Determinants of oxidant stress in extremely low birth weight premature infants

Early in life, premature neonates are at risk of oxidant stress. They often require total parenteral nutrition (TPN), which is, however, contaminated with oxidation products. Coadministration of parenteral multivitamins (MVP) with a lipid emulsion (LIP) prevents lipid peroxidation. We hypothesized that LIP + MVP induces a lower oxidant load compared to preparations in which MVP is administered with an amino acid solution (AA + MVP). The aim of this study was to compare markers of oxidant stress in premature neonates receiving LIP + MVP, either exposed to or protected from light, or AA + MVP. Antioxidant vitamins, the redox potential of glutathione, isoprostane, and dityrosine were measured in urine or blood sampled on days 7 and 10 from babies requiring low (< 0.25) vs high (≥ 0.25) fractional inspired O2. Oxygen supplementation induced a more oxidized redox potential and increased dityrosine with AA + MVP only. Adding MVP in the lipid rather than the amino acid moiety of TPN protects against the oxidant stress associated with O2 supplementation. Photoprotection added no benefit. Blood transfusions were found to produce a pronounced oxidant load masking the beneficial effect of LIP + MVP. The impact of these findings relates to a strong association between a more oxidized redox potential and later bronchopulmonary dysplasia, a clinical marker of oxidant stress.