| Stem Cell Blog Returning to Action
January 19, 2010 at 10:45 PM
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| | A couple of days ago, we stepped on land for the first time in a month. The occasion was our arrival aboard our sailboat (and only home) in Barra de Navidad after two long ocean passages and visit to two islands in the Revillagigedo Archipelago about 350 miles west of mainland Mexico. We swam with giant manta rays, watched a humpback whale with a very young calf and snorkeled with a host of | | |
| Enhanced lipoplex-mediated gene expression in mesenchymal stem cells using reiterated nuclear localization sequence peptides.
January 19, 2010 at 6:49 AM
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| | Enhanced lipoplex-mediated gene expression in mesenchymal stem cells using reiterated nuclear localization sequence peptides. J Gene Med. 2010 Jan 15; Authors: Hoare M, Greiser U, Schu S, Mashayekhi K, Aydogan E, Murphy M, Barry F, Ritter T, O'Brien T BACKGROUND: Mesenchymal stem cells (MSC) are widely regarded as a promising tool for cellular therapy applications, and genetic modification by safe, liposome-based vectors may enhance their therapeutic potential. METHODS: The present study describes the use of a cationic lipid vector (Lipofectamine 2000) to deliver genes to MSC isolated from a number of species in vitro and determined the characteristics of this vector system in terms of dose, toxicity and the time course of expression. In addition, the optimal use of a nuclear localization sequence (NLS) to enhance gene expression was explored. RESULTS: Lipofection of human MSC did not adversely affect their ability to differentiate into osteogenic- and adipogenic lineages. Although human and rat MSC were found to take up lipoplexes with relative efficiency, lower levels of gene expression were detected in rabbit MSC, demonstrating a crucial effect of species. Peptides containing reiterated motifs of NLS were fo! und to significantly improve on the level of transgene expression. Optimal gene delivery was observed when a three-fold reiterated NLS sequence was included in the liposome formulation. CONCLUSIONS: Thus, nonviral gene delivery to MSC is feasible with efficiency being species dependent and can be enhanced by use of a three-fold reiterated NLS. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20082426 [PubMed - as supplied by publisher] | | |
| DNMT1 maintains progenitor function in self-renewing somatic tissue.
January 19, 2010 at 6:49 AM
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| | DNMT1 maintains progenitor function in self-renewing somatic tissue. Nature. 2010 Jan 17; Authors: Sen GL, Reuter JA, Webster DE, Zhu L, Khavari PA Progenitor cells maintain self-renewing tissues throughout life by sustaining their capacity for proliferation while suppressing cell cycle exit and terminal differentiation. DNA methylation provides a potential epigenetic mechanism for the cellular memory needed to preserve the somatic progenitor state through repeated cell divisions. DNA methyltransferase 1 (DNMT1) maintains DNA methylation patterns after cellular replication. Although dispensable for embryonic stem cell maintenance, the role for DNMT1 in maintaining the progenitor state in constantly replenished somatic tissues, such as mammalian epidermis, is unclear. Here we show that DNMT1 is essential for epidermal progenitor cell function. DNMT1 protein was found enriched in undifferentiated cells, where it was required to retain proliferative stamina and suppress differentiation. In tissue, DNMT1 depletion led to exit from the progenitor cell compartment, premature differentiation and eventual tissue loss! . Genome-wide analysis showed that a significant portion of epidermal differentiation gene promoters were methylated in self-renewing conditions but were subsequently demethylated during differentiation. Furthermore, UHRF1 (refs 9, 10), a component of the DNA methylation machinery that targets DNMT1 to hemi-methylated DNA, is also necessary to suppress premature differentiation and sustain proliferation. In contrast, Gadd45A and B, which promote active DNA demethylation, are required for full epidermal differentiation gene induction. These data demonstrate that proteins involved in the dynamic regulation of DNA methylation patterns are required for progenitor maintenance and self-renewal in mammalian somatic tissue. PMID: 20081831 [PubMed - as supplied by publisher] | | |
| Chemical reprogramming of Caenorhabditis elegans germ cell fate.
January 19, 2010 at 6:49 AM
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| | Chemical reprogramming of Caenorhabditis elegans germ cell fate. Nat Chem Biol. 2010 Feb;6(2):102-104 Authors: Morgan CT, Lee MH, Kimble J Small molecules can control cell fate in vivo and may allow directed induction of desired cell types, providing an attractive alternative to transplant-based approaches in regenerative medicine. We have chemically induced functional oocytes in Caenorhabditis elegans adults that otherwise produced only sperm. These findings suggest that chemical approaches to therapeutic cell reprogramming may be feasible and provide a powerful platform for analyzing molecular mechanisms of in vivo cell reprogramming. PMID: 20081824 [PubMed - as supplied by publisher] | | |
| A self-assembling peptide acting as an immune adjuvant.
January 19, 2010 at 6:49 AM
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| | A self-assembling peptide acting as an immune adjuvant. Proc Natl Acad Sci U S A. 2010 Jan 12;107(2):622-627 Authors: Rudra JS, Tian YF, Jung JP, Collier JH The development of vaccines and other immunotherapies has been complicated by heterogeneous antigen display and the use of incompletely defined immune adjuvants with complex mechanisms of action. We have observed strong antibody responses in mice without the coadministration of any additional adjuvant by noncovalently assembling a T and B cell epitope peptide into nanofibers using a short C-terminal peptide extension. Self-assembling peptides have been explored recently as scaffolds for tissue engineering and regenerative medicine, but our results indicate that these materials may also be useful as chemically defined adjuvants. In physiological conditions, these peptides self-assembled into long, unbranched fibrils that displayed the epitope on their surfaces. IgG1, IgG2a, and IgG3 were raised against epitope-bearing fibrils in levels similar to the epitope peptide delivered in complete Freund's adjuvant (CFA), and IgM production was even greater for the self-asse! mbled epitope. This response was dependent on self-assembly, and the self-assembling sequence was not immunogenic by itself, even when delivered in CFA. Undetectable levels of interferon-gamma, IL-2, and IL-4 in cultures of peptide-challenged splenocytes from immunized mice suggested that the antibody responses did not involve significant T cell help. PMID: 20080728 [PubMed - as supplied by publisher] | | |
| Regenerative Medicine Special Feature: Bioartificial matrices for therapeutic vascularization.
January 19, 2010 at 6:49 AM
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| | Regenerative Medicine Special Feature: Bioartificial matrices for therapeutic vascularization. Proc Natl Acad Sci U S A. 2009 Dec 31; Authors: Phelps EA, Landázuri N, Thulé PM, Taylor WR, García AJ Therapeutic vascularization remains a significant challenge in regenerative medicine applications. Whether the goal is to induce vascular growth in ischemic tissue or scale up tissue-engineered constructs, the ability to induce the growth of patent, stable vasculature is a critical obstacle. We engineered polyethylene glycol-based bioartificial hydrogel matrices presenting protease-degradable sites, cell-adhesion motifs, and growth factors to induce the growth of vasculature in vivo. Compared to injection of soluble VEGF, these matrices delivered sustained in vivo levels of VEGF over 2 weeks as the matrix degraded. When implanted subcutaneously in rats, degradable constructs containing VEGF and arginine-glycine-aspartic acid tripeptide induced a significant number of vessels to grow into the implant at 2 weeks with increasing vessel density at 4 weeks. The mechanism of enhanced vascularization is likely cell-demanded release of VEGF, as the hydrogels may degrade s! ubstantially within 2 weeks. In a mouse model of hind-limb ischemia, delivery of these matrices resulted in significantly increased rate of reperfusion. These results support the application of engineered bioartificial matrices to promote vascularization for directed regenerative therapies. PMID: 20080569 [PubMed - as supplied by publisher] | | |
| The Role of Hypoxia in Stem Cell Differentiation and Therapeutics.
January 19, 2010 at 6:49 AM
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| | The Role of Hypoxia in Stem Cell Differentiation and Therapeutics. J Surg Res. 2009 Oct 24; Authors: Abdollahi H, Harris LJ, Zhang P, McIlhenny S, Srinivas V, Tulenko T, Dimuzio PJ Stem cells differentiate into a variety of cell lines, making them attractive for tissue engineering and regenerative medicine. Specific microenvironmental cues regulate self-renewal and differentiation capabilities. Oxygen is an important component of the cellular microenvironment, serving as both metabolic substrate and signaling molecule. Oxygen has been shown to have a variety of effects on embryonic and adult stem cells. This review examines the role of hypoxia in regulating stem cell biology, specifically focusing on growth, maintenance of pluripotency, differentiation, and production of growth factors. Particular attention is paid to hypoxia and stem cells in relation to therapeutic angiogenesis. We conclude that further study is needed to optimize the use of hypoxia as a stimulus for various stem cell functions, including its potential role in therapeutic angiogenesis. PMID: 20080246 [PubMed - as supplied by publisher] | | |
| Directional differentiation of chicken spermatogonial stem cells in vitro.
January 19, 2010 at 6:49 AM
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| | Directional differentiation of chicken spermatogonial stem cells in vitro. Cytotherapy. 2010 Jan 18; Authors: Li B, Wang XY, Tian Z, Xiao XJ, Xu Q, Wei CX, F Y , Sun HC, Chen GH Abstract Background. Mammalian spermatogonial stem cells (SSC) are able to differentiate into different cell types in vitro, which are valuable sources for regenerative medicine and gene transfer studies. We investigated the differentiation potential of chicken SSC into osteoblasts, neuron-like cells and adipocytes in vitro. Methods. Chicken SSC from the testes of 18- and 20-day-old chicken embryos were cultured in different induction media for three passages in vitro. For differentiation into osteoblasts, SSC were cultured in Dulbecco's modified Eagle medium (DMEM) supplemented with 1x10(-4) micromol/mL desamethasone, 10 micromol/mL (beta-sodium glycerophosphate and 0.05 mg/mL vitamin C, and examined by microscopy after Von Kossa's, cytochemical and immunohistochemical staining. For differentiation into neuron-like cells, SSC were cultured in DMEM supplemented with 1 x 10(-3) micromol/mL retinoic acid (RA), 5.0 micromol/mL 3-isobutyl-1-methylxanthine (IBMX) and e! xamined by microscopy after toluidine blue or immunohistochemical staining. For differentiation into adipocytes, SSC were cultured in DMEM supplemented with 1 x 10(-3) micromol/mL dexamethasone, 0.01 mg/mL insulin, 0.5 micromol/mL IBMX and examined by microscopy after Oil red O staining and reverse transcriptase-polymerase chain reaction (RT-PCR) for gene expression of peroxisome proliferation activation receptor-gamma (PPAR-gamma). Results. After 15 and 21 days of culture in the induction medium for osteoblast differentiation, 75% and 80% chicken SSC differentiated into osteoblasts, as confirmed by Von Kossa's, calcium-cobalt and collagen I antibody staining. After 3 and 7 days of culture in the induction medium for neuron-like cell differentiation, 78% and 85% SSC became neuron-like cells, as confirmed by staining with toluidine blue and the monoclonal antibody against neuron-specific enolase, nestin and glial fibrillary acidic protein. After 7 days of culture in the indu! ction for adipocyte differentiation, 85% SSC differentiated in! to adipo cytes, as confirmed by Oil red O staining and RT-PCT for PPAR-gamma gene expression. Discussion. Our results show that chicken SSC can differentiate into osteoblasts, neuron-like cells and adipocytes under similar conditions as for directional differentiation of mammalian SSC in vitro. The findings show the feasibility of using SSC-derived cells for developmental biology and gene transfer studies in chickens. PMID: 20078389 [PubMed - as supplied by publisher] | | |
| CD34(+) cell selection using small-volume marrow aspirates: a platform for novel cell therapies and regenerative medicine.
January 19, 2010 at 6:49 AM
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| | CD34(+) cell selection using small-volume marrow aspirates: a platform for novel cell therapies and regenerative medicine. Cytotherapy. 2010 Jan 18; Authors: McKenna DH, Adams S, Sumstad D, Sumstad T, Kadidlo D, Gee AP, Durett A, Griffin D, Donnenberg A, Amrani D, Livingston D, Lindblad R, Wood D, Styers D Abstract Background aims. This study was initiated to determine whether CD34(+) cell selection of small-volume bone marrow (BM) samples could be performed effectively on the Isolex(R) 300i Magnetic Cell Selection System(R) device and whether the results obtained from these samples were comparable with results from large standard-volume samples. The impact on CD34(+) recovery using a full versus half vial of Isolex(R) CD34 reagent and the effects of shipping a post-selection product were evaluated. Methods. A protocol to evaluate CD34(+) cell selection with two ranges of smaller volume BM samples (c. 50 mL and c. 100 mL) was developed and instituted at three Production Assistance for Cellular Therapies (PACT) facilities. The study was performed in two phases. Results. In phase I, the mean post-selection CD34(+) recoveries from the two sizes of samples were 104.1% and 103.3% (smallest and largest volumes, respectively), and mean CD34(+) recoveries were 115.6% and 88! .7%, with full and half vials of reagent, respectively. Mean CD34(+) recoveries for post-shipment smaller volume samples were 106.8% and for larger volume samples 116.4%; mean CD34(+) recoveries were 99.9% and 127.4% for post-shipment samples processed with full and half vials of reagent, respectively. In phase II, mean CD34(+) recovery was 76.8% for post-selection samples and 74.0% for post-shipment samples. Conclusions. The results suggest that smaller volume BM sample processing on the Isolex(R) system is as efficient or more efficient compared with standard-volume sample processing. Post-processing mean CD34(+) recovery results obtained using a full or half vial of CD34 reagent were not significantly different. PMID: 20078385 [PubMed - as supplied by publisher] | | |
| Developments in clinical cell therapy.
January 19, 2010 at 6:49 AM
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| | Developments in clinical cell therapy. Cytotherapy. 2010 Jan 18; Authors: Stroncek D, Berlyne D, Fox B, Gee A, Heimfeld S, Lindblad R, Loper K, McKenna D, Rooney C, Sabatino M, Wagner E, Whiteside T, Wood D, Heath-Mondoro T Abstract Immunotherapy has become an important part of hematopoietic stem cell (HSC) transplantation and cancer therapy. Regenerative and reparative properties of somatic cell-based therapies hold tremendous promise for repairing injured tissue, preventing and reversing damage to organs, and restoring balance to compromised immune systems. The principles and practices of the diverse aspects of immune therapy for cancer, HSC transplantation and regenerative medicine have many commonalities. This meeting report summarizes a workshop sponsored by the National Heart, Lung and Blood Institute (NHLBI) and Production Assistance for Cellular Therapies (PACT), held on 23-24 April 2009 at the National Institutes of Health (NIH, USA). A series of scientific sessions and speakers highlighted key aspects of the latest scientific, clinical and technologic developments in cell therapy, involving a unique set of cell products with a special emphasis on converging concepts in thes! e fields. PMID: 20078383 [PubMed - as supplied by publisher] | | |
| Platelet-derived growth factor receptors regulate mesenchymal stem cell fate: implications for neovascularization.
January 19, 2010 at 6:49 AM
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| | Platelet-derived growth factor receptors regulate mesenchymal stem cell fate: implications for neovascularization. Expert Opin Biol Ther. 2010 Jan;10(1):57-71 Authors: Ball SG, Shuttleworth CA, Kielty CM Importance of the field: Regulating stem cell contributions to vascularization is a challenging goal, but a fundamental aspect of regenerative medicine. Human mesenchymal stem cells retain considerable potential for adult vascular repair and regeneration therapies. They are readily obtained, rapidly proliferate in culture, display a capacity to differentiate towards endothelial or vascular smooth muscle cells, and play an important role in postnatal neovascularization in various tissue contexts. To therapeutically enhance neovascularization during ischemic disease, or inhibit neovascularization during tumorigenesis, an essential prerequisite is to determine the mechanisms which control the recruitment and differentiation of mesenchymal stem cells towards vascular cells. Areas covered in this review: In this review, we describe the current understanding of how PDGF receptors contribute prominently to neovascularization, and play a decisive role in modulating mesenc! hymal stem cell recruitment and differentiation towards vascular cells. We discuss PDGF receptor-based therapeutic strategies to exploit mesenchymal stem cells during vascular repair and regeneration, and to control pathological neovascularization. Take home message: PDGF receptor signaling is emerging as a critical regulatory mechanism and important therapeutic target, that critically directs the fate of mesenchymal stem cells during postnatal neovascularization. PMID: 20078229 [PubMed - as supplied by publisher] | | |
| A reprogrammable mouse strain from gene-targeted embryonic stem cells.
January 19, 2010 at 6:49 AM
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| | A reprogrammable mouse strain from gene-targeted embryonic stem cells. Nat Methods. 2010 Jan;7(1):53-5 Authors: Stadtfeld M, Maherali N, Borkent M, Hochedlinger K The derivation of induced pluripotent stem cells (iPSCs) usually involves the viral introduction of reprogramming factors into somatic cells. Here we used gene targeting to generate a mouse strain with a single copy of an inducible, polycistronic reprogramming cassette, allowing for the induction of pluripotency in various somatic cell types. As these 'reprogrammable mice' can be easily bred, they are a useful tool to study the mechanisms underlying cellular reprogramming. PMID: 20010832 [PubMed - indexed for MEDLINE] | | |
| Neurogenic-committed human pre-adipocytes express cyp1a isoforms.
January 19, 2010 at 6:15 AM
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| | Neurogenic-committed human pre-adipocytes express cyp1a isoforms. Chem Biol Interact. 2010 Jan 14; Authors: Chiara S, Maria BA, Mariafrancesca C, Chiara G, Rosella C, Carla F, Mariagrazia A, Pierluigi S, Edoardo R Stem cell models offer an opportunity both for therapeutic use and for the assessment of alternative in vitro models. Human lipoaspirate is a source of adult stem cells (pre-adipocytes), which are able to differentiate into various phenotypes, such as neurogenic lineage. Here, we analyse the suitability of these in vitro models in screening exogenous compounds, such as environmental pollutants, that may affect adipose cells and neurogenic development. To evaluate neurogenic differentiation, we analysed expression of cholinergic system and acetylcholinesterase immunoreactivity Heterocyclic derivatives of polycyclic aromatic hydrocarbons (PAH) are often significant components of environmental contaminants. As they contain inducers of cytochrome P450 1A1 (CYP1A1), we explored the activity of CYP1A1-related enzymes, i.e. 7-ethoxycoumarin- and 7-ethoxyresorufin O- deethylase (ECOD and EROD) in both cell systems in basal conditions and after exposure to non-cytotoxic do! ses of beta-naphthoflavone (BNF), a well known PAH-type inducer. Both cell models showed basal and inducible levels of ECOD. Analysis of CYP1A1 protein expression and EROD-related enzyme activity confirmed the inducibility of the CYP1A1 isoform by BNF. These results demonstrate that mesenchymal adult stem cells can constitute innovative models. We therefore propose the use of pre-adipocytes and their neurogenic derivates to evaluate the cytotoxic/biological effects of unintended exposure to contaminants. PMID: 20080079 [PubMed - as supplied by publisher] | | |
| Highly efficient gene transfer system using a laminin-DNA-apatite composite layer.
January 19, 2010 at 6:10 AM
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| | Highly efficient gene transfer system using a laminin-DNA-apatite composite layer. J Gene Med. 2010 Jan 15; Authors: Oyane A, Tsurushima H, Ito A BACKGROUND: We have recently developed a safe and efficient gene transfer system using a laminin-DNA-apatite composite layer. The objectives of the present study were to fully characterize and optimize the laminin-DNA-apatite composite layer in relation to the efficiency of gene transfer and to demonstrate the feasibility of the composite layer in the induction of cell differentiation. METHODS: The laminin-DNA-apatite composite layer was prepared under various conditions. The efficiency of gene transfer on the resulting composite layer was evaluated using luciferase and ss-galactosidase gene expression assay systems. A laminin-DNA-apatite composite layer, prepared under the optimized condition using a plasmid including cDNA of nerve growth factor (NGF), was then applied to the neuron-like differentiation of PC12 cells. RESULTS: The laminin content of the laminin-DNA-apatite composite layer was found to be a dominant factor improving the efficiency of gene transfer! rather than the DNA content. The cell adhesion property of laminin in the composite layer should be responsible for the improvement in efficiency of gene transfer because the immobilization of albumin without the cell adhesion property in a DNA-apatite composite layer had no effect on the efficiency of gene transfer. A laminin-DNA-apatite composite layer, prepared under the optimized condition using a plasmid including cDNA of NGF, successfully induced the neuron-like differentiation of PC12 cells. CONCLUSIONS: The present gene transfer system, with the potential to control cell differentiation and having features of safety and relatively high and controllable efficiency, would be a useful tool for tissue engineering applications and the production of transfection microarrays. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20082421 [PubMed - as supplied by publisher] | | |
| [Combined cell transplant based upon autologic multipotent stromal cells of adipose tissue use in patients with distinct deficit of bone tissue in maxillae region.]
January 19, 2010 at 6:10 AM
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| | [Combined cell transplant based upon autologic multipotent stromal cells of adipose tissue use in patients with distinct deficit of bone tissue in maxillae region.] Stomatologiia (Mosk). 2009;88(6):32-34 Authors: Alekseeva IS, Arutiunian3 IV, Volkov2 AV, Shuraev AI Use of synthetic osteoplastic materials not always leads to formation of the necessary bone tissue volume. The alternative high technological implantation material can become tissue engineering constructions containing osteogenic precursor cells. Clinical observation of sinus lifting with the use of tissue engineering construction demonstrates the efficacy, shortening the terms of operation wound healing, young bone tissue formation after transplantation and possibility to install implants already after 3 months if the amount of bone is sufficient for primary fixation. PMID: 20081777 [PubMed - as supplied by publisher] | | |
| Tissue-Engineered Heart Valve Scaffolds.
January 19, 2010 at 6:10 AM
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| | Tissue-Engineered Heart Valve Scaffolds. Ann Thorac Cardiovasc Surg. 2009 Aug;15(6):362-367 Authors: Dohmen PM, Konertz W Since the first heterotopic implanted biological heart valve in 1956 by Murray, many improvements have been made. For allografts, different methods have been evaluated and modified to stabilize and preserve tissue. Xenografts were fixated to cross-link the connective tissue and to overcome immunogenic reactions. Nevertheless, glutaraldehyde fixation leads to structural deterioration, which can be partially reduced by different kinds of antimineralization treatments. Because of preservation and fixation, allografts and xenografts become nonviable bioprostheses with a lack of remodeling, regeneration, and growth. Tissue engineering is a possible key to overcome these disadvantages because it will provide a living tissue with remodeling, regeneration, and growth potential. This overview will issue the key points to provide such a tissue-engineered heart valve by creating a sufficient scaffold where cells can grow, either in vitro or in vivo, and remodel a neoscaffold! that will lead to a functional autologous heart valve. PMID: 20081743 [PubMed - as supplied by publisher] | | |
| A self-assembling peptide acting as an immune adjuvant.
January 19, 2010 at 6:10 AM
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| | A self-assembling peptide acting as an immune adjuvant. Proc Natl Acad Sci U S A. 2010 Jan 12;107(2):622-627 Authors: Rudra JS, Tian YF, Jung JP, Collier JH The development of vaccines and other immunotherapies has been complicated by heterogeneous antigen display and the use of incompletely defined immune adjuvants with complex mechanisms of action. We have observed strong antibody responses in mice without the coadministration of any additional adjuvant by noncovalently assembling a T and B cell epitope peptide into nanofibers using a short C-terminal peptide extension. Self-assembling peptides have been explored recently as scaffolds for tissue engineering and regenerative medicine, but our results indicate that these materials may also be useful as chemically defined adjuvants. In physiological conditions, these peptides self-assembled into long, unbranched fibrils that displayed the epitope on their surfaces. IgG1, IgG2a, and IgG3 were raised against epitope-bearing fibrils in levels similar to the epitope peptide delivered in complete Freund's adjuvant (CFA), and IgM production was even greater for the self-asse! mbled epitope. This response was dependent on self-assembly, and the self-assembling sequence was not immunogenic by itself, even when delivered in CFA. Undetectable levels of interferon-gamma, IL-2, and IL-4 in cultures of peptide-challenged splenocytes from immunized mice suggested that the antibody responses did not involve significant T cell help. PMID: 20080728 [PubMed - as supplied by publisher] | | |
| Fibrin concentration affects ACL fibroblast proliferation and collagen synthesis.
January 19, 2010 at 6:10 AM
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| | Fibrin concentration affects ACL fibroblast proliferation and collagen synthesis. Knee. 2010 Jan 15; Authors: Vavken P, Joshi SM, Murray MM Fibrin is a frequently used biomaterial in surgery and tissue engineering. While it has been shown that fibrin supports cellular proliferation and biosynthesis, there is a scarcity of studies focusing on the effects of fibrin concentration. The objective of this study is to assess the effect of fibrin concentrations around the physiological concentration of 3mg/ml on the behavior of ligament fibroblasts. Fibroblasts were obtained from the anterior cruciate ligaments of four pigs and seeded throughout fibrin gels of either 1, 3, or 6mg/ml fibrin. The gels were collected at 2, 6, and 10days for measurement of DNA and collagen content. We found that both DNA and collagen content increased significantly over time in gels made with all concentrations of fibrin. However, the increases were significantly lower in gels made with the higher concentrations of fibrin (3 and 6mg/ml). Microscopic assessment of FITC-labeled gels showed a decrease in pore size at high fibrin con! centrations, which might be a reason for the observed effect on bioactivity. To enhance cell behavior and thus clinical results fibrin applications should build on physiologic or sub-physiologic concentrations, and those with higher concentrations, such as currently available sealants, should be used cautiously. PMID: 20080411 [PubMed - as supplied by publisher] | | | |
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