Dysbiosis of salivary microbiota in inflammatory bowel disease and its association with oral immunological biomarkers

Characterization of the salivary microbiome of adults with inflammatory bowel disease

Background

Perturbations of the gut microbiota in patients with inflammatory bowel disease (IBD) have been extensively characterised, but changes to the oral microbiome remain understudied. This study aimed to evaluate the oral microbiome of adults with IBD and of matched controls.

Methods

Saliva samples and data were obtained from a Canadian population cohort (n = 320). The salivary microbiome was characterised using 16S rRNA gene sequencing and examined for differences between control participants and those with IBD, as well as disease subcategories (Crohn's Disease and Ulcerative Colitis).

Results

Alpha diversity was significantly lower in participants with IBD than controls in unadjusted models and many remained significant after adjusting for covariates. Significant differences in some beta diversity metrics between participants with IBD and controls were found, although these did not remain significant when adjusted for covariates. Ten genera were significantly differentially abundant between cases and controls. Veillonella and Streptococcus were both increased in abundance in IBD cases vs controls (25% vs 22% and 14% vs 12%, respectively).

Conclusion

These results showcase changes in oral microbial diversity and composition in those living with IBD and highlight the potential of using the salivary microbiome as a biomarker for screening or monitoring IBD.

Natural and induced immune responses in oral cavity and saliva

This review comprehensively explores the intricate immune responses within the oral cavity, emphasizing the pivotal role of saliva in maintaining both oral and systemic health. Saliva, a complex biofluid, functions as a dynamic barrier against pathogens, housing diverse cellular components including epithelial cells, neutrophils, monocytes, dendritic cells, and lymphocytes, which collectively contribute to robust innate and adaptive immune responses. It acts as a physical and immunological barrier, providing the first line of defense against pathogens. The multifaceted protective mechanisms of salivary proteins, cytokines, and immunoglobulins, particularly secretory IgA (SIgA), are elucidated. We explore the natural and induced immune responses in saliva, focusing on its cellular and molecular composition. In addition to saliva, we highlight the significance of a serum-like fluid, the gingival crevicular fluid (GCF), in periodontal health and disease, and its potential as a diagnostic tool. Additionally, the review delves into the impact of diseases such as periodontitis, oral cancer, type 2 diabetes, and lupus on salivary immune responses, highlighting the potential of saliva as a non-invasive diagnostic tool for both oral and systemic conditions. We describe how oral tissue and the biofluid responds to diseases, including considerations to periodontal tissue health and in disease periodontitis. By examining the interplay between oral and systemic health through the oral-systemic axis, this review underscores the significance of salivary immune mechanisms in overall well-being and disease pathogenesis, emphasizing the importance of salivary mechanisms across the body.

Alteration of salivary Streptococcus is associated with statin therapy in older adults: a cohort study

Background

Salivary microbiome alterations are associated with chronic diseases, such as cardiovascular disease, diabetes, and dementia. These chronic diseases often coexist in older adults, leading to polypharmacy. This situation complicates the relationship between systemic diseases and salivary microbiome dysbiosis. Previous studies have demonstrated the association of the human gut microbiome with common prescription drug use, including polypharmacy. However, a comprehensive analysis of the salivary microbiome and prescription drugs is yet to be conducted in older adults. Therefore, in this study, we performed a multivariate analysis to investigate the relationship between salivary microbiomes and host variables, including prescribed drugs, cognitive function, and oral health, in Japanese older adults with different disease backgrounds.

Methods

We enrolled non-hospitalised 82 older adults aged ≥70 years from a Japanese village community, and collected metadata, including age, sex, body mass index, cognitive function, oral health, alcohol consumption, smoking, and common prescription drug information. We performed multivariate analyses and functional predictions on the salivary microbiome based on 16S ribosomal RNA gene amplicon sequencing, including the metadata as potential confounders.

Results

We observed a relationship between the human salivary microbiome and prescribed drug use in Japanese older adults with a heterogeneous background of comorbidities. The effects of several prescribed drugs, such as statins, proton pump inhibitors, and transporter/symporter inhibitors, on the salivary microbiome diversity were more prominent than those of host variables, including age, sex, and oral health. Notably, statin use was strongly correlated with a decrease in the Streptococcus abundance. Furthermore, statin intensity and obesity may be associated with altering the salivary microbiome, including functional predictions for vitamin biosynthesis and purine nucleotide degradation pathways in statin users.

Conclusion

Our multivariate analysis, adjusted for prescribed drug use and non-use, revealed the drug-specific alteration of salivary microbiome composition in Japanese older adults with comorbidities. To our knowledge, this study is the first to described the association of common prescription drug use with salivary microbiome alterations in older adults. Our findings indicated that prescribed drug use is a key factor in understanding the link between salivary microbiome changes and systemic diseases in older adults.

The Bidirectional Effects of Periodontal Disease and Oral Dysbiosis on Gut Inflammation in Inflammatory Bowel Disease

BACKGROUND AND AIMS

Inflammatory bowel disease (IBD) flares can lead to excessive morbidity and mortality. This study aimed to determine whether oral dysbiosis/periodontal disease (PD) is common in IBD and is associated with disease activity in IBD.

METHODS

This single-center, prospective, cross-sectional, proof-of-concept, and observational study assessed the frequency of periodontal inflammatory disease and interrogated oral and stool microbiota using 16S rRNA gene amplicon sequencing of active-IBD (aIBD), inactive-IBD (iIBD), and healthy controls (HC). Questionnaires assessed diet, alcohol usage, oral hygiene behavior, and disease activity. A subset of participants underwent comprehensive dental examinations to evaluate PD.

RESULTS

Periodontal disease was severer in aIBD subjects than in HC, as aIBD had poorer quality diets (lower Mediterranean diet scores) than iIBD and HC. Significant differences in microbial community structure were observed in unstimulated saliva, stimulated saliva, gingiva, and stool samples, primarily between aIBD and HC. Saliva from aIBD had higher relative abundances of putative oral pathobionts from the genera Streptococcus, Granulicatella, Rothia, and Actinomyces relative to HC, despite similar oral hygiene behaviors between groups.

CONCLUSIONS

Our study suggests that patients with aIBD have severer periodontal disorders and higher relative abundances of putative 'pro-inflammatory' microbiota in their oral cavity, despite normal oral hygiene behaviors. Our data are consistent with the potential presence of an oral-gut inflammatory axis that could trigger IBD flare-ups in at-risk patients. Routine dental health assessments in all IBD patients should be encouraged as part of the health maintenance of IBD and as a potential strategy to decrease the risk of IBD flares.

A systematic review and network meta-analysis of the association between periodontitis and inflammatory bowel diseases

OBJECTIVES

Several earlier studies have shown that IBD (including its two subtypes, ulcerative colitis (UC) and Crohn's disease (CD)) increases the risk of periodontal disease. This study aimed to evaluate the relevance among periodontitis and IBD subcategories.

METHODS

This study was conducted based on PRISMA guidelines. The Web of Science, PubMed, Google Scholar, and Scopus databases were searched up to February 2024 using pertinent keywords. Case series, review articles, and animal studies were excluded. The risk of bias in this research was evaluated through the Joanna Briggs Institute (JBI) criteria. The meta-analysis was conducted using R statistical software.

RESULTS

A total of 9134 patients within 13 studies after the screening process were evaluated. Our study has shown that periodontitis is significantly more prevalent among IBD patients (UC and CD). According to prior meta-analyses, PD morbidity was found to be significantly high among CD patients (OR: 4.30; 95% CI: 3.72-4.98; I2 = 0%). Similarly, UC elevated PD risk (OR: 4.55; 95% CI: 3.76-5.50; I2 = 0%). The risk of periodontitis was not significantly different between CD and UC patients (OR: 0.96; 95% CI: 0.65-1.43; I2 = 34%).

CONCLUSIONS

UC and CD patients were more likely to develop periodontitis, with low heterogeneity between studies, while the prevalence of periodontitis among UC and CD patients was not meaningfully different.

CLINICAL RELEVANCE

The higher risk of periodontitis in patients with IBD indicates the necessity of screening for periodontitis. Considering the various oral manifestations and poor quality of life associated with IBD, it is important to be aware of the symptoms of periodontitis.

Host Transcriptome and Microbial Variation in Relation to Visceral Hyperalgesia

BACKGROUND

Chronic visceral hypersensitivity is associated with an overstressed pain response to noxious stimuli (hyperalgesia). Microbiota are active modulators of host biology and are implicated in the etiology of visceral hypersensitivity.

OBJECTIVES

we studied the association between the circulating mRNA transcriptome, the intensity of induced visceral pain (IVP), and variation in the oral microbiome among participants with and without baseline visceral hypersensitivity.

METHODS

Transcriptomic profiles and microbial abundance were correlated with IVP intensity. Host mRNA and microbes associated with IVP were explored, linking variation in the microbiome to host RNA biology.

RESULTS

259 OTUs were found to be associated with IVP through correlation to differential expression of 471 genes in molecular pathways related to inflammation and neural mechanisms, including Rho and PI3K/AKT pathways. The bacterial families Lachnospiraceae, Prevotellaceae, and Veillonellaceae showed the highest degree of association. Oral microbial profiles with reduced diversity were characteristic of participants with visceral hypersensitivity.

CONCLUSIONS

Our results suggest that the oral microbiome may be involved in systemic immune and inflammatory effects and play a role in nervous system and stem cell pathways. The interactions between visceral hypersensitivity, differentially expressed molecular pathways, and microbiota described here provide a framework for further work exploring the relationship between host and microbiome.

Ex Vivo Analysis of the Effect of Endoscopic Premedications on the Microbiota Profile in Gastric Juice

Background and Aim

Dimethicone (GAS), lidocaine (XYL), and protease (PRO) are commonly used as premedications during esophagogastroduodenoscopy (EGD). However, the effects of these drugs on the gastric microbiota remain unexplored. Therefore, we aimed to investigate the effects of these premedications on gastric juice collected from patients undergoing EGD.

Methods

Gastric juice was endoscopically aspirated from six patients and divided into six aliquots for in vitro analysis. The samples were mixed with premedications in corresponding treatment sets: GAS, XYL, PRO, MIX (a mixture of GAS, XYL, and PRO), and control (CTL1 and 2; no medication treatment). After extraction of microbial DNA from the treated samples, the 16S rRNA amplicon sequence was analyzed to determine the microbiota profile in terms of (1) the amount of genomic DNA (gDNA), (2) α-diversity indices, Shannon index, number of observed operational taxonomic units (OTUs), and Chao1 index, (3) weighted and unweighted UniFrac distances, and (4) the relative abundance of phyla and genera.

Results

The total amount of extracted gDNA did not significantly differ between the six groups. The α-diversity indices did not significantly differ between treatment groups. Although GAS, PRO, and MIX differed significantly from the technical replicates in the weighted UniFrac distance (p = 0.03 all), no significant difference was observed in the unweighted UniFrac distance. However, significant differences were observed in the relative abundance of several bacterial microbiota at the phylum and genus levels.

Conclusions

Premedications affect the microbiota profile of specific phylum- and genus-level bacterial groups. Trial Registration: University Hospital Medical Information Network Clinical Trials Registry: UMIN-CTR 000040192 and UMIN-CTR 000051289.

Dental problems and oral microbiome alterations in ulcerative colitis

Ulcerative colitis is a chronic disease that has not well-established etiology. The role of microbial dysregulation in its pathogenesis has been recently highlighted. Overall, microbiome alterations concern the reduction of bacterial abundance and diversity, resulting in gut microbiome imbalance negatively affecting immunological aspects. There is a link between ulcerative colitis and the oral microbiome. The changes of oral microbiome are found at many levels, from gently dysbiotic composition to the presence of the main periodontal microbes. The analysis of oral microbiome can be a part of personalized medicine due to the fact that it is a potential biomarker. Patients with ulcerative colitis may manifest dental symptoms/problems, such as periodontitis (strongly related to the red-complex pathogens-Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, and bacteria belonging to the other complexes, such as Fusobacterium nucleatum and Aggregatibacter actinomycetecomitans), dental caries, oral ulcerations, leukoplakia, halitosis, and others. Notably, the DMFT (Decayed, Missing, Filled Teeth) index is higher in these patients compared to healthy subjects. According to some data, oral lichen planus (which is a disease with an immunological background) can also be observed in ulcerative colitis patients. It seems that deep understanding of ulcerative colitis in association with oral microbiome, immunology, and dental manifestations may be crucial to provide complex treatment from a dental point of view.

Alterations in the Tongue Coating Microbiome in Patients With Diarrhea-Predominant Irritable Bowel Syndrome: A Cross-Sectional Study

The gut microbiota plays a critical role in the occurrence and development of IBS-D, however, IBS-D-associated tongue coating microbiome dysbiosis has not yet been clearly defined. To address this, we analyzed the structure and composition of the tongue coating microbiome in 23 IBS-D patients and 12 healthy controls using 16S rRNA high-throughput sequencing analysis. The 16S rRNA sequencing results revealed that the overall observed OTUs of tongue coating microbiome in IBS-D patients exhibited a significant decrease compared with the healthy controls. Alpha diversity analysis showed that the diversity and community richness were significantly reduced in IBS-D patients, and PCoA revealed a distinct clustering of tongue coating microbiome between the IBS-D patients and healthy controls. Microbial comparisons at the genus level showed that the abundance of Veillonella, Prevotella in IBS-D patients was higher than those in healthy controls, while Streptococcus, Haemophilus, Granulicatella, and Rothia were significantly reduced compared with the healthy volunteers. Functional analysis results showed significant differences in 88 functional metabolic pathways between the IBS-D patients and the healthy controls, including fatty acid biosynthesis. These findings identified the structure, composition, functionality of tongue coating microbiome in IBS-D patients, and hold promise the potential for therapeutic targets during IBS-D management.

Study on the relationship between microbial composition within obstructive biliary stents and the severity of obstruction and duration of stent placement

Biliary stent occlusion is due, in part, to biofilm formation by bacteria. However, previous culture-based approaches may not have revealed all microorganisms on the surface. Twenty-seven patients underwent endoscopic retrograde biliary drainage for the removal or replacement of plastic biliary stents. We analyzed occlusion severity using image-analyses of a longitudinal section of the biliary stent and evaluated the microbial profile of sludge deposition inside the stents using 16S rRNA sequencing with a MiSeq Illumina platform. We then evaluated the association of microbial profiles with the duration of stent placement and stent occlusion severity. Actinobacteria and Synergistetes were much more abundant in occluded stents compared with non-occluded stents. An abundance of Bifidobacterium spp. and OTU00006 Bifidobacterium animalis (100%) correlated with stent occlusion severity (rho, 0.62; p<0.001; and 0.42; p = 0.03, respectively), and this relationship remained after adjusting for the duration of stent placement (p = 0.03 and 0.05, respectively). The genus Bifidobacterium and Bifidobacterium animalis were associated with the degree of occlusion in plastic biliary stents.

Salivary calprotectin and neutrophils in inflammatory bowel disease in relation to oral diseases

OBJECTIVE

Calprotectin is elevated in saliva from inflammatory bowel disease (IBD) patients, but it is also affected by oral disease. We assessed the salivary concentration of calprotectin in IBD patients, in relation to intestinal and oral diseases. Furthermore, we investigated the phenotype of salivary neutrophils from IBD patients, and their ability to secrete calprotectin.

MATERIALS AND METHODS

Thirty IBD patients and 26 controls were orally examined and sampled for stimulated saliva. Twenty-five IBD patients provided fresh fecal samples. Calprotectin concentrations in saliva and feces were determined by an enzyme-linked immunosorbent assay. Expression of CD11b, CD15, and CD16 on oral neutrophils was assessed by flow cytometry. Secretion of calprotectin was evaluated in cultured oral neutrophils.

RESULTS

Calprotectin was significantly elevated in saliva of IBD patients compared to controls, particularly in Crohn's disease, irrespective of caries or periodontitis. Salivary calprotectin did not correlate to fecal calprotectin. CD11b expression was significantly reduced in salivary neutrophils from IBD patients. Salivary neutrophils from IBD patients tended to secrete more calprotectin than controls.

CONCLUSIONS

Salivary calprotectin is elevated in IBD regardless of oral diseases. Furthermore, salivary neutrophils secrete calprotectin, and display lower CD11b expression in IBD.

Polypeptide of Inonotus hispidus extracts alleviates periodontitis through suppressing inflammatory bone loss

This study aimed to characterize and evaluate the effects of a novel polypeptide isolated from Inonotus hispidus (IH) against periodontitis. The polypeptides extracted and purified from the fruiting body of IH had a uniform molar mass, including 23 types of peptides. IH polypeptide (IHP) exerted antimicrobial activity against Porphyromonas gingivalis (P. gingivalis) by damaging the cell walls and membranes of microorganisms, disturbing energy metabolism, and regulating the expression of virulence factors. IHP significantly inhibited inflammation in lipopolysaccharides (LPS)-stimulated Raw264.7 cells evidenced by the regulation of inflammatory cytokine levels. In rats with ligature-induced periodontitis, IHP treatment ameliorated alveolar bone destruction and preserved the balance between oral flora and gut microbes. The interaction between oral and intestinal flora possibly affected the relevant metabolites. Proteomics combined with confirmation experiment revealed that the β-catenin/ nuclear factor-kappa B (NF-κB) signaling may be involved in IHP-mediated anti-periodontitis in rats, which helps reduce the secretion of pro-inflammatory factors and inhibit inflammatory osteoclastic response in the periodontal tissue. Additionally, IHP improved clinical parameters, including the plaque index (PLI), pocket depth (PD), bleeding on probing (BOP), and average probing depth in individuals with periodontitis. These findings augment the understanding of the potential role of IHP in treating periodontitis.

The oral-gut microbiome axis in health and disease

The human body hosts trillions of microorganisms throughout many diverse habitats with different physico-chemical characteristics. Among them, the oral cavity and the gut harbour some of the most dense and diverse microbial communities. Although these two sites are physiologically distinct, they are directly connected and can influence each other in several ways. For example, oral microorganisms can reach and colonize the gastrointestinal tract, particularly in the context of gut dysbiosis. However, the mechanisms of colonization and the role that the oral microbiome plays in causing or exacerbating diseases in other organs have not yet been fully elucidated. Here, we describe recent advances in our understanding of how the oral and intestinal microbiota interplay in relation to their impact on human health and disease.

Bidirectional associations between periodontitis and inflammatory bowel disease: A systematic review of longitudinal studies with meta-analysis and trial sequential analysis

The bidirectional associations between periodontitis and inflammatory bowel disease (IBD) with temporal directionality remain inconclusive. This study aims to evaluate the bidirectional associations between periodontitis and IBD through a systematic review and meta-analysis. Five databases (PubMed, Embase, Web of Science, Scopus and Cochrane Library) were systematically searched from inception to 27 February 2024. Two independent reviewers performed a review of the retrieved studies. Longitudinal studies, including cohort and nested case-control studies, were considered eligible for the study design. The pooled risk ratio (RR) and hazard ratio (HR) derived from the meta-analysis were used to assess whether periodontitis (or IBD) was a risk factor for IBD (or periodontitis). Trial sequential analysis (TSA) was performed to evaluate the reliability of the results. Four studies (n = 10 270 912) on the risk of IBD in patients with periodontitis and two (n = 33 420) on the risk of periodontitis in patients with IBD were included. The result suggested that periodontitis did not increase the risk of IBD (pooled RR = 1.04, 95% confidence interval [CI]: 0.99-1.09; p = .164; I-squared statistic [I2] = 27%). For subtypes of IBD, periodontitis was associated with the occurrence of ulcerative colitis (UC) (pooled RR = 1.12, 95% CI: 1.04-1.21; p = .003; I2 = 38%), but not with Crohn's disease (CD) (pooled RR = 0.98, 95% CI: 0.92-1.04; p = .475; I2 = 0%). Specifically, the risk of UC was higher among men (pooled HR = 1.11, 95% CI: 1.01-1.22; p = .025; I2 = 0%) and smokers (pooled HR = 1.23, 95% CI: 1.07-1.42; p = .004; I2 = 0%) with periodontitis than their counterparts without periodontitis. Patients with IBD may have a higher risk of developing periodontitis (pooled HR = 1.37, 95% CI: 1.26-1.49; p < .001; I2 = 18%); however, whether IBD subtypes increased the occurrence of periodontitis remained uncertain. The TSA results confirmed the reliability of the primary findings. Based on limited longitudinal evidence, patients with periodontitis do not exhibit an increased risk of developing IBD overall, but they are at increased risk of UC (not CD). On the contrary, patients with IBD have a higher risk of developing periodontitis over time. More high-quality longitudinal studies are needed to determine the effect of specific subtypes of IBD on periodontitis.

Salivary Immunoglobulin a Alterations in Health and Disease: A Bibliometric Analysis of Diagnostic Trends from 2009 to 2024

BACKGROUND/OBJECTIVES

Salivary immunoglobulin A (IgA) is a mediator of local immunity and host defence. Altered IgA levels may predispose to bacterial invasion of the mucosa in the gastrointestinal tract, including the oral cavity. Our study aimed to present the diagnostic trends related to salivary IgA in health and disease based on a bibliometric analysis of published papers between 2009 and 2024.

METHODS

By 14 September 2024, 1247 English original articles were found in the database Web of Science. We selected 838 records considering the diagnostic usefulness of IgA in human subjects. Based on bibliographic data, we created citation and keyword co-occurrence maps using VOSviewer 1.6.20.

RESULTS

Most articles belonged to the "Sport Sciences" category (n = 169), followed by the "Immunology" category (n = 93). The Brazilian researcher Alexandre Moreira from the University of Sao Paulo had the most published and most frequently cited papers. Most of the included articles came from the USA (n = 158), England (n = 105), Brazil (n = 95), and Japan (n = 95). The most cited article described research on IgA in response to SARS-CoV-2 infection (n = 690), but the subsequent two papers considered the role of salivary IgA in the dysbiosis of the intestinal microbiota in inflammatory bowel diseases (n = 272) and the formation of systemic immune responses from the gastrointestinal tract (n = 245).

CONCLUSIONS

Salivary IgA is a widely evaluated diagnostic marker in both patients and healthy individuals. Numerous reports have identified its changes as a result of physical exertion in various groups of athletes, during infections (including SARS-CoV-2) and in the course of local diseases (e.g., periodontal disease) or systemic diseases (e.g., inflammatory bowel disease).

Changes in Immunoglobulins G and A in the Saliva and Serum of Horses with Equine Gastric Ulcer Syndrome (EGUS) and Their Relationship with Other Immune and Redox Status Biomarkers

Equine Gastric Ulcer Syndrome (EGUS) is a widespread disease with a very high prevalence and importance in horses. It includes two conditions: Equine squamous gastric disease (ESGD), linked to acid disturbances, and Equine Glandular Gastric Disease (EGGD), associated with inflammation and immune system issues. In saliva, increased levels of immunological markers have been observed in this disease, indicating immune system involvement. In addition, changes in biomarkers of oxidative stress have been described. In horses, IgG and IgA are proteins that appear in saliva and serum and are considered to be the major proteins in specific immunity; however, their levels in horses with EGUS have not been previously studied. This report aims to evaluate IgG and IgA concentrations in the saliva and serum of horses with EGUS, measured by automated assays, and compare them with other biomarkers of the immune and oxidative stress system. This work validated the IgG and IgA assays in saliva and showed that IgA significantly increased in the saliva of horses with EGUS. When the correlation between IgG and IgA and other biomarkers of immune system issues and oxidative stress such as ADA, S100 A8-A9 (calprotectin), S100 A12 (calgranulin), uric acid, FRAS, and AOPP was studied, IgA in saliva showed a significant moderate correlation with adenosine deaminase, indicating its possible involvement in the immune reaction occurring in EGUS.

Balancing the Oral-Gut-Brain Axis with Diet

Background: The oral microbiota is the second largest microbial community in humans. It contributes considerably to microbial diversity and health effects, much like the gut microbiota. Despite physical and chemical barriers separating the oral cavity from the gastrointestinal tract, bidirectional microbial transmission occurs between the two regions, influencing overall host health. Method: This review explores the intricate interplay of the oral-gut-brain axis, highlighting the pivotal role of the oral microbiota in systemic health and ageing, and how it can be influenced by diet. Results: Recent research suggests a relationship between oral diseases, such as periodontitis, and gastrointestinal problems, highlighting the broader significance of the oral-gut axis in systemic diseases, as well as the oral-gut-brain axis in neurological disorders and mental health. Diet influences microbial diversity in the oral cavity and the gut. While certain diets/dietary components improve both gut and oral health, others, such as fermentable carbohydrates, can promote oral pathogens while boosting gut health. Conclusions: Understanding these dynamics is key for promoting a healthy oral-gut-brain axis through dietary interventions that support microbial diversity and mitigate age-related health risks.

Oral microbiome diversity shapes the association between sleep duration and depression

Background

Emerging research suggests the relationship between the oral microbiome and sleep duration with depression, however, the precise mechanisms by which oral microbial diversity influences the sleep-depression nexus remain to be elucidated.

Methods

We analyzed data from 4,692 participants in the National Health and Nutrition Examination Survey (NHANES), incorporating key demographic variables, oral microbiome diversity metrics, sleep duration, and depression assessment variables. Classical multidimensional scaling facilitated dimensionality reduction, while unsupervised clustering divided participants into groups based on β-diversity dissimilarity matrices. We examined the moderating effects of oral microbiome diversity on the sleep-depression relationship by incorporating interaction terms sleep-oral microbiome diversity into multiple linear regression models.

Results

Our analysis revealed a U-shaped relationship between sleep duration and depression. Specifically, α-diversity was a significant moderator, with reduced diversity linked to an increased depression risk in participants with insufficient sleep. Regarding β-diversity, using both Bray-Curtis and UniFrac distance measures, Cluster 2 exhibited the strongest associations in sleep-deprived individuals (Bray-Curtis: β = 1.02, p < 0.001; Weighted UniFrac: β = 0.91, p < 0.001). In contrast, Cluster 1 displayed notable effects in individuals with excessive sleep (Bray-Curtis: β = 0.63, p = 0.008). Additionally, Cluster 3 was prominently associated with depression in sleep-deprived participants using unweighted UniFrac distance (β = 0.93, p < 0.001), and Cluster 2 was significant among those with excessive sleep across both unweighted (β = 0.80, p = 0.0004) and weighted UniFrac distances (β = 0.60, p = 0.001).

Conclusion

This study highlights the crucial role of oral microbiome diversity in moderating the U-shaped relationship between sleep duration and depression risk.

The influence of the oral microbiota in full-term pregnant women on immune regulation during pregnancy

BACKGROUND

This study aims to conduct a preliminary exploration of the correlation between the oral microbiota of full-term pregnant women and both local placental immunity and the systemic immune system of the mother.

METHODS

A total of 26 pregnant women participated in this study, with samples collected from oral swabs, placental tissue, and peripheral venous blood. High-throughput sequencing was used to examine the oral microbial community. Flow cytometry was employed to assess immune cells in placental tissue and peripheral venous blood. ELISA and Luminex liquid bead chip technology were utilized to detect cytokines in both placental tissue and peripheral venous blood.

RESULTS

In placental tissue, The oral microbial community is primarily negatively correlated with placental CD3+CD4+CD8+T cells and positively correlated with placental IL-5. In the peripheral blood, The oral microbial community is primarily positively correlated with maternal systemic immune parameters, including CD3+CD4+ T cells and the CD4+/CD8+ ratio, as well as positively correlated with peripheral IL-18.

CONCLUSIONS

The oral microbiota of full-term pregnant women participates in the regulatory function of the maternal immune system. Meanwhile, the oral microbial community may also be an important factor mediating local immune regulation in the placenta.

Oral Anti-Inflammatory and Symbiotic Effects of Fermented Lingonberry Juice-Potential Benefits in IBD

Microbial dysbiosis may manifest as inflammation both orally and in the gastrointestinal tract. Altered oral and gut microbiota composition and decreased diversity have been shown in inflammatory bowel disease (IBD) and periodontal disease (PD). Recent studies have verified transmission of oral opportunistic microbes to the gut. Prebiotics, probiotics, or dietary interventions are suggested to alleviate IBD symptoms in addition to medicinal treatment. Lingonberries contain multiple bioactive molecules, phenolics, which have a broad spectrum of effects, including antimicrobial, anti-inflammatory, antioxidant, anti-proteolytic, and anti-cancer properties. An all-natural product, fermented lingonberry juice (FLJ), is discussed as a potential natural anti-inflammatory substance. FLJ has been shown in clinical human trials to promote the growth of oral lactobacilli, and inhibit growth of the opportunistic oral pathogens Candida, Streptococcus mutans, and periodontopathogens, and decrease inflammation, oral destructive proteolysis (aMMP-8), and dental microbial plaque load. Lactobacilli are probiotic and considered also beneficial for gut health. Considering the positive outcome of these oral studies and the fact that FLJ may be swallowed safely, it might be beneficial also for the gut mucosa by balancing the microbiota and reducing proteolytic inflammation.

Oral Health and "Modern" Digestive Diseases: Pathophysiologic and Etiologic Factors

In the contemporary era of medicine, exploring the complexity of the human body and its intricate interactions has become a central concern for health researchers. The main purpose of this article is to summarize the current understanding of relevant pathophysiological factors such as chronic inflammation, dysbiosis (microbial imbalance), and metabolic disorders, as well as etiological factors including dietary habits, lifestyle choices, obesity, metabolic syndrome, and genetic predispositions, as well as to emphasize potential avenues for upcoming studies and their medical significance. Additionally, this article aims to assess the potential impact of integrated treatment approaches on patient outcomes, emphasizing the need for interdisciplinary collaboration between gastroenterologists, dentists, and other healthcare professionals to develop comprehensive care plans that address both oral and digestive health issues simultaneously. Among the branches with a significant impact on general well-being are oral cavity health and digestive diseases, which have been the subject of intensive research in recent decades. In this context, analysis of the current state of knowledge on oral cavity disorders in relation to "modern" digestive diseases such as non-alcoholic fatty liver disease (NAFLD), small intestinal bacterial overgrowth (SIBO), inflammatory bowel disease (IBD), and irritable bowel syndrome (IBS) becomes essential for a deeper understanding of the interconnections between oral and digestive health. The temporal overlap or succession, whether preceding or following, of oral manifestations and digestive disorders should be taken seriously by both gastroenterologists and dentists to facilitate early diagnosis and explain to patients the correlation between these two body systems. In summary, this article underscores the importance of understanding the intricate relationship between oral and digestive health, advocating for interdisciplinary approaches to improve patient outcomes and guide future research.

Unravelling the Oral-Gut Axis: Interconnection Between Periodontitis and Inflammatory Bowel Disease, Current Challenges, and Future Perspective

As the opposite ends of the orodigestive tract, the oral cavity and the intestine share anatomical, microbial, and immunological ties that have bidirectional health implications. A growing body of evidence suggests an interconnection between oral pathologies and inflammatory bowel disease [IBD], implying a shift from the traditional concept of independent diseases to a complex, reciprocal cycle. This review outlines the evidence supporting an 'oral-gut' axis, marked by a higher prevalence of periodontitis and other oral conditions in IBD patients and vice versa. We present an in-depth examination of the interconnection between oral pathologies and IBD, highlighting the shared microbiological and immunological pathways, and proposing a 'multi-hit' hypothesis in the pathogenesis of periodontitis-mediated intestinal inflammation. Furthermore, the review underscores the critical need for a collaborative approach between dentists and gastroenterologists to provide holistic oral-systemic healthcare.

Association between the oral microbiome and brain resting state connectivity in schizophrenia

Recent microbiome-brain axis findings have shown evidence of the modulation of microbiome community as an environmental mediator in brain function and psychiatric illness. This work is focused on the role of the microbiome in understanding a rarely investigated environmental involvement in schizophrenia (SZ), especially in relation to brain circuit dysfunction. We leveraged high throughput microbial 16s rRNA sequencing and functional neuroimaging techniques to enable the delineation of microbiome-brain network links in SZ. N = 213 SZ and healthy control subjects were assessed for the oral microbiome. Among them, 139 subjects were scanned by resting-state functional magnetic resonance imaging (rsfMRI) to derive brain functional connectivity. We found a significant microbiome compositional shift in SZ beta diversity (weighted UniFrac distance, p = 6 × 10-3; Bray-Curtis distance p = 0.021). Fourteen microbial species involving pro-inflammatory and neurotransmitter signaling and H2S production, showed significant abundance alterations in SZ. Multivariate analysis revealed one pair of microbial and functional connectivity components showing a significant correlation of 0.46. Thirty five percent of microbial species and 87.8 % of brain functional network connectivity from each component also showed significant differences between SZ and healthy controls with strong performance in classifying SZ from healthy controls, with an area under curve (AUC) = 0.84 and 0.87, respectively. The results suggest a potential link between oral microbiome dysbiosis and brain functional connectivity alteration in relation to SZ, possibly through immunological and neurotransmitter signaling pathways and the hypothalamic-pituitary-adrenal axis, supporting for future work in characterizing the role of oral microbiome in mediating effects on SZ brain functional activity.

Isolation and identification of hoylesella marshii causing pleural infection: a case report

BACKGROUND

Hoylesella marshii can be isolated from human oral cavities affected by dental pulp and periodontal infections, as well as from the dental plaque of healthy individuals, making it a common bacterium within the oral microbiota. However, its role in causing pleural infections in humans is rare.

CASE PRESENTATION

A case of purulent pleural effusion occurred shortly after discharge in an elderly patient who had undergone surgery for gastric cancer. The infection was identified as being caused by an obligate anaerobe through laboratory culture, and was further identified as Hoylesella marshii causing pleural infection through 16 S rRNA gene sequence analysis. Susceptibility testing guided precise treatment with cefoperazone-sulbactam and metronidazole. The patient's clinical symptoms improved rapidly, laboratory test indicators gradually returned to normal, and the patient ultimately recovered.

CONCLUSION

Hoylesella marshii can cause pleural infections in humans. Clinical microbiology laboratories should pay special attention to the cultivation of obligate anaerobes when routine aerobic cultures do not show bacterial growth but bacteria are visible on smear staining, and when conventional identification methods fail to identify the bacterium, analysis based on the highly conserved 16 S rRNA gene sequence can accurately and specifically identify the bacterium, guiding clinicians in formulating precise anti-infection strategies.

A pilot study on the characterization and correlation of oropharyngeal and intestinal microbiota in children with type 1 diabetes mellitus

Background

Type 1 Diabetes Mellitus (T1DM) is one of the most common endocrine disorders of childhood and adolescence, showing a rapidly increasing prevalence worldwide. A study indicated that the composition of the oropharyngeal and gut microbiota changed in T1DM. However, no studies have yet associated the changes between the microbiomes of the oropharyngeal and intestinal sites, nor between the flora and clinical indicators. In this study, we examined the composition and characteristics of oropharyngeal and intestinal flora in patients with T1DM in compared to healthy children. We identified correlations between oropharyngeal and intestinal flora and evaluated their association with clinical laboratory tests in patients with T1DM.

Methods

The oropharyngeal and fecal samples from 13 T1DM and 20 healthy children were analyzed by high-throughput sequencing of the V3-V4 region of 16S rRNA. The associations between microbes and microorganisms in oropharyngeal and fecal ecological niches, as well as the correlation between these and clinical indicators were further analyzed.

Results

It was revealed that T1DM children had distinct microbiological characteristics, and the dominant oropharyngeal microbiota genus included Streptococcus, Prevotella, Leptotrichia, and Neisseria; that of intestinal microbiota included Blautia, Fusicatenibacter, Bacteroides, and Eubacterium_hallii_group. Furthermore, oropharyngeal Staphylococcus was significantly positively correlated with intestinal norank_f__Ruminococcaceae and Ruminococcus_torques_group in TIDM children. Moreover, in these children, differential genes in oropharyngeal and intestinal samples were enriched in metabolic pathways such as amino acid generation, fatty acid metabolism, and nucleotide sugar biosynthesis. Additionally, correlation analysis between the oropharyngeal/intestinal microbiome with laboratory tests showed significant correlations between several bacterial taxa in the oropharynx and intestines and glycated hemoglobin and C-peptide.

Conclusion

Unique microbial characteristics were found in the oropharynx and intestine in children with T1DM compared to healthy children. Positive correlations were found between changes in the relative abundance of oropharyngeal and gut microbiota in children with T1DM. Associations between the oropharyngeal/intestinal microbiota and laboratory investigations in children with T1DM suggest that the composition of the oropharyngeal and intestinal flora in children with T1DM may have some impact on glycemic control.

Key periodontal pathogens may mediate potential pathogenic relationships between periodontitis and crohn's disease

BACKGROUND

Crohn's disease (CD)-associated periodontitis is common. However, the role of periodontal pathogens in the Coexistence of CD and periodontal disease remains unclear.

METHODS

To investigate the potential relationship mediated by periodontal pathogens between periodontitis and CD, we collected salivary samples from healthy participants (H group, n = 12), patients with CD (Ch group, n = 10), patients with periodontitis (Ps group, n = 12), and patients with Coexistence of CD and periodontal disease (Cp group, n = 12) and analyzed them by 16 S rRNA sequencing.

RESULTS

Patients with Coexistence of CD and periodontal disease had increased levels of Fusobacterium, Actinomyces, Leptotrichia, and Prevotella, which correlated with the severity of periodontitis. Conversely, the levels of Streptococcus, Neisseria, Haemophilus, and Gemella, which decreased in Coexistence of CD and periodontal disease, were negatively correlated with the severity of periodontitis. To further investigate the role of periodontal pathogens in CD development, representative periodontal pathogens causing periodontitis, Porphyromonas gingivalis and Fusobacterium nucleatum, were administered to mice. These pathogens migrate to, and colonize, the gut, accelerating CD progression and aggravating colitis, and even systemic inflammation. In vitro experiments using a Caco-2/periodontal pathogen coculture revealed that P. gingivalis and F. nucleatum increased intestinal permeability by directly disrupting the tight junctions of intestinal epithelial cells.

CONCLUSION

Our findings strongly suggest that periodontal pathogens play a role in the relationship between periodontitis and CD. These results provide a basis for understanding the pathogenesis of Coexistence of CD and periodontal disease and may lead to the development of novel therapeutic strategies.

Microbiota of Saliva: A Non-invasive Diagnostic Tool

Potential of salivary microbiota as a non-invasive diagnostic tool for various diseases are explained in the present review. Traditional diagnostic methods rely on blood, which has limitations in terms of collection and biomarker specificity. We discuss the concept of normal flora and how disruptions in oral microbiota can be indicative of diseases. Saliva, harboring a diverse microbial community, offers promise as a diagnostic biomarker source for oral and non-oral conditions. We delve into the role of microbial dysbiosis in disease pathogenesis and the prospects of using biological indicators like dysbiosis for diagnosis, prediction, and monitoring. This review also emphasizes the significance of saliva microbiota in advancing early disease detection and timely intervention. We addressed the following research question and objectives: Can the microbiota of saliva serve as a non-invasive diagnostic tool for the early detection and monitoring of both oral and non-oral diseases? To achieve this, we will explore the normal flora of microorganisms in the oral cavity, the impact of microbial dysbiosis, and the potential of using specific pathogenic microorganisms as biomarkers. Additionally, we will investigate the correlation between oral and non-oral diseases by analyzing total saliva or site-specific dental biofilms for signs of symbiosis or dysbiosis. This research seeks to contribute valuable insights into the development of a non-invasive diagnostic approach with broad applications in healthcare.

Shotgun metagenomic analysis of saliva microbiome suggests Mogibacterium as a factor associated with chronic bacterial osteomyelitis

Osteomyelitis of the jaw is a severe inflammatory disorder that affects bones, and it is categorized into two main types: chronic bacterial and nonbacterial osteomyelitis. Although previous studies have investigated the association between these diseases and the oral microbiome, the specific taxa associated with each disease remain unknown. In this study, we conducted shotgun metagenome sequencing (≥10 Gb from ≥66,395,670 reads per sample) of bulk DNA extracted from saliva obtained from patients with chronic bacterial osteomyelitis (N = 5) and chronic nonbacterial osteomyelitis (N = 10). We then compared the taxonomic composition of the metagenome in terms of both taxonomic and sequence abundances with that of healthy controls (N = 5). Taxonomic profiling revealed a statistically significant increase in both the taxonomic and sequence abundance of Mogibacterium in cases of chronic bacterial osteomyelitis; however, such enrichment was not observed in chronic nonbacterial osteomyelitis. We also compared a previously reported core saliva microbiome (59 genera) with our data and found that out of the 74 genera detected in this study, 47 (including Mogibacterium) were not included in the previous meta-analysis. Additionally, we analyzed a core-genome tree of Mogibacterium from chronic bacterial osteomyelitis and healthy control samples along with a reference complete genome and found that Mogibacterium from both groups was indistinguishable at the core-genome and pan-genome levels. Although limited by the small sample size, our study provides novel evidence of a significant increase in Mogibacterium abundance in the chronic bacterial osteomyelitis group. Moreover, our study presents a comparative analysis of the taxonomic and sequence abundances of all genera detected using deep salivary shotgun metagenome data. The distinct enrichment of Mogibacterium suggests its potential as a marker to distinguish between patients with chronic nonbacterial osteomyelitis and chronic bacterial osteomyelitis, particularly at the early stages when differences are unclear.

Salivary Th17 cytokine, human β-defensin 1-3, and salivary scavenger and agglutinin levels in Crohn's disease

OBJECTIVES

Crohn's disease patients, who are prone to develop periodontal diseases, may carry genetic defects in their Th17 cytokine, human beta-defensin (hBD) 1-3, and salivary and scavenger agglutinin (SALSA) expressions. Biochemical composition of saliva reflects the oral consequences of systemic immune response modifications. Our aim was to evaluate the salivary Th17 cytokine, epithelial hBD 1-3, and SALSA levels in relation to Crohn's disease.

MATERIALS AND METHODS

This cross-sectional study included 42 Crohn's disease patients and 34 systemically healthy controls. Periodontal and dental indexes were measured, and stimulated saliva samples were collected. Salivary Th17 cytokine levels were analyzed by multiplex technique, and hBD 1-3 and SALSA levels by enzyme-linked immunosorbent assay.

RESULTS

There were 19 gingivitis and 11 initial periodontitis patients in the Crohn's disease group, and 15 gingivitis and 4 initial periodontitis in the control group. In comparison to controls, higher salivary Th17 cytokine levels were observed in Crohn's disease patients. No statistical difference was observed between Crohn's disease and control groups in terms of their salivary hBD 1-3 and SALSA levels. Based on the regression analysis, there is no independent association between Crohn's disease and salivary Th17 cytokine levels.

CONCLUSIONS

Crohn's disease does not relate to salivary antimicrobial hBD 1-3 or SALSA levels. While Crohn's disease patients have higher salivary Th17 cytokine levels in comparison to systemically healthy controls, an independent association between Crohn's disease and Th17 cytokine profile is still missing.

CLINICAL RELEVANCE

Diminished Th17 cytokine response in Crohn's disease, which might be related to genetic susceptibility, can be also visualized in saliva.

Causal Relationship between Gut Microbiota and Aneurysm: A Mendelian Randomization Study

INTRODUCTION

Observational studies have suggested a possible relationship between gut microbiota (GM) and aneurysm development. However, the nature of this association remains unclear due to the inherent limitations of observational research, such as reverse causation and confounding factors. To address this knowledge deficit, this study aimed to investigate and establish a causal link between GM and aneurysm development.

METHODS

Summary statistics regarding GM and aneurysms were collected from relevant genome-wide association studies. Two samples were used in mendelian randomization (MR). The principal MR technique utilized was inverse-variance weighting, a technique renowned for producing reliable causal effect estimations. Additional MR methods, including weighted median (WM), MR-Egger, MR-PRESSO, and simple mode methods, were employed to ensure the robustness of the aforementioned association and investigate potential biases. Sensitivity analyses were performed to determine the consistency of the MR findings.

RESULTS

Varying associations were observed between specific microbial taxa and the different aneurysms analyzed. A negative correlation was observed between aortic aneurysm (AA) and Lentisphaerae, Lentisphaeria, and Victivallales. Conversely, the genus FamilyXIIIUCG001 exhibited an increased risk association. Regarding abdominal AA, Victivallaceae showed a reduced risk, and Bilophila and Catenibacterium were associated with an increased risk. For thoracic AA, negative and positive correlations were observed with Lentisphaerae and Turicibacter, respectively. Lastly, in the case of cerebral aneurysm (CA), Firmicutes and Haemophilus were associated with a decreased risk, and Lachnoclostridium demonstrated an increased risk of association.

CONCLUSION

Our research has established causal relationships between specific GM components and various aneurysms. The obtained knowledge may aid in the development of microbiome-based interventions and the identification of novel biomarkers for targeted prevention strategies.

Association between the oral microbiome and brain resting state connectivity in schizophrenia

Recent microbiome-brain axis findings have shown evidence of the modulation of microbiome community as an environmental mediator in brain function and psychiatric illness. This work is focused on the role of the microbiome in understanding a rarely investigated environmental involvement in schizophrenia (SZ), especially in relation to brain circuit dysfunction. We leveraged high throughput microbial 16s rRNA sequencing and functional neuroimaging techniques to enable the delineation of microbiome-brain network links in SZ. N=213 SZ and healthy control (HC) subjects were assessed for the oral microbiome. Among them, 139 subjects were scanned by resting-state functional magnetic resonance imaging (rsfMRI) to derive brain functional connectivity. We found a significant microbiome compositional shift in SZ beta diversity (weighted UniFrac distance, p= 6×10 -3 ; Bray-Curtis distance p = 0.021). Fourteen microbial species involving pro-inflammatory and neurotransmitter signaling and H 2 S production, showed significant abundance alterations in SZ. Multivariate analysis revealed one pair of microbial and functional connectivity components showing a significant correlation of 0.46. Thirty five percent of microbial species and 87.8% of brain functional network connectivity from each component also showed significant differences between SZ and HC with strong performance in classifying SZ from HC, with an area under curve (AUC) = 0.84 and 0.87, respectively. The results suggest a potential link between oral microbiome dysbiosis and brain functional connectivity alteration in relation to SZ, possibly through immunological and neurotransmitter signaling pathways and the hypothalamic-pituitary-adrenal axis, supporting for future work in characterizing the role of oral microbiome in mediating effects on SZ brain functional activity.

Salivary microbiome in kidney diseases: A narrative review

Many research has been conducted since the microbiota's discovery that have focused on the role it plays in health and disease. Microbiota can be divided into categories like intestinal, oral, respiratory, and skin microbiota based on the specific localized areas. To maintain homeostasis and control immunological response, the microbial populations live in symbiosis with the host. On the other hand, dysbiosis of the microbiota can cause diseases including kidney diseases and the deregulation of body functioning. We discuss the current understanding of how various kidney diseases are caused by the salivary microbiome (SM) in this overview. First, we review the studies on the salivary microbiota in diverse clinical situations. The importance of the SM in diabetic kidney disease, chronic kidney disease, membranous nephropathy, and IgA nephropathy is next highlighted. We conclude that the characteristics of the SM of patients with various kidney diseases have revealed the potential of salivary microbial markers as noninvasive tool for the detection of various kidney diseases.

Alterations of the salivary microbiota in gastroesophageal reflux disease

OBJECTIVES

Gastroesophageal reflux disease (GERD) is among the most prevalent gastrointestinal disorders. The oral microbiota plays an important role in human health and may be altered by the presence of GERD. Here, we aimed to investigate the alterations of salivary microbiota in GERD patients.

METHODS

We collected clinical information and salivary samples from 60 individuals. All participants underwent combined pH/impedance monitoring measurement and submitted samples for salivary microbiota sequencing. According to acid exposure time and DeMeester score, participants were divided into two groups: GERD + (Group G) and GERD - (Group C).

RESULTS

There was no significant difference in alpha diversity between study groups. Regarding beta diversity, principal coordinate analysis plots indicated that the microbiota composition data of the participants were grouped within partial overlapping clusters. The statistical analysis of the distance matrices was performed using the Adonis test (p = 0.017). Based on linear discriminant analysis effect size, the relative abundances of the phylum Bacteroidetes, class Bacteroidia, order Bacteroidales, family Prevotellaceae, and genus unidentified_Prevotellaceae were enriched in Group G. Compared with Group C, the phylum Actinobacteria, classes unidentified_Actinobacteria and Bacilli, orders Micrococcales and Lactobacillales, families Micrococcaceae and Streptococcaceae, and genuses Rothia and Streptococcus were decreased in Group G. At the genus level, the abundances of Streptococcus and Rothia were negatively correlated with DeMeester score and acid exposure time.

CONCLUSIONS

This study revealed alterations of the salivary microbiota in GERD patients, suggesting that acid reflux changes the oral ecosystem.

Isolation, identification, and significance of salivary Veillonella spp., Prevotella spp., and Prevotella salivae in patients with inflammatory bowel disease

The global prevalence of inflammatory bowel disease (IBD) is on the rise, prompting significant attention from researchers worldwide. IBD entails chronic inflammatory disorders of the intestinal tract, characterized by alternating flares and remissions. Through high-throughput sequencing, numerous studies have unveiled a potential microbial signature for IBD patients showing intestinal enrichment of oral-associated bacteria. Simultaneously, the oral microbiome can be perturbed by intestinal inflammation. Our prior investigation, based on 16S rRNA amplicon sequencing, underscored elevated abundance of Veillonella spp. and Prevotella spp. in the salivary microbiomes of IBD patients. Noteworthy, Prevotella salivae emerged as a distinct species significantly associated with IBD. P. salivae is an under-recognized pathogen that was found to play a role in both oral and systemic diseases. In this study, we delve deeper into the salivary microbiomes of both IBD patients and healthy controls. Employing diverse cultivation techniques and real-time quantitative polymerase chain reactions (RT-qPCR), we gauged the prevalence and abundance of Veillonella spp., Prevotella spp., and P. salivae. Our isolation efforts yielded 407 and 168 strains of Veillonella spp., as well as 173 and 90 strains of Prevotella spp., from the saliva samples of IBD patients and healthy controls, respectively. Veillonella-vancomycin agar emerged as the discerning choice for optimal Veillonella spp. cultivation, while Schaedler kanamycin-vancomycin agar proved to be the most suitable medium for cultivating Prevotella spp. strains. Comparing our RT-qPCR findings to the previous 16S rRNA amplicon sequencing data, the results corroborated the higher abundance of Veillonella spp., Prevotella spp., and P. salivae in the saliva of IBD patients compared to healthy controls. However, it's worth noting that in contrast to RT-qPCR, the 16S rRNA amplicon sequencing data revealed greater absolute abundance of all three bacterial groups in both IBD patients and controls.

The oral bacterial microbiota facilitates the stratification for ulcerative colitis patients with oral ulcers

BACKGROUND

Clinically, a large part of inflammatory bowel disease (IBD) patients is complicated by oral lesions. Although previous studies proved oral microbial dysbiosis in IBD patients, the bacterial community in the gastrointestinal (GI) tract of those IBD patients combined with oral ulcers has not been profiled yet.

METHODS

In this study, we enrolled four groups of subjects, including healthy controls (CON), oral ulcer patients (OU), and ulcerative colitis patients with (UC_OU) and without (UC) oral ulcers. Bio-samples from three GI niches containing salivary, buccal, and fecal samples, were collected for 16S rRNA V3-V4 region sequencing. Bacterial abundance and related bio-functions were compared, and data showed that the fecal microbiota was more potent than salivary and buccal microbes in shaping the host immune system. ~ 22 UC and 10 UC_OU 5-aminosalicylate (5-ASA) routine treated patients were followed-up for six months; according to their treatment response (a decrease in the endoscopic Mayo score), they were further sub-grouped as responding and non-responding patients.

RESULTS

We found those UC patients complicated with oral ulcers presented weaker treatment response, and three oral bacterial genera, i.e., Fusobacterium, Oribacterium, and Campylobacter, might be connected with treatment responding. Additionally, the salivary microbiome could be an indicator of treatment responding in 5-ASA routine treatment rather than buccal or fecal ones.

CONCLUSIONS

The fecal microbiota had a strong effect on the host's immune indices, while the oral bacterial microbiota could help stratification for ulcerative colitis patients with oral ulcers. Additionally, the oral microbiota had the potential role in reflecting the treatment response of UC patients. Three oral bacteria genera (Fusobacterium, Oribacterium, and Campylobacter) might be involved in UC patients with oral ulcers lacking treatment responses, and monitoring oral microbiota may be meaningful in assessing the therapeutic response in UC patients.

Deciphering salivary microbiome signature in Crohn's disease patients with different factors contributing to dysbiosis

Crohn's disease (CD) is a chronic inflammatory bowel disease. An imbalanced microbiome (dysbiosis) can predispose to many diseases including CD. The role of oral dysbiosis in CD is poorly understood. We aimed to explore microbiome signature and dysbiosis of the salivary microbiome in CD patients, and correlate microbiota changes to the level of inflammation. Saliva samples were collected from healthy controls (HC) and CD patients (n = 40 per group). Salivary microbiome was analyzed by sequencing the entire 16S rRNA gene. Inflammatory biomarkers (C-reactive protein and calprotectin) were measured and correlated with microbiome diversity. Five dominant species were significantly enriched in CD, namely Veillonella dispar, Megasphaera stantonii, Prevotella jejuni, Dolosigranulum pigrum and Lactobacillus backii. Oral health had a significant impact on the microbiome since various significant features were cariogenic as Streptococcus mutans or periopathogenic such as Fusobacterium periodonticum. Furthermore, disease activity, duration and frequency of relapses impacted the oral microbiota. Treatment with monoclonal antibodies led to the emergence of a unique species called Simonsiella muelleri. Combining immunomodulatory agents with monoclonal antibodies significantly increased multiple pathogenic species such as Salmonella enterica, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa. Loss of diversity in CD was shown by multiple diversity indices. There was a significant negative correlation between gut inflammatory biomarkers (particularly calprotectin) and α-diversity, suggesting more inflammation associated with diversity loss in CD. Salivary dysbiosis was evident in CD patients, with unique microbiota signatures and perturbed species that can serve as disease biomarkers or potential targets for microbiota modulation. The interplay of various factors collectively contributed to dysbiosis, although each factor probably had a unique effect on the microbiome. The emergence of pathogenic bacteria in the oral cavity of CD patients is alarming since they can disturb gut homeostasis and induce inflammation by swallowing, or hematogenous spread of microbiota, their metabolites, or generated inflammatory mediators.

Alterations of oral microbiota are associated with the development and severity of acute pancreatitis

Acute pancreatitis (AP) is a common abdomen clinical emergency. Most APs have mild clinical symptoms and a good prognosis. However, about 20% of patients develop severe acute pancreatitis (SAP), increasing morbidity and mortality. The microbiome's impact on AP pathophysiology has received increasing attention. Hence, to explore changes in oral microbial composition in acute pancreatitis, we collected clinical information and oral saliva samples from 136 adult participants: 47 healthy controls, 43 acute mild AP (MAP), 29 moderate AP (MSAP), and 17 severe AP (SAP). Using 16S rRNA gene sequencing, 663,175 high-quality sequences were identified. The relative abundance and diversity of oral microorganisms in AP patients increased, with decreased beneficial bacteria such as Streptococcus, Neisseria, and Gemella, and increased Prevotella, Veillonella, Granulicatella, Actinomyces, and Peptostreptococcus in the AP group. Further changes in microbial composition occurred with increasing disease severity, including a decreased abundance of beneficial bacteria such as Neisseria, Haemophilus, and Gemella in MSAP and SAP compared to MAP. Moreover, the Lefse analysis showed that Prevotella, Peptostreptococcus, Actinomyces, and Porphyromonas were better microbial markers for AP. Therefore, oral microbiome changes could distinguish AP from healthy individuals and serve as an early novel predictor of disease severity in AP patients.

Unraveling the Link between Periodontitis and Inflammatory Bowel Disease: Challenges and Outlook

Periodontitis and Inflammatory Bowel Disease (IBD) are chronic inflammatory conditions, characterized by microbial dysbiosis and hyper-immunoinflammatory responses. Growing evidence suggest an interconnection between periodontitis and IBD, implying a shift from the traditional concept of independent diseases to a complex, reciprocal cycle. This review outlines the evidence supporting an "Oral-Gut" axis, marked by a higher prevalence of periodontitis in IBD patients and vice versa. The specific mechanisms linking periodontitis and IBD remain to be fully elucidated, but emerging evidence points to the ectopic colonization of the gut by oral bacteria, which promote intestinal inflammation by activating host immune responses. This review presents an in-depth examination of the interconnection between periodontitis and IBD, highlighting the shared microbiological and immunological pathways, and proposing a "multi-hit" hypothesis in the pathogenesis of periodontitis-mediated intestinal inflammation. Furthermore, the review underscores the critical need for a collaborative approach between dentists and gastroenterologists to provide holistic oral-systemic healthcare.

Current status and future prospects of stomatology research

Research in stomatology (dental medicine) continues to expand globally and is oriented towards solving clinical issues, focusing on clarifying the clinical relevance and potential mechanisms of oral‍-‍systemic connections via clinical epidemiology, oral microecological characterization, and the establishment of animal models. Interdisciplinary integration of materials science and tissue engineering with stomatology is expected to lead to the creation of innovative materials and technologies to better resolve the most prevalent and challenging clinical issues such as peri-implantitis, soft and hard tissue defects, and dentin hypersensitivity. With the rapid development of artificial intelligence (AI), 5th generation mobile communication technology (5G), and big data applications, "intelligent stomatology" is emerging to build models for better clinical diagnosis and management, accelerate the reform of education, and support the growth and advancement of scientific research. Here, we summarized the current research status, and listed the future prospects and limitations of these three aspects, aiming to provide a basis for more accurate etiological exploration, novel treatment methods, and abundant big data analysis in stomatology to promote the translation of research achievements into practical applications for both clinicians and the public.

Unraveling the Impact of Gut and Oral Microbiome on Gut Health in Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) is a complex disorder characterized by chronic inflammation of the gastrointestinal tract (GIT). IBD mainly includes two distinct diseases, namely Crohn's disease and ulcerative colitis. To date, the precise etiology of these conditions is not fully elucidated. Recent research has shed light on the significant role of the oral and gut microbiome in the development and progression of IBD and its collective influence on gut health. This review aims to investigate the connection between the oral and gut microbiome in the context of IBD, exploring the intricate interplay between these microbial communities and their impact on overall gut health. Recent advances in microbiome research have revealed a compelling link between the oral and gut microbiome, highlighting their pivotal role in maintaining overall health. The oral cavity and GIT are two interconnected ecosystems that harbor complex microbial communities implicated in IBD pathogenesis in several ways. Reduction in diversity and abundance of beneficial bacterial species with the colonization of opportunistic pathogens can induce gut inflammation. Some of these pathogens can arise from oral origin, especially in patients with oral diseases such as periodontitis. It is essential to discern the mechanisms of microbial transmission, the impact of oral health on the gut microbiome, and the potential role of dysbiosis in disease development. By elucidating this relationship, we can enhance our understanding of IBD pathogenesis and identify potential therapeutic avenues for managing the disease. Furthermore, innovative strategies for modulating the oral and gut microbiome can promote health and prevent disease occurrence and progression.

Metabarcoding of colonic cleansing fluid reveals unique bacterial members of mucosal microbiota associated with Inflammatory Bowel Disease

BACKGROUND

Inflammatory Bowel Disease (IBD) is a group of chronic idiopathic inflammatory diseases of the gastrointestinal (GI) tract associated with the dysbiosis of gut microbiota. Metabarcoding-based profiling of the gut microbiota of IBD patients is generally based on the stool samples collected from individual patients which rarely represent the mucosa-associated microbiota. The ideal sampling strategy for routine monitoring of the mucosal component of IBD has yet to be determined.

METHODS

We hereby compare the microbiota composition of the colonic cleansing fluid (CCF) collected during colonoscopy with stool samples from IBD patients. The relationship between IBD and gut microbiota was revealed through the application of the 16S rRNA amplicon sequencing-based metabarcoding approach. CCF and stool samples were collected from IBD patients with Crohn's disease and ulcerative colitis.

RESULTS

The present study shows significant differences in the microbial composition of CCF samples, presumably indicating changes in the mucosal microbiota of IBD patients as compared to the control group. Short-chain fatty acid-producing bacteria under the family Lachnospiraceae, the actinobacterial genus Bifidobacterium, the proteobacterial Sutterella and Raoultella are found to contribute to the microbial dysbiosis of the mucosal flora in IBD patients.

CONCLUSIONS

CCF microbiota has the capacity to distinguish IBD patients from healthy controls and, thus, may constitute an alternative analysis strategy for the early diagnosis and disease progression in IBD biomarker research.

Oral microbiome correlates with selected clinical biomarkers in individuals with no significant systemic disease

The oral microbiome is an important component of the microbiome in the human body. Although the association of the oral microbiome with various diseases, including periodontitis and cancer, has been reported, information on how the oral microbiome is related to health-related indicators in healthy populations is still insufficient. In this study, we examined the associations of the oral microbiome with 15 metabolic and 19 complete blood count (CBC)-based markers in 692 healthy Korean individuals. The richness of the oral microbiome was associated with four CBC markers and one metabolic marker. Compositional variation in the oral microbiome was significantly explained by four markers: fasting glucose, fasting insulin, white blood cell count, and total leukocyte count. Furthermore, we found that these biomarkers were associated with the relative abundances of numerous microbial genera, such as Treponema, TG5, and Tannerella. By identifying the relationship between the oral microbiome and clinical biomarkers in a healthy population, our study presents a direction for future studies on oral microbiome-based diagnosis and interventions.

Characterization of the oral and gut microbiome in children with obesity aged 3 to 5 years

The ever-increasing global prevalence of obesity has trended towards a younger age. The ecological characteristics and changes of the oral and gut microbial community during childhood are poorly understood.In this study, we analyzed the salivary and fecal microbiota of 30 children with obesity and 30 normal weight children aged 3-5 years via third-generation long-range DNA sequencing,with the aim of understanding the structure of childhood microbiota and identifying specific oral and gut microbial lineages and genera in children that may be associated with obesity.The results revealed significant variation in alpha diversity indices among the four groups (Chao1: P &lt; 0.001; observed species: P &lt; 0.001; Shannon &lt; 0.001). Principal coordinate analysis (PCoA) and nonmetric multidimensional scaling (NMDS) revealed significant differences in oral and gut microbial community structure between obesity and controls. The Firmicutes/Bacteroidetes (F/B) abundance ratios of oral and intestinal flora among children with obesity were higher than those of controls. The most abundant phyla and genera found in oral and intestinal flora were Firmicutes, Proteobacteria, Bacteroidetes, Neisseria, Bacteroides, Faecalibacterium, Streptococcus, Prevotella and so on. Linear discriminant analysis effect size (LEfSe) revealed higher proportions of Filifactor (LDA= 3.98; P &lt; 0.05) and Butyrivibrio (LDA = 2.54; P &lt; 0.001) in the oral microbiota of children with obesity, while the fecal microbiota of children with obesity were more enriched with Faecalibacterium (LDA = 5.02; P &lt; 0.001), Tyzzerella (LDA=3.25; P &lt; 0.01), Klebsiella (LDA = 4.31; P &lt; 0.05),which could be considered as dominant bacterial biomarkers for obesity groups.A total of 148 functional bacterial pathways were found to significantly differ in the oral and gut microbiota among controls and obesity using PICRUSt 2. Most predicted functional pathways were clustered in biosynthesis. In conclusion, This work suggests there were significant differences in oral and gut microbiota in controls and obesity groups, microbiota dysbiosis in childhood might have significant effect on the development of obesity.

Distribution characteristics of oral microbiota and its relationship with intestinal microbiota in patients with type 2 diabetes mellitus

Introduction

Type 2 diabetes mellitus (T2DM) has a high incidence rate globally, increasing the burden of death, disability, and the economy worldwide. Previous studies have found that the compositions of oral and intestinal microbiota changed respectively in T2DM; whether the changes were associated or interacted between the two sites and whether there were some associations between T2DM and the ectopic colonization of oral microbiota in the gut still need to be identified.

Research design and methods

We performed a cross-sectional observational study; 183 diabetes and 74 controls were enrolled. We used high-throughput sequencing technology to detect the V3-V4 region of 16S rRNA in oral and stool samples. The Source Tracker method was used to identify the proportion of the intestinal microbiota that ectopic colonized from the oral cavity.

Results

The oral marker bacteria of T2DM were found, such as Actinobacteria, Streptococcus, Rothia, and the intestinal marker bacteria were Bifidobacterium, Streptococcus, and Blautia at the genus level. Among them, Actinobacteria and Blautia played a vital role in different symbiotic relationships of oral and intestinal microbiota. The commonly distributed bacteria, such as Firmicutes, Bacteroidetes, and Actinobacteria, were found in both oral and intestine. Moreover, the relative abundance and composition of bacteria were different between the two sites. The glycine betaine degradation I pathway was the significantly up-regulated pathway in the oral and intestinal flora of T2DM. The main serum indexes related to oral and intestinal flora were inflammatory. The relative abundance of Proteobacteria in the intestine and the Spirochete in oral was positively correlated, and the correlation coefficient was the highest, was 0.240 (P<0.01). The proportion of ectopic colonization of oral flora in the gut of T2DM was 2.36%.

Conclusion

The dysbacteriosis exited in the oral and intestine simultaneously, and there were differences and connections in the flora composition at the two sites in T2DM. Ectopic colonization of oral flora in the intestine might relate to T2DM. Further, clarifying the oral-gut-transmitting bacteria can provide an essential reference for diagnosing and treating T2DM in the future.

The oral microbiome of treated and untreated chronic HCV infection: A preliminary study

OBJECTIVES

Chronic hepatitis C virus (HCV) infection is a debilitating disease that is lately treated using direct-acting antivirals (DAAs). Changes in the oral microbiome were detected in other liver diseases; however, oral microbiome was never investigated in patients having chronic HCV infection, whether pre- or post-treatment.

MATERIALS AND METHODS

This case-control preliminary study enrolled three equal groups: Group (I): untreated HCV patients; group (II): HCV patients who achieved viral clearance after DAA administration; and group (III): healthy controls. For each participant, a buccal swab was harvested and its 16S rRNA was sequenced.

RESULTS

The oral microbiome of chronic HCV patients had a significantly distinct bacterial community compared to healthy controls, characterized by high diversity and abundance of certain pathogenic species. These changes resemble that of oral lichen planus patients. After treatment by DAAs, the oral microbiome shifted to a community with partial similarity to both the diseased and the healthy ones.

CONCLUSIONS

Chronic HCV is associated with dysbiotic oral microbiome having abundant pathogenic bacteria. With HCV clearance by DAAs, the oral microbiome shifts to approach the healthy composition.

Periodontal disease is associated with increased gut colonization of pathogenic Haemophilus parainfluenzae in patients with Crohn's disease

Intestinal colonization of the oral bacterium Haemophilus parainfluenzae has been associated with Crohn's disease (CD) severity and progression. This study examines the role of periodontal disease (PD) as a modifier for colonization of H. parainfluenzae in patients with CD and explores the mechanisms behind H. parainfluenzae-mediated intestinal inflammation. Fifty subjects with and without CD were evaluated for the presence of PD, and their oral and fecal microbiomes were characterized. PD is associated with increased levels of H. parainfluenzae strains in subjects with CD. Oral inoculation of H. parainfluenzae elicits strain-dependent intestinal inflammation in murine models of inflammatory bowel disease, which is associated with increased intestinal interferon-γ (IFN-γ)+ CD4+ T cells and disruption of the host hypusination pathway. In summary, this study establishes a strain-specific pathogenic role of H. parainfluenzae in intestinal inflammation and highlights the potential effect of PD on intestinal colonization by pathogenic H. parainfluenzae strains in patients with CD.

Butyrate as a Potential Driver of a Dysbiotic Shift of the Tongue Microbiota

The tongue dorsum is colonized by a stable microbiota, mostly comprising common commensal taxa. However, the predominance of each taxon varies among individuals. We hypothesized that equilibrium in the tongue microbiota is affected by exposure to butyrate in the oral fluid, which is reported to affect the growth of specific microorganisms. In this study, the bacterial composition of the tongue microbiotas of 69 male adults was determined via 16S rRNA gene sequencing to investigate its relationship to n-butyric acid concentration in oral rinse samples. The tongue microbiotas of individuals with a higher n-butyric acid level had higher relative abundances of Prevotella histicola, Veillonella atypica, and Streptococcus parasanguinis and lower relative abundances of Neisseria subflava and Porphyromonas pasteri. Subsequently, tongue microbiota samples collected from 12 adults were cultivated for 13 h in basal medium containing mucin and different concentrations of sodium butyrate (0, 0.8, 1.6, and 3.2 mM) to assess its effect on the growth of tongue microbiota organisms. The bacterial composition of the cultivated tongue microbiotas also demonstrated a significant gradual shift with an increase in sodium butyrate levels in beta-diversity analysis. N. subflava was significantly less predominant in the microbiota after cultivation with an increased addition of sodium butyrate, although no statistical difference was observed in the other aforementioned taxa. These results suggest that butyrate in the oral fluid is partially involved in the dysbiotic shift of the tongue microbiota. IMPORTANCE Oral microbial populations that are always ingested with saliva have attracted increasing attention because more oral microorganisms than previously known reach distal organs, such as the lungs and intestinal tract, thereby affecting our health. However, although such organisms are predominately derived from the tongue dorsum, the dynamics and determinants of the tongue microbiota composition remain unclear. This study demonstrated that exposure to butyrate could lead to a dysbiotic shift in the tongue microbiota using an observational epidemiological and microbiota cultivation approach. This result adds a new dimension to tongue microbiota ecology.

Computational estimation of sediment symbiotic bacterial structures of seagrasses overgrowing downstream of onshore aquaculture

Coastal seagrass meadows are essential in blue carbon and aquatic ecosystem services. However, this ecosystem has suffered severe eutrophication and destruction due to the expansion of aquaculture. Therefore, methods for the flourishing of seagrass are still being explored. Here, data from 49 public coastal surveys on the distribution of seagrass and seaweed around the onshore aquaculture facilities are revalidated, and an exceptional area where the seagrass Zostera marina thrives was found near the shore downstream of the onshore aquaculture facility. To evaluate the characteristics of the sediment for growing seagrass, physicochemical properties and bacterial ecological evaluations of the sediment were conducted. Evaluation of chemical properties in seagrass sediments confirmed a significant increase in total carbon and a decrease in zinc content. Association analysis and linear discriminant analysis refined bacterial candidates specified in seagrass overgrown- and nonovergrown-sediment. Energy landscape analysis indicated that the symbiotic bacterial groups of seagrass sediment were strongly affected by the distance close to the seagrass-growing aquaculture facility despite their bacterial population appearing to fluctuate seasonally. The bacterial population there showed an apparent decrease in the pathogen candidates belonging to the order Flavobacteriales. Moreover, structure equation modeling and a linear non-Gaussian acyclic model based on the machine learning data estimated an optimal sediment symbiotic bacterial group candidate for seagrass growth as follows: the Lachnospiraceae and Ruminococcaceae families as gut-inhabitant bacteria, Rhodobacteraceae as photosynthetic bacteria, and Desulfobulbaceae as cable bacteria modulating oxygen or nitrate reduction and oxidation of sulfide. These observations confer a novel perspective on the sediment symbiotic bacterial structures critical for blue carbon and low-pathogenic marine ecosystems in aquaculture.

Association between inflammatory bowel disease and periodontitis: A bidirectional two-sample Mendelian randomization study

AIM

This Mendelian randomization (MR) study was performed to explore the potential bidirectional causal association between inflammatory bowel disease (IBD) and periodontitis.

MATERIALS AND METHODS

We used genetic instruments from the genome-wide association study summary statistics of European descent for IBD (12,882 cases and 21,770 controls) to investigate the association with periodontitis (3046 cases and 195,395 controls) and vice versa. The radial inverse-variance weighted method was carried out to obtain the primary causal estimates, and the robustness of the results was assessed by a series of sensitivity analyses. Due to multiple testing, associations with p values <.008 were considered as statistically significant, and p values ≥.008 and <.05 were considered as suggestively significant.

RESULTS

In the primary causal estimates, IBD as a whole was associated with an increased risk of periodontitis (odds ratio [OR], 1.060; 95% confidence interval [CI], 1.017; 1.105; p = .006). Subtype analyses showed that ulcerative colitis (UC) was associated with periodontitis (OR, 1.074; 95% CI 1.029; 1.122; p = .001), while Crohn's disease (CD) was not. Regarding the reverse direction, periodontitis showed a suggestive association with IBD as a whole (OR, 1.065; 95% CI 1.013; 1.119; p = .014). Subtype analyses revealed that periodontitis was associated with CD (OR, 1.100; 95% CI 1.038; 1.167; p = .001) but not UC. The final models after outlier removal showed no obvious pleiotropy, indicating that our primary analysis results were reliable.

CONCLUSIONS

The present MR study provides moderate evidence on the bidirectional causal relationship between IBD and periodontitis. The bidirectional increased risk found in our study was marginal and, possibly, of limited clinical relevance. More studies are needed to support the findings of our current study.