Increased interleukin-1 beta (IL-1 beta) concentration in gingival tissue from periodontitis patients

TRPV4 mediates IL-1-induced Ca2+ signaling, ERK activation and MMP expression

Ca2+ permeation through TRPV4 in fibroblasts is associated with pathological matrix degradation. In human gingival fibroblasts, IL-1β binding to its signaling receptor (IL-1R1) induces activation of extracellular regulated kinase (ERK) and MMP1 expression, processes that require Ca2+ flux across the plasma membrane. It is not known how IL-1R1, which does not conduct Ca2+, generates Ca2+ signals in response to IL-1. We examined whether TRPV4 mediates the Ca2+ fluxes required for ERK signaling in IL-1 stimulated gingival fibroblasts. TRPV4 was immunostained in fibroblasts of human gingival connective tissue and in focal adhesions of cultured mouse gingival fibroblasts. Human gingival fibroblasts treated with IL-1β showed no change of TRPV4 expression but there was increased MMP1 expression. In mouse, gingival fibroblasts expressing TRPV4, IL-1 strongly increased [Ca2+]i. Pre-incubation of cells with IL-1 Receptor Antagonist blocked Ca2+ entry induced by IL-1 or the TRPV4 agonist GSK101. Knockout of TRPV4 or expression of a non-Ca2+-conducting TRPV4 pore-mutant or pre-incubation with the TRPV4 inhibitor RN1734, blocked IL-1-induced Ca2+ transients and expression of the mouse interstitial collagenase, MMP13. Treatment of mouse gingival fibroblasts with GSK101 phenocopied Ca2+ and ERK responses induced by IL-1; these responses were absent in TRPV4-null cells or cells expressing a non-conducting TRPV4 pore-mutant. Immunostained IL-1R1 localized with TRPV4 in adhesions within cell extensions. While TRPV4 immunoprecipitates analyzed by mass spectrometry showed no association with IL-1R1, TRPV4 associated with Src-related proteins and Src co-immunoprecipitated with TRPV4. Src inhibition reduced IL-1-induced Ca2+ responses. The functional linkage of TRPV4 with IL-1R1 expands its repertoire of innate immune signaling processes by mediating IL-1-driven Ca2+ responses that drive matrix remodeling in fibroblasts. Thus, inhibiting TRPV4 activity may provide a new pharmacological approach for blunting matrix degradation in inflammatory diseases.

The impact of electronic cigarettes on peri-implant health: A systematic review and meta-analysis

OBJECTIVES

Recent literature suggests that the use of electronic cigarette (e-cigarette) is a substantial contributing factor to the unsuccessful outcomes of dental implant procedures. Our aim was to systematically review the effect of e-cigarette use on clinical (PI, PD, BOP), radiographic (bone loss), and immunologic (IL-1β) peri‑implant parameters.

DATA

Main search terms used in combination: electronic cigarette, peri‑implantitis, vaping.

SOURCES

An electronic search was undertaken for MEDLINE, EMBASE, COCHRANE, and SCOPUS databases between 2017 and 2023.

STUDY SELECTION

The study protocol was developed according to PRISMA guidelines, and the focus question was formulated according to the PICO strategy. No restriction was accepted regarding language or year to avoid selection bias; the initial database search yielded 49 publications. Following the selection process, only seven studies met the inclusion criteria. Seven studies were statistically analyzed via MedCalc program. A pooled effect was deemed statistically significant if the p-value was less than 0.05.

CONCLUSION

Electronic cigarettes cause an increase in probing depth, bone loss, and the level of IL-1β, one of the bone destruction mediators in the tissues around the implant, and a decrease in bleeding on probing.

CLINICAL SIGNIFICANCE

E-cigarette is a potential risk factor for the healing process and the results of implant treatment, similar to cigarettes. Performing clinical research to evaluate the e-cigarette effect on peri‑implantitis in an age and gender-match population is needed.

Analysis of Salivary Levels of IL-1β, IL17A, OPG and RANK-L in Periodontitis Using the 2017 Classification of Periodontal Diseases-An Exploratory Observational Study

Periodontitis is a chronic disease with a high overall prevalence. It involves a complex interplay between the immune-inflammatory pathways and biofilm changes, leading to periodontal attachment loss. The aims of this study were (i) to assess whether the salivary IL-1β, IL-17A, RANK-L and OPG levels have the potential to discriminate between the mild and severe periodontitis conditions; and (ii) to enable diagnostic/prognostic actions to differentiate between distinct levels of the disease. The analysis of the clinical parameters and the evaluation of the salivary immunomediators levels by means of a multiplex flow assay revealed a statistically significantly higher level of IL-1β in the periodontitis III/IV patients, as well as a higher level of RANK-L in the periodontitis III/IV and I/II patients, when compared to the healthy controls. Furthermore, the grade C periodontitis patients presented a significantly higher level of RANK-L compared to the grade B and grade A patients. In the grade C patients, IL-1β had a positive correlation with the PPD and CAL indices and RANK_L had a positive correlation with CAL. The evidence emerging from this study associates the salivary IL-1β and RANK-L levels with an advanced stage of periodontitis, stage III/IV, and with grade C, suggesting the possible cooperative action of both in the inflammatory and bone loss events. In addition to IL-1β, RANK-L could be considered a combined diagnostic biomarker for periodontitis.

In vitro and in vivo study of the pathogenic role of PPARα in experimental periodontitis

OBJECTIVE

The purpose of this study is to investigate the pathogenic role of PPARα in periodontal antigen treated gingival cells in vitro and in experimental periodontitis in vivo .

METHODOLOGY

Gingival fibroblasts, gingival epithelial cells and splenocytes were isolated from C57BL/6J wild type (WT) mice and treated with fixed P. gingivalis at for 48 hours. The mRNA levels of PPARs, TNFα, IL-1β and IL-10 were detected by Real-time quantitative PCR. Silk ligatures after being soaked in the P.gingivalis suspension were tied around both maxillary second molars of WT mice or PPARα knock-out (KO) mice for two weeks. PPARα agonist fenofibrate and vehicle control were injected into the different side of the palatal gingiva on days 3, 6, and 9. At day 14, bone resorption and gingival mRNA expression levels of PPARs, TNFα, IL-1β and IL-10 were measured by micro-computed tomography and RT-qPCR respectively.

RESULTS

P. gingivalis treatment downregulated the expression of PPARα, but not PPARβ or PPARγ, and increased the expression of TNF-α and IL-1β in Gingival fibroblasts, gingival epithelial cells and splenocytes from WT mice. Gingival mRNA levels of PPARα were significantly decreased in experimental periodontitis in WT mice. The bone loss of PPARα KO mice in experimental periodontitis was significantly higher than WT mice and was not reduced by fenofibrate treatment. Gingival TNFα protein expressions were significantly increased by P. gingivalis associated ligation and decreased by fenofibrate treatment in WT mice but not in PPARα KO mice.

CONCLUSION

This study suggests that PPARα plays an essential role in periodontitis.

The Leucine-Rich Repeat Region of CARMIL1 Regulates IL-1-Mediated ERK Activation, MMP Expression, and Collagen Degradation

CARMILs are large, multidomain, membrane-associated proteins that regulate actin assembly and Rho-family GTPases, but their role in inflammatory signaling is not defined. Tandem mass tag mass spectrometry indicated that, in fibroblasts, CARMIL1 associates with interleukin (IL)-1 signaling molecules. Immunoprecipitation of cells transfected with CARMIL1 mutants showed that the leucine-rich repeat (LRR) region of CARMIL1 associates with IL-1 receptor type 1 (IL-1R1) and IL-1 receptor-associated kinase (IRAK). Knockout of CARMIL1 by CRISPR-Cas9 reduced IL-1-induced ERK activation by 72% and MMP3 expression by 40%. Compared with CARMIL1 wild-type (WT), cells expressing mutant CARMIL1 lacking its LRR domain exhibited 45% lower ERK activation and 40% lower MMP3 expression. In fibroblasts transduced with a cell-permeable, TAT CARMIL1 peptide that competed with IL-1R1 and IRAK binding to the LRR of CARMIL1, collagen degradation was reduced by 43%. As the LRR of CARMIL1 evidently regulates IL-1 signaling, CARMIL1 could become a target for anti-inflammatory drug development.

Regulation of ghrelin receptor by microbial and inflammatory signals in human osteoblasts

Recently, it has been suggested that the anti-inflammatory hormone ghrelin (GHRL) and its receptor GHS-R may play a pivotal role in periodontal health and diseases. However, their exact regulation and effects in periodontitis are not known. The aim of this in-vitro study was to investigate the effect of microbial and inflammatory insults on the GHS-R1a expression in human osteoblast-like cells. MG-63 cells were exposed to interleukin (IL)-1β and Fusobacterium nucleatum in the presence and absence of GHRL for up to 2 d. Subsequently, gene expressions of GHS-R1a, inflammatory mediators and matrix metalloproteinase were analyzed by real-time PCR. GHS-R protein synthesis and NF-κB p65 nuclear translocation were assessed by immunocytochemistry and immunofluorescence microscopy, respectively. IL-1β and F. nucleatum caused a significant upregulation of GHS-R1a expression and an increase in GHS-R1a protein. Pre-incubation with a MEK1/2 inhibitor diminished the IL-1β-induced GHS-R1a upregulation. IL-1β and F. nucleatum also enhanced the expressions of cyclooxygenase 2, CC-chemokine ligand 2, IL-6, IL-8, and matrix metalloproteinase 1, but these stimulatory effects were counteracted by GHRL. By contrast, the stimulatory actions of IL-1β and F. nucleatum on the GHS-R1a expression were further enhanced by GHRL. Our study provides original evidence that IL-1β and F. nucleatum regulate the GHS-R/GHRL system in osteoblast-like cells. Furthermore, we demonstrate for the first time that the proinflammatory and proteolytic actions of IL-1β and F. nucleatum on osteoblast-like cells are inhibited by GHRL. Our study suggests that microbial and inflammatory insults upregulate GHS-R1a, which may represent a protective negative feedback mechanism in human bone.

Proinflammatory cytokine levels and peri-implant parameters among cigarette smokers, individuals vaping electronic cigarettes, and non-smokers

BACKGROUND

Tobacco smoking compromises the prognosis of dental implant treatment and is associated with increased risk of peri-implant bone loss and increased implant failure rate. There is a dearth of studies that have compared clinical, radiographic, and immunological peri-implant parameters among cigarette smokers (CS), individuals vaping e-cigarettes (e-cigs), and non-smokers (NS). This study aimed to compare clinical and radiographic peri-implant parameters and levels of matrix metalloproteinase (MMP)-9 and interleukin (IL)-1β levels among CS, individuals' vaping e-cigs, and NS.

METHODS

Thirty-two CS (group 1), 31 individuals vaping e-cigs (group 2), and 32 NS (group 3) were included. Demographic- and implant-related data were collected using a structured baseline questionnaire. Peri-implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded and marginal bone loss (MBL) were assessed using standardized digital radiographs. Enzyme-linked immunosorbent assay was used to assess levels of MMP-9 and IL-1β in peri-implant sulcular fluid. Pearson correlation coefficient was used to analyze for correlations of MMP-9 and IL-1β levels with peri-implant parameters.

RESULTS

BOP showed significantly higher values in group 3 as compared with groups 1 and 2 (P < 0.01). PI (P < 0.01), PD ≥ 4 mm (P < 0.01), and mean concentrations of MMP-9 (P < 0.001) and IL-1β (P < 0.01) were significantly higher in groups 1 and 2 than group 3. MBL was significantly higher in group 1 as compared with group 2 and group 3 (P < 0.01). Significant positive correlations were found between MMP-9 (P = 0.0198) and IL-1β (P = 0.0047) levels and MBL in group 1; and a significant positive correlation between IL-1β and MBL in group 2 (P = 0.0031).

CONCLUSIONS

Peri-implant health was compromised among CS than vaping individuals and NS. Increased levels of proinflammatory cytokines in CS and vaping individuals may suggest greater peri-implant inflammatory response.

Peri-implant parameters, tumor necrosis factor-alpha, and interleukin-1 beta levels in vaping individuals

BACKGROUND

To the author's knowledge, there has been no study that has assessed clinical, radiographic, and immunological peri-implant parameters among individuals vaping e-cigarette (e-cig).

PURPOSE

This pilot study aimed to compare clinical and radiographic peri-implant parameters and levels of tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β levels among individuals vaping e-cigs and never smoker (NS).

MATERIALS AND METHODS

Forty-seven individuals vaping e-cigs (group-1) and 45 NS (group-2) were included. Demographic and implant-related data were collected using a structured baseline questionnaire. Peri-implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were recorded and peri-implant bone loss (PIBL) were assessed using standardized digital radiographs. Enzyme-linked immunosorbent assay was used to assess the levels of TNF-α and IL-1β in peri-implant sulcular fluid.

RESULTS

Bleeding on probing showed statistically significantly higher values in group-2 patients as compared to group-1 patients (P < .01). Probing depth ≥ 4 mm and PIBL was statistically significantly higher in group-1 patients as compared to group-2 patients (P < .05). Mean concentrations of TNF-α (P < .001) and IL-1β (P < .01) were statistically significantly increased in individuals in group 1 as compared with group 2. A significant positive correlations were found between TNF-α levels and BOP (P = .024) and PIBL (P = .016); and significant positive correlation was found between IL-1β and PIBL (P = .018) in group 1, respectively.

CONCLUSIONS

Clinical and radiographic peri-implant parameters are compromised among vaping individuals. Increased levels of proinflammatory cytokines in peri-implant sulcular fluid may suggest greater local inflammatory response in vaping individuals for peri-implant inflammation.

Effect of interleukin-1β on ghrelin receptor in periodontal cells

OBJECTIVES

Periodontopathogens induce immunoinflammatory responses characterized by the release of inflammatory mediators, e.g., interleukin (IL)-1β, IL-6, and IL-8. Ghrelin (GHRL) is an appetite hormone which mediates its effect via the functional receptor GHS-R1a. This study was to examine the effect of an inflammatory insult on GHS-R1a in human periodontal cells.

MATERIALS AND METHODS

Periodontal ligament (PDL) cells and gingival fibroblasts (HGFs) were exposed to IL-1β in the presence and absence of GHRL. Cells were also pre-incubated with specific inhibitors of NF-κB or MEK1/MEK2 signaling. Gene expression of GHS-R1a and proinflammatory mediators was assessed by real-time PCR, GHS-R1 protein level by immunocytochemistry, and NF-κB nuclear translocation by immunofluorescence.

RESULTS

IL-1β increased significantly the GHS-R1a expression in both cell types in a dose-dependent manner. The stimulatory effect of IL-1β involved the NF-κB and MAPK pathways. Exposure of cells to IL-1β also resulted in an increased production of GHS-R1 protein in both cell types. Furthermore, GHRL counteracted significantly the stimulatory actions of IL-1β on IL-6 and IL-8 in PDL cells.

CONCLUSIONS

This study demonstrates for the first time that IL-1β upregulates the functional ghrelin receptor in periodontal fibroblastic cells. Moreover, these results further support the assumption that the GHRL/GHS-R system exerts anti-inflammatory effects. Therefore, the upregulation of ghrelin receptor in periodontal cells in response to an inflammatory stimulus may represent a negative feedback mechanism to attenuate the initial inflammatory process in periodontal diseases.

CLINICAL RELEVANCE

The anti-inflammatory GHRL/GHS-R system may serve as a promising target for the prevention and therapy of periodontal diseases.

Damage-regulated autophagy modulator 1 in oral inflammation and infection

OBJECTIVES

Damage-regulated autophagy modulator (DRAM) 1 is a p53 target gene with possible involvement in oral inflammation and infection. This study sought to examine the presence and regulation of DRAM1 in periodontal diseases.

MATERIAL AND METHODS

In vitro, human periodontal ligament fibroblasts were exposed to interleukin (IL)-1β and Fusobacterium nucleatum for up to 2 days. The DRAM1 synthesis and its regulation were analyzed by real-time PCR, immunocytochemistry, and ELISA. Expressions of other autophagy-associated genes were also studied by real-time PCR. In vivo, synthesis of DRAM1 in gingival biopsies from rats and patients with and without periodontal disease was examined by real-time PCR and immunohistochemistry. For statistics, ANOVA and post-hoc tests were applied (p < 0.05).

RESULTS

In vitro, DRAM1 was significantly upregulated by IL-1β and F. nucleatum over 2 days and a wide range of concentrations. Additionally, increased DRAM1 protein levels in response to both stimulants were observed. Autophagy-associated genes ATG3, BAK1, HDAC6, and IRGM were also upregulated under inflammatory or infectious conditions. In vivo, the DRAM1 gene expression was significantly enhanced in rat gingival biopsies with induced periodontitis as compared to control. Significantly increased DRAM1 levels were also detected in human gingival biopsies from sites of periodontitis as compared to healthy sites.

CONCLUSION

Our data provide novel evidence that DRAM1 is increased under inflammatory and infectious conditions in periodontal cells and tissues, suggesting a pivotal role of DRAM1 in oral inflammation and infection.

CLINICAL RELEVANCE

DRAM1 might be a promising target in future diagnostic and treatment strategies for periodontitis.

Regulation of IL-1 signaling through control of focal adhesion assembly

IL-1 signaling is adhesion-restricted in many cell types, but the mechanism that drives it is not defined. We screened for proteins recruited to nascent adhesions in IL-1-treated human fibroblasts with tandem mass tag-mass spectrometry. We used fibronectin bead preparations to enrich 10 actin-associated proteins. There was a 1.2 times log 2-fold enrichment of actin capping protein (ACP) at 30 min after IL-1 stimulation. Knockdown (KD) of ACP by siRNA reduced IL-1-induced ERK activation(by 56%, matrix metalloproteinase-3 (MMP-3) expression by 48%, and MMP-9 expression by 62% (in all reductions, P < 0.01). Confocal or structured illumination microscopy showed that ACP was diffused throughout the cytosol but strongly accumulated at the ruffled border of spreading cells. ACP colocalized with nascent paxillin- and vinculin-containing adhesions at the ruffled border, but not with mature adhesions in the center. ACP KD promoted the formation of large, stable adhesions. Immunoprecipitation and proximity ligation analysis showed that ACP was associated with the IL-1 signal transduction proteins myeloid differentiation factor 88 (MyD88) and IL-1 receptor-associated kinase (IRAK) at the ruffled border of the leading edge. IL-1-induced phospho-ERK and MyD88 or IRAK colocalized at the leading edge. We concluded that ACP is required for recruitment and function of IL-1 signaling complexes in nascent adhesions at the leading edge of the cell.-Wang, Q., Delcorde, J., Tang, T., Downey, G. P., McCulloch, C. A. Regulation of IL-1 signaling through control of focal adhesion assembly.

Cytokine-based Predictive Models to Estimate the Probability of Chronic Periodontitis: Development of Diagnostic Nomograms

Although a distinct cytokine profile has been described in the gingival crevicular fluid (GCF) of patients with chronic periodontitis, there is no evidence of GCF cytokine-based predictive models being used to diagnose the disease. Our objectives were: to obtain GCF cytokine-based predictive models; and develop nomograms derived from them. A sample of 150 participants was recruited: 75 periodontally healthy controls and 75 subjects affected by chronic periodontitis. Sixteen mediators were measured in GCF using the Luminex 100™ instrument: GMCSF, IFNgamma, IL1alpha, IL1beta, IL2, IL3, IL4, IL5, IL6, IL10, IL12p40, IL12p70, IL13, IL17A, IL17F and TNFalpha. Cytokine-based models were obtained using multivariate binary logistic regression. Models were selected for their ability to predict chronic periodontitis, considering the different role of the cytokines involved in the inflammatory process. The outstanding predictive accuracy of the resulting smoking-adjusted models showed that IL1alpha, IL1beta and IL17A in GCF are very good biomarkers for distinguishing patients with chronic periodontitis from periodontally healthy individuals. The predictive ability of these pro-inflammatory cytokines was increased by incorporating IFN gamma and IL10. The nomograms revealed the amount of periodontitis-associated imbalances between these cytokines with pro-inflammatory and anti-inflammatory effects in terms of a particular probability of having chronic periodontitis.

Inflammatory cytokines in normal and irreversibly inflamed pulps: A systematic review

OBJECTIVE

To review the available literature in regard to the inflammatory process and pulpitis. Setting forth to evaluate if differences in the levels of various cytokines (TNF-α, IL-1β, IL-2, IL-6 and IL-8) can be observed in clinically diagnosed normal and irreversibly inflamed pulps that could serve as possible markers and/or diagnostic tools to predict and differentiate between certain states of inflammation. Methods used to measure and assess levels of cytokines have been limited to two protein quantification methods ELISA and/or Multiplex Array.

DESIGN

The databases PubMed, EMBASE/Ovid, The Cochrane Central Register of Controlled Trials, Cochrane Reviews and Scopus were consulted for the electronic literature search. Screening of titles and abstracts followed the PRISMA guidelines while data extraction and the assessment of the full texts were carried out in accordance to the GRADES assessment.

RESULTS

The review showed that significant increases in levels of IL-1β, IL-2, IL-6, IL-8 and TNF-α in irreversible pulpitis samples exist, in comparison to normal pulp samples which serve as a good basis for potential markers. Due to larger discrepancies in available literature, IL-2 seems rather unsuitable at the moment, while IL-6 and TNF alpha seem to be more promising.

CONCLUSION

It may be concluded that even by combining two protein quantification methods inconsistencies between studies exist. At the moment it is difficult to select just one specific cytokine suitable for testing, rather it supports the rationale that further high-quality clinical studies are needed.

Association of macrophage migration inhibitory factor gene polymorphisms with chronic periodontitis in a South Eastern Iranian population

Background:

Macrophage migration inhibitory factor (MIF) is a key proinflammatory mediator. It plays a vital role in immune response against the oral disease. MIF is a regulator of innate immunity, and bacterial antigens can stimulate serum level of this protein. In experimental gingivitis, the expression level of MIF increases and this increment positively correlates with oral plaque index. The single nucleotide polymorphisms in the gene encoding the MIF protein can control the function of MIF. The aim of the present study was a clarification of the associations between MIF-173 G/C, MIF 95 bp, and 189 bp insertion/deletion (I/D) polymorphisms and chronic periodontitis (CP) compared with healthy controls.

Materials and Methods:

This case–control study was carried out on 210 CP patients and 100 normal subjects. MIF-173 G/C and MIF 95 bp and 189 bp I/D polymorphisms were genotyped, using polymerase chain reaction–restriction fragment-length polymorphism (PCR-RFLP) and PCR, respectively. Allele and genotype frequencies of the variants were compared between patients and controls using Chi-square. test. The value of P < 0.05 was considered statistically significant.

Results:

The study findings showed that MIF-173 G/C polymorphism, especially the C allele increased the risk of CP. The 95-bp I/D polymorphism was not associated with CP and the 185-bp I/D variant was not polymorphic in our population.

Conclusion:

Therefore, MIF-137 G/C variant increased the risk of CP in the South East of the Iranian population. In other words, polymorphisms in MIF gene influence clinical outcome of CP infection and influence the susceptibility to disease. Further studies with larger sample sizes and different ethnicities are required to validate our findings.

Estimation of interleukin-18 in the gingival crevicular fluid and serum of Bengali population with periodontal health and disease

Context:

Host's immune response elicits cytokines in response to bacterial challenge. We explore role of one such cytokine interleukin-18 (IL-18) in periodontal health and disease.

Aims:

IL-18 is a pro-inflammatory and tumor suppressive cytokine. Dental literatures suggest that IL-18 might have a role to play in the progression from oral health to periodontal disease. Therefore, this study was undertaken to elucidate the level and role of IL-18 in the gingival crevicular fluid (GCF) and serum of individuals with healthy gingiva, chronic gingivitis, chronic periodontitis, and aggressive periodontitis before and after periodontal therapy.

Settings and Design:

Eighty individuals chosen for the study were divided into healthy control group (1A), chronic gingivitis (2A), chronic periodontitis (3A), and aggressive periodontitis (4A) with twenty individuals each. Criteria for the division were the subject's gingival index, probing pocket depth, clinical attachment loss, and radiographic evidence of bone loss.

Materials and Methods:

The individuals underwent treatment (scaling in case of Groups 1A and 2A and scaling and root planing followed by flap surgery in Groups 3A and 4A) to form posttreatment Groups 1B, 2B, 3B, and 4B, respectively. Thus, a total of 160 GCF and 160 serum samples were collected and tested by ELISA.

Statistical Analysis Used:

Intergroup comparison was done by post hoc Tukey's test.

Results:

The mean IL-18 concentration was greatest in Group 3A (GCF 144.61 pg/μl, serum 55.12 pg/ml) followed by Group 4A (GCF 98.55 pg/μl, serum 39.06 pg/ml), Group 2A (GCF 22.27 pg/μl, serum 27.73 pg/ml) and lowest (GCF 17.94 pg/μl, serum 11.49 pg/ml) in Group 1A. Posttreatment groups (1B–4B) showed reduction in the mean IL-18 concentration in both GCF and serum.

Conclusions:

As the inflammation increased, there was a concomitant increase in the level of IL-18 and vice versa following periodontal therapy.

Relationship between interleukin 1α levels in the gingival crevicular fluid in health and in inflammatory periodontal disease and periodontal inflamed surface area: A correlative study

Background:

Periodontitis has been suggested as a source of inflammation for pathological changes in distant sites. Interleukin-1 alpha (IL-1α) has shown to have specific roles in inflammation, immunity, tissue breakdown, and tissue homeostasis. This study assessed the correlation of periodontal inflamed surface area (PISA) index with the gingival crevicular fluid (GCF) levels of IL-1α, which would be helpful in evaluating the validity of PISA index in terms of reflection of the disease.

Materials and Methods:

A total of 40 subjects were recruited for this study and 20 subjects with healthy gingiva (Group I) served as controls and 20 subjects served as cases with periodontitis (Group II). Samples of GCF were obtained from one site in each patient by placing color-coded, calibrated, volumetric microcapillary pipettes extracrevicularly, and subjected to ELISA test.

Results:

There was a statistical significance for mean probing depth (PD) and periodontal epithelial surface area (PESA) (P < 0.01), mean bleeding on probing and PISA, IL-1α (P < 0.01) and PESA (P < 0.05) in Group I. Statistical significance was found between PISA and IL-1α in Group I (P < 0.01). A positive correlation was found in Group II between mean PD and mean attachment loss (P < 0.01), PISA, IL-1α and PESA (P < 0.01), PISA and IL-1α levels (P < 0.01) which was statistically significant.

Conclusion:

The inflammatory burden index was statistically significant in the periodontitis group correlating with higher IL-1α levels, which clearly indicates the validity of PISA index.

Leptin effects on the regenerative capacity of human periodontal cells

Obesity is increasing throughout the globe and characterized by excess adipose tissue, which represents a complex endocrine organ. Adipose tissue secrets bioactive molecules called adipokines, which act at endocrine, paracrine, and autocrine levels. Obesity has recently been shown to be associated with periodontitis, a disease characterized by the irreversible destruction of the tooth-supporting tissues, that is, periodontium, and also with compromised periodontal healing. Although the underlying mechanisms for these associations are not clear yet, increased levels of proinflammatory adipokines, such as leptin, as found in obese individuals, might be a critical pathomechanistic link. The objective of this study was to examine the impact of leptin on the regenerative capacity of human periodontal ligament (PDL) cells and also to study the local leptin production by these cells. Leptin caused a significant downregulation of growth (TGFβ1, and VEGFA) and transcription (RUNX2) factors as well as matrix molecules (collagen, and periostin) and inhibited SMAD signaling under regenerative conditions. Moreover, the local expression of leptin and its full-length receptor was significantly downregulated by inflammatory, microbial, and biomechanical signals. This study demonstrates that the hormone leptin negatively interferes with the regenerative capacity of PDL cells, suggesting leptin as a pathomechanistic link between obesity and compromised periodontal healing.

Beneficial effects of adiponectin on periodontal ligament cells under normal and regenerative conditions

Type 2 diabetes and obesity are increasing worldwide and linked to periodontitis, a chronic disease which is characterized by the irreversible destruction of the tooth-supporting tissues, that is, periodontium. The mechanisms underlying the association of diabetes mellitus and obesity with periodontal destruction and compromised periodontal healing are not well understood, but decreased plasma levels of adiponectin, as found in diabetic and obese individuals, might be a critical mechanistic link. The aim of this in vitro study was to examine the effects of adiponectin on periodontal ligament (PDL) cells under normal and regenerative conditions, and to study the regulation of adiponectin and its receptors in these cells. Adiponectin stimulated significantly the expression of growth factors and extracellular matrix, proliferation, and in vitro wound healing, reduced significantly the constitutive tumor necrosis factor-α expression, and caused a significant upregulation of its own expression. The beneficial actions of enamel matrix derivative on a number of PDL cell functions critical for periodontal regeneration were partially enhanced by adiponectin. The periodontopathogen Porphyromonas gingivalis inhibited the adiponectin expression and stimulated the expression of its receptors. In conclusion, reduced levels of adiponectin, as found in type 2 diabetes and obesity, may compromise periodontal health and healing.

Regulation of NAMPT in human gingival fibroblasts and biopsies

Adipokines, such as nicotinamide phosphoribosyltransferase (NAMPT), are molecules, which are produced in adipose tissue. Recent studies suggest that NAMPT might also be produced in the tooth-supporting tissues, that is, periodontium, which also includes the gingiva. The aim of this study was to examine if and under what conditions NAMPT is produced in gingival fibroblasts and biopsies from healthy and inflamed gingiva. Gingival fibroblasts produced constitutively NAMPT, and this synthesis was significantly increased by interleukin-1β and the oral bacteria P. gingivalis and F. nucleatum. Inhibition of the MEK1/2 and NFκB pathways abrogated the stimulatory effects of F. nucleatum on NAMPT. Furthermore, the expression and protein levels of NAMPT were significantly enhanced in gingival biopsies from patients with periodontitis, a chronic inflammatory infectious disease of the periodontium, as compared to gingiva from periodontally healthy individuals. In summary, the present study provides original evidence that gingival fibroblasts produce NAMPT and that this synthesis is increased under inflammatory and infectious conditions. Local synthesis of NAMPT in the inflamed gingiva may contribute to the enhanced gingival and serum levels of NAMPT, as observed in periodontitis patients. Moreover, local production of NAMPT by gingival fibroblasts may represent a possible mechanism whereby periodontitis may impact on systemic diseases.

Clinical and subclinical effects of power brushing following experimental induction of biofilm overgrowth in subjects representing a spectrum of periodontal disease

AIM

Investigate short-term effects of power brushing following experimental induction of biofilm overgrowth in periodontal disease states.

MATERIALS AND METHODS

Overall, 175 subjects representing each of five biofilm-gingival interface (BGI) periodontal groups were enrolled in a single-blind, randomized study. After stent-induced biofilm overgrowth for 21 days subjects received either a manual or a power toothbrush to use during a 4 weeks resolution phase. At baseline and during induction and resolution, standard clinical parameters were measured. Subclinical parameters included multikine analysis of 13 salivary biomarkers and 16s Human Oral Microbe Identification Microarray (HOMIM) probe analysis of subgingival plaque samples.

RESULTS

All groups exhibited significantly greater reductions in bleeding on probing (BOP) (p = 0.002), gingival index (GI) (p = 0.0007), pocket depth (PD) (p = 0.04) and plaque index (p = 0.001) with power brushing compared to manual. When BGI groups were combined to form a shallow PD (PD ≤ 3 mm) and a deep PD group (PD > 4 mm) power brushing reduced BOP and GI in subjects with both pocket depths. Power brushing significantly reduced IL-1β levels at resolution while changes in bacterial levels showed non-significant trends between both brushing modalities.

CONCLUSIONS

Short-term changes in select clinical parameters and subclinical salivary biomarkers may be useful in assessing efficacy of power brushing interventions in a spectrum of periodontal disease states.

IL-4 inhibition of IL-1 induced Matrix metalloproteinase-3 (MMP-3) expression in human fibroblasts involves decreased AP-1 activation via negative crosstalk involving of Jun N-terminal kinase (JNK)

Matrix metalloproteinase-3 (MMP-3) over-expression is associated with tissue destruction in the context of chronic inflammation. Previous studies showed that IL-4 inhibits induction of MMP-3 by IL-1β, and suggested that AP-1 might be involved. Here we show that IL-1 induced binding of transcription factor AP-1 to the MMP-3 promoter consists primarily of c-Jun, JunB, and c-Fos and that binding of c-Jun and c-Fos is inhibited by the combination of cytokines while binding of Jun B is not. Mutation of the AP-1 site in the MMP-3 promoter decreased the ability of IL-4 to inhibit its transcription in transfected MG-63 cells. Western blotting showed that both cytokines activate Jun N-terminal kinase (JNK), but with somewhat different kinetics, and that activation of JNK by both cytokines individually is inhibited by the combination. These results indicate that IL-4 inhibition of MMP-3 expression is associated with reduction of IL-1 induced binding of active forms of the AP-1 dimer, while less active JunB-containing dimers remain, and suggest that these changes are associated with decreased activation of JNK.

Effects of Polycan, a β-glucan, on experimental periodontitis and alveolar bone loss in Sprague-Dawley rats

BACKGROUND AND OBJECTIVE

Polycan is a promising candidate for the treatment of periodontal disease. This study was undertaken to examine whether Polycan, a type of β-glucan, has a protective effect on ligature-induced experimental periodontitis and related alveolar bone loss in Sprague-Dawley rats.

MATERIAL AND METHODS

 Polycan was orally administered, daily, for 10 d, at 21.25, 42.5 or 85 mg/kg, beginning 1 d after ligation. Changes in body weight and alveolar bone loss were monitored, and the anti-inflammatory effects of Polycan were determined by measuring the levels of myeloperoxidase (MPO), interleukin-1beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) in gingival tissue. We also evaluated inducible nitric oxide synthase (iNOS) activity and malondialdehyde (MDA) concentrations as a measure of the antioxidant effect.

RESULTS

Ligature placement led to a marked decrease in body weight, increased alveolar bone loss and increased concentrations of MPO, IL-1β, TNF-α and MDA, as well as increased iNOS activity and inflammatory cell infiltration and decreased collagen-fiber content. Histological examination revealed increases in the number and activity of osteoclast cells, decreases in alveolar bone volume and elevated percentages of osteclasts on the alveolar bone surface. Daily oral treatment with 42.5 or 85 mg/kg of Polycan for 10 d led to significant, dose-dependent inhibition of the effect of ligature placement.

CONCLUSION

Taken together, these results suggest that 10 d of oral treatment with Polycan effectively inhibits ligature placement-induced periodontitis and related alveolar bone loss via an antioxidant effect.

Interactions of adiponectin and lipopolysaccharide from Porphyromonas gingivalis on human oral epithelial cells

BACKGROUND

Periodontitis is an inflammatory disease caused by pathogenic microorganisms, such as Porphyromonas gingivalis, and characterized by the destruction of the periodontium. Obese individuals have an increased risk for periodontitis and show decreased serum levels of adiponectin. This in-vitro study was established to examine whether adiponectin modulates critical effects of lipopolysaccharide (LPS) from P. gingivalis on oral epithelial cells (OECs).

METHODOLOGY/PRINCIPAL FINDINGS

The presence of adiponectin and its receptors in human gingival tissue samples and OECs was analyzed by immunohistochemistry and PCR. Furthermore, OECs were treated with LPS and/or adiponectin for up to 72 h, and the gene expression and protein synthesis of pro- and anti-inflammatory mediators, matrix metalloproteinases (MMPs) and growth factors were analyzed by real-time PCR and ELISA. Additionally, cell proliferation, differentiation and in-vitro wound healing were studied. The nuclear translocation of NFκB was investigated by immunofluorescence. Gingival tissue sections showed a strong synthesis of adiponectin and its receptors in the epithelial layer. In cell cultures, LPS induced a significant up-regulation of interleukin (IL) 1β, IL6, IL8, MMP1 and MMP3. Adiponectin abrogated significantly the stimulatory effects of LPS on these molecules. Similarly, adiponectin inhibited significantly the LPS-induced decrease in cell viability and increase in cell proliferation and differentiation. Adiponectin led to a time-dependent induction of the anti-inflammatory mediators IL10 and heme oxygenase 1, and blocked the LPS-stimulated NFκB nuclear translocation.

CONCLUSIONS/SIGNIFICANCE

Adiponectin may counteract critical actions of P. gingivalis on oral epithelial cells. Low levels of adiponectin, as observed in obese individuals, may increase the risk for periodontal inflammation and destruction.

Increased expression of C-reactive protein gene in inflamed gingival tissues could be derived from endothelial cells stimulated with interleukin-6

BACKGROUND

Epidemiological studies have suggested periodontitis as a risk factor for ischemic heart disease. High sensitive C-reactive protein (hs-CRP), a predictor of cardiovascular risk, is elevated in periodontitis patients. Therefore, local infection-induced elevation of systemic CRP could account for the relationship between the 2 diseases. However, the underlying mechanism of CRP production in the periodontal tissues has not been fully elucidated. Therefore, the aim of the present study was to clarify the mechanism of CRP production in periodontal tissues.

METHODS

Gene expression of CRP in gingival biopsies was analysed by quantitative PCR. Human gingival epithelial cells (HGECs), human gingival fibroblasts (HGFBs), and human coronary artery endothelial cells (HCAECs) were characterized for CRP-producing ability by incubating with interleukin (IL)-1β, IL-6, soluble IL-6 receptor (sIL-6R), and Porphyromonas gingivalis strain W83.

RESULTS

Gene expression of CRP is significantly elevated in periodontitis lesions compared with gingivitis lesions. HCAECs, but not HGECs and HGFBs, produced CRP in response to IL-6 and IL-1β in the presence of sIL-6R. In contrast to IL-6, the effect of IL-1β on CRP production was indirect via induction of IL-6. IL-1β was produced by HGECs and HGFBs with stimulation of P. gingivalis antigens.

CONCLUSION

These results suggest that CRP induced locally by periodontal infection may play another role in the pathogenesis of periodontal disease, and to a much lesser extent, has the potential to modulate systemic CRP level by extra-hepatic CRP production.

Salivary interleukin-1β levels in patients with chronic periodontitis before and after periodontal phase I therapy and healthy controls: a case-control study

BACKGROUND

The role of interleukin (IL)-1β in periodontal disease pathogenesis is well researched. This study aimed to assess and compare the salivary IL-1β levels in patients with chronic periodontitis before and after periodontal phase I therapy and periodontally healthy controls. Further, relationships between IL-1β levels and various clinical parameters were explored.

METHODS

Twenty-eight patients with moderate-to-severe generalized chronic periodontitis and 24 age-, race-, and ethnicity-matched controls participated in this study. Saliva samples were obtained from all patients. The clinical parameters recorded were clinical attachment loss (AL), probing depth, bleeding on probing, periodontal index, and gingival index. Clinical evaluation and sample collection were repeated 1 month after periodontal phase I therapy in patients with periodontitis. IL-1β levels were assessed using enzyme-linked immunosorbent assay.

RESULTS

Mean IL-1β levels in patients with periodontitis at baseline (1,312.75 pg/mL) were significantly higher (P <0.0001; eight-fold) than in controls (161.51 pg/mL). Although treatment in patients with periodontitis resulted in significant reduction in IL-1β levels (mean: 674.34 pg/mL; P = 0.001), they remained significantly higher (P <0.0001; four-fold) than control levels. There were significant correlations between IL-1β levels and all clinical parameters (P <0.01) except percentage sites with clinical AL >2 mm (P >0.05).

CONCLUSIONS

The data indicate that IL-1β levels are raised in the saliva of patients with chronic periodontitis, which are reduced after phase I therapy, suggesting a close association between salivary IL-1β and periodontitis. Additional longitudinal studies are needed to validate salivary IL-1β as a marker for periodontal disease.

Anti-inflammatory effects of EMD in the presence of biomechanical loading and interleukin-1β in vitro

Enamel matrix derivative (EMD) used to promote periodontal regeneration has been shown to exert anti-inflammatory effects. This in vitro study was performed to investigate if the anti-inflammatory actions of EMD are modulated by the local cellular environment, such as inflammation or occlusal, i.e., biomechanical, loading. Human periodontal ligament cells were seeded on BioFlex plates and incubated with EMD under normal, inflammatory, and biomechanical loading conditions for 1 and 6 days. In order to mimic inflammatory and biomechanical loading conditions in vitro, cells were stimulated with interleukin (IL)-1β and exposed to dynamic tensile strain, respectively. The gene expression of IL-1β, IL-1 receptor antagonist (IL-1RN), IL-6, IL-8, IL-10, and cyclooxygenase (COX)-2 was analyzed by real-time RT-PCR and the IL-6 protein synthesis by enzyme-linked immunoassay. For statistical analysis, Student's t test, ANOVA, and post-hoc comparison tests were applied (p < 0.05). EMD downregulated significantly the expression of IL-1β and COX-2 at 1 day and of IL-6, IL-8, and COX-2 at 6 days in normal condition. In an inflammatory environment, the anti-inflammatory actions of EMD were significantly enhanced at 6 days. In the presence of low biomechanical loading, EMD caused a downregulation of IL-1β and IL-8, whereas high biomechanical loading significantly abrogated the anti-inflammatory effects of EMD at both days. Neither IL-1RN nor IL-10 was upregulated by EMD. These data suggest that high occlusal forces may abrogate anti-inflammatory effects of EMD and should, therefore, be avoided immediately after the application of EMD to achieve best healing results.

Correlation of levels of interleukin-1β in gingival crevicular fluid to the clinical parameters of chronic periodontitis

AIM

BACKGROUND AND OBJECTIVES

IL-1β is a potent stimulator of bone resorption and has been implicated in the pathogenesis of periodontal destruction. Therefore, this study was designed to compare the levels of IL-1β of chronic periodontitis patients with the healthy subjects. Another objective of this study was to correlate IL-1β levels with the clinical parameters of the periodontal disease progression.

METHODS

For this study, total 60 subjects were chosen (30- healthy and 30-chronic periodontitis). Simplified oral hygiene index (OHI-S), gingival index (GI), periodontal disease index (PDI), probing depth (PD), tooth mobility, bleeding on probing (BOP) were recorded for all the subject. Gingival crevicular fluid (GCF) was collected and subjected for ELISA for estimation of IL-1β.

RESULTS

At the periodontal diseased sites, the IL-1β levels increased at least 2-fold as compared with healthy subjects. This increase was highly significant (p = 0.0000). Within the test group, IL-1β levels correlated positively and significantly with PDI, PD, BOP and tooth mobility. The correlations of IL-1β with PD (p = 0.000) and IL-1β with BOP (p = 0.0004) were highly significant.

INTERPRETATION AND CONCLUSION

These data suggest that amount of GCF IL-1β is closely associated with periodontal status. This relationship may be valuable in monitoring periodontal disease activity.

CLINICAL SIGNIFICANCE

It could be stated from this study on IL- 1β that there seem to be a strong correlation between periodontal tissue destruction and IL-1β. Furthermore IL-1β level could also differentiate between active and inactive periodontal lesions.

Nitric oxide synthase in gingival tissues of patients with chronic periodontitis and with and without diabetes

BACKGROUND

The purpose of this study was to evaluate the expression of inducible nitric oxide synthase (iNOS) in the gingival tissues of periodontitis patients with and without type 2 diabetes to assess whether NO plays a role in the severity of periodontitis in patients with diabetes. Patients with diabetes and healthy patients were used as controls.

METHODS

A total of 80 patients were evaluated in four groups (with 20 subjects each): patients with chronic periodontitis and diabetes (12 males and eight females; mean age, 52.1 +/- 6.9 years), patients with chronic periodontitis who were otherwise healthy (12 males and eight females; mean age, 43.1 +/- 8.9 years), periodontally healthy patients with diabetes (12 males and eight females; mean age 50.9 +/- 6.3 years), and systemically and periodontally healthy control subjects (12 males and eight females; mean age 29.8 +/- 9.2 years). Periodontal parameters were recorded. Immunohistochemistry was used to detect inflammation and iNOS expression in gingival tissues.

RESULTS

Although periodontal parameters were slightly higher in periodontitis compared to diabetic periodontitis, immunohistochemical parameters were higher in diabetic periodontitis compared to periodontitis. All periodontal parameters were higher in patients with periodontitis and with/without diabetes compared to controls and patients with diabetes. All immunohistochemical parameters were higher in patients with diabetes and periodontitis compared to patients with only diabetes or periodontitis, but there was no difference between the latter two groups. There was a correlation between the expression of iNOS and inflammatory cells in controls, patients with diabetes, and patients with periodontitis but not in patients with diabetes and periodontitis.

CONCLUSIONS

Inflammation and iNOS expression were more prominent in the gingiva of the patients with both diabetes and periodontitis. However, iNOS expression did not seem to have an additional detrimental effect on the course of periodontitis in patients with diabetes compared to those with periodontitis alone.

Irsogladine maleate counters the interleukin-1 beta-induced suppression in gap-junctional intercellular communication but does not affect the interleukin-1 beta-induced zonula occludens protein-1 levels in human gingival epithelial cells

BACKGROUND AND OBJECTIVE

Irsogladine maleate counters gap junctional intercellular communication reduction induced by interleukin-8 or Actinobacillus actinomycetemcomitans in cultured human gingival epithelial cells. Interleukin-1 beta is involved in periodontal disease. Little is known, however, about the effect of interleukin-1 beta on intercellular junctional complexes in human gingival epithelial cells. Furthermore, irsogladine maleate may affect the actions of interleukin-1 beta. In this study, we examined how interleukin-1 beta affected gap junctional intercellular communication, connexin 43 and zonula occludens protein-1, and how irsogladine maleate modulated the interleukin-1 beta-induced changes in the intercellular junctional complexes in human gingival epithelial cells.

MATERIAL AND METHODS

Human gingival epithelial cells were exposed to interleukin-1 beta, with or without irsogladine maleate. Connexin 43 and zonula occludens protein-1 were examined at mRNA and protein levels by real-time polymerase chain reaction and western blotting, respectively. Gap junctional intercellular communication was determined using the dye transfer method. The expression of zonula occludens protein-1 was also confirmed by immunofluorescence.

RESULTS

Interleukin-1 beta decreased connexin 43 mRNA levels, but increased zonula occludens protein-1 mRNA levels. Irsogladine maleate countered the interleukin-1 beta-induced reduction in gap junctional intercellular communication and connexin 43 levels. However, irsogladine maleate did not influence the increased zonula occludens protein-1 levels.

CONCLUSION

The effect of interleukin-1 beta on gap junctional intercellular communication and tight junctions of human gingival epithelial cells is different. The recovery of gap junctional intercellular communication by irsogladine maleate in the gingival epithelium may be a normal process in gingival epithelial homeostasis.

Either integrin subunit beta1 or beta3 is involved in mediating monocyte adhesion, IL-1beta protein and mRNA expression in response to surfaces functionalized with fibronectin-derived peptides

We synthesized gelatin-based, interpenetrating network (IPN) scaffolds immobilized with fibronectin (FN)-derived peptides to assess monocyte-biomaterial interaction. Human primary monocytes were seeded onto peptide-grafted IPN or tissue-culture polystyrene (TCPS) pre-adsorbed with FN or FN-derived peptides. Monocyte cell density on both TCPS and IPN surfaces was higher in the presence of the arginine-glycine-aspartic acid (RGD) peptide. Pretreatment with anti-integrin beta1 or beta3 antibody decreased monocyte density on all ligand-modified TCPS and IPN. Interleukin-1 beta (IL-1beta) protein levels of cells on modified TCPS decreased over time. IL-1beta expression of monocytes in the presence of IPNs peaked at 24 h and then decreased through 168 h. Ligand identity did not affect IL-1beta expression in either TCPS or IPN samples. Pretreatment with anti-integrin beta1 or beta3 antibody reduced IL-1beta levels from both TCPS and IPN samples in a ligand-independent manner, particularly at 24 h. Monocytic IL-1beta mRNA expression in IPN samples without antibody pretreatment was highest at 2 h and decreased over time. IL-1beta mRNA expression in cells with anti-integrin beta1 or beta3 antibody pretreatment was similar to those without antibody pretreatment, except for methoxygrafted IPN samples. The change in IL-1beta mRNA expression did not correlate with changes in protein expression. The results indicate that monocyte adhesion was affected by the substrate and the RGD sequence and beta1 or beta3 containing integrin receptors. beta1- or beta3-containing integrin receptors were also involved in IL-1beta gene and protein expression in monocytes adhered to gelatin-based biomaterial surfaces.

Gingival Concentrations of Interleukin-23 and -17 at Healthy Sites and at Sites of Clinical Attachment Loss

BACKGROUND

The presence of interleukin (IL)-23 has not been reported within inflamed gingiva, so we evaluated its concentration within gingiva from normal sites and sites of chronic periodontal disease.

METHODS

Gingiva was obtained prior to extraction of teeth. It was grouped based on clinical attachment loss (CAL): 0 to 2 mm (normal-slight), 3 to 4 mm (moderate), and >5 mm (severe). Tissues were solubilized, and IL-12, -23, -6, -17, and -1beta; interferon-gamma (IFN-gamma); and tumor necrosis factor-alpha (TNF-alpha) concentrations were assessed by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance, post hoc Tukey test, and Pearson correlation test. Groups were defined as significantly different when P <0.05.

RESULTS

The gingival concentrations of IL-23, -17, -1beta, and -6 and IFN-gamma were significantly greater at moderate CAL sites than at normal-slight CAL sites. Gingival concentrations of IL-23, -1beta, -17, and -6 and TNF-alpha were significantly greater at severe CAL sites than at normal-slight CAL sites. In addition, the gingival concentrations of IL-23, -17, and -6 and TNF-alpha were significantly greater and the gingival concentrations of IL-12 and IFN-gamma were significantly lower at severe CAL sites than at moderate CAL sites. Gingival concentrations of IL-23, -17, -6, and -1beta and TNF-alpha correlated positively with CAL. The IL-23 gingival concentration correlated significantly with IL-17, -1beta, and -6 and TNF-alpha concentrations and correlated negatively with IL-12 and IFN-gamma concentrations.

CONCLUSIONS

Our results suggested the possibility that the IL-23/IL-17 immune response was present within chronically inflamed gingiva. This is a host response that had not been reported previously in periodontal disease and may be an important factor in the chronic nature of the disease.

Levels of gingival tissue platelet activating factor after conventional and regenerative periodontal surgery

The hypothesis, a relationship between gingival tissue platelet activating factor (PAF) levels and healing after periodontal surgery, was tested by measuring PAF levels in gingival tissues collected from sites that had undergone flap surgery and guided tissue regeneration (GTR) or flap surgery alone. Using a split-mouth design, 20 intrabony defects were randomly assigned to treatment with flap surgery and GTR (group 1) or with flap surgery alone (group 2). Gingival tissue samples were obtained at surgery (baseline) and at 6-month follow-up evaluation visit. One half of each sample was used for analysis of PAF levels by high-performance liquid chromatography, and the other half of the sample was used for histomorphometric analysis that included measurements of number and diameter of blood vessels. PAF levels and diameter of blood vessels were significantly decreased (p < 0.01), and the number of blood vessels was significantly increased (p < 0.05) in both groups after 6 months compared to the baseline values. Postoperative number of blood vessels were significantly higher in group 1 (p < 0.05), whereas there was no significant difference in postoperative PAF levels between the two groups (p > 0.05). Based on the reported results, it is suggested that a decrease in gingival PAF levels might be found after conventional and regenerative periodontal surgery.

Interleukin-4 inhibition of interleukin-1-induced expression of matrix metalloproteinase-3 (MMP-3) is independent of lipoxygenase and PPARgamma activation in human gingival fibroblasts

Background

Interleukin 4 (IL-4) has been shown to suppress interleukin-1 (IL-1) induced expression of matrix metalloproteinase-3 (MMP-3) in human synovial and gingival fibroblasts, but the mechanism of suppression has not been determined. Activators of peroxisome proliferator-activated receptor-γ (PPARγ) have been shown to inhibit cytokine induced expression of MMPs in other cell types, and IL-4 has been shown to activate PPARγ by stimulating production of ligands through the lipoxygenase pathway. It has been suggested that PPARγ may inhibit expression of MMPs by competing with transcription factor AP-1 for binding to a putative composite binding element in the promoters. The objective of this study was to determine whether the suppressive effects of IL-4 on the IL-1 induced expression of MMP-3 involve activation of lipoxygenase and/or PPARγ.

Results

Western blotting revealed the presence of PPARγ in nuclear extract of HGF. IL-1 induced binding of nuclear extract to the putative composite PPRE/AP-1 site was diminished in the presence of pioglitazone, but there was no evidence of any change in the composition of the retarded complexes, and no evidence of PPARγ binding to this site. Nordihydroguaiaretic acid (NDGA), a non-selective lipoxygenase inhibitor, and MK886, a specific inhibitor of 5-lipoxygenase, induced MMP-3 expression synergistically with IL-1. However IL-4 was still able to inhibit MMP-3 expression in the presence of NDGA or MK886 and IL-1. Activation of PPARγ with pioglitazone not only failed to inhibit IL-1 induced expression of MMP-3 mRNA, but rather super-induced MMP-3 in the presence of IL-1. PPARγ antagonist GW9662 failed to abolish the suppressive effects of IL-4. Another PPARγ activator, 15-deoxy-Delta12,14prostaglandin J2 (15dPGJ2), also super-induced MMP-3 mRNA, and this was due at least in part to increased transcription.

Conclusion

IL-4 suppression of IL-1-induced MMP-3 expression in HGF is independent of lipoxygenase activity and activation of PPARγ. Super-induction of MMP-3 by pioglitazone may have important implications for patients using pioglitazone to treat type II diabetes in the presence of chronic inflammation.

Comparison of clinical, radiographic and immunological parameters of teeth and different dental implant platforms

A comparison between host response in teeth and dental implants was not made. Likewise, the association between host response and periodontal parameters has never been explored. The purpose of this study was to compare periodontal health around natural teeth and dental implants with different restorative platforms. Twenty-seven partially edentulous patients with dental implants, either external hex butt joint (n=28) or tapered Morse (n=45), were included in this study. Implants were in function for 1-6 years (mean 2.9). Plaque index (PI), gingival index (GI), probing depth (PD); and clinical attachment level (CAL), were recorded at final examination; alveolar bone loss (ABL) was measured at baseline and final examination using panoramic radiographs. Gingival crevicular fluid samples were obtained from the Ramfjord index teeth and all implants and assayed using enzyme-linked immunosorbent assay for prostaglandin E(2) (PGE(2)), interleukin-1 (IL-1) and tumour necrosis factor alpha (TNFalpha). Differences between teeth and implants and between the two implant platforms were compared using Student's t-test. Correlations between cytokines, ABL and clinical parameters were analyzed using Pearson's co-efficient test. PI and GI were significantly higher in teeth than dental implants (1.2+/-0.5 vs. 0.8+/-0.5, P=0.0018; 1.2+/-0.3 vs. 1.1+/-0.3, P=0.048). Conversely, PD was deeper in implants (2.66+/-0.6 vs. 3.66+/-0.9, P=0.001). GI and PD around teeth and implants were positively associated (R=0.561, P=0.0023; R=0.39, P=0.0452). Greater ABL was observed around dental implants (1.62+/-2.2 mm) compared with teeth (0.49+/-0.3 mm). A positive correlation was found between both IL-1 (R=0.73, P=0.0064; R=0.52, P=0.0081) and TNFalpha (R=0.64, P=0.0246; R=0.46, P=0.091) and ABL in teeth and implants. Both implant platforms were similar clinically and radiographically; however, TNFalpha (2.49+/-0.3 vs. 4.79+/-0.5, P=0.004) and IL-1 (24.52+/-7.3 vs. 45.41+/-9.9, P=0.095) were higher for the non-submerged implants. In conclusion, IL-1 and TNFalpha are sensitive markers of ABL around teeth and implants. The two dental implant platforms showed a similar clinical and radiographic response; however, the greater host response in the non-submerged implants might suggest future bone loss.

Phosphorylation of SHP-2 Regulates Interactions between the Endoplasmic Reticulum and Focal Adhesions to Restrict Interleukin-1-induced Ca2+ Signaling

Interleukin-1 (IL-1)-induced Ca2+ signaling in fibroblasts is constrained by focal adhesions. This process involves the proteintyrosine phosphatase SHP-2, which is critical for IL-1-induced phosphorylation of phospholipase Cgamma1, thereby enhancing IL-1-induced Ca2+ release and ERK activation. Currently, the mechanisms by which SHP-2 modulates Ca2+ release from the endoplasmic reticulum are not defined. We used immunoprecipitation and fluorescence protein-tagged SHP-2 or endoplasmic reticulum (ER)-protein expression vectors, and an ER-specific calcium indicator, to examine the functional relationships between SHP-2, focal adhesions, and IL-1-induced Ca2+ release from the ER. By total internal reflection fluorescence microscopy to image subplasma membrane compartments, SHP-2 co-localized with the ER-associated proteins calnexin and calreticulin at sites of focal adhesion formation in fibroblasts. IL-1beta promoted time-dependent recruitment of SHP-2 and ER proteins to focal adhesions; this process was blocked in cells treated with small interfering RNA for SHP-2 and in cells expressing a Y542F SHP-2 mutant. IL-1 stimulated inositol 1,4,5-trisphosphate receptor-mediated Ca2+ release from the ER subjacent to the plasma membrane that was tightly localized around fibronectin-coated beads and was reduced 4-fold in cells expressing Tyr-542 SHP-2 mutant. In subcellular fractions enriched for ER proteins, immunoprecipitation demonstrated that IL-1-enhanced association of SHP-2 with the type 1 inositol 1,4,5-trisphosphate receptor was dependent on Tyr-542 of SHP-2. We conclude that Tyr-542 of SHP-2 modulates IL-1-induced Ca2+ signals and association of the ER with focal adhesions.

Interleukin-1 beta, interleukin-12 and interleukin-18 levels in gingival fluid and serum of patients with gingivitis and periodontitis

INTRODUCTION

Cytokines are of major importance in periodontal disease progression. Interleukin-12 (IL-12) stimulates interferon-gamma production by T helper type 1 (Th1) cells while IL-18 induces Th1 responses when present with IL-12 but Th2 responses in the absence of IL-12. IL-1beta has been correlated with periodontal disease destruction. This study determined the local concentrations of these cytokines in sites of gingivitis and periodontitis.

METHODS

Gingival crevicular fluid was collected from two sites in each of 10 gingivitis patients and from two gingivitis sites and two periodontitis sites from each of 10 periodontitis patients. Serum samples were also collected. IL-1beta, biologically active IL-12 p70, the IL-12 p40 subunit and IL-18 concentrations were determined by enzyme-linked immunoabsorbent assay.

RESULTS

IL-1beta and IL-18 concentrations were higher in the gingival crevicular fluid from periodontitis patients than in that from gingivitis patients; IL-18 concentrations were higher than those of IL-1beta. Very little IL-12, either p40 or p70, was detected in the gingival crevicular fluid samples. In the serum, very low levels of cytokines were found. The level of serum IL-12 p40, however, was higher than in the fluid from periodontitis sites of periodontitis patients.

CONCLUSION

The local production of IL-1beta and IL-18 in the gingival crevicular fluid increased with increasing inflammation and IL-18 was the predominant cytokine at both gingivitis and periodontitis sites. Very little IL-12 was detected with levels decreasing with increasing inflammation. These results suggest that there is an association between severity of periodontal disease and levels of IL-1, IL-12 and IL-18.