Hypoxia-induced free iron release in the red cells of newborn infants.
Heparinized blood samples were obtained at birth from 164 newborn infants (101 full term; 63 preterm). Intra-erythrocyte free iron concentration and hypoxanthine plasma levels were determined by high-pressure liquid chromatography. Intra-erythrocyte free iron concentration was higher 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 infant populations. Multiple regression analysis between intra-erythrocyte free iron concentration in cord blood, as an independent variable, and Apgar score at 1 min, pH, base excess, hypoxanthine values, FiO2 needed for resuscitation immediately after delivery, and gestational age, as dependent variables, identified hypoxanthine levels (p = 0.0003; partial F-test = 15.4) as the best single predictor of intra-erythrocyte free iron concentration. In conclusion, hypoxia induces intra-erythrocyte free iron release, and therefore enhances the risk of oxidative injury due to hydroxyl radical generation.
Buonocore
G
G
Istituto di Pediatria Preventiva e Neonatologia, Università degli Studi di Siena, Italy.
Zani
S
S
Sargentini
I
I
Gioia
D
D
Signorini
C
C
Bracci
R
R
D000328:Adult; D004912:Erythrocytes / Q000378:metabolism*; D005260:Female; D005293:Ferritins / Q000097:blood*; D005312:Fetal Blood / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000150:complications*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood*; D016014:Linear Models; D008297:Male; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism*; D012016:Reference Values; D012044:Regression Analysis
D017382:Reactive Oxygen Species; D005293:Ferritins