Enhanced Fecal Excretion of Selected Immune Factors in Very Low Birth Weight Infants Fed Fortified Human Milk

Abstract

SIgA, secretory IgA EID, electroimmunodiffusion ELISA, enzyme-linked immunosorbent assayThe decision to feed human milk to VLBW infants often is based on the potential enhancement of host defense. Two approaches have been used in the few studies d~signed to e.valuate the protection afforded by feeding human milk to these mfants: 1) assessment of morbidity and 2) the J?easuremen~of the concentrations of specific immune factors m serum, saliva, and feces of infants fed either human milk or cow's milk-based formulas (1-4). Most epidemiologic studies of morbidity in fullterm infants usually have concluded that breast-feeding is protective but interpretations of these reports often have been confo~nded by uncontrolled demographic variables (5). ",:ssessments of morbidity in VLBW infants have focused on sepSIS and necrotizing enterocolitis. No consistent benefits have been reported (6-8). Concentrations of immuno~obulinsin. the serum were similar in both groups or elevated m VLBW mfants fed cow's milk preparations (9-11).The effects of human milk feeding on fecal excretion of lactoferrin, lysozyme, and SIgA have been reporte~(~-3). Fecal levels of these selected immune factors are greater m mfants fed human milk than in those fed a formula (1-3). In that regard, these selected factors also resist proteolytic digestion (12, 13). These observations suggest that the factors remain intact throughout the infant's gastrointestinal tract. The few studies of immune factors in the feces of VLBW infants, however, have been of short duration and have not been designed to evaluate the effects of the quantity of immune factors fed, variations in nutrient intakes that would influence growth and maturation (1, 2), or intrinsic differences in the characte~stics ofth~population studied such as gastrointestinal absorptIve capaCIty. Furthermore the impact of augmented levels of lactoferrin, lysozyme, and SIgA in milk obtained from women delivering. prema~u~ely has not been considered in the design of most published climcal evaluations (14, 15). Ideally, a study of the effects of human milk on premature infants should be carried out wit~breast-fed infants. This study condition is precluded in VLBW mfants because of their difficulties in suckling and their nutritional needs that may not be met by the nutrient concentrations of human milk (16). " Our investigations of the effects of feedmg human mIlk to VLBW infants began with detailed assessments of the levels and stability of selected nutritional and immune factors during the collection, storage, heat processing, and fractionation of human milk (17-20). A protocol to fortify human milk was developed 711 Abbreviations ABSTRACT. The amounts of lactoferrin, lysozyme, total IgA, secretory IgA (SIgA), and specific SIgA antibodies to a pool of Escherichia coli 0 antigens were measured lD 96-h collections of feces obtained from 28 very low birth weight infants, 28-30 wk of gestation, studied at 2.5 and 6 wk of age. Eighteen of these infants were fed their mot~ers' milk fortified with fractions ...

Lactoferrin in the Preterm Infants' Diet Attenuates Iron-Induced Oxidation Products

“…Dietary Lf is minimally hydrolyzed in the preterm infant's stomach (48), with some Lf persisting during transit through the bowel (49). The presence of Lf-specific receptors in the human intestine (50) suggests a physiologic role for Lf and makes it likely that Lf supplementation of formula would be tolerated.…”

Human Milk Feeding Enhances the Urinary Excretion of Immunologic Factors in Low Birth Weight Infants

“…It was previously ascertained that this preparation met reasonable microbiologic standards (26), that the concentrations of many of the immunologic factors in the preparation were maintained after brief high temperature treatment (26), and that its use resulted in growth rates similar to those observed during intrauterine life (27). We have also studied its effects on the fecal excretion of selected immunologic factors in VLBW infants (28). The fecal excretion of human lactoferrin, lysozyme, SIgA, and SIgA antibodies to a pool of Escherichia coli somatic ( 0 ) antigens was greater in infants fed fortified human milk than in those fed a cow's milk formula.…”

“…Although no correlations were noted between the ingested amounts of lactofenin, lysozyme, and SIgA, the excreted amounts of these factors were positively correlated with each other. That observation suggested that unidentified factors in milk may enhance the coordinated production of certain mucosal immune factors by the infant (28).To investigate further the possible effects of this human milk preparation on the mucosal immunity of premature infants, we measured the excretion of immunologic factors in the urine of these VLBW infants (27,28). Urine was chosen because that external secretion is produced in part by epithelial cells that are not in direct contact with ingested milk, and because it can be collected continuously during test balance periods.…”

Molecular Forms of Lactoferrin in Stool and Urine from Infants Fed Human Milk

“…The molecular forms of lactoferrin (LF) were of the infant (3)(4)(5)(6)(7)(8)(9)(10)(11)(12). Recent studies demonstrate that the urinary examined in stools and urine collected at 2.5 or 5 wk of excretion of IgA (1 1, 12), total secretory component (12), and age from very low birth wt infants fed either a cow's milk LF (12) was greater in human milk as compared to cow's milkformula or a fortified human milk preparation.…”