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| Selective culture of different types of human parotid gland cells.
July 21, 2010 at 10:46 AM
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| | Selective culture of different types of human parotid gland cells. Head Neck. 2010 Jul 19; Authors: Chan YH, Huang TW, Young TH, Lou PJ BACKGROUND.: Advances in salivary gland tissue engineering can benefit patients diagnosed with xerostomia. Complexity of the gland explains the urgent demand for a reliable protocol to isolate and expand various gland cells that can be used for further study. METHODS.: Three cells with different morphologies were isolated from the same human parotid glands using different culture medium systems and then were identified by the expressions from mRNA to the protein level. RESULTS.: Among the 34 specimens, parotid gland acinar cells, myoepithelial cells, and fibroblasts expressing specific markers that belonged to individual cell types, were successfully isolated and expanded from 30 specimens without a complex mechanical process and expensive flow technique. CONCLUSION.: The proposed protocol is simple with a high success rate to culture various gland cells, making it highly promising for use in future tissue engineering studies. (c) 2010 Wiley Periodicals, Inc. Head Neck, 2010. PMID: 20645288 [PubMed - as supplied by publisher] | | |
| Evaluation of early healing events around mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffold. An experimental study in Wistar rats.
July 21, 2010 at 10:46 AM
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| | Evaluation of early healing events around mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffold. An experimental study in Wistar rats. Oral Maxillofac Surg. 2010 Jul 20; Authors: Alhag M, Farrell E, Toner M, Claffey N, Lee TC, O'Brien F PURPOSE: Tissue engineering using cell-seeded biodegradable scaffolds offers a new bone regenerative approach that might circumvent many of the limitations of current therapeutic modalities. The aim of this experiment was to study the early healing events around mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffolds. METHODS: The 5-mm critical size defects were created in the calvarial bones of 41 Wistar rats. The defects were either left empty to serve as controls (n = 11), filled with cell-free scaffolds (n = 12), cell-seeded scaffolds that were maintained in standard culture medium (n = 9), or cell-seeded scaffolds that were maintained in osteoinductive factor-supplemented medium (n = 9). The animals were sacrificed at 7 days after surgery, and specimens were prepared for histological analysis. Early healing events such as host cell penetration, blood vessel in-growth, and scaffold integration were observed. The degree of inflammatory cell infiltrate was assessed. RESULTS: While defects in the control group healed with a thin fibrous tissue, the collagen-glycosaminoglycan scaffold in the test groups preserved the three-dimensional form of the defects. After 7 days in vivo, the scaffold maintained its integrity and appeared populated with host cells. The cell-seeded scaffold induced more inflammatory response compared to the cell-free scaffolds. New blood vessels and areas of early bone formation were also evident in the cell-seeded scaffolds. CONCLUSIONS: In conclusion, the findings show that mesenchymal stem cell-seeded collagen-glycosaminoglycan scaffolds have good tissue tolerance and exhibit an osteoinductive effect as indicated by early stage healing. PMID: 20644972 [PubMed - as supplied by publisher] | | |
| Bio-electrospraying and aerodynamically assisted bio-jetting whole human blood: Interrogating cell surface marker integrity.
July 21, 2010 at 10:46 AM
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| | Bio-electrospraying and aerodynamically assisted bio-jetting whole human blood: Interrogating cell surface marker integrity. Biomicrofluidics. 2010;4(1):11101 Authors: Joly P, Chavda N, Eddaoudi A, Jayasinghe SN Bio-electrospraying and aerodynamically assisted bio-jetting are two direct cell handling approaches recently pioneered, which have demonstrated significant applicability to the life sciences. These two bioprotocols have undergone scientific rigor, which have seen these techniques been explored in conjunction with a wide range of immortalized, primary and stem cells, and those whole organisms. Those studies have demonstrated a cellular population of >70% viable post-treatment in comparison with controls. Although, these studies assessed cellular viability, cell surface molecules play a critical role in several cellular functions, in particular, have importance to tissue engineering and regenerative medicine. Thus, in the studies reported herein, we demonstrate post-treated viable cells retain their cell surface marker expression levels in comparison to controls, over both short and long time points. Therefore, these studies further push back the frontiers of both bio-electrosprays and aerodynamically assisted bio-jetting in their endeavor as novel strategies for tissue engineering and regenerative biologymedicine with possible targeted clinical utility. PMID: 20644660 [PubMed - in process] | | |
| Cell type of origin influences the molecular and functional properties of mouse induced pluripotent stem cells.
July 21, 2010 at 10:46 AM
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| | Cell type of origin influences the molecular and functional properties of mouse induced pluripotent stem cells. Nat Biotechnol. 2010 Jul 19; Authors: Polo JM, Liu S, Figueroa ME, Kulalert W, Eminli S, Tan KY, Apostolou E, Stadtfeld M, Li Y, Shioda T, Natesan S, Wagers AJ, Melnick A, Evans T, Hochedlinger K Induced pluripotent stem cells (iPSCs) have been derived from various somatic cell populations through ectopic expression of defined factors. It remains unclear whether iPSCs generated from different cell types are molecularly and functionally similar. Here we show that iPSCs obtained from mouse fibroblasts, hematopoietic and myogenic cells exhibit distinct transcriptional and epigenetic patterns. Moreover, we demonstrate that cellular origin influences the in vitro differentiation potentials of iPSCs into embryoid bodies and different hematopoietic cell types. Notably, continuous passaging of iPSCs largely attenuates these differences. Our results suggest that early-passage iPSCs retain a transient epigenetic memory of their somatic cells of origin, which manifests as differential gene expression and altered differentiation capacity. These observations may influence ongoing attempts to use iPSCs for disease modeling and could also be exploited in potential therapeutic applications to enhance differentiation into desired cell lineages. PMID: 20644536 [PubMed - as supplied by publisher] | | |
| Isolating stem cells from soft musculoskeletal tissues.
July 21, 2010 at 10:46 AM
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| | Isolating stem cells from soft musculoskeletal tissues. J Vis Exp. 2010;(41): Authors: Li Y, Pan H, Huard J Adult stem cells have long been discussed in regards to their application in regenerative medicine. Adult stem cells have generated a great deal of excitement for treating injured and diseased tissues due to their impressive capabilities to undergo multi-lineage cell differentiation and their self-renewal ability. Most importantly, these qualities have made them advantageous for use in autologous cell transplantation therapies. The current protocol will introduce the readers to the modified preplate technique where soft tissues of the musculoskeletal system, e.g. tendon and muscle, are 1(st) enzymatically dissociated and then placed in collagen coated flasks with medium. The supernatant, which is composed of medium and the remaining floating cells, is serially transferred daily to new flasks. The stem cells are the slowest to adhere to the flasks which is usually takes 5-7 days (serial transfers or preplates) . By using this technique, adult stem cells present in these tissues can be easily harvested through fairly non-invasive procedures. PMID: 20644509 [PubMed - in process] | | |
| Isolation of Human Umbilical Arterial Smooth Muscle Cells (HUASMC).
July 21, 2010 at 10:46 AM
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| | Isolation of Human Umbilical Arterial Smooth Muscle Cells (HUASMC). J Vis Exp. 2010;(41) Authors: Ribeiro MP, Relvas R, Chiquita S, Correia ID The human umbilical cord (UC) is a biological sample that can be easily obtained just after birth. This biological sample is, most of the time, discarded and their collection does not imply any added risk to the newborn or mother s health. Moreover no ethical concerns are raised. The UC is composed by one vein and two arteries from which both endothelial cells (ECs) (1) and smooth muscle cells (SMCs) (2), two of the main cellular components of blood vessels, can be isolated. In this project the SMCs were obtained after enzymatic treatment of the UC arteries accordingly the experimental procedure previously described by Jaffe et al (3). After cell isolation they were kept in t-flash with DMEM-F12 supplemented with 5% of fetal bovine serum and were cultured for several passages. Cells maintained their morphological and other phenotypic characteristics in the different generations. The aim of this study was to isolate smooth muscle cells in order to use them as models for future assays with constrictor drugs, isolate and structurally characterize L-type calcium channels, to study cellular and molecular aspects of the vascular function (4) and to use them in tissue engineering. PMID: 20644508 [PubMed - as supplied by publisher] | | |
| Mapping the first stages of mesoderm commitment during differentiation of human embryonic stem cells.
July 21, 2010 at 10:46 AM
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| | Mapping the first stages of mesoderm commitment during differentiation of human embryonic stem cells. Proc Natl Acad Sci U S A. 2010 Jul 19; Authors: Evseenko D, Zhu Y, Schenke-Layland K, Kuo J, Latour B, Ge S, Scholes J, Dravid G, Li X, Maclellan WR, Crooks GM Our understanding of how mesodermal tissue is formed has been limited by the absence of specific and reliable markers of early mesoderm commitment. We report that mesoderm commitment from human embryonic stem cells (hESCs) is initiated by epithelial-to-mesenchymal transition (EMT) as shown by gene expression profiling and by reciprocal changes in expression of the cell surface proteins, EpCAM/CD326 and NCAM/CD56. Molecular and functional assays reveal that the earliest CD326(-)CD56(+) cells, generated from hESCs in the presence of activin A, BMP4, VEGF, and FGF2, represent a multipotent mesoderm-committed progenitor population. CD326(-)CD56(+) progenitors are unique in their ability to generate all mesodermal lineages including hematopoietic, endothelial, mesenchymal (bone, cartilage, fat, fibroblast), smooth muscle, and cardiomyocytes, while lacking the pluripotency of hESCs. CD326(-)CD56(+) cells are the precursors of previously reported, more lineage-restricted mesodermal progenitors. These findings present a unique approach to study how germ layer specification is regulated and offer a promising target for tissue engineering. PMID: 20643952 [PubMed - as supplied by publisher] | | |
| Aggregation of human mesenchymal stromal cells (MSCs) into 3D spheroids enhances their antiinflammatory properties.
July 21, 2010 at 10:46 AM
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| | Aggregation of human mesenchymal stromal cells (MSCs) into 3D spheroids enhances their antiinflammatory properties. Proc Natl Acad Sci U S A. 2010 Jul 19; Authors: Bartosh TJ, Ylöstalo JH, Mohammadipoor A, Bazhanov N, Coble K, Claypool K, Lee RH, Choi H, Prockop DJ Previous reports suggested that culture as 3D aggregates or as spheroids can increase the therapeutic potential of the adult stem/progenitor cells referred to as mesenchymal stem cells or multipotent mesenchymal stromal cells (MSCs). Here we used a hanging drop protocol to prepare human MSCs (hMSCs) as spheroids that maximally expressed TNFalpha stimulated gene/protein 6 (TSG-6), the antiinflammatory protein that was expressed at high levels by hMSCs trapped in the lung after i.v. infusion and that largely explained the beneficial effects of hMSCs in mice with myocardial infarcts. The properties of spheroid hMSCs were found to depend critically on the culture conditions. Under optimal conditions for expression of TSG-6, the hMSCs also expressed high levels of stanniocalcin-1, a protein with both antiinflammatory and antiapoptotic properties. In addition, they expressed high levels of three anticancer proteins: IL-24, TNFalpha-related apoptosis inducing ligand, and CD82. The spheroid hMSCs were more effective than hMSCs from adherent monolayer cultures in suppressing inflammatory responses in a coculture system with LPS-activated macrophages and in a mouse model for peritonitis. In addition, the spheroid hMSCs were about one-fourth the volume of hMSCs from adherent cultures. Apparently as a result, larger numbers of the cells trafficked through the lung after i.v. infusion and were recovered in spleen, liver, kidney, and heart. The data suggest that spheroid hMSCs may be more effective than hMSCs from adherent cultures in therapies for diseases characterized by sterile tissue injury and unresolved inflammation and for some cancers that are sensitive to antiinflammatory agents. PMID: 20643923 [PubMed - as supplied by publisher] | | |
| Synergic effects of crypt-like topography and ECM proteins on intestinal cell behavior in collagen based membranes.
July 21, 2010 at 10:46 AM
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| | Synergic effects of crypt-like topography and ECM proteins on intestinal cell behavior in collagen based membranes. Biomaterials. 2010 Jul 17; Authors: Wang L, Murthy SK, Barabino GA, Carrier RL The basement membrane of small intestinal epithelium possesses complex topography at multiple scales ranging from the mesoscale to nanoscale. Specifically, intestinal crypt-villus units are comprised of hundred-micron-scale well-like invaginations and finger-like projections; intestinal cell phenotype is related to location on this crypt-villus unit. A biomimetic intestinal cell culture system composed of type I collagen based permeable cell culture membranes incorporating both micron-scale intestinal crypt-like topography and nanometer scale topography was fabricated. Membranes were pre-incubated with either laminin (Ln) or fibronectin (Fn), inoculated with intestinal epithelial Caco-2 cells and cultured for 1-21 days to study the relative significance of influence of crypt-like topography and biomimetic substrate chemistry on cell phenotype. Crypt-like topography inhibited Caco-2 differentiation during early culture, as evidenced by slower cell spreading and lower brush border enzyme activity. For example, alanine aminopeptidase activity was lower on Ln-coated patterned collagen ( approximately 3.4+/-0.24mU/mg) compared to flat collagen (10.84+/-0.55mU/mg) at day 7. Caco-2 cultured on Fn-coated collagen started to spread earlier (1 day vs 3 days) and formed longer protrusions than on Ln-coated collagen. Pre-coating of Ln enhanced cell differentiation, as the maximum activity of a cell differentiation marker (alkaline phosphatase) was 2-3 times higher than on Fn-coated collagen, and maintained differentiated phenotype in long term (up to 21 days) culture. In general, compared to substrate topography, coating with ECM protein had more prominent and longer effect on cell behavior. Crypt-like topography affected Caco-2 spreading and differentiation during early culture, however the effect diminished as culture progressed. This information will benefit intestinal tissue engineering scaffold design, and modification of in vitro intestinal cell models. PMID: 20643478 [PubMed - as supplied by publisher] | | |
| Resident Cardiac Progenitor Cells: At the Heart of Regeneration.
July 21, 2010 at 10:46 AM
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| | Resident Cardiac Progenitor Cells: At the Heart of Regeneration. J Mol Cell Cardiol. 2010 Jul 16; Authors: Bollini S, Smart N, Riley PR Stem cell therapy has recently emerged as an innovative strategy over conventional cardiovascular treatments to restore cardiac function in patients affected by ischemic heart disease. Various stem cell populations have been tested and their potential for cardiac repair analyzed. Embryonic stem cells retain the greatest differentiation potential, but concerns persist with regard to their immunogenic and teratogenic effects. Although adult somatic stem cells are not tumourigenic and easier to use in an autologous setting, they exist in small numbers and possess reduced differentiation potential. Traditionally the heart was considered to be a post-mitotic organ; however, this dogma has recently been challenged with the identification of a reservoir of resident stem cells, defined as cardiac progenitor cells (CPCs). These endogenous progenitors may represent the best candidates for cardiovascular cell therapy, as they are tissue-specific, often pre-committed to a cardiac fate, and display a greater propensity to differentiate towards cardiovascular lineages. This review will focus on current research into the biology of CPCs and their regenerative potential. PMID: 20643135 [PubMed - as supplied by publisher] | | |
| Release kinetics of VEGF165 from a collagen matrix and structural matrix changes in a circulation model.
July 21, 2010 at 10:46 AM
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| | Release kinetics of VEGF165 from a collagen matrix and structural matrix changes in a circulation model. Head Face Med. 2010 Jul 19;6(1):17 Authors: Kleinheinz J, Jung S, Wermker K, Fischer C, Joos U ABSTRACT: BACKGROUND: Current approaches in bone regeneration combine osteoconductive scaffolds with bioactive cytokines like BMP or VEGF. The idea of our in-vitro trial was to apply VEGF165 in gradient concentrations to an equine collagen carrier and to study pharmacological and morphological characteristics of the complex in a circulation model. METHODS: Release kinetics of VEGF165 complexed in different quantities in a collagen matrix were determined in a circulation model by quantifying protein concentration with ELISA over a period of 5 days. The structural changes of the collagen matrix were assessed with light microscopy, native scanning electron microscopy (SEM) as well as with immuno-gold-labelling technique in scanning and transmission electron microscopy (TEM). RESULTS: We established a biological half-life for VEGF165 of 90 minutes. In a half-logarithmic presentation the VEGF165 release showed a linear declining gradient; the release kinetics were not depending on VEGF165 concentrations. After 12 hours VEGF release reached a plateau, after 48 hours VEGF165 was no longer detectable in the complexes charged with lower doses, but still measurable in the 80 ug sample. At the beginning of the study a smear layer was visible on the surface of the complex. After the wash out of the protein in the first days the natural structure of the collagen appeared and did not change over the test period. CONCLUSIONS: By defining the pharmacological and morphological profile of a cytokine collagen complex in a circulation model our data paves the way for further in-vivo studies where additional biological side effects will have to be considered. VEGF165 linked to collagen fibrils shows its improved stability in direct electron microscopic imaging as well as in prolonged release from the matrix. Our in-vitro trial substantiates the position of cytokine collagen complexes as innovative and effective treatment tools in regenerative medicine and and may initiate further clinical research. PMID: 20642842 [PubMed - as supplied by publisher] | | |
| Reconstruction of the auricle. Preface.
July 21, 2010 at 10:46 AM
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| | Reconstruction of the auricle. Preface. Adv Otorhinolaryngol. 2010;68:VI-VIII Authors: Staudenmaier R PMID: 20586133 [PubMed - indexed for MEDLINE] | | |
| Preparation, fabrication and biocompatibility of novel injectable temperature-sensitive chitosan/glycerophosphate/collagen hydrogels.
July 21, 2010 at 4:47 AM
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| | Preparation, fabrication and biocompatibility of novel injectable temperature-sensitive chitosan/glycerophosphate/collagen hydrogels. J Mater Sci Mater Med. 2010 Jul 18; Authors: Song K, Qiao M, Liu T, Jiang B, Macedo HM, Ma X, Cui Z This paper introduces a novel type of injectable temperature-sensitive chitosan/glycerophosphate/collagen (C/GP/Co) hydrogel that possesses great biocompatibility for the culture of adipose tissue-derived stem cells. The C/GP/Co hydrogel is prepared by mixing 2.2% (v/v) chitosan with 50% (w/w) beta-glycerophosphate at different proportions and afterwards adding 2 mg/ml of collagen. The gelation time of the prepared solution at 37 degrees C was found to be of around 12 min. The inner structure of the hydrogel presented a porous spongy structure, as observed by scanning electron microscopy. Moreover, the osmolality of the medium in contact with the hydrogel was in the range of 310-330 mmol kg(-1). These analyses have shown that the C/GP/Co hydrogels are structurally feasible for cell culture, while their biocompatibility was further examined. Human adipose tissue-derived stem cells (ADSCs) were seeded into the developed C/GP and C/GP/Co hydrogels (The ratios of C/GP and C/GP/Co were 5:1 and 5:1:6, respectively), and the cellular growth was periodically observed under an inverted microscope. The proliferation of ADSCs was detected using cck-8 kits, while cell apoptosis was determined by a Live/Dead Viability/Cytotoxicity kit. After 7 days of culture, cells within the C/GP/Co hydrogels displayed a typical adherent cell morphology and good proliferation with very high cellular viability. It was thus demonstrated that the novel C/GP/Co hydrogel herein described possess excellent cellular compatibility, representing a new alternative as a scaffold for tissue engineering, with the added advantage of being a gel at the body's temperature that turns liquid at room temperature. PMID: 20640914 [PubMed - as supplied by publisher] | | |
| Electrospun poly(D: /L: -lactide-co-L: -lactide) hybrid matrix: a novel scaffold material for soft tissue engineering.
July 21, 2010 at 4:47 AM
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| | Electrospun poly(D: /L: -lactide-co-L: -lactide) hybrid matrix: a novel scaffold material for soft tissue engineering. J Mater Sci Mater Med. 2010 Jul 17; Authors: Kluger PJ, Wyrwa R, Weisser J, Maierle J, Votteler M, Rode C, Schnabelrauch M, Walles H, Schenke-Layland K Electrospinning is a long-known polymer processing technique that has received more interest and attention in recent years due to its versatility and potential use in the field of biomedical research. The fabrication of three-dimensional (3D) electrospun matrices for drug delivery and tissue engineering is of particular interest. In the present study, we identified optimal conditions to generate novel electrospun polymeric scaffolds composed of poly-D: /L: -lactide and poly-L: -lactide in the ratio 50:50. Scanning electron microscopic analyses revealed that the generated poly(D: /L: -lactide-co-L: -lactide) electrospun hybrid microfibers possessed a unique porous high surface area mimicking native extracellular matrix (ECM). To assess cytocompatibility, we isolated dermal fibroblasts from human skin biopsies. After 5 days of in vitro culture, the fibroblasts adhered, migrated and proliferated on the newly created 3D scaffolds. Our data demonstrate the applicability of electrospun poly(D: /L: -lactide-co-L: -lactide) scaffolds to serve as substrates for regenerative medicine applications with special focus on skin tissue engineering. PMID: 20640490 [PubMed - as supplied by publisher] | | |
| Local anesthetics have a major impact on viability of preadipocytes and their differentiation to adipocytes.
July 21, 2010 at 4:47 AM
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| | Local anesthetics have a major impact on viability of preadipocytes and their differentiation to adipocytes. Plast Reconstr Surg. 2010 Jul 15; Authors: Keck M, Zeyda M, Gollinger K, Buriak S, Kamolz LP, Frey M, Stulnig TM BACKGROUND:: Autologous fat transplantation is a well established technique in surgery. Moreover, the use of preadipocytes in soft tissue engineering is currently intensely investigated. Current efforts focus on identifying maneuvers that may minimize resorption and provide predictable late results. Aim of this study was to investigate the influence of different local anesthetics frequently used in clinical practice on the viability of preadipocytes and their ability to differentiate into adipocytes. METHODS:: Human preadipocytes were isolated from subcutaneous adipose tissue of 15 patients and treated with bupivacaine, mepivacaine, ropivacaine, articaine/epinephrine, and lidocaine for 30 minutes. Viability was determined directly after treatment and during the following cultivation. Differentiation of preadipocytes was determined by expression of the adipocyte marker adiponectin. RESULTS:: While the immediate effects of mepivacaine and ropivacaine were only moderate, treatment with articaine/epinephrine and lidocaine strongly impaired preadipocyte viability. Cells normally attached to the culture dishes and proliferated irrespective of the previous treatment. During long-term cultivation, articaine/epinephrine-treated cell viability markedly decreased, while other local anesthetics had no impact. Despite normal phenotypical appearance of cells treated with bupivacaine, mepivacaine, ropivacaine, and lidocaine, all local anesthetics markedly impaired adipocyte differentiation as determined by adiponectin expression. CONCLUSION:: Our results show that there is a marked influence of local anesthetics not only on the quantity of viable preadipocytes but also on their quality as determined by their ability to differentiate into mature adipocytes. Therefore these results should be considered in the context of autologous fat transfer as well as soft tissue engineering. PMID: 20639800 [PubMed - as supplied by publisher] | | |
| Spinal Effects of the Fesoterodine Metabolite 5-Hydroxymethyl Tolterodine and/or Doxazosin in Rats With or Without Partial Urethral Obstruction.
July 21, 2010 at 4:47 AM
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| | Spinal Effects of the Fesoterodine Metabolite 5-Hydroxymethyl Tolterodine and/or Doxazosin in Rats With or Without Partial Urethral Obstruction. J Urol. 2010 Aug;184(2):783-789 Authors: Füllhase C, Soler R, Gratzke C, Brodsky M, Christ GJ, Andersson KE PURPOSE: The combination of muscarinic receptor and alpha(1)-adrenoceptor antagonists is increasingly used for benign prostatic hyperplasia related lower urinary tract symptoms. In addition to the well established peripheral site of action, little is known about the central effects of muscarinic receptor antagonists and muscarinic receptor/alpha(1)-adrenoceptor antagonist combinations on bladder function, partly due to poor brain penetration after systemic administration. We assessed the effects of intrathecal 5-hydroxymethyl tolterodine, an active metabolite of fesoterodine, in obstructed and nonobstructed rats, and of combined intrathecal 5-hydroxymethyl tolterodine/doxazosin in a rat model of partial urethral obstruction. MATERIALS AND METHODS: We used 80 male Sprague-Dawley(R) rats to test various doses of intrathecal 5-hydroxymethyl tolterodine and/or intrathecal doxazosin on urodynamic parameters. Urodynamic evaluation without anesthesia was done 3 days after bladder and intrathecal catheterization. Two weeks before urodynamics 40 rats underwent partial urethral obstruction. RESULTS: Intrathecal 5-hydroxymethyl tolterodine had no urodynamic effects in nonobstructed rats. Compared to controls obstructed rats had increased bladder pressure and weight, and voiding frequency. In obstructed rats 5-hydroxymethyl tolterodine restored urodynamic parameters to those seen in nonobstructed animals. Doxazosin had effects similar to those of intrathecal 5-hydroxymethyl tolterodine. When the 2 drugs were combined, at the doses used only small additional effects were observed. CONCLUSIONS: Urodynamic changes in obstructed rats can be normalized by intrathecal 5-hydroxymethyl tolterodine and by intrathecal doxazosin. The central pathways on which the 2 drugs act seem to be up-regulated with partial urethral obstruction and less relevant under normal conditions. PMID: 20639056 [PubMed - as supplied by publisher] | | |
| The regulation of phenotype of cultured tenocytes by microgrooved surface structure.
July 21, 2010 at 4:47 AM
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| | The regulation of phenotype of cultured tenocytes by microgrooved surface structure. Biomaterials. 2010 Sep;31(27):6952-6958 Authors: Zhu J, Li J, Wang B, Zhang WJ, Zhou G, Cao Y, Liu W To maintain or enhance cell function by controlling its shape is an important consideration in scaffold design. Tenocyte is characterized by its unique elongated cell shape and the role remains unexplored. In this study, primary porcine tenocytes of newborn pigs were cultured respectively on culture dish (Group A), smooth (Group B) or microgroove silicone membrane (Group C, enforcing an elongated morphology) to observe the effect of cell shape on tenocyte phenotype. The results showed that elongated morphology (Group C) could help in vitro passaged tenocytes to retain their phenotype and function by maintaining the expression of tenomodulin (tenocyte marker) and collagen I (functional molecule). By contrast, the spread tenocytes (Groups A and B) lost or significantly reduced the expression of tenomodulin or collagen I respectively. Interestingly, the lost tenomodulin expression of Group B cells could be regained after being switched to microgroove culture condition of Group C. In addition, significantly increased RhoA-ATP level and reduced ROCK activity were found associated with elongated morphology and artificially activating RhoA or inhibiting ROCK could lead to increased tenomodulin expression in spread cells. Collectively, these results confirm that elongated morphology is essential for tenocytes to keep their phenotype and function and can redifferentiate the dedifferentiated tenocytes by the participation of RhoA/ROCK signaling, and these findings may provide insight into the design of advanced scaffold for tendon engineering. PMID: 20638974 [PubMed - as supplied by publisher] | | |
| The effect of a slow mode of BMP-2 delivery on the inflammatory response provoked by bone-defect-filling polymeric scaffolds.
July 21, 2010 at 4:47 AM
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| | The effect of a slow mode of BMP-2 delivery on the inflammatory response provoked by bone-defect-filling polymeric scaffolds. Biomaterials. 2010 Jul 17; Authors: Wu G, Liu Y, Iizuka T, Hunziker EB We investigated the inflammatory response to, and the osteoinductive efficacies of, four polymers (collagen, Ethisorb, PLGA and Polyactive((R))) that bore either an adsorbed (fast-release kinetics) or a calcium-phosphate-coating-incorporated (slow-release kinetics) depot of BMP-2. Titanium-plate-supported discs of each polymer (n = 6 per group) were implanted at an ectopic (subcutaneous) ossification site in rats (n = 48). Five weeks later, they were retrieved for a histomorphometric analysis of the volumes of ectopic bone and foreign-body giant cells (a gauge of inflammatory reactivity), and the degree of polymer degradation. For each polymer, the osteoinductive efficacy of BMP-2 was higher when it was incorporated into a coating than when it was directly adsorbed onto the material. This mode of BMP-2 carriage was consistently associated with an attenuation of the inflammatory response. For coated materials, the volume density of foreign-body giant cells was inversely correlated with the volume density of bone (r(2) = 0.96), and the volume density of bone was directly proportional to the surface-area density of the polymer (r(2) = 0.97). Following coating degradation, other competitive factors, such as the biocompatibility and the biodegradability of the polymer itself, came into play. PMID: 20638718 [PubMed - as supplied by publisher] | | |
| Functional skeletal muscle formation with a biologic scaffold.
July 21, 2010 at 4:47 AM
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| | Functional skeletal muscle formation with a biologic scaffold. Biomaterials. 2010 Jul 16; Authors: Valentin JE, Turner NJ, Gilbert TW, Badylak SF Biologic scaffolds composed of extracellular matrix (ECM) have been used to reinforce or replace damaged or missing musculotendinous tissues in both preclinical studies and in human clinical applications. However, most studies have focused upon morphologic endpoints and few studies have assessed the in-situ functionality of newly formed tissue; especially new skeletal muscle tissue. The objective of the present study was to determine both the in-situ tetanic contractile response and histomorphologic characteristics of skeletal muscle tissue reconstructed using one of four test articles in a rodent abdominal wall model: 1) porcine small intestinal submucosa (SIS)-ECM; 2) carbodiimide-crosslinked porcine SIS-ECM; 3) autologous tissue; or 4) polypropylene mesh. Six months after surgery, the remodeled SIS-ECM showed almost complete replacement by islands and sheets of skeletal muscle, which generated a similar maximal contractile force to native tissue but with greater resistance to fatigue. The autologous tissue graft was replaced by a mixture of collagenous connective tissue, adipose tissue with fewer islands of skeletal muscle compared to SIS-ECM and a similar fatigue resistance to native muscle. Carbodiimide-crosslinked SIS-ECM and polypropylene mesh were characterized by a chronic inflammatory response and produced little or no measurable tetanic force. The findings of this study show that non-crosslinked xenogeneic SIS scaffolds and autologous tissue are associated with the restoration of functional skeletal muscle with histomorphologic characteristics that resemble native muscle. PMID: 20638716 [PubMed - as supplied by publisher] | | |
| Availability of Adipose-Derived Stem Cells in Patients Undergoing Vascular Surgical Procedures.
July 21, 2010 at 4:47 AM
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| | Availability of Adipose-Derived Stem Cells in Patients Undergoing Vascular Surgical Procedures. J Surg Res. 2010 May 10; Authors: Harris LJ, Zhang P, Abdollahi H, Tarola NA, Dimatteo C, McIlhenny SE, Tulenko TN, Dimuzio PJ BACKGROUND: Most research evaluating adipose-derived stem cells (ASC) uses tissue obtained from young, healthy patients undergoing plastic surgical procedures. Given the propensity of other adult stem cell lines to diminish with increasing patient age and co-morbidities, we assess the availability of ASC in elderly patients undergoing vascular surgical procedures, and evaluate their acquisition of endothelial cell (EC) traits to define their potential use in vascular tissue engineering. METHODS AND METHODS: Adipose tissue obtained by liposuction from patients undergoing vascular procedures (n = 50) was digested with collagenase and centrifuged to remove mature adipocytes. The resultant number of cells, defined as the stromal-vascular (SV) pellet, was quantified. Following a 7-d culture period and negative selection for CD31 and CD45, the resultant number of ASC was quantified. After culture in differentiating media (EMG-2), ASCs were tested for the acquisition of endothelial-specific traits (expression of CD31, realignment in shear, cord formation on Matrigel). RESULTS: The SV pellet contained 2.87 +/- 0.34 x 10(5) cells/g fat, and the resultant number of ASCs obtained was 1.41 +/- 0.18 x 10(5) cells/g fat. Flow cytometry revealed a homogeneous ASC population (>98% positive for CD13, 29, 90). Advanced age or co-morbidity (obesity, diabetes, renal or peripheral vascular disease) did not significantly alter yield of ASC. After culture in differentiating media (EMG-2), ASCs acquired each of the endothelial-specific traits. CONCLUSION: ASC isolation appears independent of age and co-morbidities, and ASCs harvested from patients with vascular disease retain their ability to differentiate into endothelial-like cells. Adipose tissue, therefore, is a practical source of autologous, adult stem cells for vascular tissue engineering. PMID: 20638677 [PubMed - as supplied by publisher] | | |
| Derivation efficiency, cell proliferation, freeze-thaw survival, stem-cell properties and differentiation of human Wharton's jelly stem cells.
July 21, 2010 at 4:47 AM
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| | Derivation efficiency, cell proliferation, freeze-thaw survival, stem-cell properties and differentiation of human Wharton's jelly stem cells. Reprod Biomed Online. 2010 Apr 24; Authors: Fong CY, Subramanian A, Biswas A, Gauthaman K, Srikanth P, Hande MP, Bongso A Human mesenchymal stem cells (MSC) are non-controversial multipotent stem cells. Their presence in umbilical cord blood (UCB) has been debated in some studies and others report low counts per cord blood unit and poor proliferation rates. On the other hand, Wharton's jelly of human umbilical cords appears to be a rich source of human MSC. This study derived 13 human Wharton's jelly stem cell (WJSC) lines from 13 human umbilical cords (100%) and recovered 4.7 +/- 0.2x10(6) live WJSC/cm of cord before culture. Complex culture medium produced greater proliferation rates of the WJSC in culture compared with simple medium. The mean population doubling times were 24.47 +/- 0.33 to 26.25 +/- 0.50h in complex medium. The stem-cell markers of the WJSC were retained for at least 10 passages in both media. After programmed machine freezing, the thaw-survival rates of WJSC were 85-90% and they could be differentiated into neurons. Given the high derivation efficiency, availability of large numbers of fresh live cells, high expansion capabilities, prolonged maintenance of stem-cell properties and differentiation potential, it is proposed that human WJSC may be frozen at the same time as UCB in cord blood banks for regenerative medicine purposes. PMID: 20638335 [PubMed - as supplied by publisher] | | |
| Engineering more than a cell: vascularization strategies in tissue engineering.
July 21, 2010 at 4:47 AM
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| | Engineering more than a cell: vascularization strategies in tissue engineering. Curr Opin Biotechnol. 2010 Jul 15; Authors: Phelps EA, GarcÃa AJ Host integration and performance of engineered tissues have been severely limited by the lack of robust strategies to generate patent vascularization and tissue perfusion. This review highlights a selection of exciting developments in vascularization approaches for tissue engineering research. Current strategies for vascularization in tissue engineering are related to growth factor signaling and delivery, cell transplantation, bioactive smart matrix materials, and directed fabrication. Application of these techniques to in vivo models has resulted in a number of robust host vascular responses, especially with synergistic and engineered bioactive systems. The future outlook of the field includes refinement and development of new technologies for vascularization and combining these techniques with functional repair models for metabolically active tissues and relevant disease states. PMID: 20638268 [PubMed - as supplied by publisher] | | |
| The non-covalent decoration of self-assembling protein fibers.
July 21, 2010 at 4:47 AM
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| | The non-covalent decoration of self-assembling protein fibers. Biomaterials. 2010 Jul 15; Authors: Mahmoud ZN, Grundy DJ, Channon KJ, Woolfson DN The design of self-assembling fibers presents challenges in basic science, and has potential for developing materials for applications in areas such as tissue engineering. A contemporary issue in the field is the construction of multi-component, functionalized systems. Previously, we have developed peptide-based fibers, the SAF system, that comprises two complementary peptides, which affords considerable control over assembly and morphology. Here we present a straightforward route to functionalizing the SAFs with small molecules and, subsequently, other moieties. This is achieved via non-covalent recruitment of charged peptide tags, which offers advantages such as further control, reversibility, and future prospects for developing recombinant tags. We demonstrate the concept by appending fluorescent labels and biotin (and thence gold nanoparticles) to the peptides, and visualising the resulting decorated SAFs by light and electron microscopy. The peptide tags bind in the nm-mum range, and show specificity compared with control peptides, and for the SAFs over similar alpha-helix-based peptide fibers. PMID: 20638122 [PubMed - as supplied by publisher] | | |
| Fibrin glue as a drug delivery system.
July 21, 2010 at 4:47 AM
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| | Fibrin glue as a drug delivery system. J Control Release. 2010 Jul 14; Authors: Spicer PP, Mikos AG Fibrin glue has been used surgically for decades for hemostasis as well as a sealant. It has also been researched as both a gel for cell delivery and a vehicle for drug delivery. The drug delivery applications for fibrin glue span tissue engineering to chemotherapy and involve several mechanisms for drug matrix interactions and control of release kinetics. Additionally, drugs or factors can be loaded in the gel via impregnation and tethering to the gel through covalent linkages or affinity based systems. This review highlights recent research of fibrin glue as a drug delivery vehicle. PMID: 20637815 [PubMed - as supplied by publisher] | | |
| Characterization of collagen/hydroxyapatite composite sponges as a potential bone substitute.
July 21, 2010 at 4:47 AM
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| | Characterization of collagen/hydroxyapatite composite sponges as a potential bone substitute. Int J Biol Macromol. 2010 Jul 14; Authors: Sionkowska A, Kozłowska J Hydroxyapatite and collagen composites (HAp/Col) have the potential in mimicking and replacing skeletal bones. Their combination should prove beneficial for bone tissue engineering due to their natural biological resemblance and properties. In this study, hydroxyapatite and collagen isolated from animal tendons were used in different proportions as composites. Sponges were prepared by freezing and lyophylization of corresponding composite solutions. The properties of composite sponges, such as microstructure, chemical and physical properties were studied. In the present investigation, a collagen sponge and a composite sponge made of composite of HAp/Col were prepared in our lab and characterized by attenuated total reflection Fourier transform infra-red spectroscopy, thermogravimetric analysis and scanning electron microscopy (SEM). Infrared spectroscopy (IR) in combination with attenuated total reflection (ATR) spectroscopy is one of the most widely used technique for surface infrared analysis. The ATR-IR analysis did not indicate shift of the band corresponding to-COO(-) for none of the used HAp/Col ratios. Thermogravimetric results suggested that collagen chains had been embedded with HAp to several complexes with different thermal stability. SEM was used to observe the morphology and pore size of the sponges. SEM observations showed the sponges of HAp/Col with fully interconective macroporosity. PMID: 20637799 [PubMed - as supplied by publisher] | | |
| Transplantation of marrow-derived cardiac stem cells carried in designer self-assembling peptide nanofibers improves cardiac function after myocardial infarction.
July 21, 2010 at 4:47 AM
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| | Transplantation of marrow-derived cardiac stem cells carried in designer self-assembling peptide nanofibers improves cardiac function after myocardial infarction. Biochem Biophys Res Commun. 2010 Jul 14; Authors: Guo HD, Cui GH, Wang HJ, Tan YZ Progress in stem cell transplantation for the treatment of myocardial infarction is hampered by the poor retention and survival of the implanted cells. To enhance cell survival and differentiation and thereby improve the efficiency of stem cell therapy, we constructed a novel self-assembling peptide by attaching an RGDSP cell-adhesion motif to the self-assembling peptide RADA16. c-kit(pos)/Nkx2.5(low)/GATA4(low) marrow-derived cardiac stem cells (MCSCs), which have a specific potential to differentiate into cardiomyocytes, were isolated from rat bone marrow. The cytoprotective effects of RGDSP scaffolds were assessed by exposure of MCSCs to anoxia in vitro. The efficacy of transplanting MCSCs in RGDSP scaffolds was evaluated in a female rat MI model. The designer self-assembling peptide self-assembled into RGDSP nanofiber scaffolds under physiological conditions. RGDSP scaffolds were beneficial for the growth of MCSCs and protected them from apoptosis and necrosis caused by anoxia. In a rat MI model, cardiac function was improved and collagen deposition was markedly reduced in the group receiving MCSCs in RGDSP scaffolds compared with groups receiving MCSCs alone, RGDSP scaffolds alone or MCSCs in RADA16 scaffolds. There were more surviving MCSCs in the group receiving MCSCs in RGDSP scaffolds than in the groups receiving MCSCs alone or MCSCs in RADA16 scaffolds. Most of the Y chromosome-positive cells expressed cardiac troponin T and connexin43 (Cx-43). These results suggest that RGDSP scaffolds provide a suitable microenvironment for the survival and differentiation of MCSCs. RGDSP scaffolds enhanced the efficacy of MCSC transplantation to repair myocardium and improve cardiac function. PMID: 20637726 [PubMed - as supplied by publisher] | | |
| Immediate and gradual gene expression changes in telomerase over-expressing fibroblasts.
July 21, 2010 at 4:47 AM
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| | Immediate and gradual gene expression changes in telomerase over-expressing fibroblasts. Biochem Biophys Res Commun. 2010 Jul 14; Authors: Daniels DJ, Clothier C, Swan DC, Saretzki G Most human somatic cells contain no or very low levels of telomerase. The over-expression of the catalytic subunit (hTERT) of human telomerase is a common method to generate cells with a greatly prolonged lifespan. These cells serve as models for cells that are either difficult to cultivate or have a limited lifespan in vitro. In addition, hTERT over-expressing cells are thought to be a useful resource for tissue engineering and regenerative medicine. While tumour suppressors and cell cycle checkpoints are maintained for an extended period in most hTERT over-expressing cells we found that there is a gradual change in gene expression over a range of 130 population doublings (PD) for the majority of genes analysed. Seven genes were significantly down-regulated with increasing population doublings (PDs), while only two were up-regulated. One gene, stanniocalcin 2, was highly expressed in parental fibroblasts but completely diminished as a consequence of hTERT transgene expression. These data demonstrate that in hTERT over-expressing cells 2 different types of expression changes occur: one can be directly associated with hTERT transgene expression itself, while others might occur more gradual and with varying kinetics. These changes should be taken into account when these cells are used as functional models or for regenerative purposes. PMID: 20637725 [PubMed - as supplied by publisher] | | |
| Environmental regulation of valvulogenesis: implications for tissue engineering.
July 21, 2010 at 4:47 AM
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| | Environmental regulation of valvulogenesis: implications for tissue engineering. Eur J Cardiothorac Surg. 2010 Jul 14; Authors: Riem Vis PW, Kluin J, Sluijter JP, van Herwerden LA, Bouten CV Ongoing research efforts aim at improving the creation of tissue-engineered heart valves for in vivo systemic application. Hence, in vitro studies concentrate on optimising culture protocols incorporating biological as well as biophysical stimuli for tissue development. Important lessons can be drawn from valvulogenesis to mimic natural valve development in vitro. Here, we review the up-to-date status of valvulogenesis, focussing on the biomolecular and biophysical regulation of semilunar valve development. In addition, we discuss potential benefits of incorporating concepts derived from valvulogenesis, as well as alternative approaches, in tissue-engineering protocols, to improve in vitro valve development. The combined efforts from clinicians, cell biologists and engineers are required to implement and evaluate these approaches to achieve optimised protocols for heart-valve tissue engineering. PMID: 20637649 [PubMed - as supplied by publisher] | | |
| Cells preferentially grow on rough substrates.
July 21, 2010 at 4:47 AM
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| | Cells preferentially grow on rough substrates. Biomaterials. 2010 Jul 14; Authors: Gentile F, Tirinato L, Battista E, Causa F, Liberale C, di Fabrizio EM, Decuzzi P Substrate nanotopography affects cell adhesion and proliferation and is fundamental to the rational design of bio-adhesives, to tissue engineering and to the development of assays for in-vitro screening. Cell behavior on rough substrates is still elusive, and the results presented in the open literature remain controversial. Here, the proliferation of cells on electrochemically etched silicon substrates with different roughness and nearly similar surface energy was studied over three days with confocal and atomic force microscopy. The surface profile of the substrates is a self-affine fractal with a roughness R(a) growing with the etching time from approximately 2 to 100 nm and a fractal dimension D ranging between about 2 (nominally flat surface) and 2.6. For four cell types, the number of adhering cells and their proliferation rates exhibited a maximum on moderately rough (R(a) approximately 10-45 nm) nearly Brownian (D approximately 2.5) substrates. The observed cell behavior was satisfactorily interpreted within the theory of adhesion to randomly rough solids. These findings demonstrated the importance of nanogeometry in cell stable adhesion and growth, suggesting that moderately rough substrates with large fractal dimension could selectively boost cell proliferation. PMID: 20637503 [PubMed - as supplied by publisher] | | |
| Isolation of short peptide fragments from alpha-synuclein fibril core identifies a residue important for fibril nucleation: A possible implication for diagnostic applications.
July 21, 2010 at 4:47 AM
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| | Isolation of short peptide fragments from alpha-synuclein fibril core identifies a residue important for fibril nucleation: A possible implication for diagnostic applications. Biochim Biophys Acta. 2010 Jul 13; Authors: Yagi H, Takeuchi H, Ogawa S, Ito N, Sakane I, Hongo K, Mizobata T, Goto Y, Kawata Y alpha-Synuclein is one of the causative proteins of the neurodegenerative disorder, Parkinson's disease. Deposits of alpha-synuclein called Lewy bodies are a hallmark of this disorder, and is implicated in its progression. In order to understand the mechanism of amyloid fibril formation of alpha-synuclein in more detail, in this study we have isolated a specific, ~20 residue peptide region of the alpha-synuclein fibril core, using a combination of Edman degradation and mass-spectroscopy analyses of protease-resistant samples. Starting from this core peptide sequence, we then synthesized a series of peptides that undergo aggregation and fibril formation under similar conditions. Interestingly, in a derivative peptide where a crucial phenylalanine residue was changed to a glycine, the ability to initiate spontaneous fibril formation was abolished, while the ability to extend from preexisting fibril seeds was conserved. This fibril extension occurred irrespective of the source of the initial fibril seed, as demonstrated in experiments using fibril seeds of insulin, lysozyme, and GroES. This interesting ability suggests that this peptide might form the basis for a possible diagnostic tool useful in detecting the presence of various fibrillogenic factors. PMID: 20637318 [PubMed - as supplied by publisher] | | |
| Activin A expression regulates multipotency of mesenchymal progenitor cells.
July 21, 2010 at 4:47 AM
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| | Activin A expression regulates multipotency of mesenchymal progenitor cells. Stem Cell Res Ther. 2010;1(2):11 Authors: Djouad F, Jackson WM, Bobick BE, Janjanin S, Song Y, Huang GT, Tuan RS ABSTRACT : INTRODUCTION : Bone marrow (BM) stroma currently represents the most common and investigated source of mesenchymal progenitor cells (MPCs); however, comparable adult progenitor or stem cells have also been isolated from a wide variety of tissues. This study aims to assess the functional similarities of MPCs from different tissues and to identify specific factor(s) related to their multipotency. METHODS : For this purpose, we directly compared MPCs isolated from different adult tissues, including bone marrow, tonsil, muscle, and dental pulp. We first examined and compared proliferation rates, immunomodulatory properties, and multidifferentiation potential of these MPCs in vitro. Next, we specifically evaluated activin A expression profile and activin A:follistatin ratio in MPCs from the four sources. RESULTS : The multidifferentiation potential of the MPCs is correlated with activin A level and/or the activin A:follistatin ratio. Interestingly, by siRNA-mediated activin A knockdown, activin A was shown to be required for the chondrogenic and osteogenic differentiation of MPCs. These findings strongly suggest that activin A has a pivotal differentiation-related role in the early stages of chondrogenesis and osteogenesis while inhibiting adipogenesis of MPCs. CONCLUSIONS : This comparative analysis of MPCs from different tissue sources also identifies bone marrow-derived MPCs as the most potent MPCs in terms of multilineage differentiation and immunosuppression, two key requirements in cell-based regenerative medicine. In addition, this study implicates the significance of activin A as a functional marker of MPC identity. PMID: 20637060 [PubMed - as supplied by publisher] | | |
| Bone tissue engineering with human stem cells.
July 21, 2010 at 4:47 AM
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| | Bone tissue engineering with human stem cells. Stem Cell Res Ther. 2010;1(2):10 Authors: Marot D, Knezevic M, Novakovic GV ABSTRACT : Treatment of extensive bone defects requires autologous bone grafting or implantation of bone substitute materials. An attractive alternative has been to engineer fully viable, biological bone grafts in vitro by culturing osteogenic cells within three-dimensional scaffolds, under conditions supporting bone formation. Such grafts could be used for implantation, but also as physiologically relevant models in basic and translational studies of bone development, disease and drug discovery. A source of human cells that can be derived in large numbers from a small initial harvest and predictably differentiated into bone forming cells is critically important for engineering human bone grafts. We discuss the characteristics and limitations of various types of human embryonic and adult stem cells, and their utility for bone tissue engineering. PMID: 20637059 [PubMed - as supplied by publisher] | | |
| Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model.
July 21, 2010 at 4:47 AM
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| | Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model. J Cell Mol Med. 2010 Jul 15; Authors: Boos AM, Loew JS, Deschler G, Arkudas A, Bleiziffer O, Gulle H, Dragu A, Kneser U, Horch RE, Beier JP Abstract Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell - transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without BMP-2 to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using FACS and rtPCR analysis before subcutaneous implantation in combination with BMP-2 and beta-TCP/HA granules. Constructs were explanted after 1 to 12 weeks followed by histological and rtPCR evaluation. Sheep MSC were CD29, CD44 and CD166 positive after selection by ficol gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a beta- TCP/HA matrix comparable to the application of 60 mug/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were upregulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Upregulation was detected using immunohistology methods and rtPCR. Dense vascularization was evidenced by CD31 immunohistology staining in all 3 groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with beta-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. PMID: 20636333 [PubMed - as supplied by publisher] | | |
| Neurogenic Drugs and Compounds.
July 21, 2010 at 4:47 AM
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| | Neurogenic Drugs and Compounds. Recent Pat CNS Drug Discov. 2010 Jul 16; Authors: Taupin P The advent of adult neurogenesis and neural stem cell (NSC) research opens new avenues and opportunities for treating neurological diseases and disorders, particularly for the discovery and development of novel drugs. Adult neurogenesis is modulated by a broad range of stimuli, physio- and pathological processes, trophic factors/cytokines and drugs, particularly drugs used for treating neurological diseases and disorders. Hence, adult neurogenesis is the target of drugs used for treating neurological diseases and disorders, such as Alzheimer's disease and depression, and the activities of neurological drugs may be mediated by adult NSCs. Although the contribution and mechanism of adult neurogenesis and newly generated neuronal cells of the adult brain in the activities of neurological drugs remain to be determined, new research is geared toward discovering and developing novel drugs that target specifically adult neurogenesis and the NSCs of the adult brain. Neurogenic drugs may reverse or compensate deficits and impairments associated with neurological diseases and disorders, particularly those associated with the hippocampus. They may have a potential for regenerative medicine and for the treatment of brain tumors. However, limitations in established models and protocols currently used in the drug discovery and development process of these drugs may hinder their potency and specificity. Here, we reviewed and discussed recent patents on neurogenic drugs and compounds, particularly nootropic agents and apigenin and related compounds. PMID: 20636273 [PubMed - as supplied by publisher] | | |
| Microenvironmental targeting of Wnt/beta-catenin signals for hematopoietic stem cell regulation.
July 21, 2010 at 4:47 AM
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| | Microenvironmental targeting of Wnt/beta-catenin signals for hematopoietic stem cell regulation. Expert Opin Biol Ther. 2010 Jul 19; Authors: Oh IH Importance of the field: Microenvironment has emerged as crucial element in the regulation of hematopoietic stem cells (HSCs) in the stem cell niche. Recent studies have demonstrated that Wnt/beta-catenin signals are clearly involved in the stem cell niche, raising the possibility that the hematopoietic microenvironment is a potential target for stem cell therapy. Areas covered in this review: In this review, the biological outcomes of Wnt/beta-catenin signals on HSC activity are summarized in various study models and potential reasons for discrepancies are discussed. Evidence for the microenvironmental targeting of Wnt/beta-catenin signals and studies that verify this concept is summarized. What the reader will gain: We show that distinct effects of Wnt/beta-catenin on HSCs can be caused depending on their target of activation in the hematopoietic microenvironment. We show stromal targeting of Wnt/beta-catenin signals and cross-talk with notch signals in the niche during bone marrow regeneration enhancing the self-renewal of HSCs. Take home message: The identification of stroma-mediated Wnt/beta-catenin effects now allows the integration of discrepancies in previously reported findings and suggests that the stromal targeting of wnt/beta-catenin signals could serve as a potential therapeutic strategy for activating a stem cell niche for the efficient regeneration of HSCs. PMID: 20636187 [PubMed - as supplied by publisher] | | |
| [Effect of the compound of poly lactic-co-glycolic acid and bone marrow stromal cells modified by osteoprotegerin gene on the periodontal regeneration in Beagle dog periodontal defects]
July 21, 2010 at 4:47 AM
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| | [Effect of the compound of poly lactic-co-glycolic acid and bone marrow stromal cells modified by osteoprotegerin gene on the periodontal regeneration in Beagle dog periodontal defects] Hua Xi Kou Qiang Yi Xue Za Zhi. 2010 Jun;28(3):324-9 Authors: Zhou W, Zhao CH, Mei LX OBJECTIVE: To evaluate the effect of the osteoprotegerin (OPG) gene-modified autologous bone marrow stromal cells (BMSCs) on regeneration of periodontal defects, and to provide new experimental evidence to explore the gene therapy for periodontal disease. METHODS: pSecTag2/B-opg was transduced into BMSCs by lipofectamine 2000. The expression of OPG protein in the BMSCs was detected by immunocytochemistry and Western blot. Inverted phase contrast microscope and scanning electron microscopy (SEM) were used to observe the morphology and proliferation of the BMSCs(OPG) on on the surface of the poly lactic-co-glycolic (PLGA). Horizontal alveolar bone defect (4 mmx4 mmx 3 mm) were surgically created in the buccal aspect of the mandibular premolar, and were randomly assigned to receive BMSCs(OPG)-PLGA (cells/material/OPG), BMSCs-PLGA (cells/material), PLGA (material), or root planning only (blank control). The animals were euthanized at 6 weeks post surgery for histological analysis. The height of new alveolar bone and cementum and the formation of new connective tissue were analyzed and compared. All data were statistically analyzed using the q test. RESULTS: The BMSCs transfected by human OPG gene can highly express OPG protein. SEM observations demonstrated that BMSCs(OPG) were able to proliferate and massively colonize on the scaffolds structure. After 6 weeks, the height of new alveolar bone and cementum and the formation of new connective tissue were significantly greater in the experimental group than in the control groups (P < 0.05). CONCLUSION: BMSCs(OPG)-PLGA can significantly promote the regeneration of dog's periodontal bone defects. Gene therapy utilizing OPG may offer the potential for periodontal tissue engineering applications. PMID: 20635668 [PubMed - in process] | | |
| [The experimental study on porous calcium phosphate cement with bone marrow stromal cells for bone tissue engineering]
July 21, 2010 at 4:47 AM
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| | [The experimental study on porous calcium phosphate cement with bone marrow stromal cells for bone tissue engineering] Hua Xi Kou Qiang Yi Xue Za Zhi. 2010 Jun;28(3):315-8 Authors: Wang L, Li YJ, Zhang Y, Pan KF, Huang YL, Liu CS, Jiang XQ OBJECTIVE: To observe the biocompatibility of new biomaterials porous calcium phosphate (CPC) and ectopic bone formation of CPC with bone marrow stromal cells (BMSCs). METHODS: The BMSCs were cultured from Beagle dog and combined with the porous CPC with the best concentration after transfect green fluorescent protein (GFP). The adhesion and growth of BMSCs on CPC were observed under inversion, fluorescence and scanning electron microscopy. The ectopic bone formation were observed at the 8th week after CPC and BMSCs were implanted subcutaneously into nude mice. RESULTS: When BMSCs with CPC were cultured at the 1st day, cells were climbing out from CPC with normal morphology. At the 7th day cells can be seen protruding pseudopods, secretion of matrix. Bone formation could be seen histomorphologically at the 8th week. CONCLUSION: Porous CPC has good biocompatibility and is an ideal scaffold material for bone tissue engineering. PMID: 20635666 [PubMed - in process] | | |
| The influence of ciprofloxacin on hamster ovarian cancer cell line CHO AA8.
July 21, 2010 at 4:47 AM
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| | The influence of ciprofloxacin on hamster ovarian cancer cell line CHO AA8. Acta Pol Pharm. 2010 Jul-Aug;67(4):345-9 Authors: Kloskowski T, Olkowska J, Nazlica A, Drewa T Abstract: Ciprofloxacin is a chinolone antibiotic, which is used mainly in the treatment of urinary tract infections but also in pulmonary tract, prostate gland, bone and bone marrow infection. Ciprofloxacin is also known for its anticancer in vitro properties. In this study hamster ovarian cancer line CHO AA8 was used for evaluation of cytotoxic properties of ciprofloxacin against neoplastic cells. For this purpose we used different concentrations of ciprofloxacin range from 10 to 1000 microg/mL. Cell viability was counted using trypan blue assay. Ciprofloxacin induced morphological changes and decreased viability in a concentration and time dependent manner within CHO AA8 cells. In low concentrations cytotoxic effect of ciprofloxacin is weak only after 24 h incubation. In the highest concentration of ciprofloxacin, after 24, 48 and 72 h incubation only a very small number of living cells (not exceeding 1%) was observed. No living cells were observed after 96 h of incubation times and ciprofloxacin concentrations of 800 and 1000 micrpg/mL. These promising results deserved future studies on chinolones and ovarian cancer. PMID: 20635529 [PubMed - in process] | | |
| Stem cell quiescence in the hippocampal neurogenic niche is associated with elevated transforming growth factor-beta signaling in an animal model of Huntington disease.
July 21, 2010 at 4:47 AM
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| | Stem cell quiescence in the hippocampal neurogenic niche is associated with elevated transforming growth factor-beta signaling in an animal model of Huntington disease. J Neuropathol Exp Neurol. 2010 Jul;69(7):717-28 Authors: Kandasamy M, Couillard-Despres S, Raber KA, Stephan M, Lehner B, Winner B, Kohl Z, Rivera FJ, Nguyen HP, Riess O, Bogdahn U, Winkler J, von Hörsten S, Aigner L Cellular proliferation, differentiation, integration, and survival within the adult neural stem cell niche are altered under pathological conditions, but the molecular cues regulating the biology of this niche are mostly unknown. We examined the hippocampal neural stem cell niche in a transgenic rat model of Huntington disease. In this model, progressive cognitive deficits develop at the age of 9 months, suggesting possible hippocampal dysfunction. We found a disease-associated progressive decline in hippocampal progenitor cell proliferation accompanied by an expansion of the pool of 5-bromo-2-deoxyuridine label-retaining Sox-2-positive quiescent stem cells in the transgenic animals. Increments in quiescent stem cells occurred at the expense of cAMP-responsive element-binding protein-mediated neuronal differentiation and survival. Because elevated levels of transforming growth factor-beta1 (TGF-beta1) impair neural progenitor proliferation, we investigated hippocampal TGF-beta signaling and determined that TGF-beta1 induces the neural progenitors to exit the cell cycle. Although phospho-Smad2, an effector of TGF-beta signaling, is normally absent in subgranular stem cells, it accumulated progressively in Sox2/glial fibrillary acidic protein-expressing cells of the subgranular zone in the transgenic rats. These results indicate that alterations in neurogenesis in transgenic Huntington disease rats occur in successive phases that are associated with increasing TGF-beta signaling. Thus, TGF-beta1 signaling seems to be a crucial modulator of neurogenesis in Huntington disease and may represent a target for future therapy. PMID: 20535034 [PubMed - indexed for MEDLINE] | | |
| Potential therapeutic implications of cancer stem cells in glioblastoma.
July 21, 2010 at 4:47 AM
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| | Potential therapeutic implications of cancer stem cells in glioblastoma. Biochem Pharmacol. 2010 Sep 1;80(5):654-65 Authors: Cheng L, Bao S, Rich JN Glioblastoma is the most common and lethal type of primary brain tumor. Despite recent therapeutic advances in other cancers, the treatment of glioblastomas remains ineffective and essentially palliative. The treatment failure is a result of a number of causes, but we and others have demonstrated that a highly tumorigenic subpopulation of cancer cells called glioblastoma stem cells (GSCs) display relative resistance to radiation and chemotherapy. GSCs also contribute to tumor growth through the stimulation of angiogenesis, which has been shown to be a useful therapeutic target in the treatment of recurrent or progressive malignant gliomas. Cancer stem cells also have been hypothesized as a contributor to systemic metastases. While glioblastomas rarely metastasize beyond the central nervous system, glioblastomas invade into brain structures to prevent surgical cure and GSCs have an extremely invasive phenotype. Collectively, these studies and others suggest that GSCs may be important therapeutic targets not only to achieve cure but even reduce tumor relapse and improve overall survival. Many recent studies suggest that GSCs share core regulatory pathways with normal embryonic and somatic stem cells, but display important distinctions that provide clues into useful treatment targets. The cancer stem cell hypothesis may also modify our approaches in tumor imaging and biomarker development, but clinical validation waits. In this review, we summarize the current understanding of GSC biology with a focus on potential anti-GSC therapies. PMID: 20457135 [PubMed - indexed for MEDLINE] | | |
| Severely damaged kidneys possess multipotent renoprotective stem cells.
July 21, 2010 at 4:47 AM
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| | Severely damaged kidneys possess multipotent renoprotective stem cells. Cytotherapy. 2010 May;12(3):303-12 Authors: Gheisari Y, Nassiri SM, Arefian E, Ahmadbeigi N, Azadmanesh K, Jamali M, Jahanzad I, Zeinali S, Vasei M, Soleimani M BACKGROUND AIMS: Tissue-specific stem cells are a promising target for kidney regeneration, because it has been shown that they play a primary role in kidney repair. Several methods have been developed for the isolation of stem/progenitor cells from healthy kidneys but the existence of these cells in chronically damaged kidneys has not been noticed so far. METHODS: A mouse model of chronic kidney failure was developed by ligation of the left ureter for 5 months, and then isolation of stem cells from this tissue as well as normal kidneys was attempted. RESULTS: We found that multipotent stem cells could be isolated from both types of tissue. In addition, the cells isolated from damaged kidneys showed potential for homing to the site of injury and a renoprotective effect in an animal model of cisplatin-induced nephropathy. CONCLUSIONS: These results show that multipotent renoprotective stem cells exist in severely damaged kidneys, which could be a target for designing new therapies. PMID: 20370347 [PubMed - indexed for MEDLINE] | | |
| Deletion of proapoptotic Puma selectively protects hematopoietic stem and progenitor cells against high-dose radiation.
July 21, 2010 at 4:47 AM
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| | Deletion of proapoptotic Puma selectively protects hematopoietic stem and progenitor cells against high-dose radiation. Blood. 2010 Jun 10;115(23):4707-14 Authors: Shao L, Sun Y, Zhang Z, Feng W, Gao Y, Cai Z, Wang ZZ, Look AT, Wu WS Bone marrow injury is a major adverse side effect of radiation and chemotherapy. Attempts to limit such damage are warranted, but their success requires a better understanding of how radiation and anticancer drugs harm the bone marrow. Here, we report one pivotal role of the BH3-only protein Puma in the radiosensitivity of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs). Puma deficiency in mice confers resistance to high-dose radiation in a hematopoietic cell-autonomous manner. Unexpectedly, loss of one Puma allele is sufficient to confer mice radioresistance. Interestingly, null mutation in Puma protects both primitive and differentiated hematopoietic cells from damage caused by low-dose radiation but selectively protects HSCs and HPCs against high-dose radiation, thereby accelerating hematopoietic regeneration. Consistent with these findings, Puma is required for radiation-induced apoptosis in HSCs and HPCs, and Puma is selectively induced by irradiation in primitive hematopoietic cells, and this induction is impaired in Puma-heterozygous cells. Together, our data indicate that selective targeting of p53 downstream apoptotic targets may represent a novel strategy to protecting HSCs and HPCs in patients undergoing intensive cancer radiotherapy and chemotherapy. PMID: 20360471 [PubMed - indexed for MEDLINE] | | |
| Guidance of olfactory ensheathing cell growth and migration on electrospun silk fibroin scaffolds.
July 21, 2010 at 4:47 AM
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| | Guidance of olfactory ensheathing cell growth and migration on electrospun silk fibroin scaffolds. Cell Transplant. 2010;19(2):147-57 Authors: Shen Y, Qian Y, Zhang H, Zuo B, Lu Z, Fan Z, Zhang P, Zhang F, Zhou C Transplantation of olfactory ensheathing cells (OECs) is a potential treatment for spinal cord injury (SCI). However, this process lacks extracellular matrix guiding cell growth, tissue morphogenesis, and remodeling. In order to solve this problem, we fabricated silk fibroin scaffolds (SFS) with different fiber diameters by electrospinning. The behaviors of OECs on 300 and 1800 nm SFS were studied by analyzing cell morphological feature, distribution, and proliferation. The results showed the 300 nm SFS with good potential to guide OECs growth. Subsequently, the properties of 300 nm SFS were further investigated along with PLL. With 300 nm SFS, the preservation of cell phenotype was confirmed by the presence of cell-specific markers, including nerve growth factor receptor p75 and glial fibrillary acidic protein. And the migration behaviors of OECs were also observed by Leica AF6000. In addition, migration tracks, turning behavior, migration distances, migration speeds, and forward migration indices were calculated. Furthermore, the expression of neurotrophic factors was assayed at transcription and protein levels using RT-PCR and ELISA. All these results indicated the diameter of the fiber played an important role in guiding cell adhesion, growth, and migration in vitro and the 300 nm SFS could be suitable to construct tissue-engineered scaffolds for SCI repair. PMID: 20350362 [PubMed - indexed for MEDLINE] | | |
| FGF signalling as a mediator of lineage transitions--evidence from embryonic stem cell differentiation.
July 21, 2010 at 4:47 AM
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| | FGF signalling as a mediator of lineage transitions--evidence from embryonic stem cell differentiation. J Cell Biochem. 2010 May;110(1):10-20 Authors: Villegas SN, Canham M, Brickman JM The fibroblast growth factor (FGF) signalling pathway is one of the most ubiquitous in biology. It has diverse roles in development, differentiation and cancer. Embryonic stem (ES) cells are in vitro cell lines capable of differentiating into all the lineages of the conceptus. As such they have the capacity to differentiate into derivatives of all three germ layers and to some extent the extra-embryonic lineages as well. Given the prominent role of FGF signalling in early embryonic development, we explore the role of this pathway in early ES cell differentiation towards the major lineages of the embryo. As early embryonic differentiation is intricately choreographed at the level of morphogenetic movement, adherent ES cell culture affords a unique opportunity to study the basic steps in early lineage specification in the absence of ever shifting complex in vivo microenvironments. Thus recent experiments in ES cell differentiation are able to pinpoint specific FGF dependent lineage transitions that are difficult to resolve in vivo. Here we review the role of FGF signalling in early development alongside the ES cell data and suggest that FGF dependent signalling via phospho-Erk activation maybe a major mediator of transitions in lineage specification. PMID: 20336694 [PubMed - indexed for MEDLINE] | | |
| Targeted gene addition to human mesenchymal stromal cells as a cell-based plasma-soluble protein delivery platform.
July 21, 2010 at 4:47 AM
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| | Targeted gene addition to human mesenchymal stromal cells as a cell-based plasma-soluble protein delivery platform. Cytotherapy. 2010 May;12(3):394-9 Authors: Benabdallah BF, Allard E, Yao S, Friedman G, Gregory PD, Eliopoulos N, Fradette J, Spees JL, Haddad E, Holmes MC, Beauséjour CM BACKGROUND AIMS: Gene-modified mesenchymal stromal cells (MSC) provide a promising tool for cell and gene therapy-based applications by potentially acting as a cellular vehicle for protein-replacement therapy. However, to avoid the risk of insertional mutagenesis, targeted integration of a transgene into a 'safe harbor' locus is of great interest. METHODS: We sought to determine whether zinc finger nuclease (ZFN)-mediated targeted addition of the erythropoietin (Epo) gene into the chemokine [C-C motif] receptor 5 (CCR5) gene locus, a putative safe harbor locus, in MSC would result in stable transgene expression in vivo. RESULTS: Whether derived from bone marrow (BM), umbilical cord blood (UCB) or adipose tissue (AT), 30-40% of human MSC underwent ZFN-driven targeted gene addition, as determined by a combination of fluorescence-activated cell sorting (FACS)- and polymerase chain reaction (PCR)-based analyzes. An enzyme-linked immunosorbent assay (ELISA)-based analysis of gene-targeted MSC expressing Epo from the CCR5 locus showed that these modified MSC were found to secrete a significant level of Epo (c. 2 IU/10(6)cells/24 h). NOD/SCID/gammaC mice injected with ZFN-modified MSC expressing Epo exhibited significantly higher hematocrit and Epo plasma levels for several weeks post-injection, compared with mice receiving control MSC. CONCLUSIONS: These data demonstrate that MSC modified by ZFN-driven targeted gene addition may represent a cellular vehicle for delivery of plasma-soluble therapeutic factors. PMID: 20331411 [PubMed - indexed for MEDLINE] | | |
| Mesenchymal stromal cells to treat cardiovascular disease: strategies to improve survival and therapeutic results.
July 21, 2010 at 4:47 AM
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| | Mesenchymal stromal cells to treat cardiovascular disease: strategies to improve survival and therapeutic results. Panminerva Med. 2010 Mar;52(1):27-40 Authors: Noort WA, Feye D, Van Den Akker F, Stecher D, Chamuleau SA, Sluijter JP, Doevendans PA Following myocardial infarction, damage due to ischemia potentially leads to heart failure. Stem cell transplantation has emerged as a potential treatment to repair the injured heart, due to the inherent characteristics of stem cells such as self-renewal, unlimited capacity for proliferation and ability to differentiate to various cell lineages. Most promising results have been reported thus far on mesenchymal stem cells (MSC). Following transplantation in the heart, stem cells are expected to 1) reduce the damage; 2) activate the endogenous regenerative potential of the heart; and 3) participate in the regeneration of the tissue. Until now, the results of intervention with stem cells in animals were promising, but clinical studies have failed to live up to those expectations. Current problems limiting the efficacy of cellular therapy are: 1) limited knowledge on the time and mode of administration; 2) loss of homing receptors on culture-expanded cells as a consequence of the culture conditions; 3) massive cell death in the transplanted graft in the damaged heart, due to the hostile environment, 4) lack of knowledge on MSC behaviour in the heart. Since generally only 1-5% of delivered cells were found to actually engraft within the infarct zone, there is an urgent need for improvement. In animal models, strategies to precondition MSC before transplantation to survive in the damaged heart were applied successfully. These include exposure of cells to physical treatments (hypoxia and heat shock), pharmacological agents, "priming" of cells with growth factors, and genetic modification by over-expression of anti-apoptotic proteins, growth factors or pro-survival genes. To develop the strategy with maximal engraftment, survival and function of cells in the heart is the ultimate challenge for years to come. PMID: 20228724 [PubMed - indexed for MEDLINE] | | |
| Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects.
July 21, 2010 at 4:47 AM
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| | Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects. J Orthop Res. 2010 Aug;28(8):1064-70 Authors: Pei M, Yan Z, Shoukry M, Boyce BM The use of xenogeneic tissues offers many advantages with respect to availability, quality control, and timing of tissue harvest. Our previous study indicated that implantation of premature tissue constructs from allogeneic synovium-derived stem cells (SDSCs) facilitated cartilage tissue regeneration. The present study investigated the feasibility of xenoimplantation of SDSC-based premature tissue constructs for the repair of osteochondral defects. Porcine SDSCs were mixed with fibrin gel, seeded in polyglycolic acid (PGA) scaffolds, and cultured in a rotating bioreactor system supplemented for 1 month with growth factor cocktails. The engineered porcine premature tissues were implanted to repair surgically induced osteochondral defects in the medial femoral condyles of 12 rabbits. Three weeks after surgery, the xenoimplantation group exhibited a smooth, whitish surface while the untreated control remained empty. Surprisingly, 6 months after surgery, the xenoimplantation group displayed some tissue loss while the untreated control group was overgrown with fibrocartilage tissue. In the xenoimplantation group, chronic inflammation was observed in synovial tissue where porcine major histocompatibility complex (MHC) class II antigen positively stained in the engulfed foreign bodies. In addition, porcine source cells also migrated from the implantation site and may have been responsible for the observed loss of glycosaminoglycans (GAGs) underneath surrounding articular cartilage. The histological score was much worse in the xenoimplanted group than in the untreated control. Our study suggested that SDSC-based xenogeneic tissue constructs might cause delayed immune rejection. Xenotransplantation may not be an appropriate approach to repair osteochondral defects. PMID: 20140938 [PubMed - indexed for MEDLINE] | | |
| Statin-induced calcification in human mesenchymal stem cells is cell death related.
July 21, 2010 at 4:47 AM
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| | Statin-induced calcification in human mesenchymal stem cells is cell death related. J Cell Mol Med. 2009 Nov-Dec;13(11-12):4465-73 Authors: Kupcsik L, Meurya T, Flury M, Stoddart M, Alini M Statins are widely used in clinics to lower cholesterol levels. Recently, they have been shown to positively affect bone formation and bone mass in a rat model. The aim of this study was to investigate the effect of pravastatin, simvastatin and lovastatin on the osteoblastic differentiation of human mesenchymal stem cells (MSCs) in vitro. Cell number, alkaline phosphatase (ALP) activity, matrix mineralization and gene expression pattern were determined. Pravastatin did not affect cell differentiation. Simvastatin and lovastatin enhanced bone morphogenetic protein 2 (BMP-2) mRNA levels. In contrast, ALP activity and mRNA levels were suppressed by statins, as well as the DNA content and cell activity (MTT). An increase in apoptotic events was observed at high concentrations of statins, along with high Ca-45 incorporation. Lower concentrations of statins did not increase apoptotic staining, but also failed to induce calcification. When statin-induced calcification did occur, the morphology of the deposits was very different from the conventional nodule formation; the calcium was laid down along the membranes of the rounded cells suggesting it was as a result of cell death. Our results indicate that statins are not able to differentiate human MSCs into osteoblasts and that high concentrations of statins (>1 microM) have a cytotoxic effect. PMID: 19602044 [PubMed - indexed for MEDLINE] | | |
| CD34+ cells augment endothelial cell differentiation of CD14+ endothelial progenitor cells in vitro.
July 21, 2010 at 4:47 AM
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| | CD34+ cells augment endothelial cell differentiation of CD14+ endothelial progenitor cells in vitro. J Cell Mol Med. 2009 Aug;13(8B):2521-33 Authors: Krenning G, van der Strate BW, Schipper M, van Seijen XJ, Fernandes BC, van Luyn MJ, Harmsen MC Neovascularization by endothelial progenitor cells (EPC) for the treatment of ischaemic diseases has been a topic of intense research. The CD34(+) cell is often designated as EPC, because it contributes to repair of ischaemic injuries through neovascularization. However, incorporation of CD34(+) cells into the neovasculature is limited, suggesting another role which could be paracrine. CD14(+) cells can also differentiate into endothelial cells and contribute to neovascularization. However, the low proliferative capacity of CD14(+) cell-derived endothelial cells hampers their use as therapeutic cells. We made the assumption that an interaction between CD34(+) and CD14(+) cells augments endothelial differentiation of the CD14(+) cells. In vitro, the influence of CD34(+) cells on the endothelial differentiation capacity of CD14(+) cells was investigated. Endothelial differentiation was analysed by expression of endothelial cell markers CD31, CD144, von Willebrand Factor and endothelial Nitric Oxide Synthase. Furthermore, we assessed proliferative capacity and endothelial cell function of the cells in culture. In monocultures, 63% of the CD14(+)-derived cells adopted an endothelial cell phenotype, whereas in CD34(+)/CD14(+) co-cultures 95% of the cells showed endothelial cell differentiation. Proliferation increased up to 12% in the CD34(+)/CD14(+) co-cultures compared to both monocultures. CD34-conditioned medium also increased endothelial differentiation of CD14(+) cells. This effect was abrogated by hepatocyte growth factor neutralizing antibodies, but not by interleukin-8 and monocyte chemoattractant protein-1 neutralizing antibodies. We show that co-culturing of CD34(+) and CD14(+) cells results in a proliferating population of functional endothelial cells, which may be suitable for treatment of ischaemic diseases such as myocardial infarction. PMID: 18752636 [PubMed - indexed for MEDLINE] | | |
| A biohybrid artificial lung prototype with active mixing of endothelialized microporous hollow fibers.
July 20, 2010 at 11:47 PM
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| | A biohybrid artificial lung prototype with active mixing of endothelialized microporous hollow fibers. Biotechnol Bioeng. 2010 Jun 15;106(3):490-500 Authors: Polk AA, Maul TM, McKeel DT, Snyder TA, Lehocky CA, Pitt B, Stolz DB, Federspiel WJ, Wagner WR Acute respiratory distress syndrome (ARDS) affects nearly 150,000 patients per year in the US, and is associated with high mortality ( approximately 40%) and suboptimal options for patient care. Mechanical ventilation and extracorporeal membrane oxygenation are limited to short-term use due to ventilator-induced lung injury and poor biocompatibility, respectively. In this report, we describe the development of a biohybrid lung prototype, employing a rotating endothelialized microporous hollow fiber (MHF) bundle to improve blood biocompatibility while MHF mixing could contribute to gas transfer efficiency. MHFs were surface modified with radio frequency glow discharge (RFGD) and protein adsorption to promote endothelial cell (EC) attachment and growth. The MHF bundles were placed in the biohybrid lung prototype and rotated up to 1,500 revolutions per minute (rpm) using speed ramping protocols to condition ECs to remain adherent on the fibers. Oxygen transfer, thrombotic deposition, and EC p-selectin expression were evaluated as indicators of biohybrid lung functionality and biocompatibility. A fixed aliquot of blood in contact with MHF bundles rotated at either 250 or 750 rpm reached saturating pO(2) levels more quickly with increased rpm, supporting the concept that fiber rotation would positively contribute to oxygen transfer. The presence of ECs had no effect on the rate of oxygen transfer at lower fiber rpm, but did provide some resistance with increased rpm when the overall rate of mass transfer was higher due to active mixing. RFGD followed by fibronectin adsorption on MHFs facilitated near confluent EC coverage with minimal p-selectin expression under both normoxic and hyperoxic conditions. Indeed, even subconfluent EC coverage on MHFs significantly reduced thrombotic deposition adding further support that endothelialization enhances, blood biocompatibility. Overall these findings demonstrate a proof-of-concept that a rotating endothelialized MHF bundle enhances gas transfer and biocompatibility, potentially producing safer, more efficient artificial lungs. PMID: 20091735 [PubMed - indexed for MEDLINE] | | | | 
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