Jantscher-Krenn E, Bode L
Division of Neonatology and Division of Gastroenterology and Nutrition, Department of Pediatrics, University of California, San Diego, San Diego, CA, USA.
Minerva Pediatr. 2012 Feb;64(1):83-99.
Human milk oligosaccharides (HMO), unconjugated complex carbohydrates that are highly abundant in human milk but not in infant formula, have recently received much attention due to their potential benefits for the breast-fed neonate. While it is becoming evident that HMO structure determines their specific function, understanding the metabolic fate of ingested HMO is key in assessing their biological roles. Remarkably little is known about how, when and where they are metabolized. HMO have long been regarded as metabolically "inert" to the host, as significant amounts are excreted with the fe-ces. HMO reach the colon intact where their prebiotic effects promote healthy gut colonization. HMO can also function as soluble decoy receptors and block adhesion of microbial pathogens to epithelial surfaces. Local effects at the mucosal lining include differential cell responses or modulation of the innate immune system. A small percentage of HMO is believed to be absorbed intact in the small intestine and later excreted with the urine, which opens speculations on possible systemic effects, e.g. in the immune system or in the context of neuronal development. Oligosaccharides currently added to infant formula are structurally different from HMO and therefore most likely not functionally equivalent. Selected "authentic" HMO might soon become available for the supplementation of infant formula, but additional preclinical and clinical studies are required to demonstrate efficacy. This review provides an overview about the structural and functional properties of HMO with emphasis on recent findings in metabolism studies.
人乳寡糖（HMO）是一类未结合的复合碳水化合物，在人乳中含量极高，但在婴儿配方奶粉中却不存在。由于其对母乳喂养新生儿具有潜在益处，近来备受关注。虽然越来越明显的是HMO的结构决定其特定功能，但了解摄入的HMO的代谢命运是评估其生物学作用的关键。然而，对于它们如何、何时以及在何处进行代谢，人们所知甚少。长期以来，HMO一直被认为对宿主在代谢上是“惰性的”，因为大量HMO会随粪便排出。HMO完整地到达结肠，在那里它们的益生元效应促进健康的肠道定植。HMO还可以作为可溶性诱饵受体，阻止微生物病原体粘附到上皮表面。在粘膜内衬的局部作用包括不同的细胞反应或对先天免疫系统的调节。据信一小部分HMO会在小肠中完整吸收，随后随尿液排出，这引发了关于可能的全身效应的猜测，例如在免疫系统或神经元发育方面。目前添加到婴儿配方奶粉中的寡糖在结构上与HMO不同，因此很可能在功能上不等同。选定的“正宗”HMO可能很快可用于补充婴儿配方奶粉，但需要更多的临床前和临床研究来证明其功效。本综述概述了HMO的结构和功能特性，重点介绍了代谢研究中的最新发现。
