Diagnostic biomarkers related to periodontal disease activity in diabetics

The overall aim of this study was to monitor the periodontal disease activity and suggest potential salivary biomarkers related to this activity in chronic periodontitis patients with or without type 2 Diabetes mellitus (DM), based on the evaluation of gene expression profile of progressive periodontal sites and salivary inflammatory proteins. Fifty-six patients were enrolled, 21 with chronic periodontitis (PD group), 20 with chronic periodontitis and DM (PD+DM group) and 15 periodontal- and systemically healthy (control). Radiographs were taken before and two months after non-surgical periodontal therapy, and radiographic subtraction was performed from pairs of these radiographs. Measurements of the areas with density loss were recorded. Unstimulated saliva collection, glycated hemoglobin (HbA1c) measurement and periodontal examination probing pocket depth (PPD), relative clinical attachment level (rCAL), bleeding on probing (BOP) and plaque index (PI) were also conducted before and two months after non-surgical periodontal therapy. The periodontal sites with progressive attachment loss 1 mm at the recall visit were considered active sites according to the adapted method of tolerance. Gingival biopsies of active and non-active sites with similar clinical parameters were harvested for gene expression analysis of the immune-inflammatory response with Real Time PCR Array. Saliva samples were analyzed by Multiplex Cytokine Profiling Immunoassay for analysis of protein expression profile. In PD group, 9% of the sites were classified as active and in PD+DM group, 12% (p > 0.05). The clinical attachment loss mean was higher in the PD+DM group (1.34±0.23 mm) compared to the PD group (1.21±0.16 mm) (p < 0.05). There was a correlation between clinical attachment loss and darkened radiographic areas in active sites of the PD group (R = 0.79, p = 0.001) and PD+DM group (R = 0.86, p < 0.001). Both PD and PD+DM groups showed a down-regulated profile compared to healthy subjects (control group). When compared PD group to PD+DM, patients with diabetes had an upregulated profile. Active sites of the PD group showed nine genes (ABCF1, CD40LG, IL10, IL5, CCR2, CCR4, CCR7, CCL18 and CXCL1) differentially expressed (p < 0.05) with an up-regulated profile. Active sites of the PD+DM group showed six genes (LTA, CXCR1, CCL19, CCL8, CCL17 and CXCL12) differentially expressed (p < 0.05) with an up-regulated profile. After non-surgical periodontal therapy, there was a significant reduction of clinical parameters and HbA1c levels (p < 0.05), accompanied by a reduction of some salivary proteins (IL1b, IL1ra, IL10, IL17, TGFb, IL8, eotaxin and MCP-3) in groups PD and PD+DM, but without statistically significant difference (p > 0.05). In conclusion, this study was able to monitor the periodontal disease activity in periodontal patients with or without diabetes after the non-surgical periodontal therapy; it was possible to identify genes differentially expressed in active sites from both groups, which may be considered useful in indicating potential biomarkers for the diagnosis of active periodontal disease; salivary proteins show a trend in distinguishing the standard of health and disease and may be used in the future as potential biomarkers of periodontitis with or without diabetes. (AU)