Female and male human babies have distinct blood metabolomic patterns

Parenteral Nutrition in the Pediatric Oncologic Population: Are There Any Sex Differences?

Gender-based medicine is attracting increasing interest every day, but studies on pediatric populations are still limited. In this setting, sex differences among patients undergoing total parenteral nutrition (TPN) have not been previously reported. This study investigated the presence of sex differences in parenteral nutrition composition and outcomes among a cohort of pediatric patients admitted at the Oncohematology and Bone Marrow Transplant Unit of the Institute for Maternal and Child Health "Burlo Garofolo" of Trieste, Italy. For all 145 recruited patients (87 males, 58 females), the following data were collected: age, sex, volume and duration of TPN, macro- and micronutrient composition of TPN bags, electrolytic or blood gases imbalance, glycolipid alterations, liver damage during TPN, and the incidence of sepsis and thrombosis. The analysis showed that females required higher daily phosphate intake (p = 0.054) and essential amino acid supplementation (p = 0.07), while males had a higher incidence of hypertriglyceridemia (p < 0.05) and cholestasis. A higher incidence of sepsis was found in the non-transplanted male population (p < 0.05). No significant differences were appreciable in other analyzed variables. This study aims to create a basis for future gender-based nutritional recommendations in the pediatric field.

Sexually dimorphic methylation patterns characterize the placenta and blood from extremely preterm newborns

BACKGROUND

Health outcomes among children born prematurely are known to be sexually dimorphic, with male infants often more affected, yet the mechanism behind this observation is not clear. CpG methylation levels in the placenta and blood also differ by sex and are associated with adverse health outcomes. We contrasted CpG methylation levels in the placenta and neonatal blood (n = 358) from the Extremely Low Gestational Age Newborn (ELGAN) cohort based on the EPIC array, which assays over 850,000 CpG sites across the epigenome. Sex-specific epigenome-wide association analyses were conducted for the placenta and neonatal blood samples independently, and the results were compared to determine tissue-specific differences between the methylation patterns in males and females. All models were adjusted for cell type heterogeneity. Enrichment pathway analysis was performed to identify the biological functions of genes related to the sexually dimorphic CpG sites.

RESULTS

Approximately 11,500 CpG sites were differentially methylated in relation to sex. Of these, 5949 were placenta-specific and 5361 were blood-specific, with only 233 CpG sites overlapping in both tissues. For placenta-specific CpG sites, 90% were hypermethylated in males. For blood-specific CpG sites, 95% were hypermethylated in females. In the placenta, keratinocyte differentiation biological pathways were enriched among the differentially methylated genes. No enrichment pathways were observed for blood.

CONCLUSIONS

Distinct methylation patterns were observed between male and female children born extremely premature, and keratinocyte differentiation pathways were enriched in the placenta. These findings provide new insights into the epigenetic mechanisms underlying sexually dimorphic health outcomes among extremely premature infants.

Contribution of Genetic Test to Early Diagnosis of Methylenetetrahydrofolate Reductase (MTHFR) Deficiency: The Experience of a Reference Center in Southern Italy

BACKGROUND

the deficiency of 5,10-Methylenetetrahydrofolate reductase (MTHFR) constitutes a rare and severe metabolic disease and is included in most expanded newborn screening (NBS) programs worldwide. Patients with severe MTHFR deficiency develop neurological disorders and premature vascular disease. Timely diagnosis through NBS allows early treatment, resulting in improved outcomes.

METHODS

we report the diagnostic yield of genetic testing for MTHFR deficiency diagnosis, in a reference Centre of Southern Italy between 2017 and 2022. MTHFR deficiency was suspected in four newborns showing hypomethioninemia and hyperhomocysteinemia; otherwise, one patient born in pre-screening era showed clinical symptoms and laboratory signs that prompted to perform genetic testing for MTHFR deficiency.

RESULTS

molecular analysis of the MTHFR gene revealed a genotype compatible with MTHFR deficiency in two NBS-positive newborns and in the symptomatic patient. This allowed for promptly beginning the adequate metabolic therapy.

CONCLUSIONS

our results strongly support the need for genetic testing to quickly support the definitive diagnosis of MTHFR deficiency and start therapy. Furthermore, our study extends knowledge of the molecular epidemiology of MTHFR deficiency by identifying a novel mutation in the MTHFR gene.

Sex-Gender-Based Differences in Metabolic Diseases

Sexual dimorphism creates different biological and cellular activities and selective regulation mechanisms in males and females, thus generating differential responses in health and disease. In this scenario, the sex itself is a source of physiologic metabolic disparities that depend on constitutive genetic and epigenetic features that characterize in a specific manner one sex or the other. This has as a direct consequence a huge impact on the metabolic routes that drive the phenotype of an individual. The impact of sex is being clearly recognized also in disease, whereas male and females are more prone to the development of some disorders, or have selective responses to drugs and therapeutic treatments. Actually, very less is known regarding the probable differences guided by sex in the context of inherited metabolic disorders, owing to the scarce consideration of sex in such restricted field, accompanied by an intrinsic bias connected with the rarity of such diseases. Metabolomics technologies have been ultimately developed and adopted for being excellent tools for the investigation of metabolic mechanisms, for marker discovery or monitoring, and for supporting diagnostic procedures of metabolic disorders. Hence, metabolomic approaches can excellently embrace the discovery of sex differences, especially when associated to the outcome or the management of certain inborn errors of the metabolism.

Metabolic impact of infant formulas in young infants. An outlook from the urine metabolome

Introduction

Although breast milk is the ideal food source for newborns during the first six months of life, a high percentage of children receive infant formulas. There is evidence that specific diet habits may influence individual metabolic profile. Therefore, in newborns, such profile can be influenced by the use of infantile formulas given the composition differences that display compared to human milk. Up to now, there are no reports in the literature that address this issue.

Objectives

this work aims to compare the metabolic profile of full-term newborns that were feed with either breast milk (n = 32) or infantile formulas (n = 21). Methods: Metabolic profile was established based on urine analysis through gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (H-NMR).

Results

our results evidenced a more gluconeogenic profile in breast-fed infants characterized by elevation of Kreb's cycle intermediaries like fumaric, succinic and ketoglutaric acids compared to infants receiving infant formula. In addition, infant formula fed infants presented urinary excretion of metabolites derived from specific compounds present in this type of diet that were not observed in breast-fed infants, for instance D-glucitol, and 4-deoxytetronic. Moreover, in infant formula fed infants there was excretion of basal levels of metabolites of clinical relevance like 3-hydroxy-3-methyl-glutaric, 2-methyl-3-keto-valeric and 3,4-dihydroxybutyric.

Conclusion

These results show the importance of understanding the metabolic impact of diet in newborn population in normal and pathological contexts.

The newborn metabolome: associations with gestational diabetes, sex, gestation, birth mode, and birth weight

BACKGROUND

Pathways towards many adult-onset conditions begin early in life, even in utero. Maternal health in pregnancy influences this process, but little is known how it affects neonatal metabolism. We investigated associations between pregnancy and birth factors and cord blood metabolomic profile in a large, population-derived cohort.

METHODS

Metabolites were measured using nuclear magnetic resonance in maternal (28 weeks gestation) and cord serum from 912 mother-child pairs in the Barwon Infant Study pre-birth cohort. Associations between maternal (metabolites, age, BMI, smoking), pregnancy (pre-eclampsia, gestational diabetes (GDM)), and birth characteristics (delivery mode, gestational age, weight, infant sex) with 72 cord blood metabolites were examined by linear regression.

RESULTS

Delivery mode, sex, gestational age, and birth weight were associated with specific metabolite levels in cord blood, including amino acids, fatty acids, and cholesterols. GDM was associated with higher cord blood levels of acetoacetate and 3-hydroxybutyrate.

CONCLUSIONS

Neonatal factors, particularly delivery mode, were associated with many cord blood metabolite differences, including those implicated in later risk of cardiometabolic disease. Associations between GDM and higher offspring ketone levels at birth are consistent with maternal ketosis in diabetic pregnancies. Further work is needed to determine whether these neonatal metabolome differences associate with later health outcomes.

IMPACT

Variations in blood metabolomic profile have been linked to health status in adults and children, but corresponding data in neonates are scarce. We report evidence that pregnancy complications, mode of delivery, and offspring characteristics, including sex, are independently associated with a range of circulating metabolites at birth, including ketone bodies, amino acids, cholesterols, and inflammatory markers. Independent of birth weight, exposure to gestational diabetes is associated with higher cord blood ketone bodies and citrate. These findings suggest that pregnancy complications, mode of delivery, gestational age, and measures of growth influence metabolic pathways prior to birth, potentially impacting later health and development.

Challenges in Metabolomics-Based Tests, Biomarkers Revealed by Metabolomic Analysis, and the Promise of the Application of Metabolomics in Precision Medicine

Metabolomics helps identify metabolites to characterize/refine perturbations of biological pathways in living organisms. Pre-analytical, analytical, and post-analytical limitations that have hampered a wide implementation of metabolomics have been addressed. Several potential biomarkers originating from current targeted metabolomics-based approaches have been discovered. Precision medicine argues for algorithms to classify individuals based on susceptibility to disease, and/or by response to specific treatments. It also argues for a prevention-based health system. Because of its ability to explore gene-environment interactions, metabolomics is expected to be critical to personalize diagnosis and treatment. Stringent guidelines have been applied from the very beginning to design studies to acquire the information currently employed in precision medicine and precision prevention approaches. Large, prospective, expensive and time-consuming studies are now mandatory to validate old, and discover new, metabolomics-based biomarkers with high chances of translation into precision medicine. Metabolites from studies on saliva, sweat, breath, semen, feces, amniotic, cerebrospinal, and broncho-alveolar fluid are predicted to be needed to refine information from plasma and serum metabolome. In addition, a multi-omics data analysis system is predicted to be needed for omics-based precision medicine approaches. Omics-based approaches for the progress of precision medicine and prevention are expected to raise ethical issues.

Differences between Arterial and Venous Umbilical Cord Plasma Metabolome and Association with Parity

Umbilical cord blood is frequently used in health monitoring of the neonate. Results may be affected by the proportion of arterial and venous cord blood, the venous blood coming from the mother to supply oxygen and nutrients to the infant, and the arterial carrying waste products from the fetus. Here, we sampled arterial and venous umbilical cords separately from 48 newly delivered infants and examined plasma metabolomes using GC-MS/MS metabolomics. We investigated differences in metabolomes between arterial and venous blood and their associations with gestational length, birth weight, sex, and whether the baby was the first born or not, as well as maternal age and BMI. Using multilevel random forest analysis, a classification rate of 79% was achieved for arteriovenous differences (p = 0.004). Several monosaccharides had higher concentrations in the arterial cord plasma while amino acids were higher in venous plasma, suggesting that the main differences in the measured arterial and venous plasma metabolomes are related to amino acid and energy metabolism. Venous cord plasma metabolites related to energy metabolism were positively associated with parity (77% classification rate, p = 0.004) while arterial cord plasma metabolites were not. This underlines the importance of defining cord blood type for metabolomic studies.

Asparagine Metabolism in Tumors Is Linked to Poor Survival in Females with Colorectal Cancer: A Cohort Study

The interplay between the sex-specific differences in tumor metabolome and colorectal cancer (CRC) prognosis has never been studied and represents an opportunity to improve patient outcomes. This study examines the link between tumor metabolome and prognosis by sex for CRC patients. Using untargeted metabolomics analysis, abundances of 91 metabolites were obtained from primary tumor tissues from 197 patients (N = 95 females, N = 102 males) after surgical colectomy for stage I-III CRC. Cox Proportional hazard (PH) regression models estimated the associations between tumor metabolome and 5-year overall survival (OS) and recurrence-free survival (RFS), and their interactions with sex. Eleven metabolites had significant sex differences in their associations with 5-year OS, and five metabolites for 5-year RFS. The metabolites asparagine and serine had sex interactions for both OS and RFS. Furthermore, in the asparagine synthetase (ASNS)-catalyzed asparagine synthesis pathway, asparagine was associated with substantially poorer OS (HR (95% CI): 6.39 (1.78–22.91)) and RFS (HR (95% CI): 4.36 (1.39–13.68)) for female patients only. Similar prognostic disadvantages in females were seen in lysophospholipid and polyamine synthesis. Unique metabolite profiles indicated that increased asparagine synthesis was associated with poorer prognosis for females only, providing insight into precision medicine for CRC treatment stratified by sex.

Defining the Healthy Infant Metabolome: Liquid Chromatography Tandem-Mass Spectrometry Analysis of Dried Blood Spot Extracts from the Prospective Research on Early Determinants of Illness and Children's Health Trajectories Birth Cohort Study

Newborn screening using dried plasma spots offers preanalytical advantages over conventional cards for plasma-associated targets of interest. Herein we present dried plasma spot-based methods for measuring metabolites using a 250+ compound liquid chromatography tandem mass spectrometry library. Quality assurance reduced this library to 134, and from these, 30 compounds determined the normal newborn reference ranges.

Relationship between amniotic fluid metabolic profile with fetal gender, maternal age, and gestational week

BACKGROUND

Amniotic fluid (AF) provides vital information on fetal development, which is also valuable in identifying fetal abnormalities during pregnancy. However, the relationship between the metabolic profile of AF in the second trimester of a normal pregnancy with several maternal-fetal parameters remains poorly understood, which therefore limits its application in clinical practice. The aim of this study was to explore the association between the metabolic profile of AF with fetal gender, maternal age, and gestational week using an untargeted metabolomics method.

METHODS

A total of 114 AF samples were analyzed in this study. Clinical data on fetal gender, maternal age, and gestational week of these samples were collected. Samples were analyzed by gas chromatography/time-of-flight-mass spectrometry (GC-TOF/MS). Principal component analysis(PCA), orthogonal partial least square discrimination analysis(OPLS-DA) or partial least square discrimination analysis (PLS-DA) were conducted to compare metabolic profiles, and differential metabolites were obtained by univariate analysis.

RESULTS

Both PCA and OPLS-DA demonstrated no significant separation trend between the metabolic profiles of male and female fetuses, and there were only 7 differential metabolites. When the association between the maternal age on AF metabolic profile was explored, both PCA and PLS-DA revealed that the maternal age in the range of 21 to 40 years had no significant effect on the metabolic profile of AF, and only four different metabolites were found. There was no significant difference in the metabolic profiles of AF from fetuses of 17-22 weeks, and 23 differential metabolites were found.

CONCLUSIONS

In the scope of our study, there was no significant correlation between the AF metabolic profile and the fetal gender, maternal age and gestational week of a small range. Nevertheless, few metabolites appeared differentially expressed.

Associations of maternal bisphenol urine concentrations during pregnancy with neonatal metabolomic profiles

BACKGROUND

Fetal exposure to bisphenols is associated with altered fetal growth, adverse birth outcomes and childhood cardio-metabolic risk factors. Metabolomics may serve as a tool to identify the mechanisms underlying these associations. We examined the associations of maternal bisphenol urinary concentrations in pregnancy with neonatal metabolite profiles from cord blood.

METHODS

In a population-based prospective cohort study among 225 mother-child pairs, maternal urinary bisphenol A, S and F concentrations in first, second and third trimester were measured. LC-MS/MS was used to determine neonatal concentrations of amino acids, non-esterified fatty acids (NEFA), phospholipids (PL), and carnitines in cord blood.

RESULTS

No associations of maternal total bisphenol concentrations with neonatal metabolite profiles were present. Higher maternal average BPA concentrations were associated with higher neonatal mono-unsaturated alkyl-lysophosphatidylcholine concentrations, whereas higher maternal average BPS was associated with lower neonatal overall and saturated alkyl-lysophosphatidylcholine (p-values < 0.05).Trimester-specific analyses showed that higher maternal BPA, BPS and BPF were associated with alterations in neonatal NEFA, diacyl-phosphatidylcholines, acyl-alkyl-phosphatidylcholines, alkyl-lysophosphatidylcholine, sphingomyelines and acyl-carnitines, with the strongest effects for third trimester maternal bisphenol and neonatal diacyl-phosphatidylcholine, sphingomyeline and acyl-carnitine metabolites (p-values < 0.05). Associations were not explained by maternal socio-demographic and lifestyle characteristics or birth characteristics.

DISCUSSION

Higher maternal bisphenol A, F and S concentrations in pregnancy are associated with alterations in neonatal metabolite profile, mainly in NEFA, PL and carnitines concentrations. These findings provide novel insight into potential mechanisms underlying associations of maternal bisphenol exposure during pregnancy with adverse offspring outcomes but need to be replicated among larger, diverse populations.

Metabolic biomarkers of small and large for gestational age newborns

BACKGROUND

Small for gestational age (SGA) and large for gestational age (LGA) newborns are at increased risk for developmental, metabolic and cardiovascular morbidities.

AIMS

To compare the metabolic biomarkers of SGA and LGA infants with those of appropriate for gestational age (AGA) newborns in order to shed more light on a possible pathogenesis of those morbidities.

STUDY DESIGN

An observational retrospective study.

SUBJECTS

70,809 term newborns divided into AGA, SGA, LGA, and severe subcategories (<3rd percentile or ≥97th percentile).

OUTCOME MEASURES

18 metabolites were measured by dried blood tandem mass spectrometry and compared in between groups in univariate and multivariate logistic regression.

RESULTS

SGA newborns had a significant likelihood for elevated methionine, proline, free carnitine, and reduced valine levels compared to AGA newborns (P < .0001). Severe SGA showed more apparent trends including elevated leucine. LGA newborns had a significant likelihood for low citrulline, glutamine, proline, tyrosine, and elevated leucine levels (P ≤ .0033). Severe LGA newborns showed the same trends, with the exception of citrulline and glutamine.

CONCLUSIONS

SGA and LGA newborns demonstrate distinct metabolic biomarkers in newborn screening. Most of the altered metabolites in the SGA group were elevated while those in the LGA group were decreased in comparison to AGA newborns. These trends were more apparent in the severe SGA subgroup while they mostly remained the same in the severe LGA subgroup. Whether these metabolic changes are involved with or can predict long-term outcome awaits further trials.

The Metallome as a Link Between the "Omes" in Autism Spectrum Disorders

Metal dyshomeostasis plays a significant role in various neurological diseases such as Alzheimer's disease, Parkinson's disease, Autism Spectrum Disorders (ASD), and many more. Like studies investigating the proteome, transcriptome, epigenome, microbiome, etc., for years, metallomics studies have focused on data from their domain, i.e., trace metal composition, only. Still, few have considered the links between other "omes," which may together result in an individual's specific pathologies. In particular, ASD have been reported to have multitudes of possible causal effects. Metallomics data focusing on metal deficiencies and dyshomeostasis can be linked to functions of metalloenzymes, metal transporters, and transcription factors, thus affecting the proteome and transcriptome. Furthermore, recent studies in ASD have emphasized the gut-brain axis, with alterations in the microbiome being linked to changes in the metabolome and inflammatory processes. However, the microbiome and other "omes" are heavily influenced by the metallome. Thus, here, we will summarize the known implications of a changed metallome for other "omes" in the body in the context of "omics" studies in ASD. We will highlight possible connections and propose a model that may explain the so far independently reported pathologies in ASD.

Studying Autism Using Untargeted Metabolomics in Newborn Screening Samples

Main risk factors of autism spectrum disorder (ASD) include both genetic and non-genetic factors, especially prenatal and perinatal events. Newborn screening dried blood spot (DBS) samples have great potential for the study of early biochemical markers of disease. To study DBS strengths and limitations in the context of ASD research, we analyzed the metabolomic profiles of newborns later diagnosed with ASD. We performed LC-MS/MS-based untargeted metabolomics on DBS from 37 case-control pairs randomly selected from the iPSYCH sample. After preprocessing using MZmine 2.41, metabolites were putatively annotated using mzCloud, GNPS feature-based molecular networking, and MolNetEnhancer. A total of 4360 mass spectral features were detected, of which 150 (113 unique) could be putatively annotated at a high confidence level. Chemical structure information at a broad level could be retrieved for 1009 metabolites, covering 31 chemical classes. Although no clear distinction between cases and controls was revealed, our method covered many metabolites previously associated with ASD, suggesting that biochemical markers of ASD are present at birth and may be monitored during newborn screening. Additionally, we observed that gestational age, age at sampling, and month of birth influence the metabolomic profiles of newborn DBS, which informs us on the important confounders to address in future studies.

Sex Affects Human Premature Neonates' Blood Metabolome According to Gestational Age, Parenteral Nutrition, and Caffeine Treatment

Prematurity is the leading cause of neonatal deaths and high economic costs; it depends on numerous biological and social factors, and is highly prevalent in males. Several factors can affect the metabolome of premature infants. Accordingly, the aim of the present study was to analyze the role played by gestational age (GA), parenteral nutrition (PN), and caffeine treatment in sex-related differences of blood metabolome of premature neonates through a MS/MS-based targeted metabolomic approach for the detection of amino acids and acylcarnitines in dried blood spots. GA affected the blood metabolome of premature neonates: male and female very premature infants (VPI) diverged in amino acids but not in acylcarnitines, whereas the opposite was observed in moderate or late preterm infants (MLPI). Moreover, an important reduction of metabolites was observed in female VPI fed with PN, suggesting that PN might not satisfy an infant's nutritional needs. Caffeine showed the highest significant impact on metabolite levels of male MLPI. This study proves the presence of a sex-dependent metabolome in premature infants, which is affected by GA and pharmacological treatment (e.g., caffeine). Furthermore, it describes an integrated relationship among several features of physiology and health.

Dysregulation of lipid metabolism and pathological inflammation in patients with COVID-19

In recent months, Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the world. COVID-19 patients show mild, moderate or severe symptoms with the latter ones requiring access to specialized intensive care. SARS-CoV-2 infections, pathogenesis and progression have not been clearly elucidated yet, thus forcing the development of many complementary approaches to identify candidate cellular pathways involved in disease progression. Host lipids play a critical role in the virus life, being the double-membrane vesicles a key factor in coronavirus replication. Moreover, lipid biogenesis pathways affect receptor-mediated virus entry at the endosomal cell surface and modulate virus propagation. In this study, targeted lipidomic analysis coupled with proinflammatory cytokines and alarmins measurement were carried out in serum of COVID-19 patients characterized by different severity degree. Serum IL-26, a cytokine involved in IL-17 pathway, TSLP and adiponectin were measured and correlated to lipid COVID-19 patient profiles. These results could be important for the classification of the COVID-19 disease and the identification of therapeutic targets.

Umbilical cord blood metabolome differs in relation to delivery mode, birth order and sex, maternal diet and possibly future allergy development in rural children

Allergy is one of the most common diseases among young children yet all factors that affect development of allergy remain unclear. In a small cohort of 65 children living in the same rural area of south-west Sweden, we have previously found that maternal factors, including prenatal diet, affect childhood allergy risk, suggesting that in utero conditions may be important for allergy development. Here, we studied if metabolites in the umbilical cord blood of newborns may be related to development of childhood allergy, accounting for key perinatal factors such as mode of delivery, birth order and sex. Available umbilical cord blood plasma samples from 44 of the participants were analysed using gas chromatography-mass spectrometry metabolomics; allergy was diagnosed by specialised paediatricians at ages 18 months, 3 years and 8 years and included eczema, asthma, food allergy and allergic rhinoconjunctivitis. Nineteen cord blood metabolites were related to future allergy diagnosis though there was no clear pattern of up- or downregulation of metabolic pathways. In contrast, perinatal factors birth order, sex and mode of delivery affected several energy and biosynthetic pathways, including glutamate and aspartic acid—histidine metabolism (p = 0.004) and the tricarboxylic acid cycle (p = 0.006) for birth order; branched chain amino acid metabolism (p = 0.0009) and vitamin B₆ metabolism (p = 0.01) for sex; and glyoxylate and dicarboxylic acid metabolism (p = 0.005) for mode of delivery. Maternal diet was also related to some of the metabolites associated with allergy. In conclusion, the cord blood metabolome includes individual metabolites that reflect lifestyle, microbial and other factors that may be associated with future allergy diagnosis, and also reflects temporally close events/factors. Larger studies are required to confirm these associations, and perinatal factors such as birth order or siblings must be considered in future cord-blood metabolome studies.

Human Umbilical Cord: Information Mine in Sex-Specific Medicine

Biological differences between sexes should be considered in all stages of research, as sexual dimorphism starts in utero leading to sex-specific fetal programming. In numerous biomedical fields, there is still a lack of stratification by sex despite primary cultured cells retaining memory of the sex and of the donor. The sex of donors in biological research must be known because variations in cells and cellular components can be used as endpoints, biomarkers and/or targets of pharmacological studies. This selective review focuses on the current findings regarding sex differences observed in the umbilical cord, a widely used source of research samples, both in the blood and in the circulating cells, as well as in the different cellular models obtainable from it. Moreover, an overview on sex differences in fetal programming is reported. As it emerges that the sex variable is still often forgotten in experimental models, we suggest that it should be mandatory to adopt sex-oriented research, because only awareness of these issues can lead to innovative research.

Sex differences in infant blood metabolite profile in association with weight and adiposity measures

BACKGROUND

Nuclear magnetic resonance (NMR) metabolic profiling quantifies a large number of metabolites. From adolescence, specific metabolites are influenced by age, sex and body mass index; data on early-life metabolic profiles are limited. We investigated associations between sex, birth weight, weight and adiposity with NMR metabolic profile at age 12 months.

METHODS

The plasma NMR metabolic profile was quantified in infants (n = 485) from the Barwon Infant Study. Associations between 74 metabolites and sex, birth weight z-score and 12-month measures (weight z-score, skinfold thickness, weight-for-length z-score) were examined using linear regression models.

RESULTS

Several cholesterol and fatty acid measures were higher (0.2-0.3 SD) in girls than in boys; we observed modest sex-specific associations of birth weight z-scores and 12-month sum of skinfold thicknesses with metabolites. The pattern of associations between weight z-score and weight-for-length z-score with metabolites at 12 months was more pronounced in girls, particularly for fatty acid ratios.

CONCLUSIONS

We identified sex differences in the infant metabolic profile. Sex-specific patterns observed differ from those reported in older children and adults. We also identified modest cross-sectional associations between anthropometric and adiposity measures and metabolites, some of which were sex specific.

ZSCAN4+ mouse embryonic stem cells have an oxidative and flexible metabolic profile

Cultured mouse embryonic stem cells are a heterogeneous population with diverse differentiation potential. In particular, the subpopulation marked by Zscan4 expression has high stem cell potency and shares with 2 cell stage preimplantation embryos both genetic and epigenetic mechanisms that orchestrate zygotic genome activation. Although embryonic de novo genome activation is known to rely on metabolites, a more extensive metabolic characterization is missing. Here we analyze the Zscan4⁺ mouse stem cell metabolic phenotype associated with pluripotency maintenance and cell reprogramming. We show that Zscan4⁺ cells have an oxidative and adaptable metabolism, which, on one hand, fuels a high bioenergetic demand and, on the other hand, provides intermediate metabolites for epigenetic reprogramming. Our findings enhance our understanding of the metastable Zscan4⁺ stem cell state with potential applications in regenerative medicine.

Exercise with food withdrawal at thermoneutrality impacts fuel use, the microbiome, AMPK phosphorylation, muscle fibers, and thyroid hormone levels in rats

Exercise under fasting conditions induces a switch to lipid metabolism, eliciting beneficial metabolic effects. Knowledge of signaling responses underlying metabolic adjustments in such conditions may help to identify therapeutic strategies. Therefore, we studied the effect of mild exercise on rats submitted to food withdrawal at thermoneutrality (28°C) for 3 days. Animals were housed at thermoneutrality rather than the standard housing temperature (22°C) to avoid beta-adrenergic signaling responses that themselves affect metabolism and well-being. Quantitative analysis of multi-organ mRNA levels, myofibers, and serum metabolites shows that this protocol (a) boosts fat oxidation in muscle and liver, (b) reduces lipogenesis and increases gluconeogenesis in liver, (c) increases serum acylcarnitines (especially C4 OH) and ketone bodies and the use of the latter as fuel in muscle, (d) increases Type I myofibers, and (e) is associated with an increased thyroid hormone uptake and metabolism in muscle. In addition, stool microbiome DNA analysis revealed that food withdrawal dramatically alters the presence of bacterial genera associated with ketone metabolism. Taken together, this protocol induces a drastic switch toward increased lipid and ketone metabolism compared to exercise or food withdrawal alone, which may prove beneficial and may involve local thyroid hormones, which may be regarded as exercise mimetics.

Influence of Sex on Urinary Organic Acids: A Cross-Sectional Study in Children

The characterization of urinary metabolome, which provides a fingerprint for each individual, is an important step to reach personalized medicine. It is influenced by exogenous and endogenous factors; among them, we investigated sex influences on 72 organic acids measured through GC-MS analysis in the urine of 291 children (152 males; 139 females) aging 1–36 months and stratified in four groups of age. Among the 72 urinary metabolites, in all age groups, 4-hydroxy-butirate and homogentisate are found only in males, whereas 3-hydroxy-dodecanoate, methylcitrate, and phenylacetate are found only in females. Sex differences are still present after age stratification being more numerous during the first 6 months of life. The most relevant sex differences involve the mitochondria homeostasis. In females, citrate cycle, glyoxylate and dicarboxylate metabolism, alanine, aspartate, glutamate, and butanoate metabolism had the highest impact. In males, urinary organic acids were involved in phenylalanine metabolism, citrate cycle, alanine, aspartate and glutamate metabolism, butanoate metabolism, and glyoxylate and dicarboxylate metabolism. In addition, age specifically affected metabolic pathways, the phenylalanine metabolism pathway being affected by age only in males. Relevantly, the age-influenced ranking of metabolic pathways varied in the two sexes. In conclusion, sex deeply influences both quantitatively and qualitatively urinary organic acids levels, the effect of sex being age dependent. Importantly, the sex effects depend on the single organic acid; thus, in some cases the urinary organic acid reference values should be stratified according the sex and age.

A Phospholipid Profile at 4 Months Predicts the Onset of Celiac Disease in at-Risk Infants

Celiac disease (CeD) is a multifactorial disease influenced by both genetic and environmental risk factors. CeD genetic components are mainly due to HLA class II genes, which account for approximately 40% of the disease heritability. The environmental factor is linked to gliadin ingestion. Despite genetic and epigenetic studies, the pathological molecular mechanism remains unclarified. The strong genetic component does not explain more than half of the hereditability; we identified several epigenetic features that contribute to the understanding of the missing hereditability. The lipid profile of infants has been proposed as a potential biomarker of CeD metabolism that can be measured before they exhibit developmental disorders and clinical symptoms. We suggest that the state of the host is a main factor for the abnormal immune response to gluten. Long before any exposure to the offending agent or any production of specific antibodies, several molecular mechanisms are differentially expressed in infants who will develop CeD compared to their peers matched for the same genetic profile. The present study explored the serum phospholipid profile of a group of infants at risk for celiac disease, followed up to 8 years to monitor the onset of CeD. We compared 30 patients who developed the disease with 20 age- and sex-matched peers with similar genetic profiles who did not develop the disease within 8 years. Serum phospholipids were analysed at 4 months, before exposure to gluten, and at 12 months of age, when none showed any marker of disease. In the 30 CeD patients, we also analysed the serum at the time of diagnosis (>24 months). The serum phospholipid profile was fairly constant across 4 and 12 months of age and, in CeD, up to 24–36 months. The phospholipid signature was dramatically different in infants who developed CeD when compared to that of control NY-CeD (Not Yet developing Celiac Disease) peers. We identified a specific serum phospholipid signature that predicts the onset of celiac disease in HLA at-risk infants years before the appearance of antibodies specific for CeD in the serum and before any clinical symptoms, even before gluten introduction into the diet at 4 months. Specifically, lysophosphatidylcholine, phosphatidylcholine, alkylacyl-phosphatidylcholine, phosphoethanolamines, phosphatidylserines, phosphatidylglycerol and phosphatidylinositol were found to be differentially represented in CeD versus NY-CeD. A set constituted by a limited number of alkylacyl-phosphatidylcholine and lyso-phosphatidylcholine, together with the duration of breast-feeding, allows the discrimination of infants who develop celiac disease before 8 years of age from those at a similar genetic risk who do not develop the disease. In addition to recent discovery, our paper unveiled a specifc phopholipid profile, able to discriminate infants who eventually develop celiac disease years before antibodies or clinical symptoms ensue.

Sex-Gender Variable: Methodological Recommendations for Increasing Scientific Value of Clinical Studies

There is a clear sex-gender gap in the prevention and occurrence of diseases, and in the outcomes and treatments, which is relevant to women in the majority of cases. Attitudes concerning the enrollment of women in randomized clinical trials have changed over recent years. Despite this change, a gap still exists. This gap is linked to biological factors (sex) and psycho-social, cultural, and environmental factors (gender). These multidimensional, entangled, and interactive factors may influence the pharmacological response. Despite the fact that regulatory authorities recognize the importance of sex and gender, there is a paucity of research focusing on the racial/ethnic, socio-economic, psycho-social, and environmental factors that perpetuate disparities. Research and clinical practice must incorporate all of these factors to arrive at an intersectional and system-scenario perspective. We advocate for scientifically rigorous evaluations of the interplay between sex and gender as key factors in performing clinical trials, which are more adherent to real-life. This review proposes a set of 12 rules to improve clinical research for integrating sex-gender into clinical trials.

Label-Free Quantitative Proteomics in a Methylmalonyl-CoA Mutase-Silenced Neuroblastoma Cell Line

Methylmalonic acidemias (MMAs) are inborn errors of metabolism due to the deficient activity of methylmalonyl-CoA mutase (MUT). MUT catalyzes the formation of succinyl-CoA from methylmalonyl-CoA, produced from propionyl-CoA catabolism and derived from odd chain fatty acids β-oxidation, cholesterol, and branched-chain amino acids degradation. Increased methylmalonyl-CoA levels allow for the presymptomatic diagnosis of the disease, even though no approved therapies exist. MMA patients show hyperammonemia, ketoacidosis, lethargy, respiratory distress, cognitive impairment, and hepatomegaly. The long-term consequences concern neurologic damage and terminal kidney failure, with little chance of survival. The cellular pathways affected by MUT deficiency were investigated using a quantitative proteomics approach on a cellular model of MUT knockdown. Currently, a consistent reduction of the MUT protein expression was obtained in the neuroblastoma cell line (SH-SY5Y) by using small-interfering RNA (siRNA) directed against an MUT transcript (MUT siRNA). The MUT absence did not affect the cell viability and apoptotic process in SH-SY5Y. In the present study, we evaluate and quantify the alterations in the protein expression profile as a consequence of MUT-silencing by a mass spectrometry-based label-free quantitative analysis, using two different quantitative strategies. Both quantitative methods allowed us to observe that the expression of the proteins involved in mitochondrial oxido-reductive homeostasis balance was affected by MUT deficiency. The alterated functional mitochondrial activity was observed in siRNA_MUT cells cultured with a propionate-supplemented medium. Finally, alterations in the levels of proteins involved in the metabolic pathways, like carbohydrate metabolism and lipid metabolism, were found.

Metabolic Profiling of Eccentric Exercise-Induced Muscle Damage in Human Urine

Skeletal muscle can be ultrastructurally damaged by eccentric exercise, and the damage causes metabolic disruption in muscle. This study aimed to determine changes in the metabolomic patterns in urine and metabolomic markers in muscle damage after eccentric exercise. Five men and 6 women aged 19~23 years performed 30 min of the bench step exercise at 70 steps per min at a determined step height of 110% of the lower leg length, and stepping frequency at 15 cycles per min. ¹H NMR spectral analysis was performed in urine collected from all participants before and after eccentric exercise-induced muscle damage conventionally determined using a visual analogue scale (VAS) and maximal voluntary contraction (MVC). Urinary metabolic profiles were built by multivariate analysis of principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA) using SIMCA-P. From the OPLS-DA, men and women were separated 2 hr after the eccentric exercise and the separated patterns were maintained or clarified until 96 hr after the eccentric exercise. Subsequently, urinary metabolic profiles showed distinct trajectory patterns between men and women. Finally, we found increased urinary metabolites (men: alanine, asparagine, citrate, creatine phosphate, ethanol, formate, glucose, glycine, histidine, and lactate; women: adenine) after the eccentric exercise. These results could contribute to understanding metabolic responses following eccentric exercise-induced muscle damage in humans.

Immune function? A missing link in the gender disparity in preterm neonatal outcomes

INTRODUCTION

In neonatology, males exhibit a more severe disease course and poorer prognosis in many pathological states when compared to females. Perinatal brain injury, respiratory morbidity, and sepsis, among other complications, preferentially affect males. Preterm neonates (born <37 weeks gestation) display a particularly marked sexual disparity in pathology, especially at the borders of viability. The sex biases in preterm neonatal outcomes and underlying multifactorial mechanisms have been incompletely explored. Sex-specific clinical phenomena may be partially explained by intrinsic differences in immune function. The distinct immune system of preterm neonates renders this patient population vulnerable, and it is increasingly important to consider biological sex in disease processes and to strive for improved outcomes for both sexes. Areas covered: We discuss the cellular responses and molecular intermediates in immune function which are strongly dependent on sex-specific factors such as the genetic and hormonal milieu of premature birth and consider novel findings in a clinical context. Expert commentary: The role of immune function in the manifestation of sex-specific disease manifestations and outcomes in preterm neonates is a critical prognostic variable. Further mechanistic elucidation will yield valuable translational and clinical information of disease processes in preterm neonates which may be harnessed for modulation.

Metabolomic signatures of low birthweight: Pathways to insulin resistance and oxidative stress

Several studies suggest that low birthweight resulting from restricted intrauterine growth can leave a metabolic footprint which may persist into adulthood. To investigate this, we performed metabolomic profiling on 5036 female twins, aged 18-80, with weight at birth information available from the TwinsUK cohort and performed independent replication in two additional cohorts. Out of 422 compounds tested, 25 metabolites associated with birthweight in these twins, replicated in 1951 men and women from the Hertfordshire Cohort Study (HCS, aged 66) and in 2391 men and women from the North Finland Birth 1986 cohort (NFBC, aged 16). We found distinct heterogeneity between sexes and, after adjusting for multiple tests and heterogeneity, two metabolites were reproducible overall (propionylcarnitine and 3-4-hydroxyphenyllactate). Testing women only, we found other metabolites associated with lower birthweight from the meta-analysis of the three cohorts (2-hydroxy-butyric acid and γ-glutamylleucine). Higher levels of all these metabolites can be linked to insulin resistance, oxidative stress or a dysfunction of energy metabolism, suggesting that low birthweight in both twins and singletons are having an impact on these pathways in adulthood.

Targeted metabolomic profiling in rat tissues reveals sex differences

Sex differences affect several diseases and are organ-and parameter-specific. In humans and animals, sex differences also influence the metabolism and homeostasis of amino acids and fatty acids, which are linked to the onset of diseases. Thus, the use of targeted metabolite profiles in tissues represents a powerful approach to examine the intermediary metabolism and evidence for any sex differences. To clarify the sex-specific activities of liver, heart and kidney tissues, we used targeted metabolomics, linear discriminant analysis (LDA), principal component analysis (PCA), cluster analysis and linear correlation models to evaluate sex and organ-specific differences in amino acids, free carnitine and acylcarnitine levels in male and female Sprague-Dawley rats. Several intra-sex differences affect tissues, indicating that metabolite profiles in rat hearts, livers and kidneys are organ-dependent. Amino acids and carnitine levels in rat hearts, livers and kidneys are affected by sex: male and female hearts show the greatest sexual dimorphism, both qualitatively and quantitatively. Finally, multivariate analysis confirmed the influence of sex on the metabolomics profiling. Our data demonstrate that the metabolomics approach together with a multivariate approach can capture the dynamics of physiological and pathological states, which are essential for explaining the basis of the sex differences observed in physiological and pathological conditions.

Sex in basic research: concepts in the cardiovascular field

Women and men, female and male animals and cells are biologically different, and acknowledgement of this fact is critical to advancing medicine. However, incorporating concepts of sex-specific analysis in basic research is largely neglected, introducing bias into translational findings, clinical concepts and drug development. Research funding agencies recently approached these issues but implementation of policy changes in the scientific community is still limited, probably due to deficits in concepts, knowledge and proper methodology. This expert review is based on the EUGenMed project (www.eugenmed.eu) developing a roadmap for implementing sex and gender in biomedical and health research. For sake of clarity and conciseness, examples are mainly taken from the cardiovascular field that may serve as a paradigm for others, since a significant amount of knowledge how sex and oestrogen determine the manifestation of many cardiovascular diseases (CVD) has been accumulated. As main concepts for implementation of sex in basic research, the study of primary cell and animals of both sexes, the study of the influence of genetic vs. hormonal factors and the analysis of sex chromosomes and sex specific statistics in genome wide association studies (GWAS) are discussed. The review also discusses methodological issues, and analyses strength, weaknesses, opportunities and threats in implementing sex-sensitive aspects into basic research.

Effects of Plant Oil Interesterified Triacylglycerols on Lipemia and Human Health

The position of the fatty acids (sn-1, sn-2 and sn-3) (stereospecific numbering (sn)) in triacylglycerol (TAG) molecules produces a characteristic stereospecificity that defines the physical properties of the fats and influences their absorption, metabolism and uptake into tissues. Fat interesterification is a process that implies a positional distribution of fatty acids (FAs) within the TAG molecules, generating new TAG species, without affecting the FA cis-trans natural balance. The interesterified (IE) fats, frequently used in the food industry comprise fats that are rich in long-chain saturated FAs, such as palmitic acid (16:0) and stearic acid (18:0). Within the interesterified fats, a critical role is played by FA occupying the sn-2 position; in fact, the presence of an unsaturated FA in this specific position influences early metabolic processing and postprandial clearance that in turn could induce atherogenesis and thrombogenesis events. Here, we provide an overview on the role of TAG structures and interesterified palmitic and stearic acid-rich fats on fasting and postprandial lipemia, focusing our attention on their physical properties and their effects on human health.

Cord Blood Metabolome Is Highly Associated with Birth Weight, but Less Predictive for Later Weight Development

BACKGROUND/AIMS

Fetal metabolism may be changed by the exposure to maternal factors, and the route to obesity may already set in utero. Cord blood metabolites might predict growth patterns and later obesity. We aimed to characterize associations of cord blood with birth weight, postnatal weight gain, and BMI in adolescence.

METHODS

Over 700 cord blood samples were collected from infants participating in the German birth cohort study LISAplus. Glycerophospholipid fatty acids (GPL-FA), polar lipids, non-esterified fatty acids (NEFA), and amino acids were analyzed with a targeted, liquid chromatography-tandem mass spectrometry based metabolomics platform. Cord blood metabolites were related to growth factors by linear regression models adjusted for confounding variables.

RESULTS

Cord blood metabolites were highly associated with birth weight. Lysophosphatidylcholines C16:1, C18:1, C20:3, C18:2, C20:4, C14:0, C16:0, C18:3, GPL-FA C20:3n-9, and GPL-FA C22:5n-6 were positively related to birth weight, while higher cord blood concentrations of NEFA C22:6, NEFA C20:5, GPL-FA C18:3n-3, and PCe C38:0 were associated with lower birth weight. Postnatal weight gain and BMI z-scores in adolescents were not significantly associated with cord blood metabolites after adjustment for multiple testing.

CONCLUSION

Potential long-term programming effects of the intrauterine environment and metabolism on later health cannot be predicted with profiling of the cord blood metabolome.