Tissue fatty acid composition in obstructive sleep apnea and recurrent tonsillitis

Abstract

Objective: Tonsillar hypertrophy cells appear to have an altered lipid metabolism as evidenced by modulated inflammatory cytokines that affect tissue lipid metabolism. The aim of this study was to investigate differences in tissue fat composition between obstructive sleep apnea (OSA) and recurrent infective tonsillitis (RT) in children.

Methods: Tonsillar tissues were collected from 114 patients with OSA and 92 patients with RT, aged 4-10 years, during tonsillectomy. The tissue lipid extracts were analyzed by gas liquid chromatography for a comprehensive fatty acid profile.

Results: In the tonsillitis tissue, the levels of palmitoleic acid (16:1n-7; P=0.002) and oleic acid (18:1n-9; P=0.003) were higher, and the level of stearic acid (18:0; P=0.004) was lower than that in the hyperplastic tonsillar tissue. Overall, tonsillar tissue of patients with RT had a significant increase in the total monounsaturated fatty acids (+9.9%; P<0.001) and the fatty acid desaturation index (+20.5%; P<0.001). Furthermore, oleic acid content of tonsillar tissue was positively correlated with BMI (r=0.20, P=0.004), snoring (r=0.16, P=0.022) and hypertrophy grade (r=0.18, P=0.023), which remain significant in the subgroup analysis by hypertrophy type.

Conclusions: The change in the fatty acid composition may be regarded as an indicator of altered lipid metabolism occurring in vivo during human tonsillar hypertrophy, which might be linked to the severity or type of the tissue damage.