Stimulation by interleukin-1 of interleukin-6 production by human periodontal ligament cells.

Interleukin-1(IL-1), a cytokine present in the gingiva and crevicular fluid of patients with periodontitis and in the periodontal ligament (PDL) of experimentally moved teeth, has multiple biological activities, including the ability to elicit bone resorption. Interleukin-6, also found in the gingiva of patients with periodontitis, may induce osteoclastic bone resorption through an effect on osteoclastogenesis. Here IL-6 production and its gene expression in response to recombinant IL-1 beta were examined in primary cultures of PDL cells. IL-1 beta stimulated IL-6 production by these cells in a dose- and time-dependent manner; this increase in IL-6 production was much higher than that in human gingival fibroblasts. In situ hybridization, using a synthetic oligonucleotide DNA probe of the IL-6 gene, revealed that most PDL cells expressed IL-6 mRNA in response to IL-1 beta treatment. The finding that IL-6 is produced by PDL cells and is regulated by IL-1 beta has revealed a potentially important mechanism for controlling alveolar bone resorption.     

Actinobacillus actinomycetemcomitans-induced expression of IL-1α and IL-1β in human gingival epithelial cells: role in IL-8 expression

Gingival epithelial cells (GEC) are the first cells of the host that encounter the periodontal pathogens. and therefore their role in the initiation of the inflammatory response is critical. We aimed to: 1) characterize the expression of interleukin (IL)- Ialpha and IL-Ibeta in human gingiva and cultured GEC: 2) demonstrate the ability of A. actinomycetemcomitans extracts to upregulate IL-1alpha, IL-1beta and IL-8 expression in GEC in vitro: and 3) characterize the role of IL-1alpha and IL-1beta in the induction of IL-8 expression in GEC in vitro. Ten gingival biopsies (5 inflamed and 5 controls) and cultured GEC were examined for IL-1alpha and IL-Ibeta using immunohistochemical techniques. GEC were also challenged with A. actinomycetemcomitans extracts or IL-1alpha, and secretion of IL-1 and IL-8 was determined by ELISA. In vivo, IL-lalpha and IL-1beta were localized in the gingival epithelium and the infiltrating leukocytes. In vitro, A. actinomycetemcomitans extracts induced a time-dependent expression of IL-1alpha, IL-1beta and IL-8 in GEC. IL-1 inhibitors did not affect A. actinomycetemcomitans-induced IL-8. although they inhibited IL-8 induced by IL-1alpha or IL-1beta. In conclusion, GEC are a major source of IL-1alpha and IL-1beta in the periodontium, which in turn induce additional inflammatory mediators such as IL-8. Therefore GEC can be a potential target for therapeutic intervention in the future.     

Keratinocyte growth factor (KGF)-1 and -2 protein and gene expression in human gingival fibroblasts

The onset and progression of periodontal disease is associated with significant changes in the epithelial component of the attachment complex. From the early to the advanced stages of periodontal disease increased epithelial cell proliferation, migration and invasion into the surrounding connective tissue takes place. Concomitantly there is a significant increase in proinflammatory cytokine expression in periodontal tissue and quantitative and qualitative changes in the subgingival microflora, including an increase in gram-negative microorganisms. One of the most significant virulence factors of these bacteria is lipopolysaccharide (LPS) connected to the outer membrane. Two important growth factors controlling epithelial behavior are Keratinocyte Growth Factor-1 (KGF-1) and -2 (KGF-2). Connective tissue cells express these growth factors, but only epithelial cells respond to them. We studied the effect of proinflammatory cytokines and LPS on gingival fibroblast expression of KGF-1 and KGF-2 in vitro. Gingival fibroblasts were found to express KGF-1 and -2 in culture but only KGF-1 protein and gene expression was stimulated by serum, in a concentration-dependent manner by proinflammatory cytokines IL-1alpha, IL-1beta, TNF-alpha and IL-6 and LPS isolated from Porphyromonas gingivalis and Escherichia coli. The local increase in proinflammatory cytokine expression and the accumulation of LPS in disease sites may therefore stimulate gingival fibroblast expression of KGF-1. We hypothesize that this local increase in KGF-1 expression may, via a paracrine mechanism, stimulate local epithelial cell proliferation, migration and invasion during the onset and progression of periodontitis.     

Polymorphonuclear neutrophils and their mediators in gingival tissues from generalized aggressive periodontitis.

BACKGROUND: Impaired polymorphonuclear neutrophil (PMN) functions were generally considered to be related to the onset of generalized aggressive periodontitis (GAgP). However, some research has indicated that the hyperreactivity of PMN seems to be involved in the inflammatory response of GAgP. The present study's main purpose was to provide more evidence about the role of PMN in the pathogenesis of GAgP by surveying PMN infiltration in gingiva and its relationship with the expression of their mediators including intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The inflammatory response in GAgP was also compared with that in adult periodontitis (AP) and periodontally healthy subjects. Since these PMN mediators were reported to be produced mainly by macrophages, the association between the expression of these PMN mediators and the distribution of macrophages was also investigated. METHODS: A total of 25 gingival specimens were obtained from 10 GAgP patients, 10 AP patients, and 5 periodontally healthy subjects. Serial sections were obtained from each specimen, and the following techniques were adopted to investigate the distribution and interrelation of different cells and cytokines. Infiltration of PMN was observed by using hematoxylin and eosin staining. Distribution of the macrophages, identified as CD68+, was shown by using immunohistochemistry. Immunohistochemistry and in situ hybridization were used to detect the expression of ICAM-1, IL-8, IL-1beta, and TNF-alpha in gingival tissues. These techniques were performed in serial sections from each individual specimen. RESULTS: Large numbers of infiltrating PMNs were observed in gingiva from GAgP. In gingiva from both GAgP and AP, the strongest protein and mRNA expression of IL-8, ICAM-1, IL-1beta, and TNF-alpha were located in pocket epithelium and adjacent connective tissue with large numbers of infiltrating PMNs. In tissues without abundant PMN infiltration, the appearance of positive cells expressing IL-8, ICAM-1, IL-1beta, and TNF-alpha was scattered. CD68+ was distributed sparsely in connective tissue and was hardly seen in pocket epithelium with large numbers of PMN infiltration. The degree of leukocyte infiltration and connective tissue destruction in gingiva from GAgP patients was not distinctly different from that in gingiva from AP. The gingival specimens with heavy PMN infiltration from both GAgP and AP patients presented strong expressions of IL-1beta and TNF-alpha; showed more extensive inflammatory cell infiltration; had severe connective tissue destruction; and presented severe elongation and ulceration of pocket epithelium. In gingiva from healthy subjects, inflammation was minor with visually no PMN, CD68+, or the positive cells of IL-8, ICAM-1, IL-1beta and TNF-alpha expression. CONCLUSIONS: Enhanced accumulation of PMN, which is associated with the upregulation of IL-8, ICAM-1, IL-1beta, and TNF-alpha expression, relates to the severity and activity of GAgP. In addition to macrophages, PMN and/or epithelial cells might also be important sources of IL-8, IL-1beta, and TNF-alpha production in gingiva.     

Th2 cytokines efficiently stimulate periostin production in gingival fibroblasts but periostin does not induce an inflammatory response in gingival epithelial cells

Objectives

This study aims to clarify whether gingival fibroblasts produce periostin in response to Th2 cytokines which are elevated in periodontitis lesion and, if so, whether periostin affects the inflammatory response and matrix-protein metabolism.

Design

Human gingival fibroblasts, periodontal ligament cells and the gingival epithelial cell line epi4 were stimulated with interleukin-4 (IL-4), IL-13, tumour necrosis factor-α (TNF-α) and Porphyromonas gingivalis lipopolysaccharide (LPS). Periostin expression was analysed by real-time polymerase chain-reaction (PCR) and Western blotting. The expression of the IL-4 receptor α-chain was evaluated by immunocytochemistry. The effect of periostin on the production of inflammatory cytokines and the expression of matrix protein-related genes was analysed by real-time PCR and enzyme-linked immunosorbent assay (ELISA).

Results

While IL-4 and IL-13 significantly induced periostin production in gingival fibroblasts and periodontal ligament cells, no effect was observed in epi4 cells. No stimulatory effect of TNF-α or P. gingivalis LPS on the production of periostin was observed. The effect of periostin on the production of inflammatory cytokines was weak in gingival fibroblasts; however, little or no effect was observed on periodontal ligament cells or epi4 cells. No significant effect of periostin on the expression of matrix protein-related genes was found.

Conclusion

The results suggest that gingival fibroblasts may be a source of periostin in periodontitis lesions but periostin has only a limited role either in the inflammatory response or in matrix-protein metabolism. Thus, the role of periostin in the cellular interaction between epithelial and mesenchymal cells in gingiva may be distinct from that of skin.     

Soluble CD14-dependent intercellular adhesion molecular-1 induction by Porphyromonas gingivalis lipopolysaccharide in human gingival fibroblasts.

BACKGROUND: Intercellular adhesion molecule-1 (ICAM-1) is involved in the accumulation and activation of leukocytes in inflammatory sites through binding to beta2 integrins expressed on leukocytes. We investigated whether or not lipopolysaccharide (LPS) derived from the periodontopathic bacterium Porphyromonas gingiualis affects ICAM-1 expression on human gingival fibroblasts (HGF). CD14 is a receptor for LPS on monocytes and macrophages and is also present in serum as a soluble protein. We further examined the effects of serum and soluble CD14 (sCD14) on ICAM-1 expression in HGF stimulated with P. gingivalis LPS. METHODS: HGF were prepared from explants of human gingival tissues and incubated in 96-well culture plates before LPS stimulation. LPS derived from Escherichia coli O55:B5 and P. gingivalis ATCC 33277 LPS were employed. sCD14 was purified from normal human serum (NHS) by affinity chromatography using an anti-CD14 monoclonal antibody. ICAM-1 expression on HGF was measured by a cell enzyme-linked immunosorbent assay. RESULTS: P. gingivalis LPS induced ICAM-1 on HGF in a dose-dependent manner in the presence of either 10% fetal calf serum or 2% NHS. The ability of P. gingivalis LPS to induce ICAM-1 was comparable to that of LPS from E. coli at high LPS concentrations. In the absence of NHS, ICAM-1 induction was negligible in HGF stimulated with P. gingivalis LPS, reaching a maximum at 2% NHS. The ICAM-1 expression induced by P. gingivalis LPS was inhibited by a monoclonal antibody to CD14. Supplementation of serum-free medium with sCD14 alone restored the capacity of HGF to respond to P. gingivalis LPS. CONCLUSIONS: These results indicate that P. gingivalis LPS induces ICAM-1 expression in HGF in an sCD14-dependent manner. The overexpression of ICAM-1 on fibroblasts in gingiva induced by P. gingivalis LPS seems to be involved in the retention of inflammatory cells in periodontitis lesions.     

Lipopolysaccharide from Actinobacillus actinomycetemcomitans stimulates macrophages to produce interleukin-1 and tumor necrosis factor mRNA and protein

Actinobacillus actinomycetemcomitans is associated with periodontal disease in children and adults. We report that low concentrations of lipopolysaccharide (LPS) from A. actinomycetemcomitans stimulated human macrophages to increase dramatically their accumulation of mRNA coding for interleukin-1 alpha (IL-1 alpha), IL-1 beta as well as tumor necrosis factor (TNF). Protein levels of IL-1 and TNF alpha also increased. Levels of these mRNAs increased by 4-5 fold as compared with unstimulated macrophages when these cells were cultured with as little as 2 ng/ml LPS from A. actinomycetemcomitans. Polymyxin binds and blocks the action of LPS; polymyxin inhibited the ability of LPS from A. actinomycetemcomitans to increase levels of IL-1 beta mRNA. The LPS of A. actinomycetemcomitans stimulated increased levels of IL-1 beta mRNA in the presence of cycloheximide, showing that stimulation by this LPS did not require new synthesis of protein. Furthermore, dexamethasone inhibited the ability of LPS from A. actinomycetemcomitans to stimulate the accumulation of mRNA coding for IL-1 beta. A. actinomycetemcomitans is an invasive microorganism of the gingiva; high intragingival numbers correlate with sites undergoing local destruction of the periodontium. IL-1 alpha, IL-1 beta, and TNF are potent monokines that mediate inflammation and resorption of bone. Out studies suggest that macrophages migrating to these gingival sites of A. actinomycetemcomitans infection will be stimulated by LPS of A. actinomycetemcomitans to produce IL-1 alpha, IL-1 beta and TNF. These cytokines will mediate gingival inflammation and stimulate resorption of alveolar bone.     

The role of IL-1 beta and TNF-alpha in hyper-reactivity of neutrophils in rapidly progressive periodontitis patients]

OBJECTIVE: Neutrophils (PMNs) from rapidly progressive periodontitis (RPP) was found to generate abnormally high levels of oxygen radicals. Elastase activity in gingival crevicular fluid (GCF) from RPP was also found much higher. It suggested that PMNs in some RPP patients are hyper-reactive. The purpose of this study was to investigate the mechanism of PMN hyper-reactivity by surveying the correlation of TNF-alpha level with elastase activity in GCF and by evaluating the association between PMN infiltration and the expression of IL-1 beta and TNF-alpha in gingival tissues from RPP patients. METHODS: 41 GCF samples from 22 RPP patients and 34 GCF samples from 11 healthy controls were collected. The total amount of TNF-alpha in GCF was detected using ELISA. The elastase activity was measured with a low molecular weight substrate (S2484) specific for granulocyte. The correlation of TNF-alpha level with elastase activity in a GCF sample was analyzed with Spearman correlation. 20 gingival specimens were obtained respectively from 10 RPP patients and 5 periodontally healthy controls. The expression of IL-1 beta and TNF-alpha was detected with immunohistochemistry. The distribution of PMN was observed with hematoxylin and eosin staining. RESULTS: Total amount of TNF-alpha in GCF was positively correlated with elastase activity (r = 0.44, P < 0.05). The IL-1 beta- and TNF-alpha-positive cells in gingiva were superimposed in areas where PMNs infiltration predominant. CONCLUSION: The hyper-reactivity of PMN in RPP patients was related to locally produced IL-1 beta and TNF-alpha.     

Retinoic acid-inducible gene-I is induced in gingival fibroblasts by lipopolysaccharide or poly IC: possible roles in interleukin-1beta, -6 and -8 expression

Retinoic acid-inducible gene-I (RIG-I) is a member of the DExH family of proteins, and little is known of its biological function in the oral region. We previously reported that interleukin 1beta (IL-1beta) induced RIG-I expression in gingival fibroblasts. In this study, we studied the mechanism of RIG-I expression induced by lipopolysaccharide (LPS) or double-stranded RNA (dsRNA) in gingival fibroblasts. We also addressed the role of RIG-I in the expression of IL-1beta, IL-6 and IL-8 in gingival fibroblasts stimulated with LPS or dsRNA. We stimulated cultured human gingival fibroblasts with LPS or dsRNA, and examined the expression of RIG-I mRNA and protein. The effect of cycloheximide, a protein synthesis inhibitor, on RIG-I induction by these stimuli was examined. The expression of IL-1beta, IL-6 and IL-8 in gingival fibroblasts transfected with RIG-I cDNA stimulated with LPS or dsRNA was examined. LPS or dsRNA induced the expression of mRNA and protein for RIG-I in concentration- and time-dependent manners. We also examined the localization of RIG-I, and found that it was expressed in cytoplasm. Cycloheximide did not suppress the LPS or dsRNA-induced RIG-I expression. Introduction of RIG-I cDNA into gingival fibroblasts resulted in enhanced expression of IL-1beta, IL-6 and IL-8; moreover, overexpression of RIG-I stimulated with LPS or dsRNA synergistically increased expression of IL-1beta, IL-6 and IL-8. RIG-I may have important roles in the innate immune response in the regulation of IL-1beta, IL-6 and IL-8 expression in gingival fibroblasts in response to LPS and dsRNA.     

Intracellular interleukin-1 alpha production in human gingival fibroblasts is differentially regulated by various cytokines.

Interleukin-1 (IL-1) may play a critical role in immune and inflammatory responses in inflamed gingiva, and it is synthesized by a wide variety of host cells. In this study, we examined the regulatory effects of various cytokines on bioactive membrane IL-1 and intracellular IL-1 alpha production in cultured human gingival fibroblasts (HGF). Recombinant human (rh) IL-1 beta stimulated membrane IL-1 activity, which was mainly attributed to IL-1 alpha. rhIL-1 beta and rh tumor necrosis factor (TNF)-alpha stimulated HGF to produce intracellular IL-1 alpha, whereas rh interleukin-6 (IL-6), rh interleukin-4 (IL-4), and rh interferon (IFN)-gamma did not do so. Intracellular IL-1 alpha production induced by rhIL-1 beta or rhTNF-alpha may be partially related to protein kinase C (PKC) activation, because rhIL-1 beta or rhTNF-alpha-induced intracellular IL-1 alpha production was stimulated by pre-treatment with 12-o-tetradecanoylphorbol 13-acetate (TPA), a PKC activator, but was suppressed by the pre-treatment with 1-(5-isoquinoline-sulfonyl) -2-methylpiperazine dihydrochloride (H-7), which is a PKC inhibitor. rhIL-4 inhibited rhIL-1 beta- or rhTNF-alpha-induced intracellular IL-1 alpha production, but rhIL-6 had no effect on this production. Pre-treatment with rh IFN-gamma remarkably enhanced intracellular IL-1 alpha production induced by subsequent treatment with rhIL-1 beta or rhTNF-alpha. Simultaneous treatment with rhIFN-gamma and rhIL-1 beta inhibited rhIL-1 beta-induced intracellular IL-1 alpha production, but co-treatment with rhIFN-gamma and rhTNF-alpha enhanced rhTNF-alpha-induced intracellular IL-1 alpha production. These results suggest that in inflamed gingiva, pro-inflammatory cytokines such as IL-1 beta and TNF-alpha may induce bioactive intracellular IL-1 alpha production in human gingival fibroblasts and that this production can be differentially modulated by T-cell-derived cytokines such as IFN-gamma or IL4.     

IL-1beta and TNF-alpha regulate IL-6-type cytokines in gingival fibroblasts

Interleukin-6 (IL-6)-type cytokines are pleiotropic molecules capable of stimulating bone resorption and expressed by numerous cell types. In the present study, we tested the hypothesis that gingival fibroblasts may exert local osteotropic effects through production of IL-6 and related cytokines. IL-6-type cytokine expression and regulation by IL-1beta and tumor necrosis factor-alpha (TNF-alpha) were studied in fibroblasts from the non-inflamed gingiva of healthy individuals. Constitutive mRNA expression of IL-6, IL-11, and leukemia inhibitory factor (LIF), but not of oncostatin M (OSM), was demonstrated, as was concentration-dependent stimulation of IL-6 and LIF mRNA and of protein by IL-1beta and TNF-alpha. IL-11 mRNA and protein were concentration-dependently stimulated by IL-1beta. The signaling pathway involved in IL-6 and LIF mRNA stimulation involved MAP kinases, but not NF-kappaB. The findings support the view that resident cells may influence the pathogenesis of periodontal disease through osteotropic IL-6-type cytokine production mediated by activation of MAP kinases. Abbreviations: IL-1alpha (interleukin-1alpha); IL-1beta (interleukin-1beta); IL-6 (interleukin-6); IL-11 (interleukin-11); LIF (leukemia inhibitory factor); OSM (oncostatin M); alpha(1)-coll. I (alpha(1)-collagen I); ALP (alkaline phosphatase); BMP-2 (bone morphogenetic protein-2); OC (osteocalcin); BSP (bone sialoprotein); TNFR I (tumor necrosis factor receptor I); TNFR II (tumor necrosis factor receptor II); IL-1R1 (interleukin-1 receptor 1); GAPDH (glyceraldehyde-3-phosphate dehydrogenase); RPL13A (ribosomal protein L13A); mRNA (messenger ribonucleic acid); cDNA (complementary deoxyribonucleic acid); PCR (polymerase chain-reaction); BCA (bicinchoninic acid); ELISA (enzyme-linked immunosorbent assay); alpha-MEM (alpha modification of Minimum Essential Medium); and FCS (fetal calf serum).     

Study of cytokine production in inflamed human gingival tissues in periodontitis. Interleukin-1 (IL-1 alpha, beta) and tumor necrosis factor (TNF alpha)

It seems to be generally agreed that periodontal disease is a local manifestation of a systemic immune response. Interleukin-1 (IL-1), which has multiple biologic activities, is detected in the gingival sulcus fluid of periodontitis sites. Recent investigations have revealed that IL-1 and tumor necrosis factor (TNF) are analogous to osteoclast activating factor and promote bone resorption. These findings have suggested the possibility that IL-1 and TNF may play a significant role in the initiation and development of periodontal disease. However, it remains to be determined whether these cytokines influence periodontal tissue breakdown in periodontitis. To elucidate the mechanisms of tissue breakdown in periodontitis, we examined cytokine production by human periodontitis gingival tissue. Twelve periodontitis patients were included in this study. Control subjects with healthy periodontium consisted of nine individuals. Gingival samples were biopsied from inflamed or healthy gingival tissues. Biopsy specimens were dissected into fragments 3 mm in diameter and plated onto 24 well culture plates with RPMI 1640 medium. IL-1 activity was measured by a growth inhibition assay using melanoma cell line A 375. An enzyme-linked immunosorbent assay (ELIZA) was used for measuring levels of human IL-1 alpha, IL-1 beta. TNF alpha activity was measured by a growth inhibition assay using cell line LM2D6. IL-1 activity was detected in significantly (p less than 0.001) higher levels in culture supernatants from gingival tissues in periodontitis (48.0 +/- 23.3 units/ml) than in control tissues (2.3 +/- 0.6 units/ml), however, levels of IL-1 activity were not associated with periodontal pocket depth or extent of alveolar bone resorption in periodontitis.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aspects of interleukin-8 gene expression by gingival and dermal fibroblasts stimulated with interleukin-1beta or tumour necrosis factor alpha

Fibroblast-derived interleukin (IL)-8 is thought to have an important role in the orchestration of immuno-participant cells infiltrating the skin and gingiva in response to continuously recurring bacterial infection. Therefore, the IL-8 gene expression should be under tight regulatory control and it might be temporally and spatially limited in inflammatory tissue. The purpose of this study was to examine the aspect of the IL-8 gene expression by fibroblasts stimulated with pro-inflammatory cytokines, IL-1beta and TNF-alpha. In situ hybridisation revealed that fibroblasts did not express IL-8 mRNA whereas keratinocytes and endothelial cells did in IL-1beta- or TNF-alpha-injected mice skin. However, cultured mouse dermal fibroblasts expressed not only IL-8 but also IL-1beta mRNA without stimulation by exogenous IL-1beta and TNF-alpha, and the expression was not enhanced by the exogenous cytokines. A similar result was obtained in late-passage human gingival fibroblasts. These results suggest that fibroblasts remain insensitive to IL-1beta and TNF-alpha so as to induce the IL-8 gene expression in non-inflammatory mice skin. Mouse dermal and late-passage human gingival fibroblasts in vitro are likely to be altered in phenotype into IL-8-producing cells along with the production of IL-1beta. In skin inflammation and periodontal diseases, fibroblasts may express the IL-8 gene even without an exogenous cytokine, IL-1beta or TNF-alpha, during their proliferation similar to the situation in our culture system.     

Bone resorption and local interleukin-1alpha and interleukin-1beta synthesis induced by Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis lipopolysaccharide

Different types of periodontopathic bacterial lipopolysaccharide (LPS) exert various biological activities in vitro. However, whether or not these activities also occur in vivo remains unclear. Thus the present study investigates bone resorption, as well as local IL-1alpha and IL-1beta synthesis induced by Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis LPS in the periodontal tissue of mice. Both types of LPS were injected into mouse gingiva every 48 h and the animals were sacrificed 6 h after the 1st. 4th, 7th, 10th, 13th, 16th, 20th, or 24th injection. Bone resorption in the injected gingiva was histopathologically and histomorphometrically investigated and local concentrations of IL-1alpha and IL-1beta were detected using an enzyme-linked immunosorbent assay. The active resorption ratio was significantly higher in the group given the 10th injection of LPS from A. actinomycetemcomitans than in the group given P. gingivalis LPS. Furthermore, A. actinomycetemcomitans LPS stimulated significantly more synthesis of IL-1alpha than P. gingivalis LPS after the 4th and 10th injections. and of IL-1beta after the 4th, 7th, 10th, 13th, 16th and 20th injections. These results suggest that A. actinomycetemcomitans LPS is a more potent inducer of bone resorption and synthesis of IL-1alpha and IL-1beta in the short term than P. gingivalis LPS.     

MMPs, IL-1, and TNF are regulated by IL-17 in periodontitis

Periodontitis is characterized by periodontal tissue destruction. Since interleukin-17 (IL-17) has been reported to up-regulate IL-1beta and tumor necrosis factor-alpha (TNF-alpha), it was hypothesized that it is increased in periodontitis and up-regulates these cytokines and tissue-destructive matrix metalloproteinases (MMP) in local migrant and resident cells. Immunocytochemistry disclosed elevated IL-1beta, TNF-alpha, and IL-17 levels in periodontitis. These cytokines induced proMMP-1 and especially MMP-3 in gingival fibroblasts, whereas MMP-8 and MMP-9 were not induced. IL-17 was less potent as a direct MMP inducer than IL-1beta and TNF-alpha, but it induced IL-1beta and TNF-alpha production from macrophages, and IL-6 and IL-8 from gingival fibroblasts. In accordance with these findings, immunocytochemistry disclosed that MMP-1 and MMP-3 were increased in periodontitis. Gingival fibroblasts may play an important role in tissue destruction in periodontitis via cytokine-inducible MMP-1 and MMP-3 production, in which IL-17 plays a role as a key regulatory cytokine.     

Interleukin-1beta,clinical parameters and matched cellular-histopathologic changes of biopsied gingival tissue from periodontitis patients

OBJECTIVE: The aim of the present study was to investigate whether interleukin (IL)-1beta in diseased tissues adjacent to periodontal pockets can reflect the degree of inflammation and destruction of these tissues pathologically. BACKGROUND: IL-1beta-dependent mechanisms have been strongly implicated in contributing to inflammation and destruction of bone and attachment loss, which are characteristic features of periodontal disease. This biochemical mediator released during pro-inflammatory processes has not been objectively integrated with clinical and histopathologic features of periodontal disease. METHODS: Periodontitis-affected inflamed tissue and clinically nonaffected healthy gingivae were harvested from 14 periodontal patients, respectively. The severity of tissue inflammation was illustrated by clinical parameters and cellular histologic changes and quantified by histometric assessments. IL-1beta in these extracted specimens was measured with an enzyme-linked immunosorbent assay (ELISA) technique. Pathogenic roles that IL-1beta plays in gingival inflammation and pathologic tissue changes in tissue sections were analyzed statistically. RESULTS: The overall total tissue IL-1beta, tissue concentration of IL-1beta, and percentage of inflammatory cell infiltration (PICI) determined from diseased gingivae were obviously higher than those of controls from both healthy sites of periodontitis and non-periodontitis subjects. With increasing gingival index (GI), plaque index (PlI), and probing depth (PD), there was a marked elevation in total tissue IL-1beta. Total tissue IL-1beta was significantly correlated with GI, PlI, the PICI, and tissue alterations. Polymorphonuclear leukocytes (PMNs) and monocyte-macrophage cells seemed to predominate in heavily infiltrated areas of diseased gingiva. These cell types were confirmed by immunocytochemical localization with either monoclonal mouse antihuman neutrophil elastase antibody or monoclonal mouse antihuman macrophage (CD68) antibody, respectively. Total tissue IL-1beta and the PICI were also elevated in diseased gingivae near deeper PD, while neither total IL-1beta nor tissue concentration was statistically correlated with PD. Thus, correlation analysis indicates that IL-1beta level in inflamed periodontal tissues correlates highly with clinical parameters (GI and PlI) and PICI (the degree of inflammation). CONCLUSIONS: These observations suggest that IL-1beta plays a significant role in the pathogenic mechanisms of periodontal tissue destruction, and that measurement of tissue IL-1beta would be a valuable aid and useful for diagnostic markers of periodontal diseases.     

Production of macrophage inflammatory protein (MIP)-1alpha and MIP-1beta by human polymorphonuclear neutrophils stimulated with Porphyromonas endodontalis lipopolysaccharide

This study was undertaken to investigate the capacity of polymorphonuclear neutrophils (PMNs) to secrete Macrophage Inflammatory Protein (MIP)-1alpha and MIP-1beta after stimulation with Porphyromonas endodontalis lipopolysaccharide (LPS). Escherichia coli LPS was used as a positive control. Venous blood was collected and PMNs were isolated from healthy volunteers. Cells were cultured with various concentrations of LPS for different periods of time. Cell supernatants were assayed by enzyme-linked immunosorbent assay. The levels of chemokine secretion in PMNs stimulated with each LPS were found to be significantly higher than in the unstimulated control cells (p < 0.05), and this expression occurred in a time- and dose-dependent manner. E. coli LPS induced higher levels of cytokines than P. endodontalis LPS. These findings demonstrated that P. endodontalis LPS is capable of stimulating PMNs to produce chemotactic cytokines and suggested that PMNs stimulated with P. endodontalis LPS may play a crucial role in the inflammatory and immunopathological reactions of pulpal and periapical diseases.     

Expression of ICAM-1/LFA-1 in the pocket area of adult periodontitis]

OBJECTIVE: To study the expression of ICAM-1/LFA-1 in the pocket area of adult periodontitis. METHODS: Expressions of ICAM-1/LFA-1 in adult gingival of periodontitis and healthy subjects were studied by alkaline phosphorylase-antialkaline phosphorylase technique. RESULTS: Junctional epithelium and apical part of sulcus epithelium expressed ICAM-1 in both adult periodontitis and healthy gingiva, showing an ICAM-1 gradient change with maximal staining at tooth aspect and weaker staining in the basal layer of keratinocytes. Significantly more LFA-1 positive leukocytes were observed in connective tissues and within pocket epithelium in adult periodontitis than those in healthy gingiva. CONCLUSION: ICAM-1/LFA-1 may provide important adhesion pathway for leukocytes migration into gingiva sulcus in adult periodontitis lesions.