A combined toxicokinetic and metabolic approach to investigate deschloro-N-ethylketamine exposure in a multidrug user

The use of new psychoactive substances derived from ketamine is rarely reported in France. A chronic GHB, 3-MMC, and methoxetamine consumer presented a loss of consciousness in a chemsex context and was referred to the intensive care unit with a rapid and favorable outcome. To investigate the chemicals responsible for the intoxication, a comprehensive analysis was conducted on the ten plasma samples collected over a 29.5-hour period, urine obtained upon admission, a 2-cm hair strand sample, and a seized crystal. These analyses were performed using liquid chromatography hyphenated to high resolution tandem mass spectrometry operating in targeted and untargeted modes. Additionally, analyses using gas chromatography coupled to mass spectrometry and nuclear magnetic resonance were conducted to probe the composition of the seized crystal. The molecular network-based approach was employed for data processing in non-targeted analyses. It allowed to confirm a multidrug exposure encompassing GHB, methyl-(aminopropyl)benzofuran (MAPB), (aminopropyl)benzofuran (APB), methylmethcathinone, chloromethcathinone, and a new psychoactive substance belonging to the arylcyclohexylamine family namely deschloro-N-ethyl-ketamine (O-PCE). Molecular network analysis facilitated the annotation of 27 O-PCE metabolites, including phase II compounds not previously reported. Plasma kinetics of O-PCE allowed the estimation of the elimination half-life of ∼5 hours. Kinetics of O-PCE metabolites was additionally characterized, possibly useful as surrogate biomarkers of consumption. We also observed marked alterations in lipid metabolism related to poly consumption of drugs. In conclusion, this case report provides a comprehensive analysis of exposure to O-PCE in a multidrug user including kinetic and metabolism data in human.

Pro-active drug-facilitated crimes (DFC): a study in the Department of Forensic Medicine of Paris, France

INTRODUCTION

Proactive drug facilitated crime (DFC) is the administration of psychoactive substances (PAS) for criminal purposes without the victim's knowledge or by force. In Paris, France, patients who report suspected proactive DFC to the police are examined at the Department of Forensic Medicine (DFM) of the Hôtel-Dieu Hospital. Preventively blood and urine samples are collected but not systematically analyzed by the judicial authority. We aimed to assess the proportion of probable proactive DFC in patients examined at the Hôtel-Dieu DFM following a police report for suspected proactive DFC.

METHOD

Blood and urine samples were collected from 100 patients. Toxicological analyses were performed by the toxicology laboratory of the Lariboisière Hospital. The results were correlated with the clinical data collected at the initial and follow-up consultations.

RESULTS

At least one PAS was detected in 86% of the cases (voluntary or involuntary intake). After correlation with clinical data, 32% of the cases were classified as probable proactive DFC. In these cases, 49% of the substances identified were illicit substances (amphetamines, MDMA, etc.); 16% were benzodiazepines and related substances; 16% were antihistamines and sedatives; 14% were opioids; and 5% were antidepressants and anti-epileptics. In 90% of the cases, patients reported a voluntary ethanol consumption in the hours prior to the suspected proactive DFC.

CONCLUSION

Toxicological analyses revealed a high proportion of both probable proactive DFC and probable opportunistic DFC. Our results indicate the need to perform systematical toxicological analysis in cases of suspected DFC.

Corneal neuroepithelial compartmentalized microfluidic chip model for evaluation of toxicity-induced dry eye

Part of the lacrimal functional unit, the cornea protects the ocular surface from numerous environmental aggressions and xenobiotics. Toxicological evaluation of compounds remains a challenge due to complex interactions between corneal nerve endings and epithelial cells. To this day, models do not integrate the physiological specificity of corneal nerve endings and are insufficient for the detection of low toxic effects essential to anticipate Toxicity-Induced Dry Eye (TIDE). Using high-content imaging tool, we here characterize toxicity-induced cellular alterations using primary cultures of mouse trigeminal sensory neurons and corneal epithelial cells in a compartmentalized microfluidic chip. We validate this model through the analysis of benzalkonium chloride (BAC) toxicity, a well-known preservative in eyedrops, after a single (6h) or repeated (twice a day for 15 min over 5 days) topical 5.10-4% BAC applications on the corneal epithelial cells and nerve terminals. In combination with high-content image analysis, this advanced microfluidic protocol reveal specific and tiny changes in the epithelial cells and axonal network as well as in trigeminal cells, not directly exposed to BAC, with ATF3/6 stress markers and phospho-p44/42 cell activation marker. Altogether, this corneal neuroepithelial chip enables the evaluation of toxic effects of ocular xenobiotics, distinguishing the impact on corneal sensory innervation and epithelial cells. The combination of compartmentalized co-culture/high-content imaging/multiparameter analysis opens the way for the systematic analysis of toxicants but also neuroprotective compounds.

Plasma lipidomic analysis to investigate putative biomarkers of P-glycoprotein activity in healthy volunteers

P-glycoprotein (P-gp) is an efflux transporter involved in the bioavailability of many drugs currently on the market. P-gp is responsible for several drug-drug interactions encountered in clinical practice leading to iatrogenic hospital admissions, especially in polypharmacy situations. ABCB1 genotyping only reflects an indirect estimate of P-gp activity. Therefore, it would be useful to identify endogenous biomarkers to determine the P-gp phenotype to predict in vivo activity prior to the initiation of treatment and to assess the effects of drugs on P-gp activity. The objective of this study was to assess changes in plasma lipidome composition among healthy volunteers selected on the basis of their ABCB1 genotype and who received clarithromycin, a known inhibitor of P-gp. Untargeted lipidomic analysis based on liquid chromatography-tandem mass spectrometry was performed before and after clarithromycin administration. Our results revealed changes in plasma levels of some ceramides (Cers) {Cer(d18:1/22:0), Cer(d18:1/22:1), and Cer(d18:1/20:0) by ~38% (p < 0.0001), 13% (p < 0.0001), and 13% (p < 0.0001), respectively} and phosphatidylcholines (PCs) {PC(17:0/14:1), PC(16:0/18:3), and PC(14:0/18:3) by ~24% (p < 0.001), 10% (p < 0.001), and 23.6% (p < 0.001)} associated with both ABCB1 genotype and clarithromycin intake. Through the examination of plasma lipids, our results highlight the relevance of untargeted lipidomics for studying in vivo P-gp activity and, more generally, to safely phenotyping transporters.

New Trend in Toxicological Screening Using Volumetric Absorptive Microsampling (VAMS) and High-Resolution Mass Spectrometry (HR/MS) Combination

In toxicology, screenings are routinely performed using chromatographic methods coupled to detection systems such as high-resolution mass spectrometry (HR/MS). The increase in specificity and sensitivity of HRMS is responsible for the development of methods for alternative samples such as Volumetric Adsorptive Micro-Sampling. Whole blood overloaded with 90 drugs was sampled with 20 µL Mitra^TM to optimize the pre-analytical step as well as to determine the identification limits of drugs. Elution of chemicals was carried out in a solvent mixture through agitation and sonication. After dissolution, 10 μL was injected into the chromatographic system coupled to the Orbitrap^TM HR/MS. Compounds were confirmed against the laboratory library. The clinical feasibility was assessed in fifteen poisoned patients using the simultaneous sampling of plasma, whole blood and Mitra^TM. The optimized extraction procedure allowed us to confirm 87 compounds out of the 90 present in the spiked whole blood. Cannabis derivatives were not detected. For 82.2% of the investigated drugs, the identification limits were below 12.5 ng·mL^-1, with the extraction yields ranging from 80.6 to 108.7%. Regarding the patients' analysis, 98% of the compounds in plasma were detected in Mitra^TM compared to whole blood, with a satisfying concordance (R² = 0.827). Our novel screening approach opens new insights into different toxicologic fields appropriate for pediatrics, forensics or to perform mass screening.

Human plasma ricinine quantification by LC-HRMS after micro-solid-phase elution

A rapid, sensitive and specific method for ricinine identification and quantification in plasma has been developed by LC-HRMS. Deuterated ricinine was used as the internal standard. From 100 μL of plasma, ricinine was extracted using micro-solid-phase elution, which allows a reduced extraction time, by eliminating the evaporation step. Eluate is directly injected into the LC-HRMS system. Chromatographic separation was performed using a reverse-phase C₁₈ column with a 4.5 min gradient elution. The method was validated according to European Medicines Agency guidelines. Linearity was verified between 0.25 and 500.0 ng/mL; the maximum precision calculated was 19.9% for the lower limit of quantitation and 9.6% for quality control, and accuracy was within ± 5.6% of the nominal concentrations. Selectivity, carryover, matrix effect and stability were also verified according to European Medicines Agency guidelines. The method allows the rapid and reliable identification of ricin-exposed victims in case of terrorist attacks or poisonings: three intoxication cases are reported.

Identification of new Omega-3 very long chain poly-unsaturated fatty acids in meibomian gland secretions

Three new very long chain polyunsaturated fatty acids (VLC PUFA) belonging to the omega-3 family have been identified in meibum samples collected by Schirmer strips. These VLC PUFA, namely FA (32:3), FA (34:3) and FA (36:3), were detected in O-acyl-ω-hydroxy fatty acids using a molecular network approach, and as free fatty acids. Identification was supported by retention time prediction model, exact mass determination and isotopic patterns. Double bond location was determined using cross metathesis reaction associated to tandem mass spectrometry. In meibum, synthesis of these VLC PUFA is likely to be mediated by elongation of very long chain fatty acids 4 enzyme. The biological role of these newly VLC PUFA and their occurrence in other tissues and biological fluids remains to be elucidated.

Molecular Network-Based Identification of Tramadol Metabolites in a Fatal Tramadol Poisoning

Identification of xenobiotics and their phase I/II metabolites in poisoned patients remains challenging. Systematic approaches using bioinformatic tools are needed to detect all compounds as exhaustively as possible. Here, we aimed to assess an analytical workflow using liquid chromatography coupled to high-resolution mass spectrometry with data processing based on a molecular network to identify tramadol metabolites in urine and plasma in poisoned patients. The generated molecular network from liquid chromatography coupled to high-resolution tandem mass spectrometry data acquired in both positive and negative ion modes allowed for the identification of 25 tramadol metabolites in urine and plasma, including four methylated metabolites that have not been previously reported in humans or in vitro models. While positive ion mode is reliable for generating a network of tramadol metabolites displaying a dimethylamino radical in their structure, negative ion mode was useful to cluster phase II metabolites. In conclusion, the combined use of molecular networks in positive and negative ion modes is a suitable and robust tool to identify a broad range of metabolites in poisoned patients, as shown in a fatal tramadol-poisoned patient.

Bisphenol A Impairs Lipid Remodeling Accompanying Cell Differentiation in the Oligodendroglial Cell Line Oli-Neu

In the central nervous system, the process of myelination involves oligodendrocytes that wrap myelin around axons. Myelin sheaths are mainly composed of lipids and ensure efficient conduction of action potentials. Oligodendrocyte differentiation is an essential preliminary step to myelination which, in turn, is a key event of neurodevelopment. Bisphenol A (BPA), a ubiquitous endocrine disruptor, is suspected to disrupt this developmental process and may, thus, contribute to several neurodevelopmental disorders. In this study, we assessed the effect of BPA on oligodendrocyte differentiation through a comprehensive analysis of cell lipidome by UHPLC-HRMS. For this purpose, we exposed the oligodendroglial cell line Oli-neu to several BPA concentrations for 72 h of proliferation and another 72 h of differentiation. In unexposed cells, significant changes occurred in lipid distribution during Oli-neu differentiation, including an increase in characteristic myelin lipids, sulfatides, and ethanolamine plasmalogens, and a marked remodeling of phospholipid subclasses and fatty acid contents. Moreover, BPA induced a decrease in sulfatide and phosphatidylinositol plasmalogen contents and modified monounsaturated/polyunsaturated fatty acid relative contents in phospholipids. These effects counteracted the lipid remodeling accompanying differentiation and were confirmed by gene expression changes. Altogether, our results suggest that BPA disrupts lipid remodeling accompanying early oligodendrocyte differentiation.

Deepening of lipidome annotation by associating cross-metathesis reaction with mass spectrometry: application to an in vitro model of corneal toxicity

The in-depth knowledge of lipid biological functions needs a comprehensive structural annotation including a method to locate fatty acid unsaturations, which remains a thorny problem. For this purpose, we have associated Grubbs' cross-metathesis reaction and liquid chromatography hyphenated to tandem mass spectrometry to locate double bond positions in lipid species. The pretreatment of lipid-containing samples by Grubbs' catalyst and an appropriate alkene generates substituted lipids through cross-metathesis reaction under mild, chemoselective, and reproducible conditions. A systematic LC-MS/MS analysis of the reaction mixture allows locating unambiguously the double bonds in fatty acid side chains of phospholipids, glycerolipids, and sphingolipids. This method has been successfully applied at a nanomole scale to commercial standard mixtures consisting of 10 lipid subclasses as well as in lipid extracts of human corneal epithelial (HCE) cell line allowing to pinpoint double bond of more than 90 species. This method has also been useful to investigate the lipid homeostasis alteration in an in vitro model of corneal toxicity, i.e., HCE cells incubated with benzalkonium chloride. The association of cross-metathesis and tandem mass spectrometry appears suitable to locate double bond positions in lipids involved in relevant biological processes.

In Vitro Chemopreventive Potential of Phlorotannins-Rich Extract from Brown Algae by Inhibition of Benzo[a]pyrene-Induced P2X7 Activation and Toxic Effects

Phlorotannins are polyphenols occurring exclusively in some species of brown algae, known for numerous biological activities, e.g., antioxidant, antiproliferative, antidiabetic, and antiallergic properties. Their effects on the response of human lung cells to benzo[a]pyrene (B[a]P) has not been characterized. Our objective was to in vitro evaluate the effects of a phlorotannin-rich extract obtained from the brown algae Ascophyllum nodosum and Fucus vesiculosus on B[a]P cytotoxic effects. The A549 cell line was incubated with B[a]P for 48 and 72 h in the presence or absence of the brown algae extract. Cytochrome P450 activity, activation of P2X7 receptor, F-actin disorganization, and loss of E-cadherin expression were assessed using microplate cytometry and fluorescence microscopy. Relative to control, incubation with the brown algae extract was associated with lower B[a]P-induced CYP1 activity, lower P2X7 receptor activation, and lower reactive oxygen species production. The brown algae extract inhibited the alterations of F-actin arrangement and the downregulation of E-cadherin expression. We identified a phlorotannins-rich extract that could be deeper investigated as a cancer chemopreventive agent to block B[a]P-mediated carcinogenesis.

Lipidomic analysis of human corneal epithelial cells exposed to ocular irritants highlights the role of phospholipid and sphingolipid metabolisms in detergent toxicity mechanisms

Detergent chemicals, widely used in household products, in pharmaceutical, medical, cosmetic and industrial fields, have been linked to side effects and involved in several eye diseases. On the ocular surface, detergents can interfere with the corneal epithelium, the most superficial layer of the cornea, representing a line of defence against external aggression. Despite its major role in numerous biological functions, there is still little data regarding disruption of lipid homeostasis induced by ocular irritants. To this purpose, a lipidomic analysis using UPLC-HRMS/MS-ESI ± was performed on human corneal epithelial (HCE) cells incubated with three widely known ocular irritants: benzalkonium chloride (BAK), sodium lauryl sulfate (SLS) and Triton X-100 (TXT). We found that these ocular irritants lead to a profound modification of the HCE cell lipidome. Indeed, the cell content of ceramide species increased widely while plasmalogens containing polyunsaturated fatty acid species, especially docosahexaenoic acids, decreased. Furthermore, these irritants upregulated the activity of phospholipase A₂. The present study demonstrates that BAK, SLS and TXT induced disruption of the cell lipid homeostasis, highlighting that lipids mediate inflammatory and cell death processes induced by detergents in the cornea. Lipidomics may thus be regarded as a valuable tool to investigate new markers of corneal damage.

Lipid Annotation by Combination of UHPLC-HRMS (MS), Molecular Networking, and Retention Time Prediction: Application to a Lipidomic Study of In Vitro Models of Dry Eye Disease

Annotation of lipids in untargeted lipidomic analysis remains challenging and a systematic approach needs to be developed to organize important datasets with the help of bioinformatic tools. For this purpose, we combined tandem mass spectrometry-based molecular networking with retention time (t_R) prediction to annotate phospholipid and sphingolipid species. Sixty-five standard compounds were used to establish the fragmentation rules of each lipid class studied and to define the parameters governing their chromatographic behavior. Molecular networks (MNs) were generated through the GNPS platform using a lipid standards mixture and applied to lipidomic study of an in vitro model of dry eye disease, i.e., human corneal epithelial (HCE) cells exposed to hyperosmolarity (HO). These MNs led to the annotation of more than 150 unique phospholipid and sphingolipid species in the HCE cells. This annotation was reinforced by comparing theoretical to experimental t_R values. This lipidomic study highlighted changes in 54 lipids following HO exposure of corneal cells, some of them being involved in inflammatory responses. The MN approach coupled to t_R prediction thus appears as a suitable and robust tool for the discovery of lipids involved in relevant biological processes.