Interactions of granulocyte proteases with inhibitors in rheumatoid arthritis.

Abstract

Cumulative evidence indicates that articular destruction in rheumatoid arthritis (RA) might be mediated by proteolytic enzymes1,2,3. The hypothesis of enzymatic degradation is emphasized by the presence in the arthritic joint of a multitude of proteolytic enzymes with potential ability to attack the macromolecules of cartilage matrix. These enzymes can originate from nearly all cell types found in the inflamed joint as proliferating synovial lining cells,4 polymorphonuclear leucocytes (PMNs)5, 6invading the joint space and macrophage-like cells7, 8infiltrating the synovial membrane. Released extracellularly, several of these enzymes have their optimum activity at the neutral pH prevailing within the arthritic joint and the concerted action of these neutral proteases implies a considerable destructive potential. One reason, however, for doubting the role of these enzymes in articular deterioration is the control mechanism exerted by the protease inhibitors present in the synovial fluid (SF).9,10,11 KeywordsRheumatoid ArthritisNeutral ProteaseArthritic JointInhibitory CapacityRheumatoid Synovial FluidThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.