Iron absorption and oxidant stress during erythropoietin therapy in very low birth weight premature infants: a cohort study

BACKGROUND: Iron supplementation may be associated with oxidative stress particularly in premature infants. Our purpose was to examine 1) early supplemental iron during treatment with erythropoietin (EPO) and oxidative stress; 2) enhanced iron absorption during EPO in those infants receiving human milk. Therefore, we determined the effect of erythropoietin plus supplemental iron intakes (4 mg/kg/d) on antioxidant status and iron incorporation. METHODS: Ten very-low-birth-weight infants who were enterally fed and receiving either human milk or formula were followed for 4 weeks during erythropoietin therapy; blood and urine were collected at 3 times; baseline, 2 and 4 weeks later. Once oral feeds commenced the study protocol was initiated. After baseline blood collection, a dose of Fe(57 )was administered. Two weeks later, a dose of Fe(58 )was administered as ferrous chloride to determine the effect of human-milk or formula on iron incorporation into RBCs. RESULTS: Infants started the study at 35 ± 13 days. Incorporation of isotope into RBCs did not differ between formula fed for Fe(57 )(mean incorporation 8 ± 2.9 n = 3) compared to human-milk fed infants (8.7 ± 5 n = 7) nor for Fe(58 )(6 ± 2.7 n = 3 vs. 8.6 ± 5 n = 7). Tissue damage measured by malondialdehyde in plasma and F-2 – isoprostanes in urine, did not differ by feed or over time. Neither ability to resist oxidative stress/nor RBC superoxide dismutase differed according to feed or over time. CONCLUSION: Data suggest that during erythropoietin therapy antioxidant defence in VLBW infants are capable of dealing with early supplemental iron during treatment with EPO.