Oral pathobiont induces systemic inflammation and metabolic changes associated with alteration of gut microbiota.

Periodontitis has been implicated as a risk factor for metabolic disorders such as type 2 diabetes, atherosclerotic vascular diseases, and non-alcoholic fatty liver disease. Although bacteremias from dental plaque and/or elevated circulating inflammatory cytokines emanating from the inflamed gingiva are suspected mechanisms linking periodontitis and these diseases, direct evidence is lacking. We hypothesize that disturbances of the gut microbiota by swallowed bacteria induce a metabolic endotoxemia leading metabolic disorders. To investigate this hypothesis, changes in the gut microbiota, insulin and glucose intolerance, and levels of tissue inflammation were analysed in mice after oral administration of Porphyromonas gingivalis, a representative periodontopathogens. Pyrosequencing revealed that the population belonging to Bacteroidales was significantly elevated in P. gingivalis-administered mice which coincided with increases in insulin resistance and systemic inflammation. In P. gingivalis-administered mice blood endotoxin levels tended to be higher, whereas gene expression of tight junction proteins in the ileum was significantly decreased. These results provide a new paradigm for the interrelationship between periodontitis and systemic diseases

Engineering of bioactive nanocomplexes on dental floss for targeted gingival therapy

Abstract Periodontitis induced by chronic subgingival infection is a ubiquitous disease that causes systemic inflammatory consequences and poses a negative impact on quality of life. The disease is treated and potentially prevented by patient's self‐care aimed at eliminating the oral pathogens from the region. Currently available products for interdental self‐care, including dental floss and interdental brush, have limited ability to prevent the disease. Here, we report a coated dental floss thread, termed “nanofloss,” which uses polyphenol‐based nanocoating to functionalize the floss thread with therapeutic agents. Multiple therapeutics can be integrated into the nanofloss including antibacterial small molecules and proteins. Flossing with nanofloss‐delivered therapeutic agents to the challenging subgingival region with long‐term retention even against the flushing action of the oral fluid in vivo. Our in vitro and in vivo studies demonstrate that chlorhexidine gluconate‐loaded nanofloss effectively treats the subgingival infection by Porphyromonas gingivalis. Collectively, the nanofloss offers a promising and easily usable tool for targeted self‐care of subgingival infection against periodontitis

Oral Administration of P. gingivalis Induces Dysbiosis of Gut Microbiota and Impaired Barrier Function Leading to Dissemination of Enterobacteria to the Liver.

Although periodontitis has been implicated as a risk factor for various systemic diseases, the precise mechanisms by which periodontitis induces systemic disease remain to be elucidated. We have previously revealed that repeated oral administration of Porphyromonas gingivalis elicits endotoxemia via changes in the gut microbiota of the ileum, and thereby induces systemic inflammation and insulin resistance. However, it is not clear to what extent a single administration of P. gingivalis could affect gut microbiota composition, gut barrier function, and subsequent influx of gut microbiota into the liver. Therefore, in the present study, C57BL/6 mice were orally administered P. gingivalis (strain W83) once and compared to sham-inoculated mice. The phylogenetic structure and diversity of microbial communities in the gut and liver were analyzed by pyrosequencing the 16S ribosomal RNA genes. Serum endotoxin activity was determined by a Limulus amebocyte lysate test. Gene expression in the intestine and expression of 16S rRNA genes in the blood and liver were examined by quantitative polymerase chain reaction. Administration of P. gingivalis significantly altered gut microbiota, with an increased proportion of phylum Bacteroidetes, a decreased proportion of phylum Firmicutes, and increased serum endotoxin levels. In the intestinal tissues, gene expression of tjp-1 and occludin, which are involved in intestinal permeability, were downregulated. Higher amounts of bacterial DNA were detected in the liver of infected mice. Importantly, changes in gut microbiota preceded systemic inflammatory changes. These results further support the idea that disturbance of the gut microbiota composition by orally derived periodontopathic bacteria may be a causal mechanism linking periodontitis and systemic disease

Sequencing analysis of the gut microbiota obtained from <i>P</i>. <i>gingivalis</i>-administered and sham-administered mice.

<p>(A) Diversity of bacterial species as indicated by Chao1 rarefaction measure. (B) PCoA of fecal microbiota from <i>P</i>. <i>gingivalis</i>-administered and sham-administered mice. (Unweighted distance: R = 0.2646, <i>p</i> < 0.01; Weighted distance: R = -0.0251, <i>p</i> = 0.018, ANOSIM test).</p

Effect of oral administration of <i>P</i>. <i>gingivalis</i> on gut barrier function and endotoxemia.

<p>(A) Quantitative PCR analysis of tight junction genes in the small intestine of <i>P</i>. <i>gingivalis</i>-administered mice and sham-administered mice at 24 hrs and 48 hrs after <i>P</i>. <i>gingivalis</i> administration. The relative mRNA expressions of the genes of interest were normalized to the relative quantity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA (N = 7 in each group). (B) Relative abundance of bacteria in the liver and blood of <i>P</i>. <i>gingivalis</i>-administered mice and sham-administered mice (N = 7 in each group). (C) Serum endotoxin (LPS) concentration (EU/mL) were determined after <i>P</i>. <i>gingivalis</i> administration or sham administration (N = 7 in each group). (*<i>p</i> < 0.05, **<i>p</i> < 0.01, Mann-Whitney U-test).</p

Comparison of the gut microbiota between <i>P</i>. <i>gingivalis</i>-administered and sham-administered mice by 16S rRNA sequencing analysis (N = 6 in the experimental group, N = 7 in the control group).

<p>(A) Relative abundances of each bacterial group at the phylum level at 24 hrs and 48 hrs after <i>P</i>. <i>gingivalis</i> administration are indicated by box plots. (*<i>p</i> < 0.05, **<i>p</i> < 0.01, Mann-Whitney U-test). (B) Relative abundance of each bacterial group at the genus level were significantly increased or decreased are shown. Each assigned taxonomy obtained from 16S rRNA deep sequencing was compared to Silva database using UCLUST. (*<i>p</i> < 0.05, **<i>p</i> < 0.01, Mann-Whitney U-test).</p

β2-Microglobulin and Neutrophil Gelatinase-Associated Lipocalin, Potential Novel Urine Biomarkers in Periodontitis: A Cross-Sectional Study in Japanese

Objectives. Several serum biomarkers have been reported to increase in periodontitis patients as possible mediators linking periodontal inflammation to systemic diseases. However, the relationship between periodontitis and urine biomarkers is still unclear. The aim of this cross-sectional study was to investigate potential urine biomarkers of periodontitis in a Japanese population. Materials and Methods. This study included 108 male subjects, and microbiological and clinical parameters were evaluated as a periodontitis marker. The correlation between nine urine biomarkers (typically used to diagnose kidney disease) and periodontal parameters was analyzed. Based on the findings, β2-microglobulin (β2-MG) and neutrophil gelatinase-associated lipocalin (NGAL) were selected for comparison and multivariate regression analysis, and the Kruskal–Wallis test followed by Bonferroni correction was used to identify differences in their concentrations between the three periodontitis groups (severe, moderate, and no/mild periodontitis). Results. β2-MG and NGAL exhibited a significant correlation with clinical parameters of periodontitis. The prevalence of clinical parameters such as bleeding on probing and number of sites with probing depth (PD) ≥ 6 mm were greater in the β2-MG high group (≥300 μg/g creatinine) than in the normal group (P=0.017 and 0.019, respectively). Multivariate regression analysis indicated that the number of sites with PD ≥ 6 mm was independently associated with urine β2-MG. Moreover, the number of sites with the clinical attachment level (CAL) ≥ 6 mm was greater in the NGAL high group (highest quartile) (P=0.041). Multivariate regression analysis showed that the number of sites with CAL ≥ 6 mm was associated independently with urine NGAL. Finally, β2-MG was significantly higher in the severe periodontitis subjects compared to the no/mild periodontitis subjects. Conclusion. The significant association between urine β2-MG or NGAL and periodontitis was revealed. These biomarkers can potentially be used to screen for or diagnose periodontitis. This trial is registered with the UMIN Clinical Trials Registry UMIN000013485