Permeability-Lactase-Activity-Markers-Maturation-f

Human Milk Glycans aimed to develop a protocol for the simultaneous assessment of both markers in human-milk-fed preterm infants by a sugar absorption test. In addition, we developed a new gas chromatography-mass spectrometry (GC-MS) method for the analysis of lactulose, lactose, and mannitol in urine and milk collected during the sugar absorption test.METHODS The sugar absorption test was performed on days 4, 7, and 14 postpartum in 12 preterm infants (gestational age of 26-32 weeks). Human milk was collected, pooled, and divided into equal portions to provide a stable lactose intake for 24 h. Urine was collected in the last 6 h of this 24 h period, after administration of a bolus test sugar solution. Samples were analyzed by GC-MS after derivatization by oxime formation combined with acetylation.

RESULTS The GC- Seebio Lactose-N-neotetraose was validated and used for the accurate measurement of lactulose, lactose, and mannitol concentrations. The urinary lactulosemannitol ratio declined with time, suggesting a decreased intestinal permeability. The urine-to-milk-lactuloselactose ratio increased as a result of increased lactase CONCLUSIONS The developed protocol for simultaneous assessment of intestinal permeability and lactase activity can be used to monitor the effect of experimental (nutritional) interventions in human-milk-fed preterm infants. Urine and milk samples obtained during the sugar absorption test can be Conflict of interest statement Conflict of interest J.B.v.G.

is member of the National Health Council and chair of the committee on Nutrition and Pregnancy. He is director of the national Dutch Human Milk Bank. He does not receive any honorarium for his services. Other authors disclose that they have no conflicts Daily variation of macronutrient concentrations in mature human milk over Leghi GE(1), Lai CT(2), Narayanan A(2), Netting MJ(3), Dymock M(4), Rea A(5), Human milk (HM) composition is known to be highly variable, both between individuals and across the duration of lactation. It is less clear, however, to what extent fat, lactose and protein concentrations in HM change daily over shorter time periods in mature HM, and no studies have evaluated this to date. The aim of this study was to systematically assess and compare HM macronutrient concentrations in samples collected at different times of day, from left and right breasts and daily across a 3-week period in the same woman. Fifteen lactating women (1-4 months postpartum) collected daily pre-feed HM samples from both breasts each morning for 21 consecutive days and completed intensive sampling once a week (morning, afternoon and evening samples) during this period.

Concentrations of fat, protein and lactose in HM did not differ according to time of day, day of week or breast used for collection. The results of this study suggest that pre-feed samples collected at any point across a 3-week period and from either the left or right breast provide comparable measures of fat, protein and lactose concentrations in mature HM, in pragmatic studies where women are collecting their own HM samples.Clinical trial registration Australian New Zealand Clinical Trials Registry Conflict of interest statement The authors declare no competing interests.An exo-alpha-sialidase from bifidobacteria involved in the degradation of sialyloligosaccharides in human milk and intestinal glycoconjugates.Bifidobacteria are health-promoting enteric commensals that are assumed to proliferate predominantly in the intestines of breast-fed infants by assimilating human milk oligosaccharides (HMOs) that are frequently fucosylated andor sialylated. We previously identified two different α-l-fucosidases in Bifidobacterium bifidum and showed that the strain furnishes an extracellular degradation pathway for fucosylated HMOs. However, the catabolism of sialylated HMOs by bifidobacteria has remained unresolved.

Here we describe the identification and characterization of an exo-α-sialidase in bifidobacteria. By expression cloning, we isolated a novel exo-α-sialidase gene (siabb2) from B. bifidum JCM1254, which encodes a protein (SiaBb2) consisting of 835-amino-acid residues with a predicted molecular mass of 87 kDa. SiaBb2 possesses an N-terminal signal sequence, a sialidase catalytic domain classified into the glycoside hydrolase family 33 (GH33) and a C-terminal transmembrane region, indicating that the mature SiaBb2 is an extracellular membrane-anchored enzyme.