To evaluate whether matrix metalloproteinase 3 (MMP-3), a proteinase that is expressed in rheumatoid synovial tissue and shows potent activity in degrading the proteoglycan of cartilage, plays a pivotal role in the joint destruction seen in early rheumatoid arthritis (RA).
In a prospective study of patients with early RA, the relationship between the serum concentration of MMP-3, as determined by a sandwich enzyme immunoassay system, and the progression of joint destruction in patients with early RA, as measured by the Larsen radiologic score, was investigated.
Serum MMP-3 levels were elevated in the RA patients compared with healthy controls, not only in the late stage, but also in the early stage of the disease in patients whose duration of RA was <4 months. The serum MMP-3 level at entry into the study had a strong correlation with the Larsen score at 6 months and 12 months after entry (r = 0.58 and r = 0.49, respectively). Similarly, the serum MMP-3 level at 12 months and 24 months after entry showed a positive association with the Larsen score in the subsequent 6-12 months. Suppression of the serum MMP-3 level in the first year led to a decline in joint damage in the second year.
The serum concentration of MMP-3 is a useful marker for predicting bone damage in the early stage of RA, and the suppression of MMP-3 production may be an effective therapeutic approach for patients with early RA.