Correction to "Bioactive Peptides in Preterm Human Milk: Impact of Maternal Characteristics and Their Association to Neonatal Outcomes".

Human milk adipokines in term babies seem partially determined by maternal factors and affect infant's development. We aimed to describe bioactive peptide concentration in very preterm human milk and associations to maternal characteristics and postnatal growth. Mothers delivering ≤32 weeks of gestation and their infant/s were recruited. At 4 weeks of lactation, an aliquot of 24-h-pooled milk was collected for exclusively breastfeeding dyads. Insulin, leptin, adiponectin, and milk fat globule epidermal growth factor-8 (MFG-E8) were measured by enzyme-linked immunoabsorbent assay in skimmed milk. One hundred mothers (28.8 ± 2.3 weeks at delivery) provided a milk sample. Milk insulin was related to gestational age, pre-pregnancy body mass index (BMI), and galactagogue treatment (final model: adjusted R2 : 0.330, p < 0.0001; adjusted β coefficients: galactagogue treatment: 0.348, p 0.001; pre-pregnancy BMI: 0.274, p 0.009; gestational age: -0.290, p 0.007). Adiponectin was higher in mothers with gestational diabetes (30.7 ± 6.5 vs. 24.8 ± 8 ng/mL, p 0.044). Leptin was associated with pre-pregnancy BMI (Spearman's ρ: 0.648, p < 0.0001) and MFG-E8 to presence of labor and multiple pregnancy (final linear regression model, R2 : 0.073, p 0.028, adjusted β coefficients: presence of labor -0.229, p 0.050; twins: -0.192, p 0.099). Milk adiponectin was associated with a greater decrease in length z-scores from birth to 28 days (Pearson's r: -0.225, p 0.032) and to discharge (Pearson's r: -0.290, p 0.003). Milk MFG-E8 was lower in milk of mothers whose babies experienced late-onset sepsis (13.3 ± 5.8 vs. 16.8 ± 6.3 μg/mL, p 0.023). Adipokines levels in preterm human milk are partially related to maternal metabolic status. Milk peptide concentration associates with early neonatal growth trajectories.

In vivo endogenous proteolysis yielding beta-casein derived bioactive beta-casomorphin peptides in human breast milk for infant nutrition.

Preterm human breast milk, compared with artificial formula milk, may provide insufficient nutrition for preterm or low birth weight infants. However, human milk may confer advantages in terms of a decreased incidence of gastrointestinal and neurodevelopmental adverse outcomes. To determine if formula milk compared with preterm human milk leads to improved growth and development without significant adverse effects in preterm or low birth weight infants. The standard search strategy of the Cochrane Neonatal Review Group was used. This included electronic searches of the Cochrane Controlled Trials Register, MEDLINE, EMBASE and previous reviews including cross references. Randomised controlled trials comparing feeding with formula milk versus preterm human milk in preterm or low birth weight infants. Data were extracted using the standard methods of the Cochrane Neonatal Review Group, with separate evaluation of trial quality and data extraction by each author and synthesis of data using relative risk and mean difference. Only one small trial fulfilled the pre-specified inclusion criteria (Gross 1983). In preterm and low birth weight infants, enteral feeding with protein-enriched standard calorie formula milk compared with unfortified donated preterm human milk resulted in a greater rate of short term weight gain, but not of increase in length or head circumference. In the group randomised to receive formula milk, there was an increase in the risk of feed intolerance of borderline statistical significance, but no evidence of an effect on necrotising enterocolitis. There are no data on long term growth parameters or on neurodevelopmental outcomes. There are no randomised comparisons of feeding with the preterm milk of the infant's mother versus formula milk. There are very limited data from randomised trials of feeding preterm or low birth weight infants with formula milk compared with preterm human milk. This may relate to a perceived difficulty of allocating an alternative enteral feed to an infant in cases where the infant's mother wishes to feed with expressed breast milk.

Aim: Neonates are notably vulnerable, however they have improved outcomes if they are fed human milk. Human milk lipids constitute the primary constituents of human milk and serve a pivotal role in safeguarding infants from diseases. We assessed the lipid differences between preterm and term human milk and predicted the prospective impacts of these lipids on the development of neonates.Methods and results: We collected colostrum from healthy breast-feeding mothers who had delivered either term or preterm infants. We analyzed the lipid profiles of preterm, as well as term human milk using an LC-MS/MS metabolomics strategy. The orthogonal partial least-squares discriminant analysis score plots revealed remarkable distinction of lipids in preterm and term human milk. In total, 16 subclasses of 235 differential lipids (variable importance in projection > 1, P < 0.05) were identified. Notably, phosphatidylethanolamine and phosphatidylcholine were robustly increased in preterm human milk, while diacylglycerol and ceramide were markedly decreased in preterm human milk. Pathway analysis revealed that these dysregulated lipids are closely associated with glycerophospholipid metabolism, sphingolipid metabolism, Reelin signaling in neurons, and LXR/RXR activation.Conclusion: The results show that the lipids in preterm and term human colostrum vary, which may be critical for neonatal development.

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

Using capillary gas chromatography, we analyzed the fatty acid composition of human milk from 23 women who had delivered prematurely and 16 women who had delivered at term. Milk samples were obtained at 1, 2, 4, 12, and 26 weeks after delivery. The relative amounts of saturated and monounsaturated fatty acids in preterm and term milk remained stable throughout the 6 months of lactation. The proportions of linoleate (18:2n‐6) and α‐linolenate (18:3n‐3) were similar in preterm and term milk and showed an increasing trend from transitional (8.7–9.9% and 0.9–1.1% of total fatty acids, respectively) to mature milk (9.9–11.8% and 1.2–1.5%, respectively). The proportions of the major long‐chain polyun‐saturated fatty acids (LCP), 20:3n‐6, 20:4n‐6, 22:5n‐3 and 22:6n‐3, were highest at 1 week and decreased thereafter in both types of milk. In term milk, the proportion of LCP continued to decrease from 1 month to 6 months, whereas in preterm milk it was fairly constant. Consequently, at 6 months of lactation, the relative content of arachidonate (20:4n‐6) was 1.5 times (p &lt; 0.05) and that of docosa‐hexaenoate (22:6n‐3) was two times higher (p &lt; 0.01) in preterm than in term milk. We conclude that in long‐term lactation, preterm human milk provides a significantly higher relative supply of LCP than term human milk. This higher LCP content may be of special benefit to the development of a preterm infant.

Using capillary gas chromatography, we analyzed the fatty acid composition of human milk from 23 women who had delivered prematurely and 16 women who had delivered at term. Milk samples were obtained at 1, 2, 4, 12, and 26 weeks after delivery. The relative amounts of saturated and monounsaturated fatty acids in preterm and term milk remained stable throughout the 6 months of lactation. The proportions of linoleate (18:2n-6) and alpha-linolenate (18:3n-3) were similar in preterm and term milk and showed an increasing trend from transitional (8.7-9.9% and 0.9-1.1% of total fatty acids, respectively) to mature milk (9.9-11.8% and 1.2-1.5%, respectively). The proportions of the major long-chain polyunsaturated fatty acids (LCP), 20:3n-6, 20:4n-6, 22:5n-3 and 22:6n-3, were highest at 1 week and decreased thereafter in both types of milk. In term milk, the proportion of LCP continued to decrease from 1 month to 6 months, whereas in preterm milk it was fairly constant. Consequently, at 6 months of lactation, the relative content of arachidonate (20:4n-6) was 1.5 times (p < 0.05) and that of docosahexaenoate (22:6n-3) was two times higher (p < 0.01) in preterm than in term milk. We conclude that in long-term lactation, preterm human milk provides a significantly higher relative supply of LCP than term human milk. This higher LCP content may be of special benefit to the development of a preterm infant.

Effect of storage time and temperature on folacin and vitamin C levels in term and preterm human milk

Temporal changes of major protein concentrations in preterm and term human milk. A prospective cohort study

Background: Mother’s own milk is the optimal source of nutrients and provides numerous health advantages for mothers and infants. As they have supplementary nutritional needs, very preterm infants may require fortification of human milk (HM). Addressing HM composition and variations is essential to optimize HM fortification strategies for these vulnerable infants. Aims: To analyze and compare macronutrient composition in HM of mothers lactating very preterm (PT) (28 0/7 to 32 6/7 weeks of gestational age, GA) and term (T) infants (37 0/7 to 41 6/7 weeks of GA) over time, both at similar postnatal and postmenstrual ages, and to investigate other potential factors of variations. Methods: Milk samples from 27 mothers of the PT infants and 34 mothers of the T infants were collected longitudinally at 12 points in time during four months for the PT HM and eight points in time during two months for the T HM. Macronutrient composition (proteins, fat, and lactose) and energy were measured using a mid-infrared milk analyzer, corrected by bicinchoninic acid (BCA) assay for total protein content. Results: Analysis of 500 HM samples revealed large inter- and intra-subject variations in both groups. Proteins decreased from birth to four months in the PT and the T HM without significant differences at any postnatal time point, while it was lower around term equivalent age in PT HM. Lactose content remained stable and comparable over time. The PT HM contained significantly more fat and tended to be more caloric in the first two weeks of lactation, while the T HM revealed higher fat and higher energy content later during lactation (three to eight weeks). In both groups, male gender was associated with more fat and energy content. The gender association was stronger in the PT group, and it remained significant after adjustments. Conclusion: Longitudinal measurements of macronutrients compositions of the PT and the T HM showed only small differences at similar postnatal stages in our population. However, numerous differences exist at similar postmenstrual ages. Male gender seems to be associated with a higher content in fat, especially in the PT HM. This study provides original information on macronutrient composition and variations of HM, which is important to consider for the optimization of nutrition and growth of PT infants.

Endogenous Human Milk Peptide Release Is Greater after Preterm Birth than Term Birth1–3

BackgroundReducing the disposal of donated human milk (HM) is important for efficient management of human milk banks (HMBs). The presence of bacteria growth is the main factor that contributes to the disposal of donated HM. The bacterial profile in HM is suspected to differ between term and preterm mothers, with HM from preterm mothers containing more bacteria. Thus, elucidation of the causes of bacterial growth in preterm and term HM may help to reduce the disposal of donated preterm HM. This study compared the bacterial profiles of HM between mothers of term infants and mothers of preterm infants.MethodsThis pilot study was conducted in the first Japanese HMB, which was initiated in 2017. This study analyzed 214 human milk samples (term: 75, preterm: 139) donated by 47 registered donors (term: 31, preterm: 16) from January to November 2021. Bacterial culture results in term and preterm HM were retrospectively reviewed in May 2022. Differences in total bacterial count and bacterial species count per batch were analyzed using the Mann–Whitney U test. Bacterial loads were analyzed using the Chi-square test or Fisher’s exact test.ResultsThe disposal rate did not significantly differ between term and preterm groups (p = 0.77), but the total amount of disposal was greater in the preterm group (p < 0.01). Coagulase-negative Staphylococci, Staphylococcus aureus, and Pseudomonas fluorescens were frequently found in both types of HM. Serratia liquefaciens (p < 0.001) and two other bacteria were present in term HM; a total of five types of bacteria, including Enterococcus faecalis and Enterobacter aerogenes (p < 0.001) were present in preterm HM. The median (interquartile range) total bacterial counts were 3,930 (435–23,365) colony-forming units (CFU)/mL for term HM and 26,700 (4,050–334,650) CFU/mL for preterm HM (p < 0.001).ConclusionsThis study revealed that HM from preterm mothers had a higher total bacterial count and different types of bacteria than HM from term mothers. Additionally, preterm infants can receive nosocomial-infection-causing bacteria in the NICU through their mother’s milk. Enhanced hygiene instructions for preterm mothers may reduce the disposal of valuable preterm human milk, along with the risk of HM pathogen transmission to infants in NICUs.

Vitamins and carotenoids in human milk delivering preterm and term infants: Implications for preterm nutrient requirements and human milk fortification strategies.

Macronutrient composition in human milk from mothers of preterm and term neonates is highly variable during the lactation period

Breast milk represents nature’s best mechanism to provide complete nourishment and protection to the newborn. Human breast milk acts as a store house of an array of bioactive factors, which includes antimicrobial proteins and antimicrobial peptides that confer early protection while lowering the incidence of developing various infections and exhibiting immune modulation property to activate the immune cells to fight against the invading pathogens. Among the bioactive peptides, endogenous peptides present in breast milk have opened a new window of research on studying their unique mechanisms of action. This will help in incorporating these peptides in formula milk for meeting special needs where breastfeeding is not possible. The present chapter aims to give a deep insight into the various antimicrobial peptides and the newly reported endogenous peptides in human breast milk with emphasis on their levels and activity in preterm milk as data related to this is lacking and preterm newborns are highly vulnerable to acquire infections. Further, the chapter focuses on highlighting the antibacterial mechanisms adopted by the bioactive peptides for protection against the neonatal bacterial pathogens with special emphasis on the infections caused by resistant bacterial strains in hospital settings (neonatal wards) and their future implications.