Integrated Analysis of Oral Microbiome and Metabolome in T2DM Patients With Varying Glycemic Status

Objective: This study aimed to analyze the subgingival and salivary microbiome and metabolome in diabetic periodontitis patients with varying glycemic levels. Methods: Forty-two diabetic periodontitis patients were sampled of saliva, gingival crevicular fluid (GCF), and blood, and categorized into three groups based on systemic glycemic status. The microbiome was assessed using full-length 16S rRNA gene sequencing. Gas chromatography-mass spectrometry was performed for metabolome analysis. Results: The similarity in the structure and function of the flora in saliva and GCF was evident under good blood glucose control. Conversely, inadequate blood glucose control demonstrated a more distinct separation from saliva flora. Both salivary and GCF microorganisms exhibited greater periodontal pathogenicity, with salivary metabolites showing stronger associations with inflammation when Hemoglobin A1c (HbA1c) > 6.5%. Some periodontal pathogens, such as Veillonella atypica, showed significantly positive correlations with proinflammatory metabolites, including lactic acid and putrescine, etc. Salivary microbes demonstrated more sensitive responses than GCF to changes in blood glucose levels among type 2 diabetes mellitus (T2DM) patients. Conclusion: Under active blood glucose control, it indicates lower periodontal pathogenicity and inflammatory correlation in the oral microecology of T2DM patients. Saliva appears to offer superior diagnostic and monitoring value compared to GCF in the context of systemic disease surveillance.