The effect of smoking on HBD-2 expression in chronic periodontitis

Background: Human beta defensin-2(HBD-2) is an epithelial-derived antimicrobial peptide which plays an important role in host defense mechanism against periodontopathic bacteria and functions as the linkage between innate and adaptive immunity.

Objective: This study investigated human beta defensin-2 (HBD-2) peptide expression in periodontal health and disease. To determine the effect of smoking on HBD-2 expression.

Methods: Gingival biopsies were obtained from 20 subjects with healthy gingiva and 20 patients with advanced periodontitis. Each group contained of 10 smoking and 10 nonsmoking subjects. All samples were categorized into 4 subgroups which were Nonsmoking-healthy(NH), Nonsmoking-Disease(ND), Smoking-Healthy(SH), Smoking-Disease(SD)tissues. All of the gingival tissues were prepared in frozen sections. The expression of HBD-2 was detected by immunohistochemistry, measured by the percentage of positive cells, and statistically analyzed.(ANOVA, Bonferroni's, p<0.05)

Results: All 40 samples demonstrated positive staining of HBD-2 which confined from the basal to the corneal layers of gingival epithelium. Significantly higher level of HBD-2 expression was found in the NH group as compared to the ND group(67.09%vs46.52%). (p<0.05) There was also a trend of lower expression of HBD-2 in SH group(54.75%) and SD group.(52.24%)

Conclusions: Higher level of HBD-2 expression in periodontal health suggests a protective role of HBD-2 in the host immune response to periodontal infection. Further investigation in larger sample size is needed for better understanding the negative effect of smoking on HBD-2 expression.