Antioxidants and Biomarkers of Oxidative Stress in Preterm Infants with Symptomatic Patent Ductus Arteriosus.

OBJECTIVE

Immature antioxidant and oxygen-sensing mechanisms are involved in the pathogenesis of the patent ductus arteriosus (PDA). We conducted a prospective, observational, pilot study to test the hypothesis that antioxidant activity is low at birth in preterm infants at risk for symptomatic PDA.

STUDY DESIGN

Blood and urine samples were collected within 24 to 48 hours of life in 53 preterm infants (≤32 weeks' gestation) who developed early PDA symptoms and in 30 term (≥37 weeks' gestation) control infants. Thirty preterm infants developed hemodynamically significant PDA (hsPDA) and required pharmacologic treatment and/or PDA ligation. For these infants, blood and urine samples were also collected at 24 hours posttreatment. Samples were analyzed for biomarkers of antioxidant activity, oxidative stress, and lipid peroxidation.

RESULTS

At 24 to 48 hours after birth, plasma superoxide dismutase (SOD), urinary catalase, and plasma and urinary 8-isoPGF2α were significantly lower in preterm infants who developed hsPDA. Plasma 8-isoPGF2α levels rebounded post-PDA treatment, while urinary prostaglandin E2, plasma and urinary thromboxane B2, and plasma SOD declined.

CONCLUSION

The antioxidant status is low in preterm infants at risk for developing hsPDA. SOD may be a key antioxidant regulating functional ductus arteriosus closure. Therefore, low levels may result in persistence of a hsPDA.