Exposure to intrauterine inflammation alters metabolomic profiles in the amniotic fluid, fetal and neonatal brain in the mouse

Increased genital mucosal cytokines in Canadian women associate with higher antigen-presenting cells, inflammatory metabolites, epithelial barrier disruption, and the depletion of L. crispatus

BACKGROUND

Cervicovaginal inflammation has been linked to negative reproductive health outcomes including the acquisition of HIV, other sexually transmitted infections, and cervical carcinogenesis. While changes to the vaginal microbiome have been linked to genital inflammation, the molecular relationships between the functional components of the microbiome with cervical immunology in the reproductive tract are understudied, limiting our understanding of mucosal biology that may be important for reproductive health.

RESULTS

In this study, we used a multi'-omics approach to profile cervicovaginal samples collected from 43 Canadian women to characterize host, immune, functional microbiome, and metabolome features of cervicovaginal inflammation. We demonstrate that inflammation is associated with lower amounts of L. crispatus and higher levels of cervical antigen-presenting cells (APCs). Proteomic analysis showed an upregulation of pathways related to neutrophil degranulation, complement, and leukocyte migration, with lower levels of cornified envelope and cell-cell adherens junctions. Functional microbiome analysis showed reductions in carbohydrate metabolism and lactic acid, with increases in xanthine and other metabolites. Bayesian network analysis linked L. crispatus with glycolytic and nucleotide metabolism, succinate and xanthine, and epithelial proteins SCEL and IVL as major molecular features associated with pro-inflammatory cytokines and increased APCs.

CONCLUSIONS

This study identified key molecular and immunological relationships with cervicovaginal inflammation, including higher APCs, bacterial metabolism, and proteome alterations that underlie inflammation. As APCs are involved in HIV transmission, parturition, and cervical cancer progression, further studies are needed to explore the interactions between these cells, bacterial metabolism, mucosal immunity, and their relationship to reproductive health. Video Abstract.

Fetal effects of mild maternal COVID-19 infection: metabolomic profiling of cord blood

INTRODUCTION

The impact of maternal coronavirus disease 2019 (COVID-19) infection on fetal health remains to be precisely characterized.

OBJECTIVES

Using metabolomic profiling of newborn umbilical cord blood, we aimed to investigate the potential fetal biological consequences of maternal COVID-19 infection.

METHODS

Cord blood plasma samples from 23 mild COVID-19 cases (mother infected/newborn negative) and 23 gestational age-matched controls were analyzed using nuclear magnetic spectroscopy and liquid chromatography coupled with mass spectrometry. Metabolite set enrichment analysis (MSEA) was used to evaluate altered biochemical pathways due to COVID-19 intrauterine exposure. Logistic regression models were developed using metabolites to predict intrauterine exposure.

RESULTS

Significant concentration differences between groups (p-value < 0.05) were observed in 19 metabolites. Elevated levels of glucocorticoids, pyruvate, lactate, purine metabolites, phenylalanine, and branched-chain amino acids of valine and isoleucine were discovered in cases while ceramide subclasses were decreased. The top metabolite model including cortisol and ceramide (d18:1/23:0) achieved an Area under the Receiver Operating Characteristics curve (95% CI) = 0.841 (0.725-0.957) for detecting fetal exposure to maternal COVID-19 infection. MSEA highlighted steroidogenesis, pyruvate metabolism, gluconeogenesis, and the Warburg effect as the major perturbed metabolic pathways (p-value < 0.05). These changes indicate fetal increased oxidative metabolism, hyperinsulinemia, and inflammatory response.

CONCLUSION

We present fetal biochemical changes related to intrauterine inflammation and altered energy metabolism in cases of mild maternal COVID-19 infection despite the absence of viral infection. Elucidation of the long-term consequences of these findings is imperative considering the large number of exposures in the population.

Utilizing Amniotic Fluid Metabolomics to Monitor Fetal Well-Being: A Narrative Review of the Literature

Fetal and perinatal periods are critical phases for long-term development. Early diagnosis of maternal complications is challenging due to the great complexity of these conditions. In recent years, amniotic fluid has risen in a prominent position in the latest efforts to describe and characterize prenatal development. Amniotic fluid may provide real-time information on fetal development and metabolism throughout pregnancy as substances from the placenta, fetal skin, lungs, gastric fluid, and urine are transferred between the mother and the fetus. Applying metabolomics to monitor fetal well-being, in such a context, could help in the understanding, diagnosis, and treatment of these conditions and is a promising area of research. This review shines a spotlight on recent amniotic fluid metabolomics studies and their methods as an interesting tool for the assessment of many conditions and the identification of biomarkers. Platforms in use, such as proton nuclear magnetic resonance (¹H NMR) and ultra-high-performance liquid chromatography (UHPLC), have different merits, and a combinatorial approach could be valuable. Metabolomics may also be used in the quest for habitual diet-induced metabolic signals in amniotic fluid. Finally, analysis of amniotic fluid can provide information on exposure to exogenous substances by detecting the exact levels of metabolites carried to the fetus and associated metabolic effects.

Intra-amniotic inflammation in the mid-trimester of pregnancy is a risk factor for neuropsychological disorders in childhood

OBJECTIVES

Intra-amniotic inflammation is a subclinical condition frequently caused by either microbial invasion of the amniotic cavity or sterile inflammatory stimuli, e.g., alarmins. An accumulating body of evidence supports a role for maternal immune activation in the genesis of fetal neuroinflammation and the occurrence of neurodevelopmental disorders such as cerebral palsy, schizophrenia, and autism. The objective of this study was to determine whether fetal exposure to mid-trimester intra-amniotic inflammation is associated with neurodevelopmental disorders in children eight to 12 years of age.

METHODS

This is a retrospective case-control study comprising 20 children with evidence of prenatal exposure to intra-amniotic inflammation in the mid-trimester and 20 controls matched for gestational age at amniocentesis and at delivery. Amniotic fluid samples were tested for concentrations of interleukin-6 and C-X-C motif chemokine ligand 10, for bacteria by culture and molecular microbiologic methods as well as by polymerase chain reaction for eight viruses. Neuropsychological testing of children, performed by two experienced psychologists, assessed cognitive and behavioral domains. Neuropsychological dysfunction was defined as the presence of an abnormal score (<2 standard deviations) on at least two cognitive tasks.

RESULTS

Neuropsychological dysfunction was present in 45% (9/20) of children exposed to intra-amniotic inflammation but in only 10% (2/20) of those in the control group (p=0.03). The relative risk (RR) of neuropsychological dysfunction conferred by amniotic fluid inflammation remained significant after adjusting for gestational age at delivery [aRR=4.5 (1.07-16.7)]. Of the 11 children diagnosed with neuropsychological dysfunction, nine were delivered at term and eight of them had mothers with intra-amniotic inflammation. Children exposed to intra-amniotic inflammation were found to have abnormalities in neuropsychological tasks evaluating complex skills, e.g., auditory attention, executive functions, and social skills, whereas the domains of reasoning, language, and memory were not affected in the cases and controls.

CONCLUSIONS

Asymptomatic sterile intra-amniotic inflammation in the mid-trimester of pregnancy, followed by a term birth, can still confer to the offspring a substantial risk for neurodevelopmental disorders in childhood. Early recognition and treatment of maternal immune activation in pregnancy may be a strategy for the prevention of subsequent neurodevelopmental disorders in offspring.

Impact of Maternal Obesity on the Gestational Metabolome and Infant Metabolome, Brain, and Behavioral Development in Rhesus Macaques

Maternal gestational obesity is associated with elevated risks for neurodevelopmental disorder, including autism spectrum disorder. However, the mechanisms by which maternal adiposity influences fetal developmental programming remain to be elucidated. We aimed to understand the impact of maternal obesity on the metabolism of both pregnant mothers and their offspring, as well as on metabolic, brain, and behavioral development of offspring by utilizing metabolomics, protein, and behavioral assays in a non-human primate model. We found that maternal obesity was associated with elevated inflammation and significant alterations in metabolites of energy metabolism and one-carbon metabolism in maternal plasma and urine, as well as in the placenta. Infants that were born to obese mothers were significantly larger at birth compared to those that were born to lean mothers. Additionally, they exhibited significantly reduced novelty preference and significant alterations in their emotional response to stress situations. These changes coincided with differences in the phosphorylation of enzymes in the brain mTOR signaling pathway between infants that were born to obese and lean mothers and correlated with the concentration of maternal plasma betaine during pregnancy. In summary, gestational obesity significantly impacted the infant systemic and brain metabolome and adaptive behaviors.

Maternal immune activation in rats induces dysfunction of placental leucine transport and alters fetal brain growth

Maternal infection during pregnancy increases the offspring risk of developing a variety of neurodevelopmental disorders (NDDs), including schizophrenia. While the mechanisms remain unclear, dysregulation of placental function is implicated. We hypothesised that maternal infection, leading to maternal immune activation and stimulated cytokine production, alters placental and yolk sac amino acid transport, affecting fetal brain development and thus NDD risk. Using a rat model of maternal immune activation induced by the viral mimetic polyinosinic:polycytidylic acid (poly(I:C)), we investigated placental and yolk sac expression of system L amino acid transporter subtypes which transport several essential amino acids including branched-chain amino acids (BCAA), maternal and fetal BCAA concentration, placental 14C-leucine transport activity and associated impacts on fetal growth and development. Poly(I:C) treatment increased acutely maternal IL-6 and TNFα concentration, contrasting with IL-1β. Transcriptional responses for these pro-inflammatory cytokines were found in placenta and yolk sac following poly(I:C) treatment. Placental and yolk sac weights were reduced by poly(I:C) treatment, yet fetal body weight was unaffected, while fetal brain weight was increased. Maternal plasma BCAA concentration was reduced 24 h post-poly(I:C) treatment, yet placental, but not yolk sac, BCAA concentration was increased. Placental and yolk sac gene expression of Slc7a5, Slc7a8 and Slc43a2 encoding LAT1, LAT2 and LAT4 transporter subtypes respectively, was altered by poly(I:C) treatment. Placental 14C-leucine transport was significantly reduced 24 h post-treatment, contrasting with a significant increase six days following poly(I:C) treatment. Maternal immune activation induces dysregulated placental transport of amino acids affecting fetal brain development, and NDD risk potential in offspring.

Congenital Infection Influence on Early Brain Development Through the Gut-Brain Axis

The mechanisms by which various pathogens cause congenital infections have been studied extensively, aiding in the understanding of the detrimental effects these infections can have on fetal/neonatal neurological development. Recent studies have focused on the gut-brain axis as pivotal in neurodevelopment, with congenital infections causing substantial disruptions. There remains controversy surrounding the purported sterility of the placenta as well as concerns regarding the effects of exposure to antibiotics used during pregnancy on neonatal microbiome development and how early exposure to microbes or antibiotics can shape the gut-brain axis. Long-term neurodevelopmental consequences, such as autism spectrum disorder, attention deficit hyperactivity disorder, and cerebral palsy, may be attributable, in part, to early life infection and changes in the immature gut microbiome. The goal of this review is thus to critically evaluate the current evidence related to early life infection affecting neurodevelopment through the gut-brain axis.

Prenatal inflammation causes obesity and abnormal lipid metabolism via impaired energy expenditure in male offspring

INTRODUCTION

Obesity has becoming a global health issue. Fetus exposed to adversity in the uterine are susceptible to unhealth stimulus in adulthood. Prenatal inflammation is related to poor neonatal outcomes like neurodevelopmental impairments and respiratory complications. Recent studies suggested prenatal lipopolysaccharide (LPS) exposure could result in metabolic disorders. Thus, we hypothesized that offspring exposed to prenatal inflammation could develop into metabolic disorder.

METHODS

The pregnant C57BL/6J mice were intraperitoneally injected with 50 μg/kg LPS or saline only once at GD15. The male offspring were weighted weekly until sacrificed. Indirect calorimetry and body composition were both performed at 9 and 18 weeks old. At 20 weeks old, mice were fasted overnight before collecting blood samples and liver for metabolomics analysis and RNA sequencing, respectively. Differentially expressed genes were further verified by RT-qPCR and western blotting.

RESULTS

Prenatal inflammation resulted in obesity with increased fat percentage and decreased energy expenditure in middle-age male offspring. Abnormal lipid accumulation, changes of gene expression profile and upregulation of multi-component mechanistic target of rapamycin complex 1 (mTOR)/Peroxisome proliferator-activated receptor-γ pathway was observed in liver, accompanied with decreased bile acids level, unsaturated fatty acids androgens and prostaglandins in serum. Indirect calorimetry showed increased respiratory exchange rate and deceased spontaneous activity at 9 weeks in LPS group. Impaired energy expenditure was also observed at 18 weeks in LPS group.

CONCLUSION

Prenatal LPS exposure led to obesity and abnormal lipid metabolism through impaired energy expenditure.

LPS vs. Poly I:C Model: Comparison of Long-Term Effects of Bacterial and Viral Maternal Immune Activation (MIA) on the Offspring

A prominent health issue nowadays is the COVID-19 pandemic, which poses acute risks to human health. However, the long-term health consequences are largely unknown and cannot be neglected. An especially vulnerable period for infection is pregnancy, when infections could have long-term health effect on the child. Evidence suggests that maternal immune activation (MIA) induced by either bacteria or viruses presents various effects on the offspring, leading to adverse phenotypes in many organ systems. This review compares the mechanisms of bacterial and viral MIA and the possible long-term outcomes for the offspring by summarizing the outcome in animal LPS and Poly I:C models. Both models are activated immune responses mediated by Toll-like receptors. The outcomes for MIA offspring include neurodevelopment, immune response, circulation, metabolism, and reproduction. Some of these changes continue to exist until later life. Besides different doses and batches of LPS and Poly I:C, the injection day, administration route, and also different animal species influence the outcomes. Here, we specifically aim to support colleagues when choosing their animal models for future studies.

Emerging Roles of Microglia in Neuro-vascular Unit: Implications of Microglia-Neurons Interactions

Microglia, which serve as the defensive interface of the nervous system, are activated in many neurological diseases. Their role as immune responding cells has been extensively studied in the past few years. Recent studies have demonstrated that neuronal feedback can be shaped by the molecular signals received and sent by microglia. Altered neuronal activity or synaptic plasticity leads to the release of various communication messages from neurons, which in turn exert effects on microglia. Research on microglia-neuron communication has thus expanded from focusing only on neurons to the neurovascular unit (NVU). This approach can be used to explore the potential mechanism of neurovascular coupling across sophisticated receptor systems and signaling cascades in health and disease. However, it remains unclear how microglia-neuron communication happens in the brain. Here, we discuss the functional contribution of microglia to synapses, neuroimmune communication, and neuronal activity. Moreover, the current state of knowledge of bidirectional control mechanisms regarding interactions between neurons and microglia are reviewed, with a focus on purinergic regulatory systems including ATP-P₂RY₁₂R signaling, ATP-adenosine-A₁Rs/A_2ARs, and the ATP-pannexin 1 hemichannel. This review aims to organize recent studies to highlight the multifunctional roles of microglia within the neural communication network in health and disease.

IFNγ-Producing γ/δ T Cells Accumulate in the Fetal Brain Following Intrauterine Inflammation

Intrauterine inflammation impacts prenatal neurodevelopment and is linked to adverse neurobehavioral outcomes ranging from cerebral palsy to autism spectrum disorder. However, the mechanism by which a prenatal exposure to intrauterine inflammation contributes to life-long neurobehavioral consequences is unknown. To address this gap in knowledge, this study investigates how inflammation transverses across multiple anatomic compartments from the maternal reproductive tract to the fetal brain and what specific cell types in the fetal brain may cause long-term neuronal injury. Utilizing a well-established mouse model, we found that mid-gestation intrauterine inflammation resulted in a lasting neutrophil influx to the decidua in the absence of maternal systemic inflammation. Fetal immunologic changes were observed at 72-hours post-intrauterine inflammation, including elevated neutrophils and macrophages in the fetal liver, and increased granulocytes and activated microglia in the fetal brain. Through unbiased clustering, a population of Gr-1+ γ/δ T cells was identified as the earliest immune cell shift in the fetal brain of fetuses exposed to intrauterine inflammation and determined to be producing high levels of IFNγ when compared to γ/δ T cells in other compartments. In a case-control study of term infants, IFNγ was found to be elevated in the cord blood of term infants exposed to intrauterine inflammation compared to those without this exposure. Collectively, these data identify a novel cellular immune mechanism for fetal brain injury in the setting of intrauterine inflammation.

Metabolomics of acid whey derived from Greek yogurt

Acid whey, a byproduct of Greek yogurt production, has little commercial value due to its low protein content and is also environmentally harmful when disposed of as waste. However, as a product of microbial fermentation, acid whey could be a rich source of beneficial metabolites associated with fermented foods. This study increases understanding of acid whey composition by providing a complete metabolomic profile of acid whey. Commercial and laboratory-made Greek yogurts, prepared with 3 different bacterial culture combinations, were evaluated. Samples of uncultured milk and cultured whey from each batch were analyzed. Ultra-high-performance liquid chromatography-tandem mass spectrometry metabolomics were used to separate and identify 477 metabolites. Compared with uncultured controls, acid whey from fermented yogurt showed decreases in some metabolites and increases in others, presumably due to the effects of microbial metabolism. Additional metabolites appeared in yogurt whey but not in the uncultured control. Therefore, the effect of microbial fermentation is complex, leading to increases or decreases in potentially bioactive bovine metabolites while generating new microbial compounds that may be beneficial. Metabolite production was significantly affected by combinations of culturing organisms and production location. Differences between laboratory-made and commercial samples could be caused by different starting ingredients, environmental factors, or both.

Maternal Rat Metabolomics: Amniotic Fluid and Placental Metabolic Profiling Workflows

Studying the metabolome of specific gestational compartments is of growing interest in the context of fetus developmental disorders. However, the metabolomes of the placenta and amniotic fluid (AF) are poorly characterized. Therefore, we present the validation of a fingerprinting methodology. Using pregnant rats, we performed exhaustive and robust extractions of metabolites in the AF and lipids and more polar metabolites in the placenta. For the AF, we compared the extraction capabilities of methanol (MeOH), acetonitrile (ACN), and a mixture of both. For the placenta, we compared (i) the extraction capabilities of dichloromethane, methyl t-butyl ether (MTBE), and butanol, along with (ii) the impact of lyophilization of the placental tissue. Analyses were performed on a C18 and hydrophilic interaction liquid chromatography combined with high-resolution mass spectrometry. The efficiency and the robustness of the extractions were compared based on the number of the features or metabolites (for untargeted or targeted approach, respectively), their mean total intensity, and their coefficient of variation (% CV). The extraction capabilities of MeOH and ACN on the AF metabolome were equivalent. Lyophilization also had no significant impact and usefulness on the placental tissue metabolome profiling. Considering the placental lipidome, MTBE extraction was more informative because it allowed extraction of a slightly higher number of lipids, in higher concentration. This proof-of-concept study assessing the metabolomics and lipidomics of the AF and the placenta revealed changes in both metabolisms, at two different stages of rat gestation, and allowed a detailed prenatal metabolic fingerprinting.

Prenatal inflammation as a link between placental expression signature of tryptophan metabolism and preterm birth

Spontaneous preterm birth is a serious medical condition responsible for substantial perinatal morbidity and mortality. Its phenotypic characteristics, preterm labor with intact membranes (PTL) and preterm premature rupture of the membranes (PPROM), are associated with significantly increased risks of neurological and behavioral alterations in childhood and later life. Recognizing the inflammatory milieu associated with PTL and PPROM, here, we examined expression signatures of placental tryptophan metabolism, an important pathway in prenatal brain development and immunotolerance. The study was performed in a well-characterized clinical cohort of healthy term pregnancies (n = 39) and 167 preterm deliveries (PTL, n = 38 and PPROM, n = 129). Within the preterm group, we then investigated potential mechanistic links between differential placental tryptophan pathway expression, preterm birth and both intra-amniotic markers (such as amniotic fluid interleukin-6) and maternal inflammatory markers (such as maternal serum C-reactive protein and white blood cell count). We show that preterm birth is associated with significant changes in placental tryptophan metabolism. Multifactorial analysis revealed similarities in expression patterns associated with multiple phenotypes of preterm delivery. Subsequent correlation computations and mediation analyses identified links between intra-amniotic and maternal inflammatory markers and placental serotonin and kynurenine pathways of tryptophan catabolism. Collectively, the findings suggest that a hostile inflammatory environment associated with preterm delivery underlies the mechanisms affecting placental endocrine/transport functions and may contribute to disruption of developmental programming of the fetal brain.

Metabolic alterations in a rat model of Takotsubo syndrome

AIMS

Cardiac energetic impairment is a major finding in takotsubo patients. We investigate specific metabolic adaptations to direct future therapies.

METHODS AND RESULTS

An isoprenaline-injection female rat model (versus sham) was studied at day-3; recovery assessed at day-7. Substrate uptake, metabolism, inflammation and remodelling were investigated by 18F-FDG-PET, metabolomics, qPCR and WB. Isolated cardiomyocytes were patch-clamped during stress protocols for redox states of NAD(P)H/FAD or [Ca2+]c, [Ca2+]m and sarcomere length. Mitochondrial respiration was assessed by seahorse/Clark electrode (glycolytic and β-oxidation substrates).Cardiac 18F-FDG metabolic rate was increased in takotsubo (p = 0.006), as were expression of GLUT4-RNA/GLUT1/HK2-RNA and HK activity (all p < 0.05), with concomitant accumulation of glucose- and fructose-6-phosphates (p > 0.0001). Both lactate and pyruvate were lower (p < 0.05) despite increases in LDH-RNA and PDH (p < 0.05 both). β-oxidation enzymes CPT1b-RNA and 3KAT were increased (p < 0.01) but malonyl-CoA (CPT-1 regulator) was upregulated (p = 0.01) with decreased fatty acids and acyl-carnitines levels (p = 0.0001-0.02). Krebs cycle intermediates α-ketoglutarate and succinyl-carnitine were reduced (p < 0.05) as was cellular ATP reporter dihydroorotate (p = 0.003). Mitochondrial Ca2+ uptake during high workload was impaired on day-3 (p < 0.0001), inducing oxidation of NAD(P)H and FAD (p = 0.03) but resolved by day-7. There were no differences in mitochondrial respiratory function, sarcomere shortening or [Ca2+] transients of isolated cardiomyocytes, implying preserved integrity of both mitochondria and cardiomyocyte. Inflammation and remodelling were upregulated - increased CD68-RNA, collagen RNA/protein and skeletal actin RNA (all p < 0.05).

CONCLUSION

Dys-regulation of glucose and lipid metabolic pathways with decreases in final glycolytic and β-oxidation metabolites and reduced availability of Krebs intermediates characterises takotsubo myocardium. The energetic deficit accompanies defective Ca2+ handling, inflammation and upregulation of remodelling pathways, with preservation of sarcomeric and mitochondrial integrity.

TRANSLATIONAL PERSPECTIVE

The simultaneous dysregulation in the glycolytic and beta-oxidation pathways which underlies the energetic deficit of the takotsubo heart supports further testing of currently available metabolic modulators as possible candidates for successful therapy, as well as targeting the inflammatory and remodelling pathways.

Global metabolomic profiling reveals hepatic biosignatures that reflect the unique metabolic needs of late-term mother and fetus

OBJECTIVE

Gestational disorders including preeclampsia, growth restriction and diabetes are characterized, in part, by altered metabolic interactions between mother and fetus. Understanding their functional relevance requires metabolic characterization under normotypic conditions.

METHODS

We performed untargeted metabolomics on livers of pregnant, late-term C57Bl/6J mice (N = 9 dams) and their fetuses (pooling 4 fetuses/litter), using UPLC-MS/MS.

RESULTS

Multivariate analysis of 730 hepatic metabolites revealed that maternal and fetal metabolite profiles were highly compartmentalized, and were significantly more similar within fetuses (ρ_average = 0.81), or within dams (ρ_average = 0.79), than within each maternal-fetal dyad (ρ_average = - 0.76), suggesting that fetal hepatic metabolism is under distinct and equally tight metabolic control compared with its respective dam. The metabolite profiles were consistent with known differences in maternal-fetal metabolism. The reduced fetal glucose reflected its limited capacity for gluconeogenesis and dependence upon maternal plasma glucose pools. The fetal decreases in essential amino acids and elevations in their alpha-keto acid carnitine conjugates reflects their importance as secondary fuel sources to meet fetal energy demands. Whereas, contrasting elevations in fetal serine, glycine, aspartate, and glutamate reflects their contributions to endogenous nucleotide synthesis and fetal growth. Finally, the elevated maternal hepatic lipids and glycerol were consistent with a catabolic state that spares glucose to meet competing maternal-fetal energy demands.

CONCLUSIONS

The metabolite profile of the late-term mouse dam and fetus is consistent with prior, non-rodent analyses utilizing plasma and urine. These data position mouse as a suitable model for mechanistic investigation into how maternal-fetal metabolism adapts (or not) to gestational stressors.

Exploratory and confirmatory analysis to investigate the presence of vaginal metabolome expression of microbial invasion of the amniotic cavity in women with preterm labor using high-performance liquid chromatography

BACKGROUND

Although the influence of microbial invasion of the amniotic cavity on the development of spontaneous preterm delivery is unquestionable, the use of an invasive procedure to diagnose the status of an infection limits its clinical translation.

OBJECTIVE

This study aimed to use exploratory and confirmatory analyses to investigate the presence of vaginal metabolome expression of microbial invasion of the amniotic cavity in women diagnosed as having preterm labor using high-performance liquid chromatography.

STUDY DESIGN

In 140 women with singleton pregnancies and a diagnosis of preterm labor at <34 weeks' gestation, we analyzed vaginal amino acid concentrations using high-performance liquid chromatography. Vaginal samples were collected shortly after the amniocentesis performed at admission to rule out microbial invasion of the amniotic cavity. Data were normalized for the median of all the amino acid concentrations evaluated. Microbial invasion of the amniotic cavity was defined as a positive aerobic or anaerobic amniotic fluid culture for the presence of bacteria or yeast or Ureaplasma species or Mycoplasma hominis in the mycoplasma culture or a positive polymerase chain reaction result for 16S rRNA gene sequence. Exploratory analysis was performed in half of the sample and confirmatory analysis in the other half. We compared vaginal amino acid concentrations between women with and without microbial invasion of the amniotic cavity in both cohorts. The area under the curve with 95% confidence interval values were calculated for vaginal amino acids with significant differences.

RESULTS

In the exploratory cohort (2014-2015), 17 of 76 women (22.3%) had microbial invasion of the amniotic cavity compared with 14 of 72 (19.4%) in the confirmatory cohort (2016-2017). In the exploratory cohort, we found significantly higher amino acid concentrations of vaginal taurine, lysine, and cysteine and significantly lower concentrations of vaginal glutamate, aspartate, and the aspartate to asparagine ratio. These significant differences were confirmed in the confirmatory cohort. The area under the curve of these vaginal amino acids to predict microbial invasion of the amniotic cavity ranged between 0.72 and 0.79, with cysteine being the amino acid with the best performance with an area under the curve of 0.79 (95% confidence interval, 0.71-0.88).

CONCLUSION

We found the vaginal metabolome expression of microbial invasion of the amniotic cavity in women with preterm labor and intact membranes. These findings might open the possibility to develop noninvasive diagnostic tools of microbial invasion of the amniotic cavity with the aim of selecting women who would most likely benefit from an amniocentesis for this indication.

Metabolomics Deciphers Potential Targets of Xuefu Zhuyu Decoction Against Traumatic Brain Injury in Rat

Xuefu Zhuyu decoction (XFZYD) performs multiple functions for traumatic brain injury (TBI) treatment. However, its clinical application is limited by the incomplete exploration of targets and inadequate discussion of mechanisms. We aimed to investigate the metabolic alterations of XFZYD in acute and chronic stages of TBI. Sprague-Dawley rats were randomly divided into the sham, controlled cortical impact (CCI) and XFZYD group. Behavioral and histopathological tests were used to evaluate the neuroprotective effects. Coagulation assays were performed to assess safety. Moreover, we analyzed the metabolomic profiling of hippocampal samples with different time intervals after CCI by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Differential metabolites were screened by multivariate data analysis. To further uncover the association between candidate metabolites and biological interaction networks, we applied bioinformatics analysis using MetaboAnalyst 4.0, STITCH 5.0 and TCMSP. The potential mechanism was verified by ELISA and Western blot. XFZYD ameliorated neurological deficiencies post-CCI without impairing blood coagulation in the rat’s model. Seventeen and fourteen metabolites were filtered on d 3 and 21, respectively. Eleven of potential metabolites were common at these time points, involving two significant pathways (arginine and proline metabolism, phenylalanine, tyrosine and tryptophan biosynthesis). Gamma-aminobutyric acid (GABA) and the related pathways were specifically affected by XFZYD at the acute phase of TBI, while biosynthesis of amino acids was the major pathway influenced at the chronic phase. This study provides broad insights into the therapeutic effects of XFZYD in treating TBI through the whole phases.

Metabolomic Profile of Allantoic and Amniotic Fluid in Late-term Gestational Mares Characterized by 1H-nuclear Magnetic Resonance Spectroscopy

The amniotic and allantoic fluid compartments in the mare serve essential roles throughout pregnancy and parturition. Although the global metabolomic profile of amniotic fluid in women has been extensively characterized, current data for equine fetal fluids are limited. Therefore, the goal of this study was to characterize the global metabolomic profile of equine allantoic and amniotic fluid through nuclear magnetic resonance spectroscopy. Fetal fluids were collected between 270 and 295 days of gestation from 12 pregnancies through ultrasound-guided transabdominal puncture. A total of 24 samples (n = 10 allantoic fluid; n = 9 amniotic fluid; n = 5 admixed fluid) were analyzed by one-dimensional proton (¹H) and two-dimensional (¹H-¹³ C) nuclear magnetic resonance spectroscopy. Metabolites were integrated and compared between fluid types using a Kruskal-Wallis test at P < .05 significance. A total of 28 distinct metabolites were found in allantoic and admixed fluid, whereas 23 metabolites were identified in amniotic fluid. Allantoic fluid contained significant elevations (P < .05) in the metabolites betaine, creatine, creatinine, citrate, histidine, nitrophenol, tryptophan, π-methylhistidine, and unknown metabolite #1 compared with amniotic fluid, whereas amniotic fluid contained statistically increased concentrations of the metabolite lactate compared with allantoic fluid (P = .003).

Maternal Immune Activation in Mice Only Partially Recapitulates the Autism Spectrum Disorders Symptomatology

Prenatal viral/bacterial infections are considered risk factors for autism spectrum disorders (ASD) and rodent models of maternal immune activation (MIA) have been developed and extensively used in preclinical studies. Poly inosinic-cytidylic acid (Poly I:C) was injected in C57BL6/J dams to mimic a viral infection on gestational day 12.5; the experimental design includes 10/12 litters in each treatment group and data were analysed always considering the litter-effect; neonatal (spontaneous motor behaviour and ultrasonic vocalizations) and adult [open field, marble burying, social approach, fear conditioning, prepulse inhibition (PPI)] offspring of both sexes were tested. In vivo magnetic resonance imaging/spectroscopy (MRI-MRS) and high-performance liquid chromatography (HPLC) to quantify both aminoacid and/or neurotransmitter concentration in cortical and striatal regions were also carried out. In both sexes high levels of repetitive motor responses and sensory gating deficits in PPI were the more striking effects of Poly I:C, whereas no alteration of social responses were evidenced. Poly I:C treatment did not affect mean values, but, intriguingly, increased variability in the levels of four aminoacids (aspartate glycine and GABA) selectively in males. As a whole prenatal Poly I:C induced relevant long-term alterations in explorative-stereotyped motor responses and in sensory gating, sparing cognitive and social competences. When systematically assessing differences between male and female siblings within each litter, no significant sex differences were evident except for increased variability of four aminoacid levels in male brains. As a whole, prenatal Poly I:C paradigms appear to be a useful tool to investigate the profound and translationally-relevant effects of developmental immune activation on brain and behavioural development, not necessarily recapitulating the full ASD symptomatology.

Vaginal metabolome: towards a minimally invasive diagnosis of microbial invasion of the amniotic cavity in women with preterm labor

Microbial invasion of the amniotic cavity (MIAC) is only identified by amniocentesis, an invasive procedure that limits its clinical translation. Here, we aimed to evaluate whether the vaginal metabolome discriminates the presence/absence of MIAC in women with preterm labor (PTL) and intact membranes. We conducted a case-control study in women with symptoms of PTL below 34 weeks who underwent amniocentesis to discard MIAC. MIAC was defined as amniotic fluid positive for microorganisms identified by specific culture media. The cohort included 16 women with MIAC and 16 control (no MIAC). Both groups were matched for age and gestational age at admission. Vaginal fluid samples were collected shortly after amniocentesis. Metabolic profiles were analyzed by nuclear magnetic resonance (NMR) spectroscopy and compared using multivariate and univariate statistical analyses to identify significant differences between the two groups. The vaginal metabolomics profile of MIAC showed higher concentrations of hypoxanthine, proline, choline and acetylcholine and decreased concentrations of phenylalanine, glutamine, isoleucine, leucine and glycerophosphocholine. In conclusion, metabolic changes in the NMR-based vaginal metabolic profile are able to discriminate the presence/absence of MIAC in women with PTL and intact membranes. These metabolic changes might be indicative of enhanced glycolysis triggered by hypoxia conditions as a consequence of bacterial infection, thus explaining the utilization of alternative energy sources in an attempt to replenish glucose.

The choice of amniotic fluid in metabolomics for the monitoring of fetus health - update

Introduction: In recent years, several studies have highlighted the promising role of metabolomics in the analysis of amniotic fluid (AF), to describe and characterize the interactions occurring between the mother and the fetus during prenatal development. Among the available biological fluids, AF represents an ideal substrate to provide dynamic information regarding fetal organogenesis and metabolism through pregnancy, since it originates from both maternal and fetal tissues and contains substances derived from placenta, fetal skin, lungs, gastric fluid, and fetal urine. Areas covered: In this paper, we provide an update reporting the most recent results on AF metabolomics in the assessment of feto-maternal health, regarding physiological pregnancies but even fields such as prematurity, bronchopulmonary dysplasia, fetal malformations, chromosomopathies, maternal diseases, placental inflammation or infections, maternal diet or exposure to exogenous substances, according to the literature found on MEDLINE since 2015. Expert opinion: Metabolomics shows a promising role in describing both physiology and disease; the goal would be the identification of biomarkers able to precociously and efficaciously detect pathological conditions, allowing the identification of complicated pregnancy and improving their management. However, this field is under development and its reliability still needs to be clarified, especially through more numerous and accurate studies.

Callosal septa express guidance cues and are paramedian guideposts for human corpus callosum development

The early development and growth of the corpus callosum are supported by several midline transient structures in mammals that include callosal septa (CS), which are present only in the second half of gestation in humans. Here we provide new data that support the guidance role of CS in corpus callosum development, derived from the analysis of 46 postmortem fetal brains, ranging in age from 16 to 40 post conception weeks (PCW). Using immunohistochemical methods, we show the expression pattern of guidance cues ephrinA4 and neogenin, extracellular protein fibronectin, as well as non-activated microglia in the CS. We found that the dynamic changes in expression of guidance cues, cellular and extracellular matrix constituents in the CS correlate well with the growth course of the corpus callosum at midsagittal level. The CS reach and maintain their developmental maximum between 20 and 26 PCW and can be visualized as hypointense structures in the ventral callosal portion with ex vivo (in vitro) T2-weighted 3T magnetic resonance imaging (MRI). The maximum of septal development overlaps with an increase in the callosal midsagittal area, whereas the slow, gradual resolution of CS coincides with a plateau of midsagittal callosal growth. The recognition of CS existence in human fetal brain and the ability to visualize them by ex vivoMRI attributes a potential diagnostic value to these transient structures, as advancement in imaging technologies will likely also enable in vivoMRI visualization of the CS in the near future.

Poly(I:C) alters placental and fetal brain amino acid transport in a rat model of maternal immune activation

PROBLEM

Maternal immune activation (MIA) during pregnancy is associated with increased chances of neurodevelopmental disorders including schizophrenia and autism spectrum disorder (ASD). However, the exact mechanism through which MIA contributes to altered neurodevelopment is unknown. Due to the important role that amino acids play in neurodevelopment, altered amino acid transport could play a role in neurodevelopmental disorders. Indeed, altered plasma concentrations of multiple amino acids have been reported in individuals with ASD or schizophrenia. Therefore, our objective was to determine whether virally mediated MIA induces changes in amino acid transporters in the placenta and fetal brain.

METHOD OF STUDY

Pregnant rats were administered poly(I:C) on gestational day 14, and placental and fetal tissues were collected 6, 24, and 48 hours later. Amino acid transporter expression was measured in the placenta and fetal brain using qPCR, Western blotting, and Simple Western. Free amino acid concentrations in the fetal brain were quantified using HPLC.

RESULTS

Poly(I:C) increased mRNA expression of several amino acid transporters in the placenta and fetal brain over these timepoints. Conversely, poly(I:C) imposed significant decreases in the protein expression of ASCT1 and EAAT2 in placenta and expression of SNAT5, EAAT1, and GLYT1 in fetal brain. Functional consequences of altered transporter expression were demonstrated through widespread changes in the concentrations of free amino acids in the fetal brains.

CONCLUSION

Together, these results represent novel findings with the poly(I:C) MIA model and contribute to the understanding of how MIA during pregnancy potentially leads to neurodevelopmental disorders.

Maternal Inflammation and Neurodevelopmental Programming: A Review of Preclinical Outcomes and Implications for Translational Psychiatry

Early disruptions to neurodevelopment are highly relevant to understanding both psychiatric risk and underlying pathophysiology that can be targeted by new treatments. Much convergent evidence from the human literature associates inflammation during pregnancy with later neuropsychiatric disorders in offspring. Preclinical models of prenatal inflammation have been developed to examine the causal maternal physiological and offspring neural mechanisms underlying these findings. Here we review the strengths and limitations of preclinical models used for these purposes and describe selected studies that have shown maternal immune impacts on the brain and behavior of offspring. Maternal immune activation in mice, rats, nonhuman primates, and other mammalian model species have demonstrated convergent outcomes across methodologies. These outcomes include shifts and/or disruptions in the normal developmental trajectory of molecular and cellular processes in the offspring brain. Prenatal developmental origins are critical to a mechanistic understanding of maternal immune activation-induced alterations to microglia and immune molecules, brain growth and development, synaptic morphology and physiology, and anxiety- and depression-like, sensorimotor, and social behaviors. These phenotypes are relevant to brain functioning across domains and to anxiety and mood disorders, schizophrenia, and autism spectrum disorder, in which they have been identified. By turning a neurodevelopmental lens on this body of work, we emphasize the importance of acute changes to the prenatal offspring brain in fostering a better understanding of potential mechanisms for intervention. Collectively, overlapping results across maternal immune activation studies also highlight the need to examine preclinical offspring neurodevelopment alterations in terms of a multifactorial immune milieu, or immunome, to determine potential mechanisms of psychiatric risk.

Biomarker Identification of Maternal Genistein Exposure Induced Obesity by Metabonomics Analysis

The objective of this study was to confirm the effect of maternal genistein exposure on body weight of male offspring and the metabolic alterations associated with maternal genistein-induced obesity. Pregnant female Sprague-Dawley (SD) rats were supplemented with 300 mg/kg diet of genistein (GEN) or no genistein (CON) throughout pregnancy and lactation. The growth of male offspring was investigated until 12 week age and the mechanism of obesity was studied using metabonomics by ultra performance liquid chromatography and quadrupole time-of-flight (UPLC Q-TOF) MS with electrospray ionization in positive ESI mode (ESI+). Compared with the CON group, body weight, fat pad and food intake of male offspring in GEN group were increased significantly at the age of weeks 10 to 12 (p<0.05). Ten urine principal metabolites contributing to the clusters were identified, including increased 8-Isoprostaglandin F2a, and decreased L-Proline, Betaine, L-Acetylcarnitine, Norsalsolinol, Indoleacrylic acid, L-Tryptophan, Lysophosphatidylcholines (LysoPC) (20 : 4), Lysophosphatidylethanolamines (LysoPE) (18 : 1) and LysoPC (O-18 : 0). Our results confirmed weight-increasing effects of maternal genistein exposure, accompanied by favorable changes in metabolites in the male offspring' urine. Therefore, this research enables us to better understand obesity and predict risk of obesity-related disease by studying metabolites present in the urine.

Metabolomics of mammalian brain reveals regional differences

Background

The mammalian brain is organized into regions with specific biological functions and properties. These regions have distinct transcriptomes, but little is known whether they may also differ in their metabolome. The metabolome, a collection of small molecules or metabolites, is at the intersection of the genetic background of a given cell or tissue and the environmental influences that affect it. Thus, the metabolome directly reflects information about the physiologic state of a biological system under a particular condition. The objective of this study was to investigate whether various brain regions have diverse metabolome profiles, similarly to their genetic diversity. The answer to this question would suggest that not only the genome but also the metabolome may contribute to the functional diversity of brain regions.

Methods

We investigated the metabolome of four regions of the mouse brain that have very distinct functions: frontal cortex, hippocampus, cerebellum, and olfactory bulb. We utilized gas- and liquid- chromatography mass spectrometry platforms and identified 215 metabolites.

Results

Principal component analysis, an unsupervised multivariate analysis, clustered each brain region based on its metabolome content, thus providing the unique metabolic profile of each region. A pathway-centric analysis indicated that olfactory bulb and cerebellum had most distinct metabolic profiles, while the cortical parenchyma and hippocampus were more similar in their metabolome content. Among the notable differences were distinct oxidative-anti-oxidative status and region-specific lipid profiles. Finally, a global metabolic connectivity analysis using the weighted correlation network analysis identified five hub metabolites that organized a unique metabolic network architecture within each examined brain region. These data indicate the diversity of global metabolome corresponding to specialized regional brain function and provide a new perspective on the underlying properties of brain regions.

Conclusion

In summary, we observed many differences in the metabolome among the various brain regions investigated. All four brain regions in our study had a unique metabolic signature, but the metabolites came from all categories and were not pathway-centric.

Electronic supplementary material

The online version of this article (10.1186/s12918-018-0644-0) contains supplementary material, which is available to authorized users.

Metabolomics of the amniotic fluid: Is it a feasible approach to evaluate the safety of Chinese medicine during pregnancy?

The use of Chinese medicines (CMs) during pregnancy has long been a major public health concern. Although CMs have been shown to be effective in treating infertility and preventing miscarriage, their use has been restricted, mainly because of limited knowledge of their potential toxicity. Accurate toxicology data are urgently required to assess whether these CMs are safe for maternal health and fetal development. Amniotic fluid (AF) contains carbohydrates, lipids and phospholipids, urea and proteins, all of which aid in the growth of the fetus and reflect the mother's health status as well. The changes in metabolomic patterns of AF are related to pathophysiological occurrences during the course of pregnancy. In this review, we provide a summary of the research performed in recent years on metabolomic AF samples, and use our previous study as an example to explore the feasibility of metabolomics of AF to evaluate the safety of CMs during pregnancy. We believe that metabolomics of AF play a far more important role than traditional morphology methods in the safety evaluation of CMs for pregnancy, with a higher sensitivity and correlation.

Understanding neonatal hypoxic-ischemic encephalopathy with metabolomics

BACKGROUND

 Hypoxic-ischemic encephalopathy (HIE), a serious complication of perinatal asphyxia, is commonly associated with an unfavorable outcome. In-depth research is important not only for the interpretation of the underlying biological alternations but may also provide the basis for the development of novel diagnostic and therapeutic tools. The application of metabolomics in perinatal asphyxia/HIE is a relatively new approach.

METHODS

 We performed a narrative, non-systematic review in the literature of metabolomic studies involving newborn animals and humans exposed to hypoxia-ischemia or developing perinatal asphyxia/HIE.

RESULTS

 Fifteen animal studies, nine studies in human neonates, and two review articles were evaluated. Changes in the metabolomic profile of newborn animals exposed to hypoxia-ischemia and of asphyxiated neonates with HIE are presented in relation to the underlying pathophysiology. The clinical relevance of these findings is further discussed in a comprehensible to the bedside clinician manner.

CONCLUSIONS

 Metabolomics may provide an explanation for the various metabolic alternations occurring in perinatal asphyxia/HIE, elucidate the biological background of the applied therapeutic interventions and promote the development of novel diagnostic-prognostic biomarkers of the disease. HIPPOKRATIA 2017, 21(3): 115-123.