Assesment of gingival crevicular fluid and serum erbb4/neuregulin-4 levels in periodontal disease and health

This clinical trial aimed to evaluate gingival crevicular fluid (GCF) and serum Erb-b2 receptor tyrosine kinase 4 (ErbB4) and neuregulin (Nrg)-4 levels in periodontal health and disease. The association of these molecules between each other and with clinical parameters and also the alterations in these biochemical and clinical parameters after non-surgical periodontal therapy (NSPT) were determined. Systemically healthy and non-obese patients with gingivitis (G, n = 20), stage II grade B periodontitis (P1, n = 20), stage III grade B periodontitis (P2, n = 20) and periodontally healthy individuals (H, n = 20) were included in this parallel-design study. Clinical measurements and samples of gingival crevicular fluid (GCF) and serum were obtained at baseline and repeated at 1st month after NSPT. Enzyme-linked immunosorbent assay (ELISA) was used to determine levels of ErbB4, Nrg4, interleukin (IL)-6, IL-10, nitric oxide synthase (NOS)-2 and arginase (Arg)-1. The total amounts of GCF ErbB4 and Nrg4 were significantly higher in the G, P1 and P2 groups than the H group (p<0,01). The GCF total amount of IL-10 was significantly higher in H group than the other groups (p<0,01). However, there was no statistical difference between groups in terms of the GCF total amount of IL-6 (p>0,05). The GCF IL-6/IL-10 ratio were found to be significantly higher in the subjects with periodontal disease than those in periodontally healthy individuals (p<0,01). Serum ErbB4 levels were higher in P2 group than in H and P1 groups (p=0,05). On the other hand, there was no significant difference between groups in terms of serum concentrations of Nrg4. Serum NOS2 levels were significantly lower whereas serum Arg1 levels were higher in H group among the other groups (p<0,05). Additionally, the GCF total amount of ErbB4 and Nrg4 was found to have a positive and significant correlation with all clinical parameters and GCF IL-6/IL-10 ratio. The total amount of GCF ErbB4 and Nrg4 were significantly decreased (p<0,05), on the other hand serum concentrations of ErbB4 and Nrg4 did not change at 1st month after NSPT. Serum NOS2 concentrations and GCF IL-6/IL-10 ratios were decreased, while the total amounts of GCF IL-10 were increased after NSPT in both the G and P2 groups (p<0,05). In the shade of these aforementioned findings, ErbB4 and Nrg4 may have essential roles in resolution stage of gingival inflammation. Within the limits of this study, it can be concluded that ErbB4 and Nrg4 may be utilized as possible novel biomarkers for periodontal disease.