The Prebiotic and Probiotic Properties of Human Milk: Implications for Infant Immune Development and Pediatric Asthma

Priority effects alter microbiome composition and increase abundance of probiotic taxa in treefrog tadpoles

Host-associated microbial communities, like other ecological communities, may be impacted by the colonization order of taxa through priority effects. Developing embryos and their associated microbiomes are subject to stochasticity during colonization by bacteria. For amphibian embryos, often developing externally in bacteria-rich environments, this stochasticity may be particularly impactful. For example, the amphibian microbiome can mitigate lethal outcomes from disease for their hosts; however, this may depend on microbiome composition. Here, we examined the assembly of the bacterial community in spring peeper (Pseudacris crucifer) embryos and tadpoles. First, we reared embryos from identified mating pairs in either lab or field environments to examine the relative impact of environment and parentage on embryo and tadpole bacterial communities. Second, we experimentally inoculated embryos to determine if priority effects (i) could be used to increase the relative abundance of Janthinobacterium lividum, an amphibian-associated bacteria capable of preventing fungal infection, and (ii) would lead to observed differences in the relative abundances of two closely related bacteria from the genus Pseudomonas. Using 16S rRNA gene amplicon sequencing, we observed differences in community composition based on rearing location and parentage in embryos and tadpoles. In the inoculation experiment, we found that priority inoculation could increase the relative abundance of J. lividum, but did not find that either Pseudomonas isolate was able to prevent colonization by the other when given priority. These results highlight the importance of environmental source pools and parentage in determining microbiome composition, while also providing novel methods for the administration of a known amphibian probiotic.

IMPORTANCE

Harnessing the functions of host-associated bacteria is a promising mechanism for managing disease outcomes across different host species. In the case of amphibians, certain frog-associated bacteria can mitigate lethal outcomes of infection by the fungal pathogen Batrachochytrium dendrobatidis. Successful probiotic applications require knowledge of community assembly and an understanding of the ecological mechanisms that structure these symbiotic bacterial communities. In our study, we show the importance of environment and parentage in determining bacterial community composition and that community composition can be influenced by priority effects. Further, we provide support for the use of bacterial priority effects as a mechanism to increase the relative abundance of target probiotic taxa in a developing host. While our results show that priority effects are not universally effective across all host-associated bacteria, our ability to increase the relative abundance of specific probiotic taxa may enhance conservation strategies that rely on captive rearing of endangered vertebrates.

The Role of the Microbiota in the Pathogenesis and Treatment of Atopic Dermatitis-A Literature Review

Atopic dermatitis (AD) is a chronic inflammatory skin condition with a high prevalence worldwide. AD pathogenesis is complex and consists of immune system dysregulation and impaired skin barrier, influenced by genetic and environmental factors. The purpose of the review is to show the complex interplay between atopic dermatitis and the microbiota. Human microbiota plays an important role in AD pathogenesis and the course of the disease. Dysbiosis is an important factor contributing to the development of atopic diseases, including atopic dermatitis. The gut microbiota can influence the composition of the skin microbiota, strengthening the skin barrier and regulating the immune response via the involvement of bacterial metabolites, particularly short-chain fatty acids, in signaling pathways of the gut-skin axis. AD can be modulated by antibiotic intake, dietary adjustments, hygiene, and living conditions. One of the promising strategies for modulating the course of AD is probiotics. This review offers a summary of how the microbiota influences the development and treatment of AD, highlighting aspects that warrant additional investigation.

Maternal Diet Associated with Oligosaccharide Abundances in Human Milk from Latina Mothers

Growing evidence indicates that human milk oligosaccharides (HMOs) are important bioactive compounds that enhance health and developmental outcomes in breastfed babies. Maternal dietary intake likely contributes to variation in HMO composition, but studies identifying diet-HMO relationships are few and inconsistent. This study aimed to investigate how the maternal intake of macronutrients and micronutrients-specifically proteins, fats, vitamins, and minerals-associated with HMOs at 1 month (n = 210), 6 months (n = 131), and 12 months postpartum (n = 84). Several associations between maternal dietary factors and HMO profiles were identified utilizing partial correlation analysis. For example, maternal free sugar (rho = -0.02, p < 0.01), added sugar (rho = -0.22, p < 0.01), and sugary sweetened beverage (rho = -0.22, p < 0.01) intake were negatively correlated with the most abundant HMO, 2'-fucosyllactose (2'-FL), at 1 month, suggesting that higher sugar consumption was associated with reduced levels of 2'-FL. Further, vitamins D, C, K, and the minerals zinc and potassium were positively correlated with 2'-FL at 1 month (pAll < 0.05). For the longitudinal analysis, a mixed-effects linear regression model revealed significant associations between maternal vitamin intake and HMO profiles over time. For example, for each unit increase in niacin intake, there was a 31.355 nmol/mL increase in 2'-FL concentration (p = 0.03). Overall, the results provide additional evidence supporting a role for maternal nutrition in shaping HMO profiles, which may inform future intervention strategies with the potential of improving infant growth and development through optimal HMO levels in mothers' milk.

Science and Faith to Understand Milk Bioactivity for Infants

Milk bioactivity refers to the specific health effects of milk components beyond nutrition. The science of milk bioactivity involves the systematic study of these components and their health effects, as verified by empirical data, controlled experiments, and logical arguments. Conversely, 'faith in milk bioactivity' can be defined as personal opinion, meaning, value, trust, and hope for health effects that are beyond investigation by natural, social, or human sciences. Faith can be strictly secular, but also influenced by spirituality or religion. The aim of this paper is to show that scientific knowledge is frequently supplemented with faith convictions to establish personal and public understanding of milk bioactivity. Mammalian milk is an immensely complex fluid containing myriad proteins, carbohydrates, lipids, and micronutrients with multiple functions across species, genetics, ages, environments, and cultures. Human health includes not only physical health, but also social, mental, and spiritual health, requiring widely different fields of science to prove the relevance, safety, and efficacy of milk interventions. These complex relationships between milk feeding and health outcomes prevent firm conclusions based on science and logic alone. Current beliefs in and understanding of the value of breast milk, colostrum, infant formula, or isolated milk proteins (e.g., immunoglobulins, α-lactalbumin, lactoferrin, and growth factors) show that both science and faith contribute to understand, stimulate, or restrict the use of milk bioactivity. The benefits of breastfeeding for infants are beyond doubt, but the strong beliefs in its health effects rely not only on science, and mechanisms are unclear. Likewise, fear of, or trust in, infant formula may rely on both science and faith. Knowledge from science safeguards individuals and society against 'milk bioactivity superstition'. Conversely, wisdom from faith-based convictions may protect science from unrealistic 'milk bioactivity scientism'. Honesty and transparency about the potentials and limitations of both scientific knowledge and faith convictions are important when informing individuals and society about the nutritious and bioactive qualities of milk.

Nurturing development: how a mother's nutrition shapes offspring's brain through the gut

Pregnancy is a transformative period marked by profound physical and emotional changes, with far-reaching consequences for both mother and child. Emerging research has illustrated the pivotal role of a mother's diet during pregnancy in influencing the prenatal gut microbiome and subsequently shaping the neurodevelopment of her offspring. The intricate interplay between maternal gut health, nutrition, and neurodevelopmental outcomes has emerged as a captivating field of investigation within developmental science. Acting as a dynamic bridge between mother and fetus, the maternal gut microbiome, directly and indirectly, impacts the offspring's neurodevelopment through diverse pathways. This comprehensive review delves into a spectrum of studies, clarifying putative mechanisms through which maternal nutrition, by modulating the gut microbiota, orchestrates the early stages of brain development. Drawing insights from animal models and human cohorts, this work underscores the profound implications of maternal gut health for neurodevelopmental trajectories and offers a glimpse into the formulation of targeted interventions able to optimize the health of both mother and offspring. The prospect of tailored dietary recommendations for expectant mothers emerges as a promising and accessible intervention to foster the growth of beneficial gut bacteria, potentially leading to enhanced cognitive outcomes and reduced risks of neurodevelopmental disorders.

Human Breast Milk: The Role of Its Microbiota and Metabolites in Infant Health

This review explores the role of microorganisms and metabolites in human breast milk and their impact on neonatal health. Breast milk serves as both a primary source of nutrition for newborns and contributes to the development and maturation of the digestive, immunological, and neurological systems. It has the potential to reduce the risks of infections, allergies, and asthma. As our understanding of the properties of human milk advances, there is growing interest in incorporating its benefits into personalized infant nutrition strategies, particularly in situations in which breastfeeding is not an option. Future infant formula products are expected to emulate the composition and advantages of human milk, aligning with an evolving understanding of infant nutrition. The long-term health implications of human milk are still under investigation.

Efficacy and safety of a synbiotic infant formula for the prevention of respiratory and gastrointestinal infections: a randomized controlled trial

BACKGROUND

Early life nutrition is crucial for the development of the gut microbiota that, in turn, plays an essential role in the maturation of the immune system and the prevention of infections.

OBJECTIVES

The aim of this study was to investigate whether feeding synbiotic infants and follow-on formulas during the first year of life reduces the incidence rate (IR) of infectious diarrhea compared with standard formulas. Secondary endpoints included the IR of other infectious diseases as well as fecal milieu parameters.

METHODS

In this double-blind, controlled trial, 460 healthy, 1-mo-old infants were randomly assigned to receive a synbiotic [galacto-oligosaccharides (GOS)/Limosilactobacillus fermentum CECT 5716] (IF, n = 230) or a control formula (CF, n = 230) until 12 mo of age. A reference group of breastfed infants (HM, n = 80) was included. Data on infections were recorded throughout the study period and stool samples were collected at 4 and 12 mo of age.

RESULTS

IR of infectious diarrhea during the first year of life was 0.60 (CF), 0.56 (IF), and 0.29 (HM), with no statistically significant difference between groups. The IR of lower respiratory tract infections, 1 of the secondary endpoints, however, was lower in IF than in CF [0.79 compared with 1.01, IR ratio = 0.77 (0.60-1.00)]. Additionally, fecal pH was significantly lower at 4 mo (P < 0.0001), whereas secretory IgA was significantly higher at 12 mo of age (P = 0.015) in IF compared with CF.

CONCLUSIONS

Although no difference is observed in the incidence of diarrhea, consumption of a synbiotic formula containing L. fermentum CECT5716 and GOS in infancy may reduce the incidence of lower respiratory tract infections and affect the immune system and fecal milieu. Additional research is warranted to further investigate the potential interaction of the gut-lung axis. This trial was registered at clinicaltrials.gov as NCT02221687.

Supplementation of Heat-Treated Lactiplantibacillus plantarum nF1 Changes the Production of Short-Chain Fatty Acids in Healthy Infants

Background

Imbalance of the gut microbiome and decrease in the number of short-chain fatty acid (SCFA)-producing bacteria often affect human health by altering intestinal and immune homeostasis. The use of probiotics has been shown to be an attractive method to modulate gut microbiota to prevent or treat intestinal dysbiosis. Likewise, this study aimed to determine whether the oral consumption of heat-treated Lactiplantibacillus plantarum nF1 (HLp-nF1) induces changes in the gut environment in healthy infants by measuring changes in fecal SCFAs.

Methods

The study enrolled 43 infants aged under 2 months, with 30 infants in the HLp-nF1 group receiving HLp-nF1 orally (2.5 × 1010 cells/g/pack, daily dose of two packs) for 8 weeks. The fecal samples were collected and the questionnaires were administered at weeks 0 and 8.

Results

The concentrations of the total SCFAs, acetate, propionate, and butyrate significantly increased following HLp-nF1 supplementation (P < 0.0001, P < 0.0001, P < 0.0001, and P=0.028, respectively).

Conclusions

Supplementation of HLp-nF1 has a positive effect on SCFA production and could be a potentially useful and straightforward method to manipulate SCFA formation.

Exploring Anti-Breast Cancer Effects of Live Pediococcus acidilactici and Its Cell-Free Supernatant Isolated from Human Breast Milk

Current breast cancer treatment options are limited by drug resistance and adverse side effects, which calls for the need for alternatives or complementary remedies. Probiotic bacteria isolated from human breast milk have been shown to possess proapoptotic and anti-inflammatory properties against breast mastitis in breastfeeding mothers and are being studied as possible anticancer regimens. Thus, this study aimed at exploring the effect of lactic acid bacteria isolated from human breast milk on MDA-MB 231 breast cancer cells. A total of twenty-two bacteria were isolated from four human breast milk samples. The isolates were characterized and identified using biochemical tests and Sanger sequencing, respectively. For in vitro experiments, we used isolated P. acidilactici to treat MDA-MB-231 cells, and an MTT assay was used to detect proliferation. RT-qPCR and wound healing assays were performed to determine the effect of the isolated P. acidilactici on breast cancer cytokine expression and migration. Exposure of MDA-MB 231 breast cancer cells to live P. acidilactici and its cell-free supernatant (CFS) for 24 h resulted in a reduction in cancer cell viability. Also, the expression of the cytokines IL-6, IL-8, and IL-10 in the breast cancer cells increased following exposure to P. acidilactici and its CFS for 24 and 72 h. Additionally, the levels of the SLUG gene remained unchanged while the TWIST1 gene was upregulated following exposure of the cancer cells to bacteria, indicating that P. acidilactici may promote epithelial-mesenchymal transition in breast cancer. Finally, the CFS significantly inhibited cancer cell mobility. These findings serve as a foundation to further investigate the usefulness of P. acidilactici as a potential therapeutic agent in breast cancer therapy.

Establishment of oral microbiome in very low birth weight infants during the first weeks of life and the impact of oral diet implementation

Very low birth weight (VLBW) infants, mostly preterm, have many barriers to feeding directly from the mother's breast, and need to be fed alternatively. Feeding is a major influencer in oral microbial colonization, and this colonization in early life is crucial for the promotion of human health. Therefore, this research aimed to observe the establishment of oral microbiome in VLBW infants during their first month of life through hospitalization, and to verify the impact caused by the implementation of oral diet on the colonization of these newborns. We included 23 newborns followed during hospitalization and analyzed saliva samples collected weekly, using 16S rRNA gene sequencing. We observed a significant decrease in richness and diversity and an increase in dominance over time (q-value < 0.05). The oral microbiome is highly dynamic during the first weeks of life, and beta diversity suggests a microbial succession in early life. The introduction of oral diet does not change the community structure, but affects the abundance, especially of Streptococcus. Our results indicate that although time is related to significant changes in the oral microbial profile, oral feeding benefits genera that will remain colonizers throughout the host's life.

Early-immune development in asthma: A review of the literature

This review presents a comprehensive examination of the various factors contributing to the immunopathogenesis of asthma from the prenatal to preschool period. We focus on the contributions of genetic and environmental components as well as the role of the nasal and gut microbiome on immune development. Predisposing genetic factors, including inherited genes associated with increased susceptibility to asthma, are discussed alongside environmental factors such as respiratory viruses and pollutant exposure, which can trigger or exacerbate asthma symptoms. Furthermore, the intricate interplay between the nasal and gut microbiome and the immune system is explored, emphasizing their influence on allergic immune development and response to environmental stimuli. This body of literature underscores the necessity of a comprehensive approach to comprehend and manage asthma, as it emphasizes the interactions of multiple factors in immune development and disease progression.

Causal relationship between Butyricimonas and allergic asthma: a two-sample Mendelian randomization study

Background

Growing evidence has well documented the close association between the gut microbiome and allergic respiratory disease, which has been notably represented by allergic asthma. However, it is unclear whether this association is a causal link. Therefore, we investigated the potential causal associations between the gut microbiome and allergic asthma or other allergic diseases.

Methods

In this study, we performed two-sample Mendelian randomization (MR) analyses by using the publicly available genome-wide association study (GWAS) summary data. Single-nucleotide polymorphisms (SNPs) that significantly correlated were selected as instrumental variables. The inverse variance weighted (IVW) method was used to examine the potential causal gut microbial genera for allergic asthma and other allergic diseases. The robustness of the primary findings of the MR analyses was ensured by using different sensitivity analyses.

Results

Combining the findings from multiple analyses, the host genetic-driven increases in Butyricimonas at the genus level were positively correlated with the risk of allergic asthma. In addition, phylum Bacteroidetes and class Bacteroidia were also found to have negative associations with the risk of allergic asthma; genus Slackia was identified as having potential causal effects with allergic asthma. No clear evidence of pleiotropy and heterogeneity was observed in genus Butyricimonas. Butyricimonas was also found to have an association with allergic rhinitis, but not with other allergic diseases.

Conclusion

Our findings indicate that there are new gut microbial genera that were causally associated with the risk of allergic asthma and other allergic diseases, and offer novel insights into the pathogenesis of allergic respiratory diseases.

Multi-omics approach to socioeconomic disparity in metabolic syndrome reveals roles of diet and microbiome

The epidemy of metabolic syndrome (MetS) is typically preceded by adoption of a "risky" lifestyle (e.g., dietary habit) among populations. Evidence shows that those with low socioeconomic status (SES) are at an increased risk for MetS. To investigate this, we recruited 123 obese subjects (body mass index [BMI] ≥ 30) from Chicago. Multi-omic data were collected to interrogate fecal microbiota, systemic markers of inflammation and immune activation, plasma metabolites, and plasma glycans. Intestinal permeability was measured using the sugar permeability testing. Our results suggest a heterogenous metabolic dysregulation among obese populations who are at risk of MetS. Systemic inflammation, linked to poor diet, intestinal microbiome dysbiosis, and gut barrier dysfunction may explain the development of MetS in these individuals. Our analysis revealed 37 key features associated with increased numbers of MetS features. These features were used to construct a composite metabolic-inflammatory (MI) score that was able to predict progression of MetS among at-risk individuals. The MI score was correlated with several markers of poor diet quality as well as lower levels of gut microbial diversity and abnormalities in several species of bacteria. This study reveals novel targets to reduce the burden of MetS and suggests access to healthy food options as a practical intervention.

Infant gut microbiota colonization: influence of prenatal and postnatal factors, focusing on diet

Maternal microbiota forms the first infant gut microbial inoculum, and perinatal factors (diet and use of antibiotics during pregnancy) and/or neonatal factors, like intra partum antibiotics, gestational age and mode of delivery, may influence microbial colonization. After birth, when the principal colonization occurs, the microbial diversity increases and converges toward a stable adult-like microbiota by the end of the first 3-5 years of life. However, during the early life, gut microbiota can be disrupted by other postnatal factors like mode of infant feeding, antibiotic usage, and various environmental factors generating a state of dysbiosis. Gut dysbiosis have been reported to increase the risk of necrotizing enterocolitis and some chronic diseases later in life, such as obesity, diabetes, cancer, allergies, and asthma. Therefore, understanding the impact of a correct maternal-to-infant microbial transfer and a good infant early colonization and maturation throughout life would reduce the risk of disease in early and late life. This paper reviews the published evidence on early-life gut microbiota development, as well as the different factors influencing its evolution before, at, and after birth, focusing on diet and nutrition during pregnancy and in the first months of life.

Early Life Exposure to Human Milk Oligosaccharides Reduces Allergic Response in a Murine Asthma Model

Background

Studies suggest that early-life gut microbiota composition and intestinal short-chain fatty acids (SCFAs) are linked to future asthma susceptibility. Furthermore, infancy offers a critical time window to modulate the microbiota and associated metabolites through diet-microbe interactions to promote infant health. Human milk oligosaccharides (HMOs), nondigestible carbohydrates abundant in breast milk, are prebiotics selectively metabolized by gut microbiota that consequently modify microbiome composition and SCFA production.

Methods

Using a house dust mite mouse model of allergy, we investigated the impacts of early oral treatment of pups with biologically relevant doses of 2'-fucosyllactose (2'-FL) and 6'-sialyllactose (6'-SL), two of the most abundant HMOs in human milk, in amelioration of allergic airway disease severity.

Results

We found that administration of 2'-FL and 6'-SL during early life reduced lung histopathology scores, circulating IgE, cytokine levels, and inflammatory cell infiltration, all hallmark symptoms of allergic asthma. HMO supplementation also increased the relative abundance of intestinal Bacteroidetes and Clostridia, known SCFA producers within the gut. Indeed, we detected increased SCFA concentrations in both the intestine and blood of adult mice who received HMOs prior to weaning.

Conclusion

We propose a model in which orally administered HMOs delivered during early life shift the microbiota toward increased production of SCFAs, which dampens the allergic immune responses behind allergy and asthma. Overall, these data suggest the potential for HMO supplementation to protect infants against asthma development later in life, with possible benefits against additional atopic diseases such as eczema and food allergies.

The Footprint of Microbiome in Pediatric Asthma-A Complex Puzzle for a Balanced Development

Considered to be of greater complexity than the human genome itself, the microbiome, the structure of the body made up of trillions of bacteria, viruses, and fungi, has proven to play a crucial role in the context of the development of pathological processes in the body, starting from various infections, autoimmune diseases, atopies, and culminating in its involvement in the development of some forms of cancer, a diagnosis that is considered the most disabling for the patient from a psychological point of view. Therefore, being a cornerstone in the understanding and optimal treatment of a multitude of ailments, the body's microbiome has become an intensively studied subject in the scientific literature of the last decade. This review aims to bring the microbiome-asthma correlation up to date by classifying asthmatic patterns, emphasizing the development patterns of the microbiome starting from the perinatal period and the impact of pulmonary dysbiosis on asthmatic symptoms in children. Likewise, the effects of intestinal dysbiosis reflected at the level of homeostasis of the internal environment through the intestine-lung/vital organs axis, the circumstances in which it occurs, but also the main methods of studying bacterial variability used for diagnostic purposes and in research should not be omitted. In conclusion, we draw current and future therapeutic lines worthy of consideration both in obtaining and maintaining remission, as well as in delaying the development of primary acute episodes and preventing future relapses.

Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk reduce chemokine IL-8 production in response to TNF-α in Caco-2 cell line, an exploratory study

Streptococci are a predominant genera of the human milk microbiome. Among different lactic acid bacteria (LAB) a few Streptococcal strains are also considered as probiotics. Probiotic bacteria are reported to modulate immunity when consumed in adequate amount and bacterial hydrophobicity can be considered as a preliminary experiment for the adhesive capability of probiotic bacteria to the epithelial cells. The present study aimed to investigate the probiotic, hydrophobic and immune modulation property of Streptococcus lactarius MB622 and Streptococcus salivarius MB620, isolated from human milk. S. lactarius MB622 and S. salivarius MB620 displayed higher hydrophobicity (78 % and 59 % respectively) in addition to intrinsic probiotic properties such as gram positive classification, catalase negative activity, resistance to artificially stimulated gastric juice and gastrointestinal bile salt concentration. In conclusion Streptococcus lactarius MB622 and Streptococcus salivarius MB620 isolated from human milk when administered in sufficient amount and for certain duration could be used to reduce inflammation inside the colon by reducing the production of inflammatory booster (IL-8) in diseased state.

Highlights on two decades with microbiota and inflammatory bowel disease from etiology to therapy

Inflammatory Bowel diseases (IBDs) constitute a complex panel of disorders characterized with chronic inflammation affecting the alimentary canal along with extra intestinal manifestations. Its exact etiology is still unknown; however, it seems to be the result of uncharacterized environmental insults in the intestine and their immunological consequences along with dysbiosis, in genetically predisposed individuals. It was the main target of our team since 2002 to explore the etiology of IBD and the related role of bacteria. For almost two decades, our laboratory, among others, has been involved in the reciprocal interaction between the host gastrointestinal lining and the homing microbiota. In the first decade, the attention of scientists focused on the possible role of enteropathogenic E. coli and its relationship to the mechanistic pathways involved in IBD induced in both rats and mice by chemicals like Iodoacetamide, Dextran Sodium Sulfate, Trinitrobenzene, thus linking microbial alteration to IBD pathology. A thorough characterization of the various models was the focus of research in addition to exploring how to establish an active homeostatic composition of the commensal microbiota, including its wide diversity by restoration of gut microbiota by probiotics and moving from dysbiosis to eubiosis. In the last six years and in order to effectively translate such findings into clinical practice, it was critical to explore their relationship to colorectal cancer CRC both in solid tumors and chemically induced CRC. It was also critical to explore the degree of intestinal dysbiosis and linking to IBD, CRC and diabetes. Remarkably, the active mechanistic pathways were proposed as well as the role of microbiota or bacterial metabolites involved. This review covers two decades of investigations in our laboratory and sheds light on the different aspects of the relationship between microbiota and IBD with an emphasis on dysbiosis, probiotics and the multiple mechanistic pathways involved.

Programming Factors of Neonatal Intestinal Dysbiosis as a Cause of Disease

The intestinal microbiota consists of trillions of bacteria, viruses, and fungi that achieve a perfect symbiosis with the host. They perform immunological, metabolic, and endocrine functions in the body. The microbiota is formed intrauterine. Dysbiosis is a microbiome disorder characterized by an imbalance in the composition of the microbiota, as well as changes in their functional and metabolic activities. The causes of dysbiosis include improper nutrition in pregnant women, hormone therapy, the use of drugs, especially antibiotics, and a lack of exposure to the mother’s vaginal microbiota during natural birth. Changes in the intestinal microbiota are increasingly being identified in various diseases, starting in the early neonatal period into the adult period. Conclusions: In recent years, it has become more and more obvious that the components of the intestinal microbiota are crucial for the proper development of the immune system, and its disruption leads to disease.

Breast milk microRNAs: Potential players in oral tolerance development

Breast milk is an essential source of nutrition and hydration for the infant. In addition, this highly complex biological fluid contains numerous immunologically active factors such as microorganisms, immunoglobulins, cytokines and microRNAs (miRNAs). Here, we set out to predict the function of the top 10 expressed miRNAs in human breast milk, focusing on their relevance in oral tolerance development and allergy prevention in the infant. The top expressed miRNAs in human breast milk were identified on basis of previous peer-reviewed studies gathered from a recent systematic review and an updated literature search. The miRNAs with the highest expression levels in each study were used to identify the 10 most common miRNAs or miRNA families across studies and these were selected for subsequent target prediction. The predictions were performed using TargetScan in combination with the Database for Annotation, Visualization and Integrated Discovery. The ten top expressed miRNAs were: let-7-5p family, miR-148a-3p, miR-30-5p family, miR-200a-3p + miR-141-3p, miR-22-3p, miR-181-5p family, miR-146b-5p, miR-378a-3p, miR-29-3p family, miR-200b/c-3p and miR-429-3p. The target prediction identified 3,588 potential target genes and 127 Kyoto Encyclopedia of Genes and Genomes pathways; several connected to the immune system, including TGF-b and T cell receptor signaling and T-helper cell differentiation. This review highlights the role of breast milk miRNAs and their potential contribution to infant immune maturation. Indeed, breast milk miRNAs seem to be involved in several pathways that influence oral tolerance development.

Microbiota dysbiosis and myasthenia gravis: Do all roads lead to Rome?

Dysregulated immune system with a failure to recognize self from non-self-antigens is one of the common pathogeneses seen in autoimmune diseases. The complex interplay of genetic and environmental factors is important for the occurrence and development of the disease. Among the environmental factors, disturbed gut microbiota (gut dysbiosis) has recently attracted particular attention, especially with advancement in human microbiome research. Although the alterations in microbiota have been seen in various autoimmune diseases, including those of nervous system, there is paucity of information on neuromuscular system diseases. Myasthenia gravis (MG) is one such rare autoimmune disease of neuromuscular junction, and is caused by generation of pathogenic autoantibodies to components of the postsynaptic muscle endplate. In the recent years, accumulating evidences have endorsed the key role of host microbiota, particularly those of gut, in the pathogenesis of MG. Differential microbiota composition, characterized by increased abundance of Fusobacteria, Bacteroidetes, and Proteobacteria, and decreased abundance of Actinobacteria and Firmicutes, has been seen in MG patients in comparison to healthy subjects. Disturbance of microbiota composition, particularly reduced ratio of Firmicutes/Bacteroidetes, alter the gut permeability, subsequently triggering the immunological response. Resultant reduction in levels of short chain fatty acids (SCFAs) is another factor contributing to the immunological response in MG patients. Modulation of gut microbiota via intervention of probiotics, prebiotics, synbiotics, postbiotics (metabiotics), and fecal microbiota transplantation (FMT) is considered to be the futuristic approach for the management of MG. This review summarizes the role of gut microbiota and their metabolites (postbiotics) in the progression of MG. Also, various bacteriotherapeutic approaches involving gut microbiota are discussed for the prevention of MG progression.

Breastfeeding enrichment of B. longum subsp. infantis mitigates the effect of antibiotics on the microbiota and childhood asthma risk

BACKGROUND

Early antibiotic exposure is linked to persistent disruption of the infant gut microbiome and subsequent elevated pediatric asthma risk. Breastfeeding acts as a primary modulator of the gut microbiome during early life, but its effect on asthma development has remained unclear.

METHODS

We harnessed the CHILD cohort to interrogate the influence of breastfeeding on antibiotic-associated asthma risk in a subset of children (n = 2,521). We then profiled the infant microbiomes in a subset of these children (n = 1,338) using shotgun metagenomic sequencing and compared human milk oligosaccharide and fatty acid composition from paired maternal human milk samples for 561 of these infants.

FINDINGS

Children who took antibiotics without breastfeeding had 3-fold higher asthma odds, whereas there was no such association in children who received antibiotics while breastfeeding. This benefit was associated with widespread "re-balancing" of taxonomic and functional components of the infant microbiome. Functional changes associated with asthma protection were linked to enriched Bifidobacterium longum subsp. infantis colonization. Network analysis identified a selection of fucosylated human milk oligosaccharides in paired maternal samples that were positively associated with B. infantis and these broader functional changes.

CONCLUSIONS

Our data suggest that breastfeeding and antibiotics have opposing effects on the infant microbiome and that breastfeeding enrichment of B. infantis is associated with reduced antibiotic-associated asthma risk.

FUNDING

This work was supported in part by the Canadian Institutes of Health Research; the Allergy, Genes and Environment Network of Centres of Excellence; Genome Canada; and Genome British Columbia.

Effects of breast milk on Behçet's disease clinical features

BACKGROUND

The etiology of Behçet's disease (BD) is not clearly known, however, abnormal activity in T helper (Th) 1, Th 17, and regulatory T cells (Treg) has critical importance in pathogenesis. It has been shown that the intestinal microbiome can be effective in the modulation of these immune abnormalities in BD patients. Breastfeeding increases the maturation of the infant's intestinal permeability by affecting the newborn's immature intestinal microbiome and metagenome. We aimed to examine the effects of breastfeeding on disease related symptoms, organ involvements and course of the disease in BD patients.

METHODS

This study was designed as a cross-sectional study in Ankara City Hospital rheumatology clinic between December 2021 and March 2022. Patients who were diagnosed with BD by meeting the criteria of the 'International Study Group' and whose information we could access by agreeing to participate in the study were enrolled. The mothers of the patients were also contacted and asked whether these patients were breastfed, the duration of breastfeeding, and the mode of birth. Demographic and clinical data of the patients, comorbid diseases, and drugs used for BD were collected from the records in the hospital database. The presence of sacroiliitis in patients was evaluated with sacroiliac X-ray and/or magnetic resonance imaging (MRI), which was requested because of low back pain symptoms and only patients with previous sacroiliac imaging for low back pain were included in the study. BD-related organ damage was measured by the Vasculitis Damage Index (VDI) and Behçet's syndrome Overall Damage Index (BODI) scores.

RESULTS

: A total of 304 patients were included in the study. The percentage of patients who were reported to have ever breastfed (median duration (IQR): 12(12) months, 33.5% < 6 months, 66.4% ≥ 6 months, and 59.6% ≥ 12 months) is 92%. When the breastfed and nonbreastfed patients were compared, 6.8% of the breastfed patients needed TNF-i against 18.2% of the nonbreastfed patients (p = 0.052). While the rate of having at least one comorbidity was 26.4% for those who were breastfed, this rate was 50% for those who had never been breastfed. When the organ and system involvements of the patients were compared, the incidence of sacroiliitis was statistically significantly higher in the nonbreastfed group (p = 0.025). Patients who were breastfed for less than 6 months were diagnosed with BD at an earlier age than those who were breastfed for more than 6 months, and those who were breastfed for less than 12 months compared to those who were breastfed for more than 12 months (respectively, p = 0.039, p = 0.035).

DISCUSSION

Our results imply that history of breastfeeding may have some positive effects on the course of the disease in BD patients.

Specific Human Milk Oligosaccharides Differentially Promote Th1 and Regulatory Responses in a CpG-Activated Epithelial/Immune Cell Coculture

Proper early life immune development creates a basis for a healthy and resilient immune system, which balances immune tolerance and activation. Deviations in neonatal immune maturation can have life-long effects, such as development of allergic diseases. Evidence suggests that human milk oligosaccharides (HMOS) possess immunomodulatory properties essential for neonatal immune maturation. To understand the immunomodulatory properties of enzymatic or bacterial produced HMOS, the effects of five HMOS (2'FL, 3FL, 3'SL, 6'SL and LNnT), present in human milk have been studied. A PBMC immune model, the IEC barrier model and IEC/PBMC transwell coculture models were used, representing critical steps in mucosal immune development. HMOS were applied to IEC cocultured with activated PBMC. In the presence of CpG, 2'FL and 3FL enhanced IFNγ (p < 0.01), IL10 (p < 0.0001) and galectin-9 (p < 0.001) secretion when added to IEC; 2'FL and 3FL decreased Th2 cell development while 3FL enhanced Treg polarization (p < 0.05). IEC were required for this 3FL mediated Treg polarization, which was not explained by epithelial-derived galectin-9, TGFβ nor retinoic acid secretion. The most pronounced immunomodulatory effects, linking to enhanced type 1 and regulatory mediator secretion, were observed for 2'FL and 3FL. Future studies are needed to further understand the complex interplay between HMO and early life mucosal immune development.

Stability of Human-Milk Oligosaccharide Concentrations Over 1 Week of Lactation and Over 6 Hours Following a Standard Meal

BACKGROUND

Our previous studies revealed that human-milk oligosaccharides (HMOs) have health benefits for nursing infants and their concentrations change dynamically over 24 mo of lactation. Yet, the extent to which HMOs vary over the short term (days) and in response to acute factors such as maternal diet is unclear.

OBJECTIVE

The purpose of this study was to determine the stability of HMO concentrations over 7 d and in response to a standard meal and sugar-sweetened beverage (SSB) over 6 h.

METHODS

In this ancillary study, lactating mothers were enrolled at 6 wk postpartum. Participants received in-person instructions and materials to complete procedures at home. In the 1-wk experiment (n = 11), mothers pumped a milk sample at 07:00 h for 7 consecutive days. In the 6-h experiment (n = 35), mothers pumped a milk sample after an overnight fast at 06:00 h and then consumed a standard meal plus SSB provided by the study team. Mothers pumped a milk sample every hour for 6 consecutive hours. Samples were analyzed for the 19 most abundant HMOs. Repeated-measures ANOVA was used to test changes in HMO concentrations over time, reported as F(dftime, dferror) = F value, P value.

RESULTS

Concentrations of all assayed HMOs were stable over 7 consecutive days, including, for example, the most widely studied HMOs in relation to infant health: 2'-fucosyllactose (2'FL) [F(2,17) = 0.39, P = 0.65], disialyl-lacto-N-tetraose (DSLNT) [F(4, 37) = 0.60, P = 0.66], and lacto-N-neotetraose (LNnT) [F(3, 32) = 1.5, P = 0.23]. Concentrations of all assayed HMOs were stable in response to a standard meal plus SSB. For example, fasted baseline concentrations of 2'FL, DSLNT, and LNnT were 2310 ± 1620 μg/mL, 560 ± 290 μg/mL, and 630 ± 290 μg/mL, respectively, and there were no changes in 2'FL [F(4, 119) = 1.9, P = 0.13], DSLNT [F(4, 136) = 0.39, P = 0.83], and LNnT [F(4, 120) = 0.64, P = 0.63] over 6 consecutive hours.

CONCLUSIONS

HMO concentrations are stable over 1 wk of lactation and are not acutely affected by a standard meal plus SSB in mothers.

Human milk oligosaccharides as prebiotics

Based on its richness in immune-related components such as human milk, human milk oligosaccharides (HMOs), milk proteins, and lipids, breast milk can be considered the first functional food that humans encounter in their lifetime. According to WHO recommendations breast milk has to be the only food in an infant's diet in the first six months of age which is then continued up to two years of age with the suitable complementary foods. Regarding breast milk balanced composition, it is considered as the best food of infants thus many studies have been carried out to determine the benefits of breast milk. Based on numerous studies breast milk have a tendency to reduce the risk of type 2 diabetes, obesity, allergies, celiac disease, necrotizing enterocolitis (NEC), gastrointestinal tract infections and some type of cancers. The benefits of breast milk can be explained by its special combination which includes; macronutrients, micronutrients and bioactive components such as immunoglobulins, hormones, growth factors and oligosaccharides. One of the essential bioactive compounds of breast milk is known as human milk oligosaccharides (HMOs). HMOs are unique, bioactive carbohydrates which are identified as the most significant components of breast milk. Since they have structural complexity and multifunctional properties, they are one of the most wondered components of breast milk. HMOs promote the development of the neonatal intestinal immune, and nervous systems. This article briefly describes the history, complex structure and different functions of HMOs and highlight the importance of maternal diet for HMO biosynthesis.

Accumulation of Black Carbon Particles in Placenta, Cord Blood, and Childhood Urine in Association with the Intestinal Microbiome Diversity and Composition in Four- to Six-Year-Old Children in the ENVIRONAGE Birth Cohort

BACKGROUND

The gut microbiome plays an essential role in human health. Despite the link between air pollution exposure and various diseases, its association with the gut microbiome during susceptible life periods remains scarce.

OBJECTIVES

In this study, we examined the association between black carbon particles quantified in prenatal and postnatal biological matrices and bacterial richness and diversity measures, and bacterial families.

METHODS

A total of 85 stool samples were collected from 4- to 6-y-old children enrolled in the ENVIRonmental influence ON early AGEing birth cohort. We performed 16S rRNA gene sequencing to calculate bacterial richness and diversity indices (Chao1 richness, Shannon diversity, and Simpson diversity) and the relative abundance of bacterial families. Black carbon particles were quantified via white light generation under femtosecond pulsed laser illumination in placental tissue and cord blood, employed as prenatal exposure biomarkers, and in urine, used as a post-natal exposure biomarker. We used robust multivariable-adjusted linear models to examine the associations between quantified black carbon loads and measures of richness (Chao1 index) and diversity (Shannon and Simpson indices), adjusting for parity, season of delivery, sequencing batch, age, sex, weight and height of the child, and maternal education. Additionally, we performed a differential relative abundance analysis of bacterial families with a correction for sampling fraction bias. Results are expressed as percentage difference for a doubling in black carbon loads with 95% confidence interval (CI).

RESULTS

Two diversity indices were negatively associated with placental black carbon [Shannon: -4.38% (95% CI: -8.31%, -0.28%); Simpson: -0.90% (95% CI: -1.76%, -0.04%)], cord blood black carbon [Shannon: -3.38% (95% CI: -5.66%, -0.84%); Simpson: -0.91 (95% CI: -1.66%, -0.16%)], and urinary black carbon [Shannon: -3.39% (95% CI: -5.77%, -0.94%); Simpson: -0.89% (95% CI: -1.37%, -0.40%)]. The explained variance of black carbon on the above indices varied from 6.1% to 16.6%. No statistically significant associations were found between black carbon load and the Chao1 richness index. After multiple testing correction, placental black carbon was negatively associated with relative abundance of the bacterial families Defluviitaleaceae and Marinifilaceae, and urinary black carbon with Christensenellaceae and Coriobacteriaceae; associations with cord blood black carbon were not statistically significant after correction.

CONCLUSION

Black carbon particles quantified in prenatal and postnatal biological matrices were associated with the composition and diversity of the childhood intestinal microbiome. These findings address the influential role of exposure to air pollution during pregnancy and early life in human health. https://doi.org/10.1289/EHP11257.

Assessing the Use of Host-Guest Chemistry in Conjunction with Cyclic Ion Mobility Separations for the Linkage-Specific Characterization of Human Milk Oligosaccharides

Human milk oligosaccharides (HMOs) are a class of glycans that are highly abundant in human milk and contribute to the healthy growth of an infant's immune system. While new advancements in analytical methodologies have been made in glycomics, the high degree of isomeric heterogeneity and lack of authentic standards have made the high-resolution separation and accurate characterization of linkage positioning of all HMO species very challenging. Herein, we present an evaluation of the use of host-guest chemistry in conjunction with cyclic ion mobility spectrometry-mass spectrometry (cIMS-MS)-based separations for the identification of linkage positioning in three pairs of di-, tetra-, and hexasaccharide HMO isomers that only differ in the positioning of one glycosidic linkage (β1,3 versus β1,4). Suitable hosts, such as α/β cyclodextrins, cucurbit[n]urils (n = 5, 7), crown ethers, cyclic peptides, and an ionophore, were used to assess host-guest inclusion complex formation as well as linkage-specific cIMS-MS trends. Our results indicated a linkage-specific trend for the [M + 2α + 2H]2+ cyclodextrin-based host-guest inclusion complexes where the β1,3 linkage-containing isomers were always higher mobility than the β1,4 linkage-containing ones as well one for the [M + α + β + 2H]2+ complexes where the β1,4 linkage-containing isomers were always higher mobility than the β1,3 linkage-containing ones. We also observed diagnostic mobility fingerprints for the cucurbituril-based complexes. We anticipate that linkage-specific and mobility fingerprint trends can potentially aid in identifying linkage positioning for other HMO isomers as well as in complex human milk samples.

Biotics in neonatal period: what's the evidence?

Breastfeeding is considered the gold standard for infants' nutrition and provides unique benefits for infants' health. Great research interest has been raised about the use of bioactive components in neonatal medicine, both as standalone products and as addition to infant formula, in the attempt to reproduce human milk beneficial effects. Thus, the aim of this narrative review is to summarize most recent evidence on biotics' use in the neonatal period, with a focus on infant formula (IF) supplemented with probiotics, prebiotics, synbiotics and postbiotics. Growing data indicate overall positive effects of biotic supplemented formula on microbiome composition and metabolic activity. Furthermore, some benefits are also emerging from randomized controlled trials evaluating the clinical impact these enriched formulas may have on the health of formula fed infants. However, clear evidence still lacks and none of this supplemented IF has demonstrated conclusive superiority. To date, whereas no routine recommendations can be done, biotics supplemented IF have generally proven to be well-tolerated and safe in ensuring infants' normal growth, paving the way for future IF alternatives for those infants who are not able to be (fully) breastfed. More RCTs, with adequate design and statistical power, are still needed to better clarify, if present, which benefits the supplementation of IF may confer to infants' short and long-term outcomes.

The development of the gut microbiome and temperament during infancy and early childhood: A systematic review

Temperament in early childhood is a good predictor of later personality, behavior, and risk of psychopathology. Variation in temperament can be explained by environmental and biological factors. One biological mechanism of interest is the gut microbiome (GM), which has been associated with mental and physical health. This review synthesized existing literature evaluating the relationship between GM composition and diversity, and temperament in early life. Web of Science, PsycInfo, PubMed, and Scopus were searched, and data were extracted according to PRISMA guidelines. In total, 1562 studies were identified, of which six remained following application of exclusion/inclusion criteria. The findings suggest that there is an association between higher alpha diversity and temperament: greater Surgency/Extraversion and High-Intensity Pleasure in males, and lower Effortful Control in females. Unique community structures (beta diversity) were found for Surgency/Extraversion in males and Fear in females. An emerging pattern of positive temperament traits being associated with GM communities biased toward short-chain fatty acid production from a metabolism based on dietary fiber and complex carbohydrates was observed and is worthy of further investigation. To gain deeper understanding of the relationship, future research should investigate further the functional aspects of the microbiome and the influence of diet.

Association of Exclusive Breastfeeding with Asthma Risk among Preschool Children: An Analysis of National Health and Nutrition Examination Survey Data, 1999 to 2014

Breastmilk contains many important nutrients, anti-inflammatory agents, and immunomodulators. It is the preferred nutrition source for infants. However, the association of the duration of exclusive breastmilk feeding (BMF) with asthma development is unclear. Data on children from the United States who participated in the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2014 were obtained. We examined the association between the duration of exclusive BMF and asthma in 6000 children (3 to 6 years old). After calculating the duration of exclusive breastfeeding according to answers to NHANES questionnaires, the estimated duration of exclusive BMF was divided into five categories: never breastfed or BMF for 0 to 2 months after birth; BMF for 2 to 4 months after birth; BMF for 4 to 6 months after birth; and BMF for ≥6 months after birth. The overall prevalence of asthma in children aged 3 to 6 years was approximately 13.9%. The risk of asthma was lower in children with an exclusive BMF duration of 4 to 6 months (aOR, 0.69; 95% CI, 0.48–0.98), after adjustment for potentially confounding factors. Subgroup analysis revealed that children of younger ages (3 to 4 years old) benefited most from the protective effects of exclusive BMF for 4 to 6 months (aOR, 0.47; 95% CI, 0.27, 0.8). We found that exclusive BMF, especially BMF for 4 to 6 months, is associated with a decreased risk of asthma in preschool-age children. The protective effect appeared to be diminished in older children. The potential mechanism needs further investigation.

Microbiome-Immune Interactions in Allergy and Asthma

The human microbiota has been established as a key regulator of host health, in large part owing to its constant interaction with and impact on host immunity. A range of environmental exposures spanning from the prenatal period through adulthood are known to affect the composition and molecular productivity of microbiomes across mucosal and dermal tissues with short- and long-term consequences for host immune function. Here we review recent findings in the field that provide insights into how microbial-immune interactions promote and sustain immune dysfunction associated with allergy and asthma. We consider both early life microbiome perturbation and the molecular underpinnings of immune dysfunction associated with subsequent allergy and asthma development in childhood, as well as microbiome features that relate to phenotypic attributes of allergy and asthma in older patients with established disease.

Current Use of Probiotics and Prebiotics in Allergy

The microbiome plays an important role in the pathogenesis of allergic diseases. This review updates the reader on studies aimed at influencing allergic diseases through modulation of the gut microflora. A nonsystematic review of the literature was performed, focusing on relevant trials evaluating the effect of probiotics/prebiotics/symbiotics in the prevention and treatment of allergic disease. For each allergic disease, we were able to find not only a substantial number of clinical trials but also systematic reviews. Specific guidelines, based on systematic reviews and meta-analyses, are available for the prevention of allergic disease and for the treatment of food allergy. In each of the areas examined-allergic rhinitis, allergic asthma, atopic dermatitis, food allergy, and gastrointestinal allergies-there are substantial uncertainties in the efficacy of gut microflora modulation in prevention and treatment. At present, practicing clinicians can avail themselves of intestinal flora modulators as an adjunct in the prevention of atopic dermatitis but not of other forms of allergic diseases. Their effects on the treatment of allergic diseases remain controversial.

Biomolecular Mechanisms of Autoimmune Diseases and Their Relationship with the Resident Microbiota: Friend or Foe?

The use of innovative approaches to elucidate the pathophysiological mechanisms of autoimmune diseases, as well as to further study of the factors which can have either a positive or negative effect on the course of the disease, is essential. In this line, the development of new molecular techniques and the creation of the Human Genome Program have allowed access to many more solutions to the difficulties that exist in the identification and characterization of the microbiome, as well as changes due to various factors. Such innovative technologies can rekindle older hypotheses, such as molecular mimicry, allowing us to move from hypothesis to theory and from correlation to causality, particularly regarding autoimmune diseases and dysbiosis of the microbiota. For example, Prevotella copri appears to have a strong association with rheumatoid arthritis; it is expected that this will be confirmed by several scientists, which, in turn, will make it possible to identify other mechanisms that may contribute to the pathophysiology of the disease. This article seeks to identify new clues regarding similar correlations between autoimmune activity and the human microbiota, particularly in relation to qualitative and quantitative microbial variations therein.

Fecal microbiota transplantation in the metabolic diseases: Current status and perspectives

With the development of microbiology and metabolomics, the relationship between the intestinal microbiome and intestinal diseases has been revealed. Fecal microbiota transplantation (FMT), as a new treatment method, can affect the course of many chronic diseases such as metabolic syndrome, malignant tumor, autoimmune disease and nervous system disease. Although the mechanism of action of FMT is now well understood, there is some controversy in metabolic diseases, so its clinical application may be limited. Microflora transplantation is recommended by clinical medical guidelines and consensus for the treatment of recurrent or refractory Clostridium difficile infection, and has been gradually promoted for the treatment of other intestinal and extraintestinal diseases. However, the initial results are varied, suggesting that the heterogeneity of the donor stools may affect the efficacy of FMT. The success of FMT depends on the microbial diversity and composition of donor feces. Therefore, clinical trials may fail due to the selection of ineffective donors, and not to faulty indication selection for FMT. A new understanding is that FMT not only improves insulin sensitivity, but may also alter the natural course of type 1 diabetes by modulating autoimmunity. In this review, we focus on the main mechanisms and deficiencies of FMT, and explore the optimal design of FMT research, especially in the field of cardiometabolic diseases.

Intergenerational Transfer of Persistent Bacterial Communities in Female Nile Tilapia

Resident microbial communities that can support various host functions play a key role in their development and health. In fishes, microbial symbionts are vertically transferred from the parents to their progeny. Such transfer of microbes in mouthbrooder fish species has not been reported yet. Here, we employed Nile tilapia (Oreochromis niloticus) to investigate the vertical transmission of microbes across generations using a 16S rRNA amplicon sequencing approach, based on the presence of bacteria in different generations. Our analysis revealed that the core microbiome in the buccal cavity and posterior intestine of parents shapes the gut microbiome of the progeny across generations. We speculate that the route of this transmission is via the buccal cavity. The identified core microbiome bacteria, namely Nocardioides, Propionibacterium, and Sphingomonas have been reported to play an essential role in the health and development of offspring. These core microbiome members could have specific functions in fish, similar to mammals.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

Secretory IgA: Linking microbes, maternal health, and infant health through human milk

Secretory immunoglobulin A (SIgA) in human milk plays a central role in complex maternal-infant interactions that influence long-term health outcomes. Governed by genetics and maternal microbial exposure, human milk SIgA shapes both the microbiota and immune system of infants. Historically, SIgA-microbe interactions have been challenging to unravel due to their dynamic and personalized nature, particularly during early life. Recent advances have helped to clarify how SIgA acts beyond simple pathogen clearance to help guide and constrain a healthy microbiota, promote tolerance, and influence immune system development. In this review, we highlight these new findings in the context of the critical early-life window and propose outstanding areas of study that will be key to harnessing the benefits of SIgA to support healthy immune development during infancy.

Timing of antimicrobial prophylaxis for cesarean section is critical for gut microbiome development in term born infants

Animal models imply that the perinatal exposure to antibiotics has a substantial impact on microbiome establishment of the offspring. We aimed to evaluate the effect of timing of antimicrobial prophylaxis for cesarean section before versus after cord clamping on gut microbiome composition of term born infants. We performed an exploratory, single center randomized controlled clinical trial. We included forty pregnant women with elective cesarean section at term. The intervention group received single dose intravenous cefuroxime after cord clamping (n = 19), the control group single dose intravenous cefuroxime 30 minutes before skin incision (n = 21). The primary endpoint was microbiome signature of infants and metabolic prediction in the first days of life as determined in meconium samples by 16S rRNA gene sequencing. Secondary endpoints were microbiome composition at one month and 1 year of life. In meconium samples of the intervention group, the genus Staphylococcus pre-dominated. In the control group, the placental cross-over of cefuroxime was confirmed in cord blood. A higher amino acid and nitrogen metabolism as well as increased abundance of the genera Cutibacterium, Corynebacterium and Streptophyta were noted (indicator families: Cytophagaceae, Lactobacilaceae, Oxalobacteraceae). Predictive models of metabolic function revealed higher 2'fucosyllactose utilization in control group samples. In the follow-up visits, a higher abundance of the genus Clostridium was evident in the intervention group. Our exploratory randomized controlled trial suggests that timing of antimicrobial prophylaxis is critical for early microbiome engraftment but not antimicrobial resistance emergence in term born infants.

Association Between Breastmilk Microbiota and Food Allergy in Infants

Regulating the composition of human breastmilk has the potential to prevent allergic diseases early in life. The composition of breastmilk is complex, comprising varying levels of oligosaccharides, immunoactive molecules, vitamins, metabolites, and microbes. Although several studies have examined the relationship between different components of breastmilk and infant food allergies, few have investigated the relationship between microorganisms in breastmilk and infant food allergy. In the present study, we selected 135 healthy pregnant women and their full-term newborns from a cohort of 202 mother-infant pairs. Among them, 69 infants were exclusively breastfed until 6 mo after birth. At follow-up, 11 of the 69 infants developed a food allergy in infancy while 22 showed no signs of allergy. Thirty-three breastmilk samples were collected within 1 mo after delivery, and 123 infant fecal samples were collected at five time points following their birth. These samples were analyzed using microbial 16S rRNA gene sequencing. The abundance and evenness of the milk microbiota and the number of differential bacteria were higher in the breastmilk samples from the non-allergy group than in those from the food allergy group. The non-allergy group showed relatively high abundance of Bifidobacterium, Akkermansia, Clostridium IV, Clostridium XIVa, Veillonella, and butyrate-producing bacteria such as Fusobacterium, Lachnospiraceae incertae sedis, Roseburia, and Ruminococcus. In contrast, the abundance of Proteobacteria, Acinetobacter, and Pseudomonas in breastmilk was higher in the food allergy group. A comparison of the changes in dominant differential breastmilk microbiota in the intestinal flora of the two groups of infants over time revealed that the changes in Bifidobacterium abundance were consistent with those in the breastmilk flora. Functional pathway prediction of breastmilk microflora showed that the enhancement of the metabolic pathways of tyrosine, tryptophan, and fatty acids was significantly different between the groups. We suggest that changes in the breastmilk microbiota can influence the development of food allergies. Breastmilk contains several microbes that have protective effects against food allergies, both by influencing the colonization of intestinal microbiota and by producing butyrate. This study may provide new ideas for improving infant health through early intervention with probiotics.

Probiotic supplementation in healthy pre-school-aged children: Prevalence and predictors

AIM

Probiotics have been shown to prevent or treat a number of paediatric health problems; however, not much is known about how probiotics are used in the community. This study aimed to describe the prevalence and main predictors of probiotic supplementation among healthy pre-school-aged children.

METHODS

Parents of 4- or 5-year-olds residing in the Australian Capital Territory (ACT) were invited to complete a web-based questionnaire between February and May 2020. There were 469 responses concerning 494 children eligible for analysis. Prevalence was categorised as lifetime exposure and recent exposure. Predictors were determined through multiple logistic regression modelling.

RESULTS

Almost half (47.4%) of the children had ever been exposed to probiotics and 14.9% had taken probiotics in the previous month. The strongest predictors of lifetime probiotic exposure were parental lifetime probiotic use (OR 13.3; 95% CI 7.4-24.1) and an interaction between functional food consumption and parental lifetime probiotic use (OR 5.6; 95% CI 2.6-12.1). The strongest predictor of recent probiotic exposure was parental recent probiotic use (OR 13.3; 95% CI 5.7-30.8).

CONCLUSIONS

This study illustrates the high prevalence of probiotic exposure among healthy pre-school-aged children in the ACT and emphasises the relationship between parental use of probiotics and exposure in children. These findings will allow comparison and analysis of trends over time. Practitioners should be aware of the evidence for and against probiotics as these findings suggest a high level of acceptability among parents.

Gut Microbiota and Immune Modulatory Properties of Human Breast Milk Streptococcus salivarius and S. parasanguinis Strains

Human breast milk Streptococcus spp. are transferred to infant guts via breast feeding, but their effects on the gut microbiota and immunity remain unclear. In this study, we characterized gut microbiota and immune modulatory properties of human breast milk S. salivarius F286 and S. parasanguinis F278 that had been shown to be able to colonize gut. The two Streptococcus strains were orally administered to mouse pups individually at 1 × 10⁷ cells/day from postnatal Days 1 to 21. At postnatal week 3 (the weaning period), S. salivarius F286 reduced the colonic microbiota α-diversity, increased 21 amplicon sequence variants (ASVs), including bacteria from Akkermansia, Intestinimonas, and Lachnospiraceae, and decreased 52 ASVs, including bacteria from Eubacterium, Bifidobacterium, Escherichia-Shigella, and Turicibacter; however, S. parasanguinis F278 didn't change the colonic microbiota. Both Streptococcus strains reduced the ileal mRNA expression of cytokine/transcription factor representatives of T helper (Th) cells, including IFN-γ (Th1), Gata3 (Th2), and TGF-β (Treg) in 2-week-old suckling mice, and promoted the ileal expression of Foxp3 and TGF-β, which are representatives of anti-inflammatory Treg cells, in 3-week-old weaning mice. The two Streptococcus strains exhibited anti-inflammatory potential when incubated in vitro with human peripheral blood mononuclear cells and TNF-α-treated gut epithelial HT29 cells. In C. elegans, both strains activated immune response genes, which was associated with their lifespan-prolonging effects. Our results suggest that S. salivarius F286 and S. parasanguinis F278 may exert regulatory (anti-inflammatory) roles in gut immunity and S. salivarius F286 can modulate gut microbiota, and highlight the probiotic potential of milk S. salivarius and S. parasanguinis strains.

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.

Maternal Influences and Intervention Strategies on the Development of Food Allergy in Offspring

Food allergies and other immune-mediated diseases have become serious health concerns amongst infants and children in developed and developing countries. The absence of available cures limits disease management to allergen avoidance and symptomatic treatments. Research has suggested that the presence of maternal food allergies may expose the offspring to genetic predisposition, making them more susceptible to allergen sensitization. The following review has focused on epidemiologic studies regarding maternal influences of proneness to develop food allergy in offspring. The search strategy was "food allergy OR maternal effects OR offspring OR prevention". A systematically search from PubMed/MEDLINE, Science Direct and Google Scholar was conducted. Specifically, it discussed the effects of maternal immunity, microbiota, breastfeeding, genotype and allergy exposure on the development of food allergy in offspring. In addition, several commonly utilized prenatal and postpartum strategies to reduce food allergy proneness were presented, including early diagnosis of high-risk infants and various dietary interventions.

Chrononutrition and Human Milk

Background

Breastfed infants have a reduced risk of infections and allergies. The study of chrononutrition in human milk seeks to understand the circadian variation of various human milk immune factors.

Methods

Empirical studies on human milk, chrononutrition, and immune factors were searched through PUBMED, Google Scholar, and SCOPUS. Keywords included “chrononutrition,” “breastmilk composition,” “human milk,” “day-night cycles,” “sleep-wake cycles” and the names of various immune factors. After excluding duplicate articles, animal studies, studies looking at other human milk components, studies that did not collect human milk samples over a 24 hour period, and studies that were not in English, eleven studies on the topic remained and ten studies were included in the review. The excluded study had a sample size of two.

Results

This review identified the circadian variation of certain immune factors found in human milk such as antibodies, complement proteins, cytokines, by-products of phagocyte activity, nucleotides, microRNAs, and antioxidants.

Conclusion

The circadian variation observed in some human milk components highlights the unique ability of human milk to vary in composition based on the circadian rhythms of mothers and infants. The limited number of studies makes it difficult to make conclusive recommendations and creates an opportunity for further research in this growing field.

OUP accepted manuscript

The intestinal microbiota plays a crucial role in health and changes in its composition are linked with major global human diseases. Fully understanding what shapes the human intestinal microbiota composition and knowing ways of modulating the composition are critical for promotion of life-course health, combating diseases, and reducing global health disparities. We aim to provide a foundation for understanding what shapes the human intestinal microbiota on an individual and global scale, and how interventions could utilize this information to promote life-course health and reduce global health disparities. We briefly review experiences within the first 1,000 days of life and how long-term exposures to environmental elements or geographic specific cultures have lasting impacts on the intestinal microbiota. We also discuss major public health threats linked to the intestinal microbiota, including antimicrobial resistance and disappearing microbial diversity due to globalization. In order to promote global health, we argue that the interplay of the larger ecosystem with intestinal microbiota research should be utilized for future research and urge for global efforts to conserve microbial diversity.

The Association of Breastfeeding With Childhood Asthma: A Case-Control Study From India

Background

The role of breastfeeding in childhood asthma has long been controversial. The majority of research pertains to developed countries with scant literature available in a developing country like India, where a different asthma phenotype is prevalent. This study examined the association of breastfeeding duration and exclusiveness with childhood asthma and its severity, as measured by peak expiratory flow rate (PEFR) in India.

Methodology

We conducted a matched case-control study in Pune, India. A total of 180 children with asthma (cases) and 180 without the disease (controls) were included. A standardized questionnaire recorded demographics and medical and breastfeeding history. PEFR readings were obtained from each child. Conditional logistic regression and linear regression were used to explore the association of breastfeeding with asthma and PEFR, respectively.

Results

The median duration of breastfeeding among cases was [5 (2.5-10)] months as compared to controls [9 (3.5-16.8)] months. The prevalence of exclusive breastfeeding among mothers was 60% (50% among cases and 69% among controls). Exclusive breastfeeding was associated with a 46% lower likelihood of having asthma with a probability (p-value) of 0.025 where the odds ratio (OR) was 1.85, with a 95% confidence interval (CI) of 1.08 to 3.16. Breastfeeding duration was significantly associated with a lower likelihood of having asthma (p = 0.001) (OR 0.87; 95% CI 0.79-0.94). One-month increase in the duration of breastfeeding was associated with a 23% reduced risk of the disease. The odds of maternal asthma [21.4 (4.22-109.36)], paternal smoking [1.44 (0.22-0.86)], and maternal smoking [5.14 (1.78-14.80)] were higher among children with asthma as compared to children without asthma. The weight of the child and duration of breastfeeding were negatively associated with PEFR. Maternal asthmatic history, associated allergies, paternal smoking, and parents’ education were positively associated with PEFR for the overall sample.

Conclusion

Prolonged and exclusive breastfeeding was found to be a protective factor against the development of asthma. Promotion of breastfeeding and smoking cessation should be a priority in the control of childhood asthma. Further research should be conducted to explore the negative correlation between duration and frequency of breastfeeding and PEFR.