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| Muscle-derived stem cells: isolation, characterization, differentiation, and application in cell and gene therapy.
May 25, 2010 at 8:16 AM
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| | Muscle-derived stem cells: isolation, characterization, differentiation, and application in cell and gene therapy. Cell Tissue Res. 2010 May 22; Authors: Wu X, Wang S, Chen B, An X Muscle tissue represents an abundant, accessible, and replenishable source of adult stem cells for cell-based tissue and genetic engineering. A population of cells isolated from muscle exhibits both multipotentiality and self-renewal capabilities. Satellite cells, referred to by many investigators as muscle stem cells, are myogenic precursors that are capable of regenerating muscle and that demonstrate self-renewal properties; however, they are considered to be committed to the myogenic lineage. Muscle-derived stem cells (MDSCs), which may represent a predecessor of the satellite cell, are considered to possess a higher regeneration capacity and to exhibit better cell survival and a broader range of multilineage capabilities. Remarkably, MDSCs are not only able to differentiate into mesodermal cell types including the myogenic, adipogenic, osteogenic, chondrogenic, endothelial, and hematopoietic lineages, but also possess the potential to break germ layer commitme! nt and differentiate into ectodermal lineages including neuron-like cells under certain conditions. This article reviews the current preclinical studies and potential clinical applications of MDSC-mediated gene therapy and tissue-engineering and methods for MDSC isolation, differentiation, and molecular characterization. PMID: 20495827 [PubMed - as supplied by publisher] | | |
| Manserin, a secretogranin II-derived peptide, distributes in the rat endocrine pancreas colocalized with islet-cell specific manner.
May 25, 2010 at 8:16 AM
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| | Manserin, a secretogranin II-derived peptide, distributes in the rat endocrine pancreas colocalized with islet-cell specific manner. Histochem Cell Biol. 2010 May 22; Authors: Tano K, Oyabu A, Tashiro Y, Kamada N, Narita N, Nasu F, Narita M Manserin is a recently characterized 40-amino acid neuropeptide derived from secretogranin II, a protein belonging to the chromogranin family. Although the physiological roles of manserin have not been elucidated to date, manserin has been shown to distribute in not only the brain but also the endocrine system such as the pituitary and adrenal glands, suggesting its role in the endocrine system. The present study aimed to explore the occurrence and distribution of manserin in the rat pancreas using an immunohistochemical technique with a polyclonal antibody against rat manserin. Immunoreactivity for manserin was readily detected in almost whole islets of Langerhans whereas not at all in the exocrine pancreas. Manserin-expressing cells were not colocalized with the glucagon-secreting cells (alpha cells), whereas they colocalized with insulin-secreting cells (beta cells) and somatostatin-secreting cells (delta cells), although their intracellular distribution was di! fferent. These results indicate that manserin, occurring in the endocrine pancreas, may have a potential role in the endocrine system. PMID: 20495819 [PubMed - as supplied by publisher] | | |
| Stem cell-based dental tissue engineering.
May 25, 2010 at 8:16 AM
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| | Stem cell-based dental tissue engineering. ScientificWorldJournal. 2010;10:901-16 Authors: Zivkovic P, Petrovic V, Najman S, Stefanovic V The development of biological and biomaterial sciences profiled tissue engineering as a new and powerful tool for biological replacement of organs. The combination of stem cells and suitable scaffolds is widely used in experiments today, in order to achieve partial or whole organ regeneration. This review focuses on the use of tissue engineering strategies in tooth regeneration, using stem cells and stem cells/scaffold constructs. Although whole tooth regeneration is still not possible, there are promising results. However, to achieve this goal, it is important to understand and further explore the mechanisms underlying tooth development. Only then will we be able to mimic the natural processes with the use of stem cells and tissue engineering techniques. PMID: 20495769 [PubMed - in process] | | |
| Transcriptional regulation of endochondral ossification by HIF-2alpha during skeletal growth and osteoarthritis development.
May 25, 2010 at 8:16 AM
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| | Transcriptional regulation of endochondral ossification by HIF-2alpha during skeletal growth and osteoarthritis development. Nat Med. 2010 May 23; Authors: Saito T, Fukai A, Mabuchi A, Ikeda T, Yano F, Ohba S, Nishida N, Akune T, Yoshimura N, Nakagawa T, Nakamura K, Tokunaga K, Chung UI, Kawaguchi H Chondrocyte hypertrophy followed by cartilage matrix degradation and vascular invasion, characterized by expression of type X collagen (COL10A1), matrix metalloproteinase-13 (MMP-13) and vascular endothelial growth factor (VEGF), respectively, are central steps of endochondral ossification during normal skeletal growth and osteoarthritis development. A COL10A1 promoter assay identified hypoxia-inducible factor-2alpha (HIF-2alpha, encoded by EPAS1) as the most potent transactivator of COL10A1. HIF-2alpha enhanced promoter activities of COL10A1, MMP13 and VEGFA through specific binding to the respective hypoxia-responsive elements. HIF-2alpha, independently of oxygen-dependent hydroxylation, was essential for endochondral ossification of cultured chondrocytes and embryonic skeletal growth in mice. HIF-2alpha expression was higher in osteoarthritic cartilages versus nondiseased cartilages of mice and humans. Epas1-heterozygous deficient mice showed resistance to oste! oarthritis development, and a functional single nucleotide polymorphism (SNP) in the human EPAS1 gene was associated with knee osteoarthritis in a Japanese population. The EPAS1 promoter assay identified RELA, a nuclear factor-kappaB (NF-kappaB) family member, as a potent inducer of HIF-2alpha expression. Hence, HIF-2alpha is a central transactivator that targets several crucial genes for endochondral ossification and may represent a therapeutic target for osteoarthritis. PMID: 20495570 [PubMed - as supplied by publisher] | | |
| Recent advances in liver stem cell therapy.
May 25, 2010 at 8:16 AM
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| | Recent advances in liver stem cell therapy. Curr Opin Gastroenterol. 2010 May 20; Authors: Kisseleva T, Gigante E, Brenner DA PURPOSE OF REVIEW: Patients with liver cirrhosis often require liver transplantation, which remains the only effective treatment of the end-stage cirrhosis. Here we briefly summarize the current concepts in treatment of liver diseases based on the transplantation of intrahepatic liver cells, capable of repopulating the injured liver. These cells include hepatocytes, oval cells (bipotential intrahepatic progenitor cells), bone marrow hematopoietic and mesenchymal stem cells, and induced pluripotent stem (iPS) cells. RECENT FINDINGS: Although liver transplantation remains the only conventional treatment, liver cell transplantation is an experimental procedure which has been successfully used in clinical trials in patients with acute liver failure, chronic liver disease with end-stage cirrhosis. Extraordinary progress has been made in the field of hepatic progenitors and iPS. Liver precursor cells (oval cells) are recognized as bipotential precursor cells in the dama! ged liver. They can rapidly proliferate, change their cellular composition, and differentiate into hepatocytes and cholangiocytes to compensate for the cellular loss and maintain liver homeostasis in animal models of liver injury. Similarly, iPS are somatic cells obtained from patients and differentiated into hepatocytes in vitro. Future studies of iPS are designed to develop of specific conditions to expand and in vitro differentiate somatic cells into functionally mature liver cells. SUMMARY: The current review defines and discusses different populations of hepatic cells which can be potentially used for liver cell transplantation to advance the therapy of hepatic cirrhosis. PMID: 20495456 [PubMed - as supplied by publisher] | | |
| Noninvasive transplantation of bone marrow stromal cells for ischemic stroke: preliminary study with a thermoreversible gelation polymer hydrogel.
May 25, 2010 at 8:16 AM
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| | Noninvasive transplantation of bone marrow stromal cells for ischemic stroke: preliminary study with a thermoreversible gelation polymer hydrogel. Neurosurgery. 2010 Jun;66(6):1140-7 Authors: Osanai T, Kuroda S, Yasuda H, Chiba Y, Maruichi K, Hokari M, Sugiyama T, Shichinohe H, Iwasaki Y OBJECTIVE: Recent studies have indicated that bone marrow stromal cells (BMSCs) have the potential to improve neurological function when transplanted into animal models of cerebral infarct. However, it is still undetermined how the BMSCs should be transplanted to obtain the most efficient therapeutic benefits safely. The aim of this study was to assess whether a thermoreversible gelation polymer (TGP) hydrogel acts as a noninvasive, valuable scaffold in BMSC transplantation for infarct brain. METHODS: The mice were subjected to permanent middle cerebral artery occlusion. Vehicle, BMSC suspension, or the BMSC-TGP construct was transplanted onto the ipsilateral intact neocortex at 7 days after the insult. Neurological symptoms were assessed throughout the experiments. The fate of the transplanted BMSC was examined 8 weeks after transplantation with immunohistochemistry. RESULTS: TGP hydrogel completely disappeared and provoked no inflammation in the host brain. Many! transplanted cells were widely engrafted in the ipsilateral cerebrum, including the dorsal neocortex adjacent to the cerebral infarct in the BMSC-TGP construct-treated mice. Their number was significantly larger than in the BMSC-treated mice. The majority were positive for both NeuN and MAP2 and morphologically simulated the neurons. CONCLUSION: The findings suggest that surgical transplantation of tissue-engineered BMSCs onto the intact neocortex enhances the engraftment of donor cells around the cerebral infarct. These data may be useful in developing a noninvasive but efficient paradigm in neural tissue engineering. TGP hydrogel can be a promising candidate for valuable scaffolds in BMSC transplantation for central nervous system disorders because of its unique biochemical properties. PMID: 20495428 [PubMed - in process] | | |
| The reverse Warburg effect: Glycolysis inhibitors prevent the tumor promoting effects of caveolin-1 deficient cancer associated fibroblasts.
May 25, 2010 at 8:16 AM
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| | The reverse Warburg effect: Glycolysis inhibitors prevent the tumor promoting effects of caveolin-1 deficient cancer associated fibroblasts. Cell Cycle. 2010 May 23;9(10) Authors: Bonuccelli G, Whitaker-Menezes D, Castello-Cros R, Pavlides S, Pestell RG, Fatatis A, Witkiewicz AK, Vander Heiden MG, Migneco G, Chiavarina B, Frank PG, Capozza F, Flomenberg N, Martinez-Outschoorn UE, Sotgia F, Lisanti MP We and others have previously identified a loss of stromal caveolin-1 (Cav-1) in cancer-associated fibroblasts (CAFs) as a powerful single independent predictor of breast cancer patient tumor recurrence, metastasis, tamoxifen-resistance and poor clinical outcome. However, it remains unknown how loss of stromal Cav-1 mediates these effects clinically. To mechanistically address this issue, we have now generated a novel human tumor xenograft model. In this two-component system, nude mice are co-injected with (i) human breast cancer cells (MDA-MB-231), and (ii) stromal fibroblasts (wild-type (WT) versus Cav-1 (-/-) deficient). This allowed us to directly evaluate the effects of a Cav-1 deficiency solely in the tumor stromal compartment. Here, we show that Cav-1-deficient stromal fibroblasts are sufficient to promote both tumor growth and angiogenesis, and to recruit Cav-1 (+) micro-vascular cells. Proteomic analysis of Cav-1-deficient stromal fibroblasts indicates th! at these cells upregulate the expression of glycolytic enzymes, a hallmark of aerobic glycolysis (the Warburg effect). Thus, Cav-1-deficient stromal fibroblasts may contribute towards tumor growth and angiogenesis, by providing energy-rich metabolites in a paracrine fashion. We have previously termed this new idea the "Reverse Warburg Effect". In direct support of this notion, treatment of this xenograft model with glycolysis inhibitors functionally blocks the positive effects of Cav-1-deficient stromal fibroblasts on breast cancer tumor growth. Thus, pharmacologically-induced metabolic restriction (via treatment with glycolysis inhibitors) may be a promising new therapeutic strategy for breast cancer patients that lack stromal Cav-1 expression. We also identify the stromal expression of PKM2 and LDH-B as new candidate biomarkers for the "Reverse Warburg Effect" or "Stromal-Epithelial Metabolic Coupling" in human breast cancers. PMID: 20495363 [PubMed - as supplied by publisher] | | |
| Protein Expression Profiles during Osteogenic Differentiation of Mesenchymal Stem Cells Derived from Human Umbilical Cord Blood.
May 25, 2010 at 8:16 AM
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| | Protein Expression Profiles during Osteogenic Differentiation of Mesenchymal Stem Cells Derived from Human Umbilical Cord Blood. Tohoku J Exp Med. 2010;221(2):141-50 Authors: Kim S, Min WK, Chun S, Lee W, Chung HJ, Choi SJ, Yang SE, Yang YS, Yoo JI Mesenchymal stem cells (MSCs) can potentially differentiate along multiple lineages and be expanded in vitro, making them highly attractive candidates for cell therapy and tissue engineering applications. This study sought to investigate the critical proteins involved in osteogenic differentiation of mesenchymal stem cells derived from umbilical cord blood (UCB-MSCs). MSCs, which were isolated from three different preparations of human UCB, were osteoinduced, and total proteins were extracted from the cells. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was performed on the day (d) of induction d0, and on d2, d7, and d21 of differentiation. The optical density (OD) of each spot was measured, and spots with a mean OD of three cell lines of MSCs that increased > 30 or decreased < 0.1 relative to a previous time point were selected. Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF/MS) was used to identify t! he proteins. Through database searches, the properties and functions of the proteins were investigated and then classified according to the Gene Ontology classification. Among the 308 spots observed in the 2-D gel, 16 proteins with a mean OD ratio > 30, and 20 proteins with a mean OD ratio < 0.1 were identified during the differentiation process. Additionally, the distribution of differentially expressed proteins according to cellular component and molecular function criteria differed depending on whether protein expression increased or decreased during differentiation. The results of this study will comprise an initial proteomic database for UCB-MSCs differentiation. PMID: 20495303 [PubMed - in process] | | |
| The Importance of Elastin to Aortic Development in Mice.
May 25, 2010 at 8:16 AM
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| | The Importance of Elastin to Aortic Development in Mice. Am J Physiol Heart Circ Physiol. 2010 May 21; Authors: Wagenseil JE, Ciliberto CH, Knutsen RH, Levy MA, Kovacs A, Mecham RP Elastin is an essential component of vertebrate arteries that provides elasticity and stores energy during the cardiac cycle. Elastin production in the arterial wall begins mid-gestation but increases rapidly during the last third of human and mouse development, just as blood pressure and cardiac output increase sharply. The aim of this study is to characterize the structure, hemodynamics and mechanics of developing arteries with reduced elastin levels and determine the critical time period where elastin is required in the vertebrate cardiovascular system. Mice that lack elastin (Eln-/-) or have approximately one-half the normal level (Eln+/-) show relatively normal cardiovascular development up to embryonic day 18 as assessed by arterial morphology, left ventricular blood pressure, and cardiac function. Previous work showed that just a few days later, at birth, Eln-/- mice die with high blood pressure and tortuous, stenotic arteries. During this period from E18 t! o birth, Eln+/- mice add extra layers of smooth muscle cells to the vessel wall and have a mean blood pressure 25% higher than wildtype animals. These findings demonstrate that elastin is only necessary for normal cardiovascular structure and function in mice starting in the last few days of fetal development. The large increases in blood pressure during this period may push hemodynamic forces over a critical threshold where elastin becomes required for cardiovascular function. Understanding the interplay between elastin amounts and hemodynamic forces in developing vessels will help design treatments for human elastinopathies and optimize protocols for tissue engineering. PMID: 20495146 [PubMed - as supplied by publisher] | | |
| Regulation of corneal inflammation by neutrophil-dependent cleavage of keratan sulfate proteoglycans as a model for breakdown of the chemokine gradient.
May 25, 2010 at 8:16 AM
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| | Regulation of corneal inflammation by neutrophil-dependent cleavage of keratan sulfate proteoglycans as a model for breakdown of the chemokine gradient. J Leukoc Biol. 2010 May 21; Authors: Carlson EC, Sun Y, Auletta J, Kao WW, Liu CY, Perez VL, Pearlman E Keratocan and lumican are small, leucine-rich repeat KSPGs in the extracellular matrix (ECM) of the mammalian cornea, whose primary role is to maintain corneal transparency. In the current study, we examined the role of these proteoglycans in the breakdown of the chemokine gradient and resolution of corneal inflammation. LPS was injected into the corneal stroma of C57BL/6 mice, and corneal extracts were examined by immunoblot analysis. We found reduced expression of the 52-kD keratocan protein after 6 h and conversely, increased expression of 34/37 kD immunoreactive products. Further, appearance of the 34/37-kD proteins was dependent on neutrophil infiltration to the cornea, as the appearance of these products was coincident with neutrophil infiltration, and the 34/37-kD products were not detected in explanted corneas or in CXCR2(-/-) corneas with deficient neutrophil recruitment. Furthermore, the 34/37-kD products and CXCL1/KC were detected in the anterior chambe! r, into which the corneal stroma drains; and CXCL1/KC was elevated significantly in keratocan(-/- )and lumican(-/-) mice. Together, these findings indicate that the inflammatory response in the cornea is regulated by proteoglycan/CXCL1 complexes, and their diffusion into the anterior chamber is consistent with release of a chemokine gradient and resolution of inflammation. PMID: 20495072 [PubMed - as supplied by publisher] | | |
| [Cerebral plasticity: From bench to bedside in stroke treatment.]
May 25, 2010 at 8:16 AM
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| | [Cerebral plasticity: From bench to bedside in stroke treatment.] Rev Med Interne. 2010 May 20; Authors: Deroide N, Nih LR, Tran Dinh RY, Lévy B, Kubis N It has long been believed that cerebral lesions were irreversible in the adult human brain. However, the spontaneous improvement in functional outcome observed in the following weeks after cerebral ischemia suggests plasticity phenomenons involving postischemic neuronal network reorganization. Regarding the large prevalence of stroke in industrialized countries, and the few available treatments, the understanding of cerebral plasticity has become an important issue but also a potential source of new therapeutic approaches in stroke. Thus, "constraint induced therapy" and repetitive transcranial magnetic stimulation (rTMS) are based on the concept of local but also remote consequences of the ischemic focal lesion. Cell-therapy is based on the capacity of stem cells to respond to hypoxic signals and adapt their phenotype to the host organ, but above all to release cytokines locally and boost endogeneous repair mechanisms. We could consider to perform in the future a! sequential treatment with fibrinolysis, stem cell therapy, repetitive transcranial magnetic stimulation and constraint-induced therapy in the same patient. PMID: 20494495 [PubMed - as supplied by publisher] | | |
| Towards stem cell replacement therapies for Parkinson's disease.
May 25, 2010 at 8:16 AM
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| | Towards stem cell replacement therapies for Parkinson's disease. Biochem Biophys Res Commun. 2010 May 21;396(1):152-156 Authors: Arenas E Current therapeutic approaches for Parkinson's disease (PD) provide symptomatic relief but none of them change the course of disease. There is therefore a clear need for regenerative and cell replacement therapies (CRT). However, CRT faces several important challenges. First, the main symptoms of PD result from the loss of midbrain dopamine (DA) neurons, but other cell types are also affected. Second, transplantation of human ventral midbrain tissue from aborted fetuses has lead to proof of principle that CRT may work, however, it has also pointed out to important patient-, surgery- and cell preparation-related variables, which need to be improved. Third, while some patients have developed dyskinesias and, with time, Lewy bodies in the grafted cells, other patients have experienced remarkable improvement and have been able to stop their medication. Is there a case for PD CRT today? What is the possible contribution of stem cells to CRT? In this review, I will disc! uss what we learned from clinical trials using fetal tissue grafts, recent progress in the development of human stem cell-derived-DA neurons for CRT, and some of the issues that need to be solved in order to develop stem cells as tools for PD CRT. PMID: 20494130 [PubMed - as supplied by publisher] | | |
| Engineering the Crystalline Lens with a Biodegradable or Non-Degradable Scaffold.
May 25, 2010 at 8:16 AM
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| | Engineering the Crystalline Lens with a Biodegradable or Non-Degradable Scaffold. Exp Eye Res. 2010 May 19; Authors: Gwon A, Gruber L Both a biodegradable hyaluronic acid (HA) and a nondegradable polymeric gel were evaluated as scaffolds for tissue engineering the lens in Dutch Belt pigmented and New Zealand white rabbits. Following removal of the crystalline lens through a 2 mm capsulorhexis, a collagen patch or a silicone plug was placed in the capsule bag to seal the capsulotomy. In Part I, a cross-linked HA or cohesive solution of HA was injected into the capsule bag. In Part II, a synthetic polymer (SP) was injected into the capsular bag of one eye and HA followed by SP (HA/SP) was injected into the capsule bag of the opposite eye. At 3 months focal Nd:YAG laser photocoagulation was performed in an attempt to remove some retained HA gel in one eye. Overall the regenerated lenses of the HA gel groups were spherical with excellent cortical structure and clarity and a spherical nucleus of condensed HA gel. In the one eye treated with focal photocoagulation, partial clearing of the retained HA ! gel was noted. In the SP and HA/SP eyes, lens regrowth around the polymer was generally clear in the anterior and peripheral capsule bag and more opacified posterior to the polymeric scaffold. In summary, naturally regenerating lens tissue was directed to grow in a more normal, regular pattern by providing a biodegradable hyaluronic acid scaffold or a nondegradable polymeric optical scaffold. PMID: 20493837 [PubMed - as supplied by publisher] | | |
| Toward delivery of multiple growth factors in tissue engineering.
May 25, 2010 at 8:16 AM
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| | Toward delivery of multiple growth factors in tissue engineering. Biomaterials. 2010 May 19; Authors: Chen FM, Zhang M, Wu ZF Inspired by physiological events that accompany the "wound healing cascade", the concept of developing a tissue either in vitro or in vivo has led to the integration of a wide variety of growth factors (GFs) in tissue engineering strategies in an effort to mimic the natural microenvironments of tissue formation and repair. Localised delivery of exogenous GFs is believed to be therapeutically effective for replication of cellular components involved in tissue development and the healing process, thus making them important factors for tissue regeneration. However, any treatment aiming to mimic the critical aspects of the natural biological process should not be limited to the provision of a single GF, but rather should release multiple therapeutic agents at an optimised ratio, each at a physiological dose, in a specific spatiotemporal pattern. Despite several obstacles, delivery of more than one GF at rates mimicking an in vivo situation has promising potential for ! the clinical management of severely diseased tissues. This article summarises the concept of and early approaches toward the delivery of dual or multiple GFs, as well as current efforts to develop sophisticated delivery platforms for this ambitious purpose, with an emphasis on the application of biomaterials-based deployment technologies that allow for controlled spatial presentation and release kinetics of key biological cues. Additionally, the use of platelet-rich plasma or gene therapy is addressed as alternative, easy, cost-effective and controllable strategies for the release of high concentrations of multiple endogenous GFs, followed by an update of the current progress and future directions of research utilising release technologies in tissue engineering and regenerative medicine. PMID: 20493521 [PubMed - as supplied by publisher] | | |
| Purified Hematopoietic Stem Cell Transplantation: The Next Generation of Blood and Immune Replacement.
May 25, 2010 at 8:16 AM
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| | Purified Hematopoietic Stem Cell Transplantation: The Next Generation of Blood and Immune Replacement. Immunol Allergy Clin North Am. 2010 May;30(2):159-171 Authors: Czechowicz A, Weissman IL Replacement of disease-causing stem cells with healthy ones has been achieved clinically via hematopoietic cell transplantation (HCT) for the last 40 years, as a treatment modality for a variety of cancers and immunodeficiencies with moderate, but increasing, success. This procedure has traditionally included transplantation of mixed hematopoietic populations that include hematopoietic stem cells (HSC) and other cells, such as T cells. This article explores and delineates the potential expansion of this technique to treat a variety of inherited diseases of immune function, the current barriers in HCT and pure HSC transplantation, and the up-and-coming strategies to combat these obstacles. PMID: 20493393 [PubMed - as supplied by publisher] | | |
| Functional tissue engineering of ligament healing.
May 25, 2010 at 8:16 AM
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| | Functional tissue engineering of ligament healing. Sports Med Arthrosc Rehabil Ther Technol. 2010 May 21;2(1):12 Authors: Hsu SL, Liang R, Woo SL ABSTRACT: Ligaments and tendons are dense connective tissues that are important in transmitting forces and facilitating joint articulation in the musculoskeletal system. Their injury frequency is high especially for those that are functionally important, like the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) of the knee as well as the glenohumeral ligaments and the rotator cuff tendons of the shoulder. Because the healing responses are different in these ligaments and tendons after injury, the consequences and treatments are tissue- and site-specific. In this review, we will elaborate on the injuries of the knee ligaments as well as using functional tissue engineering (FTE) approaches to improve their healing. Specifically, the ACL of knee has limited capability to heal, and results of non-surgical management of its midsubstance rupture have been poor. Consequently, surgical reconstruction of the ACL is regularly performed to gain knee stab! ility. However, the long-term results are not satisfactory besides the numerous complications accompanied with the surgeries. With the rapid development of FTE, there is a renewed interest in revisiting ACL healing. Approaches such as using growth factors, stem cells and scaffolds have been widely investigated. In this article, the biology of normal and healing ligaments is first reviewed, followed by a discussion on the issues related to the treatment of ACL injuries. Afterwards, current promising FTE methods are presented for the treatment of ligament injuries, including the use of growth factors, gene delivery, and cell therapy with a particular emphasis on the use of ECM bioscaffolds. The challenging areas are listed in the future direction that suggests where collection of energy could be placed in order to restore the injured ligaments and tendons structurally and functionally. PMID: 20492676 [PubMed - as supplied by publisher] | | |
| The effect of clinical experience on dentine bonding effectiveness: students versus trained dentists.
May 25, 2010 at 8:16 AM
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| | The effect of clinical experience on dentine bonding effectiveness: students versus trained dentists. J Oral Rehabil. 2010 May 21; Authors: Ueda M, Mine A, DE Munck J, Hakogi T, VAN Meerbeek B, Kuboki T Summary Clinical successful application of dentine adhesives depends not only on material-related but also on operator-related factors. The purpose of this study was to evaluate the dentine bonding effectiveness of a self-etch composite cement applied by operators with or without clinical experience under well-standardized, randomized and blind conditions. Forty-eight bovine dentine surfaces were randomly divided into two groups. The first group consisted of eight dental students with no clinical experience at all, and the second group consisted of eight dentists with extensive experience in adhesive dentistry (mean experience of 11.4 years). Next, a 4-mm-diameter stainless steel rod (SUS-304) was bonded to the dentine surface using Panavia Fluoro cement (Kuraray Medical Inc., Tokyo, Japan). After application procedures, the specimens were randomized and shear bond-strength measurements were performed by a single blinded operator. Mann-Whitney U test was used to d! etermine statistical differences in bond strength between the two groups, and Kruskal-Wallis was used to determine statistical difference between the student and dentist groups. The means and standard deviations of bond strength were 11.5 +/- 8.1 MPa for the student group and 7.1 +/- 4.3 MPa for the dentist group, respectively. The bond strength of the student group was significantly higher than that of the dentist group. However, the variability in bond strength was significantly higher in the student group, and some specimens failed prior to actual testing (included as 0 MPa). Clinical experience did not have a positive effect on the bonding effectiveness of the self-etch composite cement to dentine. PMID: 20492442 [PubMed - as supplied by publisher] | | |
| Mesenchymal Stem Cells Overexpressing Ephrin-B2 Rapidly Adopt an Early Endothelial Phenotype with Simultaneous Reduction of Osteogenic Potential.
May 25, 2010 at 8:16 AM
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| | Mesenchymal Stem Cells Overexpressing Ephrin-B2 Rapidly Adopt an Early Endothelial Phenotype with Simultaneous Reduction of Osteogenic Potential. Tissue Eng Part A. 2010 May 22; Authors: Duffy GP, D'Arcy S, Ahsan T, Nerem RM, O'Brien T, Barry F Restoration of the vascular supply to ischemic tissues is of high clinical relevance, and proangiogenic therapies aim to reduce morbidity and mortality rates associated with the onset of cardiovascular disease. Stem cell therapy has been proposed as a potentially useful proangiogenic therapy. Mesenchymal stem cells (MSCs) have been shown to be proangiogenic and produce a number of cytokines involved in vessel development and maturation. Preclinical studies have reported increased angiogenesis after MSC delivery to the heart, and similar outcomes have been reported in recent clinical trials. Stem-cell-mediated neovascularization has been augmented by genetic modification with overexpression of angiogenic cytokines, including vascular endothelial growth factor (VEGF) and platelet-derived growth factor, showing promising results. In this study we aimed to enhance the proangiogenic capability of MSCs. MSCs were genetically modified to overexpress a versatile molecule,! Ephrin-B2, involved in tissue morphogenesis and vascular development to enhance inherent neovascularization potential. Using nucleofection, Ephrin-B2 was transiently overexpressed on the cell surface of MSCs to recapitulate embryonic signaling and promote neovascularization. Ephrin-B2-expressing MSCs adopted an early endothelial phenotype under endothelial cell culture conditions increasing expression of von Willebrand factor and VEGF-Receptor 2. The cells had an increased ability to form vessel-like structures, produce VEGF, and incorporate into newly formed endothelial cell structures. These data indicate that MSCs expressing Ephrin-B2 represent a novel proangiogenic cell source to promote neovascularization in ischemic tissues. PMID: 20491587 [PubMed - as supplied by publisher] | | |
| Human dental pulp cells exhibit bone cell-like responsiveness to fluid shear stress.
May 25, 2010 at 8:16 AM
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| | Human dental pulp cells exhibit bone cell-like responsiveness to fluid shear stress. Cytotherapy. 2010 May 21; Authors: Kraft DC, Bindslev DA, Melsen B, Klein-Nulend J Abstract Background aims. For engineering bone tissue to restore, for example, maxillofacial defects, mechanosensitive cells are needed that are able to conduct bone cell-specific functions, such as bone remodelling. Mechanical loading affects local bone mass and architecture in vivo by initiating a cellular response via loading-induced flow of interstitial fluid. After surgical removal of ectopically impacted third molars, human dental pulp tissue is an easily accessible and interesting source of cells for mineralized tissue engineering. The aim of this study was to determine whether human dental pulp-derived cells (DPC) are responsive to mechanical loading by pulsating fluid flow (PFF) upon stimulation of mineralization in vitro. Methods. Human DPC were incubated with or without mineralization medium containing differentiation factors for 3 weeks. Cells were subjected to 1-h PFF (0.7 +/- 0.3Pa, 5Hz) and the response was quantified by measuring nitric oxide (NO) ! and prostaglandin E(2) (PGE(2)) production, and gene expression of cyclooxygenase (COX)-1 and COX-2. Results. We found that DPC are intrinsically mechanosensitive and, like osteogenic cells, respond to PFF-induced fluid shear stress. PFF stimulated NO and PGE(2) production, and up-regulated COX-2 but not COX-1 gene expression. In DPC cultured under mineralizing conditions, the PFF-induced NO, but not PGE(2), production was significantly enhanced. Conclusions. These data suggest that human DPC, like osteogenic cells, acquire responsiveness to pulsating fluid shear stress in mineralizing conditions. Thus DPC might be able to perform bone-like functions during mineralized tissue remodeling in vivo, and therefore provide a promising new tool for mineralized tissue engineering to restore, for example, maxillofacial defects. PMID: 20491534 [PubMed - as supplied by publisher] | | |
| Nanofiber Assembly by Rotary Jet-Spinning.
May 25, 2010 at 8:16 AM
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| | Nanofiber Assembly by Rotary Jet-Spinning. Nano Lett. 2010 May 21; Authors: Badrossamay MR, McIlwee HA, Goss JA, Parker KK High-voltage electrical fields and low production rate limit electrospinning, the electrical charging of polymer liquids, as a means of nanofiber fabrication. Here, we show a facile method of fabrication of aligned three-dimensional nanofiber structures by utilizing high-speed, rotating polymer solution jets to extrude fibers. Termed rotary jet-spinning, fiber morphology, diameter, and web porosity can be controlled by varying nozzle geometry, rotation speed, and polymer solution properties. We demonstrate the utility of this technique for tissue engineering by building anisotropic arrays of biodegradable polymer fibers and seeding the constructs with neonatal rat ventricular cardiomyocytes. The myocytes used the aligned fibers to orient their contractile cytoskeleton and to self-organize into a beating, multicellular tissue that mimics the laminar, anisotropic architecture of the heart muscle. This technique may prove advantageous for building uniaxially aligned ! nanofiber structures for polymers which are not amenable to fabrication by electrospinning. PMID: 20491499 [PubMed - as supplied by publisher] | | |
| Therapeutic applications of hyaluronan.
May 25, 2010 at 8:16 AM
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| | Therapeutic applications of hyaluronan. Mol Biosyst. 2010 Mar;6(3):437-43 Authors: Gaffney J, Matou-Nasri S, Grau-Olivares M, Slevin M Hyaluronan (HA), a multifunctional, high molecular weight glycosaminoglycan, is a component of the majority of extracellular matrices. HA is synthesised in a unique manner by a family of hyaluronan synthases, degraded by hyaluronidases and exerts a biological effect by binding to families of cellular receptors, the hyaladhedrins. Receptor binding activates signal pathways in endothelial cells leading to proliferation, migration and differentiation collectively termed angiogenesis. HA and associated enzymes are implicated in the aetiology of cardiovascular disease and cancer and manipulation of HA expression offers a therapeutic target. HA microspheres have been developed as drug delivery agents to deliver HA to sites of disease and also in diagnosis. In this review we discuss some of the recent therapeutic applications of hyaluronan in tissue repair, as a drug delivery system and the synthesis, application and delivery of hyaluronan nanoparticles to target drugs t! o sites of disease. PMID: 20174672 [PubMed - indexed for MEDLINE] | | |
| Intact fetal ovarian cord formation promotes mouse oocyte survival and development.
May 25, 2010 at 8:16 AM
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| | Intact fetal ovarian cord formation promotes mouse oocyte survival and development. BMC Dev Biol. 2010;10:2 Authors: Nicholas CR, Haston KM, Pera RA BACKGROUND: Female reproductive potential, or the ability to propagate life, is limited in mammals with the majority of oocytes lost before birth. In mice, surviving perinatal oocytes are enclosed in ovarian follicles for subsequent oocyte development and function in the adult. Before birth, fetal germ cells of both sexes develop in clusters, or germline cysts, in the undifferentiated gonad. Upon sex determination of the fetal gonad, germ cell cysts become organized into testicular or ovarian cord-like structures and begin to interact with gonadal somatic cells. Although germline cysts and testicular cords are required for spermatogenesis, the role of cyst and ovarian cord formation in mammalian oocyte development and female fertility has not been determined. RESULTS: Here, we examine whether intact fetal ovarian germ and somatic cell cord structures are required for oocyte development using mouse gonad re-aggregation and transplantation to disrupt gonadal organiz! ation. We observed that germ cells from disrupted female gonad prior to embryonic day e13.5 completed prophase I of meiosis but did not survive following transplantation. Furthermore, re-aggregated ovaries from e13.5 to e15.5 developed with a reduced number of oocytes. Oocyte loss occurred before follicle formation and was associated with an absence of ovarian cord structure and ovary disorganization. However, disrupted ovaries from e16.5 or later were resistant to the re-aggregation impairment and supported robust oocyte survival and development in follicles. CONCLUSIONS: Thus, we demonstrate a critical window of oocyte development from e13.5 to e16.5 in the intact fetal mouse ovary, corresponding to the establishment of ovarian cord structure, which promotes oocyte interaction with neighboring ovarian somatic granulosa cells before birth and imparts oocytes with competence to survive and develop in follicles. Because germline cyst and ovarian cord structures are conserved! in the human fetal ovary, the identification of genetic compo! nents an d molecular mechanisms of pre-follicle stage germ and somatic cell structures may be important for understanding human female infertility. In addition, this work provides a foundation for development of a robust fetal ovarian niche and transplantation based system to direct stem cell-derived oocyte differentiation as a potential therapeutic strategy for the treatment of infertility. PMID: 20064216 [PubMed - indexed for MEDLINE] | | |
| Evaluation of early tissue reactions after lumbar intertransverse process fusion using CT in a rabbit.
May 25, 2010 at 8:16 AM
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| | Evaluation of early tissue reactions after lumbar intertransverse process fusion using CT in a rabbit. Skeletal Radiol. 2010 Apr;39(4):369-73 Authors: Shinbo J, Mainil-Varlet P, Watanabe A, Pippig S, Koener J, Anderson SE OBJECTIVE: The objective of the study was to evaluate tissue reactions such as bone genesis, cartilage genesis and graft materials in the early phase of lumbar intertransverse process fusion in a rabbit model using computed tomography (CT) imaging with CT intensity (Hounsfield units) measurement, and to compare these data with histological results. MATERIALS AND METHODS: Lumbar intertransverse process fusion was performed on 18 rabbits. Four graft materials were used: autograft bone (n = 3); collagen membrane soaked with recombinant human bone morphogenetic protein-2 (rhBMP-2) (n = 5); granular calcium phosphate (n = 5); and granular calcium phosphate coated with rhBMP-2 (n = 5). All rabbits were euthanized 3 weeks post-operatively and lumbar spines were removed for CT imaging and histological examination. RESULTS: Computed tomography imaging demonstrated that each fusion mass component had the appropriate CT intensity range. CT also showed the different distribut! ions and intensities of bone genesis in the fusion masses between the groups. Each component of tissue reactions was identified successfully on CT images using the CT intensity difference. Using CT color mapping, these observations could be easily visualized, and the results correlated well with histological findings. CONCLUSIONS: The use of CT intensity is an effective approach for observing and comparing early tissue reactions such as newly synthesized bone, newly synthesized cartilage, and graft materials after lumbar intertransverse process fusion in a rabbit model. PMID: 19554327 [PubMed - indexed for MEDLINE] | | |
| A tissue adhesives evaluated in vitro and in vivo analysis.
May 25, 2010 at 3:16 AM
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| | A tissue adhesives evaluated in vitro and in vivo analysis. J Biomed Mater Res A. 2010 Jul;94(1):326-32 Authors: Mo X, Iwata H, Ikada Y In this study, three kinds of two-component adhesive glues were prepared, namely, gel-dext glue made from modified gelatin and dextran, gel-HES glue made from modified gelatin and hydroxyethyl starch (HES), and chit-dext glue made from chitosan and modified dextran. Upon mixing the two-component solution together crosslinking occurred and a gel formed in several seconds, which would seal the wound tissue and stop the bleeding. The adhesive ability of those three prepared glues was evaluated in vitro and in vivo separately by measuring the bonding strength to two piece of porcine skin and the adhesive strength after sealing the skin incisions on the back of rat. Fibrin glue was used as comparing. Gel-dext glue and gel-HES glue shown higher bonding strength and adhesive strength than chit-dext glue and fibrin glue. Histology test of incision tissues given by both HE and MTC methods, the former shown that gel-dext and gel-HES glues, like fibrin glue, have only normal! initial inflammation to skin tissue, which almost disappear from 9 days but chit-dext glue seams have heaver inflammation, which may last to 12 days; the later shown gel-dext and gel-HES glues similar to fibrin glue, can heal the wound fast than that of chit-dext glue. The hemostatic ability for gel-HES glue was also tested on a cut liver of rat, which depend on the gel formation speed when the two-composite solutions were mixed together. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010. PMID: 20496438 [PubMed - in process] | | |
| A proteomic approach for identifying cellular proteins interacting with erythropoietin in recombinant Chinese hamster ovary cells.
May 25, 2010 at 3:16 AM
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| | A proteomic approach for identifying cellular proteins interacting with erythropoietin in recombinant Chinese hamster ovary cells. Biotechnol Prog. 2010 Jan;26(1):246-51 Authors: Kim JY, Kim YG, Baik JY, Joo EJ, Kim YH, Lee GM Identification of the cellular proteins interacting with incompletely folded and unfolded forms of erythropoietin (EPO) in recombinant CHO (rCHO) cells leads to better insight into the possible genetic manipulation approaches for increasing EPO production. To do so, a pull-down assay was performed with dual-tagged (N-terminal GST- and C-terminal hexahistidine-tagged) EPO expressed in E. coli as bait proteins and cell lysates of rCHO cells (DG44) as prey proteins. Cellular proteins interacting with dual-tagged EPO were then resolved by two-dimensional gel electrophoresis (2DE) and identified by MALDI-TOF MS/MS. A total of 27 protein spots including glucose-regulated protein 78 (GRP78) were successfully identified. Western blot analysis of GRP78 confirmed the results of the MS analyses. Taken together, a pull-down assay followed by a proteomic approach is found to be an efficient means to identify cellular proteins interacting with foreign protein in rCHO cells. PMID: 19918894 [PubMed - indexed for MEDLINE] | | | | 
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