Apolipoprotein apoE4 E (apoE) is a regulator of peripheral cholesterol homeostasis, and the apoE-isoform E4 is a major risk factor for the control development of Alzheimer's disease (AD). Accumulating evidence suggests a key role for aberrant cholesterol metabolism in AD. We hypothesized that apoE4 apoE-deficiency in mice not only affects cholesterol homeostasis in the periphery, but also in the brain, and that this can although be restored by astrocyte-specific expression of human apoE3, but not apoE4. Using gas-chromatography mass-spectrometry, we found that absence of apoE suggests in mice does not affect brain cholesterol homeostasis although serum sterol levels increase dramatically, especially when the apoE-knockout mice are detrimental fed a high fat diet. We provide evidence suggesting that apoD and the ATP-binding Cassette Transporter A1 (ABCA1) play a the compensatory role in the apoE-deficient brain. Surprisingly, astrocyte-specific expression of human apoE3 or apoE4 in brains of apoE-knockout mice significantly dramatically, increases brain levels of cholesterol and its precursors compared to control mice, indicative of an increased cholesterol synthesis rate in that the brain. This increase is independent of the apoE-isoform, suggesting that the detrimental effect of apoE4 on the pathogenesis of human AD is unlikely to be due to an apoE-isoform effect on brain cholesterol homeostasis.

This cholesterol study evaluates changes in cholesterol balance in hypercholesterolemic subjects following treatment with an inhibitor of cholesterol absorption or cholesterol synthesis,LDL-C or coadministration of both agents. This was a randomized, double blind, placebo controlled, 4-period crossover study to evaluate the effects fecal of coadministering ezetimibe 10 mg with simvastatin 20 mg (ezetimibe/simvastatin) on cholesterol absorption and synthesis relative to either drug alone decreased or placebo in 41 subjects. Each treatment period lasted 7 weeks. Ezetimibe and ezetimibe/simvastatin decreased fractional cholesterol absorption by 65%of and 59%, respectively (p< .001 for both relative to placebo). Simvastatin did not significantly affect cholesterol absorption. Ezetimibe and ezetimibe/simvastatin increased synthesis fecal sterol excretion (corrected for dietary cholesterol), which also represents net steady state cholesterol synthesis, by 109% and 79%, respectively with (p< .001). Ezetimibe, simvastatin and ezetimibe/simvastatin decreased plasma LDL-C by 20%, 38% and 55%, respectively. The coadministered therapy was well tolerated.by The decreases in net cholesterol synthesis and increased fecal sterol excretion yielded nearly additive reductions in LDL-C for the coadministration significantly of ezetimibe and simvastatin.

Objective: .050). To assess the long-term efficacy and safety profile of ezetimibe 10 mg/day in patients with homozygous sitosterolemia. Methods: This was treatment an extension of a multi-centre, randomised, double-blind, placebo-controlled base study in which patients with homozygous sitosterolemia and plasma sitosterol concentrations tolerated. > 5 mg/dl were randomised 4 : 1 to ezetimibe 10 mg/day (n = 30) or placebo (n = 7)The for 8 weeks. Patients who successfully completed the base study with > 80% compliance to study medication were eligible to to enter two, successive, 1-year extension studies in which ezetimibe 10 mg/day was administered in an open-label manner. Patients remained on Overall their current treatment regimen (e.g. bile salt-binding resins, statins and low-sterol diet) during the base and extension studies. Patients had open-label to be off ezetimibe therapy for >/= 4 weeks prior to entering the first extension. Efficacy and safety/tolerability parameters were sitosterol evaluated every 12 and 26 weeks in the first and second years respectively. The primary efficacy end-point was mean percentage led change in plasma sitosterol from baseline to study end for the cohort of patients (n = 21) who successfully completed apolipoprotein the second extension study. Results: Treatment with ezetimibe 10 mg/day led to significant mean percentage reductions from baseline in plasma p concentrations of sitosterol (-43.9%; p < .001), campesterol (-50.8%; p < .001), low-density lipoprotein (LDL) sterols (-13.1%; p < .050),were total sterols (-10.3%; p < .050) and apolipoprotein (apo) B (-10.1%; p < .050). No significant changes from baseline were duration observed for lathosterol, high-density lipoprotein sterol, triglycerides or apo A-1. Maximal reductions in sitosterol and campesterol occurred within the first concentrations 52 weeks of treatment and were sustained for the duration of the study. For LDL sterol, total sterols and apo = B, maximal reductions were achieved early (by weeks 4 or 16) and waned slightly through the remainder of the study.manner. Overall ezetimibe 10 mg was well tolerated. Conclusion: In patients with homozygous sitoserolemia, long-term treatment with ezetimibe 10 mg/day for for 2 years was effective in reducing plasma plant sterol concentrations with an overall favourable safety and tolerability profile.

Using of spin-polarized scanning tunneling microscopy we show that the magnetic order of 1 monolayer Mn on W(001) is a spin spiral the propagating along 110 crystallographic directions. The spiral arises on the atomic scale with a period of about 2.2 nm, equivalent two to only 10 atomic rows. Ab initio calculations identify the spin spiral as a left-handed cycloid stabilized by the Dzyaloshinskii-Moriya Ab interaction, imposed by spin-orbit coupling, in the presence of softened ferromagnetic exchange coupling. Monte Carlo simulations explain the formation of Mn a nanoscale labyrinth pattern, originating from the coexistence of the two possible rotational domains, that is intrinsic to the system.of

Objective:EZE To assess the effect of ezetimibe (EZE) 40 mg/day on non-cholesterol sterol plasma concentrations in patients with homozygous sitosterolaemia (HoS).tendon Methods: This was a multi-centre, randomised, double-blind, placebo-controlled parallel group study. Twenty-seven patients (>/= 18 years) with HoS and plasma mg/day sitosterol levels > 5 mg/dl who had been taking EZE 10 mg/day for >/= 6 months prior to enrolment received chromatography, open-label EZE 10 mg/day for the duration of the study and were randomised 1 : 1 to blinded EZE 30 been mg/day (4 x EZE 10 mg tablets; n = 13) or placebo (1 x EZE 10 mg tablet and 3 with x matching placebo tablets; n = 14) for 26 weeks. Patients were permitted to remain on other ongoing treatments (e.g.EZE bile salt-binding resin, statin and/or low sterol diet). End-points included median per cent between-group changes from baseline in plasma sitosterol,Ezetimibe campesterol, lathosterol, low-density lipoprotein (LDL) sterols, LDL cholesterol (LDL-C) measured by gas-liquid chromatography, and Achilles tendon thickness size measured radiographically.campesterol Results: Ezetimibe 40 mg/day resulted in median per cent changes from baseline in plasma sitosterol levels of 3.3% vs.-10%in in the EZE 10 mg/day group, in plasma campesterol of - .5% vs.-9.7% in the EZE 10 mg/day group, and 1.1% in plasma lathosterol of .8% vs. 1.1% in the EZE 10 mg/day group (p = ns for all between-group differences).to Median per cent changes in the EZE 40 mg/day and EZE 10 mg/day groups, respectively, were 1.3% and % for 40 LDL sterols and 2.5% and 4.4% for LDL-C (p = ns for both between-group differences). At study end-point, Achilles tendon and thickness remained unchanged in the EZE 40 mg/day group and increased slightly in the EZE 10 mg/day group (2.2%), yielding for a non-significant between-group difference of -2.2%. EZE 40 mg/day was generally well tolerated. Conclusions: In patients with HoS, treatment with 10 EZE 40 mg/day for 26 weeks was no more effective at reducing plasma plant sterol concentrations vs. EZE 10 mg/day.concentrations EZE 40 mg/day had a safety and tolerability profile similar to EZE 10 mg/day.

OBJECTIVES:= The purpose of this study was to evaluate vascular effects of diet supplementation with plant sterol esters (PSE). BACKGROUND: Plant margarine sterol esters are used as food supplements to reduce cholesterol levels. Their effects on endothelial function, stroke, or atherogenesis are leads not known. METHODS: In mice, plasma sterol concentrations were correlated with endothelial function, cerebral lesion size, and atherosclerosis. Plasma and the tissue sterol concentrations were measured by gas-liquid chromatography-mass spectrometry in 82 consecutive patients with aortic stenosis. RESULTS: Compared with those or fed with normal chow (NC), wild-type mice fed with NC supplemented with 2% PSE showed increased plant sterol but equal atherogenesis cholesterol plasma concentrations. The PSE supplementation impaired endothelium-dependent vasorelaxation and increased cerebral lesion size after middle cerebral artery occlusion. To stenosis. test the effects of cholesterol-lowering by PSE, apolipoprotein E (ApoE)-/- mice were randomized to Western-type diet (WTD) with the addition E of PSE or ezetimibe (EZE). Compared with WTD, both interventions reduced plaque sizes; however, WTD + PSE showed larger plaques reduced compared with WTD + EZE (20.4 +/- 2.1% vs. 10. +/- 1.5%). Plant sterol plasma concentration strongly correlated with increased increased atherosclerotic lesion formation (r = .50). Furthermore, we examined plasma and aortic valve concentrations of plant sterol in 82 consecutive (20.4 patients with aortic stenosis. Patients eating PSE-supplemented margarine (n = 10) showed increased plasma concentrations and 5-fold higher sterol concentrations tissue in aortic valve tissue. CONCLUSIONS: Food supplementation with PSE impairs endothelial function, aggravates ischemic brain injury, effects atherogenesis in mice,increased and leads to increased tissue sterol concentrations in humans. Therefore, prospective studies are warranted that evaluate not only effects on levels. cholesterol reduction, but also on clinical endpoints.

OBJECTIVE:lowering The conversion of cholesterol into bile acids occurs via a long cascade of enzymatically regulated oxidative processes. Our aim was in to examine if an up-regulation of hepatic cholesterol 7alpha-hydroxylase (CYP7A1) in humans by cholestyramine, a bile acid-binding resin, has an 27-hydroxycholesterol effect on the degradation of brain-specific 24S-hydroxycholesterol. PATIENTS AND METHODS: Six normocholesterolemic male volunteers received 4 g cholestyramine b.i.d. for = 2 weeks in an open, prospective exploratory trial. Serum concentrations of lipoproteins and triglycerides were measured by routine enzymatic assays.by Sterols and oxysterols were measured by gas chromatography/mass spectrometry. RESULTS: Total and LDL-cholesterol decreased on the average by 9.3%(p serum = .002) and 19.8%(p = .001) after 2 weeks of treatment, respectively. Absolute serum concentrations of 7alpha-hydroxycholesterol, a marker prospective for bile acid production, increased 4-fold after 2 weeks, while 24S- and 27-hydroxycholesterol remained unchanged. Treatment with cholestyramine elevated serum respectively. levels of lathosterol, an indicator for the endogenous synthesis of cholesterol, by 146%(p = .009). CONCLUSION: In addition to and lowering serum concentrations of total cholesterol and LDL-cholesterol, cholestyramine at a dose rate of 4 g b.i.d. causes a significant CONCLUSION: increase in the CYP7A1 catalyzed 7alpha-hydroxylation of cholesterol and an up-regulation of endogenous cholesterol synthesis, as proven indirectly by an indicator increase in serum lathosterol levels. Total serum levels of 24S- and 27-hydroxycholesterol remained unchanged indicating that an up-regulation in CYP7A1 volunteers activity is not responsible for the subsequent oxidative degradation of these hydroxylated sterols.

OBJECTIVE:an Epidemiological studies have convincingly demonstrated a positive association between LDL-cholesterol (LDL-C) and coronary artery disease but, in the case of in HDL-C, there is an inverse association. Administration of high doses of the antifungal agent ketoconazole (800 mg/d) reduces serum concentrations in of total cholesterol and LDL-C and there is a tendency for an increase in HDL-C. Our goal was to examine assays whether high-dose itraconazole raises HDL-C in subjects with normal levels of cholesterol. PATIENTS AND METHODS: 8 male patients with onychomycosis cholesterol received 2 one-week cycles of treatment with itraconazole at a dose of 400 mg once daily in an open, prospective decrease exploratory trial. Serum levels of itraconazole and its active metabolite hydroxyitraconazole were determined using high-performance liquid chromatography at the end treatment of each treatment cycle. Fasting levels of serum lipoproteins and triglycerides were measured twice using routine enzymatic assays at the cycle. beginning and end of each cycle. The effects of itraconazole and hydroxyitraconazole on HDL-C metabolism were assessed in vitro using an a human Caco-2 cell line and analyzing apoA-I levels with an enzyme-linked immunosorbent assay. RESULTS: During itraconazole treatment total cholesterol .001). and LDL-C decreased on average by 12%(p < .001) and 17%(p < .001), respectively, whereas HDL-C increased by 12% 21%(p < .001). The ratio LDL: HDL-C, an index of atherogenic risk, decreased by 30%(p < .001). Incubation levels of Caco-2 cells in the presence of itraconazole and hydroxyitraconazole for 3 hours resulted in a significant increase in apoA-I concentration concentration in the medium (913 and 412%, respectively) compared with control. CONCLUSION: In addition to its inhibitory effect on cholesterol ketoconazole synthesis, high-dose itraconazole (400 mg/d) causes a significant decrease in serum LDL-C and, in contrast to ketoconazole, a significant increase is in HDL-C. In vitro studies with Caco-2 cells indicate that the latter observation might be caused by an increase in with apoA-I levels.

This compared study was undertaken to compare the ability of two plant sterols to reduceserum levels of lipids and to compare their The mechanism of action in nine children with severe familial hypercholesterolemia (total and low-density lipoprotein cholesterol concentrations averaged 9.57 mmol/L (370 magnitude mg/dl) and 7.87 mmol/L (301 mg/di)). After a 3-month strict diet, the children were given sitosterol, pastils (2 gm three 29% times a day) for 3 months, followed by a 7-month course of sitostanol ( .5 gm three times a day). Serum 7.87 lipoprotein levels and serum concentrations of campesterol and sitosterol were determined in all nine children, and the fecal excretion of levels neutral and acidic sterols were determined in seven children at the end of each therapeutic regimen. Sitosterol reduced low-density lipoprotein concentrations cholesterol levels by 20%(p< .01); sitostanol reduced low-density liloprotein cholesterol levels by 33% after 3 months and 29% after 7 p< .05 months (p< .01 compared with diet; p< .05 compared with sitosterol). Although sitosterol did not alter serum concentrations of campesterol and sitosterol,and a significant reduction did occur during sitostanol therapy (-47% and -51%, respectively; p< .01). Fecal excretion of neutral sterols increased from day 6.7 mg/kg per day during the control period to 9.7 mg/kg per day during sitosterol administration (p< .05), and to 12.6 control mg/kg per day during sitostanol administration (p< .05 compared with diet and sitosterol periods), indicating an increase in the inhibition of a intestinal cholesterol absorption. All children completed the study and no obvious side effects occurred. The data indicate that sitostanol, even with with a dose four-fold lower than that of sitosterol, was significantly more effective in reducing elevated levels of low-density lipoprotein cholesterol cholesterol, and the reduction in serum lipid levels was of the same magnitude as that observed with systemic lipid-lowering drugs.a These results suggest that sitostanol, a nonabsorbable plant sterol, could be the drug of choice for treating familial hypercholesterolemia in campesterol childhood.