Renal toxicity of the antitumor drug N2-methyl-9-hydroxyellipticinium acetate in the Wistar rat

Time course study of lipid peroxidation induced by N2-methyl-9-hydroxyellipticinium acetate or celiptium in rat renal cortex

Celiptium is an ellipticine derivative with renal toxic side effects. It has recently been characterized as a lipid overload in proximal tubular cells where loss of total phospholipids (in particular phosphatidylethanolamine) and of polyunsaturated fatty acids are linked to the accumulation of unsaturated free fatty acids and aldehydes. A time course study of celiptium-induced peroxidative damage showed that a single dose of 40 mg/kg of celiptium induced no change in total or individual phospholipids of rat renal cortex. On the other hand, free fatty acids and thiobarbituric acid reactive substances increased as early as 1 hr after celiptium injection. 4-Hydroxynonenal (4-HNE) also increased whereas polyunsaturated fatty acids levels decreased at 6 and 24 hr. After 24 hr no change was detected in microsomal phospholipids. In contrast, the brush-border membranes showed alterations such as decrease in total phospholipids and polyunsaturated fatty acids levels accompanied by increase in aldehydes. It appears that peroxidative damage occurs in brush-border membranes of celiptium-treated rat kidneys with preferential losses of phosphatidylethanolamine (PE, 30%) and phosphatidylcholine (PC, 14%).

Nephrotoxicity of an ellipticine derivative (N2-methyl-9-hydroxyellipticinium acetate) in rat: a defect of urinary concentrating ability

The antitumor drug celiptium (N2-methyl-9-hydroxyellipticinium) is an ellipticine derivative effective in experimental tumors and in man. The major side effect is nephrotoxicity. The impairment of renal function is studied in rats following a single i.v. dose of 20 mg/kg celiptium and a long-term study (day 2 to day 60). A loss of body weight is noted in celiptium-treated animals between day 4 and day 15, and recovery occurs between day 15 and day 60. Histologic study shows cortical lesions characterized by focal necrosis of proximal tubules without any glomerular, interstitial, and vascular alterations on day 8. It is to be noted that any medullary lesions were not shown. A polyuria and a decreased creatinine clearance are reported on day 8. We were interested in a special study of this polyuria. For this study, rats were water deprived between day 6 and day 8 following celiptium administration. The decrease of urinary osmolality is not recovered after dehydration and exogenous vasopressin derivative (dD AVP) does not correct the renal concentration defect. AVP plasma levels increase after dehydration. These results suggest a pitressino-resistant urinary concentrating inability in celiptium-treated rats.

Evidence for 4-hydroxyalkenals in rat renal cortex peroxidized by N2-methyl-9-hydroxyellipticinium acetate or Celiptium

The antitumor drug celiptium is an ellipticine derivative whose nephrotoxic pathogenesis implicates a lipid peroxidation process. It has been shown that hydrophobic lipid deposits overload the proximal tubular cells. Histochemistry with Holczinger's technique has demonstrated that these deposits are free fatty acids. In this study, the fatty acid analysis of phospholipids and neutral lipids was performed in rat renal cortex 4 and 8 days following a single i.v. dose of 20 mg/kg celiptium and showed: (1) a loss of polyunsaturated fatty acids within total phospholipids and a loss of phosphatidylethanolamine with a preferential decrease of arachidonic (20:4) and docosahexaenoic (22:6) acids; (2) an increase of free fatty acid levels with an increase in oleic (18:1) and linoleic (18:2) acids; (3) an increase of thiobarbituric acid-reactive substances or aldehydes. The analysis of these aldehydes showed significant amounts of 4-hydroxyalkenals, mainly the presence of 4-hydroxynonenal on day 4 and of a hydroxyaldehyde with a chromatographic behavior very similar to 4-HNE on day 8. We conclude that celiptium induced a preferential decrease of phosphatidylethanolamine linked to the formation of unsaturated free fatty acids and of 4-hydroxyalkenals. The toxic side-effects of these breakdown products produced in the proximal tubular cell are discussed in light of the lipid peroxidation process involved in the renal toxicity of celiptium.

Celiptium-induced nephrotoxicity and lipid peroxidation in rat renal cortex

The antitumor drug celiptium, or N2-methyl-9-hydroxyellipticinium (NMHE), is an ellipticine derivative used in the treatment of breast cancer. Celiptium-induced dose-dependent renal toxicity in rats is characterized by tubular necrosis, tubulo-interstitial lesions and lipid overload in proximal tubular cells. Since biooxidative activation of celiptium occurs in kidney via highly electrophilic intermediates, we studied the effects of celiptium on rat renal cortex lipids in the context of lipid peroxidation damage. Female Wistar rats were injected with a single i.v. dose of 20 mg/kg celiptium and were killed on day 2, 4 or 8. Histochemical analysis of kidney sections detected Oil Red O (ORO)-positive deposits, whereas the same sections studied using Holczinger's copper rubeanic acid method showed free fatty acid (FFA) granules in renal tubular cells of celiptium-treated rats. Electron microscopy revealed large fatty droplets in proximal tubular cells. As creatinine clearance decreased on days 4 and 8, celiptium induced a significant increase in renal cortex FFA levels (6-fold increase over pretreatment values on day 8), whereas total glycerides increased 1.5 times. A 15% decrease in total phospholipids (PL) and a 50% decline in the mass of phosphatidylethanolamine (PE) were detected by lipid phosphorus assay. A 1.2-fold decrease in the unsaturation index of total PL was noted, with a significant decline in arachidonic acid (20:4). A 15% decrease in arachidonic content was observed in the fatty acid composition of PE. Analysis of the fatty acid composition of neutral lipids showed changes only in the FFA class. A great proportion of oleic (18:1) and linoleic (18:2) acids was found. Iodometric titration and thiobarbituric acid (TBA) reactivity detected respectively significant amounts of lipid hydroperoxides and TBA-reactive material in renal cortex lipid extracts on days 2, 4 and 8. The lipid-peroxidation process appeared to be involved in the pathogenesis of celiptium nephrotoxicity.