|
| Stem Cell Directors Postpone Action on Troubled Appeals Process
July 20, 2010 at 7:17 PM
|
| Directors of the California stem cell agency today delayed action on moves to reshape the "broken" grant appeal process at CIRM.
In response to a query about the outcome of the directors' Science Subcommittee, Don Gibbons, chief of CIRM communications, said,
"A lengthy discussion resulted in agreement to continue the discussion rather than take action at this time. It was generally agreed that | | |
| Biopolitical Times Questions Rationale for Future CIRM Funding
July 20, 2010 at 2:31 PM
|
| The case that California stem cell Chairman Robert Klein is trying to make for more funding for the $3 billion research effort rings hollow, according to the Center for Genetics and Society.
Writing on the group's Biopolitical Times blog, Jesse Reynolds, the Berkeley center's project director on biotechnology accountability, said that another ballot measure for stem cell research would fail. He | | |
| Transplantation of marrow-derived cardiac stem cells carried in designer self-assembling peptide nanofibers improves cardiac function after myocardial infarction.
July 20, 2010 at 11:55 AM
|
| | 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] | | |
| Microenvironmental targeting of Wnt/beta-catenin signals for hematopoietic stem cell regulation.
July 20, 2010 at 11:55 AM
|
| | 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] | | |
| Electrospun poly(D: /L: -lactide-co-L: -lactide) hybrid matrix: a novel scaffold material for soft tissue engineering.
July 20, 2010 at 8:02 AM
|
| | 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] | | |
| Spinal Effects of the Fesoterodine Metabolite 5-Hydroxymethyl Tolterodine and/or Doxazosin in Rats With or Without Partial Urethral Obstruction.
July 20, 2010 at 8:02 AM
|
| | 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 effect of a slow mode of BMP-2 delivery on the inflammatory response provoked by bone-defect-filling polymeric scaffolds.
July 20, 2010 at 8:02 AM
|
| | 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 20, 2010 at 8:02 AM
|
| | 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] | | |
| Derivation efficiency, cell proliferation, freeze-thaw survival, stem-cell properties and differentiation of human Wharton's jelly stem cells.
July 20, 2010 at 8:02 AM
|
| | 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] | | |
| Immediate and gradual gene expression changes in telomerase over-expressing fibroblasts.
July 20, 2010 at 8:02 AM
|
| | 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] | | |
| Isolation of short peptide fragments from alpha-synuclein fibril core identifies a residue important for fibril nucleation: A possible implication for diagnostic applications.
July 20, 2010 at 8:02 AM
|
| | 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 20, 2010 at 8:02 AM
|
| | 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] | | |
| Neurogenic Drugs and Compounds.
July 20, 2010 at 8:02 AM
|
| | 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 20, 2010 at 8:02 AM
|
| | 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] | | |
| Mesenchymal stromal cells to treat cardiovascular disease: strategies to improve survival and therapeutic results.
July 20, 2010 at 8:02 AM
|
| | 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] | | |
| Preparation, fabrication and biocompatibility of novel injectable temperature-sensitive chitosan/glycerophosphate/collagen hydrogels.
July 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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] | | |
| The regulation of phenotype of cultured tenocytes by microgrooved surface structure.
July 20, 2010 at 6:29 AM
|
| | 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] | | |
| Availability of Adipose-Derived Stem Cells in Patients Undergoing Vascular Surgical Procedures.
July 20, 2010 at 6:29 AM
|
| | 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] | | |
| Engineering more than a cell: vascularization strategies in tissue engineering.
July 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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] | | |
| Immediate and gradual gene expression changes in telomerase over-expressing fibroblasts.
July 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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] | | |
| Bone tissue engineering with human stem cells.
July 20, 2010 at 6:29 AM
|
| | 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 20, 2010 at 6:29 AM
|
| | 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] | | |
| [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 20, 2010 at 6:29 AM
|
| | [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 20, 2010 at 6:29 AM
|
| | [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 20, 2010 at 6:29 AM
|
| | 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] | | |
| Guidance of olfactory ensheathing cell growth and migration on electrospun silk fibroin scaffolds.
July 20, 2010 at 6:29 AM
|
| | 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] | | |
| Statin-induced calcification in human mesenchymal stem cells is cell death related.
July 20, 2010 at 6:29 AM
|
| | 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] | | |
| CIRM Seeks Communications Coordinator
July 20, 2010 at 1:12 AM
|
| The California stem cell agency is still looking for a "communications outreach coordinator" to help beef up its public relations efforts.
The agency has re-posted the RFP for the $85,000, 12-month job after apparently not being satisfied with the earlier round of applicants. The part-time position also includes a $10,000 travel budget. The winning applicant will be expected to work 20 to 30 | | | | 
| This email was sent to regenmd@gmail.com. Account Login
Don't want to receive this feed any longer? Unsubscribe here
This email was carefully delivered by Feed My Inbox. 230 Franklin Road Suite 814 Franklin, TN 37064 | |
No comments:
Post a Comment