Hyperglycemia Dysregulates Host Responses to Dual Species Endodontic Biofilm-Derived Products: An In Vitro Study.

This study investigated the effects of hyperglycemia on mitochondrial metabolic activity and inflammatory responses in periodontal ligament fibroblasts (PdLFs) and THP-1-derived macrophages exposed to endodontic biofilm supernatants. PdLFs and macrophages were TGF-β1-cultured in a Transwell system and exposed for 48 h to normoglycemic or hyperglycemic conditions (HG + AGEs), with or without supernatants from 7-day mono- or dual-species biofilms of Enterococcus faecalis (E. faecalis) and Fusobacterium nucleatum (F. nucleatum). Biofilm biomass, colony-forming units, mitochondrial metabolic activity, and cytokine production were assessed. E. faecalis showed higher bacterial counts, whereas F. nucleatum produced greater biomass. Hyperglycemia intensified the inhibitory effect of E. faecalis and the stimulatory effect of F. nucleatum on mitochondrial activity. The dual-species supernatant induced an intermediate metabolic response but the most dysregulated inflammatory profile under hyperglycemia, with increased TNF-α and reduced TGF-β1. Hyperglycemia reprograms host responses to biofilm-derived products, while polymicrobial interactions amplify inflammatory dysregulation.