From focal sepsis to periodontal medicine: a century of exploring the role of the oral microbiome in systemic disease

Emerging concepts in mucosal immunity and oral microecological control of respiratory virus infection-related inflammatory diseases

Oral microecological imbalance is closely linked to oral mucosal inflammation and is implicated in the development of both local and systemic diseases, including those caused by viral infections. This review examines the critical role of the interleukin (IL)-17/helper T cell 17 (Th17) axis in regulating immune responses within the oral mucosa, focusing on both its protective and pathogenic roles during inflammation. We specifically highlight how the IL-17/Th17 pathway contributes to dysregulated inflammation in the context of respiratory viral infections. Furthermore, this review explores the potential interactions between respiratory viruses and the oral microbiota, emphasizing how alterations in the oral microbiome and increased production of proinflammatory factors may serve as early, non-invasive biomarkers for predicting the severity of respiratory viral infections. These findings provide insights into novel diagnostic approaches and therapeutic strategies aimed at mitigating respiratory disease severity through monitoring and modulating the oral microbiome.

[Research and Progress on the Association of Porphyromonas gingivalis with Lung Cancer]

Porphyromonas gingivalis is a key pathogenic microorganism that triggers periodontitis. It is closely associated with oral diseases such as chronic periodontitis and recently found to have a significant correlation with the occurrence, progression, and prognosis of cancer. As the leading malignant tumor in terms of both incidence and mortality worldwide, lung cancer has always been a focus and hotspot of research. The causes of lung cancer are complex and involve multiple factors, including smoking, occupational factors, air pollution, ionizing radiation, diet and nutrition, genetic factors, etc. Researchers have also begun to pay attention to the relationship between oral microbiota and overall health, especially the link with lung cancer. The article summarizes the latest advancements in research on Porphyromonas gingivalis in lung cancer, primarily encompassing etiology and pathogenic mechanisms, and explores its potential as a therapeutic target for lung cancer, aiming to provide new insights and directions for lung cancer prevention and treatment strategies.
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Association between oral health conditions and the risk of major noncommunicable diseases: A protocol for systematic review and meta-analysis

Objective

Although epidemiological studies suggest that oral health conditions may be associated with an increased risk of noncommunicable diseases, the findings have yet to be comprehensively synthesized, particularly for a major noncommunicable diseases-related health and economic burden. Therefore, we will perform a systematic review and meta-analysis of all available observational studies investigating the association between oral health conditions and subsequent risk of major noncommunicable diseases.

Methods

With limited English publications, we will search electronic databases, including MEDLINE, Embase, PubMed, Cochrane Library, Scopus, and CINAHL. Based on the temporal properties and natural course of disease progression, we will seek cohort or case-control studies that investigate the association between oral disease conditions and the risk of noncommunicable diseases. Regarding the World Health Organization agenda, oral health conditions will include dental caries, periodontal disease, oral cancer, edentulism, other oral conditions (i.e., oro-dental trauma, cleft lip and palate, and noma), and endodontic lesions. Based on the global disease burden, primary outcomes of interest will include the four major systemic noncommunicable diseases: cardiovascular diseases, cancers, chronic respiratory diseases, and type 2 diabetes mellitus. Random-effects meta-analysis will be used to estimate pooled effects estimate and 95% confidence intervals. Statistical heterogeneity will be investigated using the I 2 index and τ 2 statistics. Preplanned subgroup and sensitivity analyses and random-effects meta-regression analyses will be performed to address possible heterogeneity and establish the robustness of the meta-analytic estimates. The prediction intervals, expected (E)-value, and evidence certainty will be appraised to synthesize the findings and draw evidence-based conclusions.

Conclusion

This systematic review will summarize all available evidence regarding the association between oral health conditions and the risk of major noncommunicable diseases. The findings will encourage collaboration between oral health and primary care professionals for early detection and management of noncommunicable diseases and promote oral health well-being.

Systematic review registration

PROSPERO: CRD42021274184.

Differences in maternal subgingival microbiome between preterm and term births: The MOHEPI study

AIM

Periodontitis is a potential risk factor for preterm birth (PTB) in women; however, the causal relationship or the exact mechanism remain unknown. This study aimed to compare the oral microbiome features of mothers with full-term birth (FTB) with those who had preterm delivery.

METHODS

This study prospectively enrolled 60 women (30 mothers with PTB and 30 mothers with FTB), and subgingival plaque samples were collected and analysed by metagenomic 16S rDNA sequencing. Clinical measurements, including periodontal probing depth, clinical attachment level, modified gingival index (mGI) and plaque index, were performed to determine the periodontal state of the participants. Medical and obstetric data were collected as well.

RESULTS

Among the periodontal measurements, mGI score, reflecting the level of gingival inflammation, exhibited a statistically significant association with PTB (adjusted odds ratio 2.705, 95% confidence interval 1.074-6.811, p = .035). When subgroup analysis was conducted based on mean mGI scores (mGI ≥ 2, high inflammation [HI] versus mGI < 2, low inflammation [LI]), microbiome analysis revealed clear distinctions in microbial compositions between PTB and FTB mothers in both the HI and LI groups. Especially in the HI group, alpha diversity exhibited a decreasing trend in PTB mothers compared to FTB mothers. Beta diversity also revealed significant differences between the two groups. In Linear Discriminant Analysis Effect Size analysis, certain anaerobic taxa, including the genera Spirochaetes, Treponema and Porphyromonas, were relatively abundant in the FTB/HI group, whereas the PTB/HI group showed a high abundance of the order Actinomycetales. Network analysis showed that the FTB/HI had relatively stronger connectivity in microbial composition than the PTB/HI group. Dysbiosis ratio of plaque microbiome, in terms of periodontitis, was significantly lower in PTB/HI group compared to FTB/HI group.

CONCLUSION

The compositions of maternal subgingival microbiomes differed between PTB and FTB mothers in both the high and low levels of gingival inflammation groups. In the presence of high level of gingival inflammation, dysbiosis in plaque microbiome, in terms of periodontitis, was decreased in PTB mothers compared to FTB mothers.

Oral microbiome diversity shapes the association between sleep duration and depression

Background

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

Methods

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

Results

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

Conclusion

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

Current clinical framework on nitric oxide role in periodontal disease and blood pressure

OBJECTIVES

In this review, we explored potential associations between NO and its derivatives, nitrite and nitrate, with periodontal and cardiovascular diseases, with special emphasis on the former. By providing a state-of-the-art and integrative understanding of this topic, we aimed to shed light on the potential role of these three nitrogen oxides in the periodontitis-hypertension nexus, identify knowledge gaps, and point out critical aspects of the experimental methodologies.

MATERIALS AND METHODS

A comprehensive literature review was conducted on human salivary and plasma concentrations of nitrate and nitrite, and their impact on periodontal and cardiovascular health.

RESULTS

A nitrate-rich diet increases nitrate and nitrite levels in saliva and plasma, promoting oral health by favorably altering the oral microbiome. Chlorhexidine (CHX) mouthrinses disrupt the nitrate-nitrite-NO pathway, reducing NO bioavailability, and potentially affecting blood pressure. This is because CHX eliminates nitrate-reducing bacteria, which are essential for NO production. Although endogenous NO production may be insufficient, the nitrate-nitrite-NO pathway plays a critical role in maintaining appropriate endothelial function, which is balanced by the microbiome and dietary nitrate intake. Dietary nitrate supplementation may lead to beneficial changes in the oral microbiome, thereby increasing the NO bioavailability. However, NO bioavailability can be compromised by reactive oxygen species (ROS) and the uncoupling of endothelial nitric oxide synthase (eNOS), leading to further ROS generation and creating a detrimental cycle. Studies on NO and periodontal disease have shown increased nitrite concentrations in patients with periodontal disease, although these studies have some methodological limitations. In terms of blood pressure, literature suggests that CHX mouthrinses may reduce the capacity of nitrate-reducing bacteria, potentially leading to an increase in blood pressure.

CONCLUSIONS

Several studies have suggested an association between NO levels and the development of cardiovascular and periodontal diseases. However, the exact mechanisms linking these diseases remains to be fully elucidated.

CLINICAL RELEVANCE

Nitric oxide (NO) is a signaling molecule that plays a crucial role in several physiological processes such as vascular homeostasis, inflammation, immune cell activity, and pathologies such as hypertension and periodontitis.

The impact of dysbiosis in oropharyngeal and gut microbiota on systemic inflammatory response and short-term prognosis in acute ischemic stroke with preceding infection

Background

Stroke is a devastating disease and ranks as the second leading cause of death and disability globally. Several studies have shown that preceding infection (PI) of upper respiratory tract are strongly associated with acute ischemic stroke (AIS). However, the clinical implications and underlying pathological mechanisms remain unclear.

Methods

In this study, 16S rRNA gene sequencing was employed to compare the structural characteristics of oropharyngeal and gut microbiota in AIS patients with or without PI and normal controls (NCs; 30 cases each), and systemic inflammatory markers were detected to explore the relationship between upper respiratory tract infections (URTIs) and subsequent stroke severity and functional outcome and the potential mechanism.

Results

We found that patients with AIS-PI exhibited elevated serum WBC, NE, CRP, and Hcy levels, as well as a higher 90-day mRS score. Oropharyngeal and gut microbiota analysis showed that AIS and AIS-PI patients exhibited increased microbial richness in sequence. Principal coordinate analysis of the microbiota demonstrated significant differences in microbiota composition among the three groups. In AIS-PI patients, Megamonas, Megasphaera, Ruminococcaceae UCG 004, Rothia, and Streptococcus were significantly enriched in the gut. Opportunistic pathogens, including Thermus, uncultured Veillonella sp., and Oribacterium sinu, were found to be significantly enriched in the oropharynx. The dysregulated microbiota were positively correlated with systemic inflammatory markers, stroke severity, and poor prognosis. In contrast, short-chain fatty acid-producing bacteria Eisenbergiella, bacterium NLAE, Fusicatenibacter, Ruminococcaceae, and Faecalibacterium were enriched in NCs. Their abundances were negatively correlated with systemic inflammatory markers, stroke severity and poor prognosis.

Conclusion

Our findings suggest that PIs of the upper respiratory tract may contribute to poor short-term functional outcome in AIS patients by causing disturbance of the oropharyngeal and gut microbiota and promoting elevated systemic inflammation levels.

[Integrating risks for oral diseases into Structured Information Collection: A practice development project]

Integrating risks for oral diseases into Structured Information Collection: A practice development project Abstract: Background: Deficient oral hygiene and oral diseases are highly prevalent among nursing staff. Up to now, there is no assessment for nursing professionals integrated in the daily nursing routine, which depicts the complex risks for oral diseases. The Structured Information Collection (SIS) is a concept to guide the nursing process and enables individual action planning. Aim: The aim was to integrate oral diseases as a nursing-relevant risk into the SIS and to develop an assessment instrument for oral hygiene deficits/diseases integrated into the SIS topic areas. Methods: Based on a literature search, 21 systematic reviews describing SIS topic areas and oral health risks were analysed by a panel of experts. The caregiver-relevant oral health risks identified in this way were compared with existing oral health assessment instruments and with screening criteria recommended in the German national expert standard for the promotion of oral health in care. Since none of the oral health assessments covers all nursing-relevant oral health risks and the recommended screening criteria of the expert standard, the area of "oral diseases" was integrated into the SIS as an additional category, and an oral health assessment adapted to the SIS was developed. Results: This article presents the SIS expanded to include nursing-relevant oral disease risk and the newly developed Oral Risk Assessment Prevention (Mu-RAP) for use by nurses. Conclusions: The SIS expanded to include oral disease and the Mu-RAP for identifying oral hygiene deficits/diseases cover all nursing-relevant oral health risks. Further studies on the applicability, reliability, and validity of the instrument, as well as on care-effective and patient-relevant effects of its use are needed.

Chitosan-coated liposomal systems for delivery of antibacterial peptide LL17-32 to Porphyromonas gingivalis

Periodontal disease is triggered by surface bacterial biofilms where bacteria are less susceptible to antibiotic treatment. The development of liposome-based delivery mechanisms for the therapeutic use of antimicrobial peptides is an attractive alternative in this regard. The cationic antimicrobial peptide LL-37 (human cathelicidin) is well-known to exert antibacterial activity against P orphyromonas gingivalis, a keystone oral pathogen. However, the antibacterial activity of the 16-amino acid fragment (LL17-32) of LL-37, is unknown. In addition, there are still gaps in studies using liposomal formulations as delivery vehicles of antibacterial peptides against this pathogen. This study was designed to examine the influence of the different types of liposomal formulations to associate and deliver LL17-32 to act against P. gingivalis. Chitosans of varying Mw and degree of acetylation (DA) were adsorbed at the surface of soya lecithin (SL) liposomes. Their bulk (average hydrodynamic size, ζ-potential and membrane fluidity) and ultrastructural (d-spacing, half-bilayer thickness and the water layer thickness) biophysical properties were investigated by a panel of techniques (DLS, SAXS, M3-PALS, fluorescence spectroscopy and TEM imaging). Their association efficiency, in vitro release, stability, and efficacy in killing the periodontal pathogen P. gingivalis were also investigated. All liposomal systems possessed spherical morphologies and good shelf-life stabilities. Under physiological conditions, chitosan formulations with a high DA demonstrated enhanced stability in comparison to low DA-chitosan formulations. Chitosans and LL17-32 both decreased SL-liposomal membrane fluidity. LL17-32 exhibited a high degree of association with SL-liposomes without in vitro release. In biological studies, free LL17-32 or chitosans alone, demonstrated microbicidal activity against P. gingivalis, however this was attenuated when LL17-32 was loaded onto the SL-liposome delivery system, presumably due to the restrained release of the peptide. A property that could be harnessed in future studies (e.g., oral mucoadhesive slow-release formulations).

Concomitant pyogenic spondylodiscitis and empyema following tongue cancer resection and wisdom tooth extraction: A case report and literature review

RATIONALE

Pyogenic spondylodiscitis is an infectious spinal disease that causes significant motor dysfunctions. Its diagnosis can be challenging owing to its rapid onset and nonspecific symptoms.

PATIENT CONCERNS

A 79-year-old Japanese man with a history of type 2 diabetes mellitus and polymyalgia rheumatica presented to our department with tongue pain. Following partial glossectomy and wisdom tooth extraction under general anesthesia, on 10 postoperative day (POD) the patient developed right-sided abdominal pain and difficulty in walking. On 12 POD, the patient was admitted to a municipal hospital due to respiratory distress and paraplegia.

DIAGNOSES

The patient was diagnosed with pyogenic spondylodiscitis and empyema. Blood tests revealed elevated C-reactive protein levels (36.5), white blood cell count (19,570), and neutrophil count (17,867).

INTERVENTIONS

The patient received meropenem hydrate 3 g/2 days as empiric antibiotic treatment for acute infection. Upon admission to the emergency department on 16 POD, the lung abscess was drained, hemilaminectomy was performed.

OUTCOMES

Blood cultures, sputum tests, and cultures from the thoracic and spinal abscesses drained during surgery revealed methicillin-sensitive Staphylococcus aureus. The infection was successfully managed, and the respiratory disturbance and inflammatory response improved. However, the lower half of the patient body remained paralyzed. Subsequently, the patient was transferred to a rehabilitation facility on 45 POD. The patient continued to undergo functional restoration training, gradually regained function, and eventually achieved the ability to walk with grasping gait.

LESSONS

This is the first case report of S aureus causing pyogenic spondylodiscitis and empyema due to blood stream infection from a post-oral surgical wound. Pyogenic spondylodiscitis arising from a secondary hematogenous infection is difficult to diagnose and can lead to severe functional impairment. Prompt and appropriate diagnosis and treatment based on detailed patient interviews, additional blood tests, and computed tomography are essential.

Brazilin cream from Caesalpinia sappan inhibit periodontal disease: in vivo study

Background

Gingivitis is an inflammation of the gums that is the initial cause of the development of periodontal disease by the activity of Nuclear Factor-kappa B (NF-κB), Interleukin-1β (IL-1β), Interleukin-6 (IL-6), p38, and Tumor Necrosis Factor-α (TNF-α). Unaddressed chronic inflammation can lead to persistent disturbances in other parts of the body. Brazilin is a naturally occurring plant chemical that may have antibacterial and anti-inflammatory effects. Treatment based on the natural plant compound, brazilin, is developed in the form of a topical cream for easy application.

Objective

The aim is to develop the natural compound brazilin in the form of a topical cream as an anti-inflammatory agent to reduce NF-κB expression through Imunohistochemistry (IHC) methods, and the expression of pro-inflammatory genes IL-1β, IL-6, p38, and TNF-α.

Methods

Male Sprague-Dawley rats were induced with gingivitis using P. gingivalis bacteria. The observed groups included rats treated with a single application of brazilin cream and rats treated with two applications of brazilin cream. The treatment was administered for 15 days. On days 3, 6, 9, 12, and 15, anatomical wound observations and wound histology using hematoxylin-eosin and Masson's Trichrome staining were performed. NF-κB protein expression was analyzed using the IHC method. Gingival inflammation gene expression of NF-κB, IL-1β, IL-6, p38, and TNF-α was measured using q-RTPCR.

Results

Single and double applications of brazilin cream increased angiogenesis and decreased NF-κB protein expression, in addition to the IL-1β, IL-6, p38, and TNF-α gene expressions.

Conclusion

In a rat gingivitis model, Brazilin cream may function as an anti-inflammatory agent in the gingival tissue.

The Oral-Lung Microbiome Axis in Connective Tissue Disease-Related Interstitial Lung Disease

Connective tissue disease-related interstitial lung disease (CTD-ILD) is a frequent and serious complication of CTD, leading to high morbidity and mortality. Unfortunately, its pathogenesis remains poorly understood; however, one intriguing contributing factor may be the microbiome of the mouth and lungs. The oral microbiome, which is a major source of the lung microbiome through recurrent microaspiration, is altered in ILD patients. Moreover, in recent years, several lines of evidence suggest that changes in the oral and lung microbiota modulate the pulmonary immune response and thus may play a role in the pathogenesis of ILDs, including CTD-ILD. Here, we review the existing data demonstrating oral and lung microbiota dysbiosis and possible contributions to the development of CTD-ILD in rheumatoid arthritis, Sjögren's syndrome, systemic sclerosis, and systemic lupus erythematosus. We identify several areas of opportunity for future investigations into the role of the oral and lung microbiota in CTD-ILD.

Impact of dietary inflammatory index on gingival health

BACKGROUND

Periodontal disease is a biofilm-dependent chronic inflammatory condition triggered by a host response. Several factors impact systemic inflammation and could lead to changes in disease pathogenesis. Recently, studies have assessed the influence of nutritional patterns on the development of periodontitis. In the present cross-sectional study, we evaluated the dietary inflammatory profile on periodontal conditions, focusing on clinical, subgingival microbial, and cytokine assessment of individuals with periodontal health or gingivitis.

METHODS

One hundred patients with periodontal health or gingivitis were included. Plaque index (PI), Bleeding on probing (BoP), the probing depth (PD), and the clinical attachment level (CAL) for each patient were assessed. Nutritional data and the Dietary Inflammatory Index (DII) were recorded by two 24-h food recalls on non-consecutive days. Biofilm and gingival crevicular fluid (GCF) to assess the microbiome profile and inflammatory biomarkers were collected. Multiple regressions focused on the DII, age, and sex as predictors of periodontal conditions were done.

RESULTS

Age and moderate DII scores increased the risk of gingivitis by 1.64 and 3.94 times, respectively. Males with an elevated DII score had 27.15 times higher odds of being diagnosed with gingivitis and BoP (β = 6.54; p = 0.03). Elderly patients with a moderate or high DII score were less prone to gingivitis and increased BoP (p < 0.04) compared with younger subjects. Considering the DII, there were no differences in microbial alpha and beta diversity; however, distinct species abundance and a higher concentration of monocyte-chemoattractant protein-1 and interleukin 33 were seen in patients with a higher DII.

CONCLUSION

A pro-inflammatory diet significantly contributes to periodontal inflammation, modulating inflammatory biomarkers and affecting the subgingival microbial community in healthy individuals.

Update on Focal Infection Management: A Czech Interdisciplinary Consensus

BACKGROUND

The focal infection theory has been used to explain several chronic systemic diseases in the past. Systemic diseases were thought to be caused by focal infections, such as caries and periodontal diseases, and dentists were held responsible for these diseases due to the spread of oral infections. As knowledge of the interrelationship between oral microorganisms and the host immune response has evolved over the last few decades, the focal infection theory has been modified in various ways. The relationship between oral and systemic health appears to be more complex than that suggested by the classical theory of focal infections. Indeed, the contribution of the oral microbiota to some systemic diseases is gaining acceptance, as there are strong associations between periodontal disease and atherosclerotic vascular disease, diabetes, and hospital-associated pneumonia, amongst others. As many jurisdictions have various protocols for managing this oral-systemic axis of disease, we sought to provide a consensus on this notion with the help of a multidisciplinary team from the Czech Republic.

METHODS

A multidisciplinary team comprising physicians/surgeons in the specialities of dentistry, ear-nose and throat (ENT), cardiology, orthopaedics, oncology, and diabetology were quetioned with regard to their conceptual understanding of the focal infection theory particularly in relation to the oral-systemic axis. The team also established a protocol to determine the strength of these associations and to plan the therapeutic steps needed to treat focal odontogenic infections whenever possible.

RESULTS

Scoring algorithms were devised for odontogenic inflammatory diseases and systemic risks, and standardised procedures were developed for general use.

CONCLUSIONS

The designed algorithm of the oral-systemic axis will be helpful for all health care workers in guiding their patient management protocol.

Commensal Oral Microbiota, Disease Severity, and Mortality in Fibrotic Lung Disease

Rationale: Oral microbiota associate with diseases of the mouth and serve as a source of lung microbiota. However, the role of oral microbiota in lung disease is unknown. Objectives: To determine associations between oral microbiota and disease severity and death in idiopathic pulmonary fibrosis (IPF). Methods: We analyzed 16S rRNA gene and shotgun metagenomic sequencing data of buccal swabs from 511 patients with IPF in the multicenter CleanUP-IPF (Study of Clinical Efficacy of Antimicrobial Therapy Strategy Using Pragmatic Design in IPF) trial. Buccal swabs were collected from usual care and antimicrobial cohorts. Microbiome data were correlated with measures of disease severity using principal component analysis and linear regression models. Associations between the buccal microbiome and mortality were determined using Cox additive models, Kaplan-Meier analysis, and Cox proportional hazards models. Measurements and Main Results: Greater buccal microbial diversity associated with lower FVC at baseline (mean difference, -3.60; 95% confidence interval [CI], -5.92 to -1.29% predicted FVC per 1-unit increment). The buccal proportion of Streptococcus correlated positively with FVC (mean difference, 0.80; 95% CI, 0.16 to 1.43% predicted per 10% increase) (n = 490). Greater microbial diversity was associated with an increased risk of death (hazard ratio, 1.73; 95% CI, 1.03-2.90), whereas a greater proportion of Streptococcus was associated with a reduced risk of death (HR, 0.85; 95% CI, 0.73 to 0.99). The Streptococcus genus was mainly composed of Streptococcus mitis species. Conclusions: Increasing buccal microbial diversity predicts disease severity and death in IPF. The oral commensal S. mitis spp associates with preserved lung function and improved survival.

The Lung Microbiome

Although the lungs were once considered a sterile environment, advances in sequencing technology have revealed dynamic, low-biomass communities in the respiratory tract, even in health. Key features of these communities-composition, diversity, and burden-are consistently altered in lung disease, associate with host physiology and immunity, and can predict clinical outcomes. Although initial studies of the lung microbiome were descriptive, recent studies have leveraged advances in technology to identify metabolically active microbes and potential associations with their immunomodulatory by-products and lung disease. In this brief review, we discuss novel insights in airway disease and parenchymal lung disease, exploring host-microbiome interactions in disease pathogenesis. We also discuss complex interactions between gut and oropharyngeal microbiota and lung immunobiology. Our advancing knowledge of the lung microbiome will provide disease targets in acute and chronic lung disease and may facilitate the development of new therapeutic strategies.

Placental TLR recognition of salivary and subgingival microbiota is associated with pregnancy complications

BACKGROUND

Pre-term birth, the leading cause of neonatal mortality, has been associated with maternal periodontal disease and the presence of oral pathogens in the placenta. However, the mechanisms that underpin this link are not known. This investigation aimed to identify the origins of placental microbiota and to interrogate the association between parturition complications and immune recognition of placental microbial motifs. Video Abstract METHODS: Saliva, plaque, serum, and placenta were collected during 130 full-term (FT), pre-term (PT), or pre-term complicated by pre-eclampsia (PTPE) deliveries and subjected to whole-genome shotgun sequencing. Real-time quantitative PCR was used to measure toll-like receptors (TLR) 1-10 expression in placental samples. Source tracking was employed to trace the origins of the placental microbiota.

RESULTS

We discovered 10,007 functionally annotated genes representing 420 taxa in the placenta that could not be attributed to contamination. Placental microbial composition was the biggest discriminator of pregnancy complications, outweighing hypertension, BMI, smoking, and maternal age. A machine-learning algorithm trained on this microbial dataset predicted PTPE and PT with error rates of 4.05% and 8.6% (taxonomy) and 6.21% and 7.38% (function). Logistic regression revealed 32% higher odds of parturition complication (95% CI 2.8%, 81%) for every IQR increase in the Shannon diversity index after adjusting for maternal smoking status, maternal age, and gravida. We also discovered distinct expression patterns of TLRs that detect RNA- and DNA-containing antigens in the three groups, with significant upregulation of TLR9, and concomitant downregulation of TLR7 in PTPE and PT groups, and dense correlation networks between microbial genes and these TLRs. 70-82% of placental microbiota were traced to serum and thence to the salivary and subgingival microbiomes. The oral and serum microbiomes of PTPE and PT groups displayed significant enrichment of genes encoding iron transport, exosome, adhesion, quorum sensing, lipopolysaccharide, biofilm, and steroid degradation.

CONCLUSIONS

Within the limits of cross-sectional analysis, we find evidence to suggest that oral bacteria might translocate to the placenta via serum and trigger immune signaling pathways capable of inducing placental vascular pathology. This might explain, in part, the higher incidence of obstetric syndromes in women with periodontal disease.

Plant-based compositions for the treatment of local and topical bacterial infections: a patent review

Aim: To examine recent patents related to plants with antimicrobial effects. Methods: Our investigation was carried out using the Espacenet database, searching patents related to International Patent Classification (IPC) codes A61P31/04, and A61K36/00 between 2008 and 2023. Results: The study began with 360 patents, of which 15 were found to be duplicates; 144 were not related to the research topic and six were not available. Then, 48 patents were related to other administration routes. The final selection was 47 patents related to local administration compositions. The potential for these herbal compositions to be marketed as over-the-counter medicines was evident. Conclusion: Developing new plant-origin anti-infective agents could provide promising solutions for combating resistant infections and offer accessible treatment options.

Factors associated with oral health service utilization among young people in southern China

OBJECTIVES

To identify the patterns and influencing factors of oral health service utilization among college students, and further to provide scientific evidence for policy making on oral health education and behavioral interventions for the college population.

METHODS

The study population was college students in Southern China. Totally 678 students participated in the survey. A self-designed questionnaire based on Anderson's model (predisposing factors, enabling factors, need factors) was used to survey college students. Descriptive statistics, χ2 test, and logistic regression were used to analyze influence factors of oral health service utilization among college students.

RESULTS

The utilization rate of oral health service in the past 12 months was 30.2%. The primary type of oral health service was treatment (59.6%), and only 12.8% were for prevention. There were 39% of the participants having oral health diseases, of which dental caries (25.7%) and oral bleeding (22.2%) were the main problems. The results from logistic regression analysis revealed that students with better beliefs (OR = 1.84, 95% CI:=1.02-3.43), frequent consumption of sugary drinks (OR = 2.90, 95% CI:=1.90-4.47), teeth brushing frequency > = 2 times per day (OR = 2.09, 95% CI = 1.24-3.61), frequent floss utilization (OR = 2.63, 95% CI = 1.21-5.76), dental caries (OR = 2.07, 95% CI = 1.35-3.17) used oral health services higher, while those lived in rural areas (OR:0.52, 95% CI = 0.34-0.80), and had only a fair concern (OR = 0.48, 95% CI = 0.31-0.74) or no concern (OR = 0.26, 95% CI = 0.08-0.67) on oral health utilized oral health services lower.

CONCLUSIONS

Chinese college students demonstrate some knowledge and attitudes towards oral health. However, they tend to neglect oral hygiene and have limited understanding of their own oral issues. Furthermore, the utilization of oral services, such as treatment, remains remarkably low, despite the availability of long-term and favorable health insurance policies. The utilization of oral health services among college students is influenced by various factors, including residing in rural areas, consuming sugary beverages on a daily basis, brushing teeth at least twice a day, and practicing flossing.

From the Oral Cavity to the Spine: Prevalence of Oral Cavity Infections in Patients with Pyogenic Spinal Infection

Background incidence of pyogenic spinal infections has increased in recent years. In addition to treating the spinal infection, optimal care also includes identifying the source of the pyogenic spinal infection and the presence of other infections. The aim of this study is to elucidate the prevalence of oral cavity infection (OCI) within this patient cohort. Methods As part of a prospective study conducted from 2016 to 2021, the number of patients with dental infections was investigated by means of an orthopantomogram (OPG) and subsequent dental examination. Results The presence of an oral infection was investigated in 55 (47%) of 118 patients by an OPG, 29 (53%) of whom had a corresponding abnormality of the oral cavity. In addition to the spinal infection, patients with an oral cavity infection revealed an increased incidence of endocarditis, sepsis and brain abscess. A spinal epidural abscess, a multilevel affection of the infection, and an elevated CRP value were also found in patients with a co-existing oral cavity infection. Back pain assessed at admission and 3 months after surgery was also more pronounced in patients with an oral cavity infection. Neurological deficits were often present in patients with spinal and oral cavity infection. Conclusions The presence of an oral cavity infection has proven to be one of the important factors in the detection of the source of the pyogenic spinal infection. In addition, a pronounced spinal affection and frequent co-infections were seen in patients with an oral cavity infection.

Periodontal Disease and Alzheimer's: Insights from a Systematic Literature Network Analysis

This study investigated the relationship between periodontal disease (PD) and Alzheimer's Disease (AD) through a Systematic Literature Network Analysis (SLNA), combining bibliometric analysis with a Systematic Literature Review (SLR). Analyzing 328 documents from 2000 to 2023, we utilized the Bibliometrix R-package for multiple bibliometric analysis. The SLR primarily centered on the 47 most globally cited papers, highlighting influential research. Our study reveals a positive correlation between Periodontal Disease (PD) and Alzheimer's Disease (AD), grounded in both biological plausibility and a comprehensive review of the literature, yet the exact causal relationship remains a subject of ongoing scientific investigation. We conducted a detailed analysis of the two main pathways by which PD could contribute to brain inflammation: (a) the Inflammatory Cascade, and (b) Microbial Involvement. The results of our SLNA emphasize the importance of oral health in reducing Alzheimer's risk, suggesting that managing periodontal health could be an integral part of Alzheimer's prevention and treatment strategies. The insights from this SLNA pave the way for future research and clinical practices, underscoring the necessity of interdisciplinary methods in both the investigation and treatment of neurodegenerative diseases like Alzheimer's. Furthermore, our study presents a prospective research roadmap to support ongoing advancement in this field.

Alterations of the salivary microbiota in gastroesophageal reflux disease

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Gut microbiota interacts with inflammatory responses in acute pancreatitis

Acute pancreatitis (AP) is one of the most common acute abdominal conditions, and its incidence has been increasing for years. Approximately 15-20% of patients develop severe AP (SAP), which is complicated by critical inflammatory injury and intestinal dysfunction. AP-associated inflammation can lead to the gut barrier and function damage, causing dysbacteriosis and facilitating intestinal microbiota migration. Pancreatic exocrine deficiency and decreased levels of antimicrobial peptides in AP can also lead to abnormal growth of intestinal bacteria. Meanwhile, intestinal microbiota migration influences the pancreatic microenvironment and affects the severity of AP, which, in turn, exacerbates the systemic inflammatory response. Thus, the interaction between the gut microbiota (GM) and the inflammatory response may be a key pathogenic feature of SAP. Treating either of these factors or breaking their interaction may offer some benefits for SAP treatment. In this review, we discuss the mechanisms of interaction of the GM and inflammation in AP and factors that can deteriorate or even cure both, including some traditional Chinese medicine treatments, to provide new methods for studying AP pathogenesis and developing therapies.

Nisin a probiotic bacteriocin mitigates brain microbiome dysbiosis and Alzheimer's disease-like neuroinflammation triggered by periodontal disease

INTRODUCTION

Periodontitis-related oral microbial dysbiosis is thought to contribute to Alzheimer's disease (AD) neuroinflammation and brain amyloid production. Since probiotics can modulate periodontitis/oral dysbiosis, this study examined the effects of a probiotic/lantibiotic, nisin, in modulating brain pathology triggered by periodontitis.

METHODS

A polymicrobial mouse model of periodontal disease was used to evaluate the effects of this disease on brain microbiome dysbiosis, neuroinflammation, Alzheimer's-related changes, and nisin's therapeutic potential in this context.

RESULTS

16S sequencing and real-time PCR data revealed that Nisin treatment mitigated the changes in the brain microbiome composition, diversity, and community structure, and reduced the levels of periodontal pathogen DNA in the brain induced by periodontal disease. Nisin treatment significantly decreased the mRNA expression of pro-inflammatory cytokines (Interleukin-1β/IL-1 β, Interleukin 6/IL-6, and Tumor Necrosis Factor α/TNF-α) in the brain that were elevated by periodontal infection. In addition, the concentrations of amyloid-β 42 (Aβ42), total Tau, and Tau (pS199) (445.69 ± 120.03, 1420.85 ± 331.40, 137.20 ± 36.01) were significantly higher in the infection group compared to the control group (193.01 ± 31.82, 384.27 ± 363.93, 6.09 ± 10.85), respectively. Nisin treatment markedly reduced the Aβ42 (261.80 ± 52.50), total Tau (865.37 ± 304.93), and phosphorylated Tau (82.53 ± 15.77) deposition in the brain of the infection group.

DISCUSSION

Nisin abrogation of brain microbiome dysbiosis induces beneficial effects on AD-like pathogenic changes and neuroinflammation, and thereby may serve as a potential therapeutic for periodontal-dysbiosis-related AD.

Association between periodontitis and postoperative complications in hospital medical surgical procedures: a systematic review

Background

Periodontitis is potentially harmful in the perioperative period due to biofilm generating a environment for bacteria to spread and colonize other anatomical areas, which can generate a potential risk of infection, delayed healing, increased morbidity, and even induce avulsion in intubated patients, and subsequent aspiration or ingestion of teeth with increased mobility.

Objective

Associate the presence of periodontitis and postoperative complications in patients who underwent an in-hospital medical surgical procedure.

Methods

A systematic review based on studies extracted from PubMed and Scopus was carried out on June 10, 2020, based on the Population, Intervention, Comparison and Result search strategy. As inclusion criteria, the studies had to include all the disaggregated terms of the research question, have a publication date of less than 15 years, and the target population had to have undergone elective hospital medical-surgical interventions. The exclusion criteria corresponded to not presenting an analytical or experimental observational study design, not having made a periodontal clinical diagnosis of the study subjects, and not expressing in the results the presence of postoperative medical-hospital complications. Articles were assessed for quality by supplementing the STROBE guideline and Newcastle Ottawa, for risk of bias by supplementing the STROBE guideline and the Cochrane Collaboration handbook tool.

Results

A total of 131 articles were obtained, which were subjected to a selection process, resulting in 5 final analytical observational studies. A meta-analysis was performed and determined that periodontitis was a risk factor to postoperative complications after surgical procedures with an OR = 4,76; 95%CI [1,11-20,41].

Conclusions

Optimize the guidelines for assessing quality and risk of bias can make their comparison with other studies complex, however it was determined in a statistically significant way that patients with periodontitis have a higher risk of generating postoperative complications after a medical hospital surgery.

Effect of Periodontal Disease on Alzheimer's Disease: A Systematic Review

The aim of this review was to evaluate the relationship between periodontal disease (PD) and the onset and progression of Alzheimer's disease (AD) and to determine whether patients with PD would be at greater risk of developing AD compared to periodontally healthy subjects. This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search for cross-sectional, cohort, or case-control studies was conducted on five databases (PubMed, ScienceDirect, EBSCO, Web of Science, and Scopus). No restrictions were applied to the language and year of publication. Exposure was PD, and the outcome of interest was the onset and/or progression of AD. The risk of bias of the included studies was assessed using the Newcastle-Ottawa Scale (NOS) designed for non-randomized studies. Six studies fulfilling the selection criteria were included in this systematic review. Four of the studies were of cohort design and two were of case-control design. All except one showed a significant association between PD and the risk of AD onset and progression. According to the NOS bias risk assessment, three studies were found to be of good quality, and three other cohort studies were of low quality. Data from this systematic review indicate that patients with PD present a significantly higher risk of AD compared to individuals with healthy periodontium. However, results should be interpreted with caution given the methodological limitations found. For future research, powerful and comparable epidemiological studies are needed to evaluate the relationship between PD and AD.

Oral microbiota in human health and disease: A perspective

The evolution of medical knowledge about oral microbiota has increased awareness of its important role for the entire human body health. A wide range of microbial species colonizing the oral cavity interact both with each other and with their host through complex pathways. Usually, these interactions lead to a harmonious coexistence (i.e. eubiosis). However, several factors - including diet, poor oral hygiene, tobacco smoking, and certain medications, among others - can disrupt this weak homeostatic balance (i.e. dysbiosis) with potential implications on both oral (i.e. development of caries and periodontal disease) and systemic health. This article is thus aimed at providing an overview on the importance of oral microbiota in mediating several physiological and pathological conditions affecting human health. In this context, strategies based on oral hygiene and diet as well as the role of probiotics supplementation are discussed.

Microbiota present in combined endodontic-periodontal diseases and its risks for endocarditis

INTRODUCTION

Infective endocarditis (IE) is an inflammatory disease usually caused by bacteria that enter the bloodstream and establish infections in the inner linings or valves of the heart, including blood vessels. Despite the availability of modern antimicrobial and surgical treatments, IE continues to cause substantial morbidity and mortality. Oral microbiota is considered one of the most significant risk factors for IE. The objective of this study was to evaluate the microbiota present in root canal (RC) and periodontal pocket (PP) clinical samples in cases with combined endo-periodontal lesions (EPL) to detect species related to IE using NGS.

METHODS

Microbial samples were collected from 15 RCs and their associated PPs, also from 05 RCs with vital pulp tissues (negative control, NC). Genomic studies associated with bioinformatics, combined with structuring of a database (genetic sequences of bacteria reported for infective endocarditis), allowed for the assessment of the microbial community at both sites. Functional prediction was conducted using PICRUSt2.

RESULTS

Parvimonas, Streptococcus, and Enterococcus were the major genera detected in the RCs and PPs. A total of 79, 96, and 11 species were identified in the RCs, PPs, and NCs, respectively. From them, a total of 34 species from RCs, 53 from PPs, and 2 from NCs were related to IE. Functional inference demonstrated that CR and PP microbiological profiles may not be the only risk factors for IE but may also be associated with systemic diseases, including myocarditis, human cytomegalovirus infection, bacterial invasion of epithelial cells, Huntington's disease, amyotrophic lateral sclerosis, and hypertrophic cardiomyopathy. Additionally, it was possible to predict antimicrobial resistance variants for broad-spectrum drugs, including ampicillin, tetracycline, and macrolides.

CONCLUSION

Microorganisms present in the combined EPL may not be the only risk factor for IE but also for systemic diseases. Antimicrobial resistance variants for broad-spectrum drugs were inferred based on PICRUSt-2. State-of-the-art sequencing combined with bioinformatics has proven to be a powerful tool for conducting studies on microbial communities and could considerably assist in the diagnosis of serious infections.

CLINICAL RELEVANCE

Few studies have investigated the microbiota in teeth compromised by combined endo-periodontal lesions (EPL), but none have correlated the microbiological findings to any systemic condition, particularly IE, using NGS techniques. In such cases, the presence of apical periodontitis and periodontal disease can increase IE risk in susceptible patients.

Metagenomic analysis of oral plaques and aortic valve tissues reveals oral bacteria associated with aortic stenosis

OBJECTIVES

Bacteria derived from the oral cavity enter the bloodstream and cause the onset of various systemic diseases, including heart valve disease. However, information on the oral bacteria involved in aortic stenosis is limited.

MATERIALS AND METHODS

We comprehensively analyzed the microbiota in aortic valve tissues collected from aortic stenosis patients using metagenomic sequencing and investigated the relationships between the valve microbiota, the oral microbiota, and oral cavity conditions.

RESULTS

Metagenomic analysis revealed the presence of 629 bacterial species in five oral plaques and 15 aortic valve clinical specimens. Patients were classified into two groups (A and B) according to their aortic valve microbiota composition using principal coordinate analysis. Examination of the oral conditions of the patients showed no difference in the decayed/missing/filled teeth index. Bacteria in group B tend to be associated with severe disease, and the number of bacteria on the dorsum of the tongue and the positive rate of bleeding during probing were significantly higher in this group than in group A. The pathophysiology of aortic stenosis may be related to the presence of oral bacteria such as Streptococcus oralis and Streptococcus sanguinis following bacteremia.

CONCLUSIONS

Systemic inflammation in severe periodontitis may be driven by the oral microbiota, supporting the indirect (inflammatory) association between oral bacteria and aortic stenosis.

CLINICAL RELEVANCE

Appropriate oral hygiene management may contribute to the prevention and treatment of aortic stenosis.

Periodontal Disease and Other Adverse Health Outcomes Share Risk Factors, including Dietary Factors and Vitamin D Status

For nearly a century, researchers have associated periodontal disease (PD) with risks of other adverse health outcomes such as cardiovascular disease, diabetes mellitus, and respiratory diseases, as well as adverse pregnancy outcomes. Those findings have led to the hypothesis that PD causes those adverse health outcomes either by increasing systemic inflammation or by the action of periodontopathic bacteria. However, experiments largely failed to support that hypothesis. Instead, the association is casual, not causal, and is due to shared underlying modifiable risk factors, including smoking, diet, obesity, low levels of physical activity, and low vitamin D status. Diabetes mellitus is also considered a risk factor for PD, whereas red and processed meat are the most important dietary risk factors for diabetes. Because PD generally develops before other adverse health outcomes, a diagnosis of PD can alert patients that they could reduce the risk of adverse health outcomes with lifestyle changes. In addition, type 2 diabetes mellitus can often be reversed rapidly by adopting an anti-inflammatory, nonhyperinsulinemic diet that emphasizes healthful, whole plant-based foods. This review describes the evidence that proinflammatory and prohyperinsulinemia diets and low vitamin D status are important risk factors for PD and other adverse health outcomes. We also make recommendations regarding dietary patterns, food groups, and serum 25-hydroxyvitamin D concentrations. Oral health professionals should routinely inform patients with PD that they could reduce their risk of severe PD as well as the risks of many other adverse health outcomes by making appropriate lifestyle changes.

General Factors and Dental-Related Risk Factors for Postoperative Pneumonia or Infectious Complications: A Retrospective Study

Numerous studies report that perioperative oral care decreases the frequency of postoperative pneumonia or infection. However, no studies have analyzed the specific impact of oral infection sources on the postoperative course, and the criteria for preoperative dental care differ among institutions. This study aimed to analyze the factors and dental conditions present in patients with postoperative pneumonia and infection. Our results suggest that general factors related to postoperative pneumonia, including thoracic surgery, sex (male > female), the presence or absence of perioperative oral management, smoking history, and operation time, were identified, but there were no dental-related risk factors associated with it. However, the only general factor related to postoperative infectious complications was operation time, and the only dental-related risk factor was periodontal pocket (4 mm or higher). These results suggest that oral management immediately before surgery is sufficient to prevent postoperative pneumonia, but that moderate periodontal disease must be eliminated to prevent postoperative infectious complication, which requires periodontal treatment not only immediately before surgery, but also on a daily basis.

Prevalence of Asthma, Allergic Rhinitis, and Atopic Dermatitis and Their Association With Oral Health in Saudi Arabia

Background  The word "atopy" is frequently used to describe immunoglobulin E (IgE)-mediated diseases. The prevalence of atopic dermatitis, allergic rhinitis, and asthma is increasing and disconcerting in Saudi Arabia. This study aims to investigate the association between allergic rhinitis, atopic dermatitis, asthma, and oral health among adults in the Makkah region of Saudi Arabia. Methods A cross-sectional study of 726 adults using an electronic questionnaire was adopted. The study was carried out from January to December 2022. The questionnaire included demographic data, patients' diseases in response to inclusion and exclusion criteria, oral health status and symptoms, and dental health-related behaviors. Results Most participants were aged from 18 to <40 years (79.1%). More than half of the participants were females (53.6%); 39.7% of participants had poor oral health. Poor health was significantly higher among obese subjects as well as those with lower levels of physical activity, higher perceived levels of stress, those who received a sealant, and those who brushed their teeth for ≤ one time per day. The results showed that the individual symptoms of oral health did not associate significantly with being diagnosed with allergic rhinitis or asthma in the past 12 months. However, atopic dermatitis was independently associated with a chipped or broken tooth (OR = 1.52) and pain in the tongue or inside the cheeks (OR = 3.57). Conclusion Poor oral health was significantly associated with atopic dermatitis in Saudi adults. Some systemic diseases are considered chronic diseases, and they are multifactorial; thus, we cannot claim that periodontal pathogens are the definite cause of systemic infections. More studies are necessary to find a definitive association.

Differential oral microbiome in nonhuman primates from periodontitis-susceptible and periodontitis-resistant matrilines

Rhesus monkeys (n = 36) exhibiting a healthy periodontium at baseline were used to induce progressing periodontitis through ligature placement around premolar/molar teeth. Bacterial samples were collected at baseline, 0.5, 1, and 3 months of disease and at 5 months for disease resolution. The animals were distributed into two groups (18/group): 3-7 years (young) and 12-23 years (adult) and stratified based upon matriline susceptibility to periodontitis (PDS, susceptible; PDR, resistant). A total of 444 operational taxonomic units (OTUs) with 100 microbes representing a core microbiome present in ≥75% of the samples were identified. Only 48% of the major phylotypes overlapped in the PDS and PDR samples. Different OTU abundance patterns were seen in young animals from the PDS and PDR matrilines, with qualitative similarities during disease and the relative abundance of phylotypes becoming less diverse. In adults, 23 OTUs were increased during disease in PDS samples and 24 in PDR samples; however, only five were common between these groups. Greater diversity of OTU relative abundance at baseline was observed with adult compared to young oral samples from both the PDS and PDR groups. With disease initiation (2 weeks), less diversity of relative abundance and some distinctive increases in specific OTUs were noted. By 1 month, there was considerable qualitative homogeneity in the major OTUs in both groups; however, by 3 months, there was an exacerbation of both qualitative and quantitative differences in the dominant OTUs between the PDS and PDR samples. These results support that some differences in disease expression related to matriline (familial) periodontitis risk may be explained by microbiome features.

Does the Loss of Teeth Have an Impact on Geriatric Patients’ Cognitive Status?

Significant changes in the microstructure of the brain cause dementia and other mental declines associated with aging and disease. Although research has established a connection between oral health and dementia, the underlying pathologic mechanisms are still unknown. Aim: Our aim was to evaluate dentures’ impact on the cognitive state of geriatric patients. Material and methods: A total of 108 individuals seeking treatment at the Faculty of Dental Medicine in Iasi, Romania, participated in the study, which ran from May 2022 to October 2022. Cognitive dysfunction was assessed using the Mini-Mental State Examination. The acquired data were analyzed with IBM SPSS 26.0, and the p-value was set at 0.05. Results: The average value of the MMSE score was 21.81 ± 3.872. Differences between groups of wearer/non-wearer subjects were statistically significant for most of the questions in the questionnaire. Linear regression analysis showed that individuals with a high MMSE score have prosthodontic treatment. A decrease in the MMSE score is associated with a decrease in masticatory efficiency (B = 1.513, p = 0.268). Conclusions: This study provides further evidence that tooth loss is associated with worse cognitive performance. It is thus conceivable that the necessary effects can be achieved by increasing the efforts dedicated to preventing tooth loss in the adult population.

The Human Respiratory Microbiome: Current Understandings and Future Directions

Microorganisms colonize the human body. The lungs and respiratory tract, previously believed to be sterile, harbor diverse microbial communities and the genomes of bacteria (bacteriome), viruses (virome), and fungi (mycobiome). Recent advances in amplicon and shotgun metagenomic sequencing technologies and data-analyzing methods have greatly aided the identification and characterization of microbial populations from airways. The respiratory microbiome has been shown to play roles in human health and disease and is an area of rapidly emerging interest in pulmonary medicine. In this review, we provide updated information in the field by focusing on four lung conditions, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, and idiopathic pulmonary fibrosis. We evaluate gut, oral, and upper airway microbiomes and how they contribute to lower airway flora. The discussion is followed by a systematic review of the lower airway microbiome in health and disease. We conclude with promising research avenues and implications for evolving therapeutics.

Oral microbial dysbiosis in patients with periodontitis and chronic obstructive pulmonary disease

Background

Oral microbiota is closely related to the homeostasis of the oral cavity and lungs. To provide potential information for the prediction, screening, and treatment strategies of individuals, this study compared and investigated the bacterial signatures in periodontitis and chronic obstructive pulmonary disease (COPD).

Materials and methods

We collected subgingival plaque and gingival crevicular fluid samples from 112 individuals (31 healthy controls, 24 patients with periodontitis, 28 patients with COPD, and 29 patients with both periodontitis and COPD). The oral microbiota was analyzed using 16S rRNA gene sequencing and diversity and functional prediction analysis were performed.

Results

We observed higher bacterial richness in individuals with periodontitis in both types of oral samples. Using LEfSe and DESeq2 analyses, we found differentially abundant genera that may be potential biomarkers for each group. Mogibacterium is the predominant genus in COPD. Ten genera, including Desulfovibrio, Filifactor, Fretibacterium, Moraxella, Odoribacter, Pseudoramibacter Pyramidobacter, Scardovia, Shuttleworthia and Treponema were predominant in periodontitis. Bergeyella, Lautropia, Rothia, Propionibacterium and Cardiobacterium were the signature of the healthy controls. The significantly different pathways in the Kyoto Encyclopedia of Genes and Genomes (KEGG) between healthy controls and other groups were concentrated in genetic information processing, translation, replication and repair, and metabolism of cofactors and vitamins.

Conclusions

We found the significant differences in the bacterial community and functional characterization of oral microbiota in periodontitis, COPD and comorbid diseases. Compared to gingival crevicular fluid, subgingival plaque may be more appropriate for reflecting the difference of subgingival microbiota in periodontitis patients with COPD. These results may provide potentials for predicting, screening, and treatment strategies for individuals with periodontitis and COPD.

Provision of Dental Care to Indigenous South Australians and Impacts on Improved General Health: Study Protocol

BACKGROUND

Indigenous South Australians carry a disproportionate burden of dental diseases, with approximately 80 percent of Indigenous adults having both periodontal disease and dental caries. The chronic inflammatory nature of many dental conditions means there are widespread systemic impacts, particularly on type 2 diabetes, chronic kidney disease and cardiovascular disease. Evidence suggests there are barriers experienced by Indigenous South Australians in accessing timely and culturally safe dental care. This study aims to: (1) elicit the views of Indigenous South Australians regarding their perspectives of what comprises culturally safe dental care; (2) provide such dental care and; (3) assess any changes in both oral and general health using point-of-care testing following receipt of timely, comprehensive and culturally safe dental care.

METHODS/DESIGN

This mixed-methods study will involve qualitative interviews and an intervention without randomisation. The qualitative component will comprise seeking perspectives of Indigenous South Australians regarding what culturally safe dental care means for them. For the intervention component, participants will take part in oral epidemiological examinations at baseline and 12-month follow-up (after receipt of dental care), which will include collection of saliva, plaque and calculus, as well as completion of a self-report questionnaire. The primary outcome measures-changes in type 2 diabetes (HbA1c), cardiovascular disease (CRP) and chronic kidney disease (ACR)-will be obtained by blood/urine spot from a finger prick/urine collection at baseline and 12-month follow-up via point-of-care testing.

RESULTS

Participant recruitment will commence in July 2022. The first results are expected to be submitted for publication one year after recruitment begins.

DISCUSSION

The project will have a number of important outcomes, including increased understanding of what culturally safe dental care means for Indigenous South Australians, the delivery of such care, and empirical evidence of how culturally safe dental care leads to better prognosis for chronic diseases linked with poor oral health. This will be important for health services planning, especially in the Aboriginal Community Controlled Health Organisation sector, where the management of dental diseases in a culturally safe manner for better chronic disease outcomes is currently insufficiently understood, planned and budgeted for.

Microbiome, alveolar bone, and metabolites: Connecting the dots

The oral microbiome (OM) is a diverse and dynamic collection of species, separated from alveolar bone by the oral mucosa. Pathogenic shifts in the OM (dysbiosis) during periodontitis are associated with an inflammatory response in the oral mucosa that drives alveolar bone resorption. Alveolar bone is also affected by metabolic disorders such as osteoporosis. Accumulating evidence has linked another microbial community, the gut microbiome (GM), to systemic bone metabolism and osteoporosis. Underlying this connection is the biologic activity of metabolites, byproducts of host and bacterial activity. Limited evidence also suggests that metabolites in the oral cavity signal between the OM and immune system, influencing both alveolar bone homeostasis and pathologic bone destruction in periodontitis. While the oral cavity and gut are connected through the gastrointestinal tract, dissimilar roles for known metabolites between these two niches exemplify the difficulty in translating knowledge on gut-derived metabolites and bone metabolism to alveolar bone. Integrated metabolomic, transcriptomic, and metagenomic approaches hold promise for resolving these challenges and identifying novel metabolites which impact alveolar bone health. Further interrogation through mechanistic testing in pre-clinical models and carefully controlled clinical studies have potential to lead toward translation of these discoveries into meaningful therapies.

The Oral Microbiota in Valvular Heart Disease: Current Knowledge and Future Directions

Oral microbiota formation begins from birth, and everything from genetic components to the environment, alongside the host's behavior (such as diet, smoking, oral hygiene, and even physical activity), contributes to oral microbiota structure. Even though recent studies have focused on the gut microbiota's role in systemic diseases, the oral microbiome represents the second largest community of microorganisms, making it a new promising therapeutic target. Periodontitis and dental caries are considered the two main consequences of oral bacterial imbalance. Studies have shown that oral dysbiosis effects are not limited locally. Due to technological advancement, research identified oral bacterial species in heart valves. This evidence links oral dysbiosis with the development of valvular heart disease (VHD). This review focuses on describing the mechanism behind prolonged local inflammation and dysbiosis, that can induce bacteriemia by direct or immune-mediated mechanisms and finally VHD. Additionally, we highlight emerging therapies based on controlling oral dysbiosis, periodontal disease, and inflammation with immunological and systemic effects, that exert beneficial effects in VHD management.

An umbrella review of the evidence linking oral health and systemic noncommunicable diseases

Oral diseases are highly prevalent worldwide. Recent studies have been supporting a potential bidirectional association of oral diseases with systemic noncommunicable diseases (NCDs). Available evidence supports that people with NCDs have a greater prevalence of oral diseases particularly those with limited ability of oral self-care. Regarding the reverse relationship, the lines of evidence pointing out NCDs as putative risk factors for oral diseases have increased significantly but not with a consistent agreement. This umbrella review of meta-analyses appraises the strength and validity of the evidence for the association between oral health and systemic health (registered at PROSPERO, ID: CRD42022300740). An extensive search included systematic reviews that have provided meta-analytic estimates on the association of oral diseases with NCDs. The overall strength of evidence was found to be unfavorable and with methodological inconsistencies. Twenty-eight NCDs were strongly associated with oral diseases. Among those NCDs are five types of cancer, diabetes mellitus, cardiovascular diseases, depression, neurodegenerative conditions, rheumatic diseases, inflammatory bowel disease, gastric helicobacter pylori, obesity, and asthma. According to fail-safe number statistics, the evidence levels are unlikely to change in the future, indicating a fairly robust consistency.

Analysis of subgingival micro-organisms based on multi-omics and Treg/Th17 balance in type 2 diabetes with/without periodontitis

Type 2 diabetes mellitus (T2DM) and periodontitis are common and interrelated diseases, resulting in altered host response microbiota. The subgingival micro-organisms play a key role in periodontitis pathogenesis. To assess the shift of subgingival microbiome and metabolome in T2DM, we performed an analysis of the subgingival microbiome in patients with T2DM (n = 20) compared with non-diabetes (ND) subjects (n = 21). Furthermore, patients were subdivided into 10 T2DM with periodontitis (DP), 10 T2DM without periodontitis (DNP), 10 periodontitis (P), and 11 healthy control (H) groups. 16SrRNA gene sequencing combined with ultra high-performance liquid chromatography-mass spectrometry (UHPLC-MS) based metabolomics was performed in all participants. T lymphocyte immunity was analyzed by flow cytometry. Furthermore, the network relationship among subgingival micro-organisms, metabolites, blood glucose level, and T lymphocyte immunity were analyzed. The results showed that the difference of the subgingival microbiome from healthy to periodontitis status was less prominent in T2DM compared with ND, though the clinical signs of disease were similar. The bacteria Eubacterium nodatum group, Filifactor, Fretibacterium, Peptostreptococcus, and Desulfovibrio, amongst others, may be important in the pathopoiesia of periodontitis in the T2DM state. In addition, some dominant bacteria showed network relationships. The Treg/Th17 ratio was lower in the DP and DNP groups than in the P and H groups-though that of P was lower than for H. The percentage of CD4+/CD8+ PD1 and CD8+ PDL1 was higher in the DP and DNP groups than in the H group; the percentage of CD8+ PDL1 was higher in the DP than P groups. Subgingival micro-organisms in periodontitis had a significant metabolic shift in terms of their signature metabolites. Butyrate metabolism and phenylalanine metabolism may play a role in the pathogenesis of periodontitis with/without T2DM. Specifically, biphenyl degradation, tryptophan metabolism, and the two-component system may play important roles in periodontitis with T2DM. Lastly, the network relationship among subgingival micro-organisms, metabolites, blood glucose level, and T lymphocyte immunity were unbalanced. This study identified the changes in the subgingival microbiome associated with periodontitis in T2DM, as well as the associated network between bacterial flora, metabolism dysbiosis, and immune regulation.

Continuous Oral Administration of Sonicated P. gingivalis Delays Rat Skeletal Muscle Healing Post-Treadmill Training

BACKGROUND

A delay in muscle repair interferes with the effect of training or exercise; therefore, it is important to identify the factors that delay muscle repair. P. gingivalis, one of the most common periodontal disease pathogens, has the potential to inhibit muscle repair after training, as inferred from a previous study. To assess the expression of satellite cells in this in vivo study, we evaluated the relationship between P. gingivalis and muscle regeneration after training.

METHODS

A total of 20 male Wistar rats (eight weeks in age) were randomly divided into two groups: one orally administered sonicated P. gingivalis four times per week for six weeks (PG group) and one given no treatment (NT group). After four weeks of training using a treadmill, the gastrocnemius was evaluated using histology of the cross-sectional area (CSA) of myotubes and immunohistochemistry of the expression of skeletal muscle satellite cells. In addition, an endurance test was performed a day before euthanization.

RESULTS

The CSA and expression of Pax7+/MyoD- and Pax7+/MyoD+ cells were not significantly different between the groups. However, the expression of Pax7-/MyoD+ cells and running time until exhaustion were significantly lower in the PG group.

CONCLUSIONS

Infection with P. gingivalis likely interferes with muscle repair after training.

Effects of stabilized hypochlorous acid on oral biofilm bacteria

Background

Caries and periodontitis are amongst the most prevalent diseases worldwide, leading to pain and loss of oral function for those affected. Prevention relies heavily on mechanical removal of dental plaque biofilms but for populations where this is not achievable, alternative plaque control methods are required. With concerns over undesirable side-effects and potential bacterial resistance due to the use of chlorhexidine gluconate (CHX), new antimicrobial substances for oral use are greatly needed. Here we have investigated the antimicrobial effect of hypochlorous acid (HOCl), stabilized with acetic acid (HAc), on oral biofilms and compared it to that of CHX. Possible adverse effects of stabilized HOCl on hydroxyapatite surfaces were also examined.

Methods

Single- and mixed-species biofilms of six common oral bacteria (Streptococcus mutans, Streptococcus gordonii, Actinomyces odontolyticus, Veillonella parvula, Parvimonas micra and Porphyromonas gingivalis) within a flow-cell model were exposed to HOCl stabilized with 0.14% or 2% HAc, pH 4.6, as well as HOCl or HAc alone. Biofilm viability was assessed in situ using confocal laser scanning microscopy following LIVE/DEAD® BacLight™ staining. In-situ quartz crystal microbalance with dissipation (QCM-D) was used to study erosion of hydroxyapatite (HA) surfaces by stabilized HOCl.

Results

Low concentrations of HOCl (5 ppm), stabilized with 0.14% or 2% HAc, significantly reduced viability in multi-species biofilms representing supra- and sub-gingival oral communities, after 5 min, without causing erosion of HA surfaces. No equivalent antimicrobial effect was seen for CHX. Gram-positive and Gram-negative bacteria showed no significant differential suceptibility to stabilized HOCl.

Conclusions

At low concentrations and with exposure times which could be achieved through oral rinsing, HOCl stabilized with HAc had a robust antimicrobial activity on oral biofilms, without causing erosion of HA surfaces or affecting viability of oral keratinocytes. This substance thus appears to offer potential for prevention and/or treatment of oral biofilm-mediated diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12903-022-02453-2.

Dietary magnesium intake is protective in patients with periodontitis

Background

Periodontitis is a chronic inflammatory disease of the oral cavity characterized by inflammation of the periodontal tissue and resorption of the alveolar bone, which has a high incidence and is the main cause of tooth loss in adults. In addition to its role in promoting osteogenesis, magnesium also has a role in regulating the inflammatory response, both systemically and locally. There is growing evidence that magnesium is an important factor in maintaining the normal functioning of the body's immune system. Hypomagnesaemia can lead to a variety of chronic inflammatory diseases throughout the body, including periodontitis. Two-thirds of the US population suffers from magnesium deficiency. The connection between dietary magnesium and periodontitis is unknown. As a result, we set out to investigate the link between dietary magnesium intake and periodontitis.

Methods

In this study, we collected data from the National Health and Nutrition Examination Survey (NHANES) database from 2013 to 2014. Through 24-h dietary recalls, information about food consumption was collected. We examined the association between the dietary magnesium and periodontitis using multivariable logistic regression model. Based on odds ratios (OR) and 95% confidence intervals (CIs), a strong association was detected.

Results

Multivariable logistic regression analysis showed that the OR for periodontitis comparing the highest to the lowest quintile of dietary magnesium intake was 0.69 (95% CIs = 0.52~0.92). The restricted cubic spline (RCS) analysis showed that the non-linear association between dietary magnesium and periodontitis was statistically significant and that dietary magnesium supplementation reduced the prevalence of periodontitis.

Conclusion

Dietary magnesium intake is associated with the prevalence of periodontitis. Dietary magnesium deficiency increases the prevalence of periodontitis.

Can metagenomics unravel the impact of oral bacteriome in human diseases?

Oral microbial ecosystems are vital in maintaining the health of the oral cavity and the entire body. Oral microbiota is associated with the progression of oral diseases such as dental caries, periodontal diseases, head and neck cancer, and several systemic diseases such as cardiovascular disease, rheumatoid arthritis, adverse pregnancy outcomes, diabetes, lung infection, colorectal cancer, and pancreatic cancer. Buccal mucosa, tongue dorsum, hard palate, saliva, palatine tonsils, throat, keratinized gingiva, supra-gingival plaque, subgingival plaque, dentures, and lips are microbial habitats of the oral cavity. Porphyromonas gingivalis may have a role in the development of periodontal diseases, oral cancer, diabetes, and atherosclerotic disease. Fusobacterium nucleatum showed a higher abundance in periodontal diseases, oral and colon cancer, adverse pregnancy outcomes, diabetes, and rheumatoid arthritis. The higher abundance of Prevotella intermedia is typical in periodontal diseases, rheumatoid arthritis, and adverse pregnancy outcome. S. salivarius displayed higher abundance in both dental caries and OSCC. Oral bacteria may influence systemic diseases through inflammation by releasing pro inflammatory cytokines. Identification of oral bacteria using culture-dependent approaches and next-generation sequencing-based metagenomic approaches is believed to significantly identify the therapeutic targets and non-invasive diagnostic indicators in different human diseases. Oral bacteria in saliva could be exploited as a non-invasive diagnostic indicator for the early detection of oral and systemic disorders. Other therapeutic approaches such as the use of probiotics, green tea polyphenol, cold atmospheric plasma (CAP) therapy, antimicrobial photodynamic therapy, and antimicrobial peptides are used to inhibit the growth of biofilm formation by oral bacteria.

The oral microbiome, pancreatic cancer and human diversity in the age of precision medicine

Pancreatic cancer is a deadly disease with limited diagnostic and treatment options. Not all populations are affected equally, as disparities exist in pancreatic cancer prevalence, treatment and outcomes. Recently, next-generation sequencing has facilitated a more comprehensive analysis of the human oral microbiome creating opportunity for its application in precision medicine. Oral microbial shifts occur in patients with pancreatic cancer, which may be appreciated years prior to their diagnosis. In addition, pathogenic bacteria common in the oral cavity have been found within pancreatic tumors. Despite these findings, much remains unknown about how or why the oral microbiome differs in patients with pancreatic cancer. As individuals develop, their oral microbiome reflects both their genotype and environmental influences. Genetics, race/ethnicity, smoking, socioeconomics and age affect the composition of the oral microbiota, which may ultimately play a role in pancreatic carcinogenesis. Multiple mechanisms have been proposed to explain the oral dysbiosis found in patients with pancreatic cancer though they have yet to be confirmed. With a better understanding of the interplay between the oral microbiome and pancreatic cancer, improved diagnostic and therapeutic approaches may be implemented to reduce healthcare disparities. Video Abstract.

No-ozone cold plasma can kill oral pathogenic microbes in H2O2-dependent and independent manner

To apply the sterilisation effect of low-temperature plasma to the oral cavity, the issue of ozone from plasma must be addressed. In this study, a new technology for generating cold plasma with almost no ozone is developed and is named Nozone (no-ozone) Cold Plasma (NCP) technology. The antimicrobial efficacy of the NCP against four oral pathogens is tested, and its specific mechanism is elucidated. The treatment of NCP on oral pathogenic microbes on a solid medium generated a growth inhibition zone. When NCP is applied to oral pathogens in a liquid medium, the growth of microbes decreased by more than 10⁵ colony forming units, and the bactericidal effect of NCP remained after the installation of dental tips. The bactericidal effect of NCP in the liquid medium is due to the increase in hydrogen peroxide levels in the medium. However, the bactericidal effect of NCP in the solid medium depends on the charged elements of the NCP. Furthermore, the surface bactericidal efficiency of the dental-tip-installed NCP is proportional to the pore size of the tips and inversely proportional to the length of the tips. Overall, we expect this NCP device to be widely used in dentistry in the near future.

Metabolomics Research in Periodontal Disease by Mass Spectrometry

Periodontology is a newer field relative to other areas of dentistry. Remarkable progress has been made in recent years in periodontology in terms of both research and clinical applications, with researchers worldwide now focusing on periodontology. With recent advances in mass spectrometry technology, metabolomics research is now widely conducted in various research fields. Metabolomics, which is also termed metabolomic analysis, is a technology that enables the comprehensive analysis of small-molecule metabolites in living organisms. With the development of metabolite analysis, methods using gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, capillary electrophoresis–mass spectrometry, etc. have progressed, making it possible to analyze a wider range of metabolites and to detect metabolites at lower concentrations. Metabolomics is widely used for research in the food, plant, microbial, and medical fields. This paper provides an introduction to metabolomic analysis and a review of the increasing applications of metabolomic analysis in periodontal disease research using mass spectrometry technology.