The Postnatal Hypotransferrinemia of Early Preterm Newborn Infants

Abstract

ExtractPreterm newborns were found to be markedly hypotransferrinemic when compared with normal term infants. At birth the concentration of transferrin in sera from preterm infants of gestational age equal to or less than 32 weeks is 45% of that found in normal term infant sera. The preterm infant transferrin levels slowly rise so that 7-8 weeks after birth they are 78% of the level found in the sera of normal term infants. We also found that the serum transferrin concentrations at birth correlate with gestational age. Therefore, the transferrin levels postnatally in early preterm infants reflect postconceptional rather than postnatal age. Specula tionSince we found that early preterm newborns are markedly hypotransferrinemic, administration of iron to such infants during their first few postnatal months may be contraindicated. Harmful side effects of iron during this period might include an increased susceptibility to infection because of the known bacteriostatic and fungistatic activities of iron-free transferrin.The serum iron-binding protein transferrin has been known to possess bacteriostatic and fungistatic activities since it was first described by Schade and Caroline in 1946 (20). Subsequently, the function of transferrin as an iron transport protein has been well established (14), but the role of transferrin in nonspecific immunity still remains to be clarified completely.Nevertheless, the results of many recent studies have reiterated the bacteriostatic properties of serum transferrin in vitro and in vivo in experimental animals. I t has been concluded that iron-free transferrin is bacteriostatic because it can compete successfully with many pathogens for iron when this essential nutrient is present in limiting amounts (4-7, 10, 19,22). Such a mechanism of bacteriostasis is reasonable considering the extraordinarily high affinity which transferrin has for iron (I).In the normal human, serum transferrin is only 30-40% saturated with iron. Many pathologic states in which the saturation of transferrin with iron is elevated are associated with an increased occurrence of infection (7,23, 24). When children with kwashiorkor, whose transferrin levels are severely depressed (17), are given iron therapy before their transferrin levels become normal, a high incidence of death from infection ensues (18). Taken together, these various clinical observations support the concept that transferrin may play a role in nonspecific immunity to bacterial and fungal infections.The transferrin in sera of newborns is highly saturated with iron (2 1). Since early preterm newborn infants are particularly susceptible to infection, the aim of this study was to examine the transferrin levels in the sera of these infants during their first few months of life. MATERIALS AND METHODSTransferrin was purified from a pool of outdated human blood by a modification of a method described previously (16). Eight hundred milliliters of plasma were diluted in the cold with 800 ml 0.01 M Tris-HCI, pH 8.8. Nonglobulin proteins were precipitated by...

Known and potential roles of transferrin in iron biology

“…Postnatal hypotransferrinemia has been noted in preterm newborn infants where serum TF levels correlated with postconceptional rather than postnatal age (Galet et al 1976). …”

The Influence of Dietary Factors on the Vitamin E Requirements of the Low Birthweight Infant

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Protective effect of exogenous transferrin against hyperoxia: A study on premature rabbits

“…In the newborn, particularly in the preterm, plasma concentrations of TF and ceruloplasmin are lower than in older individuals. 8,9 Shortly after birth, premature newborns have a very high iron satura-tion of TF, in part as a consequence of lack of utilization of extracellular iron for erythropoiesis, 8 of complications (hemorrhages, hemolysis), and of iatrogenic causes (blood transfusions). 10 High iron saturation of TF increases the likelihood that an excess of iron becomes available for the redox reactions as a transient metal.…”