Changes in Proteases, Antiproteases, and Bioactive Proteins From Mother's Breast Milk to the Premature Infant Stomach
Changes in Proteases, Antiproteases, and Bioactive Proteins From Mother's Breast Milk to the Premature Infant Stomach
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DOI：
10.1097/mpg.0000000000001719
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发表时间：
2018-02-01
影响因子：
2.9
通讯作者：
Dallas, David C.
中科院分区：
文献类型：
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作者：
Demers-Mathieu, Veronique;Nielsen, Soren Drud;Dallas, David C.
目的：我们以前的研究表明，人乳蛋白酶开始在乳腺中水解蛋白质，并在足月婴儿的胃中继续水解。没有研究测量母乳喂养后早产儿胃吸出物中的牛奶蛋白酶和胃蛋白酶活性。本研究探讨了人乳蛋白酶和蛋白酶抑制剂的浓度如何变化在早产儿gastroint.Methods：人乳和婴儿胃样本收集了18 preterm交付的母婴对（24-32周胎龄）。在出生后年龄（2-47天）采集配对人乳和胃样本。蛋白酶浓度测定分光光度法或荧光测定法，和蛋白酶抑制剂和生物活性蛋白的浓度测定酶联免疫吸附测定。配对t检验用于比较人乳和胃样品之间的酶、抗蛋白酶和生物活性蛋白。我们的研究表明，尽管早产儿胃中存在人乳蛋白酶，包括羧肽酶B2、激肽释放酶、纤溶酶、组织蛋白酶D、弹性蛋白酶、凝血酶和胞浆氨肽酶，只有纤溶酶和组织蛋白酶D可以在胃pH下主动水解蛋白质。连接的免疫吸附试验和肽组学证据表明，所有的乳抗蛋白酶以及乳铁蛋白和免疫球蛋白A都被部分消化，结论：大多数母乳蛋白酶是活跃的牛奶，但不是在早产儿胃的pH值。只有组织蛋白酶D和纤溶酶有潜力继续降解乳蛋白在早产儿胃。
Objective: Our previous studies suggested that human milk proteases begin to hydrolyze proteins in the mammary gland and continue within the term infant' stomach. No research has measured milk protease and pepsin activity in the gastric aspirates of preterm infants after human milk feeding. This study investigated how the concentrations of human milk proteases and protease inhibitors changed in the premature infant stomach.Methods: Human milk and infant gastric samples were collected from 18 preterm-delivering mother-infant pairs (24-32 week gestational age). Paired human milk and gastric samples were collected across postnatal age (2-47 days). Protease concentrations were determined by spectrophotometric or fluorometric assays, and the concentrations of protease inhibitors and bioactive proteins were determined by enzyme-linked immunosorbent assay. Paired t tests were applied to compare enzymes, antiproteases, and bioactive proteins between human milk and gastric samples.Results: Our study reveals that although human milk proteases, including carboxypeptidase B2, kallikrein, plasmin, cathepsin D, elastase, thrombin, and cytosol aminopeptidase, are present in the preterm infant stomach, only plasmin and cathepsin D can actively hydrolyze proteins at gastric pH. Enzyme-linked immunosorbent assay and peptidomic evidence suggest that all milk antiproteases as well as lactoferrin and immunoglobulin A are partially digested in the preterm stomach.Conclusions: Most human milk proteases are active in milk but not at preterm infant gastric pH. Only cathepsin D and plasmin have potential to continue degrading milk proteins within the preterm infant stomach.