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Hypoxia-induced free iron release in the red cells of newborn infants
G Buonocore1, S Zani, I Sargentini
1Istituto di Pediatria Preventiva e Neonatologia, Università degli Studi di Siena, Italy.
Insights
Hypoxia in newborns increases intra-erythrocyte free iron, raising oxidative injury risk. Hypoxanthine levels are a key predictor of this iron release in infants.
Area of Science:
- Neonatal Medicine
- Biochemistry
- Pediatric Research
Background:
- Neonatal iron homeostasis is critical for development.
- Oxidative stress is a significant concern in preterm infants.
- Understanding factors influencing iron levels in newborns is essential.
Purpose of the Study:
- To investigate the relationship between intra-erythrocyte free iron and hypoxanthine levels in newborns.
- To explore correlations between intra-erythrocyte free iron and physiological parameters in term and preterm infants.
- To identify predictors of intra-erythrocyte free iron concentration in cord blood.
Main Methods:
- Collected heparinized blood samples from 164 newborns (101 full term, 63 preterm).
- Quantified intra-erythrocyte free iron and plasma hypoxanthine using high-pressure liquid chromatography.
- Performed statistical analyses including correlation and multiple regression.
Main Results:
- Higher intra-erythrocyte free iron in preterm infants compared to full-term infants and adults.
- Significant correlations found between free iron and hypoxanthine, pH, base excess, and gestational age.
- Hypoxanthine levels identified as the best predictor of intra-erythrocyte free iron concentration.
Conclusions:
- Hypoxia is linked to the release of intra-erythrocyte free iron in newborns.
- This iron release potentially increases the risk of oxidative injury via hydroxyl radical generation.
- Findings highlight the importance of monitoring hypoxanthine levels in neonatal care.
Abstract:
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.