Liver ABCA1 deletion in LDLrKO mice does not impair macrophage reverse cholesterol transport or exacerbate atherogenesis

Arterioscler Thromb Vasc Biol. 2013 Oct;33(10):2288-96. doi: 10.1161/ATVBAHA.112.301110. Epub 2013 Jun 27.


Objective: Hepatic ATP binding cassette transporter A1 (ABCA1) expression is critical for maintaining plasma high-density lipoprotein (HDL) concentrations, but its role in macrophage reverse cholesterol transport and atherosclerosis is not fully understood. We investigated atherosclerosis development and reverse cholesterol transport in hepatocyte-specific ABCA1 knockout (HSKO) mice in the low-density lipoprotein (LDL) receptor KO (LDLrKO) C57BL/6 background.

Approach and results: Male and female LDLrKO and HSKO/LDLrKO mice were switched from chow at 8 weeks of age to an atherogenic diet (10% palm oil, 0.2% cholesterol) for 16 weeks. Chow-fed HSKO/LDLrKO mice had HDL concentrations 10% to 20% of LDLrKO mice, but similar very low-density lipoprotein and LDL concentrations. Surprisingly, HSKO/LDLrKO mice fed the atherogenic diet had significantly lower (40% to 60%) very low-density lipoprotein, LDL, and HDL concentrations (50%) compared with LDLrKO mice. Aortic surface lesion area and cholesterol content were similar for both genotypes of mice, but aortic root intimal area was significantly lower (20% to 40%) in HSKO/LDLrKO mice. Although macrophage (3)H-cholesterol efflux to apoB lipoprotein-depleted plasma was 24% lower for atherogenic diet-fed HSKO/LDLrKO versus LDLrKO mice, variation in percentage efflux among individual mice was <2-fold compared with a 10-fold variation in plasma HDL concentrations, suggesting that HDL levels, per se, were not the primary determinant of plasma efflux capacity. In vivo reverse cholesterol transport, resident peritoneal macrophage sterol content, biliary lipid composition, and fecal cholesterol mass were similar between both genotypes of mice.

Conclusions: The markedly reduced plasma HDL pool in HSKO/LDLrKO mice is sufficient to maintain macrophage reverse cholesterol transport, which, along with reduced plasma very low-density lipoprotein and LDL concentrations, prevented the expected increase in atherosclerosis.

Keywords: atherosclerosis; cardiovascular diseases; cholesterol; lipids; lipoproteins.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ATP Binding Cassette Transporter 1 / deficiency*
  • ATP Binding Cassette Transporter 1 / genetics
  • Animals
  • Aortic Diseases / etiology
  • Aortic Diseases / genetics
  • Aortic Diseases / metabolism*
  • Aortic Diseases / pathology
  • Apolipoprotein B-100
  • Apolipoproteins B / blood
  • Atherosclerosis / etiology
  • Atherosclerosis / genetics
  • Atherosclerosis / metabolism*
  • Atherosclerosis / pathology
  • Bile / metabolism
  • Biological Transport
  • Cell Line
  • Cholesterol / blood
  • Cholesterol / metabolism*
  • Cholesterol, HDL / blood
  • Cholesterol, LDL / blood
  • Cholesterol, VLDL / blood
  • Diet, Atherogenic
  • Disease Models, Animal
  • Feces / chemistry
  • Female
  • Liver / metabolism*
  • Macrophages, Peritoneal / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Receptors, LDL / deficiency*
  • Receptors, LDL / genetics
  • Time Factors


  • ABCA1 protein, mouse
  • ATP Binding Cassette Transporter 1
  • Apob protein, mouse
  • Apolipoprotein B-100
  • Apolipoproteins B
  • Cholesterol, HDL
  • Cholesterol, LDL
  • Cholesterol, VLDL
  • Receptors, LDL
  • Cholesterol