The Mechanisms Of Cartilage Catabolism

Jt, Dingle

doi:10.1007/978-3-0348-7684-1_4

Cited by 2 publications

(3 citation statements)

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“…The first group should have a maximum activity at physiological pH to degrade the interterritorial matrix, and is likely comprised mainly of neutral metalloand serine proteases. The second group of enzymes should have maximum activity at intra-or pericellular pH, which is in the acid range (10). Among them, cysteine proteases (5) and acid metalloproteases (8,23) are likely candidates.…”

Section: Discussionmentioning

confidence: 99%

“…These changes often occur in the pericellular area around the chondrocytes (22,27), where the matrix pH is in the acid range (10). At first, it was believed that cathepsin D was the prime instigator of degradation in this area (28); however, in the OA process, this enzyme did not appear to play a role (13).…”

mentioning

confidence: 98%

“…Osteoarthritis (OA) is characterized by a progressive degradation of the major extracellular matrix macromolecules, collagen and proteoglycans, as shown by early ultrastructural and microscopic changes in the cartilage. These changes often occur in the pericellular area around the chondrocytes (22,27), where the matrix pH is in the acid range (10). At first, it was believed that cathepsin D was the prime instigator of degradation in this area (28); however, in the OA process, this enzyme did not appear to play a role (13).…”

mentioning

confidence: 99%

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Cathepsin B and cysteine protease inhibitors in human osteoarthritis

Martel‐Pelletier

Cloutier

Pelletier

1990

Journal Orthopaedic Research

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The aim of this study was to determine the involvement of cathepsin B and its inhibitors in the proteolytic degradation of human osteoarthritic (OA) tissue. The characteristics of the cathepsin B found in both normal and OA cartilage and synovium were similar to those of the lysosomal cathepsin B. Two inhibitors of cysteine proteases were found with a molecular weight of 67,000 and 16,000 Da. The cartilage cathepsin B level of OA specimens (54.8 +/- 7.3 units/micrograms of DNA) was greater than the controls (39.8 +/- 3.2 units/micrograms of DNA). Mild-moderate graded samples (78.1 +/- 12.0 units/micrograms of DNA) had significantly higher levels of enzyme activity than the severely graded ones (31.4 +/- 3.9 units/micrograms of DNA, p less than 0.001) and controls (p less than 0.01). Compared to controls (2.3 +/- 0.4 units/mg of tissue w.w.), cysteine protease inhibitory activity in OA cartilage was decreased in specimens with severe lesions (1.5 +/- 0.2 units/mg of tissue). This was particularly noted in patients who had not received steroid injections (1.2 +/- 0.3 units/mg of tissue, p less than 0.05). In OA synovia, the cathepsin B level was greater (40.7 +/- 7.4 units/mg of tissue w.w., p less than 0.02) than in the controls (13.6 +/- 3.7 units/mg of tissue). The cysteine protease inhibitory activity was similar in OA synovium (1.7 +/- 0.2 units/mg of tissue w.w.) and in controls (1.5 +/- 0.3 units/mg of tissue). This data demonstrated an imbalance between the levels of cathepsin B and cysteine protease inhibitors in OA tissue. A decrease of specific inhibitors could be an important contributing factor, particularly in more severe lesions.

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