The role of microbiome in the pathogenesis of oral-gut-liver axis between periodontitis and nonalcoholic fatty liver disease

Association between virus infection and periodontitis: Evidence from the National Health and Nutrition Examination Survey 2009-2014

Periodontitis is a cumulative inflammatory disease associated with multiple health conditions and various systemic diseases. As a common disease, virus infection along with its consequences has become a serious health burden. The study aims to evaluate the relationship between common viruses including hepatitis virus, human immunodeficiency virus (HIV), herpes simplex virus (HSV), human papillomavirus (HPV), and periodontitis. The data from the US National Health and Nutrition Examination Survey (NHANES) 2009-2014 was adopted and screened through, including 10 714 participants. Generalized linear regression was conducted to verify the relationships between the virus infections and periodontitis. Moreover, we also performed analyses in age and gender subgroups. The results suggested that the infection of HCV, HSV-1, and HSV-2 was significantly associated with the prevalence of periodontitis (odds ratio [OR] 1.46, 95% confidence interval [CI] 1.26-1.70; OR 1.09, 95% CI 1.05-1.13; OR 1.06, 95% CI 1.01 - 1.11, respectively) and risk of developing moderate or severe periodontitis (OR 1.51, 95% CI 1.29-1.77; OR 1.08, 95% CI 1.04-1.12; OR 1.05, 95% CI 1.01-1.10, respectively) after adjusting all relevant co-factors. Subgroup analyses revealed a steady association between periodontitis and hepatitis C virus (HCV) or HSV-1 infection, while the relationship between HSV-2 and HPV infection can also be found in some subgroups. The presence of HCV and HSV infection was found to be significantly associated with the prevalence of periodontitis, including moderate or severe cases. Moreover, the association of periodontitis and HPV infection can also be observed in people < 35 years.

Oral and Intestinal Bacterial Flora in Patients with Increased Periodontal Inflamed Surface Area: A Cross-Sectional Study

Background/Objectives: Periodontitis is caused by bacterial plaque. The oral microflora may interact with the intestinal microflora and play a role in the development of periodontitis. The periodontal inflamed surface area (PISA) has been shown to be a useful indicator of periodontal disease related to systemic diseases; however, few studies have shown an association between PISA and the bacterial flora. This study aimed to determine the association between PISA and oral and intestinal bacteria. Methods: Participants were recruited between 2018 and 2021 at the Medical and Dental Collaboration Center of Kanagawa Dental University Hospital. A periodontal clinical examination was performed, and the PISA was calculated. Salivary tests were conducted, and leukocyte scores in the saliva were calculated. Moreover, 16S rRNA amplicon sequencing was performed using saliva and stool samples to analyze oral and intestinal bacteria, respectively. Results: Higher PISA levels resulted in an increased presence of Bacteroides and a decreased presence of Proteobacteria and Actinobacteria in the saliva. An increase in Bacteroides was detected in the saliva of patients with high leukocyte scores. No correlation was observed between PISA and intestinal bacteria. Conclusions: Bacteroides was highly abundant in the saliva of patients with worsened periodontal conditions, as indicated by PISA. No association was found between PISA and intestinal bacteria.

Berberine alleviates high-energy and low-protein diet-induced fatty liver hemorrhagic syndrome in laying hens: insights from microbiome and metabolomics

Berberine (BBR), a well-known quaternary ammonium alkaloid, is recognized for its ability to prevent and alleviate metabolic disorders because of its anti-oxidative and anti-inflammatory properties. However, the underlying mechanisms of BBR to mitigate fatty liver hemorrhagic syndrome (FLHS) through the modulation of gut microbiota and their metabolism remained unclear. The results revealed that BBR ameliorates lipid metabolism disorder in high-energy and low-protein (HELP) diet-induced FLHS laying hens, as evidenced by improved liver function and lipid deposition of the liver, reduced blood lipids, and the expression of liver lipid synthesis-related factors. Moreover, BBR alleviated HELP diet-induced barrier dysfunction, increased microbial population, and dysregulated lipid metabolism in the ileum. BBR reshaped the HELP-perturbed gut microbiota, particularly declining the abundance of Desulfovibrio_piger and elevating the abundance of Bacteroides_salanitronis_DSM_18170. Meanwhile, metabolomic profiling analysis revealed that BBR reshaped microbial metabolism and function, particularly by reducing the levels of hydrocinnamic acid, dehydroanonaine, and leucinic acid. Furthermore, fecal microbiota transplantation (FMT) experiments revealed that BBR-enriched gut microbiota alleviated hepatic lipid deposition and intestinal inflammation compared with those chicks that received a gut microbiota by HELP. Collectively, our study provided evidence that BBR effectively alleviated FLHS induced by HELP by reshaping the microbial and metabolic homeostasis within the liver-gut axis.

Gut Microbiota Profile Changes in Patients with Inflammatory Bowel Disease and Non-Alcoholic Fatty Liver Disease: A Metagenomic Study

Gut microbiota imbalances have a significant role in the pathogenesis of Inflammatory Bowel Disease (IBD) and Non-Alcoholic Fatty Liver Disease (NAFLD). Herein, we compared gut microbial composition in patients diagnosed with either IBD or NAFLD or a combination of both. Seventy-four participants were stratified into four groups: IBD-NAFLD, IBD-only, NAFLD-only patients, and healthy controls (CTRLs). The 16S rRNA was sequenced by Next-Generation Sequencing. Bioinformatics and statistical analysis were performed. Bacterial α-diversity showed a significant lower value when the IBD-only group was compared to the other groups and particularly against the IBD-NAFLD group. β-diversity also showed a significant difference among groups. The higher Bacteroidetes/Firmicutes ratio was found only when comparing IBD groups and CTRLs. Comparing the IBD-only group with the IBD-NAFLD group, a decrease in differential abundance of Subdoligranulum, Parabacteroides, and Fusicatenibacter was found. Comparing the NAFLD-only with the IBD-NAFLD groups, there was a higher abundance of Alistipes, Odoribacter, Sutterella, and Lachnospira. An inverse relationship in the comparison between the IBD-only group and the other groups was shown. For the first time, the singularity of the gut microbial composition in IBD and NAFLD patients has been shown, implying a potential microbial signature mainly influenced by gut inflammation.

Extracellular vesicles from periodontal pathogens regulate hepatic steatosis via Toll-like receptor 2 and plasminogen activator inhibitor-1

Plasminogen activator inhibitor-1 (PAI-1) is associated with nonalcoholic fatty liver disease (NAFLD) by lipid accumulation in the liver. In this study, we showed that extracellular vesicles (EVs) from the periodontal pathogens Filifactor alocis and Porphyromonas gingivalis induced steatosis by inducing PAI-1 in the liver and serum of mice fed a low-fat diet. PAI-1 induction was not observed in TLR2-/- mice. When tested using HEK-Blue hTLR2 cells, human TLR2 reporter cells, the TLR2-activating ability of serum from NAFLD patients (n = 100) was significantly higher than that of serum from healthy subjects (n = 100). Correlation analysis confirmed that PAI-1 levels were positively correlated with the TLR2-activating ability of serum from NAFLD patients and healthy subjects. Amphiphilic molecules in EVs were involved in PAI-1 induction. Our data demonstrate that the TLR2/PAI-1 axis is important for hepatic steatosis by EVs of periodontal pathogens.