Associations Between Matrix Metalloproteinase-8 and -14 and Myeloperoxidase in Gingival Crevicular Fluid From Subjects With Progressive Chronic Periodontitis: A Longitudinal Study

Background: Matrix metalloproteinase (MMP)-8 is a central mediator in chronic periodontitis. MMP-8 can be activated by the cooperative action of otherMMPs such asMMP-14, reactive oxygen species, andmicrobial proteases. The aimof this study is to associate the levels, molecular forms, isoenzyme distribution, and degree of activation of MMP-8 and -14, myeloperoxidase (MPO), and tissue inhibitor of MMP (TIMP)-1 in gingival crevicular fluid (GCF) from patients with progressive periodontitis at baseline and after periodontal therapy. Methods: In this longitudinal study, GCF samples from active (n = 25) and inactive (n = 25) sites of subjects with periodontitis were screened at baseline for GCF levels of MMP-8 by immunofluorometric assay, of MMP-14 by specific activity assay, and of MPOandTIMP-1 by enzyme-linked immunosorbent assay.MMP-8 andMPOwere alsomeasuredafterperiodontal treatment. Molecular forms were determined by immuno-Western blot analyses and subjected to densitometric scanning and statistical analyses. Results: High MMP-8 and MPO levels and a strong MPO/ MMP-8 positive correlation were found in active and inactive sites at baseline. After treatment, decreases in MPO and MMP-8 were seen, except for active sites in which MMP-8 differences were not significant (P