Role of metabolites in MDMA (ecstasy)-induced nephrotoxicity: An in vitro study using rat and human renal proximal tubular cells

Márcia Carvalho, Gabrielle Hawksworth, Nuno Milhazes, Fernanda Borges, Terrence J. Monks, Eduarda Fernandes, Félix Carvalho, Maria Bastos

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

The metabolism of 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) has recently been implicated in the mechanisms underlying ecstasy-induced neurotoxicity and hepatotoxicity. However, its potential role in ecstasy-induced kidney toxicity has yet to be investigated. Thus, primary cultures of rat and human renal proximal tubular cells (PTCs) were used to investigate the cytotoxicity induced by MDMA and its metabolites methylenedioxyamphetamine (MDA), α-methyldopamine (α-MeDA), and the glutathione (GSH) conjugates 5-(glutathion-S-yl)-α-MeDA and 2,5-bis(glutathion-S-yl)-α-MeDA. Cell viability was evaluated using the mitochondrial MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. MDMA and MDA were not found to be toxic to either rat or human PTCs at any concentration tested (100-800 μM). In contrast, 800 μM α-MeDA caused 60% and 40% cell death in rat and human PTCs, respectively. Conjugation of α-MeDA with GSH resulted in the formation of even more potent nephrotoxicants. Thus, exposure of rat and human PTC monolayers to 400 μM 5-(glutathion-S-yl)-α-MeDA caused approximately 80% and 70% cell death, respectively. 5-(Glutathion-S-yl)-α-MeDA (400 μM) was more toxic than 2,5-bis(glutathion-S-yl)-α-MeDA to rat renal PTCs but equally potent in human renal PTCs. Pre-incubation of rat PTCs with either acivicin, an inhibitor of γ-glutamyl transpeptidase (γ-GT), or bestatin, an inhibitor of aminopeptidase M, resulted in increased toxicity of 5-(glutathion-S-yl)-α-MeDA but had no effect on 2,5-bis(glutathion-S-yl)-α-MeDA-mediated cytotoxicity. The present data provide evidence that metabolism is required for the expression of MDMA-induced renal toxicity in vitro. In addition, metabolism of 5-(glutathion-S-yl)-α-MeDA by γ-GT and aminopeptidase M to the corresponding cystein-S-yl-glycine and/or cystein-S-yl conjugates is likely to be associated with detoxication of this compound. Thus, it appears that toxicity induced by thioether metabolites of ecstasy at the apical membrane of renal proximal tubular cells is the result of extracellular events, presumably redox cycling.

Original languageEnglish (US)
Pages (from-to)581-588
Number of pages8
JournalArchives of Toxicology
Volume76
Issue number10
DOIs
StatePublished - Oct 16 2002

Keywords

  • Human
  • MDMA
  • Metabolites, Glutathione conjugate
  • Rat
  • Renal proximal tubular cells

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis

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