Vitamin E combined with selenium inhibits atherosclerosis in hypercholesterolemic rabbits independently of effects on plasma cholesterol concentrations.Several antioxidants inhibit atherosclerosis. This study investigated the hypothesis that combining vitamin E, a lipophilic antioxidant, with vitamin C, a hydrophilic antioxidant, and/or selenium, a cofactor of peroxidases that detoxify lipid peroxides, would inhibit atherosclerosis more effectively than vitamin E alone. We also considered whether regional variation in inhibition of atherosclerosis by antioxidants would be associated with regional variation in aortic lipophilic antioxidants. Rabbits were fed an atherogenic diet (control) or an atherogenic diet supplemented with vitamin E, vitamins E and C, vitamin E+selenium, vitamins E and C+selenium, or probucol (positive control). Supplements were as follows: vitamin E, 146 IU/d; vitamin C, 791 mg/d; selenium, 22 microg/d; or probucol, 406 mg/d. Vitamin C did not influence atherosclerosis. After 22 weeks of treatment, rank order of aortic atherosclerosis was control>vitamin E (with or without vitamin C)>vitamin E+selenium (with or without vitamin C)>probucol. Antioxidant treatment reduced aortic cholesterol concentrations 21% to 56%, 29% to 86%, and 19% to 75% for the aortic arch, descending thoracic aorta, and abdominal aorta, respectively (P<0.025 to P<0.0003 by ANOVA), with slightly greatly reductions for areas of atherosclerotic lesions. Some treatments reduced plasma cholesterol concentrations, but none altered the distribution of cholesterol among lipoproteins. Corrected for differences in plasma cholesterol concentrations, aortic cholesterol concentrations were reduced up to 72% (P<0.02) by the antioxidant treatments, with equal reductions by vitamin E+selenium and by probucol. Aortic alpha-tocopherol standardized by aortic cholesterol as a measure of aortic lipids was lower in the abdominal aorta than in the aortic arch of rabbits not given alpha-tocopherol and increased relatively more in the abdominal aorta than in the aortic arch with alpha-tocopherol supplementation. The results of this study suggest that vitamin E+ selenium inhibited atherosclerosis as effectively as an equally hypocholesterolemic dose of probucol by a mechanism(s) that is in part independent of effects on plasma and lipoprotein cholesterol concentrations. The tendency for greater efficacy of antioxidant treatments in the abdominal aorta than aortic arch may relate to the lower concentrations of alpha-tocopherol in the abdominal aorta of unsupplemented rabbits.

Apolipoprotein E polymorphism in middle-aged Belgian men: phenotype distribution and relation to serum lipids and lipoproteins.Apo E phenotype was determined in 760 Belgian men, aged 35 to 59 years. Serum lipids and lipoproteins were related to the apo E polymorphism in 734 participants. By comparison with the most frequent apo E3/3 phenotype, the presence of the epsilon2 allele was associated with a lower serum total and non-HDL cholesterol, and with a lower apo B and a higher HDL cholesterol, independently of age, lifestyle factors and apo E concentration. In contrast, the presence of the epsilon4 allele was associated with a higher serum total and non-HDL cholesterol, and with a lower HDL cholesterol and a lower apo AI. The apo E phenotype explained 17.4% of the variance in apo E concentration; the proportion of the variance in total cholesterol, HDL cholesterol, apo AI and apo B levels explained by the apo E polymorphism was low but statistically significant. Among the lifestyle factors, waist to hip ratio was the only variable significantly associated with apo E concentration. The data suggest that besides the well-documented increasing effect on non-HDL cholesterol, the epsilon4 allele could further predispose to Coronary Heart Disease through a decreasing effect on HDL while the epsilon2 allele could exert a protective influence through both a decreasing effect on non-HDL cholesterol and an increasing effect on HDL cholesterol.

Infant-feeding patterns are related to blood cholesterol concentration in prepubertal children aged 5-11 y: the Fleurbaix-Laventie Ville Sante study.OBJECTIVE: Several studies, mainly in animals, but also in humans, have shown that diet in infancy is associated with differences in blood cholesterol concentrations later in life. The objective was to examine this relationship in children aged 5-11 y after taking into account their current diet and parental hypercholesterolemia. SETTING AND SUBJECTS: 251 prepubertal boys and 223 prepubertal girls enrolled in the schools in two little towns in northern France. DESIGN AND METHODS: Cross-sectional evaluation including measurements of cholesterol concentrations on capillary blood and a single weekday food intake record. Infant feeding patterns were obtained by questionnaire given to the mothers. RESULTS: 50% of the children had been breast-fed for a median duration of less than 2 months. Cow's milk was introduced in the diet as whole milk for 33% of the children. After adjustment for age, height, and sibship, capillary cholesterol concentration was lower in boys who had been breast fed (geometric mean: 4.4, 95% confidence interval of the mean: 4.2-4.6 mmol/L) than in those fed with formula (4.7, 4.5-4.8 mmol/L, P<0.03). In girls, breastfeeding had no significant effect on blood cholesterol concentration, which was associated with the type of cow's milk given in infancy: whole milk: 4.9 mmol/L (4.7-5. 2); totally or partially skimmed milk: 4.5 mmol/L (4.2-4.6), P<0.008. The current saturated fat and cholesterol intakes and parental hypercyholesterolemia were associated with current blood cholesterol concentration in children, but did not modify its relationship with infant feeding patterns. CONCLUSION: Results of the present study suggest that diet in infancy may have longstanding effect on lipid metabolism. Sponsorship: The study was supported by funds from Eridania Beghin-Say, Groupe Fournier, Lesieur and Nestle France, Roche Diagnostic and of the MGEN (Mutuelle Generale de l'Education Nationale, contract INSERM-MGEN #9158) and a grant from the Association de Langue Francaise pour l'Etude du Diabete et du Metabolisme (ALFEDIAM). European Journal of Clinical Nutrition (2000) 54, 114-119

Effects of a mixture of organisms, Lactobacillus acidophilus or Streptococcus faecalis on cholesterol metabolism in rats fed on a fat- and cholesterol-enriched diet.The effect of a mixture of organisms (a probiotic mixture) comprising Bacillus, Lactobacillus, Streptococcus, Clostridium, Saccharomyces and Candida (10(7-8) colony-forming units/g rice bran of each component) on lipid metabolism was compared with that of L. acidophilus and that of S. faecalis. There were four treatment groups: rice bran (control), the mixture of organisms, L. acidophilus or S. faecalis (30 g/kg) were given to rats in a fat- and cholesterol-enriched diet for 4 weeks. The serum total cholesterol concentration of the group fed on the mixture of organisms was reduced by 15-33% compared with the other groups at the end of the 4-week feeding period (P < 0.05). This group also had a lower hepatic cholesterol concentration (36-44%) than the two single-bacteria groups (P < 0.05). 3-Hydroxy-3-methylglutaryl-Co A reductase (NADPH; EC 1.1.1.34) activities of the mixed-organism and L. acidophilus groups were significantly lower (61-63%) than those of the other groups (P < 0.05); the activity of the S. faecalis group was also significantly lower (42%) than that of the control group (P < 0.05). The faecal cholesterol and bile acid concentrations of the mixed-organism group increased compared with those of the L. acidophilus and S. faecalis groups (P < 0.05). The capacity of the mixed-organism cells to bind bile salt in vitro was significantly higher (approximately 50%) than that of the single-bacteria cells (P < 0.05). On the other hand, cholesterol micelle formation for the mixed-organism cells was significantly (approximately 9%) lower than that of the single-bacteria cells (P < 0.05). These results indicate that the mixture of organisms decreased the synthesis of cholesterol in the liver and increased the loss of steroids from the intestine, in rats. Thus, the mixture of organisms had a hypocholesterolaemic role.

Ileorectostomy or cecectomy but not colectomy abolishes the plasma cholesterol-lowering effect of dietary beet fiber in rats.Adult male rats were fed a cholesterol-free diet with no added fiber (fiber-free) or with 10% cellulose or beet fiber. After 7 d of feeding, plasma total cholesterol concentrations were significantly lower in rats fed beet fiber than in those fed fiber-free or cellulose diets. This difference was due mainly to lower HDL cholesterol concentrations and remained significant for 28 d. The hypocholesterolemic effect of beet fiber relative to fiber-free disappeared when the cecum and colon were concurrently resected (ileorectostomy). Plasma cholesterol concentrations were the same in colectomized rats as in sham-operated rats fed the same diet and significantly lower in animals fed the beet fiber diet than in those fed the fiber-free diet. In cecectomized rats fed beet fiber, plasma cholesterol concentrations were intermediate between sham-operated rats fed the beet fiber diet and cecectomized or sham-operated rats fed the fiber-free diet. Fecal bile acid excretion was higher in rats fed the beet fiber diet than in those fed the fiber-free diet but did not correlate with plasma total cholesterol concentration. In rats with intact ceca, cecal total and individual short-chain fatty acids correlated negatively with plasma total cholesterol concentration. Dietary beet fiber lowers plasma cholesterol concentrations in rats, and the lower digestive tract, especially the cecum, seems to be necessary for this effect.

Inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). 7. Development of a series of substituted N-phenyl-N'-[(1-phenylcyclopentyl)methyl]ureas with enhanced hypocholesterolemic activity.We recently described our initial structure-activity relationship (SAR) studies on a series of N-phenyl-N'-aralkyl- and N-phenyl-N'-(1-phenylcycloalkyl)ureas as inhibitors of acyl-CoA: cholesterol acyltransferase (ACAT). From this series of analogs, compound 1 (PD 129337) was identified as a potent inhibitor of ACAT with an IC50 value of 17 nM. It was also shown to dose-dependently lower plasma cholesterol in cholesterol-fed rats. However, further investigation led to the suggestion that this compound was poorly absorbed, due to a lack of efficacy when administered by gavage in an aqueous vehicle. To overcome this deficiency, we continued our SAR study on this novel series of ACAT inhibitors using an acute in vivo screen in which the compounds are administered to rats in an aqueous, CMC/Tween suspension vehicle. Modification of the N'-phenyl moiety by incorporating functional groups which were amenable to forming salts and/or polar groups to reduce lipophilicity led to the identification of several inhibitors which displayed excellent efficacy employing this protocol. Overall, substitution on the phenyl ring in the ortho, meta, or para positions led to inhibitors with only a slight decrease in potency in vitro compared to the parent unsubstituted compound. Bulkier groups in the para position tended to lower the ACAT inhibitory activity in vitro. Polar groups, such as carboxyl (33,34), lowered in vitro activity significantly, suggesting that polar-ionic interactions are disfavored for the enzyme activity. From this series, compound 28 was evaluated further in secondary in vivo screens. In a chronic cholesterol-fed rat model of hypercholesterolemia, compound 28 dose-dependently reduced nonHDL cholesterol and significantly elevated HDL cholesterol. It showed significantly greater aqueous solubility than the parent compound 1. However, it was shown to cause adrenal toxicity in guinea pigs. This led us to design a series of homologs (44-51) with increased basicity and lower lipophilicity. Some of these compounds were more potent ACAT inhibitors in vitro and demonstrated excellent hypocholesterolemic activity in vivo. Interestingly, compound 45, unlike 28, did not produce adrenal toxicity in guinea pigs and demonstrated excellent lipid-modulating activity in the chronic model of preestablished dyslipidemia in rats.

Increased reverse cholesterol transport in athletes.Proposed mechanisms for the cardioprotective benefits of exercise include decreased lipid deposition and increased reverse cholesterol transport (RCT). RCT involves the efflux of tissue free cholesterol into high-density lipoprotein (HDL) particles, esterification by lecithin:cholesterol acyltransferase (LCAT), transfer to other lipoproteins by cholesterol ester transfer proteins (CETP), and liver excretion. We tested the hypothesis that RCT is enhanced in athletes and that this can occur without large increases in plasma HDL cholesterol (HDL-C) mass levels. Fasting venous blood was drawn from 13 sedentary men and 11 athletes exercising at the rate of 5,185 +/- 501 kcal/wk. Compared with controls, athletes had similar age, body mass index (BMI), HDL-C (P > .1) and apolipoprotein (apo) A-1 (P > .5) levels, and lower low-density lipoprotein cholesterol (LDL-C) (P < .05) and apo B (P < .03) levels. The net mass of free cholesterol transported (NMCT) out of cultured human fibroblasts into the athletes' serum was greater than that for controls (25.5 +/- 8.0 v 7.1 +/- 2.6 micrograms/mL/h, P = .048). The efflux component of this transport correlated with HDL-C and apo A-1 levels and was similar between groups (P = .24), suggesting that athletes' antiatherogenic NMCT findings were due to decreased cholesterol influx into the cells. Athletes had increased plasma LCAT (20.3 +/- 2.1 v 13.9 +/- 1.5 micrograms/mL/h, P = .028) and CETP activities (69.7 +/- 4.5 v 21.5 +/- 4.8%/mL/h, P < .001). The NMCT positively correlated with CETP and LCAT activities and inversely with apo B levels and the cardiac risk ratio apo B/A-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Gallstone composition in relation to buoyancy at oral cholecystography.Although it is recognized that some gallstones float at oral cholecystography, the reasons for this are not known. To determine how stone type and composition are related to stone buoyancy, the authors analyzed gallstones from 90 patients in the National Cooperative Gallstone Study. Seventeen patients had floating and 73 had nonfloating radiolucent stones at oral cholecystography. Stone analysis showed that all 17 floating stones were cholesterol stones; 64 of the nonfloating stones were cholesterol stones, while nine were pigment stones. The cholesterol contents of floating and nonfloating cholesterol stones were similar, 90.4% +/- 1.7 and 87.0% +/- 1.2 of stone weight, respectively. The calcium salt content of the nonfloating cholesterol stones was 3.2% +/- 0.6, while that of the floating cholesterol stones was only 1.1% +/- 0.4 (P = .02). The results indicate that floating gallstones are cholesterol stones with a significantly lower calcium salt content than that of nonfloating cholesterol stones.

Psyllium husk. I: Effect on plasma lipoproteins, cholesterol metabolism, and atherosclerosis in African green monkeys.Psyllium's effects on plasma and lipoprotein cholesterol concentrations, cholesterol metabolism, and diet-induced atherosclerosis were studied in adult male African green monkeys (Cercopithecus aethiops). Animals were fed for 3.5 y one of three experimental diets: low-cholesterol cellulose (LCC), high-cholesterol cellulose (HCC), or high-cholesterol psyllium (HCP). The LCC and HCP groups had significantly (P less than 0.05) lower plasma cholesterol concentrations (39% lower) at 1 mo than did the HCC group. These responses persisted throughout the study. Plasma cholesterol changes were due to a reduction in intermediate-density and low-density lipoproteins; very-low and high-density-lipoprotein concentrations were similar among groups. Aortic atherosclerosis, evaluated as percent sudanophilia at 3.5 y, was lowest in the LCC group, intermediate in the HCP group, and highest in the HCC group. Cholesterol absorption, neutral steroid and fat excretion, HMGCoA reductase activity (in intestine and liver), and body weight were unrelated to psyllium's hypocholesterolemic effects.

Vitamin E inhibits fish oil-induced hyperlipidemia and tissue lipid peroxidation in hamsters.Previous research has linked hyperlipidemia with increased serum concentrations of lipid peroxidation products; however, a specific association between diet-induced oxidative stress and hyperlipidemia has not been studied. In the present study, the relationship between tissue lipid peroxidation and hyperlipidemia induced by ingestion of fish oil was examined. In Experiment 1, male Golden Syrian hamsters were fed semipurified diets composed of 1.6 wt% safflower oil plus 15.0 wt% of either butterfat (BF), safflower oil (SAFF), or high-cholesterol menhaden oil [MHO(H-CHOL)] semipurified diets for 27 d. The cholesterol contents of the diets were adjusted to 0.088%. The MHO(H-CHOL)-fed hamsters exhibited higher serum concentrations of total cholesterol, triglycerides, apolipoprotein B, and lipid peroxides when compared to the BF and SAFF diet groups. In a further study (Experiment 2), hamsters were fed for 27 d three dietary treatments: (i) MHO(H-CHOL) with no vitamin E content; (ii) a low-cholesterol menhaden oil containing high concentrations of vitamin E (2.5 mg tocopherol/g oil or dietary concentrations of 375 mg/kg) [MHO(L-CHOL) + E]; and (iii) the MHO(L-CHOL + E) with added cholesterol (595 mg/kg) [MHO(L-CHOL) + CHOL + E] to match the cholesterol content of the MHO(H-CHOL). The MHO(L-CHOL) + E and MHO(L-CHOL) + CHOL + E diet groups showed lower concentrations of serum cholesterol, triglycerides, and hepatic lipid peroxides than the MHO(H-CHOL)-treated group. Moreover, in contrast to the hypercholesterolemia caused by the MHO(H-CHOL) feeding, the MHO(L-CHOL)+ E and MHO(L-CHOL) + CHOL + E diets did not show a serum cholesterol-elevating action. This study supports the hypothesis that oxidative stress in the Syrian hamster could play a causal role in dietary-induced hyperlipidemia which can be inhibited by high vitamin E intake.