A new approach on methamphetamine-induced hepatotoxicity: involvement of mitochondrial dysfunction.

1. Methamphetamine (METH) is a highly addictive stimulant that is among the most widely abused illicit drugs. Clinical evidence has shown that the liver is a target of METH toxicity. The exact cellular and molecular mechanisms involved in METH-induced hepatotoxicity have not yet been completely understood. 2. In this study, the cellular pathways involved in METH liver toxicity were investigated in freshly isolated rat hepatocytes. METH cytotoxicity was associated with reactive oxygen species (ROS) formation, lipid peroxidation and rapid glutathione (GSH) depletion which is a third marker of cellular oxidative stress. Our results showed that the hepatocyte mitochondrial membrane potential (ΔΨm) was rapidly decreased by METH, which was prevented by antioxidants and ROS scavenger, suggesting that mitochondrial membrane damage was a consequence of ROS formation. Incubation of hepatocytes with METH also caused release of cytochrome c from mitochondria into the cytosol before cell lysis ensued. 3. Our findings showed that cytotoxic action of METH is mediated by oxidative stress and subsequent changes in mitochondrial membrane conformation and cytochrome c release into the cytosol which causes mitochondrial collapse of ΔΨm.

Determination of impurities in illicit methamphetamine samples seized in Iran.

In this study fifty samples of crystalline methamphetamine obtained from antinarcotics police of Iran seized during the year 2010 were analyzed. In order to determine the chemical characteristics of these samples, anion test, Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS) were carried out on the samples. All of the samples containing methamphetamine tested positive for chloride anion. The range of methamphetamine hydrochloride content in these samples was 33-95%. One sample out of 50 contained no methamphetamine. The fact that 1,2-dimethyl-3-phenylaziridine was the most frequently found impurity in the analyzed samples, indicates that most of the methamphetamine samples seized in Iran have been synthesized from pseudoephedrine as starting material.

Profiling of ecstasy tablets seized in iran.

In this study 50 samples of ecstasy tablets seized in Iran during the period of 2007 through 2008 were examined and their physical characteristics (appearance, marking, scored/not scored, color, weight, diameter, thickness) were determined. In order to determine the chemical characteristics of these tablets, color tests (Marquis test, Simon's test, Chen's test and Gallic acid test), Thin Layer Chromatography (TLC), anion test, residual solvents, Gas Chromatography-Mass Spectrometry (GC-MS) and Liquid Chromatography-Mass Spectrometry (LC-MS) were carried out on the tablets. The range of tablets weight was 96-308 mg and the range of 3,4-methylenedioxymethamphetamine (MDMA) hydrochloride content in these tablets was 60-180 mg. No good correlation was found between the tablets weight and their MDMA contents. All of the tablets containing MDMA had this compound in hydrochloride form. Ketamine, phenmetrazine and ephedrine (or pseudoephedrine) were found in some of the tablets along with MDMA. No MDMA was found in 20% of the tablets. Some of these tablets contained compounds such as caffeine or tramadol as their active ingredient.

Involvement of mitochondrial/lysosomal toxic cross-talk in ecstasy induced liver toxicity under hyperthermic condition.

The initial objectives of this study were to evaluate the extent of 3, 4-methylenedioxymethamphetamine (MDMA) induced loss of cell viability (cytotoxicity), induction of reactive oxygen species formation and damage to sub-cellular organelles (e.g. mitochondria/lysosomes) in freshly isolated rat hepatocytes under normothermic conditions (37 degrees C) and to compare the results with the effects obtained under hyperthermic conditions (41 degrees C). MDMA induced cytotoxicity, reactive oxygen species formation, mitochondrial membrane potential decline and lysosomal membrane leakiness in isolated rat hepatocytes at 37 degrees C. A rise in incubation temperature from 37 degrees C to 41 degrees C had an additive/synergic effect on the oxidative stress markers. We observed variations in mitochondrial membrane potential and lysosomal membrane stability that are significantly (P<0.05) higher than those under normothermic conditions. Antioxidants, reactive oxygen species scavengers, lysosomal inactivators, mitochondrial permeability transition (MPT) pore sealing agents, NADPH P450 reductase inhibitor, and inhibitors of reduced CYP2E1 and CYP2D6 prevented all MDMA induced hepatocyte oxidative stress cytotoxicity markers. It is therefore suggested that metabolic reductive activation of MDMA by reduced cytochrome P450s and glutathione could lead to generation of some biological reactive intermediates which could activate reactive oxygen species generation and cause mitochondrial and lysosomal oxidative stress membrane damages. We finally concluded that hyperthermia could potentiate MDMA induced liver toxicity probably through a mitochondrial/lysosomal toxic cross-talk in freshly isolated rat hepatocytes.