Investigation of microbial flora and defensin levels in deep periodontal pockets with different inflammation degrees

Expression and secretion of human gingival beta-defensins (hBDs) are prone to shifts in bacterial virulence and host inflammatory responses. The aim of this study was to profile gingival tissue levels of hBD-2 and hBD-3, in relation to clinical gingival inflammation, Porphyromonas gingivalis counts, and related protease activities. Gingival granulation tissue and subgingival plaque samples were collected from 21 periodontitis patients including 48 periodontal pocket sites with probing pocket depth of 5-7 mm and marginal, mild, or moderate to severe inflammation. Beta-defensin levels were determined by immünodetection, P. gingivalis counts with real-time polymerase chain reaction, and protease activities with fluorogenic substrates. Data were statistically analyzed by using Kruskal-Wallis, Mann-Whitney U, and Spearman correlation tests. In gingival tissues, hBD-2 and hBD-3 were found in dimeric forms. Subgingival plaque counts of P. gingivalis and related gingipain activity were increased, whereas no change was observed in hBD-2 and hBD-3 levels with the inflammation. Furthermore, negative correlations were found between gingival total protease activity and levels of hBD-2 and hBD-3. Elevated plaque counts of P. gingivalis and gingipain activity, but not hBDs, are related to gingival clinical inflammation. Negative correlations between the hBDs and total protease activity may indicate the degradation or inactivation of these antimicrobial peptides in progressed inflammation.