Oxidative stress markers in neonatal respiratory distress syndrome: advanced oxidation protein products and 8-hydroxy-2-deoxyguanosine in relation to disease severity

OBJECTIVE: We assessed oxidant-antioxidant status and evaluated the role of lipid peroxidation, oxidative DNA damage, and protein oxidation in the development and severity of neonatal respiratory distress syndrome (RDS). METHODS: Forty preterm neonates with RDS were compared with another 40 preterm neonates without RDS enrolled as controls. Total antioxidant capacity (TAC), malondialdehyde (MDA), advanced oxidation protein products (AOPPs), 8-hydroxy-2-deoxyguanosine (8-OHdG), and trace elements (copper and zinc) were measured in cord blood (day 0) for all neonates and repeated on day 3 for the RDS group. RESULTS: Day 0 serum levels of MDA, AOPPs, and 8-OHdG were significantly higher in neonates with RDS than controls with a further increase on day 3. Days 0 and 3 levels of TAC, copper, and zinc were significantly lower in the RDS group compared with controls. Elevated serum levels of 8-OHdG and AOPPs were associated with severe RDS, invasive mechanical ventilation, and high mortality rate. 8-OHdG and AOPPs were positively correlated with MDA, oxygenation index, duration of ventilation, and duration of hospitalization. CONCLUSIONS: Increased lipid, protein, and DNA oxidation is accompanied by alterations in the antioxidant defense status, which may play a role in the pathogenesis and severity of RDS.