Obesity Is Associated with a Weakened Gingival Inflammatory Cytokine Response.

Background and Objectives: An obesity-related elevated body mass index (BMI) across life is associated with chronic low-grade inflammation and increased levels of C-reactive protein (CRP) in blood. CRP is a marker and promoter of inflammation. The objectives of this study were to examine the effect of obesity on the relationship between peripheral and gingival CRP levels and to examine the effects of gingival CRP levels on gingival fluid inflammatory cytokines in periodontitis-resistant obese individuals. Materials and Methods: Thirty-nine participants in good periodontal health were recruited. Twenty patients were classified as lean and nineteen as obese based on their BMI levels. A thorough periodontal assessment was carried out. Gingival crevicular fluid (GCF) and blood samples were collected. Both GCF and blood samples were analyzed for interleukin-1ß (IL-1ß), interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10), interleukin-17A (IL-17A), and CRP. Results: GCF CRP levels were significantly higher in the obese than in the lean individuals. No statistically significant differences were noted between the two groups in either GCF or blood in terms of any of the inflammatory cytokine levels. IL-17A was not detected in the GCF of most subjects in both groups. GCF CRP levels were positively associated with blood CRP levels, and the association tended to be stronger in the obese individuals. GCF CRP showed no associations with GCF IL-10 in both groups. Although GCF CRP levels were positively associated with multiple GCF inflammatory cytokines (e.g., IL-1ß, IL-6, IL-8, and TNF-α) in all subjects, the associations tended to be weaker in the obese individuals (e.g., IL-1ß, IL-6, and TNF-α). Furthermore, the levels of the GCF inflammatory cytokines IL-6 and TNF-α were decreased in the obese individuals. Conclusions: Obesity unfavorably influences the relationship between blood and GCF CRP levels and promotes increased CRP levels in GCF. Collectively, the findings suggest a weakened inflammatory cytokine response in the gingival tissues of obese individuals.

Metabolomic profiles of obesity and subgingival microbiome in periodontally healthy individuals: A cross-sectional study.

AIM: Since blood metabolomic profiles of obese individuals are known to be altered, our objective was to examine the association between obesity-related metabolic patterns and subgingival microbial compositions in obese and non-obese periodontally healthy individuals. MATERIALS AND METHODS: Thirty-nine periodontally healthy subjects were enrolled. Based on body mass index scores, 20 subjects were categorized as lean and 19 as obese. A comprehensive periodontal examination was performed. Subgingival plaque and blood samples were collected. Plaque samples were analysed for bacteria using 16S rDNA sequencing. Untargeted metabolomic profiling (mass spectrometry) was used to quantify metabolites in serum. RESULTS: Obese subjects were statistically associated with several periodontopathic taxa including Dialister invisus, Prevotella intermedia, Prevotella denticola, Fusobacterium nucleatum_subsp.vincentii, Mogibacterium diversum, Parvimonas micra and Shuttleworthia satelles. In obese individuals, an amino acid-related metabolic pattern was elevated; however, there was a decrease in metabolic patterns related to lipids and cofactor/vitamins. These metabolic perturbations were associated with multiple subgingival bacterial species that differentiated lean from obese individuals. CONCLUSIONS: Obesity-related perturbations in circulating blood metabolites are associated with the development of periodontopathic bacterial colonization in the subgingival microbiome and consequently may increase the risk for periodontal disease in obese individuals.

Cross-sectional comparisons of subgingival microbiome and gingival fluid inflammatory cytokines in periodontally healthy vegetarians versus non-vegetarians.

BACKGROUND: Vegetarian diets are known to reduce inflammation. The objective of this study was to test the hypothesis that reduced inflammation associated with a vegetarian diet would promote a more commensal subgingival bacterial profile. METHODS: A total of 39 periodontally healthy subjects (PD ≤3 mm, bleeding on probing <10%) were enrolled. Dietary intake was assessed by a food frequency questionnaire. A comprehensive periodontal examination was performed. Gingival crevicular fluid (GCF) and subgingival plaque samples were collected. GCF samples were assessed for interleukin-1ß, interleukin-6, interleukin-8, tumor necrosis factor-alpha, and interleukin-10. Plaque samples were analyzed for bacteria using 16S rDNA sequencing on an Illumina platform. GenBank database was used for taxonomy classification. RESULTS: Twenty-three subjects were categorized as vegetarian and 16 non-vegetarians. Clinical periodontal measures and GCF cytokine levels were statistically comparable between the two groups. Measures of microbial richness and alpha diversity were also comparable between the two dietary groups. Vegetarians harbored higher levels of phyla associated with gingival health (Actinobacteria, and Proteobacteria). Two species known to be associated with periodontitis (Mogibacterium timidum and Veillonella rogosae) were prominent in non-vegetarians. Pearson's correlations between GCF inflammatory cytokines and microbial taxa differed between vegetarians and non-vegetarians. In vegetarians, the anti-inflammatory cytokine IL-10 positively correlated with two species known to be associated with periodontal health (Peptidiphaga sp. HMT183 and Rothia aeria). CONCLUSIONS: Diet is directly and indirectly associated with the microbial composition of subgingival plaque. A vegetarian diet may promote a subgingival microbiota associated with periodontal health.