|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | 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] | | | | | | | | | | | | | | | | | | | | | | | | | [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] | | | | | | | | | | | | | | | | | | | | | | | | | Applications of patient-specific induced pluripotent stem cells; focused on disease modeling, drug screening and therapeutic potentials for liver disease. Int J Biol Sci. 2010;6(7):796-805 Authors: Chun YS, Chaudhari P, Jang YY The recent advances in the induced pluripotent stem cell (iPSC) research have significantly changed our perspectives on regenerative medicine by providing researchers with a unique tool to derive disease-specific stem cells for study. In this review, we describe the human iPSC generation from developmentally diverse origins (i.e. endoderm-, mesoderm-, and ectoderm- tissue derived human iPSCs) and multistage hepatic differentiation protocols, and discuss both basic and clinical applications of these cells including disease modeling, drug toxicity screening/drug discovery, gene therapy and cell replacement therapy. PMID: 21179587 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | A second-generation device for automated training and quantitative behavior analyses of molecularly-tractable model organisms. PLoS One. 2010;5(12):e14370 Authors: Blackiston D, Shomrat T, Nicolas CL, Granata C, Levin M A deep understanding of cognitive processes requires functional, quantitative analyses of the steps leading from genetics and the development of nervous system structure to behavior. Molecularly-tractable model systems such as Xenopus laevis and planaria offer an unprecedented opportunity to dissect the mechanisms determining the complex structure of the brain and CNS. A standardized platform that facilitated quantitative analysis of behavior would make a significant impact on evolutionary ethology, neuropharmacology, and cognitive science. While some animal tracking systems exist, the available systems do not allow automated training (feedback to individual subjects in real time, which is necessary for operant conditioning assays). The lack of standardization in the field, and the numerous technical challenges that face the development of a versatile system with the necessary capabilities, comprise a significant barrier keeping molecular developmental biology labs from integrating behavior analysis endpoints into their pharmacological and genetic perturbations. Here we report the development of a second-generation system that is a highly flexible, powerful machine vision and environmental control platform. In order to enable multidisciplinary studies aimed at understanding the roles of genes in brain function and behavior, and aid other laboratories that do not have the facilities to undergo complex engineering development, we describe the device and the problems that it overcomes. We also present sample data using frog tadpoles and flatworms to illustrate its use. Having solved significant engineering challenges in its construction, the resulting design is a relatively inexpensive instrument of wide relevance for several fields, and will accelerate interdisciplinary discovery in pharmacology, neurobiology, regenerative medicine, and cognitive science. PMID: 21179424 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Differential genomic targeting of the transcription factor TAL1 in alternate haematopoietic lineages. EMBO J. 2010 Dec 21; Authors: Palii CG, Perez-Iratxeta C, Yao Z, Cao Y, Dai F, Davidson J, Atkins H, Allan D, Dilworth FJ, Gentleman R, Tapscott SJ, Brand M TAL1/SCL is a master regulator of haematopoiesis whose expression promotes opposite outcomes depending on the cell type: differentiation in the erythroid lineage or oncogenesis in the T-cell lineage. Here, we used a combination of ChIP sequencing and gene expression profiling to compare the function of TAL1 in normal erythroid and leukaemic T cells. Analysis of the genome-wide binding properties of TAL1 in these two haematopoietic lineages revealed new insight into the mechanism by which transcription factors select their binding sites in alternate lineages. Our study shows limited overlap in the TAL1-binding profile between the two cell types with an unexpected preference for ETS and RUNX motifs adjacent to E-boxes in the T-cell lineage. Furthermore, we show that TAL1 interacts with RUNX1 and ETS1, and that these transcription factors are critically required for TAL1 binding to genes that modulate T-cell differentiation. Thus, our findings highlight a critical role of the cellular environment in modulating transcription factor binding, and provide insight into the mechanism by which TAL1 inhibits differentiation leading to oncogenesis in the T-cell lineage. PMID: 21179004 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Calreticulin Is the Dominant Pro-Phagocytic Signal on Multiple Human Cancers and Is Counterbalanced by CD47. Sci Transl Med. 2010 Dec 22;2(63):63ra94 Authors: Chao MP, Jaiswal S, Weissman-Tsukamoto R, Alizadeh AA, Gentles AJ, Volkmer J, Weiskopf K, Willingham SB, Raveh T, Park CY, Majeti R, Weissman IL Under normal physiological conditions, cellular homeostasis is partly regulated by a balance of pro- and anti-phagocytic signals. CD47, which prevents cancer cell phagocytosis by the innate immune system, is highly expressed on several human cancers including acute myeloid leukemia, non-Hodgkin's lymphoma, and bladder cancer. Blocking CD47 with a monoclonal antibody results in phagocytosis of cancer cells and leads to in vivo tumor elimination, yet normal cells remain mostly unaffected. Thus, we postulated that cancer cells must also display a potent pro-phagocytic signal. Here, we identified calreticulin as a pro-phagocytic signal that was highly expressed on the surface of several human cancers, but was minimally expressed on most normal cells. Increased CD47 expression correlated with high amounts of calreticulin on cancer cells and was necessary for protection from calreticulin-mediated phagocytosis. Blocking the interaction of target cell calreticulin with its receptor, low-density lipoprotein receptor-related protein, on phagocytic cells prevented anti-CD47 antibody-mediated phagocytosis. Furthermore, increased calreticulin expression was an adverse prognostic factor in diverse tumors including neuroblastoma, bladder cancer, and non-Hodgkin's lymphoma. These findings identify calreticulin as the dominant pro-phagocytic signal on several human cancers, provide an explanation for the selective targeting of tumor cells by anti-CD47 antibody, and highlight the balance between pro- and anti-phagocytic signals in the immune evasion of cancer. PMID: 21178137 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Epigenetic mechanisms in inflammation. J Dent Res. 2011 Jan;90(1):9-17 Authors: Bayarsaihan D Epigenetic modifications occur in response to environmental changes and play a fundamental role in gene expression following environmental stimuli. Major epigenetic events include methylation and acetylation of histones and regulatory factors, DNA methylation, and small non-coding RNAs. Diet, pollution, infections, and other environmental factors have profound effects on epigenetic modifications and trigger susceptibility to diseases. Despite a growing body of literature addressing the role of the environment on gene expression, very little is known about the epigenetic pathways involved in the modulation of inflammatory and anti-inflammatory genes. This review summarizes the current knowledge about epigenetic control mechanisms during the inflammatory response. PMID: 21178119 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Bone Marrow Fat Is Inversely Related to Cortical Bone in Young and Old Subjects. J Clin Endocrinol Metab. 2010 Dec 22; Authors: Wren TA, Chung SA, Dorey FJ, Bluml S, Adams GB, Gilsanz V Objective: Recent studies suggest a close local link between bone marrow adiposity and endosteal bone formation. Using magnetic resonance imaging, we examined whether the relation between the amount of marrow fat and cortical bone is present at multiple sites along the diaphyses of the long bones of young and old males and females. Design: The relations between values for cortical bone area and percent marrow fat in each 5-mm section along the midthird of both femoral shafts were determined using magnetic resonance imaging in eight healthy young (aged <25 yr), and nine healthy old (aged >55 yr) men and women. Results: Strong inverse correlations were observed between values for cortical bone area and percent marrow fat along the shafts of all 34 femurs; r values between -0.54 to -0.97; all P values = 0.01-0.0001. The strength of this local association was comparable in the young and the elderly and in males and females. Conclusion: Our results underscore the strength of the local connections between bone and marrow adiposity. Increasing our understanding of the mechanism for this association could lead to better diagnosis and treatment approaches for osteoporosis. PMID: 21177790 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Re"evolutionary" Regenerative Medicine. JAMA. 2010 Dec 21; Authors: Blau HM, Pomerantz JH PMID: 21177496 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Therapeutic antibody targeting of CD47 eliminates human acute lymphoblastic leukemia. Cancer Res. 2010 Dec 21; Authors: Chao MP, Alizadeh AA, Tang C, Jan M, Weissman-Tsukamoto R, Zhao F, Park CY, Weissman IL, Majeti R Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy and constitutes 15% of adult leukemias. Although overall prognosis for pediatric ALL is favorable, high-risk pediatric patients, and most adult patients, have significantly worse outcomes. Multi-agent chemotherapy is standard of care for both pediatric and adult ALL, but is associated with systemic toxicity and long-term side effects, and is relatively ineffective against certain ALL subtypes. Recent efforts have focused on the development of targeted therapies for ALL including monoclonal antibodies. Here we report the identification of CD47, a protein that inhibits phagocytosis, as an antibody target in standard and high-risk ALL. CD47 was found to be more highly expressed on a subset of human ALL patient samples compared to normal cell counterparts and to be an independent predictor of survival and disease refractoriness in several ALL patient cohorts. Additionally, a blocking monoclonal antibody against CD47 enabled phagocytosis of ALL cells by macrophages in vitro, and inhibited tumor engraftment in vivo. Significantly, anti-CD47 antibody eliminated ALL in the peripheral blood, bone marrow, spleen, and liver of mice engrafted with primary human ALL. These data provide pre-clinical support for the development of an anti-CD47 antibody therapy for treatment of human ALL. PMID: 21177380 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Chinese risk stratification scoring system for coronary artery bypass grafting.] Zhonghua Xin Xue Guan Bing Za Zhi. 2010 Oct;38(10):901-904 Authors: Zheng Z, Zhang L, OBJECTIVE: To construct a scoring system for the prediction of in-hospital mortality in Chinese patients undergoing coronary artery bypass grafting (CABG). METHODS: From 2007 to 2008, complete clinical information of 9564 consecutive CABG patients was collected from Chinese coronary artery bypass grafting registry which recruited patients from 43 Chinese centers. This database was randomly divided into developmental and validation subsets (9:1). A risk model was developed using logistic regression. Calibration and discrimination characteristics were assessed in the validation dataset. Thresholds were defined for each model to distinguish different risk groups. The risk model was compared with EuroSCORE system in the validation dataset. RESULTS: In the developmental dataset, calibration by Hosmer-Lemeshow (HL) test was P = 0.44 and discrimination by area under ROC (AUC) was 0.80. In the validation dataset, HL test was P = 0.34, AUC was 0.78. The performance turned out good for all three risk groups. Superiority were found over EuroSCORE (HL P = 0.60; AUC 0.73). The scoring system identified 11 risk factors (with weights in brackets): age over 65 (65 - 69, 3; 70 - 74, 5; over 75, 6), preoperative NYHA stage (NHYA III, 3; NHYA IV, 7), chronic renal failure (6), extracardiac arteriopathy (5), chronic obstructive pulmonary disease (4), Preoperative atrial fibrillation or flutter (within two weeks) (2), left ventricular ejection fraction < 50% (4), other than elective surgery (5), combined valve procedure (4), preoperative critical state (4), BMI (> 24 kg/m(2), -2; < 18 kg/m(2), 5). CONCLUSION: This study constructs a simple, objective and accurate risk stratification system for Chinese patients undergoing CABG using the most up-to-date data. PMID: 21176633 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Biological and physicochemical characterization of a serum- and xeno-free chemically defined cryopreservation procedure for adult human progenitor cells. Cell Transplant. 2010 Dec 22; Authors: Zeisberger SM, Schulz JC, Mairhofer M, Ponsaerts P, Wouters G, Doerr D, Katsen-Globa A, Ehrbar M, Hescheler J, Hoerstrup SP, Zisch AH, Kolbus A, Zimmermann H While therapeutic cell transplantations using progenitor cells are increasingly evolving towards phase I and II clinical trials and chemically defined cell-culture is established, standardization in biobanking is still in the stage of infancy. In this study, the EU FP6-funded CRYSTAL (CRYo-banking of Stem cells for human Therapeutic AppLications) consortium aimed to validate novel Standard Operating Procedures (SOPs) to perform and validate xeno-free and chemically defined cryopreservation of human progenitor cells and to reduce the amount of the potentially toxic cryoprotectant additive (CPA) dimethyl sulfoxide (DMSO). To achieve this goal, three human adult progenitor- and stem cell populations - umbilical cord blood (UCB)-derived erythroid cells (UCB-ECs), UCB-derived endothelial colony forming cells (UCB-ECFCs), and adipose tissue (AT)-derived mesenchymal stromal cells (AT-MSCs) - were cryopreserved in chemically defined medium supplemented with 10% or 5% DMSO. Cell recovery, cell repopulation and functionality were evaluated post-thaw in comparison to cryopreservation in standard fetal bovine serum (FBS)-containing freezing medium. Even with a reduction of the DMSO CPA to 5%, post-thaw cell count and viability assays indicated no overall significant difference versus standard cryomedium. Additionally, to compare cellular morphology/membrane integrity and ice crystal formation during cryopreservation, multiphoton laser scanning cryomicroscopy (cryo-MPLSM) and scanning electron microscopy (SEM) were used. Neither cryo-MPLSM nor SEM indicated differences in membrane integrity for the tested cell populations under various conditions. Moreover, no influence was observed on functional properties of the cells following cryopreservation in chemically defined freezing medium, except for UCB-ECs which showed a significantly reduced differentiation capacity after cryopreservation in chemical defined medium supplemented with 5% DMSO. In summary, these results demonstrate the feasibility and robustness of standardized xeno-free cryopreservation of different human progenitor cells and encourage their use even more in the field of tissue-engineering and regenerative medicine. PMID: 21176408 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Simple and highly efficient method for production of endothelial cells from human embryonic stem cells. Cell Transplant. 2010 Dec 22; Authors: Tatsumi R, Suzuki Y, Sumi T, Sone M, Suemori H, Nakatsuji N Endothelial cells derived from human embryonic stem cells (hESC-ECs) hold much promise as a valuable tool for basic vascular research and for medical application such as cell transplantation or regenerative medicine. Here we have developed an efficient approach for the production of hESC-ECs. Using a differentiation method consisting of a stepwise combination of treatment with glycogen synthase kinase-3β (GSK-3β) inhibitor and culturing in vascular endothelial growth factor (VEGF)-supplemented medium, hESC-ECs are induced in 5 days with about 20% efficiency. These cells express vascular endothelial cadherin (VE-cadherin), VEGF receptor-2 (VEGFR-2), CD34, and platelet endothelial cell adhesion molecule-1 (PECAM-1). These hESC-ECs can then be isolated with 95% purity using a magnetic sorting system, and expanded to more than 100 fold within a month. The hESC-ECs thus produced exhibit the endothelial morphological characteristics and specific functions such as capillary tube formation and acetylated low-density lipoprotein uptake. We propose that our methodology is useful for efficient and large-scale production of hESC-ECs. PMID: 21176397 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Umbilical cord blood: current status and future directions. Vox Sang. 2011 Jan;100(1):150-62 Authors: McKenna DH, Brunstein CG Once considered biological waste, umbilical cord blood (UCB) has become an accepted source of haematopoietic stem cells (HSCs). With initial success in the pediatric setting, UCB transplantation continues to gain favor in the adult patient population. Novel approaches to UCB transplantation include use of two units and a variety of graft manipulations. Additional uses for UCB are currently being explored and include applications in regenerative medicine and immunotherapy. PMID: 21175665 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Acknowledgements. Regen Med. 2011 Jan;6(1):133 Authors: PMID: 21175293 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell policy in the Obama age: UK and US perspectives. Regen Med. 2011 Jan;6(1):125-32 Authors: Matthews KR, Rowland ML In this article, we compare two different approaches to establishing stem cell policy: a defined policy (the UK) and a changing policy (the US). The UK has a clear and precise policy, agreed upon and supported by lawmakers, scientists and the public. By contrast, US federal policy is continuously being updated based on balancing political ideologies and advances in science, and it only regulates federal funding. By investigating these contrasting policy approaches, we hope to demonstrate the impact of policy on stem cell research and public opinion. PMID: 21175292 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineering approaches for regenerative dentistry. Regen Med. 2011 Jan;6(1):111-24 Authors: Galler KM, D'Souza RN Although teeth can withstand enormous abrasive forces, they are susceptible to damage due to trauma, acids and bacterial attack. Conventional treatment relies on synthetic materials to fill defects and replace whole teeth, but these remain substitutes and cannot restore the tissues' physiological architecture and function. With the isolation of postnatal stem cells from various sources in the oral cavity and the development of smart materials for cell and growth factor delivery, possibilities for alternative, biology-based treatments arise. Interdisciplinary approaches are needed to move from replacement to regeneration, involving clinicians as well as biologists, stem cell researchers and material scientists. First, in order to provide an appreciation for the complexity of the tooth as a whole, its components and surrounding structures will be described. Next, the basic principles of tooth development will be presented, which can be applied to recreate signaling events and utilize them to build whole teeth. For the regeneration of individual tooth structures, the classical tissue engineering triad can be utilized, using dental stem cells, scaffold materials and relevant growth and differentiation factors. Recent successful engineering initiatives on whole teeth as well as on specific tissues such as enamel, the dentin-pulp complex or periodontal ligament will be discussed. In projecting future research directions, we conclude with a brief discussion of key components necessary to develop effective strategies for dental tissue engineering, which might enable us to implement novel regenerative strategies in clinical practice in the near future. PMID: 21175291 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Musculoskeletal tissue engineering with human umbilical cord mesenchymal stromal cells. Regen Med. 2011 Jan;6(1):95-109 Authors: Wang L, Ott L, Seshareddy K, Weiss ML, Detamore MS Multipotent mesenchymal stromal cells (MSCs) hold tremendous promise for tissue engineering and regenerative medicine, yet with so many sources of MSCs, what are the primary criteria for selecting leading candidates? Ideally, the cells will be multipotent, inexpensive, lack donor site morbidity, donor materials should be readily available in large numbers, immunocompatible, politically benign and expandable in vitro for several passages. Bone marrow MSCs do not meet all of these criteria and neither do embryonic stem cells. However, a promising new cell source is emerging in tissue engineering that appears to meet these criteria: MSCs derived from Wharton's jelly of umbilical cord MSCs. Exposed to appropriate conditions, umbilical cord MSCs can differentiate in vitro along several cell lineages such as the chondrocyte, osteoblast, adipocyte, myocyte, neuronal, pancreatic or hepatocyte lineages. In animal models, umbilical cord MSCs have demonstrated in vivo differentiation ability and promising immunocompatibility with host organs/tissues, even in xenotransplantation. In this article, we address their cellular characteristics, multipotent differentiation ability and potential for tissue engineering with an emphasis on musculoskeletal tissue engineering. PMID: 21175290 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Engineered cartilage using primary chondrocytes cultured in a porous cartilage-derived matrix. Regen Med. 2011 Jan;6(1):81-93 Authors: Cheng NC, Estes BT, Young TH, Guilak F Aim: To investigate the cell growth, matrix accumulation and mechanical properties of neocartilage formed by human or porcine articular chondrocytes on a porous, porcine cartilage-derived matrix (CDM) for use in cartilage tissue engineering. Materials & methods: We examined the physical properties, cell infiltration and matrix accumulation in different formulations of CDM and selected a CDM made of homogenized cartilage slurry as an appropriate scaffold for long-term culture of human and porcine articular chondrocytes. Results: The CDM scaffold supported growth and proliferation of both human and porcine chondrocytes. Histology and immunohistochemistry showed abundant cartilage-specific macromolecule deposition at day 28. Human chondrocytes migrated throughout the CDM, showing a relatively homogeneous distribution of new tissue accumulation, whereas porcine chondrocytes tended to form a proteoglycan-rich layer primarily on the surfaces of the scaffold. Human chondrocyte-seeded scaffolds had a significantly lower aggregate modulus and hydraulic permeability at day 28. Conclusions: These data show that a scaffold derived from native porcine articular cartilage can support neocartilage formation in the absence of exogenous growth factors. The overall characteristics and properties of the constructs depend on factors such as the concentration of CDM used, the porosity of the scaffold, and the species of chondrocytes. PMID: 21175289 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of platelet-rich plasma on dental stem cells derived from human impacted third molars. Regen Med. 2011 Jan;6(1):67-79 Authors: Lee UL, Jeon SH, Park JY, Choung PH Aim: Platelet-rich plasma (PRP) is fabricated from autologous blood and extensively used to promote soft and hard tissue healing. In the dental field, autologous PRP is widely used combined with dental implant installation and bone graft. This study will evaluate the biologic effect of PRP on the proliferation and the differentiation of human dental stem cells, and find the key cytokines inducing these effects to estimate the clinical feasibility of PRP for dental tissue engineering. Materials & methods: Venous blood was obtained from four individuals and each PRP was fabricated. The human dental stem cells were obtained from the periodontal ligament (PDL) and dental pulp of the surgically extracted human third molars and expanded in vitro. Immunocytochemical staining and flow cytometry with STRO-1 and CD146 confirmed existence of mesenchymal stem cells in the PDL and dental pulp. The effect of PRP on the proliferation of PDL stem cells (PDLSCs) and dental pulp stem cells (DPSCs) was assessed by colony-forming ability measurement, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and bromodeoxyuridine incorporation assay. Alkaline phosphatase activity and calcium deposit were measured to evaluate the mineralization effect of PRP PDLSCs and DPSCs. Alizarin red S staining was used to detect mineral nodules. Odontogenic and osteogenic gene expressions were evaluated in the PRP-treated PDLSCs and DPSCs by real-time quantitative PCR. A protein array was performed to detect the key cytokines that have an important role in the tissue regenerative effect of PRP. Results: Flow cytometry cell sorting showed that the cells from human PDL and dental pulp contained mesenchymal stem cell populations. Colony-forming ability and cellular proliferation of the dental stem cells were increased at 0.5 and 1% PRP concentration but decreased at 5% concentration. Long-term treatment with 1% PRP enhanced proliferation of the human dental stem cells PDLSCs and DPSCs by 120 h and showed the most significant enhancement at 96 h. PRP also promoted mineralization differentiation of the two kinds of dental stem cells as shown by measurement of alkaline phosphatase activity and calcium deposit under mineralization conditioned media. Increased formation of mineral nodules stained with alizarin red was observed in both PDLSCs and DPSCs after treatment with 1% PRP. Real-time quantitative PCR showed higher odontogenic and osteogenic gene expressions in PRP-treated PDLSCs and DPSCs. RANTES/CCL5 and ICAM-1 were the two key cytokines that were detected in human cytokine array with PRP. Conclusion: The appropriate concentration of the PRP treatment enhanced proliferation and mineralization differentiation of human dental stem cells. RANTES/CCL5 and ICAM-1 might play an important role in PRP-induced tissue regeneration but further study is needed to investigate the whole mechanism. PMID: 21175288 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Efficient generation and cryopreservation of cardiomyocytes derived from human embryonic stem cells. Regen Med. 2011 Jan;6(1):53-66 Authors: Xu C, Police S, Hassanipour M, Li Y, Chen Y, Priest C, O'Sullivan C, Laflamme MA, Zhu WZ, Van Biber B, Hegerova L, Yang J, Delavan-Boorsma K, Davies A, Lebkowski J, Gold JD Aim: Human embryonic stem cells (hESCs) represent a novel cell source to treat diseases such as heart failure and for use in drug screening. In this study, we aim to promote efficient generation of cardiomyocytes from hESCs by combining the current optimal techniques of controlled growth of undifferentiated cells and specific induction for cardiac differentiation. We also aim to examine whether these methods are scalable and whether the differentiated cells can be cryopreserved. Methods & results: hESCs were maintained without conditioned medium or feeders and were sequentially treated with activin A and bone morphogenetic protein-4 in a serum-free medium. This led to differentiation into cell populations containing high percentages of cardiomyocytes. The differentiated cells expressed appropriate cardiomyocyte markers and maintained contractility in culture, and the majority of the cells displayed working chamber (atrial and ventricular) type electrophysiological properties. In addition, the cell growth and differentiation process was adaptable to large culture formats. Moreover, the cardiomyocytes survived following cryopreservation, and viable cardiac grafts were detected after transplantation of cryopreserved cells into rat hearts following myocardial infarctions. Conclusion: These results demonstrate that cardiomyocytes of high quality can be efficiently generated and cryopreserved using hESCs maintained in serum-free medium, a step forward towards the application of these cells to human clinical use or drug discovery. PMID: 21175287 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Safety of autologous bone marrow mononuclear cell transplantation in patients with nonacute ischemic stroke. Regen Med. 2011 Jan;6(1):45-52 Authors: Battistella V, de Freitas GR, da Fonseca LM, Mercante D, Gutfilen B, Goldenberg RC, Vieira Dias J, Kasai-Brunswick TH, Wajnberg E, Rosado-de-Castro PH, Alves-Leon SV, Mendez-Otero R, Andre C Aims: To assess the safety and feasibility of intra-arterial transplantation of autologous bone marrow mononuclear cells in patients with middle cerebral artery ischemic stroke within 90 days of symptom onset. Patients & methods: Six patients were included in the study, and they received 1-5 × 10(8) bone marrow mononuclear cell and were evaluated using blood tests, neurological and imaging examination before treatment, and 1, 3, 7, 30, 60, 90, 120 and 180 days after transplantation. Scintigraphies were carried out 2 and 24 h after the procedure to analyze the biodistribution of labeled cells. Electroencephalogram was conducted within 7 days after transplantation. Results: No patients exhibited any complication or adverse events during the procedure. There was no worsening in the neurological scales until the end of the follow-up. Conclusion: Intra-arterial bone marrow mononuclear cell transplantation is feasible and safe in patients with nonacute ischemic strokes of the middle cerebral artery. Further studies are required to evaluate the efficacy of this therapy. PMID: 21175286 [PubMed - in process] | | | | | | | | | |  | |  | |  |
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