ABCA1 and atherosclerosis: After identifying the best LXR/RXR combination to augment ABCA1-dependent cholesterol efflux without eliciting toxicity, future directions should be devoted to identifying an efficient delivery system that precisely delivers LXR/RXR agonists into the endothelium of atheroprone and atherosclerotic lesions and test whether this delivery method is both safe and effective against treating and/or preventing atherosclerosis.