| 1. |
- Backesjo, CM, et al.
(author)
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Activation of Sirt1 decreases adipocyte formation during osteoblast differentiation of mesenchymal stem cells
- 2009
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 189:1-4, s. 93-97
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Journal article (peer-reviewed)abstract
- Mesenchymal stem cells (MSC) can differentiate into osteoblasts, adipocytes, chondrocytes and myoblasts. It has been suggested that a reciprocal relationship exists between the differentiation of MSC into osteoblasts and adipocytes. Peroxisome proliferator-activated receptor γ2 (PPARγ2) is a key element for the differentiation into adipocytes. Activation of the nuclear protein deacetylase Sirt1 has recently been shown to decrease adipocyte development from preadipocytes via inhibition of PPARγ2. In vitro, MSC differentiate to osteoblasts when exposed to bone-inducing medium. However, adipocytes are also developed. In the present study we have targeted Sirt1 to control adipocyte development during differentiation of MSC into osteoblasts. The finding that resveratrol and isonicotinamide markedly inhibited adipocyte and promoted osteoblast differentiation demonstrates an interesting alternative to PPARγ antagonists. These results are important for the evolving field of cell-based tissue engineering, but may also be relevant in the search for new treatments of osteoporosis.
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| 2. |
- Dare, Emma V., et al.
(author)
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Genipin Cross-Linked Fibrin Hydrogels for in vitro Human Articular Cartilage Tissue-Engineered Regeneration
- 2009
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In: Cells Tissues Organs. - : Karger. - 1422-6405 .- 1422-6421. ; 190:6, s. 313-325
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Journal article (peer-reviewed)abstract
- Our objective was to examine the potential of a genipin cross-linked human fibrin hydrogel system as a scaffold for articular cartilage tissue engineering. Human articular chondrocytes were incorporated into modified human fibrin gels and evaluated for mechanical properties, cell viability, gene expression, extracellular matrix production and subcutaneous biodegradation. Genipin, a naturally occurring compound used in the treatment of inflammation, was used as a cross-linker. Genipin cross-linking did not significantly affect cell viability, but significantly increased the dynamic compression and shear moduli of the hydrogel. The ratio of the change in collagen II versus collagen I expression increased more than 8-fold over 5 weeks as detected with real-time RT-PCR. Accumulation of collagen II and aggrecan in hydrogel extracellular matrix was observed after 5 weeks in cell culture. Overall, our results indicate that genipin appeared to inhibit the inflammatory reaction observed 3 weeks after subcutaneous implantation of the fibrin into rats. Therefore, genipin cross-linked fibrin hydrogels can be used as cell-compatible tissue engineering scaffolds for articular cartilage regeneration, for utility in autologous treatments that eliminate the risk of tissue rejection and viral infection.
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| 3. |
- Fossum, Magdalena, et al.
(author)
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Long-term culture of human urothelial cells : a qualitative analysis
- 2005
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In: Cells Tissues Organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 181:1, s. 11-22
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Journal article (peer-reviewed)abstract
- Today, in vitro culturing of autologous cells is an established method in the field of tissue reconstruction. It can be applied to urothelial cells and could have many clinical implications in urological reconstructive surgery. This development calls for quality controls concerning cells used for clinical treatment when cells are autotransplanted back to the patient. We have studied cultured cells in order to detect whether genetic or morphologic changes occur. Urothelial cells isolated from bladder lavage were cultured according to different protocols based on the presence or absence of feeder cells. Genetic studies were performed by means of karyotyping with standard G-banding and interphase fluorescent in situ hybridization (FISH) analyses. The morphology of these epithelial cells was judged as well as immunostaining for epithelial cell markers. In addition, to minimize the risk of feeder cell contamination, proliferation studies were performed on cultures including feeder cells that had been pretreated with different doses of mitomycin or radiation. In initial studies, when using feeder cells in each passage according to standard protocols, urothelial cells proliferated unfavourably after the fourth passage with increasing numbers of mouse cells as well as urothelial tetraploid cells. We could also show that urothelial cells from bladder lavage need feeder cells in order to establish primary cultures. Further propagation up to 14 passages was performed without feeder cells and the urothelial cells retained normal karyotypes. We also found that mitomycin treatment had its main effect on feeder cells during the first 2 h. When feeder cells were irradiated, 20 Gy was effective and no feeder cell contamination was seen. In conclusion, we found that a high standard of quality in urothelial cell culturing can be achieved with a careful culturing technique.
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| 4. |
- Grimsholm, Ola, et al.
(author)
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Expression patterns of neurotrophins and neurotrophin receptors in articular chondrocytes and inflammatory infiltrates in knee joint arthritis.
- 2008
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 188:3, s. 299-309
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Journal article (peer-reviewed)abstract
- BACKGROUND: It is likely that neurotrophins (NTs) are of great importance for the articular cartilage and the inflammation process in arthritis. METHODS: The immunohistochemical expression of the NTs nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) and the associated receptors p75, TrkA and TrkB was examined in the knee joint of arthritic and healthy mice. RESULTS: Immunoreactions for NGF and BDNF were detected in cells and nerve fiber varicosities in the inflammatory infiltrates of the synovial tissue of arthritic joints but not in synovial tissue of controls. p75-immunoreactive nerve fiber-like strands were detected in inflammatory infiltrates. Immunostaining for NGF, BDNF, p75, TrkA and TrkB was noted in articular chondrocytes. There was a statistically significant decrease in reactions for NGF (p < 0.001), TrkA (p = 0.001) and p75 (p < 0.001) in articular chondrocytes in joints exhibiting severe arthritis. CONCLUSION: The findings show that an NT system develops in inflammatory infiltrates of the synovial tissue. Furthermore, most interestingly, autocrine/paracrine effects appear to exist concerning NTs for the articular chondrocytes. The downregulated expression of NGF and NT receptors in articular chondrocytes in arthritis is a new aspect concerning the involvement of NTs in cartilage.
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| 5. |
- Hellström, Martin, et al.
(author)
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Expression of the CD44 receptor in the blood vessel system : an experimental study in rat.
- 2005
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In: Cells Tissues Organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 179:3, s. 102-108
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Journal article (peer-reviewed)abstract
- The CD44 receptor is a transmembrane glycoprotein expressed on a variety of cells like endothelial, epithelial and smooth muscle cells. This molecule has many important functions, e.g. in cell-cell and cell-matrix interactions and signal transduction. The main ligand for CD44 is hyaluronan (HYA). HYA is a glycosaminoglycan with structural and cell biological properties. The localization of HYA in the vessel wall of arteries and veins in the healthy adult and newborn rat has been described earlier. In this study the occurrence of the CD44 receptor was investigated in the same vessels and compared to the localization of HYA. Both CD44 and its ligand showed an increased expression in the vessel wall of newborn rats compared to that of adult rats. Although HYA is abundant in the adventitia of adult rats, virtually no expression of CD44 was observed. Our results indicate that the CD44 receptor expression is increased during the stage of maturation of the vessel tree whereas the CD44 receptor is less needed by HYA in the healthy vessel wall.
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| 6. |
- Karlsson, Camilla, 1977, et al.
(author)
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Neither Notch1 expression nor cellular size correlate with mesenchymal stem cell properties of adult articular chondrocytes.
- 2008
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 187:4, s. 275-85
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Journal article (peer-reviewed)abstract
- BACKGROUND: Tissue repair is thought to be regulated by progenitor cells, which in other tissues are characterized by their Notch1 expression or small cellular size. Here we studied if these traits affect the chondrogenic potential and are markers for multipotent progenitor cell populations in adult articular cartilage. METHODS: Directly isolated articular chondrocytes were sorted with regard to their Notch1 expression or cellular size. Their colony forming efficiency (CFE) and their potential to differentiate towards adipogenic, osteogenic and chondrogenic lineages were investigated. The different sorted populations were also expanded in monolayer and analyzed in the same manner as the directly isolated cells. RESULTS: No differences in CFE or adipogenic, osteogenic and chondrogenic potentials were detected among the sorted populations. Expanded cells displayed a higher osteochondral potential than directly isolated cells. CONCLUSION: Cellular size or Notch1 expression is not per se a specific marker for mesenchymal progenitor cells in adult articular cartilage. Monolayer-expanded adult chondrocytes contain a larger mesenchymal progenitor cell-like population than directly isolated cells, highly likely as a result of dedifferentiation. If there are resident Notch1-positive cells or cells of a specific size in adult articular cartilage with functional features of progenitor cells, the population consists of only a very small number of cells.
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| 7. |
- Karlsson, Camilla, 1977, et al.
(author)
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Notch1, Jagged1, and HES5 are abundantly expressed in osteoarthritis.
- 2008
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 188:3, s. 287-98
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Journal article (peer-reviewed)abstract
- BACKGROUND: Notch signalling controls differentiation and proliferation in various cell types and is associated with several diseases. We investigated the localization and regulation of several Notch markers in human osteoarthritic (OA) cartilage as well as identified genes controlled by Notch signalling. METHODS: Immunolocalization and real-time PCR analysis of Notch markers in healthy and OA articular cartilage were performed. Genes regulated by Notch signalling were studied using microarray. Cytokine-induced transcription of Notch markers was analyzed using real-time PCR and its effect on cellular localization of the intracellular domain of Notch1 (NICD1) was investigated using immunohistochemistry, subcellular fractionation, and transfection. The effect of NFkappaB activation on HES5 transcription was studied using the NFkappaB inhibitor pyrrolidine dithiocarbamate. RESULTS: Notch signalling was activated in OA cartilage and Notch1, Jagged1, and HES5 were abundantly expressed compared to healthy cartilage. Notch signalling regulated the expression of several genes associated with OA, like interleukin-8, lubricin, CD10, matrix metalloproteinase-9, and bone morphogenetic protein-2. Cytokines significantly affected the expression of several Notch markers and repressed expression of HES5, but did not affect the cellular localization of NICD1. CONCLUSION: Notch signalling is dysregulated in OA, inducing and repressing transcription of genes that could potentially partly contribute to the OA phenotype.
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| 8. |
- Kopp, S, et al.
(author)
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Reduction of temporomandibular joint pain after treatment with a combination of methotrexate and infliximab is associated with changes in synovial fluid and plasma cytokines in rheumatoid arthritis
- 2005
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 180:1, s. 22-30
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Journal article (peer-reviewed)abstract
- The aims were to investigate the effect of intravenous infusions of the tumor necrosis factor-α (TNF-α) antibody infliximab on symptoms and signs of temporomandibular joint (TMJ) involvement in relation to effects on synovial fluid and plasma proinflammatory TNF-α, interleukin-1β (IL-1β) and interleukin-6 as well as antiinflam matory soluble TNF receptor II (TNF-sRII), interleukin-1 receptor antagonist (IL-1ra), soluble IL-1 receptor II (IL-1sRII) and interleukin-10 (IL-10) in patients with active rheumatoid arthritis (RA). Nineteen patients with TMJ involvement taking methotrexate were included in the study. TMJ and general joint pain intensity as well as pain on mandibular movements, tenderness to digital palpation, pressure pain threshold and maximum mouth-opening capacity were assessed in a clinical examination. The effect of infliximab was assessed after 2 and 14 or 22 weeks. TMJ synovial fluid and venous blood were collected for cytokine analysis at all occasions while determination of erythrocyte sedimentation rate and C-reactive protein were performed at baseline and at long-term follow-up only. Reduction of TMJ pain was associated with raised levels of synovial fluid TNF-sRII and IL-1sRII as well as raised plasma levels of IL-1ra and IL-10. Decreased erythrocyte sedimentation rate was associated with decreased tenderness to digital palpation. Reduced general joint pain intensity was associated with reduced plasma levels of IL-6 and C-reactive protein. In conclusion, systemic treatment with a combination of infliximab and methotrexate reduces TMJ pain in RA in association with an increase in anti-inflammatory cytokines and receptors in synovial fluid and plasma.
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| 9. |
- Melnick, M., et al.
(author)
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Meckel's cartilage differentiation is dependent on hedgehog signaling
- 2005
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In: Cells Tissues Organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 179:4, s. 146-157
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Journal article (peer-reviewed)abstract
- The hedgehog (Hh) signaling pathway has been shown to be essential for craniofacial development. Although mandibular arch derivatives are largely absent in Shh null mice, little is known about the role of Hh signaling during Meckel's cartilage development per se. Mandible development is dependent on the morphogenesis of Meckel's cartilage, which then serves as a template for subsequent skeletal differentiation. In this study, we examine the biological function of Hh signaling during Meckel's cartilage development in vivo and in vitro. E13.5 Shh null mice present a small mesenchymal condensation in the region of a presumptive Meckel's cartilage in the hypoplastic mandibular arch. By E15.5, the Shh mutant exhibits a mere remnant of the mandibular arch, without evidence of Meckel's cartilage differentiation. Further, wild-type embryonic (E11 or E12) mandibular explants cultured for up to 5 days in the presence of cyclopamine, a steroidal alkaloid that specifically disrupts the Hh signaling pathway, exhibit a stage-dependent inhibition of Meckel's cartilage chondroblast differentiation to mature chondrocytes. This phenotype can be rescued by exogenous FGF8, a downstream effector of Hh signaling. Taken together, our results indicate that the Hh signaling pathway is critical to Meckel's cartilage ontogenesis and the rate of chondrogenesis, but not to initial primordium formation. The reliance on Hh signaling is stage dependent. Copyright (C) 2005 S. Karger AG, Basel.
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| 10. |
- Tallheden, Tommi, 1972, et al.
(author)
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Human articular chondrocytes--plasticity and differentiation potential.
- 2006
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In: Cells, tissues, organs. - : S. Karger AG. - 1422-6421 .- 1422-6405. ; 184:2, s. 55-67
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Journal article (peer-reviewed)abstract
- Articular cartilage has no or very low ability of self-repair, and untreated lesions may lead to the development of osteoarthritis. One method which has been proven to result in long-term repair of isolated lesions is autologous chondrocyte transplantation. In this method, culture-expanded chondrocytes isolated from full-thickness biopsies, taken from a non-weight-bearing area at the supromedial edge of the femoral condyle, are transplanted back to the patient under a cover of periosteum. The treatment is able to regenerate hyaline cartilage with long-term durability. Although the repair mechanism behind this treatment has not been fully elucidated, emerging data generated by microarray technologies reveal an interesting regeneration process involving cellular and molecular mechanisms found during fetal development. In hyaline cartilage, the human chondrocyte population is generally considered a homogenous cell population, but recently several investigators have demonstrated that cells isolated from human articular cartilage have stem cell properties and that the superficial layer contains such cells. This paper will discuss these recent data and their implications for future treatment strategies aiming to induce regeneration in articular cartilage surfaces.
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