TOTAL PEROXYL RADICAL-TRAPPING CAPABILITY OF PLASMA IN PRETERM INFANTS

Abstract

Intensive care results in increased exposure to oxygen radicals and lipid peroxidation, while preterm infants may be unable to deal with such oxidative stress. We measured plasma total peroxyl radical-trapping capability (TRAP) and concentrations of various antioxidants in 21 preterm infants with a mean gestation of 30 wks (range 28-34). Arterial blood samples were taken at 3 and 10 days of age. All the infants needed supplementary oxygen, but none of the infants received vitamin supplementation. TRAP was measured with chemiluminescence, plasma concentrations of ascorbate and αtocophetol wilh IIPLC and those of urate, bilirubin and glutathione (GSH) with standard laboratory methods. Infants were divided into 2 groups: group 1 (n=9) with an unfavorable outcome (intracerebral hemorrhage (6) or death before the age of 10 d (3)), and group II (n=12) with a favorable short term outcome. The groups were similar in gestational age and birthweight. Group I needed more supplementary oxygen than group II at day 3 (59 vs 37 %), but not at day 10 (37 vs. 33%). Unexpectedly, group I had higher TRAP than group II at day 3 (2693 vs. 1103 μmol/l, p = 0.001). By day 10 the TRAP values consistently decreased, but the difference between groups persisted (2046 vs. 870 μmol/l, p=0.02). TRAP and urate concentration had a significant positive correlation, and urate explained 43% of TRAP. Group I had also higher concentration of ascorbate at day 3 than group II (67 vs. 20 μmol/l, p =0.001). The groups did not differ in: α-tocopherol, bilirubin and GSH concentrations. In conclusion, the infants with a poor outcome had significantly higher TRAP and plasma urate values than the children with a good outcome. This may rather be a consequence of preceeding tissue damage than a cause for subsequent problems.

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