Increased collagenase activity in human rheumatoid meniscus

Validation of a rapid collagenase activity detection technique based on fluorescent quenched gelatin with synovial fluid samples

BACKGROUND

Measuring collagenase activity is crucial in the field of joint health and disease management. Collagenases, enzymes responsible for collagen degradation, play a vital role in maintaining the balance between collagen synthesis and breakdown in joints. Dysregulation of collagenase activity leads to joint tissue degradation and diseases such as rheumatoid arthritis and osteoarthritis. The development of methods to measure collagenase activity is essential for diagnosis, disease severity assessment, treatment monitoring, and identification of therapeutic targets.

RESULTS

This study aimed to validate a rapid collagenase activity detection technique using synovial fluid samples. Antibody microarray analysis was initially performed to quantify the levels of matrix metalloproteinase-9 (MMP-9), a major collagenase in joints. Subsequently, the developed gelatin-based test utilizing fluorescence measurement was used to determine collagenase activity. There was a significant correlation between the presence of MMP-9 and collagenase activity. In addition, Lower Limit of Detection and Upper Limit of Detection can be preliminary estimated as 8 ng/mL and 48 ng/mL respectively.

CONCLUSIONS

The developed technique offers a potential point-of-care assessment of collagenase activity, providing real-time information for clinicians and researchers. By accurately quantifying collagenase activity, healthcare professionals can optimize patient care, improve treatment outcomes, and contribute to the understanding and management of joint-related disorders. Further research and validation are necessary to establish the full potential of this rapid collagenase activity detection method in clinical practice.

Anti-inflammatory effects of continuous passive motion on meniscal fibrocartilage

Motion-based therapies have been applied to promote healing of arthritic joints. The goal of the current study was to determine the early molecular events that are responsible for the beneficial actions of motion-based therapies on meniscal fibrocartilage. Rabbit knees with Antigen-Induced-Arthritis (AIA) were exposed to continuous passive motion (CPM) for 24 or 48 h and compared to immobilized knees. The menisci were harvested and glycosaminoglycans (GAG), interleukin-1beta (IL-1beta), matrix metalloproteinase-1 (MMP-1), cyclooxygenase-2 (COX-2), and interleukin-10 (IL-10) were determined by histochemical analysis. Within 24 h, immobilized knees exhibited marked GAG degradation. The expression of proinflammatory mediators MMP-1, COX-2, and IL-1beta was notably increased within 24 h and continued to increase during the next 24 h in immobilized knees. Knees subjected to CPM revealed a rapid and sustained decrease in GAG degradation and the expression of all proinflammatory mediators during the entire period of CPM treatment. More importantly, CPM induced synthesis of the anti-inflammatory cytokine IL-10. The results demonstrate that mechanical signals generated by CPM exert potent anti-inflammatory signals on meniscal fibrochondrocytes. Furthermore, these studies explain the molecular basis of the beneficial effects of CPM observed on articular cartilage and suggest that CPM suppresses the inflammatory process of arthritis more efficiently than immobilization.

The effect of alpha-2 macroglobulin on the healing of ruptured anterior cruciate ligament in rabbits

To investigate the effect of modification of biological environmental conditions, one of the factors influencing the healing of anterior cruciate ligament rupture, we performed experimental anterior cruciate ligament ruptures on New Zealand rabbits. After experimental rupture, intra-articular alpha-2 macroglobulin was injected into the knees of the rabbits in the experiment group to prevent structural changes resulting from the enzymatic reactions in the ruptured anterior cruciate ligament. At the end of 10th day of the experiment, we observed that the anterior cruciate ligaments in the experiment group had retained their prerupture brightness and volume when compared with the control group in which intraarticular alpha-2 macroglobulin had not been injected. We also noted that the anterior cruciate ligaments in the experiment group had not retracted or swollen, the incision sites were regular and clean, and they did not show any signs of degeneration. In the histological examination, the anterior cruciate ligaments in the control groups showed disruption of the collagen network and a significant diminution in number of fibroblasts and fibrocytes (p <.001). At the end of this study, we concluded that the necessary conditions for the healing and repair of ruptured anterior cruciate ligament could exist if the enzymatic and biological environments were under control.

Cellular repopulation of deep-frozen meniscal autografts: an experimental study in the dog

This study evaluated the cellular repopulation of deep-frozen meniscal autografts. Medial menisci of adult dogs were excised, deep-frozen in liquid nitrogen (-196 degrees C) for 10 min, and orthotopically reimplanted into the joint. Deep-freezing was found to effectively kill all the cells within the meniscus as determined by the absence of Na(2)35SO4 incorporation. Following orthotopic replacement within the knee joint, menisci were repopulated with cells that seemed to originate from the adjacent synovium. These cells migrated over the surface of the meniscus and began to invade the deeper layers of the tissue. However, even after 6 months, the central core of the meniscus remained acellular. While the new cells appeared to modulate into cells that are similar in appearance to meniscal fibrochondrocytes, the exact phenotypic expression of these newly differentiated cells has yet to be determined. Histological alterations, as manifested by a loss of normal orientation of the collagen architecture of the superficial layers of the meniscus; was evident at 6 months and suggests that a remodeling phenomenon may be associated with the cellular repopulation. While biomaterial studies have not been carried out on these specimens, the morphologic alterations observed in the collagen orientation would suggest a possible alteration in the material properties of the repopulated meniscus. The clinical implication of this study is that the structural remodeling associated with the cellular repopulation of deep-frozen meniscal allografts may make the transplanted meniscus more susceptible to injury.

Substrate specificity and activation mechanisms of collagenase from human rheumatoid synovium

Substrate specificity studies of collagenase extracted from human rheumatoid synovium suggest that synovial pannus tissue overlying articular cartilage may not be particularly active in degradation of cartilage type II collagen, which, considering the poor inherent healing capacity of the articular hyaline cartilage, may exert a protective function against inadvertant tissue damage. Rheumatoid synovial tissue was also used to establish synovial fibroblast cell lines. Treatment of these cells in monolayer cultures with IL-1 leads to collagenase gene activation, increased collagenase production and an almost complete autoactivation of secreted collagenase. Interleukin-1 also activated stromelysin gene suggesting this as a possible mechanism effecting autoactivation. Latent human fibroblast and macrophage collagenase purified from culture medium were efficiently activated by phenylmercuric chloride but also by gold thioglucose, gold sodium thiomalate and HCIO. These new observations support the Cys73 switch activation mechanism. In contrast to neutrophil collagenase, the activation by gold(I) compounds and HCIO was associated with a change in the apparent molecular weight of the fibroblast procollagenase. In addition, gold(I) compounds rendered collagenase more susceptible to thermal denaturation. Thus the fibroblast-type interstitial collagenase, probably derived from fibroblast- and macrophage-like synoviocytes, seems to provide the predominant collagenolytic potential in human rheumatoid synovial tissue. Furthermore, the conditions in synovitis tissue may be such as to favor at least initial activation of collagenase synthesized and secreted in situ.

Acute hemarthrosis: a histological, biochemical, and biomechanical correlation of early effects on the anterior cruciate ligament in a rabbit model

The early histological, biochemical, and biomechanical characteristics of the anterior cruciate ligament (ACL) were determined in a rabbit model of acute hemarthrosis. The ACLs of 19 rabbits were given seven consecutive daily knee injections of 2 ml of fresh autologous blood, and then compared to contralateral ACLs from control knees injected with 2 ml of lactated Ringer's solution daily for 7 days. The rabbits were then sacrificed. Synovial proliferation with iron deposition within synoviocytes was observed; however, the architecture of the ACL was maintained. Additionally, the total collagen content, collagenase activity, and biomechanical properties of the ACL were unaltered.

Injury of the anterior cruciate ligament: the role of collagenase in ligament degeneration

Rapid degeneration of the anterior cruciate ligament (ACL) has been observed following acute ACL rupture. An understanding of this process might explain some of the poor clinical results of primary ACL repair. We created a surgical rabbit model of acute ACL injury and developed an in vitro assay for collagenase activity in the ACL and menisci. Microscopic evaluation revealed a rapidly degenerative process in injured ACLs, with loss of cellularity and matrix organization. This was associated with a significant increase in collagenase activity and a decrease in total collagen of the injured ACLs as compared with sham-operated controls. These findings confirm the observation that cut ACL ligament ends rapidly degenerate. This degenerative process might be partly due to a response of cells intrinsic to the ACL to injury. Left unchecked, this process may be detrimental to surgical attempts for primary ACL repair.

Latent human leukocyte collagenase can be activated by gold thioglucose and gold sodium thiomalate, but not by auranofin

Gold thioglucose and gold sodium thiomalate were shown to be potent activators of latent human leukocyte collagenase. No activation by auranofin was noted. The activation may proceed through the action of gold on the essential sulfhydryl groups of latent enzyme and, thereby, mimick the action of the known organomercurial activators.