ROLE OF INNATE IMMUNITY FACTORS IN PERIODONTITIS PATHOGENESIS

Cytokine profile of gingival crevicular fluid in children with impaired immunological surveillance system

Aim. To study the cytokine profile of the gingival crevicular fluid (GCF) in children with a juvenile rheumatoid arthritis (JRA).

Materials and methods. We examined 20 children with JRA and 10 patients without somatic pathology aged 6 to 16 years old. The condition of periodontal tissues was assessed by periodontal indices – gingival index GI (Loe, Silness, 1963) and gingival bleeding index GBI. Biomaterial sampling from the gingival sulcus was carried out using special endodontic absorbent paper points. Enzyme immunoassay for IL-18, IL-10, IL-1ß, IL-1RA, MCP-1, VEGFs in the GCF was performed using the test kits of Vector-Best LLC (Novosibirsk, Russia).

Results. Mean GI index in the JRA group was 0.31 ± 0.10 and in the control group – 0.20 ± 0.05 (p < 0.05), mean GBI index – 19.90 ± 3.14 and 10.80 ± 2.60 respectively (p < 0.05), which was accompanied by a more pronounced degree of inflammation of periodontal tissues. The GCF concentration of IL-18 in the JRA group was 6.70 (4.97–7.92) pg/ml, in the control group – 11.25 (8.70–13.10) pg/ml (p < 0.05), while the concentration of IL-1ß was 15.30 (13.79–17.18) pg/ml in the JRA group and 5.36 (5.32–5.54) pg/ml in the control group.

The IL-10 concentration in the JRA group was 3.60 (2.89–4.45) pg/ml, which was comparable to the values of the control group. The concentration of IL-1RA was lower in the JRA group than in the control group: 3638.5 (2397.5–4133.5) pg/ml and 4951.0 (4303.0–5455.0) pg/ml respectively. The total GCF chemokine concentration for MCP-1 was determined at the level of 15.65 (14.15–17.39) pg/ml and 15.50 (12.80–21.20) pg/ml for the main and control groups and for VEGF – 49.60 (41.95–54.50) pg/ml in the JRA group and 12.00 (11.00–13.00) pg/ml in control group.

Conclusion. In children with juvenile rheumatoid arthritis, an imbalance of pro- and anti-inflammatory cytokines in GCF plays a role in the development of gingivitis: an increased of IL-1ß concentration – a triggering factor of pro-inflammatory chains, a decreased concentration of IL-1RA – an anti-inflammatory cytokine, an increased concentration of VEGF – a marker of hypoxia.

Correlation of marker periodontopathogenic bacteria with the immune component sCD14 secretion level in inflammatory periodontal diseases

Lipopolysaccharide of the cell wall of gram-negative bacteria is a highly active biological substance: its interaction with toll-like receptors-4 (TLR-4) of myeloid cells leads to the activation of a cascade of inflammatory reactions, which is accompanied by the release of the soluble CD14 receptor (sCD14), which can be considered not only as a marker of cell activation by endotoxin, but also as a marker of microbial translocation. The aim of the work was to assess the prognostic significance of the sCD14 level in the samples of the periodontal pocket in inflammatory periodontal diseases and the relationship of its secretion with marker periodontopathogens. For the study, washes were obtained from the periodontal pocket (88 samples in total) from patients with chronic periodontitis and intact periodontium. The sCD14 content was determined by ELISA; during real-time PCR, the marker periodontopathogens Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Treponema denticola, Porphyromonas gingivalis, Prevotella intermedia, and Candida albicans were isolated. The study revealed differences in the level of sCD14 secretion by groups: in chronic periodontitis, its content was 8,5 times higher than in the control group and amounted to 17,2±4,06 ng/ml (p=0,006). The frequency of detecting genes of periodontal pathogenic bacteria was 89,3% in patients with periodontitis and 31,25% in the group with intact periodontium. An interesting dependence of the detection of periodontal pathogenic bacteria in the group of patients with chronic periodontitis was established depending on the content of sCD14. Thus, at high concentrations of soluble coreceptor, a greater number of periodontopathogenic bacteria of the I and II orders were released. Thus, in inflammatory periodontal diseases, the processes of sCD14 synthesis change, which is probably due to the colonization of periodontal pathogenic bacteria and the action of their toxins and aggression factors. The relationship of marker periodontopathogens with the level of secretion of the immune component sCD14 and its effect on the structure of the periodontal index reflect shifts in the processes of reparative regeneration of the oral mucosa and the regulation of local immunity in response to microbial invasion.

[Antibacterial effect of a non-specific immunomodulator based on muramilpeptides in chronic periodontitis]

THE AIM OF THE STUDY

Was to investigate the efficacy of immunomodulatory drug based on muramilpeptides for treatment of chronic generalized periodontitis.

MATERIALS AND METHODS

The study group comprised 20 patients aged 25 to 64 with severe chronic periodontal disease. Periodontal pockets content was inoculated for specific microbial pathogens before and after treatment. Twenty patients receiving conventional treatment with no muramilpeptides-based agent served as controls.

RESULTS

In the main group prolonged suppression of periodontal disease provoking microbiota was seen, while in controls conventional treatment was not sufficiently effective resulting in germs growth relapse at day 21.

CONCLUSION

The dynamics of the microbiological landscape of periodontal pockets after treatment proves the necessity for a correction of innate immunity in inflammatory periodontal disease.

IL-21/anti-Tim1/CD40 ligand promotes B10 activity in vitro and alleviates bone loss in experimental periodontitis in vivo

IL-10-expressing regulatory B cells (B10) play an essential role in immune system balance by suppressing excessive inflammatory responses. In this study, we investigated induction of B 10 cell's IL-10 competency in vitro and its effect on ligature-induced experimental periodontitis in vivo. Spleen B cells were isolated from C57BL/6J mice and cultured for 48h under the following conditions: control, CD40L, IL-21, anti-Tim1, CD40L+IL-21, CD40L+anti-Tim1, CD40L+IL-21+anti-Tim1. Silk ligatures were tied around both maxillary second molars of C57BL/6J mice for two weeks. Optimized combination of CD40L, IL-21 and anti-Tim1 and vehicle were injected into contralateral side of palatal gingiva on days 3, 6 and 9. The palatal gingival tissues and maxillary bone were collected on day 14 to determine expressions of IL-10 and periodontal bone resorption respectively. Our results demonstrated that IL-10 expressions of cultured spleen B cells were significantly increased in the presence of CD40L, IL-21 and anti-Tim1 combination when compared with control groups. Gingival IL-10 mRNA and protein expressions were significantly increased after injection of CD40L, IL-21 and anti-Tim1 combination, when compared to the control side. The gingival RANKL expression and periodontal bone loss were significantly decreased on the combination treatment side, as compared to the control side. These results suggest that combination of IL-21, anti-Tim1 and CD40L treatment induced B10 cell's IL-10 competency in vitro and inhibited periodontal bone loss in ligature-induced experimental periodontitis.

Salmeterol, a Long-Acting β2-Adrenergic Receptor Agonist, Inhibits Macrophage Activation by Lipopolysaccharide From Porphyromonas gingivalis

BACKGROUND

Salmeterol is a long-acting β2-adrenergic receptor agonist used to treat chronic obstructive pulmonary disease. The authors of the current study previously showed that preincubation of primary microglial-enriched cells with salmeterol could inhibit the inflammatory response induced by Escherichia coli lipopolysaccharide (LPS), a Toll-like receptor (TLR)-4 agonist. In this study, the authors sought to determine if salmeterol had a similar inhibitory effect on the inflammatory response of the murine macrophage cell line RAW264.7 and human monocyte THP-1 to LPS from Porphyromonas gingivalis (PgLPS), an oral microbe implicated in the pathogenesis of periodontal disease.

METHODS

RAW264.7 and THP-1 cells were pretreated with salmeterol, followed by PgLPS, and monitored for production of inflammatory mediators by enzyme-linked immunosorbent assay. The nitric oxide concentration and nuclear factor-kappa B (NF-κB) activity were measured by Griess method and secretory alkaline phosphatase reporter activity assay, respectively. Reverse-transcriptase polymerase chain reaction and immunoblot analysis were used to measure messenger RNA and protein levels. Nuclear translocation of NF-κB was detected by immunofluorescence.

RESULTS

Pretreatment with salmeterol significantly inhibited production of proinflammatory mediators by RAW264.7 and THP-1 cells. Salmeterol downregulated PgLPS-mediated phosphorylation of the extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase but not p38 mitogen-activated protein kinases (MAPKs). Salmeterol also attenuated activation of NF-κB via inhibition of nuclear translocation of p65-NFκB, the transcriptional activity of NF-κB and IκBα phosphorylation.

CONCLUSION

Salmeterol can significantly inhibit activation of macrophage-mediated inflammation by PgLPS, suggesting that use of salmeterol may be an effective treatment in inhibiting or lessening the inflammatory response mediated through TLR pathway activation.

Potential relationship between periodontal diseases and eye diseases

Periodontal diseases are inflammatory lesions initiated by oral bacteria and lead to the destruction of the supporting structures of the teeth (gingiva, periodontal ligament and alveolar bone) in susceptible patient. Via several biological mechanisms, periodontal diseases have been associated with multiple systemic diseases, such as rheumatoid arthritis, diabetes, cardiovascular diseases, Alzheimer's disease and adverse pregnancy outcomes. Similarly certain eye diseases have been associated with systemic diseases of the inflammatory pathway. We hypothesized that periodontal diseases are associated with eye diseases. Thus using literature data we find that several studies have reported that eye disorders are associated with the presence of periodontal diseases. But the mechanisms of this relationship are not clear. However the innate immune response involvement, the sharing of similar risk factors in pathogenesis and the changes of eye choroid thickness may be suggested as several hypotheses to explain this potential association.