Expression profiles of lipopolysaccharide-binding protein in subjects with chronic periodontitis

Abstract

Lipopolysaccharide-binding protein (LBP) is an acute-phase reactant that functions as a crucial molecule in innate host defense responses to bacterial challenge through neutralization of lipopolysaccharide (LPS) and activation of cellular responses. Little is known about the role of LBP in the pathogenesis of periodontal diseases. Objectives: This study was to investigate the expression profile of LBP in gingival tissues under various periodontal conditions. Methods: Gingival biopsies were collected from 24 chronic periodontitis patients who underwent periodontal surgery. The samples included 22 periodontal pocket tissues (PoT) and 13 adjacent healthy gingival tissues (HT-P). Seven gingival tissue samples were obtained from 7 periodontally healthy controls (HT-C). LBP was detected by immunohistochemistry method. Results: LBP expressed in 20 of 22 PoTs, 11 of 13 HT-Ps and all HT-Cs. The expression of LBP was mainly confined to the cytoplasm of granular and keratinized layers of gingival epithelium, spreading from the oral sulcular epithelium to oral epithelium with the expression density decreasing gradually from coronal to apical portion. LBP was also found occasionally on endothelial surfaces and/or inside the lumen of blood vessels in connective tissues. Conclusions: We for the first time found the frequent expression of LBP in the cytoplasm of granular and keratinized cells of gingival epithelia in both healthy and periodontitis subjects. LBP was also detected in blood vessels of connective tissues. These findings suggest that LBP may play a crucial role in chronic periodontitis via the local expression and systemic circulation pathways.