Everolimus depletes plaque macrophages, abolishes intraplaque neovascularization and improves survival in mice with advanced atherosclerosis

Background and aims: Inhibition of the mechanistic target of rapamycin (mTOR) is a promising approach to halt atherogenesis in different animal models. This study evaluated whether the mTOR inhibitor everolimus can stabilize pre-existing plaques, prevent cardiovascular complications and improve survival in a mouse model of advanced atherosclerosis.

Methods: ApoE(-/-)Fbn1(C1039G+/-) mice (n = 24) were fed a Western diet (WD) for 12 weeks. Subsequently, mice were treated with everolimus (1.5 mg/kg daily) or vehicle for another 12 weeks while the WD continued.

Results: Despite hypercholesterolemia, everolimus treatment was associated with a reduction in circulating Ly6C(high) monocytes (15 vs. 28% of total leukocytes, p = 0.046), a depletion of plaque macrophages (2.1 vs. 4.1%, p = 0.040) and an abolishment of intraplaque neovascularization, which are all indicative of a more stable plaque phenotype. Moreover, everolimus reduced hypoxic brain damage and improved cardiac function, which led to increased survival (100 vs. 67% of animals, p = 0.038).

Conclusions: Everolimus enhances features of plaque stability and counters cardiovascular complications in ApoE(-/-)Fbn1(C1039G+/-) mice, even when administered at a later stage of the disease.