| Experimental Biology set for April 2010
January 8, 2010 at 4:43 pm
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| Advanced Cell Technology Provides Update on Clinical Trials Using Embryonic Stem Cells to Treat Eye Disease
January 8, 2010 at 8:42 am
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| International Stem Cell Corporation to Present at Multiple Near-Term Events
January 8, 2010 at 8:42 am
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| 5th Annual Summit to Feature New Stem Cell Therapies
January 8, 2010 at 7:42 am
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| Mesenchymal stem cells do not suppress lymphoblastic leukemic cell line proliferation.
January 8, 2010 at 6:53 am
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| | Mesenchymal stem cells do not suppress lymphoblastic leukemic cell line proliferation. Iran J Immunol. 2009 Dec;6(4):186-94 Authors: Mousavi Niri N, Jaberipour M, Razmkhah M, Ghaderi A, Habibagahi M Background: Several studies have demonstrated the immunosuppresive effects of mesenchymal stem cells (MSCs) in allogeneic or mitogenic interactions. Cell-cell contact inhibition and secretion of suppressive soluble factors have been suggested in this regard. Objective: To investigate if adipose derived MSCs could inhibit Jurkat lymphoblastic leukemia T cell proliferation during coculture. Methods: Adherent cells with the ability of cellular growth were isolated from normal adipose tissues. Initial characterization of growing cells by flow cytometry suggested their mesenchymal stem cell characteristics. Cells were maintained in culture and used during third to fifth culture passages. Jurkat or allogeneic peripheral blood mononuclear cells (PBMCs) were labeled with carboxy fluorescein diacetate succinimidyl ester and cocultured with increasing doses of MSCs or MSC culture supernatant. Proliferation of PBMCs or Jurkat cells under these conditions was assessed by flow cytometry after 2 and 3 days of coculture, respectively. Results: Results showed the expression of CD105, CD166 and CD44, and the absence of CD45, CD34 and CD14 on the surface of MSC like cells. Moreover, initial differentiation studies showed the potential of cell differentiation into hepatocytes. Comparison of Jurkat cell proliferation in the presence and absence of MSCs showed no significant difference, with 70% of cells displaying signs of at least one cell division. Similarly, the highest concentration of MSC culture supernatant (50% vol/vol) had no significant effect on Jurkat cell proliferation (p>0.6). The same MSC lots significantly suppressed the allogeneic PHA activated PBMCs under similar culture conditions. Conclusion: Using Jurkat cells as a model of leukemia T cells, our results indicated an uncertainty about the suppressive effect of MSCs and their inhibitory metabolites on tumor or leukemia cell proliferation. Additional systematic studies with MSCs of different sources are needed to fully characterize the immunological properties of MSCs before planning clinical applications. PMID: 20054106 [PubMed - in process] |
| [Stem cell-based therapy in central nervous system diseases.]
January 8, 2010 at 6:52 am
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| | [Stem cell-based therapy in central nervous system diseases.] Neurol Neurochir Pol. 2009 Nov-Dec;43(6):550-8 Authors: Paczkowska E, Dabkowska E, Nowacki P, Machaliński B Much of the current research into stem cell biology is focused on its potential for regeneration of various tissues and organs. Stem cell-based therapy with autologous bone marrow stem cells could provide an attractive alternative to the classical therapeutic approach in the foreseeable future. The possibility of nervous tissue regeneration in neurodegenerative disorders of the central nervous system generates a special challenge for researchers and clinicians involved in that field of medicine. Very small embryonic-like stem cells (VSEL SCs), recently discovered in murine bone marrow and human umbilical cord blood, arouse great hope. VSEL SCs display several features typical for embryonic stem cells, such as a large nucleus surrounded by a narrow rim of cytoplasm, euchromatin, and expression of pluripotent markers (Oct-4, Nanog, SSEA-4). Application of these cells in regenerative medicine could have considerable advantages over strategies using embryonic stem cells, since ethical concerns might be naturally solved. Thus, these cells can become a recommended source of stem cells for cell therapy as compared to those isolated from developing embryos. PMID: 20054758 [PubMed - in process] |
| Collagen Glycation Alters Neovascularization in vitro and in vivo.
January 8, 2010 at 6:52 am
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| | Collagen Glycation Alters Neovascularization in vitro and in vivo. Microvasc Res. 2010 Jan 3; Authors: Francis-Sedlak ME, Moya ML, Huang JJ, Lucas SA, Chandrasekharan N, Larson JC, Cheng MH, Brey EM Microvascular network formation is required for the success of many therapies in regenerative medicine. The process of vessel assembly is fundamentally altered, however, in many people within the potential patient population, including the elderly and people with diabetes. Significant research has been performed to determine how cellular dysfunction contributes to this inadequate neovascularization, but alterations in the extracellular matrix (ECM) may also influence this process. Glycation of ECM proteins, specifically type I collagen, increases as people age and is accelerated due to uncontrolled diabetes. This glycation results in increased ECM stiffness and resistance to degradation. The goal of this research is to determine whether collagen glycation consistent with changes in aged (defined as people greater than 80 years old) and diabetic individuals influences neovascularization. Collagen gels that were incubated in glucose-6-phopshate (G6P) for varying times exhibited crosslinking (26.2 +/- 8.1% and 31.3 +/- 5.6% for incubation in 375mM G6P for 5 and 8 days, respectively), autofluorescence and advanced glycation end product levels (666 +/- 481 and 2122 +/- 501 pmol/mg protein for 5 and 8 days of 375mM G6P, respectively) consistent with aged and diabetic populations. Three-dimensional culture models showed that sprouting angiogenesis was delayed in collagen gels with high levels of glycation. When implanted in vivo, glycated gels were degraded (44.4 +/- 4.2% and 49.5 +/- 11.7% non-degraded gel remaining for gels incubated for 5 and 8 days in 375mM G6P, respectively) and vascularized (75.5 +/- 32.0 and 73.7 +/- 23.6 vessels/mm(2)) more slowly than controls (22.3 +/- 9.9% gel remaining and 133.3 +/- 31.0 vessels/mm(2)). These results suggest that glycation of collagen can alter neovascularization and may contribute to alterations in vessel assembly observed as people age and due to diabetes. PMID: 20053366 [PubMed - as supplied by publisher] |
| Cell Culture on MEMS Platforms: A Review.
January 8, 2010 at 6:11 am
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| | Cell Culture on MEMS Platforms: A Review. Int J Mol Sci. 2009 Dec;10(12):5411-41 Authors: Ni M, Tong WH, Choudhury D, Rahim NA, Iliescu C, Yu H Microfabricated systems provide an excellent platform for the culture of cells, and are an extremely useful tool for the investigation of cellular responses to various stimuli. Advantages offered over traditional methods include cost-effectiveness, controllability, low volume, high resolution, and sensitivity. Both biocompatible and bio-incompatible materials have been developed for use in these applications. Biocompatible materials such as PMMA or PLGA can be used directly for cell culture. However, for bio-incompatible materials such as silicon or PDMS, additional steps need to be taken to render these materials more suitable for cell adhesion and maintenance. This review describes multiple surface modification strategies to improve the biocompatibility of MEMS materials. Basic concepts of cell-biomaterial interactions, such as protein adsorption and cell adhesion are covered. Finally, the applications of these MEMS materials in Tissue Engineering are presented. PMID: 20054478 [PubMed - in process] |
| The effect of unlocking RGD-motifs in collagen I on pre-osteoblast adhesion and differentiation.
January 8, 2010 at 6:11 am
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| | The effect of unlocking RGD-motifs in collagen I on pre-osteoblast adhesion and differentiation. Biomaterials. 2010 Jan 4; Authors: Taubenberger AV, Woodruff MA, Bai H, Muller DJ, Hutmacher DW Denaturation of extracellular matrix proteins exposes cryptic binding sites. It is hypothesized that binding of cell adhesion receptors to these cryptic binding sites regulates cellular behaviour during tissue repair and regeneration. To test this hypothesis, we quantify the adhesion of pre-osteoblastic cells to native (Col) and partially-denatured (pdCol) collagen I using single-cell force spectroscopy. During early stages of cell attachment (</=180 s) pre-osteoblasts (MC3T3-E1) adhered significantly stronger to pdCol compared to Col. RGD (Arg-Gly-Asp)-containing peptides suppressed this elevated cell adhesion. We show that the RGD-binding alpha(5)beta(1)- and alpha(v)-integrins mediated pre-osteoblast adhesion to pdCol, but not to Col. On pdCol pre-osteoblasts had a higher focal adhesion kinase tyrosine-phosphorylation level that correlated with enhanced spreading and motility. Moreover, pre-osteoblasts cultured on pdCol showed a pronounced matrix mineralization activity. Our data suggest that partially-denatured collagen exposes RGD-motifs that trigger binding of alpha(5)beta(1)- and alpha(v)-integrins. These integrins initiate cellular processes that stimulate osteoblast adhesion, spreading, motility and differentiation. Taken together, these quantitative insights reveal an approach for the development of alternative collagen I- based surfaces for tissue engineering applications. PMID: 20053443 [PubMed - as supplied by publisher] |
| Role of the microenvironment in the specification of endothelial progenitors derived from embryonic stem cells.
January 8, 2010 at 6:11 am
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| | Role of the microenvironment in the specification of endothelial progenitors derived from embryonic stem cells. Microvasc Res. 2010 Jan 3; Authors: Noghero A, Bussolino F, Gualandris A Embryonic stem (ES) cells are pluripotent cells capable of differentiating in all the cell types present in a living organism. They derive from the inner cell mass of blastocysts of different species including humans. Given their unlimited potential, ES cells represent an invaluable resource of different cell types for transplantation and tissue engineering applications. However, in order to accomplish these therapeutic purposes, efficient and controlled in vitro systems of directing ES cells differentiation are mandatory. ES cells differentiation is strongly influenced by physical, chemical and cellular signals provided by the local microenvironment. Understanding the relationships occurring between differentiating cells and surrounding environment is pivotal for a successful ES cells-based therapy. This review describes three different methods of in vitro differentiation of ES cells by outlining the environmental elements required for endothelial fate specification. For each system, the efficiency of endothelial differentiation, the accessibility and the advantages are discussed. The main conclusion that arises from this analysis is that the knowledge of the role played by microenvironment in cell fate determination is essential to control and take advantage of ES cells potential. PMID: 20053368 [PubMed - as supplied by publisher] |
| Liver tissue engineering: promises and prospects of new technology.
January 8, 2010 at 6:11 am
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| | Liver tissue engineering: promises and prospects of new technology. Cytotherapy. 2010 Jan 7; Authors: Zheng MH, Ye C, Braddock M, Chen YP Abstract Today, many patients suffer from acute liver failure and hepatoma. This is an area of high unmet clinical need as these conditions are associated with very high mortality. There is an urgent need to develop techniques that will enable liver tissue engineering or generate a bioartificial liver, which will maintain or improve liver function or offer the possibility of liver replacement. Liver tissue engineering is an innovative way of constructing an implantable liver and has the potential to alleviate the shortage of organ donors for orthotopic liver transplantation. In this review we describe, from an engineering perspective, progress in the field of liver tissue engineering, including three main aspects involving cell sources, scaffolds and vascularization. PMID: 20053145 [PubMed - as supplied by publisher] |
| Osteogenic Differentiation Capacity of Porcine Dental Follicle Progenitor Cells.
January 8, 2010 at 6:11 am
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| | Osteogenic Differentiation Capacity of Porcine Dental Follicle Progenitor Cells. Connect Tissue Res. 2010 Jan 6; Authors: Tsuchiya S, Ohshima S, Yamakoshi Y, Simmer JP, Honda MJ This study examined the effect of extracellular matrix (ECM) on the osteogenic differentiation capacity and osteogenesis of dental follicle cells. Single cell-derived porcine dental follicle cells (DFC-I) obtained at the early stage of crown formation in tooth were subcultured and characterized using periodontal ligament cells (PDLC) and bone marrow-derived mesenchymal stem cells (BMSC) as comparison cell populations. The effect of ECM constituents including collagen type I, fibronectin, laminin, and collagen type IV on the differentiation of DFC-1 into osteogenic-lineage cells was evaluated in vitro. In addition, the DFC-1, PDLC, and BMSC populations were compared for osteogenic capacity in vitro by Alizarin red staining and in vivo by transplantation. DFC-I showed different features from PDLC and BMSC. Different components of ECM had different effects on the differentiation of DFC-1 into osteogenic-lineage cells in vitro. Alkaline phosphatase activity and matrix mineralization as early- and late-stage markers of osteogenesis, respectively, supported the differentiation of DFC-1 into osteogenic-related cells in vitro. All three cell types showed equivalent osteogenic capacity in vivo at 4 weeks postoperatively. There were no statistically significant differences among the cell populations with respect to capacity for bone formation. These results suggest a potential application for dental follicle cells in bone-tissue engineering. PMID: 20053131 [PubMed - as supplied by publisher] |
| Human embryonic stem-cell derivatives for full reconstruction of the pluristratified epidermis: a preclinical study.
January 8, 2010 at 6:11 am
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| | Human embryonic stem-cell derivatives for full reconstruction of the pluristratified epidermis: a preclinical study. Lancet. 2009 Nov 21;374(9703):1745-53 Authors: Guenou H, Nissan X, Larcher F, Feteira J, Lemaitre G, Saidani M, Del Rio M, Barrault CC, Bernard FX, Peschanski M, Baldeschi C, Waksman G BACKGROUND: Cell therapy for large burns is dependent upon autologous epidermis reconstructed in vitro. However, the effectiveness of current procedures is limited by the delay needed to culture the patient's own keratinocytes. To assess whether the keratinocyte progeny of human embryonic stem cells (hESCs) could be used to form a temporary skin substitute for use in patients awaiting autologous grafts, we investigated the cells' capability of constructing a pluristratified epidermis. METHODS: hESCs from lines H9 and SA01 were seeded at least in triplicate on fibroblast feeder cells for 40 days in a medium supplemented with bone morphogenetic protein 4 and ascorbic acid. Molecular characterisation of cell differentiation was done throughout the process by quantitative PCR, fluorescence-activated cell sorting, and immunocytochemical techniques. Keratinocyte molecular differentiation and functional capacity to construct a human epidermis were assessed in vitro and in vivo. FINDINGS: From hESCs, we generated a homogeneous population of cells that showed phenotypic characteristics of basal keratinocytes. Expression levels of genes encoding keratin 14, keratin 5, integrin alpha6, integrin beta4, collagen VII, and laminin 5 in these cells were similar to those in basal keratinocytes. After seeding on an artificial matrix, keratinocytes derived from hESCs (K-hESCs) formed a pluristratified epidermis. Keratin-14 immunostaining was seen in the basal compartment, with keratin 10 present in layers overlying the basal layer. Involucrin and filaggrin, late markers of epidermal differentiation, were detected in the uppermost layers only. 12 weeks after grafting onto five immunodeficient mice, epidermis derived from K-hESCs had a structure consistent with that of mature human skin. Human involucrin was appropriately located in spinous and granular layers and few Ki67-positive cells were detected in the basal layer. INTERPRETATION: hESCs can be differentiated into basal keratinocytes that are fully functional--ie, able to construct a pluristratified epidermis. This resource could be developed to provide temporary skin substitutes for patients awaiting autologous grafts. FUNDING: Institut National de la Santé et de la Recherche Médicale, University Evry Val d'Essonne, Association Française contre les Myopathies, Fondation René Touraine, and Genopole. PMID: 19932355 [PubMed - indexed for MEDLINE] |
| Bioengineered human skin from embryonic stem cells.
January 8, 2010 at 6:11 am
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| | Bioengineered human skin from embryonic stem cells. Lancet. 2009 Nov 21;374(9703):1725-6 Authors: Schlüter H, Kaur P PMID: 19932344 [PubMed - indexed for MEDLINE] |
| [Induction of hair follicle regeneration in mice ear by microencapsulated human hair dermal papilla cells]
January 8, 2010 at 6:11 am
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| | [Induction of hair follicle regeneration in mice ear by microencapsulated human hair dermal papilla cells] Zhonghua Zheng Xing Wai Ke Za Zhi. 2006 Mar;22(2):88-91 Authors: Li Y, Lin CM, Cai XN, Li GQ, Huang K OBJECTIVE: To induce the hair follicle regeneration in mice ear by microencapsulated dermal papillae cells (DPs) and to investigate the permeability of fluorescein in APA microencapsulation to search the ideal diameter of microencapsulation. METHODS: The DPs were encapsulated with alginate-polylysine-alginate by a high-voltage electric field droplet generator. The microencapsulated dermal papilla cells were xenotransplanted into the mice ears. After 6 week, the histological examination was made by microscopy. The diffusion way and speed of fluorescein into the microencapsulations were observed by confocal laser scanning microscopy. The comparison of fluorescein intensity was made in APA microencapsulations with different diameters. RESULTS: Fully developed hair follicles could be easily identified in the skin of implanted site following xenotransplantation of microencapsulation DPs, which were different from the control groups in configuration, number, size and differentiation degree. The fluorescein was diffused gradually into the microencapsulations with a shape of concentric circularity. The fluorescein intensity inside three groups of APA microencapsulations was: small > middle > big. CONCLUSIONS: The microencapsulated DPs retain the physiological function to induce the follicle regeneration. The APA microencapsulations with 400um diameter could ensure the nutrition and metabolite to pass in and out freely, and isolate the immunocompetent substance absolutely. PMID: 16736606 [PubMed - indexed for MEDLINE] |
| [Effect of adeno-BMP7 transfection on osteogenesis of BMSCs]
January 8, 2010 at 6:11 am
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| | [Effect of adeno-BMP7 transfection on osteogenesis of BMSCs] Zhonghua Zheng Xing Wai Ke Za Zhi. 2006 Jan;22(1):59-62 Authors: Zhu L, Chen FG, Liu W, Cui L, Zhou GD, Liu DL, Cao YL OBJECTIVE: To study the effect of adeno-BMP7 transfection on the biology of bone marrow stromal cells (BMSCs). METHODS: Bone marrow was obtained from the goat. The BMSCs were isolated and cultured at the second passage. Once the cells attached and formed a monolayer with 70%-80% confluency, adeno-BMP7 (M.O.I. = 100) was added to the cells. After three days, calcium node was examined with staining; cell-coral compound was replanted subcutaneously. RESULTS: With adeno-BMP7 transfection, BMP7 expression was detected with Western-blot; big calcium nodes were observed with staining. New bone formation was enhanced, which was evaluated by X-ray and histological examinations. CONCLUSIONS: BMSCs transfected with adeno-BMP7 show much stronger osteogenic ability. PMID: 16573170 [PubMed - indexed for MEDLINE] |
| [Following the fate of murine epidermal stem cells in a syngeneic dermal equivalent in vivo]
January 8, 2010 at 6:11 am
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| | [Following the fate of murine epidermal stem cells in a syngeneic dermal equivalent in vivo] Zhonghua Zheng Xing Wai Ke Za Zhi. 2005 Nov;21(6):452-6 Authors: Lin Y, Li HB, Huang JT OBJECTIVE: To follow the fate of murine epidermal stem cells (ESCs) seeded in a syngeneic dermal equivalent implanted in vivo. METHODS: Embryonic stem (ES) cells were induced in vitro to differentiate into ESCs. After stained with a fluorescent dye Hoechst 33342, these ESCs were seeded into a fibroblast-collagen-gelatin sponge complex, functioning as a dermal equivalent model, and implanted subcutaneously into 129/J mice, which were syngeneic to these stem cells. The fate of these cells was observed with HE staining, immunocytochemical staining or Van Gieson's staining. RESULTS: These ESCs were clearly visible in the implant by fluorescent microscopy 3 weeks or longer after implantation. These cells remained viable, differentiated into hair follicle-like structure, glandular structure, and gave rise to additional structures displaying features resembling native dermis. A number of markers were expressed in the differentiated structures, including CD29 (integrin beta1 subunit) and cytokeratin 18 (CK18). No apparent rejection or severe side effects were observed at least during the 10 weeks following implantation. CONCLUSION: Now that ESCs could survive in vivo in this dermal equivalent model, and differentiate into hair follicle-like structures as well as glandular structures, it is feasible to use these cells as seed cells in the study to fabricate dermal equivalent having the potential to develop dermal appendages. PMID: 16463786 [PubMed - indexed for MEDLINE] |
| [Construction and clinical application of tissue engineered epidermal membrane]
January 8, 2010 at 6:11 am
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| | [Construction and clinical application of tissue engineered epidermal membrane] Zhonghua Zheng Xing Wai Ke Za Zhi. 2005 Jul;21(4):281-4 Authors: Yang J, Yang GH, Liu W, Cui L, Qian YL, Cao YL OBJECTIVE: To Construct tissue engineered epidermal membrane for promoting healing of clinical skin graft donor site wound. METHODS: Epidermal cells /Chitosan-Gelatin (CG) membrane was constructed with cultured human epidermal cells(EC) and CG membrane, at the donor site of split skin graft, the wound was divided into three groups: the control group was covered with CG membrane without KC, KC/CG membrane was grafted on the treatment part of the wound area, and blank group was covered with traditional vaseline gauze. The engineered epidermal membrane and its effect on wound were evaluated with gross observation, HE, immunohistochemistry, collagen type I/III ratio by picrosirius polarization method and RT - PCR test at various time points before and after operation. RESULTS: The result showed that human tissue engineered epidermis could be constructed with cultured human EC and CG membrane, and this artificial epidermal membrane could be used for promoting the healing of skin graft donor site wound successfully (16 cases with 3 months' oberservation). The average healing time is (16.2 +/- 3.8) days for control group, (8.1 +/- 1.3) days for experimental group and (23.0 +/- 5.7) days for blank group. The artificial epidermis was well survived with normal structure. In addition, less hypertrophic scar development was observed in treated wound at 90 days (3 in 16 cases, 20.0%) than in the blank sites (11 in 16 cases, 74.4%). The difference is statistically significant (chi2 = 8.127, P < 0.01). CONCLUSIONS: The constructed EC-CG membrane can be constructed in vitro, survived in vivo and has good clinical application in promoting healing of skin graft donor site wound and inhibiting hypertrophic scar formation. PMID: 16248525 [PubMed - indexed for MEDLINE] |
| [Rabbit urethral defect repair with freeze-dried acellular bladder submucosa]
January 8, 2010 at 6:11 am
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| | [Rabbit urethral defect repair with freeze-dried acellular bladder submucosa] Zhonghua Zheng Xing Wai Ke Za Zhi. 2005 Jan;21(1):62-5 Authors: Wang YQ, Li YQ, Liu LQ, Xu JJ, Huo R, Li Q, Li SK OBJECTIVE: To evaluate the result of urethral defect repair using freeze-dried acellular bladder submucosa. METHODS: The freeze-dried acellular bladder submucosa was obtained from human cadaveric bladder submucosa using freeze-thawed enzymatic treatment and the freeze-drying technique. 18 male New Zealand rabbits were used in this experiment. A defect of 1.0 cm x 0.5 cm was created in the ventral urethra of the animal. The acellular matrix was grafted to the urethral defect in 14 rabbits. The other 4 animals underwent a sham operation as the controls. From postoperative one to twenty-four weeks, the animals underwent retrograde urethrography at certain intervals. The grafts of the acellular matrix were taken and prepared for histological evaluation. RESULTS: No obvious urethral stricture was observed in the 14 matrix-grafted animals. Histological examinations of the specimens showed progressive infiltration of cells and vascular vessels. Complete epithelization was obtained at 2 weeks. The orientation of collagen fibers in the matrix-grafted area tended to be regular with time. CONCLUSIONS: Freeze-dried acellular bladder submucosa may be a suitable material for urethral defect repair, which induces urethral mucous cells to migrate, grow and epithelialize. PMID: 15844603 [PubMed - indexed for MEDLINE] |
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