Salivary diagnostics in diabetes and periodontitis

Background + Aims

• MicroRNAs are small RNA molecules that regulate gene expression, influencing processes such as inflammation and antioxidant defence. Their presence in gingival crevicular fluid (GCF) may provide information about local periodontal disease and the influence of diabetes.
• This study aimed to:
  • Assess whether GCF levels of miR-146a and miR-155 were associated with periodontitis, type 2 diabetes and response to periodontal treatment, and to explore their relationship with antioxidant activity.

Materials + Methods

• The study included 96 adults, divided into four groups of 24 participants: periodontal health without diabetes, periodontal health with type 2 diabetes, periodontitis without diabetes, and periodontitis with type 2 diabetes.
• Participants with diabetes had been diagnosed for at least 2-years and had HbA1c below 8%. Smokers and people with other systemic diseases were excluded.
• Full-mouth examinations measured probing pocket depth, clinical attachment level, bleeding on probing, plaque and gingival inflammation.
• GCF was collected from 2 sites per participant. Quantitative real-time PCR measured microRNA expression, while laboratory testing assessed superoxide dismutase (SOD), an enzyme that helps neutralise reactive oxygen species.
• Participants with periodontitis received oral hygiene instruction, scaling and root planing, with reassessment 6-weeks after treatment.
• Statistical analyses examined associations after adjusting for age and sex. ROC curves assessed how well each marker distinguished periodontitis from periodontal health.

Results

• Both miR-146a and miR-155 were significantly elevated in participants with periodontitis, whether or not they had diabetes. Associations remained significant after adjustment for age and sex.
• Both markers decreased to levels comparable with the corresponding periodontally healthy groups, alongside improvements in clinical periodontal measurements.
• Higher levels of both microRNAs correlated with deeper periodontal pockets in participants with and without diabetes.
• Among periodontally healthy participants, miR-146a was higher in those with type 2 diabetes than in those without diabetes.
• In participants without diabetes, miR-146a achieved an AUC of 0.999, with 100% sensitivity and 96% specificity. In participants with diabetes, miR-155 performed best, with an AUC of 0.988, 92% sensitivity and 100% specificity.
  • Sensitivity indicates detection of affected participants
  • Specificity indicates correct identification of healthy participants.
• Antioxidant association – SOD activity was elevated in periodontitis, positively correlated with both microRNAs and decreased after treatment.

Limitations