| 1. |
- Barreto Henriksson, Helena, et al.
(författare)
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Identification of Cell Proliferation Zones, Progenitor Cells and a Potential Stem Cell Niche in the Intervertebral Disc Region: A Study in Four Species.
- 2009
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Ingår i: SPINE. - 0362-2436. ; 34:21, s. 2278-2287
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Tidskriftsartikel (refereegranskat)abstract
- STUDY DESIGN.: Descriptive experimental study in 4 different mammals. OBJECTIVE.: To investigate cell proliferation/regeneration and localize stem cells/progenitor cells within the intervertebral disc (IVD). SUMMARY OF BACKGROUND DATA.: Disc degeneration (DD) is believed to play a major role in patients with chronic lumbar pain. Lately, biologic treatment options for DD have gained increasing interest. Normal regeneration processes within the IVD and have previously been sparsely described and therefore it is of great interest to increase the knowledge about these processes. METHODS.: Detection of cell proliferations zones and label-retaining cells were done by in vivo 5-bromo-2-deoxyuridine (BrdU) labeling in 18 rabbits, killed after 4, 6, 10, 14, 28, or 56 days. Results were visualized with immunohistochemistry and fluorescence/confocal microscopy. Localization of progenitor cell were further investigated by immunohistochemistry using antibodies towards Notch1, Delta4, Jagged1, C-KIT, KI67, and Stro-1 in normal IVD from rabbits (n = 3), rats (n = 2), minipigs (n = 2), and in human degenerated IVD (n = 4). Further, flowcytometry analysis using progenitor markers were performed on additional human IVD cells (n = 3). RESULTS.: BrdU positive cells were found in comparable numbers at early and late time points in most regions of the anulus fibrosus (AF) and nucleus pulposus demonstrating slow ongoing cell proliferation. In the AF border to ligament zone (AFo) and the perichondriumregion (P) a stem cell niche-like pattern was determined (a high number of BrdU positive cells at early time points vs. only a few label retaining cells at later time points). In normal and DD tissue from the 4 investigated species progenitor cell markers were detected. CONCLUSION.: The IVD is a tissue with ongoing slow cell proliferation both in the AF and the nucleus pulposus. The stem cell niche pattern detected in AFo and P can be suggested to play a role for IVD morphology and function. These findings may be of importance for the development of biologic treatment strategies. PMID: 19755937 [PubMed - as supplied by publisher]
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| 2. |
- Björntorp, Elisabeth, et al.
(författare)
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The helix-loop-helix transcription factor Id1 is highly expressed in psoriatic involved skin.
- 2003
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Ingår i: Acta dermato-venereologica. - : Medical Journals Sweden AB. - 0001-5555. ; 83:6, s. 403-9
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Tidskriftsartikel (refereegranskat)abstract
- The helix-loop-helix transcription factor Id1 (inhibitor of differentiation/inhibitor of DNA binding) functions as an inhibitor of differentiation. We have examined Id1 gene expression in cultured keratinocytes in punch biopsies from psoriatic involved and uninvolved skin, and in skin specimens from normal individuals. Id1 mRNA expression was measured with an RNase protection assay and with Northern blot. Id1 immunoreactivity was determined in skin biopsies by immunofluorescence using a polyclonal antibody directed against the Id1 protein. In cultured keratinocytes, the expression of Id1 mRNA was strongest in small cells with high proliferative potential, whereas in large cells, which are terminally differentiated, the expression was low. Expression of the Id1 mRNA in psoriatic involved skin (n = 9) was significantly elevated compared to uninvolved skin from the same patient (n = 5) and to skin from normal controls (n = 9). Id1 immunoreactivity was intranuclear throughout all the layers in psoriatic involved epidermis, except in the stratum corneum, while no immunoreactivity was detected in uninvolved epidermis. In normal controls, cytoplasmatic Id1 immunoreactivity was detected in the basal layer in epidermis obtained from newborns, while no immunoreactivity was detected in epidermis obtained from the adults in the control group. We conclude that Id1 is expressed in cells with high proliferative potential, and is downregulated in cells that undergo terminal differentiation. Along with the overexpression of the Id1 gene in psoriatic involved skin, these observations suggest that Id1 is involved in the process of differentiation of keratinocytes seen in normal skin and that the Id1 pathway is activated in psoriasis.
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| 3. |
- Brittberg, Mats, 1953, et al.
(författare)
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Clonal growth of human articular cartilage and the functional role of the periosteum in chondrogenesis.
- 2005
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Ingår i: Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. - : Elsevier BV. - 1063-4584. ; 13:2, s. 146-53
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Clinical cartilage repair with transplantation of cultured chondrocytes, the first described technique introduced in 1994, includes a periosteal membrane but today cells are also implanted without the periosteal combination. The aim of this study was to see if the periosteum had more than a biomechanical function and if the periosteum had a biological effect on the seeded cells tested in an agarose system in which the clonal growth in agarose and the external growth stimulation could be analysed. METHODS: Four different experiments were used to study the growth of human chondrocytes in agarose and the periosteal influence. Human chondrocytes were isolated and transferred to either primary or secondary agarose culture. After 4 weeks, the total number of clones >50 microm was counted. Cocultures of chondrocytes and periosteal tissue, cultures of chondrocytes with conditioned medium from chondrocytes, periosteal cells and fibroblast were used to study a potential stimulatory effect on growth and different cytokines and growth factors were analysed. RESULTS: It was found that the human chondrocytes had different growth properties in agarose with the formation of four different types of clones: a homogenous clone without matrix production, a homogenous clone with matrix production, a differentiated clone with matrix production and finally a differentiated clone without matrix production. The periosteum exerted a paracrine effect on cultured chondrocytes in agarose resulting in a higher degree of cloning. The chondrocytes produced significant amounts of interleukin (IL)-6, IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF) and transforming growth factor (TGF)-beta. The periosteum produced significant amounts of IL-6, IL-8 and TGF-beta. Cocultures of chondrocytes and periosteum demonstrated a potentiation of IL-6 and IL-8 release but not of TGF-beta and GM-CSF. CONCLUSION: Articular chondrocytes are able to form clones of different properties in agarose and the periosteum has a capacity of stimulating chondrocyte clonal growth and differentiation and secretes significant amounts of IL-6, IL-8, GM-CSF and TGF-beta. It may be that the repair of cartilage defects with seeded chondrocytes could benefit from the combination with a periosteal graft. The production of TGF-beta by implanted chondrocytes could influence the chondrogenic cells in the periosteum to start a periosteal chondrogenesis and together with the matrix from implanted chondrocyte production, a repair of cartilaginous appearance may develop; a dual chondrogenic response is possible.
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| 4. |
- Karlsson, Camilla, 1977, et al.
(författare)
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Identification of a stem cell niche in the zone of Ranvier within the knee joint.
- 2009
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Ingår i: Journal of anatomy. - : Wiley. - 0021-8782 .- 1469-7580. ; 215:3, s. 355-363
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Tidskriftsartikel (refereegranskat)abstract
- A superficial lesion of the articular cartilage does not spontaneously self-repair and has been suggested to be partly due to lack of progenitor cells within the joint that can reach the site of injury. To study whether progenitor cells are present within the joint, 3-month-old New Zealand white rabbits were exposed to bromodeoxyuridine (BrdU) for 12 consecutive days and were then sacrificed 4, 6, 10, 14, 28 and 56 days after the first BrdU administration. Presence of BrdU and localization of progenitor markers were detected using immunohistochemistry. After 10 days of BrdU exposure, BrdU-positive cells, i.e. proliferating cells, were abundantly detected in the epiphyseal plate, the perichondrial groove of Ranvier, and in all zones of the articular cartilage. After a wash-out period, BrdU-positive cells were still present, i.e. those considered to be progenitor cells, in these regions of the knee except for the proliferative zone of the epiphyseal plate. Cells in the perichondrial groove of Ranvier were further positive for several markers associated with progenitor cells and stem cell niches, including Stro-1, Jagged1, and BMPr1a. Our results demonstrate that a small population of progenitor cells is present in the perichondrial groove of Ranvier as well as within the articular cartilage in the knee. The perichondrial groove of Ranvier also demonstrates the properties of a stem cell niche.
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| 5. |
- Sköldberg, Filip, et al.
(författare)
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Identification of AHNAK as a novel autoantigen in systemic lupus erythematosus.
- 2002
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Ingår i: Biochemical and biophysical research communications. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 291:4, s. 951-8
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Tidskriftsartikel (refereegranskat)abstract
- To identify candidate autoantigens associated with arthritis, a rat chondrocyte cDNA library was immunoscreened with serum from a patient with rheumatoid arthritis. One isolated cDNA encoded part of AHNAK, a 700-kDa phosphoprotein with DNA binding properties, that appears to be involved in several signal transduction pathways. Immunoreactivity against an in vitro translated human AHNAK fragment was detected in 4.6% (5/109) of patients with rheumatoid arthritis, 29.5% (18/61) of patients with systemic lupus erythematosus (SLE), and 1.2% (2/172) of blood donors. Anti-AHNAK antibodies reacted with a recombinant human AHNAK fragment and with native AHNAK from C32 cell lysates. In vitro translated AHNAK fragment could be cleaved by granzyme B and caspase-3. Anti-AHNAK positive SLE patients had a higher frequency of homogeneous antinuclear antibody staining patterns and a lower frequency of recent mucosal ulcerations. This is the first report that AHNAK can be targeted by the immune system in autoimmune disease.
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| 6. |
- Thornemo, Maria, 1968, et al.
(författare)
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Clonal populations of chondrocytes with progenitor properties identified within human articular cartilage.
- 2005
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Ingår i: Cells, tissues, organs. - : S. Karger AG. - 1422-6405 .- 1422-6421. ; 180:3, s. 141-50
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to identify and characterize progenitor properties of human articular chondrocytes selected by using agarose suspension culture. In this chondrogenic selective culture condition, about 3.6% of seeded surplus chondrocytes from patients undergoing articular chondrocyte transplantation proliferated and formed cell clusters after 6 weeks. Phase-contrast microscopy and transmission electron microscopy revealed four different types of cell clusters differing in cellular content and matrix production. Based on their morphological features, they were named the homogenous (H), the homogenous matrix (HM), the differentiated matrix (DM) and the differentiated (D) cell clusters. All cell clusters showed positive safranin O staining, and matrix was positive for antibodies detecting type II collagen and aggrecan. The clusters were further demonstrated to express the genes for fibroblast growth factor receptor 3, type IIA collagen and type IIB collagen, while type X collagen was not expressed. After subcloning, the H and HM clusters demonstrated the best proliferative capacity. Chondrocytes from these two cell clusters also showed phenotypic plasticity in chondrogenic, adipogenic as well as osteogenic assays. This study demonstrates that existing subpopulations of cells with chondroprogenitor properties can be isolated from human adult articular cartilage using agarose suspension cultures.
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