Distinct salivary-biomarkers profile in health versus chronic-periodontitis and treatment effects

Background: Saliva has potential to diagnose chronic periodontitis (CP). Changes in tissue-expression of pattern-recognition-receptors (PRRs), which recognize periodontal-pathogens, correlate with CP.  It follows that PRRs-expression in nucleated-cells shed in saliva (NCs) and soluble-PRRs may differentiate CP from health. Additionally, cytokines in GCF correlate with worsening CP, which may-be reflected in saliva. One significant test for biomarkers is changes in response to treatment.

Objectives: Comparison of CP salivary-biomarkers profile with health and to study treatment effects.

Methods: Unstimulated-whole-saliva (UWS) collection/recording of routine clinical/periodontal-parameters were done for two groups {CP-group (≥30% sites with ≥4mm clinical loss of attachment (CAL)) versus healthy H-group (minimal CAL & clinical-inflammation)} of systemically-healthy individuals (16-per-group), at defined time points.  NCs & clarified saliva (CS) were separated from UWS. mRNA was extracted from NCs and TLR-2 expression was quantitated through real-time-PCR (Table-1). CS  depleted of Immunoglobulin & amylase (prevent large molecule interferences) and diluted to 1µg/ml of salivary-protein in PBS (normalize for variations in liquid volume) was used to quantify biomarkers through ELISA. Significance between H and CP-group biomarkers was determined through Mann-whitney-‘U'-Test. one-tailed-paired-‘T'-tests determined significance of SRP-mediated salivary-biomarker changes in CP.

Results: Table-2 compares clinical-profiles of H and CP-groups and changes after SRP within CP-group. Table-3 compares changes in salivary-biomarkers.  Briefly salivary sTLR-2, IL-17, & IL-10, were significantly higher, and sCD14, IL-6 , IL-4  &TLR-2 mRNA were significantly lower in H (compared to CP). In CP, salivary sTLR-2 & IL10 increased significantly at 1 & 6 weeks after SRP whilst IL-4 decreased significantly at 6 weeks.

Conclusions: Salivary-biomarkers profile is distinct between health and CP. sTLR-2, IL-10 and IL-4 may serve as short-term biomarkers for monitoring response to SRP.  sCD14, TLR2-mRNA and other cytokines need exploration as long-term-response biomarkers. Depletion of amylase & immunoglobulin and normalization for liquid-volume may be important steps in biomarkers quantification.