The human milk metabolome reveals diverse oligosaccharide profiles

Campylobacter Abundance in Breastfed Infants and Identification of a New Species in the Global Enterics Multicenter Study

Campylobacter jejuni is a leading cause of bacterial diarrhea worldwide and is associated with high rates of mortality and growth stunting in children inhabiting low- to middle-resource countries. To better understand the impact of breastfeeding on Campylobacter infection in infants in sub-Saharan Africa and South Asia, we examined fecal microbial compositions, bacterial isolates, and their carbohydrate metabolic pathways in Campylobacter-positive infants <1 year of age from the Global Enterics Multicenter Study. Exclusively breastfed infants with diarrhea exhibited high Campylobacter abundances, and this negatively correlated with bacterial carbohydrate metabolism. Although C. jejuni and Campylobacter coli are prevalent among these infants, the second most abundant Campylobacter species was a new species, which we named "Candidatus Campylobacter infans." Asymptomatic Campylobacter carriers also possess significantly different proportions of specific gut microbes compared to diarrheal cases. These findings provide insight into Campylobacter infections in infants in sub-Saharan Africa and South Asia and help inform strategies aimed at eliminating campylobacteriosis in these areas.IMPORTANCECampylobacter is the primary cause of bacterial diarrhea in the United States and can lead to the development of the postinfectious autoimmune neuropathy known as Guillain-Barré syndrome. Also, drug-resistant campylobacters are becoming a serious concern both locally and abroad. In low- and middle-income countries (LMICs), infection with Campylobacter is linked to high rates of morbidity, growth stunting, and mortality in children, and breastfeeding is important for infant nutrition, development, and protection against infectious diseases. In this study, we examined the relationship between breastfeeding and Campylobacter infection and demonstrate the increased selection for C. jejuni and C. coli strains unable to metabolize fucose. We also identify a new Campylobacter species coinfecting these infants with a high prevalence in five of the seven countries in sub-Saharan Africa and South Asia examined. These findings indicate that more detailed studies are needed in LMICs to understand the Campylobacter infection process in order to devise a strategy for eliminating this pathogenic microbe.

Perspective: Human Milk Oligosaccharides: Fuel for Childhood Obesity Prevention?

Obesity begins early but has lifelong consequences for health and well-being. Breastfeeding is thought to be preventive against obesity, but the extent and cause of this association are not well understood. Human milk oligosaccharides (HMOs) are abundant in human milk and not present in commercially available infant formula. These complex sugars are thought to contribute to the development of the infant gut microbiome and immune system. Recently, they have been investigated as a potential link between breastfeeding and lower obesity risk. So far, only a few human studies have examined HMO composition of human milk in association with the infant's concurrent anthropometry or subsequent growth in infancy, with conflicting results. However, HMOs have been shown to modulate the gut microbiome profile by selectively promoting the growth of specific bacteria, such as bifidobacteria. Moreover, there are differences in the gut microbiome of lean and obese humans, and there is some evidence that the early composition of the gut microbiome can predict later obesity. Although it seems that HMOs might have a role in infant growth and adiposity, there is not enough consistent evidence to understand their potential role in obesity prevention. More data, particularly from large or longitudinal studies, are needed to clarify the functions of HMOs and other breast-milk components in determining long-term health.

Analysis of NMR Metabolomics Data

In this chapter, we summarize data preprocessing and data analysis strategies used for analysis of NMR data for metabolomics studies. Metabolomics consists of the analysis of the low molecular weight compounds in cells, tissues, or biological fluids, and has been used to reveal biomarkers for early disease detection and diagnosis, to monitor interventions, and to provide information on pathway perturbations to inform mechanisms and identifying targets. Metabolic profiling (also termed metabotyping) involves the analysis of hundreds to thousands of molecules using mainly state-of-the-art mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy technologies. While NMR is less sensitive than mass spectrometry, NMR does provide a wealth of complex and information rich metabolite data. NMR data together with the use of conventional statistics, modeling methods, and bioinformatics tools reveals biomarker and mechanistic information. A typical NMR spectrum, with up to 64k data points, of a complex biological fluid or an extract of cells and tissues consists of thousands of sharp signals that are mainly derived from small molecules. In addition, a number of advanced NMR spectroscopic methods are available for extracting information on high molecular weight compounds such as lipids or lipoproteins. There are numerous data preprocessing, data reduction, and analysis methods developed and evolving in the field of NMR metabolomics. Our goal is to provide an extensive summary of NMR data preprocessing and analysis strategies by providing examples and open source and commercially available analysis software and bioinformatics tools.

Clinical insights gained through metabolomic analysis of human breast milk

Introduction: Among the OMICS technologies, that have emerged in recent years, metabolomics has allowed relevant step forwards in clinical research. Several improvements in disease diagnosis and clinical management have been permitted, even in neonatology. Among potentially evaluable biofluids, breast milk (BM) results are highly interesting, representing a fluid of conjunction between mothers newborns, describing their interaction.Areas covered: in this review, updating a previous review article, we discuss research articles and reviews on BM metabolomics and found in MEDLINE using metabolomics, breast milk, neonatal nutrition, breastfeeding, human milk composition, and preterm neonates as keywords.Expert opinion: Our research group has a profound interest in metabolomics research. In 2012, we published the first metabolomic analysis on BM samples, reporting interesting data on its composition and relevant differences with formula milk (FM), useful to improve FM composition. As confirmed by successive studies, such technology can detect the specific BM composition and its dependence on several variables, including lactation stage, gestational age, maternal or environmental conditions. Moreover, since BM contaminants or drug levels can be detected, metabolomics also results useful to determine BM safety. These are only a few practical applications of BM analysis, which will be reviewed in this paper.

Improved Simple Sample Pretreatment Method for Quantitation of Major Human Milk Oligosaccharides Using Ultrahigh Pressure Liquid Chromatography with Fluorescence Detection

Human milk oligosaccharides (HMOs) maintain and promote infant health. Most of the current methods for HMOs quantitation require labor-intensive and time-consuming steps for sample preparation. This study presents two very simple and easy-to-operate pretreatment methods, requiring either ultrafiltration or centrifugation to separate free oligosaccharides from whole fat human milk and other milk matrix before oligosaccharides labeling for quantifying HMOs using ultrahigh pressure liquid chromatography with fluorescence detection. A single chromatography run quantified 15 sialylated and neutral HMOs with high sensitivity (with an LOD less than 8 pg for all HMOs tested: about 1 pg for 2'-fucosyllactose, 3-fucosyllactose, 4'-galactosyllactose, 3'-galactosyllactose, and 6'-galactosyllactose) and good linearity with coefficient of correlation above 0.999. Accuracy and precision were satisfactory for both pretreatment methods. Overall, the centrifugation pretreatment was efficient and reliable for samples with high levels of oligosaccharides, and the ultrafiltration pretreatment was especially suitable for samples with low oligosaccharide abundance.

Challenges and Pitfalls in Human Milk Oligosaccharide Analysis

Human milk oligosaccharides have been recognized as an important, functional biomolecule in mothers' milk. Moreover, these oligosaccharides have been recognized as the third most abundant component of human milk, ranging from 10-15 g/L in mature milk and up to and over 20 g/L reported in colostrum. Initially, health benefits of human milk oligosaccharides were assigned via observational studies on the differences between breastfed and bottle fed infants. Later, pools of milk oligosaccharides were isolated and used in functional studies and in recent years more specific studies into structure-function relationships have identified some advanced roles for milk oligosaccharides in the healthy development of infants. In other research, the levels, diversity, and complexity of human milk oligosaccharides have been studied, showing a wide variation in results. This review gives a critical overview of challenges in the analysis of human milk oligosaccharides. In view of the myriad functions that can be assigned, often to specific structures or classes of structures, it is very relevant to assess the levels of these structures in the human milk correctly, as well as in other biological sample materials. Ultimately, the review makes a case for a comparative, inter-laboratory study on quantitative human milk oligosaccharide analysis in all relevant biological samples.

NIH workshop on human milk composition: summary and visions

Nationally representative data from mother-child dyads that capture human milk composition (HMC) and associated health outcomes are important for advancing the evidence to inform federal nutrition and related health programs, policies, and consumer information across the governments in the United States and Canada as well as in nongovernment sectors. In response to identified gaps in knowledge, the National Institute of Diabetes and Digestive and Kidney Diseases of the NIH sponsored the "Workshop on Human Milk Composition-Biological, Environmental, Nutritional, and Methodological Considerations" held 16-17 November 2017 in Bethesda, Maryland. Through presentations and discussions, the workshop aimed to 1) share knowledge on the scientific need for data on HMC; 2) explore the current understanding of factors affecting HMC; 3) identify methodological challenges in human milk (HM) collection, storage, and analysis; and 4) develop a vision for a research program to develop an HMC data repository and database. The 4 workshop sessions included 1) perspectives from both federal agencies and nonfederal academic experts, articulating scientific needs for data on HMC that could lead to new research findings and programmatic advances to support public health; 2) information about the factors that influence lactation and/or HMC; 3) considerations for data quality, including addressing sampling strategies and the complexities in standardizing collection, storage, and analyses of HM; and 4) insights on how existing research programs and databases can inform potential visions for HMC initiatives. The general consensus from the workshop is that the limited scope of HM research initiatives has led to a lack of robust estimates of the composition and volume of HM consumed and, consequently, missed opportunities to improve maternal and infant health.

Fecal microbiome and metabolome of infants fed bovine MFGM supplemented formula or standard formula with breast-fed infants as reference: a randomized controlled trial

Human milk delivers an array of bioactive components that safeguard infant growth and development and maintain healthy gut microbiota. Milk fat globule membrane (MFGM) is a biologically functional fraction of milk increasingly linked to beneficial outcomes in infants through protection from pathogens, modulation of the immune system and improved neurodevelopment. In the present study, we characterized the fecal microbiome and metabolome of infants fed a bovine MFGM supplemented experimental formula (EF) and compared to infants fed standard formula (SF) and a breast-fed reference group. The impact of MFGM on the fecal microbiome was moderate; however, the fecal metabolome of EF-fed infants showed a significant reduction of several metabolites including lactate, succinate, amino acids and their derivatives from that of infants fed SF. Introduction of weaning food with either human milk or infant formula reduces the distinct characteristics of breast-fed- or formula-fed- like infant fecal microbiome and metabolome profiles. Our findings support the hypothesis that higher levels of protein in infant formula and the lack of human milk oligosaccharides promote a shift toward amino acid fermentation in the gut. MFGM may play a role in shaping gut microbial activity and function.

Validation and Application of Biocrates AbsoluteIDQ® p180 Targeted Metabolomics Kit Using Human Milk

Human-milk-targeted metabolomics analysis offers novel insights into milk composition and relationships with maternal and infant phenotypes and nutritional status. The Biocrates AbsoluteIDQ® p180 kit, targeting 40 acylcarnitines, 42 amino acids/biogenic amines, 91 phospholipids, 15 sphingolipids, and sum of hexoses, was evaluated for human milk using the AB Sciex 5500 QTRAP mass-spectrometer in liquid chromatography-tandem mass-spectrometry (LC-MS/MS) and flow-injection analysis (FIA) mode. Milk (<6 months lactation) from (A) Bangladeshi apparently healthy mothers (body mass index (BMI) > 18.5; n = 12) and (B) Bangladeshi mothers of stunted infants (height-for-age Z (HAZ)-score <-2; n = 13) was analyzed. Overall, 123 of the possible 188 metabolites were detected in milk. New internal standards and adjusted calibrator levels were used for improved precision and concentration ranges for milk metabolites. Recoveries ranged between 43% and 120% (coefficient of variation (CV): 2.4%-24.1%, 6 replicates). Milk consumed by stunted infants vs. that from mothers with BMI > 18.5 was lower in 6 amino acids/biogenic amines but higher in isovalerylcarnitine, two phospholipids, and one sphingomyelin (p < 0.05 for all). Associations between milk metabolites differed between groups. The AbsoluteIDQ® p180 kit is a rapid analysis tool suitable for human milk analysis and reduces analytical bias by allowing the same technique for different specimens. More research is needed to examine milk metabolite relationships with maternal and infant phenotypes.

Maternal obesity and the human milk metabolome: associations with infant body composition and postnatal weight gain

BACKGROUND

Maternal obesity is a risk factor for childhood obesity; this is a major public health concern given that ∼40% of pregnant women are either overweight or obese. Whether differences in milk composition in lean compared with obese women contribute to childhood obesity is unclear.

OBJECTIVES

We aimed to analyze relationships between maternal obesity and human milk metabolites, infant body composition, and postnatal weight gain.

METHODS

This was a prospective study in which mothers intending to breastfeed exclusively, and their newborn infants, were enrolled at delivery (n = 35 mother-infant pairs). We excluded mothers with diabetes, other medical conditions, or pregnancy complications. Participants were grouped by maternal prepregnancy BMI <25 (lean) or ≥25 kg/m2 (overweight/obese). We analyzed infant body composition by dual-energy X-ray absorptiometry and used untargeted liquid chromatography-gas chromatography-mass spectrometry to measure the milk content of 275 metabolites at 1 and 6 mo postpartum.

RESULTS

At 1 mo postpartum, 10 metabolites differed between overweight/obese and lean groups with nominal P < 0.05, but none was altered with a false discovery rate <0.25. Many differentially abundant metabolites belonged to the same chemical class; e.g., 4/10 metabolites were nucleotide derivatives, and 3/10 were human milk oligosaccharides. Milk adenine correlated positively with both continuously distributed maternal BMI and with infant adiposity and fat accrual. Analysis of milk composition at 6 mo postpartum revealed 20 differentially abundant metabolites (P < 0.05) in overweight/obese compared with lean women, including 6 metabolites with a false discovery rate of <0.25. At both 1 and 6 mo, human milk abundance of 1,5-anhydroglucitol, which has not previously been described in milk, was positively associated with maternal BMI.

CONCLUSIONS

Maternal obesity is associated with changes in the human milk metabolome. While only a subset of metabolites correlated with both maternal and infant weight, these point to potential milk-dependent mechanisms for mother-child transmission of obesity. This trial was registered at www.clinicaltrials.gov as NCT02535637.

Breaking the Glyco-Code of HIV Persistence and Immunopathogenesis

PURPOSE OF REVIEW

Glycoimmunology is an emerging field focused on understanding how immune responses are mediated by glycans (carbohydrates) and their interaction with glycan-binding proteins called lectins. How glycans influence immunological functions is increasingly well understood. In a parallel way, in the HIV field, it is increasingly understood how the host immune system controls HIV persistence and immunopathogenesis. However, what has mostly been overlooked, despite its potential for therapeutic applications, is the role that the host glycosylation machinery plays in modulating the persistence and immunopathogenesis of HIV. Here, we will survey four areas in which the links between glycan-lectin interactions and immunology and between immunology and HIV are well described. For each area, we will describe these links and then delineate the opportunities for the HIV field in investigating potential interactions between glycoimmunology and HIV persistence/immunopathogenesis.

RECENT FINDINGS

Recent studies show that the human glycome (the repertoire of human glycan structures) plays critical roles in driving or modulating several cellular processes and immunological functions that are central to maintaining HIV infection. Understanding the links between glycoimmunology and HIV infection may create a new paradigm for discovering novel glycan-based therapies that can lead to eradication, functional cure, or improved tolerance of lifelong infection.

A new dilution-enrichment sample preparation strategy for expanded metabolome monitoring of human breast milk that overcomes the simultaneous presence of low- and high-abundance lipid species

The complex nature of human breast milk (HBM) makes samples difficult to analyze, requiring several extraction techniques and analytical platforms to obtain high metabolome coverage. In this work, we combined liquid-liquid extraction (LLE) and solid-phase extraction (SPE) techniques to prepare HBM samples to overcome the challenge of low- and high-abundance lipid species, enabling the semiquantitative analysis of total HBM lipids in one liquid chromatography-mass spectrometry (LC-MS) run. A nonorganic fraction obtained during the LLE step was used to analyze small polar metabolites. This analytical approach allows extensive metabolome coverage, especially for low-abundance glycerophospholipids and sphingolipids. The method was applied to monitor short-term metabolome changes in HBM composition within individual mothers and the results showed variable metabolite composition patterns. Simultaneous detection of high-abundance glycerolipids and low-abundance but not less significant phospholipids in one LC-MS run saves time, decreases cost, and enables comprehensive insight into the dynamics of HBM composition.

Evidence of human milk oligosaccharides in maternal circulation already during pregnancy: a pilot study

Human milk oligosaccharides (HMOs) are bioactive glycans linked with health benefits to both the breast-fed infant and lactating mother. We hypothesized that HMOs are present before lactation, already during pregnancy, and are influenced by maternal body composition. In a pilot study, we investigated individual and temporal variations in HMO composition and concentration in maternal serum at gestational weeks 10-14 ( visit 1), 20-24 ( visit 2), and 30-35 (visit 3) (V1, V2, and V3, respectively) and associations with maternal body composition. HMOs were quantified by HPLC and confirmed by enzymatic digest and mass spectrometry. Associations of maternal prepregnancy body mass index (BMI), subcutaneous adipose tissue (SAT) thickness, and adipokines with absolute and relative HMO concentrations were analyzed by Spearman correlation. We identified 16 HMOs and 2 oligosaccharides not common to human milk. HMO concentration and composition varied with gestational age and secretor status. HMO concentration increased with gestational age and changed from a predominantly sialylated profile at V1 to a more balanced fucosylated-to-sialylated ratio at V3, mostly due to a profound increase in 2'-fucosyllactose (2'-FL), reflecting secretor phenotype. In secretor-positive women, BMI was negatively correlated with 2'-FL at V2. SAT at V1 and V2 were strongly negatively correlated with 2'-FL concentrations. This pilot study shows that prenatal HMOs are present in maternal serum, suggesting roles for HMOs already during pregnancy. Our result that maternal body composition is associated with prenatal HMOs might indicate that maternal metabolism modulates HMO composition with unknown implications for maternal and fetal health already during pregnancy.

The Profile of Human Milk Metabolome, Cytokines, and Antibodies in Inflammatory Bowel Diseases Versus Healthy Mothers, and Potential Impact on the Newborn

BACKGROUND AND AIMS

For women with inflammatory bowel disease [IBD], it is not very well known how IBD or IBD treatment affects their breast milk components. We aimed to investigate whether breast milk composition differs in healthy control [HC] versus IBD mothers in terms of antibodies, cytokines, and metabolite,s to identify potential impact of IBD breast milk on neonatal immune system.

METHODS

Breast milk specimens from HC [n = 17] and IBD [n = 31 for Crohn's disease [CD]; and n = 41 for ulcerative colitis [UC]; were collected at 3 and 6 months postpartum [PP3] and [PP6], respectively. Faecal samples were also collected. Cytokines and immunoglobulins [IgA/IgG/IgE] were analysed by multiplex Meso Scale Discovery [MSD] and commercial kits. Moreover, breast milk metabolites were analysed by 1H nuclear magnetic resonance [NMR].

RESULTS

We found that breast milk from IBD mothers showed significantly lower levels of IgA, sugar metabolite [lactose], and 2-aminobutyrate. In contrast, we observed that breast milk from mothers with IBD had increased levels of pro-inflammatory cytokines and higher energy metabolites [lactate and succinate] than milk from healthy mothers. In addition, we noticed that the type of treatment [5-aminosalicylic acid versus biologics] influenced the milk cytokines and metabolites profile.

CONCLUSIONS

The reduction in immunoprotective components of IBD breast milk such as sIgA and lactose theoretically may modulate the potential protective effects of breastfeeding. On the other hand, presence of higher levels of pro-inflammatory cytokines, lactate, and succinate may predispose the offspring to an inflammatory condition or impact on the gut microbiome. Better understanding of the role of succinate in infants and its potential effects on microbiome or mucosal immunity merits further investigations.

Sialylated Oligosaccharides and Glycoconjugates of Human Milk. The Impact on Infant and Newborn Protection, Development and Well-Being

Human milk not only has nutritional value, but also provides a wide range of biologically active molecules, which are adapted to meet the needs of newborns and infants. Mother’s milk is a source of sialylated oligosaccharides and glycans that are attached to proteins and lipids, whose concentrations and composition are unique. Sialylated human milk glycoconjugates and oligosaccharides enrich the newborn immature immune system and are crucial for their proper development and well-being. Some of the milk sialylated oligosaccharide structures can locally exert biologically active effects in the newborn’s and infant’s gut. Sialylated molecules of human milk can be recognized and bound by sialic acid-dependent pathogens and inhibit their adhesion to the epithelial cells of newborns and infants. A small amount of intact sialylated oligosaccharides can be absorbed from the intestine and remain in the newborn’s circulation in concentrations high enough to modulate the immunological system at the cellular level and facilitate proper brain development during infancy. Conclusion: The review summarizes the current state of knowledge on sialylated human milk oligosaccharides and glycoconjugates, discusses the significance of sialylated structures of human milk in newborn protection and development, and presents the advantages of human milk over infant formula.

Comparing patterns of volatile organic compounds exhaled in breath after consumption of two infant formulae with a different lipid structure: a randomized trial

Infant formulae have been used since decades as an alternative to or a complement to human milk. Human milk, the "gold standard" of infant nutrition, has been studied for its properties in order to create infant formulae that bring similar benefits to the infant. One of the characteristics of milk is the size of the lipid droplets which is known to affect the digestion, gastric emptying and triglyceride metabolism. In the current study a concept infant milk formula with large, phospholipid coating of lipid droplets (mode diameter 3-5 μm; NUTURIS, further described as "active"), was compared to a commercially available formula milk characterised by smaller lipid droplets, further described as "control" (both products derived from Nutricia). We investigated whether we could find an effect of lipid droplet size on volatile compounds in exhaled air upon ingestion of either product. For that purpose, exhaled breath was collected from a group of 29 healthy, non-smoking adult males before ingestion of a study product (baseline measurements, T0) and at the following time points after the test meal: 30, 60, 120, 180 and 240 min. Volatile organic compounds (VOCs) in breath were detected by gas chromatography-time-of-flight-mass spectrometry. Any differences in the time course of VOCs patterns upon intake of active and control products were investigated by regularised multivariate analysis of variance (rMANOVA). The rMANOVA analysis revealed statistically significant differences in the exhaled breath composition 240 min after ingestion of the active formula compared to control product (p-value < 0.0001), but did not show significant changes between active and control product at any earlier time points. A set of eight VOCs in exhaled breath had the highest contribution to the difference found at 240 minutes between the two formulas. A set of ten VOCs was different between baseline and the two formulae at T240 with p-value < 0.0001. To our knowledge this is the first study that shows the ability of VOCs in exhaled breath to monitor metabolic effects after ingestion of infant formulae with different lipid structure. The statistically significant differences in compound abundance found between active and control formula milk may be related to: (i) specific differences in the digestion, (ii) absorption of lipids and proteins and (iii) assimilation of the products in the gut.

Ontogeny of alkaline phosphatase activity in infant intestines and breast milk

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating disease of intestinal inflammation that primarily affects premature infants. A potential risk factor for necrotizing enterocolitis is exposure of the premature neonatal intestine to environmental bacteria and their proinflammatory products such as lipopolysaccharide. The metalloenzyme alkaline phosphatase (ALP) has been shown to reduce lipopolysaccharide-mediated inflammation. Additionally, premature rat pups have reduced alkaline phosphatase activity and expression as compared to full term pups. To explore the possibility that the human premature neonatal intestine has a paucity of alkaline phosphatase activity, we measured endogenously produced intestinal alkaline phosphatase activity in meconium as a function of gestational age. To test whether breast milk could serve as a source of exogenous alkaline phosphatase to the neonatal intestine through ingestion, we measured alkaline phosphatase activity in breast milk across a range of time points post-birth.

METHODS

Alkaline phosphatase activity was quantified in 122 meconium samples from infants of gestational ages ranging from 24 to 40 weeks and in 289 breast milk samples collected from 78 individual mothers between days 2-49 post-birth.

RESULTS

We observed a strong positive correlation between the meconium alkaline phosphatase activity and gestational age, with preterm infants having lower meconium alkaline phosphatase activities than early term or term infants. Breast milk alkaline phosphatase activity was highest in the first week post-birth, with peak alkaline phosphatase activity at day 2 post-birth, followed by relatively low alkaline phosphatase activity in weeks 2-7.

CONCLUSIONS

Our results are consistent with the two major risk factors for necrotizing enterocolitis development, preterm birth and lack of breast milk feeding, both contributing to a paucity of alkaline phosphatase activity and impaired capacity to detoxify proinflammatory bacterial products such as lipopolysaccharide.

Factors Influencing the Intestinal Microbiome During the First Year of Life

The intestinal microbiome plays a crucial role in the development of the immune system and regulation of immune responses. Many factors influence the composition of the infant intestinal microbiome and therefore the development and function of the immune system. This, in turn, may alter the risk of subsequent allergies, autoimmune diseases and other adverse health outcomes. Here, we review factors that influence the composition of the intestinal microbiome during the first year of life, including birth location, gestational age, delivery mode, feeding method, hospitalization, antibiotic or probiotic intake and living conditions. Understanding how the early intestinal microbiome is established and how this is perturbed provides many opportunities for interventions to improve health.

Metabolomics of Breast Milk: The Importance of Phenotypes

Breast milk is the gold standard of nutrition for newborns. Its composition is tailored to the nutritional needs of the infant and varies between mothers. In recent years, several bioactive molecules have been discovered in addition to the main nutrients, such as multipotent stem cells, hormones, immunoglobulins, and bacteria. Furthermore, the human milk oligosaccharides (HMOs) seem to exert several important protective biological functions. According to the HMOs’ composition, breast milk can be classified as a secretory or non-secretory phenotype. In our study, we investigated the metabolome of milk collected from 58 mothers that delivered neonates at term, that were appropriate, small or large for gestational age, by performing nuclear magnetic resonance spectroscopy (¹H-NMR). From the data analysis, two groups were distinguished based on their different types of oligosaccharides, and classified according the mother phenotype: secretory and non-secretory. This information is of major importance given the different biological function of the different HMOs, such as immune-modulation and protection against disease. This would allow us to predict whether the neonate would be, for instance, more prone to developing certain diseases, and to tailor her or his nutrition to fit their needs perfectly and pave the way to a personalized nutrition.

Compositional Dynamics of the Milk Fat Globule and Its Role in Infant Development

Human milk is uniquely optimized for the needs of the developing infant. Its composition is complex and dynamic, driven primarily by maternal genetics, and to a lesser extent by diet and environment. One important component that is gaining attention is the milk fat globule (MFG). The MFG is composed of a triglyceride-rich core surrounded by a tri-layer membrane, also known as the milk fat globule membrane (MFGM) that originates from mammary gland epithelia. The MFGM is enriched with glycerophospholipids, sphingolipids, cholesterol, and proteins, some of which are glycosylated, and are known to exert numerous biological roles. Mounting evidence suggests that the structure of the MFG and bioactive components of the MFGM may benefit the infant by aiding in the structural and functional maturation of the gut through the provision of essential nutrients and/or regulating various cellular events during infant growth and immune education. Further, antimicrobial peptides and surface carbohydrate moieties surrounding the MFG might have a pivotal role in shaping gut microbial populations, which in turn may promote protection against immune and inflammatory diseases early in life. This review seeks to: (1) understand the components of the MFG, as well as maternal factors including genetic and lifestyle factors that influence its characteristics; (2) examine the potential role of this milk component on the intestinal immune system; and (3) delineate the mechanistic roles of the MFG in infant intestinal maturation and establishment of the microbiota in the alimentary canal.

Human Breast Milk NMR Metabolomic Profile across Specific Geographical Locations and Its Association with the Milk Microbiota

The composition of human breast milk is highly variable, and it can be influenced by genetics, diet, lifestyle, and other environmental factors. This study aimed to investigate the impact of geographical location and mode of delivery on the nuclear magnetic resonance spectroscopy (NMR) metabolic profile of breast milk and its relationship with the milk microbiome. Human milk metabolic and microbiota profiles were determined using NMR and 16S rRNA gene sequencing, respectively, in 79 healthy women from Finland, Spain, South Africa, and China. Up to 68 metabolites, including amino acids, oligosaccharides, and fatty acid-associated metabolites, were identified in the milk NMR spectra. The metabolite profiles showed significant differences between geographical locations, with significant differences (p < 0.05) in the levels of galactose, lacto-N-fucopentaose III, lacto-N-fucopentaose I and 2-fucosyllactose, 3-fucosyllactose, lacto-N-difucohexaose II, lacto-N-fucopentaose III, 2-hydroxybutyrate, 3-hydroxybutyrate, proline, N-acetyl lysine, methyl-histidine, dimethylamine, kynurenine, urea, creatine and creatine phosphate, formate, lactate, acetate, phosphocholine, acetylcholine, LDL, VLDL, ethanolamine, riboflavin, hippurate, spermidine, spermine and uridine. Additionally, the effect of caesarean section on milk metabolome was dependent on the geographical region. Specific interrelations between human milk metabolites and microbiota were also identified. Proteobacteria, Actinobacteria, and Bacilli were most significantly associated with the milk metabolites, being either positively or negatively correlated depending on the metabolite. Our results reveal specific milk metabolomic profiles across geographical locations and also highlight the potential interactions between human milk’s metabolites and microbes.

Worldwide Variation in Human Milk Metabolome: Indicators of Breast Physiology and Maternal Lifestyle?

Human milk provides essential substrates for the optimal growth and development of a breastfed infant. Besides providing nutrients to the infant, human milk also contains metabolites which form an intricate system between maternal lifestyle, such as the mother's diet and the gut microbiome, and infant outcomes. This study investigates the variation of these human milk metabolites from five different countries. Human milk samples (n = 109) were collected one month postpartum from Australia, Japan, the USA, Norway, and South Africa and were analyzed by nuclear magnetic resonance. The partial least squares discriminant analysis (PLS-DA) showed separation between either maternal countries of origin or ethnicities. Variation between countries in concentration of metabolites, such as 2-oxoglutarate, creatine, and glutamine, in human milk, between countries, could provide insights into problems, such as mastitis and/or impaired functions of the mammary glands. Several important markers of milk production, such as lactose, betaine, creatine, glutamate, and glutamine, showed good correlation between each metabolite. This work highlights the importance of milk metabolites with respect to maternal lifestyle and the environment, and also provides the framework for future breastfeeding and microbiome studies in a global context.

Capillary Electrophoresis Analysis of Bovine Milk Oligosaccharides Permits an Assessment of the Influence of Diet and the Discovery of Nine Abundant Sulfated Analogues

Bovine milk oligosaccharides (BMOs), like their analogues in human milk, have important prebiotic functions. Environmental factors have previously been linked to variation in BMO structures, and thus to test the hypothesis that the bovine diet may lead to these changes in relative BMO abundances, a rapid capillary electrophoresis (CE)-based work flow was developed to profile the BMOs extracted from the milk of cows fed distinctly different diets. Over the first week of lactation, few significant differences were observed between the different diet groups, with the dominant changes being clearly linked to lactation period. CE analyses indicated the presence of ten unusually anionic BMOs, which were predicted to be phosphorylated and sulfated species. Nine unique sulfated BMOs were detected by high-resolution accurate mass spectrometry, none of which have been previously described in bovine milk. The biosynthesis of these was in direct competition with 3'-sialyllactose, the most abundant BMO in bovine milk.

RRR-α-Tocopherol Is the Predominant Stereoisomer of α-Tocopherol in Human Milk

BACKGROUND

The naturally occurring α-tocopherol (α-T) stereoisomer, RRR-α-tocopherol (RRR-α-T), is known to be more bioactive than all-rac-α-tocopherol (all-rac-α-T), a synthetic racemic mixture of 8 stereoisomers. There is widespread use of all-rac-α-T in maternal supplements.

OBJECTIVE

The aim of the study was to thoroughly describe the α-T stereoisomer profile of human milk.

METHODS

We measured the α-T stereoisomer profile in milk from 2 cohorts of women: a cohort of 121 women who provided milk on days 30 and 60 of lactation (study 1) and a separate cohort of 51 women who provided milk on days 10, 21, 71, and 120 of lactation (study 2).

RESULTS

RRR-α-T was the predominant stereoisomer (P < 0.0001) in all samples in both studies despite a large intrasubject range in total α-T (0.7-22 μg/mL). On average, RRR-α-T comprised 73-76% of total α-T, but average values for the synthetic stereoisomers were RRS, 8-14%; RSR, 6-8%; RSS, 5-6%; and the sum of 2S stereoisomers (Σ2S), 3-5%. Despite the predominance of RRR-α-T, the sum of the synthetic stereoisomers comprised as much as 48% of total α-T. We calculated the ratio of RRR to the sum of the synthetic 2R (RRS + RSR + RSS) stereoisomers (s2R) to assess the degree to which RRR is favored in milk. Consistent with discrimination among 2R stereoisomers in mammary tissue, RRR/s2R values ranged from 2.8 to 3.6, as opposed to the expected ratio of 0.33 if there was no discrimination. However, the RRR to s2R ratio did not correlate with milk α-T concentration, but both components of the ratio did.

CONCLUSIONS

RRR-α-T is the predominant stereoisomer in human milk, concentrations of synthetic 2R stereoisomers were notable, and the relation between milk total α-T and stereoisomer profile is complex. Due to the wide range found in milk α-T stereoisomer profile, investigation into its impact on α-T status and functional outcomes in breastfed infants is warranted.

Supplementation of Lactobacillus plantarum Improves Markers of Metabolic Dysfunction Induced by a High Fat Diet

Obesity is a prevalent chronic condition in many developed and developing nations that raises the risk for developing heart disease, stroke, and diabetes. Previous studies have shown that consuming particular probiotic strains of Lactobacillus is associated with improvement in the obese and diabetic phenotype; however, the mechanisms of these beneficial effects are not well understood. In this study, C57BL/6J male mice were fed a lard-based high fat diet for 15 weeks with Lactobacillus plantarum supplementation NCIMB8826 (Lp) between weeks 10 and 15 ( n = 10 per group). Systemic metabolic effects of supplementation were analyzed by NMR metabolomics, protein expression assays, gene transcript quantification, and 16S rRNA marker gene sequencing. Body and organ weights were not significantly different with Lp supplementation, and no microbiota community structure changes were observed in the cecum; however, L. plantarum numbers were increased in the treatment group according to culture-based and 16S rRNA gene quantification. Significant differences in metabolite and protein concentrations (serum, liver, and colon), gene expression (ileum and adipose), and cytokines (colon) were observed between groups with increases in the gene expression of tight junction proteins in the ileum and cecum and improvement of some markers of glucose homeostasis in blood and tissue with Lp supplementation. These results indicate Lp supplementation impacts systemic metabolism and immune signaling before phenotypic changes and without large-scale changes to the microbiome. This study supports the notion that Lp is a beneficial probiotic, even in the context of a high fat diet.

Effects of triclosan in breast milk on the infant fecal microbiome

Triclosan is frequently used for its antimicrobial properties and has been detected in human serum, urine, and breast milk. Animal and molecular studies have shown that triclosan exerts a wide range of adverse health effects at both high (ppm) and low (ppb) concentrations. Since triclosan is of growing concern to human and environmental health, there is a need to improve extraction procedures and to study additional effects from triclosan exposure. In this study, we have improved triclosan extraction from breast milk by using salt (MgSO4) to reduce emulsion formation and increase water polarity and water (∼80%) to enhance the overall extraction efficiency (∼3.5 fold). This extraction method was applied to breast milk samples collected from donors who i) recorded their use of triclosan-containing personal care products and ii) provided matching infant stool samples. Of the participants who had detectable amounts of triclosan in their breast milk, nine (75%) of them reported daily use of triclosan-containing personal care products. Levels of triclosan in breast milk were compared to the donor's infant's fecal microbiome. We found that the bacterial diversity in the fecal microbiome of the infants exposed to breast milk with detectable triclosan levels differed compared to their peers exposed to milk containing non-detectable amounts. This finding implies that exogenous chemicals are impacting microbiome diversity.

Micronutrients in Human Milk: Analytical Methods

Exclusive breastfeeding is recommended by the WHO for the first 6 mo of life because human milk protects against gastrointestinal infections and supplies balanced and adequate nutrient contents to the infant. However, reliable data on micronutrient concentrations in human milk are sparse, especially because some micronutrients are affected by maternal diet. Microbiological and competitive protein-binding assays, nuclear magnetic resonance or inductively coupled plasma spectroscopy, and chromatographic analyses are among the methods that have been applied to human-milk micronutrient analysis. However, the validation or evaluation of analytical methods in terms of their suitability for the complex human-milk matrix has been commonly ignored in reports, even though the human-milk matrix differs vastly from blood, plasma, or urine matrixes. Thus, information on the validity, accuracy, and sensitivity of the methods is essential for the estimation of infant and maternal intake requirements to support and maintain adequate milk micronutrient concentrations for healthy infant growth and development. In this review, we summarize current knowledge on methods used for analyzing water- and fat-soluble vitamins as well as iron, copper, zinc, iodine, and selenium in human milk and their different forms in milk; the tools available for quality control and assurance; and guidance for preanalytical considerations. Finally, we recommend preferred methodologic approaches for analysis of specific milk micronutrients.

Metabolic phenotyping of malnutrition during the first 1000 days of life

Nutritional restrictions during the first 1000 days of life can impair or delay the physical and cognitive development of the individual and have long-term consequences for their health. Metabolic phenotyping (metabolomics/metabonomics) simultaneously measures a diverse range of low molecular weight metabolites in a sample providing a comprehensive assessment of the individual's biochemical status. There are a growing number of studies applying such approaches to characterize the metabolic derangements induced by various forms of early-life malnutrition. This includes acute and chronic undernutrition and specific micronutrient deficiencies. Collectively, these studies highlight the diverse and dynamic metabolic disruptions resulting from various forms of nutritional deficiencies. Perturbations were observed in many pathways including those involved in energy, amino acid, and bile acid metabolism, the metabolic interactions between the gut microbiota and the host, and changes in metabolites associated with gut health. The information gleaned from such studies provides novel insights into the mechanisms linking malnutrition with developmental impairments and assists in the elucidation of candidate biomarkers to identify individuals at risk of developmental shortfalls. As the metabolic profile represents a snapshot of the biochemical status of an individual at a given time, there is great potential to use this information to tailor interventional strategies specifically to the metabolic needs of the individual.

Exocrine pancreas glutamate secretion help to sustain enterocyte nutritional needs under protein restriction

Glutamine (Gln) is the most concentrated amino acid in blood and considered conditionally essential. Its requirement is increased during physiological stress, such as malnutrition or illness, despite its production by muscle and other organs. In the malnourished state, Gln has been suggested to have a trophic effect on the exocrine pancreas and small intestine. However, the Gln transport capacity, the functional relationship of these two organs, and the potential role of the Gln-glutamate (Glu) cycle are unknown. We observed that pancreatic acinar cells express lower levels of Glu than Gln transporters. Consistent with this expression pattern, the rate of Glu influx into acinar cells was approximately sixfold lower than that of Gln. During protein restriction, acinar cell glutaminase expression was increased and Gln accumulation was maintained. Moreover, Glu secretion by acinar cells into pancreatic juice and thus into the lumen of the small intestine was maintained. In the intestinal lumen, Glu absorption was preserved and Glu dehydrogenase expression was augmented, potentially providing the substrates for increasing energy production via the TCA cycle. Our findings suggest that one mechanism by which Gln exerts a positive effect on exocrine pancreas and small intestine involves the Gln metabolism in acinar cells and the secretion of Glu into the small intestine lumen. The exocrine pancreas acinar cells not only avidly accumulate Gln but metabolize Gln to generate energy and to synthesize Glu for secretion in the pancreatic juice. Secreted Glu is suggested to play an important role during malnourishment in sustaining small intestinal homeostasis. NEW & NOTEWORTHY Glutamine (Gln) has been suggested to have a trophic effect on exocrine pancreas and small intestine in malnourished states, but the mechanism is unknown. In this study, we suggest that this trophic effect derives from an interorgan relationship between exocrine pancreas and small intestine for Gln-glutamate (Glu) utilization involving the uptake and metabolism of Gln in acinar cells and secretion of Glu into the lumen of the small intestine.

Toxicological evaluation of 6'-sialyllactose (6'-SL) sodium salt

We performed a series of toxicity studies on the safety of 6'-sialyllactose (6'-SL) sodium salt as a food ingredient. 6'-SL sodium salt, up to a maximum dose of 5000 μg/plate, did not increase the number of revertant colonies in five strains of Salmonella typhimurium in the presence or absence of S9 metabolic activation. A chromosomal aberration assay (using Chinese hamster lung cells) found no clastogenic effects at any concentration of 6'-SL sodium salt in the presence or absence of S9 metabolic activation. An in vivo bone marrow micronucleus test in Kunming mice showed no clastogenic activities with 6'-SL sodium salt doses up to 2000 mg/kg body weight (bw). In an acute toxicity study, the mean lethal dose of 6'-SL sodium salt was greater than 20 g/kg bw in rats. In a 13-week subchronic toxicity investigation, no effects were found at doses up to 5.0 g/kg bw of 6'-SL sodium salt in food consumption, body weight, clinical signs, blood biochemistry and hematology, urinalysis, or ophthalmic and histological macroscopic examination of organs. The no-observed-adverse-effect level (NOAEL) was 5.0 g/kg bw/day in rats.

Phytochemicals in Human Milk and Their Potential Antioxidative Protection

Diets contain secondary plant metabolites commonly referred to as phytochemicals. Many of them are believed to impact human health through various mechanisms, including protection against oxidative stress and inflammation, and decreased risks of developing chronic diseases. For mothers and other people, phytochemical intake occurs through the consumption of foods such as fruits, vegetables, and grains. Research has shown that some these phytochemicals are present in the mother’s milk and can contribute to its oxidative stability. For infants, human milk (HM) represents the primary and preferred source of nutrition because it is a complete food. Studies have reported that the benefit provided by HM goes beyond basic nutrition. It can, for example, reduce oxidative stress in infants, thereby reducing the risk of lung and intestinal diseases in infants. This paper summarizes the phytochemicals present in HM and their potential contribution to infant health.

Composition and Variation of Macronutrients, Immune Proteins, and Human Milk Oligosaccharides in Human Milk From Nonprofit and Commercial Milk Banks

BACKGROUND

When human milk is unavailable, banked milk is recommended for feeding premature infants. Milk banks use processes to eliminate pathogens; however, variability among methods exists. Research aim: The aim of this study was to compare the macronutrient (protein, carbohydrate, fat, energy), immune-protective protein, and human milk oligosaccharide (HMO) content of human milk from three independent milk banks that use pasteurization (Holder vs. vat techniques) or retort sterilization.

METHODS

Randomly acquired human milk samples from three different milk banks ( n = 3 from each bank) were analyzed for macronutrient concentrations using a Fourier transform mid-infrared spectroscopy human milk analyzer. The concentrations of IgA, IgM, IgG, lactoferrin, lysozyme, α-lactalbumin, α antitrypsin, casein, and HMO were analyzed by mass spectrometry.

RESULTS

The concentrations of protein and fat were significantly ( p < .05) less in the retort sterilized compared with the Holder and vat pasteurized samples, respectively. The concentrations of all immune-modulating proteins were significantly ( p < .05) less in the retort sterilized samples compared with vat and/or Holder pasteurized samples. The total HMO concentration and HMOs containing fucose, sialic acid, and nonfucosylated neutral sugars were significantly ( p < .05) less in retort sterilized compared with Holder pasteurized samples.

CONCLUSION

Random milk samples that had undergone retort sterilization had significantly less immune-protective proteins and total and specific HMOs compared with samples that had undergone Holder and vat pasteurization. These data suggest that further analysis of the effect of retort sterilization on human milk components is needed prior to widespread adoption of this process.

Systematic review of the concentrations of oligosaccharides in human milk

Context

Oligosaccharides are the third largest solid component in human milk. These diverse compounds are thought to have numerous beneficial functions in infants, including protection against infectious diseases. The structures of more than 100 oligosaccharides in human milk have been elucidated so far.

Objective

The aim of this review was to identify the main factors that affect the concentrations of oligosaccharides in human milk and to determine whether it is possible to calculate representative and reliable mean concentrations.

Data Sources

A comprehensive literature search on oligosaccharide concentrations in human milk was performed in 6 electronic databases: BIOSIS, Current Contents Search, Embase, Lancet Titles, MEDLINE and PubMed.

Study Selection

The initial search resulted in 1363 hits. After the elimination of duplicates, the literature was screened. The application of strict inclusion criteria resulted in 21 articles selected.

Data Extraction

Oligosaccharide concentrations, both mean values and single values, reported in the literature were sorted by gestational age, secretor status of mothers, and defined lactation periods.

Results

Mean concentrations, including confidence limits, of 33 neutral and acidic oligosaccharides reported could be calculated. Concentrations of oligosaccharides in human milk show variations that are dependent on both the secretor type of the mother and the lactation period as examined by analyses of variance. In addition, large interlaboratory variations in the data were observed.

Conclusions

Worldwide interlaboratory quantitative analyses of identical milk samples would be required to identify the most reliable methods of determining concentrations of oligosaccharides in human milk. The data presented here contribute to the current knowledge about the composition and quantities of oligosaccharides in human milk and may foster greater understanding of the biological functions of these compounds.

Human Breast Milk: Exploring the Linking Ring Among Emerging Components

Maternal breast milk (BM) is a complex and unique fluid that evolution adapted to satisfy neonatal needs; in addition to classical nutrients, it contains several bioactive components. BM characteristically shows inter-individual variability, modifying its composition during different phases of lactation. BM composition, determining important consequences on neonatal gut colonization, influences both short and long-term development. Maternal milk can also shape neonatal microbiota, through its glycobiome rich in Lactobacilli spp. and Bifidobacteria spp. Therefore, neonatal nourishment during the first months of life seems the most important determinant of individual's outcomes. Our manuscript aims to provide new evidence in the characterization of BM metabolome and microbiome, and its comparison to formula milk, allowing the evaluation of each nutrient's influence on neonatal metabolism. This result very interesting since potentially offers an innovative approach to investigate the complex relationship between BM components and infant's health, also providing the chance to intervene in a sartorial way on diet composition, according to the nutritional requests. Future research, integrating metabolomics, microbiomics and stem cells knowledge, could make significant steps forward in understanding BM extraordinary properties and functions.

Effect of high-fat diet on secreted milk transcriptome in midlactation mice

High-fat diet (HFD) during lactation alters milk composition and is associated with development of metabolic diseases in the offspring. We hypothesized that HFD affects milk microRNA (miRNA) and mRNA content, which potentially impact offspring development. Our objective was to determine the effect of maternal HFD on secreted milk transcriptome. To meet this objective, 4 wk old female ICR mice were divided into two treatments: control diet containing 10% kcal fat and HFD containing 60% kcal fat. After 4 wk on CD or HFD, mice were bred while continuously fed the same diets. On postnatal day 2 (P2), litters were normalized to 10 pups, and half the pups in each litter were cross-fostered between treatments. Milk was collected from dams on P10 and P12. Total RNA was isolated from milk fat fraction of P10 samples and used for mRNA-Seq and small RNA-Seq. P12 milk was used to determine macronutrient composition. After 4 wk of prepregnancy feeding HFD mice weighed significantly more than did the control mice. Lactose and fat concentration were significantly ( P < 0.05) higher in milk of HFD dams. Pup weight was significantly greater ( P < 0.05) in groups suckled by HFD vs. control dams. There were 25 miRNA and over 1,500 mRNA differentially expressed (DE) in milk of HFD vs. control dams. DE mRNA and target genes of DE miRNA enriched categories that were primarily related to multicellular organismal development. Maternal HFD impacts mRNA and miRNA content of milk, if bioactive nucleic acids are absorbed by neonate differences may affect development.

Prebiotics Mediate Microbial Interactions in a Consortium of the Infant Gut Microbiome

Composition of the gut microbiome is influenced by diet. Milk or formula oligosaccharides act as prebiotics, bioactives that promote the growth of beneficial gut microbes. The influence of prebiotics on microbial interactions is not well understood. Here we investigated the transformation of prebiotics by a consortium of four representative species of the infant gut microbiome, and how their interactions changed with dietary substrates. First, we optimized a culture medium resembling certain infant gut parameters. A consortium containing Bifidobacterium longum subsp. infantis, Bacteroides vulgatus, Escherichia coli and Lactobacillus acidophilus was grown on fructooligosaccharides (FOS) or 2′-fucosyllactose (2FL) in mono- or co-culture. While Bi. infantis and Ba. vulgatus dominated growth on 2FL, their combined growth was reduced. Besides, interaction coefficients indicated strong competition, especially on FOS. While FOS was rapidly consumed by the consortium, B. infantis was the only microbe displaying significant consumption of 2FL. Acid production by the consortium resembled the metabolism of microorganisms dominating growth in each substrate. Finally, the consortium was tested in a bioreactor, observing similar predominance but more pronounced acid production and substrate consumption. This study indicates that the chemical nature of prebiotics modulate microbial interactions in a consortium of infant gut species.

Microbiota, metabolome, and immune alterations in obese mice fed a high-fat diet containing type 2 resistant starch

SCOPE

We examined the intestinal and systemic responses to incorporating a type 2 resistant starch (RS) into a high fat diet fed to obese mice.

METHODS AND RESULTS

Diet-induced obese, C57BL/6J male mice were fed an HF diet without or with 20% (by weight) high-amylose maize resistant starch (HF-RS) for 6 weeks. Serum adiponectin levels were higher with RS consumption, but there were no differences in weight gain and adiposity. With HF-RS, the expression levels of ileal TLR2 and Reg3g and cecal occludin, TLR2, TLR4, NOD1 and NOD2 were induced; whereas colonic concentrations of the inflammatory cytokine IL-17A declined. The intestinal, serum, liver, and urinary metabolomes were also altered. HF-RS resulted in lower amino acid concentrations, including lower serum branched chain amino acids, and increased quantities of urinary di/trimethylamine, 3-indoxylsulfate, and phenylacetylglycine. Corresponding to these changes were enrichments in Bacteroidetes (S24-7 family) and certain Firmicutes taxa (Lactobacillales and Erysipelotrichaceae) with the HF-RS diet. Parabacteroides and S24-7 positively associated with cecal maltose concentrations. These taxa and Erysipelotrichaceae, Allobaculum, and Bifidobacterium were directly correlated with uremic metabolites.

CONCLUSION

Consumption of RS modified the intestinal microbiota, stimulated intestinal immunity and endocrine-responses, and modified systemic metabolomes in obese mice consuming an otherwise obesogenic diet.

Human milk oligosaccharides and infant gut bifidobacteria: Molecular strategies for their utilization

Breast milk is the gold standard in infant nutrition. In addition to provide essential nutrients for the newborn, it contains multiple bioactive molecules that provide protection and stimulate proper development. Human milk oligosaccharides (HMO) are complex carbohydrates abundant in breast milk. Intriguingly, these molecules do not provide energy to the infant. Instead, these oligosaccharides are key to guide and support the assembly of a healthy gut microbiome in the infant, dominated by beneficial gut microbes such as Bifidobacterium. New analytical methods for glycan analysis, and next-generation sequencing of microbial communities, have been instrumental in advancing our understanding of the positive role of breast milk oligosaccharides on the gut microbiome, and the genomics and molecular strategies of Bifidobacterium to utilize these oligosaccharides. Moreover, novel approaches to simulate the impact of HMO on the gut microbiome have been described and successfully validated, including the incorporation of synthetic HMO and bovine milk oligosaccharides to infant formula. This review discusses recent advances regarding the influence of HMO in promoting a healthy gut microbiome, with emphasis in the molecular basis of the enrichment in beneficial Bifidobacterium, and novel approaches to replicate the effect of HMO using synthetic or bovine oligosaccharides.

Evolution of Newborns' Urinary Metabolomic Profiles According to Age and Growth

Improving the management of neonatal diseases and prevention of chronic diseases in adulthood requires a better comprehension of the complex maturational processes associated with newborns' development. Urine-based metabolomic studies play a promising role in the fields of pediatrics and neonatology, relying on simple and noninvasive collection procedures while integrating a variety of factors such as genotype, nutritional state, lifestyle, and diseases. Here, we investigate the influence of age, weight, height, and gender on the urine metabolome during the first 4 months of life. Untargeted analysis of urine was carried out by ¹H-Nuclear Magnetic Resonance (NMR) spectroscopy for 90 newborns under 4 months of age, and free of metabolic, nephrologic, or urologic diseases. Supervised multivariate statistical analysis of the metabolic profiles revealed metabolites significantly associated with age, weight, and height, respectively. The tremendous growth occurring during the neonatal period is associated with specific modifications of newborns' metabolism. Conversely, gender appears to have no impact on the urine metabolome during early infancy. These results allow a deeper understanding of newborns' metabolic maturation and underline potential confounding factors in newborns' metabolomics studies. We emphasize the need to systematically and precisely report children age, height, and weight that impact urine metabolic profiles of infants.

Human Milk and Allergic Diseases: An Unsolved Puzzle

There is conflicting evidence on the protective role of breastfeeding in relation to the development of allergic sensitisation and allergic disease. Studies vary in methodology and definition of outcomes, which lead to considerable heterogeneity. Human milk composition varies both within and between individuals, which may partially explain conflicting data. It is known that human milk composition is very complex and contains variable levels of immune active molecules, oligosaccharides, metabolites, vitamins and other nutrients and microbial content. Existing evidence suggests that modulation of human breast milk composition has potential for preventing allergic diseases in early life. In this review, we discuss associations between breastfeeding/human milk composition and allergy development.

"Omics" in Human Colostrum and Mature Milk: Looking to Old Data with New Eyes

Human Milk (HM) is the best source for newborn nutrition until at least six months; it exerts anti-inflammatory and anti-infective functions, promotes immune system formation and supports organ development. Breastfeeding could also protect from obesity, diabetes and cardiovascular disease. Furthermore, human colostrum (HC) presents a peculiar role in newborn support as a protective effect against allergic and chronic diseases, in addition to long-term metabolic benefits. In this review, we discuss the recent literature regarding "omics" technologies and growth factors (GF) in HC and the effects of pasteurization on its composition. Our aim was to provide new evidence in terms of transcriptomics, proteomics, metabolomics, and microbiomics, also in relation to maternal metabolic diseases and/or fetal anomalies and to underline the functions of GF. Since HC results are so precious, particularly for the vulnerable pre-terms category, we also discuss the importance of HM pasteurization to ensure donated HC even to neonates whose mothers are unable to provide. To the best of our knowledge, this is the first review analyzing in detail the molecular pattern, microbiota, bioactive factors, and dynamic profile of HC, finding clinical correlations of such mediators with their possible in vivo effects and with the consequent impact on neonatal outcomes.

Relationships Among Microbial Communities, Maternal Cells, Oligosaccharides, and Macronutrients in Human Milk

BACKGROUND

Human milk provides all essential nutrients necessary for early life and is rich in nonnutrients, maternally derived (host) cells, and bacteria, but almost nothing is known about the interplay among these components. Research aim: The primary objective of this research was to characterize relationships among macronutrients, maternal cells, and bacteria in milk.

METHODS

Milk samples were collected from 16 women and analyzed for protein, lipid, fatty acid, lactose, and human milk oligosaccharide concentrations. Concentrations of maternal cells were determined using microscopy, and somatic cell counts were enumerated. Microbial ecologies were characterized using culture-independent methods.

RESULTS

Absolute and relative concentrations of maternal cells were mostly consistent within each woman as were relative abundances of bacterial genera, and there were many apparent relationships between these factors. For instance, relative abundance of Serratia was negatively associated with somatic cell counts ( r = -.47, p < .0001) and neutrophil concentration ( r = -.38, p < .0006). Concentrations of several oligosaccharides were correlated with maternally derived cell types as well as somatic cell counts; for example, lacto-N-tetraose and lacto-N-neotetraose were inversely correlated with somatic cell counts ( r = -.64, p = .0082; r = -.52, p = .0387, respectively), and relative abundance of Staphylococcus was positively associated with total oligosaccharide concentration ( r = .69, p = .0034). Complex relationships between milk nutrients and bacterial community profile, maternal cells, and milk oligosaccharides were also apparent.

CONCLUSION

These data support the possibility that profiles of maternally derived cells, nutrient concentrations, and the microbiome of human milk might be interrelated.

Postprandial metabolic response of breast-fed infants and infants fed lactose-free vs regular infant formula: A randomized controlled trial

Lactose intolerance is a major concern driving the growth of lactose-free foods including lactose-free infant formula. It is unknown what the metabolic consequence is of consumption of a formula where lactose has been replaced with corn syrup solids (CSS). Here, a randomized double-blinded intervention study was conducted where exclusively formula-fed infants were fed formula containing either lactose or CSS-based infant formula and compared with an equal number of exclusively breast-fed infants. Plasma metabolites and insulin were measured at baseline, 15, 30, 60, 90 and 120 min after feeding. Differences in plasma metabolite profiles for formula-fed infants included a rapid increase in circulating amino acids, creatinine and urea compared with breast-fed infants. At 120 min post-feeding, insulin was significantly elevated in formula-fed compared with breast-fed infants. Infants fed lactose-based formula had the highest levels of glucose at 120 min, and leucine, isoleucine, valine and proline at 90 and 120 min, whereas infants fed CSS-based formula had the lowest levels of non-esterified fatty acids at all time points, and glucose at 120 min. Overall, these differences highlight that changes in infant formula composition impact infant metabolism, and show that metabolomics is a powerful tool to help with development of improved infant formulas.

Composition of human breast milk in acute kidney injury

BACKGROUND

Breastfeeding is a widely encouraged practice due to its benefits for mother and the infant. Little is known about the impact of disease states, such as kidney dysfunction and childbirth complications, on the composition of breast milk.

METHODS

We describe a case of a 35-year-old woman who suffered a postpartum hemorrhage, was administered a contrast dye prior to computer tomography, and developed an acute kidney injury. Using nuclear magnetic resonance spectrometry, we measured composition of milk in acute kidney injury. The amount of dye secreted into milk was determined using a spectroscopic assay.

RESULTS

Here we show that acute kidney injury results in changes in milk composition, but it does not significantly affect major macronutrients. We also determine that iodinated computer tomography contrast dye does not accumulate in milk in appreciable amounts.

CONCLUSION

Acute kidney injury has impact on breast milk. Intravenous administration of computer tomography contrast dye does not result in significantly elevated levels in milk.