Accumulation of malto-oligosaccharides in the syncytiotrophoblastic cells of first-trimester human placentas (2025)

Histochemical localization of glucose residues in the human term placenta

Placenta

Glucose residues were revealed by light microscopic and fine structural analysis using hexokinase-gold conjugate. In human term placenta specific staining was detected over the stroma of placental villi. Colloidal gold particles were found over the collagen fibrils and reticular lamina of basal membrane. Syncytiotrophoblast cells, fibroblasts, endothelial cells of fetal capillaries were void of labelling. Nucleated blood cells and thrombocytes inside the lumen of fetal capillaries possessed intense labelling. In the present investigation the process of extracellular glycosylation of collagen was histochemically demonstrated.

High-mannose-type oligosaccharides from human placental arylsulfatase A are core fucosylated as confirmed by MALDI MS

Glycobiology, 2000

Despite numerous studies on arylsulfatase A, the structure of its glycans is not well understood. It has been shown that the concentration of arylsulfatase A increases in the body fluids of patients with some forms of cancer, and the carbohydrate component of arylsulfatase A synthesized in tumor tissues and transformed cells undergoes increased sialylation, phosphorylation and sulfation. To understand the significance of any changes in the glycosylation of arylsulfatase A in cancer, it is important to know the structure of its carbohydrate component in normal tissue. In the present study we have analyzed carbohydrate moieties of human placental arylsylfatase A using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by Western blotting on Immobilon P and on-blot deglycosylation using PNGase F for glycan release. Profiles of N-glycans were obtained by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS). Oligosaccharides were sequenced using specific exoglycosidases, and digestion products were analyzed by MALDI MS and the computer matching of the resulting masses with those derived from a sequence database. Fifty picomoles (6 µg) of arylsulfatase A applied to the gel were sufficient to characterize its oligosaccharide content. The results indicated that human placental arylsulfatase A possesses only high-mannose-type oligosaccharides, of which almost half are core fucosylated. In addition, there was a minor species of high-mannose-type glycan bearing six mannose residues with a core fucose. This structure was not expected since high-mannose-type oligosaccharides basically have not been recognized as a substrate for the α1,6-fucosyltransferase.

Infants Are Exposed to Human Milk Oligosaccharides Already in utero

Frontiers in Pediatrics

Human milk oligosaccharides (HMOs) are complex carbohydrates that are highly abundant in and, in their complexity, unique to human milk. Accumulating evidence indicates that exposure to HMOs in the postnatal period affects immediate as well as long-term infant health and development. However, studies reported in the 1970s showed that HMOs already appear in maternal urine and blood during pregnancy and as early as the first trimester. In this pilot study we aimed to determine whether or not HMOs also appear in amniotic fluid. We enrolled women during pregnancy and collected their urine and amniotic fluid at birth as well as their milk 4 days postpartum. We analyzed the samples by high-performance liquid chromatography (HPLC) and mass spectrometry and identified several HMOs including 2 ′-fucosyllactose, 3-fucosyllactose, difucosyllactose, and 6 ′-sialyllactose to be present in different relative abundancies in all three tissues. This is the first report that HMOs appear in amniotic fluid and that the fetus is already exposed to HMOs in utero, warranting future research to investigate the immediate and long-term implications on fetal and infant health and development.

Preterm Milk Oligosaccharides During the First Month of Lactation

PEDIATRICS, 2011

Characterization of porcine milk oligosaccharides over lactation between primiparous and multiparous female pigs

Scientific Reports, 2018

Milk oligosaccharides (MOs) are complex carbohydrates with multifunctional health benefits for the neonate. Poor reproductive performance in primiparous gilts limits their productivity. Changes in the structure and abundance of porcine MO (PMOs) through lactation with parity remains unknown and may explain superior newborn growth in litters from multiparous sows relative to gilts. We report 55 PMOs structures, of which 25 are new (17 sialylated and 8 neutral). Their incidence in gilt and sow colostrum was almost identical (53 vs. 54), but not in transitional milk (48 vs. 53) nor mature milk (41 vs. 47). These PMOs including neutral-, sialyl-and fucosyl-MOs in colostrum were more abundant in the gilt than the sow, but always decreased during lactation. Structural diversity decreased, although fucosylated MO were conserved. In conclusion, high diversity and levels of MO in porcine milk is parity dependent. Given the similarity between porcine and human MO profiles, our findings may help define key roles for MOs as potential dietary additives to improve growth of neonates from first pregnancies in both human and sows. Milk is the most critically important primary source of nutrition for humans and all newborn mammalian species because of its enrichment with proteins, lipids and carbohydrates. Milk oligosaccharides (MOs), both neutral (N-OS) and sialylated (S-OS), are essential constituents in all mammalian milks. The total concentration of MOs in human (HMOs) colostrum is ~20-25 g/L 1 and ~5-20 g/L in mature milk 1,2. Thus, the MOs are the third largest dietary component in milk, exceeded only by the level of lactose (~70 g/L) and lipid (~40 g/L) 3. MOs mediate a myriad of important biological functions required for skeletal growth and maturation, development of the immune and neural organ systems, establishment of gut microbiota and protection against GI diseases in infants 3-5. Mass spectral analyses of mammalian MOs have revealed a plethora of differences in the chemical structures and relative abundance from different mammalian species 6-10 with >200 distinct structures reported 7,8,11,12. This remarkable diversity is hypothesized to provide the structural basis for their multiple biological functions. Based on the continuing improvement in the sensitivity of mass spectral analyses, it is anticipated that an even greater number of unidentified MOs structures, and their cognate biological functions, will be discovered 9,13,14. Consistent with the structural diversity in MOs from mammalian species is the observation that their core structures generally consist of the hexoses, D-glucose (Glc), D-galactose (Gal), N-acetylglucosamine (GlcNAc), L-fucose (Fuc; 6-deoxy-L-galactose) and the nine-carbon acidic sugar, N-acetylneuraminic acid (Neu5Ac; Sia) 6,15,16. Uniquely, however, is the finding of the N-glycolylneuraminic acid (Neu5Gc) as a sialic acid in goat, bovine and several other mammalian MOs 17. This "non-human" sialic acid" is not a natural constituent in HMOs

Identification of N- and O-linked Oligosaccharides in the Human Epididymis

Journal of Histochemistry & Cytochemistry, 1998

The oligosaccharide sequences of glycoconjugates in the human normal epididymis and the nature of linkages were studied with lectin histochemistry. The usual terminal sequences of oligosaccharide side chains in epithelial cell secretions were Neu5Ac2,3Galβ 1,3GalNAc; SO4Galβ1,3GalNAc; and Galβ1,4GlcNAc, and they were mainly found in O-linked glycoproteins. The lectin pattern of mitochondria-rich cells differed from that of principal cells.

Changes in the Composition and Structure of Glycosaminoglycans in the Human Placenta during Development

Pediatric Research, 1973

Glycosaminoglycans (acid mucopolysaccharides) are ubiquitous in their distribution in the body, yet information as to their biologic function is scanty. Studies of their structure and physical properties in solution suggest that they could function as gel nitration and exchange resins in vivo, thereby playing an important role in regulation of the passage of molecules through the ground substance of connective tissue. The glycosaminoglycan(s) (GAG) composition of the human placenta and the molecular structure of specific GAG has been studied by chemical, enzymatic, and physical methods at 12-18 weeks and at 40 weeks gestational age to explore this postulated structure-function relation. The young placenta contained more GAG (222 mg/100 mg dry defatted tissue) than did the term placenta (155 mg/100 g dry defatted tissue). Sulfated GAG comprised 56% of the total GAG in the young placenta versus 74% in the term placenta due to increased concentrations of dermatan sulfate (25% term versus 13% young placenta) and heparan sulfate (22% term versus 15% young placenta). Ghondroitin was a major component in the young placenta and comprised 22% of the total GAG, whereas the term placenta contained only 9%. Both young and term placenta showed similar quantities of hyaluronic acid and chondroitin 4-and 6-sulfates. Ghondroitin sulfate from the young placenta differed from the polymer in the term placenta in that it contained a higher proportion oi unsulfated dissaccharides. Differences were also found in the molecular structure of dermatan sulfate. Hyaluronidase digestion of purified dermatan sulfate from young placenta produced a 50% reduction in average molecular weight compared with a 30% reduction in the molecular weight of dermatan sulfate isolated from term placenta. The smaller molecular weight fragments of dermatan sulfate from young placenta indicate differences in molecular structure due either to the number of glucuronic acid substitutions or to their position in the polymer chain, or to changes in the concentration of hybrid molecules. Speculation The age-related changes in the composition and molecular structure of placental glycosaminoglycans will result in ground substance gels of differing physical properties. This could alter the transport of molecules through placental connective tissue and affect the rate of fetal growth.

Glycans of the early human yolk sac

The Histochemical Journal, 1995

The pattern of glycan distribution in the early human yolk sac has been investigated using a panel of lectins. Two 6-week and one 8-week human yolk sacs, and one 8-week fetal liver from live, ectopic pregnancies were fixed and embedded in epoxy resin. Lectin histochemistry was carried out on sections of these tissues using 23 biotinylated lectins and an avidin-biotin peroxidase revealing system. Mesothelial surfaces expressed most subsets of N-glycans (other than high mannose types), N-acetyl-lactosamine, sialic acid, and c~l,6-N-acetylgalactosamine. Endodermal surface and lateral membranes resembled those of mesothelium, but showed a preponderance of c~2,6-sialyl residues. Most intracellular granules contained N-glycan. There was a marked heterogeneity of granules in the endodermal cells, with different subsets varying in both staining and positional characteristics. The mesenchymal matrix bound most of the lectins used in the study, and expressed fucosyl residues which were also detected in the endothelium. Fetal liver parenchyma showed very similar staining patterns to those seen in the endoderm except for the distribution of N-acetylglucosamine, which was sparse. Despite some common features, each germ cell layer had a distinct 'glycotype', with some saccharides showing extreme topographical restriction.

Oligosaccharides in feces of breast- and formula-fed babies

Carbohydrate Research, 2011

So far, little is known on the fate of oligosaccharides in the colon of breast-and formula-fed babies. Using capillary electrophoresis with laser induced fluorescence detector coupled to a mass spectrometer (CE-LIF-MS n), we studied the fecal oligosaccharide profiles of 27 two-month-old breast-, formula-and mixed-fed preterm babies. The interpretation of the complex oligosaccharide profiles was facilitated by beforehand clustering the CE-LIF data points by agglomerative hierarchical clustering (AHC). In the feces of breast-fed babies, characteristic human milk oligosaccharide (HMO) profiles, showing genetic fingerprints known for human milk of secretors and non-secretors, were recognized. Alternatively, advanced degradation and bioconversion of HMOs, resulting in an accumulation of acidic HMOs or HMO bioconversion products was observed. Independent of the prebiotic supplementation of the formula with galactooligosaccharides (GOS) at the level used, similar oligosaccharide profiles of low peak abundance were obtained for formula-fed babies. Feeding influences the presence of diet-related oligosaccharides in baby feces and gastrointestinal adaptation plays an important role herein. Four fecal oligosaccharides, characterized as HexNAc-Hex-Hex, Hex-[Fuc]-HexNAc-Hex, HexNAc-[Fuc]-Hex-Hex and HexNAc-[Fuc]-Hex-HexNAc-Hex-Hex, highlighted an active gastrointestinal metabolization of the feeding-related oligosaccharides. Their presence was linked to the gastrointestinal mucus layer and the blood-group determinant oligosaccharides therein, which are characteristic for the host's genotype.

Variation of human milk oligosaccharides in relation to milk groups and lactational periods

British Journal of Nutrition, 2010

Human milk oligosaccharides, representing the third largest fraction of human milk, have been assigned important protective functions for newborns acting as bifidogenic substrates or as inhibitory agents towards pathogens. Using high-pH anion-exchange chromatography and an enzyme test kit, twenty oligosaccharides and lactose were determined in milk samples of German women from days 3 to 90 postpartum. Twenty-two secretor mothers with Lewis blood group Le(a 2 b þ ) synthesised all twenty oligosaccharides, and could be assigned to milk group 1. Five non-secretor mothers (Le(a þ b 2 )) produced all oligosaccharides with the exception of a1,2-fucosylated compounds (milk group 2), whereas three secretor mothers with blood type Le(a 2 b 2 ) lacked a1,4-fucosyloligosaccharides, corresponding to milk group 3. Secretor women of milk groups 1 and 3 synthesised significantly higher amounts of total neutral oligosaccharides and of several total core structures (e.g. lacto-N-tetraose) than non-secretor women. Generally, these oligosaccharides significantly decrease during the first 3 months postpartum. By comparing fucosyloligosaccharides within and among the three milk groups, insight into their biosynthesis could be gained. Six acidic oligosaccharides without fucose residues were detected in milk samples of all mothers. Regression analysis confirmed that total acidic oligosaccharides declined threefold during the study period. Milk samples corresponding to the three milk groups exhibited significant qualitative and quantitative differences during the first 3 months of lactation. It can be assumed that particularly milk of non-secretor women (milk group 2) exerts a modified biological protection in the babies in comparison with milks of secretors (groups 1 and 3).