Periodontal IL-6 Expression in Diabetic and Nondiabetic Patients

Objectives: Epidemiological studies have established that patients with diabetes have increased prevalence and severity of periodontal disease. However, the periodontal expression of inflammatory cytokines and matrix metalloproteinases (MMPs) in diabetic patients has not been well characterized. The objective of this study is to determine the difference in the periodontal expression of MMP-1, MMP-8, interleukin-6 (IL-6), tumor necrosis factor (TNF) alpha and IL-1 beta between diabetic and nondiabetic patients.

Methods: Periodontal tissue specimens were collected from 9 non-diabetic patients without periodontal disease (group 1), 11 non-diabetic patients with periodontal disease (group 2) and 7 diabetic patients with periodontal disease (group 3). The expression of MMP-1, MMP-8, IL-6, TNF alpha and IL-1 beta was quantified using real-time PCR.

Results: The nonparametric Kruskal-Wallis test showed that the difference in IL-6 expression among the groups was statistically significant (p = 0.04). Furthermore, the generalized Kruskal-Wallis nonparametric linear-by-linear association test showed a statistically significant trend of increase in the expression of IL-6 from group 1 to group 2 to group 3 (p=0.02) and a suggestion of such a trend in MMP-1 (p=0.05). No increase in MMP-8 expression was observed in patients in group 3 as compared to patients in groups 1 and 2. Although the average expression levels of MMP-1, IL-1 beta, and TNF alpha were increased from group 1 to group 3, the differences were not statistically significant.

Conclusion: A trend with increased IL-6 expression in periodontal tissues was observed across patients with neither diabetes nor periodontal disease, patients with periodontal disease alone, and patients with both diseases.

(This study was supported by NIH grant DE16353)