Subgingival Endotoxin Activity in Patients With Chronic Periodontitis

Objectives: Regulation of lipopolysaccharide (LPS) chemical composition is an important naturally occurring mechanism that contributes to the resolution of bacteria - host immune system interactions into either a symbiotic or pathogenic relationship. Members of subgingival microbiota have evolved adaptive mechanisms to environmental changes and can synthesize different isoforms of LPS. LPS modifications can alter the bacterium’s outer membrane integrity, susceptibility to antimicrobial peptides, immune stimulation and disease pathogenesis. The objectives of this study were to compare endotoxin activity and inflammatory potential of LPS extracted from subgingival plaque samples collected from patients with chronic periodontitis and healthy individuals.
Methods: Subgingival plaque samples were collected by paper points from 31 patients with chronic periodontitis and 30 healthy individuals. LPS was extracted by Tri-reagent protocol. Endotoxin activity of extracted LPS was assessed using the recombinant factor C assay and their inflammatory potential was examined in THP-1 derived M1 and M2 macrophages by measuring TNF-α and IL-8 production (ELISA).
Results: Endotoxin activity of LPS extracted from patients with chronic periodontitis was significantly higher compared to healthy individuals. There was no correlation between plaque index and LPS endotoxin activity. Production of TNF-α and IL-8 by M1 and M2 macrophages challenged by LPS extracts from chronic periodontitis patients was much higher compared to those treated with LPS extracts from healthy individuals.
Conclusions: Periodontal pathogens are able to trigger a detrimental hyper-inflammatory host immune response by producing high-potency LPS. Subgingival endotoxin activity could be a potential, bacterially-derived biomarker for progression of periodontal diseases.