Objective. To quantify stromelysin and collagenase in synovial fluid (SF) from patients with rheumatoid arthritis (RA) or traumatic knee injury.Methods. Stromelysin and collagenase were measured in the SF of 33 patients with RA or pttraumatic knee injury, using specific double-antibody sandwich enzyme-linked immunosorbent assays. Stromelysin was fractionated from representative SF, and the molecular form was identilied by immunoblot analysis.Results. The stromelysin concentration was -20-fold higher than the collagenase concentration in the fluids from patients with RA and -8-fold higher in the fluids from patients with traumatic iaury. For both metalloproteinases, there was a higher enzyme concentration in RA SF than in the SF from patients with trauma (stromelysin 40.1 f 26 pg/ml [mean f SDI in RA SF, 8.5 +: 15 d m l in trauma SF; collagenase 2.2 f 3.3 pg/ml in RA SF, 1.1 f 2.3 pg/ml in trauma SF).The majority of the stromelysin within the SF bound to reactive red-agarose and was identified as prostrome-

Objective. To determine the effects of stromelysin treatment on biochemical, histologic, and swelling characteristics of intact cartilage explants and to correlate these effects with changes in the functional physical properties of the tissue. Methods. Bovine articular cartilage explants were cultured for up to 3 days in the presence or absence of recombinant human stromelysin (SLN). Damage to matrix proteoglycans and collagens was assessed and characterized by N‐terminal sequencing and Western blot analysis, respectively. Explants were mechanically tested to assess the ability of the tissue to withstand cyclic and static compressive loads. Results. Treatment with SLN resulted in a time‐and dose‐dependent loss of proteoglycans from cartilage explants, with significant loss seen after 3 days of exposure to 20 nM SLN. Histology indicated that initial loss of proteoglycans occurred in regions near the tissue surface and proceeded inward with increasing time of SLN exposure. SLN treatment resulted in degradation of matrix collagen types IX and II, and a concomitant increase in tissue swelling. This matrix degradation resulted in severe alterations in functional physical properties of the tissue, including compressive stiffness. The initial, focal loss of proteoglycans that resulted from SLN treatment was most accurately detected with highfrequency streaming potential measurements. Conclusion. Exposure of intact cartilage to SLN caused specific, molecular‐level degradation of matrix molecules, which resulted in changes in the swelling behavior and marked deterioration of functional physical properties of the tissue.

Carboxyalkyl peptides containing a biphenylylethyl group at the P1' position were found to be potent inhibitors of stromelysin-1 (MMP-3) and gelatinase A (MMP-2), in the range of 10-50 nM, but poor inhibitors of collagenase (MMP-1). Combination of a biphenylylethyl moiety at P1', a tert-butyl group at P2', and a methyl group at P3' produced orally bioavailable inhibitors as measured by an in vivo model of MMP-3 degradation of radiolabeled transferrin in the mouse pleural cavity. The X-ray structure of a complex of a P1-biphenyl inhibitor and the catalytic domain of MMP-3 is described. Inhibitors that contained halogenated biphenylylethyl residues at P1' proved to be superior in terms of enzyme potency and oral activity with 2(R)-[2-(4'-fluoro-4-biphenylyl)ethyl]-4(S)-n-butyl-1,5-pentane dioic acid 1-(alpha(S)-tert-butylglycine methylamide) amide (L-758,354, 26) having a Ki of 10 nM against MMP-3 and an ED50 of 11 mg/kg po in the mouse pleural cavity assay. This compound was evaluated in acute (MMP-3 and IL-1 beta injection in the rabbit) and chronic (rat adjuvant-induced arthritis and mouse collagen-induced arthritis) models of cartilage destruction but showed activity only in the MMP-3 injection model (ED50 = 6 mg/kg iv).

No abstract