Drug Induced Phospholipidosis & Steatosis Assay

Introduction

  • Phospholipidosis is a lysosomal storage disorder characterized by excessive accumulation of intracellular phospholipids in tissues, such as the liver, kidney and lung. It is well established1 that a large number of cationic amphiphilic drugs have the potential to induce phospholipidosis. These include antibacterials, antipsychotics, antidepressants, antiantiginals, antimalarials, antiarrythmics, and cholesterol-lowering agents.
  • Several mechanisms have been proposed for drug-induced phospholipidosis, including inhibition of the enzymatic activity of phospholipidases2 and binding of the drug to the phospholipid to form drug-phospholipid complexes that cannot be broken down by phospholipidases1.
  • Phospholipidosis does not necessarily constitute toxicity, and can resolve by itself, but it predicts drug or metabolite accumulation that have led to liver, kidney, or respiratory failure. Consequently, in 2004 the FDA formed the Phospholipidosis Working Group to study the problem3,4 and recommend strategies for phospholipidosis screening studies.
  • Steatosis can result as a consequence of drugs interfering with hepatic lipid processing, leading to accumulation of triglycerides within the liver cells. This condition may lead to harmful liver inflammation, or steatohepatitis. Discontinuation of the offending drug generally leads to reversal of steatosis.
  • Accumulation of fatty acids as a consequence of steatosis have led to the recall of marketed drugs and revised therapeutic guidelines for the use of drugs (e.g. tetracycline and valproic acid)5.
  • Drug-induced phospholipidosis and steatosis is determined by measuring the accumulation of specific fluorescent probes in HepG2 cells or primary hepatocytes using High Content Screening.

Protocol

Drug Induced Phospholipidosis & Steatosis Cell-based Assay Protocol

References

TODO

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Caroline Bauch

Caroline Bauch

Principal Scientist

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Cyprotex enables and enhances the prediction of human exposure, clinical efficacy and toxicological outcome of a drug or chemical. By combining quality data from robust in vitro methods with contemporary in silico technology, we add value, context and relevance to the ADME-Tox data supplied to our partners in the pharmaceutical or chemical industries.