Human milk oligosaccharide composition predicts risk of necrotising enterocolitis in preterm infants

Necrotizing enterocolitis: specific human milk oligosaccharides prevent enteric glia loss and hypomotility

BACKGROUND

Necrotizing enterocolitis (NEC) is mediated by toll-like receptor 4 (TLR4)-induced inflammation and is preceded by reduced intestinal motility. Human milk oligosaccharides (HMOs) are non-digestible components of breast milk that prevent NEC in preclinical models. We now hypothesize that HMOs can reduce the risk of NEC through restoration of intestinal motility and reduced TLR4-mediated inflammation.

METHODS

NEC was induced in C57-BL/6 mice through the combination of formula gavage, hypoxia, and oral administration of NEC stool. Mice were administered either 2'-FL (5 g/L), 6'-SL (5 g/L), or a blend of 5 specific HMOs (5 g/L) containing 2'-FL (2.606 g/L), 3'-FL (0.652 g/L), LNT (1.304 g/L), 3'-SL (0.174 g/L), and 6'-SL (0.260 g/L). Gastrointestinal motility was assessed by 70 Kd FITC-dextran transit time. Enteric glia were quantified by immunohistochemistry and qRT-PCR expression.

RESULTS

Administration of either 2'-FL, 6'-SL, or HMO blend significantly attenuated NEC severity and reversed intestinal hypomotility. HMOs prevented enteric glia loss and regulated key genes critical for enteric glia maintenance, attenuated pro-apoptotic genes, and increased anti-apoptotic genes in vitro, resulting in a reduction in apoptosis. Strikingly, HMOs reduced LPS-TLR4-induced NFκB signaling and ROS generation in enteric glia.

CONCLUSIONS

HMOs protect against NEC at least in part through protective effects on inflammation and the enteric nervous system.

IMPACT

This study sheds light on the role of certain human milk oligosaccharides in a clinically relevant mouse model of NEC and adds additional insights into their underlying mechanism of action by revealing a protective effect on the enteric nervous system. These results reveal that HMOs prevent the loss of enteric glia in NEC and influence the expression of genes that regulate enteric glia maintenance. HMOs also limit TLR4-NFkB signaling, providing an additional mechanism of enteric glia maintenance.

Human milk oligosaccharides improve white matter and interneuron development in a double-hit rat model for preterm brain injury

Mother's own milk is the preferred source of nutrition for preterm infants due to its beneficial compounds, including human milk oligosaccharides (HMOs). HMOs support microbiota and immune development, but their effect on the preterm brain remains unstudied. Here, we examined the therapeutic potential of HMOs and short-chain galacto- and long-chain fructo-oligosaccharides (scGOS/lcFOS) in a preclinical model for encephalopathy of prematurity. Pregnant Wistar rats were injected with 10 μg/kg lipopolysaccharides at embryonic day 20, and pups were exposed to hypoxia (8% O2, 140 min) at postnatal day (P)4 (fetal inflammation and postnatal hypoxia; FIPH). From P1, FIPH-pups of both sexes were treated intragastrically with HMOs, scGOS/lcFOS (9:1), or water. Transcriptomic analysis of CD11b/c + microglia was performed at P6, while immunohistochemical, microbial and short-chain fatty acid (SCFA) analyses were performed at P20. Decreased cortical myelin in FIPH animals was rescued exclusively by HMOs. Furthermore, both HMOs and scGOS/lcFOS treatments normalized reduced parvalbumin+ interneuron numbers in the hippocampus, potentially through promoting beneficial bacteria, including Lactobacillus and Bifidobacterium, and cecal acetic acid content. Interestingly, treatment with HMOs more effectively restored FIPH-induced upregulation of microglial genes associated with immune activation and normalized persistent activated microglial morphology in FIPH-males. HMOs supplementation holds promise to improve neurodevelopmental outcomes following preterm birth.

Human Milk Oligosaccharides Modulating Inflammation in Infants, Adults, and Older Individuals-From Concepts to Applications

The increasing global prevalence of inflammatory diseases, such as ulcerative colitis and irritable bowel syndrome, represents a challenging task for healthcare systems. Several approaches to disease management target the intestinal microbiome, which plays a key role in health and disease. One promising approach is modulating the microbiome using human milk oligosaccharides (HMOs). Originating from human milk, HMOs are indigestible carbohydrates that act in a host-optimized prebiotic fashion by providing an energy source for health-promoting intestinal bacteria and exhibiting systemic effects. Commercial products supporting infant health and development have been the primary fields of HMO application. Advancements in the large-scale production of HMOs through bioengineering and precision fermentation have led to evaluation of their potential for managing inflammatory diseases. Several in vitro studies and observations on model systems have been clinically validated in infants, resulting in a large body of evidence supporting the safety and efficacy of HMOs in inflammatory disorders. Although novel approaches seek to explore interventions in adults, the primary goal for the future is to provide cost-efficient, safe, and reliable healthcare compounds across all age groups.

Donor human milk pasteurization methods and the effect on milk components as they relate to Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is an intestinal disease that predominantly occurs in preterm infants. While there are no definitive treatment options for NEC, the administration of human milk is protective against the development of NEC in preterm infants. However, human milk composition is highly dynamic, containing numerous bioactive components that can be affected by both maternal and perinatal factors. Furthermore, when maternal milk is unavailable, donor human milk, which goes through a rigorous preparation process including pooling and pasteurization, is used. The different pasteurization methods can have implications for the bioactive components of human milk. In this review, we explore the current literature surrounding the benefits of human milk in the prevention of NEC. We further review the bioactive components and the microbiome of human milk and the many factors that affect the diversity of milk content between human milk samples. Finally, we review the different methods of pasteurization and their effects on the components of human milk.

Dietary nucleotides drive changes in infant fecal microbiota in vitro and gut microbiota-gut-brain development in neonatal rats: A potential "nitrogen source" for early microbiota growth

Various dietary factors in human milk are important nutrients for the formation of the infant gut microbiota (GM). While promoting the growth of the GM, some human milk components that are difficult to absorb and utilize will be broken down by the GM, and converted into nutrients that the baby can use, such as breast milk oligosaccharides-the 'carbon source' for infant GM. This study reveals that nucleotides (NTs), significant non-protein nitrogen sources in human milk, can enhance the abundance of beneficial microbial genera such as g_Bifidobacterium, g_Bacteroides, and g_Blautia in in vitro fecal fermentation fluids of infants at low doses (2 mg/mL). Conversely, high doses of NTs (20 mg/mL) increased the abundance of g_Escherichia-Shigella. Furthermore, low-dose NTs fermentation broth significantly enhanced the expression of neurodevelopmental marker genes such as Tuj1, Sox2, Dcx, and NeuN in NE-4C neural stem cells, whereas a single NTs digestion broth did not exhibit significant activity. However, in vivo studies using neonatal rats as a model demonstrated that both low-dose NTs fermentation broth and NTs digestive juices promoted behavioral development in neonatal rats (PND 20) and neuron maturation in the prefrontal cortex and hippocampus. Non-targeted metabolomics results indicate that low-dose dietary NTs promote the production of certain neuroregulatory metabolites in infant fecal fermentation, such as uridine, L-tyrosine, L-glutamic acid, and succinic acid. These findings suggest that NTs may serve as an important "nitrogen source" during GM formation in early life and have a dose effect in driving the development of the microbiota-gut-brain axis in early life.

Profiles of 71 Human Milk Oligosaccharides and Novel Sub-Clusters of Type I Milk: Results from the Ulm SPATZ Health Study

BACKGROUND/OBJECTIVES

Although approximately 160 human milk oligosaccharides (HMOs) have been identified, current studies on HMO quantitation are limited to the 10-19 most abundant HMOs. We assessed the variations in the relative concentrations of 71 HMO structures over lactation in human milk samples by an advanced liquid chromatography-mass spectrometry approach.

METHODS

Samples were collected from 64 mothers at 6 weeks, 6 months, and 12 months of lactation in the Ulm SPATZ Health Study, a German birth cohort. In this longitudinal study, we fitted linear mixed-effect models to analyze changes in the log2-transformed and standardized HMO concentration over time. Based on the profile of 71 HMOs, we also fitted a group-based multi-trajectory (GBMT) model to cluster mothers secreting cluster type I milk, who account for the majority of lactating mothers.

RESULTS

We found that 52 HMOs had a decreasing trend (regression coefficients ranging from -1.41 to -0.17) and 9 had an increasing trend (regression coefficients ranging from 0.25 to 0.64) during lactation, and the findings were statistically significant after multiple testing corrections. Using human milk samples of 49 mothers with type I milk, we further identified two novel sub-clusters with distinct longitudinal trajectories of concentrations of 71 HMOs during lactation: Type I-a (N = 20) and I-b (N = 29). These sub-clusters were not associated with maternal non-genetic characteristics.

CONCLUSIONS

Our findings extend existing knowledge about the structural diversity of HMOs and their variations over lactation. These may pave the way to investigate the potential nutritional benefits of various HMOs on infant health and early life development in the future.

Interactions of human milk oligosaccharides with the immune system

Human milk oligosaccharides (HMOs) are abundant, diverse and complex sugars present in human breast milk. HMOs are well-characterized barriers to microbial infection and by modulating the human microbiome they are also thought to be nutritionally beneficial to the infant. The structural variety of over 200 HMOs, including neutral, fucosylated and sialylated forms, allows them to interact with the immune system in various ways. Clinically, HMOs impact allergic diseases, reducing autoimmune and inflammatory responses, and offer beneficial support to the preterm infant immune health. This review examines the HMO composition and associated immunomodulatory effects, including interactions with immune cell receptors and gut-associated immune responses. These immunomodulatory properties highlight the potential for HMO use in early stage immune development and for use as novel immunotherapeutics. HMO research is rapidly evolving and promises innovative treatments for immune-related conditions and improved health outcomes.

Free oligosaccharides in serum

Glycans are sugars/sugar chains that are usually linked to proteins or lipids. The attachment of glycans often results in alterations of physicochemical/physiological properties of the carrier molecules, e.g., glycosylation of proteins can modulate their fate, intracellular localization, or interaction with cells/other proteins. On the other hand, unconjugated N-glycans (free N-glycans; FNGs) have been identified in the cytosol of eukaryotic cells. The processing pathway of intracellular FNGs has been clarified in recent years, but their biological functions remain unclear. Free oligosaccharides have also been identified in the sera of various animals. Structurally, these extracellular free glycans can be classified into three types: sialyl FNGs, oligomannose-type FNGs, and sialyl lactose/N-acetyllactosamine-type glycans. The extracellular FNGs show different structural features from intracellular FNGs, implying that their mechanism of formation is distinct. This mini-review summarizes current knowledge about the structures and formation mechanisms of free oligosaccharides in serum, and suggests their possible biological functions.

Human Milk Oligosaccharides: Decoding Their Structural Variability, Health Benefits, and the Evolution of Infant Nutrition

Human milk oligosaccharides (HMOs), the third most abundant solid component in human milk, vary significantly among women due to factors such as secretor status, race, geography, season, maternal nutrition and weight, gestational age, and delivery method. In recent studies, HMOs have been shown to have a variety of functional roles in the development of infants. Because HMOs are not digested by infants, they act as metabolic substrates for certain bacteria, helping to establish the infant's gut microbiota. By encouraging the growth of advantageous intestinal bacteria, these sugars function as prebiotics and produce short-chain fatty acids (SCFAs), which are essential for gut health. HMOs can also specifically reduce harmful microbes and viruses binding to the gut epithelium, preventing illness. HMO addition to infant formula is safe and promotes healthy development, infection prevention, and microbiota. Current infant formulas frequently contain oligosaccharides (OSs) that differ structurally from those found in human milk, making it unlikely that they would reproduce the unique effects of HMOs. However, there is a growing trend in producing OSs resembling HMOs, but limited data make it unclear whether HMOs offer additional therapeutic benefits compared to non-human OSs. Better knowledge of how the human mammary gland synthesizes HMOs could direct the development of technologies that yield a broad variety of complex HMOs with OS compositions that closely mimic human milk. This review explores HMOs' complex nature and vital role in infant health, examining maternal variation in HMO composition and its contributing factors. It highlights recent technological advances enabling large-scale studies on HMO composition and its effects on infant health. Furthermore, HMOs' multifunctional roles in biological processes such as infection prevention, brain development, and gut microbiota and immune response regulation are investigated. The structural distinctions between HMOs and other mammalian OSs in infant formulas are discussed, with a focus on the trend toward producing more precise replicas of HMOs found in human milk.

Enzymatic Synthesis of Disialyllacto-N-Tetraose (DSLNT) and Related Human Milk Oligosaccharides Reveals Broad Siglec Recognition of the Atypical Neu5Acα2-6GlcNAc Motif

Sialic acids (Sias) are ubiquitously expressed on all types of glycans, typically as terminating residues. They usually link to galactose, N-acetylgalactosamine, or other Sia residues, forming ligands of many glycan-binding proteins. An atypical linkage to the C6 of N-acetylglucosamine (GlcNAc) has been identified in human milk oligosaccharides (HMOs, e.g., DSLNT) and tumor-associated glycoconjugates. Herein, describe the systematic synthesis of these HMOs in an enzymatic modular manner. The synthetic strategy relies on a novel activity of ST6GalNAc6 for efficient construction of the Neu5Acα2-6GlcNAc linkage, and another 12 specific enzyme modules for sequential HMO assembly. The structures enabled comprehensive exploration of their structure-function relationships using glycan microarrays, revealing broad yet distinct recognition by Siglecs of the atypical Neu5Acα2-6GlcNAc motif. The work provides tools and new insight for the functional study and potential applications of Siglecs and HMOs.

Comprehensive Targeted and Quantitative Profiling of the Human Milk Metabolome: Impact of Delivery Mode, Breastfeeding Practices, and Maternal Diet

SCOPE

Human milk (HM) is rich in bioactive compounds and essential nutrients. While research has focused on lipids, minerals, immune markers, microbiota, and oligosaccharides, specific metabolites are less studied. This study uses targeted metabolomics to identify and quantify metabolites in HM and explores the impact of perinatal and dietary factors on the metabolomic profile.

METHODS AND RESULTS

In a cross-sectional study of 123 healthy lactating women, HM samples were collected up to 1 month postpartum and analyzed using the Biocrates MxP Quant 500 kit. Maternal and neonatal clinical, anthropometric, and nutritional data were collected. A total of 432 metabolites were quantified and categorized into 20 groups. The metabolomic profiles formed three distinct clusters, primarily driven by triglyceride concentration differences. Docosahexaenoic acid (DHA) levels were higher in HM from mothers with vaginal delivery compared to C-section births and differences in hexoses were found between exclusive and mixed-feeding practices. Maternal diets rich in lipids and animal proteins were associated with elevated amino acids, sphingolipids, and glycosyl-ceramides.

CONCLUSION

The HM metabolome was grouped into three clusters influenced by delivery mode, lactation practices, and maternal diet. This comprehensive analysis opens new avenues to explore HM composition and offers valuable insights for future dietary interventions aimed at modulating HM.

Role of Human Milk Microbiota in Infant Neurodevelopment: Mechanisms and Clinical Implications

BACKGROUND

Human milk (HM) is recognized as an ideal source of nutrition for newborns; as a result, its multiple bioactive molecules can support the growth of healthy newborns and reduce the risk of mortality and diseases such as asthma, respiratory infections, diabetes (type 1 and 2), and gastrointestinal disorders such as ulcerative colitis and Crohn's disease. Furthermore, it can reduce the severity of necrotizing enterocolitis (NEC) in preterm infants. Moreover, human milk oligosaccharides (HMOs) present in breast milk show an immunomodulatory, prebiotic, and neurodevelopmental effect that supports the microbiota-gut-brain axis.

MATERIAL AND METHODS

This study examined the state-of-the-art research, using keywords such as "breastfeeding", "human milk oligosaccharides", "microbiota-gut-brain axis", "infants", and "malnutrition". The literature review was conducted by selecting articles between 2013 and 2024, as the most recent ones. The databases used were Web Science, PubMed, and Scopus.

RESULTS

We found multiple studies examining the composition of HM and infant formula (IF). However, further longitudinal studies and randomized control trials (RCTs) are needed to better understand the clinical outcomes that bioactive components exert on healthy and hospitalized children and how, in conditions of malnutrition, it is necessary to support the growth of the newborn.

CONCLUSIONS

In this review, we affirm the importance of human milk and, through it, the modulation of the microbiota and the neuroprotective role in newborns, determining the health of the following years of life.

Biological effects of combinations of structurally diverse human milk oligosaccharides

Human milk oligosaccharides (HMOs) are a diverse group of structures and an abundant bioactive component of breastmilk that contribute to infant health and development. Preclinical studies indicate roles for HMOs in shaping the infant gut microbiota, inhibiting pathogens, modulating the immune system, and influencing cognitive development. In the past decade, several industrially produced HMOs have become available to fortify infant formula. Clinical intervention trials with manufactured HMOs have begun to corroborate some of the physiological effects reported in preclinical studies, especially modulation of the gut microbiota in the direction of breastfed infants. As more HMOs become commercially available and as HMOs have some shared mechanisms of action, there is a need to better understand the unique and differential effects of individual HMOs and the benefits of combining multiple HMOs. This review focuses on the differential effects of different HMO structural classes and individual structures and presents a scientific rationale for why combining multiple structurally diverse HMOs is expected to exert greater biological effects.

Human milk microbiota, oligosaccharide profiles, and infant gut microbiome in preterm infants diagnosed with necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe intestinal disease of very preterm infants with mother's own milk (MOM) providing protection, but the contribution of the MOM microbiota to NEC risk has not been explored. Here, we analyze MOM of 110 preterm infants (48 NEC, 62 control) in a cross-sectional study. Breast milk contains viable bacteria, but there is no significant difference in MOM microbiota between NEC and controls. Integrative analysis between MOM microbiota, human milk oligosaccharides (HMOs), and the infant gut microbiota shows positive correlations only between Acinetobacter in the infant gut and Acinetobacter and Staphylococcus in MOM. This study suggests that NEC protection from MOM is not modulated through the MOM microbiota. Thus, "'restoring" the MOM microbiota in donor human milk is unlikely to reduce NEC, and emphasis should instead focus on increasing fresh maternal human milk intake and researching different therapies for NEC prevention.

A comparative study of the substrate preference of the sialidases, CpNanI, HpNanH, and BbSia2 towards 2-Aminobenzamide-labeled 3'-Sialyllactose, 6'-Sialyllactose, and Sialyllacto-N-tetraose-b

Sialidases catalyze the removal of terminal sialic acids from sialylated biomolecules, and their substrate preference is frequently indicated in terms of the glycosidic linkages cleaved (α2-3, α2-6, and α2-8) without mention of the remaining sub-terminal reducing-end saccharide moieties. Many human gut commensal and pathogenic bacteria secrete sialidases to forage for sialic acids, which are then utilized as an energy source or assimilated into membrane/capsular structural components. Infant gut commensals similarly utilize sialylated human milk oligosaccharides containing different glycosidic linkages. Here, we have studied the preference of the bacterial sialidases, BbSia2 from Bifidobacterium bifidum, CpNanI from Clostridium perfringens, and HpNanH from Glaesserella parasuis, for the glycosidic linkages, Siaα2-3Gal, Siaα2-6Gal, and Siaα2-6GlcNAc, by employing 2-Aminobenzamide-labeled human milk oligosaccharides, 3'-Sialyllactose (3'-SL), 6'-Sialyllactose (6'-SL), and Sialyllacto-N-tetraose-b (LSTb), respectively, as proxies for these glycosidic linkages. BbSia2, CpNanI, and HpNanH hydrolyzed these three oligosaccharides with the glycosidic linkage preferences, 3'-SL (Siaα2-3Gal) ≥ LSTb (Siaα2-6GlcNAc) ≥ 6'-SL (Siaα2-6Gal), 3'-SL (Siaα2-3Gal) ≥ 6'-SL (Siaα2-6Gal) > LSTb (Siaα2-6GlcNAc), and 3'-SL (Siaα2-3Gal) ≥ 6'-SL (Siaα2-6Gal) > LSTb (Siaα2-6GlcNAc), respectively. Our finding suggests that sub-terminal reducing-end saccharide moieties can profoundly influence the substrate preference of sialidases, and advocates for the characterization and indication of the substrate preference of sialidases in terms of both the glycosidic linkage and the sub-terminal reducing-end saccharide moiety.

Effects of multistrain Bifidobacteria and Lactobacillus probiotics on HMO compositions after supplementation to pregnant women at threatening preterm delivery: design of the randomized clinical PROMO trial

BACKGROUND

As an indigestible component of human breast milk, Human Milk Oligosaccharides (HMOs) play an important role as a substrate for the establishing microbiome of the newborn. They have further been shown to have beneficial effects on the immune system, lung and brain development. For preterm infants HMO composition of human breast milk may be of particular relevance since the establishment of a healthy microbiome is challenged by multiple disruptive factors associated with preterm birth, such as cesarean section, hospital environment and perinatal antibiotic exposure. In a previous study it has been proposed that maternal probiotic supplementation during late stages of pregnancy may change the HMO composition in human milk. However, there is currently no study on pregnancies which are threatened to preterm birth. Furthermore, HMO composition has not been investigated in association with clinically relevant outcomes of vulnerable infants including inflammation-mediated diseases such as sepsis, necrotizing enterocolitis (NEC) or chronic lung disease.

MAIN BODY

A randomized controlled intervention study (PROMO = probiotics for human milk oligosaccharides) has been designed to analyze changes in HMO composition of human breast milk after supplementation of probiotics (Lactobacillus acidophilus, Bifidobacterium lactis and Bifidobacterium infantis) in pregnancies at risk for preterm birth. The primary endpoint is HMO composition of 3-fucosyllactose and 3'-sialyllactose in expressed breast milk. We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. As secondary outcomes we will measure preterm infants' clinical outcomes (preterm birth, sepsis, weight gain growth, gastrointestinal complications) and effects on microbiome composition in the rectovaginal tract of mothers at delivery and in the gut of term and preterm infants by sequencing at high genomic resolution. Therefore, we will longitudinally collect bio samples in the first 4 weeks after birth as well as in follow-up investigations at 3 months, one year, and five years of age.

CONCLUSIONS

We estimate that probiotic intervention will increase these two HMO levels by 50% according to the standardized mean difference between treatment and control groups. The PROMO study will gain insight into the microbiome-HMO interaction at the fetomaternal interface and its consequences for duration of pregnancy and outcome of infants.

Human Milk Oligosaccharides in Antenatal Colostrum: A Case Study

Introduction/Background: Some women produce antenatal colostrum during pregnancy and feed it to their baby after birth. However, the composition of antenatal colostrum and how it compares to postnatal colostrum and mature milk are not well described. In fact, there are currently no data on the composition of antenatal colostrum when it comes to human milk oligosaccharides (HMOs), the third most abundant solid human milk component after lactose and lipids. Case Presentation: We report a case of a single healthy donor who collected antenatal colostrum and urine from 19 weeks of gestation all the way to mature milk at 3 months postpartum. We analyzed all samples for HMO composition using high-performance liquid chromatography and for lactose concentrations using an enzymatic assay. Results: The entire spectrum of HMOs typical of a nonsecretor was already present in antenatal colostrum at 19 weeks gestation with a total concentration of 7.5 mg/mL. The HMO concentration further increased to over 12.5 mg/mL at 30 weeks gestation and then declined throughout the remainder of pregnancy and continued to decline in the postpartum period with concentrations of less than 5 mg/mL at 12 weeks postpartum. Concentrations of some of the individual HMOs as well as lactose changed significantly at the time of birth. HMO composition in antenatal colostrum was different in time-matched urine samples. Conclusion: Measuring HMOs in maternal urine does not fully capture the composition of HMOs in antenatal colostrum. Feeding antenatal colostrum to the newborn baby provides the entire set of different HMOs at high concentrations.

Characterization and application of active human α2,6-sialyltransferases ST6GalNAc V and ST6GalNAc VI recombined in Escherichia coli

Eukaryotic sialyltransferases play key roles in many physiological and pathological events. The expression of active human recombinant sialyltransferases in bacteria is still challenging. In the current study, the genes encoding human N-acetylgalactosaminide α2,6-sialyltransferase V (hST6GalNAc V) and N-acetylgalactosaminide α2,6-sialyltransferase VI (hST6GalNAc VI) lacking the N-terminal transmembrane domains were cloned into the expression vectors, pET-32a and pET-22b, respectively. Soluble and active forms of recombinant hST6GalNAc V and hST6GalNAc VI when coexpressed with the chaperone plasmid pGro7 were successfully achieved in Escherichia coli. Further, lactose (Lac), Lacto-N-triose II (LNT II), lacto-N-tetraose (LNT), and sialyllacto-N-tetraose a (LSTa) were used as acceptor substrates to investigate their activities and substrate specificities. Unexpectedly, both can transfer sialic acid onto all those substrates. Compared with hST6GalNAc V expressed in the mammalian cells, the recombinant two α2,6-sialyltransferases in bacteria displayed flexible substrate specificities and lower enzymatic efficiency. In addition, an important human milk oligosaccharide disialyllacto-N-tetraose (DSLNT) can be synthesized by both human α2,6-sialyltransferases expressed in E. coli using LSTa as an acceptor substrate. To the best of our knowledge, these two active human α2,6-sialyltransferases enzymes were expressed in bacteria for the first time. They showed a high potential to be applied in biotechnology and investigating the molecular mechanisms of biological and pathological interactions related to sialylated glycoconjugates.

Human Milk Oligosaccharides, Growth, and Body Composition in Very Preterm Infants

Human milk oligosaccharides (HMOs) are bioactive factors that benefit neonatal health, but little is known about effects on growth in very preterm infants (<32 weeks' gestation). We aimed to quantify HMO concentrations in human milk fed to very preterm infants during the neonatal hospitalization and investigate associations of HMOs with infant size and body composition at term-equivalent age. In 82 human-milk-fed very preterm infants, we measured HMO concentrations at two time points. We measured anthropometrics and body composition with air displacement plethysmography at term-equivalent age. We calculated means of individual and total HMOs, constructed tertiles of mean HMO concentrations, and assessed differences in outcomes comparing infants in the highest and intermediate tertiles with the lowest tertile using linear mixed effects models, adjusted for potential confounders. The mean (SD) infant gestational age was 28.2 (2.2) weeks, and birthweight was 1063 (386) grams. Exposure to the highest (vs. lowest) tertile of HMO concentrations was not associated with anthropometric or body composition z-scores at term-corrected age. Exposure to the intermediate (vs. lowest) tertile of 3FL was associated with a greater head circumference z-score (0.61, 95% CI 0.15, 1.07). Overall, the results do not support that higher HMO intakes influence growth outcomes in this very preterm cohort.

Recent Progress in Human Milk Oligosaccharides and Its Antiviral Efficacy

Gastrointestinal (GI)-associated viruses, including rotavirus (RV), norovirus (NV), and enterovirus, usually invade host cells, transmit, and mutate their genetic information, resulting in influenza-like symptoms, acute gastroenteritis, encephalitis, or even death. The unique structures of human milk oligosaccharides (HMOs) enable them to shape the gut microbial diversity and endogenous immune system of human infants. Growing evidence suggests that HMOs can enhance host resistance to GI-associated viruses but without a systematic summary to review the mechanism. The present review examines the lactose- and neutral-core HMOs and their antiviral effects in the host. The potential negative impacts of enterovirus 71 (EV-A71) and other GI viruses on children are extensive and include neurological sequelae, neurodevelopmental retardation, and cognitive decline. However, the differences in the binding affinity of HMOs for GI viruses are vast. Hence, elucidating the mechanisms and positive effects of HMOs against different viruses may facilitate the development of novel HMO derived oligosaccharides.

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.

Rat hepatocytes secrete free oligosaccharides

We recently established a method for the isolation of serum-free oligosaccharides, and characterized various features of their structures. However, the precise mechanism for how these glycans are formed still remains unclarified. To further investigate the mechanism responsible for these serum glycans, here, we utilized rat primary hepatocytes to examine whether they are able to secrete free glycans. Our findings indicated that a diverse array of free oligosaccharides such as sialyl/neutral free N-glycans (FNGs), as well as sialyl lactose/LacNAc-type glycans, were secreted into the culture medium by primary hepatocytes. The structural features of these free glycans in the medium were similar to those isolated from the sera of the same rat. Further evidence suggested that an oligosaccharyltransferase is involved in the release of the serum-free N-glycans. Our results indicate that the liver is indeed secreting various types of free glycans directly into the serum.

Monitoring the Use of Human Milk, the Ideal Food for Very Low-Birth-Weight Infants-A Narrative Review

Aware of the utmost importance of feeding premature babies-especially those of lower weight-with human milk, as well as the need to monitor this important element of neonatal care, we focused on four aspects in this review. First of all, we reviewed the beneficial effects of feeding premature infants with breast milk in the short and long term. Secondly, we performed a quantitative evaluation of the rates of breastfeeding and feeding with human milk in Very-Low-Birth-Weight infants (VLBWs) during hospitalization in the Neonatal Intensive Care Unit (NICU) and at discharge. Our aim was to take a snapshot of the current status of human milk-feeding care and track its trends over time. Then we analyzed, on the one hand, factors that have been proven to facilitate the use of maternal milk and, on the other hand, the risk factors of not feeding with breast milk. We also considered the spread of human milk banking so as to assess the availability of donated milk for the most vulnerable category of premature babies. Finally, we proposed a protocol designed as a tool for the systematic monitoring of actions that could be planned and implemented in NICUs in order to achieve the goal of feeding even more VLBWs with human milk.

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.

A bacterial sialidase mediates early-life colonization by a pioneering gut commensal

The early microbial colonization of the gastrointestinal tract can have long-term impacts on development and health. Keystone species, including Bacteroides spp., are prominent in early life and play crucial roles in maintaining the structure of the intestinal ecosystem. However, the process by which a resilient community is curated during early life remains inadequately understood. Here, we show that a single sialidase, NanH, in Bacteroides fragilis mediates stable occupancy of the intestinal mucosa in early life and regulates a commensal colonization program. This program is triggered by sialylated glycans, including those found in human milk oligosaccharides and intestinal mucus. NanH is required for vertical transmission from dams to pups and promotes B. fragilis dominance during early life. Furthermore, NanH facilitates commensal resilience and recovery after antibiotic treatment in a defined microbial community. Collectively, our study reveals a co-evolutionary mechanism between the host and microbiota mediated through host-derived glycans to promote stable colonization.

Where does the time go? Temporal patterns of pumping behaviors in mothers of very preterm infants vary by sociodemographic and clinical factors

Background

Mothers of very preterm (<32 weeks gestational age [GA]) infants are breast pump dependent and have shorter duration of milk provision than mothers of term infants. The opportunity (i.e., time) cost of pumping and transporting mother's own milk (MOM) from home to the NICU may be a barrier. There is a paucity of data regarding how much time mothers actually spend pumping.

Objective

To investigate the variation in pumping behavior by postpartum week, maternal characteristics, and infant GA.

Methods

Prospectively collected pump log data from mothers enrolled in ReDiMOM (Reducing Disparity in Mother's Own Milk) randomized, controlled trial included pumping date and start time and end time of each pumping session for the first 10 weeks postpartum or until the infant was discharged from the NICU, whichever occurred first. Outcomes included number of daily pumping sessions, number of minutes spent pumping per day, and pumping behaviors during 24-h periods, aggregated to the postpartum week. Medians (interquartile ranges) were used to describe outcomes overall, and by maternal characteristics and infant GA.

Results

Data included 13,994 pump sessions from 75 mothers. Maternal characteristics included 55% Black, 35% Hispanic, and 11% White and 44% <30 years old. The majority (56%) of infants were born at GA 28-31 weeks. Mothers pumped an average of less than 4 times per day, peaking in postpartum week 2. After accounting for mothers who stopped pumping, there was a gradual decrease in daily pumping minutes between postpartum weeks 2 (89 min) and 10 (46 min). Black mothers pumped fewer times daily than non-Black mothers after the first 2 weeks postpartum.

Conclusion

On average mothers pumped less intensively than the minimum recommendation of 8 times and 100 min per day. However, these pumping behaviors represent significant maternal opportunity costs that should be valued by the institution and society at large.

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.

Gut microbiome derived short chain fatty acids: Promising strategies in necrotising enterocolitis

Necrotising enterocolitis (NEC) is a devastating condition that poses a significant risk of morbidity and mortality, particularly among preterm babies. Extensive research efforts have been directed at identifying optimal treatment and diagnostic strategies but results from such studies remain unclear and controversial. Among the most promising candidates are prebiotics, probiotics and their metabolites, including short chain fatty acids (SCFAs). Such metabolites have been widely explored as possible biomarkers of gut health for different clinical conditions, with overall positive effects on the host observed. This review aims to describe the role of gut microbiome derived SCFAs in necrotising enterocolitis. Until now, information has been conflicting, with the primary focus on the main three SCFAs (acetic acid, propionic acid, and butyric acid). While numerous studies have indicated the relationship between SCFAs and NEC, the current evidence is insufficient to draw definitive conclusions about the use of these metabolites as NEC biomarkers or their potential in treatment strategies. Ongoing research in this area will help enhance both our understanding of SCFAs as valuable indicators of NEC and their practical application in clinical settings.

Human milk-derived MANF, as an immuno-nutritional factor, maintains the intestinal epithelial barrier and protects against necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a leading cause of death in preterm infants. Compared to formula milk, breastfeeding protects against NEC. However, the composition of breast milk is quite complicated, and many immunological compositions remain unknown. In this study, we aimed to investigate the concentration of a secreted protein, Mesencephalic astrocyte-derived neurotrophic factor (MANF), in breastmilk and evaluate its immune-regulatory function in protecting the intestinal epithelial barrier. Our data indicated that MANF was secreted in human milk but could not be detected in infant formulas. More importantly, the amount of MANF in colostrum was higher than that in mature milk. We also clarified that MANF was mainly expressed in intestinal macrophages and was capable of inducing apoptosis and decreasing the inflammation of pro-inflammatory macrophages in both NEC intestinal tissues and BMDMs. Mechanismly, MANF protein significantly inhibited the apoptosis of intestinal epithelial cells and protected epithelial tight junctions through downregulation of the NF-κB pathway in pro-inflammatory macrophages. These results reveal the crucial function of human milk-derived MANF in intestinal macrophages, which contributes to downregulating the intestinal inflammatory response and protecting the homeostasis of intestinal epithelial cells. Our study not only demonstrates a potential mechanism underlying breastfeeding protective effects in NEC but also, more importantly, enables clinical translation, facilitating new strategies for the development of nutritional interventions in the prevention of NEC.

Human Milk Oligosaccharides: A Critical Review on Structure, Preparation, Their Potential as a Food Bioactive Component, and Future Perspectives

Human milk is the gold standard for infant feeding. Human milk oligosaccharides (HMOs) are a unique group of oligosaccharides in human milk. Great interest in HMOs has grown in recent years due to their positive effects on various aspects of infant health. HMOs provide various physiologic functions, including establishing a balanced infant's gut microbiota, strengthening the gastrointestinal barrier, preventing infections, and potential support to the immune system. However, the clinical application of HMOs is challenging due to their specificity to human milk and the difficulties and high costs associated with their isolation and synthesis. Here, the differences in oligosaccharides in human and other mammalian milk are compared, and the synthetic strategies to access HMOs are summarized. Additionally, the potential use and molecular mechanisms of HMOs as a new food bioactive component in different diseases, such as infection, necrotizing enterocolitis, diabetes, and allergy, are critically reviewed. Finally, the current challenges and prospects of HMOs in basic research and application are discussed.

Review and Perspectives on Bifidobacterium lactis for Infants' and Children's Health

The influence of microbiota dysbiosis in early life is increasingly recognized as a risk factor for the development of several chronic diseases later in life, including an increased risk of asthma, eczema, allergies, obesity, and neurodevelopmental disorders. The question whether the potential lifelong consequences of early life dysbiosis could be mitigated by restoring microbiota composition remains unresolved. However, the current evidence base suggests that protecting the normal development of the microbiome during this critical developmental window could represent a valuable public health strategy to curb the incidence of chronic and lifestyle-related diseases. Probiotic Bifidobacteria are likely candidates for this purpose in newborns and infants considering the natural dominance of this genus on microbiota composition in early life. Moreover, the most frequently reported microbiota composition alteration in association with newborn and infant diseases, including necrotizing enterocolitis and diarrhea, is a reduction in Bifidobacteria levels. Several studies have assessed the effects of B. animalis subsp. lactis strains in newborns and infants, but recent expert opinions recommend analyzing their efficacy at the strain-specific level. Hence, using the B94 strain as an example, this review summarizes the clinical evidence available in infants and children in various indications, discussing the safety and potential modes of actions while providing perspectives on the concept of "non-infant-type" probiotics for infants' health.

Prebiotics in New-Born and Children's Health

At present, prebiotics, like probiotics, are receiving more attention as a promising tool for health maintenance. Many studies have recognized the role of prebiotics in preventing and treating various illnesses including metabolic disorders, gastrointestinal disorders, and allergies. Naturally, prebiotics are introduced to the human body in the first few hours of life as the mother breastfeeds the newborn. Prebiotic human milk oligosaccharides (HMOs) are the third largest constituent of human breastmilk. Studies have proven that HMOs modulate an infant's microbial composition and assist in the development of the immune system. Due to some health conditions of the mother or beyond the recommended age for breastfeeding, infants are fed with formula. Few types of prebiotics have been incorporated into formula to yield similar beneficial impacts similar to breastfeeding. Synthetic HMOs have successfully mimicked the bifidogenic effects of breastmilk. However, studies on the effectiveness and safety of consumption of these synthetic HMOs are highly needed before massive commercial production. With the introduction of solid foods after breastfeeding or formula feeding, children are exposed to a range of prebiotics that contribute to further shaping and maturing their gut microbiomes and gastrointestinal function. Therefore, this review evaluates the functional role of prebiotic interventions in improving microbial compositions, allergies, and functional gastrointestinal disorders in children.

Biological Relevance of Goat Milk Oligosaccharides to Infant Health

Milk is often regarded as the gold standard for the nourishment of all mammalian offspring. The World Health Organization (WHO) recommends exclusive breastfeeding for the first 6 months of the life of the infant, followed by a slow introduction of complementary foods to the breastfeeding routine for a period of approximately 2 years, whenever this is possible ( Global Strategy for Infant and Young Child Feeding; WHO, 2003). One of the most abundant components in all mammals' milk, which is associated with important health benefits, is the oligosaccharides. The milk oligosaccharides (MOS) of humans and other mammals differ in terms of their concentration and diversity. Among those, goat milk contains more oligosaccharides (gMOS) than other domesticated dairy animals, as well as a greater range of structures. This review summarizes the biological functions of MOS found in both human and goat milk to identify the possible biological relevance of gMOS in human health and development. Based on the existing literature, seven biological functions of gMOS were identified, namely, MOS action as prebiotics, immune modulators, and pathogen traps; their modulation of intestinal cells; protective effect against necrotizing enterocolitis; improved brain development; and positive effects on stressor exposure. Overall, goat milk is a viable alternate supply of functional MOS that could be employed in a newborn formula.

A dual-binding magnetic immunoassay to predict spontaneous preterm birth

Complications posed by preterm birth (delivery before 37 weeks of pregnancy) are a leading cause of newborn morbidity and mortality. The previous discovery and validation of an algorithm that includes maternal serum protein biomarkers, sex hormone-binding globulin (SHBG), and insulin-like growth factor-binding protein 4 (IBP4), with clinical factors to predict preterm birth represents an opportunity for the development of a widely accessible point-of-care assay to guide clinical management. Toward this end, we developed SHBG and IBP4 quantification assays for maternal serum using giant magnetoresistive (GMR) sensors and a self-normalizing dual-binding magnetic immunoassay. The assays have a picomolar limit of detections (LOD) with a relatively broad dynamic range that covers the physiological level of the analytes as they change throughout gestation. Measurement of serum from pregnant donors using the GMR assays was highly concordant with those obtained using a clinical mass spectrometry (MS)-based assay for the same protein markers. The MS assay requires capitally intense equipment and highly trained operators with a few days turnaround time, whereas the GMR assays can be performed in minutes on small, inexpensive instruments with minimal personnel training and microfluidic automation. The potential for high sensitivity, accuracy, and speed of the GMR assays, along with low equipment and personnel requirements, make them good candidates for developing point-of-care tests. Rapid turnaround risk assessment for preterm birth would enable patient testing and counseling at the same clinic visit, thereby increasing the timeliness of recommended interventions.

Early gut microbiota intervention in premature infants: Application perspectives

BACKGROUND

Preterm birth is the leading cause of death in children under the age of five. One of the major factors contributing to the high risk of diseases and deaths in premature infants is the incomplete development of the intestinal immune system. The gut microbiota has been widely recognized as a critical factor in promoting the development and function of the intestinal immune system after birth. However, the gut microbiota of premature infants is at high risk of dysbiosis, which is highly associated with adverse effects on the development and education of the early life immune system. Early intervention can modulate the colonization and development of gut microbiota and has a long-term influence on the development of the intestinal immune system.

AIM OF REVIEW

This review aims to summarize the characterization, interconnection, and underlying mechanism of gut microbiota and intestinal innate immunity in premature infants, and to discuss the status, applicability, safety, and prospects of different intervention strategies in premature infants, thus providing an overview and outlook of the current applications and remaining gaps of early intervention strategies in premature infants.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review is focused on three key concepts. Firstly, the gut microbiota of premature infants is at high risk of dysbiosis, resulting in dysfunctional intestinal immune system processes. Secondly, contributing roles of early intervention have been observed in improving the intestinal environment and promoting gut microbiota colonization, which is significant in the development and function of gut immunity in premature infants. Thirdly, different strategies of early intervention, such as probiotics, fecal microbiota transplantation, and nutrients, show different safety, applicability, and outcome in premature infants, and the underlying mechanism is complex and poorly understood.

Human breast milk: A promising treatment for necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a severe gastrointestinal disorder occurring in newborns, with a mortality rate ranging from 20 % to 30 %. The existing therapeutic approaches for NEC are limited in their effectiveness. Various factors contribute to the development of NEC, including disruption of barrier function, dysregulation of the intestinal immune system, and abnormal colonization of the intestinal microbiota. Researchers have shown considerable interest in exploring the therapeutic potential of the constituents present in human breast milk (HBM) for treating NEC. HBM contains numerous bioactive components, such as exosomes, growth factors, and oligosaccharides. However, the precise mechanisms by which HBM exerts its protective effects against NEC remain incompletely understood. In this study, our objective was to comprehensively review the bioactive substances present in HBM, aiming to facilitate the development of novel therapeutic strategies for NEC.

Clinical Studies on the Supplementation of Manufactured Human Milk Oligosaccharides: A Systematic Review

Human milk oligosaccharides (HMOs) are a major component of human milk. They are associated with multiple health benefits and are manufactured on a large scale for their addition to different food products. In this systematic review, we evaluate the health outcomes of published clinical trials involving the supplementation of manufactured HMOs. We screened the PubMed database and Cochrane Library, identifying 26 relevant clinical trials and five publications describing follow-up studies. The clinical trials varied in study populations, including healthy term infants, infants with medical indications, children, and adults. They tested eight different HMO structures individually or as blends in varying doses. All trials included safety and tolerance assessments, and some also assessed growth, stool characteristics, infections, gut microbiome composition, microbial metabolites, and biomarkers. The studies consistently found that HMO supplementation was safe and well tolerated. Infant studies reported a shift in outcomes towards those observed in breastfed infants, including stool characteristics, gut microbiome composition, and intestinal immune markers. Beneficial gut health and immune system effects have also been observed in other populations following HMO supplementation. Further clinical trials are needed to substantiate the effects of HMO supplementation on human health and to understand their structure and dose dependency.

Fecal pH and redox as functional markers in the premature infant gut microbiome

The infant gut microbiome is a crucial factor in health and development. In preterm infants, altered gut microbiome composition and function have been linked to serious neonatal complications such as necrotizing enterocolitis and sepsis, which can lead to long-term disability. Although many studies have described links between microbiome composition and disease risk, there is a need for biomarkers to identify infants at risk of these complications in practice. In this study, we obtained stool samples from preterm infant participants longitudinally during the first postnatal months, and measured pH and redox, as well as SCFA content and microbiome composition by 16S rRNA gene amplicon sequencing. These outcomes were compared to clinical data to better understand the role of pH and redox in infant gut microbiome development and overall health, and to assess the potential utility of pH and redox as biomarkers. We found that infants born earlier or exposed to antibiotics exhibited increased fecal pH, and that redox potential increased with postnatal age. These differences may be linked to changes in SCFA content, which was correlated with pH and increased with age. Microbiome composition was also related to birth weight, age, pH, and redox. Our findings suggest that pH and redox may serve as biomarkers of metabolic state in the preterm infant gut.

A bacterial sialidase mediates early life colonization by a pioneering gut commensal

The early microbial colonization of the gastrointestinal tract can lead to long-term impacts in development and overall human health. Keystone species, including Bacteroides spp ., play a crucial role in maintaining the structure, diversity, and function of the intestinal ecosystem. However, the process by which a defined and resilient community is curated and maintained during early life remains inadequately understood. Here, we show that a single sialidase, NanH, in Bacteroides fragilis mediates stable occupancy of the intestinal mucosa and regulates the commensal colonization program during the first weeks of life. This program is triggered by sialylated glycans, including those found in human milk oligosaccharides and intestinal mucus. After examining the dynamics between pioneer gut Bacteroides species in the murine gut, we discovered that NanH enables vertical transmission from dams to pups and promotes B. fragilis dominance during early life. Furthermore, we demonstrate that NanH facilitates commensal resilience and recovery after antibiotic treatment in a defined microbial community. Collectively, our study reveals a co-evolutionary mechanism between the host and the microbiota mediated through host-derived glycans to promote stable intestinal colonization.

Diet-microbe-host interaction in early life

Breast milk bioactives are important for infant microbiome and immunity.

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.

Prebiotics to prevent necrotising enterocolitis in very preterm or very low birth weight infants

BACKGROUND

Dietary supplementation with prebiotic oligosaccharides to modulate the intestinal microbiome has been proposed as a strategy to reduce the risk of necrotising enterocolitis (NEC) and associated mortality and morbidity in very preterm or very low birth weight (VLBW) infants.

OBJECTIVES

To assess the benefits and harms of enteral supplementation with prebiotics (versus placebo or no treatment) for preventing NEC and associated morbidity and mortality in very preterm or VLBW infants.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, the Maternity and Infant Care database and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), from the earliest records to July 2022. We searched clinical trials databases and conference proceedings, and examined the reference lists of retrieved articles.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs comparing prebiotics with placebo or no prebiotics in very preterm (< 32 weeks' gestation) or VLBW (< 1500 g) infants. The primary outcomes were NEC and all-cause mortality, and the secondary outcomes were late-onset invasive infection, duration of hospitalisation since birth, and neurodevelopmental impairment.

DATA COLLECTION AND ANALYSIS

Two review authors separately evaluated risk of bias of the trials, extracted data, and synthesised effect estimates using risk ratio (RR), risk difference (RD), and mean difference (MD), with associated 95% confidence intervals (CIs). The primary outcomes of interest were NEC and all-cause mortality; our secondary outcome measures were late-onset (> 48 hours after birth) invasive infection, duration of hospitalisation, and neurodevelopmental impairment. We used the GRADE approach to assess the level of certainty of the evidence.

MAIN RESULTS

We included seven trials in which a total of 705 infants participated. All the trials were small (mean sample size 100). Lack of clarity on methods to conceal allocation and mask caregivers or investigators were potential sources of bias in three of the trials. The studied prebiotics were fructo- and galacto-oligosaccharides, inulin, and lactulose, typically administered daily with enteral feeds during birth hospitalisation. Meta-analyses of data from seven trials (686 infants) suggest that prebiotics may result in little or no difference in NEC (RR 0.97, 95% CI 0.60 to 1.56; RD none fewer per 1000, 95% CI 50 fewer to 40 more; low-certainty evidence), all-cause mortality (RR 0.43, 95% CI 0.20 to 0.92; 40 per 1000 fewer, 95% CI 70 fewer to none fewer; low-certainty evidence), or late-onset invasive infection (RR 0.79, 95% CI 0.60 to 1.06; 50 per 1000 fewer, 95% CI 100 fewer to 10 more; low-certainty evidence) prior to hospital discharge. The certainty of this evidence is low because of concerns about the risk of bias in some trials and the imprecision of the effect size estimates. The data available from one trial provided only very low-certainty evidence about the effect of prebiotics on measures of neurodevelopmental impairment (Bayley Scales of Infant Development (BSID) Mental Development Index score < 85: RR 0.84, 95% CI 0.25 to 2.90; very low-certainty evidence; BSID Psychomotor Development Index score < 85: RR 0.24, 95% 0.03 to 2.00; very low-certainty evidence; cerebral palsy: RR 0.35, 95% CI 0.01 to 8.35; very low-certainty evidence).

AUTHORS' CONCLUSIONS

The available trial data provide low-certainty evidence about the effects of prebiotics on the risk of NEC, all-cause mortality before discharge, and invasive infection, and very low-certainty evidence about the effect on neurodevelopmental impairment for very preterm or VLBW infants. Our confidence in the effect estimates is limited; the true effects may be substantially different. Large, high-quality trials are needed to provide evidence of sufficient validity to inform policy and practice decisions.

Probiotics and Human Milk Differentially Influence the Gut Microbiome and NEC Incidence in Preterm Pigs

Necrotizing enterocolitis (NEC) is the leading cause of death caused by gastrointestinal disease in preterm infants. Major risk factors include prematurity, formula feeding, and gut microbial colonization. Microbes have been linked to NEC, yet there is no evidence of causal species, and select probiotics have been shown to reduce NEC incidence in infants. In this study, we evaluated the effect of the probiotic Bifidobacterium longum subsp. infantis (BL. infantis), alone and in combination with a human milk oligosaccharide (HMO)-sialylactose (3'SL)-on the microbiome, and the incidence of NEC in preterm piglets fed an infant formula diet. We studied 50 preterm piglets randomized between 5 treatments: (1) Preterm infant formula, (2) Donor human milk (DHM), (3) Infant formula + 3'SL, (4) Infant formula + BL. infantis, and (5) Infant formula and BL. infantis + 3'SL. NEC incidence and severity were assessed through the evaluation of tissue from all the segments of the GI tract. The gut microbiota composition was assessed both daily and terminally through 16S and whole-genome sequencing (WGS) of rectal stool samples and intestinal contents. Dietary BL. infantis and 3'SL supplementation had no effect, yet DHM significantly reduced the incidence of NEC. The abundance of BL. infantis in the gut contents negatively correlated with disease severity. Clostridium sensu stricto 1 and Clostridium perfringens were significantly more abundant in NEC and positively correlated with disease severity. Our results suggest that pre- and probiotics are not sufficient for protection from NEC in an exclusively formula-based diet. The results highlight the differences in microbial species positively associated with both diet and NEC incidence.

Human Milk Oligosaccharide Profile across Lactation Stages in Israeli Women-A Prospective Observational Study

Human milk oligosaccharides (HMOs) stimulate the growth of gut commensals, prevent the adhesion of enteropathogens and modulate host immunity. The major factors influencing variations in the HMO profile are polymorphisms in the secretor (Se) or Lewis (Le) gene, which affect the activity of the enzymes fucoslytransferase 2 and 3 (FUT2 and FUT3) that lead to the formation of four major fucosylated and non-fucosylated oligosaccharides (OS). This pilot study aimed to determine the HMO profile of Israeli breastfeeding mothers of 16 term and 4 preterm infants, from a single tertiary center in the Tel Aviv area. Fifty-two human milk samples were collected from 20 mothers at three-time points: colostrum, transitional milk and mature milk. The concentrations of nine HMOs were assessed using liquid chromatography coupled with mass spectra chromatograms. Fifty-five percent of the mothers were secretors and 45% were non-secretors. Infant sex affected HMO levels depending on the maternal secretor status. Secretor mothers to boys had higher levels of FUT2-dependent OS and higher levels of disialyllacto-N-tetraose in the milk of mothers to girls, whereas non-secretor mothers to girls had higher levels of 3'-sialyllactose. In addition, the season at which the human milk samples were obtained affected the levels of some HMOs, resulting in significantly lower levels in the summer. Our findings provide novel information on the irregularity in the HMO profile among Israeli lactating women and identify several factors contributing to this variability.

Necrotizing enterocolitis: recent advances in treatment with translational potential

Necrotizing enterocolitis (NEC) is one of the most prevalent and devastating gastrointestinal disorders in neonates. Despite advances in neonatal care, the incidence and mortality due to NEC remain high, highlighting the need to devise novel treatments for this disease. There have been a number of recent advancements in therapeutic approaches for the treatment of NEC; these involve remote ischemic conditioning (RIC), stem cell therapy, breast milk components (human milk oligosaccharides, exosomes, lactoferrin), fecal microbiota transplantation, and immunotherapy. This review summarizes the most recent advances in NEC treatment currently underway as well as their applicability and associated challenges and limitations, with the aim to provide new insight into the paradigm of care for NEC worldwide.

Paneth cell development in the neonatal gut: pathway regulation, development, and relevance to necrotizing enterocolitis

Paneth cells (PCs) are intestinal epithelial cells (IECs) that contain eosinophilic granules, which are located in Lieberkühn crypts. An increasing number of animal and human experiments have indicated that PCs are involved in the progression of a variety of intestinal as well as systemic inflammatory responses including necrotizing enterocolitis (NEC). NEC is an enteric acquired disease with high mortality that usually occurs in premature infants and neonates, however the underlying mechanisms remain unclear. In this review, we summarize the features of PCs, including their immune function, association with gut microbiota and intestinal stem cells, and their mechanism of regulating IEC death to explore the possible mechanisms by which PCs affect NEC.

2022 Fleming Prize Lecture: diet-microbe-host interaction in early life

The last decade has witnessed a meteoric rise in research focused on characterizing the human microbiome and identifying associations with disease risk. The advent of sequencing technology has all but eradicated gel-based fingerprinting approaches for studying microbial ecology, while at the same time traditional microbiological culture is undergoing a renaissance. Although multiplexed high-throughput sequencing is relatively new, the discoveries leading to this are nearly 50 years old, coinciding with the inaugural Microbiology Society Fleming Prize lecture. It was an honour to give the 2022 Fleming Prize lecture and this review will cover the topics from that lecture. The focus will be on the bacterial community in early life, beginning with term infants before moving on to infants delivered prematurely. The review will discuss recent work showing how human milk oligosaccharides (HMOs), an abundant but non-nutritious component of breast milk, can modulate infant microbiome and promote the growth of Bifidobacterium spp. This has important connotations for preterm infants at risk of necrotizing enterocolitis, a devastating intestinal disease representing the leading cause of death and long-term morbidity in this population. With appropriate mechanistic studies, it may be possible to harness the power of breast milk bioactive factors and infant gut microbiome to improve short- and long-term health in infants.

Goat milk powder supplemented with branched-chain fatty acid: influence on quality and microstructure

BACKGROUND

Branched-chain fatty acid (BCFA) is effective in preventing and helping to treat neonatal necrotizing enterocolitis. It is essential to supplement goat-milk powder for formula-fed preterm infants with BCFA. In this study, the quality and microstructures of milk powders supplemented with different concentrations of BCFA were evaluated, using goat milk powder without BCFA as the control group (CG).

RESULTS

In comparison with the CG, goat milk powder supplemented with BCFA exhibited smaller fat globules and a significant drop in overall particle size. During 16 weeks of storage, BCFA-supplemented groups showed suitable moisture content and viscosity and good solubility. The BCFA also helped reduce the number of folds on the surface of the milk powder particles.

CONCLUSION

The findings of this study indicate that goat milk powders with BCFA exhibit differences in quality and microstructure in comparison with ordinary goat milk powder, which is relevant for the future development and application of BCFA in foods. © 2022 Society of Chemical Industry.

Human Milk Oligosaccharides Variation in Gestational Diabetes Mellitus Mothers

Gestational diabetes mellitus (GDM) is a common disease of pregnancy, but with very limited knowledge of its impact on human milk oligosaccharides (HMOs) in breast milk. This study aimed to explore the lactational changes in the concentration of HMOs in exclusively breastfeeding GDM mothers and the differences between GDM and healthy mothers. A total of 22 mothers (11 GDM mothers vs. 11 healthy mothers) and their offspring were enrolled in the study and the levels of 14 HMOs were measured in colostrum, transitional milk, and mature milk. Most of the HMOs showed a significant temporal trend with decreasing levels over lactation; however, there were some exceptions for 2′-Fucosyllactose (2′-FL), 3-Fucosyllactose (3-FL), Lacto-N-fucopentaose II (LNFP-II), and Lacto-N-fucopentaose III (LNFP-III). Lacto-N-neotetraose (LNnT) was significantly higher in GDM mothers in all time points and its concentrations in colostrum and transitional milk were correlated positively with the infant’s weight-for-age Z-score at six months postnatal in the GDM group. Significant group differences were also found in LNFP-II, 3′-Sialyllactose (3′-SL), and Disialyllacto-N-tetraose (DSLNT) but not in all lactational periods. The role of differently expressed HMOs in GDM needs to be further explored by follow-up studies.