Association of the Unstimulated Whole Salivary Cytokine IL-1β Levels with Initial, Moderate and Severe Periodontitis. A Case Control Study

Periodontitis (P) is a highly prevalent inflammatory disease of the oral cavity. The objective of the study was to evaluate the stages of pro-inflammatory cytokine IL-1β in initial, moderate and severe periodontitis. One hundred and twenty two patients were included in the study. Periodontitis subjects had at least 20 natural teeth and ≥8 sites with pocket depths of >4 mm and clinical attachment loss (CAL). A questionnaire was used with respect to the socio demographic parameters which included age, gender, ethnicity, education, marital, residence and occupation. To categorize the severity of the disease, teeth were assessed for, Plaque index (PI), Bleeding on probing (BOP), CAL, missing tooth, tooth mobility and bone loss. Unstimulated whole saliva (UWS) was collected and Interleukin-1β (IL-1β) cytokine levels were analyzed using enzyme linked immunosorbent assay with microplate reader at 450 nm. Clinical parameters and salivary cytokine concentrations were assessed using one-way analysis of variance, whereas a correlation of cases with gender and severity of periodontitis was evaluated using chi-square test. Fifty-nine patients were healthy controls and 63 were periodontitis patients Thirty two percent (n = 20) had initial periodontitis, 40% (n = 25) suffered from moderate and 29% (n = 18) had severe periodontitis. Periodontitis subgroups were significantly different with regards to age and gender (p < 0.001). The mean PPD and CAL among the periodontitis patients (PPD, 3.52 ± 1.25 mm; CAL, 4.04 ± 1.64 mm) were significantly compromised (p < 0.05) compared to healthy controls (PPD, 1.52 ± 0.73 mm; CAL, 0.08 ± 0.28 mm). Increased levels of IL-1β were associated with high CAL and PPD findings. UWS IL-1β levels were higher in periodontitis patients compared to healthy individuals. In addition, cases of severe periodontitis showed significantly higher UWS IL-1β levels compared to initial and moderate periodontitis patients. Comparative levels of salivary IL-1β can be potentially used as a diagnostic tool for periodontitis identification and disease progression along with clinical parameters.

Correlation of Toll-like receptor 4, interleukin-18, transaminases, and uric acid in patients with chronic periodontitis and healthy adults

BACKGROUND

Because of the potential association between periodontal disease and inflammation, the purpose of the present study is to examine the level of Toll-like receptor 4 (TLR-4), interleukin-18 (IL-18), and uric acid as markers of the inflammatory host response in the plasma and saliva of healthy individuals and patients with periodontitis. In addition, routine biochemical parameters such as fasting glucose, insulin, total cholesterol, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, triglycerides, alanine transaminase (ALT), and aspartate transaminase (AST) were measured. The authors also wanted to check whether patients with chronic periodontitis (CP) exhibit different modulations in salivary and/or plasma concentrations of these parameters compared with clinically healthy individuals.

METHODS

Saliva and plasma samples were collected from 40 patients with CP and 20 healthy individuals. TLR-4 and IL-18 measurements were done using commercially available enzyme-linked immunosorbent assay kits. Total, HDL, and LDL cholesterol; triglycerides; fasting glucose; AST; and ALT levels were analyzed on a biochemistry analysis system using specific kits. Non-parametric tests were used for certain parameters in the statistical analyses because the data did not follow Gaussian distribution.

RESULTS

Significant differences were observed in plasma and salivary TLR-4 and IL-18 levels, along with clinical measurements such as plaque index and probing depth, in patients with CP (P < 0.001). The plasma level of TLR-4 was found to be increased from 0.99 to 3.28 ng/mL in patients with CP. Salivary TLR-4 levels also showed a slightly higher increase in the diseased state (12.44 to 29.97 ng/mL). A significant increase of ≈ 46% was recorded in the plasma IL-18 level. However, salivary IL-18 levels rose up to > 5-fold in the patients with CP compared with healthy individuals. The level of plasma uric acid was found to be highly significantly increased compared with control individuals. HDL cholesterol and triglyceride also showed significant differences (P < 0.02 and P < 0.03, respectively). Plasma glucose, total cholesterol, LDL cholesterol, and insulin levels did not show any significant difference. There was only a slight increase in plasma AST and ALT levels between diseased and healthy states (22.55 versus 25.50 IU/L and 12.35 versus 15.95 IU/L, respectively). However, salivary AST and ALT levels showed a ≈ 6-fold rise in the patients with CP compared with the healthy individuals. Cross-correlation analysis in the periodontitis disease group showed a significant association of plasma AST, salivary AST, and salivary ALT with uric acid level.

CONCLUSIONS

Based on this study, the authors believe that TLR-4, IL-18, and uric acid could have a role in the inflammatory pathology of periodontitis. These parameters are suggested to be useful in the prognosis and diagnosis of CP. However, the mechanistic association of these parameters with inflammatory pathology of patients with periodontitis needs to be further elucidated in a higher number of samples.