Studies that are emerging highlight the mechanistic relationship of TMAO to the development atherosclerosis in addition to its role as disease biomarker. The interplay between TMAO and bile acid metabolism mediated through multiple factors, such as the gut microbiome, farnesoid X receptor signaling, and flavin monooxygenase 3 activity may help identify another pathway by which atherosclerosis occurs. In this review, we discuss the most recent data regarding atherosclerosis, TMAO, and bile acid metabolism.

Rosuvastatin is commonly prescribed for the treatment of hypercholesterolemia and hepatic transporter-mediated accumulation in the liver enhances its efficacy. Current guidelines indicate no preference for fed or fasted rosuvastatin administration. We investigated the association between food intake and rosuvastatin disposition in healthy subjects and low-density lipoprotein cholesterol (LDL-C)-lowering effects among patients taking rosuvastatin. We demonstrate that administration with food resulted in a near 40% reduction of rosuvastatin exposure in healthy Asian (n = 12) and Caucasian (n = 11) subjects. Higher rosuvastatin concentrations in Asian subjects also correlated with higher allele frequency of ABCG2 c.421C>A. In mice, a greater rosuvastatin liver:plasma ratio was noted when administered with food. Among rosuvastatin patients (n = 156), there was no difference in dose needed to reach target LDL-C, measured LDL-C, or lathosterol concentrations, when administered in a fed or fasting state. Therefore, taking rosuvastatin with food could reduce systemic concentrations, and subsequent myopathy risk, without compromising LDL-C-lowering benefit.

Drug transporters are becoming increasingly recognized as relevant to the drug development process. This may be a reflection of increasing target complexity and the need for high-affinity interaction with drug targets that minimize off-target side effects. Moreover, as new molecular entities (NMEs) become larger in size and amphipathic in nature, interaction with drug transporters, both uptake as well as efflux, becomes increasingly likely. In some cases transporters may limit the absorption or organ-specific entry of NMEs, whereas in other cases transporters may enhance their absorption or tissue accumulation. Indeed, in some cases, transporters may prove to be a therapeutic target. Accordingly, a better understanding of potentially clinically relevant drug transporter polymorphisms earlier in the drug development process is highly desirable. In this review we examine key transporters that are important to the absorption, distribution, and excretion of a large number of drugs in clinical use. Importantly, we provide our assessment of the potential impact of known polymorphisms in such transporters and discuss whether there is sufficient evidence to incorporate these polymorphisms in the drug development process.

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