Goldblum R M, Schanler R J, Garza C, Goldman A S
Department of Pediatrics, University of Texas Medical Branch, Galveston 77550.
Pediatr Res. 1989 Feb;25(2):184-8. doi: 10.1203/00006450-198902000-00021.
The effects of fortified human milk feedings on the urinary excretion of lactoferrin, lysozyme, secretory component, IgA, and secretory IgA antibodies to Escherichia coli O antigens were investigated in very low birth wt infants. Infants were maintained on either a human milk or a cow's milk preparation. The amounts of each immune factor that were ingested and excreted were quantified during balance studies conducted at 2.5 and 5 wk of age. Serum levels of these immune factors were similar in both feeding groups. The urinary excretion of all factors except lysozyme was 7- to 150-fold greater in infants fed human milk than in those fed cow's milk formula. IgA was the only factor for which the amount of the factor excreted correlated with the amount ingested. Fragments as well as whole molecules of lactoferrin were found in the urine of the infants fed human milk, but the molecular sizes of the excreted proteins exceeded those normally filtered by the kidneys. Therefore, the genesis of the enhanced levels of host defense factors in the urine of infants fed human milk is not clear. Gastrointestinal absorption and subsequent renal excretion as well as enhanced production of immune factors in the infant's urinary tract are possible explanations.
研究了强化人乳喂养对极低出生体重儿乳铁蛋白、溶菌酶、分泌成分、IgA以及针对大肠杆菌O抗原的分泌型IgA抗体尿排泄的影响。婴儿分别采用人乳或牛乳制剂喂养。在2.5周和5周龄时进行平衡研究，对摄入和排泄的每种免疫因子的量进行定量。两组喂养婴儿的这些免疫因子血清水平相似。除溶菌酶外，人乳喂养婴儿的所有因子尿排泄量比牛乳配方奶喂养婴儿高7至150倍。IgA是唯一排泄量与摄入量相关的因子。在人乳喂养婴儿的尿液中发现了乳铁蛋白的片段以及完整分子，但排泄蛋白的分子大小超过了肾脏正常滤过的大小。因此，人乳喂养婴儿尿液中宿主防御因子水平升高的原因尚不清楚。胃肠道吸收及随后的肾脏排泄以及婴儿尿路中免疫因子产生增加都是可能的解释。
