Association between periodontal pathogens and systemic disease

Regulatory role of PDK1 via integrated gene analysis of mitochondria-immune response in periodontitis

AIMS

To investigate the association between mitochondrial events and immune response in periodontitis and related regulatory genes.

MAIN METHODS

Gene expression profiles in gingival tissues were retrieved from the Gene Expression Omnibus. Mitochondria-immune response-related differentially expressed genes (MIR-DEGs) between the healthy and periodontitis samples were determined. WGCNA, GO, and KEGG were used to investigate the function and the enriched pathways of MIR-DEGs. The correlation between MIR-DEGs expression and clinical probing pocket depth was analyzed. The MIR-DEGs were further identified and verified in animal samples. A periodontitis model was established in C57BL/6 mice with silk ligation. Micro-computed tomography was used to assess alveolar bone loss. Western blot, quantitative real-time polymerase chain reaction, and immunohistochemical analyses further validated the differential expression of the MIR-DEGs.

KEY FINDINGS

A total of ten MIR-DEGs (CYP24A1, PRDX4, GLDC, PDK1, BCL2A1, CBR3, ARMCX3, BNIP3, IFI27, and UNG) were identified, the expression of which could effectively distinguish patients with periodontitis from the healthy controls. Enhanced immune response was detected in the periodontitis group with that in the healthy controls, especially in B cells. PDK1 was a critical MIR-DEG correlated with B cell immune response and clinical periodontal probing pocket depth. Both animal and clinical periodontal samples presented higher gene and protein expression of PDK1 than the control samples. Additionally, PDK1 colocalized with B cells in both animal and clinical periodontal tissues.

SIGNIFICANCE

Mitochondria participate in the regulation of the immune response in periodontitis. PDK1 may be the key mitochondria-related gene regulating B-cell immune response in periodontitis.

Molecularly imprinted nanogels as synthetic recognition materials for the ultrasensitive detection of periodontal disease biomarkers

Periodontal disease affects supporting dental structures and ranks among one of the top most expensive conditions to treat in the world. Moreover, in recent years, the disease has also been linked to cardiovascular and Alzheimer's diseases. At present, there is a serious lack of accurate diagnostic tools to identify people at severe risk of periodontal disease progression. Porphyromonas gingivalis is often considered one of the most contributing factors towards disease progression. It produces the Arg- and Lys-specific proteases Rgp and Kgp, respectively. Within this work, a short epitope sequence of these proteases is immobilised onto a magnetic nanoparticle platform. These are then used as a template to produce high-affinity, selective molecularly imprinted nanogels, using the common monomers N-tert-butylacrylamide (TBAM), N-isopropyl acrylamide (NIPAM), and N-(3-aminopropyl) methacrylamide hydrochloride (APMA). N,N-Methylene bis(acrylamide) (BIS) was used as a crosslinking monomer to form the interconnected polymeric network. The produced nanogels were immobilised onto a planar gold surface and characterised using the optical technique of surface plasmon resonance. They showed high selectivity and affinity towards their template, with affinity constants of 79.4 and 89.7 nM for the Rgp and Kgp epitope nanogels, respectively. From their calibration curves, the theoretical limit of detection was determined to be 1.27 nM for the Rgp nanogels and 2.00 nM for the Kgp nanogels. Furthermore, they also showed excellent selectivity against bacterial culture supernatants E8 (Rgp knockout), K1A (Kgp knockout), and W50-d (wild-type) strains in complex medium of brain heart infusion (BHI).

Periodontal inflammation as a potential driver of HIV low level viremia

HIV can be successfully suppressed to undetectable levels by antiretroviral therapy (ART) in most people with HIV (PWH). However, a small proportion continues to have persistent low-level viremia (LLV) during ART. A presumed source of LLV is production or replication from viral reservoirs, which are maintained in the presence of ART. It is unknown whether the oral cavity can be considered an HIV reservoir. As periodontal inflammation is a common problem in PWH, we hypothesize that periodontal inflammation in the oral cavity activates (latently) infected cells and thus might be associated with LLV. We included 11 individuals with HIV LLV, and compared HIV-RNA levels in saliva and plasma at baseline and at week 24 after switch of ART. We compared the LLV-group at baseline with 11 age-matched controls with suppressed viremia. To investigate the severity of periodontitis we used Periodontal Inflamed Surface Areas (PISA) by measuring probing depth, gingival recession, bleeding on probing and clinical attachment level. Severity of periodontitis was classified according to the CDC-AAP case definition. Additional insights in periodontal inflammation were obtained by comparing immune activation markers and the presence of periodontal pathogens. In four individuals of the LLV group, residual levels of HIV-RNA were detected in saliva at baseline (N = 1) or at week 24 (N = 2) or both (N = 1). Of the four individuals with LLV, three had residual levels of HIV-RNA in saliva. All 22 individuals had moderate to severe periodontitis. PISA was not significantly different between cases with LLV and controls. Similarly, periodontal pathogens were frequently observed in both groups. Total activated HLA-DR+CD38+ CD4+ cells and CD8+ cells were significantly higher in the LLV group than in the control group (p = <0.01). No immune markers were associated with LLV. In conclusion, periodontal inflammation is an unlikely driver of HIV LLV compared to HIV suppressed individuals.

Bacteria of healthy periodontal tissues as candidates of probiotics: a systematic review

OBJECTIVES

The use of probiotics could promote the balance of the subgingival microbiota to contribute to periodontal health. This study aimed to identify the potential of bacteria commonly associated with healthy periodontal tissues as probiotic candidates.

MATERIAL AND METHODS

A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the PubMed, Scopus, Science Direct, ProQuest, and Ovid databases as well as the combination of Medical Subject Headings (MeSH) and non-MeSH terms. Based on the selection criteria, original studies published in English and identifying the microorganisms present in the periodontium of healthy individuals and patients with periodontitis using the high-throughput 16S ribosomal gene sequencing technique were included.

RESULTS

Out of 659 articles, 12 met the criteria for this review. These articles were published from 2012 to 2020 and mainly originated from the United States, China, and Spain. Most of these studies reported adequate criteria for selecting participants, using standardized clinical criteria, and compliance with quality based on the tools used. In periodontal healthy tissue were identified species like Actinomyces viscosus, Actinomyces naeslundii, Haemophilus parainfluenzae, Rothia dentocariosa, Streptococcus sanguinis, Streptococcus mitis, Streptococcus oralis, Streptococcus gordonii, Streptococcus intermedius, and Prevotella nigrescens which have recognized strains with a capacity to inhibit periodontopathogens.

CONCLUSIONS

S. sanguinis, S. oralis, S. mitis, and S. gordonii are among the bacterial species proposed as potential probiotics because some strains can inhibit periodontopathogens and have been reported as safe for humans.

Long intergenic non-coding RNA 01126 activates IL-6/JAK2/STAT3 pathway to promote periodontitis pathogenesis

OBJECTIVES

Periodontitis seriously affects oral-related quality of life and overall health. Long intergenic non-coding RNA 01126 (LINC01126) is aberrantly expressed in periodontitis tissues. This study aimed to explore the possible pathogenesis of LINC01126 in periodontitis.

METHODS

Inflammatory model of human gingival fibroblasts (HGFs) was established. Cell Counting Kit-8 (CCK-8), wound healing assay, and flow cytometry were utilized to detect biological roles of LINC01126. Binding site of miR-655-3p to LINC01126 and IL-6 was predicted. Then, subcellular localization of LINC01126 and the binding ability of miR-655-3p to LINC01126 and IL-6 in HGFs were verified. Hematoxylin-Eosin (H&E) staining and immunohistochemistry (IHC) staining were utilized to detect tissue morphology and proteins expression of clinical samples.

RESULTS

LINC01126 silencing can alleviate cell inflammation induced by lipopolysaccharide derived from Porphyromonas gingivalis, reduce cell apoptosis, and promote cell migration. As a "sponge" for miR-655-3p, LINC01126 inhibits its binding to mRNA of IL-6, thereby promoting inflammation progression and JAK2/STAT3 pathway activation. Quantitative real-time PCR, Western Blot, and IHC results of clinical tissue samples further confirmed that miR-655-3p expression was down-regulated and IL-6/JAK2/STAT3 was abnormally activated in periodontitis tissues.

CONCLUSIONS

In summary, serving as an endogenous competitive RNA of miR-655-3p, LINC01126 promotes IL-6/JAK2/STAT3 pathway activation, thereby promoting periodontitis pathogenesis.

Exploring gut microbiota's role in rheumatic valve disease: insights from a Mendelian randomization study and mediation analysis

Background

Investigating the relationship between gut microbiota and Rheumatic Valve Disease (RVD) is crucial for understanding the disease's etiology and developing effective interventions. Our study adopts a novel approach to examine the potential causal connections between these factors.

Methods

Utilizing a two-sample Mendelian Randomization (MR) framework, we incorporated a multi-variable MR (MVMR) strategy to assess the mediatory mechanisms involved. This approach involved analyzing data from the MiBioGen consortium for gut microbiota and the FinnGen for RVD, among other sources. Instrumental variables (IVs) were carefully selected based on rigorous MR principles, and statistical analysis was conducted using bidirectional two-sample MR, such as inverse variance-weighted (IVW), weighted median, MR-Egger regression and MR Steiger Test methods. The MR-PRESSO strategy was employed for outlier detection, and MVMR was used to untangle the complex relationships between multiple microbiota and RVD.

Results

Our analysis highlighted several gut microbiota classes and families with potential protective effects against RVD, including Lentisphaerae, Alphaproteobacteria, and Streptococcaceae. In contrast, certain genera, such as Eubacterium eligens and Odoribacter, were identified as potential risk factors. The MVMR analysis revealed significant mediation effects of various immune cell traits and biomarkers, such as CD4-CD8- T cells, CD3 on Terminally Differentiated CD8+ T cell and Pentraxin-related protein PTX, elucidating the complex pathways linking gut microbiota to RVD.

Conclusion

This study underscores the intricate and potentially causal relationship between gut microbiota and RVD, mediated through a range of immune and hormonal factors. The use of MVMR in our methodological approach provides a more comprehensive understanding of these interactions, highlighting the gut microbiota's potential as therapeutic targets in RVD management. Our findings pave the way for further research to explore these complex relationships and develop targeted interventions for RVD.

TPG-functionalized PLGA/PCL nanofiber membrane facilitates periodontal tissue regeneration by modulating macrophages polarization via suppressing PI3K/AKT and NF-κB signaling pathways

Traditional fibrous membranes employed in guided tissue regeneration (GTR) in the treatment of periodontitis have limitations of bioactive and immunomodulatory properties. We fabricated a novel nTPG/PLGA/PCL fibrous membrane by electrospinning which exhibit excellent hydrophilicity, mechanical properties and biocompatibility. In addition, we investigated its regulatory effect on polarization of macrophages and facilitating the regeneration of periodontal tissue both in vivo and in vitro. These findings showed the 0.5%TPG/PLGA/PCL may inhibit the polarization of RAW 264.7 into M1 phenotype by suppressing the PI3K/AKT and NF-κB signaling pathways. Furthermore, it directly up-regulated the expression of cementoblastic differentiation markers (CEMP-1 and CAP) in periodontal ligament stem cells (hPDLSCs), and indirectly up-regulated the expression of cementoblastic (CEMP-1 and CAP) and osteoblastic (ALP, RUNX2, COL-1, and OCN) differentiation markers by inhibiting the polarization of M1 macrophage. Upon implantation into a periodontal bone defect rats model, histological assessment revealed that the 0.5%TPG/PLGA/PCL membrane could regenerate oriented collagen fibers and structurally intact epithelium. Micro-CT (BV/TV) and the expression of immunohistochemical markers (OCN, RUNX-2, COL-1, and BMP-2) ultimately exhibited satisfactory regeneration of alveolar bone, periodontal ligament. Overall, 0.5%TPG/PLGA/PCL did not only directly promote osteogenic effects on hPDLSCs, but also indirectly facilitated cementoblastic and osteogenic differentiation through its immunomodulatory effects on macrophages. These findings provide a novel perspective for the development of materials for periodontal tissue regeneration.

Porphyromonas gingivalis interaction with Candida albicans allows for aerobic escape, virulence and adherence

In the oral cavity Candida albicans interacts with many oral bacteria, including Porphyromonas gingivalis, both physically and metabolically. The aim of this in vitro study was to characterize these interactions and study their effects on the survival of P. gingivalis. First, metabolic interactions were evaluated by counting the colony forming units (CFU) after co-culturing. The results indicated that the anaerobic bacterium P. gingivalis survives under aerobic conditions when co-cultured with C. albicans. This is due to the oxygen consumption by C. albicans as determined by a reduction in survival upon the addition of Antimycin A. By measuring the protease activity, it was found that the presence of C. albicans induced gingipain activity by P. gingivalis, which is an important virulence factor. Adherence of P. gingivalis to hyphae of C. albicans was observed with a dynamic flow system. Using various C. albicans mutants, it was shown that the mechanism of adhesion was mediated by the cell wall adhesins, members of the agglutinin-like sequence (Als) family: Als3 and Als1. Furthermore, the two microorganisms could be co-cultured into forming a biofilm in which P. gingivalis can survive under aerobic culturing conditions, which was imaged using scanning electron microscopy. This study has further elucidated mechanisms of interaction, virulence acquisition and survival of P. gingivalis when co-cultured with C. albicans. Such survival could be essential for the pathogenicity of P. gingivalis in the oxygen-rich niches of the oral cavity. This study has emphasized the importance of interaction between different microbes in promoting survival, virulence and attachment of pathogens, which could be essential in facilitating penetration into the environment of the host.

Influence of periodontal status on patients undergoing hematopoietic stem cell transplantation: A retrospective analysis

Objective

This retrospective analysis aimed to evaluate the prevalence of periodontitis in patients undergoing hematopoietic stem cell transplantation, and investigate the effects of various periodontal statuses and risk factors on oral infection incidence.

Study design

Medical records of patients pre- and post-hematopoietic stem cell transplantation from June 2019 to October 2021were reviewed. The study examined the effort of different periodontal statuses on oral complications and infections in patients during transplantation.

Results

Of 549 transplant patients studied, 363 had periodontitis. Patients with or without periodontitis showed significant differences in mean age, male proportion, and mucositis incidence during transplantation (P < 0.05). Bacteremia rates were slightly higher in patients with periodontitis, but not significant. Male proportion, age, and hospitalization duration significantly increased with advancing periodontitis stages. Only two patients experienced periodontal complications, that were effectively managed and did not interfere in the grafting process.

Conclusion

Periodontitis is prevalent in patients with hematopoietic diseases. Despite its association with oral mucositis, the occurrence of periodontal infection remains low and controllable.

The oral organ: A new vision of the mouth as a whole for a gerophysiological approach to healthy aging

This article brings a new perspective on oral physiology by presenting the oral organ as an integrated entity within the entire organism and its surrounding environment. Rather than considering the mouth solely as a collection of discrete functions, this novel approach emphasizes its role as a dynamic interphase, supporting interactions between the body and external factors. As a resilient ecosystem, the equilibrium of mouth ecological niches is the result of a large number of interconnected factors including the heterogeneity of different oral structures, diversity of resources, external and internal pressures and biological actors. The manuscript seeks to deepen the understanding of age-related changes within the oral cavity and throughout the organism, aligning with the evolving field of gerophysiology. The strategic position and fundamental function of the mouth make it an invaluable target for early prevention, diagnosis, treatment, and even reversal of aging effects throughout the entire organism. Recognizing the oral cavity capacity for sensory perception, element capture and information processing underscores its vital role in continuous health monitoring. Overall, this integrated understanding of the oral physiology aims at advancing comprehensive approaches to the oral healthcare and promoting broader awareness of its implications on the overall well-being.

Far-ultraviolet irradiation at 222 nm destroys and sterilizes the biofilms formed by periodontitis pathogens

BACKGROUND

Periodontal disease is the leading cause of tooth loss, and an association between periodontal disease and non-oral systemic diseases has been shown. Formation of biofilm by periodontal pathogens such as Fusobacterium nucleatum, Porphyromonas gingivalis, and Streptococcus mutans and their resistance to antimicrobial agents are at the root of persistent and chronic bacterial infections.

METHODS

The bactericidal effect of far-ultraviolet (F-UV) light irradiation at 222 nm on periodontal bacteria was assessed qualitatively and quantitatively. The effect of biofilm disruption by F-UV light on periodontal bacteria was examined by crystal violet staining, and the morphologic changes of the biofilm after F-UV irradiation were explored by confocal laser microscopy and scanning electron microscopy. We developed a thin fiber-type 222 nm F-UV irradiator and studied its safety and effect of reducing bacteria in rodent models.

RESULTS

F-UV light at 222 nm had a bactericidal effect on F. nucleatum, P. gingivalis, and S. mutans. Irradiation with F-UV light reduced the biofilm formed by the bacteria and sterilized them from within. Confocal laser microscopy showed a clear reduction in biofilm thickness, and scanning electron microscopy confirmed disintegration of the biofilm architecture. F-UV irradiation was less damaging to DNA and less cytotoxic than deep-ultraviolet light, and it reduced bacterial counts on the tooth surface.

CONCLUSION

F-UV irradiation has the potential to destroy biofilm and act as a bactericide against pathogenic bacteria in the biofilm.

Bioactive injectable mucoadhesive thermosensitive natural polymeric hydrogels for oral bone and periodontal regeneration

Periodontitis is an inflammation-related condition, caused by an infectious microbiome and host defense that causes damage to periodontium. The natural processes of the mouth, like saliva production and eating, significantly diminish therapeutic medication residency in the region of periodontal disease. Furthermore, the complexity and diversity of pathological mechanisms make successful periodontitis treatment challenging. As a result, developing enhanced local drug delivery technologies and logical therapy procedures provides the foundation for effective periodontitis treatment. Being biocompatible, biodegradable, and easily administered to the periodontal tissues, hydrogels have sparked substantial an intense curiosity in the discipline of periodontal therapy. The primary objective of hydrogel research has changed in recent years to intelligent thermosensitive hydrogels, that involve local adjustable sol-gel transformations and regulate medication release in reaction to temperature, we present a thorough introduction to the creation and efficient construction of new intelligent thermosensitive hydrogels for periodontal regeneration. We also address cutting-edge smart hydrogel treatment options based on periodontitis pathophysiology. Furthermore, the problems and prospective study objectives are reviewed, with a focus on establishing effective hydrogel delivery methods and prospective clinical applications.

Periodontopathogen-Related Cell Autophagy-A Double-Edged Sword

The periodontium is a highly organized ecosystem, and the imbalance between oral microorganisms and host defense leads to periodontal diseases. The periodontal pathogens, mainly Gram-negative anaerobic bacteria, colonize the periodontal niches or enter the blood circulation, resulting in periodontal tissue destruction and distal organ damage. This phenomenon links periodontitis with various systemic conditions, including cardiovascular diseases, malignant tumors, steatohepatitis, and Alzheimer's disease. Autophagy is an evolutionarily conserved cellular self-degradation process essential for eliminating internalized pathogens. Nowadays, increasing studies have been carried out in cells derived from periodontal tissues, immune system, and distant organs to investigate the relationship between periodontal pathogen infection and autophagy-related activities. On one hand, as a vital part of innate and adaptive immunity, autophagy actively participates in host resistance to periodontal bacterial infection. On the other, certain periodontal pathogens exploit autophagic vesicles or pathways to evade immune surveillance, therefore achieving survival within host cells. This review provides an overview of the autophagy process and focuses on periodontopathogen-related autophagy and their involvements in cells of different tissue origins, so as to comprehensively understand the role of autophagy in the occurrence and development of periodontal diseases and various periodontitis-associated systemic illnesses.

Effects of Oleanolic Acid Derived from Wine Pomace on Periodontopathic Bacterial Growth in Healthy Individuals: A Randomized Placebo-Controlled Study

Periodontal disease is caused by oral pathogenic bacteria and is associated with systemic disease and frailty. Therefore, its prevention is crucial in extending healthy life expectancy. This study aimed to evaluate the effect of orally administered oleanolic acid, extracted from wine pomace, on periodontopathic bacterial growth in healthy individuals. In this randomized, placebo-controlled, double-blind, parallel-group comparison study, 84 healthy adults were assigned to a placebo (n = 29), low-dose (n = 29, 9 mg oleanolic acid), or high-dose (n = 26, 27 mg oleanolic acid) groups. The number of oral bacteria in their saliva, collected before and 5 h after administration, was determined using the polymerase chain reaction-invader technique. The proportion of periodontopathic bacteria among the total oral bacteria in the saliva was calculated. Oleanolic acid significantly decreased the proportion of Porphyromonas gingivalis among the total oral bacteria in a dose-dependent manner (p = 0.005 (low-dose) and p = 0.003 (high-dose) vs. placebo, Williams' test). Moreover, high-dose oleanolic acid decreased the proportion of Tannerella forsythia (p = 0.064 vs. placebo, Williams' test). Periodontopathic bacteria are closely associated with the development and progression of periodontal disease; thus, the continuous daily intake of oleanolic acid derived from pomace may be helpful in maintaining a healthy oral microbiome by controlling the proportion of periodontopathic bacteria.

Lactobacillus rhamnosus inhibits osteoclast differentiation by suppressing the TLR2/NF-κB pathway

OBJECTIVE

This study aimed to investigate the role of ultrasonicated Lactobacillus rhamnosus extract in osteoclast differentiation and its underlying mechanism, providing new strategies for the treatment of periodontitis.

MATERIALS AND METHODS

Osteoclasts were induced using macrophage colony-stimulating factor and receptor activator for nuclear factor-κB ligand. Lactobacillus rhamnosus extracts were obtained via ultrasonic crushing and ultracentrifugation. The effects of the LGG extract on osteoclast differentiation were evaluated, and the related signaling pathways were examined using western blotting. A mouse periodontitis model was established, and Lactobacillus rhamnosus extract was injected into the gingival sulcus to evaluate the inhibitory effect of Lactobacillus rhamnosus extract on alveolar bone resorption.

RESULTS

At 50 μg/mL, Lactobacillus rhamnosus extract inhibited osteoclast differentiation with no effect on apoptosis and proliferation. This phenomenon was achieved by deactivating the NF-κB/c-Fos/NFATc1 signaling pathway through toll-like receptor 2. The in vivo results showed that the local injection of Lactobacillus rhamnosus extract suppressed osteoclast differentiation and alveolar bone resorption.

CONCLUSION

The ultrasonicated extract of Lactobacillus rhamnosus inhibited osteoclast differentiation by suppressing the activation of the NF-κB/c-Fos/NFATc1 pathway. Furthermore, it inhibited the destruction of the alveolar bone, providing a new strategy for the use of probiotics in the treatment of periodontitis.

Antibacterial activity of lysozyme-chitosan oligosaccharide conjugates on two periodontal bacteria

OBJECTIVE

This study aimed to evaluate the in vitro antibacterial effects of lysozyme-chitosan oligosaccharide conjugates (LYZOX) against Streptococcus gordonii and Porphyromonas gingivalis.

MATERIALS AND METHODS

Planktonic S. gordonii and P. gingivalis were treated with various concentrations of LYZOX for 10 min. The treated bacteria were incubated on trypticase soy agar plates, and colony-forming unit (CFU) was calculated. The antibacterial effect of LYZOX was compared with that of lysozyme, chitosan, physiological saline, and benzalkonium chloride solution. Cell morphology before and after LYZOX treatment was observed using a scanning electron microscope (SEM). The antibacterial effect of LYZOX with decanoic acid against the biofilm-like bacteria was also examined via crystal violet staining. The Kruskal-Wallis test and post hoc Dunn tests were performed to compare the difference in antibacterial activity of each treatment.

RESULTS

Bacterial CFU numbers were reduced after LYZOX treatment in a concentration-dependent manner. The reduction in CFUs was smaller for corresponding concentrations of chitosan or lysozyme alone. SEM analyses revealed bacterial cells shrank following LYZOX treatment. The combined use of LYZOX and decanoic acid yielded an even higher antibacterial effect against bacterial biofilms.

CONCLUSION

LYZOX exhibits antibacterial activity against two periodontal bacteria and may be a promising plaque control agent.

SARS-CoV-2, periodontal pathogens, and host factors: The trinity of oral post-acute sequelae of COVID-19

COVID-19 as a pan-epidemic is waning but there it is imperative to understand virus interaction with oral tissues and oral inflammatory diseases. We review periodontal disease (PD), a common inflammatory oral disease, as a driver of COVID-19 and oral post-acute-sequelae conditions (PASC). Oral PASC identifies with PD, loss of teeth, dysgeusia, xerostomia, sialolitis-sialolith, and mucositis. We contend that PD-associated oral microbial dysbiosis involving higher burden of periodontopathic bacteria provide an optimal microenvironment for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. These pathogens interact with oral epithelial cells activate molecular or biochemical pathways that promote viral adherence, entry, and persistence in the oral cavity. A repertoire of diverse molecules identifies this relationship including lipids, carbohydrates and enzymes. The S protein of SARS-CoV-2 binds to the ACE2 receptor and is activated by protease activity of host furin or TRMPSS2 that cleave S protein subunits to promote viral entry. However, PD pathogens provide additional enzymatic assistance mimicking furin and augment SARS-CoV-2 adherence by inducing viral entry receptors ACE2/TRMPSS, which are poorly expressed on oral epithelial cells. We discuss the mechanisms involving periodontopathogens and host factors that facilitate SARS-CoV-2 infection and immune resistance resulting in incomplete clearance and risk for 'long-haul' oral health issues characterising PASC. Finally, we suggest potential diagnostic markers and treatment avenues to mitigate oral PASC.

Oral health as a modifiable risk factor for cardiovascular diseases

Cardiovascular diseases (CVDs) are a leading cause of morbidity and mortality worldwide with a high socioeconomic burden. Increasing evidence supports a convincing connection with increased cardiovascular risk of periodontal diseases (PD), a group of widespread, debilitating, and costly dysbiotic relapsing-remitting inflammatory diseases of the tissues supporting the teeth. Herein, we ensembled the best available evidence on the connection between CVDs and PD to review the recently emerging concept of the latter as a non-traditional risk factor for CVDs. We focused on oral dysbiosis, inflammation-associated molecular and cellular mechanisms, and epigenetic changes as potential causative links between PD and CVDs. The available evidence on the effects of periodontal treatment on cardiovascular risk factors and diseases was also described.

Tooth Loss and Chronic Pain: A Population-based Analysis of the National Health and Nutrition Examination Survey

Poor oral health conditions in adults are associated with chronic pain. A nationwide cross-sectional study was conducted to investigate the link between tooth loss and chronic pain. The study involved 8,662 participants from the National Health and Nutrition Examination Survey. Tooth count was categorized into 4 groups, and chronic pain was defined as persistent pain lasting over 3 months despite treatment. Location of the chronic pain, demographics, comorbidities, lifestyle determinants, and dietary intake were retrieved. Univariate and multivariate logistic regression were used to explore cross-sectional associations between tooth count and chronic pain. Compared to participants with more than 20 teeth, those with severe tooth loss presented greater odds of chronic pain (adjusted odds ratio [aOR] = 2.111, 95% confidence intervals (CI) = 1.213-3.676 for patients with 1-8 teeth). Edentulous participants presented with significantly higher odds of chronic pain in the lower extremities (78.4%) and buttocks (49.5%). In the multivariate model, apart from rheumatic arthritis (aOR = 4.004, 95% CI = 2.766-5.798), variables of higher chronic pain included smoking (aOR = 1.518, 95% CI = 1.228-1.878), and hypertension (aOR = 1.463, 95% CI = 1.013-2.112). On the contrary, being Mexican American (aOR = .603, 95% CI = .414-.880) was associated with lower odds of chronic pain. The findings suggested a significant link between chronic pain and tooth loss, independent of ethnicity, lifestyle determinants, and immune-mediated inflammatory diseases including rheumatoid arthritis. PERSPECTIVE: A U.S. nationwide study examined tooth loss and chronic pain. Those with severe tooth loss had increased odds of chronic pain. Edentulous individuals presented higher odds of pain in lower extremities and buttocks. This study highlighted the link between tooth loss and chronic pain, independent of comorbidities and lifestyle factors.

Effect of prolonged hospitalization on the maintenance of oral health: A self-report survey

OBJECTIVES

This study aims to evaluate the effect of prolonged hospitalization on the maintenance of dental health and to assess the nursing staff's approach to addressing these concerns.

METHODS

A survey questionnaire explored changes in the routine dental care of patients hospitalized for over a month. The involvement of nursing staff in addressing dental care was also evaluated.

RESULTS

Fifty adult patients aged 18-89 years (mean age 62.4 ± 20.54 years), 27 (54%) males, completed the survey. During hospitalization (mean 58.59 ± 38.63 days) 26% and 18%, increased consumption of sweets and sugary beverages, between meals, respectively; 26% and 20% of the patients reduced the frequency of tooth brushing in the morning and in the evening, respectively, and 42.2% of them, reduced the quality of their toothbrushing during hospitalization. Nevertheless, 95.9% and 93.9% of them were never instructed during hospitalization to limit their consumption of sweets and sugary beverages and 83.3% and 62.5% of them had never been reminded or offered assistance during hospitalization in performing toothbrushing, respectively. The lower frequency of morning toothbrushing was significantly correlated with a lack of nurses' assistance (p = 0.004). In contrast, 62.6% reported they were reminded every day to shower. Patients in the rehabilitation and geriatrics departments reported a greater need for a brush/toothpaste (p < 0.0001) and assistance in toothbrushing (p < 0.0001).

CONCLUSIONS

Prolonged hospitalization leads to significant deterioration in inpatients' dental health maintenance. Raising awareness among nurses regarding their inpatient's oral health maintenance is warranted. Providing patients with toothbrushes, toothpaste and educational materials upon hospitalization is recommended.

Comparative analysis of microbial composition and functional characteristics in dental plaque and saliva of oral cancer patients

BACKGROUND

The oral cavity is home to various ecological niches, each with its own unique microbial composition. Understanding the microbial communities and gene composition in different ecological niches within the oral cavity of oral cancer (OC) patients is crucial for determining how these microbial populations contribute to disease progression.

METHODS

In this study, saliva and dental plaque samples were collected from patients with OC. Metagenomic sequencing was employed to analyze the microbial community classification and functional composition of the different sample groups.

RESULTS

The results of the study revealed significant differences in both the function and classification of microbial communities between saliva and dental plaque samples. The diversity of microbial species in saliva was found to be higher compared to  that in plaque samples. Notably, Actinobacteria were enriched in the dental plaque of OC patients. Furthermore, the study identified several inter-group differential marker species, including Prevotella intermedia, Haemophilus parahaemolyticus, Actinomyces radius, Corynebacterium matruchitii, and Veillonella atypica. Additionally, 1,353 differential genes were annotated into 23 functional pathways. Interestingly, a significant correlation was observed between differentially labeled species and Herpes simplex virus 1 (HSV-1) infection, which may be related to the occurrence and development of cancer.

CONCLUSIONS

Significant differences in the microbial and genetic composition of saliva and dental plaque samples were observed in OC patients. Furthermore, pathogenic bacteria associated with oral diseases were predominantly enriched in saliva. The identification of inter-group differential biomarkers and pathways provide insights into the relationship between oral microbiota and the occurrence and development of OC.

Migraine and the microbiota. Can probiotics be beneficial in its prevention? - a narrative review

Migraine is a recurrent disease of the central nervous system that affects an increasing number of people worldwide causing a continuous increase in the costs of treatment. The mechanisms underlying migraine are still unclear but recent reports show that people with migraine may have an altered composition of the intestinal microbiota. It is well established that the gut-brain axis is involved in many neurological diseases, and probiotic supplementation may be an interesting treatment option for these conditions. This review collects data on the gastrointestinal and oral microbiota in people suffering from migraine and the use of probiotics as a novel therapeutic approach in its treatment.

Frankincense (Boswellia serrata) Extract Effects on Growth and Biofilm Formation of Porphyromonas gingivalis, and Its Intracellular Infection in Human Gingival Epithelial Cells

Frankincense is produced by Boswellia trees, which can be found throughout the Middle East and parts of Africa and Asia. Boswellia serrata extract has been shown to have anti-cancer, anti-inflammatory, and antimicrobial effects. Periodontitis is an oral chronic inflammatory disease that affects nearly half of the US population. We investigated the antimicrobial effects of B. serrata extract on two oral pathogens associated with periodontitis. Using the minimum inhibitory concentration and crystal violet staining methods, we demonstrated that Porphyromonas gingivalis growth and biofilm formation were impaired by treatment with B. serrata extracts. However, the effects on Fusobacterium nucleatum growth and biofilm formation were not significant. Using quantification of colony-forming units and microscopy techniques, we also showed that concentrations of B. serrata that were not toxic for host cells decreased intracellular P. gingivalis infection in human gingival epithelial cells. Our results show antimicrobial activity of a natural product extracted from Boswellia trees (B. serrata) against periodontopathogens. Thus, B. serrata has the potential for preventing and/or treating periodontal diseases. Future studies will identify the molecular components of B. serrata extracts responsible for the beneficial effects.

Periodontitis exacerbates pulmonary hypertension by promoting IFNγ+ T cell infiltration in mice

Uncovering the risk factors of pulmonary hypertension and its mechanisms is crucial for the prevention and treatment of the disease. In the current study, we showed that experimental periodontitis, which was established by ligation of molars followed by orally smearing subgingival plaques from patients with periodontitis, exacerbated hypoxia-induced pulmonary hypertension in mice. Mechanistically, periodontitis dysregulated the pulmonary microbiota by promoting ectopic colonization and enrichment of oral bacteria in the lungs, contributing to pulmonary infiltration of interferon gamma positive (IFNγ+) T cells and aggravating the progression of pulmonary hypertension. In addition, we identified Prevotella zoogleoformans as the critical periodontitis-associated bacterium driving the exacerbation of pulmonary hypertension by periodontitis, and the exacerbation was potently ameliorated by both cervical lymph node excision and IFNγ neutralizing antibodies. Our study suggests a proof of concept that the combined prevention and treatment of periodontitis and pulmonary hypertension are necessary.

Oral and gut microbial profiling in periodontitis and Parkinson's disease

Objectives

We tested the hypothesis that Parkinson's disease (PA) alters the periodontitis-associated oral microbiome.

Method

Patients with periodontitis with Parkinson's disease (PA+P) and without PA (P) and systemically and periodontally healthy individuals (HC) were enrolled. Clinical, periodontal and neurological parameters were recorded. The severity of PA motor functions was measured. Unstimulated saliva samples and stool samples were collected. Next-generation sequencing of 16S ribosomal RNA (V1-V3 regions) was performed.

Results

PA patients had mild-to-moderate motor dysfunction and comparable plaque scores as those without, indicating that oral hygiene was efficient in the PA+P group. In saliva, there were statistically significant differences in beta diversity between HC and PA+P (p = 0.001), HC and P (p = 0.001), and P and PA+P (p = 0.028). The microbial profiles of saliva and fecal samples were distinct. Mycoplasma faucium, Tannerella forsythia, Parvimonas micra, and Saccharibacteria (TM7) were increased in P; Prevotella pallens, Prevotella melaninogenica, Neisseria multispecies were more abundant in PA+P group, Ruthenibacterium lactatiformans, Dialister succinatiphilus, Butyrivibrio crossotus and Alloprevotella tannerae were detected in fecal samples in P groups compared to healthy controls.

Conclusions

No significant differences were detected between Parkinson's and non-Parkinson's gut microbiomes, suggesting that Parkinson's disease modifies the oral microbiome in periodontitis subjects independent of the gut microbiome.

Mediterranean diet: a potential player in the link between oral microbiome and oral diseases

Background

The oral microbiome is a complex and dynamic assemblage of microorganisms that colonize different sites of the oral cavity maintaining both oral and systemic health. Therefore, when its composition is altered, oral diseases occur. Among oral inflammatory pathologies, periodontal diseases affect the tissues surrounding the teeth, representing the main cause of tooth loss and one of the most important threats to the oral health. Lifestyle and eating habits influence the composition of the human oral microbiota and the development and progression of oral diseases. In this context, the Mediterranean Diet (MD) model, comprising both healthy dietary choices and lifestyle, is linked to the prevention of several metabolic and chronic-degenerative pathological processes, including oral diseases. Indeed, the MD is a plant-based diet, enriched of anti-inflammatory and antioxidant nutrients, which may induce beneficial effects against dental caries and periodontal diseases.

Aim

This review summarizes the role of the oral microbiome in the development of the oral diseases and the potential of MD in modulating the oral microbiome leading to implications for oral health.

Conclusions

The data collected highlight the need to promote the MD pattern along with the correct hygiene habits to prevent the development of oral diseases.

YouTube as an information source for bleeding gums: A quantitative and qualitative analysis

Gum bleeding is a common dental problem, and numerous patients seek health-related information on this topic online. The YouTube website is a popular resource for people searching for medical information. To our knowledge, no recent study has evaluated content related to bleeding gums on YouTube™. Therefore, this study aimed to conduct a quantitative and qualitative analysis of YouTube videos related to bleeding gums. A search was performed on YouTube using the keyword "bleeding gums" from Google Trends. Of the first 200 results, 107 videos met the inclusion criteria. The descriptive statistics for the videos included the time since upload, the video length, and the number of likes, views, comments, subscribers, and viewing rates. The global quality score (GQS), usefulness score, and DISCERN were used to evaluate the video quality. Statistical analysis was performed using the Kruskal-Wallis test, Mann-Whitney test, and Spearman correlation analysis. The majority (n = 69, 64.48%) of the videos observed were uploaded by hospitals/clinics and dentists/specialists. The highest coverage was for symptoms (95.33%). Only 14.02% of the videos were classified as "good". The average video length of the videos rated as "good" was significantly longer than the other groups (p <0.05), and the average viewing rate of the videos rated as "poor" (63,943.68%) was substantially higher than the other groups (p <0.05). YouTube videos on bleeding gums were of moderate quality, but their content was incomplete and unreliable. Incorrect and inadequate content can significantly influence patients' attitudes and medical decisions. Effort needs to be expended by dental professionals, organizations, and the YouTube platform to ensure that YouTube can serve as a reliable source of information on bleeding gums.

Oral infection with Porphyromonas gingivalis augmented gingival epithelial barrier molecules alteration with aging

OBJECTIVE

Disruption of the gingival epithelial barrier is often mediated by aging or the pathogen Porphyromonas gingivalis. This study examined the combined effects of aging and P. gingivalis exposure on gingival epithelial barrier molecules.

METHODS

In vitro experiments involved treating young- and senescence-induced primary human gingival epithelial progenitor cells (HGEPp) with P. gingivalis lipopolysaccharide (LPS). Transepithelial electrical resistance (TER) and paracellular permeability were measured. In vivo, male C57BL/6J mice aged 10 (young) and 80 (old) weeks were divided into four groups: young, old, young with P. gingivalis (Pg-Young) inoculation, and old with P. gingivalis (Pg-Old) inoculation. P. gingivalis was inoculated orally thrice a week for 5 weeks. The mice were sacrificed 30 days after the last inoculation, and samples were collected for further procedures. The junctional molecules (Claudin-1, Claudin-2, E-cadherin, and Connexin) were analyzed for mRNA expression using qRT-PCR and protein production using western blotting and immunohistochemistry. The alveolar bone loss and inflammatory cytokine levels in gingival tissues were also assessed.

RESULTS

LPS-treated senescent cells exhibited a pronounced reduction in TER, increased permeability to albumin protein, significant upregulation of Claudin-1 and Claudin-2, and significant downregulation of E-cadherin and Connexin. Furthermore, the Pg-Old group showed identical results with aging in addition to an increase in alveolar bone loss, significantly higher than that in the other groups.

CONCLUSION

In conclusion, the host susceptibility to periodontal pathogens increases with age through changes in the gingival epithelial barrier molecules.

A Mendelian Randomisation Analysis Reveals No Relationship Between Periodontitis and Coronary Atherosclerosis

OBJECTIVES

Growing evidence appears to intimate a profound connection between periodontitis and coronary atherosclerosis (CA), yet the existence of a causal relationship remains unclear. Through the implementation of Mendelian randomization analysis, we further evaluated the potential causal link between chronic/acute periodontitis (CP/AP) and CA.

METHODS

Utilizing genome-wide association study (GWAS) summary statistics, we incorporated periodontitis data derived from European samples (n1 = 198,441; n2 = 195,762) and CA data from 61,194 cases. We conducted a 2 sample, bidirectional Mendelian randomization (MR) analysis using the inverse-variance weighted (IVW) method as the main analytical approach. Supplementary analyses were executed through MR Egger, Weighted median (WM), IVW, Simple mode, and Weighted mode approaches.

RESULTS

The IVW analysis revealed no significant causal relationship between CA and periodontitis (CA-CP: OR = 2.110, 95% CI = 0.208-21.317, P = .527; CA-AP: OR = 0.414, 95% CI = 0.051-3.384, P = .644). Similarly, the bidirectional analysis did not identify impact of periodontitis on CA (OR = 1.000, 95% CI = 0.999-1.001, P = .953). The supplementary analyses corroborated these findings.

CONCLUSIONS

While studies highlighting a correlation between periodontitis and CA, our comprehensive analysis does not corroborate a causal association between periodontitis and CA. Further research is needed to elucidate other potential shared mechanisms and causal evidence between periodontitis and CA.

Antibacterial and DNA-Based Hydrogels In Situ Block TNF-α to Promote Diabetic Alveolar Bone Rebuilding

Alveolar bone injury under diabetic conditions can severely impede many oral disease treatments. Rebuilding diabetic alveolar bone in clinics is currently challenging due to persistent infection and inflammatory response. Here, an antibacterial DNA-based hydrogel named Agantigel is developed by integrating silver nanoclusters (AgNCs) and tumor necrosis factor-alpha (TNF-α) antibody into DNA hydrogel to promote diabetic alveolar bone regeneration. Agantigel can effectively inhibit bacterial growth through AgNCs while exhibiting negligible cytotoxicity in vitro. The sustained release of TNF-α antibody from Agantigel effectively blocks TNF-α and promotes M2 polarization of macrophages, ultimately accelerating diabetic alveolar bone regeneration in vivo. After 21 days of treatment, Agantigel significantly accelerates the defect healing rate of diabetic alveolar bone up to 82.58 ± 8.58% and improves trabecular architectures compared to free TNF-α (42.52 ± 15.85%). The results imply that DNA hydrogels are potential bio-scaffolds helping the sustained release of multidrug for treating DABI or other oral diseases.

Porphyromonas gingivalis infection in the oral cavity is associated with elevated galactose-deficient IgA1 and increased nephritis severity in IgA nephropathy

BACKGROUND

The relationship between the major periodontal bacteria, Porphyromonas gingivalis, and the pathogenesis of IgA nephropathy (IgAN)-particularly with respect to galactose-deficient IgA1 (Gd-IgA1)-has not been fully elucidated.

METHODS

Saliva samples from 30 IgAN patients and 44 patients with chronic kidney disease (CKD) were subjected to analysis of P. gingivalis status via polymerase chain reaction using a set of P. gingivalis-specific primers. The associations between P. gingivalis presence and clinical parameters, including plasma Gd-IgA1, were analyzed in each group.

RESULTS

Compared with the CKD group, the IgAN group demonstrated significantly higher plasma Gd-IgA1 levels (p < 0.05). Compared with the P. gingivalis-negative subgroup, the P. gingivalis-positive subgroup exhibited significantly higher plasma Gd-IgA1 levels in both IgAN and CKD patients (p < 0.05). Additionally, among IgAN patients, the P. gingivalis-positive subgroup displayed significantly higher plasma Gd-IgA1 and urine protein levels, compared with the P. gingivalis-negative subgroup (p < 0.05). With respect to renal biopsy findings, the frequencies of segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis were significantly greater in the P. gingivalis-positive subgroup than in the P. gingivalis-negative subgroup, according to the Oxford classification of IgAN (p < 0.05).

CONCLUSION

Our findings suggest an association between the presence of P. gingivalis in the oral cavity and the pathogenesis of IgAN, mediated by increased levels of Gd-IgA1.

Periodontal and Systemic Diseases: A Descriptive Analysis of Awareness Among the General Saudi Population

Background Taking into account the limited availability of research data, this study aimed to determine the general Saudi population's awareness of the link between periodontal diseases and systemic diseases. Methodology A structured online questionnaire with eight awareness items, apart from demographic variables, was distributed through email, WhatsApp, and Telegram to a sample of 500 individuals. The data were analyzed using a simple descriptive statistical approach and interpreted as ratios for comparison. The awareness regarding systemic diseases associated with periodontal diseases was classified into the following four categories based on the Bloom cutoff points: high (>80%), average (60-79%), low (40-59%), and extremely low (<40%). Results A response rate of 68% was reached with the participation of 340 Saudi citizens residing in the Al Qassim region. Overall, 61.22% of research participants had an average awareness of the link between periodontal and systemic diseases. Almost two-thirds (>60%) of participants were aware that periodontal diseases and systemic diseases have an association and that individuals with systemic diseases need a periodontal checkup. A majority (85%) of participants opined that periodontal treatment has the potential to enhance overall health. Nonetheless, only a few participants (60%) were aware of the association between diabetes mellitus and periodontal diseases, and they had a limited awareness of the association with other systemic diseases. Conclusions Although the Saudi general population possesses average awareness about the relationship between periodontal diseases and systemic diseases, their awareness about different systemic diseases and conditions is extremely low, particularly regarding infertility, stroke, and metabolic diseases. The present research indicates a deficiency in the efforts by healthcare professionals, community service providers, and community administrators to educate the general public regarding the association between periodontal diseases and systemic diseases. This awareness is crucial for individuals to control these intricate, interconnected diseases.

Advances in the relationship between periodontopathogens and respiratory diseases (Review)

Periodontitis is a common chronic inflammatory and destructive disease in the mouth and is considered to be associated with systemic diseases. Accumulating evidence has suggested that periodontitis is a risk factor for pulmonary diseases such as pneumonia, chronic obstructive pulmonary disease (COPD), asthma, coronavirus disease 2019 (COVID‑19) and lung cancer. The presence of common periodontal pathogens has been detected in samples from a variety of pulmonary diseases. Periodontal pathogens can be involved in lung diseases by promoting the adhesion and invasion of respiratory pathogens, regulating the apoptosis of respiratory epithelium and inducing overexpression of mucin and disrupting the balance of immune systemin respiratory epithelium cells. Additionally, measures to control plaque and maintain the health of periodontal tissue can decrease the incidence of respiratory adverse events. This evidence suggests a close association between periodontitis and pulmonary diseases. The present study aimed to review the clinical association between periodontitis and pneumonia, COPD, asthma, COVID‑19 and lung cancer, and propose a possible mechanism and potential role of periodontal pathogens in linking periodontal disease and lung disease. This could provide a direction for further research on the association between periodontitis and lung disease and provide novel ideas for the clinical diagnosis and treatment management of these two diseases.

Association between periodontitis and endometriosis: a bidirectional Mendelian randomization study

Introduction

A potential association between periodontitis and endometriosis has been indicated in previous observational studies. Nevertheless, the causal link between these two disorders has not been clarified.

Methods

Based on publicly available genome-wide association study (GWAS) summary datasets, we conducted a bidirectional Mendelian randomization (MR) study to investigate the relationship between periodontitis and endometriosis and its subtypes. Single nucleotide polymorphisms (SNPs) strongly associated with candidate exposures at the genome-wide significance level (P < 5 × 10-8) were selected as instrumental variables (IVs). The inverse variance-weighted regression (IVW) was performed to estimate the causal effect of periodontitis on endometriosis. We further conducted two sensitivity analyses, MR-Egger and weighted median, to test the validity of our findings. The main results were replicated via data from the UK Biobank. Finally, a reverse MR analysis was performed to evaluate the possibility of reverse causality.

Results

The IVW method suggested that periodontitis was positively associated with endometriosis of the pelvic peritoneum (OR = 1.079, 95% CI = 1.016 to 1.146, P = 0.014). No causal association was indicated between periodontitis and other subtypes of endometriosis. In reversed analyses, no causal association between endometriosis or its subtypes and periodontitis was found.

Conclusions

Our study provided genetic evidence on the causal relationship between periodontitis and endometriosis of the pelvic peritoneum. More studies are necessary to explore the underlying mechanisms.

Interplay between dental caries pathogens, periodontal pathogens, and sugar molecules: approaches for prevention and treatment

Globally, oral diseases affect nearly 3.5 billion people, accounting for 4.6% of the healthcare expenditure. Common oral diseases include dental caries and periodontal disease, associated with biofilms formed by cariogenic pathogens. Epidemiological studies associate carbohydrates with these diseases due to  the sugars metabolized by cariogenic pathogens. This review focuses on dental caries and periodontal pathogens, quorum sensing, lectin-carbohydrate interactions, and various sugar molecules. Cariogenic sugars significantly influence biofilms by enhancing pathogen adhesion, viability, and gene expressions associated with biofilm formation. Moreover, lectin-carbohydrate interactions contribute to biofilm stability. Disrupting these interactions is a potential strategy for oral disease prevention. The use of nanoparticles, such as quantum dots, provides novel insights into lectin-sugar interactions and the development of inhibitors. Additionally, nanomaterials like calcium phosphate nanoparticles neutralize acids and inhibit microbial growth. This overview emphasizes understanding the relationships between oral diseases, microbial communities, and sugars to devise preventive and therapeutic strategies against oral diseases.

Oral Lactobacillus zeae exacerbates the pathological manifestation of periodontitis in a mouse model

INTRODUCTION

The worldwide prevalence of periodontitis is considerably high, and its pathogenic mechanisms must be investigated and understood in order to improve clinical treatment outcomes and reduce the disease prevalence and burden. The exacerbation of the host immune system induced by oral microbial dysbiosis and the subsequent tissue destruction are the hallmarks of the periodontitis. However, the oral bacteria involved in periodontitis are not fully understood. We used the Oxford Nanopore Technologies (ONT) sequencing system to analyze metagenomic information in subgingival dental plaque from periodontitis and non-periodontitis patients. The number of Lactobacillus zeae (L. zeae) in the periodontitis patients was 17.55-fold higher than in the non-periodontitis patients, suggesting that L. zeae is a novel periodontitis-associated pathogen. Although several Lactobacillus species are used in vivo as probiotics to treat periodontitis and compete with Porphyromonas gingivalis (P. gingivalis), the roles of L. zeae in periodontitis progression, and the relationship between L. zeae and P. gingivalis needs to be investigated.

METHODS

Both L. zeae and P. gingivalis were inoculated in the ligature-implant site of periodontitis mice. We collected mouse gingival crevicular fluid to analyze inflammatory cytokine secretion using a multiplex assay. Intact or sliced mouse maxilla tissue was used for micro-computed tomography analysis or hematoxylin and eosin staining, immunohistochemistry, and tartrate-resistant acid phosphatase staining to evaluate alveolar bone loss, neutrophil infiltration, and osteoclast activation, respectively.

RESULTS

We observed that L. zeae competed with P. gingivalis, and it increased inflammatory cytokine secretion at the ligature-implant site. Similar to P. gingivalis, L. zeae promoted ligature-induced neutrophile infiltration, osteoclast activation, and alveolar bone loss.

DISCUSSION

We, therefore, concluded that L. zeae accelerated the progression of periodontitis in the ligature-induced periodontitis mouse model.

Measurement of atherosclerosis markers in individuals with periodontitis

PURPOSE

The inflammatory response due to inflammatory cytokines, bacterial pathogens, and the altered lipoprotein metabolism in patients with periodontitis indicates that infection with periodontal anaerobic bacteria may influence atherogenesis in vitro and in vivo. We aimed to explore the effect of periodontitis concerning clinical and ultrasound markers of early atherosclerosis.

METHODS

In this case-control study, a total of 30 systemically healthy adults (15 with periodontitis and 15 without periodontitis) over 40 years of age were studied. Periodontitis was determined by measuring the clinical attachment level (CAL) and radiographic bone loss (RBL). Conventional cardiovascular risk factors, including body mass index, serum levels of total cholesterol (TCH), triglycerides (TG), and high-density and low-density lipoprotein (HDL and LDL, respectively) cholesterol were evaluated. Carotid artery intima-media thickness (IMT) was measured using ultrasonography.

RESULTS

The mean values of the CAL and carotid IMT were 5.02±0.9 mm and 0.084±0.01 cm vs. 1.6±0.61 mm and 0.072±0.02 cm in the periodontitis and healthy groups, respectively, reflecting statistically significant differences (P=0.001 and P=0.037, respectively). There were statistically significant differences in the serum levels of TCH, TG, and LDL between the 2 groups (P=0.017). The CAL and RBL were positively associated with carotid IMT and serum cholesterol levels, except for HDL, whereas tooth loss was not associated with any markers (P<0.05). Compared to the healthy group, participants with periodontitis exhibited 2.09 times higher odds (95% confidence interval, 1.22-3.59) of having subclinical atherosclerosis.

CONCLUSIONS

The presence of periodontitis increased the risk of atherosclerosis.

Antimicrobial activity, surface properties, and cytotoxicity of microencapsulated phytochemicals incorporated into three-dimensionally printable dental polymers

OBJECTIVES

This study aimed to investigate the antimicrobial properties of three dimensionally-printed dental polymers (3DPs) incorporated with microencapsulated phytochemicals (MPs) and to assess their surface characteristics and cytotoxicity.

METHODS

MPs derived from phytoncide oil and their specific chemical components were introduced into suspensions of three microbial species: Streptococcus gordonii, Streptococcus oralis, and Candida albicans. Optical density was measured to determine the microbial growth in the presence of MPs for testing their antimicrobial activity. MPs at 5% (w/w) were mixed with dental polymers and dispersants to 3DP discs. These microbial species were then seeded onto the discs and incubated for 24 h. The antibacterial and antifungal activities of MP-containing 3DPs were evaluated by counting the colony-forming units (n = 3). The biofilm formation on the 3DP was assessed by crystal violet staining assay (n = 3). Microbial viability was determined using a live-dead staining and CLSM observation (n = 3). Surface roughness and water contact angle were assessed (n = 10). Cytotoxicity of MP-containing 3DPs for human gingival fibroblast was evaluated by MTT assay.

RESULTS

MPs, particularly (-)-α-pinene, suppressed the growth of all tested microbial species. MP-containing 3DPs significantly reduced the colony count (P ≤ 0.001) and biofilm formation (P ≤ 0.009), of all tested microbial species. Both surface roughness (P < 0.001) and water contact angle (P < 0.001) increased. The cytotoxicity remained unchanged after incorporating MPs to the 3DPs (P = 0.310).

CONCLUSIONS

MPs effectively controlled the microbial growth on 3DPs as evidenced by the colony count, biofilm formation, and cell viability. Although MPs modified the surface characteristics, they did not influence the cytotoxicity of 3DPs.

CLINICAL SIGNIFICANCE

Integration of MPs into 3DPs could produce dental prostheses or appliances with antimicrobial properties. This approach not only provides a proactive solution to reduce the risk of oral biofilm-related infection but also ensures the safety and biocompatibility of the material, thereby improving dental care.

Effects and mechanisms of Porphyromonas gingivalis outer membrane vesicles induced cardiovascular injury

BACKGROUND

The outer membrane vesicles (OMVs) derived from Porphyromonas gingivalis (P. gingivalis) have long been acknowledged for their crucial role in the initiation of periodontitis. However, the implications of P. gingivalis OMVs in the context of cardiovascular disease (CVD) remain incompletely understood. This study aimed to clarify both the impact and the underlying mechanisms through which P. gingivalis OMVs contribute to the propagation of distal cardiovascular inflammation and trauma.

METHODS

In this study, various concentrations (0, 1.25, 2.5, and 4.5 µg/µL) of P. gingivalis OMVs were microinjected into the common cardinal vein of zebrafish larvae at 48 h post-fertilization (hpf) to assess changes in cardiovascular injury and inflammatory response. Zebrafish larvae from both the PBS and the 2.5 µg/µL injection cohorts were harvested at 30 h post-injection (hpi) for transcriptional analysis. Real-time quantitative PCR (RT-qPCR) was employed to evaluate relative gene expression.

RESULTS

These findings demonstrated that P. gingivalis OMVs induced pericardial enlargement in zebrafish larvae, caused vascular damage, increased neutrophil counts, and activated inflammatory pathways. Transcriptomic analysis further revealed the involvement of the immune response and the extracellular matrix (ECM)-receptor interaction signaling pathway in this process.

CONCLUSION

This study illuminated potential mechanisms through which P. gingivalis OMVs contribute to CVD. It accentuated their involvement in distal cardiovascular inflammation and emphasizes the need for further research to comprehensively grasp the connection between periodontitis and CVD.

Extracellular vesicles-Potential link between periodontal disease and diabetic complications

It has long been suggested that a bidirectional impact exists between periodontitis and diabetes. Periodontitis may affect diabetes glycemic control, insulin resistance, and diabetic complications. Diabetes can worsen periodontitis by delaying wound healing and increasing the chance of infection. Extracellular vesicles (EVs) are heterogeneous particles of membrane-enclosed spherical structure secreted by eukaryotes and prokaryotes and play a key role in a variety of diseases. This review will introduce the biogenesis, release, and biological function of EVs from a microbial and host cell perspective, discuss the functional properties of EVs in the development of periodontitis and diabetes, and explore their role in the pathogenesis and clinical application of these two diseases. Their clinical implication and diagnostic value are also discussed.

Mediators of Periodontitis complementing the development of Neural Disorders

As a common oral health concern, periodontitis has been a source of attention for the global health community because of its linkage with systemic and neurological diseases. The purpose of the present study is to reveal the mediating role of specific cytokines, neuropeptides, and pathogens in the association of chronic periodontitis and neural disorders. To find the related literature different search engines namely PMC, Science Direct, PubMed, Research Gate, and Google Scholar were explored for a study period of five months from October 2022 to February 2023. This review offers a summary of those neuronal diseases that were more related to human behaviors in association with chronic periodontitis. Those neuronal pathologies mainly included Alzheimer's disease, psychosis, stress, anxiety, dementia, Alzheimer's, major depressive disorder, and diabetic peripheral neuropathy, which may otherwise remain subside or even control in the absence of chronic periodontitis and its mediators. Specifically, periodontitis related specific cytokines i.e. IL-6, IL-1, Tumor necrosis factor alpha (TNF-α), C-reactive protein (CRP), and alpha1-antichymotrypsin, neuropeptides such as insulin-like growth factor-2 (IGF-2), neuropeptide Y, substance P, neurokinin A, calcitonin gene-related peptide (CGRP), and vasoactive intestinal polypeptide (VIP), and a polybacterial pathogenic consortium of porphyromonas gingivalis, tannerella forsythia, and treponema denticola, were involved in the mediation and exacerbation of the associated neuronal cognitive pathologies.

Comparative analysis of salivary microbiota in diabetic and non-diabetic individuals of North India using metagenomics

Background

Saliva, an oral secretion is considered an essential biological modulator involved in maintaining oral homeostasis. Increased glucose levels in diabetic patients' saliva may have an impact on diversity of microbes. Comparing the salivary microflora of diabetic and non-diabetic cohorts will help in diagnosis and risk assessment of oral health complications. This will provide greater knowledge about the contribution of oral microbes to the development of oral illnesses. The association between salivary microbiota and diabetic state is less explored in the North Indian population, hence current observational study was performed to analyze the salivary microflora of diabetic and non-diabetic individuals using metagenomic analysis.

Materials and methods

This single-center non-randomized observational trial was conducted in Uttar Pradesh, India. Participants were enrolled into either diabetic (n = 68) or non-diabetic groups (n = 68) based on their diabetes status. Following saliva collection, DNA was extracted and metagenomic sequencing was performed.

Results

Phylum Bacteroidetes and Fusobacteria were significantly abundant in diabetic individuals (p < 0.0001), while Proteobacteria was significantly higher among non-diabetic individuals (p < 0.0001). No statistical difference in phylum Actinobacteria and Firmicutes among diabetics and non-diabetics. Veillonella, Prevotella, Porphyromonas, Leptotrichia, Lactobacillus, and Streptococcus were greater in diabetics whereas the abundance of Capnocytophaga and Neisseria was more among non-diabetics (p < 0.05).

Conclusions

The genera Veillonella, Prevotella, Porphyromonas, Leptotrichia, Lactobacillus, and Streptococcus were comparatively over the odds with the diabetics in India. The association between microbiota in diabetic population and risk related to increase in occurrence of caries, gingivitis, and periodontitis in diabetic population prevalence should be investigated.

Pericardial Effusion in Association With Periodontitis: Case Report and Review of 8 Patients in Literature

Periodontal diseases are well-known background for infective endocarditis. Here, we show that pericardial effusion or pericarditis might have origin also in periodontal diseases. An 86-year-old man with well-controlled hypertension and diabetes mellitus developed asymptomatic increase in pericardial effusion. Two weeks previously, he took oral new quinolone antibiotics for a week because he had painful periodontitis along a dental bridge in the mandibular teeth on the right side and presented cheek swelling. The sputum was positive for Streptococcus species. He was healthy and had a small volume of pericardial effusion for the previous 5 years after drug-eluting coronary stents were inserted at the left anterior descending branch 10 years previously. The differential diagnoses listed for pericardial effusion were infection including tuberculosis, autoimmune diseases, and metastatic malignancy. Thoracic to pelvic computed tomographic scan demonstrated no mass lesions, except for pericardial effusion and a small volume of pleural effusion on the left side. Fluorodeoxyglucose positron emission tomography disclosed many spotty uptakes in the pericardial effusion. The patient denied pericardiocentesis, based on his evaluation of the risk of the procedure. He was thus discharged in several days and followed at outpatient clinic. He underwent dental treatment and pericardial effusion resolved completely in a month. He was healthy in 6 years until the last follow-up at the age of 92 years. We also reviewed 8 patients with pericarditis in association with periodontal diseases in the literature to reveal that periodontal diseases would be the background for developing infective pericarditis and also mediastinitis on some occasions.

Resveratrol attenuates advanced glycation end product-induced senescence and inflammation in human gingival fibroblasts

Background/purpose

The accumulation of advanced glycation end products (AGEs) lead to a series of immune responses such as: increased oxidative stress and inflammation which contribute to the development of diabetic complications and periodontal disease. Resveratrol is a natural compound that has anti-oxidant and anti-inflammatory effects. Studies have found that diabetes-induced periodontitis is mainly caused by oxidative stress, aging and increased inflammation. In view of resveratrol has been proposed to have the ability in anti-oxidant and anti-inflammation in a variety of tissues. However, the role of resveratrol in diabetic periodontitis remains to be investigated. In this study, we aimed to investigate the role of resveratrol in preventing and treating diabetic periodontitis.

Materials and methods

First, cell proliferation was measured in AGEs-treated human gingival fibroblast with or without resveratrol. We examined the reactive oxygen species (ROS) generation, senescence-associated beta-galactosidase (SA-β-gal) and senescence marker p16 in human gingival fibroblasts (HGFs) stimulated with AGEs with or without the treatment of resveratrol. To determine whether resveratrol has the potential to regulate inflammaging which is mediated via the NF-κB signaling pathway and, the expression of p65 and p-IκB were also investigated. Furthermore, the concentration of interleukin (IL)-6 and IL-8 were also measured in AGEs-stimulated HGFs treated with or without resveratrol.

Results

ROS generation, cell senescence, and the secretion of IL-6 and IL-8 were significantly upregulated following the treatment of AGEs. However, the administration of resveratrol suppresses the generation of IL-6 and IL-8 and cell senescence via inhibiting NF-κB signaling pathway. Our results revealed that resveratrol inhibits inflammaging by downregulating NF-κB signaling pathway.

Conclusion

According to our findings, AGEs increase senescence and the production of proinflammatory cytokines in the gingiva, while the administration of resveratrol impedes inflammaging via suppressing NF-κB signaling pathway.

Current concepts in the pathogenesis of periodontitis: from symbiosis to dysbiosis

The primary etiological agent for the initiation and progression of periodontal disease is the dental plaque biofilm which is an organized aggregation of microorganisms residing within a complex intercellular matrix. The non-specific plaque hypothesis was the first attempt to explain the role of the dental biofilm in the pathogenesis of periodontal diseases. However, the introduction of sophisticated diagnostic and laboratory assays has led to the realisation that the development of periodontitis requires more than a mere increase in the biomass of dental plaque. Indeed, multispecies biofilms exhibit complex interactions between the bacteria and the host. In addition, not all resident microorganisms within the biofilm are pathogenic, since beneficial bacteria exist that serve to maintain a symbiotic relationship between the plaque microbiome and the host’s immune-inflammatory response, preventing the emergence of pathogenic microorganisms and the development of dysbiosis. This review aims to highlight the development and structure of the dental plaque biofilm and to explore current literature on the transition from a healthy (symbiotic) to a diseased (dysbiotic) biofilm in periodontitis and the associated immune-inflammatory responses that drive periodontal tissue destruction and form mechanistic pathways that impact other systemic non-communicable diseases.

Association between periodontal disease and hypertriglyceridemia: Propensity score matching analysis using the 7th Korea National Health and Nutrition Examination Survey

The prevalence of periodontitis and dyslipidemia continues to increase, and several studies have reported an association between the 2. Therefore, we assessed the relationship between periodontitis and hypertriglyceridemia using propensity score matching to efficiently address confounding factors, as well as complex sample analysis with data from Korea National Health and Nutrition Examination Survey VII (2016-2018). To match the 1:1 ratio between the groups with and without periodontitis, the propensity scores of covariates, such as age, sex, education, income, smoking, drinking, obesity, and diabetes mellitus, were calculated using logistic regression. Both results of logistic regression analysis using complex sample design for whole and matched sample after propensity score matching demonstrated a significant association between hypertriglyceridemia and periodontitis, of which the adjusted odds ratio was 1.28 (95% confidence interval = 1.10-1.50) and 1.29 (95% confidence interval = 1.09-1.52), respectively. Our findings suggest that dental healthcare workers can help raise awareness among patients with periodontitis regarding the association between periodontitis and hypertriglyceridemia, which may help them manage the condition and receive treatment.

Induction of Collagenolytic MMP-8 and -9 Tissue Destruction Cascade in Mouth by Head and Neck Cancer Radiotherapy: A Cohort Study

The effect of head and neck cancer (HNC) radiotherapy (RT) on biomarkers is not known but there is a lot of potential for gaining more precise cancer treatments and less side effects. This cohort study investigated the levels and molecular forms of the matrix metalloproteinase (MMP) -8 and -9, tissue inhibitor of metalloproteinase (TIMP)-1, myeloperoxidase (MPO) and interleukin (IL)-6 in mouth-rinse samples as well as the clinical periodontal status in HNC patients (n = 21) receiving RT. Complete periodontal examinations were performed pre-RT and one month after RT. Mouth-rinse samples (pre-RT, after six weeks of RT and one month after RT) were assayed using a point-of-care-kit (PerioSafe®/ORALyzer® (Dentognostics GmbH, Jena, Germany)) for active MMP-8 and ELISA analysis for total MMP-8 and -9, MPO, TIMP-1, and IL-6 levels. Molecular forms of MMP-9 were assessed by gelatinolytic zymography and MMP-8 by western immunoblot. Significant changes were observed between the three time points in the mean levels of active and total MMP-8, active MMP-9, and IL-6. Their levels increased during the RT and decreased after the RT period. The aMMP-8 levels stayed elevated even one month after RT compared to the pre-RT. Clinical attachment loss, probing depths, and bleeding on probing were increased between pre- and post-calculations in periodontal status. Elevated inflammatory biomarker levels together with clinical recordings strongly suggest that RT eventually increases the risk to the periodontal tissue destruction by inducing the active proteolytical MMP-cascade, and especially by prolonged activity of collagenolytic aMMP-8. Eventually, the aMMP-8 point-of-care mouth-rinse test could be an easy, early detection tool for estimating the risk for periodontal damage by the destructive MMP-cascade in HNC patients with RT treatment.

Luteolin inhibits Porphyromonas gingivalis growth and alleviates alveolar bone destruction in experimental murine periodontitis

Periodontal disease is a major oral infectious disease that destroys alveolar bones and causes tooth loss. Porphyromonas gingivalis is a key pathogen that plays a crucial role in periodontitis. In our previous study on the anti-P. gingivalis activity of flavonoid, luteolin, a major flavonoid in edible plants, inhibited the proteolytic activity of gingipains, the major virulence factor in P. gingivalis. This study demonstrated luteolin in vitro and in vivo anti-bacterial activities. Thus, luteolin inhibits planktonic growth and biofilm formation in P. gingivalis. Furthermore, oral administration of luteolin alleviated maxillary alveolar bone resorption (ABR) in murine periodontitis induced by P. gingivalis infection. These results indicate that luteolin may be a potential therapeutic compound that targets P. gingivalis by hindering its growth, biofilm formation, and ABR in the oral cavity.

Persistent enrichment of multidrug resistant Klebsiella in oral and nasal communities during long-term starvation

The human oral and nasal cavities can act as reservoirs for opportunistic pathogens capable of causing acute infection. These microbes asymptomatically colonize the human oral and nasal cavities which facilitates transmission within human populations via the environment, and they routinely possess a clinically-significant antibiotic-resistance genes. Among these opportunistic pathogens, the Klebsiella genus stands out as a notable example, with its members frequently linked to nosocomial infections and multidrug resistance. As with many colonizing opportunistic pathogens, how Klebsiella transitions from an asymptomatic colonizer to a pathogen remains unclear. Here, we explored a possible explanation by investigating the ability of oral and nasal Klebsiella to outcompete their native microbial community members under in vitro starvation conditions, which could be analogous to external hospital environments. When Klebsiella was present within a healthy human oral or nasal sample, the bacterial community composition shifted dramatically under starvation conditions and typically became dominated by Klebsiella. Furthermore, introducing K. pneumoniae exogenously into a native microbial community lacking K. pneumoniae, even at low inoculum, led to repeated dominance under starvation. K.pneumoniae strains isolated from healthy individuals' oral and nasal cavities also exhibited resistance to multiple classes of antibiotics and were genetically similar to clinical and gut isolates. In addition, we found that in the absence of Klebsiella, other understudied opportunistic pathogens, such as Peptostreptococcus, dominate under starvation conditions. Our findings establish an environmental circumstance that allows for the outgrowth of Klebsiella and other opportunistic pathogens. The ability to outcompete other commensal bacteria and to persist under harsh environmental conditions may contribute to the colonization-to-infection transition of these opportunistic pathogens.

An exploratory study of children with caries and its relationship to SARS-CoV-2

This exploratory study investigated whether children with dental decay were more likely to have COVID-19 than those without caries. The children underwent dental inspection and blood collection for detection of SARS-CoV-2 antibodies. Fifty-four children aged 6 to 9 years participated in the survey, which was conducted between March and June 2020 in the municipality of Ipojuca, Pernambuco, Brazil. The diagnosis of caries was performed using the dmft and DMFT indices. Parents reported signs and symptoms of sickness in their children during this period. The serology test aimed to verify the immune response of the children to coronavirus by detecting IgM/IgG antibodies. Statistical analyses were performed at P < 0.05. The majority of the children presented caries (68.5%). Of the nine children who tested positive for COVID-19 (16.7%), eight presented IgG antibodies to the virus, and only one had IgG and IgM antibodies to SARS-CoV2. Children who tested positive for SARS-CoV-2 had a higher percentage of caries lesions than those who tested negative for SARS-CoV-2 (77.8% vs 65.9%), but this difference was not statistically significant.