Altered breast milk components in preeclampsia; An in-vitro proton NMR spectroscopy study

Preeclampsia and Its Impact on Human Milk Activin A Concentration

BACKGROUND

It is known that preeclampsia affects lactogenesis. However, data on the effects of this pathology on human milk neurobiomarker composition are not available. The aim of this study is to investigate the effects of this gestational pathology on activin A levels, a neurobiomarker known to play an important role in the development and protection of the central nervous system.

METHODS

The women recruited were divided in two different study groups: preeclamptic or normotensive women. All the human milk samples were collected using the same procedure. Activin A was quantified using an Enzyme-linked immunosorbent assay (ELISA) test. To investigate the effect of preeclampsia on the activin A concentration in the three lactation phases, a mixed linear model with a unistructural covariance structure, with the mother as the random effect, and fixed effects were performed.

RESULTS

Activin A was detected in all samples. There were no significant differences between preeclamptic and normotensive women. The only significant effect is related to the lactation phase: the difference between colostrum and mature milk (p < 0.01) was significant. In conclusion, these results allow us to affirm that breast milk's beneficial properties are maintained even if preeclampsia occurs.

Longitudinal changes in choline concentration and associated factors in human breast milk

BACKGROUND

Human breast milk is the primary source of choline and choline-containing compounds for infants at early stages of life. Choline data across lactation in Chinese human milk were limited.

OBJECTIVE

This study aimed to quantify the five choline compounds in Chinese human breast milk and explore associated factors.

METHODS

A total of 540 lactating mothers from the MUAI (Maternal Nutrition and Infant Investigation) study were included. The content of water-soluble choline (free choline, phosphocholine, glycerophosphocholine) and lipid-soluble choline (phosphatidylcholine, sphingomyelin) in 892 human milk samples collected from 0 to 400 days postpartum were examined, and associated factors were explored.

RESULTS

Choline concentrations in human milk varied from postpartum day 0-400 (92.06 ± 65.22 to 171.01 ± 47.84 mg/L). Water-soluble choline was the major component (88.6%-93.8%) in human milk and ranged from 793.03 (659.22) to 1544.43 (443.32) μmol/L. Its trajectory followed that of total choline, increasing from colostrum to transitional milk and then declining in mature milk. In contrast, lipid-soluble choline accounted for 6.2%-11.4% over lactation and had an opposite trajectory. Choline composition varied by delivery mode and parity history.

CONCLUSION

The concentrations of individual choline and choline-containing compounds during lactation in Chinese human breast milk were described for the first time. Our results address gaps in extant Chinese human milk choline data and support tailored dietary reference intakes for Chinese lactating women and infants. Our data describes the level and profile of choline from 0 to 400 days postpartum in Chinese human breast milk. This is the most updated data on choline and also the first report of water-soluble choline as the predominant type in Chinese human milk. Our results compensate for the deficiencies in data on choline in Chinese human milk.

CLINICAL TRIAL REGISTRATION

Clinical Trial Registry number: ChiCTR1800015387. Web link to study on registry: https://www.chictr.org.cn/index.aspx.

Gestational Hypertension and Human Breast Milk Composition in Correlation with the Assessment of Fetal Growth-A Pilot Study

BACKGROUND AND AIMS

1 in 10 pregnant women is diagnosed with gestational hypertension. Increasing evidence suggests that preeclampsia, gestational diabetes and gestational hypertension may affect human breast milk's lactogenesis and percentage composition. We aimed to examine whether there is any significant influence of gestational hypertension on the composition of macronutrients in human breast milk and to assess its correlation with fetal growth.

METHODS

A total of 72 breastfeeding women (34 diagnosed with gestational hypertension and 38 normotensive women during pregnancy) were recruited to the study at the Division of Neonatology, Medical University of Gdańsk, between June and December 2022. Milk samples were collected between the 3rd and 6th day of lactogenesis. Samples were analyzed using the Miris HMA™ Human Milk Analyzer (Upsala, Sweden), which evaluates the milk composition's energy, fat, carbohydrate and protein quantity. In addition, we assessed the children's anthropometric measurements (birth weight, body length and head circumference at birth). We used logistic regression to estimate the adjusted odds ratio and 95% confidence interval.

RESULTS

The mean (±standard deviation) macronutrient composition per 10 mL of milk in the GH group was 2.5 g (±0.9) of fat, 1.7 g (±0.3) of true protein, 7.7 g (±0.3) of carbohydrates and 63.2 g (±8.1) of energy, in the normotensive women group 1.0 g (±0.9) of fat, 1.7 g (±0.3) of true protein, 7.3 g (±0.4) of carbohydrates and 57.9 g (±8.6) of energy content, respectively. The fat composition was higher in the PIH group by a mean of 0.6 g (p < 0.005). Gestational hypertension had a positive, significant correlation with birth weight (p < 0.013) and the mother's pre-pregnancy weight (p < 0.005).

CONCLUSIONS

In conclusion, we found significant differences between milk composition in postpartum women with gestational hypertension compared to healthy, normotensive women. Human milk from women with gestational hypertension was found to contain a higher composition of fat, carbohydrates and energy in comparison to healthy women. Our aim is to further evaluate this correlation, as well as to assess the growth rate of newborns in order to determine the need for individualized formulas for women with pregnancy-induced hypertension, those with poor lactogenesis and those who cannot or choose not to breastfeed.

Correlation Between Maternal Age and Cytokine (IL-6 and TGF-Beta) Levels in Colostrum

BACKGROUND

Cytokines are small proteins that play an important role in cell signaling, particularly in inflammatory pathways. There are both pro- as well as anti-inflammatory cytokines that regulate this pathway and modulate the immune responses. Advancing maternal age is associated with systemic inflammation. The present study intends to evaluate the effect of advancing maternal age on cytokine (IL-6 and TGF-β) levels in colostrum, the first breast milk secreted by mothers.

METHODOLOGY

A total of 77 term deliveries were enrolled in the study. Colostrum specimens were collected and evaluated for cytokine IL-6 and TGF-β levels. Colostrum IL-6 and TGF-β levels were correlated with maternal age and were assessed using the Spearman rank correlation coefficient. Multivariate analysis was done using a linear regression model comprising age, parity, and mode of delivery.

RESULTS

Mean colostrum IL-6 and TGF-β levels were 113.3±73.1 pg/ml and 20.9±23.6 pg/ml, respectively. No significant correlation between maternal age and colostrum IL-6 levels was observed (r=0.137; p=0.314). However, there was a significant positive correlation between maternal age and colostrum TGF-β levels (r=0.452; p<0.001).

CONCLUSIONS

The findings of the study show a significant association between maternal age and colostrum TGF-β levels. The impact of colostrum cytokine levels on neonatal growth and development in context with advancing maternal age needs to be evaluated.

Infant factors that impact the ecology of human milk secretion and composition-a report from "Breastmilk Ecology: Genesis of Infant Nutrition (BEGIN)" Working Group 3

Infants drive many lactation processes and contribute to the changing composition of human milk through multiple mechanisms. This review addresses the major topics of milk removal; chemosensory ecology for the parent-infant dyad; the infant's inputs into the composition of the human milk microbiome; and the impact of disruptions in gestation on the ecology of fetal and infant phenotypes, milk composition, and lactation. Milk removal, which is essential for adequate infant intake and continued milk synthesis through multiple hormonal and autocrine/paracrine mechanisms, should be effective, efficient, and comfortable for both the lactating parent and the infant. All 3 components should be included in the evaluation of milk removal. Breastmilk "bridges" flavor experiences in utero with postweaning foods, and the flavors become familiar and preferred. Infants can detect flavor changes in human milk resulting from parental lifestyle choices, including recreational drug use, and early experiences with the sensory properties of these recreational drugs impact subsequent behavioral responses. Interactions between the infant's own developing microbiome, that of the milk, and the multiple environmental factors that are drivers-both modifiable and nonmodifiable-in the microbial ecology of human milk are explored. Disruptions in gestation, especially preterm birth and fetal growth restriction or excess, impact the milk composition and lactation processes such as the timing of secretory activation, adequacy of milk volume and milk removal, and duration of lactation. Research gaps are identified in each of these areas. To assure a sustained and robust breastfeeding ecology, these myriad infant inputs must be systematically considered.

Does Fetal Growth Adequacy Affect the Nutritional Composition of Mothers' Milk?: A Historical Cohort Study

OBJECTIVE

The study aimed to assess the association between intrauterine growth of preterm infants and energy and macronutrient contents in their mothers' milk.

STUDY DESIGN

A historical cohort of mothers of preterm infants was assessed according to offspring's intrauterine growth. Fetal growth restriction (FGR) was defined as small-for-gestational age or appropriate for gestational age with fetal growth deceleration. During the first 4 weeks after delivery, the composition of daily pool samples of mothers' milk was measured by using a mid-infrared human milk analyzer. Explanatory models for milk energy, true protein, total carbohydrate, and fat contents were obtained by generalized additive mixed effects regression models.

RESULTS

In total, 127 milk samples were analyzed from 73 mothers who delivered 92 neonates. Energy content was significantly higher in mothers with chronic hypertension (average: +6.28 kcal/dL; 95% confidence interval [CI]: 0.54-12.01; p = 0.034) and for extremely preterm compared with very preterm infants (average: +5.95 kcal/dL; 95% CI: 2.16-9.73; p = 0.003), and weakly associated with single pregnancies (average: +3.38 kcal/dL; 95% CI: 0.07-6.83; p = 0.057). True protein content was significantly higher in mothers with chronic hypertension (average: +0.91 g/dL; 95% CI: 0.63-1.19; p < 0.001) and with hypertension induced by pregnancy (average: +0.25 g/dL, 95% CI: 0.07-0.44; p = 0.007), and for extremely preterm compared with very and moderate preterm infants (average: +0.19; 95% CI: 0.01-0.38; p = 0.043 and +0.28 g/dL; 95% CI: 0.05-0.51; p = 0.017, respectively). Fat content was weakly and negatively associated with FGR, both in SGA infants and AGA infants with fetal growth deceleration (average: -0.44 g/dL; 95% CI: -0.92 to -0.05; p = 0.079 and average: -0.36 g/dL; 95% CI: -0.74 to -0.02; p = 0.066, respectively).

CONCLUSION

Energy and macronutrient contents in mothers' milk of preterm infants was significantly and positively associated with the degree of prematurity and hypertension. The hypothesis that the composition of milk is associated with FGR was not demonstrated.

KEY POINTS

· Energy and protein are higher for more immature infants.. · Energy and/or protein is higher in hypertension.. · Fat may be lower for infants with intrauterine growth restriction..

Dynamic Changes in the Human Milk Metabolome Over 25 Weeks of Lactation

Human milk (HM) provides essential nutrition for ensuring optimal infant growth and development postpartum. Metabolomics offers insight into the dynamic composition of HM. Studies have reported the impact of lactation stage, maternal genotype, and gestational age on HM metabolome. However, the majority of the studies have considered changes within the first month of lactation or sampled with large intervals. This leaves a gap in the knowledge of progressing variation in HM composition beyond the first month of lactation. The objective of this study was to investigate whether the HM metabolome from mothers with term deliveries varies beyond 1 month of lactation, during the period in which HM is considered fully mature. Human milk samples (n = 101) from 59 mothers were collected at weeks 1–2, 3–5, 7–9, and 20–25 postpartum and analyzed using ¹H nuclear magnetic resonance spectroscopy. Several metabolites varied over lactation and exhibited dynamic changes between multiple time points. Higher levels of HM oligosaccharides, cis-aconitate, O-phosphocholine, O-acetylcarnitine, gluconate, and citric acid were observed in early lactation, whereas later in lactation, levels of lactose, 3-fucosyllactose, glutamine, glutamate, and short- and medium-chain fatty acids were increased. Notably, we demonstrate that the HM metabolome is dynamic during the period of maturity.

Evaluation of Breast Milk Macronutrient Content in Preeclamptic Mothers

Background: Preeclampsia remains among the leading causes of maternal and perinatal morbidity and mortality worldwide. This study aimed to evaluate the macronutrient content of colostrum in mothers with preeclampsia. Materials and Methods: Women who delivered by cesarean section at ≤37 weeks of gestation were included in the study. Fresh colostrum samples were collected by manual expression on postpartum days 2 and 4 and were analyzed using a mid-infrared human milk analyzer. Demographic characteristics of the patients were recorded. The protein, fat, carbohydrate, and energy composition of the milk samples were compared between mothers with and without preeclampsia. Results: A total of 58 colostrum samples (25 preeclampsia, 33 nonpreeclampsia) were analyzed. The median gestational age of the infants was similar in both groups (32 versus 33 weeks; p > 0.05). There were also no differences between the groups in terms of maternal age, maternal body mass index, maternal weight gain during pregnancy, and infant gender. Median protein, fat, and carbohydrate levels in the colostrum of the preeclamptic mothers were 2.2, 2.1, and 6.3 g/dL, respectively, compared with 1.8, 2.4, and 6.2 g/dL in the nonpreeclamptic mothers, respectively. Although the colostrum of preeclamptic mothers had higher protein content and lower fat content, the difference was not statistically significant. Carbohydrate and energy contents were similar in both groups. Conclusions: The presence of preeclampsia does not cause a significant change in the macronutrient composition of mother's milk. Analyses of micronutrients at different lactation stages in larger samples are needed.

Interactions between preeclampsia and composition of the human milk: what do we know?

Purpose: Preeclampsia (PE) is a gestational hypertensive syndrome characterized by a complex disease with variable clinical manifestation. An aspect of increased interest is the possible effect of PE on the mammary gland (and therefore on breast milk composition) considering that a mother's own milk is always considered the first choice for the nutrition of all neonates. Human milk (HM) is a unique food believed to contain biological factors involved in both short and long-term benefits. This article aims to review the published papers on this topic and to offer additional insights on the role of this gestational pathology on the composition of HM.Materials and methods: This review was performed by searching the MEDLINE, EMBASE, CINHAL, and Cochrane Library databases.Results: A total of 15 articles were selected.Conclusions: Overall, the findings from the literature suggest that PE can alter the composition of HM milk. Nevertheless, the number of studies in this field are scarce, and the related protocols present some limitation, for example, evaluating the variability of just a few specific milk biochemical markers in association with this syndrome.

The Metabolomic Analysis of Human Milk Offers Unique Insights into Potential Child Health Benefits

PURPOSE OF REVIEW

Human milk is the gold standard of infant nutrition. The milk changes throughout lactation and is tailored for the infant providing the nutrients, minerals and vitamins necessary for supporting healthy infant growth. Human milk also contains low molecular weight compounds (metabolites) possibly eliciting important bioactivity. Metabolomics is the study of these metabolites. The purpose of this review was to examine recent metabolomics studies and cohort studies on human milk to assess the impact of human milk metabolomic analyses combined with investigations of infant growth and development.

RECENT FINDINGS

The metabolite profile of human milk varies among other factors according to lactation stage, gestation at birth, and maternal genes, diet and disease state. Few studies investigate how these variations impact infant growth and development. Several time-related factors affecting human milk metabolome are potentially ubiquitous among mothers, although maternal-related factors are heavily confounded, which complicates studies of metabolite abundancies and variabilities and further possibilities of observing cause and effect in infants.

A comprehensive review on non-clinical methods to study transfer of medication into breast milk - A contribution from the ConcePTION project

Breastfeeding plays a major role in the health and wellbeing of mother and infant. However, information on the safety of maternal medication during breastfeeding is lacking for most medications. This leads to discontinuation of either breastfeeding or maternal therapy, although many medications are likely to be safe. Since human lactation studies are costly and challenging, validated non-clinical methods would offer an attractive alternative. This review gives an extensive overview of the non-clinical methods (in vitro, in vivo and in silico) to study the transfer of maternal medication into the human breast milk, and subsequent neonatal systemic exposure. Several in vitro models are available, but model characterization, including quantitative medication transport data across the in vitro blood-milk barrier, remains rather limited. Furthermore, animal in vivo models have been used successfully in the past. However, these models don't always mimic human physiology due to species-specific differences. Several efforts have been made to predict medication transfer into the milk based on physicochemical characteristics. However, the role of transporter proteins and several physiological factors (e.g., variable milk lipid content) are not accounted for by these methods. Physiologically-based pharmacokinetic (PBPK) modelling offers a mechanism-oriented strategy with bio-relevance. Recently, lactation PBPK models have been reported for some medications, showing at least the feasibility and value of PBPK modelling to predict transfer of medication into the human milk. However, reliable data as input for PBPK models is often missing. The iterative development of in vitro, animal in vivo and PBPK modelling methods seems to be a promising approach. Human in vitro models will deliver essential data on the transepithelial transport of medication, whereas the combination of animal in vitro and in vivo methods will deliver information to establish accurate in vitro/in vivo extrapolation (IVIVE) algorithms and mechanistic insights. Such a non-clinical platform will be developed and thoroughly evaluated by the Innovative Medicines Initiative ConcePTION.

Maternal adiposity alters the human milk metabolome: associations between nonglucose monosaccharides and infant adiposity

BACKGROUND

Human milk composition is altered by maternal obesity. The association between milk metabolites and infant outcomes has not been thoroughly investigated.

OBJECTIVES

This study aimed to quantify maternal adiposity-related differences in the human milk metabolome and to identify metabolites associated with infant adiposity during the first 6 mo postpartum using untargeted metabolomics.

METHOD

Maternal anthropometrics were assessed ≤14 weeks of gestation. Human milk samples were collected at 0.5 mo (n = 159), 2 mo (n = 131), and 6 mo (n = 94) postpartum from normal weight (NW, BMI = 18.5-24.9 kg/m2) and obese (OB, BMI >30 kg/m2) mothers. GC-time-of-flight-MS was used to identify metabolic signatures that discriminate NW and OB women. Partial least squared (PLS)-discriminant analysis, and PLS-regression models were assessed to examine relations between metabolites and maternal BMI and fat mass. Metabolites altered by maternal obesity were used in linear mixed effect models to predict infant adiposity.

RESULTS

Multivariate modeling identified 23, 17, and 10 metabolites that described maternal adiposity indices at 0.5 mo, 2 mo, and 6 mo postpartum, respectively. Monosaccharides and sugar alcohols were the most representative annotated metabolite classes that were increased in milk from OB women and included: mannose, ribose, lyxose, lyxitol (0.5 mo); mannose, ribitol, glycerol, isothreonic acid, lyxitol (2 mo); lyxitol and isothreonic acid (6 mo). Other discriminant metabolites included: 1-monostearin, xylonolactone, shikimic acid, pseudo uridine, and dodecanol (0.5 mo); N-acetyl-D-hexosamine and fumaric acid (2 mo); uric acid and tyrosine (6 mo). Mannose, lyxitol, and shikimic acid predicted higher infant adiposity over the first 6 mo of life.

CONCLUSIONS

This study reports on 1 of the largest cohorts to date examining the metabolic profiles in human milk comparing NW and OB women. Maternal adiposity was associated with increased amounts of milk nonglucose monosaccharides. Human milk metabolomics may be useful in predicting infant adiposity. These trials were registered at www.clinicaltrials.gov as NCT01131117 and NCT02125149.

Circadian changes in the composition of human milk macronutrients depending on pregnancy duration: a cross-sectional study

Background

The purpose of this study was to evaluate the circadian variation of human milk macronutrients and energy content depending upon pregnancy duration.

Methods

One hundred eighty fresh human milk samples from 45 mothers (27 of preterm and 18 of full-term newborns) were collected on a single day chosen between the 14th to 16th day after delivery. The samples were taken four times per day at 12 PM, 6 PM, 12 AM and 6 AM. Only lactating women, who could not breastfeed their hospitalized newborns and expressed milk by breast pump, were enrolled in the study. Human milk macronutrient composition and energy count were evaluated by mid-infrared spectrophotometry.

Results

Significant differences in macronutrient content were observed between 6 AM and 12 PM for mean protein content (t = − 4.62, df = 44, p < 0.001), for mean fat content (t = − 2.10, df = 44, p = 0.04) and for mean energy content (t = − 2.24, df = 44, p = 0.03); between 6 AM and 6 PM for mean protein content (t = − 2.41, df = 43, p = 0.02), for mean fat content (t = − 3.76, df = 43, p = 0.001) and for mean energy content (t = − 3.85, df = 43, p < 0.001); between 12 PM and 12 AM for mean protein content (Wilcoxon test V = 75.5, p = 0.001), for mean fat content (t = 2.50, df = 44, p = 0.02) and for mean energy content (t = 2.74, df = 44, p = 0.01); between 6 PM and 12 AM for mean protein content (V = 229, p = 0.02), for mean fat content (t = 4.39, df = 43, p < 0.001) and for mean energy content (t = − 4.57, df = 43, p < 0.001). The average content of carbohydrates did not change significantly during the 24 h. The samples of preterm newborns’ mothers had more apparent diurnal fluctuations in macronutrient content.

Conclusions

Our study revealed significant diurnal variations in protein and fat in human milk, and these circadian fluctuations were more apparent in the milk of mothers of preterm infants.

The Determinants of the Human Milk Metabolome and Its Role in Infant Health

Human milk is needed for optimal growth as it satisfies both the nutritional and biological needs of an infant. The established relationship between breastfeeding and an infant’s health is attributable to the nutritional and non-nutritional, functional components of human milk including metabolites such as the lipids, amino acids, biogenic amines and carbohydrates. These components have diverse roles, including protecting the infant against infections and guiding the development of the infant’s immature immune system. In this review, we provide an in-depth and updated insight into the immune modulatory and anti-infective role of human milk metabolites and their effects on infant health and development. We also review the literature on potential determinants of the human milk metabolome, including maternal infectious diseases such as human immunodeficiency virus and mastitis.

Current Practice in Untargeted Human Milk Metabolomics

Human milk (HM) is considered the gold standard for infant nutrition. HM contains macro- and micronutrients, as well as a range of bioactive compounds (hormones, growth factors, cell debris, etc.). The analysis of the complex and dynamic composition of HM has been a permanent challenge for researchers. The use of novel, cutting-edge techniques involving different metabolomics platforms has permitted to expand knowledge on the variable composition of HM. This review aims to present the state-of-the-art in untargeted metabolomic studies of HM, with emphasis on sampling, extraction and analysis steps. Workflows available from the literature have been critically revised and compared, including a comprehensive assessment of the achievable metabolome coverage. Based on the scientific evidence available, recommendations for future untargeted HM metabolomics studies are included.

Cross talk of vascular endothelial growth factor and neurotrophins in mammary gland development

During the period of lactation, there is extensive growth and development of the mammary gland in order to fulfil the increased demands of milk for the growing infant. Angiogenesis plays a key role in alveolar development and facilitates optimal milk production. Vascular endothelial growth factor (VEGF) is one of the key growth factors regulating angiogenesis in mammary gland. Apart from VEGF, neurotrophins are also known to regulate angiogenesis through direct or indirect mechanisms. Few studies have demonstrated mRNA levels of neurotrophins and their receptors in mammary gland both in humans and rodents. A cross talk between VEGF and neurotrophins has been described in placental development. The enteric and central nervous system are not fully developed at birth, making it imperative to have appropriate levels of angiogenic factors and neurotrophins during postnatal period. The current review summarises studies which describe the role of neurotrophins and angiogenic factors in the mammary gland development.

Maternal obesity and the human milk metabolome: associations with infant body composition and postnatal weight gain

BACKGROUND

Maternal obesity is a risk factor for childhood obesity; this is a major public health concern given that ∼40% of pregnant women are either overweight or obese. Whether differences in milk composition in lean compared with obese women contribute to childhood obesity is unclear.

OBJECTIVES

We aimed to analyze relationships between maternal obesity and human milk metabolites, infant body composition, and postnatal weight gain.

METHODS

This was a prospective study in which mothers intending to breastfeed exclusively, and their newborn infants, were enrolled at delivery (n = 35 mother-infant pairs). We excluded mothers with diabetes, other medical conditions, or pregnancy complications. Participants were grouped by maternal prepregnancy BMI <25 (lean) or ≥25 kg/m2 (overweight/obese). We analyzed infant body composition by dual-energy X-ray absorptiometry and used untargeted liquid chromatography-gas chromatography-mass spectrometry to measure the milk content of 275 metabolites at 1 and 6 mo postpartum.

RESULTS

At 1 mo postpartum, 10 metabolites differed between overweight/obese and lean groups with nominal P < 0.05, but none was altered with a false discovery rate <0.25. Many differentially abundant metabolites belonged to the same chemical class; e.g., 4/10 metabolites were nucleotide derivatives, and 3/10 were human milk oligosaccharides. Milk adenine correlated positively with both continuously distributed maternal BMI and with infant adiposity and fat accrual. Analysis of milk composition at 6 mo postpartum revealed 20 differentially abundant metabolites (P < 0.05) in overweight/obese compared with lean women, including 6 metabolites with a false discovery rate of <0.25. At both 1 and 6 mo, human milk abundance of 1,5-anhydroglucitol, which has not previously been described in milk, was positively associated with maternal BMI.

CONCLUSIONS

Maternal obesity is associated with changes in the human milk metabolome. While only a subset of metabolites correlated with both maternal and infant weight, these point to potential milk-dependent mechanisms for mother-child transmission of obesity. This trial was registered at www.clinicaltrials.gov as NCT02535637.

Worldwide Variation in Human Milk Metabolome: Indicators of Breast Physiology and Maternal Lifestyle?

Human milk provides essential substrates for the optimal growth and development of a breastfed infant. Besides providing nutrients to the infant, human milk also contains metabolites which form an intricate system between maternal lifestyle, such as the mother's diet and the gut microbiome, and infant outcomes. This study investigates the variation of these human milk metabolites from five different countries. Human milk samples (n = 109) were collected one month postpartum from Australia, Japan, the USA, Norway, and South Africa and were analyzed by nuclear magnetic resonance. The partial least squares discriminant analysis (PLS-DA) showed separation between either maternal countries of origin or ethnicities. Variation between countries in concentration of metabolites, such as 2-oxoglutarate, creatine, and glutamine, in human milk, between countries, could provide insights into problems, such as mastitis and/or impaired functions of the mammary glands. Several important markers of milk production, such as lactose, betaine, creatine, glutamate, and glutamine, showed good correlation between each metabolite. This work highlights the importance of milk metabolites with respect to maternal lifestyle and the environment, and also provides the framework for future breastfeeding and microbiome studies in a global context.

Normal Human Lactation: closing the gap

With the exception of infant growth, there are no well-defined parameters describing normal human lactation. This represents a major gap in the continuum of care that does not exist for other major organs. Biological normality occurs naturally and is characterized by well-integrated function. We have proposed a definition that highlights four key elements that describe parameters for biological normality: comfort, milk supply, infant health, and maternal health. Notwithstanding the current limitations, published data have been collated to provide preliminary markers for the initiation of lactation and to describe objective tests once lactation is established. Reference limits have been calculated for maternal markers of secretory activation, including progesterone in maternal blood and total protein, lactose, sodium, and citrate in maternal milk. Objective measurements for established lactation, including 3-hourly pumping and 24-hour milk production, together with pre-feed to post-feed milk fat changes (a useful indicator of the available milk removed by the infant) have been outlined. Considered together with the parameters describing normal function, this information provides a preliminary objective framework for the assessment of human lactation.

Applications of Metabolomics in the Study and Management of Preeclampsia; A Review of the Literature

Introduction

Preeclampsia represents a major public health burden worldwide, but predictive and diagnostic biomarkers are lacking. Metabolomics is emerging as a valuable approach to generating novel biomarkers whilst increasing the mechanistic understanding of this complex condition.

Objectives

To summarize the published literature on the use of metabolomics as a tool to study preeclampsia.

Methods

PubMed and Web of Science were searched for articles that performed metabolomic profiling of human biosamples using either Mass-spectrometry or Nuclear Magnetic Resonance based approaches and which included preeclampsia as a primary endpoint.

Results

Twenty-eight studies investigating the metabolome of preeclampsia in a variety of biospecimens were identified. Individual metabolite and metabolite profiles were reported to have discriminatory ability to distinguish preeclamptic from normal pregnancies, both prior to and post diagnosis. Lipids and carnitines were among the most commonly reported metabolites. Further work and validation studies are required to demonstrate the utility of such metabolites as preeclampsia biomarkers.

Conclusion

Metabolomic-based biomarkers of preeclampsia have yet to be integrated into routine clinical practice. However, metabolomic profiling is becoming increasingly popular in the study of preeclampsia and is likely to be a valuable tool to better understand the pathophysiology of this disorder and to better classify its subtypes, particularly when integrated with other omic data.