Luigi Barberini

Metabolomics in newborns with intrauterine growth retardation (IUGR): urine reveals markers of metabolic syndrome

To date, we have little knowledge on the overall metabolic status of neonates with intrauterine growth retardation (IUGR). In the last few years, the analysis of metabolomics has assumed an important clinical role in identifying “disorders” in the metabolic profile of patients. The aim of this work has been to analyze the urine metabolic profiles of neonates with IUGR and compare them with controls to define the metabolic patterns associated with this pathology. To our knowledge, this is the first study of metabolomics performed on neonates with IUGR. Recruited for the study were 26 neonates with IUGR diagnosed in the neonatal period and with weight at birth below the 10th percentile and 30 neonates of proper gestational weight at birth (controls). In the first 24 hours (prior to feeding) (T1) and about 4 days after birth (T2), a urine sample was taken non-invasively from each neonate. The samples were then frozen at −80°C up to the time of the analysis by proton nuclear magnetic resonance spectroscopy (1H-NMR). The data contained in the NMR spectra obtained from the single samples were statistically analyzed using the Principal Components Analysis and the Partial Least Squares-Discriminate Analysis. By means of a multivariate analysis of the NMR spectra obtained, it was possible to highlight the differences between the two groups (IUGRs and controls) owing to the presence of different metabolic patterns. The discriminants in the urine metabolic profiles derived essentially from significant differences in certain metabolites such as: myo-inositol, sarcosine, creatine and creatinine. The metabolomic analysis showed different urine metabolic profiles between neonates with IUGR and controls and made it possible to identify the molecules responsible for such differences.

A metabolomic study of preterm human and formula milk by high resolution NMR and GC/MS analysis: preliminary results

Objective: The aim of the present study was to investigate the metabolic profile of preterm human breast milk (HBM) by using a metabolomic approach. Methods: NMR spectroscopy and GC/MS were used to analyze the water-soluble and lipid fractions extracted from milk samples obtained from mothers giving birth at 26–36 weeks of gestation. For the sake of comparison, preterm formula milk was also studied. Results: The multivariate statistical analysis of the data evidenced biochemical variability both between preterm HBM and commercial milk and within the group of HBM samples. Conclusions: The preliminary results of this study suggest that metabolomics may provide a promising tool to study aspects related to the nutrition and health of preterm infant.

Increase in 20-50 Hz (gamma frequencies) power spectrum and synchronization after chronic vagal nerve stimulation

OBJECTIVE Though vagus nerve stimulation (VNS) is an important option in pharmaco-resistant epilepsy, its mechanism of action remains unclear. The observation that VNS desynchronised the EEG activity in animals suggested that this mechanism could be involved in VNS antiepileptic effects in humans. Indeed VNS decreases spiking bursts, whereas its effects on the EEG background remain uncertain. The objective of the present study is to investigate how VNS affects local and inter regional syncronization in different frequencies in pharmaco-resistant partial epilepsy. METHODS Digital recordings acquired in 11 epileptic subjects 1 year and 1 week before VNS surgery were compared with that obtained 1 month and 1 year after VNS activation. Power spectrum and synchronization were then analyzed and compared with an epileptic group of 10 patients treated with AEDs only. RESULTS VNS decreases the synchronization of theta frequencies (P < 0.01), whereas it increases gamma power spectrum and synchronization (< 0.001 and 0.01, respectively). CONCLUSIONS The reduction of theta frequencies and the increase in power spectrum and synchronization of gamma bands can be related to VNS anticonvulsant mechanism. In addition, gamma modulation could also play a seizure-independent role in improving attentional performances. SIGNIFICANCE These results suggest that some antiepileptic mechanisms affected by VNS can be modulated by or be the reflection of EEG changes.

Metabolomics: a new tool for the neonatologist

Metabolomics enables the parallel assessment of the levels of a broad range of metabolites and has been shown to have a great impact in investigation of physiological status, diagnosing diseases, measuring the response to treatment, discovering biomarkers, identifying perturbed pathways due to disease or treatment, functional genomics. Common analytical techniques applied to metabolomics are nuclear magnetic resonance spectroscopy, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry. The most commonly used biological samples for metabolomics studies are urine, blood plasma or serum. Because of its characteristics and simple non-invasive methods of collection, urine is particularly suited for metabolomic analysis even in small babies. The use of non-invasive techniques is an essential requirement in neonatal medicine, especially in very preterm infants. Little is known about the overall metabolic status of the term and preterm neonate, but it can be currently assessed by metabolomic analysis of urine. Other important applications of metabolomic analysis of urine in the newborn could be the monitoring of postnatal metabolic maturation over time, the identification of biomarkers as early predictors of outcome, and the implementation and monitoring of a tailored management of neonatal disorders. The clinical management of neonates could be probably improved if more information about perinatal and neonatal maturation processes and their metabolic background were available. The metabolomics approach, together with transcriptomics and proteomics, will have substantial impact on development of diagnostics, therapeutics and drug development and may be an important new tool in neonatology.

Clinical application of metabolomics in neonatology

The youngest and more rapidly increasing “omic” discipline, called metabolomics, is the process of describing the phenotype of a cell, tissue or organism through the full complement of metabolites present. Metabolomics measure global sets of low molecular weight metabolites (including amino acids, organic acids, sugars, fatty acids, lipids, steroids, small peptides, vitamins, etc.), thus providing a “snapshot” of the metabolic status of a cell, tissue or organism in relation to genetic variations or external stimuli. The use of metabolomics appears to be a promising tool in neonatology. The management of sick newborns might improve if more information on perinatal/neonatal maturational processes and their metabolic background were available. Urine (“a window on the organism”) is a biofluid particularly suitable for metabolomic analysis in neonatology because it may be collected by using simple, noninvasive techniques and because it may provide valuable diagnostic information. In this review, the authors report the few literature data on neonatal metabolomics, including their personal experience, in the following fields: intrauterine growth restriction, perinatal transition, asphyxia, brain injury and hypothermia, maternal milk evaluation, postnatal maturation, bronchiolitis, sepsis, patent ductus arteriosus, respiratory distress syndrome, nephrouropathies, metabolic diseases, antibiotic treatment, perinatal programming and long-term outcome in extremely low birth-weight infants.

Clinical metabolomics and urinary NGAL for the early prediction of chronic kidney disease in healthy adults born ELBW

Background: Clinical metabolomics is a recent “omic” technology which is defined as a global holistic overview of the personal metabolic status (fingerprinting). This technique allows to prove metabolic differences in different groups of people with the opportunity to explore interactions such as genotype-phenotype and genotype-environment type, whether normal or pathological. Aim: To study chronic kidney injury 1) using urine metabolomic profiles of young adults born extremely low-birth weight (ELBW) and 2) correlating a biomarker of kidney injury, urinary neutrophil gelatinase-associated lipocalin (NGAL), in order to confirm the metabolomic injury profile. Method: Urine samples were collected from a group of 18 people (mean: 24-year-old, std: 4.27) who were born with ELBW and a group of 13 who were born at term appropriate for gestational age (AGA) as control (mean 25-year-old, std: 5.15). Urine samples were analyzed by 1H-nuclear magnetic resonance spectroscopy, and then submitted to unsupervised and supervised multivariate analysis. Urine NGAL (uNGAL) was measured using ARCHITECT (ABBOTT diagnostic NGAL kit). Results: With a multivariate approach and using a supervised analysis method, PLS-DA, (partial least squares discriminant analysis) we could correlate ELBW metabolic profiles with uNGAL concentration. Conversely, uNGAL could not be correlated to AGA. Conclusions: This study demonstrates the relevance of the metabolomic technique as a predictive tool of the metabolic status of exELBW. This was confirmed by the use of uNGAL as a biomarker which may predict a subclinical pathological process in the kidney such as chronic kidney disease.

Metabolomics in paediatric respiratory diseases and bronchiolitis

The metabolic study of an organism may make it possible to monitor, through the metabolites,the physiology and/or pathology of the organism itself. Metabolomics, in the strictest sense, “the set of metabolites, the final products of the genetic expression”. Most clinical chemistry tests available today rely on old technologies that measure only a single chemical in blood, urine or other biofluids, and these tests are neither sensitive nor specific for any particular disease. Metabolomics offers a holistic approach to systems medicine, with the promise to enhance clinical chemistry diagnostics in several pathologic conditions. The present review covers the application of clinical metabolomics in three different areas of respiratory diseases in pediatrics: asthma, pneumonia and bronchiolitis. Comparison between two 1H-NMR urine spectra by two bronchiolitis patients are also presented.

Accumulation of neutral lipids in peripheral blood mononuclear cells as a distinctive trait of Alzheimer patients and asymptomatic subjects at risk of disease

BackgroundAlzheimers disease is the most common progressive neurodegenerative disease. In recent years, numerous progresses in the discovery of novel Alzheimers disease molecular biomarkers in brain as well as in biological fluids have been made. Among them, those involving lipid metabolism are emerging as potential candidates. In particular, an accumulation of neutral lipids was recently found by us in skin fibroblasts from Alzheimers disease patients. Therefore, with the aim to assess whether peripheral alterations in cholesterol homeostasis might be relevant in Alzheimers disease development and progression, in the present study we analyzed lipid metabolism in plasma and peripheral blood mononuclear cells from Alzheimers disease patients and from their first-degree relatives.MethodsBlood samples were obtained from 93 patients with probable Alzheimers disease and from 91 of their first-degree relatives. As controls we utilized 57, cognitively normal, over-65 year-old volunteers and 113 blood donors aged 21-66 years, respectively. Data are reported as mean ± standard error. Statistical calculations were performed using the statistical analysis software Origin 8.0 version. Data analysis was done using the Student t-test and the Pearson test.ResultsData reported here show high neutral lipid levels and increased ACAT-1 protein in about 85% of peripheral blood mononuclear cells freshly isolated (ex vivo) from patients with probable sporadic Alzheimers disease compared to about 7% of cognitively normal age-matched controls. A significant reduction in high density lipoprotein-cholesterol levels in plasma from Alzheimers disease blood samples was also observed. Additionally, correlation analyses reveal a negative correlation between high density lipoprotein-cholesterol and cognitive capacity, as determined by Mini Mental State Examination, as well as between high density lipoprotein-cholesterol and neutral lipid accumulation. We observed great variability in the neutral lipid-peripheral blood mononuclear cells data and in plasma lipid analysis of the subjects enrolled as Alzheimers disease-first-degree relatives. However, about 30% of them tend to display a peripheral metabolic cholesterol pattern similar to that exhibited by Alzheimers disease patients.ConclusionWe suggest that neutral lipid-peripheral blood mononuclear cells and plasma high density lipoprotein-cholesterol determinations might be of interest to outline a distinctive metabolic profile applying to both Alzheimers disease patients and asymptomatic subjects at higher risk of disease.

A metabolomic approach in an experimental model of hypoxia-reoxygenation in newborn piglets: urine predicts outcome

Perinatal asphyxia is one of the leading causes of morbidity and mortality in the neonatal period. Response to oxygen treatment is unpredictable and the optimum concentration of oxygen in neonatal resuscitation is still a matter of debate among neonatologists. A metabolomic approach was used to characterize the metabolic profiles of newborn hypoxic-reoxygenated piglets. Urine samples were collected from newborn piglets (n = 40) undergoing hypoxia followed by resuscitation at different oxygen concentrations (ranging from 18% to 100%) and analyzed by 1H NMR spectroscopy. Despite reoxygenation 7 piglets, out of 10 which became asystolic, did not respond to resuscitation. Profiles of the 1H NMR spectra were submitted to unsupervised (principal component analysis) and supervised (partial least squares-discriminant analysis) multivariate analysis. The supervised analyses showed differences in the metabolic profile of the urine collected before the induction of hypoxia between survivors and deaths. Metabolic variations were observed in the urine of piglets treated with different oxygen concentrations comparing T0 (basal value) and end of the experiment (resuscitation). Some of the individual metabolites discriminating between these groups were urea, creatinine, malonate, methylguanidine, hydroxyisobutyric acid. The metabolomic approach appears a promising tool for investigating newborn hypoxia over time, for monitoring the response to the treatment with different oxygen concentrations, and might lead to a tailored management of the disorder.

Beta and Gamma Range EEG Power‐Spectrum Correlation with Spiking Discharges in DBA/2J Mice Absence Model: Role of GABAB Receptors

Summary:  Purpose: To describe the correlations between spiking pattern and EEG power spectrum frequency in DBA/2J mice, a model for murine absence seizures, after γ‐aminobutyric acid (GABA)B modulation.