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| Inhibition of Proliferation and Differentiation of Mesenchymal Stem Cells by Carboxylated Carbon Nanotubes.
March 12, 2010 at 8:29 AM
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| | Inhibition of Proliferation and Differentiation of Mesenchymal Stem Cells by Carboxylated Carbon Nanotubes. ACS Nano. 2010 Mar 10; Authors: Liu D, Yi C, Zhang D, Zhang J, Yang M Multipotent mesenchymal stem cells (MSCs) have attracted substantial attention in stem cell therapy and tissue engineering due to their ability to be cultured for successive passages and multilineage differentiation. Carbon nanotubes (CNTs) have been proposed to be used as potential biomedical structures for bone formation. Therefore, it is important to study the mechanisms of interaction between MSCs and CNTs. We demonstrated that carboxylated single-walled carbon nanotubes (SWCNTs) and carboxylated multiwalled carbon nanotubes (MWCNTs) inhibited the proliferation, osteogenic differentiation, adipogenic differentiation, and mineralization of MSCs. Oxidative stress assay indicated that reactive oxygen species (ROS) may not be responsible for the observed cytotoxicity of carboxylated CNTs. Quantitative real-time polymerase chain reaction (Q-PCR) experiments confirmed that the expression of osteoblast specific genes and adipocyte differentiation specific genes was g! reatly attenuated during the differentiation of MSCs in the presence of carboxylated CNTs. TEM images revealed that CNTs might interact with proteins located on the cell membrane or in the cytoplasm, which have a further impact on subsequent cellular signaling pathways. Q-PCR results and Western blot analysis together verified that the inhibition of proliferation and osteogenic differentiation of MSCs may be modulated through a Smad-dependent bone morphogenetic protein (BMP) signaling pathway. PMID: 20218664 [PubMed - as supplied by publisher] | | |
| Probing Stemness and Neural Commitment in Human Amniotic Fluid Cells.
March 12, 2010 at 6:38 AM
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| | Probing Stemness and Neural Commitment in Human Amniotic Fluid Cells. Stem Cell Rev. 2010 Mar 11; Authors: Jezierski A, Gruslin A, Tremblay R, Ly D, Smith C, Turksen K, Sikorska M, Bani-Yaghoub M Recently, human amniotic fluid (AF) cells have attracted a great deal of attention as an alternative cell source for transplantation and tissue engineering. AF contains a variety of cell types derived from fetal tissues, of which a small percentage is believed to represent stem cell sub-population(s). In contrast to human embryonic stem (ES) cells, AF cells are not subject to extensive legal or ethical considerations; nor are they limited by lineage commitment characteristic of adult stem cells. However, to become therapeutically valuable, better protocols for the isolation of AF stem cell sub-populations need to be developed. This study was designed to examine the molecular components involved in self-renewal, neural commitment and differentiation of AF cells obtained at different gestational ages. Our results showed that, although morphologically heterogeneous, AF cells derived from early gestational periods ubiquitously expressed KERATIN 8 (K8), suggesting that! the majority of these cells may have an epithelial origin. In addition, AF cells expressed various components of NOTCH signaling (ligands, receptors and target genes), a pathway involved in stem cell maintenance, determination and differentiation. A sub-population of K8 positive cells (<10%) co-expressed NESTIN, a marker detected in the neuroepithelium, neural stem cells and neural progenitors. Throughout the gestational periods, a much smaller AF cell sub-population (<1%) expressed pluripotency markers, OCT4a, NANOG and SOX2, from which SOX2 positive AF cells could be isolated through single cell cloning. The SOX2 expressing AF clones showed the capacity to give rise to a neuron-like phenotype in culture, expressing neuronal markers such as MAP2, NFL and NSE. Taken together, our findings demonstrated the presence of fetal cells with stem cell characteristics in the amniotic fluid, highlighting the need for further research on their biology and clinical applications.! PMID: 20221716 [PubMed - as supplied by publisher] | | |
| High throughput assembly of spatially controlled 3D cell clusters on a micro/nanoplatform.
March 12, 2010 at 6:38 AM
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| | High throughput assembly of spatially controlled 3D cell clusters on a micro/nanoplatform. Lab Chip. 2010 Mar 21;10(6):775-82 Authors: Gallego-Perez D, Higuita-Castro N, Sharma S, Reen RK, Palmer AF, Gooch KJ, Lee LJ, Lannutti JJ, Hansford DJ Guided assembly of microscale tissue subunits (i.e. 3D cell clusters/aggregates) has found applications in cell therapy/tissue engineering, cell and developmental biology, and drug discovery. As cluster size and geometry are known to influence cellular responses, the ability to spatially control cluster formation in a high throughput manner could be advantageous for many biomedical applications. In this work, a micro- and nanofabricated platform was developed for this purpose, consisting of a soft-lithographically fabricated array of through-thickness microwells structurally bonded to a sheet of electrospun fibers. The microwells and fibers were manufactured from several polymers of biomedical interest. Human hepatocytes were used as model cells to demonstrate the ability of the platform to allow controlled cluster formation. In addition, the ability of the device to support studies on semi-controlled heterotypic interactions was demonstrated by co-culturing hepat! ocytes and fibroblasts. Preliminary experiments with other cells of interest (pancreatic cells, embryonic stem cells, and cardiomyocytes) were also conducted. Our platform possesses several advantages over previously developed microwell arrays: a more in vivo-like topographical stimulation of cells; better nutrient/waste exchange through the underlying nanofiber mat; and easy integration into standard two-chamber cell culture well systems. PMID: 20221567 [PubMed - in process] | | |
| Regulation of Human Adipose-Derived Stromal Cell Osteogenic Differentiation by Insulin-like Growth Factor-1 and Platelet-Derived Growth Factor-Alpha.
March 12, 2010 at 6:38 AM
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| | Regulation of Human Adipose-Derived Stromal Cell Osteogenic Differentiation by Insulin-like Growth Factor-1 and Platelet-Derived Growth Factor-Alpha. Plast Reconstr Surg. 2010 Mar 8; Authors: Levi B, James AW, Wan DC, Glotzbach JP, Commons GW, Longaker MT INTRODUTION:: Human adipose-derived stromal cells (hASCs) possess a great potential for tissue engineering purposes. Our laboratory is interested in harnessing hASCs for skeletal tissue regeneration and identifying those factors that enhance hASC osteogenic differentiation. We hypothesized that Insulin-Like Growth Factor (IGF) and Platelet Derived Growth Factor (PDGF) would stimulate hASC osteogenesis and that IGF would stimulate adipogenesis. MATERIALS AND METHODS:: ASCs were harvested from human lipoaspirate. Previously, a microarray analysis examined gene expression throughout osteogenic differentiation. In a candidate fashion we added recombinant Insulin-Like Growth Factor (IGF-1) and Platelet-Derived Growth Factor (PDGF)-alpha individually as well as in combination. Osteogenesis and adipogenesis were assessed by alkaline phosphatase, Alizarin red, and Oil red O staining, as well as qRT-PCR (RUNX2, ALP, OCN, IGF1, PPARG, LPL, AP2, GCP1). Finally, intersection ! between IGF and PDGF signaling pathways was evaluated. RESULTS:: IGF-1 was observed to increase osteogenic differentiation by all markers (*p<0.01). However, PDGF-alpha when added alone primarily did not effect osteogenic markers. PDGF-alpha positively regulated transcription of IGF1. Addition of PDGF-alpha in combination with or prior to IGF-1 enhanced osteogenesis more than either alone. IGF-1 increased while PDGF-alpha diminished hASC adipogenesis. CONCLUSION:: IGF signaling significantly increased osteogenesis in human ASCs and may be used for tissue engineering purposes. The combination of PDGF and IGF may be more beneficial than either alone in driving ASC osteogenesis. Future in vivo applications will focus on the combination of ASCs, biomimetic scaffolds and recombinant IGF. PMID: 20220555 [PubMed - as supplied by publisher] | | |
| Migration of Marrow Stromal Cells in Response to Sustained Release of Stromal-Derived Factor-1alpha from Poly(lactide ethylene oxide fumarate) Hydrogels.
March 12, 2010 at 6:38 AM
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| | Migration of Marrow Stromal Cells in Response to Sustained Release of Stromal-Derived Factor-1alpha from Poly(lactide ethylene oxide fumarate) Hydrogels. Int J Pharm. 2010 Feb 25; Authors: He X, Ma J, Jabbari E Stromal derived factor-1alpha (SDF-1alpha) is an important chemokine in stem cell trafficking and plays a critical role in the homing of bone marrow stromal (BMS) cells. However, its use in tissue regeneration is limited by its relatively short half-life and the time-dependent nature of cell homing to the site of injury. The objective of this work was to investigate the release characteristics of SDF-1alpha from degradable poly (lactide ethylene oxide fumarate) (PLEOF) hydrogels and to determine the effect of sustained release of SDF-1alpha on migration of BMS cells. Three PLEOF hydrogels with poly(L-lactide) (PLA) fractions of 6, 9, and 24% by weight were synthesized. After the addition of chemokine, the polymerizing mixture was crosslinked to produce SDF-1alpha loaded PLEOF hydrogels. The hydrogels were characterized with respect to sol fraction, water uptake, degradation, SDF-1alpha loading efficiency and release kinetics, and migration rate of bone marrow stro! mal (BMS) cells. The more hydrophilic hydrogels with 6 and 9% PLA fraction had a pronounced burst release followed by a period of sustained release by diffusion for 21 days. The more hydrophobic hydrogel with 24% PLA fraction had a less pronounced burst release and displayed a slow but constant release by diffusion between days 1-9 followed by a fast release by diffusion-degradation from days 9 to 18. The fraction of active SDF-1alpha released from 6, 9, and 24% hydrogels after 21 days was 34.3, 32.3, and 35.8%, respectively. The migration of BMS cells in response to time-released SDF-1alpha closely followed the protein release kinetics from the hydrogels. The biodegradable PLEOF hydrogel may potentially be useful as a delivery matrix for sustained release of SDF-1alpha in the proliferative phase of healing for recruitment of progenitor cells in tissue engineering applications. PMID: 20219655 [PubMed - as supplied by publisher] | | |
| A comparison of the influence of material on in vitro cartilage tissue engineering with PCL, PGS, and POC 3D scaffold architecture seeded with chondrocytes.
March 12, 2010 at 6:38 AM
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| | A comparison of the influence of material on in vitro cartilage tissue engineering with PCL, PGS, and POC 3D scaffold architecture seeded with chondrocytes. Biomaterials. 2010 Mar 8; Authors: Jeong CG, Hollister SJ The goal of this study was to determine material effects on cartilage regeneration for scaffolds with the same controlled architecture. The 3D polycaprolactone (PCL), poly (glycerol sebacate) (PGS), and poly (1,8 octanediol-co-citrate) (POC) scaffolds of the same design were physically characterized and tissue regeneration in terms of cell phenotype, cellular proliferation and differentiation, and matrix production were compared to find which material would be most optimal for cartilage regeneration in vitro. POC provided the best support for cartilage regeneration in terms of tissue ingrowth, matrix production, and relative mRNA expressions for chondrocyte differentiation (Col2/Col1). PGS was seen as the least favorable material for cartilage based on its relatively high de-differentiation (Col1), hypertrophic mRNA expression (Col10) and high matrix degradation (MMP13, MMP3) results. PCL still provided microenvironments suitable for cells to be active yet it seem! ed to cause de-differentiation (Col1) of chondrocytes inside the scaffold while many cells migrated out, growing cartilage outside the scaffold. PMID: 20219243 [PubMed - as supplied by publisher] | | |
| Collagen matrix physical properties modulate endothelial colony forming cell derived vessels in vivo.
March 12, 2010 at 6:38 AM
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| | Collagen matrix physical properties modulate endothelial colony forming cell derived vessels in vivo. Microvasc Res. 2010 Mar 7; Authors: Critser PJ, Kreger ST, Voytik-Harbin SL, Yoder MC Developing tissue engineering approaches to generate functional vascular networks is important for improving treatments of peripheral and cardiovascular disease. Endothelial colony forming cells (ECFCs) are an endothelial progenitor cell (EPC) population defined by high proliferative potential and an ability to vascularize collagen-based matrices in vivo. Little is known regarding how physical properties of the local cell microenvironment guide vessel formation following EPC transplantation. In vitro evidence suggests that collagen matrix stiffness may modulate EPC vessel formation. The present study determined the ability of 3D collagen matrix physical properties, varied by changing collagen concentration, to influence ECFC vasculogenesis in vivo. Human umbilical cord blood ECFCs were cultured within matrices for 18h in vitro and then fixed for in vitro analysis or implanted subcutaneously into the flank of immunodeficient mice for 14days. We report that increasi! ng collagen concentration significantly decreased ECFC derived vessels per area (density), but significantly increased vessel sizes (total cross sectional area). These results demonstrate that the physical properties of collagen matrices influence ECFC vasculogenesis in vivo and that by modulating these properties, one can guide vascularization. PMID: 20219180 [PubMed - as supplied by publisher] | | |
| Serum-free medium with osteogenic supplements induces adipogenesis in rat bone marrow stromal cells.
March 12, 2010 at 6:38 AM
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| | Serum-free medium with osteogenic supplements induces adipogenesis in rat bone marrow stromal cells. Cell Biol Int. 2010 Mar 10; Authors: Ichikawa J Adult bone marrow stromal cells (BMSCs) contain mesenchymal stem cells (MSCs). MSCs can differentiate into osteoblasts, chondrocytes, adipocytes, and myoblasts, and are thus considered useful in tissue engineering for therapeutic and clinical purposes. Fetal calf serum (FCS) is usually included in the differentiation medium, but the clinical application of FCS may pose a problem for some patients. To improve the efficiency and safety of BMSC cultivation, the effect of serum-free conditions on the osteogenic differentiation of rat BMSCs was examined. In the presence of 10% FCS and osteogenic supplements, the cells formed mineralized von Kossa-positive deposits. Under serum-free conditions with osteogenic supplementation, however, the cells possessed cytosolic lipid vacuoles that could be stained with Oil Red O. The mRNA expression of peroxisome proliferator-activated receptor gamma (PPAR gamma), an adipogenic marker, increased under the serum-free condition with os! teogenic supplements. These data indicate that rat BMSCs differentiate into adipocytes under serum-free conditions even with osteogenic supplementation, and that FCS is needed to induce proper osteogenic differentiation in rat BMSCs. PMID: 20218971 [PubMed - as supplied by publisher] | | |
| Potential therapeutic applications of muscle-derived mesenchymal stem and progenitor cells.
March 12, 2010 at 6:38 AM
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| | Potential therapeutic applications of muscle-derived mesenchymal stem and progenitor cells. Expert Opin Biol Ther. 2010 Apr;10(4):505-17 Authors: Jackson WM, Nesti LJ, Tuan RS Importance of the field: Mesenchymal adult stem cells have properties that make them attractive for use in tissue engineering and regenerative medicine. They are inherently plastic, enabling them to differentiate along different lineages, and promote wound healing and regeneration of surrounding tissues by modulating immune and inflammatory responses, promoting angiogenesis and secreting other trophic factors. Unlike embryonic stem cells, clinical uses of mesenchymal stem cells are not encumbered by ethical considerations or legal restrictions. Areas covered in this review: We discuss skeletal muscle as a source of mesenchymal stem and progenitor cells by reviewing their biology and current applications in tissue engineering and regenerative medicine. This paper covers literature from the last 5 - 10 years. What the reader will gain: Skeletal muscle is a plentiful source of mesenchymal stem and progenitor cells. This tissue may be obtained via routine biopsy or co! llection after surgical debridement. We describe the biology of these cells and provide an overview of therapeutic applications currently being developed to take advantage of their regenerative properties. Take home message: There is potential for stem and progenitor cells derived from skeletal muscle to be incorporated in clinical interventions, either as a cellular therapy to modify the natural history of disease or as a component of engineered tissue constructs that can replace diseased or damaged tissues. PMID: 20218920 [PubMed - in process] | | |
| Fabrication of 3D Cell Constructs Using Temperature-responsive Hydrogel.
March 12, 2010 at 6:38 AM
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| | Fabrication of 3D Cell Constructs Using Temperature-responsive Hydrogel. Tissue Eng Part A. 2010 Mar 10; Authors: Sasaki JI, Asoh TA, Matsumoto T, Egusa H, Sohmura T, Alsberg E, Akashi M, Yatani H A morphologically controlled three-dimensional (3D) cell construct composed of only cells and having no scaffold material might be a valuable biologic material for tissue engineering applications, as the scaffold materials can cause delay of tissue regeneration in some conditions. To obtain such a 3D cell construct, a 3D thermoresponsive hydrogel (pNIPAAm) was prepared as a mold material that changes its volume depending on the temperature. 3D osteoblast cell constructs with a variety of morphologies as well as a mono-layered cell sheet were obtained by decreasing the surrounding temperature of the hydrogel designed with a predefined shape and formed by curing in a polymer mold manufactured via 3D printing. The cell sheet or 3D cell constructs detachment resulted from a simple change in the gel volume, not by the surface chemistry of the gel, because the surface hydrophilicity of the gel was maintained over a wide temperature range. These 2D/3D cell constructs hav! e numbers of exciting applications such as cell carriers for tissue regeneration or as model tissues for the biological study. PMID: 20218862 [PubMed - as supplied by publisher] | | |
| Non-invasive imaging of bone specific collagen I expression in a luciferase transgenic mouse model.
March 12, 2010 at 6:38 AM
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| | Non-invasive imaging of bone specific collagen I expression in a luciferase transgenic mouse model. Tissue Eng Part C Methods. 2010 Mar 10; Authors: Liu J, Arends R, Martens AC, den Brok-Bardoel MH, Scheepers MG, van Blitterswijk C, De Boer J Luciferase transgenic mice are a very promising tool for non-invasive, quantitative and longitudinal evaluation of gene expression. The aim of this study was to validate the Col I-Luc transgenic mouse model in which the luciferase gene is driven by bone specific regulatory elements from the mouse collagen alpha (1) I gene for bioluminescent imaging (BLI) of bone development and remodelling. We observed strong luciferase activity in skeletal tissues of Col(I)-Luc mice, and observed that the light intensity declined with postnatal bone development. Luciferase activity was enhanced in a tail bone repair model and we were able to monitor the process of ectopic bone formation induced by recombinant human bone morphogenetic protein 2 using BLI. We conclude that Col(I)-Luc transgenic mice can be applied in the field of bone tissue engineering for monitoring bone repair processes and to investigate osteoinductive molecules or scaffolds. PMID: 20218816 [PubMed - as supplied by publisher] | | |
| Inhibition of Proliferation and Differentiation of Mesenchymal Stem Cells by Carboxylated Carbon Nanotubes.
March 12, 2010 at 6:38 AM
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| | Inhibition of Proliferation and Differentiation of Mesenchymal Stem Cells by Carboxylated Carbon Nanotubes. ACS Nano. 2010 Mar 10; Authors: Liu D, Yi C, Zhang D, Zhang J, Yang M Multipotent mesenchymal stem cells (MSCs) have attracted substantial attention in stem cell therapy and tissue engineering due to their ability to be cultured for successive passages and multilineage differentiation. Carbon nanotubes (CNTs) have been proposed to be used as potential biomedical structures for bone formation. Therefore, it is important to study the mechanisms of interaction between MSCs and CNTs. We demonstrated that carboxylated single-walled carbon nanotubes (SWCNTs) and carboxylated multiwalled carbon nanotubes (MWCNTs) inhibited the proliferation, osteogenic differentiation, adipogenic differentiation, and mineralization of MSCs. Oxidative stress assay indicated that reactive oxygen species (ROS) may not be responsible for the observed cytotoxicity of carboxylated CNTs. Quantitative real-time polymerase chain reaction (Q-PCR) experiments confirmed that the expression of osteoblast specific genes and adipocyte differentiation specific genes was g! reatly attenuated during the differentiation of MSCs in the presence of carboxylated CNTs. TEM images revealed that CNTs might interact with proteins located on the cell membrane or in the cytoplasm, which have a further impact on subsequent cellular signaling pathways. Q-PCR results and Western blot analysis together verified that the inhibition of proliferation and osteogenic differentiation of MSCs may be modulated through a Smad-dependent bone morphogenetic protein (BMP) signaling pathway. PMID: 20218664 [PubMed - as supplied by publisher] | | |
| Current world literature.
March 12, 2010 at 6:38 AM
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| | Current world literature. Curr Opin Organ Transplant. 2010 Feb;15(1):131-46 Authors: PMID: 20071990 [PubMed - indexed for MEDLINE] | | |
| Technological advances in renal replacement therapy: five years and beyond.
March 12, 2010 at 6:38 AM
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| | Technological advances in renal replacement therapy: five years and beyond. Clin J Am Soc Nephrol. 2009 Dec;4 Suppl 1:S132-6 Authors: Rastogi A, Nissenson AR The worldwide epidemic of chronic kidney disease shows no signs of abating in the near future. Current dialysis forms of renal replacement therapy (RRT), even though successful in sustaining life and improving quality of life somewhat for patients with ESRD, have many limitations that result in still unacceptably high morbidity and mortality. Transplantation is an excellent option but is limited by the scarcity of organs. An ideal form of RRT would mimic the functions of natural kidneys and be transparent to the patient, as well as affordable to society. Recent advances in technology, although generally in early stages of development, might achieve these goals. The application of nanotechnology, microfluidics, bioreactors with kidney cells, and miniaturized sorbent systems to regenerate dialysate makes clinical reality seem closer than ever before. Finally, stem cells hold much promise, both for kidney disease and as a source of tissues and organs. In summary, nep! hrology is at an exciting crossroad with the application of innovative and novel technologies to RRT that hold considerable promise for the near future. PMID: 19995997 [PubMed - indexed for MEDLINE] | | |
| Nanotechnology in the design of soft tissue scaffolds: innovations in structure and function.
March 12, 2010 at 6:38 AM
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| | Nanotechnology in the design of soft tissue scaffolds: innovations in structure and function. Wiley Interdiscip Rev Nanomed Nanobiotechnol. 2010 Jan;2(1):20-34 Authors: Ayres CE, Jha BS, Sell SA, Bowlin GL, Simpson DG Engineered scaffolds function to supplement or replace injured, missing, or compromised tissue or organs. The current direction in this research area is to create scaffolds that mimic the structure and function of the native extracellular matrix (ECM). It is believed that the fabrication of a scaffold that has both structural integrity and allows for normal cellular function and interaction will bring scaffolds closer to clinical relevance. Nanotechnology innovations have aided in the development of techniques for the production of nanofiber scaffolds. The three major processing techniques, self-assembly, phase separation, and electrospinning, produce fibers that rival the size of those found in the native ECM. However, the simplicity, versatility, and scalability of electrospinning make it an attractive processing method that can be used to reproduce aspects of the complexity that characterizes the native ECM. Novel electrospinning strategies include alterations ! of scaffold composition and architecture, along with the addition and encapsulation of cells, pharmaceuticals and growth factors within the scaffold. This article reviews the major nanofiber fabrication technologies as well as delves into recent significant contributions to the conception of a meaningful and practical electrospun scaffold. PMID: 20049828 [PubMed - indexed for MEDLINE] | | |
| Therapeutic potential of adipose-derived stem cells in vascular growth and tissue repair.
March 12, 2010 at 6:38 AM
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| | Therapeutic potential of adipose-derived stem cells in vascular growth and tissue repair. Curr Opin Organ Transplant. 2010 Feb;15(1):86-91 Authors: Hong SJ, Traktuev DO, March KL PURPOSE OF REVIEW: Adipose-derived stem cells (ASCs) are readily available from autologous adipose tissue and have been demonstrated to provide significant potential for tissue rescue from, or repair of, damage in multiple animal models. These include models of myocardial infarction, heart failure, hind limb ischemia, and inflammatory conditions. Early clinical studies have now extended testing of the effects of ASC into patients. This review highlights some of the key reports underlining the potential of ASCs, focusing particularly on diseases involving the cardiovascular system, vascular growth, and tissue repair. RECENT FINDINGS: Clinical applications of ASCs have begun to show early safety results and promising possibility of efficacy in patients with a range of diseases, including acute myocardial infarction, peripheral vascular disease, and soft and bony tissue defects including cranial bone loss, Crohn's-related fistula, and skin wounds. These effects are i! mportantly based on the secretion of trophic and survival factors by these cells and by their participations in the growth and remodeling of blood vessels. These results suggest that ASCs could be a valuable therapeutic option in vascular growth and tissue repair in various clinical settings. SUMMARY: ASCs may ultimately represent a valuable therapeutic option in tissue rescue and repair based on their ready availability, proangiogenesis and antiapoptotic factor secretion, immunomodulatory effects, and capacity for multilineage differentiation and ready expansion. PMID: 19949335 [PubMed - indexed for MEDLINE] | | |
| Prospects for osteoprogenitor stem cells in fracture repair and osteoporosis.
March 12, 2010 at 6:38 AM
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| | Prospects for osteoprogenitor stem cells in fracture repair and osteoporosis. Curr Opin Organ Transplant. 2010 Feb;15(1):73-8 Authors: Clines GA PURPOSE OF REVIEW: Bone regeneration and fracture repair are the complex processes of mesenchymal stem cell invasion, chondrogenesis, osteogenesis and angiogenesis. The coordinated actions of these principal processes result in the reconstruction of a normal bone and restoration of a structural unit. However, these normal bone regenerative mechanisms breakdown during fracture repair failure and postmenopausal osteoporosis. RECENT FINDINGS: Recent discoveries of circulating multipotent stem cells with mixed characteristics of endothelial cell and osteogenic capacity have raised interest in new and potentially breakthrough therapies for fracture and pathologic bone loss. The cooperative actions of other mesenchymal stem cell lineage such as adipocytes and processes such as angiogenesis in bone repair could also serve as novel therapeutic targets. Recent data suggest that anabolic parathyroid hormone therapy, already approved for the treatment of osteoporosis, may re! cruit osteoprogenitor cells and also have a role in fracture repair. SUMMARY: The present review will highlight recent information on stem cells and bone repair and examine potential avenues for future research. PMID: 19935065 [PubMed - indexed for MEDLINE] | | |
| Regenerating pancreatic beta-cells: plasticity of adult pancreatic cells and the feasibility of in-vivo neogenesis.
March 12, 2010 at 6:38 AM
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| | Regenerating pancreatic beta-cells: plasticity of adult pancreatic cells and the feasibility of in-vivo neogenesis. Curr Opin Organ Transplant. 2010 Feb;15(1):79-85 Authors: Juhl K, Bonner-Weir S, Sharma A PURPOSE OF REVIEW: Diabetes results from inadequate functional mass of pancreatic beta-cells and therefore replenishing with new glucose-responsive beta-cells is an important therapeutic option. In addition to replication of pre-existing beta-cells, new beta-cells can be produced from differentiated adult cells using in-vitro or in-vivo approaches. This review will summarize recent advances in in-vivo generation of beta-cells from cells that are not beta-cells (neogenesis) and discuss ways to overcome the limitations of this process. RECENT FINDINGS: Multiple groups have shown that adult pancreatic ducts, acinar and even endocrine cells exhibit cellular plasticity and can differentiate into beta-cells in vivo. Several different approaches, including misexpression of transcription factors and tissue injury, have induced neogenesis of insulin-expressing cells in vivo and ameliorated diabetes. SUMMARY: Recent breakthroughs demonstrating cellular plasticity of adult p! ancreatic cells to form new beta-cells are a positive first step towards developing in-vivo regeneration-based therapy for diabetes. Currently, neogenesis processes are inefficient and do not generate sufficient amounts of beta-cells required to normalize hyperglycemia. However, an improved understanding of mechanisms regulating neogenesis of beta-cells from adult pancreatic cells and of their maturation into functional glucose-responsive beta-cells can make therapies based on in-vivo regeneration a reality. PMID: 19907327 [PubMed - indexed for MEDLINE] | | |
| Inducible pluripotent stem cells: not quite ready for prime time?
March 12, 2010 at 6:38 AM
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| | Inducible pluripotent stem cells: not quite ready for prime time? Curr Opin Organ Transplant. 2010 Feb;15(1):61-7 Authors: Robbins RD, Prasain N, Maier BF, Yoder MC, Mirmira RG PURPOSE OF REVIEW: Inducible pluripotent stem (iPS) cells derived from somatic cells represent a novel renewable source of tissue precursors. The potential of iPS cells is considered to be at least equivalent to that of human embryonic stem cells, facilitating the treatment or cure of diseases such as diabetes mellitus, spinal cord injuries, cardiovascular disease, and neurodegenerative diseases, but with the potential added benefit of evading the adaptive immune response that otherwise limits allogeneic cell-based therapies. This review discusses recent advances in pluripotency induction and the use of iPS cells to produce differentiated cells, while highlighting roadblocks to the widespread use of this technology in the clinical arena. RECENT FINDINGS: Whereas ethical and safety issues surrounding the use of human embryonic stem cells for the treatment of disease continue to be debated, use of iPS cells may be viewed as a more widely acceptable compromise. Since! the first descriptions of inducible pluripotency from somatic cells, multiple laboratories have collectively made tremendous strides both in developing alternative, more clinically acceptable, induction strategies and in demonstrating the proof-of-principle that iPS cells can be differentiated into a variety of cell types to reverse mouse models of human disease. SUMMARY: Although the prospect of using patient-specific iPS cells has much appeal from an ethical and immunologic perspective, the limitations of the technology from the standpoint of reprogramming efficiency and therapeutic safety necessitate much more in-depth research before the initiation of human clinical trials. PMID: 19855280 [PubMed - indexed for MEDLINE] | | |
| c-MYC independent nuclear reprogramming favors cardiogenic potential of induced pluripotent stem cells.
March 12, 2010 at 6:16 AM
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| | c-MYC independent nuclear reprogramming favors cardiogenic potential of induced pluripotent stem cells. J Cardiovasc Transl Res. 2010 Feb 1;3(1):13-23 Authors: Martinez-Fernandez A, Nelson TJ, Ikeda Y, Terzic A Induced pluripotent stem cell (iPS) technology has launched a new platform in regenerative medicine aimed at deriving unlimited replacement tissue from autologous sources through somatic cell reprogramming using stemness factor sets. In this way, authentic cardiomyocytes have been obtained from iPS and recently demonstrated in proof-of-principle studies to repair infarcted heart. Optimizing the cardiogenic potential of iPS progeny would ensure a maximized yield of bioengineered cardiac tissue. Here, we reprogrammed fibroblasts in the presence or absence of c-MYC to determine if the acquired cardiogenicity is sensitive to the method of nuclear reprogramming. Using lentiviral constructs that expressed stemness factors SOX2, OCT4, and KLF4 with or without c-MYC, iPS clones generated through fibroblast reprogramming demonstrated indistinguishable characteristics for 5 days of differentiation with similar cell morphology, growth rates, and chimeric embryo integration. ! However, 4-factor c-MYC dependent nuclear reprogramming produced iPS progeny that consistently prolonged the expression of pluripotent Oct-4 and Fgf4 genes and repressed cardiac differentiation. In contrast, 3-factor c-MYC-less iPS clones efficiently up-regulated pre-cardiac (CXCR4, Flk-1, and Mesp1/2) and cardiac (Nkx2.5, Mef2c, and Myocardin) gene expression patterns. In fact, 3-factor iPS progeny demonstrated early and robust cardiogenesis during in vitro differentiation with consistent beating activity, sarcomere maturation, and rhythmical intracellular calcium dynamics. Thus, nuclear reprogramming independent of c-MYC enhances production of pluripotent stem cells with innate cardiogenic potential. PMID: 20221419 [PubMed - as supplied by publisher] | | |
| Differentiation and migration properties of human fetal umbilical cord perivascular cells: potential for lung repair.
March 12, 2010 at 6:16 AM
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| | Differentiation and migration properties of human fetal umbilical cord perivascular cells: potential for lung repair. J Cell Mol Med. 2010 Mar 9; Authors: Montemurro T, Andriolo G, Montelatici E, Weissmann G, Crisan M, Colnaghi MR, Rebulla P, Mosca F, Péault B, Lazzari L Mesenchymal stem cells (MSC) have been derived from different cultured human tissues, including bone marrow, adipose tissue, amniotic fluid and umbilical cord blood. Only recently was a descendance of MSC from perivascular cells (PC) hypothesized, the latter being defined as CD146+ NG2+ PDGF-Rbeta+ ALP+ CD34- CD45- vWF- CD144-. Herein we studied the properties of PC from a novel source, the fetal human umbilical cord (HUC) collected from pre-term newborns. By immunohistochemistry and flow cytometry we show that pre-term/fetal HUC contain more PC than their full-term counterparts (2.5% versus 0.15%). Moreover, fetal HUCPC express the embryonic cell markers SSEA4, Runx1 and Oct-4 and can be cultured over the long term. To further confirm the MSC identity of these cultured PC, we also showed their expression at different passages of antigens that typify MSC. The multilineage differentiative capacity of HUCPC into osteogenic, adipogenic and myogenic cell lineages was ! demonstrated in culture. In the perspective of a therapeutic application in chronic lung disease of pre-term newborns, we demonstrated the in vitro ability of HUCPC to migrate towards an alveolar type II cell line damaged with bleomycin, an anti-cancer agent with known pulmonary toxicity. The secretory profile exhibited by fetal HUCPC in the migration assay suggested a paracrine effect that could be exploited in various clinical conditions including lung disorders. PMID: 20219017 [PubMed - as supplied by publisher] | | |
| Type-specific dysregulation of matrix metalloproteinases and their tissue inhibitors in end-stage heart failure patients.
March 12, 2010 at 6:16 AM
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| | Type-specific dysregulation of matrix metalloproteinases and their tissue inhibitors in end-stage heart failure patients. J Cell Mol Med. 2010 Mar 9; Authors: Wei Y, Cui C, Lainscak M, Zhang X, Li J, Huang J, Zhang H, Zheng Z, Hu S Although past studies observed the changes of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in end-stage heart failure (HF) patients, a consistent and clear pattern of type-specific MMPs and/or TIMPs has yet to be further defined. In this study, proteomic approach of human protein antibody arrays was used to compare MMP and TIMP expression levels of left ventricular (LV) myocardial samples from end-stage HF patients due to dilated cardiomyopathy (DCM) with those from age- and sex- matched non-failing subjects. Western blot analysis, immunohistochemistry, and enzyme-linked immunosorbent assay (ELISA) were used for validation of our results. We observed that MMP-10 and -7 abundance increased, accompanied by decreased TIMP-4 in DCM failing hearts (n=8) compared with non-failing hearts (n=8). The results were further validated in a cohort of 34 end-stage HF patients derived from three forms of cardiomyopathies. Cardiac and plasma! MMP-10 levels were positively correlated with the LV end-diastolic dimension (LVEDD) in this HF cohort. In addition, we observed that insulin-like growth facter-2 (IGF-2) promoted MMP-10 production in neonatal rat cardiomyocytes. In conclusion, this study demonstrated a selective upregulation of MMP-10 and -7 along with a discordant change of TIMP-4, and a positive correlation between MMP-10 levels and the degree of LV dilation in end-stage HF patients. Our findings suggest that type-specific dysregulation of MMPs and TIMPs is associated with LV remodeling in end-stage HF patients, and MMP-10 may act as a novel biomarker for LV remodeling. PMID: 20219015 [PubMed - as supplied by publisher] | | |
| Fetal and adult cardiomyocyte progenitor cells have different developmental potential.
March 12, 2010 at 6:16 AM
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| | Fetal and adult cardiomyocyte progenitor cells have different developmental potential. J Cell Mol Med. 2010 Mar 8; Authors: van Vliet P, Smits AM, de Boer TP, Korfage TH, Metz CH, Roccio M, van der Heyden MA, van Veen TA, Sluijter JP, Doevendans PA, Goumans MJ In the past years, cardiovascular progenitor cells have been isolated from the human heart and characterized. Up to date, no studies have been reported in which the developmental potential of fetal and adult cardiovascular progenitors was tested simultaneously. However, intrinsic differences will likely affect interpretations regarding progenitor cell potential and application for regenerative medicine. Here we report a direct comparison between human fetal and adult heart-derived cardiomyocyte progenitor cells (CMPCs). We show that fetal and adult CMPCs have distinct preferences to differentiate into mesodermal lineages. Under pro-angiogenic conditions, fetal CMPCs form more endothelial but less smooth muscle cells than adult CMPCs. Fetal CMPCs can also develop towards adipocytes, while neither fetal nor adult CMPCs show significant osteogenic differentiation. Interestingly, while both cell types differentiate into heart muscle cells, adult CMPCs give rise to ele! ctrophysiologically more mature cardiomyocytes than fetal CMPCs. Taken together, fetal CMPCs are suitable for molecular cell biology and developmental studies. The potential of adult CMPCs to form mature cardiomyocytes and smooth muscle cells may be essential for cardiac repair after transplantation into the injured heart. PMID: 20219011 [PubMed - as supplied by publisher] | | |
| Potential therapeutic applications of muscle-derived mesenchymal stem and progenitor cells.
March 12, 2010 at 6:16 AM
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| | Potential therapeutic applications of muscle-derived mesenchymal stem and progenitor cells. Expert Opin Biol Ther. 2010 Apr;10(4):505-17 Authors: Jackson WM, Nesti LJ, Tuan RS Importance of the field: Mesenchymal adult stem cells have properties that make them attractive for use in tissue engineering and regenerative medicine. They are inherently plastic, enabling them to differentiate along different lineages, and promote wound healing and regeneration of surrounding tissues by modulating immune and inflammatory responses, promoting angiogenesis and secreting other trophic factors. Unlike embryonic stem cells, clinical uses of mesenchymal stem cells are not encumbered by ethical considerations or legal restrictions. Areas covered in this review: We discuss skeletal muscle as a source of mesenchymal stem and progenitor cells by reviewing their biology and current applications in tissue engineering and regenerative medicine. This paper covers literature from the last 5 - 10 years. What the reader will gain: Skeletal muscle is a plentiful source of mesenchymal stem and progenitor cells. This tissue may be obtained via routine biopsy or co! llection after surgical debridement. We describe the biology of these cells and provide an overview of therapeutic applications currently being developed to take advantage of their regenerative properties. Take home message: There is potential for stem and progenitor cells derived from skeletal muscle to be incorporated in clinical interventions, either as a cellular therapy to modify the natural history of disease or as a component of engineered tissue constructs that can replace diseased or damaged tissues. PMID: 20218920 [PubMed - in process] | | |
| Quantification of fluorescence intensity of labeled human mesenchymal stem cells and cell counting of unlabelled cells in phase contrast imaging: An open source based algorithm.
March 12, 2010 at 6:16 AM
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| | Quantification of fluorescence intensity of labeled human mesenchymal stem cells and cell counting of unlabelled cells in phase contrast imaging: An open source based algorithm. Tissue Eng Part C Methods. 2010 Mar 10; Authors: Polzer H, Haasters F, Prall WC, Saller MM, Volkmer E, Drosse I, Mutschler W, Schieker M Assessment of cell fate is indispensable to evaluate cell-based therapies in regenerative medicine. Therefore, a widely used technique is fluorescence labelling. A major problem still is the standardized, non-invasive and reliable quantification of fluorescence intensity of adherent cell populations on single-cell level, since total fluorescence intensity must be correlated to the cell number. Consequently, the aim of the present study was to produce and validate an open source based algorithm, capable of measuring the total fluorescence intensity of cell populations and assessing the total cell number in phase contrast images. To verify the algorithms' capacity to assess fluorescence intensity, hMSCs were transduced to stably express eGFP and results produced by the algorithm were compared to flow cytometry analysis. No significant differences could be observed at any time (p>/=0.443). For validation of the algorithm for cell counting in phase contrast ima! ges, adherent hMSCs were manually counted and compared to results produced by the algorithm (correlation coefficient (CC) r=0.975), nuclei staining (CC r=0.997) and hemocytometer (CC r=0.629). We conclude that applying the developed algorithm in routine practice allows robust, fast and reproducible assessment of fluorescence intensity and cell numbers in simple large-scale microscopy. The method is easy to perform and open-source based. PMID: 20218817 [PubMed - as supplied by publisher] | | | | 
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