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.

The chorioallantoic membrane: A novel approach to extrapolate data from a well-established method

The chorioallantoic membrane (CAM) of the chicken embryo is a highly vascularized extra‐embryonic structure that has been widely used as an in vivo model for the evaluation of angiogenesis. This study was designed to optimize data extrapolation from the most exploited experimental protocol to improve its efficiency and the reliability of the obtainable results. In our study, we followed the most common procedure for CAM assay, employing retinoic acid and vascular endothelial growth factor as standards. CAMs were photographed at t₀, t₂₄, and t₄₈; then, the main parameters of the predefined vascular network/area were evaluated. Subsequently, their variations in each CAM were calculated comparing them within the same CAM over the course of the whole treatment (t₂₄ and t₄₈), also comparing the treated CAMs respect to the untreated ones. Thus, we provide a novel approach aimed at extrapolating data from CAM assay that allows to (i) have a greater reliability and richness of data; (ii) better estimate the potential pro‐ and anti‐angiogenic activity of new candidate drugs; (iii) save both eggs and time for the experiments.

The chorioallantoic membrane (CAM) is a structure exploited for the in vivo evaluation of angiogenesis. This study was designed to optimize data extrapolation from a well‐established experimental protocol to improve its efficiency and reliability of the obtainable results. Thus, we provide a novel approach aimed at extrapolating data from CAM assay that allows to (i) have a greater reliability and richness of data; (ii) better estimate the pro‐ and anti‐angiogenic activity of new drugs; (iii) save both eggs and time for the experiments.

How to Study the Metabolism of New Psychoactive Substances for the Purpose of Toxicological Screenings-A Follow-Up Study Comparing Pooled Human Liver S9, HepaRG Cells, and Zebrafish Larvae

The new psychoactive substances (NPS) market continues to be very dynamic. A large number of compounds belonging to diverse chemical groups continue to emerge. This makes their detection in biological samples challenging for clinical and forensic toxicologists. Knowledge of the metabolic fate of NPS is crucial for developing comprehensive screening procedures. As human studies are not feasible due to ethical concerns, the current study aimed to compare the NPS' metabolic pattern in incubations with pooled human liver S9 fraction (pHLS9), human liver HepaRG cells, and zebrafish larvae. The latter model was recently shown to be a promising preclinical surrogate for human hepatic metabolism of a synthetic cannabinoid. However, studies concerning other NPS classes are still missing and therefore an amphetamine-based N-methoxybenzyl (NBOMe) compound, a synthetic cathinone, a pyrrolidinophenone analog, a lysergamide, as well as another synthetic cannabinoid were included in the current study. Liquid chromatography coupled to Orbitrap-based high-resolution tandem mass spectrometry was used to analyze metabolic data. Zebrafish larvae were found to produce the highest number of phase I but also phase II metabolites (79 metabolites in total), followed by HepaRG cells (66 metabolites). Incubations with pHLS9 produced the least metabolites (57 metabolites). Furthermore, the involvement of monooxygenases and esterases in the metabolic phase I transformations of 4F-MDMB-BINACA was elucidated using single-enzyme incubations. Several cytochrome P450 (CYP) isozymes were shown to contribute, and CYP3A5 was involved in all CYP-catalyzed reactions, while amide and ester hydrolysis were catalyzed by the human carboxylesterase (hCES) isoforms hCES1b and/or hCES1c. Finally, metabolites were compared to those present in human biosamples if data were available. Overall, the metabolic patterns in HepaRG cells provided the worst overlap with that in human biosamples. Zebrafish larvae experiments agreed best with data found in human plasma and urine analysis. The current study underlines the potential of zebrafish larvae as a tool for elucidating the toxicokinetics of NPS in the future.

In Vitro Toxicological Screening of Stable and Senescing Cultures of Aphanizomenon, Planktothrix, and Raphidiopsis

Toxicity of cyanobacteria is the subject of ongoing research, and a number of toxic metabolites have been described, their biosynthesis pathways have been elucidated, and the mechanism of their action has been established. However, several knowledge gaps still exist, e.g., some strains produce hitherto unknown toxic compounds, while the exact dynamics of exerted toxicity during cyanobacterial growth still requires further exploration. Therefore, the present study investigated the toxicity of extracts of nine freshwater strains of Aphanizomenon gracile, an Aphanizomenon sp. strain isolated from the Baltic Sea, a freshwater strain of Planktothrix agardhii, and two strains of Raphidiopsis raciborskii obtained from 25- and 70-day-old cultures. An in vitro experimental model based on Cyprinus carpio hepatocytes (oxidative stress markers, DNA fragmentation, and serine/threonine protein activity) and brain homogenate (cholinesterase activity) was employed. The studied extracts demonstrated toxicity to fish cells, and in general, all examined extracts altered at least one or more of considered parameters, indicating that they possess, to some degree, toxic potency. Although the time from which the extracts were obtained had a significant importance for the response of fish cells, we observed strong variability between the different strains and species. In some strains, extracts that originated from 25-day-old cultures triggered more harmful effects on fish cells compared to those obtained from 70-day-old cultures, whereas in other strains, we observed the opposite effect or a lack of a significant change. Our study revealed that there was no clear or common pattern regarding the degree of cyanobacterial bloom toxicity at a given stage of development. This means that young cyanobacterial blooms that are just forming can pose an equally toxic threat to aquatic vertebrates and ecosystem functioning as those that are stable or old with a tendency to collapse. This might be largely due to a high variability of strains in the bloom.

[Accreditation of the toxicological screening: recommendations of the SFBC-SFTA group]

Toxicological screening is a specific approach to analytical toxicology that uses analytical tools such as GC-MS, LC-UV (diode array) or LC-MS. Toxicological screening allows the detection and simultaneous identification of a large number of compounds. The results may be based on the use of one or more techniques. As part of the accreditation process for medical biology examinations according to standard NF EN ISO 15189, the group from SFTA and SFBC recommends an approach to accredit toxicological screening. Indeed, the complexity of the accreditation of this analysis comes in particular from the high number of compounds that can be detected. Validation parameters are discussed in the specific context of toxicological screening by considering two distinct approaches: the simple identification of compounds, or the identification and estimation of a range of concentration related to clinical outcomes.

Embryonic stem cells: An alternative approach to developmental toxicity testing

Stem cells in the body have a unique ability to renew themselves and give rise to more specialized cell types having functional commitments. Under specified growth conditions, these cell types remain unspecialized but can be triggered to become specific cell type of the body such as heart, nerve, or skin cells. This ability of embryonic stem cells for directed differentiation makes it a prominent candidate as a screening tool in revealing safer and better drugs. In addition, genetic variations and birth defects caused by mutations and teratogens affecting early human development could also be studied on this basis. Moreover, replacement of animal testing is needed because it involves ethical, legal, and cost issues. Thus, there is a strong requirement for validated and reliable, if achievable, human stem cell-based developmental assays for pharmacological and toxicological screening.

Recreational use of mephedrone (4-methylmethcathinone, 4-MMC) with associated sympathomimetic toxicity

INTRODUCTION

Cathinone is a pharmacologically active alkaloid that can be extracted from the leaves of the khat plant (Catha edulis). There are synthetic derivatives of cathinone entering the recreational drug market, including mephedrone (4-methylmethcathinone, 4-MMC). There are discrepancies in the legal status of both the khat plant and its extracted alkaloids between the UK and the USA.

CASE REPORT

A 22-year-old man purchased 4 g of mephedrone powder over the Internet from a chemical supplier based in China. He initially ingested 200 mg of the mephedrone orally, with no perceived clinical effects, and thereafter injected the remaining 3.8 g intramuscularly into his thighs. Shortly after the injection, he developed palpitations, "blurred tunnel vision," chest pressure, and sweating and felt generally unwell; he presented to hospital with continuing features of sympathomimetic toxicity. His symptoms settled over the next 4 h after a single dose of oral lorazepam. Qualitative analysis of the urine and serum sample was undertaken using gas chromatography with mass spectrometric (GC/MS) detection, both positive for the presence of 4-methylmethcathinone. Quantitative analysis of the serum sample was undertaken by liquid chromatography with tandem mass spectrometric detection; the estimated mephedrone concentration was 0.15 mg/l. Routine toxicological analysis of the serum and urine specimens using a broad GC/MS toxicology screen did not detect any other drugs or alcohol.

DISCUSSION

This is the first case of isolated 4-MMC toxicity, with confirmatory analytical findings. It is important that clinical toxicologists and emergency physicians work together to ensure a better understanding of the toxicity of novel/emerging drugs such as 4-MMC.

Delayed onset of seizures and toxicity associated with recreational use of Bromo-dragonFLY

INTRODUCTION

Many countries have specific legislation, such as the Controlled Substances Act (1970) in the United States and the Misuse of Drugs Act (1971) in the United Kingdom to control recreational drugs. There is a growing market and supply of "novel" recreational drugs, which include the misuse of pharmaceutical compounds and research chemicals. These are often not covered under current legislation, despite the fact that they often have both similar chemical structures and/or clinical effects to controlled recreational drugs.

CASE REPORT

A male patient presented to an emergency department with delayed onset of severe agitation, hallucinations, and tonic-clonic seizures following the use of Bromo-dragonFLY and an unknown white powder. He settled following IV benzodiazepines and supportive care, and was discharged with no evidence of long-term sequelae. Analysis of the white powder by gas chromatography/mass spectrometry (GC/MS), ultraviolet/visible spectrophotometry (UV/VIS) and thin layer chromatography (TLC) showed the presence of Bromo-dragonFLY (1-(8-bromobenzo[1,2-b;4,5-b']difuran-4-yl)-2-aminopropane); serum analysis by GC/MS and liquid chromatography with tandem mass spectrometry (LC/MS/MS) confirmed that a combination of Bromo-dragonFLY (0.95 ng/mL), ketamine (20 ng/mL) and cannabis had been used by the patient. No other recreational drugs were detected in an extensive toxicological screen of serum and urine samples.

DISCUSSION

This is the first confirmed case to be reported of toxicity with delayed onset of severe agitation, hallucinations and tonic-clonic seizures associated with recreational use of Bromo-dragonFLY (1-(8-bromobenzo[1,2-b;4,5-b']difuran-4-yl)-2-aminopropane) in combination with ketamine and cannabis. In our view, this case provides further support for the need for a systematic approach to toxicological screening of patients with recreational drug toxicity, to identify emerging drugs and provide evidence for legislative authorities to assist in revising the legal status of emerging recreational drugs.