Synovial fluid analysis of two groups of proteoglycan epitopes distinguishes early and late cartilage lesions.
OBJECTIVE
To investigate whether fragmentation of proteoglycans in arthritis results in domains that have different levels of release from cartilage at different stages of the disease.


METHODS
Two regions of the proteoglycan, the hyaluronan-binding region and the glycosaminoglycan-rich region of the core protein, were measured, by immunoassay, in knee joint synovial fluids of patients with rheumatoid arthritis or reactive arthritis.


RESULTS
Synovial fluid concentrations of the glycosaminoglycan-rich region were highest in rheumatoid arthritis patients who had little cartilage damage as determined by radiography, whereas release of the hyaluronan-binding region predominated in patients with advanced cartilage destruction. In reactive arthritis, release of the glycosaminoglycan-rich region predominated.


CONCLUSIONS
These findings indicate that the hyaluronan-binding region is initially retained in the tissue during the development of cartilage destruction. The combined analysis of these markers offers a new avenue for assessment of the degree of cartilage damage in arthritis.
Saxne
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Department of Rheumatology, Lund University, Sweden.
Heinegård
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D000328:Adult; D000368:Aged; D016918:Arthritis, Reactive / Q000378:metabolism*; D001172:Arthritis, Rheumatoid / Q000378:metabolism*; D002356:Cartilage / Q000378:metabolism* / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D006820:Hyaluronic Acid / Q000378:metabolism; D008875:Middle Aged; D011509:Proteoglycans / Q000276:immunology / Q000378:metabolism*; D013582:Synovial Fluid / Q000378:metabolism*; D013997:Time Factors
D000939:Epitopes; D006025:Glycosaminoglycans; D011509:Proteoglycans; D006820:Hyaluronic Acid