Presence of bleomycin-detectable free iron in the alveolar system of preterm infants

Chronic lung disease: (CLD) is a major cause of long term morbidity in pret erm infants. Reactive oxygen species (ROS) play an important role in the pa thogenesis of CLD. We show that a high percentage (63 to 83%) of the invest igated bronchoalveolar secretions (BAS) of neonates contain bleomycin-detec table free iron concentrations (0.04-0.124 nmol/mu g SC, median range). Bes ide the presence of redox-active iron several iron-binding proteins like tr ansferrin, ferritin and lactoferrin were determined in BAS. Comparison of p rotein distribution within the first three days of life showed slight diffe rences between the group of preterm infants who developed CLD and the neona tes who recovered from RDS. Because of the existence of free iron we sugges t a higher risk of hydroxyl radical formation in the alveolar space. in an artificial system with addition of iron and hydrogen peroxide we were able to demonstrate OH-radical production in BAS by electron paramagnetic resona nce (EPR). OH-radical formation by H2O2 and iron in buffer solution was sli ghtly enhanced in the presence of BAS, indicating the absence of OH-radical -scavengers in BAS. (C) 1999 Academic Press.