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Immunohistochemical analysis of type X‐collagen expression in osteoarthritis of the hip joint
Author(s) -
Boos Norbert,
Nerlich Andreas G.,
Wiest Irmagard,
von der Mark Klaus,
Ganz Reinhold,
Aebi Max
Publication year - 1999
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100170406
Subject(s) - osteoarthritis , cartilage , immunohistochemistry , pathology , extracellular matrix , collagen, type i, alpha 1 , medicine , type i collagen , type ii collagen , anatomy , chemistry , biochemistry , alternative medicine
Conflicting data have been reported on the spatial distribution of type X‐collagen expression in osteoarthritis, and no concise data exist on a possible correlation between type X‐collagen expression and clinical and radiological alterations. Well defined clinical and radiological data were compared with histopathological and immunohistochemical findings to investigate the expression of type‐X collagen in osteoarthritis of the hip joint. Femoral heads were obtained in toto from 11 patients undergoing routine hip arthroplasty for femoral neck fractures (n = 3) or osteoarthritis (n = 8) and from 13 patients (age: 12 days to 69 years) without any evidence of hip‐joint pathology. Whole coronal sections from the femoral head were decalcified for routine histology and immunohistochemical analysis with use of type‐specific monoclonal antibodies to type‐X collagen. Our results demonstrate that type‐X collagen is consistently found in osteoarthritic cartilage and is absent from normal adult cartilage (including the region of calcified cartilage). Except for the occurrence of type‐X collagen in the middle zone of articular cartilage in advanced stages of osteoarthritis, there is no specific change in the staining pattern or intensity for the collagen during osteoarthritis, particularly when the staining is related to clinical and radiological parameters. Hardly more than 20% of the extracellular matrix stained for type‐X collagen; therefore, we suggest that, in most cases, this type of collagen may not play a direct biomechanical role in the weakening of osteoarthritic cartilage but rather may contribute indirectly to a disturbance of the disc biomechanics by altering matrix‐molecule interaction. However, expression of type‐X collagen may indicate a change in chondrocyte phenotype that consistently coincides with the formation of chondrocyte clusters, one of the first alterations in osteoarthritis visible on histologic examination.