Periodontal Pathogens: A Crucial Link Between Periodontal Diseases and Oral Cancer

MnFe@N-CNTs Based Lactate Biomicrochips for Nonintrusive and Onsite Periodontitis Diagnosis

In clinical settings, saliva has been established as a straightforward, noninvasive medium for diagnosing periodontitis. However, the precise diagnosis is often hampered by the absence of a specialized analyzer capable of detecting low concentrations of biomarkers typically found in saliva. In this study, we present a noninvasive, on-site screen-printed biomicrochip specifically engineered for the precise and sensitive quantification of lactate concentrations in saliva, a critical biomarker in the diagnosis of periodontitis. The microchip is constructed using a nanostructured ink formulation that includes MnFe@N-doped carbon nanotubes (MnFe@N-CNTs). These MnFe@N-CNTs exhibit a high degree of graphitization and low electrical resistance, significantly augmenting the electrocatalytic efficiency of the enzymatic reaction of lactate. This results in doubled sensitivity and a detection limit that surpasses those of the current advanced salivary assay methods. Remarkably, within just 30 s, the biomicrochip can quantitatively and precisely measure lactate concentrations in the saliva of 10 patients, which provides valuable insights into the severity of their periodontitis. This biosensor holds excellent potential for large-scale production and could broaden the scope of biomarker recognition, paving the way for the analysis of a wider range of oral diseases.

Oral-Gut-Estrobolome Axis May Exert a Selective Impact on Oral Cancer

A subset of bacterial species that holds genes encoding for β-glucuronidase and β-galactosidase, enzymes involved in the metabolism of conjugated estrogens, is called the "estrobolome." There is an emerging interest embracing this concept, as it may exert a selective impact on a number of pathologies, including oral cancer. Although the estrobolome bacteria are typically part of the gut microbiota, recent experimental pieces of evidence have suggested a crosstalk among oral and gut microbiota. In fact, several oral bacterial species are well represented also in the gut microbiota, and these microbes can effectively induce the estrobolome activation. The main pathways used for activating the estrobolome are based on the induction of the expression patterns for 2 bacterial enzymes: β-glucuronidase and aromatase, both involved in the increase of estrogen released in the bloodstream and consequently in the salivary compartment. Mechanistically, high estrogen availability in saliva is responsible for an increase in oral cancer risk for different reasons: briefly, 1) estrogens directly exert biological and metabolic effects on oral mucosa cells; 2) they can modulate the pathological profile of some bacteria, somewhere associated with neoplastic processes (i.e., Fusobacterium spp., Parvimonas ssp.); and 3) some oral bacteria are able to convert estrogens into carcinogenic metabolites, such as 4-hydroxyestrone and 16α-hydroxyestrone (16α-OHE), and can also promote local and systemic inflammation. Nowadays, only a small number of scientific studies have taken into consideration the potential correlations among oral dysbiosis, alterations of the gut estrobolome, and some hormone-dependent cancers: this lack of attention on such a promising topic could be a bias affecting the full understanding of the pathogenesis of several estrogen-related oral pathologies. In our article, we have speculated on the activity of an oral-gut-estrobolome axis, capable of synergizing these 2 important microbiotas, shedding light on a pilot hypothesis requiring further research.

Metabolomics and metagenomics reveal the impact of γδ T inhibition on gut microbiota and metabolism in periodontitis-promoting OSCC

During the process of periodontitis-promoting oral squamous cell carcinoma (OSCC), the periodontitis microbiota can facilitate OSCC development by activating γδ T cells. Inhibiting γδ T cells through immunotherapy has been shown to significantly alleviate various types of cancer. However, the underlying mechanism by which inhibiting γδ T cells influenced cancer treatment has not been fully elucidated. In this study, a mouse model of OSCC with periodontitis was established, and γδ T cells were inhibited by antibodies. Gut samples from the mice were collected and analyzed by metabolomics, metagenomics, and 16S rRNA. Integrative analysis of the gut metabolome and microbiome revealed that targeting γδ T resulted in changes in the levels of metabolites associated with cancer in the gut. Although there was no difference in the α diversity of microbiota, β diversity was significantly different, with a more heterogeneous community structure in the mice receiving targeted γδ T immunotherapy. Statistical analysis of the gut microbiota at the species level revealed a significant enrichment of Lactobacillus murinus, which was significantly correlated with γδ T abundance. The functional analysis revealed that inhibiting γδ T could impact the functional gene. A comprehensive analysis revealed that L. murinus is especially associated with changes in adenine, which also had connection with the concentration of IL-17 and the abundance of γδ T.IMPORTANCEThis study revealed the effect of γδ T cells on gut microbial dysbiosis and identify potential links between gut microbiota and metabolism, providing new insights into the role of γδ T during the process of periodontitis-induced OSCC, and identifying relevant biomarkers for future research and clinical monitoring protocol development.

Green tea extracts alleviate acetic acid-induced oral inflammation and reconstruct oral microbial balance in mice

Oral cavity contains the second largest microbial community in the human body. Due to the highly vascularized feature of mouth, oral microbes could directly access the bloodstream and affect the host healthy systemically. The imbalance of oral microbiota is closely related to various oral and systemic diseases. Green tea extracts (GTE) mainly contain tea polyphenols, alkaloids, amino acid, flavones, and so on, which equipped with excellent anti-inflammatory activities. Previous studies have demonstrated the beneficial effects of GTE on oral health. However, most researches used in vitro models or focused on limited microorganisms. In this study, the regulatory effect of GTE on oral microbiome and the alleviative effect on oral inflammation in vivo were evaluated. The results showed that GTE could efficiently alleviate the inflammations of the tongue, cheek pouch, as well as throat. GTE effectively inhibited the activation of NF-κB through the upregulation of the anti-inflammatory cytokine interleukin (IL)-10, consequently leading to reduced expression of pro-inflammatory cytokines IL-6 and tumor necrosis factor-α. The indexes of spleen and thymus were also elevated by GTE in stomatitis mice. Moreover, GTE promoted the growth of probiotics Lactobacillus and Bacillus, inhibited the reproduction of pathogens Achromobacter, reversing the microbiota disorders in oral cavity. This study not only presents a novel approach for enhancing oral microecology but also facilitates the wider adoption of tea consumption.

Novel insights into IL-37: an anti-inflammatory cytokine with emerging roles in anti-cancer process

Interleukin-37 (IL-37) is a newly discovered member of IL-1 family. The cytokine was proved to have extensive protective effects in infectious diseases, allergic diseases, metabolic diseases, autoimmune diseases and tumors since its discovery. IL-37 was mainly produced by immune and some non-immune cells in response to inflammatory stimulus. The IL-37 precursors can convert into the mature forms after caspase-1 cleavage and activation intracellularly, and then bind to Smad-3 and transfer to the nucleus to inhibit the production and functions of proinflammatory cytokines; extracellularly, IL-37 binds to cell surface receptors to form IL-37/IL-18Rα/IL-1R8 complex to exert immunosuppressive function via inhibiting/activating multiple signal pathways. In addition, IL-37 can attenuate the pro-inflammatory effect of IL-18 through directly or forming an IL-37/IL-18BP/IL-18Rβ complex. Therefore, IL-37 has the ability to suppress innate and acquired immunity of the host, and effectively control inflammatory stimulation, which was considered as a new hallmark of cancer. Specifically, it is concluded that IL-37 can inhibit the growth and migration of tumor cells, prohibit angiogenesis and mediate the immunoregulation in tumor microenvironment, so as to exert effective anti-tumor effects. Importantly, latest studies also showed that IL-37 may be a novel therapeutic target for cancer monitoring. In this review, we summarize the immunoregulation roles and mechanisms of IL-37 in anti-tumor process, and discuss its progress so far and potential as tumor immunotherapy.

Microbial Changes Associated With Oral Cavity Cancer Progression

OBJECTIVE

To examine the oral microbiome in the context of oral cavity squamous cell carcinoma.

STUDY DESIGN

Basic science research.

SETTING

Academic medical center.

METHODS

Oral swabs were collected from patients presenting to the operating room for management of oral cavity squamous cell carcinoma and from age- and sex-matched control patients receiving surgery for unrelated benign conditions. 16S ribosomal RNA (rRNA) sequencing was performed on genetic material obtained from swabs. A bacterial rRNA gene library was created and sequence reads were sorted into taxonomic units.

RESULTS

Thirty-one control patients (17 males) and 35 cancer patients (21 males) were enrolled. Ages ranged from 23 to 89 (median 63) for control patients and 35 to 86 (median 66) for cancer patients. Sixty-one percent of control patients and 63% of cancer patients were smokers. 16S analyses demonstrated a significant decrease in Streptococcus genera in oral cancer patients (34.11% vs 21.74% of the population, p = .04). Increases in Fusobacterium, Peptostreptococcus, Parvimonas, and Neisseria were also found. The abundance of these bacteria correlated with tumor T-stage.

CONCLUSION

16S rRNA sequencing demonstrated changes in bacterial populations in oral cavity cancer and its progression compared to noncancer controls. We found increases in bacteria genera that correspond with tumor stage-Fusobacteria, Peptostreptococcus, Parvimonas, Neisseria, and Treponema. These data suggest that oral cancer creates an environment to facilitate foreign bacterial growth, rather than implicating a specific bacterial species in carcinogenesis. These bacteria can be employed as a potential marker for tumor progression or interrogated to better characterize the tumor microenvironment.

Growth Conditions Influence Lactobacillus Cell-Free Supernatant Impact on Viability, Biofilm Formation, and Co-Aggregation of the Oral Periodontopathogens Fusobacterium nucleatum and Porphyromonas gingivalis

Fusobacterium nucleatum and Porphyromonas gingivalis human periodontopathogens play a leading part in oral squamous cell carcinoma through cell proliferation, invasion, and persistent inflammation promotion and maintenance. To explore how the activity of Lactobacillus-derived cell-free supernatants (CFSs) can be influenced by growth medium components, CFSs were produced both in the standard MRS and the novel animal-derivative-free “Terreno Industriale Lattobacilli” (TIL) media, and in vitro screened for the containment of F. nucleatum and P. gingivalis both single and co-cultured and also for the interference on their co-aggregation. The viability assay demonstrated that the Limosilactobacillus reuteri LRE11 and Ligilactobacillus salivarius LS03 MRS-produced CFSs were significantly more effective against single and co-cultured pathogens. All the other CFSs significantly improved their efficacy when produced in TIL. Both MRS- and TIL-produced CFSs significantly inhibited the single and co-cultured pathogen biofilm formation. Only Levilactobacillus brevis LBR01 CFS in MRS specifically reduced F. nucleatum and P. gingivalis co-aggregation, while viable LBR01, LS03, and LRE11 in MRS significantly co-aggregated with the pathogens, but only LS03 cultivated in TIL improved this effect. This work paves the way to better consider environmental growth conditions when screening for probiotic and postbiotic efficacy as crucial to pathogen aggregation, adhesion to the host’s niches, and exclusion.