Accumulating evidence indicates that epithelia are not merely mechanical barriers but also important elements of the innate immune system. The present study was performed to examine cytokine responses of oral epithelial cells after infection with the periodontal pathogen Porphyromonas gingivalis. The KB-cell line and primary cultures of periodontal pocket epithelium were infected with P. gingivalis for assessment of bacterial invasion by an antibiotic protection assay, and examination of expression of interleukin-1 beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha by in situ hybridization and immunohistochemistry. We observed that P. gingivalis induces a strong cytokine response, positively correlated with the adhesive/invasive potential of the infecting strain, in both KB cells and primary cultures. These findings indicate that the epithelial cells of the periodontal pocket are an integral part of the immune system, eliciting cytokine responses to a bacterial challenge. In this context, the adhesive/invasive phenotype of P. gingivalis appears to contribute to pathogenicity.
Objective: We used epidemiologic data of clinical periodontal status from two population-based samples in two countries, United States and Germany, to examine 1) the impact of age on the relative contribution of recession and pocketing on the distribution of clinical attachment loss, and 2) whether it is feasible to define age-dependent thresholds for severe periodontitis. 2012. NHANES used a full-mouth examination protocol to collect data on recession (R), pocket depth (PD) and clinical attachment loss (CAL) for six sites/tooth on a maximum of 28 teeth; SHIP-Trend used a half-mouth examination at four sites/tooth. In both samples, percentile distributions of mean CAL/person were generated for each 5-year age interval. Age-dependent thresholds defining the upper quintile of mean CAL were calculated for both samples. The topographic intraoral distribution of CAL and the relative contribution of R and PD on CAL was assessed.Results: Mean CAL increased linearly with age in both samples and was higher in SHIP-Trend than NHANES across the age spectrum. In contrast, mean PD was constant across age groups in both populations. R contributed increasingly to CAL with age, especially after 45 to 49 years. Upper quintile mean CAL thresholds in NHANES were < 3 mm for ages up to 39 years, and under 3.58 mm in all other age groups. Corresponding values in SHIP-Trend were also < 3 mm in ages up to 39 years but increased linearly with age up to 7.21 mm for ages ≥75 years.Conclusions: Despite substantial differences in the overall severity of attachment loss between the two samples, common patterns of CAL and of the relative contribution of R and PD to CAL with increasing age were identified. Although periodontitis severity may vary in different populations, empirical evidence-driven definitions
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