BIOCHEMICAL-ALTERATIONS IN INFLAMMATORY PERIODONTAL-DISEASES .1. POLY(ADP-RIBOSE) SYNTHETASE-ACTIVITY IN GINGIVA AND GINGIVAL FIBROBLASTS FROM HUMANS WITH PERIODONTITIS

Periodontal diseases are characterized in part by generation of oxygen free radicals, which can cause breaks in cellular DNA strands. Repair of damaged DNA is dependent upon the synthesis of poly(ADP-ribose)(PA DPR) catalyzed by PADPR synthetase, an enzyme known to be activated by the broken ends of DNA strands. We measured the activities of PADPR s ynthetase and of PADPR glycohydrolase, which degrades PADPRS, in gingi val biopsy specimens from 16 sites with adult periodontitis and 12 cli nically healthy control sites. The results indicated that sites with p eriodontitis displayed markedly reduced PADPR synthetase activity comp ared with healthy control sites, whereas PADPR glycohydrolase activity was not changed. The mean specific activity of PADPR synthetase for t he diseased specimens was one-sixth of that of the healthy specimens ( p < 0.001). The PADPR synthetase activity was negatively correlated wi th the Gingival Index (r(s) = -0.60), pocket depth (r(s) = -0.70) and bleeding upon probing (r(s) = -0.72). Cultured fibroblasts derived fro m clinically characterized healthy and diseased gingival sites reflect ed similar patterns of enzyme activity. The mean specific activity of PADPR synthetase for the diseased-site cultures (n = 9) was 56 +/- 7% (p < 0.001) of the cultures from healthy control sites (n = 6). These results suggest that a reduced level of PADPR synthetase activity is a ssociated with increased inflammation and periodontal destruction, and that the ability to synthesize PADPR is compromised in adult periodon titis.