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Journal ArticleDOI

Biochemical and metabolic abnormalities in articular cartilage from osteo-arthritic human hips. II. Correlation of morphology with biochemical and metabolic data.

TL;DR: For thirty-two areas of cartilage from nine osteo-arthritic and four "normal" femoral heads a histologic-histochemical grade was assigned as an index of severity of the osteo -arthritic process.
Abstract: For thirty-two areas of cartilage from nine osteo-arthritic and four "normal" femoral heads a histologic-histochemical grade was assigned as an index of severity of the osteo-arthritic process. The DNA and hexosamine concentrations were determined as indicators of cell density and polysaccharide con
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Journal ArticleDOI
TL;DR: The OARSI cartilage OA histopathology grading system appears consistent and simple to apply as discussed by the authors, however, further studies are required to confirm the system's utility, as well as their reproducibility and validity.

1,813 citations

Journal ArticleDOI
TL;DR: A semi-quantitative scoring system that can be applied universally to instability, enzymatic, transgenic and spontaneous OA models may be a useful tool for both new and experienced scorers to sensitively evaluate models and OA mechanisms, and also provide a common paradigm for comparative evaluation across the many groups performing these analyses.

1,701 citations

Journal ArticleDOI
TL;DR: The data suggest that collagenase(s) produced by chondrocytes is (are) involved in the cleavage and denaturation of type II collagen in articular cartilage, that this is increased in OA, and that MMP-13 may play a significant role in this process.
Abstract: We demonstrate the direct involvement of increased collagenase activity in the cleavage of type II collagen in osteoarthritic human femoral condylar cartilage by developing and using antibodies reactive to carboxy-terminal (COL2-3/4C(short)) and amino-terminal (COL2-1/4N1) neoepitopes generated by cleavage of native human type II collagen by collagenase matrix metalloproteinase (MMP)-1 (collagenase-1), MMP-8 (collagenase-2), and MMP-13 (collagenase-3). A secondary cleavage followed the initial cleavage produced by these recombinant collagenases. This generated neoepitope COL2-1/4N2. There was significantly more COL2-3/4C(short) neoepitope in osteoarthritis (OA) compared to adult nonarthritic cartilages as determined by immunoassay of cartilage extracts. A synthetic preferential inhibitor of MMP-13 significantly reduced the unstimulated release in culture of neoepitope COL2-3/4C(short) from human osteoarthritic cartilage explants. These data suggest that collagenase(s) produced by chondrocytes is (are) involved in the cleavage and denaturation of type II collagen in articular cartilage, that this is increased in OA, and that MMP-13 may play a significant role in this process.

997 citations

Journal ArticleDOI
TL;DR: This review presents a summary of the hierarchical features for articular cartilage and diarthrodial joints and tables of known material properties for cartilage to summarize how the multi-scale interactions in articular Cartilage provide for its unique material properties and tribological characteristics.

886 citations

Journal ArticleDOI
TL;DR: The reaction patterns of chondrocytes in osteoarthritis can be summarized in five categories: proliferation and cell death (apoptosis); changes in synthetic activity and degradation; changes in phenotypic modulation of the articular chondROcytes; and formation of osteophytes.
Abstract: The reaction patterns of chondrocytes in osteoarthritis can be summarized in five categories: (1) proliferation and cell death (apoptosis); changes in (2) synthetic activity and (3) degradation; (4) phenotypic modulation of the articular chondrocytes; and (5) formation of osteophytes. In osteoarthritis, the primary responses are reinitiation of synthesis of cartilage macromolecules, the initiation of synthesis of types IIA and III procollagens as markers of a more primitive phenotype, and synthesis of active proteolytic enzymes. Reversion to a fibroblast-like phenotype, known as 'dedifferentiation', does not appear to be an important component. Proliferation plays a role in forming characteristic chondrocyte clusters near the surface, while apoptosis probably occurs primarily in the calcified cartilage.

758 citations