Concentrations of granulocyte colony-stimulating factor in human milk after <i>in vitro</i> simulations of digestion

作     者：Calhoun, DA Lunoe, M Du, Y Staba, SL Christensen, RD 

作者机构：Univ Florida Div Neonatol Dept Pediat Coll Med Gainesville FL 32610 USA 

出 版 物：《PEDIATRIC RESEARCH》 (儿科研究)

年 卷 期：1999年第46卷第6期

页      面：767-771页

核心收录：

学科分类：1002[医学-临床医学] 100202[医学-儿科学] 10[医学] 

基　　金：National Heart, Lung, and Blood Institute, NHLBI, (R01HL044951) National Heart, Lung, and Blood Institute, NHLBI 

主　　题：消化 粒细胞集落刺激因子 重组/药理学 粒细胞集落刺激因子/代谢 乳 人/代谢 人类 

摘      要：Human milk contains proteins that survive digestion in the neonatal gastrointestinal tract. Our group and others have reported that granulocyte colony-stimulating factor (G-CSF), a hematopoietic cytokine that influences neutrophil proliferation and differentiation, is present in human milk. We also reported that specific receptors for G-CSF are expressed on the villous enterocytes of neonates. However, the physiologic role of milk-borne G-CSF is not known. Thus, we sought to evaluate the capacity of human milk to protect G-CSF against proteolytic degradation after exposure to gastric secretions obtained from preterm (PT) and term (T) neonates at pH concentrations of 3.2, 5.8, and 7.4. Specifically, we examined degradation of 1) endogenous G-CSF in PT (n = 15) and T (n = 15) human milk;2) recombinant human G-CSF (rhG-CSF) added to a protein-free buffer (n = 10, 5 PT and 5 T);and 3) rhG-CSF added to human milk (n = 12, 6 PT and 6 T), various commercially prepared infant formulas tit = 15), and cow s milli (n = 5). Endogenous G-CSF and rhG-CSF added to human milk resisted degradation at 1 and 2 h. However, when rhG-CSF was added to commercial formulas, 95% was degraded at 1 and 2 h at each pH level. Similarly, approximately 60% of rhG-CSF added to cow s milk was degraded at 1 and 2 h. We conclude that I) endogenous G-CSF and rhG-CSF added to human milk are protected from degradation after exposure to gastric secretions at physiologic pH levels, 2) rhG-CSF added to infant formulas is not protected from degradation, and 3) it is likely that the G-CSF present in human milk is biologically available to the neonate.