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| Chronic wound healing by fetal cell therapy may be explained by differential gene profiling observed in fetal versus old skin cells.
February 23, 2010 at 12:00 PM
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| | Chronic wound healing by fetal cell therapy may be explained by differential gene profiling observed in fetal versus old skin cells. Exp Gerontol. 2009 Mar;44(3):208-18 Authors: Ramelet AA, Hirt-Burri N, Raffoul W, Scaletta C, Pioletti DP, Offord E, Mansourian R, Applegate LA Engineering of fetal tissue has a high potential for the treatment of acute and chronic wounds of the skin in humans as these cells have high expansion capacity under simple culture conditions and one organ donation can produce Master Cell Banks which can fabricate over 900 million biological bandages (9 x 12cm). In a Phase 1 clinical safety study, cases are presented for the treatment of therapy resistant leg ulcers. All eight patients, representing 13 ulcers, tolerated multiple treatments with fetal biological bandages showing no negative secondary effects and repair processes similar to that seen in 3rd degree burns. Differential gene profiling using Affymetrix gene chips (analyzing 12,500 genes) were accomplished on these banked fetal dermal skin cells compared to banked dermal skin cells of an aged donor in order to point to potential indicators of wound healing. Families of genes involved in cell adhesion and extracellular matrix, cell cycle, cellular signal! ing, development and immune response show significant differences in regulation between banked fetal and those from banked old skin cells: with approximately 47.0% of genes over-expressed in fetal fibroblasts. It is perhaps these differences which contribute to efficient tissue repair seen in the clinic with fetal cell therapy. PMID: 19049860 [PubMed - indexed for MEDLINE] | | |
| Stem cell and progenitor cell therapy in peripheral artery disease. A critical appraisal.
February 23, 2010 at 12:00 PM
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| | Stem cell and progenitor cell therapy in peripheral artery disease. A critical appraisal. Thromb Haemost. 2010 Feb 19;103(4) Authors: Lawall H, Bramlage P, Amann B Atherosclerotic peripheral artery disease (PAD) is a common manifestation of atherosclerosis. The occlusion of large limb arteries leads to ischaemia with claudication which can progress to critical limb ischaemia (CLI) with pain at rest, and to tissue loss. At present, common therapy for CLI is either surgical or endovascular revascularisation aimed at improving blood flow to the affected extremity. However, major amputation and death are still frequent complications. Exploring new strategies for revascularisation of ischaemic limbs is thus of major importance. Bone marrow (BM)-derived stem and progenitor cells have been identified as a potential new therapeutic option to induce therapeutic angiogenesis. Encouraging results of preclinical studies have rapidly led to several small clinical trials, in which BM-derived mononuclear cells were administered to patients with limb ischaemia. Clinical benefits were reported from these trials including improvement of ankle! -brachial index (ABI), transcutaneous partial pressure of oxygen (TcPO2), reduction of pain, and decreased need for amputation. Nonetheless, large randomised, placebo-controlled, double-blind studies are necessary and currently ongoing (BONMOT-CLI, JUVENTUS and NCT00498069). Further research relates to the optimal cell type and dosage, the isolation method, the role of colony-stimulating factors, administration route, and the supportive stimulation of cells with reduced functioning due to advanced PAD. Autologous stem cell therapy for ischaemic peripheral disease seems to be a promising new tool for the treatment of severe limb ischaemia. Preliminary evidence has established its safety, feasibility and effectiveness on several important endpoints. Several large endpoints studies are underway to further consolidate this evidence. PMID: 20174766 [PubMed - as supplied by publisher] | | |
| Stem cell therapy for type 1 diabetes mellitus.
February 23, 2010 at 12:00 PM
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| | Stem cell therapy for type 1 diabetes mellitus. Nat Rev Endocrinol. 2010 Mar;6(3):139-48 Authors: Aguayo-Mazzucato C, Bonner-Weir S The use of stem cells in regenerative medicine holds great promise for the cure of many diseases, including type 1 diabetes mellitus (T1DM). Any potential stem-cell-based cure for T1DM should address the need for beta-cell replacement, as well as control of the autoimmune response to cells which express insulin. The ex vivo generation of beta cells suitable for transplantation to reconstitute a functional beta-cell mass has used pluripotent cells from diverse sources, as well as organ-specific facultative progenitor cells from the liver and the pancreas. The most effective protocols to date have produced cells that express insulin and have molecular characteristics that closely resemble bona fide insulin-secreting cells; however, these cells are often unresponsive to glucose, a characteristic that should be addressed in future protocols. The use of mesenchymal stromal cells or umbilical cord blood to modulate the immune response is already in clinical trials; howe! ver, definitive results are still pending. This Review focuses on current strategies to obtain cells which express insulin from different progenitor sources and highlights the main pathways and genes involved, as well as the different approaches for the modulation of the immune response in patients with T1DM. PMID: 20173775 [PubMed - in process] | | |
| Erythropoietin receptor response circuits.
February 23, 2010 at 12:00 PM
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| | Erythropoietin receptor response circuits. Curr Opin Hematol. 2010 Feb 18; Authors: Wojchowski DM, Sathyanarayana P, Dev A PURPOSE OF REVIEW: In 1985-1989, erythropoietin (EPO), its receptor (EPOR), and janus kinase 2 were cloned; established to be essential for definitive erythropoiesis; and initially intensely studied. Recently, new impetus, tools, and model systems have emerged to re-examine EPO/EPOR actions, and are addressed in this review. Impetus includes indications that EPO affects significantly more than standard erythroblast survival pathways, the development of novel erythropoiesis-stimulating agents, increasing evidence for EPO/EPOR cytoprotection of ischemically injured tissues, and potential EPO-mediated worsening of tumorigenesis. RECENT FINDINGS: New findings are reviewed in four functional contexts: (pro)erythroblast survival mechanisms, new candidate EPO/EPOR effects on erythroid cell development and new EPOR responses, EPOR downmodulation and trafficking, and novel erythropoiesis-stimulating agents. SUMMARY: As Current Opinion, this monograph seeks to summarize, an! d provoke, new EPO/EPOR action concepts. Specific problems addressed include: beyond (and before) BCL-XL, what key survival factors are deployed in early-stage proerythroblasts? Are distinct EPO/EPOR signals transduced in stage-selective fashions? Is erythroblast proliferation also modulated by EPO/EPOR signals? What functions are subserved by new noncanonical EPO/EPOR response factors (e.g. podocalyxin like-1, tribbles 3, reactive oxygen species, and nuclear factor kappa B)? What key regulators mediate EPOR inhibition and trafficking? And for emerging erythropoiesis-stimulating agents, to what extent do activities parallel EPOs (or differ in advantageous, potentially complicating ways, or both)? PMID: 20173635 [PubMed - as supplied by publisher] | | |
| Toll-like receptor 2 mediates mesenchymal stem cell associated myocardial recovery and VEGF production following acute ischemia/reperfusion injury.
February 23, 2010 at 12:00 PM
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| | Toll-like receptor 2 mediates mesenchymal stem cell associated myocardial recovery and VEGF production following acute ischemia/reperfusion injury. Am J Physiol Heart Circ Physiol. 2010 Feb 19; Authors: Abarbanell AM, Wang Y, Herrmann JL, Weil BR, Poynter JA, Manukyan MC, Meldrum DR Toll-like receptor 2 (TLR2), a key component of the innate immune system, is linked to inflammation and myocardial dysfunction after ischemia/reperfusion injury (I/R). Treatment of the heart with mesenchymal stem cells (MSC) is known to improve myocardial recovery after I/R in part by paracrine factors such as VEGF. However, it is unknown whether TLR2 activation on the MSC affects MSC-mediated myocardial recovery and VEGF production. We hypothesized that knockout of TLR2 on the MSC (TLR2KO MSC) would: 1) improve MSC-mediated myocardial recovery and 2) increase myocardial and MSC VEGF release. Using the isolated heart perfusion system, Sprague-Dawley rat hearts were subjected to I/R and received one of three intracoronary treatments: vehicle, male wild-type MSC (MWT MSC) or TL2KO MSC. All treatments were performed immediately prior to ischemia, and heart function was measured continuously. Post-reperfusion, heart homogenates were analyzed for myocardial VEGF produc! tion. Contrary to our hypothesis, only MWT MSC treatment significantly improved recovery of left ventricular developed pressure (LVDP) and +/- dP/dt. In addition VEGF production was greatest in hearts treated with MWT MSC. To investigate MSC production of VEGF, MSC were activated with TNF in vitro, and the supernatants collected for ELISA. In vitro basal levels of MSC VEGF production were similar. However with TNF activation, MWT MSC produced significantly more VEGF, while activated TLR2KO MSC production of VEGF was unchanged. Finally, we observed that MWT MSC proliferated more rapidly than TLR2KO MSC. These data indicate that TLR2 may be essential to MSC mediated myocardial recovery and VEGF production. Key words: innate immunity, inflammation, stem cell therapy, paracrine signaling. PMID: 20173040 [PubMed - as supplied by publisher] | | |
| Functional testing of a tissue-engineered vocal fold cover replacement.
February 23, 2010 at 12:00 PM
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| | Functional testing of a tissue-engineered vocal fold cover replacement. Otolaryngol Head Neck Surg. 2010 Mar;142(3):438-440 Authors: Long JL, Neubauer J, Zhang Z, Zuk P, Berke GS, Chhetri DK OBJECTIVES: Tissue engineering may provide a treatment for severe vocal fold scars. This study quantifies mechanical properties and demonstrates vibration of a tissue-engineered vocal fold cover replacement. METHODS: Tissue-engineered constructs were produced from fibrin and adipose-derived stem cells. Optimized bilayered constructs contained epithelial and mesenchymal cell phenotypes in a stratified geometry. For comparison, homogeneous constructs did not have epithelial differentiation. Elastic modulus was determined using indentation. Immunohistochemical labeling for type I collagen was performed. A bilayered construct was also tested in phonation in an excised larynx model. RESULTS: Bilayered vocal fold cover replacements had indentation moduli similar to human vocal fold covers (mean construct modulus 6.8 kPa). Collagen deposition occurred in the middle of the construct. Homogeneous constructs had a mean modulus of 8.3 kPa, and collagen was concentrated at th! e surface. An excised larynx with unilateral vocal fold cover replacement phonated and exhibited mucosal waves at physiologic airflow. CONCLUSION: Bilayered tissue-engineered constructs were produced that exhibited indentation modulus, microstructure, and vibration similar to that exhibited by human vocal fold covers. PMID: 20172395 [PubMed - as supplied by publisher] | | |
| Donor Compensation: An Ethical Imperative!
February 23, 2010 at 12:00 PM
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| | Donor Compensation: An Ethical Imperative! Transplant Proc. 2010 January - February;42(1):124-125 Authors: Reichardt JO The number of living organ donors is increasing worldwide, but donor needs are widely neglected in support of anticommodification policies. This article argues that the warrant of donor autonomy during the decision process to donate is only one requirement of adequate donor care. Another is the donor's protection against the systematic and institutional exploitation of his altruistic dispositions. People with the disposition to support those, who are in desperate need, with a nonrenewable part of their own body, despite a small but unavoidable risk of death or health impairment, do not deserve to be additionally burdened with further disincentives, such as financial risks and uncompensated costs of donation. And although the borderline between a morally required disincentive removal and a more controversial net incentive to boost donation might be vague and open to discussion, to disadvantage living donors by design constitutes a serious barrier to the fairness of! living organ donation-a barrier that should be removed. PMID: 20172295 [PubMed - as supplied by publisher] | | |
| Use of Human Umbilical Cord Blood-Derived Progenitor Cells for Tissue-Engineered Heart Valves.
February 23, 2010 at 12:00 PM
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| | Use of Human Umbilical Cord Blood-Derived Progenitor Cells for Tissue-Engineered Heart Valves. Ann Thorac Surg. 2010 Mar;89(3):819-828 Authors: Sodian R, Schaefermeier P, Abegg-Zips S, Kuebler WM, Shakibaei M, Daebritz S, Ziegelmueller J, Schmitz C, Reichart B BACKGROUND: Tissue engineering of autologous heart valves with the potential to grow and to remodel represents a promising concept. Here we describe the use of cryopreserved umbilical cord blood-derived CD133(+) cells as a single cell source for the tissue engineering of heart valves. METHODS: After expansion and differentiation of CD133(+) cells, phenotypes were analyzed by immunohistochemistry and cryopreserved. Heart valve scaffolds fabricated from a biodegradable polymer (n = 8) were seeded with blood-derived myofibroblasts and subsequently coated with blood-derived endothelial cells. Afterward, the heart valve constructs were grown in a pulse duplicator system. Analysis of all heart valves, including histology, immunohistochemistry, electron microscopy, fluorescence imaging, and biochemical and biomechanical examination, was performed. RESULTS: The tissue-engineered heart valves showed endothelialized layered tissue formation including connective tissue betwe! en the inside and the outside of the scaffold. The notion of an intact endothelial phenotype was substantiated by fluorescence imaging studies of cellular nitric oxide production and Ca(2+) signaling. Electron microscopy showed that the cells had grown into the pores and formed a confluent tissue layer. Biochemical examination showed extracellular matrix formation (77% +/- 9% collagen of human pulmonary leaflet tissue [HPLT], 85% +/- 61% glycosaminoglycans of HPLT and 67% +/- 17% elastin of HPLT). CONCLUSIONS: Importantly, this study demonstrates in vitro generation of viable human heart valves based on CD133(+) cells derived from umbilical cord blood. These findings constitute a significant step forward in the development of new clinical strategies for the treatment of congenital defects. PMID: 20172137 [PubMed - as supplied by publisher] | | |
| Combination of small molecules enhances differentiation of mouse embryonic stem cells into intermediate mesoderm through BMP7-positive cells.
February 23, 2010 at 12:00 PM
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| | Combination of small molecules enhances differentiation of mouse embryonic stem cells into intermediate mesoderm through BMP7-positive cells. Biochem Biophys Res Commun. 2010 Feb 18; Authors: Mae SI, Shirasawa S, Yoshie S, Sato F, Kanoh Y, Ichikawa H, Yokoyama T, Yue F, Tomotsune D, Sasaki K Embryonic stem cells (ESCs) are potentially powerful tools for regenerative medicine and establishment of disease models. The recent progress in ESC technologies is noteworthy, but ESC differentiation into renal lineages is relatively less established. The present study aims to differentiate mouse ESCs (mESCs) into a renal progenitor pool, the intermediate mesoderm (IM), without addition of exogenous cytokines and embryoid formation. First, we treated mESCs with a combination of small molecules (Janus-associated tyrosine kinase inhibitor 1, LY294002, and CCG1423) and differentiated them into BMP7-positive cells, BMP7 being the presumed inducing factor for IM. When these cells were cultured with adding retinoic acid, expression of odd-skipped related 1 (Osr1), which is essential to IM differentiation, was enhanced. To simplify the differentiation protocol, the abovementioned 4 small molecules (including retinoic acid) were combined and added to the culture. Under t! his condition, more than one-half of the cells were positive for Osr1, and at the same time, Pax2 (another IM marker) was detected by real-time PCR. Expressions of ectodermal marker and endodermal marker were not enhanced, while mesodermal marker changed. Moreover, expression of genes indispensable to kidney development, i.e., Lim1 and WT1, was detected by RT-PCR. These results indicate the establishment of a specific, effective method for differentiation of the ESC monolayer into IM using a combination of small molecules, resulting in an attractive cell source that could be experimentally differentiated to understand nephrogenic mechanisms and cell-to-cell interactions in embryogenesis. PMID: 20171952 [PubMed - as supplied by publisher] | | |
| Human immune responses to porcine xenogeneic matrices and their extracellular matrix constituents in vitro.
February 23, 2010 at 12:00 PM
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| | Human immune responses to porcine xenogeneic matrices and their extracellular matrix constituents in vitro. Biomaterials. 2010 Feb 18; Authors: Bayrak A, Tyralla M, Ladhoff J, Schleicher M, Stock UA, Volk HD, Seifert M Several tissue engineering approaches for the treatment of cardiovascular diseases are based on a xenogeneic extracellular matrix. However, the application of engineered heart valves has failed in some patients, causing severe signs of inflammation by so far undetermined processes. Therefore we investigated the immune-mediated responses to porcine valve matrices (native, decellularized and glutaraldehyde-fixed) and to purified xenogeneic extracellular matrix proteins (ECMp). The induction of human immune responses in vitro was evaluated by analyzing the co-stimulatory effects of matrices and ECMp collagen and elastin on the proliferation of immune cell sub-populations via CFSE-based proliferation assays. The pattern of cytokine release was also determined. In porcine matrix punches we demonstrated strong immune responses with the native as well as the decellularized type, in contrast to attenuated effects with glutaraldehyde-fixed matrices. Furthermore, our result! s indicate that collagen type I (porcine and human) and human elastin were able to elicit proliferation in co-stimulation with anti-CD3 antibody, accompanied by a strong release of Th1 cytokines (IFN-gamma, TNF-alpha). In contrast, porcine elastin did not elicit any response at all. This low immunogenic potential of porcine elastin suggests its suitability for the creation of new tissue engineering heart valve scaffolds in the future. PMID: 20171732 [PubMed - as supplied by publisher] | | |
| Island Osteoperiosteal Flap for Alveolar Bone Reconstruction.
February 23, 2010 at 12:00 PM
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| | Island Osteoperiosteal Flap for Alveolar Bone Reconstruction. J Oral Maxillofac Surg. 2010 Mar;68(3):539-546 Authors: Jensen OT, Mogyoros R, Owen Z, Cottam JR, Alterman M, Casap N The island osteoperiosteal flap (I-flap) is introduced as a modified alveolar split bone grafting technique used to gain width and modify the facial or buccal bone plate position. Three case examples are shown as well as animal histology indicating the possible development of this new surgical procedure as an adjunct for alveolar augmentation and implant therapy. PMID: 20171473 [PubMed - as supplied by publisher] | | |
| CRTAC1 homolog proteins are conserved from cyanobacteria to man and secreted by the teleost fish pituitary gland.
February 23, 2010 at 12:00 PM
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| | CRTAC1 homolog proteins are conserved from cyanobacteria to man and secreted by the teleost fish pituitary gland. Gene. 2010 Feb 17; Authors: Redruello B, Louro B, Anjos L, Silva N, Greenwell RS, Canario AV, Power DM Cartilage acidic protein 1 (CRTAC1) gene expression is used as a marker for chondrocyte differentiation in stem-cell based tissue engineering. It is also transcribed outside the skeleton where at least two different transcripts are expressed in lung and brain. In the pituitary gland of the teleost fish sea bream Sparus auratus we have found a transcript with a high degree of sequence identity to CRTAC1 family members but lacking the EGF-like calcium binding domain encoding sequence of CRTAC1 and designated it as CRTAC2. Database searches revealed many previously unidentified members of the CRTAC1 and CRTAC2 in phylogenetically distant organisms, such as cyanobacteria, bryophyta, lancelets and diverse representatives of vertebrates. Phylogenetic analyses showed that the genes encoding CRTAC1 and CRTAC2 proteins co-exist in teleost fish genomes. Structural prediction analysis identified the N-terminal region of the CRTAC1/CRTAC2 family members as a potential seven b! laded beta-propeller structure, closely related to those of integrin alpha chains and glycosylphosphatidylinositol specific phospholipase D1 protein families. This relationship is confirmed by phylogenetic analysis with the N-terminal domain of sea bream CRTAC2 as the most divergent sequence. Since teleost fishes are the only phylogenetic group where both CRTAC1 and CRTAC2 genes are present, they occupy a pivotal position in studies of the mechanisms governing the specific expression patterns of each gene/protein subfamily. This will be essential to elucidate their respective biological roles. PMID: 20171266 [PubMed - as supplied by publisher] | | |
| In vitro non-viral lipofectamine delivery of the gene for glial cell line-derived neurotrophic factor to human umbilical cord blood CD34+ cells.
February 23, 2010 at 12:00 PM
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| | In vitro non-viral lipofectamine delivery of the gene for glial cell line-derived neurotrophic factor to human umbilical cord blood CD34+ cells. Brain Res. 2010 Feb 17; Authors: Yu G, Borlongan CV, Ou Y, Stahl CE, Yu S, Bae E, Kaneko Y, Yang T, Yuan C, Fang L Using a lipofection technique, we explored a non-viral delivery of plasmid DNA encoding a rat pGDNF (glial cell line-derived neurotrophic factor) to CD34+ cells derived from human umbilical cord blood (HUCB) cells in order to obtain cells stably expressing the GDNF gene. The target gene GDNF was amplified from cortex cells of newborn Sprague Dawley rats by reverse-transcriptase polymerase chain reaction (RT-PCR) and inserted into vector pEGFP-N1 to construct the eukaryotic expression vector pEGFP/GDNF. The positive clones were identified by sequencing and endonuclease digestion. The expression of pEGFP/GDNF transfected HUCB cells CD34+ was examined by ELISA. Single fragment of 640bp was obtained after the rat GDNF cDNA was amplified by RT-PCR. Two fragments of about 4.3kb and 640pb were obtained after digestion of recombinant plasmid pEGFP/GDNF with XhoI/KpnI. The nucleic acid fragment of 640bp was confirmed to agree well with the sequence of GDNF gene published b! y GeneBank. The expression of GDNF mRNA and the level of GDNF from pEGFP/GDNF-transfected CD34+ cells were increased substantially, compared with pEGFP control plasmid transfected CD34+ cells (P<0.05). Moreover, co-culture of primary rat cells with the pEGFP/GDNF-transfected CD34+ cells promoted enhanced neuropotection against oxygen-glucose deprivation induced cell dysfunctions. The present results support the use of the non-viral plasmid liposome for therapeutic gene expression for stem cell therapy. PMID: 20171195 [PubMed - as supplied by publisher] | | |
| In vivo engineering of a functional tendon sheath in a hen model.
February 23, 2010 at 12:00 PM
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| | In vivo engineering of a functional tendon sheath in a hen model. Biomaterials. 2010 Feb 17; Authors: Xu L, Cao D, Liu W, Zhou G, Zhang WJ, Cao Y Repair of injured tendon sheath remains a major challenge and this study explored the possibility of in vivo reconstruction of a tendon sheath with tendon sheath derived cells and polyglycolic acid (PGA) fibers in a Leghorn hen model. Total 55 Leghorn hens with a 1cm tendon sheath defect created in the left middle toe of each animal were randomly assigned into: (1) experimental group (n=19) that received a cell-PGA construct; (2) scaffold control group (n=18) that received a cell-free PGA scaffold; (3) blank control group (n=18) with the defect untreated. Tendon sheath cells were isolated, in vitro expanded, and seeded onto PGA scaffolds. After in vitro culture for 7 days, the constructs were in vivo implanted to repair the sheath defects. Alcian blue staining confirmed the ability of cultured cells to produce specific matrices containing acidic carboxyl mucopolysaccharide (mainly hyaluronic acid). In addition, the engineered sheath formed a relatively mature stru! cture at 12 weeks post-surgery, which was similar to that of native counterpart, including a smooth inner surface, a well-developed sheath histological structure with a clear space between the tendon and the engineered sheath. More importantly, Work of Flexion assay revealed that the tendons needed less power consumption to glide inside the engineered sheath when compared to the tendons which were surrounded by scar-repaired tissues, indicating that the engineered sheaths had gained the function to a certain extent of preventing tendon adhesion. Taken together, these results suggest that tendon sheaths that are functionally and structurally similar to native sheaths are possible to be engineered in vivo using tendon sheath cells and PGA scaffolds. PMID: 20170958 [PubMed - as supplied by publisher] | | |
| Pre-vascularization of in vitro three-dimensional tissues created by cell sheet engineering.
February 23, 2010 at 12:00 PM
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| | Pre-vascularization of in vitro three-dimensional tissues created by cell sheet engineering. Biomaterials. 2010 Feb 17; Authors: Asakawa N, Shimizu T, Tsuda Y, Sekiya S, Sasagawa T, Yamato M, Fukai F, Okano T Reconstructing a vascular network is a common task for three-dimensional (3-D) tissue engineering. Three-dimensional stratified tissues were created by stacking cell sheets, and the co-culture with endothelial cells (ECs) in the tissues was found to lead to in vitro pre-vascular network formation and promoted in vivo neovascularization after their transplantation. In this study, to clarify the effect of tissue fabrication process on a pre-vascular network formation, human origin ECs were introduced into the stratified tissue in several different ways, and the behavior of ECs in various positions of the 3-D tissue were compared each other. Human umbilical vein endothelial cells (HUVECs), normal human dermal fibroblasts (NHDFs), and their mixture were harvested as an intact cell sheet from temperature-responsive culture dish at low-temperature (<20 degrees C). Single mono-culture EC sheet was stacked with two NHDF-sheets in different orders, and 3 co-cultured cel! l sheets were layered by a cell sheet collecting device. Morphological analyses revealed that pre-vascular networks composing of HUVECs were formed in all the triple layer constructs. Confocal microscope observation showed that the pre-vascular networks formed tube structures like a native microvasculature. These data indicate that the primary EC positioning in 3-D tissues may be critical for vascular formation. PMID: 20170957 [PubMed - as supplied by publisher] | | |
| Thermogelling chitosan and collagen composite hydrogels initiated with beta-glycerophosphate for bone tissue engineering.
February 23, 2010 at 12:00 PM
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| | Thermogelling chitosan and collagen composite hydrogels initiated with beta-glycerophosphate for bone tissue engineering. Biomaterials. 2010 Feb 17; Authors: Wang L, Stegemann JP Chitosan and collagen type I are naturally derived materials used as cell carriers because of their ability to mimic the extracellular environment and direct cell function. In this study beta-glycerophosphate (beta-GP), an osteogenic medium supplement and a weak base, was used to simultaneously initiate gelation of pure chitosan, pure collagen, and chitosan-collagen composite materials at physiological pH and temperature. Adult human bone marrow-derived stem cells (hBMSC) encapsulated in such hydrogels at chitosan/collagen ratios of 100/0, 65/35, 25/75, and 0/100wt% exhibited high viability at day 1 after encapsulation, but DNA content dropped by about half over 12 days in pure chitosan materials while it increased twofold in materials containing collagen. Collagen-containing materials compacted more strongly and were significantly stiffer than pure chitosan gels. In monolayer culture, exposure of hBMSC to beta-GP resulted in decreased cell metabolic activity that! varied with concentration and exposure time, but washing effectively removed excess beta-GP from hydrogels. The presence of chitosan in materials resulted in higher expression of osterix and bone sialoprotein genes in medium with and without osteogenic supplements. Chitosan also increased alkaline phosphatase activity and calcium deposition in osteogenic medium. Chitosan-collagen composite materials have potential as matrices for cell encapsulation and delivery, or as in situ gel-forming materials for tissue repair. PMID: 20170955 [PubMed - as supplied by publisher] | | |
| Intra-uterine tissue engineering of full-thickness skin defects in a fetal sheep model.
February 23, 2010 at 12:00 PM
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| | Intra-uterine tissue engineering of full-thickness skin defects in a fetal sheep model. Biomaterials. 2010 Feb 17; Authors: Hosper NA, Eggink AJ, Roelofs LA, Wijnen RM, van Luyn MJ, Bank RA, Harmsen MC, Geutjes PJ, Daamen WF, van Kuppevelt TH, Tiemessen DM, Oosterwijk E, Crevels JJ, Blokx WA, Lotgering FK, van den Berg PP, Feitz WF In spina bifida the neural tube fails to close during the embryonic period and it is thought that prolonged exposure of the unprotected spinal cord to the amniotic fluid during pregnancy causes additional neural damage. Intra-uterine repair might protect the neural tissue from exposure to amniotic fluid and might reduce additional neural damage. Biodegradable collagen scaffolds may be useful in case of fetal therapy for spina bifida, but biochemical properties need to be studied. The aim of this study was to investigate whether biodegradable collagen scaffolds can be used to treat full-thickness fetal skin defects. We hypothesized that the pro-angiogenic growth factors VEGF and FGF2 would enhance vascularization, epidermialization and lead to improved wound healing. To investigate the effect of these two growth factors, a fetal sheep model for skin defects was used. Compared to wounds treated with bare collagen scaffolds, wounds treated with growth factor-loaded s! caffolds showed excessive formation of capillaries and less myofibroblasts were present in these wounds, leading to less contraction. This study has demonstrated that collagen scaffolds can be used to treat fetal skin defects and that the combination of collagen scaffolds with VEGF and FGF2 had a beneficial effect on wound healing. PMID: 20170954 [PubMed - as supplied by publisher] | | |
| Enzymatically degradable poly(ethylene glycol) based hydrogels for adipose tissue engineering.
February 23, 2010 at 12:00 PM
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| | Enzymatically degradable poly(ethylene glycol) based hydrogels for adipose tissue engineering. Biomaterials. 2010 Feb 17; Authors: Brandl FP, Seitz AK, Teßmar JK, Blunk T, Göpferich AM Adipose tissue engineering requires biomaterials that promote the differentiation of seeded adipocytes. Here, we report on the development and characterization of in situ forming, poly(ethylene glycol) (PEG) based hydrogels for soft tissue augmentation. Branched PEG-amines were modified with collagenase-sensitive peptides and cross-linked with branched PEG-succinimidyl propionates without the use of free-radical initiators (enzymatically degradable hydrogels). Alanine-modified PEG-amines were used for the preparation of non-degradable gels. Depending on the used polymer concentration, the strength of degradable gels after swelling ranged from 1708 to 7412Pa; the strength of non-degradable hydrogels varied between 1496 and 7686Pa. Enzyme mediated gel degradation occurred within 10, 16, and 19 days (5%, 10%, and 15% initial polymer content). To evaluate their suitability as scaffold materials for adipose tissue engineering, the hydrogels were functionalized with the! laminin-derived adhesion peptide YIGSR, and seeded with 3T3-L1 preadipocytes. Compared to a standard two-dimensional cell culture model, the developed hydrogels significantly enhanced the intracellular triglyceride accumulation of encapsulated adipocytes. Functionalization with YIGSR further enhanced lipid synthesis within differentiating adipocytes. Long-term studies suggested that enzymatically degradable hydrogels furthermore promote the formation of coherent adipose tissue-like structures featuring many mature unilocular fat cells. PMID: 20170951 [PubMed - as supplied by publisher] | | |
| Influences of Tensile Load on in vitro Degradation of Electrospun Poly(L-Lactide-co-Glycolide) Scaffold.
February 23, 2010 at 12:00 PM
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| | Influences of Tensile Load on in vitro Degradation of Electrospun Poly(L-Lactide-co-Glycolide) Scaffold. Acta Biomater. 2010 Feb 16; Authors: Li P, Feng X, Jia X, Fan Y The scaffolds for tissue engineering, regenerative medicine and implantation are usually subjected to different mechanical loads during invitro or in vivo degradation. In this study, invitro degradation procedures of electrospun poly(L-lactide-co-glycolide) (PLGA) scaffolds were examined under continuous tensile load in comparison with that under no load. While PLGA degraded in phosphate buffered saline solution (pH, 7.4) at 37 degrees C over a 7-week period, the tensile elastic modulus and ultimate strength of loaded specimen increased dramatically, then followed by a decreasing tendency which was much faster than that of unloaded, whereas the break elongation of loaded ones declined quicker during the whole degradation time. Moreover, changes in molecular weight, thermal properties and lactic acid release showed a more remarkable degradation behavior under load. And the ruptured morphologies were more obvious after degradation under tensile load. The results dem! onstrated that the tensile load increased the degradation rate of electrospun PLGA and it may be highly necessary to consider the effect of mechanical load when designing or applying the biodegradable scaffold. Finally, some possible explanations to the faster degradation under load were given. PMID: 20170760 [PubMed - as supplied by publisher] | | |
| Development of a porcine bladder acellular matrix with well preserved extracellular bioactive factors for tissue engineering.
February 23, 2010 at 12:00 PM
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| | Development of a porcine bladder acellular matrix with well preserved extracellular bioactive factors for tissue engineering. Tissue Eng Part C Methods. 2010 Feb 22; Authors: Yang B, Zhang Y, Zhou LH, Sun ZY, Zheng JH, Chen Y, Dai YT In this study, we compared four decellularization protocols and finally developed an optimized one through which a porcine bladder acellular matrix (BAM) with well preserved extracellular bioactive factors had been prepared. In this protocol, the intact bladder was treated with trypsin/EDTA to remove the urothelium, then with hypotonic buffer and Triton X-100 in hypertonic buffer to remove the membranous and cytoplasmic materials and finally with nuclease to degrade the cellular nuclear components. Bladder distention and mechanical agitation were simultaneously used to facilitate cell removal. Meanwhile, several preservative techniques, including limitation of wash time, supplement with inhibitors of proteinase, control of the pH value and temperature of the wash buffer, ethylene oxide sterilization and lyophilization of the scaffold for storage, were used to protect the extracellular bioactive factors. This decellularization protocol had completely removed the ce! llular materials and well preserved the extracellular collagen, sulfated glycosaminoglycan (GAG) and bioactive factors. The preserved bioactive factors had a great potential of promoting the proliferation and migration of both human bladder smooth muscle cell and human umbilical vein endothelial cell. It was also found that the amount of two representative bioactive factors, platelet-derived growth factor BB (PDGF-BB) and vascular endothelial growth factor (VEGF), was positively correlated with the sulfated GAG content in the porcine BAM, implying that the amount of sulfated GAG might be a determinant for preservation of bioactive factors in the decellularized tissues. In conclusion, the porcine BAM with well preserved extracellular bioactive factors might be a favorable scaffold for tissue engineering applications. PMID: 20170425 [PubMed - as supplied by publisher] | | |
| The influence of rat mesenchymal stem cell CD44 surface markers on cell growth, fibronectin expression, and cardiomyogenic differentiation on silk fibroin - Hyaluronic acid cardiac patches.
February 23, 2010 at 12:00 PM
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| | The influence of rat mesenchymal stem cell CD44 surface markers on cell growth, fibronectin expression, and cardiomyogenic differentiation on silk fibroin - Hyaluronic acid cardiac patches. Biomaterials. 2010 Feb;31(5):854-62 Authors: Yang MC, Chi NH, Chou NK, Huang YY, Chung TW, Chang YL, Liu HC, Shieh MJ, Wang SS Since MSCs contain an abundant of CD44 surface markers, it is of interesting to investigate whether CD44 on rat MSC (rMSCs) influenced cell growth, fibronectin expression and cardiomyogenic differentiation on new SF/HA cardiac patches. For this investigation, we examined the influences of rMSCs with or without a CD44-blockage treatment on the aforementioned issues after they were cultivated, and further induced by 5-aza on SF and SF/HA patches. The results showed that the relative growth rates of rMSCs cultured on cultural wells, SF/HA patches without or with a CD44-blockage treatment were 100%, 208.9+/-7.1 (%) or 48.4+/-6.0 (%) (n=3, for all), respectively, after five days of cultivations. Moreover, rMSCs cultivated on SF/HA patches highly promoted fibronectin expressions (e.g., 1.8x10(5)/cell, in fluorescent intensity) while cells with a CD44-blockage treatment markedly diminished the expressions (e.g., 1.1x10(4)/cell, in fluorescent intensity) on same patches. ! For investigating possible influences of CD44 surface markers of rMSCs on their cardiomyogenic differentiation, the expressions of specific cardiac genes of cells were examined by using real-time PCR analysis. The results indicated that 5-aza inducing rMSCs significantly promoted the expressions of Gata4, Nkx2.5, Tnnt2 and Actc1 genes (all, P<0.01 or better, n=3) on SF/HA patches compared with those expressions on SF patches and for cells with a CD44-blockage treatment on SF/HA patches. Furthermore, the intensity of the expressions of cardiotin and connexin 43 of 5-aza inducing rMSCs were markedly higher than those of cells with a CD44-blockage treatment after they were cultured on SF/HA patches. Through this study, we reported that CD44 surface markers of rMSCs highly influenced the proliferations, fibronectin expressions and cardiomyogenic differentiation of rMSCs cultivated on cardiac SF/HA patches. PMID: 19857893 [PubMed - indexed for MEDLINE] | | |
| Plant polyphenols and tumors: from mechanisms to therapies, prevention, and protection against toxicity of anti-cancer treatments.
February 23, 2010 at 12:00 PM
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| | Plant polyphenols and tumors: from mechanisms to therapies, prevention, and protection against toxicity of anti-cancer treatments. Curr Med Chem. 2009;16(30):3943-65 Authors: Korkina LG, De Luca C, Kostyuk VA, Pastore S Polyphenolic molecules produced by higher plants in response to biotic and abiotic stresses exert numerous effects on tumorigenic cell transformation, and on tumor cells in vitro and in vivo, and may interact with conventional anti-tumor therapies. In the present review, we collected and critically discussed data on: (i) redox-dependent and redox-independent mechanisms underlying cytotoxic/cytostatic effects of PPs and their metabolites towards tumor cells and cytoprotection of normal cells; (ii) mechanisms of anti-angiogenic and anti-metastatic action of PPs; (iii) PPs-associated phototoxicity against tumor cells and photoprotection of non-tumor cells; (iv) PPs effects on drug-metabolizing enzymes as a basis for their synergism or antagonism with chemotherapy; (v) molecular pathways leading to tumor chemoprevention by PPs; and (vi) PPs as protectors against toxic effects of chemo-, radio-, and photodynamic therapies. PMID: 19747130 [PubMed - indexed for MEDLINE] | | |
| Nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP offered as cell substrate: spacing determines attachment and differentiation of neurons.
February 23, 2010 at 12:00 PM
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| | Nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP offered as cell substrate: spacing determines attachment and differentiation of neurons. Nano Lett. 2009 Dec;9(12):4115-21 Authors: Jaehrling S, Thelen K, Wolfram T, Pollerberg GE The density/spacing of plasma membrane proteins is thought to be crucial for their function; clear-cut experimental evidence, however, is still rare. We examined nanopatterns biofunctionalized with cell adhesion molecule DM-GRASP with respect to their impact on neuron attachment and neurite growth. Data analysis/modeling revealed that these cellular responses improve with increasing DM-GRASP density, with the exception of one spacing which does not allow for the anchorage of a cytoskeletal protein (spectrin) to three DM-GRASP molecules. PMID: 19694460 [PubMed - indexed for MEDLINE] | | |
| Application of polyethyleneimine-modified scaffolds to the regeneration of cartilaginous tissue.
February 23, 2010 at 12:00 PM
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| | Application of polyethyleneimine-modified scaffolds to the regeneration of cartilaginous tissue. Biotechnol Prog. 2009 Sep-Oct;25(5):1459-67 Authors: Kuo YC, Ku IN In this study, we analyzed the physicochemical and biophysical properties of three-dimensional scaffolds modified using polyethyleneimine (PEI) and applied these scaffolds to the cultivation of bovine knee chondrocytes (BKCs). PEI was crosslinked in the bulk or on the surface of the ternary scaffolds comprising polyethylene oxide, chitin and chitosan. The results revealed that when the concentration of PEI was less than 300 microg/mL, the cytotoxicity of a scaffold was on the same order in the two method of modification. An increase in the concentration of PEI favored the adhesion of BKCs. When the amount of PEI in scaffolds is fixed, the surface-modified scaffolds exhibited a higher adhesion efficiency of BKCs than the bulk-modified scaffolds. For the regeneration of cartilaginous components, a higher amount of PEI in a scaffold yielded larger amounts of proliferated BKCs, secreted glycosaminoglycans, and produced collagen. In addition, the formation of neocartil! age in the surface-modified scaffolds was more effective than that in the bulk-modified scaffolds. These tissue-engineered scaffolds, modified by an appropriate concentration of PEI, can be potentially applied to cartilage repair in clinical trials. PMID: 19637393 [PubMed - indexed for MEDLINE] | | |
| Development of bioactive peptide amphiphiles for therapeutic cell delivery.
February 23, 2010 at 12:00 PM
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| | Development of bioactive peptide amphiphiles for therapeutic cell delivery. Acta Biomater. 2010 Jan;6(1):3-11 Authors: Webber MJ, Tongers J, Renault MA, Roncalli JG, Losordo DW, Stupp SI There is great clinical interest in cell-based therapies for ischemic tissue repair in cardiovascular disease. However, the regenerative potential of these therapies is limited due to poor cell viability and minimal retention following application. We report here the development of bioactive peptide amphiphile nanofibers displaying the fibronectin-derived RGDS cell adhesion epitope as a scaffold for therapeutic delivery of bone marrow derived stem and progenitor cells. When grown on flat substrates, a binary peptide amphiphile system consisting of 10 wt.% RGDS-containing molecules and 90wt.% negatively charged diluent molecules was found to promote optimal cell adhesion. This binary system enhanced adhesion 1.4-fold relative to substrates composed of only the non-bioactive diluent. Additionally, no enhancement was found upon scrambling the epitope and adhesion was no longer enhanced upon adding soluble RGDS to the cell media, indicating RGDS-specific adhesion. Whe! n encapsulated within self-assembled scaffolds of the binary RGDS nanofibers in vitro, cells were found to be viable and proliferative, increasing in number by 5.5 times after only 5 days, an effect again lost upon adding soluble RGDS. Cells encapsulated within a non-bioactive scaffold and those within a binary scaffold with scrambled epitope showed minimal viability and no proliferation. Cells encapsulated within this RGDS nanofiber gel also increase in endothelial character, evident by a decrease in the expression of CD34 paired with an increase in the expression of endothelial-specific markers VE-Cadherin, VEGFR2 and eNOS after 5 days. In an in vivo study, nanofibers and luciferase-expressing cells were co-injected subcutaneously in a mouse model. The binary RGDS material supported these cells in vivo, evident by a 3.2-fold increase in bioluminescent signal attributable to viable cells; this suggests the material has an anti-apoptotic and/or proliferative effect on the t! ransplanted bone marrow cells. We conclude that the binary RGD! S-presen ting nanofibers developed here demonstrate enhanced viability, proliferation and adhesion of associated bone marrow derived stem and progenitor cells. This study suggests potential for this material as a scaffold to overcome current limitations of stem cell therapies for ischemic diseases. PMID: 19635599 [PubMed - indexed for MEDLINE] | | |
| Spatial organization of osteoblast fibronectin matrix on titanium surfaces: effects of roughness, chemical heterogeneity and surface energy.
February 23, 2010 at 12:00 PM
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| | Spatial organization of osteoblast fibronectin matrix on titanium surfaces: effects of roughness, chemical heterogeneity and surface energy. Acta Biomater. 2010 Jan;6(1):291-301 Authors: Pegueroles M, Aparicio C, Bosio M, Engel E, Gil FJ, Planell JA, Altankov G We investigated the early events of bone matrix formation, and specifically the role of fibronectin (FN) in the initial osteoblast interaction and the subsequent organization of a provisional FN matrix on different rough titanium (Ti) surfaces. Fluorescein isothiocyanate-labelled FN was preadsorbed on these surfaces and studied for its three-dimensional (3-D) organization by confocal microscopy, while its amount was quantified after NaOH extraction. An irregular pattern of adsorption with a higher amount of protein on topographic peaks than on valleys was observed and attributed to the physicochemical heterogeneity of the rough Ti surfaces. MG63 osteoblast-like cells were further cultured on FN-preadsorbed Ti surfaces and an improved initial cellular interaction was observed with increasing roughness. 3-D reconstruction of the immunofluorescence images after 4 days of incubation revealed that osteoblasts deposit FN fibrils in a specific facet-like pattern that is ! organized within the secreted total matrix overlying the top of the samples. The thickness of this FN layer increased when the roughness of the underlying topography was increased, but not by more than half of the total maximum peak-to-valley distance, as demonstrated with images showing simultaneous reconstruction of fluorescence and topography after 7 days of cell culture. PMID: 19635598 [PubMed - indexed for MEDLINE] | | |
| Collagen and glycopolymer based hydrogel for potential corneal application.
February 23, 2010 at 12:00 PM
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| | Collagen and glycopolymer based hydrogel for potential corneal application. Acta Biomater. 2010 Jan;6(1):187-94 Authors: Deng C, Li F, Hackett JM, Chaudhry SH, Toll FN, Toye B, Hodge W, Griffith M 6-Methacryloyl-alpha-D-galactopyranose (MG) was synthesized, and characterized by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectrometry, and single-crystal X-ray diffraction. A series of interpenetrating polymer network (IPN) hydrogels was fabricated by simultaneously photocuring MG crosslinked by poly(ethylene glycol) diacrylate and chemically crosslinking type I collagen with 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide. The successful incorporation of the glycopolymer, polymer MG, into collagen hydrogel was confirmed by FTIR and solid-state (13)C NMR. The optical characteristics of the IPN hydrogels are comparable to those of human corneas. The tensile strength and modulus of the hydrogels are enhanced by incorporation of polymer MG in comparison to that of the control collagen hydrogel. Biodegradation results indicated that polymer MG enhanced the stability of the composite hydrogels against collagenase.! In vitro results demonstrated that the IPN hydrogel supported the adhesion and proliferation of human corneal epithelial cells and outperformed human cornea in blocking bacteria adhesion. Taken together, the IPN hydrogel might be a promising material for use in corneal lamellar keratoplasty. PMID: 19632359 [PubMed - indexed for MEDLINE] | | |
| Repair of full-thickness femoral condyle cartilage defects using allogeneic synovial cell-engineered tissue constructs.
February 23, 2010 at 12:00 PM
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| | Repair of full-thickness femoral condyle cartilage defects using allogeneic synovial cell-engineered tissue constructs. Osteoarthritis Cartilage. 2009 Jun;17(6):714-22 Authors: Pei M, He F, Boyce BM, Kish VL OBJECTIVE: Synovium-derived stem cells (SDSCs) have proven to be superior in cartilage regeneration compared with other sources of mesenchymal stem cells. We hypothesized that conventionally passaged SDSCs can be engineered in vitro into cartilage tissue constructs and the engineered premature tissue can be implanted to repair allogeneic full-thickness femoral condyle cartilage defects without immune rejection. METHODS: Synovial tissue was harvested from rabbit knee joints. Passage 3 SDSCs were mixed with fibrin glue and seeded into non-woven polyglycolic acid (PGA) mesh. After 1-month incubation with growth factor cocktails, the premature tissue was implanted into rabbit knees to repair osteochondral defects with Collagraft as a bone substitute in the Construct group. Fibrin glue-saturated PGA/Collagraft composites were used as a Scaffold group. The defect was left untreated as an Empty group. RESULTS: SDSCs were engineered in rotating bioreactor systems into pre! mature cartilage, which displayed the expression of sulfated glycosaminoglycan (GAG), collagen II, collagen I, and macrophages. Six months after implantation with premature tissue, cartilage defects were full of smooth hyaline-like cartilage with no detectable collagen I and macrophages but a high expression of collagen II and GAG, which were also integrated with the surrounding native cartilage. The Scaffold and Empty groups were resurfaced with fibrous-like and fibrocartilage tissue, respectively. CONCLUSION: Allogeneic SDSC-based premature tissue constructs are a promising stem cell-based approach for cartilage defects. Although in vitro data suggest that contaminated macrophages affected the quality of SDSC-based premature cartilage, effects of macrophages on in vivo tissue regeneration and integration necessitate further investigation. PMID: 19128988 [PubMed - indexed for MEDLINE] | | | | 
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