Systemic immune responses in pregnancy and periodontitis: relationship to pregnancy outcomes in the Obstetrics and Periodontal Therapy (OPT) study

Periodontal disease in pregnancy and adverse pregnancy outcomes: Progress in related mechanisms and management strategies

Periodontal disease is an inflammatory and destructive disease of tissues supporting the tooth. A large number of studies have confirmed that periodontal pathogens and their metabolites can lead to adverse pregnancy outcomes in direct or indirect ways. Adverse pregnancy outcomes, such as preterm birth, low birth weight, and pre-eclampsia, have a serious impact on human reproductive health. In recent years, although the level of global medical technology has gradually improved, the incidence of adverse pregnancy outcomes has not declined and is still a global public health problem. The purpose of this review is to summarize the current data on periodontal disease in pregnancy and adverse pregnancy outcomes, including the association between periodontal disease and adverse pregnancy outcomes, the pathogenic mechanism related to this association, the efficacy of different nutrition supplements for both periodontal disease and adverse pregnancy outcomes and the effect of providing periodontal treatment on the occurrence of adverse pregnancy outcomes, to provide guidance for the prevention and treatment of adverse pregnancy outcomes in clinical practice.

Fusobacterium nucleatum - Friend or foe?

Fusobacterium nucleatum (F. nucleatum) is one of the most abundant Gram-negative anaerobic bacteria, part of the gut, and oral commensal flora, generally found in human dental plaque. Its presence could be associated with various human diseases, including, e.g., periodontal, angina, lung and gynecological abscesses. This bacteria can enter the blood circulation as a result of periodontal infection. It was proven that F. nucleatum migrates from its primary site of colonization in the oral cavity to other parts of the body. It could cause numerous diseases, including cancers. On the other hand, it was shown that Fusobacterium produces significant amounts of butyric acid, which is a great source of energy for colonocytes (anti-inflammatory cells). Therefore, it is very interesting to get to know the two faces of F. nucleatum.

Variations in IgG antibody subclass responses to oral bacteria: Effects of periodontal disease and modifying factors

BACKGROUND AND OBJECTIVE

Local and systemic IgG antibodies or oral bacteria have been described with periodontitis. We extended these observations by assessing the impact of a range of intrinsic factors on serum IgG subclass antibodies to both commensal and pathogenic oral bacteria that would contribute to variations in immune protection or disease susceptibility in periodontitis have not been described.

METHODS

Subjects (n = 278) were classified as healthy, gingivitis, or periodontitis and categorized as mild, moderate, and severe periodontitis. Demographic stratification included sex, age, race/ethnicity, smoking, and obesity. Whole formalin-fixed bacteria were used as antigens to detect serum immunoglobulin (Ig)G subclass antibody levels using an ELISA.

RESULTS

The greatest differences in variations in IgG subclasses occurred in periodontitis versus health or gingivitis to bacteria considered oral pathogens (eg, Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and Treponema denticola) with IgG1, IgG2, and IgG4 increased by three- to sevenfold with Pg. Differences in subclass levels and distribution were also observed related to disease severity, particularly related to individual subclass responses to Pg. Examination of the overall population showed that females had elevated antibody, reflected by elevated IgG2 amounts/proportions. The older group of subjects demonstrated elevated antibody to multiple oral bacteria, lacking any particular subclass pattern. IgG2 antibody to Aa and Pg was increased in smokers. Multiple IgG subclass antibody levels to oral pathogens were significantly decreased in the obese subset within this population.

CONCLUSION

This investigation identified patterns of IgG subclass antibody responses to oral bacteria and demonstrated substantial effects of disease impacting the level and subclass distribution of antibody to an array of oral bacteria. Altered subclass antibody profiles most often in IgG2 levels and for antibody to P. gingivalis were found related to sex, age, disease severity, race/ethnicity, smoking, and obesity to both pathogens and commensal bacteria.

Unculturable and culturable periodontal-related bacteria are associated with periodontal inflammation during pregnancy and with preterm low birth weight delivery

Recent studies revealed culturable periodontal keystone pathogens are associated with preterm low birth weight (PLBW). However, the oral microbiome is also comprised of hundreds of 'culture-difficult' or 'not-yet-culturable' bacterial species. To explore the potential role of unculturable and culturable periodontitis-related bacteria in preterm low birth weight (PLBW) delivery, we recruited 90 pregnant women in this prospective study. Periodontal parameters, including pocket probing depth, bleeding on probing, and clinical attachment level were recorded during the second trimester and following interviews on oral hygiene and lifestyle habits. Saliva and serum samples were also collected. After delivery, birth results were recorded. Real-time PCR analyses were performed to quantify the levels of periodontitis-related unculturable bacteria (Eubacterium saphenum, Fretibacterium sp. human oral taxon(HOT) 360, TM7 sp. HOT 356, and Rothia dentocariosa), and cultivable bacteria (Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum and Prevotella intermedia) in saliva samples. In addition, ELISA analyses were used to determine the IgG titres against periodontal pathogens in serum samples. Subjects were categorized into a Healthy group (H, n = 20) and periodontitis/gingivitis group (PG, n = 70) according to their periodontal status. The brushing duration was significantly lower in the PG group compared to the H group. Twenty-two of 90 subjects delivered PLBW infants. There was no significant difference in periodontal parameters and serum IgG levels for periodontal pathogens between PLBW and healthy delivery (HD) groups. However, ordinal logistic regression analysis revealed that a higher abundance of Treponema denticola, Prevotella intermedia, Fretibacterium sp. HOT360 and lower levels of Rothia dentocariosa were significantly associated with the presence of periodontal disease during pregnancy. Moreover, the amount of Eubacterium saphenum in saliva and serum IgG against Aggregatibacter actinomycetemcomitans were negatively correlated with PLBW. Taken together, unculturable periodontitis-associated bacteria may play an important role both in the presence of periodontal inflammation during pregnancy and subsequent PLBW.

The relationship between the anti-Porphyromonas gingivalis immunoglobulin G subclass antibody and small for gestational age delivery: a longitudinal study in pregnant Japanese women

BACKGROUND

Maternal serum IgG antibody against Porphyromonas gingivalis is an indicator of both periodontitis and adverse pregnancy outcomes. This study aims to evaluate the anti-P. gingivalis IgG and IgG subclasses1-4 in threatened preterm labour (TPL) patients and their association with small for gestational age (SGA).

METHODS

Serum, saliva and subgingival plaque samples were collected from 47 TPL patients compared with 48 healthy pregnant women. The amount of P. gingivalis was measured in saliva and plaque using real-time polymerase chain reaction. The serum anti-P. gingivalis IgG titre and anti-P. gingivalis subclasses IgG 1-4 concentration were measured using enzyme-linked immunosorbent assay.

RESULTS

The amount of anti-P. gingivalis IgG-1 was significantly lower in the TPL group than in the healthy group. Fourteen subjects delivered SGA infants in the TPL group. The pocket probing depth (PPD), clinical attachment loss, PPD ≥ 5 mm%, amount of P. gingivalis in plaque, anti-P. gingivalis IgG and anti-P. gingivalis IgG-4 were significantly higher in the TPL-SGA group than in the TPL-normal weight group. Moreover, logistic regression analysis revealed the detection frequency of P. gingivalis in plaque and placenta weight were significantly correlated with SGA in TPL. In the receiver operating characteristic curve analysis, an amount of P. gingivalis in plaque ≥ 86.45 copies showed a sensitivity of 0.786 and a specificity of 0.727 (AUC 0.792) for predicting SGA in TPL.

CONCLUSION

Lower anti-P. gingivalis IgG-1 amounts are related to TPL, while higher anti-P. gingivalis IgG and IgG-4 are related with SGA in TPL. Further, greater colonisation of P. gingivalis in plaque might increase the risk of SGA and can be useful in prediction of SGA in TPL.

Heterogeneity of human serum antibody responses to P. gingivalis in periodontitis: Effects of age, race/ethnicity, and sex

Aging humans display an increased prevalence and severity of periodontitis, although the mechanisms underlying these findings remain poorly understood. This report examined antigenic diversity of P. gingivalis related to disease presence and patient demographics. Serum IgG antibody to P. gingivalis strains ATCC33277, FDC381, W50 (ATCC53978), W83, A7A1-28 (ATCC53977) and A7436 was measured in 426 participants [periodontally healthy (n = 61), gingivitis (N = 66) or various levels of periodontitis (N = 299)]. We hypothesized that antigenic diversity in P. gingivalis could contribute to a lack of "immunity" in the chronic infections of periodontal disease. Across the strains, the antibody levels in the oldest age group were lower than in the youngest groups, and severe periodontitis patients did not show higher antibody with aging. While 80 % of the periodontitis patients in any age group showed an elevated response to at least one of the P. gingivalis strains, the patterns of individual responses in the older group were also substantially different than the other age groups. Significantly greater numbers of older patients showed strain-specific antibody profiles to only 1 strain. The findings support that P. gingivalis may demonstrate antigenic diversity/drift within patients and could be one factor to help explain the inefficiency/ineffectiveness of the adaptive immune response in managing the infection.

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.

[Obstructive Sleep disordered breathing, sleep bruxism and periodontal diseases]

Sleep disordered breathing (SDB) may be associated with sleep bruxism and periodontal diseases. Through a review of the current literature, this article aims to describe the characteristics of sleep bruxism and its relationship with SDB as well as the current evidence supporting an association between periodontal diseases and SDB. Sleep bruxism is characterized by muscle clenching and tooth grinding during sleep, typically during N2 sleep stage and in association with micro-arousals. The probability of observing sleep bruxism is almost 4 times higher in the presence of SDB, with a close temporal relationship between the episode of upper airway obstruction or oxygen desaturation and the episode of bruxism, which most often occurs in the 0-10 seconds following the obstruction. These findings support the hypothesis that sleep bruxism is triggered by SDB and may have a "protective" role being a muscular activity that helps restore the permeability of the upper airways. On the other hand, SDB have been linked to periodontal diseases. Periodontal diseases are inflammatory and dysbiotic disorders that can have a negative impact on oral health (leading to the destruction of the periodontium and tooth loss) and on general health. Recently, it has been observed that SDB patients have a 1.6 to 4-fold higher risk of having or developing severe periodontitis, suggesting that SDB may be a new risk factor for periodontal diseases. Dentists, who are part of the team of sleep medicine specialists, have a key role in the detection, prevention and treatment of SDB and their relationship with sleep bruxism and periodontal diseases.

Prevalence of Periodontitis and its Association with Reduced Pulmonary Function: Results from the Korean National Health and Nutrition Examination Survey

Background and Objectives: The current study was performed to evaluate the prevalence of periodontitis and to examine the association between reduced pulmonary function and periodontitis using Sixth Korea National Health and Nutrition Examination Survey (KNHANES) in 2014. Materials and Methods: A cross-sectional evaluation was conducted to estimate the prevalence of periodontitis and to examine the association between periodontitis and reduced pulmonary function while adjusting for sociodemographic characteristics and current smoking status in survey participants between 40 and 79 years old. The presence of periodontitis was evaluated by community periodontal index defined by the World Health Organization, and the assessments of reduced pulmonary function data were made as "normal," "restrictive impairment," or "obstructive impairment." Results: A total of 4004 survey participants representing 25.4 million Koreans were included in the study. Overall, 41.1% of the study population were determined to have periodontitis, and 22.1% had reduced pulmonary function; 7.9% and 14.2% had restrictive- and obstructive- pulmonary impairments, respectively. Age, male gender, and current smoking status were positive predictors for periodontitis. Insurance coverage by workplace and higher education were protective factors against periodontitis. The association between periodontitis and restrictive impairment (adjusted odds ratio (OR) = 1.059, 95% CI 0.729-1.540) or obstructive impairment (adjusted OR = 1.140, 95% CI 0.849-1.530) was not significant. Conclusions: For Koreans, 40-79 years old, age, smoking status, gender, education, and insurance coverage were significant predictors of periodontitis. The prevalence of periodontitis was not significantly associated with reduced pulmonary function. To better understand the relationship between periodontitis and reduced pulmonary function, well-designed and larger scale epidemiologic studies are needed.

Effects of astragaloside IV on inflammation and immunity in rats with experimental periodontitis

This study aimed to investigate the effects of astragaloside IV (AsIV) on inflammation and immunity in rats with experimental periodontitis. Periodontitis was established in 48 Wistar rats, which were then randomly divided into model and 10, 20 and 40 mg/kg AsIV groups, with 12 rats in each group. The latter 3 groups were treated with AsIV at doses of 10, 20 and 40 mg/kg, respectively. The control group (12 rats, without periodontitis) and model group were given the same amount of 5% sodium carboxymethyl cellulose. The treatment was performed once per day for 8 weeks. Before and after treatment, the tooth mobility scores of the rats were determined. After treatment, the salivary occult blood index (SOBI), plaque index (PLI), peripheral blood T lymphocyte subsets, and serum inflammatory factor and immunoglobulin levels were determined. The results showed that, after treatment, compared with that in model group, in 40 mg/kg AsIV group, the general state of rats was improved, while the tooth mobility score, SOBI and PLI were significantly decreased (p < 0.05); the peripheral blood CD4+ T cell percentage and CD4+/CD8+ ratio were significantly increased (p < 0.05), while the CD8+ T cell percentage was significantly decreased (p < 0.05); the serum tumor necrosis factor-α, interleukin-1β and interleukin-2 levels were significantly decreased (p < 0.05); the serum immunoglobulin A and immunoglobulin G levels were significantly decreased (p < 0.05). In conclusion, AsIV can alleviate inflammation and enhance immunity in rats with experimental periodontitis.

Association between oral pathogens and prostate cancer: building the relationship

BACKGROUND

Chronic inflammation and infections are associated with increased risk of prostate cancer development. There is considerable evidence that proves the interrelationship between bacterial/viral infections and carcinogenesis. Periodontitis is a chronic inflammatory disease triggered by gram-negative anaerobic bacteria. In this narrative review, we investigate the relationship between periodontal disease and prostate cancer by reviewing previous studies of the association and possible mechanisms that may explain this link.

METHODS

A comprehensive search for articles published was performed using the key words, "periodontal disease", "prostate disease", "prostate cancer", "prostatic inflammation". Thorough reviews of each study were conducted and assessed for eligibility, and data was summarized.

RESULTS

The role of inflammatory responses in the prostate as drivers of malignancy appears to be predisposed by periodontal pathogens and/or periodontitis inflammatory mediators.

CONCLUSION

Periodontal diseases might be associated with prostate cancer. However, the mechanism(s) explaining this relationship remains unclear and requires further elucidation.

Omega-3 fatty acids suppress Fusobacterium nucleatum-induced placental inflammation originating from maternal endothelial cells

Fusobacterium nucleatum is an oral anaerobe prevalent in intrauterine infection associated with a wide spectrum of adverse pregnancy outcomes. We demonstrate here that F. nucleatum triggers placental inflammation through maternal, rather than paternal, TLR4-mediated signaling. Elimination of TLR4 from maternal endothelial cells alleviated placental inflammation and reduced fetal and neonatal death, while elimination of TLR4 in the hematopoietic cells had no effect. The placental inflammatory response followed a spatiotemporal pattern, with NF-κB activation observed first in the maternal endothelial cells and then in the decidual cells surrounding the endothelium, followed by induction of inflammatory cytokines and chemokines. Supplementation of pregnant mice with fish oil as a source of omega-3 fatty acids suppressed placental inflammation, reduced F. nucleatum proliferation in the placenta, and increased fetal and neonatal survival. In vitro analysis illustrates that omega-3 fatty acids inhibit bacterial-induced inflammatory responses from human umbilical cord endothelial cells. Our study therefore reveals a mechanism by which microbial infections affect pregnancy and identifies a prophylactic therapy to protect against intrauterine infections.

Periodontal diseases and adverse pregnancy outcomes: Is there a role for vitamin D?

Studies have shown a relationship between maternal periodontal diseases (PDs) and premature delivery. PDs are commonly encountered oral diseases which cause progressive damage to the periodontal ligament and alveolar bones, leading to loss of teeth and oral disabilities. PDs also adversely affect general health by worsening of cardiovascular and metabolic diseases. Moreover, maternal PDs are thought to be related to increasing the frequency of preterm-birth with low birth weight (PBLBW) in new-borns. Prematurity and immaturity are the leading causes of prenatal and infant mortality and is a major public health problem around the world. Inflamed periodontal tissues generate significantly high levels of proinflammatory cytokines that may have systemic effects on the host mother and the fetus. In addition, the bacteria that cause PDs produce endotoxins which can harm the fetus. Furthermore, studies have shown that microorganisms causing PDs can get access to the bloodstream, invading uterine tissues, to induce PBLBW. Another likely mechanism that connects PDs with adverse pregnancy outcome is maternal vitamin D status. A role of inadequate vitamin D status in the genesis of PDs has been reported. Administration of vitamin D supplementation during pregnancy could reduce the risk of maternal infections and adverse pregnancy outcomes. As maternal PDs are significant risk factors for adverse pregnancy outcome, preventive antenatal care for pregnant women in collaboration with the obstetric and dental professions are required.

Ageing effects on humoral immune responses in chronic periodontitis

Periodontal disease is a dominant global bacterial infection that increases with ageing.

AIM

This report focuses on host adaptive immune responses in periodontitis. While experimental models and humans diagnosed with periodontitis demonstrate an antigenic specificity for particular oral bacteria, we have a limited understanding of (i) how ageing affects the adaptive immune responses to these bacteria that chronically colonize the oral cavity for decades prior to disease expression and (ii) how the magnitude and specificity of the response interface with pathogens that emerge within the bacterial ecology during exacerbations of disease.

MATERIALS AND METHODS

Serum antibody levels to a group of pathogenic and commensal oral bacteria were measured in a population of individuals from 21 to 74 years of age, stratified based on clinical status of the periodontium, smoking and sex.

RESULTS

Clinical parameters were not significantly different within health, gingivitis or periodontitis groups related to age. Antibody to oral pathogens and commensals was similar in different age groups in each of the clinical categories, with no age correlation noted in the periodontitis patients.

CONCLUSIONS

The adaptive immune responses to oral bacteria that chronically colonize the oral cavity appear generally unaffected by age, but clearly are linked to the extent of disease.

Fusobacterium nucleatum and adverse pregnancy outcomes: Epidemiological and mechanistic evidence

Fusobacterium nucleatum is a Gram-negative anaerobic oral commensal associated with periodontal disease. F. nucleatum has been implicated in a wide spectrum of systemic diseases, including oral, gastro-intestinal, rheumatologic, and vascular pathologies. As pregnancy risk has been linked to periodontal disease, there has also been significant research into the effects of periodontal disease on adverse pregnancy outcomes. This article reviews the epidemiological and mechanistic evidence of the role of F. nucleatum in adverse pregnancy outcomes.

Simultaneous Detection of Oral Pathogens in Subgingival Plaque and Prostatic Fluid of Men With Periodontal and Prostatic Diseases

BACKGROUND

Chronic prostatitis (CPr) and benign prostatic hyperplasia (BPH) are complex inflammatory conditions for which etiologic determinants are still poorly defined. Periodontitis is caused by subgingival colonizing bacteria in the oral cavity. The causal effect of periodontal disease on prostatic inflammation has not been established. The purpose of this study is to isolate oral pathogens from expressed prostatic secretions of patients with periodontal disease and CPr or BPH.

METHODS

Twenty-four men diagnosed with CPr/BPH participated in the study. A complete periodontal examination consisting of probing depth, bleeding on probing, tooth mobility, gingival index, and plaque index was performed on the men, and prostatic secretion was collected for the study. Dental plaque and prostatic secretion samples were used for analysis of bacterial DNA for Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Treponema denticola (Td), and Escherichia coli using reverse transcription-polymerase chain reaction.

RESULTS

Six patients were diagnosed with severe, seven with moderate, and four with mild chronic periodontitis. Seventeen of 24 (70.8%) of the prostatic secretion samples showed one or more of the studied oral pathogens. Nine of 10 BPH and eight of 14 patients with CPr had at least one oral pathogen in their prostatic secretions. Pg was found in both prostatic secretion and plaque samples in six of 17 (35.3%) patients, Td was found in both samples in seven of 15 (46.7%) patients, and E. coli was found in both samples in three of 15 (20%) patients. Pi was detected in all dental plaque samples but not in the prostatic secretion.

CONCLUSION

An association between chronic inflammatory prostate and periodontal diseases has been demonstrated by the presence of similar bacterial DNA in both prostatic secretion and subgingival dental plaque from the same individual.

Association Between Asthma and Periodontitis: Results From the Korean National Health and Nutrition Examination Survey

BACKGROUND

The aim of this study is to examine the association between asthma and periodontitis in a representative sample of Korean adults from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES) in 2014.

METHODS

This study conducts a cross-sectional evaluation using 2014 KNHANES data to describe the association between current asthma condition and chronic periodontitis while adjusting for sociodemographic characteristics and lifestyle factors. Presence of periodontitis is evaluated by community periodontal index defined by the World Health Organization, and current asthma condition is defined as "currently suffering from asthma condition."

RESULTS

The study population comprises a total of 5,976 patients aged 19 years and older, representing 40.7 million Koreans. A multivariable logistic regression analysis with weighted observations reveals patients with current asthma condition are ≈5 times more likely to be associated with periodontitis (adjusted odds ratio [OR]: 5.36; 95% confidence interval [95% CI]: 1.27 to 22.68). In addition, 83% of patients who regularly receive scheduled antiasthmatic medications are less likely to have a diagnosis of periodontitis than individuals who do not receive medication regularly (adjusted OR: 0.17; 95% CI: 0.05 to 0.57). However, the association is not significant if treatment with antiasthmatic medication is delivered on an "as-needed" basis (adjusted OR:1.80; 95% CI: 0.87 to 3.74).

CONCLUSIONS

Findings from the current study show a positive association between periodontitis and current asthma condition. In addition, patients taking scheduled antiasthmatic medications are less likely to be diagnosed with periodontitis. Due to limitations of study design and available data from the national survey, well-designed follow-up studies are needed to confirm these findings.

Integrated biomarker profiling of smokers with periodontitis

BACKGROUND

In the context of precision medicine, understanding patient-specific variation is an important step in developing targeted and patient-tailored treatment regimens for periodontitis. While several studies have successfully demonstrated the usefulness of molecular expression profiling in conjunction with single classifier systems in discerning distinct disease groups, the majority of these studies do not provide sufficient insights into potential variations within the disease groups.

AIM

The goal of this study was to discern biological response profiles of periodontitis and non-periodontitis smoking subjects using an informed panel of biomarkers across multiple scales (salivary, oral microbiome, pathogens and other markers).

MATERIAL & METHODS

The investigation uses a novel ensemble classification approach (SVA-SVM) to differentiate disease groups and patient-specific biological variation of systemic inflammatory mediators and IgG antibody to oral commensal and pathogenic bacteria within the groups.

RESULTS

Sensitivity of SVA-SVM is shown to be considerably higher than several traditional independent classifier systems. Patient-specific networks generated from SVA-SVM are also shown to reveal crosstalk between biomarkers in discerning the disease groups. High-confidence classifiers in these network abstractions comprised of host responses to microbial infection elucidated their critical role in discerning the disease groups.

CONCLUSIONS

Host adaptive immune responses to the oral colonization/infection contribute significantly to creating the profiles specific for periodontitis patients with potential to assist in defining patient-specific risk profiles and tailored interventions.

Adverse pregnancy outcomes (APOs) and periodontal disease: pathogenic mechanisms

AIM

To evaluate the evidence on potential biological pathways underlying the possible association between periodontal disease (PD) and adverse pregnancy outcomes (APOs).

MATERIAL & METHODS

Human, experimental and in vitro studies were evaluated.

RESULTS

Periodontal pathogens/byproducts may reach the placenta and spread to the foetal circulation and amniotic fluid. Their presence in the foeto-placental compartment can stimulate a foetal immune/inflammatory response characterized by the production of IgM antibodies against the pathogens and the secretion of elevated levels of inflammatory mediators, which in turn may cause miscarriage or premature birth. Moreover, infection/inflammation may cause placental structural changes leading to pre-eclampsia and impaired nutrient transport causing low birthweight. Foetal exposure may also result in tissue damage, increasing the risk for perinatal mortality/morbidity. Finally, the elicited systemic inflammatory response may exacerbate local inflammatory responses at the foeto-placental unit and further increase the risk for APOs.

CONCLUSIONS

Further investigation is still necessary to fully translate the findings of basic research into clinical studies and practice. Understanding the systemic virulence potential of the individual's oral microbiome and immune response may be a distinctly different issue from categorizing the nature of the challenge using clinical signs of PD. Therefore, a more personalized targeted therapy could be a more predictive answer to the current "one-size-fits-all" interventions.

Adverse pregnancy outcomes (APOs) and periodontal disease: pathogenic mechanisms

AIM

To evaluate the evidence on potential biological pathways underlying the possible association between periodontal disease (PD) and adverse pregnancy outcomes (APOs).

MATERIAL & METHODS

Human, experimental and in vitro studies were evaluated.

RESULTS

Periodontal pathogens/byproducts may reach the placenta and spread to the foetal circulation and amniotic fluid. Their presence in the foeto-placental compartment can stimulate a foetal immune/inflammatory response characterized by the production of IgM antibodies against the pathogens and the secretion of elevated levels of inflammatory mediators, which in turn may cause miscarriage or premature birth. Moreover, infection/inflammation may cause placental structural changes leading to pre-eclampsia and impaired nutrient transport causing low birthweight. Foetal exposure may also result in tissue damage, increasing the risk for perinatal mortality/morbidity. Finally, the elicited systemic inflammatory response may exacerbate local inflammatory responses at the foeto-placental unit and further increase the risk for APOs.

CONCLUSIONS

Further investigation is still necessary to fully translate the findings of basic research into clinical studies and practice. Understanding the systemic virulence potential of the individual's oral microbiome and immune response may be a distinctly different issue from categorizing the nature of the challenge using clinical signs of PD. Therefore, a more personalized targeted therapy could be a more predictive answer to the current "one-size-fits-all" interventions.

Effect of maternal periodontitis and low birth weight--a case control study

INTRODUCTION

Since the 1990s, evidence has been raised that there is an association between maternal periodontal disease and undesirable gestational events, for example low birth weight; this issue is controversial.

OBJECTIVE

To evaluate whether there is an association between maternal periodontitis and low birth weight (LBW).

METHODS

A case-control study was carried out on 951 mothers that had been cared for by the Brazilian Unified Health System in Petrolina-PE and Juazeiro-BA, Brazil. The case group (n = 269) consisted of mothers of newborns with birth weight <2500 g and a control group (n = 682) of mothers of newborns with birth weight ≥2500 g. An interview was realized, using a questionnaire as well as a full mouth examination to diagnose the periodontal condition. Women who had at least four teeth with probing depth ≥4 mm and clinical attachment loss ≥3 mm, with bleeding on probing at the same site, were diagnosed with periodontitis. The birth weight was obtained through the hospital book record. The main association was evaluated using the multivariate regression model, considering confounders.

RESULTS

The frequency of periodontitis was 16.4% (case group) and 17.4% (control group). Periodontitis did not show an association with LBW (ORcrude = 0.92; 95% CI = 0.63-1.35), even after adjustment for the following confounders: maternal age, pre-gestational body mass index, number of pre-natal consultations, number of pregnancies, maternal schooling level, smoking habit during pregnancy and hypertension (ORadjusted = 1.00; 95% CI = 0.61-1.68).

CONCLUSION

The findings of this study showed no association between maternal periodontal disease and low birth weight, even after appropriate adjustments for confounding factors.

Anti-HmuY antibodies specifically recognize Porphyromonas gingivalis HmuY protein but not homologous proteins in other periodontopathogens

Given the emerging evidence of an association between periodontal infections and systemic conditions, the search for specific methods to detect the presence of P. gingivalis, a principal etiologic agent in chronic periodontitis, is of high importance. The aim of this study was to characterize antibodies raised against purified P. gingivalis HmuY protein and selected epitopes of the HmuY molecule. Since other periodontopathogens produce homologs of HmuY, we also aimed to characterize responses of antibodies raised against the HmuY protein or its epitopes to the closest homologous proteins from Prevotella intermedia and Tannerella forsythia. Rabbits were immunized with purified HmuY protein or three synthetic, KLH-conjugated peptides, derived from the P. gingivalis HmuY protein. The reactivity of anti-HmuY antibodies with purified proteins or bacteria was determined using Western blotting and ELISA assay. First, we found homologs of P. gingivalis HmuY in P. intermedia (PinO and PinA proteins) and T. forsythia (Tfo protein) and identified corrected nucleotide and amino acid sequences of Tfo. All proteins were overexpressed in E. coli and purified using ion-exchange chromatography, hydrophobic chromatography and gel filtration. We demonstrated that antibodies raised against P. gingivalis HmuY are highly specific to purified HmuY protein and HmuY attached to P. gingivalis cells. No reactivity between P. intermedia and T. forsythia or between purified HmuY homologs from these bacteria and anti-HmuY antibodies was detected. The results obtained in this study demonstrate that P. gingivalis HmuY protein may serve as an antigen for specific determination of serum antibodies raised against this bacterium.

Fap2 of Fusobacterium nucleatum is a galactose-inhibitable adhesin involved in coaggregation, cell adhesion, and preterm birth

Fusobacterium nucleatum is a common oral anaerobe involved in periodontitis that is known to translocate and cause intrauterine infections. In the oral environment, F. nucleatum adheres to a large diversity of species, facilitating their colonization and creating biological bridges that stabilize the multispecies dental biofilm. Many of these interactions (called coadherences or coaggregations) are galactose sensitive. Galactose-sensitive interactions are also involved in the binding of F. nucleatum to host cells. Hemagglutination of some F. nucleatum strains is also galactose sensitive, suggesting that a single galactose-sensitive adhesin might mediate the interaction of fusobacteria with many partners and targets. In order to identify the fusobacterial galactose-sensitive adhesin, a system for transposon mutagenesis in fusobacteria was created. The mutant library was screened for hemagglutination deficiency, and three clones were isolated. All three clones were found to harbor the transposon in the gene coding for the Fap2 outer membrane autotransporter. The three fap2 mutants failed to show galactose-inhibitable coaggregation with Porphyromonas gingivalis and were defective in cell binding. A fap2 mutant also showed a 2-log reduction in murine placental colonization compared to that of the wild type. Our results suggest that Fap2 is a galactose-sensitive hemagglutinin and adhesin that is likely to play a role in the virulence of fusobacteria.

Comparative analysis of gingival tissue antigen presentation pathways in ageing and periodontitis

AIM

Gingival tissues of periodontitis lesions contribute to local elevations in mediators, including both specific T cell and antibody immune responses to oral bacterial antigens. Thus, antigen processing and presentation activities must exist in these tissues to link antigen-presenting cells with adaptive immunity. We hypothesized that alterations in the transcriptome of antigen processing and presentation genes occur in ageing gingival tissues and that periodontitis enhances these differences reflecting tissues less capable of immune resistance to oral pathogens.

MATERIALS AND METHODS

Rhesus monkeys (n = 34) from 3 to 23 years of age were examined. A buccal gingival sample from healthy or periodontitis sites was obtained, total RNA isolated, and microarray analysis was used to describe the transcriptome.

RESULTS

The results demonstrated increased transcription of genes related to the MHC class II and negative regulation of NK cells with ageing in healthy gingival tissues. In contrast, both adult and ageing periodontitis tissues showed decreased transcription of genes for MHC class II antigens, coincident with up-regulation of MHC class I-associated genes.

CONCLUSION

These transcriptional changes suggest a response of healthy ageing tissues through the class II pathway (i.e. endocytosed antigens) and altered responses in periodontitis that could reflect host-associated self-antigens or targeting cytosolic intracellular microbial pathogens.

Anticardiolipin in porphyromonas gingivalis antisera causes fetal loss in mice

β2-glycoprotein I (β2GPI)-dependent anticardiolipin autoantibodies (aCl) are associated with thrombosis and fetal loss. Some microbial pathogens can induce pathogenic antibodies cross-reactive with β2GPI. Sera from a significant percentage of periodontitis patients contain aCl, and some periodontal pathogens contain antigens with peptide sequences having homology to β2GPI. We hypothesized that antibodies raised against P. gingivalis (aPg) contain pathogenic aCl that induce fetal resorption. We immunized mice with β2GPI, P. gingivalis W83, or an arg-gingipain-defective mutant of P. gingivalis (HF18). IgG fractions of aPg were immunoabsorbed to remove aCl-like antibodies (abs-aPg). IgG fractions were administered intravenously into tail veins of mated BALB/c females at day 0 of pregnancy. At day 15, the proportions of fetal resorptions were evaluated. The prevalence of fetal loss was significantly greater in the aPg group than in the control IgG group (21.2% vs. 5.3%, p = .001), and greater in the aPg group than in the abs-aPg group (21.2% vs. 12%, p < .05). There were no fetal resorptions observed in the aPgHF18 group (p = .0005 compared with aPg, p = .17 compared with control). aPg antibody contains activity consistent with pathogenic aCl, and the antigen inducing the antibodies that cause increased fetal loss may be on the arg-gingipain protease of P. gingivalis.

Association of a common genetic factor, PTGER3, with outcome of periodontal therapy and preterm birth

BACKGROUND

Clinical evidence suggests an association between preterm birth and periodontal disease. This study explores whether specific genetic polymorphisms are associated with success of periodontal therapy in pregnant women with periodontal disease and, further, whether any of these same polymorphisms are also associated with spontaneous preterm birth (sPTB).

METHODS

One hundred sixty high-risk pregnant women (6 to 20 weeks of gestation) with periodontal disease (≥ 3 sites with attachment loss ≥ 4 mm) were studied. All women received scaling and root planing plus oral hygiene instruction. Periodontal examinations were performed before treatment and 20 weeks later. Participants were classified according to two study outcomes: 1) success or failure of periodontal treatment; and 2) presence or absence of sPTB. Maternal DNA samples from mucosal swabs were characterized using a 1536-SNP (single-nucleotide polymorphism) custom polymerase chain reaction chip. A probabilistic model of each dichotomous outcome, derived using a stepwise Bayesian procedure, was compared to respective null hypotheses on the basis of Monte Carlo simulations and significance estimates obtained using three measures (z-test, Welch t-test, and probability convolution). The models were further confirmed by logistic regression analyses.

RESULTS

The models revealed a significant relation between a specific polymorphism of prostaglandin E receptor 3 (a gene associated with inflammatory response) and both periodontal treatment failure (odds ratio 11.09, P <0.0002) and sPTB (odds ratio 6.89, P < 0.0032).

CONCLUSIONS

These results demonstrate that the risk of unsuccessful periodontal treatment is associated with tag SNPs in specific genes that regulate the inflammatory response, one of which is also associated with sPTB.

State of the science: chronic periodontitis and systemic health

CONTEXT

Inflammatory periodontal diseases exhibit an association with multiple systemic conditions. Currently, there is a lack of consensus among experts on the nature of these associations and confusion among health care providers and the public on how to interpret this rapidly growing body of science. This article overviews the current evidence linking periodontal diseases to diabetes, cardiovascular disease, osteoporosis, preterm low birth weight babies, respiratory diseases, and rheumatoid arthritis.

EVIDENCE ACQUISITION

Evidence was taken from systematic reviews, clinical trials, and mechanistic studies retrieved in searches of the PubMed electronic database. The available data provide the basis for applied practical clinical recommendations.

EVIDENCE SYNTHESIS

Evidence is summarized and critically reviewed from systematic reviews, primary clinical trials, and mechanistic studies

CONCLUSIONS

Surrogate markers for chronic periodontitis, such as tooth loss, show relatively consistent but weak associations with multiple systemic conditions. Despite biological plausibility, shorter-term interventional trials have generally not supported unambiguous cause-and-effect relationships. Nevertheless, the effective treatment of periodontal infections is important to achieve oral health goals, as well as to reduce the systemic risks of chronic local inflammation and bacteremias. Inflammatory periodontal diseases exhibit an association with multiple systemic conditions. With pregnancy as a possible exception, the local and systemic effects of periodontal infections and inflammation are usually exerted for many years, typically among those who are middle-aged or older. It follows that numerous epidemiological associations linking chronic periodontitis to age-associated and biologically complex conditions such as diabetes, cardiovascular disease, osteoporosis, respiratory diseases, rheumatoid arthritis, certain cancers, erectile dysfunction, kidney disease and dementia, have been reported. In the coming years, it seems likely that additional associations will be reported, despite adjustments for known genetic, behavioral and environmental confounders. Determining cause-and-effect mechanisms is more complicated, especially in circumstances where systemic effects may be subtle. Currently, however, there is a lack of consensus among experts on the nature of these associations and confusion among health care providers and the public on how to interpret this rapidly growing body of science. This article overviews the current evidence linking periodontal diseases to diabetes, cardiovascular disease, osteoporosis, preterm/low birth weight babies, respiratory diseases, and rheumatoid arthritis.

Association of pregnant women periodontal status to preterm and low-birth weight babies: A systematic and evidence-based review

The mouth serves as a mirror to general health and also as a portal for disease to the rest of the body. Since the old wives' tale of "the loss of a tooth for every pregnancy", oral health during pregnancy has long been a focus of interest. In the past decade, there has been mounting scientific evidence suggesting that periodontal disease may play an important role as a risk factor for adverse pregnancy outcomes. Considering all the above stated factors this systematic review is aimed to focus on the association of periodontal diseases to preterm and low-birth weight (LBW) babies. In view of the large body of literature the review is limited to studies identified by computer searching. Hand searching of journals and gathering of unpublished reports and conference proceedings was outside the scope of the review. The PubMed database was searched using the search terms: periodontitis, preterm, LBW. The titles, authors, and abstracts from all studies identified by the electronic search were printed and reviewed independently on the basis of keywords, title and abstract, to determine whether these met the inclusion criteria. The electronic search identified 68 papers. After review of the study title, keywords and abstracts, 62 papers were identified potentially meeting inclusion criteria. Generally, all the studies reviewed in the paper suggest that periodontal disease may be a potential risk factor for preterm LBW babies.

Transition metal ions induce carnosinase activity in PepD-homologous protein from Porphyromonas gingivalis

Aminoacylhistidine dipeptidase (EC 3.4.13.3; also Xaa-His dipeptidase, carnosinase, or PepD) catalyzes the cleavage and release of an N-terminal amino acid, which is usually a neutral or hydrophobic residue, from an Xaa-His dipeptide or degraded peptide fragment. PepD enzyme is found extensively in prokaryotes and eukaryotes, and belongs to the metallopeptidase family M20, a part of the metallopeptidase H (MH) clan. Carnosine is a naturally occurring dipeptide (β-alanyl-l-histidine) present in mammalian tissues that has protective functions in addition to anti-oxidant and free-radical scavenging roles. During bacterial infections, degradation of l-carnosine via carnosinase or PepD-like enzymes may enhance the destructive potential of bacteria, resulting in a pathological impact. This process has been proposed to act in an anti-oxidant manner in vivo. In the present study, the recombinant PepD protein encoded by Porphyromonas gingivalis TDC60 pepD was generated and biochemically characterized. In addition, a recombinant dipeptidase enzyme was found to function not only as an alanine-aminopeptidase, but also as a carnosinase. Furthermore, when carnosine was used as substrate for PepD, the transition metals, Mn(2+), Fe(2+), Co(2+), and Ni(2+) stimulated the hydrolyzing activity of rPepD with β-alanine and l-histidine. Based on its metal ion specificity, we propose that this enzyme should not only be termed l-aminopeptidase, but also a carnosinase.

Birth weight of infants of mothers with aggressive periodontitis

BACKGROUND

It was hypothesized that if periodontal infections predispose low birth weights and premature birth, then such outcomes should be apparent when the mother has aggressive periodontitis (AgP).

METHODS

Birth weight data were collected by questionnaire from females with AgP, their periodontally healthy siblings, and unrelated periodontally healthy women. Both prospective and retrospective birth outcome data were used. Because many of the periodontal evaluations were performed after the births, there were incomplete data regarding most of the risk factors for low birth weight. We determined associations between mothers' periodontal diagnoses and clinical variables and the reported birth weights.

RESULTS

There were no significant differences in mean birth weights of babies born to control subjects or AgP patients. This was true whether all the births were considered or only those reported <1 or 2 years before periodontal examination. For periodontally healthy controls, 13.2% of babies born to siblings of AgP patients and 12.8% of babies born to unrelated mothers weighed <2,500 g, whereas 9.9% of those born to mothers with generalized AgP and 10.3% of those born to mothers with localized AgP weighed <2,500 g.

CONCLUSIONS

Because of the relative rarity of AgP in the population, and attendant difficulties in performing a prospective study of its association with pregnancy outcomes, we used a compromised approach using prospective data as well as weaker retrospective data assuming that disease onset was likely before the births. Our results, within the limitations of this approach, indicate no evidence that AgP in the mother predisposes low birth weights. AgP has many unique biologic characteristics that differentiate it from chronic forms of periodontal disease, and the possible lack of its association with birth weight may be another such characteristic.

Association between periodontal disease, bacterial vaginosis, and sexual risk behaviours

BACKGROUND

Both periodontal disease and bacterial vaginosis may cause adverse pregnancy outcomes. This study evaluated the association between periodontal disease and bacterial vaginosis.

MATERIALS AND METHODS

Data from 3569 women enrolled in the Longitudinal Study of Vaginal Flora were used. Periodontal disease, defined as greater than three sites with ≥4 mm attachment loss, was assessed by specially calibrated hygienists at baseline. Positive bacterial vaginosis status was based on a Nugent Gram stain score ≥7. Pairs of independent variables were compared with Pearson's χ(2) and risk ratios were calculated through log-binomial regression.

RESULTS

Twenty-eight per cent of women with bacterial vaginosis had periodontal disease compared with 22% without , corresponding to 1.29 (95% CI: 1.13, 1.47) times greater risk of periodontal disease among women with bacterial vaginosis. In adjusted analysis the risk ratio dropped to 1.23 (95% CI: 1.08, 1.40). Receptive oral sex with an uncircumcised partner was associated with 1.28 times (95% CI: 0.97, 1.69) the risk for periodontal disease compared with receptive oral sex with a circumcised partner, though the association is not statistically significant.

CONCLUSIONS

In this population, there is a small but significant association between periodontal disease and bacterial vaginosis and a possible trend between receptive oral sex with an uncircumcised partner and periodontal disease.

Periodontal infection and preterm birth: successful periodontal therapy reduces the risk of preterm birth

OBJECTIVE

This study tested the hypothesis that successful periodontal treatment was associated with a reduction in the incidence of spontaneous preterm birth (PTB).

DESIGN

This was a randomised, controlled, blinded clinical trial.

SETTING

Hospital outpatient clinic.

POPULATION

Pregnant women of 6-20 weeks of gestation were eligible.

METHODS

Of 322 pregnant women with periodontal disease, 160 were randomly assigned to receive scaling and root planing (SRP, cleaning above and below the gum line), plus oral hygiene instruction, whereas the remaining 162 received only oral hygiene instruction and served as an untreated control group. Subjects received periodontal examinations before and 20 weeks after SRP, and were classified blindly according to the results of treatment into two groups: successful ('non-exposure') and unsuccessful ('exposure') treatment. Groups were compared using standard inferential statistics; dichotomous variables were compared using the chi-square test or logistic regression. Results are presented in terms of odds ratios.

MAIN OUTCOME MEASURE

The main outcome measure was spontaneous preterm birth before 35 weeks of gestation.

RESULTS

No significant difference was found between the incidence of PTB in the control group (52.4%; n = 162) and the periodontal treatment group (45.6%; n = 160) (P < 0.13, Fisher's exact test). The incidence of PTB was compared within the periodontal treatment group, considering the success of therapy. A logistic regression analysis showed a strong and significant relationship between successful periodontal treatment and full-term birth (adjusted odds ratio 6.02; 95% CI 2.57-14.03). Subjects refractory to periodontal treatment were significantly more likely to have PTB.

CONCLUSIONS

A beneficial effect on PTB may be dependent on the success of periodontal treatment.

HIV-1 reactivation induced by the periodontal pathogens Fusobacterium nucleatum and Porphyromonas gingivalis involves Toll-like receptor 2 [corrected] and 9 activation in monocytes/macrophages

Although oral coinfections (e.g., periodontal disease) are highly prevalent in human immunodeficiency virus type 1-positive (HIV-1(+)) patients and appear to positively correlate with viral load levels, the potential for oral bacteria to induce HIV-1 reactivation in latently infected cells has received little attention. We showed that HIV-1 long terminal repeat (LTR) promoter activation can be induced by periodontopathogens in monocytes/macrophages; nevertheless, the mechanisms involved in this response remain undetermined. Since Toll-like receptor 2 (TLR2), TLR4, and TLR9 activation have been involved in HIV-1 recrudescence, we sought to determine the role of these TLRs in HIV-1 reactivation induced by the periodontal pathogens Fusobacterium nucleatum and Porphyromonas gingivalis using BF24 monocytes/macrophages stably transfected with the HIV-1 promoter driving chloramphenicol acetyltransferase (CAT) expression and THP89GFP cells, a model of HIV-1 latency. We demonstrated that TLR9 activation by F. nucleatum and TLR2 activation by both bacteria appear to be involved in HIV-1 reactivation; however, TLR4 activation had no effect. Moreover, the autocrine activity of tumor necrosis factor alpha (TNF-alpha) but not interleukin-1beta (IL-1beta) produced in response to bacteria could impact viral reactivation. The transcription factors NF-kappaB and Sp1 appear to be positively regulating HIV-1 reactivation induced by these oral pathogens. These results suggest that oral Gram-negative bacteria (F. nucleatum and P. gingivalis) associated with oral and systemic chronic inflammatory disorders enhance HIV-1 reactivation in monocytes/macrophages through TLR2 and TLR9 activation in a mechanism that appears to be transcriptionally regulated. Increased bacterial growth and emergence of these bacteria or their products accompanying chronic oral inflammatory diseases could be risk modifiers for viral replication, systemic immune activation, and AIDS progression in HIV-1(+) patients.