The salivary and GCF AGE/sRAGE-IL-17 axis in periodontitis and diabetes: A pathophysiological perspective on disease progression and inflammation

Objective: Diabetes, if uncontrolled, increases the risk of periodontal disease and associated tooth loss. While AGE and sRAGE levels have been explored in diabetes, their role in localized inflammation in periodontium is poorly understood. The aim of this study was to investigate AGE/sRAGE ratio and IL-17 in saliva&gingival crevicular fluid in the presence of periodontitis in diabetic patients which may underlie disease development or progression. Design: This cross-sectional study included 64 patients, divided into 4 groups as healthy (H), periodontitis without diabetes(P), periodontitis patients with controlled diabetes(DP), periodontitis patients with poorly controlled diabetes(PDP). Periodontal clinical parameters were recorded. AGE, sRAGE, IL-17 levels in GCF and saliva samples were measured with ELISA and AGE/sRAGE ratio was determined. Results: GCF AGE/sRAGE ratio and IL-17 levels of periodontitis groups were significantly higher than H group, while sRAGE levels were significantly lower (p < 0.05). In addition, AGE/sRAGE ratio of PDP group were significantly higher than DP group in GCF and saliva (p < 0.05). ROC curve analysis showed significantly discriminative performance of the parameters in both GCF and saliva. HbA1c levels were positively correlated with AGE/sRAGE ratio in GCF and saliva(p < 0.05). Conclusions: This study demonstrated that GCF and salivary biomarkers, particularly IL-17 and AGE/sRAGE ratio, may have diagnostic potential in distinguishing periodontal disease severity in relation to glycemic status. ROC analysis supported the discriminative ability of these markers, especially in GCF, with satisfactory sensitivity and specificity. The AGE/sRAGE ratio in both GCF and saliva showed promise as a non-invasive biomarker, especially in patients with poorly controlled diabetes.