|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Human adipose tissue-derived stem cells exhibit proliferation potential and spontaneous rhythmic contraction after fusion with neonatal rat cardiomyocytes. FASEB J. 2010 Nov 8; Authors: Metzele R, Alt C, Bai X, Yan Y, Zhang Z, Pan Z, Coleman M, Vykoukal J, Song YH, Alt E Various types of stem cells have been shown to have beneficial effects on cardiac function. It is still debated whether fusion of injected stem cells with local resident cardiomyocytes is one of the mechanisms. To better understand the role of fusion in stem cell-based myocardial regeneration, the present study was designed to investigate the fate of human adipose tissue-derived stem cells (hASCs) fused with neonatal rat cardiomyocytes in vitro. hASCs labeled with the green fluorescent probe Vybrant DiO were cocultured with neonatal rat cardiomyocytes labeled with the red fluorescent probe Vybrant DiI and then treated with fusion-inducing hemagglutinating virus of Japan (HVJ). Cells that incorporated both red and green fluorescent signals were considered to be hASCs that had fused with rat cardiomyocytes. Fusion efficiency was 19.86 ± 4.84% at 5 d after treatment with HVJ. Most fused cells displayed cardiomyocyte-like morphology and exhibited spontaneous rhythmic contraction. Both immunofluorescence staining and lentiviral vector labeling showed that fused cells contained separate rat cardiomyocyte and hASC nuclei. Immunofluorescence staining assays demonstrated that human nuclei in fused cells still expressed the proliferation marker Ki67. In addition, hASCs fused with rat cardiomyocytes were positive for troponin I. Whole-cell voltage-clamp analysis demonstrated action potentials in beating fused cells. RT-PCR analysis using rat- or human-specific myosin heavy chain primers revealed that the myosin heavy-chain expression in fused cells was derived from rat cardiomyocytes. Real-time PCR identified expression of human troponin T in fused cells and the presence of rat cardiomyocytes induced a cardiomyogenic protein expression of troponin T in human ASCs. This study illustrates that hASCs exhibit both stem cell (proliferation) and cardiomyocyte properties (action potential and spontaneous rhythmic beating) after fusion with rat cardiomyocytes, supporting the theory that fusion, even if artificially induced in our study, could indeed be a mechanism for cardiomyocyte renewal in the heart.-Metzele, R., Alt, C., Bai, X., Yan, Y., Zhang, Z., Pan, Z., Coleman, M., Vykoukal, J., Song, Y.-H., Alt, E. Human adipose tissue-derived stem cells exhibit proliferation potential and spontaneous rhythmic contraction after fusion with neonatal rat cardiomyocytes. PMID: 21059751 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human placenta-derived mesenchymal stem cells and islet-like cell clusters generated from these cells as a novel source for stem cell therapy in diabetes. Rev Diabet Stud. 2010;7(2):168-82 Authors: Kadam S, Muthyala S, Nair P, Bhonde R Placental tissue holds great promise as a source of cells for regenerative medicine due to its plasticity, and easy availability. Human placenta-derived mesenchymal stem cells (hPDMSCs) have the potential to differentiate into insulin-producing cells. Upon transplantation, they can reverse experimental diabetes in mice. However, it is not known whether culture-expanded undifferentiated hPDMSCs are capable of restoring normoglycemia upon transplantation in streptozotocin (STZ)-induced diabetic mice. Hence we prepared long-term cultures of hPDMSCs from the chorionic villi of full-term human placenta. Flow cytometry analyses and immunocytochemistry study revealed bonafide mesenchymal nature of the isolated hPDMSCs. These cultures could differentiate into adipogenic, oesteogenic, chondrogenic, and neuronal lineages on exposure to lineage-specific cocktails. Furthermore, we showed that hPDMSCs can form islet-like cell clusters (ILCs) on stepwise exposure to serum-free defined media containing specific growth factors and differentiating agents. qRT-PCR showed the expression of insulin, glucagon, and somatostatin in undifferentiated hPDMSCs and in ILCs. Differentiated ILCs were found to express human insulin, glucagon, and somatostatin by immunocytochemistry. Additionally, ILCs also showed abundance of pancreatic transcription factors ngn3 and isl1. Both undifferentiated hPDMSCs and ILCs exihibited insulin secretion in response to glucose. Transplantation of hPDMSCs or ILCs derived from hPDMSCs in STZ-induced diabetic mice led to restoration of normoglycemia. Our results demonstrate, for the first time, reversal of hyperglycemia by undifferentiated hPDMSCs and ILCs derived from hPDMSCs. These results suggest human placenta-derived MSCs as an alternative source for cell replacement therapy in diabetes. PMID: 21060975 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Turning human epidermis into pancreatic endoderm. Rev Diabet Stud. 2010;7(2):158-67 Authors: Santamaria P, Rodriguez-Piza I, Clemente-Casares X, Yamanouchi J, Mulero-Perez L, Aasen T, Raya A, Izpisua Belmonte JC OBJECTIVE: Human embryonic stem (hES) cells can be differentiated into pancreatic endoderm structures in vitro. The study was performed to determine whether induced pluripotent stem (iPS) cells can be differentiated into similar structures with comparable efficiency. METHODS: We compared the ability of hES cells and iPS cells derived from human epidermal keratinocytes to progressively differentiate into pancreatic endoderm. Human foreskin keratinocytes were reprogrammed to pluripotency by transduction with retroviruses encoding Oct4, Sox2, and Klf4. The resulting keratinocyte-derived iPS (KiPS) cell lines and a hES cell line were subjected to a modified pancreatic endoderm differentiation protocol. Cells and embryoid-body structures derived from both hES and KiPS cells were compared at different stages of development for expression of stem cell and differentiation markers, including Sox2, Oct4, Mixl1, Brachyury, Gsc, FoxA2, Sox17, Hnf4α, Hnf1β, Nkx2.2, Nkx6.1, Hex, Isl1, Pdx1, and Slc2A, via Taqman real-time PCR, flow-cytometry, and/or immunocytochemistry. RESULTS: hES cells and KiPS cells expressed similar levels of the stem cell factors Sox2 and Oct4. Upon differentiation, both cell types underwent remarkably similar changes in gene expression. They acquired the definitive endoderm markers Sox17 and FoxA2. Most Sox17+ and FoxA2+ cells co-expressed Hnf4α and Hnf1β, found in the primitive gut tube, a pancreas precursor. Most FoxA2+ cells were also Pdx1+, and many expressed Nkx2.2, Nkx6.1, and Isl1. CONCLUSIONS: Keratinocyte-derived iPS cells can be differentiated into pancreatic endoderm, and the efficiency of this process is comparable to that seen for hES cells. Thus keratinocytes have the potential to serve as a source of patient-specific pancreatic endoderm for transplantation. PMID: 21060974 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | GTP Cyclohydrolase I/BH4 Pathway Protects EPCs via Suppressing Oxidative Stress and Thrombospondin-1 in Salt-Sensitive Hypertension. Hypertension. 2010 Nov 8; Authors: Xie HH, Zhou S, Chen DD, Channon KM, Su DF, Chen AF Endothelial progenitor cells (EPCs) are both reduced and dysfunctional in hypertension that correlates inversely with its mortality, but the mechanisms are poorly understood. Endothelial nitric oxide synthase (eNOS) critically regulates EPC mobilization and function but is uncoupled in salt-sensitive hypertension because of the reduced cofactor tetrahydrobiopterin (BH4). We tested the hypothesis that GTP cyclohydrolase I (GTPCH I), the rate-limiting enzyme of BH4 de novo synthesis, protects EPCs and its function in deoxycorticosterone acetate (DOCA)-salt mice. EPCs were isolated from peripheral blood and bone marrow of wild-type (WT), WT DOCA-salt, endothelial-specific GTPCH transgenic (Tg-GCH), GTPCH transgenic DOCA-salt, and BH4-deficient hph-1 mice. In WT DOCA-salt and hph-1 mice, EPCs were significantly decreased with impaired angiogenesis and adhesion, which were restored in Tg-GCH DOCA-salt mice. Superoxide (O2(-)) and nitric oxide (NO) levels in EPCs were elevated and reduced, respectively, in WT DOCA-salt and hph-1 mice; both were rescued in Tg-GCH DOCA-salt mice. eNOS(-/-)/GCH(+/-) hybrid mice demonstrated that GTPCH preserved the circulating EPC number, reduced intracellular O2(-) in EPCs, and ameliorated EPC dysfunction independent of eNOS in DOCA-salt hypertension. Secreted thrombospondin-1 (TSP-1; a potent angiogenesis inhibitor) from EPCs was elevated in WT DOCA-salt and hph-1 but not DOCA-salt Tg-GCH mice. In vitro treatment with BH4, polyethylene glycol-superoxide dismutase (PEG-SOD), or Nomega-nitro-L-arginine (L-NNA) significantly augmented NO and reduced TSP-1 and O2(-) levels from EPCs of WT DOCA-salt mice. These results demonstrated, for the first time, that the GTPCH/BH4 pathway critically regulates EPC number and function in DOCA-salt hypertensive mice, at least in part, via suppressing TSP-1 expression and oxidative stress. PMID: 21059996 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Induced pluripotent stem cells: epigenetic memories and practical implications. Mol Hum Reprod. 2010 Nov 8; Authors: Sullivan GJ, Bai YM, Fletcher J, Wilmut I Induced pluripotent stem cells (iPSCs) may be obtained by direct reprogramming of different somatic cells to a pluripotent state by forced expression of a handful of transcription factors. It was generally assumed that iPSCs are functionally equivalent to their embryonic stem cell (ESC) counterparts. Recently, a number of research groups have demonstrated that this is not the case, showing that iPSCs retain 'epigenetic memory' of the donor tissue from which they were derived and display skewed differentiation potential. This raises the question whether such cells are fit for experimental, diagnostic or therapeutic purpose? A brief survey of the literature illustrates that differences at both epigenetic and transcriptome level are observed between various pluripotent stem cell populations. Interestingly, iPSC populations with perceived 'anomalies' can be coaxed to a more ESC-like cellular state either by continuous passaging - which attenuates these epigenetic differences - or treatment with small molecules that target the machinery responsible for remodeling the genome. This suggests that the establishment of an epigenetic status approximating an ESC counterpart is largely a passive process. The mechanisms responsible remain to be established. Meanwhile, other areas of reprogramming are rapidly evolving such as, trans-differentiation of one somatic cell type to another by the forced expression of key transcription factors. When it comes to assessing their practical usefulness, the same question will also apply. PMID: 21059705 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | SIRT2 down-regulation in HeLa can induce p53 accumulation via p38 MAPK activation-dependent p300 decrease, eventually leading to apoptosis. Genes Cells. 2010 Nov 9; Authors: Li Y, Matsumori H, Nakayama Y, Osaki M, Kojima H, Kurimasa A, Ito H, Mori S, Katoh M, Oshimura M, Inoue T We previously reported that sirtuin 2 (SIRT2), a mammalian member of the NAD+-dependent protein deacetylases, participates in mitotic regulation, specifically, in efficient mitotic cell death caused by the spindle checkpoint. Here, we describe a novel function of SIRT2 that is different from mitotic regulation. SIRT2 down-regulation using siRNA caused apoptosis in cancer cell lines such as HeLa cells, but not in normal cells. The apoptosis was caused by p53 accumulation, which is mediated by p38 MAPK activation-dependent degradation of p300 and the subsequent MDM2 degradation. Sirtuin inhibitors are emerging as antitumor drugs, and this function has been ascribed to the inhibition of SIRT1, the most well-characterized sirtuin that deacetylases p53 to promote cell survival and also binds to other proteins in response to genotoxic stress. This study suggests that SIRT2 can be a novel molecular target for cancer therapy and provides a molecular basis for the efficacy of SIRT2 for future cancer therapy. PMID: 21059157 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Efficient Generation of Nonhuman Primate iPS Cells. Stem Cells Dev. 2010 Nov 8; Authors: Zhong B, Trobridge GD, Zhang X, Watts K, Ramakrishnan A, Wohlfahrt M, Adair JE, Kiem HP Induced pluripotent stem (iPS) cells have great potential for regenerative medicine and gene therapy. Thus far, iPS cells have typically been generated using integrating viral vectors expressing various reprogramming transcription factors; nonintegrating methods have been less effective and efficient. Because there is a significant risk of malignant transformation and cancer involved with the use of iPS cells, careful evaluation of transplanted iPS cells will be necessary in small and large animal studies prior to clinical applications. Here, we have generated and characterized nonhuman primate iPS cells towards evaluating iPS cell transplantation in a clinically relevant large animal model. We developed stable Phoenix RD114-based packaging cell lines that produce <i>OCT4, SOX2, c-MYC</i> and <i>KLF4 (OSCK)</i> expressing gammaretroviral vectors. Using these vectors in combination with small molecules we were able to efficiently and reproducibly generate nonhuman primate iPS cells from pigtailed macaques (Macaca nemestrina). The established nonhuman primate iPS cells exhibited pluripotency and extensive self-renewal capacity. The facile and reproducible generation of nonhuman primate iPS cells using defined producer cells for the individual reprogramming factors should provide an important resource to optimize and evaluate iPS cell technology for studies involving stem cell biology and regenerative medicine. PMID: 21058905 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Early Increase in Myocardial Perfusion After Stem Cell Therapy in Patients Undergoing Incomplete Coronary Artery Bypass Surgery. J Cardiovasc Transl Res. 2010 Nov 9; Authors: Gowdak LH, Schettert IT, Rochitte CE, Lisboa LA, Dallan LA, César LA, de Oliveira SA, Krieger JE Incomplete revascularization is associated with worse long-term outcomes. Autologous bone marrow cells (BMC) have recently been tested in patients with severe coronary artery disease. We tested the hypothesis that intramyocardial injection of autologous BMC increases myocardial perfusion in patients undergoing incomplete coronary artery bypass grafting (CABG). Twenty-one patients (19 men), 59 ± 7 years old, with limiting angina and multivessel coronary artery disease (CAD), not amenable to complete CABG were enrolled. BMC were obtained prior to surgery, and the lymphomonocytic fraction separated by density gradient centrifugation. During surgery, 5 mL containing 2.1 ± 1.3 × 10(8) BMC (CD34+ = 0.8 ± 0.3%) were injected in the ischemic non-revascularized myocardium. Myocardial perfusion was assessed by magnetic resonance imaging (MRI) at baseline and 1 month after surgery. The increase in myocardial perfusion was compared between patients with <50% (group A, n = 11) with that of patients with >50% (group B, n = 10) of target vessels (stenosis ≥ 70%) successfully bypassed. Injected myocardial segments included the inferior (n = 12), anterior (n = 7), and lateral (n = 2) walls. The number of treated vessels (2.3 ± 0.8) was significantly smaller than the number of target vessels (4.2 ± 1.0; P < 0.0001). One month after surgery, cardiac MRI showed a similar reduction (%) in the ischemic score of patients in group A (72.5 ± 3.2), compared to patients in group B (78.1 ± 3.2; P = .80). Intramyocardial injection of autologous BMC may help increase myocardial perfusion in patients undergoing incomplete CABG, even in those with fewer target vessels successfully treated. This strategy may be an adjunctive therapy for patients suffering from a more advanced (diffuse) CAD not amenable for complete direct revascularization. PMID: 21061106 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human placenta-derived mesenchymal stem cells and islet-like cell clusters generated from these cells as a novel source for stem cell therapy in diabetes. Rev Diabet Stud. 2010;7(2):168-82 Authors: Kadam S, Muthyala S, Nair P, Bhonde R Placental tissue holds great promise as a source of cells for regenerative medicine due to its plasticity, and easy availability. Human placenta-derived mesenchymal stem cells (hPDMSCs) have the potential to differentiate into insulin-producing cells. Upon transplantation, they can reverse experimental diabetes in mice. However, it is not known whether culture-expanded undifferentiated hPDMSCs are capable of restoring normoglycemia upon transplantation in streptozotocin (STZ)-induced diabetic mice. Hence we prepared long-term cultures of hPDMSCs from the chorionic villi of full-term human placenta. Flow cytometry analyses and immunocytochemistry study revealed bonafide mesenchymal nature of the isolated hPDMSCs. These cultures could differentiate into adipogenic, oesteogenic, chondrogenic, and neuronal lineages on exposure to lineage-specific cocktails. Furthermore, we showed that hPDMSCs can form islet-like cell clusters (ILCs) on stepwise exposure to serum-free defined media containing specific growth factors and differentiating agents. qRT-PCR showed the expression of insulin, glucagon, and somatostatin in undifferentiated hPDMSCs and in ILCs. Differentiated ILCs were found to express human insulin, glucagon, and somatostatin by immunocytochemistry. Additionally, ILCs also showed abundance of pancreatic transcription factors ngn3 and isl1. Both undifferentiated hPDMSCs and ILCs exihibited insulin secretion in response to glucose. Transplantation of hPDMSCs or ILCs derived from hPDMSCs in STZ-induced diabetic mice led to restoration of normoglycemia. Our results demonstrate, for the first time, reversal of hyperglycemia by undifferentiated hPDMSCs and ILCs derived from hPDMSCs. These results suggest human placenta-derived MSCs as an alternative source for cell replacement therapy in diabetes. PMID: 21060975 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Prospects of Stem Cell Therapy in Diabetes - Introduction to the RDS Special Issue. Rev Diabet Stud. 2010;7(2):80-1 Authors: Efrat S PMID: 21060966 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Electrospray deposited fibronectin retains the ability to promote cell adhesion. J Biomed Mater Res B Appl Biomater. 2010 Nov 8; Authors: Martyn SV, Heywood HK, Rockett P, Paine MD, Wang MJ, Dobson PJ, Sheard SJ, Lee DA, Stark JP Scaffolds for tissue engineering require the correct biochemical cues if the seeded cells are to migrate into the scaffold and proliferate. For complex tissues this would require precise patterning of the scaffold structure with the particular biochemical cue required at each location on the scaffold. Electrospray enables the deposition of a wide number of biomolecules onto surfaces and can be used for precise patterning. We assessed the functionality of a key cell-adhesion molecule, fibronectin, after depositing it onto a surface using the electrospray technique. The addition of polypropylene glycol allowed a stable spray to be obtained from solutions with a range of fibronectin concentrations. Immunoassay tests showed that the amount of fibronectin retained on the surface was proportional to that sprayed from the solution. Increasing the surface density of fibronectin deposited onto silicon surfaces enhanced fibroblast attachment. The fibronectin thus appears to have retained its cell attachment functionality after undergoing the electrospray process. Since recent advances allow electrospray to pattern material from solution with micrometre accuracy this may allow materials to be biologically functionalized on a similar scale. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2010. PMID: 21061362 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The influence of type-I collagen-coated PLLA aligned nanofibers on growth of blood outgrowth endothelial cells. Biomed Mater. 2010 Nov 9;5(6):065011 Authors: Feng ZQ, Lu HJ, Leach MK, Huang NP, Wang YC, Liu CJ, Gu ZZ Nanofibrous scaffolds have been applied widely in tissue engineering to simulate the nanostructure of natural extracellular matrix (ECM) and promote cell bioactivity. The aim of this study was to design a biocompatible nanofibrous scaffold for blood outgrowth endothelial cells (BOECs) and investigate the interaction between the topography of the nanofibrous scaffold and cell growth. Poly(l-lactic acid) (PLLA) random and aligned nanofibers with a uniform diameter distribution were fabricated by electrospinning. NH(3) plasma etching was used to create a hydrophilic surface on the nanofibers to improve type-I collagen adsorption; the conditions of the NH(3) plasma etching were optimized by XPS and water contact angle analysis. Cell attachment, proliferation, viability, phenotype and morphology of BOECs cultured on type-I collagen-coated PLLA film (col-Film), random fibers (col-RFs) and aligned fibers (col-AFs) were detected over a 7 day culture period. The results showed that collagen-coated PLLA nanofibers improved cell attachment and proliferation; col-AFs induced the directional growth of cells along the aligned nanofibers and enhanced endothelialization. We suggest that col-AFs may be a potential implantable scaffold for vascular tissue engineering. PMID: 21060144 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fibronectin coating of collagen modules increases in vivo HUVEC survival and vessel formation in SCID mice. Acta Biomater. 2010 Nov 5; Authors: Cooper TP, Sefton MV Modular tissue engineering is a novel approach to creating scalable, self-assembling, three-dimensional tissue constructs with inherent vascularisation. Under initial methods, the subcutaneous implantation of human umbilical vein endothelial cell (HUVEC)-covered collagen modules in immunocompromised mice resulted in significant host inflammation and limited HUVEC survival. A minimally-invasive injection technique was used to minimize surgery-related inflammation, and cell death was attributed to extensive apoptosis within 72 hours of implantation. Coating collagen modules with fibronectin (Fn) was shown in vivo to reduce short-term HUVEC TUNEL staining by nearly 40%, while increasing long-term HUVEC survival by 30% to 45%, relative to collagen modules without fibronectin. Consequently, a 100% increase in the number of HUVEC-lined vessels was observed with Fn-coated modules, as compared to collagen-only modules, at 7 and 14 days post-implantation. Furthermore, vessels appeared to be perfused with host erythrocytes by day 7, and vessel maturation and stabilization was evident by day 14. PMID: 21059413 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Silk fibroin as a vehicle for drug delivery applications. J Control Release. 2010 Nov 5; Authors: Wenk E, Merkle HP, Meinel L Silk fibroin (SF), a naturally occurring protein polymer, has several unique properties making it a favorable matrix for the incorporation and delivery of a range of therapeutic agents. SF is biocompatible, slowly biodegradable, and endowed with excellent mechanical properties and processability. Novel manufacturing techniques including mild all-aqueous processes have expanded its range of application even to sensitive protein and nucleic acid therapeutics. SF matrices were demonstrated to successfully deliver protein drugs and preserve their potency. Adjustments in SF crystallinity, concentration and structure, the design of the delivery systems as well as the molecular weight and structure of the embedded agents represent important variables when it comes to precisely tailor the release kinetics of SF matrices. Other strategies to fine-tune the release from SF matrices comprise the embedment of drug loaded micro- or nanoparticles or the coating of micro- or nanoparticles with SF films. So far, the main focus of SF drug delivery systems has been on tissue regeneration applications. For instance, growth factor loaded SF scaffolds were suggested for the tissue engineering of bone and cartilage, as well as for vascular and nerve regeneration devices and wound healing products. Moreover, SF matrices were proposed for oral, transmucosal and ocular drug delivery. This article reviews SF properties and fabrication processes that affect the release from SF drug delivery systems. For illustration, we discuss a variety of examples for the incorporation of drugs into SF systems and their release. PMID: 21059377 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Decellularized matrices for tissue engineering. Expert Opin Biol Ther. 2010 Dec;10(12):1717-28 Authors: Hoshiba T, Lu H, Kawazoe N, Chen G Importance of the field: Biomimetic scaffolds and substrates of extracellular matrices (ECMs) play an important role in the regulation of cell function and in the guidance of new tissue regeneration, as an ECM has the intrinsic cues necessary to communicate with and dictate to cells. Areas covered in this review: This paper reviews the latest developments in ECM scaffolds and substrates obtained from decellularized tissues, organs or cultured cells and their application in tissue engineering. The ECM composition, structure, interaction with surrounding cells, preparation method and usage in the regeneration of various tissues and organs are summarised. What the reader will gain: The advantages and challenges of decellularized matrices are highlighted. Take home message: Similarity in the composition, microstructure and biomechanical properties of the decellularized scaffolds and substrates to those of the native tissues and organs maximizes the promotion effect in the regeneration of both structural and functional tissues and organs. Simple tissues as well as complicated organs have been decellularized and decellularization methods have been optimized to completely remove the cellular components while keeping the ECM intact. PMID: 21058932 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Complete Recombinant Silk-Elastinlike Protein-Based Tissue Scaffold. Biomacromolecules. 2010 Nov 8; Authors: Qiu W, Huang Y, Teng W, Cohn CM, Cappello J, Wu X Due to their improved biocompatibility and specificity over synthetic materials, protein-based biomaterials, either derived from natural sources or genetically engineered, have been widely fabricated into nanofibrous scaffolds for tissue engineering applications. However, their inferior mechanical properties often require the reinforcement of protein-based tissue scaffolds using synthetic polymers. In this study, we report the electrospinning of a completely recombinant silk-elastinlike protein-based tissue scaffold with excellent mechanical properties and biocompatibility. In particular, SELP-47K containing tandemly repeated polypeptide sequences derived from native silk and elastin was electrospun into nanofibrous scaffolds, and stabilized via chemical vapor treatment and mechanical preconditioning. When fully hydrated in 1× PBS at 37 °C, mechanically preconditioned SELP-47K scaffolds displayed elastic moduli of 3.4-13.2 MPa, ultimate tensile strengths of 5.7-13.5 MPa, deformabilities of 100-130% strain, and resilience of 80.6-86.9%, closely matching or exceeding those of protein-synthetic blend polymeric scaffolds. Additionally, SELP-47K nanofibrous scaffolds promoted cell attachment and growth, demonstrating their in vitro biocompatibility. PMID: 21058633 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | New players enter field of regenerative medicine. Manag Care. 2010 Sep;19(9):48-9 Authors: Morrow T PMID: 20931895 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Biocompatibility of plasma enhanced chemical vapor deposited poly(2-hydroxyethyl methacrylate) films for biomimetic replication of the intestinal basement membrane. Biomacromolecules. 2010 Jun 14;11(6):1579-84 Authors: Pfluger CA, Burkey DD, Wang L, Sun B, Ziemer KS, Carrier RL It is recognized that topographical features such as ridges and grooves can dramatically influence cell phenotype, motivating the development of substrates with precisely biomimetic topography for study of the influence on cultured cells. Intestinal basement membrane topography has been precisely replicated using plasma enhanced chemical vapor deposition (CVD) of poly(2-hydroxyethyl methacrylate) (pHEMA) on native tissue. The ability for CVD pHEMA to coat and retain the complex architecture of the intestinal basement membrane at the micrometer scale was demonstrated using electron microscopy and surface chemical analysis (XPS). The suitability of CVD pHEMA as a cell culture substrate was assessed. Caco-2 cells maintained a high (>85%) viability on CVD pHEMA. Cell attachment and proliferation on CVD pHEMA were similar to those observed on materials traditionally used for cell culture and microfabrication purposes. Results indicate that CVD pHEMA is useful for development of precise (micrometer-scale) topographically biomimetic substrates for cell culture. PMID: 20441140 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Oral malodorous compound activates mitochondrial pathway inducing apoptosis in human gingival fibroblasts. Clin Oral Investig. 2010 Aug;14(4):367-73 Authors: Fujimura M, Calenic B, Yaegaki K, Murata T, Ii H, Imai T, Sato T, Izumi Y Hydrogen sulfide (H(2)S) is a main cause of physiologic halitosis. H(2)S induces apoptosis in human gingival cells, which may play an important role in periodontal pathology. Recently, it has been reported that H(2)S induced apoptosis and DNA damage in human gingival fibroblasts (HGFs) by increasing the levels of reactive oxygen species. However, the mechanisms of H(2)S-induced apoptosis have not been clarified in HGFs. The objective of this study was to determine the apoptotic pathway activated by H(2)S in HGFs. The HGFs were exposed to 50 ng/mL H(2)S, resulting in 18 ng/mL in the culture medium, which is lower than the concentration in periodontal pockets. The number of apoptotic cells after 24 and 48 h incubation was significantly higher than that in the control cultures (p < 0.05). Mitochondrial membrane depolarization and the release of cytochrome c, and caspase-3, and caspase-9 were also significantly increased after both 24- and 48-h incubation (p < 0.05), whereas caspase-8, a key enzyme in the receptor ligand-mediated pathway causing apoptosis, was not activated. The present study shows that H(2)S triggered the mitochondrial pathway causing apoptosis in HGFs but did not activate the receptor ligand-mediated pathway. PMID: 19548012 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [Repairing rabbit orbital defects with human BMP-2 gene modified bone marrow stromal cells and coral]. Zhonghua Yan Ke Za Zhi. 2009 Jan;45(1):66-72 Authors: Fan XQ, Xiao CW, Zhou HF, Bi XP, Shi WD OBJECTIVE: To investigate the efficacy of tissue-engineered bone (human BMP-2 genetic modified BMSC combined with coral) in healing the segmental orbital defect in rabbits. METHODS: Rabbit BMSC were isolated and cultured in vitro, and cells of passage 2 were infected with adenovirus-mediated transfection of human BMP-2 gene (150 pfu/cell). After infection, the expression of BMP-2 was determined by RT-PCR and Western blot analysis, and cell proliferation and osteogenic differentiation were observed by flow cytometry, ALP and Alizarin red staining. A 12 mm bone defect in the infraorbital rim was induced by surgery in both orbits of 24 New Zealand white rabbits. The defects were repaired with modified tissue-engineered bone constructed with coral plus BMP-2 transfected BMSC (Group A, n = 12), constructed by coral plus non-transfected BMSC (Group B, n = 12) and grafts of coral alone (Group C, n = 12), with untreated group (Group D, n = 12) served as control. The osteogenesis of bone defect was monitored by gross observation, micro-CT measurement, histological and histomorphologic analysis at 4, 8, and 16 weeks after the implantation. RESULTS: After transfection, the BMP-2 expression was confirmed by RT-PCR and western blot, and the osteogenesis activity of BMSC could be obviously enhanced. The 12 mm segmental defect of rabbit orbit couldn't heal alone. Gross observation and micro-CT demonstrated well the bony-union in experimental group, with higher bone mineral density and more bone volume than other control groups (F = ll.46, F = 7180.97; P < 0.05). CONCLUSION: This study demonstrated that the rabbit orbital defect could be successfully repaired by tissue-engineered bone constructed with human BMP-2 gene modified BMSC and coral. PMID: 19484934 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [Biocompatibility of acellular corneal stroma and transplantation of tissue-engineered corneal epithelium]. Zhonghua Yan Ke Za Zhi. 2008 Oct;44(10):934-42 Authors: Fang XF, Zhao J, Shi WY, Xie LX OBJECTIVE: To evaluate the biocompatibility of xenogeneic acellular corneal stroma, the feasibility of tissue engineered corneal epithelial transplantation, and verify the long term survival of epithelial allograft. METHODS: It was a experimental study. Porcine corneal stroma was treated by dispase followed by Triton-X-100 detergent. Treated porcine corneal stroma (group A) or fresh corneal stroma (group B) were put into the sac of rabbit cornea. Rabbit cornea without implantation of porcine corneal stroma was used as the control group (group C). Immunological rejection was evaluated in morphology, histopathology and immunohistochemistry in month 1, 3, 6. Female rabbit underwent lamellar keratoplasty (LK) using male tissue engineered corneal epithelium as donors, and immunological rejection after LK was analyzed. The corneas were collected at day 1, 3, 7, 15 and 30 after LK and evaluated by histopathology, immunohistochemistry and sex-determining region of Y-chromosome (SRY)-PCR analysis. RESULTS: All corneas became transparent gradually after the transplantation of treated porcine corneal stroma and were not rejected. The epithelium, stroma, endothelium, Bowman's and Descemet's membrane were preserved in all corneas of group A and B in histological observations, collagen fibers were parallel, a few keratocytes presented in the acellular and fresh corneal stromas. The corneas of group C were normal in histological sections. No significant immune rejection was noted in any of the corneas. The corneas in the study of transplantation of tissue engineered cornea epithelium recovered smoothly in 3 or 4 days, turned transparent in 15 or 20 days after surgery and were not stained by fluorescein. Well-differentiated corneal epithelium were recognized at 15 and 30 days after LK. Many keratocytes infiltrated into the scaffold. SRY-PCR analysis showed that allogenic donor corneal epithelium cells could survive in recipients after a long-term observation. CONCLUSIONS: Acellular porcine corneal stroma shows a satisfying biocompatibility. Tissue engineered corneal epithelium using acellular porcine corneal stroma as carrier could be used as donors for LK with satisfactory results. Donor cells have the potential to survive in recipients after long-term observation. PMID: 19176124 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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