|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Deformability-based cell classification and enrichment using inertial microfluidics. Lab Chip. 2011 Jan 27; Authors: Hur SC, Henderson-Maclennan NK, McCabe ER, Di Carlo D The ability to detect and isolate rare target cells from heterogeneous samples is in high demand in cell biology research, immunology, tissue engineering and medicine. Techniques allowing label-free cell enrichment or detection are especially important to reduce the complexity and costs towards clinical applications. Single-cell deformability has recently been recognized as a unique label-free biomarker for cell phenotype with implications for assessment of cancer invasiveness. Using a unique combination of fluid dynamic effects in a microfluidic system, we demonstrate high-throughput continuous label-free cell classification and enrichment based on cell size and deformability. The system takes advantage of a balance between deformability-induced and inertial lift forces as cells travel in a microchannel flow. Particles and droplets with varied elasticity and viscosity were found to have separate lateral dynamic equilibrium positions due to this balance of forces. We applied this system to successfully classify various cell types using cell size and deformability as distinguishing markers. Furthermore, using differences in dynamic equilibrium positions, we adapted the system to conduct passive, label-free and continuous cell enrichment based on these markers, enabling off-chip sample collection without significant gene expression changes. The presented method has practical potential for high-throughput deformability measurements and cost-effective cell separation to obtain viable target cells of interest in cancer research, immunology, and regenerative medicine. PMID: 21271000 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Stem cells and cell therapy: on the eve of scientific approach]. Tsitologiia. 2010;52(11):918-20 Authors: Cell therapy and the stem cells (SC) have become a popular topic during last time. The theme is cluttered with numerous publications of questionable reliability. Not all methods applied in praxis are founded on evidence-based research. In the abundant literature, there is a gap between the supposed SC's healing properties associated with their capability to migrate to and engraft in injured tissue, and lack of clear morphological evidence thereof. Accordingly, there is a gap between advertizing and the better part of professional literature: the former speaks about rejuvenation of tissues, and the latter explains sometimes questionable therapeutic effects by paracrine or immunomodulating mechanisms, secretion of cytokines and growth factors. However, a SC is an undifferentiated cell, and a specific and efficient paracrine function can hardly be awaited from it as compared to others, more differentiated cells. It should be noted in conclusion that the main problem with the SC and cell therapy is commercial influence. Probably, experience of some foreign countries should be studied, where moves have been made to stop the use of unproven treatments, including some stem cell therapy. PMID: 21268850 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Wnt11 promotes cardiomyocyte development by caspase-mediated suppression of canonical Wnt signals. Mol Cell Biol. 2011 Jan;31(1):163-78 Authors: Abdul-Ghani M, Dufort D, Stiles R, De Repentigny Y, Kothary R, Megeney LA Specification and early patterning of the vertebrate heart are dependent on both canonical and noncanonical wingless (Wnt) signal pathways. However, the impact of each Wnt pathway on the later stages of myocardial development and differentiation remains controversial. Here, we report that the components of each Wnt signal conduit are expressed in the developing and postnatal heart, yet canonical/β-catenin activity is restricted to nonmyocardial regions. Subsequently, we observed that noncanonical Wnt (Wnt11) enhanced myocyte differentiation while preventing stabilization of the β-catenin protein, suggesting active repression of canonical Wnt signals. Wnt11 stimulation was synonymous with activation of a caspase 3 signal cascade, while inhibition of caspase activity led to accumulation of β-catenin and a dramatic reduction in myocyte differentiation. Taken together, these results suggest that noncanonical Wnt signals promote myocyte maturation through caspase-mediated inhibition of β-catenin activity. PMID: 21041481 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Distinct physiological and behavioural functions for parental alleles of imprinted Grb10. Nature. 2011 Jan 27;469(7331):534-538 Authors: Garfield AS, Cowley M, Smith FM, Moorwood K, Stewart-Cox JE, Gilroy K, Baker S, Xia J, Dalley JW, Hurst LD, Wilkinson LS, Isles AR, Ward A Imprinted genes, defined by their preferential expression of a single parental allele, represent a subset of the mammalian genome and often have key roles in embryonic development, but also postnatal functions including energy homeostasis and behaviour. When the two parental alleles are unequally represented within a social group (when there is sex bias in dispersal and/or variance in reproductive success), imprinted genes may evolve to modulate social behaviour, although so far no such instance is known. Predominantly expressed from the maternal allele during embryogenesis, Grb10 encodes an intracellular adaptor protein that can interact with several receptor tyrosine kinases and downstream signalling molecules. Here we demonstrate that within the brain Grb10 is expressed from the paternal allele from fetal life into adulthood and that ablation of this expression engenders increased social dominance specifically among other aspects of social behaviour, a finding supported by the observed increase in allogrooming by paternal Grb10-deficient animals. Grb10 is, therefore, the first example of an imprinted gene that regulates social behaviour. It is also currently alone in exhibiting imprinted expression from each of the parental alleles in a tissue-specific manner, as loss of the peripherally expressed maternal allele leads to significant fetal and placental overgrowth. Thus Grb10 is, so far, a unique imprinted gene, able to influence distinct physiological processes, fetal growth and adult behaviour, owing to actions of the two parental alleles in different tissues. PMID: 21270893 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Dental pulp stem cells in regenerative dentistry. Odontology. 2011 Jan;99(1):1-7 Authors: Casagrande L, Cordeiro MM, Nör SA, Nör JE Stem cells constitute the source of differentiated cells for the generation of tissues during development, and for regeneration of tissues that are diseased or injured postnatally. In recent years, stem cell research has grown exponentially owing to the recognition that stem cell-based therapies have the potential to improve the life of patients with conditions that span from Alzheimer's disease to cardiac ischemia to bone or tooth loss. Growing evidence demonstrates that stem cells are primarily found in niches and that certain tissues contain more stem cells than others. Among these tissues, the dental pulp is considered a rich source of mesenchymal stem cells that are suitable for tissue engineering applications. It is known that dental pulp stem cells have the potential to differentiate into several cell types, including odontoblasts, neural progenitors, osteoblasts, chondrocytes, and adipocytes. The dental pulp stem cells are highly proliferative. This characteristic facilitates ex vivo expansion and enhances the translational potential of these cells. Notably, the dental pulp is arguably the most accessible source of postnatal stem cells. Collectively, the multipotency, high proliferation rates, and accessibility make the dental pulp an attractive source of mesenchymal stem cells for tissue regeneration. This review discusses fundamental concepts of stem cell biology and tissue engineering within the context of regenerative dentistry. PMID: 21271319 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Cell Therapy for Central Nervous System Disorders.] No Shinkei Geka. 2011 Jan;39(1):5-23 Authors: Kanemura Y PMID: 21270475 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Chronic fetal hypoxia produces selective brain injury associated with altered nitric oxide synthases. Am J Obstet Gynecol. 2011 Jan 26; Authors: Dong Y, Yu Z, Sun Y, Zhou H, Stites J, Newell K, Weiner CP OBJECTIVE:: The purpose of this study was to investigate the impact of chronic hypoxia on the nitric oxide synthase isoenzymes in specific brain structures. STUDY DESIGN:: Time-mated pregnant guinea pigs were exposed to 10.5% molecular oxygen for 14 days (animals with chronic fetal hypoxia; HPX) or room air (control animals; NMX); L-N6-(1-iminoethyl)-lysine (L-NIL; an inducible nitric oxide synthase inhibitor, 1 mg/kg/d) was administered to HPX group for 14 days (L-NIL + HPX). Fetal brains were harvested at term. Multilabeled immunofluorescence was used to generate a brain injury map. Laser capture microdissection and quantitative polymerase chain reaction were applied; cell injury markers, apoptosis activation, neuron loss, total nitric oxide, and the levels of individual nitric oxide synthase isoenzymes were quantified. RESULTS:: Chronic hypoxia causes selective fetal brain injury rather than global. Injury is associated with differentially affected nitric oxide synthases in both neurons and glial cells, with inducible macrophage-type nitric oxide synthase up-regulated at all injury sites. L-NIL attenuated the injury, despite continued hypoxia. CONCLUSION:: These studies demonstrate that chronic hypoxia selectively injures the fetal brain in part by the differential regulation of nitric oxide synthase isoenzymes in an anatomic- and cell-specific manner. PMID: 21272843 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Identification of adult nephron progenitors capable of kidney regeneration in zebrafish. Nature. 2011 Jan 26; Authors: Diep CQ, Ma D, Deo RC, Holm TM, Naylor RW, Arora N, Wingert RA, Bollig F, Djordjevic G, Lichman B, Zhu H, Ikenaga T, Ono F, Englert C, Cowan CA, Hukriede NA, Handin RI, Davidson AJ Loss of kidney function underlies many renal diseases. Mammals can partly repair their nephrons (the functional units of the kidney), but cannot form new ones. By contrast, fish add nephrons throughout their lifespan and regenerate nephrons de novo after injury, providing a model for understanding how mammalian renal regeneration may be therapeutically activated. Here we trace the source of new nephrons in the adult zebrafish to small cellular aggregates containing nephron progenitors. Transplantation of single aggregates comprising 10-30 cells is sufficient to engraft adults and generate multiple nephrons. Serial transplantation experiments to test self-renewal revealed that nephron progenitors are long-lived and possess significant replicative potential, consistent with stem-cell activity. Transplantation of mixed nephron progenitors tagged with either green or red fluorescent proteins yielded some mosaic nephrons, indicating that multiple nephron progenitors contribute to a single nephron. Consistent with this, live imaging of nephron formation in transparent larvae showed that nephrogenic aggregates form by the coalescence of multiple cells and then differentiate into nephrons. Taken together, these data demonstrate that the zebrafish kidney probably contains self-renewing nephron stem/progenitor cells. The identification of these cells paves the way to isolating or engineering the equivalent cells in mammals and developing novel renal regenerative therapies. PMID: 21270795 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Fetal derived embryonic-like stem cells improve healing in a large animal flexor tendonitis model. Stem Cell Res Ther. 2011 Jan 27;2(1):4 Authors: Watts AE, Yeager AE, Kopyov OV, Nixon AJ ABSTRACT: INTRODUCTION: Tendon injury is a common problem in athletes, with poor tissue regeneration and a high rate of re-injury. Stem cell therapy is an attractive treatment modality as it may induce tissue regeneration rather than tissue repair. Currently, there are no reports on the use of pluripotent cells in a large animal tendon model in vivo. We report the use of intra-lesional injection of male, fetal derived embryonic-like stem cells (fdESC) that express Oct-4, Nanog, SSEA4, Tra 1-60, Tra 1-81 and telomerase. METHODS: Tendon injury was induced using a collagenase gel-physical defect model in the mid-metacarpal region of the superficial digital flexor tendon (SDFT) of 8 female adult Thoroughbred or Thoroughbred cross horses. Tendon lesions were treated 1 week later with intra-lesional injection of male derived fdESCs in media or media alone. Therapy was blinded and randomized. Serial ultrasound examinations were performed and final analysis at 8 weeks included magnetic resonance imaging (MRI), biochemical assays (total DNA, gylcosaminoglycan, collagen), gene expression (TNC, TNMD, SCX, COL1A1, COL3A1, COMP, DCN, MMP1, MMP3, MMP13, 18S) and histology. Differences between groups were assessed with Wilcoxon's rank sum test. RESULTS: Cell survival was demonstrated via the presence of the SRY gene in fdESC treated, but not control treated, female SDFT at the end of the trial. There were no differences in tendon matrix specific gene expression or total proteoglycan, collagen or DNA of tendon lesions between groups. Tissue architecture, tendon size, tendon lesion size, and tendon linear fiber pattern were significantly improved on histologic sections and ultrasound in the fdESC treated tendons. CONCLUSIONS: Such profound structural effects lend further support to the notion that pluripotent stem cells can effect musculoskeletal regeneration, rather than repair, even without in vitro lineage specific differentiation. Further investigation into the safety of pluripotent cellular therapy as well as the mechanisms by which repair was improved seem warranted. PMID: 21272343 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The relationship between collagen scaffold cross-linking agents and neutrophils in the foreign body reaction. Biomaterials. 2010 Dec;31(35):9192-201 Authors: Ye Q, Harmsen MC, van Luyn MJ, Bank RA In order to get more insight into the role of neutrophils on the micro-environment and consequently on macrophages in the foreign body reaction in mice, we investigated the fate of the two differently cross-linked dermal sheep collagen disks (glutaraldehyde = GDSC, hexamethylenediisocyanate = HDSC) in mice implanted in one anatomical location, namely subcutaneously. In GDSC massive infiltration of neutrophils is seen at day 2 and day 21, whereas in HDSC only minor infiltration is seen at day 2. The presence of neutrophils coincided with high levels of IFN-γ, a cytokine that activates macrophages. Major differences were seen in degradation rate of the two disks: GDSC was almost completely degraded after 28 days, whereas HDSC remained intact. Degradation of GDSC occurred through collagenolytic activity and phagocytosis by macrophages. Phagocytosis was observed at day 2 and day 21. IL-13 was only observed in HDSC, and this resulted in the presence of giant cells in HDSC. These giant cells produced IL-10, that promoted TIMP-1 expression and that inhibits collagenolytic and phagocytic activity. We conclude that the function of macrophages in mice is largely influenced by differences in micro-environment induced by GDSC and HDSC and that the presence/absence of neutrophils play a major role in the shaping of this micro-environment. PMID: 20828809 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Spatial control of gene expression within a scaffold by localized inducer release. Biomaterials. 2011 Jan 24; Authors: Baraniak PR, Nelson DM, Leeson CE, Katakam AK, Friz JL, Cress DE, Hong Y, Guan J, Wagner WR Gene expression can be controlled in genetically modified cells by employing an inducer/promoter system where presence of the inducer molecule regulates the timing and level of gene expression. By applying the principles of controlled release, it should be possible to control gene expression on a biomaterial surface by the presence or absence of inducer release from the underlying material matrix, thus avoiding alternative techniques that rely upon uptake of relatively labile DNA from material surfaces. To evaluate this concept, a modified ecdysone-responsive gene expression system was transfected into B16 murine cells and the ability of an inducer ligand, which was released from elastomeric poly(ester urethane) urea (PEUU), to initiate gene expression was studied. The synthetic inducer ligand was first loaded into PEUU to demonstrate extended release of the bioactive molecule at various loading densities over a one year period in vitro. Patterning films of PEUU variably-loaded with inducer resulted in spatially controlled cell expression of the gene product (green fluorescent protein, GFP). In porous scaffolds made from PEUU by salt leaching, where the central region was exclusively loaded with inducer, cells expressed GFP predominately in the loaded central regions whereas expression was minimal in outer regions where ligand was omitted. This scaffold system may ultimately provide a means to precisely control progenitor cell commitment in a spatially-defined manner in vivo for soft tissue repair and regeneration. PMID: 21269687 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Use of calcium phosphate cement scaffolds for bone tissue engineering: in vitro study. Acta Cir Bras. 2011 Feb;26(1):7-11 Authors: Silva TS, Primo BT, Silva Júnior AN, Machado DC, Viezzer C, Santos LA Purpose: To evaluate the ability of macroporous tricalcium phosphate cement (CPC) scaffolds to enable the adhesion, proliferation, and differentiation of mesenchymal stem cells derived from human bone marrow. Methods: Cells from the iliac crest of an adult human donor were processed and cultured on macroporous CPC discs. Paraffin spheres sized between 100 and 250µm were used as porogens. Cells were cultured for 5, 10, and 15 days. Next, we assessed cells' behavior and morphology on the biomaterial by scanning electron microscopy. The expression levels of the BGLA and SSP1 genes and the alkaline phosphatase (ALP) activity were quantified by the quantitative real-time polymerase chain reaction technique (QT-PCR) using the fluorophore SYBR GREEN®. Results: QT-PCR detected the expression of the BGLA and SSP1 genes and the ALP activity in the periods of 10 and 15 days of culture. Thus, we found out that there was cell proliferation and differentiation in osteogenic cells. Conclusion: Macroporous CPC, with pore sized between 100 and 250µm and developed using paraffin spheres, enables adhesion, proliferation, and differentiation of mesenchymal stem cells in osteogenic cells and can be used as a scaffold for bone tissue engineering. PMID: 21271197 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regulation of Nm23-H1 and cell invasiveness by Kaposi's sarcoma-associated herpesvirus. J Virol. 2011 Jan 26; Authors: Qin Z, Dai L, Toole B, Robertson E, Parsons C The Kaposi's sarcoma-associated herpesvirus (KSHV) is the causative agent of Kaposi's sarcoma (KS), and the induction of an invasive cellular phenotype by KSHV following de novo infection is an important pathogenic component mediating tumor progression. The metastasis suppressor gene known as Nm23-H1 regulates tumor cell invasiveness, but whether KSHV itself regulates Nm23-H1 expression or subcellular localization, and whether this impacts cell invasiveness, has not been established. We found that KSHV increases expression and nuclear translocation of Nm23-H1, and that nuclear translocation of Nm23-H1 is regulated by the KSHV-encoded latency-associated nuclear antigen (LANA). Moreover, activation of the Ras-BRaf-MAPK signal transduction pathway, secretion of pro-migratory factors associated with this pathway, and cell invasiveness are dependent on KSHV regulation of Nm23-H1. Finally, induction of cytoplasmic overexpression of Nm23-H1 using a pharmacologic inhibitor of DNA methylation reduced KSHV-associated Ras-BRaf-MAPK pathway activation and suppressed KSHV-induced invasiveness. These data provide the first evidence for KSHV regulation of Nm23-H1 as a mechanism for KSHV induction of an invasive cellular phenotype and support the potential utility of targeting Nm23-H1 as a therapeutic approach for the treatment of KS. PMID: 21270158 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regulation of cellular responses to macroporous inorganic films prepared by the inverse-opal method. Colloids Surf B Biointerfaces. 2011 Jan 7; Authors: Orita T, Tomita M, Kato K Regenerative medicine for repairing damaged body tissues has recently become critically important. Cell culture scaffolds are required for the control of cell attachment, proliferation, and differentiation in in vitro cell cultures. A new strategy to control cell adhesion, morphology, and proliferation was developed by culturing mouse osteoblast-like MC3T3-E1 cells on novel cell culture scaffolds fabricated using ordered nanometer-sized pores (100, 300, 500, and 1000nm). Results of this study indicate that after 72h of incubation, the number of cells cultured on a silica film with a pore size of 1000nm was similar to or slightly lower than that cultured on a non-porous control silica film. Films with 100-500nm pore sizes, however, resulted in the cell growth inhibition. Morphology of the cultured cells revealed increased elongation and the formation of actin stress fibers was virtually absent on macroporous silica films with 100-500nm pore size. Vinculin molecules expressed in cells cultured on the non-porous silica films showed many clear focal adhesions, whereas focal contacts were insufficiently formed in cells cultured on macroporous films. The influence of hydroxyapatite (HAp) and alumina scaffolds on the behavior of MC3T3-E1 cells was also evaluated. The proliferation rate of MC3T3-E1 cells cultured on HAp films with 1000nm pore size was increased to approximately 20% above than that obtained of cells cultured on non-porous HAp films. These results demonstrate that the pore size and constituents of films play a role in controlling the morphology and proliferation rate of MC3T3-E1cells. PMID: 21273052 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Portable nanofiber meshes dictate cell orientation throughout three dimensional hydrogels. Nanomedicine. 2011 Jan 24; Authors: Yang Y, Wimpenny I, Ahearne M In this study, a new technique which controls individual cell orientation via nanofiber meshes within three dimensional (3D) hydrogels is reported. Highly aligned and fragile electrospun nanofibers (av. ϕ500 nm) are manufactured into portable and handleable meshes with average line density of 45 nanofiber/100 μm and thickness ranging between 0.5 and 3.0 μm. Through a facile and reproducible fabrication process, the nanofiber meshes can be incorporated into 3D hydrogels via a bottom-up, layer-by-layer assembly process, resulting in macroscopic and highly organized scaffolds. The nanofibers dictated the orientation of the cytoskeleton of individual cells in a very precise manner, allowing altering the orientation of a cell population throughout the thickness of the hydrogel. Addition of nanofibers affected cell phenotype and protein synthesis. This nanofiber-cell-hydrogel composite enables replication of the cellular and matrix architecture found in many natural tissues, offering a novel protocol for electrospun nanofibers in regenerative medicine and bioengineering. PMID: 21272664 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A comparison of the tissue response to chronically implanted Parylene-C-coated and uncoated planar silicon microelectrode arrays in rat cortex. Biomaterials. 2010 Dec;31(35):9163-72 Authors: Winslow BD, Christensen MB, Yang WK, Solzbacher F, Tresco PA In this study we employed a quantitative immunohistochemical approach to compare the brain tissue response to planar silicon microelectrode arrays that were conformally coated with Parylene-C to uncoated controls at 2, 4, and 12 weeks following implantation into the cortex of adult male Sprague-Dawley rats. We did not find any difference in the relative intensity or the spatial distribution of neuronal or glial markers over the indwelling period, even though Parylene-C-coated substrates supported significantly less cell attachment, indicating that the foreign body response to planar silicon microelectrode arrays has little to do with the composition or decomposition of the silicon electrode. Moreover, our results suggest that changes in microelectrode surface chemistry do not have a strong influence on the cytoarchitectural changes that accompany the brain foreign body response to planar silicon microelectrode arrays. Our quantitative comparison over the indwelling period does not support progressive increases in astrocyte encapsulation and/or progressive neuronal loss in the recording zone as dominant failure mechanisms of the type of chronic recording device. Finally, we found evidence of two potentially new failure mechanisms that were associated with CD68 immunoreactivity including demyelination of adjacent neurons and BBB breakdown surrounding implanted electrodes at long indwelling times. PMID: 20561678 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Electrostatic effects on nanofiber formation of self-assembling peptide amphiphiles. J Colloid Interface Sci. 2011 Jan 1; Authors: Toksoz S, Mammadov R, Tekinay AB, Guler MO Self-assembling peptide amphiphile molecules have been of interest to various tissue engineering studies. These molecules self-assemble into nanofibers which organize into three-dimensional networks to form hydrocolloid systems mimicking the extracellular matrix. The formation of nanofibers is affected by the electrostatic interactions among the peptides. In this work, we studied the effect of charged groups on the peptides on nanofiber formation. The self-assembly process was studied by pH and zeta potential measurements, FT-IR, circular dichroism, rheology, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. The aggregation of the peptides was triggered upon neutralization of the charged residues by pH change or addition of electrolyte or biomacromolecules. Understanding the controlled formation of the hydrocolloid gels composed of peptide amphiphile nanofibers can lead us to develop in situ gel forming bioactive collagen mimetic nanofibers for various tissue engineering studies including bioactive surface coatings. PMID: 21269637 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of psoralen on bone formation. J Orthop Res. 2011 Feb;29(2):158-64 Authors: Wong RW, Rabie AB To compare the amount of new bone and bone cells produced by psoralen in collagen matrix to that produced by collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm were created in the parietal bone of nine New Zealand White rabbits. Six defects were grafted with psoralen mixed with collagen matrix. Six defects were grafted with collagen matrix alone (negative control--collagen) and six were left empty (negative control--empty). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells were made on 100 sections (50 sections for each group) using image analysis. A total of 454% more new bone was present in defects grafted with psoralen in collagen matrix than those grafted with collagen matrix. No bone was formed in the negative control--empty group. The amount of bone forming osteoblasts was also significantly greater in the psoralen group than the negative control--collagen group. Psoralen in collagen matrix has the effect of increasing new bone formation locally in vivo. Psoralen in collagen matrix can be developed as a bone graft material. PMID: 20196083 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Hepatocyte differentiation of human fibroblasts from cirrhotic liver in vitro and in vivo. Hepatobiliary Pancreat Dis Int. 2011 Feb;10(1):55-63 Authors: Sun YL, Yin SY, Zhou L, Xie HY, Zhang F, Wu LM, Zheng SS BACKGROUND: Mesenchymal stem cells (MSCs) and fibroblasts have intimate relationships, and the phenotypic homology between fibroblasts and MSCs has been recently described. The aim of this study was to investigate the hepatic differentiating potential of human fibroblasts in cirrhotic liver. METHODS: The phenotypes of fibroblasts in cirrhotic liver were labeled by biological methods. After that, the differentiation potential of these fibroblasts in vitro was characterized in terms of liver-specific gene and protein expression. Finally, an animal model of hepatocyte regeneration in severe combined immunodeficient (SCID) mice was created by retrorsine injection and partial hepatectomy, and the expression of human hepatocyte proteins in SCID mouse livers was checked by immunohistochemical analysis after fibroblast administration. RESULTS: Surface immunophenotyping revealed that a minority of fibroblasts expressed markers of MSCs and hepatic epithelial cytokeratins as well as alpha-smooth muscle actin, but homogeneously expressed vimentin, desmin, prolyl 4-hydroxylase and fibronectin. These fibroblasts presented the characteristics of hepatocytes in vitro and differentiated directly into functional hepatocytes in the liver of hepatecto-mized SCID mice. CONCLUSIONS: This study demonstrated that fibroblasts in cirrhotic liver have the potential to differentiate into hepatocyte-like cells in vitro and in vivo. Our findings infer that hepatic differentiation of fibroblasts may serve as a new target for reversion of liver fibrosis and a cell source for tissue engineering. PMID: 21269936 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Human bone marrow and adipose tissue mesenchymal stem cells: a user's guide. Stem Cells Dev. 2010 Oct;19(10):1449-70 Authors: Mosna F, Sensebé L, Krampera M Mesenchymal stem cells (MSCs) are adult stem cells that hold great promise in the field of regenerative medicine. They can be isolated from almost any tissue of the body and display, after expansion, very similar properties and minor differences, probably due to their microenvironment of origin. Expansion in vitro can be obtained in cytokine-free, serum-enriched media, as well as in serum-free, basic fibroblast growth factor-enriched media. A detailed immunophenotypic analysis is required to test the purity of the preparation, but no unique distinguishing marker has been described as yet. Functional assays, that is, differentiation studies in vitro, are needed to prove multilineage differentiation of expanded cells, and demonstration of pluripotency is necessary to identify most immature precursors. MSCs show powerful immunomodulative properties toward most of the cells of the immune system: this strengthens the theoretical rationale for their use also in an allogeneic setting across the major histocompatibility complex (MHC) immunological barriers. Systemic intravenous injection and local use have been tried: after systemic injection, MSCs show a high degree of chemotaxis based on pro-inflammatory cytokines, and localize at inflamed and neoplastic tissues; local regeneration has been improved using synthetic, as well as organic scaffolds. On the other hand, inadequate heterotopic in vivo differentiation and neoplastic transformation are potential risks of this form of cell therapy, even if evidence of this sort has been collected only from studies in mice, and generally after prolonged in vitro expansion. This review tries to provide a detailed technical overview of the methods used for human bone-marrow (BM)-derived and adipose-tissue (AT)-derived MSC isolation, in vitro expansion, and characterization for tissue repair. We chose to use BM-MSCs as a model to describe techniques that have been used for MSC isolation and expansion from very different sources, and AT-MSCs as an example of a reliable and increasingly common alternative source. PMID: 20486777 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Bridging the gap: bone marrow aspiration concentrate reduces autologous bone grafting in osseous defects. J Orthop Res. 2011 Feb;29(2):173-80 Authors: Jäger M, Herten M, Fochtmann U, Fischer J, Hernigou P, Zilkens C, Hendrich C, Krauspe R Although autologous bone grafting represents an effective tool to induce osteogenic regeneration in local bone defects or pseudarthroses, it is associated with significant donor site morbidity and limited by the amount available for grafting. We investigate the potency of bone marrow aspiration concentrate (BMAC) to augment bone grafting and support bone healing. The functional and radiographic outcome of 39 patients with volumetric bone deficiencies treated with BMAC are presented and evaluated in a prospective clinical trial. A collagen sponge (Col) served as scaffold in 12 patients and a bovine hydroxyapatite (HA) was applied in the other 27 individuals. The minimal follow-up was 6 months. Clinical and radiographic findings were completed by in vitro data. All patients showed new bone formation in radiographs during follow-up. However, two patients underwent revision surgery due to a lack in bone healing. In contrast to the Col group, the postoperative bone formation appeared earlier in the HA group (HA group: 6.8 weeks vs. Col group 13.6 weeks). Complete bone healing was achieved in the HA group after 17.3 weeks compared to 22.4 weeks in the Col group. The average concentration factor of BMAC was 5.2 (SD 1.3). Flow cytometry confirmed the mesenchymal nature of the cells. Cells from BMAC created earlier and larger colonies of forming units fibroblasts (CFU-F) compared to cells from bone marrow aspirate. BMAC combined with HA can reduce the time needed for healing of bone defects when compared to BMAC in combination with collagen sponge. PMID: 20740672 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Non-invasive imaging of human embryos before embryonic genome activation predicts development to the blastocyst stage. Nat Biotechnol. 2010 Oct;28(10):1115-21 Authors: Wong CC, Loewke KE, Bossert NL, Behr B, De Jonge CJ, Baer TM, Reijo Pera RA We report studies of preimplantation human embryo development that correlate time-lapse image analysis and gene expression profiling. By examining a large set of zygotes from in vitro fertilization (IVF), we find that success in progression to the blastocyst stage can be predicted with >93% sensitivity and specificity by measuring three dynamic, noninvasive imaging parameters by day 2 after fertilization, before embryonic genome activation (EGA). These parameters can be reliably monitored by automated image analysis, confirming that successful development follows a set of carefully orchestrated and predictable events. Moreover, we show that imaging phenotypes reflect molecular programs of the embryo and of individual blastomeres. Single-cell gene expression analysis reveals that blastomeres develop cell autonomously, with some cells advancing to EGA and others arresting. These studies indicate that success and failure in human embryo development is largely determined before EGA. Our methods and algorithms may provide an approach for early diagnosis of embryo potential in assisted reproduction. PMID: 20890283 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Synergistic Enhancement of Human Bone Marrow Stromal Cell Proliferation and Osteogenic Differentiation on BMP-2 Derived and RGD Peptide Concentration Gradients. Acta Biomater. 2011 Jan 24; Authors: Moore NM, Lin NJ, Gallant ND, Becker ML Rational design of bioactive tissue engineered scaffolds for directing bone regeneration in vivo requires a comprehensive understanding of cell interactions with the immobilized bioactive molecules. In the current study, substrates possessing gradient concentrations of immobilized peptides were used to measure the concentration dependent proliferation and osteogenic differentiation of human bone marrow stromal cells (hBMSC). Two bioactive peptides, one derived from extracellular matrix protein (ECM), GRGDS, and one from bone morphogenic protein-2 (BMP-2), KIPKASSVPTELSAISTLYL, were found to synergistically enhance cell proliferation, upregulate osteogenic mRNA markers bone sialoprotein (BSP) and Runt related transcription factor 2 (RUNX2), and produce mineralization at densities greater than 130 pmol/cm(2) (65 pmol/cm(2) for each peptide). In addition, COOH terminated SAM alone led to upregulated BSP mRNA levels at densities above 200 pmol/cm(2) and increased cell proliferation from day 3 to day 14. Taking further advantage of both the synergistic potentials and concentration dependent activities of ECM and growth factor derived peptides on proliferative activity and osteogenic differentiation, without the need for additional osteogenic supplements, will enable the successful incorporation of the bioactive species into bio-relevant tissue engineering scaffolds. PMID: 21272672 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | [Preparation of a decellularized rat liver scaffold and its biocompatibility.] Nan Fang Yi Ke Da Xue Xue Bao. 2011 Jan 20;31(1):69-72 Authors: Pan MX, Cheng Y, Wang Y, He GL, Hu PY, Gao Y OBJECTIVE: To develop a novel method for preparing decellularized liver biological scaffold (DLBS) for liver tissue engineering. METHODS: DLBS was prepared by treatment of rat livers with detergent and enzymatic cell extraction and observed under optical and scanning electron microscopes. To assess the biocompatibility of the product, C3A cells and bone marrow-derived mesenchymal cells (BM-MSCs) were cocultured with DLBS as the scaffold, and the effect of DLBS on the proliferation of C3A cells was evaluated by MTT assay. DLBS was also implanted under the dorsal skin of SD rats to evaluate the tissue biocompatibility of this material. RESULTS: Application of the detergent and enzymatic extraction allowed full extraction of the cells in the liver, leaving an extracellular matrix scaffold composed mainly of collagen and elastic fibrin. The coculture experiment showed that C3A cells and BM-MSCs could grow on and adhere to DLBS. The result of MTT assay showed that DLBS could promote the proliferation of C3A cells. CONCLUSION: This cell-free DLBS, which retains intact extracellular matrix and promotes cell attachment, proliferation, growth and differentiation, can be an ideal biological matrix scaffold material. PMID: 21269960 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Substrate elasticity provides mechanical signals for the expansion of hemopoietic stem and progenitor cells. Nat Biotechnol. 2010 Oct;28(10):1123-8 Authors: Holst J, Watson S, Lord MS, Eamegdool SS, Bax DV, Nivison-Smith LB, Kondyurin A, Ma L, Oberhauser AF, Weiss AS, Rasko JE Surprisingly little is known about the effects of the physical microenvironment on hemopoietic stem and progenitor cells. To explore the physical effects of matrix elasticity on well-characterized primitive hemopoietic cells, we made use of a uniquely elastic biomaterial, tropoelastin. Culturing mouse or human hemopoietic cells on a tropoelastin substrate led to a two- to threefold expansion of undifferentiated cells, including progenitors and mouse stem cells. Treatment with cytokines in the presence of tropoelastin had an additive effect on this expansion. These biological effects required substrate elasticity, as neither truncated nor cross-linked tropoelastin reproduced the phenomenon, and inhibition of mechanotransduction abrogated the effects. Our data suggest that substrate elasticity and tensegrity are important mechanisms influencing hemopoietic stem and progenitor cell subsets and could be exploited to facilitate cell culture. PMID: 20890282 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The influence of a bisphosphonate on bone generation determined using a chick-femur model. Int Endod J. 2011 Jan 28; Authors: Wei LL, Gellynck K, Ng YL, Gulabivala K, Buxton P Wei L-L, Gellynck K, Ng Y-L, Gulabivala K, Buxton P. The influence of a bisphosphonate on bone generation determined using a chick-femur model. International Endodontic Journal. ABSTRACT: Aim To determine the direct influence of a bisphosphonate (pamidronate) delivered by one of two carriers, on bone generation in chick-femurs supported by chick egg chorio-allantoic membranes. Methodology Twenty chick femurs freshly harvested from fertilized eggs were randomly allocated to two groups: (i) Affi-Gel blue bead carrier (n = 10); and (ii) hydroxyapatite bead carrier (n = 10). The femurs in each group were further randomly divided into control (n = 4) and experimental (n = 6) subgroups. Carriers charged with PBS solution or 0.1 M pamidronate were delivered into the bone marrow of each femur at its mid-portion through a needle puncture. Each femur was then grafted onto the chorio-allantoic membrane of a chick egg and incubated for 7 days. Each experimental and control subgroup femur yielded four histological sections at the puncture site, constituting the test and inter-bone controls. In addition, two histological sections were also obtained from 400 to 450 μm away from each end of the experimental puncture site to act as the intra-bone controls. Bone generation was quantified and the ratio of cross-sectional area of bone marrow to circumference of bone (outcome measure) was determined using a software package, Image-Pro(®) Plus. The data were analysed using Mann-Whitney tests and Wilcoxon signed rank tests. Results The outcome ratio in the test group was significantly (P < 0.001) smaller than both the inter-bone and intra-bone control groups. There was evidence of increased bone formation directly over the pamidronate-charged carriers. Conclusions The test model established that pamidronate had a positive effect on bone generation over a period of 7 days, regardless of the carrier type. PMID: 21272044 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Thermal, dynamic mechanical, and dielectric analyses of some polyurethane biocomposites. J Biomater Appl. 2011 Jan 27; Authors: Macocinschi D, Filip D, Vlad S, Cristea M, Musteata V, Ibanescu S Polymer biocomposites based on segmented poly(ester urethane) and extracellular matrix components have been prepared for the development of tissue engineering applications with improved biological characteristics of the materials in contact with blood and tissues for long periods. Thermal, dynamical, and dielectrical analyses were employed to study the molecular dynamics of these materials and the influence of changing the physical network morphology and hydrogen bond interactions accompanied by phase transitions, interfacial effects, and polarization or conductivity. All phenomena that concur in the tested materials are evaluated by cross-examination of the dynamic mechanical characteristic properties (storage modulus, loss modulus, and loss factor) and dielectric properties (relative permittivity, relative loss factor, and loss tangent) as a function of temperature. Comparative aspects were elucidated by calculating the apparent activation energies of multiplex experiments. PMID: 21273260 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Characterizations of Chondrocyte Attachment and Proliferation Scaffolds of PLLA and PBSA for Use in Cartilage Tissue Engineering. J Biomater Appl. 2011 Jan 27; Authors: Wei JD, Tseng H, Chen ET, Hung CH, Liang YC, Sheu MT, Chen CH The influence of physical characteristics of electrospun three-dimensional (3D) fibrous scaffolds based on polybutylene succinate-co-adipate (PBSA) and poly L-lactic acid (PLLA) on the culture of primary human chondrocytes (PHCs) in terms of cell attachment, proliferation, and re-differentiation was investigated. Physical characteristics assessed for two polymers electrospun at two different delivery rates (PBSA-3, PBSA-16, PLLA-3, and PLLA-16) including average fiber diameter, average pore diameter, porosity, and contact angle. Results demonstrated that 3D fibrous scaffolds are better for PHCs' attachment than two-dimensional (2D) casting films made of the same polymeric materials. It was also found that 3D fibrous scaffolds are appropriate architecture for the proliferation of PHCs than 2D casting films and dependent upon the polymer used. Histological analysis revealed that a significant amount of PHC was found to be growing only within layers of PLLA fibrous scaffolds. The mitochondrial ribonucleic acid (mRNA) expression of both aggrecan and type II collagen by PHCs cultured in tissue culture polystyrene for 28 days decreased significantly. The mRNA expression of both aggrecan and type II collagen by PHCs cultured in PBSA scaffolds increased from 14 to 28 days, whereas only mRNA expression of aggrecan cultured in both PLLA scaffolds increased from 14 to 28 days. PMID: 21273264 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Interferon-α in acute myeloid leukemia: an old drug revisited. Leukemia. 2011 Jan 28; Authors: Anguille S, Lion E, Willemen Y, Van Tendeloo VF, Berneman ZN, Smits EL Interferon-α (IFN-α), a type I IFN, is a well-known antitumoral agent. The investigation of its clinical properties in acute myeloid leukemia (AML) has been prompted by its pleiotropic antiproliferative and immune effects. So far, integration of IFN-α in the therapeutic arsenal against AML has been modest in view of the divergent results of clinical trials. Recent insights into the key pharmacokinetic determinants of the clinical efficacy of IFN along with advances in its pharmaceutical formulation, have sparked renewed interest in its use. This paper reviews the possible applicability of IFN-α in the treatment of AML and provides a rational basis to re-explore its efficacy in clinical trials.Leukemia advance online publication, 28 January 2011; doi:10.1038/leu.2010.324. PMID: 21274002 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Origin and hierarchy of basal lamina-forming and -non-forming myogenic cells in mouse skeletal muscle in relation to adhesive capacity and Pax7 expression in vitro. Cell Tissue Res. 2011 Jan 29; Authors: Tamaki T, Tono K, Uchiyama Y, Okada Y, Masuda M, Soeda S, Nitta M, Akatsuka A As a novel approach to distinguish skeletal myogenic cell populations, basal lamina (BL) formation of myogenic cells was examined in the mouse compensatory enlarged plantaris muscles in vivo and in fiber-bundle cultures in vitro. MyoD(+) myogenic cells located inside the regenerative muscle fiber BL were laminin(-) but interstitial MyoD(+) cells were laminin(+). This was also confirmed by electron microscopy as structural BL formation. Similar trends were observed in the fiber-bundle cultures including satellite cells and interstitial myogenic cells and laminin(+) myogenic cells predominantly showed non-adhesive (non-Ad) behavior with Pax7(-), whereas laminin(-) cells were adhesive (Ad) with Pax7(+). Moreover, non-Ad/laminin(+) and Ad/laminin(-) myotubes were also observed and the former type showed spontaneous contractions, while the latter type did not. The origin and hierarchy of Ad/Pax7(+)/laminin(-) and non-Ad/Pax7(-)/laminin(+) myogenic cells were also examined using skeletal muscle interstitium-derived CD34(+)/45(-) (Sk-34) and CD34(-)/45(-) (Sk-DN) multipotent stem cells, which were composed of non-committed myogenic cells with a few (<1%) Pax7(+) cells in the Sk-DN cells at fresh isolation. Both cell types were separated by Ad/non-Ad capacity in repetitive culture. As expected, both Ad/Pax7(+)/laminin(-) and non-Ad/Pax7(-)/laminin(+) myogenic cells consistently appeared in the Ad and non-Ad cell culture. However, Ad/Pax7(+)/laminin(-) cells were repeatedly detected in the non-Ad cell culture, while the opposite phenomenon did not occur. This indicates that the source of non-Ad/ Pax7(-)/laminin(+) myogenic cells was present in the Sk-34 and Sk-DN stem cells and they were able to produce Ad/ Pax7(+)/ laminin(-) myogenic cells during myogenesis as primary myoblasts and situated hierarchically upstream of the latter cells. PMID: 21274567 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Stem Cell Therapy as an Emerging Paradigm for Stroke (STEPS) II. Stroke. 2011 Jan 27; Authors: Savitz SI, Chopp M, Deans R, Carmichael ST, Phinney D, Wechsler L Abstract Cell-based therapies represent a new therapeutic approach for stroke. In 2007, investigators from academia, industry leaders, and members of the National Institutes of Health crafted recommendations to facilitate the translational development of cellular therapies as a novel, emerging modality for stroke from animal studies to clinical trials. This meeting was called Stem Cell Therapies as an Emerging Paradigm in Stroke (STEPS) and was modeled on the format of the Stroke Therapy Academic Industry Roundtable (STAIR) meetings. Since publication of the original STEPS guidelines, there has been an explosive growth in the number of cellular products and in the number of new laboratory discoveries that impact the safety and potential efficacy of cell therapies for stroke. Any successful development of a cell product will need to take into consideration several factors, including the preclinical safety and efficacy profile, cell characterization, delivery route, in vivo biodistribution, and mechanism of action. In 2010, a second meeting called STEPS 2 was held to bring together clinical and basic science researchers with industry, regulatory, and National Institutes of Health representatives. At this meeting, participants identified critical gaps in knowledge and research areas that require further studies, updated prior guidelines, and drafted new recommendations to create a framework to guide future investigations in cell-based therapies for stroke. PMID: 21273569 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Structural Characteristics of Small Intestinal Submucosa Constructs Dictate In Vivo Incorporation and Angiogenic Response. J Biomater Appl. 2011 Jan 27; Authors: Janis AD, Johnson CC, Ernst DM, Brightman AO The rate of angiogenesis and cellular infiltration into degradable biomaterials determines scaffold persistence in vivo. The ability to tune the degradation properties of naturally derived biomaterials has been a popular goal in tissue engineering, yet has often depended on chemical crosslinking. Small intestinal submucosa (SIS) is a naturally derived, collagen-based, bioactive scaffold that has broad clinical success in many therapeutic applications. Two methods for producing multilayer, non-crosslinked SIS constructs were compared in vitro and in vivo. Traditional and cryo SEM, mercury intrusion porosimetry, and a novel enzymatic degradation assay determined that lyophilization produced an open, porous scaffold, in contrast to the collapsed, denser structure of SIS constructs produced using a vacuum press process. The angiogenic responses to lyophilized and vacuum-pressed SIS constructs were evaluated in vivo using a subcutaneous implant assay in mice. Explanted samples were compared after 7 and 21 days using fluorescence microangiography and light microscopy. Capacity of the implant neovasculature was also determined. These experiments revealed that the lyophilized SIS was infiltrated and vascularized more rapidly than the vacuum pressed. These data demonstrate the tunable incorporation of a non-crosslinked ECM-based biomaterial, which may have implications for the persistence of this degradable, scaffold in tissue engineering. PMID: 21273257 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | CD45 Deficiency Drives Amyloid-{beta} Peptide Oligomers and Neuronal Loss in Alzheimer's Disease Mice. J Neurosci. 2011 Jan 26;31(4):1355-1365 Authors: Zhu Y, Hou H, Rezai-Zadeh K, Giunta B, Ruscin A, Gemma C, Jin J, Dragicevic N, Bradshaw P, Rasool S, Glabe CG, Ehrhart J, Bickford P, Mori T, Obregon D, Town T, Tan J Converging lines of evidence indicate dysregulation of the key immunoregulatory molecule CD45 (also known as leukocyte common antigen) in Alzheimer's disease (AD). We report that transgenic mice overproducing amyloid-β peptide (Aβ) but deficient in CD45 (PSAPP/CD45(-/-) mice) faithfully recapitulate AD neuropathology. Specifically, we find increased abundance of cerebral intracellular and extracellular soluble oligomeric and insoluble Aβ, decreased plasma soluble Aβ, increased abundance of microglial neurotoxic cytokines tumor necrosis factor-α and interleukin-1β, and neuronal loss in PSAPP/CD45(-/-) mice compared with CD45-sufficient PSAPP littermates (bearing mutant human amyloid precursor protein and mutant human presenilin-1 transgenes). After CD45 ablation, in vitro and in vivo studies demonstrate an anti-Aβ phagocytic but proinflammatory microglial phenotype. This form of microglial activation occurs with elevated Aβ oligomers and neural injury and loss as determined by decreased ratio of anti-apoptotic Bcl-xL to proapoptotic Bax, increased activated caspase-3, mitochondrial dysfunction, and loss of cortical neurons in PSAPP/CD45(-/-) mice. These data show that deficiency in CD45 activity leads to brain accumulation of neurotoxic Aβ oligomers and validate CD45-mediated microglial clearance of oligomeric Aβ as a novel AD therapeutic target. PMID: 21273420 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | A Peptide Mimetic of the Connexin43 Carboxyl Terminus Reduces Gap Junction Remodeling and Induced Arrhythmia Following Ventricular Injury. Circ Res. 2011 Jan 27; Authors: O'Quinn MP, Palatinus JA, Harris BS, Hewett KW, Gourdie RG Rationale: Remodeling of connexin (Cx)43 gap junctions (GJs) is linked to ventricular arrhythmia. Objectives: A peptide mimetic of the carboxyl terminal (CT) of Cx43, incorporating a postsynaptic density-95/disks-large/ZO-1 (PDZ)-binding domain, reduces Cx43/ZO-1 interaction and GJ size remodeling in vitro. Here, we determined: (1) whether the Cx43-CT mimetic αCT1 altered GJ remodeling following left ventricular (LV) injury in vivo; (2) whether αCT1 affected arrhythmic propensity; and (3) the mechanism of αCT1 effects on arrhythmogenicity and GJ remodeling. Methods and Results: A cryoinjury model generating a reproducible wound and injury border zone (IBZ) in the LV was used. Adherent methylcellulose patches formulated to locally release αCT1 (<48 hours) were placed on cryoinjuries. Relative to controls, Cx43/ZO-1 colocalization in the IBZ was reduced by αCT1 by 24 hours after injury. Programmed electric stimulation ex vivo and optical mapping of voltage transients indicated that peptide-treated hearts showed reduced inducible arrhythmias and increased ventricular depolarization rates 7 to 9 days after injury. At 24 hours and 1 week after injury, αCT1-treated hearts maintained Cx43 in intercalated disks (IDs) in the IBZ, whereas by 1 week after injury, controls demonstrated Cx43 remodeling from IDs to lateralized distributions. Over a postinjury time course of 1 week, αCT1-treated IBZs showed increased Cx43 phosphorylation at serine368 (Cx43-pS368) relative to control tissues. In biochemical assays, αCT1 promoted phosphorylation of serine368 by protein kinase (PK)C-ε in a dose-dependent manner that was modulated by, but did not require ZO-1 PDZ2. Conclusions: αCT1 increases Cx43-pS368 in vitro in a PKC-ε-dependent manner and in the IBZ in vivo acutely following ventricular injury. αCT1-mediated increase in Cx43-pS368 phosphorylation may contribute to reductions in inducible-arrhythmia following injury. PMID: 21273554 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Low-level laser therapy: a useful technique for enhancing the proliferation of various cultured cells. Lasers Med Sci. 2011 Jan 28; Authors: Alghamdi KM, Kumar A, Moussa NA The aim of this work is to review the available literature on the details of low-level laser therapy (LLLT) use for the enhancement of the proliferation of various cultured cell lines including stem cells. A cell culture is one of the most useful techniques in science, particularly in the production of viral vaccines and hybrid cell lines. However, the growth rate of some of the much-needed mammalian cells is slow. LLLT can enhance the proliferation rate of various cell lines. Literature review from 1923 to 2010. By investigating the outcome of LLLT on cell cultures, many articles report that it produces higher rates of ATP, RNA, and DNA synthesis in stem cells and other cell lines. Thus, LLLT improves the proliferation of the cells without causing any cytotoxic effects. Mainly, helium neon and gallium-aluminum-arsenide (Ga-Al-As) lasers are used for LLLT on cultured cells. The results of LLLT also vary according to the applied energy density and wavelengths to which the target cells are subjected. This review suggests that an energy density value of 0.5 to 4.0 J/cm(2) and a visible spectrum ranging from 600 to 700 nm of LLLT are very helpful in enhancing the proliferation rate of various cell lines. With the appropriate use of LLLT, the proliferation rate of cultured cells, including stem cells, can be increased, which would be very useful in tissue engineering and regenerative medicine. PMID: 21274733 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The use of whole organ decellularization for the generation of a vascularized liver organoid. Hepatology. 2011 Feb;53(2):604-617 Authors: Baptista PM, Siddiqui MM, Lozier G, Rodriguez SR, Atala A, Soker S A major roadblock to successful organ bioengineering is the need for a functional vascular network within the engineered tissue. Here, we describe the fabrication of three-dimensional, naturally derived scaffolds with an intact vascular tree. Livers from different species were perfused with detergent to selectively remove the cellular components of the tissue while preserving the extracellular matrix components and the intact vascular network. The decellularized vascular network was able to withstand fluid flow that entered through a central inlet vessel, branched into an extensive capillary bed, and coalesced into a single outlet vessel. The vascular network was used to reseed the scaffolds with human fetal liver and endothelial cells. These cells engrafted in their putative native locations within the decellularized organ and displayed typical endothelial, hepatic, and biliary epithelial markers, thus creating a liver-like tissue in vitro. Conclusion: These results represent a significant advancement in the bioengineering of whole organs. This technology may provide the necessary tools to produce the first fully functional bioengineered livers for organ transplantation and drug discovery. (HEPATOLOGY 2011;53:604-617). PMID: 21274881 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Modeling and therapy of human liver diseases using induced pluripotent stem cells: How far have we come? Hepatology. 2011 Feb;53(2):708-711 Authors: Soto-Gutierrez A, Tafaleng E, Kelly V, Roy-Chowdhury J, Fox IJ PMID: 21274892 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Development of conical soluble phosphate glass fibers for directional tissue growth. J Biomater Appl. 2011 Jan 27; Authors: Alekseeva T, Neel EA, Knowles JC, Brown RA One of the challenges of tissue engineering is the regulation of vascularization and innervations of the implant by the host. Here, we propose that using soluble phosphate glass (SPG) fibers, incorporated in dense collagen constructs will allow us to control the rate and direction of tissue ingrowth. The idea here was to generate channels with tailored direction using conical phosphate glass fibers. The changing surface area-to-mass ratio of conical fibers will make them to dissolve faster from their narrow ends opening up channels in that direction ahead of any ingrowing cells. In this study, we show that SPG fibers can be manipulated to produce conical shape fibers using graded dissolution. Our result shows that 40 µm fibers of composition ratio 0.5 (P(2)O(5)):0.25 (CaO):0.25 (Na(2)O) and dissolution time of 8-10 h have a mean reduction in fiber diameter of 8.85 ± 2.8 µm over 19.5 mm fiber length, i.e., a mean rate of 0.5 µm/mm (n = 20) change. These conically shaped fibers can also be manipulated and potentially used to promote uniaxial cell-tissue ingrowth for improved innervations and vascularization of tissue engineered constructs. PMID: 21273258 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
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