Monday, February 28, 2011

3/1 TERMSC

     
    TERMSC    
   
Proceedings of the 5th Scientific Meeting on Cartilage Engineering, February 4-5, 2010, Vandoeuvre-lès-Nancy, France.
February 28, 2011 at 2:52 AM
 

Proceedings of the 5th Scientific Meeting on Cartilage Engineering, February 4-5, 2010, Vandoeuvre-lès-Nancy, France.

Biomed Mater Eng. 2010 Jan 1;20(3):119-242

Authors:

PMID: 21351386 [PubMed - indexed for MEDLINE]

   
   
Improved sub-cellular resolution via simultaneous analysis of organelle proteomics data across varied experimental conditions.
February 28, 2011 at 2:52 AM
 

Improved sub-cellular resolution via simultaneous analysis of organelle proteomics data across varied experimental conditions.

Proteomics. 2010 Dec;10(23):4213-9

Authors: Trotter MW, Sadowski PG, Dunkley TP, Groen AJ, Lilley KS

Spatial organisation of proteins according to their function plays an important role in the specificity of their molecular interactions. Emerging proteomics methods seek to assign proteins to sub-cellular locations by partial separation of organelles and computational analysis of protein abundance distributions among partially separated fractions. Such methods permit simultaneous analysis of unpurified organelles and promise proteome-wide localisation in scenarios wherein perturbation may prompt dynamic re-distribution. Resolving organelles that display similar behavior during a protocol designed to provide partial enrichment represents a possible shortcoming. We employ the Localisation of Organelle Proteins by Isotope Tagging (LOPIT) organelle proteomics platform to demonstrate that combining information from distinct separations of the same material can improve organelle resolution and assignment of proteins to sub-cellular locations. Two previously published experiments, whose distinct gradients are alone unable to fully resolve six known protein-organelle groupings, are subjected to a rigorous analysis to assess protein-organelle association via a contemporary pattern recognition algorithm. Upon straightforward combination of single-gradient data, we observe significant improvement in protein-organelle association via both a non-linear support vector machine algorithm and partial least-squares discriminant analysis. The outcome yields suggestions for further improvements to present organelle proteomics platforms, and a robust analytical methodology via which to associate proteins with sub-cellular organelles.

PMID: 21058340 [PubMed - indexed for MEDLINE]

   
   
Genetic modification of mesenchymal stem cells for cartilage repair.
February 28, 2011 at 2:52 AM
 

Genetic modification of mesenchymal stem cells for cartilage repair.

Biomed Mater Eng. 2010 Jan 1;20(3):135-43

Authors: Cucchiarini M, Madry H

Reproduction of a native, functional architecture in articular cartilage defects is a major problem in orthopaedic surgery. The elaboration of workable options to heal damaged cartilage might necessitate to involve cellular, molecular and environmental components to allow for the formation of an adequate and stable repair tissue in sites of injury. Strategies based on the transfer of candidate sequences to progenitor cells offer powerful tools to achieve this goal. The aim of this report is to provide an overview of the most recent therapeutic approaches developed in experimental orthopaedic research.

PMID: 20930321 [PubMed - indexed for MEDLINE]

   
   
Dermal fibroblasts display similar phenotypic and differentiation capacity to fat-derived mesenchymal stem cells, but differ in anti-inflammatory and angiogenic potential.
February 28, 2011 at 2:52 AM
 

Dermal fibroblasts display similar phenotypic and differentiation capacity to fat-derived mesenchymal stem cells, but differ in anti-inflammatory and angiogenic potential.

Vasc Cell. 2011 Feb 8;3(1):5

Authors: Blasi A, Martino C, Balducci L, Saldarelli M, Soleti A, Navone SE, Canzi L, Cristini S, Invernici G, Parati EA, Alessandri G

ABSTRACT: BACKGROUND: Mesenchymal stem cells (MSCs) are multipotent stem cells able to differentiate into different cell lineages. However, MSCs represent a subpopulation of a more complex cell composition of stroma cells contained in mesenchymal tissue. Due to a lack of specific markers, it is difficult to distinguish MSCs from other more mature stromal cells such as fibroblasts, which, conversely, are abundant in mesenchymal tissue. In order to find more distinguishing features between MSCs and fibroblasts, we studied the phenotypic and functional features of human adipose-derived MSCs (AD-MSCs) side by side with normal human dermal fibroblasts (HNDFs) in vitro METHODS: AD-MSCs and HNDFs were cultured, expanded and phenotypically characterized by flow cytometry (FC). Immunofluorescence was used to investigate cell differentiation. ELISA assay was used to quantify angiogenic factors and chemokines release. Cultures of endothelial cells (ECs) and a monocyte cell line, U937, were used to test angiogenic and anti-inflammatory properties. RESULTS: Cultured AD-MSCs and HNDFs display similar morphological appearance, growth rate, and phenotypic profile. They both expressed typical mesenchymal markers-CD90, CD29, CD44, CD105 and to a minor extent, the adhesion molecules CD54, CD56, CD106 and CD166. They were negative for the stem cell markers CD34, CD146, CD133, CD117. Only aldehyde dehydrogenase (ALDH) was expressed. Neither AD-MSCs nor HNDFs differed in their multi-lineage differentiation capacity; they both differentiated into osteoblast, adipocyte, and also into cardiomyocyte-like cells. In contrast, AD-MSCs, but not HNDFs, displayed strong angiogenic and anti-inflammatory activity. AD-MSCs released significant amounts of VEGF, HGF and Angiopoietins and their conditioned medium (CM) stimulated ECs proliferation and tube formations. In addition, CM-derived AD-MSCs (AD-MSCs-CM) inhibited adhesion molecules expression on U937 and release of RANTES and MCP-1. Finally, after priming with TNFalpha, AD-MSCs enhanced their anti-inflammatory potential; while HNDFs acquired pro-inflammatory activity. CONCLUSIONS: AD-MSCs cannot be distinguished from HNDFs in vitro by evaluating their phenotypic profile or differentiation potential, but only through the analysis of their anti-inflammatory and angiogenic properties. These results underline the importance of evaluating the angiogenic and anti-inflammatory features of MSCs preparation. Their priming with inflammatory cytokines prior to transplantation may improve their efficacy in cell-based therapies for tissue regeneration.

PMID: 21349162 [PubMed - as supplied by publisher]

   
   
Roles of inflammatory and anabolic cytokines in cartilage metabolism: signals and multiple effectors converge upon MMP-13 regulation in osteoarthritis.
February 28, 2011 at 2:52 AM
 

Roles of inflammatory and anabolic cytokines in cartilage metabolism: signals and multiple effectors converge upon MMP-13 regulation in osteoarthritis.

Eur Cell Mater. 2011;21:202-20

Authors: Goldring MB, Otero M, Plumb DA, Dragomir C, Favero M, El Hachem H, Hashimoto K, Roach HI, Olivotto E, Borzì RM, Marcu KB

Human cartilage is a complex tissue of matrix proteins that vary in amount and orientation from superficial to deep layers and from loaded to unloaded zones. A major challenge to efforts to repair cartilage by stem cell-based and other tissue engineering strategies is the inability of the resident chondrocytes to lay down new matrix with the same structural and resilient properties that it had upon its original formation. This is particularly true of the collagen network, which is susceptible to cleavage once proteoglycans are depleted. Thus, a thorough understanding of the similarities and particularly the marked differences in mechanisms of cartilage remodeling during development, osteoarthritis, and aging may lead to more effective strategies for preventing cartilage damage and promoting repair. To identify and characterize effectors or regulators of cartilage remodeling in these processes, we are using culture models of primary human and mouse chondrocytes and cell lines and mouse genetic models to manipulate gene expression programs leading to matrix remodeling and subsequent chondrocyte hypertrophic differentiation, pivotal processes which both go astray in OA disease. Matrix metalloproteinases (MMP)-13, the major type II collagen-degrading collagenase, is regulated by stress-, inflammation-, and differentiation-induced signals that not only contribute to irreversible joint damage (progression) in OA, but importantly, also to the initiation/onset phase, wherein chondrocytes in articular cartilage leave their natural growth- and differentiation-arrested state. Our work points to common mediators of these processes in human OA cartilage and in early through late stages of OA in surgical and genetic mouse models.

PMID: 21351054 [PubMed - in process]

   
   
Robot-assisted partial nephrectomy: current status, techniques, and future directions.
February 28, 2011 at 2:52 AM
 

Robot-assisted partial nephrectomy: current status, techniques, and future directions.

Int Urol Nephrol. 2011 Feb 25;

Authors: Babbar P, Hemal AK

Open partial nephrectomy for the treatment of small renal masses (SRMs) concerning for renal cell carcinoma has been increasingly utilized with the increased incidental detection of SRMs and the growing recognition of the benefits of renal preservation. Laparoscopic partial nephrectomy (LPN) is a minimally invasive technique that achieves comparable oncologic and improved morbidity outcomes when compared to the open procedure. However, LPN is a technically demanding procedure resulting in a long learning curve and a lack of widespread adoption. Robot-assisted partial nephrectomy (RAPN) overcomes many of the technical hurdles of the LPN and is now coming to the forefront for the minimally invasive surgical management of SRMs. To date, the short-term oncologic outcomes of RAPN have been comparable to the open operation while providing the improved morbidity outcomes of LPN. Although encouraging, we await the long-term oncologic results of this new and promising procedure. The current bottleneck is an issue of cost and reliance on a patient-side surgeon. Future developments in instrumentation, newer robots, cost reduction, more streamlined training, increased robotic experience, and adoption by more centers will lead to greater benefit for patients with SRMs requiring nephron-sparing surgery. This review will discuss techniques for RAPN and then delve into the current status of RAPN using parameters such as warm ischemia time, blood loss, hospital stay, oncological outcomes, complications, learning curve, and quality of life. There will be an exploration of potential disadvantages associated with RAPN followed by a look at evolving techniques in regard to this groundbreaking procedure.

PMID: 21350864 [PubMed - as supplied by publisher]

   
   
Akt3 controls VEGF secretion and angiogenesis in ovarian cancer cells.
February 28, 2011 at 2:52 AM
 

Akt3 controls VEGF secretion and angiogenesis in ovarian cancer cells.

Int J Cancer. 2011 Feb 23;

Authors: Liby TA, Spyropoulos P, Lindner HB, Eldridge J, Beeson C, Hsu T, Muise-Helmericks RC

The PI3 kinase/Akt pathway is commonly deregulated in human cancers, functioning in such processes as proliferation, glucose metabolism, survival and motility. We have previously described a novel function for one of the Akt isoforms (Akt3) in primary endothelial cells: the control of VEGF-induced mitochondrial biogenesis. We sought to determine if Akt3 played a similar role in carcinoma cells. Since the PI3 kinase/Akt pathway has been strongly implicated as a key regulator in ovarian carcinoma, we tested the role of Akt3 in this tumor type. Silencing of Akt3 by shRNA did not cause an overt reduction in mitochondrial gene expression in a series of PTEN positive ovarian cancer cells. Rather, we find that blockade of Akt3, results in smaller, less vascularized tumors in a xenograft mouse model that is correlated with a reduction in VEGF expression. We find that blockade of Akt3, but not Akt1, results in a reduction in VEGF secretion and retention of VEGF protein in the endoplasmic reticulum (ER). The reduction in secretion under conditions of Akt3 blockade is, at least in part, due to the down regulation of the resident golgi protein and reported tumor cell marker, RCAS1. Conversely, over-expression of Akt3 results in an increase in RCAS1 expression and in VEGF secretion. Silencing of RCAS1 using siRNA inhibits VEGF secretion. These findings suggest an important role for Akt3 in the regulation of RCAS1 and VEGF secretion in ovarian cancer cells.

PMID: 21351097 [PubMed - as supplied by publisher]

   
   
TGF-beta1 Exposure from Bone Surfaces by Chemical Treatment Modalities.
February 28, 2011 at 2:52 AM
 

TGF-beta1 Exposure from Bone Surfaces by Chemical Treatment Modalities.

Eur Cell Mater. 2011;21:193-201

Authors: Smith EL, Colombo JS, Sloan AJ, Waddington RJ

Growth factors are known to be sequestered to the mineralised matrix of bone. The aim of this study was to investigate the ability of citric acid, EDTA, calcium hydroxide and sodium hydroxide to release active growth factors from bone surfaces, able to promote osteoblast differentiation. All chemical treatments increased surface levels of TGF-beta1 (used as a biomarker of growth factor release), compared to control bone surfaces treated with PBS. Differences were observed in the kinetics of TGF-beta1 exposure at the surface and its subsequent release into the aqueous environment for the different chemical treatments. Surface levels of growth factor following chemical treatment were low, but of sufficient concentration to stimulate cell expansion and osteoblast differentiation of bone marrow stromal cells grown on EDTA and calcium hydroxide treated surfaces compared to PBS treated surfaces. The increased osteogenic potential on these surfaces may relate to an increase in growth factor availability and changes to the surface chemistry and topography.

PMID: 21351053 [PubMed - in process]

   
   
Nomination bungle leaves CIRM leadership in limbo.
February 28, 2011 at 2:52 AM
 

Nomination bungle leaves CIRM leadership in limbo.

Nat Med. 2011 Jan;17(1):8

Authors: Dolgin E

PMID: 21217657 [PubMed - indexed for MEDLINE]

   
   
Papers from the 5th Scientific Meeting on Cartilage Engineering, February 2010, Nancy, France. Foreword.
February 28, 2011 at 2:52 AM
 

Papers from the 5th Scientific Meeting on Cartilage Engineering, February 2010, Nancy, France. Foreword.

Biomed Mater Eng. 2010 Jan 1;20(3):119

Authors: Stoltz JF, Magdalou J, Netter P, Pinzano A

PMID: 20930318 [PubMed - indexed for MEDLINE]

   
   
Unsorted human adipose tissue-derived stem cells promote angiogenesis and myogenesis in murine ischemic hindlimb model.
February 28, 2011 at 2:52 AM
 

Unsorted human adipose tissue-derived stem cells promote angiogenesis and myogenesis in murine ischemic hindlimb model.

Microvasc Res. 2010 Dec;80(3):310-6

Authors: Kang Y, Park C, Kim D, Seong CM, Kwon K, Choi C

We examined the protective effect of unsorted human adipose tissue-derived stem cells (hADSCs) with a short-term culture in endothelial differentiation medium on tissue repair after ischemic injury. hADSCs were isolated from human subcutaneous adipose tissue and cultured in vitro in endothelial differentiation medium for 2wks before transplantation. Cultured hADSCs showed a typical mesenchymal stromal cell-like phenotype, positive for endothelial-specific markers including VE-cadherin, Flt-1, eNOS, and vWF but not CD31. Two hours after ligation of the femoral artery and vein, mice were injected with the unselected hADSCs locally near the surgery site and tested for tissue perfusion and repair. Tissue perfusion rates of the ischemic limbs were significantly higher in the group treated with hADSCs compared with those of the control mice as early as post-operative day 3 (median 195.3%/min; interquartile range, 82.0-321.1 vs. median 47.1%/min; interquartile range, 18.0-58.7; p=0.001 by Friedman two-way analysis). Subsequently, the mice treated with hADSC showed better prognosis at 4wks after surgery, and the histological analysis revealed increased vascular density and reduced muscle atrophy in the hADSC-transplanted limbs. Moreover, hADSC-treated muscle contained differentiated myocytes positive for human NF-κB and myogenin antigen. These results collectively indicate that unsorted hADSCs after a 2-wk-in vitro culture have a therapeutic potential in ischemic tissue injury via inducing both angiogenesis and myogenesis.

PMID: 20510252 [PubMed - indexed for MEDLINE]

   
   
Gene Expression Profile of Dental Pulp Cells During Differentiation Into an Adipocyte Lineage.
February 28, 2011 at 2:52 AM
 

Gene Expression Profile of Dental Pulp Cells During Differentiation Into an Adipocyte Lineage.

J Pharmacol Sci. 2011 Feb 22;

Authors: Nozaki T, Ohura K

Gene regulation during in vitro differentiation into adipocytes was examined in rat dental pulp-derived cells. Insulin, 3-isobutyl-1-methylxanthine, and dexamethasone were added to induce adipogenesis. Cells containing lipid droplets were observed after induction as in 3T3 L1 cells. Rat dental pulp-derived cells showed their potential to differentiate into adipocytes in vitro. In both types of cells, the pluripotent markers Oct-3/4 and Sox2 were downregulated during differentiation, whereas the expression of Nanog was not significantly changed during differentiation. Interestingly, in the dental pulp-derived cells, the level of Oct-3/4 was transiently induced at 1 week after induction and then significantly decreased during differentiation. Based on the expression profiles determined using GeneChip Arrays, 3418 probes across 10 clusters showed a difference in expression at 1, 2, and 3 weeks after induction versus before induction. Notably, genes in the PPAR signaling pathway including Pparγ, Fabp4, and the C/EBP family were upregulated by more than 3-fold. Upregulation of the PPAR pathways seems to be a critical signal transduction pathway in this differentiation system. These findings indicate that dental pulp-derived cells are a potential source of adipogenic cells, and their gene expression profile could be useful in future regenerative medicine applications.

PMID: 21350315 [PubMed - as supplied by publisher]

   
   
Anatomical site influences the differentiation of adipose-derived stem cells for Schwann-cell phenotype and function.
February 28, 2011 at 2:52 AM
 

Anatomical site influences the differentiation of adipose-derived stem cells for Schwann-cell phenotype and function.

Glia. 2011 Feb 23;

Authors: Kaewkhaw R, Scutt AM, Haycock JW

Considerable attention has recently been given to adipose-derived stem cells (ASCs) as an important source for differentiation to Schwann cells in the treatment of peripheral nerve injury, with considerable clinical advantages over the use of mesenchymal stem cells derived from bone marrow or autologous Schwann cells. However, the relationship between adipose donor site and differentiated ASC phenotype and function is presently unknown. This work systematically studied the differentiation of ASCs harvested from three anatomical sites: (i) subcutaneous; (ii) perinephric; and (iii) epididymal adipose tissue. We show that ASC source is a major determining factor of immunophenotype, multilineage differentiation, Schwann-cell protein expression, and paracrine ability to stimulate neuronal growth. Upregulation of S100β, glial fibrillary acidic protein (GFAP), and p75NGFR was observed in differentiated ASCs from perinephric fat tissue, while only the expression of S100β or GFAP and p75NGFR was elevated in differentiated ASCs from subcutaneous or epididymal fat tissue. Although the co-culture of differentiated ASCs with NG108-15 neuronal cells demonstrated that ASCs from each source could stimulate neurite outgrowth and number, differentiated ASCs from subcutaneous and perinephric fat versus epididymal fat were most effective, which was attributed to high-brain-derived neurotropic factor/nerve growth factor and low-neurotrophin-3 levels. Thus, ASCs can be obtained from different anatomical locations, and this determines Schwann-cell phenotype upon differentiation and extent of function. This work is therefore of relevance in local therapeutic delivery of ASCs for the repair of peripheral nerve injury, but also in the broader context of ASC use in related stem-cell therapies. © 2011 Wiley-Liss, Inc.

PMID: 21351157 [PubMed - as supplied by publisher]

   
   
Defective nuclear factor-κB-inducing kinase in aly/aly mice prevents bone resorption induced by local injection of lipopolysaccharide.
February 28, 2011 at 2:52 AM
 

Defective nuclear factor-κB-inducing kinase in aly/aly mice prevents bone resorption induced by local injection of lipopolysaccharide.

J Periodontal Res. 2011 Apr;46(2):280-4

Authors: Soysa NS, Alles N, Takahashi M, Aoki K, Ohya K

Soysa NS, Alles N, Takahashi M, Aoki K, Ohya K. Defective nuclear factor-κB-inducing kinase in aly/aly mice prevents bone resorption induced by local injection of lipopolysaccharide. J Periodont Res 2011; 46: 280-284. © 2010 John Wiley & Sons A/S Background and Objective:  Nuclear factor-κB (NF-κB) is activated at sites of inflammation in many diseases, including periodontitis. Nuclear factor-κB induces the transcription of proinflammatory cytokines, resulting in increased osteoclastogenesis and bone resorption. Recently, it has been shown that the NF-κB alternative pathway is important for maintainance of physiological bone homeostasis. Activation of this pathway is by processing of the inhibitor p100 into the active subunit p52 by nuclear factor-κB-inducing kinase (NIK). Defective NIK in aly/aly mice (NIK(aly) ) causes mild osteopetrosis and blunted RANKL-stimulated osteoclastogenesis in vivo and in vitro, suggesting that NIK is necessary for basal and stimulated osteoclastogenesis. Nevertheless, the role of NIK in pathological bone resorption is not well investigated. The present study was undertaken to investigate the role of NIK in lipopolysaccharide (LPS)-induced inflammatory bone resorption using aly/aly mice. Material and Methods:  Mice were injected with LPS over the calvariae and killed 5 d later. Calvariae were subjected to radiological analysis. Histological sections were stained for tartrate-resistant acid phosphatase, and histomorphometric analysis was performed to quantify the number of osteoclasts and the area of bone resorption. Results:  Lipopolysaccharide-induced inflammation was observed in wild-type and aly/+ mice but not in aly/aly mice. Lipopolysaccharide significantly reduced the calvarial bone mineral density in wild-type and aly/+ mice, whereas bone mineral density was comparable in LPS- and vehicle-injected aly/aly mice. In addition, aly/aly mice were resistant to LPS-induced bone resorption and osteoclastogenesis. Conclusion:  Taken together, these data show that NIK is important in the bone-destructive components of inflammation and represents a possible therapeutic target.

PMID: 21348872 [PubMed - in process]

   
   
Influence of electrospun fibre mesh size on hMSC oxygen metabolism in 3D collagen matrices: Experimental and theoretical evidences.
February 28, 2011 at 2:52 AM
 

Influence of electrospun fibre mesh size on hMSC oxygen metabolism in 3D collagen matrices: Experimental and theoretical evidences.

Biotechnol Bioeng. 2011 Feb 23;

Authors: Guaccio A, Guarino V, Perez MA, Cirillo V, Netti PA, Ambrosio L

The traditional paradigm of tissue engineering of regenerating in vitro tissue or organs, through the combination of an artificial matrix and a cellular population has progressively changed direction. The most recent concept is the realization of a fully functional biohybrid, where both, the artificial and the biotic phase, concur in the formation of the novel organic matter. In this direction, interest is growing in approaches taking advantage of the control at micro- and nano- scale of cell material interaction based on the realization of elementary tassels of cells and materials which constitute the beginning point for the expansion of 3D more complex structures. Since a spontaneous assembly of all these components is expected, however, it becomes more fundamental than ever to define the features influencing cellular behaviour, either they were material functional properties, or material architecture. In this work, it has been investigated the direct effect of electrospun fibre sizes on oxygen metabolism of h-MSC cells, when any other culture parameter was kept constant. To this aim, thin PCL electrospun membranes, with micro- and nano-scale texturing, were layered between two collagen slices up to create a sandwich structure (µC-PCL-C and nC-PCL-C). Cells were seeded on membranes, and the oxygen consumption was determined by a phosphorescence quenching technique. Results indicate a strong effect of the architecture of scaffolds on cell metabolism, also revealed by the increasing of HIF1-α gene expression in nC-PCL-C. These findings offer new insights into the role of materials in specific cell activities, also implying the existence of very interesting criteria for the control of tissue growth through the tuning of scaffold architecture. Biotechnol. Bioeng. © 2011 Wiley Periodicals, Inc.

PMID: 21351071 [PubMed - as supplied by publisher]

   
   
Impact of conjugated linoleic acid on bone physiology: proposed mechanism involving inhibition of adipogenesis.
February 28, 2011 at 2:52 AM
 

Impact of conjugated linoleic acid on bone physiology: proposed mechanism involving inhibition of adipogenesis.

Nutr Rev. 2011 Mar;69(3):123-31

Authors: Ing SW, Belury MA

Conjugated linoleic acid (CLA) supplementation decreases adipose mass and increases bone mass in mice. Recent clinical studies demonstrate a beneficial effect of CLA on reducing weight and adipose mass in humans. This article reviews possible biological mechanisms of action of CLA on bone metabolism, focusing on modulation of nuclear receptor peroxisome proliferator-activated receptor gamma activity to steer mesenchymal stem cell differentiation toward an adipose and away from an osteoblast lineage. Clinical studies of the effects of CLA on bone mass and clinical implications of the effects of CLA on bone health in humans are summarized and discussed.

PMID: 21348876 [PubMed - in process]

   
   
In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses.
February 28, 2011 at 2:52 AM
 

In vitro biocompatibility and mechanical performance of titanium doped high calcium oxide metaphosphate-based glasses.

J Tissue Eng. 2010;2010:390127

Authors: Abou Neel EA, Chrzanowski W, Georgiou G, Dalby MJ, Knowles JC

This study challenged to produce phosphate-based glasses (PBG) for the treatment of osseous defects. The glasses contained, among other components, 40 mol% CaO and 1-5 mol% TiO(2). The mechanical performance and in vitro biocompatibility using both human osteosarcoma and primary osteoblasts were carried out. Incorporation of TiO(2) into PBG had no significant effect on strength and modulus. These glasses encouraged attachment and maintained high viability of osteosarcoma cells similar to the positive control surface. Cells grown directly (on glasses) or indirectly (in the presence of glass extracts) showed similar proliferation pattern to the positive control cells with no significant effect of TiO(2) detected. Increasing TiO(2) content, however, has a profound effect on cytoskeleton organization and spreading and maturation of primary osteoblasts. It is believed that TiO(2) might have acted as a chemical cue-modulating cells response, and hence the substrates supported maturation/mineralization of the primary osteoblasts.

PMID: 21350644 [PubMed - in process]

   
   
Development of porous chitosan-gelatin/hydroxyapatite composite scaffolds for hard tissue-engineering applications.
February 28, 2011 at 2:52 AM
 

Development of porous chitosan-gelatin/hydroxyapatite composite scaffolds for hard tissue-engineering applications.

J Tissue Eng Regen Med. 2011 Feb 24;

Authors: Isikli C, Hasirci V, Hasirci N

Composite scaffolds prepared from natural polymers and hydroxyapatite (HA) are expected to have enhanced osteoconductive properties and as a result gained much attention in recent years for use in bone tissue-engineering applications. Although there are various natural polymers available for this purpose, chitosan (C) and gelatin (G) are commonly studied because of their inherent properties. The aim of this study was to prepare three-dimensional (3D) scaffolds using these two natural polymers and to add either non-sintered hydroxyapatite (nsHA) or sintered hydroxyapatite (sHA) to compare their influence on physical, chemical and mechanical properties of the scaffolds and on their affinities towards Saos-2 cells. For this purpose, nsHA and sHA were synthesized and characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electron microscopy (SEM) and particle size analyses. Then nsHA and sHA particles, with average sizes of 16 µm and 6 µm, respectively, were added to the solutions of C and G during the preparation step and the resultant 3D scaffolds were characterized. Compression tests indicated that presence of nsHA or sHA increased the Young's modulus and compressive strength of the scaffolds, and the values were very similar to those of human spongy bone. MTS assays, confocal microscopy and SEM analysis showed that cell attachment and proliferation were higher on CG/sHA composite scaffolds compared to the other scaffolds. It was shown that the scaffolds prepared from chitosan, gelatin and HA are appropriate cell carriers for bone tissue engineering, especially those with sHA incorporated. Copyright © 2011 John Wiley & Sons, Ltd.

PMID: 21351375 [PubMed - as supplied by publisher]

   
   
In vivo behavior of complete human oral mucosa equivalents: characterization in athymic mice.
February 28, 2011 at 2:52 AM
 

In vivo behavior of complete human oral mucosa equivalents: characterization in athymic mice.

J Periodontal Res. 2011 Apr;46(2):214-20

Authors: Peña I, Junquera LM, Meana A, García E, Aguilar C, Fresno MF

Peña I, Junquera LM, Meana Á, García E, Aguilar C, Fresno MF. In vivo behavior of complete human oral mucosa equivalents: characterization in athymic mice. J Periodont Res 2011; 46: 214-220. © 2010 John Wiley & Sons A/S Background and Objective:  The interest in tissue engineering as a way to achieve repair of damaged body tissues has led to the carrying out of many studies whose results point to the potential effectiveness of these methods. In a previous study, we reported the obtaining of complete autologous oral mucosa equivalents (CAOMEs), characterized by oral immature keratinocytes and stem cells on an autologous plasma and fibroblast scaffold. The purpose of this study is to show their behavior in vivo, by using them as free grafts in experimental animals, and to demonstrate their potential capacity to regenerate oral mucosa. Material and Methods:  We engineered CAOMEs, as previously described. All CAOMEs thus obtained were used as free grafts in nu/nu mice. To assess their evolution in vivo, we studied their histological and immunohistochemical features by using AE1/AE3 pancytokeratin, the 5/6 cytokeratin pair, cytokeratin 13, laminin 5, collagen IV, vimentin, p-63 and Ki-67, at 7, 14 and 21 d. Results:  The structure became progressively closer to that of oral mucosa samples. Cytokeratin 5/6 staining became increasingly intense in the basal and suprabasal layers, and cytokeratin 13 was exclusively positive in the superficial layers. The basal membrane was completed in 21 d. Vimentin showed a correct formation of the chorion. The increasingly positive staining of p-63 and Ki-67 indicated that the regeneration process was taking place. Conclusion:  The present study shows the potential regenerative capacity of the CAOMEs by their ability to reach maturity similar to that seen in oral mucosa.

PMID: 21348871 [PubMed - in process]

   
   
Dermal matrix scaffold engineered with adult mesenchymal stem cells and platelet-rich plasma as a potential tool for tissue repair and regeneration.
February 28, 2011 at 2:52 AM
 

Dermal matrix scaffold engineered with adult mesenchymal stem cells and platelet-rich plasma as a potential tool for tissue repair and regeneration.

J Tissue Eng Regen Med. 2011 Feb 24;

Authors: Formigli L, Benvenuti S, Mercatelli R, Quercioli F, Tani A, Mirabella C, Dama A, Saccardi R, Mazzanti B, Cellai I, Zecchi-Orlandini S

The purpose of this study was to investigate the efficacy of Integra(®) , an artificial dermal matrix used as a dermal template for skin regeneration, to form a multifunctional scaffold with human bone marrow-derived mesenchymal stem cells (hMSCs) and platelet-rich plasma (PRP) for tissue engineering and regenerative technology. First, we showed that PRP, used as a supplement for growth medium, represented an optimal substitute for animal serum as well as a source of multiple growth factors, was able to satisfactorily support cell viability and cell proliferation and influence stemness gene expression in hMSCs. Moreover, Integra appeared to be a suitable substrate for hMSCs colonization, as judged by two-photon microscopy combined with fluorescence lifetime imaging (FLIM) and confocal analysis. The cells were then seeded on Integra + PRP for 24 and 48 h. Notably, in these conditions, the seeded cells exhibited a greater aptitude to colonize the scaffold, showed improved cell adhesion and spreading as compared with those cultured on Integra alone, and acquired a fibroblast-like phenotype, indicating that the bioengineered scaffold provided an appropriate environment for cellular growth and differentiation. In conclusion, these results, although preliminary, provide clues for the design of new therapeutic strategies for skin regeneration, consisting in the combination of mesenchymal stem cells with engineered biomaterials. Copyright © 2011 John Wiley & Sons, Ltd.

PMID: 21351374 [PubMed - as supplied by publisher]

   
   
Effects on growth and osteogenic differentiation of mesenchymal stem cells by the zinc-added sol-gel bioactive glass granules.
February 28, 2011 at 2:52 AM
 

Effects on growth and osteogenic differentiation of mesenchymal stem cells by the zinc-added sol-gel bioactive glass granules.

J Tissue Eng. 2011;2010:475260

Authors: Oh SA, Kim SH, Won JE, Kim JJ, Shin US, Kim HW

Responses of mesenchymal stem cells (MSCs) cultured with zinc-added (2 and 5%) bioactive glass granules were evaluated in terms of cell growth and osteogenic differentiation. MSCs were cultured with different quantities (3, 10 and 30) of glass granules for up to 21 days in the osteogenic medium. Cell growth was stimulated by a small quantity of glasses, particularly those that contained zinc. Osteogenic differentiation, as assessed by alkaline phosphatase activity (ALP) activity, was significantly enhanced by the glasses, particularly with large quantities of glass and for prolonged culturing. Expression of bone-sialo protein (BSP) was significantly up-regulated around the bioactive glass granules. Moreover, the zinc addition significantly altered the ALP and BSP depending on the culture time and glass quantity. Cellular mineralization was improved in all glass samples, and particularly in the 2% zinc-glass. Taken together, the zinc addition to bioactive glass induced the MSCs growth and their osteogenic differentiation, at least to the level of zinc-free glass, and with even higher level observed depending on the quantity and culture time. These findings indicate that the zinc addition to bioactive glass may be useful in development of biomaterials for the stimulation of adult stem cell in bone tissue engineering.

PMID: 21350651 [PubMed - in process]

   
   
Indirect low-intensity ultrasonic stimulation for tissue engineering.
February 28, 2011 at 2:52 AM
 

Indirect low-intensity ultrasonic stimulation for tissue engineering.

J Tissue Eng. 2010;2010:973530

Authors: Park H, Yip MC, Chertok B, Kost J, Kobler JB, Langer R, Zeitels SM

Low-intensity ultrasound (LIUS) treatment has been shown to increase mass transport, which could benefit tissue grafts during the immediate postimplant period, when blood supply to the implanted tissue is suboptimal. In this in vitro study, we investigated effects of LIUS stimulation on dye diffusion, proliferation, metabolism, and tropomyosin expression of muscle cells (C2C12) and on tissue viability and gene expression of human adipose tissue organoids. We found that LIUS increased dye diffusion within adjacent tissue culture wells and caused anisotropic diffusion patterns. This effect was confirmed by a hydrophone measurement resulting in acoustic pressure 150-341 Pa in wells. Cellular studies showed that LIUS significantly increased proliferation, metabolic activity, and expression of tropomyosin. Adipose tissue treated with LIUS showed significantly increased metabolic activity and the cells had similar morphology to normal unilocular adipocytes. Gene analysis showed that tumor necrosis factor-alpha expression (a marker for tissue damage) was significantly lower for stimulated organoids than for control groups. Our data suggests that LIUS could be a useful modality for improving graft survival in vivo.

PMID: 21350648 [PubMed - in process]

   
   
Regulatory enablers and regulatory challenges for the development of tissue-engineered products in the EU.
February 28, 2011 at 2:52 AM
 

Regulatory enablers and regulatory challenges for the development of tissue-engineered products in the EU.

Biomed Mater Eng. 2010 Jan 1;20(3):121-6

Authors: Brévignon-Dodin L

The EU Regulation on Advanced Therapy Medicinal Products (ATMP) bridges a regulatory gap and is expected to act as an enabler for the regenerative medicine sector in the EU by setting a centralised and harmonised regulatory framework for tissue-engineered products. Some of its key features are a workable and comprehensive scope, a new committee allowing for a pooling of expertise and tailored yet flexible requirements meant to keep pace with technology development. However, while providing a much needed regulatory framework, the new regulation still has potential shortfalls with regard to facilitating the research and commercialisation of tissue-engineered products in the future.

PMID: 20930319 [PubMed - indexed for MEDLINE]

   
   
The in vitro effects of dexamethasone, insulin and triiodothyronine on degenerative human intervertebral disc cells under normoxic and hypoxic conditions.
February 28, 2011 at 2:52 AM
 

The in vitro effects of dexamethasone, insulin and triiodothyronine on degenerative human intervertebral disc cells under normoxic and hypoxic conditions.

Eur Cell Mater. 2011;21:221-9

Authors: Bertolo A, Ettinger L, Aebli N, Haschtmann D, Baur M, Berlemann U, Ferguson SJ, Stoyanov JV

Degeneration of intervertebral discs (IVD) is one of the main causes of back pain and tissue engineering has been proposed as a treatment. Tissue engineering requires the use of highly expensive growth factors, which might, in addition, lack regulatory approval for human use. In an effort to find readily available differentiation factors, we tested three molecules - dexamethasone, triiodothyronine (T3) and insulin - on human IVD cells isolated after surgery, expanded in vitro and transferred into alginate beads. Triplicates containing 40 ng/ml dexamethasone, 10 nM T3 and 10 µg/ml insulin, together with a positive control (10 ng/mL transforming growth factor (TGF)-beta 1), were sampled weekly over six weeks and compared to a negative control. Furthermore, we compared the results to cultures with optimized chondrogenic media and under hypoxic condition (2% O2). Glycosaminoglycan (GAG) determination by Alcian Blue assay and histological staining showed dexamethasone to be more effective than T3 and insulin, but less than TGF-beta1. DNA quantification showed that only dexamethasone stimulated cell proliferation. qPCR demonstrated that TGF-beta1 and the optimized chondrogenic groups increased the expression of collagen type II, while aggrecan was stimulated in cultures containing dexamethasone. Hypoxia increased GAG accumulation, collagen type II and aggrecan expression, but had no effect on or even lowered cell number. In conclusion, dexamethasone is a valuable and cost-effective molecule for chondrogenic and viability induction of IVD cells under normoxic and hypoxic conditions, while insulin and T3 did not show significant differences.

PMID: 21351055 [PubMed - in process]

   
   
Intracellular signal transduction as a factor in the development of 'smart' biomaterials for bone tissue engineering.
February 28, 2011 at 2:52 AM
 

Intracellular signal transduction as a factor in the development of 'smart' biomaterials for bone tissue engineering.

Biotechnol Bioeng. 2011 Feb 23;

Authors: Zambuzzi WF, Coelho PG, Alves GG, Granjeiro JM

Signal transduction involves studying the intracellular mechanisms that govern cellular responses to external stimuli such as hormones, cytokines, and also cell adhesion to biomaterials surfaces. Several events have been shown to be responsible for cellular adhesion and adaptation onto different surfaces. For instance, cytoskeletal rearrangements during cell adhesion require the recruitment of specific protein tyrosine kinases into focal adhesion structures that promote transient focal adhesion kinase and Src phosphorylations, initially modulating cell behavior. In addition, the phosphorylation of tyrosine (Y) residues have been generally accepted as a critical regulator of a wide range of cell-related processes, including cell proliferation, migration, differentiation, survival signalling, and energy metabolism. The understanding of the signaling involved on the mechanisms of osteoblast adhesion, proliferation and differentiation on implant surfaces is fundamental for the successful design of novel "smart" materials, potentially decreasing the repair time, thereby allowing for faster patient rehabilitation. Biotechnol. Bioeng. © 2011 Wiley Periodicals, Inc.

PMID: 21351075 [PubMed - as supplied by publisher]

   
   
Matrix metalloproteinases and inhibitors in cartilage tissue engineering.
February 28, 2011 at 2:52 AM
 

Matrix metalloproteinases and inhibitors in cartilage tissue engineering.

J Tissue Eng Regen Med. 2011 Feb 24;

Authors: Li H, Feng F, Bingham CO, Elisseeff JH

Inhibiting matrix metalloproteinase (MMP) activity has been considered as a potential therapeutic treatment that may modify the outcome for osteoarthritis (OA), a disease governed by abnormalities in the balance between MMPs and their inhibitors. Due to unexpected tissue fibrosis in early-phase clinical trials with some MMP inhibitors, possible divergent effects of inhibiting MMP activity on different cells are hypothesized. Therefore, we evaluated the effects of MMP inhibition on cells relevant to cartilage tissue engineering by culturing them in vitro in poly(ethylene glycol) diacrylate hydrogels to create 3D representations of cartilage tissue while allowing for local and direct administration of inhibitors. Mesenchymal stem cells demonstrated an inhibitor concentration-dependent decrease in extracellular matrix (ECM) deposition, while normal chondrocytes were mainly affected at the highest concentration of inhibitors. In contrast, the concomitant treatment of chondrocytes from patients with OA resulted in an increase in glycosaminoglycan content only in the presence of both inhibitors and anabolic growth factors. The observed upregulation of bone markers, however, indicates a delicate balance that must be addressed to therapeutically treat OA chondrocytes to stimulate more ECM production without errant bone formation. In conclusion, this study suggests that MMPs have complex interactions in both pathobiology and homeostasis. Copyright © 2011 John Wiley & Sons, Ltd.

PMID: 21351376 [PubMed - as supplied by publisher]

   
   
Ovalbumin-based porous scaffolds for bone tissue regeneration.
February 28, 2011 at 2:52 AM
 

Ovalbumin-based porous scaffolds for bone tissue regeneration.

J Tissue Eng. 2010;2010:209860

Authors: Farrar G, Barone J, Morgan A

Cell differentiation on glutaraldehyde cross-linked ovalbumin scaffolds was the main focus of this research. Salt leaching and freeze drying were used to create a three-dimensional porous structure. Average pore size was 147.84 ± 40.36 μm and 111.79 ± 30.71 μm for surface and cross sectional area, respectively. Wet compressive strength and elastic modulus were 6.8 ± 3.6 kPa. Average glass transition temperature was 320.1 ± 1.4°C. Scaffolds were sterilized with ethylene oxide prior to seeding MC3T3-E1 cells. Cells were stained with DAPI and Texas red to determine morphology and proliferation. Average cell numbers increased between 4-hour- and 96-hour-cultured scaffolds. Alkaline phosphatase and osteocalcin levels were measured at 3, 7, 14, and 21 days. Differentiation studies showed an increase in osteocalcin at 21 days and alkaline phosphatase levels at 14 days, both indicating differentiation occurred. This work demonstrated the use of ovalbumin scaffolds for a bone tissue engineering application.

PMID: 21350641 [PubMed - in process]

   
   
A modified porous titanium sheet prepared by plasma-activated sintering for biomedical applications.
February 28, 2011 at 2:52 AM
 

A modified porous titanium sheet prepared by plasma-activated sintering for biomedical applications.

J Tissue Eng. 2011;2010:425402

Authors: Tamaki Y, Lee WS, Kataoka Y, Miyazaki T

This study aimed to develop a contamination-free porous titanium scaffold by a plasma-activated sintering within an originally developed TiN-coated graphite mold. The surface of porous titanium sheet with or without a coated graphite mold was characterized. The cell adhesion property of porous titanium sheet was also evaluated in this study. The peak of TiC was detected on the titanium sheet processed with the graphite mold without a TiN coating. Since the titanium fiber elements were directly in contact with the carbon graphite mold during processing, surface contamination was unavoidable event in this condition. The TiC peak was not detectable on the titanium sheet processed within the TiN-coated carbon graphite mold. This modified plasma-activated sintering with the TiN-coated graphite mold would be useful to fabricate a contamination-free titanium sheet. The number of adherent cells on the modified titanium sheet was greater than that of the bare titanium plate. Stress fiber formation and the extension of the cells were observed on the titanium sheets. This modified titanium sheet is expected to be a new tissue engineering material in orthopedic bone repair.

PMID: 21350650 [PubMed - in process]

   
     
 
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