| Embryonic Stem Cells Proliferate and Differentiate when Seeded into Kidney Scaffolds.
September 5, 2009 at 6:16 am
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| | Embryonic Stem Cells Proliferate and Differentiate when Seeded into Kidney Scaffolds. J Am Soc Nephrol. 2009 Sep 3; Authors: Ross EA, Williams MJ, Hamazaki T, Terada N, Clapp WL, Adin C, Ellison GW, Jorgensen M, Batich CD The scarcity of transplant allografts for diseased organs has prompted efforts at tissue regeneration using seeded scaffolds, an approach hampered by the enormity of cell types and complex architectures. Our goal was to decellularize intact organs in a manner that retained the matrix signal for differentiating pluripotent cells. We decellularized intact rat kidneys in a manner that preserved the intricate architecture and seeded them with pluripotent murine embryonic stem cells antegrade through the artery or retrograde through the ureter. Primitive precursor cells populated and proliferated within the glomerular, vascular, and tubular structures. Cells lost their embryonic appearance and expressed immunohistochemical markers for differentiation. Cells not in contact with the basement membrane matrix became apoptotic, thereby forming lumens. These observations suggest that the extracellular matrix can direct regeneration of the kidney, and studies using seeded scaffolds may help define differentiation pathways. PMID: 19729441 [PubMed - as supplied by publisher] |
| FIBROBLAST GROWTH FACTOR RECEPTORS IN IN-VITRO AND IN-VIVO CHONDROGENESIS: RELATING TISSUE ENGINEERING USING ADULT MESENCHYMAL STEM CELLS TO EMBRYONIC DEVELOPMENT.
September 5, 2009 at 6:16 am
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| | FIBROBLAST GROWTH FACTOR RECEPTORS IN IN-VITRO AND IN-VIVO CHONDROGENESIS: RELATING TISSUE ENGINEERING USING ADULT MESENCHYMAL STEM CELLS TO EMBRYONIC DEVELOPMENT. Tissue Eng Part A. 2009 Sep 3; Authors: Hellingman CA, Koevoet W, Kops N, Farrell E, Jahr H, Liu W, Baatenburg de Jong RJ, Frenz D, van Osch G Adult mesenchymal stem cells (MSCs) are considered promising candidate cells for therapeutic cartilage and bone regeneration. Because tissue regeneration and embryonic development may involve similar pathways, understanding common pathways may lead to advances in regenerative medicine. In embryonic limb development Fibroblast Growth Factor Receptors (FGFR) play a role in chondrogenic differentiation. The aim of this study was to investigate and compare FGFR expression in in-vivo embryonic limb development and in-vitro chondrogenesis of MSCs. Our study showed that, in both models, in in-vitro chondrogenesis of MSCs consisted of three subsequent sequential stages can be found, as in embryonic limb development. A mesenchymal condensation (indicated by N-cadherin) is followed by chondrogenic differentiation (indicated by collagen II), and hypertrophy (indicated by collagen X). FGFR1-3 are expressed in a stage-dependent pattern during in-vitro differentiation and in-vivo embryonic limb development. In both models FGFR2 is clearly expressed by cells in the condensation phase. No FGFR expression was observed in differentiating and mature hyaline chondrocytes, while hypertrophic chondrocytes stained strongly for all FGFRs. Therefore, FGFR expression in pellet cultures of MSCs resembled embryonic endochondral ossification. To evaluate whether stage-specific modulation of chondrogenesis chondrogenic differentiation in MSCs is possible with different subtypes of FGF, FGF2 and FGF9 were added to the chondrogenic medium during different stages in the culture process (early or late). FGF2 and FGF9 differentially affected the amount of cartilage formed by MSCs depending on the stage in which it was added. These results will help us understand the role of FGF signaling in chondrogenesis and find new tools to monitor and control chondrogenic differentiation. PMID: 19728793 [PubMed - as supplied by publisher] |
| High Content Drug Screening with Engineered Musculoskeletal Tissues.
September 5, 2009 at 6:16 am
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| | High Content Drug Screening with Engineered Musculoskeletal Tissues. Tissue Eng Part B Rev. 2009 Sep 3; Authors: Vandenburgh H Tissue engineering for in vitro drug screening applications based on tissue function is an active area of translational research. Compared to targeted high throughput screening (HTS) methods that rapidly analyze hundreds of thousands of compounds affecting a single biochemical reaction or gene expression, high content screening (HCS) with engineered tissues is more complex and based on the cumulative positive and negative effects of a compound on the multiple pathways altering tissue function. It may therefore serve as better predictor of in vivo activity and serve as a bridge between HTS and in vivo animal studies. In the case of the musculoskeletal system, tissue function includes determining improvements in the mechanical properties of bone, tendon, cartilage, and, for skeletal muscle, contractile properties such as rate of contraction/relaxation, force generation, fatigability, and recovery from fatigue. HCS of compound banks with engineered tissues requires miniature musculoskeletal 'organs' as well as automated functional testing. The resulting technologies should be rapid, cost effective, and reduce the number of small animals required for follow-on in vivo studies. Identification of compounds that improve the repair/regeneration of damaged tissues in vivo would have extensive clinical applications for treating musculoskeletal disorders. PMID: 19728786 [PubMed - as supplied by publisher] |
| 3D hydrogel model using adipose-derived stem cells for vocal fold augmentation.
September 5, 2009 at 6:16 am
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| | 3D hydrogel model using adipose-derived stem cells for vocal fold augmentation. Tissue Eng Part A. 2009 Sep 3; Authors: Park H, Karajanagi S, Wolak K, Aanestad J, Deheron L, Kobler J, Lopez-Guerra G, Heaton J, Langer RS, Zeitels S Adipose-derived stem cells (ASCs) may provide a clinical option for rebuilding damaged superficial lamina propria (SLP) of the vocal fold. We investigated the effects of five hydrogels (hyaluronic acid (HA), collagen, fibrin, and co-gels of fibrin-collagen and fibrin-HA) on the differentiation of ASCs, with the long term goal of establishing the conditions necessary for controlling the differentiation of ASC into the functional equivalent of SLP fibroblasts. Human ASCs were isolated and characterized by FACS and real time PCR. According to FACS and gene analysis, over 90% of isolated ASCs expressed adult stem cell surface markers and expressed adult stem cell genes. Scaffold-specific gene expression and morphology were assessed by culturing the ASCs in 3-D hydrogels. Two-fold higher amounts of total DNA were detected in fibrin and co-gel cultures compared to collagen and HA cultures. Elastin expression was significantly higher in cells grown in fibrin-based gels compared to cells grown in other gels. Cells grown in the co-gels showed elongated morphology, expressed decorin marker and glycosaminoglycan synthesis, which indicate ASC differentiation. Our data suggest that it may be possible to control the differentiation of ASCs using scaffolds appropriate for vocal fold tissue engineering applications. In particular, co-gels of HA or collagen with fibrin enhanced proliferation, differentiation and elastin expression. PMID: 19728785 [PubMed - as supplied by publisher] |
| Considerations for Tissue Engineered and Regenerative Medicine Product Development Prior to Clinical Trials.
September 5, 2009 at 6:16 am
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| | Considerations for Tissue Engineered and Regenerative Medicine Product Development Prior to Clinical Trials. Tissue Eng Part B Rev. 2009 Sep 3; Authors: Lee MH, Arcidiacono JA, Bilek AM, Wille JJ, Hamill CA, Wonnacott KM, Wells MA, Oh SS Tissue Engineered and Regenerative Medicine (TE/RM) products are promising innovative therapies that can address unmet clinical needs. These products are often combinations of cells, scaffolds and other factors and are complex in both structure and function. The complexity introduces challenges for product developers to establish novel manufacturing and characterization techniques to ensure that these products are safe and effective prior to clinical trials in humans. While there are a few commercial products that are currently on the market, many more TE/RM products are under development. Therefore, it is the purpose of this paper to help product developers in the early stages of product development by providing insight into the Food and Drug Administration (FDA) process and by highlighting some of the key scientific considerations that may be applicable to their products. We provide resources that are publically available from the FDA and others that are of potential interest. As the provided information is general in content, product developers should contact the FDA for feedback regarding their specific products. Also described are ways through which product developers can informally and formally interact with the FDA early in the development process to help in the efficient progression of products toward clinical trials. PMID: 19728784 [PubMed - as supplied by publisher] |
| [Preparation and biocompatibility evaluation of novel cartilage acellular matrix sponge]
September 5, 2009 at 6:16 am
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| | [Preparation and biocompatibility evaluation of novel cartilage acellular matrix sponge] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2009 Aug;23(8):1002-6 Authors: Liu T, Tan B, Luo J, Deng L, Xie H OBJECTIVE: To explore the method of preparing spongy and porous scaffold materials with swine articular cartilage acellular matrix and to investigate its applicability for tissue engineered articular cartilage scaffold. METHODS: Fresh swine articular cartilage was freeze-dried and freeze-ground into microparticles. The microparticles with diameter of less than 90 microm were sieved and treated sequentially with TNE, pepsin and hypotonic solution for decellularization at cryogenic temperatures. Colloidal suspension with a mass/volume ratio of 2% was prepared by dissolving the microparticles into 1.5% HAc, and then was lyophilized for molding and cross-linked by UV radiation to prepare the decellularized cartilage matrix sponge. Physicochemical property detection was performed to identify aperture, porosity and water absorption rate. Histology and scanning electron microscope observations were conducted. The prepared acellular cartilage matrix sponge was implanted into the bilateral area of spine in 24 SD rats subcutaneously (experimental group), and the implantation of Col I sponge served as control group. The rats were killed 1, 2, 4, and 8 weeks after operation to receive histology observation, and the absorption and degeneration conditions of the sponge in vivo were analyzed. BMSCs obtained from femoral marrow of 1-week-old New Zealand white rabbits were cultured. The cells at passage 3 were cultured with acellular cartilage matrix sponge lixivium at 50% (group A), acellular cartilage matrix sponge lixivium at 100% (group B), and DMEM culture medium (group C), respectively. Cell proliferation was detected by MTT method 2, 4, and 6 days after culture. RESULTS: The prepared acellular cartilage matrix sponge was white and porous. Histology observation suggested that the sponge scaffold consisted primarily of collagen without chondrocyte fragments. Scanning electron microscope demonstrated that the scaffold had porous and honeycomb-shaped structure, the pores were interconnected and even in size. The water absorption rate was 20.29% +/- 25.30%, the aperture was (90.66 +/- 21.26) microm, and the porosity of the scaffold was 90.10% +/- 2.42%. The tissue grew into the scaffold after the subcutaneous implantation of scaffold into the SD rats, angiogenesis was observed, inflammatory reaction was mild compared with the control group, and the scaffold was degraded and absorbed at a certain rate. MTT detection suggested that there were no significant differences among three groups in terms of absorbance (A) value 2 and 4 days after culturing with the lixivium (P > 0.05), but significant differences were evident among three groups 6 days after culturing with the lixivium (P < 0.05). CONCLUSION: With modified treatment and processing, the cartilage acellular matrix sponge scaffold reserves the main components of cartilage extracellular matrix after thorough decellularization, has appropriate aperture and porosity, and provides even distribution of pores and good biocompatibility without cytotoxicity. It can be used as an ideal scaffold for cartilage tissue engineering. PMID: 19728622 [PubMed - in process] |
| [Experimental study of repairing full-thickness articular cartilage defect with chondrocyte-sodium alginate hydrogel-SIS complex]
September 5, 2009 at 6:16 am
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| | [Experimental study of repairing full-thickness articular cartilage defect with chondrocyte-sodium alginate hydrogel-SIS complex] Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 2009 Aug;23(8):974-9 Authors: Mo X, Deng L, Li X, Xie H, Luo J, Guo S, Yang Z OBJECTIVE: To explore the effect of tissue engineered cartilage reconstructed by using sodium alginate hydrogel and SIS complex as scaffold material and chondrocyte as seed cell on the repair of full-thickness articular cartilage defects. METHODS: SIS was prepared by custom-made machine and detergent-enzyme treatment. Full-thickness articular cartilage of loading surface of the humeral head and the femoral condyle obtained from 8 New Zealand white rabbits (2-3 weeks old) was used to culture chondrocytes in vitro. Rabbit chondrocytes at passage 4 cultured by conventional multiplication method were diluted by sodium alginate to (5-7) x 10(7) cells/mL, and then were coated on SIS to prepare chondrocyte-sodium alginate hydrogel-SIS complex. Forty 6-month-old clean grade New Zealand white rabbits weighing 3.0-3.5 kg were randomized into two groups according to different operative methods (n = 20 rabbits per group), and full-thickness cartilage defect model of the unilateral knee joint (right or left) was established in every rabbit. In experimental group, the complex was implanted into the defect layer by layer to construct tissue engineered cartilage, and SIS membrane was coated on the surface to fill the defect completely. While in control group, the cartilage defect was filled by sodium alginate hydrogel and was sutured after being coated with SIS membrane without seeding of chondrocyte. General condition of the rabbits after operation was observed. The rabbits in two groups were killed 1, 3, 5, 7, and 9 months after operation, and underwent gross and histology observation. RESULTS: Eight rabbits were excluded due to anesthesia death, wound infection and diarrhea death. Sixteen rabbits per group were included in the experiment, and 3, 3, 3, 3, and 4 rabbits from each group were randomly selected and killed 1, 3, 5, 7, and 9 months after operation, respectively. Gross observation and histology Masson trichrome staining: in the experimental group, SIS on the surface of the implant was fused with the host tissue, and the inferface between them disappeared 1 month after operation; part of the implant was chondrified and the interface between the implant and the host tissue was fused 3 months after operation; the implant turned into fibrocartilage 5 months after operation; fiber arrangement of the cartilage in the implant was close to that of the host tissue 7 months after operation; cartilage fiber in the implant arranged disorderly and active cell metabolism and proliferation were evident 9 months after operation. While in the control group, no repair of the defect was observed 9 months after operation. No obvious repair was evident in the defects of the control group within 9 months after operation. Histomorphometric evaluation demonstrated that the staining intensity per unit area of the reparative tissue in the defect of the experimental group was significant higher than that of the control group at each time point (P < 0.05), the chondrification in the experimental group was increased gradually within 3, 5, and 7 months after operation (P < 0.05), and it was decreased 9 months after operation comparing with the value at 7 months after operation (P < 0.05). CONCLUSION: Constructed by chondrocyte-sodium alginate hydrogel-SIS in complex with surficial suturing of SIS membrane, the tissue engineered cartilage can in-situ repair cartilage defect, promote the regeneration of cartilage tissue, and is in line with physiological repair process of articular cartilage. PMID: 19728617 [PubMed - in process] | | | 
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