Effects of interleukin 1 beta, tumor necrosis factor alpha and transforming growth factor beta on group II phospholipase A2 activity in rat gingival fibroblasts

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

AIM

BACKGROUND AND OBJECTIVES

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

METHODS

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

RESULTS

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

INTERPRETATION AND CONCLUSION

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

CLINICAL SIGNIFICANCE

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

Measurement of prostaglandin E2 and leukotriene B4 in the gingival crevicular fluid

The arachidonic acid metabolites prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) are inflammatory mediators which are likely to be involved in the pathogenesis of periodontal disease. PGE2 mediates vasodilatation, increases vascular permeability, enhances pain perception by bradykinin and histamine, alters connective tissue metabolism and enhances osteoclastic bone resorption. LTB4 causes the accumulation of inflammatory cells in the inflamed sites, and degranulation of polymorphonuclear leukocytes.

OBJECTIVE

To measure gingival crevicular fluid (GCF) levels of PGE2, LTB4 and periodontal health.

METHODS

The periodontal condition of 24 subjects was evaluated on the basis of plaque index, gingival index, probing depth, and attachment level. GCF samples were collected from one or two site(s) of each sextant per subject and the volume was measured using Periotron 6000. Samples were then assayed for PGE2 and LTB4 using a competitive enzyme immunoassay. Mean PGE2 and LTB4 levels were determined for each subject and group means compared.

RESULTS

Significant differences in the levels of PGE2 and LTB4 were found between patients with periodontitis, and non-periodontitis individuals (P < 0.001). The PGE2/LTB4 levels were positively correlated with the clinical parameters (P < 0.01) and reduced markedly after phase 1 of the periodontal treatment (P < 0.01). The total amount and concentration (ng ml-1) of LTB4 was positively correlated with the gingival index (P < 0.01).

CONCLUSIONS

These results indicate that the levels of PGE2 correlated with the severity of the periodontal status, and the levels of LTB4 correlated with gingival inflammation. Thus, our data suggest that the total amounts of PGE2/LTB4 may be good indicators for periodontal inflammation.

Cyclosporin A upregulates prostaglandin E2 production in human gingival fibroblasts challenged with tumor necrosis factor alpha in vitro

The effect of cyclosporin A (CsA) on prostaglandin E2 (PGE2) production in human gingival fibroblasts challenged with tumor necrosis factor alpha (TNF-alpha) was studied. TNF-alpha (1-100 ng/ml) dose-dependently stimulated PGE2 formation in 24 h cultures. CsA (1-100 ng/ml) did not induce PGE2 formation itself but potentiated TNF-alpha induced PGE2 formation in gingival fibroblasts in a manner dependent on the concentrations of both CsA and TNF-alpha. TNF-alpha (10 ng/ml) stimulated the release of [3H]-arachidonic acid (AA) from prelabelled fibroblasts that was potentiated by CsA (100 ng/ml). Addition of exogenous unlabelled AA (5-20 microM/ml) to the cells resulted in enhanced PGE2 formation that was not potentiated by CsA (100 ng/ml). Furthermore, CsA (100 ng/ml) did not further increase the level of cyclooxygenase-2 mRNA induced by TNF-alpha (10 ng/ml), although PGE2 formation was enhanced. The results indicate that CsA and TNF-alpha act in concert on PGE2 formation in gingival fibroblasts, which may be of importance in the pathogenesis of gingival overgrowth induced by the drug.

Effect of phenytoin on interleukin-1 beta production in human gingival fibroblasts challenged to tumor necrosis factor alpha in vitro

Effects and interaction of tumor necrosis factor alpha (TNF alpha) and the antiepileptic drug phenytoin (PHT) on interleukin-1 beta (IL-1 beta) production as well as on prostaglandin E2 (PGE2) formation were studied in gingival fibroblasts in vitro. TNF alpha, in contrast to PHT, dose-dependently stimulated the production of cell-associated IL-1 beta. The stimulatory effect of TNF alpha on IL-1 beta production was accompanied by enhanced PGE2 formation. When PHT and TNF alpha were added simultaneously, the drug potentiated the stimulatory effect of TNF alpha on both IL-1 beta production and PGE2 formation. The major PHT metabolite, p-HPPH, did not affect IL-1 beta production, either alone or in combination with TNF alpha. The production of IL-1 beta induced by TNF alpha and the combination of TNF alpha and PHT was further enhanced in the presence of the prostaglandin endoperoxide (PGH) synthase inhibitors, indomethacin and flurbiprofen. The PHT-mediated enhancement of TNF alpha-induced IL-1 beta production and PGE2 formation in gingival fibroblasts may be an important link in the pathogenesis of gingival overgrowth induced by PHT.

Induction of cytokine synthesis and fever suppresses REM sleep and improves mood in patients with major depression

Beneficial effects of inflammatory events on certain psychiatric disorders, including depression, were reported sporadically by ancient Greek physicians, but have been described also in our times by a few psychiatrists during the past decades. During febrile inflammatory events, mediators of the immune system such as interleukin-1 can be detected in the brain and may act on their respective receptors which have also been demonstrated in the brain. Since cytokines such as interleukin-1 have been shown in animal studies to exert sedative behavioral effects, to be somnogenic, and to induce slow-wave sleep (SWS), we performed a pilot study to evaluate scientifically the anecdotically reported beneficial effects of inflammatory states on depressive disorders. Mood and sleep parameters were monitored in seven drug-free, severely depressed patients before, during, and after the administration of a single dose of endotoxin. All patients responded with a short pulse of increased synthesis of the cytokines tumor necrosis factor, interleukin-1, and interleukin-6 and elevated body temperature for several hours. During the night following endotoxin administration, rapid eye movement (REM) sleep was significantly suppressed, while changes in slow wave sleep were not significant. During the next day, all patients were in a significantly improved mood; however a rebound of REM sleep was observed in the second night after endotoxin administration and mood worsened again during the next days, indicating an only transient beneficial effect of the treatment.

Group II phospholipase A(2) in human gingiva with periodontal disease

Fourteen kilodalton phospholipase A₂ molecules (PLA₂) are classified into two groups, I- and II-PLA₂, and only the latter has been considered to play a pathogenetic role in various forms of tissue inflammation. Previously we demonstrated high PLA₂ activity in gingival crevicular fluid (GCF) of patients with periodontal disease, without determining the group of the enzyme involved. In this study, the activity, groups and levels of enzyme in gingiva taken from 13 sites of periodontal disease were determined using both biochemical and radioimmunological methods. A linear correlation between the activity and the level of II-PLA₂ was observed. No I-PLA₂ was found in any of the samples tested. These data suggest that the PLA₂ activity found in the GCF of patients with periodontal disease does not belong to the I-PLA₂ but to the II-PLA₂ group.

Enhanced expression of group II phospholipase A2 in human hepatocellular carcinoma

Enzyme activity, protein contents, and mRNA contents of group II phospholipase A2 (PLA2) in hepatocellular carcinoma (HCC) surgically obtained from 8 patients were compared with those in either its neighboring liver tissues or control liver tissues. The PLA2 specific activity towards the mixed micelles of 1-palmitoyl-2-oleoyl-phosphatidylglycerol and cholate was significantly greater in the tumor tissues (6.62 +/- 1.46 nmol/min/mg) than those in the surrounding liver tissues (1.33 +/- 0.22 nmol/min/mg) and controls (0.43 +/- 0.04 nmol/min/mg). The results of immunoblot analysis using a specific anti-human group II PLA2 antibody and of Northern blot analysis using a human group II PLA2 cDNA as a probe demonstrated that group II PLA2 was responsible for the increased enzyme activity. The contents of immunoreactive group II PLA2 in the tumor tissues (8.81 +/- 1.24 ng/mg) were significantly higher than those in the surrounding liver tissues (1.74 +/- 0.27 ng/mg); those in the control tissues were below the analytical range of the method used. The group II PLA2 mRNA was also significantly increased in the tumor tissues, compared with that in the surrounding liver tissues, whereas it was not detectable in the controls. This indicates that group II PLA2 in HCC is induced at the pretranslational level.