| 1. |
- Haapala, Jussi, et al.
(author)
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Coordinated regulation of hyaluronan and aggrecan content in the articular cartilage of immobilized and exercised dogs.
- 1996
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In: Journal of Rheumatology. - : Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 23:9, s. 1586-1593
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To study the influence of joint loading and immobilization on articular cartilage hyaluronan concentration and histological distribution in the knee joints of young dogs subjected to 11 weeks' immobilization by splinting, and 15 weeks' running exercise at a rate of 40 km/day.METHODS: The amount of hyaluronan in articular cartilage was determined by a competitive binding assay using a biotinylated hyaluronan binding complex (HABC) of aggrecan and link protein. Histologic sections were stained for the localization of hyaluronan with the HABC probe. Extracted proteoglycans were characterized by sodium dodecyl sulfate agarose gel electrophoresis.RESULTS: Immobilization significantly reduced the concentration of hyaluronan in all sites studied (tibial and femoral condyles, patellar surface of femur). The proportion of hyaluronan to total uronic acid (mainly from aggrecan) remained unchanged because of a concurrent decrease in aggrecan. The ratio of hyaluronan and aggrecan remained constant also in runners. The staining pattern of free hyaluronan in the tissue sections and the electrophoretic mobility of the extracted proteoglycans were not affected by the different loading regimes.CONCLUSION: Reduced joint loading due to splint immobilization significantly decreases both hyaluronan and aggrecan in the articular cartilage. The remarkably parallel changes in aggrecan and hyaluronan content suggest that joint loading exerts a coordinated influence on their metabolism.
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| 2. |
- Inkinen, Ritva, et al.
(author)
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Relative increase of biglycan and decorin and altered chondroitin sulfate epitopes in the degenerating human intervertebral disc.
- 1998
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In: Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 25:3, s. 506-514
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Journal article (peer-reviewed)abstract
- OBJECTIVE: Proteoglycans are major components of the extracellular matrix of the intervertebral disc. They are vital for the biomechanical properties of the tissue, and are subject to changes in disc degeneration. We aimed to further define these changes and their relationship to normal aging.METHODS: Normal discs (age 13-53 years, n = 6) were analyzed from 5 different sites across the sagittal anterior-posterior direction. Degenerated anterior annulus fibrosus was collected from 7 patients aged 39-46 years. Extracted proteoglycans were separated using agarose and polyacrylamide gel electrophoresis and detected with toluidine blue staining and Western blotting.RESULTS: The center of the disc showed the highest level of total proteoglycans, but lowest levels of decorin and biglycan. Western blots displayed reduced signal for both glycanated and nonglycanated biglycan and decorin after adolescence, while an increased signal of biglycan was observed in degenerated annuli. The 7D4(-) and 3B3(-) epitopes on native chondroitin sulfate chains were present in the large proteoglycans of intervertebral discs, but their signal intensity had no correlation to degeneration. Chondroitinase ABC digestion of the blots brought up 7D4(+) signal in the small proteoglycans of degenerated, but not in healthy tissue. Decrease or total loss of 2B6(+) epitope (indicating 4-sulfated stubs of chondroitin sulfate chains) were found in the large proteoglycans of all degenerated annuli.CONCLUSION: Human intervertebral disc degeneration involves the accumulation of decorin and biglycan relative to other uronic acid containing proteoglycans, the disappearance of 4-sulfated core region in aggrecan-like large proteoglycans, and the emergence of a core structure in the chains of small proteoglycans reacting with the 7D4 antibody; these findings indicate a fundamental alteration in matrix properties that may contribute to the pathogenesis of the disease.
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| 3. |
- Lammi, Mikko, 1961-, et al.
(author)
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Undersulfated chondroitin sulfate does not increase in osteoarthritic cartilage.
- 2004
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In: Journal of Rheumatology. - : Journal of Rheumatology. - 0315-162X .- 1499-2752. ; 31:12, s. 2449-2453
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To test whether there is undersulfation of chondroitin sulfate in osteoarthritic bovine articular cartilage to support the hypothesis that sulfate deficiency is involved with the development of osteoarthritis.METHODS: Cartilage samples from bovine patellae (n = 32) were divided into 3 groups based on their osteoarthritic progression, as assessed by modified Mankin score. Uronic acid contents of the samples were determined. Fragmentation of the proteoglycans due to proteolytic processing was estimated with agarose gel electrophoresis. The molar ratios of chondroitin sulfate isoforms in the extracted proteoglycans were determined with fluorophore-assisted carbohydrate electrophoresis.RESULTS: Loss of proteoglycans and accumulation of tissue water was evident in groups II and III, and progressive OA increased heterogeneity of aggrecan population in groups II and III. Importantly, the molar ratio of nonsulfated disaccharide was decreased in the osteoarthritic articular cartilage.CONCLUSION: The structure of chondroitin sulfate in degenerated bovine cartilage did not support the hypothesis that sulfate depletion is present in osteoarthritic joint.
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