Salivary Levels of Interleukin-6 and Matrix-metalloproteinases-8 in Periodontitis and Diabetes

Objectives: The aim of this study was to evaluate the differences on the salivary levels of the interleukin-6 (IL-6) and matrix-metalloproteinase-8 (MMP-8) in patients with chronic periodontitis associated with type 2 diabetes.

Methods: Clinical and radiographic exams and HbA1c levels were used for groups categorization. A total of 80 subjects were divided in four groups: healthy control (C); periodontal disease (PD), periodontal disease and diabetes (PD+D) and diabetes only (D). Non-stimulated saliva samples (~3ml) from each patient (20 per group) were collected and analyzed by commercially available ELISA kits.

Results: Statistically significant differences were detected between groups for both biomarkers (ANOVA; MMP-8, p=0.001; IL-6, p=0.025). The average concentration of MMP-8 (ng/ml) for each group was PD=304.42±46.60; PD+D=404.92±75.90; D=395.88±75.22; C=39.29±15.20 and the average concentration of IL-6 (pg/ml) was PD=22.36±4.39; PD+D=31.06±9.07; D=10.01±1.91; C=9.21±2.79. Between groups comparisons showed that the MMP-8 concentration in the healthy control group was significantly lower than the diseased groups (post-hoc, p<0.01) and no differences between diseased groups were detected. For IL-6, statistically significant difference were observed between healthy control and PD+D and between diabetes and PD+D groups (post-hoc, p<0.05).

Conclusion: Saliva appears to be an adequate substrate for inflammatory biomarkers identification in periodontal and diabetics patients. Besides, it may be concluded that increased levels of MMP-8 and IL-6 in saliva may be related to the diseased condition. Taken together these data suggest that salivary levels of MMP-8 and IL-6 are potential candidate biomarkers for periodontal and systemic associated diseases diagnosis. More studies are necessary to validate the applicability of these biomarkers for routine clinical diagnosis. (CNPq. Grant #477428/2006-1 MTJ)