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.

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.

Periodontal disease at the biofilm-gingival interface.

BACKGROUND: A molecular epidemiologic study provided the opportunity to characterize the biology of the biofilm-gingival interface (BGI) in 6,768 community-dwelling subjects. METHODS: Disease classifications and multivariable models were developed using clinical, microbial, inflammatory, and host-response data. The purpose was to identify new clinical categories that represented distinct biologic phenotypes based upon DNA checkerboard analyses of eight plaque bacteria, serum immunoglobulin G (IgG) titers to 17 bacteria, and the gingival crevicular fluid (GCF) levels of 16 inflammatory mediators. Five BGI clinical conditions were defined using probing depths (PDs) and bleeding on probing (BOP) scores. Subjects with all PDs < or = 3 mm were grouped as BGI-healthy (14.3% of sample) or BGI-gingivitis (BGI-G, 15.1%). Subjects with one or more PDs > or = 4 mm [deep lesion (DL)] were divided into low BOP (18.0%), moderate BOP (BGI-DL/MB, 39.7%), and severe BOP (BGI-DL/SB, 12.9%). RESULTS: Subjects with BGI-G had increased levels of Campylobacter rectus-specific serum IgG levels (P = 0.01), and those with BGI-DL/SB had increased IgG levels to Porphyromonas gingivalis (P < 0.0003) and C. rectus (P < 0.01). BGI-DL/SB subjects had an excessive GCF interleukin (IL)-1beta and prostaglandin E2 response and an enhanced chronic inflammatory response with significant increases in GCF IL-6 and monocyte chemotactic peptide-1. Within BGI-DL/SB subjects, more severe pocketing and BOP were associated with higher levels of GCF IL-1beta, not higher microbial counts or plaque scores. CONCLUSIONS: New BGI classifications create categories with distinct biologic phenotypes. The increased titers of C. rectus IgG among 68.5% of the BGI-G subjects and elevated P. gingivalis titers among BGI-DL/MB and BGI-DL/SB subjects (63.8% and 75.7%, respectively) are strongly supportive of the microbial specificity of pathogenesis for BGI categories.

Effects of 0.12% chlorhexidine gluconate on experimental gingivitis in non-human primates: clinical and microbiological alterations.

OBJECTIVE: This study examined the efficacy of 0.12% chlorhexidine gluconate (Peridex) to reduce gingival inflammation in the absence of mechanical hygiene and its effect on the oral microbial ecology in a non-human primate (NhP) model of gingivitis. DESIGN: Twelve NhP were stratified based on existing inflammation into two groups of six NhP per group. Oral hygiene was performed on both groups so as to reach a level of gingival health (BOP < or = 0.3) at the conclusion of the hygiene phase. One group received 30 ml of 0.12% chlorhexidine gluconate twice daily 7 days/week, and a second group received 30 ml of placebo (distilled water colored to match the active) using the same regimen for 10 weeks. MEASUREMENT OUTCOMES: Clinical parameters including plaque (PLI), pocket depth (PD), attachment level (AL), and bleeding on probing (BOP) were evaluated at 2-week intervals. Subgingival plaque samples were collected by paper point at 2-week intervals and cultured for predominant cultivable bacteria. RESULTS: By week 2, there was a difference in BOP between the groups, which reached statistical significance by week 4. This difference in BOP was maintained throughout the course of the study. Chlorhexidine gluconate (0.12%) had no significant effect on PLI, PD, or AL; although PD was greater in the placebo group after week 2 and throughout the study. Microbiologically, at week 4, the treatment group had a reduction in total bacterial counts, as well as Gram positive bacteria, and total black pigmented bacteria, compared to the placebo group. However, only the differences in Actinomyces spp. reached significance. Interestingly, when both groups received only one treatment/day on the weekends (i.e., day 6 and 7), an associated loss of statistically significant differences between the two groups was observed. Additional experiments dosing the non-human primates once daily, 5 days/week yielded no significant differences in clinical parameters, including bleeding, when compared with the placebo group. CONCLUSION: Non-human primates provided a model system of gingivitis for testing antimicrobial agent effects on the subgingival ecology and accompanying inflammatory responses. Chlorhexidine gluconate (0.12%), even in the absence of mechanical hygiene, was effective in inhibiting clinical signs of inflammation, associated with alterations in the subgingival microbial ecology, most notably Actinomyces spp.

Gingival crevicular fluid inflammatory mediators and bacteriology of gingivitis in nonhuman primates related to susceptibility to periodontitis.

The hypothesis to be tested was that the microbiota and resulting local host inflammatory response characteristics in oral conditions of high levels of chronic gingival inflammation increases susceptibility to progressing periodontitis. This study used cynomolgus monkeys, Macaca fascicularis (nonhuman primates), with high and low levels of long-standing gingival inflammation to define the profiles of gingival crevicular fluid mediators, cytokines and immunoglobulins; describe the subgingival microbiota; and evaluate their susceptibility to ligature-induced periodontitis. Sixteen nonhuman primates were stratified into two groups (HI, LO) based upon Bleeding Index as a measure of the natural level of inflammation (HI = 1.26 +/- 0.45; LO = 0.22 +/- 0.16). The host mediator levels, subgingival microbiota, and clinical characteristics of the LO and HI groups were compared after 30 days of oral hygiene, during a 30 day experimental gingivitis (7, 14, and 30 days), and during periodontitis (30, 60, and 90 days). The results demonstrated that nonhuman primates with high levels of long-standing gingival inflammation when compared to those nonhuman primates with low inflammation show: 1) different inflammatory mediator profiles in gingival crevicular fluid (particularly for immunoglobulin A (IgA) and IgG levels), 2) a different quantitative and qualitative subgingival microbiota; and 3) a similar progression of periodontitis. Thus, while variations in host inflammatory responses to local factors exist in the nonhuman primates, an extensive subgingival challenge (such as ligation) may negate these individual differences.

Changes in gingival crevicular fluid levels of immunoglobulin A following therapy: association with attachment loss.

BACKGROUND: In previous studies, we demonstrated that increased levels of immunoglobulin A (IgA) in gingival crevicular fluid (GCF) may be "protective", while increased levels of the polymorphonuclear lysosomal enzyme, beta-glucuronidase, in GCF were associated with increased risk of disease activity. In this study, we examined the effect of scaling and root planing (SRP) on the levels of beta-glucuronidase, IgG, and IgA in GCF over a 24-week period and compared these to clinical attachment loss (CAL). METHODS: Twenty-nine patients with periodontal disease were examined for attachment level, probing depth, plaque, and bleeding on probing at 6 sites per tooth. GCF was collected from the mesial aspect of all teeth excluding third molars and analyzed for beta-glucuronidase, IgG, and IgA. After baseline data were collected, each patient received SRP, and GCF was collected again at 2, 4, 6, 8, 12, and 24 weeks post-SRP while clinical data were obtained at 4, 8, 12, and 24 weeks. In addition, we analyzed whether the magnitude of the IgA response to SRP would affect the rate of periodontal disease progression by examining GCF IgA levels at 2 time intervals: 2 to 4 weeks post-SRP and 6 to 12 weeks post-SRP. RESULTS: Seventeen patients (58.6%) exhibited at least 1 site losing > or =2.5 mm of CAL during the 24-week study. Beta-glucuronidase in GCF was significantly decreased at 2 weeks following SRP and then demonstrated a gradual increase throughout the study period. Levels of IgA in GCF significantly increased following SRP, reaching a peak at 6 weeks and then gradually decreasing throughout the study. Furthermore, we found an inverse relationship between GCF IgA levels at 6 to 12 weeks post-SRP and the occurrence of CAL. CONCLUSIONS: These results support the hypothesis that maintenance of high levels of IgA in GCF may be "protective" against periodontal attachment loss. Furthermore, levels of beta-glucuronidase appear to be a more sensitive indicator of gingival inflammation than clinical measures.

Systemic manifestations of periodontitis in the non-human primate.

This report describes our findings regarding the potential contribution of periodontitis to atherosclerotic processes using a nonhuman primate model. The goal of the investigations was to target general mechanisms which could describe the association of these disease processes, including: (i) systemic translocation of bacteria/products during periodontitis; (ii) alterations in systemic inflammatory biomarkers during periodontitis; and (iii) the relationship of periodontitis to serum lipids/lipoproteins. Increases in serum endotoxin (e.g. LPS) during ligature-induced periodontitis were observed in these animals. We determined serum levels of various acute phase reactants and chemokines (e.g. CRP, alpha 1-antitrypsin, haptoglobin, fibrinogen, IL-8). A number of these host factors were significantly increased during gingivitis and/or periodontitis. Finally, we observed specific changes in serum lipid levels (cholesterol, triglycerides, HDL, LDL) and lipoproteins (apoA-I) during periodontitis, which were exacerbated by exposure of the animals to a diet with elevated fat content. Thus, we have described systemic manifestations of periodontitis that include detection of bacterial products, inflammatory biomarkers, and dyslipoproteinemia consistent with an increased atherogenic risk.

Immunoglobulin isotypes in gingival crevicular fluid: possible protective role of IgA.

In order to simultaneously assess the local humoral immune and polymorphonuclear leukocyte (PMN) responses in periodontal disease, IgG, IgM, and IgA, as well as the PMN lysosomal enzyme beta-glucuronidase (beta G), were examined in gingival crevicular fluid (GCF) from patients with varying degrees of periodontal pathology. Evaluations were made before and after conservative therapy (scaling and root planing). Thirty patients with varying degrees of periodontal pathology, ranging from mild inflammatory gingivitis to moderate periodontitis, were studied. GCF was collected from the mesial surfaces of all teeth. The presence of the 3 immunoglobulin isotypes was determined by enzyme linked immunosorbent assays (ELISA), while total beta G activity in GCF was determined by a fluorometric assay. Clinical parameters were obtained from 6 sites per tooth. Our data indicate that prior to treatment, total beta G activity is strongly related to the severity of periodontal disease as measured by mean probing attachment level (AL; r = 0.89; P < .005), mean probing depth (PD; 4 = 0.89; P < .0005) and percentage of sites exhibiting bleeding on probing (% BOP; r = 0.49; P < .005). Following treatment, no statistically significant relationship of disease severity and beta G is found. The concentrations of IgG and IgM in GCF do not follow a specific pattern when related to disease severity. In contrast, prior to treatment the concentration of IgA is negatively correlated to mean AL (r = -0.54; P < .005), mean PD (r = -0.59; P < .005), and % BOP (r = -0.47, P < .005).(ABSTRACT TRUNCATED AT 250 WORDS)

The influence of supragingival plaque control on clinical and microbial outcomes following the use of antibiotics for the treatment of periodontitis.

Although supragingival plaque control is essential to successful periodontal therapy, the role of plaque control following systemic antibiotic use in periodontal disease has not been well defined. This study evaluated, following antibiotic use, which clinical and microbial parameters appeared to be influenced primarily by the antibiotics, independent of plaque control, and which outcomes appeared to be dependent on plaque control. Two hundred thirty-six patients (236) with moderate to severe periodontitis were clinically evaluated and microbial samples were taken by their private-practice periodontists. All patients were treated with scaling and root planing and a variety of systemic antibiotics, which were selected based on the microbial and clinical profile of the patient. Three months after therapy, patients were reevaluated and grouped by post-treatment plaque control, as either having very good oral hygiene (LoPl: N = 143; < or = 10% plaque-covered surfaces) or poor oral hygiene (HiPl: N = 93; > or = 25% plaque-covered surfaces). The two groups had different plaque and bleeding scores initially, but similar numbers of pockets probing > 5 mm and similar microbial patterns. Although the LoPl group had a significantly greater reduction in plaque than the HiPl group, bleeding scores and probing depths changed comparably in both groups after antibiotic therapy. Plaque control influenced outcomes significantly, but in a complex manner. The LoPl group exhibited a significantly greater reduction in certain bacteria, for example P. gingivalis. Interactions between plaque control and specific microbial parameters significantly affected clinical outcomes, although neither alone was sufficient to predict outcomes following antibiotic therapy.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of a risk profile for periodontal disease: microbial and host response factors.

Advances in our understanding of the relationship between the microbial challenge and the host response in periodontal disease have led to the search for pathogenesis-based risk indicators or risk factors for disease progression. This evaluation is based on analysis of non-invasive or minimally invasive samples that allow measurement of the subgingival plaque microflora or the host response in gingival crevicular fluid (GCF), serum, or saliva. Studies conducted by us have indicated that in GCF, persistently elevated levels of beta-glucuronidase (beta G, a marker for primary granule release from polymorphonuclear leukocytes) are associated with clinical attachment loss in patients with periodontitis. This finding has been confirmed in a multicenter trial. We have also observed that a statistically significant positive correlation exists between beta G in GCF and measures of the subgingival microbial challenge, but the correlation was less than 0.5, suggesting variations in the host response to the challenge. Furthermore, beta G levels in GCF were inversely correlated with the IgG serum antibody titer to a panel of periodontal pathogens, suggesting the essentially protective function of the systemic humoral response in periodontal disease. Data in the literature support this concept. In addition, recent studies of the relationship of antibody isotypes in GCF to progression of clinical attachment loss have suggested that IgA in GCF has a protective function. This may relate to the lack of complement activation by IgA. Alternately, the development of IgA antigen-specific responses are T-cell dependent, and reductions in local levels of IgA may indicate a decrease in T-helper cell function. These data have allowed development of strategies for identifying individual risk profiles for patients with periodontal disease based on the host response to the microbial challenge. With identification of these risk indicators/risk factors for active periodontal disease, the next challenge is to provide clinicians with access to the tests and analyses that are required for this approach to periodontal diagnosis. Improved patient management should result from the incorporation of these tests into clinical practice.

Butyrate and propionate: important components of toxic dental plaque extracts.

Extracts of in vitro-cultured human dental plaque contain factors toxic to mammalian cells. Previous studies demonstrated that those toxic factors most readily released from cultured plaque had very low molecular weights and were heat stable. Studies reported here demonstrate that metabolic end products including short-chain fatty acids were present in fractions containing the low-molecular-weight, heat-stable factors. The salts of two of these acids, butyrate and propionate, inhibited proliferation of both mouse L929 cells and human gingival fibroblasts. Furthermore, when tested at concentrations present in plaque extracts, the inhibitory effects of butyrate and propionate accounted for essentially all the inhibitory potential of the extracts. These findings, taken together with those of other groups, suggest that butyrate and propionate, end products of dental plaque metabolism, may have an etiological role in periodontal disease.

A comparison of the effects of endotoxin upon fibroblast proliferation and macromolecular syntheses.

The effects of Escherichia coli endotoxin upon mouse L929 cell proliferation, DNA synthesis, protein synthesis, and proline incorporation were determined. It was found that a level of endotoxin which inhibited cell proliferation prompted a similar inhibition of DNA synthesis and overall cell protein synthesis. In contrast, endotoxin was shown to inhibit incorporation of proline into cell protein to a significantly greater extent.