Adriana Miranda de Oliveira

Inflammatory Bowel Disease (IBD) is a multifactorial disorder characterized by chronic intestinal inflammation. Focusing on a single aspect of its pathogenesis is insufficient to capture the complexity of the disease. In this context, systemic inter‐organ communication, particularly the periodontitis‐IBD axis mediated by host immune cells and commensal microbiota, has recently emerged as an area of increasing importance in IBD research. This review aims to provide an integrative overview of gut seeding of potentially harmful oral bacteria (oral pathobionts) in IBD and its mechanistic insights along with the oral‐gut relationship in the context of IBD pathology. We also discuss potential factors that facilitate the gut seeding of oral pathobionts, a pivotal event underlying the oral‐gut axis. Elucidating these complex immune‐microbial dynamics across distant mucosal sites will deepen our understanding of the shared pathophysiology of oral and intestinal disorders and inform the development of novel therapeutic interventions.

Aim: To characterise periodontal and faecal microbiomes of individuals with periodontal health (PH) and diseases, and evaluate associations with periodontal, sociodemographic, anthropometric, nutritional and lifestyle factors. Materials and Methods: Dental biofilm and faecal samples from individuals ( n = 24/group) with PH, gingivitis (GG) and periodontitis (PE) were sequenced (16S rRNA). Anthropometric data and questionnaires on demographics, lifestyle, diet and intestinal habits were collected. Data were statistically analysed ( p < 0.05). Results: GG and PE groups showed higher age, BMI, waist/abdominal circumferences and trans‐fat intake and lower selenium and vitamin E intake compared to PH. Individuals with PE had higher hip circumference and lower income, education and intake of iron as well as vitamins A and B9. PE microbiomes (oral and faecal) showed distinct compositions, with the highest number of unique oral species. Faecal richness was lower in PE and GG compared to PH. Specific microbial taxa correlated with periodontal status and host factors. Conclusion: Periodontal and faecal microbiomes vary across periodontal conditions. Discriminant analysis classified 77% of individuals by periodontal status, with key markers for PE including older age, poor dietary quality and distinct microbial oral and faecal signatures. These findings highlight the role of clinical, dietary and microbial factors in periodontal disease profiling.

In the last decades, groundbreaking research on the human microbiome has changed our reductionist conception of the etiology and pathogenesis of several chronic diseases. As a result, we have come to appreciate the significance of a balanced microbiome in maintaining human health. In this context, the upper and lower gastrointestinal tracts (GITs) comprise the most abundant and diverse microbiotas of the human body. In addition to its diversity, functional redundancy, and temporal stability, a healthy GIT microbiome is characterized by its body site specificity. In fact, current evidence has indicated that the translocation of oral species to the gut environment through the oral–gut axis is increased in an array of illnesses, including chronic inflammatory and metabolic diseases, neurological disorders, and cancer. Oral pathogens have also been shown to promote gut dysbiosis and systemic inflammation in animal models. Yet, some level of overlapping between oral and gut microbiomes may occur without disruption of these microbial communities and loss of site specificity. The uniqueness of each host–microbiome entity may hinder our ability to define a “universal” normal GIT microbiome. Despite that, this chapter summarizes the predominant health-related taxa along the human GIT, as well as their role in the physiology and immunity of the digestive system. Some mechanisms that may lead to disturbances and relevant shifts in the oral and gut microbiomes of major inflammatory chronic diseases are also pointed out. Lastly, oral–fecal microbial signatures are presented as potential biomarkers for several oral and systemic disorders. The recognition of such symbiotic/dysbiotic microbial profiles may provide insights into the development of more accurate early diagnosis and therapeutic ecological approaches to restore the balance of the GIT microbiome.

Objective: To evaluate the adjunctive use of the probiotic Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) to conventional therapy on clinical and microbiological parameters in patients with generalized gingivitis. Methods: Sixty systemically healthy individuals with untreated generalized gingivitis were submitted to periodontal therapy and allocated to receive Placebo (n = 30) or Probiotic (n = 30) lozenges, twice a day for 8 weeks. Bleeding on Marginal Probing (BOMP) was evaluated at baseline, after 2 and 8 weeks. Supra and subgingival biofilm were obtained at baseline and 8 weeks post-therapy for analyses by 16S rRNA gene sequencing. Differences between therapeutic groups were analyzed by non-parametric tests (ppBergeyella and Corynebacterium were significantly associated with a greater reduction in bleeding in the Placebo group and with less reduction in bleeding in the Probiotic group, respectively. At species level, Schaalia spp., Streptococcus gordonii, and Leptotrichia wadei increased in Placebo and decreased in the Probiotic group after treatment. Granulicatella adiacens decreased significantly after the probiotic therapy, while Saccharibacteria (TM7) spp., Solobacterium moorei, and Catonella morbi increased significantly. In the Placebo group, Bergeyella sp. HMT-322 was associated with a greater percentage of reduction in bleeding. In both groups, Actinomyces species were related to less reduction in bleeding. Conclusion: The adjuvant use of B. lactis HN019 alongside conventional therapy enhanced the reduction in BOMP and promoted greater changes in the microbiological profile of patients with generalized gingivitis. Trial registration: The study was registered at Brazilian Clinical Trials Registry (ReBEC; protocol number: RBR-59v2yb).

Aim: Evidence suggests that translocation of oral pathogens through the oral–gut axis may induce intestinal dysbiosis. This study aimed to evaluate the impact of a highly leukotoxic Aggregatibacter actinomycetemcomitans (Aa) strain on the gut microbiota, intestinal mucosal integrity and immune system in healthy mice.Methods: Eight‐week‐old male C57BL6 mice were divided into control (n = 16) and JP2 groups (n = 19), which received intragastric gavage with PBS and with a suspension of Aa JP2 (HK921), respectively, twice a week for 4 weeks. Colonic lamina propria, fecal material, serum, gingival tissues, and mandibles were obtained for analyses of leukocyte populations, inflammatory mediators, mucosal integrity, alveolar bone loss, and gut microbiota. Differences between groups for these parameters were examined by non‐parametric tests.Results: The gut microbial richness and the number of colonic macrophages, neutrophils, and monocytes were significantly lower in Aa JP2‐infected mice than in controls (p < .05). In contrast, infected animals showed higher abundance of Clostridiaceae, Lactobacillus taiwanensis, Helicobacter rodentium, higher levels of IL‐6 expression in colonic tissues, and higher splenic MPO activity than controls (p < .05). No differences in tight junction expression, serum endotoxin levels, and colonic inflammatory cytokines were observed between groups. Infected animals presented also slightly more alveolar bone loss and gingival IL‐6 levels than controls (p < .05).Conclusion: Based on this model, intragastric administration of Aa JP2 is associated with changes in the gut ecosystem of healthy hosts, characterized by less live/recruited myeloid cells, enrichment of the gut microbiota with pathobionts and decrease in commensals. Negligible levels of colonic pro‐inflammatory cytokines, and no signs of mucosal barrier disruption were related to these changes.

The aim of this study was to evaluate the prevalence of Enterococcus species in the mouth of adults with periodontal health and periodontitis. A systematic search was made in databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. The search for articles was conducted in Medline/PubMed, Latin American and Caribbean Health Sciences Literature Database (LILACS), Cochrane Library, Scopus, Embase, Web of Science databases and in the System of Information on Grey Literature in Europe (SINGLE) and included articles published in English up to April 25th, 2021. Observational studies in humans with and without periodontitis were evaluated to identify the prevalence of Enterococcus species. Articles that met the inclusion criteria were analyzed and classified to determine the quality rating in good, fair, and poor. A new detailed checklist for quality assessment was developed based on the information required for applicable data extraction in reviews. The study design, sample size, demographic data, periodontal clinical parameters, microbial analysis method, biological sample, prevalence of Enterococcus spp., and correlations with periodontal clinical parameters were assessed. After screening and full-text reading, 8 articles met the inclusion criteria. All selected studies showed a significantly higher prevalence of Enterococcus spp. in patients with periodontitis compared with periodontally healthy patients. Thus, the present systematic review suggests that the prevalence of Enterococcus faecalis in the mouth of periodontitis individuals is higher than that of periodontally healthy individuals.

Objective: This investigation explored oral‐gut microbial signatures with potential to distinguish among periodontal conditions.Background Data: The interplay between the oral and gut microbiomes may be a critical pathway linking periodontal diseases and systemic inflammatory disorders. The mechanisms by which oral microorganisms translocate to the gut and cause microbial dysbiosis, favoring an inflammatory state, are still unknown. As a first approach, characterization of oral‐gut microbial profiles associated with periodontal health and diseases can provide insights on such mechanisms of etiology and pathogenesis.Methods: Fecal and saliva samples from individuals with periodontal health (PH, 8), gingivitis (GG, 17), and periodontitis (PD, 24) were analyzed for their microbial composition by 16S rRNA gene sequencing. Microbial taxa were compared and correlated to periodontal parameters. Multivariate discriminant analysis (MDA) was carried out to identify profiles related to health and disease.Results: Few significant differences in oral‐gut taxa were detected among clinical groups, although increase in fecal Fusobacterium nucleatum ss vincentii and salivary Aggregatibacter actinomycetemcomitans, Parvimonas micra, and Fretibacterium sp. HMT358 were strongly correlated with deep pockets and inflammation (p < .01). Over 50% of the fecal microbiota comprised microorganisms shared between oral and gut sites, whereas oral taxa were detected in approximately 9%, particularly enriched in GG fecal samples (p = .04). Trends for lower fecal richness and higher salivary diversity in PD compared to PH were observed. MDA was able to classify correctly 82% of the patients into the clinical groups. Main classifiers of periodontitis were high BMI, older age, and enrichment of oral‐fecal Leptotrichia sp. HMT4, Peptostreptococcus stomatis, Dialister invisus, and a novel Lautropia sp. HMTC89‐like organism.Conclusion: Within the limitations of an exploratory investigation, specific profiles of oral‐gut taxa, including known and potential novel organisms, combined with social‐demographic features were able to discriminate individuals with periodontal diseases in this study population.

Background: The oral‐gut axis may be a route linking periodontal and systemic diseases. Probiotics could be an alternative for the treatment of microbial dysbiotic conditions, including periodontitis. This randomized placebo‐controlled clinical trial evaluated the short‐term efficacy of systemic probiotics adjunctive to subgingival instrumentation (SI) in promoting a better restoration of the oral‐gut microbiotas and greater periodontal clinical outcome.Methods: Systemically healthy adults with untreated periodontitis were recruited from a Dental School setting and allocated to receive SI plus placebo (n = 24) or probiotics (n = 24), one capsule/day for 30 days. Subgingival biofilm and stool were obtained at baseline and 2‐months post‐therapy for microbiological analyses by checkerboard and 16S rRNA gene sequencing. Differences in all parameters between placebo (n = 23) and probiotics (n = 19) groups were assessed by non‐parametric tests.Results: Most subgingival species and α‐diversity decreased after therapies (P P P = 0.07). Strong correlations between oral and fecal species were found (P P P <0.05).Conclusion: Systemic probiotics combined with SI did not provide short‐term additional clinical or microbiological benefits in the treatment of periodontitis; however, response to therapies seemed to correlate with distinct oral‐gut microbial profiles.