The actin-bundling protein L-plastin: a novel local inflammatory marker associated with periodontitis.

BACKGROUND AND OBJECTIVE: L-plastin, an actin-bundling protein, is exclusively expressed in leukocytes and plays a crucial role in immune-mediated events. Periodontitis is a common infectious inflammatory disease that destroys the tooth-supporting tissues. Recent findings using proteomic technologies have demonstrated that L-plastin is one of the few molecules consistently present in the inflammatory exudate of the gingiva in periodontal disease, but not in health. Therefore, this study aimed to investigate in detail the local and systemic role of this molecule in different forms of periodontitis. MATERIAL AND METHODS: A total of 61 subjects who met the inclusion/exclusion criteria were recruited, including 21 with chronic periodontitis, 20 generalized aggressive periodontitis and 20 nonperiodontitis control subjects. Gingival tissue biopsies, gingival crevicular fluid, as well as serum and saliva, were obtained. Immunohistochemistry and quantitative real-time PCR were employed to evaluate the localization and mRNA expression, respectively, of L-plastin. L-plastin levels in gingival crevicular fluid, saliva and serum were measured using ELISA. Statistical analysis was performed using nonparametric methods. RESULTS: Subjects with chronic periodontitis and generalized aggressive periodontitis exhibited significantly higher tissue L-plastin gene expression and gingival crevicular fluid levels than did subjects in the control group but there was no significant difference between the two forms of periodontitis. Within gingival tissue, L-plastin was confined to the inflammatory infiltrate. There was no statistically significant difference between serum and salivary L-plastin levels among the three study groups. CONCLUSION: The elevated gingival tissue expression and gingival crevicular fluid levels of L-plastin in both forms of periodontitis may denote the localized involvement of this novel molecule in the pathogenesis of the disease.

Elevated oral and systemic levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in periodontitis.

The Triggering Receptor Expressed on Myeloid cells 1 (TREM-1) is a cell-surface receptor of the immunoglobulin superfamily, involved in the propagation of the inflammatory response to bacterial challenge. Soluble (s)TREM-1 is released from the cell surface during the course of infection and is a useful inflammatory biomarker in the early diagnosis of systemic sepsis. The hypothesis of this study was that oral and systemic levels of sTREM-1 are elevated in periodontitis. Therefore, the aim was to investigate, by ELISA, the sTREM-1 concentrations in saliva and serum of individuals without periodontitis (control) and persons with chronic or generalized aggressive periodontitis. In saliva, sTREM-1 concentrations were higher in chronic and aggressive periodontitis than in the control group, by 3.3-fold and 5.6-fold, respectively. In serum, these differences were 1.7-fold and 2-fold, respectively. However, there were no significant differences between the two forms of periodontitis, neither in saliva nor in serum. Salivary and serum sTREM-1 levels positively correlated with full-mouth clinical periodontal parameters. In conclusion, the increased oral and systemic levels of sTREM-1 in periodontitis denote a value for this molecule as a biomarker for the disease and may also have implications in the association between periodontal infections and systemic inflammatory response.