Implitapide

Although a change in life-style is often the method of first choice for lipid lowering, lipid-lowering drugs, in general, help to control elevated levels of different forms of lipids in patients with hyperlipidemia. While one group of drugs, statins, lowers cholesterol, the other group, fibrates, is known to take care of fatty acids and triglycerides. In addition, other drugs, such as ezetimibe, colesevelam, torcetrapib, avasimibe, implitapide, and niacin are also being considered to manage hyperlipidemia. As lipids are very critical for cardiovascular diseases, these drugs reduce fatal and nonfatal cardiovascular abnormalities in the general population. However, a number of recent studies indicate that apart from their lipid-lowering activities, statins and fibrates exhibit multiple functions to modulate intracellular signaling pathways, inhibit inflammation, suppress the production of reactive oxygen species, and modulate T cell activity. Therefore, nowadays, these drugs are being considered as possible therapeutics for several forms of human disorders including cancer, autoimmunity, inflammation, and neurodegeneration. Here I discuss these applications in the light of newly discovered modes of action of these drugs.

Microsomal triglyceride transfer protein (MTP) is essential for the synthesis of both chylomicron in the intestine and very low-density lipoprotein in the liver. An MTP inhibitor, (2S)-2-cyclopentyl-2-[4-[(2,4-dimethyl-9H-pyrido[2,3-b]indol-9-yl)methyl]phenyl]-N-[(1S)-2-hydroxy-1-phenylethyl]ethanamide (implitapide), has been shown to suppress atherosclerosis in apolipoprotein E knockout (apoE KO) mice. To elucidate the antiatherosclerotic mechanisms of implitapide in the mice, we examined the effects on plasma lipid levels, triglyceride (TG) elevation after oral fat loading, and development of atherosclerosis in apoE KO mice fed a Western-type diet. Implitapide at a dosage of approximately 3.2 mg/kg/day significantly reduced both total cholesterol and TG levels during the 8-week treatment period. In addition, implitapide significantly inhibited the increase in plasma TG levels after oral olive oil loading tests conducted after 4 weeks of treatment. After the treatment, implitapide significantly suppressed the atherosclerotic lesion area by 83% compared with a control group. These results provide direct evidence that the antiatherosclerotic effects of implitapide in apoE KO mice are associated with the inhibition of postprandial TG elevation, in addition to the reduction of both plasma total cholesterol and TG levels.