Plasma F2-isoprostanes are elevated in newborns and inversely correlated to the gestational age

F2-isoprostanes, prostaglandins F2-like compounds formed by free radical-catalyzed lipid peroxidation, are considered the most reliable markers of oxidative stress [1]. It has been repeatedly suggested that newborns are exposed to conditions of oxidative stress resulting from the change from a low oxygen pressure in utero to a high oxygen pressure at birth [2]. We measured the levels of F2-isoprostanes in plasma of newborns by gas chromatography/tandem mass spectrometry and we found that F2-isoprostanes are significantly higher in term newborns as compared to healthy adults. The greatest values were found in preterm newborns in whom F2-isoprostanes are even higher than in term babies. Moreover, a significant inverse correlation was found between the plasma levels of isoprostanes and the gestational age. A quite normal level of isoprostanes was found in mothers both at the delivery and during pregnancy. Placental total F2-isoprostanes (sum of free plus esterified) were significantly higher in preterm as compared to term deliveries. Whether such a difference accounts for the difference in plasma isoprostanes is under investigation. Plasma non-protein-bound iron is higher in preterm than in term newborns, even if no correlation was found with plasma F2- isoprostanes. Erythrocyte desferrioxamine chelatable iron content (0 time) and release (24 h of aerobic incubation) are higher in newborns than in adults and in preterm than in term newborns, but again no correlation was found with plasma F2-isoprostanes. The marked increase in plasma isoprostanes may suggest the possibility that lipid peroxidation, a major process of oxidative stress, occurs in newborns, and may contribute to the understanding of the so called ‘‘free radical disease of the neonate’’.