Inhibition of cholesteryl ester synthesis by polyacetylenes from Atractylodes rhizome.

Using activity guided purification, four known compounds, sesquiterpene atractylenolide III (1), and the polyacetylenes 14-acetoxy-12-senecioyloxytetradeca-2E,8E,10E-trien-4,6-diyn-1-ol (2), 14-acetoxy-12-α-methylbutyl-2E,8E,10E-trien-4,6-diyn-1-ol (3), and 14-acetoxy-12-ß -methylbutyl-2E,8E,10E-trien-4,6-diyn-1-ol (4), were isolated from a traditional herbal medicine, Atractylodes rhizome. Structurally similar 3 and 4 (3/4 mixture) were obtained as a mixture. In intact Chinese hamster ovary (CHO) K1 cell assays, 1, 2, and a 3/4 mixture selectively inhibited cholesterol [14C]oleate synthesis from [14C]oleate with IC50 values of 73.5 µM, 35.4 µM, and 10.2 µM, respectively, without any effects on cytotoxicity. As a potential target of these inhibitors involved in cholesteryl ester (CE) synthesis, effects on sterol O-acyltransferase (SOAT) activity were investigated using microsomes prepared from CHO-K1 cells as an enzyme source. Hence, these compounds inhibit SOAT activity with IC50 values (211 µM for 1, 29.0 µM for 2, and 11.8 µM for 3/4 mixture) that correlate well with those measured from intact cell assays. Our results strongly suggest that these compounds inhibit CE synthesis by blocking SOAT activity in CHO-K1 cells.

Effects of oolonghomobisflavan A on oxidation of low-density lipoprotein.

Oxidation of low-density lipoprotein (LDL) by reactive oxygen species (ROS) and reactive nitrogen species (RNS) has been suggested to be involved in the onset of atherosclerosis. Oolong tea contains unique polyphenols including oolonghomobisflavan A (OFA). In this study, the effects of OFA on LDL oxidation by ROS and RNS were investigated in vitro. OFA suppressed formation of cholesterol ester hydroperoxides in LDL oxidized by peroxyl radical and peroxynitrite, and formation of thiobarbituric acid reactive substances in LDL oxidized by Cu2+. In addition, OFA inhibited fragmentation, carbonylation, and nitration of apolipoprotein B-100 (apo B-100) in the oxidized LDL, in which heparin-binding activity of apo B-100 was protected by OFA. Our results suggest that OFA exhibits antioxidant activity against both lipid peroxidation and oxidative modification of apo B-100 in LDL oxidized by ROS and RNS. Polyphenols in oolong tea may prevent atherosclerosis by reducing oxidative stress.

Inhibitors for cholesterol ester accumulation in macrophages from Chinese cabbage.

The cholesterol ester accumulates in macrophages in the early stage of atherosclerotic lesions, leading to the formation of foam cells. We examined the inhibitory effects of the crude extracts of 22 edible plants on foam cell formation and isolated nine chlorophyll derivatives as potent inhibitors from Chinese cabbage. The results of the present study suggest that the chlorophyll derivatives contained in edible plants may be useful for the prevention and treatment of atherosclerosis.

Bafilomycin L, a new inhibitor of cholesteryl ester synthesis in mammalian cells, produced by marine-derived Streptomyces sp. OPMA00072.

Marine-derived Streptomyces sp. OPMA00072 was found to produce inhibitors of the synthesis of neutral lipids in a cell-based assay using Chinese hamster ovary (CHO) cells. A new 16-membered macrolide named bafilomycin L (BFL) (1) was isolated along with the known structurally related bafilomycin C1 (BFC1) (3) from the culture broth of the actinomycete by solvent extraction, octadecylsilyl column chromatography and HPLC. BFL inhibited cholesteryl ester (CE) synthesis in CHO cells with an IC50 value of 0.83 nM and also in mouse peritoneal macrophages with an IC50 of 6.1 nM. In addition, BFL blocked cellular acidification in HeLa cells by interfering with vacuolar H(+)-ATPase (V-ATPase) as well as other bafilomycins. These data strongly suggest that BFL disturbed the lysosome function to block cholesterol metabolism, leading to the inhibition of CE accumulation in mammalian cells.

Caffeoyl triterpenes from pear (Pyrus pyrifolia Nakai) fruit peels and their antioxidative activities against oxidation of rat blood plasma.

Six triterpenes, including three caffeoyl triterpenes, were purified and isolated from pear fruit ( Pyrus pyrifolia Nakai cv. Chuwhangbae) peel extracts using various column chromatography techniques with a guided 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay. The isolated compounds were identified as betulinic aldehyde (1), lupeol (2), betulinic acid (3), 3-O-cis-caffeoylbetulinic acid (4), 3-O-trans-caffeoylbetulinic acid (5), and 3-O-trans-caffeoyloleanolic acid (6) on the basis of nuclear magnetic resonance spectroscopy and electrospray ionization mass spectrometry. Four compounds (1, 4-6) were identified from Asian pear fruit for the first time. In addition, compounds 4-6, containing a caffeic acid moiety, showed higher DPPH radical-scavenging and suppression effects against copper ion-induced oxidation of rat blood plasma than other compounds without a caffeic acid moiety.

SREBP2 mediates the modulation of intestinal NPC1L1 expression by curcumin.

Curcumin, the major phenolic compound in the spice turmeric, exhibits numerous biological effects, including lowering plasma cholesterol and preventing diet-induced hypercholesterolemia. The mechanisms underlying the hypocholesterolemic effect of curcumin are not fully understood. In this regard, intestinal Niemann-Pick C1-like 1 (NPC1L1) cholesterol transporter, the molecular target of intestinal cholesterol absorption inhibitor ezetimibe, plays an essential role in the maintenance of cholesterol homeostasis. The current studies were designed to investigate the effect of curcumin on NPC1L1 function, expression, and promoter activity in intestinal Caco-2 monolayers. NPC1L1 function was evaluated by the measurement of ezetimibe-sensitive [(3)H]cholesterol esterification. Relative abundance of NPC1L1 mRNA and protein was evaluated by real-time PCR and Western blotting, respectively. Luciferase assays were used to measure NPC1L1 promoter activity. Our results showed that curcumin significantly inhibited ezetimibe-sensitive cholesterol esterification in a dose-dependent manner with a maximum decrease (by 52% compared with control) occurring at 50 µM concentration. Curcumin treatment of Caco-2 monolayers also significantly decreased NPC1L1 mRNA and protein expression. Similarly, the promoter activity of the NPC1L1 gene was inhibited significantly (55%) by 50 µM curcumin. The decrease in NPC1L1 promoter activity by curcumin was associated with a reduction in the expression and the DNA-binding activity of the sterol response element-binding protein 2 (SREBP2) transcription factor. Furthermore, the overexpression of active SREBP2 protected NPC1L1 from the inhibitory effect of curcumin. Our studies demonstrate that curcumin directly modulates intestinal NPC1L1 expression via transcriptional regulation and the involvement of SREBP2 transcription factor.

Cholesterol myristate suppresses the apoptosis of mesenchymal stem cells via upregulation of inhibitor of differentiation.

To identify small molecules that suppress the apoptosis of mesenchymal stem cells (MSCs) is promising for stem cell therapy. We recently showed that bone morphogenetic protein 4 (BMP4) signalling involves the effect of cholesterol myristate on the proliferation of MSCs. The present study evaluated the effects of cholesterol myristate on the apoptosis of MSCs and the inhibitor of differentiation (Id1), target gene of BMP4 signalling. MSCs transfected by the Id1 promoter reporter construct, cholesterol myristate increases the activity of Id1 promoter. However, structurally related steroids such as cholesterol, ß-sitosterol and cholesten-3-one, lack of the myristate, did not affect the activity of Id1 promoter, suggesting that myristate is essential for this effect. This effect depends on BMP signalling. Apoptosis analysis indicated that cholesterol myristate inhibited the apoptosis of MSCs induced by serum-free. Cholesterol myristate increases the expression of Id1 and its target gene bcl-x/l in MSCs treated with serum-free. Moreover, noggin, a BMP antagonist, reduced the anti-apoptotic effects of cholesterol myristate. Thus, this study aims to provide evidence that cholesterol myristate suppresses the apoptosis of MSCs via up-regulation of Id1. These findings can be applied for improving MSCs survival in stem-cell transplantation, bone-marrow transplantation, treatment of bone diseases such as osteoporosis and chemotherapy.

Panax notoginseng saponins decrease cholesterol ester via up-regulating ATP-binding cassette transporter A1 in foam cells.

AIM: Accumulating evidence has indicated that Panax notoginseng saponins (PNS), the major ingredients in Panax notoginseng (Burk.) F.H. Chen which could be found widely in Asia, can attenuate atherogenesis in vivo. This study was designed to examine the relationship of PNS with cholesterol ester in foam cells sourced from macrophages and the effect of PNS on the expression of ATP-binding cassette transporter A1 (ABCA1). MATERIALS AND METHODS: Foam cells sourced from macrophages were cultured with PNS. The content of cholesterol ester in foam cells was analyzed and expressions of ABCA1 and liver X receptor α (LXRα) in foam cells were measured by real-time PCR and western blotting methods. RESULTS: The results showed that PNS could significantly decrease the level of cholesterol ester in foam cells at middle and high dosages. The real-time PCR and western blotting assays indicated that the expression of ABCA1 was up-regulated by PNS in a dose-dependent manner. Analysis based on these results showed that the cholesterol ester level was negatively correlated with ABCA1 expression. CONCLUSIONS: As a result, we conclude that by up-regulating the expression of ABCA1, PNS could lower the cholesterol ester level, which resulted in the attenuation of the foam cell formation. This bioactivity might be associated with the special chemical structures of PNS that are similar to the natural agonist of LXRα.

Rimonabant is a dual inhibitor of acyl CoA:cholesterol acyltransferases 1 and 2.

Acyl coenzyme A:cholesterol acyltransferase (ACAT) catalyzes the intracellular synthesis of cholesteryl esters (CE). Both ACAT isoforms, ACAT1 and ACAT2, play key roles in the pathophysiology of atherosclerosis and ACAT inhibition retards atherosclerosis in animal models. Rimonabant, a type 1 cannabinoid receptor (CB1) antagonist, produces anti-atherosclerotic effects in humans and animals by mechanisms which are not completely understood. Rimonabant is structurally similar to two other cannabinoid receptor antagonists, AM251 and SR144528, recently identified as potent inhibitors of ACAT. Therefore, we examined the effects of Rimonabant on ACAT using both in vivo cell-based assays and in vitro cell-free assays. Rimonabant dose-dependently reduced ACAT activity in Raw 264.7 macrophages (IC(50)=2.9+/-0.38 microM) and isolated peritoneal macrophages. Rimonabant inhibited ACAT activity in intact CHO-ACAT1 and CHO-ACAT2 cells and in cell-free assays with approximately equal efficiency (IC(50)=1.5+/-1.2 microM and 2.2+/-1.1 microM for CHO-ACAT1 and CHO-ACAT2, respectively). Consistent with ACAT inhibition, Rimonabant treatment blocked ACAT-dependent processes in macrophages, oxysterol-induced apoptosis and acetylated-LDL induced foam cell formation. From these results we conclude that Rimonabant is an ACAT1/2 dual inhibitor and suggest that some of the atherosclerotic beneficial effects of Rimonabant are, at least partly, due to inhibition of ACAT.

Taurine reduces the secretion of apolipoprotein B100 and lipids in HepG2 cells.

BACKGROUND: Higher concentrations of serum lipids and apolipoprotein B100 (apoB) are major individual risk factors of atherosclerosis and coronary heart disease. Therefore ameliorative effects of food components against the diseases are being paid attention in the affluent countries. The present study was undertaken to investigate the effect of taurine on apoB secretion and lipid metabolism in human liver model HepG2 cells. RESULTS: The results demonstrated that an addition of taurine to the culture media reduces triacylglycerol (TG)-mass in the cells and the medium. Similarly, cellular cholesterol-mass was decreased. Taurine inhibited the incorporation of [14C] oleate into cellular and medium TG, suggesting the inhibition of TG synthesis. In addition, taurine reduced the synthesis of cellular cholesterol ester and its secretion, suggesting the inhibition of acyl-coenzyme A:cholesterol acyltransferase activity. Furthermore, taurine reduced the secretion of apoB, which is a major protein component of very low-density lipoprotein. CONCLUSION: This is a first report to demonstrate that taurine inhibits the secretion of apoB from HepG2 cells.

Liver-specific inhibition of acyl-coenzyme a:cholesterol acyltransferase 2 with antisense oligonucleotides limits atherosclerosis development in apolipoprotein B100-only low-density lipoprotein receptor-/- mice.

OBJECTIVE: The purpose of this study was to determine the effects of liver-specific inhibition of acyl-coenzyme A:cholesterol acyltransferase 2 (ACAT2) on the development of hypercholesterolemia and atherosclerosis in mice. METHODS AND RESULTS: Apolipoprotein B100-only low-density lipoprotein (LDL) receptor-/- mice were given saline, a nontargeting control antisense oligonucleotide (ASO), or ASOs targeting ACAT2 biweekly for a period spanning 16 weeks. Mice treated with ACAT2 targeting ASOs had liver-specific reduction in ACAT2 mRNA, yet intestinal ACAT2 and cholesterol absorption was left undisturbed. ASO-mediated knockdown of ACAT2 resulted in reduction of total plasma cholesterol, increased levels of plasma triglyceride, and a shift in LDL cholesteryl ester (CE) fatty acid composition from mainly saturated and monounsaturated to polyunsaturated fatty acid enrichment. Furthermore, the liver-specific depletion of ACAT2 resulted in protection against diet-induced hypercholesterolemia and aortic CE deposition. This is the first demonstration that specific pharmacological inhibition of ACAT2, without affecting ACAT1, is atheroprotective. CONCLUSIONS: Hepatic ACAT2 plays a critical role in driving the production of atherogenic lipoproteins, and therapeutic interventions, such as the ACAT2-specific ASOs used here, which reduce acyltransferase 2 (ACAT2) function in the liver without affecting ACAT1, may provide clinical benefit for cardiovascular disease prevention.

Sespendole, a new inhibitor of lipid droplet synthesis in macrophages, produced by Pseudobotrytis terrestris FKA-25.

Sespendole was isolated as an inhibitor of lipid droplet formation in macrophages from the culture broth of a fungal strain Pseudobotrytis terrestris FKA-25. The compound inhibited the synthesis of cholesteryl ester and triacylglycerol by mouse macrophages with IC50 values of 4.0 and 3.2 microM, respectively.

Synthesis and biological evaluation of a beauveriolide analogue library.

Synthesis of beauveriolide III (1b), which is an inhibitor of lipid droplet accumulation in macrophages, was achieved by solid-phase assembly of linear depsipeptide using a 2-chlorotrityl linker followed by solution-phase cyclization. On the basis of this strategy, a combinatorial library of beauveriolide analogues was carried out by radio frequency-encoded combinatorial chemistry. After automated purification using preparative reversed-phase HPLC, the library was tested for inhibitory activity of CE synthesis in macrophages to determine structure-activity relationships of beauveriolides. Among them, we found that diphenyl derivative 7{9,1} is 10 times more potent than 1b.

Cholesterol and its anionic derivatives inhibit 5-lipoxygenase activation in polymorphonuclear leukocytes and MonoMac6 cells.

5-Lipoxygenase (5-LO) is the key enzyme in the biosynthesis of leukotrienes (LTs), biological mediators of host defense reactions and of inflammatory diseases. While the role of membrane binding in the regulation of 5-LO activity is well established, the effects of lipids on cellular activity when added to the medium has not been characterized. Here, we show such a novel function of the most abundant sulfated sterol in human blood, cholesterol sulfate (CS), to suppress LT production in human polymorphonuclear leukocytes (PMNL) and Mono Mac6 cells. We synthesized another anionic lipid, cholesterol phosphate, which demonstrated a similar capacity in suppression of LT synthesis in PMNL. Cholesteryl acetate was without effect. Cholesterol increased the effect of CS on 5-LO product synthesis. CS and cholesterol also inhibited arachidonic acid (AA) release from PMNL. Addition of exogenous AA increased the threshold concentration of CS required to inhibit LT synthesis. The effect of cholesterol and its anionic derivatives can arise from remodeling of the cell membrane, which interferes with 5-LO activation. The fact that cellular LT production is regulated by sulfated cholesterol highlights a possible regulatory role of sulfotransferases/sulfatases in 5-LO product synthesis.

Aortic drug delivery of dexamethasone palmitate incorporated into lipid microspheres and its antiatherosclerotic effect in atherogenic mice.

In order to confirm the efficacy of dexamethasone (DXM) palmitate incorporated into lipid microspheres (d-lipo) on atherosclerosis, the aortic drug delivery by d-lipo and its antiatherosclerotic effect were investigated. In an in vitro uptake experiment, d-lipo or DXM was added to macrophages and foam cells, and then incubated for 1, 4, 8 and 24 h at 37 degrees C. The uptake of drug by these cells after addition of d-lipo was higher than that of DXM at each time point. In an in vitro pharmacological experiment, the macrophages and foam cells were incubated with d-lipo or DXM for 24 h at 37 degrees C. The inhibitory effect of d-lipo on cellular cholesterol ester (CE) accumulation in these cells was significantly more potent than that of DXM. In an in vivo pharmacokinetic experiment, d-lipo or DXM was intravenously administered to atherogenic mice, and then aorta was collected at 1, 8, and 24 h after administration. The aortic drug concentration after administration of d-lipo to atherogenic mice was higher than that of DXM at each time point. In an in vivo pharmacological experiment, d-lipo or DXM was intravenously administered to atherogenic mice once a week for 7 weeks. The inhibitory effect of d-lipo on the aortic CE accumulation in atherogenic mice was significantly more potent than that of DXM. These findings suggest that efficient drug delivery to the atherosclerotic lesions by d-lipo produces an excellent antiatherosclerotic effect at a lower dose. Therefore, d-lipo may be useful for the development of drug delivery systems for atherosclerotic therapy.

Inhibitory effects of N-(3,5-dimethoxy-4-n-octyloxycinnamoyl)-N'-(3,4-dimethylphenyl)piperazine (YIC-C8-434), an acyl-CoA:cholesterol O-acyltransferase inhibitor, on cholesterol esterification in the intestine and liver.

The effects of an acyl-CoA:cholesterol O-acyltransferase (ACAT) inhibitor, N-(3,5-dimethoxy-4-n-octyloxycinnamoyl)-N'-(3,4-dimethylphenyl)piperazine (YIC-C8-434), on cholesterol esterification in the intestine and liver were investigated in vitro and in vivo. YIC-C8-434 inhibited the formation of cholesteryl [(3)H]oleate from [(3)H]oleic acid and cholesterol both in human colon adenocarcinoma Caco2 cells and in human hepatoma HepG2 cells with IC(50) values of 0.38 and 0.49 microM, respectively. However, it did not influence the incorporation of [(3)H]oleic acid into triacylglycerols and phospholipids. Oral administration of YIC-C8-434 at a dose of 8.3 mg/kg/d inhibited [(14)C]cholesterol absorption by 17% (p<0.01) in rats. YIC-C8-434 also significantly reduced the secretion of very low-density lipoprotein (VLDL) cholesterol from the liver into the plasma at an oral dose of 100 mg/kg/d after an intravenous injection of Triton WR-1339. These results suggest that oral administration of YIC-C8-434 reduces intestinal cholesterol absorption and hepatic VLDL cholesterol secretion by direct inhibition of ACAT in the intestinal epithelium and hepatocytes, respectively. However, the inhibitory action of YIC-C8-434 on cholesterol absorption rather than hepatic cholesterol secretion may play a more important role in its hypocholesterolemic activity, because the effective dose for the former was 12-fold lower than that for the latter.

[Screening of microbial secondary metabolites inhibiting cholesterol biosynthesis with the use of hepatoblastoma G2]. / Otbor mikrobnykh vtorichnykh matabolitov--ingibitorov biosinteza kholesterina s pomozh'iu kul'tury kletok gepatoblastomy G2.

The culture of hepatoblastoma G2 (Hep G2) cells is proposed as an effective model for screening of microbial metabolites--inhibitors of sterol biosynthesis. This model can be applied at early stages of screening procedures and is quite effective for testing of crude extracts of producers' culture broth. The test is based on measurement inhibition of the radiolabelled precursors incorporation in cholesterol and separate fractions of lipids by microbial metabolites in Hep G2 cells. That allows not only to reveal inhibitors of cholesterol biosynthesis, but also to evaluate mechanism of action, including ability to inhibit the synthesis of cholesterol ethers. The cholesterol biosynthesis inhibition was tested at 150 microbial cultures (actinomycetes and imperfect fungi), isolated from soil. The ability to inhibit 14C-acetate incorporation into cholesterol was found in 15-20% of microbial cultures possessing antifungal activity of extracts (culture broth and mycelium).

Stabilization of caveolin-1 by cellular cholesterol and scavenger receptor class B type I.

Caveolae are 50-100 nm plasma membrane invaginations, which function in cell signaling, in transcytosis, and in regulating cellular cholesterol homeostasis. These subcompartments of the plasma membrane are characterized by the presence of caveolin proteins. Recent studies have indicated that caveolae may be involved in the regulation of cellular cholesterol efflux to high-density lipoproteins (HDL), as well as selective cholesteryl ester uptake mediated by scavenger receptor class B type I (SR-BI). In the present studies, we show that caveolin-1 expression in HEK-293T cells has no effect on SR-BI-mediated cellular cholesterol efflux to reconstituted HDL. However, SR-BI-mediated selective cholesteryl ester uptake is significantly inhibited by caveolin-1. Interestingly, we also found that SR-BI, but not CD36, can induce the dramatic stabilization of the caveolin-1 protein, independently of its transcriptional control. On the other hand, caveolin-1 has little effect on SR-BI stability, but clearly increases CD36 stability. Since SR-BI expression has been shown to increase cellular cholesterol levels, we next examined the effect of cholesterol itself on caveolin-1 stabilization and localization. When cells were loaded with cholesterol, we observed the dramatic stabilization of caveolin-1 with significant clustering of caveolin-1 at the cell surface. In addition, a palmitoylation-deficient caveolin-1 mutant was still responsive to cholesterol-induced stabilization, indicating that palmitoylation of caveolin-1 is not required for the cholesterol-induced stabilization of caveolin-1. These results suggest an important role for cholesterol and SR-BI in the regulation of caveolin functioning, especially in cell types such as endothelial cells and macrophages, which can be dramatically affected by changes in their cholesterol content during the development of atherosclerosis.

Sex-related differences in the regulation of macrophage cholesterol metabolism.

Men have an earlier onset and higher incidence of coronary heart disease than women, independent of environmental risk factor exposure. As a consequence, there has been considerable interest in the potential role of sex hormones in atherogenesis. An emerging body of evidence suggests that sex-specific tissue and cellular characteristics may mediate sex-specific responses to a variety of stimuli. Recent studies have shown that oestrogen, progesterone and androgens all regulate processes integral to human macrophage foam cell formation, a key event in atherogenesis, in a sex-specific manner; findings that may have important implications for understanding the sex gap in atherosclerosis. Physiological levels of 17beta-estradiol and progesterone are both associated with a female-specific reduction in cholesteryl ester accumulation in human macrophages. By contrast, androgens increase cholesteryl ester formation in male but not in female donor human macrophages. This review summarizes current data concerning the sex-specific effects of sex hormones on processes important to macrophage foam cell formation and the basic mechanisms responsible for the sex specificity of such effects. Future research in this promising field may eventually lead to the novel concept of 'sex-specific' treatments directed at inhibiting atherogenesis.

Ezetimibe, a potent cholesterol absorption inhibitor, normalizes combined dyslipidemia in obese hyperinsulinemic hamsters.

Ezetimibe potently and selectively inhibits cholesterol absorption in the intestine, thereby reducing plasma cholesterol in preclinical models of hypercholesterolemia. Clinical trials have demonstrated that ezetimibe lowers LDL cholesterol and raises HDL cholesterol in humans. The effect of ezetimibe on other dyslipidemias, particularly hypertriglyceridemia, is not yet known. In the present studies, we assessed the effect of ezetimibe on combined hypercholesterolemia and hypertriglyceridemia in obese hyperinsulinemic hamsters. Hamsters were fed chow, chow with cholesterol (0.12%), or the same cholesterol diet containing different dietary triglycerides (15%) in the absence or presence of 1 mg/kg ezetimibe (in diet) for up to 84 days. Body weight, serum insulin, leptin, glucose, cholesterol, and triglyceride levels were analyzed. Cholesterol and triglyceride levels were also determined in VLDL+IDL, LDL, and HDL. Hamsters maintained on high-fat diets became obese, hyperinsulinemic, hyperleptinemic, hypercholesterolemic, and hypertriglyceridemic. Ezetimibe did not affect body weight, insulin, or leptin, but ablated the combined hypercholesterolemia and hypertriglyceridemia induced by high-fat diets. Ezetimibe normalized VLDL+IDL cholesterol and triglyceride and significantly decreased LDL cholesterol to below chow-fed levels. The ratio of HDL to LDL cholesterol increased significantly with the addition of ezetimibe. Ezetimibe completely eliminated the accumulation of cholesteryl ester and free cholesterol in liver that was induced under the various dietary conditions in the absence of drug. In conclusion, ezetimibe is very effective in correcting the combined dyslipidemia in diet-induced obese hyperinsulinemic hamsters and may be an effective therapy for ameliorating combined dyslipidemia in obese insulin-resistant and/or type 2 diabetic humans.