| Osteogenic differentiation of human mesenchymal stromal cells is promoted by a leukocytes containing fibrin matrix.
January 21, 2010 at 9:52 AM
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| | Osteogenic differentiation of human mesenchymal stromal cells is promoted by a leukocytes containing fibrin matrix. Langenbecks Arch Surg. 2010 Jan 20; Authors: Seybold D, Schildhauer TA, Geßmann J, Muhr G, Köller M, Roetman B PURPOSE: Mesenchymal stem cells (multipotent human mesenchymal stromal cells, MSC) are currently the most promising cell type for regenerative medicine. For a clinical approach, it is necessary to develop and establish methods for expansion, differentiation, and delivery. METHODS: A completely autologous plasma clot containing peripheral blood mononuclear cells (PBMC) was tested for the osteopromotive activity towards expanded human mesenchymal stem cells in vitro. The plasma clot was prepared from anticoagulated blood plasma after addition of isolated leukocytes and calcium chloride. Plasma clots after the gelation were added to subconfluently growing MSC or used in a transwell system. Cell proliferation, the activity of alkaline phosphatase, the release of osteoprotegerin, C-terminal procollagen peptide, as well as osteocalcin, the analysis of matrix mineralization as well as bone nodule formation were analyzed up to 3 weeks. RESULTS: In contrast to plasma clots! with no exogenously added leukocytes, the presence of PBMC within the plasma clot significantly promoted osteogenic differentiation of MSC correlated to the time period of incubation. Proliferation of MSC was decreased at maximal mineralization time points. In addition, the osteopromotive activity was identified as soluble factor/factors by transwell assay system. There was a decrease in osteoprotegerin when the cells were cultured in the presence of plasma clots compared to control cell cultures without plasma clots. The osteocalcin expression was continuously higher after culture in the presence of plasma clots and significantly higher after 2- and 3-week after culture in the presence of leukocyte-containing plasma clots compared to 1-week cell culture. Differences in the concentration of the C-terminal procollagen peptide were not measured. CONCLUSIONS: The direct inoculation of an autologous mononuclear cell fraction (which contains leukocytes and MSC), e.g., isolated ! from a bone marrow aspirate or a different source into an auto! logous p lasma gel, may be a further new strategy for bone fracture therapy. PMID: 20087746 [PubMed - as supplied by publisher] | | |
| Nanotechnology-based manipulation of dendritic cells for enhanced immunotherapy strategies.
January 21, 2010 at 9:52 AM
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| | Nanotechnology-based manipulation of dendritic cells for enhanced immunotherapy strategies. Nanomedicine. 2010 Jan 16; Authors: Klippstein R, Pozo D Dendritic cells (DCs) are potent antigen presenting cells capable of initiating a primary immune response and possess the ability to activate T cells and stimulate the growth and differentiation of B cells. DCs provide a direct connection between innate and adaptive immune response and arise from bone marrow precursors that are present in immature forms in peripheral tissues where they are prepared to capture antigens. DCs migrate from the peripheral tissues to the closest lymph nodes through afferent lymphatic vessels to present the foreign antigens, stimulating T cell activation and initiating a cellular immune response. Moreover, it is known that DCs play an important role in various diseases and conditions where the immune system is involved, particularly in cancer and autoimmune disorders. For this reasons, targeting nanoparticles (NPs) to DCs provides a promising strategy for developing an efficient balanced and protective immune response. NPs can modulate t! he immune response and might be potentially useful as effective vaccine adjuvants for infectious disease and cancer therapy. The objective of this review is to present the latest advances in nanoparticle delivery methods targeting DCs, the mechanisms of action, potential effects, and therapeutic results of these systems and their future applications, such as improved vaccination strategies, cancer immunotherapy, and immunomodulatory treatments. PMID: 20085824 [PubMed - as supplied by publisher] | | |
| Human Embryonic Stem Cell-Derived Keratinocytes: How Close to Clinics?
January 21, 2010 at 9:52 AM
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| | Human Embryonic Stem Cell-Derived Keratinocytes: How Close to Clinics? Cell Stem Cell. 2010 Jan 8;6(1):8-9 Authors: Pellegrini G, De Luca M Recently in The Lancet, Guenou et al. (2009) demonstrate that human embryonic stem cells (hESCs) can differentiate into mature keratinocytes able to generate a pluristratified epithelium on immunodeficient mice. Their findings and the potential clinical use of hESC-derived keratinocytes will be discussed. PMID: 20085737 [PubMed - as supplied by publisher] | | |
| Ductal Origin Hypothesis of Pancreatic Regeneration under Attack.
January 21, 2010 at 9:52 AM
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| | Ductal Origin Hypothesis of Pancreatic Regeneration under Attack. Cell Metab. 2010 Jan 6;11(1):2-3 Authors: Kushner JA, Weir GC, Bonner-Weir S Although pancreatic beta cells are known to expand by self-renewal in postnatal life, contribution by ductal progenitors remains vigorously debated. In a recent issue of Developmental Cell, Jorge Ferrer and colleagues report lineage tracing studies that challenge the ductal origin hypothesis (Solar et al., 2009). PMID: 20085728 [PubMed - as supplied by publisher] | | |
| Cell Seeding Techniques in Vascular Tissue Engineering.
January 21, 2010 at 9:52 AM
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| | Cell Seeding Techniques in Vascular Tissue Engineering. Tissue Eng Part B Rev. 2010 Jan 19; Authors: Villalona GA, Udelsman B, Duncan DR, McGillicuddy E, Sawh-Martinez R, Mirensky T, Hibino N, Painter C, Erickson B, Shinoka T, Breuer C Previous studies have demonstrated the benefits of cell seeding in the construction of tissue engineered vascular grafts. Seeding methods are diverse, however, and no method is clearly superior in promoting seeding efficiency and the rapid development of a neovessel that mimics native vessels in form and function. Because seeded grafts hold great promise for advancing the field of vascular tissue engineering, a consensus should be developed regarding optimal seeding techniques. In this review, we summarize important advances in the field of vascular tissue engineering, focusing particular attention on cell seeding techniques in tissue engineered vascular graft development. PMID: 20085439 [PubMed - as supplied by publisher] | | |
| Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells.
January 21, 2010 at 9:52 AM
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| | Repairing skeletal muscle: regenerative potential of skeletal muscle stem cells. J Clin Invest. 2010 Jan;120(1):11-9 Authors: Tedesco FS, Dellavalle A, Diaz-Manera J, Messina G, Cossu G Skeletal muscle damaged by injury or by degenerative diseases such as muscular dystrophy is able to regenerate new muscle fibers. Regeneration mainly depends upon satellite cells, myogenic progenitors localized between the basal lamina and the muscle fiber membrane. However, other cell types outside the basal lamina, such as pericytes, also have myogenic potency. Here, we discuss the main properties of satellite cells and other myogenic progenitors as well as recent efforts to obtain myogenic cells from pluripotent stem cells for patient-tailored cell therapy. Clinical trials utilizing these cells to treat muscular dystrophies, heart failure, and stress urinary incontinence are also briefly outlined. PMID: 20051632 [PubMed - indexed for MEDLINE] | | |
| Stem cells: roadmap to the clinic.
January 21, 2010 at 9:52 AM
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| | Stem cells: roadmap to the clinic. J Clin Invest. 2010 Jan;120(1):8-10 Authors: Daley GQ Over the last decade, a remarkable number of papers have been published in which the biology of stem cells is introduced with words and phrases such as "promise," "rapid progress," and "future therapies." To separate myth and hype from reality, the articles in this Stem Cells Review series comprise a rich resource on the state of this fast-paced field and provide a balanced perspective on some of the major advances. They recount what the field has achieved over the past decade and where the field is headed. They also highlight the challenges to be faced in translating what is indeed highly promising science into proven therapies that will regenerate and repair diseased tissues. PMID: 20051631 [PubMed - indexed for MEDLINE] | | |
| IL-17 produced by neutrophils regulates IFN-gamma-mediated neutrophil migration in mouse kidney ischemia-reperfusion injury.
January 21, 2010 at 9:52 AM
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| | IL-17 produced by neutrophils regulates IFN-gamma-mediated neutrophil migration in mouse kidney ischemia-reperfusion injury. J Clin Invest. 2010 Jan;120(1):331-42 Authors: Li L, Huang L, Vergis AL, Ye H, Bajwa A, Narayan V, Strieter RM, Rosin DL, Okusa MD The IL-23/IL-17 and IL-12/IFN-gamma cytokine pathways have a role in chronic autoimmunity, which is considered mainly a dysfunction of adaptive immunity. The extent to which they contribute to innate immunity is, however, unknown. We used a mouse model of acute kidney ischemia-reperfusion injury (IRI) to test the hypothesis that early production of IL-23 and IL-12 following IRI activates downstream IL-17 and IFN-gamma signaling pathways and promotes kidney inflammation. Deficiency in IL-23, IL-17A, or IL-17 receptor (IL-17R) and mAb neutralization of CXCR2, the p19 subunit of IL-23, or IL-17A attenuated neutrophil infiltration in acute kidney IRI in mice. We further demonstrate that IL-17A produced by GR-1+ neutrophils was critical for kidney IRI in mice. Activation of the IL-12/IFN-gamma pathway and NKT cells by administering alpha-galactosylceramide-primed bone marrow-derived DCs increased IFN-gamma production following moderate IRI in WT mice but did not exacer! bate injury or enhance IFN-gamma production in either Il17a-/- or Il17r-/- mice, which suggested that IL-17 signaling was proximal to IFN-gamma signaling. This was confirmed by the finding that IFN-gamma administration reversed the protection seen in Il17a-/- mice subjected to IRI, whereas IL-17A failed to reverse protection in Ifng-/- mice. These results demonstrate that the innate immune component of kidney IRI requires dual activation of the IL-12/IFN-gamma and IL-23/IL-17 signaling pathways and that neutrophil production of IL-17A is upstream of IL-12/IFN-gamma. These mechanisms might contribute to reperfusion injury in other organs. PMID: 20038794 [PubMed - indexed for MEDLINE] | | |
| Influence of endothelial progenitor cells and platelet gel on tissue-engineered bone ectopically in goats.
January 21, 2010 at 9:52 AM
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| | Influence of endothelial progenitor cells and platelet gel on tissue-engineered bone ectopically in goats. Tissue Eng Part A. 2009 Nov;15(11):3669-77 Authors: Geuze RE, Wegman F, Oner FC, Dhert WJ, Alblas J For the development of functional large bone tissue constructs, optimal oxygen and nutrients supply of seeded multipotent stromal cells (MSCs) is likely dependent on vascularization. The introduction of endothelial progenitor cells (EPCs) to MSC cultures might enhance vascularization and therefore increase bone formation. In this study we cocultured MSCs and EPCs and investigated performance and bone formation both in vitro and in vivo. The EPCs used were characterized by uptake of acetylated low-density lipoproteins, binding of isolectin B4 and expression of platelet endothelial cell adhesion molecule. EPC/MSC in vitro coculture showed that both cell types exerted a positive effect on proliferation of the other. For the in vivo studies, we applied platelet-leukocyte gel (PLG), containing several growth factors, as a means to further induce vascularization and thereby enhance bone formation. Cocultures and monocultures were combined with either PLG or plasma, seed! ed on ceramic scaffolds, and implanted intramuscularly in nine goats. After 16 weeks of implantation, it turned out that seeding MSCs and EPCs both resulted in significant more bone lining the scaffold than the unseeded controls, and MSCs and cocultures with highest MSC/EPC ratio were most competent. Cocultures did not show a higher bone content than the monoculture of MSCs. Fluorochrome incorporation results showed that the presence of seeded cells, either MSCs or EPCs, in the constructs accelerated bone formation. Finally, the addition of PLG instead of plasma did have a positive influence on the quantity of incorporated bone. PMID: 19499998 [PubMed - indexed for MEDLINE] | | |
| Study of the crosstalk between hepatocytes and endothelial cells using a novel multicompartmental bioreactor: a comparison between connected cultures and cocultures.
January 21, 2010 at 9:52 AM
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| | Study of the crosstalk between hepatocytes and endothelial cells using a novel multicompartmental bioreactor: a comparison between connected cultures and cocultures. Tissue Eng Part A. 2009 Nov;15(11):3635-44 Authors: Guzzardi MA, Vozzi F, Ahluwalia AD The liver and other organs are connected to each other through the bloodstream. Therefore, the connection between tissues is generally mediated by soluble molecules able to cross the endothelial wall of capillaries. We developed a multicompartmental device, multicompartmental bioreactor (MCB), designed to mimic the connection between different tissues in which crosstalk is mediated by soluble molecules transported through the blood. A comparative study of the crosstalk between hepatocytes (HepG2) and endothelial cells (human umbilical vein endothelial cells) in connected culture in the MCB and in a traditional static coculture system was performed by analyzing glucose consumption and secretion of albumin, urea, and nitric oxide. When hepatocytes and endothelial cells were cultured together, the production of albumin and urea increased, and the increase was higher in the MCB than in traditional static coculture. In spite of this enhanced metabolic activity, the cro! sstalk between hepatocytes and endothelial cell leads to decreased glucose consumption with respect to hepatocytes alone, both in static and in dynamic conditions. However, the dynamic connected culture has a higher rate of metabolite synthesis and secretion with respect to cocultures. This means a more efficient use of energetic substrates and enhanced hepatocyte function in the MCB. PMID: 19496676 [PubMed - indexed for MEDLINE] | | |
| Characterization of umbilical cord blood-derived late outgrowth endothelial progenitor cells exposed to laminar shear stress.
January 21, 2010 at 9:52 AM
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| | Characterization of umbilical cord blood-derived late outgrowth endothelial progenitor cells exposed to laminar shear stress. Tissue Eng Part A. 2009 Nov;15(11):3575-87 Authors: Brown MA, Wallace CS, Angelos M, Truskey GA Endothelial progenitor cells isolated from umbilical cord blood (CB-EPCs) represent a promising source of endothelial cells for synthetic vascular grafts and tissue-engineered blood vessels since they are readily attainable, can be easily isolated, and possess a high proliferation potential. The objective of this study was to compare the functional behavior of late outgrowth CB-EPCs with human aortic endothelial cells (HAECs). CB-EPCs and HAECs were cultured on either smooth muscle cells in a coculture model of a tissue-engineered blood vessels or fibronectin adsorbed to Teflon-AF-coated glass slides. Late outgrowth CB-EPCs expressed endothelial cell-specific markers and were negative for the monocytic marker CD14. CB-EPCs have higher proliferation rates than HAECs, but are slightly smaller in size. CB-EPCs remained adherent under supraphysiological shear stresses, oriented and elongated in the direction of flow, and expressed similar numbers of alpha(5)beta(1) an! d alpha(v)beta(3) integrins and antithrombotic genes compared to HAECs. There were some differences in mRNA levels of E-selectin and vascular cell adhesion molecule 1 between CB-EPCs and HAECs; however, protein levels were similar on the two cell types, and CB-EPCs did not support adhesion of monocytes in the absence of tumor necrosis factor-alpha stimulation. Although CB-EPCs expressed significantly less endothelial nitric oxide synthase protein after exposure to flow than HAECs, nitric oxide levels induced by flow were not significantly different. These results suggest that late outgrowth CB-EPCs are functionally similar to HAECs under flow conditions and are a promising cell source for cardiovascular therapies. PMID: 19480571 [PubMed - indexed for MEDLINE] | | |
| Collagen-binding human epidermal growth factor promotes cellularization of collagen scaffolds.
January 21, 2010 at 9:52 AM
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| | Collagen-binding human epidermal growth factor promotes cellularization of collagen scaffolds. Tissue Eng Part A. 2009 Nov;15(11):3589-96 Authors: Yang Y, Zhao Y, Chen B, Han Q, Sun W, Xiao Z, Dai J Previous studies have demonstrated that epidermal growth factor (EGF) can promote tissue regeneration effectively. The aim of the present study was to combine a collagen-binding domain (CBD) with native EGF (NAT-EGF) to form a fusion protein, aiming at that it could bind to collagen scaffolds specifically. This approach could restrict the diffusion of EGF despite of extracellular fluids and limit the release of EGF to surrounding tissues. Thus, the retained CBD-EGF would render a continual function during the tissue regeneration. In our study, in vitro bioactivity assay showed that there was no significant difference between CBD-EGF and NAT-EGF to stimulate human fibroblasts to proliferate. In the collagen-binding assay, CBD-EGF exhibited a specific binding ability to collagen compared to NAT-EGF. Finally, in vivo experiment demonstrated that CBD-EGF-loaded collagen membranes uniformly possess a high capability to promote cellularization of scaffolds as compared w! ith that of NAT-EGF. All results aforementioned suggested that collagen loaded with CBD-EGF is a functional biomaterial with potential clinical applications. PMID: 19480569 [PubMed - indexed for MEDLINE] | | |
| Effect of serum and insulin modulation on the organization and morphology of matrix synthesized by bovine corneal stromal cells.
January 21, 2010 at 9:52 AM
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| | Effect of serum and insulin modulation on the organization and morphology of matrix synthesized by bovine corneal stromal cells. Tissue Eng Part A. 2009 Nov;15(11):3559-73 Authors: Bueno EM, Saeidi N, Melotti S, Ruberti JW The in vitro production of highly organized collagen fibrils by corneal keratocytes in a three-dimensional scaffold-free culture system presents a unique opportunity for the direct observation of organized matrix formation. The objective of this investigation was to develop such a culture system in a glass substrate (for optical accessibility) and to directly examine the effect of reducing serum and/or increasing insulin on the stratification and secretion of aligned matrix by fourth- to fifth-passage bovine corneal stromal keratocytes. Medium concentrations of 0%, 1%, or 10% fetal bovine serum and 0% or 1% insulin-transferrin-selenium were investigated. High-resolution differential interference contrast microscopy, quick-freeze/deep-etch, and conventional transmission electron microscopy were used to monitor the evolution, morphology, and ultrastructure of the cell-matrix constructs. In a medium containing 1% each of serum and insulin-transferrin-selenium, stroma! l cells stratified and secreted abundant and locally aligned matrix, generating the thickest cell-matrix constructs (allowing handling with forceps). The results of this study have the potential to significantly advance the field of developmental functional engineering of load-bearing tissues by (i) elucidating cues that modulate in vitro cell secretion of organized matrix and (ii) establishing an optically accessible cell culture system for investigating the mechanism of cell secretion of aligned collagen fibrils. PMID: 19480568 [PubMed - indexed for MEDLINE] | | |
| Octacalcium phosphate-precipitated alginate scaffold for bone regeneration.
January 21, 2010 at 9:52 AM
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| | Octacalcium phosphate-precipitated alginate scaffold for bone regeneration. Tissue Eng Part A. 2009 Nov;15(11):3525-35 Authors: Fuji T, Anada T, Honda Y, Shiwaku Y, Koike H, Kamakura S, Sasaki K, Suzuki O The present study was designed to investigate whether octacalcium phosphate (OCP)-precipitated alginate (Alg) promotes osteoblastic cell proliferation and bone regeneration in comparison with Alg itself. Alg, known to lack mammal cell attachment capability, was used as the matrix to test the distribution effect of OCP in a three-dimensional environment. A series of Alg/OCP scaffolds with different pore sizes was prepared by centrifuging Alg gels precipitated by OCP crystals. The scaffolds had a bimodal distribution of pores (ultrafine pores: approximately 100 nm; relatively large pores: from 6.0 to 51.7 microm) and over 86% porosity. The osteoconductive capability of Alg/OCP was determined by examining mouse bone marrow stromal ST-2 cell proliferation after 3 days in vitro and bone regeneration in mouse calvaria critical-sized defect after 21 days. The analyses showed that ST-2 cell proliferation and bone regeneration increased with an increase in the pore size an! d reached the highest level in the 51.7 microm pore scaffold. The results suggest that OCP-precipitated Alg provides a better scaffold for osteoblasts to attach and proliferate in a three-dimensional environment and promotes bone regeneration, indicating that OCP is a candidate material to modify the surface of non-cell-interactive polymeric scaffolds, such as Alg, into an osteogenic condition. PMID: 19456237 [PubMed - indexed for MEDLINE] | | |
| Addition of hyaluronic acid to alginate embedded chondrocytes interferes with insulin-like growth factor-1 signaling in vitro and in vivo.
January 21, 2010 at 9:52 AM
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| | Addition of hyaluronic acid to alginate embedded chondrocytes interferes with insulin-like growth factor-1 signaling in vitro and in vivo. Tissue Eng Part A. 2009 Nov;15(11):3449-59 Authors: Yoon DM, Curtiss S, Reddi AH, Fisher JP The development of an engineered tissue requires a clear understanding of the interactions between the individual components. In this study, we investigated how the addition of hyaluronic acid (HA) to a cartilage tissue engineered scaffold alters chondrocytic expression, and specifically the expression of insulin-like growth factor-1 (IGF-1) signaling molecules. Bovine chondrocytes were embedded (7 million cells/mL) in 2.0% w/v alginate hydrogels containing varying HA concentrations (0, 0.05, 0.50, and 5.00 mg/mL). In vitro constructs were cultured with exogenous IGF-1, and gene expression was monitored at days 1, 4, and 8 for IGF-1, IGF-1 receptor (IGF-1R), IGF binding protein 3 (IGFBP-3), type II collagen and type I collagen. In vivo constructs were precultured for 24 h with exogenous IGF-1 before being implanted subcutaneously in severe combined immunodeficient mice; samples were analyzed using histology at days 7, 14, and 21. Results indicate that, with the ad! dition of high levels (5.00 mg/mL) of HA, IGF-1 can become entrapped within the matrix and therefore interfere with the delivery of IGF-1 to chondrocytes. In vitro and in vivo data showed that increasing the concentration of HA in an alginate hydrogel can decrease chondrocyte IGF-1 expression. IGF-1R expression did not change with HA concentration, and the addition of any HA did not significantly alter IGFBP-3 expression. Chondrocytes continuously expressed phenotypic type II collagen in vitro and in vivo throughout the study for all the groups. However, for all the HA concentrations investigated, chondrocytes showed more of a fibroblastic phenotype, as indicated by greater expression of type I collagen than with no HA, in vitro and in vivo. In conclusion, these results indicate that HA interferes with the delivery of IGF-1 to chondrocytes, affecting the endogenous expression of IGF-1 signaling molecules and the resulting chondrocyte phenotype, and therefore demonstrating t! he critical effect of biomaterial scaffolds on encapsulated ce! ll funct ion. PMID: 19426107 [PubMed - indexed for MEDLINE] | | |
| Effect of serum and growth factors on chondrogenic differentiation of synovium-derived stromal cells.
January 21, 2010 at 9:52 AM
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| | Effect of serum and growth factors on chondrogenic differentiation of synovium-derived stromal cells. Tissue Eng Part A. 2009 Nov;15(11):3401-15 Authors: Lee S, Kim JH, Jo CH, Seong SC, Lee JC, Lee MC We used fetal bovine serum (FBS) and different growth factors to investigate their potential for inducing chondrogenic differentiation of synovium-derived stromal cells. Human synovium was harvested from patients suffering from osteoarthritis and expanded in monolayer. To evaluate the effect of serum and growth factors on chondrogenic differentiation, 10 ng/mL of transforming growth factor-beta1 (TGF-beta1), 100 ng/mL of bone morphogenic protein-2 (BMP-2), 100 ng/mL of insulin-like growth factor-1, 20 ng/mL of basic fibroblast growth factor (bFGF), and 10% FBS were added to the chemically defined chondrogenic medium singly or in combination during pellet culture for 21 days. The cell size and weight, glycosaminoglycan content, histology, and cartilage matrix-associated genes expression were analyzed. TGF-beta1 alone and TGF-beta1 + BMP-2 induced chondrogenic differentiation of synovium-derived stromal cells and synthesized cartilage-like matrix confirmed by histol! ogical analysis and immunohistochemistry. FBS, BMP-2, insulin-like growth factor-1, and bFGF as a single factor or other combinations except for TGF-beta1 + BMP-2 hardly induced chondrogenesis. Chondrogenic differentiation appeared to be inhibited when bFGF or the serum was added to the chondrogenic medium during pellet culture. The results of this study demonstrate the negative or positive role of serum and growth factors on chondrogenic differentiation of synovium-derived stromal cells. PMID: 19402787 [PubMed - indexed for MEDLINE] | | |
| Long-term superior performance of a stem cell/hepatocyte device for the treatment of acute liver failure.
January 21, 2010 at 9:52 AM
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| | Long-term superior performance of a stem cell/hepatocyte device for the treatment of acute liver failure. Tissue Eng Part A. 2009 Nov;15(11):3377-88 Authors: Yagi H, Parekkadan B, Suganuma K, Soto-Gutierrez A, Tompkins RG, Tilles AW, Yarmush ML Cell-based technologies to support/restore organ function represent one of the most promising avenues in the treatment of acute liver failure (ALF). Recently, mesenchymal stem cells (MSCs) have been reported as a new therapeutic for inflammatory conditions. Here, we demonstrate the efficacy of MSCs, when cocultured with hepatocytes, to provide combination hepatic and antiinflammatory therapy in the setting of ALF. MSCs were shown to have multiple beneficial effects in vitro that were relevant in a therapeutic context, including (1) hepatocellular functional support, (2) secretion of molecules that inhibit hepatocyte apoptosis, and (3) modulation of an acute phase response by hepatocytes cultured in ALF-induced serum. In addition, we show that the MSC secretome is dynamically changed in response to serum exposure from ALF rats. We then conducted a therapeutic trial of liver assist devices (LADs). LADs containing cocultures of MSCs and hepatocytes provided a greater! survival benefit compared to other coculture and monocellular control LADs. Treatment with MSC-hepatocyte devices was associated with specific improvements in hepatic functional and histological parameters as well as decreasing inflammatory serum cytokine levels, validating a combined therapeutic effect. Moreover, MSC coculture reduced the overall cell mass of the device by an order of magnitude. These findings demonstrate the importance of nonparenchymal cells in the cellular composition of LADs, and strongly support the integration of MSCs into hepatocyte-coculture-based LADs as a potential destination therapy for ALF. PMID: 19397469 [PubMed - indexed for MEDLINE] | | |
| Efficient derivation of alveolar type II cells from embryonic stem cells for in vivo application.
January 21, 2010 at 9:52 AM
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| | Efficient derivation of alveolar type II cells from embryonic stem cells for in vivo application. Tissue Eng Part A. 2009 Nov;15(11):3351-65 Authors: Roszell B, Mondrinos MJ, Seaton A, Simons DM, Koutzaki SH, Fong GH, Lelkes PI, Finck CM In the present study, mouse embryonic stem cells (ESCs) were differentiated into alveolar epithelial type II (AEII) cells for endotracheal injection. These enriched lung-like populations expressed lung epithelial markers SP-A, SP-B, SP-C, and CC10. First we show that rapid differentiation of ESCs requires a dissociated seeding method instead of an embryoid body culture method. We then investigated a two-step differentiation of ESCs into definitive endoderm by activin or A549-conditioned medium as a precursor to lung epithelial cells. When conditioned medium from A549 cells was used to derive endoderm, yield was increased above that of activin alone. Further studies showed that Wnt3a may be one of the secreted factors produced by A549 cells and promotes definitive endoderm differentiation, in part, through suppression of primitive endoderm. Activin and Wnt3a together at appropriate doses with dissociated cell seeding promoted greater endoderm yield than activin alo! ne. Next, fibroblast growth factor 2 was shown to induce a dose-dependent expression of SPC, and these cells contained lamellar bodies characteristic of mature AEII cells from ESC-derived endoderm. Finally, ES-derived lung cells were endotracheally injected into preterm mice with evidence of AEII distribution within the lung parenchyma. This study concludes that a recapitulation of development may enhance derivation of an enriched population of lung-like cells for use in cell-based therapy. PMID: 19388834 [PubMed - indexed for MEDLINE] | | |
| Perlecan domain IV peptide stimulates salivary gland cell assembly in vitro.
January 21, 2010 at 9:52 AM
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| | Perlecan domain IV peptide stimulates salivary gland cell assembly in vitro. Tissue Eng Part A. 2009 Nov;15(11):3309-20 Authors: Pradhan S, Zhang C, Jia X, Carson DD, Witt R, Farach-Carson MC Treatment of xerostomia would benefit from development of a functional implantable artificial salivary gland. Salivary gland tissue from surgical patients was assessed by histology and immunohistochemistry to establish the phenotype of normal salivary gland cells including the native basement membranes. Ductal and acinar cells were identified in tissue and cultured cells from dispersed tissue. High levels of laminin and perlecan/HSPG2 (heparan sulfate proteoglycan 2) were noted in basement membranes, and perlecan also was secreted and organized by cultured acinar populations, which formed lobular structures that mimicked intact glands when cultured on Matrigel or a bioactive peptide derived from domain IV of perlecan. On either matrix, large acini-like lobular structures grew and formed connections between the lobes. alpha-Amylase secretion was confirmed by staining and activity assay. Biomarkers, including tight junction protein E-cadherin and water channel prote! in aquaporin 5 found in tissue, were expressed in cultured acinar cells. Cells cultured on Matrigel or domain IV of perlecan peptide organized stress fibers and activated focal adhesion kinase. We report a novel technique to isolate acinar cells from human salivary gland and identify a human peptide sequence in perlecan that triggers differentiation of salivary gland cells into self-assembling acini-like structures that express essential biomarkers and which secrete alpha-amylase. PMID: 19382872 [PubMed - indexed for MEDLINE] | | |
| Substrate-induced assembly of fibronectin into networks: influence of surface chemistry and effect on osteoblast adhesion.
January 21, 2010 at 9:52 AM
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| | Substrate-induced assembly of fibronectin into networks: influence of surface chemistry and effect on osteoblast adhesion. Tissue Eng Part A. 2009 Nov;15(11):3271-81 Authors: Rico P, Rodríguez Hernández JC, Moratal D, Altankov G, Monleón Pradas M, Salmerón-Sánchez M The influence of surface chemistry-substrates with controlled surface density of -OH groups-on fibronectin (FN) conformation and distribution is directly observed by atomic force microscopy (AFM). FN fibrillogenesis, which is known to be a process triggered by interaction with integrins, is shown in our case to be induced by the substrate (in absence of cells), which is able to enhance FN-FN interactions leading to the formation of a protein network on the material surface. This phenomenon depends both on surface chemistry and protein concentration. The level of the FN fibrillogenesis was quantified by calculating the fractal dimension of the adsorbed protein from image analysis of the AFM results. The total amount of adsorbed FN is obtained by making use of a methodology that employs Western blotting combined with image analysis of the corresponding protein bands, with the lowest sensitivity threshold equal to 15 ng of adsorbed protein. Further, FN adsorption is ! correlated to human osteoblast adhesion through morphology and actin cytoskeleton formation. Actin polymerization is in need of the formation of the protein network on the substrate's surface. Cell morphology is more rounded (as quantified by calculating the circularity of the cells by image analysis) when the degree of FN fibrillogenesis on the substrate is lower. PMID: 19382854 [PubMed - indexed for MEDLINE] | | |
| Engineering of large cartilaginous tissues through the use of microchanneled hydrogels and rotational culture.
January 21, 2010 at 9:52 AM
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| | Engineering of large cartilaginous tissues through the use of microchanneled hydrogels and rotational culture. Tissue Eng Part A. 2009 Nov;15(11):3213-20 Authors: Buckley CT, Thorpe SD, Kelly DJ The development of functional engineered cartilaginous tissues of sufficient size that can be used clinically to treat large defects remains a major and significant challenge. This study investigated if the introduction of microchannels into chondrocyte-seeded agarose hydrogels would result in the formation of a superior and more homogenous cartilaginous tissue as a result of enhanced nutrient transport. Microchanneled construct cylinders were fabricated via a molding process utilizing a pillared structure to create the required architecture. Constructs were subjected to either constant rotation in a rotational bioreactor system or free-swelling conditions. After 28 days of free-swelling culture the presence of microchannels did not enhance glycosaminoglycan accumulation within the core of the construct compared to solid constructs (0.317 +/- 0.002% w/w vs. 0.401 +/- 0.020% w/w). However, under dynamically rotating conditions, glycosaminoglycan accumulation in the! cores (1.165 +/- 0.132% w/w) of microchannel constructs were similar to that in the periphery (1.23 +/- 0.074% w/w) of solid constructs, although still significantly lower than their corresponding periphery (1.64 +/- 0.133% w/w) after 28 days. These results confirm that cellular nutrient consumption is primarily responsible for creating the spatial gradients in molecules regulating the biosynthetic activity of chondrocytes through the volume of hydrogels, and that changing the scaffold architecture alone may have little effect while the inherent diffusivity of the material remains high. Rather, a combination of forced convection and modified scaffold architecture is necessary to engineer large cartilaginous tissues in vitro. PMID: 19374490 [PubMed - indexed for MEDLINE] | | |
| Synthetic poly(amino acid) hydrogels with incorporated cell-adhesion peptides for tissue engineering.
January 20, 2010 at 6:04 PM
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| | Synthetic poly(amino acid) hydrogels with incorporated cell-adhesion peptides for tissue engineering. J Tissue Eng Regen Med. 2010 Jan 18; Authors: Studenovská H, Vodička P, Proks V, Hlučilová J, Motlík J, Rypáček F Preparation of soft poly(amino acid) hydrogels containing biomimetic cell-adhesive peptides was investigated. Covalently crosslinked gels were formed by radical co-polymerization of methacryloylated macromonomer poly[N(5)-(2-hydroxyethyl)-L-glutamine-stat-L-alanine-stat-methacryloyllysine] with 2-hydroxyethyl methacrylate (HEMA) as minor co-monomer. Hydrogels carrying biomimetic peptides were prepared by using methacryloylated peptides, such as methacryloyl-GGGRGDSG-OH and methacryloyl-GGGYIGSR-OH, as additional monomers in the polymerization mixture. Mechanical stability and swelling in water of the hydrogels obtained for different solid:water and polypeptide:HEMA ratios were evaluated. The microporosity of gels (5-20 microm), dependent on the polyHEMA phase separation in water, was followed by low-vacuum SEM. The effect of biomimetic modification of hydrogels with RGDS and YIGSR peptides on the seeding efficiency of porcine mesenchymal stem cells (MSCs) was stud! ied in vitro. While unmodified hydrogels showed very low cell adhesion, due to their highly hydrophilic nature, the incorporation of adhesive peptides significantly improved the adhesion and viability of seeded cells. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20084624 [PubMed - as supplied by publisher] | | |
| Induced pluripotent stem cells (iPSCs): the emergence of a new champion in stem cell technology-driven biomedical applications.
January 20, 2010 at 6:04 PM
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| | Induced pluripotent stem cells (iPSCs): the emergence of a new champion in stem cell technology-driven biomedical applications. J Tissue Eng Regen Med. 2010 Jan 18; Authors: Das AK, Pal R Pluripotent stem cells possess the unique property of differentiating into all other cell types of the human body. Further, the discovery of induced pluripotent stem cells (iPSCs) in 2006 has opened up new avenues in clinical medicine. In simple language, iPSCs are nothing but somatic cells reprogrammed genetically to exhibit pluripotent characteristics. This process utilizes retroviruses/lentiviruses/adenovirus/plasmids to incorporate candidate genes into somatic cells isolated from any part of the human body. It is also possible to develop disease-specific iPSCs which are most likely to revolutionize research in respect to the pathophysiology of most debilitating diseases, as these can be mimicked ex vivo in the laboratory. These models can also be used to study the safety and efficacy of known drugs or potential drug candidates for a particular diseased condition, limiting the need for animal studies and considerably reducing the time and money required to deve! lop new drugs. Recently, functional neurons, cardiomyocytes, pancreatic islet cells, hepatocytes and retinal cells have been derived from human iPSCs, thus re-confirming the pluripotency and differentiation capacity of these cells. These findings further open up the possibility of using iPSCs in cell replacement therapy for various degenerative disorders. In this review we highlight the development of iPSCs by different methods, their biological characteristics and their prospective applications in regenerative medicine and drug screening. We further discuss some practical limitations pertaining to this technology and how they can be averted for the betterment of human life. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20084623 [PubMed - as supplied by publisher] | | |
| Porous polylactide/beta-tricalcium phosphate composite scaffolds for tissue engineering applications.
January 20, 2010 at 6:04 PM
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| | Porous polylactide/beta-tricalcium phosphate composite scaffolds for tissue engineering applications. J Tissue Eng Regen Med. 2010 Jan 18; Authors: Haaparanta AM, Haimi S, Ellä V, Hopper N, Miettinen S, Suuronen R, Kellomäki M Porous polylactide/beta-tricalcium phosphate (PLA/beta-TCP) composite scaffolds were fabricated by freeze-drying. The aim of this study was to characterize these graded porous composite scaffolds in two different PLA concentrations (2 and 3 wt%). Also, three different beta-TCP ratios (5, 10 and 20 wt%) were used to study the effect of beta-TCP on the properties of the polymer. The characterization was carried out by determining the pH, weight change, component ratios, thermal stability, inherent viscosity and microstructure of the scaffolds in 26 weeks of hydrolysis. This study indicated that no considerable change was noticed in the structure of the scaffolds when the beta-TCP filler was added. Also, the amount of beta-TCP did not affect the pore size or the pore distribution in the scaffolds. We observed that the fabrication method improved the thermal stability of the samples. Our results suggest that, from the structural point of view, these scaffolds could ha! ve potential for the treatment of osteochondral defects in tissue engineering applications. The porous bottom surface of the scaffold and the increased osteogenic differentiation potential achieved with beta-TCP particles may encourage the growth of bone cells. In addition, the dense surface skin of the scaffold may inhibit the ingrowth of osteoblasts and bone tissue, while simultaneously encouraging the ingrowth of chondrocytes. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20084622 [PubMed - as supplied by publisher] | | |
| Fabrication of scaffold-free contractile skeletal muscle tissue using magnetite-incorporated myogenic C2C12 cells.
January 20, 2010 at 6:04 PM
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| | Fabrication of scaffold-free contractile skeletal muscle tissue using magnetite-incorporated myogenic C2C12 cells. J Tissue Eng Regen Med. 2010 Jan 18; Authors: Fujita H, Shimizu K, Yamamoto Y, Ito A, Kamihira M, Nagamori E We have fabricated a functional skeletal muscle tissue using magnetite-incorporated myogenic cell line C2C12 and a magnetic field. Magnetite-incorporated C2C12 cells were patterned linearly on a monolayer of fibroblast NIH3T3 cells, using a magnetic field concentrator. After induction of differentiation, the C2C12 cells fused and formed multi-nucleated myotubes. The 3T3 layer became detached in a sheet-like manner after cultivation in differentiation medium for 5-8 days. When two separate collagen films were placed on a culture dish as tendon structures, a cylindrical construct was formed. Histological observation of the fabricated cylindrical tissue revealed the presence of multinucleate cells within it. Immunofluorescence staining of the construct showed the presence of sarcomere structures within the construct. Western blot analysis showed that muscle proteins were expressed in the construct. When the construct was stimulated with electric pulses, it exhibited ! active tension of approximately 1 microN. These results demonstrate that functional skeletal muscle tissue was formed through magnetic force-based tissue engineering. This is the first report of fabrication of skeletal muscle tissue with active tension-generating capability using magnetic force-based tissue engineering. The scaffold-free skeletal muscle tissue engineering technique presented in this study will be useful for regenerative medicine, drug screening or use as a bio-actuator. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20084621 [PubMed - as supplied by publisher] | | |
| An improved in vivo method for atrioventricular node ablation via thoracotomy.
January 20, 2010 at 6:04 PM
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| | An improved in vivo method for atrioventricular node ablation via thoracotomy. Braz J Med Biol Res. 2010 Jan 15; Authors: Maciver RH, Stewart RD, Backer CL, Tsao S, Harrington DA, Mavroudis C The atrioventricular (AV) node is permanently damaged in approximately 3% of congenital heart surgery operations, requiring implantation of a permanent pacemaker. Improvements in pacemaker design and in alternative treatment modalities require an effective in vivo model of complete heart block (CHB) before testing can be performed in humans. Such a model should enable accurate, reliable, and detectable induction of the surgical pathology. Through our laboratory's efforts in developing a tissue engineering therapy for CHB, we describe here an improved in vivo model for inducing chronic AV block. The method employs a right thoracotomy in the adult rabbit, from which the right atrial appendage may be retracted to expose an access channel for the AV node. A novel injection device was designed, which both physically restricts needle depth and provides electrical information via electrocardiogram interface. This combination of features provides real-time guidance to the! researcher for confirming contact with the AV node, and documents its ablation upon formalin injection. While all animals tested could be induced to acute AV block, those with ECG guidance were more likely to maintain chronic heart block >12 h. Our model enables the researcher to reproduce both CHB and the associated peripheral fibrosis that would be present in an open congenital heart surgery, and which would inevitably impact the design and utility of a tissue engineered AV node replacement. PMID: 20084330 [PubMed - as supplied by publisher] | | |
| Testicular germline stem cells.
January 20, 2010 at 6:04 PM
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| | Testicular germline stem cells. Nat Rev Urol. 2010 Jan 19; Authors: Kee K, Reijo Pera RA, Turek PJ Stem cells have the ability to both differentiate into other mature cell types and maintain an undifferentiated state by self-renewal. These unique properties form the basis for stem cell use in organ replacement and tissue regeneration in clinical medicine. Currently, embryonic stem cells are the best-studied stem cell type. However alternative stem cells such as induced pluripotent stem cells and other adult stem cells are also being actively investigated for their potential for cell-based therapy. Among adult stem cells, emerging research has focused on evaluating the pluripotency potential of testis stem cells. To date, stem cells with embryonic-like potential have been created from adult testis germ cells. These cells could provide patient-specific, non-embryo-derived stem cells for men in the future. PMID: 20084076 [PubMed - as supplied by publisher] | | |
| Aqueous impregnation of porous beta-tricalcium phosphate scaffolds.
January 20, 2010 at 6:04 PM
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| | Aqueous impregnation of porous beta-tricalcium phosphate scaffolds. Acta Biomater. 2010 Jan 15; Authors: Stähli C, Bohner M, Bashoor-Zadeh M, Doebelin N, Baroud G The ability of a porous bone graft substitute to be impregnated with an aqueous solution is of great importance for tissue engineering and in vivo applications. This study presents an impregnation test setup and assesses the effect of various synthesis parameters such as sintering temperature, composition, macroporosity and macropore size on the impregnation properties of porous beta-tricalcium phosphate scaffolds dipped in water. Among those parameters, the macropore size had by far the largest effect; generally, the bigger the macropore size was, the lower the saturation level was. The results also showed that impregnation was less complete when the samples were fully dipped in water than when they were only partially dipped due to the requirement for the system to create air bubbles under water. PMID: 20083239 [PubMed - as supplied by publisher] | | |
| Synthesis and In Vitro Evaluation of Gelatin/Hydroxyapatite Graft Copolymers to Form Bionanocomposites.
January 20, 2010 at 6:04 PM
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| | Synthesis and In Vitro Evaluation of Gelatin/Hydroxyapatite Graft Copolymers to Form Bionanocomposites. Int J Biol Macromol. 2010 Jan 15; Authors: Haroun AA, Migonney V The combination of gelatin (Gel) with a bioactive component hydroxyapatite (HA) and cartilage powder CP) to form biocomposites takes advantage of the osteoconductivity and osteoinductivity properties. The studies on bionanocomposites containing HA, CP fillers and Gel are still being conducted. In this present study, the bioactive fillers were loaded onto poly(hydroxylethylmethacrylate) and poly(hydroxylethylmethacrylate-co-methyl methacrylate) grafted gelatin copolymers to produce novel bionanocomposites having osteoconductive and osteoinductive properties. The resulting bionanocomposites were assessed by ATR-IR and SEM-EDX techniques to prove the interaction between different matrices. In vitro behavior of these bionanocomposites was performed in SBF for 21 days at pH 7.4 to verify formation of the apatite layer on the surfaces and its enhancement. The results confirmed the formation of thick plentiful aggregated (hexagonal or spherical) nanoparticles with a brig! ht color (apatite layer) containing carbonate ions onto the surface of composites especially these containing CP and P(HEMA-co-MMA) having bone cement formation in their structure. These novel bionanocomposites have unique bioactivity that can be applied in bone implants as scaffolds and tissue engineering in future. PMID: 20083133 [PubMed - as supplied by publisher] | | |
| Neural Crest Regionalisation for Enteric Nervous System Formation: Implications for Hirschsprung's Disease and Stem Cell Therapy.
January 20, 2010 at 6:04 PM
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| | Neural Crest Regionalisation for Enteric Nervous System Formation: Implications for Hirschsprung's Disease and Stem Cell Therapy. Dev Biol. 2010 Jan 15; Authors: Zhang D, Brinas IM, Binder BJ, Landman KA, Newgreen DF Midbrain, hindbrain and vagal neural crest (NC) produced abundant enteric nervous system (ENS) in co-grafted aneural hindgut and midgut, using chick-quail chorio-allantoic membrane grafts, forming complete myenteric and submucosal plexuses. This ability dropped suddenly in cervical and thoracic NC levels, furnishing an incomplete ENS in one or both plexuses. Typically, one plexus was favored over the other. This deficiency was not caused by lower initial trunk NC number, yet overloading the initial number decreased the deficiency. No qualitative difference in neuronal and glial differentiation between cranial and trunk levels was observed. All levels formed HuC/D+ve, NOS+ve, ChAT+ve, TH-ve enteric neurons with SoxE+ve, GFAP+ve, BFABP+ve glial cells. We mathematically modelled a proliferative difference between NC populations, with a plexus preference hierarchy, in the context of intestinal growth. High proliferation achieved an outcome similar to cranial NC, while! low proliferation described the trunk NC outcome of incomplete primary plexus and even more deficient secondary plexus. We conclude that cranial NC, relative to trunk NC, has a positionally-determined proliferation advantage favouring ENS formation. This has important implications for proposed NC stem cell therapy for Hirschsprung's disease, since such cells may need to be optimised for positional identity. PMID: 20083101 [PubMed - as supplied by publisher] | | |
| Translational systems biology of inflammation and healing.
January 20, 2010 at 6:04 PM
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| | Translational systems biology of inflammation and healing. Wound Repair Regen. 2010 Jan-Feb;18(1):3-7 Authors: Vodovotz Y Personalized medicine is a major goal for the future of healthcare, and we suggest that computational simulations are necessary in order to achieve it. Inflammatory diseases, both acute and chronic, represent an area in which personalized medicine is especially needed, given the high level of individual variability that characterizes these diseases. We have created such simulations, and have used them to gain basic insights into the inflammatory response under baseline, gene-knockout, and drug-treated experimental animals; for in silico experiments and clinical trials in sepsis, trauma, and wound healing; and to create patient-specific simulations in polytrauma, traumatic brain injury, and vocal fold inflammation. Since they include both circulating and tissue-level inflammatory mediators, these simulations transcend typical cytokine networks by associating inflammatory processes with tissue/organ damage via tissue damage/dysfunction. We suggest that computational! simulations are the cornerstone of Translational Systems Biology approaches for inflammatory diseases. PMID: 20082674 [PubMed - in process] | | |
| Discrepancies between metabolic activity and DNA content as tool to assess cell proliferation in cancer research.
January 20, 2010 at 6:04 PM
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| | Discrepancies between metabolic activity and DNA content as tool to assess cell proliferation in cancer research. J Cell Mol Med. 2010 Jan 15; Authors: Quent VM, Loessner D, Friis T, Reichert JC, Hutmacher DW Abstract Cell proliferation is a critical and frequently studied feature of molecular biology in cancer research. Therefore, various assays are available using different strategies to measure cell proliferation. Metabolic assays such as AlamarBlue, WST-1, and MTT, which were originally developed to determine cell toxicity, are being used to assess cell numbers. Additionally, proliferative activity can be determined by quantification of DNA content using fluorophores, such as CyQuant and PicoGreen. Referring to data published in high ranking cancer journals, 945 publications applied these assays over the past 14 years to examine the proliferative behaviour of diverse cell types. Within this study, mainly metabolic assays were used to quantify changes in cell growth yet these assays may not accurately reflect cellular proliferation rates due to a miscorrelation of metabolic activity and cell number. Testing this hypothesis, we compared metabolic activity of differen! t cell types, human cancer cells and primary cells, over a time period of 4 days using AlamarBlue and fluorometric assays CyQuant and PicoGreen to determine their DNA content. Our results show certain discrepancies in terms of over-estimation of cell proliferation with respect to the metabolic assay in comparison to DNA binding fluorophores. PMID: 20082656 [PubMed - as supplied by publisher] | | |
| [Cultivated corneal endothelial cell sheet transplantation in a primate model]
January 20, 2010 at 6:04 PM
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| | [Cultivated corneal endothelial cell sheet transplantation in a primate model] Nippon Ganka Gakkai Zasshi. 2009 Nov;113(11):1050-9 Authors: Koizumi N Our new surgical treatment for corneal endothelial dysfunction involves replacing damaged the corneal endothelium with healthy corneal endothelial cells cultivated and multiplied in vitro. Monkey corneal endothelial cells (MCECs) were cultivated on collagen type- I carriers for four weeks. The corneal endothelium of the monkeys was mechanically scraped, and the cultivated MCEC sheet was inserted into the anterior chamber and fixed to the Descemet's membrane with air. As controls, a collagen sheet without MCECs was transplanted into one eye, and a suspension of cultivated MCECs was injected into the anterior chamber in another eye. In the early postoperative period MCEC sheets were attached to Descemet's membrane and corneal clarity recovered. This was accompanied by a decrease in corneal thickness. Fluorescein DiI labeled donor corneal endothelial cells were detected on the host cornea on postoperative day7. After transplantation, the MCEC-transplanted corneas rem! ained clear for up to 4 years, and hexagonal cells of a density more than 1,500-2,000 cells/mm2 were observed by in vivo specular microscopy. Control eyes showed irreversible bullous keratopathy. We established a model of cultivated corneal endothelial transplantation for corneal endothelial dysfunction in primates whose corneal endothelial cells have less proliferative capacity in vivo. Our results suggest that this is a useful model for long-term observation in advance of future clinical application of cultivated corneal endothelial transplantation. PMID: 19994583 [PubMed - indexed for MEDLINE] | | |
| Genephony: a knowledge management tool for genome-wide research.
January 20, 2010 at 6:04 PM
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| | Genephony: a knowledge management tool for genome-wide research. BMC Bioinformatics. 2009;10:278 Authors: Nuzzo A, Riva A BACKGROUND: One of the consequences of the rapid and widespread adoption of high-throughput experimental technologies is an exponential increase of the amount of data produced by genome-wide experiments. Researchers increasingly need to handle very large volumes of heterogeneous data, including both the data generated by their own experiments and the data retrieved from publicly available repositories of genomic knowledge. Integration, exploration, manipulation and interpretation of data and information therefore need to become as automated as possible, since their scale and breadth are, in general, beyond the limits of what individual researchers and the basic data management tools in normal use can handle. This paper describes Genephony, a tool we are developing to address these challenges. RESULTS: We describe how Genephony can be used to manage large datesets of genomic information, integrating them with existing knowledge repositories. We illustrate its funct! ionalities with an example of a complex annotation task, in which a set of SNPs coming from a genotyping experiment is annotated with genes known to be associated to a phenotype of interest. We show how, thanks to the modular architecture of Genephony and its user-friendly interface, this task can be performed in a few simple steps. CONCLUSION: Genephony is an online tool for the manipulation of large datasets of genomic information. It can be used as a browser for genomic data, as a high-throughput annotation tool, and as a knowledge discovery tool. It is designed to be easy to use, flexible and extensible. Its knowledge management engine provides fine-grained control over individual data elements, as well as efficient operations on large datasets. PMID: 19728881 [PubMed - indexed for MEDLINE] | | | |
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