Tissue-invasive Pathogens in Periodontitis Patients and Their Correlation with Pro-inflammatory Markers: An Analytical Case-control Study.

Aim: Tissue-invasive bacteria have been proposed to be a crucial factor in the etiopathogenesis of periodontitis, with the probable interaction of tissue-invasive bacteria with the innate immune response through inflammasomes, perpetuating periodontal attachment loss. This study aims to reveal the correlation between such tissue-invasive bacteria in upregulating inflammasomes and pro-inflammatory cytokines.

Materials and methods: This study recruited a total of 10 patients with stage III/IV and grade C periodontitis based on the bone loss to age ratio. Patient sites were grouped into group I: healthy sites with no clinical attachment loss (CAL); group II (mild-to-moderate): 1-4 mm of CAL; group III: severe (≥ 5 mm of CAL). Tissue samples were collected in these sites during periodontal flap surgery and assessed for both the bacterial genomic DNA and assessed for the upregulation of pro-inflammatory markers NOD-like receptor - Pyrin domain containing protein 3 (NLRP3), Human AIM2, Human Pro-TNFα, Human Pro-IL-1β, Human Pro-IL 6 and Human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) genes.

Results: The levels of NLRP3, AIM2, and pro-inflammatory cytokine levels were all higher in the severe sites when compared with the other two sites. The tissue invasive bacterial phylotypes in these sites were thereafter compared with the levels of the pro-inflammatory markers in the various groups. The fold changes in the pro-inflammatory markers evaluated in this study all hovered around 1, indicating not much difference in the upregulation of these markers of inflammation. Statistically, significant correlation between bacterial phenotypes in the healthy sites group and the pro-interleukin-6 (IL-6) cytokine expression was observed (r = 0.68; p < 0.04).

Conclusions: This study has highlighted the presence of tissue-invasive bacteria in sites with or without CAL. The fact that these healthy sites, after non-surgical therapy, have comparable levels of pro-inflammatory markers in the tissues may be explained by immune priming, by tissue- invasive periodontal pathogens.

Clinical significance: Tissue-invasive bacteria are present in periodontally healthy sites too, and non-surgical periodontal therapy is inadequate to eliminate them. Greater importance should be given to the soft tissue walls of the periodontal pocket in clinical management of periodontitis. How to cite this article: Victor DJ, Anandan NS, Appukuttan D, et al. Tissue-invasive Pathogens in Periodontitis Patients and Their Correlation with Pro-inflammatory Markers: An Analytical Case-control Study. J Contemp Dent Pract 2024;25(10):992-996.