| 1. |
- Ahmed, Tamer A. E., et al.
(författare)
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Fibrin Glues in Combination with Mesenchymal Stem Cells to Develop a Tissue-Engineered Cartilage Substitute
- 2011
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Ingår i: Tissue Engineering. Parts A, B and C. - : Mary Ann Liebert Inc. - 2152-4947 .- 2152-4955. ; 17:3-4, s. 323-335
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Tidskriftsartikel (refereegranskat)abstract
- Damage of cartilage due to traumatic or pathological conditions results in disability and severe pain. Regenerative medicine, using tissue engineering-based constructs to enhance cartilage repair by mobilizing chondrogenic cells, is a promising approach for restoration of structure and function. Fresh fibrin (FG) and platelet-rich fibrin (PR-FG) glues produced by the CryoSeal (R) FS System, in combination with human bone marrow-derived mesenchymal stem cells (BM-hMSCs), were evaluated in this study. We additionally tested the incorporation of heparin-based delivery system (HBDS) into these scaffolds to immobilize endogenous growth factors as well as exogenous transforming growth factor-beta(2). Strongly, CD90+ and CD105+ hMSCs were encapsulated into FG and PR-FG with and without HBDS. Encapsulation of hMSCs in PR-FG led to increased expression of collagen II gene at 2.5 weeks; however, no difference was observed between FG and PR-FG at 5 weeks. The incorporation of HBDS prevented the enhancement of collagen II gene expression. BM-hMSCs in FG initially displayed enhanced aggrecan gene expression and increased accumulation of Alcian blue-positive extracellular matrix; incorporation of HBDS into these glues did not improve aggrecan gene expression and extracellular matrix accumulation. The most significant effect on cartilage marker gene expression and accumulation was observed after encapsulation of hMSCs in FG. We conclude that FG is more promising than PR-FG as a scaffold for chondrogenic differentiation of hMSCs; however, immobilization of growth factors inside these fibrin scaffolds with the HBDS system has a negative impact on this process. In addition, BM-hMSCs are valid and potentially superior alternatives to chondrocytes for tissue engineering of articular cartilage.
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| 2. |
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| 3. |
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| 4. |
- Ananta, M, et al.
(författare)
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A Poly(Lactic Acid-Co-Caprolactone)–Collagen Hybrid for Tissue Engineering Applications
- 2009
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Ingår i: Tissue engineering Part A. - : Mary Ann Liebert, Inc.. - 1937-3341 .- 1937-335X. ; 15:7, s. 1667-1675
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Tidskriftsartikel (refereegranskat)abstract
- A biodegradable hybrid scaffold consisting of a synthetic polymer, poly(lactic acid-co-caprolactone) (PLACL), and a naturally derived polymer, collagen, was constructed by plastic compressing hyperhydrated collagen gels onto a flat warp-knitted PLACL mesh. The collagen compaction process was characterized, and it was found that the duration, rather than the applied load under the test conditions in the plastic compression, was the determining factor of the collagen and cell density in the cell-carrying component. Cells were spatially distributed in three different setups and statically cultured for a period of 7 days. Short-term biocompatibility of the hybrid construct was quantitatively assessed with AlamarBlue and qualitatively with fluorescence staining and confocal microscopy. No significant cell death was observed after the plastic compression of the interstitial equivalents, confirming previous reports of good cell viability retention. The interstitial, epithelial, and composite tissue equivalents showed no macroscopic signs of contraction and good cell proliferation with a two- to threefold increase in cell number over 7 days. Quantitative analysis showed a homogenous cell distribution and good biocompatibility. The results indicate that viable and proliferating multilayered tissue equivalents can be engineered using the PLACL-collagen hybrid construct in the space of several hours.
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| 5. |
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| 6. |
- Banerjee, Debashish, et al.
(författare)
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Characterization of Decellularized Implants for Extracellular Matrix Integrity and Immune Response Elicitation
- 2022
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Ingår i: Tissue Engineering Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 28:13-14, s. 621-639
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Tidskriftsartikel (refereegranskat)abstract
- Biological scaffold is a popular choice for the preparation of tissue-engineered organs and has the potential to address donor shortages in clinics. However, biological scaffolds prepared by physical or chemical agents cause damage to the extracellular matrix (ECM) by potentially inducing immune responses after implantation. The current study explores the fate of the decellularized (DC) scaffolds using a cocktail of chemicals following implantation without using immunosuppressants. Using the syngeneic (Lewis male-Lewis female) and allogeneic (Brown Norway male-Lewis female) models and different tissue routes (subcutaneous vs. omentum) for implantation, we applied in-depth quantitative proteomics, genomics along with histology and quantitative image analysis tools to comprehensively describe and compare the proteins following DC and postimplantation. Our data helped to identify any alteration postdecullarization as well implantation. We could also monitor route-specific modulation of the ECM and regulation of the immune responses (macrophage and T cells) following implantation. The current approach opens up the possibility to monitor the fate of biological scaffolds in terms of the ECM and immune response against the implants. In addition, the identification of different routes helped us to identify differential immune responses against the implants. This study opens up the potential to identify the changes associated with chemical DC both pre- and postimplantation, which could further help to promote research in this direction. Impact StatementThe development of a biological scaffold helps in the preparation of a functional organ in the clinics. In the current study, we develop a strategy for chemical decellularization and explored two different routes to understand the differential responses elicited postimplantation. The use of sensitive protein and genomic tools to study the changes creates a favorable environment for similar efforts to develop and characterize biological scaffolds before further trials in the clinics. The current study, which was carried out without any immunosuppressive agents, could help to establish (a) appropriate chemical strategies for preparing biological scaffolds as well as (b) identify putative implantable routes to circumvent any adverse immune reactions, which will ultimately decide the outcome for acceptance or rejection of the scaffold/implant.
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| 7. |
- Bartaula-Brevik, Sushma, et al.
(författare)
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Angiogenic and Immunomodulatory Properties of Endothelial and Mesenchymal Stem Cells
- 2016
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 22:3-4, s. 244-252
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Tidskriftsartikel (refereegranskat)abstract
- It has been suggested that the effect of implanted cells on the local environment is important when selecting the appropriate cell type for tissue regeneration. Our aim was to compare the local tissue response to implanted human mesenchymal stem cells (MSC) and human umbilical vein endothelial cells (EC). MSC and EC were cultured in poly(l-lactide-co-1,5-dioxepan-2-one) scaffolds for 1 week in a bioreactor system, after which they were implanted subcutaneously in NOD/SCID mice. After 3 weeks, scaffolds were retrieved, and the mRNA expression of selected genes involved in hypoxia and inflammation was examined by real-time reverse transcription polymerase chain reaction and correlated with immunofluorescent staining for corresponding proteins. The Toll-like receptor signaling pathway was examined by superarray hybridization. The expression of 53 angiogenesis-related proteins was investigated by a proteome profiler angiogenesis antibody array kit. Vascularization was quantified using immunohistochemistry for CD31. The expression of hypoxia-inducible factors and biomarkers for angiogenesis was more strongly upregulated in response to implanted EC than to MSC, suggesting a higher sensitivity to low oxygen tension among EC. Hypoxic signaling was increased after implantation of EC compared with MSC, leading to a prolonged acute inflammatory phase that promoted ingrowth of vascular cells and establishment of the circulation. Inflammatory cytokines were also differently expressed at the gene and protein levels in the two experimental groups, resulting in altered recruitment of acute and chronic inflammatory cells. The end result of these differences was increased vessel formation within the constructs in the EC group.
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| 8. |
- Berg, Malin, 1976, et al.
(författare)
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Replacement of a Tracheal Stenosis with a Tissue-Engineered Human Trachea Using Autologous Stem Cells: A Case Report
- 2014
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Ingår i: Tissue Engineering. Part A. - 1937-3341 .- 1937-335X. ; 20:1-2, s. 389-397
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Tidskriftsartikel (refereegranskat)abstract
- Cell-based therapies, involving tissue engineering represent interesting and potentially important strategies for treatment of patients with various disorders. Here, using a detergent-enzymatic method we prepared an intact 3-dimensional scaffold of an extracellular matrix (ECM) derived from a human cadaver donor trachea, which we repopulated with autologous stem cells and implanted into a 76-year old patient with tracheal stenosis including lower part of the larynx. Although the graft provided the patient with an open airway, a week after surgery, the mucous membrane of the graft was covered by a 1-2mm thick fungal infection, which was treated with local and systemic anti-fungal therapy. The airway lumen was postoperatively controlled by fiberbrandoscopy and found stable and sufficient. However, twenty-three days later the patient died due to cardiac arrest but with a patent, open, stable tracheal transplant and intact anastomoses. Histopathological results of the transplanted tracheal graft at autopsy showed a squamous but not ciliated epithelium, neovascularization, bundles of -sma positive muscle cells, serous glands and nerve fibres with S-100 positive nerve cells in the submucosa and intact chondrocytes in the cartilage. Our findings suggest that although autologous stem cells- engineered tracheal matrices may represent a tool for clinical tracheal replacement. Further preclinical studies are required for generating functional airway grafts and long term effects of such grafts.
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| 9. |
- Bigdeli, Narmin, 1974, et al.
(författare)
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Superior Osteogenic Capacity of Human Embryonic Stem Cells Adapted to Matrix-Free Growth Compared to Human Mesenchymal Stem Cells.
- 2010
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 16:11, s. 3427-3440
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Tidskriftsartikel (refereegranskat)abstract
- Human mesenchymal stem cells (hMSCs) represent a promising source of cells for bone tissue engineering. However, their low frequencies and limited proliferation restrict their clinical utility. An alternative is the use of human embryonic stem cells (hESCs), but labor-intensive expansion with the need for coating support limits their clinical use. We have previously derived a cell line from hESCs denoted matrix-free growth (MFG)-hESC that are independent of coating support for expansion, and we here compare its osteogenic capacity to that of hMSCs. Microarray analysis of hMSCs and MFG-hESCs revealed differential expression of genes involved in ossification. MFG-hESCs have significantly higher expression of secreted phosphoprotein 1 (SPP1) during osteogenic differentiation, whereas the opposite was true for alkaline phosphatase (ALPL), transforming growth factor, beta 1 (TGFB2), runt-related transcription factor 2 (RUNX2), and forkhead box C1 (FOXC1), as well as the activity of the ALPL enzyme, demonstrating that these two cell types differentiate into the osteogenic lineage using different signaling pathways. von Kossa staining, time-of-flight secondary ion mass spectrometry, and measurement of calcium and phosphate in the extracellular matrix demonstrated a superior ability of the MFG-hESCs to produce a mineralized matrix compared to hMSCs. The superior ability of the MFG-hESCs to form mineralized matrix compared to hMSCs demonstrates that MFG-hESCs are a promising alternative to the use of adult stem cells in future bone regenerative applications.
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| 10. |
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| 11. |
- Cabric, Sanja, et al.
(författare)
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Anchoring of vascular endothelial growth factor to surface-immobilized heparin on pancreatic islets : implications for stimulating islet angiogenesis
- 2010
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 16:3, s. 961-970
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Tidskriftsartikel (refereegranskat)abstract
- In pancreatic islet transplantation, early revascularization is necessary for long-term graft function. We have shown in in vitro and in vivo models that modification with surface-attached heparin protects the islets from acute attack by the innate immune system of the blood following intraportal islet transplantation. In this study, we have investigated the ability of an immobilized conjugate composed of heparin to bind the angiogenic growth factor vascular endothelial growth factor-A (VEGF-A) as a means of attracting endothelial cells (ECs) to induce angiogenesis and revascularization. We analyzed the capacity of VEGF-A to bind to immobilized heparin and how this affected the proliferation and adherence of ECs to both artificial glass surfaces and islets. Quartz crystal microbalance with dissipation monitoring and slot-blot demonstrated the binding of VEGF-A to heparin-coated surfaces upon which ECs showed protein-dependent proliferation. Also, ECs cultured on heparin-coated glass surfaces exhibited effects upon focal contacts. Heparinized islets combined with VEGF-A demonstrated unaffected insulin release. Further, covering islets with heparin also increased the adhesion of ECs to the islet surface. Immobilized heparin on the islet surface may be a useful anchor molecule for achieving complete coverage of islets with angiogenic growth factors, ultimately improving islet revascularization and engraftment in pancreatic islet transplantation.
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| 12. |
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| 13. |
- Dare, Emma V., et al.
(författare)
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Fibrin Sealants from Fresh or Fresh/Frozen Plasma as Scaffolds for In Vitro Articular Cartilage Regeneration
- 2009
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Ingår i: TISSUE ENGINEERING PART A. - : Mary Ann Leibert Inc. - 1937-3341 .- 1937-335X. ; 15:8, s. 2285-2297
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Tidskriftsartikel (refereegranskat)abstract
- Our objective was to evaluate human CryoSeal (R) fibrin glue derived from single units of plasma as scaffolds for articular cartilage tissue engineering. Human articular chondrocytes were encapsulated into genipin cross-linked fibrin glue derived from individual units of fresh or frozen plasma using the CryoSeal (R) fibrin sealant (FS) system. The constructs were cultured for up to 7 weeks in vitro under low (5%) or normal (21%) oxygen. Chondrocyte viability was greater than90% within the fibrin gels. Hypoxia induced significant increases in collagen II and Sox9 gene expression and a significant decrease in collagen I. A significant increase in collagen II was detected in fresh plasma-derived cultures, while only collagen I was significantly increased in frozen plasma cultures. Significant increases in total glycosaminoglycan and collagen were detected in the extracellular matrix secreted by the encapsulated chondrocytes. A significant increase in compression modulus was only observed for fresh plasma-derived gels, which is likely explained by a greater amount of collagen type I detected after 7 weeks in frozen compared to fresh plasma gels. Our results indicate that CryoSeal (R) fibrin glue derived from fresh plasma is suitable as a tissue engineering scaffold for human articular chondrocytes, and therefore should be evaluated for autologous articular cartilage regeneration.
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| 14. |
- de Peppo, G.M., et al.
(författare)
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Human Embryonic Mesodermal Progenitors Highly Resemble Human Mesenchymal Stem Cells and Display High Potential for Tissue Engineering Applications
- 2010
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 16:7, s. 2161-2182
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Tidskriftsartikel (refereegranskat)abstract
- Adult stem cells, such as human mesenchymal stem cells (hMSCs), show limited proliferative capacity and, after long-term culture, lose their differentiation capacity and are therefore not an optimal cell source for tissue engineering. Human embryonic stem cells (hESCs) constitute an important new resource in this field, but one major drawback is the risk of tumor formation in the recipients. One alternative is to use progenitor cells derived from hESCs which are more lineage restricted but do not form teratomas. We have recently derived a cell line from hESCs denoted human embryonic stem cell-derived mesodermal progenitors (hESMPs) and here, using genome wide microarray analysis, report that the process of hES-MPs derivation results in a significantly altered expression of hESCs characteristic genes to an expression level highly similar to that of hMSCs. However, hES-MPs displayed a significantly higher proliferative capacity and longer telomeres. Interestingly, the hES-MPs also demonstrated a lower expression of HLA class II proteins before and after interferon-γ treatment, indicating that these cells may somewhat be immunoprivileged and potentially used for HLA-incompatible transplantation. The hES-MPs are thus an appealing alternative to hMSCs in tissue engineering applications and stem cell-based therapies for mesodermal tissues.
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| 15. |
- de Peppo, Giuseppe Maria, 1981, et al.
(författare)
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Human embryonic mesodermal progenitors highly resemble human mesenchymal stem cells and display high potential for tissue engineering applications.
- 2010
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 16:7, s. 2161-82
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Tidskriftsartikel (refereegranskat)abstract
- Adult stem cells, such as human mesenchymal stem cells (hMSCs), show limited proliferative capacity and, after long-term culture, lose their differentiation capacity and are therefore not an optimal cell source for tissue engineering. Human embryonic stem cells (hESCs) constitute an important new resource in this field, but one major drawback is the risk of tumor formation in the recipients. One alternative is to use progenitor cells derived from hESCs that are more lineage restricted but do not form teratomas. We have recently derived a cell line from hESCs denoted hESC-derived mesodermal progenitors (hES-MPs), and here, using genome-wide microarray analysis, we report that the process of hES-MPs derivation results in a significantly altered expression of hESC characteristic genes to an expression level highly similar to that of hMSCs. However, hES-MPs displayed a significantly higher proliferative capacity and longer telomeres. The hES-MPs also displayed lower expression of HLA class II proteins before and after interferon-gamma treatment, indicating that these cells may somewhat be immunoprivileged and potentially used for HLA-incompatible transplantation. The hES-MPs are thus an appealing alternative to hMSCs in tissue engineering applications and stem-cell-based therapies for mesodermal tissues.
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| 16. |
- de Peppo, Giuseppe Maria, et al.
(författare)
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Human embryonic stem cell-derived mesodermal progenitors display substantially increased tissue formation compared to human mesenchymal stem cells under dynamic culture conditions in a packed Bed/Column bioreactor
- 2013
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 19:1-2, s. 175-187
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Tidskriftsartikel (refereegranskat)abstract
- Bone tissue engineering represents a promising strategy to obviate bone deficiencies, allowing the ex vivo construction of bone substitutes with unprecedented potential in the clinical practice. Considering that in the human body cells are constantly stimulated by chemical and mechanical stimuli, the use of bioreactor is emerging as an essential factor for providing the proper environment for the reproducible and large-scale production of the engineered substitutes. Human mesenchymal stem cells (hMSCs) are experimentally relevant cells but, regardless the encouraging results reported after culture under dynamic conditions in bioreactors, show important limitations for tissue engineering applications, especially considering their limited proliferative potential, loss of functionality following protracted expansion, and decline in cellular fitness associated with aging. On the other hand, we previously demonstrated that human embryonic stem cell-derived mesodermal progenitors (hES-MPs) hold great potential to provide a homogenous and unlimited source of cells for bone engineering applications. Based on prior scientific evidence using different types of stem cells, in the present study we hypothesized that dynamic culture of hES-MPs in a packed bed/column bioreactor had the potential to affect proliferation, expression of genes involved in osteogenic differentiation, and matrix mineralization, therefore resulting in increased bone-like tissue formation. The reported findings suggest that hES-MPs constitute a suitable alternative cell source to hMSCs and hold great potential for the construction of bone substitutes for tissue engineering applications in clinical settings.
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| 17. |
- de Peppo, Giuseppe Maria, 1981, et al.
(författare)
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Osteogenic Potential of Human Mesenchymal Stem Cells and Human Embryonic Stem Cell-Derived Mesodermal Progenitors: A Tissue Engineering Perspective.
- 2010
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 16:11, s. 3413-3426
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Human mesenchymal stem cells (hMSCs) are promising candidates for bone engineering and regeneration with a considerable number of experimental successes reported over the last years. However, hMSCs show several limitations for tissue engineering applications, which can be overcome by using human embryonic stem cell-derived mesodermal progenitors (hES-MPs). The aim of this study was to investigate and compare the osteogenic differentiation potential of hMSCs and hES-MPs. Materials and Methods: The osteogenic differentiation and mineralization behavior of both cell types were evaluated at passage 5, 10, 15, and 20. Expression of COL1A1, RUNX2, OPN, and OC was evaluated by reverse transcription (RT)-polymerase chain reaction, whereas mineralization was examined by photospectrometry, von Kossa staining, and time-of-flight secondary ion mass spectrometry. The immunoprofile of both cell types was investigated by flow cytometry. Results: We demonstrated that, under proper stimulation, hES-MPs undergo osteogenic differentiation and exhibit significantly increased mineralization ability compared to hMSCs after protracted expansion. hES-MPs were also found to express lower amount of human leukocyte antigens class II proteins. Conclusions: The high osteogenic ability of hES-MPs, together with low expression of human leukocyte antigens class II, makes these cells an attractive alternative for bulk production of cells for bone engineering applications.
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| 18. |
- Deng, C, et al.
(författare)
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A Collagen-Chitosan Hydrogel for Endothelial Differentiation and Angiogenesis
- 2010
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Ingår i: TISSUE ENGINEERING PART A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 16:10, s. 3099-3109
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Tidskriftsartikel (refereegranskat)abstract
- Cell therapy for the treatment of cardiovascular disease has been hindered by low cell engraftment, poor survival, and inadequate phenotype and function. In this study, we added chitosan to a previously developed injectable collagen matrix, with the aim of improving its properties for cell therapy and neovascularization. Different ratios of collagen and chitosan were mixed and chemically crosslinked to produce hydrogels. Swell and degradation assays showed that chitosan improved the stability of the collagen hydrogel. In culture, endothelial cells formed significantly more vascular-like structures on collagen-chitosan than collagen-only matrix. While the differentiation of circulating progenitor cells to CD31(+) cells was equal on all matrices, vascular endothelial-cadherin expression was increased on the collagen-chitosan matrix, suggesting greater maturation of the endothelial cells. In addition, the collagen-chitosan matrix supported a significantly greater number of CD133(+) progenitor cells than the collagen-only matrix. In vivo, subcutaneously implanted collagen-chitosan matrices stimulated greater vascular growth and recruited more von Willebrand factor (vWF(+)) and CXCR4(+) endothelial/angiogenic cells than the collagen-only matrix. These results indicate that the addition of chitosan can improve the physical properties of collagen matrices, and enhance their ability to support endothelial cells and angiogenesis for use in cardiovascular tissue engineering applications.
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| 19. |
- di Summa, Pietro G, et al.
(författare)
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Extracellular matrix molecules enhance the neurotrophic effect of Schwann cell-like differentiated adipose-derived stem cells and increase cell survival under stress conditions
- 2013
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 19:3-4, s. 368-379
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Tidskriftsartikel (refereegranskat)abstract
- Since the first reports of induction of adipose-derived stem cells (ASC) into neuronal and glial cell phenotypes, expectations have increased regarding their use in tissue engineering applications for nerve repair. Cell adhesion to extracellular matrix (ECM) is a basic feature of survival, differentiation, and migration of Schwann cells (SC) during nerve regeneration, and fibronectin and laminin are two key molecules of this process. Interaction between ECM and SC-like differentiated ASC (dASC) could potentially improve the neurotrophic potential of the stem cells. We have investigated the effect of ECM molecules on SC-like dASC in terms of proliferation, adhesion, and cell viability. Fibronectin and laminin did not affect the proliferation of dASC when compared with cell adherent tissue culture plastic, but significantly improved viability and cell attachment when dASC were exposed to apoptotic conditions. To assess the influence of the ECM molecules on dASC neurotrophic activity, dASC were seeded onto ECM-coated culture inserts suspended above dorsal root ganglia (DRG) sensory neurons. Neurite outgrowth of DRG neurons was enhanced when dASC were seeded on fibronectin and laminin when compared with controls. When DRG neurons and dASC were in direct contact on the various surfaces there was significantly enhanced neurite outgrowth and coculture with laminin-conditioned dASC produced the longest neurites. Compared with primary SCs, dASC grown on laminin produced similar levels of neurite outgrowth in the culture insert experiments but neurite length was shorter in the direct contact groups. Anti beta 1 integrin blocking antibody could inhibit baseline and dASC evoked neurite elongation but had no effect on outgrowth mediated by laminin-conditioned dASC. ECM molecules had no effect on the levels of nerve growth factor and brain-derived neurotrophic factor secretion from dASC. The results of the study suggest that ECM molecules can significantly improve the potential of dASC for nerve regeneration.
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| 20. |
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| 21. |
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| 22. |
- Gatenholm, Paul, 1956, et al.
(författare)
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3D Bioprinting of Human Skin
- 2015
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Ingår i: Tissue Engineering Part A. - 1937-3341 .- 1937-335X. ; 21:Supplement 1
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 23. |
- Gupta, Ankur, et al.
(författare)
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Evaluation of Three-Dimensional Chitosan-Agarose-Gelatin Cryogel Scaffold for the Repair of Subchondral Cartilage Defects: An In Vivo Study in a Rabbit Model
- 2014
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 20:23-24, s. 3101-3111
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the potential of a chitosan-agarose-gelatin (CAG) cryogel scaffold for the repair of subchondral cartilage defects was explored in female New Zealand white rabbits. Custom-made CAG cryogel scaffold was implanted in a surgically created subchondral defect (diameter of 4 mm, depth of 4 mm) in knee joint of rabbit. The repair of the subchondral defect was evaluated at regular time interval by both macroscopic as well as microscopic examinations. The gross evaluation of the scaffold-implanted site showed integration of the scaffold with the surrounding tissue. Scanning electron microscopy and histological staining of the remnants of implanted cryogel scaffold showed infiltration of the host cells. The repair of the subchondral defect along with well-integrated regenerated cartilage was confirmed by the histology analysis of the joint. Results showed significant cartilage regeneration by the fourth week until eighth week after implantation. Immunohistochemical analysis confirmed that regenerated tissue is hyaline cartilage and absence of hypertrophy marker was reported. In addition, the CAG scaffolds did not elicit any adverse immunological rejection as shown by hematological analysis. Enzyme-linked immunosorbent assay did not show any statistically significant change in the concentration of tumor necrosis factor-alpha in the serum, and remained in a nontoxic range. Rabbits with a surgically created defect but no scaffold did not show any cartilage regeneration throughout the experiment of 8 weeks. These results demonstrate that CAG cryogel scaffolds promote repair of an osteochondral defect at a load-bearing site in rabbits.
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| 24. |
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| 25. |
- Gurzawska-Comis, Katarzyna, et al.
(författare)
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GUIDED BONE REGENERATION IN OSTEOPOROSIS BY PLANT-DERIVED NANOPARTICLES
- 2023
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Ingår i: Tissue Engineering. Part A. - : MARY ANN LIEBERT, INC. - 1937-3341 .- 1937-335X. ; 29:11-12, s. 576-577
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background: The repair and treatment of large bone defects in patients with compromised bone metabolism due to ageing and medical conditions such as osteoporosis present often a clinical challenge. Therefore, adjunctive methods to enhance bone healing are needed.Bone tissue engineering with application of nanotechnology allows to construct biomaterials with desired properties being osteoconductive, osteoinductive and osteogenic.Aim / Hypothesis: The aim of our study was to promote bone regeneration using functionalised scaffold with Rhamnogalacturonan-I pectins (RG-I) in vitro and in vivo using aging and osteoporotic rodent models.Material and Methods: The biomaterials were poly(l-lactide-co-ε-caprolactone) scaffolds and the RG-I was from potato. The chemical and physical properties of functionalised biomaterials with RG-I nanoparticles were characterised using confocal and atomic force microscopy. Functionalised scaffolds with RG-I (tested sample) were evaluated in vitro with human osteoblasts from osteoporotic patients and their response was tested using real-time PCR. In vivo evaluation was performed using critical-size calvaria bone defect model in ageing and osteoporotic rat models. Scaffolds were implanted randomly in the calvaria defects of aged female Wistar rats (11-12 months old) and osteoporotic female Wistar rats induced by ovariectomy. The control was scaffold without RG-I. After 2 and 8 weeks, animals were euthanised. Harvested samples were analysed for osteogenic and inflammatory markers using real-time PCR. Bone formation was evaluated radiographically and histologically. The data was analysed using one-way ANOVA.Results: The chemical and physical properties results indicated success of the functionalisation of scaffolds with RG-I. Osteoblasts response suggested osteogenic (upregulation osteopontin, osteocalcin, collagen1, bone sialoprotein) and anti-inflammatory properties (downregulation IL-1, IL-8, TNF-alpha) on the scaffold functionalised with RG-I. The in vivo results in aged and osteoporotic rat calvaria model of early (2 weeks) bone regeneration showed increase of osteogenic markers and decrease of proinflammatory markers and RANKL, compared to control. In osteoporotic rat model at week 2 and 8 and in aged rat model at week 8, the mean percentage of BV / TV (bone volume / tissue volume) in the defect with RG-I scaffold was significantly greater than the defect with control. The histological evaluation in both rat models revealed larger areas of new bone formation in RG-I scaffolds than in control.Conclusion and Clinical implications: In conclusion, the plant-derived nanoparticles significantly increased osteogenic and decreased pro-inflammatory response in vitro and in vivo. These finding may have a crucial impact on bone repair process especially in elderly and osteoporotic patients.
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| 26. |
- Hernández Vera, Rodrigo, et al.
(författare)
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Interstitial fluid flow intensity modulates endothelial sprouting in restricted Src-activated cell clusters during capillary morphogenesis
- 2009
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 15:1, s. 175-185
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Tidskriftsartikel (refereegranskat)abstract
- Development of tissues in vitro with dimensions larger than 150 to 200 microm requires the presence of a functional vascular network. Therefore, we have studied capillary morphogenesis under controlled biological and biophysical conditions with the aim of promoting vascular structures in tissue constructs. We and others have previously demonstrated that physiological values of interstitial fluid flow normal to an endothelial monolayer in combination with vascular endothelial growth factor play a critical role during capillary morphogenesis by promoting cell sprouting. In the present work, we studied the effect that a range of interstitial flow velocities (0-50 microm/min) has in promoting the amount, length, and branching of developing sprouts during capillary morphogenesis. The number of capillary-like structures developed from human umbilical vein endothelial cell monolayers across the interstitial flow values tested was not significantly affected. Instead, the length and branching degree of the sprouts presented a significant maximum at flow velocities of 10 to 20 microm/min. More-over, at these same flow values, the phosphorylation level of Src also showed its peak. We discovered that capillary morphogenesis is restricted to patches of Src-activated cells (phosphorylated Src (pSrc)) at the monolayer, suggesting that the transduction pathway in charge of sensing the mechanical stimulus induced by flow is promoting predetermined mechanically sensitive areas (pSrc) to undergo capillary morphogenesis.
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| 27. |
- Hilborn, Jöns, et al.
(författare)
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Preparing Bone Using an Injectable Hydrogel Scaffold
- 2008
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Ingår i: TERMIS EU 2008 Porto Meeting June 22–26, 2008 Porto Congress Center–Alfândega Portugal. - : Mary Ann Liebert Inc.. ; , s. 769-770
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 28. |
- Hildner, Florian, et al.
(författare)
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Human adipose-derived stem cells contribute to chondrogenesis in coculture with human articular chondrocytes.
- 2009
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 15:12, s. 3961-9
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Tidskriftsartikel (refereegranskat)abstract
- Adipose tissue is easily available and contains high numbers of stem cells that are capable for chondrogenic differentiation. We hypothesize that a partial substitution of chondrocytes with autologous adipose-derived stem cells (ASC) might be a possible strategy to reduce the number of chondrocytes needed in matrix-associated autologous chondrocyte transplantation. To lay the ground, in vitro coculture experiments were performed using human chondrocytes and human ASC. Chondrocytes were obtained from donors undergoing matrix-associated autologous chondrocyte transplantation. ASC were isolated from liposuction material. Chondrocytes and ASC were seeded either in fibrin (Tisseel; Baxter, Vienna, Austria) or collagen matrix (Tissue Fleece; Baxter, Unterschleissheim, Germany). RNA for quantitative reverse transcriptase (RT)-polymerase chain reaction was isolated after 2 weeks of culture in chondrogenic medium, and after 4 weeks samples were processed for histology. Related to the number of chondrocytes used, coculture with ASC led to strong increase in collagen type IX mRNA expression, which is an indicator for long-term stability of cartilage. Moderate upregulation was shown for SOX9, aggrecan, melanoma inhibitory activity, cartilage link protein 1, and cartilage oligomeric matrix protein mRNA. However, expression of collagen I and collagen II indicates the synthesis of fibrous tissue, which might be due to the use of dedifferentiated chondrocytes. Tisseel provided slightly better chondrogenic conditions than Tissue Fleece. These data support the possibility to take advantage of ASC in cartilage regeneration in conjunction with autologous chondrocytes.
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| 29. |
- Hingert, Daphne, et al.
(författare)
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BMP-3 Promotes Matrix Production in Co-cultured Stem Cells and Disc Cells from Low Back Pain Patients
- 2020
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Ingår i: Tissue Engineering Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 26:1-2, s. 47-56
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Tidskriftsartikel (refereegranskat)abstract
- Low back pain is one of the most common disorders and believed to be due to intervertebral disc degeneration. Transplantation of human mesenchymal stem cells (hMSCs) is suggested as potential treatment option. Bone morphogenetic growth factor 3 (BMP-3) promotes chondrogenesis and is proven effective in enhancing chondrogenesis in hMSCs pretreated with interleukin-1 beta (IL-1β) in hydrogel model. Three-dimensional co-cultures of hMSCs and disc cells (DCs) have previously been demonstrated to result in increased proteoglycan production. The aim was to study the effects of BMP-3 on hMSCs, DCs, as well as hMSCs and DCs in co-culture in a pellet system, both as single treatment and after pretreatment of IL-1β. Cell pellet cultures with hMSCs, DCs, and co-culture (1:1 ratio) were performed and stimulated with BMP-3 at 1 or 10ng/mL concentrations. For pretreatment (PRE-T), cell pellets were first stimulated with IL-1β, for 24h, and then BMP-3. The pellets were harvested on day 7, 14, and 28. Results demonstrated that BMP-3 stimulation at 10ng/mL promoted cell viability, proteoglycan accumulation, as well as chondrogenesis in all pellet groups compared to 1ng/mL. Cellular proliferation and chondrogenic differentiation of hMSCs were best promoted by PRE-T at 10ng/mL, whereas BMP-3 best enhanced chondrogenesis in DC and co-culture pellets at the same concentration.
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| 30. |
- Horstmann, Peter Frederik, et al.
(författare)
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Composite biomaterial as a carrier for bone-Active substances for metaphyseal tibial bone defect reconstruction in rats
- 2017
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Ingår i: Tissue Engineering - Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 23:23-24, s. 1403-1412
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Tidskriftsartikel (refereegranskat)abstract
- Restoring lost bone is a major challenge in orthopedic surgery. Currently available treatment strategies have shortcomings, such as risk of infection, nonunion, and excessive resorption. Our primary aim was to study if a commercially available gentamicin-containing composite calcium sulfate/hydroxyapatite biomaterial (GBM) could serve as a carrier for local delivery of bone morphogenic protein-2 (BMP-2) and zoledronic acid (ZA) in a tibia defect model in rats. Empty and allograft-filled defects were used as controls. A 3 × 4-mm metaphyseal bone defect was created in the proximal tibia, and the rats were grouped according to defect filling: (1) Empty, (2) Allograft, (3) GBM, (4) GBM + ZA, and (5) GBM + ZA + BMP-2. In vivo microcomputed tomography (micro-CT) images at 4 weeks showed significantly higher mineralized tissue volume (MV) in the intramedullary defect region and the neocortical/callus region in all GBM-Treated groups. After euthanization at 8 weeks, ex vivo micro-CT showed that addition of ZA (GBM + ZA) and BMP-2 (GBM + ZA + BMP-2) mainly increased the neocortical and callus formation, with the highest MV in the combined ZA and BMP-2-Treated group. Qualitative histological analysis, verifying the increased neocortical/callus thickness and finding of trabecular bone in all GBM-Treated groups, supported that the differences in MV measured with micro-CT in fact represented bone tissue. In conclusion, GBM can serve as a carrier for ZA and BMP-2 leading to increased MV in the neocortex and callus of a metaphyseal bone defect in rats.
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| 31. |
- Hosseini, Vahid, et al.
(författare)
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Engineered Contractile Skeletal Muscle Tissue on a Microgrooved Methacrylated Gelatin Substrate
- 2012
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Ingår i: Tissue Engineering - Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 18:23-24, s. 2453-2465
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Tidskriftsartikel (refereegranskat)abstract
- To engineer tissue-like structures, cells must organize themselves into three-dimensional (3D) networks that mimic the native tissue microarchitecture. Microfabricated hydrogel substrates provide a potentially useful platform for directing cells into biomimetic tissue architecture in vitro. Here, we present microgrooved methacrylated gelatin hydrogels as a suitable platform to build muscle-like fibrous structures in a facile and highly reproducible fashion. Microgrooved hydrogel substrates with two different ridge sizes (50 and 100 [mu m) were fabricated to assess the effect of the distance between engineered myofibers on the orientation of the bridging C2C12 myoblasts and the formation of the resulting multinucleated myotubes. It was shown that although the ridge size did not significantly affect the C2C12 myoblast alignment, the wider-ridged micropatterned hydrogels generated more myotubes that were not aligned to the groove direction as compared to those on the smaller-ridge micropatterns. We also demonstrated that electrical stimulation improved the myoblast alignment and increased the diameter of the resulting myotubes. By using the microstructured methacrylated gelatin substrates, we built free-standing 3D muscle sheets, which contracted when electrically stimulated. Given their robust contractility and biomimetic microarchitecture, engineered tissues may find use in tissue engineering, biological studies, high-throughput drug screening, and biorobotics.
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| 32. |
- Idris, Shaza B., et al.
(författare)
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Global Gene Expression Profile of Osteoblast-Like Cells Grown on Polyester Copolymer Scaffolds
- 2011
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Ingår i: Tissue Engineering. Part A. - NEW ROCHELLE, NY : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 17:21-22, s. 2817-2831
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Tidskriftsartikel (refereegranskat)abstract
- One of the principal goals in tissue engineering is to produce scaffold materials that will guide cells to differentiate and regenerate functional replacement tissue at the site of injury. Poly(l-lactide-co-1,5-dioxepan-2-one) [Poly(LLA-co-DXO)], a potential scaffolding material for bone tissue engineering, has high hydrophilicity. Previous in vitro studies using human osteoblast-like cells (HOBs) demonstrated greater cytocompatibility and enhanced osteogenic differentiation when HOBs were seeded onto Poly(LLA-co-DXO) compared to Poly(llactide) [P(LLA)] scaffolds. The aim of the study was to identify the gene expression profiles of HOBs obtained from alveolar bone and grown on Poly(LLA-co-DXO) biodegradable polymer scaffolds compared to P(LLA) one. Illumina HumanWG-6 v3.0 Expression BeadChips were used for the gene expression analysis. Several genes were found as differentially expressed at 24 h and at 21 days. Expression of genes related to cell adhesion, cytoskeleton, antiapoptosis, proliferation, and bone mineralization was influenced by adding the monomer 1,5-dioxepan-2-one to the l-lactide. Genes related to three biological pathways involving Integrin, Notch, and Ras were found to be upregulated. For selected genes, results were confirmed by quantitative reverse transcriptase– polymerase chain reaction. Further, calcium content analysis revealed a significant enhancement of calcium deposition on both tested scaffolds. This observation was confirmed by Von Kossa and Alizarin Red S staining. Findings of this study are relevant to a better understanding of the molecular mechanisms underlying the behavior of HOBs in bone regenerative procedure.
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| 33. |
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| 34. |
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| 35. |
- Kirkpatrick, Charles James
(författare)
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Developing Cellular Systems In Vitro to Simulate Regeneration
- 2014
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Ingår i: Tissue Engineering Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 20:9-10, s. 1355-1357
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Tidskriftsartikel (refereegranskat)abstract
- In the past two decades, cellular systems in vitro have progressed from predominantly monocellular testing models to study the toxic effects of new biomaterials for replacement to relevant human coculture systems for regeneration, often a combination of progenitor cells with novel biomaterials. Considerable progress has been made in understanding cellular cross talk and its contribution to the vascularization of bone. Future challenges include using the established physiological, that is, nonactivated, stem cell niches as a platform to develop coculture models, which will enable the true in situ regenerative niche to be investigated. Hypoxia and a changing inflammatory status are factors that need to be incorporated. Major advances in polymer synthesis permitting the incorporation of specific biologically relevant signals in hydrogels will help make this a reality.
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| 36. |
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| 37. |
- Koulikovska, Marina, et al.
(författare)
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Enhanced Regeneration of Corneal Tissue Via a Bioengineered Collagen Construct Implanted by a Nondisruptive Surgical Technique
- 2015
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 21:5-6, s. 1116-1130
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Tidskriftsartikel (refereegranskat)abstract
- Severe shortage of donor corneas for transplantation, particularly in developing countries, has prompted the advancement of bioengineered tissue alternatives. Bioengineered corneas that can withstand transplantation while maintaining transparency and compatibility with host cells, and that are additionally amenable to standardized low-cost mass production are sought. In this study, a bioengineered porcine construct (BPC) was developed to function as a biodegradable scaffold to promote corneal stromal regeneration by host cells. Using high-purity medical-grade type I collagen, high 18% collagen content and optimized EDC-NHS cross-linker ratio, BPCs were fabricated into hydrogel corneal implants with over 90% transparency and four-fold increase in strength and stiffness compared with previous versions. Remarkably, optical transparency was achieved despite the absence of collagen fibril organization at the nanoscale. In vitro testing indicated that BPC supported confluent human epithelial and stromal-derived mesenchymal stem cell populations. With a novel femtosecond laser-assisted corneal surgical model in rabbits, cell-free BPCs were implanted in vivo in the corneal stroma of 10 rabbits over an 8-week period. In vivo, transparency of implanted corneas was maintained throughout the postoperative period, while healing occurred rapidly without inflammation and without the use of postoperative steroids. BPC implants had a 100% retention rate at 8 weeks, when host stromal cells began to migrate into implants. Direct histochemical evidence of stromal tissue regeneration was observed by means of migrated host cells producing new collagen from within the implants. This study indicates that a cost-effective BPC extracellular matrix equivalent can incorporate cells passively to initiate regenerative healing of the corneal stroma, and is compatible with human stem or organ-specific cells for future therapeutic applications as a stromal replacement for treating blinding disorders of the cornea.
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| 38. |
- Lin, Xue, et al.
(författare)
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Controlled release of matrix metalloproteinase 1 with or without skeletal myoblasts transplantation improves cardiac function of rat hearts with chronic myocardial infarction.
- 2009
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Ingår i: Tissue engineering. Part A. - : Mary Ann Liebert Inc. - 1937-335X .- 1937-3341. ; 15:9, s. 2699-706
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Tidskriftsartikel (refereegranskat)abstract
- Skeletal myoblast transplantation has been applied clinically for severe ischemic cardiomyopathy. Matrix metalloproteinase 1 (MMP-1) reduces fibrosis and prevents the progress of heart failure. We hypothesized that MMP-1 administration to the infarct area enhances the efficacy of skeletal myoblast transplantation. The controlled release of MMP-1 improved cardiac functions of rats with chronic myocardiac infarction with or without transplantation of skeletal myoblasts. Improvement in cardiac function and small fibrotic area inside the infarcted area were observed compared with those of myoblast transplantation. In conclusion, controlled release of MMP-1 was effective in cardioprotection in postmyocardial infarction although the combination with cell transplantation showed the similar effect.
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| 39. |
- Methe, Ketaki, et al.
(författare)
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Differential Activation of Immune Cells for Genetically Different Decellularized Cardiac Tissues
- 2020
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Ingår i: Tissue Engineering Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 26:21-22, s. 1180-1198
-
Tidskriftsartikel (refereegranskat)abstract
- The immunogenicity of the extracellular matrix (ECM) from genetically similar (syngeneic) and dissimilar (allogeneic and xenogeneic) species has puzzled the scientific community for many years. After implantation, the literature describes an absorption of ECM material since it is biodegradable. However, no clear insight really exists to substantiate how the underlying immune and biological responses result in absorption of ECM materials. In this context, it is important to characterize infiltrating cells and identify dominant cell populations in the infiltrate. We have studied the immune response in mice after implantation of decellularized (DC) cardiac scaffolds derived from pig and mouse. The polymorphism of the infiltrate into the implanted material signifies the importance of the adaptive immune response that is distinct for xenoimplants and alloimplants. Matrix resorption takes place mainly through phagocytic cells such as mast cells, dendritic cells, and macrophages. Histochemical observations show that innate CD8(+)T cells develop immune tolerance, whereas proteomic analysis predicts the different T cell progenies for alloscaffolds and xenoscaffolds. The amalgamation of graft tolerance and involvement of both B and T cell populations in the vicinity of the graft could be decisive in wound remodeling and survival of the graft. This challenging area presents potential targets for the development of immune-privileged biomaterials, immune tolerant cells, and therapeutic agents in the future. Impact statement In this study, we have characterized the allogeneic and xenogeneic immune responses for decellularized (DC) cardiac scaffolds. We postulate that although the T cells are important players for immune tolerance of DC graft, the mechanism of their differentiation inside the host is donor specific. In this study, we have reported the distinct immune responses for syngeneic DC scaffolds than allogeneic and xenogeneic scaffolds. This distinct response provides the bases for the different immune responses reported for DC homografts in the literature. This study can provide the greater insight for modification of postimplant strategies to achieve host acceptance of donor extracellular matrix scaffolds.
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| 40. |
- Nayakawde, Nikhil, et al.
(författare)
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Combined Use of Detergents and Ultrasonication for Generation of an Acellular Pig Larynx
- 2021
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Ingår i: Tissue Engineering Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 27:5-6, s. 362-371
-
Tidskriftsartikel (refereegranskat)abstract
- The larynx is a fairly complex organ comprised of different muscles, cartilages, mucosal membrane, and nerves. Larynx cancer is generally the most common type of head and neck cancer. Treatment options are limited in patients with total or partial laryngectomy. Tissue-engineered organs have shown to be a promising alternative treatment for patients with laryngectomy. In this report we present an alternative and simple procedure to construct a whole pig larynx scaffold consisting of complete acellular structures of integrated muscle and cartilage. Larynges were decellularized (DC) using perfusion-agitation with detergents coupled with ultrasonication. DC larynges were then characterized to investigate the extracellular matrix (ECM) proteins, residual DNA, angiogenic growth factors, and morphological and ultrastructural changes to ECM fibers. After 17 decellularization cycles, no cells were observed in all areas of the larynx as confirmed by hematoxylin and eosin and DAPI (4 ',6-diamidino-2-phenylindole) staining. However, DC structures of dense thyroid and cricoid cartilage showed remnants of cells. All structures of DC larynges (epiglottis [p < 0.0001], muscle [p < 0.0001], trachea [p = 0.0045], and esophagus [p = 0.0008]) showed DNA <50 ng/mg compared with native larynx. Immunohistochemistry, Masson's trichrome staining, and Luminex analyses showed preservation of important ECM proteins and angiogenic growth factors in DC larynges. Compared with other growth factors, mostly retained growth factors in DC epiglottis, thyroid muscle, and trachea include granulocyte colony-stimulating factor, Leptin, fibroblast growth factor-1, Follistatin, hepatocyte growth factor, and vascular endothelial growth factor-A. Scanning electron microscopy and transmission electron microscopy analysis confirmed the structural arrangements of ECM fibers in larynges to be well preserved after DC. Our findings suggest that larynges can be effectively DC using detergent ultrasonication. ECM proteins and angiogenic growth factors appear to be better preserved using this method when compared with the native structures of larynges. This alternative DC method could be helpful in building scaffolds from dense tissue structures such as cartilage, tendon, larynx, or trachea for futurein vitrorecellularization studies orin vivoimplantation studies in the clinic. Impact statement This study successfully created decellularized porcine larynx using novel method of perfusion-agitation with detergents and ultrasonication, which maintained three-dimensional architecture of the larynx scaffold. Our method is devoid of harmful enzymes, which may prevent cellular repopulation or induce inflammatory response uponin vivoimplantation. We studied important aspect of preservation of extracellular matrix proteins in different structures of the larynx. Hence, our decellularization method could be used as an alternative method to decellularize various dense tissues such as cartilage or tendon.
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| 41. |
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| 42. |
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| 43. |
- Sladkova, Martina, et al.
(författare)
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Comparison of Decellularized Cow and Human Bone for Engineering Bone Grafts with Human Induced Pluripotent Stem Cells
- 2019
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 25:3-4, s. 288-301
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Tidskriftsartikel (refereegranskat)abstract
- Bone engineering makes it possible to grow unlimited amounts of viable tissue products for basic and applied research, and for clinical applications. A common trend in tissue engineering is the use of decellularized tissue matrices as scaffolding materials, which display structural, mechanical, and biological attributes typical of the native tissue. Due to the limited availability and high cost of human samples, decellularized tissue matrices are typically derived from animal sources. It is unclear, however, whether interspecies differences in tissue parameters will influence the quality of tissue grafts that are engineered using human stem cells. In this study, decellularized cow and human bone scaffolds were compared for engineering bone grafts using human induced pluripotent stem cell-derived mesodermal progenitor cells. After seeding, the cell-scaffold constructs were cultured for 5 weeks in osteogenic medium under dynamic conditions in perfusion bioreactors. The architectural and chemical properties of the scaffolds were studied using microscopic, spectroscopic, and thermogravimetric techniques, while cell behavior and formation of mineralized tissue were assessed using a combination of molecular assays, histological methods, and imaging technologies. The results show that while scaffolds derived from cow and human bone differ somewhat in architecture and composition, both equally support cell viability, tissue growth, and formation of a mineralized bone matrix. Taken together, the results suggest that scaffolds derived from cow bone represent a suitable and convenient alternative to engineer human bone grafts for various biomedical applications.
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| 44. |
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| 45. |
- Tukmachev, Dmitry, et al.
(författare)
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Injectable Extracellular Matrix Hydrogels as Scaffolds for Spinal Cord Injury Repair
- 2016
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 22:3-4, s. 306-317
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Tidskriftsartikel (refereegranskat)abstract
- Restoration of lost neuronal function after spinal cord injury (SCI) still remains a big challenge for current medicine. One important repair strategy is bridging the SCI lesion with a supportive and stimulatory milieu that would enable axonal rewiring. Injectable extracellular matrix (ECM)-derived hydrogels have been recently reported to have neurotrophic potential in vitro. In this study, we evaluated the presumed neuroregenerative properties of ECM hydrogels in vivo in the acute model of SCI. ECM hydrogels were prepared by decellularization of porcine spinal cord (SC) or porcine urinary bladder (UB), and injected into a spinal cord hemisection cavity. Histological analysis and real-time qPCR were performed at 2, 4, and 8 weeks postinjection. Both types of hydrogels integrated into the lesion and stimulated neovascularization and axonal ingrowth into the lesion. On the other hand, massive infiltration of macrophages into the lesion and rapid hydrogel degradation did not prevent cyst formation, which progressively developed over 8 weeks. No significant differences were found between SC-ECM and UB-ECM. Gene expression analysis revealed significant downregulation of genes related to immune response and inflammation in both hydrogel types at 2 weeks post SCI. A combination of human mesenchymal stem cells with SC-ECM did not further promote ingrowth of axons and blood vessels into the lesion, when compared with the SC-ECM hydrogel alone. In conclusion, both ECM hydrogels bridged the lesion cavity, modulated the innate immune response, and provided the benefit of a stimulatory substrate for in vivo neural tissue regeneration. However, fast hydrogel degradation might be a limiting factor for the use of native ECM hydrogels in the treatment of acute SCI.
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| 46. |
- Vaithilingam, Vijayaganapathy, et al.
(författare)
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Beneficial Effects of Coating Alginate Microcapsules with Macromolecular Heparin Conjugates-In Vitro and In Vivo Study
- 2014
-
Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert Inc. - 1937-3341 .- 1937-335X. ; 20:1-2, s. 324-334
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Tidskriftsartikel (refereegranskat)abstract
- Pericapsular fibrotic overgrowth (PFO) is associated with poor survival of encapsulated pancreatic islets. Modification of the microcapsule membrane aimed at preventing PFO should improve graft survival. This study investigated the effect of macromolecular Corline Heparin Conjugate (CHC) binding on intrinsic properties of alginate microcapsules and assessed the anti-fibrotic potential of this strategy both in vitro and in vivo. CHC was bound to alginate microcapsules using a layer-by-layer approach incorporating avidin. CHC binding to alginate microcapsule was visualized by confocal microscopy. Effects of CHC binding on microcapsule size, strength, and permeability were assessed, and the anti-clotting activity of bound CHC was determined by coagulation assay. Effect of CHC binding on the viability of encapsulated human islets was assessed in vitro, and their ability to function was assessed both in vitro and in vivo in diabetic immunodeficient mice. The potential of bound CHC to reduce PFO was assessed in vivo in different rat transplantation models. Confocal microscopy demonstrated a uniform coating of CHC onto the surface of microcapsules. CHC binding affected neither size nor permeability but significantly increased the tensile strength of alginate microcapsules by similar to 1.3-fold. The bound CHC molecules were stable and retained their anti-clotting activity for 3 weeks in culture. CHC binding affected neither viability nor function of the encapsulated human islets in vitro. In vivo CHC binding did not compromise islet function, and diabetes was reversed in all recipients with mice exhibiting lower blood glucose levels similar to controls in oral glucose tolerance tests. CHC binding was beneficial and significantly reduced PFO in both syngeneic and allogeneic rat transplantation models by similar to 65% and similar to 43%, respectively. In conclusion, our results show a new method to successfully coat CHC on alginate microcapsules and demonstrate its beneficial effect in increasing capsule strength and reduce PFO. This strategy has the potential to improve graft survival of encapsulated human islets.
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| 47. |
- Xing, Zhe, et al.
(författare)
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Biological Effects of Functionalizing Copolymer Scaffolds with Nanodiamond Particles
- 2013
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Ingår i: Tissue Engineering. Part A. - : Mary Ann Liebert. - 1937-3341 .- 1937-335X. ; 19:15-16, s. 1783-1791
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Tidskriftsartikel (refereegranskat)abstract
- Significant evidence has indicated that poly(L-lactide)-co-(epsilon-caprolactone) [(poly(LLA-co-CL)] scaffolds could be one of the suitable candidates for bone tissue engineering. Oxygen-terminated nanodiamond particles (n-DP) were combined with poly(LLA-co-CL) and revealed to be positive for cell growth. In this study, we evaluated the influence of poly(LLA-co-CL) scaffolds modified by n-DP on attachment, proliferation, differentiation of bone marrow stromal cells (BMSCs) in vitro, and on bone formation using a sheep calvarial defect model. BMSCs were seeded on either poly(LLA-co-CL)-or n-DP-coated scaffolds and incubated for 1 h. Scanning electron microscopy (SEM) and fluorescence microscopy were used in addition to protein and DNA measurements to evaluate cellular attachment on the scaffolds. To determine the effect of n-DP on proliferation of BMSCs, cell/scaffold constructs were harvested after 3 days and evaluated by Bicinchoninic Acid (BCA) protein assay and SEM. In addition, the osteogenic differentiation of cells grown for 2 weeks on the various scaffolds and in a dynamic culture condition was evaluated by real-time RT-PCR. Unmodified and modified scaffolds were implanted into the calvaria of six-year-old sheep. The expression of collagen type I (COL I) and bone morphogenetic protein-2 (BMP-2) after 4 weeks as well as the formation of new bone after 12 and 24 weeks were analyzed by immunohistochemistry and histology. Scaffolds modified with n-DP supported increased cell attachment and the mRNA expression of osteopontin (OPN), bone sialoprotein (BSP), and BMP-2 were significantly increased after 2 weeks of culture. The BMSCs had spread well on the various scaffolds investigated after 3 days in the study with no significant difference in cell proliferation. Furthermore, the in vivo data revealed more positive staining of COLI and BMP-2 in relation to the n-DP-coated scaffolds after 4 weeks and presented more bone formation after 12 and 24 weeks. n-DP modification significantly increased cell attachment and differentiation of BMSCs on poly(LLA-co-CL) scaffolds in vitro and enhanced bone formation in vivo.
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| 48. |
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| 49. |
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| 50. |
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