LIGHT protein: A novel gingival crevicular fluid biomarker associated with increased probing depth after periodontal surgery

Aim: To evaluate the protein profiles in gingival crevicular fluid (GCF) in relation to clinical outcomes after periodontal surgery and examine if any selected proteins affect the mRNA expression of pro-inflammatory cytokines in human gingival fibroblasts. Materials and Methods: This exploratory study included 21 consecutive patients with periodontitis. GCF was collected, and the protein pattern (n = 92) and clinical parameters were evaluated prior to surgery and 3, 6 and 12 months after surgery. Fibroblastic gene expression was analysed by real-time quantitative polymerase chain reaction. Results: Surgical treatment reduced periodontal pocket depth (PPD) and changed the GCF protein pattern. Twelve months after surgery, 17% of the pockets showed an increase in PPD. Levels of a number of proteins in the GCF decreased after surgical treatment but increased with early signs of tissue destruction, with LIGHT being one of the proteins that showed the strongest association. Furthermore, LIGHT up-regulated the mRNA expression of pro-inflammatory cytokines interleukin (IL)-6, IL-8 and MMP9 in human gingival fibroblasts. Conclusions: LIGHT can potentially detect subjects at high risk of periodontitis recurrence after surgical treatment. Moreover, LIGHT induces the expression of inflammatory cytokines and tissue-degrading enzymes in gingival fibroblasts.