Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Human Breast Milk Exosomes: Affecting Factors, Their Possible Health Outcomes, and Future Directions in Dietetics

Background: Human breast milk is a complex biological fluid containing multifaceted biological compounds that boost immune and metabolic system development that support the short- and long-term health of newborns. Recent literature suggests that human breast milk is a substantial source of nutrients, bioactive molecules, and exosomes. Objectives: This review examines the factors influencing exosomes noted in human milk and the impacts of exosomes on infant health. Furthermore, it discusses potential future prospects for exosome research in dietetics. Methods: Through a narrative review of the existing literature, we focused on exosomes in breast milk, exosome components and their potential impact on exosome health. Results: Exosomes are single-membrane extracellular vesicles of endosomal origin, with an approximate radius of 20-200 nm. They are natural messengers that cells secrete to transport a wide range of diverse cargoes, including deoxyribonucleic acid, ribonucleic acid, proteins, and lipids between various cells. Some studies have reported that the components noted in exosomes in human breast milk could be transferred to the infant and cause epigenetic changes. Thus, it can affect gene expression and cellular event regulation in several tissues. Conclusions: In this manner, exosomes are associated with several pathways, including the immune system, oxidative stress, and cell cycle, and they can affect the short- and long-term health of infants. However, there is still much to learn about the functions, effectiveness, and certain impacts on the health of human breast milk exosomes.

Lactoferrin Supplementation in Preventing and Protecting from SARS-CoV-2 Infection: Is There Any Role in General and Special Populations? An Updated Review of Literature

At the beginning of the pandemic, SARS-CoV-2 infection represented a great medical burden worldwide, as targeted and effective therapeutic options were lacking. This resulted in the revival of existing molecules and the increasing popularity of over-the-counter nutritional supplements. Among the latter, lactoferrin has been investigated as an adjuvant in COVID-19 therapy with conflicting results, mainly depending on different study designs. Considering that lactoferrin is one of the main components of human breast milk with anti-microbial and anti-inflammatory activity, it is conceivable that such bioactive molecule could be effective in supporting anti-SARS-CoV-2 infection therapy, especially in infants and pregnant women, two subpopulations that have been poorly evaluated in the existing clinical trials. This narrative review is intended to offer insight into the existing literature on lactoferrin's biological functions and protective effects against COVID-19, with a special focus on pregnant women and their infants.

The Role of Breastmilk in Macrophage-Tumour Cell Interactions in Postpartum Breast Cancer

BACKGROUND

Lactation is associated with long-term reduced risk of breast cancer. However, there is a transient increased risk of breast cancer in the 5 to 10 years postpartum and this is associated with a high incidence of metastasis and mortality. Breastmilk is a physiological fluid secreted by the mammary glands intimately connected with breast cells and the microenvironment that may affect postpartum breast cancer development and progression. This study aims to investigate the effect of breastmilk on interactions between breast cancer cells and macrophages in vitro.

METHODS

Human breastmilk from healthy donors (n = 7) was pooled and incubated with breast cancer (MCF-7 and MDA-MB-231) and macrophage (RAW264.7) cell lines to assess cell proliferation, viability, migration, and expression of key genes associated with epithelial-mesenchymal transition (EMT) and macrophage phenotype. Indirect co-culture studies assessed the effect of breastmilk on interactions between breast cancer cells and macrophages.

RESULTS

Breastmilk increased the proliferation and viability of breast cancer cells, reduced EMT markers, and reduced cell migration in MDA-MB-231 cells. Breastmilk decreased mRNA expression of interleukin 1B (IL1B) and interleukin 10 (IL10) in macrophages. Reduced EMT marker expression was observed in breast cancer cells co-cultured with macrophages pre-treated with breastmilk. Macrophages co-cultured with breast cancer cells pre-treated with breastmilk exhibited increased expression of a pro-inflammatory cytokine tumor necrosis factor A (TNFA) and pro-inflammatory nitric oxide synthase 2 (NOS2), and reduced expression of cytokines IL10 and transforming growth factor B1 (TGFB1) which are associated with the alternatively-activated macrophage phenotype.

CONCLUSIONS

Breastmilk has the potential to promote breast cancer proliferation, however, it can also reduce breast cancer progression through inhibition of breast cancer cell migration and regulation of macrophage polarisation. These findings suggest that breastmilk has potential to shape the tumour microenvironment in postpartum breast cancer.

The interaction of breastfeeding and genetic factors on childhood obesity

Childhood obesity represents a pressing global public health concern due to its widespread prevalence and its close connection to early-life exposure to risk factors. The onset of obesity is contingent upon the interplay of genetic composition, lifestyle choices, and environmental as well as nutritional elements encountered during both fetal development and early childhood. This paper critically examines research discoveries in this area and concisely outlines the influence of breastfeeding on genetic predispositions associated with childhood obesity. Studies have demonstrated that breastfeeding has the potential to reduce childhood obesity by impacting anthropometric indicators. Moreover, the duration of breastfeeding is directly correlated with the degree to which it alters the risk of childhood obesity. Current explorations into the link between genetic factors transmitted through breast milk and childhood obesity predominantly focus on genes like FTO, Leptin, RXRα, PPAR-γ, and others. Numerous research endeavors have suggested that an extended period of exclusive breastfeeding is tied to a diminished likelihood of childhood obesity, particularly if sustained during the initial six months. The duration of breastfeeding also correlates with gene methylation, which could serve as the epigenetic mechanism underpinning breastfeeding's preventative influence against obesity. In summary, the thorough evaluation presented in this review underscores the intricate nature of the association between breastfeeding, genetic factors, and childhood obesity, providing valuable insights for future research efforts and policy formulation.

Breastfeeding may reduce the effects of maternal smoking on lung cancer mortality in adult offspring: a prospective cohort study

BACKGROUND

Although previous research has indicated a correlation between smoking and the mortality rate in patients with lung cancer, the impact of early life factors on this relationship remains unclear and requires further investigation. This study aimed to investigate the hypothesis that breastfeeding reduces the risk of lung cancer-related death.

METHODS

The authors conducted a prospective cohort study involving 501 859 participants recruited from the United Kingdom Biobank to explore the potential association between breastfeeding and the risk of lung cancer mortality using a Cox proportional hazards model. Subsequently, the polygenic risk score for lung cancer was calculated to detect interactions between genes and the environment.

RESULTS

Over a median follow-up duration of 11.8 years, encompassing a total of 501 859 participants, breastfeeding was found to reduce the risk of lung cancer-related death and the impact of maternal smoking on lung cancer mortality in adult offspring. This association remained consistent after stratification. Furthermore, the influence of maternal smoking and breastfeeding on the risk of lung cancer mortality was significant at a high genetic risk level.

CONCLUSION

Breastfeeding can reduce the risk of lung cancer-related death and the impact of maternal smoking on lung cancer mortality in adult offspring. This correlation has the potential to reduce the probability of lung-cancer-related deaths in subsequent generations.

Nutrition and the gut-brain axis in neonatal brain injury and development

Early nutritional exposures, including during embryogenesis and the immediate postnatal period, affect offspring outcomes in both the short- and long-term. Alterations of these modifiable exposures shape the developing gut microbiome, intestinal development, and even neurodevelopmental outcomes. A gut-brain axis exists, and it is intricately connected to early life feeding and nutritional exposures. Here, we seek to discuss the (1) origins of the gut-brain access and relationship with neurodevelopment, (2) components of human milk (HM) beyond nutrition and their role in the developing newborn, and (3) clinical application of nutritional practices, including fluid management and feeding on the development of the gut-brain axis, and long-term neurodevelopmental outcomes. We conclude with a discussion on future directions and unanswered questions that are critical to provide further understanding and insight into how clinicians and healthcare providers can optimize early nutritional practices to ensure children not only survive, but thrive, free of neurodevelopmental impairment.

Risk of Fat Mass- and Obesity-Associated Gene-Dependent Obesogenic Programming by Formula Feeding Compared to Breastfeeding

It is the purpose of this review to compare differences in postnatal epigenetic programming at the level of DNA and RNA methylation and later obesity risk between infants receiving artificial formula feeding (FF) in contrast to natural breastfeeding (BF). FF bears the risk of aberrant epigenetic programming at the level of DNA methylation and enhances the expression of the RNA demethylase fat mass- and obesity-associated gene (FTO), pointing to further deviations in the RNA methylome. Based on a literature search through Web of Science, Google Scholar, and PubMed databases concerning the dietary and epigenetic factors influencing FTO gene and FTO protein expression and FTO activity, FTO's impact on postnatal adipogenic programming was investigated. Accumulated translational evidence underscores that total protein intake as well as tryptophan, kynurenine, branched-chain amino acids, milk exosomal miRNAs, NADP, and NADPH are crucial regulators modifying FTO gene expression and FTO activity. Increased FTO-mTORC1-S6K1 signaling may epigenetically suppress the WNT/β-catenin pathway, enhancing adipocyte precursor cell proliferation and adipogenesis. Formula-induced FTO-dependent alterations of the N6-methyladenosine (m6A) RNA methylome may represent novel unfavorable molecular events in the postnatal development of adipogenesis and obesity, necessitating further investigations. BF provides physiological epigenetic DNA and RNA regulation, a compelling reason to rely on BF.

Differential Digestive Stability of Food-Derived microRNAs: The Case of miR-30c-5p and miR-92a-3p in Polyfloral Honey

Dietary microRNAs (miRs) represent a new area in food science. Although they have been found in many foods, including honey, more research is needed about their stability and fate during digestion. Hence, this study aimed to analyze the digestive stability of two selected miRs in honey. We extracted miR-92a-3p and miR-30c-5p from pasteurized and unpasteurized forms of polyfloral honey using two different methods and kits: a column-based manual method and a phenol-free semi-automated magnetic-bead-based method. The latter option was used for the subsequent analysis of samples according to the INFOGEST static in vitro digestion protocol. Also, the honey samples were examined for exosome-like particles using dynamic light scattering. Although the expression levels of both miRs were significantly lower following intestinal digestion, we found a difference in the resilience of the miRs to gastrointestinal conditions, with miR-30c-5p being relatively stable compared to miR-92a-3p following digestion, regardless of the honey's pasteurization treatment. Moreover, there was marked heterogeneity in the extracellular vesicle profile of the pasteurized sample. We identified the presence of two broadly conserved miRs in honey: miR-92a-3p and miR-30c-5p. Despite honey exhibiting high digestibility, miR-92a-3p was less resilient than miR-30c-5p, demonstrating considerable resistance under gastrointestinal conditions. Although further research is needed, the results obtained from this study may represent a starting point for utilizing honey as a source of exogenous miRNAs for preventive strategies and more "natural" treatments.

Fetal programming and lactation: modulating gene expression in response to undernutrition during intrauterine life

BACKGROUND

Adverse environmental conditions during intrauterine life, known as fetal programming, significantly contribute to the development of diseases in adulthood. Fetal programming induced by factors like maternal undernutrition leads to low birth weight and increases the risk of cardiometabolic diseases.

METHODS

We studied a rat model of maternal undernutrition during gestation (MUN) to investigate gene expression changes in cardiac tissue using RNA-sequencing of day 0-1 litters. Moreover, we analyzed the impact of lactation at day 21, in MUN model and cross-fostering experiments, on cardiac structure and function assessed by transthoracic echocardiography, and gene expression changes though qPCR.

RESULTS

Our analysis identified specific genes with altered expression in MUN rats at birth. Two of them, Agt and Pparg, stand out for being associated with cardiac hypertrophy and fibrosis. At the end of the lactation period, MUN males showed increased expression of Agt and decreased expression of Pparg, correlating with cardiac hypertrophy. Cross-fostering experiments revealed that lactation with control breastmilk mitigated these expression changes reducing cardiac hypertrophy in MUN males.

CONCLUSIONS

Our findings highlight the interplay between fetal programming, gene expression, and cardiac hypertrophy suggesting that lactation period is a potential intervention window to mitigate the effects of fetal programming.

IMPACT

Heart remodeling involves the alteration of several groups of genes and lactation period plays a key role in establishing gene expression modification caused by fetal programming. We could identify expression changes of relevant genes in cardiac tissue induced by undernutrition during fetal life. We expose the contribution of the lactation period in modulating the expression of Agt and Pparg, relevant genes associated with cardiac hypertrophy. This evidence reveal lactation as a crucial intervention window for preventing or countering fetal programming.

Early Life Programming of Adipose Tissue Remodeling and Browning Capacity by Micronutrients and Bioactive Compounds as a Potential Anti-Obesity Strategy

The early stages of life, especially the period from conception to two years, are crucial for shaping metabolic health and the risk of obesity in adulthood. Adipose tissue (AT) plays a crucial role in regulating energy homeostasis and metabolism, and brown AT (BAT) and the browning of white AT (WAT) are promising targets for combating weight gain. Nutritional factors during prenatal and early postnatal stages can influence the development of AT, affecting the likelihood of obesity later on. This narrative review focuses on the nutritional programming of AT features. Research conducted across various animal models with diverse interventions has provided insights into the effects of specific compounds on AT development and function, influencing the development of crucial structures and neuroendocrine circuits responsible for energy balance. The hormone leptin has been identified as an essential nutrient during lactation for healthy metabolic programming against obesity development in adults. Studies have also highlighted that maternal supplementation with polyunsaturated fatty acids (PUFAs), vitamin A, nicotinamide riboside, and polyphenols during pregnancy and lactation, as well as offspring supplementation with myo-inositol, vitamin A, nicotinamide riboside, and resveratrol during the suckling period, can impact AT features and long-term health outcomes and help understand predisposition to obesity later in life.

Recent insights into breast milk microRNA: their role as functional regulators

Breast milk (BM) is a primary biofluid that plays a crucial role in infant development and the regulation of the immune system. As a class of rich biomolecules in BM, microRNAs (miRNAs) are regarded as active factors contributing to infant growth and development. Surprisingly, these molecules exhibit resilience in harsh conditions, providing an opportunity for infants to absorb them. In addition, many studies have shown that miRNAs in breast milk, when absorbed into the gastrointestinal system, can act as a class of functional regulators to effectively regulate gene expression. Understanding the absorption pattern of BM miRNA may facilitate the creation of formula with a more optimal miRNA balance and pave the way for novel drug delivery techniques. In this review, we initially present evidence of BM miRNA absorption. Subsequently, we compile studies that integrate both in vivo and in vitro findings to illustrate the bioavailability and biodistribution of BM miRNAs post-absorption. In addition, we evaluate the strengths and weaknesses of previous studies and discuss potential variables contributing to discrepancies in their outcomes. This literature review indicates that miRNAs can be absorbed and act as regulatory agents.

Are Phe-Free Protein Substitutes Available in Italy for Infants with PKU All the Same?

Breastfeeding or standard infant formulas, alongside phenylalanine (Phe)-free protein substitutes, constitute the dietary management for infants with PKU to guarantee protein requirements are met in compliance with metabolic tolerance. This work aims to analyse the nutritional composition of Phe-free infant protein substitutes, in terms of macronutrients, micronutrients and functional components, available for PKU dietary management in Italy. A total of seven infant Phe-free protein substitutes were included in this review, six powder and one liquid. A second analysis was conducted to compare them to the composition of formulas intended for healthy infants, taking into consideration the Commission Delegated Regulation (EU) 2016/127 and Commission Delegated Regulation (EU) 2016/128 for micronutrients. The analysis revealed heterogeneity among protein substitutes suitable for infants with PKU. The energy and protein equivalents (P.Eq.) content are different; all of the substitutes contain docosahexaenoic acid (DHA) and arachidonic acid (ARA), while eicosapentaenoic acid (EPA), fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), human milk oligosaccharides (HMOs) and nucleotides are not present in all the substitutes. More attention should be paid to these infant products to ensure metabolic control of PKU, and also promote proper growth, cognitive neurodevelopment, favourable gut microbiota composition, and immune system health, while reducing the risk for non-communicable diseases (NCDs).

MicroRNA as a new bioactive component in breast milk

Breast milk is a complex and multifaceted fluid that plays a critical role in the development of infants. It is composed of water, carbohydrates, fats, proteins, vitamins, and minerals, as well as numerous bioactive compounds such as hormones, oligosaccharides, and immune proteins. Additionally, breast milk contains microRNAs, which have been found to regulate gene expression and impact various aspects of infant development. This text provides an overview of the components of human breast milk and their importance in infant development, with a focus on microRNAs. MicroRNAs are short RNA sequences that regulate gene expression posttranscriptionally, and they play an important role in shaping the mechanisms of immunity, protecting against oxidative stress, and promoting thermogenesis. The composition of breast milk can vary in the same mother between different feedings, as it changes in response to various factors such as the infant's age, feeding frequency and duration, time of day, and maternal health status. Despite the variations in breast milk composition, it still provides complete nutrition for the infant. The unique microRNA profiles in breast milk and how they are affected by various factors can have significant implications for disease prevention and treatment. Further research is needed to better understand the functions of individual microRNA molecules and their potential therapeutic applications.

Ornidazole Transfer into Colostrum and Assessment of Exposure Risk for Breastfeeding Infant: A Population Pharmacokinetic Analysis

Ornidazole is frequently used for the prevention and treatment of anaerobic infections after caesarean section. There is still a lack of data on the excretion of ornidazole in breast milk. Therefore, the aim of this study was to investigate the transfer of ornidazole into colostrum and to assess the risk of infant exposure to the drug via breast milk. Population pharmacokinetic analysis was conducted using datasets of plasma and milk concentrations obtained from 77 breastfeeding women to examine the excretion kinetics of ornidazole. Various factors that may affect the excretion of ornidazole were investigated. The final model was then used to simulate ornidazole concentration-time profiles in both plasma and milk. The drug exposure in body fluids and the potential risk for breastfeeding were assessed based on the safety threshold. Plasma ornidazole concentration data could be described well by a one-compartment model, and concentrations in breast milk were linked to this model using an estimated milk-to-plasma concentration ratio (MPRcon). Significant variables that influenced drug exposure and MPRcon were identified as total bilirubin levels (TBIL) and postnatal sampling time, respectively. Simulations showed that women with abnormal liver function (TBIL > 17 μmol/L) had higher ornidazole levels in plasma and milk than those with normal liver function (TBIL < 17 μmol/L), but the exposures through colostrum of lactating women from both groups were below the safety threshold. This work provides a simple and feasible strategy for the prediction of drug exposure in breast milk and the assessment of breastfeeding safety.

Effects of Maternal Stress on Breast Milk Production and the Microbiota of Very Premature Infants

Perinatal stress experienced by mothers of very premature newborns may influence the mother's milk and the infant's intestinal microbiota. This prospective study of mothers of very preterm infants fed with mother's own milk (MOM) was carried out in a tertiary hospital over a 2-year period. The assessment of maternal stress in 45 mothers of 52 very preterm newborns using the parental stress scale (PSS:NICU) revealed an inverse relationship between stress and MOM production in the first days of life (p = 0.012). The greatest contributor to stress was the one related to the establishment of a mother-child bond. Maternal stress was lower in mothers in whom the kangaroo method was established early (p = 0.011) and in those with a higher educational level (p = 0.032). Levels of fecal calprotectin (FC) decreased with the passage of days and were directly correlated with birthweight (p = 0.044). FC levels 7 days post-delivery were lower in newborns that received postnatal antibiotics (p = 0.027). High levels of maternal stress resulted in progressive decreases and increases in the proportions of Firmicutes and Proteobacteria species, respectively, over 15 days post-delivery, both in MOM and in fecal samples from premature newborns. These findings underscore the importance of recognizing and appropriately managing maternal stress in neonatal units, given its marked influence on both the microbiota of maternal milk and the intestinal microbiota of premature newborns.

Potential Epigenetic Effects of Human Milk on Infants' Neurodevelopment

The advantages of human milk feeding, especially in preterm babies, are well recognized. Infants' feeding with breast milk lowers the likelihood of developing a diverse range of non-communicable diseases later in life and it is also associated with improved neurodevelopmental outcomes. Although the precise mechanisms through which human milk feeding is linked with infants' neurodevelopment are still unknown, potential epigenetic effects of breast milk through its bioactive components, including non-coding RNAs, stem cells and microbiome, could at least partly explain this association. Micro- and long-non-coding RNAs, enclosed in milk exosomes, as well as breast milk stem cells, survive digestion, reach the circulation and can cross the blood-brain barrier. Certain non-coding RNAs potentially regulate genes implicated in brain development and function, whereas nestin-positive stem cells can possibly differentiate into neural cells or/and act as epigenetic regulators in the brain. Furthermore, breast milk microbiota contributes to the establishment of infant's gut microbiome, which is implicated in brain development via epigenetic modifications and key molecules' regulation. This narrative review provides an updated analysis of the relationship between breast milk feeding and infants' neurodevelopment via epigenetics, pointing out how breast milk's bioactive components could have an impact on the neurodevelopment of both full-term and preterm babies.

Stress Reduction Potential in Mice Ingesting DNA from Salmon Milt

The functionality of food-derived nucleotides is revealed when nucleotide components are ingested in emergency situations, such as during stress loading, though it is difficult to elucidate the physiological function of dietary nucleotide supplementation. Using a stress load experimental system utilizing territoriality among male mice, we evaluated whether DNA sodium salt derived from salmon milt (DNA-Na) has stress-relieving effects. It was found that stress was reduced in mice fed a diet containing a 1% concentration of DNA-Na, but this was insignificant for yeast-derived RNA. Next, we attempted to elucidate the anti-stress effects of DNA-Na using another experimental system, in which mice were subjected to chronic crowding stress associated with aging: six mice in a cage were kept until they were 7 months of age, resulting in overcrowding. We compared these older mice with 2-month-old mice that were kept in groups for only one month. The results show that the expression of genes associated with hippocampal inflammation was increased in the older mice, whereas the expression of these genes was suppressed in the DNA-Na-fed group. This suggests that dietary DNA intake may suppress inflammation in the brain caused by stress, which increases with age.

Bovine Colostrum for Veterinary and Human Health Applications: A Critical Review

Bovine colostrum harbors a diverse array of bioactive components suitable for the development of functional foods, nutraceuticals, and pharmaceuticals with veterinary and human health applications. Bovine colostrum has a strong safety profile with applications across all age groups for health promotion and the amelioration of a variety of disease states. Increased worldwide milk production and novel processing technologies have resulted in substantial growth of the market for colostrum-based products. This review provides a synopsis of the bioactive components in bovine colostrum, the processing techniques used to produce high-value colostrum-based products, and recent studies utilizing bovine colostrum for veterinary and human health.

The Human Milk Metabolome: A Scoping Literature Review

BACKGROUND

Human milk is a complex source of nutrition and other bioactives that protects infants from disease, holding a lifetime of beneficial effects. The field of metabolomics provides a robust platform through which we can better understand human milk at a level rarely examined.

RESEARCH AIM

To Identify, describe, synthesize, and critically analyze the literature within the past 5 years related to the human milk metabolome.

METHODS

We conducted a scoping literature review and quality analysis of the recent science reflecting untargeted metabolomic approaches to examining human milk. We searched six databases using the terms "breast milk," "metabolome," "metabolite," and "human milk," Out of more than 1,069 abstracts, we screened and identified 22 articles that met our inclusion criteria.

RESULTS

We extracted data related to the study author, geographic location, research design, analyses, platform used, and results. We also extracted data related to human milk research activities, including collection protocol, infant/maternal considerations, and time. Selected studies focused on a variety of phenotypes, including maternal and infant disease. Investigators used varying approaches to evaluate the metabolome, and differing milk collection protocols were observed.

CONCLUSION

The human milk metabolome is informed by many factors-which may contribute to infant health outcomes-that have resulted in disparate milk metabolomic profiles. Standardized milk collection and storage procedures should be implemented to minimize degradation. Investigators may use our findings to develop research questions that test a targeted metabolomic approach.

Human Milk-Derived Levels of let-7g-5p May Serve as a Diagnostic and Prognostic Marker of Low Milk Supply in Breastfeeding Women

Low milk supply (LMS) is associated with early breastfeeding cessation; however, the biological underpinnings in the mammary gland are not understood. MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally downregulate gene expression, and we hypothesized the profile of miRNAs secreted into milk reflects lactation performance. Longitudinal changes in milk miRNAs were measured using RNAseq in women with LMS (n = 47) and adequate milk supply (AMS; n = 123). Relationships between milk miRNAs, milk supply, breastfeeding outcomes, and infant weight gain were assessed, and interactions between milk miRNAs, maternal diet, smoking status, and BMI were determined. Women with LMS had lower milk volume (p = 0.003), were more likely to have ceased breast feeding by 24 wks (p = 0.0003) and had infants with a lower mean weight-for-length z-score (p = 0.013). Milk production was significantly associated with milk levels of miR-16-5p (R = -0.14, adj p = 0.044), miR-22-3p (R = 0.13, adj p = 0.044), and let-7g-5p (R = 0.12, adj p = 0.046). Early milk levels of let-7g-5p were significantly higher in mothers with LMS (adj p = 0.0025), displayed an interaction between lactation stage and milk supply (p < 0.001), and were negatively related to fruit intake (p = 0.015). Putative targets of let-7g-5p include genes important to hormone signaling, RNA regulation, ion transport, and the extracellular matrix, and down-regulation of two targets (PRLR and IGF2BP1/IMP1) was confirmed in mammary cells overexpressing let-7g-5p in vitro. Our data provide evidence that milk-derived miRNAs reflect lactation performance in women and warrant further investigation to assess their utility for predicting LMS risk and early breastfeeding cessation.

Breastfeeding in Phenylketonuria: Changing Modalities, Changing Perspectives

Phenylketonuria (PKU) management aims to control phenylalanine (Phe) intakes. In newborns and infants this implies possible titration of Human milk (HM) with supplementation of Phe-free formula. HM benefits, better if prolonged, are well known in healthy populations, suggesting it may be used in PKU patients. Despite that, the current literature does not define recommendations on how best perform it in such a population. The main purpose of this study was to evaluate nutrition approaches in newborns and infants affected by PKU and to define if differences can influence the duration of breastfeeding. Data from 42 PKU infants were reviewed. Of these, 67% were breastfed with the use of three different approaches. The type of approach used impacted the duration of breastfeeding, which was longer when using a pre-measured amount of Phe-free formula administered prior to HM. This is the first study to suggest a specific method for breastfeeding in PKU. Considering widely known breastfeeding benefits, both for patients and their mothers, our data should encourage adequate awareness on how to choose correct breastfeeding modalities.