Proteomic investigation of prognostic markers for treatment of aggressive periodontitis

Objectives: The outcome of periodontal treatment can vary greatly between different patients and sites. Modern proteomic technologies allow the investigation of possible molecular markers of prognosis without preconception of the nature of such molecules. As part of a larger study of prognostic factors for the treatment of aggressive periodontitis, the aim of this study was to investigate the presence of prognostic markers in gingival crevicular fluid (GCF) and saliva using Ciphergen's SELDI-based ProteinChip® protein array technology. Methods: 79 patients with generalized aggressive periodontitis were treated by a course of standardised non-surgical therapy. Saliva samples were collected using salivettes and GCF samples collected from 6 deep sites using sterile Periopaper. All samples were stored at -20°C until analysis. Initial clinical outcomes for all sites were measured at 3 months post-operatively. GCF and saliva samples were run in duplicate on CM10 and IMAC arrays and the data was analysed with PROTEINCHIP data analysis software. Results: The clinical outcomes of the patient cohort have been fully described previously (Hughes et al 2006, J Clin Perio, 33 , 663 - 70) . 54 patients were classified as “responders” and 25 as non responders according to clinical outcomes. The protein chip analysis was able to detect reproducibly a range of peaks in both GCF and Saliva. Univariate analysis of the data identified 2 prognostic markers of outcome in GCF, a 4189 Da peak present at significantly higher levels in the non-responders (p=0.036) and a 9035 Da peak present at significantly higher levels in the responders (p=0.022). Conclusions: This technology appears to be an appropriate platform for the analysis of both GCF and saliva. Further analysis should allow identification of the proteins associated with prognosis. The results may provide useful biomarkers for treatment outcome, and provide new insights into factors associated with treatment response.