Investigation of NLRP3, Caspase-1, and Gasdermin-D levels in the gingival crevicular fluid of individuals with periodontitis

Aim: Pyroptosis is a form of programmed cell death distinct from apoptosis, associated with the inflammatory response. The canonical pyroptotic pathway is typically triggered by intracellular pathogenic infections and is linked to both the innate and adaptive immune systems of the host. The aim of this study is to investigate the levels of the key components of the canonical pyroptotic pathway—NLRP3, caspase-1, gasdermin D (GSDM-D), interleukin- 1 beta (IL-1β), and IL-18—in the gingival crevicular fluid (GCF) of individuals with periodontitis, a chronic inflammatory disease caused by periodontal pathogens. Materials and Methods: The study included a total of 72 individuals, divided into three groups: stage 3 grade C periodontitis (n=24), gingivitis (n=24), and periodontal health (n=24). To determine periodontal status, full-mouth probing depth (PD), clinical attachment loss (CAL), bleeding on probing (BOP +/-), gingival index (GI), and plaque index (PI) values were recorded. GCF levels of NLRP3, caspase-1, GSDM-D, IL-1β, and IL-18 were measured using ELISA and presented as total amounts. Data were analyzed using non-parametric statistical tests. Results: The GCF levels of NLRP3, caspase-1, and GSDM-D in the periodontally healthy group were found to be significantly higher than those in the gingivitis and periodontitis groups (p<0.05). The GCF levels of NLRP3, caspase-1, and GSDM-D were similar between the gingivitis and periodontitis groups (p>0.05). The GCF IL-1β level in the periodontitis group was significantly higher than in both the gingivitis and periodontally healthy groups (p<0.05). Conversely, the GCF IL-18 level in the periodontitis group was significantly lower than in the periodontally healthy group (p<0.05). GCF levels of NLRP3, caspase-1, GSDM- D, and IL-18 were positively correlated with each other (p<0.05). Conclusion: There are a limited number of studies in the literature regarding the role of the canonical pyroptotic pathway in the pathogenesis of periodontal disease. To the best of our knowledge, this is the first study to report GCF GSDM-D levels in both periodontally healthy and diseased individuals. Within the limitations of this study, the lower GCF levels of NLRP3, caspase-1, GSDM-D, and IL-18 observed in individuals with periodontitis suggest that these molecules may play a role in the pathogenesis of periodontal disease. Large-scale cohort studies are needed to further elucidate the potential relationship between pyroptosis and periodontal disease. Keywords: Periodontal disease, gingival crevicular fluid, cell death, pyroptosis