Newborn Intestine Research Articles

Human milk extracellular vesicles modulate inflammation and cell survival in intestinal and immune cells.

Human milk contains extracellular vesicles (EVs) that carry bioactive molecules such as microRNA, to the newborn intestine. The downstream effects of EV cargo on signaling and immune modulation may shield neonates against inflammatory diseases, including necrotizing enterocolitis. Premature infants are especially at risk, while human milk-feeding may offer protection. The effect of gestational-age specific term and preterm EVs from transitional human milk was characterized on human intestinal epithelial cells (HIECs and Caco-2), primary macrophages, and THP-1 monocytes. We hypothesized that term and preterm EVs differentially influence immune-related cytokines and cell death. We found that preterm EVs were enriched in CD14 surface marker, while both term and preterm EVs increased epidermal growth factor secretion. Following inflammatory stimuli, only term EVs inhibited secretion of IL-6 in HIECs, and reduced expression of pro-inflammatory cytokine IL-1β in macrophages. Term and preterm EVs inhibited secretion of IL-1β and reduced inflammasome related cell death. We proposed that human milk EVs regulate immune-related signaling via their conserved microRNA cargo, which could promote tolerance and a homeostatic immune response. These findings provide basis for further studies into potential therapeutic supplementation with EVs in vulnerable newborn populations by considering functional, gestational age-specific effects. IMPACT: This study reveals distinct functional differences between term and preterm transitional human milk extracellular vesicles (EVs) highlighting the importance of gestational age in their bioactivity. Term EVs uniquely inhibited IL-6 secretion, IL-1β expression, and apoptosis following inflammatory stimuli. Both term and preterm human milk EVs reduced IL-1β secretion and inflammasome-induced cell death. Conserved human milk extracellular vesicle microRNA cargo could be a mediator of the anti-inflammatory effects, particularly targeting cytokine production, the inflammasome, and programmed cell death. These findings underscore the importance of considering gestational age in future research exploring the therapeutic potential of human milk extracellular vesicles to prevent or treat intestinal inflammatory diseases in neonates.

Intrauterine Shaping of Fetal Microbiota.

Mechanisms resulting from the physiological immaturity of the digestive system in children delivered before 32 weeks of gestation and, in particular, different interactions between the microbiome and the body have not been fully elucidated yet. Next-generation sequencing methods demonstrated the presence of bacterial DNA in the placenta and amniotic fluid, which may reflect bacterial populations that initiate intestinal colonization in utero. Numerous studies confirmed the hypothesis stating that intestinal bacteria played an important role in the pathogenesis of necrotizing enterocolitis (NEC) early- and late-onset neonatal sepsis (EONS and LONS). The model and scale of disorders within the intestinal microbiome are the subject of active research in premature infants. Neonatal meconium was primarily used as an indicator defining the environment in utero, as it is formed before birth. Metagenomic results and previous data from microbiological bacterial cultures showed a correlation between the time from birth to sample collection and the detection of bacteria in the neonatal meconium. Therefore, it may be determined that the colonization of the newborn's intestines is influenced by numerous factors, which may be divided into prenatal, perinatal, and postnatal, with particular emphasis put on the mode of delivery and contact with the parent immediately after birth. Background: The aim of this review was to collect available data on the intrauterine shaping of the fetal microbiota. Methods: On 13 March 2024, the available literature in the PubMed National Library of Medicine search engine was reviewed using the following selected keywords: "placental microbiome", "intestinal bacteria in newborns and premature infants", and "intrauterine microbiota". Results: After reviewing the available articles and abstracts and an in-depth analysis of their content, over 100 articles were selected for detailed elaboration. We focused on the origin of microorganisms shaping the microbiota of newborns. We also described the types of bacteria that made up the intrauterine microbiota and the intestinal microbiota of newborns. Conclusions: The data presented in the review on the microbiome of both term newborns and those with a body weight below 1200 g indicate a possible intrauterine colonization of the fetus depending on the duration of pregnancy. The colonization occurs both via the vaginal and intestinal route (hematogenous route). However, there are differences in the demonstrated representatives of various types of bacteria, phyla Firmicutes and Actinobacteria in particular, taking account of the distribution in their abundance in the individual groups of pregnancy duration. Simultaneously, the distribution of the phyla Actinobacteria and Proteobacteria is consistent. Considering the duration of pregnancy, it may also be concluded that the bacterial flora of vaginal origin dominates in preterm newborns, while the flora of intestinal origin dominates in term newborns. This might explain the role of bacterial and infectious factors in inducing premature birth with the rupture of fetal membranes.

Breast milk microbiota of healthy women living in the Russian Federation

Introduction. Mother’s breast milk is considered to be the best source of infant nutrition and, paradoxical as it may sound, the only product of the infant diet, which composition is still poorly known to us. This article presents the findings of a study on the breast milk microbiota conducted in the Russian Federation for the first time.Aim. To study the composition of the breast milk microbiota of healthy women living in the Russian Federation and identify the impact of various factors on its diversity.Materials and methods. A molecular genetic study on 56 colostrum samples and 12 mature breast milk samples from 56 healthy donors using a method based on sequencing of bacterial 16S rRNA gene was conducted.Results. In a batch of 56 colostrum samples, 22 species and 242 genera of bacteria were identified. Firmicutes, Proteobacteria, Actinobacteriota were the most predominant species of bacteria in healthy women with a normal body mass index, from a physiological pregnancy, who did not take antibiotics, after natural delivery at term; Streptococcus, Staphylococcus and Gemella were the most predominant at the level of delivery. Statistical analysis of the impact of nationality, age, number of children in the family and duration of hospitalization (PERMANOVA) showed no significant differences in the proportions of bacteria in the colostrum of women (p > 0.05). The gender of the child was the only factor that turned out to be significant. The biodiversity of colostrum of girl-delivered mothers were higher (Shannon index) than that of boy-delivered mothers. In addition, the mature breast milk microbiota (1 month after delivery) has lower alpha diversity as compared to colostrum.Discussion. The analysis of our results and reports from foreign colleagues showed significant similarities and differences, which, certainly, were explained by a number of reasons related to methodological and geographical differences, the method, timing and even the time of day when breast milk samples were collected.Conclusion. In general, the colostrum of healthy women had a fairly stable bacterial composition, and its rich biodiversity fully demonstrated high quality of the first microbial inoculum for the newborn intestine. Our results provide valuable insights into the healthy breast milk microbiota in women living in the Russian Federation and can be used as reference ranges, as well as for comparison with similar indicators in women from other countries.

Koristi dojenja za majku i dete

Breastfeeding is the best way to feed a child from the first six months until the end of the second year. The unbreakable bond during pregnancy between a mother and her child continues during the lactation process, providing numerous benefits for both the mother and the child. Due to the effects of many hormones after childbirth, lactation offers numerous advantages for the mother. Oxytocin causes reduction of the uterus and bleeding, absence of menstruation, faster return of body weight, lower risk of cancer of the reproductive organs, and prevents the occurrence of osteoporosis and the development of the metabolic syndrome. Breastfeeding certainly ensures a better emotional bond with the child. Specificity in the composition of human milk provides the newborn with short-term and long-term protective effects. Thanks to human oligosaccharides, immunoglobulins, and polyunsaturated fatty acids that influence the composition of the microbiome of the newborn's intestine, as well as the formation of its immune response, breastfed children suffer less from respiratory and digestive infections, food allergies, autoimmune diseases and have been proven to have a higher IQ. Breastfeeding is the best form of feeding for mother and child. The specificity of the composition of human milk ensures optimal growth and development of the child and a healthier life for its mother.

Impact of maternal factors, environmental factors, and race on necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is a complex disease with a multifactorial etiology. As the leading cause of intestinal morbidity and mortality among premature infants, many resources are being dedicated to neonatal care and molecular targets in the newborn intestine. However, NEC is heavily influenced by maternal and perinatal factors as well. Given its nature, preventive approaches to NEC are more likely to improve outcomes than new treatment strategies. Therefore, this review focuses on maternal, environmental, and racial factors associated with the development of NEC, with an emphasis on those that may be modifiable to decrease the incidence of the disease.

Butyrate induces development-dependent necrotizing enterocolitis-like intestinal epithelial injury via necroptosis.

The accumulation of short-chain fatty acids (SCFAs) from bacterial fermentation may adversely affect the under-developed gut as observed in premature newborns at risk for necrotizing enterocolitis (NEC). This study explores the mechanism by which specific SCFA fermentation products may injure the premature newborn intestine mucosa leading to NEC-like intestinal cell injury. Intraluminal injections of sodium butyrate were administered to 14- and 28-day-old mice, whose small intestine and stool were harvested for analysis. Human intestinal epithelial stem cells (hIESCs) and differentiated enterocytes from preterm and term infants were treated with sodium butyrate at varying concentrations. Necrosulfonamide (NSA) and necrostatin-1 (Nec-1) were used to determine the protective effects of necroptosis inhibitors on butyrate-induced cell injury. The more severe intestinal epithelial injury was observed in younger mice upon exposure to butyrate (p = 0.02). Enterocytes from preterm newborns demonstrated a significant increase in sensitivity to butyrate-induced cell injury compared to term newborn enterocytes (p = 0.068, hIESCs; p = 0.038, differentiated cells). NSA and Nec-1 significantly inhibited the cell death induced by butyrate. Butyrate induces developmental stage-dependent intestinal injury that resembles NEC. A primary mechanism of cell injury in NEC is necroptosis. Necroptosis inhibition may represent a potential preventive or therapeutic strategy for NEC. Butyrate induces developmental stage-dependent intestinal injury that resembles NEC. A primary mechanism of cell injury caused by butyrate in NEC is necroptosis. Necroptosis inhibitors proved effective at significantly ameliorating the enteral toxicity of butyrate and thereby suggest a novel mechanism and approach to the prevention and treatment of NEC in premature newborns.

Lactobacillus derived from breast milk facilitates intestinal development in IUGR rats.

The intestinal microbiota contributes to infant's intestine homeostasis. This study aimed to analyse how probiotics derived from breast milk promote infant intestinal development in rat pups. The effect of potential probiotics derived from breast milk on development of intrauterine growth retardation (IUGR) newborn rats' intestine was investigated. Limosilactobacillus oris ML-329 and Lacticaseibacillus paracasei ML-446 exhibited good hydrophobicity percentages (p < 0.05). ML-446 showed a significant effect on intestinal length and weight (p < 0.05). Meanwhile, the villus height of the IUGR newborn rats fed with ML-329 was significantly higher compared with those fed with Lacticaseibacillus rhamnosus GG (p < 0.05). Moreover, ML-329 and ML-446 both significantly stimulated the proliferation and differentiation of intestinal epithelial cells by increasing the number of ki67-positive cells, goblet cells, and lysozyme-positive Paneth cells (p < 0.05) through Wnt and Notch pathway. The proliferation and differentiation stimulating effects of ML-329 and ML-446 on IECs in the jejunum, ileum, and colon were mediated by activating the Wnt pathway with increased expression of wnt, lrp5, and β-catenin genes and accumulation of β-catenin, and by downregulating the Notch signalling pathway with decreased expression of the activated notch protein. Lactobacillus could facilitate IUGR rat pups' intestinal development and enhance the proliferation of Paneth cells and goblet cells. These findings provide further insights into promotion of the intestinal development by breast milk-derived beneficial microbes in early life of the IUGR newborn rats.

A1 USING HUMAN NEONATAL ORGANOIDS TO EXPLORE GUT-IMMUNE SYSTEM INTERACTIONS OF THE NEONATAL INTESTINE

BackgroundNecrotizing Enterocolitis (NEC) affects around 10% of preterm babies and is one of the leading causes of death for newborns. NEC is characterized by exaggerated inflammation of the intestinal mucosa, possibly triggered by aberrant exposure to gut microbes, leading to hypoxic conditions and the death of intestinal tissues. It has been hypothesized that NEC develops when the immature intestine (epithelium and immune system) is unable to properly balance these new microbial interactions. To date, NEC is poorly understood and due to the difficulty of modeling the human neonatal intestine, few therapeutic options are available.Intestinal epithelial cells (IEC) are important players in promoting beneficial host-microbe interactions in the gut, being the primary barrier that separates the host’s mucosal immune system from luminal microbiota, as well as key players in mediating signaling between microbes and the host. Based on their location, IEC are also subject to injury associated with maladaptive immune responses against gut microbes. Many studies have shown that immune cells (such as T helper 17 cells) interact with IEC to promote gut health and function. These interactions include educating IEC on how to respond to, and fight pathogenic microbes, yet also remain tolerant to commensal microbes.AimsThis project seeks to develop an in vitro human neonatal intestinal organoid model to study developmental changes in IEC and their functional interactions with neonatal Th17 cells.Methods3D organoids were established from human neonatal intestinal biopsies and then co-cultured with the supernatant of differentiated Th17 cells or with recombinant cytokines, IL-17 and IL-22. Changes in barrier function, cell proliferation, production of mucins and anti-microbial peptides (AMP) were analyzed by qPCR and immunostaining.ResultsUsing 3D neonatal organoids we observed that the supernatants from neonatal Th17 cells (containing IL-17, IL-22 etc.) promoted the proliferation, differentiation and barrier function of the neonatal epithelium. By using specific recombinant cytokine (IL22, IL17) and neutralizing IL-22 antibodies in parallel, we demonstrated that the high levels of IL-22 produced by neonatal Th17 cells specifically induced proliferation of IEC, AMP and mucus production as compared to control media treated organoids, as shown by increases in Ki67, Reg3γ and Muc2 markers.ConclusionsThis experimental model mimicking the neonatal intestinal environment can be used to study interactions between neonatal IEC and immune cells. Our findings can provide clinically relevant information and clues to how developmental changes in the newborn intestine can influence susceptibility to NEC while demonstrating our development of a simple, yet accurate and clinically applicable model of the neonatal gut.Funding AgenciesCAG, CIHRBCCHRI, CCC, C.H.I.L.D. Fdn

Dominant bacteria and influencing factors of early intestinal colonization in very low birth weight infants: A prospective cohort study.

BackgroundThe intestine of newborns is colonized by bacteria immediately after birth. This study explored dominant bacteria and influencing factors of early intestinal colonization in the early life of very low birth weight infants (VLBWI).MethodsWe enrolled 81 VLBWI and collected anal swabs at 24 h, 7th, 14th and 21st day after birth. We conducted bacterial culture for anal swabs, then selected the colony with obvious growth advantages in the plate for further culture and identification. Afterward, we analyzed the distribution and influencing factors of intestinal dominant microbiota combined with clinical data.ResultsA total of 300 specimens were collected, of which 62.67% (188/300) had obvious dominant bacteria, including 29.26% (55/188) Gram‐positive bacteria and 70.74% (133/188) Gram‐negative bacteria. The top five bacteria with the highest detection rates were Klebsiella pneumoniae, Escherichia coli, Enterococcus faecium, Enterococcus faecalis and Serratia marcescens. Meconium‐stained amniotic fluid and chorioamnionitis were correlated with intestinal bacterial colonization within 24 h of birth. Mechanical ventilation and antibiotics were independent risk factors affecting colonization. Nosocomial infection of K. pneumoniae and S. marcescens were associated with intestinal colonization. The colonization rates of K. pneumoniae, E. coli, E. faecium, and E. faecalis increased with the birth time.ConclusionsThe colonization rate in the early life of VLBWI increased over time and the predominant bacteria were Gram‐negative bacteria. Meconium‐stained amniotic fluid and chorioamnionitis affect intestinal colonization in early life. Mechanical ventilation and antibiotics were independent risk factors for intestinal bacterial colonization. The nosocomial infection of some bacteria was significantly related to intestinal colonization.

Ontogeny of ROR\u03b3t+ cells in the intestine of newborns and its role in the development of experimental necrotizing enterocolitis

BackgroundNeonates possess an immature and plastic immune system, which is a major cause of some diseases in newborns. Necrotizing enterocolitis (NEC) is a severe and devastating intestinal disease that typically affects premature infants. However, the development of intestinal immune cells in neonates and their roles in the pathological process of NEC have not been elucidated.ResultsWe examined the ontogeny of intestinal lamina propria lymphocytes in the early life of mice and found a high percentage of RORγt+ cells (containing inflammatory Th17 and ILC3 populations) during the first week of life. Importantly, the proportion of RORγt+ cells of intestinal lamina propria further increased in both NEC mice and patients tissue than the control. Furthermore, the application of GSK805, a specific antagonist of RORγt, inhibited IL-17A release and ameliorated NEC severity.ConclusionsOur data reveal the high proportion of RORγt+ cells in newborn mice may directly contribute to the development of NEC.

FcRn is not the receptor mediating the transfer of serum IgG to colostrum in pigs.

In contrast to humans or rabbits, in which maternal IgG is transmitted to offspring prenatally via the placenta or the yolk sac, large domestic animals such as pigs, cows and sheep transmit IgG exclusively through colostrum feeding after delivery. The extremely high IgG content in colostrum is absorbed by newborns via the small intestine. Although it is widely accepted that the neonatal Fc receptor, FcRn, is the receptor mediating IgG transfer across both the placenta and small intestine, it remains unclear whether FcRn also mediates serum IgG transfer across the mammary barrier to colostrum/milk, especially in large domestic animals. In this study, using a FcRn knockout pig model generated with a CRISPR-Cas9-based approach, we clearly demonstrate that FcRn is not responsible for the IgG transfer from serum to colostrum in pigs, although like in other mammals, it is involved in IgG homeostasis and mediates IgG absorption in the small intestine of newborns.

Review article: key aspects of mammal microbiome development

This review article summarizes current understanding of the microbiota development in neonatal mammals based on the results of modern experimental studies in animals focusing on three aspects: initial colonization, microbiota effect on the immune function of the developing newborn animal intestine and external factors influencing the microbiome shaping during the juvenile period. The presented study results confirm that the microbial landscape correction is the most important factor for animal health improvement since healthy microflora contributes to the intestinal infection frequency and intensity reduction, and this, in turn, minimizes the use of antibiotics. The microbiome is known to have an impact on the immune system development, metabolic processes and even on the ethology, so an atypical microbial population can cause immune and metabolic disorders. The active interaction between microorganisms and the host organism begins already at birth. Even different modes of delivery (caesarean or vaginal delivery) may determine the initial colonization of the newborn. The animal genetics, nutrition and environment also influence the intestinal microbiota development. In this regard, further studies of probiotics are important to understand their efficacy for diarrhea prevention and treatment, their use as an alternative to antibiotics as well as for enhancement of the animal resistance to stress factors.

A bovine lactoferricin-lactoferrampin-encoding Lactobacillus reuteri CO21 regulates the intestinal mucosal immunity and enhances the protection of piglets against enterotoxigenic Escherichia coli K88 challenge

ABSTRACT Enterotoxigenic Escherichia coli (ETEC) is an important cause of diarrhea in human and animal. To determine the mechanism of a bovine lactoferricin-lactoferrampin (LFCA)-encoding Lactobacillus reuteri CO21 (LR-LFCA) to enhance the intestinal mucosal immunity, we used a newborn piglet intestine model to study the intestinal response to ETEC. Pigs were chosen due to the anatomical similarity between the porcine and the human intestine.4-day-old piglets were orally administered with LR-LFCA, LR-con (L. reuteri CO21 transformed with pPG612 plasmid) or phosphate buffered saline (PBS) for three consecutive days, within 21 days after these treatments, we found that LR-LFCA can colonize the intestines of piglets, improve the growth performance, enhance immune response and is beneficial for intestinal health of piglets by improving intestinal barrier function and modulating the composition of gut microbiota. Twenty-one days after, piglets were infected with ETEC K88 for 5 days, we found that oral administration of LR-LFCA to neonatal piglets attenuated ETEC-induced the weight loss of piglets and diarrhea incidence. LR-LFCA decreased the production of inflammatory factors and oxidative stress in intestinal mucosa of ETEC-infected piglets. Additionally, LR-LFCA increased the expression of tight junction proteins in the ileum of ETEC-infected piglets. Using LPS-induced porcine intestinal epithelial cells (IPEC-J2) in vitro, we demonstrated that LR-LFCA-mediated increases in the tight junction proteins might depend on the MLCK pathway; LR-LFCA might increase the anti-inflammatory ability by inhibiting the NF-κB pathway. We also found that LR-LFCA may enhance the antioxidant capacity of piglets by activating the Nrf2/HO-1 pathway. This study demonstrates that LR-LFCA is effective at maintaining intestinal epithelial integrity and host homeostasis as well as at repairing intestinal damage after ETEC infection and is thus a promising alternative therapeutic method for intestinal inflammation.

The effect of intestinal microbiota on pregnancy and baby's health

Introduction: The intestinal microflora (IM) is a heterogeneous complex of all microorganisms inhabiting the human body, both commensal, symbiotic and pathogenic. It consists mainly of bacteria, but also of viruses, archaea, fungi and protozoa. IM has an important metabolic and immunological role and participates in the course of pathological processes. The composition of a newborn and baby’s IM changes dynamically in the first year of life. Just in the first days of birth, the newborn is exposed to many different strains of bacteria, including Staphylococcus sp. and Enterococcus sp.Aim: To purpose of systematic review was to collect and analyze material of effect of the mother's gut microbiota on the pregnancy and of the health of baby.Material and methods: Review of the literature published in 2008-2020.Conclusion: The uterus environment was originally considered sterile and the newborn's intestines were to be colonized only during and after delivery. However, recent studies indicate that placenta and amniotic fluid are involved in microbiota colonization of fetal intestines during prenatal life. This means that the fetus has an initial stock of microorganisms before birth. In addition, a significant effect of maternal diet and probiotic supplementation during pregnancy on the composition of microorganisms found in the amniotic fluid has been demonstrated. There is also a relationship between microbiotic programming in the aspect of civilization diseases. Summary: The education of women of reproductive age on the subject of proper nutrition and supplementation during pregnancy and the puerperium is extremely important. Undertaking pro-health activities will affect the child's future health and development.

Maturation of Intestinal Oxygenation: A Review of Mechanisms and Clinical Implications for Preterm Neonates

Nutrient requirements of preterm neonates may be substantial, to support growth and maturation processes in the presence of challenging post-natal circumstances. This may be accompanied by substantial intestinal oxygen requirements. Preterm neonates may not be able to meet these oxygen requirements, due to a developmental delay in intestinal oxygenation regulation mechanisms. This review summarizes the available literature on post-natal maturation of intestinal oxygenation mechanisms and translates these changes into clinical observations and potential implications for preterm neonates. The different mechanisms that may be involved in regulation of intestinal oxygenation, regardless of post-natal age, are first discussed. The contribution of these mechanisms to intestinal oxygenation regulation is then evaluated in newborn and mature intestine. Finally, the course of clinical observations is used to translate these findings to potential implications for preterm neonates.

DYNAMICS OF MICROFLORA IN CALVES IN EARLY POSTEMBRIONAL ONTOGENESIS ON THE BACKGROUND OF BIOLOGICALLY ACTIVE SUBSTANCES AND ENTEROSORBENT APPLICATION

The problem of intestinal normocenosis formation in calves remains urgent. For species and quantitative assessment of the intestinal microbial landscape, it is sufficient to use standard methods of research throughout the period of newborn. Intensive operation of the industry requires the use of means of specific and non-specific protection of newborns’ body, among the latter the most promising are enterosorbents. Bifidobacteria actively reproduce during the newborn period. This is confirmed by their concentration at 15-day age: 1 x 108 CFU/g and 1 x 109 CFU/g, respectively, in calves of control and experimental groups, at starting - 1 x 106 CFU/g. Lactobacteria concentration in newborn calves increased from 1 x 104 CFU/g to 1 x 106 CFU/g in control 15-daily calves and 1 x 108 CFU/g of test groups. The most pronounced occupation properties were shown by the E. coli with normal enzymatic activity: in the intestine of newborns its concentration did not exceed 1 x 102 CFU/g, at 15-day age its content reached 1 x 106 CFU/g and 1 x 108 CFU/g in calves of control and experimental groups, respectively. In newborn calves, the concentration of enterococcus did not exceed 104 CFU/g, by 5-day age in all groups the amount increased to 105 CFU/g and remained the same up to 15-day age and only in 1 trial increased to 107 CFU/g. These species of microorganisms are bond-based and contribute to the maintenance of immunity and homeostasis in calves. It is not uncommon to detect opportunistic, pathogenic and transitive microorganisms in the intestinal contents of calves. In 5-day calves of the control group, clostridia (up to 103 CFU/g) were found, in 15-day calves, except for clostridia, hemolyzing E. coli and enterobacter (up to 106 CFU/g) were typed, which allows us to recommend oral use of enterosorbent suspension at a dose of 0.3 g/kg and 0.5 g/kg of live weight daily during the whole period.

Breast Milk and Microbiota in the Premature Gut: A Method of Preventing Necrotizing Enterocolitis.

Necrotizing enterocolitis (NEC) is a devastating inflammatory condition of the intestine, which affects premature infants and causes untold damage. Its pathogenesis has to do with how colonizing bacteria interact with the immature newborn intestine. An immature innate immune response with increased TLR-4 on the cell surface and increased signaling molecules, such as NF-κB, can cause excessive inflammation. This is in conjunction with a decrease in the appearance of regulatory molecules which effect the control of innate responses. This condition is so devastating that it must be prevented and not treated. Fortunately, breast milk and probiotics can affect the condition leading to reduced inflammation. How does this effect work? We have shown that breast milk tryptophan and Bifidobacterium infantis result in a metabolite (indole-3-lactic acid) response, which is anti-inflammatory via inhibition of the aryl hydrocarbon receptor transcription factor which stimulates an IL-8 response. We have also shown that breast milk complex carbohydrates interacting with Bacteroides fragilis can cause short-chain fatty acids which exert anti-inflammatory effects on the newborn intestine. These breast milk metabolites could help prevent NEC if shown to be effective clinically.

2843. Maternal Fecal Transplantation to Infants Born by Cesarean Section: Safety and Feasibility

BackgroundA complication of cesarean section delivery is its interference with the normal intestinal colonization of the infant, affecting the development of immune system in early life—a process that has been associated with long-term morbidity, such as allergy and diabetes. We evaluated, in CS-delivered infants, whether the normal intestinal microbiome and its early life development could be restored by immediate postnatal transfer of maternal fecal microbiota to the newborn.MethodsSeventeen healthy mothers with planned elective CS were recruited and screened thoroughly for infections, after which 7 mothers were included in the study. A fecal sample was processed according to a transplantation protocol and an aliquot (3–7 mg) was orally administered in breast-milk to the newborn during the first feeding. The infants were followed and fecal samples were gathered during the first 12 weeks of age and subsequently at the age of 8–18 months.ResultsThe bacterial communities in the fecal samples of the mothers and their offspring were analyzed by sequencing of 16S rRNA amplicons from isolated fecal DNA and compared with that of 11 nontreated CS-delivered infants and 34 vaginally delivered infants. The fecal microbiota at 3 and 12 weeks was similar between treated CS and vaginally delivered infants, in contrast to that of the untreated CS-delivered infants both in overall composition (P = 0.001, Figure) and development of early-life signature bacteria, i.e., bacteroides and bifidobacteria and clostridia (P < 0.0001).ConclusionThe seeding of maternal fecal microbes to the newborn intestine can be safely and successfully mimicked in elective CS by transferring a small amount of maternal fecal microbiome orally to the newborn infant. In these infants, this process results in a microbial development that is highly similar to that of the vaginally born infants, and provides support for the hypothesis that microbial colonization in early life results from a maternal fecal transfer. Disclosures All Authors: No reported Disclosures.

Endothelin receptor B affects the perfusion of newborn intestine: possible mechanism of necrotizing enterocolitis development.

Necrotizing enterocolitis (NEC) is one of the most severe gastrointestinal diseases in infancy. Hypoxia is known as one of the major risk factors for the development of NEC. Endothelin, known to regulate vasoconstriction, has two receptors (A and B). However, the role of endothelin receptor B (EDNRB) in neonatal intestinal injury remains unclear. We aimed to investigate whether EDNRB is involved in NEC pathophysiology. Following ethical approval (#44032), EDNRB hetero knockout mice pups (EDNRB±) and their wild-type (WT) littermates were studied. NEC was induced from postnatal day 5-9 (P5-P9) by hypoxia, gavage feeding of formula and administration of lipopolysaccharide. On P9, the ileum was harvested. NEC induction in WT mice was associated with mucosal injury. However, EDNRB± NEC mice had reduced mucosal injury. Similarly, EDNRB± mice had significantly lower expression of IL-6 mRNA compared to WT NEC mice. Pimonidazole immunostaining was also significantly lower in EDNRB± compared to WT NEC, suggesting reduced tissue hypoxia. Partial knockout of EDNRB results in reduced NEC severity and reduced tissue hypoxia. Intestinal perfusion and hypoxia are important elements of NEC pathogenesis. These findings are relevant to the understanding of NEC pathophysiology and to the development of novel preventive strategies for NEC.

Porcine Milk Exosome MiRNAs Attenuate LPS-Induced Apoptosis through Inhibiting TLR4/NF-κB and p53 Pathways in Intestinal Epithelial Cells.

Lipopolysaccharide (LPS) is a bacterial endotoxin that induces intestine inflammation. Milk exosomes improve the intestine and immune system development of newborns. This study aims to establish the protective mechanisms of porcine milk exosomes on the attenuation of LPS-induced intestinal inflammation and apoptosis. In vivo, exosomes prevented LPS-induced intestine damage and inhibited (p < 0.05) LPS-induced inflammation. In vitro, exosomes inhibited (p < 0.05) LPS-induced intestinal epithelial cells apoptosis (23% ± 0.4% to 12% ± 0.2%). Porcine milk exosomes also decreased (p < 0.05) the LPS-induced TLR4/NF-κB signaling pathway activation. Furthermore, exosome miR-4334 and miR-219 reduced (p < 0.05) LPS-induced inflammation through the NF-κB pathway and miR-338 inhibited (p < 0.05) the LPS-induced apoptosis via the p53 pathway. Cotransfection with these three miRNAs more effectively prevented (p < 0.05) LPS-induced cell apoptosis than these miRNAs individual transfection. The apoptosis percentage in the group cotransfected with the three miRNAs (14% ± 0.4%) was lower (p < 0.05) than that in the NC miRNA group (28% ± 0.5%), and also lower than that in each individual miRNA group. In conclusion, porcine milk exosomes protect the intestine epithelial cells against LPS-induced injury by inhibiting cell inflammation and protecting against apoptosis through the action of exosome miRNAs. The presented results suggest that the physiological amounts of miRNAs-enriched exosomes addition to infant formula could be used as a novel preventative measure for necrotizing enterocolitis.