Cytokine changes after surgical treatment of obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is associated with inflammatory processes and elevated plasma cytokines. This study assesses the effect of surgery in cytokine levels of OSAS patients. A total of 24 male patients with mild to moderate OSAS, confirmed with polysomnography underwent septoplasty and uvulo-palato-pharyngoplasty in a period of a year. Control group consisted of 12 overweighted subjects and 15 obese subjects. Peripheral venous blood was collected from each patient 1 week before surgical treatment and 6 months postoperatively. Spontaneous production of tumour necrosis factor (TNF-a) by monocytes and serum levels of IL-1 beta and IL-6 were investigated. Control subjects were also examined for the same pro-inflammatory cytokines. Production of TNF-a and IL-6 were significantly elevated in OSAS patients and obese controls compared with overweighted control subjects (p < 0.05). Serum levels of IL-1 beta did not differ among the study groups. Preoperative cytokine values were significantly correlated with the preoperative body mass index (BMI) and the apnoea/hypopnoea index (AHI) in OSAS patients. Surgery resulted a significant reduction in the TNF-a and IL-6 values of the study group. Decrease in cytokine level was strongly correlated with the AHI decrease. The postoperative relative percentage change of IL-6 values was significantly higher than this of TNF-a (p < 0.001). Surgical management of mild to moderate OSAS leads to a significant reduction in TNF-a and IL-6 values. Our data indicate that AHI is an independent risk factor of systemic inflammation; however it affects cytokines to a lesser degree compared with the BMI.