Salivary Gene Expression of RANK, RANKL, and OPG in Type 1 Diabetes Mellitus and Periodontal Disease Patients

OBJECTIVES: The relationship between type 1 diabetes mellitus (T1DM) and periodontal disease may exhibit by the alteration of bone metabolism. However, evidence for this relationship is scarce and inconclusive. Thus, the aims of the present study were to investigate salivary receptor activator of nuclear factor kappa-β (RANK), receptor activator of nuclear factor kappa-β ligand (RANKL), osteoprotegerin (OPG) gene expression and the RANKL:OPG ratio in T1DM and non-T1DM. Secondary objective was to determine the relationships of RANK, RANKL and OPG gene expression to clinical parameters of T1DM and periodontal disease. MATERIALS AND METHODS: Twenty patients with T1DM and twenty age-matched non-T1DM were recruited. Clinical periodontal parameters were measured. Total RNA was isolated from non-stimulated saliva, and the relative gene expressions of RANK, RANKL, OPG and RANKL:OPG ratio were determined by quantitative real-time polymerase chain reaction. RESULTS: The T1DM group had significantly higher mean periodontal parameters than the non-T1DM group, while the mean plaque scores of both groups were not significantly different. There was a trend of higher relative gene expression of RANK, RANKL, and the RANKL:OPG ratio and lower expression of OPG in T1DM group but no statistic significant different when compared to non-T1DM. In the T1DM group, RANKL:OPG correlated with the percentage of bleeding sites, whereas RANK, RANKL, and HbA1c levels correlated with pocket depth. CONCLUSIONS: Bone metabolisms demonstrating by decreased OPG gene expression and upregulated of RANK, RANKL, RANKL:OPG with higher pocket depth and bleeding in T1DM may play an important role in periodontal destruction in T1DM.