The Fanconi syndrome is a common side effect of the chemotherapeutic agent ifosfamide. Current evidences suggest that chloroacetaldehyde (CAA), one of the main metabolites of ifosfamide activation, contributes to its nephrotoxicity. However, the pathophysiology of CAA-induced Fanconi syndrome is not fully understood. The present work examined the adverse effects of CAA on precision-cut rat renal cortical slices, which allowed studying the toxic effect of CAA on proximal endocytosis. We demonstrated that clinically relevant concentrations of CAA (< or =200 microM) are able to inhibit the uptake of horseradish peroxidase, a marker of proximal tubular cell endocytosis in renal tubular proximal cells. CAA > or =75 microM has adverse effects, both on viability parameters and on energy metabolism, as shown by the great decrease in total glutathione and ATP levels. In addition, the V-ATPase, which plays a crucial role in intracellular vesicle trafficking, was inhibited by 100 microM of CAA. By contrast, the slight decrease in Na-K-ATPase activity observed for CAA> or = 125 microM (maximum inhibition: 33%) could not totally explain the inhibition of the reabsorption processes. In conclusion, the addition of the two main adverse effects of CAA (decrease in ATP levels and inhibition of the V-ATPase) could explain the inhibition of endocytosis and the Fanconi syndrome observed during ifosfamide treatments.

Chloroacetaldehyde (CAA) is the putative metabolite responsible for ifosfamide-induced nephrotoxicity. Whereas evidence suggests that sodium 2-mercaptoethanesulfonate (mesna) and amifostine protect renal cells against CAA toxicity in vitro, their efficacy in clinical studies is controversial. To better understand the discrepancy between in vivo and in vitro results, we combined the in vivo intraperitoneal administration of either saline or mesna (100 mg/kg) or amifostine (200 mg/kg) in rats and the in vitro study of CAA toxicity to both proximal tubules and precision-cut renal cortical slices. The measured renal cortical concentrations of mesna and amifostine were 0.6+/-0.1 micromol/g and 1.2+/-0.2 micromol/g, respectively; these drugs did not cause renal toxicity. Despite this, none of the adverse effects of 0.5 mM CAA was prevented by the previous in vivo administration of mesna or amifostine. Toxicity of 0.5 mM CAA to rat proximal tubules was shown by the fall of cellular adenosine triphosphate (ATP), total glutathione and coenzyme A + acetyl-coenzyme A levels and by the altered metabolic viability of renal cells. Long-term exposure of cortical slices to CAA concentrations > or =30 microM caused severe cell toxicity (i.e. decrease in cellular ATP, total glutathione, and coenzyme A + acetyl-coenzyme A levels), which was not prevented by the in vivo administration of mesna or amifostine.