| 1. |
- Julkunen, Petro, et al.
(författare)
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Biomechanical, biochemical and structural correlations in immature and mature rabbit articular cartilage.
- 2009
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Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 17:12, s. 1628-1638
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The structure and composition of articular cartilage change during development and growth. These changes lead to alterations in the mechanical properties of cartilage. In the present study, biomechanical, biochemical and structural relationships of articular cartilage during growth and maturation of rabbits are investigated.DESIGN: Articular cartilage specimens from the tibial medial plateaus and femoral medial condyles of female New Zealand white rabbits were collected from seven age-groups; 0 days (n=29), 11 days (n=30), 4 weeks (n=30), 6 weeks (n=30), 3 months (n=24), 6 months (n=24) and 18 months (n=19). The samples underwent mechanical testing under creep indentation. From the mechanical response, instantaneous and equilibrium moduli were determined. Biochemical analyses of tissue collagen, hydroxylysylpyridinoline (HP) and pentosidine (PEN) cross-links in full thickness cartilage samples were conducted. Proteoglycans were investigated depth-wise from the tissue sections by measuring the optical density of Safranin-O-stained samples. Furthermore, depth-wise collagen architecture of articular cartilage was analyzed with polarized light microscopy. Finite element analyses of the samples from different age-groups were conducted to reveal tensile and compressive properties of the fibril network and the matrix of articular cartilage, respectively.RESULTS: Tissue thickness decreased from approximately 3 to approximately 0.5mm until the age of 3 months, while the instantaneous modulus increased with age prior to peak at 4-6 weeks. A lower equilibrium modulus was observed before 3-month-age, after which the equilibrium modulus continued to increase. Collagen fibril orientation angle and parallelism index were inversely related to the instantaneous modulus, tensile fibril modulus and tissue thickness. Collagen content and cross-linking were positively related to the equilibrium compressive properties of the tissue.CONCLUSIONS: During maturation, significant modulation of tissue structure, composition and mechanical properties takes place. Importantly, the present study provides insight into the mechanical, chemical and structural interactions that lead to functional properties of mature articular cartilage.
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| 2. |
- Silvast, Tuomo, et al.
(författare)
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pQCT study on diffusion and equilibrium distribution of iodinated anionic contrast agent in human articular cartilage – associations to matrix composition and integrity.
- 2009
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Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 17:1, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: X-ray imaging of articular cartilage using anionic contrast agents has been introduced for quantification of tissue glycosaminoglycan (GAG) concentration. In this in vitro study we investigated diffusion and equilibrium distribution of an anionic contrast agent in human articular cartilage and related the results to tissue composition and integrity.METHODS: Osteochondral cylinders (d=4.0mm, n=24) were prepared from femoral medial condyles (FMCs, cartilage thickness 2.13+/-0.54 mm, mean+/-standard deviation [SD]), and tibial medial plateaus ([TMPs]1.99+/-0.38 mm) of human cadaver knees. Samples were immersed for 24h at room temperature in 21 mM concentration of anionic contrast agent Hexabrix. The X-ray absorption maps and profiles were measured before immersion, and after every 2h of immersion using clinical peripheral quantitative computed tomography (pQCT).RESULTS: An increase in X-ray attenuation along cartilage depth, indicating a characteristic density profile increasing from superficial to deep tissue, could be seen in pQCT images acquired without contrast agent. The complete diffusion of the contrast agent into cartilage took more than 12h. However, the uronic acid concentration correlated with the contrast agent concentration in femoral cartilage (r=-0.76, n=12, P=0.004) as early as after 2h of immersion, and the linear correlation was virtually unchanged during the remaining 22 h. Similarly, the histological tissue integrity (Mankin score) correlated positively with the contrast agent concentration in tibial cartilage (r=+0.75, P=0.005) after 2h of immersion. The X-ray absorption profiles before immersion, i.e., without the contrast agent, and after 24h of immersion were significantly correlated (r=-0.76+/-0.34, mean+/-SD).CONCLUSIONS: Although the complete contrast agent diffusion into human articular cartilage in vitro took more than 12h, significant apparent correlations were revealed between the spatial proteoglycan (PG) and contrast agent distributions already after 2h of immersion. At the stage of incomplete penetration, however, the spatial contrast agent concentration distribution cannot directly reflect the true PG distribution as the Donnan equilibrium has not been reached. However, in degenerated cartilage the diffusion rate increases. Obviously, this can lead to the reported correlation between the bulk PG content and the bulk contrast agent concentration already at the early stages of diffusion.
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| 3. |
- Wang, Wei-Zhou, et al.
(författare)
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Comparative analysis of gene expression profiles between the normal human cartilage and the one with endemic osteoarthritis.
- 2009
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Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 17:1, s. 83-90
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the differences in gene expression profiles of adult articular cartilage with endemic osteoarthritis (OA), Kashin-Beck disease (KBD), and the same regions in the normal joint.METHODS: The messenger RNA expression profiles of articular cartilage with KBD diagnosed according to "Diagnosing Criteria of Kashin-Beck Disease in China" were compared with the normal cartilage. Total RNA isolated separately from four pairs of the KBD and normal cartilage samples were evaluated by oligonucleotide microarray analysis. The microarray data were confirmed by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) amplification and were compared with previously published experiments.RESULTS: About 4100 transcripts, which corresponded to 35% of the expressed transcripts, showed >or=twofold differences in expression between the cartilage tissues in pairs. Approximately 2% of the expressed genes (79, 55 genes expressed in KBD>normal; 24 genes expressed in KBDCONCLUSION: Differences between KBD cartilage and the normal exhibited a similar pattern among the four pairs examined, indicating the presence of common mechanisms mainly including chondrocyte metabolism and apoptosis that contribute to cartilage destruction in KBD.
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| 4. |
- Qu, Cheng-Juan, 1967-, et al.
(författare)
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Effects of glucosamine sulfate on intracellular UDP-hexosamine and UDP-glucuronic acid levels in bovine primary chondrocytes.
- 2007
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Ingår i: Osteoarthritis and Cartilage. - : Saunders Elsevier. - 1063-4584 .- 1522-9653. ; 15:7, s. 773-779
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To analyze the effects of exogenously added glucose (Glc), glucosamine (GlcN) and glucosamine sulfate (GS) on the intracellular UDP-hexoses (UDP-Hex), UDP-N-acetylhexosamines (UDP-HexN) and UDP-glucuronic acid (UDP-GlcA) levels in bovine primary chondrocytes.METHODS: Chondrocytes were incubated with different concentrations of Glc, GlcN and GS either in high- or low-glucose DMEM for up to 120min to analyze the intracellular levels of UDP-Hex, UDP-GlcA and UDP-HexN by a reversed-phase high-performance liquid chromatography-electrospray ionization mass spectrometry analysis. Glycosaminoglycan (GAG) synthesis rate and aggrecan mRNA expression levels were quantified using (35)S-sulfate incorporation assay and quantitative real-time RT-PCR, respectively. The cells were cultivated for 2 days or 8 days before UDP-sugar analysis.RESULTS: Levels of UDP-HexN and UDP-GlcA were unchanged at 10microM concentration of GS in low-glucose DMEM, while addition of 1mM GlcN or GS in low-glucose DMEM for 10min increased UDP-HexN level. The highest intracellular level of UDP-HexN was reached at 30min after addition of 1mM GS to the cells. The intracellular contents of UDP-HexN and UDP-GlcA related to UDP-Hex were higher after prolonged cultivation of chondrocytes for 8 days compared with 2-day-old cultures. Aggrecan mRNA expression and GAG synthesis remained at control level after the cells were treated with 10, 100microM or 1mM of GS for 24h.CONCLUSION: Physiologically relevant level of GS could not increase the intracellular UDP-HexN and UDP-GlcA levels in bovine primary chondrocyte, while longer-time culture itself appeared to increase the intracellular UDP-HexN and UDP-GlcA levels.
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| 5. |
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| 6. |
- Stattin, Eva-Lena, 1960-, et al.
(författare)
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Familial osteochondritis dissecans associated with early osteoarthritis and disproportionate short stature
- 2008
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Ingår i: Osteoarthritis and Cartilage. - London : Elsevier BV. - 1063-4584 .- 1522-9653. ; 16:8, s. 890-6
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Familial osteochondritis dissecans (OCD) is a rare disorder characterised by disturbed chondro-skeletal development, disproportionate growth and deformation of the skeleton. DESIGN: We identified a five-generation family with 15 living affected members from Northern Sweden. The disorder was diagnosed with a case definition of OCD in at least one joint. RESULTS: Main clinical findings consisted of OCD in knees and/or hips and/or elbows, disproportionate short stature and early osteoarthritis (OA). There were no radiological indications of epiphyseal dysplasia. Anthropometric measurements of affected individuals showed short stature, a high ratio between sitting height and total height, a relatively normal arm span and head circumference. In 12 of 15 cases, onset was during late childhood or adolescence and OA had developed in seven of those patients. CONCLUSIONS: Our observation suggests that OA is a frequent complication in familial OCD even though the lesions appear before closure of physis.
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| 7. |
- Stenhamre, Hanna, et al.
(författare)
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Topographic variation in redifferentiation capacity of chondrocytes in the adult human knee joint.
- 2008
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Ingår i: Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. - : Elsevier BV. - 1522-9653 .- 1063-4584. ; 16:11, s. 1356-62
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this study was to investigate the topographic variation in matrix production and cell density in the adult human knee joint. Additionally, we have examined the redifferentiation potential of chondrocytes expanded in vitro from the different locations. METHOD: Full thickness cartilage-bone biopsies were harvested from seven separate anatomical locations of healthy knee joints from deceased adult human donors. Chondrocytes were isolated, expanded in vitro and redifferentiated in a pellet mass culture. Biochemical analysis of total collagen, proteoglycans and cellular content as well as histology and immunohistochemistry were performed on biopsies and pellets. RESULTS: In the biochemical analysis of the biopsies, we found lower proteoglycan to collagen (GAG/HP) ratio in the non-weight bearing (NWB) areas compared to the weight bearing (WB) areas. The chondrocytes harvested from different locations in femur showed a significantly better attachment and proliferation ability as well as good post-expansion chondrogenic capacity in pellet mass culture compared with the cells harvested from tibia. CONCLUSION: These results demonstrate that there are differences in extra cellular content within the adult human knee in respect to GAG/HP ratio. Additionally, the data show that clear differences between chondrocytes harvested from femur and tibia from healthy human knee joints exist and that the differences are not completely abolished during the process of de- and redifferentiation. These findings emphasize the importance of the understanding of topographic variation in articular cartilage biology when approaching new cartilage repair strategies.
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| 8. |
- Vasara, Anna I, et al.
(författare)
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Immature porcine knee cartilage lesions show good healing with or without autologous chondrocyte transplantation.
- 2006
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Ingår i: Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society. - : Elsevier BV. - 1063-4584 .- 1522-9653. ; 14:10, s. 1066-74
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The purpose of this study was to find out how deep chondral lesions heal in growing animals spontaneously and after autologous chondrocyte transplantation. METHODS: A 6mm deep chondral lesion was created in the knee joints of 57 immature pigs and repaired with autologous chondrocyte transplantation covered with periosteum or muscle fascia, with periosteum only, or left untreated. After 3 and 12 months, the repair tissue was evaluated with International Cartilage Repair Society (ICRS) macroscopic grading, modified O'Driscoll histological scoring, and staining for collagen type II and hyaluronan, and with toluidine blue and safranin-O staining for glycosaminoglycans. The repair tissue structure was also examined with quantitative polarized light microscopy and indentation analysis of the cartilage stiffness. RESULTS: The ICRS grading indicated nearly normal repair tissue in 65% (10/17) after the autologous chondrocyte transplantation and 86% (7/8) after no repair at 3 months. At 1 year, the repair tissue was nearly normal in all cases in the spontaneous repair group and in 38% (3/8) in the chondrocyte transplantation group. In most cases, the cartilage repair tissue stained intensely for glycosaminoglycans and collagen type II indicating repair tissue with true constituents of articular cartilage. There was a statistical difference in the total histological scores at 3 months (P=0.028) with the best repair in the spontaneous repair group. A marked subchondral bone reaction, staining with toluidine blue and collagen type II, was seen in 65% of all animals. CONCLUSIONS: The spontaneous repair ability of full thickness cartilage defects of immature pigs is significant and periosteum or autologous chondrocytes do not bring any additional benefits to the repair.
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