Related Experiment Video
Updated: Aug 23, 2026
A Pre-Clinical Model of Synovitis Using Ex vivo Human Synovial Tissue with Preserved Function and Architecture
Published on: March 20, 2026
MMP profile in paired serum and synovial fluid samples of patients with rheumatoid arthritis
I Tchetverikov1, H K Ronday, B Van El
1TNO Prevention and Health, PO Box 2215, 2301 CE, Leiden, The Netherlands.
Objective:
To analyse matrix metalloproteinases (MMPs) and tissue inhibitor-1 of MMPs (TIMP-1) levels in the systemic circulation and synovial fluid (SF) of patients with RA and to compare these levels with inflammatory and collagen degradation markers.
Methods:
ProMMP-1, -2, -3, -8, -9, TIMP-1, levels of MMP/alpha(2)-macroglobulin complexes, and collagen degradation products were measured by sandwich ELISA, activity assays, and HPLC in paired SF and serum samples from 15 patients with RA and 13 with OA.
Results:
MMPs were higher in SF of patients with RA than in OA or controls. MMP levels in SF of patients with OA were higher than in controls. In serum, levels of proMMP-3, -8 and -9 were higher in patients with RA than in OA or controls, whereas only proMMP-8 and -9 were higher in serum of patients with OA than in controls. A strong correlation was seen between serum and SF levels of MMP-8 and -9 in RA. Increased levels of MMP/alpha(2)-macroglobulin complexes indicated an MMP/TIMP imbalance in serum and SF in RA. SF hydroxyproline correlated significantly with SF levels of proMMP-9 in RA.
Conclusions:
Systemic MMP-8 and -9 levels represent the situation in the inflamed joint; MMP-9 is likely to be involved in degradation of joint collagen. The hypothesis of MMP/TIMP imbalance in RA is strengthened.
Insights
Matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs (TIMP-1) are elevated in rheumatoid arthritis (RA) patients. Systemic MMP-8 and MMP-9 levels reflect joint inflammation, suggesting MMP-9 degrades joint collagen.
Area of Science:
- Biochemistry
- Immunology
- Rheumatology
Background:
- Rheumatoid arthritis (RA) involves complex inflammatory and degradative processes.
- Matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) play crucial roles in tissue remodeling and degradation.
Purpose of the Study:
- To analyze matrix metalloproteinases (MMPs) and tissue inhibitor-1 of MMPs (TIMP-1) levels in systemic circulation and synovial fluid (SF) of RA patients.
- To compare these levels with inflammatory and collagen degradation markers in RA, osteoarthritis (OA), and control groups.
Main Methods:
- Quantification of ProMMP-1, -2, -3, -8, -9, TIMP-1, MMP/alpha(2)-macroglobulin complexes, and collagen degradation products.
- Utilized sandwich ELISA, activity assays, and HPLC on paired SF and serum samples from 15 RA patients and 13 OA patients.
Main Results:
- MMP levels were significantly higher in SF of RA patients compared to OA or controls.
- Serum proMMP-3, -8, and -9 were elevated in RA patients versus OA or controls.
- Elevated MMP/alpha(2)-macroglobulin complexes indicated an MMP/TIMP imbalance in both serum and SF in RA.
Conclusions:
- Systemic MMP-8 and MMP-9 levels accurately represent the inflammatory state within the joint.
- MMP-9 is implicated in the degradation of joint collagen in RA.
- The findings strengthen the hypothesis of an MMP/TIMP imbalance in RA pathogenesis.