Could Periodontal Disease through Periopathogen Fusobacterium Nucleatum be an Aggravating Factor for Gastric Cancer?

Periodontitis: etiology, conventional treatments, and emerging bacteriophage and predatory bacteria therapies

Inflammatory periodontal diseases associated with the accumulation of dental biofilm, such as gingivitis and periodontitis, are very common and pose clinical problems for clinicians and patients. Gingivitis is a mild form of gum disease and when treated quickly and properly is completely reversible. Periodontitis is an advanced and irreversible disease of the periodontium with periods of exacerbations, progressions and remission. Periodontitis is a chronic inflammatory condition that damages the tissues supporting the tooth in its socket, i.e., the gums, periodontal ligaments, root cementum and bone. Periodontal inflammation is most commonly triggered by bacteria present in excessive accumulations of dental plaque (biofilm) on tooth surfaces. This disease is driven by disproportionate host inflammatory immune responses induced by imbalance in the composition of oral bacteria and changes in their metabolic activities. This microbial dysbiosis favors the establishment of inflammatory conditions and ultimately results in the destruction of tooth-supporting tissues. Apart microbial shift and host inflammatory response, environmental factors and genetics are also important in etiology In addition to oral tissues destruction, periodontal diseases can also result in significant systemic complications. Conventional methods of periodontal disease treatment (improving oral hygiene, dental biofilm control, mechanical plaque removal, using local or systemic antimicrobial agents) are not fully effective. All this prompts the search for new methods of therapy. Advanced periodontitis with multiple abscesses is often treated with antibiotics, such as amoxicillin, tetracycline, doxycycline, minocycline, clindamycin, or combined therapy of amoxicillin with metronidazole. However, due to the growing problem of antibiotic resistance, treatment does not always achieve the desired therapeutic effect. This review summarizes pathogenesis, current approaches in treatment, limitations of therapy and the current state of research on the possibility of application of bacteriophages and predatory bacteria to combat bacteria responsible for periodontitis. We present the current landscape of potential applications for alternative therapies for periodontitis based on phages and bacteria, and highlight the gaps in existing knowledge that need to be addressed before clinical trials utilizing these therapeutic strategies can be seriously considered.

Global Research Trends in the Links between Periodontal Disease and Cancer: A Bibliometric Analysis

Both periodontal disease and cancer are prevalent conditions with significant impacts on individuals and society. Extensive research has suggested a potential link between these two diseases. This study conducted a bibliometric analysis using the Thomson Reuters Web of Science Core Collection database, focusing on publications from 2014 to 2023. The analysis included data extraction and examination of authors, affiliations, publication dates, journals, countries, citation counts, keywords, and the H-index. A total of 253 relevant articles were identified, showing an increasing trend in both publications and citations over the years. The analysis highlighted the most productive authors, institutions, and countries/regions, with Michaud DS and Abnet CC leading in the number of publications. Highly cited articles emphasized the role of specific oral microbiota, particularly F. nucleatum and P. gingivalis, in various cancers, suggesting their potential as diagnostic markers and therapeutic targets. Four key thematic clusters emerged from the keyword analysis: the broader health implications of periodontal disease, the microbiome's role in carcinogenesis, inflammation, and specific bacteria in cancer, and epidemiological methods in studying the disease-cancer association. This bibliometric analysis underscores the growing interest in the connection between periodontal disease and cancer. Future research should adopt interdisciplinary approaches, focus on large-scale microbiome studies and longitudinal research to understand the systemic effects of periodontal disease, identify cancer-associated bacterial profiles, and investigate the molecular mechanisms of bacterial carcinogenesis. Additionally, public health interventions aimed at improving oral hygiene and reducing cancer risk factors are recommended.

Microbiome reveals inflammatory-related bacteria and putative functional pathways involved in human papillomavirus-associated penile squamous cell carcinoma

BACKGROUND

Penile squamous cell carcinoma (PSCC) is a rare disease that is more prevalent in developing countries, such as Brazil, and is linked to poor genital hygiene, which promotes the proliferation of microorganisms. Dysbiosis has an effect on the local immune response, increases the risk of viral infection, and can generate inflammatory processes. Current knowledge of the microbiota found in penile tissues is limited, and the bacterial diversity of the PSCC remains unknown. In this investigation, the microbiota associated with penile cancer and its potential role in tumor development and progression were identified.

METHODS

The 16S rRNA gene was analyzed by next-generation sequencing in 19 tumors and their respective non-tumor adjacent tissues to perform taxonomic classification, analysis of core microbiome, abundance, and diversity of amplicon sequence variants (ASVs) (QIIME2 v.2020.2), and in silico functional prediction (PICRUST2, p < 0.05).

RESULTS

In both tissues, the phyla Proteobacteria and Firmicutes, and genera Alcaligenes and Fusobaterium, were the most prevalent. Tumors presented a greater relative abundance of Fusobacteriota, Campilobacteria, and Fusobacterium (p = 0.04, p = 0.04, and p = 0.039, respectively). In addition, the beta diversity analysis revealed a tendency for the formation of two distinct groups when only advanced tumors (pT2 and pT3) were considered. Further, the functional analysis identified the top 35 pathways, and 79.5% of PSCC samples contained pro-inflammatory microorganisms.

CONCLUSION

We describe the first microbiome of penile carcinoma, which revealed an abundant and diverse microbiota as well as inflammatory-related taxa (the phyla Proteobacteria and Firmicutes, the genera Fusobacterium and Prevotella, and the species Finegoldia magma and Pseudomonas geniculata) and molecular pathways (chitin derivates degradation, the protocatechuic acid pathway, inositol metabolism, and the sucrose pathway), which have also been linked to inflammation and carcinogenesis. Moreover, we found specific and abundant ASVs in both tumor and non-tumor tissues. Our data encourage further study to better understand the role of these microorganisms in penile carcinogenesis, offering an opportunity for advances in diagnosis, prognosis, and early therapy.

Fusobacterium nucleatum: An Overview of Evidence, Demi-Decadal Trends, and Its Role in Adverse Pregnancy Outcomes and Various Gynecological Diseases, including Cancers

Gynecological and obstetric infectious diseases are crucial to women's health. There is growing evidence that links the presence of Fusobacterium nucleatum (F. nucleatum), an anaerobic oral commensal and potential periodontal pathogen, to the development and progression of various human diseases, including cancers. While the role of this opportunistic oral pathogen has been extensively studied in colorectal cancer in recent years, research on its epidemiological evidence and mechanistic link to gynecological diseases (GDs) is still ongoing. Thus, the present review, which is the first of its kind, aims to undertake a comprehensive and critical reappraisal of F. nucleatum, including the genetics and mechanistic role in promoting adverse pregnancy outcomes (APOs) and various GDs, including cancers. Additionally, this review discusses new conceptual advances that link the immunomodulatory role of F. nucleatum to the development and progression of breast, ovarian, endometrial, and cervical carcinomas through the activation of various direct and indirect signaling pathways. However, further studies are needed to explore and elucidate the highly dynamic process of host-F. nucleatum interactions and discover new pathways, which will pave the way for the development of better preventive and therapeutic strategies against this pathobiont.

Potential Common Molecular Mechanisms Between Periodontitis and Hepatocellular Carcinoma: A Bioinformatic Analysis and Validation

BACKGROUND/AIM

Hepatocellular carcinoma (HCC) is the most common primary liver cancer and has a poor prognosis. Periodontitis, or tooth loss, is considered to be related to hepatocarcinogenesis and its poor prognosis. This study aimed to explore potential associations and cross-talk mechanisms between periodontitis and HCC.

MATERIALS AND METHODS

Periodontitis and HCC microarray datasets were acquired from the Gene Expression Omnibus (GEO) database and were analyzed to obtain differentially expressed (DE) lncRNAs, miRNAs and mRNAs. Functional enrichment analysis was used to detect the functions of these mRNAs. Then, a ceRNA network of periodontitis-related HCC was constructed. Least absolute shrinkage and selection operator (LASSO) regression, random forest algorithm, and support vector machine-recursive feature elimination (SVM-RFE) were performed to explore the diagnostic significance of mRNAs in periodontitis-related HCC. Cox regression analyses were conducted to screen mRNAs with prognostic significance in HCC. Quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC) were conducted to validate the expression of these mRNAs in HCC tissues.

RESULTS

A ceRNA network was constructed. Functional enrichment analysis indicated that the network is associated with immune and inflammatory responses, the cell cycle and liver metabolic function. LASSO, random forest algorithm and SVM-RFE showed the diagnostic significance of DE mRNAs in HCC. Cox regression analyses revealed that MSH2, GRAMD1C and CTHRC1 have prognostic significance for HCC, and qRT-PCR and IHC validated this finding.

CONCLUSION

Periodontitis may affect the occurrence of HCC by changing the immune and inflammatory response, the cell cycle and liver metabolic function. MSH2, GRAMD1C and CTHRC1 are potential prognostic biomarkers for HCC.

Microbiota and gastric cancer

The discovery of Helicobacter pylori in 1982 drew to an end the stomach being considered as a sterile organ. Later, the progress in molecular methods, especially Next Generation Sequencing and metagenomics, has highlighted the fact that a diverse microbiota including five major phyla could also be present in the stomach. However, when present, H. pylori is the essential species and it influences the other bacterial communities in terms of richness and evenness. It is now well accepted that H. pylori is the main risk factor for gastric cancer, especially the strains harboring the cag pathogenicity island and the CagA oncoprotein, but the need for other factors from the host and the environment can explain the important difference between those infected and those developing gastric cancer. Several studies showed a difference between the gastric microbiota of patients at various stages of development of gastric premalignant and malignant lesions, showing globally a reduced microbial diversity and an increase in the presence of intestinal commensals, especially with nitrosative functions. Other studies showed an increase in oral microbiota. These data suggest that the gastric microbiota other than H. pylori may play a role in the last steps of gastric carcinogenesis. It must also be noted that in a limited number of cases, a virus: the Epstein Barr Virus is responsible for the evolution toward gastric cancer, while in others the mycobiota also needs to be explored. Finally, the use of mice models allowed an exploration of the role of different gastric microbiota in addition to H. pylori.

Periodontitis may induce gut microbiota dysbiosis via salivary microbiota

The aim of this study was to identify whether periodontitis induces gut microbiota dysbiosis via invasion by salivary microbes. First, faecal and salivary samples were collected from periodontally healthy participants (PH group, n = 16) and patients with severe periodontitis (SP group, n = 21) and analysed by 16S ribosomal RNA sequencing. Significant differences were observed in both the faecal and salivary microbiota between the PH and SP groups. Notably, more saliva-sourced microbes were observed in the faecal samples of the SP group. Then, the remaining salivary microbes were transplanted into C57BL6/J mice (the C-PH group and the C-SP group), and it was found that the composition of the gut microbiota of the C-SP group was significantly different from that of the C-PH group, with Porphyromonadaceae and Fusobacterium being significantly enriched in the C-SP group. In the colon, the C-SP group showed significantly reduced crypt depth and zonula occludens-1 expression. The mRNA expression levels of pro-inflammatory cytokines, chemokines and tight junction proteins were significantly higher in the C-SP group. To further investigate whether salivary bacteria could persist in the intestine, the salivary microbiota was stained with carboxyfluorescein diacetate succinimidyl ester and transplanted into mice. We found that salivary microbes from both the PH group and the SP group could persist in the gut for at least 24 h. Thus, our data demonstrate that periodontitis may induce gut microbiota dysbiosis through the influx of salivary microbes.

Comparative and analytical characterization of the oral bacteriome of smokeless tobacco users with oral squamous cell carcinoma

Oral cavity squamous cell carcinoma (OSCC) is the most common type of head and neck cancer worldwide. Smokeless tobacco (SLT) has been well proven for its role in oral carcinogenesis due to the abundance of several carcinogens. However, the role of inhabitant microorganisms in the oral cavity of smokeless tobacco users has not yet been well explored in the context of OSCC. Therefore, the present investigation was conceived to analyze the oral bacteriome of smokeless tobacco users having OSCC (CP group). With the assistance of illumina-based sequencing of bacterial-specific V3 hypervariable region of 16S rDNA gene, 71,969 OTUs (operational taxonomic units) were categorized into 18 phyla and 166 genera. The overall analysis revealed that the oral bacteriome of the patients with OSCC, who were smokeless tobacco users, was significantly different compared to the healthy smokeless tobacco users (HTC group) and non-users (HI users). The appearance of 14 significantly abundant genera [FDR (false discovery rate) adjusted probability value of significance (p value) < 0.05] among the CP group showed the prevalence of tobacco-specific nitrosamines forming bacteria (Staphylococcus, Fusobacterium, and Campylobacter). The functional attributes of the oral bacteriome of the CP group can also be correlated with the genes involved in oncogenesis. This study is the first report on the oral bacteriome of Indian patients with OSCC who were chronic tobacco chewers. The results of the present study will pave the way to understand the influence of smokeless tobacco on the oral bacteriome of OSCC patients. KEY POINTS: • Oral bacteriome of OSCC patients differ from healthy smokeless tobacco (SLT) users and SLT non-users. • Smokeless tobacco influences the oral bacteriome of OSCC group. • Oral bacteriome specific diagnostics may be developed for pre-diagnosis of oral cancer.

Fusobacterium nucleatum and cancer

Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor‐promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor‐specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment.

Association of short sleep with risk of periodontal disease: A meta-analysis and Mendelian randomization study

AIM

The aim of this meta-analysis and Mendelian randomization (MR) study was to assess the association between short sleep and periodontal disease, including tooth loss and periodontitis.

MATERIALS AND METHODS

The meta-analysis of relevant studies was conducted to assess the association between short sleep and periodontal disease. MR analyses were conducted with the inverse-variance-weighted (IVW) method, weighted median method, MR-Egger method, and MR-Robust Adjusted Profile Score (RAPS) method to assess the causal effect of short sleep on tooth loss and periodontitis.

RESULTS

Seven cross-sectional studies involving 40,196 individuals were included in the meta-analysis. The association between short sleep and periodontal disease was not statistically significant (odds ratios (OR) =1.13, 95% confidence interval (CI): 0.99, 1.28; p = 0.076). In the MR analysis, we did not observe statistically significant causal associations of genetically determined short sleep with tooth loss (β: -0.056; 95% CI: -0.181 to 0.068; p = 0.376) and periodontitis (β: -0.112; 95% CI: -0.340 to 0.117; p = 0.339).

CONCLUSIONS

Short sleep is not associated with the risk of periodontal disease according to current evidence. Future studies need to pay attention to the measurement of sleep duration, the choice of statistical models, and other domains of sleep health.