|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | The prospects for new sales of California state bonds – the only source of funding for the $3 billion California stem cell agency – remain dim, according to an article today in Bond Buyer.
"The California bond market has become hamstrung by the delay" in coming up with a prudent state budget in Sacramento, wrote Randall Jensen in the public finance newspaper.
Jensen(no relation to this writer | | | | | | | | | | | | | | | | | | | | | | | | | Two recent items have vanished from this blog because of worldwide problems with the hosting service, Blogger, which is part of Google's operations. Blogger says it is attempting to restore the items, which have disappeared from all of its thousands of blogs. If not, we will restore them later. Thanks for your patience. | | | | | | | | | | | | | | | | | | | | | | | | | Hematopoietic stem/progenitor cells express functional mitochondrial energy-dependent cystic fibrosis transmembrane conductance regulator. Stem Cells Dev. 2011 May 11; Authors: Piro D, Piccoli C, Guerra L, Sassone F, D'Aprile A, Favia M, Castellani S, Di Gioia S, Lepore S, Garavaglia ML, Trotta T, Maffione AB, Casavola V, Meyer G, Capitanio N, Conese M Bone marrow-derived hematopoietic stem/progenitor cells (HSPCs) encompass a wide array of cell subsets with different capacities of engraftment and injured tissue regenerating potential. The characterization/isolation of the stem cell subpopulations represents a major challenge to improve the efficacy of transplantation protocols used in regenerative medicine. Cystic fibrosis (CF) is one of the diseases whose hope of cure relies on the successful application of cell-based gene therapy. This study was aimed at characterizing murine HSPCs on the basis of their bioenergetic competence and CFTR expression. Positively immunoselected Sca-1+ HSPCs encompassed two populations distinguished by their different size, Sca-1 expression and mitochondrial content. The smaller were the cells the higher was Sca-1 expression and the lower was the intracellular density of functional mitochondria. RT-PCR and western blotting revealed that HSPCs expressed CFTR mRNA and protein, which was also functional, as assessed by spectrofluorimetric and patch-clamp techniques. Inhibition of mitochondrial oxidative phosphorylation by oligomycin resulted in a 70% decrease of both the intracelluar ATP content and CFTR-mediated channel activity. Finally, HSPCs with lower Sca-1 expression and higher mitochondrial content displayed higher CFTR levels. Our findings identify two subpopulations in HSPCs and unveil a so-far unappreciated relationship between bioenergetic metabolism and CFTR in HSPC biology. PMID: 21561312 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Transcriptional profiling of "guided bone regeneration" in a critical-size calvarial defect. Clin Oral Implants Res. 2011 Apr;22(4):382-9 Authors: Ivanovski S, Hamlet S, Retzepi M, Wall I, Donos N Objectives: Guided bone regeneration (GBR) is a commonly utilized surgical technique in the craniofacial region. The transcriptional mechanisms associated with this type of bone regeneration are not well understood. The aim of this study was to characterize the transcriptome associated with GBR of a critical-size calvarial defect in the rat. Material and methods: Critical-size calvarial defects were created in six Wistar strain rats and treated according to the principles of GBR. The tissue filling the regenerating defect was harvested at 7 and 14 days. Total RNA was extracted and microarray analysis was carried out to identify the differences in the transcriptome between days 7 and 14. Results: Gene ontology (GO) analysis of the genes up-regulated at day 7 showed that immature wound healing-related mechanisms, such as protein metabolism and cell proliferation, were up-regulated at this time point. Furthermore, the immuno-inflammatory process was also up-regulated at the earlier time point. In contrast, by day 14, GO groups consistent with wound maturation, such as extracellular matrix formation, anatomical structure development and cell differentiation, were up-regulated. Furthermore, the functionally important GO categories of skeletal development, ossification and bone mineralization were up-regulated at day 14. Genes of interest that belonged to this group and were up-regulated at day 14 included growth and differentiation factors (Bmp2, Bmp3, Tgfb3), extracellular matrix proteins (osteocalcin, osteomodulin, stenniocalcin 1) and transcription factors (Runx2, Sox6, Satb2). Furthermore, a number of genes associated with Tgfβ/Bmp and Wnt signalling were also up-regulated. Besides skeletogenesis, genes associated with angiogenesis and neurogenesis were also up-regulated at day 14. Conclusions: The transcriptome associated with a maturing GBR-treated craniofacial bone defect is characterized by the down-regulation of the immuno-inflammatory response and up-regulation of skeletogeneis-, angiogenesis- and neurogenesis-associated genes. The Tgfβ/Bmp and Wnt signalling pathways play an important role in the regenerative process. To cite this article: Ivanovski S, Hamlet S, Retzepi M, Wall I, Donos N. Transcriptional profiling of "guided bone regeneration" in a critical size calvarial defect. Clin. Oral Impl. Res. 22, 2011; 382-389. PMID: 21561480 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | In vivo gene expression profile of guided bone regeneration associated with a microrough titanium surface. Clin Oral Implants Res. 2011 Apr;22(4):390-8 Authors: Donos N, Retzepi M, Wall I, Hamlet S, Ivanovski S Objectives: To determine the gene expression profile characteristic of "guided bone regeneration" associated with a microrough titanium surface. Material and methods: Critical-size calvarial defects were treated with the principle of "guided bone regeneration," whereby the extracranial barriers were either polished (SMO) or microrough (SLA) titanium disks. After 7 and 14 days, the contents of the regenerating defect were collected, RNA was extracted and microarray analysis was carried out. At each time point, the healing associated with the microrough surface was compared with that associated with the polished titanium surface. Results: On comparing the SLA and SMO profiles, there were few genes different at day 7 (∼250), whereas there were a large number of genes different at day 14 (∼6500). At day 14, the list of genes that were differentially regulated in response to the SMO and SLA surfaces had an over-representation of genes associated with the functionally relevant gene ontology categories of regeneration, skeletogenesis, mesenchymal cell differentiation, angiogenesis and neurogenesis. There were a greater number of genes within each of these functionally relevant categories that were up-regulated on the SLA surface compared with the SMO surface. The main signalling pathway that was differentially regulated between the two surfaces at day 14 was the Wnt signaling pathway. Conclusions: Minimal difference was observed between the SMO and the SLA samples at day 7, whereas significant differences were noted at day 14, including genes associated with a number of functionally relevant gene ontology groups. The differentially regulated biological processes provide an insight into the influence of surface topography on "guided bone regeneration" at the cellular and molecular level. To cite this article: Donos N, Retzepi M, Wall I, Hamlet S, Ivanovski S. In vivo gene expression profile of guided bone regeneration associated with a microrough titanium surface. Clin. Oral Impl. Res. 22, 2011; 390-398. PMID: 21561481 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Overexpression of bHLH transcription factors enhances neuronal differentiation of foetal human neural progenitor cells in various ways. Stem Cells Dev. 2011 May 11; Authors: Serre A, Snyder EY, Mallet J, Buchet D In a perspective of regenerative medicine, multipotent human neural progenitor cells (hNPCs) offer a therapeutic advantage over pluripotent stem cells in that they are already invariantly "neurally-committed" and lack tumorigenicity. However, some of their intrinsic properties, such as slow differentiation and uncontrolled multipotency, remain among the obstacles to their routine use for transplantation. While rodent NPCs have been genetically modified in vitro to overcome some of these limitations, the translation of this strategy to human cells remains in its early stages. In the present study, we compare the actions of four basic helix-loop-helix (bHLH) transcription factors on the proliferation, specification, and terminal differentiation of hNPCs isolated from the foetal dorsal telencephalon. Consistent with their proneural activity, Ngn1, Ngn2, Ngn3 and Mash1 prompted rapid commitment of the cells. While the Ngns induced a decrease in proliferation, Mash1 maintained committed progenitors in a proliferative state. As opposed to Ngn1 and Ngn3 which had no effect on glial differentiation, Ngn2 induced an increase in astrocytes in addition to neurons, while Mash1 led to both neuronal and oligodendroglial specification. GABAergic, cholinergic, and motor neuron differentiation was considerably increased by overexpression of Ngn2, and to a lesser extent of Ngn3 and Mash1. Thus, we provide evidence that hNPCs can be efficiently, rapidly, and safely expanded in vitro as well as rapidly differentiated towards mature neural (typically neuronal) lineages by the overexpression of select proneural genes. PMID: 21561385 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Transcriptional Activation of Histone H4 by C/EBP{beta} during the Mitotic Clonal Expansion of 3T3-L1 Adipocyte Differentiation. Mol Biol Cell. 2011 May 11; Authors: Zhang YY, Li X, Qian SW, Guo L, Huang HY, He Q, Liu Y, Ma CG, Tang QQ CCAAT enhancer binding protein β (C/EBPβ) is required for both mitotic clonal expansion (MCE) and terminal differentiation during 3T3-L1 adipocyte differentiation program. While the mechanism of C/EBPβ during terminal differentiation is well understood, the mechanism of C/EBPβ in MCE is not. Evidences are provided in this report that histone H4, the most conserved cell cycle-related histone whose change is strictly correlated with DNA content change during cell cycle, is transcriptionally activated by C/EBPβ during the MCE. The expression of histone H4 was increased at 16 hours after induction when 3T3-L1 preadipocytes synchronously re-enter S phase, which is correlated with the sequential phosphorylation and activation of C/EBPβ, and the expression was partially suppressed when A-C/EBP (dominant negative for C/EBP protein) was over-expressed. One C/EBP binding site was identified in one of the histone H4 gene promoter (hist4h4), confirmed by both EMSA and ChIP assay. C/EBP binding sites were also found in 9 of 11 other histone H4 promoters, which can also be transactivated by C/EBPβ. Knockdown of C/EBPβ by stealth siRNA partially decreased the H4 gene expression and arrested the cells in the G1 phase as indicated by BrdU incorporation and FACS analysis of DNA content. This study provides new insights to understand why C/EBPβ is required for MCE during 3T3-L1 adipocyte differentiation, and why C/EBPβ plays important roles in the proliferation of other cell types. PMID: 21562223 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Induction of functional hepatocyte-like cells from mouse fibroblasts by defined factors. Nature. 2011 May 11; Authors: Huang P, He Z, Ji S, Sun H, Xiang D, Liu C, Hu Y, Wang X, Hui L The generation of functional hepatocytes independent of donor liver organs is of great therapeutic interest with regard to regenerative medicine and possible cures for liver disease. Induced hepatic differentiation has been achieved previously using embryonic stem cells or induced pluripotent stem cells. Particularly, hepatocytes generated from a patient's own induced pluripotent stem cells could theoretically avoid immunological rejection. However, the induction of hepatocytes from induced pluripotent stem cells is a complicated process that would probably be replaced with the arrival of improved technology. Overexpression of lineage-specific transcription factors directly converts terminally differentiated cells into some other lineages, including neurons, cardiomyocytes and blood progenitors; however, it remains unclear whether these lineage-converted cells could repair damaged tissues in vivo. Here we demonstrate the direct induction of functional hepatocyte-like (iHep) cells from mouse tail-tip fibroblasts by transduction of Gata4, Hnf1α and Foxa3, and inactivation of p19(Arf). iHep cells show typical epithelial morphology, express hepatic genes and acquire hepatocyte functions. Notably, transplanted iHep cells repopulate the livers of fumarylacetoacetate-hydrolase-deficient (Fah(-/-)) mice and rescue almost half of recipients from death by restoring liver functions. Our study provides a novel strategy to generate functional hepatocyte-like cells for the purpose of liver engineering and regenerative medicine. PMID: 21562492 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Scalable robotic biofabrication of tissue spheroids. Biofabrication. 2011 May 12;3(2):025002 Authors: Mehesz AN, Brown J, Hajdu Z, Beaver W, da Silva JV, Visconti RP, Markwald RR, Mironov V Development of methods for scalable biofabrication of uniformly sized tissue spheroids is essential for tissue spheroid-based bioprinting of large size tissue and organ constructs. The most recent scalable technique for tissue spheroid fabrication employs a micromolded recessed template prepared in a non-adhesive hydrogel, wherein the cells loaded into the template self-assemble into tissue spheroids due to gravitational force. In this study, we present an improved version of this technique. A new mold was designed to enable generation of 61 microrecessions in each well of a 96-well plate. The microrecessions were seeded with cells using an EpMotion 5070 automated pipetting machine. After 48 h of incubation, tissue spheroids formed at the bottom of each microrecession. To assess the quality of constructs generated using this technology, 600 tissue spheroids made by this method were compared with 600 spheroids generated by the conventional hanging drop method. These analyses showed that tissue spheroids fabricated by the micromolded method are more uniform in diameter. Thus, use of micromolded recessions in a non-adhesive hydrogel, combined with automated cell seeding, is a reliable method for scalable robotic fabrication of uniform-sized tissue spheroids. PMID: 21562365 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Synthetic Chemoselective Rewiring of Cell Surfaces: Generation of Three-Dimensional Tissue Structures. J Am Chem Soc. 2011 May 11; Authors: Dutta D, Pulsipher A, Luo W, Yousaf MN Proper cell-cell communication through physical contact is crucial for a range of fundamental biological processes including, cell proliferation, migration, differentiation, and apoptosis and for the correct function of organs and other multicellular tissues. The spatial and temporal arrangements of these cellular interactions in vivo are dynamic and lead to higher-order function that is extremely difficult to recapitulate in vitro. The development of three-dimensional (3D), in vitro model systems to investigate these complex, in vivo interconnectivities would generate novel methods to study the biochemical signaling of these processes, as well as provide platforms for tissue engineering technologies. Herein, we develop and employ a strategy to induce specific and stable cell-cell contacts in 3D through chemoselective cell-surface engineering based on liposome delivery and fusion to display bio-orthogonal functional groups from cell membranes. This strategy uses liposome fusion for the delivery of ketone or oxyamine groups to different populations of cells for subsequent cell assembly via oxime ligation. We demonstrate how this method can be used for several applications including, the delivery of reagents to cells for fluorescent labeling and cell-surface engineering, the formation of small, 3D spheroid cell assemblies, and the generation of large and dense, 3D multilayered tissue-like structures for tissue engineering applications. PMID: 21561150 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The efficacy of allogeneic mesenchymal precursor cells for the repair of an ovine tibial segmental defect. Vet Comp Orthop Traumatol. 2011;24(2):113-21 Authors: Field JR, McGee M, Stanley R, Ruthenbeck G, Papadimitrakis T, Zannettino A, Gronthos S, Itescu S Synthetic void-fillers offer an alternative to autograft or allograft bone in the repair of segmental defects. However, the reparative process is delayed as only osteoconductive elements are present. The inclusion of pluripotential cells may resolve this limitation, and the use of allogeneic tissue provides the opportunity for an off-the-shelf remedy. The current study evaluated the utilisation of mesenchymal precursor cells (MPC) for the repair of an ovine critical-size tibial segmental defect. PMID: 21225086 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication and characterization of nano-composite scaffold of PLLA/silane modified hydroxyapatite. Med Eng Phys. 2010 May;32(4):391-7 Authors: Wang X, Song G, Lou T In order to improve the interfacial connection of hydroxyapatite (HAP) to poly-l-lactic acid (PLLA), gamma-methacryloxypropyl-trimethoxysilane (gamma-MPS) was used as a coupling agent to modify the surface of nano-HAP (NHAP) particles. The FTIR and XPS results showed gamma-MPS was successfully bonded on the surface of NHAP. Silane modified nano-HAP (MNHAP) and PLLA were fabricated to nano-composite scaffold by a thermally induced phase separation method. The characterization of the composite scaffold showed that the scaffold had a nano-fibrous PLLA network (fiber size 100-800 nm), an interconnective microporous structure (1-8 microm) and high porosity (>90%). MNHAP was homogeneously distributed in the scaffold, also partly set in the nano-PLLA fibers. As a result, the compressive modulus and the protein adsorption of PLLA/MNHAP (80:20, w/w) composite scaffold increased to 4.2-fold and 2.8-fold compared with those of a pure PLLA scaffold. Incorporating MNHAP into PLLA network also buffered the pH reduction and reduced the weight loss in vitro degradation significantly. PMID: 20189867 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Pentapeptide-modified poly(N,N-diethylacrylamide) hydrogel scaffolds for tissue engineering. J Biomed Mater Res B Appl Biomater. 2011 May 11; Authors: Horák D, Matulka K, Hlídková H, Lapčíková M, Beneš MJ, Jaroš J, Hampl A, Dvořák P Poly(N,N-diethylacrylamide) (PDEAAm) hydrogel scaffolds were prepared by radical copolymerization of N,N-diethylacrylamide (DEAAm), N,N'-methylenebisacrylamide and methacrylic acid in the presence of (NH(4) )(2) SO(4) or NaCl. The hydrogels were characterized by low-vacuum scanning electron microscopy in the water-swollen state, water and cyclohexane regain, and by mercury porosimetry. The pentapeptide, YIGSR-NH(2) , was immobilized on the hydrogel. Human embryonic stem cells (hESCs) were cultured with the hydrogels to test their biocompatibility. The results suggest that the PDEAAm hydrogel scaffolds are nontoxic and support hESC attachment and proliferation, and that interconnected pores of the scaffolds are important for hESC cultivation. Immobilization of YIGSR-NH(2) pentapeptide on the PDEAAm surface improved both adhesion and growth of hESCs compared with the unmodified hydrogel. The YIGSR-NH(2) -modified PDEAAm hydrogels may be a useful tool for tissue-engineering purposes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011. PMID: 21563303 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication of 2D protein microstructures and 3D polymer-protein hybrid microstructures by two-photon polymerization. Biofabrication. 2011 May 12;3(2):025003 Authors: Engelhardt S, Hoch E, Borchers K, Meyer W, Krüger H, Tovar GE, Gillner A Two-photon polymerization (TPP) offers the possibility of creating artificial cell scaffolds composed of micro- and nanostructures with spatial resolutions of less than 1 µm. For use in tissue engineering, the identification of a TPP-processable polymer that provides biocompatibility, biofunctionality and appropriate mechanical properties is a difficult task. ECM proteins such as collagen or fibronectin, which could mimic native tissues best, often lack the mechanical stability. Hence, by generating polymer-protein hybrid structures, the beneficial properties of proteins can be combined with the advantageous characteristics of polymers, such as sufficient mechanical stability. This study describes three steps toward facilitated application of TPP for biomaterial generation. (1) The efficiency of a low-cost ps-laser source is compared to a fs-laser source by testing several materials. A novel photoinitiator for polymerization with a ps-laser source is synthesized and proved to enable increased fabrication throughput. (2) The fabrication of 3D-microstructures with both systems and the fabrication of polymer-protein hybrid structures are demonstrated. (3) The tissue engineering capabilities of TPP are demonstrated by creating cross-linked gelatin microstructures, which clearly forced porcine chondrocytes to adapt their cell morphology. PMID: 21562366 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fabrication and characters of a corneal endothelial cells scaffold based on chitosan. J Mater Sci Mater Med. 2011 Jan;22(1):175-83 Authors: Liang Y, Liu W, Han B, Yang C, Ma Q, Zhao W, Rong M, Li H A novel chitosan-based membrane that made of hydroxyethyl chitosan, gelatin and chondroitin sulfate was used as a carrier of corneal endothelial cells. The characteristics of the blend membrane including transparency, equilibrium water content, ion and glucose permeability were determined. The results showed that the optical transparency of the membrane was as good as the natural human cornea. The water content of this scaffold was 81.32% which was remarkably close to the native cornea. The membrane had a good ion permeability and its glucose permeability was even higher than natural human cornea. The cultured rabbit corneal endothelial cells formed a monolayer on the membrane. The results demonstrated that the membrane was suitable for corneal endothelial cells to attach and grow on it. In addition, the membranes in vivo could be degraded steadily with less inflammation and showed a good histocompatibility. These results demonstrated that the hydroxyethyl chitosan-chondroitin sulfate-gelatin blend membrane can potentially be used as a carrier for corneal endothelial cell transplantation. PMID: 21107657 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A Systematic Review of the Use of Platelet-Rich Plasma in Sports Medicine as a New Treatment for Tendon and Ligament Injuries. Clin J Sport Med. 2011 May 10; Authors: Taylor DW, Petrera M, Hendry M, Theodoropoulos JS OBJECTIVE:: To evaluate, through a systematic review of the current literature, the evidence-based outcomes of the use of platelet-rich plasma (PRP) for the treatment of tendon and ligament injuries. DATA SOURCES:: A search of English-language articles was performed in PubMed and EMBASE using keywords "PRP," "platelet plasma," and "platelet concentrate" combined with "tendon" and then "ligament" independently. The search was conducted through September 2010. STUDY SELECTION:: Search was limited to in vivo studies. Nonhuman studies were excluded. Tissue engineering strategies, which included a combination of PRP with additional cell types (bone marrow), were also excluded. Articles with all levels of evidence were included. Thirteen of 32 retrieved articles respected the inclusion criteria. DATA EXTRACTION:: The authors reviewed and tabulated data according to the year of study and journal, study type and level of evidence, patient demographics, method of PRP preparation, site of application, and outcomes. DATA SYNTHESIS:: The selected studies focused on the application of PRP in the treatment of patellar and elbow tendinosis, Achilles tendon injuries, rotator cuff repair, and anterior cruciate ligament (ACL) reconstruction. Seven studies demonstrated favorable outcomes in tendinopathies in terms of improved pain and functional scores. In 3 studies on the use of PRP in ACL reconstruction, no statistically significant differences were seen with regard to clinical outcomes, tunnel widening, and graft integration. One study examined the systemic effects after the local PRP application for patellar and elbow tendinosis. CONCLUSIONS:: Presently, PRP use in tendon and ligament injuries has several potential advantages, including faster recovery and, possibly, a reduction in recurrence, with no adverse reactions described. However, only 3 randomized clinical trials have been conducted. PMID: 21562414 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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