Liver X receptor activation promotes macrophage-to-feces reverse cholesterol transport in a dyslipidemic hamster model

J Lipid Res. 2010 Apr;51(4):763-70. doi: 10.1194/jlr.M001552. Epub 2009 Oct 27.

Abstract

Liver X receptor (LXR) activation promotes reverse cholesterol transport (RCT) in rodents but has major side effects (increased triglycerides and LDL-cholesterol levels) in species expressing cholesteryl ester transfer protein (CETP). In the face of dyslipidemia, it remains unclear whether LXR activation stimulates RCT in CETP species. We therefore used a hamster model made dyslipidemic with a 0.3% cholesterol diet and treated with vehicle or LXR agonist GW3965 (30 mg/kg bid) over 10 days. To investigate RCT, radiolabeled (3)H-cholesterol macrophages or (3)H-cholesteryl oleate-HDL were then injected to measure plasma and feces radioactivity over 72 or 48 h, respectively. The cholesterol-enriched diet increased VLDL-triglycerides and total cholesterol levels in all lipoprotein fractions and strongly increased liver lipids. Overall, GW3965 failed to improve both dyslipidemia and liver steatosis. However, after (3)H-cholesterol labeled macrophage injection, GW3965 treatment significantly increased the (3)H-tracer appearance by 30% in plasma over 72 h, while fecal (3)H-cholesterol excretion increased by 156% (P < 0.001). After (3)H-cholesteryl oleate-HDL injection, GW3965 increased HDL-derived cholesterol fecal excretion by 64% (P < 0.01 vs. vehicle), while plasma fractional catabolic rate remained unchanged. Despite no beneficial effect on dyslipidemia, LXR activation promotes macrophage-to-feces RCT in dyslipidemic hamsters. These results emphasize the use of species with a more human-like lipoprotein metabolism for drug profiling.

MeSH terms

  • Animals
  • Benzoates / pharmacology*
  • Benzoates / therapeutic use
  • Benzylamines / pharmacology*
  • Benzylamines / therapeutic use
  • Bile Acids and Salts / analysis
  • Biological Transport / drug effects
  • Cardiovascular Diseases / drug therapy
  • Cell Line
  • Cholesterol / administration & dosage
  • Cholesterol / blood
  • Cholesterol / metabolism*
  • Cricetinae
  • Disease Models, Animal
  • Dyslipidemias / blood
  • Dyslipidemias / etiology
  • Dyslipidemias / metabolism*
  • Fatty Liver / etiology
  • Feces / chemistry
  • Gene Expression Regulation / drug effects
  • Intestinal Absorption / genetics
  • Lipid Metabolism / drug effects
  • Lipoproteins / blood
  • Lipoproteins, HDL / administration & dosage
  • Lipoproteins, HDL / blood
  • Lipoproteins, HDL / metabolism
  • Liver / drug effects
  • Liver / metabolism
  • Liver X Receptors
  • Macrophages / metabolism
  • Mesocricetus
  • Mice
  • Orphan Nuclear Receptors / agonists*
  • RNA, Messenger / metabolism
  • Time Factors

Substances

  • Benzoates
  • Benzylamines
  • Bile Acids and Salts
  • GW 3965
  • Lipoproteins
  • Lipoproteins, HDL
  • Liver X Receptors
  • Orphan Nuclear Receptors
  • RNA, Messenger
  • lipoprotein cholesterol
  • Cholesterol