Development and Evaluation of a Novel, Lipid-A Based Biosensor for Personalised and Predictive Periodontal Therapy
Objectives: Lipopolysaccharide (LPS) is the main virulence factor of periopathogenic bacteria and plays a key role in the development of periodontitis. 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 develop and evaluate a new LPS-based, chair-side use biosensor for personalised, point-of-care, periodontal therapy.
Methods: Subgingival plaque samples were collected by paper points from 30 healthy individuals and 31 patients with chronic periodontitis before and after non-surgical periodontal therapy. 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). Chemical composition of LPS’s lipid-A domain was determined by MALDI-TOF analyses.
Results: Endotoxin activity of LPS extracted from patients with chronic periodontitis was significantly higher compared to healthy individuals and post-treatment samaples. 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 and treated periodontitis patients. Lipid-A analysis showed the predominance of bi-phosphorylated isoforms in chronic periodontitis samples.
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 reliable, bacterially-derived biomarker for progression of periodontal diseases.