Oxidative stress in newborn infants with and without asphyxia as measured by plasma antioxidants and free fatty acids

A rapid perfusion of oxygen in infants at birth may cause an increase of ox idative stress. To assess this possibility, we measured levels of blood pla sma antioxidants and free fatty acids in 20 normal infants at 0, 1, 3, and 5 days after birth. Plasma levels of the most reactive antioxidant, ascorbi c acid, decreased daily to equilibrium values at days 3 and 5. Percentages of oxidized form of coenzyme Q-10 (%CoQ-10) in total coenzyme Q, another go od marker of oxidative stress, in infants (25-31%) were significantly highe r than those in healthy young adults (4.5%). Plasma levels of total free fa tty acids (FFA) in normal infants were highest at day 1 and decreased rapid ly thereafter. The content of polyunsaturated fatty acids (PUFA) in total F FA was lowest at day 1 and then increased. Since PUFA are susceptible to ox idation, these changes in FFA composition suggest that oxidative stress is most evident at the initial day of neonatal life. Furthermore, it appears t hat mono-unsaturated fatty acids such as oleic and palmitoleic acids increa se in response to the oxidative loss of PUFA. Similar changes in plasma ant ioxidants, FFA levels, and FFA compositions were observed in 9 infants with asphyxia, Values of %CoQ-10 in infants with asphyxia were significantly gr eater than those in normal infants, suggesting that infants with asphyxia h ave elevated oxidative stress. (C) 1999 Academic Press.