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Transferrin modifies surfactant responsiveness in acute respiratory failure: Role of iron‐free transferrin as an antioxidant
Author(s) -
Hallman Mikko,
Chundu Veeraiah,
Barsotti Michael,
Bry Kristina
Publication year - 1996
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/(sici)1099-0496(199607)22:1<14::aid-ppul3>3.0.co;2-k
Subject(s) - pulmonary surfactant , medicine , transferrin , transferrin saturation , hyperoxia , bronchoalveolar lavage , respiratory system , lung , chemistry , biochemistry , iron deficiency , anemia
In respiratory failure, transferrin (TF) with variable iron saturation accumulates in the alveolar space. Binding free iron to TF may inhibit metal‐catalyzed formation of free radicals. The aim of this study was to evaluate whether the degree of the iron‐saturation of TF influences the severity of respiratory failure and surfactant responsiveness. Surfactant deficiency and lung edema was induced in 42 paralyzed and ventilated young rabbits by bronchoalveolar lavage (BAL); 19 of these animals were preexposed to 100% O 2 for 40 hours. The animals received (1) exogenous surfactant intratracheally (100 mg/kg in 4 ml/kg saline); (2) surfactant and Fe 3+ ‐TF (50 or 25 mg/kg); or (3) surfactant and iron‐free TF (50 mg/kg). One hour after administration of TF, 13–25% of exogenous TF was recovered by BAL. Administration of iron‐free TF significantly decreased the iron saturation of TF in BAL. In acute respiratory failure induced by BAL, Fe 3+ ‐TF decreased the efficacy of exogenous surfactant in improving the gas exchange, and increased surfactant inhibition, while iron‐free TF had no effect. By contrast, in respiratory failure induced by hyperoxia and BAL, iron‐free TF improved the efficacy of exogenous surfactant, but Fe 3+ ‐TF had no effect. After administration of iron‐free TF, surfactant isolated from BAL was more surface‐active than surfactant from BAL of the other hyperoxia‐treated animals. In animals exposed to hyperoxia, treatment with iron‐free TF decreased malondialdehyde content of BAL. We propose that low iron saturation of TF decreases oxidant stress and favors the recovery from respiratory failure. Pediatr Pulmonol. 1996;22:14–22. © 1996 Wiley‐Liss, Inc.