Romanita Celenti

The Influence of Interleukin Gene Polymorphism on Expression of Interleukin-1β and Tumor Necrosis Factor-α in Periodontal Tissue and Gingival Crevicular Fluid

BACKGROUND A specific composite genotype of the polymorphic interleukin-1 (IL-1) gene cluster has recently been associated with severe periodontitis. One polymorphism of the composite periodontitis-associated genotype (PAG) has been functionally linked with expression of high levels of IL-1. The purpose of this study was to test whether gingival crevicular fluid (GCF) levels of IL-1ß and tumor necrosis factor-alpha (TNFα), and gingival tissue levels of IL- 1α, IL-1β, and TNFα correlate with PAG, and to examine the effec; of conservative periodontal therapy on these levels. METHODS Twenty-two adults with moderate to advanced periodontal disease were enrolled. Polymerase chain reaction amplification and restriction enzymes were used to identify specific polymorphisms from peripheral blood samples. GCF samples were collected at baseline and 3 weeks following conservative treatment and analyzed by ELISA for IL-1ß and TNFα. An interproximal gingival biopsy was collected at baseline and follow-up and analyzed for IL-1α, IL-1β, and TNFα by ELISA. RESULTS The genotyping identified 7 as PAG(+) and 15 as PAG(-). The 2 groups were comparable in terms of existing periodontitis and age. In shallow sites (<4 mm), total IL-1ß in GCF was 2.5 times higher for PAG(+) patients prior to treatment (P = 0.03), and 2.2 times higher after treatment (P = 0.04), while differences were less apparent in deeper sites. Following treatment, a reduction in IL-1β concentration in GCF was seen for PAG(-) but not for PAG(+) patients. While not statistically significant, a trend was observed in mean tissue levels of IL-1β which were 3.6 times higher in PAG(+) versus PAG(-) patients (P = 0.09). CONCLUSIONS These data suggest that PAG(+) patients may demonstrate phenotypic differences as indicated by elevated levels of IL-1ß in GCF. J Periodontol 1999;70:567-573.

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.

MicroRNAs and Their Target Genes in Gingival Tissues

To gain insights into the in vivo function of miRNAs in the context of periodontitis, we examined the occurrence of miRNAs in healthy and diseased gingival tissues and validated their in silico-predicted targets through mRNA profiling using whole-genome microarrays in the same specimens. Eighty-six individuals with periodontitis contributed 198 gingival papillae: 158 ‘diseased’ (bleeding-on-probing, PD > 4 mm, and AL ≥ 3 mm) and 40 ‘healthy’ (no bleeding, PD ≤ 4 mm, and AL ≤ 2 mm). Expression of 1,205 miRNAs was assessed by microarrays, followed by selected confirmation by quantitative RT-PCR. Predicted miRNA targets were identified and tested for enrichment by Gene Set Enrichment Analysis (GSEA). Enriched gene sets were grouped in functional categories by DAVID and Ingenuity Pathway Analysis. One hundred fifty-nine miRNAs were significantly differentially expressed between healthy and diseased gingiva. Four miRNAs (hsa-miR-451, hsa-miR-223, hsa-miR-486-5p, hsa-miR-3917) were significantly overexpressed, and 7 (hsa-miR-1246, hsa-miR-1260, hsa-miR-141, hsa-miR-1260b, hsa-miR-203, hsa-miR-210, hsa-miR-205*) were underexpressed by > 2-fold in diseased vs. healthy gingiva. GSEA and additional filtering identified 60 enriched miRNA gene sets with target genes involved in immune/inflammatory responses and tissue homeostasis. This is the first study that concurrently examined miRNA and mRNA expression in gingival tissues and will inform mechanistic experimentation to dissect the role of miRNAs in periodontal tissue homeostasis and pathology.

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 pathogenesisbased 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 β-glucuronidase (βG, 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 βG 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, βG 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. J Periodontol 1994;65:511-520.

Subgingival bacterial colonization profiles correlate with gingival tissue gene expression

BackgroundPeriodontitis is a chronic inflammatory disease caused by the microbiota of the periodontal pocket. We investigated the association between subgingival bacterial profiles and gene expression patterns in gingival tissues of patients with periodontitis. A total of 120 patients undergoing periodontal surgery contributed with a minimum of two interproximal gingival papillae (range 2-4) from a maxillary posterior region. Prior to tissue harvesting, subgingival plaque samples were collected from the mesial and distal aspects of each tissue sample. Gingival tissue RNA was extracted, reverse-transcribed, labeled, and hybridized with whole-genome microarrays (310 in total). Plaque samples were analyzed using checkerboard DNA-DNA hybridizations with respect to 11 bacterial species. Random effects linear regression models considered bacterial levels as exposure and expression profiles as outcome variables. Gene Ontology analyses summarized the expression patterns into biologically relevant categories.ResultsWide inter-species variation was noted in the number of differentially expressed gingival tissue genes according to subgingival bacterial levels: Using a Bonferroni correction (p < 9.15 × 10-7), 9,392 probe sets were differentially associated with levels of Tannerella forsythia, 8,537 with Porphyromonas gingivalis, 6,460 with Aggregatibacter actinomycetemcomitans, 506 with Eikenella corrodens and only 8 with Actinomyces naeslundii. Cluster analysis identified commonalities and differences among tissue gene expression patterns differentially regulated according to bacterial levels.ConclusionOur findings suggest that the microbial content of the periodontal pocket is a determinant of gene expression in the gingival tissues and provide new insights into the differential ability of periodontal species to elicit a local host response.

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.

Serum Antibody Responses to Periodontal Microbiota in Chronic and Aggressive Periodontitis: A Postulate Revisited

BACKGROUND The authors revisited the 1999 International Workshop postulate of robust serum antibody responses to infecting agents in localized aggressive periodontitis (LAgP) and weak responses in generalized aggressive periodontitis (GAgP). Antibody responses were further examined in localized and generalized chronic periodontitis (LCP and GCP). METHODS The study includes 119 patients (60 males and 59 females, aged 11 to 76 years), 18 with LAgP, 37 with GAgP, 37 with LCP, and 27 with GCP. Multiple subgingival plaque samples/patient (1,057 in total) were analyzed with respect to 11 bacterial species using checkerboard DNA-DNA hybridizations, and serum immunoglobulin (Ig)G levels were measured against the same bacteria using checkerboard immunoblotting. Further, infection ratios (antibody level over the average bacterial colonization by the homologous species) were computed for each patient. Comparisons of bacterial colonization, serum IgG levels, and infection ratios were made across the diagnostic categories using multivariable linear regression models adjusting for age and race/ethnicity. RESULTS There were no statistically significant differences in serum IgG levels to Aggregatibacter actinomycetemcomitans among the four diagnostic categories. IgG levels to several species, including Porphyromonas gingivalis, Treponema denticola, and Campylobacter rectus, were highest in patients with GAgP and significantly different from LCP and GCP, but not from LAgP. Comparisons based on infection ratios showed no statistically significant differences for any species between GAgP and LAgP. CONCLUSION This study provides evidence against the 1999 Workshops postulate of weak serum antibody responses in patients with GAgP and shows that serum IgG responses in GAgP are comparable to those in LAgP, but higher than in GCP or LCP for several species.

Circulating endothelial progenitor cells in periodontitis.

BACKGROUND Several biologically plausible mechanisms have been proposed to mediate the association between periodontitis and atherosclerotic vascular disease (AVD), including adverse effects on vascular endothelial function. Circulating endothelial progenitor cells (cEPCs) are known to contribute to vascular repair, but limited data are available regarding the relationship between cEPC levels and periodontitis. The aims of this cross-sectional study are to investigate the levels of hemangioblastic and monocytic cEPCs in patients with periodontitis and periodontally healthy controls and to associate cEPC levels with the extent and severity of periodontitis. METHODS A total of 112 individuals (56 patients with periodontitis and 56 periodontally healthy controls, aged 26 to 65 years; mean age: 43 years) were enrolled. All participants underwent a full-mouth periodontal examination and provided a blood sample. Hemangioblastic cEPCs were assessed using flow cytometry, and monocytic cEPCs were identified using immunohistochemistry in cultured peripheral blood mononuclear cells. cEPC levels were analyzed in the entire sample, as well as in a subset of 50 pairs of patients with periodontitis/periodontally healthy controls, matched with respect to age, sex, and menstrual cycle. RESULTS Levels of hemangioblastic cEPCs were approximately 2.3-fold higher in patients with periodontitis than periodontally healthy controls, after adjustments for age, sex, physical activity, systolic blood pressure, and body mass index (P = 0.001). A non-significant trend for higher levels of monocytic cEPCs in periodontitis was also observed. The levels of hemangioblastic cEPCs were positively associated with the extent of bleeding on probing, probing depth, and clinical attachment loss. Hemangioblastic and monocytic cEPC levels were not correlated (Spearman correlation coefficient 0.03, P = 0.77), suggesting that they represent independent populations of progenitor cells. CONCLUSION These findings further support the notion that oral infections have extraoral effects and document that periodontitis is associated with a mobilization of EPCs from the bone marrow, apparently in response to systemic inflammation and endothelial injury.

Serum antibodies to periodontal pathogens are associated with incident Alzheimer's disease

P3-131 SERUM ANTIBODIES TO PERIODONTAL PATHOGENS ARE ASSOCIATEDWITH INCIDENT ALZHEIMER’S DISEASE James Noble, Nikolaos Scarmeas, Romanita Celenti, Mitchell Elkind, Clinton Wright, Nicole Schupf, Panos Papapanou, Taub Institute, Columbia University Medical Center, New York, New York, United States; Columbia University, New York, New York, United States; Columbia University Medical Center, New York, New York, United States; Evelyn F. McKnight Brain Institute, Miami, Florida, United States.