Plasma chain-breaking antioxidants in preterm infants with good and poor short-term outcome

Many complications of prematurity have been suggested to result from free r adical generation and an inadequacy of antioxidative capacity. We measured the plasma total peroxyl radical-trapping capability (TRAP) and concentrati ons of the main chain-breaking antioxidants contributing to it, i.e. uric a cid, ascorbic acid, a-tocopherol, protein sulfhydryl groups and bilirubin, in 21 preterm infants with a mean birth weight of 1440 g and gestational ag e of 30 wk. The infants were divided into two groups according to their sho rt-term outcome; the good outcome group (GOG) (N = 11) with no signs of mor bidity and the poor outcome group (POG) (N = 10) with intraventricular haem orrhage and/or bronchopulmonary dysplasia and/or retinopathy. Arterial bloo d samples were obtained 3 and 10 days postpartum. TRAP was measured with a chemiluminescent method. As a comparison, venous blood samples from 13 adul ts (aged from 18 to 34) were used. At day 3 the poor outcome group had sign ificantly higher TRAP than the good outcome or control group, mainly becaus e of elevated uric acid concentration. Also the concentration of unidentifi ed antioxidants was significantly lower in GOG. By day 10 the TRAP decrease d substantially in both groups. However, from the components of TRAP, both ascorbate and the unidentified fraction decreased more in FOG (p = 0.017 an d 0.021, respectively). Furthermore in FOG on day 10 urate concentration di d not significantly differ from day 3 values. In conclusion, in preterm inf ants high TRAP was associated with high plasma uric acid concentration and a poor short-term prognosis.