Since red blood cell transfusions are administered less frequently to very low birth weight (VLBW) infants, the risk of negative iron balance due to iatrogenic phlebotomy and rapid growth is increased. We investigated storage(liver (L)) and nonstorage (brain (B), heart (H) & skeletal muscle (SM)) tissue iron ([Fe]) and SM & H myoglobin ([Myo]) concentrations in 8 twin lamb pairs. Beginning at 3-4 d of life, twins were bled to 5-6 g Hb/dl and phlebotomized x3/wk thereafter (10 ml/kg) for 11 d. One twin was treated 3x/wk with i.v. saccharated iron (2, 5, 12 or 35 mg/kg); the other was not. Compared to the iv iron treated twins, non-iron treated phlebotomized lambs had lower mean (±SEM) tissue [Fe]'s (μg/g dry wt) in L, SM, H & B: Table L [Fe] was highly correlated with dose(r = 0.98, P <0.001); Ln of L[Fe] correlated with B, H& SM (r = 0.84, r = 0.91 & r = 0.63, respectively). A significant dose effect of iron treatment on tissue [Fe]'s was observed in L, SM, H & B (P <0.05, ANOVA). H and SM [Myo] declined significantly in association with H and M [Fe] (r = 0.79& r = 0.59). Reduced tissue [Fe]'s and parallel decreases in tissue [Myo] would likely have adverse physiologic consequences on B, H and SM function in non-treated lambs. Evaluation of and treatment to improve iron status in phlebotomized VLBW infants may be important in avoiding iron deficiency.

Table 1
Full size table