Increased infection with key periodontal pathogens during gestational diabetes mellitus

Salivary microbiome in kidney diseases: A narrative review

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

The Association between Gestational Diabetes Mellitus and Infections in Pregnancy-Systematic Review and Meta-Analysis

We conducted a systematic review and meta-analysis to evaluate the association between gestational diabetes mellitus and infections during pregnancy. We included cross-sectional, case-control, cohort studies and clinical trials, evaluating the frequency of infections in women with and without gestational diabetes mellitus. A search was conducted in Embase, PubMed, and Web of Science electronic databases and by manually searching references, until 23 March 2022, resulting in 16 studies being selected for review, with 111,649 women in the gestational diabetes mellitus group, and 1,429,659 in the controls. Cochrane's Q test of heterogeneity and I² were used to assess heterogeneity. Pooled odds ratio (OR) was calculated. Funnel plots and Egger test were used for assessment of publication bias. The results showed a significant association between gestational diabetes mellitus and infections (pooled-OR 1.3 95% CI [1.2-1.5]). Sub-analyses showed a significant association for urinary tract infections (pooled-OR of 1.2 95% CI [1.1-1.3]), bacterial infections (pooled-OR were 1.2 95% CI [1.1-1.4]), and SARS-CoV-2 (pooled-OR 1.5 95% CI [1.2-2.0]) but not to gingivitis or vaginal candidiasis. The results underscore the significance of acknowledging gestational diabetes mellitus as a risk factor for infections.

Saliva as Biomarker for Oral and Chronic Degenerative Non-Communicable Diseases

Saliva is a very complex fluid and it is essential to maintain several physiological processes and functions, including oral health, taste, digestion and immunological defenses. Saliva composition and the oral microbiome can be influenced by several factors, like diet and smoking habits, and their alteration can represent an important access point for pathogens and, thus, for systemic illness onset. In this review, we explore the potentiality of saliva as a new tool for the early detection of some pathological conditions, such as oral diseases, chronic degenerative non-communicable diseases, among these chronic kidney disease (CKD). We also examined the possible correlation between oral and systemic diseases and oral and gut microbiota dysbiosis. In particular, we deeply analyzed the relationship between oral diseases and CKD. In this context, some salivary parameters can represent a new device to detect either oral or systemic pathologies. Moreover, the positive modulation of oral and gut microbiota induced by prebiotics, postbiotics, or symbiotics could represent a new possible adjuvant therapy in the clinical management of oral diseases and CKD.

Comparison of oxidative stress markers in the saliva, gingival crevicular fluid, and serum samples of pregnant women with gestational diabetes and healthy pregnant women

BACKGROUND AND OBJECTIVE

To compare oxidative stress (OS) markers in the saliva, gingival crevicular fluid (GCF), and serum samples of pregnant women with gestational diabetes (GDM) and healthy pregnant women and to investigate the association between periodontal health/diseases and OS and GDM.

METHOD

Eighty women with GDM and 80 healthy pregnant women were included in the study. Medical and clinical anamnesis was obtained from all the pregnant women included in the study, and their plaque index (PI), gingival index (GI), bleeding on probing (BoP), probing pocket depth (PPD), and clinical attachment level (CAL) measurements were performed. GCF, saliva, and serum samples were collected for the measurements of the local and systemic total antioxidant status (TAS) and total oxidant status (TOS).

RESULTS

Clinical periodontal parameters were found to be significantly higher in the GDM group compared to the control group. The serum and saliva TAS, TOS, and TAS/TOS values were significantly lower in the GDM group than in the control group. In the analysis of the GCF samples, the mean TAS and TAS/TOS values were significantly lower and the TOS value was significantly higher in the GDM group than in the control group. The multivariate reduced model indicated that gravidity, salivary TAS/TOS, and GCF TAS were significant independent variables in the development of GDM (p < .05).

CONCLUSION

Our results indicated that the OS of serum, saliva, and GCF samples increased in patients with GDM compared to healthy pregnant women. The role of local OS parameters in GDM may be associated with elevated clinical periodontal parameters.

Periodontal disease severity is associated to pathogenic consortia comprising putative and candidate periodontal pathogens

BACKGROUND

Based on a holistic concept of polymicrobial etiology, we have hypothesized that putative and candidate periodontal pathogens are more frequently detected in consortia than alone in advanced forms of periodontal diseases (PD).

OBJECTIVE

To correlate specific consortia of periodontal pathogens with clinical periodontal status and severity of periodontitis.

METHODOLOGY

Subgingival biofilm was obtained from individuals with periodontal health (113, PH), gingivitis (91, G), and periodontitis (209, P). Genomic DNA was purified and the species Aggregatibacter actinomycetemcomitans (Aa), Aa JP2-like strain, Porphyromonas gingivalis (Pg), Dialister pneumosintes (Dp), and Filifactor alocis (Fa) were detected by PCR. Configural frequency and logistic regression analyses were performed to correlate microbial consortia and PD.

RESULTS

Aa + Pg in the presence of Dp (phi=0.240; χ2=11.9, p<0.01), as well as Aa JP2 + Dp + Fa (phi=0.186, χ2=4.6, p<0.05) were significantly more associated in advanced stages of P. The consortium Aa + Fa + Dp was strongly associated with deep pocketing and inflammation (p<0.001). The best predictors of disease severity (80% accuracy) included older age (OR 1.11 [95% CI 1.07 - 1.15], p<0.001), Black/African-American ancestry (OR 1.89 [95% CI 1.19 - 2.99], p=0.007), and high frequency of Aa + Pg + Dp (OR 3.04 [95% CI 1.49 - 6.22], p=0.002).

CONCLUSION

Specific microbial consortia of putative and novel periodontal pathogens, associated with demographic parameters, correlate with severe periodontitis, supporting the multifactorial nature of PD.

Tobacco smoke exacerbates Filifactor alocis pathogenicity

AIM

Filifactor alocis has recently emerged as a periodontal pathobiont that appears to thrive in the oral cavity of smokers. We hypothesized that identification of smoke-responsive F. alocis genes would provide insight into adaptive strategies and that cigarette smoke would enhance F. alocis pathogenesis in vivo.

MATERIALS AND METHODS

F. alocis was grown in vitro and cigarette smoke extract-responsive genes determined by RNAseq. Mice were exposed, or not, to mainstream 1R6F research cigarette smoke and infected with F. alocis, or not, in an acute ligature model of periodontitis. Key clinical, infectious, and immune data were collected.

RESULTS

In culture, F. alocis growth was unaffected by smoke conditioning and only a small number of genes were specifically regulated by smoke exposure. Reduced murine mass, differences in F. alocis-cognizant antibody production, and altered immune profiles as well as altered alveolar bone loss were all attributable to smoke exposure and/or F. alocis infection in vivo.

CONCLUSIONS

F. alocis is well-adapted to tobacco-rich conditions and its pathogenesis is enhanced by tobacco smoke exposure. A smoke-exposed ligature model of periodontitis shows promise as a tool with which to further unravel mechanisms underlying tobacco-enhanced, bacteria-induced disease.

Association of general health and lifestyle factors with the salivary microbiota - Lessons learned from the ADDITION-PRO cohort

INTRODUCTION

Previous research indicates that the salivary microbiota may be a biomarker of oral as well as systemic disease. However, clarifying the potential bias from general health status and lifestyle-associated factors is a prerequisite of using the salivary microbiota for screening.

MATERIALS & METHODS

ADDDITION-PRO is a nationwide Danish cohort, nested within the Danish arm of the Anglo-Danish-Dutch Study of Intensive treatment in People with Screen-Detected Diabetes in Primary Care. Saliva samples from n=746 individuals from the ADDITION-PRO cohort were characterized using 16s rRNA sequencing. Alpha- and beta diversity as well as relative abundance of genera was examined in relation to general health and lifestyle-associated variables. Permutational multivariate analysis of variance (PERMANOVA) was performed on individual variables and all variables together. Classification models were created using sparse partial-least squares discriminant analysis (sPLSDA) for variables that showed statistically significant differences based on PERMANOVA analysis (p < 0.05).

RESULTS

Glycemic status, hemoglobin-A_1c (HbA_1c) level, sex, smoking and weekly alcohol intake were found to be significantly associated with salivary microbial composition (individual variables PERMANOVA, p < 0.05). Collectively, these variables were associated with approximately 5.8% of the observed differences in the composition of the salivary microbiota. Smoking status was associated with 3.3% of observed difference, and smoking could be detected with good accuracy based on salivary microbial composition (AUC 0.95, correct classification rate 79.6%).

CONCLUSIONS

Glycemic status, HbA_1c level, sex, smoking and weekly alcohol intake were significantly associated with the composition of the salivary microbiota. Despite smoking only being associated with 3.3% of the difference in overall salivary microbial composition, it was possible to create a model for detection of smoking status with a high correct classification rate. However, the lack of information on the oral health status of participants serves as a limitation in the present study. Further studies in other cohorts are needed to validate the external validity of these findings.

Multi-omics analysis reveals the host-microbe interactions in aged rhesus macaques

Aging is a complex multifactorial process that greatly affects animal health. Multi-omics analysis is widely applied in evolutionary biology and biomedical research. However, whether multi-omics can provide sufficient information to reveal comprehensive changes in aged non-human primates remains unclear. Here, we explored changes in host-microbe interactions with aging in Chinese rhesus macaques (Macaca mulatta lasiota, CRs) using multi-omics analysis. Results showed marked changes in the oral and gut microbiomes between young and aged CRs, including significantly reduced probiotic abundance and increased pathogenic bacterial abundance in aged CRs. Notably, the abundance of Lactobacillus, which can metabolize tryptophan to produce aryl hydrocarbon receptor (AhR) ligands, was decreased in aged CRs. Consistently, metabolomics detected a decrease in the plasma levels of AhR ligands. In addition, free fatty acid, acyl carnitine, heparin, 2-(4-hydroxyphenyl) propionic acid, and docosahexaenoic acid ethyl ester levels were increased in aged CRs, which may contribute to abnormal fatty acid metabolism and cardiovascular disease. Transcriptome analysis identified changes in the expression of genes associated with tryptophan metabolism and inflammation. In conclusion, many potential links among different omics were found, suggesting that aged CRs face multiple metabolic problems, immunological disorders, and oral and gut diseases. We determined that tryptophan metabolism is critical for the physiological health of aged CRs. Our findings demonstrate the value of multi-omics analyses in revealing host-microbe interactions in non-human primates and suggest that similar approaches could be applied in evolutionary and ecological research of other species.

Salivary microbiome in chronic kidney disease: what is its connection to diabetes, hypertension, and immunity?

BACKGROUND

The association between oral dysbiosis and chronic kidney disease (CKD) has gained increasing attention in recent years. Diabetes and hypertension are the most common conditions in CKD. However, a case-control study with matched confounding variables on the salivary microbiome in CKD and the influence of diabetes and hypertension on the microbiome has never been reported.

METHODS

In our study, we compared the salivary microbiome profile between patients with CKD and healthy controls (HC) using 16S ribosomal DNA sequencing and examine its association with diabetes, hypertension, and immunity.

RESULTS

We observed that the bacterial community was skewed in the saliva of CKD, with increased Lautropia and Pseudomonas, and decreased Actinomyces, Prevotella, Prevotella 7, and Trichococcus. No difference in the bacterial community between the CKD patients complicated with and without diabetes, and between those with and without hypertension. Prevotella 7 declined in CKD patients with/without hypertension with respect to HC, while Pseudomonas increased in CKD patients with/without hypertension. Pseudomonas was negatively associated with immunoglobin G in CKD patients. Both CKD patients with positive and negative antistreptolysin O had declined Prevotella 7 and Trichococcus compared to HC, whereas increased Pseudomonas.

CONCLUSIONS

Our study identifies a distinct bacterial saliva microbiome in CKD patients characterized by alteration in composition. We unravel here that the co-occurrence diseases of diabetes and hypertension are not associated with specific bacterial alterations, suggesting that bacterial dysbiosis in saliva plays a role in renal damage regardless of the occurrence of diabetes and hypertension.

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.

Association between gestational diabetes mellitus and periodontitis via the effect of reactive oxygen species in peripheral blood cells

BACKGROUND

Periodontitis (P) has emerged as a risk factor for gestational diabetes mellitus (GDM) through immune cell function alterations, elevated proinflammatory mediators, and increased reactive oxygen species (ROS). The main objective of present study was to determine associations between pregnancy with and without GDM and P. The secondary objective was to compare ROS production in peripheral blood cells (PBCs) of pregnant women with and without GDM.

METHODS

This cross-sectional case-control study included 128 pregnant women: 64 with and 64 without GDM. All participants were examined for clinical parameters of GDM and periodontal conditions. Associations between GDM-related periodontal data and GDM risk were evaluated by multiple logistic regression. PBCs were isolated and cultured. ROS productions in each PBCs types was investigated by flow cytometry with ROS antibodies.

RESULTS

P was significantly more prevalent in pregnant women with GDM than in those without GDM (57.8% versus 37.5%), with an odds ratio (OR) of 2.28, and a 95% confidence interval (CI) of 1.12 to 4.64 (P = 0.022). The OR (95% CI) was 2.59 (1.19 to 5.65) (P = 0.017) after adjusting for potential confounding factors, including diabetes mellitus (DM) family history, age ≥30 years, body mass index, and maternal age. ROS levels in all PBCs types were significantly higher in the GDM than in the non-GDM group (P < 0.05).

CONCLUSION

This study supported the association between P and GDM and indicated that P may be a risk factor for GDM. High levels of ROS production in the PBCs of pregnant women with GDM emphasized the association with GDM.

The Microbiome in Periodontitis and Diabetes

Objectives

To perform a comprehensive and integrative review of the available literature on the potential changes in the microbiome of healthy and individuals with diabetes under periodontal health and disease.

Materials and Methods

The review was conducted by two independent reviewers. Indexed electronic databases (PubMed/Medline, Cochrane Library, Web of Science and Scopus) were searched, including articles published in English and dated from 5 years ago until December 2021. A manual search also was performed to identify co-related articles. Following the removal of duplicates and eligibility criteria, the articles were included in tables for analysis and described in the manuscript.

Results

According to this review, diabetes mellitus was associated with significant changes in the subgingival and salivary microbiome, either in its association with periodontitis or in cases of periodontal health. In addition to affecting microbial diversity in terms of taxonomy, metagenomic studies have shown that this endocrine disorder may also be directly related to increased pathogenicity in the oral microbiome.

Conclusion

Although the reviewed studies demonstrate important differences in the subgingival and salivary microbiome composition because of diabetes mellitus, further studies are needed to clarify the real effects of hyperglycemia on oral microbial profiles and support new diagnostic approaches and innovative treatments.

Development of gestational diabetes mellitus in women with periodontitis in early pregnancy: A population-based clinical study

AIM

This study aimed to determine whether periodontitis in early pregnancy and periodontal therapy during gestation affect the incidence of gestational diabetes mellitus (GDM) through a population-based clinical study.

MATERIALS AND METHODS

Subjects without periodontitis at 1-4 weeks of gestation who met our inclusion criteria were enrolled in the non-periodontitis group. Periodontitis patients who agreed or refused to receive periodontal therapy during pregnancy were separately enrolled in the periodontitis treated or untreated group. At 12-16 weeks of gestation, gingival crevicular fluid (GCF) and venous blood were collected for analyses of bacterial species and serum inflammatory mediators, respectively. At 24-28 weeks of gestation, GDM patients were identified by oral glucose tolerance tests. The association tests were performed using Chi-squared statistics and regression analyses.

RESULTS

The complete data of 3523 pregnant women were recorded during the study period. GDM incidence among the untreated periodontitis participants (84/749, 11.21%) was significantly higher than that among the non-periodontitis participants (108/2255, 4.79%) (p < .05), and periodontal treatment during gestation reduced the incidence from 11.21% (untreated group) to 7.32% (38/519, treated group) (p < .05). Based on multiple logistic regression analyses, it was found that periodontitis in early pregnancy was associated with GDM, and three-step regression analyses showed that Porphyromonas gingivalis (P. gingivalis) and the serum TNF-α and IL-8 levels played a role in the association between untreated periodontitis and GDM. Furthermore, Pearson's correlation test indicated that the existence of P. gingivalis in GCF was positively correlated with high serum levels of these two inflammatory mediators.

CONCLUSIONS

This study establishes a connection between periodontitis in early pregnancy and GDM and demonstrates that the presence of P. gingivalis is associated with high levels of inflammatory mediators in serum, and thereby may contribute to the development of GDM. In-depth mechanistic studies are needed to further support these findings.

Maternal Periodontal Disease: A Possible Risk Factor for Adverse Pregnancy Outcomes in the Qassim Region of Saudi Arabia

BACKGROUND AND AIMS

In periodontal disease, pathogenic inflammatory factors hold a vital part in adverse pregnancy outcomes. In recent years, there has been a large amount of literature concerning the association between periodontal disease and adverse pregnancy outcomes such as preterm birth (PTB) and low-birth-weight baby (LBWB). In the Middle-east region, reports indicate a higher rate of adverse pregnancy outcomes, and periodontitis is believed to be one of several risk factors for adverse pregnancy outcomes. This cross-sectional, epidemiological study aimed to investigate the prevalence of periodontal diseases among pregnant women in the Qassim region and its association as a possible risk factor for adverse pregnancy outcomes.

MATERIALS AND METHODOLOGY

This was a cross-sectional, epidemiological study of 380 pregnant women from the 8^th week postconception to parturition who were attending to Maternal and Children's Hospital in Buraidah, Qassim, KSA. The data were collected through questionnaire and oral examination. Plaque scores (Silness and Loe) and gingival disease scores (Ramfjord Periodontal Disease Index [PDI]) were used to assess oral hygiene status. The questionnaire data collected included gestational age, plaque control habits, previous incidences of premature birth, and awareness of expectant mothers about periodontal disease.

RESULTS

Data were collected for 380 participants. Our results based on the plaque index and PDI showed that all (100%) of these 380 pregnant women suffered periodontal diseases (gingivitis 78.9% and periodontitis 21.1%). The distribution of gingivitis was the highest among 3^rd trimester patients and lowest among 1^st trimester patients. Mild-to-moderate types of periodontitis (4 mm-5 mm) were more prevalent among the participants compared with severe (more than 6 mm) forms of periodontitis with a higher prevalence in the 3^rd trimester (7-9 months) of gestational age.

CONCLUSIONS

A very strong significant association of pregnancy and periodontal disease in the Saudi population (Qassim Region) and periodontal disease is risk factor for PTB and LBWB for these patients.

Filifactor alocis: Recent Insights and Advances

Filifactor alocis, a fastidious Gram-positive obligate anaerobic bacterium, is a newly appreciated member of the periodontal community that is now proposed to be a diagnostic indicator of periodontal disease. Its pathogenic characteristics are highlighted by its ability to survive in the oxidative stress-rich environment of the periodontal pocket and to significantly alter the microbial community dynamics by forming biofilms and interacting with several oral bacteria. Here, we describe the current understanding of F. alocis virulence attributes, such as its comparative resistance to oxidative stress, production of unique proteases and collagenases that can cause structural damage to host cells, and dysregulation of the immune system, which enable this bacterium to colonize, survive, and outcompete other traditional pathogens in the inflammatory environment of the periodontal pocket. Furthermore, we explore the recent advancements and future directions for F. alocis research, including the potential mechanisms for oxidative stress resistance and our evolving understanding of the interactions and mechanisms of bacterial survival inside neutrophils. We also discuss the current genetic tools and challenges involved in manipulating the F. alocis genome for the functional characterization of the putative virulence genes. Collectively, this information will expedite F. alocis research and should lead to the identification of prime targets for the development of novel therapeutics to aid in the control and prevention of periodontal disease.

Porphyromonas gingivalis fimbrial protein Mfa5 contains a von Willebrand factor domain and an intramolecular isopeptide

The Gram-negative bacterium Porphyromonas gingivalis is a secondary colonizer of the oral biofilm and is involved in the onset and progression of periodontitis. Its fimbriae, of type-V, are important for attachment to other microorganisms in the biofilm and for adhesion to host cells. The fimbriae are assembled from five proteins encoded by the mfa1 operon, of which Mfa5 is one of the ancillary tip proteins. Here we report the X-ray structure of the N-terminal half of Mfa5, which reveals a von Willebrand factor domain and two IgG-like domains. One of the IgG-like domains is stabilized by an intramolecular isopeptide bond, which is the first such bond observed in a Gram-negative bacterium. These features make Mfa5 structurally more related to streptococcal adhesins than to the other P. gingivalis Mfa proteins. The structure reported here indicates that horizontal gene transfer has occurred among the bacteria within the oral biofilm.

Sociodemographic Differences in Health Awareness and Oral Health in Pregnant Women

Objective The aim of this study was to determine the present oral health status of pregnant women depending on selected sociodemographic differences and deduce any resulting consequences for health prevention.

Methods The participantsʼ data of relevance to the study such as age, school leaving qualification, migration background, smoking habits or last dentist visit were recorded using a questionnaire. The subsequent dental check-up concentrated on open carious lesions, any initiated root canal treatments and missing teeth. Finally, the Periodontal Screening Index was recorded to diagnose the presence of any gingivitis or periodontitis. The subsequent biometric evaluation comprised descriptive data analysis, χ2 test and logistical regression.

Results The higher the school leaving qualification, the lower the probability that a pregnant woman smoked prior to pregnancy (OR 0.291; 95% CI 0.114 – 0.743) and that tartar was diagnosed (OR 0.424; 95% CI 0.185 – 0.973). Regular dentist visits (OR 4.026; 95% CI 1.613 – 10.049) increase with the attained school leaving qualification. There is a greater chance that women born in Germany taking part in the study were aware of dental risks in pregnancy (OR 2.652; 95% CI 1.285 – 5.472) and attended the dentist during pregnancy (OR 2.507; 95% CI 1.281 – 4.907).

Conclusion The rate of awareness of the risks and consequences of pregnancy for oral health must be increased. The main aim for primary prophylaxis should be a reduction in the periodontal bacteria and caries of the mother and father.

Periodontal disease and adverse pregnancy outcomes

Periodontal diseases are considered not only to affect tooth-supporting tissues but also to have a cause-and-effect relationship with various systemic diseases and conditions, such as adverse pregnancy outcomes. Mechanistic studies provide strong evidence that periodontal pathogens can translocate from infected periodontium to the feto-placental unit and initiate a metastatic infection. However, the extent and mechanisms by which metastatic inflammation and injury contribute to adverse pregnancy outcomes still remain unclear. The presence of oral bacteria in the placenta of women with term gestation further complicates our understanding of the biology behind the role of periodontal pathogens in pregnancy outcomes. Epidemiological studies demonstrate many methodological inconsistencies and flaws that render comparisons difficult and conclusions insecure. Therefore, despite the fact that a number of prospective studies show a positive association between periodontal diseases and various adverse pregnancy outcomes, the evidence behind it is still weak. Future well-designed explanatory studies are necessary to verify this relationship and, if present, determine its magnitude. The majority of high-quality randomized controlled trials reveal that nonsurgical periodontal therapy during the second trimester of gestation does not improve pregnancy outcomes. From a biological standpoint, this can be partially explained by the fact that therapy rendered at the fourth to sixth months of pregnancy is too late to prevent placental colonization by periodontal pathogens and consequently incapable of affecting pathogen-induced injury at the feto-placental unit. Thus, interventions during the preconception period may be more meaningful. With the increase in our understanding on the potential association between periodontal disease and adverse pregnancy outcomes, it is clear that dental practitioners should provide periodontal treatment to pregnant women that is safe for both the mother and the unborn child. Although there is not enough evidence that the anti-infective therapy alters pregnancy outcomes, it improves health-promoting behavior and periodontal condition, which in turn advance general health and risk factor control.

The salivary microbiota in health and disease

The salivary microbiota (SM), comprising bacteria shed from oral surfaces, has been shown to be individualized, temporally stable and influenced by diet and lifestyle. SM reflects local bacterial alterations of the supragingival and subgingival microbiota, and periodontitis and dental-caries associated characteristics of SM have been reported. Also, data suggest an impact of systemic diseases on SM as demonstrated in patients with a wide variety of systemic diseases including diabetes, cancer, HIV and rheumatoid arthritis. The presence of systemic diseases seems to influence salivary levels of specific bacterial species, as well as α- and β-diversity of SM. The composition of SM might thereby potentially mirror oral and general health status. The contentious development of advanced molecular techniques such as metagenomics, metatranscriptomics and metabolomics has enabled the possibility to address bacterial functions rather than presence in microbial samples. However, at present only a few studies have employed such techniques on SM to reveal functional and metabolic characteristics in oral health and disease. Future studies are therefore warranted to illuminate the possible impact of metabolic functions of SM on oral and general health status. Ultimately, such an approach has the possibility to reveal novel and personalized therapeutic avenues in oral and general medicine.

Quantitative analysis of key periodontopathic bacteria in gestational diabetic and non-diabetic women

PURPOSE

The aim of this study is to compare the periodontal status and quantify Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi) from plaque samples of both gestational diabetic mellitus (GDM) and non diabetic pregnant women.

MATERIALS AND METHODS

Sixty first time pregnant women were selected after adjusting for age, duration of pregnancy and educational status. They were then categorized into gestational diabetic women (GDM) (Group A) and healthy pregnant women (non GDM) (Group B). Periodontal examination was done by assessing gingival index, periodontal disease index and probing depth. Microbial analysis on sub-gingival plaque was performed using polymerase chain reaction (PCR). Statistical analysis was done by student t test, chi square test and Fischer exact test.

RESULTS

Group A showed higher gingival index, probing depth and periodontal disease index scores than group B at p < 0.001. Pg was detected in 80% of group A and 40% of group B. Amongst these; it was measured over 2.0 × 104 in 33% of group A, while in the group B it never scored more than 1.0 × 104. While Pi were also detected in 73% of group A women and 40% Group B women but quantification showed Pi > 2.0 × 104 in more number of group A women.

CONCLUSION

This study showed that there is significant association between the severity of periodontal disease and increased levels of Pg and Pi in gestational diabetic women.

Anti-Diabetic, Anti-Inflammatory, and Anti-Oxidant Effects of Naringenin in an In Vitro Human Model and an In Vivo Murine Model of Gestational Diabetes Mellitus

SCOPE

Gestational diabetes mellitus (GDM), which affects up to 20% of pregnant women, is associated with maternal peripheral insulin resistance, low-grade inflammation, and oxidative stress. The flavonoid naringenin has potent anti-diabetic, anti-inflammatory, and anti-oxidative properties; however, its effects in GDM remain unknown. The study aimed to determine the effects of naringenin on glucose metabolism, inflammation, and oxidative stress associated with GDM both in vitro and in vivo.

METHODS AND RESULTS

In vitro, human tissue samples obtained at term elective Caesarean section are stimulated with tumour necrosis factor alpha (TNF) to develop a GDM-like environment. Naringenin treatment significantly improves TNF-impaired glucose uptake in skeletal muscle. In placenta and visceral adipose tissue (VAT), naringenin significantly reduces expression of pro-inflammatory cytokines and chemokines and increases antioxidant mRNA expression. Mechanistically, naringenin suppresses nuclear factor κB activation. In vivo, pregnant heterozygous db/+ mice are used to model GDM. Daily intraperitoneal injections of GDM mice with naringenin from gestational day 10-17 significantly improve glucose tolerance, reduces IL1A mRNA expression, and increases antioxidant mRNA expression in placenta, VAT, and subcutaneous adipose tissue.

CONCLUSION

Naringenin is shown to improve insulin sensitivity, inflammation, and oxidative stress associated with GDM and shows promise as a novel preventive therapeutic.

Whole metagenomic shotgun sequencing of the subgingival microbiome of diabetics and non-diabetics with different periodontal conditions

OBJECTIVE

The aim of this study was to use high-resolution whole metagenomic shotgun sequencing to characterize the subgingival microbiome of patients with/without type 2 Diabetes Mellitus and with/without periodontitis.

DESIGN

Twelve subjects, falling into one of the four study groups based on the presence/absence of poorly controlled type 2 Diabetes Mellitus and moderate-severe periodontitis, were selected. For each eligible subject, subgingival plaque samples were collected at 4 sites, all representative of the periodontal condition of the individual (i.e., non-bleeding sulci in subjects without a history of periodontitis, bleeding pockets in patients with moderate-severe periodontitis). The subgingival microbiome was evaluated using high-resolution whole metagenomic shotgun sequencing.

RESULTS

The results showed that: (i) the presence of type 2 Diabetes Mellitus and/or periodontitis were associated with a tendency of the subgingival microbiome to decrease in richness and diversity; (ii) the presence of type 2 Diabetes Mellitus was not associated with significant differences in the relative abundance of one or more species in patients either with or without periodontitis; (iii) the presence of periodontitis was associated with a significantly higher relative abundance of Anaerolineaceae bacterium oral taxon 439 in type 2 Diabetes Mellitus patients.

CONCLUSIONS

Whole metagenomic shotgun sequencing of the subgingival microbiome was extremely effective in the detection of low-abundant taxon. Our results point out a significantly higher relative abundance of Anaerolineaceae bacterium oral taxon 439 in patients with moderate to severe periodontitis vs patients without history of periodontitis, which was maintained when the comparison was restricted to type 2 diabetics.

Peptide-Based Inhibitors of Fimbrial Biogenesis in Porphyromonas gingivalis

Periodontitis is a progressive inflammatory disease that affects roughly half of American adults. Colonization of the oral cavity by the Gram-negative bacterial pathogen Porphyromonas gingivalis is a key event in the initiation and development of periodontal disease. Adhesive surface structures termed fimbriae (pili) mediate interactions of P. gingivalis with other bacteria and with host cells throughout the course of disease. The P. gingivalis fimbriae are assembled via a novel mechanism that involves proteolytic processing of lipidated precursor subunits and their subsequent polymerization on the bacterial surface. Given their extracellular assembly mechanism and central roles in pathogenesis, the P. gingivalis fimbriae are attractive targets for anti-infective therapeutics to prevent or treat periodontal disease. Here we confirm that conserved sequences in the N and C termini of the Mfa1 fimbrial subunit protein perform critical roles in subunit polymerization. We show that treatment of P. gingivalis with peptides corresponding to the conserved C-terminal region inhibits the extracellular assembly of Mfa fimbriae on the bacterial surface. We also show that peptide treatment interferes with the function of Mfa fimbriae by reducing P. gingivalis adhesion to Streptococcus gordonii in a dual-species biofilm model. Finally, we show that treatment of bacteria with similar peptides inhibits extracellular polymerization of the Fim fimbriae, which are also expressed by P. gingivalis These results support a donor strand-based assembly mechanism for the P. gingivalis fimbriae and demonstrate the feasibility of using extracellular peptides to disrupt the biogenesis and function of these critical periodontal disease virulence factors.

Regulation of Vaginal Microbiome by Nitric Oxide

In this review, the composition and regulation of vaginal microbiome that displays an apparent microbial diversity and interacts with other microbiota in the body are presented. The role of nitric oxide (NO) in the regulation of vaginal microflora in which lactobacillus species typically dominate has been delineated from the perspective of maintaining gynecologic ecosystem and prevention of onset of bacteriostatic vaginosis (BV) and/or sexually transmitted diseases (STD) including HIV-1 transmission. The interactions between NO and vaginal microbiome and its influence on the levels of Lactobacillus, hormones and other components are described. The recent progress, such as NO drugs, probiotic Lactobacilli and Lactobacillus microbots, that can be explored to alleviate abnormality of vagina microbiome, is also discussed. An identification of Oral-GI-Vagina axis, as well as the relationship between NO and Lactobacillus regulation in the healthy or pathological status of vagina microbiome, surely offers the advanced drug delivery option against BV or STD including AIDS.

The oral microbiome and adverse pregnancy outcomes

Significant evidence supports an association between periodontal pathogenic bacteria and preterm birth and preeclampsia. The virulence properties assigned to specific oral pathogenic bacteria, for example, Fusobacterium nucleatum, Porphyromonas gingivalis, Filifactor alocis, Campylobacter rectus, and others, render them as potential collaborators in adverse outcomes of pregnancy. Several pathways have been suggested for this association: 1) hematogenous spread (bacteremia) of periodontal pathogens; 2) hematogenous spread of multiple mediators of inflammation that are generated by the host and/or fetal immune response to pathogenic bacteria; and 3) the possibility of oral microbial pathogen transmission, with subsequent colonization, in the vaginal microbiome resulting from sexual practices. As periodontal disease is, for the most part, preventable, the medical and dental public health communities can address intervention strategies to control oral inflammatory disease, lessen the systemic inflammatory burden, and ultimately reduce the potential for adverse pregnancy outcomes. This article reviews the oral, vaginal, and placental microbiomes, considers their potential impact on preterm labor, and the future research needed to confirm or refute this relationship.

Gene analysis of multiple oral bacteria by the polymerase chain reaction coupled with capillary polymer electrophoresis

Capillary polymer electrophoresis is identified as a promising technology for the analysis of DNA from bacteria, virus and cell samples. In this paper, we propose an innovative capillary polymer electrophoresis protocol for the quantification of polymerase chain reaction products. The internal standard method was modified and applied to capillary polymer electrophoresis. The precision of our modified internal standard protocol was evaluated by measuring the relative standard deviation of intermediate capillary polymer electrophoresis experiments. Results showed that the relative standard deviation was reduced from 12.4-15.1 to 0.6-2.3%. Linear regression tests were also implemented to validate our protocol. The modified internal standard method showed good linearity and robust properties. Finally, the ease of our method was illustrated by analyzing a real clinical oral sample using a one-run capillary polymer electrophoresis experiment.