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The pathogenesis of migraine, as well as cluster headache (CH), is yet a debated question. In this review, we discuss the possible role of tyrosine and tryptophan metabolism in the pathogenesis of primary headaches, including the abnormalities in the synthesis of neurotransmitters. High level of dopamine, low level of norepinephrine, and very elevated levels of octopamine and synephrine were found in the plasma of episodic migraine without aura. We hypothesize that the imbalance between the levels of neurotransmitters and elusive amines synthesis is due to a metabolic shift directing tyrosine toward increased decarboxylase and reduced hydroxylase enzyme activities, favored by a state of neuronal hyperexcitability and a reduced mitochondrial activity. In addition, we present biochemical studies performed in chronic migraine (CM) and chronic tension-type headache patients (CTTH) to verify if the same anomalies are present in these primary headaches and, if so, their possible role in the chronicity process of CM and CTTH. The results show that important abnormalities of tyrosine-related metabolites are present only in CM patients while tryptamine plasma levels were found significantly lower in both CM and CTTH patients. Because of this, we propose that migraine and, possibly, CH attacks derive from neurotransmitter and neuromodulator metabolic abnormalities in a hyperexcitable and hypoenergetic brain that spread from the frontal lobe, downstream, resulting in abnormally activated nuclei of the pain matrix. The low tryptamine plasma levels found in CM and CTTH patients suggest that these two primary chronic headaches are characterized by a common insufficient serotoninergic control of the pain threshold. [ABSTRACT FROM AUTHOR]

Background and aim: The pathogenesis of the pain that occurs in episodic migraine attack is due to the activation of the trigeminal system's first neuron receptors located on vessel wall. The release from the endothelium of nitric oxide, a product of arginine metabolism, causes vasodilation and stretching of the vascular trigeminal system and promotes pain. It is unknown whether this same metabolic event is involved in the pain accompanying chronic migraine. To understand the possible role of arginine in the pathogenesis of chronic migraine patients, we evaluated the metabolism of arginine in plasma of chronic migraine and control subjects. Methods: We evaluated the metabolism of arginine in a group of patients affected by chronic migraine. Quantification of arginine, ornithine, citrulline, monomethyl arginine (NMMA), dimethylarginines (ADMA, SDMA), and tyramine was performed by ultra-performance liquid chromatography coupled with a triple quadrupole mass spectrometer. Results: Chronic migraine patients showed low plasma levels of arginine, significantly elevated levels of ornithine, ADMA, and NMMA whereas the levels of citrulline and SDMA were in the range of controls. Conclusions: The elevated levels of ADMA and NMMA, inhibitors of nitric oxide synthase, suggest that the metabolism of arginine may be inhibited with a possible reduction of NO release in the circulation of chronic patients. This suggests that the origin of pain may not be related to the vasodilation of trigeminal vascular system that occurs in episodic migraine patients. [ABSTRACT FROM AUTHOR]

Objective: To describe the role of biochemical anomalies of tyrosine (TYR), tryptophan (TRP), and arginine (ARG) metabolism in patients suffering from episodic and chronic cluster headache (CCH). Background: The pathogenesis of cluster headache (CH) and the process that transforms the episodic into the chronic form are unknown. However, the accompanying symptoms suggest a dysfunction of the sympathetic system and hypothalamus along with anomalies of metabolism of catecholamines, elusive amines, and nitric oxide (NO) metabolism. Methods: We describe the results obtained from the last papers published on this issue. The level of metabolites were analyzed by different high‐performance liquid chromatography methods. Results: In both episodic and CH patients, the levels of dopamine and elusive amines are very elevated. The only biochemical difference found in studies between episodic and chronic cluster was that norepinephrine levels were significantly lower in episodic cluster in comparison to control and chronic subjects. In addition, the levels of ARG, homoarginine, and citrulline, precursors of synthesis of NO, were significantly lower in chronic cluster. Conclusions: All these results suggest that TYR, TRP, and ARG metabolism is abnormal and may constitute a biochemical fingerprint of CH patients. The increased levels of norepinephrine in chronic cluster constitute a possible cause of chronicity of this primary headache. The high levels of tryptamine and its activity on the central serotoninergic system may explain why the length of CH is brief in comparison to migraine and tension‐type headache. The low levels of ARG, homoarginine, and citrulline may be the consequence of high circulating levels of α1‐agonists, such as epinephrine and norepinephrine, and their biochemical interaction with endothelial trace amine‐associated receptor 1 that induces activation of NO synthase, resulting in NO synthesis in the circulation, NO release, intense vasodilation, and as a result, the cluster attack. [ABSTRACT FROM AUTHOR]

Aim of the study: The lung architecture of newborns appears to be affected by an inflammatory reaction to maternal choriodecidual layer infection. L-citrulline (L-Cit) was administered to pregnant rats exposed to intra-amniotic lipopolysaccharide (LPS)-induced chorioamnionitis to investigate its effect on neonatal lung injury. Materials and Methods: The pups were assigned to four experimental groups: 1- pups exposed to intra-amniotic NaCl but not to postnatal L-Cit (Controls); 2 - pups exposed to intra-amniotic NaCl as well as to postnatal L-Cit treatment (L-Cit group); 3 - pups exposed to prenatal LPS but not to postnatal (LPS); 4- pups exposed to prenatal LPS as well as to postnatal L-Cit treatment (LPS + L-Cit). Some pups in each group were sacrificed on postnatal (P) day 3 and others on day 7. The pups' lungs were harvested for morphometric analysis; cytokine, arginase 1, and VEGF values were quantified. Serum arginine, citrulline, asymmetric dimethylarginine (ADMA), symmetric dimethylarginine, NG-monomethyl arginine, and homoarginine levels were determined using UPLC-MS/MS. Results: L-Cit attenuated the disruption of alveolar growth in the LPS + L-Cit group. Arginine, homo-arginine, and ADMA levels fell in the LPS treated groups. Arginine and ADMA rose at P7 in the L-Cit group whose members also showed higher VEGF levels with respect to the Controls. The Controls, instead, showed higher IL-10 and IL-1β values with respect to the L-Cit group at P7. Arginase 1 was higher in the LPS groups with respect to the Controls at P7. Conclusions: L-Cit improved alveolar and vascular growth diminishing the lung inflammatory response in the newborn rats exposed to intra-amniotic LPS. The ADMA/DDAH/NO pathway appeared to counteract proinflammatory cytokine production and to sustain macrophage migration. [ABSTRACT FROM AUTHOR]

Objective: Using an untargeted metabolomics approach we investigated the metabolome of children with type 1 diabetes (T1D) in comparison with healthy peers and explored the contribution of HbA1c and clinical features to the observed difference. Research Design and Methods: We enrolled children with T1D aged 6‐15 years, attending the pediatric diabetes clinic of University of Padova (Italy). Healthy controls were enrolled on voluntary basis and matched for age, sex, pubertal status, body mass index (BMI). We performed a liquid chromatography and mass spectrometry analysis (LC‐MS) on fasting urinary samples of the 2 groups. Results: A total of 56 patients with T1D aged (11.4 ± 2.2) years, and 30 healthy controls (10.7 ± 2.8) years were enrolled. We identified 59 urinary metabolites having a higher level in children with T1D, mainly represented by gluco‐ and mineralcorticoids, phenylalanine and tryptophan catabolites (kynurenine), small peptides, glycerophospholipids, fatty acids, and gut bacterial products. We did not find any association between HbA1c, pubertal status, disease duration, and metabolome profile within the case group. Conclusions: T1D profoundly disrupts the metabolome of pediatric patients. The excess of cortisol and aldosterone may contribute to the development of macrovascular complications in adulthood, while the increase of tryptophan derivates may have a role in neuronal damage associated to hyperglycemia. Determinants of such findings, other than HbA1c, should be explored. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Asymmetric dimethylarginine (ADMA) competitively inhibits nitric oxide synthase (NOS). Its levels in specimens from murine models and asthmatic patients are related to inflammation and oxidative stress. Patients with cystic fibrosis(CF) reportedly have higher arginase activity, lower NO production and NOS expression than healthy controls. Objective: The objective was to assess the role of ADMA and related metabolites as disease biomarkers in exhaled breath condensate (EBC) of pediatric CF patients, compared with age‐matched healthy controls (HC). Methods: A longitudinal design was conceived and 34 CF patients (21 stable, 13 at the onset of exacerbation) and 16 HC were enrolled. All CF patients underwent clinical examination, spirometry and EBC collection at enrolment; the same tests were performed also after an antibiotic course in those patients with exacerbation. Metabolites levels in EBC were measured with an ultra‐performance liquid chromatography and tandem mass spectrometry technique. Results: All CF patients had ADMA levels (expressed as ratio to tyrosine) similar to those in HC (median 0.0112, IQR 0.0103‐0.0120 and median 0.0114, IQR 0.0090–0.0128, respectively; P = 0.983), while a significant increase in the citrulline/tyrosine ratio was found in CF patients (median 0.6419, IQR 0.5738–0.6899 in CF vs median 0.4176, IQR 0.2986–0.5082 in HC; P = 0.00003). No differences in ADMA levels emerged between stable patients and those with exacerbation. Conclusion: ADMA and related aminoacids were measured simultaneously for the first time in EBC from CF patients. Higher citrulline/tyrosine ratios were found in CF children with normal ADMA levels, suggesting a dysregulated ADMA metabolism in these patients. [ABSTRACT FROM AUTHOR]

ABSTRACT Lysosomal storage disorders comprise a group of rare genetic diseases in which a deficit of specific hydrolases leads to the storage of undegraded substrates in lysosomes. Impaired enzyme activities can be assessed by MS/MS quantification of the reaction products obtained after incubation with specific substrates. In this study, a column-switching HPLC-MS/MS method for multiplex screening in dried blood spot of the lysosomal enzymes activities was developed. Mucopolysaccharidosis type I, Fabry, Gaucher, Krabbe, Niemann-Pick A/B and Pompe diseases were simultaneously assayed. Dried blood spots were incubated with substrates and internal standards; thereafter, supernatants were collected with minor manipulations. Samples were injected, trapped into an online perfusion column and, by a six-port valve, switched online through the C18 analytical column to perform separation of metabolites followed by MS/MS analysis. A total of 1136 de-identified newborn screening samples were analyzed to determine references for enzymes activity values. As positive controls, we analyzed dried blood spots from three patients with Pompe, one with Fabry, one with Krabbe disease and two with MPS I, and in all cases the enzyme activities were below the cutoff values measured for newborns, except for an MPS I patient after successful hematopoietic stem cell transplantation. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Acylcarnitine profiling in dried blood spots (DBS) is a useful method for high-throughput newborn screening of metabolic disorders, but differentiation of isobaric and isomeric compounds is not achievable. Chromatographic methods for separation have already been reported but are specific for short-chain acylcarnitines or time-consuming. The aim of this work was to develop a fast ultraperformance liquid chromatography (UPLC)-tandem mass spectrometry (MS/MS) method for separation and quantification of a large number of acylcarnitines, including dicarboxylic acylcarnitines and hydroxyacylcarnitines, in DBS and plasma samples. Acylcarnitines from DBS and plasma were converted to their butyl esters and analyzed by electrospray ionization MS/MS. Chromatographic separation was achieved using a UPLC system equipped with an ethylene-bridged hybrid C column. The correlation coefficients of the calibration curves ( r) ranged from 0.990 to 0.999. The limit of detection ranged from 0.002 and 0.063 μM for all compounds, and the limit of quantification ranged from 0.004 and 0.357 μM. Precision ranged from 0.8 to 8.8 % and the mean recovery was 103 %. Profiles of acylcarnitine isomers were investigated in specimens obtained from patients diagnosed with different inborn errors of metabolism. Acylcarnitine concentrations were also measured in 58 term newborns and compared with flow injection analysis measurements. With this newly developed UPLC-MS/MS method, the simultaneous detection of 61 (13 of these labeled) acylcarnitines in DBS and plasma can be achieved in 15 min including postrun equilibration. The method has been validated and can be used as an important component of newborn screening methods as a second-tier test for discrimination and to confirm diagnosis. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

We previously found a shorter surfactant disaturated phosphatidylcholine palmitate (DSPCPA) half-life in infants with bronchopulmonary dysplasia (BPD) by using a single stable isotope tracer and simple formulas based on a one-exponential fit of the final portion of the enrichment decay curve. The aim of this study was to apply noncompartmental and compartmental analysis on the entire enrichment decay curve of DSPC-PA and to compare the kinetic data with our previous results. We analyzed 10 preterm newborns with BPD (gestational age 26 ± 0.6 wk, weight 777 ± 199 g) and 6 controls (gestational age 26 ± 1.4 wk, weight 787 ± 259 g). All took part in our previous study. Endotracheal 13C-labeled dipalmitoyl phosphatidylcholine was administered, and the 13C-enrichment of surfactant DSPC-PA was measured from serial tracheal aspirates by gas chromatography-mass spectrometry. Noncompartmental and compartmental models were numerically identified from the tracer-to-tracee ratio and kinetic parameters related to the accessible (pool accessible to sampling, likely to be the lung alveolar pool) and to the nonaccessible pools (pools not accessible to samplings, likely to be the intracellular storage pool) were estimated in the two study groups. Comparison was performed by Mann-Whitney test. A two-compartment model provided the most reliable assessment of DSPC-PA kinetics. In BPD vs. controls, mean ± SE residence time of DSPC-PA in the accessible was 17.5 ± 2.6 vs. 32.2 ± 6.4 h (P < 0.05), whereas it was 49.7 ± 3.5 vs. 54.4 ± 3.9 h (NS, not significant) in the nonaccessible pool; DSPC-PA recycling was 0.26 ± 0.05 vs. 0.43 ± 0.04% (NS), respectively. A two-compartment model of surfactant DSPC-PA kinetics allowed a thorough assessment of DSPC-PA kinetics, including masses, synthesis, and fluxes between pools. The most important findings of this study are that in BPD infants DSPC-PA loss from the alveolar pool was higher and recycling through the intracellular pool lower than in controls. [ABSTRACT FROM AUTHOR]

A "green" solvent-free industrial process (patent pending) is here described for a grape seed extract (GSE) preparation (Ecovitis™) obtained from selected seeds of Veneto region wineries, in the northeast of Italy, by water and selective tangential flow filtration at different porosity. Since a comprehensive, non-ambiguous characterization of GSE is still a difficult task, we resorted to using an integrated combination of gel permeation chromatography (GPC) and electrospray ionization high resolution mass spectrometry (ESI-HRMS). By calibration of retention time and spectroscopic quantification of catechin as chromophore, we succeeded in quantifying GPC polymers up to traces at n = 30. The MS analysis carried out by the ESI-HRMS method by direct-infusion allows the detection of more than 70 species, at different polymerization and galloylation, up to n = 13. This sensitivity took advantage of the nanoscale shotgun approach, although paying the limit of missed separation of stereoisomers. GPC and MS approaches were remarkably well cross-validated by overlapping results. This simple integrated analytical approach has been used for quality control of the production of Ecovitis™. The emerging feature of Ecovitis™ vs. a popular benchmark in the market, produced by a different technology, is the much lower content of species at low n and the corresponding increase of species at high n. [ABSTRACT FROM AUTHOR]

Background: "breathomics" enables indirect analysis of metabolic patterns underlying a respiratory disease. In this study, we analyze exhaled breath condensate (EBC) in asthmatic children before (T0) and after (T1) a three-week course of inhaled beclomethasone dipropionate (BDP). Methods: we recruited steroid-naive asthmatic children for whom inhaled steroids were indicated and healthy children, evaluating asthma control, spirometry and EBC (in asthmatics at T0 and T1). A liquid-chromatography–mass-spectrometry untargeted analysis was applied to EBC and a mass spectrometry-based target analysis to urine samples. Results: metabolomic analysis discriminated asthmatic (n = 26) from healthy children (n = 16) at T0 and T1, discovering 108 and 65 features relevant for the discrimination, respectively. Searching metabolomics databases, seven putative biomarkers with a plausible role in asthma biochemical–metabolic processes were found. After BDP treatment, asthmatic children, in the face of an improved asthma control (p < 0.001) and lung function (p = 0.01), showed neither changes in EBC metabolomic profile nor in urinary endogenous steroid profile. Conclusions: "breathomics" can discriminate asthmatic from healthy children, with prostaglandin, fatty acid and glycerophospholipid as putative markers. The three-week course of BDP—in spite of a significant clinical improvement—was not associated with changes in EBC metabolic arrangement and urinary steroid profile. [ABSTRACT FROM AUTHOR]