Levels of high-mobility group box-1 in gingival crevicular fluid in nonsmokers and smokers with chronic periodontitis

Abstract

Background/Purpose: High-mobility group box-1 (HMGB1), a proinflammatory cytokine, plays a role in inflammatory disorders. Smoking is a well-established risk factor for periodontal disease. The aim of this study was to compare the levels of HMGB1 in the gingival crevicular fluid from periodontally healthy nonsmokers, chronic periodontitis nonsmokers, and chronic periodontitis smokers. Furthermore, the relationship between levels of HMGB1 and periodontal parameters was examined. Methods: Periodontal parameters of 17 nonsmokers with chronic periodontitis, nine smokers with chronic periodontitis, and nine periodontally healthy nonsmokers were examined. Gingival crevicular fluid samples were collected, and the levels of HMGB1 were analyzed using the enzyme-linked immunosorbent assay. Results: The median level of HMGB1 was statistically significantly higher in chronic periodontitis nonsmokers (37.5 ng/mL) than in chronic periodontitis smokers (9.5 ng/mL) and periodontally healthy nonsmokers (3.7 ng/mL). There was no significant difference in the levels of HMGB1 between chronic periodontitis smokers and periodontally healthy nonsmokers. Levels of HMGB1 were positively correlated with plaque index, gingival index, probing depth, and clinical attachment level of nonsmokers. However, no significant correlations were found between levels of HMGB1 and all periodontal parameters examined in chronic periodontitis smokers. Conclusion: Chronic periodontitis nonsmokers had elevated levels of HMGB1 in gingival crevicular fluid. Moreover, the levels of HMGB1 were correlated with severity of periodontitis. Chronic periodontitis smokers exhibited lower levels of HMGB1 than chronic periodontitis nonsmokers. Further research is needed for understanding the role of HMGB1 in smoking and pathogenesis of periodontitis. Keywords: gingival crevicular fluid, high-mobility group box-1, periodontitis, smoking