Rapidly destructive osteoarthritis (OA) of the hip is an uncommon subset of OA that affects mainly elderly women. Previous studies indicate that elevated levels of matrix metalloproteinases (MMPs) are produced within the tissue of patients with the condition. In the present study, we sought to determine whether serum and plasma levels of MMPs and tissue inhibitors of metalloproteinases (TIMPs) are also elevated.
Blood samples were obtained from 16 patients with rapidly destructive hip OA and from 20 patients with OA before total hip arthroplasty was performed. Synovial specimens were obtained during surgery. Synovial fibroblasts that had migrated sufficiently from explants were subcultured in vitro for 72 hours after confluency, and harvested supernatants were collected. Blood, tissue samples, and fibroblasts were assayed for MMPs 1, 2, 3, and 9, and TIMPs 1 and 2 by sandwich enzyme immunoassay.
In blood samples, the levels of MMP-3 and MMP-9 in the group with rapidly destructive hip OA were significantly higher than the normal range and were also significantly higher than those in the OA group. In tissue samples, the levels of MMP-1, MMP-3, MMP-9, and TIMP-1 in the group with rapidly destructive hip OA were significantly higher than those in the OA group.
The results of this study show that serum and plasma levels of MMP-3 and MMP-9 are significantly increased in patients with rapidly destructive hip OA. Significantly large amounts of these MMPs produced in synovial tissues within the hip joint could contribute in part to elevation of blood levels. Detection of increased levels of MMP-3 and MMP-9 in patients with painful, disabling hip OA may be of diagnostic value for rapidly destructive hip OA.