Breast milk as the gold standard for protective nutrients

Factors that explain excretion of enteric pathogens by persons without diarrhea

Excretion of enteropathogens by subjects without diarrhea influences our appreciation of the role of these pathogens as etiologic agents. Characteristics of the pathogens and host and environmental factors help explain asymptomatic excretion of diarrheal pathogens by persons without diarrhea. After causing acute diarrhea followed by clinical recovery, some enteropathogens are excreted asymptomatically for many weeks. Thus, in a prevalence survey of persons without diarrhea, some may be excreting pathogens from diarrheal episodes experienced many weeks earlier. Volunteer challenges with Vibrio cholerae O1, enterotoxigenic Escherichia coli (ETEC), enteropathogenic E. coli, Campylobacter jejuni, and Giardia lamblia document heterogeneity among enteropathogen strains, with some inexplicably not eliciting diarrhea. The immune host may not manifest diarrhea following ingestion of a pathogen but may nevertheless asymptomatically excrete. Some human genotypes render them less susceptible to symptomatic or severe diarrheal infection with certain pathogens such as Vibrio cholerae O1 and norovirus. Pathogens in stools of individuals without diarrhea may reflect recent ingestion of inocula too small to cause disease in otherwise susceptible hosts or of animal pathogens (eg, bovine or porcine ETEC) that do not cause human illness.

Bovine colostrum improves intestinal function following formula-induced gut inflammation in preterm pigs

BACKGROUND & AIMS

Only few hours of formula feeding may induce proinflammatory responses and predispose to necrotizing enterocolitis (NEC) in preterm pigs. We hypothesized that bovine colostrum, rich in bioactive factors, would improve intestinal function in preterm pigs following an initial exposure to formula feeding after some days of total parenteral nutrition (TPN).

METHODS

After receiving TPN for 2 days, preterm pigs were fed formula (FORM, n = 14), bovine colostrum (COLOS, n = 6), or formula (6 h) followed by bovine colostrum (FCOLOS, n = 14). Intestinal lesions, function, and structure, abundance and location of bacteria, and inflammation markers were investigated.

RESULTS

NEC severity and interleukins (IL)-1β and -8 protein concentrations were lower, while villus height, galactose absorption, and brush-border enzyme activities were increased in the distal small intestine in COLOS and FCOLOS pigs, relative to FORM pigs. Intestinal gene expression of serum amyloid A, IL-1β, -6 and -8, and bacterial abundance, correlated positively with NEC severity of the distal small intestine.

CONCLUSIONS

Bovine colostrum restores intestinal function after initial formula-induced inflammation in preterm pigs. Further studies are required to test if bovine colostrum may also benefit preterm infants during the challenging transition from total parenteral nutrition to enteral nutrition, when human milk is unavailable.

Macrophage VLDL receptor promotes PAFAH secretion in mother's milk and suppresses systemic inflammation in nursing neonates

Mother’s milk is widely accepted as nutritious and protective to the newborn mammals by providing not only macronutrients but also immune-defensive factors. However, the mechanisms accounting for these benefits are not fully understood. Here we show that maternal very-low-density-lipoprotein receptor (VLDLR) deletion in mice causes the production of defective milk containing diminished level of platelet-activating factor acetylhydrolase (PAFAH). As a consequence, the nursing neonates suffer from alopecia, anemia and growth retardation owing to elevated levels of pro-inflammatory platelet-activating factors (PAFs). VLDLR deletion significantly impairs the expression of phospholipase A2 group 7 (Pla2g7) in macrophages, which decreases PAFAH secretion. Exogenous oral supplementation of neonates with PAFAH effectively rescues the toxicity. These findings not only reveal a novel role of VLDLR in suppressing inflammation by maintaining macrophage PAFAH secretion, but also identify the maternal VLDLR as a key genetic program that ensures milk quality and protects the newborns.

Bovine milk contains microRNA and messenger RNA that are stable under degradative conditions

We previously reported that microRNA (miRNA) is present in human breast milk. Recently, other groups have reported that bovine milk also contains miRNA; however, these reports are few. We therefore investigated bovine milk miRNA using microarray and quantitative PCR analyses to identify the differences between colostrum and mature milk. The RNA concentration in a colostrum whey fraction was higher than that in a mature milk whey fraction. In total, 102 miRNA were detected in bovine milk by microarray analysis (100 in colostrum and 53 in mature milk; 51 were common to both). Among these miRNA, we selected several immune- and development-related miRNA, including miR-15b, miR-27b, miR-34a, miR-106b, miR-130a, miR-155, and miR-223. These miRNA were detected in bovine milk by quantitative PCR, and each of these miRNA was significantly more highly expressed in colostrum than in mature milk. We also confirmed the presence of some mRNA in bovine milk. Nevertheless, synthesized miRNA spiked in the raw milk whey were degraded, and naturally existing miRNA and mRNA in raw milk were resistant to acidic conditions and RNase treatment. The RNA molecules in milk were stable. We also detected miRNA and mRNA in infant formulas purchased from Japanese markets. It is still unknown whether milk-derived RNA molecules play biological roles in infants; however, if milk-derived RNA do show functions in infants, our data will help guide future studies.

Purification of RNA from milk whey

MicroRNAs (miRNAs) are small regulatory RNA molecules that modulate specific target mRNAs and play very important roles in physiological processes. They were recently detected in body fluids such as blood, urine, saliva, and milk. These body fluid miRNAs have been studied thoroughly as potential diagnostic biomarkers. However, there have been few studies of milk miRNAs, and their roles are not clearly understood. Milk is the only nutritional source for newborn infants, and bovine milk is used widely as a dairy product. Thus, it is important to study milk miRNAs. In general, body fluid RNA concentrations are extremely low and of diverse existence types. In this chapter, we compare two silica membrane column-based RNA purification kits, and also compare RNA obtained directly from whey with that isolated from whey-derived exosomes.

Mining for liquid gold: midwifery language and practices associated with early breastfeeding support

Internationally, women give mixed reports regarding professional support during the early establishment of breastfeeding. Little is known about the components of midwifery language and the support practices, which assist or interfere with the early establishment of breastfeeding. In this study, critical discourse analysis has been used to describe the language and practices used by midwives when supporting breastfeeding women during the first week after birth. Participant observation at two geographically distant Australian health care settings facilitated the collection of 85 observed audio-recorded dyadic interactions between breastfeeding women and midwives during 2008-2009. Additionally, 23 interviews with women post discharge, 11 interviews with midwives and four focus groups (40 midwives) have also been analysed. Analysis revealed three discourses shaping the beliefs and practices of participating midwives. In the dominant discourse, labelled 'Mining for Liquid Gold', midwives held great reverence for breast milk as 'liquid gold' and prioritised breastfeeding as the mechanism for transfer of this superior nutrition. In the second discourse, labelled 'Not Rocket Science', midwives constructed breastfeeding as 'natural' or 'easy' and something which all women could do if sufficiently committed. The least well-represented discourse constructed breastfeeding as a relationship between mother and infant. In this minority discourse, women were considered to be knowledgeable about their needs and those of their infant. The language and practices of midwives in this approach facilitated communication and built confidence. These study findings suggest the need for models of midwifery care, which facilitate relationship building between mother and infant and mother and midwife.

Transcriptional and functional characterization of genetic elements involved in galacto-oligosaccharide utilization by Bifidobacterium breve UCC2003

Several prebiotics, such as inulin, fructo-oligosaccharides and galacto-oligosaccharides, are widely used commercially in foods and there is convincing evidence, in particular for galacto-oligosaccharides, that prebiotics can modulate the microbiota and promote bifidobacterial growth in the intestinal tract of infants and adults. In this study we describe the identification and functional characterization of the genetic loci responsible for the transport and metabolism of purified galacto-oligosaccharides (PGOS) by Bifidobacterium breve UCC2003. We further demonstrate that an extracellular endogalactanase specified by several B. breve strains, including B. breve UCC2003, is essential for partial degradation of PGOS components with a high degree of polymerization. These partially hydrolysed PGOS components are presumed to be transported into the bifidobacterial cell via various ABC transport systems and sugar permeases where they are further degraded to galactose and glucose monomers that feed into the bifid shunt. This work significantly advances our molecular understanding of bifidobacterial PGOS metabolism and its associated genetic machinery to utilize this prebiotic.

Breastfeeding in women with severe preeclampsia

BACKGROUND

In the United States, breastfeeding initiation is reported for 75% of all live births; however, little information is available for mothers affected by severe preeclampsia (SP) who because of magnesium sulfate treatment are separated from their infants in the immediate postpartum period. This study examined feeding practices and factors associated with breastfeeding initiation in 281 women with SP and their 200 late-preterm and 81 term infants.

SUBJECTS AND METHODS

SP was diagnosed according to established clinical and laboratory criteria. Infant feeding preference was ascertained on admission to labor and delivery. Variables known to influence breastfeeding initiation, including maternal age, smoking, obesity, and racial and educational characteristics, were assessed.

RESULTS

All mothers received magnesium sulfate for 24 hours following delivery. Of 281 infants, 54% were admitted to the neonatal intensive care unit (NICU). All mothers and infants survived. On admission, 149 women intended to breastfeed, 73 intended to feed formula, and 59 were undecided. Four of 73 women who did not wish to breastfeed and 27 of 59 originally undecided later initiated breastfeeding. At discharge, 144 (51%) of all these mothers had successfully initiated breastfeeding. Factors associated with breastfeeding initiation failure included African American race, younger age, lower education, multiparity, smoking, and obesity. Of 149 women who intended to breastfeed, 76% were successful, and logistic regression analysis showed that intention to breastfeed was the most significant predictor of breastfeeding initiation. During the first 24 hours postpartum, 78% of infants receiving well-baby care, and 4% of those admitted to the NICU visited with their mother once. Among women who intended to breastfeed, successful breastfeeding initiation involved 85% of infants receiving routine well-baby care and 69% of those admitted to the NICU.

CONCLUSIONS

In spite of the challenges created by SP, including early maternal separation, breastfeeding initiation is possible. The strongest predictor for breastfeeding success remains the intention to breastfeed, whereas race, lower level of education, and obesity are associated with breastfeeding initiation failure.

Chemotherapy, targeted agents, antiemetics and growth-factors in human milk: how should we counsel cancer patients about breastfeeding?

An increasing number of women are diagnosed with cancer during pregnancy and lactation. Women are usually advised to interrupt breastfeeding during systemic anticancer treatment for fear of serious adverse effects to the nursed infant. However, the issue is poorly addressed in the literature and very few studies have evaluated the safety of breastfeeding during or after cytotoxic drugs or target agents administration. In this review we will analyze the available evidence that addresses the issue of anticancer drugs, targeted agents, antiemetics and growth-factors excretion in human milk. This could serve as a unique resource that may aid physicians in the management of breastfeeding cancer patients interested in maintaining lactation during treatment.

Immune factors and fatty acid composition in human milk from river/lake, coastal and inland regions of China

Breast milk fatty acid composition may be affected by the maternal diet during gestation and lactation. The influence of dietary and breast milk fatty acids on breast milk immune factors is poorly defined. We determined the fatty acid composition and immune factor concentrations of breast milk from women residing in river/lake, coastal and inland regions of China, which differ in their consumption of lean fish and oily fish. Breast milk samples were collected on days 3–5 (colostrum), 14 and 28 post-partum (PP) and analysed for soluble CD14 (sCD14), transforming growth factor (TGF)-β1, TGF-β2, secretory IgA (sIgA) and fatty acids. The fatty acid composition of breast milk differed between the regions and with time PP. The concentrations of all four immune factors in breast milk decreased over time, with sCD14, sIgA and TGF-β1 being highest in the colostrum in the river and lake region. Breast milk DHA and arachidonic acid (AA) were positively associated, and γ-linolenic acid and EPA negatively associated, with the concentrations of each of the four immune factors. In conclusion, breast milk fatty acids and immune factors differ between the regions in China characterised by different patterns of fish consumption and change during the course of lactation. A higher breast milk DHA and AA concentration is associated with higher concentrations of immune factors in breast milk, suggesting a role for these fatty acids in promoting gastrointestinal and immune maturation of the infant.

Colostrum-derived B and T cells as an extra-lymphoid compartment of effector cell populations in humans

Colostrum contains cellular components that convey immunological protection to offspring. In the present study the main subsets of lymphocytes present in colostrum and in peripheral blood of healthy screened mothers were compared through the evaluation of >15 different flow cytometry markers. Colostrum and peripheral blood samples were collected within 3 days after full-term delivery. Flow cytometry assays and laboratory tests were performed soon after collection. Among B cells, percentages of CD19(+)CD5(+) cells, pertaining to natural immunity system, were significantly higher in colostrum than in peripheral blood (33 vs. 5%, p = 0.047). CD4(+) T cells, effector cells (CD45RA(+)/CD27(-)) and effector memory cells (CD45RA(-)/CD27(-)) were significantly higher in colostrum (p < 0.001) than in peripheral blood, as well as activated CD4(+) T cells (HLA(-)DR(+)) (36% vs. 6% p = 0.0022) and CD4(+) terminally differentiated effector T cells (CD57(+)) (p < 0.001). With regards to CD8(+) T cells, a comparable significant increase in effector (p < 0.02) and effector memory cells (p < 0.001) was also observed. Moreover, an increased surface expression of HLA-DR and CD57 (p < 0.001) on CD8(+) T cells in colostrum was detected. Colostrum contains a different distribution of lymphocyte subsets with respect to peripheral blood from mothers, confirming the observation that lymphocytes probably migrate in milk in a selective way. Colostrum T and B lymphocytes appear to be enriched with subsets possessing effector functions or belonging to the innate immune system, what could transfer a prompt line of defence to offspring.

Anti-inflammatory effects of Lacto-Wolfberry in a mouse model of experimental colitis

AIM: To investigate the anti-inflammatory properties of Lacto-Wolfberry (LWB), both in vitro and using a mouse model of experimental colitis.

METHODS: The effects of LWB on lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) and interleukin (IL)-6 secretion were assessed in a murine macrophage cell line. in vitro assessment also included characterizing the effects of LWB on the activation of NF-E2 related 2 pathway and inhibition of tumor necrosis factor-α (TNF-α)-induced nuclear factor-κB (NF-κB) activation, utilizing reporter cell lines. Following the in vitro assessment, the anti-inflammatory efficacy of an oral intervention with LWB was tested in vivo using a preclinical model of intestinal inflammation. Multiple outcomes including body weight, intestinal histology, colonic cytokine levels and anti-oxidative measures were investigated.

RESULTS: LWB reduced the LPS-mediated induction of ROS production [+LPS vs 1% LWB + LPS, 1590 ± 188.5 relative luminescence units (RLU) vs 389 ± 5.9 RLU, P < 0.001]. LWB was more effective than wolfberry alone in reducing LPS-induced IL-6 secretion in vitro (wolfberry vs 0.5% LWB, 15% ± 7.8% vs 64% ± 5%, P < 0.001). In addition, LWB increased reporter gene expression via the anti-oxidant response element activation (wolfberry vs LWB, 73% ± 6.9% vs 148% ± 28.3%, P < 0.001) and inhibited the TNF-α-induced activation of the NF-κB pathway (milk vs LWB, 10% ± 6.7% vs 35% ± 3.3%, P < 0.05). Furthermore, oral supplementation with LWB resulted in a reduction of macroscopic (-LWB vs +LWB, 5.39 ± 0.61 vs 3.66 ± 0.59, P = 0.0445) and histological scores (-LWB vs +LWB, 5.44 ± 0.32 vs 3.66 ± 0.59, P = 0.0087) in colitic mice. These effects were associated with a significant decrease in levels of inflammatory cytokines such as IL-1β (-LWB vs +LWB, 570 ± 245 μg/L vs 89 ± 38 μg/L, P = 0.0106), keratinocyte-derived chemokine/growth regulated protein-α (-LWB vs +LWB, 184 ± 49 μg/L vs 75 ± 20 μg/L, P = 0.0244), IL-6 (-LWB vs +LWB, 318 ± 99 μg/L vs 117 ± 18 μg/L, P = 0.0315) and other pro-inflammatory proteins such as cyclooxygenase-2 (-LWB vs +LWB, 0.95 ± 0.12 AU vs 0.36 ± 0.11 AU, P = 0.0036) and phosphorylated signal transducer and activator of transcription-3 (-LWB vs +LWB, 0.51 ± 0.15 AU vs 0.1 ± 0.04 AU, P = 0.057). Moreover, antioxidant biomarkers, including expression of gene encoding for the glutathione peroxidase, in the colon and the plasma anti-oxidant capacity were significantly increased by supplementation with LWB (-LWB vs +LWB, 1.2 ± 0.21 mmol/L vs 2.1 ± 0.19 mmol/L, P = 0.0095).

CONCLUSION: These results demonstrate the anti-inflammatory properties of LWB and suggest that the underlying mechanism is at least in part due to NF-κB inhibition and improved anti-oxidative capacity.

Nutritional factors influencing intestinal health of the neonate

Dietary nutrients are essential for gastrointestinal (GI) growth and function, and nutritional support of GI growth and development is a significant component of infant care. For healthy full-term neonates, nutritional provisions of the mother's milk and/or formula will support normal maturation of structure and function of the GI tract in most infants. The composition of breast milk affects GI barrier function and development of a competent mucosal immune system. The functional nutrients and other bioactive components of milk support a microenvironment for gut protection and maturation. However, premature infants struggle with feeding tolerance impairing normal GI function, leading to intestinal dysfunction and even death. The high prevalence worldwide of enteric diseases and dysfunction in neonates has led to much interest in understanding the role of nutrients and food components in the establishment and maintenance of a functioning GI tract. Neonates who do not receive enteral feeding as either mother's milk or formula are supported by total parental nutrition (TPN). The lack of enteral nutrition can compound intestinal dysfunction, leading to high morbidity and mortality in intestinally compromised infants. Reciprocally, enteral stimulation of an immature GI tract can also compound intestinal dysfunction. Therefore, further understanding of nutrient interactions with the mucosa is necessary to define nutritional requirements of the developing GI tract to minimize intestinal complications and infant morbidity. Piglet models of intestinal development and function are similar to humans, and this review summarizes recent findings regarding nutrient requirements for growth and maintenance of intestinal health. In particular, this article reviews the role of specific amino acids (arginine, glutamine, glutamate, and threonine), fatty acids (long chain polyunsaturated, medium chain, and short chain), various prebiotic carbohydrates (short-chain fructo-oligosaccharide, fructo--oligosaccharide, lacto-N-neotetraose, human milk oligosaccharide, polydextrose, and galacto-oligosaccharide), and probiotics that have been examined in the suckling piglet model of intestinal health.

Development of serum IgA and IgM levels in breast-fed and formula-fed infants during the first week of life

BACKGROUND

IgA and IgM antibodies play important roles to protect infants in early life

AIM

To study the effects of breast milk feeding versus formula feeding in early infancy on the development of serum IgA and IgM.

METHODS

A group of 220 healthy infants born after uncomplicated pregnancies and deliveries were enrolled. The infants were divided into three groups according to feeding type: breast-fed (BF), formula-fed (FF), and mixed-fed (MF). Capillary blood was collected for serum IgA and IgM detection at the first week of life.

RESULTS

The average concentrations of serum IgA and IgM in all infants were 1.171±1.079 and 256.2±165.8 μg/ml, respectively. There were significantly higher concentrations of serum IgA in the FF group than MF group at 3, 4 and 6 days of age and BF group at 5 and 6 days old. Paired serum IgA concentrations revealed that IgA significantly decreased in the BF group, but not in the FF and MF groups. Meanwhile, paired serum IgM concentrations revealed that IgM increased significantly during early infancy in all groups. However, the IgM levels had no difference among the 3 groups within 7 days of age.

CONCLUSIONS

Our study demonstrated the development of serum IgA and IgM in early life. Formula feeding induced higher serum IgA concentrations than breast-feeding within 7 days of age. However, serum IgM concentration was significantly increased in early life in all groups but had no differences between the different feeding types. Breast-feeding may protect antigen loading in early life.

The human milk microbiome changes over lactation and is shaped by maternal weight and mode of delivery

BACKGROUND

Breast milk is recognized as the most important postpartum element in metabolic and immunologic programming of health of neonates. The factors influencing the milk microbiome and the potential impact of microbes on infant health have not yet been uncovered.

OBJECTIVE

Our objective was to identify pre- and postnatal factors that can potentially influence the bacterial communities inhabiting human milk.

DESIGN

We characterized the milk microbial community at 3 different time points by pyrosequencing and quantitative polymerase chain reaction in mothers (n = 18) who varied in BMI, weight gain, and mode of delivery.

RESULTS

We found that the human milk microbiome changes over lactation. Weisella, Leuconostoc, Staphylococcus, Streptococcus, and Lactococcus were predominant in colostrum samples, whereas in 1- and 6-mo milk samples the typical inhabitants of the oral cavity (eg, Veillonella, Leptotrichia, and Prevotella) increased significantly. Milk from obese mothers tended to contain a different and less diverse bacterial community compared with milk from normal-weight mothers. Milk samples from elective but not from nonelective mothers who underwent cesarean delivery contained a different bacterial community than did milk samples from individuals giving birth by vaginal delivery, suggesting that it is not the operation per se but rather the absence of physiological stress or hormonal signals that could influence the microbial transmission process to milk.

CONCLUSIONS

Our results indicate that milk bacteria are not contaminants and suggest that the milk microbiome is influenced by several factors that significantly skew its composition. Because bacteria present in breast milk are among the very first microbes entering the human body, our data emphasize the necessity to understand the biological role that the milk microbiome could potentially play for human health.

Liquid gold from the milk bar: constructions of breastmilk and breastfeeding women in the language and practices of midwives

Midwives are the main health professional group providing support and assistance to women during the early establishment of breastfeeding. In published accounts of early breastfeeding experiences women report high levels of dissatisfaction with health professional support. To gain an understanding of this dissatisfaction, we examined the way in which midwives represent breastmilk and construct breastfeeding women in their interactions. Seventy seven women and seventy six midwives at two maternity units in NSW, Australia, participated in this study. Eighty five interactions between a midwife and a breastfeeding woman were observed and audio recorded during the first week after birth. In addition, data were collected through observation of nine parenting education sessions, interviews with 23 women following discharge, and 11 managers and lactation consultants (collected between October 2008 and September 2009). Discourse analysis was used to analyse the transcribed interactions, and interview data. The analysis revealed that midwives prioritised both colostrum and mature breastmilk as a 'precious resource', essential for the health and wellbeing of the infant and mother. References to breastmilk as 'liquid gold' were both verbal and implied. Within this discourse, the production and acquisition of 'liquid gold' appeared to be privileged over the process of breastfeeding and women were, at times, positioned as incompetent operators of their bodily 'equipment', lacking knowledge and skill in breastfeeding. In this context breastfeeding became constructed as a manufacturing process for a demanding consumer. The approach taken by midwives revealed an intensive focus on nutrition to the exclusion of relational communication and support. The findings indicate the need to challenge the current 'disciplinary' and 'technological' practices used by midwives when providing breastfeeding support and the need for a cultural change in postnatal care.

Effects of freezing on the bactericidal activity of human milk

OBJECTIVES

Storage of human milk by freezing has been recommended for long-term storage. The present study analyzed the bactericidal activity of human milk on Escherichia coli and Pseudomonas aeruginosa and determined the changes in bactericidal activity following freezing at -20°C and -80°C for 1 month and 3 months.

METHODS

Forty-eight milk samples were collected from 48 lactating mothers. Each sample was divided into 10 aliquots. Two of the samples were processed immediately and the others were stored at both -20°C and -80°C until analysis after 1 month and 3 months of freezing.

RESULTS

All of the fresh milk samples showed bactericidal activity against E coli and P aeruginosa. Freezing at -20°C for 1 month did not cause statistically significant alteration in bactericidal activity (P > 0.017), whereas storage for 3 months lowered the degree of bactericidal activity significantly (P < 0.017) against E coli. Bactericidal activity was protected when the samples were stored at -80°C. There was no statistically significant difference in the bactericidal activity of human milk against E coli between freezing at -20°C and -80°C for 1 month (P > 0.017); however, when milk was stored for 3 months, -80°C was significantly more protective (P < 0.017). Freezing at -20°C and -80°C for 1 month and 3 months did not cause any significant change in bactericidal activity against P aeruginosa (P > 0.05).

CONCLUSIONS

Storage by freezing at -80°C is more appropriate to keep bactericidal capacity of stored human milk >1 month if affordable and available, especially in intensive care settings.

Salmon consumption during pregnancy alters fatty acid composition and secretory IgA concentration in human breast milk

Fish oil supplementation during pregnancy alters breast milk composition, but there is little information about the impact of oily fish consumption. We determined whether increased salmon consumption during pregnancy alters breast milk fatty acid composition and immune factors. Women (n = 123) who rarely ate oily fish were randomly assigned to consume their habitual diet or to consume 2 portions of farmed salmon per week from 20 wk of pregnancy until delivery. The salmon provided 3.45 g long-chain (LC) (n-3) PUFA/wk. Breast milk fatty acid composition and immune factors [soluble CD14, transforming growth factor-β (TGFβ)1, TGFβ2, and secretory IgA] were analyzed at 1, 5, 14, and 28 d postpartum (PP). Breast milk from the salmon group had higher proportions of EPA (80%), docosapentaenoic acid (30%), and DHA (90%) on d 5 PP compared with controls (P < 0.01). The LC (n-6) PUFA:LC (n-3) PUFA ratio was lower for the salmon group on all days of PP sampling (P ≤ 0.004), although individual (n-6) PUFA proportions, including arachidonic acid, did not differ. All breast milk immune factors decreased between d 1 and 28 PP (P < 0.001). Breast milk secretory IgA (sIgA) was lower in the salmon group (d 1-28 PP; P = 0.006). Salmon consumption during pregnancy, at the current recommended intakes, increases the LC (n-3) PUFA concentration of breast milk in early lactation, thus improving the supply of these important fatty acids to the breast-fed neonate. The consequence of the lower breast milk concentration of sIgA in the salmon group is not clear.

Maternal weight and excessive weight gain during pregnancy modify the immunomodulatory potential of breast milk

INTRODUCTION

Breast milk is an optimal source of nutrition for infants. It contains bioactive components including bacteria that support the microbial colonization and immune system development of the infant. The determinants of human milk composition remain poorly understood, although maternal nutritional and immunological status as well as lifestyle and dietary habits seem to have an impact.

METHODS

The subjects selected were women from a prospective follow-up study categorized by BMI. Milk samples were taken after delivery and at 1 and 6 mo later for analysis of composition in regard to transforming growth factor (TGF)-β2, soluble CD14 (sCD14), cytokines, and microbiota.

RESULTS

TGF-β2 and sCD14 levels in the breast milk of overweight mothers tended to be lower than the levels in that of normal-weight mothers. Also, higher levels of Staphylococcus group bacteria and lower levels of Bifidobacterium group bacteria were detected in overweight mothers as compared with normal-weight ones. The prevalence of Akkermansia muciniphila-type bacteria was also higher in overweight mothers, and the numbers of these bacteria were related to the interleukin (IL)-6 concentration in the colostrum, which was in turn related to lower counts of Bifidobacterium group bacteria in the breast milk of overweight women.

DISCUSSION

Complex interactions of cytokines and microbiota in breast milk guide the microbiological, immunological, and metabolic programming of infant health. Our data may indicate the presence of an additional mechanism that may explain the heightened risk of obesity for infants of overweight and excessive weight gain mothers.

Microbial ecology and host-microbiota interactions during early life stages

The role of human microbiota has been redefined during recent years and its physiological role is now much more important than earlier understood. Intestinal microbial colonization is essential for the maturation of immune system and for the developmental regulation of the intestinal physiology. Alterations in this process of colonization have been shown to predispose and increase the risk to disease later in life. The first contact of neonates with microbes is provided by the maternal microbiota. Moreover, mode of delivery, type of infant feeding and other perinatal factors can influence the establishment of the infant microbiota. Taken into consideration all the available information it could be concluded that the exposure to the adequate microbes early in gestation and neonatal period seems to have a relevant role in health. Maternal microbial environment affects maternal and fetal immune physiology and, of relevance, this interaction with microbes at the fetal-maternal interface could be modulated by specific microbes administered to the pregnant mother. Indeed, probiotic interventions aiming to reduce the risk of immune-mediated diseases may appear effective during early life.

Defining microbiota for developing new probiotics

The human body harbors complex communities of microbes that play a prominent role in human health. Detailed characterization of the microbiota in the target population forms the basis of probiotic use. Probiotics are defined as live bacterial preparations with clinically documented health effects in humans, and independent of their genus and species, probiotic strains are unique and their beneficial properties on human health have to be assessed in a case-by-case manner. Understanding the mechanisms by which probiotics influence microbiota would facilitate the use of probiotics for both dietary management and reduction in risk of specific diseases. The development of high throughput sequencing methods has allowed metagenomic approaches to study the human microbiome. These efforts are starting to generate an inventory of bacterial taxons and functional features bound to particular health or disease status that allow inferring aspects of the microbiome's function. In the future, this information will allow the rational design of dietary interventions aimed to improve consumer's health via modulation of the microbiota.

Lactation and neonatal nutrition: defining and refining the critical questions

This paper resulted from a conference entitled "Lactation and Milk: Defining and refining the critical questions" held at the University of Colorado School of Medicine from January 18-20, 2012. The mission of the conference was to identify unresolved questions and set future goals for research into human milk composition, mammary development and lactation. We first outline the unanswered questions regarding the composition of human milk (Section I) and the mechanisms by which milk components affect neonatal development, growth and health and recommend models for future research. Emerging questions about how milk components affect cognitive development and behavioral phenotype of the offspring are presented in Section II. In Section III we outline the important unanswered questions about regulation of mammary gland development, the heritability of defects, the effects of maternal nutrition, disease, metabolic status, and therapeutic drugs upon the subsequent lactation. Questions surrounding breastfeeding practice are also highlighted. In Section IV we describe the specific nutritional challenges faced by three different populations, namely preterm infants, infants born to obese mothers who may or may not have gestational diabetes, and infants born to undernourished mothers. The recognition that multidisciplinary training is critical to advancing the field led us to formulate specific training recommendations in Section V. Our recommendations for research emphasis are summarized in Section VI. In sum, we present a roadmap for multidisciplinary research into all aspects of human lactation, milk and its role in infant nutrition for the next decade and beyond.

Sialic acid utilization

Early postnatal development encounters milk as a key environmental variable and yet the sole nutrient source. One evolutionary conserved constituent of milk is sialic acid, which is generally displayed on glycoconjugates and free glycans. During early postnatal development, high sialic acid need was proposed to be unmet by the endogenous sialic acid synthetic capacity. Hence, milk sialic acid was proposed to serve as a conditional nutrient for the newborn. In the elderly, at the other end of ontogeny, decreased sialylation in the brain, saliva, and immune system is observed. Analogous to the neonatal situation, the endogenous synthetic capacity may be unable to keep up with the need in this age group. The data discussed here propose a functional dietary role of sialic acid as a building block for sialylation and beyond.

A molecular basis for bifidobacterial enrichment in the infant gastrointestinal tract

Bifidobacteria are commonly used as probiotics in dairy foods. Select bifidobacterial species are also early colonizers of the breast-fed infant colon; however, the mechanism for this enrichment is unclear. We previously showed that Bifidobacterium longum subsp. infantis is a prototypical bifidobacterial species that can readily utilize human milk oligosaccharides as the sole carbon source. MS-based glycoprofiling has revealed that numerous B. infantis strains preferentially consume small mass oligosaccharides, abundant in human milks. Genome sequencing revealed that B. infantis possesses a bias toward genes required to use mammalian-derived carbohydrates. Many of these genomic features encode enzymes that are active on milk oligosaccharides including a novel 40-kb region dedicated to oligosaccharide utilization. Biochemical and molecular characterization of the encoded glycosidases and transport proteins has further resolved the mechanism by which B. infantis selectively imports and catabolizes milk oligosaccharides. Expression studies indicate that many of these key functions are only induced during growth on milk oligosaccharides and not expressed during growth on other prebiotics. Analysis of numerous B. infantis isolates has confirmed that these genomic features are common among the B. infantis subspecies and likely constitute a competitive colonization strategy used by these unique bifidobacteria. By detailed characterization of the molecular mechanisms responsible, these studies provide a conceptual framework for bifidobacterial persistence and host interaction in the infant gastrointestinal tract mediated in part through consumption of human milk oligosaccharides.

Comparison of maternal milk (breastmilk) expression methods in an African nursery

OBJECTIVE

This study compares maternal milk volumes (MMVs) of Ugandan mothers whose infants were in a special care nursery and who used one of three maternal milk expression techniques: double electric breast pump, single non-electric manual breast pump, and hand breastmilk expression.

SUBJECTS AND METHODS

A convenience sample of 161 Ugandan mothers of infants who were either too immature or ill to independently feed from the breast yet healthy enough to survive in an environment without ventilator support (birth weights, 0.84-3.8 kg) were assigned to one of three maternal milk expressions: Group 1, double electric breast pump (n=55); Group 2, single non-electric manual breast pump (n=59); and Group 3, hand breastmilk expression (n=47). Data were collected over a 7-day period (from day 1 postpartum to day 7 postpartum), and mean MMVs were measured and compared among the groups.

RESULTS

The mean daily MMVs were as follows: Group 1, mean=647 mL (SD=310); Group 2, mean=520 mL (SD=298); and Group 3, mean=434 mL (SD=291). Results from one-way analysis of variance revealed significant differences in the mean MMV based on the method of maternal milk expression (p=0.0019). Further analysis using Tukey's HSD Test revealed significant differences in the MMV between Groups 1 and 3 (p < 0.01), but not between Groups 1 and 2 or between Groups 2 and 3.

CONCLUSIONS

Electric breast pumps provided the highest mean MMV; however, many mothers obtained adequate feeding volumes for their infants' daily nutritional needs with the single non-electric manual breast pump and hand breastmilk expression.

The human obesity epidemic, the mismatch paradigm, and our modern "captive" environment

In the distant past obesity in humans was rare and likely caused by metabolic dysregulation due to genetic or disease-related pathology. External factors precluded the ability of most people to overeat or under exert. Socio-cultural obesity came about due to the rareness of obesity and its difficulty to achieve. What is rare becomes valuable and what is difficult to achieve becomes a badge of prestige. The modern human obesity epidemic would appear to represent a third class of obesity: environmental obesity. Much like the captive environments which humans construct for the captive/companion animals in our care, the modern human environment has greatly decreased the challenges of life that would restrict food intake and enforce exertion. And like us, our captive/companion animal populations are also experiencing obesity epidemics. A further concern is that maternal obesity alters maternal signaling to offspring, in utero through the placenta and after birth through breast milk, in ways that perpetuate an enhanced vulnerability to obesity. Molecules such as leptin, produced by adipose tissue and placenta, have significant developmental effects on brain areas associated with feeding behavior. Leptin and other cytokines and growth factors are found in breast milk. These molecules have positive effects on gut maturation; their effects on metabolism and brain development are unclear. Placenta and brain also are hotspots for epigenetic regulation, and epigenetic changes may play significant roles in the later vulnerability to obesity and to the development of a diverse array of diseases, including heart disease, hypertension, and noninsulin-dependent diabetes.

The early settlers: intestinal microbiology in early life

The human intestinal microbiota forms an integral part of normal human physiology, and disturbances of the normal gut microbiology have been implicated in many health and disease issues. Because newborns are essentially sterile, their microbiota must establish and develop from the very first days of life. The first colonizers play an important role in the development of the ecosystem and may impact the long-term composition and activity of the microbiota. These first settlers obviously develop and proliferate dependent on host characteristics and diet, but other factors can also significantly contribute to this vital biological process. Considering the importance of the microbiota for the human immune, metabolic, and neurological systems, it is important to understand the dynamics and driving determinants of this development. This review gives a global overview of our current understanding of the different factors impacting the intestinal microbiology in early life.

Effect of nutritional supplementation of breastfeeding HIV positive mothers on maternal and child health: findings from a randomized controlled clinical trial

BACKGROUND

It has been well established that breastfeeding is beneficial for child health, however there has been debate regarding the effect of lactation on maternal health in the presence of HIV infection and the need for nutritional supplementation in HIV positive lactating mothers.

AIMS

To assess the effect of nutritional supplementation to HIV infected lactating mothers on nutritional and health status of mothers and their infants.

METHODS

A randomized controlled clinical trial to study the impact of nutritional supplementation on breastfeeding mothers. Measurements included anthropometry; body composition indicators; CD4 count, haemoglobin and albumin; as well as incidence rates of opportunistic infections; depression and quality of life scores. Infant measurements included anthropometry, development and rates of infections.

RESULTS

The supplement made no significant impact on any maternal or infant outcomes. However in the small group of mothers with low BMI, the intake of supplement was significantly associated with preventing loss of lean body mass (1.32 kg vs. 3.17 kg; p = 0.026). There was no significant impact of supplementation on the infants.

CONCLUSIONS

A 50 g daily nutritional supplement to breastfeeding mothers had no or limited effect on mother and child health outcomes.

CLINICAL TRIAL REGISTRATION

ISRCTN68128332 (http://www.controlled-trials.com/ISRCTN68128332).

Impact of cotrimoxazole prophylaxis on the health of breast-fed, HIV-exposed, HIV-negative infants in a resource-limited setting

WHO guidelines recommend cotrimoxazole prophylaxis (CTXP) in all HIV-exposed negative infants who are still breastfeeding. This is based on the evidence of efficacy in HIV-infected infants, but there is no evidence of benefit in HIV-negative, breast-fed infants. We assessed the impact of CTXP on diarrhoeal and respiratory morbidity in breast-fed, HIV-exposed negative infants in a community programme. CTXP for more than 60 days showed no consistent evidence of benefit for incidence of lower respiratory tract infection [incidence rate ratio (IRR) 0.71, 95% confidence interval (CI) 0.39-1.26; P = 0.241] but an increased incidence of diarrhoea (IRR = 1.38, 95% CI 0.98-1.94; P = 0.065). The guidelines should be reconsidered by conducting a randomized control trial.

Ovalbumin-specific immunoglobulins A and G levels at age 2 years are associated with the occurrence of atopic disorders

BACKGROUND

Humoral responses to food antigens may reflect the propensity of a child's immune system to develop tolerance to innocuous antigens. Early nutrition as well as probiotics may influence these immunological responses.

OBJECTIVE

To study the association of humoral responses to early food antigens with the administration of prebiotics and probiotics, with the occurrence of allergy, and with the length of exclusive breastfeeding.

METHODS

In a randomized double-blind allergy prevention trial in high-risk children, 1018 mothers took probiotics or placebo from the 36th week of gestation, and their newborn infants received probiotics and prebiotics or placebo during 6 months. At 2 and 5 years, we evaluated the cumulative incidence of allergic diseases (food allergy, eczema, asthma, rhinitis) and sensitization (skin prick test ≥3 mm or serum antigen-specific IgE>0.7 kU/L). In 688 infants at age 2, we measured in sera-specific IgA, IgG, IgG1, and IgG4 antibody levels to cow's milk (CM), α-casein (CAS), β-lactoglobulin (BLG), and ovalbumin (OVA) with ELISA, and specific IgE levels to CM and hen's egg with UniCap.

RESULTS

Probiotic treatment (n=342) compared with placebo (n=346) showed no effect on serum food-specific IgA, IgG, IgG1, or IgG4 concentrations at age 2. Atopic children had higher OVA-IgA (P<0.001), OVA-IgG (P=0.001), OVA-IgG1 (P<0.001), and egg-IgE but lower OVA-IgG4/egg-IgE ratio (P<0.001) than non-atopic children. Longer duration of exclusive breastfeeding (≥4 vs. <4 months) was associated with reduced CM- and CAS-specific serum IgA (P<0.001) and IgG levels (P<0.001; P=0.003).

CONCLUSION AND CLINICAL RELEVANCE

Allergy was associated with more intense IgA and IgG responses to OVA. Breastfeeding depressed humoral responses, whereas prebiotics and probiotics supplementation showed no immunomodulatory effect. The effect of probiotics on allergies is not mediated through food-specific antibody responses. Furthermore, OVA-specific IgA and IgG antibodies may help in assessing the risk for atopy.

Immunology of gut mucosal vaccines

Understanding the mechanisms underlying the induction of immunity in the gastrointestinal mucosa following oral immunization and the cross-talk between mucosal and systemic immunity should expedite the development of vaccines to diminish the global burden caused by enteric pathogens. Identifying an immunological correlate of protection in the course of field trials of efficacy, animal models (when available), or human challenge studies is also invaluable. In industrialized country populations, live attenuated vaccines (e.g. polio, typhoid, and rotavirus) mimic natural infection and generate robust protective immune responses. In contrast, a major challenge is to understand and overcome the barriers responsible for the diminished immunogenicity and efficacy of the same enteric vaccines in underprivileged populations in developing countries. Success in developing vaccines against some enteric pathogens has heretofore been elusive (e.g. Shigella). Different types of oral vaccines can selectively or inclusively elicit mucosal secretory immunoglobulin A and serum immunoglobulin G antibodies and a variety of cell-mediated immune responses. Areas of research that require acceleration include interaction between the gut innate immune system and the stimulation of adaptive immunity, development of safe yet effective mucosal adjuvants, better understanding of homing to the mucosa of immunologically relevant cells, and elicitation of mucosal immunologic memory. This review dissects the immune responses elicited in humans by enteric vaccines.

Prophylactic application of bovine colostrum ameliorates murine colitis via induction of immunoregulatory cells

Epidemiologic studies suggest a relationship between early weaning and the incidence of inflammatory bowel disease. Herein, we addressed the question whether bovine colostrum, the first milk produced by mammals, is able to prevent dextran sulfate sodium (DSS)-induced colitis in mice. Prior to induction of colitis with 5% DSS, Naval Medical Research Institute mice were fed bovine colostrum [BV-20 or 200 mg/kg body weight (BW)], BSA (20 mg/kg BW), or water (100 μL) daily by oral gavage for 2 wk. The clinical severity of colitis was determined by scoring changes in BW and colon length reduction. Following 2 wk of observation, the colons were removed for histologic and immunohistochemical evaluation of inflammation. Flow cytometric phenotyping of leukocyte subsets was performed from peripheral blood, mesenteric lymph nodes, and spleens. Administration of bovine colostrum improved the clinical and histologic severity of colorectal inflammation. Compared with BSA-fed and water-fed controls, BV-20 pretreated mice had significantly less severe weight loss and decreased colon shortening. Beneficial effects were accompanied by redistribution of immunoregulatory, peripheral and splenic γδ TCR(+) cells, and CD11b(+)Gr1(+) cells. Higher colostrum doses did not affect disease activity. In summary, prophylactic administration of colostrum improved clinical symptoms of colorectal inflammation in a well-established mouse model of DSS-induced colitis. Further investigations will target the underlying immunomodulatory mechanisms to our approach.

The host defense proteome of human and bovine milk

Milk is the single source of nutrients for the newborn mammal. The composition of milk of different mammals has been adapted during evolution of the species to fulfill the needs of the offspring. Milk not only provides nutrients, but it also serves as a medium for transfer of host defense components to the offspring. The host defense proteins in the milk of different mammalian species are expected to reveal signatures of evolution. The aim of this study is therefore to study the difference in the host defense proteome of human and bovine milk. We analyzed human and bovine milk using a shot-gun proteomics approach focusing on host defense-related proteins. In total, 268 proteins in human milk and 269 proteins in bovine milk were identified. Of these, 44 from human milk and 51 from bovine milk are related to the host defense system. Of these proteins, 33 were found in both species but with significantly different quantities. High concentrations of proteins involved in the mucosal immune system, immunoglobulin A, CD14, lactoferrin, and lysozyme, were present in human milk. The human newborn is known to be deficient for at least two of these proteins (immunoglobulin A and CD14). On the other hand, antimicrobial proteins (5 cathelicidins and lactoperoxidase) were abundant in bovine milk. The high concentration of lactoperoxidase is probably linked to the high amount of thiocyanate in the plant-based diet of cows. This first detailed analysis of host defense proteins in human and bovine milk is an important step in understanding the function of milk in the development of the immune system of these two mammals.

Reduction of Escherichia coli O157:H7 excretion in sheep by oral lactoferrin administration

Ruminants are an important reservoir of Escherichia coli O157:H7, therefore reducing E. coli O157:H7 excretion by these animals could play a key role in reducing human infections. The present study investigates the potential of bovine lactoferrin, a natural antimicrobial-immunomodulatory protein of milk, to prevent colonization and excretion of E. coli O157:H7 in sheep. The effect of two different doses of lactoferrin (1.5 g or 0.15 g per 12h) was evaluated on colonization of sheep intestine and faecal excretion of the NCTC12900 strain. Hereto, lactoferrin was orally administered to sheep during 30 consecutive days and sheep were experimentally infected with E. coli O157:H7 on the second day of the lactoferrin administration. Interestingly, both lactoferrin dosages significantly reduced the number of E. coli O157:H7 in faeces as well as the duration of faecal excretion. The high dose group showed a significantly higher antibody response against EspA and EspB, two structural proteins of the bacterial type III secretion system (TTSS), than the colonization control group. The results suggest that oral lactoferrin administration could be used to prevent persistent colonization of sheep with E. coli O157:H7.

Pediatric surgery and the human microbiome

Bold advances in the past decade have made it possible to carefully study the contributions of microbes to normal human development and to disease pathogenesis. The intestinal microbiota has been implicated in adult diseases ranging from obesity to cancer, but there have been relatively few investigations of bacteria in surgical diseases of infancy and childhood. In this review, we discuss how novel culture-independent approaches have been harnessed to profile microbes present within clinical specimens. Unique features of the pediatric microbiota and innovative approaches to manipulate the gut flora are also reviewed. Finally, we detail the contributions of gut microbes to 3 diseases relevant to pediatric surgeons: necrotizing enterocolitis, obesity, and inflammatory bowel disease. Current and future research regarding the pediatric microbiota is likely to translate to improved outcomes for infants and children with surgical diseases.

In vitro cow's milk protein-specific inflammatory and regulatory cytokine responses in preterm infants with necrotizing enterocolitis and sepsis

Enteral feeding with cow's milk formula is associated with neonatal necrotizing enterocolitis (NEC) and sepsis. Dietary antigen sensitization may play a role in promoting and/or sustaining inflammation in both conditions. Aiming at investigating cow's milk protein (CMP)-specific cytokine responses in preterm infants with NEC and sepsis, 14 babies with NEC, 14 matched healthy controls, and 10 septic controls were recruited. Unstimulated and stimulated peripheral blood mononuclear cells (PBMCs) secreting IFN-γ, IL-4, IL-10, and TGF-β1 were counted by the single-cell enzyme-linked immunospot (ELISPOT) assay. During the acute phase of NEC, patients showed a general pattern of a high level of cytokine secretion both when unstimulated and stimulated by mitogen [phytohaemagglutinin (PHA)] and CMPs: beta-lactoglobulin (β-lg) and casein. These responses were more marked to β-lg for IFN-γ, IL-4, and IL-10 than TGF-β1. Cytokine responses in sepsis were lower than in NEC (lowest in healthy controls, with a minimal TGF-β1 response). At term, lower frequencies of cytokine-secreting cells were elicited than during the acute phase, except for TGF-β1 secreting cells, which increased at term (in response to PHA and CMPs) particularly following not only NEC but also sepsis.