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| The competitive adsorption of human proteins onto natural-based biomaterials.
February 26, 2010 at 7:58 AM
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| | The competitive adsorption of human proteins onto natural-based biomaterials. J R Soc Interface. 2010 Feb 24; Authors: Alves CM, Reis RL, Hunt JA This study aims to further the understanding of nanoscale structures relevant for cellular recognition on contact and interaction with natural-based materials. The correlation between surface characteristics and protein adsorption from unitary and complex protein systems was investigated with respect to altering the bulk chemistry of the substrate material. Polymeric blends of starch and cellulose acetate, polycaprolactone (SPCL) and ethylene vinyl alcohol (SEVA-C) were used. Different proteins, bovine serum albumin, human serum albumin (HSA) and human fibronectin (HFN), were selected for this study. The construction of adsorption isotherms is an important starting point towards characterizing the interactions between surfaces and proteins. In this study, albumin adsorption isotherms fit the Freundlich model and were correlated with the chemistry and morphology of surfaces. In addition, protein distribution, quantification and competition were measured using fluor! imetry and visualized by confocal microscopy. The analysis of unitary systems demonstrated that the adsorption of HSA was generally lower than that of HFN. In the latter case, SPCL and SEVA-C blends reached adsorption values of 97 and 89 per cent, respectively. In studying the co-adsorption of proteins, an increase in both HSA and HFN on SEVA-C surfaces was observed. SPCL showed no substantial increase in the adsorption of the proteins in competitive conditions. The similarity of these materials with other polysaccharide-based materials increases the relevance of the presented results. This study provides valuable information for the development of strategies towards the control of protein orientation and functionality as the availability of cell signalling epitopes for a broader family of materials that continue to be a significant component of this field of research. PMID: 20181561 [PubMed - as supplied by publisher] | | |
| Photodynamic therapy of fullerene modified with pullulan on hepatoma cells.
February 26, 2010 at 7:58 AM
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| | Photodynamic therapy of fullerene modified with pullulan on hepatoma cells. J Drug Target. 2010 Feb 25; Authors: Liu J, Tabata Y To design a novel cytospecific photosensitizer for photodynamic antitumor therapy, a fullerene (C(60)) was chemically modified with pullulan which is a water-soluble polysaccharide with a high affinity for asialoglycoprotein receptors. Ethylene diamine was introduced to the terminal aldehyde groups of pullulan by the reductive amination reaction. Pullulan was coupled to C(60) through the terminal amine group. The C(60) end-group conjugated with pullulan was water-soluble and generated superoxide anion upon light irradiation. The C(60)-pullulan conjugates significantly suppressed the in vitro growth of HepG2 hepatoma cells with asialoglycoprotein receptors, while less suppression activity was observed for HeLa cells without the receptors. The conjugates have a high binding affinity for HepG2 cells, in contrast to HeLa cells. When C(60) was conjugated with polyethylene glycol (PEG) with the similar molecular weight in order to compare the in vitro cell binding and a! ntitumor activities with the C(60)-pullulan conjugate, the dependence of cell type on their activities was not observed. Following the intravenous injection of C(60)-pullulan conjugates to mice carrying a subcutaneous mass of HepG2 cells, significant stronger photodynamic effect on tumor was observed than the intravenous injection of C(60)-PEG conjugates and saline. It is concluded that the pullulan conjugation gave C(60) the targetability to HepG2 cells, resulting in enhanced photodynamic tumor therapy effect. PMID: 20180750 [PubMed - as supplied by publisher] | | |
| Geometrically controlled endothelial tubulogenesis in micropatterned gels.
February 26, 2010 at 7:58 AM
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| | Geometrically controlled endothelial tubulogenesis in micropatterned gels. Tissue Eng Part A. 2010 Feb 24; Authors: Raghavan S, Nelson CM, Baranski J, Lim E, Chen CS We present a novel approach to control endothelial tubulogenesis by spatially patterning cells within micromolded collagen gels. Endothelial cells cultured within microscale channels filled with collagen gel organized into tubes with lumens within 24 - 48 hours of seeding. These tubes extended up to one centimeter in length, and exhibited cell-cell junction formation characteristic of early stage capillary vessels. Tube diameter could be controlled by varying collagen concentrations or channel width. The geometry of the microfabricated template also could be used to guide the development of branches during tube formation, allowing for the generation of more complex capillary architectures. Time-lapse imaging of tube formation revealed a highly dynamic process involving coalescence of endothelial cells, reorganization and alignment of collagen fibers into a central core, and arrangement of cells into cords. This platform may be of use to generate geometrically defi! ned vascular networks for tissue engineering applications as well as a means to better understand the process of endothelial tubulogenesis. PMID: 20180698 [PubMed - as supplied by publisher] | | |
| Vacuum-Assisted Cell Seeding in a Microwell Cell Culture System.
February 26, 2010 at 7:58 AM
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| | Vacuum-Assisted Cell Seeding in a Microwell Cell Culture System. Anal Chem. 2010 Feb 24; Authors: Ferrell N, Gallego-Perez D, Higuita-Castro N, Butler RT, Reen RK, Gooch KJ, Hansford DJ We present a simple method to actively pattern individual cells and groups of cells in a polymer-based microdevice using vacuum-assisted cell seeding. Soft lithography is used to mold polymer microwells with various geometries on top of commercially available porous membranes. Cell suspensions are placed in a vacuum filtration setup to pull culture medium through the microdevice, trapping the cells in the microwells. The process is evaluated by determining the number of cells per microwell for a given cell seeding density and microwell geometry. This method is tested with adherent and nonadherent cells (NIH 3T3 fibroblasts, PANC-1 pancreatic ductal epithelial-like cells, and THP-1 monocytic leukemia cells). These devices could find applications in high-throughput cell screening, cell transport studies, guided formation of cell clusters, and tissue engineering. PMID: 20180539 [PubMed - as supplied by publisher] | | |
| The use of silk fibroin/hydroxyapatite composite co-cultured with rabbit bone-marrow stromal cells in the healing of a segmental bone defect.
February 26, 2010 at 7:58 AM
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| | The use of silk fibroin/hydroxyapatite composite co-cultured with rabbit bone-marrow stromal cells in the healing of a segmental bone defect. J Bone Joint Surg Br. 2010 Feb;92(2):320-5 Authors: Wang G, Yang H, Li M, Lu S, Chen X, Cai X In a rabbit model we investigated the efficacy of a silk fibroin/hydroxyapatite (SF/HA) composite on the repair of a segmental bone defect. Four types of porous SF/HA composites (SF/HA-1, SF/HA-2, SF/HA-3, SF/HA-4) with different material ratios, pore sizes, porosity and additives were implanted subcutaneously into Sprague-Dawley rats to observe biodegradation. SF/HA-3, which had characteristics more suitable for a bone substitute based on strength and resorption was selected as a scaffold and co-cultured with rabbit bone-marrow stromal cells (BMSCs). A segmental bone defect was created in the rabbit radius. The animals were randomised into group 1 (SF/HA-3 combined with BMSCs implanted into the bone defect), group 2 (SF/HA implanted alone) and group 3 (nothing implanted). They were killed at four, eight and 12 weeks for visual, radiological and histological study. The bone defects had complete union for group 1 and partial union in group 2, 12 weeks after operati! on. There was no formation of new bone in group 3. We conclude that SF/HA-3 combined with BMSCs supports bone healing and offers potential as a bone-graft substitute. PMID: 20130332 [PubMed - indexed for MEDLINE] | | |
| Controlling destiny through chemistry: small-molecule regulators of cell fate.
February 26, 2010 at 7:58 AM
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| | Controlling destiny through chemistry: small-molecule regulators of cell fate. ACS Chem Biol. 2010 Jan 15;5(1):15-34 Authors: Firestone AJ, Chen JK Controlling cell fate is essential for embryonic development, tissue regeneration, and the prevention of human disease. With each cell in the human body sharing a common genome, achieving the appropriate spectrum of stem cells and their differentiated lineages requires the selective activation of developmental signaling pathways, the expression of specific target genes, and the maintenance of these cellular states through epigenetic mechanisms. Small molecules that target these regulatory processes are therefore valuable tools for probing and manipulating the molecular mechanisms by which stem cells self-renew, differentiate, and arise from somatic cell reprogramming. Pharmacological modulators of cell fate could also help remediate human diseases caused by dysregulated cell proliferation or differentiation, heralding a new era in molecular therapeutics. PMID: 20000447 [PubMed - indexed for MEDLINE] | | |
| Neuroprotective effect of oligodendrocyte precursor cell transplantation in a long-term model of periventricular leukomalacia.
February 26, 2010 at 7:58 AM
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| | Neuroprotective effect of oligodendrocyte precursor cell transplantation in a long-term model of periventricular leukomalacia. Am J Pathol. 2009 Dec;175(6):2332-42 Authors: Webber DJ, van Blitterswijk M, Chandran S Perinatal white matter injury, or periventricular leukomalacia (PVL), is the most common cause of brain injury in premature infants and is the leading cause of cerebral palsy. Despite increasing numbers of surviving extreme premature infants and associated long-term neurological morbidity, our understanding and treatment of PVL remains incomplete. Inflammation- or ischemia/hypoxia-based rodent models, although immensely valuable, are largely restricted to reproducing short-term features of up to 3 weeks after injury. Given the long-term sequelae of PVL, there is a need for subchronic models that will enable testing of putative neuroprotective therapies. Here, we report long term characterization of a neonatal inflammation-induced rat model of PVL. We show bilateral ventriculomegaly, inflammation, reactive astrogliosis, injury to pre-oligodendrocytes, and neuronal loss 8 weeks after injury. We demonstrate neuroprotective effects of oligodendrocyte precursor cell tr! ansplantation. Our findings present a subchronic model of PVL and highlight the tissue protective effects of oligodendrocyte precursor cell transplants that demonstrate the potential of cell-based therapy for PVL. PMID: 19850891 [PubMed - indexed for MEDLINE] | | |
| Impact of diabetes and obesity on the prostate and urethra: implications to improved bladder dysfunction understanding and treatment.
February 26, 2010 at 7:58 AM
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| | Impact of diabetes and obesity on the prostate and urethra: implications to improved bladder dysfunction understanding and treatment. J Urol. 2009 Dec;182(6 Suppl):S38-44 Authors: Christ GJ, Bushman W, Fraser MO PURPOSE: Alterations in bladder function are well documented in response to diabetes and obesity. Nonetheless, clinical manifestations of bladder dysfunction are diverse and the efficacy of available therapy is suboptimal. Since the bladder is only 1 component of the lower urinary tract, we explored existing evidence for the potential contribution(s) of other major lower urinary tract structures to diabetes and obesity related bladder dysfunction, namely the prostate and the urethra. MATERIALS AND METHODS: We performed a MEDLINE database search of the relevant literature. RESULTS: A relatively large literature exists on bladder dysfunction and the urethra. However, when additional search terms were added, such as prostate, diabetes and obesity, there was a dramatic decrease in the number of retrieved citations. These observations are consistent with the vanishingly small available literature on the impact of diabetes on prostatic biology and urethral function, and! their potential impact on bladder physiology/dysfunction. The available literature documents significant alterations in prostatic biology and urethral function in the setting of diabetes and/or obesity. CONCLUSIONS: The observed diversity in diabetes and obesity related bladder dysfunction, and the variable efficacy of currently available treatments may be related at least in part to the differential impact of these disease states on the complex integration of bladder function with other structural components of the lower urinary tract, namely the urethra and the prostate. More comprehensive investigations of this system should lead to improved understanding of the mechanistic basis for the observed pathophysiology and identify novel treatment regimens. PMID: 19846131 [PubMed - indexed for MEDLINE] | | |
| Marrow stromal fibroblastic cell cultivation in vitro on decellularized bone marrow extracellular matrix.
February 26, 2010 at 7:58 AM
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| | Marrow stromal fibroblastic cell cultivation in vitro on decellularized bone marrow extracellular matrix. Exp Mol Pathol. 2010 Feb;88(1):58-66 Authors: Dutra TF, French SW The in vitro biocompatibility of decellularized bone marrow extracellular matrix was evaluated. Following a freeze-thaw cycle, sectioned discs of fresh frozen rat metaphyseal bone were sequentially incubated in solutions of hypertonic, then hypotonic Ringer's solution, followed by deoxycholic acid, then DNAase I. The adequacy of decellularization of marrow stroma was examined by light microscopy. Marrow stromal fibroblastic cells were harvested by dispersion of rat long bone marrow, followed by concentration by discontinuous Ficoll-Paque gradient centrifugation. The fibroblastic cells were expanded by in vitro cultivation, and second passage cells were cryopreserved until needed. Cryopreserved marrow stromal cells were applied dropwise to sections of decellularized bone marrow extracellular matrix, and cultured in BJGb medium with 20% fetal bovine serum for ten days. Mature cultures were formalin fixed, decalcified, and embedded in paraffin. Light microscopy of he! matoxylin and eosin stained sections showed individual spindle cells invading the upper portion of the decellularized extracellular matrix, and also a monolayer of spindle cells on the upper surfaces of exposed trabecular and cortical bone. This experiment showed that decellularized marrow extracellular matrix is a biocompatible three dimensional in vitro substrate for marrow stromal fibroblastic cells. PMID: 19778536 [PubMed - indexed for MEDLINE] | | |
| Osteogenesis of the construct combined BMSCs with beta-TCP in rat.
February 26, 2010 at 7:58 AM
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| | Osteogenesis of the construct combined BMSCs with beta-TCP in rat. J Plast Reconstr Aesthet Surg. 2010 Feb;63(2):227-32 Authors: Zhang M, Wang K, Shi Z, Yang H, Dang X, Wang W BACKGROUND: The use of artificial bone graft substitutes has increased as the surgical applications widen and the availability of allograft bone decreases. The present study was to evaluate the construct combined bone marrow stromal cells (BMSCs) with beta-tricalcium phosphate (beta-TCP) as bone substitute implanted in rat dorsal muscles. METHODS: To study the osteogenic capability in vivo, specimens were harvested on 1 week, 4 weeks and 8 weeks after implantation, and were analyzed by hematoxylin and eosin (HE) staining. The percentages of new bone formation for each implant type and implantation period were determined by histomorphometry. RESULTS: After 1 week of implantation, new bone formation for both beta-TCP and BMSCs+beta-TCP group had no formed. After 4 weeks of implantation, the amount of bone formation was increased to 1.32 % in beta-TCP group and 6.35% in BMSCs+beta-TCP group. After 8 weeks of implantation, more bone was found in the BMSCs+beta-TCP gro! up (21.58 %), while in the beta-TCP group bone formation was increased to 4.78%. Significant differences between the two groups have been observed. CONCLUSIONS: Based on these results, we conclude that bone substitutes constructed by porous beta-TCP scaffold loaded with osteogenically induced BMSCs could promote newly formed bone. PMID: 19091642 [PubMed - indexed for MEDLINE] | | |
| Outgrowth Endothelial Cells: Sources, Characteristics and Potential Applications in Tissue Engineering and Regenerative Medicine.
February 26, 2010 at 7:58 AM
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| | Outgrowth Endothelial Cells: Sources, Characteristics and Potential Applications in Tissue Engineering and Regenerative Medicine. Adv Biochem Eng Biotechnol. 2010 Feb 18; Authors: Fuchs S, Dohle E, Kolbe M, Kirkpatrick CJ Endothelial progenitor cells from peripheral blood or cord blood are attracting increasing interest as a potential cell source for cellular therapies aiming to enhance the neovascularization of tissue engineered constructs or ischemic tissues. The present review focus on a specific population contained in endothelial progenitor cell cultures designated as outgrowth endothelial cells (OEC) or endothelial colony forming cells from peripheral blood or cord blood. Special attention will be paid to what is currently known in terms of the origin and the cell biological or functional characteristics of OEC. Furthermore, we will discuss current concepts, how OEC might be integrated in complex tissue engineered constructs based on biomaterial or co-cultures, with special emphasis on their potential application in bone tissue engineering and related vascularization strategies. PMID: 20182927 [PubMed - as supplied by publisher] | | |
| Engineering of aligned skeletal muscle by micropatterning.
February 26, 2010 at 7:58 AM
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| | Engineering of aligned skeletal muscle by micropatterning. Am J Transl Res. 2010;2(1):43-55 Authors: Huang NF, Lee RJ, Li S Tissue engineered skeletal muscle has tremendous potential for the treatment of muscular injury or muscular dysfunction. However, in vitro methods to generate skeletal muscle with physiologically aligned myofiber structure remains limited. To develop a robust in vitro model that resembles the physiologically aligned structure of muscle fibers, we fabricated micropatterned polymer membranes of poly(dimethylsiloxane) (PDMS) with parallel microgrooves, and then examined the effect of micropatterning on myoblast cellular organization and the cell fusion process. In comparison to the myoblasts on non-patterned PDMS films, myoblasts on micropatterned PDMS films had well-organized F-actin assembly in close proximity to the direction of microgrooves, along with enhanced levels of myotube formation at early time points. The increase of cell cycle regulator p21(WAF/Cip1) and the organized interactions of N-cadherin in myoblasts on micropatterned surfaces may contribute to t! he enhanced formation of myotubes. Similar results of cellular alignment was observed when myoblasts were cultured on microfluidically patterned poly(2-hydroxyethyl methacrylate) (pHEMA) microgrooves, and the micropatterns were found to detach from the Petri dish over time. To apply this technology for generating aligned tissue-like muscle constructs, we developed a methodology to transfer the aligned myotubes to biodegradable collagen gels. Histological analysis revealed the persistence of aligned cellular organization in the collagen gels. Together, these results demonstrate that micropatterned PDMS or pHEMA can promote cell alignment and fusion along the direction of the microgrooves, and this platform can be utilized to transfer aligned myotubes on biodegradable hydrogels. This study highlights the importance of spatial cues in creating aligned skeletal muscle for tissue engineering and muscular regeneration applications. PMID: 20182581 [PubMed - in process] | | |
| Epidermal Growth Factor (EGF) Treatment on Multipotential Stromal Cells (MSCs). Possible Enhancement of Therapeutic Potential of MSC.
February 26, 2010 at 7:58 AM
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| | Epidermal Growth Factor (EGF) Treatment on Multipotential Stromal Cells (MSCs). Possible Enhancement of Therapeutic Potential of MSC. J Biomed Biotechnol. 2010;2010:795385 Authors: Tamama K, Kawasaki H, Wells A Adult bone marrow multipotential stromal cells (MSCs) hold great promise in regenerative medicine and tissue engineering. However, due to their low numbers upon harvesting, MSCs need to be expanded in vitro without biasing future differentiation for optimal utility. In this concept paper, we focus on the potential use of epidermal growth factor (EGF), prototypal growth factor for enhancing the harvesting and/or differentiation of MSCs. Soluble EGF was shown to augment MSC proliferation while preserving early progenitors within MSC population, and thus did not induce differentiation. However, tethered form of EGF was shown to promote osteogenic differentiation. Soluble EGF was also shown to increase paracrine secretions including VEGF and HGF from MSC. Thus, soluble EGF can be used not only to expand MSC in vitro, but also to enhance paracrine secretion through drug-releasing MSC-encapsulated scaffolds in vivo. Tethered EGF can also be utilized to direct MSC toward! s osteogenic lineage both in vitro and in vivo. PMID: 20182548 [PubMed - in process] | | | | 
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