Document Type

Thesis

Date of Degree

2008

Degree Name

MS (Master of Science)

Degree In

Oral Science

First Advisor

Janet Guthmiller

Abstract

Background: The role of cytokines in the pathogenesis of periodontal disease and the effect of smoking on these mediators has been reported. However, findings have been variable and simultaneous measurement of multiple cytokines has been limited. This study utilized a quantitative multiplex assay to measure a comprehensive panel of Th1, Th2, and pro-inflammatory cytokines and chemokines (including several novel cytokines) in gingival crevicular fluid (GCF) in chronic periodontitis subjects. The impact of cigarette smoking on these GCF mediators was also assessed.

Methods: Forty subjects (age 40-75 years) with generalized severe chronic periodontitis (20 smokers and 20 non-smokers) and 12 periodontally healthy controls participated in the study. GCF was collected from four sites in the diseased groups: 2 diseased sites [(probing depth (PD) and clinical attachment level (CAL) ≥5mm with bleeding on probing (BOP)] and 2 healthy sites (PD and CAL ≤3mm, no BOP); 2 healthy sites were sampled in the healthy controls. The volumes of the GCF samples were measured and the GCF mediators assessed in duplicate utilizing a multiplex immunoassay (Luminex). Intragroup, intergroup and pooled comparisons were performed using non-parametric tests including the Mann-Whitney and the Wilcoxon matched-pairs signed-rank test.

Results: GCF in diseased sites (vs. controls) contained significantly (p<0.05) higher amounts of IL-2, IFN-γ, IL-3, IL-4 (Th1/Th2 cytokines); IL-1α, IL-1β, IL-6, IL-12 (p40) (pro-inflammatory cytokines); IL-8, MIP-1, RANTES (chemokines); and IL-15 (regulator of T-cells and NK cells). IP-10 was the only mediator exhibiting lower levels (p<0.0005) in diseased sites compared to controls. Smoking had an inhibitory effect (p<0.05) on pro-inflammatory cytokines (IL-1α, IL-6, IL-12 (p40)); chemokines (IL-8, IP-10, MCP-1, MIP-1, RANTES) and regulators of T-cells and NK cells (IL-7, IL-15) in comparison to sites within non-smokers. Interestingly, smokers had elevated GCF levels (p<0.05) of IL-1α, IL-1β and IL-3 relative to sites in healthy controls.

Conclusions: Similar to previous reports, periodontitis subjects had significantly elevated cytokines and chemokines compared to healthy controls. Smokers exhibited a decrease in several pro-inflammatory cytokines, chemokines and regulators of T-cells and NK-cells as compared to nonsmokers however; little influence was observed on Th1/Th2 cytokines. Interestingly, smokers exhibited decreased amounts of GCF IL-7, IL-12(p40), IL-15, IP-10, MCP-1, MIP-1 and RANTES, which calls for future investigation. The multiplex comprehensive assay used in this study to assess cytokines in a single GCF sample is a significant advancement. This technology can be used to compare serum and GCF cytokine profiles in periodontitis and correlate systemic and localized immune responses. This should provide insight into the impact of smoking, as well as other host modifiers, on important systemic and periodontal interactions.

Keywords

Smoking, periodontal disease, immune response, periodontitis/etiology, periodontitis/therapy, marker, chronic periodontitis, gingival crevicular fluid

Pages

vii, 107 pages

Bibliography

Includes bibliographical references (pages 101-107).

Copyright

Copyright 2008 Keelen D Tymkiw

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