Urinary concentration of 8-isoprostane as marker of severity of pediatric OSAS

BACKGROUND: F2-isoprostanes are considered to be a reliable standard biomarker of oxidative stress in vivo because they are not influenced by the intake of lipids in the diet, and they are chemically stable molecules and easily detected. This study aimed to test the hypothesis that 8-isoprostane level is a useful marker to valuate the severity of pediatric obstructive sleep apnea (OSA). METHODS: Sixty-five children with sleep-disordered breathing (SDB) (mean age 5.9 ± 2.0 years; 63.1 % males) were recruited. The urine sample for the measurement of 8-isoprostane was collected the morning after the polysomnographic recording. Children were divided into two groups according to their apnea-hypopnea index (AHI). RESULTS: Urinary 8-isoprostane levels positively correlated with the sleep clinical record score (r = 0.38, p = 0.002) and AHI (r = 0.24, p = 0.05) and negatively correlated with age (r = -0.36, p = 0.003) and body surface area (r = -0.38, p = 0.002). Urinary 8-isoprostane levels were significantly higher in the group with AHI of ≥5 events (ev)/h than in the group with AHI of <5 ev/h (p < 0.01). CONCLUSIONS: Urinary 8-isoprostane may be used as a specific inflammatory marker to predict the severity of OSA; this method has the advantage of being noninvasive and easy to use in both compliant and noncompliant children.