|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | [Stem cell therapy for neurological disorders.] Ugeskr Laeger. 2010 Sep 20;172(38):2604-2607 Authors: Meyer M, Jensen P, Rasmussen JZ Intrastriatal, foetal neural transplants can ameliorate symptoms in patients with Parkinson's and Huntington's disease, although not stop the primary cell-loss. Several issues must, however, be addressed before general or extended clinical use of cell therapy in neurodegenerative diseases can become a reality. Improvements include standardized and safe master cell-lines derived from human embryonic stem cells, induced pluripotent stem cells and neural stem cells. Cells from these sources are expected to become available for cell replacement therapies or therapeutic production of trophic, anti-inflammatory and restorative factors within a few years. PMID: 20920404 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adipose-derived mesenchymal stem cells markedly attenuate brain infarct size and improve neurological function in rats. J Transl Med. 2010;8:63 Authors: Leu S, Lin YC, Yuen CM, Yen CH, Kao YH, Sun CK, Yip HK BACKGROUND: The therapeutic effect of adipose-derived mesenchymal stem cells (ADMSCs) on brain infarction area (BIA) and neurological status in a rat model of acute ischemic stroke (IS) was investigated. METHODS: Adult male Sprague-Dawley (SD) rats (n = 30) were divided into IS plus intra-venous 1 mL saline (at 0, 12 and 24 h after IS induction) (control group) and IS plus intra-venous ADMSCs (2.0 x 106) (treated interval as controls) (treatment group) after occlusion of distal left internal carotid artery. The rats were sacrificed and brain tissues were harvested on day 21 after the procedure. RESULTS: The results showed that BIA was larger in control group than in treatment group (p < 0.001). The sensorimotor functional test (Corner test) identified a higher frequency of turning movement to left in control group than in treatment group (p < 0.05). mRNA expressions of Bax, caspase 3, interleukin (IL)-18, toll-like receptor-4 and plasminogen activator inhibitor-1 were higher, whereas Bcl-2 and IL-8/Gro were lower in control group than in treatment group (all p < 0.05). Western blot demonstrated a lower CXCR4 and stromal-cell derived factor-1 (SDF-1) in control group than in treatment group (all p < 0.01). Immunohistofluorescent staining showed lower expressions of CXCR4, SDF-1, von Willebran factor and doublecortin, whereas the number of apoptotic nuclei on TUNEL assay was higher in control group than in treatment group (all p < 0.001). Immunohistochemical staining showed that cellular proliferation and number of small vessels were lower but glial fibrillary acid protein was higher in control group than in treatment group (all p < 0.01). CONCLUSIONS: ADMSC therapy significantly limited BIA and improved sensorimotor dysfunction after acute IS. PMID: 20584315 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Addition of hydroxyapatite improves stiffness, interconnectivity and osteogenic potential of a highly porous collagen-based scaffold for bone tissue regeneration. Eur Cell Mater. 2010;20:218-30 Authors: Gleeson JP, Plunkett NA, O'Brien FJ There is an enduring and unmet need for a bioactive, load-bearing tissue-engineering scaffold, which is biocompatible, biodegradable and capable of facilitating and promoting osteogenesis when implanted in vivo. This study set out to develop a biomimetic scaffold by incorporating osteoinductive hydroxyapatite (HA) particles into a highly porous and extremely biocompatible collagen-based scaffold developed within our laboratory over the last number of years to improve osteogenic performance. Specifically we investigated how the addition of discrete quantities of HA affected scaffold porosity, interconnectivity, mechanical properties, in vitro mineralisation and in vivo bone healing potential. The results show that the addition of HA up to a 200 weight percentage (wt%) relative to collagen content led to significantly increased scaffold stiffness and pore interconnectivity (approximately 10 fold) while achieving a scaffold porosity of 99%. In addition, this biomimetic collagen-HA scaffold exhibited significantly improved bioactivity, in vitro mineralisation after 28 days in culture, and in vivo healing of a critical-sized bone defect. These findings demonstrate the regenerative potential of these biodegradable scaffolds as viable bone graft substitute materials, comprised only of bone's natural constituent materials, and capable of promoting osteogenesis in vitro and in vivo repair of critical-sized bone defects. PMID: 20922667 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Image processing and fractal box counting: user-assisted method for multi-scale porous scaffold characterization. J Mater Sci Mater Med. 2010 Oct 5; Authors: Guarino V, Guaccio A, Netti PA, Ambrosio L Image analysis has gained new effort in the scientific community due to the chance of investigating morphological properties of three dimensional structures starting from their bi-dimensional gray-scale representation. Such ability makes it particularly interesting for tissue engineering (TE) purposes. Indeed, the capability of obtaining and interpreting images of tissue scaffolds, extracting morphological and structural information, is essential to the characterization and design of engineered porous systems. In this work, the traditional image analysis approach has been coupled with a probabilistic based percolation method to outline a general procedure for analysing tissue scaffold SEM micrographs. To this aim a case study constituted by PCL multi-scaled porous scaffolds was adopted. Moreover, the resulting data were compared with the outputs of conventionally used techniques, such as mercury intrusion porosimetry. Results indicate that image processing methods well fit the porosity features of PCL scaffolds, overcoming the limits of the more invasive porosimetry techniques. Also the cut off resolution of such IP methods was discussed. Moreover, the fractal dimension of percolating clusters, within the pore populations, was addressed as a good indication of the interconnection degree of PCL bi-modal scaffolds. Such findings represent (i) the bases for a novel approach complementary to the conventional experimental procedure used for the morphological analysis of TE scaffolds, in particular offering a valid method for the analysis of soft materials (i.e., gels); also (ii) providing a new perspective for further studies integrating to the structural and morphological data, fluid-dynamics and transport properties modelling. PMID: 20922560 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Growth of the chorioallantoic membrane into a rapid-prototyped model pore system: experiments and mathematical model. Biomech Model Mechanobiol. 2010 Oct 5; Authors: Lemon G, Howard D, Yang H, Ratchev SM, Segal JI, Rose FR, Jensen OE, Waters SL, King JR This paper presents a mathematical model to describe the growth of tissue into a rapid-prototyped porous scaffold when it is implanted onto the chorioallantoic membrane (CAM). The scaffold was designed to study the effects of the size and shape of pores on tissue growth into conventional tissue engineering scaffolds, and consists of an array of pores each having a pre-specified shape. The experimental observations revealed that the CAM grows through each pore as an intact layer of tissue, provided the width of the pore exceeds a threshold value. Based on these results a mathematical model is described to simulate the growth of the membrane, assuming that the growth is a function of the local isotropic membrane tension. The model predictions are compared against measurements of the extent of membrane growth through the pores as a function of time for pores with different dimensions. PMID: 20922556 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Scaffolds in tissue engineering of blood vessels. Can J Physiol Pharmacol. 2010 Sep;88(9):855-73 Authors: Pankajakshan D, Agrawal DK Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering. PMID: 20921972 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Frontiers of vascular biology and disease research. Acta Pharmacol Sin. 2010 Oct;31(10):1241-2 Authors: Chen AF, Tang CS PMID: 20921953 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cancer stem cells from human breast tumors are involved in spontaneous metastases in orthotopic mouse models. Proc Natl Acad Sci U S A. 2010 Oct 4; Authors: Liu H, Patel MR, Prescher JA, Patsialou A, Qian D, Lin J, Wen S, Chang YF, Bachmann MH, Shimono Y, Dalerba P, Adorno M, Lobo N, Bueno J, Dirbas FM, Goswami S, Somlo G, Condeelis J, Contag CH, Gambhir SS, Clarke MF To examine the role of breast cancer stem cells (BCSCs) in metastasis, we generated human-in-mouse breast cancer orthotopic models using patient tumor specimens, labeled with optical reporter fusion genes. These models recapitulate human cancer features not captured with previous models, including spontaneous metastasis in particular, and provide a useful platform for studies of breast tumor initiation and progression. With noninvasive imaging approaches, as few as 10 cells of stably labeled BCSCs could be tracked in vivo, enabling studies of early tumor growth and spontaneous metastasis. These advances in BCSC imaging revealed that CD44(+) cells from both primary tumors and lung metastases are highly enriched for tumor-initiating cells. Our metastatic cancer models, combined with noninvasive imaging techniques, constitute an integrated approach that could be applied to dissect the molecular mechanisms underlying the dissemination of metastatic CSCs (MCSCs) and to explore therapeutic strategies targeting MCSCs in general or to evaluate individual patient tumor cells and predict response to therapy. PMID: 20921380 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | One-step generation of murine embryonic stem cell-derived mesoderm progenitors and chondrocytes in a serum-free monolayer differentiation system. Stem Cell Res. 2010 Sep 6; Authors: Waese EY, Stanford WL Cartilage defects have limited capacity for repair and are often replaced by fibrocartilage with inferior mechanical properties. To overcome the limitations of artificial joint replacement, high-throughput screens (HTS) could be developed to identify molecules that stimulate differentiation and/or proliferation of articular cartilage for drug therapy or tissue engineering. Currently embryonic stem cells (ESCs) can differentiate into articular cartilage by forming aggregates (embryoid body (EB), pellet, micromass), which are difficult to image. We present a novel, single-step method of generating murine ESC-derived chondrocytes in monolayer cultures under chemically defined conditions. Mesoderm induction was achieved in cultures supplemented with BMP4, activin A, or Wnt3a. Prolonged culture with sustained activin A, TGFβ3, or BMP4 supplementation led to robust chondrogenic induction. A short pulse of activin A or BMP4 also induced chondrogenesis efficiently while Wnt3a acted as a later inducer. Long-term supplementation with activin A or with activin A followed by TGFβ3 promoted articular cartilage formation. Thus, we devised a serum-free (SF) culture system to generate ESC-derived chondrocytes without the establishment of 3D cultures or the aid of cell sorting. Cultures were governed by the same signaling pathways as 3D ESC differentiation systems and limb bud mesenchyme or articular cartilage explant cultures. PMID: 20920900 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Structural and material approaches for bone tissue engineering in powder based 3D printing. Acta Biomater. 2010 Oct 1; Authors: Butscher A, Bohner M, Hoffmann S, Gauckler L, Müller R This article aims at reviewing the current state of knowledge concerning the use of powder-based three-dimensional printing (3DP) for the synthesis of bone tissue engineering scaffolds. 3DP is a solid free-form (SFF) technique building up complex open porous 3D structures layer by layer (bottom-up approach). In contrast to traditional fabrication techniques generally subtracting material step by step (top-down approach), SFF approaches allow nearly unlimited designs and large varieties of materials suitable for scaffold engineering. The today's state of the art materials' as well as mechanical and structural requirements for bone scaffolds are summarized and discussed in relation with technical feasibility within 3DP. Advances in the field of 3DP are presented and compared to other SFF methods. Existing strategies on material and design control of scaffolds are reviewed. Finally possibilities and limiting factors are addressed and potential strategies to improve 3DP for scaffold engineering are proposed. PMID: 20920616 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The Wnt signaling pathway in Cellular Proliferation and Differentiation: A tale of two coactivators. Adv Drug Deliv Rev. 2010 Oct 1; Authors: Teo JL, Kahn M Wnt signaling pathways play divergent roles during development, normal homeostasis and disease. The responses that result from the activation of the pathway control both proliferation and differentiation. Tight regulation and controlled coordination of the Wnt signaling cascade is required to maintain the balance between proliferation and differentiation. The non-redundant roles of the coactivator proteins CBP and p300, within the context of Wnt signaling are discussed.We highlight their roles as integrators of the various inputs that a cell receives to elicit the correct and coordinated response. We propose that essentially all cellular information - i.e. from other signaling pathways, nutrient levels, etc. - is funneled down into a choice of coactivators usage, either CBP or p300, by their interacting partner beta-catenin (or catenin-like molecules in the absence of beta-catenin) to make the critical decision to either remain quiescent, or once entering cycle to proliferate without differentiation or to initiate the differentiation process. PMID: 20920541 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue Engineering Approaches to Enhancing Clinical Islet Transplantation through Tissue Engineeering Strategies. J Diabetes Sci Technol. 2010;4(5):1238-47 Authors: Giraldo JA, Weaver JD, Stabler CL Clinical islet transplantation (CIT), the infusion of allogeneic islets within the liver, has the potential to provide precise and sustainable control of blood glucose levels for the treatment of type 1 diabetes. The success and long-term outcomes of CIT, however, are limited by obstacles such as a nonoptimal transplantation site and severe inflammatory and immunological responses to the transplant. Tissue engineering strategies are poised to combat these challenges. In this review, emerging methods for engineering an optimal islet transplantation site, as well as novel approaches for improving islet cell encapsulation, are discussed. PMID: 20920446 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Importance of interleukin-1 and interleukin-1 receptor antagonist in short-term glucose sensor function in vivo. J Diabetes Sci Technol. 2010;4(5):1073-86 Authors: Klueh U, Liu Z, Feldman B, Kreutzer D BACKGROUND: The importance of the interleukin (IL)-1 cytokine family in inflammation and immunity is well established as a result of extensive in vitro and in vivo studies. In fact, much of our understanding of the in vivo importance of interleukin-1beta (IL-1B) is the result of research utilizing transgenic mice, such as overexpression or deficiencies of the naturally occurring inhibitor of IL-1 known as interleukin-1 receptor antagonist (IL-1RA). For the present studies, we utilized these transgenic mice to determine the role of IL-1B in glucose sensor function in vivo. METHODS: To investigate the role of IL-1B in glucose sensor function in vivo, we compared glucose sensor function in trans-genic mice that (1) overexpressed IL-1RA [B6.Cg-Tg(II1rn)1Dih/J] and (2) are deficient in IL-1RA (B6.129S-Il1rn(tm1Dih)/J), with mice that have normal levels of IL-1RA (C57BL/6). RESULTS: Our studies demonstrated that, during the first 7 days post-sensor implantation (PSI), mice deficient in IL-1RA had extensive inflammation and decreased sensor function when compared to normal or IL-1RA-overexpressing mice. CONCLUSION: These data directly support our hypothesis that the IL-1 family of cytokines and antagonists play a critical role in controlling tissue reactions and thereby sensor function in vivo during the first 7 days PSI. PMID: 20920427 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | [Bone and cartilage repair using stem cells.] Ugeskr Laeger. 2010 Sep 20;172(38):2616-2619 Authors: Larsen KH, Andersen TE, Kassem M Mesenchymal stem cells (MSC) are capable of multilineage differentiation into cells like osteoblasts, chrondrocytes or adipocytes. MSCs can be isolated from bone marrow and expanded ex vivo for up to 25-40 population doublings while maintaining genetic stability and differentiation potential. MSCs have great potential in the field of tissue engineering and regenerative medicine where cartilage and bone conditions which are non-treatable or show very slow improvement can be effectively handled. Several clinical trials have been performed using MSC and show very promising results. PMID: 20920407 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [An introduction to stem cell research.] Ugeskr Laeger. 2010 Sep 20;172(38):2594-2597 Authors: Jensen PL, Wegeberg JP, Andersen CY Stem cells (SC) are characterized by the ability of self renewal as well as specialization into different cell types. Stem cells are present in most organs, and can be isolated from adult tissue, embryonic tissue and can be created by a new technology named induced pluripotency. The three types of SC have different potentials in terms of advancing regenerative medicine, but also raise serious safety concerns that need to be addressed before SC can fulfill the expectations by being developed into new cures and treatments for a range of serious cell degenerative diseases. PMID: 20920401 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of the osteogenic and chondrogenic differentiation capacities of equine adipose tissue-derived mesenchymal stem cells. Am J Vet Res. 2010 Oct;71(10):1228-36 Authors: Braun J, Hack A, Weis-Klemm M, Conrad S, Treml S, Kohler K, Walliser U, Skutella T, Aicher WK Objective—To evaluate the proliferative behavior, telomere length, immunophenotype, and differentiation capacity of equine adipose tissue-derived mesenchymal stem cells (AT-MSCs). Animals—6 adult racing horses treated for articular Injury but otherwise healthy Procedures—AT-MSCs were Isolated from horses and expanded In Dulbecco modified Eagle medium enriched with fetal bovine serum and antimicrobials. Expression of cell surface antigens and telomere length were Investigated via flow cytometry Differentiation of MSCs Into chondrocytes, osteoblasts, and adipocytes was Induced In vitro by specific stimuli and was evaluated by analyzing marker genes with quantitative reverse transcriptase PCR assays and immunocytochemical and cytologie evaluations. Results—Equine MSCs could be cultured up to the fifth passage before signs of senescence, apoptosis, and detachment Indicated cellular exhaustion. However, the AT-MSCs from 2 of 6 horses survived to later passages with Increased doubling rates and telomere lengths. The cells had a typical phenotype, with expression of CD14, CD73, CD90, CD105, CD140b, and CD164 antigens and a lack of CD34 and CD45 antigens. The cells also had a strong potential to differentiate Into osteoblasts, as characterized by Intense von Kossa and alizarin red staining as well as high Induction of osteopontin. Chondrogenic differentiation was detected via Alelan blue staining and expression of aggrecan and type II collagen Adipogenesis was Induced in AT-MSCs by supplementation of differentiation media with rabbit serum. Conclusions and Clinical Relevance—Equine AT-MSCs representa suitable cellular source for regenerative treatment of bone or cartilage defects, particularly when expanded In vitro for only a few passages. (Am J Vet Res 2010;71:1228-1236). PMID: 20919912 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Engineered Biocompatible Nanoparticles for in Vivo Imaging Applications. J Am Chem Soc. 2010 Oct 4; Authors: Chen S, Wang L, Duce SL, Brown S, Lee S, Melzer A, Cuschieri SA, André P Iron-platinum alloy nanoparticles (FePt NPs) are extremely promising candidates for the next generation of contrast agents for magnetic resonance (MR) diagnostic imaging and MR-guided interventions, including hyperthermic ablation of solid cancers. FePt has high Curie temperature, saturation magnetic moment, magneto-crystalline anisotropy, and chemical stability. We describe the synthesis and characterization of a family of biocompatible FePt NPs suitable for biomedical applications, showing and discussing that FePt NPs can exhibit low cytotoxicity. The importance of engineering the interface of strongly magnetic NPs using a coating allowing free aqueous permeation is demonstrated to be an essential parameter in the design of new generations of diagnostic and therapeutic MRI contrast agents. We report effective cell internalization of FePt NPs and demonstrate that they can be used for cellular imaging and in vivo MRI applications. This opens the way for several future applications of FePt NPs, including regenerative medicine and stem cell therapy in addition to enhanced MR diagnostic imaging. PMID: 20919679 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | In-vitro seeding of human umbilical cord vein endothelial cells on hydroxyapatite for mechanical heart valve applications. J Heart Valve Dis. 2010 Jul;19(4):506-12 Authors: Sha JM, Yan ZY, Cheng GC, Weil XY, Tao YQ, Li YM, Luo L BACKGROUND AND AIM OF THE STUDY: Although heart valve replacement with either a mechanical or biological prosthesis is an effective method to treat valvular heart disease, both approaches have limitations, including thrombus formation, thromboembolism and degeneration problems. The study aim was to demonstrate the in-vitro endothelialization of hydroxyapatite (HAp) to be used as a biomaterial in heart valve prostheses. METHODS: The HAp samples were characterized using X-ray diffractometry to identify the crystalline phase, while the surface morphology of HAp discs was examined using scanning electron microscopy (SEM). Human umbilical vein endothelial cells (HUVECs) were cultured on HAp discs for 1, 3, 5, and 7 days, and on pyrolytic carbon discs for 7 days; cytotoxicity was assessed using the methyl thiazolyl tetrazolium (MTT) assay. The cells were incubated in three groups: (i) an experimental group (cultured with HAp extract); (ii) a negative control (cultured with high-density polyethylene chaff); and (iii) a positive control (culture medium containing 0.1% phenol solution). RESULTS: A morphological examination of the HAp discs revealed the presence of micropores on the disc surface, together with cultured HUVECs. After seven days of culture, the HUVECs began to form a confluent endothelial cell layer covering the HAp discs. There were no visible cells attached to the pyrolytic carbon surface. The MTT assay indicated that HAp did not exert any cytotoxic effect on HUVECs, and low optical density values were obtained in the positive controls. CONCLUSION: The study results showed that HUVECs were able to grow well on HAp discs, and that HAP possessed a good in-vitro bioactivity and biocompatibility towards these cells. Consequently, HAp might be used as a film on mechanical heart valve prostheses, and serve as a promising biomaterial for heart valve replacement. PMID: 20845900 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Modulation of the major histocompatibility complex by neural stem cell-derived neurotrophic factors used for regenerative therapy in a rat model of stroke. J Transl Med. 2010;8:77 Authors: Sun C, Zhang H, Li J, Huang H, Cheng H, Wang Y, Li P, An Y BACKGROUND: The relationship between functional improvements in ischemic rats given a neural stem cell (NSC) transplant and the modulation of the class I major histocompatibility complex (MHC) mediated by NSC-derived neurotrophins was investigated. METHODS: The levels of gene expression of nerve growth factor (NGF), brain-derived neurotropic factor (BDNF) and neurotrophin-3 (NT-3) were assayed from cultures of cortical NSC from Sprague-Dawley rat E16 embryos. The levels of translated NGF in spent culture media from NSC cultures and the cerebral spinal fluid (CSF) of rats with and without NGF injection or NSC transplant were also measured. RESULTS: We found a significant increase of NGF, BDNF and NT-3 transcripts and NGF proteins in both the NSC cultures and the CSF of the rats. The immunochemical staining for MHC in brain sections and the enzyme-linked immunosorbent assay of CSF were carried out in sham-operated rats and rats with surgically induced focal cerebral ischemia. These groups were further divided into animals that did and did not receive NGF administration or NSC transplant into the cisterna magna. Our results show an up-regulation of class I MHC in the ischemic rats with NGF and NSC administration. The extent of caspase-III immunoreactivity was comparable among three arms in the ischemic rats. CONCLUSION: Readouts of somatosensory evoked potential and the trap channel test illustrated improvements in the neurological function of ischemic rats treated with NGF administration and NSC transplant. PMID: 20727165 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Human or animal homograft: could they have a future as a biological scaffold for engineered heart valves? J Cardiovasc Surg (Torino). 2010 Jun;51(3):449-56 Authors: Dainese L, Biglioli P Tissue-engineered heart valves (TEHVs) promise to be the ideal heart valve replacement: they have the potential to grow and repair within the host, to minimise inflammatory and immunological responses and to limit thromboembolism. Viable cells included in TEHVs can theoretically adapt to a growing and changing environment exactly as a native biological structure. This could be extremely important in case of paediatric applications, where reoperations are frequently required to replace failed valve substitutes or to accommodate the growth of the patient. At present time the biological matrix from allogenic or xenogenic decellularized valves represents an appropriate valve scaffold in TEHVs, showing theoretically an ability to grow and repair within the host. Viable cells included in extracellular valve matrix can theoretically adapt to a growing and changing environment like the native biological structure. The aim of this paper is to present a review concerning the use of homograft and allograft valves as an ideal substrate for cardiac engineered tissue valves that represent an exciting possibility for in situ regeneration and repair of heart valves. PMID: 20523298 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [Study on the influence of the configuration of porcine aortic root on the stentless valve design] Zhonghua Wai Ke Za Zhi. 2009 Sep 1;47(17):1336-9 Authors: Wu F, Wei XF, Yi DH, Tan HM, Xu S, Liu WY OBJECTIVE: To provide the reference for the stentless aortic valve design with the study of the inner configuration of porcine aortic root. METHODS: The orifice areas of porcine aortic root at 4 levels (OA1 to 4), the average area of leaflets (Sa), the area analogue of leaflets (AA, AA = 1/2PH), the average area analogue of leaflets (AAa), the value PH of the left, right, non coronary leaflets (PHl, PHr, PHn) and the sums of PHs of the left and non-coronary leaflets (PHln) in the fresh and glutaraldehyde and epichlorohydrin-treated porcine aortic valves (20 respectively) were measured and calculated. The linear correlation and regression analysis by SPSS 12.0 was used to analyze the correlation between Sa and AAa, OA and Sa, OA and AAa, PHl, PHr and PHn, PHln and PHr in both groups. RESULTS: The coefficient correlation between Sa and AAa in fresh and treated groups were 0.886 and 0.872 respectively (P < 0.05). The coefficient correlation between OA1 to 4 and AAa were 0.810, 0.851, 0.900, and 0.815 respectively in fresh group (P < 0.05), and were 0.852, 0.888, 0.836, and 0.817 respectively in treated group (P < 0.05). This showed that the degree of correlation between the average area analogue of leaflets and the average area of leaflets, the orifice areas of aortic root were relatively large. Additionally, the equation of linear regression existed between PHln and PHr in treated group as follows: PHr = -1.665 + 0.688 PHln (r = 0.907, P < 0.05), thereby PHr could be predicted by PHln. CONCLUSION: The value of PH of leaflets could represent the spatial configuration of the aortic root, which provided a referred index for the stentless bioprostheses design. PMID: 20092732 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Hematopoietic stem cell: self-renewal versus differentiation. Wiley Interdiscip Rev Syst Biol Med. 2010 Nov-Dec;2(6):640-53 Authors: Seita J, Weissman IL The mammalian blood system, containing more than 10 distinct mature cell types, stands on one specific cell type, hematopoietic stem cell (HSC). Within the system, only HSCs possess the ability of both multipotency and self-renewal. Multipotency is the ability to differentiate into all functional blood cells. Self-renewal is the ability to give rise to HSC itself without differentiation. Since mature blood cells (MBCs) are predominantly short-lived, HSCs continuously provide more differentiated progenitors while properly maintaining the HSC pool size throughout life by precisely balancing self-renewal and differentiation. Thus, understanding the mechanisms of self-renewal and differentiation of HSC has been a central issue. In this review, we focus on the hierarchical structure of the hematopoietic system, the current understanding of microenvironment and molecular cues regulating self-renewal and differentiation of adult HSCs, and the currently emerging systems approaches to understand HSC biology. Copyright © 2010 John Wiley & Sons, Inc.For further resources related to this article, please visit the WIREs website. PMID: 20890962 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | An exopolysaccharide produced by the novel halophilic bacterium Halomonas stenophila strain B100 selectively induces apoptosis in human T leukaemia cells. Appl Microbiol Biotechnol. 2010 Oct 3; Authors: Ruiz-Ruiz C, Srivastava GK, Carranza D, Mata JA, Llamas I, SantamarÃa M, Quesada E, Molina IJ Microbial exopolysaccharides (EPSs) are highly heterogeneous polymers produced by fungi and bacteria and have recently been attracting considerable attention from biotechnologists because of their potential applications in many fields, including biomedicine. We have screened the antitumoural activity of a panel of sulphated EPSs produced by a newly discovered species of halophilic bacteria. We found that the novel halophilic bacterium Halomonas stenophila strain B100 produced a heteropolysaccharide that, when oversulphated, exerted antitumoural activity on T cell lines deriving from acute lymphoblastic leukaemia (ALL). Only tumour cells were susceptible to apoptosis induced by the sulphated EPS (B100S), whilst primary T cells were resistant. Moreover, freshly isolated primary cells from the blood of patients with ALL were also susceptible to B100S-induced apoptosis. The newly discovered B100S is therefore the first bacterial EPS that has been demonstrated to exert a potent and selective pro-apoptotic effect on T leukaemia cells, and thus, we propose that the search for new antineoplastic drugs should include the screening of other bacterial EPSs, particularly those isolated from halophiles. PMID: 20890756 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nano-hydroxyapatite/poly(L: -lactic acid) composite synthesized by a modified in situ precipitation: preparation and properties. J Mater Sci Mater Med. 2010 Oct 2; Authors: Zhang CY, Lu H, Zhuang Z, Wang XP, Fang QF Nano-hydroxyapatite/poly(L: -lactic acid) (nano-HA/PLLA) composites with uniform HA distribution and good mechanical performance were fabricated by a modified in situ precipitation method, using Ca(OH)(2) and H(3)PO(4) as precursors for the synthesis of HA phase. This method has solved the aggregation problem of the nano-sized particles in the polymer matrix. The X-ray diffraction, Fourier transform infrared spectroscopy, and transmission electron microscopy were used to characterize the phase composition, chemical interactions and morphology of the composites, while the mechanical properties were determined by compressive measurements. The results show that the rod-like nano-HA particles synthesized by this method were uniformly distributed in the PLLA matrix. The compressive strength and Young's modulus of the composites were greatly enhanced and reached the values of 155 MPa and 3.6 GPa at 20 wt% HA content, respectively, which are much higher than those of the reference samples fabricated by direct mixing of PLLA with nano-HA particles. This supports the potential of these composites for applications in bone tissue engineering and load bearing bone defects repair. PMID: 20890640 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Transplantation of patient-derived adipose stem cells in YAC128 Huntington's disease transgenic mice. PLoS Curr. 2010;2 Authors: Im W, Lee ST, Park JE, Oh HJ, Shim J, Lim J, Chu K, Kim M Huntington's disease (HD) is a genetic neurodegenerative disorder caused by abnormal expansion of CAG in the huntingtin gene. In R6/2 HD transgenic mice, human adipose-derived stem cells (ASCs) can slow disease progression via secretion of multiple paracrine growth factors. In order to prompt autologous ASCs transplantation in HD, we isolated ASCs from subcutaneous adipose tissues from a HD patient and a normal volunteer. ASCs were grown in two different types of stem cell culture media, EGM-2MV (endothelial growth medium-2 MV) or mesenchymal culture medium (MesenPRO). Cell-surface markers CD13, CD29, CD31, CD34, and CD44 were characterized by flow cytometry. BDNF, HGF, IGF, LIF, NGF, and VEGF expressions were determined by RT-PCR. Cell surface markers for HD ASCs were similar to those for normal ASCs. HD ASCs expressed multiple growth factors, and were similar to normal ASCs, except for NGF; however, they can be altered by culture medium. ASCs were transplanted in bilateral striata of 8 month-old YAC128 mice. At 12 months of age, normal ASCs reduced striatal atrophy, while HD ASCs failed to prevent it. Compared to the control YAC128 group, no improvement in Rotarod performance was observed in any of the transplanted YAC128 mice. However, when normal ASCs were transplanted at 12 months, Rotarod performance was maintained for 4 weeks, with detectable transplanted cells in the striatum and periventricular area. In summary, cultured HD patient-derived ASCs express multiple growth factors with the same cell surface markers as those of normal ASCs in vitro. The efficacy of ASCs transplantation in YAC128 transgenic models can be modified, depending on the time window. PMID: 20890444 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Mediators leading to fibrosis - how to measure and control them in tissue engineering. Oper Tech Orthop. 2010 Jun 1;20(2):110-118 Authors: Mu X, Bellayr I, Walters T, Li Y Fibrosis is the result of an excessive amount of fibrous connective tissue deposited into the extracellular matrix (ECM) space of damaged tissues from injury or disease. Collagens, particularly types I and III are the main constituents of the fibrotic scar tissue as well as a mixture of fibrotic cells. Severely fibrotic tissue will develop chronic healing problems resulting in tissue/organ dysfunction. More attention needs to be given to the fibrotic differentiation and related effects in bioengineered tissues. The current review provides an update on the mechanism behind fibrosis formation as well as technical measurements and preventions. PMID: 20890400 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage. Nat Biotechnol. 2010 Oct 3; Authors: Wong CC, Loewke KE, Bossert NL, Behr B, De Jonge CJ, Baer TM, Pera RA We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction. PMID: 20890283 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Substrate elasticity provides mechanical signals for the expansion of hemopoietic stem and progenitor cells. Nat Biotechnol. 2010 Oct 3; Authors: Holst J, Watson S, Lord MS, Eamegdool SS, Bax DV, Nivison-Smith LB, Kondyurin A, Ma L, Oberhauser AF, Weiss AS, Rasko JE Surprisingly little is known about the effects of the physical microenvironment on hemopoietic stem and progenitor cells. To explore the physical effects of matrix elasticity on well-characterized primitive hemopoietic cells, we made use of a uniquely elastic biomaterial, tropoelastin. Culturing mouse or human hemopoietic cells on a tropoelastin substrate led to a two- to threefold expansion of undifferentiated cells, including progenitors and mouse stem cells. Treatment with cytokines in the presence of tropoelastin had an additive effect on this expansion. These biological effects required substrate elasticity, as neither truncated nor cross-linked tropoelastin reproduced the phenomenon, and inhibition of mechanotransduction abrogated the effects. Our data suggest that substrate elasticity and tensegrity are important mechanisms influencing hemopoietic stem and progenitor cell subsets and could be exploited to facilitate cell culture. PMID: 20890282 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Cytokines in bone diseases. Genetic defects of PTH÷PTHrP receptor in chondrodysplasia.] Clin Calcium. 2010 Oct;20(10):1481-8 Authors: Ogata N Parathyroid hormone-related protein (PTHrP) signaling plays important roles in regulating the differentiation of chondrocytes in endochondral bone development. PTHrP signaling functions as an inhibitory effect on chondrocyte hypertrophy which is a terminal stage of differentiation at a growth plate. Mutations of the PTH÷PTHrP receptor have been identified in Jansen metaphyseal chondrodysplasia, Blomstrand's lethal chondrodysplasia, and enchondromatosis. Furthermore, genetic manipulations of the PTHrP and its receptor genes in mice have demonstrated the critical roles of these proteins in regulating both the switch between proliferation and differentiation of chondrocytes. PMID: 20890029 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | SDF-1:CXCR4 Axis Is Fundamental for Tissue Preservation and Repair. Am J Pathol. 2010 Oct 1; Authors: Penn MS This Commentary discusses the role of the SDF-1:CXCR4 axis in tissue preservation and repair. PMID: 20889567 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Intravenous Infusion of GDNF Gene-Modified Human Umbilical Cord Blood CD34+ Cells Protects Against Cerebral Ischemic Injury in Spontaneously Hypertensive Rats. Brain Res. 2010 Sep 30; Authors: Ou Y, Yu S, Kaneko Y, Tajiri N, Bae EC, Chheda SH, Stahl CE, Yang T, Fang L, Hu K, Borlongan CV, Yu G This study assessed the potential of intravenous transplantation of human umbilical cord blood (HUCB) CD34+ cells transfected with glial cell line-derived neurotrophic factor (GDNF) gene to exert therapeutic benefits in spontaneous hypertensive rats (SHR) exposed to transient middle cerebral artery occlusion (MCAO). SHR with MCAO were randomly assigned to receive intravenously transplantation of vehicle, the plasmid containing the enhanced green fluorescent protein (pEGFP)-CD34+ cells or pEGFP-GDNF-CD34+cells at 6 hours after stroke. The CD34+ cells transfected with GDNF gene expressed higher levels of GDNF mRNA and protein than nontransfected HUCB CD34+ cells in vitro. At 28 days after transplantation of GDNF gene modified CD34+ cells, significantly more GFP positive cells, neurons, and astrocytes, likely derived from the grafted cells, populated the peri-infarct area compared to those injected with pEGFP-CD34+ cells or vehicle. Furthermore, the stroke animals transplanted with GDNF gene modified CD34+ cells showed a significant increase in GDNF level in the infarcted hemisphere, reduced brain infarction volume, and enhanced functional recovery compared with those that received pEGFP-CD34+cells. This study supports the use of a combined gene and stem cell therapy for treating stroke. PMID: 20888805 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The Impact of Muscle Disuse on Muscle Atrophy in Severely Burned Rats. J Surg Res. 2010 Sep 15; Authors: Wu X, Baer LA, Wolf SE, Wade CE, Walters TJ BACKGROUND: Severe burn induces a sustained hypermetabolic response, which causes long-term loss of muscle mass and decrease in muscle strength. In this study, we sought to determine whether muscle disuse has additional impact on muscle atrophy after severe burn using a rat model combining severe cutaneous burn and hindlimb unloading. METHODS: Forty Sprague-Dawley rats (≈300 g) were randomly assigned to sham ambulatory (S/A), sham hindlimb unloading (S/HLU), burn ambulatory (B/A), or burn hindlimb unloading (B/HLU) groups. Rats received a 40% total body surface (TBSA) full thickness scald burn, and rats with hindlimb unloading were placed in a tail traction system. At d 14, lean body mass (LBM) was determined using DEXA scan, followed by measurement of the isometric mechanical properties in the predominantly fast-twitch plantaris muscle (PL) and the predominantly slow-twitch soleus muscle (SL). Muscle weight (wt), protein wt, and wet/dry wt were determined. RESULTS: At d 14, body weight had decreased significantly in all treatment groups; B/HLU resulted in significantly greater loss compared with the B/A, S/HLU, and S/A. The losses could be attributed to loss of LBM. PL muscle wt and Po were lowest in the B/HLU group (<0.05 versus S/A, S/HLU, or B/A). SL muscle wt and Po were significantly less in both S/HLU and B/HLU compared with that of S/A and B/A; no significant difference was found between S/HLU and B/HLU. CONCLUSIONS: Cutaneous burn and hindlimb unloading have an additive effect on muscle atrophy, characterized by loss of muscle mass and decrease in muscle strength in both fast (PL) and slow (SL) twitch muscles. Of the two, disuse appeared to be the dominant factor for continuous muscle wasting after acute burn in this model. PMID: 20888588 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Resistance to Infection of Five Different Materials in a Rat Body Wall Model. J Surg Res. 2010 Sep 17; Authors: Medberry CJ, Tottey S, Jiang H, Johnson SA, Badylak SF BACKGROUND: Infection occurs after approximately 1% of hernia repair procedures. The resistance to infection of the repair materials is therefore an important consideration. We evaluated the infection resistance of five different materials in a rat model of body wall repair, two of which, urinary bladder matrix (UBM-ECM) and Revive, were not previously evaluated in a controlled model of infection. MATERIALS AND METHODS: An inoculum of 1 × 10(8) colony forming units of Staphylococcus aureus was delivered to the wound site following implantation of an autograft, UBM-ECM, Proceed, Prolene, or Revive. Infection was monitored by white blood cell counts, body temperature, bacterial culture, and histomorphologic analysis of the implant site. RESULTS: Infection was shown in all groups through increased white blood cell count and body temperature. Animals with UBM-ECM returned to pre-surgery body temperature before all other groups. Substantial bacterial clearance was found in the autograft, UBM-ECM, and Prolene. Histomorphologic analysis showed evidence for persistent bacterial infection in Prolene, Proceed, and Revive 28 d after implantation, whereas the autograft and UBM-ECM appeared free of infection. The autograft showed a pyogranulomatous inflammatory reaction at 28 d while UBM-ECM was similar to uninfected controls. CONCLUSIONS: Superior infection resistance was shown by UBM-ECM compared with the other materials, which were substantially equivalent. Histomorphologic analysis clearly showed an increased ability to resist persistent bacterial infection for UBM-ECM. Our results suggest UBM-ECM may be useful as a repair material in areas of high risk for infection. PMID: 20888581 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of Hyaluronic Acid-Protein Conjugates for Polymer Masked-Unmasked Protein Therapy. Int J Pharm. 2010 Sep 29; Authors: Ferguson EL, Alshame AM, Thomas DW Bioresponsive polymers may effectively be utilized to enhance the circulation time and stability of biologically active proteins and peptides, while reducing their immunogenicity and toxicity. Recently, dextrin-epidermal growth factor (EGF) conjugates, which make use of the Polymer-masked UnMasked Protein Therapy (PUMPT) concept, have been developed and shown potential as modulators of impaired wound healing. This study investigated the potential of PUMPT using hyaluronic acid (HA) conjugates to mask activity and enhance protein stability, while allowing restoration of biological activity following triggered degradation. HA fragments (Mw ∼90,000g/mol), obtained by acid hydrolysis of Rooster comb HA, were conjugated to trypsin as a model enzyme or to EGF as a model growth factor. Conjugates contained 2.45 and 0.98% w/w trypsin or EGF, respectively, and contained<5% free protein. HA conjugation did not significantly alter trypsin's activity. However, incubation of the conjugate with physiological concentrations of HAase increased its activity to ∼145% (p<0.001) that of the free enzyme. In contrast, when HA-EGF conjugates were tested in vitro, no effect on cell proliferation was seen, even in the presence of HAase. HA conjugates did not display typical masking/unmasking behavior, HA-trypsin conjugates exhibited ∼ 52% greater stability in the presence of elastase, compared to free trypsin, demonstrating the potential of HA conjugates for further development as modulators of tissue repair. PMID: 20888405 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Interactions of heat shock protein 47 with collagen and the stress response: An unconventional chaperone model? Life Sci. 2010 Sep 29; Authors: Mala JG, Rose C Heat shock proteins (HSPs) are upregulated and manifested upon cellular stress and possess chaperoning functions. HSP47 is an endoplasmic reticulum (ER)-resident, collagen-specific chaperone and plays a key role in collagen biosynthesis and its structural assembly. The collagen scaffold is a primary structural target of recent interest due to its applications in tissue engineering and drug delivery and in treatment of clinical disorders. This review highlights the fundamental aspects of HSPs in protein folding and quality control, in the elicitation of a stress response in connective tissue and in the characterization of HSP47 in collagen folding and assembly. The significant features of HSP47 which are distinct in its cellular capabilities are discussed. We propose that targeting the stress response is a key factor in identifying connective tissue biomarkers. We also address the issues and strategies involved in the stress response of connective tissues diseases. In conclusion, we describe the prospects of collagen biochemistry in correlation to the science of HSPs. PMID: 20888348 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Highly Efficient Reprogramming to Pluripotency and Directed Differentiation of Human Cells with Synthetic Modified mRNA. Cell Stem Cell. 2010 Sep 29; Authors: Warren L, Manos PD, Ahfeldt T, Loh YH, Li H, Lau F, Ebina W, Mandal PK, Smith ZD, Meissner A, Daley GQ, Brack AS, Collins JJ, Cowan C, Schlaeger TM, Rossi DJ Clinical application of induced pluripotent stem cells (iPSCs) is limited by the low efficiency of iPSC derivation and the fact that most protocols modify the genome to effect cellular reprogramming. Moreover, safe and effective means of directing the fate of patient-specific iPSCs toward clinically useful cell types are lacking. Here we describe a simple, nonintegrating strategy for reprogramming cell fate based on administration of synthetic mRNA modified to overcome innate antiviral responses. We show that this approach can reprogram multiple human cell types to pluripotency with efficiencies that greatly surpass established protocols. We further show that the same technology can be used to efficiently direct the differentiation of RNA-induced pluripotent stem cells (RiPSCs) into terminally differentiated myogenic cells. This technology represents a safe, efficient strategy for somatic cell reprogramming and directing cell fate that has broad applicability for basic research, disease modeling, and regenerative medicine. PMID: 20888316 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Basement of matrix therapy in regenerative medicine by RGTA(®): From fundamental to plastic surgery.] Ann Chir Plast Esthet. 2010 Sep 29; Authors: Barritault D, Garcia-Filipe S, Zakine G Cells present continuous renewal, permitting permanent regeneration which is called tissue homeostasis. The signaling protein, known as growth factors, cytokines, interleukins and chemokines, but also the extracellular matrix play a key role in the cellular communication. All processes are deregulated after tissue injury, inducing scars. By reconstituting the extracellular matrix, it is possible to avoid the development of scar and to favorize the regeneration of the injured tissue. Glycosaminoglycans, and particularly heparan sulfates, by participating to the extracellular matrix structure, are implicated in cellular communication. This article describes how, by creating heparan sulfate mimetic or Regenerating Agent (RGTA), a French academic team has demonstrated that mammals have the ability to regenerate, by restoring the proper cellular micro-environment. After a first clinical development in two severe and chronic pathologies (corneal and skin ulcers), we show now the potential of these agents in plastic and reconstructive surgery, to regulate fibrosis and to enhance speed and quality of tissue healing. PMID: 20888111 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional culture of rat BMMSCs in a porous chitosan-gelatin scaffold: A promising association for bone tissue engineering in oral reconstruction. Arch Oral Biol. 2010 Sep 29; Authors: Miranda SC, Silva GA, Hell RC, Martins MD, Alves JB, Goes AM OBJECTIVE: This study investigated the in vitro effects of a chitosan-gelatin scaffold on growth and osteogenic differentiation of rat bone marrow mesenchymal stem cells (BMMSCs) in three-dimensional (3D) cultures and evaluated the biomaterial biocompatibility and degradability after its grafting into tooth sockets of rats. DESIGN: A porous chitosan-gelatin scaffold cross-linked by glutaraldehyde was synthesised and characterised by light (LM), scanning electronic microscopy (SEM), energy dispersion spectroscopy (EDS) and X-ray diffraction (XRD). Rat BMMSCs were isolated, expanded and seeded onto scaffold using Dulbecco's Modified Eagle's Medium (DMEM) with or without an osteogenic supplement. Cell viability by MTT assay, alkaline phosphatase (ALP) activity and morphological LM and SEM analysis were performed after 1, 3, 8 and 14 days in culture. Free-cell scaffolds were implanted into tooth sockets of Lewis rats after upper first molars extraction. Fifteen male recipient rats were sacrificed after 5, 21 and 35 days for histological analysis. RESULTS: Scaffold characterisation revealed the porous structure, organic and amorphous content. This biomaterial promoted the adhesion, spreading and in vitro viability of the BMMSCs. Osteogenic-supplemented media did not improve the cellular response compared to DMEM. The biomaterial presented high biocompatibility and slow biodegradation in vivo. Remains of biomaterial were still observed at 21 and 35 days after implantation. However, on the 21st day, alveolar bone and epithelial healing were completely established. CONCLUSIONS: These results indicate that chitosan-gelatin support the adhesion and osteogenic differentiation of rat BMMSCs and offer adequate physico-chemical and biological properties for use as scaffolds in bone tissue engineering-related strategies. PMID: 20887975 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell therapies in clinical trials: workshop on best practices and the need for harmonization. Cell Stem Cell. 2010 Oct 8;7(4):451-4 Authors: Martell K, Trounson A, Baum E A workshop addressing regulation of clinical implementation of stem cell therapies preceded the ISSCR 8(th) Annual Meeting, cosponsored by the International Society for Stem Cell Research, the California Institute for Regenerative Medicine and the International Society for Cellular Therapy. PMID: 20887951 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Altering cell fate: from thymus epithelium to skin stem cells. Cell Stem Cell. 2010 Oct 8;7(4):419-20 Authors: Bilousova G, Roop DR In a recent study in Nature, Bonfanti et al. (2010) report that the skin microenvironment can convert thymic epithelial cells into skin stem cells. This finding suggests that somatic stem cells may have a broader potential for lineage switching than previously thought. PMID: 20887943 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The majority of US combat casualty soft-tissue wounds are not infected or colonized upon arrival or during treatment at a continental US military medical facility. Am J Surg. 2010 Oct;200(4):489-95 Authors: Sheppard FR, Keiser P, Craft DW, Gage F, Robson M, Brown TS, Petersen K, Sincock S, Kasper M, Hawksworth J, Tadaki D, Davis TA, Stojadinovic A, Elster E BACKGROUND: The microbiology of war wounds has changed as medicine and warfare have evolved. This study was designed to determine the microbial flora and bacterial quantification of present-day war wounds in US troops from Iraq and Afghanistan upon arrival at the National Naval Medical Center (NNMC). METHODS: Patients with extremity combat wounds treated with a vacuum-assisted wound closure device were enrolled in study. Wounds were biopsied every 48 to 72 hours with quantitative microbiology performed on all biopsies. RESULTS: Two hundred forty-two wound biopsies from 34 patients; 167 (69%) showed no growth, and 75 (31%) showed positive growth. The incidence of any bacterial isolation from biopsies weekly from the time of injury was 28% (first), 31% (second), and 37% (≥third). Acinetobacter baumannii was the most prevalent isolate. CONCLUSIONS: Most soft-tissue wounds from Iraq and Afghanistan do not have significant bacterial burden upon arrival to and during initial treatment at NNMC. Improved evaluation of combat wound microbiology at all levels of care is warranted to determine shifts in microbiology and to impact care practices. PMID: 20887842 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | High cost of stage IV pressure ulcers. Am J Surg. 2010 Oct;200(4):473-7 Authors: Brem H, Maggi J, Nierman D, Rolnitzky L, Bell D, Rennert R, Golinko M, Yan A, Lyder C, Vladeck B BACKGROUND: The aim of this study was to calculate and analyze the cost of treatment for stage IV pressure ulcers. METHODS: A retrospective chart analysis of patients with stage IV pressure ulcers was conducted. Hospital records and treatment outcomes of these patients were followed up for a maximum of 29 months and analyzed. Costs directly related to the treatment of pressure ulcers and their associated complications were calculated. RESULTS: Nineteen patients with stage IV pressure ulcers (11 hospital-acquired and 8 community-acquired) were identified and their charts were reviewed. The average hospital treatment cost associated with stage IV pressure ulcers and related complications was $129,248 for hospital-acquired ulcers during 1 admission, and $124,327 for community-acquired ulcers over an average of 4 admissions. CONCLUSIONS: The costs incurred from stage IV pressure ulcers are much greater than previously estimated. Halting the progression of early stage pressure ulcers has the potential to eradicate enormous pain and suffering, save thousands of lives, and reduce health care expenditures by millions of dollars. PMID: 20887840 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Cells of the oligodendroglial lineage, myelination, and remyelination. Biochim Biophys Acta. 2010 Sep 28; Authors: Miron VE, Kuhlmann T, Antel JP Myelin is critical in maintaining electrical impulse conduction in the central nervous system. The oligodendrocyte is the cell type responsible for myelin production within this compartment. The mutual supply of trophic support between oligodendrocytes and the underlying axons may indicate why demyelinated axons undergo degeneration more readily; the latter contributes to the neural decline in multiple sclerosis (MS). Myelin repair, termed remyelination, occurs in acute inflammatory lesions in MS and is associated with functional recovery and clinical remittances. Animal models have demonstrated that remyelination is mediated by oligodendrocyte progenitor cells (OPCs) which have responded to chemotactic cues, migrated into the lesion, proliferated, differentiated into mature oligodendrocytes, and ensheathed demyelinated axons. The limited remyelination observed in more chronic MS lesions may reflect intrinsic properties of neural cells or extrinsic deterrents. Therapeutic strategies currently under development include transplantation of exogenous OPCs and promoting remyelination by endogenous OPCs. All currently approved MS therapies are aimed at dampening the immune response and are not directly targeting neural processes. PMID: 20887785 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Computational Fluid Dynamics Modeling Of Momentum Transport In Rotating Wall Perfused Bioreactor For Cartilage Tissue Engineering. J Biotechnol. 2010 Sep 28; Authors: Cinbiz MN, Tığlı RS, BeÅŸkardeÅŸ IG, GümüşderelioÄŸlu M, Colak U In this study, computational fluid dynamics (CFD) analysis of a rotating-wall perfused-vessel (RWPV) bioreactor is performed to characterize the complex hydrodynamic environment for the simulation of cartilage development in RWPV bioreactor in the presence of tissue-engineered cartilage constructs, i.e., cell-chitosan scaffolds. Shear stress exerted on chitosan scaffolds in bioreactor was calculated for different rotational velocities in the range of 33-38rpm. According to the calculations, the lateral and lower surfaces were exposed to 0.07926-0.11069 dyne/cm(2) and 0.05974-0.08345 dyne/cm(2), respectively, while upper surfaces of constructs were exposed to 0.09196-0.12847 dyne/cm(2). Results validate adequate hydrodynamic environment for scaffolds in RWPV bioreactor for cartilage tissue development which concludes the suitability of operational conditions of RWPV bioreactor. PMID: 20887759 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Novel approach by nanobiomaterials in vascular tissue engineering. Cell Transplant. 2010 Sep 30; Authors: Hung HS, Chen HC, Tsai CH, Lin SZ Interactions between vascular endothelial cells (EC) and biomaterials are important for engineered tissue substitute. The modification of biomaterial surfaces are designed to modulate EC adhesion and responses in order to improve implantation success rate. Specifically, it has now been well established that increased vascular tissue regeneration can be achieved on almost any surface by employing novel nano-fabricated surface features. To enhance EC adhesion and growth, material surface have been modified with physico-chemical and mechanical properties, such as bioactive molecules from the matrix, peptides and/or growth factors to control EC behavior. The advances in nanotechnology can bring additional functionality to vascular tissue engineering, optimize internal vascular graft surface, help to direct the differentiation of stem cells into the vascular cell phenotype, and most importantly, also provide a biomaterials-based cellularization process. Nanomaterials could promote in situ endothelialization by mobilizing endothelial progenitor cells (EPC) from the bone marrow, by encouraging cell-specific adhesion to the vascular graft and, once attached, by controlling the proliferation and differentiation of these cells. Interaction between different cell types and extracellular matrix continue to be a principal source of inspiration for material biological function and therefore, the understanding of the molecular mechanism trigger by the interaction is discussed. PMID: 20887685 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Vascular protection and restorative therapy in ischemic stroke. Cell Transplant. 2010 Sep 30; Authors: Yamashita T, Deguchi K, Nagotani S, Abe K Possible strategies for treating stroke include: 1) Thrombolytic therapy with tissue plasminogen activator (tPA): restoring cerebral blood flow in the acute phase of ischemic stroke but sometimes causing hemorrhagic transformation (HT); 2) Stem cell therapy: the repair of disrupted neuronal networks with newly born neurons in the chronic phase of ischemic stroke. Firstly, we estimated the vascular-protective effect of a free radical scavenger, edaravone, in the tPA-treated rat model of middle cerebral artery occlusion. Edaravone prevented dramatically decreased the hemorrhagic transformation and improved the neurologic score and survival rate of tPA-treated rats. Secondly, we attempted to restore brain tissue using a novel biomaterial, polydimethysiloxane-tetraethoxysilane (PDMS-TEOS) hybrid with or without vascular endothelial growth factor (VEGF), and we could show that implantation of a PDMS-TEOS scaffold with VEGF might be effective for treating old brain infarction or trauma. In the future, we will combine these strategies to develop more effective therapies for treatment of strokes. PMID: 20887680 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Functional Cells Cultured on Microcarriers for Use in Regenerative Medicine Research. Cell Transplant. 2010 Sep 30; Authors: Sun LY, Lin SZ, Li YS, Harn HJ, Chiou TW Microcarriers have been successfully used for many years for growing anchorage-dependent cells and as a means of delivering cells for tissue repair. When cultured on microcarriers, the number of anchorage-dependent cells, including primary cells, can easily be scaled up and controlled to generate the quantities of cells necessary for therapeutic applications. Recently, stem cell technology has been recognized as a powerful tool in regenerative medicine, but adequate numbers of stem cells that retain their differentiation potential are still difficult to obtain. For anchorage-dependent stem cells, however, microcarrier-based suspension culture using various types of microcarriers has proven to be a good alternative for effective ex vivo expansion. In this article, we review studies reporting the expansion, differentiation, or transplantation of functional anchorage-dependent cells that were expanded with the microcarrier culture system. Thus, the implementation of technological advances in biodegradable microcarriers, the bead-to-bead transfer process, and appropriate stem cell media may soon foster the ability to produce the numbers of stem cells necessary for cell-based therapies and/or tissue engineering. PMID: 20887678 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Botanical Drugs and Stem Cells. Cell Transplant. 2010 Sep 30; Authors: Chang PC, Liu PY, Lin SZ, Wu WC, Chen WS, Tsai CH, Chiou TW, Harn HJ The potential to generate virtually any differentiated cell type from stem cells offers the possibility of creating new sources of cells for regenerative medicine. To realize this potential, it will be essential to control stem cell differentiation. Chinese herbal medicine is a major aspect of traditional Chinese medicine and is a rich source of unique chemicals. As such, individual herbs or extracts may play a role in the proliferation and differentiation of stem cells. In this review, we discuss some of the Chinese herbal medicines that are used to treat human diseases such as neuronal degenerative diseases, cardiovascular diseases, and osteoporosis. We also describe the relationship between Chinese herbal medicines and stem cell regulation. PMID: 20887674 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Culture and in vitro hepatogenic differentiation of placenta-derived stem cells, using placental extract as an alternative to serum. Cell Prolif. 2010 Oct;43(5):435-44 Authors: Shin KS, Lee HJ, Jung J, Cha DH, Kim GJ Abstract Objectives:  Translational research using adult stem cells derived from various tissues has been highlighted in cell-based therapy. However, there are many limitations to using conventional culture systems of adult stem cells for clinically applicability, including limited combinations of cytokines and use of nutrients derived from animals. Here, we have investigated the effects of placental extract (PE) for culture of placenta-derived stem cells (PDSCs) as well as their potential for hepatogenic differentiation. Materials and methods:  Placental extract, extracted using water-soluble methods, was used as a supplement for culture of PDSCs. Cell viability was determined using the MTT assay, and cytokine assay was performed using Luminex assay kit. Gene expression, indocyanine green (ICG) up-take, PAS (Periodic Acid-Schiff) staining and urea production were also analysed. Results:  The placental extract contained several types of cytokine and chemokine essential for maintenance and differentiation of stem cells. Expression of stemness markers in PDSCs cultured with PE is no different from that of PDSCs cultured with foetal bovine serum (FBS). After hepatogenic differentiation, expression patterns for hepatocyte-specific markers in PDSCs cultured with PE were consistent and potential for hepatogenic differentiation of PDSCs cultured with PE was similar to that of PDSCs cultured with FBS, as shown by PAS staining and urea production assays. Conclusions:  Our findings revealed that placental extract could be used as a new component for culture of adult stem cells, as well as for development of human-based medium, in translational research for regenerative medicine. PMID: 20887550 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Differentiation of bone marrow-derived mesenchymal stem cells into hepatocyte-like cells in an alginate scaffold. Cell Prolif. 2010 Oct;43(5):427-34 Authors: Lin N, Lin J, Bo L, Weidong P, Chen S, Xu R Abstract Objectives:  Alginate scaffolds are the most frequently investigated biomaterials in tissue engineering. Tissue engineering techniques that generate liver tissue have become important for treatment of a number of liver diseases and recent studies indicate that bone marrow-derived stem cells (BMSCs) can differentiate into hepatocyte-like cells. The goal of the study described here, was to examine in vitro hepatic differentiation potential of BMSCs cultured in an alginate scaffold. Materials and methods:  To investigate the potential of BMSCs to differentiate into hepatocyte-like cells, we cultured BMSCs in alginate scaffolds in the presence of specific growth factors including hepatocyte growth factor, epidermal growth factor and fibroblast growth factor-4. Results:  We can demonstrate that alginate scaffolds are compatible for growth of BMSCs and when cultured in alginate scaffolds for several days they display several liver-specific markers and functions. Specifically, they expressed genes encoding alpha-foetoprotein, albumin (ALB), connexin 32 and CYP7A1. In addition, these BMSCs produced both ALB and urea, expressed cytokeratin-18 (CK-18) and were capable of glycogen storage. Percentage of CK-18 positive cells, a marker of hepatocytes, was 56.7%. Conclusions:  Our three-dimensional alginate scaffolds were highly biocompatible with BMSCs. Furthermore, culturing induced their differentiation into hepatocyte-like cells. Therefore, BMSCs cultured in alginate scaffolds may be applicable for hepatic tissue engineering. PMID: 20887549 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Sequence-based typing showed a novel HLA-DQB1*05 allele, DQB1*05:01:03. Tissue Antigens. 2010 Sep 30; Authors: Jakubauskas A, Griskevicius L The novel allele HLA-DQB1*05:01:03 differs from HLA-DQB1*05:01:01 by a silent nucleotide substitution at codon 77R (AGG to AGA). PMID: 20887386 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of Pore Architecture on Oxygen Diffusion in 3D Scaffolds for Tissue Engineering. J Biomech Eng. 2010 Oct;132(10):104506 Authors: Ahn G, Park JH, Kang T, Lee JW, Kang HW, Cho DW The aim of this study was to maximize oxygen diffusion within a three-dimensional scaffold in order to improve cell viability and proliferation. To evaluate the effect of pore architecture on oxygen diffusion, we designed a regular channel shape with uniform diameter, referred to as cylinder shaped, and a new channel shape with a channel diameter gradient, referred to as cone shaped. A numerical analysis predicted higher oxygen concentration in the cone-shaped channels than in the cylinder-shaped channels, throughout the scaffold. To confirm these numerical results, we examined cell proliferation and viability in 2D constructs and 3D scaffolds. Cell culture experiments revealed that cell proliferation and viability were superior in the constructs and scaffolds with cone-shaped channels. PMID: 20887024 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | 3D Cell Growth and Proliferation on a RGD Functionalized Nanofibrillar Hydrogel Based on a Conformationally Restricted Residue Containing Dipeptide. ACS Appl Mater Interfaces. 2010 Oct 1; Authors: Panda JJ, Dua R, Mishra A, Mittra B, Chauhan VS Three-dimensional (3D) hydrogels incorporating a compendium of bioactive molecules can allow efficient proliferation and differentiation of cells and can thus act as successful tissue engineering scaffolds. Self-assembled peptide-based hydrogels can be worthy candidates for such applications as peptides are biocompatible, biodegradable and can be easily functionalized with desired moieties. Here, we report 3D growth and proliferation of mammalian cells (HeLa and L929) on a dipeptide hydrogel chemically functionalized with a pentapeptide containing Arg-Gly-Asp (RGD) motif. The method of functionalization is simple, direct and can be adapted to other functional moieties as well. The functionalized gel was noncytotoxic, exhibited enhanced cell growth promoting properties, and promoted 3D growth and proliferation of cells for almost 2 weeks, with simultaneous preservation of their metabolic activities. The presence of effective cell growth supporting properties in a simple and easy to functionalize dipeptide hydrogel is unique and makes it a promising candidate for tissue engineering and cell biological applications. PMID: 20886861 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Activation of MKK3/6, SAPK, and ATF-2/c-jun in ACL fibroblasts grown in 3 dimension collagen gels in response to application of cyclic strain. J Orthop Res. 2010 Sep 30; Authors: Wright V, Attia E, Bohnert K, Brown H, Bhargava M, Hannafin JA Signal transduction pathways involved in response to cyclic tensile strain and strain deprivation in anterior cruciate ligament (ACL) fibroblasts grown in 3D collagen gels were investigated. Application of cyclic tensile strain resulted in significant activation (phosphorylation) of MKK3/6, SAPK and their downstream target transcription factors, ATF-2 and c-jun, while strain deprivation resulted in a decrease in these kinases and transcription factors. These data suggest that ACL fibroblasts cultured in 3D collagen gels respond to the mechanical environment and provide a useful system for determination of the molecular mechanisms involved in the regulation of proliferation and matrix turnover by mechanical load. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. PMID: 20886655 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Release Kinetics and in vitro Bioactivity of Basic Fibroblast Growth Factor: Effect of the Thickness of Fibrous Matrices. Macromol Biosci. 2010 Sep 30; Authors: Kim MS, Shin YM, Lee JH, Kim SI, Nam YS, Shin CS, Shin H In this study, we fabricated non-woven matrices using blends of polycaprolactone and gelatin with various spinning volumes to control the immobilized heparin content, which was ultimately intended to increase the immobilization efficiency of bFGF. The amount of bFGF on the heparin conjugated fibrous matrices depended on the thicknesses of the swollen matrices ranging from 35.4 ± 6.5 to 162.3 ± 14.0 ng and ≈90% of the bFGF was gradually released over a period of up to 56 d. The released bFGF enhanced the proliferation of human umbilical vein endothelial cells and human mesenchymal stem cells. In conclusion, our heparin-conjugated fibrous matrices have the potential to be used as a growth factor delivery system in tissue engineering applications. PMID: 20886548 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Abrogation of e-cadherin-mediated cellular aggregation allows proliferation of pluripotent mouse embryonic stem cells in shake flask bioreactors. PLoS One. 2010;5(9): Authors: Mohamet L, Lea ML, Ward CM BACKGROUND: A fundamental requirement for the exploitation of embryonic stem (ES) cells in regenerative medicine is the ability to reproducibly derive sufficient numbers of cells of a consistent quality in a cost-effective manner. However, undifferentiated ES cells are not ideally suited to suspension culture due to the formation of cellular aggregates, ultimately limiting scalability. Significant advances have been made in recent years in the culture of ES cells, including automated adherent culture and suspension microcarrier or embryoid body bioreactor culture. However, each of these methods exhibits specific disadvantages, such as high cost, additional downstream processes or reduced cell doubling times. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that abrogation of the cell surface protein E-cadherin, using either gene knockout (Ecad-/-) or the neutralising antibody DECMA-1 (EcadAb), allows culture of mouse ES cells as a near-single cell suspension in scalable shake flask culture over prolonged periods without additional media supplements. Both Ecad-/- and EcadAb ES cells exhibited adaptation phases in suspension culture, with optimal doubling times of 7.3 h±0.9 and 15.6 h±4.7 respectively and mean-fold increase in viable cell number of 95.1±2.0 and 16±0.9-fold over 48 h. EcadAb ES cells propagated as a dispersed cell suspension for 15 d maintained expression of pluripotent markers, exhibited a normal karyotype and high viability. Subsequent differentiation of EcadAb ES cells resulted in expression of transcripts and proteins associated with the three primary germ layers. CONCLUSIONS/SIGNIFICANCE: This is the first demonstration of the culture of pluripotent ES cells as a near-single cell suspension in a manual fed-batch shake flask bioreactor and represents a significant improvement on current ES cell culture techniques. Whilst this proof-of-principle method would be useful for the culture of human ES and iPS cells, further steps are necessary to increase cell viability of hES cells in suspension. PMID: 20886069 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Defining Hypo-Methylated Regions of Stem Cell-Specific Promoters in Human iPS Cells Derived from Extra-Embryonic Amnions and Lung Fibroblasts. PLoS One. 2010;5(9): Authors: Nishino K, Toyoda M, Yamazaki-Inoue M, Makino H, Fukawatase Y, Chikazawa E, Takahashi Y, Miyagawa Y, Okita H, Kiyokawa N, Akutsu H, Umezawa A BACKGROUND: Human induced pluripotent stem (iPS) cells are currently used as powerful resources in regenerative medicine. During very early developmental stages, DNA methylation decreases to an overall low level at the blastocyst stage, from which embryonic stem cells are derived.Therefore, pluripotent stem cells, such as ES and iPS cells, are considered to have hypo-methylated status compared to differentiated cells. However, epigenetic mechanisms of "stemness" remain unknown in iPS cells derived from extra-embryonic and embryonic cells. METHODOLOGY/PRINCIPAL FINDINGS: We examined genome-wide DNA methylation (24,949 CpG sites covering 1,3862 genes, mostly selected from promoter regions) with six human iPS cell lines derived from human amniotic cells and fetal lung fibroblasts as well as two human ES cell lines, and eight human differentiated cell lines using Illumina's Infinium HumanMethylation27. A considerable fraction (807 sites) exhibited a distinct difference in the methylation level between the iPS/ES cells and differentiated cells, with 87.6% hyper-methylation seen in iPS/ES cells. However, a limited fraction of CpG sites with hypo-methylation was found in promoters of genes encoding transcription factors. Thus, a group of genes becomes active through a decrease of methylation in their promoters. Twenty-three genes including SOX15, SALL4, TDGF1, PPP1R16B and SOX10 as well as POU5F1 were defined as genes with hypo-methylated SS-DMR (Stem cell-Specific Differentially Methylated Region) and highly expression in iPS/ES cells. CONCLUSIONS/SIGNIFICANCE: We show that DNA methylation profile of human amniotic iPS cells as well as fibroblast iPS cells, and defined the SS-DMRs. Knowledge of epigenetic information across iPS cells derived from different cell types can be used as a signature for "stemness" and may allow us to screen for optimum iPS/ES cells and to validate and monitor iPS/ES cell derivatives for human therapeutic applications. PMID: 20885964 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | A stem cell-based tool for small molecule screening in adipogenesis. PLoS One. 2010;5(9): Authors: Qin J, Li WQ, Zhang L, Chen F, Liang WH, Mao FF, Zhang XM, Lahn BT, Yu WH, Xiang AP Techniques for small molecule screening are widely used in biological mechanism study and drug discovery. Here, we reported a novel adipocyte differentiation assay for small molecule selection, based on human mesenchymal stem cells (hMSCs) transduced with fluorescence reporter gene driven by adipogenic specific promoter - adipocyte Protein 2 (aP2; also namely Fatty Acid Binding Protein 4, FABP4). During normal adipogenic induction as well as adipogenic inhibition by Ly294002, we confirmed that the intensity of green fluorescence protein corresponded well to the expression level of aP2 gene. Furthermore, this variation of green fluorescence protein intensity can be read simply through fluorescence spectrophotometer. By testing another two small molecules in adipogenesis -Troglitazone and CHIR99021, we proved that this is a simple and sensitive method, which could be applied in adipocyte biology, drug discovery and toxicological study in the future. PMID: 20885962 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Ciprofloxacin criteria in antimicrobial prophylaxis and bladder cancer recurrence. Med Sci Monit. 2010 Oct 1;16(10):RA218-223 Authors: Gurtowska N, Kloskowski T, Drewa T Oral ciprofloxacin might achieve higher concentration in urine than in serum; theoretically, this drug might act as an anticancer drug against bladder cancer cells. Among fluoroquinolones, ciprofloxacin is distinguished by strong inhibition of topoisomerase II. A good correlation between cytotoxic activity of ciprofloxacin toward eukaryotic cells and its ability to induce the cleavable complexes topoisomerase II-DNA has been demonstrated. These data provide a basis for supposing that ciprofloxacin may act as anticancer drug. The efforts of evaluating ciprofloxacin's influence on human bladder cell lines have been shown by many authors. The cells were exposed to ciprofloxacin at various concentrations that are attainable in the urine after oral drug administration. Antiproliferative potential of the ciprofloxacin against human bladder cells varies according to drug concentration and time of incubation. It seems that ciprofloxacin can act as an anticancer drug in eukaryotic cells. Low urine pH can enhance the antitumor effect of ciprofloxacin. Ciprofloxacin enhances the effect of action of doxorubicin and epirubicin, which are used to prevent bladder cancer recurrence after transurethral resection of superficial bladder cancer.<br /> We think that ciprofloxacin might be used for antibacterial prophylaxis and as an anticancer agent in patients with superficial bladder cancer. This idea must be checked in future placebo controlled trials. PMID: 20885364 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells have the potential to rejuvenate regenerative medicine research. Med Sci Monit. 2010 Oct 1;16(10):RA197-217 Authors: Eve DJ, Fillmore R, Borlongan CV, Sanberg PR The increasing number of publications featuring the use of stem cells in regenerative processes supports the idea that they are revolutionizing regenerative medicine research. In an analysis of the articles published in the journal Cell Transplantation - The Regenerative Medicine Journal between 2008 and 2009, which reveals the topics and categories that are on the cutting edge of regenerative medicine research, stem cells are becoming increasingly relevant as the "runner-up" category to "neuroscience" related articles. The high volume of stem cell research casts a bright light on the hope for stem cells and their role in regenerative medicine as a number of reports deal with research using stem cells entering, or seeking approval for, clinical trials.<br /> The "methods and new technologies" and "tissue engineering" sections were almost equally as popular, and in part, reflect attempts to maximize the potential of stem cells and other treatments for the repair of damaged tissue. Transplantation studies were again more popular than non-transplantation, and the contribution of stem cell-related transplants was greater than other types of transplants. The non-transplantation articles were predominantly related to new methods for the preparation, isolation and manipulation of materials for transplant by specific culture media, gene therapy, medicines, dietary supplements, and co-culturing with other cells and further elucidation of disease mechanisms. A sizeable proportion of the transplantation articles reported on how previously new methods may have aided the ability of the cells or tissue to exert beneficial effects following transplantation.<br /> PMID: 20885363 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Scarless fetal wound healing: a basic science review. Plast Reconstr Surg. 2010 Oct;126(4):1172-80 Authors: Larson BJ, Longaker MT, Lorenz HP SUMMARY:: Scar formation is a major medical problem that can have devastating consequences for patients. The adverse physiological and psychological effects of scars are broad, and there are currently no reliable treatments to prevent scarring. In contrast to adult wounds, early gestation fetal skin wounds repair rapidly and in the absence of scar formation. Despite extensive investigation, the exact mechanisms of scarless fetal wound healing remain largely unknown. For some time, it has been known that significant differences exist among the extracellular matrix, inflammatory response, cellular mediators, and gene expression profiles of fetal and postnatal wounds. These differences may have important implications in scarless wound repair. PMID: 20885241 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Intrinsics and dynamics of fat grafts: an in vitro study. Plast Reconstr Surg. 2010 Oct;126(4):1155-62 Authors: Stillaert FB, Abberton KM, Keramidaris E, Thompson EW, Blondeel PN, Morrison WA BACKGROUND:: Despite a revived interest in fat grafting procedures, clinicians still fail to demonstrate clearly the in vivo behavior of fat grafts as a dynamic tissue substitute. However, the basic principles in cellular biology teach us that cells can survive and develop, provided that a structural matrix exists that directs their behavior. The purpose of this in vitro study was to analyze that behavior of crude fat grafts, cultured on a three-dimensional laminin-rich matrix. METHODS:: Nonprocessed, human fat biopsy specimens (approximately 1 mm) were inoculated on Matrigel-coated wells to which culture medium was added. The control group consisted of fat biopsy specimens embedded in medium alone. The cellular proliferation pattern was followed over 6 weeks. Additional cultures of primary generated cellular spheroids were performed and eventually subjected to adipogenic differentiation media. RESULTS:: A progressive outgrowth of fibroblast-like cells from the core fat biopsy specimen was observed in both groups. Within the Matrigel group, an interconnecting three-dimensional network of spindle-shaped cells was established. This new cell colony reproduced spheroids that functioned again as solitary sources of cellular proliferation. Addition of differentiation media resulted in lipid droplet deposition in the majority of generated cells, indicating the initial steps of adipogenic differentiation. CONCLUSIONS:: The authors noticed that crude, nonprocessed fat biopsy specimens do have considerable potential for future tissue engineering-based applications, provided that the basic principles of developmental, cellular biology are respected. Spontaneous in vitro expansion of the stromal cells present in fat grafts within autologous and injectable matrices could create "off-the-shelf" therapies for reconstructive procedures. PMID: 20885240 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The use of fibrin glue in surgery of the knee. J Bone Joint Surg Br. 2010 Oct;92(10):1325-31 Authors: Patel S, Rodriguez-Merchan EC, Haddad FS Fibrin glue, also known as fibrin sealant, is now established as a haemostatic agent in surgery, but its role in orthopaedic surgery is neither well known nor clearly defined. Although it was originally used over 100 years ago, concerns about transmission of disease meant that it fell from favour. It is also available as a slow-release drug delivery system and as a substrate for cellular growth and tissue engineering. Consequently, it has the potential to be used in a number of ways in orthopaedic surgery. The purpose of this review is to address its use in surgery of the knee in which it appears to offer great promise. PMID: 20884966 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Epicardium-derived cells: a new source of regenerative capacity. Heart. 2010 Sep 30; Authors: Vieira JM, Riley PR Cardiovascular regenerative medicine aims to counter muscle loss post ischaemic disease with the identification of new cellular sources for cardiomyocyte replacement. A number of embryonic and adult cell models have been explored preclinically and in patient trials, but modest outcome, coupled with issues with impaired graft survival and limited/immature (trans-) differentiation alongside host rejection, has left the door open for more therapeutically efficacious sources of myocardial regeneration. Due to its fundamental role in heart development, the epicardium emerges as an obvious candidate. Here, recent findings are reviewed that show adult epicardium-derived cells as a new source of regenerative capacity for heart repair. PMID: 20884787 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell therapy doctor struck off by the GMC. BMJ. 2010;341:c5410 Authors: Dyer C PMID: 20884707 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Regulation of Valvular Interstitial Cell Phenotype and Function by Hyaluronic Acid in 2-D and 3-D Culture Environments. Matrix Biol. 2010 Sep 24; Authors: Rodriguez KJ, Piechura LM, Masters KS Disruption of the extracellular matrix (ECM) is frequently found in calcific aortic valve disease (CAVD), yet the role of ECM components in valvular interstitial cell (VIC) function and dysfunction remains poorly understood. This study examines the contributions of exogenous and endogenous hyaluronic acid (HA), in both two-dimensional (2D) and 3D environments, in regulating the phenotype and calcification of VICs. VIC calcification was first assessed in a 2D setting in which the cells were exposed to different molecular weights of exogenous HA presented in either an immobilized or soluble form. Delivery of HA suppressed nodule formation in a molecular weight-dependent manner, while blocking VIC recognition of HA via an antibody to CD44 abolished these nodule-suppressive effects and stimulated other hallmarks of valvular dysfunction. These 2D results were then validated in a more physiologically-relevant setting, using an approach that allowed the characterization of VIC phenotype in response to HA alterations in the native 3D environment. In this approach, leaflet organ cultures were analyzed following treatment with anti-CD44 or with hyaluronidase to specifically remove HA. Disruption of VIC-HA interactions upregulated markers of VIC disease and induced leaflet mineralization. Similarly, HA-deficient leaflets exhibited numerous hallmarks of CAVD, including increased VIC proliferation, apoptosis, increased expression of disease-related markers, and mineralization. These findings suggest that VIC-HA interactions are crucial in maintaining a healthy VIC phenotype. Identification of ECM components that can regulate VIC phenotype and function has significant implications for understanding of native valve disease, investigating possible treatments, and designing new biomaterials for valve tissue engineering. PMID: 20884350 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Investigation of Mechanical Properties and Porosity Relationships in Selective Laser -Sintered Polyhedral for Functionally Graded Scaffolds. Acta Biomater. 2010 Sep 27; Authors: Sudarmadji N, Tan JY, Leong KF, Chua CK, Loh YT An important requirement for a bone tissue engineering scaffold is to have a stiffness gradient that mimics that of a native bone. Such scaffolds can be achieved by controlling their structure and porosity and are regarded as functionally graded scaffolds (FGS). Currently, the main challenges in FGS fabrication include the iterative and tedious design process as well as heavy reliance on a user's CAD/CAM skills. This work aims to bring a step closer towards automated FGS production by providing a database that correlates scaffold porosity values and their corresponding compressive stiffness and integrating it into the design process. To achieve this goal, scaffolds with different structural configurations were designed using CASTS (Computer Aided System for Tissue Scaffolds), an in-house developed library system consisting of 13 different polyhedral units that can be assembled into scaffold structures. Polycaprolactone (PCL) was chosen as the scaffold material, while selective laser sintering, a powder-based rapid prototyping (RP) or additive manufacturing (AM) system, was employed to fabricate the scaffolds. Mathematical relations correlating scaffold porosity and compressive stiffness readings were formulated and compiled. In addition, cytotoxicity assessment was conducted to evaluate the toxicity of the fabricated PCL scaffolds. Lastly, a brief demonstration on how the formulated relations are used in the FGS design process is presented. PMID: 20883840 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Thermosensitive polymeric matrices for three-dimensional cell culturing strategies. Acta Biomater. 2010 Sep 27; Authors: Duarte AR, Mano JF, Reis RL A completely new strategy for cell culturing focused on the design of 3D smart surfaces by supercritical fluid technology was developed. This approach might overcome the limitations in cell expansion and proliferation of the currently existing techniques. An alternative technology, based on supercritical carbon dioxide was used to polymerize PNIPAAm and to foam P(D,L)LA, creating therefore a thermosensitive 3D structure which has proven to have potential as substrate for cell growth and expansion. We demonstrated that the thermosensitive matrices promoted the cell detachment, thus P(D,L)LA scaffolds have the potential to be used as substrates for cell growth and expansions avoiding enzymatic and mechanic methods of cell harvesting. The harvest cells were replated to evaluate their viability, which was not compromised. A major advantage of this technology is the fact that the materials prepared can be recovered and reused. Therefore, the same substrate can be recycled and reused for different batches. An indirect impact of the technology developed is related with biotechnology field as this novel technology for cell expansion can be applied for any adherent cell cultures. PMID: 20883833 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Involvement of oxidative stress in simvastatin-induced apoptosis of murine CT26 colon carcinoma cells. Toxicol Lett. 2010 Sep 27; Authors: Qi XF, Kim DH, Yoon YS, Cai DQ, Shim KY, Lee KJ Recent studies have suggested that oxidative stress may play a role in the cytotoxic activity of statins against cancer cells. The objective of this study was to elucidate the role of oxidative stress in the cytotoxicity of simvastatin in murine CT26 colon carcinoma cells and B16BL6 melanoma cells. We found that CT26 cells were more sensitive to simvastatin than B16BL16 cells. Interestingly, exposure to simvastatin causes significant apoptotic cell death and perturbations in parameters indicative of oxidative stress in CT26 cells. Moreover, the increase in oxidative stress parameters and cell death were suppressed by isoprenoids including mevalonolactone, farnesyl pyrophosphate ammonium salt, geranylgeranyl pyrophosphate ammonium salt, and coenzyme Q10, and by antioxidants including N-acetyl cysteine, reduced glutathione, superoxide dismutases (SOD), and catalase (CAT) alone or in combination, but were promoted by an inhibitor of glutathione synthesis, L-buthionine-sulfoximine. The signaling pathway induced by simvastatin breaks down the antioxidant defense system by suppressing the expression of reactive oxygen species scavengers, particularly Mn-SOD, CAT, GPx1, and SESN 3, thereby inducing oxidative stress and apoptotic cell death. Collectively, our results demonstrate that simvastatin induces colon cancer cell death at least in part by increasing intracellular oxidative stress and inducing apoptosis. PMID: 20883752 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Loss of solute carriers in T cell-mediated rejection in mouse and human kidneys: an active epithelial injury-repair response. Am J Transplant. 2010 Oct;10(10):2241-51 Authors: Einecke G, Kayser D, Vanslambrouck JM, Sis B, Reeve J, Mengel M, Famulski KS, Bailey CG, Rasko JE, Halloran PF T cell-mediated rejection of kidney allografts causes epithelial deterioration, manifested by tubulitis, but the mechanism remains unclear. We hypothesized that interstitial inflammation triggers a stereotyped epithelial response similar to that triggered by other types of injury such as ischemia-reperfusion. We identified solute carrier transcripts with decreased expression in mouse allografts, and compared their behavior in T cell-mediated rejection to native kidneys with ischemic acute tubular necrosis (ATN). Average loss of solute carrier expression was similar in ATN (77%) and T cell-mediated rejection (75%) with high correlation of individual transcripts. Immunostaining of SLC6A19 confirmed loss of proteins. Analysis of human kidney transplant biopsies confirmed that T cell-mediated rejection and ATN showed similar loss of solute carrier mRNAs. The loss of solute carrier expression was weakly correlated with interstitial inflammation, but kidneys with ATN showed decreased solute carriers despite minimal inflammation. Loss of renal function correlated better with decreased solute carrier expression than with histologic lesions (r = 0.396, p < 0.001). Thus the loss of epithelial transcripts in rejection is not a unique consequence of T cell-mediated rejection but an active injury-repair response of epithelium, triggered by rejection but also by other injury mechanisms. PMID: 20883558 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | ORIGINAL ARTICLE: Cutaneous Malassezia microbiota of healthy subjects differ by sex, body part and season. J Dermatol. 2010 Sep;37(9):786-92 Authors: Akaza N, Akamatsu H, Sasaki Y, Takeoka S, Kishi M, Mizutani H, Sano A, Hirokawa K, Nakata S, Matsunaga K Malassezia is a component of normal cutaneous resident microbiota. The aim of this study was to quantitatively clarify the differences in cutaneous Malassezia microbiota in healthy subjects by sex, body part and season. Samples were collected from the forehead, cheek, upper chest and upper back of 20 healthy men and 20 healthy women (average age 32 years) in summer and winter by the swab method. Malassezia DNA was analyzed using a real-time PCR system. As a result, in sex, body parts and season, men, the upper trunk and summer showed the highest total numbers of cutaneous Malassezia species on average. There were also differences depending on the analytical method. The predominant species were M. restricta on the face of men, M. globosa and M. dermatis on the upper trunk of men, and M. globosa and M. sympodialis on the upper trunk of women. This study clarified that the cutaneous Malassezia microbiota of healthy subjects differed by sex, body part and season. PMID: 20883362 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Intracelluar release of 17-β estradiol from cationic polyamidoamine dendrimer surface modified poly lactic-co-glycolic acid microparticles improves osteogenic differentiation of human mesenchymal stromal cells. Tissue Eng Part C Methods. 2010 Sep 30; Authors: Hong L, Krishnamachari Y, Seabold D, Joshi VB, Schneider G, Salem AK Human bone marrow mesenchymal stromal cells (MSCs) are considered a potential cell source for MSC-based bone regeneration, but improvements in the proliferation and differentiation capacity of MSCs are necessary for practical applications. Estrogen effectively improves MSC capabilities and has strong potential as a regulator of MSCs. The aim of this study was to develop a delivery system that provides intracellular release of estrogen and test its ability to improve osteogenic differentiation of MSCs. Biodegradable poly (lactic-co-glycolic acid) (PLGA) microparticles were developed that entrap 17-β estradiol (E2) and provide intracellular release of E2. The results show that we can prepare PLGA particles with efficient loading of E2 and maintain release of E2 up to 7 days. Surface modifying E2-loaded PLGA particles with cationic PAMAM dendrimers enabled increased uptake by human MSCs. Human MSC uptake of the E2 loaded PLGA particles significantly up regulates osteogenic differentiation markers of ALP and osteocalcin. In conclusion, cationic modified PLGA particles can serve as a tool for intracellular delivery of estrogen to effectively execute estrogen regulation of MSCs. This approach has the potential to improve the osteogenic capabilities of MSCs and to develop appropriate environments of implantation for MSC-based bone tissue engineering. PMID: 20883116 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The potential of stem cells in adult tissues representative of the three germ layers. Tissue Eng Part A. 2010 Sep 30; Authors: Obokata H, Kojima K, Westerman K, Yamato M, Okano T, Tsuneda S, Vacanti CA Mature adult tissues contain stem cells that express many genes normally associated with the early stage of embryonic development, when maintained in appropriate environments. Cells procured from adult tissues representative the three germ layers (spinal cord, muscle, and lung), each exhibit the potential to mature into cells representative of all three germ layers. Cells isolated from adult tissues of different germ layer origin, were propagated as non-adherent clusters or spheres that were composed of heterogeneous populations of cells. When the clusters or spheres were dissociated, the cells had the ability to reform new, non-adherent spheres for several generations. When implanted in vivo, in association with biodegradable scaffolds, into immunodeficient mice, tissue containing cells characteristic of the three germ layers was generated. These findings suggest the existence of a population of stem cells in adult tissues that is quite different and distinct from embryonic stem cells (ESCs), that demonstrate a greater potency for differentiation across germ lines than previously believed. Such cells could potentially be as useful as ESCs in tissue engineering and regenerative medicine. PMID: 20883115 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stromal cell-derived factor-1alpha activation of tissue-engineered endothelial progenitor cell matrix enhances ventricular function after myocardial infarction by inducing neovasculogenesis. Circulation. 2010 Sep 14;122(11 Suppl):S107-17 Authors: Frederick JR, Fitzpatrick JR, McCormick RC, Harris DA, Kim AY, Muenzer JR, Marotta N, Smith MJ, Cohen JE, Hiesinger W, Atluri P, Woo YJ BACKGROUND: Myocardial ischemia causes cardiomyocyte death, adverse ventricular remodeling, and ventricular dysfunction. Endothelial progenitor cells (EPCs) have been shown to ameliorate this process, particularly when activated with stromal cell-derived factor-1α (SDF), known to be the most potent EPC chemokine. We hypothesized that implantation of a tissue-engineered extracellular matrix (ECM) scaffold seeded with EPCs primed with SDF could induce borderzone neovasculogenesis, prevent adverse geometric remodeling, and preserve ventricular function after myocardial infarction. METHODS AND RESULTS: Lewis rats (n=82) underwent left anterior descending artery ligation to induce myocardial infarction. EPCs were isolated, characterized, and cultured on a vitronectin/collagen scaffold and primed with SDF to generate the activated EPC matrix (EPCM). EPCM was sutured to the anterolateral left ventricular wall, which included the region of ischemia. Control animals received sutures but no EPCM. Additional groups underwent application of the ECM alone, ECM primed with SDF (ECM+SDF), and ECM seeded with EPCs but not primed with SDF (ECM+SDF). At 4 weeks, borderzone myocardial tissue demonstrated increased levels of vascular endothelial growth factor in the EPCM group. When compared to controls, Vessel density as assessed by immunohistochemical microscopy was significantly increased in the EPCM group (4.1 versus 6.2 vessels/high-powered field; P<0.001), and microvascular perfusion measured by lectin microangiography was enhanced 4-fold (0.7% versus 2.7% vessel volume/section volume; P=0.04). Comparisons to additional groups also showed a significantly improved vasculogenic response in the EPCM group. Ventricular geometry and scar fraction assessed by digital planimetric analysis of sectioned hearts exhibited significantly preserved left ventricular internal diameter (9.7 mm versus 8.6 mm; P=0.005) and decreased infarct scar formation expressed as percent of total section area (16% versus 7%; P=0.002) when compared with all other groups. In addition, EPCM animals showed a significant preservation of function as measured by echocardiography, pressure-volume conductance, and Doppler flow. CONCLUSIONS: Extracellular matrix seeded with EPCs primed with SDF induces borderzone neovasculogenesis, attenuates adverse ventricular remodeling, and preserves ventricular function after myocardial infarction. PMID: 20837901 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Pyramidal neurons are generated from oligodendroglial progenitor cells in adult piriform cortex. J Neurosci. 2010 Sep 8;30(36):12036-49 Authors: Guo F, Maeda Y, Ma J, Xu J, Horiuchi M, Miers L, Vaccarino F, Pleasure D Previous studies have shown that oligodendroglial progenitor cells (OPCs) can give rise to neurons in vitro and in perinatal cerebral cortex in vivo. We now report that OPCs in adult murine piriform cortex express low levels of doublecortin, a marker for migratory and immature neurons. Additionally, these OPCs express Sox2, a neural stem cell marker, and Pax6, a transcription factor characteristic of progenitors for cortical glutamatergic neurons. Genetic fate-mapping by means of an inducible Cre-LoxP recombination system proved that these OPCs differentiate into pyramidal glutamatergic neurons in piriform cortex. Several lines of evidence indicated that these newly formed neurons became functionally integrated into the cortical neuronal network. Our data suggest that NG2(+)/PDGFRα(+) proteolipid protein promoter-expressing progenitors generate pyramidal glutamatergic neurons within normal adult piriform cortex. PMID: 20826667 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Discussion: Adipose tissue-derived stem cells enhance bioprosthetic mesh repair of ventral hernias. Plast Reconstr Surg. 2010 Sep;126(3):855-7 Authors: Dumanian GA PMID: 20811218 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Depot-specific variation in the osteogenic and adipogenic potential of human adipose-derived stromal cells. Plast Reconstr Surg. 2010 Sep;126(3):822-34 Authors: Levi B, James AW, Glotzbach JP, Wan DC, Commons GW, Longaker MT BACKGROUND: Adipose-derived stromal cells hold promise for use in tissue regeneration. However, multiple facets of their biology remain unclear. The authors examined the variations in osteogenesis and adipogenesis in adipose-derived stromal cells between subcutaneous fat depots and potential molecular causes. METHODS: Adipose-derived stromal cells were isolated from human patients from subcutaneous fat depots, including arm, flank, thigh, and abdomen (n = 5 patients). Osteogenic and adipogenic differentiation was performed (alkaline phosphatase, alizarin red, and oil red O staining, and quantitative real-time polymerase chain reaction). Co-cultures were established to assess the paracrine effect of human adipose-derived stromal cells on mouse osteoblasts. Finally, HOX gene expression was analyzed by quantitative real-time polymerase chain reaction. RESULTS: Subcutaneous fat depots retain markedly different osteogenic and adipogenic potentials. Osteogenesis was most robust in adipose-derived stromal cells from the flank and thigh, as compared with those from the arm and abdomen (p < 0.05 by all markers examined). This was accompanied by elevations of BMP4 and BMPR1B (p < 0.05 by all markers examined). The osteogenic advantage of cells from the flank and thigh was again observed when analyzing the paracrine effects of these cells. Conversely, those cells isolated from the flank had a lesser ability to undergo adipogenic differentiation. Adipose-associated HOX genes were less expressed in flank-derived adipose-derived stromal cells. CONCLUSIONS: Variations exist between fat depots in terms of adipose-derived stromal cell osteogenic and adipogenic differentiation. Differences in HOX expression and bone morphogenetic protein signaling may underlie these observations. This study indicates that the choice of fat depot derivation of adipose-derived stromal cells may be an important one for future efforts in tissue engineering. PMID: 20811215 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Paracrine interaction between adipose-derived stromal cells and cranial suture-derived mesenchymal cells. Plast Reconstr Surg. 2010 Sep;126(3):806-21 Authors: James AW, Levi B, Commons GW, Glotzbach J, Longaker MT BACKGROUND: Adipose-derived stromal cells are a potential cell source for the successful healing of skeletal defects. In this study, the authors sought to investigate the potential for cranial suture-derived mesenchymal cells to promote the osteogenic differentiation of adipose-derived stromal cells. Various reports have previously examined the unique in vitro attributes of suture-derived mesenchymal cells; this study sought to extend those findings. METHODS: Suture-derived mesenchymal cells were isolated from wild-type mice (n = 30) from both fusing posterofrontal and patent sagittal sutures. Cells were placed in Transwell inserts with human adipose-derived stromal cells (n = 5 patients) with osteogenic differentiation medium with or without recombinant Noggin (10 to 400 ng/ml). Specific gene expression of osteogenic markers and Hedgehog pathway were assayed; standard osteogenic assays (alkaline phosphatase and alizarin red staining) were performed. All assays were performed in triplicate. RESULTS: Both posterofrontal and sagittal suture-derived mesenchymal cells induced osteogenic differentiation of adipose-derived stromal cells (p < 0.05). Posterofrontal suture-derived mesenchymal cells induced adipose-derived stromal cell osteogenesis to a greater degree than sagittal suture-derived mesenchymal cells (p < 0.05). This was accompanied by an increase in bone morphogenetic protein expression (p < 0.05). Finally, recombinant Noggin mitigated the pro-osteogenic effects of co-culture accompanied by a reduction in Hedgehog signaling (p < 0.05). CONCLUSIONS: Suture-derived mesenchymal cells secrete paracrine factors that induce osteogenic differentiation of multipotent stromal cells (human adipose-derived stromal cells). Cells derived from the fusing posterofrontal suture do this to a significantly greater degree than cells from the patent sagittal suture. Enhanced bone morphogenetic protein and Hedgehog signaling may underlie this paracrine effect. PMID: 20811214 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Visual enhancement of laparoscopic partial nephrectomy with 3-charge coupled device camera: assessing intraoperative tissue perfusion and vascular anatomy by visible hemoglobin spectral response. J Urol. 2010 Oct;184(4):1279-85 Authors: Crane NJ, Gillern SM, Tajkarimi K, Levin IW, Pinto PA, Elster EA PURPOSE: We report the novel use of 3-charge coupled device camera technology to infer tissue oxygenation. The technique can aid surgeons to reliably differentiate vascular structures and noninvasively assess laparoscopic intraoperative changes in renal tissue perfusion during and after warm ischemia. MATERIALS AND METHODS: We analyzed select digital video images from 10 laparoscopic partial nephrectomies for their individual 3-charge coupled device response. We enhanced surgical images by subtracting the red charge coupled device response from the blue response and overlaying the calculated image on the original image. Mean intensity values for regions of interest were compared and used to differentiate arterial and venous vasculature, and ischemic and nonischemic renal parenchyma. RESULTS: The 3-charge coupled device enhanced images clearly delineated the vessels in all cases. Arteries were indicated by an intense red color while veins were shown in blue. Differences in mean region of interest intensity values for arteries and veins were statistically significant (p >0.0001). Three-charge coupled device analysis of pre-clamp and post-clamp renal images revealed visible, dramatic color enhancement for ischemic vs nonischemic kidneys. Differences in the mean region of interest intensity values were also significant (p <0.05). CONCLUSIONS: We present a simple use of conventional 3-charge coupled device camera technology in a way that may provide urological surgeons with the ability to reliably distinguish vascular structures during hilar dissection, and detect and monitor changes in renal tissue perfusion during and after warm ischemia. PMID: 20723937 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Load measurement accuracy from sensate scaffolds with and without a cartilage surface. J Invest Surg. 2010 Jun;23(3):156-62 Authors: Geffre CP, Finkbone PR, Bliss CL, Margolis DS, Szivek JA ABSTRACT The use of "sensate" scaffolds covered with tissue-engineered cartilage has emerged as a possible treatment option for focal articular cartilage defects. The ability to monitor joint loading provides several benefits that can be useful in both clinical and research situations. Previous studies have shown that these scaffolds can accurately monitor in vivo joint loading during various activities. However, the effect that an articular cartilage layer or soft tissue overgrowth has on scaffold sensitivity has not been tested. Eight scaffolds were tested with cartilage samples taken from four hounds. Three strain gauges were attached to each scaffold and a servo hydraulics system was used to test sensitivity while the scaffold was in contact with cartilage, metal, or silicone surfaces. Strain gauge sensitivity was calculated from load and strain measurements collected during testing. There was no significant difference between the mean strain gauge sensitivities when the scaffolds were in contact with the different surfaces: cartilage 30.9 +/- 16.2 muepsilon/N, metal 31.8 +/- 18.6 muepsilon/N, and silicone 30.6 +/- 12.3 muepsilon/N. These results indicate that "sensate" scaffolds can be calibrated and used to monitor load with the presence of an articular cartilage layer. PMID: 20590387 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of negative fixed-charge density in tissue-engineered cartilage by quantitative MRI and relationship with biomechanical properties. J Biomech Eng. 2010 Jul;132(7):071014 Authors: Miyata S, Homma K, Numano T, Tateishi T, Ushida T Applying tissue-engineered cartilage in a clinical setting requires noninvasive evaluation to detect the maturity of the cartilage. Magnetic resonance imaging (MRI) of articular cartilage has been widely accepted and applied clinically in recent years. In this study, we evaluated the negative fixed-charge density (nFCD) of tissue-engineered cartilage using gadolinium-enhanced MRI and determined the relationship between nFCD and biomechanical properties. To reconstruct cartilage tissue, articular chondrocytes from bovine humeral heads were embedded in agarose gel and cultured in vitro for up to 4 weeks. The nFCD of the cartilage was determined using the MRI gadolinium exclusion method. The equilibrium modulus was determined using a compressive stress relaxation test, and the dynamic modulus was determined by a dynamic compression test. The equilibrium compressive modulus and dynamic modulus of the tissue-engineered cartilage increased with an increase in culture time. The nFCD value--as determined with the [Gd-DTPA(2-)] measurement using the MRI technique--increased with culture time. In the regression analysis, nFCD showed significant correlations with equilibrium compressive modulus and dynamic modulus. From these results, gadolinium-enhanced MRI measurements can serve as a useful predictor of the biomechanical properties of tissue-engineered cartilage. PMID: 20590292 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Anti-VEGF effects of intravitreal erythropoietin in early diabetic retinopathy. Front Biosci (Elite Ed). 2010;2:912-27 Authors: Zhang J, Hu LM, Xu G, Wu Y, Shen J, Luo Y, Zhong Y, Sinclair SH, Yanoff M, Li W, Xu GT In the present study, a single intravitreal erythropoietin (EPO) to diabetic rats produced therapeutic effects on blood-retinal barrier (BRB) function and neuronal survival at different time courses of retinopathy. In parallel, the hypoxia-inducible factor 1 alpha (HIF-1 alpha) pathway has been quantitatively studied, including VEGF-A, endogenous EPO, EPO receptor (EpoR), prolyl hydroxylases (PHD1-3) and von Hippel-Lindau tumor suppressor (VHL). The mRNA levels of HIF-1 alpha, VEGF-A, endogenous EPO, PHD1-3 and VHL are all up-regulated in the diabetic retina, and suppressed by exogenous EPO. The increased protein levels of HIF-1 alpha, VEGF-A, and endogenous EPO found in diabetic retinas also have been down-regulated by exogenous EPO. The results demonstrate that the HIF-1 pathway is activated in the retina in early diabetes, but is negatively regulated by a feedback loop following the administration of exogenous EPO. Exogenous EPO at pharmacologic levels leads to suppression of VEGF and in turn, restoration of the normal functions of BRB in a time-dependent manner. In the diabetic retina, the same level of exogenous EPO that inhibits VEGF also exerted neuronal protection. PMID: 20515763 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo and in vitro laser confocal microscopy to diagnose acanthamoeba keratitis. Cornea. 2010 Aug;29(8):861-5 Authors: Shiraishi A, Uno T, Oka N, Hara Y, Yamaguchi M, Ohashi Y PURPOSE: To determine the effectiveness of laser confocal microscopy in identifying Acanthamoeba cysts and trophozoites in the cornea of patients with Acanthamoeba keratitis (AK) and to evaluate its effectiveness in following AK after treatment. METHODS: The corneas of 9 patients clinically diagnosed with AK were monitored periodically with the Heidelberg Retina Tomograph II-Rostock Cornea Module (HRT II-RCM) to examine for Acanthamoeba cysts and trophozoites during the clinical course. RESULTS: Seven of 9 patients had positive corneal smears, and 5 of 9 patients had positive laboratory cultures. HRT II-RCM demonstrated the presence of highly reflective polygonal shadows with lower reflective borders in the cornea of all patients. In 1 patient, a highly reflective pleomorphic shadow with small less-reflective areas was detected inside the cell. The former finding resembled the image of Acanthamoeba cysts in culture as observed by HRT II-RCM, and the latter observation with that of Acanthamoeba trophozoites in culture. After treatment, the number of highly reflective inflammatory cells decreased and the number and morphology of the corneal epithelial cells with highly reflective nuclei recovered to normal levels. CONCLUSION: These results indicate that in vivo laser confocal microscopy can be a useful method to make a diagnosis and to follow patients with AK. PMID: 20508505 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Design and characterization of a modified T-flask bioreactor for continuous monitoring of engineered tissue stiffness. Biotechnol Prog. 2010 May-Jun;26(3):857-64 Authors: Lasher RA, Wolchok JC, Parikh MK, Kennedy JP, Hitchcock RW Controlling environmental conditions, such as mechanical stimuli, is critical for directing cells into functional tissue. This study reports on the development of a bioreactor capable of controlling the mechanical environment and continuously measuring force-displacement in engineered tissue. The bioreactor was built from off the shelf components, modified off the shelf components, and easily reproducible custom built parts to facilitate ease of setup, reproducibility and experimental flexibility. A T-flask was modified to allow for four tissue samples, mechanical actuation via a LabView controlled stepper motor and transduction of force from inside the T-flask to an external sensor. In vitro bench top testing with instrumentation springs and tissue culture experiments were performed to validate system performance. Force sensors were highly linear (R(2) > 0.998) and able to maintain force readings for extended periods of time. Tissue culture experiments involved cyclic loading of polyurethane scaffolds seeded with and without (control) human foreskin fibroblasts for 8 h/day for 14 days. After supplementation with TGF-beta, tissue constructs showed an increase in stiffness between consecutive days and from the acellular controls. These experiments confirmed the ability of the bioreactor to distinguish experimental groups and monitor tissue stiffness during tissue development. PMID: 20187075 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
No comments:
Post a Comment