In vivoexpression of Toll-like receptor 2, Toll-like receptor 4, CSF2 and LY64 in Chinese chronic periodontitis patients

Toll-like receptor 4 deficiency affects the balance of osteoclastogenesis and osteoblastogenesis in periodontitis

Toll-like receptor 4 (TLR4) acts as a double-edged sword in the occurrence and development of periodontitis. While the activation of TLR4 in macrophages aids in clearing local pathogens, it can also disrupt innate immune responses, upsetting microecological balance and accelerating the destruction of periodontal bone tissues. To date, the effects of TLR4 on osteogenesis and osteoclastogenesis in periodontitis have not been comprehensively studied. In this study, we investigated the development of periodontitis in the Tlr4-/- mice by ligating their second molars with silk threads. Compared to wild-type (WT) mice, Tlr4-/- mice demonstrated increased resistance to periodontitis-associated bone destruction, as evidenced by decreased bone resorption and enhanced bone regeneration. Mechanistically, the deletion of Tlr4 not only inhibited osteoclast formation by reducing the expression of NFATc1, CTSK and TRAP, but also enhanced osteogenic abilities through increased expression of OCN, OPN and RUNX2. In conclusion, TLR4 tips the balance of osteoclastogenesis and osteogenesis, thereby promoting periodontal bone destruction in periodontitis.

Oxidative Stress Inhibits Endotoxin Tolerance and May Affect Periodontitis

Periodontal disease is caused by dysbiosis of the dental biofilm and the host inflammatory response. Various pathogenic factors, such as proteases and lipopolysaccharides (LPSs) produced by bacteria, are involved in disease progression. Endotoxin tolerance is a function of myeloid cells, which sustain inflammation and promote tissue regeneration upon prolonged stimulation by endotoxins such as LPS. The role of endotoxin tolerance is gaining attention in various chronic inflammatory diseases, but its role in periodontal disease remains elusive. Oxidative stress, one of the major risk factors for periodontal disease, promotes disease progression through various mechanisms, of which only some are known. The effect of oxidative stress on endotoxin tolerance has not yet been studied, and we postulated that endotoxin tolerance regulation may be an additional mechanism through which oxidative stress influences periodontal disease. This study aimed to reveal the effect of oxidative stress on endotoxin tolerance and that of endotoxin tolerance on periodontitis progression. The effect of oxidative stress on endotoxin tolerance was analyzed in vitro using peritoneal macrophages of mice and hydrogen peroxide (H₂O₂). The results showed that oxidative stress inhibits endotoxin tolerance induced by Porphyromonas gingivalis LPS in macrophages, at least partially, by downregulating LPS-elicited negative regulators of Toll-like receptor (TLR) signaling. A novel oxidative stress mouse model was established using SMP30KO mice incapable of ascorbate biosynthesis. Using this model, we revealed that oxidative stress impairs endotoxin tolerance potential in macrophages in vivo. Furthermore, gingival expression of endotoxin tolerance-related genes and TLR signaling negative regulators was decreased, and symptoms of ligature-induced periodontitis were aggravated in the oxidative stress mouse model. Our findings suggest that oxidative stress may contribute to periodontitis progression through endotoxin tolerance inhibition.

Association between periodontitis and peripheral markers of innate immunity activation and inflammation

BACKGROUND

Immune response leading to increased systemic inflammation is one of the mechanisms linking periodontitis to chronic inflammatory diseases. The aim of this study was to compare the expression of toll-like receptors 2 and 4 in monocytes and neutrophils (TLR2M, TLR2N, TLR4M, and TLR4N) and its endogenous ligands (cellular fibronectin [cFN] and heat shock protein 60 [HSP60]) in patients with and without periodontitis. Additionally, the relationship between cFN and HSP60 expression with innate immunity activation and systemic inflammatory response (interleukin 6 [IL-6]) was also evaluated.

METHODS

A case-controlled study was designed in which 30 patients with periodontitis (cases) and 30 age- and sex-matched participants without periodontitis (controls) were included. Fasting blood samples were collected to determine: (1) expression of TLR2N, TLR2M, TLR4N, and TLR4M by flow cytometry; and (2) serum concentrations of cFN, HSP60, and IL-6 by ELISA technique.

RESULTS

Expression of TLR2M (411.5 [314.2, 460.0] vs. 236.5 [204.0, 333.0] AFU), TLR2N (387.0 [332.0, 545.5] vs 230.0 [166.2, 277.7] AFU), TLR4M (2478.5 [1762.2, 2828.0] vs 1705.0 [1274.5, 1951.2] AFU), and TLR4N (2791.0 [2306.7, 3226.2] vs. 1866.0 [1547.5, 2687.2] AFU) as well as serum levels of cFN (301.1 [222.2, 410.9] vs. 156.4 [115.3, 194.0] ng/ml) and IL-6 (10.4 [6.5, 11.5] vs. 3.5 [2.6, 4.9] pg/ml) were significantly higher in periodontitis patients than those without periodontitis. A positive association was found between periodontitis and cFN (odds ratio [OR] = 1.028, p < 0.001), TLR2N (OR = 1.026, p < 0.001), TLR4M (OR = 1.001, p = 0.002), and IL-6 (OR = 1.774, p < 0.001).

CONCLUSIONS

Periodontitis patients exhibited high expression of TLRs, cFN, and IL-6.

Crosstalk between Venous Thromboembolism and Periodontal Diseases: A Bioinformatics Analysis

Background

This current study applied bioinformatics analysis to reveal the crosstalk between venous thromboembolism (VTE) and periodontitis, as well as the potential role of immune-related genes in this context.

Methods

Expression data were downloaded from the GEO database. Blood samples from venous thromboembolism (VTE) were used (GSE19151), while for periodontal disease, we used gingival tissue samples (GSE10334, GSE16134, and GSE23586). After batch correction, we used “limma” packages of R language for differential expression analysis (p value < 0.05, ∣logFC | ≥0.5). We used Venn diagrams to extract the differentially expressed genes common to VTE and periodontitis as potential crosstalk genes and applied functional enrichment analysis (GO biological process and KEGG pathway). The protein-protein interaction (PPI) network of crosstalk genes was constructed by Cytoscape software. The immune-related genes were downloaded from the literature. The Wilcoxon test was used to test the scores of immune infiltrating cells. The crosstalk genes were further screened by LASSO Logistic Regression.

Results

For periodontitis, 427 case and 136 control samples, and for VTE, 70 case and 63 control samples were included. The obtained PPI network had 1879 nodes and 2257 edges. Moreover, 782 immune genes and 28 cell types were included in the analysis. Over 90% of immune cells had different expressions in VTE and periodontitis. We obtained 12 significant pathways corresponding to crosstalk genes. CD3D, CSF3R, and CXCR4 acted as an immune gene and a crosstalk gene. We obtained a total of 12 shared biomarker crosstalk genes. Among those 12 biomarker crosstalk genes, 4 were immune genes (LGALS1, LSP1, SAMSN1, and WIPF1).

Conclusion

Four biomarker crosstalk genes between periodontitis and VTE were also immune genes, i.e., LGALS1, LSP1, SAMSN1, and WIPF1. The findings of the current study need further validation and are a basis for development of biomarkers.

Transcription Factor EepR Is Required for Serratia marcescens Host Proinflammatory Response by Corneal Epithelial Cells

Relatively little is known about how the corneal epithelium responds to vision-threatening bacteria from the Enterobacterales order. This study investigates the impact of Serratia marcescens on corneal epithelial cell host responses. We also investigate the role of a bacterial transcription factor EepR, which is a positive regulator of S. marcescens secretion of cytotoxic proteases and a hemolytic surfactant. We treated transcriptomic and metabolomic analysis of human corneal limbal epithelial cells with wild-type bacterial secretomes. Our results show increased expression of proinflammatory and lipid signaling molecules, while this is greatly altered in eepR mutant-treated corneal cells. Together, these data support the model that the S. marcescens transcription factor EepR is a key regulator of host-pathogen interactions, and is necessary to induce proinflammatory chemokines, cytokines, and lipids.

Autophagy and its significance in periodontal disease

Autophagy is an evolutionarily conserved process essential for cellular homeostasis and human health. As a lysosome-dependent degradation pathway, autophagy acts as a modulator of the pathogenesis of diverse diseases. The relationship between autophagy and oral diseases has been explored in recent years, and there is increasing interest in the role of autophagy in periodontal disease. Periodontal disease is a prevalent chronic inflammatory disorder characterized by the destruction of periodontal tissues. It is initiated through pathogenic bacterial infection and interacts with the host immune defense, leading to inflammation and alveolar bone resorption. In this review, we outline the machinery of autophagy and present an overview of work on the significance of autophagy in regulating pathogen invasion, the immune response, inflammation, and alveolar bone homeostasis of periodontal disease. Existing data provide support for the importance of autophagy as a multi-dimensional regulator in the pathogenesis of periodontal disease and demonstrate the importance of future research on the potential roles of autophagy in periodontal disease.

Dysregulation of genes and microRNAs in localized aggressive periodontitis

AIM

Previous data from our laboratory have demonstrated that localized aggressive periodontitis (LAP) patients produce elevated levels of pro-inflammatory cytokines in response to TLR4 and TLR2 ligation compared to unrelated and periodontally healthy controls (HC). The aim of the present work is to evaluate the contribution of TLR-related gene expression and miRNA regulation in LAP disease.

MATERIAL AND METHODS

Peripheral blood mononuclear cells (PBMCs) from LAP and health control (HC) patients were isolated. Gene and miRNA expression involved in TLR signalling pathway and immunopathology were evaluated in unstimulated PBMCs by real-time PCR (RT-PCR).

RESULTS

TICAM-1 (TRIF), FOS, IRAK1, TLR2 and CCL2 genes and the miRNAs miR-9-5p, miR-155-5p and 203a-3p, miR-147a, miR-182-5p and miR-183-5p were significantly up-regulated in LAP compared to HC.

CONCLUSIONS

Most of the genes and miRNAs overexpressed here are directly or indirectly related to immune response and inflammation. This profile supports our previous findings that suggests LAP patients have a "hyper-responsive" phenotype upon activation of TLR pathway by periodontal pathogens.

Gene expression profile analysis of ileum transcriptomes in pigs fed Gelsemium elegans plants

Gelsemium elegans is a flowering plant in the Loganiaceae. Because it can promote the growth of pigs and sheep, it is widely used, including in veterinary clinics, but little information is available about its biological effects. Here, we used high-throughput sequencing to characterize the differentially expressed genes (DEGs) in the ileums of pigs between a control group and a group fed Gelsemium elegans for 45 days. We found that Gelsemium elegans affected many inflammatory and immune pathways, including biological processes such as defense responses, inflammation and immune responses. Moreover, this study identified several important genes related to the anti-inflammatory activity of Gelsemium elegans (e.g., CXCL-8, IL1A, and CSF2), which will be beneficial for further study of the pharmacological mechanisms and clinical applications of Gelsemium elegans.

Biofilm-induced profiles of immune response gene expression by oral epithelial cells

This study examined the oral epithelial immunotranscriptome response patterns modulated by oral bacterial planktonic or biofilm challenge. We assessed gene expression patterns when epithelial cells were challenged with a multispecies biofilm composed of Streptococcus gordonii, Fusobacterium nucleatum, and Porphyromonas gingivalis representing a type of periodontopathic biofilm compared to challenge with the same species of planktonic bacteria. Of the 579 human immunology genes, a substantial signal of the epithelial cells was observed to 181 genes. Biofilm challenged stimulated significant elevations compared to planktonic bacteria for IL32, IL8, CD44, B2M, TGFBI, NFKBIA, IL1B, CD59, IL1A, CCL20 representing the top 10 signals comprising 55% of the overall signal for the epithelial cell responses. Levels of PLAU, CD9, IFITM1, PLAUR, CD24, TNFSF10, and IL1RN were all elevated by each of the planktonic bacterial challenge vs the biofilm responses. While the biofilms up-regulated 123/579 genes (>2-fold), fewer genes were increased by the planktonic species (36 [S gordonii], 30 [F nucleatum], 44 [P gingivalis]). A wide array of immune genes were regulated by oral bacterial challenge of epithelial cells that would be linked to the local activity of innate and adaptive immune response components in the gingival tissues. Incorporating bacterial species into a structured biofilm dramatically altered the number and level of genes expressed. Additionally, a specific set of genes were significantly decreased with the multispecies biofilms suggesting that some epithelial cell biologic pathways are down-regulated when in contact with this type of pathogenic biofilm.

The role of toll-like and protease-activated receptors and associated intracellular signaling in Porphyromonas gingivalis-infected gingival fibroblasts

Porphyromonas gingivalis, which is considered a keystone agent in periodontitis, has evolved elaborate mechanisms to grow and survive in a hostile milieu. The gingival fibroblast is the major cell type in the gingiva and is considered to be important in the periodontitis-associated inflammation. As a part of the innate immune response, they produce cytokines such as CXCL8 and interleukin (IL)-6 which are believed to contribute to the destruction of the tooth-supporting tissues. This study investigates how the expression of protease-activated receptors (PAR1, PAR2) and toll-like receptors (TLR2, TLR4) changes with P. gingivalis exposure and how silencing of one receptor affects the expression of the other receptors. The importance of protein kinase C (PKC) and p38 in the regulation of CXCL8 and IL-6 was also examined. Receptors were knockdown with small-interfering RNA. PKC or p38 was blocked prior to stimulation with P. gingivalis. Fibroblasts were able to compensate for PAR1 knockdown with increased expression of PAR2. PKC and p38 were involved in the regulation of P. gingivalis-induced CXCL8 and IL-6. Our results indicate that PAR1 and PAR2 could be implicated in periodontitis and that PKC and P38 play a role in the inflammatory response in P. gingivalis-infected gingival fibroblasts.

Evaluation of the gingival inflammation in pregnancy and postpartum via 25-hydroxy-vitamin D3, prostaglandin E2 and TNF-α levels in saliva

BACKGROUND

Physiological changes and immunological modifications occur during pregnancy. The clinical and biological features of periodontal infections are affected by pregnancy. The aim of the present study was to evaluate saliva levels of 25-hydroxy-vitamin D3 (25(OH)D3), prostaglandin E2 (PGE2) and TNF-alpha (TNF-α) in pregnancy, postpartum and non-pregnant controls.

METHODS

Whole saliva samples together with full-mouth clinical periodontal recordings were obtained from 59 pregnant, 47 post partum and 70 systemically healthy non-pregnant women. Groups were also evaluated according to the periodontal health status. 25(OH)D3, PGE2 and TNF-α levels in the saliva samples were determined by enzyme-linked immunoassays. Data were statistically tested by nonparametrical tests.

RESULTS

Saliva TNF-α and PGE2 levels were significantly lower and 25(OH)D3 levels were significantly higher in the pregnant group than postpartum group (p<0.0001). Saliva TNF-α and 25(OH)D3 levels were significantly higher and PGE2 levels were significantly lower in the control group than postpartum group (p<0.0001). In the pregnant healthy, gingivitis and periodontitis groups saliva TNF-α levels were significantly lower than postpartum and control counterparts (p<0.0001, p=0.032, p=0.003 and p=0.013; p=0.027; p=0.007, respectively). In control healthy, gingivitis and periodontitis groups saliva 25(OH)D3 levels were significantly higher than the postpartum counterparts (p<0.0001, p<0.0001, p=0.002, respectively). In the control healthy and gingivitis groups saliva 25(OH)D3 levels were significantly higher than pregnant healthy and gingivitis (p<0.0001).

CONCLUSIONS

In conclusion, within the limits of the present study it seems that pregnancy have an effect on parameters in saliva in relation to the periodontal status of the women. Further studies are required for better understanding of the impact of periodontal diseases on pregnancy or otherwise.

Oxidative stress markers in saliva and periodontal disease status: modulation during pregnancy and postpartum

BACKGROUND

Periodontal diseases may affect local and systemic inflammation, and reactive oxygen species (ROS) levels. This systemic health burden could compromise the outcome of pregnancy in expectant mothers. The aim of the present study was to evaluate oxidative stress markers, including glutathione peroxidase (GPx), thiobarbituric acid-reactive substances (TBARS) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), and total bacterial loads in the saliva of pregnant and postpartum women, and to investigate their association with periodontal disease severity.

METHODS

A total of 187 women were originally recruited for this case-control study, assigned to the following groups a) pregnant group, b) postpartum group: the pregnant group re-evaluated 6 months after giving birth, c) control group: systemically healthy and non-pregnant women. The levels of the studied oxidative stress markers in saliva were measured by commercially available kits.

RESULTS

The levels of salivary 8-OHdG were significantly elevated in the pregnant, compared with the control group. Although salivary 8-OHdG levels slightly decreased after giving birth (postpartum group), the difference did not reach significance. In contrast, the activity of antioxidant enzyme GPx in saliva was significantly lower in the pregnant than the control group. Although no differences in lipid peroxidation (represented by TBARS) were observed between the pregnant and control groups, after giving birth TBARS levels were significantly lowered. Only in the postpartum and control groups did clinical measurements of periodontal disease severity correlate with oxidative stress markers. Interestingly, there were no such correlations with TBARS in the pregnant and postpartum groups.

CONCLUSIONS

The present study shows changes in the oxidant/antioxidant balance in saliva during pregnancy and after birth, which may be affected by periodontal health status in the latter case. Whether this is associated with adverse pregnancy outcomes, or not, remains to be elucidated. Early identification of ROS markers in saliva may be of clinical value in the periodontal management of pregnant women.

Evaluation of biochemical parameters and local and systemic levels of osteoactive and B-cell stimulatory factors in gestational diabetes in the presence or absence of gingivitis

BACKGROUND

Gestational diabetes mellitus (GDM) is defined as varying glucose intolerance, with first onset or recognition in pregnancy. This study evaluates clinical and biochemical parameters in a possible association between GDM and gingivitis.

METHODS

A total of 167 pregnant females was included in the study. There were 101 females with GDM and 66 females without GDM. Subgroups were created according to the presence or absence of gingival inflammation. Plaque index, bleeding on probing, and probing depth were recorded at four sites per tooth. Serum, saliva, and gingival crevicular fluid (GCF) levels of interleukin (IL)-6, IL-8, soluble receptor activator of nuclear factor-kappa B ligand (sRANKL), osteoprotegerin (OPG), B-cell activating factor (BAFF), and a proliferation-inducing ligand (APRIL) were determined by enzyme-linked immunosorbent assay. Data were analyzed by Kruskal-Wallis and Mann-Whitney U tests and Spearman correlation analysis.

RESULTS

Age and anthropometric indices were higher in the GDM than non-GDM group (P <0.0001). Clinical periodontal recordings, serum BAFF, IL-8, and saliva sRANKL levels were higher in the GDM group (P <0.05). Saliva IL-6 level was higher in the GDM with gingivitis group than non-GDM with gingivitis group (P = 0.044). Serum and GCF BAFF (P <0.0001), serum, saliva, and GCF APRIL (P <0.0001; P <0.0001; P = 0.032, respectively), GCF OPG (P = 0.036), and serum and saliva sRANKL (P <0.0001) were higher in the GDM with gingivitis group than GDM without gingivitis group.

CONCLUSIONS

The inflammatory response seems to be more pronounced in females with GDM. The observed increase in both local and systemic levels of inflammatory cytokines may suggest an interaction between gingivitis and GDM.

Differential expression of Toll-like receptor 4 in healthy and diseased human gingiva

BACKGROUND AND OBJECTIVE

Lipopolysaccharide (LPS)-mediated signaling in host cells involves Toll-like receptor 4 (TLR4) accessory molecules, including LPS-binding protein (LBP), cluster of differentiation 14 (CD14) and lymphocyte antigen 96 (MD-2). However, expression of these innate defense molecules in various compartments of the human periodontium is unclear. The aim of this study was to investigate the expression profile of TLR4 in human gingiva.

MATERIAL AND METHODS

Human gingival biopsies were collected from healthy gingival or chronic periodontitis tissue. Primary gingival keratinocytes and fibroblasts were cultured. Immunohistochemical analysis for TLR4 was performed. Transcripts of TLR4, MD-2, CD14 and LBP, and their protein products, were examined using RT-PCR, immunoprecipitation and immunoblotting. The interactions between these molecules in keratinocytes and fibroblasts were investigated by co-immunoprecipitation.

RESULTS

TLR4 immunoreactivity was found in healthy gingival epithelium and periodontitis tissue, and appeared to be lower in junctional epithelium ( p ≤ 0.01). Fibroblasts and inflammatory cells stained more strongly for TLR4 in diseased periodontal tissues (p < 0.001). Three TLR4 splicing variants, two MD-2 splicing variants and one CD14 mRNA were expressed by gingival keratinocytes and fibroblasts. Expression of TLR4, CD14 and MD-2 proteins was detected in keratinocytes and fibroblasts in vitro. TLR4 protein from gingival keratinocytes and fibroblasts could be co-immunoprecipitated with CD14 or MD-2, suggesting an association between the related molecules in vivo. LBP transcript was detected in gingival biopsies, but not in primary cultures of gingival keratinocytes or fibroblasts.

CONCLUSION

TLR4, CD14 and MD-2, but not LBP, are expressed in human gingival keratinocytes and fibroblasts. The TLR4 expression level in the junctional epithelium appeared to be lowest within the periodontal epithelial barrier.

Microarray analysis of gene expression alteration in human middle ear epithelial cells induced by micro particle

OBJECTIVES

The primary aim of this study is to reveal the effect of particulate matter (PM) on the human middle ear epithelial cell (HMEEC).

METHODS

The HMEEC was treated with PM (300 μg/ml) for 24 h. Total RNA was extracted and used for microarray analysis. Molecular pathways among differentially expressed genes were further analyzed by using Pathway Studio 9.0 software. For selected genes, the changes in gene expression were confirmed by real-time PCR.

RESULTS

A total of 611 genes were regulated by PM. Among them, 366 genes were up-regulated, whereas 245 genes were down-regulated. Up-regulated genes were mainly involved in cellular processes, including reactive oxygen species generation, cell proliferation, apoptosis, cell differentiation, inflammatory response and immune response. Down-regulated genes affected several cellular processes, including cell differentiation, cell cycle, proliferation, apoptosis and cell migration. A total of 21 genes were discovered as crucial components in potential signaling networks containing 2-fold up regulated genes. Four genes, VEGFA, IL1B, CSF2 and HMOX1 were revealed as key mediator genes among the up-regulated genes. A total of 25 genes were revealed as key modulators in the signaling pathway associated with 2-fold down regulated genes. Four genes, including IGF1R, TIMP1, IL6 and FN1, were identified as the main modulator genes.

CONCLUSIONS

We identified the differentially expressed genes in PM-treated HMEEC, whose expression profile may provide a useful clue for the understanding of environmental pathophysiology of otitis media. Our work indicates that air pollution, like PM, plays an important role in the pathogenesis of otitis media.

Saliva and serum levels of B-cell activating factors and tumor necrosis factor-α in patients with periodontitis

BACKGROUND

B-lymphocytes play a central and critical role in the adaptive immune response against invading pathogens. This study evaluates saliva and serum levels of APRIL (a proliferation-inducing ligand), B-cell activating factor (BAFF), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-10 in patients with chronic periodontitis (CP) or aggressive periodontitis (AgP) and periodontally healthy individuals.

METHODS

Twenty-five patients with AgP, 20 patients with CP, and 20 periodontally healthy individuals were included. Smoking status was recorded, and all individuals were divided into non-smokers and smokers. Saliva and serum samples were collected before clinical periodontal measurements. APRIL, BAFF, TNF-α, IL-6, and IL-10 levels in serum and saliva samples were determined by enzyme-linked immunosorbent assay. Statistical analysis was performed using multivariate analysis of variance and bivariate correlation.

RESULTS

Serum and saliva levels of TNF-α, APRIL, BAFF, IL-6, and IL-10 were similar in CP and AgP groups. Serum levels of TNF-α, APRIL, and BAFF and saliva levels of BAFF were significantly higher in periodontitis groups than healthy controls (P <0.05). Non-smokers with CP or AgP had lower levels of saliva TNF-α and APRIL and serum APRIL and IL-6 than smokers with CP or AgP (P <0.05). Saliva APRIL and serum TNF-α and IL-6 levels were significantly higher in healthy smokers than healthy non-smokers (P <0.05). Clinical periodontal parameters correlated positively with TNF-family cytokines and negatively with IL-10 (P <0.05).

CONCLUSIONS

Within the limits of this study, it may be suggested that elevated salivary and serum TNF-α, APRIL, and BAFF in patients with periodontitis may contribute to the dominance of B cells in periodontitis lesions. Moreover, higher levels in healthy smokers than non-smoking counterparts may play a role in detrimental effects of smoking on periodontal tissues.

Effects of aging on endotoxin tolerance induced by lipopolysaccharides derived from Porphyromonas gingivalis and Escherichia coli

BACKGROUND

Periodontitis is a bacterially induced chronic inflammatory disease. Exposure of the host to periodontal pathogens and their virulence factors induces a state of hyporesponsiveness to subsequent stimulations, termed endotoxin tolerance. Aging has a profound effect on immune response to bacteria challenge. The aim of this study was to explore the effects of aging on endotoxin tolerance induced by Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS) and Escherichia coli (E. coli) LPS in murine peritoneal macrophages.

METHODOLOGY/PRINCIPAL FINDINGS

We studied the cytokine production (TNF-α and IL-10) and Toll-like receptor 2, 4 (TLR2, 4) gene and protein expressions in peritoneal macrophages from young (2-month-old) and middle-aged (12-month-old) ICR mice following single or repeated P. gingivalis LPS or E. coli LPS stimulation. Pretreatment of peritoneal macrophages with P. gingivalis LPS or E. coli LPS resulted in a reduction in TNF-α production and an increase in IL-10 production upon secondary stimulation (p<0.05), and the markedly lower levels of TNF-α and higher levels of IL-10 were observed in macrophages from young mice compared with those from middle-aged mice (p<0.05). In addition, LPS restimulations also led to the significantly lower expression levels of TLR2, 4 mRNA and protein in macrophages from young mice (p<0.05).

CONCLUSIONS/SIGNIFICANCE

Repeated LPS stimulations triggered endotoxin tolerance in peritoneal macrophages and the ability to develop tolerance in young mice was more excellent. The impaired ability to develop endotoxin tolerance resulted from aging might be related to TLR2, 4 and might lead to the incontrollable periodontal inflammation in older adults.

Salivary and plasma levels of Toll-like receptor 2 and Toll-like receptor 4 in chronic periodontitis

BACKGROUND

This cross-sectional study was planned to investigate whether patients with chronic periodontitis exhibit different salivary or plasma concentrations of Toll-like receptor (TLR) 2 and TLR4 compared to subjects who are clinically healthy.

METHODS

Whole saliva and plasma samples were obtained and full-mouth clinical periodontal measurements were recorded from 22 otherwise healthy patients with chronic periodontitis and 21 systemically and periodontally healthy control subjects. Salivary and plasma TLR2 and TLR4 levels were determined by enzyme-linked immunoassays. Data were tested statistically using Mann-Whitney U test.

RESULTS

The healthy group exhibited significantly lower values in all clinical measurements (P <0.001). The salivary TLR2 levels were similar in the two study groups (P >0.05). The patients with chronic periodontitis exhibited significantly higher salivary TLR4 (P <0.01) and plasma TLR2 and TLR4 levels (P <0.05).

CONCLUSION

The present findings support a hypothesis that inflammation increases expression of TLRs which leads to an increased detection of TLRs in saliva and plasma, which could be useful as a diagnostic test for periodontal diseases.