Establishment of the early-life microbiome: a DOHaD perspective

Food Insecurity Is Associated with Diet Quality in Pregnancy: A Cross-Sectional Study

Household food insecurity (HFI) and poorer prenatal diet quality are both associated with adverse perinatal outcomes. However, research assessing the relationship between HFI and diet quality in pregnancy is limited. A cross-sectional online survey was conducted to examine the relationship between HFI and diet quality among 1540 pregnant women in Australia. Multiple linear regression models were used to examine the associations between HFI severity (marginal, low, and very low food security compared to high food security) and diet quality and variety, adjusting for age, education, equivalised household income, and relationship status. Logistic regression models were used to assess the associations between HFI and the odds of meeting fruit and vegetable recommendations, adjusting for education. Marginal, low, and very low food security were associated with poorer prenatal diet quality (adj β = -1.9, -3.6, and -5.3, respectively; p < 0.05), and very low food security was associated with a lower dietary variety (adj β = -0.5, p < 0.001). An association was also observed between HFI and lower odds of meeting fruit (adjusted odds ratio [AOR]: 0.61, 95% CI: 0.49-0.76, p < 0.001) and vegetable (AOR: 0.40, 95% CI: 0.19-0.84, p = 0.016) recommendations. Future research should seek to understand what policy and service system changes are required to reduce diet-related disparities in pregnancy.

A Murine Model of Maternal Micronutrient Deficiencies and Gut Inflammatory Host-microbe Interactions in the Offspring

BACKGROUND & AIMS

Micronutrient deficiency (MND) (ie, lack of vitamins and minerals) during pregnancy is a major public health concern. Historically, studies have considered micronutrients in isolation; however, MNDs rarely occur alone. The impact of co-occurring MNDs on public health, mainly in shaping mucosal colonization by pathobionts from the Enterobacteriaceae family, remains undetermined due to lack of relevant animal models.

METHODS

To establish a maternal murine model of multiple MND (MMND), we customized a diet deficient in vitamins (A, B12, and B9) and minerals (iron and zinc) that most commonly affect children and women of reproductive age. Thereafter, mucosal adherence by Enterobacteriaceae, the associated inflammatory markers, and proteomic profile of intestines were determined in the offspring of MMND mothers (hereafter, low micronutrient [LM] pups) via bacterial plating, flow cytometry, and mass spectrometry, respectively. For human validation, Enterobacteriaceae abundance, assessed via 16s sequencing of 3-month-old infant fecal samples (n = 100), was correlated with micronutrient metabolites using Spearman's correlation in meconium of children from the CHILD birth cohort.

RESULTS

We developed an MMND model and reported an increase in colonic abundance of Enterobacteriaceae in LM pups at weaning. Findings from CHILD cohort confirmed a negative correlation between Enterobacteriaceae and micronutrient availability. Furthermore, pro-inflammatory cytokines and increased infiltration of lymphocyte antigen 6 complex high monocytes and M1-like macrophages were evident in the colons of LM pups. Mechanistically, mitochondrial dysfunction marked by reduced expression of nicotinamide adenine dinucleotide (NAD)H dehydrogenase and increased expression of NAD phosphate oxidase (Nox) 1 contributed to the Enterobacteriaceae bloom.

CONCLUSION

This study establishes an early life MMND link to intestinal pathobiont colonization and mucosal inflammation via damaged mitochondria in the offspring.

Necrotizing Enterocolitis and the Preterm Infant Microbiome

Preterm infants differ significantly from their term infant counterparts regarding bacterial colonization patterns related to maternal microbiota diversity, mode of delivery, feeding type, antibiotic exposure, and the environmental influences related to prolonged hospitalization in the neonatal intensive care unit (NICU). Necrotizing enterocolitis (NEC), a multifactorial intestinal disorder characterized by ischemic bowel disease, disproportionately impacts preterm infants and has a high disease burden. Recent studies in the basic, translational, and clinical scientific literature have advanced knowledge into this complex disease process. Despite the explosion of research into NEC, however, there is a still a great deal unknown about this devastating illness. Additionally, the disease morbidity and mortality for NEC remain high despite advances in therapy options. This chapter reviews the current literature into the preterm infant microbiome, pathogenesis of NEC, potential targets for altering preterm microbiome, influence of microbiome on other organ systems, long-term implications of microbiome dysbiosis, and future directions of study.

Early life programming by diet can play a role in risk reduction of otitis in dogs

Introduction

Otitis in dogs is often chronic while local treatment primarily consists of flushing, antibiotics, and/or antifungals. We were interested in finding early life variables that associate with otitis later in life, preferably some that could be modified.

Methods

A cross-sectional hypothesis-driven study with longitudinal data was performed to search for associations between pre- and postnatal exposures, and the incidence of owner-reported otitis in dogs at over 1 year of age. The multivariate logistic regression analysis study included data from 3,064 dogs and explored 26 different early life variables at four early life stages: prenatal, neonatal, postnatal, and puppyhood. We compared two feeding patterns, a non-processed meat-based diet (NPMD, raw) and an ultra-processed carbohydrate-based diet (UPCD, dry).

Results

We report that eating a NPMD diet significantly decreased the risk of otitis later in life, while eating a UPCD diet significantly increased the risk. This was seen in different life stages of mother or puppy: The maternal diet during pregnancy (p=0.011) and the puppies' diet from 2 to 6 months of age (p=0.019) were both significantly associated with otitis incidence later in life, whereas the puppies' first solid diet, was associated in the same way, but did not reach significance (p=0.072). Also, analyzing food ratios showed that when puppies were consuming >25% of their food as NPMD it significantly decreased their incidence of otitis later in life, while a ratio of >75% UPCD in their diet significantly increased their risk of otitis. Also, if the dog was born in the current family, was exposed to sunlight for more than 1 hour daily, and was raised on a dirt floor during puppyhood, there was a lower risk of otitis development later in life.

Discussion

The findings only suggest causality, and further studies are required. However, we propose that veterinarians, breeders, and owners can impact otitis risk by modifying factors such as diet and environment.

Investigation and analysis of children's behavior and outpatient number of respiratory diseases in Shanghai before and after the COVID-19 pandemic

Objective

Alterations in behavioral habits of children were analyzed in Shanghai in the winters prior to and following the COVID-19 pandemic, with the aim of assisting in the prevention of children's respiratory diseases in the post-pandemic era.

Method

This cross-sectional survey was conducted via an offline questionnaire from January 1 to February 28, 2021. The behavioral habits of Shanghainese children in different age groups during the winter of 2019 and 2020 were statistically analyzed using the SPSS 25.0 software. The parameters surveyed and analyzed included the frequency of outdoor activities, self-protection measures (frequency of wearing masks and washing hands after going out), travel history, time to visit since symptom onset, and influenza vaccination status. Lastly, the number of cases of respiratory diseases in the pediatric outpatient department of our hospital was analyzed during the same period.

Result

A total of 1816 questionnaires were investigated and analyzed, and the results revealed that self-protection measures were significantly enhanced in children of all age groups after the COVID-19 pandemic breakout compared with those before the pandemic, whereas the frequency of outdoor activities and traveling were reduced. In the age group over 3 years old, the time to visit since symptom onset was shorter, and the influenza vaccination rate increased following the pandemic. During the same period, the number of cases of children with respiratory diseases in our outpatient department was significantly decreased compared with that prior to the COVID-19 pandemic.

Conclusion

The COVID-19 pandemic has had a significant impact on self-protection measures, outdoor activities, and other children's behaviors in all age groups in Shanghai. These changes in habits were correlated with a lower incidence and transmission of respiratory diseases in children. Overall, this study lays a theoretical basis for the prevention of childhood illnesses in the post-pandemic era.

Interactions with alloparents are associated with the diversity of infant skin and fecal bacterial communities in Chicago, United States

INTRODUCTION

Social interactions shape the infant microbiome by providing opportunities for caregivers to spread bacteria through physical contact. With most research focused on the impact of maternal-infant contact on the infant gut microbiome, it is unclear how alloparents (i.e., caregivers other than the parents) influence the bacterial communities of infant body sites that are frequently contacted during bouts of caregiving, including the skin.

METHODS

To begin to understand how allocare may influence the diversity of the infant microbiome, detailed questionnaire data on infant-alloparent relationships and specific allocare behaviors were coupled with skin and fecal microbiome samples (four body sites) from 48 infants living in Chicago, United States.

RESULTS

Data from 16S rRNA gene amplicon sequencing indicated that infant skin and fecal bacterial diversity showed strong associations (positive and negative) to having female adult alloparents. Alloparental feeding and co-sleeping displayed stronger associations to infant bacterial diversity compared to playing or holding. The associations with allocare behaviors differed in magnitude and direction across infant body sites. Bacterial relative abundances varied by infant-alloparent relationship and breastfeeding status.

CONCLUSION

This study provides some of the first evidence of an association between allocare and infant skin and fecal bacterial diversity. The results suggest that infants' exposure to bacteria from the social environment may vary based on infant-alloparent relationships and allocare behaviors. Since the microbiome influences immune system development, variation in allocare that impacts the diversity of infant bacterial communities may be an underexplored dimension of the social determinants of health in early life.

Breastfeeding patterns are associated with human milk microbiome composition: The Mother-Infant Microbiomes, Behavior, and Ecology Study (MIMBES)

The human milk microbiome (HMM) is hypothesized to be seeded by multiple factors, including the infant oral microbiome during breastfeeding. However, it is not known whether breastfeeding patterns (e.g., frequency or total time) impact the composition of the HMM. As part of the Mother-Infant Microbiomes, Behavior, and Ecology Study (MIMBES), we analyzed data from naturalistic observations of 46 mother-infant dyads living in the US Pacific Northwest and analyzed milk produced by the mothers for its bacterial diversity and composition. DNA was extracted from milk and the V1-V3 region of the 16S rRNA gene was amplified and sequenced. We hypothesized that number of breastfeeding bouts (breastfeeding sessions separated by >30 seconds) and total time breastfeeding would be associated with HMM α-diversity (richness, diversity, or evenness) and differential abundance of HMM bacterial genera. Multiple linear regression was used to examine associations between HMM α-diversity and the number of breastfeeding bouts or total time breastfeeding and selected covariates (infant age, maternal work outside the home, frequency of allomother physical contact with the infant, non-household caregiving network). HMM richness was inversely associated with number of breastfeeding bouts and frequency of allomother physical contact, but not total time breastfeeding. Infants' non-household caregiving network was positively associated with HMM evenness. In two ANCOM-BC analyses, abundances of 5 of the 35 most abundant genera were differentially associated with frequency of breastfeeding bouts (Bifidobacterium, Micrococcus, Pedobacter, Acidocella, Achromobacter); 5 genera (Bifidobacterium, Agreia, Pedobacter, Rugamonas, Stenotrophomonas) were associated with total time breastfeeding. These results indicate that breastfeeding patterns and infant caregiving ecology may play a role in influencing HMM composition. Future research is needed to identify whether these relationships are consistent in other populations and if they are associated with variation in the infant's gastrointestinal (including oral) microbiome.

Human microbiome variation associated with race and ethnicity emerges as early as 3 months of age

Human microbiome variation is linked to the incidence, prevalence, and mortality of many diseases and associates with race and ethnicity in the United States. However, the age at which microbiome variability emerges between these groups remains a central gap in knowledge. Here, we identify that gut microbiome variation associated with race and ethnicity arises after 3 months of age and persists through childhood. One-third of the bacterial taxa that vary across caregiver-identified racial categories in children are taxa reported to also vary between adults. Machine learning modeling of childhood microbiomes from 8 cohort studies (2,756 samples from 729 children) distinguishes racial and ethnic categories with 87% accuracy. Importantly, predictive genera are also among the top 30 most important taxa when childhood microbiomes are used to predict adult self-identified race and ethnicity. Our results highlight a critical developmental window at or shortly after 3 months of age when social and environmental factors drive race and ethnicity-associated microbiome variation and may contribute to adult health and health disparities.

Identifying Microbiome Dynamics in Pediatric IBD: More than a Family Matter

BACKGROUND

Pediatric inflammatory bowel disease (IBD) is a chronic inflammatory intestinal disease that affects both children and adolescents. Symptoms can significantly affect a child's growth, development, and quality of life, making early diagnosis and effective management crucial. This study focuses on treatment-naïve pediatric IBD patients and their immediate families to identify the role of the microbiome in disease onset.

METHODS

Nine families with pediatric IBD were recruited, comprising seven drug-naïve Crohn's disease (CD) patients and two drug-naïve ulcerative colitis (UC) patients, as well as twenty-four healthy siblings/parents. Fecal samples were collected for 16S ribosomal RNA gene sequencing and bioinformatics analysis.

RESULTS

We identified patterns of dysbiosis and hallmark microbial taxa among patients who shared ethnic, habitual, and dietary traits with themselves and their families. In addition, we examined the impact of the disease on specific microbial taxa and how these could serve as potential biomarkers for early detection.

CONCLUSIONS

Our results suggest a potential role of maternal factors in the establishment and modulation of the early life microbiome, consistent with the current literature, which may have implications for understanding the etiology and progression of IBD.

Microbiome-Gut-Mucosal-Immune-Brain Axis and Autism Spectrum Disorder (ASD): A Novel Proposal of the Role of the Gut Microbiome in ASD Aetiology

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterised by deficits in social interaction and communication, as well as restricted and stereotyped interests. Due of the high prevalence of gastrointestinal disorders in individuals with ASD, researchers have investigated the gut microbiota as a potential contributor to its aetiology. The relationship between the microbiome, gut, and brain (microbiome-gut-brain axis) has been acknowledged as a key factor in modulating brain function and social behaviour, but its connection to the aetiology of ASD is not well understood. Recently, there has been increasing attention on the relationship between the immune system, gastrointestinal disorders and neurological issues in ASD, particularly in relation to the loss of specific species or a decrease in microbial diversity. It focuses on how gut microbiota dysbiosis can affect gut permeability, immune function and microbiota metabolites in ASD. However, a very complete study suggests that dysbiosis is a consequence of the disease and that it has practically no effect on autistic manifestations. This is a review of the relationship between the immune system, microbial diversity and the microbiome-gut-brain axis in the development of autistic symptoms severity and a proposal of a novel role of gut microbiome in ASD, where dysbiosis is a consequence of ASD-related behaviour and where dysbiosis in turn accentuates the autistic manifestations of the patients via the microbiome-gut-brain axis in a feedback circuit.

Whole-body microbiota of newborn calves and their response to prenatal vitamin and mineral supplementation

Early life microbial colonization and factors affecting colonization patterns are gaining interest due to recent developments suggesting that early life microbiome may play a role in Developmental Origins of Health and Disease. In cattle, limited information exists on the early microbial colonization of anatomical sites involved in bovine health beyond the gastrointestinal tract. Here, we investigated 1) the initial microbial colonization of seven different anatomical locations in newborn calves and 2) whether these early life microbial communities and 3) serum cytokine profiles are influenced by prenatal vitamin and mineral (VTM) supplementation. Samples were collected from the hoof, liver, lung, nasal cavity, eye, rumen (tissue and fluid), and vagina of beef calves that were born from dams that either received or did not receive VTM supplementation throughout gestation (n = 7/group). Calves were separated from dams immediately after birth and fed commercial colostrum and milk replacer until euthanasia at 30 h post-initial colostrum feeding. The microbiota of all samples was assessed using 16S rRNA gene sequencing and qPCR. Calf serum was subjected to multiplex quantification of 15 bovine cytokines and chemokines. Our results indicated that the hoof, eye, liver, lung, nasal cavity, and vagina of newborn calves were colonized by site-specific microbiota, whose community structure differed from the ruminal-associated communities (0.64 ≥ R² ≥ 0.12, p ≤ 0.003). The ruminal fluid microbial community was the only one that differed by treatment (p < 0.01). However, differences (p < 0.05) by treatment were detected in microbial richness (vagina); diversity (ruminal tissue, fluid, and eye); composition at the phylum and genus level (ruminal tissue, fluid, and vagina); and in total bacterial abundance (eye and vagina). From serum cytokines evaluated, concentration of chemokine IP-10 was greater (p = 0.02) in VTM calves compared to control calves. Overall, our results suggest that upon birth, the whole-body of newborn calves are colonized by relatively rich, diverse, and site-specific bacterial communities. Noticeable differences were observed in ruminal, vaginal, and ocular microbiota of newborn calves in response to prenatal VTM supplementation. These findings can derive future hypotheses regarding the initial microbial colonization of different body sites, and on maternal micronutrient consumption as a factor that may influence early life microbial colonization.

Profile of the intestinal microbiota of patients with cystic fibrosis: A systematic review

BACKGROUND & AIMS

Cystic fibrosis (CF) is a multisystem disease that can compromise several human body organs. The autosomal recessive genetic disorder is caused by different mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, responsible for chloride ion transport across apical membranes of epithelial cells in tissues and bicarbonate secretion. In this study, we provide a systematic review of the profile of the intestinal microbiota of cystic fibrosis individuals.

METHODS

The review was conducted according to Preferred Items of Reports for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed/MEDLINE and Scopus databases were searched for relevant articles until Jully 2022.

RESULTS

Eighteen studies (1304 participants) met the inclusion criteria. The quality and bias was assessed using the Methodological index for non-randomized studies (MINORS) tool, with the majority of the studies indicating medium to high quality. Results showed significant changes in the composition of the intestinal microbiota of the individuals with CF compared with healthy controls, with increased of Enterococcus, Veillonella, and Streptococcus, and decreased of Bifidobacterium, Roseburia, and Alistipes genus. The intestinal bacterial community of CF patients was marked by a reduction in its richness and diversity.

CONCLUSION

The systematic review suggests a change in the intestinal microbiota of CF individuals, characterized by a reduction in microbial diversity and abundance of some bacterial markers.

Delayed Microbial Maturation Durably Exacerbates Th17-driven Asthma in Mice

Microbial maturation disrupted by early-life dysbiosis has been linked with increased asthma risk and severity; however, the immunological mechanisms underpinning this connection are poorly understood. We sought to understand how delaying microbial maturation drives worsened asthma outcomes later in life and its long-term durability. Drinking water was supplemented with antibiotics on Postnatal Days 10-20. To assess the immediate and long-term effects of delaying microbial maturation on experimental asthma, we initiated house dust mite exposure when bacterial diversity was either at a minimum or had recovered. Airway hyperresponsiveness, histology, pulmonary leukocyte recruitment, flow cytometric analysis of cytokine-producing lymphocytes, and assessment of serum IgG1 (Immunoglobulin G1) and IgE (Immunoglobulin E) concentrations were performed. RT-PCR was used to measure IL-13 (Interleukin 13)-induced gene expression in sequentially sorted mesenchymal, epithelial, endothelial, and leukocyte cell populations from the lung. Delayed microbial maturation increased allergen-driven airway hyperresponsiveness and Th17 frequency compared with allergen-exposed control mice, even when allergen exposure began after bacterial diversity recovered. Blockade of IL-17A (Interleukin 17A) reversed the airway hyperresponsiveness phenotype. In addition, allergen exposure in animals that experienced delayed microbial maturation showed signs of synergistic signaling between IL-13 and IL-17A in the pulmonary mesenchymal compartment. Delaying microbial maturation in neonates promotes the development of more severe asthma by increasing Th17 frequency, even if allergen exposure is initiated weeks after microbial diversity is normalized. In addition, IL-17A-aggravated asthma is associated with increased expression of IL-13-induced genes in mesenchymal, but not epithelial cells.

Rural Embodiment and Community Health: an Anthropological Case Study on Biocultural Determinants of Tropical Disease Infection and Immune System Development in the USA

Purpose of Review

Biocultural methods are critically important for identifying environmental and socioeconomic factors linked with tropical disease risk and outcomes. For example, embodiment theory refers to the process by which lived experiences impact individual biology. Increased exposure to pathogens, chronic psychosocial stress, and unequal resource access are all outcomes linked with discrimination and poverty. Through lived experiences, race and socioeconomic inequality can literally become embodied-get under the skin and affect physiology-impacting immune responses and contributing to lifelong health disparities. Yet, few studies have investigated tropical disease patterns and associated immune function using embodiment theory to understand lasting physiological impacts associated with living in a high-pathogen environment.

Recent Findings

Here, we use preliminary data drawn from the Rural Embodiment and Community Health (REACH) study to assess whether pathogen exposure and immune stimulation within a sample of children from the Mississippi Delta are associated with household income. We also test whether immune marker levels-assessed with enzyme-linked immunosorbent assays using dried blood spot samples-vary between the REACH sample and a similarly aged nationally representative NHANES sample. Immune marker levels did not differ significantly between REACH participants living below vs. above the federal poverty line, yet immunoglobulin E levels-a marker of macroparasite infection-were higher among REACH study participants compared to the NHANES sample.

Summary

These results may suggest community-level pathogenic exposures (i.e., parasitic infections) are embodied by REACH participants with implications for long-term immune function, potentially resulting in immune aspects that differ from nationally representative samples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40475-023-00282-z.

Lactobacillus reuteri improves the development and maturation of fecal microbiota in piglets through mother-to-infant microbe and metabolite vertical transmission

BACKGROUND

The immature neonatal fecal microbiota substantially impacts the development of gut health and greatly increases the risk of disease. Developing effective strategies to modulate the development of neonatal fecal microbiota has great significance. Herein, we investigated whether the maternal dietary supplementation and oral administration of Lactobacillus reuteri could effectively promote the development and maturation of the fecal microbiome in piglets from birth to weaning.

RESULTS

Metagenomic analysis of colostrum showed that maternal dietary L. reuteri supplementation influenced the overall microbiota composition, decreased the abundance of the phylum Proteobacteria and increased that of the species Bifidobacterium choerinum. KEGG pathway analysis revealed that maternal L. reuteri supplementation enriched the lysine biosynthesis and glycolysis/gluconeogenesis pathways and downregulated the bacterial invasion of epithelial cells in the colostrum. In addition, L. reuteri supplementation significantly altered the metabolite features and modules in umbilical cord blood serum based on metabolomics. Further, a significant covariation was observed between these differential metabolites and the species in colostrum. Maternal dietary L. reuteri supplementation also significantly influenced the microbiota composition and increased the meconium abundance of beneficial bacteria (such as Romboutsia, Lactobacillus, Blautia, Butyricicoccus, and Ruminococcus), some of which were markedly associated with several differential metabolites in umbilical cord blood serum between two groups. Notably, both the maternal dietary supplementation and oral intake of L. reuteri had strong impacts on the overall microbial composition and maturation of fecal microbiota in piglets during early life, and these effects were dependent on the growth stage. Oral administration of L. reuteri promoted diarrhea resistance in neonates, while maternal supplementation of L. reuteri enhanced the abilities of antioxidants and decreased inflammation. Moreover, the administration of L. reuteri via both methods in combination improved the growth performances of piglets.

CONCLUSION

Overall, our data demonstrated that L. reuteri had the ability to modulate the composition of fecal microbiota in newborn piglets by influencing the microbial community and functional composition in the colostrum and by altering several key metabolites in the umbilical cord blood serum. Also, both the maternal dietary supplementation and oral administration of L. reuteri effectively promoted the development and maturation of the fecal microbiome in piglets during early life. Both the maternal dietary supplementation and oral administration of L. reuteri in combination optimized the growth performances of piglets. Video Abstract.

Effects of a maternal mindfulness intervention targeting prenatal psychological distress on infants' meconium microbiota: A randomized controlled trial

BACKGROUND

Maternal psychological distress could affect gut microbiota of the infant; however, previous studies to date have been observational.

OBJECTIVE

To investigate the effects of mindfulness-based intervention (MBI) during pregnancy on the meconium microbiota of infants by alleviating maternal psychological distress.

DESIGN

Randomized controlled trial.

METHOD

Pregnant women with symptoms of depression or anxiety were randomized to either the intervention group (n = 80), comprising usual perinatal care and six digitally guided self-help MBI sessions, or the control group (n = 80) who underwent usual perinatal care. Meconium was collected within 48 h of birth to evaluate the infant's gut microbiota. The Kruskal-Wallis rank sum test, analysis of similarities, and DESeq2 were performed to explore the effects of the MBI on alpha and beta diversity indices and specific genera.

RESULTS

There were no significant differences between groups regarding the alpha diversity indices, including Chao1 and Simpson (p = 0.83 and p = 0.58). However, there was a significant between-group difference in the beta diversity index (R=0.02, p = 0.03). Bifidobacterium (log² fold change=-1.90, FDR=0.002) and Blautia (log² fold change=-1.45, FDR=0.01) were abundant in the intervention group, whereas Staphylococcus (log² fold change=1.44, FDR=0.01) was abundant in the control group.

CONCLUSIONS

MBI aimed at alleviating maternal psychological distress can positively alter the meconium microbiota of infants. However, the mechanisms underlying the effects of maternal mindfulness during pregnancy on infant meconium microbiota require further exploration.

Neonatal Programming of Microbiota Composition: A Plausible Idea That Is Not Supported by the Evidence

Underpinning the theory “developmental origins of health and disease” (DOHaD), evidence is accumulating to suggest that the risks of adult disease are in part programmed by exposure to environmental factors during the highly plastic “first 1,000 days of life” period. An elucidation of the mechanisms involved in this programming is challenging as it would help developing new strategies to promote adult health. The intestinal microbiome is proposed as a long-lasting memory of the neonatal environment. This proposal is supported by indisputable findings such as the concomitance of microbiota assembly and the first 1,000-day period, the influence of perinatal conditions on microbiota composition, and the impact of microbiota composition on host physiology, and is based on the widely held but unconfirmed view that the microbiota is long-lastingly shaped early in life. In this review, we examine the plausibility of the gut microbiota being programmed by the neonatal environment and evaluate the evidence for its validity. We highlight that the capacity of the pioneer bacteria to control the implantation of subsequent bacteria is supported by both theoretical principles and statistical associations, but remains to be demonstrated experimentally. In addition, our critical review of the literature on the long-term repercussions of selected neonatal modulations of the gut microbiota indicates that sustained programming of the microbiota composition by neonatal events is unlikely. This does not exclude the microbiota having a role in DOHaD due to a possible interaction with tissue and organ development during the critical windows of neonatal life.

Maternal consumption of a fermented diet protects offspring against intestinal inflammation by regulating the gut microbiota

The neonatal intestinal tract is immature and can be easily infected by pathogens causing inflammation. Maternal diet manipulation is a promising nutritional strategy to enhance the gut health of offspring. A fermented diet is a gut microbiota targeting diet containing live probiotics and their metabolites, which benefit the gut and overall health host. However, it remains unclear how a maternal fermented diet (MFD) affects neonatal intestinal inflammation. Here, in vivo and in vitro models together with multi-omics analysis were applied to investigate the impacts and the underlying mechanism through which an MFD prevents from gut inflammation in neonates. An MFD remarkably improved the performance of both sows and piglets and significantly altered the gut microbiome and milk metabolome of sows. In addition, the MFD significantly accelerated the maturation of the gut microbiota of neonates and increased the abundance of gut Lactobacillus and the microbial functions of amino acid-related enzymes and glucose metabolism on the weaning day. Notably, the MFD reduced susceptibility to colonic inflammation in offspring. The fecal microbiota of sows was then transplanted into mouse dams and it was found that the mouse dams and pups in the MFD group alleviated the LPS-induced decrease in gut Lactobacillus abundance and barrier injury. Milk L-glutamine (GLN) and gut Lactobacillus reuteri (LR) were found as two of the main MFD-induced sow effectors that contributed to the gut health of piglets. The properties of LR and GLN in modulating gut microbiota and alleviating colonic inflammation by inhibiting the phosphorylation of p38 and JNK and activation of Caspase 3 were further verified. These findings provide the first data revealing that an MFD drives neonate gut microbiota development and ameliorates the colonic inflammation by regulating the gut microbiota. This fundamental evidence might provide references for modulating maternal nutrition to enhance early-life gut health and prevent gut inflammation.

Composition of Human Breast Milk Microbiota and Its Role in Children's Health

Human milk contains a number of nutritional and bioactive molecules including microorganisms that constitute the so-called "Human Milk Microbiota (HMM)". Recent studies have shown that not only bacterial but also viral, fungal, and archaeal components are present in the HMM. Previous research has established, a "core" microbiome, consisting of Firmicutes (i.e., Streptococcus, Staphylococcus), Proteobacteria (i.e., Serratia, Pseudomonas, Ralstonia, Sphingomonas, Bradyrhizobium), and Actinobacteria (i.e., Propionibacterium, Corynebacterium). This review aims to summarize the main characteristics of HMM and the role it plays in shaping a child's health. We reviewed the most recent literature on the topic (2019-2021), using the PubMed database. The main sources of HMM origin were identified as the retrograde flow and the entero-mammary pathway. Several factors can influence its composition, such as maternal body mass index and diet, use of antibiotics, time and type of delivery, and mode of breastfeeding. The COVID-19 pandemic, by altering the mother-infant dyad and modifying many of our previous habits, has emerged as a new risk factor for the modification of HMM. HMM is an important contributor to gastrointestinal colonization in children and therefore, it is fundamental to avoid any form of perturbation in the HMM that can alter the microbial equilibrium, especially in the first 100 days of life. Microbial dysbiosis can be a trigger point for the development of necrotizing enterocolitis, especially in preterm infants, and for onset of chronic diseases, such as asthma and obesity, later in life.

Exclusively Breastfed Infant Microbiota Develops over Time and Is Associated with Human Milk Oligosaccharide Intakes

Temporal development of maternal and infant microbiomes during early life impacts short- and long-term infant health. This study aimed to characterize bacterial dynamics within maternal faecal, human milk (HM), infant oral, and infant faecal samples during the exclusive breastfeeding period and to document associations between human milk oligosaccharide (HMO) intakes and infant oral and faecal bacterial profiles. Maternal and infant samples (n = 10) were collected at 2−5, 30, 60, 90 and 120 days postpartum and the full-length 16S ribosomal RNA (rRNA) gene was sequenced. Nineteen HMOs were quantitated using high-performance liquid chromatography. Bacterial profiles were unique to each sample type and changed significantly over time, with a large degree of intra- and inter-individual variation in all sample types. Beta diversity was stable over time within infant faecal, maternal faecal and HM samples, however, the infant oral microbiota at day 2−5 significantly differed from all other time points (all p < 0.02). HMO concentrations and intakes significantly differed over time, and HMO intakes showed differential associations with taxa observed in infant oral and faecal samples. The direct clinical relevance of this, however, is unknown. Regardless, future studies should account for intakes of HMOs when modelling the impact of HM on infant growth, as it may have implications for infant microbiota development.

Altered Gut Structure and Anti-Bacterial Defense in Adult Mice Treated with Antibiotics during Early Life

The association between prolonged antibiotic (AB) use in neonates and increased incidence of later life diseases is not yet fully understood. AB treatment in early life alters intestinal epithelial cell composition, functioning, and maturation, which could be the basis for later life health effects. Here, we investigated whether AB-induced changes in the neonatal gut persisted up to adulthood and whether early life AB had additional long-term consequences for gut functioning. Mice received AB orally from postnatal day 10 to 20. Intestinal morphology, permeability, and gene and protein expression at 8 weeks were analyzed. Our data showed that the majority of the early life AB-induced gut effects did not persist into adulthood, yet early life AB did impact later life gut functioning. Specifically, the proximal small intestine (SI) of adult mice treated with AB in early life was characterized by hyperproliferative crypts, increased number of Paneth cells, and alterations in enteroendocrine cell-specific gene expression profiles. The distal SI of adult mice displayed a reduced expression of antibacterial defense markers. Together, our results suggest that early life AB leads to structural and physiological changes in the adult gut, which may contribute to disease development when homeostatic conditions are under challenge.

The Developing Microbiome From Birth to 3 Years: The Gut-Brain Axis and Neurodevelopmental Outcomes

The volume and breadth of research on the role of the microbiome in neurodevelopmental and neuropsychiatric disorders has expanded greatly over the last decade, opening doors to new models of mechanisms of the gut-brain axis and therapeutic interventions to reduce the burden of these outcomes. Studies have highlighted the window of birth to 3 years as an especially sensitive window when interventions may be the most effective. Harnessing the powerful gut-brain axis during this critical developmental window clarifies important investigations into the microbe-human connection and the developing brain, affording opportunities to prevent rather than treat neurodevelopmental disorders and neuropsychiatric illness. In this review, we present an overview of the developing intestinal microbiome in the critical window of birth to age 3; and its prospective relationship with neurodevelopment, with particular emphasis on immunological mechanisms. Next, the role of the microbiome in neurobehavioral outcomes (such as autism, anxiety, and attention-deficit hyperactivity disorder) as well as cognitive development are described. In these sections, we highlight the importance of pairing mechanistic studies in murine models with large scale epidemiological studies that aim to clarify the typical health promoting microbiome in early life across varied populations in comparison to dysbiosis. The microbiome is an important focus in human studies because it is so readily alterable with simple interventions, and we briefly outline what is known about microbiome targeted interventions in neurodevelopmental outcomes. More novel examinations of known environmental chemicals that adversely impact neurodevelopmental outcomes and the potential role of the microbiome as a mediator or modifier are discussed. Finally, we look to the future and emphasize the need for additional research to identify populations that are sensitive to alterations in their gut microbiome and clarify how interventions might correct and optimize neurodevelopmental outcomes.

Short- and long-term effects of amoxicillin/clavulanic acid or doxycycline on the gastrointestinal microbiome of growing cats

Antibiotic treatment in early life influences gastrointestinal (GI) microbial composition and function. In humans, the resultant intestinal dysbiosis is associated with an increased risk for certain diseases later in life. The objective of this study was to determine the temporal effects of antibiotic treatment on the GI microbiome of young cats. Fecal samples were collected from cats randomly allocated to receive either amoxicillin/clavulanic acid (20 mg/kg q12h) for 20 days (AMC group; 15 cats) or doxycycline (10 mg/kg q24h) for 28 days (DOX group;15 cats) as part of the standard treatment of upper respiratory tract infection. In addition, feces were collected from healthy control cats (CON group;15 cats). All cats were approximately two months of age at enrolment. Samples were collected on days 0 (baseline), 20 or 28 (AMC and DOX, respectively; last day of treatment), 60, 120, and 300. DNA was extracted and sequencing of the 16S rRNA gene and qPCR assays were performed. Fecal microbial composition was different on the last day of treatment for AMC cats, and 1 month after the end of antibiotic treatment for DOX cats, compared to CON cats. Species richness was significantly greater in DOX cats compared to CON cats on the last day of treatment. Abundance of Enterobacteriales was increased, and that of Erysipelotrichi was decreased in cats of the AMC group on the last day of treatment compared to CON cats. The abundance of the phylum Proteobacteria was increased in cats of the DOX group on days 60 and 120 compared to cats of the CON group. Only minor differences in abundances between the treatment groups and the control group were present on day 300. Both antibiotics appear to delay the developmental progression of the microbiome, and this effect is more profound during treatment with amoxicillin/clavulanic acid and one month after treatment with doxycycline. Future studies are required to determine if these changes influence microbiome function and whether they have possible effects on disease susceptibility in cats.

Short- and Long-Term Implications of Human Milk Microbiota on Maternal and Child Health

Human milk (HM) is considered the most complete food for infants as its nutritional composition is specifically designed to meet infant nutritional requirements during early life. HM also provides numerous biologically active components, such as polyunsaturated fatty acids, milk fat globules, IgA, gangliosides or polyamines, among others; in addition, HM has a “bifidogenic effect”, a prebiotic effect, as a result of the low concentration of proteins and phosphates, as well as the presence of lactoferrin, lactose, nucleotides and oligosaccharides. Recently, has been a growing interest in HM as a potential source of probiotics and commensal bacteria to the infant gut, which might, in turn, influence both the gut colonization and maturation of infant immune system. Our review aims to address practical approaches to the detection of microbial communities in human breast milk samples, delving into their origin, composition and functions. Furthermore, we will summarize the current knowledge of how HM microbiota dysbiosis acts as a short- and long-term predictor of maternal and infant health. Finally, we also provide a critical view of the role of breast milk-related bacteria as a novel probiotic strategy in the prevention and treatment of maternal and offspring diseases.

Human Milk Oligosaccharide-Stimulated Bifidobacterium Species Contribute to Prevent Later Respiratory Tract Infections

(1) Background: Human milk oligosaccharides (HMOs) may support immune protection, partly via their action on the early-life gut microbiota. Exploratory findings of a randomized placebo-controlled trial associated 2′fucosyllactose (2′FL) and lacto-N-neotetraose (LNnT) formula feeding with reduced risk for reported bronchitis and lower respiratory tract illnesses (LRTI), as well as changes in gut microbiota composition. We sought to identify putative gut microbial mechanisms linked with these clinical observations. (2) Methods: We used stool microbiota composition, metabolites including organic acids and gut health markers in several machine-learning-based classification tools related prospectively to experiencing reported bronchitis or LRTI, as compared to no reported respiratory illness. We performed preclinical epithelial barrier function modelling to add mechanistic insight to these clinical observations. (3) Results: Among the main features discriminant for infants who did not experience any reported bronchitis (n = 80/106) or LRTI (n = 70/103) were the 2-HMO formula containing 2′FL and LNnT, higher acetate, fucosylated glycans and Bifidobacterium, as well as lower succinate, butyrate, propionate and 5-aminovalerate, along with Carnobacteriaceae members and Escherichia. Acetate correlated with several Bifidobacterium species. By univariate analysis, infants experiencing no bronchitis or LRTI, compared with those who did, showed higher acetate (p < 0.007) and B. longum subsp. infantis (p ≤ 0.03). In vitro experiments demonstrate that 2′FL, LNnT and lacto-N-tetraose (LNT) stimulated B. longum subsp. infantis (ATCC15697) metabolic activity. Metabolites in spent culture media, primarily due to acetate, supported epithelial barrier protection. (4) Conclusions: An early-life gut ecology characterized by Bifidobacterium-species-driven metabolic changes partly explains the observed clinical outcomes of reduced risk for bronchitis and LRTI in infants fed a formula with HMOs. (Trial registry number NCT01715246.).

25 Years of Research in Human Lactation: From Discovery to Translation

Researchers have recently called for human lactation research to be conceptualized as a biological framework where maternal and infant factors impacting human milk, in terms of composition, volume and energy content are studied along with relationships to infant growth, development and health. This approach allows for the development of evidence-based interventions that are more likely to support breastfeeding and lactation in pursuit of global breastfeeding goals. Here we summarize the seminal findings of our research programme using a biological systems approach traversing breast anatomy, milk secretion, physiology of milk removal with respect to breastfeeding and expression, milk composition and infant intake, and infant gastric emptying, culminating in the exploration of relationships with infant growth, development of body composition, and health. This approach has allowed the translation of the findings with respect to education, and clinical practice. It also sets a foundation for improved study design for future investigations in human lactation.

Galacto-oligosaccharides improve barrier function and relieve colonic inflammation via modulating mucosa-associated microbiota composition in lipopolysaccharides-challenged piglets

BACKGROUND

Galacto-oligosaccharides (GOS) have been shown to modulate the intestinal microbiota of suckling piglets to exert beneficial effects on intestinal function. However, the modulation of intestinal microbiota and intestinal function by GOS in intestinal inflammation injury models has rarely been reported. In this study, we investigated the effects of GOS on the colonic mucosal microbiota composition, barrier function and inflammatory response of lipopolysaccharides (LPS)-challenged suckling piglets.

METHODS

A total of 18 newborn suckling piglets were divided into three groups, the CON group, the LPS-CON group and the LPS-GOS group. Piglets in the LPS-GOS group were orally fed with 1 g/kg body weight of GOS solution every day. On the d 14, piglets in the LPS-CON and LPS-GOS group were challenged intraperitoneally with LPS solution. All piglets were slaughtered 2 h after intraperitoneal injection and sampled.

RESULTS

We found that the colonic mucosa of LPS-challenged piglets was significantly injured and shedding, while the colonic mucosa of the LPS-GOS group piglets maintained its structure. Moreover, GOS significantly reduced the concentration of malondialdehyde (MDA) and the activity of reactive oxygen species (ROS) in the LPS-challenged suckling piglets, and significantly increased the activity of total antioxidant capacity (T-AOC). GOS significantly increased the relative abundance of norank_f__Muribaculaceae and Romboutsia, and significantly decreased the relative abundance of Alloprevotella, Campylobacter and Helicobacter in the colonic mucosa of LPS-challenged suckling piglets. In addition, GOS increased the concentrations of acetate, butyrate and total short chain fatty acids (SCFAs) in the colonic digesta of LPS-challenged suckling piglets. GOS significantly reduced the concentrations of interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α) and cluster of differentiation 14 (CD14), and the relative mRNA expression of Toll-like receptor 4 (TLR4) and myeloid differentiation primary response 88 (MyD88) in the LPS-challenged suckling piglets. In addition, GOS significantly reduced the relative mRNA expression of mucin2 (MUC2), and significantly increased the protein expression of Claudin-1 and zonula occluden-1 (ZO-1) in LPS-challenged suckling piglets.

CONCLUSIONS

These results suggested that GOS can modulate the colonic mucosa-associated microbiota composition and improve the intestinal function of LPS-challenged suckling piglets.

Early-life gut microbiota and its connection to metabolic health in children: Perspective on ecological drivers and need for quantitative approach

The colonisation and development of the gut microbiota has been implicated in paediatric metabolic disorders via its powerful effect on host metabolic and immune homeostasis. Here we summarise the evidence from human studies on the early gut microbiota and paediatric overweight and obesity. Manipulation of the early gut microbiota may represent a promising target for countering the burgeoning metabolic disorders in the paediatric population, provided the assembly patterns of microbiota and their health consequences can be decoded. Therefore, in this review, we pay particular attention to the important ecological drivers affecting the community dynamics of the early gut microbiota. We then discuss the knowledge gaps in commonly studied exposures linking the gut microbiota to metabolic disorders, especially regarding maternal factors and antibiotic use. This review also attempts to give directions for future studies aiming to identify predictive and corrective measures for paediatric metabolic disorders based on the gut microbiota. Gut microbiota; Metabolism; Paediatric overweight and obesity; Ecological driver; Dynamics; Infants.

Breastfeeding Beyond 12 Months: Is There Evidence for Health Impacts?

Because breastfeeding provides optimal nutrition and other benefits for infants (e.g., lower risk of infectious disease) and benefits for mothers (e.g., less postpartum bleeding), health organizations recommend that healthy infants be exclusively breastfed for 4 to 6 months in the United States and 6 months internationally. Recommendations related to how long breastfeeding should continue, however, are inconsistent. The objective of this article is to review the literature related to evidence for benefits of breastfeeding beyond 1 year for mothers and infants. In summary, human milk represents a good source of nutrients and immune components beyond 1 year. Some studies point toward lower infant mortality in undernourished children breastfed for >1 year, and prolonged breastfeeding increases interbirth intervals. Data on other outcomes (e.g., growth, diarrhea, obesity, and maternal weight loss) are inconsistent, often lacking sufficient control for confounding variables. There is a substantial need for rigorous, prospective, mixed-methods, cross-cultural research on this topic. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Development of the infant gut microbiome predicts temperament across the first year of life

Perturbations to the gut microbiome are implicated in altered neurodevelopmental trajectories that may shape life span risk for emotion dysregulation and affective disorders. However, the sensitive periods during which the microbiome may influence neurodevelopment remain understudied. We investigated relationships between gut microbiome composition across infancy and temperament at 12 months of age. In 67 infants, we examined if gut microbiome composition assessed at 1-3 weeks, 2, 6, and 12 months of age was associated with temperament at age 12 months. Stool samples were sequenced using the 16S Illumina MiSeq platform. Temperament was assessed using the Infant Behavior Questionnaire-Revised (IBQ-R). Beta diversity at age 1-3 weeks was associated with surgency/extraversion at age 12 months. Bifidobacterium and Lachnospiraceae abundance at 1-3 weeks of age was positively associated with surgency/extraversion at age 12 months. Klebsiella abundance at 1-3 weeks was negatively associated with surgency/extraversion at 12 months. Concurrent composition was associated with negative affectivity at 12 months, including a positive association with Ruminococcus-1 and a negative association with Lactobacillus. Our findings support a relationship between gut microbiome composition and infant temperament. While exploratory due to the small sample size, these results point to early and late infancy as sensitive periods during which the gut microbiome may exert effects on neurodevelopment.

Human milk composition promotes optimal infant growth, development and health

Human milk is a living dynamic fluid that promotes optimal nutrition and development of the infant and impacts health across the lifespan. This review reports on the diverse range of nutrients, immune protection factors, hormones, microbes and metabolites in human milk and their impacts on infant nutrition and health. While many of these components are stable across lactation and similar between women, some vary over time, and in response to maternal and infant health status, maternal diet and geographic location. Human milk may be considered as personalized nutrition, with many components working synergistically to stimulate and support the infant's immature immune system, while enhancing appropriate development, growth and body composition.

Comparing different sample collection and storage methods for field-based skin microbiome research

OBJECTIVES

The skin, as well as its microbial communities, serves as the primary interface between the human body and the surrounding environment. In order to implement the skin microbiome into human biology research, there is a need to explore the effects of different sample collection and storage methodologies, including the feasibility of conducting skin microbiome studies in field settings.

METHODS

We collected 99 skin microbiome samples from nine infants living in Veracruz, Mexico using a dual-tipped "dry" swab on the right armpit, palm, and forehead and a "wet" swab (0.15 M NaCl and 0.1% Tween 20) on the same body parts on the left side of the body. One swab from each collection method was stored in 95% ethanol while the other was frozen at -20°C. 16S rRNA amplicon sequencing generated data on bacterial diversity and community composition, which were analyzed using PERMANOVA, linear mixed effects models, and an algorithm-based classifier.

RESULTS

Treatment (wet_ethanol, wet_freezer, dry_ethanol, and dry_freezer) had an effect (~10% explanatory power) on the bacterial community diversity and composition of skin samples, although body site exhibited a stronger effect (~20% explanatory power). Within treatments, the collection method (wet vs. dry) affected measures of bacterial diversity to a greater degree than did the storage method (ethanol vs. freezer).

CONCLUSIONS

Our study provides novel information on skin microbiome sample collection and storage methods, suggesting that ethanol storage is suitable for research in resource-limited settings. Our results highlight the need for future study design to account for interbody site microbial variation.

Season-of-birth phenomenon in health and longevity: epidemiologic evidence and mechanistic considerations

In many human populations, especially those living in regions with pronounced climatic differences between seasons, the most sensitive (prenatal and neonatal) developmental stages occur in contrasting conditions depending on the season of conception. The difference in prenatal and postnatal environments may be a factor significantly affecting human development and risk for later life chronic diseases. Factors potentially contributing to this kind of developmental programming include nutrition, outdoor temperature, infectious exposures, duration of sunlight, vitamin D synthesis, etc. Month of birth is commonly used as a proxy for exposures which vary seasonally around the perinatal period. Season-of-birth patterns have been identified for many chronic health outcomes. In this review, the research evidence for the seasonality of birth in adult-life disorders is provided and potential mechanisms underlying the phenomenon of early life seasonal programming of chronic disease and longevity are discussed.

Determinants of Breastfeeding Practices and Its Association With Infant Anthropometry: Results From a Prospective Cohort Study in South India

Introduction

Despite national efforts for promoting exclusive breastfeeding (EBF) during the first 6 months of the infants' life, breastfeeding rates are low in India. Evidence on the interference of supplementary food on optimal nourishment and growth of the infant has also been well-established. Our study was undertaken to assess the effect of breastfeeding practices on infant anthropometry and determine the various factors affecting breastfeeding practices.

Methods

A prospective cohort study - Maternal antecedents of adiposity and studying the transgenerational role of hyperglycemia and insulin (MAASTHI) was conducted at a tertiary care public hospital in Bengaluru, South India. From the consenting women, data such as obstetric history, infant feeding practices, anthropometry of mother and child, the psychosocial status of the women using the Edinburgh Postnatal Depression Scale (EPDS), was collected at baseline and subsequent follow-up: post-delivery and 14 weeks after birth. In this study, we analyzed data collected from April 2016 to April 2018, with descriptive statistics presented in mean and standard deviation, and logistic regression adjusting for confounders.

Results

Among the 240 women enrolled in the study, 33% (n= 80) were using supplementary food for their infants at 14 weeks of infants age. Infants who received supplementary feeding at age 14 weeks had nearly 2.5 times higher odds of being wasted (OR: 2.449, p-value: 0.002) as compared to exclusively breastfed infants.

Conclusion

Infants between 14 to 16 weeks of age who received supplementary feeding were at risk of wasting as compared to exclusively breastfed infants. Despite strong evidence in support of the benefits of exclusive breastfeeding, awareness in urban women in India is low. Increased focus on promoting exclusive breastfeeding is necessary to ensure proper nutritional intake and healthy growth of infants.

CNS Macrophages and Infant Infections

The central nervous system (CNS) harbors its own immune system composed of microglia in the parenchyma and CNS-associated macrophages (CAMs) in the perivascular space, leptomeninges, dura mater, and choroid plexus. Recent advances in understanding the CNS resident immune cells gave new insights into development, maturation and function of its immune guard. Microglia and CAMs undergo essential steps of differentiation and maturation triggered by environmental factors as well as intrinsic transcriptional programs throughout embryonic and postnatal development. These shaping steps allow the macrophages to adapt to their specific physiological function as first line of defense of the CNS and its interfaces. During infancy, the CNS might be targeted by a plethora of different pathogens which can cause severe tissue damage with potentially long reaching defects. Therefore, an efficient immune response of infant CNS macrophages is required even at these early stages to clear the infections but may also lead to detrimental consequences for the developing CNS. Here, we highlight the recent knowledge of the infant CNS immune system during embryonic and postnatal infections and the consequences for the developing CNS.

Structure and Function of Bovine Whey Derived Oligosaccharides Showing Synbiotic Epithelial Barrier Protective Properties

Commensal gut microbiota and probiotics have numerous effects on the host’s metabolic and protective systems, which occur primarily through the intestinal epithelial cell interface. Prebiotics, like galacto-oligosaccharides (GOS) are widely used to modulate their function and abundance. However, important structure–function relations may exist, requiring a detailed structural characterization. Here, we detailed the structural characterization of bovine whey derived oligosaccharide preparations enriched with GOS or not, dubbed GOS-enriched milk oligosaccharides (GMOS) or MOS, respectively. We explore GMOS’s and MOS’s potential to improve intestinal epithelial barrier function, assessed in a model based on barrier disruptive effects of the Clostridioides difficile toxin A. GMOS and MOS contain mainly GOS species composed of β1-6- and β1-3-linked galactoses, and 3′- and 6′-sialyllactose. Both GMOS and MOS, combined with lactobacilli, like Lactobacillus rhamnosus (LPR, NCC4007), gave synergistic epithelial barrier protection, while no such effect was observed with Bifidobacterium longum (BL NCC3001), Escherichia coli (Nissle) or fructo-oligosaccharides. Mechanistically, for barrier protection with MOS, (i) viable LPR was required, (ii) acidification of growth medium was not enough, (iii) LPR did not directly neutralize toxin A, and (iv) physical proximity of LPR with the intestinal epithelial cells was necessary. This is the first study, highlighting the importance of structure–function specificity and the necessity of the simultaneous presence of prebiotic, probiotic and host cell interactions required for a biological effect.