Genetic polymorphisms and periodontal disease in populations of African descent: A review.

Aggressive periodontitis is a rare but rapidly progressing form of periodontal disease that usually affects otherwise systemically healthy individuals, at a young age. It usually affects first molars and incisors, which are usually lost if treatment is not properly and early rendered. Although of low prevalence, it affects individuals of African descent at a higher prevalence, and usually multiple members within the same family. Several studies have been performed in the attempt to evaluate specific single nucleotide polymorphisms (SNPs) that could be associated with this disease. To the best of our knowledge, the present article provides the first review of the literature focusing on studies that evaluated SNPs in patients of African descent with aggressive periodontitis. Several SNPs have been evaluated in different genes according to their role in the pathogenesis of the disease, with positive and negative associations (such as IL1, FCGR3B, FPR1, LTF, CYBA, GLT6D1, TLR4) with both the localized and generalized forms of aggressive periodontitis. Given the complexity of periodontitis, the difficulty in gathering large cohorts diagnosed with this rare form of disease, and the fact that candidate gene studies may only determine part of the genetic risk of a disease, the search for specific SNPs associated with aggressive periodontitis seems to be a long one, most likely to result in the combination of multiple SNPs, in multiple genes.

Virulence of major periodontal pathogens and lack of humoral immune protection in a rat model of periodontal disease.

OBJECTIVE: This study was designed to test the hypothesis that periodontal pathogens Tannerella forsythia and Porphyromonas gingivalis are synergistic in terms of virulence potential using a model of mixed-microbial infection in rats. MATERIALS AND METHODS: Three groups of rats were infected orally with either T. forsythia or P. gingivalis in mono-bacterial infections or as mixed-microbial infections for 12 weeks and a sham-infected group were used as a control. This study examined bacterial infection, inflammation, immunity, and alveolar bone loss changes with disease progression. RESULTS: Tannerella forsythia and P. gingivalis genomic DNA was detected in microbial samples from infected rats by PCR indicating their colonization in the rat oral cavity. Primary infection induced significantly high IgG, IgG2b, IgG1, and IgG2a antibody levels indicating activation of mixed Th1 and Th2 immune responses. Rats infected with the mixed-microbial consortium exhibited significantly increased palatal horizontal and interproximal alveolar bone loss. Histological examinations indicated significant hyperplasia of the gingival epithelium with moderate inflammatory infiltration and apical migration of junctional epithelium. The results observed differ compared to uninfected controls. CONCLUSION: Our results indicated that T. forsythia and P. gingivalis exhibit virulence, but not virulence synergy, resulting in the immuno-inflammatory responses and lack of humoral immune protection during periodontitis in rats.

Focal adhesion integrity is downregulated by the alternatively spliced domain of human tenascin.

Tenascin, together with thrombospondin and SPARC, form a family of matrix proteins that, when added to bovine aortic endothelial cells, caused a dose-dependent reduction in the number of focal adhesion-positive cells to approximately 50% of albumin-treated controls. For tenascin, a maximum response was obtained with 20-60 micrograms/ml of protein. The reduction in focal adhesions in tenascin-treated spread cells was observed 10 min after addition of the adhesion modulator, reached the maximum by 45 min, and persisted for at least 4 h in the continued presence of tenascin. This effect was fully reversible, was independent of de novo protein synthesis, and was neutralized by a polyclonal antibody to tenascin. Monoclonal antibodies to specific domains of tenascin (mAbs 81C6 and 127) were used to localize the active site to the alternatively spliced segment of tenascin. Furthermore, a recombinant protein corresponding to the alternatively spliced segment (fibronectin type III domains 6-12) was expressed in Escherichia coli and was active in causing loss of focal adhesions, whereas a recombinant form of a domain (domain 3) containing the RGD sequence had no activity. Chondroitin-6-sulfate effectively neutralized tenascin activity, whereas dermatan sulfate and chondroitin-4-sulfate were less active and heparan sulfate and heparin were essentially inactive. Studies suggest that galactosaminoglycans neutralize tenascin activity through interactions with cell surface molecules. Overall, our results demonstrate that tenascin, thrombospondin, and SPARC, acting as soluble ligands, are able to provoke the loss of focal adhesions in well-spread endothelial cells.

Integrin-mediated activation of MAP kinase is independent of FAK: evidence for dual integrin signaling pathways in fibroblasts.

Integrin-mediated cell adhesion causes activation of MAP kinases and increased tyrosine phosphorylation of focal adhesion kinase (FAK). Autophosphorylation of FAK leads to the binding of SH2-domain proteins including Src-family kinases and the Grb2-Sos complex. Since Grb2-Sos is a key regulator of the Ras signal transduction pathway, one plausible hypothesis has been that integrin-mediated tyrosine phosphorylation of FAK leads to activation of the Ras cascade and ultimately to mitogen activated protein (MAP) kinase activation. Thus, in this scenario FAK would serve as an upstream regulator of MAP kinase activity. However, in this report we present several lines of evidence showing that integrin-mediated MAP kinase activity in fibroblasts is independent of FAK. First, a beta1 integrin subunit deletion mutant affecting the putative FAK binding site supports activation of MAP kinase in adhering fibroblasts but not tyrosine phosphorylation of FAK. Second, fibroblast adhesion to bacterially expressed fragments of fibronectin demonstrates that robust activation of MAP kinase can precede tyrosine phosphorylation of FAK. Finally, we have used FRNK, the noncatalytic COOH-terminal domain of FAK, as a dominant negative inhibitor of FAK autophosphorylation and of tyrosine phosphorylation of focal contacts. Using retroviral infection, we demonstrate that levels of FRNK expression sufficient to completely block FAK tyrosine phosphorylation were without effect on integrin-mediated activation of MAP kinase. These results strongly suggest that integrin-mediated activation of MAP kinase is independent of FAK and indicate the probable existence of at least two distinct integrin signaling pathways in fibroblasts.

Structure of a fibronectin type III domain from tenascin phased by MAD analysis of the selenomethionyl protein.

Fibronectin type III domains are found in many different proteins including cell surface receptors and cell adhesion molecules. The crystal structure of one such domain from the extracellular matrix protein tenascin was determined. The structure was solved by multiwavelength anomalous diffraction (MAD) phasing of the selenomethionyl protein and has been refined to 1.8 angstrom resolution. The folding topology of this domain is identical to that of the extracellular domains of the human growth hormone receptor, the second domain of CD4, and PapD. Although distinct, this topology is similar to that of immunoglobulin constant domains. An Arg-Gly-Asp (RGD) sequence that can function for cell adhesion is found in a tight turn on an exposed loop.

Aggregatibacter actinomycetemcomitans in African Americans with Localized Aggressive Periodontitis.

This study aims to investigate the prevalence of the highly leukotoxic JP2 sequence versus the minimally leukotoxic non-JP2 sequence of Aggregatibacter actinomycetemcomitans within a cohort of 180 young African Americans, with and without localized aggressive periodontitis (LAP), in north Florida. The study included patients aged 5 to 25 y: 60 LAP patients, 60 healthy siblings (HS), and 60 unrelated healthy controls (HC). Subgingival plaque was collected from LAP sites-diseased (PD ≥5 mm with bleeding on probing) and healthy (PD ≤3 mm with no bleeding on probing)-and from healthy sites of HS and HC. Plaque DNA was extracted and analyzed by polymerase chain reaction for the detection of the JP2 and non-JP2 sequences of A. actinomycetemcomitans. Overall, 90 (50%) subjects tested positive for the JP2 sequence. Fifty (83.33%) LAP subjects were carriers of the highly leukotoxic JP2 sequence, detected in 45 (75%) diseased sites and 34 (56.67%) healthy sites. Additionally, JP2 carriage was found in 16 HS (26.67%) and 24 HC (40%; P < 0.0001, among groups). The non-JP2 sequence was detected in 26 (14.44%) total subjects: 17 (28.33%) LAP patients detected in equal amounts of diseased and healthy sites (n = 11, 18.33%), 6 (10%) HS sites, and 3 (5%) HC sites (P < 0.05, among groups). The JP2 sequence was strongly associated with LAP-diseased sites in young African Americans, significantly more so than the non-JP2 (ClinicalTrials.gov NCT01330719). Knowledge Transfer Statement: Clinicians may use the results of this study to identify susceptible individuals to aggressive periodontitis, potentially leading to more appropriate selection of therapeutic choices.

Epigenetic regulation of inflammation in localized aggressive periodontitis.

BACKGROUND: We have previously demonstrated a Toll-like receptor (TLR)-mediated hyper-responsive phenotype in our cohort of localized aggressive periodontitis (LAP) individuals. However, mechanisms related to this phenotype are still not clear in the literature. The objective of this cross-sectional study is to examine the role of epigenetic regulation, specifically DNA methylation status of genes in the TLR pathway in this cohort. Peripheral blood was collected from 20 LAP patients and 20 healthy unrelated controls. Whole blood was stimulated with 1 µl (100 ng/µl) of purified Escherichia coli lipopolysaccharide (LPS) for 24 h and cyto/chemokines in the supernatants analyzed by Luminex multiplex assays. Genomic DNA extracted from buffy coats prepared from a second tube of whole blood was used for DNA methylation analysis by pyrosequencing of seven TLR signaling genes (FADD, MAP3K7, MYD88, IL6R, PPARA, IRAK1BP1, RIPK2). RESULTS: Significant differences in the methylation status were observed at specific CpG positions in LAP patients compared to healthy controls and interestingly also between severe and moderate LAP. Specifically, subjects with moderate LAP presented hypermethylation of both the upregulating (MAP3K7, MYD88, IL6R, and RIPK2) and downregulating (FADD, IRAK, and PPARA) genes, while severe LAP presented hypomethylation of these genes. Further analysis on CpG sites with significant differences in methylation status correlates with an increased pro-inflammatory cytokine profile for LAP patients. CONCLUSIONS: Our findings suggest that epigenetic modifications of genes in the TLR pathway may orchestrate the thresholds for balancing induction and prevention of tissue destruction during the course of disease, and thus differ significantly at different stages of the disease, where moderate LAP shows hypermethylation and severe LAP shows hypomethylation of several genes. TRIAL REGISTRATION: https://clinicaltrials.gov, NCT01330719.

Local and Plasma Biomarker Profiles in Localized Aggressive Periodontitis.

Localized aggressive periodontitis (LAP) patients possess a systemic hyperinflammatory response after lipopolysaccharide stimulation. However, the levels of inflammatory and bone biomarkers in plasma, as well as possible associations between local and plasma biomarkers, are unknown in LAP. This cross-sectional study aimed to characterize gingival crevicular fluid (GCF) and plasma biomarker profiles in LAP patients, their healthy siblings (HS), and healthy unrelated controls (HC). Fifty-eight LAP subjects, 33 HS, and 49 HC (African Americans, aged 5 to 25 y) were included. Following collection of clinical parameters with GCF and plasma samples, levels of 16 inflammatory and bone resorption biomarkers were determined with Milliplex. Univariate and correlation analyses were performed among all clinical and laboratorial parameters. Discriminant analyses were used to investigate groups of biomarkers discriminating LAP from HS and HC in GCF and plasma. GCF levels of multiple cytokines and chemokines and RANKL:OPG ratio (receptor activator of nuclear factor kappa-B ligand:osteoprotegerin) were higher in LAP disease, most of which positively correlated with probing depth and attachment loss of sampled sites. A group of IL-12p40, IL-6, IL-12p70, IL-2, and MIP-1α discriminated LAP diseased sites from twheir healthy sites, as well as from HS and HC healthy sites. In plasma, only RANKL levels were increased in LAP versus controls, which positively correlated with the percentage of affected sites and deep/bleeding sites. A plasma inflammatory profile including MIP-1α, IL-8, IL-10, and INF-γ could significantly discriminate LAP patients from HS and HC. No correlations were found between GCF and plasma levels of biomarkers. In conclusion, an inflammatory profile including groups of specific biomarkers in GCF and plasma may significantly discriminate LAP from healthy individuals. The hyperinflammatory response previously found in the peripheral blood of LAP patients is dependent on lipopolysaccharide stimulation, apparently resulting mostly in local tissue destruction and changes in biomarker profile, with a slight influence in the systemic inflammatory profile (ClinicalTrials.gov NCT01330719). Knowledge Transfer Statement: The results of this study can be possibly used by clinicians in the future as diagnostic tools for localized aggressive periodontitis. Thus, in the future, with proper consideration of cost, patient preference, chair-side feasibility and ultimately further studies validating the role of GCF markers for disease progression and response to treatment, this information could lead to more appropriate therapeutic decisions and the development of preventive approaches for susceptible patients.

Inflammatory Response Influences Treatment of Localized Aggressive Periodontitis.

We previously reported a systemic hyperinflammatory response to bacterial lipopolysaccharide (LPS) in children with localized aggressive periodontitis (LAP). Additionally, different levels of this response were observed within the LAP group. It is unknown whether this hyperinflammatory response influences the clinical response to periodontal treatment in these children. Therefore, the goal of this study was to evaluate the influence of LPS responsiveness present prior to treatment on the clinical response to treatment within the LAP cohort. Prior to treatment, peripheral blood was collected from 60 African American participants aged 5 to 21 y, free of systemic diseases, and diagnosed with LAP. Blood was stimulated with ultrapure LPS from Escherichia coli, and Luminex assays were performed to quantify 14 cytokine/chemokine levels. Principal component and cluster analyses were used to find patterns of cytokine/chemokine expression among participants and subdivide them into clusters. Three distinct clusters emerged among LAP participants: a high responder group (high level of response for INFg, IL6, and IL12p40), a mixed responder group (low for some and high for other cytokines/chemokines), and a low responder group (low overall cytokine/chemokine response). Periodontal clinical parameters were compared among these groups prior to and 3, 6, and 12 mo following treatment with mechanical debridement and systemic antibiotics. High responders presented the lowest reductions in clinical parameters after treatment, whereas the low responders presented the highest reductions. In our LAP participants, distinct patterns of LPS response were significantly predictive of changes in clinical parameters after treatment. Future studies are needed to evaluate the underlying mechanisms predicting the heterogeneity of LAP activity, severity, and response to treatment (ClinicalTrials.gov NCT01330719).

Influence of Periodontal Therapy on Systemic Lipopolysaccharides in Children with Localized Aggressive Periodontitis.

PURPOSE: A previous study has shown that children with localized aggressive periodontitis (LAP) demonstrate a lipopolysaccharide (LPS) hyper-responsiveness in addition to elevated levels of systemic LPS when compared to periodontally healthy children. The purpose of this study was to evaluate whether periodontal therapy modulates systemic lipopolysaccharide levels and whether these levels may influence clinical outcomes. METHODS: Peripheral blood samples and clinical parameters (probing depth [PD], clinical attachment levels [CAL], percent sites greater than four mm, bleeding on probing [BoP], and visible plaque [P]) were collected from 29 LAP patients prior to and at three, six, and 12 months following scaling and root planning and systemic antibiotics. Serum LPS levels were quantified using a chromogenic assay. RESULTS: Twenty-five patients were compliant with the prescribed antibiotic treatment and demonstrated a significant reduction in LPS as well as overall PD, CAL, and plaque at all time points post-therapy. Additionally LPS reductions correlated with reductions in PD, CAL, and plaque. CONCLUSIONS: Localized aggressive periodontitis therapy with antibiotics plays an important role in reducing systemic lipopolysaccharide levels. Since LPS is a key mediator of the LAP hyperinflammatory response, its systemic reduction is especially important for the successful management of these children.

Guided tissue regeneration. An experimental procedure in beagle dogs.

This preliminary study examined the healing following an experimental procedure designed to facilitate coronal migration of progenitor cells from the periodontal ligament circumferentially on roots of premolar teeth in beagle dogs. Mucoperiosteal flaps were reflected on the buccal and lingual aspects of premolars in six beagle dogs with periodontal disease. Following root preparation, pieces of orthodontic wire were placed interproximally on the crowns to bridge the spaces between teeth. Biobrane, a synthetic membrane bonded to a knitted nylon fabric and coated with collagen, was placed as a physical barrier between the roots and the flaps to be replaced. The membrane extended as a single piece from the cementoenamel junction (CEJ) to overlap the crest of alveolar bone by 3 to 4 mm on both the buccal and lingual surfaces of the three premolars in each quadrant. The membrane was attached to the crowns at the CEJ with resin. The flaps were replaced and sutured. Postoperative care included plaque control and the membranes were removed after 5 weeks. The dogs were sacrificed to provide observation periods of 8 and 16 weeks after placement of membranes. Histologic examination revealed new connective tissue attachment in the apical part of the 8- and 16-week experimental specimens. Some experimental specimens showed new attachment up to 2.94 mm while others showed a long junctional epithelium (JE). Root resorption was also seen in some specimens. These preliminary findings suggest that placement of physical barriers between root surface and flaps may be beneficial in facilitating coronal migration of progenitor cells from the periodontal ligament.

Orientation of gingival fibroblasts in simulated periodontal spaces in vitro. SEM observations.

The present study examined the orientation of gingival fibroblasts in simulated periodontal spaces in vitro. Extracted human teeth were root planed followed by root resection and root canal instrumentation. The middle and cervical thirds of each root were cut transversely to create 600-micron thick sections. Cortical bovine bone was cut, sectioned and contoured to create bone rings 600 micron thick with an internal diameter large enough to accommodate a root slice leaving a circumferential space varying from approximately 0.1 to 1.0 mm. Root slices and bone rings were incubated in a solution of collagenase and hyaluronidase to remove all remaining soft tissue and partially demineralized in EDTA (18%) for 30 minutes. Human gingival fibroblasts (HGF) were plated to confluency in tissue culture dishes. The dentin slices were then gently placed over the HGF monolayer along with bone rings around them to create simulated periodontal spaces. Control root slices were placed without bone rings around them. Cultures were maintained under standard tissue culture conditions. Representative specimens were obtained after 2, 3 and 4 weeks of culture and processed for scanning electron microscopy (SEM). At 2 weeks, the HGF had formed sheets of cells attached to the periphery of the root slices at one end and to the inner surface of bone rings at the other end. The orientation of cell sheets varied from being perpendicular to the periphery of the slice to oblique. At 3 and 4 weeks, the density and size of cell sheets increased and the orientation was maintained.(ABSTRACT TRUNCATED AT 250 WORDS)

Orientation of gingival fibroblasts in simulated periodontal spaces in vitro containing collagen gels.

The present study examined the orientation of cultured human gingival fibroblasts in simulated periodontal spaces in vitro containing three dimensional hydrated collagen gels. Extracted human teeth were root planed followed by root resection and root canal instrumentation. The middle and cervical thirds of each root were cut transversely to create 600-micron thick sections. Cortical bovine bone was cut, sectioned, and contoured to create bone rings 600 micron thick with an internal diameter large enough to accommodate a root slice leaving a circumferential space varying from approximately 0.1 to 1.0 mm. Root slices and bone rings were incubated in an enzyme solution to remove all remaining soft tissues and then completely demineralized in EDTA (18%) for 72 hours. Human gingival fibroblasts (HGF) were plated to confluency in tissue culture dishes. The dentin slices were then gently placed over the HGF monolayer along with bone rings around them to create simulated periodontal spaces. Five days later, when initial cell attachment to the dentin and root slices had occurred, a collagen gel was poured in the space. The cultures were maintained for six weeks and were then processed for transmission electron microscopy. The HGF appeared to have formed multilayered cell sheets extending from the periphery of the root slices to the inner surface of bone rings. The HGF had apparently attached to both the bone and root surfaces. There was a close interaction of cells with the matrix fibrils of the gel. The cells and matrix fibrils were oriented parallel to each other.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal wound healing in the absence of periodontal ligament cells.

This experiment was designed to study the ability of mucoperiosteal flap connective tissue to form new attachment on partially demineralized roots as well as nondemineralized roots in a wound-model where periodontal ligament (PDL) cells are absent, and ingrowth of bone granulation tissue is controlled. After reflecting mucoperiosteal flaps, bone was removed circumferentially around the distal root of mandibular second premolars and the mesial root of mandibular third premolars in five beagle dogs. The roots were completely denuded from the cementoenamel junction to the apex and curetted to remove PDL and cementum. Following root canal filling, the denuded roots on one side were conditioned with citric acid while the contralateral roots served as controls. To prevent bone-derived granulation tissue from contacting denuded roots, sheets of Nuclepore membrane were placed over the exposed bone margins and secured in place with steel ligatures. The flaps were coronally positioned and sutured. Histologic examination was made after three months of healing accompanied by regular plaque control. Both the experimental (acid conditioned) and control roots showed epithelium extending into the apical third of denuded roots and root resorption confined to the root apices. Some experimental specimens showed connective tissue adhesion in the apical third of roots without any new cementum or oriented fibers. Inflammatory cell infiltrate was seen extending to the apical third of denuded roots in both groups. In this model, the flap connective tissue cells failed to form new cementum and inserting fibers. Whether this was the result of inflammation and epithelial downgrowth or the inability of flap connective tissues to form new attachment could not be concluded from the study.

Biology of tooth-cell adhesion.

Guided tissue regeneration appears to be a very promising approach to achieve the regeneration of periodontal tissue. Several important questions remain, such as the role of bone-derived cells, the length of time the physical barriers should be left in place, and whether anatomic factors, such as the morphology of periodontal defects, affect the outcome of the procedure. Potential applications of this procedure include combining bone grafting techniques with guided tissue regeneration, the use of growth factors to enhance periodontal tissue regeneration, and the repairing of bone defects around endosseous implants. Future research in this area is needed to address some of the present concerns and to improve the predictability of this procedure.

LPS-induced inflammatory response after therapy of aggressive periodontitis.

We have reported a lipopolysaccharide (LPS)-induced hyper-inflammatory response in localized aggressive periodontitis (LAP). It is unknown whether treatment is able to modulate this LPS responsiveness. Fifty-nine individuals with LAP were treated by mechanical debridement and systemic antibiotics. Clinical parameters and cyto/chemokine responsiveness of whole blood stimulated with Porphyromonas gingivalis or Escherichia coli LPS were monitored at baseline and 3, 6, and 12 months post-treatment. Overall, clinical parameters were improved following treatment. Additionally, P. gingivalis LPS induction of eotaxin, IFNγ, IL10, IL12p40, IL1ß, IL6, IP10, MCP1, MIP1α, GM-CSF, and TNFα was significantly decreased (p < .05). Similarly, induction of eotaxin, INFγ, IL10, IL12p40, GM-CSF, and TNFα by E. coli LPS was also reduced post-treatment. These reductions correlated with decreases in clinical parameters. Importantly, these reductions in LPS responsiveness were most robust at 3 months, and some lost significance at 6 to 12 months post-treatment. In conclusion, LPS-induced hyper-inflammatory response in LAP can be partially modulated by periodontal therapy. Conversely, rebound in the hyper-responsiveness of some mediators, in the presence of improved clinical parameters, suggests that this phenotype could be partially influenced by a genetic trait and play a role in future disease recurrence (ClinicalTrials.gov, NCT01330719).

Microbiological characterization in children with aggressive periodontitis.

UNLABELLED: The objective of this study was to characterize the subgingival microbiota of African-American children with Localized Aggressive Periodontitis (LAP). Fifty-one children were included. Subgingival plaque samples were taken from diseased (DD) and healthy sites (DH) in LAP and from healthy sites in HS and HC and analyzed by 16S rRNA-based microarrays. Aggregatibacter actinomycetemcomitans (Aa) was the only species found to be both more prevalent (OR = 8.3, p = 0.0025) and abundant (p < 0.01) in DD. Filifactor alocis (Fa) was also found to be more prevalent in DD (OR 2.31, CI 1.06-5.01, p = 0.03). Most prevalent species in healthy sites were Selenomonas spp, Veillonella spp, Streptococcus spp, Bergeyella sp, and Kingella oralis. Overall, Streptococcus spp, Campylobacter gracilis, Capnocytophaga granulosa, Haemophilus parainfluenzae, and Lautropia mirabilis were most abundant in healthy children, while Aa, Fa, Tannerella sp, Solobacterium moorei, Parvimonas micra, and Capnocytophaga sp were most abundant in LAP. Based on a comprehensive analysis with 16S rRNA-based microarrays, Aa was strongly associated and site-specific in LAP. In contrast, other species were found to be associated with healthy sites and individuals (ClinicalTrials.gov number CT01330719). ABBREVIATIONS: healthy site in healthy sibling (HS); healthy site in healthy control child (HC).

Local inflammatory markers and systemic endotoxin in aggressive periodontitis.

While much research has focused on local and systemic factors contributing to periodontal disease, little is known regarding mechanisms linking these factors. We have previously reported a systemic hyper-inflammatory response to bacterial endotoxin in localized aggressive periodontitis (LAP). The objectives of this study were to delineate cyto/chemokines in gingival crevicular fluid (GCF) and evaluate systemic levels of endotoxin associated with LAP. Clinical parameters, GCF, and peripheral blood were collected from: 34 LAP, 10 healthy siblings, and nine healthy unrelated control individuals. Cyto/chemokines were quantified in GCF, systemic endotoxin levels were quantified in plasma, and correlation analysis was performed among all parameters. Nine mediators were elevated in LAP diseased sites as compared with healthy sites (TNFα, INFγ, IL1ß, IL2, IL6, IL10, Il12p40, GMCSF, and MIP1α, p < 0.001), while MCP1, IL4, and IL8 were elevated in healthy sites (p < 0.01). Four- to five-fold-higher endotoxin levels were detected in LAP plasma compared with that from healthy participants (p < 0.0001), which correlated with all clinical parameters and most cyto/chemokines analyzed. In conclusion, higher systemic levels of endotoxin were found in LAP, which correlates with an exacerbated local inflammatory response and clinical signs of disease. (Clinicaltrials.gov number, NCT01330719).

Hyper-responsive phenotype in localized aggressive periodontitis.

The 'hyper-responsive' trait is an increased inflammatory response upon stimulation of innate immune receptors. Our objective was to determine if a hyper-reactive trait is present in a cohort diagnosed with aggressive periodontitis (LAgP). Peripheral blood was collected from 30 LAgP, 10 healthy unrelated, and 10 healthy sibling participants and stimulated with lipopolysaccharide (LPS) from E. coli and P. gingivalis. Cyto/chemokine response profiles were evaluated and analyzed by ANOVA. Elevated levels of pro-inflammatory cyto/chemokines were detected in E. coli and P. gingivalis LPS-stimulated LAgP cultures when compared with those of healthy unrelated control individuals. Periodontally healthy siblings presented with attenuated hyper-inflammatory cyto/chemokine profiles. Regression analysis demonstrated the hyper-reactive trait to be concomitant expression of pro-inflammatory cyto/chemokines and an absence of anti-inflammatory mediator expression. Our findings demonstrate hyper-responsive trait in a LAgP cohort, along with an attenuated hyper-responsiveness in healthy siblings, which can be induced in response to multiple TLR ligations.

The potential contributions of cell and molecular biology to periodontal tissue regeneration.

Periodontal disease results in the gradual loss of supporting periodontal tissues, and ultimately, the teeth. Although conventional periodontal therapy can arrest the progression of the disease and allow healing, the resulting tissue is unlike that of the normal, healthy periodontium. Cellular and molecular biologic techniques may facilitate our understanding of the regeneration of the periodontium. This review discusses recent findings in cellular and molecular biology relevant to the biology of periodontal tissue regeneration.