CATHEPSIN-B, ALPHA(2)-MACROGLOBULIN AND CYSTATIN LEVELS IN GINGIVAL CREVICULAR FLUID FROM CHRONIC PERIODONTITIS PATIENTS

Gingival crevicular fluid (GCF) was collected from 16 molar and premol ar sites in each of 20 chronic periodontitis patients before and after periodontal therapy using filter paper strips. These were eluted indi vidually into buffer for determination of cathepsin B and its endogeno us inhibitors, alpha(2)-macroglobulin and cystatin, Cathepsin B activi ty was assayed with a fluorogenic peptide substrate, alpha(2)-macroglo bulin by enzyme-linked immunosorbent assay and cystatin activity by in hibition of papain, Total amounts of enzyme and inhibitor per GCF samp le decreased after treatment and correlated positively with pocket dep th and gingival, bleeding and plaque indices, These comparisons were n early always statistically significant for pooled site data and someti mes so for mean patient values, The amounts of alpha(2)-macroglobulin and cystatin were greater than those of cathepsin B and surprisingly, enzyme and inhibitor levels correlated positively with each other. Exp eriments with purified reagents. however, demonstrated that the cathep sin B: alpha(2)-macroglobulin complex was still active against the low molecular weight substrate and that cystatin levels In GCF are probab ly insufficient to inhibit the enzyme substantially These factors may explain why GCF cathepsin B activity reflects the clinical status of p eriodontal lesions and has been identified in another study as a promi sing indicator of disease progression.