Estimation of serum antibody to subgingival species using checkerboard immunoblotting

Antibodies to oral pathobionts and colon cancer risk in the CLUE I cohort study

Periodontitis has been associated with an increased risk for gastrointestinal cancers. The objective of our study was to investigate the association of antibodies to oral bacteria and the risk of colon cancer in a cohort setting. Using the CLUE I cohort, a prospective cohort initiated in 1974 in Washington County, Maryland, we conducted a nested case-control study to examine the association of levels of IgG antibodies to 11 oral bacterial species (13 total strains) with risk of colon cancer diagnosed a median of 16 years later (range: 1-26 years). Antibody response was measured using checkerboard immunoblotting assays. We included 200 colon cancer cases and 200 controls matched on age, sex, cigarette smoking status, time of blood draw and pipe or cigar smoking status. Controls were selected using incidence density sampling. Conditional logistic regression models were used to assess the association between antibody levels and colon cancer risk. In the overall analysis, we observed significant inverse associations for 6 of the 13 antibodies measured (P-trends <.05) and one positive association for antibody levels to Aggregatibacter actinomycetemcomitans (ATCC 29523; P-trend = .04). While we cannot rule out a role for periodontal disease in colon cancer risk, findings from our study suggest that a strong adaptive immune response may be associated with a lower risk of colon cancer. More studies will need to examine whether the positive associations we observed with antibodies to A. actinomycetemcomitans reflect a true causal association for this bacterium.

Association of Dental Infections with Intracranial Atherosclerotic Stenosis

INTRODUCTION

Periodontal disease (PD) and dental caries are oral infections leading to tooth loss that are associated with atherosclerosis and cerebrovascular disease. We assessed the hypothesis that PD and caries are associated with asymptomatic intracranial atherosclerosis (ICAS) in the Atherosclerosis Risk in Communities (ARIC) study.

METHODS

Full-mouth clinical periodontal measurements (7 indices) collected at 6 sites per tooth from 6,155 subjects from the Dental Atherosclerosis Risk in Communities Study (DARIC) without prior stroke were used to differentiate seven PD stages (Periodontal Profile Class [PPC]-I to -VII) and dental caries on coronal dental surface (DS) and dental root surface (DRS). A stratified subset underwent 3D time-of-flight MR angiogram and 3D high isotropic-resolution black blood MRI. ICAS was graded according to the criteria established by the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. We evaluated the relationship between PD stage and dental caries with asymptomatic ICAS, graded as no ICAS, <50% ICAS, and ≥50% ICAS.

RESULTS

Among dentate subjects who underwent vascular imaging, 801 (70%) had no ICAS, 232 (20%) had <50% ICAS, and 112 (10%) had ≥50% ICAS. Compared to participants without gum disease (PPC-I), participants with mild-moderate tooth loss (PPC-VI), severe tooth loss (PPC-VII), and severe PD (PPC-IV) had higher odds of having <50% ICAS. Participants with extensive gingivitis (PPC-V) had significantly higher odds of having ≥50% ICAS. This association remained significant after adjusting for confounding variables: age, gender, race, hypertension, diabetes, dyslipidemia, 3-level education, and smoking status. There was no association between dental caries (DS and DRS) and ICAS <50% and ≥50%.

CONCLUSION

We report significant associations between mild-moderate tooth loss, severe tooth loss, and severe PD with <50% ICAS as well as an association between extensive gingivitis and ≥50% ICAS. We did not find an association between dental caries and ICAS.

Antibodies against Periodontal Microorganisms and Cognition in Older Adults

INTRODUCTION

Markers of poor oral health are associated with impaired cognition and higher risk of Alzheimer disease (AD) and thus may help predict AD.

OBJECTIVES

The aim of this study was to evaluate the cross-sectional association between empirically derived groups of 19 IgG antibodies against periodontal microorganisms and cognition in middle-aged and older adults.

METHODS

The study population consisted of participants of the third National Health and Nutrition Examination Survey (NHANES III) (1988 to 1994), who were 60 y and older, among whom cognition and IgG antibodies against 19 periodontal microorganisms were measured (N = 5,162).

RESULTS

In multivariable quantile regression analyses, the Orange-Red (Prevotella melaninogenica, Prevotella intermedia, Prevotella nigrescens, Porphyromonas gingivalis) and Yellow-Orange (Staphylococcus intermedius, Streptococcus oralis, Streptococcus mutans, Fusobacterium nucleatum, Peptostreptococcus micros, Capnocytophaga ochracea) cluster scores were negatively associated with cognition. A 1-unit higher cluster score for the Orange-Red cluster was associated on average with a lower cognitive score (β for 30th quantile = -0.2640; 95% confidence interval [CI], -0.3431 to -0.1848). Similarly, a 1-unit higher score for the Yellow-Orange cluster was associated with a lower cognitive score (β for 30th quantile = -0.2445; 95% CI, -0.3517 to -0.1372).

CONCLUSION

Groups of IgG antibodies against periodontal microorganisms were associated with lower cognition among free living adults 60 years and older, who were previously undiagnosed with cognitive impairment. Though poor oral health precedes the development of dementia and AD, oral health information is currently not used, to our knowledge, to predict dementia or AD risk. Combining our findings with current algorithms may improve risk prediction for dementia and AD.

KNOWLEDGE TRANSLATION STATEMENT

IgG antibodies against periodontal microorganisms were associated with lower cognition among adults 60 years and older previously undiagnosed with cognitive impairment. Periodontal disease may predict cognition among older adults.

Association between the quality of plant-based diets and periodontitis in the U.S. general population

AIM

To investigate the relationship between plant-based diet indices (PDIs) and periodontitis and serum IgG antibodies against periodontopathogens in the U.S.

POPULATION

MATERIALS AND METHODS

We analysed cross-sectional data on 5651 participants ≥40 years of age from the Third National Health and Nutrition Examination Survey. Food frequency questionnaire data were used to calculate the overall PDI, healthy plant-based diet index (hPDI), and unhealthy plant-based diet index (uPDI). Periodontitis was defined using a half-reduced Centers for Disease Control and Prevention and American Academy of Periodontology case definition. Serum antibodies against 19 periodontopathogens were used to classify the population into two subgroups using hierarchical clustering. Survey-weighted multivariable logistic regressions were applied to assess the associations of PDI/hPDI/uPDI z-scores with periodontitis and hierarchical clusters after adjusting for potential confounders.

RESULTS

A total of 2841 (50.3%) participants were defined as having moderate/severe periodontitis. The overall PDI z-score was not significantly associated with the clinical and bacterial markers of periodontitis. By considering the healthiness of plant foods, we observed an inverse association between hPDI z-score and periodontitis (odds ratio [OR] = 0.925, 95% confidence interval [CI]: 0.860-0.995). In contrast, higher uPDI z-score (adherence to unhealthful plant foods) might increase the risk of periodontitis (OR = 1.100; 95% CI: 1.043-1.161). Regarding antibodies against periodontopathogens, the participants in cluster 2 had higher periodontal antibodies than those in cluster 1. The hPDI z-score was positively associated with cluster 2 (OR = 1.192; 95% CI: 1.112-1.278). In contrast, an inverse association between uPDI z-score and cluster 2 was found (OR = 0.834; 95% CI: 0.775-0.896).

CONCLUSIONS

Plant-based diets were associated with periodontitis, depending on their quality. A healthy plant-based diet was inversely related to an increased risk of periodontitis but positively related to elevated antibody levels against periodontopathogens. For an unhealthy plant-based diet, the opposite trends were observed.

Oral Microbiota Profile in Patients with Anti-Neutrophil Cytoplasmic Antibody–Associated Vasculitis

Microbiota has been associated with autoimmune diseases, with nasal Staphylococcus aureus being implicated in the pathogenesis of anti-neutrophil cytoplasmic antibody-associated vasculitis (AAV). Little is known about the role of oral microbiota in AAV. In this study, levels of IgG antibodies to 53 oral bacterial species/subspecies were screened using immunoblotting in plasma/serum in pre-symptomatic AAV-individuals (n = 85), matched controls, and established AAV-patients (n = 78). Saliva microbiota from acute-AAV and controls was sequenced from 16s rDNA amplicons. Information on dental status was extracted from a national register. IgG levels against oral bacteria were lower in established AAV versus pre-AAV and controls. Specifically, pre-AAV samples had, compared to controls, a higher abundance of periodontitis-associated species paralleling more signs of periodontitis in established AAV-patients than controls. Saliva microbiota in acute-AAV showed higher within-sample diversity but fewer detectable amplicon-sequence variants and taxa in their core microbiota than controls. Acute-AAV was not associated with increased abundance of periodontal bacteria but species in, e.g., Arthrospira, Staphylococcus, Lactobacillus, and Scardovia. In conclusion, the IgG profiles against oral bacteria differed between pre-AAV, established AAV, and controls, and microbiota profiles between acute AAV and controls. The IgG shift from a pre-symptomatic stage to established disease cooccurred with treatment of immunosuppression and/or antibiotics.

Distinct Microbial Signatures between Periodontal Profile Classes

Precise classification of periodontal disease has been the objective of concerted efforts and has led to the introduction of new consensus-based and data-driven classifications. The purpose of this study was to characterize the microbiological signatures of a latent class analysis (LCA)-derived periodontal stratification system, the Periodontal Profile Class (PPC) taxonomy. We used demographic, microbial (subgingival biofilm composition), and immunological data (serum IgG antibody levels, obtained with checkerboard immunoblotting technique) for 1,450 adult participants of the Dental Atherosclerosis Risk in Communities (ARIC) study, with already generated PPC classifications. Analyses relied on t tests and generalized linear models with Bonferroni correction. Men and African Americans had higher systemic antibody levels against most microorganisms compared to women and Caucasians (P < 0.05). Healthy individuals (PPC-I) had low levels of biofilm bacteria and serum IgG levels against most periodontal pathogens (P < 0.05). Subjects with mild to moderate disease (PPC-II to PPC-III) showed mild/moderate colonization of multiple biofilm pathogens. Individuals with severe disease (PPC-IV) had moderate/high levels of biofilm pathogens and antibody levels for orange/red complexes. High gingival index individuals (PPC-V) showed moderate/high levels of biofilm Campylobacter rectus and Aggregatibacter actinomycetemcomitans. Biofilm composition in individuals with reduced periodontium (PPC-VI) was similar to health but showed moderate to high antibody responses. Those with severe tooth loss (PPC-VII) had significantly high levels of multiple biofilm pathogens, while the systemic antibody response to these microorganisms was comparable to health. The results support a biologic basis for elevated risk for periodontal disease in men and African Americans. Periodontally healthy individuals showed a low biofilm pathogen and low systemic antibody burden. In the presence of PPC disease, a microbial-host imbalance characterized by higher microbial biofilm colonization and/or systemic IgG responses was identified. These results support the notion that subgroups identified by the PPC system present distinct microbial profiles and may be useful in designing future precise biological treatment interventions.

Exposure to Porphyromonas gingivalis and Modifiable Risk Factors Modulate Risk for Early Diabetic Retinopathy

Purpose

We hypothesized that exposure to Porphyromonas gingivalis (Pg) increases the risk for early diabetic retinopathy (DR) and that the risk can be modulated.

Methods

We identified 116 early DR cases, and 116 non-DR controls were selected randomly by frequency matching for age, sex, race, and education from the US Third National Health and Nutrition Examination Survey. DR was assessed using non-mydriatic fundus photographs and graded by trained graders using the Modified Airlie House Classification scheme and the Early Treatment for Diabetic Retinopathy Study severity scale. Serum Pg immunoglobulin G (IgG) antibody (Ab) was measured in enzyme-linked immunosorbent assay units. Logistic regression was used to relate serum Pg IgG Ab levels to the risk for early DR.

Results

Per tenfold increase in Pg IgG Ab levels, there was an over 60% increased risk for early DR (odds ratio = 1.64; 95% confidence interval, 1.36–1.97), and a linear trend was noted for the estimated probabilities of early DR at various Pg IgG Ab levels (P for trend = 0.0053). The analysis also suggested that moderate alcohol consumption (less than 12 drinks in the past 12 months; P for interaction = 0.0003) and maintaining a normal serum glycated hemoglobulin level (HbA1c ≤ 5.7%; P for interaction < 0.0001) helped reduce the Pg-related DR risk.

Conclusions

The increased Pg-related DR risk could be alleviated by managing alcohol consumption and maintaining a normal blood glucose level.

Translational Relevance

Findings from this study provide new directions for developing novel therapeutics and prevention strategies for DR.

Heritability of Oral Microbiota and Immune Responses to Oral Bacteria

Maintaining a symbiotic oral microbiota is essential for oral and dental health, and host genetic factors may affect the composition or function of the oral microbiota through a range of possible mechanisms, including immune pathways. The study included 836 Swedish twins divided into separate groups of adolescents (n = 418) and unrelated adults (n = 418). Oral microbiota composition and functions of non-enzymatically lysed oral bacteria samples were evaluated using 16S rRNA gene sequencing and functional bioinformatics tools in the adolescents. Adaptive immune responses were assessed by testing for serum IgG antibodies against a panel of common oral bacteria in adults. In the adolescents, host genetic factors were associated with both the detection and abundance of microbial species, but with considerable variation between species. Host genetic factors were associated with predicted microbiota functions, including several functions related to bacterial sucrose, fructose, and carbohydrate metabolism. In adults, genetic factors were associated with serum antibodies against oral bacteria. In conclusion, host genetic factors affect the composition of the oral microbiota at a species level, and host-governed adaptive immune responses, and also affect the concerted functions of the oral microbiota as a whole. This may help explain why some people are genetically predisposed to the major dental diseases of caries and periodontitis.

43-Year Temporal Trends in Immune Response to Oral Bacteria in a Swedish Population

Bacteria colonizing the mouth induce an adaptive immune response with the systemic and local presence of species or strain-specific immunoglobulins. Few studies have addressed global antibody patterns for oral bacteria or potential population time trends. We assessed these aspects in relation to a panel of oral bacteria. Using multiplex immunoblotting, IgG levels for 26 oral bacterial species (54 strains) were determined in 888 plasma samples from 30-year-old early pregnant women (n = 516) and 50-year-old men and women (n = 372) collected between 1976 and 2018. Inter-species correlations were found and age-dependent profiles and levels of immune responses to oral bacteria confirmed. We found temporal trends in the global and single-species antibody responses, but this was age-specific with both inclining and declining shifts. Prominent shifts in the younger group increased IgG towards health-associated Streptococcus salivarius and Streptococcus sanguinis, and in the older group towards disease-associated Aggregatibacter actinomycetemcomitans, Filifactor alocis, and Streptococcus mutans, among others. We concluded that temporal shifts occurred from 1976 to 2018, which may reflect improved oral health (more remaining teeth) and altered lifestyle habits, but this needs to be evaluated in observational studies considering more aspects.

Soluble urokinase-type plasminogen activator receptor is associated with signs of periodontitis in adolescents

Owing to its molecular stability in body fluids, soluble urokinase-type plasminogen activator receptor (suPAR) is used as a biomarker for the level of systemic inflammation. This study compares the suPAR levels in serum with those in the saliva of adolescents and evaluates their association with the periodontal conditions. Adolescents identified as screen positive (n = 87) or screen negative (n = 73) for periodontitis had saliva and serum samples taken, along with subgingival plaque samples. The concentrations of suPAR were determined in saliva and serum, and 18 microbial species and the immunoglobulin response to them was evaluated. Factor analyses were used to reduce the number of variables within each of the domains of clinical, microbiological, and immunological findings. The median salivary suPAR concentration was 13.18 [(interquartile range (IQR): 6.20-23.36] μg l^-1 and was not associated with the serum suPAR levels (median 2.05; IQR: 1.62-2.46 μg l^-1 ). Linear regression analysis showed that the log₁₀ (salivary suPAR concentration) was statistically significantly positively associated with the clinical phenotype 'Periodontitis Extent' (β = 0.28; 95% CI: 0.16-0.39) along with 'Putative periodontopathogens' (β = 0.65; 95% CI: 0.51-0.79). The study represents the first determination of salivary suPAR concentration in a larger well-defined adolescent population. Our results suggest the potential for clinical use of suPAR in saliva as an inflammatory risk indicator/biomarker of periodontitis.

Associations between Periodontal Microbiota and Death Rates

It is conceived that specific combinations of periodontal bacteria are associated with risk for the various forms of periodontitis. We hypothesized that such specificity is also related to human cause-specific death rates. We tested this hypothesis in a representative sample of the US population followed for a mean duration of 11 years and found that two specific patterns of 21 serum antibodies against periodontal bacteria were significantly associated with increased all-cause and/or diabetes-related mortalities. These data suggested that specific combinations of periodontal bacteria, even without inducing clinically significant periodontitis, may have a significant impact on human cause-specific death rates. Our findings implied that increased disease and mortality risk could be transmittable via the transfer of oral microbiota, and that developing personalized strategies and maintaining healthy oral microbiota beyond protection against periodontitis would be important to manage the risk.

Oxidative Stress and IgG Antibody Modify Periodontitis-CRP Association

In a previous report, we demonstrated the inverse association of high serum 8-isoprostane levels, a marker for oxidative stress, with decreased serum IgG antibodies to oral bacteria. The association between increased serum IgG with increased plaque and periodontitis (increased probing depths) was attenuated by high systemic oxidative stress. Other investigations have reported a role for systemic oxidative stress as a stimulus of hepatic C-reactive protein (CRP) response. These observations led us to hypothesize that the reported relationship of periodontitis to elevated serum CRP, a systemic inflammatory marker, may be modified by oxidative stress and that the levels of serum antibodies to oral bacteria might be an intermediary explanatory variable linking the association of systemic oxidative stress, periodontal disease, and levels of CRP. This hypothesis was explored as a secondary analysis of the Dental ARIC (Atherosclerosis Risk in Communities) study using serum levels of CRP, serum IgG levels to 16 oral organisms, serum levels of 8-isoprostane, and periodontal status. The findings indicate periodontitis is associated with high CRP in the presence of elevated oxidative stress that serves to suppress the IgG response. Only within the highest 8-isoprostane quartile was periodontitis (pocket depth) associated with increased serum CRP levels (P = 0.0003). Increased serum IgG antibody levels to oral bacteria were associated with lowered serum CRP levels. Thus, systemic oxidative stress, which has been demonstrated to be associated with increased levels of CRP in other studies, appears to be associated with the suppression of bacterial-specific IgG levels, which in the presence of periodontal disease can result in an enhanced systemic CRP response. Conversely, individuals with increased serum IgG antibodies to plaque bacteria exhibit lowered serum CRP levels. These 2 factors, oxidative stress and the serum IgG response, appear to function in opposing directions to modify serum levels of CRP and the association with periodontitis.

Serum IgG antibody levels to periodontal microbiota are associated with incident Alzheimer disease

Background

Periodontitis and Alzheimer disease (AD) are associated with systemic inflammation. This research studied serum IgG to periodontal microbiota as possible predictors of incident AD.

Methods

Using a case-cohort study design, 219 subjects (110 incident AD cases and 109 controls without incident cognitive impairment at last follow-up), matched on race-ethnicity, were drawn from the Washington Heights-Inwood Columbia Aging Project (WHICAP), a cohort of longitudinally followed northern Manhattan residents aged >65 years. Mean follow-up was five years (SD 2.6). In baseline sera, serum IgG levels were determined for bacteria known to be positively or negatively associated with periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Actinobacillus actinomycetemcomitans Y4, Treponema denticola, Campylobacter rectus, Eubacterium nodatum, and Actinomyces naeslundii genospecies-2). In all analyses, we used antibody threshold levels shown to correlate with presence of moderate-severe periodontitis.

Results

Mean age was 72 years (SD 6.9) for controls, and 79 years (SD 4.6) for cases (p<0.001). Non-Hispanic Whites comprised 26%, non-Hispanic Blacks 27%, and Hispanics 48% of the sample. In a model adjusting for baseline age, sex, education, diabetes mellitus, hypertension, smoking, prior history of stroke, and apolipoprotein E genotype, high anti-A. naeslundii titer (>640 ng/ml, present in 10% of subjects) was associated with increased risk of AD (HR = 2.0, 95%CI: 1.1–3.8). This association was stronger after adjusting for other significant titers (HR = 3.1, 95%CI: 1.5–6.4). In this model, high anti-E. nodatum IgG (>1755 ng/ml; 19% of subjects) was associated with lower risk of AD (HR = 0.5, 95%CI: 0.2–0.9).

Conclusions

Serum IgG levels to common periodontal microbiota are associated with risk for developing incident AD.

Plasma antibodies to oral bacteria and risk of pancreatic cancer in a large European prospective cohort study

OBJECTIVE

Examine the relationship between antibodies to 25 oral bacteria and pancreatic cancer risk in a prospective cohort study.

DESIGN

We measured antibodies to oral bacteria in prediagnosis blood samples from 405 pancreatic cancer cases and 416 matched controls, nested within the European Prospective Investigation into Cancer and Nutrition study. Analyses were conducted using conditional logistic regression and additionally adjusted for smoking status and body mass index.

RESULTS

Individuals with high levels of antibodies against Porphyromonas gingivalis ATTC 53978, a pathogenic periodontal bacteria, had a twofold higher risk of pancreatic cancer than individuals with lower levels of these antibodies (OR 2.14; 95% CI 1.05 to 4.36; >200 ng/ml vs ≤200 ng/ml). To explore the association with commensal (non-pathogenic) oral bacteria, we performed a cluster analysis and identified two groups of individuals, based on their antibody profiles. A cluster with overall higher levels of antibodies had a 45% lower risk of pancreatic cancer than a cluster with overall lower levels of antibodies (OR 0.55; 95% CI 0.36 to 0.83).

CONCLUSIONS

Periodontal disease might increase the risk for pancreatic cancer. Moreover, increased levels of antibodies against specific commensal oral bacteria, which can inhibit growth of pathogenic bacteria, might reduce the risk of pancreatic cancer. Studies are needed to determine whether oral bacteria have direct effects on pancreatic cancer pathogenesis or serve as markers of the immune response.

Lifestyle, dietary factors, and antibody levels to oral bacteria in cancer-free participants of a European cohort study

BACKGROUND

Increasing evidence suggests that oral microbiota play a pivotal role in chronic diseases, in addition to the well-established role in periodontal disease. Moreover, recent studies suggest that oral bacteria may also be involved in carcinogenesis; periodontal disease has been linked to several cancers. In this study, we examined whether lifestyle factors have an impact on antibody levels to oral bacteria.

METHODS

Data on demographic characteristics, lifestyle factors, and medical conditions were obtained at the time of blood sample collection. For the current analysis, we measured antibody levels to 25 oral bacteria in 395 cancer-free individuals using an immunoblot array. Combined total immunoglobin G (IgG) levels were obtained by summing concentrations for all oral bacteria measured.

RESULTS

IgG antibody levels were substantially lower among current and former smokers (1,697 and 1,677 ng/mL, respectively) than never smokers (1,960 ng/mL; p trend = 0.01), but did not vary by other factors, including body mass index, diabetes, physical activity, or by dietary factors, after adjusting for age, sex, education, country, and smoking status. The highest levels of total IgG were found among individuals with low education (2,419 ng/mL).

CONCLUSIONS

Our findings on smoking are consistent with previous studies and support the notion that smokers have a compromised humoral immune response. Moreover, other major factors known to be associated with inflammatory markers, including obesity, were not associated with antibody levels to a large number of oral bacteria.

Mechanisms involved in the association between periodontal diseases and cardiovascular disease

It is now well accepted that besides the cholesterol associated mechanisms of atherogenesis, inflammation plays a crucial role in all stages of the development of the atherosclerotic lesion. This 'inflammation hypothesis' raises the possibility that through systemic elevations of pro-inflammatory cytokines, periodontal diseases might also contribute to systemic inflammation and, therefore, to atherogenesis. In fact, there is evidence that periodontal diseases are associated with higher systemic levels of high-sensitivity C-reactive protein and a low grade systemic inflammation. This phenomenon has been explained based on mechanisms associated with either the infectious or the inflammatory nature of periodontal diseases. The purposes of this article were to review (1) the evidence suggesting a role for oral bacterial species, particularly periodontal pathogens, in atherogenesis; (2) the potential mechanisms explaining an etiological role for oral bacteria in atherosclerosis; (3) the evidence suggesting that periodontal infections are accompanied by a heightened state of systemic inflammation; (4) the potential sources of systemic inflammatory biomarkers associated with periodontal diseases; and (5) the effects of periodontal therapy on systemic inflammatory biomarkers and cardiovascular risk.

Periodontal pathogen carriage, rather than periodontitis, determines the serum antibody levels

AIM

We investigated in a nationally representative sample, how periodontitis modifies the association between the carriage of periodontal pathogens and serology.

MATERIALS AND METHODS

The population comprised 1586 dentate subjects who participated in an interview, clinical and radiological oral health examination, and saliva collection. Serum immunoglobulin A (IgA)- and IgG-class antibody levels against Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis and their salivary occurrence were determined in the whole population. The quantity of the pathogens was measured in a subpopulation.

RESULTS

In the univariate analyses, the corresponding antibody levels were higher in the pathogen carriers compared with the non-carriers, and clearly higher in the carriers with periodontal pockets compared with the carriers without. In the multi-variate analyses, however, all antibody levels associated strongly with age (p<0.001) and the carriage of the corresponding pathogen (p<0.001), but only weakly with the presence or number of teeth with periodontal pockets. In the subpopulation, the antibody levels and the numbers of corresponding bacteria in saliva had a positive association, which was not affected by the disease.

CONCLUSIONS

The carriage of A. actinomycetemcomitans and P. gingivalis is the strongest determinant of the systemic antibody response to these pathogens, and the extent of periodontitis has at most a modest modifying effect.

Determinants of serum IgG responses to periodontal bacteria in a nationally representative sample of US adults

AIM

To assess the distribution of elevated antibody titres to multiple periodontal bacteria, including established/putative pathogens and health-related species, by selected demographic, behavioural, and oral- and general health-related characteristics.

METHODS

Data from 8153 >or=40-year-old participants from the third National Health and Nutrition Examination Survey were used, including 1588 edentulous individuals. We used checkerboard immunoblotting to assess serum IgG levels to 19 periodontal species. Thresholds for elevated antibody responses were defined for each species using the 90th percentile titre in periodontal healthy participants, using two alternative definitions of periodontitis.

RESULTS

Edentulous individuals showed lower antibody responses than dentate participants, notably for titres to "red complex" species and Actinobacillus actinomycetemcomitans. Elevated titres to Porphyromonas gingivalis were twice as prevalent in participants with periodontitis than in periodontal healthy individuals. Non-Hispanic blacks and Mexican-Americans were more likely to display elevated titres for P. gingivalis compared with non-Hispanic whites (22.9%versus 19.4%versus 9.5%). Current smokers were significantly less likely to exhibit high titres to multiple bacteria than never smokers.

CONCLUSION

Demographic, behavioural, and oral- and general health-related characteristics were strong determinants of systemic antibody responses to periodontal bacteria in a nationally representative sample of US adults.

Association of systemic oxidative stress with suppressed serum IgG to commensal oral biofilm and modulation by periodontal infection

To assess the impact of systemic oxidative stress on humoral immune responses, we examined the relation between levels of serum 8-isoprostane and serum IgG antibodies against 17 microorganisms in the commensal oral biofilm among the ARIC population of community-dwelling adults (n = 4,717). Bivariately, serum 8-isoprostane was associated with age, race/center, education, smoking, serum triglycerides, and the extent of periodontal disease severity. Total IgG antibody directed to the oral biofilm was significantly associated with race/center, hypertension, triglycerides, periodontal disease severity, plaque, and serum 8-isoprostane. In multivariate models, the highest quartile of increased 8-isoprostane displayed marked reductions (44%) in biofilm IgG antibody in contrast to small increases in total IgG antibody level for the highest quartiles of oral bacterial burden or periodontal disease severity (19 and 12%, respectively; p < 0.0001). Increased 8-isoprostane was associated with decreased total IgG antibody (p < 0.0001) in subjects with or without extensive periodontal disease and/or biofilm and with suppression of IgG responses across the entire biofilm composition. Increased systemic oxidative stress is associated with a generalized decrease of serum IgG antibody responses to the oral biofilm. Levels of oral microbial burden, periodontitis severity, and smoking are, by comparison, minor modifiers of serum IgG responses to the commensal oral biofilm.

Application of the checkerboard immunoblotting technique to the quantification of host biomarkers in gingival crevicular fluid

BACKGROUND

The aim of this study was to describe the development and validation of the checkerboard immunoblotting (CBIB) technique for the high-throughput quantification of multiple inflammatory mediators in gingival crevicular fluid (GCF) samples.

METHODS

Monoclonal antibodies were used to bind GCF interleukin (IL)-1beta and -8 and matrix metalloproteinase (MMP)-8 to the surface of membranes. Biotinylated antibodies were used to detect bound antigens in a checkerboard format. Signals were developed using chemiluminescence, captured on film, and quantified using software for array analysis. The assay was tested for potential cross-reactions among the three pairs of antibodies. Eleven CBIBs were processed to determine the analytical sensitivity of the assay. Forty GCF samples were analyzed using CBIB and enzyme-linked immunosorbent assay (ELISA) in parallel, and the significance of the correlations among the results was tested using the Pearson correlation coefficient. Nine hundred thirty-one GCF samples were collected from 20 periodontally healthy subjects and 20 periodontitis subjects and analyzed using CBIB to test the assay's sensitivity and dynamic ranges using clinical samples.

RESULTS

The CBIB was capable of distinguishing among the three analytes. The sensitivity and dynamic ranges of the assay were suitable for the detection of the three targets in the majority of GCF samples. There were highly statistically significant (P <0.0001) positive correlations between CBIB and ELISA data for all three biomarkers. The periodontitis subjects had statistically significantly higher mean levels of IL-1beta and -8 compared to healthy subjects.

CONCLUSION

The CBIB technique is a sensitive and specific assay for the high-throughput quantification of MMP-8 and IL-8 and -1beta in GCF.

Heterogeneity of systemic inflammatory responses to periodontal therapy

AIMS

We investigated the effect of comprehensive periodontal therapy on the levels of multiple systemic inflammatory biomarkers.

MATERIAL AND METHODS

Thirty patients with severe periodontitis received comprehensive periodontal therapy within a 6-week period. Blood samples were obtained at: 1-week pre-therapy (T1), therapy initiation (T2), treatment completion (T3), and 4 weeks thereafter (T4). We assessed the plasma concentrations of 19 biomarkers using multiplex assays, and serum IgG antibodies to periodontal bacteria using checkerboard immunoblotting. At T2 and T4, dental plaque samples were analysed using checkerboard hybridizations.

RESULTS

At T3, PAI-1, sE-selectin, sVCAM-1, MMP-9, myeloperoxidase, and a composite summary inflammatory score (SIS) were significantly reduced. However, only sE-selectin, sICAM, and serum amyloid P sustained a reduction at T4. Responses were highly variable: analyses of SIS slopes between baseline and T4 showed that approximately 1/3 and 1/4 of the patients experienced a marked reduction and a pronounced increase in systemic inflammation, respectively, while the remainder were seemingly unchanged. Changes in inflammatory markers correlated poorly with clinical, microbiological and serological markers of periodontitis.

CONCLUSIONS

Periodontal therapy resulted in an overall reduction of systemic inflammation, but the responses were inconsistent across subjects and largely not sustainable. The determinants of this substantial heterogeneity need to be explored further.

Identification of Tannerella forsythia antigens specifically expressed in patients with periodontal disease

Molecular pathogenesis of Tannerella forsythia, a putative periodontal pathogen, has not yet been adequately elucidated due to limited information on its virulence factors. Here, identification of in vivo expressed antigens of T. forsythia is reported using in vivo-induced antigen technology (IVIAT). Among 13 000 recombinant clones screened, 16 positive clones were identified that reacted reproducibly with sera obtained from patients with periodontal disease. DNA sequences from 12 of these in vivo-induced genes were determined. IVIAT-identified protein antigens of T. forsythia include: BspA, a well-defined virulence factor of T. forsythia; enzymes involved in housekeeping functions (tRNA synthetases, glycine hydroxymethyltransferase, and glucoside glucohydrolase); enzymes implicated in tissue destruction (dipeptidyl peptidase IV); a DNA mismatch repair protein; and putative outer membrane proteins of unknown function. The in vivo gene expression of these IVIAT-identified antigens was confirmed by a quantitative real-time PCR analysis. This is, to the best of the authors' knowledge, the first report using IVIAT in T. forsythia. It is anticipated that detailed analysis of the in vivo-induced genes identified by IVIAT in this study will lead to a better understanding of the molecular mechanisms mediating periodontal infection by T. forsythia.

Persistently high levels of periodontal pathogens associated with preterm pregnancy outcome

BACKGROUND

Few studies examining the association between periodontal diseases and preterm birth have explored the underlying microbial and antibody responses associated with oral infection.

METHODS

A nested case-control study was performed using data from a recent interventional trial following the delayed-treatment control group of 31 subjects with periodontal diseases. The levels of eight oral bacteria and the maternal immunoglobulin G (IgG) responses in serum to these bacteria were measured at antepartum and postpartum visits to determine the relationship to cases (preterm delivery <37 weeks' gestation) and controls (term delivery).

RESULTS

Antepartum, the levels of periodontal pathogens tended to be higher in the preterm (case group) deliveries compared to the term deliveries (control group). Maternal anti-Porphyromonas gingivalis IgG was significantly lower in the preterm group compared to the term group (P = 0.028). Postpartum, levels of P. gingivalis, Tannerella forsythia, Prevotella intermedia, and Prevotella nigrescens were statistically significantly higher in preterm births compared to term deliveries, adjusting for baseline levels. The joint effects of red and orange microbial clusters were significantly higher in the preterm group compared to the term group.

CONCLUSIONS

High levels of periodontal pathogens and low maternal IgG antibody response to periodontal bacteria during pregnancy are associated with an increased risk for preterm delivery. Further studies elucidating the role of the microbial load and maternal immune response as related to pregnancy outcome seem merited.

Effects of periodontal therapy on serum C-reactive protein, sE-selectin, and tumor necrosis factor-? secretion by peripheral blood-derived macrophages in diabetes. A pilot study

BACKGROUND AND OBJECTIVE

Diabetes is associated with an increased risk for vascular disease and periodontitis. The aim of this study was to assess the effects of periodontal treatment in diabetes with respect to alterations in the pro-inflammatory potential of peripheral blood mononuclear cells.

MATERIAL AND METHODS

Ten patients with diabetes and moderate to severe periodontitis received full-mouth subgingival debridement. Blood samples for serum/plasma and mononuclear cell isolation were collected prior to and 4 wk after therapy. Mononuclear cells were analyzed by flow cytometry and stimulated with lipopolysaccharide or ionomycin/phorbol ester to determine the pro-inflammatory capacity of macrophages and lymphocytes, respectively.

RESULTS

Following periodontal treatment, all patients demonstrated a significant improvement in clinical periodontal status (p < 0.05), despite only modest reduction in subgingival bacterial load or homologous serum immunoglobulin G titers. CD14(+) blood monocytes decreased by 47% (p < 0.05), and the percentage of macrophages spontaneously releasing tumor necrosis factor-alpha decreased by 78% (p < 0.05). There were no significant changes in the capacity of lymphocytes to secrete interferon-gamma. Among a number of serum inflammatory markers tested, high-sensitivity-C-reactive protein significantly decreased by 37% (p < 0.01) and soluble E-selectin decreased by 16.6% (p < 0.05).

CONCLUSION

These data suggest a reduced tendency for monocyte/macrophage-driven inflammation with periodontal therapy and a potential impact on atherosclerosis-related complications in diabetic individuals.

Periodontal infection profiles in type 1 diabetes

OBJECTIVES

We investigated the levels of subgingival plaque bacteria and serum IgG responses in patients with type 1 diabetes and non-diabetic controls of comparable periodontal status.

MATERIAL AND METHODS

Fifty type 1 diabetes patients (mean duration 20.3 years, range 6-41) were age-and gender-matched with 50 non-diabetic individuals with similar levels of periodontal disease. Full-mouth clinical periodontal status was recorded, and eight plaque samples/person were collected and analysed by checkerboard hybridization with respect to 12 species. Homologous serum IgG titres were assessed by checkerboard immunoblotting. In a sub-sample of pairs, serum cytokines and selected markers of cardiovascular risk were assessed using multiplex technology.

RESULTS

Among the investigated species, only levels of Eubacterium nodatum were found to be higher in diabetic patients, while none of the IgG titres differed between the groups, both before and after adjustments for microbial load. Patients with diabetes had significantly higher serum levels of soluble E-selectin (p=0.04), vascular cell adhesion molecule-1 (VCAM-1; p=0.0008), adiponectin (p=0.01) and lower levels of plasminogen activator inhibitor-1 (PAI-1; p=0.02).

CONCLUSIONS

After controlling for the severity of periodontal disease, patients with type 1 diabetes and non-diabetic controls showed comparable subgingival infection patterns and serum antibody responses.

Fcgamma receptor polymorphisms and periodontal status: a prospective follow-up study

AIMS

The aims of this study were to assess: (i) the distribution of Fcgamma receptor polymorphisms among patients with chronic periodontitis ("cases") and control subjects with no/minimal loss of periodontal tissue support in a Caucasian population; (ii) whether these polymorphisms can serve as severity markers for periodontitis; and (iii) whether they have any bearing on the response to periodontal therapy.

METHODS

The study sample consisted of 132 cases and 73 controls of comparable age and gender. Full-mouth periodontal status was assessed. Subgingival plaque (PL) samples and blood samples were obtained and analysed with respect to 19 bacterial species and homologous serum immunoglobulin G titres. Polymorphisms in the Fcgamma receptor IIa (131R/H) and IIIb (NA1/NA2) were assessed by polymerase chain reaction. Patients underwent periodontal therapy and were followed up at 4 and 30 months.

RESULTS

Neither polymorphism showed a skewed distribution among cases and controls. At baseline, periodontitis patients with Fcgamma RIIa-H/H131 genotype had more PL and deeper pockets than patients in other genotype groups (p < 0.05). Both bacterial levels and antibody titres were unrelated to genotype. The longitudinal analysis failed to detect an association between genotype and response to periodontal therapy.

CONCLUSIONS

The present data failed to demonstrate a clinically relevant relationship between the Fcgamma receptor IIa (131R/H) or IIIb (NA1/NA2) polymorphism and periodontal status.

Antepartum vaginal bleeding, fetal exposure to oral pathogens, and risk for preterm birth at <35 weeks of gestation

OBJECTIVE

The purpose of this study was to determine the risks for fetal exposure to oral pathogens and the relationship between vaginal bleeding and fetal exposure in preterm birth risk.

STUDY DESIGN

An analysis of prospectively collected data for the longitudinal Oral Conditions and Pregnancy Study was conducted. Maternal factors that potentially were associated with fetal exposure to oral pathogens (defined as detection of umbilical cord serum Immunoglobulin M to 1 of 5 oral pathogens) were examined, and the role of vaginal bleeding and fetal exposure to oral pathogens in preterm birth risk was explored. Preterm birth was defined as delivery at <35 weeks of gestation. An adjusted relative risk (95% CI) for fetal exposure was calculated. Adjusted hazard ratios (95% CI) were calculated for preterm birth among women whose data were stratified by the presence/absence of bleeding and/or fetal exposure to oral pathogens.

RESULTS

There were complete data for 661 women; 230 women (34.8%) with and 431 women (65.2%) without fetal exposure to oral pathogens. In multivariable analysis, first- or second-trimester bleeding and white race were associated significantly with fetal exposure to oral pathogens (adjusted relative risk, 1.8 [95% CI, 1.3-2.5] and 1.3 [95% CI, 1.1-1.7], respectively). The adjusted hazard ratio for preterm birth among women with first- or second-trimester bleeding and fetal exposure to oral pathogens was 6.4 (95% CI: 2.6-16.0).

CONCLUSION

Vaginal bleeding is associated with fetal exposure to oral pathogens, which increases preterm birth risk. Whether bleeding is the cause of or result of fetal exposure to oral pathogens remains to be determined.

Systemic effects of periodontitis: epidemiology of periodontal disease and cardiovascular disease

There have been 42 published studies describing associations between oral conditions and cardiovascular diseases. In the absence of randomized controlled trials, the 16 longitudinal studies represent the highest level of evidence available. However, two databases produced eight of the 16 studies. There also is extensive variability in definitions of the oral exposure that include salivary flow, reported periodontal disease, number of teeth, oral organisms, antibodies to oral organisms, Total Dental Index, Community Periodontal Index of Treatment Needs, plaque scores, probing depth, attachment loss, and bone level. Variability also exists in the cardiovascular outcomes that include atherosclerosis measures and events, such as hospitalization for coronary heart disease (CHD), chronic CHD, fatal CHD, total stroke, ischemic stroke, and revascularization procedures. One of the criticisms of this research is that the exposure has not been represented by measures of infection. To begin to address this concern, we present new data showing that patterns of high and low levels of eight periodontal pathogens and antibody levels against those organisms are related to clinical periodontal disease as well as other characteristics of the individuals, such as age, race, gender, diabetic status, atherosclerosis, and CHD. As others before us, we conclude that the cumulative evidence presented above supports, but does not prove, a causal association between periodontal infection and atherosclerotic cardiovascular disease or its sequelae. A number of legitimate concerns have arisen about the nature of the relationship and, indeed, the appropriate definitions for periodontal disease when it is thought to be an exposure for systemic diseases. There is still much work needed to identify which aspects of the exposure are related to which aspects of the outcome. Principal component analyses illustrate the complexity of the interactions among risk factors, exposures, and outcomes. These analyses provide an initial clustering that describes and suggests the presence of specific syndromes.

Infection patterns in chronic and aggressive periodontitis

BACKGROUND

We revisited the postulate that localized aggressive periodontitis (LAP) patients have robust serum antibody (ab) responses to periodontal pathogens while patients with generalized aggressive periodontitis (GAP) show weak responses. We also studied ab responses in localized chronic (LCP) and generalized chronic periodontitis (GCP).

METHODS

Fifty-seven patients (14-74 years, 25% male, 70% Hispanic, 26% African American) were studied (15 LAP, 19 GAP, 11 LCP, 12 GCP patients). Three plaque samples/subject were analysed with respect to 15 species, and serum immunoglobulin G (IgG) responses to the same bacteria were determined. Ab responses were expressed as log-transformed titres, and "infection ratios", i.e., log-transformed ratios of ab titre over the subject-based mean bacterial load for the homologous species.

RESULTS

The results failed to corroborate the postulate that LAG patients have robust responses to infecting agents while GAP subjects exhibit weak responses. This held true for ab to "red complex", "orange complex", and health-associated species, and for both titres and infection ratios. Similarly, no differences were found between ab titres or infection ratios in chronic and aggressive periodontitis, or their extent-based subdivisions.

CONCLUSIONS

A distinction between the two principal categories of the current periodontitis classification cannot be established by the study of infection patterns.

Fetal immune response to oral pathogens and risk of preterm birth

OBJECTIVE

The purpose of this study was to determine the relationship between fetal inflammatory and immune responses to oral pathogens and risk for preterm birth.

STUDY DESIGN

Six hundred and forty umbilical cord blood specimens were prospectively collected. Cord serum levels of C-reactive protein, interleukin (IL)-1beta, IL-6, tumor necrosis factor (TNF)-alpha, Prostaglandin E2, and 8-isoprostane were determined by enzyme-linked immunosorbent assay and categorized as > median (high) versus < or = median (low). Presence of fetal immunoglobulin M (IgM) antibody against oral pathogens was determined by checkerboard immunoblot assay; detection of > or = 1 oral pathogen specific antibody was categorized as positive. Preterm birth was defined as spontaneous delivery at <35 weeks. Chi-square analysis was used to determine association between cord serum mediator or IgM category and preterm birth. Odds ratios (OR) for preterm birth were calculated, stratified by mediator and IgM category.

RESULTS

Of 640 births, 48 (7.5%) delivered preterm. Preterm birth rates were higher if categorized as high versus low 8-isoprostane or TNF-alpha (23 vs 5%, P < .001 and 10 vs 4%, P < .01, respectively). Preterm birth rates were also higher if categorized as IgM positive versus negative (10.6 vs 5.8%, P = .04). The joint effects of fetal IgM seropositivity, detectable C-reactive protein, or high 8-isoprostane, PGE(2), or TNF-alpha resulted in significantly increased risk for preterm birth (adjusted OR [95% CI]: 6.0 [2.2-16.5], 4.3 [1.6-11.5], 4.1 [1.5-11.6], and 7.6 [2.3-20.8], respectively).

CONCLUSION

Fetal exposure to oral pathogens evidenced by an IgM response is associated with preterm birth, and the risk for preterm birth is greatest among fetuses that also demonstrate an inflammatory response.

Periodontal disease and coronary heart disease: a reappraisal of the exposure

BACKGROUND

Results from studies relating periodontal disease to cardiovascular disease have been mixed. Residual confounding by smoking and use of clinical measures of periodontal disease rather than measures of infection have been 2 major criticisms. The aims of this study were to investigate relationships between prevalent coronary heart disease (CHD) and 2 exposures, (1) clinical periodontal disease and (2) IgG antibodies to 17 oral organisms, and to evaluate the role of smoking in these relationships.

METHODS AND RESULTS

Our study is based on a subset of participants in the Atherosclerosis Risk in Communities (ARIC) Study, who received a complete periodontal examination during visit 4 (1996-1998). The exposures were periodontal status and serum IgG antibody levels against 17 periodontal organisms, and the outcome was prevalent CHD at visit 4. Multivariable analyses indicate that periodontal status is not significantly associated with CHD in either ever smokers or never smokers. Similar analyses evaluating antibodies indicate that high antibodies (above the median) to Treponema denticola (odds ratio [OR]=1.7; 95% CI, 1.2 to 2.3), Prevotella intermedia (OR=1.5; 95% CI, 1.1 to 2.0), Capnocytophaga ochracea (OR=1.5; 95% CI, 1.1 to 2.1), and Veillonella parvula (OR=1.7; 95% CI, 1.2 to 2.3) are significantly associated with CHD among ever smokers, whereas Prevotella nigrescens (OR=1.7; 95% CI, 1.1 to 2.6), Actinobacillus actinomycetemcomitans (OR=1.7; 95% CI, 1.2 to 2.7), and Capnocytophaga ochracea (OR=2.0; 95% CI, 1.3 to 3.0) were associated with CHD among never smokers.

CONCLUSIONS

Clinical signs of periodontal disease were not associated with CHD, whereas systemic antibody response was associated with CHD in ever smokers and never smokers. These findings indicate that the quality and quantity of the host response to oral bacteria may be an exposure more relevant to systemic atherothrombotic coronary events than clinical measures.

Markers of periodontal infection and preterm birth

OBJECTIVE

This study was undertaken to explore the relationship between clinical, microbiologic, and serologic markers of periodontitis and preterm birth (PTB).

STUDY DESIGN

We compared women with a singleton gestation giving birth before the 37th week (cases, n = 83) with term delivery controls (n = 120). Periodontal examination and collection of dental plaque and blood samples were performed within 48 hours after delivery. Microbial levels and maternal immunoglobulin G titers to oral bacteria were analyzed. Multivariate regression models were fitted controlling for common covariates.

RESULTS

Cases showed greater mean attachment loss (1.7 vs 1.5 mm, P = .003) and higher prevalence of periodontitis (30.1% vs 17.5%, P = .027). No differences in microbial or serum antibody levels were detected between the groups. Logistic regression revealed that PTB was associated with attachment loss (adjusted odds ratio: 2.75, 95% CI: 1.01-7.54). Linear regression indicated a significant ( P = .04) association between attachment loss and low birth weight (LBW).

CONCLUSION

The data support the notion that periodontitis is independently associated with PTB and LBW.

Chronic maternal and fetal Porphyromonas gingivalis exposure during pregnancy in rabbits

OBJECTIVE

This study was undertaken to develop a rabbit model of maternal exposure to Porphyromonas gingivalis and determine whether fetal or placental exposure occurs.

STUDY DESIGN

Subcutaneous steel chambers were implanted in 8 New Zealand White female rabbits. On day 7 of pregnancy, 4 rabbits were inoculated through the chamber with 5 x 10 8 CFU/mL live P gingivalis , and 4 rabbits with broth (controls) and sacrificed at term. Polymerase chain reaction was used to detect P gingivalis in maternal and fetal liver and placenta. Fisher exact test was used to compare P gingivalis detection between groups.

RESULTS

Among exposed does, P gingivalis was detected in 33% of the maternal livers, 49% of placentas, and 34% fetal livers compared with none from controls ( P < .001).

CONCLUSION

Chronic maternal exposure to P gingivalis results in systemic dissemination, transplacental passage, and fetal exposure. This model may be useful to study placental and fetal effects of this oral pathogen and to study microbial dissemination across the placenta.

Longitudinal stability of serum immunoglobulin G responses to periodontal bacteria

BACKGROUND

The value of seroepidemiology in the study of periodontal infections has not been adequately explored. This study examined serum immunoglobulin (IgG) responses to periodontal bacteria in patients with periodontitis and periodontitis-free individuals over a 30-month period.

METHODS

Eighty-nine patients with chronic periodontitis and 42 control subjects with no deep periodontal pockets and no or minimal attachment loss (30-72 years old, 43% men) were included. Patients were examined at baseline, after completed periodontal therapy 4 months post-baseline, and at 30 months, and controls, at baseline and 30 months. IgG antibodies to 19 periodontal species were determined by checkerboard immunoblotting.

RESULTS

On average, patients displayed at baseline up to 800-fold higher titers than controls to all but three species. Over the 30-month period, titers remained stable at low levels in controls. In patients, periodontal conditions improved from a baseline mean probing depth of 3.6 mm, bleeding on probing of 62% and an average of 21.5 pockets of=6 mm/person, to 2.5 mm mean pocket depth, 30% bleeding on probing, and 1.2 deep pockets, at 30 months. Over time, antibody titers showed a modest decline in patients, but remained significantly elevated at 30 months in comparison with controls. Antibody-level changes over time were not significantly different between subjects that did and did not receive adjunctive systemic antibiotics.

CONCLUSIONS

Conspicuous differences in IgG titers to periodontal bacteria exist between periodontitis patients and periodontally healthy controls. Despite successful periodontal therapy, titers remained elevated over a 30-month period, suggesting that serology may mark the history of past periodontal infection.

Gene expression signatures in chronic and aggressive periodontitis: a pilot study

This pilot study examined gene expression signatures in pathological gingival tissues of subjects with chronic or aggressive periodontitis, and explored whether new subclasses of periodontitis can be identified based on gene expression profiles. A total of 14 patients, seven with chronic and seven with aggressive periodontitis, were examined with respect to clinical periodontal status, composition of subgingival bacterial plaque assessed by checkerboard hybridizations, and levels of serum IgG antibodies to periodontal bacteria assayed by checkerboard immunoblotting. In addition, at least two pathological pockets/patient were biopsied, processed for RNA extraction, amplification and labeling, and used to study gene expression using Affymetrix U-133 A arrays. Based on a total of 35 microarrays, no significantly different gene expression profiles appeared to emerge between chronic and aggressive periodontitis. However, a de novo grouping of the 14 subjects into two fairly robust clusters was possible based on similarities in gene expression. These two groups had similar clinical periodontal status and subgingival bacterial profiles, but differed significantly with respect to serum IgG levels against the important periodontal pathogens Porphyromonas gingivalis, Tannerella forsythensis and Campylobacter rectus. These early data point to the usefulness of gene expression profiling techniques in the identification of subclasses of periodontitis with common pathobiology.

Porphyromonas gingivalis infection during pregnancy increases maternal tumor necrosis factor alpha, suppresses maternal interleukin-10, and enhances fetal growth restriction and resorption in mice

Epidemiological studies have shown a potential association between maternal periodontitis and pregnancy complications. We used a pregnant murine model to study the effect of infection with the periodontal pathogen Porphyromonas gingivalis on pregnancy outcomes. Female BALB/c mice were inoculated with heat-killed P. gingivalis (10(9) CFU) in a subcutaneous chamber and mated 2 weeks later. At gestation day (GD) 7.5, mice were challenged with live P. gingivalis (10(7) CFU) (n = 20) or broth (control; n = 8) and sacrificed at GD 16.5. Fetal growth restriction (FGR, <0.46 g) was defined as fetuses with weights 2 standard deviations (SD) smaller than controls (0.56 +/- 0.05 g [mean +/- SD]). Among the 20 challenged mice, 8 had both normal-weight (0.51 +/- 0.11 g) and FGR (0.34 +/- 0.1 g) fetuses within the same litter. All other challenged dams had normal-weight fetuses (0.57 +/- 0.04 g). Maternal liver, uterus, and spleen samples were examined for P. gingivalis DNA using a PCR technique. Of the eight challenged mice with FGR fetuses, three had PCR signals for P. gingivalis in liver and uterus, but not in the spleen. Liver, uterus, and spleen were negative for P. gingivalis DNA among all other challenged and control mice. In serum of dams with FGR fetuses, tumor necrosis factor alpha levels were elevated significantly, while interleukin-10 levels were significantly reduced compared to levels in dams with normal fetuses. P. gingivalis-specific serum immunoglobulin G levels were significantly elevated in dams with FGR fetuses compared to dams without any FGR fetuses. These data demonstrate that P. gingivalis-induced murine FGR is associated with systemic dissemination of the organism and activated maternal immune and inflammatory responses.

Oral infection with a periodontal pathogen accelerates early atherosclerosis in apolipoprotein E-null mice

OBJECTIVE

Because recent epidemiologic evidence suggests that periodontal infections may increase the risk of atherosclerosis and related events in humans, we assessed the impact of oral inoculation with the periodontal pathogen Porphyromonas gingivalis on atherogenesis in hypercholesterolemic apolipoprotein E-null mice.

METHODS AND RESULTS

In the absence of alterations in distinct risk factors, P gingivalis infection exacerbated the early stages of atherogenesis in this model. Infected animals displayed evidence of local periodontal infection, as the severity of alveolar bone loss, the hallmark of periodontitis, was increased. Generalized activation of host inflammatory responses was evident in infected mice, as demonstrated by serum IgG response to P gingivalis and elevated levels of interleukin-6. P gingivalis DNA was localized in the aortic tissue from a limited number of infected mice but not in any noninfected controls. Infected mice displayed enhanced vascular activation, as suggested by increased aortic expression of vascular cell adhesion molecule-1 and tissue factor.

CONCLUSIONS

Oral infection with P gingivalis accelerates early atherosclerosis. Thus, uncovering the underlying mechanisms is critical for the design of preventive and therapeutic strategies targeting atherosclerotic vascular disease and its sequelae.

Preterm low birth weight and periodontal disease among African Americans

African Americans consistently experience higher rates of preterm and low birth weight (LBW) deliveries than do whites. LBW and preterm infants are more likely to die before their first birthday and survivors may suffer from a number of health problems. Therefore, identification of modifiable risk factors for preterm deliveries and LBW has considerable public health significance. Pregnant women's poor periodontal healtlh is emerging as one such factor. Maternal clinical periodontal status and bacteriologic and immunologic profiles related to periodontal disease have been associateted with risk of fetal growth and preterm LBW, and periodontal treatment during pregnancy has reduced the incidence of preterm deliveries. This article reviews the literature on the above association and presents data from a previously published prospective study of predominantly African Americans to show that preterm LBW deliveries are associated with higher midtrimester maternal serum antibody levels against Porphyromonas gingivalis.

Actinobacillus actinomycetemcomitans in a rural adult population in southern Thailand

The prevalence of Actinobacillus actinomycetemcomitans isolates was examined in a rural population of southern Thailand. Sixty individuals aged 30-39 and 50-59 years were randomly selected from a group of 363 persons, living in four villages, who had been clinically examined previously. A subgingival plaque sample was taken with a curette from the mesial aspect of the two upper and lower first molars. Each sample was dispersed in 3.3 ml of VMGA III transport medium and spread onto Trypticase Soy Broth with Bacitracin and Vancomycin (TSBV)-agar plates on the same day. After incubation in 10% CO2 for 5 days the plates were examined for typical A. actinomycetemcomitans colonies which were tested for catalase activity. Each strain was further tested for biochemical characteristics, serotyped against serotype-specific antisera a-e and ribotyped after DNA digestion using the restriction endonucleases HindIII and EcoRI. For 53 (88%) of the 60 individuals, A. actinomycetemcomitans was present in at least one subgingival sample, which is considerably higher than the prevalence in Western European adults. In 11 individuals, two or three different strains were found. Serotypes a and c were the most prevalent, and serotype b was found only once among 46 tested isolates. Eleven ribotypes were found among the 46 strains. While the same ribotype could be found among individuals of the same village, no ribotype of A. actinomycetemcomitans was unique for individuals of any one village. The study demonstrated a high prevalence of A. actinomycetemcomitans among adults of the rural population of southern Thailand and indicates that this species is present as part of the resident oral flora in this population.

Simple and rapid detection of serum antibody to periodontopathic bacteria by dot blotting

The aim of this study was to detect the specific immunoglobulin G antibodies against periodontopathic bacteria by dot blotting. In the procedure used, bacterial preparations were blotted on a nitrocellulose membrane. After blocking the nonspecific binding sites, the diluted serum was blotted onto the preparations. The membrane was immersed in secondary antibodies and then in substrate buffer. The colored blots were then evaluated. To test the reliability of this procedure, 20 serum samples were examined for antibody: ten for anti-Porphyromonas gingivalis antibody, and the other ten for anti-Actinobacillus actinomycetemcomitans antibody. Five samples out of each set of ten had previously been confirmed as having high enzyme-linked immunosorbant assay (ELISA) titers to the antigen, while the other five had been confirmed as having average titer levels. Both whole-cell sonic extracts and fimbriae of P. gingivalis were used as antigens in the dot blotting, in order to compare their use as antigens in assays of the patients' sera. ELISA was also used to measure anti-P. gingivalis antibody titers. For the measurement of IgG antibodies against A. actinomycetemcomitans, formalin-killed whole cells were used. Fifty serum samples were examined for IgG antibodies against A. actinomycetemcomitans by dot blotting and ELISA. With both antigens, after 4 h, coloration of blots was more clearly visible for the high-titer sera than for the average-titer sera. The intensity of coloration of the blots for P. gingivalis and A. actinomycetemcomitans showed correlation with the ELISA titers. A particularly significant correlation was shown when P. gingivalis fimbriae were used as antigen. These results suggest that this dot blot method is a simple and rapid means of detection of serum antibodies, and that it shows promise as a chair-side assay method.

Interleukin-1 gene polymorphism and periodontal status

OBJECTIVES

This case-control study examined polymorphisms at the interleukin-1 gene in relation to periodontal status, subgingival bacteria and systemic antibodies to periodontal microbiota.

METHODS

132 periodontitis patients were age- and gender-matched with 73 periodontally intact controls. Full-mouth clinical assessments of the periodontal tissues were performed. Subgingival plaque samples (2440 in total) were analyzed by genomic DNA probes, and serum IgG antibodies to periodontal microbiota were assessed by an immunoassay. Polymorphisms in the IL-1A gene at position +4845 and the IL-1B gene at position +3953 were studied by PCR. A composite positive genotype was defined as at least one rare (#2) allele present at each locus.

RESULTS

No skewed distribution of the composite genotype was observed between cases and controls (45.2% vs 41.7%). In cases, both the composite genotype and the number of #2 alleles were positively correlated with the severity of attachment loss. No relationship between genotype and subgingival microbial profiles was observed. Genotype positive patients revealed both overall lower serum antibody levels and specific titers against selected bacteria.

CONCLUSIONS

The composite genotype failed to distinguish between periodontitis patients and controls but correlated in patients with the severity of the disease and the antibody responses to periodontal microbiota.

Papillon-Lefèvre syndrome: serum immunoglobulin G (IgG) subclass antibody response to periodontopathic bacteria. A case report

BACKGROUND

Papillon-Lefevre syndrome (PLS) is a rare autosomal recessive disorder which is characterized by palmar-plantar hyperkeratosis and rapid periodontal destruction of both primary and permanent dentitions. In this case report, we present clinical features, and microbiological and immunological findings of 40 month-old Thai male PLS patient.

METHODS

Microbiological examinations consisted of bacterial culture methods utilizing selective media, morphological identification, and biochemical tests. In addition, the specific serum IgG subclass antibody titers reactive with etiologic periodontal bacteria were determined by the dot-blot immunological analysis and enzyme linked immunosorbent assay (ELISA).

RESULTS

The examinations revealed that the patient harbored 3 major suspected periodontopathic microorganisms, A. actinomycetemcomitans, P. gingivalis, and P. intermedia. The patient's serum IgG1, IgG2, and IgG3, but not IgG4, titers against A. actinomycetemcomitans were dramatically increased. The predominant IgG subclass was IgG1. In contrast, the IgG titers against other tested bacteria, P. gingivalis, P. intermedia, and F. nucleatum, appeared to be similar to those of a healthy control.

CONCLUSIONS

A. actinomycetemcomitans seems to play a pivotal role in the bacteria-host interaction in PLS periodontal pathogenesis. Response of the specific serum IgG subclass antibody titers against the A. actinomycetemcomitans antigen has been demonstrated. This association warrants further investigation.

Maternal periodontitis and prematurity. Part II: Maternal infection and fetal exposure

Clinical data from the first 812 deliveries from a cohort study of pregnant mothers entitled Oral Conditions and Pregnancy (OCAP) demonstrate that both antepartum maternal periodontal disease and incidence/progression of periodontal disease are associated with preterm birth and growth restriction after adjusting for traditional obstetric risk factors. In the current study we present measures of maternal periodontal infection using whole chromosomal DNA probes to identify 15 periodontal organisms within maternal periodontal plaque sampled at delivery. In addition, maternal postpartum IgG antibody and fetal exposure, as indexed by fetal cord blood IgM level to these 15 maternal oral pathogens, was measured by whole bacterial immunoblots. The potential role of maternal infection with specific organisms within 2 bacterial complexes most often associated with periodontitis, conventionally termed "Orange" (Campylobacter rectus, Fusobacterium nucleatum, Peptostreptococcus micros, Prevotella nigrescens, and Prevotella intermedia) and "Red" (Porphyromonas gingivalis, Bacteroides forsythus, and Treponema denticola) complexes, respectively, to prematurity was investigated by relating the presence of oral infection, maternal IgG, and fetal cord IgM, comparing full-term to preterm (gestational age < 37 weeks). The prevalence of 8 periodontal pathogens was similar among term and preterm mothers at postpartum. There was a 2.9-fold higher prevalence of IgM seropositivity for one or more organisms of the Orange or Red complex among preterm babies, as compared to term babies (19.9% versus 6.9%, respectively, P = 0.0015, chi square). Specifically, the prevalence of positive fetal IgM to C. rectus was significantly higher for preterm as compared to full-term neonates (20.0% versus 6.3%, P = 0.0002, as well as P. intermedia (8.8% versus 1.1%, P = 0.0003). A lack of maternal IgG antibody to organisms of the Red complex was associated with an increased rate of prematurity with an odds ratio (OR) = 2.2; confidence interval (CI) 1.48 to 3.79), consistent with the concept that maternal antibody protects the fetus from exposure and resultant prematurity. The highest rate of prematurity (66.7%) was observed among those mothers without a protective Red complex IgG response coupled with a fetal IgM response to Orange complex microbes (combined OR 10.3; P < 0.0001). These data support the concept that maternal periodontal infection in the absence of a protective maternal antibody response is associated with systemic dissemination of oral organisms that translocate to the fetus resulting in prematurity. The high prevalence of elevated fetal IgM to C. rectus among premature infants raises the possibility that this specific maternal oral pathogen may serve as a primary fetal infectious agent eliciting prematurity.

The association between Porphyromonas gingivalis-specific maternal serum IgG and low birth weight

BACKGROUND

In Alabama, low birth weight (LBW) infants are about 20 times more likely to die before their first birthday compared to normal birth weight infants. While the rate of LBW has been consistently higher among African Americans compared to whites, there has been a gradual increase in LBW for both African Americans and whites over the last 15 years. In an attempt to identify modifiable risk factors for LBW, we have previously reported that a pregnant woman's poor periodontal health may be an independent risk factor for low birth weight.

METHODS

A predominantly African American and socioeconomically homogeneous group of 448 women was followed from the second trimester of their first pregnancy. Thirty-nine LBW cases were observed at the end of follow-up. Using 17 preterm LBW cases and 63 randomly selected controls from the above cohort, the periodontal pathogen-specific maternal serum IgG levels during the second trimester of pregnancy were evaluated in relation to birth weight of the infant, while controlling for known risk factors for LBW.

RESULTS

Porphyromonas gingivalis (P.g.)-specific maternal serum IgG levels were higher in the LBW group (mean 58.05, SE = 20.00 microg/ml) compared to the normal birth weight (NBW) group (mean 13.45, SE = 3.92 microg/ml; P= 0.004). Women with higher levels of P.g.-specific IgG had higher odds of giving birth to LBW infants (odds ratio [OR] = 4.1; 95% confidence interval [CI] for odds ratio = 1.3 to 12.8). This association remained significant after controlling for smoking, age, IgG levels against other selected periodontal pathogens, and race.

CONCLUSIONS

Low birth weight deliveries were associated with a higher maternal serum antibody level against P. gingivalis at mid-trimester.