Soluble Forms of the Receptor for Advanced Glycation Endproducts (RAGE) in Periodontitis

The receptor for advanced glycation endproducts (RAGE) is critically involved in the pathobiology of chronic inflammatory diseases. Soluble forms of RAGE have been proposed as biomarkers of severity in inflammatory and metabolic conditions, and in monitoring therapeutic responses. The aim of the present study was to determine circulating levels of the soluble forms of RAGE in periodontitis and to evaluate the expression of cell-bound, full-length RAGE and its antagonist AGER1 locally, in gingival tissues. Periodontitis patients and periodontally healthy, sex- and age-matched controls (50 per group) were included. Serum levels of total soluble RAGE and cleaved RAGE (cRAGE) were significantly lower in periodontitis patients. Levels of the endogenous secretory esRAGE were similar in the two groups. cRAGE remained significantly lower in the periodontitis group following multiple adjustments, and had a statistically significant inverse correlation with body mass index and all periodontal parameters. In periodontitis patients, gene expression of full-length RAGE and of AGER1 were significantly higher in periodontitis-affected gingival tissues compared to healthy gingiva. Soluble forms of RAGE, particularly cRAGE, may serve as biomarkers for the presence and severity/extent of periodontitis, and may be implicated in its pathogenesis and its role as a systemic inflammatory stressor.