ABSTRACT:Intestinal cell lines are used as in vitro models for pharmacological and toxicological studies. However, a general report of the gene expression spectrum of proteins that are involved in the metabolism and the disposition of xenobiotics in these in vitro systems is not currently available. To fill this information gap, we systematically characterized the expression profile of 377 genes encoding xenobiotic-metabolizing enzymes, transporters, and nuclear receptors and transcription factors in intestinal mucosa (ileum, ascending colon, transverse colon, descending colon, and rectum) from five healthy subjects and in five commonly used intestinal cell lines (Caco-2, C2BBe1, HT29, T84, and FHC).

Substituted cathinones are synthetic analogs of cathinone that can be considered as derivatives of phenethylamines with a beta-keto group on the side chain. They appeared in the recreational drug market in the mid-2000s and now represent a large class of new popular drugs of abuse. Initially considered as legal highs, their legal status is variable by country and is rapidly changing, with government institutions encouraging their control. Some cathinones (such as diethylpropion or pyrovalerone) have been used in a medical setting and bupropion is actually indicated for smoking cessation. Substituted cathinones are widely available from internet websites, retail shops, and street dealers. They can be sold under chemical, evocative or generic names, making their identification difficult. Fortunately, analytical methods have been developed in recent years to solve this problem. Available as powders, substituted cathinones are self-administered by snorting, oral injestion, or intravenous injection. They act as central nervous system stimulants by causing the release of catecholamines (dopamine, noradrenaline, and serotonin) and blocking their reuptake in the central and peripheral nervous system. They may also decrease dopamine and serotonin transporter function as nonselective substrates or potent blockers and may inhibit monoamine oxidase effects. Nevertheless, considerable differences have been found in the potencies of the different substituted cathinones in vitro. Desired effects reported by users include increased energy, empathy, and improved libido. Cardiovascular (tachycardia, hypertension) and psychiatric/neurological signs/symptoms (agitation, seizures, paranoia, and hallucinations) are the most common adverse effects reported. Severe toxicity signs compatible with excessive serotonin activity, such as hyperthermia, metabolic acidosis, and prolonged rhabdomyolysis, have also been observed. Reinforcing potential observed in animals predicts a high potential for addiction and abuse in users. In case of overdose, no specific antidote exists and no curative treatment has been approved by health authorities. Therefore, management of acute toxic effects is mainly extrapolated from experience with cocaine/amphetamines.

This study constitutes the first report of a functional genetic polymorphism that could affect Rac1 expression and thus modulate the risk of adverse drug reaction in patients under thiopurine treatment. A larger scale (case-control) study should enable us to confirm or cancel these preliminary results.