| |  | | | | | | | | | | | | | | | |  | | | | | | | | | | | | | | | | | | | | | | | | Cardiac Involvement in Patients With Hematologic Malignancies. J Investig Med. 2010 Jul 30; Authors: Allegra A, Alonci A, Russo S, Cannavò A, Penna G, D'Angelo A, Bellomo G, Musolino C Authors have reviewed literature about the management of patients with cardiologic disease occurring secondary to hematologic pathology itself or its therapy, with a focus on infiltration of myocardium in acute and chronic leukemia, lymphoma, multiple myeloma, and hypereosinophilic syndrome. Moreover, they evaluated chemotherapy-associated toxicity, particularly for new drugs such as monoclonal antibody therapy, tyrosine kinase inhibitors, arsenic trioxide, bortezomib, and epigenetic therapy. In fact, cardiac toxicity may range from asymptomatic subclinical abnormalities, such as electrocardiographic changes and left ventricular ejection decline, to life-threatening events and lead to chemotherapy dose reduction and delay and, in some cases, for patients with severe side effects, discontinuation of treatment.Finally, they discussed on the identification of early markers of cardiac injury and on cardiac stem cell therapy as a promising approach to facilitate myocardial regeneration. PMID: 20683345 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Numerical assessment on the effective mechanical stimuli for matrix-associated metabolism in chondrocyte-seeded constructs. J Tissue Eng Regen Med. 2010 Aug 4; Authors: Tasci A, Ferguson SJ, Büchler P The self-regeneration capacity of articular cartilage is limited, due to its avascular and aneural nature. Loaded explants and cell cultures demonstrated that chondrocyte metabolism can be regulated via physiologic loading. However, the explicit ranges of mechanical stimuli that correspond to favourable metabolic response associated with extracellular matrix (ECM) synthesis are elusive. Unsystematic protocols lacking this knowledge produce inconsistent results. This study aims to determine the intrinsic ranges of physical stimuli that increase ECM synthesis and simultaneously inhibit nitric oxide (NO) production in chondrocyte-agarose constructs, by numerically re-evaluating the experiments performed by Tsuang et al. (2008). Twelve loading patterns were simulated with poro-elastic finite element models in ABAQUS. Pressure on solid matrix, von Mises stress, maximum principle stress and pore pressure were selected as intrinsic mechanical stimuli. Their development rates and magnitudes at the steady state of cyclic loading were calculated with MATLAB at the construct level. Concurrent increase in glycosaminoglycan and collagen was observed at 2300 Pa pressure and 40 Pa/s pressure rate. Between 0-1500 Pa and 0-40 Pa/s, NO production was consistently positive with respect to controls, whereas ECM synthesis was negative in the same range. A linear correlation was found between pressure rate and NO production (R = 0.77). Stress states identified in this study are generic and could be used to develop predictive algorithms for matrix production in agarose-chondrocyte constructs of arbitrary shape, size and agarose concentration. They could also be helpful to increase the efficacy of loading protocols for avascular tissue engineering. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20684030 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mutations in GDF5 presenting as semi-dominant Brachydactyly A1. Hum Mutat. 2010 Aug 3; Authors: Byrnes AM, Racacho L, Nikkel SM, Xiao F, Macdonald H, Underhill TM, Bulman DE Brachydactyly A1 (BDA1) is an autosomal dominant disorder characterized by shortness of all middle phalanges of the hands and toes, shortness of the proximal phalanges of the first digit, and short stature. Missense mutations in the Indian Hedgehog gene (IHH) are known to cause BDA1, and a second locus has been mapped to chromosome 5p. In a consanguineous French Canadian kindred with BDA1, both IHH and the 5p locus were excluded. Microsatellites flanking GDF5 on chromosome 20q were found to cosegregate with the disease. Sequencing of the GDF5 coding region revealed that a mildly affected individual in the family was heterozygous and that all of the severely affected individuals were homozygous for a novel missense c.1195C>T mutation that predicts a p.Arg399Cys substitution at a highly conserved amino acid. Functional analysis demonstrated that while the p.Arg399Cys mutant is able to stimulate chondrogenesis, it is much less effective than wild-type GDF5. This data confirms genetic heterogeneity in BDA1, demonstrates that mutations upstream of IHH can result in BDA1 and shows that BDA1 can result from semi-dominant mutations in GDF5. (c) 2010 Wiley-Liss, Inc. PMID: 20683927 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Active DNA demethylation: many roads lead to Rome. Nat Rev Mol Cell Biol. 2010 Aug 4; Authors: Wu SC, Zhang Y DNA methylation is one of the best-characterized epigenetic modifications and has been implicated in numerous biological processes, including transposable element silencing, genomic imprinting and X chromosome inactivation. Compared with other epigenetic modifications, DNA methylation is thought to be relatively stable. Despite its role in long-term silencing, DNA methylation is more dynamic than originally thought as active DNA demethylation has been observed during specific stages of development. In the past decade, many enzymes have been proposed to carry out active DNA demethylation and growing evidence suggests that, depending on the context, this process may be achieved by multiple mechanisms. Insight into how DNA methylation is dynamically regulated will broaden our understanding of epigenetic regulation and have great implications in somatic cell reprogramming and regenerative medicine. PMID: 20683471 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Design of a Bioartificial Pancreas+ J Investig Med. 2010 Jul 30; Authors: Opara EC, Mirmalek-Sani SH, Khanna O, Moya ML, Brey EM INTRODUCTION:: In type 1 diabetes, the beta-cells that secrete insulin have been destroyed such that daily exogenous insulin administration is required for the control of blood glucose in individuals with the disease. After the development of reliable techniques for the isolation of islets from the human pancreas, islet transplantation has emerged as a therapeutic option, albeit for only a few selected patients largely because there are not enough islets for the millions of patients requiring the treatment, and there is also the need to use immunosuppressive drugs to prevent transplant rejection. In 1980, the concept of islet immunoisolation by microencapsulation was introduced as a technique to overcome these 2 major barriers to islet transplantation. Microencapsulation of islets and transplantation in the peritoneal cavity was then described as a bioartificial pancreas. However, it is difficult to retrieve encapsulated islets transplanted in the peritoneal cavity, thus making it difficult to meet all the criteria for a bioartificial pancreas. A new design of a bioartificial pancreas comprising islets co-encapsulated with angiogenic protein in permselective multilayer alginate-poly-L-ornithine-alginate microcapsules and transplanted in an omentum pouch is described in this paper. MATERIALS AND METHODS:: The multilayer alginate-poly-L-ornithine-alginate microcapsules are made with ultrapure alginate using poly-L-ornithine as a semipermeable membrane separating the 2 alginate layers. The inner alginate layer is used to encapsulate the islets, and the outer layer is used to encapsulate angiogenic protein, which would induce neovascularization around the graft within the omentum pouch. RESULTS:: In in vitro studies, we found that both the wild-type and the heparin-binding growth-associated molecule (HBGAM)-fibroblast growth factor-1 chimera can be encapsulated and released in a controlled and sustained manner from the outer alginate layer with a mean diameter in the range of 113 to 164 microm when 1.25% high guluronic acid alginate is used to formulate this outer layer. DISCUSSION:: We are currently performing in vivo experiments to determine the ability of angiogenic proteins released from this outer layer to induce neovascularization around the grafts in the omentum pouch. We will subsequently examine the effect of co-encapsulation of islets with angiogenic protein on blood glucose control in diabetic animals. It is hoped that addition of tissue engineering to encapsulated islet transplantation will result in long-term survival of the islets and their ability to control blood glucose in type 1 diabetes without the necessity to use risky immunosuppressive drugs to prevent transplant rejection. PMID: 20683347 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using a Type 1 Collagen-Based System to Understand Cell-Scaffold Interactions and to Deliver Chimeric Collagen-Binding Growth Factors for Vascular Tissue Engineering. J Investig Med. 2010 Jul 30; Authors: Pang Y, Greisler HP Vascular tissue engineering should provide more biocompatible and functional conduits than synthetic vascular grafts. Understanding cell-scaffold interactions and developing an efficient delivery system for growth factors and other biomolecules to control the signaling between the cells and the scaffold are fundamental issues in a wide range of tissue engineering research fields. Type 1 collagen is a natural scaffold extensively used in vascular tissue engineering and is a widely used vehicle in biomolecule delivery. In this article, we will discuss type 1 collagen as a vascular tissue engineering scaffold, describe strategies for elucidating the interaction between cells and type 1 collagen scaffolds using various imaging techniques, and summarize our work on the development of a chimeric collagen-binding growth factor-based local delivery system. PMID: 20683346 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Regenerative Medicine: Basic Concepts, Current Status, and Future Applications. J Investig Med. 2010 Jul 30; Authors: Corona BT, Ward CL, Harrison BS, Christ GJ A recent report demonstrated that a laboratory-grown neobladder tissue could be successfully used for cystoplasty in young patients with myelomeningocele who were otherwise healthy. This remarkable achievement portends well for the application of tissue engineering/regenerative medicine technologies to the treatment of end-organ failure due to a variety of causes (ie, congenital, acquired, age or disease related). Nonetheless, the broader clinical use of these groundbreaking technologies awaits improved understanding of endogenous regenerative mechanisms, more detailed knowledge of the boundary conditions that define the current limits for tissue repair and replacement in vivo, and the parallel development of critical enabling technologies (ie, improved cell source, biomaterials, bioreactors). This brief report will review a number of the most salient features and recent developments in this rapidly advancing area of medical research and detail some of our own experience with bladder and skeletal muscle regeneration and replacement as examples that highlight both the promise and challenges facing regenerative medicine/tissue engineering. PMID: 20683344 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Strategies for Vascularization of Polymer Scaffolds. J Investig Med. 2010 Jul 30; Authors: Papavasiliou G, Cheng MH, Brey EM Biocompatible, degradable polymer scaffolds combined with cells or biological signals are being investigated as alternatives to traditional options for tissue reconstruction and transplantation. These approaches are already in clinical use as engineered tissues that enhance wound healing and skin regeneration. The continued enhancement of these material strategies is highly dependent on the ability to promote rapid and stable neovascularization (new blood vessel formation) within the scaffold. Whereas neovascularization therapies have shown some promise for the treatment of ischemic tissues, vascularization of polymer scaffolds in tissue engineering strategies provides a unique challenge owing to the volume and the complexity of the tissues targeted. In this article, we examine recent advances in research focused on promoting neovascularization in polymer scaffolds for tissue engineering applications. These approaches include the use of growth factors, cells, and novel surgical approaches to both enhance and control the nature of the vascular networks formed. The continued development of these approaches may lead to new tissue engineering strategies for the generation of skin and other tissues or organs. PMID: 20683343 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Analysis of power law models for the creep of nucleus pulposus tissue. Biorheology. 2010 Jan 1;47(2):143-51 Authors: Agosti CD, Bell KM, Plazek DJ, Larson J, Kang JD, Gilbertson LG, Smolinski P Tissue engineering approaches are now being investigated for altering the course of intervertebral disc degeneration (IDD). Because the disease changes the mechanical properties of the load bearing tissues of the disc, viscoelastic tissue behavior is a key measure for comparing the efficacy of treatments. To investigate the basic viscoelastic behavior of nucleus pulposus tissue, tissue from the rabbit disc was tested in torsional creep. Both the Andrade and Nutting creep models had a good fit to the data, however, the Andrade creep model gave a much better prediction of the longer term creep. This is the first application of Andrade creep to biological tissue and results indicate that this model may be particularly well suited for characterizing the viscoelastic behavior of very soft biological tissues. PMID: 20683157 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Special issue featuring articles from the 7th China-Korea Symposium on Biomaterials and Nano-Biotechnology. Biomed Mater. 2010 Aug;5(4):040201 Authors: Gu N, Yang HC Novel biomaterials are expected to provide us with more effective and safer ways to treat diseases that are threatening the lives of patients, or eroding their quality of life. As the walls between the fields of science break down, research into biomaterials, which requires multidisciplinary knowledge, is receiving unlimited opportunities in resources and for information sharing, leading to the development of innovative materials. Undoubtedly, nano-biotechnology is providing scientific breakthroughs in the field of biomaterials, and vice versa. In this vein, the articles featured in this special issue reflect the desire to share ideas, and the current state of research into biomaterials and nano-biotechnology in China and Korea, whilst providing a snapshot of the types of research being undertaken. The articles were peer reviewed and selected from the 7th China-Korea Symposium on Biomaterials and Nano-Biotechnology, held in Nanjing and Suzhou, People's Republic of China, on 19-23 October 2009. The symposium topics covered biopolymers, bioceramics, biometals, biocompatibility of biomaterials, tissue engineering and nano-biotechnology. Scientists from various universities and research institutes in both countries attended the symposium and shared their experiences and ideas for future cooperation on biomaterials and nano-biotechnology research. The symposium was supported financially by the National Natural Science Foundation of China (NSFC) and the Korea Science and Engineering Foundation (KOSEF). We would like to express our thanks to all the authors for contributing to this special issue, and to Professors F-Z Cui, I-S Lee, and M Spector, the Editors-in-Chief of Biomedical Materials, for arranging the publication of these articles in this issue. PMID: 20683146 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Investigation of the cytotoxicity mechanism of silver nanoparticles in vitro. Biomed Mater. 2010 Aug;5(4):044103 Authors: Wei L, Tang J, Zhang Z, Chen Y, Zhou G, Xi T Nowadays, more and more nanotechnology products and nanomaterials are being applied in our lives. Silver nanoparticles (SNPs) are used in infection prevention and treatment due to their antimicrobial activity. However, as a kind of nanomaterial, the toxicology of SNPs has not been completely studied. The mechanism of cytotoxicity of SNPs in vitro to mouse's fibroblast cells (L929) was investigated in this study. As a contrast, silver microparticles (SMPs) were also studied. Propidium iodide (PI) single staining and Annexin-V/PI staining were carried out to unveil the influence of SNPs and SMPs on the cells. A transmission electron microscope (TEM) was used to observe SNPs' distribution in the cells. The results of cell cycle analysis indicated that the cells treated with SNPs were arrested in the G2M phase. Meanwhile, SNPs lead to apoptosis of more cells compared to SMPs at the same dose as a result of apoptosis analysis. Analysis of the cells' ultrastructure showed that SNPs could be phagocytized into the cells while SMPs could not. The mechanism of cytotoxicity of SNPs in vitro to L929 cells may be that SNPs are phagocytized into the cells and they interact with mitochondria or other organelles, even nuclei, which results in cells' apoptosis or necrosis. PMID: 20683123 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Lab-Specific Gene Expression Signatures in Pluripotent Stem Cells. Cell Stem Cell. 2010 Aug 6;7(2):258-262 Authors: Newman AM, Cooper JB Pluripotent stem cells derived from both embryonic and reprogrammed somatic cells have significant potential for human regenerative medicine. Despite similarities in developmental potential, however, several groups have found fundamental differences between embryonic stem cell (ESC) and induced-pluripotent stem cell (iPSC) lines that may have important implications for iPSC-based medical therapies. Using an unsupervised clustering algorithm, we further studied the genetic homogeneity of iPSC and ESC lines by reanalyzing microarray gene expression data from seven different laboratories. Unexpectedly, this analysis revealed a strong correlation between gene expression signatures and specific laboratories in both ESC and iPSC lines. Nearly one-third of the genes with lab-specific expression signatures are also differentially expressed between ESCs and iPSCs. These data are consistent with the hypothesis that in vitro microenvironmental context differentially impacts the gene expression signatures of both iPSCs and ESCs. PMID: 20682451 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Transient Inactivation of Rb and ARF Yields Regenerative Cells from Postmitotic Mammalian Muscle. Cell Stem Cell. 2010 Aug 6;7(2):198-213 Authors: Pajcini KV, Corbel SY, Sage J, Pomerantz JH, Blau HM An outstanding biological question is why tissue regeneration in mammals is limited, whereas urodele amphibians and teleost fish regenerate major structures, largely by cell cycle reentry. Upon inactivation of Rb, proliferation of postmitotic urodele skeletal muscle is induced, whereas in mammalian muscle this mechanism does not exist. We postulated that a tumor suppressor present in mammals but absent in regenerative vertebrates, the Ink4a product ARF (alternative reading frame), is a regeneration suppressor. Concomitant inactivation of Arf and Rb led to mammalian muscle cell cycle reentry, loss of differentiation properties, and upregulation of cytokinetic machinery. Single postmitotic myocytes were isolated by laser micro-dissection-catapulting, and transient suppression of Arf and Rb yielded myoblast colonies that retained the ability to differentiate and fuse into myofibers upon transplantation in vivo. These results show that differentiation of mammalian cells is reversed by inactivation of Arf and Rb and support the hypothesis that Arf evolved at the expense of regeneration. PMID: 20682446 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Oxygen in Stem Cell Biology: A Critical Component of the Stem Cell Niche. Cell Stem Cell. 2010 Aug 6;7(2):150-161 Authors: Mohyeldin A, Garzón-Muvdi T, Quiñones-Hinojosa A The defining hallmark of stem cells is their ability to self-renew and maintain multipotency. This capacity depends on the balance of complex signals in their microenvironment. Low oxygen tensions (hypoxia) maintain undifferentiated states of embryonic, hematopoietic, mesenchymal, and neural stem cell phenotypes and also influence proliferation and cell-fate commitment. Recent evidence has identified a broader spectrum of stem cells influenced by hypoxia that includes cancer stem cells and induced pluripotent stem cells. These findings have important implications on our understanding of development, disease, and tissue-engineering practices and furthermore elucidate an added dimension of stem cell control within the niche. PMID: 20682444 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Differential DNA Damage Response in Stem and Progenitor Cells. Cell Stem Cell. 2010 Aug 6;7(2):145-147 Authors: Seita J, Rossi DJ, Weissman IL The long lifespan of tissue-specific stem cells suggests that they may respond differently to DNA damage than downstream cells. In this issue of Cell Stem Cell, two groups address this hypothesis by examining DNA damage responses in hematopoietic stem and progenitor cells (Milyavsky et al., 2010; Mohrin et al., 2010). PMID: 20682442 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There's No Place Like Home for a Neural Stem Cell. Cell Stem Cell. 2010 Aug 6;7(2):141-143 Authors: Siegenthaler JA, Pleasure SJ Neural precursor cells (NPCs) reside in the subventricular zone in association with blood vessels and ependymal cells. In this issue of Cell Stem Cell, Kokovay et al. (2010) show that SDF1 directs the association of NPCs with this niche and regulates their lineage progression in a stage-specific manner. PMID: 20682440 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hematopoietic stem cell lodgment in the adult bone marrow stem cell niche. Int J Lab Hematol. 2010 Aug 2; Authors: Lam BS, Adams GB Summary Treatment of malignant blood disorders, such as leukemia, that can provide a better chance of long-term remission involves myeloablation followed by transplantation of matched donor hematopoietic stem cells (HSCs). For successful engraftment and re-establishment of hematopoiesis to occur in the recipient, the transplanted HSCs must first migrate from the blood circulation to the bone marrow (BM), a process known as homing, then localize and anchor in suitable microenvironments within the BM, a process known as lodgment. After lodgment, the specific fate of the transplanted HSCs is determined through complex, bidirectional interactions with various stromal cell components in the niche. Ultimately, these interactions dictate the clinical outcome of the transplantation. Through the use of transgenic mouse models, considerable evidence has been accumulated in an attempt to unveil the possible underlying mechanisms that govern these processes. Here, we will emphasize the major factors that are involved in the regulation of lodgment of transplanted HSCs. Specifically, we will first introduce early observations on the spatial distribution of hematopoietic progenitors within the BM, then we will discuss the soluble factors, chemokines, cell-cell interactions, and cell-matrix interactions that have been studied and known to influence the site of HSC lodgment within the BM following transplantation. PMID: 20682000 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Hippocampus development and function: role of epigenetic factors and implications for cognitive disease. Clin Genet. 2010 Jul 6; Authors: Lagali P, Corcoran CP, Picketts DJ Lagali PS, Corcoran CP, Picketts DJ. Hippocampus development and function: role of epigenetic factors and implications for cognitive disease. The hippocampus is a primary region of the brain controlling the formation of memories and learned behaviours. The ability to learn or form a memory requires a neuron to translate a transient signal into gene expression changes that have a long-lasting effect on synapse activity and connectivity. Numerous studies over the past decade have detailed changes in epigenetic modifications under various learning paradigms to support a role for chromatin remodelling in these processes. Moreover, the identification of mutations in epigenetic regulators as the cause of mental retardation or intellectual disability (MR/ID) disorders further strengthens their importance to learning and memory. Animal models for many of these disorders are emerging and advancing our understanding of the molecular mechanisms linking epigenetic regulation and cognitive function. Here, we review how chromatin remodelling proteins implicated in MR/ID contribute to the development of the hippocampus and memory formation. PMID: 20681996 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Expression and secretion of interleukin-1beta, tumour necrosis factor-alpha and interleukin-10 by hypoxia- and serum-deprivation-stimulated mesenchymal stem cells. FEBS J. 2010 Jul 30; Authors: Li Z, Wei H, Deng L, Cong X, Chen X To understand the potential paracrine roles of interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and interleukin-10 (IL-10), the expression and secretion of these factors by rat bone marrow-derived mesenchymal cells stimulated by hypoxia (4% oxygen) and serum deprivation (hypoxia/SD) were investigated. We found that hypoxia/SD induced nuclear factor kappa Bp65-dependent IL-1beta and TNF-alpha transcription. Furthermore, hypoxia/SD stimulated the translation of pro-IL-1beta and its processing to mature IL-1beta, although the translation of TNF-alpha was unchanged. Unexpectedly, the release of IL-1beta and TNF-alpha from hypoxia/SD-stimulated mesenchymal cells was undetectable unless ATP or lipopolysaccharide was present. This result suggests that IL-1beta and TNF-alpha are not responsible for the paracrine effects of mesenchymal cells under ischaemic conditions. We also found that hypoxia/SD induced the transcription and secretion of IL-10, which were significantly enhanced by lipopolysaccharide and the proteasomal inhibitor MG132. Moreover, both the conditioned medium from hypoxia/SD-stimulated mesenchymal cells (MSC-CM) and IL-10 efficiently inhibited cardiac fibroblast proliferation and collagen expression in vitro, suggesting that mesenchymal cell-secreted IL-10 prevents cardiac fibrosis in a paracrine manner under ischaemic conditions. Taken together, these findings may improve understanding of the cellu-lar and molecular basis of the anti-inflammatory and paracrine effects of mesenchymal cells. PMID: 20681988 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Nanoparticles based on PLGA:poloxamer blends for the delivery of proangiogenic growth factors. Mol Pharm. 2010 Aug 3; Authors: d'Angelo I, Garcia-Fuentes M, Parajo Y, Welle A, Vantus T, Horvath A, Bökönyi G, Kéri G, Alonso MJ New blood vessel formation is a critical requirement for treating many vascular and ischemia related diseases, as well as for many tissue engineering applications. Angiogenesis and vasculogenesis, in fact, represent crucial processes for the functional regeneration of complex tissues through tissue engineering strategies. Several growth factors (GFs) and signalling molecules involved in blood vessels formation have been identified, but their application to the clinical setting is still strongly limited by their extremely short half-life in the body. To overcome these limitations, we have developed a new injectable controlled release device based on polymeric nanoparticles for the delivery of two natural proangiogenic GFs: Platelet Derived Growth Factor (PDGF-BB) and Fibroblast Growth Factor (FGF-2). The nanoparticle system was prepared by a modified solvent diffusion technique, encapsulating the GF both in presence and in the absence of two stabilizing agents: bovine serum albumin (BSA) and heparin sodium salt (Hp). The developed nanocarriers were characterized for morphology, size, encapsulation efficiency, release kinetics in vitro and GF activity in cell cultures. The results have indicated that the co-encapsulation of stabilizing agents can preserve the GF active structure and, in addiction, increase their encapsulation efficiency into nanoparticles. Through this optimization process, we were able to raise the encapsulation efficiency of FGF-2 to 63%, and that of PDGF-BB to 87%. These PLGA:poloxamer blend nanoparticles loaded with GFs were able to release PDGF-BB and FGF-2 in a sustained fashion for more than a month. This works also confirms other positive features of PLGA:poloxamer nanoparticles. Namely, they are able to maintain their stability in simulated biological medium, and they are also non-toxic to cell culture models. Incubation of nanoparticles loaded with FGF-2 or PDGF-BB with endothelial cell culture models have confirmed that GFs are released in a bioactive form. Altogether, these results underline the interest of PLGA:poloxamer nanoparticles for the controlled delivery of GFs and substantiate their potential for the treatment of ischemic diseases and for tissue engineering applications. PMID: 20681555 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Comparison of development of heterotopic ossification in injured US and UK Armed Services personnel with combat-related amputations: preliminary findings and hypotheses regarding causality. J Trauma. 2010 Jul;69 Suppl 1:S116-22 Authors: Brown KV, Dharm-Datta S, Potter BK, Etherington J, Mistlin A, Hsu JR, Clasper JC BACKGROUND: Recent reports have documented the rate of heterotopic ossification (HO) formation in the residual limbs of combat-related amputees from the US Armed Forces injured in Operations Iraqi and Enduring Freedom. Final amputation level within the zone of injury and blast as the mechanism of injury were identified as possible risk factors for the occurrence and grade of HO. There has been no previous description of HO in combat-related amputees from the UK service personnel. The purpose of this study was to examine potential differences in the prevalence of HO between UK and US Allied Forces, with particular attention to these risk factors, patient exposures, and any treatment differences between these two groups. METHODS: We reviewed the medical records and radiographs of 35 combat-related amputations from the UK and contrasted them with 213 previously reported amputations in US military personnel. We evaluated prevalence and severity of residual limb HO, Injury Severity Score (ISS), the mechanism and zone of injury, type and level of amputation, number of debridements, method of wound irrigation, presence of severe head injury and/or burns injury, use of topical negative pressure therapy and pulse lavage, number of days until wound closure, type of closure, and subsequent infections. All patients had a minimum of 2-month posthospital discharge radiographic follow-up. Comparisons were made using Fisher's exact, one-way analysis of variance, and chi2 analyses. RESULTS: There was no significant difference in either the overall prevalence of HO or the prevalence of moderate to severe HO in the two populations. Twenty of 35 (57.1%) limbs in the UK amputations developed HO compared with 134 of 213 (63%) in the US amputations (p > 0.05). The UK amputations had 12 cases (34.3%) of moderate to severe HO compared with 72 cases (33.8%) in the US amputations (p > 0.05). However, there was a significant difference in the number of UK amputations 0 of 20 (0%) versus the number of US amputations 25 of 134 (12%; p = 0.04), which required excision of symptomatic lesions. There was a significant association in the development of HO in UK personnel with the use of topical negative pressure treatment (p = 0.05) and increasing ISS scores (p = 0.04) and in the development of moderate to severe HO with increasing ISS (p = 0.006) and severe HI (p = 0.04). Unlike in the previous report, no significant association was found in UK personnel between any of the remaining hypothesized risk factors and either the presence or grade of HO. CONCLUSIONS: Although no difference was identified in the overall prevalence of HO, there are inconsistencies in the possible underlying causes of HO between the two cohorts. Further research is required in an ongoing effort to determine a causal relationship between treatment and subsequent HO formation. PMID: 20622605 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Infectious complications of combat-related mangled extremity injuries in the British military. J Trauma. 2010 Jul;69 Suppl 1:S109-15 Authors: Brown KV, Murray CK, Clasper JC BACKGROUND: During the wars in Iraq and Afghanistan, extremity injuries have predominated; however, no systematic review of field and stabilization care with subsequent infectious complications exists. This study evaluates the infectious complications and possible risk factors of British military casualties with mangled extremities, highlighting initial care and infections. METHODS: This is a retrospective cohort study of British military casualties in Iraq and Afghanistan between August 2003 and May 2008. Casualties with mangled extremities undergoing limb salvage were evaluated for management strategies at the time of injury through evacuation back to the United Kingdom and subsequent infections. RESULTS: There were 84 casualties with 85 extremities (20 infected and 65 uninfected). Infected extremities had more Gustilo Classification IIIb. There were no differences by Injury Severity Score, age, durations from injury to evacuation, or surgery, or arrival in England, use of clotting materials, or method of extremity stabilization between infected and uninfected extremity injuries. Tourniquet use in the field and fasciotomy were associated with infections. Antimicrobial coverage was associated with infections. Staphylococcus aureus were recovered later in casualties' clinical course in contrast to early recovery of Acinetobacter. On multivariate analysis, tourniquet in the field, antibiotics during evacuation and in the operating room, and fasciotomy were associated with infection as were certain bacteria, notably, Pseudomonas aeruginosa. CONCLUSION: Infections occurred in 24% of those with mangled extremities including 6% with osteomyelitis. Certain procedures, likely reflective of injury severity, were associated with infections along with certain bacteria, P. aeruginosa and possibly S. aureus. Continued clarification is required for antimicrobial coverage (penicillin-based regimens vs. additional anaerobic coverage) and certain surgical procedures to improve casualty care. PMID: 20622604 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gene expression profiling of primary human articular chondrocytes in high-density micromasses reveals patterns of recovery, maintenance, re- and dedifferentiation. Gene. 2010 Aug 15;462(1-2):8-17 Authors: Dehne T, Schenk R, Perka C, Morawietz L, Pruss A, Sittinger M, Kaps C, Ringe J The high-density micromass culture has been widely applied to study chondrocyte cell physiology and pathophysiological mechanisms. Since an integrated image has not been established so far, we analyzed the phenotypic alterations of human articular chondrocytes in this model on the broad molecular level. Freshly isolated chondrocytes were assembled as micromasses and maintained up to 6 weeks in medium containing human serum. Formation of cartilaginous extracellular matrix (ECM) was evaluated by histological and immunohistochemical staining. At 0, 3 and 6 weeks, chondrocyte micromasses were subjected to gene expression analysis using oligonucleotide microarrays and real-time RT-PCR. Micromasses developed a cartilaginous ECM rich in proteoglycans and type II collagen. On gene expression level, time-dependent expression patterns was observed. The induction of genes associated with cartilage-specific ECM (COL2A1 and COL11A1) and developmental signaling (GDF5, GDF10, ID1, ID4 and FGFR1-3) indicated redifferentiation within the first 3 weeks. The repression of genes related to stress response (HSPA1A and HSPA4), apoptotic events (HYOU1, NFKBIA and TRAF1), and degradation (MMP1, MMP10 and MMP12) suggested a recovery of chondrocytes. Constant expression of other chondrogenic (ACAN, FN1 and MGP) and hypertrophic markers (COL10A1, ALPL, PTHR1 and PTHR2) indicated a pattern of phenotypic maintenance. Simultaneously, the expression of chondrogenic growth (BMP6, TGFA, FGF1 and FGF2) and transcription factors (SOX9, EGR1, HES1 and TGIF1), and other cartilage ECM-related genes (COMP and PRG4) was consistently repressed and expression of collagens related to dedifferentiation (COL1A1 and COL3A1) was steadily induced indicating a progressing loss of cartilage phenotype. Likewise, a steady increase of genes associated with proliferation (GAS6, SERPINF1, VEGFB and VEGFC) and apoptosis (DRAM, DPAK1, HSPB, GPX1, NGFRAP1 and TIA1) was observed. Sequence and interplay of identified expression patterns suggest that chondrocyte micromass cultures maintain a differentiated phenotype up to 3 weeks in vitro and might be useful for studying chondrocyte biology, pathophysiology and differentiation. Cultivation longer than 6 weeks leads to progressing dedifferentiation of chondrocytes that should be considered on long-term evaluations. PMID: 20433912 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The biological activities of (1,3)-(1,6)-beta-d-glucan and porous electrospun PLGA membranes containing beta-glucan in human dermal fibroblasts and adipose tissue-derived stem cells. Biomed Mater. 2010 Aug;5(4):044109 Authors: Woo YI, Park BJ, Kim HL, Lee MH, Kim J, Yang YI, Kim JK, Tsubaki K, Han DW, Park JC In this study, we investigated the possible roles of (1,3)-(1,6)-beta-d-glucan (beta-glucan) and porous electrospun poly-lactide-co-glycolide (PLGA) membranes containing beta-glucan for skin wound healing, especially their effect on adult human dermal fibroblast (aHDF) and adipose tissue-derived stem cell (ADSC) activation, proliferation, migration, collagen gel contraction and biological safety tests of the prepared membrane. This study demonstrated that beta-glucan and porous PLGA membranes containing beta-glucan have enhanced the cellular responses, proliferation and migration, of aHDFs and ADSCs and the result of a collagen gel contraction assay also revealed that collagen gels contract strongly after 4 h post-gelation incubation with beta-glucan. Furthermore, we confirmed that porous PLGA membranes containing beta-glucan are biologically safe for wound healing study. These results indicate that the porous PLGA membranes containing beta-glucan interacted favorably with the membrane and the topical administration of beta-glucan was useful in promoting wound healing. Therefore, our study suggests that beta-glucan and porous PLGA membranes containing beta-glucan may be useful as a material for enhancing wound healing. PMID: 20683126 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Effects of adipose-derived stromal cells and of their extract on wound healing in a mouse model. J Korean Med Sci. 2010 May;25(5):746-51 Authors: Lim JS, Yoo G In this study, the authors investigated the effects of adipose-derived stromal cells (ADSCs) and of their extract on wound healing. After creating wound healing splint model on the backs of mice, ADSCs and their extract were applied. Wound healing rates were calculated at 3, 5, 7, 10, and 14 days after the wounding, and tissues were harvested at 7 and 14 days for histological analysis. Wound healing rates were significantly higher at 7, 10, and 14 days in the cell group than in the control, but in the cell extract group wound healing rates were significantly decreased (P<0.05). Histological scores and capillary densities in the cell group were significantly higher at 2 weeks (P<0.05). In the cell group, thick inflammatory cell infiltration and many capillaries were observed at 1 week, and thick epithelium and numerous large capillaries were observed at 2 weeks. The present study suggests that ADSCs accelerate wound healing as known, and the effects of ADSCs on wound healing may be due to replacing insufficient cells by differentiation of ADSCs in the wound and secreting growth factors by differentiated cells, and not due to the effect of factors within ADSCs. PMID: 20436712 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Gene expression, glycocalyx assay, and surface properties of human endothelial cells cultured on hydrogel matrix with sulfonic moiety: Effect of elasticity of hydrogel. J Biomed Mater Res A. 2010 Aug 2; Authors: Yang JJ, Chen YM, Kurokawa T, Gong JP, Onodera S, Yasuda K We measured the gene expression, glycocalyx content, and surface properties of human coronary artery endothelial cells (HCAECs) cultured on poly(sodium p-styrene sulfonate) (PNaSS) hydrogels with various levels of elasticity ranged in 3-300 kPa. We found that all HCAECs reached confluence on these hydrogels while retaining the similar expression of EC-specific markers to that on polystyrene (PS), a widely used scaffold in cell culture in vitro. Real-time polymerase chain reaction (PCR) and glycosaminoglycan (GAG) assay showed that the amount of EC-specific glycocalyx secreted by HCAECs cultured on PNaSS gels was higher than that cultured on PS, and it increased with an increase of gel elasticity. Furthermore, the HCAECs cultured on PNaSS gels showed excellent property against platelet adhesion and lower surface friction than that on PS. The platelet adhesion and surface friction of HCAECs cultured on PNaSS gels also depend on the elasticity of gels. The largest amount of EC-specific glycocalyx, excellent blood compatibility, and the lowest friction were observed when the elastic modulus of the gel was larger than 60 kPa. Overall, HCAECs cultured on these hydrogels have better properties than those cultured on PS scaffold, demonstrating the PNaSS gels can be used as potential tissue engineering material for blood vessels. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010. PMID: 20681030 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Large animal model of heart failure for assessment of stem cells. Methods Mol Biol. 2010;660:111-21 Authors: Rastogi S The field of stem cell biology and regenerative medicine is rapidly moving toward translation to clinical practice, and in doing so has become more dependent on animal donors and hosts for generating cellular reagents and assaying their potential therapeutic efficacy in models of human disease. Animal models of cardiovascular disease have proved critically important for the discovery of pathophysiological mechanisms and for the advancement of diagnosis and therapy. They offer a number of advantages; principally the availability of adequate healthy controls and the absence of confounding factors such as marked differences in age, concomitant pathologies, and pharmacological treatments. Over the past 30 years, investigators have developed numerous small and large animal models to study heart failure (HF). However, to translate discoveries from basic science into medical applications, research in large animal models becomes a necessary step. Intracoronary microembolizations-induced HF in dogs is an excellent large animal model of congestive HF for the assessment of pharmacological drugs, medical devices, and stem cells. PMID: 20680816 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Methods for human embryonic stem cells derived cardiomyocytes cultivation, genetic manipulation, and transplantation. Methods Mol Biol. 2010;660:85-95 Authors: Arbel G, Caspi O, Huber I, Gepstein A, Weiler-Sagie M, Gepstein L A decade has passed since the initial derivation of human embryonic stem cells (hESC). The ensuing years have witnessed a significant progress in the development of methodologies allowing cell cultivation, differentiation, genetic manipulation, and in vivo transplantation. Specifically, the potential to derive human cardiomyocytes from the hESC lines, which can be used for several basic and applied cardiovascular research areas including in the emerging field of cardiac regenerative medicine, attracted significant attention from the scientific community. This resulted in the development of protocols for the cultivation of hESC and their successful differentiation toward the cardiomyocyte lineage fate. In this chapter, we will describe in detail methods related to the cultivation, genetic manipulation, selection, and in vivo transplantation of hESC-derived cardiomyocytes. PMID: 20680814 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mesenchymal stem cell therapy for cardiac repair. Methods Mol Biol. 2010;660:65-84 Authors: Boyle AJ, McNiece IK, Hare JM Stem cell therapy for repair of damaged cardiac tissue is an attractive option to improve the health of the growing number of heart failure patients. Mesenchymal stem cells (MSCs) possess unique properties that may make them a better option for cardiac repair than other cell types. Unlike other adult stem cells, they appear to escape allorecognition by the immune system and they have immune-modulating properties, thus making it possible to consider them for use as an allogeneic cell therapy product. There is a large and growing body of preclinical and early clinical experience with MSC therapy that shows great promise in realizing the potential of stem cell therapy to effect repair of damaged cardiac tissue. This review discusses the mechanism of action of MSC therapy and summarizes the current literature in the field. PMID: 20680813 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Umbilical cord blood stem cells for myocardial repair and regeneration. Methods Mol Biol. 2010;660:29-52 Authors: Greco N, Laughlin MJ Cardiovascular disease remains a major cause of morbidity and mortality with substantial economic cost. There remains a need for therapeutic improvement for patients refractory to revascularization and those who redevelop occlusions following revascularization. Early evidence linked age-associated reductions in the levels of circulating marrow-derived hematopoietic stem cells (HSC), characterized by expression of early HSC markers CD133 and CD34, with the occurrence of cardiovascular events and associated death. Heart tissue has the endogenous ability to regenerate through the activation of resident cardiac stem cells or through recruitment of a stem cell population from other tissues, such as bone marrow. A number of clinical trials have utilized patient-derived autologous bone marrow-derived cells or whole BM uncultured mononuclear cells (MNC) infused or injected locally to augment angiogenesis. In most cases of treating animal models with human cells, the frequency of stem cell engraftment, the subsequent number of newly generated cardiomyocytes and vascular cells, and the augmentation of endogenous microvascular collateralization, either by deposition, transdifferentiation, and/or by cell fusion, appear to be too low to explain the significant cardiac improvement. Initially, it was hypothesized that cell therapy may work by cell replacement mechanisms, but recent evidence suggests alternatively that cell therapy works by providing trophic support to the injured tissues. An alternative hypothesis is that the transplanted stem cells release soluble cytokines and growth factors (i.e., paracrine factors) that function in a paracrine fashion, contributing to cardiac repair and regeneration by inducing cytoprotection and neovascularization. Another hypothesis which may also be operative is that cell therapy may mediate endogenous regeneration by the activation of resident cardiac stem cell. Well-established clinical trials have used cord blood for the treatment of hematological malignances (e.g., leukemia, lymphoma, myeloma) and nonmalignancies (e.g., in born errors of metabolism, sickle cells anemia, autoimmune diseases), but further advances in other areas of regenerative medicine (e.g., cardiac repair) will directly benefit with the use of cord blood. These clinical outcomes demonstrate that effector cells may be delivered by an allogeneic approach, where strict tissue matching may not be necessary and treatment may be achieved by making use of the trophic support capability of cell therapy and not by a cell replacement mechanism. PMID: 20680811 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Morphologic and transcriptomic comparison of adipose- and bone-marrow-derived porcine stem cells cultured in alginate hydrogels. Cell Tissue Res. 2010 Aug 3; Authors: Kim D, Monaco E, Maki A, de Lima AS, Kong HJ, Hurley WL, Wheeler MB Advances in bioengineering, material chemistry, and developmental biology have led to the design of three-dimensional (3D) culture systems that better resemble the surrounding structure and chemistry of the in situ niches of cells in tissues. This study was designed to characterize and compare porcine adipose-derived stem cells (ADSC) and bone-marrow-derived stem cells (BMSC) induced to differentiate toward osteogenic and adipogenic lineages in vitro by using a 3D alginate hydrogel. The morphology and gene expression of the two cell populations during differentiation were analyzed. Both ADSC and BMSC showed morphological evidence of osteogenic and adipogenic differentiation. Expression patterns of genes characteristic of the onset of osteogenic differentiation (ALP, COL1A1, SPARC, SPP1) were low at the beginning of culture and generally increased during the period of differentiation up to 28 days in culture. Expression of genes associated with adipogenic differentiation (ACSL1, ADFP, ADIPOQ, CD36, DBI, DGAT2, PPARG, SCD) was consistently increased in ADSC cultured in alginate hydrogel relative to the start of differentiation. However, adipogenic gene expression of BMSC cultured in alginate hydrogel was more limited when compared with that of ADSC. Evaluation of cell numbers (via the MTT staining assay) suggested a greater viability of BMSC under osteogenic conditions in alginate hydrogels than under adipogenic conditions, whereas ADSC had greater viability under adipogenic conditions than under osteogenic conditions. This study thus provides an important initial evaluation of ADSC and BMSC seeded and differentiated toward the osteogenic and adipogenic cell lineages in a 3D alginate hydrogel in vitro. PMID: 20680346 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Divergent Modulation of Adipose-Derived Stromal Cell Differentiation by TGF-beta1 Based on Species of Derivation. Plast Reconstr Surg. 2010 Aug;126(2):412-25 Authors: Levi B, James AW, Xu Y, Commons GW, Longaker MT BACKGROUND:: Adipose-derived stromal cells hold promise for skeletal tissue engineering. However, various studies have observed that adipose-derived stromal cells differ significantly in their biology depending on species of derivation. In the following study, the authors sought to determine the species-specific response of adipose-derived stromal cells to recombinant TGF-beta1 (rTGF-beta1). METHODS:: Adipose-derived stromal cells were derived from mouse and human sources. Recombinant TGF-beta1 was added to culture medium (2.5 to 10 ng/ml); proliferation and osteogenic and adipogenic differentiation were assessed by standardized parameters, including cell counting, alkaline phosphatase, alizarin red, oil red O staining, and quantitative real-time polymerase chain reaction. RESULTS:: Recombinant TGF-beta1 was found to significantly repress cellular proliferation in both mouse and human adipose-derived stromal cells (p < 0.01). Recombinant TGF-beta1 was found to significantly repress osteogenic differentiation in mouse adipose-derived stromal cells. In contrast, osteogenic differentiation of human adipose-derived stromal cells proceeded unimpeded in either the presence or the absence of rTGF-beta1. Interestingly, rTGF-beta1 induced expression of a number of osteogenic genes in human adipose-derived stromal cells, including BMP2 and BMP4. CONCLUSIONS:: The authors' results further detail an important facet in which mouse and human adipose-derived stromal cells differ. Mouse adipose-derived stromal cell osteogenesis is completely inhibited by rTGF-beta1, whereas human adipose-derived stromal cell osteogenesis progresses in the presence of rTGF-beta1. These data highlight the importance of species of derivation in basic adipose-derived stromal cell biology. Future studies will examine in more detail the species-specific differences among adipose-derived stromal cell populations. PMID: 20679827 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stem cell therapy for vascular regeneration: adult, embryonic, and induced pluripotent stem cells. Circulation. 2010 Aug 3;122(5):517-26 Authors: Leeper NJ, Hunter AL, Cooke JP PMID: 20679581 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | De novo generation of white adipocytes from the myeloid lineage via mesenchymal intermediates is age, adipose depot, and gender specific. Proc Natl Acad Sci U S A. 2010 Aug 2; Authors: Majka SM, Fox KE, Psilas JC, Helm KM, Childs CR, Acosta AS, Janssen RC, Friedman JE, Woessner BT, Shade TR, Varella-Garcia M, Klemm DJ It is generally assumed that white adipocytes arise from resident adipose tissue mesenchymal progenitor cells. We challenge this paradigm by defining a hematopoietic origin for both the de novo development of a subset of white adipocytes in adults and a previously uncharacterized adipose tissue resident mesenchymal progenitor population. Lineage and cytogenetic analysis revealed that bone marrow progenitor (BMP)-derived adipocytes and adipocyte progenitors arise from hematopoietic cells via the myeloid lineage in the absence of cell fusion. Global gene expression analysis indicated that the BMP-derived fat cells are bona fide adipocytes but differ from conventional white or brown adipocytes in decreased expression of genes involved in mitochondrial biogenesis and lipid oxidation, and increased inflammatory gene expression. The BMP-derived adipocytes accumulate with age, occur in higher numbers in visceral than in subcutaneous fat, and in female versus male mice. BMP-derived adipocytes may, therefore, account in part for adipose depot heterogeneity and detrimental changes in adipose metabolism and inflammation with aging and adiposity. PMID: 20679227 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Biophysical and chemical effects of fibrin on mesenchymal stromal cell gene expression. Acta Biomater. 2010 May 26; Authors: Huang NF, Chu J, Lee RJ, Li S Mesenchymal stromal cells (MSCs) are multipotent cells that have high expansion yields and fibrin is a native extracellular matrix (ECM) material widely used for cell delivery and surgery. MSCs and fibrin have tremendous potential for tissue engineering applications, but the effect of fibrin on MSCs is not well characterized. The purpose of this study was to analyze the role of fibrin in modulating MSC phenotype by gene expression analysis. The results demonstrate that fibrin up-regulated MSC gene expression of vasculogenic (FLK1, ACTA2, VECAD, SM22 and CNN1), myogenic (MYF5 and MYH13), neurogenic (TH and GFAP) and chondrogenic (COL2A1) markers after 5days incubation. These gene expression results were supported by induction of expression on the protein level for early lineage-specific markers such as ACTA2, FLK1 and MYF5. The ability of fibrin to modulate MSC gene expression was not affected by matrix pore size (80-110mum diameter) or Young's modulus (5-25kPa) and the differential expression of some phenotypic markers could be partially mimicked by other ECM proteins, such as fibronectin and collagen I. In some cases the inductive effect of fibrin on gene expression could be further augmented by treatment with growth factors such as nerve growth factor. However, the effect of fibrin appeared to be limited, as MSCs did not differentiate into fully mature cells based on immunofluorescence staining after 12days. This body of work provides a rational approach for studying the interactions of MSC with fibrin, which has important therapeutic implications for the delivery of stem cells. PMID: 20678460 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Comprehensive transcriptome analysis of mouse embryonic stem cell adipogenesis unravels new processes of adipocyte development. Genome Biol. 2010 Aug 3;11(8):R80 Authors: Billon N, Kolde R, Reimand J, Monteiro MC, Kull M, Peterson H, Tretyakov K, Adler P, Wdziekonski B, Vilo J, Dani C ABSTRACT: BACKGROUND: The current epidemic of obesity has caused a surge of interest in the study of adipose tissue formation. While major progress has been made in defining the molecular networks that control adipocyte terminal differentiation, the early steps of adipocyte development and the embryonic origin of this lineage remain largely unknown. RESULTS: Here we performed genome-wide analysis of gene expression during adipogenesis of mouse embryonic stem cells (ESCs). We then pursued comprehensive bioinformatic analyses, including de novo functional annotation and curation of the generated data within the context of biological pathways, to uncover novel biological functions associated with the early steps of adipocyte development. By combining in-depth gene regulation studies and in silico analysis of transcription factor binding site enrichment, we also provide insights into the transcriptional networks that might govern these early steps. CONCLUSIONS: This study supports several biological findings: firstly, adipocyte development in mouse ESCs is coupled to blood vessel morphogenesis and neural development, just as it is during mouse development. Secondly, the early steps of adipocyte formation involve major changes in signaling and transcriptional networks. A large proportion of the transcription factors that we uncovered in mouse ESCs are also expressed in the mouse embryonic mesenchyme and in adipose tissues, demonstrating the power of our approach to probe for genes associated with early developmental processes on a genome-wide scale. Finally, we reveal a plethora of novel candidate genes for adipocyte development and present a unique resource that can be further explored in functional assays. PMID: 20678241 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cell Therapy in Chronic Ischemic Heart Dysfunction With and Without Viability. Cardiovasc Hematol Disord Drug Targets. 2010 Jul 19; Authors: Sánchez PL, Sanz-Ruiz R, Fernández-Santos ME, Villa A, Gutiérrez E, Fernández L, Vázquez S, Lorenzo MJ, Fernández-Avilés F A growing number of clinical trials are evaluating the effects of stem cell therapy in patients with chronic ischemic heart dysfunction. As most of the clinical trials included a limited and different number of patients, various stem cell sources and several delivery approaches, results vary substantially between these studies. We analyse whether the assessment of myocardial viability may be important when evaluating effects of stem cell transplantation on parameters of left ventricular remodeling. Viability assessment could help to find the best type of stem cell and the best method of cell delivery to be used in chronic ischemic heart dysfunction. PMID: 20678064 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cells: Clinical Trials Results The End of the Beginning or the Beginning of the End? Cardiovasc Hematol Disord Drug Targets. 2010 Jul 19; Authors: Behfar A, Crespo-Diaz R, Nelson TJ, Terzic A, Gersh BJ With increasing focus on the advance towards curative solutions, it is hard not to be excited by the potential of stem cell-based therapy. Application of the stem cell paradigm to cardiovascular medicine has fostered the evolution of novel approaches aimed at reversing injury caused by ischemic and non-ischemic cardiomyopathy. The feasibility and safety of stem cell use has been established in over 3,000 patients with either recent myocardial infarction or chronic organ failure. Nonetheless, the efficacy of stem cell therapy continues to remain in question. Initial clinical trials have focused on evaluation of multiple adult stem cell phenotypes in their unaltered, naÃve state as a "first generation" resource for repair. Though significant strides in perfecting delivery of these biologics to the diseased heart have been achieved, the benefits with regard to myocardial functional recovery have been modest at best. One approach towards optimizing outcome may lie upon preemptive guidance of stem cells down the pathway of myocyte regeneration. As seen with pharmacotherapeutics in the last century, successful translation of "second generation" biotherapeutics in the 21(st) century will require close integration of a community of practice and science to ensure broad application of this emerging technology in the treatment of heart disease. PMID: 20678060 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Efficient derivation of embryonic stem cells from nuclear transfer and parthenogenetic embryos derived from cryopreserved oocytes. Cell Reprogram. 2010 Apr;12(2):203-11 Authors: Sung LY, Chang CC, Amano T, Lin CJ, Amano M, Treaster SB, Xu J, Chang WF, Nagy ZP, Yang X, Tian XC Abstract Deriving histocompatible embryonic stem (ES) cells by somatic cell nuclear transfer (SCNT) and parthenogenetic activation (PA) requires fresh oocytes, which prevents their applications in humans. Here, we evaluated the efficiency of deriving ES cells from mature metaphase II (MII) and immature metaphase I (MI) vitrified oocytes, by PA or SCNT, in a mouse model. We successfully generated ES cell lines from PA (MII and MI) and SCNT (MII and MI) blastocysts. These cell lines expressed genes and antigens characteristic of pluripotent ES cells and produced full-term pups upon tetraploid embryo complementation. This study established an animal model for efficient generation of patient-specific ES cell lines using cryopreserved oocytes. This is a major step forward in the application of therapeutic cloning and parthenogenetic technology in human regenerative medicine and will serve as an important alternative to the iPS cell technology in countries/regions where these technologies are permitted. PMID: 20677934 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The Comparison between Conditioned Media and Serum-Free Media in Human Embryonic Stem Cell Culture and Differentiation. Cell Reprogram. 2010 Apr;12(2):133-40 Authors: Hannoun Z, Fletcher J, Greenhough S, Medine C, Samuel K, Sharma R, Pryde A, Black JR, Ross JA, Wilmut I, Iredale JP, Hay DC Abstract Human embryonic stem cells (hESCs) offer an inexhaustible supply of human somatic cell types through their ability to self-renew while retaining pluripotency. As such, hESC-derived cell types are important for applications ranging from in vitro modeling to therapeutic use. However, for their full potential to be realized, both the growth of the undifferentiated cells and their derivatives must be performed in defined culture conditions. Many research groups maintain hESCs using mouse embryonic fibroblasts (MEF) and MEF conditioned medium (CM). The use of murine systems to support hESCs has been imperative in developing hESC technology; however, they suffer from some major limitations including lack of definition, xenobiotic nature, batch-to-batch variation, and labor-intensive production. Therefore, hESC culture definition is essential if hESC lines, and their derivatives are to be quality assured and manufactured to GMP. We have initiated the process of standardizing hESC tissue culture and have employed two serum-free media: mTeSR (MT) and Stem Pro (SP). hESCs were maintained in a pluripotent state, for over 30 passages using MT and SP. Additionally, we present evidence that hESCs maintained in MT and SP generate equivalent levels of human hepatic endoderm as observed with CM. This data suggests that MT and SP are effective replacements for MEF-CM in hESC culture, contributing to the standardization of hESC in vitro models and ultimately their application. PMID: 20677928 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Grafting of GABAergic precursors rescues deficits in hippocampal inhibition. Epilepsia. 2010 Jul;51 Suppl 3:66-70 Authors: Calcagnotto ME, Zipancic I, Piquer-Gil M, Mello LE, Alvarez-Dolado M gamma-Aminobutyric acid (GABA) has an important role in the mechanism of epilepsy. Cell grafts from different sources have been performed to modulate local circuits or increase GABAergic inhibition in animal models of epilepsy. Among the different transplanted cell types, the medial ganglionic eminence (MGE)-derived cells present the best properties to be used in cell-based therapy. In this work we review previous experiences with these cells. In addition, we present new evidence showing their ability to modulate the levels of inhibition in the host brain of mice with alterations in the GABAergic system, caused by the specific ablation of hippocampal interneurons. Grafted GFP(+) MGE-derived cells occupied the area of ablation and differentiated into mature NK-1-, SOM-, PV-, CR-, and NPY-expressing interneurons. Inhibitory postsynaptic current (IPSC) frequency and amplitude on CA1 pyramidal cells of the ablated hippocampus significantly increased after transplantation, reaching levels similar to controls. Our data strongly suggest the suitability of MGE-derived cells for the treatment of neurologic conditions for which an increase or modulation of synaptic inhibition is required. PMID: 20618404 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Proceedings of the American Association of Oral and Maxillofacial Surgeons 2009 Research Summit. J Oral Maxillofac Surg. 2010 Aug;68(8):1711-22 Authors: Le AD, Lee JS, Dodson TB, Kademani D, Feinberg SE, Shetty V, Wohlford ME, Zuniga JR, Cunningham LL PMID: 20542614 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Intervertebral disc regeneration: influence of growth factors on differentiation of human mesenchymal stem cells (hMSC). Int J Artif Organs. 2010 Apr;33(4):244-52 Authors: Ehlicke F, Freimark D, Heil B, Dorresteijn A, Czermak P INTRODUCTION: One common cause of disability in modern society is low back pain. The main reason for this pain is the degeneration of the intervertebral disc (IVD), particularly of the nucleus pulposus (NP). For the early degeneration stage, a cell-based therapy could constitute a minimally invasive method of treatment. Therefore, adequate cells are needed. As the usage of NP cells is limited because of their insufficient amount or vitality, a promising alternative is the application of human mesenchymal stem cells (hMSCs) OBJECTIVE: To investigate the potential of various growth factors to induce the differentiation of hMSCs into NP cells and thereby to obtain an alternative cell source for the treatment of IVD degeneration. METHODS: hMSC-TERT were cultivated three-dimensionally in a hydrogel for 21 days to form NP cells. Cell survival and proliferation were determined using SybrGreen/propidium iodide double staining and the WST-test. To investigate the ability of several growth factors to differentiate hMSCs into NP cells, fluorescence immunostaining of NP-specific marker proteins (e.g., chondroadherin (CHAD) and the recently discovered cytokeratin 19) were performed. RESULTS: Following the procedure described above, cells are able to maintain their viability and proliferation capacity throughout the cultivation time. By using a previously established immunofluorescence protocol, we were able to indicate the ability of three different growth factors for differentiating hMSCs into NP-like cells. CONCLUSION: The expression of several marker proteins in all differentiation experiments indicates the ability of IGF-1, FGF-2 and PDGF-BB to differentiate hMSCs into NP-like cells apart from the usually applied TGF-beta3. Furthermore, our findings preclude the application of Cytokeratin 19 as a specific marker protein for NP cells. Further experiments have to be done to find real specific NP marker proteins to indisputably verify the differentiation of hMSCs into NP cells. If so, application of these three growth factors would possibly be an option to obtain sufficient NP cells for minimally invasive IVD regeneration. PMID: 20458694 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Combined impedance spectroscopy and Fourier domain optical coherence tomography to monitor cells in three-dimensional structures. Int J Artif Organs. 2010 Apr;33(4):238-43 Authors: Bagnaninchi PO OBJECTIVES: To assess non-invasively and in real time the three- dimensional organization of cells within porous matrices by combining Fourier Domain Optical Coherence Tomography (FDOCT) and Impedance Spectroscopy (IS). MATERIALS AND METHODS: Broadband interferences resulting from the recombination of in-depth light scattering events within the sample and light from a reference arm are measured as a modulation of the spectrum generated by a superluminescent laser diode (lambdao = 930nm, FWHM 90nm). Fourier transform allows in-depth localization of the scatterers, and the 3D microstructure of the sample is reconstructed by raster scanning. Simultaneously impedance spectroscopy is performed with a dielectric probe connected to an impedance analyzer to gather additional cellular information, and synchronized with FDOCT measurements. RESULTS: A combined IS-FDOCT system allowing an axial resolution of 5 micrometer in tissues and impedance measurements over the range 20MHz-1GHz has been developed. Alginate matrices have been characterized in terms of microstructure and impedance. Matrices seeded with adipose-derived stem cells have been monitored without the use of labeling agent. CONCLUSIONS: We have developed a multimodality system that will be instrumental to non-invasively monitor changes in total cell volume fraction and infer cell-specific dielectric properties in 3D structure. PMID: 20458693 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of cartilage specific matrix synthesis of human articular chondrocytes after extended propagation on microcarriers by image analysis. Int J Artif Organs. 2010 Apr;33(4):204-18 Authors: Goepfert C, Lutz V, Lünse S, Kittel S, Wiegandt K, Kammal M, Püschel K, Pörtner R BACKGROUND: Cell-based technologies for the repair of cartilage defects usually rely on the expansion of low numbers of chondrocytes isolated from biopsies of healthy cartilage. Proliferating chondrocytes are known to undergo dedifferentiation characterized by downregulation of collagen type II and proteoglycan production, and by upregulation of collagen type I synthesis. Re-expression of cartilage specific matrix components by expanded chondrocytes is therefore critical for successful cartilage repair. METHODS: Human articular chondrocytes were expanded on microcarriers Cytodex 3. The growth area was increased by adding empty microcarriers. Added microcarriers were colonized by bead-to-bead transfer of the cells. The chondrocytes were harvested from the microcarriers and characterized by their ability to synthesize collagen type II when cultivated in alginate beads using chondrogenic growth factors. A semi-automatic image analysis technique was developed to determine the fractions of collagen type II and type I positive cells. RESULTS: The expansion of human articular chondrocytes on microcarriers yielded high cell numbers and propagation rates compared to chondrocytes expanded in flask culture for one passage. The proportion of collagen type II positive cells compared to collagen type I synthesizing cells was increased compared to chondrocytes expanded using conventional methods. The matrix synthesis upon treatment with chondrogenic factors IGF-I and BMP-7 was enhanced whereas TGF-ss had an inhibitory effect on microcarrier expanded chondrocytes. CONCLUSIONS: Expanding human articular chondrocytes on microcarriers omitting subcultivation steps leads to superior ratios of collagen type II to type I forming cells compared to the expansion in conventional monolayer culture. PMID: 20458690 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Osteoclastic bioresorption of biomaterials: two- and three-dimensional imaging and quantification. Int J Artif Organs. 2010 Apr;33(4):198-203 Authors: Winkler T, Hoenig E, Huber G, Janssen R, Fritsch D, Gildenhaar R, Berger G, Morlock MM, Schilling AF PURPOSE: Bioresorbable materials have been developed in the hope that the body will replace them with newly formed tissue. The first step of this remodeling process in bone is the bioresorption of the material by osteoclasts. The aim of this study was to analyze osteoclastic resorption of biomaterials in vitro using the commonly used two-dimensional methods of light-microscopy (LM) and scanning electron microscopy (SEM) in comparison with infinite focus microscopy (IFM), a recently developed imaging method allowing for three-dimensional surface analysis. METHODS: Human hematopoietic stem cells were cultivated in the presence of the cytokines M-CSF and RANK-L for 4 weeks directly on dentin and a calcium phosphate cement. Osteoclast development was surveyed with standard techniques. After removal of the cells, resorption was characterized and quantified by LM, SEM and IFM. RESULTS: Osteoclast cultures on the biomaterials presented the typical osteoclast-specific markers. On dentin samples LM, SEM as well as IFM allowed for discrimination of resorption. Quantification of the resorbed area showed a linear correlation between the results (LM vs. SEM: r=0.996, p=0.004; SEM vs. IFM: r=0.989, p=0.011; IFM vs. LM: r=0.995). It was not possible to demarcate resorption pits on GB14 using LM or SEM. With IFM, resorption on GB14 could be visualized and quantified two- and three-dimensionally. CONCLUSIONS: In this paper we introduce IFM as a technology for three-dimensional visualization and quantification of resorption of biomaterials. Better understanding of the bioresorption of biomaterials may help in the design of better materials and might therefore constitute an important step on the avenue to the development of artificial bone. PMID: 20458689 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | You can look (but you better not touch)* - bioengineering and imaging. Int J Artif Organs. 2010 Apr;33(4):191-2 Authors: Czermak P, Catapano G PMID: 20458687 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mechanical dissociation of swine liver to produce organoid units for tissue engineering and in vitro disease modeling. Artif Organs. 2010 Jan;34(1):75-8 Authors: Irani K, Pomerantseva I, Hart AR, Sundback CA, Neville CM, Vacanti JP The complex intricate architecture of the liver is crucial to hepatic function. Standard protocols used for enzymatic digestion to isolate hepatocytes destroy tissue structure and result in significant loss of synthetic, metabolic, and detoxification processes. We describe a process using mechanical dissociation to generate hepatic organoids with preserved intrinsic tissue architecture from swine liver. Oxygen-supplemented perfusion culture better preserved organoid viability, morphology, serum protein synthesis, and urea production, compared with standard and oxygen-supplemented static culture. Hepatic organoids offer an alternative source for hepatic assist devices, engineered liver, disease modeling, and xenobiotic testing. PMID: 20432518 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Evaluation of the hemodynamics of a tissue-engineered hybrid graft. Artif Organs. 2010 Jan;34(1):E17-21 Authors: Son KH, Fang YH, Choi YJ, Noh I, Won JK, Park Y, Lee SH, Sun K, Son HS We evaluated the hemodynamics of tissue-engineered hybrid graft in vivo. The hybrid expanded polytetrafluoroethylene (ePTFE) scaffold was fabricated by coating the ePTFE graft with poly (lactide-co-glycolide) (PLGA) solution. This scaffold was turned into an engineered hybrid graft by culturing smooth muscle cells on its surface. Both the ePTFE (n = 6) and the engineered hybrid grafts (n = 8) were implanted in the carotid arteries of mongrel dogs. The length of intima in the engineered hybrid graft was greater than the ePTFE. The neoarterial thickness in the engineered hybrid group was greater, and the foreign body reaction was more severe. We compared the hemodynamics (diameter, flow rate, pulsatile index, mean velocity, shear stress, resistance index, and systolic/diastolic ratio) of the native arteries in the distal anastmosis. The shear rate in the engineered hybrid group was higher immediately after implantation, and the resistance index was lower, but there was no significant difference after 4 weeks. The engineered grafts demonstrated similar hemodynamics with the ePTFE grafts after 4 weeks implantation. PMID: 20420595 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use of stem cells in the biological repair of articular cartilage. Expert Opin Biol Ther. 2010 Jan;10(1):43-55 Authors: Nelson L, Fairclough J, Archer CW IMPORTANCE OF THE FIELD: Articular cartilage is avascular, aneural, and renowned for its poor capacity to repair after damage. For decades scientists and clinicians have deliberated over the potential to repair or regenerate articular cartilage and to date many techniques have been used in an attempt to create the best possible repair tissue. AREAS COVERED IN THIS REVIEW: This review article summarises surgical interventions that have been developed since the late 1940's; covering conservative strategies, invasive techniques and touching upon latest advancements involving stem cells and tissue engineering. WHAT WILL THE READER GAIN: The reader will gain a sound understanding into the history and background of strategies that have developed in attempts to reverse clinical symptoms of damaged or diseased articular cartilage. The article provides an insight into the plethora of potential repair mechanisms, and reviews future developments involving stem cells and biomaterials. TAKE HOME MESSAGE: Although work is still in its infancy, the use of stem cells in the biological repair of articular cartilage provides a promising outlook onto future developments; advancing from strategies and techniques that are already in use. PMID: 20420516 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Osteogenic induction of adipose-derived stromal cells: not a requirement for bone formation in vivo. Artif Organs. 2010 Jan;34(1):46-54 Authors: Li X, Yao J, Wu L, Jing W, Tang W, Lin Y, Tian W, Liu L Osteogenic induction was regarded as an indispensable step for adipose-derived stromal cells (ADSCs) to have osteogenic ability. Non-induced ADSCs can also produce bone in vivo and heal skeletal defects. The present study aimed to compare the bone-forming ability of osteogenically induced ADSCs and non-induced ADSCs in vivo. Tissue-engineered constructs were prepared from osteogenically induced or non-induced ADSCs and porous hydroxyapatite/beta-tricalcium phosphate scaffolds. A scaffold without cells and an empty defect group were used as control. All were implanted in rat critical calvarial defects. After implantation for 6 and 12 weeks, bone formation was analyzed using histomorphometry and microcomputed tomography; there were no significant differences in the formation of new bone between osteogenically induced ADSCs and non-induced ADSCs (P > 0.05). In conclusion, osteogenic induction of ADSCs is not an indispensable step for bone formation in vivo. Non-induced ADSCs can also be used as seeding cells to construct bone tissue. PMID: 19821812 [PubMed - indexed for MEDLINE] | | | | | | | | | | |  |
No comments:
Post a Comment