Distinct roles for interleukin-12p40 and tumour necrosis factor in resistance to oral candidiasis defined by gene-targeting

Cell-mediated immunity is important for anti-Candida host defence in mucosal tissues. In this study we used cytokine-specific gene knockout mice to investigate the requirement for T helper type 1 (Th1) and Th2 cytokines in recovery from oral candidiasis. Knockout mice used in this study included interleukin-4 (IL-4), IL-10, IL-12p40, interferon-gamma (IFN-gamma), and tumour necrosis factor (TNF). The mice were challenged either orally or systemically with Candida albicans yeasts, and levels of colonization were determined. IL-12p40 knockout mice developed chronic oropharyngeal candidiasis, but were not more susceptible to systemic challenge. On the other hand, TNF knockout mice displayed increased susceptibility to both oral and systemic challenge, but only in the acute stages of infection. TNF apparently has a protective effect in the acute stages of both oral and systemic candidiasis, whereas IL-12p40 is essential for recovery from oral but not systemic candidiasis. The role of IL-12p40, and its relation to T-cell-mediated responses remain to be determined.     

The role of cytokines in a Porphyromonas gingivalis‐induced murine abscess model

Introduction: Porphyromonas gingivalis is an important periodontopathic bacterium that is strongly associated with periodontal disease and is part of human dental plaque. Periodontal disease results from the interaction of the host with bacterial products, and T‐cell‐derived cytokines remain critical in the immunoregulation of periodontal disease. Methods: The aim of this study was to examine the role of T helper type 1 [interleukin‐12p40 (IL‐12p40), interferon‐γ, tumour necrosis factor (TNF)] and type 2 (IL‐4, IL‐10) cytokines in the immune response to a subcutaneous challenge with P. gingivalis using a well‐established murine abscess model, in genetically modified cytokine‐specific knockout mice. Results: IL‐12p40^−/− mice exhibited more advanced tissue destruction and a reduced inflammatory cell infiltrate after subcutaneous P. gingivalis challenge. Deficiency of IL‐4 or IL‐10 did not result in increased susceptibility to P. gingivalis‐mediated tissue destruction. Furthermore, TNF deficiency appeared to reduce local tissue destruction. Interestingly, serum‐specific antibodies suggested a strong T helper type 2 response. Conclusion: The results of our study indicate an important role for IL‐12 in a primary P. gingivalis subcutaneous challenge.     

Interleukin‐1 β, interleukin‐12 and interleukin‐18 levels in gingival fluid and serum of patients with gingivitis and periodontitis

Introduction: Cytokines are of major importance in periodontal disease progression. Interleukin‐12 (IL‐12) stimulates interferon‐γ production by T helper type 1 (Th1) cells while IL‐18 induces Th1 responses when present with IL‐12 but Th2 responses in the absence of IL‐12. IL‐1β has been correlated with periodontal disease destruction. This study determined the local concentrations of these cytokines in sites of gingivitis and periodontitis. Methods: Gingival crevicular fluid was collected from two sites in each of 10 gingivitis patients and from two gingivitis sites and two periodontitis sites from each of 10 periodontitis patients. Serum samples were also collected. IL‐1β, biologically active IL‐12 p70, the IL‐12 p40 subunit and IL‐18 concentrations were determined by enzyme‐linked immunoabsorbent assay. Results: IL‐1β and IL‐18 concentrations were higher in the gingival crevicular fluid from periodontitis patients than in that from gingivitis patients; IL‐18 concentrations were higher than those of IL‐1β. Very little IL‐12, either p40 or p70, was detected in the gingival crevicular fluid samples. In the serum, very low levels of cytokines were found. The level of serum IL‐12 p40, however, was higher than in the fluid from periodontitis sites of periodontitis patients. Conclusion: The local production of IL‐1β and IL‐18 in the gingival crevicular fluid increased with increasing inflammation and IL‐18 was the predominant cytokine at both gingivitis and periodontitis sites. Very little IL‐12 was detected with levels decreasing with increasing inflammation. These results suggest that there is an association between severity of periodontal disease and levels of IL‐1, IL‐12 and IL‐18.     

Role of MyD88‐dependent and MyD88‐independent signaling in Porphyromonas gingivalis‐elicited macrophage foam cell formation

Clinical studies and experimental modeling identify a potential link between periodontal disease and periodontal pathogens such as Porphyromonas gingivalis and atherosclerosis and formation of macrophage foam cells. Toll‐like receptors and molecules governing their intracellular signaling pathways such as MyD88 play roles in atherosclerosis, as well as host response to P. gingivalis. The aim of this study was to define roles of MyD88 and TRIF during macrophage foam cell formation in response to P. gingivalis. In the presence of human low‐density lipoprotein (LDL) mouse bone‐marrow‐derived macrophages (BMφ) cultured with P. gingivalis responded with significant reduction in tumor necrosis factor‐α (TNF‐α) and interleukin‐6 (IL‐6). The BMφ stained strongly with oil red O, regardless of whether bacterial challenge occurred concurrent with or before LDL treatment. Heat‐killed P. gingivalis stimulated foam cell formation in a similar way to live bacteria. The BMφ from MyD88‐knockout and Lps2 mice revealed a significant role for MyD88, and a minor role for TRIF in P. gingivalis‐elicited foam cell formation. Porphyromonas gingivalis‐elicited TNF‐α and IL‐6 were affected by MyD88 ablation and to a lesser extent by TRIF status. These data indicate that LDL affects the TNF‐α and IL‐6 response of macrophages to P. gingivalis challenge and that MyD88 and TRIF play important roles in P. gingivalis‐elicited foam cell formation.     

Assessment of the involvement of the macrophage migration inhibitory factor–glucocorticoid regulatory dyad in the expression of matrix metalloproteinase‐2 during periodontitis

Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine and counter‐regulator of endogenous glucocorticoids (GCs). It is implicated in acute and chronic inflammatory diseases. This study investigated the role of the MIF–GC regulatory dyad in the expression and release of matrix metalloproteinase‐2 (MMP‐2) during periodontitis, in vivo and in vitro. In a Mif‐knockout (KO) mouse model of ligature‐induced periodontitis, gingival tissues and blood were collected and analysed for levels of interleukin‐6 (IL‐6), MIF, MMP‐2, and corticosterone. In addition, human gingival fibroblasts (HGFs) were tested for production of IL‐6 and MMP‐2 after stimulation with hydrocortisone (HC), MIF, tumour necrosis factor‐alpha (TNF‐α), or Fusobacterium nucleatum, a pathogen known to elicit immune responses during periodontitis. Wild‐type (WT) mice showed a local and systemic increase of MIF levels during inflammation, which was confirmed by increased local IL‐6 concentrations. Systemic GC levels were reduced in WT and Mif‐KO mice during inflammation, with overall lower concentrations in Mif‐KO mice. In vivo and in vitro, MMP‐2 production was not dependent on MIF or inflammatory stimuli, but was inhibited by HC. Therefore, MIF does not appear to stimulate expression of MMP‐2 in the gingival tissues, whereas GC upregulates MIF and downregulates MMP‐2. Our findings further suggest that MIF may regulate systemic GC levels.     

Irradiation‐induced oral candidiasis in an experimental murine model

The aim of this experiment was to establish a mouse model of irradiation‐induced oral candidiasis and to explore the cellular populations and mechanisms by which the infection is cleared from the oral mucosa. BALB/c mice received irradiation to the head and neck equivalent to 800 Rad using a Cobalt 60 gamma source. Both irradiated and non‐irradiated mice were infected orally with 1×10⁸Candida albicans yeasts. Compared with untreated controls, irradiated animals developed a more severe infection of longer duration, with hyphae penetrating the oral mucosa. Monoclonal antibody depletion of CD4⁺ but not CD8⁺ T cells from the systemic circulation prolonged the infection in irradiated mice, but not in controls. Supernatants of submandibular and superficial cervical lymph node cultures from irradiated animals demonstrated significantly higher titers of interleukin‐12, but similar levels of interferon‐γ compared with controls. Screening for cytokine production by an RNase protection assay detected only macrophage migration inhibition factor in irradiated and non‐irradiated oral tissues from day 8 onwards. The results of this study demonstrate a requirement for CD4⁺ T cells in the recovery from oral candidiasis induced by head and neck irradiation in mice, and are consistent with a role for Th₁‐type cytokines in host resistance.     

Salivary cytokine profiles in the immunocompetent individual with Candida‐associated denture stomatitis

Cell‐mediated immunity conferred by CD4⁺ T helper cells is considered the predominant host defense against mucosal Candida infections, with Thelper (Th1)‐type responses associated with resistance to infection and Th2‐type responses associated with susceptibility to infection. Oropharyngeal candidiasis, the most common oral opportunistic infection in HIV‐infected persons, is associated with a Th2‐type cytokine profile in saliva. To obtain more direct evidence for a role of salivary cytokines in susceptibility to oropharyngeal candidiasis during immunosuppression, we evaluated Th1/Th2‐type cytokines in the saliva of those with denture stomatitis, a form of oropharyngeal candidiasis not related to immunosuppression. Results showed that HIV‐negative denture wearers with and without denture stomatitis demonstrated a mixed Th1/Th2 cytokine profile with no significant differences found between the groups. These results suggest that a local Th cytokine dichotomy in saliva is not associated with susceptibility to denture stomatitis in immunocompetent persons.     

Effect of Curcumin on Systemic T Helper 17 Cell Response; Gingival Expressions of Interleukin‐17 and Retinoic Acid Receptor‐Related Orphan Receptor γt; and Alveolar Bone Loss in Experimental Periodontitis

Background: Curcumin has anti‐inflammatory and antioxidant effects and is reported to have many biologic activities. The current study examines effect of curcumin on: 1) systemic T helper 17 (Th17) cell response; 2) gingival expressions of interleukin (IL)‐17 and retinoic acid receptor‐related orphan receptor (ROR) γt; and 3) alveolar bone loss (ABL) in experimental periodontitis. Methods: Thirty‐eight male albino Wistar rats were divided into four groups: 1) group 1 = periodontitis; 2) group 2 = periodontitis with curcumin treatment; 3) group 3 = periodontally healthy with curcumin treatment; and 4) group 4 = periodontally healthy. Curcumin was administered via oral gavage (30 mg/kg/d) for 15 days. After sacrifice via exsanguination, the following serum levels were determined using enzyme‐linked immunosorbent assay: 1) IL‐1β; 2) IL‐6; 3) IL‐17A; 4) IL‐23; and 5) transforming growth factor‐ β. Morphometric evaluation of ABL was conducted and expression levels of IL‐17 and RORγt in gingival tissues were evaluated immunohistochemically. Results: Group 2 had significantly lower ABL than group 1 (P <0.0125). Highest expression levels of IL‐17 and RORγt were observed in group 1 and were significantly higher than those in all other groups (P <0.0125). The only serum biochemical parameter significantly different among groups was level of IL‐23 (P <0.05). Serum IL‐23 levels were higher in groups 1 and 2 than groups 3 and 4 (P <0.0125); however, they were not significantly different for groups 1 and 2 (P >0.0125). Conclusion: Curcumin seems to be a promising host modulatory agent in periodontal disease pathogenesis regarding IL‐17/IL‐23 axis, with a decreasing effect on ABL and gingival expressions of IL‐17 and RORγt.     

Expression of CD163, interleukin‐10, and interferon‐gamma in oral squamous cell carcinoma: mutual relationships and prognostic implications

Tumor‐associated macrophages (TAMs) and their associated inflammatory cytokines represent the major inflammatory component of the stroma of many tumors and can affect prognosis in the case of neoplasms. The objective of this study was to determine the prognostic significance of CD163⁺ cells, interleukin‐10 (IL‐10), and interferon‐gamma (IFN‐γ) in oral lesions associated with oral squamous cell carcinoma (OSCC). The levels of CD163, IFN‐γ, and IL‐10 in the tissue samples of 240 patients with OSCC and 58 patients with other oral lesions were assessed by immunohistochemistry. Individuals with low IFN‐γ levels, high IL‐10 levels, and low CD163 levels were of special concern with respect to OSCC progression. We found that high levels of CD163, or a combination of low IFN‐γ levels, high IL‐10 levels, and low CD163 levels, were associated with poorer overall survival (OS). CD163⁺ cells provide better predictive power for OS in comparison with traditional markers, such as clinical stage and lymph node metastasis. Therefore, CD163⁺ cells may be effective prognostic predictors of OSCC. IL‐10 may also indicate poor outcomes when IFN‐γ secretion is low and the cells are CD163^?.     

Deficiency of iNOS contributes to Porphyromonas gingivalis‐induced tissue damage

Periodontitis is a chronic inflammatory disease that results in extensive soft and hard tissue destruction of the periodontium. Porphyromonas gingivalis possesses an array of virulence factors and has been shown to induce expression of inducible nitric oxide synthase (iNOS) in inflammatory cells. The aim of this study was to investigate the effect of eliminating iNOS in a murine model of P. gingivalis infection. This was achieved by utilizing a P. gingivalis‐induced skin abscess model, and an alveolar bone loss model employing an oral infection of P. gingivalis in iNOS knockout mice. The results indicated that iNOS knockout mice exhibit more extensive soft tissue damage and alveolar bone loss in response to P. gingivalis infection compared to wild‐type mice. The local immune response to P. gingivalis in iNOS knockout mice was characterized by increased numbers of polymorphonuclear monocytes, while the systemic immune response was characterized by high levels of interleukin‐12. The iNOS is required for an appropriate response to P. gingivalis infection.     

In vivo photodynamic inactivation of Candida albicans using chloro‐aluminum phthalocyanine

This study evaluated the photoinactivation of Candida albicans in a murine model of oral candidiasis using chloro‐aluminum phthalocyanine (ClAlP) encapsulated in cationic nanoemulsions (NE) and chloro‐aluminum phthalocyanine (ClAlP) diluted in DMSO (DMSO) as photosensitizer (PS). Seventy‐five 6‐week‐old female Swiss mice were immunosuppressed and inoculated with C. albicans to induce oral candidiasis. PDT was performed on the tongue by the application of the photosensitizers and LED light (100 J cm^?2–660 nm). Twenty‐four hours and 7 days after treatments, microbiological evaluation was carried out by recovering C. albicans from the tongue of animals (CFU ml^?1). Then, mice were sacrificed and the tongues were surgically removed for histological and biomolecular analysis of pro‐ and anti‐inflammatory cytokines. Data were analyzed by ANOVA followed by Tukey's post hoc test. ClAlP‐NE‐mediated PDT reduced 2.26 log₁₀ of C. albicans recovered from the tongue when compared with the control group (P?L?) (P < 0.05). PDT did not promote adverse effects on the tongue tissue. Seven days after treatment, all animals were completely healthy. In summary, PDT mediated by chloro‐aluminum phthalocyanine entrapped in cationic nanoemulsions was effective in reducing C. albicans recovered from the oral lesions of immunocompromised mice.     

Increased Expression of Interleukin (IL)‐35 and IL‐17, But Not IL‐27, in Gingival Tissues With Chronic Periodontitis

Background: Interleukin (IL)‐35 plays an important role in immune regulation through the suppression of effector T‐cell populations, including T‐helper 17 (Th17) cells. Although Th17 cells and IL‐17 are involved in the pathogenesis of periodontitis, the level of IL‐35 in inflamed periodontal tissues is unclear. Here, IL‐35, IL‐17, and IL‐27 production/expression in gingival crevicular fluid (GCF) and human gingival tissue were investigated. Methods: GCF samples were collected from buccal (mesial, center, and distal) sites of teeth from patients with chronic periodontitis (CP) and healthy controls and were analyzed by enzyme‐linked immunosorbent assay for IL‐35 (periodontitis, n = 36; healthy, n = 30) and IL‐17 (periodontitis, n = 16; healthy, n = 13). Gingival tissue, including sulcus/pocket epithelium and underlying connective tissue, was collected from an additional 10 healthy participants and 10 patients with CP and were analyzed by quantitative polymerase chain reaction (qPCR) for Epstein Barr virus‐induced gene 3 (EBI3), IL12A, and IL17A. IL27p28 was also tested by qPCR. Results: IL‐35 and IL‐17 were significantly higher in GCF from patients with periodontitis than healthy participants (P <0.01, P <0.05, respectively). In both healthy participants and those with periodontitis, positive correlations were found among IL‐35 and probing depth and clinical attachment level (CAL) as well as between IL‐17 and CAL. EBI3, IL12A (components of IL‐35), and IL17A messenger RNA expression levels were significantly higher in inflamed gingival tissue than in healthy control tissues (P <0.05). IL27p28 was not detected in any sample, suggesting that IL‐27 is not produced in large quantities in periodontal tissue. Conclusion: IL‐35 and IL‐17, but not IL‐27, may play important roles in the pathogenesis of periodontitis.     

A Sialidase‐Deficient Porphyromonas gingivalis Mutant Strain Induces Less Interleukin‐1β and Tumor Necrosis Factor‐α in Epi4 Cells Than W83 Strain Through Regulation of c‐Jun N‐Terminal Kinase Pathway

Background: Porphyromonas gingivalis is one of the major periodontal pathogens. In a previous study, a mouse abscess model showed that sialidase deficiency of P. gingivalis weakened its virulence, but the mechanism behind this observation remains unknown. Methods: A sialidase‐deficient mutant strain (△PG0352) and a complemented strain (com△PG0352) were constructed. Epi4 cells were stimulated by wild‐type strain P. gingivalis W83, △PG0352, or com△PG0352. Real‐time polymerase chain reaction was carried out to detect expression of virulent genes in P. gingivalis and interleukin (IL)‐1β, IL‐6, IL‐8, and tumor necrosis factor (TNF)‐α in epi4 cells. Activities of sialidase, gingipains, and lipopolysaccharide (LPS) were compared among the different P. gingivalis strains. Levels of IL‐1β and TNF‐α in the epi4 cells supernatant were detected by enzyme‐linked immunosorbent assay and levels of p38, extracellular signal‐regulated kinase, c‐Jun N‐terminal kinase (JNK), and phospho‐c‐Jun were detected by western blotting. Results: Compared with P. gingivalis W83 and com△PG0352, activities of Kgp and Rgp gingipains and amount of LPS decreased in △PG0352, whereas there were no differences in LPS activity among these three strains. Level of phospho‐JNK was lower in epi4 cells stimulated by △PG0352. △pG0352 induced less IL‐1β and TNF‐α and more IL‐8 in epi4 cells; differences in IL‐1β and TNF‐α could not be detected after JNK blocking. Conclusion: A sialidase‐deficient P. gingivalis mutant strain induces less IL‐1β and TNF‐α in epi4 cells than W83 strain through regulation of JNK pathway.     

Cytokines in healthy temporomandibular joint synovial fluid

Analysis of temporomandibular joint (TMJ) synovial fluid may elucidate the aetiology of temporomandibular disorders and arthritic conditions, as well as the inflammatory mechanisms involved. Knowledge about healthy synovial fluid is necessary to understand TMJ pathologies. We aimed to quantify the proinflammatory cytokines interleukin (IL)‐1β, IL‐2, IL‐6 and tumour necrosis factor (TNF), and the anti‐inflammatory cytokines IL‐10 and interferon (IFN)‐γ in healthy TMJ synovial fluid to serve as reference values for future studies on TMJ pathologies. Twenty healthy, young adult volunteers without temporomandibular dysfunction were included. Bilateral synovial fluid samples were obtained using the push‐pull technique with hydroxocobalamin described by Alstergren in 1999. Cytokines were quantified with Luminex multiplex assays and compared using nonparametric statistical analysis. No serious adverse effects were reported. Of 40 possible samples, 14 fulfilled the strict sampling criteria and were included in the analysis. Cytokine values (reported as medians with interquartile ranges) were as follows: TNF, 23 (13–37) pg mL^?1; IL‐2, 1·8 (0–22) pg mL^?1; and INF‐γ, 10 (0–47) pg mL^?1. IL‐1β, IL‐6 and IL‐10 were almost undetectable. In addition, TNF and INF‐γ cytokine levels correlated. We demonstrated that TNF was consistently detected and IFN‐γ and IL‐2 sporadically detected in the TMJ synovial fluid of healthy individuals using the hydroxocobalamin method and a multiplex assay. The cytokines IL‐10, IL‐1β and IL‐6 were barely detectable in this sample of healthy TMJs.     

Divergence of the systemic immune response following oral infection with distinct strains of Porphyromonas gingivalis

Periodontitis is a polymicrobial oral infection characterized by the destruction of tooth‐supporting structures that can be linked to systemic diseases such as cardiovascular disease, diabetes or rheumatoid arthritis. Porphyromonas gingivalis, a bacterium implicated in the etiology of periodontitis, has shown variation in inducing T‐cell responses among different strains. Therefore, in this study we investigated the strain‐specific immune response using a murine experimental model of periodontitis. Periodontitis was induced by P. gingivalis strains A7A1‐28, W83 and W50, and later confirmed by the presence of P. gingivalis in the oral microflora and by alveolar bone resorption. Splenocytes were evaluated for gene expression, cellular proteins and cytokine expression. Dendritic cells were stimulated in vitro for T helper cell–cytokine profiling. Results showed that P. gingivalis had the ability to alter the systemic immune response after bacterial exposure. Strains W50 and W83 were shown to induce alveolar bone loss, whereas the A7A1‐28 strain did not significantly promote bone resorption in mice. Splenocytes derived from mice infected with strains W50 and W83 induced expression of high levels of interleukin‐4 (IL‐4) but A7A1‐28 stimulated increased IL‐10. Stimulation of dendritic cells in vitro showed a similar pattern of cytokine expression of IL‐12p40, IL‐6 and transforming growth factor‐β among strains. A distinct systemic response in vivo was observed among different strains of P. gingivalis, with IL‐10 associated with the least amount of alveolar bone loss. Evaluation of pathogen‐driven systemic immune responses associated with periodontal disease pathogenesis may assist in defining how periodontitis may impact other diseases.     

Clinical and immunological effects of azithromycin in Behçet''s disease

Background: The aim of this study was to evaluate the effects of azithromycin on mucocutaneous manifestations, oral health and immune response in Behçet's disease (BD). Methods: Eight BD patients with active mucocutaneous symptoms were treated with azithromycin for 4 weeks. Oral health, clinical manifestations and in vitro interleukin (IL)‐12, interferon (IFN)‐γ, IL‐10 and monocyte chemotactic protein (MCP)‐1 responses were evaluated before and after treatment. Results: The number of folliculitic lesions, healing time of oral ulcers and scores of plaque indexes (PLIs) were lower after azithromycin treatment (P < 0.05). Scores of PLIs correlated positively with the healing time of oral ulcers (P = 0.02). Although a trend towards increased stimulated IL‐10 responses with azithromycin was observed, no statistically significant difference was found. Stimulated and unstimulated MCP‐1, IFN‐γ and IL‐12 responses were similar before and after treatment (P > 0.05). Conclusion: Azithromycin was observed to be effective in decreasing folliculitic lesions and fastening the healing time of oral ulcers in BD.     

Significance of elevated gingival crevicular fluid tumor necrosis factor‐α and interleukin‐8 levels in chronic hemodialysis patients with periodontal disease

Da? A, F?rat ET, Kadiro?lu AK, Kale E, Y?lmaz ME. Significance of elevated gingival crevicular fluid tumor necrosis factor‐α and interleukin‐8 levels in chronic hemodialysis patients with periodontal disease. J Periodont Res 2010; 45: 445–450. © 2010 John Wiley & Sons A/S Background and Objective: The prevalence of chronic renal disease in industrialized countries is increasing, and chronic renal disease and periodontitis can have significant, reciprocal effects. The aim of this study was to evaluate the associations between specific clinical parameters and the levels of tumor necrosis factor‐α (TNF‐α) and interleukin‐8 (IL‐8) in the gingival crevicular fluid of hemodialysis (HD) patients with periodontal disease. Material and Methods: Forty‐three HD patients and 43 systemically healthy subjects were enrolled in this study. Plaque index (PI), gingival index (GI) and pocket depth were used to determine periodontal status. Venous blood samples were obtained from each patient in the morning before the dialysis session and analyzed to determine the levels of inflammatory, biochemical and hematological parameters. Gingival crevicular fluid was collected from all subjects, and the levels of TNF‐α and IL‐8 were determined in the gingival crevicular fluid samples. Results: The following results were obtained from HD patients and controls: TNF‐α (pg/mL), 31.40 ± 1.46 and 3.06 ± 0.15 (p < 0.001); IL‐8 (pg/mL), 90.98 ± 94.03 and 35.05 ± 16.86 (p < 0.001); PI, 1.69 ± 1.02 and 0.04 ± 0.02 (p < 0.001); GI, 0.82 ± 0.06 and 0.04 ± 0.02 (p < 0.001); and pocket depth, 2.23 ± 0.63 and 1.51 ± 0.05 (p < 0.001), respectively. In addition, there were positive correlations between TNF‐α and PI (r = 0.642, p < 0.001), between TNF‐α and GI (r = 0.565, p < 0.001), between TNF‐α and pocket depth (r = 0.522, p < 0.001), between IL‐8 and PI (r = 0.402, p = 0.002), between IL‐8 and GI (r = 0.396, p = 0.002), and between IL‐8 and pocket depth (r = 0.326, p = 0.012). There were negative correlations between albumin and PI (r = ?0.491, p < 0.001), albumin and GI (r = ?0.406, p < 0.001), albumin and pocket depth (r = ?0.464, p < 0.001) and albumin and CRP (r = ?0.467, p = 0.002) and between the gingival crevicular fluid levels of TNF‐α and IL‐8, TNF‐α and hemoglobin (r = ?0.745, p < 0.001; r = ?0.285, p < 0.05) (respectively). Conclusion: The levels of TNF‐α and IL‐8 in gingival crevicular fluid were significantly higher in HD patients than in controls. There were strong, positive correlations between clinical periodontal parameters and the levels of inflammatory cytokines in gingival crevicular fluid from the HD patients.     

Lethal outcome caused by Porphyromonas gingivalis A7436 in a mouse chamber model is associated with elevated titers of host serum interferon‐γ

Background/aims: Septic shock caused by gram‐negative bacteria has been associated with cytokines produced by hosts. Porphyromonas gingivalis A7436, a disseminating strain, caused septic shock‐like symptoms and even animal death in a mouse chamber model. However, P. gingivalis exhibits lower endotoxin activities in its lipopolysaccharide than other typical gram‐negative bacteria. In this study, we examined the effects of P. gingivalis lethal infection on host pro‐inflammatory cytokines production. Methods: Nude and normal BALB/c mice were infected with a lethal dose of P. gingivalis A7436 using a mouse chamber model. Serum levels of tumor necrosis factor, interleukin (IL)‐1β, IL‐12 and interferon‐γ were evaluated. The effects of tumor necrosis factor inhibitor (thalidomide) and anti‐interferon‐γ antibody on infection outcomes were examined. Results: All nude mice survived infectious challenge, whereas 100% of normal mice died with abdominal lesions. Bacterial cultures indicated P. gingivalis dissemination to the circulation. Serum levels of tumor necrosis factor, IL‐1β and IL‐12 showed no significant differences between nude and normal mice. Thalidomide treatment did not protect normal mice from death but decreased remote lesion occurrence, with concurrent reduced bacterial counts recoverable from blood. There was a 3.5‐fold elevation in normal mice serum interferon‐γ titers compared to those of nude mice and anti‐interferon‐γ antibody treatment resulted in 100% protection from lethal outcome. Conclusion: Lethal outcome following P. gingivalis A7436 infection is T‐lymphocyte dependent and involves an increase in systemic interferon‐γ levels. The data further indicate that P. gingivalis transvascular dissemination (bacteremia) alone is not sufficient for lethal outcome.     

Analysis of YKL‐40 Acute‐Phase Protein and Interleukin‐6 Levels in Periodontal Disease

Background: YKL‐40, a new acute‐phase protein, is shown to be elevated in inflammatory diseases, such as rheumatoid arthritis, type 2 diabetes mellitus, and coronary artery diseases. However, there is no data indicating a relationship between YKL‐40 and periodontal disease. Interleukin‐6 (IL‐6) is the major regulator of acute‐phase protein synthesis and one of the most studied inflammatory markers in periodontal disease. The purpose of the present study is to evaluate YKL‐40 and IL‐6 levels in gingival crevicular fluid (GCF) and serum of patients with periodontal disease and healthy individuals. Methods: Periodontally healthy individuals (n = 15), patients with gingivitis (n = 15), and patients with severe chronic periodontitis (CP) (n = 15) without any systemic disease were included in the study. Clinical measurements were recorded; GCF and blood samples were obtained from each participant. GCF and serum YKL‐40 and IL‐6 levels were analyzed by enzyme‐linked immunosorbent assay. Statistical analysis was performed by parametric and non‐parametric tests. Results: Total amounts of YKL‐40 and IL‐6 in GCF as well as serum YKL‐40 and IL‐6 levels were significantly higher in patients with gingivitis and CP compared with healthy controls (P <0.01). YKL‐40 levels in GCF and serum as well as serum IL‐6 levels were significantly higher in patients with CP compared with patients with gingivitis (P <0.01). Conclusions: YKL‐40 levels in GCF as well as serum YKL‐40 and IL‐6 levels increased from gingivitis to periodontitis. Within the limits of the present study, the YKL‐40 molecule might be a potential novel inflammatory marker of periodontal disease.     

Immunization by Arg‐gingipain A DNA vaccine protects mice against an invasive Porphyromonas gingivalis infection through regulation of interferon‐γ production

We previously demonstrated that a Porphyromonas gingivalis rgpA DNA vaccine induced protective immune responses against P. gingivalis infection in mice (Yonezawa et al. Infect Immun 2001: 69: 2858–2864). In the present study, reduction in lethality against infection by lethal doses of P. gingivalis was observed in the rgpA DNA vaccine‐immunized mice. Cytokine levels in the mouse model with nonlethal doses of infection by P. gingivalis were evaluated to analyze the mechanism of protection by immunization with the rgpA DNA vaccine. After nonlethal challenge with invasive P. gingivalis W50, production of interleukin (IL)‐2, IL‐4, IL‐5 and IL‐12 was elevated; however, interferon (IFN)‐γ was lower in the serum of the DNA vaccine‐immunized mice than in the serum of nonimmunized mice. The regulation of IFN‐γ production elicited by immunization with the rgpA DNA vaccine may play a significant role in protection against P. gingivalis infection in mice.