| 1. |
- Karlsson, Camilla, 1977, et al.
(författare)
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Differentiation of human mesenchymal stem cells and articular chondrocytes: analysis of chondrogenic potential and expression pattern of differentiation-related transcription factors.
- 2007
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Ingår i: Journal of orthopaedic research : official publication of the Orthopaedic Research Society. - : Wiley. - 0736-0266. ; 25:2, s. 152-63
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Tidskriftsartikel (refereegranskat)abstract
- Mesenchymal stem cells (MSCs) are a candidate for replacing chondrocytes in cell-based repair of cartilage lesions. However, it has not been clarified if these cells can acquire the hyaline phenotype, and whether chondrocytes and MSCs show the same expression patterns of critical control genes in development. In order to study this, articular chondrocytes and iliac crest derived MSCs were allowed to differentiate in pellet mass cultures. Gene expression of markers for the cartilage phenotype, helix-loop-helix (HLH) transcription factors, and chondrogenic transcription factors were analyzed by real-time PCR. Matrix production was assayed using biochemical analysis for hydroxyproline, glycosaminoglycans, and immunohistochemistry for collagen types I and II. Significantly decreased expression of collagen type I was accompanied by increased expression of collagen types IIA and IIB during differentiation of chondrocytes, indicating differentiation towards a hyaline phenotype. Chondrogenesis in MSCs on the other hand resulted in up-regulation of collagen types I, IIA, IIB, and X, demonstrating differentiation towards cartilage of a mixed phenotype. Expression of HES1 increased significantly during chondrogenesis in chondrocytes while expression in MSCs was maintained at a low level. The HLH gene HES5 on the other hand was only detected in chondrocytes. Expression of ID1 decreased significantly in chondrocytes while the opposite was seen in MSCs. These findings suggest that chondrocytes and MSCs differentiated and formed different subtypes of cartilage, the hyaline and a mixed cartilage phenotype, respectively. Differentially regulated HLH genes indicated the possibility for HLH proteins in regulating chondrogenic differentiation. This information is important to understand the potential use of MSCs in cartilage repair.
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| 2. |
- Brisby, Helena, 1965, et al.
(författare)
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The presence of local mesenchymal progenitor cells in human degenerated intervertebral discs and possibilities to influence these in vitro: A descriptive study in humans
- 2013
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Ingår i: Stem Cells and Development. - : Mary Ann Liebert Inc. - 1547-3287 .- 1557-8534. ; 22:5, s. 804-814
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Tidskriftsartikel (refereegranskat)abstract
- Low back pain is common and degenerated discs are believed to be a major cause. In non-degenerated intervertebral discs(IVDs) presence of stem-/progenitor cells was recently reported in different mammals (rabbit,rat,pig). Understanding processes of disc degeneration and regenerative mechanisms within degenerated discs(DDs) is important. The aim of the study was to examine presence of local stem-/progenitor cells in human DDs and if these cell-populations could respond to paracrin stimulation in vitro. Tissue biopsies from the IVD region (L3-S1) was collected from 15 patients, age 34-69 years, undergoing surgery (spinal fusion) and mesenchymal stem cells (MSCs)(iliac crest) from two donors. Non-degenerated disc cells were collected from one donor(scoliosis) and chordoma tissue was obtained from(positive control, stem cell markers) two donors. The IVD biopsies were investigated for gene- and protein expression of: OCT3/4, CD105, CD90, STRO-1 and NOTCH1. DD cell cultures(pellet mass) were performed with conditioned media from MSCs and non-degenerated IVD cells. Pellets were investigated after 7, 14, 28 days for the same stem cell markers as above. Gene expression of OCT3/4 and STRO-1 was detected in 13/15 patient samples, CD105 in 14/15 samples and CD90 and NOTCH1 was detected 15/15 samples. Immunohistochemistry analysis supported findings on protein level, in cells sparsely distributed in DDs tissues. DDs cell-cultures displayed more undifferentiated appearance with increased expression of CD105, CD90, STRO-1, OCT3/4, NOTCH1 and JAGGED1 which was observed when cultured in conditioned cell-culture media from MSC compared to cell-cultures cultured with conditioned media from non-degenerated disc cells. Expression of OCT3/4(multipotency marker) and NOTCH1(regulator of cell fate), MSC- markers CD105, CD90 and STRO-1 indicate that primitive cell populations are present within DDs. Furthermore, the possibility to influence cells from DDs by by paracrin signalling /soluble factors from MSCs and from non-degenerated IVD cells was observed in vitro indicating that repair processes within human degenerated discs may be stimulated.
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| 3. |
- Åberg, Jonas, 1982-, et al.
(författare)
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Biocompatibility and resorption of a radiopaque premixed calcium phosphate cement
- 2012
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Ingår i: Journal of Biomedical Materials Research. Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 100A:5, s. 1269-1278
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Tidskriftsartikel (refereegranskat)abstract
- Calcium phosphate cements (CPC) are used as bone void filler in various orthopedic indications; however, there are some major drawbacks regarding mixing, transfer, and injection of traditional CPC. By using glycerol as mixing liquid, a premixed calcium phosphate cement (pCPC), some of these difficulties can be overcome. In the treatment of vertebral fractures the handling characteristics need to be excellent including a high radio-opacity for optimal control during injection. The aim of this study is to evaluate a radiopaque pCPC regarding its resorption behavior and biocompatibility in vivo. pCPC and a water-based CPC were injected into a circle divide 4-mm drilled femur defect in rabbits. The rabbits were sacrificed after 2 and 12 weeks. Cross sections of the defects were evaluated using histology, electron microscopy, and immunohistochemical analysis. Signs of inflammation were evaluated both locally and systemically. The results showed a higher bone formation in the pCPC compared to the water-based CPC after 2 weeks by expression of RUNX-2. After 12 weeks most of the cement had been resorbed in both groups. Both materials were considered to have a high biocompatibility since no marked immunological response was induced and extensive bone ingrowth was observed. The conclusion from the study was that pCPC with ZrO2 radiopacifier is a promising alternative regarding bone replacement material and may be suggested for treatment of, for example, vertebral fractures based on its high biocompatibility, fast bone ingrowth, and good handling properties.
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