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Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

IntroductionPeriodontitis-related oral microbial dysbiosis is thought to contribute to Alzheimer's disease (AD) neuroinflammation and brain amyloid production. Since probiotics can modulate periodontitis/oral dysbiosis, this study examined the effects of a probiotic/lantibiotic, nisin, in modulating brain pathology triggered by periodontitis.MethodsA polymicrobial mouse model of periodontal disease was used to evaluate the effects of this disease on brain microbiome dysbiosis, neuroinflammation, Alzheimer's-related changes, and nisin's therapeutic potential in this context.Results16S sequencing and real-time PCR data revealed that Nisin treatment mitigated the changes in the brain microbiome composition, diversity, and community structure, and reduced the levels of periodontal pathogen DNA in the brain induced by periodontal disease. Nisin treatment significantly decreased the mRNA expression of pro-inflammatory cytokines (Interleukin-1β/IL-1 β, Interleukin 6/IL-6, and Tumor Necrosis Factor α/TNF-α) in the brain that were elevated by periodontal infection. In addition, the concentrations of amyloid-β 42 (Aβ42), total Tau, and Tau (pS199) (445.69 ± 120.03, 1420.85 ± 331.40, 137.20 ± 36.01) were significantly higher in the infection group compared to the control group (193.01 ± 31.82, 384.27 ± 363.93, 6.09 ± 10.85), respectively. Nisin treatment markedly reduced the Aβ42 (261.80 ± 52.50), total Tau (865.37 ± 304.93), and phosphorylated Tau (82.53 ± 15.77) deposition in the brain of the infection group.DiscussionNisin abrogation of brain microbiome dysbiosis induces beneficial effects on AD-like pathogenic changes and neuroinflammation, and thereby may serve as a potential therapeutic for periodontal-dysbiosis-related AD.

Periodontitis-related oral microbial dysbiosis is thought to contribute to adverse pregnancy outcomes (APOs), infertility, and female reproductive inflammation. Since probiotics can modulate periodontitis and oral microbiome dysbiosis, this study examined the effects of a probiotic bacteriocin, nisin, in modulating the reproductive microbiome and inflammation triggered by periodontitis. A total of 24 eight-week-old BALB/cByJ female mice were randomly divided into four treatment groups (control, infection, nisin, and infection+nisin group), with 6 mice per group. A polymicrobial (Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, Fusobacterium nucleatum) mouse model of periodontal disease was used to evaluate the effects of this disease on the female reproductive system, with a focus on the microbiome, local inflammation, and nisin's therapeutic potential in this context. Moreover, 16s RNA sequencing was used to evaluate the changes in the microbiome and RT-PCR was used to evaluate the changes in inflammatory cytokines. Periodontal pathogen DNA was detected in the reproductive organs, and in the heart and aorta at the end of the experimental period, and the DNA was especially elevated in the oral cavity in the infection group. Compared to the control groups, only P. gingivalis was significantly higher in the oral cavity and uterus of the infection groups, and T. forsythia and F. nucleatum were significantly higher in the oral cavity of the infection groups. The infection and nisin treatment group had significantly lower levels of P. gingivalis, T. forsythia, and F. nucleatum in the oral cavity compared with the infection group. Since periodontal pathogen DNA was also detected in the heart and aorta, this suggests potential circulatory system transmission. The polymicrobial infection generally decreased the microbiome diversity in the uterus, which was abrogated by nisin treatment. The polymicrobial infection groups, compared to the control groups, generally had lower Firmicutes and higher Bacteroidota in all the reproductive organs, with similar trends revealed in the heart. However, the nisin treatment group and the infection and nisin group, compared to the control or infection groups, generally had higher Proteobacteria and lower Firmicutes and Bacteroidota in the reproductive organs and the heart. Nisin treatment also altered the microbiome community structure in the reproductive tract to a new state that did not mirror the controls. Periodontal disease, compared to the controls, triggered an increase in inflammatory cytokines (IL-6, TNF-α) in the uterus and oral cavity, which was abrogated by nisin treatment. Polymicrobial periodontal disease alters the reproductive tract's microbial profile, microbiome, and inflammatory status. Nisin modulates the microbial profile and microbiome of the reproductive tract and mitigates the elevated uterine inflammatory cytokines triggered by periodontal disease. [ABSTRACT FROM AUTHOR]

Introduction: The rise of virtual simulation technology and dental simulators has created a new pedagogical approach for undergraduate medical education. The purpose of this study is to evaluate the effect of virtual simulation (VS) technology on improving the students' comprehensive abilities in periodontal probing teaching in pre‐practicum periodontology, such as increasing the accuracy of probing, tactile perception and performance on force control. Materials and Methods: Twenty students were randomly selected among the fourth‐year students and equally divided into VS technology teaching group (VS group) and traditional teaching group (TT group) by drawing half lots. One day later, students were required to probe the periodontal pathology model. The consistency rate between PD measurements and PD reference values, time consumption and final exam scores were recorded and statistically analysed using an unpaired Student's t test and p <.05 was considered statistical significance. Finally, questionnaires relating to teaching methods evaluation and the fidelity of the digital VS training system were distributed to students and teachers. Results: VS group had a significantly higher consistency rate (72.976 ± 6.811%) than TT group (64.107 ± 4.988%, p =.004). To specify, the difference of consistency rates between the two groups in posterior teeth was larger than anterior teeth. Similarly, a larger difference was also found in proximal surfaces compared with buccal‐lingual surfaces. As the pocket depth increased, the difference between the two groups increased too. These results indicated that VS is more efficient in complicated parts of periodontal probing teaching. In addition, students in VS group spent less time and gained a higher score than TT group (p <.05). The overall satisfaction rating in VS group was significantly higher than TT group. Lastly, teachers gave significant lower scores than students concerning the fidelity of VS system. Conclusion: Although there are much to improve, VS technology has obvious advantages in periodontal probing teaching in pre‐practicum periodontology. [ABSTRACT FROM AUTHOR]

Cognitive decline has been linked to periodontitis through an undetermined pathophysiological mechanism. This study aimed to explore the mechanism underlying periodontitis-related cognitive decline and identify therapeutic strategies for this condition. Using single-nucleus RNA sequencing we found that changes in astrocyte number, gene expression, and cell‒cell communication were associated with cognitive decline in mice with periodontitis. In addition, activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome was observed to decrease the phagocytic capability of macrophages and reprogram macrophages to a more proinflammatory state in the gingiva, thus aggravating periodontitis. To further investigate this finding, lipid-based nanoparticles carrying NLRP3 siRNA (NP siNLRP3 ) were used to inhibit overactivation of the NLRP3 inflammasome in gingival macrophages, restoring the oral microbiome and reducing periodontal inflammation. Furthermore, gingival injection of NP siNLRP3 reduced the number of Serpina3n high astrocytes in the hippocampus and prevented cognitive decline. This study provides a functional basis for the mechanism by which the destruction of periodontal tissues can worsen cognitive decline and identifies nanoparticle-mediated restoration of gingival macrophage function as a novel treatment for periodontitis-related cognitive decline., Competing Interests: The authors declare no competing interests., (© 2023 The Author(s).)