Untargeted metabolomic study by liquid chromatography-mass spectrometry in brain tissues on the effects of combined cocaine and ethanol self-administration in male and female young rats

The combined use of ethanol and cocaine is frequent among drug-abuse users and leads to further exacerbation of health consequences compared to individual consumption and this is of special concern during the transition to adulthood. Despite its high prevalence, the effect of combined consumption of cocaine and ethanol has been scarcely studied. In this work, we report the first untargeted metabolomic study in brain tissues to contribute to the advancement in the knowledge of the possible neurobiological effects of this polysubstance dependence. Liquid Chromatography coupled to high resolution Mass Spectrometry was employed to analyze three different brain tissues samples, prefrontal cortex, striatum and hippocampus, from male and female young rats exposed intravenously to a self-administration of these drugs. After optimizing the best sample treatment and selecting the chromatographic and detection conditions to find the maximum number of significant features (possible biomarker metabolites), the high resolution of the Orbitrap analyzer used in this work has made it possible to find up to 761 significant features with assigned molecular formula, of which up to 190 were tentatively identified and 44 unequivocally confirmed. The results demonstrated that the altered metabolic pathways are involved in multiple functions: receptor systems, such as the Glutamine-Glutamic acid-GABA axis or the catecholamine pathway, purinergic and pyrimidine pathways, fatty acids or oxidative stress, among others.

Stability-Indicating Method Development and Validation for Quantitative Estimation of Assay and Organic Impurities of anti-viral drug Baloxavir-Marboxil in Drug Substance and Pharmaceutical Dosage Form using HPLC and LC-MS Methods

Baloxavir-Marboxil (BXM) is a polymerase-acidic-endonuclease inhibitor used as an anti-viral drug. A simple, reliable, and robust liquid chromatographic method was developed and validated per ICH Q2(R1) for estimating the assay and impurities of BXM in drug substance and pharmaceutical formulations. The chromatographic separation was carried-out on C₁₈ (100 x 4.6 mm, 5-μm) with binary solvent delivery system (A:0.1% trifluoroacetic-acid in water; B:0.1% trifluoroacetic-acid in acetonitrile) along with detection wavelength of 260 nm, column temperature of 57°C, flow of 1.2-mL/min and injection volume of 10-μL. All five known impurities and unknown impurities were separated well with resolution >1.7, and were estimated accurately without any interference. Recovered values and regression value were 99.5-101.2% and R² >0.999, respectively. The recovery and linearity studies covered from 50-150% for assay, and quantitation limit (QL) - 120% for five BXM impurities. Stability-indicating property of the HPLC developed method was assessed from the forced degradation studies. The mass spectral data of unknown impurity formed under oxidation stress condition was discussed. The developed method was also successfully utilized for stability samples analysis of drug substance and tablets dosage form.

Untargeted metabolomics as a tool to monitor biocontrol product residues' fate on field-treated Prunus persica

Evidence of chemical plant protection products' (PPPs) long-term impact has been found in all environmental compartments. Therefore, other types of PPPs are developed to complement chemical PPPs like PPPs from natural sources, namely biocontrol products (BPs). Little is known about those new BPs, and it is important to assess their potential long-term environmental impact. Recently, the Environmental Metabolic Footprinting (EMF) approach was developed. It permits studying sample's entire meta-metabolome (endometabolome and xenometabolome) through a kinetics tracking of metabolomes of treated and untreated samples. Those metabolomes are compared time-by-time to estimate the "resilience time" of the samples after treatment. The current study aims to investigate BP residues' dissipation on peach fruits (Prunus persica). For that, an untargeted Liquid Chromatography-Mass Spectrometry metabolomics approach based on the EMF was optimised to separate the xenometabolome of the PPP from the endometabolome of the fruits. This "new version" of the EMF approach is able to target the BP treatment residues' (xenometabolome) dissipation exclusively. Thus, it is able to determine the time needed to have no more residues in the studied matrix: the "dissipation interval". Field experiment was conducted on peach tree orchard against brown rot treated with (i) a plant extract BP (Akivi); (ii) a reference mineral extract BP (Armicarb®); and (iii) a Chemical reference treatment campaign. Formulated Akivi and its by-products' dissipation was monitored, a degradation kinetics appeared but the sampling did not last long enough to allow the determination of the "dissipation interval". Armicarb® and the Chemical reference's residues and by-products showed a persistence pattern along the sampling kinetics. These results indicate that the EMF approach, formerly developed on soil and sediment, is applicable for fruit matrices and can be used to investigate the fate of complex BP treatment on the matrix through the xenometabolome tracking on treated fruits.

Current state-of-the-art of separation methods used in LC-MS based metabolomics and lipidomics

Metabolomics deals with the large-scale analysis of metabolites, belonging to numerous compound classes and showing an extremely high chemical diversity and complexity. Lipidomics, being a subcategory of metabolomics, analyzes the cellular lipid species. Both require state-of-the-art analytical methods capable of accessing the underlying chemical complexity. One of the major techniques used for the analysis of metabolites and lipids is Liquid Chromatography-Mass Spectrometry (LC-MS), offering both different selectivities in LC separation and high sensitivity in MS detection. Chromatography can be divided into different modes, based on the properties of the employed separation system. The most popular ones are Reversed-Phase (RP) separation for non- to mid-polar molecules and Hydrophilic Interaction Liquid Chromatography (HILIC) for polar molecules. So far, no single analysis method exists that can cover the entire range of metabolites or lipids, due to the huge chemical diversity. Consequently, different separation methods have been used for different applications and research questions. In this review, we explore the current use of LC-MS in metabolomics and lipidomics. As a proxy, we examined the use of chromatographic methods in the public repositories EBI MetaboLights and NIH Metabolomics Workbench. We extracted 1484 method descriptions, collected separation metadata and generated an overview on the current use of columns, eluents, etc. Based on this overview, we reviewed current practices and identified potential future trends as well as required improvements that may allow us to increase metabolite coverage, throughput or both simultaneously.

First Profile of Phenolic Compounds from Maltese Extra Virgin Olive Oils Using Liquid-Liquid Extraction and Liquid Chromatography-Mass Spectrometry

This study presents the profile of phenolic extracts from different Extra Virgin Olive Oils (EVOOs) from Malta and is the first study that characterizes the phenolic profile of the Maltese EVOOs Bidni (B) and Malti (M) using liquid-liquid extraction (LLE) and Liquid Chromatography-Mass Spectrometry (LC-MS). The total phenolic content (TPC), ortho diphenolic content (TdPC) and flavonoid content (TFC) were determined using the Folin-Ciocalteau assay, the Arnow's assay and the Aluminium Chloride method respectively. Results show that the B variety had the highest TPC, TdPC and TFC. Using LC-MS analysis, over 30 phenolic compounds were identified belonging to different classes of phenolic compounds.

Mitochondrial lipid profiling data of a traumatic optic neuropathy model

Traumatic optic neuropathy (TON) is a degenerative process that occurs in a subset of patients following blunt force trauma to the head. This condition is characterized by retinal ganglion cell (RGC) death and axon degeneration within the optic nerve [1]. At the cellular level, mitochondrial changes are associated with many optic neuropathies [2, 3]. Here, we provide a dataset demonstrating changes in the optic nerve mitochondrial lipid profile of a sonication-induced traumatic optic neuropathy (SI-TON) mouse model at 1, 7, and 14 days after injury. 32 C57BL/6J mice were separated into 4 groups (control, 1, 7, and 14 days) of 8, with 4 males and 4 females in each. Mice were exposed to sonication-induced trauma as described previously (by Tao et al) and optic nerves were harvested at 1, 7, or 14 days following injury [4]. Mitochondria were isolated from homogenized optic nerves and lipids were extracted. Extracted mitochondrial lipids were analysed with a Q-Exactive Orbitrap Liquid Chromatography-Mass Spectrometer (LC MS-MS). Further analysis of raw data was conducted with LipidSearch 4.1.3 and Metaboanalyst 4.0. This data is publicly available at the Metabolomics Workbench, http://www.metabolomicsworkbench.org (Project ID: PR000905).

Inter Individual Variation and Factors Regulating the Formation of Phosphatidylethanol

BACKGROUND

Alcohol use disorders are a major but often unrecognized health problem. Alcohol markers can therefore be of great value for diagnosis, follow-up, and treatment evaluation. Phosphatidylethanol in blood (B-PEth) is an alcohol biomarker with higher clinical sensitivity and specificity than commonly used alcohol markers but has shown a considerable interindividual variation in relation to reported consumption.

METHODS

An in vitro system was used to investigate factors, which may affect the formation rate of PEth or which may give rise to interindividual variation in the rate of formation. In this system, isolated erythrocytes from 31 individuals were incubated in the presence of various concentrations of ethanol (EtOH). The concentration of PEth and phosphatidylcholine (PC), the parent molecule of PEth, was determined by chromatographic methods.

RESULTS

Time, EtOH, and PC concentration were major factors determining the amount of PEth formed. The interindividual variation in PEth formation rate, calculated at an EtOH concentration of 50 mmol/l, showed a coefficient of variation (CV) from 23 to 31% for the different PEth forms studied (PEth 16:0/18:2, total PEth and PEth 16:0/18:1). The concentration of PC was found to be an important determinant of this variation. The formation rate for PEth 16:0/18:2 was somewhat higher than for PEth 16:0/18:1. The formation of PEth 16:0/18:1 but not PEth 16:0/18:2 showed a positive correlation to the concentration of PEth at baseline (endogenous PEth). Calculation of enzyme kinetics for the reaction resulting in the formation of PEth 16:0/18:1 or PEth 16:0/18:2 showed an apparent K_m (Michaelis constant) of approximately 160 to 170 mmol/l.

CONCLUSIONS

Interindividual variation in the formation rate of PEth appears to be a significant but relatively modest source of variation in the relation between B-PEth and reported consumption. Correction for interindividual variation in PC concentrations might substantially reduce the interindividual variability in PEth formation and consequently in B-PEth.

Oxygen Availability during Growth Modulates the Phytochemical Profile and the Chemo-Protective Properties of Spinach Juice

Fruits and vegetables are a good source of potentially biologically active compounds. Their regular consumption in the human diet can help reduce the risk of developing chronic diseases such as cardiovascular diseases and cancer. Plants produce additional chemical substances when subject to abiotic stress or infected by microorganisms. The phytochemical profile of spinach leaves (Spinacia oleracea L.), which is a vegetable with widely recognized health-promoting activity, has been affected by applying root hypoxic and re-oxygenation stress during plant growth. Leaf juice at different sampling times has been subject to liquid chromatography mass spectrometry (LC-MSn) analysis and tested on the human colorectal adenocarcinoma cell line HT29 by using the Comet assay. The cells were previously treated with H₂O₂ to simulate the presence of an oxidative stress (as in colon cancer condition) and the leaf juice application resulted in a significant antioxidant and protective in vitro effect. The duration of the hypoxic/re-oxygenation stress imposed on the plant reflects the antioxidant leaf juice content. After hypoxic stress (24 h) and reoxygenation (2 h), we show a decrease (50%) of the relative abundance of the principal identified antioxidant molecules but a higher antioxidant activity of the spinach juice on HT29 cells (20%). Data shows a complex relation between plant growing conditions and the modulation of secondary metabolites content in leaf juice that results in different chemo-protective activities in colon cancer cells.

Disulfide Bond Characterization of Endogenous IgG3 Monoclonal Antibodies Using LC-MS: An Investigation of IgG3 Disulfide-mediated Isoforms

The use of monoclonal antibodies (mAbs) for the manufacture of innovator and biosimilar biotherapeutics has increased tremendously in recent years. From a structural perspective, mAbs have high disulfide bond content, and the correct disulfide connectivity is required for proper folding and to maintain their biological activity. Therefore, disulfide linkage mapping is an important component of mAB characterization for ensuring drug safety and efficacy. The native disulfide linkage patterns of all four subclasses of IgG antibodies have been well established since the late 1960s. Among these IgG subtypes, disulfide mediated isoforms have been identified for IgG2 and IgG4, and to a lesser extent in IgG1, which is the most studied IgG subclass. However, no studies have been carried out so far to investigate whether different IgG3 isoforms exist due to alternative disulfide connectivity. In an effort to investigate the presence of disulfide-mediated isoforms in IgG3, we employed a bottom-up mass spectrometry approach to accurately determine the disulfide bond linkages in endogenous human IgG3 monoclonal antibody and our results show that no such alternative disulfide bonds exist. While many antibody-based drugs are developed around IgG1, IgG3 represents a new, and in some cases, more desirable drug candidate. Our data represent the first demonstration that alternative disulfide bond arrangements are not present in endogenous IgG3; and therefore, they should not be present in recombinant forms used as antibody-based therapeutics.