|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | The California stem cell agency responded today to an item reporting dissatisfaction on the part of the biotech industry concerning its meager share of the $1 billion that CIRM has awarded so far.
Don Gibbons, chief communications officer for the agency, filed his remarks earlier today as a comment on the second piece we wrote on the subject. (Here is a link to the first.) Because of the | | | | | | | | | | | | | | | | | | | | | | | | | Differentiation of mesenchymal stem cells in chitosan scaffolds with double micro and macroporosity. J Biomed Mater Res A. 2010 Oct 5; Authors: García Cruz DM, Gomes M, Reis RL, Moratal D, Salmerón-Sánchez M, Gómez Ribelles JL, Mano JF Bone Marrow mesenchymal stem cells can be induced to differentiate into osteoblasts to regenerate damaged bone tissue using tissue engineering techniques. In this study, we examine the use of chitosan scaffolds with double pore structure prepared by an innovative method that combines freeze gelation (that produces micropores) and particle leaching out technique (that produces interconnected spherical macropores) seeking to enhance the osteogenic differentiation of goat bone marrow stromal cells (GBMSCs). The double pore architecture of the scaffold was characterized by scanning electron microscopy (SEM), microcomputed tomography and confocal laser scanning microscopy. The obtained hierarchical pore structure allowed very efficient seeding of GBMSCs that are able to occupy the whole volume of the scaffold, showing good adhesion and proliferation. GBMSCs were differentiated into osteoblasts as indicated by alkaline phosphatase activity and osteocalcin expression. The results of this study demonstrate that chitosan scaffold may be promising biomaterial for bone regeneration. © 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010. PMID: 20925083 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Simultaneous expansion and harvest of hematopoietic stem cells and mesenchymal stem cells derived from umbilical cord blood. J Mater Sci Mater Med. 2010 Oct 6; Authors: Kedong S, Xiubo F, Tianqing L, Macedo HM, Lili J, Meiyun F, Fangxin S, Xuehu M, Zhanfeng C The simultaneous expansion and harvest of hematopoietic stem cells and mesenchymal stem cells derived from umbilical cord blood were carried out using bioreactors. The co-culture of umbilical cord blood (UCB)-derived hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) was performed within spinner flasks and a rotating wall vessel (RWV) bioreactor using glass-coated styrene copolymer (GCSC) microcarriers. The medium used was composed of serum-free IMDM containing a cocktail of SCF 15 ng·mL(-1), FL 5 ng·mL(-1), TPO 6 ng·mL(-1), IL-3 15 ng·mL(-1), G-CSF 1 ng·mL(-1) and GM-CSF 5 ng·mL(-1). Accessory stromal cells derived from normal allogeneic adipose tissue were encapsulated in alginate-chitosan (AC) beads and used as feeding cells. The quality of the harvested UCB-HSCs and MSCs was assessed by immunophenotype analysis, methylcellulose colony and multi-lineage differentiation assays. After 12 days of culture, the fold-expansion of total cell numbers, colony-forming units (CFU-C), CD34(+)/CD45(+)/CD105(-) (HSCs) cells and CD34(-)/CD45(-)/CD105(+) (MSCs) cells using the RWV bioreactor were (3.7 ± 0.3)- , (5.1 ± 1.2)- , (5.2 ± 0.4)- , and (13.9 ± 1.2)-fold respectively, significantly better than those obtained using spinner flasks. Moreover, UCB-HSCs and UCB-MSCs could be easily separated by gravity sedimentation after the co-culture period as only UCB-MSCs adhered on to the microcarriers. Simultaneously, we found that the fibroblast-like cells growing on the surface of the GCSC microcarriers could be induced and differentiated towards the osteoblastic, chondrocytic and adipocytic lineages. Phenotypically, these cells were very similarly to the MSCs derived from bone marrow positively expressing the MSCs-related markers CD13, CD44, CD73 and CD105, while negatively expressing the HSCs-related markers CD34, CD45 and HLA-DR. It was thus demonstrated that the simultaneous expansion and harvest of UCB-HSCs and UCB-MSCs is possible to be accomplished using a feasible bioreactor culture system such as the RWV bioreactor with the support of GCSC microcarriers. PMID: 20924776 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Patterning osteogenesis by inducible gene expression in microfluidic culture systems. Integr Biol (Camb). 2010 Oct 5; Authors: Zhang Y, Gazit Z, Pelled G, Gazit D, Vunjak-Novakovic G The development of transitional interfacial zones between adjacent tissues remains a significant challenge for developing tissue engineering and regenerative medicine strategies. Using osteogenic differentiation as a model, we describe a novel approach to spatially regulate expression and secretion of the bone morphogenetic protein (BMP-2) in a two-dimensional field of cultured cells, by flow patterning the modulators of inducible BMP-2 gene expression. We first demonstrate control of gene expression, and of osteogenic differentiation of the cell line with inducible expression of BMP-2. Then we design laminar flow systems, with patterned delivery of Doxycycline (Dox), the expression modulator of BMP-2. The patterned concentration profiles were verified by computational simulation and dye separation experiments. Patterned differentiation experiments conducted in the flow systems for a period of three weeks showed the Dox concentration dependent osteogenic differentiation, as evidenced by mineral deposition. In summary, by combining inducible gene expression with laminar flow technologies, this study provided an innovative way to engineer tissue interfaces. PMID: 20924519 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cells in bone tissue engineering. Biomed Mater. 2010 Oct 6;5(6):062001 Authors: Seong JM, Kim BC, Park JH, Kwon IK, Mantalaris A, Hwang YS Bone tissue engineering has been one of the most promising areas of research, providing a potential clinical application to cure bone defects. Recently, various stem cells including embryonic stem cells (ESCs), bone marrow-derived mesenchymal stem cells (BM-MSCs), umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs), adipose tissue-derived stem cells (ADSCs), muscle-derived stem cells (MDSCs) and dental pulp stem cells (DPSCs) have received extensive attention in the field of bone tissue engineering due to their distinct biological capability to differentiate into osteogenic lineages. The application of these stem cells to bone tissue engineering requires inducing in vitro differentiation of these cells into bone forming cells, osteoblasts. For this purpose, efficient in vitro differentiation towards osteogenic lineage requires the development of well-defined and proficient protocols. This would reduce the likelihood of spontaneous differentiation into divergent lineages and increase the available cell source for application to bone tissue engineering therapies. This review provides a critical examination of the various experimental strategies that could be used to direct the differentiation of ESC, BM-MSC, UCB-MSC, ADSC, MDSC and DPSC towards osteogenic lineages and their potential applications in tissue engineering, particularly in the regeneration of bone. PMID: 20924139 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A modified double-emulsion method for the preparation of daunorubicin-loaded polymeric nanoparticle with enhanced in vitro anti-tumor activity. Biomed Mater. 2010 Oct 6;5(6):065002 Authors: Liu J, Qiu Z, Wang S, Zhou L, Zhang S The encapsulation of hydrophilic drug in polymeric nanoparticles with high loading remains a challenge due to the rapid penetration of the drug to the external aqueous phase. In order to improve the encapsulation efficiency of daunorubicin (DNR) in poly(d,l-lactic-co-glycolic acid (PLGA) and poly(d,l-lactic acid) (PDLLA) nanoparticles, we fabricated a series of DNR-loaded nanoparticles using a modified double-emulsion solvent evaporation/diffusion method, which introduced a partially water-soluble organic solvent into the particle formation. The influence of various preparation parameters was investigated systematically, such as the ratio of organic solvent, the type of surfactant, the type of polymers and the molecular weight. Results showed that regular spherical PLGA nanoparticles with diameters of 200-300 nm could be produced with a remarkably high DNR encapsulation efficiency (>80%) and loading (6.5% (w/w)). Upon encapsulation, the sustained release of DNR could be controlled over 2 weeks. The results of FT-IR and DSC analysis indicated that the encapsulated DNR in polymeric nanoparticles was inclusion, not absorption. Furthermore, optimized DNR/PLGA nanoparticles showed a significant enhancement of cellular uptake, higher cytotoxicity against HL-60 cells compared with free DNR. These results were potentially useful for the nanoparticle formulation of hydrophilic chemotherapeutic drugs that require efficient delivery to cancer cells as well as sustained release at the specific site. PMID: 20924138 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Improving bone marrow stromal cell attachment on chitosan/hydroxyapatite scaffolds by an immobilized RGD peptide. Biomed Mater. 2010 Oct 6;5(6):065001 Authors: Qu Z, Yan J, Li B, Zhuang J, Huang Y Ample cell adhesion to scaffolds is essential for effective bone tissue engineering. Chitosan/hydroxyapatite (CS/HA) scaffolds with channel-shaped and spherically shaped pore morphologies were prepared via in situ compositing hybridization in combination with lyophilization. The sizes of channel-shaped and spherically shaped pores of the CS/HA scaffolds were 150-650 µm and 3-15 µm, respectively. The RGD peptide (Arg-Gly-Asp) was bound to the surface of CS/HA scaffolds via physical adsorption. More than 63% of RGD present in a PBS solution spontaneously adsorbed onto CS/HA scaffolds. High numbers of viable bone marrow stromal cells (BMSCs) were observed by confocal and fluorescence microscopy for cells cultured on CS/HA scaffolds with and without RGD for 3 days. BMSCs on CS/HA scaffolds with RGD (RGD-CS/HA) were incubated for 4 h under standard culture conditions, and the degree of cell adhesion was calculated. Cell adhesion to RGD-CS/HA scaffolds with different RGD concentrations was 71.6% and 80.7%, respectively. This was 30.9% and 47.5% higher than adhesion to the CS/HA scaffold without RGD, respectively. BMSCs cultured on the scaffolds for 14 days with osteogenic supplements expressed 103% higher alkaline phosphatase on the RGD-CS/HA scaffold (0.001 97 ± 0.000 31 U/L/ng), than on the unmodified scaffold (0.000 97 ± 0.000 25 U/L/ng) (p < 0.01), indicating that a RGD peptide significantly promotes osteogenic differentiation of BMSCs on CS/HA scaffolds. The results of this study indicate that RGD-CS/HA scaffolds promote initial cell adhesion, spread and differentiation toward an osteogenic phenotype. PMID: 20924135 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteoblasts mineralization with Composite nanofibrous substrate for Bone tissue regeneration. Cell Biol Int. 2010 Oct 5; Authors: Jayarama Reddy V, V R GD, T S, D S, G D, S R Several studies are currently ongoing to construct synthetic bone-like materials with composites of natural and polymeric materials with hydroxyapatite (HA). The present study aims to fabricate composite nanofibrous substrate of Chitosan/HA (Chit/HA-80:25) prepared by dissolving in TFA/DCM (70:30 w/w) for 5 days and electrospun to fabricate a scaffold for bone tissue engineering. HA (25 wt%) was sonicated for 30 minutes to obtain a homogenous dispersion of nanoparticles within the chitosan (80 wt%) matrix for fabricating composite nanofibrous scaffold (Chit/HA). The nanofibers of chitosan and Chit/HA were obtained with fiber diameters of 274 ± 75 nm and 510 ± 198 nm, respectively and characterized by FESEM and FTIR. The interaction of human fetal osteoblasts (hFOB) and nanofibrous substrates were analyzed for cell morphology (FESEM), mineralization (ARS staining), quantification of minerals, and finally identified the elements present in Chit/HA/Osteoblasts by energy dispersive X-ray analysis (EDX). EDX analysis confirmed the spherulites contain calcium and phosphorous, the major constituents in calcium phosphate apatite, the mineral phase of the bone. Mineralization was increased significantly (p<0.001) upto 108% in Chit/HA compared to chitosan nanofibers. These results confirmed that the electrospun composite Chit/HA nanofibrous substrate have potential biocomposite material for the proliferation and mineralization of hFOBs required for enhanced bone tissue regeneration. Key words: Electrospinning, chitosan, hydroxyapatite, nanofibrous substrate, mineralization, bone tissue regeneration. PMID: 20923413 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A Galerkin-type finite element solution for simulation of mass diffusion in the application of tissue engineering: heterogeneous and non-porous media. Proc Inst Mech Eng H. 2010;224(8):1005-17 Authors: Mohammadi H, Mequanint K, Bahramian F This study is an effort to produce a generic and comprehensive solution to the simulation of mass diffusion through a multiphasic and heterogeneous material model. A Galerkin-type finite element formulation is developed to solve Fick's equation for steady-state and time-dependent analysis. The effect of the interface in modelling of a liquid-solid medium is presented in this work. To show the robustness of the proposed approach, the gas exchange (oxygen and carbon dioxide) process through the capillary network between the alveolar membrane and red blood cells has been analysed and then validated with experimental data. The current work is a significant asset to modelling the diffusion of oxygen between cells and scaffolds in tissue engineering or tissue regeneration/repair studies. It is one step towards the development of high-order elements for application of the simulation of mass transfer through a multiphasic and porous model with varying degrees of interconnectivity and pore size for tissue engineering applications. PMID: 20923117 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Three step derivation of cartilage like tissue from human embryonic stem cells by 2D-3D sequential culture in vitro and further implantation in vivo on alginate/PLGA scaffolds. J Biomed Mater Res A. 2010 Aug;94(2):539-46 Authors: Bai HY, Chen GA, Mao GH, Song TR, Wang YX In this study a three step culture system, 2D-3D sequential culture in vitro and further implantation in vivo was developed to induce human embryonic stem cells (hESCs) into cartilage like tissues. Five-day-old embryoid bodies were plated for chondrogenic induction for 27 days (step1), then the cells were suspended in alginate and seeded onto polylactic-co-glycolic acid (PLGA) scaffolds for 3D cultivation for 7 days (step 2) and the cells/alginate/PLGA complexes were further transplanted into nude mice for 8 weeks (step 3). At same time, some of complexes were cultured in vitro up to 8 weeks. At the end of step 1, cells exhibited fibroblast-like morphology and expressed chondrocyte-specific markers, Sox 9 and collagen II. During the following 8 weeks of 3D cultivation in vitro, cells displayed spherical morphology, decreased immunoreactivity to Sox-9 and increased one to collagen II, demonstrated further differentiation to mature chondrocyte. In implanted grafts, not only cells appeared typical chondrocytes shape and markers but also cartilage like tissues were formed. These results indicate that 2D-3D sequential culture in vitro is an efficient protocol to induce hESCs differentiates into chondrocytes, while the three step culture system may be an appropriate procedure to derive cartilage like tissues from hESCs. PMID: 20186773 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Repair of large cranial defects by hBMP-2 expressing bone marrow stromal cells: comparison between alginate and collagen type I systems. J Biomed Mater Res A. 2010 Aug;94(2):433-41 Authors: Chang SC, Chung HY, Tai CL, Chen PK, Lin TM, Jeng LB Despite a wide range of available sources for bone repair, significant limitations persist. To bioengineer bone, we have previously transferred adenovirus-mediated human BMP-2 gene into autologous bone marrow stromal cells (MSC). We have successfully repaired large, full thickness, cranial defects using this approach. We report now the effectiveness of various hydrogels as the scaffold for this type of bone regeneration, comparing specifically alginate with Type I collagen. Cultured MSC of miniature swine were infected with BMP-2 or beta-gal adenovirus 7 days before implantation. These cells were mixed with alginate, ultrapure alginate, alginate-RGD, or type I collagen to fabricate the MSC/biomaterial constructs. The results of cranial bone regeneration were assessed by gross examination, histology, 3D CT, and biomechanical tests at 6 weeks and 3 months after implantation. We found that the BMP-2 MSC/collagen type I construct, but not the beta-gal control, effectively achieved nearly complete repair of the cranial defects. No bone regeneration was observed with the other hydrogels. Biomechanical testing showed that the new bone strength was very close and only slightly inferior to that of normal cranial bone. Controlling for the integration of stem cells and ex vivo gene transfer, the alginate scaffolds has a significant negative impact on the success of the construct. Our study demonstrates better bone regeneration by collagen type I over alginate. This may have therapeutic implications for tissue engineered bone repair. PMID: 20186742 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Simultaneous expansion and harvest of hematopoietic stem cells and mesenchymal stem cells derived from umbilical cord blood. J Mater Sci Mater Med. 2010 Oct 6; Authors: Kedong S, Xiubo F, Tianqing L, Macedo HM, Lili J, Meiyun F, Fangxin S, Xuehu M, Zhanfeng C The simultaneous expansion and harvest of hematopoietic stem cells and mesenchymal stem cells derived from umbilical cord blood were carried out using bioreactors. The co-culture of umbilical cord blood (UCB)-derived hematopoietic stem cells (HSCs) and mesenchymal stem cells (MSCs) was performed within spinner flasks and a rotating wall vessel (RWV) bioreactor using glass-coated styrene copolymer (GCSC) microcarriers. The medium used was composed of serum-free IMDM containing a cocktail of SCF 15 ng·mL(-1), FL 5 ng·mL(-1), TPO 6 ng·mL(-1), IL-3 15 ng·mL(-1), G-CSF 1 ng·mL(-1) and GM-CSF 5 ng·mL(-1). Accessory stromal cells derived from normal allogeneic adipose tissue were encapsulated in alginate-chitosan (AC) beads and used as feeding cells. The quality of the harvested UCB-HSCs and MSCs was assessed by immunophenotype analysis, methylcellulose colony and multi-lineage differentiation assays. After 12 days of culture, the fold-expansion of total cell numbers, colony-forming units (CFU-C), CD34(+)/CD45(+)/CD105(-) (HSCs) cells and CD34(-)/CD45(-)/CD105(+) (MSCs) cells using the RWV bioreactor were (3.7 ± 0.3)- , (5.1 ± 1.2)- , (5.2 ± 0.4)- , and (13.9 ± 1.2)-fold respectively, significantly better than those obtained using spinner flasks. Moreover, UCB-HSCs and UCB-MSCs could be easily separated by gravity sedimentation after the co-culture period as only UCB-MSCs adhered on to the microcarriers. Simultaneously, we found that the fibroblast-like cells growing on the surface of the GCSC microcarriers could be induced and differentiated towards the osteoblastic, chondrocytic and adipocytic lineages. Phenotypically, these cells were very similarly to the MSCs derived from bone marrow positively expressing the MSCs-related markers CD13, CD44, CD73 and CD105, while negatively expressing the HSCs-related markers CD34, CD45 and HLA-DR. It was thus demonstrated that the simultaneous expansion and harvest of UCB-HSCs and UCB-MSCs is possible to be accomplished using a feasible bioreactor culture system such as the RWV bioreactor with the support of GCSC microcarriers. PMID: 20924776 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | The California Stem Cell Report has offered the state's stem cell agency and its directors an opportunity to respond at length in connection with the biotech industry's concerns about the paucity of awards to business.
BayBio, which represents the industry in Northern California, documented the complaints in a six-page paper in August, just two months after CIRM Chairman Robert Klein dismissed | | | | | | | | | | | | | | | | | | | | | | | | The California Stem Cell Report has offered the state's stem cell agency and its directors an opportunity to respond at length in connection with the biotech industry's concerns about the paucity of awards to business.
BayBio, which represents the industry in Northern California, documented the complaints in a six-page paper in August, just two months after CIRM Chairman Robert Klein dismissed | | | | | | | | | | | | | | | | | | | | | | | | | Patterning osteogenesis by inducible gene expression in microfluidic culture systems. Integr Biol (Camb). 2010 Oct 5; Authors: Zhang Y, Gazit Z, Pelled G, Gazit D, Vunjak-Novakovic G The development of transitional interfacial zones between adjacent tissues remains a significant challenge for developing tissue engineering and regenerative medicine strategies. Using osteogenic differentiation as a model, we describe a novel approach to spatially regulate expression and secretion of the bone morphogenetic protein (BMP-2) in a two-dimensional field of cultured cells, by flow patterning the modulators of inducible BMP-2 gene expression. We first demonstrate control of gene expression, and of osteogenic differentiation of the cell line with inducible expression of BMP-2. Then we design laminar flow systems, with patterned delivery of Doxycycline (Dox), the expression modulator of BMP-2. The patterned concentration profiles were verified by computational simulation and dye separation experiments. Patterned differentiation experiments conducted in the flow systems for a period of three weeks showed the Dox concentration dependent osteogenic differentiation, as evidenced by mineral deposition. In summary, by combining inducible gene expression with laminar flow technologies, this study provided an innovative way to engineer tissue interfaces. PMID: 20924519 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell banking: between traceability and identifiability. Genome Med. 2010 Oct 5;2(10):73 Authors: Knoppers BM, Isasi R ABSTRACT: Stem cell banks are increasingly seen as an essential resource of biological materials for both basic and translational research. Stem cell banks support transnational access to quality-controlled and ethically sourced stem cell lines from different origins and of varying grades. According to the Organisation for Economic Co-operation and Development, advances in regenerative medicine are leading to the development of a bioeconomy, 'a world where biotechnology contributes to a significant share of economic output'. Consequently, stem cell banks are destined to constitute a pillar of the bioeconomy in many countries. While certain ethical and legal concerns are specific to the nature of stem cells, stem cell banking could do well to examine the approaches fostered by tissue banking generally. Indeed, the past decade has seen a move to simplify and harmonize biological tissue and data banking so as to foster international interoperability. In particular, the issues of consent and of traceability illustrate not only commonalities but the opportunity for stem cell banking to appreciate the lessons learned in biobanking generally. This paper analyzes convergence and divergence in issues surrounding policy harmonization, transnational sharing, informed consent, traceability and return of results in the context of stem cell banks. PMID: 20923580 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | Coming up in only three business days is a meeting of the Finance Subcommittee of the California stem cell agency, which is expected to act on a $600,000 proposal to create an online scientific journal and alter CIRM's fledgling loan program for biotech businesses.
No specifics are available, however, from CIRM's Web site, which makes it difficult for interested parties to comment thoughtfully. | | | | | | | | | |  | |  | |  |
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