Prevention of atherosclerosis by the mTOR inhibitor everolimus in LDLR-/- mice despite severe hypercholesterolemia

Atherosclerosis. 2008 May;198(1):39-48. doi: 10.1016/j.atherosclerosis.2007.09.019. Epub 2007 Nov 5.

Abstract

Everolimus inhibits the mammalian target of rapamycin (mTOR) in proliferating cells. It is widely used in transplant patients and has also been exploited by drug-eluting stents for the treatment of cardiovascular disease. However, there is only limited data on the pathophysiological effects of mTOR-inhibitors on the vascular wall. We aimed to unravel the effects of everolimus on cholesterol-induced atherosclerosis and on circulating cell mediators in LDL-receptor-deficient (LDLR(-/-)) mice. Male hypercholesterolemic LDLR(-/-) mice received either solvent (group A; n=28) or everolimus at 0.05 mg/kg (group B, n=22) and 1.5 mg/kg (group C, n=29) per body weight per day by subcutaneously implanted osmotic minipumps for the study period of 12 weeks. Group B showed 44% reduction of atherosclerotic lesions at the brachiocephalic artery (BCA). In group C atherosclerotic lesions were reduced by 85% in the BCA and by 60% at the aortic root. This was associated with a significantly lower complexity of lesions in both treated groups (p<0.001) and despite a 40% increase of plasma cholesterol. Everolimus caused a significant reduction of circulating cell mediators such as interleukin-1alpha, interleukin-5, GM-CSF and interleukin-12p40. Everolimus increased the plasma levels of KC but had no effect on eighteen other circulating cell mediators studied. Everolimus strongly inhibits atherosclerosis development in LDL-receptor(-/-) mice despite severe hypercholesterolemia. Everolimus application had only small effects on circulating cell mediators. The significant reduction of atherosclerotic lesions was associated with a delayed transition from early macrophages enriched lesions to advanced atherosclerotic plaques.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Atherosclerosis / etiology
  • Atherosclerosis / pathology
  • Atherosclerosis / prevention & control*
  • Body Weight / drug effects
  • Cholesterol, LDL / blood
  • Cytokines / blood
  • Everolimus
  • Hypercholesterolemia / complications
  • Hypercholesterolemia / drug therapy*
  • Hypercholesterolemia / pathology
  • Immunosuppressive Agents / blood
  • Immunosuppressive Agents / pharmacology*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Protein Kinases / metabolism*
  • Receptors, LDL / genetics*
  • Severity of Illness Index
  • Sirolimus / analogs & derivatives*
  • Sirolimus / blood
  • Sirolimus / pharmacology
  • TOR Serine-Threonine Kinases

Substances

  • Cholesterol, LDL
  • Cytokines
  • Immunosuppressive Agents
  • Receptors, LDL
  • Everolimus
  • Protein Kinases
  • mTOR protein, mouse
  • TOR Serine-Threonine Kinases
  • Sirolimus