|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Laryngeal transplantation in minipigs: vascular, myologic and functional outcomes. Eur Arch Otorhinolaryngol. 2010 Sep 15; Authors: Birchall MA, Kingham PJ, Murison PJ, Ayling SM, Burt R, Mitchard L, Jones A, Lear P, Stokes CR, Terenghi G, Bailey M, Macchiarini P There is no effective way of replacing all the functions of the larynx in those requiring laryngectomy. Regenerative medicine offers promise, but cannot presently deliver implants with functioning neuromuscular units. A single well-documented laryngeal transplant in man was a qualified success, but more information is required before clinical trials may be proposed. We studied the early response of the larynx to laryngeal transplantation between 17 pairs of NIH minipigs full matched at the MHC2 locus. Following iterative technical improvements, pigs had good swallowing and a patent airway at 1 week. No significant changes in mucosal blood flux were observed compared with pre-operative measurements. Changes in muscle morphology and fibre phenotype were observed in transplant muscles retrieved after 7 days: the levels of fast and slow myosin heavy chain (MyHC) protein were reduced and embryonic MyHC was up regulated consistent with denervation induced atrophy. At 1 week laryngeal transplantation can result in good swallowing, and is not associated with clinical evidence of ischemia-reperfusion injury in MHC-matched pigs. PMID: 20842506 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Regeneration of the vascular compartment. Herz. 2010 Aug;35(5):342-351 Authors: Becher MU, Nickenig G, Werner N Throughout life, damage to the vascular endothelium is pivotal in the development of cardiovascular disease. Therefore, a detailed understanding of the underlying mechanisms involved in endothelial cell restoration is of fundamental importance for preventive and therapeutic concepts in cardiovascular disease. The goal of regenerative medicine is the use of tissue-specific progenitor cells for a more effective repair process with reduction of fibrocellular remodelling, fibrosis and loss of functional properties.According to the hitherto assumed primary model of endothelial regeneration only adjacent and intact mature endothelial cells replace damaged endothelium. Since Asahara and colleagues first described that a peripheral blood mononuclear cell population was able to differentiate into endothelial cells in vitro and incorporate into ischemic tissue at sites of angiogenesis in vivo, the model of endothelial regeneration has been extended. The majority of clinical trials on human cell therapy for ischemic vascular disease are based on cell surface antigen expression of CD34 or VEGFR2 to identify endothelial progenitor cells.A precise characterization of the angiogenic properties of different subsets of endothelial regenerating cells and their course of action to gain sufficient long-term regeneration of the injured vessel is a necessary precondition before clinical trials of human cell therapy become a routine reality. PMID: 20842474 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Cancer-Related Epigenome Changes Associated with Reprogramming to Induced Pluripotent Stem Cells. Cancer Res. 2010 Sep 14; Authors: Ohm JE, Mali P, Van Neste L, Berman DM, Liang L, Pandiyan K, Briggs KJ, Zhang W, Argani P, Simons B, Yu W, Matsui W, Van Criekinge W, Rassool FV, Zambidis E, Schuebel KE, Cope L, Yen J, Mohammad HP, Cheng L, Baylin SB The ability to induce pluripotent stem cells from committed, somatic human cells provides tremendous potential for regenerative medicine. However, there is a defined neoplastic potential inherent to such reprogramming that must be understood and may provide a model for understanding key events in tumorigenesis. Using genome-wide assays, we identify cancer-related epigenetic abnormalities that arise early during reprogramming and persist in induced pluripotent stem cell (iPS) clones. These include hundreds of abnormal gene silencing events, patterns of aberrant responses to epigenetic-modifying drugs resembling those for cancer cells, and presence in iPS and partially reprogrammed cells of cancer-specific gene promoter DNA methylation alterations. Our findings suggest that by studying the process of induced reprogramming, we may gain significant insight into the origins of epigenetic gene silencing associated with human tumorigenesis, and add to means of assessing iPS for safety. Cancer Res; 70(19); OF1-12. ©2010 AACR. PMID: 20841480 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Identification of preferential target sites for human DNA methyltransferases. Nucleic Acids Res. 2010 Sep 13; Authors: Choi SH, Heo K, Byun HM, An W, Lu W, Yang AS DNA methyltransferases (DNMTs) play an important role in establishing and maintaining DNA methylation. Aberrant expression of DNMTs and their isoforms has been found in many types of cancer, and their contribution to aberrant DNA methylation has been proposed. Here, we generated HEK 293T cells stably transfected with each of 13 different DNMTs (DNMT1, two DNMT3A isoforms, nine DNMT3B isoforms and DNMT3L) and assessed the DNA methylation changes induced by each DNMT. We obtained DNA methylation profiles of DNA repetitive elements and 1505 CpG sites from 808 cancer-related genes. We found that DNMTs have specific and overlapping target sites and their DNA methylation target profiles are a reflection of the DNMT domains. By examining H3K4me3 and H3K27me3 modifications in the 808 gene promoter regions using promoter ChIP-on-chip analysis, we found that specific de novo DNA methylation target sites of DNMT3A1 are associated with H3K4me3 modification that are transcriptionally active, whereas the specific target sites of DNMT3B1 are associated with H3K27me3 modification that are transcriptionally inactive. Our data suggest that different DNMT domains are responsible for targeting DNA methylation to specific regions of the genome, and this targeting might be associated with histone modifications. PMID: 20841325 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The role of surgical debridement in healing of diabetic foot ulcers. Wound Repair Regen. 2010 Sep;18(5):433-438 Authors: Lebrun E, Tomic-Canic M, Kirsner RS An estimated 15% of patients with diabetes mellitus will develop a foot ulcer during their lifetime. Debridement is included in multiple guidelines and algorithms for the care of patients with diabetic neuropathic foot ulcers, and it has long been considered an essential step in the protocol for treating diabetic foot ulcers. In addition to altering the environment of the chronic wound, debridement is a technique aimed at removing nonviable and necrotic tissue, thought to be detrimental to healing. This is accomplished by removing abnormal wound bed and wound edge tissue, such as hyperkeratotic epidermis (callus) and necrotic dermal tissue, foreign debris, and bacteria elements known to have an inhibitory effect on wound healing. While the rationale for surgical debridement seems logical, the evidence for its role in enhancing healing is deficient. In this paper, we systematically review five published clinical trials, which met the criteria and investigated surgical debridement of diabetic foot ulcers to enhance healing. Most existing studies are not randomized clinical trials optimized to test the relationship between debridement of diabetic foot ulcers and wound healing. Therefore, a focused, well-designed study is needed to elucidate the effect of surgical debridement on the healing status of chronic wounds. PMID: 20840517 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Liver-assist device with a microfluidics-based vascular bed in an animal model. Ann Surg. 2010 Aug;252(2):351-7 Authors: Hsu WM, Carraro A, Kulig KM, Miller ML, Kaazempur-Mofrad M, Weinberg E, Entabi F, Albadawi H, Watkins MT, Borenstein JT, Vacanti JP, Neville C OBJECTIVE: This study evaluates a novel liver-assist device platform with a microfluidics-modeled vascular network in a femoral arteriovenous shunt in rats. SUMMARY OF BACKGROUND DATA: Liver-assist devices in clinical trials that use pumps to force separated plasma through packed beds of parenchymal cells exhibited significant necrosis with a negative impact on function. METHODS: Microelectromechanical systems technology was used to design and fabricate a liver-assist device with a vascular network that supports a hepatic parenchymal compartment through a nanoporous membrane. Sixteen devices with rat primary hepatocytes and 12 with human HepG2/C3A cells were tested in athymic rats in a femoral arteriovenous shunt model. Several parenchymal tube configurations were evaluated for pressure profile and cell survival. The blood flow pattern and perfusion status of the devices was examined by laser Doppler scanning. Cell viability and serum protein secretion functions were assessed. RESULTS: Femoral arteriovenous shunt was successfully established in all animals. Blood flow was homogeneous through the vascular bed and replicated native flow patterns. Survival of seeded liver cells was highly dependent on parenchymal chamber pressures. The tube configuration that generated the lowest pressure supported excellent cell survival and function. CONCLUSIONS: This device is the first to incorporate a microfluidics network in the systemic circulatory system. The microvascular network supported viability and function of liver cells in a short-term ex vivo model. Parenchymal chamber pressure generated in an arteriovenous shunt model is a critical parameter that affects viability and must be considered in future designs. The microfluidics-based vascular network is a promising platform for generating a large-scale medical device capable of augmenting liver function in a clinical setting. PMID: 20647924 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Substrate elasticity regulates skeletal muscle stem cell self-renewal in culture. Science. 2010 Aug 27;329(5995):1078-81 Authors: Gilbert PM, Havenstrite KL, Magnusson KE, Sacco A, Leonardi NA, Kraft P, Nguyen NK, Thrun S, Lutolf MP, Blau HM Stem cells that naturally reside in adult tissues, such as muscle stem cells (MuSCs), exhibit robust regenerative capacity in vivo that is rapidly lost in culture. Using a bioengineered substrate to recapitulate key biophysical and biochemical niche features in conjunction with a highly automated single-cell tracking algorithm, we show that substrate elasticity is a potent regulator of MuSC fate in culture. Unlike MuSCs on rigid plastic dishes (approximately 10(6) kilopascals), MuSCs cultured on soft hydrogel substrates that mimic the elasticity of muscle (12 kilopascals) self-renew in vitro and contribute extensively to muscle regeneration when subsequently transplanted into mice and assayed histologically and quantitatively by noninvasive bioluminescence imaging. Our studies provide novel evidence that by recapitulating physiological tissue rigidity, propagation of adult muscle stem cells is possible, enabling future cell-based therapies for muscle-wasting diseases. PMID: 20647425 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Discrepancies between metabolic activity and DNA content as tool to assess cell proliferation in cancer research. J Cell Mol Med. 2010 Apr;14(4):1003-13 Authors: Quent VM, Loessner D, Friis T, Reichert JC, Hutmacher DW Cell proliferation is a critical and frequently studied feature of molecular biology in cancer research. Therefore, various assays are available using different strategies to measure cell proliferation. Metabolic assays such as AlamarBlue, water-soluble tetrazolium salt and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide, which were originally developed to determine cell toxicity, are used to assess cell numbers. Additionally, proliferative activity can be determined by quantification of DNA content using fluorophores such as CyQuant and PicoGreen. Referring to data published in high ranking cancer journals, these assays were applied in 945 publications over the past 14 years to examine the proliferative behaviour of diverse cell types. In these studies, however, mainly metabolic assays were used to quantify changes in cell growth yet these assays may not accurately reflect cellular proliferation rates due to a miscorrelation of metabolic activity and cell number. Testing this hypothesis, we compared the metabolic activity of different cell types, human cancer cells and primary cells, over a time period of 4 days using AlamarBlue and the fluorometric assays CyQuant and PicoGreen to determine their DNA content. Our results show certain discrepancies in terms of over-estimation of cell proliferation with respect to the metabolic assay in comparison to DNA binding fluorophores. PMID: 20082656 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Electrospun Functionalized Polyaniline Copolymer-Based Nanofibers with Potential Application in Tissue Engineering. Macromol Biosci. 2010 Sep 14; Authors: Gizdavic-Nikolaidis M, Ray S, Bennett JN, Easteal AJ, Cooney RP Nanofibrous blends of HCl-doped poly(aniline-co-3-aminobenzoic acid) (3ABAPANI) copolymer and poly(lactic acid) (PLA) were fabricated by electrospinning solutions of the polymers, in varying relative proportions, in dimethyl sulfoxide/tetrahydrofuran mixture. The morphology, mechanical and electrical properties of the nanofibers were characterized and an assessment of their bioactivity performed. To assess cell morphology and biocompatibility, pure PLA and 3ABAPANI-PLA nanofibrous mats were deposited in the form of three-dimensional networks with a high degree of connectivity, on glass substrates, and their ability to promote proliferation of COS-1 fibroblast cells was determined. The nanofibrous electrospun 3ABAPANI-PLA blends gave enhanced cell growth, potent antimicrobial capability against Staphylococcus aureus and electrical conductivity. This new class of nanofibrous blends can potentially be employed as tissue engineering scaffolds, and in particular have showed promise as the basis of a new generation of functional wound dressings that may eliminate deficiencies of currently available antimicrobial dressings. PMID: 20842683 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Endothelial cell behaviour within a microfluidic mimic of the flow channels of a modular tissue engineered construct. Biomed Microdevices. 2010 Sep 15; Authors: Khan OF, Sefton MV To study the effect of disturbed flow patterns on endothelial cells, the channels found within a modular tissue engineering construct were reproduced in a microfluidic chip and lined with endothelial cells whose resulting phenotype under flow was assessed using confocal microscopy. Modular tissue engineered constructs formed by the random packing of sub-millimetre, cylindrically shaped, endothelial cell-covered modules into a larger container creates interconnected channels that permit the flow of fluids such as blood. Due to the random packing, the flow path is tortuous and has the potential to create disturbed flow, resulting in an activated endothelium. At an average shear stress of 2.8 dyn cm( -2), endothelial cells within channels of varying geometries showed higher amounts of activation, as evidenced by an increase in ICAM-1 and VCAM-1 levels with respect to static controls. VE-cadherin expression also increased, however, it appeared discontinuous around the perimeter of the cells. An increase in flow (15.6 dyn cm( -2)) was sufficient to reduce ICAM-1 and VCAM-1 expression to a level below that of static controls for many disturbed flow-prone channels that contained branches, curves, expansions and contractions. VE-cadherin expression was also reduced and became discontinuous in all channels, possibly due to paracrine signaling. Other than showing a mild correlation to VE-cadherin, which may be linked through a cAMP-initiated pathway, KLF2 was found to be largely independent of shear stress for this system. To gauge the adhesiveness of the endothelium to leukocytes, THP-1 cells were introduced into flow-conditioned channels and their attachment measured. Relative to static controls, THP-1 adhesion was reduced in straight and bifurcating channels. However, even in the presence of flow, areas where multiple channels converged were found to be the most prone to THP-1 attachment. The microfluidic system enabled a full analysis of the effect of the tortuous flow expected in a modular construct on endothelial cell phenotype. PMID: 20842530 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Posterior lumbar interbody fusion using non resorbable poly-ether-ether-ketone versus resorbable poly-L: -lactide-co-D: ,L: -lactide fusion devices. Clinical outcome at a minimum of 2-year follow-up. Eur Spine J. 2010 Sep 15; Authors: Jiya TU, Smit T, van Royen BJ, Mullender M Previous papers on resorbable poly-L: -lactide-co-D: ,L: -lactide (PLDLLA) cages in spinal fusion have failed to report adequately on patient-centred clinical outcome measures. Also comparison of PLDLLA cage with a traditionally applicable counterpart has not been previously reported. This is the first randomized prospective study that assesses clinical outcome of PLDLLA cage compared with a poly-ether-ether-ketone (PEEK) implant. Twenty-six patients were randomly assigned to undergo instrumented posterior lumbar interbody fusion (PLIF) whereby either a PEEK cage or a PLDLLA cage was implanted. Clinical outcome based on visual analogue scale scores for leg pain and back pain, as well as Oswestry Disability Index (ODI) and SF-36 questionnaires were documented and analysed. When compared with preoperative values, all clinical parameters have significantly improved in the PEEK group at 2 years after surgery with the exception of SF-36 general health, SF-36 mental health and SF-36 role emotional scores. No clinical parameter showed significant improvement at 2 years after surgery compared with preoperative values in the PLDLLA patient group. Only six patients (50%) in the PLDLLA group showed improvement in the VAS scores for leg and back pain as well as the ODI, as opposed to 10 patients (71%) in the PEEK group. One-third of the patients in the PLDLLA group actually reported worsening of their pain scores and ODI. Three cases of mild to moderate osteolysis were seen in the PLDLLA group. Following up on our preliminary report, these 2-year results confirm the superiority of the PEEK implant to the resorbable PLDLLA implant in aiding spinal fusion and alleviating symptoms following PLIF in patients with degenerative spondylolisthesis associated with either canal stenosis or foramen stenosis or both and emanating from a single lumbar segment. PMID: 20842388 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Tissue engineering for treatment of vocal fold scar. Curr Opin Otolaryngol Head Neck Surg. 2010 Sep 14; Authors: Long JL PURPOSE OF REVIEW: Creating a neovocal fold or lamina propria by tissue engineering is a potential scheme for treating severe vocal fold scar. Although still investigational, multiple approaches have recently been described in tissue culture or animal models. RECENT FINDINGS: Proposed cell types for vocal fold application have been native vocal fold fibroblasts, autologous fibroblasts from nonlaryngeal tissues, and adult-derived stem cells. Scaffolds of interest include decellularized matrix, biological polymers, and synthetic or chemically modified biopolymers. Chemical, mechanical, and spatial signals have been applied, such as hepatocyte growth factor, cyclic stretch, and air interface. Cells, matrix, and signals are combined in an effort to replicate normal vocal fold tissue as closely as possible. Each of these components of vocal fold tissue engineering is discussed here. SUMMARY: Multiple tissue engineering approaches hold promise for reproducing functional vocal fold tissue. Scar prevention techniques have been the most successful. Modifying existing scar is more difficult and may necessitate complete scar excision and replacement with a three-dimensional neotissue. Functional assessment in vivo is essential to the ongoing evaluation of techniques. PMID: 20842033 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Text Mining approaches for Automated Literature Knowledge Extraction and Representation. Stud Health Technol Inform. 2010;160:954-958 Authors: Nuzzo A, Mulas F, Gabetta M, Arbustini E, Zupan B, Larizza C, Bellazzi R Due to the overwhelming volume of published scientific papers, information tools for automated literature analysis are essential to support current biomedical research. We have developed a knowledge extraction tool to help researcher in discovering useful information which can support their reasoning process. The tool is composed of a search engine based on Text Mining and Natural Language Processing techniques, and an analysis module which process the search results in order to build annotation similarity networks. We tested our approach on the available knowledge about the genetic mechanism of cardiac diseases, where the target is to find both known and possible hypothetical relations between specific candidate genes and the trait of interest. We show that the system i) is able to effectively retrieve medical concepts and genes and ii) plays a relevant role assisting researchers in the formulation and evaluation of novel literature-based hypotheses. PMID: 20841825 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Microstructure and cytocompatibility of collagen matrices for urological tissue engineering. BJU Int. 2010 Sep 14; Authors: Montzka K, Läufer T, Becker C, Grosse J, Heidenreich A OBJECTIVE: •  To analyse the in vitro cytocompatibility of several engineered collagen-based biomaterials for tissue engineering of the urinary tract. •  Tissue-engineered implants for the reconstruction of the urinary tract are of major interest for urological researchers as well as clinicians. Although several materials have been investigated, the ideal replacement has still to be identified. MATERIALS AND METHODS: •  Several collagen matrices were tested. •  Electron microscopy was used to visualize the microstructure of the tested matrices. •  Examination of cell attachment and growth of primary porcine urothelial and smooth muscle cells were performed and cell phenotypes were analysed using immunohistochemical stains. •  Urea permeability was investigated using Ussing chamber experiments. RESULTS: •  The best cytocompatibility for both urinary tract-specific cell types was obtained with OptiMaix® (Matricel GmbH, Herzogenrath, Germany) materials. •  Cell-specific phenotypes were maintained during culture as shown by immunohistochemical staining. •  Furthermore, simultaneous cultivation of both cell types for 7 and 14 days significantly reduced urea permeability. CONCLUSIONS: •  These results show the potential of OptiMaix materials in tissue engineering approaches of urinary tract tissues. PMID: 20840325 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Photo-Cross-Linkable Thermoresponsive Star Polymers Designed for Control of Cell-Surface Interactions. Biomacromolecules. 2010 Sep 14; Authors: Park S, Cho HY, Yoon JA, Kwak Y, Srinivasan A, Hollinger JO, Paik HJ, Matyjaszewski K Star polymers with thermoresponsive arms, consisting of 2-(2-methoxyethoxy)ethyl methacrylate (MEO(2)MA) and oligo(ethylene glycol) methacrylate with ∼4 ethylene oxide units (OEOMA(300), M(n) = 300), were synthesized via atom transfer radical polymerization (ATRP). 25% of the arms contained benzophenone chain-end functionality at the star periphery. A mixture of linear poly(MEO(2)MA-co-OEOMA(300))-Br macroinitiators without and with benzophenone end-group macroinitiators were (MI and Bzp-MI, respectively) cross-linked with ethylene glycol dimethacrylate to form star polymers. Formation of star polymers was monitored by GPC, and the presence of benzophenone functionality in the stars was confirmed by (1)H NMR. The UV-vis spectroscopy revealed that the star polymers exhibit the low critical solution temperature (LCST) at 27 °C, slightly lower than LCST of either MI or Bzp-MI. Commercially available tissue culture grade polystyrene surface was modified by depositing a thin film of functionalized stars and UV cross-linking (λ = 365 nm). The star polymers covalently attached onto surfaces allowed a control of cell shrinkage and attachment in response to temperature changes. PMID: 20839794 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Finite element analysis of a personalized femoral scaffold with designed microarchitecture. Proc Inst Mech Eng H. 2010;224(7):877-89 Authors: Pandithevan P, Kumar GS Tissue engineering scaffolds with intricate and controlled internal structure can be realized using computer-aided design (CAD) and layer manufacturing (LM) techniques. Design and manufacturing of scaffolds for load-bearing bone sites should consider appropriate biocompatibile materials with interconnected porosity, surface properties, and sufficient mechanical properties that match the surrounding bone, in order to provide adequate support, and to mimic the physiological stress-strain state so as to stimulate new tissue growth. The authors have previously published methods for estimating subject- and site-specific bone modulus using computed tomography (CT) data, CAD, and process planning for LM of controlled porous scaffolds. This study evaluates the mechanical performance of the designed porous hydroxyapite scaffolds in load-bearing sites using a finite element (FE) approach. A subject-specific FE analysis using femoral, defect site geometry and anisotropic material assignment based on CT data is employed. Mechanical behaviour of the femur with scaffold in stance-phase gait loading, which has been shown experimentally to produce clinically relevant results, is analysed. The comparison of results with simulation of healthy femur shows an overall correspondence in stress and strain state which will provide optimized mechanical properties for avoiding stress shielding, and adequate strength to avoid failure risk and for active bone tissue regeneration. PMID: 20839655 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | [Experimental study on biocompatibility of vascular tissue engineering scaffold of epsilon-caprolactone and L-lactide] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2010 Aug;24(8):988-92 Authors: Li C, Dong J, Gu Y, Ye L, Chen X, Bian C, Feng Z, Wang Z OBJECTIVE: To explore the method of preparing the electrospinning of synthesized triblock copolymers of epsilon-caprolactone and L-lactide (PCLA) for the biodegradable vascular tissue engineering scaffold and to investigate its biocompatibility in vitro. METHODS: The biodegradable vascular tissue engineering scaffold was made by the electrospinning process of PCLA. A series of biocompatibility tests were performed. Cytotoxicity test: the L929 cells were cultured in 96-well flat-bottomed plates with extraction media of PCLA in the experimental group and with the complete DMEM in control group, and MTT method was used to detect absorbance (A) value (570 nm) every day after culture. Acute general toxicity test: the extraction media and saline were injected into the mice's abdominal cavity of experimental and control groups, respectively, and the toxicity effects on the mice were observed within 72 hours. Hemolysis test: anticoagulated blood of rabbit was added into the extracting solution, saline, and distilled water in 3 groups, and MTT method was used to detect A value in 3 groups. Cell attachment test: the L929 cells were seeded on the PCLA material and scanning electron microscope (SEM) observation was performed 4 hours and 3 days after culture. Subcutaneous implantation test: the PCLA material was implanted subcutaneously in rats and the histology observation was performed at 1 and 8 weeks. RESULTS: Scaffolds had the characteristics of white color, uniform texture, good elasticity, and tenacity. The SEM showed that the PCLA ultrafine fibers had a smooth surface and proper porosity; the fiber diameter was 1-5 microm and the pore diameter was in the range of 10-30 microm. MTT detection suggested that there was no significant difference in A value among 3 groups every day after culturing (P > 0.05). The mice in 2 groups were in good physical condition and had no respiratory depression, paralysis, convulsion, and death. The hemolysis rate was 1.18% and was lower than the normal level (5%). The SEM showed a large number of attached L929 cells were visible on the surface of the PCLA material at 4 hours after implantation and the cells grew well after 3 days. The PCLA material was infiltrated by the inflammatory cells after 1 week. The inflammatory cells reduced significantly and the fiber began abruption after 8 weeks. CONCLUSION: The biodegradable vascular tissue engineering scaffold material made by the electrospinning process of PCLA has good microstructure without cytotoxicity and has good biocompatibility. It can be used as an ideal scaffold for vascular tissue engineering. PMID: 20839451 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Collagen-PCL Sheath-Core Bicomponent Electrospun Scaffolds Increase Osteogenic Differentiation and Calcium Accretion of Human Adipose-Derived Stem Cells. J Biomater Sci Polym Ed. 2010 Sep 10; Authors: Haslauer CM, Moghe AK, Osborne JA, Gupta BS, Loboa EG Human adipose-derived stem cells (hASCs) are an abundant cell source capable of osteogenic differentiation, and have been investigated as an autologous stem cell source for bone tissue engineering applications. The objective of this study was to determine if the addition of a type-I collagen sheath to the surface of poly(ɛ-caprolactone) (PCL) nanofibers would enhance viability, proliferation and osteogenesis of hASCs. This is the first study to examine the differentiation behavior of hASCs on collagen-PCL sheath-core bicomponent nanofiber scaffolds developed using a co-axial electrospinning technique. The use of a sheath-core configuration ensured a uniform coating of collagen on the PCL nanofibers. PCL nanofiber scaffolds prepared using a conventional electrospinning technique served as controls. hASCs were seeded at a density of 20 000 cells/cm(2) on 1 cm(2) electrospun nanofiber (pure PCL or collagen-PCL sheath-core) sheets. Confocal microscopy and hASC proliferation data confirmed the presence of viable cells after 2 weeks in culture on all scaffolds. Greater cell spreading occurred on bicomponent collagen-PCL scaffolds at earlier time points. hASCs were osteogenically differentiated by addition of soluble osteogenic inductive factors. Calcium quantification indicated cell-mediated calcium accretion was approx. 5-times higher on bicomponent collagen-PCL sheath-core scaffolds compared to PCL controls, indicating collagen-PCL bicomponent scaffolds promoted greater hASC osteogenesis after two weeks of culture in osteogenic medium. This is the first study to examine the effects of collagen-PCL sheath-core composite nanofibers on hASC viability, proliferation and osteogenesis. The sheath-core composite fibers significantly increased calcium accretion of hASCs, indicating that collagen-PCL sheath-core bicomponent structures have potential for bone tissue engineering applications using hASCs. PMID: 20836922 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Sequential fluorescent labeling observation of maxillary sinus augmentation by a tissue-engineered bone complex in canine model. Int J Oral Sci. 2009 Mar;1(1):39-46 Authors: Jiang XQ, Wang SY, Zhao J, Zhang XL, Zhang ZY AIM: To evaluate the effects of maxillary sinus floor elevation by a tissue-engineered bone complex of beta-tricalcium phosphate (beta-TCP) and autologous osteoblasts in dogs. METHODOLOGY: Autologous osteoblasts from adult Beagle dogs were cultured in vitro. They were further combined with beta-TCP to construct the tissue-engineered bone complex. 12 cases of maxillary sinus floor elevation surgery were made bilaterally in 6 animals and randomly repaired with the following 3 groups of materials: Group A (osteoblasts/beta-TCP); Group B (beta-TCP); Group C (autogenous bone) (n=4 per group). A polychrome sequential fluorescent labeling was performed post-operatively and the animals were sacrificed 24 weeks after operation for histological observation. RESULTS: Our results showed that autologous osteoblasts were successfully expanded and the osteoblastic phenol-types were confirmed by ALP and Alizarin red staining. The cells could attach and proliferate well on the surface of the beta-TCP scaffold. The fluorescent and histological observation showed that the tissue-engineered bone complex had an earlier mineralization and more bone formation inside the scaffold than beta-TCP along or even autologous bone. It had also maximally maintained the elevated sinus height than both control groups. CONCLUSION: Porous beta-TCP has served as a good scaffold for autologous osteoblasts seeding. The tissue-engineered bone complex with beta-TCP and autologous osteoblasts might be a better alternative to autologous bone for the clinical edentulous maxillary sinus augmentation. PMID: 20690503 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Multilineage differentiation of dental pulp stem cells from green fluorescent protein transgenic mice. Int J Oral Sci. 2010 Mar;2(1):21-7 Authors: Grottkau BE, Purudappa PP, Lin YF AIM: The aim of this study was to confirm the multilineage differentiation ability of dental pulp stem cells (DPSCs) from green fluorescent protein (GFP) transgenic mice. The expression of GFP in DPSCs was also observed during differentiation. METHODOLOGY: DPSCs were harvested from the dental pulp tissue of transgenic nude mice, and then transferred to osteogenic, adipogenic, and chondrogenic media. The morphological characterization of induced cells was observed by microscopy and histological staining. The expression of marker genes was measured by RT-PCR. RESULTS: The endogenous GFP and multilineage potential of transgenic DPSCs had no influence on each other. Moreover, the results of fluorescence microscopic imaging suggest that there was no significant decline of GFP expression during DPSCs differentiation. CONCLUSION: As the population of GFP labeled DPSCs can be easily identified, this will be a promising method for tracking DPSCs in vivo. PMID: 20690415 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | DAPT enhances the apoptosis of human tongue carcinoma cells. Int J Oral Sci. 2009 Jun;1(2):81-9 Authors: Grottkau BE, Chen XR, Friedrich CC, Yang XM, Jing W, Wu Y, Cai XX, Liu YR, Huang YD, Lin YF AIM: To investigate the effect of DAPT (gamma-secretase inhibitor) on the growth of human tongue carcinoma cells and to determine the molecular mechanism to enable the potential application of DAPT to the treatment of tongue carcinoma. METHODOLOGY: Human tongue carcinoma Tca8113 cells were cultured with DAPT. Cell growth was determined using Indigotic Reduction method. The cell cycle and apoptosis were analyzed by flow cytometry. Real-time PCR and Immuno-Fluorescence (IF) were employed to determine the intracellular expression levels. RESULTS: DAPT inhibited the growth of human tongue carcinoma Tca8113 cells by inducing G0-G1 cell cycle arrest and apoptosis. The mRNA levels of Hairy/Enhancer of Split-1 (Hes-1), a target of Notch activation, were reduced by DAPT in a dose-dependent manner. Coincident with this observation, DAPT induced a dose-dependent promotion of constitutive Caspase-3 in Tca8113 cells. CONCLUSION: DAPT may have a therapeutic value for human tongue carcinoma. Moreover, the effects of DAPT in tumor inhibition may arise partly via the modulation of Notch-1 and Caspase-3. PMID: 20687300 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Nanobiotechnology--quo vadis? Curr Opin Microbiol. 2010 Jun;13(3):327-34 Authors: Koopmans RJ, Aggeli A PMID: 20149720 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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