|  |  |  | | | | | TE-RegenMed-StemCell feed | | | | | | | | | | | | | | | | | | | Clonal analysis of the proliferation potential of human bone marrow mesenchymal stem cells as a function of potency. Biotechnol Bioeng. 2011 May 2; Authors: Russell KC, Lacey MR, Gilliam JK, Tucker HA, Phinney DG, O'Connor KC Human mesenchymal stem cells (MSCs) from bone marrow are a heterogeneous ensemble of progenitors and lineage-committed cells, with a broad range of regenerative properties. Ex vivo expansion to produce sufficient quantities of MSCs is essential for most therapeutic applications. The present study resolves the relationship between proliferation potential of MSCs and their potency. Clonal analysis generated single-cell derived colonies of MSCs that were classified according to their trilineage potential to exhibit adipo- (A), chondro- (C) and osteogenesis (O) as a measure of potency. Multipotent OAC clones were highly proliferative with colony-forming efficiencies that ranged from 35% to 90%; whereas, O clones formed colonies with an efficiency of 5% or less (P < 0.01). Similar trends were evident during ex vivo expansion: for example, the median specific growth rate was 0.85 day(-1) (20 h doubling time) for cultures inoculated with OAC clones and was 5-fold less for inocula of O clones (P < 0.01). OA and OC clones had similar proliferation potentials. More than 75% of cells in subconfluent cultures inoculated with O clones stained positive for senescence-associated β-galactosidase activity vs. less than 10% for OAC clones (P < 0.001). Apoptotic cells were in the minority for all potency groups. Preliminary data generated during clonal analysis suggest that osteogenic potential of MSCs to produce mineralized matrix is a function of potency, as well. These results are discussed in the context of the preparation of efficacious MSC therapies by ex vivo expansion. Biotechnol. Bioeng. © 2011 Wiley Periodicals, Inc. PMID: 21538337 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Allogeneic Heart Valve Storage Above the Glass Transition at -80°C. Ann Thorac Surg. 2011 Apr 30; Authors: Brockbank KG, Wright GJ, Yao H, Greene ED, Chen ZZ, Schenke-Layland K BACKGROUND: Cryopreserved allogeneic heart valves are usually stored and transported below -135°C; however, such methods require expensive equipment for both storage and transportation. METHODS: In this study, vitrified porcine aortic valves were stored on either side of the cryoprotectant formulation's glass transition temperature (-119°C) at -80°C and -135°C, using a newly formulated vitrification solution (VS83) consisting of a combination of 4.65M dimethyl sulfoxide, 4.65M formamide, and 3.30M 1,2-propanediol. Three groups of valves were studied: (1) fresh; (2) VS83-preserved, stored at -80°C; and (3) VS83-preserved, stored at -135°C. RESULTS: Using the VS83 cryoprotectant concentration formulation, cracking was not observed during valve storage. No ice-related events were detectable during 5°C rewarming by differential scanning calorimetry. All cryopreserved tissue samples demonstrated significantly less viability than fresh samples (p < 0.01). No significant viability differences were observed between the VS83-preserved groups stored at -80°C and -135°C. Material testing did not reveal any significant differences among the three test groups. Multiphoton imaging of VS83-preserved heart valves stored at -80°C and -135°C demonstrated similar collagen and elastin structures. CONCLUSIONS: These results indicate that VS83-preserved heart valves can be stored and transported at temperatures in the vicinity of -80°C with retention of extracellular matrix integrity and material properties. The VS83 preservation of heart valves at -80°C without the need for liquid nitrogen should result in both decreased manufacturing costs and reduced employee safety hazards. Moreover, it is anticipated that low cell viability may result in less immunogenicity in vivo. PMID: 21536250 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Towards expansion of human hair follicle stem cells in vitro. Cell Prolif. 2011 Jun;44(3):244-53 Authors: Oh JH, Mohebi P, Farkas DL, Tajbakhsh J Objectives: Multipotential human hair follicle stem cells can differentiate into various cell lineages and thus are investigated here as potential autologous sources for regenerative medicine. Towards this end, we have attempted to expand these cells, directly isolated from minimal amounts of hair follicle explants, to numbers more suitable for stem-cell therapy. Materials and methods: Two types of human follicle stem cells, commercially available and directly isolated, were cultured using an in-house developed medium. The latter was obtained from bulge areas of hair follicles by mechanical and enzymatic dissociation, and was magnetically enriched for its CD200(+) fraction. Isolated cells were cultured for up to 4 weeks, on different supports: blank polystyrene, laminin- and Matrigel(TM) -coated surfaces. Results: Two-fold expansion was found, highlighting the slow-cycling nature of these cells. Flow cytometry characterization revealed: magnetic enrichment increased the proportion of CD200(+) cells from initially 43.3% (CD200+, CD34: 25.8%; CD200+, CD34+: 17.5%) to 78.2% (CD200+, CD34: 41.5%; CD200+, CD34+: 36.7%). Enriched cells seemed to have retained and passed on their morphological and molecular phenotypes to their progeny, as isolated CD200(+) presenting cells expanded in our medium to a population with 80% of cells being CD200(+) : 51.5% (CD200(+) , CD34(-) ) and 29.6% (CD200(+) , CD34(+) ). Conclusions: This study demonstrates the possibility of culturing human hair follicle stem cells without causing any significant changes to phenotypes of the cells. PMID: 21535265 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Maintenance of a functional hematopoietic stem cell niche through galactocerebrosidase and other enzymes. Curr Opin Hematol. 2011 Apr 30; Authors: Visigalli I, Biffi A PURPOSE OF REVIEW: The maintenance of a functional hematopoietic niche is critical for modulating the fate of hematopoietic stem cells (HSCs). Several enzymes were described as essential for guaranteeing niche functionality. This review summarizes the recent findings about the role of galactocerebrosidase and other enzymes involved in the maintenance of a functional HSC niche. RECENT FINDINGS: The essential role of enzymes actively involved in the maintenance of the bone marrow microenvironment, in bone remodeling, in regulating the sympathetic innervation of the niche, and in the production and relative balance of sphingolipids active in the niche has been recently highlighted. Enzymes involved in bone remodeling modify the cell-to-cell interaction between osteoblasts and HSCs. Heparanase, neutrophil elastase, and alpha-iduronidase affect the bioavailability of key cytokines and ligands within the extracellular matrix of the niche. Moreover, galactosyltransferase and galactocerebrosidase affect the function of the sympathetic nervous system and/or the balance of bioactive sphingolipids, thus influencing the SDF-1/CXCR4 axis and the proliferation of HSCs. SUMMARY: Here, we discuss the role of different enzymes directly or indirectly influencing the niche microenvironment, and we provide a comprehensive picture of their cooperative role, together with receptors, soluble factors, and the extracellular matrix, in maintaining a functional hematopoietic niche. PMID: 21537167 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recombinant soluble form of heparin-binding epidermal growth factor-like growth factor protein therapy drastically inhibits Fas-mediated fulminant hepatic failure: Implications in clinical application. Hepatol Res. 2011 Apr 28; Authors: Khai NC, Sakamoto K, Takamatsu H, Matsufuji H, Kosai KI PMID: 21535334 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | New hopes and strategies for the treatment of severe ocular surface disease. Curr Opin Ophthalmol. 2011 Jun 29; Authors: Nakamura T, Kinoshita S PURPOSE OF REVIEW: Severe ocular surface diseases (OSDs) are some of the most challenging entities facing the clinician today. This article aims to describe the recent advances and current development of ocular surface reconstruction from both basic science and clinical aspects. RECENT FINDINGS: To date, many candidate corneal epithelial stem or progenitor cell markers for culture grafts have been reported worldwide. Several groups have reported the long-term results of cultivated corneal and oral mucosal epithelial transplantation in severe OSD. In their attempt to further develop the system of ocular surface reconstruction, several groups recently reported using cells obtained from a novel origin, cell substrates, and safer culture procedures. SUMMARY: Autologous cultivated corneal limbal epithelial transplantation has been shown to be a well tolerated and promising treatment for patients with severe OSD. A newly developed transplantation technique using tissue-engineered epidermal adult stem cells, immature dental pulp stem cells, and hair follicle bulge-derived stem cells was reportedly successful for the reconstruction of corneal epithelium in an animal model of severe OSD. The recombinant human cross-linked collagen scaffold and a Food and Drug Administration-approved contact lens are also promising new techniques for successfully achieving ocular surface reconstruction. PMID: 21537182 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Sphingosine-1-phosphate signaling in vasculogenesis and angiogenesis. World J Biol Chem. 2010 Oct 26;1(10):291-7 Authors: Argraves KM, Wilkerson BA, Argraves WS Blood vessels either form de novo through the process of vasculogenesis or through angiogenesis that involves the sprouting and proliferation of endothelial cells in pre-existing blood vessels. A complex interactive network of signaling cascades downstream from at least three of the nine known G-protein-coupled sphingosine-1-phosphate (S1P) receptors act as a prime effector of neovascularization that occurs in embryonic development and in association with various pathologies. This review focuses on the current knowledge of the roles of S1P signaling in vasculogenesis and angiogenesis, with particular emphasis on vascular cell adhesion and motility responses. PMID: 21537462 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration. Braz Dent J. 2011;22(2):91-8 Authors: Estrela C, Alencar AH, Kitten GT, Vencio EF, Gava E In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer's disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration. PMID: 21537580 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Apparently "BRCA-Related" Breast and Ovarian Cancer Patient With Germline TP53 Mutation. Breast J. 2011 Apr 28; Authors: Janavičius R, Andrėkutė K, Mickys U, Rudaitis V, Brasiūnienė B, Griškevičius L Germline TP53 gene mutations are associated with complex cancer predisposition syndrome, the Li-Fraumeni syndrome, and are not as rare as were previously thought. Currently, the identification of Li-Fraumeni syndrome is mostly based on a conformance to descriptive criteria, which recently were amended to include wider spectrum of malignancies. The presence of very young age-onset breast cancers in TP53 mutations families is a feature that overlaps with hereditary breast/ovarian cancer families with BRCA1/2 genes mutations. Peri-diagnostic germline TP53 testing results in breast cancer patients can significantly affect surgical and adjuvant radiotherapy choices. The aim of this case report is to emphasize the importance of peri-diagnostic germline TP53 molecular testing in patients with early-onset breast cancer and its effect on the management and outcome of the disease. We present the apparent BRCA1-related, although mutation negative, breast and ovarian cancer patient who subsequently was confirmed to be TP53 c.817C>T (p.R273C) mutation carrier and discuss the importance of peri-diagnostic oncogenetic TP53 testing in early breast cancer cases. Histopathology and genetic modifiers (MDM2 SNP309G; TP53 R72P, PIN3) data are also addressed. PMID: 21535297 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Whole-cell based hybrid materials for green energy production, environmental remediation and smart cell-therapy. Chem Soc Rev. 2011 Feb;40(2):860-85 Authors: Léonard A, Dandoy P, Danloy E, Leroux G, Meunier CF, Rooke JC, Su BL This critical review highlights the advances that have been made over recent years in the domain of whole-cell immobilisation and encapsulation for applications relating to the environment and human health, particularly focusing on examples of photosynthetic plant cells, bacteria and algae as well as animal cells. Evidence that encapsulated photosynthetic cells remain active in terms of CO(2) sequestration and biotransformation (solar driven conversion of CO(2) into biofuels, drugs, fine chemicals etc.), coupled with the most recent advances made in the field of cell therapy, reveals the need to develop novel devices based on the preservation of living cells within abiotic porous frameworks. This review shall corroborate this statement by selecting precise examples that unambiguously demonstrate the necessity and the benefits of such smart materials. As will be described, the handling and exploitation of photosynthetic cells are enhanced by entrapment or encapsulation since the cells are physically separated from the liquid medium, thereby facilitating the recovery of the metabolites produced. In the case of animal cells, their encapsulation within a matrix is essential in order to create a physical barrier that can protect the cells auto-immune defenders upon implantation into a living body. For these two research axes, the key parameters that have to be kept in mind when designing hybrid materials will be identified, concentrating on essential aspects such as biocompatibility, mechanical strength and controlled porosity (264 references). PMID: 21212897 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Micro-/Nano-engineered Cellular Responses for Soft Tissue Engineering and Biomedical Applications. Small. 2011 Apr 28; Authors: Tay CY, Irvine SA, Boey FY, Tan LP, Venkatraman S The development of biomedical devices and reconstruction of functional ex vivo tissues often requires the need to fabricate biomimetic surfaces with features of sub-micrometer precision. This can be achieved with the advancements in micro-/nano-engineering techniques, allowing researchers to manipulate a plethora of cellular behaviors at the cell-biomaterial interface. Systematic studies conducted on these 2D engineered surfaces have unraveled numerous novel findings that can potentially be integrated as part of the design consideration for future 2D and 3D biomaterials and will no doubt greatly benefit tissue engineering. In this review, recent developments detailing the use of micro-/nano-engineering techniques to direct cellular orientation and function pertinent to soft tissue engineering will be highlighted. Particularly, this article aims to provide valuable insights into distinctive cell interactions and reactions to controlled surfaces, which can be exploited to understand the mechanisms of cell growth on micro-/nano-engineered interfaces, and to harness this knowledge to optimize the performance of 3D artificial soft tissue grafts and biomedical applications. PMID: 21538867 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chemically modified cellulose fibrous meshes for use as tissue engineering scaffolds. Bioorg Med Chem Lett. 2011 Apr 14; Authors: Filion TM, Kutikov A, Song J Cellulose and sulfated cellulose fibrous meshes exhibiting robust structural and mechanical integrity in water were fabricated using a combination of electrospinning, thermal-mechanical annealing and chemical modifications. The sulfated fibrous mesh exhibited higher retention capacity for human recombinant bone morphogenetic protein-2 than the cellulose mesh, and the retained proteins remained biologically active for at least 7 days. The sulfated fibrous mesh also more readily supported the attachment and osteogenic differentiation of rat bone marrow stromal cells in the absence of osteogenic growth factors. These properties combined make the sulfated cellulose fibrous mesh a promising bone tissue engineering scaffold. PMID: 21536439 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Recombinant human gelatin substitute with photoreactive properties for cell culture and tissue engineering. Biotechnol Bioeng. 2011 May 2; Authors: Kitajima T, Obuse S, Adachi T, Tomita M, Ito Y The human recombinant collagen I α1 chain monomer (rh-gelatin) was modified by the incorporation of an azidophenyl group to prepare photoreactive human gelatin (Az-rh-gelatin), with approximately 90% of the lysine residues conjugated with azidobenzoic acid. Slight changes in conformation (CD spectra) and thermal properties (gelation and melting points) were noticed after modification. Ultraviolet (UV) irradiation could immobilize the Az-rh-gelatin on polymer surfaces, such as polystyrene and polytetrafluoroethylene. Az-rh-gelatin was stably retained on the polymer surfaces, while unmodified gelatin was mostly lost by brief washing. Human mesenchymal cells grew more efficiently on the immobilized surface than on the coated surface. The immobilized Az-rh-gelatin on the polymer surfaces was able to capture engineered growth factors with collagen affinity, and the bound growth factors stimulated the growth of cells dose-dependently. It was also possible to immobilize Az-rh-gelatin in micropatterns (stripe, grid, and so on) using photomasks, and the cells grew according to the patterns. These results suggest that the photoreactive human gelatin, in combination with collagen-binding growth factors, will be clinically useful for surface modification of synthetic materials for cell culture systems and tissue engineering. Biotechnol. Bioeng. © 2011 Wiley Periodicals, Inc. PMID: 21538336 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Three-dimensional culture of human mesenchymal stem cells in a polyethylene terephthalate matrix. Biomed Mater. 2010 Dec;5(6):065013 Authors: Cao Y, Li D, Shang C, Yang ST, Wang J, Wang X Polyethylene terephthalate (PET) was used as the scaffold material to support the proliferation of human mesenchymal stem cells (hMSCs). The cells were cultured either statically in multi-wells or in a spinner flask agitated at 80 rpm for up to 20 days. To optimize the cell expansion condition, effects of the initial cell density and basic fibroblast growth factor (bFGF) were examined. During culture, cell growth and metabolism were tested. After 20 days, cells were harvested and surface markers were identified and quantified with flow cytometry. The results showed that hMSCs seeded at the lowest density gave the highest expansion fold. hMSCs grown in porous three-dimensional (3D) matrices displayed significantly different characteristics in terms of their proliferation and metabolism. PET matrices with 3D space could sustain cell proliferation for a long time. In addition, a low concentration (5 ng mL(-1)) of bFGF significantly enhanced the expansion of hMSCs in PET. Cell attachment and distribution in PET matrices were studied with confocal laser microscopy and scanning electron microscopy, which also confirmed cell proliferation. Furthermore, most of the cells in PET matrices were CD29, CD44 and CD105 positive, and CD34, CD45 and CD14 negative, confirming that hMSCs cultured in 3D PET matrices can be expanded and maintained in their undifferentiated state for at least 20 days without subculturing. PMID: 21079281 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Science Translational Medicine Podcast: 2 February 2011. Sci Transl Med. 2011 Feb 2;3(68):68pc2 Authors: Dahl S, Smith O PMID: 21370588 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cells in the dental tissues: perspectives for tissue regeneration. Braz Dent J. 2011;22(2):91-8 Authors: Estrela C, Alencar AH, Kitten GT, Vencio EF, Gava E In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that range from Alzheimer's disease to cardiac ischemia and regenerative medicine, like bone or tooth loss. Based on their ability to rescue and/or repair injured tissue and partially restore organ function, multiple types of stem/progenitor cells have been speculated. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental tissues are considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that these stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. In dentistry, stem cell biology and tissue engineering are of great interest since may provide an innovative for generation of clinical material and/or tissue regeneration. Mesenchymal stem cells were demonstrated in dental tissues, including dental pulp, periodontal ligament, dental papilla, and dental follicle. These stem cells can be isolated and grown under defined tissue culture conditions, and are potential cells for use in tissue engineering, including, dental tissue, nerves and bone regeneration. More recently, another source of stem cell has been successfully generated from human somatic cells into a pluripotent stage, the induced pluripotent stem cells (iPS cells), allowing creation of patient- and disease-specific stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental stem cell an attractive source of mesenchymal stem cells for tissue regeneration. This review describes new findings in the field of dental stem cell research and on their potential use in the tissue regeneration. PMID: 21537580 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Chitosan and its antimicrobial potential--a critical literature survey. Microb Biotechnol. 2009 Mar;2(2):186-201 Authors: Raafat D, Sahl HG Chitosan, an aminopolysaccharide biopolymer, has a unique chemical structure as a linear polycation with a high charge density, reactive hydroxyl and amino groups as well as extensive hydrogen bonding. It displays excellent biocompatibility, physical stability and processability. The term 'chitosan' describes a heterogeneous group of polymers combining a group of physicochemical and biological characteristics, which allow for a wide scope of applications that are both fascinating and as yet uncharted. The increased awareness of the potentials and industrial value of this biopolymer lead to its utilization in many applications of technical interest, and increasingly in the biomedical arena. Although not primarily used as an antimicrobial agent, its utility as an ingredient in both food and pharmaceutical formulations lately gained more interest, when a scientific understanding of at least some of the pharmacological activities of this versatile carbohydrate began to evolve. However, understanding the various factors that affect its antimicrobial activity has become a key issue for a better usage and a more efficient optimization of chitosan formulations. Moreover, the use of chitosan in antimicrobial systems should be based on sufficient knowledge of the complex mechanisms of its antimicrobial mode of action, which in turn would help to arrive at an appreciation of its entire antimicrobial potential. PMID: 21261913 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | An efficient technique for adjusting and maintaining specific hydration levels in soft biological tissues in vitro. Med Eng Phys. 2010 Sep;32(7):795-801 Authors: Shahmirzadi D, Hsieh AH Elucidating how mechanics is affected by hydration in soft biological tissues is critical for understanding the potential effects of diseases where tissue extracellular matrix (ECM) is altered. The ability to control ECM water content is necessary for studying hydration-dependent tissue mechanics and for minimizing confounding effects caused by differences in tissue water content among specimens. In this paper, we describe an approach to adjust and maintain water content using a two-stage hydration technique, in order to overcome unique challenges faced in mechanical testing of biological tissues. Bovine aortic tissue was selected to demonstrate the approach. A liquid phase approach using PEG solutions allowed for efficient initial adjustment of tissue hydration. This was followed by a vapor phase approach using a humidity chamber for maintaining stable water content for a defined test duration of 45 min. Incubation in PEG solution brought bovine aortic tissue samples to equilibrium water content in approximately 6 h, much more efficiently than using a humidity chamber alone. Characteristic relationships between tissue water content and PEG concentration as well as relative humidity were obtained. It was found that PEG concentrations ranging from 0 to 40% had an inverse relationship with tissue water content ranging from 80 to 380%, which corresponded to relative humidities between 53 and 99%. PMID: 20678998 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Ectopic study of tissue-engineered bone complex with enamel matrix proteins, bone marrow stromal cells in porous calcium phosphate cement scaffolds, in nude mice. Cell Prolif. 2011 Jun;44(3):274-282 Authors: Wang XJ, Huang H, Yang F, Xia LG, Zhang WJ, Jiang XQ, Zhang FQ Objective: This study aimed to investigate the potential of enamel matrix proteins (EMPs) on promoting osteogenic differentiation of porcine bone marrow stromal cells (pBMSCs), as well as new bone formation capabilities, in a tissue-engineered bone complex scaffold of EMPs, pBMSCs and porous calcium phosphate cement (CPC). Materials and methods: Effects of EMPs on pBMSCs in vitro was first determined by alkaline phosphatase (ALP) activity, von Kossa staining assay and mRNA expression of ALP, bone sialoprotein (BSP) and osteocalcin (OCN) genes. Next, an ectopic new bone formation test was performed in a nude mouse model with four groups: CPC scaffold alone; CPC scaffold + EMPs; CPC scaffold + pBMSCs; and CPC scaffold + EMPs + pBMSCs, for 2 or 4 weeks. Results: ALP activity, von Kossa assay and mRNA expressions of ALP, BSP and OCN genes were all significantly higher with 150 μg/ml EMP treatment in vitro. In nude mice, new bone formation was detected only in the CPC scaffold + EMPs + pBMSCs group at 2 weeks. At 4 weeks, in the tissue-engineered construct there was significantly higher bone formation ability than other groups. Conclusions: EMPs promoted osteogenic differentiation of pBMSCs, and the tissue-engineered complex of EMPs, pBMSCs and CPC scaffold may be a valuable alternative to be used in periodontal bone tissue engineering and regeneration. PMID: 21535268 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Multipotent stromal cells for autologous cell therapy approaches in the guinea pig model. ORL J Otorhinolaryngol Relat Spec. 2011;73(1):9-16 Authors: Frölich K, Scherzed A, Mlynski R, Technau A, Hagen R, Kleinsasser N, Radeloff A Multipotent stromal cells have become of increasing interest due to their potential to provide therapeutic approaches for autologous tissue repair. However, these cells are not well defined in the guinea pig, which represents an important model in hearing research. Adipose-tissue-derived stem cells (ADSC) and bone-marrow-derived stem cells (BMSC) were isolated from different donor sites, and growth curves were generated to judge the proliferation potential. Adipogenic, chondrogenic and osteogenic differentiation was induced and confirmed histologically. Finally, the capability of guinea pig ADSC to differentiate into neuron-like cells was investigated. With regard to the expansion potential, total cell number and doubling time, ADSC from the neck were the most suitable cells of the tested donor sites. Both ADSC and BMSC showed nearly identical behaviour and ability to undergo multilineage differentiation. Thus, we identified ADSC from the neck as a promising cell source for autologous cell-based approaches in hearing research using the guinea pig model. PMID: 20975314 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Towards expansion of human hair follicle stem cells in vitro. Cell Prolif. 2011 Jun;44(3):244-53 Authors: Oh JH, Mohebi P, Farkas DL, Tajbakhsh J Objectives: Multipotential human hair follicle stem cells can differentiate into various cell lineages and thus are investigated here as potential autologous sources for regenerative medicine. Towards this end, we have attempted to expand these cells, directly isolated from minimal amounts of hair follicle explants, to numbers more suitable for stem-cell therapy. Materials and methods: Two types of human follicle stem cells, commercially available and directly isolated, were cultured using an in-house developed medium. The latter was obtained from bulge areas of hair follicles by mechanical and enzymatic dissociation, and was magnetically enriched for its CD200(+) fraction. Isolated cells were cultured for up to 4 weeks, on different supports: blank polystyrene, laminin- and Matrigel(TM) -coated surfaces. Results: Two-fold expansion was found, highlighting the slow-cycling nature of these cells. Flow cytometry characterization revealed: magnetic enrichment increased the proportion of CD200(+) cells from initially 43.3% (CD200+, CD34: 25.8%; CD200+, CD34+: 17.5%) to 78.2% (CD200+, CD34: 41.5%; CD200+, CD34+: 36.7%). Enriched cells seemed to have retained and passed on their morphological and molecular phenotypes to their progeny, as isolated CD200(+) presenting cells expanded in our medium to a population with 80% of cells being CD200(+) : 51.5% (CD200(+) , CD34(-) ) and 29.6% (CD200(+) , CD34(+) ). Conclusions: This study demonstrates the possibility of culturing human hair follicle stem cells without causing any significant changes to phenotypes of the cells. PMID: 21535265 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Imaging Cardiac Stem Cell Therapy: Translations to Human Clinical Studies. J Cardiovasc Transl Res. 2011 May 3; Authors: Zhang WY, Ebert AD, Narula J, Wu JC Stem cell therapy promises to open exciting new options in the treatment of cardiovascular diseases. Although feasible and clinically safe, the in vivo behavior and integration of stem cell transplants still remain largely unknown. Thus, the development of innovative non-invasive imaging techniques capable of effectively tracking such therapy in vivo is vital for a more in-depth investigation into future clinical applications. Such imaging modalities will not only generate further insight into the mechanisms behind stem cell-based therapy, but also address some major concerns associated with translational cardiovascular stem cell therapy. In the present review, we summarize the principles underlying three major stem cell tracking methods: (1) radioactive labeling for positron emission tomography (PET) and single photon emission computed tomography (SPECT) imaging, (2) iron particle labeling for magnetic resonance imaging (MRI), and (3) reporter gene labeling for bioluminescence, fluorescence, MRI, SPECT, and PET imaging. We then discuss recent clinical studies that have utilized these modalities to gain biological insights into stem cell fate. PMID: 21538182 [PubMed - as supplied by publisher] | | | | | | | | | |  | |  | |  |
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