| Growth factor-mediated effects on chondrogenic differentiation of mesenchymal stem cells in 3D semi-IPN poly(vinyl alcohol)-poly(caprolactone) scaffolds.
February 4, 2010 at 6:16 AM
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| | Growth factor-mediated effects on chondrogenic differentiation of mesenchymal stem cells in 3D semi-IPN poly(vinyl alcohol)-poly(caprolactone) scaffolds. J Biomed Mater Res A. 2010 Feb 2; Authors: Mohan N, Nair PD, Tabata Y Cells, signaling molecules and three-dimensional (3D) scaffolds are the major contributors to the in vitro regeneration of cartilage. This study evaluates the differentiation of mesenchymal stem cells to chondrocytes, in a 3D semi-interpenetrating polymer network (semi-IPN) scaffold that gives an appropriate niche for chondrogenic differentiation. The 3D semi-IPN scaffold poly(vinyl alcohol) and poly(caprolactone) mimics the properties of extracellular matrix of native cartilage. The chondrogenic differentiation of mesenchymal stem cells on the 3D scaffolds is carried out by supplementing signaling molecules like TGFbeta1, TGFbeta3, and BMP2 individually and in two different combinations. The results indicate that each growth factor supplement or combinations showed a different influence on cell morphology, overall distribution of cells, and secretion of cartilage specific molecules. We conclude from our results, that a combination of TGFbeta3 and BMP2 promotes be! tter differentiation of mesenchymal stem cells to chondrocytes in our scaffold. This study hence points out that an appropriate combination of 3D scaffolds and signaling molecules are required in the differentiation and maintenance of the chondrogenic phenotype during in vitro regeneration of cartilage tissue. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010. PMID: 20128001 [PubMed - as supplied by publisher] | | |
| Biodegradable poly(alpha-hydroxy acid) polymer scaffolds for bone tissue engineering.
February 4, 2010 at 6:16 AM
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| | Biodegradable poly(alpha-hydroxy acid) polymer scaffolds for bone tissue engineering. J Biomed Mater Res B Appl Biomater. 2010 Feb 2; Authors: Yu NY, Schindeler A, Little DG, Ruys AJ Synthetic graft materials are emerging as a viable alternative to autogenous bone graft and bone allograft for the treatment of critical-sized bone defects. These materials can be osteoconductive but are rarely intrinsically osteogenic, although this can be greatly enhanced by the application of bone morphogenetic proteins (BMPs). This review will discuss the versatility of biodegradable poly(alpha-hydroxy acids) for the delivery of BMPs for bone tissue engineering. Poly(alpha-hydroxy acids) have a considerable potential for customization and adaptability via modification of design parameters, including scaffold architecture, composition, and biodegradability. Different fabrication techniques will also be discussed. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010. PMID: 20127987 [PubMed - as supplied by publisher] | | |
| In Vitro High-Capacity Assay to Quantify the Clonal Heterogeneity in Trilineage Potential of Mesenchymal Stem Cells Reveals a Complex Hierarchy of Lineage Commitment.
February 4, 2010 at 6:16 AM
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| | In Vitro High-Capacity Assay to Quantify the Clonal Heterogeneity in Trilineage Potential of Mesenchymal Stem Cells Reveals a Complex Hierarchy of Lineage Commitment. Stem Cells. 2010 Feb 1; Authors: Russell KC, Phinney DG, Lacey MR, Barrilleaux BL, Meyertholen KE, O'Connor KC In regenerative medicine, bone marrow is a promising source of mesenchymal stem cells (MSCs) for a broad range of cellular therapies. This research addresses a basic prerequisite to realize the therapeutic potential of MSCs by developing a novel high-capacity assay to quantify the clonal heterogeneity in potency that is inherent to MSC preparations. The assay utilizes a 96-well format to 1) classify MSCs according to colony-forming efficiency as a measure of proliferation capacity and trilineage potential to exhibit adipo-, chondro- and osteogenesis as a measure of multipotency, and 2) preserve a frozen template of MSC clones of known potency for future use. The heterogeneity in trilineage potential of normal bone marrow MSCs is more complex than previously reported: all eight possible categories of trilineage potential were detected. In this study, the average colony-forming efficiency of MSC preparations was 55-62%, and tripotent MSCs accounted for nearly 50% of! the colony-forming cells. The multiple phenotypes detected in this study infer a more convoluted hierarchy of lineage commitment than described in the literature. Greater cell amplification, colony-forming efficiency and colony diameter for tri- vs. unipotent clones suggest that MSC proliferation may be a function of potency. CD146 may be a marker of multipotency, with approximately 2-fold difference in mean fluorescence intensity between tri- and unipotent clones. The significance of these findings is discussed in the context of the efficacy of MSC therapies. The in vitro assay described herein will likely have numerous applications given the importance of heterogeneity to the therapeutic potential of MSCs. PMID: 20127798 [PubMed - as supplied by publisher] | | |
| Phosphoproteome reveals an atlas of protein signaling networks during osteoblast adhesion.
February 4, 2010 at 6:16 AM
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| | Phosphoproteome reveals an atlas of protein signaling networks during osteoblast adhesion. J Cell Biochem. 2010 Feb 1; Authors: Milani R, Ferreira CV, Granjeiro JM, Paredes-Gamero EJ, Silva RA, Justo GZ, Nader HB, Galembeck E, Peppelenbosch MP, Aoyama H, Zambuzzi WF Cell adhesion on surfaces is a fundamental process in the emerging biomaterials field and developmental events as well. However, the mechanisms regulating this biological process in osteoblasts are not fully understood. Reversible phosphorylation catalyzed by kinases is probably the most important regulatory mechanism in eukaryotes. Therefore, the goal of this study is to assess osteoblast adhesion through a molecular prism under a peptide array technology, revealing essential signaling proteins governing adhesion-related events. First, we showed that there are main morphological changes on osteoblast shape during adhesion up to 3 h. Second, besides classical proteins activated upon integrin activation, our results showed a novel network involving signaling proteins such as Rap1A, PKA, PKC, and GSK3beta during osteoblast adhesion on polystyrene. Third, these proteins were grouped in different signaling cascades including focal adhesion establishment, cytoskeleton ! rearrangement, and cell-cycle arrest. We have thus provided evidence that a global phosphorylation screening is able to yield a systems-oriented look at osteoblast adhesion, providing new insights for understanding of bone formation and improvement of cell-substratum interactions. Altogether, these statements are necessary means for further intervention and development of new approaches for the progress of tissue engineering. J. Cell. Biochem. (c) 2010 Wiley-Liss, Inc. PMID: 20127719 [PubMed - as supplied by publisher] | | |
| BMP-7-loaded PGLA microspheres as a new delivery system for the cultivation of human chondrocytes in a collagen type I gel: the common nude mouse model.
February 4, 2010 at 6:16 AM
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| | BMP-7-loaded PGLA microspheres as a new delivery system for the cultivation of human chondrocytes in a collagen type I gel: the common nude mouse model. Int J Artif Organs. 2010 Jan 29; Authors: Gavenis K, Schneider U, Groll J, Schmidt-Rohlfing B Purpose: Bone morphogenic protein 7 (BMP-7) released from polylactide (PLGA) microspheres has proven to be a potent system in cartilage tissue engineering in vitro. However, in vivo data are still lacking. The aim of this study was to investigate this BMP-7 release system utilizing the nude mouse as a small animal model. Methods: Human osteoarthritic chondrocytes of 10 patients were enzymatically released and transferred into a collagen type-I gel. A concentration of 2x105 cells/mL was used. BMP-7 encapsulated in PGLA microspheres was added at an initial concentration of 500 ng BMP-7/mL gel. Untreated specimens and specimens with empty microspheres served as control. Samples were cultivated subcutaneously in nude mice for 6 weeks. Results: After recovery, chondrocytes of all groups displayed a spheroid morphology without signs of dedifferentiation. The proteoglycan and collagen type II content of the control groups was restricted to the immediate pericellular regi! on, whereas treatment group samples showed enhanced collagen type II production. Collagen type II and aggrecan gene expression was enhanced in treatment group samples with respect to the two control groups (mean +/- SD: 0.268 +/- 0.450 to 0.152 +/- 0.129 and 0.155 +/- 0.216 ng/ng beta-actin for collagen type II; 0.535 +/- 0.731 to 0.367 +/- 0.651 and 0.405 +/- 0.326 ng/ng beta-actin for aggrecan), whereas collagen type I gene expression decreased by a factor of 10. Relative protein quantification of collagen type II, collagen type I and proteoglycan was in accordance. Conclusions: Our data suggest that BMP-7 release from PGLA microspheres led to an improved tissue- engineered cartilage analogue in vivo with an increase in hyaline-cartilage-specific components. PMID: 20127655 [PubMed - as supplied by publisher] | | |
| European Society of Gene & Cell Therapy - 17th Annual Congress.
February 4, 2010 at 6:16 AM
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| | European Society of Gene & Cell Therapy - 17th Annual Congress. IDrugs. 2010 Feb;13(2):63-5 Authors: Chuah M The 17th Annual Congress of the European Society of Gene & Cell Therapy, held in Hanover, Germany, included topics covering new developments in the field of stem cell therapy. This conference report highlights selected presentations on stem cell gene therapy and the use of stem cells in regenerative medicine. Investigational therapies discussed include Lenti-D (Genetix Pharmaceuticals Inc/INSERM) and LentiGlobin (Genetix), a lentiviral vector-based gene transfer system containing either a human beta-globin gene or a hybrid A-gamma/beta-globin gene. PMID: 20127551 [PubMed - in process] | | |
| Polycaprolactone Scaffolds Fabricated via Bioextrusion for Tissue Engineering Applications.
February 4, 2010 at 6:16 AM
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| | Polycaprolactone Scaffolds Fabricated via Bioextrusion for Tissue Engineering Applications. Int J Biomater. 2009;2009:239643 Authors: Domingos M, Dinucci D, Cometa S, Alderighi M, Bártolo PJ, Chiellini F The most promising approach in Tissue Engineering involves the seeding of porous, biocompatible/biodegradable scaffolds, with donor cells to promote tissue regeneration. Additive biomanufacturing processes are increasingly recognized as ideal techniques to produce 3D structures with optimal pore size and spatial distribution, providing an adequate mechanical support for tissue regeneration while shaping in-growing tissues. This paper presents a novel extrusion-based system to produce 3D scaffolds with controlled internal/external geometry for TE applications.The BioExtruder is a low-cost system that uses a proper fabrication code based on the ISO programming language enabling the fabrication of multimaterial scaffolds. Poly(epsilon-caprolactone) was the material chosen to produce porous scaffolds, made by layers of directionally aligned microfilaments. Chemical, morphological, and in vitro biological evaluation performed on the polymeric constructs revealed a high! potential of the BioExtruder to produce 3D scaffolds with regular and reproducible macropore architecture, without inducing relevant chemical and biocompatibility alterations of the material. PMID: 20126577 [PubMed - in process] | | |
| Pro-Inflammatory Cytokines, IFNgamma and TNFalpha, Influence Immune Properties of Human Bone Marrow and Wharton Jelly Mesenchymal Stem Cells Differentially.
February 4, 2010 at 6:16 AM
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| | Pro-Inflammatory Cytokines, IFNgamma and TNFalpha, Influence Immune Properties of Human Bone Marrow and Wharton Jelly Mesenchymal Stem Cells Differentially. PLoS One. 2010;5(2):e9016 Authors: Prasanna SJ, Gopalakrishnan D, Shankar SR, Vasandan AB BACKGROUND: Wharton's jelly derived stem cells (WJMSCs) are gaining attention as a possible clinical alternative to bone marrow derived mesenchymal stem cells (BMMSCs) owing to better accessibility, higher expansion potential and low immunogenicity. Usage of allogenic mesenchymal stem cells (MSC) could be permissible in vivo only if they retain their immune properties in an inflammatory setting. Thus the focus of this study is to understand and compare the immune properties of BMMSCs and WJMSCs primed with key pro-inflammatory cytokines, Interferon-gamma (IFNgamma) and Tumor Necrosis Factor-alpha (TNFalpha). METHODOLOGY/PRINCIPAL FINDINGS: Initially the effect of priming on MSC mediated suppression of alloantigen and mitogen induced lymphoproliferation was evaluated in vitro. Treatment with IFNgamma or TNFalpha, did not ablate the immune-suppression caused by both the MSCs. Extent of immune-suppression was more with WJMSCs than BMMSCs in both the cases. Surprising! ly, priming BMMSCs enhanced suppression of mitogen driven lymphoproliferation only; whereas IFNgamma primed WJMSCs were better suppressors of MLRs. Further, kinetic analysis of cytokine profiles in co-cultures of primed/unprimed MSCs and Phytohematoagglutinin (PHA) activated lymphocytes was evaluated. Results indicated a decrease in levels of pro-inflammatory cytokines. Interestingly, a change in kinetics and thresholds of Interleukin-2 (IL-2) secretion was observed only with BMMSCs. Analysis of activation markers on PHA-stimulated lymphocytes indicated different expression patterns in co-cultures of primed/unprimed WJMSCs and BMMSCs. Strikingly, co-culture with WJMSCs resulted in an early activation of a negative co-stimulatory molecule, CTLA4, which was not evident with BMMSCs. A screen for immune suppressive factors in primed/unprimed WJMSCs and BMMSCs indicated inherent differences in IFNgamma inducible Indoleamine 2, 3-dioxygenase (IDO) activity, Hepatocyte growth fact! or (HGF) and Prostaglandin E-2 (PGE2) levels which could possi! bly infl uence the mechanism of immune-modulation. CONCLUSION/SIGNIFICANCE: This study demonstrates that inflammation affects the immune properties of MSCs distinctly. Importantly different tissue derived MSCs could utilize unique mechanisms of immune-modulation. PMID: 20126406 [PubMed - in process] | | |
| TRANSPORT PROPERTIES OF CARTILAGINOUS TISSUES.
February 4, 2010 at 6:16 AM
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| | TRANSPORT PROPERTIES OF CARTILAGINOUS TISSUES. Curr Rheumatol Rev. 2009 Feb 1;5(1):40-50 Authors: Jackson A, Gu W Cartilaginous tissues, such as articular cartilage and intervertebral disc, are avascular tissues which rely on transport for cellular nutrition. Comprehensive knowledge of transport properties in such tissues is therefore necessary in the understanding of nutritional supply to cells. Furthermore, poor cellular nutrition in cartilaginous tissues is believed to be a primary source of tissue degeneration, which may result in osteoarthritis (OA) or disc degeneration. In this mini-review, we present an overview of the current status of the study of transport properties and behavior in cartilaginous tissues. The mechanisms of transport in these tissues, as well as experimental approaches to measuring transport properties and results obtained are discussed. The current status of bioreactors used in cartilage tissue engineering is also presented. PMID: 20126303 [PubMed - as supplied by publisher] | | |
| Changes in blood dendritic cell counts in relation to type of coronary artery disease and brachial endothelial cell function.
February 4, 2010 at 6:16 AM
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| | Changes in blood dendritic cell counts in relation to type of coronary artery disease and brachial endothelial cell function. Coron Artery Dis. 2010 Feb 1; Authors: Van Vré EA, Van Brussel I, de Beeck KO, Hoymans VY, Vrints CJ, Bult H, Bosmans JM BACKGROUND: Recently we reported a decline of circulating myeloid (m) and plasmacytoid (p) dendritic cells (DCs) in patients with coronary artery disease (CAD). This study also determined the total blood DC numbers and focused on effects of extent (one vs. three-vessel disease) and type (stable vs. unstable) of CAD, and on endothelial cell function. METHODS: Patients undergoing diagnostic coronarography were enrolled in four groups: control patients (atypical chest pain, <50% narrowing, n=15), stable one-vessel (n=15), stable three-vessel (n=15), and unstable one-vessel CAD (n=16). Total blood DCs were identified as lineage (lin) and HLADR, and DC subtypes with blood DC antigen (BDCA)-1 for mDCs and BDCA-2 for pDCs. Flow-mediated dilatation (FMD) was measured in the brachial artery. RESULTS: Numbers of total blood DCs, mDCs and pDCs declined in CAD patients compared with control patients, but without differences between the CAD groups. Interleukin-6 and high se! nsitivity C-reactive protein displayed inverse associations with mDCs. A FMD below the median of the study population, use of beta-blockers or of lipid-lowering drugs was associated with increased mDCs, whereas pDCs were similar. Interestingly, the effects of drugs and FMD were additive with that of CAD. CONCLUSION: This study indicates that lower blood DCs do not result from medication intake or endothelial dysfunction, and are an overall systemic effect of atherosclerosis rather than CAD type (stable or unstable) or number of stenotic coronary arteries. In view of discrete associations with cytokines, FMD, beta-blockers and statins, mDCs and pDCs seem to behave differently and may influence inflammation during atherosclerosis in different ways. PMID: 20124992 [PubMed - as supplied by publisher] | | |
| Mesenchymal stem cell therapy for nonhealing cutaneous wounds.
February 4, 2010 at 6:16 AM
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| | Mesenchymal stem cell therapy for nonhealing cutaneous wounds. Plast Reconstr Surg. 2010 Feb;125(2):510-6 Authors: Hanson SE, Bentz ML, Hematti P SUMMARY:: Chronic wounds remain a major challenge in modern medicine and represent a significant burden, affecting not only physical and mental health, but also productivity, health care expenditure, and long-term morbidity. Even under optimal conditions, the healing process leads to fibrosis or scar. One promising solution, cell therapy, involves the transplantation of progenitor/stem cells to patients through local or systemic delivery, and offers a novel approach to many chronic diseases, including nonhealing wounds. Mesenchymal stem cells are multipotent, adult progenitor cells of great interest because of their unique immunologic properties and regenerative potential. A variety of preclinical and clinical studies have shown that mesenchymal stem cells may have a useful role in wound-healing and tissue-engineering strategies and both aesthetic and reconstructive surgery. Recent advances in stem cell immunobiology can offer insight into the multiple mechanisms ! through which mesenchymal stem cells could affect underlying pathophysiologic processes associated with nonhealing mesenchymal stem cells. Critical evaluation of the current literature is necessary for understanding how mesenchymal stem cells could potentially revolutionize our approach to skin and soft-tissue defects and designing clinical trials to address their role in wound repair and regeneration. PMID: 20124836 [PubMed - in process] | | |
| Human Adipose-Derived Stromal Cells Respond to and Elaborate Bone Morphogenetic Protein-2 during In Vitro Osteogenic Differentiation.
February 4, 2010 at 6:16 AM
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| | Human Adipose-Derived Stromal Cells Respond to and Elaborate Bone Morphogenetic Protein-2 during In Vitro Osteogenic Differentiation. Plast Reconstr Surg. 2010 Feb;125(2):483-93 Authors: Panetta NJ, Gupta DM, Lee JK, Wan DC, Commons GW, Longaker MT BACKGROUND:: Interest in the potential application of adipose-derived stromal cells in cell-mediated tissue engineering of bone and other mesenchymal-derived tissues is growing. This study aimed to investigate the hypothesis that human adipose-derived stromal cells respond to and elaborate bone morphogenetic protein (BMP) 2, which could represent an important target of molecular manipulation to enhance the osteogenic potential of human adipose-derived stromal cells. METHODS:: Human adipose-derived stromal cells were differentiated for 10 days toward the osteogenic lineage in osteogenic differentiation media alone or supplemented with recombinant human BMP2 (rhBMP2). Alizarin red staining was quantified by spectrophotometry. Gene expression analyses were performed using quantitative real-time polymerase chain reaction. BMP2 levels in conditioned media were titered by enzyme-linked immunosorbent assay daily during osteogenic differentiation. Human adipose-derived st! romal cells were cultured in complete or partially (50 percent) changed osteogenic differentiation media, or unchanged osteogenic differentiation media, to assay for pro-osteogenic secreted factors. In addition, human adipose-derived stromal cells were cultured in osteogenic differentiation media supplemented with BMP2/BMP4-neutralizing antibody. RESULTS:: Exogenous rhBMP2 significantly augmented the in vitro osteogenic potential of human adipose-derived stromal cells in a dose-dependent fashion, and significantly increased transcript levels of RUNX2 and osteocalcin. BMP2, BMP4, BMPR1B, and SMAD1/5 expression was significantly increased during differentiation. Enzyme-linked immunosorbent assay demonstrated significantly increased BMP2 elaboration during differentiation. Culture in conditioned osteogenic differentiation media led to significantly increased matrix mineralization. Mineralization was significantly decreased when osteogenic differentiation media was supplemented! with a BMP2/BMP4-neutralizing antibody. CONCLUSIONS:: These d! ata stro ngly support that BMP signaling is dynamic and important during normal in vitro osteogenic differentiation of human adipose-derived stromal cells. Thus, BMP2 may be used to enhance the osteogenic differentiation of human adipose-derived stromal cells for bone tissue engineering. Future studies will examine the effect of rhBMP2 on osteogenic differentiation of human adipose-derived stromal cells in vivo. PMID: 20124834 [PubMed - in process] | | |
| BMPs: From Bone to Body Morphogenetic Proteins.
February 4, 2010 at 6:16 AM
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| | BMPs: From Bone to Body Morphogenetic Proteins. Sci Signal. 2010;3(107):mr1 Authors: Obradovic Wagner D, Sieber C, Bhushan R, Börgermann JH, Graf D, Knaus P The family of bone morphogenetic proteins (BMPs) comprises approximately 30 secreted cytokines that signal through transmembrane serine/threonine kinase receptors. The BMP signaling pathways are fine-tuned on multiple levels: Extracellular antagonists modify ligand activity; several co-receptors enhance or inhibit downstream signaling events through multiple mechanisms; and intracellular molecules further regulate the signaling outcome and mediate crosstalk with other pathways. BMPs affect structures and processes throughout the entire body, ranging from embryonic patterning and development through stem cells and their niches, to tissue homeostasis and regeneration. This comprehensive involvement in various tissues had not been expected by Marshall Urist, who initially discovered the ability of an unknown factor in bone to induce bone growth in muscle and subsequently suggested the name "bone morphogenetic protein." Today, recombinant BMPs are used in clinical pra! ctice for the treatment of bone and kidney disorders, and new genetically modified BMPs are emerging as promising tools in regenerative medicine and tissue engineering. Clearly, the functions of BMPs within the body are more versatile than initially suspected. To discuss modern trends in BMP signaling, leaders in the field met for the First International BMP Workshop in Berlin in September 2009. Here, we summarize new insights on the roles of BMPs in various tissues and highlight recent findings in cell, structural, and developmental biology as well as the therapeutic potential of BMPs. Finally, we conclude that BMPs today deserve to be called body morphogenetic proteins. PMID: 20124549 [PubMed - in process] | | |
| Predifferentiated adult stem cells and matrices for cardiac cell therapy.
February 4, 2010 at 6:16 AM
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| | Predifferentiated adult stem cells and matrices for cardiac cell therapy. Asian Cardiovasc Thorac Ann. 2010 Jan;18(1):79-87 Authors: Spadaccio C, Chachques E, Chello M, Covino E, Chachques JC, Genovese J Stem cell therapy is a major field of research worldwide, with increasing clinical application, especially in cardiovascular pathology. However, the best stem cell source and type with optimal safety for functional engraftment remains unclear. An intermediate cardiac precommitted phenotype expressing some of the key proteins of a mature cardiomyocyte would permit better integration into the cardiac environment. The predifferentiated cells would receive signals from the environment, thus achieving gradual and complete differentiation. In cell transplantation, survival and engraftment within the environment of the ischemic myocardium represents a challenge for all types of cells, regardless of their state of differentiation. An alternative strategy is to embed cells in a 3-dimensional structure replicating the extracellular matrix, which is crucial for full tissue restoration and prevention of ventricular remodeling. The clinical translation of cell therapy requires! avoidance of potentially harmful drugs and cytokines, and rapid off-the-shelf availability of cells. The combination of predifferentiated cells with a functionalized scaffold, locally releasing molecules tailored to promote in-situ completion of differentiation and improve homing, survival, and function, could be an exciting approach that might circumvent the potential undesired effects of growth factor administration and improve tissue restoration. PMID: 20124305 [PubMed - in process] | | |
| Establishment of ERK1/2 Bistability and Sustained Activation through Sprouty 2 and its Relevance for Epithelial Function.
February 4, 2010 at 6:16 AM
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| | Establishment of ERK1/2 Bistability and Sustained Activation through Sprouty 2 and its Relevance for Epithelial Function. Mol Cell Biol. 2010 Feb 1; Authors: Liu W, Tundwal K, Liang Q, Goplen N, Rozario S, Quayum N, Gorska M, Wenzel S, Balzar S, Alam R Our objective was to establish an experimental model of a self-sustained and bistable ERK1/2 signaling process. A single stimulation of cells with cytokines causes rapid ERK1/2 activation, which returns to baseline in 4 hr. Repeated stimulation leads to sustained activation of ERK1/2 but not JNK, p38 or STAT6. The ERK1/2 activation lasts for 3-7 days and depends upon a positive feedback mechanism involving sprouty-2. Overexpression of sprouty-2 induces and its genetic deletion abrogates ERK1/2 bistability. Sprouty-2 directly activates Fyn kinase, which then induces ERK1/2 activation. A genome-wide microarray analysis shows that the bistable pERK1/2 does not induce a high level gene transcription. This is due to its nuclear exclusion and compartmentalization to Rab5+ endosomes. Cells with sustained endosomal pERK1/2 manifest resistance against growth factor withdrawal-induced cell death. They are primed for heightened cytokine production. Epithelial cells from huma! n asthma and from a mouse model of chronic asthma manifest increased pERK1/2, which is associated with Rab5+ endosomes. The increase in pERK1/2 was associated with a simultaneous increase in sprouty 2 expression in these tissues. Thus, we have developed a cellular model of sustained ERK1/2 activation, which may provide a mechanistic understanding of self-sustained biological processes in chronic illnesses such as asthma. PMID: 20123980 [PubMed - as supplied by publisher] | | |
| The relationship between temporomandibular joint pathosis and muscle tenderness in the orofacial and neck/shoulder region.
February 4, 2010 at 6:16 AM
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| | The relationship between temporomandibular joint pathosis and muscle tenderness in the orofacial and neck/shoulder region. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Jan;109(1):86-90 Authors: Inoue E, Maekawa K, Minakuchi H, Nagamatsu-Sakaguchi C, Ono T, Matsuka Y, Clark GT, Kuboki T OBJECTIVE: The objective of this study was to investigate the association between TMJ pain/disk pathosis and the muscle tenderness pattern in the orofacial and neck/shoulder region. STUDY DESIGN: One hundred seventy-one TMD patients were divided into 4 groups, including group 1: patients with painful unilateral TMJ disk displacement (DD); group 2: patients with painless unilateral TMJ DD; group 3: patients with painless bilateral TMJ DD; and group 4: patients with a bilateral normal TMJ disk position (n = 41). Each subject underwent muscle palpation and the side-by-side number of muscle tenderness points was combined as the number of muscle tenderness points on each side. Within each group, DD with and without reduction subjects were separated into subgroups and then were analyzed. RESULTS: In group 1, the median muscle tenderness points on the side with painful TMJ DD without reduction was significantly higher than on the normal side (P = .019), whereas the palpa! tion scores for painless DD patients showed no significant difference between the DD and normal sides. CONCLUSIONS: These results indicated painful disk displacement to possibly be correlated with ipsilateral muscle tenderness. PMID: 20123380 [PubMed - as supplied by publisher] | | |
| New processing approaches in calcium phosphate cements and their applications in regenerative medicine.
February 4, 2010 at 6:16 AM
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| | New processing approaches in calcium phosphate cements and their applications in regenerative medicine. Acta Biomater. 2010 Jan 29; Authors: Ginebra MP, Espanol M, Montufar EB, Perez RA, Mestres G The key feature of calcium phosphate cements (CPC) lies in the setting reaction triggered by mixing one or more solid calcium phosphate salts with an aqueous solution. Upon mixture, the reaction takes place through a dissolution-precipitation process which is macroscopically observed by a gradual hardening of the cement paste. The precipitation of hydroxyapatite nanocrystals at body or room temperature, and the fact that those materials can be used as self-setting pastes, have been for many years the most attractive features of CPC. But the need for developing materials able to sustain bone tissue ingrowth and capable of delivering drugs and bioactive molecules, together with the continuous requirement from surgeons to develop more easily handling cements has pushed the development of new processing routes that can accommodate all these requirements, taking advantage of the possibility of manipulating the self-setting CPC paste. It is the goal of this article to p! rovide a brief overview of the new processing developments in the area of CPC and to identify the most significant achievements. PMID: 20123046 [PubMed - as supplied by publisher] | | |
| Cell and drug-delivery therapeutics for controlled renal parenchyma regeneration.
February 4, 2010 at 6:16 AM
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| | Cell and drug-delivery therapeutics for controlled renal parenchyma regeneration. Adv Drug Deliv Rev. 2010 Jan 30; Authors: Minuth WW, Denk L, Glashauser A In regenerative medicine much attention is given to stem/progenitor cells for a future therapy of acute and chronic renal failure. However, up to date sound cell biological knowledge about nephron renewal in kidney is lacking. For that reason molecular mechanisms are under intense investigation leading from stem/progenitor cells to regenerated tubules. In this coherence new biomaterials and drug delivery systems have to be elaborated showing an intense stimulation on the renewal of parenchyma. To analyze tubule regeneration a powerful culture system is of fundamental importance. An advanced technique stimulates renal stem/progenitor cells to develop numerous tubules between layers of a polyester fleece. Use of chemically defined Iscove's Modified Dulbecco's Medium (IMDM) containing aldosterone (1 x 10(-7)M) results in spatial development of renal tubules within 13days of perfusion culture. Immunohistochemistry exhibits that numerous features of a polarized epithel! ium are expressed in generated tubules. Transmission electron microscopy (TEM) illuminates that generated tubules contain a polarized epithelium with a tight junctional complex and an intact basal lamina at the basal aspect. Development of tubules depends on applied aldosterone concentration and cannot be mimicked by precursors of its synthesis pathway or by other steroid hormones. Antagonists such as spironolactone or canrenoate prevent the development of tubules. This result illuminates that the tubulogenic development is mediated via the mineralocorticoid receptor (MR). Application of geldanamycin, radicicol, quercetin or KNK 437 in combination with aldosterone blocks development of tubules by disturbing the contact between MR and heat shock proteins 90 and 70. In conclusion, for the first time generation of renal tubules can be simulated under controlled in-vitro conditions. Using this model the effect of numerous innovative biomaterials and drug delivery system can be ! critically analyzed. PMID: 20122975 [PubMed - as supplied by publisher] | | |
| The intriguing links between prominin-1 (CD133), cholesterol-based membrane microdomains, remodeling of apical plasma membrane protrusions, extracellular membrane particles, and (neuro)epithelial cell differentiation.
February 4, 2010 at 6:16 AM
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| | The intriguing links between prominin-1 (CD133), cholesterol-based membrane microdomains, remodeling of apical plasma membrane protrusions, extracellular membrane particles, and (neuro)epithelial cell differentiation. FEBS Lett. 2010 Jan 29; Authors: Corbeil D, Marzesco AM, Wilsch-Bräuninger M, Huttner WB Prominin-1 (CD133) is a cholesterol-interacting pentaspan membrane protein concentrated in plasma membrane protrusions. In epithelial cells, notably neuroepithelial stem cells, prominin-1 is found in microvilli, the primary cilium and the midbody. These three types of apical membrane protrusions are subject to remodeling during (neuro)epithelial cell differentiation. The protrusion-specific localization of prominin involves its association with a distinct cholesterol-based membrane microdomain. Moreover, the three prominin-1-containing plasma membrane protrusions are the origin of at least two major subpopulations of prominin-1-containing extracellular membrane particles. Intriguingly, the release of these particles has been implicated in (neuro)epithelial cell differentiation. PMID: 20122930 [PubMed - as supplied by publisher] | | |
| Structure-property relationships of silk-modified mesoporous bioglass scaffolds.
February 4, 2010 at 6:16 AM
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| | Structure-property relationships of silk-modified mesoporous bioglass scaffolds. Biomaterials. 2010 Jan 30; Authors: Wu C, Zhang Y, Zhu Y, Friis T, Xiao Y Porous mesopore-bioglass (MBG) scaffolds have been proposed as a new class of bone regeneration materials due to their apatite-formation and drug-delivery properties; however, the material's inherent brittleness and high degradation and surface instability are major disadvantages, which compromise its mechanical strength and cytocompatibility as a biological scaffold. Silk, on the other hand, is a native biomaterial and is well characterized with respect to biocompatibility and tensile strength. In this study we set out to investigate what effects blending silk with MBG had on the physiochemical, drug-delivery and biological properties of MBG scaffolds with a view to bone tissue engineering applications. Transmission electron microscopy (TEM), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were the methods used to analyze the inner microstructure, pore size and morphology, and composition of MBG scaffolds, before and after ad! dition of silk. The effect of silk modification on the mechanical property of MBG scaffolds was determined by testing the compressive strength of the scaffolds and also compressive strength after degradation over time. The drug-delivery potential was evaluated by the release of dexamethasone (DEX) from the scaffolds. Finally, the cytocompatibility of silk-modified scaffolds was investigated by the attachment, morphology, proliferation, differentiation and bone-relative gene expression of bone marrow stromal cells (BMSCs). The results showed that silk modification improved the uniformity and continuity of pore network of MBG scaffolds, and maintained high porosity (94%) and large-pore size (200-400mum). There was a significant improvement in mechanical strength, mechanical stability, and control of burst release of DEX in silk-modified MBG scaffolds. Silk modification also appeared to provide a better environment for BMSC attachment, spreading, proliferation, and osteogenic ! differentiation on MBG scaffolds. PMID: 20122721 [PubMed - as supplied by publisher] | | |
| The osteoblastic differentiation of dental pulp stem cells and bone formation on different titanium surface textures.
February 4, 2010 at 6:16 AM
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| | The osteoblastic differentiation of dental pulp stem cells and bone formation on different titanium surface textures. Biomaterials. 2010 Jan 30; Authors: Mangano C, De Rosa A, Desiderio V, d'Aquino R, Piattelli A, De Francesco F, Tirino V, Mangano F, Papaccio G Bone Tissue Engineering (BTE) and Dental Implantology (DI) require the integration of implanted structures, with well characterized surfaces, in bone. In this work we have challenged acid-etched titanium (AET) and Laser Sintered Titanium (LST) surfaces with either human osteoblasts or stem cells from human dental pulps (DPSCs), to understand their osteointegration and clinical use capability of derived implants. DPSCs and human osteoblasts were challenged with the two titanium surfaces, either in plane cultures or in a roller apparatus within a culture chamber, for hours up to a month. During the cultures cells on the titanium surfaces were examined for histology, protein secretion and gene expression. Results show that a complete osteointegration using human DPSCs has been obtained: these cells were capable to quickly differentiate into osteoblasts and endotheliocytes and, then, able to produce bone tissue along the implant surfaces. Osteoblast differentiation of! DPSCs and bone morphogenetic protein production was obtained in a better and quicker way, when challenging stem cells with the LST surfaces. This successful BTE in a comparatively short time gives interesting data suggesting that LST is a promising alternative for clinical use in DI. PMID: 20122719 [PubMed - as supplied by publisher] | | |
| Cervical Tissue Engineering Using Silk Scaffolds and Human Cervical Cells.
February 4, 2010 at 6:16 AM
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| | Cervical Tissue Engineering Using Silk Scaffolds and Human Cervical Cells. Tissue Eng Part A. 2010 Feb 2; Authors: House M, Sanchez CC, Rice WL, Socrate S, Kaplan DL Spontaneous preterm birth is a frequent complication of pregnancy and a common cause of morbidity in childhood. Obstetricians suspect abnormalities of the cervix are implicated in a significant number of preterm births. The cervix is composed of fibrous connective tissue and undergoes significant remodeling in preparation for birth. We hypothesized that a tissue engineering strategy could be used to develop three-dimensional cervical - like tissue constructs that would be suitable for investigating cervical remodeling. Cervical cells were isolated from two premenopausal women undergoing hysterectomy for a benign gynecological condition and seeded on porous silk scaffolds in the presence or absence of dynamic culture and with 10% or 20% serum. Morphological, biochemical and mechanical properties were measured during the 8 week culture period. Cervical cells proliferated in three-dimensions and synthesized an extracellular matrix with biochemical constituents and mo! rphology similar to native tissue. Compared to static culture, dynamic culture was associated with significantly increased collagen deposition (p<0.05), sulfated glycosaminoglycan synthesis (p<0.05) and mechanical stiffness (p<0.05). Serum concentration did not affect measured variables. Relevant human tissue engineered cervical-like constructs constitute a novel model system for a range of fundamental and applied studies related to cervical remodeling. PMID: 20121593 [PubMed - as supplied by publisher] | | |
| Treatment of acute hepatic failure in mice by transplantation of mixed microencapsulation of rat hepatocytes and transgenic human fetal liver stromal cells.
February 4, 2010 at 6:16 AM
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| | Treatment of acute hepatic failure in mice by transplantation of mixed microencapsulation of rat hepatocytes and transgenic human fetal liver stromal cells. Tissue Eng Part C Methods. 2010 Feb 2; Authors: Teng Y, Wang Y, Li S, Wang W, Gu R, Guo X, Nan X, Ma X, Pei X Microencapsulation-mediated cell therapy overcomes the immune incompatibility between donor and recipient in transplantation. The aim of this study was to investigate the effects of transplantation of microcapsules containing a mixture of rat hepatocytes and human fetal liver stromal cells, engineered to produce basic fibroblast growth factor (bFGF), on acute liver failure in mice. In vitro experiments showed that different combinations of microencapsulated rat's hepatocytes and stromal cells survive, grow and function better in 3-dimensional (3-D) conditions. The metabolic activity of rat hepatocytes co-microencapsulated with human fetal liver stromal cells, particularly when engineered to produce bFGF(FLSCs/bFGF), is significantly higher than that of microcapsules with rat hepatocytes alone. Intraperitoneal transplantation of the encapsulated hepatocytes with FLSCs/bFGF increased the survival rate and improved liver function of an acute liver failure mouse model! induced by a 70% partial hepatectomy in BALB/C mice. Moreover, dramatic liver regeneration was observed 2 days after transplantation in the group that received intraperitoneal transplantations of encapsulated hepatocytes with FLSCs/bFGF. Therefore, transplantation of encapsulated hepatocytes and human FLSCs/bFGF may be a promising strategy to treat acute liver failure or related liver diseases. PMID: 20121581 [PubMed - as supplied by publisher] | | |
| Controlling the porosity and microarchitecture of hydrogels for tissue engineering.
February 4, 2010 at 6:16 AM
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| | Controlling the porosity and microarchitecture of hydrogels for tissue engineering. Tissue Eng Part B Rev. 2010 Feb 1; Authors: Annabi N, Nichol JW, Zhong X, Ji C, Koshy S, Khademhosseini A, Dehghani F Tissue engineering holds great promise for regeneration and repair of diseased tissues, making the development of tissue engineering scaffolds a topic of great interest in biomedical research. Because of their biocompatibility and similarities to native extracellular matrix (ECM), hydrogels have emerged as leading candidates for engineered tissue scaffolds. However, precise control of hydrogel properties, such as porosity, remains a challenge. Traditional techniques for creating bulk porosity in polymers have demonstrated success in hydrogels for tissue engineering, however often the conditions are incompatible with direct cell encapsulation. Emerging technologies have demonstrated the ability to control porosity and the microarchitectural features in hydrogels, creating engineered tissues with structure and function similar to native tissues. In this review, we explore the various technologies for controlling the porosity and microarchitecture within hydrogels, a! nd demonstrate successful applications of combining these techniques. PMID: 20121414 [PubMed - as supplied by publisher] | | |
| Synthesis and Characterization of Dual Stimuli Responsive Macromers Based on Poly(N-isopropylacrylamide) and Poly(vinylphosphonic acid).
February 4, 2010 at 6:16 AM
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| | Synthesis and Characterization of Dual Stimuli Responsive Macromers Based on Poly(N-isopropylacrylamide) and Poly(vinylphosphonic acid). Biomacromolecules. 2010 Feb 1; Authors: Kretlow JD, Hacker MC, Klouda L, Ma BB, Mikos AG Stimulus responsive materials hold great promise in biological applications as they can react to changes in physiological stimuli to produce a desired effect. Stimulus responsive macromers designed to respond to temperature changes at or around 37 degrees C and the presence of divalent cations were synthesized from N-isopropylacrylamide, pentaerythritol diacrylate monostearate, 2-hydroxyethyl acrylate, and vinylphosphonic acid by free radical polymerization. Monomers were incorporated into the macromers in ratios approximating the molar feed ratios, and macromers underwent thermogelation around normal body temperature (36.2-40.5 degrees C) as determined by rheology and differential scanning calorimetry. Macromers containing vinylphosphonic acid interacted with calcium ions in solution, displaying decreased sol-gel transition temperatures (27.6-34.4 degrees C in 100 mM CaCl(2)), with decreases of greater magnitude observed for macromers with higher relative vinylph! osphonic acid content. Critical micellar concentrations also decreased in a dose-dependent manner with increased vinylphosphonic acid incorporation in solutions with CaCl(2) but not in solutions with NaCl. These dually responsive macromers allow examination of the effect of increasing vinylphosphonic acid content in a macromer, which holds promise in biological applications such as drug and cell delivery or tissue engineering due to the macromer responsiveness at physiological temperatures and concentrations of calcium. PMID: 20121076 [PubMed - as supplied by publisher] | | |
| In Situ Forming Hydrogels Based on Tyramine Conjugated 4-Arm-PPO-PEO via Enzymatic Oxidative Reaction.
February 4, 2010 at 6:16 AM
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| | In Situ Forming Hydrogels Based on Tyramine Conjugated 4-Arm-PPO-PEO via Enzymatic Oxidative Reaction. Biomacromolecules. 2010 Feb 1; Authors: Park KM, Shin YM, Joung YK, Shin H, Park KD Over the past decades, hydrogels have been widely studied as biomaterials for various biomedical applications like implants, drugs and cell delivery carriers because of their high biocompatibility, high water contents and excellent permeability for nutrients and metabolites. Especially, in situ forming hydrogel systems have received much attention because of their easy application based on minimal invasive techniques. Chemical cross-linking systems fabricated using enzymatic reactions have various advantages, such as high biocompatibility and easy control of reaction rates under mild condition. In this study, we report enzyme-triggered injectable and biodegradable hydrogels composed of Tetronic-tyramine conjugates. The Tetronic-tyramine conjugates were synthesized by first reacting Tetronic with succinic anhydride and subsequent conjugation with tyramine using DCC/NHS as coupling reagents. The chemical structure of Tetronic-succinic anhydride-tyramine (Tet-SA-TA) ! copolymer was characterized by (1)H NMR and FTIR. The hydrogels were prepared from a Tet-SA-TA solution above 3 wt % in the presence of horseradish peroxidase (HRP) and H(2)O(2) under physiological conditions. Their mechanical property, gelation time, swelling ratio and degradation time were evaluated at different polymer, HRP, and H(2)O(2) concentrations. In addition, a cyto-compatibility study was performed using the MC3T3-E1 cell line. In the cytotoxicity test, it was clear that the Tet-SA-TA hydrogel had no apparent cytotoxicity except for the hydrogel formed with 0.25 wt % H(2)O(2) due to the cytotoxicity of residual H(2)O(2). In conclusion, the obtained results demonstrated that the Tet-SA-TA hydrogel has great potential for use as an injectable scaffold for tissue engineering and as a drug carrier for controlled drug delivery systems. PMID: 20121075 [PubMed - as supplied by publisher] | | |
| [Physiological and pathological consequences of a presence of germ line stem cells in adult tissues]
February 4, 2010 at 6:16 AM
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| | [Physiological and pathological consequences of a presence of germ line stem cells in adult tissues] Ginekol Pol. 2009 Dec;80(12):935-41 Authors: Ratajczak MZ, Machaliński B, Czajka R, Zuba-Surma E, Poziomkowska-Gesicka I, Słowik-Zyłka D Various therapheutic strategies employing stem cells have been proposed as the alternative, effective methods for therapy of multitude diseases, difficult to treat using standard, well-established methods. Advancing regenerative medicine, which is becoming a novel branch of clinical medicine, has high hopes of stem cells which could be used in treatment of injuried organs such as myocardium after heart infarction, brain after stroke, spinal cord after mechanical injury as well as in treatment of diabetes and Parkinson disease. Application of embryonic stem cells, harvested from developing embryos, is highly controversial. Hence, the stem/primitive cells isolated from adult tissuses are considered to be an optimal source of cells for therapy. Recently our research team has isolated a population of very primitive stem cells from adult tissues (very small embryonic-like stem cells - VSELs) that show several embryonic-like features. These cells can become an alternati! ve and more ethical source of the stem cells for therapy when compared to those isolated from the developing embryos. PMID: 20120940 [PubMed - in process] | | |
| The role of notch signaling in endothelial progenitor cell biology.
February 4, 2010 at 6:16 AM
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| | The role of notch signaling in endothelial progenitor cell biology. Trends Cardiovasc Med. 2009 Jul;19(5):170-3 Authors: Kwon SM, Alev C, Asahara T It is generally accepted that endothelial progenitor cells (EPCs) can promote postnatal neovascularization and be used for vascular regeneration, thus representing a promising new tool for the treatment of cardiovascular diseases. However, the exact molecular mechanisms and signaling pathways regulating the proliferation, differentiation, and migration of EPCs; their interaction with niche cells; and their regenerative capacity still remain elusive. The Notch signaling pathway shown to be important for the maintenance and differentiation of various stem and progenitor populations is also involved in EPC regulation. In this review, we will summarize the current knowledge about the pivotal role of Notch signaling in EPC biology and EPC-mediated vascular regeneration. PMID: 20005477 [PubMed - indexed for MEDLINE] | | |
| The development of a bioreactor to perfuse radially-confined hydrogel constructs: design and characterization of mass transport properties.
February 4, 2010 at 6:16 AM
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| | The development of a bioreactor to perfuse radially-confined hydrogel constructs: design and characterization of mass transport properties. Biorheology. 2009;46(5):417-37 Authors: Eniwumide JO, Lee DA, Bader DL Limitations to nutrient transport provide a challenge to the development of 3D tissue-engineered constructs. A heterogeneous distribution of viable cells and functional matrix within the developing tissue is a common consequence. In the present study, a bioreactor was developed to perfuse fluid through cylindrical agarose constructs. The transport and distribution of dextran molecules (FD-4, FD-500, FD-2000) within the agarose was visualized in order to determine the bioreactors effectiveness for transport enhancement. By 24 h, the perfusion bioreactor achieved 529%, 395% and 294% higher concentrations of FD-4, FD-500 and FD-2000, respectively, than those solely due to diffusion. Of particular interest was the effectiveness of the bioreactor to transport molecules to the central region of the constructs. In this respect, the perfusion bioreactor was found to increase transportation of FD-4, FD-500 and FD-2000 by 30%, 291% and 222% over that of diffusion. Articular! chondrocytes were cultured and perfused using the bioreactor. The improved molecular transport achieved led to an average 75% and 1340% increase of DNA and sulphated GAG, respectively at 20 days. More significantly was the 106% and 1603% increase of DNA and GAG, respectively, achieved at the central core of the 3D constructs. PMID: 19940357 [PubMed - indexed for MEDLINE] | | |
| Genetic ablation of caveolin-1 increases neural stem cell proliferation in the subventricular zone (SVZ) of the adult mouse brain.
February 4, 2010 at 6:16 AM
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| | Genetic ablation of caveolin-1 increases neural stem cell proliferation in the subventricular zone (SVZ) of the adult mouse brain. Cell Cycle. 2009 Dec;8(23):3978-83 Authors: Jasmin JF, Yang M, Iacovitti L, Lisanti MP Adult neural stem cells are self-renewing multipotent cells that have the potential to replace dysfunctional and/or dying neuronal cells at the site of brain injury or degeneration. Caveolins are well-known tumor-suppressor genes that were recently found to be involved in the regulation of stem cell proliferation. For instance, ablation of the caveolin-1 (Cav-1) gene in mice markedly increases the proliferation of intestinal and mammary stem cells. However, the roles of caveolins in the proliferation of adult neural stem cells still remain unknown. In this study, dual-label immunofluorescence analysis of the proliferation marker, Ki67, and the stem cell markers, nestin and Sox2, was performed on brains of 8 week-old wild-type (WT) and Cav-1 knockout (KO) mice. Our results demonstrate an increased number of Ki67-positive nuclei in the subventricular zone (SVZ) of Cav-1 KO brains. Importantly, our dual-label immunofluorescence analyses demonstrate increased co-local! ization of Ki67 with both nestin and Sox2 in the SVZ of Cav-1 KO brains. Remarkably similar results were also obtained with Cav-2 and Cav-3 KO mouse brains as well, with increased proliferation of adult neural stem cells. Thus, the SVZ of caveolin KO mouse brains displays an increased proliferation of adult neural stem cells. Caveolin proteins might represent new crucial regulators of adult neural stem cell proliferation. PMID: 19923909 [PubMed - indexed for MEDLINE] | | |
| The reverse Warburg effect: aerobic glycolysis in cancer associated fibroblasts and the tumor stroma.
February 4, 2010 at 6:16 AM
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| | The reverse Warburg effect: aerobic glycolysis in cancer associated fibroblasts and the tumor stroma. Cell Cycle. 2009 Dec;8(23):3984-4001 Authors: Pavlides S, Whitaker-Menezes D, Castello-Cros R, Flomenberg N, Witkiewicz AK, Frank PG, Casimiro MC, Wang C, Fortina P, Addya S, Pestell RG, Martinez-Outschoorn UE, Sotgia F, Lisanti MP Here, we propose a new model for understanding the Warburg effect in tumor metabolism. Our hypothesis is that epithelial cancer cells induce the Warburg effect (aerobic glycolysis) in neighboring stromal fibroblasts. These cancer-associated fibroblasts, then undergo myo-fibroblastic differentiation, and secrete lactate and pyruvate (energy metabolites resulting from aerobic glycolysis). Epithelial cancer cells could then take up these energy-rich metabolites and use them in the mitochondrial TCA cycle, thereby promoting efficient energy production (ATP generation via oxidative phosphorylation), resulting in a higher proliferative capacity. In this alternative model of tumorigenesis, the epithelial cancer cells instruct the normal stroma to transform into a wound-healing stroma, providing the necessary energy-rich micro-environment for facilitating tumor growth and angiogenesis. In essence, the fibroblastic tumor stroma would directly feed the epithelial cancer cel! ls, in a type of host-parasite relationship. We have termed this new idea the "Reverse Warburg Effect." In this scenario, the epithelial tumor cells "corrupt" the normal stroma, turning it into a factory for the production of energy-rich metabolites. This alternative model is still consistent with Warburg's original observation that tumors show a metabolic shift towards aerobic glycolysis. In support of this idea, unbiased proteomic analysis and transcriptional profiling of a new model of cancer-associated fibroblasts (caveolin-1 (Cav-1) deficient stromal cells), shows the upregulation of both (1) myo-fibroblast markers and (2) glycolytic enzymes, under normoxic conditions. We validated the expression of these proteins in the fibroblastic stroma of human breast cancer tissues that lack stromal Cav-1. Importantly, a loss of stromal Cav-1 in human breast cancers is associated with tumor recurrence, metastasis, and poor clinical outcome. Thus, an absence of stromal Cav-1 may b! e a biomarker for the "Reverse Warburg Effect," explaining its! powerfu l predictive value. PMID: 19923890 [PubMed - indexed for MEDLINE] | | |
| Magnetic resonance imaging of chondrocytes labeled with superparamagnetic iron oxide nanoparticles in tissue-engineered cartilage.
February 4, 2010 at 6:16 AM
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| | Magnetic resonance imaging of chondrocytes labeled with superparamagnetic iron oxide nanoparticles in tissue-engineered cartilage. Tissue Eng Part A. 2009 Dec;15(12):3899-910 Authors: Ramaswamy S, Greco JB, Uluer MC, Zhang Z, Zhang Z, Fishbein KW, Spencer RG The distribution of cells within tissue-engineered constructs is difficult to study through nondestructive means, such as would be required after implantation. However, cell labeling with iron-containing particles may prove to be a useful approach to this problem, because regions containing such labeled cells have been shown to be readily detectable using magnetic resonance imaging (MRI). In this study, we used the Food and Drug Administration-approved superparamagnetic iron oxide (SPIO) contrast agent Feridex in combination with transfection agents to label chondrocytes and visualize them with MRI in two different tissue-engineered cartilage constructs. Correspondence between labeled cell spatial location as determined using MRI and histology was established. The SPIO-labeling process was found not to affect the phenotype or viability of the chondrocytes or the production of major cartilage matrix constituents. We believe that this method of visualizing and track! ing chondrocytes may be useful in the further development of tissue engineered cartilage therapeutics. PMID: 19788362 [PubMed - indexed for MEDLINE] | | |
| Chondrogenic differentiation potential of osteoarthritic chondrocytes and their possible use in matrix-associated autologous chondrocyte transplantation.
February 4, 2010 at 6:16 AM
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| | Chondrogenic differentiation potential of osteoarthritic chondrocytes and their possible use in matrix-associated autologous chondrocyte transplantation. Arthritis Res Ther. 2009;11(5):R133 Authors: Dehne T, Karlsson C, Ringe J, Sittinger M, Lindahl A INTRODUCTION: Autologous chondrocyte transplantation (ACT) is a routine technique to regenerate focal cartilage lesions. However, patients with osteoarthritis (OA) are lacking an appropriate long-lasting treatment alternative, partly since it is not known if chondrocytes from OA patients have the same chondrogenic differentiation potential as chondrocytes from donors not affected by OA. METHODS: Articular chondrocytes from patients with OA undergoing total knee replacement (Mankin Score > 3, Ahlbäck Score > 2) and from patients undergoing ACT, here referred to as normal donors (ND), were isolated applying protocols used for ACT. Their chondrogenic differentiation potential was evaluated both in high-density pellet and scaffold (Hyaff-11) cultures by histological proteoglycan assessment (Bern Score) and immunohistochemistry for collagen types I and II. Chondrocytes cultured in monolayer and scaffolds were subjected to gene expression profiling using geno! me-wide oligonucleotide microarrays. Expression data were verified by using real-time PCR. RESULTS: Chondrocytes from ND and OA donors demonstrated accumulation of comparable amounts of cartilage matrix components, including sulphated proteoglycans and collagen types I and II. The mRNA expression of cartilage markers (ACAN, COL2A1, COMP, CRTL1, SOX9) and genes involved in matrix synthesis (BGN, CILP2, COL9A2, COL11A1, TIMP4) was highly induced in 3D cultures of chondrocytes from both donor groups. Genes associated with hypertrophic or OA cartilage (ALPL, COL1A1, COL3A1, COL10A1, MMP13, POSTN, PTH1R, RUNX2) were not significantly regulated between the two groups of donors. The expression of 661 genes, including COMP, FN1, and SOX9, was differentially regulated between OA and ND chondrocytes cultured in monolayer. During scaffold culture, the differences diminished between the OA and ND chondrocytes, and only 184 genes were differentially regulated. CONCLUSIONS: Only few gene! s were differentially expressed between OA and ND chondrocytes! in Hyaf f-11 culture. The risk of differentiation into hypertrophic cartilage does not seem to be increased for OA chondrocytes. Our findings suggest that the chondrogenic capacity is not significantly affected by OA, and OA chondrocytes fulfill the requirements for matrix-associated ACT. PMID: 19723327 [PubMed - indexed for MEDLINE] | | |
| Transplantation directs oocyte maturation from embryonic stem cells and provides a therapeutic strategy for female infertility.
February 4, 2010 at 6:16 AM
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| | Transplantation directs oocyte maturation from embryonic stem cells and provides a therapeutic strategy for female infertility. Hum Mol Genet. 2009 Nov 15;18(22):4376-89 Authors: Nicholas CR, Haston KM, Grewall AK, Longacre TA, Reijo Pera RA Ten to 15% of couples are infertile, with the most common causes being linked to the production of few or no oocytes or sperm. Yet, our understanding of human germ cell development is poor, at least in part due to the inaccessibility of early stages to genetic and developmental studies. Embryonic stem cells (ESCs) provide an in vitro system to study oocyte development and potentially treat female infertility. However, most studies of ESC differentiation to oocytes have not documented fundamental properties of endogenous development, making it difficult to determine the physiologic relevance of differentiated germ cells. Here, we sought to establish fundamental parameters of oocyte development during ESC differentiation to explore suitability for basic developmental genetic applications using the mouse as a model prior to translating to the human system. We demonstrate a timeline of definitive germ cell differentiation from ESCs in vitro that initially parallels en! dogenous oocyte development in vivo by single-cell expression profiling and analysis of functional milestones including responsiveness to defined maturation media, shared genetic requirement of Dazl, and entry into meiosis. However, ESC-derived oocyte maturation ultimately fails in vitro. To overcome this obstacle, we transplant ESC-derived oocytes into an ovarian niche to direct their functional maturation and, thereby, present rigorous evidence of oocyte physiologic relevance and a potential therapeutic strategy for infertility. PMID: 19696121 [PubMed - indexed for MEDLINE] | | |
| Effect of the alphaGal epitope on the response to small intestinal submucosa extracellular matrix in a nonhuman primate model.
February 4, 2010 at 6:16 AM
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| | Effect of the alphaGal epitope on the response to small intestinal submucosa extracellular matrix in a nonhuman primate model. Tissue Eng Part A. 2009 Dec;15(12):3877-88 Authors: Daly KA, Stewart-Akers AM, Hara H, Ezzelarab M, Long C, Cordero K, Johnson SA, Ayares D, Cooper DK, Badylak SF The Galalpha1,3Galbeta1,4GlcNAc-R (Gal) epitope is a major factor in the hyperacute rejection of pig organ transplants in primates. Biologic scaffold materials used for tissue reconstruction and composed of xenogeneic extracellular matrix (ECM) may contain the Gal epitope. However, the effect of this epitope upon the host response is controversial. The present study investigated the effect of the Gal epitope upon the host response to a porcine-derived ECM in an African Green monkey (Cholrocaebus aethiops) abdominal wall resection model. Histologic methods, serology, complement-dependent cytotoxicity, and gene expression profiling were used to evaluate the host response to allogeneic and both wild-type and Gal-deficient xenogeneic scaffold materials. Although expression of the Gal epitope induced an increase in serum anti-Gal antibodies in recipients, no other differences were noted in the host response between test articles. All ECM scaffolds were well tolerated a! nd showed constructive remodeling during the study period. Recipients of all test articles showed no histologic or humoral evidence of sensitization when a second scaffold was implanted 45 days after the original surgery. The findings of the present study show that the presence of the Gal epitope within a porcine-derived ECM scaffold material elicits a serum antibody response, but no adverse effect upon tissue remodeling. PMID: 19563260 [PubMed - indexed for MEDLINE] | | |
| Assessment of the intimal response to a protein-modified stent in a tissue-engineered blood vessel mimic.
February 4, 2010 at 6:16 AM
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| | Assessment of the intimal response to a protein-modified stent in a tissue-engineered blood vessel mimic. Tissue Eng Part A. 2009 Dec;15(12):3869-76 Authors: Cardinal KO, Williams SK Protein-coated intravascular stents have emerged as potential pro-healing modifications for or alternatives to anti-proliferative drug-eluting stents. To support the development of these devices, preclinical testing is required to evaluate the intimal response to new coatings and modifications. The purpose of this work was to implement a tissue-engineered blood vessel as an in vitro testing system to evaluate extracellular matrix-modified stents with regard to endothelialization of the stent surface. Stents were modified by submersion in a protein-enriched medium and were subsequently deployed within tissue-engineered blood vessels and cultivated in vitro under flow to assess the intimal response. Scanning electron microscopy, fluorescent nuclear staining with en face imaging, and histological assessments were performed 7 or 14 days postdeployment. Results illustrated accelerated cellular regeneration over protein-modified stent strut surfaces, with increased cove! rage and increased tissue thickness atop protein-modified stent struts. In addition, the intimal response to modified stents differed significantly from bare metal stents. Conclusions from this work support the use of a tissue-engineered blood vessel mimic system for evaluation of modified stent surfaces. These findings are important to stent researchers as well as laboratories developing tissue-engineered constructs. PMID: 19563259 [PubMed - indexed for MEDLINE] | | |
| Composite electrospun scaffolds for engineering tubular bone grafts.
February 4, 2010 at 6:16 AM
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| | Composite electrospun scaffolds for engineering tubular bone grafts. Tissue Eng Part A. 2009 Dec;15(12):3779-88 Authors: Ekaputra AK, Zhou Y, Cool SM, Hutmacher DW In this study, poly (epsilon-caprolactone) [PCL] and its collagen composite blend (PCL/Col) were fabricated to scaffolds using electrospinning method. Incorporated collagen was present on the surface of the fibers, and it modulated the attachment and proliferation of pig bone marrow mesenchymal cells (pBMMCs). Osteogenic differentiation markers were more pronounced when these cells were cultured on PCL/Col fibrous meshes, as determined by immunohistochemistry for collagen type I, osteopontin, and osteocalcin. Matrix mineralization was observed only on osteogenically induced PCL/Col constructs. Long bone analogs were created by wrapping osteogenic cell sheets around the PCL/Col meshes to form hollow cylindrical cell-scaffold constructs. Culturing these constructs under dynamic conditions enhanced bone-like tissue formation and mechanical strength. We conclude that electrospun PCL/Col mesh is a promising material for bone engineering applications. Its combination wi! th osteogenic cell sheets offers a novel and promising strategy for engineering of tubular bone analogs. PMID: 19527183 [PubMed - indexed for MEDLINE] | | |
| Development of bone and cartilage in tissue-engineered human middle phalanx models.
February 4, 2010 at 6:16 AM
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| | Development of bone and cartilage in tissue-engineered human middle phalanx models. Tissue Eng Part A. 2009 Dec;15(12):3765-78 Authors: Wada Y, Enjo M, Isogai N, Jacquet R, Lowder E, Landis WJ Human middle phalanges were tissue-engineered with midshaft scaffolds of poly(L-lactide-epsilon-caprolactone) [P(LA-CL)], hydroxyapatite-P(LA-CL), or beta-tricalcium phosphate-P(LA-CL) and end plate scaffolds of bovine chondrocyte-seeded polyglycolic acid. Midshafts were either wrapped with bovine periosteum or left uncovered. Constructs implanted in nude mice for up to 20 weeks were examined for cartilage and bone development as well as gene expression and protein secretion, which are important in extracellular matrix (ECM) formation and mineralization. Harvested 10- and 20-week constructs without periosteum maintained end plate cartilage but no growth plate formation. They also consisted of chondrocytes secreting type II collagen and proteoglycan, and they were composed of midshaft regions devoid of bone. In all periosteum-wrapped constructs at like times, end plate scaffolds held chondrocytes elaborating type II collagen and proteoglycan and cartilage growth pl! ates resembling normal tissue. Chondrocyte gene expression of type II collagen, aggrecan, and bone sialoprotein varied depending on midshaft composition, presence of periosteum, and length of implantation time. Periosteum produced additional cells, ECM, and mineral formation within the different midshaft scaffolds. Periosteum thus induces midshaft development and mediates chondrocyte gene expression and growth plate formation in cartilage regions of phalanges. This work is important for understanding developmental principles of tissue-engineered phalanges and by extension those of normal growth plate cartilage and bone. PMID: 19527181 [PubMed - indexed for MEDLINE] | | |
| Replacement of animal-derived collagen matrix by human fibroblast-derived dermal matrix for human skin equivalent products.
February 4, 2010 at 6:16 AM
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| | Replacement of animal-derived collagen matrix by human fibroblast-derived dermal matrix for human skin equivalent products. Biomaterials. 2009 Jan;30(1):71-8 Authors: El Ghalbzouri A, Commandeur S, Rietveld MH, Mulder AA, Willemze R Reconstructed human skin equivalents (HSEs) are representative models of human skin and widely used for research purposes and clinical applications. Traditional methods to generate HSEs are based on the seeding of human keratinocytes onto three-dimensional human fibroblast-populated non-human collagen matrices. Current HSEs have a limited lifespan of approximately 8 weeks, rendering them unsuitable for long-term studies. Here we present a new generation of HSEs being fully composed of human components and which can be cultured up to 20 weeks. This model is generated on a primary human fibroblast-derived dermal matrix. Pro-collagen type I secretion by human fibroblasts stabilized during long-term culture, providing a continuous and functional human dermal matrix. In contrast to rat-tail collagen-based HSEs, the present fibroblast-derived matrix-based HSEs contain more continuity in the number of viable cell layers in long-term cultures. In addition, these new skin ! models exhibit normal differentiation and proliferation, based on expression of K10/K15, and K16/K17, respectively. Detection of collagen types IV and VII and laminin 332 was confined to the epidermal-dermal junction, as in native skin. The presence of hemidesmosomes and anchoring fibrils was demonstrated by electron microscopy. Finally, we show that the presented HSE contained a higher concentration of the normal moisturizing factor compared to rat-tail collagen-based skin models, providing a further representation of functional normal human skin in vitro. This study, therefore, demonstrates the role of the dermal microenvironment on epidermal regeneration and lifespan in vitro. PMID: 18838164 [PubMed - indexed for MEDLINE] | | |
| A biophysical view of the interplay between mechanical forces and signaling pathways during transendothelial cell migration.
February 4, 2010 at 12:16 AM
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| | A biophysical view of the interplay between mechanical forces and signaling pathways during transendothelial cell migration. FEBS J. 2010 Jan 27; Authors: Stroka KM, Aranda-Espinoza H The vascular endothelium is exposed to an array of physical forces, including shear stress via blood flow, contact with other cells such as neighboring endothelial cells and leukocytes, and contact with the basement membrane. Endothelial cell morphology, protein expression, stiffness and cytoskeletal arrangement are all influenced by these mechanochemical forces. There are many biophysical tools that are useful in studying how forces are transmitted in endothelial cells, and these tools are also beginning to be used to investigate biophysical aspects of leukocyte transmigration, which is a ubiquitous mechanosensitive process. In particular, the stiffness of the substrate has been shown to have a significant impact on cellular behavior, and this is true for both endothelial cells and leukocytes. Thus, the stiffness of the basement membrane as an endothelial substrate, as well as the stiffness of the endothelium as a leukocyte substrate, is relevant to the process o! f transmigration. In this review, we discuss recent work that has related the biophysical aspects of endothelial cell interactions and leukocyte transmigration to the biochemical pathways and molecular interactions that take place during this process. Further use of biophysical tools to investigate the biological process of leukocyte transmigration will have implications for tissue engineering, as well as atherosclerosis, stroke and immune system disease research. PMID: 20121945 [PubMed - as supplied by publisher] | | | |
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