Elevated oral and systemic levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) in periodontitis

The Triggering Receptor Expressed on Myeloid cells 1 (TREM-1) is a cell-surface receptor of the immunoglobulin superfamily, involved in the propagation of the inflammatory response to bacterial challenge. Soluble (s)TREM-1 is released from the cell surface during the course of infection and is a useful inflammatory biomarker in the early diagnosis of systemic sepsis. The hypothesis of this study was that oral and systemic levels of sTREM-1 are elevated in periodontitis. Therefore, the aim was to investigate, by ELISA, the sTREM-1 concentrations in saliva and serum of individuals without periodontitis (control) and persons with chronic or generalized aggressive periodontitis. In saliva, sTREM-1 concentrations were higher in chronic and aggressive periodontitis than in the control group, by 3.3-fold and 5.6-fold, respectively. In serum, these differences were 1.7-fold and 2-fold, respectively. However, there were no significant differences between the two forms of periodontitis, neither in saliva nor in serum. Salivary and serum sTREM-1 levels positively correlated with full-mouth clinical periodontal parameters. In conclusion, the increased oral and systemic levels of sTREM-1 in periodontitis denote a value for this molecule as a biomarker for the disease and may also have implications in the association between periodontal infections and systemic inflammatory response.

Expression and regulation of the NALP3 inflammasome complex in periodontal diseases

Periodontitis is an infectious process characterized by inflammation affecting the supporting structures of the teeth. Porphyromonas gingivalis is a major oral bacterial species implicated in the pathogenesis of periodontitis. Processing of interleukin (IL)-1 family cytokines is regulated by an intracellular innate immune response system, known as the NALP3 [nacht domain-, leucine-rich repeat-, and pyrin domain (PYD)-containing protein 3] inflammasome complex. The aim of the present study was to investigate by quantitative real-time polymerase chain reaction (PCR) the mRNA expression of NALP3, its effector molecule apoptosis associated speck-like protein (ASC), its putative antagonist NLRP2 (NLR family, PYD-containing protein 2), IL-1beta and IL-18 (i) in gingival tissues from patients with gingivitis (n = 10), chronic periodontitis (n = 18), generalized aggressive periodontitis (n = 20), as well as in healthy subjects (n = 20), (ii) in vitro in a human monocytic cell line (Mono-Mac-6), in response to P. gingivalis challenge for 6 h. The clinical data indicate that NALP3 and NLRP2, but not ASC, are expressed at significantly higher levels in the three forms of inflammatory periodontal disease compared to health. Furthermore, a positive correlation was revealed between NALP3 and IL-1beta or IL-18 expression levels in these tissues. The in vitro data demonstrate that P. gingivalis deregulates the NALP3 inflammasome complex in Mono-Mac-6 cells by enhancing NALP3 and down-regulating NLRP2 and ASC expression. In conclusion, this study reveals a role for the NALP3 inflammasome complex in inflammatory periodontal disease, and provides a mechanistic insight to the host immune responses involved in the pathogenesis of the disease by demonstrating the modulation of this cytokine-signalling pathway by bacterial challenge.

Tumor Necrosis Factor-α-converting Enzyme (TACE) Levels in Periodontal Diseases

Tumor necrosis factor-α-converting enzyme (TACE) is a metalloprotease which can shed several cytokines from the cell membrane, including receptor activator of NF-κB ligand (RANKL). This study aimed to investigate the hypothesis that TACE would be elevated in the gingival crevicular fluid (GCF) of persons with periodontitis. Total TACE amounts in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis or in healthy persons. TACE concentrations in GCF were higher in persons with chronic and aggressive periodontitis than in those with gingivitis, although not significantly higher than in healthy persons. Persons with chronic periodontitis receiving immunosuppressive treatment exhibited over 10-fold lower TACE levels than the other periodontitis groups. TACE was positively correlated with probing pocket depth, clinical attachment levels, and RANKL concentrations in GCF. In conclusion, the increased GCF TACE levels in persons with periodontitis and their positive correlation with RANKL may indicate an association of this enzyme with alveolar bone loss, and may warrant special attention in future therapeutic approaches.

Differential expression of receptor activator of nuclear factor-?B ligand and osteoprotegerin mRNA in periodontal diseases

BACKGROUND AND OBJECTIVE

Receptor activator of nuclear factor-kappaB ligand (RANKL) is responsible for the induction of osteoclastogenesis and bone resorption, whereas its decoy receptor, osteoprotegerin, can directly block this action. Because this dyad of cytokines is crucial for regulating the bone remodelling process, imbalances in their expression may cause a switch from the physiological state to enhanced bone resorption or formation. This study investigated the mRNA expression of RANKL and osteoprotegerin, as well as their relative ratio, in the gingival tissues of patients with various forms of periodontal diseases.

MATERIAL AND METHODS

Gingival tissue was obtained from nine healthy subjects and 41 patients, who had gingivitis, chronic periodontitis, generalized aggressive periodontitis, and chronic periodontitis and were receiving immunosuppressant therapy. Quantitative real-time polymerase chain reaction was employed to evaluate the mRNA expression of RANKL and osteoprotegerin in these tissues.

RESULTS

Compared with healthy individuals, patients in all periodontitis groups, but not those with gingivitis, exhibited stronger RANKL expression and a higher relative RANKL/osteoprotegerin ratio. In addition, osteoprotegerin expression was weaker in patients with chronic periodontitis. When patients with generalized aggressive periodontitis and chronic periodontitis were compared, the former exhibited stronger RANKL expression, whereas the latter exhibited weaker osteoprotegerin expression, and there was no difference in their relative ratio. When chronic periodontitis patients were compared with chronic periodontitis patients receiving immunosuppressant therapy, osteoprotegerin, but not RANKL, expression was stronger in the latter.

CONCLUSION

This study demonstrates that RANKL and osteoprotegerin expression are differentially regulated in various forms of periodontitis, and the relative RANKL/osteoprotegerin ratio appears to be indicative of disease occurrence. This information may confer diagnostic and therapeutic value in periodontitis.

Adjunctive low-dose doxycycline therapy effect on clinical parameters and gingival crevicular fluid tissue plasminogen activator levels in chronic periodontitis

OBJECTIVE AND DESIGN

The present study examined effectiveness of low-dose doxycycline (LDD) in combination with nonsurgical therapy on gingival crevicular fluid (GCF) tissue plasminogen activator (t-PA) levels and clinical parameters in chronic periodontitis (CP) a over 12-month period.

METHODS

GCF samples were collected, probing depth (PD), clinical attachment level (CAL), gingival index (GI) and plaque index were recorded at baseline, 3, 6, 9 and 12 months. CP patients (n = 65) were randomized to LDD or placebo groups. LDD group received LDD (20 mg) b.i.d for 3-months plus and root planing (SRP), while placebo group was given placebo capsules b.i.d for 3-months plus SRP. GCF t-PA levels were determined by ELISA. Friedman, Wilcoxon and Mann-Whitney test was used for statistical analysis.

RESULTS

Significant improvement was observed in all clinical parameters in both groups over 12-month period (p < 0.01). LDD group had lower PD, CAL and GI scores than placebo group at 6, 9 and 12-months (p < 0.05). GCF t-PA levels reduced in both groups over 12-month period (p < 0.01). LDD group had lower GCF t-PA levels than placebo group at 6 and 9-months (p < 0.05).

CONCLUSIONS

These results provide additional information about usefulness of LDD therapy as an adjunct to nonsurgical therapy in long-term management of periodontitis.

Epithelial and connective tissue cell CTGF/CCN2 expression in gingival fibrosis

Gingival overgrowth is a side effect of certain medications and occurs in non-drug-induced forms either as inherited (human gingival fibromatosis) or idiopathic gingival overgrowth. The most fibrotic drug-induced lesions develop in response to therapy with phenytoin; the least fibrotic lesions are caused by cyclosporin A; and intermediate fibrosis occurs in nifedipine-induced gingival overgrowth. Connective tissue growth factor (CTGF/CCN2) expression is positively related to the degree of fibrosis in these tissues. The present study has investigated the hypothesis that CTGF/CCN2 is expressed in human gingival fibromatosis tissues and contributes to this form of non-drug-induced gingival overgrowth. Histopathology/immunohistochemistry studies showed that human gingival fibromatosis lesions are highly fibrotic, similar to phenytoin-induced lesions. Connective tissue CTGF/CCN2 levels were equivalent to the expression in phenytoin-induced gingival overgrowth. The additional novel observation was made that CTGF/CCN2 is highly expressed in the epithelium of fibrotic gingival tissues. This finding was confirmed by in situ hybridization. Real-time polymerase chain reaction (PCR) analyses of RNA extracted from drug-induced gingival overgrowth tissues for CTGF/CCN2 were fully consistent with these findings. Finally, normal primary gingival epithelial cell cultures were analysed for basal and transforming growth factor beta1 (TGF-beta1) or lysophosphatidic acid-stimulated CTGF/CCN2 expression at protein and RNA levels. These data indicate that fibrotic human gingival tissues express CTGF/CCN2 in both the epithelium and connective tissues; that cultured gingival epithelial cells express CTGF/CCN2; and that lysophosphatidic acid further stimulates CTGF/CCN2 expression. These findings suggest that interactions between epithelial and connective tissues could contribute to gingival fibrosis.

Phenotypic and functional analysis of peripheral blood mononuclear cells in generalised aggressive and chronic periodontitis patients

BACKGROUND

The aetiology and pathogenesis of periodontal disease may involve dysfunctions in the cellular immune responses. The aim of the present study was to study the phenotypic and functional activities of peripheral blood mononuclear cells (PBMC) from 16 patients with generalised aggressive periodontitis (G-AP), 13 patients with chronic periodontitis (CP) and 20 periodontally healthy subjects (H).

METHODS

The relative counts of CD3+, CD4+, CD8+ T cells, T cells exhibiting HLA DR antigen and interleukin-2 receptor, CD19+ B cells and natural killer cells were determined by two colour flow cytometry using monoclonal antibodies. Blastogenic response of PBMC to mitogen phytohemagglutinin (PHA) was assessed after 96 h incubation by measuring 3(H)-thymidine incorporation and the results were expressed as net counts per minute. Spontaneous PBMC proliferation was also evaluated in unstimulated culture and the results were reported as mean counts per minute. Comparisons of G-AP, CP and H groups were performed using the Kruskal-Wallis and Bonferroni-corrected Mann-Whitney U test.

RESULTS

No significant differences in the relative counts of PBMC subsets were found between G-AP, CP and H groups (P > 0.05) with the exception of lower relative amount of CD3+ T cells found in the CP group compared with healthy subjects (P = 0.0048). Blastogenic response to PHA was significantly suppressed in G-AP and CP groups relative to that of H group (P < 0.02). However, there was no significant difference in the blastogenic response to PHA between G-AP and CP groups (P > 0.05). Spontaneous proliferative response of G-AP and CP groups was also significantly lower compared to that of H group (P < 0.02). Similarly, no significant difference in spontaneous PBMC response was observed between G-AP and CP groups (P > 0.05).

CONCLUSIONS

Although G-AP and CP patients have similar amount of immune cells compared to healthy subjects, reduced functional activities of these cells may suggest the existence of defective cellular immune mechanism for the susceptibility to periodontal disease. One has to keep in mind that periodontal diseases have a genetic basis and the present functional analysis might not be connected to the actual genetic predisposition to the disease.

Localized aggressive periodontitis in a patient with type 1 diabetes mellitus: a case report

BACKGROUND

Poor metabolic control of diabetes mellitus (DM) has often been associated with the severity of periodontal disease. The aim of this report is to present a 9-year-old female with localized aggressive periodontitis who had a history of type 1 DM and the outcome of her treatment.

METHODS

The patient had received medical, clinical, and radiographic periodontal examinations. Peripheral blood analysis was done as well. She had non-surgical periodontal treatment, and medical management of her diabetes was performed at the same time. She was followed longitudinally for 5 years.

RESULTS

Medical examination revealed no pathological findings except for growth retardation. Laboratory tests showed that she had poor metabolic control, with 497 mg/dl fasting blood glucose and 15.6% HbA1c. The random migration and neutrophil chemotaxis were significantly reduced. Periodontal treatment and metabolic control of her diabetes resulted in significant improvement in her periodontal condition. No incipient periodontal breakdown was observed around the teeth after 5 years from baseline.

CONCLUSIONS

This report proves the efficiency of periodontal therapy in the prevention of future periodontal breakdown in a systemically compromised patient. It seems that in certain individuals who are predisposed to the aggressive forms of periodontitis, clinical and medical examinations and intervention to the systemic condition, in combination with periodontal treatment, are important in the management of these individuals.

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.

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.

Matrix metalloproteinases (MMP-8 and -9) and neutrophil elastase in gingival crevicular fluid of cyclosporin-treated patients

BACKGROUND

Gingival overgrowth (GO) is one of the most important side effects of cyclosporin A (CsA) medication, but its pathogenesis is not completely understood. The aim of this study was to identify and compare collagenase-2 (MMP-8), gelatinase-B (MMP-9), and neutrophil (PMN)-elastase levels in gingival crevicular fluid (GCF) from 15 renal transplant patients receiving CsA therapy and exhibiting CsA GO, 14 patients with gingivitis, and 10 periodontally healthy subjects.

METHODS

Clinical data were obtained on plaque index, papilla bleeding index, and hyperplastic index from each site studied. GCF samples and clinical data were collected 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. CsA GO+ and CsA GO- sites were divided into 2 subgroups as clinically not inflamed (PBI = 0) and inflamed (PBI > or =1). GCF MMP-8, MMP-9, and PMN-elastase levels were analyzed by immunofluorometric assay.

RESULTS

GCF MMP-8 and -9 levels and clinical degrees of gingival inflammation in CsA GO+ sites were similar to those in diseased sites. However, GCF elastase levels were significantly lower in CsA GO+ sites compared to those in diseased sites. GCF MMP-8, -9 and PMN-elastase levels were not different between CsA GO- sites and healthy sites. Additionally, GCF MMP-8 and -9 levels in inflamed CsA GO+ sites were higher but not statistically significantly than those in diseased sites. In contrast, GCF PMN-elastase levels in inflamed CsA GO+ sites were significantly lower than the levels in diseased sites.

CONCLUSIONS

These results show that CsA therapy does not have a significant effect on GCF MMP-8 and MMP-9 levels, but the gingival inflammation seems to be the main reason for their elevations. However, low GCF PMN-elastase levels can be an important factor in the pathogenesis of CsA-induced gingival overgrowth. CsA therapy does not eliminate the potential use of GCF MMP-8 and -9 as future diagnostic markers of gingival inflammation.

Association between periodontal disease and acute myocardial infarction

BACKGROUND

Coronary heart disease is the leading cause of morbidity and mortality throughout the world. Well-known risk factors independently or combined participate in both myocardial infarction and atherosclerosis. Recent data have shown that viral and bacterial infections may also contribute to the acute thromboembolic events. The aim of the present study was to investigate the possible association between periodontal health and coronary heart disease in patients with acute myocardial infarction and chronic coronary heart disease.

METHODS

A total of 120 patients, 60 with acute myocardial infarction (AMI) and 60 with chronic coronary heart disease (CCHD) were included in this study. The patients in the AMI group (50 men and 10 women; mean age 53.8 +/- 9.5 years) were admitted to the Department of Cardiology, University Hospital of Ege because of AMI. The CCHD patients group (42 men and 18 women; mean age 58.5 +/- 11.6 years) had no documented history of recent acute coronary events. All patients were clinically examined and completed a medical questionnaire. Missing teeth, restorations, probing depth (PD) and bleeding on probing (BOP) were recorded. Blood samples were taken on admission for measurements of serum total cholesterol, triglycerides, high density lipoprotein cholesterol (HDL-cholesterol), low density lipoprotein cholesterol (LDL-cholesterol), and fasting blood glucose level. Sample proportions were compared by chi square test, quantitative variables with Student t test. The relation of clinical parameters and conventional risk factors to AMI was assessed with logistic regression analysis.

RESULTS

The number of sites with PD > or = 4 mm, the percentage of sites exhibiting BOP, smoking status, total cholesterol, LDL-cholesterol, and triglycerides were statistically different between AMI and CCHD groups (P <0.05). Logistic regression analysis showed that the percentage of sites exhibiting BOP, the number of sites with PD > or = 4, the number of restorations, smoking status, and triglycerides levels were significantly associated with AMI (P <0.05).

CONCLUSIONS

The results of this study indicate that periodontal disease may be associated with acute myocardial infarction. To our knowledge, this is the first study that reports the importance of periodontal health in the occurrence of acute myocardial infarction in a Turkish population. We propose that prospective randomized studies are needed to determine whether periodontal disease is a risk factor in the occurrence of acute myocardial infarction.

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.