Lactobacilli Attenuate the Effect of Aggregatibacter actinomycetemcomitans Infection in Gingival Epithelial Cells

The Oral-Gut-Brain Axis: The Influence of Microbes as a Link of Periodontitis With Ischemic Stroke

Periodontitis, a non-communicable chronic inflammation disease resulting from dysbiosis of the oral microbiota, has been demonstrated to have a positive association with the risk of ischemic stroke (IS). The major periodontal pathogens contribute to the progression of stroke-related risk factors such as obesity, diabetes, atherosclerosis, and hypertension. Transcriptional changes in periodontitis pathogens have been detected in oral samples from stroke patients, suggesting a new conceptual framework involving microorganisms. The bidirectional regulation between the gut and the central nervous system (CNS) is mediated by interactions between intestinal microflora and brain cells. The connection between the oral cavity and gut through microbiota indicates that the oral microbial community may play a role in mediating complex communication between the oral cavity and the CNS; however, underlying mechanisms have yet to be fully understood. In this review, we present an overview of key concepts and potential mechanisms of interaction between the oral-gut-brain axis based on previous research, focusing on how the oral microbiome (especially the periodontal pathogens) impacts IS and its risk factors, as well as the mediating role of immune system homeostasis, and providing potential preventive and therapeutic approaches.

Live dietary microbes and reduced prevalence of periodontitis: A cross-sectional study

OBJECTIVE

Investigate the link between live dietary microbe consumption and the prevalence of periodontitis.

METHODS AND MATERIALS

National health and nutrition examination survey (2009-2014) data was used to assess the association among adults. Live dietary microbe intake was categorized as low or medium to high. Regression models were employed to assess this association, adjusting for demographic variables and other covariates. Examined dose-response relationship and conducted subgroup analyses by ethnicity, age and gender. Multiplicative interactions were evaluated using likelihood ratio tests.

RESULTS

The analysis included 8574 participants. After adjusting for various factors including age, gender, ethnicity, dietary habits, dietary inflammatory index, alcohol consumption, smoking status, hypertension, diabetes mellitus and oral health behaviors, individuals with daily intake of medium to high levels of live dietary microbes showed a significantly reduced risk of periodontitis compared to those who did not consume such microbes with a dose-response trend (p for trend <0.0001, p < 0.01). Significant differences in the impact of live microbe intake on periodontitis were also observed across different age groups in all Models (p for interaction ≤0.05).

CONCLUSION

Medium to high live dietary microbe consumption independently correlates with lower periodontitis risk, irrespective of traditional risk factors and demographics.

Advances in biomaterials for oral-maxillofacial bone regeneration: spotlight on periodontal and alveolar bone strategies

The intricate nature of oral-maxillofacial structure and function, coupled with the dynamic oral bacterial environment, presents formidable obstacles in addressing the repair and regeneration of oral-maxillofacial bone defects. Numerous characteristics should be noticed in oral-maxillofacial bone repair, such as irregular morphology of bone defects, homeostasis between hosts and microorganisms in the oral cavity and complex periodontal structures that facilitate epithelial ingrowth. Therefore, oral-maxillofacial bone repair necessitates restoration materials that adhere to stringent and specific demands. This review starts with exploring these particular requirements by introducing the particular characteristics of oral-maxillofacial bones and then summarizes the classifications of current bone repair materials in respect of composition and structure. Additionally, we discuss the modifications in current bone repair materials including improving mechanical properties, optimizing surface topography and pore structure and adding bioactive components such as elements, compounds, cells and their derivatives. Ultimately, we organize a range of potential optimization strategies and future perspectives for enhancing oral-maxillofacial bone repair materials, including physical environment manipulation, oral microbial homeostasis modulation, osteo-immune regulation, smart stimuli-responsive strategies and multifaceted approach for poly-pathic treatment, in the hope of providing some insights for researchers in this field. In summary, this review analyzes the complex demands of oral-maxillofacial bone repair, especially for periodontal and alveolar bone, concludes multifaceted strategies for corresponding biomaterials and aims to inspire future research in the pursuit of more effective treatment outcomes.

Microbiome-based therapies for periodontitis and peri-implantitis

OBJECTIVES

Periodontitis and peri-implantitis are oral infectious-inflammatory diseases associated with oral microbial dysbiosis. Microbiome-based therapies, characterized by manipulation of the microbiota, are emerging as promising therapeutic approaches to resolve the microbial dysbiosis and associated dysregulation of immune system. This review aims at summarizing recent progress on microbiome-based therapies in periodontitis and peri-implantitis, promoting a further understanding of the related therapeutic mechanisms.

SUBJECTS AND METHODS

Pertinent literatures focused on microbiome-based therapies for periodontitis and peri-implantitis are obtained from PubMed and Web of Science.

RESULTS

In this article, we review the roles and therapeutic mechanisms of four microbiome-based therapies, including probiotics, postbiotics, predatory bacteria and phages, and microbiota transplantation, in the management of periodontitis and peri-implantitis. Challenges facing this field are also discussed, highlighting the areas that require more attention and investigation.

CONCLUSIONS

Microbiome-based therapies may serve as effective treatment for periodontitis and peri-implantitis. This review presents a new viewpoint to this field.

Oral Administration of Lactobacillus acidophilus LA5 Prevents Alveolar Bone Loss and Alters Oral and Gut Microbiomes in a Murine Periodontitis Experimental Model

Periodontitis is a destructive inflammatory response triggered by dysbiosis. Lactobacillus acidophilus LA5 (LA5) may impair microbial colonization and alter the host. Thus, we evaluated the effect of LA5 on alveolar bone loss in a periodontitis murine model and investigated its effect on the oral and gut microbiomes. Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, and Streptococcus gordonii were inoculated in C57BL/6 mice (P+), with LA5 (L+). SHAM infected controls (P- and/or L- groups) were also evaluated. After 45 days, alveolar bone loss in the maxilla and oral and gut microbiomes were determined. The administration of LA5 controlled the microbial consortium-induced alveolar bone loss. Periodontopathogens infection resulted in shifts in the oral and gut microbiomes consistent with dysbiosis, and LA5 reshaped these changes. The oral microbiome of P+L- group showed the increased abundance of Enterococaccea, Streptoccocaceae, Staphylococcaceae, Moraxellaceae, and Pseudomonadaceae, which were attenuated by the administration of LA5 to the infected group (P+L+). The administration of LA5 to otherwise non-infected mice resulted in the increased abundance of the superphylum Patescibacteria and the family Saccharamonadaceae in the gut. These data indicate L. acidophilus LA5 as a candidate probiotic for the control of periodontitis.

Lactobacillus acidophilus LA-5 Ameliorates Inflammation and Alveolar Bone Loss Promoted by A. actinomycetemcomitans and S. gordonii in Mice and Impacts Oral and Gut Microbiomes

The benefits of probiotics on dysbiotic microbiomes and inflammation are dependent on the tested strain, host factors, and the resident microbiome. There is limited knowledge on the effects of probiotics in A. actinomycetemcomitans-associated periodontitis. Thus, Lactobacillus acidophilus LA5 (LA5) was orally inoculated for 30 days in C57Bl/6 mice infected with A. actinomycetemcomitans JP2 (Aa) and S. gordonii (Sg). Alveolar bone loss, gingival gene expression, and oral and gut microbiomes were determined. LA5 controlled bone loss in Aa+Sg-infected mice, downregulated the expression of Il-1β and upregulated Il-10 in gingival tissues, and altered the oral and gut microbiomes. LA5 increased the diversity of the oral microbiome of Aa+Sg infected mice, and Aa+Sg and Aa+Sg+LA5 oral or gut microbiomes clustered apart. LA5 induced shifts in Aa+Sg infected mice by increasing the abundance of Muribaculaceae and decreasing Bifidobacteriaceae in the oral cavity and increasing the abundance of Verrucomicrobiae and Eggerthellales in the gut. In conclusion, LA5 oral administration controls experimental Aa-associated periodontitis by altering inflammatory gene expression and the oral and gut microbiomes.

Safety Assessment and Probiotic Potential Comparison of Bifidobacterium longum subsp. infantis BLI-02, Lactobacillus plantarum LPL28, Lactobacillus acidophilus TYCA06, and Lactobacillus paracasei ET-66

Bifidobacterium longum subsp. infantis BLI-02, Lactobacillus paracasei ET-66, Lactobacillus plantarum LPL28, and Lactobacillus acidophilus TYCA06, isolated from healthy breast milk, miso, and the healthy human gut, were assessed for safety in this study. BLI-02, LPL28, TYCA06, and ET-66 exhibited no antibiotic resistance and mutagenic activity in the Ames test at the highest dosage (5000 μg/plate). No genotoxicity was observed in micronucleus and chromosomal aberration assays in rodent spermatogonia at the maximum dosage of 10 g/kg body weight (BW). No acute and sub-chronic toxicity occurred in mice and rats at the maximum tested dosage of 10 g/kg BW and 1.5 g/kg BW, respectively. The lyophilized powder of these strains survived a low pH and high bile salt environment, adhering strongly to Caco-2 cells. Unique antimicrobial activities were noted in these strains, with BLI-02 demonstrating the best growth inhibition against Vibrio parahaemolyticus, LPL28 exhibiting the best growth inhibition against Helicobacter pylori, and ET-66 showing the best growth inhibition against Aggregatibacter actinomycetemcomitans. Based on the present study, the lyophilized powder of these four strains appears to be a safe probiotic supplement at tested dosages. It should be applicable for clinical or healthcare applications.

Membrane Fluidity and Oxidative Stress in Patients with Periodontitis

Periodontitis leads to the destruction of dental tissue through polymicrobial interactions, inflammation, and increased oxidative stress. The aim of this study was to measure the levels of nitrates (NO3−), malondialdehyde (MDA), and membranal fluidity (MF) in the gingival tissue of subjects with or without periodontitis. A total of 120 participants from the Dentistry School of the University of Guadalajara were investigated. The study was approved by the ethics committee of our institution, with the registration number of CI-01221. The clinical parameters measured were probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BoP). NO3− was measured using the Greiss reaction, while MDA was determined colorimetrically with the FR12 Kit (Oxford Biomedical Research). Membrane fluidity (MF) was measured using the quotient Ie/Im according to the method of Ortiz and collaborators. The Student t-test, Spearman correlation, and chi-square are used to calculate the results. The results showed higher levels of PD, CAL, and BoP in patients. There was a positive correlation between MF and PD. Moreover, MDA was positively correlated with PD and CAL. Increases in PD resulted in higher levels of NO3−, MDA, and MF. Similarly, increases in CAL resulted in higher levels of MDA and MF in patients. We conclude that PD and CAL facilitated the progression of periodontitis through increases in MDA and MF.

Effect of Enterococcus faecalis OG1RF on human calvarial osteoblast apoptosis

Background

Enterococcus faecalis is a dominant pathogen in the root canals of teeth with persistent apical periodontitis (PAP), and osteoblast apoptosis contributes to imbalanced bone remodelling in PAP. Here, we investigated the effect of E. faecalis OG1RF on apoptosis in primary human calvarial osteoblasts. Specifically, the expression of apoptosis-related genes and the role of anti-apoptotic and pro-apoptotic members of the BCL-2 family were examined.

Methods

Primary human calvarial osteoblasts were incubated with E. faecalis OG1RF at multiplicities of infection corresponding to infection time points. Flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL) assay, caspase-3/-8/-9 activity assay, polymerase chain reaction (PCR) array, and quantitative real-time PCR were used to assess osteoblast apoptosis.

Results

E. faecalis infection increased the number of early- and late-phase apoptotic cells and TUNEL-positive cells, decreased the mitochondrial membrane potential (ΔΨm), and activated the caspase-3/-8/-9 pathway. Moreover, of all 84 apoptosis-related genes in the PCR array, the expression of 16 genes was upregulated and that of four genes was downregulated in the infected osteoblasts. Notably, the mRNA expression of anti-apoptotic BCL2 was downregulated, whereas that of the pro-apoptotic BCL2L11, HRK, BIK, BMF, NOXA, and BECN1 and anti-apoptotic BCL2A1 was upregulated.

Conclusions

E. faecalis OG1RF infection triggered apoptosis in human calvarial osteoblasts, and BCL-2 family members acted as regulators of osteoblast apoptosis. Therefore, BCL-2 family members may act as potential therapeutic targets for persistent apical periodontitis.