Anti-oxidant enzymes and related elements in term and preterm newborns

Background : Although oxidative stress-related diseases mostly affect neonates with extremely low birthweight, healthy preterm newborns might also be at risk of oxidative damages. The aim of the present study was to verify this possibility. Methods : Urinary 8-hydroxy-2 -deoxyguanosine (8-OHdG), erythrocyte glutathione peroxidase (GSHPx) and superoxide dismutase (SOD), plasma and erythrocyte concentrations of selenium, zinc and copper were measured until 100 days of life in 30 preterm infants with mean ± SD birthweight and gestational age of 1605 ± 122 g and 34.5 ± 0.5 weeks. The control group included 30 term infants with birthweight 3123 158 g and gestational age 39.6 0.7 weeks. Results : Throughout the study period urinary 8-OHdG, taken as a marker of oxidative stress, was signifi cantly higher in the preterm than in the term group. Up until 20 days of life, GSHPx activity was signifi cantly lower in the preterm than in the term infants but this was not associated with any apparent selenium defi ciency. Conversely, up until 100 days, preterm infants had signifi cantly reduced SOD levels that appeared to refl ect a shortage of the elements needed for this enzyme’s activity, notably copper, the plasma concentrations of which were constantly and signifi cantly below the control values. Conclusion : The nutritional status of the elements related to the anti-oxidant enzymes, especially zinc and copper, should be carefully assessed in preterm infants, even if their birthweight is not extremely low.