|  |  |  | | | | | pubmed: "regenerative medici... | | | | | | | | | | | | | | | | | | | Characterisation of the human nucleus pulposus cell phenotype and evaluation of novel marker gene expression to define adult stem cell differentiation. Arthritis Rheum. 2010 Aug 18; Authors: Minogue BM, Richardson SM, Zeef LA, Freemont AJ, Hoyland JA OBJECTIVE.: Development of stem cell therapies for regeneration of the nucleus pulposus (NP) are hindered by the lack of specific markers to distinguish NP cells from articular chondrocytes (AC cells). This study details, for the first time, gene expression profiling to identify the human NP phenotype and assesses whether the identified markers can distinguish mesenchymal stem cell (MSC) differentiation to a correct NP cell phenotype. METHODS.: Affymetrix Microarrays were conducted on human NP and AC cells and differential expression levels for several positive (NP) and negative (AC) marker genes validated by qRT-PCR. Novel marker gene and protein expression was also assessed in human bone marrow-derived MSCs (BM-MSCs) and adipose-derived MSCs (ASCs) following differentiation in type I collagen gels. RESULTS.: Analysis identified 12 NP positive and 36 negative marker genes differentially expressed >/=20 fold and for a subset (NP positive genes PAX1, FOXF1, HBB, CA12 and OVOS2; AC genes GDF10, CYTL1, IBSP and FBLN1) differential expression was confirmed by qRT-PCR. Differentiated BM-MSCs and ASCs demonstrated significant increases in the novel NP markers PAX1 and FOXF1. ASCs lacked expression of the AC markers IBSP and FBLN1, whereas BM-MSCs lacked expression of the AC marker IBSP but expressed FBLN1. CONCLUSION.: This study has identified the phenotypic profile of human NP cells. Importantly these markers can be used to determine the in vitro differentiation of MSCs to an NP-like rather than an AC-like phenotype. Interestingly, these results suggest that ASCs may be a more appropriate cell type than BM-MSCs for IVD tissue engineering. PMID: 20722018 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Photochemically crosslinked matrices of gelatin and fibrinogen promote rapid cell proliferation. J Tissue Eng Regen Med. 2010 Aug 17; Authors: Sando L, Danon S, Brownlee AG, McCulloch RJ, Ramshaw JA, Elvin CM, Werkmeister JA Here we report the use of a facile photochemical crosslinking method to fabricate stable polymer matrices from unmodified gelatin and fibrinogen. Gels were produced by covalent crosslinking of the proteins in a rapid photo-oxidative process, catalysed by a ruthenium metal complex and irradiation with visible light. For generation of macroporous, spongy matrices, the proteins and crosslinking reagents were mixed with catalase and hydrogen peroxide to achieve a foaming reaction, producing a stable, foamed matrix that was subsequently photo-crosslinked. C2C12 cells were either seeded onto the matrices after photo-curing or embedded in the protein matrix prior to foaming and crosslinking. Cells seeded onto scaffolds post-curing showed high cell viability and rapid proliferation in vitro. For cells embedded in the matrix prior to crosslinking there was some loss of initial viability, but surviving cells were able to proliferate after a period of in vitro cultivation. The matrices were shown to be biocompatible when implanted into nude mice, with evidence of proliferation and differentiation of cells seeded into the scaffolds. The results are promising for further development of tissue-engineering scaffolds based on this ruthenium-catalysed photo-crosslinking method. Copyright (c) 2010 John Wiley & Sons, Ltd. PMID: 20721871 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Effect of cyclic three-dimensional strain on cell proliferation and collagen synthesis of fibroblast-seeded chitosan-hyaluronan hybrid polymer fiber. J Orthop Sci. 2010 Jul;15(4):569-77 Authors: Sawaguchi N, Majima T, Funakoshi T, Shimode K, Harada K, Minami A, Nishimura S BACKGROUND: Tissue engineering techniques using biodegradable three-dimensional (3D) scaffolds with cultured cells offer more potential alternatives for the treatment of severe ligament and tendon injuries. In tissue engineering, one of the crucial roles of 3D scaffolds is to provide a temporary template with the biomechanical characteristics of the native extracellular matrix (ECM) until the regenerated tissue matures. The purpose of the present study was to assess the effect of various cyclic mechanical stresses on cell proliferation and ECM production in a 3D scaffold made from chitosan and hyaluronan for ligament and tendon tissue engineering. METHODS: Three-dimensional scaffolds seeded with rabbit patella tendon fibroblasts were attached to a bioreactor under various conditions: static group, no strain; stretch group, tensile strain; rotational group, rotational strain; combined group, rotational and tensile strain. In the Static group, 3 weeks of stationary culture was performed. In the remaining three groups, a loading regimen of 0.5 Hz for 18 h and then 6 h rest was carried out for 2 weeks after 1 week of static culture. The DNA content was determined to quantify cell proliferation. Real-time reverse transcription polymerase chain reaction analysis was performed to assess the mRNA levels of the ECM products. RESULTS: DNA content of the combined group was significantly higher than that of the static and stretch groups, and that of the rotational group was significant higher than that of the static and stretch groups at 21 days after cultivation. The mRNA level of types I and III collagen and fibromodulin in the combined group was significantly higher than that in the other three groups. The amount of collagen synthesis in the combined group was higher than that in the static group, but the difference was not significant. CONCLUSIONS: Multidimensional cyclic mechanical strain to mimic the physiological condition in vivo has the potential to improve or accelerate tissue regeneration in ligament and tendon tissue engineering using 3D scaffolds in vitro. PMID: 20721727 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Macrophage Response to UHMWPE Submitted to Accelerated Ageing in Hydrogen Peroxide. Open Biomed Eng J. 2010;4:107-12 Authors: Rocha MF, Mansur AA, Martins CP, Barbosa-Stancioli EF, Mansur HS Ultra-high molecular weight polyethylene (UHMWPE) has been the most commonly used bearing material in total joint arthroplasty. Wear and oxidation fatigue resistance of UHMWPE are regarded as two important properties to extend the longevity of knee prostheses. The present study investigated the accelerated ageing of UHMWPE in hydrogen peroxide highly oxidative chemical environment. The sliced samples of UHMWPE were oxidized in a hydrogen peroxide solution for 120 days with their total level of oxidation (Iox) characterized by Fourier Transformed Infrared Spectroscopy (FTIR). The potential inflammatory response, cell viability and biocompatibility of such oxidized UHMWPE systems were assessed by a novel biological in vitro assay based on the secretion of nitric oxide (NO) by activated murine macrophages with gamma interferon (IFN-gamma) cytokine and lipopolysaccharide (LPS). Furthermore, macrophage morphologies in contact with UHMWPE oxidized surfaces were analyzed by cell spreading-adhesion procedure using scanning electron microscopy (SEM). The results have given significant evidence that the longer the period of accelerated aging of UHMWPE the higher was the macrophage inflammatory equivalent response based on NO secretion analysis. PMID: 20721321 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Intravascular route is not superior to an intraperitoneal route for in utero transplantation of human hematopoietic stem cells and engraftment in sheep. Transplantation. 2010 Aug 27;90(4):462-3 Authors: Tanaka Y, Masuda S, Abe T, Hayashi S, Kitano Y, Nagao Y, Hanazono Y PMID: 20720481 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Multivalent integrin-specific ligands enhance tissue healing and biomaterial integration. Sci Transl Med. 2010 Aug 18;2(45):45ra60 Authors: Petrie TA, Raynor JE, Dumbauld DW, Lee TT, Jagtap S, Templeman KL, Collard DM, GarcÃa AJ Engineered biointerfaces covered with biomimetic motifs, including short bioadhesive ligands, are a promising material-based strategy for tissue repair in regenerative medicine. Potentially useful coating molecules are ligands for the integrins, major extracellular matrix receptors that require both ligand binding and nanoscale clustering for maximal signaling efficiency. We prepared coatings consisting of well-defined multimer constructs with a precise number of recombinant fragments of fibronectin (monomer, dimer, tetramer, and pentamer) to assess how nanoscale ligand clustering affects integrin binding, stem cell responses, tissue healing, and biomaterial integration. Clinical-grade titanium was grafted with polymer brushes that presented monomers, dimers, trimers, or pentamers of the alpha(5)beta(1) integrin-specific fibronectin III (7 to 10) domain (FNIII(7-10)). Coatings consisting of trimers and pentamers enhanced integrin-mediated adhesion in vitro, osteogenic signaling, and differentiation in human mesenchymal stem cells more than did surfaces presenting monomers and dimers. Furthermore, ligand clustering promoted bone formation and functional integration of the implant into bone in rat tibiae. This study establishes that a material-based strategy in which implants are coated with clustered bioadhesive ligands can promote robust implant-tissue integration. PMID: 20720217 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | The Polycystic Ovary Post-Rotterdam: A Common, Age-Dependent Finding in Ovulatory Women without Metabolic Significance. J Clin Endocrinol Metab. 2010 Aug 18; Authors: Johnstone EB, Rosen MP, Neril R, Trevithick D, Sternfeld B, Murphy R, Addauan-Andersen C, McConnell D, Pera RR, Cedars MI Introduction: The age-specific prevalence of polycystic ovaries (PCO), as defined by the Rotterdam criteria, among normal ovulatory women, has not yet been reported. It is also uncertain whether these women differ from their peers in the hormonal or metabolic profile. Methods: A total of 262 ovulatory Caucasian women aged 25-45 yr, enrolled in a community-based ovarian aging study (OVA), underwent transvaginal ultrasound assessment of ovarian volume and antral follicle count (AFC) in the early follicular phase and were categorized as to whether they met the Rotterdam definition of PCO by AFC (>/=12 in one ovary) and/or by volume (>10 cm(3) for one ovary). The effect of age on prevalence of PCO was assessed. Serum hormones and metabolic measures were compared between women meeting each element of the Rotterdam criterion and those without PCO using age-adjusted linear regressions. Results: The prevalence of PCO by AFC was 32% and decreased with age. Those with PCO by AFC had lower FSH; higher anti-Mullerian hormone, estrone, dehydroepiandrostenedione sulfate, and free androgen index; and slightly higher total testosterone than those without PCO. However, slightly higher body mass index and waist circumference were the only metabolic differences. Women with PCO by volume had higher anti-Mullerian hormone and free androgen index but did not differ in any other hormonal or metabolic parameter. Discussion: PCO is a common, age-dependent finding among ovulatory women. These women lack the metabolic abnormalities seen in PCO syndrome. Isolated PCO in an ovulatory woman is not an indication for metabolic evaluation. PMID: 20719841 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Growth factor delivery-based tissue engineering: general approaches and a review of recent developments. J R Soc Interface. 2010 Aug 18; Authors: Lee K, Silva EA, Mooney DJ The identification and production of recombinant morphogens and growth factors that play key roles in tissue regeneration have generated much enthusiasm and numerous clinical trials, but the results of many of these trials have been largely disappointing. Interestingly, the trials that have shown benefit all contain a common denominator, the presence of a material carrier, suggesting strongly that spatio-temporal control over the location and bioactivity of factors after introduction into the body is crucial to achieve tangible therapeutic effect. Sophisticated materials systems that regulate the biological presentation of growth factors represent an attractive new generation of therapeutic agents for the treatment of a wide variety of diseases. This review provides an overview of growth factor delivery in tissue engineering. Certain fundamental issues and design strategies relevant to the material carriers that are being actively pursued to address specific technical objectives are discussed. Recent progress highlights the importance of materials science and engineering in growth factor delivery approaches to regenerative medicine. PMID: 20719768 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | The formation of protein concentration gradients mediated by density differences of poly(ethylene glycol) microspheres. Biomaterials. 2010 Aug 16; Authors: Roam JL, Xu H, Nguyen PK, Elbert DL A critical element in the formation of scaffolds for tissue engineering is the introduction of concentration gradients of bioactive molecules. We explored the use of poly(ethylene glycol) (PEG) microspheres fabricated via a thermally induced phase separation to facilitate the creation of gradients in scaffolds. PEG microspheres were produced with different densities (buoyancies) and centrifuged to develop microsphere gradients. We previously found that the time to gelation following phase separation controlled the size of microspheres in the de-swollen state, while crosslink density affected swelling following buffer exchange into PBS. The principle factors used here to control microsphere densities were the temperature at which the PEG solutions were reacted following phase separation in aqueous sodium sulfate solutions and the length of the incubation period above the 'cloud point'. Using different temperatures and incubation times, microspheres were formed that self-assembled into gradients upon centrifugation. The gradients were produced with sharp interfaces or gradual transitions, with up to 5 tiers of different microsphere types. For proof-of-concept, concentration gradients of covalently immobilized proteins were also assembled. PEG microspheres containing heparin were also fabricated. PEG-heparin microspheres were incubated with fluorescently labeled protamine and used to form gradient scaffolds. The ability to form gradients in microspheres may prove to be useful to achieve better control over the kinetics of protein release from scaffolds or to generate gradients of immobilized growth factors. PMID: 20719381 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Osteogenic differentiation of intact human amniotic membrane. Biomaterials. 2010 Aug 16; Authors: Lindenmair A, Wolbank S, Stadler G, Meinl A, Peterbauer-Scherb A, Eibl J, Polin H, Gabriel C, van Griensven M, Redl H Tissue engineering strategies usually require cell isolation and combination with a suitable biomaterial. Human amniotic membrane (AM) represents a natural two-layered sheet comprising cells with proven stem cell characteristics. In our approach, we evaluated the differentiation potential of AM in toto with its sessile stem cells as alternative to conventional approaches requiring cell isolation and combination with biomaterials. For this, AM-biopsies were differentiated in vitro using two osteogenic media compared with control medium (CM) for 28 days. Mineralization and osteocalcin expression was demonstrated by (immuno)histochemistry. Alkaline phosphatase (AP) activity, calcium contents and mRNA expression of RUNX2, AP, osteopontin, osteocalcin, BMP-2 (bone morphogenetic protein), and BMP-4 were quantified and AM viability was evaluated. Under osteogenic conditions, AM-biopsies mineralized successfully and by day 28 the majority of cells expressed osteocalcin. This was confirmed by a significant rise in calcium contents (up to 27.4 +/- 6.8 mg/dl d28), increased AP activity, and induction of RUNX2, AP, BMP-2 and BMP-4 mRNA expression. Relatively high levels of viability were retained, especially in osteogenic media (up to 78.3 +/- 19.0% d14; 62.9 +/- 22.3% d28) compared to CM (42.2 +/- 15.2% d14; 35.1 +/- 8.6% d28). By this strategy, stem cells within human AM can successfully be driven along the osteogenic pathways while residing within their natural environment. PMID: 20719379 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Efficacy of periodontal stem cell transplantation in the treatment of advanced periodontitis. Cell Transplant. 2010 Aug 18; Authors: Park JY, Jeon SH, Choung PH Periodontitis is the most common cause for tooth loss in adults and advanced types affect 10% to 15% of adults worldwide. The attempts to save tooth and regenerate the periodontal apparatus including cementum, periodontal ligament and alveolar bone reach to the dental tissue derived stem cell therapy. Although there have been several periodontitis models suggested, the apical involvement of tooth root is especially challenging to be regenerated and dental stem cell therapy for the state has never been investigated. Three kinds of dental tissue derived adult stem cells (aDSCs) were obtained from the extracted immature molars of beagle dogs (n=8), and ex vivo expanded periodontal ligament stem cells (PDLSCs), dental pulp stem cells (DPSCs), and periapical follicular stem cells (PAFSCs) were transplanted into the apical involvement defect. As for the lack of cementum specific markers, anti-human cementum protein 1 (rhCEMP1) antibody was fabricated and the aDSCs and the regenerated tissues were immunostained with anti-CEMP1 antibody. Autologous PDLSCs showed the best regenerating capacity of periodontal ligament, alveolar bone and cementum as well as peripheral nerve and blood vessel which were evaluated by conventional and immune histology, 3D micro CT and clinical index. The rhCEMP1 was expressed strongest in PDLSCs and in the regenerated periodontal ligament space. We suggest here the PDLSCs as the most favorable candidate for the clinical application among the three dental stem cells and can be used for treatment of advanced periodontitis where tooth removal was indicated in the clinical cases. PMID: 20719084 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Locally Administered Adipose-derived Stem Cells Accelerate Wound Healing through Differentiation and Vasculogenesis. Cell Transplant. 2010 Aug 18; Authors: Nie C, Yang D, Xu J, Si Z, Jin X, Zhang J Despite advances in wound closure techniques and devices, there is still a critical need for new methods of enhancing the healing process to achieve optimal outcomes. Recently, stem cell therapy has emerged as a new approach to accelerate wound healing. Adipose-derived stem cells (ASCs) hold great promise for wound healing, which are multipotential stem cells capable of differentiation into various cell lineages and secretion of angiogenic growth factors. The aim of this study was to evaluate the benefit of ASCs on wound healing and then investigate the probable mechanisms. ASCs characterized by flow cytometry were successfully isolated and cultured. An excisional wound healing model in rat was used to determine the effects of locally administered ASCs. The gross and histological results showed that ASCs significantly accelerated wound closure in normal and diabetic rat, including increased epithelialization and granulation tissue deposition. Furthermore, we applied GFP-labeled ASCs on wounds to determine whether ASCs could differentiate along multiple lineages of tissue regeneration in the specific microenvironment. Immunofluorescent analysis indicated that GFP-expressing ASCs were co-stained with pan-cytokeratin and CD31 respectively, indicating spontaneous site-specific differentiation into epithelial and endothelial lineages. These data suggest that ASCs not only contribute to cutaneous regeneration, but also participate in new vessels formation. Moreover, ASCs were found to secret angiogenic cytokines in vitro and in vivo, including VEGF, HGF and FGF2, which increase neovascularization and enhance wound healing in injured tissues. In conclusion, our results demonstrate that ASCs therapy could accelerate wound healing through differentiation and vasculogenesis and might represent a novel therapeutic approach in cutaneous wounds. PMID: 20719083 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Suspension Culture of Mammalian Cells using Thermo-Sensitive Microcarrier that Allows Cell Detachment without Proteolytic Enzyme Treatment. Cell Transplant. 2010 Aug 18; Authors: Yang HS, Jeon O, Bhang SH, Lee SH, Kim BS Microcarriers are used to expand anchorage-dependent cells in large-scale suspension bioreactors. Proteolytic enzyme treatment is necessary to detach cells cultured on microcarriers for cell harvest or scale-up, but the enzyme treatment damages the cells and extracellular matrices and complicates the culture process. Here, we fabricated thermo-sensitive microcarriers from which cells can be detached by temperature change without proteolytic enzyme treatment. A thermo-sensitive polymer, poly-N-isopropylacrylamide (pNIPAAm) was incorporated on the surface of Cytodex-3(R) microcarriers. pNIPAAm-grafted microcarriers allowed human bone marrow-derived mesenchymal stem cells (hBMMSCs) to adhere, spread, and grow successfully on the microcarriers as non-grafted microcarriers did. By dropping temperature below 32 degrees , more than 82.5% of hBMMSCs were detached from pNIPAAm-grafted microcarriers. The trypsin treatment for cell detachment induced apoptosis and death of some of the detached cells, but cell detachment from pNIPAAm-grafted microcarriers by temperature change significantly reduced the apoptosis and cell death. Taken together, pNIPAAm-grafted microcarriers can significantly reduce cell extracellular matrix damage in the cell detachment process and simplify the cell detachment process by avoiding proteolytic enzyme treatment. pNIPAAm-grafted microcarriers would be valuable to a variety of potential fields demanding a large amount of cells without cell damage, such as cell therapy, tissue engineering, and other biological and clinical applications. PMID: 20719079 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Nanofibers and nanoparticles from the insect-capturing adhesive of the Sundew (Drosera) for cell attachment. J Nanobiotechnology. 2010 Aug 18;8(1):20 Authors: Zhang M, Lenaghan SC, Xia L, Dong L, He W, Henson WR, Fan X ABSTRACT: BACKGROUND: The search for naturally occurring nanocomposites with diverse properties for tissue engineering has been a major interest for biomaterial research. In this study, we investigated a nanofiber and nanoparticle based nanocomposite secreted from an insect-capturing plant, the Sundew, for cell attachment. The adhesive nanocomposite has demonstrated high biocompatibility and is ready to be used with minimal preparation. RESULTS: Atomic force microscopy (AFM) conducted on the adhesive from three species of Sundew found that a network of nanofibers and nanoparticles with various sizes existed independent of the coated surface. AFM and light microscopy confirmed that the pattern of nanofibers corresponded to Alcian Blue staining for polysaccharide. Transmission electron microscopy identified a low abundance of nanoparticles in different pattern from AFM observations. In addition, energy-dispersive X-ray spectroscopy revealed the presence of Ca, Mg, and Cl, common components of biological salts. Study of the material properties of the adhesive yielded high viscoelasticity from the liquid adhesive, with reduced elasticity observed in the dried adhesive. The ability of PC12 neuron-like cells to attach and grow on the network of nanofibers created from the dried adhesive demonstrated the potential of this network to be used in tissue engineering, and other biomedical applications. CONCLUSIONS: This discovery demonstrates how a naturally occurring nanofiber and nanoparticle based nanocomposite from the adhesive of Sundew can be used for tissue engineering, and opens the possibility for further examination of natural plant adhesives for biomedical applications. PMID: 20718990 [PubMed - as supplied by publisher] | | | | | | | | | | | | | | | | | | | | | | | | | Classification and comparison of niche services for developing strategy of medical tourism in Asian countries. Int Surg. 2010 Apr-Jun;95(2):108-16 Authors: Chen HC, Kuo HC, Chung KP, Chang S, Su S, Yang MC Medical tourism is a new trend in medical service. It is booming not only in Asian countries but also in European and South American countries. Worldwide competition of medical service is expected in the future, and niche service will be a "trademark" for the promotion of global medicine. Niche service also functions for market segmentation. Niche services are usually surgical procedures. A study was carried out to compare different strategies for developing medical tourism in Asian countries. The role of a niche service is evaluated in the initiation and further development of medical tourism for individual countries. From this study, a general classification was proposed in terms of treatment procedures. It can be used as a useful guideline for additional studies in medical tourism. Niche service plays the following roles in the development of medical tourism: (1) It attracts attention in the mass media and helps in subsequent promotion of business, (2) it exerts pressure on the hospital, which must improve the quality of health care provided in treating foreign patients, especially the niche services, and (3) it is a tool for setting up the business model. E-Da Hospital is an example for developing medical tourism in Taiwan. A side effect is that niche service brings additional foreign patients, which will contribute to the benefit of the hospital, but this leaves less room for treating domestic patients. A niche service is a means of introduction for entry into the market of medical tourism. How to create a successful story is important for the development of a niche service. When a good reputation has been established, the information provided on the Internet can last for a long time and can spread internationally to form a distinguished mark for further development. Niche services can be classified into 3 categories: (1) Low-risk procedures with large price differences and long stay after retirement; (2) high-risk procedures with less of a price difference, and (3) banned procedures that are not allowed legally in home countries of foreign patients, such as stem cell therapy. In establishing a niche service, a high-quality, nonmedical segment should be integrated as well. PMID: 20718315 [PubMed - in process] | | | | | | | | | | | | | | | | | | | | | | | | | Spatiotemporal measurement of freezing-induced deformation of engineered tissues. J Biomech Eng. 2010 Mar;132(3):031003 Authors: Teo KY, Dutton JC, Han B In order to cryopreserve functional engineered tissues (ETs), the microstructure of the extracellular matrix (ECM) should be maintained, as well as the cellular viability since the functionality is closely related to the ECM microstructure. Since the post-thaw ECM microstructure is determined by the deformation of ETs during cryopreservation, freezing-induced deformation of ETs was measured with a newly developed quantum dot (QD)-mediated cell image deformetry system using dermal equivalents as a model tissue. The dermal equivalents were constructed by seeding QD-labeled fibroblasts in type I collagen matrices. After 24 h incubation, the ETs were directionally frozen by exposing them to a spatial temperature gradient (from 4 degrees C to -20 degrees C over a distance of 6 mm). While being frozen, the ETs were consecutively imaged, and consecutive pairs of these images were two-dimensionally cross-correlated to determine the local deformation during freezing. The results showed that freezing induced the deformation of ET, and its magnitude varied with both time and location. The maximum local dilatation was 0.006 s(-1) and was always observed at the phase change interface. Due to this local expansion, the unfrozen region in front of the freezing interface experienced compression. This expansion-compression pattern was observed throughout the freezing process. In the unfrozen region, the deformation rate gradually decreased away from the freezing interface. After freezing/thawing, the ET experienced an approximately 28% decrease in thickness and 8% loss in weight. These results indicate that freezing-induced deformation caused the transport of interstitial fluid, and the interstitial fluid was extruded. In summary, the results suggest that complex cell-fluid-matrix interactions occur within ETs during freezing, and these interactions determine the post-thaw ECM microstructure and eventual post-thaw tissue functionality. PMID: 20459191 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | [The effect of TNF-alpha on TAZ expression and osteogenic potential of mesenchymal stem cells from myeloma patients] Zhonghua Zhong Liu Za Zhi. 2009 Jan;31(1):5-9 Authors: Li BZ, Shi MX, Li J, Ma J, Chen L, Chen B, Zhao CH OBJECTIVE: To explore the relationship between TNF-alpha, transcriptional co-activator with PDZ-binding motif (TAZ) and bone disease of multiple myeloma. METHODS: The biological characteristics, especially the osteogenic potential of marrow MSCs from myeloma patients and normal subjects were studied. Real-time RT-PCR and Western-blot were employed to detect mRNA and protein expression of TAZ in MSCs. The concentration of TNF-alpha in the marrow plasma was detected using ELISA method. CD138(+) myeloma cells were cocultured with normal MSCs with or without anti-human TNF-alpha monoclonal antibody in the Transwell system. Real-time RT-PCR was employed to detect the mRNA expressions of ALP, Cbfa1 and TAZ in MSCs two weeks later. von Kossa staining was used to detect the mineral deposition. TNF-alpha was added into the culture media of normal marrow MSCs and real-time RT-PCR and Western-blot were employed to detect mRNA and protein expression of TAZ in MSCs one week later. RESULTS: Real-time RT-PCR revealed that the mRNA of osteogenic markers was decreased in comparison with that of normal controls after cultured in the osteogenic medium. von Kossa staining showed weakened mineral deposition in MSCs from multiple myeloma patients compared with that in normal subjects after osteogenic differentiation for two weeks. The mRNA and protein levels of TAZ in the MSCs from myeloma patients were decreased. TNF-alpha concentration in the marrow plasma of myeloma patients was higher than that in the normal controls [(355.4 +/- 49.1) vs. (92.3 +/- 17.2) pg/ml]. CD138(+) myeloma cells inhibited mRNA expressions of ALP, Cbfal1 and TAZ in MSCs, which could be partially reversed by anti-human TNF-alpha monoclonal antibody. CONCLUSION: The osteogenic potential of MSCs from myeloma patients is significantly decreased in comparison with that in normal subjects, which may play an important role in the pathology of myeloma bone disease. TAZ expression inhibited by TNF-alpha may play an important role in this inhibition effect. PMID: 19538860 [PubMed - indexed for MEDLINE] | | | | | | | | | |  | |  | |  |
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