|  |  |  | | | | | TERMSC | | | | | | | | | | | | | | | | | | | Oxidative status of muscle is determined by p107 regulation of PGC-1alpha. J Cell Biol. 2010 Aug 23;190(4):651-62 Authors: Scimè A, Soleimani VD, Bentzinger CF, Gillespie MA, Le Grand F, Grenier G, Bevilacqua L, Harper ME, Rudnicki MA Mice lacking p107 exhibit a white adipose deficiency yet do not manifest the metabolic changes typical for lipodystrophy, and instead exhibit low levels of serum triglycerides and a normal liver phenotype. When fed a high fat diet, p107-null mice still did not accumulate fat in the liver, and display markedly elevated energy expenditures together with an increased energy preference for lipids. Skeletal muscle was therefore examined, as this is normally the major tissue involved in whole body lipid metabolism. Notably, p107-deficient muscle express increased levels of peroxisome proliferator-activated receptor gamma co-activator-1alpha (PGC-1alpha) and contained increased numbers of the pro-oxidative type I and type IIa myofibers. Chromatin immunoprecipitation revealed binding of p107 and E2F4 to the PGC-1alpha proximal promoter, and this binding repressed promoter activity in transient transcription assays. Ectopic expression of p107 in muscle tissue in vivo results in a pronounced 20% decrease in the numbers of oxidative type IIa myofibers. Lastly, isolated p107-deficient muscle tissue display a threefold increase in lipid metabolism. Therefore, p107 determines the oxidative state of multiple tissues involved in whole body fat metabolism, including skeletal muscle. PMID: 20713602 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Production of erythriod cells from human embryonic stem cells by fetal liver cell extract treatment. BMC Dev Biol. 2010;10:85 Authors: Liu YX, Yue W, Ji L, Nan X, Pei XT BACKGROUND: We recently developed a new method to induce human stem cells (hESCs) differentiation into hematopoietic progenitors by cell extract treatment. Here, we report an efficient strategy to generate erythroid progenitors from hESCs using cell extract from human fetal liver tissue (hFLT) with cytokines. Human embryoid bodies (hEBs) obtained of human H1 hESCs were treated with cell extract from hFLT and co-cultured with human fetal liver stromal cells (hFLSCs) feeder to induce hematopoietic cells. After the 11 days of treatment, hEBs were isolated and transplanted into liquid medium with hematopoietic cytokines for erythroid differentiation. Characteristics of the erythroid cells were analyzed by flow cytometry, Wright-Giemsa staining, real-time RT-PCR and related functional assays. RESULTS: The erythroid cells produced from hEBs could differentiate into enucleated cells and expressed globins in a time-dependent manner. They expressed not only embryonic globins but also the adult-globin with the maturation of the erythroid cells. In addition, our data showed that the hEBs-derived erythroid cells were able to act as oxygen carriers, indicating that hESCs could generate functional mature erythroid cells. CONCLUSION: Cell extract exposure with the addition of cytokines resulted in robust erythroid -like differentiation of hEBs and these hEBs-derived erythroid cells possessed functions similar to mature red blood cells. PMID: 20696076 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | De novo generation of white adipocytes from the myeloid lineage via mesenchymal intermediates is age, adipose depot, and gender specific. Proc Natl Acad Sci U S A. 2010 Aug 17;107(33):14781-6 Authors: Majka SM, Fox KE, Psilas JC, Helm KM, Childs CR, Acosta AS, Janssen RC, Friedman JE, Woessner BT, Shade TR, Varella-Garcia M, Klemm DJ It is generally assumed that white adipocytes arise from resident adipose tissue mesenchymal progenitor cells. We challenge this paradigm by defining a hematopoietic origin for both the de novo development of a subset of white adipocytes in adults and a previously uncharacterized adipose tissue resident mesenchymal progenitor population. Lineage and cytogenetic analysis revealed that bone marrow progenitor (BMP)-derived adipocytes and adipocyte progenitors arise from hematopoietic cells via the myeloid lineage in the absence of cell fusion. Global gene expression analysis indicated that the BMP-derived fat cells are bona fide adipocytes but differ from conventional white or brown adipocytes in decreased expression of genes involved in mitochondrial biogenesis and lipid oxidation, and increased inflammatory gene expression. The BMP-derived adipocytes accumulate with age, occur in higher numbers in visceral than in subcutaneous fat, and in female versus male mice. BMP-derived adipocytes may, therefore, account in part for adipose depot heterogeneity and detrimental changes in adipose metabolism and inflammation with aging and adiposity. PMID: 20679227 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Arsenic antagonizes the Hedgehog pathway by preventing ciliary accumulation and reducing stability of the Gli2 transcriptional effector. Proc Natl Acad Sci U S A. 2010 Jul 27;107(30):13432-7 Authors: Kim J, Lee JJ, Kim J, Gardner D, Beachy PA Aberrant Hedgehog (Hh) pathway activation has been implicated in cancers of diverse tissues and organs, and the tumor growth-inhibiting effects of pathway antagonists in animal models have stimulated efforts to develop pathway antagonists for human therapeutic purposes. These efforts have focused largely on cyclopamine derivatives or other compounds that mimic cyclopamine action in binding to and antagonizing Smoothened, a membrane transductory component. We report here that arsenicals, in contrast, antagonize the Hh pathway by targeting Gli transcriptional effectors; in the short term, arsenic blocks Hh-induced ciliary accumulation of Gli2, the primary activator of Hh-dependent transcription, and with prolonged incubation arsenic reduces steady-state levels of Gli2. Arsenicals active in Hh pathway antagonism include arsenic trioxide (ATO), a curative agent in clinical use for acute promyelocytic leukemia (APL); in our studies, ATO inhibited growth of Hh pathway-driven medulloblastoma allografts derived from Ptch+/-p53-/- mice within a range of serum levels comparable to those achieved in treatment of human APL. Arsenic thus could be tested rapidly as a therapeutic agent in malignant diseases associated with Hh pathway activation and could be particularly useful in such diseases that are inherently resistant or have acquired resistance to cyclopamine mimics. PMID: 20624968 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Reprogramming adult hematopoietic cells. Curr Opin Hematol. 2010 Jul;17(4):271-5 Authors: Kaneko S, Otsu M, Nakauchi H PURPOSE OF REVIEW: Recent advances in molecular biology research have culminated in development of technologies to generate pluripotent stem cells from somatic cells. In addition to skin fibroblasts, hematopoietic cells also have been shown to be amenable to reprogramming to pluripotency. The present review discusses the relevance of these findings to basic researches and regenerative medicine, and how researchers can take advantage of hematopoietic cell reprogramming technologies. RECENT FINDINGS: In 2006, Yamanaka and his colleagues published their amazing observation that murine somatic cells can be reprogrammed to the embryonic stem cell-like state simply by retroviral-mediated introduction of three or four defined factors. Soon after, human cells also were shown to be amenable to similar reprogramming. Generation of induced pluripotent cells from several types of hematopoietic cells of both murine and human origins now has been reported. SUMMARY: Reprogramming adult hematopoietic cells will provide opportunities to obtain valuable materials with minimum risk and burden to patients. Reprogrammed cells can be used in research to elucidate disease mechanisms and in drug or toxicity screening. In clinical settings, patient-derived induced pluripotent stem cells may be used to generate mature functional cells for various therapies. PMID: 20571391 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Factory neovessels: engineered human blood vessels secreting therapeutic proteins as a new drug delivery system. Gene Ther. 2010 Jun;17(6):745-51 Authors: Compte M, Alonso-Camino V, Santos-Valle P, Cuesta AM, Sánchez-MartÃn D, López MR, Vicario JL, Salas C, Sanz L, Alvarez-Vallina L Several works have shown the feasibility of engineering functional blood vessels in vivo using human endothelial cells (ECs). Going further, we explored the therapeutic potential of neovessels after gene-modifying the ECs for the secretion of a therapeutic protein. Given that these vessels are connected with the host vascular bed, we hypothesized that systemic release of the expressed protein is immediate. As a proof of principle, we used primary human ECs transduced with a lentiviral vector for the expression of a recombinant bispecific alphaCEA/alphaCD3 antibody. These ECs, along with mesenchymal stem cells as a source of mural cells, were embedded in Matrigel and subcutaneously implanted in nude mice. High antibody levels were detected in plasma for 1 month. Furthermore, the antibody exerted a therapeutic effect in mice bearing distant carcinoembryonic-antigen (CEA)-positive tumors after inoculation of human T cells. In summary, we show for the first time the therapeutic effect of a protein locally secreted by engineered human neovessels. PMID: 20336155 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Structural and cellular features in metaphyseal and diaphyseal periosteum of osteoporotic rats. J Mol Histol. 2010 Feb;41(1):51-60 Authors: Fan W, Bouwense SA, Crawford R, Xiao Y Despite the important physiological role of periosteum in the pathogenesis and treatment of osteoporosis, little is known about the structural and cellular characteristics of periosteum in osteoporosis. To study the structural and cellular differences in both diaphyseal and metaphyseal periosteum of osteoporotic rats, samples from the right femur of osteoporotic and normal female Lewis rats were collected and tissue sections were stained with hematoxylin and eosin, antibodies or staining kit against tartrate resistant acid phosphatase (TRAP), alkaline phosphatase (ALP), vascular endothelial growth factor (VEGF), von Willebrand (vWF), tyrosine hydroxylase (TH) and calcitonin gene-related peptide (CGRP). The results showed that the osteoporotic rats had much thicker and more cellular cambial layer of metaphyseal periosteum compared with other periosteal areas and normal rats (P < 0.001). The number of TRAP(+) osteoclasts in bone resorption pits, VEGF(+) cells and the degree of vascularization were found to be greater in the cambial layer of metaphyseal periosteum of osteoporotic rats (P < 0.05), while no significant difference was detected in the number of ALP(+) cells between the two groups. Sympathetic nerve fibers identified by TH staining were predominantly located in the cambial layer of metaphyseal periosteum of osteoporotic rats. No obvious difference in the expression of CGRP between the two groups was found. In conclusion, periosteum may play an important role in the cortical bone resorption in osteoporotic rats and this pathological process may be regulated by the sympathetic nervous system. PMID: 20232237 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation of in-vivo tissue-engineered valved conduit with the sinus of Valsalva (type IV biovalve). J Artif Organs. 2010 Jul;13(2):106-12 Authors: Yamanami M, Yahata Y, Tajikawa T, Ohba K, Watanabe T, Kanda K, Yaku H, Nakayama Y A novel autologous valved conduit with the sinus of Valsalva-defined as a type IV biovalve-was created in rabbits by "in-body tissue-architecture" technology with a specially designed mold for the valve leaflets and the sinus of Valsalva and a microporous tubular scaffold for the conduit. The mold included 2 rods composed of silicone substrates. One was concave shaped, with 3 projections resembling the sinus of Valsalva; the other was convex shaped. The connection between the rods was designed to resemble the closed form of a trileaflet valve. The 2 rods were connected with a small aperture of 500-800 microm, which bound membranous connective tissue obtained from the dorsal subcutaneous layer of a rabbit. The rods were placed in a polyurethane scaffold that had many windows in its center. Both ends of the scaffold were tied with thread for fixation, and this assembly was embedded for 1 month in a subcutaneous pouch in the same Japanese white rabbit from which the connective tissue was obtained. After 1 month, all the surfaces of the implant were found to be completely covered with newly developed connective tissue. The substrates were removed from both sides of the harvested cylindrical implant, and homogenous well-balanced trileaflet-shaped membranous tissue was found inside the developed conduit with 3 protrusions resembling the sinus of Valsalva. The trileaflet valve closed and opened rapidly in synchrony with the backward and forward flow of a pulsatile flow circuit in vitro. PMID: 20213453 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Strategies for ensuring that regenerative cardiomyocytes function properly and in cooperation with the host myocardium. Exp Mol Med. 2010 Mar 31;42(3):155-65 Authors: Hattori F, Fukuda K In developed countries, in which people have nutrient-rich diets, convenient environments, and access to numerous medications, the disease paradigm has changed. Nowadays, heart failure is one of the major causes of death. In spite of this, the therapeutic efficacies of medications are generally unsatisfactory. Although whole heart transplantation is ideal for younger patients with heart failure, many patients are deemed to be unsuitable for this type of surgery due to complications and/or age. The need for therapeutic alternatives to heart transplantation is great. Regenerative therapy is a strong option. For this purpose, several cell sources have been investigated, including intrinsic adult stem or progenitor cells and extrinsic pluripotent stem cells. Most intrinsic stem cells seem to contribute to a regenerative environment via paracrine factors and/or angiogenesis, whereas extrinsic pluripotent stem cells are unlimited sources of cardiomyocytes. In this review, we summarize the various strategies for using regenerative cardiomyocytes including our recent progressions: non-genetic approaches for the purification of cardiomyocytes and efficient transplantation. We expect that use of intrinsic and extrinsic stem cells in combination will enhance therapeutic effectiveness. PMID: 20164677 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Design and testing of biological scaffolds for delivering reparative cells to target sites in the lung. J Tissue Eng Regen Med. 2010 Jun;4(4):259-72 Authors: Ingenito EP, Sen E, Tsai LW, Murthy S, Hoffman A This study summarizes the development and testing of a scaffold to promote engraftment of cells in the distal lung. A fibrinogen-fibronectin-vitronectin hydrogel (FFVH) was developed and optimized with respect to its mechanical and biological properties for this application. In vitro, FFVH scaffolds promoted attachment, histiotypic growth and expression of basement membrane proteins by primary ovine lung mesenchymal cells derived from lung biopsies. In vivo testing was then performed to assess the ability of FFVHs to promote cell engraftment in the sheep lung. Treatment with autologous cells delivered using FFVH was clinically well tolerated. Cells labelled with a fluorescent dye (PKH-26) were detected at treatment sites after 1 month. Tissue mass (assessed by CT imaging) and lung perfusion (assessed by nuclear scintigraphy) were increased at emphysema test sites. Post-treatment histology demonstrated cell proliferation and increased elastin expression without scarring or collapse. No treatment-related pathology was observed at healthy control sites. FFVH scaffolds promote cell attachment, spreading and extracellular matrix expression in vitro and apparent engraftment in vivo, with evidence of trophic effects on the surrounding tissue. Scaffolds of this type may contribute to the development of cell-based therapies for patients with end-stage pulmonary diseases. PMID: 20020503 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The importance of specific biomolecules for enhancing tissue growth is well recognized and there have been notable studies on the incorporation of small molecule factors as coatings on scaffolds to help in tissue regeneration. Tissue Eng Part A. 2010 Feb;16(2):355-6 Authors: Nair SV PMID: 19947853 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | The effect of insulin-loaded chitosan particle-aggregated scaffolds in chondrogenic differentiation. Tissue Eng Part A. 2010 Feb;16(2):735-47 Authors: Malafaya PB, Oliveira JT, Reis RL Osteochondral defect repair requires a tissue engineering approach that aims at mimicking the physiological properties and structure of two different tissues (cartilage and bone) using a scaffold-cell construct. One ideal approach would be to engineer in vitro a hybrid material using a single-cell source. For that purpose, the scaffold should be able to provide the adequate biochemical cues to promote the selective but simultaneous differentiation of both tissues. In this work, attention was paid primarily to the chondrogenic differentiation by focusing on the development of polymeric systems that provide biomolecules release to induce chondrogenic differentiation. For that, different formulations of insulin-loaded chitosan particle-aggregated scaffolds were developed as a potential model system for cartilage and osteochondral tissue engineering applications using insulin as a potent bioactive substance known to induce chondrogenic differentiation. The insulin encapsulation efficiency was shown to be high with values of 70.37 +/- 0.8%, 84.26 +/- 1.76%, and 87.23 +/- 1.58% for loadings of 0.05%, 0.5%, and 5%, respectively. The in vitro release profiles were assessed in physiological conditions mimicking the cell culture procedures and quantified by Micro-BCA protein assay. Different release profiles were obtained that showed to be dependent on the initial insulin-loading percentage. Further, the effect on prechondrogenic ATDC5 cells was investigated for periods up to 4 weeks by studying the influence of these release systems on cell morphology, DNA and glycosaminoglycan content, histology, and gene expression of collagen types I and II, Sox-9, and aggrecan assessed by real-time polymerase chain reaction. When compared with control conditions (unloaded scaffolds cultured with the standard chondrogenic-inducing medium), insulin-loaded scaffolds upregulated the Sox-9 and aggrecan expression after 4 weeks of culture. From the overall results, it is reasonable to conclude that the developed loaded scaffolds when seeded with ATDC5 can provide biochemical cues for chondrogenic differentiation. Among the tested formulations, the higher insulin-loaded system (5%) was the most effective in promoting chondrogenic differentiation. PMID: 19772454 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Engineering a titanium and polycaprolactone construct for a biocompatible interface between the body and artificial limb. Tissue Eng Part A. 2010 Feb;16(2):717-24 Authors: Smith CM, Roy TD, Bhalkikar A, Li B, Hickman JJ, Church KH Intraosseous transcutaneous amputation prostheses may be able to overcome the problems that stem from the nonuniform distribution of pressure seen in the conventional stump-socket prosthetic replacement devices. Transcutaneous devices have had limited success in amputees. By optimizing the attachment of the skin to the prosthetic, intraosseous transcutaneous amputation prostheses may become clinically viable options. This report details studies evaluating the development of a modified titanium construct with a specially machined surface to increase the adherence of tissue as well as scaffold. A computer-aided biology tool was used to fabricate polycaprolactone (PCL) scaffolds with a specific three-dimensional architecture. To extrude the PCL, it was dissolved in acetic acid to produce a 70% PCL liquid. A scaffold with a porosity of >50% was fabricated to have a tensile strength similar to skin. The presence of a specially machined surface greatly increased the adhesion of the PCL scaffold to the titanium constructs. When the 70% PCL was properly neutralized by heating at 55 degrees C and washing in 90% ethanol (EtOH), there was only a decrease (10%) in the viability of cells seeded onto the PCL constructs when compared with the cells in culture. The antibacterial properties of titanium dioxide anatase, silver nanoparticles, and chlorhexidine diacetate mixed in either type I collagen or hyaluronic acid (HA) were assessed. The addition of 1% (w/w) chlorhexidine diacetate in HA resulted in a 71% decrease in bacteria seen in nontreated HA. These results show promise in developing a novel engineered titanium and PCL construct that promotes effective adhesion between the titanium-skin interface. PMID: 19769529 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Rapid anastomosis of endothelial progenitor cell-derived vessels with host vasculature is promoted by a high density of cotransplanted fibroblasts. Tissue Eng Part A. 2010 Feb;16(2):585-94 Authors: Chen X, Aledia AS, Popson SA, Him L, Hughes CC, George SC To ensure survival of engineered implantable tissues thicker than approximately 2-3 mm, convection of nutrients and waste products to enhance the rate of transport will be required. Creating a network of vessels in vitro, before implantation (prevascularization), is one potential strategy to achieve this aim. In this study, we developed three-dimensional engineered vessel networks in vitro by coculture of endothelial cells (ECs) and fibroblasts in a fibrin gel for 7 days. Vessels formed by cord blood endothelial progenitor cell-derived ECs (EPC-ECs) in the presence of a high density of fibroblasts created an interconnected tubular network within 4 days, compared with 5-7 days in the presence of a low density of fibroblasts. Vessels derived from human umbilical vein ECs (HUVECs) in vitro showed similar kinetics. Implantation of the prevascularized tissues into immune-compromised mice, however, revealed a dramatic difference in the ability of EPC-ECs and HUVECs to form anastomoses with the host vasculature. Vascular beds derived from EPC-ECs were perfused within 1 day of implantation, whereas no HUVEC vessels were perfused at day 1. Further, while almost 90% of EPC-EC-derived vascular beds were perfused at day 3, only one-third of HUVEC-derived vascular beds were perfused. In both cases, a high density of fibroblasts accelerated anastomosis by 2-3 days. We conclude that both EPC-ECs and a high density of fibroblasts significantly accelerate the rate of functional anastomosis, and that prevascularizing an engineered tissue may be an effective strategy to enhance convective transport of nutrients in vivo. PMID: 19737050 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Dynamic culture of osteogenic cells in biomimetically coated poly(caprolactone) nanofibre mesh constructs. Tissue Eng Part A. 2010 Feb;16(2):557-63 Authors: Araujo JV, Cunha-Reis C, Rada T, da Silva MA, Gomes ME, Yang Y, Ashammakhi N, Reis RL, El-Haj AJ, Neves NM In our previous work, biomimetic calcium phosphate-coated poly(caprolactone) nanofibre meshes (BCP-NMs) were demonstrated to be more effective for supporting cell attachment and proliferation under static conditions, when compared with poly(caprolactone) nanofibre meshes (PCL-NMs). In many applications, in vitro cultivation of constructs using bioreactors that support efficient nutrition of cells has appeared as an important step toward the development of functional grafts. This work aimed at studying the effects of dynamic culture conditions and biomimetic coating on bone cells grown on the nanofibre meshes. BCP-NM and PCL-NM were seeded with osteoblast-like cells (MG63--human osteosarcoma-derived cell line). The cell-seeded constructs were cultured within a rotating bioreactor that simulated microgravity, at a fixed rotating speed, for different time periods, and then characterized. Cell morphology, viability, and phenotype were assessed. PCL-NM constructs presented a higher number of dead cells than BCP-NM constructs. Under dynamic conditions, the production of proteins associated with the extracellular matrix of bone was higher on BCP-NM constructs than in the PCL-NM ones, which indicates that coated samples may provide cells with a better environment for tissue growth. It is suggested that improved mass transfer in the bioreactor in combination with the appropriate substrate were decisive factors for this highly positive outcome for generating bone. PMID: 19728792 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Membrane-based cultures generate scaffold-free neocartilage in vitro: influence of growth factors. Tissue Eng Part A. 2010 Feb;16(2):513-21 Authors: Mayer-Wagner S, Schiergens TS, Sievers B, Docheva D, Schieker M, Betz OB, Jansson V, Müller PE Scaffold-free cultures provide promising potential in chondrogenic differentiation of human mesenchymal stem cells (hMSCs). In this study, a novel scaffold-free membrane-based culture system, in which hMSCs were cultivated on a cellulose acetate membrane filter at medium-gas interface, was evaluated for chondrogenesis under the addition of growth factors. Chondrogenic differentiation of hMSCs has been described in scaffold-free pellet cultures with good results. In our study membrane-based cultures (1 x 10(6) hMSCs) were produced, maintained at the medium-gas interface and cultured for 21 days. Results were compared with findings from standard pellet cultures (2.5 x 10(5) hMSCs). The effects of the following growth factors were examined: human transforming growth factor-beta(3) (TGF-beta(3)) +/- insulin-like growth factor-1 or +/- human fibroblast growth factor 2. After 3 weeks of culture, chondrogenesis was assessed by Safranin-O staining, immunohistochemistry, a dimethylmethylene blue dye binding assay for glycosaminoglycans, and quantitative real-time polymerase chain reaction for cartilage-specific proteins. Membrane-based cultures containing growth factors formed hemispherical structures with a large surface area (65 mm(2)). When removed from the membrane they showed a histologically smooth cartilage-like surface. Membrane-based cultures stained positive for Safranin-O and collagen type II and contained a high content of glycosaminoglycans. Expression of cartilage-specific markers like collagen type II, aggrecan, and SOX9 was observed under the addition of TGF-beta(3), whereas combinations of growth factors let to a significant increase of collagen type II expression. A markedly reduced expression of collagen type X was found in membrane-based cultures when only TGF-beta(3) was added. Pellet cultures showed similar results besides an increased expression of collagen type X and type II that were observed. Membrane-based cultures provide a differentiation system, comparable in chondrogenesis to pellet cultures, which is able to generate scaffold-free neocartilage. The key benefit factors of membrane-based cultures are a histologically smooth cartilage-like surface and reduced expression of collagen type X, both of which are suitable features for its future application in cartilage regeneration. PMID: 19715388 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Expression of versican isoform V3 in the absence of ascorbate improves elastogenesis in engineered vascular constructs. Tissue Eng Part A. 2010 Feb;16(2):501-12 Authors: Keire PA, L'Heureux N, Vernon RB, Merrilees MJ, Starcher B, Okon E, Dusserre N, McAllister TN, Wight TN A promising method to fabricate tissue-engineered blood vessels is to have cells synthesize the supportive extracellular matrix scaffold of the tissue-engineered blood vessel; however, a shortcoming of this method has been limited elastogenesis. Previously, we found that arterial smooth muscle cells (ASMCs) produced significant quantities of elastin when transduced with splice variant 3 of the proteoglycan versican (V3). In this study, we assessed whether elastogenesis and the structural properties of entirely cell-derived engineered vascular constructs could be improved by the incorporation of V3-transduced rat ASMCs. After 18 weeks of culture, V3 constructs had more tropoelastin, more elastin crosslinks, higher burst strengths, greater elasticity, and thicker collagen fiber bundles compared with empty-vector controls. The expression of elastin and elastin-associated proteins was increased in V3 and control ASMC monolayer cultures when ascorbic acid, which promotes collagen synthesis and inhibits elastogenesis, was removed from the medium. Engineered vascular constructs with ascorbate withdrawn for 14 weeks, after an initial 4-week exposure to ascorbate, exhibited increased elastin, desmosine content, elasticity, and burst strength compared with constructs exposed continuously to ascorbate. Our results show that V3 coupled with limited exposure to ascorbate promotes elastogenesis and improves the structural and functional properties of engineered vascular constructs. PMID: 19712046 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Preparation of cardiac extracellular matrix from an intact porcine heart. Tissue Eng Part C Methods. 2010 Jun;16(3):525-32 Authors: Wainwright JM, Czajka CA, Patel UB, Freytes DO, Tobita K, Gilbert TW, Badylak SF Whole organ engineering would benefit from a three-dimensional scaffold produced from intact organ-specific extracellular matrix (ECM). The microenvironment and architecture provided by such a scaffold would likely support site-appropriate cell differentiation and spatial organization. The methods to produce such scaffolds from intact organs require customized decellularization protocols. In the present study, intact adult porcine hearts were successfully decellularized in less than 10 h using pulsatile retrograde aortic perfusion. Serial perfusion of an enzymatic, nonionic detergent, ionic detergent, and acid solution with hypotonic and hypertonic rinses was used to systematically remove cellular content. The resultant cardiac ECM retained collagen, elastin, and glycosaminoglycans, and mechanical integrity. Cardiac ECM supported the formation of organized chicken cardiomyocyte sarcomere structure in vitro. The intact decellularized porcine heart provides a tissue engineering template that may be beneficial for future preclinical studies and eventual clinical applications. PMID: 19702513 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Cardiomyoblast-like cells differentiated from human adipose tissue-derived mesenchymal stem cells improve left ventricular dysfunction and survival in a rat myocardial infarction model. Tissue Eng Part C Methods. 2010 Jun;16(3):417-25 Authors: Okura H, Matsuyama A, Lee CM, Saga A, Kakuta-Yamamoto A, Nagao A, Sougawa N, Sekiya N, Takekita K, Shudo Y, Miyagawa S, Komoda H, Okano T, Sawa Y Adipose tissue-derived mesenchymal stem cells (ADMSCs) are multipotent cells. Here we examined whether human ADMSCs (hADMSCs) could differentiate into cardiomyoblast-like cells (CLCs) by induction with dimethylsulfoxide and whether the cells would be utilized to treat cardiac dysfunction. Dimethylsulfoxide induced the expression of various cardiac markers in hADMSCs, such as alpha-cardiac actin, cardiac myosin light chain, and myosin heavy chain; none of which were detected in noncommitted hADMSCs. The induced cells were thus designated as hADMSC-derived CLCs (hCLCs). To confirm their beneficial effect on cardiac function, hCLC patches were transplanted onto the Nude rat myocardial infarction model, and compared with noncommitted hADMSC patch transplants and sham operations. Echocardiography demonstrated significant short-term improvement of cardiac function in both the patch-transplanted groups. However, long-term follow-up showed rescue and maintenance of cardiac function in the hCLC patch-transplanted group only, but not in the noncommitted hADMSC patch-transplanted animals. The hCLCs, but not the hADMSCs, engrafted into the scarred myocardium and differentiated into human cardiac troponin I-positive cells, and thus regarded as cardiomyocytes. Transplantation of the hCLC patches also resulted in recovery of cardiac function and improvement of long-term survival rate. Thus, transplantation of hCLC patches is a potentially effective therapeutic strategy for future cardiac tissue regeneration. PMID: 19624256 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | Noninvasive evaluation of tissue-engineered cartilage with time-resolved laser-induced fluorescence spectroscopy. Tissue Eng Part C Methods. 2010 Jun;16(3):365-73 Authors: Kutsuna T, Sato M, Ishihara M, Furukawa KS, Nagai T, Kikuchi M, Ushida T, Mochida J Regenerative medicine requires noninvasive evaluation. Our objective is to investigate the application of time-resolved laser-induced fluorescence spectroscopy (TR-LIFS) using a nano-second-pulsed laser for evaluation of tissue-engineered cartilage (TEC). To prepare scaffold-free TEC, articular chondrocytes from 4-week-old Japanese white rabbits were harvested, and were inoculated at a high density in a mold. Cells were cultured for 5 weeks by rotating culture (RC) or static culture (SC). The RC group and SC group at each week (n = 5), as well as normal articular cartilage and purified collagen type II (as controls), were analyzed by TR-LIFS. The peak wavelength was compared with those of type II collagen immunostaining and type II collagen quantification by enzyme-linked immunosorbent assay and tensile testing. The fluorescence peak wavelength of the TEC analyzed by this method shifted significantly in the RC group at 3 weeks, and in the SC group at 5 weeks (p < 0.01). These results correlated with changes in type II collagen (enzyme-linked immunosorbent assay) and changes in Young's modulus on tensile testing. The results were also supported by immunohistologic findings (type II collagen staining). Our findings show that TR-LIFS is useful for evaluating TEC. PMID: 19589126 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A novel technology and stereotactic accessory for implanting engineered tissues, cells, and scaffold materials into the brain. Tissue Eng Part C Methods. 2010 Jun;16(3):469-70 Authors: Jozwiak A, Gates MA, Liu Y, Yang Y PMID: 19686054 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | A synthetic scaffold favoring chondrogenic phenotype over a natural scaffold. Tissue Eng Part A. 2010 Feb;16(2):373-84 Authors: Mohan N, Nair PD The three-dimensional scaffolds play a very important role in regulating cell adhesion and the production of extracellular matrix molecules in in vitro regeneration of cartilage. This study evaluates how the three-dimensional structure and physicochemical properties of the polymeric scaffolds influence in vitro regeneration of cartilage tissue. A synthetic poly(vinyl alcohol)-poly(caprolactone) semi-interpenetrating polymer network (IPN) scaffold and gelatin-albumin, made of natural polymers, are used for the study. The polymers in the semi-IPN synthetic scaffold mimic the properties of collagen and glycosaminoglycans present in native cartilage. Its appropriate swelling and pore structure enabled cell-cell and cell-matrix interactions. This helped the chondrocytes to retain its spherical morphology and resulted in enhanced secretion of extracellular matrix components. In contrast, the biomimetic structure in gelatin-albumin scaffold induced chondrocytes to loose its phenotype by spreading and becoming fibroblastic in morphology. Its high swelling and the large pore size failed to recreate an appropriate microenvironment for chondrogenesis that resulted in less secretion of cartilage-specific molecules. Mesenchymal stem cell differentiation to chondrocytes in the presence of growth factors is also enhanced in the synthetic semi-IPN scaffold. The study thus indicates that the chemical composition and the physicochemical properties of the scaffolds play a very important role in providing appropriate niche in in vitro tissue regeneration. PMID: 19566439 [PubMed - indexed for MEDLINE] | | | | | | | | | | | | | | | | | | | | | | | | | | | | |  | |  | |  |
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