms underlying physiological hypertrophy. Adult cardiomyocytes have also recently been proven to hold the potential for proliferation, a process that could be of great importance for regenerative medicine. Using a unique RT-PCR-based screen against all transcriptional components, we showed that C/EBPβ was downregulated with exercise, whereas the expression of CITED4 was increased. Reduction of C/EBPβ in vitro and in vivo resulted in a phenocopy of endurance exercise with cardiomyocyte hypertrophy and proliferation. This proliferation was mediated, at least in part, by the increased CITED4. Importantly, mice with reduced cardiac C/EBPβ levels displayed substantial resistance to cardiac failure upon pressure overload. These data indicate that C/EBPβ represses cardiomyocyte growth and proliferation in the adult mammalian heart and that reduction in C/EBPβ is a central signal in physiologic hypertrophy and proliferation. PAPERCLIP: PMID: 21183071 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation; characterization and biocompatibility of electrospinning heparin-modified silk fibroin nanofibers. Int J Biol Macromol. 2010 Dec 20; Authors: Wang S, Zhang Y, Wang H, Dong Z In this study, the electrospun silk fibroin nanofibrous scaffolds were modified with heparin by grafting after plasma treatment and blending electrospinning. Morphology, microstructure, chemical composition and grafting efficiency of the heparin-modified silk fibroin nanofibrous scaffolds were characterized to evaluate the effect of modification by means of scanning electron microscopy (SEM), fourier transform infrared spectra (FTIR) and X-ray photoelectron spectrometer (XPS). The results showed that the heparin was successfully introduced to the silk fibroin nanofibrous scaffolds by both the two kinds of modification, and there was a hydrogen bonding between the silk fibroin and heparin. Moreover, the hydrophilicity, O-containing groups and negative charge density of the heparin-modified scaffolds were enhanced. In vitro coagulation time tests showed that the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) of the heparin-modified scaffolds were much higher than those of the pure silk fibroin scaffolds. L929 fibroblasts and EVCs spread and proliferated better on the heparin-modified scaffolds than on the pure silk fibroin scaffolds. Macrophages, neutrophils and lymphocytes were not observed in the heparin-modified scaffolds, which indicated that the modified scaffolds could induce minor inflammation in vivo. The results indicated that the electrospun heparin-modified silk fibroin nanofibrous scaffolds could be considered as ideal candidates for tissue engineering scaffolds. PMID: 21182858 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of chitin-chitosan/nano TiO(2)-composite scaffolds for tissue engineering applications. Int J Biol Macromol. 2010 Dec 20; Authors: Jayakumar R, Ramachandran R, Divyarani VV, Chennazhi KP, Tamura H, Nair SV In this study, we prepared chitin-chitosan/nano TiO(2) composite scaffolds using lyophilization technique for bone tissue engineering. The prepared composite scaffold was characterized using SEM, XRD, FTIR and TGA. In addition, swelling, degradation and biomineralization capability of the composite scaffolds were also evaluated. The developed composite scaffold showed controlled swelling and degradation when compared to the control scaffold. Cytocompatibility of the scaffold was assessed by MTT assay and cell attachment studies using osteoblast-like cells (MG-63), fibroblast cells (L929) and human mesenchymal stem cells (hMSCs). Results indicated no sign of toxicity and cells were found attached to the pore walls within the scaffolds. These results suggested that the developed composite scaffold possess the prerequisites for tissue engineering scaffolds and it can be used for tissue engineering applications. PMID: 21182857 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Crystal structure of the cambialistic superoxide dismutase from Aeropyrum pernix K1 - insights into the enzyme mechanism and stability. FEBS J. 2010 Dec 7; Authors: Nakamura T, Torikai K, Uegaki K, Morita J, Machida K, Suzuki A, Kawata Y Aeropyrum pernix K1, an aerobic hyperthermophilic archaeon, produces a cambialistic superoxide dismutase that is active in the presence of either of Mn or Fe. The crystal structures of the superoxide dismutase from A. pernix in the apo, Mn-bound and Fe-bound forms were determined at resolutions of 1.56, 1.35 and 1.48 Å, respectively. The overall structure consisted of a compact homotetramer. Analytical ultracentrifugation was used to confirm the tetrameric association in solution. In the Mn-bound form, the metal was in trigonal bipyramidal coordination with five ligands: four side chain atoms and a water oxygen. One aspartate and two histidine side chains ligated to the central metal on the equatorial plane. In the Fe-bound form, an additional water molecule was observed between the two histidines on the equatorial plane and the metal was in octahedral coordination with six ligands. The additional water occupied the postulated superoxide binding site. The thermal stability of the enzyme was compared with superoxide dismutase from Thermus thermophilus, a thermophilic bacterium, which contained fewer ion pairs. In aqueous solution, the stabilities of the two enzymes were almost identical but, when the solution contained ethylene glycol or ethanol, the A. pernix enzyme had significantly higher thermal stability than the enzyme from T. thermophilus. This suggests that dominant ion pairs make A. pernix superoxide dismutase tolerant to organic media. Structured digital abstract • MINT-8075688: Superoxide dismutase (uniprotkb:Q9Y8H8) and Superoxide dismutase (uniprotkb:Q9Y8H8) bind (MI:0407) by cosedimentation in solution (MI:0028) • MINT-8075667: Superoxide dismutase (uniprotkb:Q9Y8H8) and Superoxide dismutase (uniprotkb:Q9Y8H8) bind (MI:0407) by x-ray crystallography (MI:0114) • MINT-8075678: Superoxide dismutase (uniprotkb:Q9Y8H8) and Superoxide dismutase (uniprotkb:Q9Y8H8) bind (MI:0407) by molecular sieving (MI:0071). PMID: 21182595 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Non-Viral Gene Delivery to Mesenchymal Stem Cells: Methods, Strategies and Application in Bone Tissue Engineering and Regeneration. Curr Gene Ther. 2010 Dec 24; Authors: Santos JL, Pandita D, Rodrigues J, Pêgo AP, Granja PL, Tomás H Mesenchymal stem cells (MSCs) can be isolated from several tissues in the body, have the ability to self-renewal, show immune suppressive properties and are multipotent, being able to generate various cell types. At present, due to their intrinsic characteristics, MSCs are considered very promising in the area of tissue engineering and regenerative medicine. In this context, genetic modification can be a powerful tool to control the behavior and fate of these cells and be used in the design of new cellular therapies. Viral systems are very effective in the introduction of exogenous genes inside MSCs. However, the risks associated with their use are leading to an increasing search for non-viral approaches to attain the same purpose, even if MSCs have been shown to be more difficult to transfect in this way. In the past few years, progress was made in the development of chemical and physical methods for non-viral gene delivery. Herein, an overview of the application of those methods specifically to MSCs is given and their use in tissue engineering and regenerative medicine therapeutic strategies highlighted using the example of bone tissue. Key issues and future directions in non-viral gene delivery to MSCs are also critically addressed. PMID: 21182464 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Emerging applications of multifunctional elastin-like recombinamers. Nanomedicine (Lond). 2011 Jan;6(1):111-22 Authors: Rodríguez-Cabello JC, Martín L, Girotti A, García-Arévalo C, Arias FJ, Alonso M Elastin-like recombinamers have grown in popularity in the field of protein-inspired biomimetic materials and have found widespread use in biomedical applications. Modern genetic-engineering techniques have allowed the design of multifunctional materials with an extraordinary control over their architecture and physicochemical properties, such as stimuli-responsiveness, monodispersity, biocompatibility or self-assembly, amongst others. Indeed, these materials are playing an increasingly important role in a diverse range of applications, such as drug delivery, tissue engineering and 'smart' systems. Herein, we review some of the most interesting examples of recent advances and progressive applications of elastin-like recombinamers in biomaterial and nano-engineering sciences in recent years. PMID: 21182423 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Magnetic carbon nanotubes: a new tool for shepherding mesenchymal stem cells by magnetic fields. Nanomedicine (Lond). 2011 Jan;6(1):43-54 Authors: Vittorio O, Quaranta P, Raffa V, Funel N, Campani D, Pelliccioni S, Longoni B, Mosca F, Pietrabissa A, Cuschieri A Aims: We investigated the interaction between magnetic carbon nanotubes (CNTs) and mesenchymal stem cells (MSCs), and their ability to guide these intravenously injected cells in living rats by using an external magnetic field. Materials & methods: Multiwalled CNTs were used to treat MSCs derived from rat bone marrow. Cytotoxicity induced by nanotubes was studied using the WST-1 proliferation and Hoechest 33258 apoptosis assays. The effects of nanotubes on MSCs were evaluated by monitoring the effects on cellular growth rates, immunophenotyping and differentiation, and on the arrangement of cytosckeletal actin. MSCs loaded with nanotubes were injected in vivo in the portal vein of rats driving their localization in the liver by magnetic field. An histological analysis was performed on the liver, lungs and kidneys of all animals. Results: CNTs did not affect cell viability and their ability to differentiate in osteocytes and adipocytes. Both the CNTs and the magnetic field did not alter the cell growth rate, phenotype and cytoskeletal conformation. CNTs, when exposed to magnetic fields, are able to shepherd MSCs towards the magnetic source in vitro. Moreover, the application of a magnetic field alters the biodistribution of CNT-labelled MSCs after intravenous injection into rats, increasing the accumulation of cells into the target organ (liver). Conclusion: Multiwalled CNTs hold the potential for use as nanodevices to improve therapeutic protocols for transplantation and homing of stem cells in vivo. This could pave the way for the development of new strategies for the manipulation/guidance of MSCs in regenerative medicine and cell transplantation. PMID: 21182417 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Nonperturbative Chemical Modification of Graphene for Protein Micropatterning. Langmuir. 2010 Dec 23; Authors: Kodali VK, Scrimgeour J, Kim S, Hankinson JH, Carroll KM, de Heer WA, Berger C, Curtis JE Graphene's extraordinary physical properties and its planar geometry make it an ideal candidate for a wide array of applications, many of which require controlled chemical modification and the spatial organization of molecules on its surface. In particular, the ability to functionalize and micropattern graphene with proteins is relevant to bioscience applications such as biomolecular sensors, single-cell sensors, and tissue engineering. We report a general strategy for the noncovalent chemical modification of epitaxial graphene for protein immobilization and micropatterning. We show that bifunctional molecule pyrenebutanoic acid-succinimidyl ester (PYR-NHS), composed of the hydrophobic pyrene and the reactive succinimide ester group, binds to graphene noncovalently but irreversibly. We investigate whether the chemical treatment perturbs the electronic band structure of graphene using X-ray photoemission (XPS) and Raman spectroscopy. Our results show that the sp(2) hybridization remains intact and that the π band maintains its characteristic Lorentzian shape in the Raman spectra. The modified graphene surfaces, which bind specifically to amines in proteins, are micropatterned with arrays of fluorescently labeled proteins that are relevant to glucose sensors (glucose oxidase) and cell sensor and tissue engineering applications (laminin). PMID: 21182241 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Engineered Cartilage Covered Ear Implants for Auricular Cartilage Reconstruction. Biomacromolecules. 2010 Dec 23; Authors: Lee SJ, Broda C, Atala A, Yoo JJ Cartilage tissues are often required for auricular tissue reconstruction. Currently, alloplastic ear-shaped medical implants composed of silicon and polyethylene are being used clinically. However, the use of these implants is often associated with complications, including inflammation, infection, erosion, and dislodgement. To overcome these limitations, we propose a system in which tissue-engineered cartilage serves as a shell that entirely covers the alloplastic implants. This study investigated whether cartilage tissue, engineered with chondrocytes and a fibrin hydrogel, would provide adequate coverage of a commercially used medical implant. To demonstrate the in vivo stability of cell-fibrin constructs, we tested variations of fibrinogen and thrombin concentration as well as cell density. After implantation, the retrieved engineered cartilage tissue was evaluated by histo- and immunohistochemical, biochemical, and mechanical analyses. Histomorphological evaluations consistently showed cartilage formation over the medical implants with the maintenance of dimensional stability. An initial cell density was determined that is critical for the production of matrix components such as glycosaminoglycans (GAG), elastin, type II collagen, and for mechanical strength. This study shows that engineered cartilage tissues are able to serve as a shell that entirely covers the medical implant, which may minimize the morbidity associated with implant dislodgement. PMID: 21182236 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Co-Electrospun Blends of PLGA, Gelatin, and Elastin as Potential Nonthrombogenic Scaffolds for Vascular Tissue Engineering. Biomacromolecules. 2010 Dec 23; Authors: Han J, Lazarovici P, Pomerantz C, Chen X, Wei Y, Lelkes PI In search for novel biomimetic scaffolds for application in vascular tissue engineering, we evaluated a series of fibrous scaffolds prepared by coelectrospinning tertiary blends of poly(lactide-co-glycolide) (PLGA), gelatin, and elastin (PGE). By systematically varying the ratios of PLGA and gelatin, we could fine-tune fiber size and swelling upon hydration as well as the mechanical properties of the scaffolds. Of all PGE blends tested, PGE321 (PLGA, gelatin, elastin v/v/v ratios of 3:2:1) produced the smallest fiber size (317 ± 46 nm, 446 ± 69 nm once hydrated) and exhibited the highest Young's modulus (770 ± 131 kPa) and tensile strength (130 ± 7 kPa). All PGE scaffolds supported the attachment and metabolization of human endothelial cells (ECs) and bovine aortic smooth muscle cells (SMCs) with some variances in EC morphology and cytoskeletal spreading observed at 48 h postseeding, whereas no morphologic differences were observed at confluence (day 8). The rate of metabolization of ECs, but not of SMCs, was lower than that on tissue culture plastic and depended on the specific PGE composition. Importantly, PGE scaffolds were capable of guiding the organotypic distribution of ECs and SMCs on and within the scaffolds, respectively. Moreover, the EC monolayer generated on the PGE scaffold surface was nonthrombogenic and functional, as assessed by the basal and cytokine-inducible levels of mRNA expression and amidolytic activity of tissue factor, a key player in the extrinsic clotting cascade. Taken together, our data indicate the potential application of PGE scaffolds in vascular tissue engineering. PMID: 21182235 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effects of low frequency electromagnetic fields on the chondrogenic differentiation of human mesenchymal stem cells. Bioelectromagnetics. 2010 Dec 22; Authors: Mayer-Wagner S, Passberger A, Sievers B, Aigner J, Summer B, Schiergens TS, Jansson V, Müller PE Electromagnetic fields (EMF) have been shown to exert beneficial effects on cartilage tissue. Nowadays, differentiated human mesenchymal stem cells (hMSCs) are discussed as an alternative approach for cartilage repair. Therefore, the aim of this study was to examine the impact of EMF on hMSCs during chondrogenic differentiation. HMSCs at cell passages five and six were differentiated in pellet cultures in vitro under the addition of human fibroblast growth factor 2 (FGF-2) and human transforming growth factor-β(3) (TGF-β(3)). Cultures were exposed to homogeneous sinusoidal extremely low-frequency magnetic fields (5 mT) produced by a solenoid or were kept in a control system. After 3 weeks of culture, chondrogenesis was assessed by toluidine blue and safranin-O staining, immunohistochemistry, quantitative real-time polymerase chain reaction (PCR) for cartilage-specific proteins, and a DMMB dye-binding assay for glycosaminoglycans. Under EMF, hMSCs showed a significant increase in collagen type II expression at passage 6. Aggrecan and SOX9 expression did not change significantly after EMF exposure. Collagen type X expression decreased under electromagnetic stimulation. Pellet cultures at passage 5 that had been treated with EMF provided a higher glycosaminoglycan (GAG)/DNA content than cultures that had not been exposed to EMF. Chondrogenic differentiation of hMSCs may be improved by EMF regarding collagen type II expression and GAG content of cultures. EMF might be a way to stimulate and maintain chondrogenesis of hMSCs and, therefore, provide a new step in regenerative medicine regarding tissue engineering of cartilage. Bioelectromagnetics. © 2010 Wiley-Liss, Inc. PMID: 21181904 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells from development to postnatal joint homeostasis, aging, and disease. Birth Defects Res C Embryo Today. 2010 Dec;90(4):257-71 Authors: De Bari C, Kurth TB, Augello A Joint morphogenesis involves signaling pathways and growth factors that recur in the adult life with less redundancy to safeguard joint homeostasis. Loss of such homeostasis due to abnormal signaling networks as in aging could lead to diseases such as osteoarthritis. Stem cells are the cellular counterpart and targets of the morphogenetic signals, and they function to maintain the tissues by ensuring replacement of cells lost to physiological turnover, injury, aging, and disease. Mesenchymal stem cells (MSCs) are key players in regenerative medicine for their ability to differentiate toward multiple lineages such as cartilage and bone, but they age along the host body and senesce when serially passaged in culture. Understanding correlations between aging and its effects on MSCs is of the utmost importance to explain how aging happens and unravel the underlying mechanisms. The investigation of the MSC senescence in culture will help in developing more efficient and standardized cell culture methods for cellular therapies in skeletal regenerative medicine. An important area to explore in biomedical sciences is the role of endogenous stem cell niches in joint homeostasis, remodeling, and disease. It is anticipated that an understanding of the stem cell niches and related remodeling signals will allow the development of pharmacological interventions to support effective joint tissue regeneration, to restore joint homeostasis, and to prevent osteoarthritis. Birth Defects Research (Part C) 90:257-271, 2010. © 2010 Wiley-Liss, Inc. PMID: 21181887 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Electrospun PLGA-silk fibroin-collagen nanofibrous scaffolds for nerve tissue engineering. In Vitro Cell Dev Biol Anim. 2010 Dec 22; Authors: Wang G, Hu X, Lin W, Dong C, Wu H Electrospun nanofibrous scaffolds varying different materials are fabricated for tissue engineering. PLGA, silk fibroin, and collagen-derived scaffolds have been proved on good biocompatibility with neurons. However, no systematic studies have been performed to examine the PLGA-silk fibroin-collagen (PLGA-SF-COL) biocomposite fiber matrices for nerve tissue engineering. In this study, different weight ratio PLGA-SF-COL (50:25:25, 30:35:35) scaffolds were produced via electrospinning. The physical and mechanical properties were tested. The average fiber diameter ranged from 280 + 26 to 168 + 21 nm with high porosity and hydrophilicity; the tensile strength was 1.76 ± 0.32 and 1.25 ± 0.20 Mpa, respectively. The results demonstrated that electrospinning polymer blending is a simple and effective approach for fabricating novel biocomposite nanofibrous scaffolds. The properties of the scaffolds can be strongly influenced by the concentration of collagen and silk fibroin in the biocomposite. To assay the cytocompatibility, Schwann cells were seeded on the scaffolds; cell attachment, growth morphology, and proliferation were studied. SEM and MTT results confirmed that PLGA-SF-COL scaffolds particularly the one that contains 50% PLGA, 25% silk fibroin, and 25% collagen is more suitable for nerve tissue engineering compared to PLGA nanofibrous scaffolds. PMID: 21181450 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Differentiation character of adult mesenchymal stem cells and transfection of MSCs with lentiviral vectors. J Huazhong Univ Sci Technolog Med Sci. 2010 Dec;30(6):687-693 Authors: Zhang X, Li J, Nie J, Jiang K, Zhen Z, Wang J, Shen L This study examined the differentiation character and pluripotency of mesenchymal stem cells (MSCs) under different conditions. Adult MSCs were initially isolated from the bone marrow of rats, cultured in vitro and identified by flow cytometry. After MSCs were transferred to osteogenic and adipogenic medium respectively, the morphological characterization of induced cells was observed. The expression of marker genes was detected by RT-PCR analysis. Then MSCs were transfected with lentiviral vectors pGC-FU-Sox9-EGFP. Enhanced green fluorescence protein (EGFP) expression and transfection efficiency were determined by fluorescence microscopy. The results demonstrated that EGFP caused no effect on the multilineage potential of adult MSCs. Sox9 gene expression of high level was maintained stable in the transfected MSCs and induced MSCs to differentiate into chondrocytes. Aggracan was positive in chondrogenic lineages and the expression of aggracan and type collagen II was significantly increased during MSCs chondrogenic differentiation. It was concluded that Sox9 gene-modified adult MSCs may be promising candidate cells for further studies on tissue engineering. EGFP facilitates the research on MSCs physiological behavior and application in tissue engineering during differentiation both in vitro and in vivo. PMID: 21181355 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Icariin induces mouse embryonic stem cell differentiation into beating functional cardiomyocytes. Mol Cell Biochem. 2010 Dec 23; Authors: Sun X, Sun X, Jin X, Zhang X, Liu C, Lei L, Jin L, Liu H Icariin, the primary active component of Epimedium extracts, has recently been shown to induce cardiomyocyte differentiation of murine embryonic stem (mES) cells in vitro. However, as these cardiomyocytes were not functionally characterized, the potential application of icariin-induced cardiomyocytes in clinical practice remains unclear. Therefore, in this study, we characterized the structure and function of icariin-induced cardiomyocytes to evaluate their potential application in transplantation for cardiac failure treatment. mES cells were cultured as embryoid bodies (EBs) via the direct suspension method in the presence of icariin. The protein expression profiles and ultrastructural characteristics of mES cell-derived cardiomyocytes were then characterized by immunofluorescence and transmission electron microscopy, respectively. In addition, the expression of cardiac-specific and calcium handling genes was detected by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). Cardiomyocytes induced by icariin treatment expressed the cardiac-specific proteins myosin light chain-1v (MLC1v), atrial natriuretic polypeptide (ANP), and cardiac troponin I (cTnI). Furthermore, these cells appeared to possess myofibrils organized into mature sarcomeres that had formed A and I bands. In addition, icariin treatment upregulated the mRNA levels of MLC1v, ANP, cTnI, calsequestrin (CSQ), and sodium-calcium exchanger (NCX) in these cells. Icariin induces the differentiation of mES cells into beating cardiomyocytes with normal structure and function. Therefore, these cells may have promising applications in cardiac cell therapy or tissue engineering. PMID: 21181238 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Study on osteogenic ability of chitosan/beta-tricalcium phosphate scaffold combined with human bone morphogenetic protein]. Hua Xi Kou Qiang Yi Xue Za Zhi. 2010 Oct;28(5):464-7 Authors: Lai RF, Zhao QT, Liu XN, Shen S Using chitosan (CS)/beta-tricalcium phosphate (TCP)/recombinant human bone morphogenetic protein (rhBMP)-2 for the reconstruction of rabbits' mandible defect, to prove the feasibility of CS/beta-TCP as an injectable bone tissue engineering scaffold material. PMID: 21179674 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | 'Young' oral fibroblasts are geno/phenotypically distinct. J Dent Res. 2010 Dec;89(12):1407-13 Authors: Enoch S, Peake MA, Wall I, Davies L, Farrier J, Giles P, Kipling D, Price P, Moseley R, Thomas D, Stephens P Wound healing within the oral mucosa results in minimal scar formation compared with wounds within the skin. We have recently demonstrated distinct differences in the aging profiles of cells (oral mucosal and patient-matched skin fibroblasts) isolated from these tissues. We hypothesized that the increased replicative potential of oral mucosal fibroblasts may confer upon them preferential wound-healing capacities. Passage-matched early cultures of oral mucosal fibroblasts and skin fibroblasts demonstrated distinct gene expression profiles, with several genes linked to wound healing/tissue repair. This was related to an increased ability of the 'replicatively younger' oral mucosal fibroblasts to repopulate a wound space and reorganize their surrounding extracellular matrix environment, key activities during the wound-healing process. We conclude that oral mucosal fibroblasts exhibit a preferential healing response in vivo, due to their 'replicatively younger' phenotype when compared with that of patient-matched skin fibroblasts. PMID: 21098492 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Biomechanical evaluation of acellular collagen matrix augmented Achilles tendon repair in sheep. J Foot Ankle Surg. 2010 Sep-Oct;49(5):438-41 Authors: Song L, Olsen RE, Spalazzi JP, Davisson T The rate of rerupture of repaired Achilles tendon in young and athletic populations remains high despite improvement in surgical techniques, suture design, and postsurgical management. Acellular biological matrices can be used to enhance the immediate strength of repaired tendons and to serve as scaffolds for cell in-growth and constructive tissue remodeling. A number of commercially available matrices have been used clinically, albeit with varying degrees of success and failure. The disparity is likely attributable to the different physical and biochemical properties of individual matrices. In this study, we investigated the biomechanical characteristics of 2 different acellular collagen matrices, namely TissueMend and GraftJacket, using a sheep Achilles tendon repair model. Static and cyclic creep, cyclic and linear construct stiffness, maximum load to failure, and displacement at maximum load were determined at time zero. We found that the maximum load to failure, displacement, and ultimate failure mode were similar between tendons augmented with either acellular collagen matrix; however, TissueMend augmentation yielded lower creep and smaller construct elongation than did GraftJacket. The results indicated that the strength of TissueMend-augmented tendons and GraftJacket-augmented tendons was not statistically significantly different, although tendons augmented with TissueMend displayed greater stiffness, which may be clinically advantageous in the restoration of ruptured tendons. PMID: 20797586 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Expression and secretion of interleukin-1β, tumour necrosis factor-α and interleukin-10 by hypoxia- and serum-deprivation-stimulated mesenchymal stem cells. FEBS J. 2010 Sep;277(18):3688-98 Authors: Li Z, Wei H, Deng L, Cong X, Chen X To understand the potential paracrine roles of interleukin-1β (IL-1β), tumour necrosis factor-α (TNF-α) and interleukin-10 (IL-10), the expression and secretion of these factors by rat bone marrow-derived mesenchymal cells stimulated by hypoxia (4% oxygen) and serum deprivation (hypoxia/SD) were investigated. We found that hypoxia/SD induced nuclear factor kappa Bp65-dependent IL-1β and TNF-α transcription. Furthermore, hypoxia/SD stimulated the translation of pro-IL-1β and its processing to mature IL-1β, although the translation of TNF-α was unchanged. Unexpectedly, the release of IL-1β and TNF-α from hypoxia/SD-stimulated mesenchymal cells was undetectable unless ATP or lipopolysaccharide was present. This result suggests that IL-1β and TNF-α are not responsible for the paracrine effects of mesenchymal cells under ischaemic conditions. We also found that hypoxia/SD induced the transcription and secretion of IL-10, which were significantly enhanced by lipopolysaccharide and the proteasomal inhibitor MG132. Moreover, both the conditioned medium from hypoxia/SD-stimulated mesenchymal cells (MSC-CM) and IL-10 efficiently inhibited cardiac fibroblast proliferation and collagen expression in vitro, suggesting that mesenchymal cell-secreted IL-10 prevents cardiac fibrosis in a paracrine manner under ischaemic conditions. Taken together, these findings may improve understanding of the cellular and molecular basis of the anti-inflammatory and paracrine effects of mesenchymal cells. PMID: 20681988 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A novel vascularized patch enhances cell survival and modifies ventricular remodeling in a rat myocardial infarction model. J Thorac Cardiovasc Surg. 2010 Dec;140(6):1388-96.e1-3 Authors: Zhou Q, Zhou JY, Zheng Z, Zhang H, Hu SS Although stem cells hold a great therapeutic potential for injured tissues, limited survival of transplanted stem cells has hindered the clinical application of this technology. We hypothesized that an omentum-based stem cell-supporting patch could provide adequate nutrients and microenvironment to prolong cell survival. We examined this hypothesis in rats with experimental myocardial infarction. PMID: 20619860 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Apical conicity ratio: a new index on left ventricular apical geometry after myocardial infarction. J Thorac Cardiovasc Surg. 2010 Dec;140(6):1402-7.e1-3 Authors: Fan H, Zheng Z, Feng W, Zhang Y, Jin L, Li P, Hu S Our objective was to introduce a new index to evaluate left ventricular aneurysm by quantitative analysis of left ventricular apical geometry. PMID: 20381083 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Focal injection of vancomycin combined with surgical debridement-dermatoplasty in the treatment of pseudo-epitheliomatous granuloma. Burns. 2010 Jun;36(4):552-7 Authors: Jiang DY, Fu XB, Zong XL, Chen B, Wang JC, Shan F Pseudo-epitheliomatous granuloma (PEG) can occur in some small skin wounds with secondary infections resulting from improper treatments. It is difficult to heal and can easily relapse. PMID: 19767150 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [In vivo magnetic resonance imaging tracking of transplanted adipose-derived stem cells labeled with superparamagnetic iron oxide in rat hearts]. Zhongguo Yi Xue Ke Xue Yuan Xue Bao. 2009 Apr;31(2):187-91 Authors: Liu ZY, Wang Y, Wang GY, Li XH, Li Y, Liang CH To investigate the feasibility of in vivo magnetic resonance imaging (MRI) tracking of transplanted adipose-derived stem cells (ADSCs) labeled with superparamagnetic iron oxide (SPIO) in rat heart. PMID: 19507598 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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