Local and systemic mechanisms linking periodontal disease and inflammatory comorbidities

Unraveling brain aging through the lens of oral microbiota

The oral cavity is a complex physiological community encompassing a wide range of microorganisms. Dysbiosis of oral microbiota can lead to various oral infectious diseases, such as periodontitis and tooth decay, and even affect systemic health, including brain aging and neurodegenerative diseases. Recent studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration, indicating potential avenues for intervention strategies. In this review, we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases, and dissect potential mechanisms by which oral microbes contribute to brain aging and neurodegeneration. We also highlight advances in therapeutic development grounded in the realm of oral microbes, with the goal of advancing brain health and promoting healthy aging.

Association between oral microbiome and depression: A population-based study

OBJECTIVE

Depression is a global mental health issue, particularly affecting adolescents and young adults. While the role of gut microbiota in depression has been extensively studied, the influence of the oral microbiome remains underexplored. Recent studies suggest that the oral microbiome may affect systemic and brain health through the oral-brain axis. This study aimed to investigate the relationship between oral microbiome diversity and depression using data from 6212 participants in the National Health and Nutrition Examination Survey (NHANES) 2009-2012.

METHODS

Oral microbiome diversity was assessed through oral rinse samples using 16S rRNA sequencing, focusing on α-diversity metrics (observed ASVs and Faith's phylogenetic diversity) and β-diversity measures. Depressive symptoms were evaluated with the Patient Health Questionnaire (PHQ-9). Weighted logistic regression models were employed to assess associations between α-diversity and depression, while linear regression was used to examine the relationship between α-diversity and PHQ-9 scores. β-diversity differences were analyzed via permutational analysis of variance (PERMANOVA).

RESULTS

10.03% of the participants were diagnosed with depression. Higher α-diversity in the oral microbiome was negatively correlated with depression: observed ASVs (OR: 0.713 [CI: 0.508-0.999], P = 0.050) and Faith's phylogenetic diversity (OR: 0.584 [CI: 0.367-0.931], P = 0.025). Linear regression indicated that greater α-diversity was associated with lower PHQ-9 scores, reflecting fewer depressive symptoms. Furthermore, β-diversity analysis revealed significant differences in the microbiome composition between depressed and non-depressed individuals.

CONCLUSION

Reduced oral microbiome diversity is associated with an increased risk and severity of depression. The study underscores the importance of exploring the oral-brain axis and highlights the need for further research into the mechanisms and therapeutic strategies targeting this relationship.

Type I interferon protects against bone loss in periodontitis by mitigating an interleukin (IL)-17-neutrophil axis

Type I interferons (IFNs-I), a group of pleiotropic cytokines, critically modulate host response in various inflammatory diseases. However, the role of the IFN-I pathway in periodontitis remains largely unknown. In this report, we describe that the IFN-β levels in the gingival crevicular fluid of human subjects were negatively associated with periodontitis and clinical gingival inflammation. Disruption of IFN-I signaling worsened alveolar bone resorption in a ligature-induced periodontitis murine model. Deficiency of the IFN-I pathway resulted in an exaggerated inflammatory response in myeloid cells and drastically increased the interleukin-17 (IL-17)-mediated neutrophil recruitment in the gingiva. We further identified that the myeloid lineage-specific IFN-I response was essential in safeguarding against periodontal inflammation by suppressing the IL-17-producing γδ T cells in gingiva. IFN-I signaling also directly repressed osteoclastogenesis in monocytes, which are precursor cells for osteoclasts. Therefore, our findings demonstrate that an integral myeloid-specific IFN-I pathway protects against bone loss by keeping the IL-17-neutrophil axis in check and directly inhibiting osteoclast formation in periodontitis.

Microenvironment-sensitive hydrogels as promising drug delivery systems for co-encapsulating microbial homeostasis probiotics and anti-inflammatory drugs to treat periodontitis

Developing and utilizing effective local antimicrobial agents can help treat periodontitis while minimizing the risks associated with systemic antibiotic use. Recent studies have shown that the mucosal adhesion properties of hydrogels can play a potential role in the treatment of periodontitis. The hydrogel can improve the contact and retention time of drugs in the periodontal pocket. Through the adhesion of mucosa, it interacts with the mucin coating surface of epithelium and teeth to form a specific interface force. The hydrogel exhibits strong mucosal adhesion (adhesion strength: 5-6 N/cm2) and prolonged retention in periodontal pockets (≥6 h), enabling sustained drug release through dynamic sol-gel transitions triggered by pH and reactive oxygen species (ROS). This design overcomes the limitations of poor mechanical stability in conventional formulations. The dynamic balance of oral microbiota plays an important role in maintaining oral health. Probiotics, by colonizing the oral cavity, transform the infected site from an environment rich in inflammatory cytokines to a more benign environment, inhibit harmful pathogenic microorganisms, and contribute to overall health. Microenvironment sensitive hydrogels can perform dynamic sol gel transformation in situ, and can accurately control drug release when exposed to various stimuli (such as temperature change, light, pH change, reactive oxygen species, etc.). Oral probiotics and anti-inflammatory drugs are encapsulated in hydrogels to inhibit the proliferation and adhesion of oral pathogens by planting in the mouth and producing metabolites, effectively preventing and treating oral diseases.

ENTR1 regulates periodontitis by modulating macrophage M1 polarization via AMPK activation

AIMS

Periodontitis is a chronic inflammatory disorder arising from an imbalance between oral microbiota and the host's immune response, with macrophages as pivotal targets for prevention and treatment. Endosome-associated Trafficking Regulator 1 (ENTR1) is indispensable for protein trafficking and implant osseointegration. However, its specific role in periodontitis has yet to be clarified. This research seeks to explore the effects of ENTR1 on macrophage polarization, elucidate its mechanisms, and evaluate its regulatory functions in the regeneration of periodontal tissues.

MATERIALS AND METHODS

A ligature-induced periodontitis mouse model was established to investigate the correlation between macrophage polarization markers and ENTR1 expression. Techniques including qRT-PCR, Western blot, ELISA, flow cytometry, and immunofluorescence staining were utilized to evaluate the impact of ENTR1 on macrophage polarization under inflammatory stimuli. Micro-CT and histological staining were applied to assess periodontal bone resorption. The interaction between ENTR1 and AMP-activated protein kinase (AMPK) was explored through Western blot and co-immunoprecipitation, further validated by applying the AMPK inhibitor Compound C (CpC).

KEY FINDINGS

ENTR1 expression was down-regulated in the mice with periodontitis relative to healthy controls. Overexpressing ENTR1 suppressed macrophage M1 polarization and mitigated bone loss in periodontitis, while knocking down ENTR1 exacerbated these effects. ENTR1 directly interacted with AMPK, enhancing its phosphorylation. Furthermore, the inhibitory impact of ENTR1 on macrophage M1 polarization and inflammation-induced alveolar bone resorption were partially attenuated by CpC treatment.

SIGNIFICANCE

ENTR1 regulates periodontitis by suppressing macrophage M1 polarization through enhancing AMPK phosphorylation, presenting a promising therapeutic target for its prevention and management.

Associations between the oral microbiome, number of teeth and frailty among American adults: A cross-sectional study from NHANES 2009-2012

BACKGROUND

The intricate interrelationship between oral health, the number of teeth, oral microbiota, and frailty remains largely unexplored in clinical research. This study aimed to investigate the interrelationship between oral microbiome, the number of teeth, and frailty.

METHODS

Data from 4518 participants in NHANES 2009-2012 were analyzed. Frailty was measured using the 48-item Frailty Index (FI). Multivariable logistic regression and restricted cubic spline (RCS) evaluated associations between alpha diversity and frailty. Mediation analysis was used to assess the role of number of teeth. The associations between oral microbiome diveristy and mortality were analyzed by Cox regression. Beta diversity was examined with PCoA and PERMANOVA.

RESULTS

The prevalence of frailty was 39.73 %. Univariate analysis showed that alpha diversity indices except for the Simpson index were significantly lower in frailty, and after adjusted for confounders, observed ASVs (adjusted OR: 0.80 [0.73, 0.87], p < 0.001), Faith's PD (adjusted OR: 0.81 [0.74, 0.88], p < 0.001) and Shannon-Weiner index (adjusted OR: 0.88 [0.81, 0.95], p = 0.002) were remained significantly associated with frailty. The reduced number of teeth partially mediated the relationship (for Faith's PD: βindirect = -0.001 [-0.003, 0.000], p = 0.036, proportion: 8.33 % [0.00 %, 37.50 %]; for Shannon-Weiner index, βindirect = -0.007 [-0.013, -0.002], p = 0.007, Proportion = 17.07 % [3.39 %, 65.00 %]). Univariable Cox proportional hazard regression showed that all alpha diversity indices were significantly associated with all-cause mortality in frail population, and in multivariable analysis, Shannon-Weiner index (HR: 0.72 [0.55, 0.94], p = 0.017) and Simpson index (HR: 0.71 [0.60, 0.83], p < 0.001) remained statistically significant. PCoA showed that beta diversity was also significantly associated with frailty.

CONCLUSION

Lower oral microbiome diversity is associated with higher frailty and mortality. The number of teeth partially mediates this link, emphasizing the importance of oral health in mitigating frailty and promoting healthy aging.

The Relationship of HbA1c Serum Levels with the Severity of Periodontal Disease in Patients with Type 1 Diabetes Mellitus: A Cross-Sectional Study

OBJECTIVE

 According to the evidence, the level of glycemic control is of key importance in determining the increased risk of periodontal disease (PD). The aim of the study was to evaluate the role of metabolic control as a key factor leading to the development and severity of periodontitis and compare the periodontal and oral hygiene status with the glycated hemoglobin levels.

MATERIALS AND METHODS

 The evaluation was undertaken with diabetic patients (59 uncontrolled diabetics and 36 controlled diabetics) from a patient cohort of the Hospitalar Center of Tâmega e Sousa and subjects without diabetes (n = 95).

STATISTICAL ANALYSIS

 The data were analyzed using IBM SPSS Statistics software (Statistical Program for Social Sciences), version 29.0 for Windows. In the logistic regression analysis, odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. The significance level was set at 0.05.

RESULTS

 Periodontal parameters were increased in systemically compromised individuals especially those who were poorly controlled as compared with their healthy counterparts, which are important indicators of PD progression. Furthermore, uncontrolled type 1 diabetic mellitus (T1DM) patients showed increased plaque index (PI), which predisposes these individuals to a greater degree of periodontal destruction and tooth loss. Using a binary logistic regression, we observe a significant relation of the risk of severe periodontitis in T1DM subjects with family history of T1DM (p = 0.019; OR: 3.36; 95% CI: 1.22-9.21), alcohol consumption (p = 0.02; OR: 3.78; 95% CI: 1.23-11.63), periodontal probing depth (PPD) (p < 0.001; OR: 3.64; 95% CI: 14.74-90.34), and clinical attachment loss (p = 0.033; OR: 4.71; 95% CI: 1.13-19.59).

CONCLUSION

 Increased glycated hemoglobin levels were positively related with periodontal status. Uncontrolled systemically compromised individuals showed an increased Plaque index (PI), which predisposes to greater periodontal inflammation and tooth loss. Increased clinical attachment level, Periodontal probing depth (PPD) and family history of T1DM, and alcohol consumption were identified as potential risk factors for severe periodontitis in subjects with T1DM.

A nucleoside-based supramolecular hydrogel integrating localized self-delivery and immunomodulation for periodontitis treatment

Periodontitis is a highly prevalent oral disease characterized by bacterial-induced hyperactivation of the host immune system, leading to a sustained inflammatory response and osteoclastic activity, which ultimately results in periodontal destruction. In this work, an immunomodulatory supramolecular hydrogel for the topical treatment of periodontitis was synthesized using a simple one-pot method. This phenylboronate ester-based 8AGPB hydrogel exhibited excellent stability, self-healing properties, injectability, and biocompatibility. During degradation, the 8AGPB hydrogel releases immunomodulatory agent 8-aminoguanosine (8AG), which regulates MAPK and NF-κB signaling pathways by modulation of second messengers in macrophages. In combination with 1,4-phenylenediboronic acid (PBA), which possesses antioxidant properties, 8AG effectively inhibits ROS production and oxidative damage in LPS-stimulated macrophages, lowering the M1/M2 macrophage polarization ratio and reducing the secretion of pro-inflammatory factors. In an experimental periodontitis model using C57BL/6 mice, periodontal injection of the 8AGPB hydrogel reduced inflammatory infiltration and osteoclastic activity through immunomodulation and inhibition of osteoclast differentiation, thereby ameliorating periodontal destruction during periodontitis progression. Overall, the 8AGPB supramolecular hydrogel, serving as an injectable self-delivery platform for 8AG, may represent a promising novel strategy for periodontitis treatment and offer insights for the development of future topical anti-inflammatory systems.

M2 Macrophage-Derived Extracellular Vesicles Reprogram Immature Neutrophils into Anxa1hi Neutrophils to Enhance Inflamed Bone Regeneration

Periodontitis is a microbiome-related inflammation that can lead to irreversible bone reduction and even tooth loss. This study reveals that macrophage polarization states significantly influence periodontal homeostasis, with M2 macrophage-derived extracellular vesicles (M2-EVs) playing a pivotal role in mitigating periodontitis-induced bone loss. Single-cell RNA sequencing of periodontal tissues treated with M2-EVs uncovered a unique Anxa1hi neutrophil subpopulation exhibiting pro-reparative properties. This subpopulation is characterized by immaturity and demonstrated osteogenic and angiogenic capabilities in vivo, partially mediated through the secretion of oncostatin M (OSM) signals. The findings suggest that this functional heterogeneity arises from M2-EVs disrupting the neutrophil maturation trajectory, with pivotal reprogramming genes, such as Acvrl1 and Fpr2, driving the differentiation of the Anxa1hi reparative subpopulation. This work underscores the potential of targeting M2 macrophage-neutrophil interactions to promote the regeneration of inflamed bone tissues.

The influence of periodontal disease and periodontal treatment on colorectal cancer

BACKGROUND

Periodontal disease (PD) is associated with more than 50 diseases and conditions, including colorectal cancer. The study aimed to investigate if periodontal treatment influences the blood levels of C-reactive protein (CRP) in colorectal cancer patients. In addition, the aim was to isolate periodontal pathogenic bacteria Fusobacterium nucleatum (FN) and Porphyromonas gingivalis (PG), which are most linked to colorectal cancer (CRC), from the mucosa of the cancer-affected intestine.

PATIENTS AND METHODS

To assess the effect of periodontal treatment on colorectal cancer, we measured the CRP levels in the blood during cancer therapy on the day of the initial examination by the oncological surgeon, two days following surgery, and at the first follow-up appointment. We compared the CRP levels between two groups: the group of subjects who underwent periodontal treatment and the patients who did not receive periodontal disease treatment. An attempt was made to isolate the periodontal pathogenic bacteria FN and PG from the mucosa of the cancerous tissue in the colon by using quantitative culture.

RESULTS

We found no statistically significant difference between the groups in the initial CRP measurements before starting cancer treatment. There was no statistically significant difference between the groups in the CRP measurements taken 1st and 2nd day after surgery and at the follow-up appointment. We could not isolate periodontal pathogenic bacteria FN and PG from cancer-altered intestine mucosa using the quantitative culture method.

CONCLUSIONS

Our study did not find any correlation between periodontal treatment and CRC.

Mitochondrial dysfunction as a key player in aggravating periodontitis among diabetic patients: review of the current scope of knowledge

Periodontitis is a prevalent inflammatory disease that leads to significant periodontal tissue destruction and compromised dental health, with its severity exacerbated in individuals with Diabetes Mellitus (DM). This review explores the complex relationship between mitochondrial dysfunction and periodontitis in diabetic patients. Recent studies indicate that the excessive production of reactive oxygen species (ROS), primarily generated by dysfunctional mitochondrial electron transport chain (ETC) complexes, contributes to oxidative stress (OS) and subsequent periodontal tissue damage. The interplay between impaired mitochondrial biogenesis, apoptosis of periodontal cells, and ROS accumulation highlights a critical area of concern in understanding the pathophysiology of diabetic periodontitis. Furthermore, altered glycemic control due to inflammatory processes associated with periodontitis may perpetuate a cyclical detriment to oral and systemic health. This review aims to highlight the mechanistic roles of mitochondrial dysfunction in the aggravation of periodontitis among diabetic patients, emphasizing further research to identify potential therapeutic targets and improve treatment efficacy for this dual pathology.

Biodegradable Piezoelectric Janus Membrane Enabling Dual Antibacterial and Osteogenic Functions for Periodontitis Therapy

Guided tissue regeneration (GTR) using barrier membranes is a common clinical approach for treating periodontitis-induced alveolar bone loss. However, conventional GTR membranes lack antibacterial and osteoinductive properties, limiting their effectiveness. Piezoelectric materials, which generate electrical outputs under chewing forces, offer antibacterial and bone-regenerative potential due to their oppositely charged surfaces. Inspired by this, a piezoelectric Janus membrane was developed for dual-function GTR therapy. Biodegradable poly(l-lactide) (PLLA) and PLLA/gelatin membranes were electrospun, annealed, and polarized to create the A-P(+)/PG(-) piezoelectric Janus membrane. Notably, in this Janus membrane, the outer surface of the PLLA side (A-P(+)) carries positive charges and is positioned toward the gingival tissue to kill bacteria via charge interactions; the inner surface of the PG side (PG(-)) holds negative charges and faces the alveolar bone defect, promoting bone growth through immunomodulation and enhanced mineralization. In a mouse model of periodontitis, the Janus membrane A-P(+)/PG(-) demonstrated dual functionality, effectively reducing inflammation, inhibiting bone resorption. The bone mineral density of A-P(+)/PG(-) reached 1637 ± 37 mg/cm3 at 8 weeks after surgery, which was superior to commercial collagen membranes lacking antibacterial properties. Overall, this study introduces an innovative approach, leveraging biodegradable piezoelectric PLLA to construct a versatile Janus GTR membrane with enhanced antibacterial and osteogenic activity for periodontitis treatment.

Recent advances in therapeutic probiotics: insights from human trials

SUMMARYRecent advances in therapeutic probiotics have shown promising results across various health conditions, reflecting a growing understanding of the human microbiome's role in health and disease. However, comprehensive reviews integrating the diverse therapeutic effects of probiotics in human subjects have been limited. By analyzing randomized controlled trials (RCTs) and meta-analyses, this review provides a comprehensive overview of key developments in probiotic interventions targeting gut, liver, skin, vaginal, mental, and oral health. Emerging evidence supports the efficacy of specific probiotic strains and combinations in treating a wide range of disorders, from gastrointestinal (GI) and liver diseases to dermatological conditions, bacterial vaginosis, mental disorders, and oral diseases. We discuss the expanding understanding of microbiome-organ connections underlying probiotic mechanisms of action. While many clinical trials demonstrate significant benefits, we acknowledge areas requiring further large-scale studies to establish definitive efficacy and optimal treatment protocols. The review addresses challenges in standardizing probiotic research methodologies and emphasizes the importance of considering individual variations in microbiome composition and host genetics. Additionally, we explore emerging concepts such as the oral-gut-brain axis and future directions, including high-resolution microbiome profiling, host-microbe interaction studies, organoid models, and artificial intelligence applications in probiotic research. Overall, this review offers a comprehensive update on the current state of therapeutic probiotics across multiple domains of human health, providing insights into future directions and the potential for probiotics to revolutionize preventive and therapeutic medicine.

Comparative analysis of oral health behaviour and utilisation of oral health care services in the general population and among patients with non-communicable diseases in Korea: a repeated cross-sectional survey conducted from 2008 to 2022

BACKGROUND

Understanding the oral health behaviour and utilisation of oral health care services among patients with non-communicable diseases (NCDs) is essential for the development of oral health care management services for these patients. In this study, we comparatively analysed the trends in oral health behaviour and oral health care service utilisation among patients with various NCDs and the general population.

METHODS

We analysed data obtained via the Korea Community Health Survey from 2008 to 2022. Comparative analyses of the general population and patients with 15 different NCDs, including diabetes mellitus and depression, were conducted for the following variables: toothbrushing practice, use of dental floss and interdental brushes, annual scaling (tartar removal), and annual oral examinations. Joinpoint regression analyses were used to assess for statistically significant changes in oral health behaviour and oral health care service utilisation according to year and region.

RESULTS

Overall, oral health behaviour steadily improved in the general population and among patients with NCDs. However, the rates of toothbrushing before going to bed in patients with hypertension (90.0%) and diabetes mellitus (88.7%) were still lower than that in the general population (92.9%) in 2022. Regarding oral health service utilisation, the rates of annual scaling and oral examination among patients with NCDs, apart from those with dyslipidaemia, were lower than those in the general population. For example, in 2017, the rates of annual scaling and oral examination of patients with diabetes mellitus were 43.4% and 36.5%, respectively. These rates were lower than those in the general population, at 47.2% and 43.0%, respectively. In terms of inter-regional variations in oral health-related indicators, considerable inter-regional variations were observed in the oral health behaviour and oral health care service utilisation of patients with NCDs.

CONCLUSION

This study highlighted that the practice and utilisation rates of oral health behaviour and oral health care services, respectively, among patients with NCDs have increased. However, in comparison with those of the general population, further improvements are necessary. A practical solution could be to establish a system that provides all necessary oral-related services, such as patient education and oral examinations, to NCDs patients through medical-dental integration or oral medical care coordination.

Bidirectional Interaction Between Chronic Kidney Disease and Porphyromonas gingivalis Infection Drives Inflammation and Immune Dysfunction

Introduction: Chronic kidney disease (CKD) is characterized by a decline in renal function, increased mortality, and significant impairments in the immune system and function of immune cells. These alterations are often derived by uremic toxins, which, in turn, modify the immune system's response to infections. Our research investigates the progression of Porphyromonas gingivalis (P. gingivalis) infection during CKD and its subsequent impact on kidney failure. Methods: We utilized two infectious models, a chamber model representing short-term local inflammation and alveolar bone loss that mimic chronic infection of periodontium, both in conjunction with a CKD model. Additionally, our in vitro studies employed primary macrophages, osteoclasts, and lymphocytes to characterize the immune responses to P. gingivalis and pathogen-associated molecular patterns (PAMPs) in the presence of uremic toxins. Results and Conclusion: Our findings demonstrate that uremic toxins, such as indoxyl sulfate (IS), alter responses of macrophages and lymphocytes to P. gingivalis. In vivo, CKD significantly enhanced P. gingivalis survival and infection-induced alveolar bone loss. The increased distribution of pathogen within peripheral tissues was associated with altered inflammatory responses, indicating that CKD promotes infection. Moreover, P. gingivalis-infected mice exhibited a marked increase in renal inflammation, suggesting that the relationship between uremia and infection is bidirectional, with infection exacerbating kidney dysfunction. Furthermore, we observed that infected CKD mice exhibit decreased serum immunoglobulin G (IgG) levels compared to infected mice without CKD, implying that uremia is associated with immune dysfunction characterized by immunodepression and impaired B lymphocyte function.

Impact of periodontitis on oral microbiota in pregnant women with gestational diabetes mellitus: A case-control study

OBJECTIVES

This study aims to explore the distribution characteristics of oral microbiota in pregnant women with gestational diabetes mellitus (GDM) and its association with periodontitis.

METHODS

This case-control study included 80 GDM women, divided into the periodontitis group (PD group, n = 40) and the periodontally healthy group (N group, n = 40). Unstimulated saliva samples were collected for 16S rRNA sequencing targeting the V3∼V4 region. We used α-diversity and β-diversity to assess the richness and diversity of the oral microbiota and the variability between groups. The Mann-Whitney U test and linear discriminant analysis effect size (LEfSe) analysis were used to identify significant differences in microbial composition and to evaluate categorical differences between groups.

RESULTS

Significant differences in α-diversity and β-diversity were observed between the PD group and the N group. The PD group exhibited a higher abundance of Bacteroidota, Fusobacteriota, Spirochaetota, Synergistota, and Choroflexi compared to the N group. LEfSe analysis identified Spirochaetora and Tetraptera as the taxonomic biomarkers in the PD group. Furthermore, activating environmental adaptation, terpenoid and polyketide metabolism, and the immune and endocrine systems pathways may be involved in the potential mechanisms of the PD group.

CONCLUSIONS

A significant correlation was observed between oral microbiota composition and periodontitis in pregnant women with GDM. Spirochaetota and Tetraptera are closely linked to the progression of periodontitis and may serve as biomarkers for early diagnosis. Targeting these microbial taxa could provide new strategies for preventing and managing periodontitis during pregnancy, potentially reducing adverse maternal and fetal outcomes.

Microbiome composition and metabolic pathways in shallow and deep periodontal pockets

In periodontal diseases, a dysbiotic subgingival microbiome interacts complexly with the host immune response and is strongly considered a risk factor for various systemic conditions. The high prevalence of both periodontal and systemic diseases in older adults highlights the importance of characterizing the subgingival microbiome in this age group. This study specifically characterizes the composition of the subgingival microbiome and investigates the interactions between microbial niches in shallow and deep periodontal pockets in individuals in their early 70s. We collected 1928 samples from 1287 participants, all born between 1950 and 1951. Participants had either shallow (≤ 4 mm) periodontal pockets or both shallow and deep (≥ 5 mm) periodontal pockets. Distinct microbial patterns were observed in shallow and deep periodontal pockets within the same oral cavity. Deep pockets exhibited a significantly higher abundance of species from genera such as Prevotella, Centipeda, Treponema, and Fusobacterium, while shallow pockets were enriched with species from Actinomyces, Pauljensenia, Streptococcus, and Gemella. The top significant species associated with deep pockets included Fretibacterium fastidiosum, Tannerella forsythia, and Treponema denticola, whereas shallow pockets were predominantly associated with Actinomyces species and Rothia dentocariosa. Additionally, shallow pockets in individuals with both pocket types showed a positive association with Tannerella forsythia, Porphyromonas gingivalis, and Fusobacterium nucleatum compared to shallow pockets in individuals with only shallow pockets. Metabolic pathways showed significant variation with pocket depth, with pathways such as lipopolysaccharide metabolism, lipid metabolism, and polyamine biosynthesis being positively associated with deep pockets. Overall, this study provides comprehensive microbiome analyses of periodontal pockets in aging adults, contributing to a better understanding of periodontal health and its potential impact on reducing systemic health risks in aging populations.

Hematopoietic stem cell state and fate in trained immunity

Trained immunity serves as a de facto memory for innate immune responses, resulting in long-term functional reprogramming of innate immune cells. It enhances resistance to pathogens and augments immunosurveillance under physiological conditions. Given that innate immune cells typically have a short lifespan and do not divide, persistent innate immune memory may be mediated by epigenetic and metabolic changes in long-lived hematopoietic stem cells (HSCs) in the bone marrow. HSCs fine-tune their state and fate in various training conditions, thereby generating functionally adapted progeny cells that orchestrate innate immune plasticity. Notably, both beneficial and maladaptive trained immunity processes can comprehensively influence HSC state and fate, leading to divergent hematopoiesis and immune outcomes. However, the underlying mechanisms are still not fully understood. In this review, we summarize recent advances regarding HSC state and fate in the context of trained immunity. By elucidating the stem cell-intrinsic and extrinsic regulatory network, we aim to refine current models of innate immune memory and provide actionable insights for developing targeted therapies against infectious diseases and chronic inflammation. Furthermore, we propose a conceptual framework for engineering precision-trained immunity through HSC-targeted interventions.

Engineered Macrophage Membrane-Camouflaged Nanodecoys Reshape the Infectious Microenvironment for Efficient Periodontitis Treatment

A vicious cycle between microbiota dysbiosis and hyperactivated inflammation, hardly disrupted by conventional therapies, remains a significant clinical challenge for periodontitis treatment. Herein, by cloaking a cascade catalysis system in an engineered macrophage membrane, a nanodecoy-based strategy, with targeted bacteria-killing and immunomodulatory abilities, is proposed for reshaping the hostile periodontitis microenvironment. Specifically, recombinant human antimicrobial peptide, LL-37, is anchored to a Toll-like receptor-enriched macrophage membrane via genetic engineering, which facilitates the specific bacteria elimination and efficient tissue retention of the nanodecoys. Moreover, the cascade catalysis system integrates L-amino acid oxidase (LAAO) with hollowed manganese dioxide (hMnO2) by reciprocal elevation of the catalytic efficiency of hMnO2 and LAAO, leading to accelerated O2 generation under a hypoxic microenvironment and disrupted metabolism of periodontopathogenic bacteria. Notably, the nanodecoys trigger the nuclear translocation of NF-E2-related factor-2 (NRF2) to reduce oxidative stress response and rewire the polarization of macrophages, thereby boosting the osteogenic differentiation of osteoblasts. Furthermore, the alveolar bone regeneration therapeutically benefits from the nanodecoys in vivo. Altogether, these results highlight the attractive functions of engineered macrophage membrane-cloaked nanodecoys for effective periodontitis treatment.

Comparative analysis of immune markers in multiple sclerosis and rheumatoid arthritis patients with oral disease

INTRODUCTION

A substantial body of research has underscored the intricate nature of diagnosing oral disorders in conjunction with chronic inflammatory diseases.

Oral health behaviours and metabolic syndrome: mediation effect of lifestyle habits

BACKGROUND

Recent studies have reported an association between toothbrushing frequency and systemic health. Plaque control, achieved through frequent brushing, is known to prevent dental caries and periodontal disease, potentially reducing the risk of systemic diseases. However, individuals with good oral health behaviours may also exhibit healthier lifestyle habits which could impact systemic health. In examining the relationship between oral health behaviours and systemic health, it is important to consider the influence of factors that mediate the relationship between them. This study conducted mediation analyses to evaluate the extent to which lifestyle habits and periodontal status mediate the relationship between oral health behaviours and systemic health.

METHODS

Health examinations, including dental assessments, were performed on 15,579 individuals at the Aichi Health Promotion Foundation. Of these, 12,540 participants aged 40-74 years were included in the analysis. Mediation analyses were conducted using the number of metabolic syndrome (MS) components as the outcome variable, oral health behaviours (regular dental visits, use of interdental brushes or dental floss, and toothbrushing frequency) as exposure variables, lifestyle habits (smoking, drinking, exercise, and eating habits) and periodontal status as mediators, and age and sex as covariates.

RESULTS

Regular dental visits showed significant total and indirect effects on MS, although no significant direct effect was observed. The use of interdental brushes or dental floss and toothbrushing frequency demonstrated significant total, direct and indirect effects on MS. Exercise habits, eating habits and periodontal status were significant mediators in the relationship between regular dental visits and MS. These mediators also significantly influenced the associations between both the use of interdental brushes or dental floss and toothbrushing frequency with MS.

CONCLUSION

The relationship between oral health behaviours and MS is mediated by lifestyle habits and periodontal status. Among the mediating variables tested in this study, the indirect effects of diet and exercise habits tended to be stronger than the indirect effect of periodontal disease. Oral health behaviours may influence systemic health through their impact on lifestyle habits.

Influence of antidepressant use on periodontal status: a systematic review and meta-analysis

OBJECTIVE

The aim of this review was to evaluate the influence of antidepressant use on inflammatory and clinical data related to periodontal status in animal and human studies.

MATERIALS AND METHODS

A systematic review was conducted according to the PRISMA guidelines. The potential risk of bias was assessed using the SYRCLE RoB or the Joanna Briggs Institute tools. For human studies, a meta-analysis was performed to compare periodontal parameters between users and non-users of antidepressants, and to estimate the mean difference using random effects models.

RESULTS

Twelve studies met the inclusion criteria: eight were conducted on animal models, and four were human studies. Tianeptine, desipramine, imipramine, and fluoxetine effectively reduced alveolar bone loss in experimental periodontitis. Furthermore, desipramine, imipramine, and fluoxetine were observed to reduce the expressions of inflammatory markers in gingival tissue. The meta-analysis found no differences in the influence of antidepressant use on periodontal pocket depth, clinical attachment level, and gingival index between users and non-users. There was no standardization of the duration of use, type, and dosage of medication between studies.

CONCLUSIONS

Animal studies suggest antidepressants modulate the immunoinflammatory response and prevent alveolar bone loss in experimental periodontitis, but their impact on human periodontal status remains controversial. Standardized methods are needed to clarify antidepressant effects on the periodontium.

CLINICAL RELEVANCE

This study informs health professionals that certain antidepressants may positively impact the periodontium, while also highlighting the need for further research evaluating their possible influence on the human periodontal condition and their potentially associated local/systemic adverse effects.

Interfacial Engineering Enhancing Electron Transfer of CaF2 Nanoparticles for Periodontitis Treatment of Sonotherapy and Bone Resorption

Conventional periodontitis treatments can be superseded by sonodynamic therapy. In this study, a Zn(OH)F/CaF2 heterojunction was synthesized via a hydrothermal method, which exhibited good biocompatibility and antibacterial properties. The band gap decreased significantly after the formation of the heterojunction, thereby enhancing the internal electron transfer. In addition, after the bacteria contact with the material, the electrons of the electron transport chain turn to Zn(OH)F/CaF2 and affect its steady state. Ultimately, H2O2 in an inflammatory environment was used to react with Zn(OH)F/CaF2 to facilitate electron transfer under the influence of ultrasound, ultimately enhancing the catalytic activity. Zn(OH)F/CaF2 exhibits significant antibacterial efficacy against Porphyromonas gingivalis and Staphylococcus aureus. Trace elements Ca and Zn can promote tissue repair and osteogenic differentiation, resulting in less bone destruction and intact gingival tissue after periodontitis treatment. This sonodynamic therapy provides a rapid antibacterial, effective, and deep therapeutic method for treating periodontitis.

A Systematic Review and Meta-Analysis Association Between Periodontitis and Age-Related Macular Degeneration: Potential for Personalized Approach

Background/Objectives: Periodontitis is a chronic inflammatory disease that leads to systemic low-grade inflammation. Systemic low-grade inflammation has been found in patients with age-related macular degeneration (AMD). In this systematic review and meta-analysis, we evaluated the association between periodontitis and AMD. Methods: We searched 11 scientific literature databases on 16th December 2024 for studies of a diagnosis of periodontitis and prevalent or incident AMD. Eligible studies underwent a qualitative review and meta-analysis of the association. Study selection, data extraction, and risk of bias within studies were made in duplicate by two authors and conferred with a senior author. Results: Seven studies eligible for review included in total 149,217 individuals. Across the seven studies, different study designs, diagnoses and definitions of periodontitis, and diagnosis and definitions of AMD were employed. Our meta-analysis showed an association between periodontitis and AMD with an odds ratio of 1.42 (95% CI: 1.12 to 1.78; p = 0.003). Conclusions: Periodontitis is significantly associated with AMD. Unlike genetic predisposition and high age, which are important risk factors of AMD that cannot be modified, periodontitis is a risk factor that can be treated and potentially eliminated, thus allowing for a personalized approach for risk elimination in AMD. Attention should be given to the dental health of patients at risk of AMD.

Porphyromonas gingivalis-OMVs promote the epithelial-mesenchymal transition of oral squamous cell carcinoma by inhibiting ferroptosis through the NF-κB pathway

Background

Recent studies reported the role of Porphyromonas gingivalis (P. g) in promoting oral squamous cell carcinoma (OSCC) progression. However, the molecular mechanism remains unclear.

Materials and methods

P. g-OMVs were isolated using ultracentrifugation method and characterized by transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA). CCK-8, migration, invasion, Quantitative real-time Polymerase Chain Reaction (qRT-PCR) and immunocytochemistry assays were performed to evaluate the effect of P. g-OMVs on tumor cells' proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), and ferroptosis in vitro. Western blot was performed to study the phosphorylation of transcription factor nuclear factor kappa B (NF-κB). In vivo, the effect of P. g-OMVs on the growth of OSCC was evaluated using a xenograft tumor model, followed by hematoxylin and eosin and immunohistochemistry staining.

Results

TEM and NTA demonstrated that P. g-OMVs have a vesicular structure with a particle size of around 118 nm. Compared to the control group, P. g-OMVs significantly enhance the proliferation, migration, and invasion of tumor cells. In addition, P. g-OMVs promote the EMT of OSCC cells, which can be attenuated by ferroptosis activator erastin. Moreover, P. g-OMVs inhibit feroptosis of OSCC by activating NF-κB signaling. In vivo, P. g-OMVs significantly enhance tumor growth of OSCC. Inhibition of NF-κB could significnatly reduce the growth of OSCC, which can be further rescued using ferroptosis inhibitor Ferrostain-1.

Conclusions

P. g-OMVs promote OSCC progression by modulating the ferroptosis-related EMT through NF-κB signaling.

Poly-T-Modified Gold Nanorods Suppress Macrophage-Mediated Inflammation for Periodontitis Therapy

Traditional treatments for periodontitis are limited by their inability to adequately modulate the immune response and control inflammation. Recently, nucleic acid-modified nanomaterials have attracted significant attention for their potential in regulating inflammation. Among these, most nanomaterials, such as spherical nucleic acids, tend to exhibit pro-inflammatory effects. In this study, we identified for the first time that poly-T sequence-modified gold nanorods (PTM AuNRs) possess significant anti-inflammatory properties. The PTM AuNRs demonstrated excellent biocompatibility and efficacy in treating ligation-induced periodontitis. PTM AuNRs modulate immune responses by inhibiting the differentiation of pro-inflammatory M1 macrophages and reducing pro-inflammatory cytokine levels through promoting AMPK activation. When administered via local injection, PTM AuNRs effectively suppress inflammatory response and inflammatory cell infiltration, downregulate inflammatory cytokine levels, and mitigate collagen fiber degradation and alveolar bone loss. Together, these findings highlight PTM AuNRs as a promising and innovative therapeutic strategy for periodontitis management.

Study on the Clinical Efficacy of Combined Therapy with Minocycline Hydrochloride Ointment and Tinidazole for Chronic Periodontitis: Retrospective Study

Objective

To analyze the clinical efficacy of combined minocycline hydrochloride and tinidazole therapy for chronic periodontitis (CP).

Methods

A retrospective analysis was conducted on clinical data from 93 CP patients admitted to our hospital from January 2021 to January 2023. All patients met the inclusion and exclusion criteria. They were divided into a control group (n=46) and an observation group (n=47). All patients received full-mouth ultrasonic debridement. On this basis, patients in the control group received weekly subgingival minocycline hydrochloride ointment (Sunstar®) injections, while patients in the observation group received combined 500 mg tinidazole tablets twice daily ×4 weeks. Periodontal parameters and gingival crevicular fluid (GCF) biomarkers were assessed at baseline and 3-month follow-up.

Results

The results showed that the total effective rate of treatment in the observation group (91.49%) was significantly higher than that in the control group (73.91%) (P<0.05). The periodontal indicators (Plaque Index, Gingival Bleeding Index, Periodontal Pocket Depth), inflammatory factor indicators (C-reactive protein, Tumor Necrosis Factor-α, Interleukin-1β), Matrix Metalloproteinase-9 (MMP-9), and Secretory Immunoglobulin A (SIgA) levels of both groups decreased significantly after treatment. Moreover, these indicators in the observation group were significantly lower than those in the control group (P<0.05). There was no significant difference in the incidence of adverse reactions between the two groups (P>0.05).

Conclusion

The combination therapy of minocycline hydrochloride and tinidazole significantly improved the clinical efficacy for CP patients. Compared with minocycline hydrochloride alone, the addition of tinidazole further improved patients' periodontal health, reduced the inflammatory response and MMP-9, SIgA levels, and did not increase the risk of adverse reactions. This suggests good drug safety and clinical promotion value.

Effect of non-surgical treatment in diabetes-associated periodontitis on immune/inflammatory and oxidative stress biomarkers: A pilot study

AIMS

To investigate the effects of non-surgical periodontal treatment on the levels of cytokines, sIgA, antimicrobial peptides, oxidative and antioxidative agents in comparison between patients with and without diabetes.

METHODS

A case-control study that included patients (n = 45) with periodontitis who have or do not have diabetes. Cytokine concentrations in crevicular gingival fluid (GCF) and saliva were determined using LUMINEX and ELISA assays, respectively. Salivary levels of lysozyme, cathelicidin (LL-37), total antioxidant capacity (TAC) and total peroxide were determined colorimetrically before (T0) and one month after completion of periodontitis treatment (T1).

RESULTS

There were no significant differences in the concentrations of cytokines in GCF between the groups and T0 and T1. Salivary concentrations of lysozyme and IL-10 were significantly reduced in T1 compared to T0 in the diabetes group (p = 0.0260 and p = 0.0034, respectively), whilst TNF-α concentration was higher in T1 (p = 0.0443). The salivary concentrations of TNF-α observed in the non-diabetes group at T1 decreased at T0 (p = 0.0313). The salivary concentration of TNF-α was increased in the diabetes group compared to the non-diabetes group at T1 (p = 0.0008).

CONCLUSIONS

An improvement in salivary inflammatory status was observed in the group without diabetes, which was not found in the group with diabetes after non-surgical periodontal treatment.

Public Periodontal Screening Increases Subsequent Regular Dental Visits: The Life Study

INTRODUCTION

A public oral health screening, periodontal disease screening, has been implemented in Japan, but it remains unclear whether screening encourages subsequent regular dental visits. This study aimed to examine whether people who underwent periodontal disease screening were more likely to regularly visit dentists after undergoing the screening than before using a difference-in-differences (DID) approach.

METHODS

This study used health care claims data of municipality residents who underwent periodontal disease screening in 2017 or 2018. For each screening recipient, 4 individuals were extracted from those who did not undergo screening as controls. In the DID analysis, we assessed the change in the proportion of dentist visits at least once every 180 d after undergoing screening.

RESULTS

A total of 4,050 participants were included in the analysis. The proportion of participants visiting dentists was consistent throughout the study period (approximately 45%) among the participants who did not undergo the screening. However, among the participants who underwent the screening, while the proportion who visited dentists was consistent before screening (approximately 60%), the proportion was higher after screening (1-180 d after, 81.2%). DID analysis indicated that the proportion increased by 12.9% after the screening. In addition, the age-subgroup DID estimates were higher in the younger population (aged 20-35 y, 13.9%; 40-55 y, 12.8%; 60 y, 12.6%).

CONCLUSIONS

Among people who underwent periodontal disease screening, a higher proportion visited dentists after undergoing the screening than before, suggesting that periodontal disease screening was associated with an increase in subsequent regular dental visits.Knowledge Transfer Statement:Our results provide evidence that a public oral health screening could increase regular dental visits, which has the potential to improve and maintain people's oral health, especially in the younger population.

New Advances in Periodontal Functional Materials Based on Antibacterial, Anti-Inflammatory, and Tissue Regeneration Strategies

With the global population aging, awareness of oral health is rising. Periodontitis, a widespread bacterial infectious disease, is gaining attention. Current novel biomaterials address key clinical issues like bacterial infection, gum inflammation, tooth loosening, and loss, focusing on antibacterial, anti-inflammatory, and tissue regeneration properties. However, strategies that integrate the advantages of these biomaterials to achieve synergistic therapeutic effects by clearing oral biofilms, inhibiting inflammation activation, and restoring periodontal soft and hard tissue functions remain very limited. Recent studies highlight the link between periodontitis and systemic diseases, underscoring the complexity of the periodontal disease. There is an urgent need to find comprehensive treatment plans that address clinical requirements. Whether by integrating new biomaterials to enhance existing periodontal treatments or by developing novel approaches to replace traditional therapies, these efforts will drive advancements in periodontitis treatment. Therefore, this review compares novel biomaterials with traditional treatments. It highlights the design concepts and mechanisms of these functional materials, focusing on their antibacterial, anti-inflammatory, and tissue regeneration properties, and discusses the importance of developing comprehensive treatment strategies. This review aims to provide guidance for emerging periodontitis research and to promote the development of precise and efficient treatment strategies.

Association of periodontitis and periodontal parameters with migraine and mortality in people with migraine disease: A nationally representative observational study

OBJECTIVE

To investigate the association of periodontitis and clinical periodontal parameters with migraine as well as mortality among people with migraine disease.

BACKGROUND

Periodontitis has been shown to increase the systemic inflammatory burden thereby promoting various systemic health outcomes; however, the evidence regarding the relationship between periodontitis and migraine is scarce.

METHODS

A cross-sectional study was performed, and it included 13,108 participants from the National Health and Nutrition Examination Survey (1999-2004). Weighted logistic regression analysis was used to evaluate the association between periodontitis/clinical periodontal parameters and migraine. Mediation analysis was performed to explore the potential mediating role of inflammatory response. A cohort study including 1909 participants with migraine disease was further conducted to assess the associations between periodontitis/clinical periodontal parameters and mortality from all causes, cardiovascular disease (CVD), and cancer in participants with migraine disease using Cox proportional hazards models. Death outcomes were ascertained by linkage to National Death Index records through December 31, 2018.

RESULTS

Periodontitis was positively associated with migraine (odds ratio [OR] 1.29, 95% confidence interval [CI] 1.01-1.65). Each 1-unit rise in attachment loss and pocket depth was linked to a 17.5% (OR 1.18, 95% CI 1.08-1.29) and 28.1% (OR 1.28, 95% CI 1.08-1.51) increase in migraine risk, respectively. Mediation analyses revealed that leukocyte, monocyte, and lymphocyte counts mediated 17.9%, 7.3%, and 20.1%, respectively, of the association between periodontitis and migraine. During a median follow-up of 17.7 years among 1909 participants with migraine disease, periodontitis was associated with greater all-cause mortality (hazard ratio 1.82, 95% CI 1.25-2.66), but was not significantly associated with mortality from CVD or cancer among participants with migraine disease. Similar association patterns were also observed for attachment loss and pocket depth.

CONCLUSIONS

This study provides evidence that periodontitis and clinical periodontal parameters were significantly associated with migraine as well as all-cause mortality in people with migraine disease. These findings underscore the importance of considering periodontal health in the prevention and management strategies for migraine disease.

Periodontitis and Hepatocellular Carcinoma: A Two-Sample Mendelian Randomisation Study

INTRODUCTION AND AIMS

Observational studies have reported conflicting associations between periodontitis (PD) and hepatocellular carcinoma (HCC). To overcome these limitations, we performed a two-sample Mendelian randomization (MR) analysis to investigate the potential association between PD and HCC.

METHODS

We used summary data from genome-wide association studies (GWASs) of European ancestry, integrating data from chronic/acute periodontitis (CP/AP) samples (n1 = 34,615; n2 = 277,036; n3 = 410,811) and HCC samples (n1 = 456,348; n2 = 475,638). The inverse variance-weighted (IVW) approach represents our primary analysis method, supplemented by MR-Egger regression, weighted median, weighted-mode, and simple-mode methods. Pleiotropy and heterogeneity tests were also performed.

RESULTS

IVW analysis suggested that PD had no effect on HCC (Group 1: odds ratio [OR] = 0.912, 95% confidence interval [CI] = 0.690-1.204, P = .514; Group 2: OR = 1.038, 95% CI = 0.895-1.203, P = .623; Group 3: OR = 0.966, 95% CI = 0.851-1.096, P = .591; Group 4: OR = 1.103, 95% CI = 0.576-2.113, P = .768; Group 5: OR = 1.257, 95% CI = 0.511-1.037, P = .540; Group 6: OR = 0.728, 95% CI = 0.511-1.037, P = .079). Four complementary analyses further support this conclusion. Both the IVW and MR-Egger results indicate that the instrumental variables in each group did not exhibit significant pleiotropy. MR-Egger regression analysis showed no evidence of pleiotropic effects.

CONCLUSION

Our MR analysis suggests that PD does not significantly impact the risk of developing HCC. These results provide a new perspective on the relationship between these 2 conditions.

CLINICAL RELEVANCE

This MR study suggests no significant genetic causal relationship between PD and HCC, providing a new perspective. It indicates that clinicians may not need to over-intervene in periodontal disease to prevent liver cancer, thereby avoiding unnecessary psychological burden on patients.

IL-35 May Prevent the Exacerbation of Aspiration Pneumonia Involving Porphyromonas gingivalis by Suppressing IL-17 Production

Periodontitis is associated with aspiration pneumonia. However, the relationship between periodontitis and aspiration pneumonia remains unclear. This study investigated the virulence factor of Porphyromonas gingivalis, which exacerbates aspiration pneumonia, and the role of IL-35, an inhibitory heterodimeric cytokine of Epstein-Barr virus-induced gene 3 (EBI3) and p35, in aspiration pneumonia using Ebi3 knockout (KO) mice. Aspiration pneumonia was induced by the intratracheal injection of Streptococcus pneumoniae and P. gingivalis culture supernatant (mixed infection). Leupeptin was used to inhibit gingipain, a virulence factor of P. gingivalis. Four days after infection, lung tissues were collected for analyses. The percentage of interstitium in the group with mixed infection and leupeptin treatment was significantly reduced compared with the nonleupeptin administration group. Additionally, the percentage of interstitium in the field of Ebi3 KO mice was significantly increased compared with wild-type (WT) mice in mixed infection. IL-35 production in WT mice with mixed infection was significantly increased compared with the control group. IL-17 production in Ebi3 KO mice was significantly increased compared with WT mice with mixed infection. These findings suggest that gingipain exacerbates aspiration pneumonia and that IL-35 may contribute to suppressing the exacerbation of aspiration pneumonia.

Combining gut microbiota modulation and immunotherapy: A promising approach for treating microsatellite stable colorectal cancer

Colorectal cancer (CRC) is one of the most prevalent and lethal cancers worldwide, ranking third in incidence and second in mortality. While immunotherapy has shown promise in patients with deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H), its effectiveness in proficient mismatch repair (pMMR) or microsatellite stable (MSS) CRC remains limited. Recent advances highlight the gut microbiota as a potential modulator of anti-tumor immunity. The gut microbiome can significantly influence the efficacy of immune checkpoint inhibitors (ICIs), especially in pMMR/MSS CRC, by modulating immune responses and systemic inflammation. This review explores the role of the gut microbiota in pMMR/MSS CRC, the mechanisms by which it may enhance immunotherapy, and current strategies for microbiota modulation. We discuss the potential benefits of combining microbiota-targeting interventions with immunotherapy to improve treatment outcomes for pMMR/MSS CRC patients.

Attenuated NIX in impaired mitophagy contributes to exacerbating cellular senescence in experimental periodontitis under hyperglycemic conditions

Premature accumulation of senescent cells results in tissue destruction, and it is one of the potential primary mechanisms underlying the accelerated progression of diabetes and periodontitis. However, whether this characterized phenomenon could account for periodontal pathogenesis under hyperglycemic conditions remains unclear. In this study, we assessed the senescent phenotypic changes in experimental periodontitis under hyperglycemic conditions. Next, we investigated the mitochondrial function and the potential mitophagy pathways in cellular senescence in vitro and in vivo. Our findings showed that significant senescence occurred in the gingival tissues of diabetic periodontitis mice with increased expression of senescence-related protein p21Cip1 and the senescence-associated secretory phenotype response as well as the decreased expression of NIP3-like protein X (NIX), a mitochondrial receptor. Likewise, we showed that mitochondrial dysfunction (e.g., reduction of mitochondrial membrane potential and accumulation of reactive oxygen species) was attributed to cellular senescence in: human periodontal ligament cells (hPDLCs) through hyperglycemia-induced and Porphyromonas gingivalis lipopolysaccharide (P.g-LPS)-induced oxidative stresses. Notably, the resulting reduced NIX expression was reversed by the use of the mitochondrial reactive oxygen species (ROS) scavenger N-acetyl-l-cysteine (NAC), thus correcting the mitochondrial dysfunction. We further verified the expression of inflammatory mediators and senescence-related factors in mice gingival tissues and identified the possible regulatory pathways. Taken together, our work demonstrates the critical role of cellular senescence and mitochondrial dysfunction in periodontal pathogenesis under hyperglycemic conditions. Hence, restoration of mitochondrial function may be a potential novel therapeutic approach to tackling periodontitis in diabetic patients.

Porphyromonas gingivalis-derived lipopolysaccharide promotes mesangial cell fibrosis via transforming growth factor-beta1/Smad signaling pathway in high glucose

Background/purpose

Periodontitis has been documented to increase the risk of diabetic nephropathy. However, the specific mechanisms through which periodontitis affects renal function remain unclear. This study aimed to investigate the mechanism by which an inflammatory reaction stimulated by periodontal pathogens affects mesangial cell fibrosis under hyperglycemic conditions in vitro.

Materials and methods

Murine mesangial cells were stimulated with 1,000 ng/mL of Porphyromonas gingivalis-derived lipopolysaccharide (PgLPS) in a control or high glucose (HG) medium. Activation of the extracellular signal-regulated kinase (ERK1/2) and expression of alpha-smooth muscle actin (α-SMA) and collagen type 1a2 (Col1a2) were analyzed for fibrosis and transformation via the transforming growth factor (TGF)-β1/Smad signaling pathway.

Results

PgLPS stimulation significantly upregulated TGF-β1 expression and Smad3 phosphorylation in the HG group compared to the control group. Additionally, activation of ERK1/2 and expression of Col1a2 and α-SMA were significantly elevated in the HG group compared to the control following PgLPS stimulation. The TGF-β1 inhibitor significantly suppressed Smad3 phosphorylation and mRNA expression of Col1a2 in the HG group.

Conclusion

Under HG conditions, PgLPS may aggravate fibrosis in mesangial cells via the TGF-β1/Smad signaling pathway, leading to nephrosclerotic modifications. The presented study may support the association between periodontitis and chronic kidney disease, mediated by hyperglycemia.

Exploring the Nonlinear Relationship Between Dietary Flavonoid Intake and Periodontitis

INTRODUCTION AND AIMS

Flavonoids are non-nutrient bioactive substances widely found in plants, possessing antioxidant and anti-inflammatory properties. Periodontitis is a long-term inflammatory disease that impacts the tissues supporting the teeth, poses a substantial burden on public health and individuals alike. This study aims to explore the association between dietary flavonoid intake and periodontitis.

METHODS

This study included 3005 participants from the 2009 to 2010 National Health and Nutrition Examination Survey. We compared the weighted prevalence of periodontitis across different participant groups. Binary logistic regression analysis was conducted to evaluate the relationship between dietary flavonoid intake and periodontitis. The restricted cubic spline plot was used to explore nonlinear relationships.

RESULTS

The prevalence of periodontitis among participants with total flavonoid intake in quartiles Q1 to Q4 was 54.95%, 44.11%, 40.62%, and 48.28%, respectively. When compared to the Q1 group of total flavonoid intake, the OR values for Q2 to Q4 groups were 0.58 (95% CI: 0.39-0.86, P = .01), 0.50 (95% CI: 0.35-0.73, P = .001), and 0.68 (95% CI: 0.50-0.91, P = .01), respectively. A significant nonlinear association was observed between ln-transformed total flavonoid intake and the likelihood of developing periodontitis (nonlinearity P < .001). The inflection point was identified at an ln-transformed total flavonoid intake of 4.05, corresponding to a total flavonoid intake of 57.54 mg. Beyond this inflection point, as the total flavonoid intake value continues to rise, there was a diminishing protective effect against periodontitis.

CONCLUSIONS

Higher dietary flavonoid intake is associated with a reduced risk of periodontitis, with the greatest protective effect observed at moderate intake levels.

CLINICAL RELEVANCE

Understanding the association between flavonoid intake and periodontitis can guide dietary recommendations and interventions aimed at preventing periodontitis. This study supports the potential role of a flavonoid-rich diet in promoting periodontal health, suggesting that dietary modifications could be a viable strategy in periodontal disease prevention and management.

Testing the Causal Association Between Metabolic Syndrome and Periodontitis: A Two-sample Mendelian Randomisation Study

INTRODUCTION AND AIMS

Observational studies suggest an association between metabolic syndrome (MetS) and periodontitis. However, observational studies are susceptible to reverse causation and confounding factors, so the causality of this association is uncertain. Causal association between compounds of MetS and periodontitis has been well studied. Using Mendelian randomisation (MR), we aimed to comprehensively evaluate the bidirectional relationship between MetS as a whole and periodontitis and provide clinical insight.

METHODS

We used genetic instruments from the most comprehensive genome-wide association studies of European descent for MetS (n = 291,107) as well as periodontitis from both the FinnGen consortium (n = 195,395) and GeneLifestyle Interactions in Dental Endpoints (GLIDE, n = 45,563) consortium to investigate the causal relationship between MetS and periodontitis and vice versa. We used the inverse-variance weighted (IVW) method to derive the primary causal estimates and evaluated the robustness of our results with a series of sensitivity analyses.

RESULTS

MR analysis based on FinnGen consortium indicated a negative causal association of MetS on periodontitis (OR = 0.882, 95% CI = 0.791-0.983, P = .023), while MR analysis based on GLIDE consortium did not support a causal relation of MetS on periodontitis (OR = 0.986, 95% CI = 0.920-1.057, P = .697). These results were consistent after adjusting for potential confounding factors by multivariable MR analyses. Results from meta analysis did not support a causal association of MetS on periodontitis. Sensitivity analysis showed that there was no existence of pleiotropy. In the reverse direction, periodontitis showed no association with MetS.

CONCLUSIONS

Within the scope of this MR study, MetS and periodontitis are not causally related.

CLINICAL RELEVANCE

Further studies are needed to clarify the underlying mechanism between metabolic syndrome and periodontitis.

Understanding the peroxisome proliferator-activated receptor gamma (PPAR-γ) role in periodontitis and diabetes mellitus: A molecular perspective

Periodontitis and Type 2 Diabetes Mellitus (T2DM) are chronic conditions with dysregulated immune responses. Periodontitis involves immune dysfunction and dysbiotic biofilms, leading to tissue destruction. T2DM is marked by insulin resistance and systemic inflammation, driving metabolic and tissue damage. Both conditions share activation of key pathways, including Nuclear Factor Kappa B (NF-κB), Activator Protein-1 (AP-1), and Signal Transducer and Activator of Transcription (STAT) proteins, reinforcing an inflammatory feedback loop. This review highlights the role of Peroxisome Proliferator-Activated Receptor Gamma (PPAR-γ), a transcription factor central to lipid and glucose metabolism, adipogenesis, and immune regulation. PPAR-γ activation has been shown to suppress inflammatory mediators such as Tumor Necrosis Factor Alpha (TNF-α) and Interleukin 6 (IL-6) through the inhibition of NF-κB, AP-1, and STAT pathways, thereby potentially disrupting the inflammatory-metabolic cycle that drives both diseases. PPAR-γ agonists, including thiazolidinediones (TZDs) and endogenous ligands such as 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2), show promise in reducing inflammation and improving insulin sensitivity, but they are limited by adverse effects. Therapies, including Selective Peroxisome Proliferator-Activated Receptor Modulators (SPPARMs), have been developed to offer a more targeted approach, allowing for selective modulation of PPAR-γ activity to retain its anti-inflammatory benefits while minimizing their side effects. By integrating insights into PPAR-γ's molecular mechanisms, this review underscores its therapeutic potential in mitigating inflammation and enhancing metabolic control.

Therapeutic Potential of Extracellular Vesicles in Oral Inflammation

The therapeutic potential of extracellular vesicles (EVs) in reducing oral inflammation is thoroughly examined in this review, with an emphasis on gingivitis, periodontitis, and oral mucositis. It explains the complex relationship between microbial dysbiosis and host immune responses in the aetiology of oral inflammation. Pathophysiological mechanisms of periodontitis are examined, emphasising the roles played by periodontal pathogens and inflammatory mediators in the disease's chronic course and systemic effects. Preclinical research is providing new evidence that EVs originating from various cellular sources control immune cell dynamics towards a pro-healing phenotype, promote tissue regeneration, and have immunomodulatory qualities. EV-based therapies appear to be a promising new therapeutic technique with potential benefits over traditional methods for the treatment of oral inflammatory illnesses by specifically altering inflammatory signalling pathways. This review highlights the potential of EVs to improve patient outcomes in oral health and emphasises the need for additional clinical research to clarify the therapeutic efficacy and underlying mechanisms of EVs in periodontal therapy.

Investigating the link between oral health conditions and systemic diseases: A cross-sectional analysis

This study investigates the association between oral health issues, specifically periodontitis and dental caries, and systemic health conditions such as diabetes and hypertension. The goal is to determine the strength of these associations using statistical analysis. We conducted a cross-sectional study utilizing the National Health and Nutrition Examination Survey (NHANES) data from 2017-2020, focusing on 13,772 adults with complete data on oral and systemic health variables. Oral health indicators were periodontitis and dental caries, while systemic health variables included diabetes and hypertension. The statistical analysis involved Cramer's V to assess the strength of associations between these health conditions. The study found statistically significant associations between oral and systemic health conditions. There was a moderate association between periodontitis and diabetes (Cramer's V = 0.14) and a moderate association between dental caries and hypertension (Cramer's V = 0.12). The results underscore the interconnected nature of oral and systemic health, suggesting that poor oral health can be an indicator of broader health issues. These associations could guide integrated health care strategies, emphasizing the need for dental health evaluations in patients with diabetes and hypertension.

The association between periodontitis and arterial stiffening among the hypertensive middle-aged and elderly U.S. Population

Arterial stiffening is an independent predictor of cardiovascular diseases, closely associated with hypertension and aging. Periodontitis, a chronic inflammatory disease caused by microbial imbalances, has been linked to systemic inflammation and endothelial dysfunction. This study aims to investigate the association between periodontitis and arterial stiffening in hypertensive individuals. Data utilized in this study were sourced from the 2009-2014 National Health and Nutrition Examination Survey (NHANES). A total of 3165 hypertensive patients aged ≥ 50 years were enrolled. The relationship between the severity of periodontitis and arterial stiffening (PP ≥ 60) was analyzed using multivariate logistic regression model. Moreover, the associations between pocket depth (PD) and clinical attachment loss (CAL) with arterial stiffening were investigated using multivariate logistic regression model and restricted cubic splines. Among the patients, 1223 (39%) exhibited no or mild periodontal disease, while 1447 (46%) and 495 (15%) were diagnosed with moderate and severe periodontal disease, respectively. Moderate and severe periodontitis were associated with higher odds of arterial stiffening compared to no/mild periodontitis in the fully adjusted model (moderate: OR 1.30 [95% CI 1.09-1.55], P = 0.004; severe: OR 1.35 [95% CI 1.05-1.73], P = 0.019; P for trend < 0.001). Higher quartiles of PD and CAL scores were significantly associated with greater odds of arterial stiffening (PD Q4 vs. Q1: OR 1.41 [95% CI 1.12-1.79], P = 0.004; CAL Q4 vs. Q1: 1.31 [95% CI 1.03-1.67], P = 0.030), with evidence of linear dose-response relationships (P non-linear association=0.114 for PD; P non-linear association=0.308 for CAL). Subgroup analyses showed that the association between periodontitis severity and arterial stiffening remained significant in participants without diabetes or chronic kidney disease. In hypertensive patients aged 50 years and over, periodontitis is associated with elevated PP, thus reinforcing the association between periodontitis and arterial stiffening. Screening and treating periodontitis may offer additional clinical benefits.

New considerations in selecting donors for dental pulp stem cells: a pilot study

BACKGROUND/PURPOSE

Tissue engineering based on stem cell therapy necessitates a substantial quantity of high-quality stem cells. However, current sources face limitations, including narrow donor pools, compromised biological properties due to cryopreservation, and cellular senescence resulting from in vitro passaging and expansion. This study examines the impact of mild periodontitis on the biological performance of dental pulp stem cells (DPSCs) to explore the potential of broadening the donor pool for these cells.

MATERIALS AND METHODS

The experiment included two variables: age and the presence of periodontitis. DPSCs were isolated from six healthy subjects and six patients with mild periodontitis. Healthy subjects were categorized into Groups A (28-32 years) and B (52-54 years), and patients with mild periodontitis were categorized into Groups C (31-33 years) and D (50-53 years). The analyses included cell morphology, proliferation rate, multilineage differentiation capacity, apoptosis, and surface marker expression.

RESULT

No significant differences in cell morphology, pluripotency, or senescence were observed between healthy controls and periodontitis patients across age groups. Additionally, data on proliferation, pluripotency, and senescence were not significantly different. In healthy subjects, increased age was correlated with more elongated, flattened, and broader cells, alongside greater heterogeneity and intercellular granules. The proliferation and differentiation capacities decreased, whereas the degree of apoptosis increased. Similar trends were noted in patients with periodontitis.

CONCLUSION

The biological properties of DPSCs remain unchanged in teeth with mild periodontitis, providing valuable insights for addressing the shortage of DPSCs in tissue engineering. Teeth with mild periodontitis have the potential to be pulp stem cell donors.

Elongation factor Tu promotes the onset of periodontitis through mediating bacteria adhesion

Periodontitis, a leading cause of adult tooth loss and linked to various systemic diseases, is promoted by subgingival plaque biofilms, with Streptococci as early colonizers responsible for surface adhesion. Current studies of Streptococci adhesion have focused on bacteria surface adhesins with acquired protein membranes on the tooth surface, yet no critical proteins with implications for the overall early adhesion of subgingival plaque have been reported. Here, we identified that the "Barrel-like adhesion domain" of streptococcal EF-Tu facilitates cell-surface attachment, promotes biofilm formation, and contributes to the development of periodontitis. In the adherent state, EF-Tu is transported from the cytoplasm to the cell surface through membrane vesicles. Furthermore, we first found that simeprevir, an FDA-approved drug, binds to the "Barrel-like adhesion domain" of EF-Tu and effectively inhibits the protein's surface adhesion and secretory pathways. Simeprevir showed the ability to inhibit dental plaque formation and provided prevention and treatments for periodontitis.

[Prevotella nigrescens exacerbates periodontal inflammation and impairs cognitive function in mice]

OBJECTIVES

To investigate the effects of periodontitis induced by Prevotella nigrescens (Pn) combined with ligation on cognitive functions in mice.

METHODS

Twenty-four C57BL/6J mice were randomly divided into control group, ligation group, and ligation + Pn treatment (P+Pn) group. Experimental periodontitis was induced by silk ligation of the first molars followed by topical application of Pn for 6 weeks. After modeling, alveolar bone resorption was assessed using micro-CT and histological analysis. Learning and memory abilities of the mice were evaluated using open field test (OFT), novel object recognition test (NORT), and Morris water maze test (MWM). Seven weeks after the start of modeling, the mice were sacrificed for examining histopathological changes in the hippocampus using HE and Nissl staining.

RESULTS

After 6 weeks of molar ligation, micro-CT revealed horizontal alveolar bone resorption and furcation exposure in the mice, and histological analysis showed apical migration of the junctional epithelium, epithelial ridge hyperplasia, and lymphocyte infiltration, and these changes were obviously worsened in P+Pn group. Alveolar bone height decreased significantly in both ligation groups compared to the control group. Cognitive tests showed that the mice in both of the ligation groups traveled shorter distances in OFT, showed reduced novel object preference in NORT, and exhibited longer escape latencies in MWM, and the mice in P+Pn group had significantly poorer performances in the tests. Histologically, obvious neuronal cytoplasmic degeneration, necrosis, nuclear pyknosis, vacuolation, and reduced Nissl bodies and viable neurons were observed in the hippocampal regions of the mice in the two ligation groups.

CONCLUSIONS

Pn infection aggravates alveolar bone destruction, accelerates necrosis and causes morphological abnormalities of neuronal cells in the hippocampus to reduce cognitive functions of mice with periodontitis.

Atrial Translocation of Porphyromonas gingivalis Exacerbates Atrial Fibrosis and Atrial Fibrillation

BACKGROUND

Recent studies have indicated an association between periodontitis and atrial fibrillation (AF), although the underlying mechanisms remain unclear. Porphyromonas gingivalis is a causative agent of periodontal disease and is highly pathogenic. This study focused on P gingivalis and aimed to investigate the relationship among periodontitis, atrial translocation of P gingivalis, and atrial fibrosis and AF.

METHODS

An experiment was conducted using P gingivalis-infected C57BL/6J mice, in which P gingivalis was inoculated into the pulp of the molars. Immunohistochemistry was used to visualize the localization of P gingivalis, and loop-mediated isothermal amplification was employed to detect P gingivalis DNA in the left atrium. AF inducibility was examined by intracardiac stimulation. Moreover, left atrial appendage specimens were obtained from 68 patients with AF. A periodontal examination was conducted before the surgery, and the periodontal epithelial surface area and periodontal inflamed surface area, which are quantitative indices used to determine the clinical severity of periodontitis, were measured. The bacterial number of P gingivalis in human atrial tissue was analyzed via quantitative polymerase chain reaction. Atrial fibrosis was assessed using Azan-Mallory staining.

RESULTS

The translocation path of P gingivalis from the dental granuloma to the left atrium via the circulatory system was demonstrated by immunohistochemistry and loop-mediated isothermal amplification in P gingivalis-infected mice, which showed a higher degree of atrial fibrosis (21.9% versus 16.3%; P=0.0003) and a higher AF inducibility (30.0% versus 5.0%; P=0.04) than the control mice. Upregulation of GAL3 (galectin 3) and transforming growth factor-beta 1 in the left atrium was observed in P gingivalis-infected mice. Moreover, immunohistochemistry revealed that P gingivalis was also present in human atrial tissue. The number of P gingivalis in the human atrial tissue was positively correlated with periodontal epithelial surface area (ρ=0.35; P=0.004), periodontal inflamed surface area (ρ=0.52, P<0.0001), and the degree of atrial fibrosis (ρ=0.38; P=0.002).

CONCLUSIONS

P gingivalis translocation to the left atrium correlates with the clinical severity of periodontitis, which may exacerbate atrial fibrosis and AF. Atrial translocation of P gingivalis is a potential pathway explaining the causal relationship between periodontitis and AF.

Critical roles of extracellular vesicles in periodontal disease and regeneration

Extracellular vesicles (EVs) are evolutionarily conserved communication mediators that play key roles in the development of periodontal disease as well as in regeneration processes. This concise review first outlines the pathogenic mechanisms through which EVs derived from bacteria lead to the progression of periodontitis, with a focus on the enrichment of virulence factors, the amplification of immune responses, and the induction of bone destruction as key aspects influenced by bacterial EVs. This review aims to elucidate the positive effects of EVs derived from mesenchymal stem cells (MSC-EVs) on periodontal tissue regeneration. In particular, the anti-inflammatory properties of MSC-EVs and their impact on the intricate interplay between MSCs and various immune cells, including macrophages, dendritic cells, and T cells, are described. Moreover, recent advancements regarding the repair-promoting functions of MSC-EVs are detailed, highlighting the mechanisms underlying their ability to promote osteogenesis, cementogenesis, angiogenesis, and the homing of stem cells, thus contributing significantly to periodontal tissue regeneration. Furthermore, this review provides insights into the therapeutic efficacy of MSC-EVs in treating periodontitis within a clinical context. By summarizing the current knowledge, this review aims to provide a comprehensive understanding of how MSC-EVs can be harnessed for the treatment of periodontal diseases. Finally, a discussion is presented on the challenges that lie ahead and the potential practical implications for translating EV-based therapies into clinical practices for the treatment of periodontitis.

Bioinformatics Approach to Investigating the Immuno-Inflammatory Mechanisms of Periodontitis in the Progression of Atherosclerosis

Unstable atherosclerotic plaques are a major cause of acute cardiovascular events and ischemic stroke. Clinical studies have suggested a link between periodontitis and atherosclerotic plaque progression, but the underlying mechanisms remain unclear. To investigate this, transcriptomic datasets related to periodontitis and atherosclerosis were downloaded from Gene Expression Omnibus. A weighted gene co-expression network analysis was used to identify gene modules associated with periodontitis, and the Limma R package identified differentially expressed genes (DEGs) between unstable and stable plaques. Overlapping genes were defined as periodontitis-related DEGs, followed by functional enrichment analysis and protein-protein interaction network construction. Machine learning methods were used to identify biomarkers for unstable plaques related to periodontitis, which were validated using external datasets. Immune infiltration and single-cell analyses were performed to explore the relationship between biomarkers and immune cells. A total of 161 periodontitis-related DEGs were identified, with the pathway analysis showing associations with immune regulation and collagen matrix degradation. HCK, NCKAP1L, and WAS were identified as biomarkers for unstable plaques, demonstrating a high diagnostic value (AUC: 0.9884, 95% CI: 0.9641-1). Immune infiltration analysis revealed an increase in macrophages within unstable plaques. Single-cell analysis showed HCK expression in macrophages and dendritic cells, while NCKAP1L and WAS were expressed in macrophages, dendritic cells, NK cells, and T cells. Consensus clustering identified three expression patterns within unstable plaques. Our findings were validated in atherosclerotic mouse models with periodontitis. This study provides insights into how periodontitis contributes to plaque instability, supporting diagnosis and intervention in patients with periodontitis.

Distribution and Characteristics of Oral Pathogens According to Blood Glucose Levels in South Korean Health Examinees

The distribution of oral pathogens is influenced by genetic background, diet, socioeconomic status, and racial factors. This study aimed to assess the distribution and characteristics of oral pathogens based on blood glucose levels in a South Korean population. This cross-sectional, retrospective study included subjects from 17 health promotion centers in 13 South Korean cities between November 2021 and December 2022. Real-time multiplex PCR was used to detect 10 periodontitis-related pathogens, 6 dental caries-related pathogens, and 1 dental caries-protective bacterium. The most prevalent periodontitis-related pathogens were Parvimonas micra (97.6%), Porphyromonas endodontalis (96.8%), and Treponema socranskii (95.0%). Among dental caries-related pathogens, Streptococcus sanguinis and Veillonella parvula were found in all subjects. The prevalence of periodontitis-related pathogens was higher in males, while pathogens related to periodontitis and dental caries were more prevalent in older individuals. In the diabetes group, Aggregatibacter actinomycetemcomitans, red and orange complexes, and Streptococcus mutans were more prevalent. The relative amount of S. sanguinis was lower, while V. parvula was higher in individuals with diabetes mellitus. The prevalence and composition of oral pathogens vary by sex, age, and blood glucose levels. Diabetic individuals showed a pathogenic community structure linked to increased risks of periodontitis and dental caries.

Real-Time Polymerase Chain Reaction (PCR) Quantification of Periodontal Pathogenic Bacteria (Porphyromonas gulae, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) in Dogs

The present study investigated the molecular presence of 4 species of pathogenic periodontal bacteria (Porphyromonas gulae, Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola) using quantitative real-time polymerase chain reaction (PCR) in 230 household dogs with or without gingivitis, dental plaque and/or calculus. Overall, T. forsythia was most frequently present (77.8%), followed by P. gulae (50.9%), T. denticola (38.7%), and P. gingivalis (34.8%). A higher percentage of these bacteria was associated with factors such as age, grade of gingivitis, and an increase in dental plaque and/or calculus that indicated poor oral cleanliness. Even without a direct relation to gingivitis and plaque and/or calculus, these 4 species were consistently found not only in older dogs but also in younger ones. The results suggest that these bacteria are commonly present in household dogs, which puts them at risk of developing periodontal disease. Considering that 3 species of bacteria, excluding P. gulae, have zoonotic potential, it emphasizes the need for caution to prevent transmission between dogs and humans. Regarding overall bacterial DNA copy numbers, there was a wide range, with P. gulae having the most, followed by T. forsythia, P. gingivalis, and finally, T. denticola. The copy numbers did not always correlate with prevalence. The DNA copy numbers of T. forsythia were significantly lower in cases of higher-grade gingivitis and when there was poor oral cleanliness. These findings highlight the complexity of the interplay between bacterial type, prevalence, DNA copy numbers, and the oral health of household dogs.