|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Single-walled carbon nanotubes alter Schwann cell behavior differentially within 2D and 3D environments. J Biomed Mater Res A. 2010 Oct 14; Authors: Behan BL, Dewitt DG, Bogdanowicz DR, Koppes AN, Bale SS, Thompson DM Both spinal cord injury (SCI) and large-gap peripheral nerve defects can be debilitating affecting a patient's long-term quality of life and presently, there is no suitable treatment for functional regeneration of these injured tissues. A number of works have suggested the benefits of electrical stimulation to promote both glial migration and neuronal extension. In this work, an electrically conductive hydrogel containing single-walled carbon nanotubes (SWCNT) for neural engineering applications is presented and the Schwann cell (SC) response to SWCNT is examined in both 2D and 3D microenvironments. Results from clonogenic and alamarBlue(®) assays in 2D indicate that SWCNT (10-50 μg mL(-1)) inhibit SC proliferation but do not affect cell viability. Following SWCNT exposure in 2D, changes in SC morphology can be observed with the nanomaterial attached to the cell membrane at concentrations as low as 10 μg mL(-1). In contrast to the results gathered in 2D, SC embedded within the 3D hydrogel loaded with 10-50 μg mL(-1) of SWCNT exhibited little or no measurable change in cell proliferation, viability, or morphology as assessed using a digestion assay, alamarBlue, and confocal microscopy. Collectively, this highlights that an electrically-conductive SWCNT collagen I-Matrigel™ biomaterial may be suitable for neural tissue engineering and is able to sustain populations of SC. Findings suggest that 2D nanoparticle toxicity assays may not be accurate predictors of the 3D response, further motivating the examination of these materials in a more physiologically relevant environment. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2010. PMID: 20949573 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Paramagnetic nanofibrous composite films enhance the osteogenic responses of pre-osteoblast cells. Nanoscale. 2010 Oct 15; Authors: Meng J, Zhang Y, Qi X, Kong H, Wang C, Xu Z, Xie S, Gu N, Xu H In this work, a paramagnetic nanofibrous composite film was fabricated with poly lactide, hydroxyapatite and γ-Fe(2)0(3) nanoparticles using the electrospinning technique. The composite film significantly enhanced the proliferation, differentiation and ECM secretion of the osteoblast cells under a static magnetic field, which offers promising application potentials in bone tissue engineering and bone regeneration therapy. PMID: 20949222 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chitosan composites for bone tissue engineering-an overview. Mar Drugs. 2010;8(8):2252-66 Authors: Venkatesan J, Kim SK Bone contains considerable amounts of minerals and proteins. Hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2)] is one of the most stable forms of calcium phosphate and it occurs in bones as major component (60 to 65%), along with other materials including collagen, chondroitin sulfate, keratin sulfate and lipids. In recent years, significant progress has been made in organ transplantation, surgical reconstruction and the use of artificial protheses to treat the loss or failure of an organ or bone tissue. Chitosan has played a major role in bone tissue engineering over the last two decades, being a natural polymer obtained from chitin, which forms a major component of crustacean exoskeleton. In recent years, considerable attention has been given to chitosan composite materials and their applications in the field of bone tissue engineering due to its minimal foreign body reactions, an intrinsic antibacterial nature, biocompatibility, biodegradability, and the ability to be molded into various geometries and forms such as porous structures, suitable for cell ingrowth and osteoconduction. The composite of chitosan including hydroxyapatite is very popular because of the biodegradability and biocompatibility in nature. Recently, grafted chitosan natural polymer with carbon nanotubes has been incorporated to increase the mechanical strength of these composites. Chitosan composites are thus emerging as potential materials for artificial bone and bone regeneration in tissue engineering. Herein, the preparation, mechanical properties, chemical interactions and in vitro activity of chitosan composites for bone tissue engineering will be discussed. PMID: 20948907 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional in vitro follicle growth: overview of culture models, biomaterials, design parameters and future directions. Reprod Biol Endocrinol. 2010 Oct 14;8(1):119 Authors: Desai N, Alex A, Abdelhafez F, Calabro A, Goldfarb J, Fleischman A, Falcone T ABSTRACT: In vitro ovarian follicle culture is a new frontier in assisted reproductive technology with tremendous potential, especially for fertility preservation. Folliculogenesis within the ovary is a complex process requiring interaction between somatic cell components and the oocyte. Conventional two-dimensional culture on tissue culture substrata impedes spherical growth and preservation of the spatial arrangements between oocyte and surrounding granulosa cells. Granulosa cell attachment and migration can leave the oocyte naked and unable to complete the maturation process. Recognition of the importance of spatial arrangements between cells has spurred research in to three-dimensional culture system. Such systems may be vital when dealing with human primordial follicles that may require as long as three months in culture. In the present work we review pertinent aspects of in vitro follicle maturation, with an emphasis on tissue-engineering solutions for maintaining the follicular unit during the culture interval. We focus primarily on presenting the various 3-dimensional culture systems that have been applied for in vitro maturation of follicle:oocyte complexes. We also try to present an overview of outcomes with various biomaterials and animal models and also the limitations of the existing systems. PMID: 20946661 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Possibility of Skin Epithelial Cell Transdifferentiation in Tracheal Reconstruction. Artif Organs. 2010 Oct 14; Authors: Kim JH, Kong WH, Kim JG, Kim HJ, Seo SW In tissue engineering, injured tissue is normally reconstructed with cells obtained from that tissue itself. However, it is difficult to obtain cells for reconstruction of the trachea because of its shape and limited accessibility. Therefore, other cell sources having similar form and function or stem cells are used for tracheal reconstruction. In a previous study, we used autologous skin epithelial cells and successfully reconstructed canine tracheas. We found that the tracheal epithelial layer was completely covered with ciliated cells, which is a remarkable finding because skin and tracheal epithelial cells originate from different germinal layers and have very different forms. In this study, to elucidate the origin of the ciliated cells, we identified the stem cell contents of skin epithelial cells on primary culture, marked the skin epithelial cells with PKH26 dye, and transplanted them onto canine tracheas. After 5 months, we identified PKH26 fluorescence on the tracheal epithelial layers, especially over the tracheal cartilages. Consequently, we demonstrated that transplanted autologous skin epithelial stem cells can remain viable on the trachea for a few months and can transdifferentiate into tracheal epithelial cells and chondrocytes. PMID: 20946312 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Explant Culture: An Efficient Method to Isolate Adipose-Derived Stromal Cells for Tissue Engineering. Artif Organs. 2010 Oct 14; Authors: Jing W, Xiao J, Xiong Z, Yang X, Huang Y, Zhou M, Chen S, Lin Y, Tian W Enzymatic digestion, the commonly used method of adipose-derived stromal cells isolation, is time consuming and expensive, especially when applied to large volumes of tissue. In the present study, the characteristics of the cells obtained by adipose tissue explant culture were studied. We found that adipose tissue fragments could adhere onto the growth surface of flasks in a very short time after plating and that fibroblast-like cells migrated from the explants and reached confluence. Morphologic analysis and surface markers expression suggested the mesenchymal origin of the cells derived from adipose tissue explants. After in vitro expansion these cells were successfully induced into adipogenic, osteogenic, and chondrogenic lineages, which demonstrated their multipotency. The high growth rate and colony-forming efficiency of explant-derived cells were similar to those of cells obtained by digestion. Furthermore, explant culture gave higher yield of cells than digestion method after primary culture. The experiment of ectopic adipogenesis in nude mice suggested the prospects for tissue engineering of these cells. In conclusion, we obtained multipotent stromal cells from adipose tissue by explant culture, and this method was simple, time saving, and gave a high yield of cells. Therefore, explant culture can be used as an effective way to isolate adipose-derived stromal cells for tissue engineering. PMID: 20946305 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Molecular weight fibrinogen variants alter gene expression and functional characteristics of human endothelial cells. J Thromb Haemost. 2010 Oct 5; Authors: Weijers EM, Van Wijhe MH, Joosten L, Horrevoets AJ, De Maat MP, Van Hinsbergh VW, Koolwijk P Background: Fibrin is a temporary matrix, which not only seals a wound, but also provides a temporary matrix structure for invading cells during wound healing. Two naturally occurring fibrinogen variants, high molecular weight (HMW) and low molecular weight (LMW) fibrinogen, display different properties in supporting angiogenesis in vivo and in vitro. Objectives: This study aims to investigate the functional characteristics and molecular mechanisms of human microvascular endothelial cells (HMVEC) cultured on HMW- and LMW-fibrin matrices. Methods and Results: HMVEC on HMW-fibrin matrices showed increased proliferation and tube formation as compared to their counterparts on unfractionated- and LMW-fibrin. Degradation of HMW-fibrin was markedly enhanced by the presence of HMVEC, that of LMW-fibrin only slightly. However, the expression of fibrinolysis regulating proteins and integrins were similar. Subsequent micro-array analysis revealed that the expression of 377 genes differed significantly between HMVEC cultured on HMW- and LMW-fibrin. Among these genes UNC5B, DLL4 and DLL4-Notch downstream targets Hey1, Hey2 and Hes1 were increased in HMVEC on LMW-fibrin. However, pharmacological and genetic (DLL4 siRNA) inhibition DLL4-Notch signaling blunted rather than enhanced proliferation and tube formation by HMVEC on both fibrin variants. Conclusions: Heterogeneity in natural occurring fibrinogen strongly influences endothelial cell proliferation and tube formation and causes alterations in gene expressions, including that of DLL4-Notch. The higher fibrinolytic sensitivity of HMW-fibrin in the presence of HMVEC contributes to increased tube formation. While DLL4-Notch was altered, it did not explain the enhanced tube formation in HMW-fibrin. This study provides new perspectives for biological and tissue engineering applications. PMID: 20946180 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Myogenic differentiation of mesenchymal stem cells co-cultured with primary myoblasts. Cell Biol Int. 2010 Oct 15; Authors: Beier JP, Bitto FF, Lange C, Klumpp D, Arkudas A, Bleiziffer O, Boos A, Horch RE, Kneser U Background Tissue Engineering of skeletal muscle is a promising method to reconstruct loss of muscle tissue. The aim of this study was to evaluate mesenchymal stem cells as new cell source for this application. Results As a new approach to differentiate the mesenchymal stem cells (MSC) towards the myogenic lineage, co-cultivation with primary myoblasts was developed in this study and myogenic potential of green fluorescenting protein (GFP)-transduced rat MSC co-cultured with primary rat myoblasts was assessed. Myogenic potential of MSC was analysed by immunocytochemistry, fluorescence activated cell sorting and quantitative polymerase chain reaction. MSC - myoblast fusion phenomena leading to hybrid myotubes were evaluated using a novel method to evaluate myotube fusion ratios based on phase contrast and fluorescence microscopy. Furthermore, MSC constitutively expressed the myogenic markers myogenic enhancer factor 2 (MEF2) and a-sarcomeric actin and MEF2 expression was upregulated upon co-cultivation with primary myoblasts and the addition of myogenic medium supplements. Significantly higher numbers of MSC nuclei were involved in myotube formations when basic fibroblast growth factor (bFGF) and dexamethasone were added to co-cultures. Conclusion In summary we developed and determined optimal co-culture conditions for MSC myogenic differentiation up to myotube formations as a promising step towards applicability of MSC as a cell source for skeletal muscle Tissue Engineering as well as other muscle-cell based therapies. PMID: 20946104 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Integrative emphases on intimate, intrinsic propensity/pathological processes--causes of self recovery limits and also, subtle related targets for neuroprotectionl pleiotropicity/multimodal actions, by accessible therapeutic approaches--in spinal cord injuries. J Med Life. 2010 Jul-Sep;3(3):262-74 Authors: Onose G, Haras M, Anghelescu A, Mureşanu D, Giuglea C, Daia Chendreanu C BACKGROUND: The last two decades have come up with some important progresses in the genetic, immune, histochemical and bio (nano)-technological domains, that have provided new insight into cellular/molecular mechanisms, occurring in the central nervous system (CNS)--including in spinal cord-injuries. METHODS: In previous works, emerging from our theoretical and practical endeavors in the field, we have thoroughly described the principal intimate propensity and the pathophysiological processes--representing intrinsic limitations for self-recovery after SCI, and, at the same time, subtle targets for neuroprotection/recovery--and reviewed the main related worldwide-published reports. The aim of this paper is to emphasize the connections between such main aspects and some feasible integrative solutions, including the ones for clinical practice. RESULTS: Consequently, we stress upon some therapeutic suggestions regarding this subject matter by systematizing the most up to date and efficient ones--obviously, within major limits, according to the very low capacities of CNS/ spinal cord (SC) to post-injury self preserve and recover. Moreover, we also talk about accessible drugs, respectively those being already in clinical use (but at present, mainly used to treat other conditions, including the neurological ones) and hence, with relatively well known, determined effects and/or respectively, restrictions. DISCUSSIONS: The recent advances in the knowledge on the basic components of the afore mentioned CNS/ SC propensity for self destroying and inefficient endogenous repair mechanisms in the actual new context, will hopefully be, from now on, more effectively correlated with revolutionary--mostly still experimental--treatments, especially by using stem cells within tissue engineering, including, if needed, more advanced/courageous approaches, based on somatic cell nuclear transfer (SCNT). CONCLUSIONS: This paper contains the scientific motivated highlighting of some already available drugs, "neuroprotective" (and not only) properties too, which enable practitioners with (although not yet capable to cure--but anyway) more efficient therapeutic means, to approach the extremely difficult and still painfully disappointing domain, of spinal cord injury (SCI). PMID: 20945817 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Rapid repair and regeneration of damaged rabbit sciatic nerves by tissue-engineered scaffold made from nano-silver and collagen type I. Injury. 2010 May;41(5):522-7 Authors: Ding T, Luo ZJ, Zheng Y, Hu XY, Ye ZX A tissue-engineered scaffold with nano-silver and collagen type I was constructed and investigated for its ability to adsorb laminin and the usefulness in the repair and regeneration of damaged peripheral nerves in animals. The nano-silver scaffold displayed ideal microtubule structure under electronic microscope; even distribution of the nano-silver particles was also seen with energy spectrometry. After immersion in a laminin solution, the laminin-attached scaffolds were implanted into rabbits to repair a 10-mm injury of the sciatic nerve. At 30 days post-implantation, regeneration of the damaged nerve was evaluated by transmission electron microscopy, electrophysiological examination and fluoro-gold (FG) retrograde labelling. Compared with the control collagen-scaffold without nano-silver, the nano-silver-containing scaffold showed a higher rate of laminin adsorption, regenerated a nerve with a thicker myelin sheath and improved the nerve conduction velocity and nerve potential amplitude. FG retrograde labelled the newly grown axons in the spinal cord cortex anterior horn and the dorsal root ganglion. These results demonstrate the superior functionality of the nano-silver-collagen scaffold in the adsorption to laminin and subsequent regeneration of damaged peripheral nerves. PMID: 19524233 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Neutrophil differentiation from human-induced pluripotent stem cells. J Cell Physiol. 2010 Oct 13; Authors: Morishima T, Watanabe KI, Niwa A, Fujino H, Matsubara H, Adachi S, Suemori H, Nakahata T, Heike T Induced pluripotent stem (iPS) cells are of potential value not only for regenerative medicine, but also for disease investigation. The present study describes the development of a neutrophil differentiation system from human iPS cells (hiPSCs) and the analysis of neutrophil function and differentiation. The culture system used consisted of the transfer of hiPSCs onto OP9 cells and their culture with vascular endothelial growth factor (VEGF). After 10 days, TRA 1-85(+)CD34(+)VEGF receptor-2 (VEGFR-2)(high) cells were sorted and co-cultured with OP9 cells in the presence of hematopoietic cytokines for 30 days. Floating cells were collected and subjected to morphological and functional analysis. These hiPSC-derived neutrophils were similar to peripheral blood mature neutrophils in morphology, contained functional neutrophil specific granules, and were equipped with the basic functions such as phagocytosis, superoxide production, and chemotaxis. In the process of differentiation, myeloid cells appeared sequentially from immature myeloblasts to mature segmented neutrophils. Expression patterns of surface antigen, transcription factors and granule proteins during differentiation were also similar to those of granulopoiesis in normal bone marrow. In conclusion, differentiation of mature neutrophils from hiPSCs was successfully induced in a similar process to normal granulopoiesis using an OP9 co-culture system. This system may be applied to elucidate the pathogenesis of various hematological diseases that affect neutrophils. J. Cell. Physiol. © 2010 Wiley-Liss, Inc. PMID: 20945397 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mechanistic insights into reprogramming to induced pluripotency. J Cell Physiol. 2010 Oct 13; Authors: Ho R, Chronis C, Plath K Induced pluripotent stem (iPS) cells can be generated from various embryonic or adult cell types upon expression of a set of few transcription factors, most commonly consisting of Oct4, Sox2, c-Myc and Klf4, following a strategy originally published by Takahashi and Yamanaka in 2006 (Takahashi and Yamanaka, 2006). Since iPS cells are molecularly and functionally similar to embryonic stem (ES) cells, they provide a source of patient-specific pluripotent cells for regenerative medicine and disease modeling, and therefore have generated enormous scientific and public interest. The generation of iPS cells also presents a powerful tool for dissecting mechanisms that stabilize the differentiated state and are required for the establishment of pluripotency. In this review, we discuss our current view of the molecular mechanisms underlying transcription factor-mediated reprogramming to induced pluripotency. © 2010 Wiley-Liss, Inc. PMID: 20945378 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human embryonic stem cell proliferation and differentiation as parameters to evaluate developmental toxicity. J Cell Physiol. 2010 Oct 13; Authors: Pal R, M MK, Das AK, Bhonde R In vitro models based on embryonic stem cells (ESC) are highly promising for improvement of predictive toxicology screening in humans. After the successful validation of Embryonic Stem Cell Test (EST) in 2001; concerns have been raised on the usage of mouse ESC and also the morphological evaluation of beating cell clusters. This requires specialized skill-sets and is highly prone to misjudgement and false positive results. To overcome these limitations, we undertook the present study incorporating improvisations over the conventional EST. Here, we explored the potential of a human ESC (hESC)- based assay to evaluate the potential toxicity of Penicillin-G, Caffeine and Hydroxyurea. Drug treatment inhibited hESC adhesion and substantially altered the morphology and viability (˜50%) of embryoid bodies (EBs). Flow cytometry analysis not only showed a significant increase of apoptotic cells in the highest doses but also induced a diverse pattern in DNA content and cell cycle distribution relative to control. Both semi-quantitative and quantitative RT-PCR studies revealed a selective down regulation of markers associated with stemness (NANOG, REX-1, SOX-2, hTERT); cardiac mesoderm (Cripto1, MEF-2C and Brachyury); hepatic endoderm (AFP, HNF-3β, HNF-4α, GATA-4 and SOX-17); and neuroectoderm (NESTIN, SOX-1, NURR1, NEFH, Synaptophysin, TH and Olig2) in a drug as well as dose dependent manner indicating abnormal differentiation. Furthermore, a decrease in the expression of AFP and GFAP proteins followed by a dose-dependent reduction in the levels of hCG-β, Progesterone-II and Estradiol hormones was demonstrated by immunocytochemistry and ECLIA respectively. This new and unique approach comprising of DNA cell cycle analysis, germ layer-specific marker expression and hormone levels as endpoints might offer a clinically relevant and commercially viable alternative for predicting in vivo developmental toxicity. J. Cell. Physiol. © 2010 Wiley-Liss, Inc. PMID: 20945368 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cell surface N-glycans mediated isolation of mouse neural stem cells. J Cell Physiol. 2010 Oct 13; Authors: Hamanoue M, Okano H The isolation of neural stem cells (NSCs) has been hampered by the lack of valid cell surface antigens on NSCs, and novel valuable markers have been proposed. Glycan (oligosaccharide chain) is a potential candidate as a marker to isolate NSCs, because the species and the combination order of saccharides in glycan generate remarkable structural diversity and specificity. At present, the expression of hundreds of glycoconjugates with glycans have been found in the NSCs; however, just a few glycan-epitopes have been identified as valuable cell surface markers. This review focused on the isolation of NSC using glycoprotein, especially complex-type N-glycans. The cell surface N-glycan mediated isolation of NSCs is therefore expected to provide a comprehensive understanding of the biologic characteristics of NSCs in the brain, and thereby help to develop novel strategies in the field of regenerative medicine. © 2010 Wiley-Liss, Inc. PMID: 20945342 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | NRSF Silencing Induces Human Amniotic Fluid-Derived Stem Cell Differentiation into Insulin-Producing Cells. Stem Cells Dev. 2010 Oct 13; Authors: Li B, Wang S, Liu H, Liu D, Zhang J, Zhang B, Yao H, Lv Y, Wang R, Chen L, Yue W, Li Y, Pei XT Islet cell replacement represents the most promising approach for the treatment of type I diabetes. However, it is limited by a shortage of pancreas donors. Here, we report that human amniotic fluid-derived stem cells (hAFSCs) can be induced to differentiate into functional insulin-producing cells by knocking down neuronal restrictive silencing factor (NRSF). In this study, lentiviral vectors were used to deliver small interference NRSF RNA (siNRSF) into hAFSCs. After infection with lentivirus containing siNRSF, hAFSCs were successfully induced to differentiate into insulin-producing cells. The differentiated siNRSF-hAFSCs expressed genes specific for islet cells, such as Pdx1, Hnf4α, Isl-1, Nkx6.1, Insulin, and Glut2. These cells also produced and released C-peptide in a glucose-responsive manner. These findings indicated that hAFSCs could be induced to differentiate into insulin-producing β-like cells by NRSF silencing. PMID: 20942606 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A changing time: the International Society for Cellular Therapy embraces its industry members. Cytotherapy. 2010 Nov;12(7):853-856 Authors: Deans R, Gunter KC, Allsopp T, Bonyhadi M, Burger SR, Carpenter M, Clark T, Cox CS, Driscoll D, Field E, Huss R, Lardenoije RX, Lodie TA, Mason C, Neubiser R, Rasko JE, Rowley J, Maziarz RT Abstract The last decade has seen a dramatic rise in the development of new cellular therapeutics in a wide range of indications. There have been acceptable safety profiles reported in early studies using blood-derived and adherent stem cell products, but also an inconsistent efficacy record. Further expansion has been hindered in part by a lack of capital (both private and public) and delayed entry into the cell therapy space by large healthcare and pharmaceutical companies, those members of the industry most reliably able to initiate and maintain advanced-phase clinical trials. With recognition that the International Society for Cellular Therapy (ISCT) is uniquely positioned to serve the global translational regenerative medicine research community as a network hub for scientific standards and policy, the ISCT commissioned the establishment of an Industry Task Force (ITF) to address current and future roles for industry. The objectives of the ITF were to gather information and prioritize efforts for a new Commercialization Committee (CC) and to construct innovative platforms that would foster constructive and synergistic collaborations between industry and ISCT. Recommendations and conclusions of the ITF included that the new CC: (1) foster new relationships with therapeutic and stem cell societies, (2) foster educational workshops and forums to cross-educate and standardize practices, (3) create industry subcommittees to address priority initiatives, with clear benchmarks and global implementation, and (4) establish a framework for a greater industry community within ISCT, opening doors for industry to share the new vision for commercialization of cell therapy, emphasizing the regenerative medicine space. PMID: 20942603 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Monitoring oxygen uptake in 3D tissue engineering scaffolds by phosphorescence quenching microscopy. Biotechnol Prog. 2010 Sep;26(5):1494-500 Authors: Guaccio A, Netti PA Measuring oxygen concentration in three-dimensional cultures, without interfering with cellular activities, is a fundamental request of tissue engineering research. Among the other techniques, it has been demonstrated that phosphorescence quenching microscopy (PQM) represents a valid tool for the detection of oxygen concentration in 3D environments. Indeed, it is not invasive, with high spatial and temporal resolution, and, once calibrated, it is not affected by the presence of extracellular matrix components and other environmental factors. In this work, a description of the PQM experimental set up for oxygen measurements in solutions and 3D polymer-based cellular constructs is provided. Moreover, the advantage and the limits in the use of this technique are critically discussed to provide a technical note for future applications. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010. PMID: 20945496 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Supermacroprous chitosan-agarose-gelatin cryogels: in vitro characterization and in vivo assessment for cartilage tissue engineering. J R Soc Interface. 2010 Oct 13; Authors: Bhat S, Tripathi A, Kumar A The study focuses on the synthesis of a novel polymeric scaffold having good porosity and mechanical characteristics synthesized by using natural polymers and their optimization for application in cartilage tissue engineering. The scaffolds were synthesized via cryogelation technology using an optimized ratio of the polymer solutions (chitosan, agarose and gelatin) and cross-linker followed by the incubation at sub-zero temperature (-12°C). Microstructure examination of the chitosan-agarose-gelatine (CAG) cryogels was done using scanning electron microscopy (SEM) and fluorescent microscopy. Mechanical analysis, such as the unconfined compression test, demonstrated that cryogels with varying chitosan concentrations, i.e. 0.5-1% have a high compression modulus. In addition, fatigue tests revealed that scaffolds are suitable for bioreactor studies where gels are subjected to continuous cyclic strain. In order to confirm the stability, cryogels were subjected to high frequency (5 Hz) with 30 per cent compression of their original length up to 1 × 10(5) cycles, gels did not show any significant changes in their mass and dimensions during the experiment. These cryogels have exhibited degradation capacity under aseptic conditions. CAG cryogels showed good cell adhesion of primary goat chondrocytes examined by SEM. Cytotoxicity of the material was checked by MTT assay and results confirmed the biocompatibility of the material. In vivo biocompatibility of the scaffolds was checked by the implantation of the scaffolds in laboratory animals. These results suggest the potential of CAG cryogels as a good three-dimensional scaffold for cartilage tissue engineering. PMID: 20943683 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Bioengineering of living renal membranes consisting of hierarchical, bioactive supramolecular meshes and human tubular cells. Biomaterials. 2010 Oct 11; Authors: Dankers PY, Boomker JM, Huizinga-van der Vlag A, Wisse E, Appel WP, Smedts FM, Harmsen MC, Bosman AW, Meijer W, van Luyn MJ Maintenance of polarisation of epithelial cells and preservation of their specialized phenotype are great challenges for bioengineering of epithelial tissues. Mimicking the basement membrane and underlying extracellular matrix (ECM) with respect to its hierarchical fiber-like morphology and display of bioactive signals is prerequisite for optimal epithelial cell function in vitro. We report here on a bottom-up approach based on hydrogen-bonded supramolecular polymers and ECM-peptides to make an electro-spun, bioactive supramolecular mesh which can be applied as synthetic basement membrane. The supramolecular polymers used, self-assembled into nano-meter scale fibers, while at micro-meter scale fibers were formed by electro-spinning. We introduced bioactivity into these nano-fibers by intercalation of different ECM-peptides designed for stable binding. Living kidney membranes were shown to be bioengineered through culture of primary human renal tubular epithelial cells on these bioactive meshes. Even after a long-term culturing period of 19 days, we found that the cells on bioactive membranes formed tight monolayers, while cells on non-active membranes lost their monolayer integrity. Furthermore, the bioactive membranes helped to support and maintain renal epithelial phenotype and function. Thus, incorporation of ECM-peptides into electro-spun meshes via a hierarchical, supramolecular method is a promising approach to engineer bioactive synthetic membranes with an unprecedented structure. This approach may in future be applied to produce living bioactive membranes for a bio-artificial kidney. PMID: 20943265 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue-engineering bone from omentum. Nagoya J Med Sci. 2010 Aug;72(3-4):111-7 Authors: Kamei Y, Toriyama K, Takada T, Yagi S Tissue engineering of bone is an interesting field of research. Many approaches to bone tissue engineering such as from bone marrow stromal cells in vitro have been reported. Furthermore, a model of vascularized tissue-engineered bone flap has been reported. However, there has been no report of bone tissue engineering using omentum. We present a study of tissue engineering of bone from omentum in a rabbit model. The omentum, which was elevated based on the right gastroepiploic vessels, was wrapped by the periosteum from cranial bone in the abdomen of rabbits. We harvested the omentum thus wrapped 1, 2, 4, 6, 8, 12, or 24 weeks after surgery. Within 1 week after surgery, woven bone was formed and clusters of osteoblasts were observed. At 8 weeks, medullization, including the presence of granulocytes, was confirmed. This technique might prove useful for creating tissue-engineered bone flaps for reconstructive surgery. PMID: 20942265 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional early retinal progenitor 3D tissue constructs derived from human embryonic stem cells. J Neurosci Methods. 2010 Jun 30;190(1):63-70 Authors: Nistor G, Seiler MJ, Yan F, Ferguson D, Keirstead HS PURPOSE: To develop three-dimensional (3D) constructs of retinal pigment epithelium (RPE) and early retina progenitor cells from human embryonic stem cells (hESCs). METHODS: 3D tissue constructs were developed by culturing hESC-derived neural retinal progenitors in a matrix on top of hESC-derived RPE cells in a cell culture insert. An osmolarity gradient maintained the nutrition of the 3D cell constructs. Cross-sections through hESC-derived tissue constructs were characterized by immunohistochemistry for various transcription factors and cell markers. RESULTS: hESC-derived tissue constructs expressed transcription factors characteristic of retinal development, such as pax6, Otx2, Chx10, retinal RAX; Brn3b (necessary for differentiation of retinal ganglion cells); and crx and nrl (role in photoreceptor development). Many cells expressed neuronal markers including nestin, beta-tubulin and microtubule-associated proteins. CONCLUSIONS: This study shows for the first time that 3D early retinal progenitor tissue constructs can be derived from hESCs. PMID: 20447416 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Immunogenicity and allogenicity: a challenge of stem cell therapy. J Cardiovasc Transl Res. 2009 Mar;2(1):130-8 Authors: Charron D, Suberbielle-Boissel C, Al-Daccak R As age progresses, the regenerative power of one's own pluripotent stem cells is often inadequate to sustain normal tissue function. Consequently, the incidence of chronic and degenerative diseases has significantly increased. The derivation of adult tissues and organs from a variety of stem cell sources represents the starting mark for regenerative medicine. It is currently considered a developing mean to repair, restore, maintain, or enhance organ functioning through life span. Recent advances in human embryonic stem cells (hESC) research, however, made the prospect of cell replacement therapy even more compelling and highlighted hESC as a fast track in the therapeutic hope. Among the hurdles which have been largely overlooked in the excitement over the expected benefit is the immunogenicity. Indeed, beyond the clear need to establish the safety of hESC and their derived tissues in terms of tumorogenicity and potential to transmit infections, the challenge is to overcome the immunological barriers to their transplantation. PMID: 20559977 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Panoramic view of the Fifth International Symposium on Stem Cell Therapy and Applied Cardiovascular Biotechnology, April 2008, Madrid (Spain). J Cardiovasc Transl Res. 2009 Mar;2(1):108-13 Authors: Villa A, Sanz R, Fernandez ME, Elizaga J, Ludwig I, Sanchez PL, Fernandez-Aviles F The Fifth International Symposium on Stem Cell Therapy and Applied Cardiovascular Biotechnology was held on April 24th-25th, 2008, at the Auditorium of the High Council of Scientific Research of Spain (CSIC) in Madrid, as a continuation of a series of yearly meetings, organized in an attempt to encourage translational research in this field and facilitate a positive interaction among experts from several countries, along with industry representatives and journalists. In addition, members of the Task Force of the European Society concerning the clinical investigation of the use of autologous adult stem cells for repair of the heart gathered and discussed an update of the previous consensus, still pending of publication. In this article, we summarize some of the main topics of discussion, the state-of-the-art and latest advances in this field, and new challenges brought up for the near future. PMID: 20559974 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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