Evidence for metalloproteinase and metalloproteinase inhibitor imbalance in human osteoarthritic cartilage.

124

Levels of tissue inhibitor of metalloproteases (TIMP) and plasminogen activator (PA)/plasmin were measured and the distribution of PA was studied by immunohistochemical techniques in cartilage and synovium samples from dogs subjected to sectioning of the anterior cruciate ligament of their right knees and sham operation of their left knees (controls). Twenty-three animals were divided into 3 groups and killed at 2,4, or 8 weeks after surgery. The levels of PA and plasmin were found to be significantly elevated in the osteoarthritic (OA) knee cartilage and synovium at all times after surgery, except for levels of PA in the OA cartilage at 2 weeks. There was a positive correlation between the levels of PA and plasmin in the synovial membrane (r = 0.64, P < 0.001). In OA knees, the presence of high levels of total and active collagenase was detected in cartilage and in synovium. The levels of these 2 forms of collagenase showed a positive correlation both in cartilage (r = 0.65, P < 0.001) and in synovium (r = 0.77, P < 0.001). The levels of TIMP in cartilage from OA and sham operated knees were similar. Although the TIMP level was increased in the OA synovium, it was found 30, 1990. only in trace amounts in cartilage. Immunohistochemical studies revealed that both forms of PA, urokinasetype PA and tissue-type PA, and TIMP were present in OA tissues. In the synovium, they were found mainly in monocyte/macrophages, synovial lining cells, and blood vessel cells. In OA cartilage, PA was present only at the superficial level in chondrocytes and in cartilage matrix, whereas TIMP was present in chondrocyte lacunae throughout the full thickness of the cartilage. TIMP was also detected in the superficial level of cartilage from sham operated knees. The results of this study indicate that in OA tissues, there are conditions that favor the synthesis and activation of metalloproteases. PA and plasmin are likely to play an important role in the physiologic activation of metalloproteases, although they are probably not the only system involved in this process. The lack of increased TIMP levels in the OA cartilage, in the presence of increased metalloprotease activity, is also a possible contributing factor in the enzymatic degradation of this tissue.Osteoarthritis (OA) is a multifactorial disease in which several complex mechanisms lead to a progressive destruction of joints. The frequent involvement of diarthrodial, weight-bearing joints is largely responsible for the morbidity of OA. The primary changes seem to appear in the articular cartilage and involve both extrinsic and intrinsic factors. Among the latter, anatomic or mechanical disturbances may be of major importance in the development of OA (1). According to the mechanical factors involved in this disease, researchers have developed several experimental animal models of OA (2). One of the difficulties with many of these models is that the lesions created are often rapidly progressive and very severe.

Section: Discussionsupporting

confidence: 94%

Section: Imbalance Between the Mechanisms Of Activation And Inhibitiomentioning

confidence: 99%

Imbalance between the mechanisms of activation and inhibition of metalloproteases in the early lesions of experimental osteoarthritis

Pelletier

Mineau

Faure

et al. 1990

124

“…Stimulated aggrecan synthesis results in more aggrecan fragments carrying the 846 epitope (12). Higher synovial concentrations of matrix metalloproteinases (MMPs), such as MMP-1 and MMP-3, and proteinase activity after joint injury and in OA are consistent with the observed expression of these proteases in cartilage and synovium in these conditions (13)(14)(15)(16)(17). Good evidence exists for proteolytic de-gradation of joint cartilage aggrecan (3,(18)(19)(20).…”

mentioning

confidence: 74%

The release of crosslinked peptides from type II collagen into human synovial fluid is increased soon after joint injury and in osteoarthritis

Lohmander¹,

Atley²,

Pietka³

et al. 2003

234

165

Objective. To determine concentrations of crosslinked C-telopeptide fragments of type II collagen (CTX-II) in synovial fluid (SF) from patients with joint injury, osteoarthritis (OA), or other knee arthritides.Methods. Two study groups were used: a crosssectional group, which included healthy-knee volunteers (reference group [REF]) and patients with pseudogout (PPA), an anterior cruciate ligament tear with or without a meniscus tear (INJ), or primary knee OA (POA); and a longitudinal group, which included patients with arthroscopic cartilage changes or septic arthritis. CTX-II was quantified by competition enzyme-linked immunosorbent assay (ELISA) based on a monoclonal antibody that recognized the C-terminus of the peptide EKGPDP as a proteolytic neoepitope. Aggrecan fragments, matrix metalloproteinases 1 and 3, and tissue inhibitor of metalloproteinases 1 were determined by ELISAs.Results. Concentrations of CTX-II in SF were higher in patients with PPA, INJ, and POA than in the REF group (P < 0.001). After joint injury, mean levels of CTX-II in SF were increased above REF levels at all time intervals (P < 0.001), and were highest within hours after trauma. In those in the longitudinal study group with joint cartilage damage, variation coefficients for CTX-II were 81% (between patients) and 64% (within patient), monitored over 1 year. In a patient with septic arthritis, SF CTX-II increased at the onset of symptoms, and peaked 30-fold higher than the baseline. Concentrations of all biomarkers decreased with successful treatment.Conclusion. This is the first report to describe the release into SF of soluble molecular fragments specific for the degradation of mature, crosslinked, type II collagen (CII) in human OA and joint injury. The results provide strong evidence that the integrity of the CII network of cartilage is compromised soon after joint injury and in arthritis. This early degradation of CII may represent an important treatment target.Osteoarthritis (OA) and joint injury are characterized by remodeling and degradation of cartilage, bone, and other joint tissues. The normally very slow turnover rate of cartilage matrix (1) is increased, as observed by several techniques in both animal OA models and human OA. Phasic changes in both synthesis and degradation of collagen and other matrix molecules (2-6) are associated with altered tissue structure and material properties (7-9).Increased joint tissue turnover after injury and in OA can be detected by a release of molecules and molecular fragments into synovial fluid (SF), blood, and urine. For example, the stimulated synthesis of type II collagen (CII) results in higher levels of CII C-propeptide in SF (10,11). Stimulated aggrecan synthesis results in more aggrecan fragments carrying the 846 epitope (12). Higher synovial concentrations of matrix metalloproteinases (MMPs), such as MMP-1 and MMP-3, and proteinase activity after joint injury and in OA are consistent with the observed expression of these

“…Since the level of active MMP is a key limiting factor in the degradation of cartilage macromolecules, the regulation of MMP activity seems to be of utmost importance in the pathophysiology of OA (3,4). The activation of MMP in OA tissues may be related to an increase in their physiologic activators and/or a decrease in their physiologic inhibitors (3,(7)(8)(9)(10). The regulation of the synthesis of these enzymes may occur at several levels; the mechanisms are not yet fully understood.…”

mentioning

confidence: 99%

Effects of tenidap on canine experimental osteoarthritis i. morphologic and metalloprotease analysis

Fernandes

Martel‐Pelletier

Otterness

et al. 1995

Objective. To examine the effects of tenidap and diclofenac on osteoarthritic lesions and metalloprotease activity in experimental osteoarthritis (OA).Methods. The anterior cruciate ligament of the right stifle joint of 25 mongrel dogs was sectioned by a stab wound. Seven dogs received no treatment, 6 were treated with oral omeprazole (20 mg/day), another 6 were treated with diclofenac (0.25 mg/kg/twice daily) plus omeprazole (20 mg/day), and 6 received oral tenidap (3 mg/kg/twice daily) plus omeprazole (20 mg/ day). The dogs received medication for 8 weeks; all dogs were killed at the end of this period. Eight normal dogs were used as controls. Lesions were evaluated macroscopically for the incidence and size of osteophytes and the area and grade of cartilage erosions on the condyles and plateaus, along with histologic evaluation of the severity of the cartilage lesions and synovial inflammation. Stromelysin and collagenase activities and the collagenase messenger RNA (mRNA) level were measured in cartilage and synovial membrane.Results. Compared with the untreated or omeprazole-treated OA groups, the dogs treated with tenidap exhibited significant reduction in the incidence (P 5 0.001) and size (P 5 0.0001) of osteophytes. Tenidap also significantly decreased the size and grade of cartilage macroscopic lesions, as well as the histologic severity of cartilage lesions on both condyles and plateaus. The histologic severity of synovial inflammatory reaction was also significantly reduced (P I 0.003) in the tenidap group. Tenidap markedly decreased stromelysin and collagenase activity in both cartilage (stromelysin P I 0.003; collagenase P I 0.01) and synovial membrane (stromelysin P 5 0.003; collagenase P 5 0.005). Moreover, tenidap also decreased the collagenase mRNA level in cartilage (P 5 0.005) and synovial membrane (P 5 0.002). Diclofenac slightly reduced the incidence and size of osteophytes and cartilage lesions, but these changes were not statistically significant. Diclofenac had no effect on the severity of synovial inflammation, metalloprotease activity, or collagenase expression.Conchsion. This study showed that tenidap had a more potent anti-osteoarthritic effect than diclofenac in this model. The effect of the drug in suppressing metalloprotease synthesis, a process known to play a major role in the pathophysiology of osteoarthritic lesions, may explain its mechanism of action.Transection of the anterior cruciate ligament of the dog knee leads to articular changes which resemble the morphologic and biochemical changes seen in human osteoarthritis (OA) (1-3). Cartilage lesions are probably related to mechanical as well as biochemical factors, including the enzymatic cleavage of matrix macromolecules (4). Matrix metalloproteases (MMP), such as collagenase and stromelysin, have been found to be significantly increased in OA cartilage and synovial membrane, in humans as well as in the experimental dog model (4-6). It is becoming more and more