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

Advances in periodontal disease markers

A computer-assisted medline search was conducted to find the relevant articles concerning the periodontal disease markers in gingival crevicular fluid (GCF) and saliva published during the 10-year period from 1993 to July 2003. This review suggests that certain diagnostic uses of saliva and GCF show promise. Although both fluids have been used to evaluate the risk for an individual to develop periodontal disease and to monitor of the host response to periodontal therapy, GCF has the chance of being closely approximated to the periodontal tissues where periodontal disease begins. The enzymes contributed to extracellular matrix (ECM) molecules and non-ECM molecules degradation and markers for polymorphonuclear leukocytes (PMN) activity and influx into the gingival tissue seem to provide valuable information regarding the periodontal disease diagnosis and prognosis. There is also an increasing evidence implicating reactive oxygen species and nitric oxide pathway in the pathogenesis of periodontal diseases. Although promising results have been achieved with the assays evaluating the markers in assessment of periodontal disease status, up to now, none of these tests are used routinely. Further, one commercially available genetic test has been reported to have the potential to be used to predict the periodontal disease, but there are controversial reports on this genetic susceptibility test.

Effect of smoking on gingival crevicular fluid cytokine profile during experimental gingivitis

BACKGROUND

Cigarette smoking is a significant risk factor in the pathogenesis of periodontal disease, able to influence both the subgingival microbiota and host responses.

AIM

The aim of the present study was to determine the influence of smoking on the amount of IL-1beta, IL-4 and IL-8 in gingival crevicular fluid (GCF) during experimental gingivitis in humans.

MATERIAL AND METHODS

Twenty-two healthy subjects, 10 smokers and 12 non-smokers, participated in the study. After professional cleaning, they performed optimal hygiene to reach perfect clinical gingival health. Oral hygiene measures were ceased for a period of 10 days. Clinical indices, including plaque index (PI), gingival index (GI), probing pocket depth (PPD) and bleeding on probing (BOP), were assessed 2 days before (day -2), at the beginning (day 0) and at the end of the experimental gingivitis period (day 10). At the same time, GCF was collected from 12 sites in each patient, by means of durapore filter membranes. Total amounts of IL-1beta, IL-4 and IL-8 were determined by enzyme-linked immunoadsorbent assay.

RESULTS

Clinical data revealed that both smokers and non-smokers showed an increase in PI, GI and BOP scores during the experiment. Although no differences were noted with regard to PI at day 10, the GI and BOP were significantly less pronounced in smokers than non-smokers (p < 0.005). Non-smokers showed higher total amounts of IL-4 but lower amounts of IL-8 than smokers, throughout the experiment. Total amounts of IL-1beta and IL-8 increased significantly during plaque accumulation in both groups. IL-4 remained stable for the smoker group and decreased for the non-smoker group.

CONCLUSIONS

The present results indicate that smoking interferes with cytokine production. When performing studies regarding the pathogenesis of periodontitis, the smoking status of the participants needs to be taken into consideration.

Position Paper: Diagnosis of Periodontal Diseases

At the present time, the diagnosis and classification of periodontal diseases are almost entirely based on traditional clinical assessments. Supplemental quantitative and qualitative assessments of the gingival crevicular fluid and subgingival microflora can potentially provide useful information about the patient's periodontal disease. In certain situations, these supplemental risk-assessment tests may be particularly valuable in establishing the endpoint of therapy prior to placing patients on a periodontal maintenance program. Although the clinical utility of none of these tests has been validated, their further development is warranted. A genetic test for susceptibility to periodontitis has become commercially available. How best to use this and future host-based tests in clinical practice remains to be determined. Probing depth and clinical attachment loss measurements obtained with periodontal probes are practical and valid methods for assessing periodontal status. Computer-linked, controlled-force electronic periodontal probes are commercially available and are currently in use by some practitioners. Many of the logistical problems associated with subtraction radiography are being overcome and this powerful diagnostic tool may soon come into widespread use. Future developments in this and other imaging techniques are likely to have a profound effect on our approach to the diagnosis of periodontal diseases.

Potential role of vascular endothelial growth factor, interleukin-8 and monocyte chemoattractant protein-1 in periodontal diseases

Host-mediated immunoinflammatory pathways activated by bacteria lead to destruction of the periodontal connective tissues and alveolar bone. The objective of this study was to elucidate the activation of the inflammatory processes in periodontal disease by quantitative assessment of cytokines and periodontopathogens. Gingival crevicular fluids (GCF) and subgingival plaque samples were collected from patients with chronic periodontitis and gingivitis and from periodontally healthy sites. Vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), and interleukin 8 (IL-8) in GCF were analyzed by enzyme-linked immunosorbent assay. Periodontopathogens, including Bacteroides forsythus, Campylobacter rectus, Porphyromonas gingivalis and Prevotella intermedia, were analyzed by immunofluorescence and dark-field microscopy. There was significantly more VEGF and IL-8 in chronic periodontitis and gingivitis sites than in periodontally healthy sites. There were significant positive correlations between the concentrations and total amounts of VEGF and IL-8 in chronic periodontitis and gingivitis sites, and between the levels of periodontopathogens and the total amounts of VEGF, MCP-1 and IL-8. These data indicate that inflammatory processes induced by periodontopathogens and the activation of certain cytokines (VEGF, MCP-1, IL-8) in periodontal diseases may be relevant to host-mediated destruction in chronic periodontitis.

Patterns of chemokines and chemokine receptors expression in different forms of human periodontal disease

Current knowledge states that periodontal diseases are chronic inflammatory reactions raised in response to periodontopathogens. Many cell types and mediators, including Th1 and Th2 lymphocytes, cytokines and chemokines, appear to be involved in the immunopathogenesis of periodontal diseases. Chemokines, a family of chemotactic cytokines, bind to specific receptors and selectively attract different cell subsets to the inflammatory site. They can also interact with classical cytokines and modulate the local immune response. In order to study the role of chemokines in periodontal diseases, we examined the expression of chemokines, chemokine receptors and cytokines by means of reverse transcription-polymerase chain reaction (RT-PCR) techniques. Characteristic patterns of such factors' expression were found in gingival biopsies from patients presenting with aggressive periodontitis and chronic periodontitis. The expression of the chemokines macrophage inflammatory protein-1 alpha (MIP-1alpha) and interferon-gamma inducible protein 10 (IP-10) and of their respective receptors, CCR5 and CXCR3, were more prevalent and higher in aggressive periodontitis, and associated with higher interferon-gamma (IFN-gamma) expression and lower interleukin-10 (IL-10) expression. In contrast, chronic periodontitis patients exhibited a more frequent and higher expression of monocyte chemoattractant protein-1 (MCP-1) and its receptor CCR4, and higher expression of IL-10. It is possible that chemokines, in addition to the classical cytokines, are involved in the immunopathogenesis of periodontal disease, driving the migration and the maintenance of several inflammatory cell types such as polymorphonuclear leukocytes, dendritic cells (DCs), natural killer cells, macrophages, and subsets of lymphocytes in the gingival tissues. These cells are thought to participate in the inflammatory and immune reaction that takes place in periodontal disease, killing pathogens, presenting antigens, and producing cytokines. The selective recruitment of polarized lymphocyte subsets could result in differential cytokine production at the site of response, which is supposed to determine the stable or progressive nature of the lesion. Besides, the role of chemokines as activators and chemoattracts of osteclasts may be involved in the determination of disease severity.

Effects of plaque, psychological stress and gender on crevicular Il-1beta and Il-1ra secretion

OBJECTIVES

The study aimed to analyse (a) whether the effects of psychological stress and of experimental gingivitis on interleukin-1beta (Il-1beta) described before are compensated by concomitant increases in Il-1 receptor antagonist (Il-1ra), and (b) whether there do exist any gender differences in the Il-1 responses to experimental gingivitis and to psychological stress.

MATERIALS AND METHODS

Thirteen medical students participating in a major academic exam (seven males, six females) and 14 medical students without academic stress (eight males, six females) refrained from oral hygiene in two antagonistic quadrants for 28 days (plaque) while they maintained oral hygiene in the remaining quadrants (hygiene). Weekly crevicular fluid samples of plaque and hygiene sites were assayed for Il-1beta and Il-1ra.

RESULTS

Neither stress nor experimental gingivitis exerted significant effects on Il-1ra. In controls, we observed significant gender and gender x time effects on Il-1beta; comparing stress groups, gender x time and stress x gender x time interactions became significant. Women show a reduced Il-1beta response to plaque at rest and an increased response under stress. Similar results were found with respect to bleeding on probing.

CONCLUSIONS

Gender must be controlled in studies on periodontal responses to pathogens. Stress plays a role in these responses.

Effects of Nd:YAG and CO2Laser Treatment and Ultrasonic Scaling on Periodontal Pockets of Chronic Periodontitis Patients

BACKGROUND

The aim of the present study was to compare the effectiveness of Nd:YAG and CO2 laser treatment to that of ultrasonic scaling used as monotherapies by examining clinical parameters, subgingival microflora, and interleukin-1 beta (IL-1beta) in gingival crevicular fluid (GCF).

METHODS

Eighteen patients, each of whom had 2 or more sites with probing depth measuring > 5 mm, were included this clinical trial. The 41 sites were randomly assigned treatment with either Nd:YAG laser alone (n = 14, 100 mj, 20 pps, 2.0 W, 120 seconds), CO2 laser alone (n = 13, 2.0 W, 120 seconds), or ultrasonic scaling alone (n = 14, maximum power, 120 seconds). At baseline and at 1, 4, and 12 weeks, clinical measurements (plaque index, PI; gingival index, GI; probing depth, PD; clinical attachment level, CAL; and bleeding on probing, BOP) were performed and subgingival plaque and GCF sampled. A quantitative analysis of Porphyromonas gingivalis was carried out using real-time polymerase chain reaction (PCR) procedures. The amounts of IL-1beta were estimated by an enzyme-linked immunosorbent assay (ELISA).

RESULTS

Decreased inflammation and PD were observed in all 3 groups after treatment. A microbiological analysis indicated significant decreases in P. gingivalis in the Nd:YAG and scaling groups at 1, 4, and 12 weeks compared to baseline (P < 0.05). The amount of GCF significantly decreased in the Nd:YAG and scaling groups at 12 weeks. The amount of IL-1beta increased in the CO2 group from baseline to 1 week (P < 0.05). The Nd:YAG group tended to show a decrease in IL-1beta from 1 to 12 weeks, although these data were not statistically significant.

CONCLUSIONS

Our data suggest that Nd:YAG laser and ultrasonic scaling treatments showed significant improvements regarding the clinical parameters and subgingival microflora compared to the baseline, but no significant difference was observed between the 3 groups.

Effect of inflammation, smoking and stress on gingival crevicular fluid cytokine level

BACKGROUND

Recent studies have shown that cytokines are pivotal to the pathogenesis of periodontal diseases and may be used as markers in diagnosis.

AIM

The aim of the present study was to determine the levels of interleukin (IL)-1beta, IL-4, IL-6 and IL-8 in gingival crevicular fluid of periodontally healthy and diseased individuals and to study their association to smoking, stress and clinical periodontal parameters.

MATERIAL AND METHODS

A total of 80 patients were included in the study : 20 patients with early onset or aggressive periodontitis (EOP), 20 with chronic adult periodontitis (AP), 20 with gingivitis (G) and 20 patients with healthy periodontium (H). GCF was collected by means of Durapore strips, from four sites per patient, randomly selected in each quadrant. The contents of IL- 1beta, IL-4, IL-6 and IL-8 were measured in 320 samples by use of commercially available sandwich enzyme-linked immunoadsorbent assays.

RESULTS

In periodontally diseased subjects the total amounts of IL-1beta, IL-6 and IL-8 were significantly elevated as compared to healthy subjects, whereas IL-4 showed an inverse relationship to periodontal status and higher amounts were found in the healthy group. The amounts of all four cytokines were positively correlated with probing depths. IL-4, IL-6 and IL-8 were significantly correlated to smoking while stress was associated with IL-1beta, IL-6 and IL-8 levels.

CONCLUSIONS

The present data suggest that crevicular IL-1beta, IL-6 and IL-8 reflect the activity of periodontal destruction, whereas IL-4 shows an inverse correlation to it. The enhanced production of inflammatory cytokines in the presence of smoking and stress may have clinical consequences.

Interleukin 1 and receptor antagonist levels in gingival crevicular fluid in heavy smokers versus non-smokers

BACKGROUND/AIMS

This study aimed to investigate the concentration of the cytokine interleukin (IL)-1beta and its receptor antagonist IL-1ra in gingival crevicular fluid (GCF) in patients with adult periodontitis who were heavy smokers compared with non-smokers.

METHOD

GCF samples were collected from two groups of subjects: smokers and non-smokers. Thirty-nine GCF samples were harvested from 13 subjects with moderate to severe adult periodontitis who were heavy smokers. A further 30 GCF samples were harvested from 10 subjects with moderate to severe adult periodontitis who were non-smokers. Subjects were selected from both genders and none had any relevant systemic illness, were pregnant, had recent medication or had received any periodontal therapy in the preceding 3 months. One deep bleeding site, one deep non-bleeding site and one healthy site were investigated in each subject. Clinical measurements were recorded for each site, after obtaining a GCF sample using a Periopaper strip. IL-1beta and IL-1ra were quantified using new commercially available ELISA kits (Quantikine), and could be detected in all samples.

RESULTS

For smokers, the mean concentrations for IL-1beta were 2714.5 (SD 4416.2) pg/ micro L for healthy sites, 37.0 (SD 57.2) pg/ micro L for non-bleeding periodontitis sites and 24.5 (SD 29.2) pg/ micro L for bleeding periodontitis sites. The concentrations of IL-1beta for non-smokers for the same category of sites were 393.8 (SD 867.1), 74.2 (SD 107.0) and 73.1 (SD 61.0) pg/ micro L, respectively. The mean concentrations of IL-1ra for smokers were 5.8 x 10(5) (SD 9.7) pg/ micro L for healthy sites, 2.2 x 10(5) (SD 0.15) pg/ micro L for deep non-bleeding sites and 0.19 x 10(5) (SD 0.07) pg/ micro L for deep bleeding sites. The concentrations for non-smokers were: 4.1 x 10(10) (SD 3.8), 18.1 x 10(5) (SD 20.4) and 3.2 x 10(5) (SD 2.3) pg/ micro L, respectively. Significance levels of P < 0.05 were found for comparisons of healthy vs. deep bleeding and deep non-bleeding sites for IL-1beta and IL-1ra in smokers, before adjustments for multiple testing. However, none of these comparisons reached statistical significance following adjustments for multiple testing. P < 0.05 for the correlation between IL-1beta and IL-1ra at healthy sites in smokers only. Differences in GCF concentrations for IL-1beta in smokers vs. non-smokers were significant for deep bleeding sites only (P < 0.05), the mean concentration of IL-1beta being lower in GCF from smokers vs. non-smokers. All differences in GCF concentrations of IL-1ra reached statistical significance for smokers vs. non-smokers. The mean concentrations of IL-1ra in GCF were lower in smokers compared with non-smokers for all categories of sites.

CONCLUSIONS

A decreased concentration of IL-1beta and also IL-1ra was found in GCF from periodontitis sites compared to healthy sites in smokers and in non-smokers, although this did not reach statistical significance following adjustments for multiple testing. For comparisons between heavy smokers and non-smokers, statistically significant differences were found in the GCF concentrations of IL-1beta from deep bleeding sites only. Statistically significant differences were found in the IL-1ra concentrations for smokers vs. non-smokers for all categories of sites.

Specific fibronectin fragments as markers of periodontal disease status

BACKGROUND

The diagnosis of progressing periodontal disease typically relies on retrospective methods that detect changes in the amount of periodontal breakdown. Fibronectin (FN) fragments are found in vivo in association with periodontal disease, and specific FN fragments compromise periodontal ligament cell functions in vitro. The overall goal of this cross-sectional study was to determine whether specific FN fragments are present in gingival crevicular fluid (GCF) and can be used as markers for periodontal disease status. The eventual goal is to test these FN fragments in a longitudinal study as potential markers of disease activity.

METHODS

GCF was collected from 94 subjects with untreated periodontitis from clinically healthy, mild/moderate periodontitis, and severe periodontitis sites. Sites were defined on the basis of clinical criteria, including gingival bleeding index, probing depth, and clinical attachment level. Western immunoblotting was used to detect FN fragments in GCF using antibodies to specific FN domains, including the collagen/gelatin-, central cell-, and carboxyl terminal heparin-binding domains, plus the CS-1 site on the alternatively spliced V region and the EIIIA region. FN fragments identified by immunoblotting and analyzed by NIH image software were scored based on pixel intensity and an ordinal grade scale.

RESULTS

We identified several fragments highly associated with severe periodontitis sites, including 40-kDa, 120-kDa, and 68-kDa fragments.

CONCLUSIONS

This study demonstrates that specific FN fragments are markers for periodontal disease status and supports the role of FN fragments as potential components in the pathogenesis of periodontal disease.

Hepatocyte growth factor in gingival crevicular fluid and the distribution of hepatocyte growth factor-activator in gingival tissue from adult periodontitis

Hepatocyte growth factor (HGF), also known as scatter factor, is a broad-spectrum and multifunctional cytokine required for the development, growth and regeneration of various organs and tissues. The expression of HGF in human gingival fibroblasts is induced by inflammatory cytokines such as interleukin 1. Thus, although it is possible that content of HGF in gingival crevicular fluid (GCF) in periodontitis is increased, this has not so far been reported because the volume of GCF is too small to determine HGF by the available enzyme-linked immunosorbent assay (ELISA). A recently developed, highly sensitive ELISA for HGF, with a detection limit of 1 pg/ml sample, has now enabled HGF to be measured in GCF.The mean HGF content in GCF from sites with clinically healthy gingiva, defined by the absence of overt signs of gingival inflammation and a probing depth (PD) <3 mm, was 1.7 ng/ml, and that of periodontitis, defined by obvious alveolar bone loss detected by radiographic examination and a PD> or =3 mm, was 3.23 ng/ml. Although treating the periodontitis did not significantly decrease the HGF concentration despite significantly improved clinical scores such as PD and Gingival Index, the total amount of HGF in GCF did decrease significantly after treatment. HGF was expressed by gingival fibroblasts and inflammatory cells as determined by in situ hybridization. HGF-activator (HGFA), which converts inactive pro-HGF to active mature HGF, was detected in gingival epithelial cells by immunostaining. The expression of HGFA was also confirmed in gingival tissue by reverse transcription-polymerase chain reaction (RT-PCR). These findings indicate that HGF is synthesized and activated in gingiva that is clinically healthy or associated with periodontitis.

Microbiological findings and host response in patients with peri-implantitis

The aim of the present study was to characterise microbiota and inflammatory host response around implants and teeth in patients with peri-implantitis. We included 17 partly edentulous patients with a total of 98 implants, of which 45 showed marginal bone loss of more than three fixture threads after the first year of loading. Nineteen subjects with stable marginal tissue conditions served as controls. Oral hygiene, gingival inflammation, and probing pocket depth were evaluated clinically at teeth and implants. Microbiological and crevicular fluid samples were collected from five categories of sites: 1) implants with peri-implantitis (PI), 2) stable implants (SI) in patients with both stable and peri-implantitis implants, 3) control implants (CI) in patients with stable implants alone, 4) teeth in patients (TP) and 5) controls (TC). Crevicular fluid from teeth and implants was analysed for elastase activity, lactoferrin and IL-1 beta concentrations. Elastase activity was higher at PI than at CI in controls. Lactoferrin concentration was higher at PI than at SI in patients with peri-implantitis. Higher levels of both lactoferrin and elastase activity were found at PI than at teeth in patients. The concentrations of IL-1 beta were about the same in the various sites. Microbiological DNA-probe analysis revealed a putative periodontal microflora at teeth and implants in patients and controls. Patients with peri-implantitis harboured high levels of periodontal pathogens, Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Bacteroides forsythus and Treponema denticola. These findings indicate a site-specific inflammation rather than a patient-associated specific host response.

Relationship of changes in interleukin-8 levels and granulocyte elastase activity in gingival crevicular fluid to subgingival periodontopathogens following non-surgical periodontal therapy in subjects with chronic periodontitis

OBJECTIVES

To determine the effect of scaling and root planing (SRP) on the interrelations of subgingival periodontopathogens and both interleukin-8 (IL-8) and granulocyte elastase activity in gingival crevicular fluid (GCF), and to assess their relations to the short-term treatment response in management of chronic periodontitis.

MATERIAL AND METHODS

GCF and subgingival plaque were collected from 16 subjects with untreated chronic periodontitis at baseline and 4 weeks after SRP. IL-8 levels were determined by ELISA. Granulocyte elastase activity was analyzed with a specific substrate, pGluProVal-pNA, and the maximal rate of elastase activity (MR-EA) was calculated. 5 DNA-probes were used to detect the presence of A. actinomycetemcomitans (A. a.), B. forsythus (B.f.), P. gingivalis (P.g.), P. intermedia (P.i.), and T. denticola (T.d.), with a sensitivity = 103 cells/paper point.

RESULTS

IL-8 and MR-EA levels in GCF decreased significantly after SRP (p < 0.001) with a corresponding reduction of total count of the species. Of the sites with probing depth (PD) >/= 5.0 mm and co-infection by B.f., P.g., P.i. & T.d. at baseline, the sites without persistent co-infection of these species after SRP exhibited a significant reduction of IL-8 levels (p < 0.02), MR-EA levels (p < 0.02) and PD (p < 0.01). No such change was found in the sites where such a co-infection persisted. Moreover, reduction of IL-8 levels in those pocket sites was accompanied by a concomitant reduction of MR-EA (p < 0.02) and PD (p < 0.01), while no significant change in MR-EA levels and PD was noted in those pocket sites that exhibited an increase of IL-8 levels after SRP. At baseline, the former group of sites showed significantly higher IL-8 levels than the latter group of sites (p < 0.02).

CONCLUSIONS

IL-8-related granulocyte elastase activity was related to the change in infection patterns of the target periodontopathogens following scaling and root planing. Varying initial IL-8 levels in GCF and a corresponding shifting change of granulocyte elastase activity in GCF may characterize the different short-term treatment responses.

IL-8 and TNF-alpha from peripheral neutrophils and acute-phase proteins in periodontitis

OBJECTIVE

In other studies, we have found deviant functions in peripheral neutrophils in periodontitis. The aim here was to study (1) the release of cytokines, IL-8 and TNFalpha, from neutrophils in 15 treated periodontitis patients and pair-matched controls as well as (2) the effects of cigarette smoking.

MATERIAL AND METHODS

Cytokines released in the incubation medium from un-stimulated and Fcgamma-R-stimulated neutrophils and some acute-phase reactants were measured with ELISA.

RESULTS

Non-smoking patients had trends for lower TNFalpha release compared to non-smoking controls, while corresponding trends were rather similar for Il-8. Smoking had a moderate but inconsistent effect on the release of both cytokines. However, in patients, the ratio between stimulated/un-stimulated release of Il-8 was significantly lowered by smoking (p<0.03). The parameters of inflammation in plasma differed only slightly between patients and controls, indicating that periodontal disease in a quiet phase has a negligible systemic effect with the possible exception for a higher IL-8 level. In contrast, smoking had significant systemic effect on the neutrophil count and IgG levels.

CONCLUSIONS

Release of IL-8 and TNF-alpha from peripheral neutrophils and various parameters of inflammation in plasma seem to be affected more by cigarette smoking than periodontal disease.

Infection-mediated early-onset periodontal disease in P/E-selectin-deficient mice

BACKGROUND

Retrospective and correlation studies suggest that early-onset periodontal disease may be due to a deficiency in phagocyte function, a pathogenic oral biofilm, and/or dysregulated gingival cytokine expression. Increased susceptibility to periodontal disease is therefore thought to result from multiple risk factors.

METHODS

We tested this hypothesis prospectively using P/E-selectin adhesion molecule deficient mice that mimic the human syndrome leukocyte adhesion deficiency II.

RESULTS

Our studies demonstrate that, in comparison to wild type animals, P/E-/- mice exhibit: spontaneous, early onset alveolar bone loss which is significant by 6 weeks of age; a 10-fold elevation in bacterial colonization of their oral cavities; and elevated gingival tissue levels of the bone resorptive cytokine IL-1alpha. Alveolar bone loss is completely prevented by prophylactic antibiotic therapy.

CONCLUSIONS

These experiments provide the first prospective evidence for the multiple risk factor hypothesis of periodontal disease, and validate the first animal model for early onset periodontitis in which both the microbiota and host response can be systematically manipulated. P/E-/- animals should be useful in testing the virulence of putative periodontal pathogens, in determining the role of host resistance factors in periodontitis, in exploring the proposed relationship(s) between infection mediated alveolar bone loss and systemic health disorders, and exploring their genetic relationships.

Gingival crevicular fluid matrix metalloproteinase-8 levels following adjunctive use of meloxicam and initial phase of periodontal therapy

BACKGROUND

The purpose of the present study was to assess the effects of adjunctive meloxicam on the matrix metalloproteinase-8 (MMP-8) levels of gingival crevicular fluid (GCF) in chronic periodontitis patients following the initial phase of periodontal therapy.

METHODS

Twelve chronic periodontitis patients received 7.5 mg meloxicam, and 10 patients received placebo tablets together with scaling and root planing in a 1 x 1 regimen for 10 days. Scaling and root planing were performed on day 3 of drug intake. The MMP-8 levels in GCF samples obtained before and on day 10 of drug intake were determined by using the immunofluorescence assay. Plaque index (PI), papilla bleeding index (PBI), and GCF MMP-8 levels were compared within each patient group, between the 2 patient groups, and also with a clinically healthy control group using non-parametric statistical analyses.

RESULTS

Both meloxicam and placebo groups showed statistically significant reductions in PBI, PI, and GCF MMP-8 levels on day 10 compared to baseline (P<0.01). The GCF MMP-8 level on day 10 in the meloxicam group was similar to the clinically healthy control group (P>0.05), while it was significantly higher in the placebo group (P<0.01). Positive correlations were found between MMP-8 total amounts and PBI scores at baseline and day 10 of drug intake in the patient groups.

CONCLUSIONS

Meloxicam showed a tendency to reduce GCF MMP-8 levels in vivo within the first 10 days when used as an adjunct in the initial phase of periodontal treatment that consists of scaling and root planing. Verification of this effect on collagenase-2 downregulation, as well as on the clinical periodontal parameters in long-term studies using larger test and control groups, is needed to provide further support for the adjunctive use of selective cyclooxygenase (COX)-2 inhibitors in the treatment of chronic periodontitis.

Production of interleukin-8 and nitric oxide in human periapical lesions

Bacterial infection of the pulp and root canal system leads to the recruitment of immunocompetent cells in the periapex and stimulates inflammatory cell responses to produce a variety of inflammatory mediators. Cytokines, reactive oxygen intermediates, and reactive nitrogen intermediates are frequently found at sites of acute inflammation. In this study, we measured the levels of interleukin (IL)-8 and nitric oxide (NO) in the periapical exudate (PE) from human periapical lesions and investigated the association of these mediators with the clinical symptoms of periapical periodontitis. PE samples were collected from root canals during routine endodontic treatments. The IL-8 concentration was measured by the enzyme-linked immunosorbent assay, and the NO level was measured as nitrite/nitrate concentration assayed by the Griess reaction. Detectable levels of IL-8 and nitrite/nitrate were found in 24 and 19 of 27 PE-samples, respectively. Although PE-IL-8 and nitrite/nitrate concentration showed a broad range, a significantly positive correlation was found between both mediators. Also, significantly higher IL-8 levels were found in PE from lesions that had painful symptoms at the sampling visit. However, there was no relationship between elevated NO levels and clinical symptoms. These results suggest that the up-regulation of IL-8 may have a critical role in the development of the symptoms of periapical disease.

The role of inflammatory and immunological mediators in periodontitis and cardiovascular disease

Epidemiological studies have implicated periodontitis (PD) as a risk factor for development of cardiovascular disease (CVD). Persistent infections such as periodontitis induce inflammatory and immune responses which may contribute to coronary atherogenesis, and, in conjunction with other risk factors, may lead to coronary heart disease (CHD). In this review, mechanisms are described that may help explain the association between periodontal infections and CHD. Periodontal diseases are bacterial infections associated with bacteremia, inflammation, and a strong immune response, all of which may represent significant risk factors for the development of atherogenesis, CHD, and myocardial infarction (MI). Several mechanisms may participate in this association, including those induced by oral organisms, and those associated with host response factors. This review will focus on host factors. Oral pathogens and inflammatory mediators (such as interleukin [IL]-1 and tumor necrosis factor [TNF]-alpha) from periodontal lesions intermittently reach the bloodstream inducing systemic inflammatory reactants such as acute-phase proteins, and immune effectors including systemic antibodies to periodontal bacteria. This review will describe the potential role of various inflammatory as well as immunologic factors that may play a role in periodontitis as a possible risk factor for CHD.

Concentration of interleukin-1beta and neutrophil elastase activity in gingival crevicular fluid during experimental gingivitis

BACKGROUND/AIM

The aim of the present study was to measure interleukin-1beta concentrations and neutrophil elastase activity in gingival crevicular fluid (GCF) during experimental gingivitis in humans.

MATERIAL AND METHODS

12 healthy young men participated. After prophylaxis, they performed optimal hygiene to reach plaque and gingivitis indices of or approaching zero. All oral hygiene measures were then ceased for a period of 18 days. The Quigley-Hein plaque index (PLI) and Saxer & Mühlemann papillary bleeding index (PBI) were assessed. GCF samples were taken from the mesiobuccal site of two contralateral teeth in the upper jaw by means of periopapers at baseline and on days 3, 7, 14 and 18. After measuring the gingival crevicular fluid volume (GCFV) with the Periotron 8000, the samples were analyzed in our laboratory for the detection of IL-1beta concentration by ELISA.

RESULTS

PLI and PBI showed a reduction prior to baseline reaching almost zero, both increasing from day 0 to day 18 (PLI=from 0.1 to 2.9, PBI=from 0 to 2.0). IL-1beta concentration increased from 229.25 ng/ml (day 0) to 526.13 ng/ml (day 18). Clinical data and IL-1beta concentrations were correlated with elastase activity (EA). No significant correlation could be demonstrated between the clinical parameters assessed and IL-1beta or EA (Spearman rank correlation coefficient). A correlation between GCFV and PBI from day 0 to day 18 could be demonstrated.

CONCLUSION

Overall, both IL-1beta and EA showed an increase from baseline throughout the whole study.

Immunodominant antigens in periodontal disease: a real or illusive concept?

The humoral arm of the immune system provides protection from many medically significant pathogens. The antigenic epitopes of the pathogens which induce these responses, and the subsequent characteristics of the host response, have been extensively documented in the medical literature, and in many cases have resulted in the development and implementation of effective vaccines or diagnostic tests. There is a substantial body of literature on the humoral immune response in periodontal disease, which is targeted at micro-organisms present within periodontal pockets. However, the significance and specificity of the immune response in periodontal disease have proved difficult to elucidate, due to the large number of potential pathogens in the plaque biofilm and the apparent commensal nature of many of these opportunistic pathogens. This review addresses our current knowledge of the approaches and strategies which have been used to elucidate and examine the concept of immunodominant antigens in medical infections and, more recently, periodontal disease. An identification/understanding of the immunodominant antigens would be informative with respect to: (i) the relative importance of the implicated pathogens, (ii) new approaches to immunological diagnosis, (iii) specific bacterial virulence determinants, (iv) natural protective responses, and (v) the selection of potential vaccine candidate antigens. We conclude that immunodominance of antigens in periodontal disease may be relevant to our understanding of periodontal disease pathogenesis, but due to the complexity and diversity of the 'pathogenic microbial ecology', it is currently an enigmatic topic requiring a multidisciplinary approach linking clinical, microbiological, and immunological investigations. We also conclude, after assessing the literature available on the topic of immunodominance, that it is a term that, if used, must be clearly defined and understood, since it is often used loosely, leading to a general misinterpretation by readers of oral and medical literature.

Levels of platelet-activating factor in gingival crevicular fluid and gingival tissue in specific periodontal diseases

BACKGROUND

Platelet-activating factor (PAF), a potent phospholipid mediator of inflammatory and immune reactions, is involved in a variety of biological responses seen in periodontal diseases. The aim of the present study was to examine the role of PAF in the pathogenesis of specific periodontal diseases.

METHODS

PAF levels were investigated in gingival crevicular fluid (GCF) and gingival tissue (GT) samples of 12 patients with generalized aggressive periodontitis (GAgP), 6 patients with localized aggressive periodontitis (LAgP), 10 patients with chronic periodontitis (CP), 6 with gingivitis (G), and 6 periodontally healthy subjects (H). Periodontal status was evaluated by measuring probing depth, gingival index, papillary bleeding index, and plaque index. PAF was extracted from GCF samples passing through amberlit resin columns, purified by high performance liquid chromatographic method, and then analyzed by radioimmunoassay.

RESULTS

GAgP, LAgP, and CP groups had significantly higher GCF PAF levels compared to the H group (P<0.005). Although statistically not significant, GCF PAF levels were also higher in the G group than those of the H group (P = 0.0784). GAgP, LAgP, and CP groups had similar GCF PAF levels (P>0.005). These groups had higher levels of GCF PAF than those of the G group, but the difference was significant only for the GAgP group (P<0.005). When the data were expressed as concentration, GAgP, LAgP, and CP groups were found to have higher concentrations of GCF PAF compared to the H group (P<0.005). GCF PAF concentration was similar in patient groups (P>0.005). All patient groups had significantly higher GT PAF levels compared to the H group (P<0.005). GAgP, LAgP, and CP groups had similar amounts of GCF and GT PAF (P>0.005). GAgP, LAgP, and CP groups had higher GT PAF levels than those of the G group, but the differences were only significant for LAgP and CP groups (P<0.005). No significant correlation was found between GCF and GT PAF levels and clinical parameters.

CONCLUSIONS

The results of the present study indicate that PAF is likely to be an important mediator in regulating inflammatory responses in the human periodontal tissues. To our knowledge, this is the first report investigating PAF levels in GCF and GT in specific periodontal diseases. We believe that this potent phospholipid mediator may need to be considered in the pathogenesis of periodontal diseases.

Effect of non-surgical periodontal therapy on C-telopeptide pyridinoline cross-links (ICTP) and interleukin-1 levels

BACKGROUND

Biochemical markers harvested from gingival crevicular fluid (GCF) may be useful to identify and predict periodontal disease progression and to monitor the response to treatment. C-telopeptide pyridinoline cross-links (ICTP), a host-derived breakdown product specific for bone, and interleukin-1beta (IL-1), a potent bone-resorptive cytokine, have been associated with periodontal tissue destruction. The aim of this study was to examine the effect of non-surgical periodontal therapy on GCF levels of ICTP and IL-1.

METHODS

Twenty-five chronic periodontitis subjects were monitored at 8 sites per subject at baseline prior to scaling and root planing and 1, 3, and 6 months after therapy. Four shallow (probing depths < 4 mm) and 4 deep (probing depths > or = 5 mm) sites were monitored for both marker levels and clinical parameters. GCF was collected for 30 seconds on paper strips, and levels of ICTP and IL-1 were determined using radioimmunoassay (RIA) and enzyme-linked immunosorbent assay (ELISA) techniques, respectively. Clinical measurements included probing depth (PD), clinical attachment level (CAL), and bleeding on probing (BOP).

RESULTS

Deep sites exhibited significantly (P<0.001) higher ICTP and IL-1 levels compared to shallow sites at all time intervals. ICTP demonstrated a stronger association to clinical parameters than IL-1 including a modest correlation (r = 0.40, P<0.001) between ICTP and attachment loss. Significant improvements in PD, CAL, and BOP were observed at 1, 3, and 6 months in all sites (P<0.01). However, non-surgical mechanical therapy did not significantly reduce ICTP and IL-1 levels over the 6-month period. Further examination of subjects based on smoking status revealed that ICTP levels were significantly reduced at 3 and 6 months and IL-1 levels reduced at 3 months among non-smokers only.

CONCLUSIONS

A single episode of non-surgical mechanical therapy did not significantly reduce biochemical markers associated with bone resorption in patients exhibiting chronic periodontitis. Future longitudinal studies are warranted to specifically evaluate the relationship between C-telopeptide pyridinoline cross-links and periodontal disease progression.

Levels of leukotriene B4 in gingival crevicular fluid and gingival tissue in specific periodontal diseases

BACKGROUND

Leukotriene B4 (LTB4), a product of the lipoxygenase pathway of arachidonic acid metabolism, exhibits numerous activities that can account for most of the features of host responses seen in periodontal diseases. The aim of the present study was to examine the role of LTB4 in the pathogenesis of specific periodontal diseases.

METHODS

LTB4 levels were investigated in gingival crevicular fluid (GCF) and gingival tissue (GT) samples of 10 patients with chronic periodontitis (CP), 12 patients with generalized aggressive periodontitis (GAgP), 6 patients with localized aggressive periodontitis (LAgP), 6 patients with gingivitis (G), and 6 periodontally healthy subjects (H). Periodontal status was evaluated by measuring probing depth, gingival index, papillary bleeding index, and plaque index. LTB4 was extracted from the samples by solid-phase method using C18 cartridge and was purified by high performance liquid chromatographic method and then analyzed by radioimmunoassay.

RESULTS

All patient groups had significantly higher levels of GCF and GT LTB4 compared to the control group (P<0.005). The CP patients had the highest LTB4 levels compared to those in other patient groups (P<0.005). GAgP, LAgP, and G groups had similar amounts of GCF and GT LTB4 (P>0.005). When the data were expressed as concentration, the CP group was found to have higher concentration of LTB4, compared to that of control group (P<0.005). GAgP, LAgP, and G groups had similar LTB4 concentration compared to that of control group (P>0.005). No significant difference was found between GAgP, LAgP, and G groups (P>0.005). The CP group had higher LTB4 concentration compared to both GAgP and LAgP groups (P<0.005). Although the CP group had a higher GCF LTB4 concentration compared to G group, this difference did not reach significance (P>0.005). No significant correlation was found between GCF and GT LTB4 levels and clinical parameters.

CONCLUSIONS

The results of the present study indicate that LTB4 is likely to be an important mediator in regulating inflammatory responses in the human periodontal tissues. This lipid mediator may play an important role in the pathophysiology of periodontal disease.

Interleukin-1beta and thiobarbituric acid reactive substance (TBARS) levels after phase I periodontal therapy in patients with chronic periodontitis

BACKGROUND

Interleukin-1beta (IL-1beta), a potent stimulator of bone resorption, has been implicated in the pathogenesis of periodontal tissue destruction. There is also a clearly defined and substantial role for free radicals or reactive oxygen species in periodontal destruction. The thiobarbituric acid reactive substances (TBARS) is a commonly applied test to measure free radical activity. The aims of this study were to investigate the amount of crevicular IL-1beta, tissue TBARS levels, and the clinical status of patients with advanced chronic periodontitis and the effect of phase I periodontal therapy on these clinical parameters and measurements.

METHODS

Twenty-five chronic periodontitis and 25 healthy control (C) patients were selected for the study. Plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment level (CAL) were recorded from each sampling area. Gingival crevicular fluid (GCF) sampling and clinical index scores were recorded at the initial examination (IE) and 6 weeks after phase I periodontal therapy (APT). Assays for GCF IL-1beta were carried out by enzyme-linked immunosorbent assay (ELISA). Gingival tissue samples were obtained from sites requiring periodontal flap surgery due to unresolved pockets to determine the tissue TBARS levels. The paired-samples t test was used to compare the IL-1beta levels and clinical parameters between IE and APT. The independent-samples t test was used to determine the significance of all parameters between IE and C, and between APT and C. The correlation among the IL-1beta levels, clinical parameters, and tissue TBARS levels was analyzed using the Pearson correlation.

RESULTS

The concentration of IL-1beta levels was not statistically different among IE, APT, and C groups, but the total amount of IL-1beta levels was statistically different among the 3 groups. While the levels of IL-1beta and the clinical parameters were reduced following phase I periodontal treatment, pretreatment IL-1beta, post-treatment IL-1beta, and TBARS levels were statistically higher in IE and APT groups than C specimens. Tissue TBARS levels in the APT group were statistically greater than controls. No correlations were noted between tissue TBARS levels and clinical parameters in the APT group. A positive statistical correlation was detected between the total IL-1beta and TBARS levels in the APT group.

CONCLUSION

These data suggest that the levels of crevicular IL-1beta and gingival tissue TBARS are closely associated with periodontal status. This relationship may be valuable in treating and monitoring periodontal disease progression.

Production of inflammatory cytokines by human gingival fibroblasts stimulated by cell-surface preparations of Porphyromonas gingivalis

Porphyromonas gingivalis is a gram-negative rod associated with the progression of human periodontal disease. Inflammatory cytokines are believed to be the major pathological mediators in periodontal diseases. We therefore investigated the productions of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-alpha) in human gingival fibroblasts treated with lipopolysaccharide, polysaccharide and outer-membrane proteins from P. gingivalis ATCC 53977. Outer-membrane protein from P. gingivalis enhanced the production of IL-6 and IL-8 from the cells of periodontium in vitro as well as lipopolysaccharide did. The IL-8 production activity of polysaccharide from P. gingivalis was higher than that of other cell-surface components. The levels of IL-6 and IL-8 released from the P. gingivalis lipopolysaccharide-treated human gingival fibroblasts were lower than those of the same cells treated with lipopolysaccharides from Actinobacillus actinomycetemcomitans or Escherichia coli. Rabbit antisera against either outer-membrane protein or lipopolysaccharide inhibited the IL-6 and IL-8 production derived from human gingival fibroblasts stimulated sonicated supernatants from P. gingivalis. The present study suggests that, in addition to lipopolysaccharide, outer-membrane protein and polysaccharide of P. gingivalis are also pathological mediators in periodontal diseases.

Evaluation of transforming growth factor-beta 1 level in crevicular fluid of cyclosporin A-treated patients

BACKGROUND

The aim of the present study was to investigate the level of transforming growth factor-beta 1 (TGF-beta 1) in gingival crevicular fluid (GCF) samples of cyclosporin A (CsA)-treated patients and to compare the results with control groups.

METHODS

Fourteen renal transplant patients exhibiting severe CsA-induced gingival overgrowth, 10 patients with chronic gingivitis, and 10 subjects with clinically healthy periodontium were included in the study. In CsA-treated patients, GCF samples were harvested from sites exhibiting gingival overgrowth (CsA GO+) and sites not exhibiting gingival overgrowth (CsA GO-). The TGF-beta 1 levels in a total of 96 GCF samples from the 34 participants were analyzed by enzyme-linked immunosorbent assay. The results were expressed in terms of total amount (pg/2 sites) and concentration (ng/ml).

RESULTS

TGF-beta 1 total amounts in CsA GO+ and CsA GO- sites were similar and significantly higher than that of healthy sites (P < 0.02 and P < 0.01, respectively). The total amount of TGF-beta 1 was also higher in gingivitis sites compared to the healthy sites, but the difference was not statistically significant (P > 0.05). CsA GO+ and CsA GO- sites exhibited higher total amount and concentration of TGF-beta 1 than that of gingivitis sites, but the differences were insignificant (P > 0.05).

CONCLUSIONS

The results of the present study support the theory that CsA increases the synthesis of TGF-beta 1 in GCF. However, since the difference between CsA GO+ and CsA GO- sites was not statistically significant, it seems unlikely that GCF TGF-beta 1 level is the sole factor responsible for the CsA-induced gingival overgrowth. Complex interactions between various mediators of inflammation and tissue modeling are possibly involved in the pathogenic mechanisms of this side effect.

Levels of interleukin-1 beta, -8, and -10 and RANTES in gingival crevicular fluid and cell populations in adult periodontitis patients and the effect of periodontal treatment

BACKGROUND

Various cytokines have been identified at sites of chronic inflammation such as periodontitis. Cytokines are synthesized in response to bacteria and their products, inducing and maintaining an inflammatory response in the periodontium. The purpose of the present study was to investigate the involvement of interleukin-1 beta (IL-1 beta), IL-8, and IL-10 and RANTES (regulated on activation, normally T cell expressed and secreted) and the cell populations associated with the immune response in destructive periodontitis, as well as the effect of periodontal therapy on cytokine levels in gingival crevicular fluid (GCF).

METHODS

Data were obtained from 12 patients with moderate to advanced periodontitis and 6 healthy controls. Patients presenting at least 2 sites with > or =2 mm clinical attachment loss were included in the destructive periodontitis group. After monitoring for 4 months, only 6 patients showed destructive periodontitis and GCF samples and soft tissues biopsies were collected from these patients. GCF samples and biopsies were collected both from active (12 CGF samples and 6 biopsies) and inactive (12 CGF samples and 6 biopsies) sites. The comparison with healthy controls was carried out by collecting GCF samples from 6 healthy volunteers (12 samples) and biopsies during the surgical removal of wisdom teeth. In periodontal patients, clinical data and GCF samples were obtained prior to periodontal treatment (72 samples) and 2 months after periodontal therapy (72 samples). GCF was collected using a paper strip; eluted and enzyme-linked immunoabsorbent assays (ELISA) were performed to determine cytokine levels. The inflammatory infiltrate was analyzed by immunohistochemistry of gingival biopsy samples with monoclonal antibodies against CD3, CD8, CD4, CD11c, and CD19 antigens.

RESULTS

Cellular components of the inflammatory infiltrate include B and T lymphocytes and monocyte/macrophages. Active sites contained a higher number of B lymphocytes and macrophages. IL-8 and IL-1 beta and RANTES in GCF were detected in the majority of sites from periodontal patients (100%, 94% and 87%, respectively); IL-10 was found in only 43%. IL-8 was the only cytokine detected in the GCF (75%) of the control group. Moreover, IL-1 beta levels were significantly higher in active sites versus inactive sites (P <0.05). IL-8 and IL-10 and RANTES were increased in active sites; however, differences were not significant (P>0.05). A positive correlation between the IL-8 and RANTES (r = 0.677, P<0.05) was observed in periodontitis patients. Periodontal therapy reduced the total amount of IL-1 beta, IL-8, and IL-10 and RANTES. Data showed a weak correlation between the clinical parameters and the total amount of cytokines in periodontitis.

CONCLUSIONS

These data suggest that the amount of crevicular IL-1 beta, IL-8, and IL-10 and RANTES is associated with periodontal status. Removal of the bacterial plaque reduces the antigenic stimuli and consequently could modulate the chemokines present in GCF. We propose that the dynamic interactions between cytokines, their production rates, and their quantity could represent factors controlling the induction, perpetuation, and collapse of the cytokine network present in the periodontal disease.

Cytokine responses of oral epithelial cells to Porphyromonas gingivalis infection

Accumulating evidence indicates that epithelia are not merely mechanical barriers but also important elements of the innate immune system. The present study was performed to examine cytokine responses of oral epithelial cells after infection with the periodontal pathogen Porphyromonas gingivalis. The KB-cell line and primary cultures of periodontal pocket epithelium were infected with P. gingivalis for assessment of bacterial invasion by an antibiotic protection assay, and examination of expression of interleukin-1 beta, interleukin-6, interleukin-8, and tumor necrosis factor-alpha by in situ hybridization and immunohistochemistry. We observed that P. gingivalis induces a strong cytokine response, positively correlated with the adhesive/invasive potential of the infecting strain, in both KB cells and primary cultures. These findings indicate that the epithelial cells of the periodontal pocket are an integral part of the immune system, eliciting cytokine responses to a bacterial challenge. In this context, the adhesive/invasive phenotype of P. gingivalis appears to contribute to pathogenicity.

Enhanced interleukin-1beta, interleukin-6 and tumor necrosis factor-alpha production by LPS stimulated human monocytes isolated from HIV+ patients

Periodontal disease and tooth loss is a common finding among advanced HIV+ patients. In addition to local oral lipopolysaccharide (LPS) stimulation, systemic up-regulation of monocyte pro-inflammatory cytokine secretion may also be involved in the pathogenesis of HIV disease. A study was undertaken to investigate IL-1beta, IL-6 and TNF-alpha production by resting and LPS stimulated monocytes isolated from HIV+ patients and also to investigate the relationship of the patient's HIV viral load status to the cytokine production. Whole blood samples in EDTA were collected from 39 HIV-1 infected patients and 20 age and sex matched uninfected controls. Plasma was separated by centrifugation. Viral load was determined using a quantitative RT-PCR. Monocytes were isolated by Ficoll-hypaque gradient separation followed by overnight plastic adherence. Cultured monocytes (1x10(6)/ml) were stimulated with LPS (1 microg/ml) of either P. gingivalis or F. nucleatum for 2, 8, 24 and 48 h and supernatant fluids were collected. IL-1beta, IL-6, and TNF-alpha levels in supernatant fluids were estimated by ELISA. Increased overall production of IL-1beta, IL-6 and TNF-alpha by LPS stimulated monocytes isolated from HIV-1 infected patients was observed when compared to HIV-1 uninfected controls. LPS stimulated monocytes from HIV-1 infected patients with high viral load (HVL) produced significant (p<0.05) elevations in these pro-inflammatory cytokines when compared to HIV-1 uninfected controls. Both LPS of P. gingivalis and F. nucleatum produced a comparable cytokine production by monocytes after 8 h of stimulation. These data suggest that enhanced IL-1beta, IL-6 and TNF-alpha is produced by monocytes/macrophages isolated from HVL HIV+ patients and may be involved in the overall pathogenesis of HIV-1 infection.

Interleukin-8 and granulocyte elastase in gingival crevicular fluid in relation to periodontopathogens in untreated adult periodontitis

BACKGROUND

This study aimed to determine the relationships among interleukin (IL)-8 and granulocyte elastase levels in gingival crevicular fluid (GCF) and the concomitant presence of periodontopathogens in untreated adult periodontitis.

METHODS

GCF and subgingival plaque samples were collected from 16 patients with untreated adult periodontitis and 10 healthy control subjects. IL-8 levels were determined by enzyme-linked immunosorbent assay (ELISA). Granulocyte elastase was analyzed with a neutrophilic granulocyte-specific, low molecular weight and chromogenic substrate, L-pyroglutamyl-L-prolyl-L-valine-p-nitroanilide, and the maximal rate of elastase activity (MR-EA) was calculated. Five DNA probes were used to detect the presence of A. actinomycetemcomitans (A.a.), B. forsythus (B.f.), P. gingivalis (P.g.), P. intermedia (P.i.), and T. denticola (T.d.).

RESULTS

Lower IL-8 concentrations and higher granulocyte elastase activities were found in patients than in healthy controls as well as in diseased conditions co-infected with B.f., P.g., P.i., and T.d. as compared to healthy conditions without the target species (P <0.05). IL-8 concentrations were positively correlated with MR-EA levels in the periodontitis conditions co-infected with B.f., P.g., P.i., and T.d. (P <0.05). A wide range of IL-8 concentrations was found among 15 patients when the periodontitis condition was characterized by co-infection with B.f., P.g., P.i., and T.d. MR-EA levels in the high IL-8 group of subjects were significantly higher than those in the low IL-8 group of subjects (P <0.01).

CONCLUSIONS

The present study shows that the local host-bacteria interactions in untreated periodontitis are diverse in terms of the intensity of inflammatory responses measured by IL-8-related granulocyte elastase activity in GCF. This might reflect different phases of the inflammatory response due to shifts in host-bacteria interactions and therefore be indicative of a range of periodontal disease activity levels.

Enhanced interleukin 1 beta, interleukin 6 and tumor necrosis factor alpha in gingival crevicular fluid from periodontal pockets of patients infected with human immunodeficiency virus 1

Loss of periodontal support and eventually tooth loss is a common finding among acquired immunodeficiency syndrome (AIDS) patients. The cause of this destruction may be an increase in periodontal disease activity at sites within the same individual and also may be related to an increase in the pro-inflammatory cytokines, diffused through the gingival crevicular sulcus in AIDS patients. A study was undertaken to determine the relative levels of the pro-inflammatory cytokines, interleukin 1 beta (IL-1 beta), IL-6, and tumor necrosis factor alpha (TNF-alpha), in gingival crevicular fluid collected from the deep (> 5 mm periodontal pocket depth) and shallow (< or = 3 mm periodontal pocket depth) periodontal pockets of 39 HIV-1-infected patients and 20 age-, race- and sex-matched uninfected controls. Complete medical history including risk factors such as intravenous drug abuse was taken. Gingival crevicular fluid samples were collected on periopaper strips. Cytokines were estimated by solid-phase enzyme-linked immunosorbent assay. To assess the degree of HIV activity, the viral load of these patients was determined by an Amplicor HIV-1 monitor kit using reverse transcriptase polymerase chain reaction. Gingival crevicular fluid from HIV-1-infected patients showed a two-fold increase in both IL-1 beta and TNF-alpha in deep periodontal pockets in comparison to shallow pockets, whereas IL-6 increased 1.8-fold. There was a significant (P < 0.05) increase in IL-1 beta, IL-6 and TNF-alpha in gingival crevicular fluid (both shallow and deep pockets) from HIV-1-infected patients in comparison to uninfected controls and also significantly elevated in deep versus shallow pockets in these patients. Although IL-1 beta, L-6 and TNF-alpha levels among HIV-1-infected patients with a high viral load (> 10,000 copies/ml) were higher than those from patients with a low viral load (< 400 copies/ml), only the increase in IL-1 beta level associated with deep pockets was significant (P < 0.05). There was also a trend of an increase in all the three cytokines among intravenous drug-abusing HIV-1-infected patients in comparison to non-intravenous drug abusers, but only the difference in IL-1 beta levels from deep pockets reached significance (P < 0.05). These enhanced pro-inflammatory cytokine levels in the gingival crevicular fluid of HIV-positive patients may be an important factor in causing the advanced periodontal lesions sometimes observed in HIV-positive patients.

Suppression of interleukin-10 release from human periodontal ligament cells by interleukin-1beta in vitro

Periodontitis is characterized by an inflammatory process induced by periodontopathogenic bacteria in the subgingival plaque. Periodontal inflammation can be enhanced by both an increase of inflammatory stimulators, e.g. interleukin (IL)-6, and a decrease of inflammatory inhibitors, e.g. IL-10. The amount of IL-1beta is known to be increased in gingival tissues and in the gingival crevicular fluid from inflamed sites compared to healthy sites. This in vitro study sought to clarity whether IL-1beta (1 ng/ml) has a regulatory effect on the release of these two cytokines from human periodontal ligament (PDL) cells. PDL cells derived from healthy premolars were grown in the presence and absence (control) of IL-1beta. The concentration of IL-6 and IL-10 in the supernatants was assessed by enzyme-linked immunosorbent assay after 48 h of culture. PDL cells incubated with IL-1beta released significantly (p < 0.05) higher amounts of IL-6 and significantly (p < 0.01) smaller amounts of IL-10 compared to control. These results give further support to the observation that IL-1beta can increase the IL-6 secretion from PDL cells. Moreover, they provide original evidence that PDL cells secrete IL-10, which can be suppressed by IL-1beta. It is concluded that PDL cells can function as accessory immunoinflammatory cells amplifying the inflammatory process in periodontitis and, thereby, contributing to periodontal breakdown.

Levels of leukotriene B4 and platelet activating factor in gingival crevicular fluid in renal transplant patients receiving cyclosporine A

BACKGROUND

Cyclosporine A (CsA) is a potent immunosuppressant effectively used to prevent organ transplant rejection and also to treat several systemic diseases. CsA-induced gingival overgrowth (CsA GO) is the most widely seen side effect of this drug; its pathogenesis is not completely understood. The aim of the present study was to identify the role of leukotriene B4 (LTB4) and platelet activating factor (PAF) in the pathogenesis of CsA GO.

METHODS

LTB4 and PAF levels were detected in gingival crevicular fluid (GCF) samples from renal transplant patients receiving CsA therapy and exhibiting CsA GO, from patients with gingivitis and from periodontally healthy subjects. Plaque index, papilla bleeding index, and hyperplastic index were recorded at each study site. GCF samples and clinical data were obtained from: 2 sites exhibiting CsA GO (CsA GO+) and 2 sites not exhibiting CsA GO (CsA GO-) in each CsA-treated patient; 2 diseased sites in each patient with gingivitis; and 2 healthy sites in each subject with clinically healthy periodontium. LTB4 was extracted from the samples by solid-phase method using C18 cartridge and purified by high-performance liquid chromatographic (HPLC) method and analyzed by radioimmunoassay (RIA). PAF was extracted from GCF samples passing through amberlit resin columns, purified by HPLC, and analyzed by RIA.

RESULTS

Total amounts of LTB4 and PAF in GCF were higher in CsA GO+ sites compared to the healthy sites from healthy controls. However, the amount of LTB4 and PAF elevation in CsA GO+ sites was not significantly higher than those in diseased sites. Clinical degrees of gingival inflammation were also similar between CsA GO+ and diseased sites. LTB4 and PAF total amounts in GCF were higher in CsA GO+ sites compared to CsA GO- sites in the same subjects, but this difference just failed to reach significance. Similar findings were obtained with concentration data.

CONCLUSIONS

The results of this study indicate that CsA therapy does not have a significant effect on GCF LTB4 and PAF levels and that gingival inflammation seems to be the main reason for their elevation. In CsA-treated patients, alterations in LTB4 and PAF levels might play a role in CsA GO through some asyet unknown mechanism. To our knowledge, this is the first report describing the levels of lipid mediators in GCF of CsA-treated patients. We assume that further studies will contribute to the understanding of the pathogenesis of CsA-induced gingival overgrowth.

Increased interleukin-1beta concentration in gingival crevicular fluid as a characteristic of periodontitis

BACKGROUND

The levels of interleukin-1beta (IL-1beta) have been reported to be higher in sites with periodontitis than in healthy controls. This may be the result of a more severe inflammation and/or constitutional differences in IL-1beta production. Our aim was to test the hypothesis that the level of IL-1beta in gingival crevicular fluid (GCF) is a characteristic trait of periodontitis, regardless of the degree of tissue destruction. As a secondary aim, we investigated the correlation between IL-1beta and neutrophil elastase. An untreated population was used.

METHODS

GCF samples from inflamed sites in 13 patients with gingivitis (GG), and from inflamed sites with shallow (GP) and deep (PP) pockets in 18 patients with periodontitis were collected. Interleukin-1beta, elastase-alpha-1-antitrypsin complex (E-A1AT), alpha-1-antitrypsin (A1AT), and alpha-2-macroglobulin (A2MG) were measured with ELISA. Elastase activity was measured with a specific substrate.

RESULTS

The concentration of IL-1beta was significantly higher in PP than in GG, but no significant differences were detected between PP and GP. A weak positive correlation between the elastase activity and IL-1beta was also observed. The elastase activity had a tendency to be higher in PP, although no significant difference was found among the 3 groups. The concentrations of E-A1AT, A1AT, and A2MG were similar in the 3 types of sites.

CONCLUSIONS

The levels of IL-1beta in GCF were increased in samples from periodontitis patients, regardless of the severity of disease at the sampled site, suggesting that the levels of IL-1beta are typical of a given patient.

Role of soluble interleukin-6 receptor in inflamed gingiva for binding of interleukin-6 to gingival fibroblasts

Interleukin-6 (IL-6), frequently detected in periodontitis, is known to mediate important signals in the inflammatory cytokine network. Gingival fibroblasts (GF) secrete cytokines upon stimulation with inflammatory mediators. However, it is not clear if GF respond to IL-6. We examined the IL-6 receptor gene expression in GF. Furthermore, we tested whether GF are target cells for IL-6 by examination of binding of IL-6. GF were found to contain trace amounts of mRNA for IL-6 receptor (IL-6R), but had high levels of mRNA for 130-kDa glycoprotein (gp130), which is a signal transducer for IL-6/IL-6R complex. Based on this observation, we hypothesized that IL-6 could bind GF if exogenous soluble forms of IL-6R (sIL-6R) existed in the gingiva or culture condition. Thus, we investigated the existence of sIL-6R in gingiva using enzyme-linked immunosorbent assay and whether sIL-6R influenced the binding of IL-6 to GF in vitro. In inflamed gingiva, sIL-6R was detected and its concentration ranged from 150 to 700 pg/microgram protein. The sIL-6R enhanced the binding of IL-6 to GF in a dose-dependent manner. This enhancement was inhibited by an antibody against gp130, suggesting that the IL-6/sIL-6R complex bound to the fibroblasts via gp130. These data demonstrated that gingival fibroblasts can be target cells for IL-6 in the presence of appropriate amounts of sIL-6R. This situation may exist during inflammation in periodontal tissue.

The influence of interleukin gene polymorphism on expression of interleukin-1beta and tumor necrosis factor-alpha in periodontal tissue and gingival crevicular fluid

BACKGROUND

A specific composite genotype of the polymorphic interleukin-1 (IL-1) gene cluster has recently been associated with severe periodontitis. One polymorphism of the composite periodontitis-associated genotype (PAG) has been functionally linked with expression of high levels of IL-1. The purpose of this study was to test whether gingival crevicular fluid (GCF) levels of IL-1beta and tumor necrosis factor-alpha (TNFalpha), and gingival tissue levels of IL-1alpha, IL-1beta, and TNFalpha correlate with PAG, and to examine the effect of conservative periodontal therapy on these levels.

METHODS

Twenty-two adults with moderate to advanced periodontal disease were enrolled. Polymerase chain reaction amplification and restriction enzymes were used to identify specific polymorphisms from peripheral blood samples. GCF samples were collected at baseline and 3 weeks following conservative treatment and analyzed by ELISA for IL-1beta and TNFalpha. An interproximal gingival biopsy was collected at baseline and follow-up and analyzed for IL-1alpha, IL-1beta, and TNFalpha by ELISA.

RESULTS

The genotyping identified 7 as PAG(+) and 15 as PAG(-). The 2 groups were comparable in terms of existing periodontitis and age. In shallow sites (<4 mm), total IL-1beta in GCF was 2.5 times higher for PAG(+) patients prior to treatment (P=0.03), and 2.2 times higher after treatment (P=0.04), while differences were less apparent in deeper sites. Following treatment, a reduction in IL-1beta concentration in GCF was seen for PAG(-) but not for PAG(+) patients. While not statistically significant, a trend was observed in mean tissue levels of IL-1beta which were 3.6 times higher in PAG(+) versus PAG(-) patients (P=0.09).

CONCLUSIONS

These data suggest that PAG(+) patients may demonstrate phenotypic differences as indicated by elevated levels of IL-1beta in GCF.

The pathogenesis of periodontal diseases

This informational paper was prepared by the Research, Science, and Therapy Committee of The American Academy of Periodontology, and is intended for the information of the dental profession. The purpose of the paper is to provide an overview of current knowledge relating to the pathogenesis of periodontal diseases. The paper will review biological processes thought to provide protection against periodontal infections. It will further discuss the mechanisms thought to be responsible for both overcoming and subverting such protective mechanisms and those that lead to destruction of periodontal tissues. Since an understanding of pathogenic mechanisms of disease is one foundation upon which new diagnostic and therapeutic modalities are based, the practitioner can use this information to help make decisions regarding the appropriate application of such new modalities in patient care settings.

CD40 engagement modulates the production of matrix metalloproteinases by gingival fibroblasts

Chronic periodontitis is a destructive inflammatory disease linked with unbalanced production between matrix metalloproteinases (MMPs), such as interstitial collagenase (MMP-1) and stromelysin-1 (MMP-3) and their endogenous tissue inhibitors of MMPs (TIMPs). In addition to aberrant MMP-1 and MMP-3 expression, periodontal lesions are characterized by dense infiltrations of activated T lymphocytes which may interact with CD40-expressing gingival fibroblasts in the connective tissue via the CD40L-CD40 pathway. In this study we investigated whether CD40 cross-linking influenced MMP production by gingival fibroblasts. Therefore, we analysed the CD40L-induced MMP production by these fibroblasts in the presence of cytokines that are increased in periodontal lesions, such as IL-1beta, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). We show that CD40 ligation on gingival fibroblasts resulted in a decrease of their MMP-1 and MMP-3 production, while MMP-2 and TIMP-1 production were unaffected as determined by Western blot. This down-regulatory effect of CD40 engagement on MMP-1 and MMP-3 production by gingival fibroblasts was also present when MMP production was up-regulated by IL-1beta and TNF-alpha or down-regulated by IFN-gamma. These results suggest that CD40 ligation on gingival fibroblasts leads to a restraining of MMP-1 and MMP-3 production by gingival fibroblasts and thereby may be an important mechanism in the retardation of further periodontal tissue damage.

The correlation of gingival crevicular fluid interleukin-8 levels and periodontal status in localized juvenile periodontitis

Localized juvenile periodontitis (LJP) is an early-onset periodontal disease characterized by progressive bone loss involving the permanent first molar and incisor teeth. Approximately 70% to 75% of LJP patients have impaired neutrophil chemotaxis towards a number of chemoattractants including N-formyl-methionyl-leucyl-phenyl-alanine, complement fragment C5a, leukotriene B4, and interleukin 8 (IL-8). The aim of the present study was to observe the role of IL-8 in the pathogenesis of LJP. Fourteen individuals who were systemically and periodontally healthy and 24 systemically healthy individuals diagnosed with LJP (based on the results of clinical periodontal assessments and radiographic examination) were recruited for this study. Gingival crevicular fluid (GCF) samples were obtained from anterior teeth in each subject before treatment. After evaluation of GCF amount from paper strips, enzyme-linked immunoabsorbent assay was employed to determine the amount of IL-8 in GCF. The amount and concentration of IL-8 measured was 894.5 +/- 435 pg, and 445.3 +/- 468 pg/microl for the experimental group and 747.3 +/- 543 pg and 684.7 +/- 548 pg/microl, for the control group. The correlation among the levels of cytokine and clinical parameters was assessed. It was observed that the concentration of IL-8 demonstrated a negative correlation with gingival index in the LJP group. In addition, no significant correlation was found among the total amount and concentration of IL-8, GCF volume, and clinical parameters in the control group. IL-8 is thought to enhance host defense mechanisms against gram-negative bacteria, thus providing protection against periodontal infections. Our data demonstrate that, when both the total amount and concentration of IL-8 are taken into consideration, no significant difference between LJP and healthy subjects is shown. This may indicate a less active IL-8 production compared with healthy subjects in spite of the dense Gram bacterial stimulation in LJP.

Interleukin-1beta+3953 allele 2: association with disease status in adult periodontitis

Adult periodontitis is a complex multifactorial disease whose etiology is not well defined. The pro-inflammatory and bone resorptive properties of interleukin-1 beta (IL-1beta) strongly suggest a role for this cytokine in the pathogenesis of periodontal disease. In the study reported here, the frequency of IL-1beta genotypes including allele 2 of the IL-1beta+3953 restriction fragment length bi-allelic polymorphism was significantly increased in patients with advanced adult periodontitis compared to those with early and moderate disease. Furthermore, allele 2 was associated with increased production of IL-1beta by activated peripheral blood polymorphonuclear cells of patients with advanced disease, although this increase failed to reach statistical significance. Finally, the data obtained revealed significant linkage disequilibrium between allele 2 of the IL-1beta+3953 polymorphism and allele 2 of the bi-allelic IL-1alpha-889 polymorphism in both patients and orally healthy controls. These findings provide new insight into the possible role of IL-1alpha and beta gene polymorphisms in the susceptibility to adult periodontitis.

The relationship between concentrations of proinflammatory cytokines within gingiva and the adjacent sulcular depth

The objective of this study was to determine and compare concentrations and ratios of 3 proinflammatory cytokines, interleukin (IL) IL-1beta, IL-6, and IL-8 within gingival tissue biopsies adjacent to < or = 3, 4 to 6, or >6 mm sulci. All gingiva adjacent to > or = 4 mm sulci had clinical evidence of active inflammation. Factorial analysis of variance suggested significant effects of sulcus depth on the type and concentration of the three cytokines in the adjacent gingiva (P < 0.001). IL-8 concentrations were highest in gingiva adjacent to < or = 3 and lowest adjacent to >6 mm sulci (P < 0.001). In contrast, IL-6 concentrations were lowest in gingiva adjacent to < or = 6 mm and highest adjacent to >6 mm sites. IL-1beta concentrations were highest in gingiva adjacent to >6 mm and lowest adjacent to 4 to 6 mm sites; they were also higher adjacent to < or = 3 mm than adjacent to 4 to 6 mm sites (P < 0.01). Multiple regression analysis suggested that sulcular depth, type of cytokine, and cytokine concentration were significantly correlated (P < 0.001). Ratios of gingival cytokines changed with increased sulcular depth. In gingiva adjacent to < or = 6 mm sites, IL-8 was the most and IL-6 the least prevalent. In gingiva adjacent to > or = 6 mm sites, IL-8 was the least and IL-1-beta the most prevalent. The data suggest that the characteristics of the gingival cytokine network are affected by adjacent sulcular depth. These data could be used to design adjunct diagnostic tests for progression of periodontal diseases.

Crevicular fluid interleukin-1beta, tumor necrosis factor-alpha, and interleukin-6 levels in renal transplant patients receiving cyclosporine A

Cyclosporine A(CsA) is successfully used to prevent graft rejection in organ transplantation and in the treatment of various systemic diseases. CsA-induced gingival overgrowth (CsA GO) is one of the most important side effects of this drug. However, the pathogenesis of this side effect is still unclear. It has been postulated that CsA-induced alterations of cytokine levels in gingival tissues might play a role in the drug-induced gingival overgrowth. The purpose of the present study was to determine the levels of interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), and IL-6 in gingival crevicular fluid (GCF) samples from renal transplant patients receiving CsA therapy and exhibiting CsA GO. Sixteen renal transplant patients receiving CsA, 12 patients with gingivitis, and 11 periodontally healthy subjects were included in this study. Data were obtained on plaque index, papilla bleeding index (PBI), and hyperplastic index from each study site. GCF samples and clinical data were obtained from: 1) 2 sites exhibiting CsA GO (CsA GO+) and 2 sites not exhibiting CsA GO (CsA GO-) in each CsA-treated patient; 2) diseased sites in each patient with gingivitis; and 3) 2 healthy sites in each subject with clinically healthy periodontium. CsA GO+ and CsA GO- sites were also divided into 2 subgroups as clinically uninflamed (PBI = 0) and inflamed (PBI > or = 1). The total amounts of cytokines in GCF were assayed by enzyme-linked immunosorbent assay. GCF IL-1beta levels were significantly higher in CsA GO+ sites compared to CsA GO-sites. Higher GCF levels of IL-1beta and IL-6 were detected in diseased sites compared to healthy sites. Although GCF IL-1beta levels in CsA GO+ sites were significantly higher than in the diseased sites, IL-6 levels of these sites were lower than in the diseased sites, whereas clinical degrees of gingival inflammation were similar in CsA GO+ and diseased sites. Additionally, while IL-1beta and IL-6 levels were similar in uninflamed CsA GO- sites and healthy sites, IL-1beta levels were significantly higher in uninflamed CsA GO+ sites compared to healthy sites and uninflamed CsA GO- sites. However, IL-1beta and IL-6 levels were significantly higher in inflamed CsA GO- sites compared to uninflamed CsA GO+ sites. No significant changes in GCF TNF-alpha levels were found between the groups. These data indicate that CsA therapy does not increase IL-1beta and IL-6 levels in GCF directly and that gingival inflammation plays a significant role in the elevation of GCF IL-1beta and IL-6 levels. For this reason, it is suggested that the alterations of GCF IL-1beta and IL-6 levels in CsA-treated patients might be responsible for the CsA-induced gingival overgrowth not by itself but also in combination with other factors associated with inflammation. To our knowledge, this is the first report describing the levels of cytokines in GCF of CsA-treated patients. We believe that further studies will contribute to the description of the pathogenesis of CsA-induced gingival overgrowth.

CD11b mRNA expression in neutrophils isolated from peripheral blood and gingival crevicular fluid

Adhesion molecule CD11b/CD18 expressed by neutrophils (PMNs) participates in cell migration and phagocytosis of C3bi derivatized bacteria. It is this phagocytic function that eliminates some of the known periodontal pathogens in periodontal pockets. In patients with advanced periodontitis, homotypic aggregation of crevicular fluid PMNs (CF-PMNs) may occur due to overexpression of CD11b/CD18 and this may lead to ineffective elimination of periodontal pathogens. We have previously shown that CF-PMNs isolated from the periodontal pockets overexpress CD11b compared to PB-PMNs. This study tested the hypotheses that (1) overexpression of surface CD11b correlates with expression of CD11b mRNA in CF-PMNs isolated from advanced periodontitis subjects, and (2) the intrinsic capacity of CD11b mRNA upregulation by PB-PMNs from periodontitis patients differs from that of control subjects. CF-PMNs and peripheral blood PMNs (PB-PMNs) were isolated from 13 subjects with healthy gingiva (control group) and 13 subjects with advanced periodontitis (patient group). The surface expression of CD11b was determined by flow cytometry and CD11b mRNA was determined by extraction of mRNA and reverse transcription to cDNA followed by DNA amplification using primers to detect a segment of the cDNA which encodes CD11b. The results of this study confirm that the surface expression of CD11b on CF-PMNs is significantly higher in periodontitis subjects vs control subjects (p = 0.03), whereas surface CD11b expression on PB-PMNs does not differ significantly between groups (p = 0.06). The level of surface CD11b expression on CF-PMNs did not correlate with the amount of mRNA present in CF-PMNs in either group (p = 0.056, 0.07 for control and periodontitis patients, respectively). Most (9 of 13) individuals in the patient group expressed CD11b mRNA whereas very few control subjects (2 of 11) had CD11b mRNA in their CF-PMNs. This difference between groups was statistically significant (p = 0.004). The capacity to upregulate CD11b mRNA upon stimulation with fMLP and/or GM-CSF was highly variable and there was no statistical difference between the 2 groups.

Cytokine production by oral and peripheral blood neutrophils in adult periodontitis

Proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin 1 beta (IL-1 beta) also possess bone-resorptive properties, and are generally considered to play a role in the pathogenesis of periodontal disease. In the present study, TNF-alpha and IL-1 beta production by oral and peripheral blood polymorphonuclear leukocytes (PMN) was examined in 40 patients with adult periodontitis and 40 orally healthy matched controls. Oral PMN released considerable amounts of both cytokines in unstimulated culture, and there was no difference between patients and controls when the cytokine levels were corrected for cell number. However, when the effect of disease activity was examined, cytokine release by oral PMN was found to be greatest in patients with advanced periodontitis. Within the healthy control group, IL-1 beta production by oral PMN was significantly higher in males (Mann-Whitney test, P = 0.0008). Examination of IL-1 beta production by peripheral blood PMN exposed to recombinant human granulocyte-macrophage colony stimulating factor revealed no difference between the patient and control groups. In contrast, IL-1 beta production by peripheral blood PMN was significantly reduced in patients with advanced disease (Mann-Whitney test, P = 0.02), and peripheral PMN IL-1 beta synthesis was greater in female controls (Mann-Whitney test, P = 0.054). No effect of race on cytokine production could be discerned in patients or controls. These results indicate that several factors influence cytokine production in oral health and disease, and that a dichotomy in cytokine gene expression exists between oral and peripheral blood PMN in adult periodontitis.

Gingival crevicular interleukin-1 and interleukin-1 receptor antagonist levels in periodontally healthy and diseased sites

Interleukin-1 (IL-1) molecules, IL-1 alpha and IL-1 beta are cytokines involved in the acute-phase response against infection and in the pathogenesis of periodontal destruction. Administration of exogenous IL-1 receptor antagonist (IL-1ra) is effective in reducing the inflammatory reactions mediated by IL-1. However, the relationship between these three naturally occurring IL-1 molecules and periodontal diseases has been poorly characterized. We investigated the correlation of gingival crevicular IL-1 molecules and the clinical status of patients with different severities of periodontitis. IL-1 alpha, IL-1 beta, IL-1ra and the total IL-1/IL-1ra ratio (IL-1 activity index; IL-1AI) were measured in 75 gingival crevicular fluid (GCF) samples from non-inflamed gingiva sites in 2 healthy subjects and diseased sites in 7 patients with several types of periodontitis. IL-1 alpha, IL-1 beta and IL-1ra were measured by specific non-cross-reactive enzyme linked immunosorbent assay. The probing depth, gingival index and alveolar bone loss of each site was recorded at the time of GCF sampling. The total amount of IL-1 alpha, IL-1 beta and the IL-1AI, but not total IL-1ra, were found to be correlated with alveolar bone loss score. Three IL-1 molecules were also measured in the gingival tissue of patients with periodontitis. A similar progressive decrease of the IL-1AI was detected in gingival tissue with periodontitis. These results suggest that the amounts of both crevicular IL-1 and IL-1AI are closely associated with periodontal disease severity.

Secretion of IL-1 beta, TNF-alpha, IL-8 and IL-1ra by human polymorphonuclear leukocytes in response to lipopolysaccharides from periodontopathic bacteria

Polymorphonuclear leukocytes (PMN) are the first cells that migrate into periodontal tissues and gingival crevices in response to invading pathogens. It was recently demonstrated that PMN have the ability to synthesize and release cytokines following appropriate stimulation, while it is not clear whether these capacities are directly related to periodontal destructive processes. We therefore investigated the amounts of the cytokines interleukin-1 beta (IL-1 beta), tumor necrosis factor alpha (TNF-alpha), IL-8 and IL-1 receptor antagonist (IL-1ra) secreted by PMN from healthy donors following stimulation with lipopolysaccharide (LPS) from 4 periodontopathic bacteria, Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans, Capnocytophaga ochracea and Fusobacterium nucleatum, and the non-oral bacterium Escherichia coli. A actinomycetemcomitans, F. nucleatum and E. coli LPS stimulated the release of significantly greater amounts of IL-1 beta, TNF-alpha and IL-8 than the control unstimulated PMN (p < 0.01). The levels of IL-1 beta, TNF-alpha and IL-8 released from cells stimulated with P. gingivalis or C. ochracea LPS were significantly lower than those of cells stimulated with A. actinomycetemcomitans or E. coli LPS (p < 0.05). On the other hand, substantially greater amounts of IL-1ra were released from PMN stimulated with each LPS and from control unstimulated PMN during the first 6 h, and then significantly greater amounts of IL-1ra were secreted by PMN stimulated with A. actinomycetemcomitans and E.coli LPS during the following 12 h (p < 0.01). The inhibitory effects of IL-1ra on the biological activity of IL-1 in the supernatants of PMN were examined by the thymocyte comitogen proliferation assay. The supernatants of PMN stimulated with each LPS showed less biological IL-1 activity as compared with the same doses of recombinant human IL-1 beta detected by enzyme-linked immunosorbent assay. Furthermore, no activity was detected in the supernatants of PMN stimulated with P. gingivalis or C. ochracea LPS. These findings demonstrated that LPS from periodontopathic bacteria were capable of stimulating PMN to release not only pro-inflammatory cytokines but also their inhibitors such as IL-1ra. Different secretion levels of these cytokines and their biological activities induced by the various LPS might be important in the onset and progression of periodontal diseases.

Interleukin-8 and beta-glucuronidase in gingival crevicular fluid

Polymorphonuclear leukocytes (PMN) play a critical role in the host's response to the subgingival microflora. Interleukin-8 (IL-8) is a potent chemotactic and activating factor for PMN. In this study, the presence of IL-8 in gingival crevicular fluid (GCF) was examined in relation to the PMN indicator beta-glucuronidase (beta G), as well as clinical parameters of chronic inflammatory periodontal disease. Data was obtained from 30 patients with periodontitis and 14 healthy controls. For the control group, GCF and clinical data were obtained only once. For the periodontitis patients, clinical data and GCF samples were collected prior to treatment, and GCF samples were again collected 2 weeks after scaling and root planing. Comparing control and periodontitis patients prior to treatment, IL-8 concentration was lower in the patients with periodontitis. Scaling and root planing resulted in either an increase or a decrease in total IL-8 and IL-8 concentration GCF. A reduction in total IL-8 or IL-8 concentration was accompanied by a corresponding reduction in beta G activity. An increase in total IL-8 or IL-8 concentration after scaling and root planing was associated with an increase in beta G activity in some patients and a reduction in beta G activity in other patients. The periodontitis patients who did not demonstrate a linkage between IL-8 and beta G activity in GCF were those individuals with the highest beta G activity prior to treatment. As elevated beta G activity in GCF has been associated with an increased risk for probing attachment loss, the absence of a direct relationship between IL-8 in GCF and PMN recruitment into the gingival crevice may characterize individuals at risk for progression of periodontitis.

Cytokine production by cells adherent to regenerative membranes

Since cytokines play a critical role in tissue regeneration, we have assayed cytokine production by cells from tissue adherent to regenerative membranes. Cells were recovered from Gore-tex membranes in guided tissue regeneration (GTR) procedures to regenerate that attachment apparatus around teeth and from Gore-tex augmentation membranes (GTAM) used for guided gone regeneration (GBR) procedures in edentulous ridge augmentation with or without implant placement. Cells were screened for mineralized nodule formation in vitro to mRNA analysis to demonstrate that they could form mineralized tissue. Production in interleukin-1 alpha (IL-1 alpha) interleukin-1 beta (IL-1 beta), interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) was evaluated by reverse transcribed-polymerase chain reaction (RT-PCR) of mRNA from rescued regenerative cells, human gingival fibroblasts and periodontal ligament (PDL) cells. Both the gingival fibroblast and PDL cells isolates produced all 4 cytokines. However, the cell isolates from the regenerative membranes had various profiles of cytokine expression. Most GTR cell isolates were positive for all 4 cytokines. IL-1 beta was produced by all 6 GTR cell isolates but was not detected at the same number of cycles of RT-PCR amplification in any of the 6 GBR cell isolates. IL-1 beta transcripts were also not observed in cells derived from a direct biopsy of GBR tissue. Cells were recovered from unexposed GBR membranes did not produce detectable amounts of IFN-gamma, whereas cells recovered from exposed GBR and all GTR membranes produced IFN-gamma. These findings indicate that cells from regenerative tissues express different cytokines and that exposure to the tissue to the oral cavity during healing may modulate this expression.

Factors affecting IL-1-mediated collagen metabolism by fibroblasts and the pathogenesis of periodontal disease: a review of the literature

Fibroblasts have been studied extensively for their contribution to connective tissue destruction in diseases where the metabolism of extracellular matrix components plays an essential part in their pathogenesis. A considerable dissolution, especially of collagen fibrils, is a well-known characteristic of the periodontal ligament and the gingival connective tissue in microbial-induced periodontal disease. Fibroblasts, responsible for the assembly of the extracellular matrix, are capable of responding directly to oral microbial challenges or indirectly, following activation of the host immune response, and can alter the composition of connective tissue in several ways: synthesis of inflammatory mediators, their receptors and antagonists; fibroblast proliferation; collagen synthesis; phagocytosis of collagen fibrils; and synthesis of proteolytic enzymes, including matrix metalloproteinases and their corresponding inhibitors. The contributions of these cellular fibroblastic properties to the pathogenesis of periodontal disease are reviewed in the context of the cytokine, interleukin-1, as the inflammatory regulator.