Breast milk-transforming growth factor-β₂ specifically attenuates IL-1β-induced inflammatory responses in the immature human intestine via an SMAD6- and ERK-dependent mechanism

Extracellular Nicotinamide Phosphoribosyltransferase Is a Therapeutic Target in Experimental Necrotizing Enterocolitis

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency of prematurity. Postulated mechanisms leading to inflammatory necrosis of the ileum and colon include activation of the pathogen recognition receptor Toll-like receptor 4 (TLR4) and decreased levels of transforming growth factor beta (TGFβ). Extracellular nicotinamide phosphoribosyltransferase (eNAMPT), a novel damage-associated molecular pattern (DAMP), is a TLR4 ligand and plays a role in a number of inflammatory disease processes. To test the hypothesis that eNAMPT is involved in NEC, an eNAMPT-neutralizing monoclonal antibody, ALT-100, was used in a well-established animal model of NEC. Preterm Sprague-Dawley pups delivered prematurely from timed-pregnant dams were exposed to hypoxia/hypothermia and randomized to control-foster mother dam-fed rats, injected IP with saline (vehicle) 48 h after delivery; control + mAB-foster dam-fed rats, injected IP with 10 µg of ALT-100 at 48 h post-delivery; NEC-orally gavaged, formula-fed rats injected with saline; and NEC + mAb-formula-fed rats, injected IP with 10 µg of ALT-100 at 48 h. The distal ileum was processed 96 h after C-section delivery for histological, biochemical, molecular, and RNA sequencing studies. Saline-treated NEC pups exhibited markedly increased fecal blood and histologic ileal damage compared to controls (q < 0.0001), and findings significantly reduced in ALT-100 mAb-treated NEC pups (q < 0.01). Real-time PCR in ileal tissues revealed increased NAMPT in NEC pups compared to pups that received the ALT-100 mAb (p < 0.01). Elevated serum levels of tumor necrosis factor alpha (TNFα), interleukin 6 (IL-6), interleukin-8 (IL-8), and NAMPT were observed in NEC pups compared to NEC + mAb pups (p < 0.01). Finally, RNA-Seq confirmed dysregulated TGFβ and TLR4 signaling pathways in NEC pups that were attenuated by ALT-100 mAb treatment. These data strongly support the involvement of eNAMPT in NEC pathobiology and eNAMPT neutralization as a strategy to address the unmet need for NEC therapeutics.

Cytokines and Chemokines in Breastmilk of SARS-CoV-2 Infected or COVID-19 Vaccinated Mothers

INTRODUCTION

The COVID-19 disease and anti-SARS-CoV-2 vaccination were accompanied by alterations in several inflammatory markers. The aim of our research was to check to what extent such cytokines are transferred to infants via the breastmilk of SARS-CoV-2-infected or vaccinated mothers. Thus, we wanted to check if breastfeeding is safe during SARS-CoV-2 infection or after COVID-19 mRNA-vaccination.

MATERIAL AND METHOD

The Luminex Multiplexing Assay was used for quantifying 10 cytokine in the human breastmilk of SARS-CoV-2-infected or COVID-19-vaccinated mothers, compared with anti-SARS-CoV-2 IgG naïve mothers. Two milk samples were collected at 30 and 60 days either after the booster dose or afterthe onset of symptoms. A single milk sample was collected from the mothers within the control group.

RESULTS

The cytokine concentrations were mostly found within the reference intervals for all mothers. The status of the vaccinated/infected mother, the age of the breastfed child, the parity of the mother and the maternal age were variation factors of the above-mentioned cytokine concentrations. The type of birth and the presence of IgG in the milk had no influence on these cytokine concentrations in milk. Furthermore, no statistically significant differences were recorded between the cytokine concentrations of the two milk samples.

CONCLUSION

Our study provides data that support the safety of breastfeeding in the case of mild COVID-19 infection or after Pfizer or Moderna vaccinations.

Neonatal microbiota-epithelial interactions that impact infection

Despite modern therapeutic developments and prophylactic use of antibiotics during birth or in the first few months of life, enteric infections continue to be a major cause of neonatal mortality and morbidity globally. The neonatal period is characterized by initial intestinal colonization with microbiota and concurrent immune system development. It is also a sensitive window during which perturbations to the environment or host can significantly impact colonization by commensal microbes. Extensive research has demonstrated that these early life alterations to the microbiota can lead to enhanced susceptibility to enteric infections and increased systemic dissemination in newborns. Various contributing factors continue to pose challenges in prevention and control of neonatal enteric infections. These include alterations in the gut microbiota composition, impaired immune response, and effects of maternal factors. In addition, there remains limited understanding for how commensal microbes impact host-pathogen interactions in newborns. In this review, we discuss the recent recognition of initial microbiota-epithelial interactions that occur in neonates and can regulate susceptibility to intestinal infection. These studies suggest the development of neonatal prophylactic or therapeutic regimens that include boosting epithelial defense through microbiota-directed interventions.

Necrotizing Enterocolitis: Clinical Features, Histopathological Characteristics, and Genetic Associations

Necrotizing enterocolitis (NEC) is an inflammatory bowel necrosis seen in premature infants. Although the etiopathogenesis of NEC is unclear, genetic factors may alter a patient's susceptibility, clinical course, and outcomes. This review draws from existing studies focused on individual genes and others based on microarray-based high-throughput discovery techniques. We have included evidence from our own studies and from an extensive literature search in the databases PubMed, EMBASE, and Scopus. To avoid bias in the identification of studies, keywords were short-listed a priori from anecdotal experience and PubMed's Medical Subject Heading (MeSH) thesaurus.

Profile of pro-inflammatory cytokines in colostrum of nursing mothers at the extremes of reproductive age

Gestations at the extremes of reproductive age are characterized as high-risk pregnancies, conditions that might influence colostrum composition. This first milk secretion contains nutrients necessary for the development and immunity of the newborn; therefore, this study aims to compare adolescent and advanced maternal age mothers regarding sociodemographic, gestational, and perinatal characteristics and the colostrum levels of pro-inflammatory cytokines in these groups of study. This cross-sectional study has compared sociodemographic, gestational and perinatal data from adolescent mothers (between 10 and 24 years old) (n = 117), advanced maternal age mothers (over 35 years of age) (n = 39) and mothers considered a control group (25 to 34 years old) (n = 58). Additionally, colostrum samples were obtained from the studied and control group subjects by manual milking, between 48 and 72 hours postpartum, and the samples were analyzed for cytokine concentrations by enzyme-linked immunosorbent assay (ELISA). The majority of the studied mothers reported living a stable union, and 81.2% of the adolescent mothers did not carry out any paid activity. Mothers with advanced maternal age mainly delivered by cesarean section and presented a higher body mass index (BMI). Neonatal weight and Apgar score were not different between the groups. The concentrations of interleukin (IL)-1β and IL-6 were higher in the colostrum of mothers with advanced age compared to adolescent mothers, but did not differ from the control group. The concentrations of IL-8 and tumor necrosis factor alpha did not differ between the three groups. Therefore, our data demonstrated that maternal age influenced the sociodemographic and gestational characteristics as well as the composition of colostrum cytokines.

Comparative analysis of whey proteins in donkey colostrum and mature milk using quantitative proteomics

Donkey milk is attracting increasing attention as a nutritional milk source similar to human milk. In this study, we carried out qualitative and quantitative analysis of the donkey whey proteome using a label-free proteomic approach, combined with parallel reaction monitoring (PRM) as a validation method. A total of 300 whey proteins were identified in donkey colostrum (DC) and donkey mature (DM) milk, of which 18 were differentially expressed (P < 0.05) between the two types of milk. Gene ontology (GO) analysis showed that differentially and uniquely expressed proteins were mainly involved in cellular processes, response to stimulus, metabolic processes, and biological regulation. Their molecular functions included binding, catalytic activity, and molecular functional regulation, and their main annotated areas of origin were the cell, cell-part, and the extracellular region. Most differentially and uniquely expressed proteins were linked with malaria, systemic lupus erythematosus, or antigen processing and presentation. Our results provide insight into the complexity of the donkey whey proteome and molecular evidence for nutritional differences between different lactation stages.

Transforming growth factor beta in human milk and allergic outcomes in children: A systematic review

BACKGROUND

Human milk (HM) transforming growth factor beta (TGF-β) is critical for inflammation regulation and oral tolerance promotion. Previous reports suggested that variations in HM TGF-β levels are associated with allergic outcomes.

OBJECTIVE

We undertook a systematic review (PROSPERO 2017 CRD42017069920) to reassess the evidence on the relationships between HM TGF-β and allergic outcomes in children.

METHODS

Electronic bibliographic databases (MEDLINE, EMBASE and Cochrane Library) were systematically searched. Two independent reviewers screened reference lists, extracted the data and assessed risk of bias using the National Institute for Clinical Excellence methodological checklist.

RESULTS

A total of 21 studies were identified. Sixteen studies assessed relationships between HM TGF-β and risk of eczema; 14, allergic sensitization; nine, wheezing/asthma; six, food allergy; three, allergic rhinitis/conjunctivitis. Five cohorts (5/18, 28%) reported a protective effect of TGF-β1, while 3 (3/10, 30%) suggested increased risk of allergic outcomes development and 1 (1/10, 10%), a protective effect of TGF-β2 on eczema. Meta-analysis was not possible due to significant heterogeneity in methodology, age of outcome assessment and differing statistical approaches. 71% (15/21) of studies carried a high risk of bias.

CONCLUSION AND CLINICAL RELEVANCE

In contrast with previous findings, we did not find strong evidence of associations between HM TGF-β and allergic outcomes. Differences in studies' methodology and outcomes do not allow unconditional rejection or acceptance of the hypothesis that HM TGF-β influences the risk of allergy development. Future studies on diverse populations employing standardized methods, accurate phenotyping of outcomes and evaluation of the effect of TGF-β in combination with other HM immune markers, microbiome and oligosaccharides are required.

Impact of human milk on the transcriptomic response of fetal intestinal epithelial cells reveals expression changes of immune-related genes

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment.

Human milk, the best food for infants, is a dynamic and complex fluid that directly influences the immune system and microbiota establishment. The protective role of human milk is well known although the mechanisms behind it still need to be uncovered. This study aimed to characterize the impact of human milk in the immature intestine of newborns by analyzing the global transcriptomic response of the FHs 74 int cell line (ATCC CCL-241). The expression of intestinal keratins and other genes with a well-annotated intestinal or epithelial function validated FHs 74 int derived from the fetal small intestine as a model of the intestinal epithelium of newborns. Cells exposed to skimmed human milk showed seventeen differentially expressed genes, most of them up-regulated, including four chemokine genes (CXCL1, CXCL2, CXCL3 and CXCL10) and other immune-related genes. qRT-PCR and ELISA analysis confirmed the microarray data and indicated a different pattern of expression upon milk exposure in FHs 74 int as compared to the adult tumorigenic Caco-2 cell line. The evaluation of the functional significance of these transcriptomic changes reveals that human milk exposure may contribute to the regulation of the inflammatory response in the intestine during the perinatal period, which is characterized by the immaturity of the immune system and a pro-inflammatory phenotype.

Inherited nongenetic influences on the gut microbiome and immune system

The gut microbiome and the immune system codevelop around the time of birth, well after genetic information has been passed from the parents to the offspring. Each of these "organ systems" displays plasticity. The immune system can mount highly specific adaptive responses to newly encountered antigens, and the gut microbiota is affected by changes in the environment. Despite this plasticity, there is a growing appreciation that these organ systems, once established, are remarkably stable. In health, the immune system rapidly mounts responses to infections, and once cleared, resolves inflammatory responses to return to homeostasis. However, a skewed immune system, such as seen in allergy, does not easily return to homeostasis. Allergic responses are often seen to multiple antigens. Likewise, a dysbiotic gut microbiota is seen in multiple diseases. Attempts to reset the gut microbiota as a therapy for disease have met with varied success. Therefore, how these codeveloping "organ systems" become established is a central question relevant to our overall health. Recent observations suggest that maternal factors encountered both in utero and after birth can directly or indirectly impact the development of the offspring's gut microbiome and immune system. Here, we discuss how these nongenetic maternal influences can have long-term effects on the progeny's health.

Antibody Profile of Colostrum and the Effect of Processing in Human Milk Banks: Implications in Immunoregulatory Properties

BACKGROUND

When feeding preterm infants, donor milk is preferred if the mother's own milk is unavailable. Pasteurization may have detrimental effects on bioactivity, but more information is needed about its effects on the immunological compounds. Research aim: This work has two main aims: evaluate the antibody profile of colostrum and study the quantitative variations in the antibodies' level and specific reactivity after undergoing Holder pasteurization. The authors focused on immunoregulatory components of colostrum (antidietary antibodies and TGF-β2) in the neonatal gut.

METHODS

This is a descriptive cross-sectional study of a convenience sample of 67 donated colostrum samples at different days after delivery, both raw and pasteurized. Antibody profiles were analyzed at different times during breastfeeding, and total and specific antibodies (IgM, IgA, and IgG subclasses) were compared with tetanus toxoid and ovalbumin using enzyme-linked immunosorbent assay. The processing effect on total and specific antibodies, as well as TGF-β2, was evaluated by paired analyses.

RESULTS

No variations in immunological compounds were observed throughout the colostrum stage. The TGF-β2, antibodies' concentrations, and antibodies' specific reactivity after pasteurization did not vary significantly as days of lactation varied. Changes in antibody levels were dependent on isotype and IgG subclass, and IgG4 showed remarkable resistance to heating. Moreover, the effect of the pasteurization on specific reactivity was antigen dependent.

CONCLUSION

The supply of relevant immunological components is stable throughout the colostrum stage. The effects of pasteurization on antibodies depend on isotype, subclass, and specificity. This information is relevant to improving the immunological quality of colostrum, especially for preterm newborns.

Effect of HTST and Holder Pasteurization on the Concentration of Immunoglobulins, Growth Factors, and Hormones in Donor Human Milk

Donor human milk (DHM) is submitted to Holder pasteurization (HoP) to ensure its microbiological safety in human milk banks but this treatment affects some of its bioactive compounds. The objective of this work was to compare the effects of HoP and high temperature short time (HTST) treatments on some bioactive compounds found in DHM. A total of 24 DHM batches were processed in a continuous HTST system (70, 72, and 75°C for 5-25 s) and by HoP (62.5°C for 30 min). The concentrations of immunoglobulins (Igs) A, G, and M, transforming growth factor-beta 2 (TGF-β₂), adiponectine, ghrelin, and leptin were measured using a multiplex system, whereas the concentration of epidermal growth factor (EGF) was determined by ELISA. In relation to Igs, IgG showed the highest preservation rates (87-101%) after HTST treatments, followed by IgA (54-88%) and IgM (25-73%). Ig retention after any of the HTST treatments was higher than after HoP (p < 0.001). Treatment times required to reduce the concentration of IgM by 90% (D-value) were 130, 88, and 49 s at 70, 72, and 75°C, while the number of degrees Celsius required to change the D-value by one factor of 10 (z-value) was 11.79°C. None of the heat treatments had a significant effect on the concentrations of TGF-β₂, EGF, adiponectin, and ghrelin. In contrast, leptin was detected only in 4 of the samples submitted to HoP, whereas it was present in all samples after the different HTST treatments, with retention rates ranging between 34 and 68%. Globally, the concentration of IgA, IgG, IgM, and leptin in DHM was significantly higher after HTST pasteurization performed in a continuous system designed to be used in human milk banks than after the HoP procedure that is routinely applied at present.

Cytokines in milk and the role of TGF-beta

Cytokines are required for normal growth and development of the mammary gland and TGF-β prominently represents an established effector of apoptosis, e.g., during involution of the mammary gland. By the control of intracellular signaling pathways, including JAK/STAT, MAPK, PI-3K, and NF-κB, cytokines efficiently regulate cell proliferation and inflammation in the breast. Therefore, cytokines are discussed also in a context of malignant mammary growth. As a group of tissue hormones produced by somatic cells or by cells from the immune system, cytokines are defined by their immunomodulatory potential. Over the past 40 years, multiple cytokines were identified in colostrum and milk. Importantly, cytokines derived from mammary secretions after birth are required for maturation of the immune system in the developing gastrointestinal tract from the suckling. Moreover, recent studies have further assessed the particular interactions between probiotic bacterial strains and cytokines. In light of the increasing prevalence of inflammatory diseases of the gastrointestinal system, the effects of probiotic microorganisms during milk fermentation may have immunotherapeutic potential in the future.

The importance of appropriate initial bacterial colonization of the intestine in newborn, child, and adult health

The fetus does not reside in a sterile intrauterine environment and is exposed to commensal bacteria from the maternal gut/blood stream that cross the placenta and enter the amniotic fluid. This intestinal exposure to colonizing bacteria continues at birth and during the first year of life and has a profound influence on lifelong health. Why is this important? Intestinal crosstalk with colonizing bacteria in the developing intestine affects the infant's adaptation to extrauterine life (immune homeostasis) and provides protection against disease expression (allergy, autoimmune disease, obesity, etc.) later in life. Colonizing intestinal bacteria are critical to the normal development of host defense. Disrupted colonization (dysbiosis) due to maternal dysbiosis, cesarean section delivery, use of perinatal antibiotics, or premature delivery may adversely affect the gut development of host defense and predispose to inflammation rather than to homeostasis, leading to increased susceptibility to disease later in life. Babies born by cesarean section have a higher incidence of allergy, type 1 diabetes, and obesity. Infants given repeated antibiotic regimens during the first year of life are more likely to have asthma as adolescents. This research breakthrough helps to explain the shift in disease paradigms from infections to immune-mediated in children from developed countries. This review will develop this research breakthrough.

Breast Milk Transforming Growth Factor β Is Associated With Neonatal Gut Microbial Composition

BACKGROUND AND OBJECTIVES

Breast milk is a complex bioactive fluid that varies across numerous maternal and environmental conditions. Although breast-feeding is known to affect neonatal gut microbiome, the milk components responsible for this effect are not well-characterized. Given the wide range of immunological activity breast milk cytokines engage in, we investigated 3 essential breast milk cytokines and their association with early life gut microbiota.

METHODS

A total of 52 maternal-child pairs were drawn from a racially diverse birth cohort based in Detroit, Michigan. Breast milk and neonatal stool specimens were collected at 1-month postpartum. Breast milk transforming growth factor (TGF)β1, TGFβ2, and IL-10 were assayed using enzyme-linked immunosorbent assays, whereas neonatal gut microbiome was profiled using 16S rRNA sequencing.

RESULTS

Individually, immunomodulators TGFβ1 and TGFβ2 were significantly associated with neonatal gut microbial composition (R = 0.024, P = 0.041; R = 0.026, P = 0.012, respectively) and increased richness, evenness, and diversity, but IL-10 was not. The effects of TGFβ1 and TGFβ2, however, were not independent of one another, and the effect of TGFβ2 was stronger than that of TGFβ1. Higher levels of TGFβ2 were associated with the increased relative abundance of several bacteria, including members of Streptococcaceae and Ruminococcaceae, and lower relative abundance of distinct Staphylococcaceae taxa.

CONCLUSIONS

Breast milk TGFβ concentration explains a portion of variability in gut bacterial microbiota composition among breast-fed neonates. Whether TGFβ acts in isolation or jointly with other bioactive components to alter bacterial composition requires further investigation. These findings contribute to an increased understanding of how breast-feeding affects the gut microbiome-and potentially immune development-in early life.

What's Normal? Immune Profiling of Human Milk from Healthy Women Living in Different Geographical and Socioeconomic Settings

Human milk provides a very wide range of nutrients and bioactive components, including immune factors, human milk oligosaccharides, and a commensal microbiota. These factors are essential for interconnected processes including immunity programming and the development of a normal infant gastrointestinal microbiome. Newborn immune protection mostly relies on maternal immune factors provided through milk. However, studies dealing with an in-depth profiling of the different immune compounds present in human milk and with the assessment of their natural variation in healthy women from different populations are scarce. In this context, the objective of this work was the detection and quantification of a wide array of immune compounds, including innate immunity factors (IL1β, IL6, IL12, INFγ, TNFα), acquired immunity factors (IL2, IL4, IL10, IL13, IL17), chemokines (IL8, Groα, MCP1, MIP1β), growth factors [IL5, IL7, epidermal growth factor (EGF), granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, TGFβ2], and immunoglobulins (IgA, IgG, IgM), in milk produced by healthy women of different ethnicities living in different geographic, dietary, socioeconomic, and environmental settings. Among the analyzed factors, IgA, IgG, IgM, EGF, TGFβ2, IL7, IL8, Groα, and MIP1β were detected in all or most of the samples collected in each population and, therefore, this specific set of compounds might be considered as the "core" soluble immune factors in milk produced by healthy women worldwide. This approach may help define which immune factors are (or are not) common in milk produced by women living in various conditions, and to identify host, lifestyle, and environmental factors that affect the immunological composition of this complex biological fluid. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02670278.

Cytokines and growth factors in the developing intestine and during necrotizing enterocolitis

Cytokines and growth factors play diverse roles in the uninflamed fetal/neonatal intestinal mucosa and in the development of inflammatory bowel injury during necrotizing enterocolitis (NEC). During gestational development and the early neonatal period, the fetal/premature intestine is exposed to high levels of many "inflammatory" cytokines and growth factors, first via swallowed amniotic fluid in utero and then, after birth, in colostrum and mother's milk. This article reviews the dual, seemingly counter-intuitive roles of cytokines, where these agents play a "trophic" role and promote maturation of the uninflamed mucosa, but can also cause inflammation and promote intestinal injury during NEC.

Opposing roles of TGF-β in prostaglandin production by human follicular dendritic cell-like cells

Prostaglandins (PGs) are recognized as important immune regulators. Using human follicular dendritic cell (FDC)-like HK cells, we have investigated the immunoregulatory role of PGs and their production mechanisms. The present study was aimed at determining the role of TGF-β in IL-1β-induced cyclooxygenase-2 (COX-2) expression by immunoblotting. COX-2 is the key enzyme responsible for PG production in HK cells. TGF-β, when added simultaneously with IL-1β, gave rise to an additive effect on COX-2 expression in a dose-dependent manner. However, TGF-β inhibited IL-1β-stimulated COX-2 expression when it was added at least 12h before IL-1β addition. The inhibitory effect of TGF-β was specific to IL-1β-induced COX-2 expression in HK cells. The stimulating and inhibitory effects of TGF-β were reproduced in IL-1β-stimulated PG production. Based on our previous results of the essential requirement of ERK and p38 MAPKs in TGF-β-induced COX-2 expression, we examined whether the differential activation of these MAPKs would underlie the opposing activities of TGF-β. The phosphorylation of ERK and p38 MAPKs was indeed enhanced or suppressed by the simultaneous treatment or pre-treatment, respectively. These results suggest that TGF-β exerts opposing effects on IL-1β-induced COX-2 expression in HK cells by differentially regulating activation of ERK and p38 MAPKs.

Hydrocortisone-induced anti-inflammatory effects in immature human enterocytes depend on the timing of exposure

The immature human gut has a propensity to exaggerated inflammatory responses that are thought to play a role in the pathogenesis of necrotizing enterocolitis (NEC). Prenatal exposure to corticosteroids has been reported to reduce the risk of NEC, while postnatal dexamethasone treatment is associated with adverse neurodevelopmental outcomes in preterm infants. The aim of this study was to investigate the direct role of hydrocortisone in gene expression patterns and inflammatory responses in immature human enterocytes. Time-dependent hydrocortisone effects in nontransformed primary human fetal intestinal epithelial cell line H4 were investigated by cDNA microarray. Fetal intestinal organ culture and cell culture experiments were conducted. Inflammatory responses were induced by stimulation with IL-1β and TNF-α with and without hydrocortisone. IL-8 and IL-6 expression and secretion were measured as functional readout. Here we report time-dependent hydrocortisone-induced changes in gene expression patterns detected by cDNA microarray. Hydrocortisone significantly attenuated IL-1β-induced inflammatory responses in the immature human gut when administered at the time of the proinflammatory insult: IL-1β-induced IL-8 and IL-6 secretion in the fetal ileum as well as H4 cells were significantly reduced. Hydrocortisone also inhibited IL-8 secretion in response to TNF-α. In contrast, TNF-α-induced IL-8 secretion was not reduced in cells treated with hydrocortisone for 48 h before stimulation. Our observations provide a physiological basis for understanding the differential clinical effects of corticosteroids in the immature human gut depending on the timing of treatment.

Bioactive factors in milk across lactation: Maternal effects and influence on infant growth in rhesus macaques (Macaca mulatta)

Among mammals, numerous bioactive factors in milk vary across mothers and influence offspring outcomes. This emerging area of research has primarily investigated such dynamics within rodent biomedical models, domesticated dairy breeds, and among humans in clinical contexts. Less understood are signaling factors in the milk of non-human primates. Here, we report on multiple bioactive components in rhesus macaque (Macaca mulatta) milk and their associations with maternal and infant characteristics. Milk samples were collected from 59 macaques at multiple time points across lactation in conjunction with maternal and infant morphometrics and life-history animal records. Milk was assayed for adiponectin (APN), epidermal growth factor (EGF) and its receptor (EGF-R), and transforming growth factor beta 2 (TGF-β2 ). Regression models were constructed to assess the contributions of maternal factors on variation in milk bioactives, and on the relationship of this variation to infant body mass and growth. Maternal body mass, parity, social rank, and infant sex were all predictive of concentrations of milk bioactives. Primiparous mothers produced milk with higher adiponectin, but lower EGF, than multiparous mothers. Heavier mothers produced milk with lower EGF and EGF-R, but higher TGF-β2 . Mothers of daughters produced milk with higher TGF-β2 . Mid-ranking mothers produced milk with higher mean EGF and adiponectin concentrations than low-ranking mothers. Milk EGF and EGF-R were positively associated with infant body mass and growth rate. Importantly, these signaling bioactives (APN, EGF, EGF-R, and TGF-β2 ) were significantly correlated with nutritional values of milk. The effects of milk signals remained after controlling for the available energy in milk revealing the added physiological role of non-nutritive milk bioactives in the developing infant. Integrating analyses of energetic and other bioactive components of milk yields an important perspective for interpreting the magnitude, sources, and consequences of inter-individual variation in milk synthesis. Am. J. Primatol. 78:838-850, 2016. © 2016 Wiley Periodicals, Inc.

Whey protein concentrate enhances intestinal integrity and influences transforming growth factor-β1 and mitogen-activated protein kinase signalling pathways in piglets after lipopolysaccharide challenge

Whey protein concentrate (WPC) has been reported to have protective effects on the intestinal barrier. However, the molecular mechanisms involved are not fully elucidated. Transforming growth factor-β1 (TGF-β1) is an important component in the WPC, but whether TGF-β1 plays a role in these processes is not clear. The aim of this study was to investigate the protective effects of WPC on the intestinal epithelial barrier as well as whether TGF-β1 is involved in these protection processes in a piglet model after lipopolysaccharide (LPS) challenge. In total, eighteen weanling pigs were randomly allocated to one of the following three treatment groups: (1) non-challenged control and control diet; (2) LPS-challenged control and control diet; (3) LPS+5 %WPC diet. After 19 d of feeding with control or 5 %WPC diets, pigs were injected with LPS or saline. At 4 h after injection, pigs were killed to harvest jejunal samples. The results showed that WPC improved (P<0·05) intestinal morphology, as indicated by greater villus height and villus height:crypt depth ratio, and intestinal barrier function, which was reflected by increased transepithelial electrical resistance and decreased mucosal-to-serosal paracellular flux of dextran (4 kDa), compared with the LPS group. Moreover, WPC prevented the LPS-induced decrease (P<0·05) in claudin-1, occludin and zonula occludens-1 expressions in the jejunal mucosae. WPC also attenuated intestinal inflammation, indicated by decreased (P<0·05) mRNA expressions of TNF-α, IL-6, IL-8 and IL-1β. Supplementation with WPC also increased (P<0·05) TGF-β1 protein, phosphorylated-Smad2 expression and Smad4 and Smad7 mRNA expressions and decreased (P<0·05) the ratios of the phosphorylated to total c-jun N-terminal kinase (JNK) and p38 (phospho-JNK:JNK and p-p38:p38), whereas it increased (P<0·05) the ratio of extracellular signal-regulated kinase (ERK) (phospho-ERK:ERK). Collectively, these results suggest that dietary inclusion of WPC attenuates the LPS-induced intestinal injury by improving mucosal barrier function, alleviating intestinal inflammation and influencing TGF-β1 canonical Smad and mitogen-activated protein kinase signalling pathways.

Differential Expression of the Activator Protein 1 Transcription Factor Regulates Interleukin-1ß Induction of Interleukin 6 in the Developing Enterocyte

The innate immune response is characterized by activation of transcription factors, nuclear factor kappa B and activator protein-1 and their downstream targets, the pro-inflammatory cytokines including interleukin 1β and interleukin 6. Normal development of this response in the intestine is critical to survival of the human neonate and delays can cause the onset of devastating inflammatory diseases such as necrotizing enterocolitis. Previous studies have addressed the role of nuclear factor kappa B in the development of the innate immune response in the enterocyte, however despite its central role in the control of multiple pro-inflammatory cytokine genes, little is known on the role of Activator Protein 1 in this response in the enterocyte. Here we show that the canonical Activator Protein 1 members, cJun and cFos and their upstream kinases JNK and p38 play an essential role in the regulation of interleukin 6 in the immature enterocyte. Our data supports a model whereby the cFos/cJun heterodimer and the more potent cJun homodimer downstream of JNK are replaced by less efficient JunD containing dimers, contributing to the decreased responsiveness to interleukin 1β and decreased interleukin 6 secretion observed in the mature enterocyte. The tissue specific expression of JunB in colonocytes and colon derived tissues together with its ability to repress Interleukin-1β induction of an Interleukin-6 gene reporter in the NCM-460 colonocyte suggests that induction of JunB containing dimers may offer an attractive therapeutic strategy for the control of IL-6 secretion during inflammatory episodes in this area of the intestine

Transforming growth factor-β2 is sequestered in preterm human milk by chondroitin sulfate proteoglycans

Human milk contains biologically important amounts of transforming growth factor-β2 isoform (TGF-β2), which is presumed to protect against inflammatory gut mucosal injury in the neonate. In preclinical models, enterally administered TGF-β2 can protect against experimental necrotizing enterocolitis, an inflammatory bowel necrosis of premature infants. In this study, we investigated whether TGF-β bioactivity in human preterm milk could be enhanced for therapeutic purposes by adding recombinant TGF-β2 (rTGF-β2) to milk prior to feeding. Milk-borne TGF-β bioactivity was measured by established luciferase reporter assays. Molecular interactions of TGF-β2 were investigated by nondenaturing gel electrophoresis and immunoblots, computational molecular modeling, and affinity capillary electrophoresis. Addition of rTGF-β2 (20-40 nM) to human preterm milk samples failed to increase TGF-β bioactivity in milk. Milk-borne TGF-β2 was bound to chondroitin sulfate (CS) containing proteoglycan(s) such as biglycan, which are expressed in high concentrations in milk. Chondroitinase treatment of milk increased the bioactivity of both endogenous and rTGF-β2, and consequently, enhanced the ability of preterm milk to suppress LPS-induced NF-κB activation in macrophages. These findings provide a mechanism for the normally low bioavailability of milk-borne TGF-β2 and identify chondroitinase digestion of milk as a potential therapeutic strategy to enhance the anti-inflammatory effects of preterm milk.

All-Trans Retinoic Acid Induces TGF-β2 in Intestinal Epithelial Cells via RhoA- and p38α MAPK-Mediated Activation of the Transcription Factor ATF2

Objective

We have shown previously that preterm infants are at risk of necrotizing enterocolitis (NEC), an inflammatory bowel necrosis typically seen in infants born prior to 32 weeks’ gestation, because of the developmental deficiency of transforming growth factor (TGF)-β₂ in the intestine. The present study was designed to investigate all-trans retinoic acid (atRA) as an inducer of TGF-β₂ in intestinal epithelial cells (IECs) and to elucidate the involved signaling mechanisms.

Methods

AtRA effects on intestinal epithelium were investigated using IEC6 cells. TGF-β₂ expression was measured using reverse transcriptase-quantitative polymerase chain reaction (RT-qPCR) and Western blots. Signaling pathways were investigated using Western blots, transiently-transfected/transduced cells, kinase arrays, chromatin immunoprecipitation, and selective small molecule inhibitors.

Results

AtRA-treatment of IEC6 cells selectively increased TGF-β₂ mRNA and protein expression in a time- and dose-dependent fashion, and increased the activity of the TGF-β₂ promoter. AtRA effects were mediated via RhoA GTPase, Rho-associated, coiled-coil-containing protein kinase 1 (ROCK1), p38α MAPK, and activating transcription factor (ATF)-2. AtRA increased phospho-ATF2 binding to the TGF-β₂ promoter and increased histone H2B acetylation in the TGF-β₂ nucleosome, which is typically associated with transcriptional activation.

Conclusions

AtRA induces TGF-β₂ expression in IECs via RhoA- and p38α MAPK-mediated activation of the transcription factor ATF2. Further studies are needed to investigate the role of atRA as a protective/therapeutic agent in gut mucosal inflammation.

Early microbial contact, the breast milk microbiome and child health

The significance of contact with microbes in early life for subsequent health has been the subject of intense research during the last 2 decades. Disturbances in the establishment of the indigenous intestinal microbiome caused by cesarean section delivery or antibiotic exposure in early life have been linked to the risk of immune-mediated and inflammatory conditions such as atopic disorders, inflammatory bowel disease and obesity later in life. Distinct microbial populations have recently been discovered at maternal sites including the amniotic cavity and breast milk, as well as meconium, which have previously been thought to be sterile. Our understanding of the impact of fetal microbial contact on health outcomes is still rudimentary. Breast milk is known to modulate immune and metabolic programming. The breast milk microbiome is hypothesized to guide infant gut colonization and is affected by maternal health status and mode of delivery. Immunomodulatory factors in breast milk interact with the maternal and infant gut microbiome and may mediate some of the health benefits associated with breastfeeding. The intimate connection between the mother and the fetus or the infant is a potential target for microbial therapeutic interventions aiming to support healthy microbial contact and protect against disease.

Protective effects of transforming growth factor β2 in intestinal epithelial cells by regulation of proteins associated with stress and endotoxin responses

Transforming growth factor (TGF)-β2 is an important anti-inflammatory protein in milk and colostrum. TGF-β2 supplementation appears to reduce gut inflammatory diseases in early life, such as necrotizing enterocolitis (NEC) in young mice. However, the molecular mechanisms by which TGF-β2 protects immature intestinal epithelial cells (IECs) remain to be more clearly elucidated before interventions in infants can be considered. Porcine IECs PsIc1 were treated with TGF-β2 and/or lipopolysaccharide (LPS), and changes in the cellular proteome were subsequently analyzed using two-dimensional gel electrophoresis-MS and LC-MS-based proteomics. TGF-β2 alone induced the differential expression of 13 proteins and the majority of the identified proteins were associated with stress responses, TGF-β and Toll-like receptor 4 signaling cascades. In particular, a series of heat shock proteins had similar differential trends as previously shown in the intestine of NEC-resistant preterm pigs and young mice. Furthermore, LC-MS-based proteomics and Western blot analyses revealed 20 differentially expressed proteins following treatment with TGF-β2 in LPS-challenged IECs. Thirteen of these proteins were associated with stress response pathways, among which five proteins were altered by LPS and restored by TGF-β2, whereas six were differentially expressed only by TGF-β2 in LPS-challenged IECs. Based on previously reported biological functions, these patterns indicate the anti-stress and anti-inflammatory effects of TGF-β2 in IECs. We conclude that TGF-β2 of dietary or endogenous origin may regulate the IEC responses against LPS stimuli, thereby supporting cellular homeostasis and innate immunity in response to bacterial colonization, and the first enteral feeding in early life.

Oropharyngeal colostrum administration in extremely premature infants: an RCT

OBJECTIVE

To determine the immunologic effects of oropharyngeal colostrum administration in extremely premature infants.

METHODS

We conducted a double-blind, randomized, placebo-controlled trial involving 48 preterm infants born before 28 weeks' gestation. Subjects received 0.2 mL of their mother's colostrum or sterile water via oropharyngeal route every 3 hours for 3 days beginning at 48 to 96 hours of life. To measure concentrations of secretory immunoglobulin A, lactoferrin, and several immune substances, urine and saliva were obtained during the first 24 hours of life and at 8 and 15 days. Clinical data during hospitalization were collected.

RESULTS

Urinary levels of secretory immunoglobulin A at 1 week (71.4 vs 26.5 ng/g creatinine, P = .04) and 2 weeks (233.8 vs 48.3 ng/g creatinine, P = .006), and lactoferrin at 1 week (3.5 vs 0.9 μg/g creatinine, P = .01) were significantly higher in colostrum group. Urine interleukin-1β level was significantly lower in colostrum group at 2 weeks (55.3 vs 91.8 μg/g creatinine, P = .01). Salivary transforming growth factor-β1 (39.2 vs 69.7 μg/mL, P = .03) and interleukin-8 (1.2 vs 4.9 ng/mL, P = .04) were significantly lower at 2 weeks in colostrum group. A significant reduction in the incidence of clinical sepsis was noted in colostrum group (50% vs 92%, P = .003).

CONCLUSIONS

This study suggests that oropharyngeal administration of colostrum may decrease clinical sepsis, inhibit secretion of pro-inflammatory cytokines, and increase levels of circulating immune-protective factors in extremely premature infants. Larger studies to confirm these findings are warranted.

Oropharyngeal administration of mother's milk to prevent necrotizing enterocolitis in extremely low-birth-weight infants: theoretical perspectives

The oropharyngeal administration of mother's milk-placing drops of milk onto the infant's oral mucosa-may serve as a preventative strategy against necrotizing enterocolitis (NEC) for extremely low-birth-weight (ELBW: birth weight <1000 g) infants. Necrotizing enterocolitis is a devastating gastrointestinal disorder which is associated with significant mortality for ELBW infants. Survivors are at risk for costly and handicapping morbidities, including severe neurological impairment. The oropharyngeal administration of mother's milk to ELBW infants may serve to expose the infant's oropharynx to protective (immune and trophic) biofactors (also present in amniotic fluid) and may protect the infant against NEC. Emerging evidence suggests that this intervention may have many benefits for extremely premature infants including protection against bacteremia, NEC, and ventilator-associated pneumonia, an earlier attainment of full enteral feeds, enhanced maturation of oral feeding skills, improved growth, and enhanced breast-feeding outcomes. While more research is needed to definitively establish safety and efficacy of this intervention, this article will examine biological plausibility and will describe the theoretical mechanisms of protection against NEC for ELBW infants who receive this intervention. Nurses play a key role in advancing the science and practice of this intervention. Future directions for research and implications for nursing practice will also be presented.

Stooling pattern and early nutritional exposures associated with necrotizing enterocolitis in premature infants

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency affecting premature infants. A better understanding of the clinical signs and symptoms associated with the disease may result in an improved ability to more effectively intervene in patient care. One of the clinical signs that have not been fully explored is the stooling pattern of preterm infants. This retrospective case-control study included 258 premature infants born prior to 29 weeks of gestation: 129 infants with NEC and 129 gestational age-matched controls. Data were collected from the medical record for the first 28 postnatal days. The relationships between the stooling pattern of premature infants and NEC were assessed via nonparametric techniques and linear mixed models. We identified few differences in the stooling pattern among infants with NEC and their unaffected counterparts. During the first week following birth, infants with NEC passed stool more frequently than controls. However, we found that these infants were taking nothing by mouth for fewer days in the first week following birth compared with controls. We also found that infants who developed NEC were fed smaller proportions of breast milk than healthy controls. Aberrant gut motility has been associated with prematurity and inflammatory bowel disease. However, our analyses did not identify any major differences in the stooling pattern among NEC case patients and controls. While further analyses may be needed, clinical suspicion for NEC should not be overwhelmingly influenced by the stooling pattern observed during the early neonatal period.

Transforming growth factor-β2 and endotoxin interact to regulate homeostasis via interleukin-8 levels in the immature intestine

A balance between pro- and anti-inflammatory signals from milk and microbiota controls intestinal homeostasis just after birth, and an optimal balance is particularly important for preterm neonates that are sensitive to necrotizing enterocolitis (NEC). We suggest that the intestinal cytokine IL-8 plays an important role and hypothesize that transforming growth factor-β2 (TGF-β2) acts in synergy with bacterial lipopolysaccharide (LPS) to control IL-8 levels, thereby supporting intestinal homeostasis. Preterm pigs were fed colostrum (containing TGF-β2) or infant formula (IF) with or without antibiotics (COLOS, n = 27; ANTI, n = 11; IF, n = 40). Intestinal IL-8 levels and NEC incidence were much higher in IF than in COLOS and ANTI pigs (P < 0.001), but IL-8 levels did not correlate with NEC severity. Intestinal TGF-β2 levels were high in COLOS but low in IF and ANTI pigs. Based on these observations, the interplay among IL-8, TGF-β2, and LPS was investigated in a porcine intestinal epithelial cell line. TGF-β2 attenuated LPS-induced IL-6, IL-1β, and TNF-α release by reducing early ERK activation, whereas IL-8 secretion was synergistically induced by LPS and TGF-β2 via NF-κB. The TGF-β2/LPS-induced IL-8 levels stimulated cell proliferation and migration following epithelial injury, without continuous NF-κB activation and cyclooxygenase-2 expression. We suggest that a combined TGF-β2-LPS induction of IL-8 stimulates epithelial repair just after birth when the intestine is first exposed to colonizing bacteria and TGF-β2-containing milk. Moderate IL-8 levels may act to control intestinal inflammation, whereas excessive IL-8 production may enhance the damaging proinflammatory cascade leading to NEC.

Invariant natural killer T cells developing in the human fetus accumulate and mature in the small intestine

Invariant natural killer T (iNKT) cells are CD1d-restricted immunoregulatory lymphocytes that share characteristics of both the innate and adaptive immune systems. Although it has been reported that iNKT cells are present in the human fetal thymus, it is currently unknown how they distribute, differentiate, and function in fetal peripheral lymphoid and non-lymphoid organs. Here, we show that functional human fetal iNKT cells develop and differentiate in a tissue-specific manner during the second trimester. Fetal iNKT cells accumulated in the small intestine, where they gained a mature phenotype and mounted robust interferon (IFN)-γ responses. In contrast, iNKT cells in the spleen and mesenteric lymph nodes were less frequently detected, less differentiated, mounted poor IFN-γ responses, but proliferated vigorously upon stimulation with α-galactosylceramide. These data demonstrate that fetal iNKT cells can differentiate and acquire potent effector functions in utero before the establishment of the commensal microflora.

Gene expression profiling of bovine mammary gland epithelial cells stimulated with lipoteichoic acid plus peptidoglycan from Staphylococcus aureus

A Gram-positive bacterium, Staphylococcus aureus is known to be one of the major pathogenic bacteria responsible for causing bovine mastitis. Among the various cell wall components of S. aureus, lipoteichoic acid (LTA) and peptidoglycan (PGN) are closely associated with inflammatory responses. However, the role of LTA and PGN derived from S. aureus in bovine mastitis has not been clearly elucidated. In this study, we characterized the gene expression profile of a bovine mammary gland epithelial cell line, MAC-T cells, in the presence of LTA and PGN from S. aureus. LTA plus PGN, but not LTA or PGN alone, activated MAC-T cells. The analysis of transcriptional profiles using an Affymetrix genechip microarray showed that stimulation with LTA plus PGN produced a total of 2019 (fold change >1.2) differentially expressed genes (DEGs), with 801 up-regulated genes and 1218 down-regulated genes. Of the up-regulated genes, 14 inflammatory mediator-related DEGs, 22 intra-cellular signaling molecule-related DEGs, and 15 transcription factor-related DEGs were observed, whereas among the down-regulated DEGs 17 inflammation-related DEGs were found. The microarray results were confirmed using real-time RT-PCR of 18 genes with substantial changes in expression (9 each from the up-regulated and down-regulated DEGs). These results provide a comprehensive analysis of gene-expression profiles elicited by S. aureus LTA and PGN in MAC-T cells, contributing to an understanding of the pathogenesis for S. aureus-induced bovine mastitis.

TGF-β2, a protective intestinal cytokine, is abundant in maternal human milk and human-derived fortifiers but not in donor human milk

OBJECTIVE

This study compared cytokines (in particular transforming growth factor [TGF]-β2) and lactoferrin in maternal human milk (MHM), human-derived milk fortifier (HDMF), and donor human milk (DHM).

MATERIALS AND METHODS

MHM was randomly collected from breastfeeding mothers who had no infectious illness at the time of milk expression. HDMF and DHM were products derived from human milk processed by Holder pasteurization. MHM samples were collected at different times (early/late) and gestations (preterm/term). Lactoferrin was analyzed by western blotting, and cytokines were quantified using commercial enzyme-linked immunosorbent assays. Significance was determined using analysis of variance.

RESULTS

In the 164 samples analyzed, TGF-β2 concentrations in HDMF and preterm MHM (at all collection times) were fivefold higher than in DHM (p<0.05). Early preterm MHM had levels of interleukin (IL)-10 and IL-18, 11-fold higher than DHM (p<0.05). IL-6 in DHM was 0.3% of the content found in MHM. IL-18 was fourfold higher in early MHM versus late MHM regardless of gestational age (p<0.05). Lactoferrin concentration in DHM was 6% of that found in MHM.

CONCLUSIONS

Pasteurization decreases concentrations of most cytokines and lactoferrin in DHM. TGF-β2, a protective intestinal cytokine, has comparable concentrations in HDMF to MHM despite pasteurization.

Effects of bovine lactoferrin on the immature porcine intestine

Bioactive milk proteins may be important in protecting preterm infants from developing inflammation and necrotising enterocolitis (NEC). A preterm pig model was used to investigate the protective effects of enteral bovine lactoferrin (bLF) against NEC development and inflammation. Caesarean-delivered preterm pigs were fed parenteral and minimal enteral nutrition for the first 2 d followed by 2 d of total enteral nutrition before euthanasia. Pigs were stratified into two groups and fed with either a control formula (CON, n 15) or a 10 g/l of bLF-enriched formula (LF, n 13). NEC incidence, gut functions and inflammatory cytokines were analysed. NEC incidence and nutrient absorption were similar between the two groups. In pigs that developed NEC, disease outcome was more severe in the colon accompanied by increased intestinal permeability in LF pigs. In contrary, the LF pigs had a lowered IL-1β level in the proximal small intestine. Dose-dependent effects of bLF on cell proliferation, intracellular signalling and cytokine secretion were tested in porcine intestinal epithelial cells (PsIc1) in vitro. Low doses (0·1-1 g/l) increased cell proliferation via extracellular signal-regulated kinase (ERK), limited IL-8 secretion and prevented NF-κB and hypoxia-inducible factor-1α (HIF-1α) activation, suggesting anti-inflammatory effects. In contrast, at a higher dose (10 g/l), bLF exerted adverse effects by reducing cell proliferation, stimulating IL-8 release, inhibiting ERK activation and up-regulating NF-κB and HIF-1α activation. Overall, at a dose of 10 g/l, bLF exacerbated disease severity in pigs that developed NEC, while the in vitro studies indicated the positive effects of bLF at low doses (0·1-1 g/l). Supplementation of infant formulas with bLF should therefore be optimised carefully.

Preterm human milk contains a large pool of latent TGF-β, which can be activated by exogenous neuraminidase

Human milk contains substantial amounts of transforming growth factor (TGF)-β, particularly the isoform TGF-β2. We previously showed in preclinical models that enterally administered TGF-β2 can protect against necrotizing enterocolitis (NEC), an inflammatory bowel necrosis of premature infants. In this study we hypothesized that premature infants remain at higher risk of NEC than full-term infants, even when they receive their own mother's milk, because preterm human milk contains less bioactive TGF-β than full-term milk. Our objective was to compare TGF-β bioactivity in preterm vs. full-term milk and identify factors that activate milk-borne TGF-β. Mothers who delivered between 23 0/7 and 31 6/7 wk or at ≥37 wk of gestation provided milk samples at serial time points. TGF-β bioactivity and NF-κB signaling were measured using specific reporter cells and in murine intestinal tissue explants. TGF-β1, TGF-β2, TGF-β3, and various TGF-β activators were measured by real-time PCR, enzyme immunoassays, or established enzymatic activity assays. Preterm human milk showed minimal TGF-β bioactivity in the native state but contained a large pool of latent TGF-β. TGF-β2 was the predominant isoform of TGF-β in preterm milk. Using a combination of several in vitro and ex vivo models, we show that neuraminidase is a key regulator of TGF-β bioactivity in human milk. Finally, we show that addition of bacterial neuraminidase to preterm human milk increased TGF-β bioactivity. Preterm milk contains large quantities of TGF-β, but most of it is in an inactive state. Addition of neuraminidase can increase TGF-β bioactivity in preterm milk and enhance its anti-inflammatory effects.

Immune factors in breast milk and the development of atopic disease

Breast-feeding provides protection against infections and contains numerous factors that modulate and promote the development of the infant immune system. These factors include secretory IgA, antimicrobial proteins like CD14, cytokines, and fatty acids. Studies examining the role of breast-feeding in the development of allergic disease in infants demonstrate potentially protective as well as neutral or nonprotective effects, likely due to the heterogeneity in their study design. In this overview, we explore the potential role of immune factors in the breast milk, as well as selected probiotics, in the development of allergy.

Maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of eczema in the infant

BACKGROUND

Probiotics have shown promising potential in reducing the risk of eczema in infants. Optimal probiotic intervention regimen remains to be determined.

OBJECTIVE

We investigated whether maternal probiotic supplementation during pregnancy and breast-feeding reduces the risk of developing eczema in high-risk infants.

METHODS

This was a parallel, double-blind placebo-controlled trial of 241 mother-infant pairs. Mothers with allergic disease and atopic sensitization were randomly assigned to receive (1) Lactobacillus rhamnosus LPR and Bifidobacterium longum BL999 (LPR+BL999), (2) L paracasei ST11 and B longum BL999 (ST11+BL999), or (3) placebo, beginning 2 months before delivery and during the first 2 months of breast-feeding. The infants were followed until the age of 24 months. Skin prick tests were performed at the ages of 6, 12, and 24 months.

RESULTS

Altogether 205 infants completed the follow-up and were included in the analyses. The risk of developing eczema during the first 24 months of life was significantly reduced in infants of mothers receiving LPR+BL999 (odds ratio [OR], 0.17; 95% CI, 0.08-0.35; P < .001) and ST11+BL999 (OR, 0.16; 95% CI, 0.08-0.35; P < .001). The respective ORs for chronically persistent eczema were 0.30 (95% CI, 0.12-0.80; P = .016) and 0.17 (95% CI, 0.05-0.56; P = .003). Probiotics had no effect on the risk of atopic sensitization in the infants. No adverse effects were related to the use of probiotics.

CONCLUSION

Prevention regimen with specific probiotics administered to the pregnant and breast-feeding mother, that is, prenatally and postnatally, is safe and effective in reducing the risk of eczema in infants with allergic mothers positive for skin prick test.

Microbial contact during pregnancy, intestinal colonization and human disease

Interaction with colonizing intestinal bacteria is essential for healthy intestinal and immunological development in infancy. Advances in understanding early host-microbe interactions indicate that this early microbial programming begins in utero and is substantially modulated by mode of birth, perinatal antibiotics and breastfeeding. Furthermore, it has become evident that this stepwise microbial colonization process, as well as immune and metabolic programming by the microbiota, might have a long-lasting influence on the risk of not only gastrointestinal disease, but also allergic, autoimmune and metabolic disease, in later life. Modulating early host-microbe interaction by maternal probiotic intervention during pregnancy and breastfeeding offers a promising novel tool to reduce the risk of disease. In this Review, we describe the current body of knowledge regarding perinatal microbial contact, initial intestinal colonization and its association with human disease, as well as means of modulating early host-microbe interaction to reduce the risk of disease in the child.

TGF-β2 induces maturation of immature human intestinal epithelial cells and inhibits inflammatory cytokine responses induced via the NF-κB pathway

OBJECTIVES

Breast milk transforming growth factor (TGF)-β2 is associated with healthy immune maturation and reduced risk of immune-mediated disease in infants. We sought to investigate whether conditioning with TGF-β2 may result in a more mature immune responder phenotype in immature human intestinal epithelial cells (IECs).

METHODS

Primary human fetal IECs (hFIECs) and the human fetal small intestinal epithelial cell line (H4 cells) were conditioned with breast milk levels of TGF-β2, and an inflammatory response was subsequently induced. Inflammatory cytokine secretion and mRNA expression were measured by enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction, respectively. Alterations in activation of inflammatory signaling pathways were detected from IECs by immunoblotting and immunofluorescence. The effects of TGF-β2 conditioning on gene expression patterns in hFIECs were assessed by cDNA microarray analysis and quantitative PCR.

RESULTS

Conditioning with TGF-β2 significantly attenuated subsequent interleukin (IL)-1β-, TNF-α-, and poly I:C-induced IL-8 and IL-6 responses in immature human IECs. Conditioning with TGF-β2 inhibited IL-1β-induced IκB-α degradation and NF-κB p65 nuclear translocation, which may partially result from TGF-β2-induced changes in the expression of genes in the NF-κB signaling pathway detected by cDNA microarray and qPCR.

CONCLUSIONS

Conditioning with TGF-β2 attenuates the subsequent inflammatory cytokine response in immature human IECs by inhibiting signaling in the NF-κB pathway. The immunomodulatory potential of breast milk may in part be mediated by TGF-β2, which may provide a novel means of supporting intestinal immune maturation in neonates.

Glycosaminoglycan content in term and preterm milk during the first month of lactation

BACKGROUND

In a recent study, we performed a complete structural characterization of glycosaminoglycans (GAGs) in human mature milk. However, no data are available on the total content of GAGs in human milk from healthy mothers having delivered term or preterm newborns.

OBJECTIVES

In this study, we evaluated the total content of GAGs in pooled milk from healthy mothers having delivered term or preterm newborns during the first month of lactation.

METHODS

Highly specific and sensitive analytical approaches were used to quantify human milk total GAGs.

RESULTS

Highest GAG values are present at day 4 (9.3 and 3.8 g/l in preterm and term milk, respectively), followed by a progressive decrease up to day 30 (4.3 and 0.4 g/l). The more remarkable differences are related to the first phases of lactation in which a strong decrease in GAGs was observed between days 4 and 10 (about -73% in term and -50% in preterm newborns).

CONCLUSIONS

During the first month of lactation, the absolute amount of polysaccharides was constantly and significantly higher in preterm than in term milk, with a similar behavior in the decrease. These data further indicate that human milk GAGs may have an active role in protecting newborns during the first phases of lactation.

Prematurity does not markedly affect intestinal sensitivity to endotoxins and feeding in pigs

Preterm neonates show enhanced sensitivity to nutrient maldigestion and bacteria-mediated gut inflammatory disorders, such as necrotising enterocolitis (NEC). We hypothesised that preterm birth increases the sensitivity of intestinal nutrient absorption to endotoxins and that feeding after birth reduces this response. Hence, we investigated the postnatal development of nutrient digestive and absorptive capacity in the preterm and term pig intestine, and its responsiveness to endotoxins. Pigs were delivered by caesarean section at preterm (n 20) or term (n 17) gestation, and the small intestine was collected at birth or after 2 d of colostrum feeding, followed by ex vivo stimulation with lipopolysaccharide endotoxins and mixed gut contents collected from pigs with NEC. Brush border enzyme activities were reduced in newborn preterm v. term pigs (39–45 % reduction, P < 0·05), but normalised after 2 d of feeding. Ex vivo leucine and glucose uptake increased with prenatal age. Bacterial stimulation reduced the nutrient uptake similarly at birth and after 2 d in preterm and term pigs (23–41 % reduction, P < 0·05), whereas IL-6 and TNF-α expression was stimulated only at birth. Toll-like receptor-4 expression increased markedly at day 2 for preterm and term pigs (22–33-fold, P < 0·05) but with much lower expression levels in newborn preterm pigs (approximately 95 %, P < 0·01). In conclusion, digestive and absorptive functions mature in the prenatal period, but are similarly affected by postnatal feeding and bacterial exposure in both preterm and term pigs. Nutrient maldigestion may contribute to NEC development, while a prematurity-related hyper-responsiveness to endotoxins could be less important, at least in pigs.