Exploration of Shared Gene Signatures and Molecular Mechanisms Between Periodontitis and Nonalcoholic Fatty Liver Disease

Periodontitis and NAFLD-related diseases: A bidirectional two-sample Mendelian randomization study

BACKGROUND

Epidemiological studies have shown an association between periodontitis and nonalcoholic fatty liver disease (NAFLD)-related diseases. However, a causal relationship between these two diseases remains unclear. To examine the causal relationship between these two diseases, we conducted a bidirectional two-sample Mendelian randomization (MR) analysis using genetic markers as proxies.

METHODS

Statistical summary was obtained from a large genome-wide association study (GWAS) on NAFLD (N = 342,499), nonalcoholic steatohepatitis (NASH, N = 342,499), fibrosis (N = 339,081), cirrhosis (N = 342,499), fibrosis/cirrhosis (N = 334,553), and periodontitis (N = 34,615) in the European ancestry. The inverse variance weighted (IVW) method was used as the main method to estimate the bidirectional association. Sensitivity analysis was performed to evaluate the rigidity of the results.

RESULTS

Limited evidence indicated positive causal associations between genetically predicted NAFLD and periodontitis (IVW odds ratio [OR], 1.094; 95% confidence interval [CI], 1.006-1.189; p = 0.036) and between cirrhosis and periodontitis (IVW OR, 1.138; 95% CI, 1.001-1.294; p = 0.048). However, the opposite trend did not indicate a causative effect of periodontitis on NAFLD-related diseases. The sensitivity analysis revealed no obvious pleiotropy or heterogeneity.

CONCLUSIONS

Our MR analysis provides new evidence in favor of the moderate causal impact of NAFLD on periodontitis. The causal effects of periodontitis on NAFLD-related diseases warrant further investigation.

Integrated liver and serum proteomics uncover sexual dimorphism and alteration of several immune response proteins in an aging Werner syndrome mouse model

Werner syndrome (WS) is a progeroid disorder caused by mutations in a protein containing both a DNA exonuclease and DNA helicase domains. Previous studies indicated that males lacking the helicase domain of the Wrn protein orthologue exhibited hepatic transcriptomic and metabolic alterations. In this study, we used a label-free liquid chromatography-tandem mass spectrometry approach to uncover proteins abundance associated with specific biological processes that differed depending on the age (four or ten months) and/or the genotype (wild type or Wrn mutant) in the serum and liver of mice. Principal component analysis of the proteomic data from both serum and hepatic tissue revealed a sexual dimorphism regardless of the age and the genotype of the mice. Moreover, although all Wrn mutant mice exhibited fatty liver by the age of ten months, a significant age and genotype dependent enrichment of proteins involved in lipid and fatty acid metabolic processes were uncovered only in males. Also, a genotype dependent increase in serum oxidant detoxification processes was observed in the serum of Wrn mutant males. Despite these sexual differences, several aspects of the immune system were affected in both females and males. Finally, an increase of specific immunoglobulin molecules was common in the liver and serum of both older Wrn mutant females and males. Such results suggest that specific immunoglobulin variants maybe associated with fatty liver progression in WS.

Activated platelets facilitate hematogenous metastasis of breast cancer by modulating the PDGFR-β/COX-2 axis

Platelets have been widely recognized as a bona fide mediator of malignant diseases, and they play significant roles in influencing various aspects of tumor progression. Paracrine interactions between platelets and tumor cells have been implicated in promoting the dissemination of malignant cells to distant sites. However, the underlying mechanisms of the platelet-tumor cell interactions for promoting hematogenous metastasis are not yet fully understood. We found that activated platelets with high expression of CD36 were prone to release a plethora of growth factors and cytokines, including high levels of PDGF-B, compared to resting platelets. PDGF-B activated the PDGFR-β/COX-2 signaling cascade, which elevated an array of pro-inflammatory factors levels, thereby aggravating tumor metastasis. The collective administration of CD36 inhibitor and COX-2 inhibitor resolved the interactions between platelets and tumor cells. Collectively, our findings demonstrated that targeting the crosstalk between platelets and tumor cells offers potential therapeutic strategies for inhibiting tumor metastasis.

Can Frequent Toothbrushing Reduce the Risk of Cirrhosis among Patients with Nonalcoholic Fatty Liver Disease? Hints from a Registry-Based Study

INTRODUCTION

While poor oral hygiene has been previously associated with an increased risk of nonalcoholic fatty liver disease (NAFLD), its association with hepatic fibrosis remains unclear. Here, we sought to analyze if toothbrushing frequency, an easy-to-assess indicator of oral health habits, would be associated with liver stiffness measurement (LSM) by transient elastography (TE) in patients with an established diagnosis of NAFLD.

METHODS

In this registry-based study, LSM was measured in 1,156 patients with NAFLD and analyzed in relation to the self-reported daily frequency of toothbrushing. LSM values ≥12 kPa were considered indicative of cirrhosis.

RESULTS

A trend toward a stepwise decrease (cross-sectional p = 0.13) in LSM was found in patients who reported having their teeth brushed more frequently: less than once a day (10.6 ± 8.6 kPa; 13% of the study sample), once a day (9.95 ± 8.40 kPa; 40%), twice a day (9.21 ± 7.63 kPa; 43%), and after every meal (8.91 ± 5.30 kPa; 4%). Patients who brushed their teeth less than once a day had a significantly higher prevalence of LSM values ≥12 kPa (p < 0.05). In multivariable logistic regression analysis, the association of LSM values ≥12 kPa with toothbrushing habits remained statistically significant for less than once a day (odds ratio = 1.69, 95% confidence interval = 1.07-2.66, p = 0.02) with reference to twice a day or after every meal.

CONCLUSION

Among patients with NAFLD, there is an independent association between brushing teeth less than once a day and TE-established cirrhosis.

Associations between Periodontal Status and Liver Function in the Japanese Population: A Cross-Sectional Study

A relationship between periodontitis and liver function has been suggested. Indeed, patients with severe periodontal disease have been found to be more prone to liver dysfunction. The periodontal inflammatory surface area (PISA) has been shown to be a useful indicator of periodontal and systemic diseases. However, little information is available regarding whether the PISA is associated with liver function markers, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST), and alanine aminotransferase (ALT). This study aimed to clarify relationship between liver function markers, AST, ALT, and GGT, and PISA level in a cross-sectional study. The subjects were recruited between 2018 and 2021 at the Medical and Dental Collaboration Center of Kanagawa Dental College Hospital. A periodontal clinical examination was performed, and the PISA was calculated. Peripheral blood samples were collected, and serum levels of liver function markers were measured. The levels of liver function markers were examined in different values of PISA. Participants with high PISA scores were more likely to have increased GGT levels while AST and ALT were not changed with PISA. Increased GGT was found in 10.8% and 29.4% (p = 0.0056), increased AST in 48.2% and 52.9% (p = 0.62), and increased ALT in 35.2% and 47.0% (p = 0.20) among <300 mm² and ≧300 mm² PISA groups, respectively. It was found that males with a PISA of 300 mm² or higher had an elevated level of serum GGT. In conclusion, elevated GGT was found in the high PISA group, particularly in males, while AST and ALT did not differ by PISA.

Role of oxidative stress in the relationship between periodontitis and systemic diseases

Periodontitis is a common inflammatory disease. It is characterized by destruction of the supporting structures of the teeth and could lead to tooth loss and systemic inflammation. Bacteria in inflamed gingival tissue and virulence factors are capable of entering the bloodstream to induce systemic inflammatory response, thus influencing the pathological process of many diseases, such as cardiovascular diseases, diabetes, chronic kidney disease, as well as liver injury. An increasing body of evidence show the complex interplay between oxidative stress and inflammation in disease pathogenesis. When periodontitis occurs, increased reactive oxygen species accumulation leads to oxidative stress. Oxidative stress contributes to major cellular components damage, including DNA, proteins, and lipids. In this article, the focus will be on oxidative stress in periodontal disease, the relationship between periodontitis and systemic inflammation, and the impact of periodontal therapy on oxidative stress parameters.

Identification and Evaluation of Hub Long Noncoding RNAs and mRNAs in High Fat Diet Induced Liver Steatosis

Nonalcoholic fatty liver disease (NAFLD) is considered the most prevalent chronic liver disease, but the understanding of the mechanism of NAFLD is still limited. The aim of our study was to explore hub lncRNAs and mRNAs and pathological processes in high-fat diet (HFD)-induced and lycopene-intervened liver steatosis. We analyzed the gene profiles in the GSE146627 dataset from the Gene Expression Omnibus (GEO) database to identify differentially expressed lncRNAs and mRNAs, and we constructed coexpression networks based on weighted gene coexpression network analysis (WGCNA). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases were utilized for functional enrichment analysis. We found that the turquoise, blue, brown, yellow, green, and black modules were significantly correlated with NAFLD. Functional enrichment analysis revealed that some hub lncRNAs (Smarca2, Tacc1, Flywch1, and Mef2c) might be involved in the regulation of the inflammatory and metabolic pathways (such as TNF signaling, metabolic, mTOR signaling, MAPK signaling, and p53 signaling pathways) in NAFLD. The establishment of an NAFLD mouse model confirmed that lycopene supply attenuated hepatic steatosis in HFD-induced NAFLD. Our analysis revealed that the inflammatory and metabolic pathways may be crucially involved in the pathogenesis of NAFLD, and hub lncRNAs provide novel biomarkers, therapeutic ideas, and targets for NAFLD. Moreover, lycopene has the potential to be a phytochemical for the prevention of HFD-induced liver steatosis.

FCGR2C: An emerging immune gene for predicting sepsis outcome

Background

Sepsis is a life-threatening disease associated with immunosuppression. Immunosuppression could ultimately increase sepsis mortality. This study aimed to identify the prognostic biomarkers related to immunity in sepsis.

Methods

Public datasets of sepsis downloaded from the Gene Expression Omnibus (GEO) database were divided into the discovery cohort and the first validation cohort. We used R software to screen differentially expressed genes (DEGs) and analyzed DEGs' functional enrichment in the discovery dataset. Immune-related genes (IRGs) were filtered from the GeneCards website. A Lasso regression model was used to screen candidate prognostic genes from the intersection of DEGs and IRGs. Then, the candidate prognostic genes with significant differences were identified as prognostic genes in the first validation cohort. We further validated the expression of the prognostic genes in the second validation cohort of 81 septic patients recruited from our hospital. In addition, we used four immune infiltration methods (MCP-counter, ssGSEA, ImmuCellAI, and CIBERSORT) to analyze immune cell composition in sepsis. We also explored the correlation between the prognostic biomarker and immune cells.

Results

First, 140 genes were identified as prognostic-related immune genes from the intersection of DEGs and IRGs. We screened 18 candidate prognostic genes in the discovery cohort with the lasso regression model. Second, in the first validation cohort, we identified 4 genes (CFHR2, FCGR2C, GFI1, and TICAM1) as prognostic immune genes. Subsequently, we found that FCGR2C was the only gene differentially expressed between survivors and non-survivors in 81 septic patients. In the discovery and first validation cohorts, the AUC values of FCGR2C were 0.73 and 0.67, respectively. FCGR2C (AUC=0.84) had more value than SOFA (AUC=0.80) and APACHE II (AUC=0.69) in evaluating the prognosis of septic patients in our recruitment cohort. Moreover, FCGR2C may be closely related to many immune cells and functions, such as B cells, NK cells, neutrophils, cytolytic activity, and inflammatory promotion. Finally, enrichment analysis showed that FCGR2C was enriched in the phagosome signaling pathway.

Conclusion

FCGR2C could be an immune biomarker associated with prognosis, which may be a new direction of immunotherapy to reduce sepsis mortality.

Assessment of independent variables of periodontal disease among selected South Indian population

Periodontal diseases are chronic diseases that affect the surrounding tissues of the teeth and the alveolar bone. As the disease progresses, it can lead to tooth loss. Several risk factors may increase the risk of periodontal disease. The objective of the study was to assess the independent variables of periodontal disease among the few of the Southern population of India. The current study was done on 155 patients who visited Saveetha Dental College and Hospitals. Data of demographic details (age, gender, educational status) and periodontal status (clinically healthy gingiva, gingivitis, and periodontitis) were recorded. The demographic and the periodontal parameters were associated using Chi-square test (SPSS Software, Version 23.0). 20-30-year-old patients were mostly affected with gingivitis (25.8%) and 51-60-year-old patients were affected with periodontitis (22.58%). This showed statistical significance (P < 0.05). More males were affected with periodontal diseases than females and were statistically insignificant (P > 0.05). Periodontitis was more common among illiterates (26.45%) and was statistically significant (P < 0.05). The study shows that periodontitis was predominantly seen among males of 51-60 years of age and illiterates. The results of the study reveal a positive association between age, gender, and educational status of patients with their periodontal health.