MATRIX METALLOPROTEINASES AND TISSUE INHIBITORS OF METALLOPROTEINASESIN LOOSE ARTIFICIAL HIP JOINTS

The role of extracellular matrix metalloproteinase enzymes and the tis sue inhibitors of metalloproteinase in the periprostetic connective ti ssue matrix of loose artificial hip joints is reviewed, In the peripro sthetic granulomatous interface connective tissues between bone and im plants and inner cellular regenerating pseudocapsular tissues, matrix metalloproteinase 1, matrix metalloproteinase 2, matrix metalloprotein ase 3, matrix metalloproteinase-9, and membrane type 1 matrix metallop roteinase enzymes can be shown in the light of immunohistochemistry, e nzyme activity analysis, and messenger ribonucleic acid levels. Tissue inhibitors of metalloproteinase 1 and tissue inhibitors of metallopro teinase 2 also are found in the corresponding tissues, Analysis of mat rix metalloproteinase and tissue inhibitors of metalloproteinase inter action shows imbalance between the enzymes and the endogenous inhibito rs in favor of matrix metalloproteinase, This induces pathologic conne ctive tissue remodeling in the interface and pseudocapsule. The data s uggest that matrix metalloproteinase and tissue inhibitors of metallop roteinase system participate in the extracellular matrix degradation a nd tissue remodeling in artificial hip joints, and may contribute to t he periprosthetic weakening, implant loosening, and osteolysis around implants, More evidence for their active involvement is sought by inte rvention studies with type specific matrix metalloproteinase inhibitor s.