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| Campaign Contributions, Kleiner Perkins, iPierian and CIRM Grant
June 16, 2010 at 9:09 AM
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| A biotech company heavily backed by venture capitalists who contributed nearly $6 million to the election campaign that created the California stem cell agency was awarded a $1.5 million grant this spring from the very same agency.
The firm, iPierian, Inc., of South San Francisco, reportedly plans to seek many more millions from the California Institute for Regenerative Medicine in the near | | |
| Text of CIRM Response on iPierian Grant and Campaign Contribution
June 16, 2010 at 9:07 AM
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| Here is the text of an email June 15, 2010, from James Harrison, outside counsel to the California stem cell agency, concerning the iPierian grant.
David,
Thanks for speaking with me this morning. CIRM's Governing Board has
set conflict of interest standards that exceed the requirements of state
law, and Mr. Klein has exceeded even these standards by refraining from
holding any financial | | |
| CIRM Releases Budget Info
June 16, 2010 at 9:01 AM
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| | For those of you eager to dig into CIRM's proposed budget for next year, the agency yesterday afternoon posted a raft of documents dealing with the spending plan. At first blush, it appears to be a 21 percent increase over the budget that was approved for this fiscal year, which concludes at the end of the month. However, the spending for this year is running under budget, which would mean that | | |
| A gene therapy renaissance?
June 16, 2010 at 6:36 AM
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| | A gene therapy renaissance? J Gastroenterol Hepatol. 2010 May;25(5):848-50 Authors: Rasko JE PMID: 20546435 [PubMed - in process] | | |
| Induced Pluripotent Stem Cells: Characteristics and Perspectives.
June 16, 2010 at 6:35 AM
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| | Induced Pluripotent Stem Cells: Characteristics and Perspectives. Adv Biochem Eng Biotechnol. 2010 Jun 10; Authors: Cantz T, Martin U The induction of pluripotency in somatic cells is widely considered as a major breakthrough in regenerative medicine, because this approach provides the basis for individualized stem cell-based therapies. Moreover, with respect to cell transplantation and tissue engineering, expertise from bioengineering to transplantation medicine is now meeting basic research of stem cell biology.In this chapter, we discuss techniques, potential and possible risks of induced pluripotent stem (iPS) cells in the light of needs for patient-derived pluripotent stem cells. To this end, we compare these cells with other sources of pluripotent cells and discuss the first encouraging results of iPS cells in pharmacological research, disease modeling and cell transplantation, providing fascinating perspectives for future developments in biotechnology and regenerative medicine. PMID: 20549467 [PubMed - as supplied by publisher] | | |
| Comparative chondrogenesis of human cells in a 3D integrated experimental-computational mechanobiology model.
June 16, 2010 at 6:35 AM
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| | Comparative chondrogenesis of human cells in a 3D integrated experimental-computational mechanobiology model. Biomech Model Mechanobiol. 2010 Jun 12; Authors: Raimondi MT, Bonacina E, Candiani G, Laganà M, Rolando E, Talò G, Pezzoli D, D'Anchise R, Pietrabissa R, Moretti M We present an integrated experimental-computational mechanobiology model of chondrogenesis. The response of human articular chondrocytes to culture medium perfusion, versus perfusion associated with cyclic pressurisation, versus non-perfused culture, was compared in a pellet culture model, and multiphysic computation was used to quantify oxygen transport and flow dynamics in the various culture conditions. At 2 weeks of culture, the measured cell metabolic activity and the matrix content in collagen type II and aggrecan were greatest in the perfused+pressurised pellets. The main effects of perfusion alone, relative to static controls, were to suppress collagen type I and GAG contents, which were greatest in the non-perfused pellets. All pellets showed a peripheral layer of proliferating cells, which was thickest in the perfused pellets, and most pellets showed internal gradients in cell density and matrix composition. In perfused pellets, the computed lowest oxygen concentration was 0.075 mM (7.5% tension), the maximal oxygen flux was 477.5 nmol/m(2)/s and the maximal fluid shear stress, acting on the pellet surface, was 1.8 mPa (0.018 dyn/cm(2)). In the non-perfused pellets, the lowest oxygen concentration was 0.003 mM (0.3% tension) and the maximal oxygen flux was 102.4 nmol/m(2)/s. A local correlation was observed, between the gradients in pellet properties obtained from histology, and the oxygen fields calculated with multiphysic simulation. Our results show up-regulation of hyaline matrix protein production by human chondrocytes in response to perfusion associated with cyclic pressurisation. These results could be favourably exploited in tissue engineering applications. PMID: 20549292 [PubMed - as supplied by publisher] | | |
| In Vivo Tissue Engineering Over Wounds With Exposed Bone and Tendon: Autologous Dermal Grafting and Vacuum-assisted Closure.
June 16, 2010 at 6:35 AM
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| | In Vivo Tissue Engineering Over Wounds With Exposed Bone and Tendon: Autologous Dermal Grafting and Vacuum-assisted Closure. Ann Plast Surg. 2010 Jun 11; Authors: Kang GC, Por YC, Tan BK Flap coverage is ideal for wounds exposing bone and tendon, but technically less demanding and speedier options might be considered for small shallow wounds and for wounds with adjacent tissue loss precluding local flaps. We revisited the use of autologous dermal grafting-in combination with vacuum-assisted closure (VAC)-for such wounds.Five small- to medium-sized wounds exposing bone, joint, and/or tendon were each covered using an autologous meshed dermal graft followed by VAC application to induce granulation. Closure was completed at 2 weeks by split-thickness skin grafting over the granulating dermis graft.Complete and stable wound healing was achieved in all cases within 4 weeks of dermal grafting over exposed bone with excellent outcome at 1 year in terms of donor site healing and return to function. All healed wounds had a nearly flush profile with no bulkiness in the foot and toe region.Autologous dermal grafting with VAC is an integrated in vivo tissue engineering system in which the meshed dermis acts as an attractive scaffold for granulation within the conducive VAC-medium. As an alternative to flap surgery or dermal substitutes, the technique is simple, swift, and cost-effective for immediate closure of small shallow wounds and even multiple small wounds, exposing bone and tendon particularly in the lower legs, feet, and toes. PMID: 20548234 [PubMed - as supplied by publisher] | | |
| Influence on the Osteogenic Activity of the Human Bone Marrow Mesenchymal Stem Cells Transfected by Liposome-Mediated Recombinant Plasmid pIRES-hBMP2-hVEGF165 In Vitro.
June 16, 2010 at 6:35 AM
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| | Influence on the Osteogenic Activity of the Human Bone Marrow Mesenchymal Stem Cells Transfected by Liposome-Mediated Recombinant Plasmid pIRES-hBMP2-hVEGF165 In Vitro. Ann Plast Surg. 2010 Jun 11; Authors: Guo-Ping W, Xiao-Chuan H, Zhi-Hui Y, Li G Bone marrow mesenchymal stem cells (BMSCs) is an attractive option for use as seed cells in tissue engineering strategies. Bone morphogenetic proteins (BMPs) to be involved in the formation of various tissue types including bone, cartilage, tendon, and ligament. Vascular endothelial growth factor (VEGF) is a promising reagent for inducing angiogenesis.Constructed a coexpressing vector of human bone morphogenetic protein 2 (hBMP-2) and vascular endothelial growth factor 165 (hVEGF165). The vectors were transfected into proliferated BMSCs isolated from healthy adult bone marrow. The expression of hBMP-2 and hVEGF165 genes of BMSCs were assayed by Western-blot, and the level of alkaline phosphatase activities of BMSCs was determined by RT-PCR analysis of osteocalcin mRNA expression. The levels of collagen I by immunohistochemical staining were also determined.BMSCs transfected with reconstructed plasmid pIRES-hBMP-2-VEGF165 could secret a high level of BMP-2 and hVEGF165. The production of type I collagen, the activity of alkaline phosphatase, and the expression of osteocalcin mRNA were also significantly improved in the transfected BMSCs, compared with the control group.The exogenous hBMP-2 and hVEGF165 genes can be expressed constitutively in the transfected BMSCs, and the lineage-committed differentiation abilities of BMSCs containing combination of genes BMP-2 and VEGF165 are enhanced. PMID: 20548225 [PubMed - as supplied by publisher] | | |
| Mechanical Signals Activate Vascular Endothelial Growth Factor Receptor-2 To Upregulate Endothelial Cell Proliferation during Inflammation.
June 16, 2010 at 6:35 AM
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| | Mechanical Signals Activate Vascular Endothelial Growth Factor Receptor-2 To Upregulate Endothelial Cell Proliferation during Inflammation. J Immunol. 2010 Jun 14; Authors: Liu J, Agarwal S Signals generated by the dynamic mechanical strain critically regulate endothelial cell proliferation and angiogenesis; however, the molecular basis remains unclear. We investigated the mechanisms by which human dermal microvascular endothelial cells (HDMECs) perceive mechanical signals and relay them intracellularly to regulate gene expression and endothelial cell proliferation. HDMECs were exposed to low/physiologic levels of dynamic strain and probed for the differential activation/inhibition of kinases in the mechanosignaling cascade associated with endothelial cell gene activation. Because angiogenesis is important at inflammatory sites, we also assessed the mechanisms of mechanosignaling in the presence of an proinflammatory cytokine IL-1beta. In this article, we demonstrate that the mechanosignaling cascade is initiated by vascular endothelial growth receptor-2 (VEGFR2) activation. Mechanoactivation of VEGFR2 results in its nuclear translocation and elevation of PI3K-dependent Ser473-Akt phosphorylation. Subsequently, activated Akt inactivates the kinase activity of the serine/threonine kinase, glycogen synthase kinase-3beta (GSK3beta), via its Ser9 phosphorylation. Thus, inactive GSK3beta fails to phosphorylate cyclin D1 and prevents its proteosomal degradation and, consequently, promotes endothelial cell survival and proliferation. In the presence of IL-1beta, cyclin D1 is phosphorylated and degraded, leading to inhibition of cell proliferation. However, mechanical signals repress cyclin D1 phosphorylation and upregulate cell proliferation, despite the presence of IL-1beta. The data indicate that the VEGFR2/Akt/GSK3beta signaling cascade plays a critical role in sensing and phospho-relaying mechanical stimuli in endothelial cells. Furthermore, mechanical forces control highly interconnected networks of proinflammatory and Akt signaling cascades to upregulate endothelial cell proliferation. PMID: 20548028 [PubMed - as supplied by publisher] | | |
| Effect of microwell chip structure on cell microsphere production of various animal cells.
June 16, 2010 at 6:35 AM
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| | Effect of microwell chip structure on cell microsphere production of various animal cells. J Biosci Bioeng. 2010 Feb 25; Authors: Sakai Y, Yoshida S, Yoshiura Y, Mori R, Tamura T, Yahiro K, Mori H, Kanemura Y, Yamasaki M, Nakazawa K The formation of three-dimensional cell microspheres such as spheroids, embryoid bodies, and neurospheres has attracted attention as a useful culture technique. In this study, we investigated a technique for effective cell microsphere production by using specially prepared microchip. The basic chip design was a multimicrowell structure in triangular arrangement within a 100-mm(2) region in the center of a polymethylmethacrylate (PMMA) plate (24x24 mm(2)), the surface of which was modified with polyethylene glycol (PEG) to render it nonadhesive to cells. We also designed six similar chips with microwell diameters of 200, 300, 400, 600, 800, and 1000 mum to investigate the effect of the microwell diameter on the cell microsphere diameter. Rat hepatocytes, HepG2 cells, mouse embryonic stem (ES) cells, and mouse neural progenitor/stem (NPS) cells formed hepatocyte spheroids, HepG2 spheroids, embryoid bodies, and neurospheres, respectively, in the microwells within 5 days of culture. For all the cells, a single microsphere was formed in each microwell under all the chip conditions, and such microsphere configurations remained throughout the culture period. Furthermore, the microsphere diameters of each type of cell were strongly positively correlated with the microwell diameters of the chips, suggesting that microsphere diameter can be factitiously controlled by using different chip conditions. Thus, this chip technique is a promising cellular platform for tissue engineering or regenerative medicine research, pharmacological and toxicological studies, and fundamental studies in cell biology. PMID: 20547385 [PubMed - as supplied by publisher] | | |
| Isolation characterization of murine hepatocytes following collagenase infusion into left ventricle of heart.
June 16, 2010 at 6:35 AM
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| | Isolation characterization of murine hepatocytes following collagenase infusion into left ventricle of heart. J Biosci Bioeng. 2010 May 31; Authors: Ouji Y, Yoshikawa M, Moriya K, Nishiofuku M, Ouji-Sageshima N, Matsuda R, Nishimura F, Ishizaka S A method for obtaining mouse hepatocytes by infusing collagenase solution into the left ventricle was established. This technique was shown to be equivalent to the intra-portal infusion method and more practical, especially in postnatal mice with a small body size. PMID: 20547368 [PubMed - as supplied by publisher] | | |
| Effects of Wnt-10b on proliferation and differentiation of adult murine skin-derived CD34 and CD49f double-positive cells.
June 16, 2010 at 6:35 AM
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| | Effects of Wnt-10b on proliferation and differentiation of adult murine skin-derived CD34 and CD49f double-positive cells. J Biosci Bioeng. 2010 Mar 3; Authors: Ouji Y, Yoshikawa M, Nishiofuku M, Ouji-Sageshima N, Kubo A, Ishizaka S Although mouse Wnt-10b has been shown to play various roles in a wide range of biological actions, the effects on epithelial stem/progenitor cells in the skin have not been reported. In the present study, we investigated the effects of Wnt-10b on proliferation and differentiation of murine skin-derived CD34 and CD49f double-positive (CD34(+)CD49f(+)) cells, a supposed fraction as enriched epithelial stem/progenitor cells. The cells were prepared from dorsal skin samples obtained from young adult mice as alpha6 integrin (CD49f) and CD34 double-positive cells by fluorescent activated cell sorting (FACS), and they were cultured with or without Wnt-10b to investigate its effects on proliferation and differentiation. Involvement of canonical Wnt signaling pathway was confirmed by TOPFLASH assay, and differentiation of the CD34(+)CD49f(+) cells was assessed by RT-PCR analysis and immunocytochemical examinations. The skin-derived CD34(+)CD49f(+) cells were immunopositive for Lhx2 and expressed mRNA of classical markers for bulge stem cells, including Lhx2, keratin15, Sox9, S100a6, and NFATc1. Their proliferation was suppressed by Wnt-10b, and the markers for differentiated epithelial cells became to be expressed in the culture with Wnt-10b. These results suggest that Wnt-10b promotes differentiation of epithelial stem/progenitor cells in the skin. PMID: 20547359 [PubMed - as supplied by publisher] | | |
| Effect of a hepatocyte growth factor/heparin-immobilized collagen system on albumin synthesis and spheroid formation by hepatocytes.
June 16, 2010 at 6:35 AM
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| | Effect of a hepatocyte growth factor/heparin-immobilized collagen system on albumin synthesis and spheroid formation by hepatocytes. J Biosci Bioeng. 2010 Feb 13; Authors: Hou YT, Ijima H, Matsumoto S, Kubo T, Takei T, Sakai S, Kawakami K A hepatocyte growth factor (HGF)/heparin-immobilized collagen system was used as a synthetic extracellular matrix for hepatocyte culture. The albumin synthesis, nucleus numbers and morphology of the hepatocytes were determined separately to evaluate the hepatocyte number and hepatocyte-specific function under this system. The benefits of the HGF/heparin-immobilized collagen system for hepatocyte culture were confirmed by three types of culture methods in vitro, namely 2D film cultures, 2D gel cultures and 3D gel cultures. In 2D collagen film cultures, hepatocytes exhibited the highest albumin synthesis (1.42 mug/well/day) in HGF/heparin-immobilized collagen films at 7 days of culture. Heparin inhibited hepatocyte adhesion while HGF promoted hepatocyte migration, and spheroid formation was easily detected in HGF/heparin-immobilized collagen films. In 2D collagen gel cultures, albumin synthesis of around 15 mug/well/day was detected and maintained for more than 18 days on HGF/heparin-immobilized collagen gels. Similar findings were obtained in 3D HGF/heparin-immobilized collagen gel cultures, which exhibited albumin synthesis of up to 30 mug/well/day. The albumin synthesis by hepatocytes was two-fold higher in 3D gel cultures compared with 2D gel cultures, and was maintained for over 2 weeks compared with 2D film cultures using the HGF/heparin-immobilized collagen system. Taken together, the HGF/heparin-immobilized collagen system was effective for albumin synthesis by hepatocytes in both 2D film cultures and 3D gel cultures, and therefore shows good potential for tissue engineering use. PMID: 20547342 [PubMed - as supplied by publisher] | | |
| A Biomimetic Material with a High Bio-responsibility for Bone Reconstruction and Tissue Engineering.
June 16, 2010 at 6:35 AM
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| | A Biomimetic Material with a High Bio-responsibility for Bone Reconstruction and Tissue Engineering. J Biomater Sci Polym Ed. 2010 Jun 11; Authors: Chen X, Meng Y, Wang Y, Du C, Yang C A biomimetic composite was prepared using type-I collagen as the matrix, and particles of sol-gel-derived bioactive glass (58S), hyaluronic acid and phosphatidylserine as additives. The material has an interconnected 3-D porous structure with a porosity>85%. When incubated in simulated body fluid (SBF), the composite induced the formation of microcrystals of bone-like hydroxyapatite (HA), suggesting good bioactive properties. During the in vitro cell-culture experiment, MC3T3-E1 cells adhered to, migrated and spread on the surface of the porous composite. The material was employed to repair a 10-mm defect in a rabbit's radius. The composite was gradually degraded within 8 weeks and replaced by new bone. After 12 weeks, the bone marrow cavity was restored and the Haversian canal was noted from the histological observation. The biomimetic composite is a potential scaffold material for bone reconstruction and bone tissue engineering. PMID: 20546681 [PubMed - as supplied by publisher] | | |
| Preparation of Open Porous Hyaluronic Acid Scaffolds for Tissue Engineering Using the Ice Particulate Template Method.
June 16, 2010 at 6:35 AM
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| | Preparation of Open Porous Hyaluronic Acid Scaffolds for Tissue Engineering Using the Ice Particulate Template Method. J Biomater Sci Polym Ed. 2010 Jun 11; Authors: Ko YG, Oh HH, Kawazoe N, Tateishi T, Chen G A novel method to fabricate highly interconnected porous hyaluronic acid (HA) scaffolds with open surface pore structures was developed by using embossed ice particulates as a template. HA sponges were cross-linked by water-soluble carbodiimide (WSC) and the optimal cross-linking condition was analyzed by infrared spectroscopy. Cross-linking with 50 mM WSC in a 90% (v/v) ethanol/water solvent mixture assured the highest degree of cross-linking and most stable structure and, therefore, was used to cross-link the HA sponges. Observation with a scanning electron microscope showed that the HA scaffolds had funnel-like porous structures. There were large, open pores on the top surfaces and inner bulk pores under the top surface of the funnel-like HA sponges. The inner bulk pores were interconnected with the large, top surface pores and extended into the whole sponge. The pore morphology and density of the large, top surface pores were dependent on the dimension and density of the ice particulates. The size of the inner bulk pores was dependent on the freezing temperature. The funnel-like pore structures of the HA sponges facilitated cell penetration into the inner pores of the sponges and resulted in homogenous cell distribution in the sponges. PMID: 20546679 [PubMed - as supplied by publisher] | | |
| Spontaneous Formation of a Hydrogel Composed of Water-Soluble Phospholipid Polymers Grafted with Enantiomeric Oligo(lactic acid) Chains.
June 16, 2010 at 6:35 AM
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| | Spontaneous Formation of a Hydrogel Composed of Water-Soluble Phospholipid Polymers Grafted with Enantiomeric Oligo(lactic acid) Chains. J Biomater Sci Polym Ed. 2010 Jun 11; Authors: Takami K, Watanabe J, Takai M, Ishihara K We designed and synthesized water-soluble biocompatible and biodegradable polymers composed of 2-methacryroyloxyethyl phosphorylcholine and oligo(L- or D-lactic acid) macromonomers to develop an injectable hydrogel matrix. Aqueous solutions containing the polymers with oligo(L-lactic acid) (OLLA) and oligo(D-lactic acid) (ODLA) chains underwent spontaneous gelation when mixed together. This was due to the formation of a stereocomplex between the OLLA and ODLA side-chains, which act as cross-linking components in the hydrogel. Therefore, the hydrogel could be re-dissolved in a buffer solution by hydrolysis of the oligo(lactic acid) chains. We obtained an injectable, biocompatible and degradable hydrogel, and we anticipate that it will be used in applications involving the controlled release of bioactive molecules and cell-based tissue engineering. PMID: 20546676 [PubMed - as supplied by publisher] | | |
| Getting to the Root of dental implant tissue engineering.
June 16, 2010 at 6:35 AM
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| | Getting to the Root of dental implant tissue engineering. J Clin Periodontol. 2010 Jun 9; Authors: Giannobile WV Giannobile WV. Getting to the Root of dental implant tissue engineering. J Clin Peridontol 2010; doi: 10.1111/j.1600-051X.2010.01589.x. PMID: 20546086 [PubMed - as supplied by publisher] | | |
| Regenerative medicine in dermatology: biomaterials, tissue engineering, stem cells, gene transfer and beyond.
June 16, 2010 at 6:35 AM
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| | Regenerative medicine in dermatology: biomaterials, tissue engineering, stem cells, gene transfer and beyond. Exp Dermatol. 2010 Jun 9; Authors: Dieckmann C, Renner R, Milkova L, Simon JC Please cite this paper as: Regenerative medicine in dermatology: biomaterials, tissue engineering, stem cells, gene transfer and beyond. Experimental Dermatology 2010. Abstract: The term 'regenerative medicine' refers to a new and expanding field in biomedical research that focuses on the development of innovative therapies allowing the body to replace, restore and regenerate damaged or diseased cells, tissues and organs. It combines several technological approaches including the use of soluble molecules, biomaterials, tissue engineering, gene therapy, stem cell transplantation and the reprogramming of cell and tissue types. Because of its easy accessibility, skin is becoming an attractive model organ for regenerative medicine. Here, we review recent developments in regenerative medicine and their potential relevance for dermatology with a particular emphasis on biomaterials, tissue engineering, skin substitutes and stem cell-based therapies for skin reconstitution in patients suffering from chronic wounds and extensive burns. PMID: 20545761 [PubMed - as supplied by publisher] | | |
| Engineering Endostatin-Producing Cartilaginous Constructs for Cartilage Repair Using Nonviral Transfection of Chondrocyte-Seeded and Mesenchymal-Stem-Cell-Seeded Collagen Scaffolds.
June 16, 2010 at 6:35 AM
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| | Engineering Endostatin-Producing Cartilaginous Constructs for Cartilage Repair Using Nonviral Transfection of Chondrocyte-Seeded and Mesenchymal-Stem-Cell-Seeded Collagen Scaffolds. Tissue Eng Part A. 2010 Jun 14; Authors: Jeng L, Olsen BR, Spector M Although there is widespread recognition of the importance of angiogenesis in tissue repair, there is little work on the inhibition of angiogenesis in the context of tissue engineering of naturally avascular tissues, like articular cartilage. The objective was to engineer a collagen-scaffold-based cartilaginous construct overexpressing a potent antiangiogenic factor, endostatin, using nonviral transfection. Endostatin-plasmid-supplemented collagen scaffolds were seeded with mesenchymal stem cells and chondrocytes and cultured for 20-22 days. The effects of the following variables on endostatin expression and chondrogenesis were examined: collagen scaffold material, method of nonviral vector incorporation, plasmid load, culture medium, and oxygen tension. An increase and peak of endostatin protein was observed during the first week of culture, followed by a decrease to low levels, suggesting that overexpression of endostatin could be sustained for several days using the nonviral vector. The amount of endostatin produced was tunable with the external factors. Chondrogenesis was observed in the engineered constructs cultured in chondrogenic medium at the 3-week time point, demonstrating that endostatin did not inhibit the chondrogenic potential of mesenchymal stem cells or the general viability of the cells. The ability to engineer endostatin-expressing cartilaginous constructs will be of value for future work exercising regulatory control of angiogenesis in cartilage repair. PMID: 20545556 [PubMed - as supplied by publisher] | | |
| ENGINEERED BONE BY AUTOLOGOUS OSTEOBLASTS ON POLIMERIC SCAFFOLDS IN MAXILLARY SINUS AUGMENTATION: HISTOLOGICAL REPORT.
June 16, 2010 at 6:35 AM
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| | ENGINEERED BONE BY AUTOLOGOUS OSTEOBLASTS ON POLIMERIC SCAFFOLDS IN MAXILLARY SINUS AUGMENTATION: HISTOLOGICAL REPORT. J Oral Implantol. 2010 Jun 14; Authors: Mangano C, Piattelli A, Mangano F, Borges F, Iezzi G, Mangano A, d'Avila S, Tettamanti LT, Shibli J Abstract Several regenerative therapies have been used for maxillary sinus grafting. However, recent advances in Modern Bone Tissue Engineering techniques have been evaluated. The aim of this histological report was to evaluate the bone obtained by a culture of autogenous osteoblasts seeded on polyglycolic-polylactid scaffolds in maxillary sinus augmentation. A 56-year-old partially edentulous male with severe atrophy of the posterior maxilla received 6 polyglycolid-polylactid disks (8 mm diameter x 2mm depth, OralboneR, Biotissue, Freiburg, Germany), each carrying 1.5 million autogenous osteoblasts into the depth of the sinus cavity. After 6 months healing, a bone core was harvested and histologically evaluated. The augmented maxillary sinus with bone engineered presented a mean of 28.89% and 71.11% of bone and medullar spaces, respectively. Data from this case report demonstrates that the newly formed bone provided by bone tissue engineered allowed a proper initial stability to dental implant placement. However, the role of this new bone in the long-term success of dental implants anchorage needs further investigation. PMID: 20545540 [PubMed - as supplied by publisher] | | |
| Cell culture platform with mechanical conditioning and nondamaging cellular detachment.
June 16, 2010 at 6:35 AM
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| | Cell culture platform with mechanical conditioning and nondamaging cellular detachment. J Biomed Mater Res A. 2010 May;93(2):411-8 Authors: Lee EL, von Recum HA Cells implanted after injury may remodel undesirably with improper mechanical stimulation from surrounding tissue. Proper conditioning of tissue engineered constructs before implantation can lead to suitable tissue architectures, along with an extracellular matrix (ECM) environment that more closely mimics native tissue. Additionally, cell implantation without bulky polymeric scaffolding is often desirable. Previous researchers have created devices capable of applying mechanical forces to cells (e.g., stretch) but cellular removal from these devices, such as by trypsin, often results in irreversible damage. Conversely, devices are available that can detach intact cells, but these are inelastic, nonstretchable substrates. We have created a cell culture platform that allows for mechanical conditioning and then subsequent nondamaging detachment of those cells. We have modified silicone culture surfaces, to incorporate thermally responsive polymers of N-isopropylacrylamide (NIPAAm) to create an elastic substrate that can also change surface properties with temperature change. A copolymer of NIPAAm and 10percent w/w acrylic acid (AAc) was conjugated to an amine-bonded silicone surface through carbodiimide chemistry. Cells were able to attach to the resulting surfaces at 37 degreeC and showed detachment by rounded morphology at 25degreeC. Following mechanical stretching, cells were still able to spontaneously detach from these modified silicone surfaces with temperature change. PMID: 20358641 [PubMed - indexed for MEDLINE] | | |
| The use of flow perfusion culture and subcutaneous implantation with fibroblast-seeded PLLA-collagen 3D scaffolds for abdominal wall repair.
June 16, 2010 at 6:35 AM
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| | The use of flow perfusion culture and subcutaneous implantation with fibroblast-seeded PLLA-collagen 3D scaffolds for abdominal wall repair. Biomaterials. 2010 May;31(15):4330-40 Authors: Pu F, Rhodes NP, Bayon Y, Chen R, Brans G, Benne R, Hunt JA Highly cellularised 3D-tissue constructs designed to repair large, complex abdominal wall defects were prepared using poly (lactic acid) (PLLA)-collagen scaffolds in vitro using a flow perfusion bioreactor. The PLLA-collagen scaffolds had a unique structure consisting of a collagen sponge formed within the pores of a mechanically stable knitted mesh of PLLA. The effect of the flow perfusion bioreactor culturing conditions was investigated in vitro for 0, 7, 14 and 28 days on scaffolds seeded with dermal fibroblasts. The cultured constructs were subsequently studied subcutaneously (SC) in an in vivo animal model. The results of in vitro studies demonstrated that the perfusion system facilitated increased cell proliferation and homogenous distribution in the PLLA-collagen scaffolds compared to static conditions. A highly cellularised 3D-tissue construct was formed by 7 days incubation under perfusion conditions, with increased cellularity by the 28 day time point. The in vivo model demonstrated that implanting constructs with high cellularity resulted in exceptional cell stabilisation, with the survival of implanted cells and expression of the phenotypically-relevant extracellular matrix proteins collagen types I and III, studied by fluorescence in situ hybridisation (FISH) and immunohistochemistry. The implantation of this porous PPLA-collagen scaffold seeded with dermal fibroblasts following in vitro maturation using a flow perfusion bioreactor system suggests a significant advance over current state-of-the-art procedures for the reconstruction of large, complex abdominal wall tissue defects. PMID: 20219244 [PubMed - indexed for MEDLINE] | | |
| The role of three-dimensional polymeric scaffold configuration on the uniformity of connective tissue formation by adipose stromal cells.
June 16, 2010 at 6:35 AM
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| | The role of three-dimensional polymeric scaffold configuration on the uniformity of connective tissue formation by adipose stromal cells. Biomaterials. 2010 May;31(15):4322-9 Authors: Wang H, van Blitterswijk CA To form tissues with uniform cell distribution and extracellular matrix arrangement is of great relevance to obtain the desirable function and maintain structural integrity. Scaffold configuration is believed to play a critical role in regulating cell spatial distribution and consequently tissue formation. In this study, three types of poly(ethyleneglycol-terephthalate)-poly (butylenes terephthalate) (PEGT/PBT) scaffolds [compression molded scaffold (CM), compression molded scaffold after chloroform/isopropanol reticulation (CMR), 3D rapid prototyped fibrous scaffold (RP)] with various configurations were used to support the tissue formation of adipose stromal cells for up to 21 days. Characterization of the scaffolds with muCT revealed that RP scaffolds were composed of repeating structural units with well controlled interconnected pores, in contrast to the irregular pore morphology in CM or CMR. Cell seeding efficacy onto various scaffolds was comparable (from 67 +/- 4% to 82 +/- 3%), while only RP scaffold led to even cell attachment onto the inner fibers of the scaffolds. Continuous cell proliferation and deposition of new collagen and glycosaminoglycans (GAG) were measured for all three scaffolds, while with a significant amount measured in RP at 21 days. By 21 days, complete uniform tissue formation was only achieved in RP scaffolds under a dynamic cell culture in spinner flasks. The present study successfully demonstrates the feasibility of controlling uniform tissue formation at a microscale by manipulating the structural configuration of the scaffold. PMID: 20199809 [PubMed - indexed for MEDLINE] | | | | 
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