Salivary HMW adiponectin is a novel biomarker for periodontal disease

Objective: Total adiponectin concentrations are elevated in saliva and gingival crevicular fluid from patients with periodontal disease and decrease after treatment. In serum, adiponectin exists in three isoforms (high, middle and low molecular weight), with the high molecular weight isoform (HMW) having the most potent pro-inflammatory activity. Our knowledge of which isoforms are present in saliva and their role in periodontitis remains limited. We therefore investigated the salivary adiponectin isoform distribution and relationship of HMW adiponectin to periodontal disease status, periodontal inflamed surface area (PISA), and to salivary cytokine levels.  

Method: Unstimulated saliva samples were collected from 60 patients with chronic periodontitis pre- and 3 months post-treatment and also from 29 periodontally healthy individuals.  The presence of different adiponectin isoforms was determined in a native Western blot. Concentrations of salivary HMW adiponectin, IL-1β and IL-6 were measured using ELISA. 

Result: Presence of all adiponectin isoforms (high, middle and low molecular weight) was confirmed for the first time in saliva. ELISA analysis showed that HMW adiponectin concentrations were significantly higher in periodontitis (19.1±21.1 ng/ml) compared to health (8.1±7.8 ng/ml) (p<0.001). Post-treatment HMW adiponectin concentrations were significantly reduced in periodontitis patients (12.0±14.3 ng/ml) compared to pre-treatment values (p<0.01). HMW adiponectin concentrations were significantly and positively correlated with saliva IL-1β (ρ=0.346, p<0.01) and IL-6 (ρ=0.369, p<0.001), as well as with PISA (ρ=0.404, p<0.001). 

Conclusion: Salivary HMW adiponectin concentrations were significantly higher in periodontitis compared to periodontal health, and reduced after periodontitis treatment. Additionally, HMW adiponectin concentrations significantly correlated with salivary IL-6 and IL-1β concentrations and PISA. These findings could support a possible pro-inflammatory role for salivary HMW adiponectin in periodontal disease and its potential as a novel periodontitis biomarker. The work was supported by the IADR Young Investigator Research Award.