Investigations of the genotoxic properties of two synthetic cathinones (3-MMC, 4-MEC) which are used as psychoactive drugs

Genotoxicity Evaluation of The Novel Psychoactive Substance MTTA

MTTA, also known as mephtetramine, is a stimulant novel psychoactive substance characterized by a simil-cathinonic structure. To date, little has been studied on its pharmaco-toxicological profile, and its genotoxic potential has never been assessed. In order to fill this gap, the aim of the present work was to evaluate its genotoxicity on TK6 cells in terms of its ability to induce structural and numerical chromosomal aberrations by means of a cytofluorimetric protocol of the "In Vitro Mammalian Cell Micronucleus (MN) test". To consider the in vitro effects of both the parental compound and the related metabolites, TK6 cells were treated with MTTA in the absence or presence of an exogenous metabolic activation system (S9 mix) for a short-term time (3 h) followed by a recovery period (23 h). No statistically significant increase in the MNi frequency was detected. Specifically, in the presence of S9 mix, only a slight increasing trend was observable at all tested concentrations, whereas, without S9 mix, at 75 µM, almost a doubling of the negative control was reached. For the purposes of comprehensive evaluation, a long-term treatment (26 h) was also included. In this case, a statistically significant enhancement in the MNi frequency was observed at 50 µM.

Evaluation of Cytotoxic and Mutagenic Effects of the Synthetic Cathinones Mexedrone, α-PVP and α-PHP

Mexedrone, α-PVP and α-PHP are synthetic cathinones. They can be considered amphetamine-like substances with a stimulating effect. Actually, studies showing their impact on DNA are totally absent. Therefore, in order to fill this gap, aim of the present work was to evaluate their mutagenicity on TK6 cells. On the basis of cytotoxicity and cytostasis results, we selected the concentrations (35–100 µM) to be used in the further analysis. We used the micronucleus (MN) as indicator of genetic damage and analyzed the MNi frequency fold increase by flow cytometry. Mexedrone demonstrated its mutagenic potential contrary to the other two compounds; we then proceeded by repeating the analyzes in the presence of extrinsic metabolic activation in order to check if it was possible to totally exclude the mutagenic capacity for α-PVP and α-PHP. The results demonstrated instead the mutagenicity of their metabolites. We then evaluated reactive oxygen species (ROS) induction as a possible mechanism at the basis of the highlighted effects but the results did not show a statistically significant increase in ROS levels for any of the tested substances. Anyway, our outcomes emphasize the importance of mutagenicity evaluation for a complete assessment of the risk associated with synthetic cathinones exposure.

p-synephrine induces transcriptional changes via the cAMP/PKA pathway but not cytotoxicity or mutagenicity in human gastrointestinal cells

p-Synephrine (SN) is an alkaloid added to thermogenic formulations for weight loss that is predominantly absorbed in the human gastrointestinal tract (GI). As the adverse effects of SN on GI cells remain unclear, the aim of present study was to examine whether SN affected cell viability, cell cycle kinetics, genomic stability, redox status, and expression of cAMP/PKA pathway genes related to metabolism/energy homeostasis in stomach mucosa (MNP01) and colon adenocarcinoma (Caco-2) human cells. p-Synephrine at 25-5000 μM was not cytotoxic to both cell lines. At 2-200 μM, SN increased the formation of reactive oxygen species (ROS) but also enhanced levels of antioxidant defense molecules glutathione (GSH) and catalase (CAT) activity, which may account for the absence of cytotoxicity/mutagenicity in both cell lines. SN induced expression of the cAMP/PKA pathway genes ADCY3 and MAPK1 in MNP01 cells and MAPK1, GNAS, PRKACA, and PRKAR2A in Caco-2 cells, as well as modulated the transcription of genes related to cell proliferation (JUN; AKT1) and inflammation (RELA; TNF) in both cell lines. Therefore, the improved antioxidant state mitigated pro-oxidative effects attributed to SN. Evidence indicates that SN does not appear to exhibit adverse potential but modulated the cAMP/PKA pathway in human GI cell lines.

Effect of temperature on 3,4-Methylenedioxypyrovalerone (MDPV)-induced metabolome disruption in primary mouse hepatic cells

3,4-Methylenedioxypyrovalerone (MDPV) is one of the most popular cathinone derivatives worldwide and has recently been associated with several intoxications and deaths, in which, similarly to amphetamines, hyperthermia appears to play a prominent role. However, there remains a huge information gap underlying the mechanisms associated with its hepatotoxicity, namely under hyperthermic conditions. Here, we use a sensitive untargeted metabolomic approach based on gas chromatography-mass spectrometry (GC-MS) to investigate the effect of subtoxic and toxic concentrations of MDPV on the metabolic profile of primary mouse hepatocytes (PMH), under normothermic and hyperthermic conditions. For this purpose, hepatocytes were exposed to increasing concentrations of MDPV (LC₀₁, LC₁₀ and LC₃₀) for 24 h, at 37 °C or 40.5 °C, and alterations on both intracellular metabolome and extracellular volatilome were evaluated. Multivariate analysis showed a clear separation between MDPV exposed cells and control cells in normothermic conditions, even at subtoxic concentrations (LC₀₁ and LC₁₀). In normothermia, there was a significant dysregulation of pathways associated with ascorbate metabolism, tricarboxylic acid (TCA) cycle and pyruvate metabolism. These metabolic changes were significantly increased at 40.5 °C, and several other pathways appear to be affected with the evolution of toxicity caused by MDPV under hyperthermic conditions, namely aspartate and glutamate metabolism, phenylalanine and tyrosine biosynthesis, aminoacyl-tRNA biosynthesis, butanoate metabolism, among others. Overall, our findings provide novel insights into the mechanism of hepatotoxicity triggered by MDPV and highlight the higher risks that may occur under hyperthermic conditions.