Levels of interleukin-1 beta and interleukin-8 in gingival crevicular fluids in adult periodontitis

Proinflammatory gene expression at chronic periodontitis and peri-implantitis sites in patients with or without type 2 diabetes

BACKGROUND

Diabetes and periodontal diseases are often associated. Both have highly inflammatory components, but the role played by distinct phlogistic mediators in their pathogenesis is not fully understood and remains controversial. The purpose of this study is to evaluate whether type 2 diabetes alters the expression of inflammatory mediators in sites with chronic periodontitis (CP) or peri-implantitis (P-IM).

METHODS

The expression of tumor necrosis factor (TNF)-alpha, interleukin (IL)-6 and -8, and monocyte chemotactic protein (MCP)-1 plus key CC chemokine receptors (CCR1 through 5) and CXC chemokine receptors (CXCR1 through 3) was quantified by real-time polymerase chain reaction (PCR) in gingival or peri-implant biopsies from 135 patients with well-controlled or poorly controlled diabetes and periodontal disease, 65 patients with periodontal disease but otherwise healthy, and 90 systematically and periodontally healthy subjects. Western blots were performed.

RESULTS

Relative to controls, in patients without diabetes and patients with well-controlled diabetes, TNF-alpha, CCR5, and CXCR3 expression was exclusively higher in sites with P-IM (P <0.01), whereas IL-6 and -8 were overexpressed in sites with CP and, even more, in sites with P-IM (P <0.01). In patients with poor glycemic control, TNF-alpha, CCR5, and CXCR3 mRNAs were increased in sites with CP (P <0.01). A statistically significant higher IL-6 and -8 expression from patients without diabetes and patients with well-controlled diabetes was observed compared to patients with poorly controlled diabetes. Regardless of metabolic/glycemic status, MCP-1 and CCR2 and 4 were markedly higher in both of the oral pathologies examined (P <0.01). At the protein levels, Western blot experiments confirmed the real-time PCR results.

CONCLUSIONS

These findings showed that: 1) in subjects without diabetes and patients with well-controlled diabetes, TNF-alpha, CCR5, and CXCR3 may constitute distinctive biomarkers of P-IM; 2) poor glycemic control abolished the differences between CP and P-IM regarding the expression of these mediators; and 3) type 2 diabetes affected the expression of TNF-alpha, IL-6 and -8, CCR5, and CXCR3.

The effect of age on the gingival crevicular fluid composition during experimental gingivitis. A pilot study

Background:

Cytokines have been proposed as potentially useful diagnostic or prognostic markers of periodontal inflammation related alterations during the experimental gingivitis model. The role of ageing in periodontal disease needs further elucidation; therefore investigations of its influence on host response are needed.

Objective:

To study the effect of age on interleukins IL -6, IL-8 and TNF-a levels in gingival crevicular fluid (GCF) and their correlations to clinical parameters during experimental gingivitis.

Materials and Methods: Five young subjects (20-22 years old) and five old subjects (61-65 years old), all periodontal healthy, participated in this clinical trial. A professional plaque control programme was undertaken to establish healthy gingival conditions at baseline. Plaque index (PI), gingival index (GI) were recorded at 60 sites at baseline, after 21 days of no oral hygiene and one week later after professional cleaning and reestablishment of oral hygiene procedures. A total of 180 samples were analyzed with ELISA for levels of IL -6, IL-8 and TNF-a in gingival crevicular fluid. The examination included the mesiobuccal sites of the Ramfjord teeth. Comparisons between and within groups were performed by non-parametric tests (Mann- Withney) and correlations were sought for with Wilcoxon test. Significance was set at p=0.05.

Results:

Results showed significant diferences between the two groups with regard to the plaque and bleeding scores and GCF volume, all of which proved to be more pronounced in old group. With respect to laboratory data, mean cytokine concentrations were in general lower in young group. TNF-a had a steady increase for the adults, which was found to be statistically significant between Days 0 and 21, IL-8 showed a statistically significant decrease at Day 28 in the young group and finally IL-6 showed a fluctuation, which was totally adverse for the two groups at each time point.

Conclusion:

Within the limitations of the present study, age cannot be identified as a factor that strongly affects the cytokine expression and fluctuations even in a well-controlled environment of inflammation, such as experimental gingivitis.

Characteristics of inflammation common to both diabetes and periodontitis: are predictive diagnosis and targeted preventive measures possible?

Diabetes and periodontitis are chronic inflammatory disorders that contribute to each others' severity and worsen each others' prognosis. Studies have shown that patients with diabetes are at increased risk of developing periodontitis, and that diabetics with untreated periodontitis have more difficulty controlling serum glucose. Periodontal treatment that reduces gingival inflammation aids in the control of hyperglycemia. Periodontitis is accompanied by gingival bleeding and the production of an inflammatory exudate termed gingival crevicular fluid (GCF) that arises from the inflamed gingival tissues surrounding the teeth. GCF contains byproducts of connective tissue degradation, enzymes from host and bacterial cells, cytokines and other inflammatory mediators, and has been studied for screening blood glucose and for biomarkers of both diabetes and periodontitis. This review focuses on the inter-relationship between diabetes and periodontitis and the biomarkers common to both these diseases that may enable earlier detection, targeted preventive measures and individualized therapeutic intervention of these chronic conditions.

Current developments in salivary diagnostics

Salivary diagnostics is an emerging field that has progressed through several important developments in the past decade, including the publication of the human salivary proteome and the infusion of federal funds to integrate nanotechnologies and microfluidic engineering concepts into developing compact point-of-care devices for rapid analysis of this secretion. In this article, we discuss some of these developments and their relevance to the prognosis, diagnosis and management of periodontitis, as an oral target, and cardiovascular disease, as a systemic example for the potential of these biodiagnostics. Our findings suggest that several biomarkers are associated with distinct biological stages of these diseases and demonstrate promise as practical biomarkers in identifying and managing periodontal disease, and acute myocardial infarction. The majority of these studies have progressed through biomarker discovery, with the identified molecules requiring more robust clinical studies to enable substantive validation for disease diagnosis. It is predicted that with continued advances in this field the use of a combination of biomarkers in multiplex panels is likely to yield accurate screening tools for these diagnoses in the near future.

Irsogladine maleate regulates neutrophil migration and E-cadherin expression in gingival epithelium stimulated by Aggregatibacter actinomycetemcomitans

Irsogladine maleate (IM) counters Aggregatibacter actinomycetemcomitans-induced reduction of the gap junction intercellular communication and the expression of zonula occludens-1, which is a major tight junction structured protein, in cultured human gingival epithelial cells (HGEC). In addition, IM obviates the A. actinomycetemcomitans-induced increase in interleukin (IL)-8 levels in HGEC. Thus, by regulating the intercellular junctional complex and chemokine secretion in HGEC, IM may be useful to prevent periodontal disease. To clarify the effects and regulatory mechanism of IM in vivo and in vitro, we examined the expression of E-cadherin and neutrophil chemotaxis induced by A. actinomycetemcomitans under IM pretreatment. Immunohistochemical studies revealed that A. actinomycetemcomitans application to the gingival sulcus decreased the number of cells positive for E-cadherin and increased those positive for cytokine-induced neutrophil chemoattractant-2alpha (CINC-2alpha) in rat gingival epithelium. However, in IM-pretreated rats, A. actinomycetemcomitans application had little effect on CINC-2alpha and E-cadherin in gingival epithelium. In cultured HGEC, real-time PCR and Western blotting showed that IM and the ERK inhibitor PD98059 abolished the A. actinomycetemcomitans-induced increase in CXCL-1 and IL-8 in HGEC. On the other hand, IM, PD98059, and the p38 MAP kinase inhibitor SB203580 recovered the decrease in E-cadherin expression. In addition, conditioned medium from A. actinomycetemcomitans-stimulated HGEC enhanced human neutrophil chemotaxis, compared to that from un-stimulated HGEC or that from A. actinomycetemcomitans-stimulated HGEC under IM pretreatment. Furthermore, IM down-regulated the p38 MAP kinase and ERK phosphorylations induced by A. actinomycetemcomitans. In conclusion, IM may control A. actinomycetemcomitans-induced gingival inflammation by regulating neutrophil migration and E-cadherin expression in gingival epithelium.

Scavenger receptor A is expressed by macrophages in response to Porphyromonas gingivalis, and participates in TNF-alpha expression

INTRODUCTION

Porphyromonas gingivalis is a periodontopathic bacterium closely associated with generalized aggressive periodontal disease. Pattern recognition receptors (PRRs) participate in host response to this organism. It is likely that PRRs not previously recognized as part of the host response to P. gingivalis also participate in host response to this organism.

METHODS AND RESULTS

Employing qRT-PCR, we observed increased msr1 gene expression at 2, 6, and 24 h of culture with P. gingivalis strain 381. Flow cytometry revealed increased surface expression of SR-A protein by the 24 h time point. Macrophages cultured with an attachment impaired P. gingivalis fimA- mutant (DPG3) expressed intermediate levels of SR-A expression. Heat-killed P. gingivalis stimulated SR-A expression similar to live bacteria, and purified P. gingivalis capsular polysaccharide stimulated macrophage SR-A expression, indicating that live whole organisms are not necessary for SR-A protein expression in macrophage response. As SR-A is known to play a role in lipid uptake by macrophages, we tested the ability of low-density lipoprotein (LDL) to influence the SR-A response of macrophages to P. gingivalis, and observed no effect of LDL on P. gingivalis-elicited SR-A expression. Lastly, we observed that SR-A knockout (SR-A(-/-)) mouse macrophages produced significantly more tumor necrosis factor (TNF)-alpha than wild type mouse macrophages cultured with P. gingivalis.

CONCLUSION

These data identify that SR-A is expressed by macrophages in response to P. gingivalis, and support that this molecule plays a role in TNF-alpha production by macrophages to this organism.

Anti-tumor necrosis factor-alpha therapy and periodontal parameters in patients with rheumatoid arthritis

BACKGROUND

The aim of this study was to evaluate the influence of anti-tumor necrosis factor-alpha (TNF-alpha) therapy on the clinical and immunologic parameters of the periodontium.

METHODS

Ten patients with rheumatoid arthritis (RA) who routinely received infusions of infliximab, 200 mg (RA+), 10 patients with RA without anti-TNF-alpha therapy (RA-), and 10 healthy controls (C) were included. Clinical parameters, including the plaque index (PI), gingival index (GI), probing depth (PD), clinical attachment loss (AL), and bleeding on probing (BOP), were assessed, and total gingival crevicular fluid (GCF) TNF-alpha level was determined using enzyme-linked immunosorbent assay. Analysis of variance with Scheffe modification and the Pearson correlation test were used for statistical analysis.

RESULTS

The ages of the patients ranged from 22 to 76 years (mean, 50.73 +/- 9.1 years). The mean PI was similar among the groups. However, mean inflammatory parameters in the three groups varied significantly; GI was greater in the RA- group compared to RA+ and C groups (P = 0.0042). The RA+ group exhibited less BOP than RA- and C groups (21.1% +/- 3.0%, 45.9% +/- 6.2%, and 39.1% +/- 7.2%, respectively; P = 0.0146). The mean PD in the RA+ group was shallower than in RA- and C groups (3.22 +/- 0.13 mm, 3.85 +/- 0.22 mm, and 3.77 +/- 0.20 mm, respectively; P = 0.055). Clinical AL in the RA+ group was lower than in RA- and C groups (3.68 +/- 0.11 mm, 4.52 +/- 0.26 mm, and 4.35 +/- 0.24 mm, respectively; P = 0.0273). TNF-alpha levels in the GCF of the RA+ group were the lowest compared to RA- and C groups (0.663, 1.23, and 0.949 ng/site, respectively; P = 0.0401). A significant positive correlation was found between TNF-alpha levels in the GCF and clinical AL (r = 0.448; P = 0.0283).

CONCLUSIONS

Patients with RA receiving anti-TNF-alpha medication had lower periodontal indices and GCF TNF-alpha levels. Thus, suppression of proinflammatory cytokines might prove beneficial in suppressing periodontal diseases.

Gingival crevicular fluid MMP-8 and -13 and TIMP-1 levels in patients with rheumatoid arthritis and inflammatory periodontal disease

BACKGROUND

The purpose of this study was to compare gingival crevicular fluid (GCF) levels of matrix metalloproteinase (MMP)-8 and -13 and tissue inhibitor of MMP (TIMP)-1 in patients with rheumatoid arthritis (RA) and systemically healthy counterparts with inflammatory periodontal disease.

METHODS

Subjects (N = 74) were divided into five groups: 12 patients with RA and gingivitis; 13 patients with RA and periodontitis; 12 systemically healthy patients with gingivitis; 13 systemically healthy patients with periodontitis; and 24 periodontally and systemically healthy volunteers. Full-mouth clinical periodontal measurements were performed at six sites/tooth. GCF samples obtained from two sites in single-rooted teeth were analyzed by immunofluorometric assay and enzyme-linked immunosorbent assay. Data were assessed statistically by parametric tests.

RESULTS

The total amounts of MMP-8 were lower in the healthy control group than in RA-gingivitis, RA-periodontitis, and healthy-periodontitis groups (P <0.05). MMP-13 levels were similar in all five study groups (P >0.05). Patients with RA and gingivitis or periodontitis exhibited levels of MMP-8 and -13 and TIMP-1 that were similar to systemically healthy counterparts (P >0.05).

CONCLUSIONS

The coexistence of RA and periodontitis did not significantly affect the investigated parameters. GCF MMP-8 levels increased with periodontal inflammation. Despite the long-term usage of corticosteroids and non-steroidal anti-inflammatory drugs, similar GCF MMP-8 and -13 levels in patients with RA and systemically healthy counterparts suggest that RA may create a tendency to overproduce these enzymes.

Porphyromonas gingivalis mediates the shedding and proteolysis of complement regulatory protein CD46 expressed by oral epithelial cells

INTRODUCTION

Human cells express membrane-bound complement regulatory proteins to prevent complement-mediated autologous tissue damage. In this study, we hypothesized that Porphyromonas gingivalis, the major etiological agent of chronic periodontitis, causes the shedding or proteolysis of the complement regulatory protein CD46 expressed by oral epithelial cells.

METHODS

Oral epithelial cells were treated with a culture of P. gingivalis before measurement of membrane-bound and shed CD46 by enzyme-linked immunosorbent assay (ELISA). The effect of soluble recombinant CD46 on secretion of interleukin-8 (IL-8) by epithelial cells was evaluated by ELISA. The susceptibility of soluble recombinant CD46 to proteolytic degradation by cells and purified Lys-gingipain of P. gingivalis was investigated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/western immunoblotting analysis.

RESULTS

Oral epithelial cells treated with a culture of P. gingivalis showed a lower reactivity with antibodies directed to CD46. ELISA revealed that such a treatment resulted in increased amounts of CD46 in the conditioned media suggesting that P. gingivalis caused the shedding of membrane-anchored CD46. Stimulation of epithelial cells with soluble recombinant CD46 induced IL-8 secretion in a dose-dependent manner. Whole cells and purified Lys-gingipain of P. gingivalis degraded recombinant CD46 in a dose-dependent manner.

CONCLUSION

This study showed the ability of P. gingivalis to induce the shedding/ proteolysis of CD46 from the surface of oral epithelial cells. This may render host cells susceptible to the complement system and contribute to tissue damage and the inflammatory process in periodontitis.

DNA methylation status of the IL8 gene promoter in oral cells of smokers and non-smokers with chronic periodontitis

AIM

This study analysed the status of DNA methylation in the promoter region of the IL8 gene in oral mucosa cells from healthy, smoker and non-smoker subjects with chronic periodontitis and compared these findings among groups with mRNA levels.

MATERIAL AND METHODS

Genomic DNA from epithelial oral cells of 41 healthy subjects, 30 smokers with chronic periodontitis and 40 non-smokers with chronic periodontitis were purified and modified by sodium bisulphite. Genomic DNA from blood leucocytes and gingival cells from biopsies of 13 subjects of each group were also purified and modified by sodium bisulphite. Modified DNA was submitted by methylation-specific polymerase chain reaction (PCR) (MSP), electrophoresed on 10% polyacrylamide gels and stained with SYBR Gold. Total RNA from gingival cells was also isolated using the TRIzol reagent, and real-time PCR performance was used to detect the levels of interleukin-8 mRNA.

RESULTS

Our results indicate that individuals with chronic periodontitis, independent of smoking habit, have a higher percentage of hipomethylation of the IL8 gene than those controls in epithelial oral cells (p<0.0001), and expression of higher levels of interleukin-8 (IL-8) mRNA than controls in gingival cells (p=0.007). No significant differences among groups were observed in gingival cells and blood cells.

CONCLUSION

We conclude that inflammation in the oral mucosa might lead to changes in the DNA methylation status of the IL8 gene in epithelial oral cells.

Thymosin beta4 is cytoprotective in human gingival fibroblasts

Thymosin beta4 (Tbeta(4)) is a naturally occurring, ubiquitous, non-toxic protein with documented wound-healing, anti-inflammatory, anti-apoptotic, and tissue-repair properties in skin, the ocular surface, and the heart. The ability of Tbeta(4) to demonstrate similar protective properties in cells of the oral cavity was analyzed using an in vitro model of cultured human gingival fibroblasts. Thymosin beta 4 significantly suppressed the secretion of interleukin-8 (IL-8) following stimulation with tumor necrosis factoralpha (TNF-alpha), suggesting that it may suppress the inflammatory response initiated by pro-inflammatory cytokines. By contrast, Tbeta(4) was not effective in protecting fibroblasts from challenge with lipopolysaccharide purified from Porphyromonas gingivalis or Escherichia coli. Thymosin beta 4 was able to protect gingival fibroblasts against the known cytotoxic effects of chlorhexidine digluconate, a mouthrinse containing chlorhexidine digluconate, and carbamide peroxide. Additionally, Tbeta(4) was able to protect gingival fibroblasts from the apoptosis that is induced by stimulation with TNF-alpha or by exposure to chlorhexidine. Because of its multifunctional roles in protecting cells against damage, Tbeta(4) may have significant potential for use as an oral heathcare aid with combined antimicrobial, anti-inflammatory, anti-apoptotic, and cytoprotective properties.

Naringenin has anti-inflammatory properties in macrophage and ex vivo human whole-blood models

BACKGROUND AND OBJECTIVE

Periodontitis is a chronic inflammatory disease of bacterial etiology, affecting tooth-supporting tissues. The host inflammatory response to periodontopathogens, notably the high and continuous production of cytokines, is considered a major factor causing the local tissue destruction observed in periodontitis. The aim of the present study was to investigate the effect of naringenin, a major flavanone in grapefruits and tomatoes, on the lipopolysaccharide-induced pro-inflammatory cytokine production by host cells, using two different models.

MATERIAL AND METHODS

The effect of naringenin was characterized using macrophages stimulated with the lipopolysaccharide of either Aggregatibacter actinomycetemcomitans or Escherichia coli and using whole blood stimulated with A. actinomycetemcomitans lipopolysaccharide, in the presence or absence of naringenin. Lipopolysaccharide-induced interleukin-1 beta, interleukin-6, interleukin-8 and tumor necrosis factor-alpha production by macrophages and whole-blood samples treated with naringenin were evaluated using an enzyme-linked immunosorbent assay. Changes in the phosphorylation states of macrophage kinases induced by A. actinomycetemcomitans lipopolysaccharide and naringenin were characterized by immunoblot screening.

RESULTS

Our results clearly indicated that naringenin is a potent inhibitor of the pro-inflammatory cytokine response induced by lipopolysaccharide in both macrophages and in whole blood. Naringenin markedly inhibited the phosphorylation on serines 63 and 73 of Jun proto-oncogene-encoded AP-1 transcription factor in lipopolysaccharide-stimulated macrophages.

CONCLUSION

The results from the present study suggest that naringenin holds promise as a therapeutic agent for treating inflammatory diseases such as periodontitis.

Relationship between the gingival sulcus depth and interleukin-1 isoform concentrations within the adjacent gingival tissue

BACKGROUND AND OBJECTIVE

While there is substantial information concerning the concentrations of interleukin-1 isoforms within gingival crevicular fluid, there is little information concerning their concentrations within either normal or diseased gingival tissues. Therefore, the aim of this study was to evaluate the relationship between the concentrations of gingival interleukin-1 isoforms and the adjacent sulcular depth.

MATERIAL AND METHODS

Interdental gingival papillae were excised and grouped based on adjacent pocket depth and the presence of bleeding on probing. Gingiva adjacent to a sulcus of < or = 3 mm without bleeding on probing were classified as 'normal'; gingiva adjacent to a 3-mm sulcus with bleeding on probing were classified as 'diseased-slight'; gingiva adjacent to a 4-6-mm sulcus featuring bleeding on probing were classified as 'diseased-moderate'; and gingiva adjacent to a sulcus of > 6 mm featuring bleeding on probing were classified as 'diseased-severe'. Tissues were solublized and the concentrations of interleukin-1beta, interleukin-1alpha, interleukin-1 receptor antagonist and interleukin-6 were assessed by enzyme-linked immunosorbent assay. Data were compared by factorial analysis of variance, the post-hoc Tukey test and the Pearson's correlation test.

RESULTS

Gingival concentrations of interleukin-6, interleukin-1 receptor antagonist, interleukin-1alpha- and interleukin-1beta were significantly greater at diseased-severe sites than at normal, diseased-slight, or diseased-moderate sites (p < 0.05); the gingival concentrations of interleukin-1 receptor antagonist and interleukin-1alpha were significantly greater at diseased-severe than at diseased-moderate sites (p < 0.05). Interleukin-1 receptor antagonist concentrations were significantly correlated with both interleukin-1alpha and interleukin-1beta concentrations. The ratios of concentrations of the interleukin-1 isoforms were different at the various stages of inflammation.

CONCLUSION

Our data indicated a progressive increase in gingival concentrations of interleukin-1 isoforms with increased adjacent sulcular depth. However, within 'diseased' tissues, the proportional concentrations of interleukin-1alpha and -beta to interleukin-1 receptor antagonist were lowest within diseased-severe tissues.

Treponema denticola lipooligosaccharide activates gingival fibroblasts and upregulates inflammatory mediator production

In response to bacterial challenges, fibroblasts, a major constituent of gingival connective tissue, can produce immunoregulatory cytokines and proteolytic enzymes that may contribute to tissue destruction and the progression of periodontitis, a chronic inflammatory disease affecting tooth-supporting tissues, including alveolar bone. The spirochete Treponema denticola is a major etiological agent of periodontitis and can invade oral tissues. The aim of the present study was to investigate the inflammatory response of gingival fibroblasts to T. denticola lipooligosaccharide (LOS). T. denticola LOS induced significant production of various inflammatory mediators by fibroblasts, including interleukin-6, interleukin-8, monocyte chemoattractant protein 1, nitric oxide, and prostaglandin E(2). In addition, the secretion of matrix metalloproteinase 3, an enzyme active on basement membrane components, was also significantly increased. The response of fibroblasts was dose-dependent and much stronger following a 24 h stimulation period. The expression and/or phosphorylation state of several signaling proteins, including Fos, MKK1, MKK2, MKK3/6, NF-kappaB p50, and NF-kappaB p65, was enhanced following stimulation of fibroblasts with T. denticola LOS. In summary, T. denticola LOS induced an inflammatory response in gingival fibroblasts and may thus contribute to the immunopathogenesis of periodontitis and the progression of the disease.

Gingival crevicular fluid PGE2, IL-1beta, t-PA, PAI-2 levels in type 2 diabetes and relationship with periodontal disease

OBJECTIVES

To evaluate if type 2 diabetes mellitus increase gingival crevicular fluid (GCF) levels of prostaglandin E(2) (PGE(2)), interleukin-1beta (IL-1beta), tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-2 (PAI-2).

DESIGN AND METHODS

Seventeen type 2 diabetic patients with periodontal disease (DM), 17 otherwise healthy periodontally diseased patients (PD) and 17 systemically and periodontally healthy control subjects (H) were enrolled. Clinical periodontal measurements were recorded at six sites/tooth. GCF samples were analyzed by ELISA. Data were tested by statistical tests.

RESULTS

DM group revealed lower IL-1beta levels than PD group (p<0.01). PGE(2), t-PA and PAI-2 levels were similar in DM and PD groups (p>0.05). PGE(2), t-PA levels were higher in DM and PD groups than H group (p<0.05). PAI-2 level was higher in DM group than H group (p<0.05). GCF total amount of PGE(2) in DM group exhibited significant correlations with all clinical periodontal measurements (p<0.05).

CONCLUSION

Type 2 diabetes in this study seems not to increase GCF levels of the evaluated inflammatory mediators.

Effect of periodontal treatment on IL-1beta, IL-1ra, and IL-10 levels in gingival crevicular fluid in patients with aggressive periodontitis

AIM

The aim of this study was to examine the effect of phase I periodontal treatment on the levels of interleukin (IL)-1beta, IL-1ra, and IL-10 in gingival crevicular fluid (GCF) in patients with generalized aggressive periodontitis (G-AgP).

MATERIAL AND METHODS

Data were obtained from 15 patients with aggressive periodontitis and 15 healthy controls. GCF was collected from at least four pre-selected sites (one shallow, at least two moderate, or at least one deep pockets) in patients with G-AgP. In the healthy group, GCF samples were collected from one site. The cytokine levels were determined by an enzyme-linked immunosorbent assay. Probing depth, clinical attachment level (CAL), gingival and plaque indices, and bleeding on probing were measured. The GCF sampling and clinical measurements were recorded at baseline and 6 weeks later after periodontal treatment.

RESULTS

IL-1beta levels were significantly higher at the moderate and deep pocket sites compared with the shallow sites (p<0.05). After periodontal therapy, IL-1beta levels were significantly reduced in the moderate and deep pocket sites (p<0.05). IL-1ra levels at baseline of the moderate and deep pocket sites were significantly lower than the control sites (p<0.05). IL-10 levels were similar in all pockets and did not change after periodontal therapy.

CONCLUSIONS

The periodontal treatment improves the clinical parameters in G-AgP, and this improvement is evident in deep pocket sites for pocket depth and CAL values. These results confirm that IL-1beta is effective for evaluating the periodontal inflammation and can thus be used as a laboratory tool for assessing the activity of periodontal disease.

Peptostreptococcus micros cell wall elicits a pro-inflammatory response in human macrophages

Peptostreptococcus micros is a Gram-positive anaerobic bacterium associated with periodontitis, a chronic inflammatory disease affecting tooth-supporting tissues. In the present study, we investigated the response of human macrophages to stimulation with a cell wall preparation from P. micros. In addition, the effect of the preparation on the phosphorylation of macrophage kinases was studied. The preparation, which was non-toxic for macrophages, significantly increased the secretion of the pro-inflammatory cytokines TNF-alpha, IL-1beta and IL-6. It also increased the secretion of two potent chemokines IL-8 and, to a lesser extent, RANTES. Lastly, stimulation of macrophages by the P. micros cell wall preparation induced a significant increase in MMP-9 secretion but had no effect on the production of prostaglandin E2. The phosphorylation of macrophage kinases, including cAMP-dependent protein-serine kinase (PKA) catalytic subunit beta, G protein-coupled receptor-serine kinase 2, mitogen-activated protein-serine kinase p38 alpha (p38a MAPK), extracellular regulated protein-serine kinase 2 (ERK2) and Jun N-terminus protein-serine kinases (JNK), increased following stimulation with cell wall. In summary, our study showed that the P. micros cell wall preparation induced intracellular signaling pathways, leading to an increased production of pro-inflammatory cytokines, chemokines and MMP-9 by macrophages.

A p38 mitogen-activated protein kinase inhibitor arrests active alveolar bone loss in a rat periodontitis model

BACKGROUND

Gram-negative bacterial species, such as Actinobacillus actinomycetemcomitans, contain lipopolysaccharide (LPS) that initiates the innate immune system, resulting in inflammatory alveolar bone loss. LPS activates Toll-like receptors on membrane surfaces, stimulating many intracellular signaling cascades, including the p38 mitogen-activated protein kinase (MAPK). Activation of p38 signaling mediates inflammatory cytokine expression, contributing toward osteoclastogenesis and bone loss. The aim of this study was to determine whether the novel, orally active p38 MAPK inhibitor SD282 could arrest progression of LPS-induced alveolar bone destruction in rats.

METHODS

Three groups of female Sprague-Dawley rats received LPS injections to the palatal molar gingiva three times per week for 4 weeks to establish periodontitis. From weeks 5 through 8, two groups received the drug SD282 (N = 14) or 1% polyethylene glycol drug vehicle (N = 14) via oral gavage in addition to LPS injections. The third group continued to receive only LPS injections (N = 8). Microcomputed tomography was used to measure volumetric alveolar bone loss, expressed as bone volume fraction (BVF). Expression of interleukin (IL)-1 and -6 and tumor necrosis factor-alpha (TNF-alpha) was assessed by immunohistochemistry, and osteoclasts were enumerated by tartrate-resistant acid phosphatase staining.

RESULTS

By 4 weeks, severe alveolar bone resorption was seen in LPS-injected animals. Administration of SD282 significantly blocked additional volumetric bone loss in the LPS-only versus LPS + SD282 groups (0.37 +/- 0.01 BVF versus 0.43 +/- 0.01 BVF; P < 0.01). Significant reductions in IL-1beta (P < 0.01 ), TNF-alpha (P < 0.05), and osteoclast formation (P < 0.01) occurred in the presence of SD282.

CONCLUSIONS

An orally active p38 MAPK inhibitor reduced LPS-induced inflammatory cytokine expression, osteoclastogenesis, and alveolar bone loss in rats. Within the limits of the current study, SD282 arrested periodontal disease progression, thus highlighting the therapeutic potential of this novel class of inhibitors.

Cranberry components inhibit interleukin-6, interleukin-8, and prostaglandin E production by lipopolysaccharide-activated gingival fibroblasts

Periodontitis is a chronic inflammatory disease that affects the tooth supporting tissues. Gingival fibroblasts are the most abundant cells in periodontal tissues and participate actively in the host inflammatory response to periodontopathogens, which is known to mediate local tissue destruction in periodontitis. The aim of this study was to investigate the effect of a proanthocyanidin-enriched cranberry fraction, prepared from cranberry juice concentrate, on inflammatory mediator production by gingival fibroblasts stimulated by the lipopolysaccharide (LPS) of Aggregatibacter actinomycetemcomitans. Interleukin (IL)-6, IL-8, and prostaglandin E(2) (PGE(2)) production by fibroblasts treated with the cranberry fraction and stimulated by A. actinomycetemcomitans LPS was evaluated by enzyme-linked immunosorbent assay. Changes induced by A. actinomycetemcomitans LPS and the cranberry fraction in the expression and phosphorylation state of fibroblast intracellular signaling proteins were characterized by antibody microarrays. The LPS-induced IL-6, IL-8, and PGE(2) responses of gingival fibroblasts were inhibited by treatment with the cranberry fraction. This fraction was found to inhibit fibroblast intracellular signaling proteins, a phenomenon that may lead to a down-regulation of activating protein-1 activity. Cranberry components also reduced cyclooxygenase 2 expression. This study suggests that cranberry juice contains molecules with interesting properties for the development of new host-modulating therapeutic strategies in the adjunctive treatment of periodontitis.

Actinobacillus actinomycetemcomitans lipopolysaccharide-mediated experimental bone loss model for aggressive periodontitis

BACKGROUND

Bacterial constituents, such as Gram-negative derived lipopolysaccharide (LPS), can initiate inflammatory bone loss through induction of host-derived inflammatory cytokines. The aim of this study was to establish a model of aggressive inflammatory alveolar bone loss in rats using LPS derived from the periodontal pathogen Actinobacillus actinomycetemcomitans.

METHODS

Eighteen female Sprague-Dawley rats were divided into LPS test (N = 12) and saline control (N = 6) groups. All animals received injections to the palatal molar gingiva three times per week for 8 weeks. At 8 weeks, linear and volumetric alveolar bone loss was measured by micro-computed tomography (microCT). The prevalence of inflammatory infiltrate, proinflammatory cytokines, and osteoclasts was assessed from hematoxylin and eosin, immunohistochemical, or tartrate-resistant acid phosphatase (TRAP)-stained sections. Statistical analysis was performed.

RESULTS

A. actinomycetemcomitans LPS induced severe bone loss over 8 weeks, whereas control groups were unchanged. Linear and volumetric analysis of maxillae by microCT indicated significant loss of bone with LPS administration. Histologic examination revealed increased inflammatory infiltrate, significantly increased immunostaining for interleukin IL-6 and -1beta and tumor necrosis factor-alpha, and more TRAP-positive osteoclasts in the LPS group compared to controls.

CONCLUSION

Oral injections of LPS derived from the periodontal pathogen A. actinomycetemcomitans can induce severe alveolar bone loss and proinflammatory cytokine production in rats by 8 weeks.

Gingival crevicular fluid matrix metalloproteinase (MMP)-7, extracellular MMP inducer, and tissue inhibitor of MMP-1 levels in periodontal disease

BACKGROUND

During periodontal inflammation, matrix metalloproteinases (MMPs) are under the control of several regulatory mechanisms including the upregulation of expression by inducers and downregulation by inhibitors. Our study aimed to examine the levels and molecular forms of MMP-7, tissue inhibitor of MMP (TIMP)-1, and extracellular matrix metalloproteinase inducer (EMMPRIN) in gingival crevicular fluid (GCF) from patients with different periodontal diseases.

METHODS

A total of 80 subjects (20 patients with generalized aggressive periodontitis [GAgP], 20 with chronic periodontitis [CP], 20 with gingivitis, and 20 periodontally healthy subjects) were included in this study. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, presence of bleeding on probing, and plaque. GCF MMP-7, TIMP-1, and EMMPRIN levels and molecular forms were analyzed by enzyme-linked immunosorbent assay (ELISA) and Western immunoblot techniques using specific antibodies.

RESULTS

Total amounts of GCF MMP-7 were found to be similar between the study groups. GAgP, CP, and gingivitis groups had significantly higher total amounts of GCF EMMPRIN compared to healthy subjects (P <0.008). Among the patient groups, the GAgP group had the highest total amount of GCF EMMPRIN relative to the gingivitis group (P = 0.0004). Soluble EMMPRIN existed in GCF in multiple molecular-weight species especially in periodontitis-affected GCF under non-reducing conditions, i.e., 30-, 55-, 100-, 180-, and 200-kDa species. All patient groups had significantly elevated total amounts of GCF TIMP-1 relative to the healthy group (P <0.0001). GAgP and CP groups also had a higher total amount of GCF TIMP-1 compared to the gingivitis group (P <0.0001 and P <0.0001, respectively). The GAgP group had higher GCF TIMP-1 and EMMPRIN levels compared to the CP group, but this elevation did not reach statistical significance.

CONCLUSIONS

Our data indicate that MMP-7 is associated with the innate host defense in periodontal tissues. Increased EMMPRIN and TIMP-1 levels in GCF are associated with the enhanced severity of periodontal inflammation, indicating that these molecules can participate in the regulation of progression of periodontal diseases. To our knowledge, the present study demonstrated the presence of soluble forms of EMMPRIN in GCF of patients with different periodontal diseases for the first time.

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.

Muscarinic cholinoceptor activation modulates DNA synthesis and CD40 expression in fibroblast cells

1 The aim of the present work was to examine the role of muscarinic acetylcholine receptors (mAChR) on DNA synthesis and CD40 expression in human fibroblast cells. Neonatal human skin fibroblast cultures were stimulated with carbachol in presence or absence of specific antagonists and the following parameters were measured: identification of mAChR subtypes, DNA synthesis, inositol phosphates (InsP) production and CD40 expression. 2 Human fibroblasts express mAChR with Kd 0.47 +/- 0.11 nm and Bmax 236 +/- 22 fmol mg protein(-1). Carbachol stimulates DNA synthesis, InsP and the expression of CD40. All these effects were inhibited by atropine, mustard hydrochloride (4-DAMP) and pirenzepine but not by AF-DX 116 and tropicamide, indicating that M3 and M1 mAChR are implicated in carbachol action. The relative Ki of the antagonists obtained by competition binding assay was in parallel to the relative potency for blocking both carbachol-stimulated InsP accumulation and DNA synthesis. 3 The intracellular pathway leading to carbachol-induced biological effects involved phospholipase C and calcium/calmodulin, as U-73122 and trifluoroperazine blocked carbachol effects, respectively. Calphostin C, a protein kinase C inhibitor, had no effect, indicating that this enzyme does not participate in the system. 4 These results may contribute to a better understanding of the modulatory role of the parasympathetic muscarinic system on normal human fibroblast function.

A p38alpha selective mitogen-activated protein kinase inhibitor prevents periodontal bone loss

In the oral microbial environment, Gram-negative bacterial derived lipopolysaccharide (LPS) can initiate inflammatory bone loss as seen in periodontal diseases. p38 Mitogen-activated protein kinase (MAPK) signaling is critical to inflammatory cytokine and LPS-induced cytokine expression, which may contribute toward periodontal bone loss. The purpose of this proof-of-principle study was to evaluate the ability of an orally active p38alpha MAPK inhibitor (SD-282) to reduce periopathogenic LPS-induced alveolar bone loss in an experimental rat model. Five groups of Sprague-Dawley rats received one of the following treatments: LPS injected to the palatal gingiva adjacent to the maxillary molars three times per week for 8 weeks, LPS plus two doses of SD-282 (15 or 45 mg/kg) twice daily by oral gavage, or control groups given drug vehicle (1% polyethylene glycol) or SD-282 (45 mg/kg) only. Baseline and 8-week alveolar bone loss was assessed by microcomputed tomography (microCT) and histological examination. LPS induced severe bone loss over this time period, whereas control groups were unchanged from baseline measurements. Both doses of SD-282 showed significant protection from LPS-induced bone loss. Bone area and volumetric analysis of maxillas by microCT indicated significant loss of bone volume with LPS treatment, which was blocked with the p38 inhibitor. Histological examination indicated significantly fewer tartate-resistant acid phosphatase-positive osteoclasts and a significant decrease in interleukin (IL)-6, IL-1beta, and tumor necrosis factor alpha expression in p38 inhibitor-treated groups compared with LPS groups by immunostaining. Results from this in vivo study suggest that orally active p38 MAPK inhibitors can reduce LPS-induced inflammatory cytokine production and osteoclast formation and protect against LPS-stimulated alveolar bone loss.

Gingival crevicular fluid transforming growth factor-β1 in several forms of periodontal disease

BACKGROUND

Transforming growth factor-beta(1) (TGF-beta(1)) has significant effects on periodontal host response regulation. Limited knowledge on the role of TGF-beta(1) in various periodontal disease types and particularly in advanced periodontitis forms warranted the present study. The aim of the present study was to evaluate the gingival crevicular fluid (GCF) TGF-beta(1) levels in patients with different forms of periodontal disease.

METHODS

GCF TGF-beta(1) levels were investigated in 32 chronic periodontitis (CP), 30 generalized aggressive periodontitis (G-AgP), 15 gingivitis patients and 16 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, plaque and bleeding on probing. TGF-beta(1) levels were analyzed by enzyme-linked immunosorbent assay. The results were expressed in terms of total amount (pg) and concentration (pg/microl).

RESULTS

G-AgP and CP groups had significantly elevated GCF TGF-beta(1) total amount compared to healthy group (p<0.008). Moreover, GCF TGF-beta(1) total amount of G-AgP group was significantly higher than that of gingivitis group (p<0.008). G-AgP and CP groups had similar GCF TGF-beta(1) total amount (p>0.008). Significant correlation was found between GCF TGF-beta(1) total amount and all clinical periodontal parameters (p<0.05).

CONCLUSIONS

The results of the present study suggest contribution of TGF-beta(1) to the pathogenesis of advanced chronic and aggressive periodontitis. TGF-beta(1) may thus be one of the components modulating exaggerated host response together with other major mediators of inflammation.

Production of interleukin-8 in vitro by mononuclear cells isolated from human periapical lesions

INTRODUCTION

Interleukin-8 (IL-8) is an important mediator of inflammation. However, little is known about its production in chronic dental periapical lesions and this was the main aim of this work.

METHODS

Inflammatory cells were isolated from clinically different periapical lesions and analyzed by morphological criteria. The mononuclear cells were isolated, phenotypically analyzed by immunocytochemistry and cultivated in vitro. IL-8 was measured in culture supernatants of these periapical lesion mononuclear cells (PL-MNC) using a microbeads fluorescence assay.

RESULTS

We found a relatively high production of IL-8 in 19 out of 21 periapical lesions included in the study. The level of IL-8 and the proportion of neutrophil granulocytes were significantly higher in the group of symptomatic lesions, compared to the asymptomatic lesions, but there was no statistically significant correlation between these parameters. According to the predominance of CD3(+) T cells and Ig(+)/CD19(+) B cells and plasma cells, lesions were divided into T-type and B-type lesions, respectively. The levels of IL-8 were significantly higher in the culture supernatants of PL-MNC in the T-type lesions and were positively correlated with the proportion of macrophages/dendritic cells (CD11c(+) cells) and CD4(+) T cells. Such a correlation was not shown in B-type lesions.

CONCLUSION

These results suggest that PL-MNC are a significant source of IL-8, which is probably an important chemokine for the migration and function of different cell types at the site of chronic inflammation.

Innate immune signaling and Porphyromonas gingivalis-accelerated atherosclerosis

Periodontal diseases are a group of diseases that lead to erosion of the hard and soft tissues of the periodontium, which, in severe cases, can result in tooth loss. Anecdotal clinical observations have suggested that poor oral health may be associated with poor systemic health; however, only recently have appropriate epidemiological studies been initiated, with defined clinical endpoints of periodontal disease, to address the association of periodontal disease with increased risk for cardiovascular and cerebrovascular disease. Although conflicting reports exist, these epidemiological studies support this connection. Paralleling these epidemiological studies, emerging basic scientific studies also support that infection may represent a risk factor for atherosclerosis. With P. gingivalis as a model pathogen, in vitro studies support that this organism can activate host innate immune responses associated with atherosclerosis, and in vivo studies demonstrate that this organism can accelerate atheroma deposition in animal models. In this review, we focus primarily on the basic scientific studies performed to date which support that infection with bacteria, most notably P. gingivalis, accelerates atherosclerosis. Furthermore, we attempt to bring together these studies to provide an up-to-date framework of emerging theories into the mechanisms underlying periodontal disease and increased risk for atherosclerosis, as well as identify intervention strategies to reduce the incidence of periodontal disease in humans, in an attempt to decrease risk for systemic complications of periodontal disease such as atherosclerotic cardiovascular disease.

The K1 serotype capsular polysaccharide of Porphyromonas gingivalis elicits chemokine production from murine macrophages that facilitates cell migration

Porphyromonas gingivalis is the principal organism associated with aggressive forms of generalized periodontal disease. Previous reports have suggested that encapsulated P. gingivalis strains are more virulent than unencapsulated strains; however, the contribution of capsular polysaccharide (CPS) to the virulence of this organism is poorly understood. Since periodontal disease presents with a complex inflammatory cell lesion comprised of neutrophils and monocytes, we cultured murine peritoneal macrophages with heat-killed P. gingivalis W83, CPS purified from P. gingivalis strain W83, and the seven known serotype-specific P. gingivalis CPS and assessed the ability of supernatant fluids produced by challenged macrophages to attract naïve inflammatory cells. We also defined JE/MCP-1, KC, MIP-2, and RANTES production in response to the P. gingivalis CPS antigens. We observed that supernatant fluids collected from macrophages incubated with P. gingivalis W83 and serotype K1 CPS stimulated the migration of naïve murine bone marrow-derived polymorphonuclear leukocytes in an in vitro cell migration chamber. CPS from W83 and the K1 serotype elicited potent chemokine secretion patterns for macrophages, while those specific to serotypes K2 to K7 were significantly less stimulatory. Reverse transcription-PCR and enzyme-linked immunosorbent assay revealed JE/MCP-1, KC, MIP-2, and RANTES expression from murine macrophages which had been challenged with purified P. gingivalis W83 CPS. Chemokine production appeared to be dependent on both the dose of and time of exposure to P. gingivalis W83 CPS. These data demonstrate that the P. gingivalis serotype K1 CPS elicits chemokine production from phagocytic cells. Furthermore, these data suggest that the host response to this antigen may contribute to the formation of the inflammatory cell lesion observed during P. gingivalis-elicited periodontal disease.

Gingival crevicular fluid laminin-5 gamma2-chain levels in periodontal disease

AIM

Our study aimed to examine the molecular forms and gingival crevicular fluid (GCF) levels of laminin-5 gamma2-chain in patients with different periodontal disease, and compare the effects of P.gingivalis trypsin-like proteinase on intact laminin-5 gamma2-chain species.

METHODS

Eighteen patients with generalized aggressive periodontitis (G-AgP), 29 patients with chronic periodontitis (CP), 20 with gingivitis and 20 periodontally healthy subjects were included. Probing depth, clinical attachment loss, presence of bleeding on probing and plaque were recorded. Molecular forms and GCF laminin-5 gamma2-chain levels and the effects of P. gingivalis trypsin-like proteinase on intact laminin-5 gamma2-chain were analysed by computer-quantitated Western immunoblotting.

RESULTS

Laminin-5 gamma2-chain 40 and 70 kDa fragments could be detected in all groups, in varying levels. The CP group had elevated GCF laminin-5 gamma2-chain fragment levels compared with the gingivitis and healthy groups (p<0.008). The G-AgP group had GCF laminin-5 gamma2-chain fragment levels similar to the gingivitis and healthy groups (p>0.008). GCF laminin-5 gamma2-chain fragments differed clearly from the multiple lower molecular size fragments of P.gingivalis trypsin-laminin-5 gamma2-chain proteinases.

CONCLUSION

Increased GCF laminin-5 gamma2-chain fragments in periodontitis sites with deep periodontal pocket suggest that these cleaved 40 and 70 kDa fragments could reflect the extent of the inflammatory reaction in CP.

The influence of diabetes on gingival crevicular fluid beta-glucuronidase and interleukin-8

OBJECTIVES

Polymorphonuclear neutrophil (PMN) dysfunction is associated with diabetes. We examined the gingival crevicular fluid (GCF) beta-glucuronidase (BG) and interleukin-8 (IL-8) levels of periodontitis patients with and without type 2 diabetes mellitus (DM).

MATERIAL AND METHODS

Forty five adults with type 2 DM and 32 adults without DM, both with chronic periodontitis were enrolled. GCF was collected from eight posterior sites in each quadrant, and periodontal parameters were recorded. GCF was assayed for IL-8 by ELISA and BG by a fluorometric assay.

RESULTS

GCF IL-8 was positively correlated with probing depth (PD), and GCF BG but not clinical attachment level (CAL), bleeding on probing (BOP), or plaque index (PI). In contrast, GCF BG was strongly correlated with each of the clinical measures of periodontal disease. Subjects with DM significantly lower levels of both BG (73.0+/-44.8 versus 121.9+/-84.6 pg/sample; p=0.002) and IL-8 (32.1+/-33.1 versus 90.8+/-83.2 pg/sample; p<0.0001) even after adjustments for age, gender, PD, CAL, BOP, and PI. Neither BG nor IL-8 was correlated with HbA1c levels in subjects with DM.

CONCLUSION

These data suggest that an inadequate local response by PMN, partially explained by an altered chemokine gradient, may contribute to periodontal disease in patients with type 2 DM.

Novel rinse assay for the quantification of oral neutrophils and the monitoring of chronic periodontal disease

BACKGROUND AND OBJECTIVES

The aim of this study was to develop a single, rapid, noninvasive oral rinse assay to enable the accurate quantification of oral neutrophils. Products released by neutrophils are partly responsible for the destruction observed in periodontitis. Quantification of oral neutrophil levels is important for understanding their role in periodontal diseases. Previous studies have relied on time-consuming serial rinses and cumbersome counting techniques for the collection and quantification of oral neutrophils.

MATERIAL AND METHODS

Patients with chronic periodontal disease provided rinse samples before and after phase I periodontal treatment. Cells in the rinse samples were stained with acridine orange, and neutrophil counts were carried out using a fluorescence microscope and a hemocytometer.

RESULTS

This assay allowed us to detect a significant difference in pretreatment oral neutrophil counts between periodontal disease and healthy control groups (p < 0.001). Patients who responded favorably to phase I therapy demonstrated a 43% reduction in oral neutrophil counts compared with their pretreatment levels (p = 0.019). Patients who did not respond to phase I periodontal treatment showed no significant difference in oral neutrophil levels (p = 0.39).

CONCLUSION

Oral neutrophil levels, as determined by a rapid oral rinse, reflect the severity of periodontal disease and treatment response. A single, rapid, oral rinse assay is an effective means of collecting and quantifying oral neutrophil levels and may serve as an excellent research tool for further study of the role of neutrophils in periodontal diseases.

Salivary biomarkers of existing periodontal disease: a cross-sectional study

BACKGROUND

The authors conducted a study to determine if salivary biomarkers specific for three aspects of periodontitis--inflammation, collagen degradation and bone turnover--correlate with clinica features of periodontal disease.

METHODS

The relationship between periodontal disease and the levels of interleukin-1 beta (IL-1beta), matrix metalloproteinase (MMP)-8, and osteoprotegerin (OPG) in whole saliva of 57 adults (28 "case" subjects with moderate-to-severe periodontal disease and 29 healthy control subjects) was examined in a case-control trial.

RESULTS

Mean levels of IL-1beta and MMP-8 in saliva were significantly higher in case subjects than in controls. Both analytes correlated with periodontal indexes, whereas, after adjustment for confounders, OPG did not. Elevated salivary levels of MMP-8 or IL-1beta (more than two standard deviations above the mean of the controls) significantly increased the risk of periodontal disease (odds ratios in the 11.3-15.4 range). Combined elevated salivary levels of MMP-8 and IL-1beta increased the risk of experiencing periodontal disease 45-fold, and elevations in all three biomarkers correlated with individual clinical parameters indicative of periodontal disease.

CONCLUSION

Salivary levels of MMP-8 and IL-1beta appear to serve as biomarkers of periodontitis.

CLINICAL IMPLICATIONS

Qualitative changes in the composition of salivary biomarkers could have significance in the diagnosis and treatment of periodontal disease.

Epidermal growth factor synergistically enhances interleukin-8 production in human gingival fibroblasts stimulated with interleukin-1beta

The chemokine interleukin-8 (IL-8) has been implicated in inflammatory diseases including periodontitis. In this study the effect of epidermal growth factor (EGF) on the production and regulation of interleukin-8 (IL-8) in human gingival fibroblasts challenged with interleukin-1beta (IL-1beta) was investigated. EGF, in comparison to the effect of IL-1beta, weakly increased the mRNA and protein expression of IL-8 in gingival fibroblasts. When the cells were treated simultaneously with EGF and IL-1beta, however, EGF synergistically enhanced the mRNA expression and production of IL-8. The stimulatory effect of EGF on IL-1beta-induced IL-8 production was completely abolished by the broad range tyrosine kinase inhibitor Herbimycin A, and considerably reduced by the receptor tyrosine kinase specific inhibitor PD 153035. Herbimycin A abolished IL-8 production induced by IL-1beta, whereas PD 153035 had no effect on the cytokine-induced IL-8 production. Furthermore, the p38 mitogen-activated protein (MAP) kinase inhibitor SB 203580 reduced IL-8 production induced by IL-1beta as well as by the combination of EGF and IL-1beta but had no effect on EGF-induced IL-8 production. In conclusion, the study demonstrates that EGF synergistically stimulates IL-8 production in the presence of IL-1beta and that tyrosine kinase(s) seem to be involved in the signalling pathway of IL-1beta and EGF. The synergistic interactions between EGF and IL-1beta on IL-8 production may play an essential role in the pathogenesis of the inflammatory disease periodontitis.

Imbalance between soluble tumour necrosis factor receptors type 1 and 2 in chronic periodontitis

BACKGROUND

Soluble types of tumour necrosis factor (TNF) receptors type 1 and 2 modulate the TNF-alpha-mediated inflammatory responses in chronic periodontitis (CP).

OBJECTIVES

This study investigated the levels of TNF-alpha, soluble TNF receptor type 1 and 2 in gingival crevicular fluid (GCF) and serum of healthy subjects and CP patients.

MATERIALS AND METHODS

Thirty-eight sera and 73 GCF samples were collected from 16 healthy subjects and 22 CP patients. GCF was collected from probing pocket depth (PPD)< or =3 mm sites of healthy subjects, PPD< or =3, 4-6 and > or =7 mm sites of CP patients. The levels of TNF-alpha, soluble TNF receptor type 1 and 2 in the serum and GCF were quantified by enzyme-linked immunosorbant assay.

RESULTS

The total amounts of TNF-alpha, soluble TNF receptor type 1 and 2 in GCF significantly elevated with increasing PPD in both site-based (p<0.05) and subject-based (p<0.05) analyses. However, their levels progressively diverged as the pocket depths increased, with the soluble TNF receptor type 2 level being comparatively lower than type 1. On the other hand, soluble TNF receptor type 2/type 1 ratios in GCF decreased as the severity of periodontitis increased (p<0.0001).

CONCLUSION

The imbalance between soluble TNF receptor type 1 and 2 levels in GCF could be related to CP severity.

Actinobacillus actinomycetemcomitans Y4 capsular polysaccharide induces IL-1beta mRNA expression through the JNK pathway in differentiated THP-1 cells

Capsular polysaccharide from Actinobacillus actinomycetemcomitans Y4 (Y4 CP) induces bone resorption in a mouse organ culture system and osteoclast formation in mouse bone marrow cultures, as reported in previous studies. We also found that Y4 CP inhibits the release of interleukin (IL)-6 and IL-8 from human gingival fibroblast (HGF). Thus Y4 CP induces various responses in localized tissue and leads to the secretion of several cytokines. However, the effects of Y4 CP on human monocytes/macrophages are still unclear. In this study, THP-1 cells, which are a human monocytic cell line, were stimulated with Y4 CP, and we measured gene expression in inflammatory cytokine and signal transduction pathways. IL-1beta and tumour necrosis factor (TNF)-alpha mRNA were induced from Y4 CP-treated THP-1 cells. IL-1beta mRNA expression was increased according to the dose of Y4 CP, and in a time-dependent manner. IL-1beta mRNA expression induced by Y4 CP (100 microg/ml) was approximately 7- to 10-fold greater than that in the control by real-time PCR analysis. Furthermore, neither PD98059, a specific inhibitor of extracellular signal-regulated kinase nor SB203580, a specific inhibitor of p38 kinase prevented the IL-1beta expression induced by Y4 CP. However, JNK Inhibitor II, a specific inhibitor of c-Jun N-terminal kinase (JNK) prevented the IL-1beta mRNA expression induced by Y4 CP in a concentration-dependent manner. These results indicate that Y4 CP-mediated JNK pathways play an important role in the regulation of IL-1beta mRNA. Therefore, Y4 CP-transduced signals for IL-1beta induction in the antibacterial action of macrophages may provide a therapeutic strategy for periodontitis.

Bradykinin upregulates IL-8 production in human gingival fibroblasts stimulated by interleukin-1beta and tumor necrosis factor alpha

The proinflammatory mediator bradykinin (BK) is suggested to play an important role in the pathogenesis of various inflammatory diseases including periodontitis. In this study, BK per se stimulated interleukin-8 (IL-8) production in human gingival fibroblasts in vitro. Furthermore, BK upregulated the stimulatory effect of the cytokines IL-1beta and TNFalpha on the production of IL-8. The stimulatory effect of BK on the IL-1beta- or TNFalpha-stimulated IL-8 production was reduced in the presence of BK B2 receptor antagonist HOE 140, whereas the B1 receptor antagonist Lys-(des-arg9, Leu8)-BK had no effect. Similar to BK, the calcium ionophore A23187 also upregulated the stimulatory effect of IL-1beta and TNFalpha on IL-8 production. The protein kinase C (PKC) inhibitor bisindolylmaleimide, BIS, significantly reduced the stimulatory effect of BK on IL-1beta and TNFalpha increased IL-8 production but did not affect the production of IL-8 stimulated by cytokines alone. The specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB 203580 reduced IL-8 production stimulated by the combination of BK and IL-1beta as well as the IL-1beta-stimulated IL-8 production. In conclusion, this study shows that BK upregulates IL-1beta- and TNFalpha-stimulated IL-8 production via BK B2 receptor and that PKC signal pathway seems to be involved in the upregulation of the cytokine-induced IL-8 production in gingival fibroblasts. This stimulatory effect of BK on IL-8 production may contribute to the maintenance of the gingival inflammation and enhanced risk for destruction of gingival connective tissue.

Effect of periodontal therapy on crevicular fluid interleukin-1beta and interleukin-10 levels in chronic periodontitis

OBJECTIVES

This study aimed to analyse the levels of the proinflammatory cytokine IL-1beta and the anti-inflammatory cytokine IL-10 in gingival crevicular fluid (GCF) of patients with chronic periodontitis prior to, and following, periodontal therapy for a period of 32 weeks.

MATERIAL AND METHODS

GCF samples were obtained from 24 non-diseased and 72 diseased sites of 12 periodontal patients prior to as well as at 6, 16 and 32 weeks post-periodontal therapy. All sites received conventional periodontal treatment and IL-1beta and IL-10 levels (concentration and total amount) were determined by enzyme linked immunosorbent assay (ELISA). Additionally, probing pocket depth (PD), clinical attachment loss (CAL), gingival (GI) and plaque (PII) indices were evaluated pre-and post-therapy.

RESULTS

IL-1beta was detected in 382 out of 384 samples, while IL-10 was detected in 337 out of 384 samples. The total amount of IL-1beta was significantly higher at diseased compared to non-diseased sites (p<0.01). Following therapy, IL-1beta total amounts were reduced, while IL-1beta concentration gradually increased. IL-10 total amounts (per 30 s sample) were similar in diseased and non-diseased sites, and following therapy they remained almost unchanged. By contrast, IL-10 concentration was significantly higher in non-diseased sites (p<0.01) and displayed a significant increase post-therapy. Moreover, IL-1beta concentration and total amount were significantly greater in smokers following therapy, while IL-10 total amount was significantly higher in non-smokers both prior to and following therapy. Total IL-1beta amounts were positively correlated with GI and Pll. A weak negative correlation between IL-1beta and IL-10 levels was noted (p<0.05).

CONCLUSIONS

The data suggest that the total amount rather than the concentration of IL-1beta in GCF seemed to be closely associated with periodontal disease severity. Moreover, smoking status influenced IL-1beta and IL-10 levels. An inverse relationship between IL-1beta and IL-10 was evident.

Gingival crevicular fluid monocyte chemoattractant protein-1 and RANTES levels in patients with generalized aggressive periodontitis

BACKGROUND

Local and systemic inflammatory and immune mechanisms may be implicated in the pathogenesis of the aggressive forms of periodontal disease. Chemokines, monocyte chemoattractant protein-1 (MCP-1) and regulated on activation, normal T cells expressed and secreted RANTES (regulated on activation, normal T cells expressed and secreted), are involved in the activation and recruitment of inflammatory and immune cells to the infected sites and thereby mediating a variety of pathophysiological conditions. The aim of the present study was to examine the gingival crevicular fluid (GCF) levels of MCP-1 and RANTES in patients with generalized agressive periodontitis (G-AgP).

METHODS

MCP-1 and RANTES levels were investigated in GCF samples of 10 patients with G-AgP and 10 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, presence of bleeding on probing and plaque. In the G-AgP group, GCF samples were collected from the two approximal sites; from one single-rooted tooth and from one first molar tooth with > or =6 mm probing depth. In the healthy group, GCF samples were collected from one of the single-rooted teeth. GCF MCP-1 and RANTES levels were quantified by enzyme immunoassay.

RESULTS

The G-AgP patients had significantly higher GCF MCP-1 and RANTES levels compared to the healthy group (p<0.05). GCF MCP-1 and RANTES levels were positively correlated with both probing depth and clinical attachment loss (p<0.05). There was no correlation between GCF MCP-1 and RANTES levels and the percentage of sites with bleeding (p>0.05).

CONCLUSIONS

The results of the present study suggest that MCP-1 and RANTES could play key roles in both activation and recruitment of inflammatory and immune cells in periodontal environment of G-AgP patients. In conclusion, these CC chemokines may be considered in the biological mechanism underlying the pathogenesis and progression of G-AgP.

Cytokine profile in gingival crevicular fluid of aggressive periodontitis: influence of smoking and stress

BACKGROUND

Cigarette smoking and stress are considered risk factors that have been associated with periodontal disease progression. Conflicting results have been reported concerning the direct influence of smoking on the subgingival microbiota of periodontitis patients. Cytokine production may also be influenced by smoking and stress leading to an imbalance that disturbs the host-parasite relationship.

AIM

The objective of the present study was to evaluate the influence of cigarette smoking on the gingival crevicular fluid (GCF) levels of interleukin (IL)-1beta, IL-4, IL-6 and IL-8 in aggressive or early onset periodontitis (EOP) patients and in healthy controls (H), psychosocial stress being considered as modifying factor.

MATERIAL AND METHODS

Sixty-five EOP and 35 periodontally healthy individuals participated in this cross-sectional study. All the participants were interviewed about their smoking habits and their stressful social events. Clinical examination included the assessment of plaque index (PI), bleeding on probing (BOP), clinical attachment level (CAL) and probing pocket depth (PPD). GCF was collected using durapore strips, from four sites per patient, randomly selected in each quadrant. The total amounts of IL-1beta, IL-4, IL-6 and IL-8 were measured in a total of 400 samples using commercially available enzyme-linked immunosorbent assays.

RESULTS

All clinical parameters were significantly higher in the EOP group compared to the H group. There were no significant differences between EOP smokers and EOP non-smokers with regard to plaque accumulation, CAL and PPD of the sampling sites, whereas mean CAL and PPD of the diseased sites were greater in EOP smokers than in EOP non-smokers. In addition, EOP smokers seemed to have significantly less BOP and greater bone loss compared to EOP non-smokers. Significant interactions between "EOP" and "smoking" were present for total amounts of IL-1beta and IL-4. IL-1beta, IL-6 and IL-8 showed significant main effects with healthy smokers and healthy non-smokers, respectively. For IL-8, stress presented a statistically significant interaction with smoking status and EOP (F=4.742, p=0.030). More specifically EOP smokers were statistically affected by stress.

CONCLUSIONS

Smoking influences host-related factors including cytokine network. The relative importance of smoking and stress-related alterations and their precise mode of action in increasing the risk of aggressive periodontitis remains to be elucidated.

In vitro models of tissue penetration and destruction by Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative anaerobic bacterium that is considered the key etiologic agent of chronic periodontitis. Arg- and Lys-gingipain cysteine proteinases produced by P. gingivalis are key virulence factors and are believed to be essential for significant tissue component degradation, leading to host tissue invasion by periodontopathogens. Two in vitro models were used to determine the extent to which P. gingivalis can reach connective tissue. The tissue penetration potential of P. gingivalis was first investigated by using an engineered human oral mucosa model composed of normal human epithelial cells and fibroblasts. Internalized bacteria were assessed by transmission electron microscopy. Bacteria were observed within multilayered gingival epithelial cells and in the space between the stratified epithelium and the lamina propria. A gingipain-null mutant strain of P. gingivalis was found to be less potent in penetrating tissue than the wild-type strain. Proinflammatory responses to P. gingivalis infection were evaluated. P. gingivalis increased the secretion of interleukin-1 beta, interleukin-6, interleukin-8, and tumor necrosis factor alpha. In the second part of the study, the contribution of P. gingivalis gingipains to tissue penetration was investigated by using a reconstituted basement membrane model (Matrigel). The penetration of (14)C-labeled P. gingivalis cells through Matrigel was significantly reduced when leupeptin, a specific inhibitor of Arg-gingipain activity, was added or when a gingipain-null mutant was used. The results obtained with these two relevant models support the capacities of P. gingivalis to infiltrate periodontal tissue and to modulate the proinflammatory response and suggest a critical role of gingipains in tissue destruction.