Inflammatory cytokine level in patients with obstructive sleep apnea and treatment outcome of oral appliance therapy

Abstract

The aims of this study were to analyze the association between inflammatory cytokine and obstructive sleep apnea (OSA), and to evaluate treatment outcome and changes of plasma inflammatory cytokine levels after oral appliance therapy. Twenty-seven subjects who visited the Snoring and Sleep Apnea Clinic, Department of Oral Medicine in Seoul National University Dental Hospital were performed nocturnal polysomnography and analyzed plasma C-reactive protein (CRP), interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor (TNF)-α levels. Each subject was evaluated with Pittsburgh Sleep Quality Index (PSQI), and Epworth Sleepiness Scale (ESS). The subjects were classified into 12 OSA patients (Apnea-Hypopnea Index, AHI>5) and 15 control (AHI<5) groups. The OSA group was treated with mandibular advancement device (MAD) for 3 months and re-evaluated nocturnal polysomnography and plasma inflammatory cytokine levels.

The obtained results were as follows,

1. Plasma TNF-α, IL-10, and IL-6 levels were significantly higher in OSA patients compared to controls. (p<0.05) There were no significant differences in plasma CRP and IL-1β levels between the two groups.

2. Total AHI showed significant positive correlations with plasma IL-6 and TNF-α levels (p<0.01). Percentage time of SpO2<90 and lowest SpO2 were significantly correlated with plasma TNF-α level (p<0.05). ESS showed significant positive correlation with plasma IL-10 level (p<0.01). There were no significant correlations between PSQI or BMI and plasma cytokines levels.

3. Total AHI, percentage time of SpO2<90, lowest SpO2, and mean SpO2 were significantly improved after the MAD therapy. (p<0.05)

4. Plasma TNF-α level was significantly decreased after MAD therapy (p<0.01). There were no significant changes in plasma levels of CRP, IL-1β, IL-6 and IL-10 after MAD therapy.