Cytokines in human milk: properties and potential effects upon the mammary gland and the neonate

The Relationship Between Breast Milk Components and the Infant Gut Microbiota

The assembly of the newborn's gut microbiota during the first months of life is an orchestrated process resulting in specialized microbial ecosystems in the different gut compartments. This process is highly dependent upon environmental factors, and many evidences suggest that early bacterial gut colonization has long-term consequences on host digestive and immune homeostasis but also metabolism and behavior. The early life period is therefore a "window of opportunity" to program health through microbiota modulation. However, the implementation of this promising strategy requires an in-depth understanding of the mechanisms governing gut microbiota assembly. Breastfeeding has been associated with a healthy microbiota in infants. Human milk is a complex food matrix, with numerous components that potentially influence the infant microbiota composition, either by enhancing specific bacteria growth or by limiting the growth of others. The objective of this review is to describe human milk composition and to discuss the established or purported roles of human milk components upon gut microbiota establishment. Finally, the impact of maternal diet on human milk composition is reviewed to assess how maternal diet could be a simple and efficient approach to shape the infant gut microbiota.

Lactoferrin and Immunoglobulin Concentrations in Milk of Gestational Diabetic Mothers

Gestational diabetes mellitus (GDM) is associated with an increased risk of having a high-care newborn and has an impact on maternal wellbeing. This study aimed to assess the effect of GDM on the lactoferrin (LF), secretory immunoglobulin A (SIgA), immunoglobulin G (IgG), and immunoglobulin M (IgM) concentrations in early colostrum, colostrum, and transitional milk samples of hyperglycemic (n = 53) and normoglycemic (n = 49) mothers using enzyme-linked immunosorbent assay (ELISA). The concentrations of milk lactoferrin and SIgA, but not IgG and IgM, from hyperglycemic and normoglycemic mothers, showed a similar negative correlation with lactation from the first to the fifteenth day. Apart from early colostral IgG, there were no differences in concentrations of LF and immunoglobulins in milk from hyperglycemic and normoglycemic mothers. For hyperglycemia compensated by diet (GDM G1) or insulin treatment (GDM G2), slight differences were seen for LF and IgG, but not for SIgA and IgM, during an early stage of lactation only. Early colostral IgG and colostral LF of insulin-treated mothers were higher (10.01 ± 4.48 mg/L and 11.50 ± 0.58 g/L, respectively) than for diet-control diabetic mothers (7.65 ± 5.67 mg/L and 8.05 ± 1.38 g/L, respectively). GDM of mothers does not have a significant impact on immunological quality of early milk.

Docosahexaenoic Acid (DHA, C22:6, ω-3) Composition of Milk and Mammary Gland Tissues of Lactating Mother Rats Is Severely Affected by Lead (Pb) Exposure

Docosahexaenoic acid (DHA, C22:6, ω-3), an ω-3 polyunsaturated fatty acid (PUFA), is critical for brain growth, development, and cognitive ability. It is consumed by offspring via milk during lactation. However, the toxic heavy metal lead (Pb) readily passes into the mammary glands of mother animals and then to offspring through milk. Here, we investigated whether DHA composition of milk and mammary gland tissues is affected by Pb exposure. Mother rats were exposed to Pb via drinking water (0.1%). The fatty acid profile and levels of reduced glutathione (GSH), lipid peroxide (LPO), and pro-inflammatory TNF-α in milk and mammary tissues were measured. Levels of DHA and antioxidant GSH decreased (P < 0.05), while LPO and TNF-α levels increased (P < 0.05) both in milk and mammary tissues. Our results suggest that toxic Pb exposure can upset the level of milk DHA, which may affect brain growth and development, and hence cognitive ability in adulthood and later life.

Human Cytomegalovirus (HCMV) Reactivation in the Mammary Gland Induces a Proinflammatory Cytokine Shift in Breast Milk

A locally restricted human cytomegalovirus (HCMV) reactivation in the mammary gland commonly occurs in nearly every IgG-seropositive breastfeeding mother. This unique phenomenon can therefore be used to study the reactivation process in an immunocompetent healthy host. Breast milk contains a variety of immunoactive compounds, including immune cells, antibodies, growth factors, and cytokines supporting the newborn’s immature immune system. To characterize the impact of HCMV reactivation on breast milk cytokines, we analyzed longitudinal breast milk samples of four IgG-seropositive and three IgG-seronegative mothers of preterm infants using Proximity Extension Assay (PEA) technology (Olink Proteomics, Uppsala, Sweden). Cytokine profiling revealed elevated cytokine levels in IgG-seropositive mothers’ milk whey. Reactivating mothers showed higher levels of CC-chemokines (MCP-2, CCL19, and CCL20) and CXC-chemokines (IL-8, CXCL9, CXCL10, and CXCL11), such as the proinflammatory cytokine IL-17C, glycoprotein CD5, and TNFSF14. HCMV reactivation seems to influence the cytokine profile in human breast milk. This work could open the door for further studies analyzing distinct relations of the cytokine network as well as phenotypical and functional T cell properties in background of HCMV DNA dynamics in early lactation.

Temporal development of the infant gut microbiome

The majority of organisms that inhabit the human body reside in the gut. Since babies are born with an immature immune system, they depend on a highly synchronized microbial colonization process to ensure the correct microbes are present for optimal immune function and development. In a balanced microbiome, symbiotic and commensal species outcompete pathogens for resources. They also provide a protective barrier against chemical signals and toxic metabolites. In this targeted review we will describe factors that influence the temporal development of the infant microbiome, including the mode of delivery and gestational age at birth, maternal and infant perinatal antibiotic infusions, and feeding method-breastfeeding versus formula feeding. We will close by discussing wider environmental pressures and early intimate contact, particularly between mother and child, as they play a pivotal role in early microbial acquisition and community succession in the infant.

Association of reduced count of interleukin-13-producing cells in breast milk with atopic dermatitis in infancy

Background & objectives

Atopic dermatitis (AD) is one of the most common pathologic conditions of skin in children. The effect of breastfeeding on the risk of AD remains controversial. The aim of this study was to determine the counts of cytokine-producing cells in the mothers' breast milk of infants with and without AD to assess association, if any.

Methods

Breast milk samples (10 ml) were obtained from mothers of 25 infants with AD and of 26 healthy infants as a control group. The number of cytokine-producing cells including interferon-gamma (IFN-γ), tumour necrosis factor-alpha (TNF-α), interleukin-13 (IL-13) and IL-4 in the milk samples was determined using an enzyme-linked immunospot assay technique.

Results

The mean of IL-13-producing cells in milk was significantly lower in mothers of AD-affected infants in comparison with mothers of normal infants (324.91±255.45 vs. 538.93±465.39, P<0.05). There were no significant differences between mothers of infants with and without AD regarding milk count of IFN-γ-, TNF-α- and IL-4-producing cells.

Interpretation & conclusions

Our results showed lower number of IL-13-producing cells in milk of mothers of infants with AD. Therefore, lower count of IL-13-producing cells in mothers' milk may confer a susceptibility to AD. Further studies with a large number of samples need to be done to confirm our findings.

Influence of a Concurrent Exercise Training Program During Pregnancy on Colostrum and Mature Human Milk Inflammatory Markers: Findings From the GESTAFIT Project

BACKGROUND

Although exercise reduces systemic inflammation, information regarding its influence on human milk is scarce or inexistent. Research Aim: The aim of this study was to investigate the influence of an exercise intervention during pregnancy on colostrum and mature human milk inflammatory markers.

METHODS

The authors conducted a pseudorandomized controlled trial. The exercise group followed a concurrent aerobic and strength training, three 60-minutes sessions per week, from the 17th gestational week until delivery. For the specific aims of this study, only women able to produce enough milk were included for data analyses, resulting in 24 exercise and 23 control women. Colostrum and mature human milk proinflammatory and anti-inflammatory cytokines (fractalkine, interleukin [IL]-1β, IL-6, IL-8, IL-10, interferon [IFN]-γ, and tumor necrosis factor [TNF]-α) were measured using Luminex xMAP technology.

RESULTS

The mothers who followed the exercise program had 36% lower IL-8 and 27% lower TNF-α concentrations in their colostrum than those in the control group ( p < .05 and p < .01, respectively). The colostrum from mothers who followed the exercise program also presented borderline significant 22% lower IL-6 ( p < .100). The mature milk from mothers who followed the exercise program had 30% greater fractalkine ( p = .05) and borderline significant 20% higher IL-10 ( p = .100). The exercise intervention did not affect IFN-γ concentrations.

CONCLUSIONS

This concurrent exercise program promoted a less proinflammatory profile in human milk, especially in colostrum. Moreover, it might increase mature human milk fractalkine, which could induce a greater neurodevelopment and neuroprotection in the newborn. This trial was registered at ClinicalTrials.gov (NCT02582567) on October 20, 2015.

Pasteurization Preserves IL-8 in Human Milk

Background: Pasteurized donor human milk is an alternative feeding when mothers' own milk is not available for premature infants. The effects of pasteurization on the host defense properties of human milk are unclear. We investigated the effects of Holder pasteurization on concentrations of anti-inflammatory and pro-inflammatory cytokines in human milk. Objective: To compare concentrations of anti-inflammatory and pro-inflammatory cytokines before and after pasteurization of donor human milk. Study Design: A single milk sample was obtained from each of 24 mothers of premature infants in the neonatal intensive care unit by electric breast pump and was stored at -80°C. At the time of pasteurization, milk samples were thawed and divided into two aliquots. The first aliquot was re-stored at -80°C and the second aliquot was heat-treated at 62.5°C for 30 min and then re-stored at -80°C. At the time of batch cytokine analyses samples were thawed rapidly. Results: Most cytokine concentrations declined following pasteurization. The most prevalent cytokine, IL-8, was preserved (89%) following pasteurization. There were no relationships between gestational age, postnatal age of milk collection, duration of milk storage, and the concentrations cytokines. Conclusion: In contrast to most cytokines after pasteurization, IL-8 is preserved or liberated from another compartment. The maintenance of IL-8 in human milk after pasteurization and the loss of anti-inflammatory cytokines following pasteurization, suggests that the effects of inflammatory activity in pasteurized human milk should be evaluated. These data may account, in part, for the lesser protective effect on the host of pasteurized donor human milk compared with mother's own milk.

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 Effect of Holder Pasteurization on Activin A Levels in Human Milk

INTRODUCTION

There is evidence that mother's own milk is the best nutrient in terms of multiorgan protection and infection prevention. However, when maternal milk is scarce, the solution can be represented by donor milk (DM), which requires specific storage procedures such as Holder Pasteurization (HoP). HoP is not free from side effects since it is widely known that it causes qualitative/quantitative changes in milk composition, particularly in the protein content. Therefore, the aim of this study is to investigate the effects of HoP on Activin A, a neurobiomarker known to play an important role in the development and protection of the central nervous system.

METHODS

In 24 mothers who delivered preterm (n = 12) and term (n = 12) healthy newborns, we conducted a pretest/test study where the milk donors acted as their own controls. Each sample was divided into two parts: the first was frozen at -80°C (Group 1); the second was Holder-pasteurized before freezing at -80°C (Group 2). Activin A was quantified using an ELISA test.

RESULTS

Activin A was detected in all samples. There were no significant differences (p > 0.05) between the two groups, also when the analysis was stratified for gestational age at delivery and milk maturation degree (p > 0.05, for both).

CONCLUSION

The present findings on the absence of any side effects of HoP on the milk concentration of Activin A offer additional support to the efficacy of HoP in DM storage. Our data open up to further investigations on neurobiomarkers' assessment in human milk and their preanalytical stability according to storage procedures.

Longitudinal Study of Cytokine Expression, Lipid Profile and Neuronal Growth Factors in Human Breast Milk from Term and Preterm Deliveries

Breast milk (BM) is considered as a reference for infant nutrition. The role of bioactive components, such as cytokines, hormones, growth factors (GFs) and fatty acids (FAs) is poorly known, but they might be implicated in immune response development. The aim of this study was to identify the lipid profile and the spectrum of cytokines and neuronal GF in BM samples and analyse the influence of gestational age and lactation time on these components. This study used a longitudinal prospective method for the characterization of cytokines, FAs and GFs global profiles in 120 BM samples from 40 healthy mothers (20 preterm and 20 term) collected as colostrum, transitional and mature milk. The cytokines were analysed by protein array (Ray Bio® Human Cytokine Array G6. Ray Biotech, Inc. Norcross, GA, USA) and the FAs were analysed by gas chromatography. The FA profile was similar between the term and the preterm BM samples. Omega-3-α-linoleic and docosahexaenoic acid (DHA) and omega-6-linoleic acid were the most abundant in the term and preterm samples during lactation. Omega-3 ETA and omega-3 EPA we observed exclusively in the preterm samples. The cytokine profile showed a different trend based on gestational age. A significantly higher expression of neurotrophic factors was found in the mature preterm milk samples as compared to the mature term samples. Our study is the first to identify the influence and interactions of perinatal factors on cytokine, GFs and FAs in human milk.

Expression of acute phase proteins and inflammatory cytokines in mouse mammary gland followingStaphylococcus aureuschallenge and in response to milk accumulation

We used a mouse model of pathogenic (Staphylococcus aureus) and non-pathogenic (teat sealing) mammary inflammation to investigate mRNA expression of several inflammatory cytokines and acute phase proteins (APP) in mammary tissue and liver, and the appearance of some of these factors in plasma and milk. The expression levels of IL1β and TNFα were markedly up-regulated inStaph. aureus-inoculated mammary tissue at 72 h, whilst IL6 was up-regulated to a lesser extent in a way which was not confined to the inoculated glands. APP expression was up-regulated at 48 and 72 h in bothStaph. aureus-inoculated and teat-sealedmammaryglands. These differences between cytokine and APP expression provide additional support for the contention that APPs are produced within the mammary tissue itself during inflammation, rather than in associated immune cells. We propose that measurement of cytokines and APP in combination might provide a tool for diagnostic discrimination between mastitis caused by pathogenic invasion and milk accumulation, and hence allow for better targeting of antibiotic therapy. In comparison with mammary expression, expression of cytokines in liver tissue was up-regulated to a similar or lesser extent, whilst expression of APP was up-regulated to a much greater extent. The first appearance of increased cytokine and APP concentrations in plasma and of milk amyloid A (MAA) in milk occurred in advance of the measurable up-regulation of expression, hence their origin cannot be stated with certainty.

Mammary inflammation around parturition appeared to be attenuated by consumption of fish oil rich in n-3 polyunsaturated fatty acids

Background

Mastitis endangers the health of domestic animals and humans, and may cause problems concerning food safety. It is documented that n-3 polyunsaturated fatty acids (PUFA) play significant roles in attenuating saturated fatty acids (SFA)-induced inflammation. This study was therefore conducted to determine whether mammary inflammation could be affected by consumption of diets rich in n-3 PUFA.

Methods

Forty-eight rats after mating began to receive diets supplemented with 5% fish oil (FO) or 7% soybean oil (SO). Blood and mammary tissue samples (n = 6) at day 0 and 14 of gestation and day 3 postpartum were collected 9 hours after intramammary infusion of saline or lipopolysaccharide (LPS) to determine free fatty acids (FFA) concentration and FA composition in plasma and inflammation mediators in mammary tissues.

Results

At day 14 of gestation and day 3 postpartum, the FO-fed rats had lower plasma concentrations of C18:2n6, C20:4n6, total n-6 PUFA and SFA, and higher plasma concentrations of C20:5n3 and total n-3 PUFA than the SO-fed rats. Plasma C22:6n3 concentration was also higher in the FO-fed than in the SO-fed rats at day 3 postpartum. Compared with the SO-fed rats, the FO-fed rats had lower mammary mRNA abundance of xanthine oxidoreductase (XOR) and protein level of tumor necrosis factor (TNF)-α, but had higher mammary mRNA abundances of interleukin (IL)-10 and peroxisome proliferator-activated receptor (PPAR)-γ at day 14 of gestation. Following LPS infusion at day 3 postpartum, the SO-fed rats had increased plasma concentrations of FFA, C18:1n9, C18:3n3, C18:2n6 and total n-6 PUFA, higher mammary mRNA abundances of IL-1β, TNF-α and XOR but lower mammary mRNA abundance of IL-10 than the FO-fed rats.

Conclusions

Mammary inflammation around parturition appeared to be attenuated by consumption of a diet rich in n-3 PUFA, which was associated with up-regulated expression of IL-10 and PPAR-γ.

Presence of IL-9 in paired samples of human colostrum and transitional milk

BACKGROUND

Human colostrum and breast milk are known to contain high levels of cytokines, cytokine receptors, and chemokines.

OBJECTIVE

To investigate the presence and compare levels of soluble cytokines in paired samples of human colostrum and milk.

METHODS

Levels of 27 cytokines were measured in 9 paired samples of human colostrum (day 2 after delivery) and breast milk (day 4 or 5 after delivery) by using multiplex technology.

RESULTS

The majority of cytokines and chemokines investigated have been previously described in colostrum and/or breast milk. For the first time, we describe the presence of IL-9 in both human colostrum and milk. Of the 27 cytokines investigated, only IL-5 was absent in both colostrum and milk, whereas IL-1β, IL-2, IL-4, IL-15, IL-17, and MIP-1α were present in colostrum, but not in breast milk. In general, colostrum contained higher concentrations of cytokines with respect to human milk.

CONCLUSION

Our data confirm and expand previous studies showing that human colostrum and breast milk are rich in cytokines and chemokines, including IL-9, which might contribute to the development of the immune system of the newborn.

Maternal protein deficiency during a gastrointestinal nematode infection alters developmental profile of lymphocyte populations and selected cytokines in neonatal mice

Neonatal immune development begins in pregnancy and continues into lactation and may be affected by maternal diet. We investigated the possibility that maternal protein deficiency (PD) during a chronic gastrointestinal (GI) nematode infection could impair neonatal immune development. Beginning on d 14 of pregnancy, mice were fed protein-sufficient (PS; 24%) or protein-deficient (PD; 6%) isoenergetic diets and were infected weekly with either 0 (sham) or 100 Heligmosomoides bakeri larvae. Pups were killed on d 2, 7, 14, and d 21 and dams on d 20 of lactation. Lymphoid organs were weighed. Cytokine concentration in maternal and pup serum and in milk from pup stomachs and lymphoid cell populations in pup spleen and thymus were determined using luminex and flow cytometry, respectively. GI nematode infection increased Th2 cytokines (IL-4, IL-5, IL-13), IL-2, IL-10, and eotaxin in serum of dams whereas PD reduced IL-4 and IL-13. The lower IL-13 in PD dams was associated with increased fecal egg output and worm burdens. Maternal PD increased vascular endothelial growth factor in pup milk and eotaxin in pup serum. Maternal infection increased eotaxin in pup serum. Evidence of impaired neonatal immune development included reduced lymphoid organ mass in pups associated with both maternal infection and PD and increased percentage of T cells and T:B cell ratio in the spleen associated with maternal PD. Findings suggest that increases in specific proinflammatory cytokines as a result of the combination of infection and dietary PD in dams can impair splenic immune development in offspring.

The principal fucosylated oligosaccharides of human milk exhibit prebiotic properties on cultured infant microbiota

Breast-fed infant microbiota is typically rich in bifidobacteria. Herein, major human milk oligosaccharides (HMOS) are assessed for their ability to promote the growth of bifidobacteria and to acidify their environment, key features of prebiotics. During in vitro anaerobic fermentation of infant microbiota, supplementation by HMOS significantly decreased the pH even greater than supplementation by fructooligosaccharide (FOS), a prebiotic positive control. HMOS elevated lactate concentrations, increased the proportion of Bifidobacterium spp. in culture, and through their fermentation into organic acids, decreased the proportion of Escherichia and Clostridium perfringens. Three principal components of HMOS, 2'-fucosyllactose, lactodifucotetraose and 3-fucosyllactose, were consumed in these cultures. These three principal oligosaccharides of human milk were then individually tested as supplements for in vitro growth of four individual representative strains of infant gut microbes. Bifidobacterium longum JCM7007 and B. longum ATCC15697 efficiently consumed oligosaccharides and produced abundant lactate and short-chain fatty acids, resulting in significant pH reduction. The specificity of fermentation differed by microbe species and strain and by oligosaccharide structure. Escherichia coli K12 and C. perfringens did not utilize appreciable fucosylated oligosaccharides, and a typical mixture of organic acid fermentation products inhibited their growth. In summary, 2'-fucosyllactose, lactodifucotetraose, and 3-fucosyllactose, when cultured with B. longum JCM7007 and B. longum ATCC15697, exhibit key characteristics of a prebiotic in vitro. If these bifidobacteria are representative of pioneering or keystone species for human microbiota, fucosylated HMOS could strongly promote colonization and maintenance of a mutualist symbiotic microbiome. Thus, these simple glycans could mediate beneficial effects of human milk on infant health.

Relationship of insulin, glucose, leptin, IL-6 and TNF-α in human breast milk with infant growth and body composition

BACKGROUND

Numerous appetite, growth, obesity-related hormones and inflammatory factors are found in human breast-milk, but there is little evidence on their relationship with infant body composition. OBJECTVIE: The purpose of the present cross-sectional pilot study was to assess the cross-sectional associations of appetite-regulating hormones and growth factors (leptin, insulin and glucose) and inflammatory factors (interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-α)) in human breast-milk with infant size, adiposity, and lean tissue at 1-month of age in healthy term infants.

METHODS

Human breast-milk was collected from nineteen exclusively breast-feeding mothers using one full breast expression between 8:00 and 10:00 a.m. The milk was then mixed, aliquoted, stored at -80°C and then centrifuged to remove the milk fat, prior to analyses using commercially available immunoassay kits; milk analytes were natural log transformed prior to analysis. Infant body composition was assessed using a Lunar iDXA v11-30.062 scanner (Infant whole body analysis enCore 2007 software, GE, Fairfield, CT).

RESULTS

Maternal pre-pregnancy BMI was positively associated with milk leptin concentration (P = 0.0027), and so maternal-BMI-adjusted Spearman correlations were examined between breast-milk analytes and infant growth and body composition variables. As previously reported, greater milk leptin was associated with lower BMIZ (BMI-for-age z-score based on WHO 2006 growth charts; r = -0.54, P = 0.03). Glucose was positively associated with relative weight (r = 0.6, P = 0.01), and both fat and lean mass (0.43-0.44, P < 0.10). Higher concentrations of milk insulin were associated with lower infant weight, relative weight, and lean mass (r = -0.49-0.58, P < 0.06). Higher milk IL-6 was associated with lower relative weight, weight gain, percent fat, and fat mass (r = -0.55-0.70, P < 0.03 for all), while higher TNF-α was associated with lower lean mass (r = -0.58, P = 0.05), but not measures of adiposity.

CONCLUSIONS

These preliminary data suggest for the first time that in the first months of life, breast-milk concentrations of insulin, glucose, IL-6 and TNF-α, in addition to leptin, may be bioactive and differentially influence the accrual of fat and lean body mass.

Paracrine interactions between primary human macrophages and human fibroblasts enhance murine mammary gland humanization in vivo

INTRODUCTION

Macrophages comprise an essential component of the mammary microenvironment necessary for normal gland development. However, there is no viable in vivo model to study their role in normal human breast function. We hypothesized that adding primary human macrophages to the murine mammary gland would enhance and provide a novel approach to examine immune-stromal cell interactions during the humanization process.

METHODS

Primary human macrophages, in the presence or absence of ectopic estrogen stimulation, were used to humanize mouse mammary glands. Mechanisms of enhanced humanization were identified by cytokine/chemokine ELISAs, zymography, western analysis, invasion and proliferation assays; results were confirmed with immunohistological analysis.

RESULTS

The combined treatment of macrophages and estrogen stimulation significantly enhanced the percentage of the total gland humanized and the engraftment/outgrowth success rate. Timecourse analysis revealed the disappearance of the human macrophages by two weeks post-injection, suggesting that the improved overall growth and invasiveness of the fibroblasts provided a larger stromal bed for epithelial cell proliferation and structure formation. Confirming their promotion of fibroblasts humanization, estrogen-stimulated macrophages significantly enhanced fibroblast proliferation and invasion in vitro, as well as significantly increased proliferating cell nuclear antigen (PCNA) positive cells in humanized glands. Cytokine/chemokine ELISAs, zymography and western analyses identified TNFα and MMP9 as potential mechanisms by which estrogen-stimulated macrophages enhanced humanization. Specific inhibitors to TNFα and MMP9 validated the effects of these molecules on fibroblast behavior in vitro, as well as by immunohistochemical analysis of humanized glands for human-specific MMP9 expression. Lastly, glands humanized with macrophages had enhanced engraftment and tumor growth compared to glands humanized with fibroblasts alone.

CONCLUSIONS

Herein, we demonstrate intricate immune and stromal cell paracrine interactions in a humanized in vivo model system. We confirmed our in vivo results with in vitro analyses, highlighting the value of this model to interchangeably substantiate in vitro and in vivo results. It is critical to understand the signaling networks that drive paracrine cell interactions, for tumor cells exploit these signaling mechanisms to support their growth and invasive properties. This report presents a dynamic in vivo model to study primary human immune/fibroblast/epithelial interactions and to advance our knowledge of the stromal-derived signals that promote tumorigenesis.

Associations of prenatal metabolic abnormalities with insulin and adiponectin concentrations in human milk

BACKGROUND

Emerging evidence indicates that metabolic hormones are present in human milk, but, to our knowledge, no studies have investigated the impact of maternal metabolic status assessed during pregnancy on insulin and adiponectin concentrations in milk.

OBJECTIVES

We aimed to investigate the associations of prenatal metabolic abnormalities with insulin and adiponectin in human milk and to compare the concentrations of these hormones in early and mature milk.

DESIGN

Pregnant women aged ≥20 y with intention to breastfeed and without preexisting type 1 or 2 diabetes were recruited. Participants (n = 170) underwent a 3-h oral-glucose-tolerance test at 30 wk (95% CI: 25, 33 wk) gestation and donated early (the first week postpartum) and mature (3 mo postpartum) milk.

RESULTS

Adiponectin and insulin concentrations in early milk were higher than those in mature milk (both P < 0.0001). Prenatal metabolic abnormalities, including higher pregravid BMI (β ± SEE: 0.053 ± 0.014; P = 0.0003) and gravid hyperglycemia (0.218 ± 0.087; P = 0.01), insulin resistance (0.255 ± 0.047; P < 0.0001), lower insulin sensitivity (-0.521 ± 0.108; P < 0.0001), and higher serum adiponectin (0.116 ± 0.029; P < 0.0001), were associated with higher insulin in mature milk after covariate adjustment. Prenatal metabolic measures were not associated with milk adiponectin, but obstetrical measures that included nulliparity (0.171 ± 0.058; P = 0.004), longer duration of gestation (0.546 ± 0.146; P = 0.0002), and unscheduled cesarean delivery (0.387 ± 0.162; P = 0.02) were associated with higher adiponectin in early milk after covariate adjustment, including the time elapsed from delivery to milk collection.

CONCLUSION

Maternal prenatal metabolic abnormalities are associated with high insulin concentrations in mature milk, whereas only obstetrical variables are associated with adiponectin concentrations in early milk.

Human milk and formulae: neurotrophic and new biological factors

Mother milk is widely accepted to be a unique product believed to contain biological factors involved in the regulation of newborn optimal growth including brain when compared to milk-formula milks. In this setting, there is growing evidence that in milk-formula neuro-oxidative stress biomarkers, neurotrophic proteins and calcium binding proteins, known to be involved in a cascade of events leading to brain, cardiac and vascular development/damage, are to date lacking or at a lower concentration than breast milk. Therefore, this review is aimed at offering additional insights to the role in human milk of some selected biomarkers such as: i) neurotrophic factors such as Activin A; ii) Calcium binding protein such as S100B and, iii) heat shock protein known to be involved in oxidative stress response (namely hemeoxygenase-1, HO-1 or Heat shock Protein 32, HSP32).

Breastfeeding and lung function at school age: does maternal asthma modify the effect?

RATIONALE

The evidence for an effect of breastfeeding on lung function is conflicting, in particular whether the effect is modified by maternal asthma.

OBJECTIVES

To explore the association between breastfeeding and school-age lung function.

METHODS

In the Leicestershire Cohort Studies we assessed duration of breastfeeding (not breastfed, ≤3 months, 4-6 months, and >6 months), other exposures, and respiratory symptoms by repeated questionnaires. Post-bronchodilator FVC, FEV(1), peak expiratory flow (PEF), forced midexpiratory flow (FEF(50)), and skin prick tests were measured at age 12 years. We performed multivariable linear regression and tested potential causal pathways (N = 1,458).

MEASUREMENTS AND MAIN RESULTS

In the entire sample, FEF(50) was higher by 130 and 164 ml in children breastfed for 4 to 6 months and longer than 6 months, respectively, compared with those not breastfed (P = 0.048 and 0.041), with larger effects if the mother had asthma. FVC and FEV(1) were associated with breastfeeding only in children of mothers with asthma (P for interaction, 0.018 and 0.008): FVC was increased by 123 and 164 ml for those breastfed 4 to 6 months or longer than 6 months, respectively (P = 0.177 and 0.040) and FEV(1) was increased by 148 and 167 ml, respectively (P = 0.050 and 0.016). Results were unchanged after adjustment for respiratory infections in infancy and asthma and atopy in the child.

CONCLUSIONS

In this cohort, breastfeeding for more than 4 months was associated with increased FEF(50) and, in children of mothers with asthma, with increased FEV(1) and FVC. It seems that the effect is not mediated via avoidance of early infections or atopy but rather through a direct effect on lung growth.

Changes in immunomodulatory constituents of human milk in response to active infection in the nursing infant

INTRODUCTION

To investigate whether immunologic factors in breast milk change in response to nursing infants' infection.

RESULTS

Total CD45 leukocyte count dropped from 5,655 (median and interquartile range: 1,911; 16,871) in the acute phase to 2,122 (672; 6,819) cells/ml milk after recovery with macrophage count decreasing from 1,220 (236; 3,973) to 300 (122; 945) cells/ml. Tumor necrosis factor-α (TNFα) levels decreased from 3.66 ± 1.68 to 2.91 ± 1.51 pg/ml. The decrease in lactoferrin levels was of borderline statistical significance. Such differences were not recorded in samples of the controls. Interleukin-10 levels decreased in the sick infants' breast milk after recovery, but also in the healthy controls, requiring further investigation. Secretory immunoglobulin A levels did not change significantly in the study or control group.

DISCUSSION

During active infection in nursing infants, the total number of white blood cells, specifically the number of macrophages, and TNFα levels increase in their mothers' breast milk. These results may support the dynamic nature of the immune defense provided by breastfeeding sick infants.

METHODS

Breast milk from mothers of 31 infants, up to 3 months of age, who were hospitalized with fever, was sampled during active illness and recovery. Milk from mothers of 20 healthy infants served as controls.

Review of the Relationships Between Maternal Characteristics and Preterm Breastmilk Immune Components

The immune properties of breastmilk are the most effective preventative means of reducing infant mortality through both passive and active immunity. Breastmilk for term infants has been linked to decreased incidence of respiratory and ear infections and gastrointestinal distress. This protection is even more important for the preterm infant. Prematurity is one of the leading causes of infant death in the United States. Hospitalized infant outcomes associated with consumption of breastmilk are shorter length of stay and decreased incidence of nosocomial infections and necrotizing enterocolitis (NEC). The presence of nosocomial infections and necrotizing enterocolitis increases risk of preterm mortality and morbidity as well as healthcare expenditures. However, breastmilk immunological components such as secretory immunoglobulin A, lactoferrin (LFT), and cytokines provide a framework of immunity that, in conjunction with nutritional support, significantly improves neonatal health. The relationship between maternal characteristics and breastmilk immune properties is central to further the understanding of the impact of breastmilk on preterm infant morbidity and mortality. The purpose of this article is to review the numerous immune components in breastmilk, the moderators of the immune components, and the relevance of these components to preterm/infant health. Exploration of the complexity of breastmilk immune components may direct future development of interventions to improve and sustain the immunological benefits of preterm breastmilk.

Impact of maternal metabolic abnormalities in pregnancy on human milk and subsequent infant metabolic development: methodology and design

BACKGROUND

Childhood obesity is on the rise and is a major risk factor for type 2 diabetes later in life. Recent evidence indicates that abnormalities that increase risk for diabetes may be initiated early in infancy. Since the offspring of women with diabetes have an increased long-term risk for obesity and type 2 diabetes, the impact of maternal metabolic abnormalities on early nutrition and infant metabolic trajectories is of considerable interest. Human breast milk, the preferred food during infancy, contains not only nutrients but also an array of bioactive substances including metabolic hormones. Nonetheless, only a few studies have reported concentrations of metabolic hormones in human milk specifically from women with metabolic abnormalities. We aim to investigate the impact of maternal metabolic abnormalities in pregnancy on human milk hormones and subsequently on infant development over the first year of life. The objective of this report is to present the methodology and design of this study.

METHODS/DESIGN

The current investigation is a prospective study conducted within ongoing cohort studies of women and their offspring. Pregnant women attending outpatient obstetrics clinics in Toronto, Canada were recruited. Between April 2009 and July 2010, a total of 216 pregnant women underwent a baseline oral glucose tolerance test and provided medical and lifestyle history. Follow-up visits and telephone interviews are conducted and expected to be completed in October 2011. Upon delivery, infant birth anthropometry measurements and human breast milk samples are collected. At 3 and 12 months postpartum, mothers and infants are invited for follow-up assessments. Interim telephone interviews are conducted during the first year of offspring life to characterize infant feeding and supplementation behaviors.

DISCUSSION

An improved understanding of the link between maternal metabolic abnormalities in pregnancy and early infant nutrition may assist in the development of optimal prevention and intervention strategies and in the protection of nutritionally vulnerable offspring who are at risk for obesity and diabetes later in life.

Novel roles for immune molecules in neural development: implications for neurodevelopmental disorders

Although the brain has classically been considered “immune-privileged”, current research suggests an extensive communication between the immune and nervous systems in both health and disease. Recent studies demonstrate that immune molecules are present at the right place and time to modulate the development and function of the healthy and diseased central nervous system (CNS). Indeed, immune molecules play integral roles in the CNS throughout neural development, including affecting neurogenesis, neuronal migration, axon guidance, synapse formation, activity-dependent refinement of circuits, and synaptic plasticity. Moreover, the roles of individual immune molecules in the nervous system may change over development. This review focuses on the effects of immune molecules on neuronal connections in the mammalian central nervous system – specifically the roles for MHCI and its receptors, complement, and cytokines on the function, refinement, and plasticity of geniculate, cortical and hippocampal synapses, and their relationship to neurodevelopmental disorders. These functions for immune molecules during neural development suggest that they could also mediate pathological responses to chronic elevations of cytokines in neurodevelopmental disorders, including autism spectrum disorders (ASD) and schizophrenia.

Long-term health outcomes and mechanisms associated with breastfeeding

Breastfeeding is superior to formula feeding because it has factors that have long term consequences for early metabolism and disease later in life. In this paper, the scientific evidence in support of why breast milk is beneficial for infants is summarized and the mechanisms in which breastfeeding impacts on disease are explored. Human milk may show a reduced occurrence of disease because mammalian evolution promotes survival, and because of specific factors in milk that promote active stimulation of the infant's immune system and gastrointestinal mucosal maturation decrease the incidence of infection and alter the gut microflora. Bioactive factors, including: hormones, growth factors, colony-stimulating factors and specific nutrients, may have such far-reaching effects on the infant's immune response that normal development depends heavily on its provision. All mothers should be encouraged and supported to continue breastfeeding for 6 months and beyond in order to promote the good health of their infants.

Cytokines in human milk

Epidemiologic studies conducted in the past 30 years to investigate the protective functions of human milk strongly support the notion that breastfeeding prevents infantile infections, particularly those affecting the gastrointestinal and respiratory tracts. However, more recent clinical and experimental observations also suggest that human milk not only provides passive protection, but also can directly modulate the immunological development of the recipient infant. The study of this remarkable defense system in human milk has been difficult because of its biochemical complexity, the small concentration of certain bioactive components, the compartmentalization of some of these agents, the dynamic quantitative and qualitative changes of milk during lactation, and the lack of specific reagents to quantify these agents. However, a host of bioactive substances, including hormones, growth factors, and immunological factors such as cytokines, have been identified in human milk. Cytokines are pluripotent polypeptides that act in autocrine/paracrine fashions by binding to specific cellular receptors. They operate in networks and orchestrate the development and functions of immune system. Several different cytokines and chemokines have been discovered in human milk in the past years, and the list is growing very rapidly. This article will review the current knowledge about the increasingly complex network of chemoattractants, activators, and anti-inflammatory cytokines present in human milk and their potential role in compensating for the developmental delay of the neonate immune system.

The long-term effects of breastfeeding on asthma and atopic disease

In this review, the primary objective is to assess the evidence of whether breastfeeding protects against asthma and atopic disease for the long-term (long-term is defined here as >5 years of age). Two main types of observational epidemiological studies have been used to test this hypothesis. These are cohort studies of random samples of children and cohort studies of children with a family history of asthma or atopy. In each study type, exposure and outcome data are collected either prospectively or retrospectively. The 12 criteria for assessing the adequate measurement of exposure, outcome and statistics of cohort studies in this context are given in Table 17-1.

Loss of caveolin-3 induces a lactogenic microenvironment that is protective against mammary tumor formation

Here, we show that functional loss of a single gene is sufficient to confer constitutive milk protein production and protection against mammary tumor formation. Caveolin-3 (Cav-3), a muscle-specific caveolin-related gene, is highly expressed in muscle cells. We demonstrate that Cav-3 is also expressed in myoepithelial cells within the mammary gland. To determine whether genetic ablation of Cav-3 expression affects adult mammary gland development, we studied the phenotype(s) of Cav-3(-/-)-null mice. Interestingly, Cav-3(-/-) virgin mammary glands developed lobulo-alveolar hyperplasia, akin to the changes normally observed during pregnancy and lactation. Genome-wide expression profiling revealed up-regulation of gene transcripts associated with pregnancy/lactation, mammary stem cells, and human breast cancers, consistent with a constitutive lactogenic phenotype. Expression levels of three key transcriptional regulators of lactation, namely Elf5, Stat5a, and c-Myc, were also significantly elevated. Experiments with pregnant mice directly showed that Cav-3(-/-) mice underwent precocious lactation. Finally, using orthotopic tumor cell implantation, we demonstrated that virgin Cav-3(-/-) mice were dramatically protected against mammary tumor formation. Thus, Cav-3(-/-) mice are a novel preclinical model to study the protective effects of a lactogenic microenvironment on mammary tumor onset and progression. Our current studies have broad implications for using the lactogenic microenvironment as a paradigm to discover new therapies for the prevention and/or treatment of human breast cancers.

Trans-epithelial immune cell transfer during suckling modulates delayed-type hypersensitivity in recipients as a function of gender

Introduction

Breast feeding has long term effects on the developing immune system which outlive passive immunization of the neonate. We have investigated the transfer of milk immune cells and examined the result of transfer once the recipients were adult.

Methods

Non-transgenic mouse pups were foster-nursed by green fluorescent protein (GFP) transgenic dams for 3 weeks and the fate of GFP+ cells was followed by FACS analysis, immunohistochemistry and RT-PCR for GFP and appropriate immune cell markers. Pups suckled by non-transgenic dams served as controls.

Results

Despite a preponderance of B cells and macrophages in the stomach contents of the pups, most cells undergoing trans-epithelial migration derived from the 3–4% of milk cells positive for T lymphocyte markers. These cells homed to the spleen and thymus, with maximal accumulation at 3–4 weeks. By sensitizing dams with an antigen which elicits a T cell-mediated delayed-type-hypersensitivity (DTH) response, we determined that nursing by a sensitized dam (compared to a non-sensitized dam) amplified a subsequent DTH response in females and yet suppressed one in males.

Discussion

These results suggest that clinical evaluation weighing the pros and cons of nursing male versus female children by mothers with genetically-linked hypersensitivity diseases, such as celiac disease and eczema, or those in regions of the world with endemic DTH-eliciting diseases, such as tuberculosis, may be warranted.

S100B concentration in colostrums of Burkinabe and Sicilian women

The aim of this study is to determine the S100B concentration in colostrums of 51 Burkinabe and 30 Sicilian women, still living in their countries, and in case of a difference to search for its explanations, considering also ethnic differences.

The concentration of S100B, in colostrums of the first three days from the delivery, was assessed with commercial immunoluminometric assay.

The production of colostrums was significantly higher in Burkinabe women, where the colostrums S100B levels in the first day of lactation showed to be at 24 h higher than those of Sicilian mothers (672.21 ± 256.67 ng/ml vs 309.36 ± 65.28 ng/ml) and progressively decreased reaching the values of Sicilian mothers in the second and third day (204.31 ± 63.25 ng/ml and 199.42 ± 45.28 ng/ml, respectively). Correlation was found between the level of S100B and the length of stage II (duration of expulsive phase of delivery), but the correlation with pain was found only in Burkinabe women.

The S100B level in colostrums of Burkinabe mothers differs from that of Sicilians only in the first day of lactation, and in consideration that Burkinabe women produce more colostrums, their newborns receive, during the first days of life, an higher amount of S100B. The elevated quantity of S100B ingested by Burkinabe newborn in the first days of life could promote the physiological postnatal brain adaptation and maturation in the precarious delivery condition of African infants.

Reduced thymic size and numbers of splenic CD4+ and CD8+ cells in artificially reared mouse pups

The effect of early nutrition on the development of the immune tissue and T cells of mouse pups was examined. Newborn mice were divided into three experimental groups: mother-reared (MR) pups, pups that were fed on a milk substitute from the first day (AR-0), and the third day (AR-2), using a hand-feeding system. The average thymic size of the AR-2 pups was respectively significantly larger and smaller than that of the AR-0 and MR pups. In contrast, the splenic sizes of the AR-0 and AR-2 pups were greater than that of the MR pups. The numbers of CD4+CD8- and CD4-CD8+ cells in the spleen of the MR pups were significantly higher than those in the AR-0 pups. These results indicate that early nutrition affected the sizes of the thymus and spleen and the composition of CD4+CD8- or CD4-CD8+ T cells in the spleen.

Effect of breastfeeding on lung function in childhood and modulation by maternal asthma and atopy

RATIONALE

The protective effect of breastfeeding on early respiratory infections is well established, but its relationship to the development of subsequent asthma remains controversial.

OBJECTIVES

To clarify these complex issues, we examined the association between lung function and infant-feeding practices.

METHODS

In the Tucson Children's Respiratory Study, feeding practices were assessed prospectively based on questionnaires completed at enrollment and well-child visits. Formula introduction was categorized as having occurred before 2 months (n = 143, "early formula introduction"), from 2 and before 4 months (n = 336), or at 4 months and older (n = 200, "longer breastfed"). Lung function was measured at age 11 and 16 years. A random-effects model was used to assess the relationship of infant-feeding practices to measures of lung function.

MEASUREMENTS AND MAIN RESULTS

FVC by age 16 was increased by 103 +/- 40.0 ml (P = 0.01), and the FEV1/FVC ratio was lower (-1.9 +/- 0.6%, P = 0.004) in the longer breastfed children compared with children with early formula introduction. This effect was modified after stratifying by maternal asthma. Compared with children with early formula introduction, longer breastfed children with asthmatic mothers had an FVC that was not increased (P = 0.7) and an FEV1/FVC ratio (-5.7 +/- 2.4%, P = 0.02) that was significantly decreased by age 16. Longer breastfed children with nonatopic, nonasthmatic mothers demonstrated an increased FVC (142 +/- 71.1 ml, P = 0.047) and no decrease in FEV1/FVC (P = 0.7) compared with children with early formula introduction.

CONCLUSIONS

Longer duration of breastfeeding favorably influences lung growth in children. However, in the presence of maternal asthma, longer breastfeeding is associated with decreased airflows.

Cytokines in human colostrum and neonatal jaundice

Breast-fed infants have higher bilirubin levels than formula-fed infants, possibly because of variations in the composition of the breast milk. The aim of this study was to investigate whether there is a relationship between cytokine levels in the colostrum of nursing mothers and neonatal jaundice (NJ). Breast milk samples were collected from breast-feeding mothers of healthy full-term neonates, 32 with NJ and 29 without jaundice. The concentrations of IL-1beta, IL-6, IL-8, IL-10, and tumor necrosis factor (TNF)-alpha were measured by chemiluminescence enzyme immunometric assays. Mothers of infants with NJ had a higher concentration of IL-1beta in colostrum, compared with those feeding neonates without NJ, and similar trends were seen for IL-6, IL-8, IL-10, and for TNF-alpha. The concentrations of IL-1beta significantly correlated with IL-6, IL-8, IL-10, and TNF-alpha concentrations, but not with serum bilirubin levels of infants with NJ. In conclusion, the concentrations of IL-1beta were increased in colostrum from breast-feeding mothers whose infants had NJ. The correlation between the concentrations of cytokines involved in the function of hepatic uptake and excretory systems and in the enterohepatic circulation of bilirubin provides additional data to the delineation of the cascade of pathophysiological events that can lead to NJ.

Interleukin-10 and -12 in human milk at 3 stages of lactation: a longitudinal study

This study was undertaken to analyze postpartum changes in concentrations of interleukin (IL)-10 and IL-12 through the 3 stages of lactation. A total of 87 human milk samples were collected from 29 healthy mothers during the colostrum (0-3 days), early milk (14-17 days), and mature milk (44-47 days) phases. Enzyme-linked immunosorbent assay tests were performed on the milk samples. IL-10 was detected in 7 and IL-12 in 4 of the colostrum samples. In the transitional milk samples, IL-10 was present in 4 and IL-12 in 2; however, both of these cytokines became undetectable in mature milk samples. The decrease in concentrations of IL-10 and IL-12 was statistically significant during the postpartum period (P=.001 and P=.024, respectively). IL-10 levels in the colostrum samples were higher than in the transitional samples (P=.018, with use of the post hoc test). No statistically significant differences between IL-12 levels were noted in the colostrum samples and the transitional samples (P=.068, with use of the post hoc test). A negative correlation was observed between concentrations of IL-10 in colostrum and the total number of pregnancies (R=-.401; P=.031). The findings of the present study suggest that mean concentrations of IL-10 and IL-12 are decreased in human milk as lactation continues through its 3 phases.

Cytokine profiling in human colostrum and milk by protein array

BACKGROUND

Human colostrum and milk contain components that influence development. Our aim was to use a protein array to determine the cytokine profile of human lacteal secretions and changes that occur during the early postpartum period.

METHODS

We collected 17 samples of colostrum during the first 2 days postpartum and a 2nd group of 5 sets of 2 to 3 sequential colostrum or milk samples (at 20- to 30-h intervals). We analyzed the samples with array membranes consisting of 42 or 79 antibodies directed against cytokines.

RESULTS

In most samples, we detected the previously described cytokines interleukin-8 (IL-8)/CXCL8, epidermal growth factor (EGF), growth-related oncoprotein (GRO)/CXCL1-3, angiogenin, transforming growth factor beta-2, and monocyte chemotactic protein 1 (MCP-1/CCL2). In addition, we found 32 cytokines that have not been described before in colostrum. Cytokine concentrations differed among mothers, and the spectrum of cytokines changed with time after delivery. A significant decrease occurred in IL-12 and macrophage inflammatory protein-1delta/CCL15 and a significant increase in MCP-1/CCL2. The production of angiogenin, vascular endothelial growth factor, GRO/CXCL1-3, EGF, and IL-8/CXCL8 remained high throughout. The concentrations of 2 selected cytokines measured with the array technique and ELISA showed moderate to strong correlation (r = 0.63 for EGF and r = 0.84 for IL-8/CXCL8).

CONCLUSION

Despite the lack of precise quantification, the protein array might be suitable for cytokine screening. It allows simultaneous detection of a broad spectrum of cytokines (including those not described before) in lacteal secretions.

Transfer of maternal cytokines to suckling piglets: in vivo and in vitro models with implications for immunomodulation of neonatal immunity

Maternal cytokines may play instructive roles in development of the neonatal immune system. However, cytokines in colostrum and milk and their transfer from mothers to neonates have not been well documented, except for TGF-beta. Swine provide a unique model to study lactogenic cytokines because the sow's impermeable placenta prohibits transplacental passage. We investigated IL-6 and TNF-alpha (pro-inflammatory), IFN-gamma and IL-12 (Th1), IL-10 and IL-4 (Th2) and TGF-beta1 (Th3) concentrations in sow serum and colostrum/milk and serum of their suckling and weaned piglets and in age-matched colostrum-deprived gnotobiotic piglets. All cytokines were detected in colostrum/milk and correlated with concentrations in sow serum except for mammary-derived TNF-alpha and TGF-beta1. Detection of IL-12 and TGF-beta1 in pre-suckling and colostrum-deprived gnotobiotic piglet serum suggests constitutive production: other cytokines were undetectable confirming absence of transplacental transfer. Peak median cytokine concentrations in suckling piglet serum occurred at post-partum days 1-2 (IL-4>IL-6>IFN-gamma>IL-10). The effects in vitro of physiologically relevant concentrations of the two predominant lactogenic cytokines (TGF-beta1 and IL-4) on porcine naive B cell responses to lipopolysaccharide (LPS) and rotavirus (RV) were investigated. High (10 ng/ml) TGF-beta1 suppressed immunoglobulin secreting cell responses to LPS and rotavirus; low concentrations (0.1 ng/ml) promoted isotype switching to IgA antibody. Interleukin-4 induced inverse dose-dependent (0.1 ng>10 ng/ml) isotype switching to IgA and enhanced IgM secreting cell responses to LPS and rotavirus. In summary, we documented the transfer and persistence of maternal cytokines from colostrum/milk to neonates and their potential role in Th-2 biased IgA responses and reduced immunologic responsiveness of neonates.

Expression of idiotypic antibodies-1 and -2 and breastfeeding in relation to antibody levels against Haemophilus influenzae type B in children

The aim of the study was to determine the concentrations of serum antibodies against Haemophilus influenzae type b in preschool children in relation to the distribution of idiotypic antibodies 1 and 2 (Id-1 and Id-2) and the exposure to breastfeeding in infancy. Sera were obtained from 74 control children recruited in an earlier case-control study before the introduction of general Hib vaccination. Duration of breastfeeding was monitored, and prevalence of noninvasive infections was registered. Concentrations of IgG1 and IgG2 anti-Hib, as well as of total Id-1 and Id-2, were determined in ELISA. The expression of Id-1 antibodies increased with age in contrast to the Id-2 antibodies that were found only in children up to 24 months of age. Expression of Id-1 antibodies was positively correlated with higher anti-Hib levels of both the IgG1 and IgG2 isotype. Children expressing Id-2 antibodies showed higher IgG2 anti-Hib concentrations than those who did not have Id-2 (P = 0.001). The concentrations of neither Id-1 nor Id-2 antibodies were related to the duration of breastfeeding. Duration of breastfeeding was related to increased anti-Hib IgG2 in healthy children above 18 months of age. These study shows that the expression of idiotype-1 and idiotype-2 antibodies was associated with higher IgG2 anti-Hib concentration and that breastfeeding could enhance the anti-Hib IgG2 production in children.

Effect of maternal smoking on breast milk interleukin-1alpha, beta-endorphin, and leptin concentrations and leptin concentrations

Tobacco smoke is immunotoxic, but the effect of smoking on the immunologic function of the mammary gland of mothers who smoke cigarettes ("smoker mothers") has not been studied. Our objective was to test, in smoker mothers, the colostral and transitional milk concentrations of interleukin-(IL)1alpha. The immunomodulators beta-endorphin and leptin were also tested. Pregnant women who self-identified as smokers (greater than or equal to 5 cigarettes per day through pregnancy) or nonsmokers were recruited for study participation. The study population included 42 smoker and 40 nonsmoker nursing mothers, with otherwise uncomplicated gestation, delivery, and puerperium, who were breast-feeding ad libitum their healthy neonates. Colostrum was obtained on the third postpartum day at 0900 hr and transitional milk on the 10th postpartum day at 0900 hr. IL-1alpha concentrations were significantly reduced in the colostrum of smoker mothers compared with nonsmoker mothers (p < 0.01). Colostral beta-endorphin and leptin concentrations were comparable. No significant differences were found between smoker and nonsmoker lactating mothers in transitional milk concentrations of IL-1alpha, beta-endorphin, and leptin. Moreover, beta-endorphin and leptin concentrations were significantly reduced in transitional milk samples compared with colostrum of both smoker and nonsmoker mothers (p < 0.05); also, IL-1alpha transitional milk concentrations were reduced compared with colostrum, but without any significance. This analysis shows that maternal smoking alters the colostral milk levels of the proinflammatory cytokine IL-1alpha. The altered postnatal provision of alternative source of the proinflammatory cytokine IL-1alpha adds understanding to how breast-feeding could be nonprotective against infections among the neonates nursed by smoker mothers.

Suppression of serum IgE response and systemic anaphylaxis in a food allergy model by orally administered high-dose TGF-β

Some epidemiological or association studies suggest that transforming growth factor-beta (TGF-beta) in breast milk may be a decisive factor in diminishing the risk of allergic diseases during infancy. The observations have prompted us to investigate whether TGF-beta, when taken orally, can affect allergic immune responses. Repeated high-dose ovalbumin peptide (OVA) feeding was previously reported to induce OVA-specific IgE production and an anaphylactic reaction after intravenous challenge of OVA in OVA-TCR transgenic mice, which might represent a model for food allergy. By using this model, we showed here that oral administration of high-dose TGF-beta simultaneously with OVA feeding significantly inhibited the OVA-specific IgE elevation and anaphylactic reaction in OVA-TCR transgenic DO11.10 mice. These effects were associated with suppression of OVA-specific IL-4 production and GATA-3 expression and with up-regulation of IFN-gamma production and T-bet expression by splenocytes. Intra-peritoneal injection of anti-TGF-beta-neutralizing antibody abolished the inhibitory effects of orally administered TGF-beta on the serum IgE response and anaphylactic reaction after OVA feeding in DO11.10 mice. Interestingly, oral administration of high-dose TGF-beta suppressed activation-induced T cell death induced by OVA feeding in DO11.10 mice. We thus conclude that TGF-beta, when taken orally at high dose, has the capacity to modulate a food allergy-related reaction, at least in part, through its systemic activity.

The effect of supplementation with fish oil during pregnancy on breast milk immunoglobulin A, soluble CD14, cytokine levels and fatty acid composition

BACKGROUND

Breast milk contains many immunomodulatory factors (soluble CD14 (sCD14), IgA and cytokines) with the potential to influence infant immune development.

OBJECTIVE

To determine if changes in breast milk omega-3 polyunsaturated fatty acid (n-3 PUFA) composition as a result of maternal dietary fish oil supplementation during pregnancy can modify levels of these immunological parameters in breast milk.

METHOD

In a randomized controlled trial, 83 atopic women received either 4 g fish oil capsules (containing 3.7 g n-3 PUFA) (n = 40) or 4 g olive oil capsules (n = 43) from 20 weeks gestation until delivery. Breast milk was collected 3 days post-partum and fatty acids were analysed by gas liquid chromatography and IgA, sCD14 and cytokines (IL-5, IL-6, IL-10, TNF-alpha and IFN-gamma) were quantitated by ELISA or time resolved fluorescence (TRF).

RESULTS

Omega-3 docosahexaenoic acid (DHA; 22:6n-3) and eicosapentaenoic acid (EPA; 20:5n-3) levels were significantly higher (P < 0.001) in breast milk from women supplemented with fish oil (n = 33, DHA mean 1.15%, SD 0.47% and EPA mean 0.16%, SD 0.07%) than in samples from the control group (n = 40, DHA mean 0.50%, SD 0.17% and EPA mean 0.05%, SD 0.02%). Breast milk arachidonic acid (AA; 20:4n-6) levels were significantly lower (P = 0.045) in the fish oil group (mean 0.55%, SD 0.12%) compared with the control group (mean 0.61%, SD 0.14%). Breast milk IgA was positively correlated with DHA (P = 0.046) and 22:5n-3 (P = 0.003), but inversely correlated with linoleic acid (LA; 18:2n-6) (P=0.034). Levels of sCD14 were also positively correlated with 22:5n-3 (P=0.009). Cytokines involved in IgA synthesis (IL-10 and IL-6) were also significantly correlated with both IgA and n-3 PUFA levels, although there were no differences in the levels of breast milk IgA, sCD14 or cytokines between study groups.

CONCLUSION

Supplementation with fish oil during pregnancy significantly alters early post-partum breast milk fatty acid composition. omega-3 PUFA levels were positively associated with IgA and sCD14 levels, suggesting a relationship between fatty acid status and mucosal immune function.

Different signalling pathways regulate VEGF and IL-8 expression in breast cancer: implications for therapy

Elevated expression of pro-angiogenic cytokines is associated with aggressive tumour growth and decreased survival of patients with breast cancer. In general, the breast cancer cell lines with high vascular endothelial growth factor (VEGF) expression also express high levels of interleukin-8 (IL-8). The consequence of inhibiting mitogen-activated protein kinase (MAPK) and phosphatidylinositol-3-kinase (PI3K), both implicated in regulation of these cytokines, was examined in four cell lines. Treatment with the mitogen-activated protein kinase/extracellular signal-related kinase (MEK) inhibitor U0126 reduced expression of VEGF and IL-8 in MDA-MB-231 cells, partially inhibited expression in MDA-MB-468 and Hs578T cells, with minimal effects in GI101A cells. Treatment with LY294002 reduced cytokine expression in GI101A and MDA-MB-468 cells, with partial reduction in Hs578T and less effect in MDA-MB-231 cells. Thus, IL-8 and VEGF were regulated by different signalling pathways in different cell lines; this suggests that inhibition of the dominantly active pathway can downregulate both angiogenic cytokines. Recognising which signalling pathway is active may identify targets for anti-angiogenic therapy of breast cancer.

Improved thymic function in exclusively breastfed infants is associated with higher interleukin 7 concentrations in their mothers' breast milk

BACKGROUND

In rural Gambians, the season of birth strongly predicts adult mortality. Those born during the harvest season have longer life spans than do those born during the hungry season, and the deaths associated with infectious diseases suggest permanent early-life influences on immunity. Thymic measurements showed significantly smaller thymuses in infants born during the hungry season than in those born during the harvest season. The differences were greatest at 8 wk of age, a time when all infants were exclusively breastfed, which suggests the involvement of breast milk factors.

OBJECTIVE

This study tested whether thymic size differences reflect thymic output and ascertained whether thymic output is associated with breast milk interleukin 7 (IL-7) concentrations.

DESIGN

We studied thymic size and output in a prospective cohort of 138 Gambian infants born in either the hungry or the harvest season by measuring signal-joint T cell receptor-rearrangement excision circles (sjTRECs) at birth and at 8 wk of age. IL-7 concentrations in breast milk were measured by using an enzyme-linked immunosorbent assay.

RESULTS

By age 8 wk, those born in the hungry season had significantly lower sjTREC counts than did those born in the harvest season (0.97 and 2.12 sjTRECs/100 T cells, respectively; P = 0.006). At 1 wk postpartum, the breast milk of mothers of infants born in the hungry season had significantly lower IL-7 than did that of mothers of infants born in the harvest season (79 and 100 pg/mL, respectively; P = 0.02). The findings were similar at 8 wk postpartum.

CONCLUSION

These data show a plausible pathway linking external seasonal insults to mothers with thymic development in their infants, which suggests possible implications for long-term programming of immunity.