|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | LOS ANGELES -- The California stem cell agency today awarded $67 million for translational research and approved one appeal from a scientist whose application was turned down by grant reviewers.
The grants are a "key element of CIRM's pipeline to the clinic," directors were told. The research is aimed at creating a "development candidate ready for IND-enabling preclinical development" or making | | | | | | | | | | | | | | | | | | | | | | | | | In Vivo Assessment of the Electrophysiological Integration and Arrhythmogenic Risk of Myocardial Cell Transplantation Strategies. Stem Cells. 2010 Oct 19; Authors: Gepstein L, Ding C, Rehemedula D, Wilson EE, Yankelson L, Caspi O, Gepstein A, Huber I, Olgin JE Cell-replacement strategies are promising interventions aiming to improve myocardial performance. Yet, the electrophysiological impact of these approaches has not been elucidated. We assessed the electrophysiological consequences of grafting of two candidate cell types; skeletal myoblasts and human embryonic stem cell-derived cardiomyocytes (hESC-CMs).The fluorescently-labeled (DiO) candidate cells were grafted into the rat's LV myocardium. Two weeks later, optical mapping was performed using the Langendorff-perfused rat heart preparation. Images were obtained with appropriate filters to delineate the heart's anatomy, to identify the DiO-labeled cells, and to associate this information with the voltage-mapping data (using the voltage-sensitive dye PGH-I). Histological examination revealed the lack of gap junctions between grafted skeletal myotubes and host cardiomyocytes. In contrast, positive Cx43 immunostaining was observed between donor and host cardiomyocytes in the hESC-CMs-transplanted hearts. Optical mapping demonstrated either normal conduction (4 out of 6) or minimal conduction slowing (2 out of 6) at the hESC-CMs engraftment sites. In contrast marked slowing of conduction or conduction block was seen (7 out of 8) at the myoblast transplantation sites. Ventricular arrhythmias could not be induced in the hESC-CM hearts following programmed electrical stimulation, but were inducible in 50% of the myoblast-engrafted hearts.In summary, a unique method for assessment of the electrophysiological impact of myocardial cell therapy is presented. Our results demonstrate the ability of hESC-CMs to functionally integrate with host tissue. In contrast, transplantation of cells that do not form gap junctions (skeletal myoblats) led to localized conduction disturbances and to the generation of a pro-arrhythmogenic substrate. PMID: 20960511 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Surfactant-free poly(lactide-co-glycolide) honeycomb films for tissue engineering: relating solvent, monomer ratio and humidity to scaffold structure. Biotechnol Lett. 2010 Oct 20; Authors: Wu X, Jones MD, Davidson MG, Chaudhuri JB, Ellis MJ One-step surfactant-free, water-droplet templating has been developed as a fabrication method for a poly(lactide-co-glycolide) (PLGA) film that can be used as a model to investigate the relationship between solvent, monomer ratio, polymer concentration and humidity on its structure. The resulting material is a honeycomb-structured film. Formation of this structure was highly sensitive to solvent, monomer ratio, polymer concentration and humidity. Surfactant-free, water-droplet templating thus allows investigation of fabrication parameters and that PLGA monomer ratio selection is important for scaffold structure but not for MG63 cell attachment and proliferation. PMID: 20960219 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Transmembrane potential of GlyCl-expressing instructor cells induces a neoplastic-like conversion of melanocytes via a serotonergic pathway. Dis Model Mech. 2010 Oct 19; Authors: Blackiston D, Adams DS, Lemire JM, Lobikin M, Levin M Understanding the mechanisms that coordinate stem cell behavior within the host is a high priority for developmental biology, regenerative medicine and oncology. Endogenous ion currents and voltage gradients function alongside biochemical cues during pattern formation and tumor suppression, but it is not known whether bioelectrical signals are involved in the control of stem cell progeny in vivo. We studied Xenopus laevis neural crest, an embryonic stem cell population that gives rise to many cell types, including melanocytes, and contributes to the morphogenesis of the face, heart and other complex structures. To investigate how depolarization of transmembrane potential of cells in the neural crest's environment influences its function in vivo, we manipulated the activity of the native glycine receptor chloride channel (GlyCl). Molecular-genetic depolarization of a sparse, widely distributed set of GlyCl-expressing cells non-cell-autonomously induces a neoplastic-like phenotype in melanocytes: they overproliferate, acquire an arborized cell shape and migrate inappropriately, colonizing numerous tissues in a metalloprotease-dependent fashion. A similar effect was observed in human melanocytes in culture. Depolarization of GlyCl-expressing cells induces these drastic changes in melanocyte behavior via a serotonin-transporter-dependent increase of extracellular serotonin (5-HT). These data reveal GlyCl as a molecular marker of a sparse and heretofore unknown cell population with the ability to specifically instruct neural crest derivatives, suggest transmembrane potential as a tractable signaling modality by which somatic cells can control stem cell behavior at considerable distance, identify a new biophysical aspect of the environment that confers a neoplastic-like phenotype upon stem cell progeny, reveal a pre-neural role for serotonin and its transporter, and suggest a novel strategy for manipulating stem cell behavior. PMID: 20959630 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | LOS ANGELES – The board of the California stem cell agency begins its meeting this morning with consideration of requests for $80 million for translational research high on its agenda, including four appeals by scientists rejected by reviewers.
Also on today's agenda is a proposal for modification of the grant appeal process. It would provide a formal way for the CIRM board to send a grant back | | | | | | | | | | | | | | | | | | | | | | | | | Surfactant-free poly(lactide-co-glycolide) honeycomb films for tissue engineering: relating solvent, monomer ratio and humidity to scaffold structure. Biotechnol Lett. 2010 Oct 20; Authors: Wu X, Jones MD, Davidson MG, Chaudhuri JB, Ellis MJ One-step surfactant-free, water-droplet templating has been developed as a fabrication method for a poly(lactide-co-glycolide) (PLGA) film that can be used as a model to investigate the relationship between solvent, monomer ratio, polymer concentration and humidity on its structure. The resulting material is a honeycomb-structured film. Formation of this structure was highly sensitive to solvent, monomer ratio, polymer concentration and humidity. Surfactant-free, water-droplet templating thus allows investigation of fabrication parameters and that PLGA monomer ratio selection is important for scaffold structure but not for MG63 cell attachment and proliferation. PMID: 20960219 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chondrogenesis of mesenchymal stem cells: role of tissue source and inducing factors. Stem Cell Res Ther. 2010 Oct 13;1(4):31 Authors: Boeuf S, Richter W ABSTRACT: Multipotent mesenchymal stromal cells (MSCs) are an attractive cell source for cell therapy in cartilage. Although their therapeutic potential is clear, the requirements and conditions for effective induction of chondrogenesis in MSCs and for the production of a stable cartilaginous tissue by these cells are far from being understood. Different sources of MSCs have been considered for cartilage tissue engineering, mainly based on criteria of availability, as for adipose tissue, or of proximity to cartilage and the joint environment in vivo, as for bone marrow and synovial tissues. Focussing on human MSCs, this review will provide an overview of studies featuring comparative analysis of the chondrogenic differentiation of MSCs from different sources. In particular, it will examine the influence of the cells' origin on the requirements for the induction of chondrogenesis and on the phenotype achieved by the cells after differentiation. PMID: 20959030 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | International prevalidation studies of the EpiDerm 3D human reconstructed skin micronucleus (RSMN) assay: transferability and reproducibility. Mutat Res. 2010 Aug 30;701(2):123-31 Authors: Aardema MJ, Barnett BC, Khambatta Z, Reisinger K, Ouedraogo-Arras G, Faquet B, Ginestet AC, Mun GC, Dahl EL, Hewitt NJ, Corvi R, Curren RD Recently, a novel in vitro reconstructed skin micronucleus (RSMN) assay incorporating the EpiDerm 3D human skin model (Curren et al., Mutat. Res. 607 (2006) 192-204; Mun et al., Mutat. Res. 673 (2009) 92-99) has been shown to produce comparable data when utilized in three different laboratories in the United States (Hu et al., Mutat. Res. 673 (2009) 100-108). As part of a project sponsored by the European cosmetics companies trade association (COLIPA), with a contribution from the European Center for the Validation of Alternative Methods (ECVAM), international prevalidation studies of the RSMN assay have been initiated. The assay was transferred and optimized in two laboratories in Europe, where dose-dependent, reproducibly positive results for mitomycin C and vinblastine sulfate were obtained. Further intra- and inter-laboratory reproducibility of the RSMN assay was established by testing three coded chemicals, N-ethyl-N-nitrosourea, cyclohexanone, and mitomycin C. All chemicals were correctly identified by all laboratories as either positive or negative. These results support the international inter-laboratory and inter-experimental reproducibility of the assay and reinforce the conclusion that the RSMN assay in the EpiDerm 3D human skin model is a valuable in vitro method for assessment of genotoxicity of dermally applied chemicals. PMID: 20621637 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Construction of tissue-engineered cartilage using human placenta-derived stem cells. Sci China Life Sci. 2010 Feb;53(2):207-14 Authors: Liu D, Hui H, Chai X, Wang B, Qiu J Human placenta-derived stem cells (hPDSCs) were isolated by trypsinization and further induced into cartilage cells in vitro. The engineered cartilage was constructed by combining hPDSCs with collagen sponge and the cartilage formation was observed by implantation into nude mice. Results showed that hPDSCs featured mesenchymal stem cells and maintained proliferation in vitro for over 30 passages while remaining undifferentiated. All results indicated that hPDSCs have the potential to differentiate into functional cartilage cells in vitro when combined with collagen sponge, which provided experimental evidence for prospective clinical application. PMID: 20596829 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of media mixing on ECM assembly and mechanical properties of anatomically-shaped tissue engineered meniscus. Biomaterials. 2010 Sep;31(26):6756-63 Authors: Ballyns JJ, Wright TM, Bonassar LJ This study investigated the hypothesis that controlled media mixing will enhance tissue formation and increase mechanical properties of anatomically-shaped tissue engineered menisci. Bovine meniscal fibrochondrocytes were seeded in 2% w/v alginate, cross-linked with 0.02 g/mL CaSO(4), and injected into molds of menisci. Engineered menisci were incubated for up to 6 weeks. A mixing media bioreactor was designed to ensure proper mixing of culture medium while protecting constructs from the spinning impeller. Impeller speeds were calibrated to produce Reynolds number (Re) of 0.5, 2.9, 5.8, 10.2, and 21.8. Constructs were divided a tested in confined compression and in tension to determine the equilibrium and tensile moduli, respectively. Media stimulation resulted in a 2-5 fold increase in mechanical properties and a 2-3 fold increase in matrix accumulation in constructs over 6 weeks in culture. Benefits from mixing stimulation for collagen accumulation and compressive modulus appeared to peak near Re 2.9, and decreased with increased mixing intensity. This study suggests that fluid mixing can be optimized to enhance mechanical properties of anatomically-shaped engineered constructs. PMID: 20541796 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells in cartilage repair: state of the art and methods to monitor cell growth, differentiation and cartilage regeneration. Curr Med Chem. 2010;17(21):2274-91 Authors: Galle J, Bader A, Hepp P, Grill W, Fuchs B, Käs JA, Krinner A, Marquass B, Müller K, Schiller J, Schulz RM, von Buttlar M, von der Burg E, Zscharnack M, Löffler M Degenerative joint diseases caused by rheumatism, joint dysplasia or traumata are particularly widespread in countries with high life expectation. Although there is no absolutely convincing cure available so far, hyaline cartilage and bone defects resulting from joint destruction can be treated today by appropriate transplantations. Recently, procedures were developed based on autologous chondrocytes from intact joint areas. The chondrocytes are expanded in cell culture and subsequently transplanted into the defect areas of the affected joints. However, these autologous chondrocytes are characterized by low expansion capacity and the synthesis of extracellular matrix of poor functionality and quality. An alternative approach is the use of adult mesenchymal stem cells (MSCs). These cells effectively expand in 2D culture and have the potential to differentiate into various cell types, including chondrocytes. Furthermore, they have the ability to synthesize extracellular matrix with properties mimicking closely the healthy hyaline joint cartilage. Beside a more general survey of the architecture of hyaline cartilage, its composition and the pathological processes of joint diseases, we will describe here which advances were achieved recently regarding the development of closed, aseptic bioreactors for the production of autologous grafts for cartilage regeneration based on MSCs. Additionally, a novel mathematical model will be presented that supports the understanding of the growth and differentiation of MSCs. It will be particularly emphasized that such models are helpful to explain the well-known fact that MSCs exhibit improved growth properties under reduced oxygen pressure and limited supply with nutrients. Finally, it will be comprehensively shown how different analytical methods can be used to characterize MSCs on different levels. Besides discussing methods for non-invasive monitoring and tracking of the cells and the determination of their elastic properties, mass spectrometric methods to evaluate the lipid compositions of cells will be highlighted. PMID: 20459378 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Proteasome activity correlates with male BMI and contributes to the differentiation of adipocyte in hADSC. Endocrine. 2010 Apr;37(2):274-9 Authors: Sakamoto K, Sato Y, Sei M, Ewis AA, Nakahori Y We have previously reported that 26S proteasome subunit mRNA expressions correlate with male body mass index (BMI). In this study, to investigate whether proteasome activities are correlated with BMI, we recruited 61 healthy young Japanese male subjects, measured proteasome activities in their plasma, and correlated them with their BMI and various metabolic factors. We found that among three different proteasome activities, chymotrypsin-like activity in plasma was positively correlated with BMI in healthy Japanese male subjects. Furthermore, we analyzed proteasome activity in vitro during the differentiation of human adipose-derived stem cell (hADSC) into mature adipocytes. In the early stage of differentiation, proteasome activity was at its highest level, and proteasome inhibitor could inhibit hADSC adipocyte differentiation. Our findings suggest that proteasome is an important controlling factor for the development of obesity and adipogenesis. PMID: 20960262 [PubMed - in process] | | | | | | | | | |  | |  | |  |
No comments:
Post a Comment