Lipid-Lowering Therapy With Ezetimibe Decreases Spontaneous Atherothrombotic Occlusions in a Rabbit Model of Plaque Erosion: A Role of Serum Oxysterols

Arterioscler Thromb Vasc Biol. 2018 Apr;38(4):757-771. doi: 10.1161/ATVBAHA.117.310244. Epub 2018 Feb 15.

Abstract

Objective: Plaque erosion is increasing its importance as one of the mechanisms of acute coronary syndromes in this statin era. However, the clinical efficacy of currently used lipid-lowering agents in the prevention of thrombotic complications associated with plaque erosion has not been clarified. Therefore, we examined the therapeutic effects of ezetimibe or rosuvastatin monotherapy on spontaneous atherothrombotic occlusion.

Approach and results: Femoral arteries of Japanese white rabbits, fed a high-cholesterol diet, were injured by balloon catheter, and then angiotensin II was continuously administrated. In 94% of these arteries, spontaneous thrombotic occlusions were observed after 5 weeks (median) of balloon injury. Histochemical analyses indicated that the injured arteries had similar pathological features to human plaque erosions; (1) spontaneous thrombotic occlusion, (2) lack of endothelial cells, and (3) tissue factor expression in vascular smooth muscle cells. Ezetimibe (1.0 mg/kg per day), but not rosuvastatin (0.6 mg/kg per day), significantly decreased thrombotic occlusion of arteries accompanied with accelerated re-endothelialization and the decreases of serum oxysterols despite the comparable on-treatment serum cholesterol levels. The 7-ketocholesterol inhibited the migration of human umbilical vein endothelial cells. Both 7-ketocholesterol and 27-hydroxycholesterol increased tissue factor expression in cultured rat vascular smooth muscle cells. Tissue factor expression was also induced by serum from vehicle- or rosuvastatin-treated rabbits, but the induction was attenuated with serum from ezetimibe-treated rabbits.

Conclusions: We have established a novel rabbit model of spontaneous atherothromobotic occlusion without plaque rupture that is feasible to test the therapeutic effects of various pharmacotherapies. Ezetimibe may decrease atherothrombotic complications after superficial plaque erosion by reducing serum oxysterols.

Keywords: acute coronary syndrome; ezetimibe; ketocholesterols; oxysterols; thrombosis.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin II
  • Animals
  • Anticholesteremic Agents / pharmacology*
  • Arterial Occlusive Diseases / blood
  • Arterial Occlusive Diseases / pathology
  • Arterial Occlusive Diseases / prevention & control*
  • Atherosclerosis / blood
  • Atherosclerosis / drug therapy*
  • Atherosclerosis / pathology
  • Biomarkers / blood
  • Cells, Cultured
  • Cholesterol, Dietary
  • Diet, High-Fat
  • Disease Models, Animal
  • Down-Regulation
  • Ezetimibe / pharmacology*
  • Femoral Artery / drug effects*
  • Femoral Artery / metabolism
  • Femoral Artery / pathology
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / pharmacology
  • Male
  • Oxysterols / blood*
  • Plaque, Atherosclerotic*
  • Rabbits
  • Rats
  • Rosuvastatin Calcium / pharmacology
  • Signal Transduction / drug effects
  • Thrombosis / blood
  • Thrombosis / pathology
  • Thrombosis / prevention & control*
  • Vascular System Injuries / blood
  • Vascular System Injuries / drug therapy*
  • Vascular System Injuries / pathology

Substances

  • Anticholesteremic Agents
  • Biomarkers
  • Cholesterol, Dietary
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Oxysterols
  • Angiotensin II
  • Rosuvastatin Calcium
  • Ezetimibe