Gingival crevicular fluid can degrade Emdogain and inhibit Emdogain-induced proliferation of periodontal ligament fibroblasts

Background and Objective: Emdogain (R) (EMD), consisting mostly of amelogenin, is used in periodontal therapy to regenerate lost connective tissue. Emdogain is applied onto periodontally affected root surfaces, where it becomes exposed to proteolytic enzymes. In this study, we aimed to find out whether gingival crevicular fluid or matrix metalloproteinases (MMPs) could degrade EMD, and whether this degradation has consequences for in vitro cell proliferation. Material and Methods: We studied the effects of 156 gingival crevicular fluid samples collected from subjects with different stages of periodontal disease and from healthy control subjects and the effects of MMP-1, -2, -8, -9, -13 and -14 on the degradation of EMD using EMD-embedded zymography. The effects of gingival crevicular fluid with or without EMD and the effects of amelogenin on the proliferation of cultured periodontal ligament fibroblasts were studied by cell proliferation enzyme-linked immunosorbent assay kit. Results: Degradation of Emdogain induced by gingival crevicular fluid was greater in samples from all stages of periodontal diseases compared with healthy control samples. Of the MMPs studied, only MMP-2 and MMP-8 showed limited EMD-degrading activities. One hundred micrograms per millilitre of EMD increased proliferation of periodontal ligament fibroblasts on average by 24% (confidence interval 0.60-0.64) and at 200 mu g/mL by 30% (confidence interval 0.62-0.68) compared with control fibroblasts (confidence interval 0.48-0.52). However, gingival crevicular fluid (10 mu g/mL) together with 100 mu g/mL EMD induced the proliferation only by 6% (confidence interval 0.51-0.55) and with 200 mu g/mL EMD by 12% (confidence interval 0.54-0.58). Amelogenin at 200 mu g/mL decreased the proliferation of periodontal ligament fibroblasts by 54% (confidence interval 0.22-0.25). Conclusion: We suggest that diseased gingival crevicular fluid containing various proteases leads to degradation of EMD and decreased proliferation of periodontal ligament fibroblasts.