Proteomic Investigation For Gingival Crevicular Fluid Biomarkers In Periodontitis

Abstract

Gingival crevicular fluid (GCF) contains many proteins that could serve as useful diagnostic or prognostic biomarkers of Periodontal Disease. It is possible to detect and analyse the presence of and differential expression of the proteins in a fluid sample such as GCF, saliva or serum by ProteinChip® analysis using Surface Enhanced Laser Desorption/Ionization-Time of Flight-Mass Spectrometry (SELDI-TOF-MS) (Ciphergen Biosystems Inc, USA).

The aim of this study was to test the hypothesis that diagnostic GCF biomarkers could be identified to distinguish between patients with gingivitis, chronic periodontitis (CP) and aggressive periodontitis (AgP) using SELDI-TOF-MS.

Pre-treatment GCF samples were collected from 2 of the deepest sites from 24 patients (8 gingivitis, 8 CP & 8 AgP). Samples from each site were spotted onto ProteinChips®, evaluated by SELDI-TOF-MS and protein expression profiles were collected for each sample. Clustering and univariate analysis of both protein and peptide data was carried out using the Ciphergen Express® Software (Ciphergen Biosystems). The difference in expression levels across spectra was studied using the Expression Difference Mapping (EDM) tool in this software. Significance threshold was set at p < 0.05.

The EDM analysis revealed 76 peaks that were significantly different between gingivitis and periodontitis samples. 77.6 % of these had higher relative peak intensities in periodontitis than in gingivitis. Only 2 peaks were statistically significant when CP was compared with AgP. These values were higher in CP. Analysis of the EDMs among the periodontitis patients yielded 12 statistically significant biomarkers differentiating between smokers and non-smokers.

This study has demonstrated that profiling of GCF by SELDI-TOF-MS can distinguish between gingivitis and periodontitis and also specific proteins in GCF from periodontitis patients can be utilized as potential diagnostic biomarkers. Further studies are planned to identify these potential protein biomarkers