|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | Suspension of California bond sales because of the state's budget crisis will not have an "immediate impact" on the state's stem cell agency, whose only real source of cash is state bonds.
James Harrison, outside counsel for the CIRM board, said that the agency "has cash reserves to cover its current needs and it does not need to issue bonds in the spring." As recently as December, other CIRM | | | | | | | | | | | | | | | | | | | | | | | | The state of California, dogged by a mammoth financial crisis, is postponing the sale of state bonds this year, raising questions about the move's impact on the state's stem cell research effort, which is funded solely through the borrowed money.
State Treasurer Bill Lockyer said yesterday the delay in selling state bonds until later this year would save the state $248 million. It would be the | | | | | | | | | | | | | | | | | | | | | | | | | Distinct phenotypes and regenerative potentials of early endothelial progenitor cells and outgrowth endothelial progenitor cells derived from umbilical cord blood. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Reagan J, Foo T, Tracy Watson J, Jin W, Moed BR, Zhang Z The capability of postnatal neovascularization makes circulating endothelial progenitor cells (EPCs) promising for regenerative medicine and tissue engineering. Using EPCs isolated from umbilical cord blood, this study aimed to clarify the transition of functional properties from early EPCs (e-EPCs) to outgrowth EPCs (og-EPCs) for potential applications in regenerative medicine. Mononuclear cells were collected from umbilical cord blood via density gradient centrifugation and further negatively selected by CD45. EPCs were sorted from mononuclear cells by the expression of CD34. e-EPCs (7 days of culture) and og-EPCs (3 weeks of culture) were characterized by morphology, intake of acetylated low-density lipoprotein, vessel-cord formation, cell surface phenotype and the expression of angiogenic genes. e-EPCs and og-EPCs were also compared for osteogenic differentiation under the stimulation of BMP-2. Chemotaxis by SDF-1 was compared among og-EPCs and the first- and second-day attached e-EPCs. Based on the expression of angiogenic genes, e-EPCs possessed few angiogenic properties in vitro and og-EPCs were angiogenic. e-EPCs, however, expressed significant CXCR4 and migrated toward the SDF-1 gradient. og-ECPs did not express CXCR4 and showed no response to SDF-1. During culture, gaining an angiogenic phenotype by og-EPCs is associated with the loss of homing potential. These contrast properties determine different potentials of e-EPCs and og-EPCs in regenerative medicine. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21218468 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A molecular dynamic analysis of gelatin as an amorphous material: Prediction of mechanical properties of gelatin systems. Int J Artif Organs. 2010 Nov 23; Authors: Zaupa A, Neffe AT, Pierce BF, Lendlein A, Hofmann D Biomaterials are used in regenerative medicine for induced autoregeneration and tissue engineering. This is often challenging, however, due to difficulties in tailoring and controlling the respective material properties. Since functionalization is expected to offer better control, in this study gelatin chains were modified with physically interacting groups based on tyrosine with the aim of causing the formation of physical crosslinks. This method permits application-specific properties like swelling and better tailoring of mechanical properties. The design of the crosslink strategy was supported by molecular dynamic (MD) simulations of amorphous bulk models for gelatin and functionalized gelatins at different water contents (0.8 and 25 wt.-%). The results permitted predictions to be formulated about the expected crosslink density and its influence on equilibrium swelling behavior and on elastic material properties. The models of pure gelatin were used to validate the strategy by comparison between simulated and experimental data such as density, backbone conformation angle distribution, and X-ray scattering spectra. A key result of the simulations was the prediction that increasing the number of aromatic functions attached to the gelatin chain leads to an increase in the number of physical netpoints observed in the simulated bulk packing models. By comparison with the Flory-Rehner model, this suggested reduced equilibrium swelling of the functionalized materials in water, a prediction that was subsequently confirmed by our experimental work. The reduction and control of the equilibrium degree of swelling in water is a key criterion for the applicability of functionalized gelatins when used, for example, as matrices for induced autoregeneration of tissues. PMID: 21218393 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Embryonic stem cell application in drug discovery. Acta Pharmacol Sin. 2011 Jan 10; Authors: Lou YJ, Liang XG Embryonic stem (ES) cells and their differentiated progeny offer tremendous potential for regenerative medicine, even in the field of drug discovery. There is an urgent need for clinically relevant assays that make use of ES cells because of their rich biological utility. Attention has been focused on small molecules that allow the precise manipulation of cells in vitro, which could allow researchers to obtain homogeneous cell types for cell-based therapies and discover drugs for stimulating the regeneration of endogenous cells. Such therapeutics can act on target cells or their niches in vivo to promote cell survival, proliferation, differentiation, and homing. In the present paper, we reviewed the use of ES cell models for high-throughput/content drug screening and toxicity assessment. In addition, we examined the role of stem cells in large pharmaceutical companies' R&D and discussed a novel subject, nicheology, in stem cell-related research fields. PMID: 21217770 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Dendritic cells in networks of immunological tolerance. Tissue Antigens. 2011 Feb;77(2):89-99 Authors: Gregori S Dendritic cells (DC) represent pacemakers of the immune system because they play a major role as antigen-presenting cells in inducing adaptive immune responses on the one hand and are critically involved in promoting and maintaining immunological tolerance on the other. The latter function is mediated by specialized subsets of DC, named tolerogenic DC, as well as by DC activated or differentiated in the presence of specific biological or chemical agents. Suppression by tolerogenic DC is primarily mediated via the induction of regulatory T (Tr) cells. In the present review, we will focus on human tolerogenic DC with the aim to: (1) describe subsets of human tolerogenic DC; (2) define the modes of in vitro induction of myeloid tolerogenic DC and their ability to induce Tr cells; (3) elucidate the role of tolerogenic DC in orchestrating tolerance induction in vivo; and (4) envisage the use of tolerogenic DC as therapeutic tool to trigger immunoregulatory mechanisms. PMID: 21214520 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Induction of mesenchymal to endothelial transformation of adipose-derived stem cells. J Heart Valve Dis. 2010 Nov;19(6):736-44 Authors: Colazzo F, Chester AH, Taylor PM, Yacoub MH Adipose tissue is a readily available source of multipotent adult stem cells for use in tissue engineering and regenerative medicine. Adipose-derived stem cells (ADSCs) are currently being investigated as a source of interstitial cells to populate tissue-engineered heart valve constructs. However, the ability of these cells to differentiate into endothelial cells that would be required to cover the surface of the valve cusps has not been fully investigated. PMID: 21214098 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Concise Review: Human Adipose-Derived Stem Cells (ASC): Separating Promise from Clinical Need. Stem Cells. 2011 Jan 7; Authors: Locke M, Feisst V, Dunbar PR Human ASC have become of increasing interest to both stem cell biologists and clinicians because of their potential to differentiate into adipogenic, osteogenic, chondrogenic and other mesenchymal lineages, as well as other clinically useful properties attributed to them, such as stimulation of angiogenesis and suppression of inflammation. ASC have already been used in a number of clinical trials, and some successful outcomes have been reported, especially in tissue reconstruction. However a critical review of the literature reveals considerable uncertainty about the true clinical potential of human ASC. Firstly, the surgical needs that ASC might answer remain relatively few, given the current difficulties in scaling up ASC-based tissue engineering to a clinically-useful volume. Secondly, the differentiation of ASC into cell lineages apart from adipocytes has not been conclusively demonstrated in many studies, due to the use of rather simplistic approaches to the confirmation of differentiation, such as the use of non-specific histological dyes, or a small number of molecular markers of uncertain significance. Thirdly, the ASC prepared from human lipoaspirate for different studies differ in purity and molecular phenotype, with many studies using cell preparations that are likely to contain heterogeneous populations of cells, making it uncertain whether ASC themselves are responsible for effects observed. Hence while one clinical application already looks convincing, the full clinical potential of ASC awaits much deeper investigation of their fundamental biology. PMID: 21218444 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Optimization of electrical stimulation parameters for cardiac tissue engineering. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Tandon N, Marsano A, Maidhof R, Wan L, Park H, Vunjak-Novakovic G In vitro application of pulsatile electrical stimulation to neonatal rat cardiomyocytes cultured on polymer scaffolds has been shown to improve the functional assembly of cells into contractile engineered cardiac tissues. However, to date, the conditions of electrical stimulation have not been optimized. We have systematically varied the electrode material, amplitude and frequency of stimulation to determine the conditions that are optimal for cardiac tissue engineering. Carbon electrodes, exhibiting the highest charge-injection capacity and producing cardiac tissues with the best structural and contractile properties, were thus used in tissue engineering studies. Engineered cardiac tissues stimulated at 3 V/cm amplitude and 3 Hz frequency had the highest tissue density, the highest concentrations of cardiac troponin-I and connexin-43 and the best-developed contractile behaviour. These findings contribute to defining bioreactor design specifications and electrical stimulation regime for cardiac tissue engineering. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21218514 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Type I collagen, fibrin and PuraMatrix matrices provide permissive environments for human endothelial and mesenchymal progenitor cells to form neovascular networks. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Allen P, Melero-Martin J, Bischoff J The field of tissue engineering seeks to create metabolically demanding, functional tissues, which will require blood vessel networks capable of forming rapidly in a variety of extracellular matrix (ECM) environments. We tested whether human endothelial progenitor cells (EPCs) and mesenchymal progenitor cells (MPCs) could form microvascular networks in type I collagen, fibrin and an engineered peptide hydrogel, PuraMatrix, in 7 days in vivo in immune-deficient mice. These results are compared to those previously published, based on the Matrigel ECM. Perfused blood vessels formed in all three types of ECM within 7 days. Collagen at 5 and 6 mg/ml and 10 mg/ml fibrin supported vessel formation at 30-60 vessels/mm(2), and PuraMatrix enabled vessel formation to 160 vessels/mm(2), significantly greater than collagen or fibrin. Vessels were composed of EPCs with perivascular cells on their abluminal surfaces. EPCs injected alone formed a low density of blood vessels in collagen and PuraMatrix, while MPCs injected alone resulted in sparse vessel networks in all ECMs tested. A rheometer was used to determine whether the ECMs which supported vascularization had bulk physical properties similar to or distinct from Matrigel. Collagen and fibrin were the stiffest matrices to support extensive vascularization, with storage moduli in the range 385-510 Pa, while Matrigel, at 80 Pa, and PuraMatrix, at 5 Pa, were far more compliant. Thus, EPCs and MPCs were capable of vasculogenesis in environments having disparate physical properties, although vascular density was greater in more compliant ECMs. We propose that EPC/MPC-mediated vascularization is a versatile technology which may enable the development of engineered organs. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21218469 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Distinct phenotypes and regenerative potentials of early endothelial progenitor cells and outgrowth endothelial progenitor cells derived from umbilical cord blood. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Reagan J, Foo T, Tracy Watson J, Jin W, Moed BR, Zhang Z The capability of postnatal neovascularization makes circulating endothelial progenitor cells (EPCs) promising for regenerative medicine and tissue engineering. Using EPCs isolated from umbilical cord blood, this study aimed to clarify the transition of functional properties from early EPCs (e-EPCs) to outgrowth EPCs (og-EPCs) for potential applications in regenerative medicine. Mononuclear cells were collected from umbilical cord blood via density gradient centrifugation and further negatively selected by CD45. EPCs were sorted from mononuclear cells by the expression of CD34. e-EPCs (7 days of culture) and og-EPCs (3 weeks of culture) were characterized by morphology, intake of acetylated low-density lipoprotein, vessel-cord formation, cell surface phenotype and the expression of angiogenic genes. e-EPCs and og-EPCs were also compared for osteogenic differentiation under the stimulation of BMP-2. Chemotaxis by SDF-1 was compared among og-EPCs and the first- and second-day attached e-EPCs. Based on the expression of angiogenic genes, e-EPCs possessed few angiogenic properties in vitro and og-EPCs were angiogenic. e-EPCs, however, expressed significant CXCR4 and migrated toward the SDF-1 gradient. og-ECPs did not express CXCR4 and showed no response to SDF-1. During culture, gaining an angiogenic phenotype by og-EPCs is associated with the loss of homing potential. These contrast properties determine different potentials of e-EPCs and og-EPCs in regenerative medicine. Copyright © 2010 John Wiley & Sons, Ltd. PMID: 21218468 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | State of the art and future perspectives of articular cartilage regeneration: a focus on adipose-derived stem cells and platelet-derived products. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Hildner F, Albrecht C, Gabriel C, Redl H, van Griensven M Trauma, malposition and age-related degeneration of articular cartilage often result in severe lesions that do not heal spontaneously. Many efforts over the last centuries have been undertaken to support cartilage healing, with approaches ranging from symptomatic treatment to structural cartilage regeneration. Microfracture and matrix-associated autologous chondrocyte transplantation (MACT) can be regarded as one of the most effective techniques available today to treat traumatic cartilage defects. Research is focused on the development of new biomaterials, which are intended to provide optimized physical and biochemical conditions for cell proliferation and cartilage synthesis. New attempts have also been undertaken to replace chondrocytes with cells that are more easily available and cause less donor site morbidity, e.g. adipose derived stem cells (ASC). The number of in vitro studies on adult stem cells has rapidly increased during the last decade, indicating that many variables have yet to be optimized to direct stem cells towards the desired lineage. The present review gives an overview of the difficulties of cartilage repair and current cartilage repair techniques. Moreover, it reviews new fields of cartilage tissue engineering, including stem cells, co-cultures and platelet-rich plasma (PRP). Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21218467 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Retroviral expression of MIR2 decreases both surface MHC class I and the alloimmune CTL response. J Tissue Eng Regen Med. 2011 Jan 10; Authors: Thakur A, Hummel J, Sengupta R, Gupta V, Mossman K, Jones K The immune response to allogeneic cells in tissue-engineered constructs is a major barrier to their successful application in the treatment of many human diseases. Specifically, the T cell-mediated immune response, initiated through the recognition of cell surface MHCI molecules, is the primary cause of acute cellular allograft rejection. In this study, we altered expression of MHCI through viral immunomodulatory mechanisms to examine whether allogeneic cells could be made to 'mimic' viral evasion of a host CTL response. We demonstrate the successful application of a retroviral vector in vitro to overexpress the Kaposi's sarcoma-associated herpesvirus immunomodulatory protein, MIR2, in human monocyte-like myeloid progenitor cells. This approach led to differential downregulation of cell surface MHCI, ICAM-1 and B7-2 molecules. We also demonstrate that downregulation of immunoactive molecules has the functional effect of significantly reducing T cell-mediated cytotoxicity without altering NK-mediated cytotoxicity in vitro. These results provide proof-of-concept that viral immune evasion strategies allow cell-based tissue-engineered constructs to delay or even prevent acute cellular immune rejection in vivo. Importantly, this methodology could facilitate the development of universal donor cells for tissue engineering applications. Copyright © 2011 John Wiley & Sons, Ltd. PMID: 21218465 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Concise Review: Human Adipose-Derived Stem Cells (ASC): Separating Promise from Clinical Need. Stem Cells. 2011 Jan 7; Authors: Locke M, Feisst V, Dunbar PR Human ASC have become of increasing interest to both stem cell biologists and clinicians because of their potential to differentiate into adipogenic, osteogenic, chondrogenic and other mesenchymal lineages, as well as other clinically useful properties attributed to them, such as stimulation of angiogenesis and suppression of inflammation. ASC have already been used in a number of clinical trials, and some successful outcomes have been reported, especially in tissue reconstruction. However a critical review of the literature reveals considerable uncertainty about the true clinical potential of human ASC. Firstly, the surgical needs that ASC might answer remain relatively few, given the current difficulties in scaling up ASC-based tissue engineering to a clinically-useful volume. Secondly, the differentiation of ASC into cell lineages apart from adipocytes has not been conclusively demonstrated in many studies, due to the use of rather simplistic approaches to the confirmation of differentiation, such as the use of non-specific histological dyes, or a small number of molecular markers of uncertain significance. Thirdly, the ASC prepared from human lipoaspirate for different studies differ in purity and molecular phenotype, with many studies using cell preparations that are likely to contain heterogeneous populations of cells, making it uncertain whether ASC themselves are responsible for effects observed. Hence while one clinical application already looks convincing, the full clinical potential of ASC awaits much deeper investigation of their fundamental biology. PMID: 21218444 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation of 3D Fibroin/Chitosan Blend Porous Scaffold for Tissue Engineering Via a Simplified Method. Macromol Biosci. 2011 Jan 7; Authors: Ruan Y, Lin H, Yao J, Chen Z, Shao Z In this work, we developed a simple and flexible method to manufacture a 3D porous scaffold based on the blend of regenerated silk fibroin (RSF) and chitosan (CS). No crosslinker or other toxic reagents were used in this method. The pores of resulted 3D scaffolds were connected with each other, and their sizes could be easily controlled by the concentration of the mixed solution. Compared with pure RSF scaffolds, the water absorptivities of these RSF/CS blend scaffolds with significantly enhanced mechanical properties were greatly increased. The results of MTT and RT-PCR tests indicated that the chondrocytes grew very well in these blend RSF/CS porous scaffolds. This suggested that the RSF/CS blend scaffold prepared by this new method could be a promising candidate for applications in tissue engineering. PMID: 21218404 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A molecular dynamic analysis of gelatin as an amorphous material: Prediction of mechanical properties of gelatin systems. Int J Artif Organs. 2010 Nov 23; Authors: Zaupa A, Neffe AT, Pierce BF, Lendlein A, Hofmann D Biomaterials are used in regenerative medicine for induced autoregeneration and tissue engineering. This is often challenging, however, due to difficulties in tailoring and controlling the respective material properties. Since functionalization is expected to offer better control, in this study gelatin chains were modified with physically interacting groups based on tyrosine with the aim of causing the formation of physical crosslinks. This method permits application-specific properties like swelling and better tailoring of mechanical properties. The design of the crosslink strategy was supported by molecular dynamic (MD) simulations of amorphous bulk models for gelatin and functionalized gelatins at different water contents (0.8 and 25 wt.-%). The results permitted predictions to be formulated about the expected crosslink density and its influence on equilibrium swelling behavior and on elastic material properties. The models of pure gelatin were used to validate the strategy by comparison between simulated and experimental data such as density, backbone conformation angle distribution, and X-ray scattering spectra. A key result of the simulations was the prediction that increasing the number of aromatic functions attached to the gelatin chain leads to an increase in the number of physical netpoints observed in the simulated bulk packing models. By comparison with the Flory-Rehner model, this suggested reduced equilibrium swelling of the functionalized materials in water, a prediction that was subsequently confirmed by our experimental work. The reduction and control of the equilibrium degree of swelling in water is a key criterion for the applicability of functionalized gelatins when used, for example, as matrices for induced autoregeneration of tissues. PMID: 21218393 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Angiogenesis in Wounds Treated by Microdeformational Wound Therapy. Ann Surg. 2011 Jan 6; Authors: Erba P, Ogawa R, Ackermann M, Adini A, Miele LF, Dastouri P, Helm D, Mentzer SJ, D'Amato RJ, Murphy GF, Konerding MA, Orgill DP BACKGROUND:: Mechanical forces play an important role in tissue neovascularization and are a constituent part of modern wound therapies. The mechanisms by which vacuum assisted closure (VAC) modulates wound angiogenesis are still largely unknown. OBJECTIVE:: To investigate how VAC treatment affects wound hypoxia and related profiles of angiogenic factors as well as to identify the anatomical characteristics of the resultant, newly formed vessels. METHODS:: Wound neovascularization was evaluated by morphometric analysis of CD31-stained wound cross-sections as well as by corrosion casting analysis. Wound hypoxia and mRNA expression of HIF-1α and associated angiogenic factors were evaluated by pimonidazole hydrochloride staining and quantitative reverse transcription-polymerase chain reaction (RT-PCR), respectively. Vascular endothelial growth factor (VEGF) protein levels were determined by western blot analysis. RESULTS:: VAC-treated wounds were characterized by the formation of elongated vessels aligned in parallel and consistent with physiologically function, compared to occlusive dressing control wounds that showed formation of tortuous, disoriented vessels. Moreover, VAC-treated wounds displayed a well-oxygenated wound bed, with hypoxia limited to the direct proximity of the VAC-foam interface, where higher VEGF levels were found. By contrast, occlusive dressing control wounds showed generalized hypoxia, with associated accumulation of HIF-1α and related angiogenic factors. CONCLUSIONS:: The combination of established gradients of hypoxia and VEGF expression along with mechanical forces exerted by VAC therapy was associated with the formation of more physiological blood vessels compared to occlusive dressing control wounds. These morphological changes are likely a necessary condition for better wound healing. PMID: 21217515 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Alpha Gal 1, 3-transferase Knock out does not Alter the Properties of Porcine Extracellular Matrix Bioscaffolds. Acta Biomater. 2011 Jan 6; Authors: Liang R, Fisher M, Yang G, Hall C, Woo SL Extracellular matrix (ECM) bioscaffolds, such as porcine small intestine submucosa (SIS) and urinary bladder matrix (UBM), have been used successfully to improve soft tissue healing. Yet, they contain plenty of galactose-α1, 3-galactose (αGal) epitopes which cause rejection responses in pig organ transplantation to human. Recently, ECM bioscaffolds derived from genetically modified pigs that are αGal deficient (αGal(-)) have become available. To ensure that the ECM bioscaffolds from these pigs can be used as alternatives, we examined their morphological, bioactive and biomechanical properties and compared them with those from the wild type pigs (n=5 per group). Morphologically, the αGal(-) ECMs were found to be similar to the wild type ECMs in gross observation and matrix appearance with H&E staining. Growth factors commonly known to be present in ECM bioscaffolds including FGF-2, TGF-β1, VEGF, IGF-1 and PDGF-BB also showed no significant differences in terms of quantity (p>0.05) and distribution in tissue from the results of ELISA, western blot and immunohistochemistry. Furthermore, BrdU cell proliferation assay confirmed the bioactivity of the extracts from the αGal(-) bioscaffolds to be similar as the wild type bioscaffolds. Under uniaxial tensile testing, no significant differences were found between the αGal(-) and wild type bioscaffolds in terms of their viscoelastic and mechanical properties (p>0.05). These multidisciplinary results suggest that genetic modification to eliminate the αGal epitopes in the ECM bioscaffolds had not altered the properties of these ECM bioscaffolds and as such, they should retain their performance in tissue engineering in humans. PMID: 21216306 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | MATRIGEL IMPROVES FUNCTIONAL PROPERTIES OF HUMAN SUBMANDIBULAR SALIVARY GLAND CELL LINE. Int J Biochem Cell Biol. 2011 Jan 6; Authors: Maria OM, Maria S, Liu Y, Komarova SV, Tran SD Sjogren's syndrome and radiotherapy for head and neck cancers result in irreversible damage to functional salivary tissue, for which no adequate treatment is available. The microenvironment for salivary gland cell cytodifferentiation is critical for the future development of salivary gland regeneration, repair and tissue engineering treatments. Results from this study indicate that human submandibular cell line (HSG) cultured on Matrigel (2mg/ml) could be induced to differentiate into polarized secretory acinar-like cells. The HSG cells grown on Matrigel were evaluated by physiological functional assays, molecular and immunohistochemistry, immunofluorescence, and morphological assessments. The results showed (1) a decrease in cell proliferation; (2) an increase in cell apoptosis; (3) cellular polarization evident by transepithelial electrical resistance (TER), expressions of tight junction proteins (claudin-1,2,3,4, occludin, JAM-A, and ZO-1) and transmission electron microscopy (TEM); (4) an increase in the production and/or secretion of acinar cell proteins, i.e., alpha-amylase, aquaporin-5, cytokeratins, and mucin-1, that were not associated with increases in mRNA transcription; (5) a decrease in vimentin expression; and (6) expression of potential stem cell biomarkers CD44 and CD166. The data indicated that Matrigel provided a suitable microenvironment for morphological and functional differentiation of HSG cells into 3-D acinar like cells. This study provides an in vitro model and baseline data on future developments of new strategies for salivary gland regeneration and replacement. PMID: 21216302 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Photopolymerized Water-soluble Chitosan-based Hydrogel as Potential Use in Tissue Engineering. Int J Biol Macromol. 2011 Jan 5; Authors: Zhou Y, Ma G, Shi S, Yang D, Nie J Novel biodegradable hdrogels by photocrosslinking macromers based on chitosan derivative are reported. Photocrosslinkable macromers, a water-soluble (methacryloyloxy) ethyl carboxyethyl chitosan were prepared by Michael-addition reaction between chitosan and ethylene glycol acrylate methacrylate. The macromers were characterized by Fourier transform infrared spectroscopy, (1)H NMR and (13)C NMR. Hydrogels were fabricated by exposing aqueous solutions of macromers with 0.1% (w/v) photoinitiator to UV light irradiation, and their swelling kinetics as well as degradation behaviours was evaluated. The results demonstrated that the degradation rates were affected strongly by crosslinking density. The hydrogel was compatible to Vero cells, not exhibiting significant cytotoxicity. Cell culture assay also demonstrated that the hydrogels were good in promoting the cell attachment and proliferation, showing their potential as tissue engineering scaffolds. PMID: 21215773 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Perfusion Electrodeposition of Calcium Phosphate on Additive Manufactured Titanium Scaffolds for Bone Engineering. Acta Biomater. 2011 Jan 4; Authors: Chai YC, Truscello S, Van Bael S, Luyten FP, Vleugels J, Schrooten J A perfusion electrodeposition (P-ELD) system was reported to functionalise additive manufactured Ti6Al4V scaffolds with a calcium phosphate (CaP) coating in a controlled and reproducible manner. The effects and interactions of four main process parameters: current density (I), deposition time (t), flow rate (f) and process temperature (T) on the properties of the CaP coating were investigated. The results showed a direct relation between the parameters and the deposited CaP mass, with a significant effect for t (p = 0.001) and t-f interaction (p = 0.019). Computational fluid dynamic (CFD) analysis showed a relatively low electrolyte velocity within the struts and a high velocity in the open areas within the P-ELD chamber, which were not influenced by a change in f. This is beneficial for promoting a controlled CaP deposition and hydrogen gas removal. Optimisation studies showed a minimum t of 6 hours was needed to obtain complete coating of the scaffold regardless of I used and the thickness increased by increasing I and t. Energy dispersive X-ray (EDAX) and X-ray diffraction (XRD) analysis confirmed the deposition of highly crystalline synthetic carbonated hydroxyapatite under all conditions (Ca/P ratio = 1.41). High cell viability and cell-material interactions were demonstrated by in vitro culture of human periosteum derived cells (hPDCs) on coated scaffolds. This study showed that P-ELD provides a technological tool to functionalise complex scaffold structures with a biocompatible CaP layer that has controlled and reproducible physicochemical properties suitable for bone engineering. PMID: 21215337 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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