Phospholipidosis in rats treated with amiodarone: serum biochemistry and whole genome micro-array analysis supporting the lipid traffic jam hypothesis and the subsequent rise of the biomarker BMP

Toxicol Pathol. 2012 Apr;40(3):491-503. doi: 10.1177/0192623311432290. Epub 2012 Jan 30.

Abstract

To provide mechanistic insight in the induction of phospholipidosis and the appearance of the proposed biomarker di-docosahexaenoyl (C22:6)-bis(monoacylglycerol) phosphate (BMP), rats were treated with 150 mg/kg amiodarone for 12 consecutive days and analyzed at three different time points (day 4, 9, and 12). Biochemical analysis of the serum revealed a significant increase in cholesterol and phospholipids at the three time points. Bio-analysis on the serum and urine detected a time-dependent increase in BMP, as high as 10-fold compared to vehicle-treated animals on day 12. Paralleling these increases, micro-array analysis on the liver of treated rats identified cholesterol biosynthesis and glycerophospholipid metabolism as highly modulated pathways. This modulation indicates that during phospholipidosis-induction interactions take place between the cationic amphiphilic drug and phospholipids at the level of BMP-rich internal membranes of endosomes, impeding cholesterol sorting and leading to an accumulation of internal membranes, converting into multilamellar bodies. This process shows analogy to Niemann-Pick disease type C (NPC). Whereas the NPC-induced lipid traffic jam is situated at the cholesterol sorting proteins NPC1 and NPC2, the amiodarone-induced traffic jam is thought to be located at the BMP level, demonstrating its role in the mechanism of phospholipidosis-induction and its significance for use as a biomarker.

MeSH terms

  • Amiodarone / toxicity*
  • Animals
  • Biomarkers / blood
  • Biomarkers / urine
  • Cholesterol / blood
  • Gene Expression Regulation
  • Glycerophospholipids / blood
  • Glycerophospholipids / metabolism
  • Lipid Metabolism / drug effects*
  • Lipidoses / blood
  • Lipidoses / chemically induced*
  • Lipidoses / urine
  • Liver / pathology
  • Lung / pathology
  • Lymphocytes / drug effects
  • Lymphocytes / pathology
  • Lysophospholipids / blood*
  • Lysophospholipids / urine*
  • Male
  • Metabolic Networks and Pathways / drug effects
  • Oligonucleotide Array Sequence Analysis
  • Organ Size / drug effects
  • Phospholipids / blood
  • Rats
  • Rats, Sprague-Dawley
  • Spleen / pathology
  • Toxicogenetics

Substances

  • Biomarkers
  • Glycerophospholipids
  • Lysophospholipids
  • Phospholipids
  • didocosahexaenoyl bis(monoacylglycerol) phosphate
  • Cholesterol
  • Amiodarone