Sialic acid in human milk and infant formulas in China: concentration, distribution and type

This study compared the concentrations, types and distributions of sialic acid (SA) in human milk at different stages of the postnatal period with those in a range of infant formulas. Breast milk from mothers of healthy, full-term and exclusively breastfed infants was collected on the 2nd (n 246), 7th (n 135), 30th (n 85) and 90th (n 48) day after birth. The SA profiles of human milk, including their distribution, were analysed and compared with twenty-four different infant formulas. Outcome of this observational study was the result of natural exposure. Only SA of type Neu5Ac was detected in human milk. Total SA concentrations were highest in colostrum and reduced significantly over the next 3 months. Approximately 68·7–76·1 % of all SA in human milk were bound to oligosaccharides. Two types of SA, Neu5Ac and Neu5Gc, have been detected in infant formulas. Most SA was present in infant formulas combined with protein. Breastfed infants could receive more SA than formula-fed infants with the same energy intake. Overall, human milk is a preferable source of SA than infant formulas in terms of total SA content, dynamics, distribution and type. These SA profiles in the natural state are worth to be considered by the production of formulas because they may have a great effect on infant nutrition and development.

Innovative direct introduction-ion mobility-mass spectrometry (DI-IM-MS) approach for fast and robust isomer-specific quantification in a complex matrix: Application to 2'-fucosyllactose (2'-FL) in breast milk

Identification and specific quantification of isomers in a complex biological matrix by mass spectrometry alone is not an easy task due to their identical chemical formula and therefore their same mass-to-charge ratio (m/z). Here, the potential of direct introduction combined with ion mobility-mass spectrometry (DI-IM-MS) for rapid quantification of isomers as human milk oligosaccharides (HMOs) was investigated. Differences in HMO profiles between various analyzed breast milk samples were highlighted using the single ion mobility monitoring (SIM2) acquisition for high ion mobility resolution detection. Furthermore, the Se+ (secretor) or Se- (non-secretor) phenotype could be assigned to breast milk samples studied based on their HMO contents, especially on the response of 2'-fucosyllactose (2'-FL) and lacto-N-fucopentaose I (LNFP I). The possibility of quantifying a specific isomer in breast milk by DI-IM-MS was also investigated. The standard addition method allowed the determination of the 2'-FL despite the presence of other oligosaccharides, including 3-fucosyllactose (3-FL) isomer in breast milk. This proof-of-concept study demonstrated the high potential of such an approach for the rapid and convenient quantification of isomers in complex mixtures.

Spaceflight impacts xyloglucan oligosaccharide abundance in Arabidopsis thaliana root cell walls

Over the course of more than a decade, space biology investigations have consistently indicated that cell wall remodeling occurs in a variety of spaceflight-grown plants. Here, we describe a mass spectrometric method to study the fundamental composition of xyloglucan, the most abundant hemicellulose in dicot cell walls, in space-grown plants. Four representative Arabidopsis root samples, from a previously conducted spaceflight experiment - Advanced Plant EXperiment - 04 (APEX-04), were used to investigate changes in xyloglucan oligosaccharides abundances in spaceflight-grown plants compared to ground controls. In situ localized enzymatic digestions and surface sampling mass spectrometry analysis provided spatial resolution of the changes in xyloglucan oligosaccharides abundances. Overall, the results showed that oligosaccharide XXLG/XLXG and XXFG branching patterns were more abundant in the lateral roots of spaceflight-grown plants, while XXXG, XLFG, and XLFG/XLFG were more abundant in the lateral roots of ground control plants. In the primary roots, XXFG had a higher abundance in ground controls than in spaceflight plants. This methodology of analyzing the basic components of the cell wall in this paper highlights two important findings. First, that are differences in the composition of xyloglucan oligosaccharides in spaceflight root cell walls compared to ground controls and, second, most of these differences are observed in the lateral roots. Thus, the methodology described in this paper provides insights into spaceflight cell wall modifications for future investigations.

Isolation of Human Milk Difucosyl Nona- and Decasaccharides by Ultrahigh-Temperature Preparative PGC-HPLC and Identification of Novel Difucosylated Heptaose and Octaose Backbones by Negative-Ion ESI-MSn

Despite their many important physiological functions, past work on the diverse sequences of human milk oligosaccharides (HMOs) has been focused mainly on the highly abundant HMOs with a relatively low degree of polymerization (DP) due to the lack of efficient methods for separation/purification and high-sensitivity sequencing of large-sized HMOs with DP ≥ 10. Here we established an ultrahigh-temperature preparative HPLC based on a porous graphitized carbon column at up to 145 °C to overcome the anomeric α/β splitting problem and developed further the negative-ion ESI-CID-MS/MS into multistage MSn using a combined product-ion scanning of singly charged molecular ion and doubly charged fragment ion of the branching Gal and adjacent GlcNAc residues. The separation and sequencing method allows efficient separation of a neutral fraction with DP ≥ 10 into 70 components, among which 17 isomeric difucosylated nona- and decasaccharides were further purified and sequenced. As a result, novel branched difucosyl heptaose and octaose backbones were unambiguously identified in addition to the conventional linear and branched octaose backbones. The novel structures of difucosylated DF-novo-heptaose, DF-novo-LNO I, and DF-novo-LNnO I were corroborated by NMR. The various fucose-containing Lewis epitopes identified on different backbones were confirmed by oligosaccharide microarray analysis.

Microbiota from human infants consuming secretors or non-secretors mothers' milk impacts the gut and immune system in mice

Maternal secretor status is one of the determinants of human milk oligosaccharides (HMOs) composition, which, in turn, influences the gut microbiota composition of infants. To understand if this change in gut microbiota impacts immune cell composition, intestinal morphology, and gene expression, 21-day-old germ-free C57BL/6 mice were transplanted with fecal microbiota from infants whose mothers were either secretors (SMM) or non-secretors (NSM) or from infants consuming dairy-based formula (MFM). For each group, one set of mice was supplemented with HMOs. HMO supplementation did not significantly impact the microbiota diversity; however, SMM mice had a higher abundance of genus Bacteroides, Bifidobacterium, and Blautia, whereas, in the NSM group, there was a higher abundance of Akkermansia, Enterocloster, and Klebsiella. In MFM, gut microbiota was represented mainly by Parabacteroides, Ruminococcaceae_unclassified, and Clostrodium_sensu_stricto. In mesenteric lymph node, Foxp3+ T cells and innate lymphoid cells type 2 were increased in MFM mice supplemented with HMOs, while in the spleen, they were increased in SMM + HMOs mice. Similarly, serum immunoglobulin A was also elevated in MFM + HMOs group. Distinct global gene expression of the gut was observed in each microbiota group, which was enhanced with HMOs supplementation. Overall, our data show that distinct infant gut microbiota due to maternal secretor status or consumption of dairy-based formula and HMO supplementation impacts immune cell composition, antibody response, and intestinal gene expression in a mouse model.

IMPORTANCE

Early life factors like neonatal diet modulate gut microbiota, which is important for the optimal gut and immune function. One such factor, human milk oligosaccharides (HMOs), the composition of which is determined by maternal secretor status, has a profound effect on infant gut microbiota. However, how the infant gut microbiota composition determined by maternal secretor status or consumption of infant formula devoid of HMOs impacts infant intestinal ammorphology, gene expression, and immune signature is not well explored. This study provides insights into the differential establishment of infant microbiota derived from infants fed by secretor or non-secretor mothers milk or those consuming infant formula and demonstrates that the secretor status of mothers promotes Bifidobacteria and Bacteroides sps. establishment. This study also shows that supplementation of pooled HMOs in mice changed immune cell composition in the spleen and mesenteric lymph nodes and immunoglobulins in circulation. Hence, this study highlights that maternal secretor status has a role in infant gut microbiota composition, and this, in turn, can impact host gut and immune system.

Air pollution exposure may impact the composition of human milk oligosaccharides

Human milk oligosaccharides (HMOs) impact neonate immunity and health outcomes. However, the environmental factors influencing HMO composition remain understudied. This study examined the associations between ambient air pollutant (AAP) exposure and HMOs at 1-month postpartum. Human milk samples were collected at 1-month postpartum (n = 185). AAP (PM2.5, PM10, NO2) exposure included the 9-month pregnancy period through 1-month postpartum. Associations between AAP with (1) HMO diversity, (2) the sum of sialylated and fucosylated HMOs, (3) 6 a priori HMOs linked with infant health, and (4) all HMOs were examined using multivariable linear regression and principal component analysis (PCA). Exposure to AAP was associated with lower HMO diversity. PM2.5 and PM10 exposure was positively associated with the HMO 3-fucosyllactose (3FL); PM2.5 exposure was positively associated with the sum of total HMOs, sum of fucosylated HMOs, and the HMO 2'-fucosyllactose (2'FL). PCA indicated the PM2.5, PM10, and NO2 exposures were associated with HMO profiles. Individual models indicated that AAP exposure was associated with five additional HMOs (LNFP I, LNFP II, DFLNT, LNH). This is the first study to demonstrate associations between AAP and breast milk HMOs. Future longitudinal studies will help determine the long-term impact of AAP on human milk composition.

Genome-scale metabolic modeling of the human milk oligosaccharide utilization by Bifidobacterium longum subsp. infantis

Bifidobacterium longum subsp. infantis is a representative and dominant species in the infant gut and is considered a beneficial microbe. This organism displays multiple adaptations to thrive in the infant gut, regarded as a model for human milk oligosaccharides (HMOs) utilization. These carbohydrates are abundant in breast milk and include different molecules based on lactose. They contain fucose, sialic acid, and N-acetylglucosamine. Bifidobacterium metabolism is complex, and a systems view of relevant metabolic pathways and exchange metabolites during HMO consumption is missing. To address this limitation, a refined genome-scale network reconstruction of this bacterium is presented using a previous reconstruction of B. infantis ATCC 15967 as a template. The latter was expanded based on an extensive revision of genome annotations, current literature, and transcriptomic data integration. The metabolic reconstruction (iLR578) accounted for 578 genes, 1,047 reactions, and 924 metabolites. Starting from this reconstruction, we built context-specific genome-scale metabolic models using RNA-seq data from cultures growing in lactose and three HMOs. The models revealed notable differences in HMO metabolism depending on the functional characteristics of the substrates. Particularly, fucosyl-lactose showed a divergent metabolism due to a fucose moiety. High yields of lactate and acetate were predicted under growth rate maximization in all conditions, whereas formate, ethanol, and 1,2-propanediol were substantially lower. Similar results were also obtained under near-optimal growth on each substrate when varying the empirically observed acetate-to-lactate production ratio. Model predictions displayed reasonable agreement between central carbon metabolism fluxes and expression data across all conditions. Flux coupling analysis revealed additional connections between succinate exchange and arginine and sulfate metabolism and a strong coupling between central carbon reactions and adenine metabolism. More importantly, specific networks of coupled reactions under each carbon source were derived and analyzed. Overall, the presented network reconstruction constitutes a valuable platform for probing the metabolism of this prominent infant gut bifidobacteria.IMPORTANCEThis work presents a detailed reconstruction of the metabolism of Bifidobacterium longum subsp. infantis, a prominent member of the infant gut microbiome, providing a systems view of its metabolism of human milk oligosaccharides.

More than nutrition: Therapeutic potential and mechanism of human milk oligosaccharides against necrotizing enterocolitis

Human milk is the most valuable source of nutrition for infants. The structure and function of human milk oligosaccharides (HMOs), which are key components of human milk, have long been attracting particular research interest. Several recent studies have found HMOs to be efficacious in the prevention and treatment of necrotizing enterocolitis (NEC). Additionally, they could be developed in the future as non-invasive predictive markers for NEC. Based on previous findings and the well-defined functions of HMOs, we summarize potential protective mechanisms of HMOs against neonatal NEC, which include: modulating signal receptor function, promoting intestinal epithelial cell proliferation, reducing apoptosis, restoring intestinal blood perfusion, regulating microbial prosperity, and alleviating intestinal inflammation. HMOs supplementation has been demonstrated to be protective against NEC in both animal studies and clinical observations. This calls for mass production and use of HMOs in infant formula, necessitating more research into the safety of industrially produced HMOs and the appropriate dosage in infant formula.

Simulated digestions of free oligosaccharides and mucin-type O-glycans reveal a potential role for Clostridium perfringens

The development of a stable human gut microbiota occurs within the first year of life. Many open questions remain about how microfloral species are influenced by the composition of milk, in particular its content of human milk oligosaccharides (HMOs). The objective is to investigate the effect of the human HMO glycome on bacterial symbiosis and competition, based on the glycoside hydrolase (GH) enzyme activities known to be present in microbial species. We extracted from UniProt a list of all bacterial species catalysing glycoside hydrolase activities (EC 3.2.1.-), cross-referencing with the BRENDA database, and obtained a set of taxonomic lineages and CAZy family data. A set of 13 documented enzyme activities was selected and modelled within an enzyme simulator according to a method described previously in the context of biosynthesis. A diverse population of experimentally observed HMOs was fed to the simulator, and the enzymes matching specific bacterial species were recorded, based on their appearance of individual enzymes in the UniProt dataset. Pairs of bacterial species were identified that possessed complementary enzyme profiles enabling the digestion of the HMO glycome, from which potential symbioses could be inferred. Conversely, bacterial species having similar GH enzyme profiles were considered likely to be in competition for the same set of dietary HMOs within the gut of the newborn. We generated a set of putative biodegradative networks from the simulator output, which provides a visualisation of the ability of organisms to digest HMO and mucin-type O-glycans. B. bifidum, B. longum and C. perfringens species were predicted to have the most diverse GH activity and therefore to excel in their ability to digest these substrates. The expected cooperative role of Bifidobacteriales contrasts with the surprising capacities of the pathogen. These findings indicate that potential pathogens may associate in human gut based on their shared glycoside hydrolase digestive apparatus, and which, in the event of colonisation, might result in dysbiosis. The methods described can readily be adapted to other enzyme categories and species as well as being easily fine-tuneable if new degrading enzymes are identified and require inclusion in the model.

Comparative Analysis of Free and Glycoconjugates Oligosaccharide Content in Milk from Different Species

Human milk is important for infant growth, and oligosaccharides are one of its main functional nutrients. To enable a systematic comparison of free oligosaccharide and glycoconjugate content in milk from different species, the phenol-sulfuric acid and resorcinol assays were combined to determine the content. Using real samples, the method revealed that human milk contained the highest amount of total, neutral (9.84 ± 0.31 g/L), and sialylated (3.21 ± 0.11 g/L) free oligosaccharides, followed by goat milk, with neutral (0.135 ± 0.015 g/L) and sialylated (0.192 ± 0.016 g/L) free oligosaccharides and at a distance by bovine and yak milk. The highest total glycoconjugate content was detected in yak milk (0.798 ± 0.011 g/L), followed by human, bovine, and goat milk. These findings suggest that goat milk is the best source of free oligosaccharides in infant formula and functional dairy products and yak milk is the best source of glycoconjugates.

Simple Routes to Stable Isotope-Coded Native Glycans

Understanding the biological role of protein-linked glycans requires the reliable identification of glycans. Isomer separation and characterization often entail mass spectrometric detection preceded by high-performance chromatography on porous graphitic carbon. To this end, stable isotope-labeled glycans have emerged as powerful tools for retention time normalization. Hitherto, such standards were obtained by chemoenzymatic or purely enzymatic methods, which introduce, e.g., 13C-containing N-acetyl groups or galactose into native glycans. Glycan release with anhydrous hydrazine opens another route for heavy isotope introduction via concomitant de-N-acetylation. Here, we describe that de-N-acetylation can also be achieved with hydrazine hydrate, which is a more affordable and less hazardous reagent. Despite the slower reaction rate, complete conversion is achievable in 72 h at 100 °C for glycans with biantennary glycans with or without sialic acids. Shorter incubation times allow for the isolation of intermediate products with a defined degree of free amino groups, facilitating introduction of different numbers of heavy isotopes. Mass encoded glycans obtained by this versatile approach can serve a broad range of applications, e.g., as internal standards for isomer-specific studies of N-glycans, O-glycans, and human milk oligosaccharide by LC-MS on either porous graphitic carbon or─following permethylation─on reversed phase.

Extraction of Mucin from Rodent Feces and Determination of O-Linked Oligosaccharide Chain Equivalent Derived from Fecal Mucin

Since the core protein of mucin in the digesta of the stomach and small intestine, which is less affected by bacteria, remains intact, mucin content can be measured by enzyme-linked immunosorbent assay (ELISA). However, the mucin core protein in bacteria-rich colon digesta and feces is partially hydrolyzed by bacterial enzymes and not fully recognized by mucin antibodies, so mucin cannot be accurately quantified by ELISA. This method quantifies the glycan content linked to the mucin core protein and expresses mucin content in the colon digesta and feces as the equivalent of O-linked oligosaccharide chain. Although mucin glycans are also hydrolyzed by colonic bacteria, this method is a more accurate and simple way to measure mucin content in the digesta of the large intestine and feces than the ELISA method.

Quantitation of bioactive components in infant formulas: Milk oligosaccharides, sialic acids and corticosteroids

Human milk is considered the optimal food for infants with abundant nutrients and bioactive components, which play key roles in infant health and development. Infant formulas represent appropriate substitutes for human milk. There are many brands of infant formula with different ingredient sources and functions on the market. The present study aims to quantify important bioactive components, i.e., milk oligosaccharides (MOS), sialic acids (Sia) and corticosteroids, in different infant formulas and compare these to human milk. In total, 12 different infant formulas available on the Dutch market were analyzed in this study. The concentrations of MOS and Sia were characterized by UHPLC-FLD and LC-MS, while corticosteroids were determined using established UHPLC-MS/MS methods. Among infant formulas, 15 structures of oligosaccharides were identified, of which 2'-Fucosyllactose (2'FL), 3'-Galactosyllactose (3'GL) and 6'-Galactosyllactose (6́'GL) were found in all infant formulas. The oligosaccharide concentrations differed between milk source and brands and were 3-5 times lower than in human milk. All infant formulas contained Sia, N-acetylneuraminic acid (Neu5Ac) was dominant in bovine milk-based formulas, while N-glycolylneuraminic acid (Neu5Gc) was major in goat milk-based formula. All infant formulas contained corticosteroids, yet, at lower concentrations than human milk. Insight in concentrations of bioactive components in infant formula compared to human milk may give direction to dietary advices and/or novel formula design.

Molecular strategies for the utilisation of human milk oligosaccharides by infant gut-associated bacteria

A number of bacterial species are found in high abundance in the faeces of healthy breast-fed infants, an occurrence that is understood to be, at least in part, due to the ability of these bacteria to metabolize human milk oligosaccharides (HMOs). HMOs are the third most abundant component of human milk after lactose and lipids, and represent complex sugars which possess unique structural diversity and are resistant to infant gastrointestinal digestion. Thus, these sugars reach the infant distal intestine intact, thereby serving as a fermentable substrate for specific intestinal microbes, including Firmicutes, Proteobacteria, and especially infant-associated Bifidobacterium spp. which help to shape the infant gut microbiome. Bacteria utilising HMOs are equipped with genes associated with their degradation and a number of carbohydrate-active enzymes known as glycoside hydrolase enzymes have been identified in the infant gut, which supports this hypothesis. The resulting degraded HMOs can also be used as growth substrates for other infant gut bacteria present in a microbe-microbe interaction known as 'cross-feeding'. This review describes the current knowledge on HMO metabolism by particular infant gut-associated bacteria, many of which are currently used as commercial probiotics, including the distinct strategies employed by individual species for HMO utilisation.

The Influence of Early Nutrition on Neurodevelopmental Outcomes in Preterm Infants

Premature infants, given their limited reserves, heightened energy requirements, and susceptibility to nutritional deficits, require specialized care.

AIM

To examine the complex interplay between nutrition and neurodevelopment in premature infants, underscoring the critical need for tailored nutritional approaches to support optimal brain growth and function.

DATA SOURCES

PubMed and MeSH and keywords: preterm, early nutrition, macronutrients, micronutrients, human milk, human milk oligosaccharides, probiotics AND neurodevelopment or neurodevelopment outcomes. Recent articles were selected according to the authors' judgment of their relevance. Specific nutrients, including macro (amino acids, glucose, and lipids) and micronutrients, play an important role in promoting neurodevelopment. Early and aggressive nutrition has shown promise, as has recognizing glucose as the primary energy source for the developing brain. Long-chain polyunsaturated fatty acids, such as DHA, contribute to brain maturation, while the benefits of human milk, human milk oligosaccharides, and probiotics on neurodevelopment via the gut-brain axis are explored. This intricate interplay between the gut microbiota and the central nervous system highlights human milk oligosaccharides' role in early brain maturation.

CONCLUSIONS

Individualized nutritional approaches and comprehensive nutrient strategies are paramount to enhancing neurodevelopment in premature infants, underscoring human milk's potential as the gold standard of nutrition for preterm infants.

Evaluation and Mechanistic Investigation of Human Milk Oligosaccharide against SARS-CoV-2

Four human milk oligosaccharides (HMOs), 3'-sialyllactose (3'-SL), 6'-sialyllactose (6'-SL), 2'-fucosyllactose (2'-FL), and 3-fucosyllactose (3-FL), were assessed for their possible antiviral activity against the SARS-CoV-2 spike receptor binding domain (RBD) in vitro. Among them, only 2'-FL/3-FL exhibited obvious antibinding activity against direct binding and trans-binding in competitive immunocytochemistry and enzyme-linked immunosorbent assays. The antiviral effects of 2'-FL/3-FL were further confirmed by pseudoviral assays with three SARS-Cov-2 mutants, with a stronger inhibition effect of 2'-FL than 3-FL. Then, 2'-FL/3-FL were studied with molecular docking and microscale thermophoresis analysis, showing that the binding sites of 2'-FL on RBD were involved in receptor binding, in addition to a tighter bond between them, thus enabling 2'-FL to be more effective than 3-FL. Moreover, the immunomodulation effect of 2'-FL was preliminary evaluated and confirmed in a human alveolus chip. These results would open up possible applications of 2'-FL for the prevention of SARS-CoV-2 infections by competitive binding inhibition.

Dietary Prebiotic Oligosaccharides and Arachidonate Alter the Fecal Microbiota and Mucosal Lipid Composition of Suckling Pigs

BACKGROUND

Early intestinal development is important to infant vitality, and optimal formula composition can promote gut health.

OBJECTIVES

The objectives were to evaluate the effects of arachidonate (ARA) and/or prebiotic oligosaccharide (PRE) supplementation in formula on the development of the microbial ecosystem and colonic health parameters.

METHODS

Newborn piglets were fed 4 formulas containing ARA [0.5 compared with 2.5% of dietary fatty acids (FAs)] and PRE (0 compared with 8 g/L, containing a 1:1 mixture of galactooligosaccharides and polydextrose) in a 2 x 2 factorial design for 22 d. Fecal samples were collected weekly and analyzed for relative microbial abundance. Intestinal samples were collected on day 22 and analyzed for mucosal FAs, pH, and short-chain FAs (SCFAs).

RESULTS

PRE supplementation significantly increased genera within Bacteroidetes and Firmicutes, including Anaerostipes, Mitsuokella, Prevotella, Clostridium IV, and Bulleidia, and resulted in progressive separation from controls as determined by Principal Coordinates Analysis. Concentrations of SCFA increased from 70.98 to 87.37 mM, with an accompanying reduction in colonic pH. ARA supplementation increased the ARA content of the colonic mucosa from 2.35-5.34% of total FAs. PRE supplementation also altered mucosal FA composition, resulting in increased linoleic acid (11.52-16.33% of total FAs) and ARA (2.35-5.16% of total FAs).

CONCLUSIONS

Prebiotic supplementation during the first 22 d of life altered the gut microbiota of piglets and increased the abundance of specific bacterial genera. These changes correlated with increased SCFA, which may benefit intestinal development. Although dietary ARA did not alter the microbiota, it increased the ARA content of the colonic mucosa, which may support intestinal development and epithelial repair. Prebiotic supplementation also increased unsaturation of FAs in the colonic mucosa. Although the mechanism requires further investigation, it may be related to altered microbial ecology or biohydrogenation of FA.

The Influence of Oligosaccharides when Measuring Lactose and Total Carbohydrates in Human Milk and Comparison of Methods

BACKGROUND

Understanding how human milk impacts growth requires valid analytical methods for quantifying the composition. Lactose, the most abundant constituent in human milk and a predominant source of energy, is often assessed using methods borrowed from the bovine dairy industry. However, the carbohydrate matrices of bovine and human milk are quite different, especially as they relate to human milk oligosaccharides (HMOs), each with a terminal lactose unit that may influence analytical methods.

OBJECTIVES

Our goals were to determine the extent to which HMOs influence common analytical methods for measuring carbohydrates in human milk and to compare common methods for measuring lactose.

METHODS

Two sets of experiments were performed. In the first set, native and HMO-spiked human milk samples (n = 16 each) were assessed and compared using 4 methods: AOAC 2006.06 (based on the Megazyme enzymatic assay), BioVision enzymatic assay, ultraperformance LC with MS, and infrared analysis. In the second set, human milk samples (n = 20) were assessed using 2 methods approved for measuring lactose in bovine milk: AOAC 984.22 that uses high-performance LC and refractive index detection and AOAC 2006.06 prepared using both volume and weighted dilutions.

RESULTS

Native and HMO-spiked samples were not significantly different in lactose using AOAC 2006.06 and ultraperformance LC with MS but were significantly different using BioVision (mean difference = 0.2 g/dL; 95% CI: 0.1, 0.4; P = 0.005). Total carbohydrate measurements assessed using infrared were also higher after HMO spiking (mean difference = 0.4 g/dL; 95% CI: 0.3, 0.6; P < 0.001). Only AOAC methods 984.22 and 2006.06 for measuring lactose were very highly correlated (r > 0.90, P < 0.001).

CONCLUSIONS

AOAC methods 984.22 and 2006.06 are comparable for measuring lactose in human milk and are not influenced by HMOs. HMOs influence other enzymatic methods as well as infrared analysis, which leads to an overestimate of energy values. J Nutr 2023;x:xx.

Human milk oligosaccharides reduce necrotizing enterocolitis-induced neuroinflammation and cognitive impairment in mice

Necrotizing enterocolitis (NEC) is the leading cause of morbidity and mortality in premature infants. One of the most devastating complications of NEC is the development of NEC-induced brain injury, which manifests as impaired cognition that persists beyond infancy and which represents a proinflammatory activation of the gut-brain axis. Given that oral administration of the human milk oligosaccharides (HMOs) 2'-fucosyllactose (2'-FL) and 6'-sialyslactose (6'-SL) significantly reduced intestinal inflammation in mice, we hypothesized that oral administration of these HMOs would reduce NEC-induced brain injury and sought to determine the mechanisms involved. We now show that the administration of either 2'-FL or 6'-SL significantly attenuated NEC-induced brain injury, reversed myelin loss in the corpus callosum and midbrain of newborn mice, and prevented the impaired cognition observed in mice with NEC-induced brain injury. In seeking to define the mechanisms involved, 2'-FL or 6'-SL administration resulted in a restoration of the blood-brain barrier in newborn mice and also had a direct anti-inflammatory effect on the brain as revealed through the study of brain organoids. Metabolites of 2'-FL were detected in the infant mouse brain by nuclear magnetic resonance (NMR), whereas intact 2'-FL was not. Strikingly, the beneficial effects of 2'-FL or 6'-SL against NEC-induced brain injury required the release of the neurotrophic factor brain-derived neurotrophic factor (BDNF), as mice lacking BDNF were not protected by these HMOs from the development of NEC-induced brain injury. Taken in aggregate, these findings reveal that the HMOs 2'-FL and 6'-SL interrupt the gut-brain inflammatory axis and reduce the risk of NEC-induced brain injury.NEW & NOTEWORTHY This study reveals that the administration of human milk oligosaccharides, which are present in human breast milk, can interfere with the proinflammatory gut-brain axis and prevent neuroinflammation in the setting of necrotizing enterocolitis, a major intestinal disorder seen in premature infants.

Age-dependent associations of human milk oligosaccharides with body size and composition up to 4 years of age

BACKGROUND

Human milk oligosaccharides (HMOs) are major components of human milk that may mediate its beneficial effects on infant growth.

OBJECTIVES

To investigate relationships between HMO concentrations in milk at 6 wk postpartum and anthropometry to 4 y of age in human milk-fed infants.

METHODS

Milk samples were collected from 292 mothers at 6 wk (median 6.0 wk; range 3.3, 11.1] postpartum in a longitudinal, population-derived cohort. Of the infants, 171 were exclusively human milk-fed to 3 mo of age and 127 to 6 mo. Concentrations of 19 HMOs were quantified using high-performance liquid chromatography. Maternal secretor status (n = 221 secretors) was determined from 2'-fucosyllactose (2'FL) concentration. We calculated z-scores for child weight, length, head circumference, summed triceps and subscapular skinfold thicknesses, and weight-for-length at 6 wk, 6 mo, 12 mo, and 4 y. We investigated associations of secretor status and each HMO measure with change from birth for each z-score using linear mixed-effects models.

RESULTS

Maternal secretor status was not associated with anthropometric z-scores up to 4 y of age. Several HMOs were associated with z-scores at 6 wk and 6 mo, predominantly within secretor status subgroups. Higher levels of 2'FL were associated with greater weight [β = 0.91 increase in z-score per SD increase log-2'FL, 95% CI (0.17, 1.65)] and length [β = 1.22, (0.25, 2.20)] in children born to secretor mothers, but not body composition measures. Higher lacto-N-tetraose was associated with greater weight [β = 0.22, (0.02, 0.41)] and length (β = 0.30, (0.07, 0.53)] among children born to nonsecretor mothers. Several HMOs were associated with anthropometric measures at 12 mo and 4 y of age.

CONCLUSIONS

Milk HMO composition at 6 wk postpartum is associated with several anthropometry measures up to 6 mo of age in a potential secretor status-specific manner, with largely different HMOs associating with anthropometry from 12 mo to 4 y of age.

Novel Method for Adulterated Identification of Saneen Goat Milk Based on Free Oligosaccharides α3'-Galactosyllactose and N-Acetylhexaminyllactose as Marker Molecules

Methods for the detection of adulterated milk are essential for assessing the quality of goat milk products. We hypothesized that goat milk oligosaccharides could provide a basis for this purpose and compared the levels of α3'-galactosyllactose (α3'-GL) and N-acetylhexaminyllactose (NHL) between goat milk and bovine milk oligosaccharides using reverse-phase high-performance liquid chromatography. The α3'-GL was detected to be three times more abundant in goat milk than in bovine milk, whereas NHL showed the opposite trend. Linear relationships were established between the relative proportions of α3'-GL and NHL levels for different ratios of bovine and goat milk, with a minimum detection limit of 2% bovine milk. The new method was validated by analyses of adulterants in eight commercially available goat dairy products. Overall, the degree of adulteration in goat milk products can be determined based on the relative proportions of α3'-GL and NHL.

Human Milk Oligosaccharides Are Associated with Lactation Stage and Lewis Phenotype in a Chinese Population

Background: Human milk oligosaccharides (HMOs) are the third most abundant component of human milk. Various factors may affect the concentration of HMOs, such as the lactation period, Lewis blood type, and the maternal secretor gene status. Objectives: The purpose of this study is to investigate factors associated with HMO concentrations in Chinese populations. Methods: A sub-sample of 481 was randomly selected from a large cross-sectional study in China (n = 6481) conducted in eight provinces (Beijing, Heilongjiang, Shanghai, Yunnan, Gansu, Guangdong, Zhejiang, and Shandong) between 2011 and 2013. HMO concentrations were determined by a high-throughput UPLC-MRM method. Various factors were collected through face-to-face interviews. Anthropometric measurement was conducted by trained staff. Results: Median total HMO concentration was 13.6 g/L, 10.7 g/L, and 6.0 g/L for colostrum, transitional milk, and mature milk, respectively. HMO concentration decreased significantly as the lactation period increased (p < 0.0001). There were significant differences of average total HMO concentration between secretor mothers and non-secretor mothers (secretor 11.3 g/L vs. non-secretor 5.8 g/L, p < 0.0001). There were significant differences of average total HMO concentrations among three Lewis blood types (p = 0.003). Comparing with the concentration of total oligosaccharides of Le+ (a−b+), average of total oligosaccharides concentrations increased by 3.9 (Le+ (a+b−), p = 0.004) and 1.1 g/L (Le− (a−b−), p = 0.049). The volume of breast milk expressed and the province the mother came from affected the concentration of total oligosaccharides (all p < 0.0001). Maternal BMI (p = 0.151), age (p = 0.630), prematurity (p = 0.850), mode of delivery (p = 0.486), infants’ gender (p = 0.685), maternal education level (p = 0.989), maternal occupation (p = 0.568), maternal allergic history (p = 0.370), maternal anemia (p = 0.625), pregnancy-induced hypertension (p = 0.739), gestational diabetes (p = 0.514), and parity (p = 0.098) were not significantly correlated with the concentration of milk oligosaccharides. The concentrations of 2′-fucosyllactose (2′-FL), lacto-N-neotetraose (LNnT), sialyllacto-N-tetraose c (LSTc), lacto-N-fucopentaose I (LNFP-I), disialylated lacto-N-tetraose (DSLNT), difucosyl-para-lacto-N-neohexaose (DFpLNnH), difucosyl-lacto-N-hexaose (DFLNH[a]), and 3-sialyllactose (3′-SL) showed a gradual downward trend, while the concentration of 3-fucosyllactose (3-FL) showed a gradual upward trend among three lactation stages (p < 0.05). Conclusions: The concentration of HMOs changes throughout lactation, and it varies between different HMOs. HMO concentrations differed between lactation stage, maternal secretor gene status, Lewis blood type, volume of breast milk expressed, and the province the mother came from. Prematurity, mode of delivery, parity, infants’ gender, and maternal characteristics did not affect the HMO concentration. Geographical region may be not associated with HMOs concentration in human milk. There may be a mechanism for co-regulation of the secretion of some of the oligosaccharides such as 2′FL vs. 3FL, 2′FL vs. LNnT, and lacto-N-tetraose (LNT).

Chemical characterization and antineoplastic effect of oligosaccharides from Cabernet Franc red wine in mammary tumor model in mice

The present study characterized oligosaccharide compounds (Oligo) in Cabernet Franc red wine and investigated its antineoplastic effects against mammary tumor cells in vivo and in vitro, isolated or in combination with chemotherapy. The Oligo fraction was characterized by nuclear magnetic resonance spectroscopy and mass spectrometry. The complex mixture of Oligo showed high amounts of oligoxyloglucuronans, oligorhamnogalacturonans, oligoarabinogalactans, and oligoglucans, such as trehalose and isomaltotriose. To investigate the antineoplastic effects of Oligo, Female Swiss mice were subcutaneously inoculated with Ehrlich tumor cells and then received vehicle (distilled water, p.o.), Oligo solution (9, 35, or 70 mg/kg, p.o.), or methotrexate (1.5 mg/kg, i.p.). The treatments were administered in a conventional (21-d) or chemopreventive (42-d) protocol. Oligo reduced the growth of Ehrlich tumors in both protocols and increased the effectiveness of methotrexate in controlling tumor growth. Oligo did not reduce the viability of MCF-7, MDA-MB-231, MDA-MB-436, and HB4a human breast cells that were cultured for 48 h, showing no cytotoxicity. Overall, Oligo exerted an in vivo antineoplastic effect and modulated immune blood cells, dependent on treatment time, and was not directly cytotoxic to tumor cells. Thus, Oligo may indirectly regulate tumor cell development and may be a promising drug for cancer therapy in combination with methotrexate.

Effects of a milk oligosaccharide biosimilar on fecal characteristics, microbiota, and bile acid, calprotectin, and immunoglobulin concentrations of healthy adult dogs treated with metronidazole

In recent dog and cat experiments, a novel milk oligosaccharide biosimilar (GNU100) positively modulated fecal microbiota and metabolite profiles, suggesting benefits to gastrointestinal health. The objective of this study was to investigate the effects of GNU100 on the fecal characteristics, microbiota, and bile acid (BA) concentrations of healthy adult dogs treated with antibiotics. Twelve healthy adult female dogs (mean age: 3.74 ± 2.4 yr) were used in an 8-wk crossover design study (dogs underwent both treatments). All dogs were fed a control diet during a 2-wk baseline, then randomly allotted to 1 of 2 treatments (diet only or diet + 1% GNU100) for another 6 wk. From weeks 2 to 4, dogs were orally administered metronidazole (20 mg/kg BW) twice daily. Fecal scores were recorded daily and fresh fecal samples were collected at weeks 2, 4, 5, 6, and 8 for measurement of pH, dry matter, microbiota populations, and BA, immunoglobulin A, and calprotectin concentrations. On weeks 0, 4, and 8, blood samples were collected for serum chemistry and hematology analysis. All data were analyzed as repeated measures using the Mixed Models procedure of SAS version 9.4, with significance considered P < 0.05. Metronidazole increased (P < 0.0001) fecal scores (looser stools) and modified (P < 0.05) fecal microbiota and BA profiles. Using qPCR, metronidazole reduced fecal Blautia, Fusobacterium, Turicibacter, Clostridium hiranonis, and Faecalibacterium abundances, and increased fecal Streptococcus and Escherichia coli abundances. DNA sequencing analysis demonstrated that metronidazole reduced microbial alpha diversity and influenced the relative abundance of 20 bacterial genera and families. Metronidazole also increased primary BA and reduced secondary BA concentrations. Most antibiotic-induced changes returned to baseline by week 8. Fecal scores were more stable (P = 0.01) in GNU100-fed dogs than controls after antibiotic administration. GNU100 also influenced fecal microbiota and BA profiles, reducing (P < 0.05) the influence of metronidazole on microbial alpha diversity and returning some fecal microbiota and secondary BA to baseline levels at a quicker (P < 0.05) rate than controls. In conclusion, our results suggest that GNU100 supplementation provides benefits to dogs treated with antibiotics, providing more stable fecal scores, maintaining microbial diversity, and allowing for quicker recovery of microbiota and secondary BA profiles which play an essential role in gut health.

Human Milk Oligosaccharide Utilization in Intestinal Bifidobacteria Is Governed by Global Transcriptional Regulator NagR

Bifidobacterium longum subsp. infantis is a prevalent beneficial bacterium that colonizes the human neonatal gut and is uniquely adapted to efficiently use human milk oligosaccharides (HMOs) as a carbon and energy source. Multiple studies have focused on characterizing the elements of HMO utilization machinery in B. longum subsp. infantis; however, the regulatory mechanisms governing the expression of these catabolic pathways remain poorly understood. A bioinformatic regulon reconstruction approach used in this study implicated NagR, a transcription factor from the ROK family, as a negative global regulator of gene clusters encoding lacto-N-biose/galacto-N-biose (LNB/GNB), lacto-N-tetraose (LNT), and lacto-N-neotetraose (LNnT) utilization pathways in B. longum subsp. infantis. This conjecture was corroborated by transcriptome profiling upon nagR genetic inactivation and experimental assessment of binding of recombinant NagR to predicted DNA operators. The latter approach also implicated N-acetylglucosamine (GlcNAc), a universal intermediate of LNT and LNnT catabolism, and its phosphorylated derivatives as plausible NagR transcriptional effectors. Reconstruction of NagR regulons in various Bifidobacterium lineages revealed multiple potential regulon expansion events, suggesting evolution from a local regulator of GlcNAc catabolism in ancestral bifidobacteria to a global regulator controlling the utilization of mixtures of GlcNAc-containing host glycans in B. longum subsp. infantis and Bifidobacterium bifidum. IMPORTANCE The predominance of bifidobacteria in the gut of breastfed infants is attributed to the ability of these bacteria to metabolize human milk oligosaccharides (HMOs). Thus, individual HMOs such as lacto-N-tetraose (LNT) and lacto-N-neotetraose (LNnT) are considered promising prebiotics that would stimulate the growth of bifidobacteria and confer multiple health benefits to preterm and malnourished children suffering from impaired (stunted) gut microbiota development. However, the rational selection of HMO-based prebiotics is hampered by the incomplete knowledge of regulatory mechanisms governing HMO utilization in target bifidobacteria. This study describes NagR-mediated transcriptional regulation of LNT and LNnT utilization in Bifidobacterium longum subsp. infantis. The elucidated regulatory network appears optimally adapted to simultaneous utilization of multiple HMOs, providing a rationale to add HMO mixtures (rather than individual components) to infant formulas. The study also provides insights into the evolutionary trajectories of complex regulatory networks controlling carbohydrate metabolism in bifidobacteria.

Food Insecurity and Maternal Diet Influence Human Milk Composition between the Infant's Birth and 6 Months after Birth in Central-Africa

Although the World Health Organization (WHO) and UNICEF recommend that infants should be exclusively breastfed for the first 6 months of life, evidence is scarce on how the mother’s undernourishment status at delivery and maternal dietary factors influence human milk (HM) composition during the first 6 months of life in regions with high food insecurity. The maternal undernourishment status at delivery, maternal diet, and HM nutrients were assessed among 46 women and their 48 vaginally born infants in Bangui at 1, 4, 11, 18, and 25 weeks after birth through 24-h recalls and food consumption questionnaires from December 2017 to June 2019 in the context of the "Mother-to-Infant TransmIssion of microbiota in Central-Africa" (MITICA) study. High food insecurity indexes during the follow-up were significantly associated with them having lower levels of many of the human milk oligosaccharides (HMOs) that were measured and with lower levels of retinol (aß-coef = −0.2, p value = 0.04), fatty acids (aß-coef = −7.2, p value = 0.03), and amino acids (aß-coef = −2121.0, p value < 0.001). On the contrary, women from food-insecure households displayed significantly higher levels of lactose in their HM (aß-coef = 3.3, p value = 0.02). In parallel, the consumption of meat, poultry, and fish was associated with higher HM levels of many of the HMOs that were measured, total amino acids (aß-coef = 5484.4, p value < 0.001), and with lower HM levels of lactose (aß-coef = −15.6, p value = 0.01). Food insecurity and maternal diet had a meaningful effect on HM composition with a possible impact being an infant undernourishment risk. Our results plead for consistent actions on food security as an effective manner to influence the nutritional content of HM and thereby, potentially improve infant survival and healthy growth.

Associations of Human Milk Oligosaccharides with Infant Brain Tissue Organization and Regional Blood Flow at 1 Month of Age

Animal studies have shown that human milk oligosaccharides (HMOs) are important in early brain development, yet their roles have not been assessed in humans. The purpose of this study was to determine the associations of HMOs with MRI indices of tissue microstructure and regional cerebral blood flow (rCBF) in infants. Mother–infant pairs (N = 20) were recruited at 1 month postpartum. Milk was assayed for the concentrations of the HMOs 2′-fucosyllactose (2′FL), 3-fucosyllactose (3FL), 3′-sialyllactose (3′SL), and 6′-sialyllactose (6′SL). Diffusion and arterial spin labeling measures were acquired using a 3.0-Tesla MRI scanner. Multiple linear regression was used to assess the voxel-wise associations of HMOs with fractional anisotropy (FA), mean diffusivity (MD), and rCBF values across the brain. After adjusting for pre-pregnancy BMI, sex, birthweight, and postmenstrual age at time of scan, a higher 2′FL concentration was associated with reduced FA, increased MD, and reduced rCBF in similar locations within the cortical mantle. Higher 3FL and 3′SL concentrations were associated with increased FA, reduced MD, and increased rCBF in similar regions within the developing white matter. The concentration of 6′SL was not associated with MRI indices. Our data reveal that fucosylated and sialylated HMOs differentially associate with indices of tissue microstructure and rCBF, suggesting specific roles for 2′FL, 3FL, and 3′SL in early brain maturation.

Infant Gut Microbial Metagenome Mining of α-l-Fucosidases with Activity on Fucosylated Human Milk Oligosaccharides and Glycoconjugates

The gastrointestinal microbiota members produce α-l-fucosidases that play key roles in mucosal, human milk, and dietary oligosaccharide assimilation. Here, 36 open reading frames (ORFs) coding for putative α-l-fucosidases belonging to glycosyl hydrolase family 29 (GH29) were identified through metagenome analysis of breast-fed infant fecal microbiome. Twenty-two of those ORFs showed a complete coding sequence with deduced amino acid sequences displaying the highest degree of identity with α-l-fucosidases from Bacteroides thetaiotaomicron, Bacteroides caccae, Phocaeicola vulgatus, Phocaeicola dorei, Ruminococcus gnavus, and Streptococcus parasanguinis. Based on sequence homology, 10 α-l-fucosidase genes were selected for substrate specificity characterization. The α-l-fucosidases Fuc18, Fuc19A, Fuc35B, Fuc39, and Fuc1584 showed hydrolytic activity on α1,3/4-linked fucose present in Lewis blood antigens and the human milk oligosaccharide (HMO) 3-fucosyllactose. In addition, Fuc1584 also hydrolyzed fucosyl-α-1,6-N-acetylglucosamine (6FN), a component of the core fucosylation of N-glycans. Fuc35A and Fuc193 showed activity on α1,2/3/4/6 linkages from H type-2, Lewis blood antigens, HMOs and 6FN. Fuc30 displayed activity only on α1,6-linked l-fucose, and Fuc5372 showed a preference for α1,2 linkages. Fuc2358 exhibited a broad substrate specificity releasing l-fucose from all the tested free histo-blood group antigens, HMOs, and 6FN. This latest enzyme also displayed activity in glycoconjugates carrying lacto-N-fucopentaose II (Lea) and lacto-N-fucopentaose III (Lex) and in the glycoprotein mucin. Fuc18, Fuc19A, and Fuc39 also removed l-fucose from neoglycoproteins and human α-1 acid glycoprotein. These results give insight into the great diversity of α-l-fucosidases from the infant gut microbiota, thus supporting the hypothesis that fucosylated glycans are crucial for shaping the newborn microbiota composition. IMPORTANCE α-l-Fucosyl residues are frequently present in many relevant glycans, such as human milk oligosaccharides (HMOs), histo-blood group antigens (HBGAs), and epitopes on cell surface glycoconjugate receptors. These fucosylated glycans are involved in a number of mammalian physiological processes, including adhesion of pathogens and immune responses. The modulation of l-fucose content in such processes may provide new insights and knowledge regarding molecular interactions and may help to devise new therapeutic strategies. Microbial α-l-fucosidases are exoglycosidases that remove α-l-fucosyl residues from free oligosaccharides and glycoconjugates and can be also used in transglycosylation reactions to synthesize oligosaccharides. In this work, α-l-fucosidases from the GH29 family were identified and characterized from the metagenome of fecal samples of breastfed infants. These enzymes showed different substrate specificities toward HMOs, HBGAs, naturally occurring glycoproteins, and neoglycoproteins. These novel glycosidase enzymes from the breast-fed infant gut microbiota, which resulted in a good source of α-l-fucosidases, have great biotechnological potential.

1H NMR Metabolomics of Chinese Human Milk at Different Stages of Lactation among Secretors and Non-Secretors

Human milk is an intricate, bioactive food promoting infant health. We studied the composition of human milk samples collected over an 8-month lactation using ¹H NMR metabolomics. A total of 72 human breast milk samples were collected from ten Chinese mothers at eight different time points. The concentrations of ten human milk oligosaccharides (HMOs), fucose and lactose were quantified. Six of the mothers were classified as Lewis-positive secretors (Se⁺Le⁺) and four as Lewis-positive non-secretors (Se⁻Le⁺) based on the levels of 2′-fucosyllactose (2′-FL), lacto-N-fucopentaose (LNFP) II, lactodifucotetraose (LDFT) and lacto-N-neotetraose (LNnT). Acetate, citrate, short/medium-chain fatty acids, glutamine and urea showed a time-dependent trend in relation to the stage of lactation. The concentrations of 2′-FL, 3-FL (3-fucosyllactose), 3′-SL (3′-sialyllactose), LDFT, LNFP I, LNFP II, LNFP III, LNnT, LNT (lacto-N-tetraose), and fucose were statistically different between secretors and non-secretors. A temporal difference of approximately 1–2 months between the development of non-secretor and secretor HMO profiles was shown. The results highlighted the importance of long-term breastfeeding, especially among non-secretors.

Human Milk Oligosaccharides Are Present in Amniotic Fluid and Show Specific Patterns Dependent on Gestational Age

(1) Background: Human milk oligosaccharides (HMOs) are already found in maternal circulation in early pregnancy, changing with gestational age. HMOs are also present in cord blood and amniotic fluid (AF). We aimed to assess HMO profiles in AF over the course of gestation. (2) Methods: AF was collected during diagnostic amniocentesis, fetal surgery, or C-section from 77 women with a gestational age of ranging from 14.3 to 40.9 weeks. Samples were analysed using high performance liquid chromatography with fluorescence detection. (3) Results: We found lactose and up to 16 HMO structures in all AF samples investigated, starting at 14 weeks of gestation. Overall, 3′-sialyllactose (3′SL) and 2′-fucosyllactose (2′FL) were the most abundant HMOs. Individual and total HMO concentrations were significantly positively correlated with gestational age. HMO composition also changed between early, mid- and late pregnancy, with relative concentrations of 3′SL significantly decreasing (44%, 25%, 24%) and 2′FL increasing (7%, 13%, 21%), respectively. (4) Conclusion: Our study shows that HMOs are already present in AF early in pregnancy. This demonstrates extensive contact of the fetus with a broad variety of HMOs, suggesting roles for HMOs in fetal tissue development during the time course of pregnancy.

Human Milk Bioactives: Future Perspective

Human milk is a dynamic, complex fluid that offers much more than nutrition to infants. The macronutrient content of human milk has been well characterized and described. However, human milk is not a simple matrix of protein, carbohydrate, fat, and micronutrients. The National Institutes of Health have defined bioactives in food as elements that "affect biological processes or substrates and hence have an impact on body function or condition and ultimately health." Bioactives are cells, anti-infectious and anti-inflammatory agents, growth factors, and prebiotics that are naturally present in human milk. They may explain the differences in health outcomes observed between breastfed and non-breastfed infants. They influence the development of the immune and gastrointestinal systems, gut microbiota, neurodevelopment, metabolic health, and protection against infection. Human milk oligosaccharides are one bioactive that have been an increasingly popular area of research. This review provides a broad overview of some bioactive components that positively affect the immune system and touches on certain well-known growth factors present in human milk. Future research will look at the interplay of the multitude of bioactive components in human milk as a biological system and beyond singular compounds.

Selected Human Milk Oligosaccharides Added to Infant Formulas for Term Infants

The benefits of breastfeeding, such as reduced risk of gastrointestinal and respiratory tract infections, depend largely on the presence of bioactive compounds in breast milk, including human milk oligosaccharides (HMOs). The presence of HMOs represents one of the largest differences in composition between breast milk and infant formula. Currently, progress in biotechnology allows the production of selected HMOs such as 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT), which are increasingly being added to infant formulas to narrow the difference between breast milk and formula. It is important to differentiate HMOs naturally occurring in human breast milk from those biotechnologically produced, which, while identical to HMOs in breast milk, do not originate from breast milk. This chapter summarizes basic facts about HMOs, findings from observational studies assessing the relationship between specific HMOs and clinical effects, and evidence from randomized controlled trials with structures identical to HMOs in breast milk added to infant formulas. Overall, the findings from some recently published trials provide reassurance that infant formulas supplemented with selected structures identical to HMOs, specifically 2'-FL with/out LNnT, are safe and well tolerated, and may have favorable effects on some health outcomes and medication usage. Further studies are needed.

Quality evaluation of Codonopsis Radix and processed products based on the analysis of monosaccharides and oligosaccharides by liquid chromatography coupled with charged aerosol detector

INTRODUCTION

Codonopsis Radix (CR) is an edible food and traditional Chinese herb medicine that is widely used in China and Southeast Asia. Saccharides, including fructo-oligosaccharides (FOS) and polysaccharides, are among the most important active substances in CR. However, a quality evaluation of CR based on oligosaccharides has not been conducted.

OBJECTIVE

This study aimed to establish a high-performance liquid chromatography coupled with charged aerosol detector method (HPLC-CAD) for the quality evaluation of CR and processed products based on analysis of monosaccharides and oligosaccharides.

METHOD

A sensitive and rapid HPLC-CAD method for the simultaneous determination of two monosaccharides (D-fructose and D-glucose), sucrose, and FOS (GF2-GF6) was established to evaluate the quality of CR for the first time. In the present study, 65 batches of CR from three species of the genus Codonopsis were analysed using multivariate statistical techniques. Furthermore, the effects of cultivation management measures (plant growth retardants supply, harvesting time, and growth period) and primary process (drying methods) in the production areas on the target compounds were studied by analysing 34 batches of processed samples.

RESULTS

Different varieties of CR resulted in considerably different saccharide contents. Cultivation management measures and processing method remarkably affected the quality of CR. Low concentration of plant growth retardants was recommended. The best harvest time is in October after 4 years of growth. Dryer-drying was suggested to meet the requirement for large-scale processing.

CONCLUSION

This method would provide an efficient analytical tool for monosaccharides and oligosaccharides of CR and contribute to the improvement of CR quality.

Chemical Fingerprint Analysis and Quantitative Analysis of Saccharides in Morindae Officinalis Radix by HPLC-ELSD

A method based on high performance liquid chromatography with evaporative light scattering detection (HPLC-ELSD) was developed for the quantitative analysis of three active compounds and chemical fingerprint analyses of saccharides in Morindae officinalis radix. Ten batches of Morindae officinalis radix were collected from different plantations in the Guangdong region of China and used to establish the fingerprint. The samples were separated with a COSMOIL Sugar-D column (4.6 mm × 250 mm, 5 μm) by using gradient elution with water (A) and acetonitrile (B). In addition, Trapped-Ion-Mobility (tims) Time-Of-Flight (tims TOF) was used to identify saccharides of Morindae officinalis radix. Fingerprint chromatogram presented 26 common characteristic peaks in the roots of Morinda officinalis How, and the similarities were more than 0.926. In quantitative analysis, the three compounds showed good regression (r = 0.9995-0.9998) within the test ranges, and the recoveries of the method were in the range of 96.7-101.7%. The contents of sucrose, kestose and nystose in all samples were determined as 1.21-7.92%, 1.02-3.37%, and 2.38-6.55%, respectively. The developed HPLC fingerprint method is reliable and was validated for the quality control and identification of Morindae officinalis radix and can be successfully used to assess the quality of Morindae officinalis radix.

Prebiotic potential and chemical characterization of the poly and oligosaccharides present in the mucilage of Opuntia ficus-indica and Opuntia joconostle

The mucilage extracted from the convection-dried cladodes of O. ficus-indica and O. joconostle, two species of economic importance, delivered three fractions after methanol precipitation. Two were composed of high molar mass polysaccharides, and one included water-soluble mono-, di-, and oligosaccharides. The large polysaccharides have a molar mass range of 4.0 × 10³ to 8.0 × 10⁵ g·mol^-1 and are consistently composed of galactose, arabinose, xylose, and rhamnose; however, the content of galacturonic acid was different between both fractions and species. Their fermentability by selected probiotics was relatively low, 11-27 % compared to glucose, and decreased with increasing levels of galacturonic acid in the molecules. In the third fraction, previously unreported oligosaccharides were found. These include simple- and complex-structured galactooligosaccharides with arabinosyl-, xylosyl- and galacturonosyl acid residues. Their fermentability by prebiotic species can be ascribed more to their structural characteristics and monosaccharide composition than their molecular dimensions.

Reverse tracing anti-thrombotic active ingredients from dried Rehmannia Radix based on multidimensional spectrum-effect relationship analysis of steaming and drying for nine cycles

ETHNOPHARMACOLOGICAL RELEVANCE

In traditional Chinese medicine (TCM) and modern pharmacodynamics, dried Rehmannia Radix (DRR) possesses prominent anti-thrombotic activity that decreases after processing by nine steaming and drying cycles to develop processed Rehmannia Radix (PRR). Due to the complexity of the DRR components, the chemical mechanism leading to efficacy changes of DRR caused by processing is still unclear.

AIM OF STUDY

This study aimed to trace the anti-thrombotic active compounds of DRR and different degrees of processed RR (PRR) and to evaluate the synergistic effects among different active components.

MATERIALS AND METHODS

The anti-thrombotic active chemical fraction of DRR extracts was evaluated. Targeted fractions of the processed products of RR were prepared at different processing stages. The changes in monosaccharides, oligosaccharides and secondary metabolites during processing were characterized by multidimensional high-performance liquid chromatography (HPLC). The anti-thrombotic effects of targeted fractions of different RR samples were evaluated by analyzing the length of tail thrombus (LT) and serum biochemical indicators in carrageenan-induced tail-thrombus mice. The spectrum-effect relationships were investigated by partial least squares regression (PLSR) analysis and gray correlation analysis (GRA). Finally, the active compounds were screened by spectrum-effect relationship analysis and validated in vivo, and their synergistic effects were determined by Webb's fraction multiplication method.

RESULTS

Six ingredients highly associated with anti-thrombotic activities were screened out by the spectrum-effect relationship analysis, of which oligosaccharides (stachyose, sucrose and raffinose) and iridoid glycosides (catalpol, leonuride and melitoside) possessed a synergistic effect on tumor necrosis factors (TNF-α), interleukin 1β (IL-1β) and plasminogen activator inhibitor 1 (PAI-1)/tissue-type plasminogen activator (t-PA) ratio in vivo with synergistic coefficient (SC) > 1.

CONCLUSION

The main material basis of the anti-thrombotic activities of DRR is oligosaccharide components of stachyose, raffinose and sucrose, iridoid glycosides components of catalpol, leonuride and melittoside. The two kinds of components exert synergistic anti-thrombotic effects by inhibiting the expression of inflammatory factors and regulating the balance of the fibrinolysis system.

Potential Benefits of Bovine Colostrum in Pediatric Nutrition and Health

Bovine colostrum (BC), the first milk produced from cows after parturition, is increasingly used as a nutritional supplement to promote gut function and health in other species, including humans. The high levels of whey and casein proteins, immunoglobulins (Igs), and other milk bioactives in BC are adapted to meet the needs of newborn calves. However, BC supplementation may improve health outcomes across other species, especially when immune and gut functions are immature in early life. We provide a review of BC composition and its effects in infants and children in health and selected diseases (diarrhea, infection, growth-failure, preterm birth, necrotizing enterocolitis (NEC), short-bowel syndrome, and mucositis). Human trials and animal studies (mainly in piglets) are reviewed to assess the scientific evidence of whether BC is a safe and effective antimicrobial and immunomodulatory nutritional supplement that reduces clinical complications related to preterm birth, infections, and gut disorders. Studies in infants and animals suggest that BC should be supplemented at an optimal age, time, and level to be both safe and effective. Exclusive BC feeding is not recommended for infants because of nutritional imbalances relative to human milk. On the other hand, adverse effects, including allergies and intolerance, appear unlikely when BC is provided as a supplement within normal nutrition guidelines for infants and children. Larger clinical trials in infant populations are needed to provide more evidence of health benefits when patients are supplemented with BC in addition to human milk or formula. Igs and other bioactive factors in BC may work in synergy, making it critical to preserve bioactivity with gentle processing and pasteurization methods. BC has the potential to become a safe and effective nutritional supplement for several pediatric subpopulations.

Sequence-based genome-wide association study of individual milk mid-infrared wavenumbers in mixed-breed dairy cattle

BACKGROUND

Fourier-transform mid-infrared (FT-MIR) spectroscopy provides a high-throughput and inexpensive method for predicting milk composition and other novel traits from milk samples. While there have been many genome-wide association studies (GWAS) conducted on FT-MIR predicted traits, there have been few GWAS for individual FT-MIR wavenumbers. Using imputed whole-genome sequence for 38,085 mixed-breed New Zealand dairy cattle, we conducted GWAS on 895 individual FT-MIR wavenumber phenotypes, and assessed the value of these direct phenotypes for identifying candidate causal genes and variants, and improving our understanding of the physico-chemical properties of milk.

RESULTS

Separate GWAS conducted for each of 895 individual FT-MIR wavenumber phenotypes, identified 450 1-Mbp genomic regions with significant FT-MIR wavenumber QTL, compared to 246 1-Mbp genomic regions with QTL identified for FT-MIR predicted milk composition traits. Use of mammary RNA-seq data and gene annotation information identified 38 co-localized and co-segregating expression QTL (eQTL), and 31 protein-sequence mutations for FT-MIR wavenumber phenotypes, the latter including a null mutation in the ABO gene that has a potential role in changing milk oligosaccharide profiles. For the candidate causative genes implicated in these analyses, we examined the strength of association between relevant loci and each wavenumber across the mid-infrared spectrum. This revealed shared association patterns for groups of genomically-distant loci, highlighting clusters of loci linked through their biological roles in lactation and their presumed impacts on the chemical composition of milk.

CONCLUSIONS

This study demonstrates the utility of FT-MIR wavenumber phenotypes for improving our understanding of milk composition, presenting a larger number of QTL and putative causative genes and variants than found from FT-MIR predicted composition traits. Examining patterns of significance across the mid-infrared spectrum for loci of interest further highlighted commonalities of association, which likely reflects the physico-chemical properties of milk constituents.

Changes in HMO Concentrations throughout Lactation: Influencing Factors, Health Effects and Opportunities

Human milk oligosaccharides (HMOs) are important functional biomolecules in human breast milk. Understanding the factors influencing differences in HMO composition and changes in their concentration over lactation can help to design feeding strategies that are well-adapted to infant's needs. This review summarises the total and individual concentration of HMOs from data published from 1999 to 2019. Studies show that the HMO concentrations are highest in colostrum (average 9-22 g/L), followed by slightly lower concentrations in transitional milk (average 8-19 g/L), with a gradual decline in mature milk as lactation progresses, from 6-15 g/L in breast milk collected within one month of birth, to 4-6 g/L after 6 months. Significant differences in HMO composition have been described between countries. Different HMOs were shown to be predominant over the course of lactation, e.g., 3-fucosyllactose increased over lactation, whereas 2'-fucosyllactose decreased. Recent clinical studies on infant formula supplemented with 2'-fucosyllactose in combination with other oligosaccharides showed its limited beneficial effect on infant health.

Human Milk Oligosaccharide Profiles over 12 Months of Lactation: The Ulm SPATZ Health Study

Human milk oligosaccharides (HMOs) have specific dose-dependent effects on child health outcomes. The HMO profile differs across mothers and is largely dependent on gene expression of specific transferase enzymes in the lactocytes. This study investigated the trajectories of absolute HMO concentrations at three time points during lactation, using a more accurate, robust, and extensively validated method for HMO quantification. We analyzed human milk sampled at 6 weeks (n = 682), 6 months (n = 448), and 12 months (n = 73) of lactation in a birth cohort study conducted in south Germany, using label-free targeted liquid chromatography mass spectrometry (LC-MS²). We assessed trajectories of HMO concentrations over time and used linear mixed models to explore the effect of secretor status and milk group on these trajectories. Generalized linear model-based analysis was used to examine associations between HMOs measured at 6 weeks of lactation and maternal characteristics. Results: Overall, 74%, 18%, 7%, and 1% of human milk samples were attributed to milk groups I, II, III, and IV, respectively. Most HMO concentrations declined over lactation, but some increased. Cross-sectionally, HMOs presented high variations within milk groups and secretor groups. The trajectories of HMO concentrations during lactation were largely attributed to the milk group and secretor status. None of the other maternal characteristics were associated with the HMO concentrations. The observed changes in the HMO concentrations at different time points during lactation and variations of HMOs between milk groups warrant further investigation of their potential impact on child health outcomes. These results will aid in the evaluation and determination of adequate nutrient intakes, as well as further (or future) investigation of the dose-dependent impact of these biological components on infant and child health outcomes.

A general strategy for the structural determination of carbohydrates by multi-dimensional NMR spectroscopies

Two-dimensional NMR spectroscopies are one of the most frequently used techniques for the structural determination of carbohydrates. However, the data analysis is challenging because of the signal overlap in the ¹H homonuclear correlation spectra. We attempted to explore a general strategy for the structural determination of carbohydrates by combined multi-dimensional spectroscopies. The strategy was applied to a human milk oligosaccharide lacto-N-difucohexaose I, that has been previously studied by conventional two-dimensional NMR spectroscopy. Assignment of the intra-residue resonances of the hexasaccharide using the three-dimensional spectrum was straightforward. Consequently, data analysis of the multi-dimensional spectra was significantly simplified, leading to a quicker determination of the intra- and inter-residue connections in the hexasaccharide. Application of the NMR strategy to chondroitin sulfate from bovine cartilage revealed two repeating disaccharide regions of the A and C units of chondroitin sulfate, indicating the high potential of this technique for the structural determination of complex polysaccharides.

Longitudinal Changes in Human Milk Oligosaccharides (HMOs) Over the Course of 24 Months of Lactation

BACKGROUND

Human milk oligosaccharides (HMOs) are complex glycans that are highly abundant in human milk. While over 150 HMOs have been identified, it is unknown how individual HMOs change in concentration over 24 months of lactation.

OBJECTIVES

To understand how HMO concentrations change over 24 months of lactation.

METHODS

Breast milk samples were collected from participants in a longitudinal cohort study of Hispanic mother-infant pairs at 1, 6, 12, 18, and 24 months postpartum. Concentrations of 19 of the most abundant HMOs were measured using HPLC. Because the parent study is ongoing and not all participants have finished all time points yet, the sample sizes ranged per time point (n = 207 at 1 month; n = 109 at 6 months; n = 83 at 12 months; n = 59 at 18 months; and n = 28 at 24 months). Approximately 88% of participants were classified as HMO secretors-a genetic factor that affects concentrations of HMOs such as 2'fucosyllactose (2'FL) and lacto-N-fucopentaose I-while the remaining 12% were classified as nonsecretors. Mixed models were used to examine changes in HMO concentrations and relative abundances over the course of lactation.

RESULTS

The majority of HMOs significantly decreased in concentration over the course of lactation. The exceptions were 2'FL, sialyl-lacto-N-tetraose b, and disialyl-lacto-N-tetraose, which did not change with time, and 3-fucosyllactose (3FL) and 3'-sialyllactose (3'SL), which significantly increased. The concentration of 3FL increased 10-fold, from 195 (IQR 138-415) μg/mL at 1 month to 1930 (1100-2630) μg/mL at 24 months, while 3'SL increased 2-fold, from 277 (198-377) μg/mL to 568 (448-708) μg/mL over the same time period.

CONCLUSIONS

These results indicate that HMOs do not decrease in concentration uniformly across lactation. In particular, 3FL and 3'SL increased over the course of lactation in this cohort. Future studies are required to fully understand the functions of these HMOs.

Human Milk Oligosaccharide Concentrations and Infant Intakes Are Associated with Maternal Overweight and Obesity and Predict Infant Growth

Human milk oligosaccharides (HMOs) are bioactive molecules playing a critical role in infant health. We aimed to quantify the composition of HMOs of women with normal weight (18.5–24.9 kg/m²), overweight (25.0–29.9 kg/m²), or obesity (30.0–60.0 kg/m²) and determine the effect of HMO intake on infant growth. Human milk (HM) samples collected at 2 months (2 M; n = 194) postpartum were analyzed for HMO concentrations via high-performance liquid chromatography. Infant HM intake, anthropometrics and body composition were assessed at 2 M and 6 M postpartum. Linear regressions and linear mixed-effects models were conducted examining the relationships between maternal BMI and HMO composition and HMO intake and infant growth over the first 6 M, respectively. Maternal obesity was associated with lower concentrations of several fucosylated and sialylated HMOs and infants born to women with obesity had lower intakes of these HMOs. Maternal BMI was positively associated with lacto-N-neotetraose, 3-fucosyllactose, 3-sialyllactose and 6-sialyllactose and negatively associated with disialyllacto-N-tetraose, disialyllacto-N-hexaose, fucodisialyllacto-N-hexaose and total acidic HMOs concentrations at 2 M. Infant intakes of 3-fucosyllactose, 3-sialyllactose, 6-sialyllactose, disialyllacto-N-tetraose, disialyllacto-N-hexaose, and total acidic HMOs were positively associated with infant growth over the first 6 M of life. Maternal obesity is associated with changes in HMO concentrations that are associated with infant adiposity.

ι-Carrageenan Tetrasaccharide from ι-Carrageenan Inhibits Islet β Cell Apoptosis Via the Upregulation of GLP-1 to Inhibit the Mitochondrial Apoptosis Pathway

ι-Carrageenan performs diversified biological activities but has low bioavailability. ι-Carrageenan tetrasaccharide (ιCTs), a novel marine oligosaccharide prepared by the marine enzyme Cgi82A, was investigated for its effects on insulin resistance in high-fat and high-sucrose diet mice. Oral administration of ιCTs (ιCTs-L 30.0 mg/kg·bw, ιCTs-H 90.0 mg/kg·bw) decreased fasting blood glucose by 35.1% ± 1.41 (P < 0.01) and 27.4% ± 0.420 (P < 0.05), and enhanced glucose tolerance. Besides, ιCTs-L ameliorated islet vacuolization, decreased the β cell apoptosis by 21.8% ± 0.200 (P < 0.05), and promoted insulin secretion by 5.41% ± 0.0173 (P < 0.01) through pancreatic hematoxylin and eosin (H&E) staining, TUNEL staining, and insulin-glucagon immunostaining analysis. Interestingly, ιCTs-L and ιCTs-H treatment increased the incretin GLP-1 content in serum by 22.1% ± 0.402 (P < 0.01) and 10.7% ± 0.0935 (P < 0.05) respectively, through regulating the bile acid levels, which contributed to the inhibition of β cell apoptosis. Mechanically, ιCTs upregulated the expression of the GLP-1 receptor (GLP-1R) and protein kinase A (PKA) in the GLP-1/cAMP/PKA signaling pathway, and further inhibited the expression of cytochrome C and caspase 3 in the mitochondrial apoptotic pathway. In conclusion, this study suggested that ιCTs alleviated insulin resistance by GLP-1-mediated inhibition of β cell apoptosis and proposed a new strategy for developing potential functional foods that prevent insulin resistance.

Chemical stabilization of dispersed Escherichia coli for enhanced recovery with a handheld electroflotation system and detection by Loop-mediated Isothermal AMPlification

Constraints related to sample preparation are some of the primary obstacles to widespread deployment of molecular diagnostics for rapid detection of trace quantities (≤103 CFU/mL) of food-borne pathogens. In this research, we report a sample preparation method using a novel handheld electroflotation system to concentrate and recover dilute quantities (102-103 CFU/mL) of Escherichia coli (E. coli) 25922 in artificially contaminated samples for reliable, rapid detection by loop-mediated isothermal amplification (LAMP). To protect suspended cells from shear stresses at bubble surfaces, a non-ionic surfactant (Pluronic-F68) and flocculant (chitosan oligosaccharide) were used to aggregate cells and reduce their surface hydrophobicity. Effective conditions for recovery were determined through multifactorial experiments including various concentrations of Pluronic-F68 (0.001, 0.01, 0.1, 1 g L-1), chitosan oligosaccharide (0.01, 0.1, 1, 10 g L-1), bacteria (102, 103, 104 CFU/mL E. coli 25922), recovery times (10, 15 and 20 minutes), and degrees of turbulent gas flux ("high" and "low"). The automated electroflotation system was capable of concentrating effectively all of the bacteria from a large sample (380 mL 0.1 M potassium phosphate buffer containing 102 CFU/mL E. coli) into a 1 mL recovered fraction in less than 30 minutes. This enabled detection of bacterial contaminants within 2 hours of collecting the sample, without a specialized laboratory facility or traditional enrichment methods, with at least a 2-3 order of magnitude improvement in detection limit compared to direct assay with LAMP.

High-resolution method for isocratic HPLC analysis of inulin-type fructooligosaccharides

In recent decades, strategies to improve human health by modulating the gut microbiota have developed rapidly. One of the most prominent is the use of prebiotics, which can lead to a higher abundance of health-promoting microorganisms in the gut. Currently, oligosaccharides dominate the prebiotic sector due to their ability to promote the growth and activity of probiotic bacteria selectively. Extensive efforts are made to develop effective production strategies for the synthesis of prebiotic oligosaccharides, including the use of microbial enzymes. Within the genus Lactobacillus, several inulosucrases have been identified, which are suitable for the synthesis of prebiotic inulin-type fructooligosaccharides (inulin-FOS). In this study, a truncated version of the inulosucrase from Lactobacillus gasseri DSM 20604 was used for the efficient synthesis of inulin-FOS. Product titers of 146.2 ± 7.4 g inulin-FOSL^-1 were achieved by the catalytic activity of the purified recombinant protein InuGB-V3. A time and resource-saving HPLC method for rapid analysis of inulin-FOS in isocratic mode was developed and optimized, allowing baseline separated analysis of inulin-FOS up to a degree of polymerization (DP) of five in less than six minutes. Long-chain inulin-FOS with a DP of 17 can be analyzed in under 45 min. The developed method offers the advantages of isocratic HPLC analysis, such as low flow rates, high sensitivity, and the use of a simple, inexpensive chromatographic setup. Furthermore, it provides high-resolution separation of long-chain inulin-FOS, which can usually only be achieved with gradient systems.

High-throughput glycomic analyses reveal unique oligosaccharide profiles of canine and feline milk samples

Oligosaccharides are important components of milk, serving as substrates for the intestinal microbiota, acting as antimicrobials that prevent pathogen colonization, and supporting the developing gastrointestinal immune system of neonates. Nutrient composition of canine and feline milk samples has been described previously, but little is known about the oligosaccharide content. Therefore, the objective of this study was to characterize canine and feline milk samples using a high-throughput glycomics approach. 23 dogs (9 Labrador retriever and 14 Labrador retriever x golden retriever crossbreed) and 6 domestic shorthair cats were recruited to the study. Milk samples were collected by manual expression at time points after parturition. Samples were collected across 2 phases per species, differentiated by maternal diet. Following extraction, oligosaccharide content was determined by liquid chromatography-mass spectrometry (LC-MS). In canine milk samples, 3 structures accounted for over 90% of all oligosaccharides detected across two diet groups. These were 3’-sialyllactose, 6’-sialyllactose, and 2’-fucosyllactose. In feline samples, a more diverse range of oligosaccharides was detected, with up to 16 structures present at relative abundance >1% of the total. Difucosyllactose-N-hexaose b, 3’-sialyllactose and lacto-N-neohexaose were all detected at abundances >10% in feline milk samples. Statistically significant differences (p<0.05) in oligosaccharide abundances were observed between collection time points and between diet groups within species. These data explore the oligosaccharide content of canine and feline maternal milk, representing an opportunity to generate a fundamental understanding of the nutritional needs of new-born puppies and kittens.

De Novo Structural Determination of the Oligosaccharide Structure of Hemocyanins from Molluscs

A number of studies have shown that glycosylation of proteins plays diverse functions in the lives of organisms, has crucial biological and physiological roles in pathogen–host interactions, and is involved in a large number of biological events in the immune system, and in virus and bacteria recognition. The large amount of scientific interest in glycoproteins of molluscan hemocyanins is due not only to their complex quaternary structures, but also to the great diversity of their oligosaccharide structures with a high carbohydrate content (2–9%). This great variety is due to their specific monosaccharide composition and different side chain composition. The determination of glycans and glycopeptides was performed with the most commonly used methods for the analysis of biomolecules, including peptides and proteins, including Matrix Assisted Laser Desorption/Ionisation–Time of Flight (MALDI-TOF-TOF), Liquid Chromatography - Electrospray Ionization-Mass Spectrometry (LC/ESI-MS), Liquid Chromatography (LC-Q-trap-MS/MS) or Nano- Electrospray Ionization-Mass Spectrometry (nano-ESI-MS) and others. The molluscan hemocyanins have complex carbohydrate structures with predominant N-linked glycans. Of interest are identified structures with methylated hexoses and xyloses arranged at different positions in the carbohydrate moieties of molluscan hemocyanins. Novel acidic glycan structures with specific glycosylation positions, e.g., hemocyanins that enable a deeper insight into the glycosylation process, were observed in Rapana venosa, Helix lucorum, and Haliotis tuberculata. Recent studies demonstrate that glycosylation plays a crucial physiological role in the immunostimulatory and therapeutic effect of glycoproteins. The remarkable diversity of hemocyanin glycan content is an important feature of their immune function and provides a new concept in the antibody–antigen interaction through clustered carbohydrate epitopes.

Do Human Milk Oligosaccharides Protect Against Infant Atopic Disorders and Food Allergy?

Atopic disorders (AD), often coexistent with food allergy (FA), start developing in early life and have lifelong health consequences. Breastfeeding is thought to be protective against AD and FA, but the data are controversial, and mechanisms are not well understood. Human milk oligosaccharides (HMOs) are complex carbohydrates that are abundant in human milk. These are thought to contribute to the development of the infant immune system by (i) promoting healthy microbiome, (ii) inhibiting pathogen binding to gut mucosa and (iii) modulating the immune system. Differences in microbiome composition between allergic and healthy infants have been observed, regardless of breastfeeding history. To date, limited studies have examined the preventive effects of HMOs on AD and FA in infants and current data relies on observation studies as trials of varying HMO intake through randomising individuals to breastfeeding are unethical. There is evidence for beneficial effects of breastfeeding on lowering the risks of FA, eczema and asthma but there are inconsistencies amongst studies in the duration of breastfeeding, diagnostic criteria for AD and the age at which the outcome was assessed. Furthermore, current analytical methods primarily used today only allow detection of 16-20 major HMOs while more than 100 types have been identified. More large-scale longitudinal studies are required to investigate the role of HMO composition and the impact of changes over the lactation period in preventing AD and FA later in life.

Fast and Sensitive Detection of Oligosaccharides Using Desalting Paper Spray Mass Spectrometry (DPS-MS)

Conventional mass spectrometry (MS)-based analytical methods for small carbohydrate fragments (oligosaccharides, degree of polymerization 2-12) are time-consuming due to the need for an offline sample pretreatment such as desalting. Herein, we report a new paper spray ionization method, named desalting paper spray (DPS), which employs a piece of triangular filter paper for both sample desalting and ionization. Unlike regular paper spray ionization (PSI) and nanoelectrospray ionization (nanoESI), DPS-MS allows fast and sensitive detection of oligosaccharides in biological samples having complex matrices (e.g., Tris, PBS, HEPES buffers, or urine). When an oligosaccharide sample is loaded onto the filter paper substrate (10 × 5 mm, height × base) made mostly of cellulose, oligosaccharides are adsorbed on the paper via hydrophilic interactions with cellulose. Salts and buffers can be washed away using an ACN/H₂O (90/10 v/v) solution, while oligosaccharides can be eluted from the paper using a solution of ACN/H₂O/formic acid (FA) (10/90/1 v/v/v) and directly spray-ionized from the tip of the paper. Various saccharides at trace levels (e.g., 50 fmol) in nonvolatile buffer can be quickly analyzed by DPS-MS (<5 min per sample). DPS-MS is also applicable for direct detection of oligosaccharides from glycosyltransferase (GT) reactions, a challenging task that typically requires a radioactive assay. Quantitative analysis of acceptor and product oligosaccharides shows increased product with increased GT enzymes used for the reaction, a result in line with the radioactivity assay. This work suggests that DPS-MS has potential for rapid oligosaccharide analysis from biological samples.