A Reciprocal Link between Oral, Gut Microbiota during Periodontitis: The Potential Role of Probiotics in Reducing Dysbiosis-Induced Inflammation

Artesunate ameliorates diabetic xerostomia in rats through regulating oral microbiota and metabolic profile in salivary gland based on NF-κB/NLRP3 signaling pathway

BACKGROUND

Artemisia annua. L, as a valuable Chinese medicine, has been applied for millennia in China. Its major active ingredient, artemisinin, has demonstrated diverse pharmacological properties, including anti-inflammatory, antioxidant, and anti-diabetic effects. Recent studies suggest that artesunate (ART), an artemisinin derivative, exhibits promising therapeutic effects on diabetic complications. Nevertheless, the role and underlying mechanisms of ART in the treatment of diabetic xerostomia (DX) remain unclear.

AIM

This study aimed to elucidate the effects of ART on DX in a type 2 diabetes mellitus (T2DM) rat model, primarily from the perspective of oral microbiota and salivary gland (SG) metabolism, and to further explore potential mechanisms involved.

METHODS

Various assessments including blood levels, insulin resistance (IR), saliva flow rate, as well as histological analyses through hematoxylin and eosin and Masson staining were performed to verify the reliability of DX model and protective effects of ART on the DX. Untargeted metabolomics and 16S rDNA sequencing were employed to respectively evaluate effects of ART on metabolite changes in SG and oral microbiota in the DX rats. Network pharmacology was employed to predict key pathways and targets with critical roles in ART's therapeutic effect on DX. Additionally, molecular docking and molecular dynamics (MD) simulations were utilized to evaluate interactions between ART and the identified key pathway targets. Surface plasmon resonance (SPR) experiment was performed to verify our computational predictions. Finally, molecular biology experiments were conducted to further validate the identified key pathway targets.

RESULTS

ART treatment ameliorated the hyperglycemia, IR and hyposalivation, and ameliorated pathological changes and oxidative stress of SGs in the DX rats. Besides, 16S rDNA sequencing suggested that ART alleviated the perturbation of oral microbiota (such as Veillonella, Lactobacillus, Clostridium sensu stricto 1, Escherichia-Shigella, and Dubosiella). Untargeted metabolomics revealed that steroid hormone biosynthesis, taurine and hypotaurine metabolism of SGs in the DX rats were partially corrected by ART treatment. Correlation analysis demonstrated an obvious association between the oral microbiota species and SG metabolites. Network pharmacology analysis identified NF-κB pathway as a critical pathway of ART in treating DX. Meanwhile, molecular docking and MD simulation suggested stable binding of ART to NF-κB/NLRP3 pathway targets, particularly NLRP3. Furthermore, SPR confirmed a stable binding of ART to NLRP3, a key target in the NF-κB/NLRP3 pathway. Oxidative stress indicators involved in NF-κB pathway, including MDA and SOD levels, were significantly reduced after ART intervention. Western blotting and qRT-PCR experiments further revealed that ART inhibited increase of NF-κB/NLRP3 pathway related targets expression, including NF-κB, NLRP3, Caspase1, IL-1β, IL-18, TNF-α, and IL-6 in the SGs of DX rats.

CONCLUSION

ART exerted beneficial therapeutic effects on DX by modulating oral microbiota dysbiosis and restoring SG's metabolic profiles, and inhibiting activation of NF-κB/NLRP3 pathway, suggesting its potential novel application in DX treatment.

Causal relationship between gut microbiota and dental caries: a two-sample mendelian randomization study

BACKGROUND

In recent years, an increasing number of studies have revealed a close relationship between the gut microbiota and a variety of human diseases. At the same time, it has also been shown that dysregulation of the oral microbiota may lead to changes in the gut microbiota. However, it remains unclear whether the gut microbiota affects the occurrence and development of oral diseases. Therefore, the aim of this study was to explore the potential effects of gut microbiota on dental caries and to reveal possible mechanisms of the gut-oral microbiota axis.

METHODS

First, gut microbiota and dental caries data from genome-wide association studies (GWAS) were analyzed using Mendelian randomization analysis. Inverse variance weighted (IVW) was used as the main criterion (P value < 0.05). Then, MR-Egger regression, IVW regression and leave-one-out tests were used to test the reliability and stability of the mendelian randomization results. Finally, the potential mechanisms and significance of the relationship between gut microbiota and dental caries were explored.

RESULTS

The analysis showed that Eubacteriumbrachygroup [odds ratio (OR) = 1.001, 95% confidence interval (CI): 1.000-1.002, P = 0.046] and Terrisporobacter (OR = 1.002, 95% CI: 1.0001-1.0041, P = 0.035) were positively correlated with dental caries. Escherichia.Shigella (OR = 0.997, 95% CI: 0.995-0.999, P = 0.047), Oscillibacter (OR = 0.998, 95% CI: 0.997-0.999, P = 0.038), RuminococcaceaeUCG014 (OR = 0.998, 95% CI: 0.996-0.999, P = 0.044) and Oscillospira (OR = 0.997, 95% CI: 0.995-0.999, P = 0.038) were negatively correlated with dental caries.

CONCLUSION

The present study demonstrated a significant causal relationship between the gut microbiota and the development of dental caries, providing new insights into influencing the development of dental caries by affecting the composition of the gut microbiota.

Chronic Inflammation and Glycemic Control: Exploring the Bidirectional Link Between Periodontitis and Diabetes

Periodontitis and diabetes mellitus are two highly prevalent chronic conditions that share a bidirectional relationship, significantly impacting public health. Periodontitis, a gum inflammation caused by microbial dysbiosis, aggravates glycemic control in diabetics, while uncontrolled diabetes heightens periodontitis severity. These conditions create a vicious cycle, where inflammation and microbial dysbiosis mutually drive disease progression, exacerbating systemic health. The underlying mechanisms involve inflammation, immune dysfunction, and microbial dysbiosis, with both diseases contributing to a chain of chronic inflammation that exacerbates systemic health. This relationship is significant because managing one condition can significantly impact the other. In diabetic individuals, interventions such as periodontal therapy have shown effectiveness in improving glycemic control, underscoring the potential of integrated strategies for managing these conditions simultaneously. In this review, we highlight the importance of a deeper understanding of the molecular and immunological interactions between these diseases is essential for developing integrated therapeutic approaches, with the potential to enhance the quality of life of the patient significantly.

Intestinal Dysbiosis: Exploring Definition, Associated Symptoms, and Perspectives for a Comprehensive Understanding - a Scoping Review

Dysbiosis is a clinical condition marked by altered gut microbiota resulting from external and internal host factors. It is strongly associated with gastrointestinal and extraintestinal alterations, so its symptomatology is broad and nonspecific. To date, gaps remain that limit professionals from making a timely diagnosis and prescribing the appropriate treatment. We aim to synthesize existing literature regarding clinical parameters for the early detection of patients with intestinal dysbiosis and the clinical events in which the use of probiotics as adjuvant therapy is most frequently reported. A scoping review of the literature was conducted in PubMed, Embase, Cochrane, and BVS (Biblioteca Virtual en Salud in Spanish) databases for articles published in the last 5 years. Primary studies and literature reviews related to clinical presentation, dysbiosis screening, and probiotics as adjuvant therapy for adult and pediatric patients were included. Twenty-three articles were retrieved in which the most frequently reported symptoms were abdominal distension, abdominal pain, and diarrhea. Chronic and metabolic diseases where the conditions most strongly associated with dysbiosis. Depending on symptomatology and etiology, dysbiosis is often treated with probiotics. Dysbiosis, often linked to diarrhea, should be considered with other symptoms like abdominal distension and pain, along with predisposing conditions and patient risk factors. Probiotics are commonly used as co-adjuvant treatments for antibiotic-associated diarrhea, irritable bowel syndrome, and childhood allergic diseases. The most commonly used probiotics were Weizmannia coagulans (formerly B. coagulans), Alkalihalobacillus clausii (formerly Bacillus clausii), Lacticaseibacillus rhamnosus, Limosilactobacillus reuteri, and Saccharomyces boulardii.

Efficacy of toothpaste containing OPTIMEALTH® OR in inhibiting dental plaque and gingivitis: A randomized controlled trial

BACKGROUND

This randomized double-blind, placebo-controlled clinical trial evaluated the effects of 2% OPTIMEALTH® OR toothpaste in regulating dental plaque microbiota and alleviating gingivitis.

METHODS

Subjects were randomly assigned to the placebo group and test group. They were instructed to brush their teeth with placebo toothpaste (placebo group) or OPTIMEALTH® OR toothpaste (test group) for a continuous 4 weeks. Clinical indices of plaque index, gingival index, and bleeding on probe (%) were examined, and images of dental plaque staining were captured at baseline and after 2 and 4 weeks. The plaque microbiome was analyzed by 16s rDNA amplicon sequencing at baseline and after 4 weeks.

RESULTS

Thirty-two participants with similar characteristics were recruited. After using OPTIMEALTH® OR toothpaste for 4 weeks, a decrease of 27.05% (P < .01), 8.29% (P > .05), and 47.44% (P < .05) in plaque index, gingival index, and bleeding on probe (%) scores was observed compared to the baseline, respectively. The extent of decline in these indices is greater than that in the placebo group. A decrease in dental plaque could be observed after 2 and 4 weeks in the test group. The 16s rDNA sequencing results showed that the observed species index and Chao index, but not the Shannon index and beta diversity, were reduced significantly after using OPTIMEALTH® OR toothpaste for 4 weeks. In addition, compared with the placebo group, using OPTIMEALTH® OR toothpaste reduced the abundance of bacterial species such as Veillonella parvula and Prevotella denticola.

CONCLUSION

Brushing teeth with 2% OPTIMEALTH® OR-fortified toothpaste could effectively reduce dental plaque and regulate plaque microbiota.

Impact of Hyaluronic Acid and Other Re-Epithelializing Agents in Periodontal Regeneration: A Molecular Perspective

This narrative review delves into the molecular mechanisms of hyaluronic acid (HA) and re-epithelializing agents in the context of periodontal regeneration. Periodontitis, characterized by chronic inflammation and the destruction of tooth-supporting tissues, presents a significant challenge in restorative dentistry. Traditional non-surgical therapies (NSPTs) sometimes fail to fully manage subgingival biofilms and could benefit from adjunctive treatments. HA, with its antibacterial, antifungal, anti-inflammatory, angiogenic, and osteoinductive properties, offers promising therapeutic potential. This review synthesizes the current literature on the bioactive effects of HA and re-epithelializing agents, such as growth factors and biomaterials, in promoting cell migration, proliferation, and extracellular matrix (ECM) synthesis. By modulating signaling pathways like the Wnt/β-catenin, TGF-β, and CD44 interaction pathways, HA enhances wound healing processes and tissue regeneration. Additionally, the role of HA in facilitating cellular crosstalk between epithelial and connective tissues is highlighted, as it impacts the inflammatory response and ECM remodeling. This review also explores the combined use of HA with growth factors and cytokines in wound healing, revealing how these agents interact synergistically to optimize periodontal regeneration. Future perspectives emphasize the need for further clinical trials to evaluate the long-term outcomes of these therapies and their potential integration into periodontal treatment paradigms.

Periodontal bacteria influence systemic diseases through the gut microbiota

Many systemic diseases, including Alzheimer disease (AD), diabetes mellitus (DM) and cardiovascular disease, are associated with microbiota dysbiosis. The oral and intestinal microbiota are directly connected anatomically, and communicate with each other through the oral-gut microbiome axis to establish and maintain host microbial homeostasis. In addition to directly, periodontal bacteria may also be indirectly involved in the regulation of systemic health and disease through the disturbed gut. This paper provides evidence for the role of periodontal bacteria in systemic diseases via the oral-gut axis and the far-reaching implications of maintaining periodontal health in reducing the risk of many intestinal and parenteral diseases. This may provide insight into the underlying pathogenesis of many systemic diseases and the search for new preventive and therapeutic strategies.

The Connection Between the Oral Microbiota and the Kynurenine Pathway: Insights into Oral and Certain Systemic Disorders

The oral microbiome, comprising bacteria, fungi, viruses, and protozoa, is essential for maintaining both oral and systemic health. This complex ecosystem includes over 700 bacterial species, such as Streptococcus mutans, which contributes to dental caries through acid production that demineralizes tooth enamel. Fungi like Candida and pathogens such as Porphyromonas gingivalis are also significant, as they can lead to periodontal diseases through inflammation and destruction of tooth-supporting structures. Dysbiosis, or microbial imbalance, is a key factor in the development of these oral diseases. Understanding the composition and functions of the oral microbiome is vital for creating targeted therapies for these conditions. Additionally, the kynurenine pathway, which processes the amino acid tryptophan, plays a crucial role in immune regulation, neuroprotection, and inflammation. Oral bacteria can metabolize tryptophan, influencing the production of kynurenine, kynurenic acid, and quinolinic acid, thereby affecting the kynurenine system. The balance of microbial species in the oral cavity can impact tryptophan levels and its metabolites. This narrative review aims to explore the relationship between the oral microbiome, oral diseases, and the kynurenine system in relation to certain systemic diseases.

Daily Probiotic Ayran Intake Reduces Gingival Inflammation: An Experimental Gingivitis Study

PURPOSE

This study investigates the effects of daily consumption of a probiotic ayran drink on gingival inflammation and the development of experimental gingivitis.

MATERIALS AND METHODS

This randomised, double-blind, placebo-controlled trial involved 54 volunteer students. The participants were randomly assigned to two groups: the control group received regular ayran for 42 days, while the test group received probiotic enriched ayran (including Lactobacillus acidophilus and Bifidobacterium bifidum) for 42 days twice a day. After 42 days, mechanical plaque control was stopped for 5 days. The plaque index (PI), gingival index (GI), probing bleeding (BOP), and probing depth (PPD) were measured at baseline, day 42, and day 47. At the same time, gingival crevicular fluid was taken for matrix metalloproteinase-8 examination.

RESULTS

The mean scores of BOP, GI, PI, and MMP-8 levels increases in both groups following the 5-day experimental gingivitis period compared to baseline and day 42. Patients using probiotic ayran had significantly less PI, GI, BOP scores and MPP-8 values (p = 0.002; p 0.001; p 0.001; p = 0.001; p = 0.001, respectively) at day 47 compared to the control group. No statistically significant differences in probing pocket depth (PPD) were observed at any time point.

CONCLUSION

The present study suggests that daily consumption of a probiotic ayran drink containing Lactobacillus acidophilus and Bifidobacterium bifidum statistically significantly lowers clinical and immunological markers of gingival inflammation.

Oral and Gut Microbiota Dysbiosis Due to Periodontitis: Systemic Implications and Links to Gastrointestinal Cancer: A Narrative Review

Periodontitis can disrupt oral and gut microbiota, leading to dysbiosis that affects overall systemic health. Besides the spread of periodontal pathogens by the hematogenous route, they can also be translocated into the gastrointestinal tract, possibly intervening in the neoplastic process in the gastrointestinal tract. This manuscript reviews the relationship between oral and gut microbiota due to periodontitis, discussing systemic health implications and potential links to gastrointestinal cancer. This article highlights the significance and effect of dysbiosis in the gut, emphasizing the importance of maintaining oral health to prevent systemic diseases. Lastly, it will go through therapeutic innovations such as probiotics and oral microbiota analysis tools for systemic disease detection. These findings will mark the integration of oral health management in clinical practice to lower systemic disease risk and improve overall patient outcomes. Aim of work: This manuscript aims to unravel the pathological interaction between oral and gut microbiota and their bidirectional effect on systemic diseases. Materials and methods: The review was performed using the MEDLINE and ScienceDirect databases. Reviewed articles were published in English between the year 2015 and 2024. The search used keywords such as ("oral microbiota" AND "periodontal disease") OR ("oral microbiota" AND "gastrointestinal cancer") OR ("Porphyromonas gingivalis" AND "periodontal disease") OR ("Helicobacter pylori" AND "gastric cancer") OR ("gut microbiome" AND "inflammatory bowel disease") OR ("oral microbiome" AND "systemic diseases"). Conclusions: The dysbiotic change in the oral cavity due to periodontitis is linked directly and indirectly to systemic diseases such as IBS, neurodegenerative diseases, muscle joint diseases, respiratory infections, and gastrointestinal cancer; this underscores the importance of maintaining oral hygiene for prophylaxis of oral diseases and the prevention of systemic diseases. A better understanding of the interconnections between oral health and systemic diseases will integrate oral health management to offer new prevention, diagnostic, and treatment opportunities to improve overall patient outcomes.

Correlation Between Gut Microbiota Composition and Serum Interleukin 17 (IL-17) in Mice With Type 2 Diabetes and Experimental Periodontitis

Objective To preliminarily explore the composition characteristics of gut microbiota in mice with type 2 diabetes mellitus (T2DM) and experimental periodontitis, and their correlation with serum IL-17 levels, aiming to provide new insights and evidence for related experimental studies. Methods A total of 42 SPF-grade C57BL/6J mice were randomly selected, with 24 used for T2DM modeling. Successfully modeled T2DM mice were divided into the T2DM group (ND group, n=8) and T2DM with experimental periodontitis group (PD group, n=8). Non-T2DM mice were divided into the blank control group (NC group, n=8) and the experimental periodontitis group (NP group, n=8). After modeling, body weight and fasting plasma glucose (FPG) were measured weekly. Each group of mice underwent an oral glucose tolerance test (OGTT) and an insulin tolerance test (ITT). Six weeks after modeling experimental periodontitis, serum IL-17 levels were measured using ELISA, intestinal inflammation was assessed using HE staining, and gut microbiota composition in cecal contents was analyzed by 16S rRNA sequencing to determine its correlation with serum IL-17 levels. Results FPG in the PD group was higher than in the ND group, with a statistically significant difference in the 12th week (p<0.05). The glucose tolerance level in the PD group was lower than in the ND group (p<0.01). Compared with the NC group, other groups showed varying degrees of inflammatory cell infiltration in the intestinal mucosa, and serum IL-17 levels were lower in both the ND and PD groups compared to the NC group (p<0.01), with the PD group also lower than the NP group (p<0.01). The Shannon and Pielou-e indices of gut microbiota in the PD group were significantly lower than those in the NP group (p<0.05). In terms of microbiota composition, Firmicutes were increased in both the ND and PD groups compared to the NC and NP groups (p<0.05), while Bacteroidetes were decreased (p<0.05). Proteobacteria were increased in the PD group compared to the ND group (p<0.05). The abundance of Bacteroidetes and the Bacteroidetes/Firmicutes ratio was moderately positively correlated with serum IL-17 levels (p<0.01) and moderately negatively correlated with blood glucose levels (p<0.01); serum IL-17 levels were strongly negatively correlated with blood glucose levels (p<0.01). Conclusion Comorbidity of experimental periodontitis and T2DM may exacerbate glucose metabolism impairment in T2DM mice by increasing the abundance of Proteobacteria and intestinal mucosal damage. Serum IL-17 levels may serve as an indicator of gut microbiota dysbiosis in T2DM mice with experimental periodontitis.

Role of the intestinal microbiome and its therapeutic intervention in cardiovascular disorder

The gut microbiome is a heterogeneous population of microbes comprising viruses, bacteria, fungi, and protozoa. Such a microbiome is essential for sustaining host equilibrium, and its impact on human health can be altered by a variety of factors such as external variables, social behavior, age, nutrition, and genetics. Gut microbes' imbalances are related to a variety of chronic diseases including cancer, obesity, and digestive disorders. Globally, recent findings show that intestinal microbes have a significant role in the formation of cardiovascular disease (CVD), which is still the primary cause of fatalities. Atherosclerosis, hypertension, diabetes, inflammation, and some inherited variables are all cardiovascular risk variables. However, studies found correlations between metabolism, intestinal flora, and dietary intake. Variations in the diversity of gut microbes and changes in their activity are thought to influence CVD etiology. Furthermore, the gut microbiota acts as an endocrine organ, producing bioactive metabolites such as TMA (trimethylamine)/TMAO (trimethylamine N-oxide), SCFA (short-chain fatty acids), and bile acids, which have a substantial impact on host wellness and disease by multiple mechanisms. The purpose of this overview is to compile current evidence highlighting the intricate links between gut microbiota, metabolites, and the development of CVD. It focuses on how intestinal dysbiosis promotes CVD risk factors such as heart failure, hypertension, and atherosclerosis. This review explores the normal physiology of intestinal microbes and potential techniques for targeting gut bacteria for CVD treatment using various microbial metabolites. It also examines the significance of gut bacteria in disease treatment, including supplements, prebiotics, probiotics, antibiotic therapies, and fecal transplantation, which is an innovative approach to the management of CVD. As a result, gut bacteria and metabolic pathways become increasingly attractive as potential targets for CVD intervention.

Mouthwashes: Alternatives and Future Directions

This narrative review summarises "alternative" or "natural" over-the-counter (OTC) mouthwashes not covered elsewhere in this supplement and newly emerging products, as potential mouthwashes of the future. The "natural" mouthwashes reviewed include saltwater, baking soda, coconut oil, charcoal, propolis, seaweeds, and probiotics. Other than essential oils, it is apparent that their clinical effectiveness is still under debate, but there is some evidence to suggest that propolis reduces plaque and gingivitis. This review also covers the host immune response, via novel anti-inmmunomodulant mouthwashes, such as erythropoietin to reduce inflammation with oral mucositis (OM) after radiotherapy. The emerging concept of nanoparticle-containing mouthwashes, such as iron oxide, is further discussed for OM, this agent having the potential for more targeted delivery of chemical antimicrobials. Unfortunately, there are impacts on the environment of widening mouthwash use with more new products, including increased use of packaging, antimicrobial resistance, and possible detrimental effects on marine life. Further, there are roadblocks, relating to regularly approvals and side effects, that still need to be overcome for any OTC deivered immunomodulant or nanoformulation mouthwashes. Despite these caveats, there are many new mouthwashes under development, which could help manage major oral diseases such as caries, gingivitis, and periodontal disease.

Advancing microbiome research with machine learning: key findings from the ML4Microbiome COST action

The rapid development of machine learning (ML) techniques has opened up the data-dense field of microbiome research for novel therapeutic, diagnostic, and prognostic applications targeting a wide range of disorders, which could substantially improve healthcare practices in the era of precision medicine. However, several challenges must be addressed to exploit the benefits of ML in this field fully. In particular, there is a need to establish "gold standard" protocols for conducting ML analysis experiments and improve interactions between microbiome researchers and ML experts. The Machine Learning Techniques in Human Microbiome Studies (ML4Microbiome) COST Action CA18131 is a European network established in 2019 to promote collaboration between discovery-oriented microbiome researchers and data-driven ML experts to optimize and standardize ML approaches for microbiome analysis. This perspective paper presents the key achievements of ML4Microbiome, which include identifying predictive and discriminatory 'omics' features, improving repeatability and comparability, developing automation procedures, and defining priority areas for the novel development of ML methods targeting the microbiome. The insights gained from ML4Microbiome will help to maximize the potential of ML in microbiome research and pave the way for new and improved healthcare practices.

The increasing importance of the oral microbiome in periodontal health and disease

Herein, the aim is to discuss the current knowledge of microbiome and periodontal diseases. Current treatment strategies include mechanical therapy such as root planing, scaling, deep pocket debridement and antimicrobial chemotherapy as an adjuvant therapy. Among promising therapeutic strategies, dental probiotics and oral microbiome transplantation have gained attention, and may be used to treat bacterial imbalances by competing with pathogenic bacteria for nutrients and adhesion surfaces, as well as probiotics targeting the gut microbiome. Development of strategies to prevent and treat periodontal diseases are warranted as both are highly prevalent and can affect human health. Further studies are necessary to better comprehend the microbiome in order to develop innovative preventative measures as well as efficacious therapies against periodontal diseases.

Human oral mucosa and oral microbiome interactions following supragingival plaque reconstitution in healthy volunteers: a diet-controlled balanced design proof-of-concept model to investigate oral pathologies

Changes in the oral microbiome may contribute to oral pathologies, especially in patients undergoing cancer therapy. Interactions between oral microbiome and oral mucosa may exacerbate inflammation. We determined whether probiotic-controlled plaque formation could impact proximal oral mucosa gene expression profiles in healthy volunteers. A 3-weeks balanced sample collection design from healthy volunteers (HVs) was implemented. At Week-1 plaques samples and labial mucosa brush biopsies were obtained from HVs in the morning (N = 4) and/or in the afternoon (N = 4), and groups were flipped at Week-3. A fruit yogurt and tea diet were given 2-4hrs before sample collection. mRNA gene expression analysis was completed using RNA-Seq and DESeq2. Bacterial taxa relative abundance was determined by 16S HOMINGS. Bacterial diversity changes and metabolic pathway enrichment were determined using PRIMERv7 and LEfSe programs. Alpha- and beta-diversities did not differ morning (AM) vs. afternoon (PM). The most affected KEGG pathway was Toll-like receptor signaling in oral mucosa. Eighteen human genes and nine bacterial genes were differentially expressed in plaque samples. Increased activity for 'caries-free' health-associated calcifying Corynebacterium matruchotii and reduced activity for Aggregatibacter aphrophilus, an opportunistic pathogen, were observed. Microbial diversity was not altered after 8 hours plaque formation in healthy individuals as opposed to gene expression.

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.

Functional Foods: A Promising Strategy for Restoring Gut Microbiota Diversity Impacted by SARS-CoV-2 Variants

Natural herbs and functional foods contain bioactive molecules capable of augmenting the immune system and mediating anti-viral functions. Functional foods, such as prebiotics, probiotics, and dietary fibers, have been shown to have positive effects on gut microbiota diversity and immune function. The use of functional foods has been linked to enhanced immunity, regeneration, improved cognitive function, maintenance of gut microbiota, and significant improvement in overall health. The gut microbiota plays a critical role in maintaining overall health and immune function, and disruptions to its balance have been linked to various health problems. SARS-CoV-2 infection has been shown to affect gut microbiota diversity, and the emergence of variants poses new challenges to combat the virus. SARS-CoV-2 recognizes and infects human cells through ACE2 receptors prevalent in lung and gut epithelial cells. Humans are prone to SARS-CoV-2 infection because their respiratory and gastrointestinal tracts are rich in microbial diversity and contain high levels of ACE2 and TMPRSS2. This review article explores the potential use of functional foods in mitigating the impact of SARS-CoV-2 variants on gut microbiota diversity, and the potential use of functional foods as a strategy to combat these effects.

Confounding in observational studies evaluating the association between Alzheimer's disease and periodontal disease: A systematic review

Background

Studies investigating the association between periodontitis and Alzheimer's disease (AD) suggested indirect (periodontitis would increase the circulation of inflammation-inducible molecules) and direct (periodontopathogens might colonize brains affected by Alzheimer's disease) pathways. While there seems to be a positive relationship between periodontitis and AD, concerns have been raised about the role of confounding.

Aim

To systematically review the literature to assess confounding and their level of heterogeneity in the association between periodontitis and AD. Also, to examine data reporting and interpretation regarding confounding bias.

Methods

This review followed the PRISMA guidelines and was registered within PROSPERO. Electronic searches were performed in seven main databases and three others to capture the "grey literature". The PECO strategy was used to identify observational studies (cross-sectional, case-control, or cohort studies) assessing the association between periodontal disease and AD without restricting publication language and year. Critical appraisal was performed according to the Joanna Briggs Institute guidelines. Confounders were evaluated following a two-step approach.

Results

A total of 3255 studies were found, of which 18 (13 case-control, four cross-sectional, and one cohort) met the eligibility criteria. Participants with AD were 1399 (mean age 64 ± 9 to 84.8 ± 5.6 years), whereas those without AD were 1730 (mean age 62.6 ± 7.1 to 81.4 ± 4.6). Female patients composed most of the sample for both groups. The confounding variables "age" and "sex" were present in all studies. Four studies used the 2017 AAP/EFP periodontal classification. Most studies had a low risk of bias. Fifty percent of the articles did not consider confounding; variation in the adjustment approaches was observed. Additionally, 62% of the studies did not mention bias, and 40% did not discuss any limitations about confounders.

Conclusions

Given the study's limitations, caution must be taken to properly interpret the association between periodontitis and AD.Registration: CRD42022293884.

Biofilm ecology associated with dental caries: Understanding of microbial interactions in oral communities leads to development of therapeutic strategies targeting cariogenic biofilms

A biofilm is a sessile community characterized by cells attached to the surface and organized into a complex structural arrangement. Dental caries is a biofilm-dependent oral disease caused by infection with cariogenic pathogens, such as Streptococcus mutans, and associated with frequent exposure to a sugar-rich diet and poor oral hygiene. The virulence of cariogenic biofilms is often associated with the spatial organization of S. mutans enmeshed with exopolysaccharides on tooth surfaces. However, in the oral cavity, S. mutans does not act alone, and several other microbes contribute to cariogenic biofilm formation. Microbial communities in cariogenic biofilms are spatially organized into complex structural arrangements of various microbes and extracellular matrices. The balance of microbiota diversity with reduced diversity and a high proportion of acidogenic-aciduric microbiota within the biofilm is closely related to the disease state. Understanding the characteristics of polymicrobial biofilms and the association of microbial interactions within the biofilm (e.g., symbiosis, cooperation, and competition) in terms of their potential role in the pathogenesis of oral disease would help develop new strategies for interventions in virulent biofilm formation.