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| Immunosuppressive properties of human umbilical cord-derived mesenchymal stem cells: role of B7-H1 and IDO.
April 14, 2010 at 7:02 AM
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| | Immunosuppressive properties of human umbilical cord-derived mesenchymal stem cells: role of B7-H1 and IDO. Immunol Cell Biol. 2010 Apr 13; Authors: Tipnis S, Viswanathan C, Majumdar AS Umbilical cord is a rich source of mesenchymal stromal or stem cells (MSCs) that can be used for developing allogeneic cell therapy to treat intractable diseases. In this report, we present evidence that umbilical cord-derived MSCs (UCMSCs) possess important immunomodulatory properties that may enable them to survive in an allogeneic environment. UCMSCs do not express human leukocyte antigen (HLA)-DR and co-stimulatory molecules CD80 and CD86 that are required for T-cell activation. More importantly, UCMSCs constitutively express a negative regulator of T-cell activation, B7-H1, and its expression is increased after interferon-gamma (IFN-gamma) treatment. In addition, IFN-gamma treatment induced indoleamine 2,3-dioxygenase (IDO) and HLA-DR expression in UCMSCs. Neither control nor IFN-gamma-treated UCMSCs stimulated allogeneic T-cell proliferation, and both cell populations inhibited third-party dendritic cell (DC)-mediated allostimulatory activity. Addition of a ! B7-H1-specific blocking antibody or an IDO inhibitor, 1 methyl tryptophan (1-MT) abrogated the T-cell immunosuppressive activity of these cells. Furthermore, UCMSCs prevented the differentiation and maturation of peripheral blood monocyte-derived DCs, and augmented the generation of regulatory T cells (Tregs) in culture. The immunosuppressive effects of UCMSCs are largely mediated by cell-to-cell contact, although some inhibitory activity was observed with cell-free supernatant. Our study suggests that these immunomodulatory properties of UCMSCs could potentially improve the outcome of allogeneic stem cell therapy.Immunology and Cell Biology advance online publication, 13 April 2010; doi:10.1038/icb.2010.47. PMID: 20386557 [PubMed - as supplied by publisher] | | |
| Mesenchymal stem cell therapy for the treatment of chronic obstructive pulmonary disease.
April 14, 2010 at 7:02 AM
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| | Mesenchymal stem cell therapy for the treatment of chronic obstructive pulmonary disease. Expert Opin Biol Ther. 2010 May;10(5):681-7 Authors: D'Agostino B, Sullo N, Siniscalco D, De Angelis A, Rossi F Recent studies have revealed that adult stem cells such as bone marrow-derived cells contribute to lung tissue regeneration and protection, and thus administration of exogenous stem/progenitor cells may be a potent next-generation therapy for COPD. Pathogenesis of COPD is characterized by an upregulation of inflammatory processes leading to irreversible events such as apoptosis of epithelial cells, proteolysis of the terminal air-space and lung extracellular matrix components. The available pharmacological treatments are essentially symptomatic, therefore, there is a need to develop more effective therapeutic strategies. It has been previously demonstrated that transplanted MSC home to the lung in response to lung injury and adopt phenotypes of alveolar epithelial cells, endothelial cells, fibroblasts and bronchial epithelial cells. However, engraftment and differentiation are now felt to be rare occurrences and other mechanisms might be involved and play a more i! mportant role. Importantly, MSCs protect lung tissue through suppression of proinflammatory cytokines, and through triggering production of reparative growth factors. Accordingly, it is not clear if and how these cells will be able to repair, to slow or to prevent the disease. This article reviews recent advances in regenerative medicine in COPD and highlights that their potential application although promising and very attractive, are still a far away opinion. PMID: 20384521 [PubMed - in process] | | |
| Effects of Pulsed Electromagnetic Fields on Human Osteoblastlike Cells (MG-63): A Pilot Study.
April 14, 2010 at 6:59 AM
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| | Effects of Pulsed Electromagnetic Fields on Human Osteoblastlike Cells (MG-63): A Pilot Study. Clin Orthop Relat Res. 2010 Apr 13; Authors: Sollazzo V, Palmieri A, Pezzetti F, Massari L, Carinci F BACKGROUND: Although pulsed electromagnetic fields (PEMFs) are used to treat delayed unions and nonunions, their mechanisms of action are not completely clear. However, PEMFs are known to affect the expression of certain genes. QUESTIONS/PURPOSES: We asked (1) whether PEMFs affect gene expression in human osteoblastlike cells (MG63) in vitro, and (2) whether and to what extent stimulation by PEMFs induce cell proliferation and differentiation in MG-63 cultures. METHODS: We cultured two groups of MG63 cells. One group was treated with PEMFs for 18 hours whereas the second was maintained in the same culture condition without PEMFs (control). Gene expression was evaluated throughout cDNA microarray analysis containing 19,000 genes spanning a substantial fraction of the human genome. RESULTS: PEMFs induced the upregulation of important genes related to bone formation (HOXA10, AKT1), genes at the transductional level (CALM1, P2RX7), genes for cytoskeletal components (F! N1, VCL), and collagenous (COL1A2) and noncollagenous (SPARC) matrix components. However, PEMF induced downregulation of genes related to the degradation of extracellular matrix (MMP-11, DUSP4). CONCLUSIONS AND CLINICAL RELEVANCE: PEMFs appear to induce cell proliferation and differentiation. Furthermore, PEMFs promote extracellular matrix production and mineralization while decreasing matrix degradation and absorption. Our data suggest specific mechanisms of the observed clinical effect of PEMFs, and thus specific approaches for use in regenerative medicine. PMID: 20387020 [PubMed - as supplied by publisher] | | |
| Immunosuppressive properties of human umbilical cord-derived mesenchymal stem cells: role of B7-H1 and IDO.
April 14, 2010 at 6:59 AM
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| | Immunosuppressive properties of human umbilical cord-derived mesenchymal stem cells: role of B7-H1 and IDO. Immunol Cell Biol. 2010 Apr 13; Authors: Tipnis S, Viswanathan C, Majumdar AS Umbilical cord is a rich source of mesenchymal stromal or stem cells (MSCs) that can be used for developing allogeneic cell therapy to treat intractable diseases. In this report, we present evidence that umbilical cord-derived MSCs (UCMSCs) possess important immunomodulatory properties that may enable them to survive in an allogeneic environment. UCMSCs do not express human leukocyte antigen (HLA)-DR and co-stimulatory molecules CD80 and CD86 that are required for T-cell activation. More importantly, UCMSCs constitutively express a negative regulator of T-cell activation, B7-H1, and its expression is increased after interferon-gamma (IFN-gamma) treatment. In addition, IFN-gamma treatment induced indoleamine 2,3-dioxygenase (IDO) and HLA-DR expression in UCMSCs. Neither control nor IFN-gamma-treated UCMSCs stimulated allogeneic T-cell proliferation, and both cell populations inhibited third-party dendritic cell (DC)-mediated allostimulatory activity. Addition of a ! B7-H1-specific blocking antibody or an IDO inhibitor, 1 methyl tryptophan (1-MT) abrogated the T-cell immunosuppressive activity of these cells. Furthermore, UCMSCs prevented the differentiation and maturation of peripheral blood monocyte-derived DCs, and augmented the generation of regulatory T cells (Tregs) in culture. The immunosuppressive effects of UCMSCs are largely mediated by cell-to-cell contact, although some inhibitory activity was observed with cell-free supernatant. Our study suggests that these immunomodulatory properties of UCMSCs could potentially improve the outcome of allogeneic stem cell therapy.Immunology and Cell Biology advance online publication, 13 April 2010; doi:10.1038/icb.2010.47. PMID: 20386557 [PubMed - as supplied by publisher] | | |
| Increasing Long-Term Major Vascular Events and Resource Consumption in Patients Receiving Off-Pump Coronary Artery Bypass. A Single-Center Prospective Observational Study.
April 14, 2010 at 6:59 AM
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| | Increasing Long-Term Major Vascular Events and Resource Consumption in Patients Receiving Off-Pump Coronary Artery Bypass. A Single-Center Prospective Observational Study. Circulation. 2010 Apr 12; Authors: Hu S, Zheng Z, Yuan X, Wang W, Song Y, Sun H, Xu J BACKGROUND: -Despite its widespread use and short-term efficacy, substantial uncertainty remains about the long-term outcomes and cost-effectiveness of off-pump coronary artery bypass (OPCAB). Methods and Results-A retrospective review of prospectively collected data was conducted of 6665 consecutive patients undergoing isolated coronary artery bypass graft (CABG) at our institution during 1999 to 2006. All patients were followed up until September 30, 2008. Short- and long-term outcomes were compared between OPCAB and conventional CABG. The 2 main long-term outcome measures were repeat revascularization and the composite outcome of major vascular events. Cost comparison at 2 years in a propensity-matched sample during follow-up was also a study interest. The overall mean baseline age was 60.3+/-8.6 years, and 17.0% were women. Compared with conventional CABG, patients who underwent OPCAB had lower rates of atrial fibrillation (P=0.003) and requirements for blood ! transfusion (P=0.03) and ventilation time >24 hours (P<0.001). After an average of 4.5 years of follow-up, the rates of repeat revascularization (adjusted hazard ratio, 1.40; 95% confidence interval, 1.03 to 1.89) and major vascular events (adjusted hazard ratio, 1.23; 95% confidence interval, 1.09 to 1.39) were significantly higher in the OPCAB than the conventional CABG group. At 2 years, OPCAB was associated with increased additional direct costs per patient compared with conventional CABG and had a similar survival rate. Conclusions-Compared with conventional CABG, OPCAB is associated with small short-term gain but increased long-term risks of repeat revascularization and major vascular events, especially among high-risk patients. Moreover, OPCAB consumes more resources and is less cost-effective in the long run. PMID: 20385931 [PubMed - as supplied by publisher] | | |
| A Pivotal Role for PINK1 and Autophagy in Mitochondrial Quality Control: Implications for Parkinson Disease.
April 14, 2010 at 6:59 AM
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| | A Pivotal Role for PINK1 and Autophagy in Mitochondrial Quality Control: Implications for Parkinson Disease. Hum Mol Genet. 2010 Apr 12; Authors: Chu CT The PTEN induced putative kinase 1 (PINK1) is a mitochondrially targeted serine-threonine kinase, which is linked to autosomal recessive familial parkinsonism. Current literature implicates PINK1 as a pivotal regulator of mitochondrial quality control, promoting maintenance of respiring mitochondrial networks through cristae stabilization, phosphorylation of chaperones, and possibly regulation of mitochondrial transport or autophagy. Pulse chase studies indicate that PINK1 is rapidly processed into at least two shorter forms, which are distributed in both mitochondrial and cytosolic compartments. Through indirect regulation of mitochondrial proteases and Drp1, PINK1 may act to facilitate localized repair and fusion in response to minor mitochondrial stress. With severe mitochondrial damage, PINK1 facilitates aggregation and clearance of depolarized mitochondria through interactions with Parkin and possibly Beclin1. This switch in function most likely involves alte! red processing, post-translational modification and/or localization of PINK1, as overexpression of full length PINK1 is required for mitochondrial Parkin recruitment. Under conditions of PINK1 deficiency, dysregulation of reactive oxygen species, electron transport chain function and calcium homeostasis trigger altered mitochondrial dynamics, indicating compromise of mitochondrial quality control mechanisms. Nevertheless, Parkin- and Beclin1-regulated autophagy remains effective at recycling PINK1-deficient mitochondria; failure of this final tier of mitochondrial quality control contributes to cell death. Thus, PINK1 plays a pivotal, multifactorial role in mitochondrial homeostasis. As autophagic recycling represents the final tier of mitochondrial quality control, under conditions where PINK1 levels are either enhanced or reduced, strategies to promote selective mitophagy and mitochondrial biogenesis may prove effective for multiple forms of Parkinson's disease. PMID: 20385539 [PubMed - as supplied by publisher] | | |
| ES and iPS cell research for cardiovascular regeneration.
April 14, 2010 at 6:59 AM
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| | ES and iPS cell research for cardiovascular regeneration. Exp Cell Res. 2010 Apr 9; Authors: Yamashita JK Embryonic stem (ES) cells and induced pluripotent stem (iPS) cells, which are ES-like stem cells induced from adult tissues, are twin stem cells with currently (with the exception of fertilized eggs) the broadest differentiation potentials. These two stem cells show various similarities in appearance, maintenance methods, growth and differentiation potentials, i.e. theoretically, those cells can give rise to all kinds of cells including germ-line cells. Generation of human ES and iPS cells is further facilitating the researches towards the realization of regenerative medicine. The following three issues are important purposes of ES and iPS cell researches for regenerative medicine: 1) Dissection of differentiation mechanisms, 2) Application to cell transplantation, and 3) Drug discovery. In this review, the current status of cardiovascular regenerative trials using ES and iPS cells is briefly discussed. PMID: 20385126 [PubMed - as supplied by publisher] | | |
| Mesenchymal stem cell therapy for the treatment of chronic obstructive pulmonary disease.
April 14, 2010 at 6:59 AM
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| | Mesenchymal stem cell therapy for the treatment of chronic obstructive pulmonary disease. Expert Opin Biol Ther. 2010 May;10(5):681-7 Authors: D'Agostino B, Sullo N, Siniscalco D, De Angelis A, Rossi F Recent studies have revealed that adult stem cells such as bone marrow-derived cells contribute to lung tissue regeneration and protection, and thus administration of exogenous stem/progenitor cells may be a potent next-generation therapy for COPD. Pathogenesis of COPD is characterized by an upregulation of inflammatory processes leading to irreversible events such as apoptosis of epithelial cells, proteolysis of the terminal air-space and lung extracellular matrix components. The available pharmacological treatments are essentially symptomatic, therefore, there is a need to develop more effective therapeutic strategies. It has been previously demonstrated that transplanted MSC home to the lung in response to lung injury and adopt phenotypes of alveolar epithelial cells, endothelial cells, fibroblasts and bronchial epithelial cells. However, engraftment and differentiation are now felt to be rare occurrences and other mechanisms might be involved and play a more i! mportant role. Importantly, MSCs protect lung tissue through suppression of proinflammatory cytokines, and through triggering production of reparative growth factors. Accordingly, it is not clear if and how these cells will be able to repair, to slow or to prevent the disease. This article reviews recent advances in regenerative medicine in COPD and highlights that their potential application although promising and very attractive, are still a far away opinion. PMID: 20384521 [PubMed - in process] | | |
| Cell microencapsulation.
April 14, 2010 at 6:59 AM
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| | Cell microencapsulation. Adv Exp Med Biol. 2010;670:126-36 Authors: Lim GJ, Zare S, Van Dyke M, Atala A In the past several decades, many attempts have been made to prevent the rejection of transplanted cells by the immune system. Cell encapsulation is primary machinery for cell transplantation and new materials and approaches were developed to encapsulate various types of cells to treat a wide range of diseases. This technology involves placing the transplanted cells within a biocompatible membrane in attempt to isolate the cells from the host immune attack and enhance or prolong their function in vivo. In this chapter, we will review the situation of cell microencapsulation field and discuss its potentials and challenges for cell therapy and regeneration of tissue function. PMID: 20384223 [PubMed - in process] | | |
| Artificial cell microencapsulated stem cells in regenerative medicine, tissue engineering and cell therapy.
April 14, 2010 at 6:59 AM
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| | Artificial cell microencapsulated stem cells in regenerative medicine, tissue engineering and cell therapy. Adv Exp Med Biol. 2010;670:68-79 Authors: Liu ZC, Chang TM Adult stem cells, especially isolated from bone marrow, have been extensively investigated in recent years. Studies focus on their multiple plasticity oftransdifferentiating into various cell lineages and on their potential in cellular therapy in regenerative medicine. In many cases, there is the need for tissue engineering manipulation. Among the different approaches of stem cells tissue engineering, microencapsulation can immobilize stem cells to provide a favorable microenvironment for stem cells survival and functioning. Furthermore, microencapsulated stem cells are immunoisolated after transplantation. We show that one intraperitoneal injection of microencapsulated bone marrow stem cells can prolong the survival of liver failure rat models with 90% of the liver removed surgically. In addition to transdifferentiation, bone marrow stem cells can act as feeder cells. For example, when coencapsulated with hepatocytes, stem cells can increase the viability and fun! ction of the hepatocytes in vitro and in vivo. PMID: 20384219 [PubMed - in process] | | |
| Cell Attachment-Detachment Control on Temperature-Responsive Thin Surfaces for Novel Tissue Engineering.
April 14, 2010 at 6:56 AM
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| | Cell Attachment-Detachment Control on Temperature-Responsive Thin Surfaces for Novel Tissue Engineering. Ann Biomed Eng. 2010 Apr 13; Authors: Kumashiro Y, Yamato M, Okano T Temperature-responsive intelligent surfaces, prepared by the modification of an interface mainly with poly(N-isopropylacrylamide) and its derivatives, have been investigated. Such surfaces exhibit temperature-responsive hydrophilic/hydrophobic alterations with external temperature changes, which, in turn, result in thermally modulated attachment and detachment with cells. The advantage of this system is that cells cultured on such temperature-responsive surfaces can be recovered as single cells and/or confluent cell sheets, while keeping the deposited extracellular matrix intact, simply by lowering the temperature without conventional enzymatic treatment. Here, we focus and compare various methods of producing temperature-responsive surfaces for controlling cell attachment/detachment. Spontaneous cell attachment and detachment using several types of temperature-responsive surfaces are mentioned and various effects, such as film thickness and polymer conformation, ! are discussed. In addition, the development of the next generation of temperature-responsive surfaces using modifications of the polymer coating to allow for rapid cell recovery is summarized. PMID: 20387117 [PubMed - as supplied by publisher] | | |
| Extensive adipogenic and osteogenic differentiation of patterned human mesenchymal stem cells in a microfluidic device.
April 14, 2010 at 6:56 AM
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| | Extensive adipogenic and osteogenic differentiation of patterned human mesenchymal stem cells in a microfluidic device. Lab Chip. 2010 Mar 9; Authors: Tenstad E, Tourovskaia A, Folch A, Myklebost O, Rian E Microtechnology offers great prospects for cellular research by enabling controlled experimental conditions that cannot be achieved by traditional methods. This study demonstrates the use of a microfluidic platform for long-term cultivation (3 weeks) of human mesenchymal stem-like cells (MSCs), a cell population of high interest for tissue engineering. The typical high motility of the MSCs required a strategy for preventing cells from inhabiting the feeding channels and thus interfere with a steady perfusion of medium to the cell cultivation chamber. Hence, a straightforward and long-term patterning method was developed and implemented for reliable cell positioning within the device. This method was based on the modification of a polystyrene substrate into cell supportive and non-supportive regions by the use of selective oxygen plasma treatment and the triblock copolymer Pluronic. Also, a novel and size-effective "flip-chip" set-up for operating the devices was i! nvented. Successful and reproducible adipogenic and osteogenic differentiation of MSCs in the device was demonstrated, verifying that an adequate long-term microfluidic cultivation environment was obtained. Strengths of the experimental protocol include ease of fabrication and maintenance (gravity driven), good cell performance (viability/differentiation), as well as the possibility of exposing the culture to heterogeneous laminar flow for experimental purposes. PMID: 20386793 [PubMed - as supplied by publisher] | | |
| Influence of Cell-Adhesive Peptide Ligands on Poly(ethylene glycol) Hydrogel Physical, Mechanical and Transport Properties.
April 14, 2010 at 6:56 AM
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| | Influence of Cell-Adhesive Peptide Ligands on Poly(ethylene glycol) Hydrogel Physical, Mechanical and Transport Properties. Acta Biomater. 2010 Apr 9; Authors: Zustiak SP, Durbal R, Leach JB Synthetic three-dimensional (3D) scaffolds for cell and tissue engineering routinely utilize peptide ligands to provide sites for cell adhesion and to promote cellular activity. Given the fact that recent studies have dedicated great attention to the mechanisms by which cell behavior is influenced by various ligands and scaffold material properties, it is surprising that little work to date has been carried out to investigate the influence of covalently-bound ligands on hydrogel material properties. Herein we report the influence of 3 common ligands utilized in tissue engineering, namely RGD, YIGSR, and IKVAV on the mechanical properties of cross-linked poly(ethylene glycol) (PEG) hydrogels. The effect of the ligands on hydrogel storage modulus, swelling ratio, mesh size, and also on the diffusivity of bovine serum albumin (BSA) through the hydrogel were investigated in detail. We identified conditions at which these ligands strikingly influence the properties of ! the material: the extent of influence and whether the ligand increases or decreases a specific property is linked to ligand type and concentration. Further, we pinpoint mechanisms by which the ligands interact with the PEG network. This work thus provides specific evidence for interactions between peptide ligands and cross-linked PEG hydrogels that significantly impact hydrogel material and transport properties. As a result, this work may have important implications for interpreting cell experiments carried out with ligand-modified hydrogels because the addition of ligand may affect not only the scaffold's biological properties, but also key physical properties of the system. PMID: 20385260 [PubMed - as supplied by publisher] | | |
| Applications of elastin-like polypeptides in tissue engineering.
April 14, 2010 at 6:56 AM
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| | Applications of elastin-like polypeptides in tissue engineering. Adv Drug Deliv Rev. 2010 Apr 9; Authors: Nettles DL, Chilkoti A, Setton LA Elastin-like polypeptides (ELPs) have found utility in tissue engineering applications, not only because they are biocompatible, biodegradable, and non-immunogenic, but also because their amino acid sequence and molecular weight can be precisely controlled at the genetic or synthetic level, affording exquisite control over final protein functionality. This review presents a basic overview of ELP properties and modifications that are relevant to tissue engineering, as well as a discussion of the application of ELPs to cartilage, intervertebral disc, vascular graft, liver, ocular, and cell sheet engineering. PMID: 20385185 [PubMed - as supplied by publisher] | | |
| Artificial cell microencapsulated stem cells in regenerative medicine, tissue engineering and cell therapy.
April 14, 2010 at 6:56 AM
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| | Artificial cell microencapsulated stem cells in regenerative medicine, tissue engineering and cell therapy. Adv Exp Med Biol. 2010;670:68-79 Authors: Liu ZC, Chang TM Adult stem cells, especially isolated from bone marrow, have been extensively investigated in recent years. Studies focus on their multiple plasticity oftransdifferentiating into various cell lineages and on their potential in cellular therapy in regenerative medicine. In many cases, there is the need for tissue engineering manipulation. Among the different approaches of stem cells tissue engineering, microencapsulation can immobilize stem cells to provide a favorable microenvironment for stem cells survival and functioning. Furthermore, microencapsulated stem cells are immunoisolated after transplantation. We show that one intraperitoneal injection of microencapsulated bone marrow stem cells can prolong the survival of liver failure rat models with 90% of the liver removed surgically. In addition to transdifferentiation, bone marrow stem cells can act as feeder cells. For example, when coencapsulated with hepatocytes, stem cells can increase the viability and fun! ction of the hepatocytes in vitro and in vivo. PMID: 20384219 [PubMed - in process] | | |
| Construction and clinical application of a human tissue-engineered epidermal membrane.
April 14, 2010 at 6:56 AM
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| | Construction and clinical application of a human tissue-engineered epidermal membrane. Plast Reconstr Surg. 2010 Mar;125(3):901-9 Authors: Yang J, Woo SL, Yang G, Wang J, Cui L, Liu W, Cao Y BACKGROUND: Prolonged healing times and hypertrophic scarring of the donor site for split-thickness-skin grafts thicker than 0.3 mm are common problems that continue to challenge plastic surgeons in the clinic. As such, a human tissue-engineered epidermal membrane was constructed to promote wound healing and reduce scar hypertrophy. METHODS: An artificial allogenic epidermis was created in vitro using human keratinocytes and chitosan-gelatin membrane. Split-thickness skin graft donor sites were divided into three treatment groups: those covered with the combined keratinocyte/chitosan-gelatin membrane, those covered with chitosan-gelatin membrane only (control group), and those covered with traditional petroleum jelly gauze (blank group). The degree of wound healing was assessed at various time points after the operation by gross observation, hematoxylin and eosin staining, immunohistochemistry, and an assay of type I collagen using the picrosirius polarization met! hod. Reverse-transcriptase polymerase chain reaction detection of the Y chromosome was also performed to distinguish between sexes. RESULTS: Over a 6-month observation period, treatment with the human tissue-engineered epidermal membrane (keratinocyte/chitosan-gelatin) appeared to decrease donor-site healing time (48 wounds in 24 cases). Average healing time was 8.1 +/- 1.3 days for the keratinocyte/chitosan-gelatin group, 16.4 +/- 1.7 days for the chitosan-gelatin group, and 22.9 +/- 4.2 days for the blank group. The artificial epidermis survived well and maintained a normal structure. Furthermore, hypertrophic scar formation was less severe for these wounds. CONCLUSIONS: Keratinocyte/chitosan-gelatin membranes can be constructed in vitro and survive temporarily in vivo. They can be used to promote wound healing and reduce the severity of hypertrophic scarring of skin graft donor sites. PMID: 20009787 [PubMed - indexed for MEDLINE] | | |
| Engineering cartilage substitute with a specific size and shape using porous high-density polyethylene (HDPE) as internal support.
April 14, 2010 at 6:56 AM
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| | Engineering cartilage substitute with a specific size and shape using porous high-density polyethylene (HDPE) as internal support. J Plast Reconstr Aesthet Surg. 2010 Apr;63(4):e370-5 Authors: Wu Y, Zhu L, Jiang H, Liu W, Liu Y, Cao Y, Zhou G Despite the great advances in cartilage engineering, constructing cartilage of large sizes and appropriate shapes remains a great challenge, owing to limits in thickness of regenerated cartilage and to inferior mechanical properties of scaffolds. This study introduces a pre-shaped polyglycolic acid (PGA)-coated porous high-density polyethylene (HDPE) scaffold to overcome these challenges. HDPE was carved into cylindrical rods and wrapped around by PGA fibres to form PGA-HDPE scaffolds. Porcine chondrocytes were seeded into the scaffolds and the constructs were cultured in vitro for 2 weeks before subcutaneous implantation into nude mice. Scaffolds made purely of PGA with the same size and shape were used as a control. After 8 weeks of implantation, the construct formed cartilage-like tissue and retained its pre-designed shape and size. In addition, the regenerated cartilage grew and completely surrounded the HDPE core, which made the entire cartilage substitute bi! ocompatible to its implanted environment as native cartilage similarly does. By contrast, the shape and size of the constructs in the control group seriously deformed and obvious hollow cavity and necrotic tissue were observed in the inner region. These results demonstrate that the use of HDPE as the internal support of a biodegradable scaffold has the potential to circumvent the problems of limitations in size and shape, with promising implications for the development of engineered cartilage appropriate for clinical applications. PMID: 19945928 [PubMed - indexed for MEDLINE] | | |
| Repair of large osteochondral defects in rabbits using porous hydroxyapatite/collagen (HAp/Col) and fibroblast growth factor-2 (FGF-2).
April 14, 2010 at 6:56 AM
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| | Repair of large osteochondral defects in rabbits using porous hydroxyapatite/collagen (HAp/Col) and fibroblast growth factor-2 (FGF-2). J Orthop Res. 2010 May;28(5):677-86 Authors: Maehara H, Sotome S, Yoshii T, Torigoe I, Kawasaki Y, Sugata Y, Yuasa M, Hirano M, Mochizuki N, Kikuchi M, Shinomiya K, Okawa A Articular cartilage has a limited capacity for self-renewal. This article reports the development of a porous hydroxyapatite/collagen (HAp/Col) scaffold as a bone void filler and a vehicle for drug administration. The scaffold consists of HAp nanocrystals and type I atelocollagen. The purpose of this study was to investigate the efficacy of porous HAp/Col impregnated with FGF-2 to repair large osteochondral defects in a rabbit model. Ninety-six cylindrical osteochondral defects 5 mm in diameter and 5 mm in depth were created in the femoral trochlear groove of the right knee. Animals were assigned to one of four treatment groups: porous HAp/Col impregnated with 50 microl of FGF-2 at a concentration of 10 or 100 microg/ml (FGF10 or FGF100 group); porous HAp/Col with 50 microl of PBS (HAp/Col group); and no implantation (defect group). The defect areas were examined grossly and histologically. Subchondral bone regeneration was quantified 3, 6, 12, and 24 weeks after ! surgery. Abundant bone formation was observed in the HAp/Col implanted groups as compared to the defect group. The FGF10 group displayed not only the most abundant bone regeneration but also the most satisfactory cartilage regeneration, with cartilage presenting a hyaline-like appearance. These findings suggest that porous HAp/Col with FGF-2 augments the cartilage repair process. PMID: 19918893 [PubMed - indexed for MEDLINE] | | | | 
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