The interplay of lipopolysaccharide-binding protein and cytokines in periodontal health and disease

In-silico exploration of Attukal Kizhangu L. compounds: Promising candidates for periodontitis treatment

A medicinal pteridophyte known as Attukal Kizhangu L. has been used to cure patients for centuries by administering plant parts based on conventional and common practices. Regarding its biological functions, significant use and advancement have been made. Extract of Attukal Kizhangu L. is the subject of the current study, which uses network pharmacology as its foundation. Three targeted compounds such as α-Lapachone, Dihydrochalcone, and Piperine were chosen for additional research from the 17 Phytoconstituents that were filtered out by the Coupled UPLC-HRMS study since they followed to Lipinski rule and showed no toxicity. The pharmacokinetics and physicochemical properties of these targeted compounds were analyzed by using three online web servers pkCSM, Swiss ADME, and Protox-II. This is the first in silico study to document these compound's effectiveness against the standard drug DOX in treating Periodontitis. The Swiss target prediction database was used to retrieve the targets of these compounds. DisGeNET and GeneCards were used to extract the targets of periodontitis. The top five hub genes were identified by Cytoscape utilizing the protein-protein interaction of common genes, from which two hub genes and three binding proteins of collagenase enzymes were used for further studies AA2, PGE2, PI2, TNFA, and PGP. The minimal binding energy observed in molecular docking, indicative of the optimal docking score, corresponds to the highest affinity between the protein and ligand. To corroborate the findings of the docking study, molecular dynamics (MD) simulations, and MMPBSA calculations were conducted for the complexes involving AA2-α-LPHE, AA2-DHC, and AA2-PPR. This research concluded that AA2-DHC was the most stable complex among the investigated interactions, surpassing the stability of the other complexes examined in comparison with the standard drug DOX. Overall, the findings supported the promotion of widespread use of Attukal Kizhangu L. in clinics as a potential therapeutic agent or may be employed for the treatment of acute and chronic Periodontitis.

Systematic review of ratios between disease /health periodontitis modulators and meta-analysis of their levels in gingival tissue and biological fluids

OBJECTIVE

The ratio between molecules which acts towards the diseased or healthy phenotype determine whether the periodontitis lesions will progress or stabilize. Considering gingival tissue and biofluids, we aimed to present a systematic review (qualitative analysis) on the ratios between disease/health periodontitis modulators, and a meta-analysis (quantitative analysis) of their levels in individuals with periodontitis compared to controls.

DESIGN

Electronic searches of the PubMed, Scopus, EMBASE and Web of Science databases were conducted for publications up to May 2020.

RESULTS

A total of 53 publications were included in the systematic review, being 22 of them focusing on the ratios between Interleukin [IL]-1/IL-10, IL-6/IL-10, IL-1/IL-1RA and RANKL/OPG. Twenty-one publications were eligible for meta-analyses. The ratios of IL-1, IL-6 and RANKL mRNA levels were significantly higher in diseased gingival tissue, as well as their protein levels in gingival crevicular fluid (GCF) of periodontitis individuals. Considering the saliva levels, the RANKL/OPG ratio was higher in periodontitis subjects in comparison to controls. Meta-analyses showed higher IL-1β, IL-1α, IL-6 and IL-10 gene expressions in gingival tissue and protein levels in GCF, while RANKL was higher in GCF of periodontitis individuals in comparison to controls.

CONCLUSIONS

Both the ratios and meta-analyses showed higher levels of modulators in gingival tissue and GCF of diseased individuals.

Validation and verification of predictive salivary biomarkers for oral health

Oral health is important not only due to the diseases emerging in the oral cavity but also due to the direct relation to systemic health. Thus, early and accurate characterization of the oral health status is of utmost importance. There are several salivary biomarkers as candidates for gingivitis and periodontitis, which are major oral health threats, affecting the gums. These need to be verified and validated for their potential use as differentiators of health, gingivitis and periodontitis status, before they are translated to chair-side for diagnostics and personalized monitoring. We aimed to measure 10 candidates using high sensitivity ELISAs in a well-controlled cohort of 127 individuals from three groups: periodontitis (60), gingivitis (31) and healthy (36). The statistical approaches included univariate statistical tests, receiver operating characteristic curves (ROC) with the corresponding Area Under the Curve (AUC) and Classification and Regression Tree (CART) analysis. The main outcomes were that the combination of multiple biomarker assays, rather than the use of single ones, can offer a predictive accuracy of > 90% for gingivitis versus health groups; and 100% for periodontitis versus health and periodontitis versus gingivitis groups. Furthermore, ratios of biomarkers MMP-8, MMP-9 and TIMP-1 were also proven to be powerful differentiating values compared to the single biomarkers.

Effect of periodontitis on oxidative stress parameters in patients with rheumatic heart valve disease

OBJECTIVE

The aim of this study was to evaluate the effects of periodontitis on oxidative stress parameters by investigating serum and gingival crevicular fluid (GCF) total antioxidant capacity (TAOC), total oxidant status (TOS), and oxidative stress index (OSI) values in patients with rheumatic heart valve disease (RHVD).

MATERIALS AND METHODS

The study population comprised 76 patients, who were divided into four groups: chronic periodontitis with RVHD (RV-CP), periodontally healthy with RVHD (RV-C), systemically healthy with chronic periodontitis (CP), and systemically and periodontally healthy (C). Demographic, periodontal, and echocardiographic parameters were measured. Serum and GCF oxidative stress parameters were evaluated based on the OSI.

RESULTS

Similar serum oxidative stress parameters were found in all study groups (P ≥ 0.05). The GCF TAOC values of the C group were significantly higher than those of the other groups (P = 0.001). The GCF OSI values of the C group were significantly lower than those of the other groups (P = 0.001). The GCF TOS and OSI values of the RV-CP group were significantly higher than those of the CP and C groups (P = 0.001). The GCF TOS value of the RV-C group was significantly higher than those of the CP and C groups (P = 0.001).

CONCLUSIONS

Altered local oxidative stress profile was associated with the presence of periodontitis. Rheumatic heart valve disease may increase oxidative stress in individuals with chronic periodontitis.

Characterization of Cytokines and Proliferation Marker Ki67 in Cleft Affected Lip Tissue

Background and objectives: Cleft lip palate takes the second place among all anomalies. The complex appearance of cytokines and proliferation markers has still not been clarified despite their possible crucial role in cleft tissue. Therefore, the aim of work was the detection of appearance of pro- and anti-inflammatory cytokines and proliferation marker Ki67, and their inter-correlations in cleft affected lip (CAL). Materials and Methods: The lip material was obtained from 16 children aged before primary dentition during plastic surgery. Control was obtained from 7 non-CAL oral tissue. Tissues were stained for IL-1, IL-4, IL-6, IL-8, IL-10 and Ki67 immunohistochemically. Non-parametric statistic, Mann-Whitney and Spearman's coefficient were used. Results: All cytokines positive cells were observed more into the epithelium. Statistically significant difference was seen between epithelial IL-1, IL-10, IL-8 and Ki67 positive cells and IL-10-, IL-4-containing connective tissue cells in comparison to the control. Strong positive correlation was detected in CAL epithelium between IL-10 and IL-8, IL-10 and IL-4, IL-10 and IL-1, IL-1 and IL-8, IL-1 and IL-4, IL-4 and IL-8, IL-8 and Ki67, IL-10 and Ki67, but moderate-in connective tissue between IL-1 and IL-10, IL-1 and IL-4. Conclusion: The CAL epithelium is the main source for the interleukins. Rich similar expression of IL-1 and IL-10 suggests the balance between pro-and anti-inflammatory tissue response on basis of dysregulated tissue homeostasis (increase of IL-8). The correlations between the different ILs -1, -4, -8, -10 in CAL epithelium seem to indicate the self-protection compensatory mechanism for intensification of local inflammatory-immune response without involvement of IL-6. The correlations between Ki67 and cytokines indicate the involvement of IL-8 and IL-10 in stimulation of cellular proliferation. IL-4 and IL-10 expression from CAL connective tissue simultaneously to IL-1, IL-4 and IL-10 inter-correlations there suggests the intensification of local immune response regulated probably by main pro-inflammatory cytokine-IL-1.

Periodontal Condition and Immunological Aspects of Individuals Hospitalized in the Intensive Care Unit

There are few studies on the clinical and immunological periodontal status of intensive care unit (ICU) in-patients. The aim of the present study was to evaluate the periodontal condition among ICU in-patients through clinical and immunological periodontal parameters. From the sample of 373 hospitalized ICU patients, 182 were submitted' to a thorough clinical periodontal and immunological evaluation. Data on bleeding on probing (BOP), probing depth (PD), and clinical attachment level (CAL) were collected and gingival sulcular fluid samples were quantified through ELISA on IL-1, IL-6, and MMP-2 for immunological evaluation. Data was statistically analyzed by Chi-square, Fisher's exact, Mann-Whitney tests, and Sperman's correlation and multivariate logistic regression analysis. A high dental plaque index and a high prevalence of periodontitis (48.3%), mostly in moderate and localized chronic form, were observed. Individuals with periodontitis presented higher levels of IL-1 and MMP-2, while individuals with cardiovascular disease (CVD) and individuals with two or more systemic diseases (MSD) presented higher levels of IL-1; diabetes mellitus (DM) and MSD individuals presented higher levels of IL-6. A positive association was found between the severity of periodontitis and CVD (OR 2.2; CI = 1.11-4.42). This study reported a 48.3% of the prevalence of periodontitis in ICU patients and a positive association between the severity of periodontitis and CVD. Additionally, higher levels of IL-1 and MMP-2 were found in individuals with periodontitis, higher levels of IL-6 were found in individuals with DM, and higher levels of IL-1 were found in individuals with CVD.

Quantitative proteomic study of the plasma reveals acute phase response and LXR/RXR and FXR/RXR activation in the chronic unpredictable mild stress mouse model of depression

Major depressive disorder is a severe neuropsychiatric disease that negatively impacts the quality of life of a large portion of the population. However, the molecular mechanisms underlying depression are still unclear. The pathogenesis of depression involves several brain regions. However, most previous studies have focused only on one specific brain region. Plasma and brain tissues exchange numerous components through the blood-brain barrier. Therefore, in the present study, plasma samples from control (CON) mice and mice subjected to chronic unpredictable mild stress (CUMS) were used to investigate the molecular pathogenesis of depression, and the association between the peripheral circulation and the central nervous system. A total of 47 significant differentially expressed proteins were identified between the CUMS and CON group by an isobaric tag for relative and absolute quantitation (iTRAQ) coupled with tandem mass spectrometry approach. These 47 differentially expressed proteins were analyzed with ingenuity pathway analysis (IPA) software. This revealed that the acute phase response, LXR/RXR and FXR/RXR activation, the complement system and the intrinsic prothrombin activation pathway were significantly changed. Four of the significant differentially expressed proteins (lipopolysaccharide binding protein, fibrinogen β chain, α-1 antitrypsin, and complement factor H) were validated by western blotting. the present findings provide a novel insight into the molecular pathogenesis of depression.

ROLE OF INNATE IMMUNITY FACTORS IN PERIODONTITIS PATHOGENESIS

Chronic generalized periodontitis (CGP) is a disease of periodontium tissues supporting tooth induced by bacteria, that is characterized by the presence of processes of inflammation with destruction ofbone tissue. The knowledge of molecular mechanisms of CGP pathogenesis facilitates creation of the most effective methods of therapy of this disease. Bacterial infection is a primary factor in periodontitis etiology, however is not sufficient for its start and subsequent development. It is known, that bacterial factors induce a local inflammation reaction and activate the system of innate immunity through activation of Toll-like receptors (TLR), located on the surface of resident cells and leukocytes. Activation of these cells results in production of pro-inflammatory cytokines and recruitment of phagocytes and lymphocytes into the inflammation zone. In review we examined the known data regarding factors of immune protection of periodontium including cell populations and cytokines, as well as mechanisms of tissue destruction, that support the tooth. Perspectives of therapy are also discussed.

Alzheimer's disease and periodontitis--an elusive link

Alzheimer's disease is the preeminent cause and commonest form of dementia. It is clinically characterized by a progressive descent in the cognitive function, which commences with deterioration in memory. The exact etiology and pathophysiologic mechanism of Alzheimer's disease is still not fully understood. However it is hypothesized that, neuroinflammation plays a critical role in the pathogenesis of Alzheimer's disease. Alzheimer's disease is marked by salient inflammatory features, characterized by microglial activation and escalation in the levels of pro-inflammatory cytokines in the affected regions. Studies have suggested a probable role of systemic infection conducing to inflammatory status of the central nervous system. Periodontitis is common oral infection affiliated with gram negative, anaerobic bacteria, capable of orchestrating localized and systemic infections in the subject. Periodontitis is known to elicit a "low grade systemic inflammation" by release of pro-inflammatory cytokines into systemic circulation. This review elucidates the possible role of periodontitis in exacerbating Alzheimer's disease. Periodontitis may bear the potential to affect the onset and progression of Alzheimer's disease. Periodontitis shares the two important features of Alzheimer's disease namely oxidative damage and inflammation, which are exhibited in the brain pathology of Alzheimer's disease. Periodontitis can be treated and hence it is a modifiable risk factor for Alzheimer's disease.

The implication of periodontitis in vascular endothelial dysfunction

BACKGROUND

Periodontitis is the most common oral infection seen in humans worldwide. It is characterized by gradual destruction of tooth supporting tissues, eventually leading to loss of tooth. The periodontal biofilm associated with periodontitis comprises of gram-positive and gram-negative bacteria, instrumental for the initiation and progression of periodontitis. Evidence-based literature has identified the nature of periodontal infection as a possible causative condition in the inducement of 'low-grade systemic inflammation and infection'. The periodontal pathogens exert systemic effects via the haematogenous route.

AIM

The present review provides an insight into the pathophysiology of the endothelial dysfunction with reference to periodontal infection and highlights the association between periodontitis and endothelial dysfunction. Various studies addressing the implication of periodontitis on endothelial dysfunction will be described, with a focus of periodontal treatment on improvement of endothelial function.

MATERIALS AND METHODS

Studies examining the effects of periodontitis on vascular endothelial function were segregated. Studies conducted on both animal and human models were identified using MEDLINE database search with key search terms such as 'Periodontitis', 'vascular endothelium', 'endothelial dysfunction', 'periodontal bacteria' and 'periodontal therapy'. Systematic reviews and meta-analysis were also screened. Only studies published in English language were considered. The review has been prepared by screening MEDLINE database from 1989 to 2012.

RESULTS AND CONCLUSIONS

Chronic periodontitis results in altered vascular response, increased expression of pro-inflammatory cytokines and adhesion molecules inducing vascular endothelial dysfunction. Periodontal therapy may ameliorate the perturbed vascular endothelial function.

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

AIM

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Tetra- and penta-acylated lipid A structures of Porphyromonas gingivalis LPS differentially activate TLR4-mediated NF-κB signal transduction cascade and immuno-inflammatory response in human gingival fibroblasts

Background

Porphyromonas gingivalis is a major pathogen of periodontal disease that affects a majority of adults worldwide. Increasing evidence shows that periodontal disease is linked to various systemic diseases like diabetes and cardiovascular disease, by contributing to increased systemic levels of inflammation. Lipopolysaccharides (LPS), as a key virulent attribute of P. gingivalis, possesses significant amount of lipid A heterogeneity containing tetra- (LPS_1435/1449) and penta-acylated (LPS₁₆₉₀) structures. Hitherto, the exact molecular mechanism of P. gingivalis LPS involved in periodontal pathogenesis remains unclear, due to limited understanding of the specific receptors and signaling pathways involved in LPS-host cell interactions.

Methodology/Principal Findings

This study systematically investigated the effects of P. gingivalis LPS_1435/1449 and LPS₁₆₉₀ on the expression of TLR2 and TLR4 signal transduction and the activation of pro-inflammatory cytokines IL-6 and IL-8 in human gingival fibroblasts (HGFs). We found that LPS_1435/1449 and LPS₁₆₉₀ differentially modulated TLR2 and TLR4 expression. NF-κB pathway was significantly activated by LPS₁₆₉₀ but not by LPS_1435/1449. In addition, LPS₁₆₉₀ induced significant expression of NF-κB and p38 MPAK pathways-related genes, such as NFKBIA, NFKB1, IKBKB, MAP2K4 and MAPK8. Notably, the pro-inflammatory genes including GM-CSF, CXCL10, G-CSF, IL-6, IL-8 and CCL2 were significantly upregulated by LPS₁₆₉₀ while down-regulated by LPS_1435/1449. Blocking assays confirmed that TLR4-mediated NF-κB signaling was vital in LPS₁₆₉₀-induced expression of IL-6 and IL-8 in HGFs.

Conclusions/Significance

The present study suggests that the tetra- and penta-acylated lipid A structures of P. gingivalis LPS differentially activate TLR4-mediated NF-κB signaling pathway, and significantly modulate the expression of IL-6 and IL-8 in HGFs. The ability to alter the lipid A structure of LPS could be one of the strategies carried-out by P. gingivalis to evade innate host defense in gingival tissues, thereby contributing to periodontal pathogenesis.

Expression profile of macrophage migration-inhibitory factor in human gingiva and reconstituted human gingival epithelia stimulated by Porphyromonas gingivalis lipopolysaccharide

BACKGROUND AND OBJECTIVE

Macrophage migration-inhibitory factor (MIF) plays crucial roles in the recruitment and activation of macrophages as well as in helping to kill bacteria. This study investigated the expression profile of MIF in human gingiva under different periodontal conditions and its expression patterns induced by Porphyromonas gingivalis lipopolysaccharide (LPS) in gingival epithelia.

MATERIAL AND METHODS

Gingival tissue samples were collected from deep pockets and clinically healthy sites of 22 nonsmoking subjects with chronic periodontitis. The expression of MIF mRNA and protein was evaluated using real-time PCR and immunohistochemistry, respectively. The in vitro study analyzed the effects of P. gingivalis LPS on the expression of MIF in a reconstituted human gingival epithelia (RHGE) model.

RESULTS

In gingival epithelia, MIF protein was diffusely expressed from the basal layer to the granular and spinous layers; whereas, in the underlying connective tissues, MIF was observed around the dilated blood vessels in the deep-pocket tissues. A significantly lower level of expression of MIF mRNA and an increased level of expression of MIF protein were found in deep-pocket tissues compared with clinically healthy tissues. Expression of MIF mRNA in the RHGE model was significantly down-regulated by P. gingivalis LPS.

CONCLUSION

The present study suggests that MIF expression may be related to periodontal conditions and that its expression profile could be modulated by P. gingivalis LPS. MIF may play a role in periodontal pathogenesis.

High-fat diet induces periodontitis in mice through lipopolysaccharides (LPS) receptor signaling: protective action of estrogens

Background

A fat-enriched diet favors the development of gram negative bacteria in the intestine which is linked to the occurrence of type 2 diabetes (T2D). Interestingly, some pathogenic gram negative bacteria are commonly associated with the development of periodontitis which, like T2D, is characterized by a chronic low-grade inflammation. Moreover, estrogens have been shown to regulate glucose homeostasis via an LPS receptor dependent immune-modulation. In this study, we evaluated whether diet-induced metabolic disease would favor the development of periodontitis in mice. In addition, the regulatory role of estrogens in this process was assessed.

Methods

Four-week-old C57BL6/J WT and CD14 (part of the TLR-4 machinery for LPS-recognition) knock-out female mice were ovariectomised and subcutaneously implanted with pellets releasing either placebo or 17β-estradiol (E2). Mice were then fed with either a normal chow or a high-fat diet for four weeks. The development of diabetes was monitored by an intraperitoneal glucose-tolerance test and plasma insulin concentration while periodontitis was assessed by identification of pathogens, quantification of periodontal soft tissue inflammation and alveolar bone loss.

Results

The fat-enriched diet increased the prevalence of periodontal pathogenic microbiota like Fusobacterium nucleatum and Prevotella intermedia, gingival inflammation and alveolar bone loss. E2 treatment prevented this effect and CD14 knock-out mice resisted high-fat diet-induced periodontal defects.

Conclusions/Significance

Our data show that mice fed with a diabetogenic diet developed defects and microflora of tooth supporting-tissues typically associated with periodontitis. Moreover, our results suggest a causal link between the activation of the LPS pathway on innate immunity by periodontal microbiota and HFD-induced periodontitis, a pathophysiological mechanism that could be targeted by estrogens.

Nuclear factor-κB and p38 mitogen-activated protein kinase signaling pathways are critically involved in Porphyromonas gingivalis lipopolysaccharide induction of lipopolysaccharide-binding protein expression in human oral keratinocytes

Lipopolysaccharide (LPS) -binding protein (LBP) plays a crucial role in innate host response to bacterial challenge. Porphyromonas gingivalis is a keystone pathogen in periodontal disease and the shift of P. gingivalis LPS lipid A structure from penta-acylated (LPS(1690)) to tetra-acylated (LPS(1435/1449)) isoform may significantly contribute to periodontal pathogenesis. We recently demonstrated that LBP is expressed in human gingiva and contributes to periodontal homeostasis. Furthermore, different isoforms of P. gingivalis LPS differently modulate the immuno-inflammatory response, and P. gingivalis LPS(1690) induces LBP expression in human oral keratinocytes (HOKs). This study further examined the signaling mechanisms of P. gingivalis LPS(1690) -induced and Escherichia coli LPS-induced LBP expression in HOKs. Both P. gingivalis LPS(1690) and E. coli LPS were potent inducers of LBP expression in HOKs. The former activated phosphorylation of IκBα, p65, p38 mitogen-activated protein kinase (MAPK) and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), whereas the latter phosphorylated IκBα, p38 MAPK and SAPK/JNK. A nuclear translocation of NF-κB transcription factor was confirmed upon stimulation by both forms of LPS. Further blocking assay showed that P. gingivalis LPS(1690) induction of LBP was through NF-κB and p38 MPAK pathways, whereas E. coli LPS-induced LBP expression was mediated by NF-κB, p38 MPAK and JNK pathways. This study demonstrates that NF-κB and p38 MAPK signaling pathways are involved in P. gingivalis LPS(1690) induction of LBP expression in HOKs. The current findings could enhance the understanding of the molecular mechanisms of innate defense in maintenance of periodontal homeostasis.

Bradykinin promotes Toll like receptor-4 expression in human gingival fibroblasts

Bacterial infections are a potent mechanism for enzymatic generation of kinins such as bradykinin (BK), a universal mediator for inducing inflammatory reaction by associating with the B2 receptor and stimulating liberation of arachidonic acid and synthesis of prostaglandin E2 (PGE2). In this study we evaluate the role of bradykinin in regulating the expression of TLR4 receptor in human gingival fibroblasts. We examine the ability of bradykinin to modulate inflammatory response of human gingival fibroblasts to Gram-negative components and evaluated the role of Toll-like receptors (TLR)-4 in the co-operation between bradykinin and bacterial pathogens. We show that treatment with bradykinin promotes TLR4 receptor expression in human gingival fibroblasts (HGF) and amplifies inflammatory responses to the bacterial components of Gram-negative bacteria. The TLR4 expression induced by bradykinin was blocked with Hoe 140, a B2R antagonist. When HGF cells were incubated with BK resulted of an increased in cyclooxygenase-2 (COX-2) expression and prostaglandin E2 synthesis. Bradykinin and lipopolysaccharide, a specific TLR4 ligand stimulated COX-2 expression. In other series of experiments we found that ERK, phosphatidylinositol-3 kinase, protein kinase C and NFkB are involved in BK promoted-increased in TLR4 expression. The results demonstrate that bradykinin up-regulates the expression of TLR4 and promotes an additive increase in inflammatory responses to lipopolysaccharides.

Postnatal development of hepatic innate immune response

The liver is an immunocompetent organ that plays a key role in the immune response to infections, and the development of hepatic immune function during early postnatal stages has not been thoroughly characterized. This study analyzed the constitutive expression of complement factors, namely C3 and C9, and pattern recognition receptors, namely CD14, toll-like receptor (TLR)-4, and lipopolysaccharide binding protein (LBP), in the liver of postnatal day (P)1, P21, and P70 rats, and compared the kinetics of induction of cytokines and chemokines in the liver of P 1 and P 21 animals. Our studies found that while the mRNA expression of C3, C9, CD14, and TLR-4 was lower in P1 animals, the mRNA level of LBP was higher in P1 animals as compared to older animals, and that the kinetics of induction of cytokines and chemokines was significantly delayed in P1 as compared to P21 liver following LPS stimulation. Our data suggest that hepatic innate immunity is deficient in the neonates and undergo significant development during early postnatal life.

Oral microbial biofilm stimulation of epithelial cell responses

Oral bacterial biofilms trigger chronic inflammatory responses in the host that can result in the tissue destructive events of periodontitis. However, the characteristics of the capacity of specific host cell types to respond to these biofilms remain ill-defined. This report describes the use of a novel model of bacterial biofilms to stimulate oral epithelial cells and profile select cytokines and chemokines that contribute to the local inflammatory environment in the periodontium. Monoinfection biofilms were developed with Streptococcus sanguinis, Streptococcus oralis, Streptococcus gordonii, Actinomyces naeslundii, Fusobacterium nucleatum, and Porphyromonas gingivalis on rigid gas-permeable contact lenses. Biofilms, as well as planktonic cultures of these same bacterial species, were incubated under anaerobic conditions with a human oral epithelial cell line, OKF4, for up to 24h. Gro-1α, IL1α, IL-6, IL-8, TGFα, Fractalkine, MIP-1α, and IP-10 were shown to be produced in response to a range of the planktonic or biofilm forms of these species. P. gingivalis biofilms significantly inhibited the production of all of these cytokines and chemokines, except MIP-1α. Generally, the biofilms of all species inhibited Gro-1α, TGFα, and Fractalkine production, while F. nucleatum biofilms stimulated significant increases in IL-1α, IL-6, IL-8, and IP-10. A. naeslundii biofilms induced elevated levels of IL-6, IL-8 and IP-10. The oral streptococcal species in biofilms or planktonic forms were poor stimulants for any of these mediators from the epithelial cells. The results of these studies demonstrate that oral bacteria in biofilms elicit a substantially different profile of responses compared to planktonic bacteria of the same species. Moreover, certain oral species are highly stimulatory when in biofilms and interact with host cell receptors to trigger pathways of responses that appear quite divergent from individual bacteria.

The Effect of Bleachıng Systems on the Gingiva and the Levels of IL-1β and IL-10 in Gingival Crevicular Fluid

Home and chemically activated bleaching systems could be considered safer in tooth whitening and maintaining gingival health when compared with a light-activated bleaching system.

The role of Desulfovibrio desulfuricans lipopolysaccharides in modulation of periodontal inflammation through stimulation of human gingival fibroblasts

OBJECTIVE

Periodontitis is a destructive disease which is likely to be the result of the activities of different microbial complexes. Recently, sulphate-reducing bacteria (SRB) have been detected in the oral cavity, and they have been found to be common inhabitants of sites showing periodontal destruction. The aim of study was to evaluate the influence of endotoxins of Desulfovibrio desulfuricans bacteria on human gingival fibroblast HGF-1 line.

METHODS

The immunological response of gingival fibroblasts was evaluated by determination of their IL-6 and IL-8 secretion upon treatment with D. desulfuricans intestinal and type strain LPS, sodium butyrate (NaB) and IL-1beta. The amounts of cytokines were estimated by ELISA immunoassay. The influence of LPS and NaB on fibroblast proliferation was determined using the CyQUANT Cell Proliferation Assay Kit.

RESULTS

No significant growth inhibition of cells exposed to LPS was observed, except for the culture growing in the presence of intestinal strain endotoxin at the highest concentration (100 microg/ml). The secretion of IL-6 and IL-8 by fibroblasts was increased by D. desulfuricans endotoxins. Cells stimulated with proinflammatory cytokine 1L-1beta showed very high levels of both cytokines secretion. The release of IL-6 and IL-8 by cells in response to LPS and 1L-1beta was modulated by butyric acid.

CONCLUSIONS

The observed response of gingival fibroblasts to stimulation by endotoxin suggests that D. desulfuricans can be involved in the pathogenesis of periodontitis. Moreover, butyrate present in the oral cavity seems to have immunoregulatory effect on cytokine production by gingival fibroblasts under physiological conditions and during microbe-induced inflammation.

Human gingiva is another site of C-reactive protein formation

OBJECTIVES

C-reactive protein (CRP) is primarily synthesized in the liver. It is hypothesized that human gingiva per se may produce CRP and its expression could be associated with IL-6. This study elucidated the CRP expression profile in human gingiva and its possible association with IL-6.

MATERIALS AND METHODS

Ninety-four gingival biopsies were collected from 44 subjects with chronic periodontitis and 18 periodontally healthy subjects. CRP protein was detected by immunohistochemistry and Western blotting, while CRP and IL-6 mRNAs were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR. CRP protein expression in the reconstituted human gingival epithelia (RHGE) was examined by the particle-enhanced immunoturbidimetric assay and Western blotting.

RESULTS

CRP protein was detected in gingival tissues from patients and healthy subjects by immunohistochemistry and confirmed by Western blotting. Its expression pattern and level at 16 pairs of periodontal pocket tissues and the adjacent clinically healthy tissues from 16 patients were significantly interrelated (r(s)=0.693, p<0.01). CRP mRNA expression was strongly correlated with IL-6 (r=0.694, p<0.001). Both CRP protein and mRNA were detected in the RHGE.

CONCLUSIONS

The present study shows for the first time that human gingiva is able to produce CRP in situ that may be associated with IL-6 activity.