Human milk composition: nutrients and bioactive factors

Evaluation of colostrum as an alternative biological sample for the diagnosis of human congenital toxoplasmosis

Background

Toxoplasmosis is a zoonosis caused by Toxoplasma gondii, an intracellular protozoan parasite able to infect a wide range of hosts, including humans. Congenital infection can cause severe damage to the fetus. Thus, it is important to detect antibodies against the parasite to confirm clinical manifestations. Considering that all immunoglobulin isotypes may be present in biological samples from newborns and their mothers, this study aimed to evaluate the ability to diagnose recent toxoplasmosis by using colostrum, as an alternative noninvasive way to obtain biological samples, as well as to determine correlation rates between antibodies from serum samples to detect IgG, IgM and IgA isotypes against T. gondii.

Methods

A total of 289 puerperal women from Clinical Hospital of Federal University of Uberlândia (mean age: 24.8 years, range: 14 – 43 years) took part in this study. Serum and colostrum samples from these patients were analyzed using ELISA and immunoblotting assays for soluble antigens from T. gondii.

Results

ELISA immunoassays with serum samples showed reactivity in 47.0, 6.9 and 2.8 % of samples to anti-T. gondii IgG, IgM and IgA, respectively, in comparison with colostrum samples, which showed reactivity in 46.0, 7.9 and 2.8 % of samples to the same isotypes. Also, significant correlation rates of anti-T. gondii antibody levels between serum and colostrum samples were observed. Interestingly, reactivity to IgM and/or IgA in colostrum and/or serum confirmed clinical manifestations of congenital toxoplasmosis in three newborns. Immunoblotting assays showed that it is possible to detect IgG, IgM and IgA antibodies against various antigens of T. gondii in serum and colostrum samples. IgG antibodies in serum and colostrum samples recognized more antigenic fractions than IgM and IgA antibodies. Serum IgG detected more antigenic fractions than IgG antibodies present in the colostrum of the same patient. In contrast, specific IgA present in colostrum recognized a higher number of antigens than IgA present in serum samples of the same patient.

Conclusions

Overall, the results show that it is important to investigate the occurrence of congenital toxoplasmosis, even at puerperal period. Furthermore, this study demonstrates that T. gondii-specific IgG, IgM and IgA antibodies in serum and colostrum samples from puerperal women may be detected with a significant correlation, suggesting that colostrum may also be used as an alternative biological sample to efficiently diagnose recent human toxoplasmosis.

Human breast milk: A review on its composition and bioactivity

Breast milk is the perfect nutrition for infants, a result of millions of years of evolution, finely attuning it to the requirements of the infant. Breast milk contains many complex proteins, lipids and carbohydrates, the concentrations of which alter dramatically over a single feed, as well as over lactation, to reflect the infant's needs. In addition to providing a source of nutrition for infants, breast milk contains a myriad of biologically active components. These molecules possess diverse roles, both guiding the development of the infants immune system and intestinal microbiota. Orchestrating the development of the microbiota are the human milk oligosaccharides, the synthesis of which are determined by the maternal genotype. In this review, we discuss the composition of breast milk and the factors that affect it during the course of breast feeding. Understanding the components of breast milk and their functions will allow for the improvement of clinical practices, infant feeding and our understanding of immune responses to infection and vaccination in infants.

Analysis of Naturally Occurring Steroid Hormones in Infant Formulas by HPLC-MS/MS and Contribution to Dietary Intake

Milk is a natural fluid and as such contains small amounts of naturally occurring steroids. Human milk is recommended as the optimal source of nutrients for infants and young children, and it has been associated to several short- and long-term benefits. For this reason, its composition is used as a reference for designing infant formulas. However, the available information on the hormonal levels of these dairy products is scarce, and it is usually limited to estradiol and estrone. In the present study, six natural sex hormones (pregnenolone, progesterone, estrone, dehydroepiandrosterone, testosterone and androstenedione) have been extracted from sixteen milk-based infant formulas and analyzed with liquid chromatography tandem mass spectrometry (HPLC-MS/MS). The purpose of this research was to quantify natural steroid hormones in various infant formulas, to provide food and nutrition practitioners with information to estimate intakes in children. In addition, data found in the literature was used for comparison. The findings suggest that there are certain similarities between bovine milk and dairy products for infants. Furthermore, the detected levels were in general lower than those observed in human milk and/or colostrum. The reported results represent a valuable addition to the current knowledge on natural hormone content of infant foods.

Newborn intensive care survivors: a review and a plan for collaboration in Texas

BACKGROUND

Neonatal intensive care is a remarkable success story with dramatic improvements in survival rates for preterm newborns. Significant efforts and resources are invested to improve mortality and morbidity but much remains to be learned about the short and long-term effects of neonatal intensive care unit (NICU) interventions. Published guidelines recommend that infants discharged from the NICU be in an organized follow-up program that tracks medical and neurodevelopmental outcomes. Yet, there are no standardized guidelines for provision of follow-up services for high-risk infants. The National Institute of Child Health and Human Development Neonatal Research Network and the Vermont Oxford Network have made strides toward standardizing practices and conducting outcomes research, but only include a subset of developmental follow-up programs with a focus on extremely preterm infants. Several studies have been conducted to gain a better understanding of current practices in developmental follow-up. Some of the major themes in these studies are the lack of personnel and funding to provide comprehensive follow-up care; feeding difficulties as a primary issue for NICU survivors, families, and programs; wide variability in referral and follow-up care practices; and calls for standardized, systematic developmental surveillance to improve outcomes.

FINDINGS

We convened a one-day summit to discuss developmental follow-up practices in Texas involving four academic and three nonacademic centers. All seven centers described variable age and weight criteria for follow-up of NICU patients and a unique set of developmental practices, including duration of follow-up, types and timing of developmental assessments administered, education and communication with families and other health care providers, and referrals for services. Needs identified by the centers focused on two main themes: resources and comprehensive care. Participants identified key challenges for developmental follow-up, generated recommendations to address these challenges, and outlined components of a quality program.

CONCLUSIONS

The long-term goal is to ensure that all children maximize their potential; a goal supported through quality, comprehensive developmental follow-up care and outcomes research to continuously improve evidence-based practices. We aim to contribute to this goal through a statewide working group collaborating on research to standardize practices and inform policies that truly benefit children and their families.

Systematic review of the impact of feed protein type and degree of hydrolysis on gastric emptying in children

Background

The choice of infant formula is thought to play an important role on gastric emptying (GE) in a variety of gastrointestinal disorders. It is known that many ingredients impact on GE, including the type of protein and level of hydrolysis. In clinical practice, feeds are often recommended due to putative improved GE related to the type of protein and level of hydrolysis, however whether this is scientifically justified still needs to be established. A systematic review comparing the impact of protein type and hydrolysis on GE in children was therefore performed.

Methods

The Patient, Intervention, Comparison and Outcome system was used. A structured literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, searching PubMed, Cochrane databases and Google Scholar from 1990 to 2014. We only included articles published in full text English language using specific search terms, including both scintigraphy and C13-octanoic acid breath test.

Results

We identified 126 publications of which 20 were eligible for inclusion but only 8 were included. Studies reviewed GE in both healthy children as well as those with neurodevelopmental delay and reflux. Two studies investigating GE of breast milk versus formula indicated a faster GE for breast milk. Four studies found that feeds containing whole whey in varying amounts emptied faster than predominant whole casein feeds and one study found no difference in GE. Five studies investigated a mix of whole versus hydrolysed protein and found conflicting results related to study population and hydrolysis.

Conclusions

Breast milk has a faster GE than formula milk. Although there seems to be a trend towards whey feeds emptying faster, different methodologies, feed compositions and patient groups makes it difficult to draw firm conclusions. Future studies should be performed with comparable feeds in populations where increased GE may be of clinical benefit.

Influence of Enteral Nutrition on Occurrences of Necrotizing Enterocolitis in Very-Low-Birth-Weight Infants

OBJECTIVE

The aim of the present study was to investigate the influence of enteral feeding management on occurrences of necrotizing enterocolitis (NEC) in very-low-birth-weight (VLBW) infants.

METHODS

This was a case-control study conducted in a sample of 1028 VLBW infants (750 to 1499 g) admitted to a neonatal intensive care unit between January 2003 and May 2008. "Cases" were infants born with VLBW and diagnosed with NEC within the first 30 days of life, and "controls" were VLBW infants who did not develop NEC during this period. Occurrences of NEC were defined using the modified Bell criteria (stage ≥2).

RESULTS

Among the 1028 VLBW infants, 55 (5.4%) developed NEC within the first month of life. Logistic regression analysis showed that breast milk given exclusively for <7 days (odds ratio [OR] = 4.02), never achieving full enteral feeding during the first month (OR = 3.50), and parenteral nutrition (OR = 2.70) were factors that increased the chances of NEC occurrence. The use of vasoactive drugs was associated with a lower risk of NEC (OR = 0.15).

CONCLUSIONS

Breast milk should be recommended as a priority for the enteral nutrition of VLBW infants for no <7 days. Enteral nutrition should start early and progress quickly to achieve full enteral feeding; these procedures may help reduce the occurrence of NEC.

The role of breast-feeding in infant immune system: a systems perspective on the intestinal microbiome

BACKGROUND

The human intestinal microbiota changes from being sparsely populated and variable to possessing a mature, adult-like stable microbiome during the first 2 years of life. This assembly process of the microbiota can lead to either negative or positive effects on health, depending on the colonization sequence and diet. An integrative study on the diet, the microbiota, and genomic activity at the transcriptomic level may give an insight into the role of diet in shaping the human/microbiome relationship. This study aims at better understanding the effects of microbial community and feeding mode (breast-fed and formula-fed) on the immune system, by comparing intestinal metagenomic and transcriptomic data from breast-fed and formula-fed babies.

RESULTS

We re-analyzed a published metagenomics and host gene expression dataset from a systems biology perspective. Our results show that breast-fed samples co-express genes associated with immunological, metabolic, and biosynthetic activities. The diversity of the microbiota is higher in formula-fed than breast-fed infants, potentially reflecting the weaker dependence of infants on maternal microbiome. We mapped the microbial composition and the expression patterns for host systems and studied their relationship from a systems biology perspective, focusing on the differences.

CONCLUSIONS

Our findings revealed that there is co-expression of more genes in breast-fed samples but lower microbial diversity compared to formula-fed. Applying network-based systems biology approach via enrichment of microbial species with host genes revealed the novel key relationships of the microbiota with immune and metabolic activity. This was supported statistically by data and literature.

Lactational changes in concentration and distribution of ganglioside molecular species in human breast milk from Chinese mothers

Gangliosides play a critical role in human brain development and function. Human breast milk (HBM) is an important dietary source of gangliosides for the growing infant. In this study, ganglioside concentrations were measured in the breast milk from a cross-sectional sample of Chinese mothers over an 8-month lactation period. The average total ganglioside concentration increased from 13.1 mg/l during the first month to 20.9 mg/l by 8 months of lactation. The average concentration during the typically solely breast-feeding period of 1‒6 months was 18.9 mg/l. This is the first study to report the relative distribution of the individual ganglioside molecular species through lactation for any population group. The ganglioside molecular species are made up of different fatty acid moieties that influence the physical properties of these gangliosides, and hence affect their function. The GM(3) molecular species containing long-chain acyl fatty acids had the most prominent changes, increasing in both concentration and relative distribution. The equivalent long-chain acyl fatty acid GD(3) molecular species typically decreased in concentration and relative distribution. The lactational trends for both concentration and relative distribution for the very long-chain acyl fatty acid molecular species were more varied. The major GM(3) and GD(3) molecular species during lactation were d40:1 and d42:1, respectively. An understanding of ganglioside molecular species distribution in HBM is essential for accurate application of mass spectrometry methods for ganglioside quantification.

Metabolic products in urine of preterm infants characterized via gas chromatography-mass spectrometry

OBJECTIVE

To characterize the metabolic products of urine associated with preterm birth, thus providing clinical guidelines for intestinal and parenteral nutrition in preterm infants.

METHODS

Urine samples of 47 preterm infants and 45 full-term infants were collected and prepared for trimethylsilylation by treatment with urease. The levels of lysine, phenylalanine, histidine, ornithine, fumaric acid, malic acid, succinic acid, lactose, stearic acid, and 4-hydroxyphenylacetic acid were detected by gas chromatography-mass spectrometry (GC/MS), and statistically analyzed.

RESULTS

The normalized concentrations of the following metabolites in preterm infant urine samples were significantly lower than that of full-term infant urine samples: lysine (P = 0.003), phenylalanine (P = 0.001), histidine (P = 0.006), ornithine (P = 0.000), fumaric acid (P = 0.002), malic acid (P = 0.006), succinic acid (P = 0.000), lactose (P = 0.000), stearic acid (P = 0.000) and 4-hydroxyphenylacetic acid (P = 0.000).

CONCLUSIONS

The results of the GC/MS analysis indicated that amino acid, carbohydrate, and fatty acid metabolism defects exist in preterm infants. The use of GC/MS to determine metabolic products in urine samples could be helpful for prospectively evaluating the nutritional status of preterm infants, and therefore providing clinical guidelines on reasonable nutritional support.

Phylogenetic and Metabolic Tracking of Gut Microbiota during Perinatal Development

The colonization and development of gut microbiota immediately after birth is highly variable and depends on several factors, such as delivery mode and modality of feeding during the first months of life. A cohort of 31 mother and neonate pairs, including 25 at-term caesarean (CS) and 6 vaginally (V) delivered neonates (DNs), were included in this study and 121 meconium/faecal samples were collected at days 1 through 30 following birth. Operational taxonomic units (OTUs) were assessed in 69 stool samples by phylogenetic microarray HITChip and inter- and intra-individual distributions were established by inter-OTUs correlation matrices and OTUs co-occurrence or co-exclusion networks. 1H-NMR metabolites were determined in 70 stool samples, PCA analysis was performed on 55 CS DNs samples, and metabolome/OTUs co-correlations were assessed in 45 CS samples, providing an integrated map of the early microbiota OTUs-metabolome. A microbiota "core" of OTUs was identified that was independent of delivery mode and lactation stage, suggesting highly specialized communities that act as seminal colonizers of microbial networks. Correlations among OTUs, metabolites, and OTUs-metabolites revealed metabolic profiles associated with early microbial ecological dynamics, maturation of milk components, and host physiology.

Higher Fat Content in Breastmilk Expressed Manually: A Randomized Trial

OBJECTIVE

This study aimed to evaluate the effect of milk expression method (manual expression versus electric pump) on the composition of breastmilk.

STUDY DESIGN

Data on 21 mothers of 21 newborns 48-72 hours postdelivery were collected and analyzed. The women were randomly assigned to express breastmilk manually followed by pump, or in reverse order. The fat, carbohydrate, and protein contents of the milk samples were analyzed using a human milk analyzer (Miris AB, Uppsala, Sweden).

RESULTS

The fat and energy contents of milk obtained through manual expression were higher than those obtained by pump (p=0.024 and p=0.04, respectively, by the Wilcoxon signed rank test). There were no significant differences in protein or carbohydrate content of milk obtained by either method of expression. The difference in fat content between milk obtained by the two methods was not correlated with mother's age, delivery method, gestational age at delivery, parity, or the interval between delivery and the time the sampled milk was obtained.

CONCLUSIONS

Manually expressed human milk had higher fat content than milk expressed by electric pump. We speculate that this difference is due to the presence of hindmilk in the manually expressed milk because the technique of massaging the breast during manual expression is more likely than the pump to eject hindmilk, which has been shown to have higher fat content than foremilk.

The Role of Immunonutrients in the Prevention of Necrotizing Enterocolitis in Preterm Very Low Birth Weight Infants

Necrotizing enterocolitis (NEC) is a critical intestinal emergency condition, which mainly occurs in preterm very low birth weight (PVLBW) infants. Despite remarkable advances in the care of PVLBW infants, with considerable improvement of the survival rate in recent decades, the incidence of NEC and NEC-related mortality have not declined accordingly. The fast progression from nonspecific signs to extensive necrosis also makes primary prevention the first priority. Recently, increasing evidence has indicated the important role of several nutrients in primary prevention of NEC. Therefore, the aim of this review is to summarize some potential immunomodulatory nutrients in the prevention of NEC, including bovine colostrum, probiotics, prebiotics (e.g., human milk oligosaccharides), long chain polyunsaturated fatty acids, and amino acids (glutamine, cysteine and N-acetylcysteine, l-arginine and l-citrulline). Based on current research evidence, probiotics are the most documented effective method to prevent NEC, while others still require further investigation in animal studies and clinical randomized controlled trials.

Sensitive detection of major food allergens in breast milk: first gateway for allergenic contact during breastfeeding

Food allergy is recognized as a major public health issue, especially in early childhood. It has been hypothesized that early sensitization to food allergens maybe due to their ingestion as components dissolved in the milk during the breastfeeding, explaining reaction to a food, which has never been taken before. Thus, the aim of this work has been to detect the presence of the food allergens in breast milk by microarray technology. We produced a homemade microarray with antibodies produced against major food allergens. The antibody microarray was incubated with breast milk from 14 women collected from Fundación Jiménez Díaz Hospital. In this way, we demonstrated the presence of major foods allergens in breast milk. The analysis of allergens presented in breast milk could be a useful tool in allergy prevention and could provide us a key data on the role of this feeding in tolerance induction or sensitization in children.

Infant Maturity at Birth Reveals Minor Differences in the Maternal Milk Metabolome in the First Month of Lactation

BACKGROUND

Human milk is the gold standard of nutrition for infants, providing both protective and essential nutrients. Although much is known about milk from mothers giving birth to term infants, less is known about milk from mothers giving birth to premature infants. In addition, little is known about the composition and diversity of small molecules in these milks and how they change over the first month of lactation.

OBJECTIVE

The objective was to understand how milk metabolites vary over the first month of lactation in mothers giving birth to term and preterm infants.

METHODS

(1)H nuclear magnetic resonance (NMR) metabolomics was used to characterize metabolites that were present in micromolar to molar concentrations in colostrum (day 0-5 postpartum), transition milk (day 14), and mature milk (day 28) from mothers who delivered term (n = 15) and preterm (n = 13) infants. Principal components analysis, linear mixed-effects models (LMMs), and linear models (LMs) were used to explore the relation between infant maturity and the postpartum day of collection of milk samples.

RESULTS

By using a standard NMR metabolite library, 69 metabolites were identified in the milks, including 15 sugars, 23 amino acids and derivatives, 11 energy-related metabolites, 10 fatty acid-associated metabolites, 3 nucleotides and derivatives, 2 vitamins, and 5 bacteria-associated metabolites. Many metabolite concentrations followed a similar progression over time in both term and preterm milks, with more biological variation in metabolite concentrations in preterm milk. However, although lacto-N-neotetraose (LMM, P = 4.0 × 10(-5)) and lysine (LM, P = 1.5 × 10(-4)) significantly decreased in concentration in term milk over time, they did not significantly change in preterm milk.

CONCLUSION

Overall, the metabolic profile of human milk is dynamic throughout the first month of lactation, with more variability in preterm than in term milk and subtle differences in some metabolite concentrations. This trial was registered at clinicaltrials.gov as NCT01841268.

Macronutrient composition of human milk from Korean mothers of full term infants born at 37-42 gestational weeks

BACKGROUND/OBJECTIVES

Breast milk is the best available food for optimum growth and development of infants and the breastfeeding rate is increasing in Korea. The purpose of this study is to measure the concentrations of macronutrients and to evaluate their changes according to lactation period in breast milk from lactating Korean women.

SUBJECTS/METHODS

Milk samples were obtained from 2,632 healthy lactating women (mean age; 32.0 ± 3.3 years), where the lactating period was up to a period of 8 months, who also volunteered to participate in the Human Milk Macronutrient Analysis Research. Lactose, protein, fat and water content in the breast milk samples were analyzed with infrared spectrometry using MilkoScan FT-2.

RESULTS

The mean macronutrient composition per 100 mL of mature breast milk was 7.1 g for lactose, 1.4 g for protein and 3.0 g for fat, and energy content was 61.1 kcal. The protein concentration was significantly lower in milk samples at 1-2 weeks (2.0 g/dL) to 2-3 months (1.4 g/dL) than those at 0-1 week (2.2 g/dL), but it was similar among samples from 3-4 months to 7-8 months (1.3 g/dL). Mean lipid levels varied among different lactational period groups (2.7-3.2 g/dL), but presented no significant difference. Lactose concentration in the milk samples did not differ with lactation period. Maternal body mass index was positively related to protein and lipid breast milk contents, but was negatively related to lactose content. General linear models examining the associations between maternal variables and milk macronutrient content revealed that lactation period had a major impact on protein and lipid, but not on lactose content in breast milk.

CONCLUSIONS

These results warrant future studies to explore factors that may be associated with changes in macronutrient content in human milk.

Lactoferrin causes IgA and IgG2b isotype switching through betaglycan binding and activation of canonical TGF-β signaling

Lactoferrin (LF), a pleiotropic iron-binding glycoprotein, is known to modulate the humoral immune response. However, its exact role in Ig synthesis has yet to be elucidated. In this study, we investigated the effect of LF on Ig production by mouse B cells and its underlying mechanisms. LF, like transforming growth factor (TGF)-β1, stimulated B cells to produce IgA and IgG2b, while downregulating other isotypes. Using limiting dilution analysis, LF was shown to increase the frequency of IgA-secreting B-cell clones. This was paralleled by an increase in Ig germ-line α (GLα) transcripts, indicating that LF plays a role as an IgA switch factor. Interestingly, LF directly interacted with betaglycan (TGF-β receptor III, TβRIII) and in turn induced phosphorylation of TβRI and Smad3 through formation of the TβRIII/TβRII/TβRI complex, leading to IgA isotype switching. Peroral administration of LF increased intestinal/serum IgA production as well as number of IgA plasma cells in lamina propria. Finally, we found that LF has an adjuvant activity when nontoxigenic Salmonella typhimurium was inoculated perorally, conferring protection against intragastrical infection of toxigenic S. typhimurium. These results suggest that LF has an important effect on the mucosal/systemic IgA response and can contribute to protection against intestinal pathogens.

Human Milk Warming Temperatures Using a Simulation of Currently Available Storage and Warming Methods

Human milk handling guidelines are very demanding, based upon solid scientific evidence that handling methods can make a real difference in infant health and nutrition. Indeed, properly stored milk maintains many of its unique qualities and continues to be the second and third best infant feeding alternatives, much superior to artificial feeding. Container type and shape, mode of steering, amount of air exposure and storage temperature may adversely affect milk stability and composition. Heating above physiological temperatures significantly impacts nutritional and immunological properties of milk. In spite of this knowledge, there are no strict guidelines regarding milk warming. Human milk is often heated in electrical-based bottle warmers that can exceed 80°C, a temperature at which many beneficial human milk properties disappear. High temperatures can also induce fat profile variations as compared with fresh human milk. In this manuscript we estimate the amount of damage due to overheating during warming using a heat flow simulation of a regular water based bottle warmer. To do so, we carried out a series of warming simulations which provided us with dynamic temperature fields within bottled milk. We simulated the use of a hot water-bath at 80°C to heat bottled refrigerated milk (60 ml and 178 ml) to demonstrate that large milk portions are overheated (above 40°C). It seems that the contemporary storage method (upright feeding tool, i.e. bottle) and bottle warming device, are not optimize to preserve the unique properties of human milk. Health workers and parents should be aware of this problem especially when it relates to sick neonates and preemies that cannot be directly fed at the breast.

Longitudinal Survey of Carotenoids in Human Milk from Urban Cohorts in China, Mexico, and the USA

Emerging evidence indicates that carotenoids may have particular roles in infant nutrition and development, yet data on the profile and bioavailability of carotenoids from human milk remain sparse. Milk was longitudinally collected at 2, 4, 13, and 26 weeks postpartum from twenty mothers each in China, Mexico, and the USA in the Global Exploration of Human Milk Study (n = 60 donors, n = 240 samples). Maternal and neonatal plasma was analyzed for carotenoids from the USA cohort at 4 weeks postpartum. Carotenoids were analyzed by HPLC and total lipids by Creamatocrit. Across all countries and lactation stages, the top four carotenoids were lutein (median 114.4 nmol/L), β-carotene (49.4 nmol/L), β-cryptoxanthin (33.8 nmol/L), and lycopene (33.7 nmol/L). Non-provitamin A carotenoids (nmol/L) and total lipids (g/L) decreased (p<0.05) with increasing lactation stage, except the provitamin A carotenoids α- and β-cryptoxanthin and β-carotene did not significantly change (p>0.05) with lactation stage. Total carotenoid content and lutein content were greatest from China, yet lycopene was lowest from China (p<0.0001). Lutein, β-cryptoxanthin, and β-carotene, and lycopene concentrations in milk were significantly correlated to maternal plasma and neonatal plasma concentrations (p<0.05), with the exception that lycopene was not significantly associated between human milk and neonatal plasma (p>0.3). This enhanced understanding of neonatal exposure to carotenoids during development may help guide dietary recommendations and design of human milk mimetics.

Human, donkey and cow milk differently affects energy efficiency and inflammatory state by modulating mitochondrial function and gut microbiota

Different nutritional components are able, by modulating mitochondrial function and gut microbiota composition, to influence body composition, metabolic homeostasis and inflammatory state. In this study, we aimed to evaluate the effects produced by the supplementation of different milks on energy balance, inflammatory state, oxidative stress and antioxidant/detoxifying enzyme activities and to investigate the role of the mitochondrial efficiency and the gut microbiota in the regulation of metabolic functions in an animal model. We compared the intake of human milk, gold standard for infant nutrition, with equicaloric supplementation of donkey milk, the best substitute for newborns due to its nutritional properties, and cow milk, the primary marketed product. The results showed a hypolipidemic effect produced by donkey and human milk intake in parallel with enhanced mitochondrial activity/proton leakage. Reduced mitochondrial energy efficiency and proinflammatory signals (tumor necrosis factor α, interleukin-1 and lipopolysaccharide levels) were associated with a significant increase of antioxidants (total thiols) and detoxifying enzyme activities (glutathione-S-transferase, NADH quinone oxidoreductase) in donkey- and human milk-treated animals. The beneficial effects were attributable, at least in part, to the activation of the nuclear factor erythroid-2-related factor-2 pathway. Moreover, the metabolic benefits induced by human and donkey milk may be related to the modulation of gut microbiota. In fact, milk treatments uniquely affected the proportions of bacterial phyla and genera, and we hypothesized that the increased concentration of fecal butyrate in human and donkey milk-treated rats was related to the improved lipid and glucose metabolism and detoxifying activities.

Longitudinal analysis of mature breastmilk and serum immune composition among mixed HIV-status mothers and their infants

BACKGROUND & AIMS

Understanding mature breastmilk immunology may benefit infants chronically exposed to infectious pathogens in resource-limited regions.

METHODS

This prospective rural/semi-rural Tanzanian cohort of women (n = 102 at delivery; 38% HIV-positive) and their infants (n = 102) investigated breastmilk, maternal and infant serum immunoglobulins (IgA/IgG1-4/IgM) and cytokines (IL-1β/IL-2/IL-6/IL-10/IL-12p70/IL-13/IL-15/TNF-α/IFN-γ) at 1, 2, 3, 6-months postpartum.

RESULTS

Milk immunoglobulins followed an inverse U-shaped pattern, while cytokine patterns were mixed. Exclusive breastfeeding duration and feeding intensity were associated with greater breastmilk total immunoglobulin and IgA, IgG1-3 and IL-12p70 concentrations. Maternal mastitis, fever or cough was associated with higher breastmilk total cytokine concentrations, while infant fever was associated with lower milk immunoglobulins or cytokines. Strong (r ≥ 0.40) to weak (r = 0.20-0.29) positive correlations between maternal serum-breastmilk or breastmilk-infant serum immunoglobulins were evident. Breastmilk cytokines were moderate to weakly negatively correlated with infant serum. Breastmilk immunology did not differ by maternal malnutrition or HIV-seropositivity.

CONCLUSIONS

Mature breastmilk is a dynamic source of many specific and non-specific immune factors associated with maternal and infant health and infant nutrition. Breastfeeding practices are associated with differential breastmilk immunological composition providing immunological support for universal recommendations to exclusively breastfeed for 6-months.

Randomized controlled trial of lactoferrin for prevention of sepsis in peruvian neonates less than 2500 g

BACKGROUND

Lactoferrin (LF) is a broad-spectrum antimicrobial and immunomodulatory milk glycoprotein.

OBJECTIVE

To determine the effect of bovine LF on the prevention of the first episode of late-onset sepsis in Peruvian infants.

METHODS

We conducted a pilot randomized placebo-controlled double blind study in infants with a birth weight (BW) less than 2500g in 3 Neonatal Units in Lima. Patients were randomized to receive bovine LF 200mg/kg/d or placebo for 4 weeks.

RESULTS

One hundred and ninety neonates with a BW of 1591 ± 408 g and a gestational age of 32.1 ± 2.6 weeks were enrolled. Overall, 33 clinically defined first late-onset sepsis events occurred. The cumulative sepsis incidence in the LF group was 12/95 (12.6%) versus 21/95 (22.1%) in the placebo group, and 20% (8/40) versus 37.5% (15/40) for infants less than or equal to 1500 g. The hazard ratio of LF, after adjustment by BW, was 0.507 (95% CI: 0.249-1.034). There were 4 episodes of culture-proven sepsis in the LF group versus 4 in the placebo group. Considering that children did not received the intervention until the start of oral or tube feeding, we ran a secondary exploratory analysis using time since the start of the treatment; in this model, LF achieved significance. There were no serious adverse events attributable to the intervention.

CONCLUSIONS

Overall sepsis occurred less frequently in the LF group than in the control group. Although the primary outcome did not reach statistical significance, the confidence interval is suggestive of an effect that justifies a larger trial.

Amlodipine passage into breast milk in lactating women with pregnancy-induced hypertension and its estimation of infant risk for breastfeeding

BACKGROUND

Few clinical reports have been published on amlodipine passage into breast milk in lactating women.

OBJECTIVES

The aims of this study were to evaluate the plasma concentration of amlodipine and its passage into breast milk in lactating women with pregnancy-induced hypertension and to estimate the risk for breastfeeding infants.

METHODS

Thirty-one lactating women receiving oral amlodipine once daily for pregnancy-induced hypertension were enrolled. Pre-dose plasma and milk concentrations of amlodipine were determined at day 6 or later after starting the medication. Relative infant dose (RID) as an infant risk for breastfeeding was calculated by dividing the infant dose via milk by the maternal dose.

RESULTS

The mean maternal dose of amlodipine was 6.0 mg. The medians of the plasma and milk concentrations of amlodipine were 15.5 and 11.5 ng/mL, respectively. Interindividual variation was observed in the amlodipine dose and body weight-adjusted milk concentrations (interquartile range [IQR], 96.7-205 ng/mL per mg/kg). The median and IQR of the amlodipine concentration ratio of milk to plasma were 0.85 and 0.74 to 1.08, respectively. The medians of infant birth weight and daily amlodipine dose via milk were 2170 g and 4.2 μg/kg, respectively. The median of the RID of amlodipine was 4.2% (IQR, 3.1%-7.3%).

CONCLUSION

Lactating women with pregnancy-induced hypertension had higher plasma concentrations of amlodipine during the early postpartum period. Oral amlodipine transferred into breast milk at the same level as that of plasma. However, the RID of amlodipine in most patients was less than 10%.

Essential Role for Zinc Transporter 2 (ZnT2)-mediated Zinc Transport in Mammary Gland Development and Function during Lactation

The zinc transporter ZnT2 (SLC30A2) imports zinc into vesicles in secreting mammary epithelial cells (MECs) and is critical for zinc efflux into milk during lactation. Recent studies show that ZnT2 also imports zinc into mitochondria and is expressed in the non-lactating mammary gland and non-secreting MECs, highlighting the importance of ZnT2 in general mammary gland biology. In this study we used nulliparous and lactating ZnT2-null mice and characterized the consequences on mammary gland development, function during lactation, and milk composition. We found that ZnT2 was primarily expressed in MECs and to a limited extent in macrophages in the nulliparous mammary gland and loss of ZnT2 impaired mammary expansion during development. Secondly, we found that lactating ZnT2-null mice had substantial defects in mammary gland architecture and MEC function during secretion, including fewer, condensed and disorganized alveoli, impaired Stat5 activation, and unpolarized MECs. Loss of ZnT2 led to reduced milk volume and milk containing less protein, fat, and lactose compared with wild-type littermates, implicating ZnT2 in the regulation of mammary differentiation and optimal milk production during lactation. Together, these results demonstrate that ZnT2-mediated zinc transport is critical for mammary gland function, suggesting that defects in ZnT2 not only reduce milk zinc concentration but may compromise breast health and increase the risk for lactation insufficiency in lactating women.

Milk bioactives may manipulate microbes to mediate parent-offspring conflict

Among mammals, milk constituents directly influence the ecology of the infant's commensal microbiota. The immunological and nutritional impacts of breast milk and microbiota are increasingly well understood; less clear are the consequences for infant behavior. Here, we propose that interactions among bioactives in mother's milk and microbes in the infant gut contribute to infant behavioral phenotype and, in part, have the potential to mediate parent-offspring conflict. We hypothesize that infant behavior likely varies as a function of their mother's milk composition interacting with the infant's neurobiology directly and indirectly through the commensal gut bacteria. In this article, we will explore our hypothesis of a milk-microbiota-brain-behavior dynamic in the context of the coevolution between human milk oligosaccharides, bacteria, the gut-brain axis and behavior. Integrating established features of these systems allows us to generate novel hypotheses to motivate future research and consider potential implications of current and emerging clinical treatments.

Neonatal nutrition

Optimal nutrition in infancy is the foundation of health in later life. Based on the demonstrated health benefits of human milk, breastfeeding should be the primary means of nutrition for most infants. Although many mothers experience some problems with breastfeeding, health professionals can use simple strategies to overcome most of these problems. For infants who cannot breastfeed, standard infant formulas support adequate nutrition and growth. Gastroesophageal reflux is a common feeding-related event and occurs in most infants; it is part of normal physiology and requires no intervention. Gastroesophageal reflux disease occurs in a small number of infants necessitating the use of an algorithm-based evaluation and management strategy.

The infant gut microbiome: evidence for obesity risk and dietary intervention

Increasing globally, particularly in children, obesity is a serious public health issue and risk factor for overweight and metabolic disease in later life. Both in experimental animal and human studies, advances in gene sequencing technologies have yielded intriguing possibilities for the role of the gut microbiome in later development of overweight status. Before translating study findings into practice, we must first reconcile inconsistencies between animal experimentation, and human adult and infant studies. Recent evidence for associations with gut microbiota and infant weight gain or child weight status, implicate Bacteroides and Lactobacillus species. Dietary manipulation with human milk and pre/probiotic formulations holds promise for preventing obesity.

Administration of a multistrain probiotic product (VSL#3) to women in the perinatal period differentially affects breast milk beneficial microbiota in relation to mode of delivery

Probiotic supplementation to a mother during the perinatal period can have a positive impact on the breast milk composition. The aim of our study was to evaluate the effect of oral supplementation with the probiotic VSL#3, during late pregnancy and lactation, on breast milk levels of beneficial bacteria and some functional components (oligosaccharides and lactoferrin) potentially able to have a positive influence on the microbiota. Breast milk microbiota was analyzed by conventional and quantitative real-time PCR. In a double-blind, placebo-controlled, randomized trial, 66 women took daily either the probiotic (n=33) or a placebo (n=33). Intergroup analysis demonstrated that the amounts of both lactobacilli and bifidobacteria were significantly higher in the colostrum and mature milk of the mothers taking VSL#3 in comparison to those taking placebo. The analysis of bacterial strains and species present in breast milk of VSL#3 supplemented mothers indicated that the administered probiotic microorganisms did not pass from maternal gut to mammary gland. In women with vaginal delivery, significantly higher amounts of lactobacilli and bifidobacteria were detected in colostrum and mature milk of probiotic treated group in comparison to placebo group, whereas no significant difference was observed between groups in women who had caesarean section, neither in colostrum nor in mature milk. Milk levels of oligosaccharides and lactoferrin were similar in placebo and probiotic supplemented groups at all timepoints and regardless of the mode of delivery. Our results indicate a probiotic-dependent modulation of breast milk microbiota in vaginally delivering women, possibly exerted through a systemic effect.

Maternal perinatal undernutrition modifies lactose and serotranferrin in milk: relevance to the programming of metabolic diseases?

A close link between intrauterine growth restriction and development of chronic adult diseases such as obesity, diabetes, and hypertension has been established both in humans and animals. Modification of growth velocity during the early postnatal period (i.e., lactation) may also sensitize to the development of metabolic syndrome in adulthood. This suggests that milk composition may have long-lasting programming/deprogramming metabolic effects in the offspring. We therefore assess the effects of maternal perinatal denutrition on breast milk composition in a food-restricted 50% (FR50) rat model. Monosaccharides and fatty acids were characterized by gas chromatography, and proteins were profiled by surface-enhanced laser desorption/ionization-time-of-flight analysis in milk samples from FR50 and control rat dams. Milk analysis of FR50 rats demonstrated that maternal undernutrition decreases lactose concentration and modulates lipid profile at postnatal day 10 by increasing the unsaturated fatty acids/saturated fatty acids and diminishes serotransferrin levels at postnatal day 21. Our data indicate that maternal perinatal undernutrition modifies milk composition both quantitatively and qualitatively. These modifications by maternal nutrition open new perspectives to identify molecules that could be used in artificial milk to protect from the subsequent development of metabolic diseases.

Milk proteins, peptides, and oligosaccharides: effects against the 21st century disorders

Milk is the most complete food for mammals, as it supplies all the energy and nutrients needed for the proper growth and development of the neonate. Milk is a source of many bioactive components, which not only help meeting the nutritional requirements of the consumers, but also play a relevant role in preventing various disorders. Milk-derived proteins and peptides have the potential to act as coadjuvants in conventional therapies, addressing cardiovascular diseases, metabolic disorders, intestinal health, and chemopreventive properties. In addition to being a source of proteins and peptides, milk contains complex oligosaccharides that possess important functions related to the newborn's development and health. Some of the health benefits attributed to milk oligosaccharides include prebiotic probifidogenic effects, antiadherence of pathogenic bacteria, and immunomodulation. This review focuses on recent findings demonstrating the biological activities of milk peptides, proteins, and oligosaccharides towards the prevention of diseases of the 21st century. Processing challenges hindering large-scale production and commercialization of those bioactive compounds have been also addressed.

Clinical impact of human breast milk metabolomics

Metabolomics is a research field concerned with the analysis of metabolome, the complete set of metabolites in a given cell, tissue, or biological sample. Being able to provide a molecular snapshot of biological systems, metabolomics has emerged as a functional methodology in a wide range of research areas such as toxicology, pharmacology, food technology, nutrition, microbial biotechnology, systems biology, and plant biotechnology. In this review, we emphasize the applications of metabolomics in investigating the human breast milk (HBM) metabolome. HBM is the recommended source of nutrition for infants since it contains the optimal balance of nutrients for developing babies, and it provides a range of benefits for growth, immunity, and development. The molecular mechanisms beyond the inter- and intra-variability of HBM that make its composition unique are yet to be well-characterized. Although still in its infancy, the study of HBM metabolome has already proven itself to be of great value in providing insights into this biochemical variability in relation to mother phenotype, diet, disease, and lifestyle. The results of these investigations lay the foundation for further developments useful to identify normal and aberrant biochemical changes as well as to develop strategies to promote healthy infant feeding practices.

A pilot study on the protein composition of induced nonpuerperal human milk

BACKGROUND

Our understanding of the components of human puerperal milk is extensive and increasing, yet the literature on nonpuerperal human milk has been limited to studies that measure the success of induced lactation.

OBJECTIVE

This study aimed to describe the composition of total protein and key bioactive proteins when lactation is induced in nonpuerperal women.

METHODS

Two women who induced lactation in the absence of pregnancy provided weekly milk samples over a 2-month period for analysis of total protein, secretory immunoglobulin A (sIgA), lysozyme, and lactoferrin. Composition was compared to the mature milk of 3 puerperal control subjects who were 11 months postpartum.

RESULTS

Median total protein for subject A was 2.30 g/dL (interquartile range [IQR] = 0.46) and showed a significant downward trend over time (P < .0001), whereas the median total protein for subject B was 2.21 g/dL (IQR = 0.18) and showed a nonsignificant decline (P = .232). Total protein in both nonpuerperal subjects was elevated compared to control subjects. Secretory IgA activity declined for both nonpuerperal subjects over time, whereas lysozyme concentrations increased over time. Both sIgA and lysozyme approached the levels seen in the puerperal controls. Lactoferrin levels remained stable for both nonpuerperal subjects and were elevated compared to puerperal milk samples.

CONCLUSION

This pilot study suggests that nonpuerperal milk has similar or higher levels of total protein, sIgA, lactoferrin, and lysozyme compared to puerperal, mature milk at 11 months postpartum, which warrants more attention as adoptive mothers increasingly choose to induce lactation.

Influences of breast milk composition on gastric emptying in preterm infants

OBJECTIVES

The aim of the present study was to determine whether specific biochemical and energy concentrations influence gastric emptying of unfortified and fortified mother's own milk (MOM) in stable preterm infants, and whether gastric emptying differs between feeds of unfortified MOM and feeds fortified with S-26 or FM 85 human milk fortifier (HMF) when infants are fed the same volume under similar conditions. Influences of infant gestation, age, and weight, and feed characteristics were also explored.

METHODS

Stomach volumes of 25 paired unfortified and fortified MOM feeds were monitored prefeed and postfeed delivery and at 30-minute intervals thereafter. For each feed, MOM samples were analyzed to determine concentrations of total protein, casein, whey, carbohydrate, lactose, fat, and energy. Fortified feed compositions were calculated by adding fortifier biochemical and energy concentrations to unfortified MOM concentrations. Ultrasound images were used to calculate infant stomach volumes. Statistical comparisons were made of paired stomach volume measurements.

RESULTS

Higher feed concentrations of casein were associated with faster gastric emptying during feed delivery (P = 0.007). When compared with unfortified MOM, S-26 fortified feeds emptied similarly, whereas FM 85 fortified feeds emptied more slowly both during feed delivery and during the postprandial period (P = 0.002, <0.001, respectively). Gastric emptying was slower for 2-hourly feeds compared with that for 3-hourly feeds (P = 0.003) and in supine position compared with that in prone (P = 0.001).

CONCLUSIONS

Breast milk composition influences gastric emptying in stable preterm infants, with feeds of higher casein concentration emptying faster during feeding than otherwise equivalent feeds, and FM 85 fortified MOM emptying more slowly than unfortified MOM.

Epidermal growth factor containing culture supernatant enhances intestine development of early-weaned pigs in vivo: potential mechanisms involved

We have previously generated epidermal factor expressing Lactococcus lactis (EGF-LL) using a bioengineering approach, and shown that EGF-LL fermentation supernatant enhanced newly weaned pigs growth. The objective of the current study was to further understand the mechanisms behind this improved performance. Sixty-four piglets were weaned at 3 weeks of age and then fed ad libitum according to a 2-phase feeding program. Four pens with 8 pigs per pen were assigned to each of two treatments for 3 weeks: (1) EGF containing supernatant from EGF-LL culture (SuperEGF) or (2) blank M17GE media (Control). Consistent with previous findings, SuperEGF pigs had an increased average daily gain during week 3 post-weaning (433.4 ± 10.86 vs 388.7 ± 7.76 g; P<0.05) and overall gain:feed ratio (0.757 ± 0.03 vs 0.677 ± 0.01 kg/kg, P < 0.05). Moreover, jejunal structure development was enhanced, and inflammation index was minimized in SuperEGF pigs as indicated by increased villi height (P<0.05), decreased lamina propria width (P<0.05), and higher expression of anti-inflammatory cytokine, IL-13 (P<0.05). Further, goblet cell numbers and Muc2 levels were increased in SuperEGF pigs. Interestingly, the weaning-induced decrease of glucose cotransporter sodium-glucose linked transporter 1 (SGLT1) and glucagon-like peptide-2 (GLP2) levels was reversed by SuperEGF supplementation. Our findings add to our understanding of the mechanisms behind enhancing piglet performance by EGF containing fermentation product.

Determination of hyaluronan molecular mass distribution in human breast milk

Hyaluronan (HA) in human milk mediates host responses to microbial infection via TLR4- and CD44-dependent signaling. Signaling by HA is generally size specific. Because pure HA with average molecular mass (M) of 35 kDa can elicit a protective response in intestinal epithelial cells, it has been proposed that human milk HA may have a bioactive low-M component. Here we report the size distribution of HA in human milk samples from 20 unique donors. A new method for HA analysis, employing ion exchange (IEX) chromatography to fractionate HA by size and specific quantification of each size fraction by competitive enzyme-linked sorbent assay (ELSA), was developed. When separated into four fractions, milk HA with M⩽20 kDa, M∼20 to 60 kDa, and M∼60 to 110 kDa comprised averages of 1.5, 1.4, and 2.0% of the total HA, respectively. The remaining 95% was HA with M⩾110 kDa. Electrophoretic analysis of the higher M HA from 13 samples showed nearly identical M distributions, with an average M of approximately 440 kDa. This higher M HA component in human milk is proposed to bind to CD44 and to enhance human beta defensin 2 (HBD2) induction by the low-M HA components.

β-defensin-2 in breast milk displays a broad antimicrobial activity against pathogenic bacteria

OBJECTIVE

To describe the antimicrobial activity of β-defensin-2 produced in the mammary gland and secreted in human breast milk.

METHODS

The peptide production was performed by DNA cloning. β-defensin-2 levels were quantified in 61 colostrum samples and 39 mature milk samples from healthy donors, by an indirect enzyme-linked immunosorbent assay (ELISA). Using halo inhibition assay, this study assessed activity against seven clinical isolates from diarrheal feces of children between 0 and 2 years of age. The activity of β-defensin-2 against three opportunistic pathogens that can cause nosocomial infections was determined by microdilution test.

RESULTS

The peptide levels were higher in colostrum (n=61) than in mature milk samples (n=39), as follows: median and range, 8.52 (2.6-16.3) μg/ml versus 0.97 (0.22-3.78), p<0.0001; Mann-Whitney test. The recombinant peptide obtained showed high antimicrobial activity against a broad range of pathogenic bacteria. Its antibacterial activity was demonstrated in a disk containing between 1-4 μg, which produced inhibition zones ranging from 18 to 30 mm against three isolates of Salmonella spp. and four of E. coli. β-defensin-2 showed minimum inhibitory concentrations (MICs) of 0.25 μg/mL and 0.5 μg/mL for S. marcescen and P. aeruginosa, respectively, while a higher MIC (4 μg/mL) was obtained against an isolated of multidrug-resistant strain of A. baumannii.

CONCLUSIONS

To the authors' knowledge, this study is the first to report β-defensin-2 levels in Latin American women. The production and the activity of β-defensin-2 in breast milk prove its importance as a defense molecule for intestinal health in pediatric patients.

Human Milk Oligosaccharides (HMOS): Structure, Function, and Enzyme-Catalyzed Synthesis

The important roles played by human milk oligosaccharides (HMOS), the third major component of human milk, in the health of breast-fed infants have been increasingly recognized, as the structures of more than 100 different HMOS have now been elucidated. Despite the recognition of the various functions of HMOS as prebiotics, antiadhesive antimicrobials, and immunomodulators, the roles and the applications of individual HMOS species are less clear. This is mainly due to the limited accessibility to large amounts of individual HMOS in their pure forms. Current advances in the development of enzymatic, chemoenzymatic, whole-cell, and living-cell systems allow for the production of a growing number of HMOS in increasing amounts. This effort will greatly facilitate the elucidation of the important roles of HMOS and allow exploration into the applications of HMOS both as individual compounds and as mixtures of defined structures with desired functions. The structures, functions, and enzyme-catalyzed synthesis of HMOS are briefly surveyed to provide a general picture about the current progress on these aspects. Future efforts should be devoted to elucidating the structures of more complex HMOS, synthesizing more complex HMOS including those with branched structures, and developing HMOS-based or HMOS-inspired prebiotics, additives, and therapeutics.

Bacteriological, biochemical, and immunological properties of colostrum and mature milk from mothers of extremely preterm infants

OBJECTIVES

The objective of this work was to elucidate the influence of extremely premature birth (gestational age 24-27 weeks) on the microbiological, biochemical, and immunological composition of colostrum and mature milk.

METHODS

A total of 17 colostrum and 34 mature milk samples were provided by the 22 mothers of extremely preterms who participated in this study. Bacterial diversity was assessed by culture-based methods, whereas the concentration of lactose, glucose, and myo-inositol was determined by a gas chromatography procedure. Finally, the concentrations of a wide spectrum of cytokines, chemokines, growth factors, and immunoglobulins were measured using a multiplex system.

RESULTS

Bacteria were present in a small percentage of the colostrum and milk samples. Staphylococci, streptococci, and lactobacilli were the main bacterial groups isolated from colostrum, and they could be also isolated, together with enterococci and enterobacteria, from some mature milk samples. The colostrum concentrations of lactose and glucose were significantly lower than those found in mature milk, whereas the contrary was observed in relation to myo-inositol. The concentrations of most cytokines and immunoglobulins in colostrum were higher than in mature milk, and the differences were significant for immunoglobulin G₃, immunoglobulin G₄, interleukin (IL)-6, interferon-γ, interleukin-4 (IL-4), IL-13, IL-17, macrophage-monocyte chemoattractant protein-1 and macrophage inflammatory protein-1β.

CONCLUSIONS

The bacteriological, biochemical, and immunological content of colostrum and mature milk from mothers of extremely preterm infants is particularly valuable for such infants. Efforts have to be made to try that preterm neonates receive milk from their own mothers or from donors matching, as much as possible, the gestational age of the preterm.