HYPOXIA-INDUCED FREE IRON RELEASE IN THE RED-CELLS OF NEWBORN-INFANTS

Heparinized blood samples were obtained at birth from 164 newborn infa nts (101 full term; 63 preterm). Intra-erythrocyte free iron concentra tion and hypoxanthine plasma levels were determined by high-pressure L iquid chromatography. Intra-erythrocyte free iron concentration was hi gher in preterm than in full term babies (p < 0.0001) and adults (p < 0.0001). Statistically significant correlations were observed between intra-erythrocyte free iron concentration and hypoxanthine levels (r = 0.66;p = 0.0001), pH (r = -0.76; p = 0.0001), base excess (r = -0.79; p = 0.0001), and gestational age (r = -0.44; p = 0.0001) in both infa nt populations. Multiple regression analysis between intra-erythrocyte free iron concentration in cord blood, as an independent variable, an d Apgar score at 1 min, pH, base excess, hypoxanthine values, FiO(2) n eeded for resuscitation immediately after delivery, and gestational ag e, as dependent variables, identified hypoxanthine levels (p = 0.0003; partial F-test = 15.4) as the best single predictor of intra-erythroc yte free iron concentration. In conclusion, hypoxia induces intra-eryt hrocyte free iron release, and therefore enhances the risk of oxidativ e injury due to hydroxyl radical generation.