Mixtures of 3,4-methylenedioxymethamphetamine ( ecstasy ) and its major human metabolites act additively to induce significant toxicity to liver cells when combined at low, non-cytotoxic concentrations: Combination of MDMA and metabolites

Recreational MDMA doses do not elicit hepatotoxicity in HepG2 spheroids under normo- and hyperthermia

MDMA (3,4-methylenedioxymethamphetamine), an entactogen with empathogenic and prosocial effects, is widely used in music festivals and other festive settings. High MDMA doses have been associated with drug-induced liver injury and cases of hyperthermia. Although the latter condition is thought to increase MDMA hepatotoxicity, this correlation remains poorly explored for recreational MDMA doses. On the other hand, the fact that MDMA acts to extinguish fear and to reconsolidate memory could be explored as an adjunct to psychotherapy during treatment of neuropsychiatric disorders such as post-traumatic stress disorder. In this context, assessing MDMA toxicity is relevant, and tridimensional cell culture has emerged as an alternative to animal models in toxicity assessment. Herein, we have used HepG2 spheroids to evaluate MDMA-induced hepatotoxicity at recreational doses, under normo- or hyperthermia. The MTT reduction assay did not evidence significantly reduced cell viability. Moreover, MDMA did not increase reactive oxygen species production, deplete the mitochondrial membrane potential, arrest the cell cycle, or induce apoptotic cell death. These findings support further pre-clinical investigation of MDMA safety from the perspective of both harm reduction and therapy given that non-abusive recreational and therapeutic doses overlap.

Toxicity of pesticides widely applied on soybean cultivation: Synergistic effects of fipronil, glyphosate and imidacloprid in HepG2 cells

The transgenic soy monoculture demands supplementation with pesticides. The aim of this study was to evaluate the individual and mixture effects of fipronil, glyphosate and imidacloprid in human HepG2 cells. Cytotoxicity was evaluated after 48-h incubations through MTT reduction and neutral red uptake assays. Free radicals production, mitochondrial membrane potential, DNA damage, and release of liver enzymes were also evaluated. Data obtained for individual agents were used to compute the additivity expectations for two mixtures of definite composition (one equipotent mixture, based in the EC₅₀ values achieved in the MTT assay; the other one based in the acceptable daily intake of each pesticide), using the models of concentration addition and independent action. The EC₅₀ values for fipronil, glyphosate and imidacloprid were 37.59, 41.13, and 663.66 mg/L, respectively. The mixtures of pesticides elicited significant synergistic effects (p < 0.05), which were greater than the expected by both addictive predictions. Decreased in mitochondrial membrane potential and increased in the transaminases enzymatic activities were observed. As they occur simultaneously, interactions between pesticides, even at non-effective single levels, can reverberate in significant deleterious effects, justifying the need for a more realistic approach in safety evaluations to better predict the effects to human health.

From street to lab: in vitro hepatotoxicity of buphedrone, butylone and 3,4-DMMC

Synthetic cathinones are among the most popular new psychoactive substances, being abused for their stimulant properties, which are similar to those of amphetamine and 3,4-methylenedioxymethamphetamine (MDMA). Considering that the liver is a likely target for cathinones-induced toxicity, and for their metabolic activation/detoxification, we aimed to determine the hepatotoxicity of three commonly abused synthetic cathinones: butylone, α-methylamino-butyrophenone (buphedrone) and 3,4-dimethylmethcathinone (3,4-DMMC). We characterized their cytotoxic profile in primary rat hepatocytes (PRH) and in the HepaRG and HepG2 cell lines. PRH was the most sensitive cell model, showing the lowest EC₅₀ values for all three substances (0.158 mM for 3,4-DMMC; 1.21 mM for butylone; 1.57 mM for buphedrone). Co-exposure of PRH to the synthetic cathinones and CYP450 inhibitors (selective and non-selective) proved that hepatic metabolism reduced the toxicity of buphedrone but increased that of butylone and 3,4-DMMC. All compounds were able to increase oxidative stress, disrupting mitochondrial homeostasis and inducing apoptotic and necrotic features, while also increasing the occurrence of acidic vesicular organelles in PRH, compatible with autophagic activation. In conclusion, butylone, buphedrone and 3,4-DMMC have hepatotoxic potential, and their toxicity lies in the interference with a number of homeostatic processes, while being influenced by their metabolic fate.

Pharmacokinetic and Pharmacodynamic Aspects of Peyote and Mescaline: Clinical and Forensic Repercussions

BACKGROUND

Mescaline (3,4,5-trimethoxyphenethylamine), mainly found in the Peyote cactus (Lophophora williamsii), is one of the oldest known hallucinogenic agents that influence human and animal behavior, but its psychoactive mechanisms remain poorly understood.

OBJECTIVES

This article aims to fully review pharmacokinetics and pharmacodynamics of mescaline, focusing on the in vivo and in vitro metabolic profile of the drug and its implications for the variability of response.

METHODS

Mescaline pharmacokinetic and pharmacodynamic aspects were searched in books and in PubMed (U.S. National Library of Medicine) without a limiting period. Biological effects of other compounds found in peyote were also reviewed.

RESULTS

Although its illicit administration is less common, in comparison with cocaine and Cannabis, it has been extensively described in adolescents and young adults, and licit consumption often occurs in religious and therapeutic rituals practiced by the Native American Church. Its pharmacodynamic mechanisms of action are primarily attributed to the interaction with the serotonergic 5-HT2A-C receptors, and therefore clinical effects are similar to those elicited by other psychoactive substances, such as lysergic acid diethylamide (LSD) and psilocybin, which include euphoria, hallucinations, depersonalization and psychoses. Moreover, as a phenethylamine derivative, signs and symptoms are consistent with a sympathomimetic effect. Mescaline is mainly metabolized into trimethoxyphenylacetic acid by oxidative deamination but several minor metabolites with possible clinical and forensic repercussions have also been reported.

CONCLUSION

Most reports concerning mescaline were presented in a complete absence of exposure confirmation, since toxicological analysis is not widely available. Addiction and dependence are practically absent and it is clear that most intoxications appear to be mild and are unlikely to produce lifethreatening symptoms, which favors the contemporary interest in the therapeutic potential of the drugs of the class.

Emerging club drugs: 5-(2-aminopropyl)benzofuran (5-APB) is more toxic than its isomer 6-(2-aminopropyl)benzofuran (6-APB) in hepatocyte cellular models

New phenylethylamine derivatives are among the most commonly abused new psychoactive substances. They are synthesized and marketed in lieu of classical amphetaminic stimulants, with no previous safety testing. Our study aimed to determine the in vitro hepatotoxicity of two benzofurans [6-(2-aminopropyl)benzofuran (6-APB) and 5-(2-aminopropyl)benzofuran (5-APB)] that have been misused as 'legal highs'. Cellular viability was assessed through the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay, following 24-h drug exposure of human hepatoma HepaRG cells (EC₅₀ 2.62 mM 5-APB; 6.02 mM 6-APB), HepG2 cells (EC₅₀ 3.79 mM 5-APB; 8.18 mM 6-APB) and primary rat hepatocytes (EC₅₀ 964 μM 5-APB; 1.94 mM 6-APB). Co-incubation of primary hepatocytes, the most sensitive in vitro model, with CYP450 inhibitors revealed a role of metabolism, in particular by CYP3A4, in the toxic effects of both benzofurans. Also, 6-APB and 5-APB concentration-dependently enhanced oxidative stress (significantly increased reactive species and oxidized glutathione, and decreased reduced glutathione levels) and unsettled mitochondrial homeostasis, with disruption of mitochondrial membrane potential and decline of intracellular ATP. Evaluation of cell death mechanisms showed increased caspase-8, -9, and -3 activation, and nuclear morphological changes consistent with apoptosis; at concentrations higher than 2 mM, however, necrosis prevailed. Concentration-dependent formation of acidic vesicular organelles typical of autophagy was also observed for both drugs. Overall, 5-APB displayed higher hepatotoxicity than its 6-isomer. Our findings provide new insights into the potential hepatotoxicity of these so-called 'safe drugs' and highlight the putative risks associated with their use as psychostimulants.

The new psychoactive substance 3-methylmethcathinone (3-MMC or metaphedrone) induces oxidative stress, apoptosis, and autophagy in primary rat hepatocytes at human-relevant concentrations

3-Methylmethcathinone (3-MMC or metaphedrone) has become one of the most popular recreational drugs worldwide after the ban of mephedrone, and was recently deemed responsible for several intoxications and deaths. This study aimed at assessing the hepatotoxicity of 3-MMC. For this purpose, Wistar rat hepatocytes were isolated by collagenase perfusion, cultured and exposed for 24 h at a concentration range varying from 31 nM to 10 mM 3-MMC. The modulatory effects of cytochrome P450 (CYP) inhibitors on 3-MMC hepatotoxicity were evaluated. 3-MMC-induced toxicity was perceived at the lysosome at lower concentrations (NOEC 312.5 µM), compared to mitochondria (NOEC 379.5 µM) and cytoplasmic membrane (NOEC 1.04 mM). Inhibition of CYP2D6 and CYP2E1 diminished 3-MMC cytotoxicity, yet for CYP2E1 inhibition this effect was only observed for concentrations up to 1.3 mM. A significant concentration-dependent increase of intracellular reactive species was observed from 10 μM 3-MMC on; a concentration-dependent decrease in antioxidant glutathione defences was also observed. At 10 μM, caspase-3, caspase-8, and caspase-9 activities were significantly elevated, corroborating the activation of both intrinsic and extrinsic apoptosis pathways. Nuclear morphology and formation of cytoplasmic acidic vacuoles suggest prevalence of necrosis and autophagy at concentrations higher than 10 μM. No significant alterations were observed in the mitochondrial membrane potential, but intracellular ATP significantly decreased at 100 μM. Our data point to a role of metabolism in the hepatotoxicity of 3-MMC, which seems to be triggered both by autophagic and apoptotic/necrotic mechanisms. This work is the first approach to better understand 3-MMC toxicology.

Non-alcoholic fatty liver disease and obesity: the role of the gut bacteria

Non-alcoholic fatty-liver disease (NAFLD) is now considered one of the leading causes of liver disease worldwide and is associated with metabolic syndrome and obesity. There are several factors contributing to the disease state. Recent research suggests that the intestinal microbiota (IM) and bacterial products may play a role through several mechanisms which include increased energy uptake, intestinal permeability and chronic inflammation. In addition to diet and exercise, treatment options targeting the IM are being investigated and include the use of pre-, pro- and synbiotics as well as the possibility of fecal microbial transfers. This literature review explores the relationship between NAFLD and the IM as well as highlight new IM treatment options that may become available in the near future.

A Conserved Role for Serotonergic Neurotransmission in Mediating Social Behavior in Octopus

Human and octopus lineages are separated by over 500 million years of evolution [1, 2] and show divergent anatomical patterns of brain organization [3, 4]. Despite these differences, growing evidence suggests that ancient neurotransmitter systems are shared across vertebrate and invertebrate species and in many cases enable overlapping functions [5]. Sociality is widespread across the animal kingdom, with numerous examples in both invertebrate (e.g., bees, ants, termites, and shrimps) and vertebrate (e.g., fishes, birds, rodents, and primates) lineages [6]. Serotonin is an evolutionarily ancient molecule [7] that has been implicated in regulating both invertebrate [8] and vertebrate [9] social behaviors, raising the possibility that this neurotransmitter's prosocial functions may be conserved across evolution. Members of the order Octopoda are predominantly asocial and solitary [10]. Although at this time it is unknown whether serotonergic signaling systems are functionally conserved in octopuses, ethological studies indicate that agonistic behaviors are suspended during mating [11-13], suggesting that neural mechanisms subserving social behaviors exist in octopuses but are suppressed outside the reproductive period. Here we provide evidence that, as in humans, the phenethylamine (+/-)-3,4-methylendioxymethamphetamine (MDMA) enhances acute prosocial behaviors in Octopus bimaculoides. This finding is paralleled by the evolutionary conservation of the serotonin transporter (SERT, encoded by the Slc6A4 gene) binding site of MDMA in the O. bimaculoides genome. Taken together, these data provide evidence that the neural mechanisms subserving social behaviors exist in O. bimaculoides and indicate that the role of serotonergic neurotransmission in regulating social behaviors is evolutionarily conserved.

Ethanol addictively enhances the in vitro cardiotoxicity of cocaine through oxidative damage, energetic deregulation, and apoptosis

Cocaine (COC) is frequently consumed in polydrug abuse settings, and ethanol (EtOH) is the most prominent co-abused substance. Clinical data and experimental evidence suggest that the co-administration of COC with EtOH can be more cardiotoxic than EtOH or COC alone, but information on the molecular pathways involved is scarce. Since these data are crucial to potentiate the identification of therapeutic targets to treat intoxications, we sought to (i) elucidate the type of interaction that occurs between both substances, and (ii) assess the mechanisms implicated in the cardiotoxic effects elicited by COC combined with EtOH. For this purpose, H9c2 cardiomyocytes were exposed to COC (104 µM-6.5 mM) and EtOH (977 µM-4 M), individually or combined at a molar ratio based on blood concentrations of intoxicated abusers (COC 1: EtOH 9; 206 µM-110 mM). After 24 h, cell metabolic viability was recorded by the MTT assay and mixture toxicity expectations were calculated using the independent action (IA) and concentration addition (CA) models. EtOH (EC₅₀ 305.26 mM) proved to act additively with COC (EC₅₀ 2.60 mM) to significantly increase the drug in vitro cardiotoxicity, even when both substances were combined at individually non-cytotoxic concentrations. Experimental mixture testing (EC₅₀ 19.18 ± 3.36 mM) demonstrated that the cardiotoxicity was fairly similar to that predicted by IA (EC₅₀ 22.95 mM) and CA (EC₅₀ 21.75 mM), supporting additivity. Concentration-dependent increases of intracellular ROS/RNS and GSSG, depletion of GSH and ATP, along with mitochondrial hyperpolarization and activation of intrinsic, extrinsic, and common apoptosis pathways were observed both for single and combined exposures. In general, the mixture exhibited a toxicological profile that mechanistically did not deviate from the single drugs, suggesting that interventions such as antioxidant administration might aid in the clinical treatment of this type of polydrug intoxication. In a clinical perspective, the observed additive mixture effect may reflect the increased hazards at which users of this combination are exposed to in recreational settings.

Is online information on ecstasy tablet content safe?

BACKGROUND AND AIMS

In recent years, the prevalence of ecstasy use has increased in most European countries. Users can acquire information on ecstasy tablet composition through the internet. This study compares online information from two websites, Pillreports and Partyflock, to the validated Dutch Drugs Information and Monitoring System (DIMS) database, and aims to measure its accuracy and potential danger or value.

DESIGN, SETTING, PARTICIPANTS

The drug-related information posted on Pillreports.net and Partyflock.nl between 1 January 2014 and 31 December 2015 was investigated for accuracy and several information characteristics such as picture inclusion and dose range inclusion. In total, 471 informatory statements on ecstasy tablet content were analysed relative to the Dutch ecstasy market.

MEASUREMENTS

Informatory statements on the content of specific ecstasy tablets were scored as 'too high' or 'too low' if their concentrations deviated > 10 mg from the entries in the DIMS database within a 12-week time-frame, and scored as 'dangerous' if their concentration was > 40 mg too low. Unreported substances were scored as 'dangerous' if listed as an illegal or dangerous substance in the DIMS database and if present in relevant quantities. Also scored were the report characteristics 'picture inclusion', 'spread inclusion' and 'website source', which were tested for their association with report safety/danger.

FINDINGS

On average, reports on ecstasy tablets from Pillreports and Partyflock show concentrations which are 10.6 mg too high [95% confidence interval (CI) = 6.7-14.4]. Qualitatively, 39.7% of the reports scored as 'too high' (95% CI = 35.2-44.4), 17.6% scored as 'too low' (95% CI = 14.0-21.2) and 15.5% had 'unreported substances' (95% CI = 12.3-18.9), resulting overall in 15.3% of the reports being scored as 'dangerous' (95% CI = 11.9-18.5). The report characteristic 'spread inclusion' associated inversely with report danger [Exp(b) = 0.511, 95% CI = 0.307-0.850, P = 0.01].

CONCLUSION

Information from the popular Pillreports and Partyflock websites tends to overestimate 3,4-methylenedioxymethamphetamine (MDMA) concentrations in ecstasy tablets. In addition, 15.3% of the reports omit the relevant concentration spread, fail to report additional illegal or dangerous substances contained in the tablets or underestimate MDMA concentration by > 40 mg.

In vitro hepatotoxicity of 'Legal X': the combination of 1-benzylpiperazine (BZP) and 1-(m-trifluoromethylphenyl)piperazine (TFMPP) triggers oxidative stress, mitochondrial impairment and apoptosis

N-Benzylpiperazine (BZP) and 1-(3-trifluoromethylphenyl)piperazine (TFMPP) are two synthetic phenylpiperazine analogues that have been frequently commercialized in combination as an alternative to ecstasy ('Legal X'). Despite reports of several clinical complications following the use of these drugs in association, few studies have been conducted so far to elucidate their combined toxicity. The present study was aimed at clarifying the cytotoxic effects of mixtures of BZP and TFMPP in vitro. Human-derived HepaRG cells and primary rat hepatocytes were exposed to the drugs, individually or combined at different mixture ratios, and cytotoxicity was assessed by the MTT assay. Mixture additivity expectations were calculated by the independent action and the concentration addition (CA) models and compared with the experimental outcomes. To delineate the mechanisms underlying the elicited effects, a range of stress endpoints was evaluated, including oxidative stress, energetic imbalance, and metabolic interactions. It was observed that primary rat hepatocytes are more sensitive than HepaRG cells to the toxicity of BZP (EC₅₀ 2.20 and 6.60 mM, respectively) and TFMPP (EC₅₀ 0.14 and 0.45 mM, respectively). For all BZP-TFMPP combinations tested, CA was the most appropriate model to predict the mixture effects. TFMPP proved to act additively with BZP to produce significant hepatotoxicity (p < 0.01). Remarkably, substantial mixture effects were observed even when each drug was present at concentrations that were harmless individually. In primary hepatocytes, a small deviation from additivity (antagonism) was observed toward the upper range of the concentration-response curve. GC/MS data suggest that a metabolic interaction may be at a play, as the mixture favors the metabolism of both substances, to a significant extent in the case of BZP (p < 0.05). Also, our results demonstrate the influence of oxidative stress and energetic imbalance on these effects (increase in RNS and ROS production, decrease in intracellular GSH/GSSG, ATP depletion and mitochondrial Δψm disruption). The present work clearly demonstrates that potentially harmful interactions among BZP and TFMPP are expected when these drugs are taken concomitantly.

Editor's Highlight: Characterization of Hepatotoxicity Mechanisms Triggered by Designer Cathinone Drugs (β-Keto Amphetamines)

The use of cathinone designer drugs in recreational settings has been associated with severe toxic effects, including liver damage. The precise mechanisms by which cathinones induce hepatotoxicity and whether they act by common pathways remain to be elucidated. Herein, we assessed the toxicity of the cathinones methylone, pentedrone, 3,4-methylenedioxypyrovalerone (MDPV) and 4-methylethcathinone (4-MEC) in primary rat hepatocytes (PRH) and HepaRG cells, and compared with that of 3,4-methylenedioxymethamphetamine (MDMA). MDPV and pentedrone were significantly more toxic than MDMA, while methylone was the least cytotoxic compound. Importantly, PRH revealed to be the most sensitive experimental model and was thus used to explore the mechanisms underlying the observed toxicity. All drugs elicited the formation of reactive oxygen and nitrogen species (ROS and RNS), but more markedly for methylone, pentedrone and 4-MEC. GSH depletion was also a common effect at the highest concentration tested, whereas only MDPV and pentedrone caused a significant decrease in ATP levels. The antioxidants ascorbic acid or N-acetyl-L-cysteine partially attenuated the observed cell death. All cathinones triggered significant caspase activation and apoptosis, which was partially reversed by the caspase inhibitor Ac-LETD-CHO. In conclusion, the present data shows that (1) cathinones induce in vitro hepatotoxic effects that vary in magnitude among the different analogues, (2) oxidative stress and mitochondrial dysfunction play a role in cathinones-induced hepatic injury, and (3) apoptosis appears to be an important pathway of cell death elicited by these novel drugs.

Hepatotoxicity of piperazine designer drugs: Comparison of different in vitro models

Piperazine derived drugs emerged on the drug market in the last decade. The aim of this study was to investigate in vitro the potential hepatotoxicity of the designer drugs N-benzylpiperazine (BZP), 1-(3-trifluoromethylphenyl)piperazine (TFMPP), 1-(4-methoxyphenyl)piperazine (MeOPP) and 1-(3,4-methylenedioxybenzyl)piperazine (MDBP) in two human hepatic cell lines (HepaRG and HepG2) and in primary rat hepatocytes. Cell death was evaluated by the MTT assay, after 24 h-incubations. Among the tested drugs, TFMPP was the most cytotoxic. HepaRG cells and primary hepatocytes revealed to be the most and the least resistant cellular models, respectively. To ascertain whether the CYP450 metabolism could explain their higher susceptibility, primary hepatocytes were co-incubated with the piperazines and the CYP450 inhibitors metyrapone and quinidine, showing that CYP450-mediated metabolism contributes to the detoxification of these drugs. Additionally, the intracellular contents of reactive species, ATP, reduced (GSH) and oxidized (GSSG) glutathione, changes in mitochondrial membrane potential (Δψm) and caspase-3 activation were further evaluated in primary cells. Overall, an increase in reactive species formation, followed by intracellular GSH and ATP depletion, loss of Δψm and caspase-3 activation was observed for all piperazines, in a concentration-dependent manner. In conclusion, piperazine designer drugs produce hepatic detrimental effects that can vary in magnitude among the different analogues.