Liver X
nuclear receptor (LXR) agonists are promising anti-atherosclerotic agents that increase the expression of
cholesterol transporters on
atheroma macrophages leading to increased efflux of
cholesterol to endogenous
high-density lipoprotein (HDL) acceptors. HDL subsequently delivers effluxed
cholesterol to the liver by the process of reverse
cholesterol transport, resulting in reduction of
atherosclerotic plaques. However, LXR agonists administration triggers undesirable
liver steatosis and
hypertriglyceridemia due to increased
fatty acid and
sterol synthesis. LXR-induced liver toxicity, poor drug aqueous solubility and low levels of endogenous HDL acceptors in target patient populations limit the clinical translation of LXR agonists. Here, we propose a dual-antiatherogenic strategy for administration of the LXR agonist,
T0901317 (T1317), by encapsulating in synthetic HDL (sHDL) nanoparticles. sHDL had been clinically proven to serve as
cholesterol acceptors, resulting in plaque reduction in
atherosclerosis patients. In addition, the hydrophobic core and endogenous
atheroma-targeting ability of sHDL allow for encapsulation of water-insoluble drugs and their subsequent delivery to
atheroma. Several compositions of sHDL were tested to optimize both T1317 encapsulation efficiency and ability of T1317-sHDL to efflux
cholesterol. Optimized T1317-sHDL exhibited more efficient
cholesterol efflux from macrophages and enhanced
atheroma-targeting relative to free drug. Most importantly, in an
apolipoprotein E deficient (
ApoE-/-)
atherosclerosis progression murine model, T1317-sHDL showed superior inhibition of
atherogenesis and reduced
hypertriglyceridemia side effects in comparison to the free drug and blank sHDL. The T1317-sHDL pharmacological efficacy was observed at doses lower than those previously described for LXR agents, which may have additional safety benefits. In addition, the established clinical manufacturing, safety and efficacy of blank sHDL nanoparticles used in this study could facilitate future clinical translation of LXR-loaded sHDLs.