Monitoring Salivary LPS Activity for Preventive, Participatory, Point-of-Care Periodontal Therapy
Objectives: Personalised, point-of-care dentistry is a move away from a ‘one size fits all’ approach to the prevention and care of patients with periodontal diseases, to one which uses new approaches to better manage patients’ gingival health and predisposition to the disease. Current diagnostic criteria for gingival diseases leave no opportunity to predict future tissue destruction or to formulate the appropriate treatment plan specific to each individual patient. Lipopolysaccharide (LPS) is the main virulence factor of periopathogenic bacteria and plays a key role in the development of periodontitis. The objectives of this study were to develop and evaluate a new salivary LPS-based, chair-side use biosensor for personalised, point-of-care, periodontal therapy.
Methods: Unstimulated whole saliva was collected from 30 healthy individuals and 31 patients with chronic periodontitis. LPS from saliva was extracted by Tri-reagent protocol. Endotoxin activity of extracted LPS was assessed using the recombinant factor C assay and its inflammatory potential was examined in THP-1 cells by measuring TNF-α and IL-8 production (ELISA). Chemical composition of LPS’s lipid-A domain was determined by MALDI-TOF analyses. Osteoclast differentiation potential of salivary LPSs was evaluated in mouse macrophages using TRAP staining.
Results: Endotoxin activity of salivary LPS extracted from patients with chronic periodontitis was significantly higher compared to healthy individuals. Production of TNF-α and IL-8 by THP-1 cells challenged by LPS extracts from chronic periodontitis patients was much higher compared to those treated with LPS extracts from healthy individuals. Lipid-A chemical composition analysis showed the predominance of bi-phosphorylated isoforms in chronic periodontitis samples. These samples exhibited significantly higher osteoclast differentiation potential compared to samples collected from patients with healthy gingivae.
Conclusions: Periodontal pathogens are able to trigger a detrimental hyper-inflammatory host immune response by producing high-potency LPS. Examination of salivary endotoxin activity could be a reliable, bacterially-derived biomarker for progression of periodontal diseases.