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Synovial fluids from infected joints contain active metalloproteinases and no inhibitory activity
T E Cawston1, L Weaver, R J Coughlan
1Rheumatology Research Unit, Addenbrooke's Hospital, Cambridge.
Abstract:
Serial samples of synovial fluid aspirated from two patients with septic arthritis were assayed for proteinases and proteinase inhibitors. Active metalloproteinases but no proteinase inhibitors were present in all samples taken prior to treatment. The levels of active metalloproteinases fell with time although proenzyme forms were still present in the fluids. Both alpha 2-macroglobulin and the tissue inhibitor of metalloproteinases were found in the septic synovial fluids after treatment commenced. It is proposed that the lack of inhibitors and the presence of active proteinases capable of digesting collagen, gelatin and proteoglycan accounts for the rapid loss of cartilage found in septic arthritis.
Insights
Septic arthritis involves active proteinases and a lack of inhibitors, leading to rapid cartilage damage. Treatment introduces proteinase inhibitors, reducing active enzymes in synovial fluid.
Area of Science:
- Biochemistry
- Rheumatology
- Orthopedics
Background:
- Septic arthritis causes rapid cartilage destruction.
- The role of proteinases and inhibitors in this process is not fully understood.
Purpose of the Study:
- To investigate the presence and activity of proteinases and their inhibitors in synovial fluid from septic arthritis patients.
- To correlate enzyme activity with disease progression and treatment response.
Main Methods:
- Serial synovial fluid samples were collected from two patients with septic arthritis.
- Samples were analyzed for active metalloproteinases and proteinase inhibitors using biochemical assays.
Main Results:
- Active metalloproteinases were detected in pre-treatment samples, with no detectable inhibitors.
- Metalloproteinase levels decreased over time post-treatment, though proenzyme forms persisted.
- Alpha 2-macroglobulin and tissue inhibitor of metalloproteinases were identified in post-treatment samples.
Conclusions:
- The absence of inhibitors and presence of active proteinases contribute to cartilage degradation in septic arthritis.
- Treatment initiation leads to the reappearance of proteinase inhibitors in synovial fluid.